Science.gov

Sample records for high speed rail

  1. Environmental issues: noise, rail noise, and high-speed rail

    SciTech Connect

    Hall, F.L.; Welland, J.D.; Bragdon, C.R.; Houtman, J.W.; Immers, B.H.

    1987-01-01

    The six papers in the report deal with the following areas: the effect of noise barriers on the market value of adjacent residential properties; control of airport- and aircraft-related noise in the United States; a traffic-assignment model to reduce noise annoyance in urban networks; a survey of railroad occupational noise sources; a prediction procedure for rail transportation ground-borne noise and vibration; and high-speed rail in California: the dream, the process, and the reality.

  2. Chicago-St. Louis high speed rail plan

    SciTech Connect

    Stead, M.E.

    1994-12-31

    The Illinois Department of Transportation (IDOT), in cooperation with Amtrak, undertook the Chicago-St. Louis High Speed Rail Financial and Implementation Plan study in order to develop a realistic and achievable blueprint for implementation of high speed rail in the Chicago-St. Louis corridor. This report presents a summary of the Price Waterhouse Project Team`s analysis and the Financial and Implementation Plan for implementing high speed rail service in the Chicago-St. Louis corridor.

  3. Multimode nondestructive detecting method for high-speed rail defects

    NASA Astrophysics Data System (ADS)

    Sun, Mingjian; Cheng, Xingzhen; Wan, Guangnan; Liu, Ting; Fu, Ying; Wang, Yan

    2015-11-01

    It is very important to detect the surface defects of the high-speed rail for security concerns. A multimode detecting method, which integrates high resolution of optical image, high precision of photoacoustic detection and strong penetration of ultrasound detecting, is proposed for the rail defect detection. Utilizing the surface defect characteristics obtained from optical signal, the photoacoustic and ultrasound scanning region could be determined, and rail shallow and internal defect characteristics can be acquired subsequently. Eventually, fusing three modal signals mentioned above, the information of the entire rail defect, including type, extension trend and depth can be detected. It has been proved that the multimode method can improve the detecting efficiency, and enlarge the detection range in the meantime.

  4. Assessment of ultrasonic NDT methods for high speed rail inspection

    NASA Astrophysics Data System (ADS)

    Cheng, Jianzheng; Bond, Leonard J.

    2015-03-01

    This article reviews some new ultrasonic rail inspection methods emerging in recent years. It focuses on the state of the art for guided wave technologies and their potential use for used for rail inspection. It considers ultrasound transduction options including EMATs, air coupled, pulsed laser and wheel probe guided wave methods. It compares performances in terms of frequency ranges, energy delivered, ultrasonic wave modes excited, sensitivity, potential speeds of inspection, inspection regions, transducer angle and positioning. The advantages and disadvantages of each transduction modality for possible use in high speed railway are discussed. It is concluded that an EMAT and laser method, or their combination has the potential to provide a new tool for higher speed rail in-service inspection.

  5. 36 CFR 1192.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false High-speed rail cars... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including but not limited to those using “maglev” or high speed...

  6. Florida's high-speed rail and maglev projects

    SciTech Connect

    Smith, C.H. )

    1990-04-01

    The author discusses how the State of Florida has taken an innovative approach to meeting its future needs for an efficient transportation system that will complement its extensive highway network and aviation system. This new concept is a statewide, high-speed, fixed guideway ground transportation system. The technologies will include advanced electrified wheels-on-rail trains and magnetically levitated and propelled vehicles.

  7. 36 CFR 1192.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false High-speed rail cars... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including but not limited to those using “maglev” or high...

  8. 49 CFR 38.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false High-speed rail cars, monorails and systems. 38....175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including... for high-platform, level boarding and shall comply with § 38.111(a) of this part for each type of...

  9. 49 CFR 38.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false High-speed rail cars, monorails and systems. 38....175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including... for high-platform, level boarding and shall comply with § 38.111(a) of this part for each type of...

  10. 49 CFR 38.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false High-speed rail cars, monorails and systems. 38....175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including... for high-platform, level boarding and shall comply with § 38.111(a) of this part for each type of...

  11. 36 CFR 1192.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true High-speed rail cars... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including but not limited to those using “maglev” or high...

  12. 49 CFR 38.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false High-speed rail cars, monorails and systems. 38....175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including... for high-platform, level boarding and shall comply with § 38.111(a) of this part for each type of...

  13. 36 CFR 1192.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false High-speed rail cars... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including but not limited to those using “maglev” or high...

  14. 36 CFR 1192.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false High-speed rail cars... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including but not limited to those using “maglev” or high...

  15. 49 CFR 38.175 - High-speed rail cars, monorails and systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false High-speed rail cars, monorails and systems. 38....175 High-speed rail cars, monorails and systems. (a) All cars for high-speed rail systems, including... for high-platform, level boarding and shall comply with § 38.111(a) of this part for each type of...

  16. Current situation: US tests under way. [High Speed Rail Transportation

    SciTech Connect

    Not Available

    1993-04-16

    Though US high-speed rail (HSR) activity is picking up, the technology is much farther advanced in Europe and Japan. Several HSR projects have been proposed for various parts of the country, but nearly all remain in the early developmental stages. The closest equivalent to regular high-speed rail service in the US still is provided by the Amtrak Metroliners running between New York and Washington. In late January, Amtrak began a three-month trial of a Swedish-built X2000 train on the New York-Washington run. Popularly known as the [open quotes]tilt train,[close quotes] it has a computer-guided suspension system that permits higher speeds on curves. The system enables trains to bank on curves, much as racing cars do, thus minimizing the queasiness that centrifugal force can cause. Passengers report feeling little or no discomfort when the X2000 tilts.

  17. High Speed Rail (HSR) in the United States

    DTIC Science & Technology

    2009-12-08

    450,000 long-term jobs.53 48 HM Treasury and Department for Transport, The Eddington Transport Study...and Transport Research) #655, 2009, p. 13, http://www.vti.se/EPiBrowser/Publikationer%20-%20English/ R655Eng.pdf. 51 Eddington Transport Study, 2006...www.gao.gov/new.items/d09317.pdf. 56 Eddington Transport Study, 2006, p. 208. High Speed Rail (HSR) in the United States Congressional Research

  18. Proceedings: High-speed rail and maglev workshop

    SciTech Connect

    Not Available

    1993-04-01

    On October 30 and 31, 1991, the EPRI Public and Advanced Transportation Program sponsored a workshop on high-speed rail (HSR) and maglev. The purpose of this workshop was to provide utility managers with increased knowledge about these technologies, public policy regarding them, and their potential costs and benefits to utilities, including induced economic development. With this information, utilities should be better prepared to make decisions related to the development of these high speed intercity passenger options in their service areas. A main goal, achieved by the workshop, was to provide EPRI and its member utilities with ideas and information for developing an assessment and research agenda on these technologies.

  19. Outlook: Federal aid called vital. [High Speed Rail Transportation

    SciTech Connect

    Not Available

    1993-04-16

    When high speed rail (HSR) proponents survey the future of their emerging industry, they invariably pepper their forecasts with [open quotes]ifs,[close quotes] most keyed to financing. In a typical comment, Jim Betts says his agency is [open quotes]waiting for a realistic and plausible funding capability[close quotes] before starting work on the 3-C's Cleveland-Cincinnati line. Betts wants federal funding to go beyond loan guarantees or greater access to tax-exempt bonds. He favors a generous direct-subsidy formula - similar to the one that financed the Interstates - in which the federal government matched every dollar from the states with nine of its own.

  20. Track dynamic behavior at rail welds at high speed

    NASA Astrophysics Data System (ADS)

    Xiao, Guangwen; Xiao, Xinbiao; Guo, Jun; Wen, Zefeng; Jin, Xuesong

    2010-06-01

    As a vehicle passing through a track with different weld irregularities, the dynamic performance of track components is investigated in detail by using a coupled vehicle-track model. In the model, the vehicle is modeled as a multi-body system with 35 degrees of freedom, and a Timoshenko beam is used to model the rails which are discretely supported by sleepers. In the track model, the sleepers are modeled as rigid bodies accounting for their vertical, lateral and rolling motions and assumed to move backward at a constant speed to simulate the vehicle running along the track at the same speed. In the study of the coupled vehicle and track dynamics, the Hertizian contact theory and the theory proposed by Shen-Hedrick-Elkins are, respectively, used to calculate normal and creep forces between the wheel and the rails. In the calculation of the normal forces, the coefficient of the normal contact stiffness is determined by transient contact condition of the wheel and rail surface. In the calculation of the creepages, the lateral, roll-over motions of the rail and the fact that the relative velocity between the wheel and rail in their common normal direction is equal to zero are simultaneously taken into account. The motion equations of the vehicle and track are solved by means of an explicit integration method, in which the rail weld irregularities are modeled as local track vertical deviations described by some ideal cosine functions. The effects of the train speed, the axle load, the wavelength and depth of the irregularities, and the weld center position in a sleeper span on the wheel-rail impact loading are analyzed. The numerical results obtained are greatly useful in the tolerance design of welded rail profile irregularity caused by hand-grinding after rail welding and track maintenances.

  1. 78 FR 36823 - California High-Speed Rail Authority-Construction Exemption-in Merced, Madera and Fresno Counties...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-19

    ... TRANSPORTATION Surface Transportation Board California High-Speed Rail Authority--Construction Exemption--in... approval requirements of 49 U.S.C. 10901 for the California High-Speed Rail Authority (Authority) to construct an approximately 65- mile high-speed passenger rail line between Merced and Fresno,...

  2. 75 FR 32240 - Draft Tier II Environmental Impact Statement: Southeast High Speed Rail Corridor-Richmond, VA...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-07

    ... Federal Railroad Administration Draft Tier II Environmental Impact Statement: Southeast High Speed Rail... Draft Environmental Impact Statement and public hearings for the Southeast High Speed Rail, Richmond, VA... availability of the Southeast High Speed Rail, Richmond, VA to Raleigh, NC Project Draft Tier II Environmental...

  3. EPA Administrator to visit Fresno for high-speed rail groundbreaking

    EPA Pesticide Factsheets

    WASHINGTON - Tuesday, U.S. Environmental Protection Agency (EPA) Administrator Gina McCarthy will travel to Fresno, Calif. to join California Governor Jerry Brown, California High-Speed Rail Authority board members, and other government, community and tran

  4. Systems evaluation of high-speed rail for the Texas Triangle

    SciTech Connect

    Petersen, H.C.

    1985-01-01

    This dissertation describes and compares simulations of operation of different high speed rail technologies on alternative rights-of-way in the Texas Triangle which connect Dallas/Fort Worth, Houston, and San Antonio. Proposals for high speed rail on existing rights-of-way must consider geometric constraints. It was concluded that cross-sectional geometry would allow construction of a high-speed rail line along the majority of the rights-of-way. A microcomputer was used to apply the operations research technique of simulation to predict train operation over proposed routes on the Texas Triangle. The deterministic simulation program was used to investigate different types of high-speed-train technologies operating on interstate highway medians and the former Rock Island right-of-way. Results of the simulation runs demonstrated that comfort and curvature limitations prevented full utilization of speeds as high as 350 mph, and that lower speeds (around 200 mph) appear to be more appropriate, given the existing geometric constraints. The study concluded that high speed rail passenger service is technically feasible on existing rights-of-way in Texas.

  5. Life-cycle assessment of high-speed rail: the case of California

    NASA Astrophysics Data System (ADS)

    Chester, Mikhail; Horvath, Arpad

    2010-01-01

    The state of California is expected to have significant population growth in the next half-century resulting in additional passenger transportation demand. Planning for a high-speed rail system connecting San Diego, Los Angeles, San Francisco, and Sacramento as well as many population centers between is now underway. The considerable investment in California high-speed rail has been debated for some time and now includes the energy and environmental tradeoffs. The per-trip energy consumption, greenhouse gas emissions, and other emissions are often compared against the alternatives (automobiles, heavy rail, and aircraft), but typically only considering vehicle operation. An environmental life-cycle assessment of the four modes was created to compare both direct effects of vehicle operation and indirect effects from vehicle, infrastructure, and fuel components. Energy consumption, greenhouse gas emissions, and SO2, CO, NOX, VOC, and PM10 emissions were evaluated. The energy and emission intensities of each mode were normalized per passenger kilometer traveled by using high and low occupancies to illustrate the range in modal environmental performance at potential ridership levels. While high-speed rail has the potential to be the lowest energy consumer and greenhouse gas emitter, appropriate planning and continued investment would be needed to ensure sustained high occupancy. The time to environmental payback is discussed highlighting the ridership conditions where high-speed rail will or will not produce fewer environmental burdens than existing modes. Furthermore, environmental tradeoffs may occur. High-speed rail may lower energy consumption and greenhouse gas emissions per trip but can create more SO2 emissions (given the current electricity mix) leading to environmental acidification and human health issues. The significance of life-cycle inventorying is discussed as well as the potential of increasing occupancy on mass transit modes.

  6. Investigation of transient temperature's influence on damage of high-speed sliding electrical contact rail surface

    NASA Astrophysics Data System (ADS)

    Zhang, Yuyan; Sun, Shasha; Guo, Quanli; Yang, Degong; Sun, Dongtao

    2016-11-01

    In the high speed sliding electrical contact with large current, the temperature of contact area rises quickly under the coupling action of the friction heating, the Joule heating and electric arc heating. The rising temperature seriously affects the conductivity of the components and the yield strength of materials, as well affects the contact state and lead to damage, so as to shorten the service life of the contact elements. Therefore, there is vital significance to measure the temperature accurately and investigate the temperature effect on damage of rail surface. Aiming at the problem of components damage in high speed sliding electrical contact, the transient heat effect on the contact surface was explored and its influence and regularity on the sliding components damage was obtained. A kind of real-time temperature measurement method on rail surface of high speed sliding electrical contact is proposed. Under the condition of 2.5 kA current load, based on the principle of infrared radiation non-contact temperature sensor was used to measure the rail temperature. The dynamic distribution of temperature field was obtained through the simulation analysis, further, the connection between temperature changes and the rail surface damage morphology, the damage volume was analyzed and established. Finally, the method to reduce rail damage and improve the life of components by changing the temperature field was discussed.

  7. 75 FR 51331 - Draft Tier II Environmental Impact Statement: Southeast High Speed Rail Corridor-Richmond, VA...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-19

    ... Corridor--Richmond, VA (Main Street Station) to Raleigh, NC (Boylan Wye) AGENCY: Federal Railroad... the Tier II Draft Environmental Impact Statement for the Southeast High Speed Rail, Richmond, VA to... the Draft Tier II Environmental Impact Statement for the Southeast High Speed Rail, Richmond, VA...

  8. 78 FR 24309 - California High-Speed Rail Authority-Construction Exemption-in Merced, Madera and Fresno Counties...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Surface Transportation Board California High-Speed Rail Authority--Construction Exemption--in Merced, Madera and Fresno Counties, Cal On March 27, 2013, California High-Speed Rail Authority (Authority),...

  9. Modeling and simulation of high-speed passenger train movements in the rail line

    NASA Astrophysics Data System (ADS)

    Cao, Cheng-Xuan; Xu, Yan; Li, Ke-Ping

    2013-06-01

    In this paper, we propose a new formula of the real-time minimum safety headway based on the relative velocity of consecutive trains and present a dynamic model of high-speed passenger train movements in the rail line based on the proposed formula of the minimum safety headway. Moreover, we provide the control strategies of the high-speed passenger train operations based on the proposed formula of the real-time minimum safety headway and the dynamic model of high-speed passenger train movements. The simulation results demonstrate that the proposed control strategies of the passenger train operations can greatly reduce the delay propagation in the high-speed rail line when a random delay occurs.

  10. The response of a high-speed train wheel to a harmonic wheel-rail force

    NASA Astrophysics Data System (ADS)

    Sheng, Xiaozhen; Liu, Yuxia; Zhou, Xin

    2016-09-01

    The maximum speed of China's high-speed trains currently is 300km/h and expected to increase to 350-400km/h. As a wheel travels along the rail at such a high speed, it is subject to a force rotating at the same speed along its periphery. This fast moving force contains not only the axle load component, but also many components of high frequencies generated from wheel-rail interactions. Rotation of the wheel also introduces centrifugal and gyroscopic effects. How the wheel responds is fundamental to many issues, including wheel-rail contact, traction, wear and noise. In this paper, by making use of its axial symmetry, a special finite element scheme is developed for responses of a train wheel subject to a vertical and harmonic wheel-rail force. This FE scheme only requires a 2D mesh over a cross-section containing the wheel axis but includes all the effects induced by wheel rotation. Nodal displacements, as a periodic function of the cross-section angle 6, can be decomposed, using Fourier series, into a number of components at different circumferential orders. The derived FE equation is solved for each circumferential order. The sum of responses at all circumferential orders gives the actual response of the wheel.

  11. A study on high-speed rolling contact between a wheel and a contaminated rail

    NASA Astrophysics Data System (ADS)

    Zhao, Xin; Wen, Zefeng; Zhu, Minhao; Jin, Xuesong

    2014-10-01

    A 3-D explicit finite element model is developed to investigate the transient wheel-rail rolling contact in the presence of rail contamination or short low adhesion zones (LAZs). A transient analysis is required because the wheel passes by a short LAZ very quickly, especially at high speeds. A surface-to-surface contact algorithm (by the penalty method) is employed to solve the frictional rolling contact between the wheel and the rail meshed by solid elements. The LAZ is simulated by a varying coefficient of friction along the rail. Different traction efforts and action of the traction control system triggered by the LAZ are simulated by applying a time-dependent driving torque to the wheel axle. Structural flexibilities of the vehicle-track system are considered properly. Analysis focuses on the contact forces, creepage, contact stresses and the derived frictional work and plastic deformation. It is found that the longitudinal contact force and the maximum surface shear stress in the contact patch become obviously lower in the LAZ and much higher as the wheel re-enters the dry rail section. Consequently, a higher wear rate and larger plastic flow are expected at the location where the dry contact starts to be rebuilt. In other words, contact surface damages such as wheel flats and rail burns may come into being because of the LAZ. Length of the LAZ, the traction level, etc. are varied. The results also show that local contact surface damages may still occur as the traction control system acts.

  12. Inter-comparison of multi-sensor results for high-speed rail risk analysis

    NASA Astrophysics Data System (ADS)

    Hung, W.; Hwang, C.; Chang, C.; Yen, J.; Liu, C.

    2007-12-01

    The Taiwan high speed rail (THSR) is one of the most important national infrastructures. Because of its high speed, a stringent code of construction is demanded. To ensure a safe operation, the differential settlement rate of rail track should be less than 1/1000. Surface or underground subsidence will lead to failures of the foundations of rail structures and deformations of rail tracks. The effect of subsidence on the THSR structure varies with the depth of soil formation where consolidation (or groundwater withdrawal) occurs. If soil consolidation occurs above the bearing layer of the pile foundation, it will interact with the pile foundation and produce a negative skin friction, which reduces the pile bearing capacity and degrades the vertical capacity of the viaduct foundation. In the Yunlin County of Taiwan, a section of the THSR rail passes through an area undergoing significant subsidence (the current maximum rate is 10 cm/year). In an area close to the THSR, the cumulative subsidence between 1992 and 2006 is 100 cm. In order to monitor the subsidence along this section, an integrated sensor system, including INSAR, GPS, leveling and monitoring well, are deployed. INSAR will be used to map the 2-d surface deformation. Wells with observing rings at different depths are used to measure the compaction rates at various layers of strata. GPS receivers are mounted on pillars attached to the rail track to observe its vertical motion. A precision leveling network is established to measure the surface deformation. These sensors provide data revealing the surface and underground deformations around this area. This paper presents an inter- comparison of the deformations from these sensors and presents vital information for drafting a safety code for the THSR

  13. Integrated Seismic Survey for Detecting Landslide Effects on High Speed Rail Line at Istanbul-Turkey

    NASA Astrophysics Data System (ADS)

    Grit, Mert; Kanli, Ali Ismet

    2016-02-01

    In this study, Multichannel Analysis of Surface Waves Method (MASW), seismic refraction tomography and seismic reflection methods are used together at Silivri district in Istanbul - a district with a landslide problem because of the high speed rail line project crossing through the area. The landslide structure, border and depth of the slip plane are investigated and correlated within the local geology. According to the obtained 2D seismic sections, the landslide occurs through the East-West direction in the study area and the landslide slip plane with its border are clearly obtained under the subsurface. The results prove that the study area is suitable enough for the landslide development and this evolution also affects the high speed rail line project.

  14. MEDIA ADVISORY: EPA Administrator to Visit Fresno, Phoenix for high-speed rail groundbreaking, American Meteorological Society annual meeting

    EPA Pesticide Factsheets

    WASHINGTON - Today, Environmental Protection Agency (EPA) Administrator Gina McCarthy will travel to Fresno, Calif. to join California Governor Jerry Brown, California High-Speed Rail Authority board members, and other government, community and tran

  15. 78 FR 78507 - California High-Speed Rail Authority-Construction Exemption-In Fresno, Kings, Tulare, and Kern...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-26

    ..., Kings, Tulare, and Kern Counties, CA By petition filed on September 26, 2013, California High-Speed Rail... Board consider providing notice to all impacted landowners in Fresno, Kings, Tulare, and Kern...

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

    NASA Astrophysics Data System (ADS)

    Sharma, Sunil Kumar; Kumar, Anil

    2017-05-01

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

  17. High-speed rail with emerging automobiles and aircraft can reduce environmental impacts in California’s future

    NASA Astrophysics Data System (ADS)

    Chester, Mikhail; Horvath, Arpad

    2012-09-01

    Sustainable mobility policy for long-distance transportation services should consider emerging automobiles and aircraft as well as infrastructure and supply chain life-cycle effects in the assessment of new high-speed rail systems. Using the California corridor, future automobiles, high-speed rail and aircraft long-distance travel are evaluated, considering emerging fuel-efficient vehicles, new train designs and the possibility that the region will meet renewable electricity goals. An attributional per passenger-kilometer-traveled life-cycle inventory is first developed including vehicle, infrastructure and energy production components. A consequential life-cycle impact assessment is then established to evaluate existing infrastructure expansion against the construction of a new high-speed rail system. The results show that when using the life-cycle assessment framework, greenhouse gas footprints increase significantly and human health and environmental damage potentials may be dominated by indirect and supply chain components. The environmental payback is most sensitive to the number of automobile trips shifted to high-speed rail, and for greenhouse gases is likely to occur in 20-30 years. A high-speed rail system that is deployed with state-of-the-art trains, electricity that has met renewable goals, and in a configuration that endorses high ridership will provide significant environmental benefits over existing modes. Opportunities exist for reducing the long-distance transportation footprint by incentivizing large automobile trip shifts, meeting clean electricity goals and reducing material production effects.

  18. High-speed rail transportation. Hearing before the Subcommittee on Transportation and Hazardous Materials of the Committee on Energy and Commerce, US House of Representatives, One Hundred Second Congress, First Session, October 16, 1991

    SciTech Connect

    Not Available

    1991-01-01

    H.R. 1087 would authorize a high speed rail transportation development and commercialization program, establish a national high speed rail transportation policy, and promote development and commercialization of high speed rail transportation by providing Federal guarantees of certain investments in high speed rail transportation facilities. Testimony was heard from representatives of MAGLEV USA, Federal Railroad Administration, National Railroad Passenger Corporation (Amtrak), the Office of Technology Assessment, MAGLEV, Inc., National Maglev Initiative, High Speed Rail Association, and the Texas High-Speed Rail Association. Additional information was supplied by the Coalition of Northeastern Governors, Republic Locomotive, Washington State High Speed Ground Transportation, and the Texas High Speed Authority.

  19. Online Condition Monitoring of a Rail Fastening System on High-Speed Railways Based on Wavelet Packet Analysis.

    PubMed

    Wei, Jiahong; Liu, Chong; Ren, Tongqun; Liu, Haixia; Zhou, Wenjing

    2017-02-08

    The rail fastening system is an important part of a high-speed railway track. It is always critical to the operational safety and comfort of railway vehicles. Therefore, the condition detection of the rail fastening system, looseness or absence, is an important task in railway maintenance. However, the vision-based method cannot identify the severity of rail fastener looseness. In this paper, the condition of rail fastening system is monitored based on an automatic and remote-sensing measurement system. Meanwhile, wavelet packet analysis is used to analyze the acceleration signals, based on which two damage indices are developed to locate the damage position and evaluate the severity of rail fasteners looseness, respectively. To verify the effectiveness of the proposed method, an experiment is performed on a high-speed railway experimental platform. The experimental results show that the proposed method is effective to assess the condition of the rail fastening system. The monitoring system significantly reduces the inspection time and increases the efficiency of maintenance management.

  20. Online Condition Monitoring of a Rail Fastening System on High-Speed Railways Based on Wavelet Packet Analysis

    PubMed Central

    Wei, Jiahong; Liu, Chong; Ren, Tongqun; Liu, Haixia; Zhou, Wenjing

    2017-01-01

    The rail fastening system is an important part of a high-speed railway track. It is always critical to the operational safety and comfort of railway vehicles. Therefore, the condition detection of the rail fastening system, looseness or absence, is an important task in railway maintenance. However, the vision-based method cannot identify the severity of rail fastener looseness. In this paper, the condition of rail fastening system is monitored based on an automatic and remote-sensing measurement system. Meanwhile, wavelet packet analysis is used to analyze the acceleration signals, based on which two damage indices are developed to locate the damage position and evaluate the severity of rail fasteners looseness, respectively. To verify the effectiveness of the proposed method, an experiment is performed on a high-speed railway experimental platform. The experimental results show that the proposed method is effective to assess the condition of the rail fastening system. The monitoring system significantly reduces the inspection time and increases the efficiency of maintenance management. PMID:28208732

  1. High speed rail and coastal tourism: Identifying passenger profiles and travel behaviour

    PubMed Central

    Ortuño, Armando

    2017-01-01

    In this paper, we characterise tourists most likely to visit a coastal destination by high-speed rail (HSR). Our data came from a survey conducted among HSR passengers during 2014’s high season (July and August) at Spain’s Camp de Tarragona and Alicante Stations, each of which is near a mass tourism destination on the Mediterranean coast: the Costa Daurada and the Costa Blanca, respectively. We used responses to the survey, which presented binary discrete-choice situations, to construct a database necessary for a logistic regression model that allowed us to examine how passenger profile, trip characteristics, and stay conditions influenced the use of HSR services on visits to each coastal destination. Results highlighted significant differences in the profiles of tourists who arrived at each destination by HSR and, in turn, that no specific tourist profile is associated with HSR, even for two stations that serve sunny beach destinations. Among its implications, to analyse travellers that HSR can attract, it is vital to consider the specific characteristics of each destination and its current market. PMID:28644893

  2. In-service parametric modelling a rail vehicle's axle-box hydraulic damper for high-speed transit problems

    NASA Astrophysics Data System (ADS)

    Wang, W. L.; Yu, D. S.; Zhou, Z.

    2015-10-01

    Due to the high-speed operation of modern rail vehicles and severe in-service environment of their hydraulic dampers, it has become important to establish more practical and accurate damper models and apply those models in high-speed transit problem studies. An improved full parametric model with actual in-service parameters, such as variable viscous damping, comprehensive stiffness and small mounting clearance was established for a rail vehicle's axle-box hydraulic damper. A subtle variable oil property model was built and coupled to the modelling process, which included modelling of the dynamic flow losses and the relief-valve system dynamics. The experiments validated the accuracy and robustness of the established full in-service parametric model and simulation which captured the damping characteristics over an extremely wide range of excitation speeds. Further simulations were performed using the model to uncover the effects of key in-service parameter variations on the nominal damping characteristics of the damper. The obtained in-service parametric model coupled all of the main factors that had significant impacts on the damping characteristics, so that the model could be useful in more extensive parameter effects analysis, optimal specification and product design optimisation of hydraulic dampers for track-friendliness, ride comfort and other high-speed transit problems.

  3. Travel and electricity demand analysis of potential US high-speed rail and maglev corridors. Final report

    SciTech Connect

    Vyas, A.D.; Pitstick, M.E.; Rote, D.M.; Johnson, L.R.; Bernard, M.J. III

    1994-01-01

    High-speed rail (HSR) and magnetically levitated (maglev) vehicles will provide an alternative mode of transportation for intercity travel, particularly for short and medium-length trips between 100 and 600 miles (160 to 960 kilometers). A significant portion of highway and air travel can potentially be diverted to such high-speed ground transportation (HSGT) systems. Also, electric utilities will have to meet the energy demands of these systems. Because these systems require significant investments and time to construct an extensive network, they need more time for analysis and planning. This study evaluates the patterns of growth for these systems and the factors affecting that growth for the year 2010 to determine the magnitude of intercity travel, the basis for HSGT use and electricity demand. To forecast the number and frequency of intercity trips, a methodology was developed that accounts for the travelers` socioeconomic status and the attractiveness of metropolitan areas. The study revealed that aggregate travel demand relied upon population growth, the employment status of the traveler, their household size, and income. Further, the study projects travel for 78 major metropolitan areas via air and highway, and identifies the 12 highest density corridors, describing the potential for HSGT systems to substitute some of that travel. In addition, the study estimates the energy demand and power requirements for a representative high-speed rail and maglev system for each corridor and the corridor connections.

  4. The Lyon-Turin high-speed rail: the public debate and perception of environmental risk in Susa Valley, Italy.

    PubMed

    Marincioni, Fausto; Appiotti, Federica

    2009-05-01

    When the construction of the Lyon-Turin segment of the new European high-speed rail network was first publicly announced at the beginning of the 1990 s, it immediately found fierce opposition from the inhabitants of Susa Valley, Italy, one of the areas to be cut across by such infrastructure. At issue were the project's potential environmental impact and its consequences on public health. This study intends to clarify environmental risk perception and public debate between the national government, local advocacy groups, and the inhabitants of Susa Valley. Two major phases of public reaction were identified: (1) an initial rebellious period of no real dialog among the project's major stakeholders (exemplified by the popular "No TAV" [No High Speed Train] movement), followed by (2) a yielding period of intense multilateral negotiations centered on the activities of the "Lyon-Turin Environmental Observatory." The results of a qualitative cross analysis of the residents' perception of the proposed high-speed rail revealed that public acceptance of risk in Susa Valley was influenced by the characteristics of hazards perceived by the residents and by the communicative approach used by the project's various stakeholders. It also emerged that early dialog among all the parties involved was critical in forming a personal viewpoint on risk, which, once consolidated, defied new information and perspectives. Likely, a greater and earlier care taken by the other stakeholders to inform and consult the local population about the railway would have greatly eased the public debate.

  5. 75 FR 38343 - High-Speed Intercity Passenger Rail (HSIPR) Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... availability for Service Development Programs; issuance of interim program guidance. SUMMARY: This notice... passenger rail Service Development Programs available under the Transportation, Housing and Urban Development, and Related Agencies Appropriations Act for 2010 (Div. A of the Consolidated Appropriations...

  6. High-speed defect detection in rails by non-contact guided ultrasonic testing

    NASA Astrophysics Data System (ADS)

    Rizzo, Piervincenzo; Bartoli, Ivan; Lanza di Scalea, Francesco; Coccia, Stefano; Fateh, Mahmood

    2005-05-01

    Recent train accidents and associated direct and indirect repair costs have reaffirmed the need for developing rail defect detection systems more effective than those used today. The group at the UCSD NDE & Structural Health Monitoring Laboratory, in collaboration with the US Federal Railroad Administration, is conducting a study that aims at developing an inspection strategy for rails based on guided ultrasonic waves. This paper illustrates a guided-wave inspection system that is targeted to the detection of transverse-type cracks in the rail head, that are among the most dangerous flaws in rails. The methodology is based on a hybrid non-contact system that uses a pulsed laser for generating waves and multiple air-coupled sensors for detecting waves. The remote sensors are positioned as far away as 76 mm (3") from the top of rail head. Signal processing based on the Continuous Wavelet Transform is used to characterize the time-frequency content of the propagating waves. Features extracted after Discrete Wavelet processing of the wave signals result in a damage index that is robust with respect to noise and is related to the crack depth; the method allows for fast inspection with the potential for quantifying the extent of the flaw. It is demonstrated that the adopted setup allows for the detection of small cracks, as shallow as 1 mm in depth. It is also shown that the ultrasonic wave features considered in this study are directly related to the reduction of the rail head cross-sectional area caused by a transverse crack.

  7. 75 FR 16562 - High-Speed Intercity Passenger Rail (HSIPR) Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-01

    ... proposals for Federally-led multi- state passenger rail corridor planning demonstration projects. SUMMARY... efforts. The planning project would be identified by the States, but funded and managed by FRA in close... planning project, such as specific institutional barriers or operational complexities. Conditions that...

  8. Local Attitudes Towards AN International Project: a Study of Residents' Attitudes Towards a Future High Speed Rail Line in General and Towards Annoyance in Particular

    NASA Astrophysics Data System (ADS)

    Schaap, D.

