Analysis of a Stretched Derivative Aircraft with Open Rotor Propulsion

NASA Technical Reports Server (NTRS)

Berton, Jeffrey J.; Hendricks, Eric S.; Haller, William J.; Guynn, Mark D.

2015-01-01

Research into advanced, high-speed civil turboprops received significant attention during the 1970s and 1980s when fuel efficiency was the driving focus of U.S. aeronautical research. But when fuel prices declined sharply there was no longer sufficient motivation to continue maturing the technology. Recent volatility in fuel prices and increasing concern for aviation's environmental impact, however, have renewed interest in unducted, open rotor propulsion and revived research by NASA and a number of engine manufacturers. Recently, NASA and General Electric have teamed to conduct several investigations into the performance and noise of an advanced, single-aisle transport with open rotor propulsion. The results of these initial studies indicate open rotor engines have the potential to provide significant reduction in fuel consumption compared to aircraft using turbofan engines with equivalent core technology. In addition, noise analysis of the concept indicates that an open rotor aircraft in the single-aisle transport class would be able to meet current noise regulations with margin. The behavior of derivative open rotor transports is of interest. Heavier, "stretched" derivative aircraft tend to be noisier than their lighter relatives. Of particular importance to the business case for the concept is how the noise margin changes relative to regulatory limits within a family of similar open rotor aircraft. The subject of this report is a performance and noise assessment of a notional, heavier, stretched derivative airplane equipped with throttle-push variants of NASA's initial open rotor engine design.

First NASA/Industry High Speed Research Program Nozzle Symposium

NASA Technical Reports Server (NTRS)

Long-Davis, Mary Jo

1999-01-01

The First High Speed Research (HSR) Nozzle Symposium was hosted by NASA Lewis Research Center on November 17-19, 1992 in Cleveland, Ohio, and was sponsored by the HSR Source Noise Working Group. The purpose of this symposium was to provide a national forum for the government, industry, and university participants in the program to present and discuss important low noise nozzle research results and technology issues related to the development of appropriate nozzles for a commercially viable, environmentally compatible, U.S. High-Speed Civil Transport. The HSR Phase I research program was initiated in FY90 and is approaching the first major milestone (end of FY92) relative to an initial FAR 36 Stage 3 nozzle noise assessment. Significant research results relative to that milestone were presented. The opening session provided a brief overview of the Program and status of the Phase H plan. The next five sessions were technically oriented and highlighted recent significant analytical and experimental accomplishments. The last Session included a panel discussion by the Session Chairs, summarizing the progress seen to date and discussing issues relative to further advances in technology necessary to achieve the Program Goals. Attendance at the Symposium was by invitation only and included only industry, academic, and government participants who are actively involved in the High-Speed Research Program. The technology presented in this meeting is considered commercially sensitive.

Low Speed and High Speed Correlation of SMART Active Flap Rotor Loads

NASA Technical Reports Server (NTRS)

Kottapalli, Sesi B. R.

2010-01-01

Measured, open loop and closed loop data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. One open loop high-speed case and four closed loop cases are considered. The closed loop cases include three high-speed cases and one low-speed case. Two of these high-speed cases include a 2 deg flap deflection at 5P case and a test maximum-airspeed case. This study follows a recent, open loop correlation effort that used a simple correction factor for the airfoil pitching moment Mach number. Compared to the earlier effort, the current open loop study considers more fundamental corrections based on advancing blade aerodynamic conditions. The airfoil tables themselves have been studied. Selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the closed loop condition, the effect of the flap actuator is modeled by increased flap hinge stiffness. Overall, the open loop correlation is reasonable, thus confirming the basic correctness of the current semi-empirical modifications; the closed loop correlation is also reasonable considering that the current flap model is a first generation model. Detailed correlation results are given in the paper.

Open Rotor - Analysis of Diagnostic Data

NASA Technical Reports Server (NTRS)

Envia, Edmane

2011-01-01

NASA is researching open rotor propulsion as part of its technology research and development plan for addressing the subsonic transport aircraft noise, emission and fuel burn goals. The low-speed wind tunnel test for investigating the aerodynamic and acoustic performance of a benchmark blade set at the approach and takeoff conditions has recently concluded. A high-speed wind tunnel diagnostic test campaign has begun to investigate the performance of this benchmark open rotor blade set at the cruise condition. Databases from both speed regimes will comprise a comprehensive collection of benchmark open rotor data for use in assessing/validating aerodynamic and noise prediction tools (component & system level) as well as providing insights into the physics of open rotors to help guide the development of quieter open rotors.

Optimal symmetric flight with an intermediate vehicle model

NASA Technical Reports Server (NTRS)

Menon, P. K. A.; Kelley, H. J.; Cliff, E. M.

1983-01-01

Optimal flight in the vertical plane with a vehicle model intermediate in complexity between the point-mass and energy models is studied. Flight-path angle takes on the role of a control variable. Range-open problems feature subarcs of vertical flight and singular subarcs. The class of altitude-speed-range-time optimization problems with fuel expenditure unspecified is investigated and some interesting phenomena uncovered. The maximum-lift-to-drag glide appears as part of the family, final-time-open, with appropriate initial and terminal transient exceeding level-flight drag, some members exhibiting oscillations. Oscillatory paths generally fail the Jacobi test for durations exceeding a period and furnish a minimum only for short-duration problems.

Long-term safety and efficacy of dalfampridine for walking impairment in patients with multiple sclerosis: Results of open-label extensions of two Phase 3 clinical trials

PubMed Central

Goodman, Andrew D; Bethoux, Francois; Brown, Theodore R; Schapiro, Randall T; Cohen, Ron; Marinucci, Lawrence N; Henney, Herbert R

2015-01-01

Background: In Phase 3 double-blind trials (MS-F203 and MS-F204), dalfampridine extended release tablets 10 mg twice daily (dalfampridine-ER; prolonged-release fampridine in Europe; fampridine modified or sustained release elsewhere) improved walking speed relative to placebo in patients with multiple sclerosis (MS). Objectives: Evaluation of long-term safety and efficacy of dalfampridine-ER in open-label extensions (MS-F203EXT, MS-F204EXT). Methods: Patients received dalfampridine-ER 10 mg twice daily; and had Timed 25-Foot Walk (T25FW) assessments at 2, 14 and 26 weeks, and then every 6 months. Subjects were categorized as dalfampridine-ER responders or non-responders, based on their treatment response in the double-blind parent trials that assessed T25FW. Results: We had 269 patients enter MS-F203EXT and 154 patients complete it; for a maximum exposure of 5 years. We had 214 patients enter MS-F204EXT and 146 complete it; for a maximum exposure of 3.3 years. No new safety signals emerged and dalfampridine-ER tolerability was consistent with the double-blind phase. Improvements in walking speed were lost after dalfampridine-ER was discontinued in the parent trial, but returned by the 2-week assessment after re-initiation of the drug. Throughout the extensions, mean improvement in walking speed declined, but remained improved, among the double-blind responders as compared with non-responders. Conclusions: The dalfamipridine-ER safety profile was consistent with the parent trials. Although walking speed decreased over time, dalfampridine-ER responders continued to show improved walking speed, which was sustained compared with non-responders. PMID:25583832

Dynamic Torsional and Cyclic Fracture Behavior of ProFile Rotary Instruments at Continuous or Reciprocating Rotation as Visualized with High-speed Digital Video Imaging.

PubMed

Tokita, Daisuke; Ebihara, Arata; Miyara, Kana; Okiji, Takashi

2017-08-01

This study examined the dynamic fracture behavior of nickel-titanium rotary instruments in torsional or cyclic loading at continuous or reciprocating rotation by means of high-speed digital video imaging. The ProFile instruments (size 30, 0.06 taper; Dentsply Maillefer, Ballaigues, Switzerland) were categorized into 4 groups (n = 7 in each group) as follows: torsional/continuous (TC), torsional/reciprocating (TR), cyclic/continuous (CC), and cyclic/reciprocating (CR). Torsional loading was performed by rotating the instruments by holding the tip with a vise. For cyclic loading, a custom-made device with a 38° curvature was used. Dynamic fracture behavior was observed with a high-speed camera. The time to fracture was recorded, and the fractured surface was examined with scanning electron microscopy. The TC group initially exhibited necking of the file followed by the development of an initial crack line. The TR group demonstrated opening and closing of a crack according to its rotation in the cutting and noncutting directions, respectively. The CC group separated without any detectable signs of deformation. In the CR group, initial crack formation was recognized in 5 of 7 samples. The reciprocating rotation exhibited a longer time to fracture in both torsional and cyclic fatigue testing (P < .05). The scanning electron microscopic images showed a severely deformed surface in the TR group. The dynamic fracture behavior of NiTi rotary instruments, as visualized with high-speed digital video imaging, varied between the different modes of rotation and different fatigue testing. Reciprocating rotation induced a slower crack propagation and conferred higher fatigue resistance than continuous rotation in both torsional and cyclic loads. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

GMODWeb: a web framework for the generic model organism database

PubMed Central

O'Connor, Brian D; Day, Allen; Cain, Scott; Arnaiz, Olivier; Sperling, Linda; Stein, Lincoln D

2008-01-01

The Generic Model Organism Database (GMOD) initiative provides species-agnostic data models and software tools for representing curated model organism data. Here we describe GMODWeb, a GMOD project designed to speed the development of model organism database (MOD) websites. Sites created with GMODWeb provide integration with other GMOD tools and allow users to browse and search through a variety of data types. GMODWeb was built using the open source Turnkey web framework and is available from . PMID:18570664

Validation of zero-order feedback strategies for medium range air-to-air interception in a horizontal plane

NASA Technical Reports Server (NTRS)

Shinar, J.

1982-01-01

A zero order feedback solution of a variable speed interception game between two aircraft in the horizontal plane, obtained by using the method of forced singular perturbation (FSP), is compared with the exact open loop solution. The comparison indicates that for initial distances of separation larger than eight turning radii of the evader, the accuracy of the feedback approximation is better than one percent. The result validates the zero order FSP approximation for medium range air combat analysis.

Noise exposure in convertible automobiles.

PubMed

Mikulec, A A; Lukens, S B; Jackson, L E; Deyoung, M N

2011-02-01

To quantify the noise exposure received while driving a convertible automobile with the top open, compared with the top closed. Five different convertible automobiles were driven, with the top both closed and open, and noise levels measured. The cars were tested at speeds of 88.5, 104.6 and 120.7 km/h. When driving with the convertible top open, the mean noise exposure ranged from 85.3 dB at 88.5 km/h to 89.9 dB at 120.7 km/h. At the tested speeds, noise exposure increased by an average of 12.4-14.6 dB after opening the convertible top. Driving convertible automobiles at speeds exceeding 88.5 km/h, with the top open, may result in noise exposure levels exceeding recommended limits, especially when driving with the convertible top open for prolonged periods.

Development of the simulation system {open_quotes}IMPACT{close_quotes} for analysis of nuclear power plant severe accidents

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

Naitoh, Masanori; Ujita, Hiroshi; Nagumo, Hiroichi

1997-07-01

The Nuclear Power Engineering Corporation (NUPEC) has initiated a long-term program to develop the simulation system {open_quotes}IMPACT{close_quotes} for analysis of hypothetical severe accidents in nuclear power plants. IMPACT employs advanced methods of physical modeling and numerical computation, and can simulate a wide spectrum of senarios ranging from normal operation to hypothetical, beyond-design-basis-accident events. Designed as a large-scale system of interconnected, hierarchical modules, IMPACT`s distinguishing features include mechanistic models based on first principles and high speed simulation on parallel processing computers. The present plan is a ten-year program starting from 1993, consisting of the initial one-year of preparatory work followed bymore » three technical phases: Phase-1 for development of a prototype system; Phase-2 for completion of the simulation system, incorporating new achievements from basic studies; and Phase-3 for refinement through extensive verification and validation against test results and available real plant data.« less

Isokinetic air sampler

DOEpatents

Sehmel, George A.

1979-01-01

An isokinetic air sampler includes a filter, a holder for the filter, an air pump for drawing air through the filter at a fixed, predetermined rate, an inlet assembly for the sampler having an inlet opening therein of a size such that isokinetic air sampling is obtained at a particular wind speed, a closure for the inlet opening and means for simultaneously opening the closure and turning on the air pump when the wind speed is such that isokinetic air sampling is obtained. A system incorporating a plurality of such samplers provided with air pumps set to draw air through the filter at the same fixed, predetermined rate and having different inlet opening sizes for use at different wind speeds is included within the ambit of the present invention as is a method of sampling air to measure airborne concentrations of particulate pollutants as a function of wind speed.

Overall impact of speed-related initiatives and factors on crash outcomes.

PubMed

D'Elia, A; Newstead, S; Cameron, M

2007-01-01

From December 2000 until July 2002 a package of speed-related initiatives and factors took place in Victoria, Australia. The broad aim of this study was to evaluate the overall impact of the package on crash outcomes. Monthly crash counts and injury severity proportions were assessed using Poisson and logistic regression models respectively. The model measured the overall effect of the package after adjusting as far as possible for non-speed road safety initiatives and socio-economic factors. The speed-related package was associated with statistically significant estimated reductions in casualty crashes and suggested reductions in injury severity with trends towards increased reductions over time. From December 2000 until July 2002, three new speed enforcement initiatives were implemented in Victoria, Australia. These initiatives were introduced in stages and involved the following key components: More covert operations of mobile speed cameras, including flash-less operations; 50% increase in speed camera operating hours; and lowering of cameras' speed detection threshold. In addition, during the period 2001 to 2002, the 50 km/h General Urban Speed Limit (GUSL) was introduced (January 2001), there was an increase in speed-related advertising including the "Wipe Off 5" campaign, media announcements were made related to the above enforcement initiatives and there was a speeding penalty restructure. The above elements combine to make up a package of speed-related initiatives and factors. The package represents a broad, long term program by Victorian government agencies to reduce speed based on three linked strategies: more intensive Police enforcement of speed limits to deter potential offenders, i.e. the three new speed enforcement initiatives just described - supported by higher penalties; a reduction in the speed limit on local streets throughout Victoria from 60 km/h to 50 km/h; and provision of information using the mass media (television, radio and billboard) to reinforce the benefits of reducing low level speeding - the central message of "Wipe Off 5". These strategies were implemented across the entire state of Victoria with the intention of covering as many road users as possible. This study aimed to evaluate the overall effectiveness of the speed-related package. The study objectives were: to document the increased speed camera activity in each speed limit zone and in Melbourne compared with the rest of Victoria; to evaluate the overall effect on crash outcomes of the package; to account as far as possible for the effect on crash outcomes of non-speed road safety initiatives and socio-economic factors, which would otherwise influence the speed-related package evaluation; and to examine speed trends in Melbourne and on Victorian rural highways, especially the proportions of vehicles travelling at excessive speeds. This paper presents the results of the evaluation of the overall impact on crash outcomes associated with the speed-related package, after adjusting as far as possible for the effect of non-speed road safety initiatives and socio-economic factors. D'Elia, Newstead and Cameron (2007) document the study results in full.

49 CFR 236.503 - Automatic brake application; initiation when predetermined rate of speed exceeded.

Code of Federal Regulations, 2011 CFR

2011-10-01

... predetermined rate of speed exceeded. 236.503 Section 236.503 Transportation Other Regulations Relating to... § 236.503 Automatic brake application; initiation when predetermined rate of speed exceeded. An automatic train control system shall operate to initiate an automatic brake application when the speed of...

49 CFR 236.503 - Automatic brake application; initiation when predetermined rate of speed exceeded.

Code of Federal Regulations, 2010 CFR

2010-10-01

... predetermined rate of speed exceeded. 236.503 Section 236.503 Transportation Other Regulations Relating to... § 236.503 Automatic brake application; initiation when predetermined rate of speed exceeded. An automatic train control system shall operate to initiate an automatic brake application when the speed of...

On the finite element modeling of the asymmetric cracked rotor

NASA Astrophysics Data System (ADS)

AL-Shudeifat, Mohammad A.

2013-05-01

The advanced phase of the breathing crack in the heavy duty horizontal rotor system is expected to be dominated by the open crack state rather than the breathing state after a short period of operation. The reason for this scenario is the expected plastic deformation in crack location due to a large compression stress field appears during the continuous shaft rotation. Based on that, the finite element modeling of a cracked rotor system with a transverse open crack is addressed here. The cracked rotor with the open crack model behaves as an asymmetric shaft due to the presence of the transverse edge crack. Hence, the time-varying area moments of inertia of the cracked section are employed in formulating the periodic finite element stiffness matrix which yields a linear time-periodic system. The harmonic balance method (HB) is used for solving the finite element (FE) equations of motion for studying the dynamic behavior of the system. The behavior of the whirl orbits during the passage through the subcritical rotational speeds of the open crack model is compared to that for the breathing crack model. The presence of the open crack with the unbalance force was found only to excite the 1/2 and 1/3 of the backward critical whirling speed. The whirl orbits in the neighborhood of these subcritical speeds were found to have nearly similar behavior for both open and breathing crack models. While unlike the breathing crack model, the subcritical forward whirling speeds have not been observed for the open crack model in the response to the unbalance force. As a result, the behavior of the whirl orbits during the passage through the forward subcritical rotational speeds is found to be enough to distinguish the breathing crack from the open crack model. These whirl orbits with inner loops that appear in the neighborhood of the forward subcritical speeds are then a unique property for the breathing crack model.

Overall Impact of Speed-Related Initiatives and Factors on Crash Outcomes

PubMed Central

D’Elia, A.; Newstead, S.; Cameron, M.

2007-01-01

From December 2000 until July 2002 a package of speed-related initiatives and factors took place in Victoria, Australia. The broad aim of this study was to evaluate the overall impact of the package on crash outcomes. Monthly crash counts and injury severity proportions were assessed using Poisson and logistic regression models respectively. The model measured the overall effect of the package after adjusting as far as possible for non-speed road safety initiatives and socio-economic factors. The speed-related package was associated with statistically significant estimated reductions in casualty crashes and suggested reductions in injury severity with trends towards increased reductions over time. From December 2000 until July 2002, three new speed enforcement initiatives were implemented in Victoria, Australia. These initiatives were introduced in stages and involved the following key components: More covert operations of mobile speed cameras, including flash-less operations; 50% increase in speed camera operating hours; and lowering of cameras’ speed detection threshold. In addition, during the period 2001 to 2002, the 50 km/h General Urban Speed Limit (GUSL) was introduced (January 2001), there was an increase in speed-related advertising including the “Wipe Off 5” campaign, media announcements were made related to the above enforcement initiatives and there was a speeding penalty restructure. The above elements combine to make up a package of speed-related initiatives and factors. The package represents a broad, long term program by Victorian government agencies to reduce speed based on three linked strategies: more intensive Police enforcement of speed limits to deter potential offenders, i.e. the three new speed enforcement initiatives just described - supported by higher penalties; a reduction in the speed limit on local streets throughout Victoria from 60 km/h to 50 km/h; and provision of information using the mass media (television, radio and billboard) to reinforce the benefits of reducing low level speeding - the central message of “Wipe Off 5”. These strategies were implemented across the entire state of Victoria with the intention of covering as many road users as possible. PMID:18184508

Battle for Climate and Scarcity Rents: Beyond the Linear-Quadratic Case.

PubMed

Kagan, Mark; van der Ploeg, Frederick; Withagen, Cees

Industria imports oil, produces final goods and wishes to mitigate global warming. Oilrabia exports oil and buys final goods from the other country. Industria uses the carbon tax to impose an import tariff on oil and steal some of Oilrabia's scarcity rent. Conversely, Oilrabia has monopoly power and sets the oil price to steal some of Industria's climate rent. We analyze the relative speeds of oil extraction and carbon accumulation under these strategic interactions for various production function specifications and compare these with the efficient and competitive outcomes. We prove that for the class of HARA production functions, the oil price is initially higher and subsequently lower in the open-loop Nash equilibrium than in the efficient outcome. The oil extraction rate is thus initially too low and in later stages too high. The HARA class includes linear, loglinear and semi-loglinear demand functions as special cases. For non-HARA production functions, Oilrabia may in the open-loop Nash equilibrium initially price oil lower than the efficient level, thus resulting in more oil extraction and climate damages. We also contrast the open-loop Nash and efficient outcomes numerically with the feedback Nash outcomes. We find that the optimal carbon tax path in the feedback Nash equilibrium is flatter than in the open-loop Nash equilibrium. It turns out that for certain demand functions using the carbon tax as an import tariff may hurt consumers' welfare as the resulting user cost of oil is so high that the fall in welfare wipes out the gain from higher tariff revenues.

DISP: Optimizations towards Scalable MPI Startup

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

Fu, Huansong; Pophale, Swaroop S; Gorentla Venkata, Manjunath

2016-01-01

Despite the popularity of MPI for high performance computing, the startup of MPI programs faces a scalability challenge as both the execution time and memory consumption increase drastically at scale. We have examined this problem using the collective modules of Cheetah and Tuned in Open MPI as representative implementations. Previous improvements for collectives have focused on algorithmic advances and hardware off-load. In this paper, we examine the startup cost of the collective module within a communicator and explore various techniques to improve its efficiency and scalability. Accordingly, we have developed a new scalable startup scheme with three internal techniques, namelymore » Delayed Initialization, Module Sharing and Prediction-based Topology Setup (DISP). Our DISP scheme greatly benefits the collective initialization of the Cheetah module. At the same time, it helps boost the performance of non-collective initialization in the Tuned module. We evaluate the performance of our implementation on Titan supercomputer at ORNL with up to 4096 processes. The results show that our delayed initialization can speed up the startup of Tuned and Cheetah by an average of 32.0% and 29.2%, respectively, our module sharing can reduce the memory consumption of Tuned and Cheetah by up to 24.1% and 83.5%, respectively, and our prediction-based topology setup can speed up the startup of Cheetah by up to 80%.« less

Vehicle speed affects both pre-skid braking kinematics and average tire/roadway friction.

PubMed

Heinrichs, Bradley E; Allin, Boyd D; Bowler, James J; Siegmund, Gunter P

2004-09-01

Vehicles decelerate between brake application and skid onset. To better estimate a vehicle's speed and position at brake application, we investigated how vehicle deceleration varied with initial speed during both the pre-skid and skidding intervals on dry asphalt. Skid-to-stop tests were performed from four initial speeds (20, 40, 60, and 80 km/h) using three different grades of tire (economy, touring, and performance) on a single vehicle and a single road surface. Average skidding friction was found to vary with initial speed and tire type. The post-brake/pre-skid speed loss, elapsed time, distance travelled, and effective friction were found to vary with initial speed. Based on these data, a method using skid mark length to predict vehicle speed and position at brake application rather than skid onset was shown to improve estimates of initial vehicle speed by up to 10 km/h and estimates of vehicle position at brake application by up to 8 m compared to conventional methods that ignore the post-brake/pre-skid interval. Copyright 2003 Elsevier Ltd.

Protective Effectiveness of Porous Shields Under the Influence of High-Speed Impact Loading

NASA Astrophysics Data System (ADS)

Kramshonkov, E. N.; Krainov, A. V.; Shorohov, P. V.

2016-02-01

The results of numerical simulations of a compact steel impactor with the aluminum porous shields under high-speed shock loading are presented. The porosity of barrier varies in wide range provided that its mass stays the same, but the impactor has always equal (identical) mass. Here presented the final assessment of the barrier perforation speed depending on its porosity and initial shock speed. The range of initial impact speed varies from 1 to 10 km/s. Physical phenomena such as: destruction, melting, vaporization of a interacting objects are taken into account. The analysis of a shield porosity estimation disclosed that the protection effectiveness of porous shield reveals at the initial impact speed grater then 1.5 km/s, and it increases when initial impact speed growth.

Frequency of open windows in motor vehicles under varying temperature conditions: a videotape survey in Central North Carolina during 2001.

PubMed

Long, Tom; Johnson, Ted; Ollison, Will

2004-07-01

Air pollution exposures in the motor vehicle cabin are significantly affected by air exchange rate, a function of vehicle speed, window position, vent status, fan speed, and air conditioning use. A pilot study conducted in Houston, Texas, during September 2000 demonstrated that useful information concerning the position of windows, sunroofs, and convertible tops as a function of temperature and vehicle speed could be obtained through the use of video recorders. To obtain similar data representing a wide range of temperature and traffic conditions, a follow-up study was conducted in and around Chapel Hill, North Carolina at five sites representing a central business district, an arterial road, a low-income commercial district, an interstate highway, and a rural road. Each site permitted an elevated view of vehicles as they proceeded through a turn, thereby exposing all windows to the stationary camcorder. A total of 32 videotaping sessions were conducted between February and October 2001, in which temperature varied from 41 degrees F to 93 degrees F and average vehicle speed varied from 21 to 77 mph. The resulting video tapes were processed to create a vehicle-specific database that included site location, date, time, vehicle type, vehicle color, vehicle age, window configuration, number of windows in each of three position categories (fully open, partially open, and closed), meteorological factors, and vehicle speed. Of the 4715 vehicles included in the database, 1905 (40.4%) were labeled as "open," indicating a window, sunroof, or convertible top was fully or partially open. Stepwise linear regression analyses indicated that "open" window status was affected by wind speed, relative humidity, vehicle speed, cloud cover, apparent temperature, day of week, time of day, vehicle type, vehicle age, vehicle color, number of windows, sunroofs, location, and air quality season. Open windows tended to occur less frequently when relative humidity was high, apparent temperature (a parameter incorporating wind chill and heat index) was below 50 degrees F, or the vehicle was relatively new. Although the effects of the identified parameters were relatively weak, they are statistically significant and should be considered by researchers attempting to model vehicle air exchange rates.

Dispersal of seeds from splash-cup plants

NASA Astrophysics Data System (ADS)

Pepper, Rachel

2017-11-01

Splash cup plants disperse their seeds with the help of raindrops. The seeds sit in a small (mm-scale) conical cup and are ejected upon drop impact. The seeds are ejected at velocities up to five times the impact speed of the raindrop, and are dispersed up to 1 m away from the parent plant, which is only a few cm high. Previous work investigating the mechanism of this remarkable dispersal predicted an optimum cup opening angle of around 40°, which matched reasonably well with experiments performed with 3D-printed splash cup models. Those experiments were done with off-center drop impacts on initially empty cups with no seeds. We discuss similar experiments for cups that are not initially empty, but rather contain seed mimics, water, or both seeds and water. For some of these realistic initial states results are strikingly different from empty cups. Connections to theory will also be discussed.

Wind-driven roof turbines: a novel way to improve ventilation for TB infection control in health facilities.

PubMed

Cox, Helen; Escombe, Rod; McDermid, Cheryl; Mtshemla, Yolanda; Spelman, Tim; Azevedo, Virginia; London, Leslie

2012-01-01

Tuberculosis transmission in healthcare facilities contributes significantly to the TB epidemic, particularly in high HIV settings. Although improving ventilation may reduce transmission, there is a lack of evidence to support low-cost practical interventions. We assessed the efficacy of wind-driven roof turbines to achieve recommended ventilation rates, compared to current recommended practices for natural ventilation (opening windows), in primary care clinic rooms in Khayelitsha, South Africa. Room ventilation was assessed (CO₂ gas tracer technique) in 4 rooms where roof turbines and air-intake grates were installed, across three scenarios: turbine, grate and window closed, only window open, and only turbine and grate open, with concurrent wind speed measurement. 332 measurements were conducted over 24 months. For all 4 rooms combined, median air changes per hour (ACH) increased with wind speed quartiles across all scenarios. Higher median ACH were recorded with open roof turbines and grates, compared to open windows across all wind speed quartiles. Ventilation with open turbine and grate exceeded WHO-recommended levels (60 Litres/second/patient) for 95% or more of measurements in 3 of the 4 rooms; 47% in the remaining room, where wind speeds were lower and a smaller diameter turbine was installed. High room ventilation rates, meeting recommended thresholds, may be achieved using wind-driven roof turbines and grates, even at low wind speeds. Roof turbines and air-intake grates are not easily closed by staff, allowing continued ventilation through colder periods. This simple, low-cost technology represents an important addition to our tools for TB infection control.

Wind-Driven Roof Turbines: A Novel Way to Improve Ventilation for TB Infection Control in Health Facilities

PubMed Central

Cox, Helen; Escombe, Rod; McDermid, Cheryl; Mtshemla, Yolanda; Spelman, Tim; Azevedo, Virginia; London, Leslie

2012-01-01

Objective Tuberculosis transmission in healthcare facilities contributes significantly to the TB epidemic, particularly in high HIV settings. Although improving ventilation may reduce transmission, there is a lack of evidence to support low-cost practical interventions. We assessed the efficacy of wind-driven roof turbines to achieve recommended ventilation rates, compared to current recommended practices for natural ventilation (opening windows), in primary care clinic rooms in Khayelitsha, South Africa. Methods Room ventilation was assessed (CO2 gas tracer technique) in 4 rooms where roof turbines and air-intake grates were installed, across three scenarios: turbine, grate and window closed, only window open, and only turbine and grate open, with concurrent wind speed measurement. 332 measurements were conducted over 24 months. Findings For all 4 rooms combined, median air changes per hour (ACH) increased with wind speed quartiles across all scenarios. Higher median ACH were recorded with open roof turbines and grates, compared to open windows across all wind speed quartiles. Ventilation with open turbine and grate exceeded WHO-recommended levels (60 Litres/second/patient) for 95% or more of measurements in 3 of the 4 rooms; 47% in the remaining room, where wind speeds were lower and a smaller diameter turbine was installed. Conclusion High room ventilation rates, meeting recommended thresholds, may be achieved using wind-driven roof turbines and grates, even at low wind speeds. Roof turbines and air-intake grates are not easily closed by staff, allowing continued ventilation through colder periods. This simple, low-cost technology represents an important addition to our tools for TB infection control. PMID:22253742

Vortex ring formation at the open end of a shock tube: A particle image velocimetry study

NASA Astrophysics Data System (ADS)

Arakeri, J. H.; Das, D.; Krothapalli, A.; Lourenco, L.

2004-04-01

The vortex ring generated subsequent to the diffraction of a shock wave from the open end of a shock tube is studied using particle image velocimetry. We examine the early evolution of the compressible vortex ring for three-exit shock Mach numbers, 1.1, 1.2, and 1.3. For the three cases studied, the ring formation is complete at about tUb/D=2, where t is time, Ub is fluid velocity behind shock as it exits the tube and D is tube diameter. Unlike in the case of piston generated incompressible vortex rings where the piston velocity variation with time is usually trapezoidal, in the shock-generated vortex ring case the exit fluid velocity doubles from its initial value Ub before it slowly decays to zero. At the end of the ring formation, its translation speed is observed to be about 0.7 Ub. During initial formation and propagation, a jet-like flow exists behind the vortex ring. The vortex ring detachment from the tailing jet, commonly referred to as pinch-off, is briefly discussed.

Seasat microwave wind and rain observations in severe tropical and midlatitude marine storms

NASA Technical Reports Server (NTRS)

Black, P. G.; Hawkins, J. D.; Gentry, R. C.; Cardone, V. J.

1985-01-01

Initial results of studies concerning Seasat measurements in and around tropical and severe midlatitude cyclones over the open ocean are presented, together with an assessment of their accuracy and usefulness. Complementary measurements of surface wind speed and direction, rainfall rate, and the sea surface temperature obtained with the Seasat-A Satellite Scatterometer (SASS), the Scanning Multichannel Microwave Radiometer (SMMR), and the Seasat SAR are analyzed. The Seasat data for the Hurrricanes Fico, Ella, and Greta and the QE II storm are compared with data obtained from aircraft, buoys, and ships. It is shown that the SASS-derived wind speeds are accurate to within 10 percent, and the directions are accurate to within 20 percent. In general, the SASS estimates tend to measure light winds too high and intense winds too low. The errors of the SMMR-derived measurements of the winds in hurricanes tend to be higher than those of the SASS-derived measurements.

Using a thermistor flowmeter with attached video camera for monitoring sponge excurrent speed and oscular behaviour

PubMed Central

Jorgensen, Damien; Webster, Nicole S.; Pineda, Mari-Carmen; Duckworth, Alan

2016-01-01

A digital, four-channel thermistor flowmeter integrated with time-lapse cameras was developed as an experimental tool for measuring pumping rates in marine sponges, particularly those with small excurrent openings (oscula). Combining flowmeters with time-lapse imagery yielded valuable insights into the contractile behaviour of oscula in Cliona orientalis. Osculum cross-sectional area (OSA) was positively correlated to measured excurrent speeds (ES), indicating that sponge pumping and osculum contraction are coordinated behaviours. Both OSA and ES were positively correlated to pumping rate (Q). Diel trends in pumping activity and osculum contraction were also observed, with sponges increasing their pumping activity to peak at midday and decreasing pumping and contracting oscula at night. Short-term elevation of the suspended sediment concentration (SSC) within the seawater initially decreased pumping rates by up to 90%, ultimately resulting in closure of the oscula and cessation of pumping. PMID:27994973

Kinematic measurements of the vocal-fold displacement waveform in typical children and adult populations: quantification of high-speed endoscopic videos.

PubMed

Patel, Rita; Donohue, Kevin D; Unnikrishnan, Harikrishnan; Kryscio, Richard J

2015-04-01

This article presents a quantitative method for assessing instantaneous and average lateral vocal-fold motion from high-speed digital imaging, with a focus on developmental changes in vocal-fold kinematics during childhood. Vocal-fold vibrations were analyzed for 28 children (aged 5-11 years) and 28 adults (aged 21-45 years) without voice disorders. The following kinematic features were analyzed from the vocal-fold displacement waveforms: relative velocity-based features (normalized average and peak opening and closing velocities), relative acceleration-based features (normalized peak opening and closing accelerations), speed quotient, and normalized peak displacement. Children exhibited significantly larger normalized peak displacements, normalized average and peak opening velocities, normalized average and peak closing velocities, peak opening and closing accelerations, and speed quotient compared to adult women. Values of normalized average closing velocity and speed quotient were higher in children compared to adult men. When compared to adult men, developing children typically have higher estimates of kinematic features related to normalized displacement and its derivatives. In most cases, the kinematic features of children are closer to those of adult men than adult women. Even though boys experience greater changes in glottal length and pitch as they mature, results indicate that girls experience greater changes in kinematic features compared to boys.

Transient behavior of a flare-associated solar wind. I - Gas dynamics in a radial open field region

NASA Technical Reports Server (NTRS)

Nagai, F.

1984-01-01

A numerical investigation is conducted into the way in which a solar wind model initially satisfying both steady state and energy balance conditions is disturbed and deformed, under the assumption of heating that correspoonds to the energy release of solar flares of an importance value of approximately 1 which occur in radial open field regions. Flare-associated solar wind transient behavior is modeled for 1-8 solar radii. The coronal temperature around the heat source region rises, and a large thermal conductive flux flows inward to the chromosphere and outward to interplanetary space along field lines. The speed of the front of expanding chromospheric material generated by the impingement of the conduction front on the upper chromosphere exceeds the local sound velocity in a few minutes and eventually exceeds 100 million cm/sec.

A pilot clinical trial on a Variable Automated Speed and Sensing Treadmill (VASST) for hemiparetic gait rehabilitation in stroke patients.

PubMed

Chua, Karen S G; Chee, Johnny; Wong, Chin J; Lim, Pang H; Lim, Wei S; Hoo, Chuan M; Ong, Wai S; Shen, Mira L; Yu, Wei S

2015-01-01

Impairments in walking speed and capacity are common problems after stroke which may benefit from treadmill training. However, standard treadmills, are unable to adapt to the slower walking speeds of stroke survivors and are unable to automate training progression. This study tests a Variable Automated Speed and Sensing Treadmill (VASST) using a standard clinical protocol. VASST is a semi-automated treadmill with multiple sensors and micro controllers, including wireless control to reposition a fall-prevention harness, variable pre-programmed exercise parameters and laser beam foot sensors positioned on the belt to detect subject's foot positions. An open-label study with assessor blinding was conducted in 10 community-dwelling chronic hemiplegic patients who could ambulate at least 0.1 m/s. Interventions included physiotherapist-supervised training on VASST for 60 min three times per week for 4 weeks (total 12 h). Outcome measures of gait speed, quantity, balance, and adverse events were assessed at baseline, 2, 4, and 8 weeks. Ten subjects (8 males, mean age 55.5 years, 2.1 years post stroke) completed VASST training. Mean 10-m walk test speed was 0.69 m/s (SD = 0.29) and mean 6-min walk test distance was 178.3 m (84.0). After 4 weeks of training, 70% had significant positive gains in gait speed (0.06 m/s, SD = 0.08 m/s, P = 0.037); and 90% improved in walking distance. (54.3 m, SD = 30.9 m, P = 0.005). There were no adverse events. This preliminary study demonstrates the initial feasibility and short-term efficacy of VASST for walking speed and distance for people with chronic post-stroke hemiplegia.

Effect of Initial Mixture Temperature on Flame Speed of Methane-Air, Propane-Air, and Ethylene-Air Mixtures

NASA Technical Reports Server (NTRS)

Dugger, Gordon L

1952-01-01

Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene. Empirical equations were determined for maximum flame speed as a function of initial temperature over the temperature range covered for each fuel. The observed effect of temperature on flame speed for each of the fuels was reasonably well predicted by either the thermal theory as presented by Semenov or the square-root law of Tanford and Pease.

Speed behaviour in work zone crossovers. A driving simulator study.

PubMed

Domenichini, Lorenzo; La Torre, Francesca; Branzi, Valentina; Nocentini, Alessandro

2017-01-01

Reductions in speed and, more critically, in speed variability between vehicles are considered an important factor to reduce crash risk in work zones. This study was designed to evaluate in a virtual environment the drivers' behaviour in response to nine different configurations of a motorway crossover work zone. Specifically, the speed behaviour through a typical crossover layout, designed in accordance with the Italian Ministerial Decree 10 July 2002, was compared with that of eight alternative configurations which differ in some characteristics such as the sequence of speed limits, the median opening width and the lane width. The influence of variable message signs, of channelizing devices and of perceptual treatments based on Human Factor principles were also tested. Forty-two participants drove in driving simulator scenarios while data on their speeds and decelerations were collected. The results indicated that drivers' speeds are always higher than the temporary posted speed limits for all configurations and that speeds decreases significantly only within the by-passes. However the implementation of higher speed limits, together with a wider median opening and taller channelization devices led to a greater homogeneity of the speeds adopted by the drivers. The presence of perceptual measures generally induced both the greatest homogenization of speeds and the largest reductions in mean speed values. Copyright © 2016 Elsevier Ltd. All rights reserved.

78 FR 32007 - Environmental Impact Statement for Tulsa-Oklahoma City Passenger Rail Corridor, Oklahoma, Lincoln...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-28

... Environmental Policy Act of 1969 (NEPA) for the State of Oklahoma High-Speed Rail Initiative: Tulsa--Oklahoma... South Central High Speed Rail Corridor and is a federally-designated high-speed rail (HSR) corridor...-Speed Rail Initiative: Tulsa--Oklahoma City Passenger Rail Corridor Investment Plan. The proposed route...

Continuous-flow cardiac assistance: effects on aortic valve function in a mock loop.

PubMed

Tuzun, Egemen; Rutten, Marcel; Dat, Marco; van de Vosse, Frans; Kadipasaoglu, Cihan; de Mol, Bas

2011-12-01

As the use of left ventricular assist devices (LVADs) to treat end-stage heart failure has become more widespread, leaflet fusion--with resul-tant aortic regurgitation--has been observed more frequently. To quantitatively assess the effects of nonpulsatile flow on aortic valve function, we tested a continuous-flow LVAD in a mock circulatory system (MCS) with an interposed valve. To mimic the hemodynamic characteristics of LVAD patients, we utilized an MCS in which a Jarvik 2000 LVAD was positioned at the base of a servomotor-operated piston pump (left ventricular chamber). We operated the LVAD at 8000 to 12,000 rpm, changing the speed in 1000-rpm increments. At each speed, we first varied the outflow resistance at a constant stroke volume, then varied the stroke volume at a constant outflow resistance. We measured the left ventricular pressure, aortic pressure, pump flow, and total flow, and used these values to compute the change, if any, in the aortic duty cycle (aortic valve open time) and transvalvular aortic pressure loads. Validation of the MCS was demonstrated by the simulation of physiologic pressure and flow waveforms. At increasing LVAD speeds, the mean aortic pressure load steadily increased, while the aortic duty cycle steadily decreased. Changes were consistent for each MCS experimental setting, despite variations in stroke volume and outflow resistance. Increased LVAD flow results in an impaired aortic valve-open time due to a pressure overload above the aortic valve. Such an overload may initiate structural changes, causing aortic leaflet fusion and/or regurgitation. Copyright © 2011 Elsevier Inc. All rights reserved.

The relationship between initial route of heroin administration and speed of transition to daily heroin use.

PubMed

Hines, Lindsey A; Lynskey, Michael; Morley, Katherine I; Griffiths, Paul; Gossop, Michael; Powis, Beverly; Strang, John

2017-09-01

The effect of heroin administration route on speed of transition to regular use is unknown. This paper aims to determine whether the speed of transition from initiation of heroin use to daily heroin use differs by route of administration (injecting, chasing/inhaling or snorting). Privileged access interviewer survey of purposively selected sample of 395 current people who use heroin (both in and not in treatment) in London, UK (historical sample from 1991). Data on age and year of initiation, time from initiation to daily use and routes of administration were collected by means of a structured questionnaire. Generalised ordered logistic models were used to test the relationship between route of initial administration of heroin and speed of transition to daily heroin use. Analyses were adjusted for gender, ethnicity, daily use of other drug(s) at time of initiation, year of initiation and treatment status at interview. After adjustment, participants whose initial administration route was injecting had a 4.71 (95% confidence interval 1.34-16.5) increase in likelihood of progressing to daily use within 1-3 weeks of initiation, compared to those whose initial administration route was non-injecting. The speed of transition from first use to daily heroin use is faster if the individual injects heroin at initiation of use. Those who initiate heroin use through injecting have a shorter time frame for intervention before drug use escalation. [Hines LA, Lynskey M, Morley KI, Griffiths P, Gossop M, Powis B, Strang J. The relationship between initial route of heroin administration and speed of transition to daily heroin use. Drug Alcohol Rev 2017;00:000-000]. © 2017 Australasian Professional Society on Alcohol and other Drugs.

Kinematic Measurements of the Vocal-Fold Displacement Waveform in Typical Children and Adult Populations: Quantification of High-Speed Endoscopic Videos

PubMed Central

Donohue, Kevin D.; Unnikrishnan, Harikrishnan; Kryscio, Richard J.

2015-01-01

Purpose This article presents a quantitative method for assessing instantaneous and average lateral vocal-fold motion from high-speed digital imaging, with a focus on developmental changes in vocal-fold kinematics during childhood. Method Vocal-fold vibrations were analyzed for 28 children (aged 5–11 years) and 28 adults (aged 21–45 years) without voice disorders. The following kinematic features were analyzed from the vocal-fold displacement waveforms: relative velocity-based features (normalized average and peak opening and closing velocities), relative acceleration-based features (normalized peak opening and closing accelerations), speed quotient, and normalized peak displacement. Results Children exhibited significantly larger normalized peak displacements, normalized average and peak opening velocities, normalized average and peak closing velocities, peak opening and closing accelerations, and speed quotient compared to adult women. Values of normalized average closing velocity and speed quotient were higher in children compared to adult men. Conclusions When compared to adult men, developing children typically have higher estimates of kinematic features related to normalized displacement and its derivatives. In most cases, the kinematic features of children are closer to those of adult men than adult women. Even though boys experience greater changes in glottal length and pitch as they mature, results indicate that girls experience greater changes in kinematic features compared to boys. PMID:25652615

Wind energy input into the upper ocean over a lengthening open water season

NASA Astrophysics Data System (ADS)

Mahoney, A. R.; Rolph, R.; Walsh, J. E.

2017-12-01

Wind energy input into the ocean has important consequences for upper ocean mixing, heat and gas exchange, and air-sea momentum transfer. In the Arctic, the open water season is increasing and extending further into the fall storm season, allowing for more wind energy input into the water column. The rate at which the delayed freeze-up timing extends into fall storm season is an important metric to evaluate because the expanding overlap between the open water period and storm season could contribute a significant amount of wind energy into the water column in a relatively short period of time. We have shown that time-integrated wind speeds over open water in the Chukchi Sea and southern Beaufort region have increased since 1979 through 2014. An integrated wind energy input value is calculated for each year in this domain over the open water season, as well as for periods over partial concentrations of ice cover. Spatial variation of this integrated wind energy is shown along the Alaskan coastline, which can have implications for different rates of coastal erosion. Spatial correlation between average wind speed over open water and open water season length from 1979-2014 show positive values in the southern Beaufort, but negative values in the northern Chukchi. This suggests possible differences in the role of the ocean on open water season length depending on region. We speculate that the warm Pacific water outflow plays a more dominant role in extending the open water season length in the northern Chukchi when compared to the southern Beaufort, and might help explain why we can show there is a relatively longer open water season length there. The negative and positive correlations in wind speeds over open water and open water season length might also be explained by oceanic changes tending to operate on longer timescales than the atmosphere. Seasonal timescales of wind events such as regional differences in overlap of the extended open water season due to regional differences in delayed freeze-up into the fall storm season are also investigated. In addition, we have shown that the increased integrated wind energy input over open water values are more a result of the increased open water season length, rather than the increase in wind speeds over open water.

Parameter estimation for a cohesive sediment transport model by assimilating satellite observations in the Hangzhou Bay: Temporal variations and spatial distributions

NASA Astrophysics Data System (ADS)

Wang, Daosheng; Zhang, Jicai; He, Xianqiang; Chu, Dongdong; Lv, Xianqing; Wang, Ya Ping; Yang, Yang; Fan, Daidu; Gao, Shu

2018-01-01

Model parameters in the suspended cohesive sediment transport models are critical for the accurate simulation of suspended sediment concentrations (SSCs). Difficulties in estimating the model parameters still prevent numerical modeling of the sediment transport from achieving a high level of predictability. Based on a three-dimensional cohesive sediment transport model and its adjoint model, the satellite remote sensing data of SSCs during both spring tide and neap tide, retrieved from Geostationary Ocean Color Imager (GOCI), are assimilated to synchronously estimate four spatially and temporally varying parameters in the Hangzhou Bay in China, including settling velocity, resuspension rate, inflow open boundary conditions and initial conditions. After data assimilation, the model performance is significantly improved. Through several sensitivity experiments, the spatial and temporal variation tendencies of the estimated model parameters are verified to be robust and not affected by model settings. The pattern for the variations of the estimated parameters is analyzed and summarized. The temporal variations and spatial distributions of the estimated settling velocity are negatively correlated with current speed, which can be explained using the combination of flocculation process and Stokes' law. The temporal variations and spatial distributions of the estimated resuspension rate are also negatively correlated with current speed, which are related to the grain size of the seabed sediments under different current velocities. Besides, the estimated inflow open boundary conditions reach the local maximum values near the low water slack conditions and the estimated initial conditions are negatively correlated with water depth, which is consistent with the general understanding. The relationships between the estimated parameters and the hydrodynamic fields can be suggestive for improving the parameterization in cohesive sediment transport models.

Holographic Jet Shapes and their Evolution in Strongly Coupled Plasma

NASA Astrophysics Data System (ADS)

Brewer, Jasmine; Rajagopal, Krishna; Sadofyev, Andrey; van der Schee, Wilke

2017-11-01

Recently our group analyzed how the probability distribution for the jet opening angle is modified in an ensemble of jets that has propagated through an expanding cooling droplet of plasma [K. Rajagopal, A. V. Sadofyev, W. van der Schee, Phys. Rev. Lett. 116 (2016) 211603]. Each jet in the ensemble is represented holographically by a string in the dual 4+1- dimensional gravitational theory with the distribution of initial energies and opening angles in the ensemble given by perturbative QCD. In [K. Rajagopal, A. V. Sadofyev, W. van der Schee, Phys. Rev. Lett. 116 (2016) 211603], the full string dynamics were approximated by assuming that the string moves at the speed of light. We are now able to analyze the full string dynamics for a range of possible initial conditions, giving us access to the dynamics of holographic jets just after their creation. The nullification timescale and the features of the string when it has nullified are all results of the string evolution. This emboldens us to analyze the full jet shape modification, rather than just the opening angle modification of each jet in the ensemble as in [K. Rajagopal, A. V. Sadofyev, W. van der Schee, Phys. Rev. Lett. 116 (2016) 211603]. We find the result that the jet shape scales with the opening angle at any particular energy. We construct an ensemble of dijets with energies and energy asymmetry distributions taken from events in proton-proton collisions, opening angle distribution as in [K. Rajagopal, A. V. Sadofyev, W. van der Schee, Phys. Rev. Lett. 116 (2016) 211603], and jet shape taken from proton-proton collisions and scaled according to our result. We study how these observables are modified after we send the ensemble of dijets through the strongly-coupled plasma.

Dynamic calibration of fast-response probes in low-pressure shock tubes

NASA Astrophysics Data System (ADS)

Persico, G.; Gaetani, P.; Guardone, A.

2005-09-01

Shock tube flows resulting from the incomplete burst of the diaphragm are investigated in connection with the dynamic calibration of fast-response pressure probes. As a result of the partial opening of the diaphragm, pressure disturbances are observed past the shock wave and the measured total pressure profile deviates from the envisaged step signal required by the calibration process. Pressure oscillations are generated as the initially normal shock wave diffracts from the diaphragm's orifice and reflects on the shock tube walls, with the lowest local frequency roughly equal to the ratio of the sound speed in the perturbed region to the shock tube diameter. The energy integral of the perturbations decreases with increasing distance from the diaphragm, as the diffracted leading shock and downwind reflections coalesce into a single normal shock. A procedure is proposed to calibrate fast-response pressure probes downwind of a partially opened shock tube diaphragm.

Steady hydromagnetic flows in open magnetic fields. I - A class of analytic solutions. [for stellar winds

NASA Technical Reports Server (NTRS)

Low, B. C.; Tsinganos, K.

1986-01-01

In the case of an establishment of theoretical models of the hydromagnetic solar wind, the inclusion of the effects of the magnetic field in the solar wind makes it extremely dificult to solve the mathematical problem. This paper has the objective to present a set of particular analytic solutions. The general formulation of Tsinganos (1982) is used to identify a class of analytic solutions to the equations of steady hydromagnetic flows in spherical coordinates. Flow in an open magnetic field are studied, taking into account the problem in dimensionless form, the special case of radial flows with alpha = 0, general radial flows, illustrative examples for flows in which alpha is not equal to 0, a parametric study of nonradial flows in which alpha is not equal to zero, variations in the parameter nu, and variations in the initial speed eta.

Ingenious Snake: An Adaptive Multi-Class Contours Extraction

NASA Astrophysics Data System (ADS)

Li, Baolin; Zhou, Shoujun

2018-04-01

Active contour model (ACM) plays an important role in computer vision and medical image application. The traditional ACMs were used to extract single-class of object contours. While, simultaneous extraction of multi-class of interesting contours (i.e., various contours with closed- or open-ended) have not been solved so far. Therefore, a novel ACM model named “Ingenious Snake” is proposed to adaptively extract these interesting contours. In the first place, the ridge-points are extracted based on the local phase measurement of gradient vector flow field; the consequential ridgelines initialization are automated with high speed. Secondly, the contours’ deformation and evolvement are implemented with the ingenious snake. In the experiments, the result from initialization, deformation and evolvement are compared with the existing methods. The quantitative evaluation of the structure extraction is satisfying with respect of effectiveness and accuracy.

Students’ Spatial Ability through Open-Ended Approach Aided by Cabri 3D

NASA Astrophysics Data System (ADS)

Priatna, N.

2017-09-01

The use of computer software such as Cabri 3D for learning activities is very unlimited. Students can adjust their learning speed according to their level of ability. Open-ended approach strongly supports the use of computer software in learning, because the goal of open-ended learning is to help developing creative activities and mathematical mindset of students through problem solving simultaneously. In other words, creative activities and mathematical mindset of students should be developed as much as possible in accordance with the ability of spatial ability of each student. Spatial ability is the ability of students in constructing and representing geometry models. This study aims to determine the improvement of spatial ability of junior high school students who obtained learning with open-ended approach aided by Cabri 3D. It adopted a quasi-experimental method with the non-randomized control group pretest-posttest design and the 2×3 factorial model. The instrument of the study is spatial ability test. Based on analysis of the data, it is found that the improvement of spatial ability of students who received open-ended learning aided by Cabri 3D was greater than students who received expository learning, both as a whole and based on the categories of students’ initial mathematical ability.

Speed of Sound versus Temperature Using PVC Pipes Open at Both Ends

ERIC Educational Resources Information Center

Bacon, Michael E.

2012-01-01

In this paper we investigate the speed of sound in air as a function of temperature using a simple and inexpensive apparatus. For this experiment it is essential that the appropriate end corrections be taken into account. In a recent paper the end corrections for 2-in i.d. (5.04-cm) PVC pipes open at both ends were investigated. The air column…

Big data, open science and the brain: lessons learned from genomics.

PubMed

Choudhury, Suparna; Fishman, Jennifer R; McGowan, Michelle L; Juengst, Eric T

2014-01-01

The BRAIN Initiative aims to break new ground in the scale and speed of data collection in neuroscience, requiring tools to handle data in the magnitude of yottabytes (10(24)). The scale, investment and organization of it are being compared to the Human Genome Project (HGP), which has exemplified "big science" for biology. In line with the trend towards Big Data in genomic research, the promise of the BRAIN Initiative, as well as the European Human Brain Project, rests on the possibility to amass vast quantities of data to model the complex interactions between the brain and behavior and inform the diagnosis and prevention of neurological disorders and psychiatric disease. Advocates of this "data driven" paradigm in neuroscience argue that harnessing the large quantities of data generated across laboratories worldwide has numerous methodological, ethical and economic advantages, but it requires the neuroscience community to adopt a culture of data sharing and open access to benefit from them. In this article, we examine the rationale for data sharing among advocates and briefly exemplify these in terms of new "open neuroscience" projects. Then, drawing on the frequently invoked model of data sharing in genomics, we go on to demonstrate the complexities of data sharing, shedding light on the sociological and ethical challenges within the realms of institutions, researchers and participants, namely dilemmas around public/private interests in data, (lack of) motivation to share in the academic community, and potential loss of participant anonymity. Our paper serves to highlight some foreseeable tensions around data sharing relevant to the emergent "open neuroscience" movement.

Performance analysis of air-water quantum key distribution with an irregular sea surface

NASA Astrophysics Data System (ADS)

Xu, Hua-bin; Zhou, Yuan-yuan; Zhou, Xue-jun; Wang, Lian

2018-05-01

In the air-water quantum key distribution (QKD), the irregular sea surface has some influence on the photon polarization state. The wind is considered as the main factor causing the irregularity, so the model of irregular sea surface based on the wind speed is adopted. The relationships of the quantum bit error rate with the wind speed and the initial incident angle are simulated. Therefore, the maximum secure transmission depth of QKD is confirmed, and the limitation of the wind speed and the initial incident angle is determined. The simulation results show that when the wind speed and the initial incident angle increase, the performance of QKD will fall down. Under the intercept-resend attack condition, the maximum safe transmission depth of QKD is up to 105 m. To realize safe communications in the safe diving depth of submarines (100 m), the initial incident angle is requested to be not exceeding 26°, and with the initial incident angle increased, the limitation of wind speed is decreased.

Forest impact estimated with NOAA AVHRR and landsat TM data related to an empirical hurricane wind-field distribution

USGS Publications Warehouse

Ramsey, Elijah W.; Hodgson, M.E.; Sapkota, S.K.; Nelson, G.A.

2001-01-01

An empirical model was used to relate forest type and hurricane-impact distribution with wind speed and duration to explain the variation of hurricane damage among forest types along the Atchafalaya River basin of coastal Louisiana. Forest-type distribution was derived from Landsat Thematic Mapper image data, hurricane-impact distribution from a suite of transformed advanced very high resolution radiometer images, and wind speed and duration from a wind-field model. The empirical model explained 73%, 84%, and 87% of the impact variances for open, hardwood, and cypress-tupelo forests, respectively. These results showed that the estimated impact for each forest type was highly related to the duration and speed of extreme winds associated with Hurricane Andrew in 1992. The wind-field model projected that the highest wind speeds were in the southern basin, dominated by cypress-tupelo and open forests, while lower wind speeds were in the northern basin, dominated by hardwood forests. This evidence could explain why, on average, the impact to cypress-tupelos was more severe than to hardwoods, even though cypress-tupelos are less susceptible to wind damage. Further, examination of the relative importance of wind speed in explaining the impact severity to each forest type showed that the impact to hardwood forests was mainly related to tropical-depression to tropical-storm force wind speeds. Impacts to cypress-tupelo and open forests (a mixture of willows and cypress-tupelo) were broadly related to tropical-storm force wind speeds and by wind speeds near and somewhat in excess of hurricane force. Decoupling the importance of duration from speed in explaining the impact severity to the forests could not be fully realized. Most evidence, however, hinted that impact severity was positively related to higher durations at critical wind speeds. Wind-speed intervals, which were important in explaining the impact severity on hardwoods, showed that higher durations, but not the highest wind speeds, were concentrated in the northern basin, dominated by hardwoods. The extreme impacts associated with the cypress-tupelo forests in the southeast corner of the basin intersected the highest durations as well as the highest wind speeds. ?? 2001 Published by Elsevier Science Inc.

33. Three bolts on railing outside control house on north ...

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

33. Three bolts on railing outside control house on north tower, one bolt on first handrail post of the north span (bridge is in the open position). As the bridge opens or closes the single bolt on the handrail post moves past the three stationary bolts. This system is used by the bridge operator to judge speed and position of the north span as it opens or closes. Based on these bolts movement of the north span is speeded up or slowed down and the brakes applied during the opening and closing process. View facing east. - Henry Ford Bridge, Spanning Cerritos Channel, Los Angeles-Long Beach Harbor, Los Angeles, Los Angeles County, CA

The scaling issue: scientific opportunities

NASA Astrophysics Data System (ADS)

Orbach, Raymond L.

2009-07-01

A brief history of the Leadership Computing Facility (LCF) initiative is presented, along with the importance of SciDAC to the initiative. The initiative led to the initiation of the Innovative and Novel Computational Impact on Theory and Experiment program (INCITE), open to all researchers in the US and abroad, and based solely on scientific merit through peer review, awarding sizeable allocations (typically millions of processor-hours per project). The development of the nation's LCFs has enabled available INCITE processor-hours to double roughly every eight months since its inception in 2004. The 'top ten' LCF accomplishments in 2009 illustrate the breadth of the scientific program, while the 75 million processor hours allocated to American business since 2006 highlight INCITE contributions to US competitiveness. The extrapolation of INCITE processor hours into the future brings new possibilities for many 'classic' scaling problems. Complex systems and atomic displacements to cracks are but two examples. However, even with increasing computational speeds, the development of theory, numerical representations, algorithms, and efficient implementation are required for substantial success, exhibiting the crucial role that SciDAC will play.

Shaft seal assembly and method

NASA Technical Reports Server (NTRS)

Keba, John E. (Inventor)

2007-01-01

A pressure-actuated shaft seal assembly and associated method for controlling the flow of fluid adjacent a rotatable shaft are provided. The seal assembly includes one or more seal members that can be adjusted between open and closed positions, for example, according to the rotational speed of the shaft. For example, the seal member can be configured to be adjusted according to a radial pressure differential in a fluid that varies with the rotational speed of the shaft. In addition, in the closed position, each seal member can contact a rotatable member connected to the shaft to form a seal with the rotatable member and prevent fluid from flowing through the assembly. Thus, the seal can be closed at low speeds of operation and opened at high speeds of operation, thereby reducing the heat and wear in the seal assembly while maintaining a sufficient seal during all speeds of operation.

Fast particle ejection by a growing laser-induced bubble

NASA Astrophysics Data System (ADS)

Zuo, Zhigang; Wu, Shengji; Stone, Howard; Liu, Shuhong

2017-11-01

We document experimentally four different interactions of a laser-induced bubble and a free-settling particle, with different combinations of the geometric and physical parameters of the system. In particular, we also discover the high-speed ejection of the particle, and a cavity behind the particle, in cases when initially the particle is in very close proximity to the bubble. These observations offer new insights into the causal mechanism for the enhanced cavitation erosion in silt-laden water. The work was supported by the National Natural Science Foundation of China (No. 51476083) and the open research project of State Key Laboratory of Hydroscience and Engineering.

Effects of Vocal Fold Nodules on Glottal Cycle Measurements Derived from High-Speed Videoendoscopy in Children

PubMed Central

2016-01-01

The goal of this study is to quantify the effects of vocal fold nodules on vibratory motion in children using high-speed videoendoscopy. Differences in vibratory motion were evaluated in 20 children with vocal fold nodules (5–11 years) and 20 age and gender matched typically developing children (5–11 years) during sustained phonation at typical pitch and loudness. Normalized kinematic features of vocal fold displacements from the mid-membranous vocal fold point were extracted from the steady-state high-speed video. A total of 12 kinematic features representing spatial and temporal characteristics of vibratory motion were calculated. Average values and standard deviations (cycle-to-cycle variability) of the following kinematic features were computed: normalized peak displacement, normalized average opening velocity, normalized average closing velocity, normalized peak closing velocity, speed quotient, and open quotient. Group differences between children with and without vocal fold nodules were statistically investigated. While a moderate effect size was observed for the spatial feature of speed quotient, and the temporal feature of normalized average closing velocity in children with nodules compared to vocally normal children, none of the features were statistically significant between the groups after Bonferroni correction. The kinematic analysis of the mid-membranous vocal fold displacement revealed that children with nodules primarily differ from typically developing children in closing phase kinematics of the glottal cycle, whereas the opening phase kinematics are similar. Higher speed quotients and similar opening phase velocities suggest greater relative forces are acting on vocal fold in the closing phase. These findings suggest that future large-scale studies should focus on spatial and temporal features related to the closing phase of the glottal cycle for differentiating the kinematics of children with and without vocal fold nodules. PMID:27124157

IN VITRO FLOW ANALYSIS OF NOVEL DOUBLE-CUTTING, OPEN-PORT, ULTRAHIGH-SPEED VITRECTOMY SYSTEMS.

PubMed

Zehetner, Claus; Moelgg, Marion; Bechrakis, Emmanouil; Linhart, Caroline; Bechrakis, Nikolaos E

2017-10-09

To analyze the performance and flow characteristics of novel double-cutting, open-port, 23-, 25-, and 27-gauge ultrahigh-speed vitrectomy systems. In vitro fluidic measurements were performed to assess the volumetric aspiration profiles of several vitrectomy systems in basic salt solution and egg white. Double-cutting open-port vitrectomy probes delivered stable aspiration flow rates that were less prone to flow variation affected by the cutting speed. Increase in cutting frequency to the maximum level resulted in flow reduction of less than 10% (0.0%-9.5%). Commercially available 23-, 25-, and 27-G double-cutting probes exhibited higher egg-white and basic salt solution flow rates at all evaluated cut rates, with aspirational efficiencies being 1.1 to 2.9 times the flow rates of standard single-blade vitrectomy probes of the same caliber at the maximum preset vacuum. The highest relative differences were observed at faster cut rates. The newly introduced double-cutting open-port vitrectomy probes delivered stable aspiration flow rates that were less prone to flow variation affected by the cutting speed. The fluidic principle of constant flow even at the highest cut rates and low vacuum levels might impact surgical strategies, especially when performing manipulations close to the retina.