    1996-05-01

    Plans for a high speed rail line in Holland generate concerns about the impact on the living environment. Residents living near the planned track have an extremely negative attitude towards the high speed rail line. Most of them do not see the need for the line and they expect a great deal of noise annoyance. There is a disparity between the expectations of the residents and those of the government: the residents expect much more noise that the government does, on the basis of scientific research. The image that residents have of the noise of a high speed train is probably too negative. Therefore the government should supply the residents with better and more detailed information about the noise and the possible annoyance. Furthermore, for a positive attitude, it is important that residents not only recognize the disadvantages of the rail line, but that they recognize some local advantages too. For instances, the government can guarantee compensation for the affected green space, or that other noise sources will be removed. Finally, the residents have the feeling they cannot influence the decision-making process. To reduce this feeling of powerlessness, the government can involve the residents; for example, in the decision-making about the local plans for the high speed rail line.

  9. Cost characteristics of tilt-rotor, conventional air and high speed rail short-haul intercity passenger service

    NASA Technical Reports Server (NTRS)

    Schoendorfer, David L.; Morlok, Edward K.

    1985-01-01

    The cost analysis done to support an assessment of the potential for a small tilt-rotor aircraft to operate in short-haul intercity passenger service is described in detail. Anticipated costs of tilt-rotor air service were compared to the costs of two alternatives: conventional air and high speed rail (HSR). Costs were developed for corridor service, varying key market characteristics including distance, passenger volumes, and minimum frequency standards. The resulting cost vs output information can then be used to compare modal costs for essentially identical service quality and passenger volume or for different service levels and volumes for each mode, as appropriate. Extensive sensitivity analyses are performed. The cost-output features of these technologies are compared. Tilt-rotor is very attractive compared to HSR in terms of costs over the entire range of volume. It also has costs not dramatically different from conventional air, but tilt-rotor costs are generally higher. Thus some of its other advantages, such as the VTOL capability, must offset the cost disadvantage for it to be a preferred or competitive mode in any given market. These issues are addressed in the companion report which considers strategies for tilt-rotor development in commercial air service.

  10. Rail Roughness Study of the Holloman High Speed Rocket Sled Test Track

    DTIC Science & Technology

    1981-09-01

    Test Track My7 6585h Tet Grup (FS .AND t .8A & WORK UHIWT NUMBER II. ~ ~ ~ ~~ 1 CONTROLLINR OFIENM N0DRS C55harTes Group aFS TK 9. DISTRIUTIORNSTATMT...Speed Rocket Sled Test Track. Results of the study will be used to: 1.1.1 Provide forcing functions for Sledyne, a computer simulation program for...one foot intervals along the track. This rationale was justified by the fact that the slope would 3Awkw provide only low frequency forcing functions

  11. 78 FR 22031 - California High-Speed Rail Authority-Construction Exemption-In Merced, Madera and Fresno Counties...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-12

    ... Recommendation and Recirculation of Final Environmental Impact Statement. SUMMARY: In accordance with Surface... the Board adopt a Final Environmental Impact Statement (Final EIS) issued by the Federal Railroad... High-Speed Train: Merced to Fresno Section, Final Project Environmental Impact...

  12. The Effect of Pendolino high-speed rail on the structure of buildings located in the proximity of railway tracks

    NASA Astrophysics Data System (ADS)

    Grębowski, K.; Ulman, Z.

    2016-02-01

    The following research focuses on the dynamic analysis of impact of the high-speed train induced vibrations on the structures located near railway tracks. The office complex chosen as the subject of calculations is located in the northern part of Poland, in Gdańsk, in the proximity of Pendolino, the high speed train route. The high speed trains are the response for the growing needs for a more efficient railway system. However, with a higher speed of the train, the railway induced vibrations might cause more harmful resonance in the structures of the nearby buildings. The damage severity depends on many factors such as the duration of said resonance and the presence of additional loads. The studies and analyses helped to determinate the method of evaluating the impact of railway induced vibrations on any building structure. The dynamic analysis presented in the research is an example of a method which allows an effective calculation of the impact of vibrations via SOFISTIK program.

  13. 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

  14. 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.

  15. High-speed-rail tilt-train technology: A state-of-the-art survey. Final report

    SciTech Connect

    Boon, C.J.; Hayes, W.F.; Kesler, J.K.; Whitten, B.T.

    1992-05-01

    The report presents an assessment of the technical and operational features of existing and proposed tilt-body rail passenger vehicles. Basic concepts of railroad route selection, track geometry, and curve negotiation are reviewed, and the rationale, advantages and disadvantages associated with body tilting and the techniques used to achieve body tilt are discussed. An overview of the development status and selected key characteristics of tilt technologies are presented. Issues associated with deployment and operation of tilt-body technologies in the U..S are identified and analyzed, including a review of U.S. experience to date, areas of incompatibility of foreign tilt technology with existing U.S. equipment and infrastructure, special maintenance procedures and skill requirements, and compliance with FRA and other regulations. Appendices to the report present discussions on the physics of curve negotiation for conventional and tilting vehicles, the principles of tilting and tilt control strategies and mechanisms, and a description and technical characterization of the principal tilt technologies.

  16. A Mathematical Study of Accessibility and Cohesion Degree in a High-Speed Rail Station Connected to an Urban Bus Transport Network

    NASA Astrophysics Data System (ADS)

    Mota, Carmen; López, Miguel A.; Martínez-Rodrigo, Arturo

    2017-04-01

    In the last twenty years, the implementation of High-Speed Rail (HSR) has been one of the major strategies for territorial structuring used by various countries. This model has enhanced the development of countries such as France, Spain, Germany and Japan. At present, the United States and China are also starting to implement this model. Nevertheless, the lack of social and economic profitability of several networks is being increasingly analysed. Many networks located in particular regions serve populations that are not large enough to recover the initial investment. For this reason, it is necessary to evaluate the population served by this transport mode, beyond the number of users. In this sense, it is essential to identify the deficiencies and potentials of implementing a network linked to other secondary networks in a specific territory which can compensate for the so-called tunnel effect. This article proposes to apply a mathematical approach based on graph theory to measure the Degree Accessibility Node (DAN) in a constrained Geographic Information System (GIS) model. Hence, it would be possible to compare regions, especially medium-sized cities, where the implementation of HSR could represent a qualitative leap due to incorporation into large transport networks. The DAN function uses static and dynamic studies to evaluate the level of connection of stations to secondary transport networks—local public transport in this case. Thus, the impact of high-speed trains could be spread to greater territorial and population ranges. Four cases have been studied, two in Germany (one of them, Fulda, is analysed in depth throughout this article) and two in Spain. These two countries were selected since HSR was implemented in the same relative period of time, in comparison with other European countries. Results show relevant differences, suggesting a review of inappropriate policies of transport integration in a city that could weaken the expansion of the positive

  17. Safety of high speed guided ground transportation systems. Magnetic and electric field testing of the French Train a Grande Vitesse (TGV) rail systems. Volume 2. Appendices. Final report, September 1992-March 1993

    SciTech Connect

    Dietrich, F.M.; Jacobs, W.E.

    1993-05-01

    The safety of magnetically levitated (maglev) and high speed rail (HSR) trains proposed for application in the United States is the responsibility of the Federal Railroad Administration (FRA). A franchise has been awarded to the Texas High Speed Rail Corporation to operate a 200 mph French Train a Grande Vitesse (TGV) in the Texas Triangle (Dallas-Fort Worth, Houston, San Antonio), with construction to begin in 1995. The report provides the Analysis (Vol. I) of results, and detailed data and statistical summaries (Vol. II, Appendices) of representative electric and magnetic field (EMF) profiles on TGV-A trains between Paris and Tours for two electro-technologies (1.5 KV DC near Paris, and 2x25 KV at 50 Hz AC).

  18. Safety of high speed guided ground transportation systems. Magnetic and electric field testing of the French Train a Grande Vitesse (TGV) rail systems. Volume 1. Analysis. Final report, September 1992-March 1993

    SciTech Connect

    Dietrich, F.M.; Papas, P.N.; Jacobs, W.L.; Ferro, W.E.

    1993-05-01

    The safety of magnetically levitated (maglev) and high speed rail (HSR) trains proposed for application in the United States is the responsibility of the Federal Railroad Administration (FRA). A franchise has been awarded to the Texas high Speed Rail Corporation to operate a 200 mph French Train a Grande Vitesse (TGV) in the Texas Triangle (Dallas-Fort Worth, Houston, San Antonio), with construction to begin in 1995. The report provides the Analysis (Vol. I) of results, and detailed data and statistical summaries (Vol. II, Appendices) of representative electric and magnetic field (EMF) profiles on TGV-A trains between Paris and Tours for two electro-technologies (1.5 KV DC near Paris, and 2x25 KV at 50 Hz AC).

  19. 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. Final report, October 1991-July 1993

    SciTech Connect

    Goldberg, R.B.; Creasey, W.A.; Foster, K.R.

    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 Low Frequency (3-3,000 Hz) electric and magnetic fields (EMF) produced by these systems. The Environmental Protection Agency's Office of Radiation Programs is assisting the Federal Railroad Administration address these concerns; this comprehensive review is part of that effort. It outlines magnetic field exposure measurements of the TR07 German maglev system compared with other HSR and conventional systems.

  20. Research on determination of the scale of parking space on High Speed Rail Station, using East Ji’nan Station as an example

    NASA Astrophysics Data System (ADS)

    Lv, Jie; Guo, Jianmin; Zhang, Yibin

    2017-08-01

    With the rapid growth of High-Speed Railway network in China, more and more stations has been designed. Based on the work of planning practice, this article has analyzed the influencing factors of proper supplement of parking space in High-Speed Railway Stations with analogy and parking turnover method, and taking East Ji’nan High-Speed Railway Station as an example to give recommended values.

  1. Unsupervised learning algorithm for high-speed defect detection in rails by laser/air-coupled non-contact ultrasonic testing

    NASA Astrophysics Data System (ADS)

    Rizzo, Piervincenzo; Coccia, Stefano; Lanza di Scalea, Francesco; Bartoli, Ivan; Fateh, Mahmood

    2006-03-01

    Recent train accidents and associated direct and indirect costs including cost of repair of equipment and infrastructure as well as delay and death/injury costs, have reaffirmed the need for developing rail defect detection systems more effective than those used today. In fact, rail defect detection has been identified as a priority area in the U.S. Federal Railroad Administration 5-year R&D plan. This paper proposes an unsupervised learning algorithm for defect detection in rails. The algorithm is used in a non-contact inspection system that is targeted to the detection of transverse-type cracks in the rail head (including transverse fissures and detail fractures), notoriously the most dangerous flaws in rails. The system uses ultrasonic guided waves that are generated by a pulsed laser and are detected by air-coupled sensors positioned as far away as 76 mm (3") from the top of rail head. The inspection ranges is at least 500 mm (20") for surface head cracks as shallow as 1 mm. Fast data output is achieved by processing the ultrasonic defect signatures by Wavelet Transform algorithms. The features extracted after wavelet processing are analyzed by a learning algorithm based on novelty detection. This algorithm attempts to detect the presence of damage despite the normal variations in ultrasonic signal features that may be found in a field test.

  2. Numerical investigation on an array of Helmholtz resonators for the reduction of micro-pressure waves in modern and future high-speed rail tunnel systems

    NASA Astrophysics Data System (ADS)

    Tebbutt, J. A.; Vahdati, M.; Carolan, D.; Dear, J. P.

    2017-07-01

    Previous research has proposed that an array of Helmholtz resonators may be an effective method for suppressing the propagation of pressure and sound waves, generated by a high-speed train entering and moving in a tunnel. The array can be used to counteract environmental noise from tunnel portals and also the emergence of a shock wave in the tunnel. The implementation of an array of Helmholtz resonators in current and future high-speed train-tunnel systems is studied. Wave propagation in the tunnel is modelled using a quasi-one-dimensional formulation, accounting for non-linear effects, wall friction and the diffusivity of sound. A multi-objective genetic algorithm is then used to optimise the design of the array, subject to the geometric constraints of a demonstrative tunnel system and the incident wavefront in order to attenuate the propagation of pressure waves. It is shown that an array of Helmholtz resonators can be an effective countermeasure for various tunnel lengths. In addition, the array can be designed to function effectively over a wide operating envelope, ensuring it will still function effectively as train speeds increase into the future.

  3. Electric rail gun projectile acceleration to high velocity

    NASA Technical Reports Server (NTRS)

    Bauer, D. P.; Mccormick, T. J.; Barber, J. P.

    1982-01-01

    Electric rail accelerators are being investigated for application in electric propulsion systems. Several electric propulsion applications require that the rail accelerator be capable of launching projectiles at velocities above 10 km/s. An experimental program was conducted to develop rail accelerator technology for high velocity projectile launch. Several 6 mm bore, 3 m long rail accelerators were fabricated. Projectiles with a mass of 0.2 g were accelerated by plasmas, carrying currents up to 150 kA. Experimental design and results are described. Results indicate that the accelerator performed as predicted for a fraction of the total projectile acceleration. The disparity between predicted and measured results are discussed.

  4. Electric rail gun projectile acceleration to high velocity

    NASA Technical Reports Server (NTRS)

    Bauer, D. P.; Mccormick, T. J.; Barber, J. P.

    1982-01-01

    Electric rail accelerators are being investigated for application in electric propulsion systems. Several electric propulsion applications require that the rail accelerator be capable of launching projectiles at velocities above 10 km/s. An experimental program was conducted to develop rail accelerator technology for high velocity projectile launch. Several 6 mm bore, 3 m long rail accelerators were fabricated. Projectiles with a mass of 0.2 g were accelerated by plasmas, carrying currents up to 150 kA. Experimental design and results are described. Results indicate that the accelerator performed as predicted for a fraction of the total projectile acceleration. The disparity between predicted and measured results are discussed.

  5. The excitation of ground vibration by rail traffic: theory of vehicle track soil interaction and measurements on high-speed lines

    NASA Astrophysics Data System (ADS)

    Auersch, L.

    2005-06-01

    This article presents an integrated model for the computation of vehicle-track interaction and the ground vibrations of passing trains. A combined finite element and boundary element method is used to calculate the dynamic compliance of the track on realistic soil whereas multi-body models are used for the vehicle. The dynamic stiffness of the vehicle and that of the track are combined to calculate the dynamic axle loads due to the irregularities of the vehicle and the track as well as those due to sleeper passing excitation. These loads serve as input for the calculation of ground vibration near railway lines in the time and frequency domains. The theoretical methods and results have been proven by experiments in several respects and at several instances. First, on the occasion of the test and record runs of the Intercity Experimental, there was a very good quality of the vehicle and of the newly built track so that the deterministic parts of the excitation—the static load and the sleeper-passing component—could clearly be identified, the first being of minor importance apart from the track. Second, simultaneous measurements of the vehicle, the track and the soil at three different track situations were performed where we could verify the different parts of the stochastic excitation and their importance for the ground vibrations. The irregularities of the vehicle are dominant at high frequencies whereas the irregularities of the track are more important at lower frequencies. The comparison of the theory and the measurements also points to the phenomena of the vehicle-track resonance and the scattering of the quasi-static axle impulses by randomly varying soil.

  6. Northeast Corridor High-Speed Rail Act

    THOMAS, 111th Congress

    Rep. Castle, Michael N. [R-DE-At Large

    2010-03-12

    House - 03/15/2010 Referred to the Subcommittee on Railroads, Pipelines, and Hazardous Materials. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  7. High pressure common rail injection system modeling and control.

    PubMed

    Wang, H P; Zheng, D; Tian, Y

    2016-07-01

    In this paper modeling and common-rail pressure control of high pressure common rail injection system (HPCRIS) is presented. The proposed mathematical model of high pressure common rail injection system which contains three sub-systems: high pressure pump sub-model, common rail sub-model and injector sub-model is a relative complicated nonlinear system. The mathematical model is validated by the software Matlab and a virtual detailed simulation environment. For the considered HPCRIS, an effective model free controller which is called Extended State Observer - based intelligent Proportional Integral (ESO-based iPI) controller is designed. And this proposed method is composed mainly of the referred ESO observer, and a time delay estimation based iPI controller. Finally, to demonstrate the performances of the proposed controller, the proposed ESO-based iPI controller is compared with a conventional PID controller and ADRC.

  8. Multi-point contact of the high-speed vehicle-turnout system dynamics

    NASA Astrophysics Data System (ADS)

    Ren, Zunsong

    2013-05-01

    The wheel-rail contact problems, such as the number, location and the track of contact patches, are very important for optimizing the spatial structure of the rails and lowering the vehicle-turnout system dynamics. However, the above problems are not well solved currently because of having the difficulties in how to determine the multi-contact, to preciously present the changeable profiles of the rails and to establish an accurate spatial turnout system dynamics model. Based on a high-speed vehicle-turnout coupled model in which the track is modeled as flexible with rails and sleepers represented by beams, the line tracing extreme point method is introduced to investigate the wheel-rail multiple contact conditions and the key sections of the blade rail, longer nose rail, shorter rail in the switch and nose rail area are discretized to represent the varying profiles of rails in the turnout. The dynamic interaction between the vehicle and turnout is simulated for cases of the vehicle divergently passing the turnout and the multi-point contact is obtained. The tracks of the contact patches on the top of the rails are presented and the wheel-rail impact forces are offered in comparison with the contact patches transference on the rails. The numerical simulation results indicate that the length of two-point contact occurrence of a worn wheel profile and rails is longer than that of the new wheel profile and rails; The two-point contact definitely occurs in the switch and crossing area. Generally, three-point contact doesn't occur for the new rail profile, which is testified by the wheel-rails interpolation distance and the first order derivative function of the tracing line extreme points. The presented research is not only helpful to optimize the structure of the turnout, but also useful to lower the dynamics of the high speed vehicle-turnout system.

  9. High-gain, high-bandwidth, rail-to-rail, constant-gm CMOS operational amplifier

    NASA Astrophysics Data System (ADS)

    Huang, Hong-Yi; Wang, Bo-Ruei

    2013-01-01

    This study presents a high-gain, high-bandwidth, constant-gm , rail-to-rail operational amplifier (op-amp). The constant transconductance is improved with a source-to-bulk bias control of an input pair. A source degeneration scheme is also adapted to the output stage for receiving wide input range without degradation of the gain. Additionally, several compensation schemes are employed to enhance the stability. A test chip is fabricated in a 0.18 µm complementary metal-oxide semiconductor process. The active area of the op-amp is 181 × 173 µm2 and it consumes a power of 2.41 mW at a supply voltage of 1.8 V. The op-amp achieves a dc gain of 94.3 dB and a bandwidth of 45 MHz when the output capacitive load is connected to an effective load of 42.5 pF. A class-AB output stage combining a slew rate (SR) boost circuit provides a sinking current of 6 mA and an SR of 17 V/µs.

  10. High speed handpieces

    PubMed Central

    Bhandary, Nayan; Desai, Asavari; Shetty, Y Bharath

    2014-01-01

    High speed instruments are versatile instruments used by clinicians of all specialties of dentistry. It is important for clinicians to understand the types of high speed handpieces available and the mechanism of working. The centers for disease control and prevention have issued guidelines time and again for disinfection and sterilization of high speed handpieces. This article presents the recent developments in the design of the high speed handpieces. With a view to prevent hospital associated infections significant importance has been given to disinfection, sterilization & maintenance of high speed handpieces. How to cite the article: Bhandary N, Desai A, Shetty YB. High speed handpieces. J Int Oral Health 2014;6(1):130-2. PMID:24653618

  11. High Speed Research Program

    NASA Technical Reports Server (NTRS)

    Anderson, Robert E.; Corsiglia, Victor R.; Schmitz, Frederic H. (Technical Monitor)

    1994-01-01

    An overview of the NASA High Speed Research Program will be presented from a NASA Headquarters perspective. The presentation will include the objectives of the program and an outline of major programmatic issues.

  12. High-Speed Photography

    SciTech Connect

    Paisley, D.L.; Schelev, M.Y.

    1998-08-01

    The applications of high-speed photography to a diverse set of subjects including inertial confinement fusion, laser surgical procedures, communications, automotive airbags, lightning etc. are briefly discussed. (AIP) {copyright} {ital 1998 Society of Photo-Optical Instrumentation Engineers.}

  13. High speed flywheel

    SciTech Connect

    McGrath, S.V.

    1990-01-01

    This invention relates generally to flywheels and relates more particularly to the construction of a high speed, low-mass flywheel. Flywheels with which this invention is to be compared include those constructed of circumferentially wound filaments or fibers held together by a matrix or bonding material. Flywheels of such construction are known to possess a relatively high hoop strength but a relatively low radial strength. Hoop-wound flywheels are, therefore, particularly susceptible to circumferential cracks, and the radial stress limitations of such a flywheel substantially limit its speed capabilities. It is an object of the present invention to provide a new and improved flywheel which experiences reduced radial stress at high operating speeds. Another object of the present invention is to provide flywheel whose construction allows for radial growth as flywheel speed increases while providing the necessary stiffness for transferring and maintaining kinetic energy within the flywheel. Still another object of the present invention is to provide a flywheel having concentrically-disposed component parts wherein rotation induced radial stresses at the interfaces of such component parts approach zero. Yet another object of the present invention is to provide a flywheel which is particularly well-suited for high speed applications. 5 figs.

  14. High Speed Ice Friction

    NASA Astrophysics Data System (ADS)

    Seymour-Pierce, Alexandra; Sammonds, Peter; Lishman, Ben

    2014-05-01

    Many different tribological experiments have been run to determine the frictional behaviour of ice at high speeds, ostensibly with the intention of applying results to everyday fields such as winter tyres and sports. However, experiments have only been conducted up to linear speeds of several metres a second, with few additional subject specific studies reaching speeds comparable to these applications. Experiments were conducted in the cold rooms of the Rock and Ice Physics Laboratory, UCL, on a custom built rotational tribometer based on previous literature designs. Preliminary results from experiments run at 2m/s for ice temperatures of 271 and 263K indicate that colder ice has a higher coefficient of friction, in accordance with the literature. These results will be presented, along with data from further experiments conducted at temperatures between 259-273K (in order to cover a wide range of the temperature dependent behaviour of ice) and speeds of 2-15m/s to produce a temperature-velocity-friction map for ice. The effect of temperature, speed and slider geometry on the deformation of ice will also be investigated. These speeds are approaching those exhibited by sports such as the luge (where athletes slide downhill on an icy track), placing the tribological work in context.

  15. Safety assessment of underground vehicles passing over highly resilient curved tracks in the presence of a broken rail

    NASA Astrophysics Data System (ADS)

    Suárez, B.; Rodriguez, P.; Vázquez, M.; Fernández, I.

    2012-01-01

    Vehicle-track interaction for a new resilient slab track designed to reduce noise and vibration levels was analysed, in order to assess the derailment risk on a curved track when encountering a broken rail. Sensitivity of the rail support spacing of the relative position of the rail breakage between two adjacent rail supports and of running speed were analysed for two different elasticities of the rail fastening system. In none of the cases analysed was observed an appreciable difference between either of the elastic systems. As was expected, the most unfavourable situations were those with greater rail support spacing and those with greater distance from the breakage to the nearest rail support, although in none of the simulations performed did a derailment occur when running over the broken rail. When varying the running speed, the most favourable condition was obtained for an intermediate speed, due to the superposition of two antagonistic effects.

  16. 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.

  17. 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.

  18. High Speed Vortex Flows

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Wilcox, Floyd J., Jr.; Bauer, Steven X. S.; Allen, Jerry M.

    2000-01-01

    A review of the research conducted at the National Aeronautics and Space Administration (NASA), Langley Research Center (LaRC) into high-speed vortex flows during the 1970s, 1980s, and 1990s is presented. The data reviewed is for flat plates, cavities, bodies, missiles, wings, and aircraft. These data are presented and discussed relative to the design of future vehicles. Also presented is a brief historical review of the extensive body of high-speed vortex flow research from the 1940s to the present in order to provide perspective of the NASA LaRC's high-speed research results. Data are presented which show the types of vortex structures which occur at supersonic speeds and the impact of these flow structures to vehicle performance and control is discussed. The data presented shows the presence of both small- and large scale vortex structures for a variety of vehicles, from missiles to transports. For cavities, the data show very complex multiple vortex structures exist at all combinations of cavity depth to length ratios and Mach number. The data for missiles show the existence of very strong interference effects between body and/or fin vortices and the downstream fins. It was shown that these vortex flow interference effects could be both positive and negative. Data are shown which highlights the effect that leading-edge sweep, leading-edge bluntness, wing thickness, location of maximum thickness, and camber has on the aerodynamics of and flow over delta wings. The observed flow fields for delta wings (i.e. separation bubble, classical vortex, vortex with shock, etc.) are discussed in the context of' aircraft design. And data have been shown that indicate that aerodynamic performance improvements are available by considering vortex flows as a primary design feature. Finally a discussing of a design approach for wings which utilize vortex flows for improved aerodynamic performance at supersonic speed is presented.

  19. High Speed Video Insertion

    NASA Astrophysics Data System (ADS)

    Janess, Don C.

    1984-11-01

    This paper describes a means of inserting alphanumeric characters and graphics into a high speed video signal and locking that signal to an IRIG B time code. A model V-91 IRIG processor, developed by Instrumentation Technology Systems under contract to Instrumentation Marketing Corporation has been designed to operate in conjunction with the NAC model FHS-200 High Speed Video Camera which operates at 200 fields per second. The system provides for synchronizing the vertical and horizontal drive signals such that the vertical sync precisely coincides with five millisecond transitions in the IRIG time code. Additionally, the unit allows for the insertion of an IRIG time message as well as other data and symbols.

  20. Safety of high speed ground transportation systems: Safety of advanced braking concepts for high speed ground transportation systems. Final report

    SciTech Connect

    Wagner, D.P.; Ahlbeck, D.R.; Luedeke, J.F.; Cook, S.D.; Dielman, M.A.

    1995-09-01

    The objective of this study is to develop qualitative and quantitative information on the various braking strategies used in high-speed ground transportation systems in support of the Federal Railroad Administration (FRA). The approach employed in this study is composed of two steps: first, build a technical understanding of the various braking strategies, and second, perform a safety analysis for each system. The systems considered in this study include seven operating high-speed rail transportation systems and three existing magnetic levitation systems. The principal technique used in the system safety analysis is Failure Modes and Effects Analysis (FMEA), an inductive approach to identifying system failure modes that depends on a thorough understanding of the system design and operation. Key elements derived from the system safety analysis are the fault-tolerant and fail-safe characteristics of the braking systems. The report concludes with recommended guidance on the structure of potential future regulations governing high-speed rail braking systems.

  1. High speed multiphoton imaging

    NASA Astrophysics Data System (ADS)

    Li, Yongxiao; Brustle, Anne; Gautam, Vini; Cockburn, Ian; Gillespie, Cathy; Gaus, Katharina; Lee, Woei Ming

    2016-12-01

    Intravital multiphoton microscopy has emerged as a powerful technique to visualize cellular processes in-vivo. Real time processes revealed through live imaging provided many opportunities to capture cellular activities in living animals. The typical parameters that determine the performance of multiphoton microscopy are speed, field of view, 3D imaging and imaging depth; many of these are important to achieving data from in-vivo. Here, we provide a full exposition of the flexible polygon mirror based high speed laser scanning multiphoton imaging system, PCI-6110 card (National Instruments) and high speed analog frame grabber card (Matrox Solios eA/XA), which allows for rapid adjustments between frame rates i.e. 5 Hz to 50 Hz with 512 × 512 pixels. Furthermore, a motion correction algorithm is also used to mitigate motion artifacts. A customized control software called Pscan 1.0 is developed for the system. This is then followed by calibration of the imaging performance of the system and a series of quantitative in-vitro and in-vivo imaging in neuronal tissues and mice.

  2. High speed civil transport

    NASA Technical Reports Server (NTRS)

    Bogardus, Scott; Loper, Brent; Nauman, Chris; Page, Jeff; Parris, Rusty; Steinbach, Greg

    1990-01-01

    The design process of the High Speed Civil Transport (HSCT) combines existing technology with the expectation of future technology to create a Mach 3.0 transport. The HSCT was designed to have a range in excess of 6000 nautical miles and carry up to 300 passengers. This range will allow the HSCT to service the economically expanding Pacific Basin region. Effort was made in the design to enable the aircraft to use conventional airports with standard 12,000 foot runways. With a takeoff thrust of 250,000 pounds, the four supersonic through-flow engines will accelerate the HSCT to a cruise speed of Mach 3.0. The 679,000 pound (at takeoff) HSCT is designed to cruise at an altitude of 70,000 feet, flying above most atmospheric disturbances.

  3. High speed flywheel

    DOEpatents

    McGrath, Stephen V.

    1991-01-01

    A flywheel for operation at high speeds utilizes two or more ringlike coments arranged in a spaced concentric relationship for rotation about an axis and an expansion device interposed between the components for accommodating radial growth of the components resulting from flywheel operation. The expansion device engages both of the ringlike components, and the structure of the expansion device ensures that it maintains its engagement with the components. In addition to its expansion-accommodating capacity, the expansion device also maintains flywheel stiffness during flywheel operation.

  4. High speed flywheel

    SciTech Connect

    McGrath, S.V.

    1991-05-07

    This patent describes a flywheel for operation at high speed which utilizes two or more ringlike components arranged in a spaced concentric relationship for rotation about an axis and an expansion device interposed between the components for accommodating radial growth of the components resulting from flywheel operation. The expansion device engages both of the ringlike components, and the structure of the expansion device ensures that it maintains its engagement with the components. In addition to its expansion-accommodating capacity, the expansion device also maintains flywheel stiffness during flywheel operation.

  5. High speed transient sampler

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    A high speed sampler comprises a meandered sample transmission line for transmitting an input signal, a straight strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates along the transmission lines. The sampling gates comprise a four terminal diode bridge having a first strobe resistor connected from a first terminal of the bridge to the positive strobe line, a second strobe resistor coupled from the third terminal of the bridge to the negative strobe line, a tap connected to the second terminal of the bridge and to the sample transmission line, and a sample holding capacitor connected to the fourth terminal of the bridge. The resistance of the first and second strobe resistors is much higher than the signal transmission line impedance in the preferred system. This results in a sampling gate which applies a very small load on the sample transmission line and on the strobe generator. The sample holding capacitor is implemented using a smaller capacitor and a larger capacitor isolated from the smaller capacitor by resistance. The high speed sampler of the present invention is also characterized by other optimizations, including transmission line tap compensation, stepped impedance strobe line, a multi-layer physical layout, and unique strobe generator design. A plurality of banks of such samplers are controlled for concatenated or interleaved sample intervals to achieve long sample lengths or short sample spacing.

  6. High speed transient sampler

    DOEpatents

    McEwan, T.E.

    1995-11-28

    A high speed sampler comprises a meandered sample transmission line for transmitting an input signal, a straight strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates along the transmission lines. The sampling gates comprise a four terminal diode bridge having a first strobe resistor connected from a first terminal of the bridge to the positive strobe line, a second strobe resistor coupled from the third terminal of the bridge to the negative strobe line, a tap connected to the second terminal of the bridge and to the sample transmission line, and a sample holding capacitor connected to the fourth terminal of the bridge. The resistance of the first and second strobe resistors is much higher than the signal transmission line impedance in the preferred system. This results in a sampling gate which applies a very small load on the sample transmission line and on the strobe generator. The sample holding capacitor is implemented using a smaller capacitor and a larger capacitor isolated from the smaller capacitor by resistance. The high speed sampler of the present invention is also characterized by other optimizations, including transmission line tap compensation, stepped impedance strobe line, a multi-layer physical layout, and unique strobe generator design. A plurality of banks of such samplers are controlled for concatenated or interleaved sample intervals to achieve long sample lengths or short sample spacing. 17 figs.

  7. HIGH SPEED CAMERA

    DOEpatents

    Rogers, B.T. Jr.; Davis, W.C.

    1957-12-17

    This patent relates to high speed cameras having resolution times of less than one-tenth microseconds suitable for filming distinct sequences of a very fast event such as an explosion. This camera consists of a rotating mirror with reflecting surfaces on both sides, a narrow mirror acting as a slit in a focal plane shutter, various other mirror and lens systems as well as an innage recording surface. The combination of the rotating mirrors and the slit mirror causes discrete, narrow, separate pictures to fall upon the film plane, thereby forming a moving image increment of the photographed event. Placing a reflecting surface on each side of the rotating mirror cancels the image velocity that one side of the rotating mirror would impart, so as a camera having this short a resolution time is thereby possible.

  8. High speed nozzles task

    NASA Technical Reports Server (NTRS)

    Hamed, Awatef

    1995-01-01

    Supersonic cruise exhaust nozzles for advanced applications are optimized for a high nozzle pressure ratio (NPR) at design supersonic cruise Mach number and altitude. The performance of these nozzles with large expansion ratios are severely degraded for operations at subsonic speeds near sea level for NPR significantly less than the design values. The prediction of over-expanded 2DCD nozzles performance is critical to evaluating the internal losses and to the optimization of the integrated vehicle and propulsion system performance. The reported research work was aimed at validating and assessing existing computational methods and turbulence models for predicting the flow characteristics and nozzle performance at over-expanded conditions. Flow simulations in 2DCD nozzles were performed using five different turbulence models. The results are compared with the experimental data for the wall pressure distribution and thrust and flow coefficients at over-expanded static conditions.