Diaphragm opening effects on shock wave formation and acceleration in a rectangular cross section channel

NASA Astrophysics Data System (ADS)

Pakdaman, S. A.; Garcia, M.; Teh, E.; Lincoln, D.; Trivedi, M.; Alves, M.; Johansen, C.

2016-11-01

Shock wave formation and acceleration in a high-aspect ratio cross section shock tube were studied experimentally and numerically. The relative importance of geometric effects and diaphragm opening time on shock formation are assessed. The diaphragm opening time was controlled through the use of slit-type (fast opening time) and petal-type (slow opening time) diaphragms. A novel method of fabricating the petal-type diaphragms, which results in a consistent burst pressure and symmetric opening without fragmentation, is presented. High-speed schlieren photography was used to visualize the unsteady propagation of the lead shock wave and trailing gas dynamic structures. Surface-mounted pressure sensors were used to capture the spatial and temporal development of the pressure field. Unsteady Reynolds-Averaged Navier-Stokes simulation predictions using the shear-stress-transport turbulence model are compared to the experimental data. Simulation results are used to explain the presence of high-frequency pressure oscillations observed experimentally in the driver section as well as the cause of the initial acceleration and subsequent rapid decay of shock velocity measured along the top and bottom channel surfaces. A one-dimensional theoretical model predicting the effect of the finite opening time of the diaphragm on the rate of driver depressurization and shock acceleration is proposed. The model removes the large amount of empiricism that accompanies existing models published in the literature. Model accuracy is assessed through comparisons with experiments and simulations. Limitations of and potential improvements in the model are discussed.

Comprehensive Oculomotor Behavioral Response Assessment (COBRA)

NASA Technical Reports Server (NTRS)

Stone, Leland S. (Inventor); Liston, Dorion B. (Inventor)

2017-01-01

An eye movement-based methodology and assessment tool may be used to quantify many aspects of human dynamic visual processing using a relatively simple and short oculomotor task, noninvasive video-based eye tracking, and validated oculometric analysis techniques. By examining the eye movement responses to a task including a radially-organized appropriately randomized sequence of Rashbass-like step-ramp pursuit-tracking trials, distinct performance measurements may be generated that may be associated with, for example, pursuit initiation (e.g., latency and open-loop pursuit acceleration), steady-state tracking (e.g., gain, catch-up saccade amplitude, and the proportion of the steady-state response consisting of smooth movement), direction tuning (e.g., oblique effect amplitude, horizontal-vertical asymmetry, and direction noise), and speed tuning (e.g., speed responsiveness and noise). This quantitative approach may provide fast and results (e.g., a multi-dimensional set of oculometrics and a single scalar impairment index) that can be interpreted by one without a high degree of scientific sophistication or extensive training.

Big-BOE: Fusing Spanish Official Gazette with Big Data Technology.

PubMed

Basanta-Val, Pablo; Sánchez-Fernández, Luis

2018-06-01

The proliferation of new data sources, stemmed from the adoption of open-data schemes, in combination with an increasing computing capacity causes the inception of new type of analytics that process Internet of things with low-cost engines to speed up data processing using parallel computing. In this context, the article presents an initiative, called BIG-Boletín Oficial del Estado (BOE), designed to process the Spanish official government gazette (BOE) with state-of-the-art processing engines, to reduce computation time and to offer additional speed up for big data analysts. The goal of including a big data infrastructure is to be able to process different BOE documents in parallel with specific analytics, to search for several issues in different documents. The application infrastructure processing engine is described from an architectural perspective and from performance, showing evidence on how this type of infrastructure improves the performance of different types of simple analytics as several machines cooperate.

Design and Performance Improvements of the Prototype Open Core Flywheel Energy Storage System

NASA Technical Reports Server (NTRS)

Pang, D.; Anand, D. K. (Editor); Kirk, J. A. (Editor)

1996-01-01

A prototype magnetically suspended composite flywheel energy storage (FES) system is operating at the University of Maryland. This system, designed for spacecraft applications, incorporates recent advances in the technologies of composite materials, magnetic suspension, and permanent magnet brushless motor/generator. The current system is referred to as an Open Core Composite Flywheel (OCCF) energy storage system. This paper will present design improvements for enhanced and robust performance. Initially, when the OCCF prototype was spun above its first critical frequency of 4,500 RPM, the rotor movement would exceed the space available in the magnetic suspension gap and touchdown on the backup mechanical bearings would occur. On some occasions it was observed that, after touchdown, the rotor was unable to re-suspend as the speed decreased. Additionally, it was observed that the rotor would exhibit unstable oscillations when the control system was initially turned on. Our analysis suggested that the following problems existed: (1) The linear operating range of the magnetic bearings was limited due to electrical and magnetic saturation; (2) The inductance of the magnetic bearings was affecting the transient response of the system; (3) The flywheel was confined to a small movement because mechanical components could not be held to a tight tolerance; and (4) The location of the touchdown bearing magnifies the motion at the pole faces of the magnetic bearings when the linear range is crucial. In order to correct these problems an improved design of the flywheel energy storage system was undertaken. The magnetic bearings were re-designed to achieve a large linear operating range and to withstand load disturbances of at least 1 g. The external position transducers were replaced by a unique design which were resistant to magnetic field noise and allowed cancellation of the radial growth of the flywheel at high speeds. A central rod was utilized to ensure the concentricity of the magnetic bearings, the motor/generator, and the mechanical touchdown bearings. In addition, the mechanical touchdown bearings were placed at two ends of the magnetic bearing stack to restrict the motion at pole faces. A composite flywheel was made using a multi-ring interference assembled design for a high specific energy density. To achieve a higher speed and better efficiency, a permanent magnet DC brushless motor was specially designed and fabricated. A vacuum enclosure was constructed to eliminate windage losses for testing at high speeds. With the new improvements the OCCF system was tested to 20,000 RPM with a total stored energy of 15.9 WH and an angular momentum of 54.8 N-m-s (40.4 lb-ft-s). Motor current limitation, caused by power loss in the magnetic bearings, was identified as causing the limit in upper operating speed.

Dust coagulation and magnetic field strength in a planet-induced gap subject to MRI turbulence

NASA Astrophysics Data System (ADS)

Carballido, Augusto; Matthews, Lorin; Hyde, Truell

2017-01-01

We investigate the coagulation of dust particles in and around a gap opened by a Jupiter-mass planet. To this end, we carry out a high-resolution magnetohydrodynamic (MHD) simulation of the gap environment, which is turbulent due to the magneto rotational instability. From the MHD simulation, we obtain values of the gas velocities, densities and turbulent stresses close to the gap edge, in one of the two gas streams that accrete onto the planet, and inside the low-density gap. The MHD values are then supplied to a Monte Carlo dust coagulation algorithm, which models grain sticking, compaction and bouncing. We consider two dust populations for each region: one whose initial size distribution is monodisperse, with monomer radius equal to 1 micron, and another one whose initial size distribution follows the Mathis-Rumpl-Nordsieck distribution for interstellar dust grains, with an initial range of monomer radii between 0.5 and 10 microns. Without bouncing, our Monte Carlo calculations show steady growth of dust aggregates in all regions, and the mass-weighted (MW) average porosity of the initially mono disperse population reaches extremely high final values of 98%. The final MW porosities in all other cases without bouncing range from 30% to 82%. The efficiency of compaction is due to high turbulent relative speeds between dust particles. When bouncing is introduced, growth is slowed down in the planetary wake and inside the gap.We also analyze the strength of the magnetic field threading the gaps opened by planets of different sub-Jovian masses. Preliminary results show that, in a gap opened by a large-mass planet (~ 1 MJ), the time-averaged radial profile of the vertical component of the field (Bz) increases sharply inside the gap, and less sharply in the case of less massive planets. In gaps opened by intermediate-mass planets (~ 0.5 — 0.75 MJ), the radial profile of Bz exhibits local maxima in the vicinity of the planet, but not at the gap center.

40 CFR Appendix B to Subpart E of... - Tables

Code of Federal Regulations, 2010 CFR

2010-07-01

... Variable-Speed Engines Test segment Mode number Engine speed 1 Observed torque 2 (percent of max. observed...'s specifications. Idle speed is specified by the manufacturer. 2 Torque (non-idle): Throttle fully open for 100 percent points. Other non-idle points: ± 2 percent of engine maximum value. Torque (idle...

Validation of Computer Aided Operations Research Facility (CAORF).

DTIC Science & Technology

1979-01-01

favorable comparison is that of the slow- down effect in performing a turn. From Figure 2.4 it is estimated that ship’s speed was reduced from an...initial speed of 17 knots to 6.6 knots. The data shown in Figure 2.3 for the CAORF ship indicate a reduction from an initial speed of 15 knots to 5.1 knots...follows: The ship is on a steady course at full sea speed . (Exact sea speed is optional.) At time zero, the rudder is put over 20 0 right. This is

Open tube guideway for high speed air cushioned vehicles

NASA Technical Reports Server (NTRS)

Goering, R. S. (Inventor)

1974-01-01

This invention is a tubular shaped guideway for high-speed air-cushioned supported vehicles. The tubular guideway is split and separated such that the sides of the guideway are open. The upper portion of the tubular guideway is supported above the lower portion by truss-like structural members. The lower portion of the tubular guideway may be supported by the terrain over which the vehicle travels, on pedestals or some similar structure.

Criterion validity and accuracy of global positioning satellite and data logging devices for wheelchair tennis court movement

PubMed Central

Sindall, Paul; Lenton, John P.; Whytock, Katie; Tolfrey, Keith; Oyster, Michelle L.; Cooper, Rory A.; Goosey-Tolfrey, Victoria L.

2013-01-01

Purpose To compare the criterion validity and accuracy of a 1 Hz non-differential global positioning system (GPS) and data logger device (DL) for the measurement of wheelchair tennis court movement variables. Methods Initial validation of the DL device was performed. GPS and DL were fitted to the wheelchair and used to record distance (m) and speed (m/second) during (a) tennis field (b) linear track, and (c) match-play test scenarios. Fifteen participants were monitored at the Wheelchair British Tennis Open. Results Data logging validation showed underestimations for distance in right (DLR) and left (DLL) logging devices at speeds >2.5 m/second. In tennis-field tests, GPS underestimated distance in five drills. DLL was lower than both (a) criterion and (b) DLR in drills moving forward. Reversing drill direction showed that DLR was lower than (a) criterion and (b) DLL. GPS values for distance and average speed for match play were significantly lower than equivalent values obtained by DL (distance: 2816 (844) vs. 3952 (1109) m, P = 0.0001; average speed: 0.7 (0.2) vs. 1.0 (0.2) m/second, P = 0.0001). Higher peak speeds were observed in DL (3.4 (0.4) vs. 3.1 (0.5) m/second, P = 0.004) during tennis match play. Conclusions Sampling frequencies of 1 Hz are too low to accurately measure distance and speed during wheelchair tennis. GPS units with a higher sampling rate should be advocated in further studies. Modifications to existing DL devices may be required to increase measurement precision. Further research into the validity of movement devices during match play will further inform the demands and movement patterns associated with wheelchair tennis. PMID:23820154

Determining the frequency of open windows in motor vehicles: a pilot study using a video camera in Houston, Texas during high temperature conditions.

PubMed

Long, Tom; Johnson, Ted; Ollison, Will

2002-05-01

Researchers have developed a variety of computer-based models to estimate population exposure to air pollution. These models typically estimate exposures by simulating the movement of specific population groups through defined microenvironments. Exposures in the motor vehicle microenvironment are significantly affected by air exchange rate, which in turn is affected by vehicle speed, window position, vent status, and air conditioning use. A pilot study was conducted in Houston, Texas, during September 2000 for a specific set of weather, vehicle speed, and road type conditions to determine whether useful information on the position of windows, sunroofs, and convertible tops could be obtained through the use of video cameras. Monitoring was conducted at three sites (two arterial roads and one interstate highway) on the perimeter of Harris County located in or near areas not subject to mandated Inspection and Maintenance programs. Each site permitted an elevated view of vehicles as they proceeded through a turn, thereby exposing all windows to the stationary video camera. Five videotaping sessions were conducted over a two-day period in which the Heat Index (HI)-a function of temperature and humidity-varied from 80 to 101 degrees F and vehicle speed varied from 30 to 74 mph. The resulting videotapes were processed to create a master database listing vehicle-specific data for site location, date, time, vehicle type (e.g., minivan), color, window configuration (e.g., four windows and sunroof), number of windows in each of three position categories (fully open, partially open, and closed), HI, and speed. Of the 758 vehicles included in the database, 140 (18.5 percent) were labeled as "open," indicating a window, sunroof, or convertible top was fully or partially open. The results of a series of stepwise linear regression analyses indicated that the probability of a vehicle in the master database being "open" was weakly affected by time of day, vehicle type, vehicle color, vehicle speed, and HI. In particular, open windows occurred more frequently when vehicle speed was less than 50 mph during periods when HI exceeded 99.9 degrees F and the vehicle was a minivan or passenger van. Overall, the pilot study demonstrated that data on factors affecting vehicle window position could be acquired through a relatively simple experimental protocol using a single video camera. Limitations of the study requiring further research include the inability to determine the status of the vehicle air conditioning system; lack of a wide range of weather, vehicle speed, and road type conditions; and the need to exclude some vehicles from statistical analyses due to ambiguous window positions.

Evaluating the performance of Sentinel-3 SRAL SAR Altimetry in the Coastal and Open Ocean, and developing improved retrieval methods - The ESA SCOOP Project.

NASA Astrophysics Data System (ADS)

Benveniste, J.; Cotton, D.; Moreau, T.; Varona, E.; Roca, M.; Cipollini, P.; Cancet, M.; Martin, F.; Fenoglio-Marc, L.; Naeije, M.; Fernandes, J.; Restano, M.; Ambrozio, A.

2016-12-01

The ESA Sentinel-3 satellite, launched in February 2016 as a part of the Copernicus programme, is the second satellite to operate a SAR mode altimeter. The Sentinel 3 Synthetic Aperture Radar Altimeter (SRAL) is based on the heritage from Cryosat-2, but this time complemented by a Microwave Radiometer (MWR) to provide a wet troposphere correction, and operating at Ku and C-Bands to provide an accurate along-track ionospheric correction. Together this instrument package, including both GPS and DORIS instruments for accurate positioning, allows accurate measurements of sea surface height over the ocean, as well as measurements of significant wave height and surface wind speed. SCOOP (SAR Altimetry Coastal & Open Ocean Performance) is a project funded under the ESA SEOM (Scientific Exploitation of Operational Missions) Programme Element, started in September 2015, to characterise the expected performance of Sentinel-3 SRAL SAR mode altimeter products, in the coastal zone and open-ocean, and then to develop and evaluate enhancements to the baseline processing scheme in terms of improvements to ocean measurements. There is also a work package to develop and evaluate an improved Wet Troposphere correction for Sentinel-3, based on the measurements from the on-board MWR, further enhanced mostly in the coastal and polar regions using third party data, and provide recommendations for use. At the end of the project recommendations for further developments and implementations will be provided through a scientific roadmap. In this presentation we provide an overview of the SCOOP project, highlighting the key deliverables and discussing the potential impact of the results in terms of the application of delay-Doppler (SAR) altimeter measurements over the open-ocean and coastal zone. We also present the initial results from the project, including: Key findings from a review of the current "state-of-the-art" for SAR altimetry, Specification of the initial "reference" delay-Doppler and echo modelling /retracking processing schemes, Evaluation of the initial Test Data Set in the Open Ocean and Coastal Zone Overview of modifications planned to the reference delay-Doppler and echo modelling/ re-tracking processing schemes.

Effect of Speed (Centrifugal Load) on Gear Crack Propagation Direction

NASA Technical Reports Server (NTRS)

Lewicki, David G.

2001-01-01

The effect of rotational speed (centrifugal force) on gear crack propagation direction was explored. Gears were analyzed using finite element analysis and linear elastic fracture mechanics. The analysis was validated with crack propagation experiments performed in a spur gear fatigue rig. The effects of speed, rim thickness, and initial crack location on gear crack propagation direction were investigated. Crack paths from the finite element method correlated well with those deduced from gear experiments. For the test gear with a backup ratio (rim thickness divided by tooth height) of nib = 0.5, cracks initiating in the tooth fillet propagated to rim fractures when run at a speed of 10,000 rpm and became tooth fractures for speeds slower than 10,000 rpm for both the experiments and anal sis. From additional analysis, speed had little effect on crack propagation direction except when initial crack locations were near the tooth/rim fracture transition point for a given backup ratio. When at that point, higher speeds tended to promote rim fracture while lower speeds (or neglecting centrifugal force) produced tooth fractures.

Method and apparatus for rapid thrust increases in a turbofan engine

NASA Technical Reports Server (NTRS)

Cornett, J. E.; Corley, R. C.; Fraley, T. O.; Saunders, A. A., Jr. (Inventor)

1980-01-01

Upon a landing approach, the normal compressor stator schedule of a fan speed controlled turbofan engine is temporarily varied to substantially close the stators to thereby increase the fuel flow and compressor speed in order to maintain fan speed and thrust. This running of the compressor at an off-design speed substantially reduces the time required to subsequently advance the engine speed to the takeoff thrust level by advancing the throttle and opening the compressor stators.

An open trial assessment of "The Number Race", an adaptive computer game for remediation of dyscalculia

PubMed Central

Wilson, Anna J; Revkin, Susannah K; Cohen, David; Cohen, Laurent; Dehaene, Stanislas

2006-01-01

Background In a companion article [1], we described the development and evaluation of software designed to remediate dyscalculia. This software is based on the hypothesis that dyscalculia is due to a "core deficit" in number sense or in its access via symbolic information. Here we review the evidence for this hypothesis, and present results from an initial open-trial test of the software in a sample of nine 7–9 year old children with mathematical difficulties. Methods Children completed adaptive training on numerical comparison for half an hour a day, four days a week over a period of five-weeks. They were tested before and after intervention on their performance in core numerical tasks: counting, transcoding, base-10 comprehension, enumeration, addition, subtraction, and symbolic and non-symbolic numerical comparison. Results Children showed specific increases in performance on core number sense tasks. Speed of subitizing and numerical comparison increased by several hundred msec. Subtraction accuracy increased by an average of 23%. Performance on addition and base-10 comprehension tasks did not improve over the period of the study. Conclusion Initial open-trial testing showed promising results, and suggested that the software was successful in increasing number sense over the short period of the study. However these results need to be followed up with larger, controlled studies. The issues of transfer to higher-level tasks, and of the best developmental time window for intervention also need to be addressed. PMID:16734906

Retrofit device and method to improve humidity control of vapor compression cooling systems

DOEpatents

Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

2016-08-16

A method and device for improving moisture removal capacity of a vapor compression system is disclosed. The vapor compression system is started up with the evaporator blower initially set to a high speed. A relative humidity in a return air stream is measured with the evaporator blower operating at the high speed. If the measured humidity is above the predetermined high relative humidity value, the evaporator blower speed is reduced from the initially set high speed to the lowest possible speed. The device is a control board connected with the blower and uses a predetermined change in measured relative humidity to control the blower motor speed.

Repeatable, accurate, and high speed multi-level programming of memristor 1T1R arrays for power efficient analog computing applications.

PubMed

Merced-Grafals, Emmanuelle J; Dávila, Noraica; Ge, Ning; Williams, R Stanley; Strachan, John Paul

2016-09-09

Beyond use as high density non-volatile memories, memristors have potential as synaptic components of neuromorphic systems. We investigated the suitability of tantalum oxide (TaOx) transistor-memristor (1T1R) arrays for such applications, particularly the ability to accurately, repeatedly, and rapidly reach arbitrary conductance states. Programming is performed by applying an adaptive pulsed algorithm that utilizes the transistor gate voltage to control the SET switching operation and increase programming speed of the 1T1R cells. We show the capability of programming 64 conductance levels with <0.5% average accuracy using 100 ns pulses and studied the trade-offs between programming speed and programming error. The algorithm is also utilized to program 16 conductance levels on a population of cells in the 1T1R array showing robustness to cell-to-cell variability. In general, the proposed algorithm results in approximately 10× improvement in programming speed over standard algorithms that do not use the transistor gate to control memristor switching. In addition, after only two programming pulses (an initialization pulse followed by a programming pulse), the resulting conductance values are within 12% of the target values in all cases. Finally, endurance of more than 10(6) cycles is shown through open-loop (single pulses) programming across multiple conductance levels using the optimized gate voltage of the transistor. These results are relevant for applications that require high speed, accurate, and repeatable programming of the cells such as in neural networks and analog data processing.

Comparison of Drop and Wind-Tunnel Experiments on Bomb Drag at High Subsonic Speeds

NASA Technical Reports Server (NTRS)

Gothert, B.

1948-01-01

The drag coefficients of bombs at high velocities velocity of fall was 97 percent of the speed of sound) (the highest are determined by drop tests and compared with measurements taken in the DVL high-speed closed wind tunnel and the open jet at AVA - Gottingen.

Comment on "Modified quantum-speed-limit bounds for open quantum dynamics in quantum channels"

NASA Astrophysics Data System (ADS)

Mirkin, Nicolás; Toscano, Fabricio; Wisniacki, Diego A.

2018-04-01

In a recent paper [Phys. Rev. A 95, 052118 (2017), 10.1103/PhysRevA.95.052118], the authors claim that our criticism, in Phys. Rev. A 94, 052125 (2016), 10.1103/PhysRevA.94.052125, to some quantum speed limit bounds for open quantum dynamics that appeared recently in literature are invalid. According to the authors, the problem with our analysis would be generated by an artifact of the finite-precision numerical calculations. We analytically show here that it is not possible to have any inconsistency associated with the numerical precision of calculations. Therefore, our criticism of the quantum speed limit bounds continues to be valid.

Torque coordinating robust control of shifting process for dry dual clutch transmission equipped in a hybrid car

NASA Astrophysics Data System (ADS)

Zhao, Z.-G.; Chen, H.-J.; Yang, Y.-Y.; He, L.

2015-09-01

For a hybrid car equipped with dual clutch transmission (DCT), the coordination control problems of clutches and power sources are investigated while taking full advantage of the integrated starter generator motor's fast response speed and high accuracy (speed and torque). First, a dynamic model of the shifting process is established, the vehicle acceleration is quantified according to the intentions of the driver, and the torque transmitted by clutches is calculated based on the designed disengaging principle during the torque phase. Next, a robust H∞ controller is designed to ensure speed synchronisation despite the existence of model uncertainties, measurement noise, and engine torque lag. The engine torque lag and measurement noise are used as external disturbances to initially modify the output torque of the power source. Additionally, during the torque switch phase, the torque of the power sources is smoothly transitioned to the driver's demanded torque. Finally, the torque of the power sources is further distributed based on the optimisation of system efficiency, and the throttle opening of the engine is constrained to avoid sharp torque variations. The simulation results verify that the proposed control strategies effectively address the problem of coordinating control of clutches and power sources, establishing a foundation for the application of DCT in hybrid cars.

Open science initiatives: challenges for public health promotion.

PubMed

Holzmeyer, Cheryl

2018-03-07

While academic open access, open data and open science initiatives have proliferated in recent years, facilitating new research resources for health promotion, open initiatives are not one-size-fits-all. Health research particularly illustrates how open initiatives may serve various interests and ends. Open initiatives not only foster new pathways of research access; they also discipline research in new ways, especially when associated with new regimes of research use and peer review, while participating in innovation ecosystems that often perpetuate existing systemic biases toward commercial biomedicine. Currently, many open initiatives are more oriented toward biomedical research paradigms than paradigms associated with public health promotion, such as social determinants of health research. Moreover, open initiatives too often dovetail with, rather than challenge, neoliberal policy paradigms. Such initiatives are unlikely to transform existing health research landscapes and redress health inequities. In this context, attunement to social determinants of health research and community-based local knowledge is vital to orient open initiatives toward public health promotion and health equity. Such an approach calls for discourses, norms and innovation ecosystems that contest neoliberal policy frameworks and foster upstream interventions to promote health, beyond biomedical paradigms. This analysis highlights challenges and possibilities for leveraging open initiatives on behalf of a wider range of health research stakeholders, while emphasizing public health promotion, health equity and social justice as benchmarks of transformation.

Reaction time and anticipatory skill of athletes in open and closed skill-dominated sport.

PubMed

Nuri, Leila; Shadmehr, Azadeh; Ghotbi, Nastaran; Attarbashi Moghadam, Behrouz

2013-01-01

In sports, reaction time and anticipatory skill are critical aspects of perceptual abilities. To date, no study has compared reaction time and anticipatory skill of athletes from open and closed skill-dominated sport. Accordingly, the present study investigated whether a difference exists in sensory-cognitive skills between these two different sport domains. Eleven volleyball players and 11 sprinters participated in this experiment. Reaction time and anticipatory skill of both groups were recorded by a custom-made software called SART (speed anticipation and reaction time test). This software consists of six sensory-cognitive tests that evaluate visual choice reaction time, visual complex choice reaction time, auditory choice reaction time, auditory complex choice reaction time, and anticipatory skill of the high speed and low speed of the ball. For each variable, an independent t-test was performed. Results suggested that sprinters were better in both auditory reaction times (P<0.001 for both tests) and volleyball players were better in both anticipatory skill tests (P = 0.007 and P = 0.04 for anticipatory skill of the high speed and low speed of the ball, respectively). However, no significant differences were found in both visual choice reaction time tests (P > 0.05 for both visual reaction time tests). It is concluded that athletes have greater sensory-cognitive skills related to their specific sport domain either open or closed.

Comparison of Taxi Time Prediction Performance Using Different Taxi Speed Decision Trees

NASA Technical Reports Server (NTRS)

Lee, Hanbong

2017-01-01

In the STBO modeler and tactical surface scheduler for ATD-2 project, taxi speed decision trees are used to calculate the unimpeded taxi times of flights taxiing on the airport surface. The initial taxi speed values in these decision trees did not show good prediction accuracy of taxi times. Using the more recent, reliable surveillance data, new taxi speed values in ramp area and movement area were computed. Before integrating these values into the STBO system, we performed test runs using live data from Charlotte airport, with different taxi speed settings: 1) initial taxi speed values and 2) new ones. Taxi time prediction performance was evaluated by comparing various metrics. The results show that the new taxi speed decision trees can calculate the unimpeded taxi-out times more accurately.

Three-dimensional numerical simulation of gradual opening in a wave rotor passage

NASA Technical Reports Server (NTRS)

Larosiliere, Louis M.

1993-01-01

The evolution of the contact interface and the propagation of compression waves inside a single wave rotor passage gradually opening to and traversing an inlet port is studied numerically using an inviscid formulation of the governing equations. Insights into the response of the interface and kinematics of the flow field to various opening times are given. Since the opening time is inversely proportional to the rotational speed of the rotor, the effects of passage rotation such as centripetal and Coriolis accelerations are intrinsically coupled to the gradual opening process. Certain three-dimensional features associated with the gradual opening process as a result of centripetal and Coriolis accelerations are illustrated. For the range of opening times or rotational speeds considered, a portion of the interface behaves like a vortex sheet that can degenerate into a complex interfacial structure. The vortices produced along the interface can serve as a stirring mechanism to promote local mixing. Coriolis and centripetal accelerations can introduce three dimensional effects such as interfacial distortions in meridional planes and spanwise migration of fluid elements.

Dissipation and Residues of Pyrethrins in Leaf Lettuce under Greenhouse and Open Field Conditions.

PubMed

Pan, Lixiang; Feng, Xiaoxiao; Zhang, Hongyan

2017-07-21

Pyrethrins are nowadays widely used for prevention and control of insects in leaf lettuce. However, there is a concern about the pesticide residue in leaf lettuce. A reliable analytical method for determination of pyrethrins (pyrethrin-and П, cinerin І and П, and jasmolin І and П) in leaf lettuce was developed by using gas chromatography-mass spectrometry (GC-MS). Recoveries of pyrethrins in leaf lettuce at three spiking levels were 99.4-104.0% with relative standard deviations of 0.9-3.1% ( n = 5). Evaluation of dissipation and final residues of pyrethrins in leaf lettuce were determined at six different locations, including the open field, as well as under greenhouse conditions. The initial concentration of pyrethrins in greenhouse (0.57 mg/kg) was higher than in open field (0.25 mg/kg) and the half-life for pyrethrins disappearance in field lettuce (0.7 days) was less than that greenhouse lettuce (1.1 days). Factors such as rainfall, solar radiation, wind speed, and crop growth rate are likely to have caused these results. The final residue in leaf lettuce was far below the maximum residue limits (MRLs) (1 mg/kg established by the European Union (EU), Australia, Korea, Japan).

A Kind of Optimization Method of Loading Documents in OpenOffice.org

NASA Astrophysics Data System (ADS)

Lan, Yuqing; Li, Li; Zhou, Wenbin

As a giant in open source community, OpenOffice.org has become the most popular office suite within Linux community. But OpenOffice.org is relatively slow while loading documents. Research shows that the most time consuming part is importing one page of whole document. If there are many pages in a document, the accumulation of time consumed can be astonishing. Therefore, this paper proposes a solution, which has improved the speed of loading documents through asynchronous importing mechanism: a document is not imported as a whole, but only part of the document is imported at first for display, then mechanism in the background is started to asynchronously import the remaining parts, and insert it into the drawing queue of OpenOffice.org for display. In this way, the problem can be solved and users don't have to wait for a long time. Application start-up time testing tool has been used to test the time consumed in loading different pages of documents before and after optimization of OpenOffice.org, then, we adopt the regression theory to analyse the correlation between the page number of documents and the loading time. In addition, visual modeling of the experimental data are acquired with the aid of matlab. An obvious increase in loading speed can be seen after a comparison of the time consumed to load a document before and after the solution is adopted. And then, using Microsoft Office compared with the optimized OpenOffice.org, their loading speeds are almost same. The results of the experiments show the effectiveness of this solution.

High performance systems

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

Vigil, M.B.

1995-03-01

This document provides a written compilation of the presentations and viewgraphs from the 1994 Conference on High Speed Computing given at the High Speed Computing Conference, {open_quotes}High Performance Systems,{close_quotes} held at Gleneden Beach, Oregon, on April 18 through 21, 1994.

Quantum speed limits in open system dynamics.

PubMed

del Campo, A; Egusquiza, I L; Plenio, M B; Huelga, S F

2013-02-01

Bounds to the speed of evolution of a quantum system are of fundamental interest in quantum metrology, quantum chemical dynamics, and quantum computation. We derive a time-energy uncertainty relation for open quantum systems undergoing a general, completely positive, and trace preserving evolution which provides a bound to the quantum speed limit. When the evolution is of the Lindblad form, the bound is analogous to the Mandelstam-Tamm relation which applies in the unitary case, with the role of the Hamiltonian being played by the adjoint of the generator of the dynamical semigroup. The utility of the new bound is exemplified in different scenarios, ranging from the estimation of the passage time to the determination of precision limits for quantum metrology in the presence of dephasing noise.

[Construction of DICOM-WWW gateway by open source, and application to PDAs using the high-speed mobile communications network].

PubMed

Yokohama, Noriya

2003-09-01

The author constructed a medical image network system using open source software that took security into consideration. This system was enabled for search and browse with a WWW browser, and images were stored in a DICOM server. In order to realize this function, software was developed to fill in the gap between the DICOM protocol and HTTP using PHP language. The transmission speed was evaluated by the difference in protocols between DICOM and HTTP. Furthermore, an attempt was made to evaluate the convenience of medical image access with a personal information terminal via the Internet through the high-speed mobile communication terminal. Results suggested the feasibility of remote diagnosis and application to emergency care.

Plastification of polymers in twin-screw-extruders: New visualization technic using high-speed imaging

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

Knieper, A., E-mail: Alexander.Knieper@lbf.fraunhofer.de, E-mail: Christian.Beinert@lbf.fraunhofer.de; Beinert, C., E-mail: Alexander.Knieper@lbf.fraunhofer.de, E-mail: Christian.Beinert@lbf.fraunhofer.de

The initial melting of the first granules through plastic energy dissipation (PED) at the beginning of the melting zone, in the co-rotating twin-screw extruder is visualized in this work. The visualization was created through the use of a high speed camera in the cross section of the melting zone. The parameters screw speed, granule-temperature, temperature-profile, type of polymer and back pressure were examined. It was shown that the screw speed and the temperature-profile have significant influence on the rate of initial melting.

Direct Measurement of the Speed of Sound Using a Microphone and a Speaker

ERIC Educational Resources Information Center

Gómez-Tejedor, José A.; Castro-Palacio, Juan C.; Monsoriu, Juan A.

2014-01-01

We present a simple and accurate experiment to obtain the speed of sound in air using a conventional speaker and a microphone connected to a computer. A free open source digital audio editor and recording computer software application allows determination of the time-of-flight of the wave for different distances, from which the speed of sound is…

Reconstruction of geomagnetic activity and near-Earth interplanetary conditions over the past 167 yr - Part 4: Near-Earth solar wind speed, IMF, and open solar flux

NASA Astrophysics Data System (ADS)

Lockwood, M.; Nevanlinna, H.; Barnard, L.; Owens, M. J.; Harrison, R. G.; Rouillard, A. P.; Scott, C. J.

2014-04-01

In the concluding paper of this tetralogy, we here use the different geomagnetic activity indices to reconstruct the near-Earth interplanetary magnetic field (IMF) and solar wind flow speed, as well as the open solar flux (OSF) from 1845 to the present day. The differences in how the various indices vary with near-Earth interplanetary parameters, which are here exploited to separate the effects of the IMF and solar wind speed, are shown to be statistically significant at the 93% level or above. Reconstructions are made using four combinations of different indices, compiled using different data and different algorithms, and the results are almost identical for all parameters. The correction to the aa index required is discussed by comparison with the Ap index from a more extensive network of mid-latitude stations. Data from the Helsinki magnetometer station is used to extend the aa index back to 1845 and the results confirmed by comparison with the nearby St Petersburg observatory. The optimum variations, using all available long-term geomagnetic indices, of the near-Earth IMF and solar wind speed, and of the open solar flux, are presented; all with ±2σ uncertainties computed using the Monte Carlo technique outlined in the earlier papers. The open solar flux variation derived is shown to be very similar indeed to that obtained using the method of Lockwood et al. (1999).

Driving behaviour responses to a moose encounter, automatic speed camera, wildlife warning sign and radio message determined in a factorial simulator study.

PubMed

Jägerbrand, Annika K; Antonson, Hans

2016-01-01

In a driving simulator study, driving behaviour responses (speed and deceleration) to encountering a moose, automatic speed camera, wildlife warning sign and radio message, with or without a wildlife fence and in dense forest or open landscape, were analysed. The study consisted of a factorial experiment that examined responses to factors singly and in combination over 9-km road stretches driven eight times by 25 participants (10 men, 15 women). The aims were to: determine the most effective animal-vehicle collision (AVC) countermeasures in reducing vehicle speed and test whether these are more effective in combination for reducing vehicle speed; identify the most effective countermeasures on encountering moose; and determine whether the driving responses to AVC countermeasures are affected by the presence of wildlife fences and landscape characteristics. The AVC countermeasures that proved most effective in reducing vehicle speed were a wildlife warning sign and radio message, while automatic speed cameras had a speed-increasing effect. There were no statistically significant interactions between different countermeasures and moose encounters. However, there was a tendency for a stronger speed-reducing effect from the radio message warning and from a combination of a radio message and wildlife warning sign in velocity profiles covering longer driving distances than the statistical tests. Encountering a moose during the drive had the overall strongest speed-reducing effect and gave the strongest deceleration, indicating that moose decoys or moose artwork might be useful as speed-reducing countermeasures. Furthermore, drivers reduced speed earlier on encountering a moose in open landscape and had lower velocity when driving past it. The presence of a wildlife fence on encountering the moose resulted in smaller deceleration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extending the process limits of laser polymer welding with high-brilliance beam sources (recent status and prospects of POLYBRIGHT)

NASA Astrophysics Data System (ADS)

Olowinsky, A.; Boglea, A.

2011-03-01

Plastics play an important role in almost every facet of our lives and constitute a wide variety of products, from everyday products such as food and beverage packaging, over furniture and building materials to high tech products in the automotive, electronics, aerospace, white goods, medical and other sectors [1]. The objective of PolyBright, the European Research project on laser polymer welding, is to provide high speed and flexible laser manufacturing technology and expand the limits of current plastic part assembly. New laser polymer joining processes for optimized thermal management in combination with adapted wavelengths will provide higher quality, high processing speed up to 1 m/s and robust manufacturing processes at lower costs. Key innovations of the PolyBright project are fibre lasers with high powers up to 500 W, high speed scanning and flexible beam manipulation systems for simultaneous welding and high-resolution welding, such as dynamic masks and multi kHz scanning heads. With this initial step, PolyBright will break new paths in processing of advanced plastic products overcoming the quality and speed limitations of conventional plastic part assembly. Completely new concepts for high speed processing, flexibility and quality need to be established in combination with high brilliance lasers and related equipment. PolyBright will thus open new markets for laser systems with a short term potential of over several 100 laser installations per year and a future much larger market share in the still growing plastic market. PolyBright will hence establish a comprehensive and sustainable development activity on new high brilliance lasers that will strengthen the laser system industry.

DUST COAGULATION IN THE VICINITY OF A GAP-OPENING JUPITER-MASS PLANET

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

Carballido, Augusto; Matthews, Lorin S.; Hyde, Truell W., E-mail: Augusto_Carballido@baylor.edu

We analyze the coagulation of dust in and around a gap opened by a Jupiter-mass planet. To this end, we carry out a high-resolution magnetohydrodynamic (MHD) simulation of the gap environment, which is turbulent due to the magnetorotational instability. From the MHD simulation, we obtain values of the gas velocities, densities, and turbulent stresses (a) close to the gap edge, (b) in one of the two gas streams that accrete onto the planet, (c) inside the low-density gap, and (d) outside the gap. The MHD values are then input into a Monte Carlo dust-coagulation algorithm which models grain sticking andmore » compaction. We also introduce a simple implementation for bouncing, for comparison purposes. We consider two dust populations for each region: one whose initial size distribution is monodisperse, with monomer radius equal to 1 μ m, and another one whose initial size distribution follows the Mathis–Rumpl–Nordsieck distribution for interstellar dust grains, with an initial range of monomer radii between 0.5 and 10 μ m. Without bouncing, our Monte Carlo calculations show steady growth of dust aggregates in all regions, and the mass-weighted (m-w) average porosity of the initially monodisperse population reaches extremely high final values of 98%. The final m-w porosities in all other cases without bouncing range between 30% and 82%. The efficiency of compaction is due to high turbulent relative speeds between dust particles. When bouncing is introduced, growth is slowed down in the planetary wake and inside the gap. Future studies will need to explore the effect of different planet masses and electric charge on grains.« less

Typhoon air-sea drag coefficient in coastal regions

NASA Astrophysics Data System (ADS)

Zhao, Zhong-Kuo; Liu, Chun-Xia; Li, Qi; Dai, Guang-Feng; Song, Qing-Tao; Lv, Wei-Hua

2015-02-01

The air-sea drag during typhoon landfalls is investigated for a 10 m wind speed as high as U10 ≈ 42 m s-1, based on multilevel wind measurements from a coastal tower located in the South China Sea. The drag coefficient (CD) plotted against the typhoon wind speed is similar to that of open ocean conditions; however, the CD curve shifts toward a regime of lower winds, and CD increases by a factor of approximately 0.5 relative to the open ocean. Our results indicate that the critical wind speed at which CD peaks is approximately 24 m s-1, which is 5-15 m s-1 lower than that from deep water. Shoaling effects are invoked to explain the findings. Based on our results, the proposed CD formulation, which depends on both water depth and wind speed, is applied to a typhoon forecast model. The forecasts of typhoon track and surface wind speed are improved. Therefore, a water-depth-dependence formulation of CD may be particularly pertinent for parameterizing air-sea momentum exchanges over shallow water.

Evaluation of solar Type II radio burst estimates of initial solar wind shock speed using a kinematic model of the solar wind on the April 2001 solar event swarm

NASA Astrophysics Data System (ADS)

Sun, W.; Dryer, M.; Fry, C. D.; Deehr, C. S.; Smith, Z.; Akasofu, S.-I.; Kartalev, M. D.; Grigorov, K. G.

2002-04-01

We compare simulation results of real time shock arrival time prediction with observations by the ACE satellite for a series of solar flares/coronal mass ejections which took place between 28 March and 18 April, 2001 on the basis of the Hakamada-Akasofu-Fry, version 2 (HAFv.2) model. It is found, via an ex post facto calculation, that the initial speed of shock waves as an input parameter of the modeling is crucial for the agreement between the observation and the simulation. The initial speed determined by metric Type II radio burst observations must be substantially reduced (30 percent in average) for most high-speed shock waves.

In Parkinson's disease STN stimulation enhances responsiveness of movement initiation speed to high reward value.

PubMed

Kojovic, Maja; Higgins, Andrea; Jahanshahi, Marjan

2016-08-01

The subthalamic nucleus (STN) is part of the motor, associative, and limbic cortico-striatal circuits through which it can influence a range of behaviours, with preclinical and clinical evidence suggesting that the STN is involved in motivational modulation of behaviour. In the present study, we investigated if in Parkinson's disease (PD) motivational modulation of movement speed is altered by deep brain stimulation (DBS) of the STN (STN-DBS). We studied the effect of monetary incentive on speed of movement initiation and execution in a computer-based simple reaction time task in 10 operated patients with Parkinson's disease using a STN DBS ON/OFF design and also in 11 healthy participants. Prospect of reward improved speed of movement initiation in PD patients both with STN-DBS ON and OFF. However, only with STN-DBS ON, the patients showed greater speeding of initiation time with higher reward magnitude, suggesting enhanced responsivity to higher reward value. Also, on the rewarded trials, PD patients ON stimulation made more anticipation errors than on unrewarded trials, reflecting a propensity to impulsive responses triggered by prospect of reward by subthalamic stimulation. The motivational modulation of movement speed was preserved and enhanced in PD with STN-DBS. Motivational modulation of movement speed in PD is maintained with STN-DBS, with STN stimulation having a further energizing effect on movement initiation in response to greater incentive value. Our results suggest that STN plays a role in integrating motivational influences into motor action, which may explain some previous reports of STN-DBS induced impulsivity with increased motivational salience of stimuli. Copyright © 2016. Published by Elsevier Ltd.

The influence of cutting speed and cutting initiation location in specimen preparation for the microtensile bond strength test.

PubMed

Abreu, Celina Wanderley; Santosb, Jarbas F; Passos, Sheila Pestana; Michida, Silvia Masae; Takahashi, Fernando Eidi; Bottino, Marco Antonio

2011-06-01

This study evaluated the effect of cutting initiation location and cutting speed on the bond strength between resin cement and feldspathic ceramic. Thirty-six blocks (6.4 x 6.4 x 4.8 mm) of ceramic (Vita VM7) were produced. The ceramic surfaces were etched with 10% hydrofluoric acid gel for 60 s and then silanized. Each ceramic block was placed in a silicon mold with the treated surface exposed. A resin cement (Variolink II) was injected into the mold over the treated surface and polymerized. The resin cement-ceramic blocks were divided into two groups according to experimental conditions: a) cutting initiation location - resin cement, ceramic and interface; and b) cutting speed - 10,000, 15,000, and 20,000 rpm. The specimens were sectioned to achieve non-trimmed bar specimens. The microtensile test was performed in a universal testing machine (1 mm/min). The failure modes were examined using an optical light microscope and SEM. Bond strength results were analyzed using one-way ANOVA and Tukey's test (α = 0.05). Significant influences of cutting speed and initiation location on bond strength (p < 0.05) were observed. The highest mean was achieved for specimens cut at 15,000 rpm at the interface (15.12 ± 5.36 MPa). The lowest means were obtained for specimens cut at the highest cutting speed in resin cement (8.50 ± 3.27 MPa), and cut at the lowest cutting speed in ceramic (8.60 ± 2.65 MPa). All groups showed mainly mixed failure (75% to 100%). The cutting speed and initiation location are important factors that should be considered during specimen preparation for microtensile bond strength testing, as both may influence the bond strength results.

Penetration and Duration of Fuel Sprays from a Pump Injection System

NASA Technical Reports Server (NTRS)

Rothrock, A M; Marsh, E T

1931-01-01

High-speed motion pictures were taken of individual fuel sprays from a pump injection system. The changes in the spray-tip penetration with changes in the pump speed, injection-valve opening and closing pressures, discharge-orifice area, injection-tube length and diameter, and pump throttle setting were measured. In addition, the effects of the variables on the time lag and duration of injection can be controlled by the dimensions of the injection tube, the area of the discharge orifice, and the injection-valve opening and closing pressures.

Penetration and Duration of Fuel Sprays from a Pump Injection System

NASA Technical Reports Server (NTRS)

Rothrock, A M; Marsh, E T

1934-01-01

High-speed motion pictures were taken of individual fuel sprays from a pump injection system. The changes in the spray-tip penetration with changes in the pump speed, injection-valve opening and closing pressures, discharge-orifice area, injection-tube length and diameter, and pump throttle setting were measured. The pump was used with and without a check valve. The results show that the penetration of the spray tip can be controlled by the dimensions of the injection tube, the area of the discharge orifice, and the injection-valve opening and closing pressures.

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

Gearhart, Jared Lee; Adair, Kristin Lynn; Durfee, Justin David.

When developing linear programming models, issues such as budget limitations, customer requirements, or licensing may preclude the use of commercial linear programming solvers. In such cases, one option is to use an open-source linear programming solver. A survey of linear programming tools was conducted to identify potential open-source solvers. From this survey, four open-source solvers were tested using a collection of linear programming test problems and the results were compared to IBM ILOG CPLEX Optimizer (CPLEX) [1], an industry standard. The solvers considered were: COIN-OR Linear Programming (CLP) [2], [3], GNU Linear Programming Kit (GLPK) [4], lp_solve [5] and Modularmore » In-core Nonlinear Optimization System (MINOS) [6]. As no open-source solver outperforms CPLEX, this study demonstrates the power of commercial linear programming software. CLP was found to be the top performing open-source solver considered in terms of capability and speed. GLPK also performed well but cannot match the speed of CLP or CPLEX. lp_solve and MINOS were considerably slower and encountered issues when solving several test problems.« less

The forming simulation of flexible glass with silt down draw method

NASA Astrophysics Data System (ADS)

Yansheng, Hou; Jinshu, Cheng; Junfeng, Kang; Jing, Cui

2018-03-01

The slit down draw method is the main manufacturing process of flexible glass. In this study, Flow3DTM software was used to simulate the process of drawing and thinning glass slits during the slit down draw process. The influence of glass viscosity, initial plate thickness and initial plate speed on the glass spreading process was studied. The maximum pull-down force that the root can bear is linearly proportional to the viscosity, the initial thickness of 1.3837 power and the initial plate speed, respectively. The best way to improve the tensile strength of flexible glass is to increase the viscosity. Flexible glass was more easily to obtain with low viscosity, low thickness and low drawing speed.

Research notes : high-speed rail survey results.

DOT National Transportation Integrated Search

2010-08-01

The survey was conducted from April 2010 to June 2010 using both a print and a web version with identical questions. The print version of the survey was distributed at open house meetings on high-speed rail held in Eugene, Junction City, Albany, Sale...

Cost-benefit evaluation of large truck-automobile speed limit differentials on rural interstate highways.

DOT National Transportation Integrated Search

2005-11-01

Speed differentials between large trucks and automobiles on rural interstate highways are due to : both state regulated speed limits and commercial trucking company policies that restrict maximum truck : speeds. The initial portion of this effort inv...

European birds adjust their flight initiation distance to road speed limits.

PubMed

Legagneux, Pierre; Ducatez, Simon

2013-10-23

Behavioural responses can help species persist in habitats modified by humans. Roads and traffic greatly affect animals' mortality not only through habitat structure modifications but also through direct mortality owing to collisions. Although species are known to differ in their sensitivity to the risk of collision, whether individuals can change their behaviour in response to this is still unknown. Here, we tested whether common European birds changed their flight initiation distances (FIDs) in response to vehicles according to road speed limit (a known factor affecting killing rates on roads) and vehicle speed. We found that FID increased with speed limit, although vehicle speed had no effect. This suggests that birds adjust their flight distance to speed limit, which may reduce collision risks and decrease mortality maximizing the time allocated to foraging behaviours. Mobility and territory size are likely to affect an individuals' ability to respond adaptively to local speed limits.

Citizen Science Initiatives: Engaging the Public and Demystifying Science

PubMed Central

Van Vliet, Kim; Moore, Claybourne

2016-01-01

The Internet and smart phone technologies have opened up new avenues for collaboration among scientists around the world. These technologies have also expanded citizen science opportunities and public participation in scientific research (PPSR). Here we discuss citizen science, what it is, who does it, and the variety of projects and methods used to increase scientific knowledge and scientific literacy. We describe a number of different types of citizen-science projects. These greatly increase the number of people involved, helping to speed the pace of data analysis and allowing science to advance more rapidly. As a result of the numerous advantages of citizen-science projects, these opportunities are likely to expand in the future and increase the rate of novel discoveries. PMID:27047582

Improved turbopump dynamics

NASA Technical Reports Server (NTRS)

Kiefling, L.

1985-01-01

A study was initiated to investigate the practicality of increasing rotor critical speeds by changes in manufacturing method. The technique would be to build a pump with an all laser welded shaft and case; such unit to be opened by laser cutting and rebuilt by rewelding the same surface. Use of a split casing, common in industry, would permit assembly of the rotor outside the case. A team was formed to perform the study; however, the work of the team was severely restricted by conflict with higher priority tasks. No manpower was available to evaluate alternate configurations. Thus, much of the synergetic effects of cohesive design modification was lost. Although very limited results were achieved, nothing was found to indicate that the method is not worth further investigation.

Progress in Unsteady Turbopump Flow Simulations Using Overset Grid Systems

NASA Technical Reports Server (NTRS)

Kiris, Cetin C.; Chan, William; Kwak, Dochan

2002-01-01

This viewgraph presentation provides information on unsteady flow simulations for the Second Generation RLV (Reusable Launch Vehicle) baseline turbopump. Three impeller rotations were simulated by using a 34.3 million grid points model. MPI/OpenMP hybrid parallelism and MLP shared memory parallelism has been implemented and benchmarked in INS3D, an incompressible Navier-Stokes solver. For RLV turbopump simulations a speed up of more than 30 times has been obtained. Moving boundary capability is obtained by using the DCF module. Scripting capability from CAD geometry to solution is developed. Unsteady flow simulations for advanced consortium impeller/diffuser by using a 39 million grid points model are currently underway. 1.2 impeller rotations are completed. The fluid/structure coupling is initiated.

Citizen Science Initiatives: Engaging the Public and Demystifying Science.

PubMed

Van Vliet, Kim; Moore, Claybourne

2016-03-01

The Internet and smart phone technologies have opened up new avenues for collaboration among scientists around the world. These technologies have also expanded citizen science opportunities and public participation in scientific research (PPSR). Here we discuss citizen science, what it is, who does it, and the variety of projects and methods used to increase scientific knowledge and scientific literacy. We describe a number of different types of citizen-science projects. These greatly increase the number of people involved, helping to speed the pace of data analysis and allowing science to advance more rapidly. As a result of the numerous advantages of citizen-science projects, these opportunities are likely to expand in the future and increase the rate of novel discoveries.

Performance comparison analysis library communication cluster system using merge sort

NASA Astrophysics Data System (ADS)

Wulandari, D. A. R.; Ramadhan, M. E.

2018-04-01

Begins by using a single processor, to increase the speed of computing time, the use of multi-processor was introduced. The second paradigm is known as parallel computing, example cluster. The cluster must have the communication potocol for processing, one of it is message passing Interface (MPI). MPI have many library, both of them OPENMPI and MPICH2. Performance of the cluster machine depend on suitable between performance characters of library communication and characters of the problem so this study aims to analyze the comparative performances libraries in handling parallel computing process. The case study in this research are MPICH2 and OpenMPI. This case research execute sorting’s problem to know the performance of cluster system. The sorting problem use mergesort method. The research method is by implementing OpenMPI and MPICH2 on a Linux-based cluster by using five computer virtual then analyze the performance of the system by different scenario tests and three parameters for to know the performance of MPICH2 and OpenMPI. These performances are execution time, speedup and efficiency. The results of this study showed that the addition of each data size makes OpenMPI and MPICH2 have an average speed-up and efficiency tend to increase but at a large data size decreases. increased data size doesn’t necessarily increased speed up and efficiency but only execution time example in 100000 data size. OpenMPI has a execution time greater than MPICH2 example in 1000 data size average execution time with MPICH2 is 0,009721 and OpenMPI is 0,003895 OpenMPI can customize communication needs.

A comparison of linear speed, closed-skill agility, and open-skill agility qualities between backcourt and frontcourt adult semiprofessional male basketball players.

PubMed

Scanlan, Aaron T; Tucker, Patrick S; Dalbo, Vincent J

2014-05-01

The measurement of fitness qualities relevant to playing position is necessary to inform basketball coaching and conditioning staff of role-related differences in playing groups. To date, sprinting and agility performance have not been compared between playing positions in adult male basketball players. Therefore, the purpose of this study was to describe and compare linear speed, closed-skill agility, and open-skill agility qualities between backcourt (point guard and shooting guard positions) and frontcourt (small forward, power forward, and center positions) semiprofessional basketball players. Six backcourt (mean ± SD: age, 24.3 ± 7.9 years; stature, 183.4 ± 4.0 cm; body mass, 85.5 ± 12.3 kg; VO2max, 51.9 ± 4.8 ml·kg(-1)·min(-1)) and 6 frontcourt (mean ± SD: age, 27.5 ± 5.5 years; stature, 194.4 ± 7.1 cm; body mass, 109.4 ± 8.8 kg; VO2max, 47.1 ± 5.0 ml·kg(-1)·min(-1)) adult male basketball players completed 20-m sprint, closed-skill agility, and open-skill agility performance tests. Magnitude-based inferences revealed that backcourt players (5 m, 1.048 ± 0.027 seconds; 10 m, 1.778 ± 0.048 seconds; 20 m, 3.075 ± 0.121 seconds) possessed likely quicker linear sprint times than frontcourt players (5 m, 1.095 ± 0.085 seconds; 10 m, 1.872 ± 0.127 seconds; 20 m, 3.242 ± 0.221 seconds). Conversely, frontcourt players (1.665 ± 0.096 seconds) held possible superior closed-skill agility performance than backcourt players (1.613 ± 0.111 seconds). In addition, unclear positional differences were apparent for open-skill agility qualities. These findings indicate that linear speed and change of direction speed might be differently developed across playing positions. Furthermore, position-related functions might similarly depend on the aspects of open-skill agility performance across backcourt and frontcourt players. Basketball coaching and conditioning staff should consider the development of position-targeted training drills to improve speed, agility, and cognitive qualities in players.

Resonance tube phonation in water: High-speed imaging, electroglottographic and oral pressure observations of vocal fold vibrations--a pilot study.

PubMed

Granqvist, Svante; Simberg, Susanna; Hertegård, Stellan; Holmqvist, Sofia; Larsson, Hans; Lindestad, Per-Åke; Södersten, Maria; Hammarberg, Britta

2015-10-01

Phonation into glass tubes ('resonance tubes'), keeping the free end of the tube in water, has been a frequently used voice therapy method in Finland and more recently also in other countries. The purpose of this exploratory study was to investigate what effects tube phonation with and without water has on the larynx. Two participants were included in the study. The methods used were high-speed imaging, electroglottographic observations of vocal fold vibrations, and measurements of oral pressure during tube phonation. Results showed that the fluctuation in the back pressure during tube phonation in water altered the vocal fold vibrations. In the high-speed imaging, effects were found in the open quotient and amplitude variation of the glottal opening. The open quotient increased with increasing water depth (from 2 cm to 6 cm). A modulation effect by the water bubbles on the vocal fold vibrations was seen both in the high-speed glottal area tracings and in the electroglottography signal. A second experiment revealed that the increased average oral pressure was largely determined by the water depth. The increased open quotient can possibly be explained by an increased abduction of the vocal folds and/or a reduced transglottal pressure. The back pressure of the bubbles also modulates glottal vibrations with a possible 'massage' effect on the vocal folds. This effect and the well-defined average pressure increase due to the known water depth are different from those of other methods using a semi-occluded vocal tract.

Joint High Speed Vessel (JHSV) Follow on Operational Test and Evaluation (FOT and E) Report

DTIC Science & Technology

2015-09-21

Speed Vessel (JHSV) ship class. The events covered in this testing were not performed during the Initial Operational Test and Evaluation ( IOT &E...support boats since launch of these type boats was completed in IOT &E. 1 “Initial Operational Test...and Evaluation ( IOT &E) with Live Fire Test and Evaluation (LFT&E) on Joint High Speed Vessel (JHSV),” DOT&E, July 17, 2014. 2 MLP (CCS) is a heavy

Active control system for high speed windmills

DOEpatents

Avery, D.E.

1988-01-12

A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed. 4 figs.

Active control system for high speed windmills

DOEpatents

Avery, Don E.

1988-01-01

A pump stroke is matched to the operating speed of a high speed windmill. The windmill drives a hydraulic pump for a control. Changes in speed of a wind driven shaft open supply and exhaust valves to opposite ends of a hydraulic actuator to lengthen and shorten an oscillating arm thereby lengthening and shortening the stroke of an output pump. Diminishing wind to a stall speed causes the valves to operate the hydraulic cylinder to shorten the oscillating arm to zero. A pressure accumulator in the hydraulic system provides the force necessary to supply the hydraulic fluid under pressure to drive the actuator into and out of the zero position in response to the windmill shaft speed approaching and exceeding windmill stall speed.

Turbulent Heating and Wave Pressure in Solar Wind Acceleration Modeling: New Insights to Empirical Forecasting of the Solar Wind

NASA Astrophysics Data System (ADS)

Woolsey, L. N.; Cranmer, S. R.

2013-12-01

The study of solar wind acceleration has made several important advances recently due to improvements in modeling techniques. Existing code and simulations test the competing theories for coronal heating, which include reconnection/loop-opening (RLO) models and wave/turbulence-driven (WTD) models. In order to compare and contrast the validity of these theories, we need flexible tools that predict the emergent solar wind properties from a wide range of coronal magnetic field structures such as coronal holes, pseudostreamers, and helmet streamers. ZEPHYR (Cranmer et al. 2007) is a one-dimensional magnetohydrodynamics code that includes Alfven wave generation and reflection and the resulting turbulent heating to accelerate solar wind in open flux tubes. We present the ZEPHYR output for a wide range of magnetic field geometries to show the effect of the magnetic field profiles on wind properties. We also investigate the competing acceleration mechanisms found in ZEPHYR to determine the relative importance of increased gas pressure from turbulent heating and the separate pressure source from the Alfven waves. To do so, we developed a code that will become publicly available for solar wind prediction. This code, TEMPEST, provides an outflow solution based on only one input: the magnetic field strength as a function of height above the photosphere. It uses correlations found in ZEPHYR between the magnetic field strength at the source surface and the temperature profile of the outflow solution to compute the wind speed profile based on the increased gas pressure from turbulent heating. With this initial solution, TEMPEST then adds in the Alfven wave pressure term to the modified Parker equation and iterates to find a stable solution for the wind speed. This code, therefore, can make predictions of the wind speeds that will be observed at 1 AU based on extrapolations from magnetogram data, providing a useful tool for empirical forecasting of the sol! ar wind.

Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

DOEpatents

Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

2015-12-08

A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

Modelling the 2013 Typhoon Haiyan storm surge: Effect of waves, offshore winds, tide phase, and translation speed

NASA Astrophysics Data System (ADS)

Bilgera, P. H. T.

2015-12-01

Super Typhoon Haiyan, with wind speeds exceeding 300 km h-1 (160 knots) generated a storm surge in San Pedro Bay reaching heights of more than 6m in Tacloban City. Delft Dashboard (DDB), an open-source standalone Matlab based graphical user interface linked to the FLOW and WAVE modeling software of Deltares, was used to develop a coupled flow and wave storm surge model to understand the Typhoon Haiyan storm surge development and propagation. Various experiments were designed to determine the effect of waves, the occurrence of offshore winds prior to the surge, tidal phase, and typhoon translation speed on the surge height. Wave coupling decreased the surge height by about 0.5m probably due to energy dissipation from white capping, bottom friction, and depth-induced breaking. Offshore-directed winds before the arrival of the storm eye resulted to receding of the water level in San Pedro and Cancabato Bay, corroborated by eyewitness and tide gauge data. The experiment wherein the offshore winds were removed resulted to no water receding and a surge with a smaller and gentler surge front, pointing to the importance of the initial water level drawdown in contributing to the destructive power of the wave front. With regard to tides, the effect in Tacloban was actually neither linear nor additive to the surge, with higher surge coincident to low tides and lower surge coincident to high tides. Lastly, the model run with typhoon having a slower translation speed than Haiyan was found to generate higher surges.

Modelling the 2013 Typhoon Haiyan Storm Surge: Effect of Waves, Offshore Winds, Tide Phase, and Translation Speed

NASA Astrophysics Data System (ADS)

Bilgera, P. H. T.; Villanoy, C.; Cabrera, O.

2016-02-01

Super Typhoon Haiyan, with wind speeds exceeding 300 km h-1 (160 knots) generated a storm surge in San Pedro Bay reaching heights of more than 6m in Tacloban City. Delft Dashboard (DDB), an open-source standalone Matlab based graphical user interface linked to the FLOW and WAVE modeling software of Deltares, was used to develop a coupled flow and wave storm surge model to understand the Typhoon Haiyan storm surge development and propagation. Various experiments were designed to determine the effect of waves, the occurrence of offshore winds prior to the surge, tidal phase, and typhoon translation speed on the surge height. Wave coupling decreased the surge height by about 0.5m probably due to energy dissipation from white capping, bottom friction, and depth-induced breaking. Offshore-directed winds before the arrival of the storm eye resulted to receding of the water level in San Pedro and Cancabato Bay, corroborated by eyewitness and tide gauge data. The experiment wherein the offshore winds were removed resulted to no water receding and a surge with a smaller and gentler surge front, pointing to the importance of the initial water level drawdown in contributing to the destructive power of the wave front. With regard to tides, the effect in Tacloban was actually neither linear nor additive to the surge, with higher surge coincident to low tides and lower surge coincident to high tides. Lastly, the model run with typhoon having a slower translation speed than Haiyan was found to generate higher surges.