  9. High speed packet switching

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This document constitutes the final report prepared by Proteon, Inc. of Westborough, Massachusetts under contract NAS 5-30629 entitled High-Speed Packet Switching (SBIR 87-1, Phase 2) prepared for NASA-Greenbelt, Maryland. The primary goal of this research project is to use the results of the SBIR Phase 1 effort to develop a sound, expandable hardware and software router architecture capable of forwarding 25,000 packets per second through the router and passing 300 megabits per second on the router's internal busses. The work being delivered under this contract received its funding from three different sources: the SNIPE/RIG contract (Contract Number F30602-89-C-0014, CDRL Sequence Number A002), the SBIR contract, and Proteon. The SNIPE/RIG and SBIR contracts had many overlapping requirements, which allowed the research done under SNIPE/RIG to be applied to SBIR. Proteon funded all of the work to develop new router interfaces other than FDDI, in addition to funding the productization of the router itself. The router being delivered under SBIR will be a fully product-quality machine. The work done during this contract produced many significant findings and results, summarized here and explained in detail in later sections of this report. The SNIPE/RIG contract was completed. That contract had many overlapping requirements with the SBIR contract, and resulted in the successful demonstration and delivery of a high speed router. The development that took place during the SNIPE/RIG contract produced findings that included the choice of processor and an understanding of the issues surrounding inter processor communications in a multiprocessor environment. Many significant speed enhancements to the router software were made during that time. Under the SBIR contract (and with help from Proteon-funded work), it was found that a single processor router achieved a throughput significantly higher than originally anticipated. For this reason, a single processor router was

  10. High speed civil transport

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This report discusses the design and marketability of a next generation supersonic transport. Apogee Aeronautics Corporation has designated its High Speed Civil Transport (HSCT): Supercruiser HS-8. Since the beginning of the Concorde era, the general consensus has been that the proper time for the introduction of a next generation Supersonic Transport (SST) would depend upon the technical advances made in the areas of propulsion (reduction in emissions) and material composites (stronger, lighter materials). It is believed by many in the aerospace industry that these beforementioned technical advances lie on the horizon. With this being the case, this is the proper time to begin the design phase for the next generation HSCT. The design objective for a HSCT was to develop an aircraft that would be capable of transporting at least 250 passengers with baggage at a distance of 5500 nmi. The supersonic Mach number is currently unspecified. In addition, the design had to be marketable, cost effective, and certifiable. To achieve this goal, technical advances in the current SST's must be made, especially in the areas of aerodynamics and propulsion. As a result of these required aerodynamic advances, several different supersonic design concepts were reviewed.

  11. Non-contact ultrasonic guided wave inspections of rails

    NASA Astrophysics Data System (ADS)

    Nguyen, Thompson V.; Mariani, Stefano; Lanza di Scalea, Francesco

    2014-03-01

    The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail integrity evaluation. A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection, in pair with a real-time statistical analysis algorithm, is under development. Experimental tests results, carried out at the UCSD Rail Defect Farm, indicate that the prototype is able to detect internal rail defects with high reliability. Extensions of the system are planned to add rail surface characterization to the internal rail defect detection.

  12. Development of magnetically levitated high speed transport system in Japan

    SciTech Connect

    Sawada, Kazuo

    1996-07-01

    In Japan, huge passenger traffic moves through the Tokyo-Osaka corridor and the demand is mounting on one more high speed line besides the Tokaido Shinkansen. A magnetically levitated vehicle (JR Maglev) using superconducting magnets has been developed for the Tokyo-Osaka superspeed express. JR Maglev has many advantages over conventional rail systems. This paper describes the necessity of one more high speed line in this corridor, the reason the author chose Maglev, the scheme of this system, history of the development and outline of the new Yamanashi test line project.

  13. Safety of high speed ground transportation systems. High speed passenger trains in freight railroad corridors: Operations and safety considerations. Final report, September 1993-April 1994

    SciTech Connect

    Ullman, K.B.; Bing, A.J.

    1994-12-01

    This report presents the results of a study into some operations and technical issues likely to be encountered when planning for high-speed rail passenger service on corridors that presently carry freight or commuter traffic. The study starts with a review of corridors designated under Section 1010 of the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991, a potential future high-speed corridors. After a review of signal, train control and braking systems presently used in the United States and elsewhere, the study provides analyses of the safety and operations impacts of introducing high-speed rail service on the hypothetical corridor. The safety analysis established a safety performance target based on present intercity rail safety performance, and reviewed the need for and benefits from safety improvements for high speed operation. The operations analysis concentrated on the impacts on track capacity and train delays of introducing a high-speed rail service on three hypothetical existing corridors with different track layouts and signal systems.

  14. High speed transition prediction

    NASA Technical Reports Server (NTRS)

    Gasperas, Gediminis

    1992-01-01

    The main objective of this work period was to develop, acquire and apply state-of-the-art tools for the prediction of transition at high speeds at NASA Ames. Although various stability codes as well as basic state codes were acquired, the development of a new Parabolized Stability Equation (PSE) code was minimal. The time that was initially allocated for development was used on other tasks, in particular for the Leading Edge Suction problem, in acquiring proficiency in various graphics tools, and in applying these tools to evaluate various Navier-Stokes and Euler solutions. The second objective of this work period was to attend the Transition and Turbulence Workshop at NASA Langley in July and August, 1991. A report on the Workshop follows. From July 8, 1991 to August 2, 1991, the author participated in the Transition and Turbulence Workshop at NASA Langley. For purposes of interest here, analysis can be said to consist of solving simplified governing equations by various analytical methods, such as asymptotic methods, or by use of very meager computer resources. From the composition of the various groups at the Workshop, it can be seen that analytical methods are generally more popular in Great Britain than they are in the U.S., possibly due to historical factors and the lack of computer resources. Experimenters at the Workshop were mostly concerned with subsonic flows, and a number of demonstrations were provided, among which were a hot-wire experiment to probe the boundary layer on a rotating disc, a hot-wire rake to map a free shear layer behind a cylinder, and the use of heating strips on a flat plate to control instability waves and consequent transition. A highpoint of the demonstrations was the opportunity to observe the rather noisy 'quiet' supersonic pilot tunnel in operation.

  15. High Speed Metal Removal

    DTIC Science & Technology

    1982-10-01

    values showed an unusual wear pattern, so the cutting speed was lowered to 440 feet per minute. When the results of these tests were plotted, this curve...again showed unusual wear. From this chart. Figure 6, Page 16, values of 3100 square inches of machined area, at a surface speed of 440 feet per...G RA DE _ 5P0 / f— r- s FM _ 4 00 F r. /M IN / O F RF D _ ,0 22 i N. / RPV / UJ 3 0 0 0- t // / Q. / / — LU O < t / / LL / / W 2 0 0

  16. High speed metal removal

    NASA Astrophysics Data System (ADS)

    Pugh, R. F.; Pohl, R. F.

    1982-10-01

    Four types of steel (AISI 1340, 4140, 4340, and HF-1) which are commonly used in large caliber projectile manufacture were machined at different hardness ranges representing the as-forged and the heat treated condition with various ceramic tools using ceramic coated tungsten carbide as a reference. Results show that machining speeds can be increased significantly using present available tooling.

  17. Focused Mission High Speed Combatant

    DTIC Science & Technology

    2003-05-09

    hull types to determine which hull type best meets the requirements for the Focused Mission High Speed Combatant. The first step in the analysis...MAPC, uses parametric models and scaling to create high level designs of various hull types. The inputs are desired speed , range, payload, sea state...reached 10 SWATH vessels exhibit superior seakeeping at near zero speed compared to other hull forms 5 Assumes 2 equal-sized GE Gas Turbines 11

  18. Effect of chemical composition on the hardenability of high-strength rail steel

    NASA Astrophysics Data System (ADS)

    Safonova, K. É.; Velikanov, A. V.

    1981-05-01

    The hardenability nomograms developed for high-strength rail steels make it possible to select the composition of steel with a given hardenability, the minimal permissible value of which depends on the operating conditions.

  19. Mass splitting of train wheels in the numerical analysis of high speed train-track interactions

    NASA Astrophysics Data System (ADS)

    Dyniewicz, Bartłomiej; Bajer, Czesław I.; Matej, Jan

    2015-01-01

    We demonstrate that the dynamic simulation of a vehicle moving on a track requires the correct mass distribution in the wheel-rail system. A wheel travelling on a rail should be modelled as a pair of masses coupled as a double mass oscillator. One of the masses is attached to the rail and carries the moving inertial load, while the second one is treated classically, being connected to the rail only through an elastic spring. This model is called the 'mass splitting model'. The classical approach overestimates the accelerations by a factor of 10. The presented method produces displacements and velocities which agree well with the results of a precise finite element method and with measurements. Some real-life problems of a vehicle moving on a track at high speed are solved numerically by own computer program and the results are compared with measurements and with the solutions obtained using other codes.

  20. Lubricity Doser Evaluation Studies on High Pressure Common Rail Fuel Systems

    DTIC Science & Technology

    2014-05-01

    high-pressure common rail system found on John Deere 4.5L Powertech Engines. The completion of a modified test protocol based on the NATO test cycle...Pressure Common Rail (HPCR) fuel system found on a John Deere 4.5L PowetechPlus engine. The three fuels that were tested on the HPCR test rig with...for John Deere HPCR Pump Stand ............................................................................. 10 Table 3. Test Fuels and Summary of

  1. A Study of Slipper and Rail Wear Interaction at Low Speed

    DTIC Science & Technology

    2014-06-19

    and Radiation Transport Diffusion DADS Dynamic Analysis of Dynamic Systems EOS Equation of State FEM finite element model HHSTT Holloman High Speed Test...Ancient drills fashioned with antler or bone bearings were used with bows to drill holes or to create fire with tinder[6]. In a fresco from 1880 BC...Abaqus[1] finite element model ( FEM ) is used to simulate the collision of aVascoMax 300 slipper with a leading edge of radius 6 µm with a AISI-1080 steel

  2. High-Speed Electrochemical Imaging.

    PubMed

    Momotenko, Dmitry; Byers, Joshua C; McKelvey, Kim; Kang, Minkyung; Unwin, Patrick R

    2015-09-22

    The design, development, and application of high-speed scanning electrochemical probe microscopy is reported. The approach allows the acquisition of a series of high-resolution images (typically 1000 pixels μm(-2)) at rates approaching 4 seconds per frame, while collecting up to 8000 image pixels per second, about 1000 times faster than typical imaging speeds used up to now. The focus is on scanning electrochemical cell microscopy (SECCM), but the principles and practicalities are applicable to many electrochemical imaging methods. The versatility of the high-speed scan concept is demonstrated at a variety of substrates, including imaging the electroactivity of a patterned self-assembled monolayer on gold, visualization of chemical reactions occurring at single wall carbon nanotubes, and probing nanoscale electrocatalysts for water splitting. These studies provide movies of spatial variations of electrochemical fluxes as a function of potential and a platform for the further development of high speed scanning with other electrochemical imaging techniques.

  3. SEAL FOR HIGH SPEED CENTRIFUGE

    DOEpatents

    Skarstrom, C.W.

    1957-12-17

    A seal is described for a high speed centrifuge wherein the centrifugal force of rotation acts on the gasket to form a tight seal. The cylindrical rotating bowl of the centrifuge contains a closure member resting on a shoulder in the bowl wall having a lower surface containing bands of gasket material, parallel and adjacent to the cylinder wall. As the centrifuge speed increases, centrifugal force acts on the bands of gasket material forcing them in to a sealing contact against the cylinder wall. This arrangememt forms a simple and effective seal for high speed centrifuges, replacing more costly methods such as welding a closure in place.

  4. Gated high speed optical detector

    NASA Technical Reports Server (NTRS)

    Green, S. I.; Carson, L. M.; Neal, G. W.

    1973-01-01

    The design, fabrication, and test of two gated, high speed optical detectors for use in high speed digital laser communication links are discussed. The optical detectors used a dynamic crossed field photomultiplier and electronics including dc bias and RF drive circuits, automatic remote synchronization circuits, automatic gain control circuits, and threshold detection circuits. The equipment is used to detect binary encoded signals from a mode locked neodynium laser.

  5. Wheel/rail contact geometry assessment to limit rolling contact fatigue initiation at high axle loads

    NASA Astrophysics Data System (ADS)

    Fröhling, Robert; Spangenberg, Ulrich; Hettasch, Georg

    2012-01-01

    Rolling contact fatigue on any railway system has a significant impact on the safety and efficiency of the operation. This is especially true for heavy haul railways where higher axle loads and demands for higher throughput have, over the years, challenged the limits within the wheel/rail interface. The objective of this paper is to present a methodology to manage this stress state using a detailed wheel/rail contact stress analysis. Based on the results of recent wheel profile and rail profile surveys, a kinematic wheel/rail contact analysis is performed to identify and eliminate profiles that cause high stresses. The results show that the current hollow wear criterion is effective, but that an alternative or additional criterion based on the gauge side false flange gradient or the calculated peak contact stress values can further reduce the stress state. Within the wheel and rail profile combinations investigated, the contact stresses were largely independent of the transverse profile of the high rail.

  6. Comparison of high-speed rail and maglev system costs

    SciTech Connect

    Rote, D.M.

    1998-07-01

    This paper compares the two modes of transportation, and notes important similarities and differences in the technologies and in how they can be implemented to their best advantage. Problems with making fair comparisons of the costs and benefits are discussed and cost breakdowns based on data reported in the literature are presented and discussed in detail. Cost data from proposed and actual construction projects around the world are summarized and discussed. Results from the National Maglev Initiative and the recently-published Commercial Feasibility Study are included in the discussion. Finally, estimates will be given of the expected cost differences between HSR and maglev systems implemented under simple and complex terrain conditions. The extent to which the added benefits of maglev technology offset the added costs is examined.

  7. High speed optical networks

    NASA Astrophysics Data System (ADS)

    Frankel, Michael Y.; Livas, Jeff

    2005-02-01

    This overview will discuss core network technology and cost trade-offs inherent in choosing between "analog" architectures with high optical transparency, and ones heavily dependent on frequent "digital" signal regeneration. The exact balance will be related to the specific technology choices in each area outlined above, as well as the network needs such as node geographic spread, physical connectivity patterns, and demand loading. Over the course of a decade, optical networks have evolved from simple single-channel SONET regenerator-based links to multi-span multi-channel optically amplified ultra-long haul systems, fueled by high demand for bandwidth at reduced cost. In general, the cost of a well-designed high capacity system is dominated by the number of optical to electrical (OE) and electrical to optical (EO) conversions required. As the reach and channel capacity of the transport systems continued to increase, it became necessary to improve the granularity of the demand connections by introducing (optical add/drop multiplexers) OADMs. Thus, if a node requires only small demand connectivity, most of the optical channels are expressed through without regeneration (OEO). The network costs are correspondingly reduced, partially balanced by the increased cost of the OADM nodes. Lately, the industry has been aggressively pursuing a natural extension of this philosophy towards all-optical "analog" core networks, with each demand touching electrical digital circuitry only at the in/egress nodes. This is expected to produce a substantial elimination of OEO costs, increase in network capacity, and a notionally simpler operation and service turn-up. At the same time, such optical "analog" network requires a large amount of complicated hardware and software for monitoring and manipulating high bit rate optical signals. New and more complex modulation formats that provide resiliency to both optical noise and nonlinear propagation effects are important for extended

  8. Flexible high speed CODEC

    NASA Technical Reports Server (NTRS)

    Wernlund, James V.

    1993-01-01

    HARRIS, under contract with NASA Lewis, has developed a hard decision BCH (Bose-Chaudhuri-Hocquenghem) triple error correcting block CODEC ASIC, that can be used in either a bursted or continuous mode. the ASIC contains both encoder and decoder functions, programmable lock thresholds, and PSK related functions. The CODEC provides up to 4 dB of coding gain for data rates up to 300 Mbps. The overhead is selectable from 7/8 to 15/16 resulting in minimal band spreading, for a given BER. Many of the internal calculations are brought out enabling the CODEC to be incorporated in more complex designs. The ASIC has been tested in BPSK, QPSK and 16-ary PSK link simulators and found to perform to within 0.1 dB of theory for BER's of 10(exp -2) to 10(exp -9). The ASIC itself, being a hard decision CODEC, is not limited to PSK modulation formats. Unlike most hard decision CODEC's, the HARRIS CODEC doesn't upgrade BER performance significantly at high BER's but rather becomes transparent.

  9. Analysis of torque transmitting behavior and wheel slip prevention control during regenerative braking for high speed EMU trains

    NASA Astrophysics Data System (ADS)

    Xu, Kun; Xu, Guo-Qing; Zheng, Chun-Hua

    2016-04-01

    The wheel-rail adhesion control for regenerative braking systems of high speed electric multiple unit trains is crucial to maintaining the stability, improving the adhesion utilization, and achieving deep energy recovery. There remain technical challenges mainly because of the nonlinear, uncertain, and varying features of wheel-rail contact conditions. This research analyzes the torque transmitting behavior during regenerative braking, and proposes a novel methodology to detect the wheel-rail adhesion stability. Then, applications to the wheel slip prevention during braking are investigated, and the optimal slip ratio control scheme is proposed, which is based on a novel optimal reference generation of the slip ratio and a robust sliding mode control. The proposed methodology achieves the optimal braking performance without the wheel-rail contact information. Numerical simulation results for uncertain slippery rails verify the effectiveness of the proposed methodology.

  10. High speed trains. (Latest citations from the EI Compendex*plus database). Published Search

    SciTech Connect

    Not Available

    1994-06-01

    The bibliography contains citations concerning high speed, or bullet trains. References cover systems developed in the U.S., France, Germany, Italy, Japan, and Sweden. Topics include brake systems, telecommunications, electric drive systems, pressure tight connections and doors requirements, and wheel/rail noise suppression. (Contains a minimum of 107 citations and includes a subject term index and title list.)

  11. 08FFL-0020Influence of High Fuel Rail Pressure and Urea Selective Catalytic Reduction on PM Formation in an Off-Highway Heavy-Duty Diesel Engine

    SciTech Connect

    Kass, Michael D; Domingo, Norberto; Storey, John Morse; Lewis Sr, Samuel Arthur

    2008-01-01

    The influence of fuel rail pressure (FRP) and urea-selective catalytic reduction (SCR) on particulate matter (PM) formation is investigated in this paper along with notes regarding the NOx and other emissions. Increasing FRP was shown to reduce the overall soot and total PM mass for four operating conditions. These conditions included two high speed conditions (2400 rpm at 540 and 270 Nm of torque) and two moderated speed conditions (1400 rpm at 488 and 325 Nm). The concentrations of CO2 and NOx increased with fuel rail pressure and this is attributed to improved fuel-air mixing. Interestingly, the level of unburned hydrocarbons remained constant (or increased slightly) with increased FRP. PM concentration was measured using an AVL smoke meter and scanning mobility particle sizer (SMPS); and total PM was collected using standard gravimetric techniques. These results showed that the smoke number and particulate concentrations decrease with increasing FRP. However the decrease becomes more gradual as very high rail pressures. Additionally, the total PM decreased with increasing FRP; however, the soluble organic fraction (SOF) reaches a maximum after which it declines with higher rail pressure. The total PM was collected for the two 1400 rpm conditions downstream of the engine, diesel oxidation catalyst, and a urea-SCR catalyst. The results show that significant PM reduction occurs in the SCR catalyst even during high rates of urea dosage. Analysis of the PM indicates that residual SOF is burned up in the SCR catalyst.

  12. The pulsed linear induction motor concept for high-speed trains

    SciTech Connect

    Turman, B.N.; Marder, B.M.; Rohwein, G.J.; Aeschliman, D.P.; Kelley, J.B.; Cowan, M.; Zimmerman, R.M.

    1995-06-01

    The SERAPBIM (SEgmented RAil PHased Induction Motor) concept is a linear induction motor concept which uses rapidly-pulsed magnetic fields and a segmented reaction rail, as opposed to low-frequency fields and continuous reaction rails found in conventional linear induction motors. These improvements give a high-traction, compact, and efficient linear motor that has potential for advanced high speed rail propulsion. In the SERAPBIM concept, coils on the vehicle push against a segmented aluminum rail, which is mounted on the road bed. Current is pulsed as the coils cross an edge of the segmented rail, inducing surface currents which repel the coil. The coils must be pulsed in synchronization with the movement by reaction rail segments. This is provided by a sense-and-fire circuit that controls the pulsing of the power modulators. Experiments were conducted to demonstrate the feasibility of the pulsed induction motor and to collect data that could be used for scaling calculations. A 14.4 kg aluminum plate was accelerated down a 4 m track to speeds of over 15 m/sec with peak thrust up to 18 kN per coilset. For a trainset capable of 200 mph speed, the SERAPHIM concept design is based on coils which are each capable of producing up to 3.5 kN thrust, and 30 coil pairs are mounted on each power car. Two power cars, one at each end of the train, provide 6 MW from two gas turbine prime power units. The thrust is about 210.000 N and is essentially constant up to 200 km/hr since wheel slippage does not limit thrust as with conventional wheeled propulsion. A key component of the SERAPHIM concept is the use of passive wheel-on-rah support for the high speed vehicle. Standard steel wheels are capable of handling over 200 mph. The SERAPHIM cost is comparable to that for steel-wheel high-speed rail, and about 10% to 25% of the projected costs for a comparable Maglev system.

  13. To authorize the use of certain rail relocation funding for high-speed rail projects.

    THOMAS, 112th Congress

    Rep. Johnson, Timothy V. [R-IL-15

    2011-10-03

    House - 10/04/2011 Referred to the Subcommittee on Railroads, Pipelines, and Hazardous Materials. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  14. High speed multiwire photon camera

    NASA Technical Reports Server (NTRS)

    Lacy, Jeffrey L. (Inventor)

    1991-01-01

    An improved multiwire proportional counter camera having particular utility in the field of clinical nuclear medicine imaging. The detector utilizes direct coupled, low impedance, high speed delay lines, the segments of which are capacitor-inductor networks. A pile-up rejection test is provided to reject confused events otherwise caused by multiple ionization events occuring during the readout window.

  15. High speed multiwire photon camera

    NASA Technical Reports Server (NTRS)

    Lacy, Jeffrey L. (Inventor)

    1989-01-01

    An improved multiwire proportional counter camera having particular utility in the field of clinical nuclear medicine imaging. The detector utilizes direct coupled, low impedance, high speed delay lines, the segments of which are capacitor-inductor networks. A pile-up rejection test is provided to reject confused events otherwise caused by multiple ionization events occurring during the readout window.

  16. Rail-accelerator development for ultra-high-pressure research

    SciTech Connect

    Hawke, R.S.; Nellis, W.J.; Rego, J.; Susoeff, A.R.; Newman, G.H.

    1983-09-14

    During the last year, we have begun detailed development of a railgun launcher and power source. We are developing a launcher with a gas injector. The injector accelerates the projectile to more than 1 km/s reducing the dwell time of the plasma arc and the erosion of the rails. The injected projectile, with a fuse, also serves as the main switch in the power supply circuit. Current pulse shaping is used to control the applied stress to the projectile and launcher. Results of experiments with the new system will be reported and compared to computer simulations.

  17. Rail accelerator development for ultra-high pressure research

    SciTech Connect

    Hawke, R.S.; Nellis, W.J.; Rego, J.; Susoeff, A.R.; Newman, G.H.

    1983-09-20

    The Lawrence Livermore National Laboratory is currently developing a rail accelerator system for launching hypervelocity projectiles suitable for ultrahigh pressure shockwave research. The primary goal is to accelerate 1 g projectiles with disk impactors to velocities in excess of 12 km/s and generate uniform, planar shockwaves at pressures above 0.5 TPa (5 Mbar) in metal targets. In order to generate precisely controlled impacts and shockwaves, several strigent requirements are imposed on the railgun system. During the last year, we have begun detailed development of a railgun launcher and power source. We are developing a launcher with a gas injector. The injector accelerates the projectile to more than 1 km/s reducing the dwell time of the plasma arc and the erosion of the rails. The injected projectile, with a fuse, also serves as the main switch in the power supply circuit. Current pulse shaping is used to control the applied stress to the projectile and launcher. Results of experiments with the new system will be reported and compared to computer simulations.

  18. Rail accelerator development for ultra-high pressure research

    SciTech Connect

    Hawke, R.S.; Nellis, W.J.

    1984-03-01

    The Lawrence Livermore National Laboratory is currently developing a rail accelerator system for launching hypervelocity projectiles suitable for ultrahigh pressure shockwave research. The primary goal is to accelerate 1 g projectiles with disk impactors to velocities in excess of 12 km/s and generate uniform, planar shockwaves at pressures above 0.5 TPa (5 Mbar) in metal targets. In order to generate precisely controlled impacts and shockwaves, several stringent requirements are imposed on the railgun system. During the last year, detailed development of a railgun launcher and power source has begun. A launcher with a gas injector is being developed. The injector accelerates the projectile to more than 1 km/s reducing the dwell time of the plasma arc and the erosion of the rails. The injected projectile, with a fuse, also serves as the main switch in the power supply circuit. Current pulse shaping is used to control the applied stress to the projectile and launcher. Results of experiments with the new system are reported and compared to computer simulations.

  19. Experiments on high speed ejectors

    NASA Technical Reports Server (NTRS)

    Wu, J. J.

    1986-01-01

    Experimental studies were conducted to investigate the flow and the performance of thrust augmenting ejectors for flight Mach numbers in the range of 0.5 to 0.8, primary air stagnation pressures up to 107 psig (738 kPa), and primary air stagnation temperatures up to 1250 F (677 C). The experiment verified the existence of the second solution ejector flow, where the flow after complete mixing is supersonic. Thrust augmentation in excess of 1.2 was demonstrated for both hot and cold primary jets. The experimental ejector performed better than the corresponding theoretical optimal first solution ejector, where the mixed flow is subsonic. Further studies are required to realize the full potential of the second solution ejector. The research program was started by the Flight Dynamics Research Corporation (FDRC) to investigate the characteristic of a high speed ejector which augments thrust of a jet at high flight speeds.

  20. Small Scale High Speed Turbomachinery

    NASA Technical Reports Server (NTRS)

    London, Adam P. (Inventor); Droppers, Lloyd J. (Inventor); Lehman, Matthew K. (Inventor); Mehra, Amitav (Inventor)

    2015-01-01

    A small scale, high speed turbomachine is described, as well as a process for manufacturing the turbomachine. The turbomachine is manufactured by diffusion bonding stacked sheets of metal foil, each of which has been pre-formed to correspond to a cross section of the turbomachine structure. The turbomachines include rotating elements as well as static structures. Using this process, turbomachines may be manufactured with rotating elements that have outer diameters of less than four inches in size, and/or blading heights of less than 0.1 inches. The rotating elements of the turbomachines are capable of rotating at speeds in excess of 150 feet per second. In addition, cooling features may be added internally to blading to facilitate cooling in high temperature operations.

  1. High Speed Photometry for BUSCA

    NASA Astrophysics Data System (ADS)

    Cordes, O.; Reif, K.

    The camera BUSCA (Bonn University Simultaneous CAmera) is a standard instrument at the 2.2m telescope at Calar Alto Observatory (Spain) since 2001. At the moment some modifications of BUSCA are planned and partially realised. One major goal is the replacement of the old thick CCDs in the blue, yellow-green, and near-infrared channels. The newer CCDs have better cosmetics and performance in sensitivity. The other goal is to replace the old "Heidelberg"-style controller with a newly designed controller with the main focus on high-speed readout and on an advanced windowing mechanism. We present a theoretical analysis of the new controller design and its advantage in high speed photometry of rapidly pulsating stars. As an example PG1605+072 was chosen which was observed with BUSCA before in 2001 and 2002.

  2. High-speed rotorcraft propulsion

    NASA Technical Reports Server (NTRS)

    Rutherford, John W.; Fitzpatrick, Robert E.

    1991-01-01

    Recently completed high-speed rotorcraft design studies for NASA provide the basis to assess technology needs for the development of these aircraft. Preliminary analysis of several concepts possessing helicopter-like hover characteristics and cruise capabilities in the 450 knot regime, led to the selection of two concepts for further study. The concepts selected included the Rotor/Wing and the Tilt Wing. The two unique concepts use turbofan and turboshaft engines respectively. Designs, based on current technology for each, established a baseline configuration from which technology trade studies could be conducted. Propulsion technology goals from the IHPTET program established the advanced technolgy year. Due to high-speed requirements, each concept possesses its own unique propulsion challenges. Trade studies indicate that achieving th IHPTET Phase III goals significantly improves the effectiveness of both concepts. Increased engine efficiency is particularly important to VTOL aircraft by reducing gross weight.

  3. High-speed code validation

    NASA Technical Reports Server (NTRS)

    Barnwell, Richard W.; Rogers, R. Clayton; Pittman, James L.; Dwoyer, Douglas L.

    1987-01-01

    The topics are presented in viewgraph form and include the following: NFL body experiment; high-speed validation problems; 3-D Euler/Navier-Stokes inlet code; two-strut inlet configuration; pressure contours in two longitudinal planes; sidewall pressure distribution; pressure distribution on strut inner surface; inlet/forebody tests in 60 inch helium tunnel; pressure distributions on elliptical missile; code validations; small scale test apparatus; CARS nonintrusive measurements; optimized cone-derived waverider study; etc.

  4. High Speed Holographic Movie Camera

    NASA Astrophysics Data System (ADS)

    Hentschel, W.; Lauterborn, W.

    1985-08-01

    A high speed holographic movie camera system has been developed to investigate the dynamic behavior of cavitation bubbles in liquids. As a light source for holography, a high power multiply cavity-dumped argonion laser is used to record very long hologram series with framing rates up to 300 kHz. For separating successively recorded holograms, two spatial multiplexing techniques are applied simultaneously: rotation of the holographic plate or film and acousto-optic beam deflection. With the combination of these two techniques we achieve up to 4000 single holograms in one series.

  5. High Speed Holographic Movie Camera

    NASA Astrophysics Data System (ADS)

    Hentschel, W.; Lauterborn, W.

    1985-02-01

    A high speed holographic movie camera system has been developed in our laboratories at the Third Physical Institute of the University of Gdttingen. As a light source for holography a high power multiply cavity-dumped argonion laser is used to record very long hologram series with framing rates up to 300 kHz. For separating successively recorded holograms two spatial multiplexing techniques are applied simultaneously: rotating of the holographic plate or film and acousto-optic beam deflection. With the combination of these two techniques we achieve up to 4000 single holograms in one series.

  6. High-Speed TCP Testing

    NASA Technical Reports Server (NTRS)

    Brooks, David E.; Gassman, Holly; Beering, Dave R.; Welch, Arun; Hoder, Douglas J.; Ivancic, William D.

    1999-01-01

    Transmission Control Protocol (TCP) is the underlying protocol used within the Internet for reliable information transfer. As such, there is great interest to have all implementations of TCP efficiently interoperate. This is particularly important for links exhibiting long bandwidth-delay products. The tools exist to perform TCP analysis at low rates and low delays. However, for extremely high-rate and lone-delay links such as 622 Mbps over geosynchronous satellites, new tools and testing techniques are required. This paper describes the tools and techniques used to analyze and debug various TCP implementations over high-speed, long-delay links.

  7. Quiet High-Speed Fan

    NASA Technical Reports Server (NTRS)

    Lieber, Lysbeth; Repp, Russ; Weir, Donald S.

    1996-01-01

    A calibration of the acoustic and aerodynamic prediction methods was performed and a baseline fan definition was established and evaluated to support the quiet high speed fan program. A computational fluid dynamic analysis of the NASA QF-12 Fan rotor, using the DAWES flow simulation program was performed to demonstrate and verify the causes of the relatively poor aerodynamic performance observed during the fan test. In addition, the rotor flowfield characteristics were qualitatively compared to the acoustic measurements to identify the key acoustic characteristics of the flow. The V072 turbofan source noise prediction code was used to generate noise predictions for the TFE731-60 fan at three operating conditions and compared to experimental data. V072 results were also used in the Acoustic Radiation Code to generate far field noise for the TFE731-60 nacelle at three speed points for the blade passage tone. A full 3-D viscous flow simulation of the current production TFE731-60 fan rotor was performed with the DAWES flow analysis program. The DAWES analysis was used to estimate the onset of multiple pure tone noise, based on predictions of inlet shock position as a function of the rotor tip speed. Finally, the TFE731-60 fan rotor wake structure predicted by the DAWES program was used to define a redesigned stator with the leading edge configured to minimize the acoustic effects of rotor wake / stator interaction, without appreciably degrading performance.

  8. High-speed phosphor thermometry.

    PubMed

    Fuhrmann, N; Baum, E; Brübach, J; Dreizler, A

    2011-10-01

    Phosphor thermometry is a semi-invasive surface temperature measurement technique utilising the luminescence properties of doped ceramic materials. Typically, these phosphor materials are coated onto the object of interest and are excited by a short UV laser pulse. Up to now, primarily Q-switched laser systems with repetition rates of 10 Hz were employed for excitation. Accordingly, this diagnostic tool was not applicable to resolve correlated temperature transients at time scales shorter than 100 ms. This contribution reports on the first realisation of a high-speed phosphor thermometry system employing a highly repetitive laser in the kHz regime and a fast decaying phosphor. A suitable material was characterised regarding its temperature lifetime characteristic and its measurement precision. Additionally, the influence of laser power on the phosphor coating was investigated in terms of heating effects. A demonstration of this high-speed technique has been conducted inside the thermally highly transient system of an optically accessible internal combustion engine. Temperatures have been measured with a repetition rate of 6 kHz corresponding to one sample per crank angle degree at 1000 rpm.

  9. High-speed phosphor thermometry

    NASA Astrophysics Data System (ADS)

    Fuhrmann, N.; Baum, E.; Brübach, J.; Dreizler, A.

    2011-10-01

    Phosphor thermometry is a semi-invasive surface temperature measurement technique utilising the luminescence properties of doped ceramic materials. Typically, these phosphor materials are coated onto the object of interest and are excited by a short UV laser pulse. Up to now, primarily Q-switched laser systems with repetition rates of 10 Hz were employed for excitation. Accordingly, this diagnostic tool was not applicable to resolve correlated temperature transients at time scales shorter than 100 ms. This contribution reports on the first realisation of a high-speed phosphor thermometry system employing a highly repetitive laser in the kHz regime and a fast decaying phosphor. A suitable material was characterised regarding its temperature lifetime characteristic and its measurement precision. Additionally, the influence of laser power on the phosphor coating was investigated in terms of heating effects. A demonstration of this high-speed technique has been conducted inside the thermally highly transient system of an optically accessible internal combustion engine. Temperatures have been measured with a repetition rate of 6 kHz corresponding to one sample per crank angle degree at 1000 rpm.

  10. High speed quantitative digital microscopy

    NASA Technical Reports Server (NTRS)

    Castleman, K. R.; Price, K. H.; Eskenazi, R.; Ovadya, M. M.; Navon, M. A.

    1984-01-01

    Modern digital image processing hardware makes possible quantitative analysis of microscope images at high speed. This paper describes an application to automatic screening for cervical cancer. The system uses twelve MC6809 microprocessors arranged in a pipeline multiprocessor configuration. Each processor executes one part of the algorithm on each cell image as it passes through the pipeline. Each processor communicates with its upstream and downstream neighbors via shared two-port memory. Thus no time is devoted to input-output operations as such. This configuration is expected to be at least ten times faster than previous systems.

  11. A high speed sequential decoder

    NASA Technical Reports Server (NTRS)

    Lum, H., Jr.

    1972-01-01

    The performance and theory of operation for the High Speed Hard Decision Sequential Decoder are delineated. The decoder is a forward error correction system which is capable of accepting data from binary-phase-shift-keyed and quadriphase-shift-keyed modems at input data rates up to 30 megabits per second. Test results show that the decoder is capable of maintaining a composite error rate of 0.00001 at an input E sub b/N sub o of 5.6 db. This performance has been obtained with minimum circuit complexity.

  12. High speed holographic digital recorder.

    PubMed

    Roberts, H N; Watkins, J W; Johnson, R H

    1974-04-01

    Concepts, feasibility experiments, and key component developments are described for a holographic digital record/reproduce system with the potential for 1.0 Gbit/sec rates and higher. Record rates of 500 Mbits/sec have been demonstrated with a ten-channel acoustooptic modulator array and a mode-locked, cavity-dumped argon-ion laser. Acoustooptic device technology has been advanced notably during the development of mode lockers, cavity dumpers, beam deflectors, and multichannel modulator arrays. The development of high speed multichannel photodetector arrays for the readout subsystem requires special attention. The feasibility of 1.0 Gbits/sec record rates has been demonstrated.

  13. Flexible high-speed CODEC

    NASA Technical Reports Server (NTRS)

    Segallis, Greg P.; Wernlund, Jim V.; Corry, Glen

    1993-01-01

    This report is prepared by Harris Government Communication Systems Division for NASA Lewis Research Center under contract NAS3-25087. It is written in accordance with SOW section 4.0 (d) as detailed in section 2.6. The purpose of this document is to provide a summary of the program, performance results and analysis, and a technical assessment. The purpose of this program was to develop a flexible, high-speed CODEC that provides substantial coding gain while maintaining bandwidth efficiency for use in both continuous and bursted data environments for a variety of applications.

  14. High speed quantitative digital microscopy

    NASA Technical Reports Server (NTRS)

    Castleman, K. R.; Price, K. H.; Eskenazi, R.; Ovadya, M. M.; Navon, M. A.

    1984-01-01

    Modern digital image processing hardware makes possible quantitative analysis of microscope images at high speed. This paper describes an application to automatic screening for cervical cancer. The system uses twelve MC6809 microprocessors arranged in a pipeline multiprocessor configuration. Each processor executes one part of the algorithm on each cell image as it passes through the pipeline. Each processor communicates with its upstream and downstream neighbors via shared two-port memory. Thus no time is devoted to input-output operations as such. This configuration is expected to be at least ten times faster than previous systems.

  15. Remote Transmission at High Speed

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Omni and NASA Test Operations at Stennis entered a Dual-Use Agreement to develop the FOTR-125, a 125 megabit-per-second fiber-optic transceiver that allows accurate digital recordings over a great distance. The transceiver s fiber-optic link can be as long as 25 kilometers. This makes it much longer than the standard coaxial link, which can be no longer than 50 meters.The FOTR-125 utilizes laser diode transmitter modules and integrated receivers for the optical interface. Two transmitters and two receivers are employed at each end of the link with automatic or manual switchover to maximize the reliability of the communications link. NASA uses the transceiver in Stennis High-Speed Data Acquisition System (HSDAS). The HSDAS consists of several identical systems installed on the Center s test stands to process all high-speed data related to its propulsion test programs. These transceivers allow the recorder and HSDAS controls to be located in the Test Control Center in a remote location while the digitizer is located on the test stand.

  16. Sound transmission loss of windows on high speed trains

    NASA Astrophysics Data System (ADS)

    Zhang, Yumei; Xiao, Xinbiao; Thompson, David; Squicciarini, Giacomo; Wen, Zefeng; Li, Zhihui; Wu, Yue

    2016-09-01

    The window is one of the main components of the high speed train car body structure through which noise can be transmitted. To study the windows’ acoustic properties, the vibration of one window of a high speed train has been measured for a running speed of 250 km/h. The corresponding interior noise and the noise in the wheel-rail area have been measured simultaneously. The experimental results show that the window vibration velocity has a similar spectral shape to the interior noise. Interior noise source identification further indicates that the window makes a contribution to the interior noise. Improvement of the window's Sound Transmission Loss (STL) can reduce the interior noise from this transmission path. An STL model of the window is built based on wave propagation and modal superposition methods. From the theoretical results, the window's STL property is studied and several factors affecting it are investigated, which provide indications for future low noise design of high speed train windows.

  17. High Speed Detection and Characterization of Defects in the Railhead

    NASA Astrophysics Data System (ADS)

    Edwards, R. S.; Fan, Y.; Dixon, S.

    2007-03-01

    In the UK, changing usage patterns for the rail network mean that rolling contact fatigue (RCF) in the railhead is an increasingly urgent problem. Current ultrasonic testing techniques have limitations in terms of testing speed and ability to reliably detect such defects. A different approach to the problem is to use ultrasonic surface waves generated and detected in a pitch-catch manner, thus simplifying the probe to detect surface defects such as RCF and to ignore deeper bulk defects. By using a pitch-catch configuration several of the speed limitations are removed; the probes are free to move as soon as each signal has been generated, without the need to wait for detection of the signal, and separation of the probes can be increased to allow for limited pulse repetition rates. Better reliability of detection for surface defects is also found, with the transmitted signal being dominated by the deepest surface-breaking defect present between the probes. We present details of a new high speed system, consisting of several electro-magnetic acoustic transducers (EMATs) to generate and detect the signals, with a high speed A-D system which has the ability to detect, window and FFT time signals and analyse the FFT to give a cut-off frequency within 1 ms, giving a depth for any defects present between the probes.

  18. High-Speed Schlieren Movies of Decelerators at Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    1960-01-01

    High-Speed Schlieren Movies of Decelerators at Supersonic Speeds. Tests were conducted on several types of porous parachutes, a paraglider, and a simulated retrorocket. Mach numbers ranged from 1.8-3.0, porosity from 20-80 percent, and camera speeds from 1680-3000 feet per second (fps) in trials with porous parachutes. Trials of reefed parachutes were conducted at Mach number 2.0 and reefing of 12-33 percent at camera speeds of 600 fps. A flexible parachute with an inflatable ring in the periphery of the canopy was tested at Reynolds number 750,000 per foot, Mach number 2.85, porosity of 28 percent, and camera speed of 36oo fps. A vortex-ring parachute was tested at Mach number 2.2 and camera speed of 3000 fps. The paraglider, with a sweepback of 45 degrees at an angle of attack of 45 degrees was tested at Mach number 2.65, drag coefficient of 0.200, and lift coefficient of 0.278 at a camera speed of 600 fps. A cold air jet exhausting upstream from the center of a bluff body was used to simulate a retrorocket. The free-stream Mach number was 2.0, free-stream dynamic pressure was 620 lb/sq ft, jet-exit static pressure ratio was 10.9, and camera speed was 600 fps. [Entire movie available on DVD from CASI as Doc ID 20070030973. Contact help@sti.nasa.gov

  19. High-speed data search

    NASA Technical Reports Server (NTRS)

    Driscoll, James N.

    1994-01-01

    The high-speed data search system developed for KSC incorporates existing and emerging information retrieval technology to help a user intelligently and rapidly locate information found in large textual databases. This technology includes: natural language input; statistical ranking of retrieved information; an artificial intelligence concept called semantics, where 'surface level' knowledge found in text is used to improve the ranking of retrieved information; and relevance feedback, where user judgements about viewed information are used to automatically modify the search for further information. Semantics and relevance feedback are features of the system which are not available commercially. The system further demonstrates focus on paragraphs of information to decide relevance; and it can be used (without modification) to intelligently search all kinds of document collections, such as collections of legal documents medical documents, news stories, patents, and so forth. The purpose of this paper is to demonstrate the usefulness of statistical ranking, our semantic improvement, and relevance feedback.

  20. Flexible High Speed Codec (FHSC)

    NASA Technical Reports Server (NTRS)

    Segallis, G. P.; Wernlund, J. V.

    1991-01-01

    The ongoing NASA/Harris Flexible High Speed Codec (FHSC) program is described. The program objectives are to design and build an encoder decoder that allows operation in either burst or continuous modes at data rates of up to 300 megabits per second. The decoder handles both hard and soft decision decoding and can switch between modes on a burst by burst basis. Bandspreading is low since the code rate is greater than or equal to 7/8. The encoder and a hard decision decoder fit on a single application specific integrated circuit (ASIC) chip. A soft decision applique is implemented using 300 K emitter coupled logic (ECL) which can be easily translated to an ECL gate array.

  1. Preliminary study of high-speed machining

    SciTech Connect

    Jordan, R.E.

    1980-07-01

    The feasibility of a high speed machining process has been established for application to Bendix aluminum products, based upon information gained through visits to existing high speed machining facilities and by the completion of a representative Bendix part using this process. The need for an experimental high speed machining capability at Bendix for further process evaluation is established.

  2. High speed sampler and demultiplexer

    DOEpatents

    McEwan, T.E.

    1995-12-26

    A high speed sampling demultiplexer based on a plurality of sampler banks, each bank comprising a sample transmission line for transmitting an input signal, a strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates at respective positions along the sample transmission line for sampling the input signal in response to the strobe signal. Strobe control circuitry is coupled to the plurality of banks, and supplies a sequence of bank strobe signals to the strobe transmission lines in each of the plurality of banks, and includes circuits for controlling the timing of the bank strobe signals among the banks of samplers. Input circuitry is included for supplying the input signal to be sampled to the plurality of sample transmission lines in the respective banks. The strobe control circuitry can repetitively strobe the plurality of banks of samplers such that the banks of samplers are cycled to create a long sample length. Second tier demultiplexing circuitry is coupled to each of the samplers in the plurality of banks. The second tier demultiplexing circuitry senses the sample taken by the corresponding sampler each time the bank in which the sampler is found is strobed. A plurality of such samples can be stored by the second tier demultiplexing circuitry for later processing. Repetitive sampling with the high speed transient sampler induces an effect known as ``strobe kickout``. The sample transmission lines include structures which reduce strobe kickout to acceptable levels, generally 60 dB below the signal, by absorbing the kickout pulses before the next sampling repetition. 16 figs.

  3. High speed sampler and demultiplexer

    DOEpatents

    McEwan, Thomas E.

    1995-01-01

    A high speed sampling demultiplexer based on a plurality of sampler banks, each bank comprising a sample transmission line for transmitting an input signal, a strobe transmission line for transmitting a strobe signal, and a plurality of sampling gates at respective positions along the sample transmission line for sampling the input signal in response to the strobe signal. Strobe control circuitry is coupled to the plurality of banks, and supplies a sequence of bank strobe signals to the strobe transmission lines in each of the plurality of banks, and includes circuits for controlling the timing of the bank strobe signals among the banks of samplers. Input circuitry is included for supplying the input signal to be sampled to the plurality of sample transmission lines in the respective banks. The strobe control circuitry can repetitively strobe the plurality of banks of samplers such that the banks of samplers are cycled to create a long sample length. Second tier demultiplexing circuitry is coupled to each of the samplers in the plurality of banks. The second tier demultiplexing circuitry senses the sample taken by the corresponding sampler each time the bank in which the sampler is found is strobed. A plurality of such samples can be stored by the second tier demultiplexing circuitry for later processing. Repetitive sampling with the high speed transient sampler induces an effect known as "strobe kickout". The sample transmission lines include structures which reduce strobe kickout to acceptable levels, generally 60 dB below the signal, by absorbing the kickout pulses before the next sampling repetition.

  4. ADVANCED HIGH SPEED PROGRAMMABLE PREFORMING

    SciTech Connect

    Norris Jr, Robert E; Lomax, Ronny D; Xiong, Fue; Dahl, Jeffrey S; Blanchard, Patrick J

    2010-01-01

    Polymer-matrix composites offer greater stiffness and strength per unit weight than conventional materials resulting in new opportunities for lightweighting of automotive and heavy vehicles. Other benefits include design flexibility, less corrosion susceptibility, and the ability to tailor properties to specific load requirements. However, widespread implementation of structural composites requires lower-cost manufacturing processes than those that are currently available. Advanced, directed-fiber preforming processes have demonstrated exceptional value for rapid preforming of large, glass-reinforced, automotive composite structures. This is due to process flexibility and inherently low material scrap rate. Hence directed fiber performing processes offer a low cost manufacturing methodology for producing preforms for a variety of structural automotive components. This paper describes work conducted at the Oak Ridge National Laboratory (ORNL), focused on the development and demonstration of a high speed chopper gun to enhance throughput capabilities. ORNL and the Automotive Composites Consortium (ACC) revised the design of a standard chopper gun to expand the operational envelope, enabling delivery of up to 20kg/min. A prototype unit was fabricated and used to demonstrate continuous chopping of multiple roving at high output over extended periods. In addition fiber handling system modifications were completed to sustain the high output the modified chopper affords. These hardware upgrades are documented along with results of process characterization and capabilities assessment.

  5. 78 FR 28940 - Environmental Impact Statement for the Atlanta to Charlotte Portion of the Southeast High Speed...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-16

    ... between Atlanta, GA and Charlotte, NC, along the Southeast High-Speed Rail Corridor (SEHSR) as designated... site: www.dot.ga.gov/AtlantaCharlotteHSR . ADDRESSES: Comments related to the scope of the study may be mailed to Glenn Bowman, PE, State Environmental Administrator, 600 West Peachtree Street NW., Atlanta,...

  6. Hypereutectoid high-speed steels

    SciTech Connect

    Kremnev, L.S.

    1986-01-01

    Half of the tungsten and molybdenum contained in R6M5 and R18 steels is concentrated in the undissolved eutectic carbides hindering austenitic grain gowth in hardening and providing the necessary strength and impact strength. This article describes the tungsten-free low-alloy high-speed steel 11M5F with a chemical composition of 1.03-1.10% C, 5.2-5.7% Mo, 3.8-4.2% Cr, 1.3-1.7% V, 0.3-0.6% Si, and 0.3% Ce. The properties of 11M5F and R6M5 steels are examined and compared. The results of production and laboratory tests of the cutting properties of tools of the steels developed showed their high effectiveness, especially of 11M5F steel with 1% A1. The life of tools of the tungsten-free steels is two or three times greater than the life of tools of R6M5 steel.

  7. High speed imager test station

    DOEpatents

    Yates, G.J.; Albright, K.L.; Turko, B.T.

    1995-11-14

    A test station enables the performance of a solid state imager (herein called a focal plane array or FPA) to be determined at high image frame rates. A programmable waveform generator is adapted to generate clock pulses at determinable rates for clock light-induced charges from a FPA. The FPA is mounted on an imager header board for placing the imager in operable proximity to level shifters for receiving the clock pulses and outputting pulses effective to clock charge from the pixels forming the FPA. Each of the clock level shifters is driven by leading and trailing edge portions of the clock pulses to reduce power dissipation in the FPA. Analog circuits receive output charge pulses clocked from the FPA pixels. The analog circuits condition the charge pulses to cancel noise in the pulses and to determine and hold a peak value of the charge for digitizing. A high speed digitizer receives the peak signal value and outputs a digital representation of each one of the charge pulses. A video system then displays an image associated with the digital representation of the output charge pulses clocked from the FPA. In one embodiment, the FPA image is formatted to a standard video format for display on conventional video equipment. 12 figs.

  8. High speed imager test station

    DOEpatents

    Yates, George J.; Albright, Kevin L.; Turko, Bojan T.

    1995-01-01

    A test station enables the performance of a solid state imager (herein called a focal plane array or FPA) to be determined at high image frame rates. A programmable waveform generator is adapted to generate clock pulses at determinable rates for clock light-induced charges from a FPA. The FPA is mounted on an imager header board for placing the imager in operable proximity to level shifters for receiving the clock pulses and outputting pulses effective to clock charge from the pixels forming the FPA. Each of the clock level shifters is driven by leading and trailing edge portions of the clock pulses to reduce power dissipation in the FPA. Analog circuits receive output charge pulses clocked from the FPA pixels. The analog circuits condition the charge pulses to cancel noise in the pulses and to determine and hold a peak value of the charge for digitizing. A high speed digitizer receives the peak signal value and outputs a digital representation of each one of the charge pulses. A video system then displays an image associated with the digital representation of the output charge pulses clocked from the FPA. In one embodiment, the FPA image is formatted to a standard video format for display on conventional video equipment.

  9. High speed holographic cine-recorder

    NASA Astrophysics Data System (ADS)

    Snyder, Donald; Watts, David; Gordon, Joseph; Lysogorski, Charles; Powers, Aaron; Perry, John; Chenette, Eugene; Hudson, Roger; Young, Raymond

    2005-08-01

    Air Force Research Laboratory and North Dancer Labs researchers have completed the initial development and transition to operational use of a high-speed holographic movie system. This paper documents the first fully operational use of a novel and unique experimental capability for high-speed holographic movies and high-speed cinema interferometry. In this paper we document the initial experiments that were performed with the High Speed Holographic Recorder (HSHR) at the Munitions Directorate, Air Force Research Laboratory Site at Eglin, AFB, Florida. These experiments were performed to assess the possibilities for high-speed cine-laser holography combined with high-speed videography to document the formation and propagation of plumes of materials created by impact of high-speed projectiles. This paper details the development of the experimental procedures and initial results of this new tool. After successful integration and testing the system was delivered to Arnold Engineering Development Center.

  10. 8-Foot High Speed Tunnel

    NASA Technical Reports Server (NTRS)

    1936-01-01

    Control panel below the test section of the 8-Foot High Speed Tunnel (8-Foot HST). Authorized July 17, 1933, construction of the 8-Foot HST was paid for with funds from the Federal Public Works Administration. Manly Hood and Russell Robinson designed the unusual facility which could produce a 500 mph wind stream across an 8-Foot test section. The concrete shell was not part of the original design. Like most projects funded through New Deal programs, the PWA restricted the amount of money which could be spent on materials. The majority of funds were supposed to be expended on labor. Though originally, Hood and Robinson had planned a welded steel pressure vessel around the test section, PWA officials proposed the idea of concrete. This picture shows the test section inside the igloo-like structure with walls of 1-foot thick reinforced concrete. The thick walls were needed 'because of the Bernoulli effect, [which meant that] the text chamber had to withstand powerful, inwardly directed pressure. Operating personnel located inside the igloo were subjected to pressures equivalent to 10,000-foot altitude and had to wear oxygen masks and enter through airlocks. A heat exchanger removed the large quantities of heat generated by the big fan.'

  11. Experimental high-speed network

    NASA Astrophysics Data System (ADS)

    McNeill, Kevin M.; Klein, William P.; Vercillo, Richard; Alsafadi, Yasser H.; Parra, Miguel V.; Dallas, William J.

    1993-09-01

    Many existing local area networking protocols currently applied in medical imaging were originally designed for relatively low-speed, low-volume networking. These protocols utilize small packet sizes appropriate for text based communication. Local area networks of this type typically provide raw bandwidth under 125 MHz. These older network technologies are not optimized for the low delay, high data traffic environment of a totally digital radiology department. Some current implementations use point-to-point links when greater bandwidth is required. However, the use of point-to-point communications for a total digital radiology department network presents many disadvantages. This paper describes work on an experimental multi-access local area network called XFT. The work includes the protocol specification, and the design and implementation of network interface hardware and software. The protocol specifies the Physical and Data Link layers (OSI layers 1 & 2) for a fiber-optic based token ring providing a raw bandwidth of 500 MHz. The protocol design and implementation of the XFT interface hardware includes many features to optimize image transfer and provide flexibility for additional future enhancements which include: a modular hardware design supporting easy portability to a variety of host system buses, a versatile message buffer design providing 16 MB of memory, and the capability to extend the raw bandwidth of the network to 3.0 GHz.

  12. High speed all optical networks

    NASA Technical Reports Server (NTRS)

    Chlamtac, Imrich; Ganz, Aura

    1990-01-01

    An inherent problem of conventional point-to-point wide area network (WAN) architectures is that they cannot translate optical transmission bandwidth into comparable user available throughput due to the limiting electronic processing speed of the switching nodes. The first solution to wavelength division multiplexing (WDM) based WAN networks that overcomes this limitation is presented. The proposed Lightnet architecture takes into account the idiosyncrasies of WDM switching/transmission leading to an efficient and pragmatic solution. The Lightnet architecture trades the ample WDM bandwidth for a reduction in the number of processing stages and a simplification of each switching stage, leading to drastically increased effective network throughputs. The principle of the Lightnet architecture is the construction and use of virtual topology networks, embedded in the original network in the wavelength domain. For this construction Lightnets utilize the new concept of lightpaths which constitute the links of the virtual topology. Lightpaths are all-optical, multihop, paths in the network that allow data to be switched through intermediate nodes using high throughput passive optical switches. The use of the virtual topologies and the associated switching design introduce a number of new ideas, which are discussed in detail.

  13. High-speed pressure clamp.

    PubMed

    Besch, Stephen R; Suchyna, Thomas; Sachs, Frederick

    2002-10-01

    We built a high-speed, pneumatic pressure clamp to stimulate patch-clamped membranes mechanically. The key control element is a newly designed differential valve that uses a single, nickel-plated piezoelectric bending element to control both pressure and vacuum. To minimize response time, the valve body was designed with minimum dead volume. The result is improved response time and stability with a threefold decrease in actuation latency. Tight valve clearances minimize the steady-state air flow, permitting us to use small resonant-piston pumps to supply pressure and vacuum. To protect the valve from water contamination in the event of a broken pipette, an optical sensor detects water entering the valve and increases pressure rapidly to clear the system. The open-loop time constant for pressure is 2.5 ms for a 100-mmHg step, and the closed-loop settling time is 500-600 micros. Valve actuation latency is 120 micros. The system performance is illustrated for mechanically induced changes in patch capacitance.

  14. Rail safety and rail privatisation in Japan.

    PubMed

    Evans, Andrew W

    2010-07-01

    Over the period from 1980 to the present, the economic status of the main line railway systems in many developed countries has changed, by privatisation or economic deregulation or both. The principal aims of such changes have been to improve the economic performance of the railways, and not to change the safety performance. Nevertheless, it is recognised that changing the organisational structure of railways might affect safety. The empirical evidence of the effect of restructuring on safety is limited, both in railways and in other industries. This paper adds to the empirical evidence by analysing train accidents in Japan before and after the privatisation of the Japanese National Railways (JNR) in 1987. The paper finds that the JNR achieved downward trends in the mean number of train accidents per train-kilometre in the 16 years 1971-1986, and the paper takes the extrapolation of these favourable trends as the yardstick by which to judge the safety performance of the privatised railways. The paper finds that the privatised railway had fewer train accidents in total than this yardstick in 1987-2006. This finding applies whether or not the high-speed Shinkansen train operations are included. Thus there is no evidence that rail privatisation in Japan had an adverse effect on train accidents. The methods adopted and the results are similar to those previously found by the author for rail privatisation in Great Britain. Copyright 2010 Elsevier Ltd. All rights reserved.

  15. Rail damage in a solid-armature rail gun. Final report

    SciTech Connect

    Brassard, T.; Homan, C.G.

    1987-12-01

    Plasma-arc-drive rail guns operate by forming a high-temperature plasma behind the projectile using a thin metal fuze. These systems achieve the highest projectile velocities (about 12 km /sec), since the driving force includes a substantial plasma pressure as well as the electromagnetic or Lorentz force. Unfortunately, severe rail damage occurs primarily from the intense temperatures generated by the plasma arc and the wiping motion of the armature itself. The solid-armature gun replaces the plasma armature with a conducting metal armature. Since the plasma arcing is reduced or eliminated, the projectiles are accelerated mainly by the Lorentz force. Thus, solid armature rail guns operate at lower projectile velocities. The important tradeoff is that there is a substantial reduction in rail damage for metal armature projectiles. The elimination of the plasma force limits projectile velocities in the metal-armature rail guns. A more-subtle limit is the speed at which the commutation process can take place. Although the latter limit is still not well understood, experimental evidence indicates a commutation limit may occur near 6 to 7 km/sec. This velocity limit is still attractive for Army tactical missions for rail guns. The actual rail damage occurring with two types of metal armatures, wire brush contactors and monolithic metal contactors, and new developments in barrel technology, such as superconducting augmentation, are presented in this report.

  16. High-speed Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Ackeret, J

    1936-01-01

    Wind tunnel construction and design is discussed especially in relation to subsonic and supersonic speeds. Reynolds Numbers and the theory of compressible flows are also taken into consideration in designing new tunnels.

  17. High speed imaging - An important industrial tool

    NASA Technical Reports Server (NTRS)

    Moore, Alton; Pinelli, Thomas E.

    1986-01-01

    High-speed photography, which is a rapid sequence of photographs that allow an event to be analyzed through the stoppage of motion or the production of slow-motion effects, is examined. In high-speed photography 16, 35, and 70 mm film and framing rates between 64-12,000 frames per second are utilized to measure such factors as angles, velocities, failure points, and deflections. The use of dual timing lamps in high-speed photography and the difficulties encountered with exposure and programming the camera and event are discussed. The application of video cameras to the recording of high-speed events is described.

  18. Joint Access Control Based on Access Ratio and Resource Utilization for High-Speed Railway Communications

    NASA Astrophysics Data System (ADS)

    Zhou, Yuzhe; Ai, Bo

    2015-05-01

    The fast development of high-speed rails makes people's life more and more convenient. However, provisioning of quality of service of multimedia applications for users on the high-speed train is a critical task for wireless communications. Therefore, new solutions are desirable to be found to address this kind of problem. Current researches mainly focus on providing seamless broadband wireless access for high-speed mobile terminals. In this paper, an algorithm to calculate the optimal resource reservation fraction of handovers is proposed. A joint access control scheme for high-speed railway communication handover scenario is proposed. Metrics of access ratio and resource utilization ratio are considered jointly in the analysis and the performance evaluation. Simulation results show that the proposed algorithm and the scheme improve quality of service compared with other conventional schemes.

  19. High-Speed Ring Bus

    NASA Technical Reports Server (NTRS)

    Wysocky, Terry; Kopf, Edward, Jr.; Katanyoutananti, Sunant; Steiner, Carl; Balian, Harry

    2010-01-01

    The high-speed ring bus at the Jet Propulsion Laboratory (JPL) allows for future growth trends in spacecraft seen with future scientific missions. This innovation constitutes an enhancement of the 1393 bus as documented in the Institute of Electrical and Electronics Engineers (IEEE) 1393-1999 standard for a spaceborne fiber-optic data bus. It allows for high-bandwidth and time synchronization of all nodes on the ring. The JPL ring bus allows for interconnection of active units with autonomous operation and increased fault handling at high bandwidths. It minimizes the flight software interface with an intelligent physical layer design that has few states to manage as well as simplified testability. The design will soon be documented in the AS-1393 standard (Serial Hi-Rel Ring Network for Aerospace Applications). The framework is designed for "Class A" spacecraft operation and provides redundant data paths. It is based on "fault containment regions" and "redundant functional regions (RFR)" and has a method for allocating cables that completely supports the redundancy in spacecraft design, allowing for a complete RFR to fail. This design reduces the mass of the bus by incorporating both the Control Unit and the Data Unit in the same hardware. The standard uses ATM (asynchronous transfer mode) packets, standardized by ITU-T, ANSI, ETSI, and the ATM Forum. The IEEE-1393 standard uses the UNI form of the packet and provides no protection for the data portion of the cell. The JPL design adds optional formatting to this data portion. This design extends fault protection beyond that of the interconnect. This includes adding protection to the data portion that is contained within the Bus Interface Units (BIUs) and by adding to the signal interface between the Data Host and the JPL 1393 Ring Bus. Data transfer on the ring bus does not involve a master or initiator. Following bus protocol, any BIU may transmit data on the ring whenever it has data received from its host. There

  20. High speed nano-metrology

    SciTech Connect

    Humphris, Andrew D. L.; Zhao Bin; Catto, David; Kohli, Priyanka; Howard-Knight, Jeremy P.; Hobbs, Jamie K.

    2011-04-15

    For manufacturing at the nanometre scale a method for rapid and accurate measurement of the resultant functional devices is required. Although atomic force microscopy (AFM) has the requisite spatial resolution, it is severely limited in scan speed, the resolution and repeatability of vertical and lateral measurements being degraded when speed is increased. Here we present a new approach to AFM that makes a direct and feedback-independent measurement of surface height using a laser interferometer focused onto the back of the AFM tip. Combining this direct height measurement with a passive, feedback-free method for maintaining tip-sample contact removes the constraint on scan speed that comes from the bandwidth of the z-feedback loop. Conventional laser reflection detection is used for feedback control, which now plays the role of minimising tip-sample forces, rather than producing the sample topography. Using the system in conjunction with a rapid scanner, true height images are obtained with areas up to (36 x 36) {mu}m{sup 2} at 1 image/second, suitable for in-line applications.

  1. New York state high-speed surface transportation study: Final report

    SciTech Connect

    Not Available

    1994-08-01

    In 1990, New York State Governor Mario M. Cuomo created an interagency task force under the leadership of Lt. Governor Stan Lundine to investigate the potential of high speed ground transportation (HSGT) systems. Building on information from previous agency activities, including consultant efforts contracted by the New York State Energy Research and Development Authority (NYSERDA), the New York State Thruway Authority (NYSTA), and in-house analyses performed by New York State Department of Transportation (NYSDOT), the task force focused on the corridor between New York City and the Niagara Frontier. In December 1991, NYSERDA issued a contract for a study of high speed ground transportation options for New York State. The study`s objective was to assess potential rights-of-way, ridership, energy and environmental impacts, economic benefits, capital, operating, and maintenance costs, and financial viability of HSGT systems. This study builds upon and supplements previous and on-going HSGT activities conducted by the members of the interagency task force. These activities include: Maglev Technical and Economic Feasibility Study (NYSERDA); Maglev Demonstration Site Investigation (NYSTA); and New York/Massachusetts High Speed Ground Transportation Study (NYSDOT). This study is intended to verify and refine previous information and analyses and provide supplemental information and insights to be used in determining if additional investigation and activities involving HSGT are desirable for New York State. This study evaluates HSGT technologies capable of speeds significantly higher than those achieved with the present rail system. Three HSGT categories are used in this study: incremental rail improvement, very high-speed rail, and Maglev.

  2. 3D shape reconstruction of rail and surface defect detection based on PMP

    NASA Astrophysics Data System (ADS)

    Duan, Fan; Lee, Jinlong; Luo, Lin; Gao, Xiaorong

    2016-09-01

    With the rapid development of high-speed and heavy-load in modern rail transit, the abrasion and surface defect of rail are getting serious, and the demand of measuring the rail shape and surface defect has been rising. Phase Measuring Profilometry (PMP), due to the good characters of non-contact, high precision, easy to control automatically etc., is often used for precise 3D shape reconstruction. In this paper, PMP technology and Stoilov phase shift algorithm are adopted, three deformed fringe patterns of rail are collected with fixed phase shift between them, and branch cut phase unwrapping algorithm is used, based on which the three-dimensional surface shape of the rail is reconstructed and the artificial surface flaws are restored and measured. This method provides a good reference for the precise online detection of the rail abrasion and surface defect.

  3. Lightweight, high speed bearing balls: A concept

    NASA Technical Reports Server (NTRS)

    Parker, R. J.

    1974-01-01

    Low mass bearing balls with hardened iron-plated surfaces can eliminate problems of low fatigue strength and flexure fatigue, and lead to increased life and reliability of high speed ball bearings. Low mass balls exert lower centrifugal forces on outer race of bearing thus eliminating detrimental effect of high speed operation.