Speed kills: ineffective avian escape responses to oncoming vehicles

PubMed Central

DeVault, Travis L.; Blackwell, Bradley F.; Seamans, Thomas W.; Lima, Steven L.; Fernández-Juricic, Esteban

2015-01-01

Animal–vehicle collisions cause high levels of vertebrate mortality worldwide, and what goes wrong when animals fail to escape and ultimately collide with vehicles is not well understood. We investigated alert and escape behaviours of captive brown-headed cowbirds (Molothrus ater) in response to virtual vehicle approaches of different sizes and at speeds ranging from 60 to 360 km h−1. Alert and flight initiation distances remained similar across vehicle speeds, and accordingly, alert and flight initiation times decreased at higher vehicle speeds. Thus, avoidance behaviours in cowbirds appeared to be based on distance rather than time available for escape, particularly at 60–150 km h−1; however, at higher speeds (more than or equal to 180 km h−1) no trend in response behaviour was discernible. As vehicle speed increased, cowbirds did not have enough time to assess the approaching vehicle, and cowbirds generally did not initiate flight with enough time to avoid collision when vehicle speed exceeded 120 km h−1. Although potentially effective for evading predators, the decision-making process used by cowbirds in our study appears maladaptive in the context of avoiding fast-moving vehicles. Our methodological approach and findings provide a framework to assess how novel management strategies could affect escape rules, and the sensory and cognitive abilities animals use to avoid vehicle collisions. PMID:25567648

Recovery Systems Design Guide

DTIC Science & Technology

1978-12-01

analysis. retrieval parachute concepts are being investigated. The development of recovery systems for fast flying, possible out-of-control missiles proved...system. 21 •, . , r, _ . .. , . " , , . : . .. . " . , ,- Reference 32 suggests certain applications (speed/ Fast Opening. An emergency escape...operation, physiological aspect of flying and escape. fast parachute opening., Low Rate of Descent. A sea level rate of descent low parachute opening

Smooth pursuitlike eye movements evoked by microstimulation in macaque nucleus reticularis tegmenti pontis.

PubMed

Yamada, T; Suzuki, D A; Yee, R D

1996-11-01

1. Smooth pursuitlike eye movements were evoked with low current microstimulation delivered to rostral portions of the nucleus reticularis tegmenti pontis (rNRTP) in alert macaques. Microstimulation sites were selected by the observation of modulations in single-cell firing rates that were correlated with periodic smoothpursuit eye movements. Current intensities ranged from 10 to 120 microA and were routinely < 40 microA. Microstimulation was delivered either in the dark with no fixation, 100 ms after a fixation target was extinguished, or during maintained fixation of a stationary or moving target. Evoked eye movements also were studied under open-loop conditions with the target image stabilized on the retina. 2. Eye movements evoked in the absence of a target rapidly accelerated to a constant velocity that was maintained for the duration of the microstimulation. Evoked eye speeds ranged from 3.7 to 23 deg/s and averaged 11 deg/s. Evoked eye speed appeared to be linearly related to initial eye position with a sensitivity to initial eye position that averaged 0.23 deg.s-1.deg-1. While some horizontal and oblique smooth eye movements were elicited, microstimulation resulted in upward eye movements in 89% of the sites. 3. Evoked eye speed was found to be dependent on microstimulation pulse frequency and current intensity. Within limits, evoked eye speed increased with increases in stimulation frequency or current intensity. For stimulation frequencies < 300-400 Hz, only smooth pursuit-like eye movements were evoked. At higher stimulation frequencies, accompanying saccades consistently were elicited. 4. Feedback of retinal image motion interacted with the evoked eye movements to decrease eye speed if the visual motion was in the opposite direction as the evoked, pursuit-like eye movements. 5. The results implicate rNRTP as part of the neuronal substrate that controls smooth-pursuit eye movements. NRTP appears to be divided functionally into a rostral, pursuit-related portion and a caudal, saccade-related area. rNRTP is a component of a corticopontocerebellar circuit that presumably involves the pursuit area of the frontal eye field and that parallels the middle and medial superior temporal cerebral cortical/dorsalateral pontine nucleus (MT/MST-DLPN-cerebellum) pathway known to be involved also with regulating smooth-pursuit eye movements.

42 CFR 435.1205 - Alignment with exchange initial open enrollment period.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 4 2013-10-01 2013-10-01 false Alignment with exchange initial open enrollment... exchange initial open enrollment period. (a) Definitions. For purposes of this section— Eligibility based... 435.119, 435.218 and 435.603. (b) Medicaid agency responsibilities to achieve coordinated open...

Open Governance in Higher Education: Extending the Past to the Future

ERIC Educational Resources Information Center

Masson, Patrick

2011-01-01

Open educational resources, open content, open access, open research, open courseware--all of these open initiatives share, and benefit from, a vision of access and a collaborative framework that often result in improved outcomes. Many of these open initiatives have gained adoption within higher education and are now serving in mission-critical…

Hyperspectral-Augmented Target Tracking

DTIC Science & Technology

2008-03-01

detectable velocity ( MDV ) of 1.5m/s. After several seconds, the vehicles depart heading in the same di- rection, but this time, the top vehicle speeds up... vehicles begin to speed up ( MDV > 1.5m/s), the tracker once again initiates each track using the class ID of the nearest vehicle , effectively swapping the...Fig. 4.5(b)). After both vehicles speed up to an MDV > 1.5m/s, the tracker initiates each track using the class ID of the nearest vehicle , “re-assigning

6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ...

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

6. GOVERNOR AND SPEED CONTROL MECHANISMS TANK, AT LEFT AN ACCUMULATOR TANK WHICH STORE AIR PRESSURE TO OPEN GATES AND GET GENERATOR STARTED. LARGE TANK AT RIGHT IS THE MAIN GUARD VALVE FOR THE GENERATOR - Los Angeles Aqueduct, Haiwee Power Plant, Los Angeles, Los Angeles County, CA

Comparison of pressure-controlled provocation discography using automated versus manual syringe pump manometry in patients with chronic low back pain.

PubMed

Derby, Richard; Lee, Sang Hoon; Lee, Jeong-Eun; Lee, Sang-Heon

2011-01-01

The study compares the rate of positive discograms using an automated versus a manual pressure-controlled injection devise and compares the pressure and volume values at various pressures and initial evoked pain and 6/10 or greater evoked pain. A retrospective study prospectively collected patient study data used in a prior prospective study and with prospectively collected data which is routinely collected per our institutional standardized audit protocol. Two custom-built disc manometers (automated injection speed control; manual injection speed control) were sequentially employed during provocation discography in 510 discs of 151 consecutive patients. Two hundred thirty-seven discs of 67 patients with chronic low back pain were evaluated using the automated manometer (automated group) and 273 discs of 84 patients were evaluated with a manual manometer (manual group). No significant differences in positive discogram rates were found between the automated and manual groups (32.1% vs 32.6% per disc, respectively, P>0.05). No significant differences in low-pressure positive discogram rates were found (16.0% vs 15.0% per disc, automated group versus manual group, respectively, P>0.05). However, there were significantly increased volumes and lower pressures at initial and "bad" pain provocation. The study results found equivalent positive discogram rates following a series of pressure-controlled discography using either an automated or manual pressure devise. There were, however significant increases in volume at both initial onset of evoked pain and at 6/10 pain when using the automated injection devise that may have caused the observed lower opening pressure and lower pressure values at initial evoked pain. Assuming increased volumes are innocuous, automated injection is inherently more controlled and may better reduce unintended and often unrecorded spurious high dynamic pressure peaks thereby reducing conscious and unconscious operator bias. Wiley Periodicals, Inc.

Measurements of droplet velocity and size downstream of the moving valves of a four-valve engine with manifold injection, operated under isothermal steady suction conditions

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

Posylkin, M.; Taylor, A.M.K.P.; Whitelaw, J.H.

The four-valve head of a VTEC engine was mounted on an open cylinder and the valves and fuel injection system operated as in the engine with a rotational speed of 1,200 rpm. Local measurements of droplet characteristics were obtained with a phase-Doppler velocimeter and iso-octane injected over 5 ms intervals, corresponding to 36 crank angle degrees, with manifold depression of 20 mbar. The results show that most of the fuel droplets were located close to the liner and on the side of the cylinder adjacent to the exhaust valves. In the plane of the measurement, 10 mm below TDC, themore » liquid flux diminished as the initiation of injection was advanced before opening of the inlet valves. With injection with the inlet valves closed, there were two waves of droplets, one from each of the two valves and separated by 60 deg CA and both with the Sauter mean diameter of about 120 {micro}m. With injection with the inlet valves open, most of the droplets emerged from the main inlet valve and with Sauter mean diameters of about 50 {micro}m, smaller than those of the unconfined spray.« less

Dissipation and Residues of Pyrethrins in Leaf Lettuce under Greenhouse and Open Field Conditions

PubMed Central

Pan, Lixiang; Feng, Xiaoxiao; Zhang, Hongyan

2017-01-01

Pyrethrins are nowadays widely used for prevention and control of insects in leaf lettuce. However, there is a concern about the pesticide residue in leaf lettuce. A reliable analytical method for determination of pyrethrins (pyrethrin—and П, cinerin І and П, and jasmolin І and П) in leaf lettuce was developed by using gas chromatography–mass spectrometry (GC–MS). Recoveries of pyrethrins in leaf lettuce at three spiking levels were 99.4–104.0% with relative standard deviations of 0.9–3.1% (n = 5). Evaluation of dissipation and final residues of pyrethrins in leaf lettuce were determined at six different locations, including the open field, as well as under greenhouse conditions. The initial concentration of pyrethrins in greenhouse (0.57 mg/kg) was higher than in open field (0.25 mg/kg) and the half-life for pyrethrins disappearance in field lettuce (0.7 days) was less than that greenhouse lettuce (1.1 days). Factors such as rainfall, solar radiation, wind speed, and crop growth rate are likely to have caused these results. The final residue in leaf lettuce was far below the maximum residue limits (MRLs) (1 mg/kg established by the European Union (EU), Australia, Korea, Japan). PMID:28754023

Tip clearance effects on loads and performances of semi-open impeller centrifugal pumps at different specific speeds

NASA Astrophysics Data System (ADS)

Boitel, G.; Fedala, D.; Myon, N.

2016-11-01

Relevant industrial standards or customer's specifications could strictly forbid any device adjusting the axial rotor/stator position, so that tip clearance between semi-open impeller and casing might become a result of the pump machining tolerances and assembling process, leading to big tip clearance variations compared to its nominal value. Consequently, large disparities of global performances (head, power, efficiency) and axial loads are observed with high risk of both specifications noncompliance and bearing damages. This work aims at quantifying these variations by taking into account tip clearance value and pump specific speed. Computational Fluid Dynamics is used to investigate this phenomenon by means of steady simulations led on a semi-open centrifugal pump numerical model including secondary flows, based on a k-omega SST turbulence model. Four different specific speed pump sizes are simulated (from 8 to 50, SI units), with three tip clearances for each size on a wide flow range (from 40% to 120% of the best efficiency point). The numerical results clearly show that head, power and efficiency increase as the tip clearance decreases for the whole flow range. This effect is more significant when the specific speed is low. Meanwhile, the resulting axial thrust on the impeller is very sensitive to the tip clearance and can even lead to direction inversion.

GOTCHA

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

Poliakoff, David; Legendre, Matt

2017-03-29

GOTCHA is a runtime API intercepting function calls between shared libraries. It is intended to be used by HPC Tools (i.e., performance analysis tools like Open/SpeedShop, HPCToolkit, TAU, etc.). 2:18 PMThese other tools can use Gotch to intercept interesting functions, such as MPI functions, and collect performance metrics about those functions. We intend for this to be open-source software that gets adopted by other open-s0urse tools that are used at LLNL.

[Microclimate and comfortable degree of Shanghai urban open spaces in summer].

PubMed

Cao, Dan; Zhou, Li-chen; Mao, Yi-wei; Li, Yin; Liu, Yi-ning; Wang, Tian-hou

2008-08-01

Based on the observation data of air temperature, relative humidity, wind speed, and solar radiation from May to August 2006, the regulation effects of five types of open spaces (square, fountain, grassplot, corridor, and woodland) in Shanghai urban districts on the microclimate were analyzed, and discomfort index (DI) was introduced to evaluate the effects of these five types of open spaces on human body' s comfortable degree. The results showed that there existed definite differences in the air temperature and relative humidity among the open spaces, with the mean temperature decreased in the order of square > grassplot > fountain > corridor > woodland, and the mean relative humidity decreased in the order of woodland > corridor > fountain > grassplot > square. The area of the square, the wind speed and direction near the fountain, the grass species on the grass-plot, the width and tree coverage of the corridor, and the tree coverage and canopy height of the woodland had significant correlations with the microclimate parameters of corresponding open spaces. Comparing with other three types of open spaces, woodland and corridor had better regulation effects on the microclimate via shading, decreasing air temperature, and increasing relative humidity.

Open innovation: Towards sharing of data, models and workflows.

PubMed

Conrado, Daniela J; Karlsson, Mats O; Romero, Klaus; Sarr, Céline; Wilkins, Justin J

2017-11-15

Sharing of resources across organisations to support open innovation is an old idea, but which is being taken up by the scientific community at increasing speed, concerning public sharing in particular. The ability to address new questions or provide more precise answers to old questions through merged information is among the attractive features of sharing. Increased efficiency through reuse, and increased reliability of scientific findings through enhanced transparency, are expected outcomes from sharing. In the field of pharmacometrics, efforts to publicly share data, models and workflow have recently started. Sharing of individual-level longitudinal data for modelling requires solving legal, ethical and proprietary issues similar to many other fields, but there are also pharmacometric-specific aspects regarding data formats, exchange standards, and database properties. Several organisations (CDISC, C-Path, IMI, ISoP) are working to solve these issues and propose standards. There are also a number of initiatives aimed at collecting disease-specific databases - Alzheimer's Disease (ADNI, CAMD), malaria (WWARN), oncology (PDS), Parkinson's Disease (PPMI), tuberculosis (CPTR, TB-PACTS, ReSeqTB) - suitable for drug-disease modelling. Organized sharing of pharmacometric executable model code and associated information has in the past been sparse, but a model repository (DDMoRe Model Repository) intended for the purpose has recently been launched. In addition several other services can facilitate model sharing more generally. Pharmacometric workflows have matured over the last decades and initiatives to more fully capture those applied to analyses are ongoing. In order to maximize both the impact of pharmacometrics and the knowledge extracted from clinical data, the scientific community needs to take ownership of and create opportunities for open innovation. Copyright © 2017 Elsevier B.V. All rights reserved.

Visual control of flight speed in Drosophila melanogaster.

PubMed

Fry, Steven N; Rohrseitz, Nicola; Straw, Andrew D; Dickinson, Michael H

2009-04-01

Flight control in insects depends on self-induced image motion (optic flow), which the visual system must process to generate appropriate corrective steering maneuvers. Classic experiments in tethered insects applied rigorous system identification techniques for the analysis of turning reactions in the presence of rotating pattern stimuli delivered in open-loop. However, the functional relevance of these measurements for visual free-flight control remains equivocal due to the largely unknown effects of the highly constrained experimental conditions. To perform a systems analysis of the visual flight speed response under free-flight conditions, we implemented a 'one-parameter open-loop' paradigm using 'TrackFly' in a wind tunnel equipped with real-time tracking and virtual reality display technology. Upwind flying flies were stimulated with sine gratings of varying temporal and spatial frequencies, and the resulting speed responses were measured from the resulting flight speed reactions. To control flight speed, the visual system of the fruit fly extracts linear pattern velocity robustly over a broad range of spatio-temporal frequencies. The speed signal is used for a proportional control of flight speed within locomotor limits. The extraction of pattern velocity over a broad spatio-temporal frequency range may require more sophisticated motion processing mechanisms than those identified in flies so far. In Drosophila, the neuromotor pathways underlying flight speed control may be suitably explored by applying advanced genetic techniques, for which our data can serve as a baseline. Finally, the high-level control principles identified in the fly can be meaningfully transferred into a robotic context, such as for the robust and efficient control of autonomous flying micro air vehicles.

Effects of Vehicle Speed on Flight Initiation by Turkey Vultures: Implications for Bird-Vehicle Collisions

PubMed Central

DeVault, Travis L.; Blackwell, Bradley F.; Seamans, Thomas W.; Lima, Steven L.; Fernández-Juricic, Esteban

2014-01-01

The avoidance of motorized vehicles is a common challenge for birds in the modern world. Birds appear to rely on antipredator behaviors to avoid vehicles, but modern vehicles (automobiles and aircraft) are faster than natural predators. Thus, birds may be relatively ill-equipped, in terms of sensory capabilities and behaviors, to avoid vehicles. We examined the idea that birds may be unable to accurately assess particularly high speeds of approaching vehicles, which could contribute to miscalculations in avoidance behaviors and ultimately cause collisions. We baited turkey vultures (Cathartes aura) to roads with animal carcasses and measured flight initiation distance and effective time-to-collision in response to a truck driving directly towards vultures from a starting distance of 1.13 km and at one of three speeds: 30, 60, or 90 kph (no vultures were struck). Flight initiation distance of vultures increased by a factor of 1.85 as speed increased from 30 to 90 kph. However, for 90-kph approaches there was no clear trend in flight initiation distance across replicates: birds appeared equally likely to initiate escape behavior at 40 m as at 220 m. Time-to-collision decreased by a factor of 0.62 with approach speeds from 30 to 90 kph. Also, at 90 kph, four vehicle approaches (17%) resulted in near collisions with vultures (time-to-collision ≤1.7 s), compared to none during 60 kph approaches and one during 30 kph approaches (4%). Our findings suggest that antipredator behaviors in turkey vultures, particularly stimulus processing and response, might not be well tuned to vehicles approaching at speeds ≥90 kph. The possible inability of turkey vultures to react appropriately to high-speed vehicles could be common among birds, and might represent an important determinant of bird-vehicle collisions. PMID:24503622

Turbulent aerosol fluxes over the Arctic Ocean: 2. Wind-driven sources from the sea

NASA Astrophysics Data System (ADS)

Nilsson, E. D.; Rannik, Ü.; Swietlicki, E.; Leck, C.; Aalto, P. P.; Zhou, J.; Norman, M.

2001-12-01

An eddy-covariance flux system was successfully applied over open sea, leads and ice floes during the Arctic Ocean Expedition in July-August 1996. Wind-driven upward aerosol number fluxes were observed over open sea and leads in the pack ice. These particles must originate from droplets ejected into the air at the bursting of small air bubbles at the water surface. The source flux F (in 106 m-2 s-1) had a strong dependency on wind speed, log>(F>)=0.20U¯-1.71 and 0.11U¯-1.93, over the open sea and leads, respectively (where U¯ is the local wind speed at about 10 m height). Over the open sea the wind-driven aerosol source flux consisted of a film drop mode centered at ˜100 nm diameter and a jet drop mode centered at ˜1 μm diameter. Over the leads in the pack ice, a jet drop mode at ˜2 μm diameter dominated. The jet drop mode consisted of sea-salt, but oxalate indicated an organic contribution, and bacterias and other biogenic particles were identified by single particle analysis. Particles with diameters less than -100 nm appear to have contributed to the flux, but their chemical composition is unknown. Whitecaps were probably the bubble source at open sea and on the leads at high wind speed, but a different bubble source is needed in the leads owing to their small fetch. Melting of ice in the leads is probably the best candidate. The flux over the open sea was of such a magnitude that it could give a significant contribution to the condensation nuclei (CCN) population. Although the flux from the leads were roughly an order of magnitude smaller and the leads cover only a small fraction of the pack ice, the local source may till be important for the CCN population in Arctic fogs. The primary marine aerosol source will increase both with increased wind speed and with decreased ice fraction and extent. The local CCN production may therefore increase and influence cloud or fog albedo and lifetime in response to greenhouse warming in the Arctic Ocean region.

High-speed rupture during the initiation of the 2015 Bonin Islands deep earthquake

NASA Astrophysics Data System (ADS)

Zhan, Z.; Ye, L.; Shearer, P. M.; Lay, T.; Kanamori, H.

2015-12-01

Among the long-standing questions on how deep earthquakes rupture, the nucleation phase of large deep events is one of the most puzzling parts. Resolving the rupture properties of the initiation phase is difficult to achieve with far-field data because of the need for accurate corrections for structural effects on the waveforms (e.g., attenuation, scattering, and site effects) and alignment errors. Here, taking the 2015 Mw 7.9 Bonin Islands earthquake (depth = 678 km) as an example, we jointly invert its far-field P waves at multiple stations for the average rupture speed during the first second of the event. We use waveforms from a closely located aftershock as empirical Green's functions, and correct for possible differences in focal mechanisms and waveform misalignments with an iterative approach. We find that the average initial rupture speed is over 5 km/s, significantly higher than the average rupture speed of 3 km/s later in the event. This contrast suggests that rupture speeds of deep earthquakes can be highly variable during individual events and may define different stages of rupture, potentially with different mechanisms.

The air bubble entrapped under a drop impacting on a solid surface

NASA Astrophysics Data System (ADS)

Thoroddsen, S. T.; Etoh, T. G.; Takehara, K.; Ootsuka, N.; Hatsuki, Y.

2005-12-01

We present experimental observations of the disk of air caught under a drop impacting onto a solid surface. By imaging the impact through an acrylic plate with an ultra-high-speed video camera, we can follow the evolution of the air disk as it contracts into a bubble under the centre of the drop. The initial size and contraction speed of the disk were measured for a range of impact Weber and Reynolds numbers. The size of the initial disk is related to the bottom curvature of the drop at the initial contact, as measured in free-fall. The initial contact often leaves behind a ring of micro-bubbles, marking its location. The air disk contracts at a speed comparable to the corresponding air disks caught under a drop impacting onto a liquid surface. This speed also seems independent of the wettability of the liquid, which only affects the azimuthal shape of the contact line. For some impact conditions, the dynamics of the contraction leaves a small droplet at the centre of the bubble. This arises from a capillary wave propagating from the edges of the contracting disk towards the centre. As the wave converges its amplitude grows until it touches the solid substrate, thereby pinching off the micro-droplet at the plate, in the centre of the bubble. The effect of increasing liquid viscosity is to slow down the contraction speed and to produce a more irregular contact line leaving more micro-bubbles along the initial ring.

Fast parallel image registration on CPU and GPU for diagnostic classification of Alzheimer's disease

PubMed Central

Shamonin, Denis P.; Bron, Esther E.; Lelieveldt, Boudewijn P. F.; Smits, Marion; Klein, Stefan; Staring, Marius

2013-01-01

Nonrigid image registration is an important, but time-consuming task in medical image analysis. In typical neuroimaging studies, multiple image registrations are performed, i.e., for atlas-based segmentation or template construction. Faster image registration routines would therefore be beneficial. In this paper we explore acceleration of the image registration package elastix by a combination of several techniques: (i) parallelization on the CPU, to speed up the cost function derivative calculation; (ii) parallelization on the GPU building on and extending the OpenCL framework from ITKv4, to speed up the Gaussian pyramid computation and the image resampling step; (iii) exploitation of certain properties of the B-spline transformation model; (iv) further software optimizations. The accelerated registration tool is employed in a study on diagnostic classification of Alzheimer's disease and cognitively normal controls based on T1-weighted MRI. We selected 299 participants from the publicly available Alzheimer's Disease Neuroimaging Initiative database. Classification is performed with a support vector machine based on gray matter volumes as a marker for atrophy. We evaluated two types of strategies (voxel-wise and region-wise) that heavily rely on nonrigid image registration. Parallelization and optimization resulted in an acceleration factor of 4–5x on an 8-core machine. Using OpenCL a speedup factor of 2 was realized for computation of the Gaussian pyramids, and 15–60 for the resampling step, for larger images. The voxel-wise and the region-wise classification methods had an area under the receiver operator characteristic curve of 88 and 90%, respectively, both for standard and accelerated registration. We conclude that the image registration package elastix was substantially accelerated, with nearly identical results to the non-optimized version. The new functionality will become available in the next release of elastix as open source under the BSD license. PMID:24474917

Chain representations of Open Quantum Systems and Lieb-Robinson like bounds for the dynamics

NASA Astrophysics Data System (ADS)

Woods, Mischa

2013-03-01

This talk is concerned with the mapping of the Hamiltonian of open quantum systems onto chain representations, which forms the basis for a rigorous theory of the interaction of a system with its environment. This mapping progresses as an interaction which gives rise to a sequence of residual spectral densities of the system. The rigorous mathematical properties of this mapping have been unknown so far. Here we develop the theory of secondary measures to derive an analytic, expression for the sequence solely in terms of the initial measure and its associated orthogonal polynomials of the first and second kind. These mappings can be thought of as taking a highly nonlocal Hamiltonian to a local Hamiltonian. In the latter, a Lieb-Robinson like bound for the dynamics of the open quantum system makes sense. We develop analytical bounds on the error to observables of the system as a function of time when the semi-infinite chain in truncated at some finite length. The fact that this is possible shows that there is a finite ``Speed of sound'' in these chain representations. This has many implications of the simulatability of open quantum systems of this type and demonstrates that a truncated chain can faithfully reproduce the dynamics at shorter times. These results make a significant and mathematically rigorous contribution to the understanding of the theory of open quantum systems; and pave the way towards the efficient simulation of these systems, which within the standard methods, is often an intractable problem. EPSRC CDT in Controlled Quantum Dynamics, EU STREP project and Alexander von Humboldt Foundation

Data Architecture in an Open Systems Environment.

ERIC Educational Resources Information Center

Bernbom, Gerald; Cromwell, Dennis

1993-01-01

The conceptual basis for structured data architecture, and its integration with open systems technology at Indiana University, are described. Key strategic goals guiding these efforts are discussed: commitment to improved data access; migration to relational database technology, and deployment of a high-speed, multiprotocol network; and…

Direct measurement of the speed of sound using a microphone and a speaker

NASA Astrophysics Data System (ADS)

Gómez-Tejedor, José A.; Castro-Palacio, Juan C.; Monsoriu, Juan A.

2014-05-01

We present a simple and accurate experiment to obtain the speed of sound in air using a conventional speaker and a microphone connected to a computer. A free open source digital audio editor and recording computer software application allows determination of the time-of-flight of the wave for different distances, from which the speed of sound is calculated. The result is in very good agreement with the reported value in the literature.

Safety Relevant Observations on the ICE High Speed Train

DOT National Transportation Integrated Search

1991-07-01

The safety of high speed rail technology proposed for possible application in the United States is of concern to the Federal Railroad Administration. This report, one in a series of reports planned for high speed rail technologies presents an initial...

Comparing the floquet stability of open and breathing fatigue cracks in an overhung rotordynamic system

NASA Astrophysics Data System (ADS)

Varney, Philip; Green, Itzhak

2017-11-01

Rotor cracks represent an uncommon but serious threat to rotating machines and must be detected early to avoid catastrophic machine failure. An important aspect of analyzing rotor cracks is understanding their influence on the rotor stability. It is well-known that the extent of rotor instability versus shaft speed is exacerbated by deeper cracks. Consequently, crack propagation can eventually result in an unstable response even if the shaft speed remains constant. Most previous investigations of crack-induced rotor instability concern simple Jeffcott rotors. This work advances the state-of-the-art by (a) providing a novel inertial-frame model of an overhung rotor, and (b) assessing the stability of the cracked overhung rotor using Floquet stability analysis. The rotor Floquet stability analysis is performed for both an open crack and a breathing crack, and conclusions are drawn regarding the importance of appropriately selecting the crack model. The rotor stability is analyzed versus crack depth, external viscous damping ratio, and rotor inertia. In general, this work concludes that the onset of instability occurs at lower shaft speeds for thick rotors, lower viscous damping ratios, and deeper cracks. In addition, when comparing commensurate cracks, the breathing crack is shown to induce more regions of instability than the open crack, though the open crack generally predicts an unstable response for shallower cracks than the breathing crack. Keywords: rotordynamics, stability, rotor cracks.

NASA Langley Low Speed Aeroacoustic Wind Tunnel: Background Noise and Flow Survey Results Prior to FY05 Construction of Facilities Modifications

NASA Technical Reports Server (NTRS)

Booth, Earl R., Jr.; Henderson, Brenda S.

2005-01-01

The NASA Langley Research Center Low Speed Aeroacoustic Wind Tunnel is a premier facility for model-scale testing of jet noise reduction concepts at realistic flow conditions. However, flow inside the open jet test section is less than optimum. A Construction of Facilities project, scheduled for FY 05, will replace the flow collector with a new design intended to reduce recirculation in the open jet test section. The reduction of recirculation will reduce background noise levels measured by a microphone array impinged by the recirculation flow and will improve flow characteristics in the open jet tunnel flow. In order to assess the degree to which this modification is successful, background noise levels and tunnel flow are documented, in order to establish a baseline, in this report.

SPLASSH: Open source software for camera-based high-speed, multispectral in-vivo optical image acquisition

PubMed Central

Sun, Ryan; Bouchard, Matthew B.; Hillman, Elizabeth M. C.

2010-01-01

Camera-based in-vivo optical imaging can provide detailed images of living tissue that reveal structure, function, and disease. High-speed, high resolution imaging can reveal dynamic events such as changes in blood flow and responses to stimulation. Despite these benefits, commercially available scientific cameras rarely include software that is suitable for in-vivo imaging applications, making this highly versatile form of optical imaging challenging and time-consuming to implement. To address this issue, we have developed a novel, open-source software package to control high-speed, multispectral optical imaging systems. The software integrates a number of modular functions through a custom graphical user interface (GUI) and provides extensive control over a wide range of inexpensive IEEE 1394 Firewire cameras. Multispectral illumination can be incorporated through the use of off-the-shelf light emitting diodes which the software synchronizes to image acquisition via a programmed microcontroller, allowing arbitrary high-speed illumination sequences. The complete software suite is available for free download. Here we describe the software’s framework and provide details to guide users with development of this and similar software. PMID:21258475

Wind-sea surface temperature-sea ice relationship in the Chukchi-Beaufort Seas during autumn

NASA Astrophysics Data System (ADS)

Zhang, Jing; Stegall, Steve T.; Zhang, Xiangdong

2018-03-01

Dramatic climate changes, especially the largest sea ice retreat during September and October, in the Chukchi-Beaufort Seas could be a consequence of, and further enhance, complex air-ice-sea interactions. To detect these interaction signals, statistical relationships between surface wind speed, sea surface temperature (SST), and sea ice concentration (SIC) were analyzed. The results show a negative correlation between wind speed and SIC. The relationships between wind speed and SST are complicated by the presence of sea ice, with a negative correlation over open water but a positive correlation in sea ice dominated areas. The examination of spatial structures indicates that wind speed tends to increase when approaching the ice edge from open water and the area fully covered by sea ice. The anomalous downward radiation and thermal advection, as well as their regional distribution, play important roles in shaping these relationships, though wind-driven sub-grid scale boundary layer processes may also have contributions. Considering the feedback loop involved in the wind-SST-SIC relationships, climate model experiments would be required to further untangle the underlying complex physical processes.

Simulation Speed Analysis and Improvements of Modelica Models for Building Energy Simulation

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

Jorissen, Filip; Wetter, Michael; Helsen, Lieve

This paper presents an approach for speeding up Modelica models. Insight is provided into how Modelica models are solved and what determines the tool’s computational speed. Aspects such as algebraic loops, code efficiency and integrator choice are discussed. This is illustrated using simple building simulation examples and Dymola. The generality of the work is in some cases verified using OpenModelica. Using this approach, a medium sized office building including building envelope, heating ventilation and air conditioning (HVAC) systems and control strategy can be simulated at a speed five hundred times faster than real time.

Ultrafast shock compression of an oxygen-balanced mixture of nitromethane and hydrogen peroxide.

PubMed

Armstrong, Michael R; Zaug, Joseph M; Grant, Christian D; Crowhurst, Jonathan C; Bastea, Sorin

2014-08-14

We apply ultrafast optical interferometry to measure the Hugoniot of an oxygen-balanced mixture of nitromethane and hydrogen peroxide (NM/HP) and compare with Hugoniot data for pure nitromethane (NM) and a 90% hydrogen peroxide/water mixture (HP), as well as theoretical predictions. We observe a 2.1% percent mean pairwise difference between the measured shockwave speed (at the measured piston speed) in unreacted NM/HP and the corresponding "universal" liquid Hugoniot, which is larger than the average standard deviation of our data, 1.4%. Unlike the Hugoniots of both HP and NM, in which measured shock speeds deviate to values greater than the unreacted Hugoniot for piston speeds larger than the respective reaction thresholds, in the NM/HP mixture we observe shock speed deviations to values lower than the unreacted Hugoniot well below the von Neumann pressure (≈28 GPa). Although the trend should reverse for high enough piston speeds, the initial behavior is unexpected. Possible explanations range from mixing effects to a complex index of refraction in the reacted solution. If this is indeed a signature of chemical initiation, it would suggest that the process may not be kinetically limited (on a ~100 ps time scale) between the initiation threshold and the von Neumann pressure.

Homologous and cannibalistic coronal mass ejections from twisted magnetic flux rope simulations

NASA Astrophysics Data System (ADS)

Chatterjee, Piyali; Fan, Yuhong

We present results from magnetohydrodynamic simulations of the development of homologous sequence of coronal mass ejections (CMEs) and demonstrate their so-called cannibalistic behavior. These CMEs originate from the repeated formations and partial eruptions of kink unstable flux ropes as a result of continued emergence of a twisted flux rope across the lower boundary into a pre-existing coronal potential arcade field. Our simulation shows that a CME erupting into the open magnetic field created by a preceding CME has a higher speed. The second of the three successive CMEs in one of the simulations is cannibalistic, catching up and merging with the first into a single fast CME before exiting the domain. All the CMEs including the leading merged CME, attained speeds of about 1000 km s-1 as they exit the domain. The reformation of a twisted flux rope after each CME eruption during the sustained flux emergence can naturally explain the X-ray observations of repeated reformations of sigmoids and "sigmoid-under-cusp" configurations at a low-coronal source of homologous CMEs. We also investigate the initiation mechanism and ejecta topology of these energetic CMEs as a function of the twist parameter of the flux rope.

mz5: space- and time-efficient storage of mass spectrometry data sets.

PubMed

Wilhelm, Mathias; Kirchner, Marc; Steen, Judith A J; Steen, Hanno

2012-01-01

Across a host of MS-driven-omics fields, researchers witness the acquisition of ever increasing amounts of high throughput MS data and face the need for their compact yet efficiently accessible storage. Addressing the need for an open data exchange format, the Proteomics Standards Initiative and the Seattle Proteome Center at the Institute for Systems Biology independently developed the mzData and mzXML formats, respectively. In a subsequent joint effort, they defined an ontology and associated controlled vocabulary that specifies the contents of MS data files, implemented as the newer mzML format. All three formats are based on XML and are thus not particularly efficient in either storage space requirements or read/write speed. This contribution introduces mz5, a complete reimplementation of the mzML ontology that is based on the efficient, industrial strength storage backend HDF5. Compared with the current mzML standard, this strategy yields an average file size reduction to ∼54% and increases linear read and write speeds ∼3-4-fold. The format is implemented as part of the ProteoWizard project and is available under a permissive Apache license. Additional information and download links are available from http://software.steenlab.org/mz5.

The giant acoustic atom - a single quantum system with a deterministic time delay

NASA Astrophysics Data System (ADS)

Guo, Lingzhen; Grimsmo, Arne; Frisk Kockum, Anton; Pletyukhov, Mikhail; Johansson, Göran

2017-04-01

We investigate the quantum dynamics of a single transmon qubit coupled to surface acoustic waves (SAWs) via two distant connection points. Since the acoustic speed is five orders of magnitude slower than the speed of light, the travelling time between the two connection points needs to be taken into account. Therefore, we treat the transmon qubit as a giant atom with a deterministic time delay. We find that the spontaneous emission of the system, formed by the giant atom and the SAWs between its connection points, initially follows a polynomial decay law instead of an exponential one, as would be the case for a small atom. We obtain exact analytical results for the scattering properties of the giant atom up to two-phonon processes by using a diagrammatic approach. The time delay gives rise to novel features in the reflection, transmission, power spectra, and second-order correlation functions of the system. Furthermore, we find the short-time dynamics of the giant atom for arbitrary drive strength by a numerically exact method for open quantum systems with a finite-time-delay feedback loop. L. G. acknowledges financial support from Carl-Zeiss Stiftung (0563-2.8/508/2).

40 CFR 202.20 - Standards for highway operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) measured on an open site with fast meter response at 50 feet from the centerline of lane of travel on highways with speed limits of 35 MPH or less; or 90 dB(A) measured on an open site with fast meter response..., acceleration or deceleration generates a sound level in excess of 83 dB(A) measured on an open site with fast...

40 CFR 202.20 - Standards for highway operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) measured on an open site with fast meter response at 50 feet from the centerline of lane of travel on highways with speed limits of 35 MPH or less; or 90 dB(A) measured on an open site with fast meter response..., acceleration or deceleration generates a sound level in excess of 83 dB(A) measured on an open site with fast...

40 CFR 202.20 - Standards for highway operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) measured on an open site with fast meter response at 50 feet from the centerline of lane of travel on highways with speed limits of 35 MPH or less; or 90 dB(A) measured on an open site with fast meter response..., acceleration or deceleration generates a sound level in excess of 83 dB(A) measured on an open site with fast...

40 CFR 202.20 - Standards for highway operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) measured on an open site with fast meter response at 50 feet from the centerline of lane of travel on highways with speed limits of 35 MPH or less; or 90 dB(A) measured on an open site with fast meter response..., acceleration or deceleration generates a sound level in excess of 83 dB(A) measured on an open site with fast...

40 CFR 202.20 - Standards for highway operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) measured on an open site with fast meter response at 50 feet from the centerline of lane of travel on highways with speed limits of 35 MPH or less; or 90 dB(A) measured on an open site with fast meter response..., acceleration or deceleration generates a sound level in excess of 83 dB(A) measured on an open site with fast...

Enhancing data utilization through adoption of cloud-based data architectures (Invited Paper 211869)

NASA Astrophysics Data System (ADS)

Kearns, E. J.

2017-12-01

A traditional approach to data distribution and utilization of open government data involves continuously moving those data from a central government location to each potential user, who would then utilize them on their local computer systems. An alternate approach would be to bring those users to the open government data, where users would also have access to computing and analytics capabilities that would support data utilization. NOAA's Big Data Project is exploring such an alternate approach through an experimental collaboration with Amazon Web Services, Google Cloud Platform, IBM, Microsoft Azure, and the Open Commons Consortium. As part of this ongoing experiment, NOAA is providing open data of interest which are freely hosted by the Big Data Project Collaborators, who provide a variety of cloud-based services and capabilities to enable utilization by data users. By the terms of the agreement, the Collaborators may charge for those value-added services and processing capacities to recover their costs to freely host the data and to generate profits if so desired. Initial results have shown sustained increases in data utilization from 2 to over 100 times previously-observed access patterns from traditional approaches. Significantly increased utilization speed as compared to the traditional approach has also been observed by NOAA data users who have volunteered their experiences on these cloud-based systems. The potential for implementing and sustaining the alternate cloud-based approach as part of a change in operational data utilization strategies will be discussed.

Acceleration of Radiance for Lighting Simulation by Using Parallel Computing with OpenCL

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

Zuo, Wangda; McNeil, Andrew; Wetter, Michael

2011-09-06

We report on the acceleration of annual daylighting simulations for fenestration systems in the Radiance ray-tracing program. The algorithm was optimized to reduce both the redundant data input/output operations and the floating-point operations. To further accelerate the simulation speed, the calculation for matrix multiplications was implemented using parallel computing on a graphics processing unit. We used OpenCL, which is a cross-platform parallel programming language. Numerical experiments show that the combination of the above measures can speed up the annual daylighting simulations 101.7 times or 28.6 times when the sky vector has 146 or 2306 elements, respectively.

Phase dependence of transport-aperture coordination variability reveals control strategy of reach-to-grasp movements.

PubMed

Rand, Miya K; Shimansky, Y P; Hossain, Abul B M I; Stelmach, George E

2010-11-01

Based on an assumption of movement control optimality in reach-to-grasp movements, we have recently developed a mathematical model of transport-aperture coordination (TAC), according to which the hand-target distance is a function of hand velocity and acceleration, aperture magnitude, and aperture velocity and acceleration (Rand et al. in Exp Brain Res 188:263-274, 2008). Reach-to-grasp movements were performed by young adults under four different reaching speeds and two different transport distances. The residual error magnitude of fitting the above model to data across different trials and subjects was minimal for the aperture-closure phase, but relatively much greater for the aperture-opening phase, indicating considerable difference in TAC variability between those phases. This study's goal is to identify the main reasons for that difference and obtain insights into the control strategy of reach-to-grasp movements. TAC variability within the aperture-opening phase of a single trial was found minimal, indicating that TAC variability between trials was not due to execution noise, but rather a result of inter-trial and inter-subject variability of motor plan. At the same time, the dependence of the extent of trial-to-trial variability of TAC in that phase on the speed of hand transport was sharply inconsistent with the concept of speed-accuracy trade-off: the lower the speed, the larger the variability. Conversely, the dependence of the extent of TAC variability in the aperture-closure phase on hand transport speed was consistent with that concept. Taking into account recent evidence that the cost of neural information processing is substantial for movement planning, the dependence of TAC variability in the aperture-opening phase on task performance conditions suggests that it is not the movement time that the CNS saves in that phase, but the cost of neuro-computational resources and metabolic energy required for TAC regulation in that phase. Thus, the CNS performs a trade-off between that cost and TAC regulation accuracy. It is further discussed that such trade-off is possible because, due to a special control law that governs optimal switching from aperture opening to aperture closure, the inter-trial variability of the end of aperture opening does not affect the high accuracy of TAC regulation in the subsequent aperture-closure phase.

How well does wind speed predict air-sea gas transfer in the sea ice zone? A synthesis of radon deficit profiles in the upper water column of the Arctic Ocean

NASA Astrophysics Data System (ADS)

Loose, B.; Kelly, R. P.; Bigdeli, A.; Williams, W.; Krishfield, R.; Rutgers van der Loeff, M.; Moran, S. B.

2017-05-01

We present 34 profiles of radon-deficit from the ice-ocean boundary layer of the Beaufort Sea. Including these 34, there are presently 58 published radon-deficit estimates of air-sea gas transfer velocity (k) in the Arctic Ocean; 52 of these estimates were derived from water covered by 10% sea ice or more. The average value of k collected since 2011 is 4.0 ± 1.2 m d-1. This exceeds the quadratic wind speed prediction of weighted kws = 2.85 m d-1 with mean-weighted wind speed of 6.4 m s-1. We show how ice cover changes the mixed-layer radon budget, and yields an "effective gas transfer velocity." We use these 58 estimates to statistically evaluate the suitability of a wind speed parameterization for k, when the ocean surface is ice covered. Whereas the six profiles taken from the open ocean indicate a statistically good fit to wind speed parameterizations, the same parameterizations could not reproduce k from the sea ice zone. We conclude that techniques for estimating k in the open ocean cannot be similarly applied to determine k in the presence of sea ice. The magnitude of k through gaps in the ice may reach high values as ice cover increases, possibly as a result of focused turbulence dissipation at openings in the free surface. These 58 profiles are presently the most complete set of estimates of k across seasons and variable ice cover; as dissolved tracer budgets they reflect air-sea gas exchange with no impact from air-ice gas exchange.

High speed hydraulically-actuated operating system for an electric circuit breaker

DOEpatents

Iman, I.

1983-06-07

This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a breaker-opening piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A dashpotting mechanism operating separately from the hydraulic actuating system is provided, thereby reducing flow restriction interference with breaker opening. 3 figs.

High speed hydraulically-actuated operating system for an electric circuit breaker

DOEpatents

Iman, Imdad

1983-06-07

This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a breaker-opening piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A dashpotting mechanism operating separately from the hydraulic actuating system is provided, thereby reducing flow restriction interference with breaker opening.

Development of a novel parallel-spool pilot operated high-pressure solenoid valve with high flow rate and high speed

NASA Astrophysics Data System (ADS)

Dong, Dai; Li, Xiaoning

2015-03-01

High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system. However, traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously. A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system. A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design. Mathematical models of the opening process and flow rate of the valve are established. Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response. Corresponding formulas to solve 4 parts of the response time are derived. Key factors that influence the opening response time are analyzed. According to the mathematical model of the valve, a simulation of the opening process is carried out by MATLAB. Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve. Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool. The experimental results are in agreement with the simulated results, therefore the validity of the theoretical analysis is verified. Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa. The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s. According to the result of the load driving test, the valve can meet the demands of the driving system. The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.

Changes in hippocampal theta rhythm and their correlations with speed during different phases of voluntary wheel running in rats.

PubMed

Li, J-Y; Kuo, T B J; Hsieh, I-T; Yang, C C H

2012-06-28

Hippocampal theta rhythm (4-12 Hz) can be observed during locomotor behavior, but findings on the relationship between locomotion speed and theta frequency are inconsistent if not contradictory. The inconsistency may be because of the difficulties that previous analyses and protocols have had excluding the effects of behavior training. We recorded the first or second voluntary wheel running each day, and assumed that theta frequency and activity are correlated with speed in different running phases. By simultaneously recording electroencephalography, physical activity, and wheel running speed, this experiment explored the theta oscillations during spontaneous running of the 12-h dark period. The recording was completely wireless and allowed the animal to run freely while being recorded in the wheel. Theta frequency and theta power of middle frequency were elevated before running and theta frequency, theta power of middle frequency, physical activity, and running speed maintained persistently high levels during running. The slopes of the theta frequency and theta activity (4-9.5 Hz) during the initial running were different compared to the same values during subsequent running. During the initial running, the running speed was positively correlated with theta frequency and with theta power of middle frequency. Over the 12-h dark period, the running speed did not positively correlate with theta frequency but was significantly correlated with theta power of middle frequency. Thus, theta frequency was associated with running speed only at the initiation of running. Furthermore, theta power of middle frequency was associated with speed and with physical activity during running when chronological order was not taken into consideration. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Spatio-Temporal Evolution of Sound Speed Channels on the Chukchi Shelf

NASA Astrophysics Data System (ADS)

Eickmeier, J.; Badiey, M.; Wan, L.

2017-12-01

The physics of an acoustic waveguide are influenced by various boundary conditions as well as spatial and temporal fluctuations in temperature and salinity profiles the water column. The shallow water Canadian Basin Acoustic Propagation Experiment (CANAPE) experiment was designed to study the effect of oceanographic variability on the acoustic field. A pilot study was conducted in the summer of 2015, full deployment of acoustic and environmental moorings took place in 2016, and recovery will occur in late 2017. An example of strong oceanographic variability in the SW region is depicted in Figure 1. Over the course of 7 days, warm Bering Sea water arrived on the Chukchi Shelf and sank in the water column to between 25 m and 125 m depth. This warm water spread to a range of 10 km and a potential eddy of warm water formed causing an increase in sound speed between 15 km and 20 km range in Fig. 1(b). Due to the increased sound speed, a strong sound channel evolved between 100 m and 200 m for acoustic waves arriving from off the shelf, deep water sources. In Fig. 1(a), the initial formation of the acoustic channel is only evident in 50 m to 100 m of water out to a range of 5 km. Recorded environmental data will be used to study fluctuations in sound speed channel formation on the Chukchi Shelf. Data collected in 2015 and 2016 have shown sound duct evolution over 7 days and over a one-month period. Analysis is projected to show sound channel formation over a new range of spatio-temporal scales. This analysis will show a cycle of sound channels opening and closing on the shelf, where this cycle strongly influences the propagation path, range and attenuation of acoustic waves.

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.

Advanced superposition methods for high speed turbopump vibration analysis

NASA Technical Reports Server (NTRS)

Nielson, C. E.; Campany, A. D.

1981-01-01

The small, high pressure Mark 48 liquid hydrogen turbopump was analyzed and dynamically tested to determine the cause of high speed vibration at an operating speed of 92,400 rpm. This approaches the design point operating speed of 95,000 rpm. The initial dynamic analysis in the design stage and subsequent further analysis of the rotor only dynamics failed to predict the vibration characteristics found during testing. An advanced procedure for dynamics analysis was used in this investigation. The procedure involves developing accurate dynamic models of the rotor assembly and casing assembly by finite element analysis. The dynamically instrumented assemblies are independently rap tested to verify the analytical models. The verified models are then combined by modal superposition techniques to develop a completed turbopump model where dynamic characteristics are determined. The results of the dynamic testing and analysis obtained are presented and methods of moving the high speed vibration characteristics to speeds above the operating range are recommended. Recommendations for use of these advanced dynamic analysis procedures during initial design phases are given.

A portable high-speed camera system for vocal fold examinations.

PubMed

Hertegård, Stellan; Larsson, Hans

2014-11-01

In this article, we present a new portable low-cost system for high-speed examinations of the vocal folds. Analysis of glottal vibratory parameters from the high-speed recordings is compared with videostroboscopic recordings. The high-speed system is built around a Fastec 1 monochrome camera, which is used with newly developed software, High-Speed Studio (HSS). The HSS has options for video/image recording, contains a database, and has a set of analysis options. The Fastec/HSS system has been used clinically since 2011 in more than 2000 patient examinations and recordings. The Fastec 1 camera has sufficient time resolution (≥4000 frames/s) and light sensitivity (ISO 3200) to produce images for detailed analyses of parameters pertinent to vocal fold function. The camera can be used with both rigid and flexible endoscopes. The HSS software includes options for analyses of glottal vibrations, such as kymogram, phase asymmetry, glottal area variation, open and closed phase, and angle of vocal fold abduction. It can also be used for separate analysis of the left and vocal fold movements, including maximum speed during opening and closing, a parameter possibly related to vocal fold elasticity. A blinded analysis of 32 patients with various voice disorders examined with both the Fastec/HSS system and videostroboscopy showed that the high-speed recordings were significantly better for the analysis of glottal parameters (eg, mucosal wave and vibration asymmetry). The monochrome high-speed system can be used in daily clinical work within normal clinical time limits for patient examinations. A detailed analysis can be made of voice disorders and laryngeal pathology at a relatively low cost. Copyright © 2014 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Open Data in Biomedical Science: Policy Drivers and Recent ...

EPA Pesticide Factsheets

EPA's progress in implementing the open data initiatives first outlined in the 2009 Presidential memorandum on open government and more specifically regarding publications and data from publications in the 2013 Holdren memorandum. The presentation outlines the major points in both memorandums regarding open data, presents several (but not exhaustive) EPA initiatives on open data, some of which occurred will before both policy memorandums. The presentation concludes by outlining the initiatives to ensure public access to all EPA publications through PubMed Central and all publication-associated data through the Environmental Data Gateway and Data.gov. The purpose of this presentation is to present EPA's progress in implementing the open data initiatives first outlined in the 2009 Presidential memorandum on open government and more specifically regarding publications and data from publications in the 2013 Holdren memorandum.

High speed door assembly

DOEpatents

Shapiro, Carolyn

1993-01-01

A high speed door assembly, comprising an actuator cylinder and piston rods, a pressure supply cylinder and fittings, an electrically detonated explosive bolt, a honeycomb structured door, a honeycomb structured decelerator, and a structural steel frame encasing the assembly to close over a 3 foot diameter opening within 50 milliseconds of actuation, to contain hazardous materials and vapors within a test fixture.

High-speed trains subject to abrupt braking

NASA Astrophysics Data System (ADS)

Tran, Minh Thi; Ang, Kok Keng; Luong, Van Hai; Dai, Jian

2016-12-01

The dynamic response of high-speed train subject to braking is investigated using the moving element method. Possible sliding of wheels over the rails is accounted for. The train is modelled as a 15-DOF system comprising of a car body, two bogies and four wheels interconnected by spring-damping units. The rail is modelled as a Euler-Bernoulli beam resting on a two-parameter elastic damped foundation. The interaction between the moving train and track-foundation is accounted for through the normal and tangential wheel-rail contact forces. The effects of braking torque, wheel-rail contact condition, initial train speed and severity of railhead roughness on the dynamic response of the high-speed train are investigated. For a given initial train speed and track irregularity, the study revealed that there is an optimal braking torque that would result in the smallest braking distance with no occurrence of wheel sliding, representing a good compromise between train instability and safety.

On discharge from poppet valves: effects of pressure and system dynamics

NASA Astrophysics Data System (ADS)

Winroth, P. M.; Ford, C. L.; Alfredsson, P. H.

2018-02-01

Simplified flow models are commonly used to design and optimize internal combustion engine systems. The exhaust valves and ports are modelled as straight pipe flows with a corresponding discharge coefficient. The discharge coefficient is usually determined from steady-flow experiments at low pressure ratios and at fixed valve lifts. The inherent assumptions are that the flow through the valve is insensitive to the pressure ratio and may be considered as quasi-steady. The present study challenges these two assumptions through experiments at varying pressure ratios and by comparing measurements of the discharge coefficient obtained under steady and dynamic conditions. Steady flow experiments were performed in a flow bench, whereas the dynamic measurements were performed on a pressurized, 2 l, fixed volume cylinder with one or two moving valves. In the latter experiments an initial pressure (in the range 300-500 kPa) was established whereafter the valve(s) was opened with a lift profile corresponding to different equivalent engine speeds (in the range 800-1350 rpm). The experiments were only concerned with the blowdown phase, i.e. the initial part of the exhaustion process since no piston was simulated. The results show that the process is neither pressure-ratio independent nor quasi-steady. A measure of the "steadiness" has been defined, relating the relative change in the open flow area of the valve to the relative change of flow conditions in the cylinder, a measure that indicates if the process can be regarded as quasi-steady or not.

Parents - Reboot.FCC.gov

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78 FR 6202 - Airworthiness Directives; the Boeing Company

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-30

... Descent (If INITIATE Required). Passenger Oxygen Switch.... ON Thrust Levers CLOSE Speed Brakes FLIGHT... Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind... regard. Request To Correct AFM Reference to Target Speed Delta Airlines (DAL) asked that the target speed...

Using laser-driven flyer plates to study the shock initiation of nanoenergetic materials

NASA Astrophysics Data System (ADS)

Shaw, William; Dlott, Dana

2013-06-01

A tabletop system has been developed to launch aluminum laser-driven flyer plates at speeds up to 4 km/s. The flyer plates are used to initiate a variety of nanoenergetic materials including aluminum/iron oxide particles produced by arrested ball milling, and multi-layer nano-thermites produced by sputtering. The initiation process is probed by a variety of high-speed diagnostics including time-resolved emission spectroscopy. Impact velocity initiation thresholds for different thickness flyer plates, producing different duration shocks, were determined. The durations of the emission bursts and the effects of nanostructure and microstructure on these bursts were used to investigate the fundamental mechanisms of impact initiation.

Moving the Barricades to Physical Activity: A Qualitative Analysis of Open Streets Initiatives Across the United States.

PubMed

Eyler, Amy A; Hipp, J Aaron; Lokuta, Julie

2015-01-01

Ciclovía, or Open Streets initiatives, are events where streets are opened for physical activity and closed to motorized traffic. Although the initiatives are gaining popularity in the United States, little is known about planning and implementing them. The goals of this paper are to explore the development and implementation of Open Streets initiatives and make recommendations for increasing the capacity of organizers to enhance initiative success. Phenomenology with qualitative analysis of structured interviews was used. Study setting was urban and suburban communities in the United States. Study participants were organizers of Open Streets initiatives in U.S. cities. Using a list of 47 events held in 2011, 27 lead organizers were interviewed by telephone about planning, implementation, and lessons learned. The interviews were digitally recorded and transcribed. A phenomenologic approach was used, an initial coding tool was developed after reviewing a sample of transcripts, and constant comparative coding methodology was applied. Themes and subthemes were generated from codes. The most common reasons for initiation were to highlight or improve health and transportation. Most initiatives aimed to reach the general population, but some targeted families, children, or specific neighborhoods. Getting people to understand the concept of Open Streets was an important challenge. Other challenges included lack of funding and personnel, and complex logistics. These initiatives democratize public space for citizens while promoting physical activity, social connectedness, and other broad agendas. There are opportunities for the research community to contribute to the expanse and sustainability of Open Streets, particularly in evaluation and dissemination.

Characteristics of a wind-actuated aerodynamic braking device for high-speed trains

NASA Astrophysics Data System (ADS)

Takami, H.; Maekawa, H.

2017-04-01

To shorten the stopping distance of the high speed trains in case of emergency, we developed a small-sized aerodynamic braking unit without use of the friction between a rail and a wheel. The developed device could actuate a pair of two drag panels with a travelling wind. However, after the drag panel fully opened, vibrational movements of the drag panel characterized by its slight flutter were repeated. In this study, to stabilize the opened panel, matters pertaining to the angle of attack with respect to the drag panel and pertaining to the arrangement of the two panels were examined by a wind tunnel experiment using a scale model. As a result, to stabilize the opened panel and to keep the good performance of the braking device, it is found out that an angle of attack of 75 to 80 degrees is suitable provided that the interval of the two panels is narrow enough.

The Detection And Analysis Of Blasting Problems Encountered In A Colliery Using High Speed Photography

NASA Astrophysics Data System (ADS)

Rorke, A. J.; Kohler, E. W.

1987-09-01

Premature initiation of ANFO (an explosive mixture of Ammonium Nitrate and Fuel Oil) at a large colliery, near Witbank, was first detected from routine high speed films taken of large mid-burden, and overburden blasts. The analysis of these films shows that the rapid migration of very hot gasses through cracks ahead of the blast may have caused the explosive to initiate prematurely. The problem was not seen in the less competent overburden rocks. A less sensitive explosive has been successfully tried. The assessment of these blasts using high speed photography is discussed.

Near-surface compressional and shear wave speeds constrained by body-wave polarization analysis

NASA Astrophysics Data System (ADS)

Park, Sunyoung; Ishii, Miaki

2018-06-01

A new technique to constrain near-surface seismic structure that relates body-wave polarization direction to the wave speed immediately beneath a seismic station is presented. The P-wave polarization direction is only sensitive to shear wave speed but not to compressional wave speed, while the S-wave polarization direction is sensitive to both wave speeds. The technique is applied to data from the High-Sensitivity Seismograph Network in Japan, and the results show that the wave speed estimates obtained from polarization analysis are compatible with those from borehole measurements. The lateral variations in wave speeds correlate with geological and physical features such as topography and volcanoes. The technique requires minimal computation resources, and can be used on any number of three-component teleseismic recordings, opening opportunities for non-invasive and inexpensive study of the shallowest (˜100 m) crustal structures.

Large fully retractable telescope enclosures still closable in strong wind

NASA Astrophysics Data System (ADS)

Bettonvil, Felix C. M.; Hammerschlag, Robert H.; Jägers, Aswin P. L.; Sliepen, Guus

2008-07-01

Two prototypes of fully retractable enclosures with diameters of 7 and 9 m have been built for the high-resolution solar telescopes DOT (Dutch Open Telescope) and GREGOR, both located at the Canary Islands. These enclosures protect the instruments for bad weather and are fully open when the telescopes are in operation. The telescopes and enclosures also operate in hard wind. The prototypes are based on tensioned membrane between movable but stiff bows, which fold together to a ring when opened. The height of the ring is small. The prototypes already survived several storms, with often snow and ice, without any damage, including hurricane Delta with wind speeds up to 68 m/s. The enclosures can still be closed and opened with wind speeds of 20 m/s without any problems or restrictions. The DOT successfully demonstrated the open, wind-flushing concept for astronomical telescopes. It is now widely recognized that also large future telescopes benefit from wind-flushing and retractable enclosures. These telescopes require enclosures with diameters of 30 m until roughly 100 m, the largest sizes for the ELTs (Extreme Large Telescopes), which will be built in the near future. We discuss developments and required technology for the realization of these large sizes.

Cell voltage versus electrode potential range in aqueous supercapacitors

PubMed Central

Dai, Zengxin; Peng, Chuang; Chae, Jung Hoon; Ng, Kok Chiang; Chen, George Z.

2015-01-01

Supercapacitors with aqueous electrolytes and nanostructured composite electrodes are attractive because of their high charging-discharging speed, long cycle life, low environmental impact and wide commercial affordability. However, the energy capacity of aqueous supercapacitors is limited by the electrochemical window of water. In this paper, a recently reported engineering strategy is further developed and demonstrated to correlate the maximum charging voltage of a supercapacitor with the capacitive potential ranges and the capacitance ratio of the two electrodes. Beyond the maximum charging voltage, a supercapacitor may still operate, but at the expense of a reduced cycle life. In addition, it is shown that the supercapacitor performance is strongly affected by the initial and zero charge potentials of the electrodes. Further, the differences are highlighted and elaborated between freshly prepared, aged under open circuit conditions, and cycled electrodes of composites of conducting polymers and carbon nanotubes. The first voltammetric charging-discharging cycle has an electrode conditioning effect to change the electrodes from their initial potentials to the potential of zero voltage, and reduce the irreversibility. PMID:25897670

A study on the gas-solid particle flows in a needle-free drug delivery device

NASA Astrophysics Data System (ADS)

Rasel, Md. Alim Iftekhar; Taher, Md. Abu; Kim, H. D.

2013-08-01

Different systems have been used over the years to deliver drug particles to the human skin for pharmaceutical effect. Research has been done to improve the performance and flexibility of these systems. In recent years a unique system called the transdermal drug delivery has been developed. Transdermal drug delivery opened a new door in the field of drug delivery as it is more flexible and offers better performance than the conventional systems. The principle of this system is to accelerate drug particles with a high speed gas flow. Among different transdermal drug delivery systems we will concentrate on the contour shock tube system in this paper. A contoured shock tube is consists of a rupture chamber, a shock tube and a supersonic nozzle section. The drug particles are retained between a set of bursting diaphragm. When the diaphragm is ruptured at a certain pressure, a high speed unsteady flow is initiated through the shock tube which accelerates the particles. Computational fluid dynamics is used to simulate and analyze the flow field. The DPM (discrete phase method) is used to model the particle flow. As an unsteady flow is initiated though the shock tube the drag correlation proposed by Igra et al is used other than the standard drag correlation. The particle velocities at different sections including the nozzle exit are investigated under different operating conditions. Static pressure histories in different sections in the shock tube are investigated to analyze the flow field. The important aspects of the gas and particle dynamics in the shock tube are discussed and analyzed in details.

The association between speed of transition from initiation to subsequent use of cannabis and later problematic cannabis use, abuse and dependence.

PubMed

Hines, Lindsey A; Morley, Katherine I; Strang, John; Agrawal, Arpana; Nelson, Elliot C; Statham, Dixie; Martin, Nicholas G; Lynskey, Michael T

2015-08-01

To test whether speed of transition from initiation use to subsequent use of cannabis is associated with likelihood of later cannabis dependence and other outcomes, and whether transition speed is attributable to genetic or environmental factors. Cross-sectional interview study. Australia. A total of 2239 twins and siblings who reported using cannabis at least twice [mean age at time of survey = 32.0, 95% confidence interval (CI) = 31.9 - 32.1, range = 22-45]. Time between initiation and subsequent cannabis use (within 1 week; within 3 months; between 3 and 12 months; more than 1 year later), later use of cannabis and symptoms of DSM-IV cannabis abuse/dependence. Multinomial regression analyses (comparison group: more than 1 year later) adjusted the association between speed of transition and the outcomes of cannabis daily use, abuse/dependence and treatment-seeking after controlling for socio-demographic, childhood, mental health, peer and licit drug factors. Twin modelling estimated the proportion of variance in transition speed attributable to genetic (A), common environment (C) and unique environmental (E) factors. Subsequent use of cannabis within 1 week of initiation was associated with daily use [odds ratio (OR) = 2.64, 95% CI = 1.75-3.99], abuse and/or dependence (OR = 3.25, 95% CI = 2.31-4.56) and treatment-seeking for cannabis problems (OR = 1.89, 95% CI = 1.03-3.46). Subsequent use within 3 months was associated with abuse and/or dependence (OR = 1.61, 95% CI = 1.18-2.19). The majority of the variation of the speed of transition was accounted for by unique environment factors (0.75). Rapid transition from initiation to subsequent use of cannabis is associated with increased likelihood of subsequent daily cannabis use and abuse/dependence. © 2015 Society for the Study of Addiction.