  4. High Speed Video for Airborne Instrumentation Application

    NASA Technical Reports Server (NTRS)

    Tseng, Ting; Reaves, Matthew; Mauldin, Kendall

    2006-01-01

    A flight-worthy high speed color video system has been developed. Extensive system development and ground and environmental. testing hes yielded a flight qualified High Speed Video System (HSVS), This HSVS was initially used on the F-15B #836 for the Lifting Insulating Foam Trajectory (LIFT) project.

  5. Reducing Heating In High-Speed Cinematography

    NASA Technical Reports Server (NTRS)

    Slater, Howard A.

    1989-01-01

    Infrared-absorbing and infrared-reflecting glass filters simple and effective means for reducing rise in temperature during high-speed motion-picture photography. "Hot-mirror" and "cold-mirror" configurations, employed in projection of images, helps prevent excessive heating of scenes by powerful lamps used in high-speed photography.

  6. High-Speed Photography with Computer Control.

    ERIC Educational Resources Information Center

    Winters, Loren M.

    1991-01-01

    Describes the use of a microcomputer as an intervalometer for the control and timing of several flash units to photograph high-speed events. Applies this technology to study the oscillations of a stretched rubber band, the deceleration of high-speed projectiles in water, the splashes of milk drops, and the bursts of popcorn kernels. (MDH)

  7. High-Speed Photography with Computer Control.

    ERIC Educational Resources Information Center

    Winters, Loren M.

    1991-01-01

    Describes the use of a microcomputer as an intervalometer for the control and timing of several flash units to photograph high-speed events. Applies this technology to study the oscillations of a stretched rubber band, the deceleration of high-speed projectiles in water, the splashes of milk drops, and the bursts of popcorn kernels. (MDH)

  8. Dynamic simulation and safety evaluation of high-speed trains meeting in open air

    NASA Astrophysics Data System (ADS)

    Li, Songyan; Zheng, Zhijun; Yu, Jilin; Qian, Chunqiang

    2016-04-01

    Dynamic responses of a carriage under excitation with the German high-speed low-interference track spectrum together with the air pressure pulse generated as high-speed trains passing each other are investigated with a multi-body dynamics method. The variations of degrees of freedom (DOFs: horizontal movement, roll angle, and yaw angle), the lateral wheel-rail force, the derailment coefficient, and the rate of wheel load reduction with time when two carriages meet in open air are obtained and compared with the results of a single train travelling at specified speeds. Results show that the rate of wheel load reduction increases with the increase of train speed and meets some safety standard at a certain speed, but exceeding the value of the rate of wheel load reduction does not necessarily mean derailment. The evaluation standard of the rate of wheel load reduction is somewhat conservative and may be loosened. The pressure pulse has significant effects on the train DOFs, and the evaluations of these safety indexes are strongly suggested in practice. The pressure pulse has a limited effect on the derailment coefficient and the lateral wheel-rail force, and, thus, their further evaluations may be not necessary.

  9. Investigation of the effects of sleeper-passing impacts on the high-speed train

    NASA Astrophysics Data System (ADS)

    Wu, Xingwen; Cai, Wubin; Chi, Maoru; Wei, Lai; Shi, Huailong; Zhu, Minhao

    2015-12-01

    The sleeper-passing impact has always been considered negligible in normal conditions, while the experimental data obtained from a High-speed train in a cold weather expressed significant sleeper-passing impacts on the axle box, bogie frame and car body. Therefore, in this study, a vertical coupled vehicle/track dynamic model was developed to investigate the sleeper-passing impacts and its effects on the dynamic performance of the high-speed train. In the model, the dynamic model of vehicle is established with 10 degrees of freedom. The track model is formulated with two rails supported on the discrete supports through the finite element method. The contact forces between the wheel and rail are estimated using the non-linear Hertz contact theory. The parametric studies are conducted to analyse effects of both the vehicle speeds and the discrete support stiffness on the sleeper-passing impacts. The results show that the sleeper-passing impacts become extremely significant with the increased support stiffness of track, especially when the frequencies of sleeper-passing impacts approach to the resonance frequencies of wheel/track system. The damping of primary suspension can effectively lower the magnitude of impacts in the resonance speed ranges, but has little effect on other speed ranges. Finally, a more comprehensively coupled vehicle/track dynamic model integrating with a flexible wheel set is developed to discuss the sleeper-passing-induced flexible vibration of wheel set.

  10. Acoustic emission detection of rail defect based on wavelet transform and Shannon entropy

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Feng, Naizhang; Wang, Yan; Shen, Yi

    2015-03-01

    In order to detect cracks in railroad tracks, various experiments have been examined by Acoustic Emission (AE) method. However, little work has been done on studying rail defect detection at high speed. This paper presents a study on AE detection of rail defect at high speed based on rail-wheel test rig. Meanwhile, Wavelet Transform and Shannon entropy are employed to detect defects. Signals with and without defects are acquired, and characteristic frequencies from them at different speeds are analyzed. Based on appropriate decomposition level and Energy-to-Shannon entropy ratio, the optimal wavelet is selected. In order to suppress noise effects and ensure appropriate time resolution, the length of time window is investigated. Further, the characteristic frequency of time window is employed to detect defect. The results clearly illustrate that the proposed method can detect rail defect at high speed effectively.

  11. Role of the leader in the rail gun channel at high launching velocities

    NASA Astrophysics Data System (ADS)

    Zagorskii, A. V.; Katsnel'Son, S. S.; Pravdin, S. S.; Fomichev, V. P.

    1992-08-01

    An analysis of the performance of a number of rail guns indicates that one of the factors limiting the launching velocity is the formation of a leader. In experiments, the leader is usually formed as a result of a plasma breakdown between the dielectric projectile and the channel walls. This can be prevented by various technical means. However, at high launching velocities (5 km/s and greater) a leader may form as a result of a breakdown in the ionized gas in the wake of a strong shock wave ahead of the projectile. Further research is needed to find ways of preventing the formation of a leader in the latter case.

  12. High speed flow past wings

    NASA Technical Reports Server (NTRS)

    Norstrud, H.

    1973-01-01

    The analytical solution to the transonic small perturbation equation which describes steady compressible flow past finite wings at subsonic speeds can be expressed as a nonlinear integral equation with the perturbation velocity potential as the unknown function. This known formulation is substituted by a system of nonlinear algebraic equations to which various methods are applicable for its solution. Due to the presence of mathematical discontinuities in the flow solutions, however, a main computational difficulty was to ensure uniqueness of the solutions when local velocities on the wing exceeded the speed of sound. For continuous solutions this was achieved by embedding the algebraic system in an one-parameter operator homotopy in order to apply the method of parametric differentiation. The solution to the initial system of equations appears then as a solution to a Cauchy problem where the initial condition is related to the accompanying incompressible flow solution. In using this technique, however, a continuous dependence of the solution development on the initial data is lost when the solution reaches the minimum bifurcation point. A steepest descent iteration technique was therefore, added to the computational scheme for the calculation of discontinuous flow solutions. Results for purely subsonic flows and supersonic flows with and without compression shocks are given and compared with other available theoretical solutions.

  13. Analysis of the main trends in the development of rail production in Russia and abroad

    NASA Astrophysics Data System (ADS)

    Golovatenko, A. V.; Umansky, A. A.; Dorofeev, V. V.

    2016-09-01

    The present analysis reveals the main directions in the development of rail production in the world: the transition to rolling of rail sections using continuous group of universal stands, increase of the rails length, application of differentiated hardening of rails in different media. It is shown that the technological gap between the Russian metallurgical industry and the world's leading rail manufactures of the last decades was closed in 2013 -2014 when the new universal rolling mills at JSC “EVRAZ Consolidated West Siberian Metallurgical Plant” (“EVRAZ ZSMK”) and OJSC “Chelyabinsk Metallurgical Plant” (company “Mechel”) were launched. Currently, these steel enterprises provide complete import substitution of long rails with increased wear resistance for the construction of high-speed networks.

  14. 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.

  15. 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.

  16. The VK-8L High - Speed Camera

    NASA Astrophysics Data System (ADS)

    Venatovsky, I. V.; Tsukanov, A. A.; Kirillov, V. A.

    1985-02-01

    To enhance the time resolution of high-speed cine equipment during the investigation of rapidly flowing processes, a light source to illumi late an object under test is represented b7 solid-state laser exposure devices operating in the mode of Q-factor flodulation. With a high-speed eine cafiera being run in the continuous scanning mode, these devices will permit a sequence of fra Mlles to be obtained within a short exposure time of 150 ns to 200 nanoseconds. At scanning speeds of up to 250 m/s this will ensure satisfactory image quality from the slear viewpoint. In the case of faster continuous scanuin speeds and of shorter exposure times, it becomes necessary to run the high-speed cauera in the fl ode of frame-by-frame cinematography.

  17. ERROR CORRECTION IN HIGH SPEED ARITHMETIC,

    DTIC Science & Technology

    The errors due to a faulty high speed multiplier are shown to be iterative in nature. These errors are analyzed in various aspects. The arithmetic coding technique is suggested for the improvement of high speed multiplier reliability. Through a number theoretic investigation, a large class of arithmetic codes for single iterative error correction are developed. The codes are shown to have near-optimal rates and to render a simple decoding method. The implementation of these codes seems highly practical. (Author)

  18. Lubrication and cooling for high speed gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.

    1985-01-01

    The problems and failures occurring with the operation of high speed gears are discussed. The gearing losses associated with high speed gearing such as tooth mesh friction, bearing friction, churning, and windage are discussed with various ways shown to help reduce these losses and thereby improve efficiency. Several different methods of oil jet lubrication for high speed gearing are given such as into mesh, out of mesh, and radial jet lubrication. The experiments and analytical results for the various methods of oil jet lubrication are shown with the strengths and weaknesses of each method discussed. The analytical and experimental results of gear lubrication and cooling at various test conditions are presented. These results show the very definite need of improved methods of gear cooling at high speed and high load conditions.

  19. Speed control with end cushion for high speed air cylinder

    DOEpatents

    Stevens, Wayne W.; Solbrig, Charles W.

    1991-01-01

    A high speed air cylinder in which the longitudinal movement of the piston within the air cylinder tube is controlled by pressurizing the air cylinder tube on the accelerating side of the piston and releasing pressure at a controlled rate on the decelerating side of the piston. The invention also includes a method for determining the pressure required on both the accelerating and decelerating sides of the piston to move the piston with a given load through a predetermined distance at the desired velocity, bringing the piston to rest safely without piston bounce at the end of its complete stroke.

  20. A high-current rail-type gas switch with preionization by an additional corona discharge

    NASA Astrophysics Data System (ADS)

    Antipov, E. I.; Belozerov, O. S.; Krastelev, E. G.

    2016-12-01

    The characteristics of a high-current rail-type gas switch with preionization of the gas (air) in a spark gap by an additional corona discharge are investigated. The experiments were performed in a voltage range of 10-45 kV using a two-electrode switch consisting of two cylindrical electrodes with a diameter of 22 mm and a length of 100 mm and a set of laterally located corona-discharge needles. The requirements for the position and size of the needles are defined for which a corona discharge is ignited before a breakdown of the main gap and does not change to a sparking form, and the entire length of the rail electrodes is efficiently used. The fulfillment of these requirements ensures stable operation of the switch with a small variation of the pulse breakdown voltage, which is not more than 1% for a fixed voltage-pulse rise time in the range from 150 ns to 3.5 μs. A short delay time of the switch breakdown makes it possible to control the two-electrode switch by an overvoltage pulse of nanosecond duration.

  1. A high-current rail-type gas switch with preionization by an additional corona discharge

    SciTech Connect

    Antipov, E. I.; Belozerov, O. S.; Krastelev, E. G.

    2016-12-15

    The characteristics of a high-current rail-type gas switch with preionization of the gas (air) in a spark gap by an additional corona discharge are investigated. The experiments were performed in a voltage range of 10–45 kV using a two-electrode switch consisting of two cylindrical electrodes with a diameter of 22 mm and a length of 100 mm and a set of laterally located corona-discharge needles. The requirements for the position and size of the needles are defined for which a corona discharge is ignited before a breakdown of the main gap and does not change to a sparking form, and the entire length of the rail electrodes is efficiently used. The fulfillment of these requirements ensures stable operation of the switch with a small variation of the pulse breakdown voltage, which is not more than 1% for a fixed voltage-pulse rise time in the range from 150 ns to 3.5 μs. A short delay time of the switch breakdown makes it possible to control the two-electrode switch by an overvoltage pulse of nanosecond duration.

  2. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  3. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  4. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  5. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  6. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  7. Visualization of high speed liquid jet impaction on a moving surface.

    PubMed

    Guo, Yuchen; Green, Sheldon

    2015-04-17

    Two apparatuses for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device (for examining surface speeds between 0 and 25 m/sec) and a spinning disk device (for examining surface speeds between 15 and 100 m/sec). The air cannon linear traverse is a pneumatic energy-powered system that is designed to accelerate a metal rail surface mounted on top of a wooden projectile. A pressurized cylinder fitted with a solenoid valve rapidly releases pressurized air into the barrel, forcing the projectile down the cannon barrel. The projectile travels beneath a spray nozzle, which impinges a liquid jet onto its metal upper surface, and the projectile then hits a stopping mechanism. A camera records the jet impingement, and a pressure transducer records the spray nozzle backpressure. The spinning disk set-up consists of a steel disk that reaches speeds of 500 to 3,000 rpm via a variable frequency drive (VFD) motor. A spray system similar to that of the air cannon generates a liquid jet that impinges onto the spinning disc, and cameras placed at several optical access points record the jet impingement. Video recordings of jet impingement processes are recorded and examined to determine whether the outcome of impingement is splash, splatter, or deposition. The apparatuses are the first that involve the high speed impingement of low-Reynolds-number liquid jets on high speed moving surfaces. In addition to its rail industry applications, the described technique may be used for technical and industrial purposes such as steelmaking and may be relevant to high-speed 3D printing.

  8. Agile Electromagnetics Exploiting High Speed Logic (AEEHSL).

    DTIC Science & Technology

    2014-09-26

    examination and alteration of codes and filter weights 3. READ Mode - This mode enables the reading or replaying of the data from the digital tape recorder...available in this subsystems are used to initialize the * radar, clock the code from the high-speed code storage memory to drive the code modulator, delay...correlation process. There is storage space within the high speed memory for 32 codes of length 64 bits or less. The radiated code can be changed by a

  9. High-speed mirror-scanning tracker

    NASA Astrophysics Data System (ADS)

    Tong, HengWei

    1999-06-01

    This paper introduces a high speed single-mirror scanner developed by us as a versatile tracker. It can be connected with a high speed camera, a TV tracker (or color video recorder) /measurer/recorder. It can be guided by a computer, a joystick (automatic or manual) or TV tracker. In this paper, we also present the advantages of our scanner contrasted with the limitations of fixed camera system. In addition, several usable projects of mirror scanner are discussed.

  10. Study on the operational safety of high-speed trains exposed to stochastic winds

    NASA Astrophysics Data System (ADS)

    Yu, Meng-Ge; Zhang, Ji-Ye; Zhang, Ke-Yue; Zhang, Wei-Hua

    2014-06-01

    The characteristic wind curve (CWC) was commonly used in the previous work to evaluate the operational safety of the high-speed trains exposed to crosswinds. However, the CWC only provide the dividing line between safety state and failure state of high-speed trains, which can not evaluate the risk of derailment of high-speed trains when exposed to natural winds. In the present paper, a more realistic approach taking into account the stochastic characteristics of natural winds is proposed, which can give a reasonable and effective assessment of the operational safety of high-speed trains under stochastic winds. In this approach, the longitudinal and lateral components of stochastic winds are simulated based on the Cooper theory and harmonic superposition. An algorithm is set up for calculating the unsteady aerodynamic forces (moments) of the high-speed trains exposed to stochastic winds. A multi-body dynamic model of the rail vehicle is established to compute the vehicle system dynamic response subjected to the unsteady aerodynamic forces (moments) input. Then the statistical method is used to get the mean characteristic wind curve (MCWC) and spread range of the high-speed trains exposed to stochastic winds. It is found that the CWC provided by the previous analytical method produces over-conservative limits. The methodology proposed in the present paper can provide more significant reference for the safety operation of high-speed trains exposed to stochastic winds.

  11. A High Vacuum High Speed Ion Pump

    DOE R&D Accomplishments Database

    Foster, J. S. Jr.; Lawrence, E. O.; Lofgren, E. J.

    1952-08-27

    A vacuum pump based on the properties of a magnetically collimated electric discharge is described. It has a speed in the range 3000 to 7000 liters a second and a base pressure in the order of 10{sup -6} mm. (auth)

  12. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - A Hennessey Venom GT stands on the 3.5-mile long runway between test runs at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles. Photo credit: NASA/Kim Shiflett

  13. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - An engineer readies a Hennessey Venom GT for test runs on the 3.5-mile long runway at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles. Photo credit: NASA/Kim Shiflett

  14. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - Mechanics and engineers ready a Hennessey Venom GT for test runs on the 3.5-mile long runway at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles. Photo credit: NASA/Kim Shiflett

  15. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - Mechanics, engineers and Driver Brian Smith, in jumpsuit, ready a Hennessey Venom GT for test runs on the 3.5-mile long runway at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles. Photo credit: NASA/Kim Shiflett

  16. High Speed Prototype Car Test

    NASA Image and Video Library

    2014-01-10

    CAPE CANAVERAL, Fla. - The Performance Power Racing and Hennessey Performance teams pose with a Hennessey Venom GT at the 3.5-mile long runway at the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida. The teams are, from left, Hennessey's John Heinricy, John Hennessey, Brian Smith, Performance Power Racing's Johnny Bohmer, Matt Lundy and Jeff McEachran. The flat concrete runway is one of the few places in the world where high performance automobiles can be tested for aerodynamic and safety designs. Hennessey Performance of Sealy, Texas, worked with Performance Power Racing in West Palm Beach to arrange use of the NASA facility. Performance Power Racing has conducted numerous engineering tests on the runway with a variety of vehicles.

  17. Analysis of vibration and frequency transmission of high speed EMU with flexible model

    NASA Astrophysics Data System (ADS)

    Ren, Zun-Song; Yang, Guang; Wang, Shan-Shan; Sun, Shou-Guang

    2014-12-01

    When the operation speed of the high-speed train increases and the weight of the carbody becomes lighter, not only does the sensitivity of the wheel/rail contact get higher, but also the vibration frequency range of the vehicle system gets enlarged and more frequencies are transmitted from the wheelset to the carbody. It is important to investigate the vibration characteristics and the dynamic frequency transmission from the wheel/rail interface to the carbody of the high-speed electric multi-uint (EMU). An elastic highspeed vehicle dynamics model is established in which the carbody, bogieframes, and wheelsets are all dealt with as flexible body. A rigid high-speed vehicle dynamics model is set up to compare with the simulation results of the elastic model. In the rigid vehicle model, the carbody, bogieframes and wheelsets are treated as rigid component while the suspension and structure parameters are the same as used in the elastic model. The dynamic characteristic of the elastic high speed vehicle is investigated in time and frequency domains and the difference of the acceleration, frequency distribution and transmission of the two types of models are presented. The results show that the spectrumpower density of the vehicle decreases from the wheelset to the carbody and the acceleration transmission ratio is approximately from 1% to 10% for each suspension system. The frequency of the wheelset rotation is evident in the vibration of the flexible model and is transmitted from the wheelset to the bogieframe and to the carbody. The results of the flexible model are more reasonable than that of the rigid model. A field test data of the high speed train are presented to verify the simulation results. It shows that the simulation results are coincidentwith the field test data.

  18. Application of FBG sensing technique for monitoring and early warning system of high-speed railway track conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Yongjia; Liu, Fang; Jing, Yuhai; Li, Weilai

    2017-04-01

    High-speed railway has achieved remarkable development in China, and safety monitoring of high-speed railway is becoming an important research. Fiber bragg grating (FBG) sensing technology is applied for monitoring and early warning system of high-speed railway track condition in this paper. The sensor network is built by putting FBG sensors on the high-speed rail tracks, which is necessary for real-time online monitoring of railway track temperature, displacement and strain. These different variables are collected, processed and analyzed by FBG demodulator. In addition, the railway track temperature prediction model are established based on relevance vector regression algorithm, which further improves the prediction accuracy and generalization performance. The system has been applied in the realtime online monitoring and early warning system of Guangzhou-Shenzhen-Hong Kong high-speed railway track condition. The system is running in good condition and playing an important role in early warning.

  19. Machine Vision Techniques For High Speed Videography

    NASA Astrophysics Data System (ADS)

    Hunter, David B.

    1984-11-01

    The priority associated with U.S. efforts to increase productivity has led to, among other things, the development of Machine Vision systems for use in manufacturing automation requirements. Many such systems combine solid state television cameras and data processing equipment to facilitate high speed, on-line inspection and real time dimensional measurement of parts and assemblies. These parts are often randomly oriented and spaced on a conveyor belt under continuous motion. Television imagery of high speed events has historically been achieved by use of pulsed (strobe) illumination or high speed shutter techniques synchronized with a camera's vertical blanking to separate write and read cycle operation. Lack of synchronization between part position and camera scanning in most on-line applications precludes use of this vertical interval illumination technique. Alternatively, many Machine Vision cameras incorporate special techniques for asynchronous, stop-motion imaging. Such cameras are capable of imaging parts asynchronously at rates approaching 60 hertz while remaining compatible with standard video recording units. Techniques for asynchronous, stop-motion imaging have not been incorporated in cameras used for High Speed Videography. Imaging of these events has alternatively been obtained through the utilization of special, high frame rate cameras to minimize motion during the frame interval. High frame rate cameras must undoubtedly be utilized for recording of high speed events occurring at high repetition rates. However, such cameras require very specialized, and often expensive, video recording equipment. It seems, therefore, that Machine Vision cameras with capability for asynchronous, stop-motion imaging represent a viable approach for cost effective video recording of high speed events occurring at repetition rates up to 60 hertz.

  20. High speed flight effects on noise propagation

    NASA Astrophysics Data System (ADS)

    Burrin, R. H.; Ahuja, K. K.; Salikuddin, M.

    1987-01-01

    An experimental study to investigate the effects of source motion on sound propagation at high Mach numbers was devised to determine, in particular, if the large amplifications in the forward arc to high speeds, predicted by the 'convective amplification' factors normally used for low speeds, are realistic. An acoustic point source and a microphone, both immersed in flows up to a Mach number of 0.8, were used to obtain the convective amplification factors for comparison with predictions. The results confirmed the existence of high levels of noise propagating ahead of an aircraft flying at high speed. The commonly adopted prediction formula, namely (1 - M sub 0 cos theta sub E) exp -4, was categorically confirmed by the data for frequencies up to 5 kHz and Mach numbers of 0.2 to 0.8. At higher frequencies, the predictions are followed up to emission angles of 120 deg, but then deviate downward towards the direction of flight.

  1. Scientific Visualization in High Speed Network Environments

    NASA Technical Reports Server (NTRS)

    Vaziri, Arsi; Kutler, Paul (Technical Monitor)

    1997-01-01

    In several cases, new visualization techniques have vastly increased the researcher's ability to analyze and comprehend data. Similarly, the role of networks in providing an efficient supercomputing environment have become more critical and continue to grow at a faster rate than the increase in the processing capabilities of supercomputers. A close relationship between scientific visualization and high-speed networks in providing an important link to support efficient supercomputing is identified. The two technologies are driven by the increasing complexities and volume of supercomputer data. The interaction of scientific visualization and high-speed networks in a Computational Fluid Dynamics simulation/visualization environment are given. Current capabilities supported by high speed networks, supercomputers, and high-performance graphics workstations at the Numerical Aerodynamic Simulation Facility (NAS) at NASA Ames Research Center are described. Applied research in providing a supercomputer visualization environment to support future computational requirements are summarized.

  2. High speed hydrogen/graphite interaction

    NASA Technical Reports Server (NTRS)

    Kelly, A. J.; Hamman, R.; Sharma, O. P.; Harrje, D. T.

    1974-01-01

    Various aspects of a research program on high speed hydrogen/graphite interaction are presented. Major areas discussed are: (1) theoretical predictions of hydrogen/graphite erosion rates; (2) high temperature, nonequilibrium hydrogen flow in a nozzle; and (3) molecular beam studies of hydrogen/graphite erosion.

  3. High Speed Digital Camera Technology Review

    NASA Technical Reports Server (NTRS)

    Clements, Sandra D.

    2009-01-01

    A High Speed Digital Camera Technology Review (HSD Review) is being conducted to evaluate the state-of-the-shelf in this rapidly progressing industry. Five HSD cameras supplied by four camera manufacturers participated in a Field Test during the Space Shuttle Discovery STS-128 launch. Each camera was also subjected to Bench Tests in the ASRC Imaging Development Laboratory. Evaluation of the data from the Field and Bench Tests is underway. Representatives from the imaging communities at NASA / KSC and the Optical Systems Group are participating as reviewers. A High Speed Digital Video Camera Draft Specification was updated to address Shuttle engineering imagery requirements based on findings from this HSD Review. This draft specification will serve as the template for a High Speed Digital Video Camera Specification to be developed for the wider OSG imaging community under OSG Task OS-33.

  4. U. S. developers join magnetic rail push

    SciTech Connect

    O'Connor, L.

    1993-08-01

    This article examines the state of development of maglev trains in the USA. The topics of the article include an overview of the various European and Japanese types, an all American concept, and overcoming competition. The article includes a sidebar on at test run of the Intercityexpress, a high-speed wheel-on-rail train along the northeast of the USA scheduled for fall of 1993.

  5. DAC 22 High Speed Civil Transport Model

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Between tests, NASA research engineer Dave Hahne inspects a tenth-scale model of a supersonic transport model in the 30- by 60-Foot Tunnel at NASA Langley Research Center, Hampton, Virginia. The model is being used in support of NASA's High-Speed Research (HSR) program. Langley researchers are applying advance aerodynamic design methods to develop a wing leading-edge flap system which significantly improves low-speed fuel efficiency and reduces noise generated during takeoff operation. Langley is NASA's lead center for the agency's HSR program, aimed at developing technology to help U.S. industry compete in the rapidly expanding trans-oceanic transport market. A U.S. high-speed civil transport is expected to fly in about the year 2010. As envisioned, it would fly 300 passengers across the Pacific in about four hours at Mach 2.4 (approximately 1,600 mph/1950 kph) for a modest increase over business class fares.

  6. High Speed and Slow Motion: The Technology of Modern High Speed Cameras

    ERIC Educational Resources Information Center

    Vollmer, Michael; Mollmann, Klaus-Peter

    2011-01-01

    The enormous progress in the fields of microsystem technology, microelectronics and computer science has led to the development of powerful high speed cameras. Recently a number of such cameras became available as low cost consumer products which can also be used for the teaching of physics. The technology of high speed cameras is discussed,…

  7. High Speed and Slow Motion: The Technology of Modern High Speed Cameras

    ERIC Educational Resources Information Center

    Vollmer, Michael; Mollmann, Klaus-Peter

    2011-01-01

    The enormous progress in the fields of microsystem technology, microelectronics and computer science has led to the development of powerful high speed cameras. Recently a number of such cameras became available as low cost consumer products which can also be used for the teaching of physics. The technology of high speed cameras is discussed,…

  8. High speed technology development and evaluation

    NASA Astrophysics Data System (ADS)

    Parker, D. R.; Brown, E. R.; Dickson, J. F.

    1986-10-01

    Semiconductor technology suited to high on-board data handling rates was investigated. Very high speed discrete logic and high speed gate arrays; single chip digital signal processors and single chip floating point processing peripherals; and analog CCD technologies and custom designed CCD chips for synthetic aperture radar applications were assessed. The 2 micron CMOS technology is highly reliable, supporting semicustom design techniques. Process JGC, the CCD technology, is highly reliable except for tolerance to ionizing radiation. Reliability of the ECL 16-bit serial-parallel parallel-serial converter junction isolated bipolar process, process WZA, is compromised by a design error and oxide contamination contributing to high leakage levels. The bipolar circuit is tolerant to an ionizing radiation of 20kRad. Step stress environmental testing to 200 C produces no failures in CMOS and CCD technologies, but accelerates the degradation of the oxide contaminated bipolar process. All technologies are susceptible to single event upsets.

  9. Analysis of rail welding methods for mine rail access with the use of modern technologies

    NASA Astrophysics Data System (ADS)

    Usoltsev, A. A.; Shevchenko, R. A.; Kozyrev, N. A.; Kriukov, R. E.; Shishkin, P. E.

    2017-09-01

    Welded joint zones are weak sections of the railway track for all traffic cases (in the case of high-speed traffic and heavy traffic). In the paper advantages and disadvantages of the basic ways of rails welding, which are widely used today, are considered: electrocontact and aluminothermic. Carefully selected mode of differentially thermally strengthened rails string will allow the process of correction after heat treatment to be minimized and internal residual compressive stresses to be kept. Particular attention should be paid to the method of rails welding, in which after rails welding during their cooling it is offered to perform quasi-isothermal exposure in the temperature range of fine structure formation by passing pulses of alternating electric current through the welded joint maintaining this temperature until the end of the transformation. The use of quasi-isothermal exposure at a temperature of 600 – 650 °C makes it possible to obtain a finely dispersed structure of the welded seam of rails without additional heat treatment.

  10. Driver injury severity related to inclement weather at highway-rail grade crossings in the United States.

    PubMed

    Hao, Wei; Daniel, Janice

    2016-01-01

    Previous studies on crash modeling at highway-rail grade crossings were aimed at exploring the factors that are likely to increase the crash frequencies at highway-rail grade crossings. In recent years, modeling driver's injury severity at highway-rail grade crossings has received interest. Because there were substantial differences among different weather conditions for driver's injury severity, this study attempts to explore the impact of weather influence on driver injury at highway-rail grade crossing. Utilizing the most recent 10 years (2002-2011) of highway-rail grade crossing accident data, this study applied a mixed logit model to explore the determinants of driver injury severity under different weather conditions at highway-rail grade crossing. Analysis results indicate that drivers' injury severity at highway-rail grade crossings is strongly different for different weather conditions. It was found that the factors significantly impacting driver injury severity at highway-rail grade crossings include motor vehicle speed, train speed, driver's age, gender, area type, lighting condition, highway pavement, traffic volume, and time of day. The findings of this study indicate that crashes are more prevalent if vehicle drivers are driving at high speed or the oncoming trains are high speed. Hence, a reduction in speed limit during inclement weather conditions could be particularly effective in moderating injury severity, allowing more reaction time for last-minute maneuvering and braking in moments before impacts. In addition, inclement weather-related crashes were more likely to occur in open areas and highway-rail grade crossings without pavement and lighting. Paved highway-rail grade crossings with installation of lights could be particularly effective in moderating injury severity.

  11. High speed optical tomography for flow visualization

    NASA Technical Reports Server (NTRS)

    Snyder, Ray; Hesselink, Lambertus

    1987-01-01

    A novel optical architecture (based on holographic optical elements) for making high speed tomographic measurements is presented. The system is designed for making density or species concentration measurements in a nonsteady fluid or combustion flow. Performance evaluations of the optical system are discussed, and a test phase object was successfully reconstructed using this optical arrangement.

  12. Maneuverability Estimation of High-Speed Craft

    DTIC Science & Technology

    2015-06-01

    derived based on equations by Lewandowski and Denny- Hubble in order to find the fundamental maneuvering characteristics. The model is developed in...characteristic of high- speed craft. A mathematical model is derived based on equations by Lewandowski and Denny- Hubble in order to find the fundamental...33 C. EQUATIONS BY DENNY AND HUBBLE ................................................43 D. NOMOTO

  13. High-Speed Sealift Technology. Volume 1

    DTIC Science & Technology

    1998-09-01

    Engineering Directorate Technology Projection Report HIGH-SPEED SEALIFT TECHNOLOGY Volume 1 BY OWEN K. RITTER MICHAEL T. TEMPLEMAN...7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Surface Warfare Center,Carderock Division,Total Ship Systems Engineering Directorate...11 3.4.3.2 Diesel Engines

  14. Laser Trigger For High Speed Camera

    NASA Astrophysics Data System (ADS)

    Chang, Rong-Seng; Lin, Chin-Wu; Cheng, Tung

    1987-09-01

    High speed camera coorperated with laser trigger to catch high speed unpredictable events has many applications: such as scoring system for the end game of missile interception, war head explosive study etc. When the event happening in a very short duration, the repetition rate of the laser ranging must be as high as 5K herze and the pulse duration should be less than 10 nsec. In some environment, like inside the aircraft, the abailable space for high speed camera to set up is limited, large film capacity camera could not be used. In order to use the small capacity film, the exact trigger time for the camera are especially important. The target velocity, camera acceleration characteristics, speed regulation, camera size, weight and the ruggedness are all be considered before the laser trigger be designed. Electric temporal gate is used to measure the time of flight ranging datum. The triangular distance measurement principle are also used to get the ranging when the base line i.e. the distance between the laser transmitter and receiver are large enough.

  15. Italian High-speed Airplane Engines

    NASA Technical Reports Server (NTRS)

    Bona, C F

    1940-01-01

    This paper presents an account of Italian high-speed engine designs. The tests were performed on the Fiat AS6 engine, and all components of that engine are discussed from cylinders to superchargers as well as the test set-up. The results of the bench tests are given along with the performance of the engines in various races.