42 CFR 457.370 - Alignment with Exchange initial open enrollment period.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 4 2013-10-01 2013-10-01 false Alignment with Exchange initial open enrollment period. 457.370 Section 457.370 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF... Alignment with Exchange initial open enrollment period. The terms of § 435.1205 apply equally to the State...

The development speed paradox: can increasing development speed reduce R&D productivity?

PubMed

Lendrem, Dennis W; Lendrem, B Clare

2014-03-01

In the 1990s the pharmaceutical industry sought to increase R&D productivity by shifting development tasks into parallel to reduce development cycle times and increase development speed. This paper presents a simple model demonstrating that, when attrition rates are high as in pharmaceutical development, such development speed initiatives can increase the expected time for the first successful molecule to complete development. Increasing the development speed of successful molecules could actually reduce R&D productivity - the development speed paradox. Copyright © 2013 Elsevier Ltd. All rights reserved.

State-of-the-Art in Open Courseware Initiatives Worldwide

ERIC Educational Resources Information Center

Vladoiu, Monica

2011-01-01

We survey here the state-of-the-art in open courseware initiatives worldwide. First, the MIT OpenCourseWare project is overviewed, as it has been the real starting point of the OCW movement. Usually, open courseware refers to a free and open digital publication of high quality university level educational materials that are organized as courses,…

REAL-TIME MODEL-BASED ELECTRICAL POWERED WHEELCHAIR CONTROL

PubMed Central

Wang, Hongwu; Salatin, Benjamin; Grindle, Garrett G.; Ding, Dan; Cooper, Rory A.

2009-01-01

The purpose of this study was to evaluate the effects of three different control methods on driving speed variation and wheel-slip of an electric-powered wheelchair (EPW). A kinematic model as well as 3-D dynamic model was developed to control the velocity and traction of the wheelchair. A smart wheelchair platform was designed and built with a computerized controller and encoders to record wheel speeds and to detect the slip. A model based, a proportional-integral-derivative (PID) and an open-loop controller were applied with the EPW driving on four different surfaces at three specified speeds. The speed errors, variation, rise time, settling time and slip coefficient were calculated and compared for a speed step-response input. Experimental results showed that model based control performed best on all surfaces across the speeds. PMID:19733494

Large grain instruction and phonological awareness skill influence rime sensitivity, processing speed, and early decoding skill in adult L2 learners

PubMed Central

Brennan, Christine; Booth, James R.

2016-01-01

Linguistic knowledge, cognitive ability, and instruction influence how adults acquire a second orthography yet it remains unclear how different forms of instruction influence grain size sensitivity and subsequent decoding skill and speed. Thirty-seven monolingual, literate English-speaking adults were trained on a novel artificial orthography given initial instruction that directed attention to either large or small grain size units (i.e., words or letters). We examined how initial instruction influenced processing speed (i.e., reaction time (RT)) and sensitivity to different orthographic grain sizes (i.e., rimes and letters). Directing attention to large grain size units during initial instruction resulted in higher accuracy for rimes, whereas directing attention to smaller grain size units resulted in slower RTs across all measures. Additionally, phonological awareness skill modulated early learning effects, compensating for the limitations of the initial instruction provided. Collectively, these findings suggest that when adults are learning to read a second orthography, consideration should be given to how initial instruction directs attention to different grain sizes and inherent phonological awareness ability. PMID:27829705

Analyzing huge pathology images with open source software.

PubMed

Deroulers, Christophe; Ameisen, David; Badoual, Mathilde; Gerin, Chloé; Granier, Alexandre; Lartaud, Marc

2013-06-06

Digital pathology images are increasingly used both for diagnosis and research, because slide scanners are nowadays broadly available and because the quantitative study of these images yields new insights in systems biology. However, such virtual slides build up a technical challenge since the images occupy often several gigabytes and cannot be fully opened in a computer's memory. Moreover, there is no standard format. Therefore, most common open source tools such as ImageJ fail at treating them, and the others require expensive hardware while still being prohibitively slow. We have developed several cross-platform open source software tools to overcome these limitations. The NDPITools provide a way to transform microscopy images initially in the loosely supported NDPI format into one or several standard TIFF files, and to create mosaics (division of huge images into small ones, with or without overlap) in various TIFF and JPEG formats. They can be driven through ImageJ plugins. The LargeTIFFTools achieve similar functionality for huge TIFF images which do not fit into RAM. We test the performance of these tools on several digital slides and compare them, when applicable, to standard software. A statistical study of the cells in a tissue sample from an oligodendroglioma was performed on an average laptop computer to demonstrate the efficiency of the tools. Our open source software enables dealing with huge images with standard software on average computers. They are cross-platform, independent of proprietary libraries and very modular, allowing them to be used in other open source projects. They have excellent performance in terms of execution speed and RAM requirements. They open promising perspectives both to the clinician who wants to study a single slide and to the research team or data centre who do image analysis of many slides on a computer cluster. The virtual slide(s) for this article can be found here:http://www.diagnosticpathology.diagnomx.eu/vs/5955513929846272.

Analyzing huge pathology images with open source software

PubMed Central

2013-01-01

Background Digital pathology images are increasingly used both for diagnosis and research, because slide scanners are nowadays broadly available and because the quantitative study of these images yields new insights in systems biology. However, such virtual slides build up a technical challenge since the images occupy often several gigabytes and cannot be fully opened in a computer’s memory. Moreover, there is no standard format. Therefore, most common open source tools such as ImageJ fail at treating them, and the others require expensive hardware while still being prohibitively slow. Results We have developed several cross-platform open source software tools to overcome these limitations. The NDPITools provide a way to transform microscopy images initially in the loosely supported NDPI format into one or several standard TIFF files, and to create mosaics (division of huge images into small ones, with or without overlap) in various TIFF and JPEG formats. They can be driven through ImageJ plugins. The LargeTIFFTools achieve similar functionality for huge TIFF images which do not fit into RAM. We test the performance of these tools on several digital slides and compare them, when applicable, to standard software. A statistical study of the cells in a tissue sample from an oligodendroglioma was performed on an average laptop computer to demonstrate the efficiency of the tools. Conclusions Our open source software enables dealing with huge images with standard software on average computers. They are cross-platform, independent of proprietary libraries and very modular, allowing them to be used in other open source projects. They have excellent performance in terms of execution speed and RAM requirements. They open promising perspectives both to the clinician who wants to study a single slide and to the research team or data centre who do image analysis of many slides on a computer cluster. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5955513929846272 PMID:23829479

Revisiting Molecular Dynamics on a CPU/GPU system: Water Kernel and SHAKE Parallelization.

PubMed

Ruymgaart, A Peter; Elber, Ron

2012-11-13

We report Graphics Processing Unit (GPU) and Open-MP parallel implementations of water-specific force calculations and of bond constraints for use in Molecular Dynamics simulations. We focus on a typical laboratory computing-environment in which a CPU with a few cores is attached to a GPU. We discuss in detail the design of the code and we illustrate performance comparable to highly optimized codes such as GROMACS. Beside speed our code shows excellent energy conservation. Utilization of water-specific lists allows the efficient calculations of non-bonded interactions that include water molecules and results in a speed-up factor of more than 40 on the GPU compared to code optimized on a single CPU core for systems larger than 20,000 atoms. This is up four-fold from a factor of 10 reported in our initial GPU implementation that did not include a water-specific code. Another optimization is the implementation of constrained dynamics entirely on the GPU. The routine, which enforces constraints of all bonds, runs in parallel on multiple Open-MP cores or entirely on the GPU. It is based on Conjugate Gradient solution of the Lagrange multipliers (CG SHAKE). The GPU implementation is partially in double precision and requires no communication with the CPU during the execution of the SHAKE algorithm. The (parallel) implementation of SHAKE allows an increase of the time step to 2.0fs while maintaining excellent energy conservation. Interestingly, CG SHAKE is faster than the usual bond relaxation algorithm even on a single core if high accuracy is expected. The significant speedup of the optimized components transfers the computational bottleneck of the MD calculation to the reciprocal part of Particle Mesh Ewald (PME).

Geospace simulations using modern accelerator processor technology

NASA Astrophysics Data System (ADS)

Germaschewski, K.; Raeder, J.; Larson, D. J.

2009-12-01

OpenGGCM (Open Geospace General Circulation Model) is a well-established numerical code simulating the Earth's space environment. The most computing intensive part is the MHD (magnetohydrodynamics) solver that models the plasma surrounding Earth and its interaction with Earth's magnetic field and the solar wind flowing in from the sun. Like other global magnetosphere codes, OpenGGCM's realism is currently limited by computational constraints on grid resolution. OpenGGCM has been ported to make use of the added computational powerof modern accelerator based processor architectures, in particular the Cell processor. The Cell architecture is a novel inhomogeneous multicore architecture capable of achieving up to 230 GFLops on a single chip. The University of New Hampshire recently acquired a PowerXCell 8i based computing cluster, and here we will report initial performance results of OpenGGCM. Realizing the high theoretical performance of the Cell processor is a programming challenge, though. We implemented the MHD solver using a multi-level parallelization approach: On the coarsest level, the problem is distributed to processors based upon the usual domain decomposition approach. Then, on each processor, the problem is divided into 3D columns, each of which is handled by the memory limited SPEs (synergistic processing elements) slice by slice. Finally, SIMD instructions are used to fully exploit the SIMD FPUs in each SPE. Memory management needs to be handled explicitly by the code, using DMA to move data from main memory to the per-SPE local store and vice versa. We use a modern technique, automatic code generation, which shields the application programmer from having to deal with all of the implementation details just described, keeping the code much more easily maintainable. Our preliminary results indicate excellent performance, a speed-up of a factor of 30 compared to the unoptimized version.

Computer analysis of multicircuit shells of revolution by the field method

NASA Technical Reports Server (NTRS)

Cohen, G. A.

1975-01-01

The field method, presented previously for the solution of even-order linear boundary value problems defined on one-dimensional open branch domains, is extended to boundary value problems defined on one-dimensional domains containing circuits. This method converts the boundary value problem into two successive numerically stable initial value problems, which may be solved by standard forward integration techniques. In addition, a new method for the treatment of singular boundary conditions is presented. This method, which amounts to a partial interchange of the roles of force and displacement variables, is problem independent with respect to both accuracy and speed of execution. This method was implemented in a computer program to calculate the static response of ring stiffened orthotropic multicircuit shells of revolution to asymmetric loads. Solutions are presented for sample problems which illustrate the accuracy and efficiency of the method.

Direct AFM observation of an opening event of a DNA cuboid constructed via a prism structure.

PubMed

Endo, Masayuki; Hidaka, Kumi; Sugiyama, Hiroshi

2011-04-07

A cuboid structure was constructed using a DNA origami design based on a square prism structure. The structure was characterized by atomic force microscopy (AFM) and dynamic light scattering. The real-time opening event of the cuboid was directly observed by high-speed AFM.

Design and performance evaluation of an OpenFlow-based control plane for software-defined elastic optical networks with direct-detection optical OFDM (DDO-OFDM) transmission.

PubMed

Liu, Lei; Peng, Wei-Ren; Casellas, Ramon; Tsuritani, Takehiro; Morita, Itsuro; Martínez, Ricardo; Muñoz, Raül; Yoo, S J B

2014-01-13

Optical Orthogonal Frequency Division Multiplexing (O-OFDM), which transmits high speed optical signals using multiple spectrally overlapped lower-speed subcarriers, is a promising candidate for supporting future elastic optical networks. In contrast to previous works which focus on Coherent Optical OFDM (CO-OFDM), in this paper, we consider the direct-detection optical OFDM (DDO-OFDM) as the transport technique, which leads to simpler hardware and software realizations, potentially offering a low-cost solution for elastic optical networks, especially in metro networks, and short or medium distance core networks. Based on this network scenario, we design and deploy a software-defined networking (SDN) control plane enabled by extending OpenFlow, detailing the network architecture, the routing and spectrum assignment algorithm, OpenFlow protocol extensions and the experimental validation. To the best of our knowledge, it is the first time that an OpenFlow-based control plane is reported and its performance is quantitatively measured in an elastic optical network with DDO-OFDM transmission.

Exploding wires initiation of nitromethane sensitized by diethylenetriamine

NASA Astrophysics Data System (ADS)

Ushnurtsev, A. E.; Shilkin, N. S.; Utkin, A. V.; Mintsev, V. B.

2018-01-01

Experiments on initiation of nitromethane sensitized by diethylenetriamine in weight proportion 98/2 by exploding wires were conducted. Several conditions of initiation of low speed detonation were determined.

Idling speed control system of an internal combustion engine

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

Miyazaki, M.; Ishii, M.; Kako, H.

1986-09-16

This patent describes an idling speed control system of an internal combustion engine comprising: a valve device which controls the amount of intake air for the engine; an actuator which includes an electric motor for variably controlling the opening of the value device; rotation speed detector means for detecting the rotation speed of the engine; idling condition detector means for detecting the idling condition of the engine; feedback control means responsive to the detected output of the idling condition detector means for generating feedback control pulses to intermittently drive the electric motor so that the detected rotation speed of themore » engine under the idling condition may converge into a target idling rotation speed; and control means responsive to the output of detector means that detects an abnormally low rotation speed of the engine detected by the rotation speed detector means for generating control pulses that do not overlap the feedback control pulses to drive the electric motor in a predetermined direction.« less

High speed door assembly

DOEpatents

Shapiro, C.

1993-04-27

A high speed door assembly is described, comprising an actuator cylinder and piston rods, a pressure supply cylinder and fittings, an electrically detonated explosive bolt, a honeycomb structured door, a honeycomb structured decelerator, and a structural steel frame encasing the assembly to close over a 3 foot diameter opening within 50 milliseconds of actuation, to contain hazardous materials and vapors within a test fixture.

Outflow structure of the quiet sun corona probed by spacecraft radio scintillations in strong scattering

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

Imamura, Takeshi; Ando, Hiroki; Toda, Tomoaki

Radio scintillation observations have been unable to probe flow speeds in the low corona where the scattering of radio waves is exceedingly strong. Here we estimate outflow speeds continuously from the vicinity of the Sun to the outer corona (heliocentric distances of 1.5-20.5 solar radii) by applying the strong scattering theory to radio scintillations for the first time, using the Akatsuki spacecraft as the radio source. Small, nonzero outflow speeds were observed over a wide latitudinal range in the quiet-Sun low corona, suggesting that the supply of plasma from closed loops to the solar wind occurs over an extended area.more » The existence of power-law density fluctuations down to the scale of 100 m was suggested, which is indicative of well-developed turbulence which can play a key role in heating the corona. At higher altitudes, a rapid acceleration typical of radial open fields is observed, and the temperatures derived from the speed profile show a distinct maximum in the outer corona. This study opened up a possibility of observing detailed flow structures near the Sun from a vast amount of existing interplanetary scintillation data.« less

High-Speed Additive Manufacturing Through High-Aspect-Ratio Nozzles

NASA Astrophysics Data System (ADS)

Shaw, Leon; Islam, Mashfiqul; Li, Jie; Li, Ling; Ayub, S. M. Imran

2018-03-01

The feasibility of layer-by-layer manufacturing through high-aspect-ratio (HAR) nozzles for microextrusion of paste to deposit planes has been investigated. Various conditions for paste extrusion, including nozzle moving speed, piston speed, extrusion rate, and distance between the nozzle tip and substrate, have been evaluated. By linking various microextrusion parameters together with the aid of a critical distance concept derived from microextrusion using circular nozzles and addressing the extrusion delay in response to the change of the piston speed and air pocket problems properly, we successfully microextruded single planes, multilayer objects, and larger planes made of multiple smaller planes side by side through HAR nozzles. It is further demonstrated that the X- Y dimensions of an extruded plane in the steady-state extrusion stage are determined by the nozzle travel distance and the length of the HAR nozzle opening if microextrusion is conducted with proper conditions. However, the height of the extruded plane is not only determined by the microextrusion conditions, but also affected by the drying shrinkage of the paste after microextrusion. This demonstration of the feasibility of using a HAR nozzle machine opens the door to manufacture of multimaterial, multilayer devices with high productivity in the near future.

Influences of Cutting Speed and Material Mechanical Properties on Chip Deformation and Fracture during High-Speed Cutting of Inconel 718.

PubMed

Wang, Bing; Liu, Zhanqiang; Hou, Xin; Zhao, Jinfu

2018-03-21

The paper aims to investigate the influences of material constitutive and fracture parameters in addition to cutting speed on chip formation during high-speed cutting of Inconel 718. Finite element analyses for chip formation are conducted with Johnson-Cook constitutive and fracture models. Meanwhile, experiments of high-speed orthogonal cutting are performed to verify the simulation results with cutting speeds ranging from 50 m/min to 7000 m/min. The research indicates that the chip morphology transforms from serrated to fragmented at the cutting speed of 7000 m/min due to embrittlement of the workpiece material under ultra-high cutting speeds. The parameter of shear localization sensitivity is put forward to describe the influences of material mechanical properties on serrated chip formation. The results demonstrate that the effects of initial yield stress and thermal softening coefficient on chip shear localization are much more remarkable than the other constitutive parameters. For the material fracture parameters, the effects of initial fracture strain and exponential factor of stress state on chip shear localization are more much prominent. This paper provides guidance for controlling chip formation through the adjustment of material mechanical properties and the selection of appropriate cutting parameters.

Influences of Cutting Speed and Material Mechanical Properties on Chip Deformation and Fracture during High-Speed Cutting of Inconel 718

PubMed Central

Hou, Xin; Zhao, Jinfu

2018-01-01

The paper aims to investigate the influences of material constitutive and fracture parameters in addition to cutting speed on chip formation during high-speed cutting of Inconel 718. Finite element analyses for chip formation are conducted with Johnson–Cook constitutive and fracture models. Meanwhile, experiments of high-speed orthogonal cutting are performed to verify the simulation results with cutting speeds ranging from 50 m/min to 7000 m/min. The research indicates that the chip morphology transforms from serrated to fragmented at the cutting speed of 7000 m/min due to embrittlement of the workpiece material under ultra-high cutting speeds. The parameter of shear localization sensitivity is put forward to describe the influences of material mechanical properties on serrated chip formation. The results demonstrate that the effects of initial yield stress and thermal softening coefficient on chip shear localization are much more remarkable than the other constitutive parameters. For the material fracture parameters, the effects of initial fracture strain and exponential factor of stress state on chip shear localization are more much prominent. This paper provides guidance for controlling chip formation through the adjustment of material mechanical properties and the selection of appropriate cutting parameters. PMID:29561770

Turbomolecular Pumps for Holding Gases in Open Containers

NASA Technical Reports Server (NTRS)

Keller, John W.; Lorenz, John E.

2010-01-01

Proposed special-purpose turbomolecular pumps denoted turbotraps would be designed, along with mating open containers, to prevent the escape of relatively slowly (thermal) moving gas molecules from the containers while allowing atoms moving at much greater speeds to pass through. In the original intended applications, the containers would be electron-attachment cells, and the contained gases would be vapors of alkali metal atoms moving at thermal speeds that would be of the order of a fraction of 300 meters per second. These cells would be parts of apparatuses used to measure fluxes of neutral atoms incident at kinetic energies in the approximate range of 10 eV to 10 keV (corresponding to typical speeds of the order of 40,000 m/s and higher). The incident energetic neutral atoms would pass through the cells, wherein charge-exchange reactions with the alkali metal atoms would convert the neutral atoms to negative ions, which, in turn, could then be analyzed by use of conventional charged-particle optics.

Field Calibration of XAD-Based Passive Air Sampler on the Tibetan Plateau: Wind Influence and Configuration Improvement.

PubMed

Gong, Ping; Wang, Xiaoping; Liu, Xiande; Wania, Frank

2017-05-16

The passive air sampler based on XAD-2 resin (XAD-PAS) has proven useful for collecting atmospheric persistent organic pollutants (POPs) in remote regions. Whereas laboratory studies have shown that, due to the open bottom of its housing, the passive sampling rate (PSR) of the XAD-PAS is susceptible to wind and other processes causing air turbulence, the sampler has not been calibrated in the field at sites experiencing high winds. In this study, the PSRs of the XAD-PAS were calibrated at three sites on the Tibetan Plateau, covering a wide range in temperature (T), pressure (P) and wind speed (v). At sites with low wind speeds (i.e., in a forest and an urban site), the PSRs are proportional to the ratio T 1.75 / P; at windy sites with an average wind speed above 3 m/s, the influence of v on PSRs cannot be ignored. Moreover, the open bottom of the XAD-PAS housing causes the PSRs to be influenced by wind angle and air turbulence caused by sloped terrain. Field calibration, wind speed measurements, and computational fluid dynamics (CFD) simulations indicate that a modified design incorporating an air spoiler consisting of 4 metal sheets dampens the turbulence caused by wind angle and sloped terrain and caps the PSR at ∼5 m 3 /day, irrespective of ambient wind. Therefore, the original XAD-PAS with an open bottom is suitable for deployment in urban areas and other less windy places, the modified design is preferable in mountain regions and other places where air circulation is complicated and strong.

Budgerigar flight in a varying environment: flight at distinct speeds?

PubMed

Schiffner, Ingo; Srinivasan, Mandyam V

2016-06-01

How do flying birds respond to changing environments? The behaviour of budgerigars, Melopsittacus undulatus, was filmed as they flew through a tapered tunnel. Unlike flying insects-which vary their speed progressively and continuously by holding constant the optic flow induced by the walls-the birds showed a tendency to fly at only two distinct, fixed speeds. They switched between a high speed in the wider section of the tunnel, and a low speed in the narrower section. The transition between the two speeds was abrupt, and anticipatory. The high speed was close to the energy-efficient, outdoor cruising speed for these birds, while the low speed was approximately half this value. This is the first observation of the existence of two distinct, preferred flight speeds in birds. A dual-speed flight strategy may be beneficial for birds that fly in varying environments, with the high speed set at an energy-efficient value for flight through open spaces, and the low speed suited to safe manoeuvring in a cluttered environment. The constancy of flight speed within each regime enables the distances of obstacles and landmarks to be directly calibrated in terms of optic flow, thus facilitating simple and efficient guidance of flight through changing environments. © 2016 The Author(s).

Difference in the wind speeds required for initiation versus continuation of sand transport on mars: implications for dunes and dust storms.

PubMed

Kok, Jasper F

2010-02-19

Much of the surface of Mars is covered by dunes, ripples, and other features formed by the blowing of sand by wind, known as saltation. In addition, saltation loads the atmosphere with dust aerosols, which dominate the Martian climate. We show here that saltation can be maintained on Mars by wind speeds an order of magnitude less than required to initiate it. We further show that this hysteresis effect causes saltation to occur for much lower wind speeds than previously thought. These findings have important implications for the formation of dust storms, sand dunes, and ripples on Mars.

PyXRF: Python-based X-ray fluorescence analysis package

NASA Astrophysics Data System (ADS)

Li, Li; Yan, Hanfei; Xu, Wei; Yu, Dantong; Heroux, Annie; Lee, Wah-Keat; Campbell, Stuart I.; Chu, Yong S.

2017-09-01

We developed a python-based fluorescence analysis package (PyXRF) at the National Synchrotron Light Source II (NSLS-II) for the X-ray fluorescence-microscopy beamlines, including Hard X-ray Nanoprobe (HXN), and Submicron Resolution X-ray Spectroscopy (SRX). This package contains a high-level fitting engine, a comprehensive commandline/ GUI design, rigorous physics calculations, and a visualization interface. PyXRF offers a method of automatically finding elements, so that users do not need to spend extra time selecting elements manually. Moreover, PyXRF provides a convenient and interactive way of adjusting fitting parameters with physical constraints. This will help us perform quantitative analysis, and find an appropriate initial guess for fitting. Furthermore, we also create an advanced mode for expert users to construct their own fitting strategies with a full control of each fitting parameter. PyXRF runs single-pixel fitting at a fast speed, which opens up the possibilities of viewing the results of fitting in real time during experiments. A convenient I/O interface was designed to obtain data directly from NSLS-II's experimental database. PyXRF is under open-source development and designed to be an integral part of NSLS-II's scientific computation library.

The reduction of takeoff ground roll by the application of a nose gear jump strut

NASA Technical Reports Server (NTRS)

Eppel, Joseph C.; Maisel, Martin D.; Mcclain, J. Greer; Luce, W.

1994-01-01

A series of flight tests were conducted to evaluate the reduction of takeoff ground roll distance obtainable from a rapid extension of the nose gear strut. The NASA Quiet Short-haul Research Aircraft (QSRA) used for this investigation is a transport-size short take off and landing (STOL) research vehicle with a slightly swept wing that employs the upper surface blowing (USB) concept to attain the high lift levels required for its low-speed, short-field performance. Minor modifications to the conventional nose gear assembly and the addition of a high-pressure pneumatic system and a control system provided the extendable nose gear, or jump strut, capability. The limited flight test program explored the effects of thrust-to-weight ratio, wing loading, storage tank initial pressure, and control valve open time duration on the ground roll distance. The data show that a reduction of takeoff ground roll on the order of 10 percent was achieved with the use of the jump strut, as predicted. Takeoff performance with the jump strut was also found to be essentially independent of the pneumatic supply pressure and was only slightly affected by control valve open time within the range of the parameters examined.

Flight investigation of the use of a nose gear jump strut to reduce takeoff ground roll distance of STOL aircraft

NASA Technical Reports Server (NTRS)

Eppel, Joseph C.; Hardy, Gordon; Martin, James L.

1994-01-01

A series of flight tests was conducted to evaluate the reduction of takeoff ground roll distance obtainable from a rapid extension of the nose gear strut. The NASA Quiet Short-haul Research Aircraft (QSRA) used for this investigation is a transport-size short takeoff and landing (STOL) research vehicle with a slightly swept wing that employs the upper surface blowing (USB) concept to attain the high lift levels required for its low speed, short-field performance. Minor modifications to the conventional nose gear assembly and the addition of a high pressure pneumatic system and a control system provided the extendible nose gear, or 'jump strut,' capability. The limited flight test program explored the effects of thrust-to-weight ratio, storage tank initial pressure, and control valve open time duration on the ground roll distance. The data show that the predicted reduction of takeoff ground roll on the order of 10 percent was achieved with the use of the jump strut. Takeoff performance with the jump strut was also found to be essentially independent of the pneumatic supply pressure and was only slightly affected by control valve open time within the range of the parameters examined.

Microscopic theory of traffic-flow instability governing traffic breakdown at highway bottlenecks: Growing wave of increase in speed in synchronized flow.

PubMed

Kerner, Boris S

2015-12-01

We have revealed a growing local speed wave of increase in speed that can randomly occur in synchronized flow (S) at a highway bottleneck. The development of such a traffic flow instability leads to free flow (F) at the bottleneck; therefore, we call this instability an S→F instability. Whereas the S→F instability leads to a local increase in speed (growing acceleration wave), in contrast, the classical traffic flow instability introduced in the 1950s-1960s and incorporated later in a huge number of traffic flow models leads to a growing wave of a local decrease in speed (growing deceleration wave). We have found that the S→F instability can occur only if there is a finite time delay in driver overacceleration. The initial speed disturbance of increase in speed (called "speed peak") that initiates the S→F instability occurs usually at the downstream front of synchronized flow at the bottleneck. There can be many speed peaks with random amplitudes that occur randomly over time. It has been found that the S→F instability exhibits a nucleation nature: Only when a speed peak amplitude is large enough can the S→F instability occur; in contrast, speed peaks of smaller amplitudes cause dissolving speed waves of a local increase in speed (dissolving acceleration waves) in synchronized flow. We have found that the S→F instability governs traffic breakdown-a phase transition from free flow to synchronized flow (F→S transition) at the bottleneck: The nucleation nature of the S→F instability explains the metastability of free flow with respect to an F→S transition at the bottleneck.

Microscopic theory of traffic-flow instability governing traffic breakdown at highway bottlenecks: Growing wave of increase in speed in synchronized flow

NASA Astrophysics Data System (ADS)

Kerner, Boris S.

2015-12-01

We have revealed a growing local speed wave of increase in speed that can randomly occur in synchronized flow (S) at a highway bottleneck. The development of such a traffic flow instability leads to free flow (F) at the bottleneck; therefore, we call this instability an S →F instability. Whereas the S →F instability leads to a local increase in speed (growing acceleration wave), in contrast, the classical traffic flow instability introduced in the 1950s-1960s and incorporated later in a huge number of traffic flow models leads to a growing wave of a local decrease in speed (growing deceleration wave). We have found that the S →F instability can occur only if there is a finite time delay in driver overacceleration. The initial speed disturbance of increase in speed (called "speed peak") that initiates the S →F instability occurs usually at the downstream front of synchronized flow at the bottleneck. There can be many speed peaks with random amplitudes that occur randomly over time. It has been found that the S →F instability exhibits a nucleation nature: Only when a speed peak amplitude is large enough can the S →F instability occur; in contrast, speed peaks of smaller amplitudes cause dissolving speed waves of a local increase in speed (dissolving acceleration waves) in synchronized flow. We have found that the S →F instability governs traffic breakdown—a phase transition from free flow to synchronized flow (F →S transition) at the bottleneck: The nucleation nature of the S →F instability explains the metastability of free flow with respect to an F →S transition at the bottleneck.

40 CFR Table 7 to Subpart Ggg of... - Wastewater-Inspection and Monitoring Requirements for Waste Management Units

Code of Federal Regulations, 2010 CFR

2010-07-01

... or monitoring Method TANKS: 63.1256(b)(3)(i) Inspect fixed roof and all openings for leaks Initially... openings for leaks Initially Semiannually Visual. 63.1256(c)(2) Inspect surface impoundment for control....1256(d)(1)(ii) Inspect cover and all openings for leaks Initially Semiannually Visual. 63.1256(d)(3)(i...

40 CFR Table 11 to Subpart G of... - Wastewater-Inspection and Monitoring Requirements for Waste Management Units

Code of Federal Regulations, 2010 CFR

2010-07-01

... openings for leaks Initially Semi-annually Visual. 63.133(c) Inspect floating roof in accordance with §§ 63.... Surface impoundments: 63.134(b)(1) Inspect cover and all openings for leaks Initially Semi-annually Visual... for leaks Initially Semi-annually Visual. 63.135(d)(1) Inspect enclosure and all openings for leaks...

Conformational heterogeneity and bubble dynamics in single bacterial transcription initiation complexes

PubMed Central

Duchi, Diego; Gryte, Kristofer; Robb, Nicole C; Morichaud, Zakia; Sheppard, Carol; Wigneshweraraj, Sivaramesh

2018-01-01

Abstract Transcription initiation is a major step in gene regulation for all organisms. In bacteria, the promoter DNA is first recognized by RNA polymerase (RNAP) to yield an initial closed complex. This complex subsequently undergoes conformational changes resulting in DNA strand separation to form a transcription bubble and an RNAP-promoter open complex; however, the series and sequence of conformational changes, and the factors that influence them are unclear. To address the conformational landscape and transitions in transcription initiation, we applied single-molecule Förster resonance energy transfer (smFRET) on immobilized Escherichia coli transcription open complexes. Our results revealed the existence of two stable states within RNAP–DNA complexes in which the promoter DNA appears to adopt closed and partially open conformations, and we observed large-scale transitions in which the transcription bubble fluctuated between open and closed states; these transitions, which occur roughly on the 0.1 s timescale, are distinct from the millisecond-timescale dynamics previously observed within diffusing open complexes. Mutational studies indicated that the σ70 region 3.2 of the RNAP significantly affected the bubble dynamics. Our results have implications for many steps of transcription initiation, and support a bend-load-open model for the sequence of transitions leading to bubble opening during open complex formation. PMID:29177430

Scouts behave as streakers in honeybee swarms

NASA Astrophysics Data System (ADS)

Greggers, Uwe; Schöning, Caspar; Degen, Jacqueline; Menzel, Randolf

2013-08-01

Harmonic radar tracking was used to record the flights of scout bees during takeoff and initial flight path of two honeybee swarms. One swarm remained intact and performed a full flight to a destination beyond the range of the harmonic radar, while a second swarm disintegrated within the range of the radar and most of the bees returned to the queen. The initial stretch of the full flight is characterized by accelerating speed, whereas the disintegrating swarm flew steadily at low speed. The two scouts in the swarm displaying full flight performed characteristic flight maneuvers. They flew at high speed when traveling in the direction of their destination and slowed down or returned over short stretches at low speed. Scouts in the disintegrating swarm did not exhibit the same kind of characteristic flight performance. Our data support the streaker bee hypothesis proposing that scout bees guide the swarm by traveling at high speed in the direction of the new nest site for short stretches of flight and slowing down when reversing flight direction.

STEM@1000mph: Developing Open Educational Resources in a Live Engineering Project

ERIC Educational Resources Information Center

Lanham, John; Howard, Yvonne; Drew, Ben; Johns, Dan

2013-01-01

Higher education institutions are recognising the clear benefits of open educational resources, and academics are engaging with the development of these resources. This paper presents a case study of OERs being developed using the live, current BloodhoundSSC world land speed record project as a basis. The paper outlines the rationale for the…

Slower speed and stronger coupling: adaptive mechanisms of chaos synchronization.

PubMed

Wang, Xiao Fan

2002-06-01

We show that two initially weakly coupled chaotic systems can achieve synchronization by adaptively reducing their speed and/or enhancing the coupling strength. Explicit adaptive algorithms for speed reduction and coupling enhancement are provided. We apply these algorithms to the synchronization of two coupled Lorenz systems. It is found that after a long-time adaptive process, the two coupled chaotic systems can achieve synchronization with almost the minimum required coupling-speed ratio.

Features of Upward Positive Leaders Initiated From Towers in Natural Cloud-to-Ground Lightning Based on Simultaneous High-Speed Videos, Measured Currents, and Electric Fields

NASA Astrophysics Data System (ADS)

Visacro, Silverio; Guimaraes, Miguel; Murta Vale, Maria Helena

2017-12-01

Original simultaneous records of currents, close electric field, and high-speed videos of natural negative cloud-to-ground lightning striking the tower of Morro do Cachimbo Station are used to reveal typical features of upward positive leaders before the attachment, including their initiation and mode of propagation. According to the results, upward positive leaders initiate some hundreds of microseconds prior to the return stroke, while a continuous uprising current of about 4 A and superimposed pulses of a few tens amperes flow along the tower. Upon leader initiation, the electric field measured 50 m away from the tower at ground level is about 60 kV/m. The corresponding average field roughly estimated 0.5 m above the tower top is higher than 0.55 MV/m. As in laboratory experiments, the common propagation mode of upward positive leaders is developing continuously, without steps, from their initiation. Unlike downward negative leaders, upward positive leaders typically do not branch off, though they can bifurcate under the effect of a downward negative leader's secondary branch approaching their lateral surface. The upward positive leader's estimated average two-dimensional propagation speed, in the range of 0.06 × 106 to 0.16 × 106 m/s, has the same order of magnitude as that of downward negative leaders. Apparently, the speed tends to increase just before attachment.

Parallelization of interpolation, solar radiation and water flow simulation modules in GRASS GIS using OpenMP

NASA Astrophysics Data System (ADS)

Hofierka, Jaroslav; Lacko, Michal; Zubal, Stanislav

2017-10-01

In this paper, we describe the parallelization of three complex and computationally intensive modules of GRASS GIS using the OpenMP application programming interface for multi-core computers. These include the v.surf.rst module for spatial interpolation, the r.sun module for solar radiation modeling and the r.sim.water module for water flow simulation. We briefly describe the functionality of the modules and parallelization approaches used in the modules. Our approach includes the analysis of the module's functionality, identification of source code segments suitable for parallelization and proper application of OpenMP parallelization code to create efficient threads processing the subtasks. We document the efficiency of the solutions using the airborne laser scanning data representing land surface in the test area and derived high-resolution digital terrain model grids. We discuss the performance speed-up and parallelization efficiency depending on the number of processor threads. The study showed a substantial increase in computation speeds on a standard multi-core computer while maintaining the accuracy of results in comparison to the output from original modules. The presented parallelization approach showed the simplicity and efficiency of the parallelization of open-source GRASS GIS modules using OpenMP, leading to an increased performance of this geospatial software on standard multi-core computers.

Performance evaluation of OpenFOAM on many-core architectures

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

Brzobohatý, Tomáš; Říha, Lubomír; Karásek, Tomáš, E-mail: tomas.karasek@vsb.cz

In this article application of Open Source Field Operation and Manipulation (OpenFOAM) C++ libraries for solving engineering problems on many-core architectures is presented. Objective of this article is to present scalability of OpenFOAM on parallel platforms solving real engineering problems of fluid dynamics. Scalability test of OpenFOAM is performed using various hardware and different implementation of standard PCG and PBiCG Krylov iterative methods. Speed up of various implementations of linear solvers using GPU and MIC accelerators are presented in this paper. Numerical experiments of 3D lid-driven cavity flow for several cases with various number of cells are presented.

An experimental evaluation of the performance deficit of an aircraft engine starter turbine

NASA Technical Reports Server (NTRS)

Haas, J. E.; Roelke, R. J.; Hermann, P.

1980-01-01

An experimental investigation is presented to determine the aerodynamic performance deficit of a 13.5 - centimeter-tip-diameter aircraft engine starter turbine. The two-phased evaluation comprised both the stator and the stage performance, and the experimental design is described in detail. Data obtained from the investigation of three honeycomb shrouds clearly showed that the filled honeycomb reached a total efficiency of 0.868, 8.2 points higher than the open honeycomb shroud, at design equivalent conditions of speed and blade-jet speed ratio. It was concluded that the use of an open honeycomb shroud caused the large performance deficit for the starter turbine. Further research is suggested to ascertain stator inlet boundary layer measurements.

Sprinting performance of two Iberian fish: Luciobarbus bocagei and Pseudochondrostoma duriense in an open channel flume

USGS Publications Warehouse

Sanz-Ronda, Francisco Javier; Ruiz-Legazpi, Jorge; Bravo-Cordoba, Francisco Javier; Makrakis, Sergio; Castro-Santos, Theodore R.

2015-01-01

This paper presents sprinting data from Iberian barbel (Luciobarbus bocagei) and northern straight-mouth nase (Pseudochondrostoma duriense), volitionally swimming against high velocity flows (1.5, 2.5 and 3 m s−1) in an open channel flume. Swimming endurance and speed greatly exceeded previously published observations with both species attaining swim speeds >20 body lengths s−1. Flow velocity was the primary variable limiting the distance both species were able to traverse. Barbel swam greater distances than nase at higher flow velocities, with longer individuals attaining greater distances than smaller ones. The results challenge established fish passage guidelines, suggesting that in some cases these species are capable of passing much higher velocities than was previously believed.

Frictional Torque on a Rotating Disc

ERIC Educational Resources Information Center

Mungan, Carl E.

2012-01-01

Resistance to motion often includes a dry frictional term independent of the speed of an object and a fluid drag term varying linearly with speed in the viscous limit. (At higher speeds, quadratic drag can also occur.) Here, measurements are performed for an aluminium disc mounted on bearings that is given an initial twist and allowed to spin…

High speed observation of fragment impact initiation of nitromethane charges

NASA Astrophysics Data System (ADS)

Cook, M. D.; Haskins, P. J.; Briggs, R. I.; Cheese, P.; Stennett, C.; Fellows, J.

2000-04-01

Ultra high-speed digital photography has been used to record the onset and build-up of reaction in nitromethane charges that have been impacted by steel fragments. The nitromethane charges were housed in PMMA cylinders and back-lit using conventional flash bulbs. Flat plates of aluminum were glued to one end of the cylinder and PMMA plates to the other. The completed charge was positioned to allow normal impact of the projectiles through the aluminum barrier plate. The events were filmed using an Imacon 468, ultra high-speed digital image system, capable of framing at up to 100 million pictures per second. Using this system it was possible to record detailed photographic information concerning the onset and growth of reaction due to shock initiation of the nitromethane charges. The results obtained to date are consistent with the established concepts for initiation of homogeneous and heterogeneous materials.

The chocolate-colored expanse of Rogers Dry Lake frames the sleek lines of the Boeing / NASA X-48B subscale demonstrator during a test flight at Edwards AFB

NASA Image and Video Library

2007-08-14

Boeing Phantom Works' subscale Blended Wing Body technology demonstration aircraft began its initial flight tests from NASA's Dryden Flight Research Center at Edwards Air Force Base, Calif. in the summer of 2007. The 8.5 percent dynamically scaled unmanned aircraft, designated the X-48B by the Air Force, is designed to mimic the aerodynamic characteristics of a full-scale large cargo transport aircraft with the same blended wing body shape. The initial flight tests focused on evaluation of the X-48B's low-speed flight characteristics and handling qualities. About 25 flights were planned to gather data in these low-speed flight regimes. Based on the results of the initial flight test series, a second set of flight tests was planned to test the aircraft's low-noise and handling characteristics at transonic speeds.

A reliable unipedal stance test for the assessment of balance using a force platform.

PubMed

Ponce-González, J G; Sanchis-Moysi, J; González-Henriquez, J J; Arteaga-Ortiz, R; Calbet, J A L; Dorado, C

2014-02-01

The aim was to develop a unipedal stance test for the assessment of balance using a force platform. A single-leg balance test was conducted in 23 students (mean ± SD) age: 23 ± 3 years) in a standard position limiting the movement of the arms and non-supporting leg. Six attempts, with both the jumping (JL) and the contralateral leg (CL), were performed under 3 conditions: 1) eyes opened; 2) eyes closed; 3) eyes opened and executing a precision task. The same protocol was repeated two-week apart. The mean and the best result of the six attempts performed each day were taken as representative of balance. The speed of the centre of pressure (CP-Speed) showed excellent reliability for the "best result" analysis in all tests (ICCs 0.87-0.97), except in the test with the eyes closed performed on the CL (ICC<0.4). The CP-Speed had better reliability with the "best result" than with the "mean result" analysis (P<0.05), whilst no significant differences were observed between the JL and the CL (P=0.71 and P=0.96 for mean and best results analysis, respectively). A lower dispersion in the Bland and Altman graph was observed with the eyes opened than closed, and the dynamic test. The single-leg stance balance test proposed is a reliable method to assess balance, especially when performed in a static position, with the eyes opened and using the best result of six attempts as reference, independently of the stance leg.

Chitosan production by psychrotolerant Rhizopus oryzae in non-sterile open fermentation conditions.

PubMed

Tasar, Ozden Canli; Erdal, Serkan; Taskin, Mesut

2016-08-01

A new chitosan producing fungus was locally isolated from soil samples collected around Erzurum, Turkey and identified as Rhizopus oryzae PAS 17 (GenBank accession number KU318422.1). Cultivation in low cost non-sterile conditions was achieved by exploiting its ability to grow at low temperature and pH, thus, undesired microbial contamination could be eliminated when appropriate culture conditions (incubation temperature as 15°C and initial pH of the medium as 4.5) were selected. Medium composition and culture conditions were optimized using Taguchi orthogonal array (OA) design of experiment (DOE). An OA layout of L16 (4(5)) was constructed with five most influensive factors at four levels on chitosan production like, carbon source (molasses), metal ion (Mg(2+)), inoculum amount, agitation speed and incubation time. The optimal combinations of factors (molasses, 70ml/l; MgSO4·7H2O, 0.5g/l; inoculum, 6.7×10(6) spores/disc; agitation speed, 150rpm and incubation time, 8days) obtained from the proposed DOE methodology was further validated by analysis of variance (ANOVA) test and the results revealed the increment of chitosan and biomass yields of 14.45 and 8.58 folds from its unoptimized condition, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

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

Zhu, Yi; Cai, Zhonghou; Chen, Pice

Dynamical phase separation during a solid-solid phase transition poses a challenge for understanding the fundamental processes in correlated materials. Critical information underlying a phase transition, such as localized phase competition, is difficult to reveal by measurements that are spatially averaged over many phase seperated regions. The ability to simultanousely track the spatial and temporal evolution of such systems is essential to understanding mesoscopic processes during a phase transition. Using state-of- the-art time-resolved hard x-ray diffraction microscopy, we directly visualize the structural phase progression in a VO 2 film upon photoexcitation. Following a homogenous in-plane optical excitation, the phase transformation ismore » initiated at discrete sites and completed by the growth of one lattice structure into the other, instead of a simultaneous isotropic lattice symmetry change. The time-dependent x-ray diffraction spatial maps show that the in-plane phase progression in laser-superheated VO 2 is via a displacive lattice transformation as a result of relaxation from an excited monoclinic phase into a rutile phase. The speed of the phase front progression is quantitatively measured, which is faster than the process driven by in-plane thermal diffusion but slower than the sound speed in VO 2. Lastly, the direct visualization of localized structural changes in the time domain opens a new avenue to study mesoscopic processes in driven systems.« less

mz5: Space- and Time-efficient Storage of Mass Spectrometry Data Sets*

PubMed Central

Wilhelm, Mathias; Kirchner, Marc; Steen, Judith A. J.; Steen, Hanno

2012-01-01

Across a host of MS-driven-omics fields, researchers witness the acquisition of ever increasing amounts of high throughput MS data and face the need for their compact yet efficiently accessible storage. Addressing the need for an open data exchange format, the Proteomics Standards Initiative and the Seattle Proteome Center at the Institute for Systems Biology independently developed the mzData and mzXML formats, respectively. In a subsequent joint effort, they defined an ontology and associated controlled vocabulary that specifies the contents of MS data files, implemented as the newer mzML format. All three formats are based on XML and are thus not particularly efficient in either storage space requirements or read/write speed. This contribution introduces mz5, a complete reimplementation of the mzML ontology that is based on the efficient, industrial strength storage backend HDF5. Compared with the current mzML standard, this strategy yields an average file size reduction to ∼54% and increases linear read and write speeds ∼3–4-fold. The format is implemented as part of the ProteoWizard project and is available under a permissive Apache license. Additional information and download links are available from http://software.steenlab.org/mz5. PMID:21960719

Combined effects of speed and directional change on postural adjustments during gait initiation.

PubMed

Corbeil, Philippe; Anaka, Evelyn

2011-10-01

The study of gait initiation (GI) has primarily focused on gait initiated in a forward direction, however, in everyday life, GI is often combined with a directional change. Ten young adults initiated gait with their right foot in four directions (to the left: -15°, straight ahead: 0°, to the right: 15° and 30°) at self-selected and fast gait speeds. The relationship between starting direction of GI and the lateral center of foot pressure displacement for normal (r(2)=0.57) and fast gait speed (r(2)=0.75) indicated that the lateral component plays an important role with regards to controlling the desired direction of gait. At the first step of the swing limb, the progression velocity of the center of mass (CM) remained slower for the 30° condition only, whereas no difference was found between directions for CM velocity perpendicular to the intended direction. These results suggest that postural adjustments are scaled to initiate gait in a predetermined direction. By the first step, the orientation of CM is toward the intended direction of gait, however, when gait is initiated in combination with a large change in direction, additional adjustments may be required to reach the intended progression velocity. Copyright © 2011 Elsevier Ltd. All rights reserved.

Dextrose monohydrate as a non-animal sourced alternative diluent in high shear wet granulation tablet formulations.

PubMed

Mitra, Biplob; Wolfe, Chad; Wu, Sy-Juen

2018-05-01

The feasibility of dextrose monohydrate as a non-animal sourced diluent in high shear wet granulation (HSWG) tablet formulations was determined. Impacts of granulation solution amount and addition time, wet massing time, impeller speed, powder and solution binder, and dry milling speed and screen opening size on granule size, friability and density, and tablet solid fraction (SF) and tensile strength (TS) were evaluated. The stability of theophylline tablets TS, disintegration time (DT) and in vitro dissolution were also studied. Following post-granulation drying at 60 °C, dextrose monohydrate lost 9% water and converted into the anhydrate form. Higher granulation solution amounts and faster addition, faster impeller speeds, and solution binder produced larger, denser and stronger (less friable) granules. All granules were compressed into tablets with acceptable TS. Contrary to what is normally observed, denser and larger granules (at ≥21% water level) produced tablets with a higher TS. The TS of the weakest tablets increased the most after storage at both 25 °C/60% RH and 40 °C/75% RH. Tablet DT was higher for stronger granules and after storage. Tablet dissolution profiles for 21% or less water were comparable and did not change on stability. However, the dissolution profile for tablets prepared with 24% water was slower initially and continued to decrease on stability. The results indicate a granulation water amount of not more than 21% is required to achieve acceptable tablet properties. This study clearly demonstrated the utility of dextrose monohydrate as a non-animal sourced diluent in a HSWG tablet formulation.

Determination of feature generation methods for PTZ camera object tracking

NASA Astrophysics Data System (ADS)

Doyle, Daniel D.; Black, Jonathan T.

2012-06-01

Object detection and tracking using computer vision (CV) techniques have been widely applied to sensor fusion applications. Many papers continue to be written that speed up performance and increase learning of artificially intelligent systems through improved algorithms, workload distribution, and information fusion. Military application of real-time tracking systems is becoming more and more complex with an ever increasing need of fusion and CV techniques to actively track and control dynamic systems. Examples include the use of metrology systems for tracking and measuring micro air vehicles (MAVs) and autonomous navigation systems for controlling MAVs. This paper seeks to contribute to the determination of select tracking algorithms that best track a moving object using a pan/tilt/zoom (PTZ) camera applicable to both of the examples presented. The select feature generation algorithms compared in this paper are the trained Scale-Invariant Feature Transform (SIFT) and Speeded Up Robust Features (SURF), the Mixture of Gaussians (MoG) background subtraction method, the Lucas- Kanade optical flow method (2000) and the Farneback optical flow method (2003). The matching algorithm used in this paper for the trained feature generation algorithms is the Fast Library for Approximate Nearest Neighbors (FLANN). The BSD licensed OpenCV library is used extensively to demonstrate the viability of each algorithm and its performance. Initial testing is performed on a sequence of images using a stationary camera. Further testing is performed on a sequence of images such that the PTZ camera is moving in order to capture the moving object. Comparisons are made based upon accuracy, speed and memory.

Guaranteeing safety in spatially situated agents

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

Kohout, R.C.; Hendler, J.A.; Musliner, D.J.

1996-12-31

{open_quote}Mission-critical{close_quotes} systems, which include such diverse applications as nuclear power plant controllers, {open_quotes}fly-by-wire{close_quotes} airplanes, medical care and monitoring systems, and autonomous mobile vehicles, are characterized by the fact that system failure is potentially catastrophic. The high cost of failure justifies the expenditure of considerable effort at design-time in order to guarantee the correctness of system behavior. This paper examines the problem of guaranteeing safety in a well studied class of robot motion problems known as the {open_quotes}asteroid avoidance problem.{close_quotes} We establish necessary and sufficient conditions for ensuring safety in the simple version of this problem which occurs most frequently inmore » the literature, as well as sufficient conditions for a more general and realistic case. In doing so, we establish functional relationships between the number, size and speed of obstacles, the robot`s maximum speed and the conditions which must be maintained in order to ensure safety.« less

[An analysis of nutritional and harmful components of vegetables grown in plastic greenhouses].

PubMed

Yao, H; Yan, W; Li, G; Chen, Y; Guo, W; Wang, G; Xu, Z; Feng, C; Liu, K; Jin, D

1999-09-01

To study the changes in nutritional and harmful components of vegetables grown in plastic greenhouses. In plastic greenhouses, microclimate and air concentrations of carbon monoxide, carbon dioxide, fluoride and respirable particulate were measured, and chlorophyll, total sugar, crude fiber, nitrite, fluoride, arsenic and some mineral elements in vegetables were determined as compared with those grown in the open-air fields. Greenhouse appeared a lower wind speed and darker illumination. Contents of chlorophyll a an b, total chlorophyll, reduced vitamin C, crude fiber in vegetables grown in greenhouse all were lower than those grown in open-air fields. Contents of potassium, calcium, magnesium, iron, zinc, copper and phosphorous were all lower in the vegetables grown in greenhouse than those grown in open-air fields. The contents of chlorophyll reducing Vitamin C. Lower wind speed and inadequate illumination in greenhouse affected photosynthesis and uptake of water in vegetables causing changes in their nutritional components. But, no contamination of burning coal was found in vegetables grown in greenhouse.

Magnetically-focusing biochip structures for high-speed active biosensing with improved selectivity.

PubMed

Yoo, Haneul; Lee, Dong Jun; Kim, Daesan; Park, Juhun; Chen, Xing; Hong, Seunghun

2018-06-29

We report a magnetically-focusing biochip structure enabling a single layered magnetic trap-and-release cycle for biosensors with an improved detection speed and selectivity. Here, magnetic beads functionalized with specific receptor molecules were utilized to trap target molecules in a solution and transport actively to and away from the sensor surfaces to enhance the detection speed and reduce the non-specific bindings, respectively. Using our method, we demonstrated the high speed detection of IL-13 antigens with the improved detection speed by more than an order of magnitude. Furthermore, the release step in our method was found to reduce the non-specific bindings and improve the selectivity and sensitivity of biosensors. This method is a simple but powerful strategy and should open up various applications such as ultra-fast biosensors for point-of-care services.

Magnetically-focusing biochip structures for high-speed active biosensing with improved selectivity

NASA Astrophysics Data System (ADS)

Yoo, Haneul; Lee, Dong Jun; Kim, Daesan; Park, Juhun; Chen, Xing; Hong, Seunghun

2018-06-01

We report a magnetically-focusing biochip structure enabling a single layered magnetic trap-and-release cycle for biosensors with an improved detection speed and selectivity. Here, magnetic beads functionalized with specific receptor molecules were utilized to trap target molecules in a solution and transport actively to and away from the sensor surfaces to enhance the detection speed and reduce the non-specific bindings, respectively. Using our method, we demonstrated the high speed detection of IL-13 antigens with the improved detection speed by more than an order of magnitude. Furthermore, the release step in our method was found to reduce the non-specific bindings and improve the selectivity and sensitivity of biosensors. This method is a simple but powerful strategy and should open up various applications such as ultra-fast biosensors for point-of-care services.

Economy, Movement Dynamics, and Muscle Activity of Human Walking at Different Speeds.

PubMed

Raffalt, P C; Guul, M K; Nielsen, A N; Puthusserypady, S; Alkjær, T

2017-03-08

The complex behaviour of human walking with respect to movement variability, economy and muscle activity is speed dependent. It is well known that a U-shaped relationship between walking speed and economy exists. However, it is an open question if the movement dynamics of joint angles and centre of mass and muscle activation strategy also exhibit a U-shaped relationship with walking speed. We investigated the dynamics of joint angle trajectories and the centre of mass accelerations at five different speeds ranging from 20 to 180% of the predicted preferred speed (based on Froude speed) in twelve healthy males. The muscle activation strategy and walking economy were also assessed. The movement dynamics was investigated using a combination of the largest Lyapunov exponent and correlation dimension. We observed an intermediate stage of the movement dynamics of the knee joint angle and the anterior-posterior and mediolateral centre of mass accelerations which coincided with the most energy-efficient walking speed. Furthermore, the dynamics of the joint angle trajectories and the muscle activation strategy was closely linked to the functional role and biomechanical constraints of the joints.

Strain actuated aeroelastic control

NASA Technical Reports Server (NTRS)

Lazarus, Kenneth B.

1992-01-01

Viewgraphs on strain actuated aeroelastic control are presented. Topics covered include: structural and aerodynamic modeling; control law design methodology; system block diagram; adaptive wing test article; bench-top experiments; bench-top disturbance rejection: open and closed loop response; bench-top disturbance rejection: state cost versus control cost; wind tunnel experiments; wind tunnel gust alleviation: open and closed loop response at 60 mph; wind tunnel gust alleviation: state cost versus control cost at 60 mph; wind tunnel command following: open and closed loop error at 60 mph; wind tunnel flutter suppression: open loop flutter speed; and wind tunnel flutter suppression: closed loop state cost curves.

FTA low-speed urban Maglev research program : updated lessons learned.

DOT National Transportation Integrated Search

2012-11-01

In 1999, the Federal Transit Administration (FTA) initiated the Low-Speed Urban Magnetic Levitation (Urban Maglev) Program to develop magnetic levitation technology that offers a cost-effective, reliable, and environmentally-sound transit option for ...

Littoral Combat Ship Open Ocean Anti-Submarine Warfare

DTIC Science & Technology

2014-06-01

maintain stealth and its defense in order to properly conduct an attack on a surface vessel (Sternhell and Thorndike 2014, 102). This statement...its target, the surface combatants can counter by increasing their speed (Sternhell and Thorndike 2014). While the maximum speed of the current...120316_PS.pdf Sternhell, Charles M, and Alan M Thorndike . 2014. “Antisubmarine Warfare in World War II.” CNA Analysis & Solutions. Accessed April 14, 2014

Speed and Agility: How Defense Acquisition Can Enable Innovation

DTIC Science & Technology

2016-04-30

an example of an innovation partnership, Airbus partnered with micro- manufacturing innovator Local Motors to co-create commercial drones using the... Airbus Quadcruiser’s hybrid concept as the starting design. Local Motors recently released its Strati roadster, the world’s first 3D-printed car... Airbus sought to “speed-up development and manufacturing in aerospace through an open competition based on co-creation and micro- manufacturing.” The

Public Data Set: Erratum: "Multi-point, high-speed passive ion velocity distribution diagnostic on the Pegasus Toroidal Experiment" [Rev. Sci. Instrum. 83, 10D516 (2012)

DOE Data Explorer

Burke, Marcus G. [University of Wisconsin-Madison] (ORCID:0000000176193724); Fonck, Raymond J. [University of Wisconsin-Madison] (ORCID:0000000294386762); Bongard, Michael W. [University of Wisconsin-Madison] (ORCID:0000000231609746); Schlossberg, David J. [University of Wisconsin-Madison] (ORCID:0000000287139448); Winz, Gregory R. [University of Wisconsin-Madison] (ORCID:0000000177627184)

2016-07-18

This data set contains openly-documented, machine readable digital research data corresponding to figures published in M.G. Burke et al., 'Erratum: "Multi-point, high-speed passive ion velocity distribution diagnostic on the Pegasus Toroidal Experiment" [Rev. Sci. Instrum. 83, 10D516 (2012)],' Rev. Sci. Instrum. 87, 079902 (2016).

Landing spacecraft on Mars and other planets: An opportunity to apply introductory physics

NASA Astrophysics Data System (ADS)

Withers, Paul

2013-08-01

The Curiosity rover safely landed on Mars after "seven minutes of terror" passing through the Martian atmosphere. In order to land safely, Curiosity had to decelerate from speeds of several kilometers per second and reach zero speed exactly upon touching down on the surface. This was accomplished by a combination of atmospheric drag on the enclosed spacecraft during the initial hypersonic entry, deployment of a large parachute, and retrorockets. Here, we use the familiar concepts of introductory physics to explain why all three of these factors were necessary to ensure a safe landing. In particular, we analyze the initial deceleration of a spacecraft at high altitudes, its impact speed if a parachute is not used, its impact speed if a parachute is used, and the duration of its descent on a parachute, using examples from Curiosity and other missions.

Behavioural system identification of visual flight speed control in Drosophila melanogaster

PubMed Central

Rohrseitz, Nicola; Fry, Steven N.

2011-01-01

Behavioural control in many animals involves complex mechanisms with intricate sensory-motor feedback loops. Modelling allows functional aspects to be captured without relying on a description of the underlying complex, and often unknown, mechanisms. A wide range of engineering techniques are available for modelling, but their ability to describe time-continuous processes is rarely exploited to describe sensory-motor control mechanisms in biological systems. We performed a system identification of visual flight speed control in the fruitfly Drosophila, based on an extensive dataset of open-loop responses previously measured under free flight conditions. We identified a second-order under-damped control model with just six free parameters that well describes both the transient and steady-state characteristics of the open-loop data. We then used the identified control model to predict flight speed responses after a visual perturbation under closed-loop conditions and validated the model with behavioural measurements performed in free-flying flies under the same closed-loop conditions. Our system identification of the fruitfly's flight speed response uncovers the high-level control strategy of a fundamental flight control reflex without depending on assumptions about the underlying physiological mechanisms. The results are relevant for future investigations of the underlying neuromotor processing mechanisms, as well as for the design of biomimetic robots, such as micro-air vehicles. PMID:20525744

Building an open-source robotic stereotaxic instrument.

PubMed

Coffey, Kevin R; Barker, David J; Ma, Sisi; West, Mark O

2013-10-29

This protocol includes the designs and software necessary to upgrade an existing stereotaxic instrument to a robotic (CNC) stereotaxic instrument for around $1,000 (excluding a drill), using industry standard stepper motors and CNC controlling software. Each axis has variable speed control and may be operated simultaneously or independently. The robot's flexibility and open coding system (g-code) make it capable of performing custom tasks that are not supported by commercial systems. Its applications include, but are not limited to, drilling holes, sharp edge craniotomies, skull thinning, and lowering electrodes or cannula. In order to expedite the writing of g-coding for simple surgeries, we have developed custom scripts that allow individuals to design a surgery with no knowledge of programming. However, for users to get the most out of the motorized stereotax, it would be beneficial to be knowledgeable in mathematical programming and G-Coding (simple programming for CNC machining). The recommended drill speed is greater than 40,000 rpm. The stepper motor resolution is 1.8°/Step, geared to 0.346°/Step. A standard stereotax has a resolution of 2.88 μm/step. The maximum recommended cutting speed is 500 μm/sec. The maximum recommended jogging speed is 3,500 μm/sec. The maximum recommended drill bit size is HP 2.

Behavioural system identification of visual flight speed control in Drosophila melanogaster.

PubMed

Rohrseitz, Nicola; Fry, Steven N

2011-02-06

Behavioural control in many animals involves complex mechanisms with intricate sensory-motor feedback loops. Modelling allows functional aspects to be captured without relying on a description of the underlying complex, and often unknown, mechanisms. A wide range of engineering techniques are available for modelling, but their ability to describe time-continuous processes is rarely exploited to describe sensory-motor control mechanisms in biological systems. We performed a system identification of visual flight speed control in the fruitfly Drosophila, based on an extensive dataset of open-loop responses previously measured under free flight conditions. We identified a second-order under-damped control model with just six free parameters that well describes both the transient and steady-state characteristics of the open-loop data. We then used the identified control model to predict flight speed responses after a visual perturbation under closed-loop conditions and validated the model with behavioural measurements performed in free-flying flies under the same closed-loop conditions. Our system identification of the fruitfly's flight speed response uncovers the high-level control strategy of a fundamental flight control reflex without depending on assumptions about the underlying physiological mechanisms. The results are relevant for future investigations of the underlying neuromotor processing mechanisms, as well as for the design of biomimetic robots, such as micro-air vehicles.

Setback Distances as a Conservation Tool in Wildlife-Human Interactions: Testing Their Efficacy for Birds Affected by Vehicles on Open-Coast Sandy Beaches

PubMed Central

Schlacher, Thomas A.; Weston, Michael A.; Lynn, David; Connolly, Rod M.

2013-01-01

In some wilderness areas, wildlife encounter vehicles disrupt their behaviour and habitat use. Changing driver behaviour has been proposed where bans on vehicle use are politically unpalatable, but the efficacy of vehicle setbacks and reduced speeds remains largely untested. We characterised bird-vehicle encounters in terms of driver behaviour and the disturbance caused to birds, and tested whether spatial buffers or lower speeds reduced bird escape responses on open beaches. Focal observations showed that: i) most drivers did not create sizeable buffers between their vehicles and birds; ii) bird disturbance was frequent; and iii) predictors of probability of flushing (escape) were setback distance and vehicle type (buses flushed birds at higher rates than cars). Experiments demonstrated that substantial reductions in bird escape responses required buffers to be wide (> 25 m) and vehicle speeds to be slow (< 30 km h-1). Setback distances can reduce impacts on wildlife, provided that they are carefully designed and derived from empirical evidence. No speed or distance combination we tested, however, eliminated bird responses. Thus, while buffers reduce response rates, they are likely to be much less effective than vehicle-free zones (i.e. beach closures), and rely on changes to current driver behaviour. PMID:24039711

Control quantum evolution speed of a single dephasing qubit for arbitrary initial states via periodic dynamical decoupling pulses.

PubMed

Song, Ya-Ju; Tan, Qing-Shou; Kuang, Le-Man

2017-03-08

We investigate the possibility to control quantum evolution speed of a single dephasing qubit for arbitrary initial states by the use of periodic dynamical decoupling (PDD) pulses. It is indicated that the quantum speed limit time (QSLT) is determined by initial and final quantum coherence of the qubit, as well as the non-Markovianity of the system under consideration during the evolution when the qubit is subjected to a zero-temperature Ohmic-like dephasing reservoir. It is shown that final quantum coherence of the qubit and the non-Markovianity of the system can be modulated by PDD pulses. Our results show that for arbitrary initial states of the dephasing qubit with non-vanishing quantum coherence, PDD pulses can be used to induce potential acceleration of the quantum evolution in the short-time regime, while PDD pulses can lead to potential speedup and slow down in the long-time regime. We demonstrate that the effect of PDD on the QSLT for the Ohmic or sub-Ohmic spectrum (Markovian reservoir) is much different from that for the super-Ohmic spectrum (non-Markovian reservoir).

Phenotypic plasticity as an adaptation to a functional trade-off

PubMed Central

Yi, Xiao; Dean, Antony M

2016-01-01

We report the evolution of a phenotypically plastic behavior that circumvents the hardwired trade-off that exists when resources are partitioned between growth and motility in Escherichia coli. We propagated cultures in a cyclical environment, alternating between growth up to carrying capacity and selection for chemotaxis. Initial adaptations boosted overall swimming speed at the expense of growth. The effect of the trade-off was subsequently eased through a change in behavior; while individual cells reduced motility during exponential growth, the faction of the population that was motile increased as the carrying capacity was approached. This plastic behavior was produced by a single amino acid replacement in FliA, a regulatory protein central to the chemotaxis network. Our results illustrate how phenotypic plasticity potentiates evolvability by opening up new regions of the adaptive landscape. DOI: http://dx.doi.org/10.7554/eLife.19307.001 PMID:27692064

FIAP Forum on Entrepreneurship in Physics

NASA Astrophysics Data System (ADS)

2015-03-01

With the changes in science as globalization has taken root, the future role of physicists becoming a part of the industrial physics community is more imperative. When 80% of graduating physicists will not be employed in academic positions, and 50% of all jobs for these physicists will be industrial sector, the importance of bringing our next generation of scientists up to speed on industrial applications is becoming much more important with the rapid, world-wide development of technology. FIAP is initiating a forum on entrepreneurship as a major role for the next generation of scientists. As physicists are problem solvers and the entrepreneurial experience is all about problem solving: whether involving technology, building a team, or financing a business. This forum seeks to link successful entrepreneurial physicists with the upcoming generation, through the dissemination of their global expertise and experience. The forum will consist of a panel discussion and then be open to question and answers from the audience.

Deep fiber networks: new ready-to-deploy architectures yield technical and economic benefits

NASA Astrophysics Data System (ADS)

Sipes, Donald L., Jr.; Loveless, Robert

2001-07-01

The advent of digital technology in HFC networks has opened up a myriad of opportunities for MSOs. The introduction of these advanced services comes at a cost: namely, the need for increased capacity; and especially increased reusable bandwidth. In HFC networks all services are ostensibly broadcast: the prime difference between services being the footprint over which these services are broadcast. Channel lineups for broadcast video services typically cover the largest are. Advertising zones are typically second, usually on the order of a typical 20K home hub. For initial penetrations for high speed data services such as cable modems, a typical hub site will be divided into several sectors using a single 6 MHz channel. Telephony services are broadcast over the smallest area, typically a 6 MHz channel for each node. Naturally as penetration of these services increase, the broadcast area for each will also decrease.

Impact of an emergency medicine pharmacist on initial antibiotic prophylaxis for open fractures in trauma patients.

PubMed

Harvey, Somer; Brad Hall, A; Wilson, Kayla

2018-02-01

Targeted antibiotic treatment reduces the infection risk of open fractures when soft tissue and bone are exposed to the environment. The risk of infection increases with higher degrees of injury. The Gustilo-Anderson system was developed to identify the degree of injury of open fractures and can be utilized to guide initial antibiotic therapy. Few studies have been published evaluating the potential impact of emergency medicine pharmacists in trauma, and currently no study has evaluated a pharmacist's influence on antibiotic selection and timing for open fractures. The objective of this study was to determine the impact of an emergency medicine pharmacist on initial antibiotic selection and timing in trauma patients with open fractures. This was a retrospective cohort study. Trauma alerts with open fractures from May 1, 2014 to June 30, 2016 were eligible for inclusion. The primary outcome was to determine if pharmacist participation during trauma resuscitation was associated with an increased proportion of initial antibiotic selection meeting guideline recommendations. The secondary outcome was the door-to-antibiotic administration time during resuscitation. Initial prophylactic antibiotic recommendations were met in 81% of trauma resuscitations when a pharmacist was present versus 47% without a pharmacist present (p<0.01). The median door-to-antibiotic time was 14min in the PHARM group versus 20min in the NO-PHARM group (p=0.02). The participation of an EM pharmacist during initial trauma resuscitation resulted in improved initial antibiotic selection and faster door-to-antibiotic administration times in trauma patients with open fractures. Copyright © 2017 Elsevier Inc. All rights reserved.

Summary and recent results from the NASA advanced High Speed Propeller Research Program

NASA Technical Reports Server (NTRS)

Mitchell, G. A.; Mikkelson, D. C.

1982-01-01

Advanced high-speed propellers offer large performance improvements for aircraft that cruise in the Mach 0.7 to 0.8 speed regime. The current status of the NASA research program on high-speed propeller aerodynamics, acoustics, and aeroelastics is described. Recent wind tunnel results for five 8- to 10-blade advanced models are compared with analytical predictions. Test results show that blade sweep was important in achieving net efficiencies near 80 percent at Mach 0.8 and reducing near-field cruise noise by dB. Lifting line and lifting surface aerodynamic analysis codes are under development and some initial lifting line results are compared with propeller force and probe data. Some initial laser velocimeter measurements of the flow field velocities of an 8-bladed 45 deg swept propeller are shown. Experimental aeroelastic results indicate that cascade effects and blade sweep strongly affect propeller aeroelastic characteristics. Comparisons of propeller near-field noise data with linear acoustic theory indicate that the theory adequate predicts near-field noise for subsonic tip speeds but overpredicts the noise for supersonic tip speeds. Potential large gains in propeller efficiency of 7 to 11 percent at Mach 0.8 may be possible with advanced counter-rotation propellers.

[Hypothesis on the equilibrium point and variability of amplitude, speed and time of single-joint movement].

PubMed

Latash, M; Gottleib, G

1990-01-01

Problems of single-joint movement variability are analysed in the framework of the equilibrium-point hypothesis (the lambda-model). Control of the movements is described with three parameters related to movement amplitude speed, and time. Three strategies emerge from this description. Only one of them is likely to lead to a Fitts' type speed-accuracy trade-off. Experiments were performed to test one of the predictions of the model. Subjects performed identical sets of single-joint fast movements with open or closed eyes and some-what different instructions. Movements performed with closed eyes were characterized with higher peak speeds and unchanged variability in seeming violation of the Fitt's law and in a good correspondence to the model.

Terahertz electrical writing speed in an antiferromagnetic memory

PubMed Central

Kašpar, Zdeněk; Campion, Richard P.; Baumgartner, Manuel; Sinova, Jairo; Kužel, Petr; Müller, Melanie; Kampfrath, Tobias

2018-01-01

The speed of writing of state-of-the-art ferromagnetic memories is physically limited by an intrinsic gigahertz threshold. Recently, realization of memory devices based on antiferromagnets, in which spin directions periodically alternate from one atomic lattice site to the next has moved research in an alternative direction. We experimentally demonstrate at room temperature that the speed of reversible electrical writing in a memory device can be scaled up to terahertz using an antiferromagnet. A current-induced spin-torque mechanism is responsible for the switching in our memory devices throughout the 12-order-of-magnitude range of writing speeds from hertz to terahertz. Our work opens the path toward the development of memory-logic technology reaching the elusive terahertz band. PMID:29740601

Experimental protocols for and studies of the effects of surface passivation and water isotopes on the gliding speed of microtubules propelled by kinesin-1

NASA Astrophysics Data System (ADS)

Maloney, Roger Andrew

This dissertation explores how the kinesin-1 and microtubule system is affected by surface passivation and water isotopes. Surface passivation was found to affect the gliding speed that microtubules exhibit in the gliding motility assay and the lengths of microtubules supported by the passivation. It was also found that gliding speeds of microtubules are very sensitive to temperature changes. Studies changing the water isotope were a first attempt to investigate if changing the solvent changed the osmotic pressure of the solution kinesin and microtubules were in. No osmotic pressure changes were observed, however, the experiments using different isotopes of water did illuminate the possibility that kinesin may be sensitive to viscosity changes in the solvent. This experiment also suggests further experiments that can be specifically designed to probe osmotic pressure changes. This thesis was also the first thesis ever, to the best of the author's knowledge, to be done in a completely open format. All information and notebook entries that are related to it, as well as the thesis itself, can be found on the website OpenWetWare. The thesis can also be found there including all the different versions that went into its editing. The philosophy and process of making data open and accessible to every one is also discussed.

Modeling and analyzing traffic safety perceptions: An application to the speed limit reduction pilot project in Edmonton, Alberta.

PubMed

El-Basyouny, Karim; El-Bassiouni, Mohamed Yahia

2013-03-01

To address the speeding problem in residential areas, the City of Edmonton initiated a pilot project to reduce the posted speed limit from 50km/h to 40km/h within six residential communities. This paper investigates the community perceptions of traffic safety within the six pilot communities in two phases: prior to project initiation (pre-pilot) and following the end of the project (post-pilot). This objective was accomplished by analyzing the results of two random dialing telephone surveys comprising 300 residents each. A preliminary analysis showed compatible demographic configurations for the two samples and confirmed that the residents were aware of both the posted speed limits and the adopted speed management controls. For the confirmatory factor analysis (CFA), a two-group (pre-pilot and post-pilot) three-factor model was used to assess the residents' perceptions of the speeding behavior (Speeding), their concerns about traffic safety issues (Concerns), and their perceptions of traffic safety (Safety). Comparing the CFA results of the post-pilot survey versus those of the pre-pilot survey, it was evident that there was a significant decrease in Speeding and Concerns accompanied by a significant increase in Safety. A structural equations model (SEM) was also fitted to the data in order to assess the impact of Speeding and Concerns on Safety. The results showed that Concerns increase significantly with Speeding, and that both factors have significant negative impacts on Safety. However, while the impact of Concerns on Safety was direct, that of Speeding on Safety was largely indirect (i.e., mediated through Concerns). Overall, the multivariate analysis has demonstrated that the pilot project was successful in improving the residents' perceptions of traffic safety in their community. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

The relative temporal sequence of decline in mobility and cognition among initially unimpaired older adults: Results from the Baltimore Longitudinal Study of Aging.

PubMed

Tian, Qu; An, Yang; Resnick, Susan M; Studenski, Stephanie

2017-05-01

most older individuals who experience mobility decline, also show cognitive decline, but whether cognitive decline precedes or follows mobility limitation is not well understood. examine the temporal sequence of mobility and cognition among initially unimpaired older adults. mobility and cognition were assessed every 2 years for 6 years in 412 participants aged ≥60 with initially unimpaired cognition and gait speed. Using autoregressive models, accounting for the dependent variable from the prior assessment, baseline age, sex, body mass index and education, we examine the temporal sequence of change in mobility (6 m usual gait speed, 400 m fast walk time) and executive function (visuoperceptual speed: Digit Symbol Substitution Test (DSST); cognitive flexibility: Trail Making Test part B (TMT-B)) or memory (California Verbal Learning Test (CVLT) immediate, short-delay, long-delay). there was a bidirectional relationship over time between slower usual gait speed and both poorer DSST and TMT-B scores (Bonferroni-corrected P < 0.005). In contrast, slower 400 m fast walk time predicted subsequent poorer DSST, TMT-B, CVLT immediate recall and CVLT short-delay scores (P < 0.005), while these measures did not predict subsequent 400 m fast walk time (P > 0.005). among initially unimpaired older adults, the temporal relationship between usual gait speed and executive function is bidirectional, with each predicting change in the other, while poor fast walking performance predicts future executive function and memory changes but not vice versa. Challenging tasks like the 400 m walk appear superior to usual gait speed for predicting executive function and memory change in unimpaired older adults. Published by Oxford University Press on behalf of the British Geriatrics Society 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Effects of Time of Day and Sleep Deprivation on Motorcycle-Driving Performance

PubMed Central

Bougard, Clément; Espié, Stéphane; Larnaudie, Bruno; Moussay, Sébastien; Davenne, Damien

2012-01-01

The aim of this study was to investigate whether motorcycle handling capabilities – measured by means of the efficiency of emergency manoeuvres – were dependent on prior sleep deprivation and time of day. Twelve male participants voluntarily took part in four test sessions, starting at 6 a.m., 10 a.m., 2 p.m., and 6 p.m., following a night either with or without sleep. Each test session comprised temperature and sleepiness measurements, before three different types of motorcycling tests were initiated: (1) stability in straight ahead riding at low speed (in “slow motion” mode and in “brakes and clutch” mode), (2) emergency braking and (3) crash avoidance tasks performed at 20 kph and 40 kph. The results indicate that motorcycle control at low speed depends on time of day, with an improvement in performance throughout the day. Emergency braking performance is affected at both speeds by time of day, with poorer performance (longer total stopping distance, reaction time and braking distance) in the morning, and also by sleep deprivation, from measurements obtained at 40 kph (incorrect initial speed). Except for a tendency observed after the sleepless night to deviate from the initial speed, it seems that crash avoidance capabilities are quite unaffected by the two disturbance factors. Consequently, some motorcycle handling capabilities (stability at low speed and emergency braking) change in the same way as the diurnal fluctuation observed in body temperature and sleepiness, whereas for others (crash avoidance) the participants were able to maintain their initial performance level despite the high levels of sleepiness recorded after a sleepless night. Motorcycle riders have to be aware that their handling capabilities are limited in the early morning and/or after sleep deprivation. Both these situations can increase the risk of falls and of being involved in a road accident. PMID:22761881

[Differences in anticipatory postural adjustments between self-generated and triggered gait initiation in 20 healthy subjects].

PubMed

Delval, A; Krystkowiak, P; Blatt, J-L; Labyt, E; Destée, A; Derambure, P; Defebvre, L

2005-01-01

Preparation of upper-limb movements differs between self-paced and triggered conditions. This study analyzed the anticipatory postural adjustments (APAs) of gait initiation in normal subjects in 2 conditions: self-generated and triggered by a "beep" sound. We recorded kinematic, spatiotemporal parameters of the first two steps by means of video motion analysis (6 infrared cameras), and kinetic parameters (using a force platform and the optoelectronic system) in 20 normal subjects. Two conditions: 1) self-generated initiation; and 2) initiation triggered by a "beep" sound were studied to evaluate the APA phase, by recording kinetic data (duration of the APAs, trajectory of the center of pressure, speed and trajectory of the center of mass). Kinematic data (first and second step speed, length and duration) were also recorded. First step speed and length were increased in self-paced gait initiation compared to triggered gait initiation in controls. We found no difference between the 2 conditions in terms of second step kinematic data. It was caused by a significant difference between the 2 conditions for the temporal characteristics of anticipatory postural adjustments (APAs) in the initiation of the first step, which was longer when normal subjects performed self-generated gait initiation. The trajectory of center of pressure and center of mass remained the same in the 2 conditions. APAs of gait initiation process are delayed under self-paced condition, although they do not differ qualitatively between reaction time and self-paced condition. Neuphysiological support of self-generated movement could explain these differences.

FTA Low-speed urban maglev research program lessons learned : March 2009.

DOT National Transportation Integrated Search

2009-03-01

In 1999, the Federal Transit Administration initiated the Low-Speed Urban Magnetic Levitation (UML) Program to develop magnetic levitation technology that offers a cost effective, reliable, and environmentally sound transit option for urban mass tran...

The Challenge of Evaluating the Intensity of Short Actions in Soccer: A New Methodological Approach Using Percentage Acceleration.

PubMed

Sonderegger, Karin; Tschopp, Markus; Taube, Wolfgang

2016-01-01

There are several approaches to quantifying physical load in team sports using positional data. Distances in different speed zones are most commonly used. Recent studies have used acceleration data in addition in order to take short intense actions into account. However, the fact that acceleration decreases with increasing initial running speed is ignored and therefore introduces a bias. The aim of our study was to develop a new methodological approach that removes this bias. For this purpose, percentage acceleration was calculated as the ratio of the maximal acceleration of the action (amax,action) and the maximal voluntary acceleration (amax) that can be achieved for a particular initial running speed (percentage acceleration [%] = amax,action / amax * 100). To define amax, seventy-two highly trained junior male soccer players (17.1 ± 0.6 years) completed maximal sprints from standing and three different constant initial running speeds (vinit; trotting: ~6.0 km·h-1; jogging: ~10.8 km·h-1; running: ~15.0 km·h-1). The amax was 6.01 ± 0.55 from a standing start, 4.33 ± 0.40 from trotting, 3.20 ± 0.49 from jogging and 2.29 ± 0.34 m·s-2 from running. The amax correlated significantly with vinit (r = -0.98) and the linear regression equation of highly-trained junior soccer players was: amax = -0.23 * vinit + 5.99. Using linear regression analysis, we propose to classify high-intensity actions as accelerations >75% of the amax, corresponding to acceleration values for our population of >4.51 initiated from standing, >3.25 from trotting, >2.40 from jogging, and >1.72 m·s-2 from running. The use of percentage acceleration avoids the bias of underestimating actions with high and overestimating actions with low initial running speed. Furthermore, percentage acceleration allows determining individual intensity thresholds that are specific for one population or one single player.

Technology needs for high-speed rotorcraft

NASA Technical Reports Server (NTRS)

Rutherford, John; Orourke, Matthew; Martin, Christopher; Lovenguth, Marc; Mitchell, Clark

1991-01-01

A study to determine the technology development required for high-speed rotorcraft development was conducted. The study begins with an initial assessment of six concepts capable of flight at, or greater than 450 knots with helicopter-like hover efficiency (disk loading less than 50 pfs). These concepts were sized and evaluated based on measures of effectiveness and operational considerations. Additionally, an initial assessment of the impact of technology advances on the vehicles attributes was made. From these initial concepts a tilt wing and rotor/wing concepts were selected for further evaluation. A more detailed examination of conversion and technology trade studies were conducted on these two vehicles, each sized for a different mission.

Unshrouded Centrifugal Turbopump Impeller Design Methodology

NASA Technical Reports Server (NTRS)

Prueger, George H.; Williams, Morgan; Chen, Wei-Chung; Paris, John; Williams, Robert; Stewart, Eric

2001-01-01

Turbopump weight continues to be a dominant parameter in the trade space for reduction of engine weight. Space Shuttle Main Engine weight distribution indicates that the turbomachinery make up approximately 30% of the total engine weight. Weight reduction can be achieved through the reduction of envelope of the turbopump. Reduction in envelope relates to an increase in turbopump speed and an increase in impeller head coefficient. Speed can be increased until suction performance limits are achieved on the pump or due to alternate constraints the turbine or bearings limit speed. Once the speed of the turbopump is set the impeller tip speed sets the minimum head coefficient of the machine. To reduce impeller diameter the head coefficient must be increased. A significant limitation with increasing head coefficient is that the slope of the head-flow characteristic is affected and this can limit engine throttling range. Unshrouded impellers offer a design option for increased turbopump speed without increasing the impeller head coefficient. However, there are several issues with regard to using an unshrouded impeller: there is a pump performance penalty due to the front open face recirculation flow, there is a potential pump axial thrust problem from the unbalanced front open face and the back shroud face, and since test data is very limited for this configuration, there is uncertainty in the magnitude and phase of the rotordynamic forces due to the front impeller passage. The purpose of the paper is to discuss the design of an unshrouded impeller and to examine the hydrodynamic performance, axial thrust, and rotordynamic performance. The design methodology will also be discussed. This work will help provide some guidelines for unshrouded impeller design.

Prediction of aerodynamic tonal noise from open rotors

NASA Astrophysics Data System (ADS)

Sharma, Anupam; Chen, Hsuan-nien

2013-08-01

A numerical approach for predicting tonal aerodynamic noise from "open rotors" is presented. "Open rotor" refers to an engine architecture with a pair of counter-rotating propellers. Typical noise spectra from an open rotor consist of dominant tones, which arise due to both the steady loading/thickness and the aerodynamic interaction between the two bladerows. The proposed prediction approach utilizes Reynolds Averaged Navier-Stokes (RANS) Computational Fluid Dynamics (CFD) simulations to obtain near-field description of the noise sources. The near-to-far-field propagation is then carried out by solving the Ffowcs Williams-Hawkings equation. Since the interest of this paper is limited to tone noise, a linearized, frequency domain approach is adopted to solve the wake/vortex-blade interaction problem.This paper focuses primarily on the speed scaling of the aerodynamic tonal noise from open rotors. Even though there is no theoretical mode cut-off due to the absence of nacelle in open rotors, the far-field noise is a strong function of the azimuthal mode order. While the steady loading/thickness noise has circumferential modes of high order, due to the relatively large number of blades (≈10-12), the interaction noise typically has modes of small orders. The high mode orders have very low radiation efficiency and exhibit very strong scaling with Mach number, while the low mode orders show a relatively weaker scaling. The prediction approach is able to capture the speed scaling (observed in experiment) of the overall aerodynamic noise very well.

Investigation of the Stability and Control Characteristics of a 1/20-Scale Model of the Consolidated Vultee XB-53 Airplane in the Langley Free-Flight Tunnel

NASA Technical Reports Server (NTRS)

Bennett, Charles V.

1947-01-01

An investigation of the low-speed, power-off stability and control characteristics of a 1/20-scale model of the Consolidated Vultee XB-53 airplane has been conducted in the Langley free-flight tunnel. In the investigation it was found that with flaps neutral satisfactory flight behavior at low speeds was obtainable with an increase in height of the vertical tail and with the inboard slats opened. In the flap-down slat-open condition the longitudinal stability was satisfactory, but it was impossible to obtain satisfactory lateral-flight characteristics even with the increase in height of the vertical tail because of the negative effective dihedral, low directional stability, and large-adverse yawing moments of the ailerons.

ChiMS: Open-source instrument control software platform on LabVIEW for imaging/depth profiling mass spectrometers.

PubMed

Cui, Yang; Hanley, Luke

2015-06-01

ChiMS is an open-source data acquisition and control software program written within LabVIEW for high speed imaging and depth profiling mass spectrometers. ChiMS can also transfer large datasets from a digitizer to computer memory at high repetition rate, save data to hard disk at high throughput, and perform high speed data processing. The data acquisition mode generally simulates a digital oscilloscope, but with peripheral devices integrated for control as well as advanced data sorting and processing capabilities. Customized user-designed experiments can be easily written based on several included templates. ChiMS is additionally well suited to non-laser based mass spectrometers imaging and various other experiments in laser physics, physical chemistry, and surface science.

ChiMS: Open-source instrument control software platform on LabVIEW for imaging/depth profiling mass spectrometers

PubMed Central

Cui, Yang; Hanley, Luke

2015-01-01

ChiMS is an open-source data acquisition and control software program written within LabVIEW for high speed imaging and depth profiling mass spectrometers. ChiMS can also transfer large datasets from a digitizer to computer memory at high repetition rate, save data to hard disk at high throughput, and perform high speed data processing. The data acquisition mode generally simulates a digital oscilloscope, but with peripheral devices integrated for control as well as advanced data sorting and processing capabilities. Customized user-designed experiments can be easily written based on several included templates. ChiMS is additionally well suited to non-laser based mass spectrometers imaging and various other experiments in laser physics, physical chemistry, and surface science. PMID:26133872

ChiMS: Open-source instrument control software platform on LabVIEW for imaging/depth profiling mass spectrometers

NASA Astrophysics Data System (ADS)

Cui, Yang; Hanley, Luke

2015-06-01

ChiMS is an open-source data acquisition and control software program written within LabVIEW for high speed imaging and depth profiling mass spectrometers. ChiMS can also transfer large datasets from a digitizer to computer memory at high repetition rate, save data to hard disk at high throughput, and perform high speed data processing. The data acquisition mode generally simulates a digital oscilloscope, but with peripheral devices integrated for control as well as advanced data sorting and processing capabilities. Customized user-designed experiments can be easily written based on several included templates. ChiMS is additionally well suited to non-laser based mass spectrometers imaging and various other experiments in laser physics, physical chemistry, and surface science.

The 2012 July 23 Backside Eruption: An Extreme Energetic Particle Event?

NASA Technical Reports Server (NTRS)

Gopalswamy, N.; Yashiro, S.; Thakur, N.; Makela, P.; Xie, H.; Akiyama, S.

2016-01-01

The backside coronal mass ejection (CME) of 2012 July 23 had a short Sun-to-Earth shock transit time (18.5 hr).The associated solar energetic particle (SEP) event had a greater than 10 MeV proton flux peaking at approximately 5000 pfu, and the energetic storm particle event was an order of magnitude larger, making it the most intense event in the space era at these energies. By a detailed analysis of the CME, shock, and SEP characteristics, we find that the July 23 event is consistent with a high-energy SEP event (accelerating particles to giga-electron volt energies). The times of maximum and fluence spectra in the range 10100 MeV were very hard, similar to those of ground-level enhancement (GLE) events. We found a hierarchical relationship between the CME initial speeds and the fluence spectral indices: CMEs with low initial speeds had SEP events with the softest spectra, while those with the highest initial speeds had SEP events with the hardest spectra. CMEs attaining intermediate speeds result in moderately hard spectra. The July 23 event was in the group of hard-spectrum events. During the July 23 event, the shock speed greater than (2000 km s(exp -1), the initial acceleration (approximately 1.70 km s(exp -2), and the shock-formation height (approximately 1.5 solar radii)were all typical of GLE events. The associated type II burst had emission components from meter to kilometer wavelengths, suggesting a strong shock. These observations confirm that the 2012 July 23 event is likely to be an extreme event in terms of the energetic particles it accelerated.

THE 2012 JULY 23 BACKSIDE ERUPTION: AN EXTREME ENERGETIC PARTICLE EVENT?

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

Gopalswamy, N.; Yashiro, S.; Thakur, N.

The backside coronal mass ejection (CME) of 2012 July 23 had a short Sun-to-Earth shock transit time (18.5 hr). The associated solar energetic particle (SEP) event had a >10 MeV proton flux peaking at ∼5000 pfu, and the energetic storm particle event was an order of magnitude larger, making it the most intense event in the space era at these energies. By a detailed analysis of the CME, shock, and SEP characteristics, we find that the July 23 event is consistent with a high-energy SEP event (accelerating particles to gigaelectronvolt energies). The times of maximum and fluence spectra in the rangemore » 10–100 MeV were very hard, similar to those of ground-level enhancement (GLE) events. We found a hierarchical relationship between the CME initial speeds and the fluence spectral indices: CMEs with low initial speeds had SEP events with the softest spectra, while those with the highest initial speeds had SEP events with the hardest spectra. CMEs attaining intermediate speeds result in moderately hard spectra. The July 23 event was in the group of hard-spectrum events. During the July 23 event, the shock speed (>2000 km s{sup −1}), the initial acceleration (∼1.70 km s{sup −2}), and the shock-formation height (∼1.5 solar radii) were all typical of GLE events. The associated type II burst had emission components from meter to kilometer wavelengths, suggesting a strong shock. These observations confirm that the 2012 July 23 event is likely to be an extreme event in terms of the energetic particles it accelerated.« less

The “voice” has it: screen reader adoption and switching behavior among vision impaired persons in India

PubMed Central

Pal, Joyojeet; Cutrell, Edward

2013-01-01

We present results from a mixed methods study of screen reader use and switching behavior among people with vision impairments in India. We examine loyalty and experimentation with screen readers and find that the main drivers of adoption for early users differ significantly from the factors that drive continued use by advanced users. We discuss the factor that emerges as one of the strongest stated drivers of early adoption, TTS “voice” quality, particularly a “human-sounding voice” as one of the key features differentiating free/open source (FOSS) products from more expensive proprietary products. While the initial preferences are driven by voice quality, application support becomes more important over time as users speed up their sound settings and become more comfortable with the resultant non-human-sounding speech. We discuss these findings from two theoretical perspectives – first, through the application of the economics of behavior switching, and second, vis-à-vis novice and expert approaches toward new product adoption. We argue that these findings further our understanding of initial user comfort related to assistive technology adoption, and the impact of early technology choices on long-term technology switching behavior. PMID:24620705

Efficient computation of the phylogenetic likelihood function on multi-gene alignments and multi-core architectures.

PubMed

Stamatakis, Alexandros; Ott, Michael

2008-12-27

The continuous accumulation of sequence data, for example, due to novel wet-laboratory techniques such as pyrosequencing, coupled with the increasing popularity of multi-gene phylogenies and emerging multi-core processor architectures that face problems of cache congestion, poses new challenges with respect to the efficient computation of the phylogenetic maximum-likelihood (ML) function. Here, we propose two approaches that can significantly speed up likelihood computations that typically represent over 95 per cent of the computational effort conducted by current ML or Bayesian inference programs. Initially, we present a method and an appropriate data structure to efficiently compute the likelihood score on 'gappy' multi-gene alignments. By 'gappy' we denote sampling-induced gaps owing to missing sequences in individual genes (partitions), i.e. not real alignment gaps. A first proof-of-concept implementation in RAXML indicates that this approach can accelerate inferences on large and gappy alignments by approximately one order of magnitude. Moreover, we present insights and initial performance results on multi-core architectures obtained during the transition from an OpenMP-based to a Pthreads-based fine-grained parallelization of the ML function.

Chronodiagnostic acquisition of recovery speed of heart rate under bathing stress.

PubMed

Ishijima, M; Togawa, T

1999-11-01

Cycling on an ergometer is one effective means of measuring cardiovascular function while applying stress on the heart. Bathing in a hot water bath applies a low stress to the heart. The electrocardiograms of a healthy adult male (aged 35 at the start of study) were recorded while taking a hot water bath with no electrode attached to the body over a period of 2 years (376 days over a 762 day period). The recovery speed following the initial overshoot of the heart rate (HR) was observed. The bathtub was designed for the automatic acquisition of ECG data. Immediately after immersion in the tub, the HR reached a peak within 20 s and then exponentially decreased toward the lowest rate in the 120 s of bathing. The initial recovery speed of the HR from the stress of bathing had a specific rhythm in the subject. Spectrum analysis of the speed series indicated that slow recovery speed appeared in cyclic periods of approximately 1 year, 42 days and 17 days. The methodology may provide a chronodiagnostic index of an exercise test for cardiovascular function.

Creation of Reusable Open Textbooks: Insights from the Connexions Repository

ERIC Educational Resources Information Center

Rodriguez-Solano, Carlos; Sánchez-Alonso, Salvador; Sicilia, Miguel-Angel

2015-01-01

Open textbook initiatives have appeared as an alternative to traditional publishing. These initiatives for the production of alternatively copyrighted educational resources provide a way of sharing materials through the Web. While the open model of peer-produced materials enables the global reuse of textbooks, the combination of fragments to…

Ghana Open Data Initiative | Ghana Open Data Initiative

Science.gov Websites

Information Technology Agency (NITA) 2012-2016 government of Ghana. All right reserved. Agencies Search  Get Involved Finance Health Agriculture Energy Education Environment Local Government City Data Extractive Statistics Business Elections About Us Open Government FAQ Aid Data Sites Data

Effects of thickness on the aerodynamic characteristics of an initial low-speed family of airfoils for general aviation applications

NASA Technical Reports Server (NTRS)

Mcghee, R. J.; Beasley, W. D.

1976-01-01

Wind tunnel tests were conducted to determine the effects of airfoil thickness-ratio on the low speed aerodynamic characteristics of an initial family of airfoils. The results were compared with theoretical predictions obtained from a subsonic viscous method. The tests were conducted over a Mach number range from 0.10 to 0.28. Chord Reynolds numbers varied from about 2.0 x 1 million to 9.0 x 1 million.

Development of an Open Source, Air-Deployable Weather Station

NASA Astrophysics Data System (ADS)

Krejci, A.; Lopez Alcala, J. M.; Nelke, M.; Wagner, J.; Udell, C.; Higgins, C. W.; Selker, J. S.

2017-12-01

We created a packaged weather station intended to be deployed in the air on tethered systems. The device incorporates lightweight sensors and parts and runs for up to 24 hours off of lithium polymer batteries, allowing the entire package to be supported by a thin fiber. As the fiber does not provide a stable platform, additional data (pitch and roll) from typical weather parameters (e.g. temperature, pressure, humidity, wind speed, and wind direction) are determined using an embedded inertial motion unit. All designs are open sourced including electronics, CAD drawings, and descriptions of assembly and can be found on the OPEnS lab website at http://www.open-sensing.org/lowcost-weather-station/. The Openly Published Environmental Sensing Lab (OPEnS: Open-Sensing.org) expands the possibilities of scientific observation of our Earth, transforming the technology, methods, and culture by combining open-source development and cutting-edge technology. New OPEnS labs are now being established in India, France, Switzerland, the Netherlands, and Ghana.

NASA Low-Speed Centrifugal Compressor for Fundamental Research

NASA Technical Reports Server (NTRS)

Wood, J. R.; Adam, P. W.; Buggele, A. E.

1983-01-01

A centrifugal compressor facility being built by the NASA Lewis Research Center is described; its purpose is to obtain benchmark experimental data for internal flow code verification and modeling. The facility will be heavily instrumented with standard pressure and temperature probes and have provisions for flow visualization and laser Doppler velocimetry. The facility will accommodate rotational speeds to 2400 rpm and will be rated at pressures to 1.25 atm. The initial compressor stage for testing is geometrically and dynamically representative of modern high-performance stages with the exception of Mach number levels. Design exit tip speed for the initial stage is 500 ft/sec with a pressure ratio of 1.17. The rotor exit backsweep is 55 deg from radial.

Active Flow Control for High-Speed Weapon Release from a Bay

DTIC Science & Technology

2004-06-01

and supersonic microjets . Each of these control devices offers unique attributes for high-speed weapon release and was the subject of considerable...final HIFEX actuator is the supersonic microjet , a device developed at Florida A&M/Florida State University and described by [3]. Small (0.016-inch...effectiveness of the microjets is that they destroy the spanwise coherence of the instabilities generated in an open weapons bay. Figure 4 illustrates the

Magnetic suspension system for an Annular Momentum Control Device (AMCD)

NASA Technical Reports Server (NTRS)

1979-01-01

A technique to control a rim suspended in a magnetic field was developed. A complete system was developed, incorporating a support structure, magnetic actuators, a rim drive mechanism, an emergency fail-safe system, servo control system, and control electronics. Open loop and closed loop response of the system at zero speed and at 500 revolutions per minute (r/min) of the rim was obtained and analyzed. The rim was then dynamically balanced and a rim speed of 725 r/min was achieved. An analog simulation of the hardware was developed and tested with the actual control electronics connected to the analog computer. The system under development is stable at rim speeds below 700 r/min. Test results indicate that the rim under test is not rigid. The rim has a warp and a number of binding modes which prevented achievement of higher speeds. Further development efforts are required to achieve higher rim speeds.

The relationship between hippocampal EEG theta activity and locomotor behaviour in freely moving rats: effects of vigabatrin.

PubMed

Bouwman, B M; van Lier, H; Nitert, H E J; Drinkenburg, W H I M; Coenen, A M L; van Rijn, C M

2005-01-30

The relationship between hippocampal electroencephalogram (EEG) theta activity and locomotor speed in both spontaneous and forced walking conditions was studied in rats after vigabatrin injection (500 mg/kg i.p.). Vigabatrin increased the percentage of time that rats spent being immobile. During spontaneous walking in the open field, the speed of locomotion was increased by vigabatrin, while theta peak frequency was decreased. Vigabatrin also reduced the theta peak frequency during forced (speed controlled) walking. There was only a weak positive correlation (r=0.22) between theta peak frequency and locomotor speed for the saline condition. Furthermore, vigabatrin abolishes the weak relationship between speed of locomotion and theta peak frequency. Vigabatrin and saline did not differ in the slope of the regression line, but showed different offset points at the theta peak frequency axis. Thus, other factors than speed of locomotion seem to be involved in determination of the theta peak frequency.

Evaluation of non-freeway rumble strips - phase II.

DOT National Transportation Integrated Search

2015-03-01

MDOTs rumble strip program for two-lane high speed rural highways was initiated in 2008 and : continued through 2010. This program included implementation of centerline rumble strips (CLRS) : on nearly 5,400 miles of two-lane high speed roads that...

Multilevel Parallelization of AutoDock 4.2.

PubMed

Norgan, Andrew P; Coffman, Paul K; Kocher, Jean-Pierre A; Katzmann, David J; Sosa, Carlos P

2011-04-28

Virtual (computational) screening is an increasingly important tool for drug discovery. AutoDock is a popular open-source application for performing molecular docking, the prediction of ligand-receptor interactions. AutoDock is a serial application, though several previous efforts have parallelized various aspects of the program. In this paper, we report on a multi-level parallelization of AutoDock 4.2 (mpAD4). Using MPI and OpenMP, AutoDock 4.2 was parallelized for use on MPI-enabled systems and to multithread the execution of individual docking jobs. In addition, code was implemented to reduce input/output (I/O) traffic by reusing grid maps at each node from docking to docking. Performance of mpAD4 was examined on two multiprocessor computers. Using MPI with OpenMP multithreading, mpAD4 scales with near linearity on the multiprocessor systems tested. In situations where I/O is limiting, reuse of grid maps reduces both system I/O and overall screening time. Multithreading of AutoDock's Lamarkian Genetic Algorithm with OpenMP increases the speed of execution of individual docking jobs, and when combined with MPI parallelization can significantly reduce the execution time of virtual screens. This work is significant in that mpAD4 speeds the execution of certain molecular docking workloads and allows the user to optimize the degree of system-level (MPI) and node-level (OpenMP) parallelization to best fit both workloads and computational resources.

Aerodynamic Load Measurements and Opening Characteristics of Automatic Leading Edge Slats on a 45 deg Sweptback Wing at Transonic Speeds

NASA Technical Reports Server (NTRS)

Arabian, Donald D.; Runckel, Jack F.; Reid, Charles F, Jr.

1961-01-01

Measurements of the normal force and chord force were made on the slats of a sting-mounted wing-fuselage model through a Mach number range of 0.60 to 1.03 and at angles of attack from 0 to 20 deg at subsonic speeds and from 0 to 8 deg at Mach number 1.03. The 20-percent-chord tapered leading-edge slats extended from 25 to 95 percent of the semispan and consisted of five segments. The model wing had 45 deg sweep, an aspect ratio of 3.56, a taper ratio of 0.3, and NACA 64(06)AO07 airfoil sections. Slat forces and moments were determined for the slats in the almost-closed and open positions for spanwise extents of 35 to 95 percent and 46 to 95 percent of the semispan. The results of the investigation showed little change in the slat maximum force and moment coefficients with Mach number. The coefficients for the open and almost-closed slat positions had similar variations with angle of attack. The loads on the individual slat segments were found to increase toward the tip for moderate angles of attack and decrease toward the tip for high angles of attack. An analysis of the opening and closing characteristics of aerodynamically operated slats opening on a circular-arc path is included.

Wiretapping the Internet

NASA Astrophysics Data System (ADS)

Antonelli, Charles J.; Honeyman, Peter

2001-02-01

This paper describes the Advanced Packet Vault, a technology for creating such a record by collecting and securely storing all packets observed on a network, with a scalable architecture intended to support network speeds in excess of 100 Mbps. Encryption is used to preserve users' security and privacy, permitting selected traffic to be made available without revealing other traffic. The Vault implementation, based on Linux and OpenBSD, is open-source.

High-Speed Rolling of AZ31 Magnesium Alloy Having Different Initial Textures

NASA Astrophysics Data System (ADS)

Onuki, Yusuke; Hara, Kenichiro; Utsunomiya, Hiroshi; Szpunar, Jerzy A.

2015-02-01

It is known that magnesium alloys can be rolled up to a large thickness reduction and develop a unique texture when the rolling speed is high (>1000 m/min). In order to understand the texture formation mechanism during high-strain-rate deformation, high-speed rolling of AZ31 magnesium alloy samples having different initial textures was conducted. The main components of the textures after the rolling were the RD-split basal, which consisted of 10°-20° inclining basal poles from the normal direction toward the rolling direction of the sheet, regardless of the different initial textures. With preheating at 473 K, all the samples were rolled without cracking while all were cracked when preheating was not applied. The optical micrographs and EBSD measurements showed a significant amount of twins and the cracks that developed along the shear bands consisted with laminated twins. Based on the texture simulation using the visco-plastic self-consistent model, it is concluded that the rapid development of the RD-split basal component from the initial basal alignment along the transverse direction was attributable to the tension twinning, The effect of the initial texture on the crack formation can be explained by the activation of the twinning system.

Updated Assessment of an Open Rotor Airplane Using an Advanced Blade Design

NASA Technical Reports Server (NTRS)

Hendricks, Eric S.; Berton, Jeffrey J.; Haller, William J.; Tong, Michael T.; Guynn, Mark D.

2013-01-01

Application of open rotor propulsion systems (historically referred to as "advanced turboprops" or "propfans") to subsonic transport aircraft received significant attention and research in the 1970s and 1980s when fuel efficiency was the driving focus of aeronautical research. Recent volatility in fuel prices and concern for aviation's environmental impact have renewed interest in open rotor propulsion, and revived research by NASA and a number of engine manufacturers. Over the last few years, NASA has revived and developed analysis capabilities to assess aircraft designs with open rotor propulsion systems. These efforts have been described in several previous papers along with initial results from applying these capabilities. The initial results indicated that open rotor engines have the potential to provide large reductions in fuel consumption and emissions. Initial noise analysis indicated that current noise regulations can be met with modern baseline blade designs. Improved blades incorporating low-noise features are expected to result in even lower noise levels. This paper describes improvements to the initial assessment, plus a follow-on study using a more advanced open rotor blade design to power the advanced singleaisle transport. The predicted performance and environmental results of these two advanced open rotor concepts are presented and compared.

Activating and Relaxing Music Entrains the Speed of Beat Synchronized Walking

PubMed Central

Leman, Marc; Moelants, Dirk; Varewyck, Matthias; Styns, Frederik; van Noorden, Leon; Martens, Jean-Pierre

2013-01-01

Inspired by a theory of embodied music cognition, we investigate whether music can entrain the speed of beat synchronized walking. If human walking is in synchrony with the beat and all musical stimuli have the same duration and the same tempo, then differences in walking speed can only be the result of music-induced differences in stride length, thus reflecting the vigor or physical strength of the movement. Participants walked in an open field in synchrony with the beat of 52 different musical stimuli all having a tempo of 130 beats per minute and a meter of 4 beats. The walking speed was measured as the walked distance during a time interval of 30 seconds. The results reveal that some music is ‘activating’ in the sense that it increases the speed, and some music is ‘relaxing’ in the sense that it decreases the speed, compared to the spontaneous walked speed in response to metronome stimuli. Participants are consistent in their observation of qualitative differences between the relaxing and activating musical stimuli. Using regression analysis, it was possible to set up a predictive model using only four sonic features that explain 60% of the variance. The sonic features capture variation in loudness and pitch patterns at periods of three, four and six beats, suggesting that expressive patterns in music are responsible for the effect. The mechanism may be attributed to an attentional shift, a subliminal audio-motor entrainment mechanism, or an arousal effect, but further study is needed to figure this out. Overall, the study supports the hypothesis that recurrent patterns of fluctuation affecting the binary meter strength of the music may entrain the vigor of the movement. The study opens up new perspectives for understanding the relationship between entrainment and expressiveness, with the possibility to develop applications that can be used in domains such as sports and physical rehabilitation. PMID:23874469

Activating and relaxing music entrains the speed of beat synchronized walking.

PubMed

Leman, Marc; Moelants, Dirk; Varewyck, Matthias; Styns, Frederik; van Noorden, Leon; Martens, Jean-Pierre

2013-01-01

Inspired by a theory of embodied music cognition, we investigate whether music can entrain the speed of beat synchronized walking. If human walking is in synchrony with the beat and all musical stimuli have the same duration and the same tempo, then differences in walking speed can only be the result of music-induced differences in stride length, thus reflecting the vigor or physical strength of the movement. Participants walked in an open field in synchrony with the beat of 52 different musical stimuli all having a tempo of 130 beats per minute and a meter of 4 beats. The walking speed was measured as the walked distance during a time interval of 30 seconds. The results reveal that some music is 'activating' in the sense that it increases the speed, and some music is 'relaxing' in the sense that it decreases the speed, compared to the spontaneous walked speed in response to metronome stimuli. Participants are consistent in their observation of qualitative differences between the relaxing and activating musical stimuli. Using regression analysis, it was possible to set up a predictive model using only four sonic features that explain 60% of the variance. The sonic features capture variation in loudness and pitch patterns at periods of three, four and six beats, suggesting that expressive patterns in music are responsible for the effect. The mechanism may be attributed to an attentional shift, a subliminal audio-motor entrainment mechanism, or an arousal effect, but further study is needed to figure this out. Overall, the study supports the hypothesis that recurrent patterns of fluctuation affecting the binary meter strength of the music may entrain the vigor of the movement. The study opens up new perspectives for understanding the relationship between entrainment and expressiveness, with the possibility to develop applications that can be used in domains such as sports and physical rehabilitation.

Effect of operational factors on bioregeneration of binary phenol and 4-chlorophenol-loaded granular activated carbon using PVA-immobilized biomass cryogels.

PubMed

Leong, Kwok-Yii; Adnan, Rohana; Lim, Poh-Eng; Ng, Si-Ling; Seng, Chye-Eng

2017-09-01

The effects of dry biomass density in cryogel beads, shaking speed and initial concentration ratio of phenol to 4-chlorophenol (4-CP) on the bioregeneration efficiencies of binary phenol and 4-CP-loaded granular activated carbon (GAC) for phenol and 4-CP, respectively, were investigated under the simultaneous adsorption and biodegradation approach. The results revealed higher bioregeneration efficiencies of binary-loaded GAC for phenol and 4-CP at higher dry biomass density but moderate shaking speed. The optimum dry biomass density in cryogel beads and shaking speed for use in bioregeneration were found to be 0.01 g/mL and 250 rpm, respectively. With respect to the initial phenol to 4-CP concentration ratio, the bioregeneration efficiencies were lower under increasing phenol and 4-CP initial concentrations, respectively, with the effect being more conspicuous under increasing 4-CP concentration. Higher bioregeneration efficiencies were achieved with the use of immobilized rather than suspended biomasses.

QuantumOptics.jl: A Julia framework for simulating open quantum systems

NASA Astrophysics Data System (ADS)

Krämer, Sebastian; Plankensteiner, David; Ostermann, Laurin; Ritsch, Helmut

2018-06-01

We present an open source computational framework geared towards the efficient numerical investigation of open quantum systems written in the Julia programming language. Built exclusively in Julia and based on standard quantum optics notation, the toolbox offers speed comparable to low-level statically typed languages, without compromising on the accessibility and code readability found in dynamic languages. After introducing the framework, we highlight its features and showcase implementations of generic quantum models. Finally, we compare its usability and performance to two well-established and widely used numerical quantum libraries.

Joint reconstruction of the initial pressure and speed of sound distributions from combined photoacoustic and ultrasound tomography measurements

NASA Astrophysics Data System (ADS)

Matthews, Thomas P.; Anastasio, Mark A.

2017-12-01

The initial pressure and speed of sound (SOS) distributions cannot both be stably recovered from photoacoustic computed tomography (PACT) measurements alone. Adjunct ultrasound computed tomography (USCT) measurements can be employed to estimate the SOS distribution. Under the conventional image reconstruction approach for combined PACT/USCT systems, the SOS is estimated from the USCT measurements alone and the initial pressure is estimated from the PACT measurements by use of the previously estimated SOS. This approach ignores the acoustic information in the PACT measurements and may require many USCT measurements to accurately reconstruct the SOS. In this work, a joint reconstruction method where the SOS and initial pressure distributions are simultaneously estimated from combined PACT/USCT measurements is proposed. This approach allows accurate estimation of both the initial pressure distribution and the SOS distribution while requiring few USCT measurements.

A one year pay-as-you-speed trial with economic incentives for not speeding.

PubMed

Stigson, Helena; Hagberg, Jan; Kullgren, Anders; Krafft, Maria

2014-01-01

The objective was to identify whether it was possible to change driver behavior by economic incentives and thereby reduce crash risk. Furthermore, the objective was to evaluate the participants' attitudes toward the pay-as-you-speed (PAYS) concept. A one-year PAYS trial with economic incentives for keeping speed limits using intelligent speed assistance (ISA) was conducted in Sweden during 2011-2012. The full incentive was a 30 percent discount off the insurance premium. The participants were private insurance customers and were randomized into a test group (initial n = 152, final n = 128) and a control group (initial n = 98, final n = 68). When driving, the drivers in the test group were informed and warned visually when the speed limit was exceeded. They could also follow their driving results on a personal website. The control group was not given any feedback at all. To reflect the impact of the PAYS concept the proportion of distance driven above the speed limit was compared between the 2 groups. The introduction of a PAYS concept shows that the test group significantly reduced the proportion of distance driven above the speed limit. The proportion of driving at a speed exceeding 5 km/h over the speed limit was 6 percent for the test group and 14 percent for the control group. It also showed that the effect was higher the higher the violation of speed. The result remained constant over time. It was shown that a PAYS concept is an effective way to reduce speed violations. Hence, it has the possibility to reduce crash severity and thereby to save lives. This could be an important step toward a safer road transport system. The majority of the participants were in favor of the concept, which indicates the potential of a new insurance product in the future.

Automated Cache Performance Analysis And Optimization

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

Mohror, Kathryn

While there is no lack of performance counter tools for coarse-grained measurement of cache activity, there is a critical lack of tools for relating data layout to cache behavior to application performance. Generally, any nontrivial optimizations are either not done at all, or are done ”by hand” requiring significant time and expertise. To the best of our knowledge no tool available to users measures the latency of memory reference instructions for partic- ular addresses and makes this information available to users in an easy-to-use and intuitive way. In this project, we worked to enable the Open|SpeedShop performance analysis tool tomore » gather memory reference latency information for specific instructions and memory ad- dresses, and to gather and display this information in an easy-to-use and intuitive way to aid performance analysts in identifying problematic data structures in their codes. This tool was primarily designed for use in the supercomputer domain as well as grid, cluster, cloud-based parallel e-commerce, and engineering systems and middleware. Ultimately, we envision a tool to automate optimization of application cache layout and utilization in the Open|SpeedShop performance analysis tool. To commercialize this soft- ware, we worked to develop core capabilities for gathering enhanced memory usage per- formance data from applications and create and apply novel methods for automatic data structure layout optimizations, tailoring the overall approach to support existing supercom- puter and cluster programming models and constraints. In this Phase I project, we focused on infrastructure necessary to gather performance data and present it in an intuitive way to users. With the advent of enhanced Precise Event-Based Sampling (PEBS) counters on recent Intel processor architectures and equivalent technology on AMD processors, we are now in a position to access memory reference information for particular addresses. Prior to the introduction of PEBS counters, cache behavior could only be measured reliably in the ag- gregate across tens or hundreds of thousands of instructions. With the newest iteration of PEBS technology, cache events can be tied to a tuple of instruction pointer, target address (for both loads and stores), memory hierarchy, and observed latency. With this information we can now begin asking questions regarding the efficiency of not only regions of code, but how these regions interact with particular data structures and how these interactions evolve over time. In the short term, this information will be vital for performance analysts understanding and optimizing the behavior of their codes for the memory hierarchy. In the future, we can begin to ask how data layouts might be changed to improve performance and, for a particular application, what the theoretical optimal performance might be. The overall benefit to be produced by this effort was a commercial quality easy-to- use and scalable performance tool that will allow both beginner and experienced parallel programmers to automatically tune their applications for optimal cache usage. Effective use of such a tool can literally save weeks of performance tuning effort. Easy to use. With the proposed innovations, finding and fixing memory performance issues would be more automated and hide most to all of the performance engineer exper- tise ”under the hood” of the Open|SpeedShop performance tool. One of the biggest public benefits from the proposed innovations is that it makes performance analysis more usable to a larger group of application developers. Intuitive reporting of results. The Open|SpeedShop performance analysis tool has a rich set of intuitive, yet detailed reports for presenting performance results to application developers. Our goal was to leverage this existing technology to present the results from our memory performance addition to Open|SpeedShop. Suitable for experts as well as novices. Application performance is getting more difficult to measure as the hardware platforms they run on become more complicated. This makes life difficult for the application developer, in that they need to know more about the hardware platform, including the memory system hierarchy, in order to understand the performance of their application. Some application developers are comfortable in that sce- nario, while others want to do their scientific research and not have to understand all the nuances in the hardware platform they are running their application on. Our proposed innovations were aimed to support both experts and novice performance analysts. Useful in many markets. The enhancement to Open|SpeedShop would appeal to a broader market space, as it will be useful in scientific, commercial, and cloud computing environments. Our goal was to use technology developed initially at the and Lawrence Livermore Na- tional Laboratory combined with the development and commercial software experience of the Argo Navis Technologies, LLC (ANT) to form a powerful combination to delivery these objectives.« less

Expectancy of an open-book test decreases performance on a delayed closed-book test.

PubMed

Agarwal, Pooja K; Roediger, Henry L

2011-11-01

Two experiments examined the influence of practice with, and the expectancy of, open-book tests (students viewed studied material while taking the test) versus closed-book tests (students completed the test without viewing the studied material) on delayed retention and transfer. Using GRE materials specifically designed for open-book testing, participants studied passages and then took initial open- or closed-book tests. Open-book testing led to better initial performance than closed-book testing, but on a delayed criterial (closed-book) test both types of testing produced similar retention after a two-day delay in Experiment 1. In Experiment 2 participants were informed in advance about the type of delayed criterial test to expect (open- or closed-book). Expecting an open-book test (relative to a closed-book test) decreased participants' time spent studying and their delayed test performance on closed-book comprehension and transfer tests, demonstrating that test expectancy can influence long-term learning. Expectancy of open-book tests may impair long-term retention and transfer compared to closed-book tests, despite superior initial performance on open-book tests and students' preference for open-book tests.

MetaDB a Data Processing Workflow in Untargeted MS-Based Metabolomics Experiments.

PubMed

Franceschi, Pietro; Mylonas, Roman; Shahaf, Nir; Scholz, Matthias; Arapitsas, Panagiotis; Masuero, Domenico; Weingart, Georg; Carlin, Silvia; Vrhovsek, Urska; Mattivi, Fulvio; Wehrens, Ron

2014-01-01

Due to their sensitivity and speed, mass-spectrometry based analytical technologies are widely used to in metabolomics to characterize biological phenomena. To address issues like metadata organization, quality assessment, data processing, data storage, and, finally, submission to public repositories, bioinformatic pipelines of a non-interactive nature are often employed, complementing the interactive software used for initial inspection and visualization of the data. These pipelines often are created as open-source software allowing the complete and exhaustive documentation of each step, ensuring the reproducibility of the analysis of extensive and often expensive experiments. In this paper, we will review the major steps which constitute such a data processing pipeline, discussing them in the context of an open-source software for untargeted MS-based metabolomics experiments recently developed at our institute. The software has been developed by integrating our metaMS R package with a user-friendly web-based application written in Grails. MetaMS takes care of data pre-processing and annotation, while the interface deals with the creation of the sample lists, the organization of the data storage, and the generation of survey plots for quality assessment. Experimental and biological metadata are stored in the ISA-Tab format making the proposed pipeline fully integrated with the Metabolights framework.

Jaw-phonatory coordination in chronic developmental stuttering.

PubMed

Loucks, Torrey M J; De Nil, Luc F; Sasisekaran, Jayanthi

2007-01-01

A deficiency in sensorimotor integration in a person who stutters may be a factor in the pathophysiology of developmental stuttering. To test oral sensorimotor function in adults who stutter, we used a task that requires the coordination of a jaw-opening movement with phonation onset. The task was adapted from previous limb coordination studies, which show that movement coordination depends on intact proprioception. We hypothesized that adult stutterers would show deficient jaw-phonatory coordination relative to control participants. The task required initiation of phonation as a jaw-opening movement passed through a narrow spatial target. Target amplitude and jaw movement speed were varied. The stuttering group showed significantly higher movement error and spatial variability in jaw-phonatory coordination compared to the control group, but group differences in movement velocity or duration were not found. The aberrant jaw-phonatory coordination of the stuttering participants suggests that stuttering is associated with an oral proprioceptive limitation, although, the findings are also consistent with a motor control deficit. As a result of this activity, reader will (1) learn about a hypothesis and evidence supporting the view that a sensorimotor deficit contributes to chronic developmental stuttering and (2) will obtain information about the role of proprioception in multi-articulatory coordination and how it can be tested using an oral-phonatory coordination task.

A Semi-analytic Criterion for the Spontaneous Initiation of Carbon Detonations in White Dwarfs

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

Garg, Uma; Chang, Philip, E-mail: umagarg@uwm.edu, E-mail: chang65@uwm.edu

Despite over 40 years of active research, the nature of the white dwarf progenitors of SNe Ia remains unclear. However, in the last decade, various progenitor scenarios have highlighted the need for detonations to be the primary mechanism by which these white dwarfs are consumed, but it is unclear how these detonations are triggered. In this paper we study how detonations are spontaneously initiated due to temperature inhomogeneities, e.g., hotspots, in burning nuclear fuel in a simplified physical scenario. Following the earlier work by Zel’Dovich, we describe the physics of detonation initiation in terms of the comparison between the spontaneousmore » wave speed and the Chapman–Jouguet speed. We develop an analytic expression for the spontaneous wave speed and utilize it to determine a semi-analytic criterion for the minimum size of a hotspot with a linear temperature gradient between a peak and base temperature for which detonations in burning carbon–oxygen material can occur. Our results suggest that spontaneous detonations may easily form under a diverse range of conditions, likely allowing a number of progenitor scenarios to initiate detonations that burn up the star.« less

A Semi-analytic Criterion for the Spontaneous Initiation of Carbon Detonations in White Dwarfs

NASA Astrophysics Data System (ADS)

Garg, Uma; Chang, Philip

2017-02-01

Despite over 40 years of active research, the nature of the white dwarf progenitors of SNe Ia remains unclear. However, in the last decade, various progenitor scenarios have highlighted the need for detonations to be the primary mechanism by which these white dwarfs are consumed, but it is unclear how these detonations are triggered. In this paper we study how detonations are spontaneously initiated due to temperature inhomogeneities, e.g., hotspots, in burning nuclear fuel in a simplified physical scenario. Following the earlier work by Zel’Dovich, we describe the physics of detonation initiation in terms of the comparison between the spontaneous wave speed and the Chapman-Jouguet speed. We develop an analytic expression for the spontaneous wave speed and utilize it to determine a semi-analytic criterion for the minimum size of a hotspot with a linear temperature gradient between a peak and base temperature for which detonations in burning carbon-oxygen material can occur. Our results suggest that spontaneous detonations may easily form under a diverse range of conditions, likely allowing a number of progenitor scenarios to initiate detonations that burn up the star.

The evolution of micro-cursoriality in mammals.

PubMed

Lovegrove, Barry G; Mowoe, Metobor O

2014-04-15

In this study we report on the evolution of micro-cursoriality, a unique case of cursoriality in mammals smaller than 1 kg. We obtained new running speed and limb morphology data for two species of elephant-shrews (Elephantulus spp., Macroscelidae) from Namaqualand, South Africa, which we compared with published data for other mammals. Elephantulus maximum running speeds were higher than those of most mammals smaller than 1 kg. Elephantulus also possess exceptionally high metatarsal:femur ratios (1.07) that are typically associated with fast unguligrade cursors. Cursoriality evolved in the Artiodactyla, Perissodactyla and Carnivora coincident with global cooling and the replacement of forests with open landscapes in the Oligocene and Miocene. The majority of mammal species, though, remained non-cursorial, plantigrade and small (<1 kg). The extraordinary running speed and digitigrady of elephant-shrews was established in the Early Eocene in the earliest macroscelid Prodiacodon, but was probably inherited from Paleocene, Holarctic stem macroscelids. Micro-cursoriality in macroscelids evolved from the plesiomorphic plantigrade foot of the possum-like ancestral mammal earlier than in other mammalian crown groups. Micro-cursoriality evolved first in forests, presumably in response to selection for rapid running speeds facilitated by local knowledge, in order to avoid predators. During the Miocene, micro-cursoriality was pre-adaptive to open, arid habitats, and became more derived in the newly evolved Elephantulus and Macroscelides elephant-shrews with trail running.

Ozone gradients in a spruce forest stand in relation to wind speed and time of the day

NASA Astrophysics Data System (ADS)

Pleijel, H.; Wallin, G.; Karlsson, P. E.; Skärby, L.

Ozone concentrations were measured outside and inside a 60-year-old 15-20 m tall spruce forest at a wind-exposed forest edge in southwest Sweden, at 3 and 13 m height 15 m outside the forest, and at 3 and 13 m height inside the forest 45 m from the forest edge. Measurements at 3 m were made with three replicate tubes on each site, the replicates being separated by 10 m. In addition, horizontal and vertical wind speeds were measured at 8 m height outside and inside the forest. During daytime, the concentrations inside the forest were generally slightly lower. Negative ozone concentration gradients from the open field into the forest were observed at 3 m height when the wind speed was below approximately 1.5 m s -1. At very low wind speeds, mainly occurring during the night, the ozone concentrations at 3 m height were frequently higher inside the forest than outside the forest. This may be caused by a very large aerodynamic resistance to ozone deposition, due to very small air movements inside the forest under stable conditions. It is concluded that ozone uptake by the trees is likely to be very small at night, even if stomata are not entirely closed. Results from open-top chamber experiments are also discussed.

SPINS-IND: Pellet injector for fuelling of magnetically confined fusion systems.