  16. Impedance Matching for High Speed Optical Communication

    DTIC Science & Technology

    1988-06-01

    OPTICAL COMMUNICATION 16, PERaPNAL AUATHOR(S)ur. Kenry Zmuda IfTYJE OF REPORT 13b TIMý COVA5ED 14. DATE OF REPORT (Year, Month. Day) I5 PAGE COUNT EnaJ...294. 5. D. J. Nicholson and H. Zmuda, "Matching Structures for High Speed Optical Communication ", To be published in the Proceedings of Society of

  17. High-speed data word monitor

    NASA Technical Reports Server (NTRS)

    Wirth, M. N.

    1975-01-01

    Small, portable, self-contained device provides high-speed display of bit pattern or any selected portion of transmission, can suppress filler patterns so that display is not updated, and can freeze display so that specific event may be observed in detail.

  18. High-Speed Photometry of Catalina Sources

    NASA Astrophysics Data System (ADS)

    Warner, Brian; Woudt, Patrick A.

    2010-12-01

    High-speed photometry of cataclysmic variables selected from the Catalina Real-Time Transient (CRTS) survey results in orbital periods for 12 objects (10 dwarf novae and 2 polars). The period distribution for all CRTS sources has a pronounced peak near 80 minutes, confirming previous results from the Sloan Digital Sky Survey cataclysmic variables.

  19. High-Speed Schlieren Movies of Decelerators at Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    1960-01-01

    Tests were conducted on several types of porous parachutes, a paraglider, and a simulated retrorocket. Mach numbers ranged from 1.8-3.0, porosity from 20-80 percent, and camera speeds from 1680-3000 feet per second (fps) in trials with porous parachutes. Trials of reefed parachutes were conducted at Mach number 2.0 and reefing of 12-33 percent at camera speeds of 600 fps. A flexible parachute with an inflatable ring in the periphery of the canopy was tested at Reynolds number 750,000 per foot, Mach number 2.85, porosity of 28 percent, and camera speed of 36oo fps. A vortex-ring parachute was tested at Mach number 2.2 and camera speed of 3000 fps. The paraglider, with a sweepback of 45 degrees at an angle of attack of 45 degrees was tested at Mach number 2.65, drag coefficient of 0.200, and lift coefficient of 0.278 at a camera speed of 600 fps. A cold air jet exhausting upstream from the center of a bluff body was used to simulate a retrorocket. The free-stream Mach number was 2.0, free-stream dynamic pressure was 620 lb/sq ft, jet-exit static pressure ratio was 10.9, and camera speed was 600 fps.

  20. High-Speed Schlieren Movies of Decelerators at Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    1960-01-01

    Tests were conducted on several types of porous parachutes, a paraglider, and a simulated retrorocket. Mach numbers ranged from 1.8-3.0, porosity from 20-80 percent, and camera speeds from 1680-3000 feet per second (fps) in trials with porous parachutes. Trials of reefed parachutes were conducted at Mach number 2.0 and reefing of 12-33 percent at camera speeds of 600 fps. A flexible parachute with an inflatable ring in the periphery of the canopy was tested at Reynolds number 750,000 per foot, Mach number 2.85, porosity of 28 percent, and camera speed of 36oo fps. A vortex-ring parachute was tested at Mach number 2.2 and camera speed of 3000 fps. The paraglider, with a sweepback of 45 degrees at an angle of attack of 45 degrees was tested at Mach number 2.65, drag coefficient of 0.200, and lift coefficient of 0.278 at a camera speed of 600 fps. A cold air jet exhausting upstream from the center of a bluff body was used to simulate a retrorocket. The free-stream Mach number was 2.0, free-stream dynamic pressure was 620 lb/sq ft, jet-exit static pressure ratio was 10.9, and camera speed was 600 fps.

  1. Pulsed laser triggered high speed microfluidic switch

    NASA Astrophysics Data System (ADS)

    Wu, Ting-Hsiang; Gao, Lanyu; Chen, Yue; Wei, Kenneth; Chiou, Pei-Yu

    2008-10-01

    We report a high-speed microfluidic switch capable of achieving a switching time of 10 μs. The switching mechanism is realized by exciting dynamic vapor bubbles with focused laser pulses in a microfluidic polydimethylsiloxane (PDMS) channel. The bubble expansion deforms the elastic PDMS channel wall and squeezes the adjacent sample channel to control its fluid and particle flows as captured by the time-resolved imaging system. A switching of polystyrene microspheres in a Y-shaped channel has also been demonstrated. This ultrafast laser triggered switching mechanism has the potential to advance the sorting speed of state-of-the-art microscale fluorescence activated cell sorting devices.

  2. Some problems of high speed travel

    PubMed Central

    Reader, D. C.

    1975-01-01

    Some aspects of high speed flight are examined to investigate whether increase in speed implies any lowering of safety standards. The problem of circadian dysrhythmia is discussed and methods of attenuating its effects are explained and some new hypnotic drugs are mentioned. The risk of decompression has been quantified and predictions have been made for risks in commercial service. Cosmic radiation in supersonic aircraft is unlikely to limit commercial operation or significantly increase risks to passengers and crew. The supersonic boom is likely to limit the terrain over which supersonic aircraft can operate and regulations covering engine noise on the ground could restrict some flights. PMID:1208294

  3. High Speed SPM of Functional Materials

    SciTech Connect

    Huey, Bryan D.

    2015-08-14

    The development and optimization of applications comprising functional materials necessitates a thorough understanding of their static and dynamic properties and performance at the nanoscale. Leveraging High Speed SPM and concepts enabled by it, efficient measurements and maps with nanoscale and nanosecond temporal resolution are uniquely feasible. This includes recent enhancements for topographic, conductivity, ferroelectric, and piezoelectric properties as originally proposed, as well as newly developed methods or improvements to AFM-based mechanical, friction, thermal, and photoconductivity measurements. The results of this work reveal fundamental mechanisms of operation, and suggest new approaches for improving the ultimate speed and/or efficiency, of data storage systems, magnetic-electric sensors, and solar cells.

  4. High-speed spectroradiometer for remote sensing.

    PubMed

    Miyazaki, T; Shimizu, H; Yasuoka, Y

    1987-11-15

    A high-speed spectroradiometer designed for spectral reflectance measurement in remote sensing is described. This instrument uses a monochromatic grating and a photomultiplier system for light detection and sweeps over the 400-850-nm wavelength spectral range with the spectral resolution of 2 nm within 1 s. The instrument has the inherent advantage of portability and speed of operation which make it particularly suitable for field work in the area of fast moving surfaces, e.g., water with wave motion. Some applications of its use in laboratory and field experiments also have been presented. The instrument would seem to be an appropriate instrument for ground data collection in remote sensing.

  5. Sensor study for high speed autonomous operations

    NASA Astrophysics Data System (ADS)

    Schneider, Anne; La Celle, Zachary; Lacaze, Alberto; Murphy, Karl; Del Giorno, Mark; Close, Ryan

    2015-06-01

    As robotic ground systems advance in capabilities and begin to fulfill new roles in both civilian and military life, the limitation of slow operational speed has become a hindrance to the wide-spread adoption of these systems. For example, military convoys are reluctant to employ autonomous vehicles when these systems slow their movement from 60 miles per hour down to 40. However, these autonomous systems must operate at these lower speeds due to the limitations of the sensors they employ. Robotic Research, with its extensive experience in ground autonomy and associated problems therein, in conjunction with CERDEC/Night Vision and Electronic Sensors Directorate (NVESD), has performed a study to specify system and detection requirements; determined how current autonomy sensors perform in various scenarios; and analyzed how sensors should be employed to increase operational speeds of ground vehicles. The sensors evaluated in this study include the state of the art in LADAR/LIDAR, Radar, Electro-Optical, and Infrared sensors, and have been analyzed at high speeds to study their effectiveness in detecting and accounting for obstacles and other perception challenges. By creating a common set of testing benchmarks, and by testing in a wide range of real-world conditions, Robotic Research has evaluated where sensors can be successfully employed today; where sensors fall short; and which technologies should be examined and developed further. This study is the first step to achieve the overarching goal of doubling ground vehicle speeds on any given terrain.

  6. Technology needs for high speed rotorcraft (2)

    NASA Technical Reports Server (NTRS)

    Scott, Mark W.

    1991-01-01

    An analytical study was conducted to identify rotorcraft concepts best capable of combining a cruise speed of 350 to 450 knots with helicopter-like low speed attributes, and to define the technology advancements needed to make them viable by the year 2000. A systematic approach was used to compare the relative attributes and mission gross weights for a wide range of concepts, resulting in a downselect to the most promising concept/mission pairs. For transport missions, tilt-wing and variable diameter tilt-rotor (VDTR) concepts were found to be superior. For a military scout/attack role, the VDTR was best, although a shrouded rotor concept could provide a highly agile, low observable alternative if its weight empty fraction could be reduced. A design speed of 375 to 425 knots was found to be the maximum desirable for transport missions, with higher speed producing rapidly diminishing benefits in productivity. The key technologies that require advancement to make the tilt-wing and VDTR concepts viable are in the areas of wing and proprotor aerodynamics, efficient structural design, flight controls, refinement of the geared flap pitch control system, expansion of the speed/descent envelope, and the structural and aerodynamic tradeoffs of wing thickness and forward sweep. For the shrouded rotor, weight reduction is essential, particularly with respect to the mechanism for covering the rotor in cruise.

  7. Design of high-speed turnouts and crossings

    NASA Astrophysics Data System (ADS)

    Raif, Lukáš; Puda, Bohuslav; Havlík, Jiří; Smolka, Marek

    2017-09-01

    Recently, the new ways to improve the railway switches and crossings have been sought, as the railway transport increases its operating speed. The expectation of these adjustments is to decrease the dynamic load, which usually increases together with velocity, and this influences the comfort of the vehicle passage, the wear of the structural parts and the cost of maintenance. These adjustments are primarily the turnout elements such as the optimized geometry of the turnout branch line by means of transition curves application, which minimizes the lateral acceleration during the vehicle passage through the track curve. The rail inclination is solved either by means of inclination in fastening system, or by machining of the rail head shape, because this ways of adjustment retain the wheel-rail interaction characteristics along the whole length of the turnout. Secondly, it is the crossing with movable part, which excludes the interruption of the running surface and optimization of the railway stiffness throughout the whole turnout length as well. We can see that the different stiffness along the turnout influences the dynamic load and it is necessary to optimize the discontinuities in the stiffness along the whole length of the turnout. For this purpose, the numeric modeling is carried out to seek the areas with the highest stiffness and subsequently, the system of stiffness optimization will be designed.

  8. High speed printing with polygon scan heads

    NASA Astrophysics Data System (ADS)

    Stutz, Glenn

    2016-03-01

    To reduce and in many cases eliminate the costs associated with high volume printing of consumer and industrial products, this paper investigates and validates the use of the new generation of high speed pulse on demand (POD) lasers in concert with high speed (HS) polygon scan heads (PSH). Associated costs include consumables such as printing ink and nozzles, provisioning labor, maintenance and repair expense as well as reduction of printing lines due to high through put. Targets that are applicable and investigated include direct printing on plastics, printing on paper/cardboard as well as printing on labels. Market segments would include consumer products (CPG), medical and pharmaceutical products, universal ID (UID), and industrial products. In regards to the POD lasers employed, the wavelengths include UV(355nm), Green (532nm) and IR (1064nm) operating within the repetition range of 180 to 250 KHz.

  9. Safety issues in high speed machining

    NASA Astrophysics Data System (ADS)

    1994-05-01

    There are several risks related to High-Speed Milling, but they have not been systematically determined or studied so far. Increased loads by high centrifugal forces may result in dramatic hazards. Flying tools or fragments from a tool with high kinetic energy may damage surrounding people, machines and devices. In the project, mechanical risks were evaluated, theoretic values for kinetic energies of rotating tools were calculated, possible damages of the flying objects were determined and terms to eliminate the risks were considered. The noise levels of the High-Speed Machining center owned by the Helsinki University of Technology (HUT) and the Technical Research Center of Finland (VTT) in practical machining situation were measured and the results were compared to those after basic preventive measures were taken.

  10. High speed, high current pulsed driver circuit

    DOEpatents

    Carlen, Christopher R.

    2017-03-21

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

  11. Data Capture Technique for High Speed Signaling

    DOEpatents

    Barrett, Wayne Melvin; Chen, Dong; Coteus, Paul William; Gara, Alan Gene; Jackson, Rory; Kopcsay, Gerard Vincent; Nathanson, Ben Jesse; Vranas, Paylos Michael; Takken, Todd E.

    2008-08-26

    A data capture technique for high speed signaling to allow for optimal sampling of an asynchronous data stream. This technique allows for extremely high data rates and does not require that a clock be sent with the data as is done in source synchronous systems. The present invention also provides a hardware mechanism for automatically adjusting transmission delays for optimal two-bit simultaneous bi-directional (SiBiDi) signaling.

  12. High Speed Blood and Fluid Transfusion Equipment

    DTIC Science & Technology

    2010-06-01

    it stores energy for heating fluid when not attached to an external power source, (2) that it provides for high heating and infusion rates, up to...8217 % High Speed Blood and Fluid Transfusion Equipment Final Report Prepared by: Rocky Research 1598 Foothill Drive Boulder City, NV 89005...University of Nevada School of Medicine Trauma Institute Department of Surgery 2040 W. Charleston Blvd #302 Las Vegas, NV 89102 Principal

  13. High-speed civil transport study

    NASA Technical Reports Server (NTRS)

    1989-01-01

    A system study of the potential for a high-speed commercial transport has addressed technological, economic, and environmental constraints. Market projections indicate a need for fleets of transports with supersonic or greater cruise speeds by the year 2000 to 2005. The associated design requirements called for a vehicle to carry 250 to 300 passengers over a range of 5,000 to 6,000 nautical miles. The study was initially unconstrained in terms of vehicle characteristic, such as cruise speed, propulsion systems, fuels, or structural materials. Analyses led to a focus on the most promising vehicle concepts. These were concepts that used a kerosene-type fuel and cruised at Mach numbers between 2.0 to 3.2. Further systems study identified the impact of environmental constraints (for community noise, sonic boom, and engine emissions) on economic attractiveness and technological needs. Results showed that current technology cannot produce a viable high-speed civil transport; significant advances are required to reduce takeoff gross weight and allow for both economic attractiveness and environmental accepatability. Specific technological requirements were identified to meet these needs.

  14. High-speed civil transport study. Summary

    NASA Technical Reports Server (NTRS)

    1989-01-01

    A system of study of the potential for a high speed commercial transport aircraft addressed technology, economic, and environmental constraints. Market projections indicated a need for fleets of transport with supersonic or greater cruise speeds by the years 2000 to 2005. The associated design requirements called for a vehicle to carry 250 to 300 passengers over a range of 5000 to 6000 nautical miles. The study was initially unconstrained in terms of vehicle characteristics, such as cruise speed, propulsion systems, fuels, or structural materials. Analyses led to a focus on the most promising vehicle concepts. These were concepts that used a kerosene type fuel and cruised at Mach numbers between 2.0 to 3.2. Further systems study identified the impact of environmental constraints (for community noise, sonic boom, and engine emissions) on economic attractiveness and technological needs. Results showed that current technology cannot produce a viable high speed civil transport. Significant advances are needed to take off gross weight and allow for both economic attractiveness and environment acceptability. Specific technological requirements were identified to meet these needs.

  15. Probe characterization of high-current driven metal plasma in a vacuum-arc rail gun

    NASA Astrophysics Data System (ADS)

    Vijayan, T.; Roychowdhury, P.; Venkatramani, N.

    2004-10-01

    The characteristics of metal plasma launched by high-current electric arc in a vacuum-arc rail gun are determined by employing electrical and magnetic probes. These measurements are validated by results from theoretical simulations. The arc coupled nonlinear circuit equations are solved simultaneously with the Newtonian arc motion and revealed the undercritically damped behavior of the arc current identical to the arc-current signal recorded by the Rogowski magnetic probe. Similarly the arc velocity and displacement derived from the signatures of B-dot probes are shown to concur closely with the results of J ×B propulsion from simulation. The heating of plasma is formulated in a three-electron population regime with direct arc energy coupling through magnetohydrodynamic, ion-acoustic, Coulomb, and neutral interactions. This results in high temperature (Te) of hundreds of eV in the arc as revealed by the simulation. Hence Te of the rapidly cooling and equilibrating plasma that emerged from the muzzle is high around 80-90eV, which is confirmed by Langmuir electric probe measurements. Density ne of this metal plasma is shown to be in the range 4×1021-6×1021m-3 and includes multiple ion charge states. The exit velocity of the plasma measured by a pair of Langmuir probes is close to 2.2×106cm/s and matched well with the arc velocity determined by the B-dot probes and the results from simulation.

  16. High Speed Research Program Sonic Fatigue

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A. (Technical Monitor); Beier, Theodor H.; Heaton, Paul

    2005-01-01

    The objective of this sonic fatigue summary is to provide major findings and technical results of studies, initiated in 1994, to assess sonic fatigue behavior of structure that is being considered for the High Speed Civil Transport (HSCT). High Speed Research (HSR) program objectives in the area of sonic fatigue were to predict inlet, exhaust and boundary layer acoustic loads; measure high cycle fatigue data for materials developed during the HSR program; develop advanced sonic fatigue calculation methods to reduce required conservatism in airframe designs; develop damping techniques for sonic fatigue reduction where weight effective; develop wing and fuselage sonic fatigue design requirements; and perform sonic fatigue analyses on HSCT structural concepts to provide guidance to design teams. All goals were partially achieved, but none were completed due to the premature conclusion of the HSR program. A summary of major program findings and recommendations for continued effort are included in the report.

  17. Development of a Revolutionary High Speed Spindle

    NASA Technical Reports Server (NTRS)

    Agba, Emmanuel I.

    1999-01-01

    This report presents the development of a hydraulic motor driven spindle system to be employed for high speed machining of composite materials and metals. The spindle system is conceived to be easily retrofitted into conventional milling machines. The need for the hydraulic spindle arises because of the limitations placed on conventional electric motor driven spindles by the low cutting power and the presence of vibrational phenomena associated with voltage frequency at high rotational speeds. Also, the electric motors are usually large and expensive when power requirements are moderately high. In contrast, hydraulic motor driven spindles promise a distinct increase in spindle life over the conventional electric motor driven spindles. In this report, existing technologies applicable to spindle holder for severe operating conditions were reviewed, conceptual designs of spindle holder system were developed and evaluated, and a detailed design of an acceptable concept was conducted. Finally, a rapid prototype of the design was produced for design evaluation.

  18. Architectures and applications of high-speed vision

    NASA Astrophysics Data System (ADS)

    Watanabe, Yoshihiro; Oku, Hiromasa; Ishikawa, Masatoshi

    2014-11-01

    With the progress made in high-speed imaging technology, image processing systems that can process images at high frame rates, as well as their applications, are expected. In this article, we examine architectures for high-speed vision systems, and also dynamic image control, which can realize high-speed active optical systems. In addition, we also give an overview of some applications in which high-speed vision is used, including man-machine interfaces, image sensing, interactive displays, high-speed three-dimensional sensing, high-speed digital archiving, microvisual feedback, and high-speed intelligent robots.

  19. Effects of anchoring and arc structure on the control authority of a rail plasma actuator

    NASA Astrophysics Data System (ADS)

    Choi, Young-Joon; Gray, Miles; Sirohi, Jayant; Raja, Laxminarayan L.

    2017-09-01

    Experiments were conducted on a rail plasma actuator (RailPAc) with different electrode cross sections (rails or rods) to assess methods to improve the actuation authority, defined as the impulse generated for a given electrical input. The arc was characterized with electrical measurements and high-speed images, while impulse measurements quantified the actuation authority. A RailPAc power supply capable of delivering  ∼1 kA of current at  ∼100 V was connected to rod electrodes (free-floating with circular cross-section) and rail electrodes (flush-mounted in a flat plate with rectangular cross-section). High-speed images show that the rail electrodes cause the arc to anchor itself to the anode electrode and transit in discrete jumps, while rod electrodes permit the arc to transit smoothly without anchoring. The impulse measurements reveal that the anchoring reduces the actuation authority by  ∼21% compared to a smooth transit, and the effect of anchoring can be suppressed by reducing the gap between the rails to 2 mm. The study further demonstrates that if a smooth transit is achieved, the control authority can be increased with a larger gap and larger arc current. In conclusion, the actuation authority of a RailPAc can be maximized by carefully choosing a gap width that prevents anchoring. Further study is warranted to increase the RailPAc actuation authority by introducing multiple turns of wires beneath the RailPAc to augment the induced magnetic field.

  20. Propagation characteristics of ultrasonic guided waves in continuously welded rail

    NASA Astrophysics Data System (ADS)

    Yao, Wenqing; Sheng, Fuwei; Wei, Xiaoyuan; Zhang, Lei; Yang, Yuan

    2017-07-01

    Rail defects cause numerous railway accidents. Trains are derailed and serious consequences often occur. Compared to traditional bulk wave testing, ultrasonic guided waves (UGWs) can provide larger monitoring ranges and complete coverage of the waveguide cross-section. These advantages are of significant importance for the non-destructive testing (NDT) of the continuously welded rail, and the technique is therefore widely used in high-speed railways. UGWs in continuous welded rail (CWR) and their propagation characteristics have been discussed in this paper. Finite element methods (FEMs) were used to accomplish a vibration modal analysis, which is extended by a subsequent dispersion analysis. Wave structure features were illustrated by displacement profiles. It was concluded that guided waves have the ability to detect defects in the rail via choice of proper mode and frequency. Additionally, thermal conduction that is caused by temperature variation in the rail is added into modeling and simulation. The results indicated that unbalanced thermal distribution may lead to the attenuation of UGWs in the rail.

  1. CMOS Image Sensors for High Speed Applications.

    PubMed

    El-Desouki, Munir; Deen, M Jamal; Fang, Qiyin; Liu, Louis; Tse, Frances; Armstrong, David

    2009-01-01

    Recent advances in deep submicron CMOS technologies and improved pixel designs have enabled CMOS-based imagers to surpass charge-coupled devices (CCD) imaging technology for mainstream applications. The parallel outputs that CMOS imagers can offer, in addition to complete camera-on-a-chip solutions due to being fabricated in standard CMOS technologies, result in compelling advantages in speed and system throughput. Since there is a practical limit on the minimum pixel size (4∼5 μm) due to limitations in the optics, CMOS technology scaling can allow for an increased number of transistors to be integrated into the pixel to improve both detection and signal processing. Such smart pixels truly show the potential of CMOS technology for imaging applications allowing CMOS imagers to achieve the image quality and global shuttering performance necessary to meet the demands of ultrahigh-speed applications. In this paper, a review of CMOS-based high-speed imager design is presented and the various implementations that target ultrahigh-speed imaging are described. This work also discusses the design, layout and simulation results of an ultrahigh acquisition rate CMOS active-pixel sensor imager that can take 8 frames at a rate of more than a billion frames per second (fps).

  2. Abbreviated annealing of high-speed steel

    SciTech Connect

    Zablotskii, V.K.; Bartel, G.P.

    1987-07-01

    The authors investigate the structural and phase transformations during the heating, holding, and cooling of high-speed steels of two basic groups: tungsten (R18, R12, R12F3, and R12F4K5) and tungsten-molybdenum (R6M5, 10R6M5, R6M5K5, R8M3, 10R8M3, and R8M3K6S) steels in the forged state. They propose a cooling regime with complete alpha-gamma recrystallization whose implementation at a Soviet steel plant has made it possible to reduce the duration of heat treatment and increase productivity by 20% in cutting the annealed high-speed steels.

  3. High-speed massively parallel scanning

    DOEpatents

    Decker, Derek E.

    2010-07-06

    A new technique for recording a series of images of a high-speed event (such as, but not limited to: ballistics, explosives, laser induced changes in materials, etc.) is presented. Such technique(s) makes use of a lenslet array to take image picture elements (pixels) and concentrate light from each pixel into a spot that is much smaller than the pixel. This array of spots illuminates a detector region (e.g., film, as one embodiment) which is scanned transverse to the light, creating tracks of exposed regions. Each track is a time history of the light intensity for a single pixel. By appropriately configuring the array of concentrated spots with respect to the scanning direction of the detection material, different tracks fit between pixels and sufficient lengths are possible which can be of interest in several high-speed imaging applications.

  4. Pulse Detonation Engines for High Speed Flight

    NASA Technical Reports Server (NTRS)

    Povinelli, Louis A.

    2002-01-01

    Revolutionary concepts in propulsion are required in order to achieve high-speed cruise capability in the atmosphere and for low cost reliable systems for earth to orbit missions. One of the advanced concepts under study is the air-breathing pulse detonation engine. Additional work remains in order to establish the role and performance of a PDE in flight applications, either as a stand-alone device or as part of a combined cycle system. In this paper, we shall offer a few remarks on some of these remaining issues, i.e., combined cycle systems, nozzles and exhaust systems and thrust per unit frontal area limitations. Currently, an intensive experimental and numerical effort is underway in order to quantify the propulsion performance characteristics of this device. In this paper, we shall highlight our recent efforts to elucidate the propulsion potential of pulse detonation engines and their possible application to high-speed or hypersonic systems.

  5. High-speed tensile test instrument.

    PubMed

    Mott, P H; Twigg, J N; Roland, D F; Schrader, H S; Pathak, J A; Roland, C M

    2007-04-01

    A novel high-speed tensile test instrument is described, capable of measuring the mechanical response of elastomers at strain rates ranging from 10 to 1600 s(-1) for strains through failure. The device employs a drop weight that engages levers to stretch a sample on a horizontal track. To improve dynamic equilibrium, a common problem in high speed testing, equal and opposite loading was applied to each end of the sample. Demonstrative results are reported for two elastomers at strain rates to 588 s(-1) with maximum strains of 4.3. At the higher strain rates, there is a substantial inertial contribution to the measured force, an effect unaccounted for in prior works using the drop weight technique. The strain rates were essentially constant over most of the strain range and fill a three-decade gap in the data from existing methods.

  6. High speed receiver for capsule endoscope.

    PubMed

    Woo, S H; Yoon, K W; Moon, Y K; Lee, J H; Park, H J; Kim, T W; Choi, H C; Won, C H; Cho, J H

    2010-10-01

    In this study, a high-speed receiver for a capsule endoscope was proposed and implemented. The proposed receiver could receive 20 Mbps data that was sufficient to receive images with a higher resolution than conventional receivers. The receiver used a 1.2 GHz band to receive radio frequency (RF) signal, and demodulated the signal to an intermediate frequency (IF) stage (150 MHz). The demodulated signal was amplified, filtered, and under-sampled by a high-speed analog-to-digital converter (ADC). In order to decode the under-sampled data in real time, a simple frequency detection algorithm was selected and was implemented by using a FPGA. The implemented system could receive 20 Mbps data.

  7. Rail roughness and rolling noise in tramways

    NASA Astrophysics Data System (ADS)

    Chiacchiari, L.; Thompson, DJ; Squicciarini, G.; Ntotsios, E.; Loprencipe, G.

    2016-09-01

    Companies which manage railway networks have to cope continually with the problem of operating safety and maintenance intervention issues related to rail surface irregularities. A lot of experience has been gained in recent years in railway applications but the case of tramways is quite different; in this field there are no specific criteria to define any intervention on rail surface restoration. This paper shows measurements carried out on some stretches of a tram network with the CAT equipment (Corrugation Analysis Trolley) for the principal purpose of detecting different states of degradation of the rails and identifying a level of deterioration to be associated with the need for maintenance through rail grinding. The measured roughness is used as an input parameter into prediction models for both rolling noise and ground vibration to show the potential effect that high levels of roughness can have in urban environment. Rolling noise predictions are also compared with noise measurements to illustrate the applicability of the modelling approach. Particular attention is given to the way the contact filter needs to be modelled in the specific case of trams that generally operate at low speed. Finally an empirical approach to assess vibration levels in buildings is presented.

  8. The NASA high-speed turboprop program

    NASA Technical Reports Server (NTRS)

    Dugan, J. F.; Miller, B. A.; Graber, E. J.; Sagerser, D. A.

    1980-01-01

    Technology readiness for Mach 0.7 to 0.8 turboprop powered aircraft with the potential for fuel savings and DOC reductions of up to 30 and 15 percent respectively relative to current in-service aircraft is addressed. The areas of propeller aeroacoustics, propeller structures, turboprop installed performance, aircraft cabin environment, and turboprop engine and aircraft studies are emphasized. Large scale propeller characteristics and high speed propeller flight research tests using a modified testbed aircraft are also considered.

  9. The high-speed camera ULTRACAM

    NASA Astrophysics Data System (ADS)

    Marsh, T. R.; Dhillon, V. S.

    2006-08-01

    ULTRACAM is a high-speed, tri-band CCD camera designed for observations of time variable celestial objects. Commissioned on the 4.2m WHT in La Palma, it has now been used for observations of many types of phenomena and objects including stellar occultations, accreting black-holes, neutron stars and white dwarfs, pulsars, eclipsing binaries and pulsating stars. In this paper we describe the salient features of ULTRACAM and discuss some of the results of its use.

  10. High-speed Digital Color Imaging Pyrometry

    DTIC Science & Technology

    2011-08-01

    and environment of the events. To overcome these challenges, we have characterized and calibrated a digital high-speed color camera that may be...correction) to determine their effect on the calculated temperature. Using this technique with a Phantom color camera , we measured the temperature of...constant value of approximately 1980~K. 15. SUBJECT TERMS Pyrometry, color camera 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT

  11. Technology needs for high speed rotorcraft (3)

    NASA Technical Reports Server (NTRS)

    Detore, Jack; Conway, Scott

    1991-01-01

    The spectrum of vertical takeoff and landing (VTOL) type aircraft is examined to determine which aircraft are most likely to achieve high subsonic cruise speeds and have hover qualities similar to a helicopter. Two civil mission profiles are considered: a 600-n.mi. mission for a 15- and a 30-passenger payload. Applying current technology, only the 15- and 30-passenger tiltfold aircraft are capable of attaining the 450-knot design goal. The two tiltfold aircraft at 450 knots and a 30-passenger tiltrotor at 375 knots were further developed for the Task II technology analysis. A program called High-Speed Total Envelope Proprotor (HI-STEP) is recommended to meet several of these issues based on the tiltrotor concept. A program called Tiltfold System (TFS) is recommended based on the tiltrotor concept. A task is identified to resolve the best design speed from productivity and demand considerations based on the technology that emerges from the recommended programs. HI-STEP's goals are to investigate propulsive efficiency, maneuver loads, and aeroelastic stability. Programs currently in progress that may meet the other technology needs include the Integrated High Performance Turbine Engine Technology (IHPTET) (NASA Lewis) and the Advanced Structural Concepts Program funded through NASA Langley.

  12. MM-122: High speed civil transport

    NASA Technical Reports Server (NTRS)

    Demarest, Bill; Anders, Kurt; Manchec, John; Yang, Eric; Overgaard, Dan; Kalkwarf, Mike

    1992-01-01

    The rapidly expanding Pacific Rim market along with other growing markets indicates that the future market potential for a high speed civil transport is great indeed. The MM-122 is the answer to the international market desire for a state of the art, long range, high speed civil transport. It will carry 250 passengers a distance of 5200 nm at over twice the speed of sound. The MM-122 is designed to incorporate the latest technologies in the areas of control systems, propulsions, aerodynamics, and materials. The MM-122 will accomplish these goals using the following design parameters. First, a double delta wing planform with highly swept canards and an appropriately area ruled fuselage will be incorporated to accomplish desired aerodynamic characteristics. Propulsion will be provided by four low bypass variable cycle turbofan engines. A quad-redundant fly-by-wire flight control system will be incorporated to provide appropriate static stability and level 1 handling qualities. Finally, the latest in conventional metallic and modern composite materials will be used to provide desired weight and performance characteristics. The MM-122 incorporates the latest in technology and cost minimization techniques to provide a viable solution to this future market potential.

  13. 14 CFR 25.253 - High-speed characteristics.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false High-speed characteristics. 25.253 Section...-speed characteristics. (a) Speed increase and recovery characteristics. The following speed increase and... inadvertent speed increases (including upsets in pitch and roll) must be simulated with the airplane trimmed...

  14. 14 CFR 25.253 - High-speed characteristics.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false High-speed characteristics. 25.253 Section...-speed characteristics. (a) Speed increase and recovery characteristics. The following speed increase and... inadvertent speed increases (including upsets in pitch and roll) must be simulated with the airplane trimmed...

  15. Difference in rural and urban driver-injury severities in highway-rail grade crossing accidents.

    PubMed

    Hao, Wei; Kamga, Camille

    2015-09-22

    Based on the Federal Railway Administration (FRA) database, there were 25,945 highway-rail crossing accidents in the United States between 2002 and 2011. With an extensive research, analysis results showed that there were substantial differences between rural and urban areas at highway-rail grade crossings. However, there is no published study specific on driver's injury severity at highway-rail grade crossings classified by area types. Using an ordered probit modelling approach, the study explores the determinants of driver-injury severity at rural highway-rail grade crossings compared with urban highway-rail grade crossings. The analysis found that motor vehicle driver's injury level at rural highway-rail grade crossing is extremely higher than urban area. Compared to collisions at urban area, collisions happened at rural area tend to result in more severe injuries. These crashes were more prevalent if vehicle drivers are driving at a high speed or the oncoming trains are high-speed. Moreover, highway-rail grade crossing accidents were more likely to occur at rural area without pavement and lighting.