PubMed

Gangradey, R; Mishra, J; Mukherjee, S; Panchal, P; Nayak, P; Agarwal, J; Saxena, Y C

2017-06-01

Using a Gifford-McMahon cycle cryocooler based refrigeration system, a single barrel hydrogen pellet injection (SPINS-IND) system is indigenously developed at Institute for Plasma Research, India. The injector is based on a pipe gun concept, where a pellet formed in situ in the gun barrel is accelerated to high speed using high pressure light propellant gas. The pellet size is decided by considering the Greenwald density limit and its speed is decided by considering a neutral gas shielding model based scaling law. The pellet shape is cylindrical of dimension (1.6 mm ℓ × 1.8 mm φ). For pellet ejection and acceleration, a fast opening valve of short opening duration is installed at the breech of the barrel. A three-stage differential pumping system is used to restrict the flow of the propellant gas into the plasma vacuum vessel. Diagnostic systems such as light gate and fast imaging camera (240 000 frames/s) are employed to measure the pellet speed and size, respectively. A trigger circuit and a programmable logic controller based integrated control system developed on LabVIEW enables to control the pellet injector remotely. Using helium as a propellant gas, the pellet speed is varied in the range 650 m/s-800 m/s. The reliability of pellet formation and ejection is found to be more than 95%. This paper describes the details of SPINS-IND and its test results.

SPINS-IND: Pellet injector for fuelling of magnetically confined fusion systems

NASA Astrophysics Data System (ADS)

Gangradey, R.; Mishra, J.; Mukherjee, S.; Panchal, P.; Nayak, P.; Agarwal, J.; Saxena, Y. C.

2017-06-01

Using a Gifford-McMahon cycle cryocooler based refrigeration system, a single barrel hydrogen pellet injection (SPINS-IND) system is indigenously developed at Institute for Plasma Research, India. The injector is based on a pipe gun concept, where a pellet formed in situ in the gun barrel is accelerated to high speed using high pressure light propellant gas. The pellet size is decided by considering the Greenwald density limit and its speed is decided by considering a neutral gas shielding model based scaling law. The pellet shape is cylindrical of dimension (1.6 mm ℓ × 1.8 mm φ). For pellet ejection and acceleration, a fast opening valve of short opening duration is installed at the breech of the barrel. A three-stage differential pumping system is used to restrict the flow of the propellant gas into the plasma vacuum vessel. Diagnostic systems such as light gate and fast imaging camera (240 000 frames/s) are employed to measure the pellet speed and size, respectively. A trigger circuit and a programmable logic controller based integrated control system developed on LabVIEW enables to control the pellet injector remotely. Using helium as a propellant gas, the pellet speed is varied in the range 650 m/s-800 m/s. The reliability of pellet formation and ejection is found to be more than 95%. This paper describes the details of SPINS-IND and its test results.

Drag Coefficient and Foam in Hurricane Conditions.

NASA Astrophysics Data System (ADS)

Golbraikh, E.; Shtemler, Y.

2016-12-01

he present study is motivated by recent findings of saturation and even decrease in the drag coefficient (capping) in hurricane conditions, which is accompanied by the production of a foam layer on the ocean surface. As it is difficult to expect at present a comprehensive numerical modeling of the drag coefficient saturation that is followed by wave breaking and foam production, there is no complete confidence and understanding of the saturation phenomenon. Our semi-empirical model is proposed for the estimation of the foam impact on the variation of the effective drag coefficient, Cd , with the reference wind speed U10 in stormy and hurricane conditions. The proposed model treats the efficient air-sea aerodynamic roughness length as a sum of two weighted aerodynamic roughness lengths for the foam-free and foam-covered conditions. On the available optical and radiometric measurements of the fractional foam coverage,αf, combined with direct wind speed measurements in hurricane conditions, which provide the minimum of the effective drag coefficient, Cd for the sea covered with foam. The present model yields Cd10 versus U10 in fair agreement with that evaluated from both open-ocean and laboratory measurements of the vertical variation of mean wind speed in the range of U10 from low to hurricane speeds. The present approach opens opportunities for drag coefficient modeling in hurricane conditions and hurricane intensity estimation by the foam-coverage value using optical and radiometric measurements.

Preliminary results for mask metrology using spatial heterodyne interferometry

NASA Astrophysics Data System (ADS)

Bingham, Philip R.; Tobin, Kenneth; Bennett, Marylyn H.; Marmillion, Pat

2003-12-01

Spatial heterodyne interferometry (SHI) is an imaging technique that captures both the phase and amplitude of a complex wavefront in a single high-speed image. This technology was developed at the Oak Ridge National Laboratory (ORNL) and is currently being implemented for semiconductor wafer inspection by nLine Corporation. As with any system that measures phase, metrology and inspection of surface structures is possible by capturing a wavefront reflected from the surface. The interpretation of surface structure heights for metrology applications can become very difficult with the many layers of various materials used on semiconductor wafers, so inspection (defect detection) has been the primary focus for semiconductor wafers. However, masks used for photolithography typically only contain a couple well-defined materials opening the doors to high-speed mask metrology in 3 dimensions in addition to inspection. Phase shift masks often contain structures etched out of the transparent substrate material for phase shifting. While these structures are difficult to inspect using only intensity, the phase and amplitude images captured with SHI can produce very good resolution of these structures. The phase images also provide depth information that is crucial for these phase shift regions. Preliminary testing has been performed to determine the feasibility of SHI for high-speed non-contact mask metrology using a prototype SHI system with 532 nm wavelength illumination named the Visible Alpha Tool (VAT). These results show that prototype SHI system is capable of performing critical dimension measurements on 400nm lines with a repeatability of 1.4nm and line height measurements with a repeatability of 0.26nm. Additionally initial imaging of an alternating aperture phase shift mask has shown the ability of SHI to discriminate between typical phase shift heights.

Simultaneous Observations of a Large-scale Wave Event in the Solar Atmosphere: From Photosphere to Corona

NASA Astrophysics Data System (ADS)

Shen, Yuandeng; Liu, Yu

2012-06-01

For the first time, we report a large-scale wave that was observed simultaneously in the photosphere, chromosphere, transition region, and low corona layers of the solar atmosphere. Using the high temporal and high spatial resolution observations taken by the Solar Magnetic Activity Research Telescope at Hida Observatory and the Atmospheric Imaging Assembly (AIA) on board Solar Dynamic Observatory, we find that the wave evolved synchronously at different heights of the solar atmosphere, and it propagated at a speed of 605 km s-1 and showed a significant deceleration (-424 m s-2) in the extreme-ultraviolet (EUV) observations. During the initial stage, the wave speed in the EUV observations was 1000 km s-1, similar to those measured from the AIA 1700 Å (967 km s-1) and 1600 Å (893 km s-1) observations. The wave was reflected by a remote region with open fields, and a slower wave-like feature at a speed of 220 km s-1 was also identified following the primary fast wave. In addition, a type-II radio burst was observed to be associated with the wave. We conclude that this wave should be a fast magnetosonic shock wave, which was first driven by the associated coronal mass ejection and then propagated freely in the corona. As the shock wave propagated, its legs swept the solar surface and thereby resulted in the wave signatures observed in the lower layers of the solar atmosphere. The slower wave-like structure following the primary wave was probably caused by the reconfiguration of the low coronal magnetic fields, as predicted in the field-line stretching model.

CFD Simulation of Spread Risks of Infectious Disease due to Interactive Wind and Ventilation Airflows via Window Openings in High-Rise Buildings

NASA Astrophysics Data System (ADS)

Niu, J. L.; Gao, N. P.

2010-05-01

One of the concerns is that there may exist multiple infectious disease transmission routes across households in high-rise residential buildings, one of which is the natural ventilative airflow through open windows between flats, caused by buoyancy effects. This study presents the modeling of this cascade effect using computational fluid dynamics (CFD) technique. It is found that the presence of the pollutants generated in the lower floor is generally lower in the immediate upper floor by two orders of magnitude, but the risk of infection calculated by the Wells-Riley equation is only around one order of magnitude lower. It is found that, with single-side open-window conditions, wind blowing perpendicularly to the building may either reinforce or suppress the upward transport, depending on the wind speed. High-speed winds can restrain the convective transfer of heat and mass between flats, functioning like an air curtain. Despite the complexities of the air flow involved, it is clear that this transmission route should be taken into account in infection control.

The Langley 14- by 22-Foot Subsonic Tunnel: Description, Flow Characteristics, and Guide for Users

NASA Technical Reports Server (NTRS)

Gentry, Garl L., Jr.; Quinto, P. Frank; Gatlin, Gregory M.; Applin, Zachary T.

1990-01-01

The Langley 14- by 22-foot Subsonic Tunnel is a closed circuit, single-return atmospheric wind tunnel with a test section that can be operated in a variety of configurations (closed, slotted, partially open, and open). The closed test section configuration is 14.5 ft high by 21.75 ft wide and 50 ft long with a maximum speed of about 338 ft/sec. The open test section configuration has a maximum speed of about 270 ft/sec, and is formed by raising the ceiling and walls, to form a floor-only configuration. The tunnel may be configured with a moving-belt ground plane and a floor boundary-layer removal system at the entrance to the test section for ground effect testing. In addition, the tunnel had a two-component laser velocimeter, a frequency modulated (FM) tape system for dynamic data acquisition, flow visualization equipment, and acoustic testing capabilities. Users of the 14- by 22-foot Subsonic Tunnel are provided with information required for planning of experimental investigations including test hardware and model support systems.

Transcription initiation complex structures elucidate DNA opening.

PubMed

Plaschka, C; Hantsche, M; Dienemann, C; Burzinski, C; Plitzko, J; Cramer, P

2016-05-19

Transcription of eukaryotic protein-coding genes begins with assembly of the RNA polymerase (Pol) II initiation complex and promoter DNA opening. Here we report cryo-electron microscopy (cryo-EM) structures of yeast initiation complexes containing closed and open DNA at resolutions of 8.8 Å and 3.6 Å, respectively. DNA is positioned and retained over the Pol II cleft by a network of interactions between the TATA-box-binding protein TBP and transcription factors TFIIA, TFIIB, TFIIE, and TFIIF. DNA opening occurs around the tip of the Pol II clamp and the TFIIE 'extended winged helix' domain, and can occur in the absence of TFIIH. Loading of the DNA template strand into the active centre may be facilitated by movements of obstructing protein elements triggered by allosteric binding of the TFIIE 'E-ribbon' domain. The results suggest a unified model for transcription initiation with a key event, the trapping of open promoter DNA by extended protein-protein and protein-DNA contacts.

EFFICIENCY OPTIMIZATIN CONTROL OF AC INDUCTION MOTORS: INITIAL LABORATORY RESULTS

EPA Science Inventory

The report discusses the development of a fuzzy logic, energy-optimizing controller to improve the efficiency of motor/drive combinations that operate at varying loads and speeds. This energy optimizer is complemented by a sensorless speed controller that maintains motor shaft re...

Whole-field visual motion drives swimming in larval zebrafish via a stochastic process

PubMed Central

Portugues, Ruben; Haesemeyer, Martin; Blum, Mirella L.; Engert, Florian

2015-01-01

ABSTRACT Caudo-rostral whole-field visual motion elicits forward locomotion in many organisms, including larval zebrafish. Here, we investigate the dependence on the latency to initiate this forward swimming as a function of the speed of the visual motion. We show that latency is highly dependent on speed for slow speeds (<10 mm s−1) and then plateaus for higher values. Typical latencies are >1.5 s, which is much longer than neuronal transduction processes. What mechanisms underlie these long latencies? We propose two alternative, biologically inspired models that could account for this latency to initiate swimming: an integrate and fire model, which is history dependent, and a stochastic Poisson model, which has no history dependence. We use these models to predict the behavior of larvae when presented with whole-field motion of varying speed and find that the stochastic process shows better agreement with the experimental data. Finally, we discuss possible neuronal implementations of these models. PMID:25792753

Whole-field visual motion drives swimming in larval zebrafish via a stochastic process.

PubMed

Portugues, Ruben; Haesemeyer, Martin; Blum, Mirella L; Engert, Florian

2015-05-01

Caudo-rostral whole-field visual motion elicits forward locomotion in many organisms, including larval zebrafish. Here, we investigate the dependence on the latency to initiate this forward swimming as a function of the speed of the visual motion. We show that latency is highly dependent on speed for slow speeds (<10 mm s(-1)) and then plateaus for higher values. Typical latencies are >1.5 s, which is much longer than neuronal transduction processes. What mechanisms underlie these long latencies? We propose two alternative, biologically inspired models that could account for this latency to initiate swimming: an integrate and fire model, which is history dependent, and a stochastic Poisson model, which has no history dependence. We use these models to predict the behavior of larvae when presented with whole-field motion of varying speed and find that the stochastic process shows better agreement with the experimental data. Finally, we discuss possible neuronal implementations of these models. © 2015. Published by The Company of Biologists Ltd.

Linear dependence of surface expansion speed on initial plasma temperature in warm dense matter

DOE PAGES

Bang, Woosuk; Albright, Brian James; Bradley, Paul Andrew; ...

2016-07-12

Recent progress in laser-driven quasi-monoenergetic ion beams enabled the production of uniformly heated warm dense matter. Matter heated rapidly with this technique is under extreme temperatures and pressures, and promptly expands outward. While the expansion speed of an ideal plasma is known to have a square-root dependence on temperature, computer simulations presented here show a linear dependence of expansion speed on initial plasma temperature in the warm dense matter regime. The expansion of uniformly heated 1–100 eV solid density gold foils was modeled with the RAGE radiation-hydrodynamics code, and the average surface expansion speed was found to increase linearly withmore » temperature. The origin of this linear dependence is explained by comparing predictions from the SESAME equation-of-state tables with those from the ideal gas equation-of-state. In conclusion, these simulations offer useful insight into the expansion of warm dense matter and motivate the application of optical shadowgraphy for temperature measurement.« less

Influence of Wire Electrical Discharge Machining (WEDM) process parameters on surface roughness

NASA Astrophysics Data System (ADS)

Yeakub Ali, Mohammad; Banu, Asfana; Abu Bakar, Mazilah

2018-01-01

In obtaining the best quality of engineering components, the quality of machined parts surface plays an important role. It improves the fatigue strength, wear resistance, and corrosion of workpiece. This paper investigates the effects of wire electrical discharge machining (WEDM) process parameters on surface roughness of stainless steel using distilled water as dielectric fluid and brass wire as tool electrode. The parameters selected are voltage open, wire speed, wire tension, voltage gap, and off time. Empirical model was developed for the estimation of surface roughness. The analysis revealed that off time has a major influence on surface roughness. The optimum machining parameters for minimum surface roughness were found to be at a 10 V open voltage, 2.84 μs off time, 12 m/min wire speed, 6.3 N wire tension, and 54.91 V voltage gap.

Operating temperatures of open-rack installed photovoltaic inverters

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

Zhang, Z.; Wang, L.; Kurtz, S.

This paper presents a model for evaluating the heat-sink and component temperatures of open-rack installed photovoltaic inverters. These temperatures can be used for predicting inverter reliability. Inverter heat-sink temperatures were measured for inverters connected to three grid-connected PV (photovoltaic) test systems in Golden, Colorado, US. A model is proposed for calculating the inverter heat-sink temperature based on the ambient temperature, the ratio of the consumed power to the rated power of the inverter, and the measured wind speed. To verify and study this model, more than one year of inverter DC/AC power, irradiance, wind speed, and heat sink temperature risemore » data were collected and analyzed. The model is shown to be accurate in predicting average inverter temperatures, but will require further refinement for prediction of transient temperatures.« less

Falls in residential carpentry and drywall installation: findings from active injury surveillance with union carpenters.

PubMed

Lipscomb, Hester J; Dement, John M; Nolan, James; Patterson, Dennis; Li, Leiming; Cameron, Wilfred

2003-08-01

Active injury surveillance was conducted with a large, unionized workforce of residential and drywall carpenters over a 3-year period. Injured carpenters were interviewed by trained carpenter investigators and sites were visited where falls occurred. Qualitative information was collected on exposures, risk perception, training, and mentoring. Falls accounted for 20% of injuries. Same-level falls were often related to weather, carrying objects-sometimes with an obstructed view-housekeeping, terrain of the lot, and speed of work. Falls from height occurred from a variety of work surfaces and involved ladders, scaffolding, roofs, work on other unsecured surfaces, unprotected openings, speed, and weather conditions. Recognized fall protection strategies, such as guardrails, toe boards, tying off to appropriate anchors, and guarding openings, would have prevented many of these falls; these practices were not the norm on many sites.

17. VIEW SOUTHEAST OF 450 HP TURBINE IN BASEMENT OF ...

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

17. VIEW SOUTHEAST OF 450 HP TURBINE IN BASEMENT OF GRANITEVILLE MILL. THE MAIN BEARING OF THE TURBINE IS AT LEFT CENTER OF THE PHOTOGRAPH. A LOMBARD REGULATOR CAN BE SEEN AT THE LEFT CENTER REAR. THE LARGE HANDWHEEL AT THE LEFT CENTER IS GEARED TO A SECTIONAL GEAR AT THE CENTER OF THE PHOTOGRAPH AND IS USED TO MANUALLY OPEN THE GATES AND ALLOW WATER INTO THE TURBINE. THE SMALL PULLEY ON THE END OF THE MAIN SHAFT NORMALLY WOULD HAVE A BELT CONNECTING IT TO A PULLEY ON THE LOMBARD REGULATOR. THIS BELT TRANSMITTED TURBINE SPEED (RPM) TO THE LOMBARD WHICH WOULD OPEN OR CLOSE THE GATES TO KEEP TURBINE SPEED CONSTANT UNDER VARYING LOADS. THIS TURBINE WAS INSTALLED IN THE REFIT OF 1912. - Graniteville Mill, Marshall Street, Graniteville, Aiken County, SC

Far-Field Acoustic Power Level and Performance Analyses of F31/A31 Open Rotor Model at Simulated Scaled Takeoff, Nominal Takeoff, and Approach Conditions: Technical Report I

NASA Technical Reports Server (NTRS)

Sree, Dave

2015-01-01

Far-field acoustic power level and performance analyses of open rotor model F31/A31 have been performed to determine its noise characteristics at simulated scaled takeoff, nominal takeoff, and approach flight conditions. The nonproprietary parts of the data obtained from experiments in 9- by 15-Foot Low-Speed Wind Tunnel (9?15 LSWT) tests were provided by NASA Glenn Research Center to perform the analyses. The tone and broadband noise components have been separated from raw test data by using a new data analysis tool. Results in terms of sound pressure levels, acoustic power levels, and their variations with rotor speed, angle of attack, thrust, and input shaft power have been presented and discussed. The effect of an upstream pylon on the noise levels of the model has been addressed. Empirical equations relating model's acoustic power level, thrust, and input shaft power have been developed. The far-field acoustic efficiency of the model is also determined for various simulated flight conditions. It is intended that the results presented in this work will serve as a database for comparison and improvement of other open rotor blade designs and also for validating open rotor noise prediction codes.

Measurements of store forces and moments and cavity pressures for a generic store in and near a box cavity at subsonic and transonic speeds

NASA Technical Reports Server (NTRS)

Stallings, Robert L., Jr.; Plentovich, E. B.; Tracy, M. B.; Hemsch, Michael J.

1995-01-01

An experimental force and moment study was conducted in the Langley 8-Foot Transonic Pressure Tunnel for a generic store in and near rectangular box cavities contained in a flat-plate configuration at subsonic and transonic speeds. Surface pressures were measured inside the cavities and on the flat plate. The length-to-height ratios were 5.42, 6.25, 10.83, and 12.50. The corresponding width-to-height ratios were 2.00, 2.00, 4.00, and 4.00. The free-stream Mach number range was from 0.20 to 0.95. Surface pressure measurements inside the cavities indicated that the flow fields for the shallow cavities were either closed or transitional near the transitional/closed boundary. For the deep cavities, the flow fields were either open or near the open/transitional boundary. The presence of the store did not change the type of flow field and had only small effects on the pressure distributions. For transitional or open transitional flow fields, increasing the free-stream Mach number resulted in large reductions in pitching-moment coefficient. Values of pitching-moment coefficient were always much greater for closed flow fields than for open flow fields.

Long-Term Effects of an Extensive Cognitive Training on Personality Development.

PubMed

Sander, Julia; Schmiedek, Florian; Brose, Annette; Wagner, Gert G; Specht, Jule

2017-08-01

Previous research found that cognitive training increases the Big Five personality trait Openness to Experience during and some weeks after the intervention. The present study investigated whether long-term changes happen in Openness to Experience and other personality traits after an extensive cognitive training of memory and perceptual speed. The intervention group consisted of 204 adults (20-31 years and 65-80 years; 50% female) who received daily 1-hour cognitive training sessions for about 100 days. The control group consisted of 86 adults (21-29 years and 65-82 years; 51% female) who received no cognitive training. All participants answered the NEO Five-Factor Inventory before and 2 years after the cognitive training. Latent change models were applied that controlled for age group (young vs. old) and gender. In the long run, the cognitive training did not affect changes in any facet of Openness to Experience. This was true for young and old participants as well as for men and women. Instead, the cognitive training lowered the general increase of Conscientiousness. Even an extensive cognitive training on memory and perceptual speed does not serve as a sufficient intervention for enduring changes in Openness to Experiences or one of its facets. © 2016 Wiley Periodicals, Inc.

Free and open-source automated 3-D microscope.

PubMed

Wijnen, Bas; Petersen, Emily E; Hunt, Emily J; Pearce, Joshua M

2016-11-01

Open-source technology not only has facilitated the expansion of the greater research community, but by lowering costs it has encouraged innovation and customizable design. The field of automated microscopy has continued to be a challenge in accessibility due the expense and inflexible, noninterchangeable stages. This paper presents a low-cost, open-source microscope 3-D stage. A RepRap 3-D printer was converted to an optical microscope equipped with a customized, 3-D printed holder for a USB microscope. Precision measurements were determined to have an average error of 10 μm at the maximum speed and 27 μm at the minimum recorded speed. Accuracy tests yielded an error of 0.15%. The machine is a true 3-D stage and thus able to operate with USB microscopes or conventional desktop microscopes. It is larger than all commercial alternatives, and is thus capable of high-depth images over unprecedented areas and complex geometries. The repeatability is below 2-D microscope stages, but testing shows that it is adequate for the majority of scientific applications. The open-source microscope stage costs less than 3-9% of the closest proprietary commercial stages. This extreme affordability vastly improves accessibility for 3-D microscopy throughout the world. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Stable plume rise in a shear layer.

PubMed

Overcamp, Thomas J

2007-03-01

Solutions are given for plume rise assuming a power-law wind speed profile in a stably stratified layer for point and finite sources with initial vertical momentum and buoyancy. For a constant wind speed, these solutions simplify to the conventional plume rise equations in a stable atmosphere. In a shear layer, the point of maximum rise occurs further downwind and is slightly lower compared with the plume rise with a constant wind speed equal to the wind speed at the top of the stack. If the predictions with shear are compared with predictions for an equivalent average wind speed over the depth of the plume, the plume rise with shear is higher than plume rise with an equivalent average wind speed.

NASA low-speed centrifugal compressor for fundamental research

NASA Technical Reports Server (NTRS)

Wood, J. R.; Adam, P. W.; Buggele, A. E.

1983-01-01

A new centrifugal compressor facility being built by the NASA Lewis Research Center is described; its purpose is to obtain 'benchmark' experimental data for internal flow code verification and modeling. The facility will be heavily instrumented with standard pressure and temperature probes and have provisions for flow visualization and laser Doppler velocimetry. The facility will accommodate rotational speeds to 2400 rpm and will be rated at pressures to 1.25 atm. The initial compressor stage for testing is geometrically and dynamically representative of modern high-performance stages with the exception of Mach number levels. Design exit tip speed for the initial stage is 500 ft/sec with a pressure ratio of 1.17. The rotor exit backsweep is 55 deg from radial. The facility is expected to be operational in the first half of 1985.

Gait speed is limited but improves over the course of acute care physical therapy.

PubMed

Braden, Heather J; Hilgenberg, Sean; Bohannon, Richard W; Ko, Man-Soo; Hasson, Scott

2012-01-01

Gait is a common focus of physical therapists' management of patients in acute care settings. Walking speed, the distance a patient covers per unit time, has been advocated as a "sixth vital sign." However, the feasibility of measuring walking speed and the degree to which walking speed is limited or improves over the course of therapy in the acute care setting are unclear. The purpose of this study of patients undergoing physical therapy during acute care hospitalization, therefore, was to determine whether walking speed can be measured in acute care and whether walking speed is limited and changes over the course of therapy. This was an observational cross-sectional study. Participants were 46 hospital inpatients, mean age 75.0 years (SD = 7.8), referred to physical therapy and able to walk at least 20 ft. Information regarding diagnosis, comorbidities, physical assistance, device use, body height, and weight was obtained. Speed was determined during initial and final physical therapy visits while patients walked at their self-selected speed over a marked course in a hospital corridor. Therapists reported that walking speed was clinically feasible, requiring inexpensive, available resources, 4 minutes' additional time, and simple calculations for documentation. Initial walking speed was a mean of 0.33 m/s (SD = 0.21; 95% confidence interval [CI]: 0.27-0.39), whereas final speed was 0.37 m/s (SD = 0.20; 95% CI: 0.31-0.43). The Wilcoxon test showed the increase in walking speed (0.04 m/s) to be significant (P = .005) over a mean therapy period of 2.0 days (SD = 1.4) and total hospitalization period of 5.5 days (SD = 3.6). The effect size and standardized response mean were 0.19 and 0.36, respectively. Minimal detectable change was 0.18 m/s. Walking speed is a feasible measure for patients admitted to an acute care hospital. It shows that patients walk slowly relative to community requirements but that their speed improves even over a short course of therapy.

Opening the door to innovation.

PubMed

Schuurman, Janine; Graus, Yvo F; Labrijn, Aran F; Ruuls, Sigrid; Parren, Paul W H I

2014-01-01

Open innovation is the new buzz, with initiatives popping up left and right. Here, we give a personal perspective on a very successful, knowledge-driven innovation initiated in an academia- industry alliance, which culminated in technology platforms that enable the generation of therapeutic antibodies with novel properties. To start, we provide a general background on open innovation in the drug development field.

[Effects of wind speed on drying processes of fuelbeds composed of Mongolian oak broad-leaves.

PubMed

Zhang, Li Bin; Sun, Ping; Jin, Sen

2016-11-18

Water desorption processes of fuel beds with Mongolian oak broad-leaves were observed under conditions with various wind speeds but nearly constant air temperature and humidity. The effects of wind speed on drying coefficients of fuel beds with various moisture contents were analyzed. Three phases of drying process, namely high initial moisture content (>75%) of phase 1, transition state of phase 2, and equilibrium phase III could be identified. During phase 1, water loss rate under higher wind speed was higher than that under lower wind speed. Water loss rate under higher wind speed was lower than that under lower wind speed during phase 2. During phase 3, water loss rates under different wind speeds were similar. The wind effects decreased with the decrease of fuel moisture. The drying coefficient of the Mongolian oak broad-leaves fuel beds was affected by wind speed and fuel bed compactness, and the interaction between these two factors. The coefficient increased with wind speed roughly in a monotonic cubic polynomial form.

The Open Source DataTurbine Initiative: Streaming Data Middleware for Environmental Observing Systems

NASA Technical Reports Server (NTRS)

Fountain T.; Tilak, S.; Shin, P.; Hubbard, P.; Freudinger, L.

2009-01-01

The Open Source DataTurbine Initiative is an international community of scientists and engineers sharing a common interest in real-time streaming data middleware and applications. The technology base of the OSDT Initiative is the DataTurbine open source middleware. Key applications of DataTurbine include coral reef monitoring, lake monitoring and limnology, biodiversity and animal tracking, structural health monitoring and earthquake engineering, airborne environmental monitoring, and environmental sustainability. DataTurbine software emerged as a commercial product in the 1990 s from collaborations between NASA and private industry. In October 2007, a grant from the USA National Science Foundation (NSF) Office of Cyberinfrastructure allowed us to transition DataTurbine from a proprietary software product into an open source software initiative. This paper describes the DataTurbine software and highlights key applications in environmental monitoring.

The successes and challenges of open-source biopharmaceutical innovation.

PubMed

Allarakhia, Minna

2014-05-01

Increasingly, open-source-based alliances seek to provide broad access to data, research-based tools, preclinical samples and downstream compounds. The challenge is how to create value from open-source biopharmaceutical innovation. This value creation may occur via transparency and usage of data across the biopharmaceutical value chain as stakeholders move dynamically between open source and open innovation. In this article, several examples are used to trace the evolution of biopharmaceutical open-source initiatives. The article specifically discusses the technological challenges associated with the integration and standardization of big data; the human capacity development challenges associated with skill development around big data usage; and the data-material access challenge associated with data and material access and usage rights, particularly as the boundary between open source and open innovation becomes more fluid. It is the author's opinion that the assessment of when and how value creation will occur, through open-source biopharmaceutical innovation, is paramount. The key is to determine the metrics of value creation and the necessary technological, educational and legal frameworks to support the downstream outcomes of now big data-based open-source initiatives. The continued focus on the early-stage value creation is not advisable. Instead, it would be more advisable to adopt an approach where stakeholders transform open-source initiatives into open-source discovery, crowdsourcing and open product development partnerships on the same platform.

The Open Water Data Initiative: Water information for a thirsty nation

USGS Publications Warehouse

Rea, Alan; Clark, Edward; Adams, Angela; Samuels, William B.

2015-01-01

Initial efforts of the Open Water Data Initiative have focused on three use cases covering flooding, drought, and contaminant spill response, with a goal of identifying critical water data resources and making them more accessible. Significant progress has been made in the past year, although much remains to be done.

Correlated observations of three triggered lightning flashes

NASA Technical Reports Server (NTRS)

Idone, V. P.; Orville, R. E.; Hubert, P.; Barret, L.; Eybert-Berard, A.

1984-01-01

Three triggered lightning flashes, initiated during the Thunderstorm Research International Program (1981) at Langmuir Laboratory, New Mexico, are examined on the basis of three-dimensional return stroke propagation speeds and peak currents. Nonlinear relationships result between return stroke propagation speed and stroke peak current for 56 strokes, and between return stroke propagation speed and dart leader propagation speed for 32 strokes. Calculated linear correlation coefficients include dart leader propagation speed and ensuing return stroke peak current (32 strokes; r = 0.84); and stroke peak current and interstroke interval (69 strokes; r = 0.57). Earlier natural lightning data do not concur with the weak positive correlation between dart leader propagation speed and interstroke interval. Therefore, application of triggered lightning results to natural lightning phenomena must be made with certain caveats. Mean values are included for the three-dimensional return stroke propagation speed and for the three-dimensional dart leader propagation speed.

Design, fabrication, and initial test of a fixture for reducing the natural frequency of the Mod-O wind turbine tower

NASA Technical Reports Server (NTRS)

Winemiller, J. R.; Sullivan, T. L.; Sizemore, R. L.; Yee, S. T.

1979-01-01

It was desired to observe the behavior of a two bladed wind turbine where the tower first bending natural frequency is less than twice the rotor speed. The system then passes through resonance when accelerating to operating speed. The frequency of the original Mod-O tower was reduced by placing it on a spring fixture. The fixture is adjustable to provide a range of tower bending frequencies. Fixture design details are given and behavior during initial operation is described.

Seed release by invasive thistles: the impact of plant and environmental factors

PubMed Central

Jongejans, Eelke; Pedatella, Nicholas M; Shea, Katriona; Skarpaas, Olav; Auhl, Richard

2007-01-01

Dispersal is a key process in biological studies of spatial dynamics, but the initiation of dispersal has often been neglected, despite strong indications that differential timing of dispersal can significantly affect dispersal distances. To investigate which plant and environmental factors determine the release of plumed seeds by the invasive thistles Carduus acanthoides and Carduus nutans, we exposed 192 flower heads of each species to increasing wind speeds in a full-factorial wind tunnel experiment with four air flow turbulence, three flower head wetness and two flower head temperature levels. The number of seed releases was highest under dry and turbulent conditions and from heads that had already lost a considerable number of seeds, but was not affected by flower head size, head angle or temperature. Inspection of the trials on video showed that higher wind speeds were needed to meet the seed release threshold in laminar flows and for C. acanthoides heads that had been wet for a longer time. Species differences were minimal, although seed release was more sensitive to lower levels of turbulence in the larger-headed and more open C. nutans heads. Knowledge of seed release biases towards weather conditions favourable for long-distance dispersal improves our understanding of the spread of invaders and allows managers to increase the efficiency of their containment strategies by applying them at crucial times. PMID:17666379

Mesoscopic structural phase progression in photo-excited VO 2 revealed by time-resolved x-ray diffraction microscopy

DOE PAGES

Zhu, Yi; Cai, Zhonghou; Chen, Pice; ...

2016-02-26

Dynamical phase separation during a solid-solid phase transition poses a challenge for understanding the fundamental processes in correlated materials. Critical information underlying a phase transition, such as localized phase competition, is difficult to reveal by measurements that are spatially averaged over many phase seperated regions. The ability to simultanousely track the spatial and temporal evolution of such systems is essential to understanding mesoscopic processes during a phase transition. Using state-of- the-art time-resolved hard x-ray diffraction microscopy, we directly visualize the structural phase progression in a VO 2 film upon photoexcitation. Following a homogenous in-plane optical excitation, the phase transformation ismore » initiated at discrete sites and completed by the growth of one lattice structure into the other, instead of a simultaneous isotropic lattice symmetry change. The time-dependent x-ray diffraction spatial maps show that the in-plane phase progression in laser-superheated VO 2 is via a displacive lattice transformation as a result of relaxation from an excited monoclinic phase into a rutile phase. The speed of the phase front progression is quantitatively measured, which is faster than the process driven by in-plane thermal diffusion but slower than the sound speed in VO 2. Lastly, the direct visualization of localized structural changes in the time domain opens a new avenue to study mesoscopic processes in driven systems.« less

Mesoscopic structural phase progression in photo-excited VO2 revealed by time-resolved x-ray diffraction microscopy

NASA Astrophysics Data System (ADS)

Zhu, Yi; Cai, Zhonghou; Chen, Pice; Zhang, Qingteng; Highland, Matthew J.; Jung, Il Woong; Walko, Donald A.; Dufresne, Eric M.; Jeong, Jaewoo; Samant, Mahesh G.; Parkin, Stuart S. P.; Freeland, John W.; Evans, Paul G.; Wen, Haidan

2016-02-01

Dynamical phase separation during a solid-solid phase transition poses a challenge for understanding the fundamental processes in correlated materials. Critical information underlying a phase transition, such as localized phase competition, is difficult to reveal by measurements that are spatially averaged over many phase separated regions. The ability to simultaneously track the spatial and temporal evolution of such systems is essential to understanding mesoscopic processes during a phase transition. Using state-of-the-art time-resolved hard x-ray diffraction microscopy, we directly visualize the structural phase progression in a VO2 film upon photoexcitation. Following a homogenous in-plane optical excitation, the phase transformation is initiated at discrete sites and completed by the growth of one lattice structure into the other, instead of a simultaneous isotropic lattice symmetry change. The time-dependent x-ray diffraction spatial maps show that the in-plane phase progression in laser-superheated VO2 is via a displacive lattice transformation as a result of relaxation from an excited monoclinic phase into a rutile phase. The speed of the phase front progression is quantitatively measured, and is faster than the process driven by in-plane thermal diffusion but slower than the sound speed in VO2. The direct visualization of localized structural changes in the time domain opens a new avenue to study mesoscopic processes in driven systems.

Mesoscopic structural phase progression in photo-excited VO2 revealed by time-resolved x-ray diffraction microscopy.

PubMed

Zhu, Yi; Cai, Zhonghou; Chen, Pice; Zhang, Qingteng; Highland, Matthew J; Jung, Il Woong; Walko, Donald A; Dufresne, Eric M; Jeong, Jaewoo; Samant, Mahesh G; Parkin, Stuart S P; Freeland, John W; Evans, Paul G; Wen, Haidan

2016-02-26

Dynamical phase separation during a solid-solid phase transition poses a challenge for understanding the fundamental processes in correlated materials. Critical information underlying a phase transition, such as localized phase competition, is difficult to reveal by measurements that are spatially averaged over many phase separated regions. The ability to simultaneously track the spatial and temporal evolution of such systems is essential to understanding mesoscopic processes during a phase transition. Using state-of-the-art time-resolved hard x-ray diffraction microscopy, we directly visualize the structural phase progression in a VO2 film upon photoexcitation. Following a homogenous in-plane optical excitation, the phase transformation is initiated at discrete sites and completed by the growth of one lattice structure into the other, instead of a simultaneous isotropic lattice symmetry change. The time-dependent x-ray diffraction spatial maps show that the in-plane phase progression in laser-superheated VO2 is via a displacive lattice transformation as a result of relaxation from an excited monoclinic phase into a rutile phase. The speed of the phase front progression is quantitatively measured, and is faster than the process driven by in-plane thermal diffusion but slower than the sound speed in VO2. The direct visualization of localized structural changes in the time domain opens a new avenue to study mesoscopic processes in driven systems.

Open Energy Info (OpenEI) (Fact Sheet)

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

Not Available

2010-12-01

The Open Energy Information (OpenEI.org) initiative is a free, open-source, knowledge-sharing platform. OpenEI was created to provide access to data, models, tools, and information that accelerate the transition to clean energy systems through informed decisions.

Initial correlations in open-systems dynamics: The Jaynes-Cummings model

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

Smirne, Andrea; Vacchini, Bassano; INFN, Sezione di Milano, Via Celoria 16, I-20133 Milano

2010-12-15

Employing the trace distance as a measure for the distinguishability of quantum states, we study the influence of initial correlations on the dynamics of open systems. We concentrate on the Jaynes-Cummings model for which the knowledge of the exact joint dynamics of system and reservoir allows the treatment of initial states with arbitrary correlations. As a measure for the correlations in the initial state we consider the trace distance between the system-environment state and the product of its marginal states. In particular, we examine the correlations contained in the thermal equilibrium state for the total system, analyze their dependence onmore » the temperature and on the coupling strength, and demonstrate their connection to the entanglement properties of the eigenstates of the Hamiltonian. A detailed study of the time dependence of the distinguishability of the open system states evolving from the thermal equilibrium state and its corresponding uncorrelated product state shows that the open system dynamically uncovers typical features of the initial correlations.« less

Adjustments with running speed reveal neuromuscular adaptations during landing associated with high mileage running training.

PubMed

Verheul, Jasper; Clansey, Adam C; Lake, Mark J

2017-03-01

It remains to be determined whether running training influences the amplitude of lower limb muscle activations before and during the first half of stance and whether such changes are associated with joint stiffness regulation and usage of stored energy from tendons. Therefore, the aim of this study was to investigate neuromuscular and movement adaptations before and during landing in response to running training across a range of speeds. Two groups of high mileage (HM; >45 km/wk, n = 13) and low mileage (LM; <15 km/wk, n = 13) runners ran at four speeds (2.5-5.5 m/s) while lower limb mechanics and electromyography of the thigh muscles were collected. There were few differences in prelanding activation levels, but HM runners displayed lower activations of the rectus femoris, vastus medialis, and semitendinosus muscles postlanding, and these differences increased with running speed. HM runners also demonstrated higher initial knee stiffness during the impact phase compared with LM runners, which was associated with an earlier peak knee flexion velocity, and both were relatively unchanged by running speed. In contrast, LM runners had higher knee stiffness during the slightly later weight acceptance phase and the disparity was amplified with increases in speed. It was concluded that initial knee joint stiffness might predominantly be governed by tendon stiffness rather than muscular activations before landing. Estimated elastic work about the ankle was found to be higher in the HM runners, which might play a role in reducing weight acceptance phase muscle activation levels and improve muscle activation efficiency with running training. NEW & NOTEWORTHY Although neuromuscular factors play a key role during running, the influence of high mileage training on neuromuscular function has been poorly studied, especially in relation to running speed. This study is the first to demonstrate changes in neuromuscular conditioning with high mileage training, mainly characterized by lower thigh muscle activation after touch down, higher initial knee stiffness, and greater estimates of energy return, with adaptations being increasingly evident at faster running speeds. Copyright © 2017 the American Physiological Society.

Transformational leadership, initiating structure, and substitutes for leadership: a longitudinal study of research and development project team performance.

PubMed

Keller, Robert T

2006-01-01

Transformational leadership, initiating structure, and selected substitutes for leadership were studied as longitudinal predictors of performance in 118 research and development (R&D) project teams from 5 firms. As hypothesized, transformational leadership predicted 1-year-later technical quality, schedule performance, and cost performance and 5-year-later profitability and speed to market. Initiating structure predicted all the performance measures. The substitutes of subordinate ability and an intrinsically satisfying task each predicted technical quality and profitability, and ability predicted speed to market. Moderator effects for type of R&D work were hypothesized and found whereby transformational leadership was a stronger predictor of technical quality in research projects, whereas initiating structure was a stronger predictor of technical quality in development projects. Implications for leadership theory and research are discussed. (c) 2006 APA, all rights reserved.

Transient flow characteristics of a high speed rotary valve

NASA Astrophysics Data System (ADS)

Browning, Patrick H.

Pressing economic and environmental concerns related to the performance of fossil fuel burning internal combustion engines have revitalized research in more efficient, cleaner burning combustion methods such as homogeneous charge compression ignition (HCCI). Although many variations of such engines now exist, several limiting factors have restrained the full potential of HCCI. A new method patented by West Virginia University (WVU) called Compression Ignition by Air Injection (CIBAI) may help broaden the range of effective HCCI operation. The CIBAI process is ideally facilitated by operating two synchronized piston-cylinders mounted head-to-head with one of the cylinders filled with a homogeneous mixture of air and fuel and the other cylinder filled with air. A specialized valve called the cylinder connecting valve (CCV) separates the two cylinders, opens just before reaching top dead center (TDC), and allows the injection air into the charge to achieve autoignition. The CCV remains open during the entire power stroke such that upon ignition the rapid pressure rise in the charge cylinder forces mass flow back through the CCV into the air-only cylinder. The limited mass transfer between the cylinders through the CCV limits the theoretical auto ignition timing capabilities and thermal efficiency of the CIBAI cycle. Research has been performed to: (1) Experimentally measure the transient behavior of a potential CCV design during valve opening between two chambers maintained at constant pressure and again at constant volume; (2) Develop a modified theoretical CCV mass flow model based upon the measured cold flow valve performance that is capable of predicting the operating conditions required for successful mixture autoignition; (3) Make recommendations for future CCV designs to maximize CIBAI combustion range. Results indicate that the modified-ball CCV design offers suitable transient flow qualities required for application to the CIBAI concept. Mass injection events were experimentally mapped as a function of valve speed, inter-cylinder pressure ratios and volume ratios and the results were compared to compressible flow theoretical models. Specifically, the transient behavior suggested a short-lived loss-mode initiation closely resembled by shock tube theory followed by a quasi-steady flow regime resembling choked flow behavior. An empirical model was then employed to determine the useful range of the CCV design as applied to a four-stroke CIBAI engine cycle modeled using a 1-D quasi-steady numerical method, with particular emphasis on the cyclic timing of the CCV opening. Finally, a brief discussion of a high-temperature version of the CCV design is presented.

Safety Relevant Observations on the X2000 Train as Developed for the Swedish National Railways

DOT National Transportation Integrated Search

1990-01-01

The safety of high speed rail technology proposed for possible application in the United States is of concern to the Federal Railroad Administration. This report, one in a series of reports planned for high speed rail technologies presents an initial...

The increased cost of ventral hernia recurrence: a cost analysis.

PubMed

Davila, D G; Parikh, N; Frelich, M J; Goldblatt, M I

2016-12-01

Over 300,000 ventral hernia repairs (VHRs) are performed each year in the US. We sought to assess the economic burden related to ventral hernia recurrences with a focused comparison of those with the initial open versus laparoscopic surgery. The Premier Alliance database from 2009 to 2014 was utilized to obtain patient demographics and comorbid indices, including the Charlson comorbidity index (CCI). Total hospital cost and resource expenses during index laparoscopic and open VHRs and subsequent recurrent repairs were also obtained. The sample was separated into laparoscopic and open repair groups from the initial operation. Adjusted and propensity score matched cost outcome data were then compared amongst groups. One thousand and seventy-seven patients were used for the analysis with a recurrence rate of 3.78 %. For the combined sample, costs were significantly higher during recurrent hernia repair hospitalization ($21,726 versus $19,484, p < 0.0001). However, for index laparoscopic repairs, both the adjusted total hospital cost and department level costs were similar during the index and the recurrent visit. The costs and resource utilization did not go up due to recurrence, even though these patients had greater severity during the recurrent visit (CCI score 0.92 versus 1.06; p = 0.0092). Using a matched sample, the total hospital recurrence cost was higher for the initial open group compared to laparoscopic group ($14,520 versus $12,649; p = 0.0454). Based on our analysis, need for recurrent VHR adds substantially to total hospital costs and resource utilization. Following initial laparoscopic repair, however, the total cost of recurrent repair is not significantly increased, as it is following initial open repair. When comparing the initial laparoscopic repair versus open, the cost of recurrence was higher for the prior open repair group.

Functional form for plasma velocity in a rapidly rotating tokamak discharge

DOE PAGES

Burrell, Keith H.; Chrystal, C. olin

2014-07-25

A recently developed technique using charge exchange spectroscopy determines the ion poloidal rotation in tokamak plasmas from the poloidal variation in the toroidal angular rotation speed. The basis for this technique is the functional form for the plasma velocity calculated from the equilibrium equations. The initial development of this technique utilized the functional form determined for conditions where the ion toroidal rotation speed is much smaller than the ion thermal speed. There are cases, however, where the toroidal rotation can be comparable to the ion thermal speed, especially for high atomic number impurities. Furthermore, the present paper extends the previousmore » analysis to this high rotation speed case and demonstrates how to extract the poloidal rotation speed from measurements of the toroidal angular rotation speed at two points on a flux surface.« less

Effects of reset stators and a rotating, grooved stator hub on performance of a 1.92-pressure-ratio compressor stage

NASA Technical Reports Server (NTRS)

Lewis, G. W., Jr.; Urasek, D. C.; Reid, L.

1977-01-01

The overall performance and blade-element performance of a transonic fan stage are presented for two modified test configurations and are compared with the unmodified stage. Tests were conducted with reset stators 2 deg open and reset stators with a rotating grooved stator hub. Detailed radial and circumferential (behind stator) surveys of the flow conditions were made over the stable operating range at rotative speeds of 70, 90, and 100 percent of design speed. Reset stator blade tests indicated a small increase in stage efficiency, pressure ratio, and maximum weight flow at each speed. Performance with reset stators and a rotating, grooved stator hub resulted in an additional increase in stage efficiency and pressure ratio at all speeds. The rotating grooved stator hub reduced hub losses considerably.

The Open Learning Initiative: Measuring the Effectiveness of the OLI Statistics Course in Accelerating Student Learning

ERIC Educational Resources Information Center

Lovett, Marsha; Meyer, Oded; Thille, Candace

2008-01-01

The Open Learning Initiative (OLI) is an open educational resources project at Carnegie Mellon University that began in 2002 with a grant from The William and Flora Hewlett Foundation. OLI creates web-based courses that are designed so that students can learn effectively without an instructor. In addition, the courses are often used by instructors…

Open Source Initiative Powers Real-Time Data Streams

NASA Technical Reports Server (NTRS)

2014-01-01

Under an SBIR contract with Dryden Flight Research Center, Creare Inc. developed a data collection tool called the Ring Buffered Network Bus. The technology has now been released under an open source license and is hosted by the Open Source DataTurbine Initiative. DataTurbine allows anyone to stream live data from sensors, labs, cameras, ocean buoys, cell phones, and more.

Slotted-wall research with disk and parachute models in a low-speed wind tunnel

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

Macha, J.M.; Buffington, R.J.; Henfling, J.L.

1990-01-01

An experimental investigation of slotted-wall blockage interference has been conducted using disk and parachute models in a low speed wind tunnel. Test section open area ratio, model geometric blockage ratio, and model location along the length of the test section were systematically varied. Resulting drag coefficients were compared to each other and to interference-free measurements obtained in a much larger wind tunnel where the geometric blockage ratio was less than 0.0025. 9 refs., 10 figs.

X-45A Air Vehicle #1 during flight #13, with weapons bay door open

NASA Image and Video Library

2003-02-21

The DARPA/U.S. Air Force X-45A Unmanned Combat Air Vehicle (UCAV) system demonstration program completed the first phase of demonstrations, known as Block I, on Feb. 28, 2003. The final Block I activities included two flights at Dryden, during which safe operation of the weapons bay door was verified at 35,000 feet and speeds of Mach 0.75, the maximum planned altitude and speed for the two X-45A demonstrator vehicles.

Double-reed exhaust valve engine

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

Bennett, Charles L.

An engine based on a reciprocating piston engine that extracts work from pressurized working fluid. The engine includes a double reed outlet valve for controlling the flow of low-pressure working fluid out of the engine. The double reed provides a stronger force resisting closure of the outlet valve than the force tending to open the outlet valve. The double reed valve enables engine operation at relatively higher torque and lower efficiency at low speed, with lower torque, but higher efficiency at high speed.

Experimental results concerning centrifugal impeller excitations

NASA Technical Reports Server (NTRS)

Vance, J. M.; Landadio, F. J.

1980-01-01

The effect of working fluid on the dynamics of an impeller with radial vanes was investigated. The impeller was supported vertically from a very flexible quill shaft in order to produce a low critical speed, and to allow the fluid dynamic effects on the impeller to predominate. The shaft was supported from ball bearings, so that there was no possibility of oil whip from fluid film bearings as a destabilizing influence. The impeller was run both in the atmosphere, and submerged in working fluids contained in a cylindrical housing, open at the top. Variable speed was obtained with a dc gearmotor drive unit. The speed was measured with a proximity probe pulse tachometer and electronic digital counter.

Exploring the potential of open big data from ticketing websites to characterize travel patterns within the Chinese high-speed rail system

PubMed Central

Luan, Xiali; Han, Shanrui; Zhou, Wen

2017-01-01

Big data have contributed to deepen our understanding in regards to many human systems, particularly human mobility patterns and the structure and functioning of transportation systems. Resonating the recent call for ‘open big data,’ big data from various sources on a range of scales have become increasingly accessible to the public. However, open big data relevant to travelers within public transit tools remain scarce, hindering any further in-depth study on human mobility patterns. Here, we explore ticketing-website derived data that are publically available but have been largely neglected. We demonstrate the power, potential and limitations of this open big data, using the Chinese high-speed rail (HSR) system as an example. Using an application programming interface, we automatically collected the data on the remaining tickets (RTD) for scheduled trains at the last second before departure in order to retrieve information on unused transit capacity, occupancy rate of trains, and passenger flux at stations. We show that this information is highly useful in characterizing the spatiotemporal patterns of traveling behaviors on the Chinese HSR, such as weekend traveling behavior, imbalanced commuting behavior, and station functionality. Our work facilitates the understanding of human traveling patterns along the Chinese HSR, and the functionality of the largest HSR system in the world. We expect our work to attract attention regarding this unique open big data source for the study of analogous transportation systems. PMID:28574991

Exploring the potential of open big data from ticketing websites to characterize travel patterns within the Chinese high-speed rail system.

PubMed

Wei, Sheng; Yuan, Jinfu; Qiu, Yanning; Luan, Xiali; Han, Shanrui; Zhou, Wen; Xu, Chi

2017-01-01

Big data have contributed to deepen our understanding in regards to many human systems, particularly human mobility patterns and the structure and functioning of transportation systems. Resonating the recent call for 'open big data,' big data from various sources on a range of scales have become increasingly accessible to the public. However, open big data relevant to travelers within public transit tools remain scarce, hindering any further in-depth study on human mobility patterns. Here, we explore ticketing-website derived data that are publically available but have been largely neglected. We demonstrate the power, potential and limitations of this open big data, using the Chinese high-speed rail (HSR) system as an example. Using an application programming interface, we automatically collected the data on the remaining tickets (RTD) for scheduled trains at the last second before departure in order to retrieve information on unused transit capacity, occupancy rate of trains, and passenger flux at stations. We show that this information is highly useful in characterizing the spatiotemporal patterns of traveling behaviors on the Chinese HSR, such as weekend traveling behavior, imbalanced commuting behavior, and station functionality. Our work facilitates the understanding of human traveling patterns along the Chinese HSR, and the functionality of the largest HSR system in the world. We expect our work to attract attention regarding this unique open big data source for the study of analogous transportation systems.

Improvement of automatic control systems of high-power turbines of PAO tubroatom for nuclear power plants

NASA Astrophysics Data System (ADS)

Shvetsov, V. L.; Babaev, I. N.

2017-09-01

The main technical solutions applied by PAO Turboatom used as the compensatory measures at the increase of the period of nonstop operation of nuclear power plants' (NPP) turbines with VVER-1000 type reactors up to 18 months are (1) replacing the standard hydraulic speed controller with an electronic one, (2) introduction of overclocking protection, (3) modernization of units of stop-control valves of high pressures, (4) installation of locking dampers on the receiver tubes of turbines of the first and second modification, and (5) improving the quality of repairs by reviewing the requirements for their implementation. The introduction of complex diagnostics of a control system on the basis of automatic treatment of results of registration of working parameters of the turbine is allocated as a separate prospective direction. Using an electronic controller of speed makes it possible to simplify the procedure of its inclusion in work at the failure of an electro-hydraulic system of control and vice versa. The regimes of maintaining the turbine rotor speed, steam pressure on the outlet of turbine, and the positions of main servomotors were introduced into the functions of the electronic controller. An electronic controller of speed includes its own electro-hydraulic transducer, turbine rotor speed sensor, and sensors of the position of main servomotors. Into the functions of electro- hydraulic control system and electronic speed controller, the function of overclocking protection, which determines the formation of commands for stopping the turbine at the exceeding of both the defined level of rotation speed and the defined combination of achieved rotation speed and angular acceleration of rotor, was introduced. To simplify the correction of forces acting on the control valve cups, the design of the cups was changed, and it has the profiled inserts. The solutions proposed were implemented on K-1100-60/1500-2M turbines of Rostov NPP. From the composition of control system of already made turbines, the devices of speed switching of moving of control flaps for opening and hydraulic damper in the servomotors of regulating flaps were excluded; the fists of the control valves providing the increased valve stroke for opening and the construction of filters for regulation, electro-hydraulic converters, oil draining device, etc. was changed.

Quantitative high-speed laryngoscopic analysis of vocal fold vibration in fatigued voice of young karaoke singers.

PubMed

Yiu, Edwin M-L; Wang, Gaowu; Lo, Andy C Y; Chan, Karen M-K; Ma, Estella P-M; Kong, Jiangping; Barrett, Elizabeth Ann

2013-11-01

The present study aimed to determine whether there were physiological differences in the vocal fold vibration between nonfatigued and fatigued voices using high-speed laryngoscopic imaging and quantitative analysis. Twenty participants aged from 18 to 23 years (mean, 21.2 years; standard deviation, 1.3 years) with normal voice were recruited to participate in an extended singing task. Vocal fatigue was induced using a singing task. High-speed laryngoscopic image recordings of /i/ phonation were taken before and after the singing task. The laryngoscopic images were semiautomatically analyzed with the quantitative high-speed video processing program to extract indices related to the anteroposterior dimension (length), transverse dimension (width), and the speed of opening and closing. Significant reduction in the glottal length-to-width ratio index was found after vocal fatigue. Physiologically, this indicated either a significantly shorter (anteroposteriorly) or a wider (transversely) glottis after vocal fatigue. The high-speed imaging technique using quantitative analysis has the potential for early identification of vocally fatigued voice. Copyright © 2013 The Voice Foundation. All rights reserved.

14 CFR 23.255 - Out of trim characteristics.

Code of Federal Regulations, 2013 CFR

2013-01-01

... apply: (a) From an initial condition with the airplane trimmed at cruise speeds up to VMO/MMO, the... speeds between VFC/MFC and VDF/MDF , the direction of the primary longitudinal control force may not... control force, flight tests must be accomplished from the normal acceleration at which a marginal...

Breaking the speed limit--comparative sprinting performance of brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta)

USGS Publications Warehouse

Castro-Santos, Theodore; Sanz-Ronda, Francisco Javier; Ruiz-Legazpi, Jorge

2013-01-01

Sprinting behavior of free-ranging fish has long been thought to exceed that of captive fish. Here we present data from wild-caught brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta), volitionally entering and sprinting against high-velocity flows in an open-channel flume. Performance of the two species was nearly identical, with the species attaining absolute speeds > 25 body lengths·s−1. These speeds far exceed previously published observations for any salmonid species and contribute to the mounting evidence that commonly accepted estimates of swimming performance are low. Brook trout demonstrated two distinct modes in the relationship between swim speed and fatigue time, similar to the shift from prolonged to sprint mode described by other authors, but in this case occurring at speeds > 19 body lengths·s−1. This is the first demonstration of multiple modes of sprint swimming at such high swim speeds. Neither species optimized for distance maximization, however, indicating that physiological limits alone are poor predictors of swimming performance. By combining distributions of volitional swim speeds with endurance, we were able to account for >80% of the variation in distance traversed by both species.

Fundamental Physics and Practical Applications of Electromagnetic Local Flow Control in High Speed Flows (Rutgers)

DTIC Science & Technology

2010-02-16

field. Techniques utilizing this design use an open- loop control and no flow monitoring sensors are required. Conversely, reactive (or closed - loop ...and closed (dashed line) configuration. 38 closed configuration described above, the ambiguity in the critical limits of the transition...flow; a new vortex is then shed from the cavity leading edge, closing the feedback loop .[31] Open cavities with an L/D approximately greater than

A surface renewal model for unsteady-state mass transfer using the generalized Danckwerts age distribution function.

PubMed

Horvath, Isabelle R; Chatterjee, Siddharth G

2018-05-01

The recently derived steady-state generalized Danckwerts age distribution is extended to unsteady-state conditions. For three different wind speeds used by researchers on air-water heat exchange on the Heidelberg Aeolotron, calculations reveal that the distribution has a sharp peak during the initial moments, but flattens out and acquires a bell-shaped character with process time, with the time taken to attain a steady-state profile being a strong and inverse function of wind speed. With increasing wind speed, the age distribution narrows significantly, its skewness decreases and its peak becomes larger. The mean eddy renewal time increases linearly with process time initially but approaches a final steady-state value asymptotically, which decreases dramatically with increased wind speed. Using the distribution to analyse the transient absorption of a gas into a large body of liquid, assuming negligible gas-side mass-transfer resistance, estimates are made of the gas-absorption and dissolved-gas transfer coefficients for oxygen absorption in water at 25°C for the three different wind speeds. Under unsteady-state conditions, these two coefficients show an inverse behaviour, indicating a heightened accumulation of dissolved gas in the surface elements, especially during the initial moments of absorption. However, the two mass-transfer coefficients start merging together as the steady state is approached. Theoretical predictions of the steady-state mass-transfer coefficient or transfer velocity are in fair agreement (average absolute error of prediction = 18.1%) with some experimental measurements of the same for the nitrous oxide-water system at 20°C that were made in the Heidelberg Aeolotron.

Kindergarten to College (K2C): A First-in-the-Nation Initiative to Set All Kindergartners on the Path to College. Asset Building Program

ERIC Educational Resources Information Center

Phillips, Leigh; Stuhldreher, Anne

2011-01-01

In the Spring of 2011, the City of San Francisco automatically opened college savings accounts for over 1,000 San Francisco Kindergartners. The City also "seeded" every account with an initial deposit of $50. The account openings marked the official launch of San Francisco's Kindergarten to College initiative, or "K2C." This initiative, the first…

Duke Surgery Patient Safety: an open-source application for anonymous reporting of adverse and near-miss surgical events

PubMed Central

Pietrobon, Ricardo; Lima, Raquel; Shah, Anand; Jacobs, Danny O; Harker, Matthew; McCready, Mariana; Martins, Henrique; Richardson, William

2007-01-01

Background Studies have shown that 4% of hospitalized patients suffer from an adverse event caused by the medical treatment administered. Some institutions have created systems to encourage medical workers to report these adverse events. However, these systems often prove to be inadequate and/or ineffective for reviewing the data collected and improving the outcomes in patient safety. Objective To describe the Web-application Duke Surgery Patient Safety, designed for the anonymous reporting of adverse and near-miss events as well as scheduled reporting to surgeons and hospital administration. Software architecture DSPS was developed primarily using Java language running on a Tomcat server and with MySQL database as its backend. Results Formal and field usability tests were used to aid in development of DSPS. Extensive experience with DSPS at our institution indicate that DSPS is easy to learn and use, has good speed, provides needed functionality, and is well received by both adverse-event reporters and administrators. Discussion This is the first description of an open-source application for reporting patient safety, which allows the distribution of the application to other institutions in addition for its ability to adapt to the needs of different departments. DSPS provides a mechanism for anonymous reporting of adverse events and helps to administer Patient Safety initiatives. Conclusion The modifiable framework of DSPS allows adherence to evolving national data standards. The open-source design of DSPS permits surgical departments with existing reporting mechanisms to integrate them with DSPS. The DSPS application is distributed under the GNU General Public License. PMID:17472749

Duke Surgery Patient Safety: an open-source application for anonymous reporting of adverse and near-miss surgical events.

PubMed

Pietrobon, Ricardo; Lima, Raquel; Shah, Anand; Jacobs, Danny O; Harker, Matthew; McCready, Mariana; Martins, Henrique; Richardson, William

2007-05-01

Studies have shown that 4% of hospitalized patients suffer from an adverse event caused by the medical treatment administered. Some institutions have created systems to encourage medical workers to report these adverse events. However, these systems often prove to be inadequate and/or ineffective for reviewing the data collected and improving the outcomes in patient safety. To describe the Web-application Duke Surgery Patient Safety, designed for the anonymous reporting of adverse and near-miss events as well as scheduled reporting to surgeons and hospital administration. SOFTWARE ARCHITECTURE: DSPS was developed primarily using Java language running on a Tomcat server and with MySQL database as its backend. Formal and field usability tests were used to aid in development of DSPS. Extensive experience with DSPS at our institution indicate that DSPS is easy to learn and use, has good speed, provides needed functionality, and is well received by both adverse-event reporters and administrators. This is the first description of an open-source application for reporting patient safety, which allows the distribution of the application to other institutions in addition for its ability to adapt to the needs of different departments. DSPS provides a mechanism for anonymous reporting of adverse events and helps to administer Patient Safety initiatives. The modifiable framework of DSPS allows adherence to evolving national data standards. The open-source design of DSPS permits surgical departments with existing reporting mechanisms to integrate them with DSPS. The DSPS application is distributed under the GNU General Public License.

Rise Time Reduction of Thermal Actuators Operated in Air and Water through Optimized Pre-Shaped Open-Loop Driving.

PubMed

Larsen, T; Doll, J C; Loizeau, F; Hosseini, N; Peng, A W; Fantner, G; Ricci, A J; Pruitt, B L

2017-01-01

Electrothermal actuators have many advantages compared to other actuators used in Micro-Electro-Mechanical Systems (MEMS). They are simple to design, easy to fabricate and provide large displacements at low voltages. Low voltages enable less stringent passivation requirements for operation in liquid. Despite these advantages, thermal actuation is typically limited to a few kHz bandwidth when using step inputs due to its intrinsic thermal time constant. However, the use of pre-shaped input signals offers a route for reducing the rise time of these actuators by orders of magnitude. We started with an electrothermally actuated cantilever having an initial 10-90% rise time of 85 μs in air and 234 μs in water for a standard open-loop step input. We experimentally characterized the linearity and frequency response of the cantilever when operated in air and water, allowing us to obtain transfer functions for the two cases. We used these transfer functions, along with functions describing desired reduced rise-time system responses, to numerically simulate the required input signals. Using these pre-shaped input signals, we improved the open-loop 10-90% rise time from 85 μs to 3 μs in air and from 234 μs to 5 μs in water, an improvement by a factor of 28 and 47, respectively. Using this simple control strategy for MEMS electrothermal actuators makes them an attractive alternative to other high speed micromechanical actuators such as piezoelectric stacks or electrostatic comb structures which are more complex to design, fabricate, or operate.

Flying Qualities (Qualites de Vol)

DTIC Science & Technology

1991-02-01

a typical lan-ling condition ,n " High kift’ý confirpurati.on, low speed , goar down, No criticaitiss come tip from the liy-ear...lateral canitol tark. In case of low~ speed , high dive ang~le or, for delayel bombe, ( i-e. i/ A > " ) , CMh’. f,7eqvtiacy responsev curlve moves toward the...approach case or the initial slope manoeuvre limiting or carefree handling of a non-lirear command in a . high speed facilities will usually have

Contributions of muscles and passive dynamics to swing initiation over a range of walking speeds.

PubMed

Fox, Melanie D; Delp, Scott L

2010-05-28

Stiff-knee gait is a common walking problem in cerebral palsy characterized by insufficient knee flexion during swing. To identify factors that may limit knee flexion in swing, it is necessary to understand how unimpaired subjects successfully coordinate muscles and passive dynamics (gravity and velocity-related forces) to accelerate the knee into flexion during double support, a critical phase just prior to swing that establishes the conditions for achieving sufficient knee flexion during swing. It is also necessary to understand how contributions to swing initiation change with walking speed, since patients with stiff-knee gait often walk slowly. We analyzed muscle-driven dynamic simulations of eight unimpaired subjects walking at four speeds to quantify the contributions of muscles, gravity, and velocity-related forces (i.e. Coriolis and centrifugal forces) to preswing knee flexion acceleration during double support at each speed. Analysis of the simulations revealed contributions from muscles and passive dynamics varied systematically with walking speed. Preswing knee flexion acceleration was achieved primarily by hip flexor muscles on the preswing leg with assistance from biceps femoris short head. Hip flexors on the preswing leg were primarily responsible for the increase in preswing knee flexion acceleration during double support with faster walking speed. The hip extensors and abductors on the contralateral leg and velocity-related forces opposed preswing knee flexion acceleration during double support. Copyright 2010 Elsevier Ltd. All rights reserved.

Contributions of muscles and passive dynamics to swing initiation over a range of walking speeds

PubMed Central

Fox, Melanie D.; Delp, Scott L.

2010-01-01

Stiff-knee gait is a common walking problem in cerebral palsy characterized by insufficient knee flexion during swing. To identify factors that may limit knee flexion in swing, it is necessary to understand how unimpaired subjects successfully coordinate muscles and passive dynamics (gravity and velocity-related forces) to accelerate the knee into flexion during double support, a critical phase just prior to swing that establishes the conditions for achieving sufficient knee flexion during swing. It is also necessary to understand how contributions to swing initiation change with walking speed, since patients with stiff-knee gait often walk slowly. We analyzed muscle-driven dynamic simulations of eight unimpaired subjects walking at four speeds to quantify the contributions of muscles, gravity, and velocity-related forces (i.e. Coriolis and centrifugal forces) to preswing knee flexion acceleration during double support at each speed. Analysis of the simulations revealed contributions from muscles and passive dynamics varied systematically with walking speed. Preswing knee flexion acceleration was achieved primarily by hip flexor muscles on the preswing leg with assistance from biceps femoris short head. Hip flexors on the preswing leg were primarily responsible for the increase in preswing knee flexion acceleration during double support with faster walking speed. The hip extensors and abductors on the contralateral leg and velocity-related forces opposed preswing knee flexion acceleration during double support. PMID:20236644

A Free-flight Wind Tunnel for Aerodynamic Testing at Hypersonic Speeds

NASA Technical Reports Server (NTRS)

Seiff, Alvin

1954-01-01

The supersonic free-flight wind tunnel is a facility at the Ames Laboratory of the NACA in which aerodynamic test models are gun-launched at high speed and directed upstream through the test section of a supersonic wind tunnel. In this way, test Mach numbers up to 10 have been attained and indications are that still higher speeds will be realized. An advantage of this technique is that the air and model temperatures simulate those of flight through the atmosphere. Also the Reynolds numbers are high. Aerodynamic measurements are made from photographic observation of the model flight. Instruments and techniques have been developed for measuring the following aerodynamic properties: drag, initial lift-curve slope, initial pitching-moment-curve slope, center of pressure, skin friction, boundary-layer transition, damping in roll, and aileron effectiveness. (author)

MHD Modelling of Coronal Loops: Injection of High-Speed Chromospheric Flows

NASA Technical Reports Server (NTRS)

Petralia, A.; Reale, F.; Orlando, S.; Klimchuk, J. A.

2014-01-01

Context. Observations reveal a correspondence between chromospheric type II spicules and bright upward-moving fronts in the corona observed in the extreme-ultraviolet (EUV) band. However, theoretical considerations suggest that these flows are probably not the main source of heating in coronal magnetic loops. Aims. We investigate the propagation of high-speed chromospheric flows into coronal magnetic flux tubes and the possible production of emission in the EUV band. Methods. We simulated the propagation of a dense 104 K chromospheric jet upward along a coronal loop by means of a 2D cylindrical MHD model that includes gravity, radiative losses, thermal conduction, and magnetic induction. The jet propagates in a complete atmosphere including the chromosphere and a tenuous cool (approximately 0.8 MK) corona, linked through a steep transition region. In our reference model, the jet initial speed is 70 km per second, its initial density is 10(exp 11) per cubic centimeter, and the ambient uniform magnetic field is 10 G. We also explored other values of jet speed and density in 1D and different magnetic field values in 2D, as well as the jet propagation in a hotter (approximately 1.5 MK) background loop. Results. While the initial speed of the jet does not allow it to reach the loop apex, a hot shock-front develops ahead of it and travels to the other extreme of the loop. The shock front compresses the coronal plasma and heats it to about 10(exp 6) K. As a result, a bright moving front becomes visible in the 171 Angstrom channel of the SDO/AIA mission. This result generally applies to all the other explored cases, except for the propagation in the hotter loop. Conclusions. For a cool, low-density initial coronal loop, the post-shock plasma ahead of upward chromospheric flows might explain at least part of the observed correspondence between type II spicules and EUV emission excess.

Imaging initial formation processes of nanobubbles at the graphite-water interface through high-speed atomic force microscopy

NASA Astrophysics Data System (ADS)

Liao, Hsien-Shun; Yang, Chih-Wen; Ko, Hsien-Chen; Hwu, En-Te; Hwang, Ing-Shouh

2018-03-01

The initial formation process of nanobubbles at solid-water interfaces remains unclear because of the limitations of current imaging techniques. To directly observe the formation process, an astigmatic high-speed atomic force microscope (AFM) was modified to enable imaging in the liquid environment. By using a customized cantilever holder, the resonance of small cantilevers was effectively enhanced in water. The proposed high-speed imaging technique yielded highly dynamic quasi-two-dimensional (2D) gas structures (thickness: 20-30 nm) initially at the graphite-water interface. The 2D structures were laterally mobile mainly within certain areas, but occasionally a gas structure might extensively migrate and settle in a new area. The 2D structures were often confined by substrate step edges in one lateral dimension. Eventually, all quasi-2D gas structures were transformed into cap-shaped nanobubbles of higher heights and reduced lateral dimensions. These nanobubbles were immobile and remained stable under continuous AFM imaging. This study demonstrated that nanobubbles could be stably imaged at a scan rate of 100 lines per second (640 μm/s).

Unified hatch system

NASA Technical Reports Server (NTRS)

Hart, R. J.; Walkover, L. J.; Zosky, E. W.

1971-01-01

Special hatch sealing mechanism design increases safety, reliability, and convenience. Adaptations are possible for oceanographic and high-speed aircraft design, or for any system where quick-opening pressure hatch is required. In normal mode, hatching mechanism is manually operated from either side.

Social network based dynamic transit service through the OMITS system.

DOT National Transportation Integrated Search

2014-02-01

The Open Mode Integrated Transportation System (OMITS) forms a sustainable information infrastructure for communication within and between the mobile/Internet network, the roadway : network, and the users social network. It manipulates the speed g...

The OpenCalphad thermodynamic software interface.

PubMed

Sundman, Bo; Kattner, Ursula R; Sigli, Christophe; Stratmann, Matthias; Le Tellier, Romain; Palumbo, Mauro; Fries, Suzana G

2016-12-01

Thermodynamic data are needed for all kinds of simulations of materials processes. Thermodynamics determines the set of stable phases and also provides chemical potentials, compositions and driving forces for nucleation of new phases and phase transformations. Software to simulate materials properties needs accurate and consistent thermodynamic data to predict metastable states that occur during phase transformations. Due to long calculation times thermodynamic data are frequently pre-calculated into "lookup tables" to speed up calculations. This creates additional uncertainties as data must be interpolated or extrapolated and conditions may differ from those assumed for creating the lookup table. Speed and accuracy requires that thermodynamic software is fully parallelized and the Open-Calphad (OC) software is the first thermodynamic software supporting this feature. This paper gives a brief introduction to computational thermodynamics and introduces the basic features of the OC software and presents four different application examples to demonstrate its versatility.

The OpenCalphad thermodynamic software interface

PubMed Central

Sundman, Bo; Kattner, Ursula R; Sigli, Christophe; Stratmann, Matthias; Le Tellier, Romain; Palumbo, Mauro; Fries, Suzana G

2017-01-01

Thermodynamic data are needed for all kinds of simulations of materials processes. Thermodynamics determines the set of stable phases and also provides chemical potentials, compositions and driving forces for nucleation of new phases and phase transformations. Software to simulate materials properties needs accurate and consistent thermodynamic data to predict metastable states that occur during phase transformations. Due to long calculation times thermodynamic data are frequently pre-calculated into “lookup tables” to speed up calculations. This creates additional uncertainties as data must be interpolated or extrapolated and conditions may differ from those assumed for creating the lookup table. Speed and accuracy requires that thermodynamic software is fully parallelized and the Open-Calphad (OC) software is the first thermodynamic software supporting this feature. This paper gives a brief introduction to computational thermodynamics and introduces the basic features of the OC software and presents four different application examples to demonstrate its versatility. PMID:28260838

GPU-based real-time trinocular stereo vision

NASA Astrophysics Data System (ADS)

Yao, Yuanbin; Linton, R. J.; Padir, Taskin

2013-01-01

Most stereovision applications are binocular which uses information from a 2-camera array to perform stereo matching and compute the depth image. Trinocular stereovision with a 3-camera array has been proved to provide higher accuracy in stereo matching which could benefit applications like distance finding, object recognition, and detection. This paper presents a real-time stereovision algorithm implemented on a GPGPU (General-purpose graphics processing unit) using a trinocular stereovision camera array. Algorithm employs a winner-take-all method applied to perform fusion of disparities in different directions following various image processing techniques to obtain the depth information. The goal of the algorithm is to achieve real-time processing speed with the help of a GPGPU involving the use of Open Source Computer Vision Library (OpenCV) in C++ and NVidia CUDA GPGPU Solution. The results are compared in accuracy and speed to verify the improvement.

Opening-mode cracking in asphalt pavements : crack initiation and saturation.

DOT National Transportation Integrated Search

2009-12-01

This paper investigates the crack initiation and saturation for opening-mode cracking. Using elastic governing equations : and a weak form stress boundary condition, we derive an explicit solution of elastic fields in the surface course and : obtain ...

Assessment of Different Discrete Particle Methods Ability To Predict Gas-Particle Flow in a Small-Scale Fluidized Bed

DOE PAGES

Lu, Liqiang; Gopalan, Balaji; Benyahia, Sofiane

2017-06-21

Several discrete particle methods exist in the open literature to simulate fluidized bed systems, such as discrete element method (DEM), time driven hard sphere (TDHS), coarse-grained particle method (CGPM), coarse grained hard sphere (CGHS), and multi-phase particle-in-cell (MP-PIC). These different approaches usually solve the fluid phase in a Eulerian fixed frame of reference and the particle phase using the Lagrangian method. The first difference between these models lies in tracking either real particles or lumped parcels. The second difference is in the treatment of particle-particle interactions: by calculating collision forces (DEM and CGPM), using momentum conservation laws (TDHS and CGHS),more » or based on particle stress model (MP-PIC). These major model differences lead to a wide range of results accuracy and computation speed. However, these models have never been compared directly using the same experimental dataset. In this research, a small-scale fluidized bed is simulated with these methods using the same open-source code MFIX. The results indicate that modeling the particle-particle collision by TDHS increases the computation speed while maintaining good accuracy. Also, lumping few particles in a parcel increases the computation speed with little loss in accuracy. However, modeling particle-particle interactions with solids stress leads to a big loss in accuracy with a little increase in computation speed. The MP-PIC method predicts an unphysical particle-particle overlap, which results in incorrect voidage distribution and incorrect overall bed hydrodynamics. Based on this study, we recommend using the CGHS method for fluidized bed simulations due to its computational speed that rivals that of MPPIC while maintaining a much better accuracy.« less

Assessment of Different Discrete Particle Methods Ability To Predict Gas-Particle Flow in a Small-Scale Fluidized Bed

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

Lu, Liqiang; Gopalan, Balaji; Benyahia, Sofiane

Several discrete particle methods exist in the open literature to simulate fluidized bed systems, such as discrete element method (DEM), time driven hard sphere (TDHS), coarse-grained particle method (CGPM), coarse grained hard sphere (CGHS), and multi-phase particle-in-cell (MP-PIC). These different approaches usually solve the fluid phase in a Eulerian fixed frame of reference and the particle phase using the Lagrangian method. The first difference between these models lies in tracking either real particles or lumped parcels. The second difference is in the treatment of particle-particle interactions: by calculating collision forces (DEM and CGPM), using momentum conservation laws (TDHS and CGHS),more » or based on particle stress model (MP-PIC). These major model differences lead to a wide range of results accuracy and computation speed. However, these models have never been compared directly using the same experimental dataset. In this research, a small-scale fluidized bed is simulated with these methods using the same open-source code MFIX. The results indicate that modeling the particle-particle collision by TDHS increases the computation speed while maintaining good accuracy. Also, lumping few particles in a parcel increases the computation speed with little loss in accuracy. However, modeling particle-particle interactions with solids stress leads to a big loss in accuracy with a little increase in computation speed. The MP-PIC method predicts an unphysical particle-particle overlap, which results in incorrect voidage distribution and incorrect overall bed hydrodynamics. Based on this study, we recommend using the CGHS method for fluidized bed simulations due to its computational speed that rivals that of MPPIC while maintaining a much better accuracy.« less

Arm-trunk coordination in wheelchair initiation displacement: A study of anticipatory and compensatory postural adjustments during different speeds and directions of propulsion.

PubMed

Chikh, Soufien; Garnier, Cyril; Faupin, Arnaud; Pinti, Antonio; Boudet, Samuel; Azaiez, Fairouz; Watelain, Eric

2018-06-01

Arm-trunk coordination during the initiation of displacement in manual wheelchair is a complex task. The objective of this work is to study the arm-trunk coordination by measuring anticipatory and compensatory postural adjustments. Nine healthy subjects participated in the study after being trained in manual wheelchair. They were asked to initiate a displacement in manual wheelchair in three directions (forward vs. left vs. right), with two speeds (spontaneous vs. maximum) and with two initial hand's positions (hands on thighs vs. hands on handrails). Muscular activities in the trunk (postural component) and the arms (focal component) were recorded bilaterally. The results show two strategies for trunk control: An anticipatory adjustment strategy and a compensatory adjustment strategy with a dominance of compensation. These two strategies are influenced by the finalities of displacement in terms of speed and direction depending on the hands positions. Arm-trunk coordination is characterized by an adaptability of anticipatory and compensatory postural adjustments. The study of this type of coordination for subjects with different levels of spinal cord injury could be used to predict the forthcoming displacement and thus assist the user in a complex task. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dynamic delamination crack propagation in a graphite/epoxy laminate

NASA Technical Reports Server (NTRS)

Grady, J. E.; Sun, C. T.

1991-01-01

Dynamic delamination crack propagation in a (90/0) 5s Graphite/Epoxy laminate with an embedded interfacial crack was investigated experimentally using high speed photography. The dynamic motion was produced by impacting the beamlike laminate specimen with a silicon rubber ball. The threshold impact velocities required to initiate dynamic crack propagation in laminates with varying initial crack positions were determined. The crack propagation speeds were estimated from the photographs. Results show that the through the thickness position of the embedded crack can significantly affect the dominant mechanism and the threshold impact velocity for the onset of crack movement. If the initial delamination is placed near the top of bottom surface of the laminate, local buckling of the delaminated plies may cause instability of the crack. If the initial delamination lies on the midplane, local buckling does not occur and the initiation of crack propagation appears to be dominated by Mode II fracture. The crack propagation and arrest observed was seen to be affected by wave motion within the delamination region.

Influence of wind-speed on short-duration NO2 measurements using Palmes and Ogawa passive diffusion samplers

NASA Astrophysics Data System (ADS)

Masey, Nicola; Gillespie, Jonathan; Heal, Mathew R.; Hamilton, Scott; Beverland, Iain J.

2017-07-01

We assessed the precision and accuracy of nitrogen dioxide (NO2) concentrations over 2-day, 3-day and 7-day exposure periods measured with the following types of passive diffusion samplers: standard (open) Palmes tubes; standard Ogawa samplers with commercially-prepared Ogawa absorbent pads (Ogawa[S]); and modified Ogawa samplers with absorbent-impregnated stainless steel meshes normally used in Palmes tubes (Ogawa[P]). We deployed these passive samplers close to the inlet of a chemiluminescence NO2 analyser at an urban background site in Glasgow, UK over 32 discrete measurement periods. Duplicate relative standard deviation was <7% for all passive samplers. The Ogawa[P], Ogawa[S] and Palmes samplers explained 93%, 87% and 58% of temporal variation in analyser concentrations respectively. Uptake rates for Palmes and Ogawa[S] samplers were positively and linearly associated with wind-speed (P < 0.01 and P < 0.05 respectively). Computation of adjusted uptake rates using average wind-speed observed during each sampling period increased the variation in analyser concentrations explained by Palmes and Ogawa[S] estimates to 90% and 92% respectively, suggesting that measurements can be corrected for shortening of diffusion path lengths due to wind-speed to improve the accuracy of estimates of short-term NO2 exposure. Monitoring situations where it is difficult to reliably estimate wind-speed variations, e.g. across multiple sites with different unknown exposures to local winds, and personal exposure monitoring, are likely to benefit from protection of these sampling devices from the effects of wind, for example by use of a mesh or membrane across the open end. The uptake rate of Ogawa[P] samplers was not associated with wind-speed resulting in a high correlation between estimated concentrations and observed analyser concentrations. The use of Palmes meshes in Ogawa[P] samplers reduced the cost of sampler preparation and removed uncertainty associated with the unknown manufacturing process for the commercially-prepared collection pads.

Impact Depth and the Interaction with Impact Speed Affect the Severity of Contusion Spinal Cord Injury in Rats

PubMed Central

Lam, Cameron J.; Assinck, Peggy; Liu, Jie; Tetzlaff, Wolfram

2014-01-01

Abstract Spinal cord injury (SCI) biomechanics suggest that the mechanical factors of impact depth and speed affect the severity of contusion injury, but their interaction is not well understood. The primary aim of this work was to examine both the individual and combined effects of impact depth and speed in contusion SCI on the cervical spinal cord. Spinal cord contusions between C5 and C6 were produced in anesthetized rats at impact speeds of 8, 80, or 800 mm/s with displacements of 0.9 or 1.5 mm (n=8/group). After 7 days postinjury, rats were assessed for open-field behavior, euthanized, and spinal cords were harvested. Spinal cord tissue sections were stained for demyelination (myelin-based protein) and tissue sparing (Luxol fast blue). In parallel, a finite element model of rat spinal cord was used to examine the resulting maximum principal strain in the spinal cord during impact. Increasing impact depth from 0.9 to 1.5 mm reduced open-field scores (p<0.01) above 80 mm/s, reduced gray (GM) and white matter (WM) sparing (p<0.01), and increased the amount of demyelination (p<0.01). Increasing impact speed showed similar results at the 1.5-mm impact depth, but not the 0.9-mm impact depth. Linear correlation analysis with finite element analysis strain showed correlations (p<0.001) with nerve fiber damage in the ventral (R2=0.86) and lateral (R2=0.74) regions of the spinal cord and with WM (R2=0.90) and GM (R2=0.76) sparing. The results demonstrate that impact depth is more important in determining the severity of SCI and that threshold interactions exist between impact depth and speed. PMID:24945364

Fuzzy adaptive strong tracking scaled unscented Kalman filter for initial alignment of large misalignment angles

NASA Astrophysics Data System (ADS)

Li, Jing; Song, Ningfang; Yang, Gongliu; Jiang, Rui

2016-07-01

In the initial alignment process of strapdown inertial navigation system (SINS), large misalignment angles always bring nonlinear problem, which can usually be processed using the scaled unscented Kalman filter (SUKF). In this paper, the problem of large misalignment angles in SINS alignment is further investigated, and the strong tracking scaled unscented Kalman filter (STSUKF) is proposed with fixed parameters to improve convergence speed, while these parameters are artificially constructed and uncertain in real application. To further improve the alignment stability and reduce the parameters selection, this paper proposes a fuzzy adaptive strategy combined with STSUKF (FUZZY-STSUKF). As a result, initial alignment scheme of large misalignment angles based on FUZZY-STSUKF is designed and verified by simulations and turntable experiment. The results show that the scheme improves the accuracy and convergence speed of SINS initial alignment compared with those based on SUKF and STSUKF.

Characterisation of an Exploding Foil Initiator (EFI) system

NASA Astrophysics Data System (ADS)

Davies, H. R.; Chapman, D. J.; Vine, T. A.; Proud, W. G.

2009-06-01

Exploding Foil Initiators (EFIs) provide a safe and reliable means of detonation of explosives. They are highly insensitive to mechanical shock and electrical interference, requiring a specific high current pulse for initiation. The use of only insensitive secondary explosives and not more sensitive primary explosives further improves safety. When a high current is passed through the metal bridge, a plasma is formed as the metal can not expand beyond the polymer film layer above. This causes the film to expand forming a bubble or shearing off to form a flyer. These flyers can then be used to initiate secondary explosives. Due to the very high speed at which these systems operate, high speed streak photography was used to characterise the behaviour of the polymer film flyers produced. This paper will report the preliminary findings on the mechanical, electrical and velocity changes seen in some proprietary systems.

[The Open Access Initiative (OAI) in the scientific literature].

PubMed

Sánchez-Martín, Francisco M; Millán Rodríguez, Félix; Villavicencio Mavrich, Humberto

2009-01-01

According to the declaration of the Budapest Open Access Initiative (OAI) is defined as a editorial model in which access to scientific journal literature and his use are free. Free flow of information allowed by Internet has been the basis of this initiative. The Bethesda and the Berlin declarations, supported by some international agencies, proposes to require researchers to deposit copies of all articles published in a self-archive or an Open Access repository, and encourage researchers to publish their research papers in journals Open Access. This paper reviews the keys of the OAI, with their strengths and controversial aspects; and it discusses the position of databases, search engines and repositories of biomedical information, as well as the attitude of the scientists, publishers and journals. So far the journal Actas Urológicas Españolas (Act Urol Esp) offer their contents on Open Access as On Line in Spanish and English.

Cognitive function in early HIV infection.

PubMed

Prakash, Aanchal; Hou, Jue; Liu, Lei; Gao, Yi; Kettering, Casey; Ragin, Ann B

2017-04-01

This study aimed to examine cognitive function in acute/early HIV infection over the subsequent 2 years. Fifty-six HIV+ subjects and 21 seronegative participants of the Chicago Early HIV Infection Study were evaluated using a comprehensive neuropsychological assessment at study enrollment and at 2-year follow-up. Cognitive performance measures were compared in the groups using t tests and mixed-effect models. Patterns of relationship with clinical measures were determined between cognitive function and clinical status markers using Spearman's correlations. At the initial timepoint, the HIV group demonstrated significantly weaker performance on measures of verbal memory, visual memory, psychomotor speed, motor speed, and executive function. A similar pattern was found when cognitive function was examined at follow-up and across both timepoints. The HIV subjects had generally weaker performance on psychomotor speed, executive function, motor speed, visual memory, and verbal memory. The rate of decline in cognitive function across the 2-year follow-up period did not differ between groups. Correlations between clinical status markers and cognitive function at both timepoints showed weaker performance associated with increased disease burden. Neurocognitive difficulty in chronic HIV infection may have very early onset and reflect consequences of initial brain viral invasion and neuroinflammation during the intense, uncontrolled viremia of acute HIV infection. Further characterization of the changes occurring in initial stages of infection and the risk and protective factors for cognitive function could inform new strategies for neuroprotection.

Lateralized Motor Control Processes Determine Asymmetry of Interlimb Transfer

PubMed Central

Sainburg, Robert L.; Schaefer, Sydney Y.; Yadav, Vivek

2016-01-01

This experiment tested the hypothesis that interlimb transfer of motor performance depends on recruitment of motor control processes that are specialized to the hemisphere contralateral to the arm that is initially trained. Right-handed participants performed a single-joint task, in which reaches were targeted to 4 different distances. While the speed and accuracy was similar for both hands, the underlying control mechanisms used to vary movement speed with distance were systematically different between the arms: The amplitude of the initial acceleration profiles scaled greater with movement speed for the right-dominant arm, while the duration of the initial acceleration profile scaled greater with movement speed for the left-non-dominant arm. These two processes were previously shown to be differentially disrupted by left and right hemisphere damage, respectively. We now hypothesize that task practice with the right arm might reinforce left-hemisphere mechanisms that vary acceleration amplitude with distance, while practice with the left arm might reinforce right-hemisphere mechanisms that vary acceleration duration with distance. We thus predict that following right arm practice, the left arm should show increased contributions of acceleration amplitude to peak velocities, and following left arm practice, the right arm should show increased contributions of acceleration duration to peak velocities. Our findings support these predictions, indicating that asymmetry in interlimb transfer of motor performance, at least in the task used here, depends on recruitment of lateralized motor control processes. PMID:27491479

A model to relate wind tunnel measurements to open field odorant emissions from liquid area sources

NASA Astrophysics Data System (ADS)

Lucernoni, F.; Capelli, L.; Busini, V.; Sironi, S.

2017-05-01

Waste Water Treatment Plants are known to have significant emissions of several pollutants and odorants causing nuisance to the near-living population. One of the purposes of the present work is to study a suitable model to evaluate odour emissions from liquid passive area sources. First, the models describing volatilization under a forced convection regime inside a wind tunnel device, which is the sampling device that typically used for sampling on liquid area sources, were investigated. In order to relate the fluid dynamic conditions inside the hood to the open field and inside the hood a thorough study of the models capable of describing the volatilization phenomena of the odorous compounds from liquid pools was performed and several different models were evaluated for the open field emission. By means of experimental tests involving pure liquid acetone and pure liquid butanone, it was verified that the model more suitable to describe precisely the volatilization inside the sampling hood is the model for the emission from a single flat plate in forced convection and laminar regime, with a fluid dynamic boundary layer fully developed and a mass transfer boundary layer not fully developed. The proportionality coefficient for the model was re-evaluated in order to account for the specific characteristics of the adopted wind tunnel device, and then the model was related with the selected model for the open field thereby computing the wind speed at 10 m that would cause the same emission that is estimated from the wind tunnel measurement furthermore, the field of application of the proposed model was clearly defined for the considered models during the project, discussing the two different kinds of compounds commonly found in emissive liquid pools or liquid spills, i.e. gas phase controlled and liquid phase controlled compounds. Lastly, a discussion is presented comparing the presented approach for emission rates recalculation in the field, with other approaches possible, i.e. the ones relying on the recalculation of the wind speed at the emission level, instead of the wind speed that would cause in the open field the same emission that is measured with the hood.

DOD Open Government

Science.gov Websites

Skip to main content (Press Enter). DOD Open Government Logo DOD Open Government U.S. Department of Defense Search DOD Open Government: Home Open Government @ DoD Transparency Congressional Inquiries Cooperation Regulatory Program Initiatives FRD Declassification DARPA Open Catalog Contact Us 2016

Nurses' behaviour regarding CPR and the theories of reasoned action and planned behaviour.

PubMed

Dwyer, Trudy; Mosel Williams, Leonie

2002-01-01

Cardiopulmonary resuscitation (CPR) has been used in hospitals for approximately 40 years. Nurses are generally the first responders to a cardiac arrest and initiate basic life support while waiting for the advanced cardiac life support team to arrive. Speed and competence of the first responder are factors contributing to the initial survival of a person following a cardiac arrest. Attitudes of individual nurses may influence the speed and level of involvement in true emergency situations. This paper uses the theories of reasoned action and planned behaviour to examine some behavioural issues with CPR involvement.

Experimental study of the penetrating of plates by projectile at low initial speeds

NASA Astrophysics Data System (ADS)

Orlov, M. Yu; Orlova, Yu N.; Smakotin, Ig L.; Glazyrin, V. P.; Orlov, Yu N.

2017-11-01

The research of the penetration process of lightweight plates by a projectile in the range of initial velocities up to 325 m/s was attempted. The projectile was a shell bullet and the barriers were of ice, MDF-panels and plexiglas barriers. The response of barriers to impact loading is studied. High-speed shooting of each experiment is obtained, including photos of the front and rear sides of the barriers. An attempt was made to reproduce the scenario of the destruction of barriers. The results of experiments can be interpreted only as qualitative tests. Projectile was not destroyed.

Prism adaptation speeds reach initiation in the direction of the prism after-effect.

PubMed

Striemer, Christopher L; Borza, Carley A

2017-10-01

Damage to the temporal-parietal cortex in the right hemisphere often leads to spatial neglect-a disorder in which patients are unable to attend to sensory input from their contralesional (left) side. Neglect has been associated with both attentional and premotor deficits. That is, in addition to having difficulty with attending to the left side, patients are often slower to initiate leftward vs. rightward movements (i.e., directional hypokinesia). Previous research has indicated that a brief period of adaptation to rightward shifting prisms can reduce symptoms of neglect by adjusting the patient's movements leftward, toward the neglected field. Although prism adaptation has been shown to reduce spatial attention deficits in patients with neglect, very little work has examined the effects of prisms on premotor symptoms. In the current study, we examined this in healthy individuals using leftward shifting prisms to induce a rightward shift in the egocentric reference frame, similar to neglect patients prior to prism adaptation. Specifically, we examined the speed with which healthy participants initiated leftward and rightward reaches (without visual feedback) prior to and following adaptation to either 17° leftward (n = 16) or 17° rightward (n = 15) shifting prisms. Our results indicated that, following adaptation, participants were significantly faster to initiate reaches towards targets located in the direction opposite the prism shift. That is, participants were faster to initiate reaches to right targets following leftward prism adaptation and were faster to initiate reaches to left targets following rightward prism adaptation. Overall, these results are consistent with the idea that prism adaptation can influence the speed with which a reach can be initiated toward a target in the direction opposite the prism shift, possibly through altering activity in neural circuits involved in reach planning.

Open Abdomen Therapy with Vacuum and Mesh Mediated Fascial Traction After Aortic Repair: an International Multicentre Study.

PubMed

Acosta, Stefan; Seternes, Arne; Venermo, Maarit; Vikatmaa, Leena; Sörelius, Karl; Wanhainen, Anders; Svensson, Mats; Djavani, Khatereh; Björck, Martin

2017-12-01

Open abdomen therapy may be necessary to prevent or treat abdominal compartment syndrome (ACS). The aim of the study was to analyse the primary delayed fascial closure (PDFC) rate and complications after open abdomen therapy with vacuum and mesh mediated fascial traction (VACM) after aortic repair and to compare outcomes between those treated with open abdomen after primary versus secondary operation. This was a retrospective cohort, multicentre study in Sweden, Finland, and Norway, including consecutive patients treated with open abdomen and VACM after aortic repair at six vascular centres in 2006-2015. The primary endpoint was PDFC rate. Among 191 patients, 155 were men. The median age was 71 years (IQR 66-76). Ruptured abdominal aortic aneurysm (RAAA) occurred in 69.1%. Endovascular/hybrid and open repairs were performed in 49 and 142 patients, respectively. The indications for open abdomen were inability to close the abdomen (62%) at primary operation and ACS (80%) at secondary operation. Duration of open abdomen was 11 days (IQR 7-16) in 157 patients alive at open abdomen termination. The PDFC rate was 91.8%. Open abdomen initiated at primary (N=103), compared with secondary operation (N=88), was associated with less severe initial open abdomen status (p=.006), less intestinal ischaemia (p=.002), shorter duration of open abdomen (p=.007), and less renal replacement therapy (RRT, p<.001). In hospital mortality was 39.3%, and after entero-atmospheric fistula (N=9) was 88.9%. Seven developed graft infection within 6 months, 1 year mortality was 28.6%. Intestinal ischaemia (OR 3.71, 95% CI 1.55-8.91), RRT (OR 3.62, 95% CI 1.72-7.65), and age (OR 1.12, 95% CI 1.06-1.12), were independent factors associated with in hospital mortality, but not open abdomen initiated at primary versus secondary operation. VACM was associated with a high PDFC rate after prolonged open abdomen therapy following aortic repair. Patient outcomes seemed better when open abdomen was initiated at primary, compared with secondary operation but a selection effect is possible. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Development of a high-specific-speed centrifugal compressor

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

Rodgers, C.

1997-07-01

This paper describes the development of a subscale single-stage centrifugal compressor with a dimensionless specific speed (Ns) of 1.8, originally designed for full-size application as a high volume flow, low pressure ratio, gas booster compressor. The specific stage is noteworthy in that it provides a benchmark representing the performance potential of very high-specific-speed compressors, of which limited information is found in the open literature. Stage and component test performance characteristics are presented together with traverse results at the impeller exit. Traverse test results were compared with recent CFD computational predictions for an exploratory analytical calibration of a very high-specific-speed impellermore » geometry. The tested subscale (0.583) compressor essentially satisfied design performance expectations with an overall stage efficiency of 74% including, excessive exit casing losses. It was estimated that stage efficiency could be increased to 81% with exit casing losses halved.« less

High-speed bipolar phototransistors in a 180 nm CMOS process.

PubMed

Kostov, P; Gaberl, W; Zimmermann, H

2013-03-01

Several high-speed pnp phototransistors built in a standard 180 nm CMOS process are presented. The phototransistors were implemented in sizes of 40×40 μm 2 and 100×100 μm 2 . Different base and emitter areas lead to different characteristics of the phototransistors. As starting material a p + wafer with a p - epitaxial layer on top was used. The phototransistors were optically characterized at wavelengths of 410, 675 and 850 nm. Bandwidths up to 92 MHz and dynamic responsivities up to 2.95 A/W were achieved. Evaluating the results, we can say that the presented phototransistors are well suited for high speed photosensitive optical applications where inherent amplification is needed. Further on, the standard silicon CMOS implementation opens the possibility for cheap integration of integrated optoelectronic circuits. Possible applications for the presented phototransistors are low cost high speed image sensors, opto-couplers, etc.

The impact of personality on driving safety among Chinese high-speed railway drivers.

PubMed

Guo, Ming; Wei, Wei; Liao, Ganli; Chu, Fulei

2016-07-01

This study explored the impact of personality traits on driving safety in high-speed railway drivers. A sample of high-speed railway drivers in Beijing (N=214) completed a questionnaire, including information on personality traits and background variables. The NEO Five Factor Inventory (NEO-FFI) was administered to characterize participants based on five personality traits: Neuroticism, Extraversion, Agreeableness, Openness to Experience, and Conscientiousness. The survey data were combined with naturalistic data of accident involvement and risky driving behavior in China. Poisson regression results show that drivers with high Conscientiousness and Extraversion caused fewer accidents. Higher Conscientiousness and lower Agreeableness were related to less frequent risky driving behavior. Education level and age negatively moderated the relation between certain personality traits and driving safety. The findings suggest that personality traits should be considered when selecting and training high-speed railway drivers. Copyright © 2016 Elsevier Ltd. All rights reserved.

An evaluation of the effects of tread depth, pavement texture, and water film thickness on skid number-speed gradients : supplement.

DOT National Transportation Integrated Search

1975-03-01

The raw data and the initial curves for the study entitled, "An Evaluation of the Effects of Tread Depth, Pavement Texture, and Water Film Thickness on Skid Number-Speed Gradients" are so voluminous that they are included in the Supplement rather tha...

RESISTIVE EXERCISES IN THE DEVELOPMENT OF MUSCULAR STRENGTH AND ENDURANCE.

ERIC Educational Resources Information Center

BURNHAM, STAN; MCCRAW, LYNN W.

A STUDY WAS CONCERNED WITH A COMPARISON OF ISOTONIC, ISOMETRIC, AND SPEED EXERCISE PROGRAMS AS A MEANS OF DEVELOPING MUSCLE STRENGTH, ENDURANCE, SPEED, AND POWER. SUBJECTS FOR THE INVESTIGATION WERE 93 FRESHMEN AND SOPHOMORE MEN ENROLLED IN A PHYSICAL EDUCATION CLASS. AFTER MEASUREMENT OF INITIAL STATUS IN THE ATTRIBUTES UNDER CONSIDERATION, THE…

Verbal Knowledge, Working Memory, and Processing Speed as Predictors of Verbal Learning in Older Adults

ERIC Educational Resources Information Center

Rast, Philippe

2011-01-01

The present study aimed at modeling individual differences in a verbal learning task by means of a latent structured growth curve approach based on an exponential function that yielded 3 parameters: initial recall, learning rate, and asymptotic performance. Three cognitive variables--speed of information processing, verbal knowledge, working…

Initial speed of knots in the plasma tail of C/2013 R1(Lovejoy)

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

Yagi, Masafumi; Furusho, Reiko; Terai, Tsuyoshi

We report short-time variations in the plasma tail of C/2013 R1(Lovejoy). A series of short (2–3 minutes) exposure images with the 8.2 m Subaru telescope shows faint details of filaments and their motions over a 24 minute observing duration. We identified rapid movements of two knots in the plasma tail near the nucleus (∼3×10{sup 5} km). Their speeds are 20 and 25 km s{sup −1} along the tail and 3.8 and 2.2 km s{sup −1} across it, respectively. These measurements set a constraint on an acceleration model of plasma tail and knots as they set the initial speed just aftermore » their formation. We also found a rapid narrowing of the tail. After correcting the motion along the tail, the narrowing speed is estimated to be ∼8 km s{sup −1}. These rapid motions suggest the need for high time-resolution studies of comet plasma tails with a large telescope.« less

Performance of fuel system at different diesel temperature

NASA Astrophysics Data System (ADS)

Xu, Xiaoyong; Li, Xiaolu; Sun, Zai

2010-08-01

This paper presents the findings about performance of the fuel system of a diesel engine at different diesel temperature obtained through simulation and experiment. It can be seen from these findings that at the same rotational speed of fuel pump, the initial pressure in the fuel pipe remain unchanged as the fuel temperature increases, the peak pressure at the side of fuel pipe near the injector delays, and its largest value of pressure decreases. Meanwhile, at the same temperature, as the rotational speed increases, the initial pressure of fuel pipe is also essentially the same, the arrival of its peaks delays, and its largest value of pressure increases. The maximum fuel pressure at the side of fuel pipe near the injector has an increase of 28.9 %, 22.3%, and 13.9% respectively than the previous ones according to its conditions. At the same rotational speed, as the temperature increases, the injection quantity through the nozzle orifice decreases. At the same temperature, as the rotational speed increases, the injection quantity through the nozzle orifice increases. These experimental results are consistent with simulation results.

Self-similar space-time evolution of an initial density discontinuity

NASA Astrophysics Data System (ADS)

Rekaa, V. L.; Pécseli, H. L.; Trulsen, J. K.

2013-07-01

The space-time evolution of an initial step-like plasma density variation is studied. We give particular attention to formulate the problem in a way that opens for the possibility of realizing the conditions experimentally. After a short transient time interval of the order of the electron plasma period, the solution is self-similar as illustrated by a video where the space-time evolution is reduced to be a function of the ratio x/t. Solutions of this form are usually found for problems without characteristic length and time scales, in our case the quasi-neutral limit. By introducing ion collisions with neutrals into the numerical analysis, we introduce a length scale, the collisional mean free path. We study the breakdown of the self-similarity of the solution as the mean free path is made shorter than the system length. Analytical results are presented for charge exchange collisions, demonstrating a short time collisionless evolution with an ensuing long time diffusive relaxation of the initial perturbation. For large times, we find a diffusion equation as the limiting analytical form for a charge-exchange collisional plasma, with a diffusion coefficient defined as the square of the ion sound speed divided by the (constant) ion collision frequency. The ion-neutral collision frequency acts as a parameter that allows a collisionless result to be obtained in one limit, while the solution of a diffusion equation is recovered in the opposite limit of large collision frequencies.

Analysis-test correlation of airbag impact for Mars landing

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

Salama, M.; Davis, G.; Kuo, C.P.

1994-12-31

The NASA Mars Pathfinder mission is intended to demonstrate key low cost technologies for use in future science missions to Mars. Among these technologies is the landing system. Upon entering in Martian atmosphere at about 7000 m/sec., the spacecraft will deploy a series of breaking devices (parachute and solid rockets) to slow down its speed to less than 20 m/sec. as it impacts with the Martian ground. To cushion science instruments form the landing impact, an airbag system is inflated to surround the lander approximately five seconds before impact. After multiple bounces, the lander/airbags comes to rest, the airbags aremore » deflated and retracted, and the lander opens up its petals to allow a microrover to begin exploration. Of interest here, is the final landing phase. Specifically, this paper will focus on the methodology used to simulate the nonlinear dynamics of lander/airbags landing impact, and how this simulation correlates with initial tests.« less

Relativistic Gas Drag on Dust Grains and Implications

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

Hoang, Thiem, E-mail: thiemhoang@kasi.re.kr; Korea University of Science and Technology, Daejeon, 34113

We study the drag force on grains moving at relativistic velocities through interstellar gas and explore its application. First, we derive a new analytical formula of the drag force at high energies and find that it is significantly reduced compared to the classical model. Second, we apply the obtained drag force to calculate the terminal velocities of interstellar grains by strong radiation sources such as supernovae and active galactic nuclei (AGNs). We find that grains can be accelerated to relativistic velocities by very luminous AGNs. We then quantify the deceleration of relativistic spacecraft proposed by the Breakthrough Starshot initiative duemore » to gas drag on a relativistic lightsail. We find that the spacecraft’s decrease in speed is negligible because of the suppression of gas drag at relativistic velocities, suggesting that the lightsail may be open for communication during its journey to α Centauri without causing a considerable delay. Finally, we show that the damage to relativistic thin lightsails by interstellar dust is a minor effect.« less

Use of regionalisation approach to develop fire frequency curves for Victoria, Australia

NASA Astrophysics Data System (ADS)

Khastagir, Anirban; Jayasuriya, Niranjali; Bhuyian, Muhammed A.

2017-11-01

It is important to perform fire frequency analysis to obtain fire frequency curves (FFC) based on fire intensity at different parts of Victoria. In this paper fire frequency curves (FFCs) were derived based on forest fire danger index (FFDI). FFDI is a measure related to fire initiation, spreading speed and containment difficulty. The mean temperature (T), relative humidity (RH) and areal extent of open water (LC2) during summer months (Dec-Feb) were identified as the most important parameters for assessing the risk of occurrence of bushfire. Based on these parameters, Andrews' curve equation was applied to 40 selected meteorological stations to identify homogenous stations to form unique clusters. A methodology using peak FFDI from cluster averaged FFDIs was developed by applying Log Pearson Type III (LPIII) distribution to generate FFCs. A total of nine homogeneous clusters across Victoria were identified, and subsequently their FFC's were developed in order to estimate the regionalised fire occurrence characteristics.

A One-Hand Nut and Bolt Assembly Tool

NASA Technical Reports Server (NTRS)

Spencer, J. M.

1984-01-01

Special wrench speeds nut and bolt assembly when insufficient room to hold nut behind bolthole with standard tool. C-clamp shaped box-andsocket-wrench assembly holds nut on blind side in alinement to receive bolt from open side.

Open Rotor Research at NASA Glenn

NASA Technical Reports Server (NTRS)

VanZante, Dale E.

2011-01-01

A low-noise open rotor system is being tested in collaboration with General Electric and CFM International, a 50/50 joint company between Snecma and GE. Candidate technologies for lower noise will be investigated as well as installation effects such as pylon integration. The research program in both the low and high-speed wind tunnels is reviewed. Some detailed flowfield and acoustics measurements acquired for an internal NASA program are highlighted. The publically available research data is presented also.

Vision based speed breaker detection for autonomous vehicle

NASA Astrophysics Data System (ADS)

C. S., Arvind; Mishra, Ritesh; Vishal, Kumar; Gundimeda, Venugopal

2018-04-01

In this paper, we are presenting a robust and real-time, vision-based approach to detect speed breaker in urban environments for autonomous vehicle. Our method is designed to detect the speed breaker using visual inputs obtained from a camera mounted on top of a vehicle. The method performs inverse perspective mapping to generate top view of the road and segment out region of interest based on difference of Gaussian and median filter images. Furthermore, the algorithm performs RANSAC line fitting to identify the possible speed breaker candidate region. This initial guessed region via RANSAC, is validated using support vector machine. Our algorithm can detect different categories of speed breakers on cement, asphalt and interlock roads at various conditions and have achieved a recall of 0.98.

Short-Term Effects of Thoracic Spine Manipulation on the Biomechanical Organisation of Gait Initiation: A Randomized Pilot Study

PubMed Central

Ditcharles, Sébastien; Yiou, Eric; Delafontaine, Arnaud; Hamaoui, Alain

2017-01-01

Speed performance during gait initiation is known to be dependent on the capacity of the central nervous system to generate efficient anticipatory postural adjustments (APA). According to the posturo-kinetic capacity (PKC) concept, any factor enhancing postural chain mobility and especially spine mobility, may facilitate the development of APA and thus speed performance. “Spinal Manipulative Therapy High-Velocity, Low-Amplitude” (SMT-HVLA) is a healing technique applied to the spine which is routinely used by healthcare practitioners to improve spine mobility. As such, it may have a positive effect on the PKC and therefore facilitate gait initiation. The present study aimed to investigate the short-term effect of thoracic SMT-HVLA on spine mobility, APA and speed performance during gait initiation. Healthy young adults (n = 22) performed a series of gait initiation trials on a force plate before (“pre-manipulation” condition) and after (“post-manipulation” condition) a sham manipulation or an HVLA manipulation applied to the ninth thoracic vertebrae (T9). Participants were randomly assigned to the sham (n = 11) or the HVLA group (n = 11).The spine range of motion (ROM) was assessed in each participant immediately after the sham or HVLA manipulations using inclinometers. The results showed that the maximal thoracic flexion increased in the HVLA group after the manipulation, which was not the case in the sham group. In the HVLA group, results further showed that each of the following gait initiation variables reached a significantly lower mean value in the post-manipulation condition as compared to the pre-manipulation condition: APA duration, peak of anticipatory backward center of pressure displacement, center of gravity velocity at foot-off, mechanical efficiency of APA, peak of center of gravity velocity and step length. In contrast, for the sham group, results showed that none of the gait initiation variables significantly differed between the pre- and post-manipulation conditions. It is concluded that HVLA manipulation applied to T9 has an immediate beneficial effect on spine mobility but a detrimental effect on APA development and speed performance during gait initiation. We suggest that a neural effect induced by SMT-HVLA, possibly mediated by a transient alteration in the early sensory-motor integration, might have masked the potential mechanical benefits associated with increased spine mobility. PMID:28713254

Stagnation, circulation, and erosion of granular materials through belt conveyor sluice gate

NASA Astrophysics Data System (ADS)

Pohlman, Nicholas; Moralda, Michael; Dunne, Ryan

2013-11-01

Control of flow rates in conversion reactors for discrete materials like biomass can be achieved in belt conveyors through a combination of belt speed, hopper size, and aperture opening. As material is extracted from the bottom of the storage hopper, other material cannot achieve plug flow and therefore is restricted from exiting through a sluice-gate type opening. The excess material moves vertically from the opening causing a pile up and recirculation back along the free surface of the hopper. Experimental results obtained through high speed imaging show the position of the stagnation point as well as the rate of circulation is dependent on the mass flow rate achieved and instantaneous fill level. The movement of material into the plug flow along the belt allows verification of deposition models on erodible beds rather than rigid surfaces with artificial roughness of glued particles. Similarly, the pile-up at the exit influences the efficiency of the transport affecting the narrow energy return on investment of biomass resources. The laboratory-scale behavior can therefore be translated into industrial performance metrics for increased operational efficiency. This work is supported by the NSF REU Site Operation E-Tank under award number 1156789.

Low-speed aerodynamic test of an axisymmetric supersonic inlet with variable cowl slot

NASA Technical Reports Server (NTRS)

Powell, A. G.; Welge, H. R.; Trefny, C. J.

1985-01-01

The experimental low-speed aerodynamic characteristics of an axisymmetric mixed-compression supersonic inlet with variable cowl slot are described. The model consisted of the NASA P-inlet centerbody and redesigned cowl with variable cowl slot powered by the JT8D single-stage fan simulator and driven by an air turbine. The model was tested in the NASA Lewis Research Center 9- by 15-foot low-speed tunnel at Mach numbers of 0, 0.1, and 0.2 over a range of flows, cowl slot openings, centerbody positions, and angles of attack. The variable cowl slot was effective in minimizing lip separation at high velocity ratios, showed good steady-state and dynamic distortion characteristics, and had good angle-of-attack tolerance.

Modelling and Control of an Annular Momentum Control Device

NASA Technical Reports Server (NTRS)

Downer, James R.; Johnson, Bruce G.

1988-01-01

The results of a modelling and control study for an advanced momentum storage device supported on magnetic bearings are documented. The control challenge posed by this device lies in its dynamics being such a strong function of flywheel rotational speed. At high rotational speed, this can lead to open loop instabilities, resulting in requirements for minimum and maximum control bandwidths and gains for the stabilizing controllers. Using recently developed analysis tools for systems described by complex coefficient differential equations, the closed properties of the controllers were analyzed and stability properties established. Various feedback controllers are investigated and discussed. Both translational and angular dynamics compensators are developed, and measures of system stability and robustness to plant and operational speed variations are presented.

Runaway transient simulation of a model Kaplan turbine

NASA Astrophysics Data System (ADS)

Liu, S.; Zhou, D.; Liu, D.; Wu, Y.; Nishi, M.

2010-08-01

The runaway transient is a typical transient process of a hydro power unit, where the rotational speed of a turbine runner rapidly increases up to the runaway speed under a working head as the guide vanes cannot be closed due to some reason at the load rejection. In the present paper, the characteristics of the runaway transient of a model Kaplan turbine having ns = 479(m-kW) is simulated by using a time-dependent CFD technique where equation of rotational motion of runner, continuity equation and unsteady RANS equations with RNG k-epsilon turbulence model are solved iteratively. In the calculation, unstructured mesh is used to the whole flow passage, which consists of several sub-domains: entrance, casing, stay vanes + guide vanes, guide section, runner and draft tube. And variable speed sliding mesh technique is used to exchange interface flow information between moving part and stationary part, and three-dimensional unstructured dynamic mesh technique is also adopted to ensure mesh quality. Two cases were treated in the simulation of runaway transient characteristics after load rejection: one is the rated operating condition as the initial condition, and the other is the condition at the maximum head. Regarding the runaway speed, the experimental speed is 1.45 times the initial speed and the calculation is 1.47 times the initial for the former case. In the latter case, the experiment and the calculation are 1.67 times and 1.69 times respectively. From these results, it is recognized that satisfactorily prediction will be possible by using the present numerical method. Further, numerical results show that the swirl in the draft-tube flow becomes stronger in the latter part of the transient process so that a vortex rope will occur in the draft tube and its precession will cause the pressure fluctuations which sometimes affect the stability of hydro power system considerably.

Analysis of the acceleration profile according to initial speed and positional role in elite professional male soccer players.

PubMed

de Hoyo, Moisés; Sañudo, Borja; Suárez-Arrones, Luis; Carrasco, Luis; Joel, Tom; Domínguez-Cobo, Sergio; Núñez, Francisco J

2017-12-01

The aim of the current study was to analyse the acceleration profile in elite professional soccer players according to their initial speed but also considering players' position. Players' accelerations profiles were analysed using a relative acceleration profile according to the initial speed (S1, from 0 to 7 km/h; S2, from 7.1 to 14.3 km/h; and S3, ≥14.4 km/h) and the maximum acceleration. Within-group analyses showed that Center Backs (CB) performed more high intensity accelerations (likely) when they started in S1 than S2 (ES: 0.50). Strikers (S) and Wide Midfielders (W-MD) achieved more accelerations (likely to almost certain) starting in S3 than S1 (ES: 0.80 and 0.59, respectively) and S2 (ES: 0.67 and 1.09, respectively). Full Backs (FB) completed more accelerations (almost certain) starting in S1 and S3 than S2 (ES: 1.39 and 1.36, respectively). Finally, Midfielders (MD) executed a greater number of high intensity accelerations (likely to almost certain) when they started in S1 than S2 (ES: 0.83) and S3 (ES: 0.66), and in S3 than S2 (ES: 4.72). Between-group analyses showed that S, W-MD, and FB performed a greater total number of high intensity accelerations (very likely to almost certain) than CB (ES: 1.94, 1.57, and 1.51, respectively) and MD (ES: 1.23, 0.92; and 0.81, respectively). Furthermore, MD performed substantially greater total number of high intensity accelerations (likely) than CB (ES: 0.56). Results suggest that CB achieved more high-intensity accelerations starting in low and moderate speed, S and W-MD in high speed, and FB combined low and high speed.

AGT100 turbomachinery. [for automobiles

NASA Technical Reports Server (NTRS)

Tipton, D. L.; Mckain, T. F.

1982-01-01

High-performance turbomachinery components have been designed and tested for the AGT100 automotive engine. The required wide range of operation coupled with the small component size, compact packaging, and low cost of production provide significant aerodynamic challenges. Aerodynamic design and development testing of the centrifugal compressor and two radial turbines are described. The compressor achieved design flow, pressure ratio, and surge margin on the initial build. Variable inlet guide vanes have proven effective in modulating flow capacity and in improving part-speed efficiency. With optimum use of the variable inlet guide vanes, the initial efficiency goals have been demonstrated in the critical idle-to-70% gasifier speed range. The gasifier turbine exceeded initial performance goals and demonstrated good performance over a wide range. The radial power turbine achieved 'developed' efficiency goals on the first build.

Love-type wave propagation in a pre-stressed viscoelastic medium influenced by smooth moving punch

NASA Astrophysics Data System (ADS)

Singh, A. K.; Parween, Z.; Chatterjee, M.; Chattopadhyay, A.

2015-04-01

In the present paper, a mathematical model studying the effect of smooth moving semi-infinite punch on the propagation of Love-type wave in an initially stressed viscoelastic strip is developed. The dynamic stress concentration due to the punch for the force of a constant intensity has been obtained in the closed form. Method based on Weiner-hopf technique which is indicated by Matczynski has been employed. The study manifests the significant effect of various affecting parameters viz. speed of moving punch associated with Love-type wave speed, horizontal compressive/tensile initial stress, vertical compressive/tensile initial stress, frequency parameter, and viscoelastic parameter on dynamic stress concentration due to semi-infinite punch. Moreover, some important peculiarities have been traced out and depicted by means of graphs.

Timing of spring wild turkey hunting in relation to nest incubation

USGS Publications Warehouse

Casalena, Mary Jo; Everett, Rex; Vreeland, Wendy C.; Gregg, Ian D.; Diefenbach, Duane R.

2016-01-01

State wildlife agencies are often requested to open spring wild turkey (Meleagris gallopavo; hereafter, turkey) hunting seasons earlier to increase hunter satisfaction by hunters hearing more gobbling male turkeys. Timing of spring turkey hunting season in several states, including Pennsylvania, has been established to open, on average, near median date of incubation initiation of turkey nests. This is believed to reduce illegal and undesired hen harvest and possibly nest abandonment, while maintaining hunter satisfaction of hearing male turkeys when most hens are incubating eggs. However, Pennsylvania’s spring season structure was established in 1968. Given earlier spring phenology, and potentially more variation in spring weather due to climate change, there is concern that timing of nest incubation for turkeys in Pennsylvania could be changing. Therefore, our objective was to determine if nest incubation and opening of spring turkey hunting in Pennsylvania have continued to coincide. We attached satellite transmitters to 254 female turkeys during 2010–2014 and estimated median incubation initiation date to be 2 May, which was 2 days earlier than median date during a statewide study during 1953–1963 and 9 days earlier than during a smaller scale study in south–central Pennsylvania during 2000–2001. However, incubation initiation varied greatly among years and individual hens during all 3 studies. During 4 of 5 years of our study, Pennsylvania’s spring season opened 3 to 8 days prior to median date of incubation initiation. Over the 5 years, estimated initiation of incubation for first nesting attempts, measured from earliest date of incubation initiation to latest, was >2 months and maximum proportion of hens beginning incubation at any one time differed by several days to >1 week. Consequently, in years of late incubation, a constant season opening date set near the long-term median date of incubation initiation exposes few additional hens to risk and hunter satisfaction is likely maintained at greater levels than would be seen with a more conservative approach of opening the season later. Long-term and large scale studies using GPS transmitters that provide precise determination of incubation initiation will be useful to study environmental influences on initiation of incubation.

UV Raman and Fluorescence for Multi-Species Measurement in Hydrocarbon-Fueled High-Speed Propulsion

NASA Technical Reports Server (NTRS)

Skaggs, Patricia Annette; Nandula, Sastri P.; Pitz, Robert W.

1999-01-01

This report documents work performed through the NASA Graduate Student Researchers Program, Grant No. NGT3-52316. Research performed included investigation of two-line fluorescence imaging of OH for temperature measurement and an investigation of negative flame speeds for modeling of premixed turbulent flames. The laboratory work and initial analysis of the fluorescence imaging was performed at NASA Glen Research Center with follow up analysis at Vanderbilt University. The negative flame speed investigation was performed using an opposed jet flow simulation program at Vanderbilt University. The fluorescence imaging work is presented first followed by the negative flame speed investigation.

Re-Invigorating Openness at The Open University: The Role of Open Educational Resources

ERIC Educational Resources Information Center

Gourley, Brenda; Lane, Andy

2009-01-01

This paper describes the internal motivations and external drivers that led The Open University UK to enter the field of Open Educational Resources through its institution-wide OpenLearn initiative (www.open.ac.uk/openlearn). It also describes some of the emerging evidence of the impacts inside and outside the university. Through the rapid…

Cognitive inconsistency in bipolar patients is determined by increased intra-individual variability in initial phase of task performance.

PubMed

Krukow, Paweł; Szaniawska, Ola; Harciarek, Michał; Plechawska-Wójcik, Małgorzata; Jonak, Kamil

2017-03-01

Bipolar patients show high intra-individual variability during cognitive processing. However, it is not known whether there are a specific fluctuations of variability contributing to the overall high cognitive inconsistency. The objective was to compare dynamic profiles of patients and healthy controls to identify hypothetical differences and their associations with overall variability and processing speed. Changes of reaction times iSD during processing speed test performance over time was measured by dividing the iSD for whole task into four consecutive parts. Motor speed and cognitive effort were controlled. Patients with BD exhibited significantly lower results regarding processing speed and higher intra-individual variability comparing with HC. The profile of intra-individual variability changes over time of performance was significantly different in BD versus HC groups: F(3, 207)=8.60, p<0.0001, η p 2 =0.11. iSD of BD patients in the initial phase of performance was three times higher than in the last. There was no significant differences between four intervals in HC group. Inter-group difference in the initial part of the profiles was significant also after controlling for several cognitive and clinical variables. Applied computer version of Cognitive Speed Test was relatively new and, thus, replication studies are needed. Effect seen in the present study is driven mainly by the BD type I. Patients with BD exhibits problems with setting a stimulus-response association in starting phase of cognitive processing. This deficit may negatively interfere with the other cognitive functions, decreasing level of psychosocial functioning, therefore should be explored in future studies. Copyright © 2017 Elsevier B.V. All rights reserved.

A surface renewal model for unsteady-state mass transfer using the generalized Danckwerts age distribution function

PubMed Central

Horvath, Isabelle R.

2018-01-01

The recently derived steady-state generalized Danckwerts age distribution is extended to unsteady-state conditions. For three different wind speeds used by researchers on air–water heat exchange on the Heidelberg Aeolotron, calculations reveal that the distribution has a sharp peak during the initial moments, but flattens out and acquires a bell-shaped character with process time, with the time taken to attain a steady-state profile being a strong and inverse function of wind speed. With increasing wind speed, the age distribution narrows significantly, its skewness decreases and its peak becomes larger. The mean eddy renewal time increases linearly with process time initially but approaches a final steady-state value asymptotically, which decreases dramatically with increased wind speed. Using the distribution to analyse the transient absorption of a gas into a large body of liquid, assuming negligible gas-side mass-transfer resistance, estimates are made of the gas-absorption and dissolved-gas transfer coefficients for oxygen absorption in water at 25°C for the three different wind speeds. Under unsteady-state conditions, these two coefficients show an inverse behaviour, indicating a heightened accumulation of dissolved gas in the surface elements, especially during the initial moments of absorption. However, the two mass-transfer coefficients start merging together as the steady state is approached. Theoretical predictions of the steady-state mass-transfer coefficient or transfer velocity are in fair agreement (average absolute error of prediction = 18.1%) with some experimental measurements of the same for the nitrous oxide–water system at 20°C that were made in the Heidelberg Aeolotron. PMID:29892429

Return Stroke Current Reflections in Rocket-Triggered Lightning

NASA Astrophysics Data System (ADS)

Caicedo, J.; Uman, M. A.; Jordan, D.; Biagi, C. J.; Hare, B.

2015-12-01

In the six years from 2009 to 2014, there have been eight triggered flashes at the ICLRT, from a total of 125, in which a total of ten return stroke channel-base currents exhibited a dip 3.0 to 16.6 μs after the initial current peak. Close range electric field measurements show a related dip following the initial electric field peak, and electric field derivative measurements show an associated bipolar pulse, confirming that this phenomenon is not an instrumentation effect in the current measurement. For six of the eight flashes, high-speed video frames show what appears to be suspended sections of unexploded triggering wire at heights of about 150 to 300 m that are illuminated when the upward current wave reaches them. The suspended wire can act as an impedance discontinuity, perhaps as it explodes, and cause a downward reflection of some portion of the upward-propagating current wave. This reflected wave travels down the channel and causes the dip in the measured channel-base current when it reaches ground and reflects upward. The modified transmission line model with exponential decay (MTLE) is used to model the close electric field and electric field derivatives of the postulated initial and reflected current waves, starting with the measured channel base current, and the results are compared favorably with measurements made at distances ranging from 92 to 444 m. From the measured time between current impulse initiation and the time the current reflection reaches the channel base and the current dip initiates, along with the reflection height from the video records, we find the average return stroke current speed for each of the ten strokes to be from 0.28 to 1.9×108 ms-1, with an error of ±0.01×108 ms-1 due to a ±0.1 μs uncertainty in the measurement. This represents the first direct measurement of return stroke current speed, all previous return stroke speed measurements being derived from the luminosity of the process.