  16. Military Fuel and Alternative Fuel Effects on a Modern Diesel Engine Employing a Fuel-Lubricated High Pressure Common Rail Fuel Injection System

    DTIC Science & Technology

    2011-08-09

    injected, turbo- charged, air- water intercooled engine which employs a fuel- lubricated high pressure common rail pump , and piezo- electric fuel injectors...military fuels. Many of these modern HPCR systems utilize fuel-lubricated high pressure pumps , and can generate upwards of 2000-bar fuel rail pressures...steps were allowed to meet their own steady state temperatures. In addition, engine oil sump temperature was dictated by an internal jacket water

  17. Influences of aerodynamic loads on hunting stability of high-speed railway vehicles and parameter studies

    NASA Astrophysics Data System (ADS)

    Zeng, Xiao-Hui; Wu, Han; Lai, Jiang; Sheng, Hong-Zhi

    2014-12-01

    The influences of steady aerodynamic loads on hunting stability of high-speed railway vehicles were investigated in this study. A mechanism is suggested to explain the change of hunting behavior due to actions of aerodynamic loads: the aerodynamic loads can change the position of vehicle system (consequently the contact relations), the wheel/rail normal contact forces, the gravitational restoring forces/moments and the creep forces/moments. A mathematical model for hunting stability incorporating such influences was developed. A computer program capable of incorporating the effects of aerodynamic loads based on the model was written, and the critical speeds were calculated using this program. The dependences of linear and nonlinear critical speeds on suspension parameters considering aerodynamic loads were analyzed by using the orthogonal test method, the results were also compared with the situations without aerodynamic loads. It is shown that the most dominant factors affecting linear and nonlinear critical speeds are different whether the aerodynamic loads considered or not. The damping of yaw damper is the most dominant influencing factor for linear critical speeds, while the damping of lateral damper is most dominant for nonlinear ones. When the influences of aerodynamic loads are considered, the linear critical speeds decrease with the rise of crosswind velocity, whereas it is not the case for the nonlinear critical speeds. The variation trends of critical speeds with suspension parameters can be significantly changed by aerodynamic loads. Combined actions of aerodynamic loads and suspension parameters also affect the critical speeds. The effects of such joint action are more obvious for nonlinear critical speeds.

  18. Cryogenic, high speed, turbopump bearing cooling requirements

    NASA Technical Reports Server (NTRS)

    Dolan, Fred J.; Gibson, Howard G.; Cannon, James L.; Cody, Joe C.

    1988-01-01

    Although the Space Shuttle Main Engine (SSME) has repeatedly demonstrated the capability to perform during launch, the High Pressure Oxidizer Turbopump (HPOTP) main shaft bearings have not met their 7.5 hour life requirement. A tester is being employed to provide the capability of subjecting full scale bearings and seals to speeds, loads, propellants, temperatures, and pressures which simulate engine operating conditions. The tester design permits much more elaborate instrumentation and diagnostics than could be accommodated in an SSME turbopump. Tests were made to demonstrate the facilities; and the devices' capabilities, to verify the instruments in its operating environment and to establish a performance baseline for the flight type SSME HPOTP Turbine Bearing design. Bearing performance data from tests are being utilized to generate: (1) a high speed, cryogenic turbopump bearing computer mechanical model, and (2) a much improved, very detailed thermal model to better understand bearing internal operating conditions. Parametric tests were also made to determine the effects of speed, axial loads, coolant flow rate, and surface finish degradation on bearing performance.

  19. Pressure Distribution Over Airfoils at High Speeds

    NASA Technical Reports Server (NTRS)

    Briggs, L J; Dryden, H L

    1927-01-01

    This report deals with the pressure distribution over airfoils at high speeds, and describes an extension of an investigation of the aerodynamic characteristics of certain airfoils which was presented in NACA Technical Report no. 207. The results presented in report no. 207 have been confirmed and extended to higher speeds through a more extensive and systematic series of tests. Observations were also made of the air flow near the surface of the airfoils, and the large changes in lift coefficients were shown to be associated with a sudden breaking away of the flow from the upper surface. The tests were made on models of 1-inch chord and comparison with the earlier measurements on models of 3-inch chord shows that the sudden change in the lift coefficient is due to compressibility and not to a change in the Reynolds number. The Reynolds number still has a large effect, however, on the drag coefficient. The pressure distribution observations furnish the propeller designer with data on the load distribution at high speeds, and also give a better picture of the air-flow changes.

  20. High-speed multichannel optical switching

    SciTech Connect

    Mikaelian, A.L.; Salakhutdinov, V.K.

    1994-12-31

    The programmable interconnection between N input and N output channels based on a matrix of microholograms is considered. Such a system can be used for optical switching having high speed, about gigabits-per-second. An example of such a system using bacteriorhodopsin film is investigated both theoretically and experimentally. The thickness of bacteriorhodopsin was 50 {micro}m and the cell size 3cmx2cm. To maintain interconnects each microhologram was regenerated by means of a routing system composed of a He-Ne laser, deflectors and optical elements. Experimentally, 20 channels were used. The diameter of the microhologram was 1 mm, and the diffraction efficiency was about 2%. The tests and calculations show the possibility of arranging 10{sup 4} switching channels with speed about 1 gigabit per second.

  1. Wheel-rail dynamic forces induced by random vertical track irregularities

    NASA Astrophysics Data System (ADS)

    Spiroiu, M. A.

    2016-08-01

    The present paper investigates the wheel-rail dynamic forces produced by railway vehicles in motion, which are an important issue especially for the high-speed rail transport from the point of view of traffic safety, ride quality and undesirable effects on vehicles, on track and on the land in the vicinity of railways. The research is carried out on a model which includes track system, vehicle unsprung mass, vehicle primary suspension and the bogie sprung mass. The wheel-rail dynamic overloads are evaluated assuming random vertical irregularities of the track. The estimation of wheel-rail dynamic forces is made for a range of vehicle speeds up to 300 km/h and the influence of track and vehicle various parameters is investigated.

  2. Thermomechanical phenomena in high speed rubbing

    NASA Technical Reports Server (NTRS)

    Kennedy, F. E.

    1980-01-01

    An analytical approach is presented for the modeling of the thermomechanical interactions which occur in high speed sliding situations. These sliding contact problems which are characterized by active and interrelated thermal and mechanical phenomena could be called 'rub energetics' problems. Analytical models were developed to simulate two different rub situations: high energy braking of disk brakes and high speed rubs of gas path seals in turbine engines. The models proved to be particularly useful in predicting the severe temperatures and deformations near hot contact patches on the rubbing surfaces. The size of the hot patches is generally determined by normal load and the properties of the contacting materials. Temperatures at the contact patches can approach the melting point of the materials, especially at high sliding velocities. These high temperatures can lead to large amounts of near-surface deformation and high wear rates. Decreased contact temperatures can result from using materials with increased thermal conductivity and increased heat capacity or choosing mechanical properties (decreased stiffness, yield stress or coefficient of thermal expansion) which give larger hot spot size.

  3. High-Speed Propeller for Aircraft

    NASA Technical Reports Server (NTRS)

    Sagerser, D. A.; Gatzen, B. S.

    1986-01-01

    Engine efficiency increased. Propeller blades required to be quite thin and highly swept to minimize compressibility losses and propeller noise during high-speed cruise. Use of 8 or 10 blades with highpropeller-power loading allows overall propeller diameter to be kept relatively small. Area-ruled spinner and integrated nacelle shape reduce compressibility losses in propeller hub region. Finally, large modern turboshaft engine and gearbox provide power to advanced propeller. Fuel savings of 30 to 50 percent over present systems anticipated. Propfan system adaptable to number of applications, such as highspeed (subsonic) business and general-aviation aircraft, and military aircraft including V/STOL.

  4. An SAE high speed ring bus overview

    NASA Astrophysics Data System (ADS)

    Kroeger, Brian W.; Shih, Hubert

    An overview of the protocols and important features of the SAE high-speed ring bus (HSRB) standard is presented here, along with the functional design of a typical ring interface unit architecture. The counterrotating ring topology, with both loopback and bypass mechanisms, provides the high degree of fault tolerance desirable in many military and avionic systems. The error-detection, fault-detection, and recovery mechanisms are briefly described to illustrate the robustness of the HSRB system. The reserved-priority token-passing protocol is shown to provide efficient and deterministic performance, uselful in real-time applications where messages must be transmitted predictably, quickly, and reliably.

  5. Conclusions from high-speed rotorcraft studies

    NASA Technical Reports Server (NTRS)

    Conway, Scott

    1991-01-01

    Under the tutelage of NASA-Ames, evaluations have been made of the technology required for high-speed rotorcraft flight with a view to the performance potential and development risks of several candidate configurations. Configurational performance limitations were associated with rotor performance at high Mach numbers and advance ratios, nacelle interference effects on rotor flow, and wing/rotor aeroelastic stability requirements. Attention is given to tiltwing, tilt-for-VTOL/fold-for-cruise rotor, and conventional tiltrotor configurations capable of carrying 30 passengers for the intercity commuter market.

  6. High-Speed, high-power, switching transistor

    NASA Technical Reports Server (NTRS)

    Carnahan, D.; Ohu, C. K.; Hower, P. L.

    1979-01-01

    Silicon transistor rate for 200 angstroms at 400 to 600 volts combines switching speed of transistors with ruggedness, power capacity of thyristor. Transistor introduces unique combination of increased power-handling capability, unusally low saturation and switching losses, and submicrosecond switching speeds. Potential applications include high power switching regulators, linear amplifiers, chopper controls for high frequency electrical vehicle drives, VLF transmitters, RF induction heaters, kitchen cooking ranges, and electronic scalpels for medical surgery.

  7. High-speed high-efficiency photodetectors based on heterostructures

    NASA Astrophysics Data System (ADS)

    Korolkov, V. I.

    Recent advances in the development of high-speed high-efficiency heterostructure photodetectors (HPs) are reviewed. It is noted that the performance of semiconductor photodetectors has been improved by forbidden bandwidth control. Various types of HPs are examined, including modifications of heterophotodiodes and detectors with internal amplification; avalanche photodiodes; bipolar phototransistors; and planar photoresistance devices and field-effect phototransistors. These devices are compared in terms of speed and efficiency.

  8. High-Speed, high-power, switching transistor

    NASA Technical Reports Server (NTRS)

    Carnahan, D.; Ohu, C. K.; Hower, P. L.

    1979-01-01

    Silicon transistor rate for 200 angstroms at 400 to 600 volts combines switching speed of transistors with ruggedness, power capacity of thyristor. Transistor introduces unique combination of increased power-handling capability, unusally low saturation and switching losses, and submicrosecond switching speeds. Potential applications include high power switching regulators, linear amplifiers, chopper controls for high frequency electrical vehicle drives, VLF transmitters, RF induction heaters, kitchen cooking ranges, and electronic scalpels for medical surgery.

  9. Exhaust emissions from high speed passenger ferries

    NASA Astrophysics Data System (ADS)

    Cooper, D. A.

    Exhaust emission measurements have been carried out on-board three high-speed passenger ferries (A, B and C) during normal service routes. Ship A was powered by conventional, medium-speed, marine diesel engines, Ship B by gas turbine engines and Ship C conventional, medium-speed, marine diesel engines equipped with selective catalytic reduction (SCR) systems for NO x abatement. All ships had similar auxiliary engines (marine diesels) for generating electric power on-board. Real-world emission factors of NOx, SO2, CO, CO 2, NMVOC, CH4, N2O, NH3, PM and PAH at steady-state engine loads and for complete voyages were determined together with an estimate of annual emissions. In general, Ship B using gas turbines showed favourable NO x, PM and PAH emissions but at the expense of higher fuel consumption and CO 2 emissions. Ship C with the SCR had the lowest NO x emissions but highest NH 3 emissions especially during harbour approaches and stops. The greatest PM and PAH specific emissions were measured from auxiliary engines operating at low engine loads during harbour stops. Since all ships used a low-sulphur gas oil, SO 2 emissions were relatively low in all cases.

  10. High-speed Civil Transport Aircraft Emissions

    NASA Technical Reports Server (NTRS)

    Miake-Lye, Richard C.; Matulaitis, J. A.; Krause, F. H.; Dodds, Willard J.; Albers, Martin; Hourmouziadis, J.; Hasel, K. L.; Lohmann, R. P.; Stander, C.; Gerstle, John H.

    1992-01-01

    Estimates are given for the emissions from a proposed high speed civil transport (HSCT). This advanced technology supersonic aircraft would fly in the lower stratosphere at a speed of roughly Mach 1.6 to 3.2 (470 to 950 m/sec or 920 to 1850 knots). Because it would fly in the stratosphere at an altitude in the range of 15 to 23 km commensurate with its design speed, its exhaust effluents could perturb the chemical balance in the upper atmosphere. The first step in determining the nature and magnitude of any chemical changes in the atmosphere resulting from these proposed aircraft is to identify and quantify the chemically important species they emit. Relevant earlier work is summarized, dating back to the Climatic Impact Assessment Program of the early 1970s and current propulsion research efforts. Estimates are provided of the chemical composition of an HSCT's exhaust, and these emission indices are presented. Other aircraft emissions that are not due to combustion processes are also summarized; these emissions are found to be much smaller than the exhaust emissions. Future advances in propulsion technology, in experimental measurement techniques, and in understanding upper atmospheric chemistry may affect these estimates of the amounts of trace exhaust species or their relative importance.

  11. Rail Access to Yucca Mountain: Critical Issues

    SciTech Connect

    Halstead, R. J.; Dilger, F.; Moore, R. C.

    2003-02-25

    The proposed Yucca Mountain repository site currently lacks rail access. The nearest mainline railroad is almost 100 miles away. Absence of rail access could result in many thousands of truck shipments of spent nuclear fuel and high-level radioactive waste. Direct rail access to the repository could significantly reduce the number of truck shipments and total shipments. The U.S. Department of Energy (DOE) identified five potential rail access corridors, ranging in length from 98 miles to 323 miles, in the Final Environmental Impact Statement (FEIS) for Yucca Mountain. The FEIS also considers an alternative to rail spur construction, heavy-haul truck (HHT) delivery of rail casks from one of three potential intermodal transfer stations. The authors examine the feasibility and cost of the five rail corridors, and DOE's alternative proposal for HHT transport. The authors also address the potential for rail shipments through the Las Vegas metropolitan area.

  12. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed increase and recovery characteristics must be met: (a) Operating...

  13. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed increase and recovery characteristics must be met: (a) Operating...

  14. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. Link to an amendment published at 76 FR 75755, December 2, 2011. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed...

  15. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed increase and recovery characteristics must be met: (a) Operating...

  16. Flow imaging by high speed transmission tomography.

    PubMed

    Johansen, Geir Anton; Hampel, Uwe; Hjertaker, Bjørn Tore

    2010-01-01

    Fourth generation medical X-ray scanners using a gantry with a rotating X-ray source and a fixed circular detector array as sensor head, are too slow for imaging of the process dynamics for instance in multiphase flows. To avoid inconsistent measurements and motion blurring, all measurements need to be carried out in a short time compared to the time constants of the process dynamics. Two different high speed tomographic imaging systems are presented here demonstrating that image rates of several thousand images per second is possible. Copyright 2009 Elsevier Ltd. All rights reserved.

  17. Characterization and Compensation of High Speed Digitizers

    SciTech Connect

    Fong, P; Teruya, A; Lowry, M

    2005-04-04

    Increasingly, ADC technology is being pressed into service for single single-shot instrumentation applications that were formerly served by vacuum-tube based oscilloscopes and streak cameras. ADC technology, while convenient, suffers significant performance impairments. Thus, in these demanding applications, a quantitative and accurate representation of these impairments is critical to an understanding of measurement accuracy. We have developed a phase-plane behavioral model, implemented it in SIMULINK and applied it to interleaved, high-speed ADCs (up to 4 gigasamples/sec). We have also developed and demonstrated techniques to effectively compensate for these impairments based upon the model.

  18. High Speed Solid State Circuit Breaker

    NASA Technical Reports Server (NTRS)

    Podlesak, Thomas F.

    1993-01-01

    The U.S. Army Research Laboratory, Fort Monmouth, NJ, has developed and is installing two 3.3 MW high speed solid state circuit breakers at the Army's Pulse Power Center. These circuit breakers will interrupt 4160V three phase power mains in no more than 300 microseconds, two orders of magnitude faster than conventional mechanical contact type circuit breakers. These circuit breakers utilize Gate Turnoff Thyristors (GTO's) and are currently utility type devices using air cooling in an air conditioned enclosure. Future refinements include liquid cooling, either water or two phase organic coolant, and more advanced semiconductors. Each of these refinements promises a more compact, more reliable unit.

  19. The Hubble Space Telescope high speed photometer

    NASA Technical Reports Server (NTRS)

    Vancitters, G. W., Jr.; Bless, R. C.; Dolan, J. F.; Elliot, J. L.; Robinson, E. L.; White, R. L.

    1988-01-01

    The Hubble Space Telescope will provide the opportunity to perform precise astronomical photometry above the disturbing effects of the atmosphere. The High Speed Photometer is designed to provide the observatory with a stable, precise photometer with wide dynamic range, broad wavelenth coverage, time resolution in the microsecond region, and polarimetric capability. Here, the scientific requirements for the instrument are examined, the unique design features of the photometer are explored, and the improvements to be expected over the performance of ground-based instruments are projected.

  20. Finite element methods for high speed flows

    NASA Technical Reports Server (NTRS)

    Loehner, R.; Morgan, K.; Peraire, J.; Zienkiewicz, O. C.

    1985-01-01

    An explicit finite element based solution procedure for solving the equations of compressible viscous high speed flow is presented. The method uses domain splitting to advance the solution with different timesteps on different portions of the mesh. For steady inviscid flows, adaptive mesh refinement procedures are successfully employed to enhance the definition of discontinuities. Preliminary ideas on the application of adaptive mesh refinement to the solution of problems involving steady viscous flow are presented. Sample timings are given for the performance of the finite element code on modern supercomputers.

  1. Continuous QKD and high speed data encryption

    NASA Astrophysics Data System (ADS)

    Zbinden, Hugo; Walenta, Nino; Guinnard, Olivier; Houlmann, Raphael; Wen, Charles Lim Ci; Korzh, Boris; Lunghi, Tommaso; Gisin, Nicolas; Burg, Andreas; Constantin, Jeremy; Legré, Matthieu; Trinkler, Patrick; Caselunghe, Dario; Kulesza, Natalia; Trolliet, Gregory; Vannel, Fabien; Junod, Pascal; Auberson, Olivier; Graf, Yoan; Curchod, Gilles; Habegger, Gilles; Messerli, Etienne; Portmann, Christopher; Henzen, Luca; Keller, Christoph; Pendl, Christian; Mühlberghuber, Michael; Roth, Christoph; Felber, Norbert; Gürkaynak, Frank; Schöni, Daniel; Muheim, Beat

    2013-10-01

    We present the results of a Swiss project dedicated to the development of high speed quantum key distribution and data encryption. The QKD engine features fully automated key exchange, hardware key distillation based on finite key security analysis, efficient authentication and wavelength division multiplexing of the quantum and the classical channel and one-time pas encryption. The encryption device allows authenticated symmetric key encryption (e.g AES) at rates of up to 100 Gb/s. A new quantum key can uploaded up to 1000 times second from the QKD engine.

  2. High-speed multispectral confocal biomedical imaging

    PubMed Central

    Carver, Gary E.; Locknar, Sarah A.; Morrison, William A.; Krishnan Ramanujan, V.; Farkas, Daniel L.

    2014-01-01

    Abstract. A new approach for generating high-speed multispectral confocal images has been developed. The central concept is that spectra can be acquired for each pixel in a confocal spatial scan by using a fast spectrometer based on optical fiber delay lines. This approach merges fast spectroscopy with standard spatial scanning to create datacubes in real time. The spectrometer is based on a serial array of reflecting spectral elements, delay lines between these elements, and a single element detector. The spatial, spectral, and temporal resolution of the instrument is described and illustrated by multispectral images of laser-induced autofluorescence in biological tissues. PMID:24658777

  3. Non-contact rail flaw detection system: first field test

    NASA Astrophysics Data System (ADS)

    Rizzo, Piervincenzo; Coccia, Stefano; Lanza di Scalea, Francesco; Bartoli, Ivan; Fateh, Mahmood

    2007-04-01

    Researchers at UCSD, with the initial support of NSF and the current support of the Federal Railroad Administration (FRA), have been working on a flaw detection prototype for rails that uses non-contact ultrasonic probing and robust data processing algorithms to provide high speed and high reliability defect detection in these structures. Besides the obvious advantages of non-contact probing, the prototype uses ultrasonic guided waves able to detect and quantify transverse cracks in the rail head, notoriously the most dangerous of all rail track defects. This paper will report on the first field test which was conducted in Gettysburg, PA in March 2006 with the technical support of ENSCO, Inc. Good results were obtained for the detection of both surface-breaking and internal cracks ranging in size from 2% cross-sectional head area (H.A.) reduction to 80% H.A. reduction.

  4. Study of high-speed civil transports

    NASA Technical Reports Server (NTRS)

    1989-01-01

    A systems study to identify the economic potential for a high-speed commercial transport (HSCT) has considered technology, market characteristics, airport infrastructure, and environmental issues. Market forecasts indicate a need for HSCT service in the 2000/2010 time frame conditioned on economic viability and environmental acceptability. Design requirements focused on a 300 passenger, 3 class service, and 6500 nautical mile range based on the accelerated growth of the Pacific region. Compatibility with existing airports was an assumed requirement. Mach numbers between 2 and 25 were examined in conjunction with the appropriate propulsion systems, fuels, structural materials, and thermal management systems. Aircraft productivity was a key parameter with aircraft worth, in comparison to aircraft price, being the airline-oriented figure of merit. Aircraft screening led to determination that Mach 3.2 (TSJF) would have superior characteristics to Mach 5.0 (LNG) and the recommendation that the next generation high-speed commercial transport aircraft use a kerosene fuel. The sensitivity of aircraft performance and economics to environmental constraints (e.g., sonic boom, engine emissions, and airport/community noise) was identified together with key technologies. In all, current technology is not adequate to produce viable HSCTs for the world marketplace. Technology advancements must be accomplished to meet environmental requirements (these requirements are as yet undetermined for sonic boom and engine emissions). High priority is assigned to aircraft gross weight reduction which benefits both economics and environmental aspects. Specific technology requirements are identified and national economic benefits are projected.

  5. Applications for high-speed infrared imaging

    NASA Astrophysics Data System (ADS)

    Richards, Austin A.

    2005-03-01

    The phrase high-speed imaging is generally associated with short exposure times, fast frame rates or both. Supersonic projectiles, for example, are often impossible to see with the unaided eye, and require strobe photography to stop their apparent motion. It is often necessary to image high-speed objects in the infrared region of the spectrum, either to detect them or to measure their surface temperature. Conventional infrared cameras have time constants similar to the human eye, so they too, are often at a loss when it comes to photographing fast-moving hot targets. Other types of targets or scenes such as explosions change very rapidly with time. Visualizing those changes requires an extremely high frame rate combined with short exposure times in order to slow down a dynamic event so that it can be studied and quantified. Recent advances in infrared sensor technology and computing power have pushed the envelope of what is possible to achieve with commercial IR camera systems.

  6. TOPICAL REVIEW: Plasmas in high speed aerodynamics

    NASA Astrophysics Data System (ADS)

    Bletzinger, P.; Ganguly, B. N.; Van Wie, D.; Garscadden, A.

    2005-02-01

    A review is presented of the studies in the former Soviet Union and in the USA of the mutual interactions of plasmas and high speed flows and shocks. There are reports from as early as the 1980s of large changes in the standoff distance ahead of a blunt body in ballistic tunnels, significantly reduced drag and modifications of travelling shocks in bounded weakly ionized gases. Energy addition to the flow results in an increase in the local sound speed that leads to expected modifications of the flow and changes to the pressure distribution around a vehicle due to the decrease in local Mach number. The critical question was, did a plasma provide a significant energy multiplier for the system? There have been a large number of experimental studies on the influence of a weakly ionized plasma on relatively low Mach number shocks and inherently also on the influence of the shock on the plasma. This literature is reviewed and illustrated with representative examples. The convergence through more controlled experiments and improved modelling to a physics understanding of the effects being essentially due to heating is outlined. It is demonstrated that the heating in many cases is global; however, tailored experiments with positive columns, dielectric barrier discharges and focused microwave plasmas can produce very localized heating. The latter appears more attractive for energy efficiency in flow control. Tailored localized ionization and thermal effects are also of interest for high speed inlet shock control and for producing reliable ignition for short residence time combustors, and work in these areas is also reviewed.

  7. Modelling the effect of rail dampers on wheel-rail interaction forces and rail roughness growth rates

    NASA Astrophysics Data System (ADS)

    Croft, B. E.; Jones, C. J. C.; Thompson, D. J.

    2009-06-01

    Trains generate rolling noise because of the roughness of the wheel and rail running surfaces. Special acoustic grinding programmes have been introduced on some railways specifically to control rolling noise. Rail dampers are also used to reduce rolling noise; this paper studies rail damping as a possible mechanism to slow the rate of development of roughness on the surface of rails. This would reduce noise further over time or reduce the required frequency of grinding. High roughness growth on the rail occurs in situations with stiff vertical structural dynamics of the track. In particular the antiresonance above a sleeper at the pinned-pinned frequency has been identified as a wavelength fixing mechanism for short pitch corrugation. Rail dampers change the dynamic response of the rail, shifting the pinned-pinned frequency and smoothing the track receptance. Here, a simple time-stepping model is applied to calculate the interaction forces between wheel and rail for a track with and without rail dampers. The calculations show that rail dampers reduce dynamic interaction forces and shift the force spectrum to longer wavelengths. The interaction forces are used as input to an abrasive wear model to predict the roughness growth rate and the change in roughness after many wheel passages. Track without rail dampers is predicted to develop corrugation at the wavelength corresponding to the pinned-pinned frequency. With rail dampers the corrugation growth is reduced and shifted to a longer wavelength where its significance is diminished.

  8. Nanopatterned Quantum Dot Lasers for High Speed, High Efficiency, Operation

    DTIC Science & Technology

    2015-04-27

    SECURITY CLASSIFICATION OF: Quantum dot (QD) active regions hold potential for realizing extremely high performance semiconductor diode lasers...2009 31-Dec-2014 Approved for Public Release; Distribution Unlimited Final Report: Nanopatterned Quantum Dot Lasers for High Speed, High Efficiency...Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 quantum dots , nanopatterning, MOCVD, laser REPORT DOCUMENTATION PAGE 11

  9. ACTS High-Speed VSAT Demonstrated

    NASA Technical Reports Server (NTRS)

    Tran, Quang K.

    1999-01-01

    The Advanced Communication Technology Satellite (ACTS) developed by NASA has demonstrated the breakthrough technologies of Ka-band transmission, spot-beam antennas, and onboard processing. These technologies have enabled the development of very small and ultrasmall aperture terminals (VSAT s and USAT's), which have capabilities greater than have been possible with conventional satellite technologies. The ACTS High Speed VSAT (HS VSAT) is an effort at the NASA Glenn Research Center at Lewis Field to experimentally demonstrate the maximum user throughput data rate that can be achieved using the technologies developed and implemented on ACTS. This was done by operating the system uplinks as frequency division multiple access (FDMA), essentially assigning all available time division multiple access (TDMA) time slots to a single user on each of two uplink frequencies. Preliminary results show that, using a 1.2-m antenna in this mode, the High Speed VSAT can achieve between 22 and 24 Mbps of the 27.5 Mbps burst rate, for a throughput efficiency of 80 to 88 percent.

  10. High-speed optogenetic circuit mapping

    NASA Astrophysics Data System (ADS)

    Augustine, George J.; Chen, Susu; Gill, Harin; Katarya, Malvika; Kim, Jinsook; Kudolo, John; Lee, Li M.; Lee, Hyunjeong; Lo, Shun Qiang; Nakajima, Ryuichi; Park, Min-Yoon; Tan, Gregory; Tang, Yanxia; Teo, Peggy; Tsuda, Sachiko; Wen, Lei; Yoon, Su-In

    2013-03-01

    Scanning small spots of laser light allows mapping of synaptic circuits in brain slices from transgenic mice expressing channelrhodopsin-2 (ChR2). These light spots photostimulate presynaptic neurons expressing ChR2, while postsynaptic responses can be monitored in neurons that do not express ChR2. Correlating the location of the light spot with the amplitude of the postsynaptic response elicited at that location yields maps of the spatial organization of the synaptic circuits. This approach yields maps within minutes, which is several orders of magnitude faster than can be achieved with conventional paired electrophysiological methods. We have applied this high-speed technique to map local circuits in many brain regions. In cerebral cortex, we observed that maps of excitatory inputs to pyramidal cells were qualitatively different from those measured for interneurons within the same layers of the cortex. In cerebellum, we have used this approach to quantify the convergence of molecular layer interneurons on to Purkinje cells. The number of converging interneurons is reduced by treatment with gap junction blockers, indicating that electrical synapses between interneurons contribute substantially to the spatial convergence. Remarkably, gap junction blockers affect convergence in sagittal cerebellar slices but not in coronal slices, indicating sagittal polarization of electrical coupling between interneurons. By measuring limb movement or other forms of behavioral output, this approach also can be used in vivo to map brain circuits non-invasively. In summary, ChR2-mediated high-speed mapping promises to revolutionize our understanding of brain circuitry.

  11. Development of a simulation model for dynamic derailment analysis of high-speed trains

    NASA Astrophysics Data System (ADS)

    Ling, Liang; Xiao, Xin-Biao; Jin, Xue-Song

    2014-12-01

    The running safety of high-speed trains has become a major concern of the current railway research with the rapid development of high-speed railways around the world. The basic safety requirement is to prevent the derailment. The root causes of the dynamic derailment of high-speed trains operating in severe environments are not easy to identify using the field tests or laboratory experiments. Numerical simulation using an advanced train-track interaction model is a highly efficient and low-cost approach to investigate the dynamic derailment behavior and mechanism of high-speed trains. This paper presents a three-dimensional dynamic model of a high-speed train coupled with a ballast track for dynamic derailment analysis. The model considers a train composed of multiple vehicles and the nonlinear inter-vehicle connections. The ballast track model consists of rails, fastenings, sleepers, ballasts, and roadbed, which are modeled by Euler beams, nonlinear spring-damper elements, equivalent ballast bodies, and continuous viscoelastic elements, in which the modal superposition method was used to reduce the order of the partial differential equations of Euler beams. The commonly used derailment safety assessment criteria around the world are embedded in the simulation model. The train-track model was then used to investigate the dynamic derailment responses of a high-speed train passing over a buckled track, in which the derailment mechanism and train running posture during the dynamic derailment process were analyzed in detail. The effects of train and track modelling on dynamic derailment analysis were also discussed. The numerical results indicate that the train and track modelling options have a significant effect on the dynamic derailment analysis. The inter-vehicle impacts and the track flexibility and nonlinearity should be considered in the dynamic derailment simulations.

  12. Driver speed selection on high-speed two-lane highways: Comparing speed profiles between uniform and differential speed limits.

    PubMed

    Russo, Brendan J; Savolainen, Peter T; Gates, Timothy J; Kay, Jonathan J; Frazier, Sterling

    2017-07-04

    Although a considerable amount of prior research has investigated the impacts of speed limits on traffic safety and operations, much of this research, and nearly all of the research related to differential speed limits, has been specific to limited access freeways. The unique safety and operational issues on highways without access control create difficulty relating the conclusions from prior freeway-related speed limit research to 2-lane highways, particularly research on differential limits due to passing limitations and subsequent queuing. Therefore, the objective of this study was to assess differences in driver speed selection with respect to the posted speed limit on rural 2-lane highways, with a particular emphasis on the differences between uniform and differential speed limits. Data were collected from nearly 59,000 vehicles across 320 sites in Montana and 4 neighboring states. Differences in mean speeds, 85th percentile speeds, and the standard deviation in speeds for free-flowing vehicles were examined across these sites using ordinary least squares regression models. Ultimately, the results of the analysis show that the mean speed, 85th percentile speed, and variability in travel speeds for free-flowing vehicles on 2-lane highways are generally lower at locations with uniform 65 mph speed limits, compared to locations with differential limits of 70 mph for cars and 60 mph for trucks. In addition to posted speed limits, several site characteristics were shown to influence speed selection including shoulder widths, frequency of horizontal curves, percentage of the segment that included no passing zones, and hourly volumes. Differences in vehicle speed characteristics were also observed between states, indicating that speed selection may also be influenced by local factors, such as driver population or enforcement.

  13. High-speed spatial scanning pyrometer

    NASA Technical Reports Server (NTRS)

    Cezairliyan, A.; Chang, R. F.; Foley, G. M.; Miller, A. P.