Relaxation Method for Navier-Stokes Equation

NASA Astrophysics Data System (ADS)

de Oliveira, P. M. C.

2012-04-01

The motivation for this work was a simple experiment [P. M. C. de Oliveira, S. Moss de Oliveira, F. A. Pereira and J. C. Sartorelli, preprint (2010), arXiv:1005.4086], where a little polystyrene ball is released falling in air. The interesting observation is a speed breaking. After an initial nearly linear time-dependence, the ball speed reaches a maximum value. After this, the speed finally decreases until its final, limit value. The provided explanation is related to the so-called von Kármán street of vortices successively formed behind the falling ball. After completely formed, the whole street extends for some hundred diameters. However, before a certain transient time needed to reach this steady-state, the street is shorter and the drag force is relatively reduced. Thus, at the beginning of the fall, a small and light ball may reach a speed superior to the sustainable steady-state value. Besides the real experiment, the numerical simulation of a related theoretical problem is also performed. A cylinder (instead of a 3D ball, thus reducing the effective dimension to 2) is positioned at rest inside a wind tunnel initially switched off. Suddenly, at t = 0 it is switched on with a constant and uniform wind velocity ěc{V} far from the cylinder and perpendicular to it. This is the first boundary condition. The second is the cylinder surface, where the wind velocity is null. In between these two boundaries, the velocity field is determined by solving the Navier-Stokes equation, as a function of time. For that, the initial condition is taken as the known Stokes laminar limit V → 0, since initially the tunnel is switched off. The numerical method adopted in this task is the object of the current text.

Analysis Method of Friction Torque and Weld Interface Temperature during Friction Process of Steel Friction Welding

NASA Astrophysics Data System (ADS)

Kimura, Masaaki; Inoue, Haruo; Kusaka, Masahiro; Kaizu, Koichi; Fuji, Akiyoshi

This paper describes an analysis method of the friction torque and weld interface temperature during the friction process for steel friction welding. The joining mechanism model of the friction welding for the wear and seizure stages was constructed from the actual joining phenomena that were obtained by the experiment. The non-steady two-dimensional heat transfer analysis for the friction process was carried out by calculation with FEM code ANSYS. The contact pressure, heat generation quantity, and friction torque during the wear stage were calculated using the coefficient of friction, which was considered as the constant value. The thermal stress was included in the contact pressure. On the other hand, those values during the seizure stage were calculated by introducing the coefficient of seizure, which depended on the seizure temperature. The relationship between the seizure temperature and the relative speed at the weld interface in the seizure stage was determined using the experimental results. In addition, the contact pressure and heat generation quantity, which depended on the relative speed of the weld interface, were solved by taking the friction pressure, the relative speed and the yield strength of the base material into the computational conditions. The calculated friction torque and weld interface temperatures of a low carbon steel joint were equal to the experimental results when friction pressures were 30 and 90 MPa, friction speed was 27.5 s-1, and weld interface diameter was 12 mm. The calculation results of the initial peak torque and the elapsed time for initial peak torque were also equal to the experimental results under the same conditions. Furthermore, the calculation results of the initial peak torque and the elapsed time for initial peak torque at various friction pressures were equal to the experimental results.

Origin of the High-speed Jets Fom Magnetic Flux Emergence in the Solar Transition Region as well as Their Mass and Energy Contribuctions to the Solar Wind

NASA Astrophysics Data System (ADS)

Liping, Y.; He, J.; Peter, H.; Tu, C. Y.; Feng, X. S.

2015-12-01

In the solar atmosphere, the jets are ubiquitous and found to be at various spatia-temporal scales. They are significant to understand energy and mass transport in the solar atmosphere. Recently, the high-speed transition region jets are reported from the observation. Here we conduct a numerical simulation to investigate the mechanism in their formation, as well as their mass and energy contributions to the solar wind. Driven by the supergranular convection motion, the magnetic reconnection between the magnetic loop and the background open flux occurring in the transition region is simulated with a two-dimensional MHD model. The simulation results show that not only a fast hot jet, much resemble the found transition region jets, but also a adjacent slow cool jet, mostly like classical spicules, is launched. The force analysis shows that the fast hot jet is continually driven by the Lorentz force around the reconnection region, while the slow cool jet is induced by an initial kick through the Lorentz force associated with the emerging magnetic flux. Also, the features of the driven jets change with the amount of the emerging magnetic flux, giving the varieties of both jets.With the developed one-dimensional hydrodynamic solar wind model, the time-dependent pulses are imposed at the bottom to simulate the jet behaviors. The simulation results show that without other energy source, the injected plasmas are accelerated effectively to be a transonic wind with a substantial mass flux. The rapid acceleration occurs close to the Sun, and the resulting asymptotic speeds, number density at 0.3 AU, as well as mass flux normalized to 1 AU are compatible with in site observations. As a result of the high speed, the imposed pulses lead to a train of shocks traveling upward. By tracing the motions of the injected plasma, it is found that these shocks heat and accelerate the injected plasma to make part of them propagate upward and eventually escape. The parametric study shows that as the speed and temperature of the imposed pulses increase, we get an increase of the speed and temperature of the driven solar wind, which do not be influenced by the increase of the number density of the imposed pulses. When the recurring period of the imposed pulses decreases, the obtained solar wind becomes slower and cooler.

40 CFR Table 8 to Subpart Wwww of... - Initial Compliance With Organic HAP Emissions Limits

Code of Federal Regulations, 2010 CFR

2010-07-01

... SOURCE CATEGORIES National Emissions Standards for Hazardous Air Pollutants: Reinforced Plastic... organic HAP emissions limit . . . You have demonstrated initial complianceif . . . 1. open molding and... contents. 2. open molding centrifugal casting, continuous lamination/casting, SMC and BMC manufacturing...

First and second order semi-Markov chains for wind speed modeling

NASA Astrophysics Data System (ADS)

Prattico, F.; Petroni, F.; D'Amico, G.

2012-04-01

The increasing interest in renewable energy leads scientific research to find a better way to recover most of the available energy. Particularly, the maximum energy recoverable from wind is equal to 59.3% of that available (Betz law) at a specific pitch angle and when the ratio between the wind speed in output and in input is equal to 1/3. The pitch angle is the angle formed between the airfoil of the blade of the wind turbine and the wind direction. Old turbine and a lot of that actually marketed, in fact, have always the same invariant geometry of the airfoil. This causes that wind turbines will work with an efficiency that is lower than 59.3%. New generation wind turbines, instead, have a system to variate the pitch angle by rotating the blades. This system able the wind turbines to recover, at different wind speed, always the maximum energy, working in Betz limit at different speed ratios. A powerful system control of the pitch angle allows the wind turbine to recover better the energy in transient regime. A good stochastic model for wind speed is then needed to help both the optimization of turbine design and to assist the system control to predict the value of the wind speed to positioning the blades quickly and correctly. The possibility to have synthetic data of wind speed is a powerful instrument to assist designer to verify the structures of the wind turbines or to estimate the energy recoverable from a specific site. To generate synthetic data, Markov chains of first or higher order are often used [1,2,3]. In particular in [3] is presented a comparison between a first-order Markov chain and a second-order Markov chain. A similar work, but only for the first-order Markov chain, is conduced by [2], presenting the probability transition matrix and comparing the energy spectral density and autocorrelation of real and synthetic wind speed data. A tentative to modeling and to join speed and direction of wind is presented in [1], by using two models, first-order Markov chain with different number of states, and Weibull distribution. All this model use Markov chains to generate synthetic wind speed time series but the search for a better model is still open. Approaching this issue, we applied new models which are generalization of Markov models. More precisely we applied semi-Markov models to generate synthetic wind speed time series. Semi-Markov processes (SMP) are a wide class of stochastic processes which generalize at the same time both Markov chains and renewal processes. Their main advantage is that of using whatever type of waiting time distribution for modeling the time to have a transition from one state to another one. This major flexibility has a price to pay: availability of data to estimate the parameters of the model which are more numerous. Data availability is not an issue in wind speed studies, therefore, semi-Markov models can be used in a statistical efficient way. In this work we present three different semi-Markov chain models: the first one is a first-order SMP where the transition probabilities from two speed states (at time Tn and Tn-1) depend on the initial state (the state at Tn-1), final state (the state at Tn) and on the waiting time (given by t=Tn-Tn-1), the second model is a second order SMP where we consider the transition probabilities as depending also on the state the wind speed was before the initial state (which is the state at Tn-2) and the last one is still a second order SMP where the transition probabilities depends on the three states at Tn-2,Tn-1 and Tn and on the waiting times t_1=Tn-1-Tn-2 and t_2=Tn-Tn-1. The three models are used to generate synthetic time series for wind speed by means of Monte Carlo simulations and the time lagged autocorrelation is used to compare statistical properties of the proposed models with those of real data and also with a time series generated though a simple Markov chain. [1] F. Youcef Ettoumi, H. Sauvageot, A.-E.-H. Adane, Statistical bivariate modeling of wind using first-order Markov chain and Weibull distribution, Renewable Energy, 28/2003 1787-1802. [2] A. Shamshad, M.A. Bawadi, W.M.W. Wan Hussin, T.A. Majid, S.A.M. Sanusi, First and second order Markov chain models for synthetic generation of wind speed time series, Energy 30/2005 693-708. [3] H. Nfaoui, H. Essiarab, A.A.M. Sayigh, A stochastic Markov chain model for simulating wind speed time series at Tangiers, Morocco, Renewable Energy 29/2004, 1407-1418.

Clinical characteristics and outcomes of fall-related open globe injuries in Japan.

PubMed

Morikawa, Shohei; Okamoto, Yoshifumi; Okamoto, Fumiki; Inomoto, Naoki; Ishikawa, Hiroto; Harimoto, Kozo; Ueda, Tetsuo; Sakamoto, Taiji; Oshika, Tetsuro

2018-07-01

To investigate the clinical characteristics and visual outcomes in patients with fall-related open globe injuries and to evaluate differences between fall-related and non-fall-related open globe injuries in Japan. A retrospective review of patients with open globe injury who presented to Japan-Clinical Research of Study (J-CREST) hospitals between 2005 and 2015 was enrolled. Clinical information including age, sex, initial visual acuity, final visual acuity, type of injury, status of the crystalline lens, zone of injury, wound length, presence of retinal detachment, proliferative vitreoretinopathy, expulsive hemorrhage, and endophthalmitis was recorded. A total of 374 eyes were enrolled, of which 120 (32.1%) suffered from fall-related injury with average age of 73.7 ± 15.9 years (range, 11-101 years). A majority of patients were female (55.8%). Of 120 patients with fall-related injury, 109 (90.8%) presented with rupture and 11 (9.2%) with laceration. A multiple regression analysis revealed that final visual acuity was significantly associated with initial visual acuity (r = 0.99, P < 0.001). Compared to non-fall-related open globe injuries, fall-related open globe injuries were associated with elderly age, female sex, poorer initial and final visual acuity, rupture, absence of the lens, larger wound size, retinal detachment, expulsive hemorrhage, and absence of endophthalmitis (P < 0.01). Fall-related open globe injuries were more frequent in elderly female and accompanied by larger wound lengths and severer ocular complications. Visual outcomes in patients with fall-related open globe injuries were related to initial visual acuity.

Multi-threading performance of Geant4, MCNP6, and PHITS Monte Carlo codes for tetrahedral-mesh geometry.

PubMed

Han, Min Cheol; Yeom, Yeon Soo; Lee, Hyun Su; Shin, Bangho; Kim, Chan Hyeong; Furuta, Takuya

2018-05-04

In this study, the multi-threading performance of the Geant4, MCNP6, and PHITS codes was evaluated as a function of the number of threads (N) and the complexity of the tetrahedral-mesh phantom. For this, three tetrahedral-mesh phantoms of varying complexity (simple, moderately complex, and highly complex) were prepared and implemented in the three different Monte Carlo codes, in photon and neutron transport simulations. Subsequently, for each case, the initialization time, calculation time, and memory usage were measured as a function of the number of threads used in the simulation. It was found that for all codes, the initialization time significantly increased with the complexity of the phantom, but not with the number of threads. Geant4 exhibited much longer initialization time than the other codes, especially for the complex phantom (MRCP). The improvement of computation speed due to the use of a multi-threaded code was calculated as the speed-up factor, the ratio of the computation speed on a multi-threaded code to the computation speed on a single-threaded code. Geant4 showed the best multi-threading performance among the codes considered in this study, with the speed-up factor almost linearly increasing with the number of threads, reaching ~30 when N  =  40. PHITS and MCNP6 showed a much smaller increase of the speed-up factor with the number of threads. For PHITS, the speed-up factors were low when N  =  40. For MCNP6, the increase of the speed-up factors was better, but they were still less than ~10 when N  =  40. As for memory usage, Geant4 was found to use more memory than the other codes. In addition, compared to that of the other codes, the memory usage of Geant4 more rapidly increased with the number of threads, reaching as high as ~74 GB when N  =  40 for the complex phantom (MRCP). It is notable that compared to that of the other codes, the memory usage of PHITS was much lower, regardless of both the complexity of the phantom and the number of threads, hardly increasing with the number of threads for the MRCP.

Direct observation of growth front movement in electron beam recrystallization of silicon layer on insulator

NASA Astrophysics Data System (ADS)

Inoue, Tomoyasu; Hamasaki, Toshihiko

1987-04-01

A high-speed movie technique was used to investigate the growth front movement during electron beam recrystallization of thin silicon layers on insulating material. In a laterally epitaxial growth process, it was clearly observed that the molten zone shape dramatically changes across a seed opening, which is due to nonuniformity in heat dissipation toward the substrate in the vicinity of the seed opening. The molten zone width and velocities of the melt front and growth front were quantitatively analyzed using digital film motion analysis. The growth front velocity was found to drastically change by ˜30% across the seed opening.

Joor Road noise level assessment.

DOT National Transportation Integrated Search

2015-07-01

Joor Road (LA 946) is an Urban 5-lane Portland cement concrete roadway with an annual daily traffic (ADT) of approximately 13,500 with 7 percent : trucks and posted speed of 55 mph. Since being opened to traffic in 2009, residents have been complaini...

78 FR 12060 - Sunshine Act Meeting; Open Commission Meeting Wednesday, February 20, 2013

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-21

... accelerate the growth and expansion of new Wi-Fi technology offering consumers faster speeds and less network congestion at Wi-Fi hot spots. The meeting site is fully accessible to people using wheelchairs or other...

Isolated Open Rotor Noise Prediction Assessment Using the F31A31 Historical Blade Set

NASA Technical Reports Server (NTRS)

Nark, Douglas M.; Jones, William T.; Boyd, D. Douglas, Jr.; Zawodny, Nikolas S.

2016-01-01

In an effort to mitigate next-generation fuel efficiency and environmental impact concerns for aviation, open rotor propulsion systems have received renewed interest. However, maintaining the high propulsive efficiency while simultaneously meeting noise goals has been one of the challenges in making open rotor propulsion a viable option. Improvements in prediction tools and design methodologies have opened the design space for next generation open rotor designs that satisfy these challenging objectives. As such, validation of aerodynamic and acoustic prediction tools has been an important aspect of open rotor research efforts. This paper describes validation efforts of a combined computational fluid dynamics and Ffowcs Williams and Hawkings equation methodology for open rotor aeroacoustic modeling. Performance and acoustic predictions were made for a benchmark open rotor blade set and compared with measurements over a range of rotor speeds and observer angles. Overall, the results indicate that the computational approach is acceptable for assessing low-noise open rotor designs. Additionally, this approach may be used to provide realistic incident source fields for acoustic shielding/scattering studies on various aircraft configurations.

Piloted Simulation Study of the Effects of High-Lift Aerodynamics on the Takeoff Noise of a Representative High-Speed Civil Transport

NASA Technical Reports Server (NTRS)

Glaab, Louis J.; Riley, Donald R.; Brandon, Jay M.; Person, Lee H., Jr.; Glaab, Patricia C.

1999-01-01

As part of an effort between NASA and private industry to reduce airport-community noise for high-speed civil transport (HSCT) concepts, a piloted simulation study was initiated for the purpose of predicting the noise reduction benefits that could result from improved low-speed high-lift aerodynamic performance for a typical HSCT configuration during takeoff and initial climb. Flight profile and engine information from the piloted simulation were coupled with the NASA Langley Aircraft Noise Prediction Program (ANOPP) to estimate jet engine noise and to propagate the resulting source noise to ground observer stations. A baseline aircraft configuration, which also incorporated different levels of projected improvements in low-speed high-lift aerodynamic performance, was simulated to investigate effects of increased lift and lift-to-drag ratio on takeoff noise levels. Simulated takeoff flights were performed with the pilots following a specified procedure in which either a single thrust cutback was performed at selected altitudes ranging from 400 to 2000 ft, or a multiple-cutback procedure was performed where thrust was reduced by a two-step process. Results show that improved low-speed high-lift aerodynamic performance provides at least a 4 to 6 dB reduction in effective perceived noise level at the FAA downrange flyover measurement station for either cutback procedure. However, improved low-speed high-lift aerodynamic performance reduced maximum sideline noise levels only when using the multiple-cutback procedures.

rhoCentralRfFoam: An OpenFOAM solver for high speed chemically active flows - Simulation of planar detonations -

NASA Astrophysics Data System (ADS)

Gutiérrez Marcantoni, L. F.; Tamagno, J.; Elaskar, S.

2017-10-01

A new solver developed within the framework of OpenFOAM 2.3.0, called rhoCentralRfFoam which can be interpreted like an evolution of rhoCentralFoam, is presented. Its use, performing numerical simulations on initiation and propagation of planar detonation waves in combustible mixtures H2-Air and H2-O2-Ar, is described. Unsteady one dimensional (1D) Euler equations coupled with sources to take into account chemical activity, are numerically solved using the Kurganov, Noelle and Petrova second order scheme in a domain discretized with finite volumes. The computational code can work with any number of species and its corresponding reactions, but here it was tested with 13 chemically active species (one species inert), and 33 elementary reactions. A gaseous igniter which acts like a shock-tube driver, and powerful enough to generate a strong shock capable of triggering exothermic chemical reactions in fuel mixtures, is used to start planar detonations. The following main aspects of planar detonations are here, treated: induction time of combustible mixtures cited above and required mesh resolutions; convergence of overdriven detonations to Chapman-Jouguet states; detonation structure (ZND model); and the use of reflected shocks to determine induction times experimentally. The rhoCentralRfFoam code was verified comparing numerical results and it was validated, through analytical results and experimental data.

High degree-of-freedom dynamic manipulation

NASA Astrophysics Data System (ADS)

Murphy, Michael P.; Stephens, Benjamin; Abe, Yeuhi; Rizzi, Alfred A.

2012-06-01

The creation of high degree of freedom dynamic mobile manipulation techniques and behaviors will allow robots to accomplish difficult tasks in the field. We are investigating the use of the body and legs of legged robots to improve the strength, velocity, and workspace of an integrated manipulator to accomplish dynamic manipulation. This is an especially challenging task, as all of the degrees of freedom are active at all times, the dynamic forces generated are high, and the legged system must maintain robust balance throughout the duration of the tasks. To accomplish this goal, we are utilizing trajectory optimization techniques to generate feasible open-loop behaviors for our 28 dof quadruped robot (BigDog) by planning the trajectories in a 13 dimensional space. Covariance Matrix Adaptation techniques are utilized to optimize for several criteria such as payload capability and task completion speed while also obeying constraints such as torque and velocity limits, kinematic limits, and center of pressure location. These open-loop behaviors are then used to generate feed-forward terms, which are subsequently used online to improve tracking and maintain low controller gains. Some initial results on one of our existing balancing quadruped robots with an additional human-arm-like manipulator are demonstrated on robot hardware, including dynamic lifting and throwing of heavy objects 16.5kg cinder blocks, using motions that resemble a human athlete more than typical robotic motions. Increased payload capacity is accomplished through coordinated body motion.

Effect of initiators on synthesis of poly(L-lactide) by ring opening polymerization

NASA Astrophysics Data System (ADS)

Pholharn, D.; Srithep, Y.; Morris, J.

2017-06-01

We studied the effect of several aliphatic alcohols, including1-dodecanol, 1-octanol and methanol, as initiators on synthesis of poly(L-lactide) (PLLA) by ring opening polymerization. The reaction starts with L-lactide monomer and uses stannous octoate as catalyst. Fourier transform infrared spectroscopy and X-ray diffraction analysis verified that PLLAs were produced successfully. Weight, number average molecular weight and polydispersity index of PLLAs were measured by gel permeation chromatography. The PLLA initiated by methanol (PLLA-Meth) presented the highest molecular weight and yield percent. From differential scanning calorimetry, PLLA-Meth showed the highest melting temperature at ∼167°C, crystallization temperature at 110°C and degree of crystallinity 80%. The thermal stability was assessed by thermogravimetric analysis: this confirmed that PLLA-Meth was superior with the highest degradation temperature compared to PLLA initiated by other initiators. We concluded that methanol was the most appropriate initiator for PLLA synthesis by ring opening polymerization.

Percutaneous Trigger Finger Release: A Cost-effectiveness Analysis.

PubMed

Gancarczyk, Stephanie M; Jang, Eugene S; Swart, Eric P; Makhni, Eric C; Kadiyala, Rajendra Kumar

2016-07-01

Percutaneous trigger finger releases (TFRs) performed in the office setting are becoming more prevalent. This study compares the costs of in-hospital open TFRs, open TFRs performed in ambulatory surgical centers (ASCs), and in-office percutaneous releases. An expected-value decision-analysis model was constructed from the payer perspective to estimate total costs of the three competing treatment strategies for TFR. Model parameters were estimated based on the best available literature and were tested using multiway sensitivity analysis. Percutaneous TFR performed in the office and then, if needed, revised open TFR performed in the ASC, was the most cost-effective strategy, with an attributed cost of $603. The cost associated with an initial open TFR performed in the ASC was approximately 7% higher. Initial open TFR performed in the hospital was the least cost-effective, with an attributed cost nearly twice that of primary percutaneous TFR. An initial attempt at percutaneous TFR is more cost-effective than an open TFR. Currently, only about 5% of TFRs are performed in the office; therefore, a substantial opportunity exists for cost savings in the future. Decision model level II.

Bispectrum from open inflation

NASA Astrophysics Data System (ADS)

Sugimura, Kazuyuki; Komatsu, Eiichiro

2013-11-01

We calculate the bispectrum of primordial curvature perturbations, ζ, generated during ``open inflation.'' Inflation occurs inside a bubble nucleated via quantum tunneling from the background false vacuum state. Our universe lives inside the bubble, which can be described as a Friedmann-Lemaȋtre-Robertson-Walker (FLRW) universe with negative spatial curvature, undergoing slow-roll inflation. We pay special attention to the issue of an initial state for quantum fluctuations. A ``vacuum state'' defined by a positive-frequency mode in de Sitter space charted by open coordinates is different from the Euclidean vacuum (which is equivalent to the so-called ``Bunch-Davies vacuum'' defined by a positive-frequency mode in de Sitter space charted by flat coordinates). Quantum tunneling (bubble nucleation) then modifies the initial state away from the original Euclidean vacuum. While most of the previous study on modifications of the initial quantum state introduces, by hand, an initial time at which the quantum state is modified as well as the form of the modification, an effective initial time naturally emerges and the form is fixed by quantum tunneling in open inflation models. Therefore, open inflation enables a self-consistent computation of the effect of a modified initial state on the bispectrum. We find a term which goes as langleζk1ζk2ζk3ranglepropto1/k12k34 in the so-called squeezed configurations, k3 << k1 ≈ k2, in agreement with the previous study on modifications of the initial state. The bispectrum in the exact folded limit, e.g., k1 = k2+k3, is also enhanced and remains finite. However, these terms are exponentially suppressed when the wavelength of ζ is smaller than the curvature radius of the universe. The leading-order bispectrum is equal to the usual one from single-field slow-roll inflation; the terms specific for open inflation arise only in the sub-leading order when the wavelength of ζ is smaller than the curvature radius.

[A photo-optical observation of gallbladder motility in dogs (author's transl)].

PubMed

Kudo, N

1976-03-01

A photo-optical observation on gallbladder motility was made with the 16 mm cine-cholangiography. The subjects studied were thirty two mongrel dogs. The gallbladder was exposed by a short upper midline abdominal incision under pentothal anesthesia. Gallbladder bile was aspirated and contrast medium was given into the bladder, through a transhepatic route. The cine-cholangiography was done by an image intensifier at a speed of one frame every 2 to 4 seconds. The cinefilms taken were observed repeatedly by the screen projection at various speeds. The drawings were made by tracing the outline of the image of the gallbladder on each frame and were overlapped. Moreover, a contraction curve was made by the cholecystometry using of film motion analyzer in every case. At the same time bile flow into the duodenum was recorded to study a relationship between the gallbladder contraction and motility of the terminal common bile duct. The results obtained are as follows: 1. In a resting state any contraction of the gallbladder was not seen during 30 minutes, and a peristalsis-like movements of the neck portion was observed. However, there was not a relationship between the contraction curve of the gallbladder and the bile flow into the duodenum. 2. Immediately after giving Caerulein, the contrast medium injected into the gallbladder was rapidly discharged into the common bile duct by a peristalsis-like movement of the neck. The size of the gallbladder was markedly decreased into three fifths of the initial state three minutes after administration. At the same time contrast medium was continuously discharged into the duodenum. 3. After giving pilocarpine a marked contraction with forceful movement of the neck and body was observed, and the size of the gallbladder was decreased into three quarters ot the initial state. Bile discharge into the duodenum was markedly increased with an active open- and closing movement of the terminal common bile duct.

FOIA

Science.gov Websites

Skip to main content (Press Enter). DOD Open Government Logo DOD Open Government U.S. Department of Defense Search DOD Open Government: Home Open Government @ DoD Transparency Congressional Inquiries Cooperation Regulatory Program Initiatives FRD Declassification DARPA Open Catalog Contact Us Freedom of

A review of wave celerity in frictionless and axisymmetrical steel-lined pressure tunnels

NASA Astrophysics Data System (ADS)

Hachem, F. E.; Schleiss, A. J.

2011-02-01

Generally applicable approaches for estimating the “quasi-static”, which means without fluid-structure interaction and frequency-dependent water-hammer wave speed in steel-lined pressure tunnels are analyzed. The external constraints and assumptions of these approaches are discussed in detail. The reformulated formulas are then compared to commonly used expressions. Some special cases of wave speed calculation such as unlined pressure tunnels and open-air penstocks are investigated. The quasi-static wave speed is significantly influenced by the state of the backfill concrete and the near-field rock zone (cracked or uncracked). In the case when these two layers are cracked, the quasi-static wave speed is overestimated in between 1% and 8% compared to uncracked concrete and near-field rock layers. Depending on the stiffness of steel liner and penstock, the fluid-structure interaction leads to significant difference in wave speeds values. Compared to the quasi-static case, the fluid-structure interaction approach, applied to steel-lined tunnels, results up to 13% higher wave speed values in the high-frequency range (higher than 600 Hz) and up to 150% lower values for frequencies between 150 and 300 Hz in the considered test case.

Connecting Entrepreneurial and Action Learning in Student-Initiated New Business Ventures: The Case of SPEED

ERIC Educational Resources Information Center

Rae, David

2009-01-01

The Student Placements for Entrepreneurs in Education (SPEED) project ran in 12 higher education institutes in the UK between 2006 and 2008, providing an innovative, action learning-based route that enabled students to start new business ventures as self-started work experience, and has influenced successor programmes. The paper addresses three…

Safety of High Speed Guided Ground Transportation Systems - An Overview of Biological Effects and Mechanisms Relevant to EMF Exposures from Mass Transit and Electric Rail Systems

DOT National Transportation Integrated Search

1993-08-01

The U.S. has implemented a national initiative to develop maglev (magnetic levitation) and other high-speed rail (HSR) : systems. There are concerns for potential adverse health effects of the Extremely Lou Frequency (3-3,000 Hz) electric : and magne...

Effect of initial densities in the lattice Boltzmann model for non-ideal fluid with curved interface

NASA Astrophysics Data System (ADS)

Gong, Jiaming; Oshima, Nobuyuki

2017-06-01

The effect of initial densities in a free energy based two-phase-flow lattice Boltzmann method for non-ideal fluids with a curved interface was investigated in the present work. To investigate this effect, the initial densities in the liquid and gas phases coming from the saturation points and the equilibrium state were adopted in the simulation of a static droplet in an open and a closed system. For the purpose of simplicity and easier comparison, the closed system is fabricated by the implementation of the periodic boundary condition at the inlet and outlet of a gas channel, and the open system is fabricated by the implementation of a constant flux boundary condition at the inlet and a free-out boundary condition at the outlet of the same gas channel. By comparing the simulation results from the two types of initial densities in the open and closed systems, it is proven that the commonly used saturation initial densities setting is the reason for droplet mass and volume variation which occurred in the simulation, particularly in the open system with a constant flux boundary condition. Such problems are believed to come from the curvature effect of the surface tension and can be greatly reduced by adopting the initial densities in the two phases from equilibrium state.

42 CFR 435.1205 - Alignment with exchange initial open enrollment period.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 4 2014-10-01 2014-10-01 false Alignment with exchange initial open enrollment... Between Medicaid, CHIP, Exchanges and Other Insurance Affordability Programs § 435.1205 Alignment with... electronic interface, an electronic account transferred from another insurance affordability program. (2) For...

78 FR 44105 - Biomass Research and Development Technical Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-23

... DEPARTMENT OF ENERGY Energy Efficiency and Renewable Energy Biomass Research and Development...: Notice of open meeting. SUMMARY: This notice announces an open meeting of the Biomass Research and... to the Biomass R&D Initiative (Initiative) and also makes written recommendations to the Biomass R&D...

Aeroacoustic and Performance Simulations of a Test Scale Open Rotor

NASA Technical Reports Server (NTRS)

Claus, Russell W.

2013-01-01

This paper explores a comparison between experimental data and numerical simulations of the historical baseline F31/A31 open rotor geometry. The experimental data were obtained at the NASA Glenn Research Center s Aeroacoustic facility and include performance and noise information for a variety of flow speeds (matching take-off and cruise). The numerical simulations provide both performance and aeroacoustic results using the NUMECA s Fine-Turbo analysis code. A non-linear harmonic method is used to capture the rotor/rotor interaction.

The Reactome pathway knowledgebase

PubMed Central

Croft, David; Mundo, Antonio Fabregat; Haw, Robin; Milacic, Marija; Weiser, Joel; Wu, Guanming; Caudy, Michael; Garapati, Phani; Gillespie, Marc; Kamdar, Maulik R.; Jassal, Bijay; Jupe, Steven; Matthews, Lisa; May, Bruce; Palatnik, Stanislav; Rothfels, Karen; Shamovsky, Veronica; Song, Heeyeon; Williams, Mark; Birney, Ewan; Hermjakob, Henning; Stein, Lincoln; D'Eustachio, Peter

2014-01-01

Reactome (http://www.reactome.org) is a manually curated open-source open-data resource of human pathways and reactions. The current version 46 describes 7088 human proteins (34% of the predicted human proteome), participating in 6744 reactions based on data extracted from 15 107 research publications with PubMed links. The Reactome Web site and analysis tool set have been completely redesigned to increase speed, flexibility and user friendliness. The data model has been extended to support annotation of disease processes due to infectious agents and to mutation. PMID:24243840

The Reactome pathway knowledgebase.

PubMed

Croft, David; Mundo, Antonio Fabregat; Haw, Robin; Milacic, Marija; Weiser, Joel; Wu, Guanming; Caudy, Michael; Garapati, Phani; Gillespie, Marc; Kamdar, Maulik R; Jassal, Bijay; Jupe, Steven; Matthews, Lisa; May, Bruce; Palatnik, Stanislav; Rothfels, Karen; Shamovsky, Veronica; Song, Heeyeon; Williams, Mark; Birney, Ewan; Hermjakob, Henning; Stein, Lincoln; D'Eustachio, Peter

2014-01-01

Reactome (http://www.reactome.org) is a manually curated open-source open-data resource of human pathways and reactions. The current version 46 describes 7088 human proteins (34% of the predicted human proteome), participating in 6744 reactions based on data extracted from 15 107 research publications with PubMed links. The Reactome Web site and analysis tool set have been completely redesigned to increase speed, flexibility and user friendliness. The data model has been extended to support annotation of disease processes due to infectious agents and to mutation.

Developing a Knowledge Base for Detection of Powertrain Failures by Reversibly Seeding Engine Faults

DTIC Science & Technology

2010-08-01

output, in terms of torque, speed and heat losses, can be accurately performed. Our investigation has focused on creating faulty operating conditions...open loop case”, used to measure the engine output for a given driver demand, for instance, 100% pedal); in the other case (“ closed loop ”) engine...could be changed in nine steps ranging from completely open to fully closed . Another butterfly valve was placed at the end of the exhaust pipe before

Balancing the competing requirements of saltatorial and fossorial specialisation: burrowing costs in the spinifex hopping mouse, Notomys alexis.

PubMed

White, Craig R; Matthews, Philip G D; Seymour, Roger S

2006-06-01

Semi-fossorial animals (burrowing surface foragers) need to balance the competing morphological requirements of terrestrial and burrowing locomotion. These species rarely show the same degree of claw, forelimb and pectoral girdle structural development that fully fossorial forms (burrowing subterranean foragers) do, but nevertheless invest considerable amounts of energy in burrow systems. The compromise between terrestrial and burrowing locomotion was investigated by measuring net costs of burrowing and pedestrian transport in the spinifex hopping mouse, Notomys alexis, a species that forages in open areas in arid environments and is adapted for saltatorial locomotion. The net cost of transport by burrowing of hopping mice was found to be more expensive than for specialised fossorial species, and burrows were estimated to represent an energy investment equivalent to the terrestrial locomotion expected to be incurred in 17-100 days. A phylogenetically independent-contrasts approach revealed that morphological specialisation for burrowing was associated with low maximum running speeds in fossorial mammals and, for non-fossorial rodents and marsupials, maximum running speed was positively correlated with an index of habitat structure that ranged from arboreal to open desert. The high terrestrial speeds attainable by this semi-fossorial species by saltatory locomotion apparently outweigh the energetic savings that would be associated with burrowing specialisation.

Variations of the Organic Matter Composition in the Sea Surface Microlayer: A Comparison between Open Ocean, Coastal, and Upwelling Sites Off the Peruvian Coast

PubMed Central

Zäncker, Birthe; Bracher, Astrid; Röttgers, Rüdiger; Engel, Anja

2017-01-01

The sea surface microlayer (SML) is the thin boundary layer between the ocean and the atmosphere, making it important for air-sea exchange processes. However, little is known about what controls organic matter composition in the SML. In particular, there are only few studies available on the differences of the SML of various oceanic systems. Here, we compared the organic matter and neuston species composition in the SML and the underlying water (ULW) at 11 stations with varying distance from the coast in the Peruvian upwelling regime, a system with high emissions of climate relevant trace gases, such as N2O and CO2. In the open ocean, organic carbon, and amino acids were highly enriched in the SML compared to the ULW. The enrichment decreased at the coastal stations and vanished in the upwelling regime. At the same time, the degradation of organic matter increased from the open ocean to the upwelling stations. This suggests that in the open ocean, upward transport processes or new production of organic matter within the SML are faster than degradation processes. Phytoplankton was generally not enriched in the SML, one group though, the Trichodesmium-like TrL (possibly containing Trichodesmium), were enriched in the open ocean but not in the upwelling region indicating that they find a favorable habitat in the open ocean SML. Our data show that the SML is a distinct habitat; its composition is more similar among different systems than between SML and ULW of a single station. Generally the enrichment of organic matter is assumed to be reduced when encountering low primary production and high wind speeds. However, our study shows the highest enrichments of organic matter in the open ocean which had the lowest primary production and the highest wind speeds. PMID:29375483

Variations of the Organic Matter Composition in the Sea Surface Microlayer: A Comparison between Open Ocean, Coastal, and Upwelling Sites Off the Peruvian Coast.

PubMed

Zäncker, Birthe; Bracher, Astrid; Röttgers, Rüdiger; Engel, Anja

2017-01-01

The sea surface microlayer (SML) is the thin boundary layer between the ocean and the atmosphere, making it important for air-sea exchange processes. However, little is known about what controls organic matter composition in the SML. In particular, there are only few studies available on the differences of the SML of various oceanic systems. Here, we compared the organic matter and neuston species composition in the SML and the underlying water (ULW) at 11 stations with varying distance from the coast in the Peruvian upwelling regime, a system with high emissions of climate relevant trace gases, such as N 2 O and CO 2 . In the open ocean, organic carbon, and amino acids were highly enriched in the SML compared to the ULW. The enrichment decreased at the coastal stations and vanished in the upwelling regime. At the same time, the degradation of organic matter increased from the open ocean to the upwelling stations. This suggests that in the open ocean, upward transport processes or new production of organic matter within the SML are faster than degradation processes. Phytoplankton was generally not enriched in the SML, one group though, the Trichodesmium -like TrL (possibly containing Trichodesmium ), were enriched in the open ocean but not in the upwelling region indicating that they find a favorable habitat in the open ocean SML. Our data show that the SML is a distinct habitat; its composition is more similar among different systems than between SML and ULW of a single station. Generally the enrichment of organic matter is assumed to be reduced when encountering low primary production and high wind speeds. However, our study shows the highest enrichments of organic matter in the open ocean which had the lowest primary production and the highest wind speeds.

A survey of critical care nurses' practices and perceptions surrounding early intravenous antibiotic initiation during septic shock.

PubMed

Roberts, Russel J; Alhammad, Abdullah M; Crossley, Lindsay; Anketell, Eric; Wood, LeeAnn; Schumaker, Greg; Garpestad, Erik; Devlin, John W

2017-08-01

Delays in antibiotic administration after severe sepsis recognition increases mortality. While physician and pharmacy-related barriers to early antibiotic initiation have been well evaluated, those factors that affect the speed by which critical care nurses working in either the emergency department or the intensive care unit setting initiate antibiotic therapy remains poorly characterized. To evaluate the knowledge, practices and perceptions of critical care nurses regarding antibiotic initiation in patients with newly recognised septic shock. A validated survey was distributed to 122 critical care nurses at one 320-bed academic institution with a sepsis protocol advocating intravenous(IV) antibiotic initiation within 1hour of shock recognition. Among 100 (82%) critical care nurses responding, nearly all (98%) knew of the existence of the sepsis protocol. However, many critical care nurses stated they would optimise blood pressure [with either fluid (38%) or both fluid and a vasopressor (23%)] before antibiotic initiation. Communicated barriers to rapid antibiotic initiation included: excessive patient workload (74%), lack of awareness IV antibiotic(s) ordered (57%) or delivered (69%), need for administration of multiple non-antibiotic IV medications (54%) and no IV access (51%). Multiple nurse-related factors influence IV antibiotic(s) initiation speed and should be incorporated into sepsis quality improvement efforts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Crystallography Open Databases and Preservation: a World-wide Initiative

NASA Astrophysics Data System (ADS)

Chateigner, Daniel

In 2003, an international team of crystallographers proposed the Crystallography Open Database (COD), a fully-free collection of crystal structure data, in the aim of ensuring their preservation. With nearly 250000 entries, this database represents a large open set of data for crystallographers, academics and industrials, located at five different places world-wide, and included in Thomson-Reuters’ ISI. As a large step towards data preservation, raw data can now be uploaded along with «digested» structure files, and COD can be questioned by most of the crystallography-linked industrial software. The COD initiative work deserves several other open developments.

A Synthetic Self-Oscillating Vocal Fold Model Platform for Studying Augmentation Injection

PubMed Central

Murray, Preston R.; Thomson, Scott L.; Smith, Marshall E.

2013-01-01

Objective Design and evaluate a platform for studying the mechanical effects of augmentation injections using synthetic self-oscillating vocal fold models. Study Design Basic science. Methods Life-sized, synthetic, multi-layer, self-oscillating vocal fold models were created that simulated bowing via volumetric reduction of the body layer relative to that of a normal, unbowed model. Material properties of the layers were unchanged. Models with varying degrees of bowing were created and paired with normal models. Following initial acquisition of data (onset pressure, vibration frequency, flow rate, and high-speed image sequences), bowed models were injected with silicone that had material properties similar to those used in augmentation procedures. Three different silicone injection quantities were tested: sufficient to close the glottal gap, insufficient to close the glottal gap, and excess silicone to create convex bowing of the bowed model. The above-mentioned metrics were again taken and compared. Pre- and post-injection high-speed image sequences were acquired using a hemilarynx setup, from which medial surface dynamics were quantified. Results The models vibrated with mucosal wave-like motion and at onset pressures and frequencies typical of human phonation. The models successfully exhibited various degrees of bowing which were then mitigated by injecting filler material. The models showed general pre- to post-injection decreases in onset pressure, flow rate, and open quotient, and a corresponding increase in vibration frequency. Conclusion The model may be useful in further explorations of the mechanical consequences of augmentation injections. PMID:24476985

Hallux valgus surgery may produce early improvements in balance control: results of a cross-sectional pilot study.

PubMed

Sadra, Saba; Fleischer, Adam; Klein, Erin; Grewal, Gurtej S; Knight, Jessica; Weil, Lowell Scott; Weil, Lowell; Najafi, Bijan

2013-01-01

Hallux valgus (HV) is associated with poorer performance during gait and balance tasks and is an independent risk factor for falls in older adults. We sought to assess whether corrective HV surgery improves gait and balance. Using a cross-sectional study design, gait and static balance data were obtained from 40 adults: 19 patients with HV only (preoperative group), 10 patients who recently underwent successful HV surgery (postoperative group), and 11 control participants. Assessments were made in the clinic using body-worn sensors. Patients in the preoperative group generally demonstrated poorer static balance control compared with the other two groups. Despite similar age and body mass index, postoperative patients exhibited 29% and 63% less center of mass sway than preoperative patients during double-and single-support balance assessments, respectively (analysis of variance P =.17 and P =.14, respectively [both eyes open condition]). Overall, gait performance was similar among the groups, except for speed during gait initiation, where lower speeds were encountered in the postoperative group compared with the preoperative group (Scheffe P = .049). This study provides supportive evidence regarding the benefits of corrective lower-extremity surgery on certain aspects of balance control. Patients seem to demonstrate early improvements in static balance after corrective HV surgery, whereas gait improvements may require a longer recovery time. Further research using a longitudinal study design and a larger sample size capable of assessing the long-term effects of HV surgical correction on balance and gait is probably warranted.

18 CFR 157.36 - Open seasons for expansions.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Open seasons for... GAS ACT Open Seasons for Alaska Natural Gas Transportation Projects § 157.36 Open seasons for expansions. Any open season for capacity exceeding the initial capacity of an Alaska natural gas...

18 CFR 157.36 - Open seasons for expansions.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Open seasons for... GAS ACT Open Seasons for Alaska Natural Gas Transportation Projects § 157.36 Open seasons for expansions. Any open season for capacity exceeding the initial capacity of an Alaska natural gas...

18 CFR 157.36 - Open seasons for expansions.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Open seasons for... GAS ACT Open Seasons for Alaska Natural Gas Transportation Projects § 157.36 Open seasons for expansions. Any open season for capacity exceeding the initial capacity of an Alaska natural gas...

18 CFR 157.36 - Open seasons for expansions.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Open seasons for... GAS ACT Open Seasons for Alaska Natural Gas Transportation Projects § 157.36 Open seasons for expansions. Any open season for capacity exceeding the initial capacity of an Alaska natural gas...

18 CFR 157.36 - Open seasons for expansions.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Open seasons for... GAS ACT Open Seasons for Alaska Natural Gas Transportation Projects § 157.36 Open seasons for expansions. Any open season for capacity exceeding the initial capacity of an Alaska natural gas...

Identification of a keratinase-producing bacterial strain and enzymatic study for its improvement on shrink resistance and tensile strength of wool- and polyester-blended fabric.

PubMed

Cai, Shao-Bo; Huang, Zheng-Hua; Zhang, Xing-Qun; Cao, Zhang-Jun; Zhou, Mei-Hua; Hong, Feng

2011-01-01

A wool-degrading bacterium was isolated from decomposition wool fabrics in China. The strain, named 3096-4, showed excellent capability of removing cuticle layer of wool fibers, as demonstrated by removing cuticle layer completely within 48 h. According to the phenotypic characteristics and 16S rRNA profile, the isolate was classified as Pseudomonas. Bacteria growth and keratinase activity of the isolate were determined during cultivation on raw wool at different temperatures, initial pH, and rotation speed using orthogonal matrix method. Maximum growth and keratinase activity of the bacterium were observed under the condition including 30 °C, initial pH 7.6, and rotational speeds 160 rpm. The keratinase-containing crude enzyme prepared from 3096-4 was evaluated in the treatment of wool fabrics. The optimal condition of our enzymatic improvement of shrink resistance was the combination of 30 °C, initial pH 7.6, and rotation speeds 160 rpm. After the optimized treatment, the wool fabrics felting shrink was 4.1% at 6 h, and textile strength was not lost.

Boron removal and its concentration in aqueous solution through progressive freeze concentration.

PubMed

Wang, Li Pang

2017-09-01

This study explored the feasibility of progressive freeze concentration in boron removal and its concentration in aqueous solution. The influence of three key parameters in progressive freeze concentration on boron removal and concentration, namely, the advance speed of the ice front, the circumferential velocity of the stirrer, and the initial boron concentration, are investigated by conducting batch experiments. The results show that the effectiveness of boron removal increases with a lower advance speed of the ice front, a higher circumferential velocity of the stirrer, and a lower initial boron concentration. For a model boron solution with an initial concentration of 100 mg/L, the boron concentration in the ice phase after progressive freeze concentration is below 1 mg/L when the advance speed of the ice front is lower than 1 cm/h and the circumferential velocity of the stirrer is higher than 0.12 m/s. In addition, the concentration of boron in the liquid phase occurs simultaneously with progressive freeze concentration. Furthermore, the results also suggest that this method can be applied to the purification and concentration of not only organic molecules but also inorganic ions.

High speed imaging for assessment of impact damage in natural fibre biocomposites

NASA Astrophysics Data System (ADS)

Ramakrishnan, Karthik Ram; Corn, Stephane; Le Moigne, Nicolas; Ienny, Patrick; Leger, Romain; Slangen, Pierre R.

2017-06-01

The use of Digital Image Correlation has been generally limited to the estimation of mechanical properties and fracture behaviour at low to moderate strain rates. High speed cameras dedicated to ballistic testing are often used to measure the initial and residual velocities of the projectile but rarely for damage assessment. The evaluation of impact damage is frequently achieved post-impact using visual inspection, ultrasonic C-scan or other NDI methods. Ultra-high speed cameras and developments in image processing have made possible the measurement of surface deformations and stresses in real time during dynamic cracking. In this paper, a method is presented to correlate the force- displacement data from the sensors to the slow motion tracking of the transient failure cracks using real-time high speed imaging. Natural fibre reinforced composites made of flax fibres and polypropylene matrix was chosen for the study. The creation of macro-cracks during the impact results in the loss of stiffness and a corresponding drop in the force history. However, optical instrumentation shows that the initiation of damage is not always evident and so the assessment of damage requires the use of a local approach. Digital Image Correlation is used to study the strain history of the composite and to identify the initiation and progression of damage. The effect of fly-speckled texture on strain measurement by image correlation is also studied. The developed method can be used for the evaluation of impact damage for different composite materials.

A genetic dissection of the photophobic response of Paramecium tetraurelia.

PubMed

Hinrichsen, Robert; Peters, Christian

2013-05-01

Paramecium tetraurelia displayed two behavioral responses upon the initiation of a light stimulus at 7 x 10(4) lux. The cells exhibited a photophobic response in the form of behavioral avoiding reactions, followed by an increase in forward swimming velocity that was significantly higher than prior to the light stimulus activation. It was determined that an intensity of approximately 6.5 x 10(3) lux was required to initiate a moderate avoidance behavioral response. Following the avoiding response, a gradual increase in speed occurred as the intensity increased, indicating that increased swimming speeds are dependent on the light intensity. Two mutants, pawnA and Dancer, were utilized since they affect known Ca(2+)-currents of the cell. The use of pawnA cells, which lack voltage-dependent Ca(2+) channel activity, showed that the two responses to light could be genetically separated, in that the cells showed no avoiding reactions, but did increase their swimming speed. The Dancer cells, which display exaggerated Ca(2+) channel activity, exhibited similar initial avoiding responses as the wild type cells, however did not increase their swimming speed as the intensity of the light was increased. This phenotype as replicated in wildtype cells that had been placed in 25 μM 8-Br-cGMP. These data demonstrate that the photophobic light response of Paramecium tetraurelia can be genetically dissected as a means of elucidating the molecular mechanisms of the light response. Copyright © 2013 Elsevier GmbH. All rights reserved.

The interaction of Bayesian priors and sensory data and its neural circuit implementation in visually-guided movement

PubMed Central

Yang, Jin; Lee, Joonyeol; Lisberger, Stephen G.

2012-01-01

Sensory-motor behavior results from a complex interaction of noisy sensory data with priors based on recent experience. By varying the stimulus form and contrast for the initiation of smooth pursuit eye movements in monkeys, we show that visual motion inputs compete with two independent priors: one prior biases eye speed toward zero; the other prior attracts eye direction according to the past several days’ history of target directions. The priors bias the speed and direction of the initiation of pursuit for the weak sensory data provided by the motion of a low-contrast sine wave grating. However, the priors have relatively little effect on pursuit speed and direction when the visual stimulus arises from the coherent motion of a high-contrast patch of dots. For any given stimulus form, the mean and variance of eye speed co-vary in the initiation of pursuit, as expected for signal-dependent noise. This relationship suggests that pursuit implements a trade-off between movement accuracy and variation, reducing both when the sensory signals are noisy. The tradeoff is implemented as a competition of sensory data and priors that follows the rules of Bayesian estimation. Computer simulations show that the priors can be understood as direction specific control of the strength of visual-motor transmission, and can be implemented in a neural-network model that makes testable predictions about the population response in the smooth eye movement region of the frontal eye fields. PMID:23223286

Airplane tracking documents the fastest flight speeds recorded for bats.

PubMed

McCracken, Gary F; Safi, Kamran; Kunz, Thomas H; Dechmann, Dina K N; Swartz, Sharon M; Wikelski, Martin

2016-11-01

The performance capabilities of flying animals reflect the interplay of biomechanical and physiological constraints and evolutionary innovation. Of the two extant groups of vertebrates that are capable of powered flight, birds are thought to fly more efficiently and faster than bats. However, fast-flying bat species that are adapted for flight in open airspace are similar in wing shape and appear to be similar in flight dynamics to fast-flying birds that exploit the same aerial niche. Here, we investigate flight behaviour in seven free-flying Brazilian free-tailed bats ( Tadarida brasiliensis ) and report that the maximum ground speeds achieved exceed speeds previously documented for any bat. Regional wind modelling indicates that bats adjusted flight speeds in response to winds by flying more slowly as wind support increased and flying faster when confronted with crosswinds, as demonstrated for insects, birds and other bats. Increased frequency of pauses in wing beats at faster speeds suggests that flap-gliding assists the bats' rapid flight. Our results suggest that flight performance in bats has been underappreciated and that functional differences in the flight abilities of birds and bats require re-evaluation.

An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology.

PubMed

Espinoza, Karlos; Valera, Diego L; Torres, José A; López, Alejandro; Molina-Aiz, Francisco D

2015-08-12

Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides precision and speed of measurement, as well as efficient data processing in low-speed wind tunnel experiments for greenhouse engineering applications. The system is based on an algorithm that identifies the system model and calculates the optimum PI controller. The validation of the system was performed on a cellulose evaporative cooling pad and on insect-proof screens to assess its response to perturbations. The control system provided an accuracy of <0.06 m·s(-1) for airflow speed and <0.50 Pa for pressure drop, thus permitting the reproducibility and standardization of the tests. The proposed control system also incorporates a fully-integrated software unit that manages the tests in terms of airflow speed and pressure drop set points.

High-speed and on-chip graphene blackbody emitters for optical communications by remote heat transfer.

PubMed

Miyoshi, Yusuke; Fukazawa, Yusuke; Amasaka, Yuya; Reckmann, Robin; Yokoi, Tomoya; Ishida, Kazuki; Kawahara, Kenji; Ago, Hiroki; Maki, Hideyuki

2018-03-29

High-speed light emitters integrated on silicon chips can enable novel architectures for silicon-based optoelectronics, such as on-chip optical interconnects, and silicon photonics. However, conventional light sources based on compound semiconductors face major challenges for their integration with a silicon-based platform because of their difficulty of direct growth on a silicon substrate. Here we report ultra-high-speed (100-ps response time), highly integrated graphene-based on-silicon-chip blackbody emitters in the near-infrared region including telecommunication wavelength. Their emission responses are strongly affected by the graphene contact with the substrate depending on the number of graphene layers. The ultra-high-speed emission can be understood by remote quantum thermal transport via surface polar phonons of the substrates. We demonstrated real-time optical communications, integrated two-dimensional array emitters, capped emitters operable in air, and the direct coupling of optical fibers to the emitters. These emitters can open new routes to on-Si-chip, small footprint, and high-speed emitters for highly integrated optoelectronics and silicon photonics.

Experimental Investigation of the Resistance Performance and Heave and Pitch Motions of Ice-Going Container Ship Under Pack Ice Conditions

NASA Astrophysics Data System (ADS)

Guo, Chun-yu; Xie, Chang; Zhang, Jin-zhao; Wang, Shuai; Zhao, Da-gang

2018-04-01

In order to analyze the ice-going ship's performance under the pack ice conditions, synthetic ice was introduced into a towing tank. A barrier using floating cylinder in the towing tank was designed to carry out the resistance experiment. The test results indicated that the encountering frequency between the ship model and the pack ice shifts towards a high-velocity point as the concentration of the pack ice increases, and this encountering frequency creates an unstable region of the resistance, and the unstable region shifts to the higher speed with the increasing concentration. The results also showed that for the same speed points, the ratio of the pack ice resistance to the open water resistance increases with the increasing concentration, and for the same concentrations, this ratio decreases as the speed increases. Motion characteristics showed that the mean value of the heave motion increases as the speed increases, and the pitch motion tends to increase with the increasing speed. In addition, the total resistance of the fullscale was predicted.

Vapour pressure and adiabatic cooling from champagne: slow-motion visualization of gas thermodynamics

NASA Astrophysics Data System (ADS)

Vollmer, Michael; Möllmann, Klaus-Peter

2012-09-01

We present two simple demonstration experiments recorded with high-speed cameras in the fields of gas dynamics and thermal physics. The experiments feature vapour pressure effects as well as adiabatic cooling observed upon opening a bottle of champagne.

Open Access Initiatives in Africa--Structure, Incentives and Disincentives

ERIC Educational Resources Information Center

Nwagwu, Williams E.

2013-01-01

Building open access in Africa is imperative not only for African scholars and researchers doing scientific research but also for the expansion of the global science and technology knowledgebase. This paper examines the structure of homegrown initiatives, and observes very low level of awareness prevailing in the higher educational institutions…

Strategic Implementation of Open Educational Resources in Higher Education Institutions

ERIC Educational Resources Information Center

Jung, Eulho; Bauer, Christine; Heaps, Allan

2017-01-01

Higher education institutions have been playing a pivotal role in the emergence and elaboration of the Open Educational Resources (OER) movement. Initially, pioneering institutions such as the Massachusetts Institute of Technology (MIT) have led the conceptualization of OER, providing models of sustainable initiatives. Following the forerunners,…

Community College Selective Enrollment and the Challenge to Open Access

ERIC Educational Resources Information Center

Morris, David Brian

2012-01-01

The open access mission is central to the community college role and mission in higher education. Although initially implemented by four-year colleges and universities, adoption of formal enrollment management initiatives in community colleges is on the increase. Admission, matriculation, retention, and persistence are affected by enrollment…

40 CFR Table 8 to Subpart Wwww of... - Initial Compliance With Organic HAP Emissions Limits

Code of Federal Regulations, 2011 CFR

2011-07-01

... organic HAP emissions limit . . . You have demonstrated initial complianceif . . . 1. open molding and... contents. 2. open molding centrifugal casting, continuous lamination/casting, SMC and BMC manufacturing... die injection, and/or wet-area enclosures that meet the criteria of § 63.5830. 6. pultrusion...

The Open Learning Initiative: New Directions for Higher Education.

ERIC Educational Resources Information Center

King, Bruce

This paper describes the Australian Open Learning Initiative (OLI), a program to facilitate access to postsecondary education. The program will provide off-campus or distance education courses for which there is evident high demand. Program features include an independent brokering agency, coordination by a university or group of universities,…

A Brief Study of the Speed Reduction of Overtaking Airplanes by Means of Air Brakes, Special Report

NASA Technical Reports Server (NTRS)

Pearson, H. A.; Amderspm. R. F.

1942-01-01

As an aid to airplane designers interested in providing pursuit airplanes with decelerating devices intended to increase the firing time when overtaking another airplane, formulas are given relating the pertinent distances and speeds in horizontal flight to the drag increase required. Charts are given for a representative parasite-drag coefficient from which the drag increase, the time gained, and the closing distance may be found. The charts are made up for three values of the ratio of the final speed of the pursuing airplane to the speed of the pursued airplane and for several values of the ratio of the speed of the pursued airplane to the initial speed of the pursuing airplane. Charts are also given indicating the drag increases obtainable with double split flaps and with conventional propellers. The use of the charts is illustrated by an example in which it is indicated that either double split flaps or, under certain ideal conditions, reversible propellers should provide the speed reductions required.

"The Open Library at AU" (Athabasca University): Supporting Open Access and Open Educational Resources

ERIC Educational Resources Information Center

Elliott, Colin; Fabbro, Elaine

2015-01-01

To address challenges that learners, course creators, librarians and academics involved with OER and MOOCs are facing when looking for scholarly materials, Athabasca University Library has initiated the development of "the Open Library at AU." This open library is a full library website that provides easy access to open and free…

Determining Level of Service for Multilane Median Opening Zone

NASA Astrophysics Data System (ADS)

Ali, Paydar; Johnnie, Ben-Edigbe

2017-08-01

The road system is a capital-intensive investment, requiring thorough schematic framework and funding. Roads are built to provide an intrinsic quality of service which satisfies the road users. Roads that provide good services are expected to deliver operational performance that is consistent with their design specifications. Level of service and cumulative percentile speed distribution methods have been used in previous studies to estimate the quality of multilane highway service. Whilst the level of service approach relies on speed/flow curve, the cumulative percentile speed distribution is based solely speed. These estimation methods were used in studies carried out in Johor Malaysia. The aim of the studies is to ascertain the extent of speed reduction caused by midblock U-turn facilities as well as verify which estimation method is more reliable. At selected sites, road segments for both directional flows were divided into free-flow and midblock zones. Traffic volume, speed and vehicle type data for each zone were collected continuously for six weeks. Both estimation methods confirmed that speed reduction would be caused by midblock u-turn facilities. However level of service methods suggested that the quality of service would improve from level F to E or D at midblock zone in spite of speed reduction. Level of service was responding to traffic volume reduction at midblock u-turn facility not travel speed reduction. The studies concluded that since level of service was more responsive to traffic volume reduction than travel speed, it cannot be solely relied upon when assessing the quality of multilane highway service.

Visualization of impact damage of composite plates by means of the Moire technique

NASA Technical Reports Server (NTRS)

Knauss, W. G.; Babcock, C. D.; Chai, H.

1980-01-01

The phenomenological aspects of propagation damage due to low velocity impact on heavily loaded graphite-epoxy composite laminates were investigated using high speed photography coupled with the moire fringe technique. High speed moire motion records of the impacted specimens are presented. The results provide information on the time scale and sequence of the failure process. While the generation of the initial damage cannot always be separated temporally from the spreading of the damage, the latter takes place on the average with a speed on the order of 200 m/sec.

Wind-tunnel measurement of noise emitted by helicopter rotors at high speed

NASA Astrophysics Data System (ADS)

Prieur, J.

Measurements of high-speed impulsive helicopter rotor noise in a wind-tunnel are presented. High-speed impulsive noise measurements have been performed in 1988 in the ONERA S2ch wind-tunnel, fitted with an acoustic lining, on two types of rotors. They show that substantial noise reduction is obtained with sweptback tips, initially designed for aerodynamic purposes, which lower transonic effects on the advancing blade tip. Emphasis is placed on the necessity of taking into account the acoustic annoyance problem, using noise prediction tools, when designing new helicopter blades.

Effect of forward speed on the roll damping of three small fishing vessels

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

Haddara, M.R.; Zhang, S.

1994-05-01

An extensive experimental program has been carried out to estimate roll damping parameters for three models of fishing vessels having different hull shapes and moving with forward speed. Roll damping parameters are determined using a novel method. This method combines the energy method and the modulating function method. The effect of forward speed, initial heel angle and the natural frequency on damping is discussed. A modification of Ikeda's formula for lift damping prediction is suggested. The modified formula produces results which are in good agreement with the experiments.

High speed cinematography of the initial break-point of latex condoms during the air burst test.

PubMed

Stube, R; Voeller, B; Davidhazy, A

1990-06-01

High speed cinematography of latex condoms inflated to burst under standard (ISO) conditions reveals that rupture of the condom typically is initiated at a small focal point on the shank of the condom and then rapidly propagates throughout the condom's surface, often ending with partial or full severance of the condom at its point of attachment to the air burst instrument. This sequence of events is the reverse of that sometimes hypothesized to occur, where initiation of burst was considered to begin at the attachment point and to constitute a testing method artifact. This hypothesis of breakage at the attachment point, if true, would diminish the value of the air burst test as a standard for assessing manufacturing quality control as well as for condom strength measurements and comparisons.

Evaluation and Windspeed Dependence of MODIS Aerosol Retrievals Over Open Ocean

NASA Technical Reports Server (NTRS)

Kleidman, Richard G.; Smirnov, Alexander; Levy, Robert C.; Mattoo, Shana; Tanre, Didier

2011-01-01

The Maritime Aerosol Network (MAN) data set provides high quality ground-truth to validate the MODIS aerosol product over open ocean. Prior validation of the ocean aerosol product has been limited to coastal and island sites. Comparing MODIS Collection 5 ocean aerosol retrieval products with collocated MAN measurements from ships shows that MODIS is meeting the pre-launch uncertainty estimates for aerosol optical depth (AOD) with 64% and 67% of retrievals at 550 nm, and 74% and 78% of retrievals at 870 nm, falling within expected uncertainty for Terra and Aqua, respectively. Angstrom Exponent comparisons show a high correlation between MODIS retrievals and shipboard measurements (R= 0.85 Terra, 0.83 Aqua), although the MODIS aerosol algorithm tends to underestimate particle size for large particles and overestimate size for small particles, as seen in earlier Collections. Prior analysis noted an offset between Terra and Aqua ocean AOD, without concluding which sensor was more accurate. The simple linear regression reported here, is consistent with other anecdotal evidence that Aqua agreement with AERONET is marginally better. However we cannot claim based on the current study that the better Aqua comparison is statistically significant. Systematic increase of error as a function of wind speed is noted in both Terra and Aqua retrievals. This wind speed dependency enters the retrieval when winds deviate from the 6 m/s value assumed in the rough ocean surface and white cap parameterizations. Wind speed dependency in the results can be mitigated by using auxiliary NCEP wind speed information in the retrieval process.