    1993-01-01

    A high-speed spatial scanning pyrometer has been designed and developed to measure spectral radiance temperatures at multiple target points along the length of a rapidly heating/cooling specimen in dynamic thermophysical experiments at high temperatures (above about 1800 K). The design, which is based on a self-scanning linear silicon array containing 1024 elements, enables the pyrometer to measure spectral radiance temperatures (nominally at 650 nm) at 1024 equally spaced points along a 25-mm target length. The elements of the array are sampled consecutively every 1 microsec, thereby permitting one cycle of measurements to be completed in approximately 1 msec. Procedures for calibration and temperature measurement as well as the characteristics and performance of the pyrometer are described. The details of sources and estimated magnitudes of possible errors are given. An example of measurements of radiance temperatures along the length of a tungsten rod, during its cooling following rapid resistive pulse heating, is presented.

  14. Very high-speed digital holography

    NASA Astrophysics Data System (ADS)

    Pérez López, Carlos; Mendoza Santoyo, Fernando; Rodríguez Vera, Ramón; Moreno, David; Barrientos, Bernardino

    2006-08-01

    It is reported for the first time the use of a high speed camera in digital holography with an out of plane sensitivity. The camera takes the image plane holograms of a cw laser illuminated rectangular framed polyester material at a rate of 5000 per second, that is a spacing of 200 microseconds between holograms, and 512 by 500 pixels at 10 bit resolution. The freely standing object has a random movement due to non controlled environmental air currents. As is usual with this technique each digital hologram is Fourier processed in order to obtain upon comparison with a consecutive digital hologram the phase map of the displacement. High quality results showing the amplitude and direction of the random movement are presented.

  15. Interpolation circuit with high resolution and high response speed

    NASA Astrophysics Data System (ADS)

    Piao, Weiying; Yuan, Yibao; Xu, Lianhu; Zhang, Hao

    2009-05-01

    An interpolation circuit based upon the looking-up table by hardware is presented. Output data of two A/D convertors are connected to ROM's address bus. The memory space of ROM is divided. When the address bus is activated by A/D conversion's output data, the ROM's output data is interpolation data. This circuit has high response speed, and it is easy to obtain high interpolation multiple. The same kind of hardware circuit can achieve different interpolation multiple by modifying ROM's data. It is very convenient and flexible. The principle of direction judgment and counting is analyzed; the implementation speed and maximal interpolation multiple are discussed in this paper. Finally through experiment, make sure this circuit not only has the characteristic of high response speed and high interpolation multiple, but also avoids the counting error of micro-computer interpolation.

  16. Visualization of high speed phenomena using high-speed infrared camera

    NASA Astrophysics Data System (ADS)

    Yaoita, T.; Marcotte, F.

    2017-02-01

    The standard infrared camera has taken certain integration time with the photography per once, it was unsuitable for high-speed photography. By the infrared camera which can buffer photography data efficiently continually, high-speed photography of 2,000fps is enabled in 320X240 pixels and 11,000fps in128X100 pixels by windowing mode. The heat generation of specimen phenomenon is used for the monitoring of the start point of the destruction and the thermometry of combustion gases.

  17. High-speed ACR/NEMA interface

    NASA Astrophysics Data System (ADS)

    Reijns, Gerard L.; Santilli, D.; Schellingerhout, G.; Jochem, A. J.; Ottes, Fenno P.; van Aken, I. W.

    1990-08-01

    The design and implementation of a standard high speed ACR-NEMA communications interface is described. The upper layers e.g. the Presentation layer, Session layer and part of the Transport/Network layer have been implemented in software. In order to reach the speed requirement of 8M byte/sec. the lower layers e.g. part of the Transport/Network layer and Data Link layer have been implemented in hardware. We have developed and built an interface for an IBM personal computer P5/2 model 50, working under the operating system OS/2. The PS/2, model 50 has been equipped with a fast micro-channel bus, which enables a large throughput. The operating systern OS/2 has a multitasking capability, which enables concurrent programming. In order to minimize the delays, we used this multitasking facility to create a number of parallel operating "threads". The Transport/Network layer functions have been implemented using a receive thread, two send threads and a device driver with three hardware registers. The time to transfer a packet by DMA, to initiate the DMA logic and to execute the required Kernal functions have each been measured and figures are shown. The Data Link layer provides for storage of two packets in two separate random access memories (RAM's). These two RAM's enable a pipelined operation, which minimizes the delay in the Data Link layer.

  18. High Speed Fibre Optic Backbone LAN

    NASA Astrophysics Data System (ADS)

    Tanimoto, Masaaki; Hara, Shingo; Kajita, Yuji; Kashu, Fumitoshi; Ikeuchi, Masaru; Hagihara, Satoshi; Tsuzuki, Shinji

    1987-09-01

    Our firm has developed the SUMINET-4100 series, a fibre optic local area network (LAN), to serve the communications system trunk line needs for facilities, such as steel refineries, automobile plants and university campuses, that require large transmission capacity, and for the backbone networks used in intelligent building systems. The SUMINET-4100 series is already in service in various fields of application. Of the networks available in this series, the SUMINET-4150 has a trunk line speed of 128 Mbps and the multiplexer used for time division multiplexing (TDM) was enabled by designing an ECL-TTL gate array (3000 gates) based custom LSI. The synchronous, full-duplex V.24 and V.3.5 interfaces (SUMINET-2100) are provided for use with general purpose lines. And the IBM token ring network, the SUMINET-3200, designed for heterogeneous PCs and the Ethernet can all be connected to sub loops. Further, the IBM 3270 TCA and 5080 CADAM can be connected in the local mode. Interfaces are also provided for the NTT high-speed digital service, the digital PBX systems, and the Video CODEC system. The built-in loop monitor (LM) and network supervisory processor (NSP) provide management of loop utilization and send loop status signals to the host CPU's network configuration and control facility (NCCF). These built-in functions allow both the computer system and LAN to be managed from a single source at the host. This paper outlines features of the SUMINET-4150 and provides an example of its installation.

  19. High-speed cameras at Los Alamos

    NASA Astrophysics Data System (ADS)

    Brixner, Berlyn

    1997-05-01

    In 1943, there was no camera with the microsecond resolution needed for research in Atomic Bomb development. We had the Mitchell camera (100 fps), the Fastax (10 000), the Marley (100 000), the drum streak (moving slit image) 10-5 s resolution, and electro-optical shutters for 10-6 s. Julian Mack invented a rotating-mirror camera for 10-7 s, which was in use by 1944. Small rotating mirror changes secured a resolution of 10-8 s. Photography of oscilloscope traces soon recorded 10-6 resolution, which was later improved to 10-8 s. Mack also invented two time resolving spectrographs for studying the radiation of the first atomic explosion. Much later, he made a large aperture spectrograph for shock wave spectra. An image dissecting drum camera running at 107 frames per second (fps) was used for studying high velocity jets. Brixner invented a simple streak camera which gave 10-8 s resolution. Using a moving film camera, an interferometer pressure gauge was developed for measuring shock-front pressures up to 100 000 psi. An existing Bowen 76-lens frame camera was speeded up by our turbine driven mirror to make 1 500 000 fps. Several streak cameras were made with writing arms from 4 1/2 to 40 in. and apertures from f/2.5 to f/20. We made framing cameras with top speeds of 50 000, 1 000 000, 3 500 000, and 14 000 000 fps.

  20. High-Speed RaPToRS

    NASA Astrophysics Data System (ADS)

    Henchen, Robert; Esham, Benjamin; Becker, William; Pogozelski, Edward; Padalino, Stephen; Sangster, Thomas; Glebov, Vladimir

    2008-11-01

    The High-Speed Rapid Pneumatic Transport of Radioactive Samples (HS-RaPToRS) system, designed to quickly and safely move radioactive materials, was assembled and tested at the Mercury facility of the Naval Research Laboratory (NRL) in Washington D.C. A sample, which is placed inside a four-inch-diameter carrier, is activated before being transported through a PVC tube via airflow. The carrier travels from the reaction chamber to the end station where it pneumatically brakes prior to the gate. A magnetic latch releases the gate when the carrier arrives and comes to rest. The airflow, optical carrier-monitoring devices, and end gate are controlled manually or automatically with LabView software. The installation and testing of the RaPToRS system at NRL was successfully completed with transport times of less than 3 seconds. The speed of the carrier averaged 16 m/s. Prospective facilities for similar systems include the Laboratory for Laser Energetics and the National Ignition Facility.

  1. Non-contact ultrasonic guided wave inspection of rails

    NASA Astrophysics Data System (ADS)

    Mariani, Stefano; Nguyen, Thompson V.; Phillips, Robert Ronald; Kijanka, Piotr; Lanza di Scalea, Francesco; Staszewski, Wieslaw Jerzy

    2013-04-01

    The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail integrity evaluation. A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection in pair with a real-time statistical analysis algorithm has been realized. This solution presents an improvement over the previously considered laser/air-coupled hybrid system because it replaces the costly and hard-to-maintain laser with a much cheaper, faster, and easier-to-maintain air-coupled transmitter. This system requires a specialized filtering approach due to the inherently poor signal-to-noise ratio of the air-coupled ultrasonic measurements in rail steel. Various aspects of the prototype have been designed with the aid of numerical analyses. In particular, simulations of ultrasonic guided wave propagation in rails have been performed using a LISA algorithm. Many of the system operating parameters were selected based on Receiver Operating Characteristic (ROC) curves, which provide a quantitative manner to evaluate different detection performances based on the trade-off between detection rate and false positive rate. Experimental tests have been carried out at the UCSD Rail Defect Farm. The laboratory results indicate that the prototype is able to detect internal rail defects with a high reliability. A field test will be planned later in the year to further validate these results. Extensions of the system are planned to add rail surface characterization to the internal rail defect detection.

  2. Using a High-Speed Camera to Measure the Speed of Sound

    ERIC Educational Resources Information Center

    Hack, William Nathan; Baird, William H.

    2012-01-01

    The speed of sound is a physical property that can be measured easily in the lab. However, finding an inexpensive and intuitive way for students to determine this speed has been more involved. The introduction of affordable consumer-grade high-speed cameras (such as the Exilim EX-FC100) makes conceptually simple experiments feasible. Since the…

  3. Using a High-Speed Camera to Measure the Speed of Sound

    ERIC Educational Resources Information Center

    Hack, William Nathan; Baird, William H.

    2012-01-01

    The speed of sound is a physical property that can be measured easily in the lab. However, finding an inexpensive and intuitive way for students to determine this speed has been more involved. The introduction of affordable consumer-grade high-speed cameras (such as the Exilim EX-FC100) makes conceptually simple experiments feasible. Since the…

  4. High speed operation of permanent magnet machines

    NASA Astrophysics Data System (ADS)

    El-Refaie, Ayman M.

    This work proposes methods to extend the high-speed operating capabilities of both the interior PM (IPM) and surface PM (SPM) machines. For interior PM machines, this research has developed and presented the first thorough analysis of how a new bi-state magnetic material can be usefully applied to the design of IPM machines. Key elements of this contribution include identifying how the unique properties of the bi-state magnetic material can be applied most effectively in the rotor design of an IPM machine by "unmagnetizing" the magnet cavity center posts rather than the outer bridges. The importance of elevated rotor speed in making the best use of the bi-state magnetic material while recognizing its limitations has been identified. For surface PM machines, this research has provided, for the first time, a clear explanation of how fractional-slot concentrated windings can be applied to SPM machines in order to achieve the necessary conditions for optimal flux weakening. A closed-form analytical procedure for analyzing SPM machines designed with concentrated windings has been developed. Guidelines for designing SPM machines using concentrated windings in order to achieve optimum flux weakening are provided. Analytical and numerical finite element analysis (FEA) results have provided promising evidence of the scalability of the concentrated winding technique with respect to the number of poles, machine aspect ratio, and output power rating. Useful comparisons between the predicted performance characteristics of SPM machines equipped with concentrated windings and both SPM and IPM machines designed with distributed windings are included. Analytical techniques have been used to evaluate the impact of the high pole number on various converter performance metrics. Both analytical techniques and FEA have been used for evaluating the eddy-current losses in the surface magnets due to the stator winding subharmonics. Techniques for reducing these losses have been

  5. Neutron and high speed photogrammetric arcjet diagnosis

    NASA Technical Reports Server (NTRS)

    Stewart, P. A. E.; Rogers, J. D.; Fowler, P. H.; Deininger, W. D.; Taylor, A. D.

    1989-01-01

    Two methods for real time internal diagnostics of arcjet engines are described. One method uses cold, thermal, or epithermal neutrons. Cold neutrons are used to detect the presence and location of hydrogenous propellants. Thermal neutrons are used to delineate the edge contours of anode and cathode surfaces and to measure stress/strain. Epithermal neutrons are used to measure temperatures on arcjet surfaces, bulk material temperatures, and point temperatures in bulk materials. It is found that this method, with an exposure time of 10 min, produces at temperature accuracy for W or Re of + or - 2.5 C. The other method uses visible-light high-speed photogrammetry to obtain images of the transient behavior of the arc during start-up and to relate this behavior to electrial supply characteristics such as voltage, current, and ripple.

  6. High Speed Photography In The United Kingdom

    NASA Astrophysics Data System (ADS)

    Lunn, George H.

    1989-06-01

    At the 13th Congress in Tokyo, I presented a paper with this title in which some early history was mentioned followed by a more detailed study of the activities of the main research groups in Britain from the period between 1950 and 1978. On this occasion, some early topics will be mentioned. The period since 1978 has seen quite a few changes in that research is now more in the hands of commercial groups as opposed to the previous governmental laboratories. It is true that the pricipal camera systems have reached towards their physical limits. However other new techniques are still expanding, for example, Lasers, Holography and Videography. The new systems are principally in the hands of major or specialist companies with the offical and industrial research groups using their products. The Association for High Speed Photography continues to encourage both researchers and users by providing oportunities for users, suppliers and manufacturers to meet and discuss.

  7. Merging of high speed argon plasma jets

    SciTech Connect

    Case, A.; Messer, S.; Brockington, S.; Wu, L.; Witherspoon, F. D.; Elton, R.

    2013-01-15

    Formation of an imploding plasma liner for the plasma liner experiment (PLX) requires individual plasma jets to merge into a quasi-spherical shell of plasma converging on the origin. Understanding dynamics of the merging process requires knowledge of the plasma phenomena involved. We present results from the study of the merging of three plasma jets in three dimensional geometry. The experiments were performed using HyperV Technologies Corp. 1 cm Minirailguns with a preionized argon plasma armature. The vacuum chamber partially reproduces the port geometry of the PLX chamber. Diagnostics include fast imaging, spectroscopy, interferometry, fast pressure probes, B-dot probes, and high speed spatially resolved photodiodes, permitting measurements of plasma density, temperature, velocity, stagnation pressure, magnetic field, and density gradients. These experimental results are compared with simulation results from the LSP 3D hybrid PIC code.

  8. Design of a high speed business transport

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The design of a High Speed Business Transport (HSBT) was considered by the Aeronautical Design Class during the academic year 1989 to 1990. The project was chosen to offer an opportunity to develop user friendliness for some computer codes such as WAVE DRAG, supplied by NASA/Langley, and to experiment with several design lessons developed by Dr. John McMasters and his colleages at Boeing. Central to these design lessons was an appeal to marketing and feasibility considerations. There was an emphasis upon simplified analytical techniques to study trades and to stimulate creative thinking before committing to extensive analytical activity. Two designs stood out among all the rest because of the depth of thought and consideration of alternatives. One design, the Aurora, used a fixed wing design to satisfy the design mission: the Viero used a swept wing configuration to overcome problems related to supersonic flight. A summary of each of these two designs is given.

  9. High speed civil transport aerodynamic optimization

    NASA Technical Reports Server (NTRS)

    Ryan, James S.

    1994-01-01

    This is a report of work in support of the Computational Aerosciences (CAS) element of the Federal HPCC program. Specifically, CFD and aerodynamic optimization are being performed on parallel computers. The long-range goal of this work is to facilitate teraflops-rate multidisciplinary optimization of aerospace vehicles. This year's work is targeted for application to the High Speed Civil Transport (HSCT), one of four CAS grand challenges identified in the HPCC FY 1995 Blue Book. This vehicle is to be a passenger aircraft, with the promise of cutting overseas flight time by more than half. To meet fuel economy, operational costs, environmental impact, noise production, and range requirements, improved design tools are required, and these tools must eventually integrate optimization, external aerodynamics, propulsion, structures, heat transfer, controls, and perhaps other disciplines. The fundamental goal of this project is to contribute to improved design tools for U.S. industry, and thus to the nation's economic competitiveness.

  10. 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.

  11. High-speed electrical motor evaluation

    SciTech Connect

    Not Available

    1989-02-03

    Under this task, MTI conducted a general review of state-of-the-art high-speed motors. The purpose of this review was to assess the operating parameters, limitations and performance of existing motor designs, and to establish commercial sources for a motor compatible with the requirements of the Brayton-cycle system. After the motor requirements were established, a list of motor types, manufacturers and designs capable of achieving the requisite performance was compiled. This list was based on an in-house evaluation of designs. Following the establishment of these options, a technical evaluation of the designs selected was conducted. In parallel with their evaluations, MTI focused on the establishment of commercial sources.

  12. HIGH SPEED KERR CELL FRAMING CAMERA

    DOEpatents

    Goss, W.C.; Gilley, L.F.

    1964-01-01

    The present invention relates to a high speed camera utilizing a Kerr cell shutter and a novel optical delay system having no moving parts. The camera can selectively photograph at least 6 frames within 9 x 10/sup -8/ seconds during any such time interval of an occurring event. The invention utilizes particularly an optical system which views and transmits 6 images of an event to a multi-channeled optical delay relay system. The delay relay system has optical paths of successively increased length in whole multiples of the first channel optical path length, into which optical paths the 6 images are transmitted. The successively delayed images are accepted from the exit of the delay relay system by an optical image focusing means, which in turn directs the images into a Kerr cell shutter disposed to intercept the image paths. A camera is disposed to simultaneously view and record the 6 images during a single exposure of the Kerr cell shutter. (AEC)

  13. High-speed digital wireless battlefield network

    NASA Astrophysics Data System (ADS)

    Dao, Son K.; Zhang, Yongguang; Shek, Eddie C.; van Buer, Darrel

    1999-07-01

    In the past two years, the Digital Wireless Battlefield Network consortium that consists of HRL Laboratories, Hughes Network Systems, Raytheon, and Stanford University has participated in the DARPA TRP program to leverage the efforts in the development of commercial digital wireless products for use in the 21st century battlefield. The consortium has developed an infrastructure and application testbed to support the digitized battlefield. The consortium has implemented and demonstrated this network system. Each member is currently utilizing many of the technology developed in this program in commercial products and offerings. These new communication hardware/software and the demonstrated networking features will benefit military systems and will be applicable to the commercial communication marketplace for high speed voice/data multimedia distribution services.

  14. Very high speed cw digital holographic interferometry

    NASA Astrophysics Data System (ADS)

    Pérez-López, Carlos; de La Torre-Ibarra, Manuel H.; Mendoza Santoyo, Fernando

    2006-10-01

    It is reported for the first time the use of a very high speed camera in digital holographic interferometry with an out of plane sensitivity setup. The image plane holograms of a spherical latex balloon illuminated by a cw laser were acquired at a rate of 4000 frames per second, representing a time spacing between holograms of 250 microseconds, for 512 × 512 pixels at 8 bits resolution. Two types of tests were accomplished for a proof of principle of the technique, one with no constrains on the object which meant random movements due to non controlled environmental air currents, and the other with specific controlled conditions on the object. Results presented correspond to a random sample of sequential digital holograms, chosen from a 1 second exposure, individually Fourier processed in order to perform the usual comparison by subtraction between consecutive pairs thus obtaining the phase map of the object out of plane displacement, shown as a movie.

  15. High speed nanotechnology-based photodetector

    NASA Astrophysics Data System (ADS)

    Kurtz, Russell M.; Pradhan, Ranjit D.; Parfenov, Alexander V.; Holmstedt, Jason; Esterkin, Vladimir; Menon, Naresh; Aye, Tin M.; Chua, Kang-Bin; Schindler, Axel; Balandin, Alexander A.; Nichter, James E.

    2005-08-01

    An inexpensive, easily integrated, 40 Gbps photoreceiver operating in the communications band would revolutionize the telecommunications industry. While generation of 40 Gbps data is not difficult, its reception and decoding require specific technologies. We present a 40 Gbps photoreceiver that exceeds the capabilities of current devices. This photoreceiver is based on a technology we call "nanodust." This new technology enables nanoscale photodetectors to be embedded in matrices made from a different semiconductor, or directly integrated into a CMOS amplification circuit. Photoreceivers based on quantum dust technology can be designed to operate in any spectral region, including the telecommunications bands near 1.31 and 1.55 micrometers. This technology also lends itself to normal-incidence detection, enabling a large detector size with its associated increase in sensitivity, even at high speeds and reception wavelengths beyond the capability of silicon.

  16. Safety of high speed guided ground transportation systems: Magnetic and electric field testing of the Massachusetts Bay Transportation Authority (MBTA) urban transit system. Volume 2. Appendices. Final report, September 1992-March 1993

    SciTech Connect

    Jacobs, W.L.; Robertson, D.C.; Steiner, G.A.

    1993-06-01

    The safety of magnetically levitated (maglev) and high speed rail (HSR) trains proposed for application in the United States is the responsibility of the Federal Railroad Administration (FRA). Plans for near future US applications include maglev projects (e.g. in Orlando, FL and Pittsburgh, PA) and high speed rail (the French Train a Grande Vitesse (TGV) in the Texas Triangle). The report provides the Analysis (Vol. I) of results, and detailed data and statistical summaries (Vol. II, Appendices) of representative EMF profiles on vehicles and facilities typical of electrotechnologies used in the transit system (3rd rail dc, catenary with pantograph, trolley bus). Each electrotechnology has specific EMF frequency signatures. EMF data represent a range of system operating conditions and locations (in vehicles, stations and waysides), as well as traffic control and electrical power supply facilities.

  17. Photodetector having high speed and sensitivity

    DOEpatents

    Morse, Jeffrey D.; Mariella, Jr., Raymond P.

    1991-01-01

    The present invention provides a photodetector having an advantageous combination of sensitivity and speed; it has a high sensitivity while retaining high speed. In a preferred embodiment, visible light is detected, but in some embodiments, x-rays can be detected, and in other embodiments infrared can be detected. The present invention comprises a photodetector having an active layer, and a recombination layer. The active layer has a surface exposed to light to be detected, and comprises a semiconductor, having a bandgap graded so that carriers formed due to interaction of the active layer with the incident radiation tend to be swept away from the exposed surface. The graded semiconductor material in the active layer preferably comprises Al.sub.1-x Ga.sub.x As. An additional sub-layer of graded In.sub.1-y Ga.sub.y As may be included between the Al.sub.1-x Ga.sub.x As layer and the recombination layer. The recombination layer comprises a semiconductor material having a short recombination time such as a defective GaAs layer grown in a low temperature process. The recombination layer is positioned adjacent to the active layer so that carriers from the active layer tend to be swept into the recombination layer. In an embodiment, the photodetector may comprise one or more additional layers stacked below the active and recombination layers. These additional layers may include another active layer and another recombination layer to absorb radiation not absorbed while passing through the first layers. A photodetector having a stacked configuration may have enhanced sensitivity and responsiveness at selected wavelengths such as infrared.

  18. Computation of high-speed reacting flows

    NASA Astrophysics Data System (ADS)

    Clutter, James Keith

    A computational study has been conducted for high-speed reacting flows relevant to munition problems, including shock-induced combustion and gun muzzle blast. The theoretical model considers inviscid and viscous flows, multi-species, finite rate chemical reaction schemes, and turbulence. Both the physical and numerical aspects are investigated to determine their impact on simulation accuracy. A range of hydrogen and oxygen reaction mechanisms are evaluated for the shock-induced combustion flow scenario. Characteristics of the mechanisms such as the induction time, heat release rate, and second explosion limit are found to impact the accuracy of the computation. On the numerical side, reaction source term treatments, including logarithmic weighting and scaling modifications, are investigated to determine their effectiveness in addressing numerical errors caused by disparate length scales between chemical reactions and fluid dynamics. It is demonstrated that these techniques can enhance solution accuracy. Computations of shock-induced combustion have also been performed using a κ-ɛ model to account for the turbulent transport of species and heat. An algebraic model of the temperature fluctuations has been used to estimate the impact of the turbulent effect on the chemical reaction source terms. The turbulence effects when represented with the current models are found to be minimal in the shock-induced combustion flow investigated in the present work. For the gun system simulations, computations for both a large caliber howitzer and small caliber firearms are carried out. A reduced kinetic scheme and an algebraic turbulence model are employed. The present approach, which accounts for the chemical reaction aspects of the gun muzzle blast problem, is found to improve the prediction of peak overpressures and can capture the effects produced by small caliber firearm sound suppressors. The present study has established the numerical and physical requirements for

  19. Photogrammetric Techniques Using High-Speed Cineradiography

    NASA Astrophysics Data System (ADS)

    Nusholtz, Guy S.; Bender, Max; Suggitt, Bryan R.; Kaiker, Patricia S.; Muscott, Gail J.

    1986-01-01

    A high-speed 16-mm cineradiographic system previously developed at the University of Michigan Transportation Research Institute for use in biomechanics research has been undergoing a continuous upgrading in capability. In addition to changes in the structural aspect of the cineradiography, improvements have been made in the procedures used to obtain better image quality as well as methods for interpretation of the digitized results. The current improvements in the system include: 1) filtering the X-ray source before penetration of the subject to increase image contrast as well as to protect the image tube; 2) pre-processing of the film to increase its effective speed; 3) development of a neutral density radio-contrast media for outlining anatomical structure without using the vascular system; and 4) development of procedures for obtaining analytical information about motion of non-rigid anatomical structures from digitized film. This system now consists of either a 35-mm Photosonics 4B, a 16-mm Photosonics 1B, or a 16-mm Milliken which views a 50-mm (2-inch) diameter output of a P-11 phosphor of a high gain, four-stage magnetically focused image intensifier tube, gated on and off synchronously with the motion picture camera shutter. A lens optically couples the input photocathode of the image tube to an X-ray fluorescent (rare earth) screen image produced by a smoothed DC X-ray generator of a conventional type. The system is capable of looking at a large spectrum of anatomical structures under a wide range of dynamic loading conditions.

  20. High-speed shutter for mirror cameras

    NASA Astrophysics Data System (ADS)

    Trofimenko, Vladimir V.; Klimashin, V. P.; Drozhbin, Yu. A.

    1999-06-01

    High-speed mirror cameras are mainly used for investigations of quick processes in a wide spectral range of radiation including ultraviolet and infrared regions (from 0.2 to 11 micrometer). High-speed shutters for these cameras must be non-selective and when opened must transmit the whole radiation without refraction, absorption and scattering. Electromechanical, electrodynamic and induction-dynamic shutters possess such properties because their optical channels contain no medium. Electromechanical shutters are devices where the displacement of the working blind which opens or closes an aperture is produced by a spring. Such shutters are relatively slow and are capable of closing an aperture of 50 mm in diameter in 10 - 15 ms. Electrodynamic and induction-dynamic shutters are devices where displacement of a blind is produced by the electromagnetic interaction between circuits with electric currents. In induction-dynamic shutter the secondary circuit is current-conducting blind itself in which a short-circuited loop forms. The latter is more quick because of the lower mass of its moveable secondary circuit. For this reason induction-dynamic shutters with a flat primary circuit coil and a tightly fitted to it load- bearing aluminum plate have been investigated. The blind which opens or closes an aperture was attached to this plate. The dependencies of cut-off time on the form, size and the number of turns of the primary circuit coil, on size, type of material, thickness and weight of the load-bearing plate and the blind, as well as on capacitance in the discharge circuit and the capacitor voltage have been investigated. The influence of the environmental atmosphere on the cut-off time was also studied. For this purpose the shutter was placed into the chamber where vacuum up to 10- atm could be produced. As a result the values of the above mentioned parameters have been optimized and the designs of the shutters which are shown have been developed.

  1. High Speed/ Low Effluent Process for Ethanol

    SciTech Connect

    M. Clark Dale

    2006-10-30

    n this project, BPI demonstrated a new ethanol fermentation technology, termed the High Speed/ Low Effluent (HS/LE) process on both lab and large pilot scale as it would apply to wet mill and/or dry mill corn ethanol production. The HS/LE process allows very rapid fermentations, with 18 to 22% sugar syrups converted to 9 to 11% ethanol ‘beers’ in 6 to 12 hours using either a ‘consecutive batch’ or ‘continuous cascade’ implementation. This represents a 5 to 8X increase in fermentation speeds over conventional 72 hour batch fermentations which are the norm in the fuel ethanol industry today. The ‘consecutive batch’ technology was demonstrated on a large pilot scale (4,800 L) in a dry mill corn ethanol plant near Cedar Rapids, IA (Xethanol Biofuels). The pilot demonstrated that 12 hour fermentations can be accomplished on an industrial scale in a non-sterile industrial environment. Other objectives met in this project included development of a Low Energy (LE) Distillation process which reduces the energy requirements for distillation from about 14,000 BTU/gal steam ($0.126/gal with natural gas @ $9.00 MCF) to as low as 0.40 KW/gal electrical requirements ($0.022/gal with electricity @ $0.055/KWH). BPI also worked on the development of processes that would allow application of the HS/LE fermentation process to dry mill ethanol plants. A High-Value Corn ethanol plant concept was developed to produce 1) corn germ/oil, 2) corn bran, 3) ethanol, 4) zein protein, and 5) nutritional protein, giving multiple higher value products from the incoming corn stream.

  2. Modeling the rail surface unevenness of a high-precision radio telescope

    NASA Astrophysics Data System (ADS)

    Li, Na; Li, Peng; Wu, Jiang; Duan, Bao-Yan

    2017-02-01

    This study proposed a coarse-fine mixed model for describing the rail surface unevenness of an ultra-large fully steerable radio telescope (Qi Tai Telescope) with a diameter of 110 meters. The rail surface unevenness includes information on error arising from two different scales, i.e., the long-period-short-change and the short-period-long-change. Consequently, in this study an idea of a mixed model was proposed, in which trigonometric and fractal functions were, respectively, used to describe information on error from two scales. Key parameters were determined by using the least squares method and the wavelet transform method, and finally, a specific mathematical expression of the model was obtained by optimization. To validate the effectiveness of the new modeling method, the mixed model was then used to describe the rails of the Green Bank Telescope, the Large Millimeter Telescope, and a radio telescope in Miyun, Beijing. A comparative study revealed that the maximum error was less than 15%, thus the result was superior to those of existing modeling methods.

  3. Modeling, control design, and performance evaluation of high speed ground vehicle dynamics

    SciTech Connect

    Faye, I.; Kortum, W.; Schwartz, W. )

    1989-01-01

    The interest in developing high speed ground transportation systems is one reason for directing attention to the modeling and simulation of the dynamic behavior of vehicle systems. Rail-guided vehicles; i.e., conventional railways, advanced railway systems, or magnetically levitated trains, represent the practical implementation of such ground transportation systems. One computer program that is well suited for the analysis of rail-guided vehicles is the multibody program MEDYNA. This paper demonstrates the application of MEDYNA for control law design and to performance evaluation of such advanced vehicles. A brief description is made of the modeling requirements of magnetically levitated systems, along with a summary of some of the related capabilities and computational methods of MEDNYA. As a case study, analysis of a vehicle based on the German Transrapid system is presented. System matrices of a simplified vehicle model are established and control design is performed with the aid of MATLAB. Performance evaluation is studied with a complex model of the Transrapid vehicle and elastic guideways.

  4. 8-Foot High Speed Tunnel (HST

    NASA Technical Reports Server (NTRS)

    1957-01-01

    Interior view of the slotted throat test section installed in the 8-Foot High Speed Tunnel (HST) in 1950. The slotted region is about 160 inches in length. In this photograph, the sting-type model support is seen straight on. In a NASA report, the test section is described as follows: 'The test section of the Langley 8-foot transonic tunnel is dodecagonal in cross section and has a cross-sectional area of about 43 square feet. Longitudinal slots are located between each of the 12 wall panels to allow continuous operation through the transonic speed range. The slots contain about 11 percent of the total periphery of the test section. Six of the twelve panels have windows in them to allow for schlieren observations. The entire test section is enclosed in a hemispherical shaped chamber.' John Becker noted that the tunnel's 'final achievement was the development and use in routine operations of the first transonic slotted throat. The investigations of wing-body shapes in this tunnel led to Whitcomb's discovery of the transonic area rule.' James Hansen described the origins of the the slotted throat as follows: 'In 1946 Langley physicist Ray H. Wright conceived a way to do transonic research effectively in a wind tunnel by placing slots in the throat of the test section. The concept for what became known as the slotted-throat or slotted-wall tunnel came to Wright not as a solution to the chronic transonic problem, but as a way to get rid of wall interference (i.e., the mutual effect of two or more meeting waves or vibrations of any kind caused by solid boundaries) at subsonic speeds. For most of the year before Wright came up with this idea, he had been trying to develop a theoretical understanding of wall interference in the 8-Foot HST, which was then being repowered for Mach 1 capability.' When Wright presented these ideas to John Stack, the response was enthusiastic but neither Wright nor Stack thought of slotted-throats as a solution to the transonic problem, only

  5. Circuity analyses of HSR network and high-speed train paths in China

    PubMed Central

    Zhao, Shuo; Huang, Jie; Shan, Xinghua

    2017-01-01

    Circuity, defined as the ratio of the shortest network distance to the Euclidean distance between one origin–destination (O-D) pair, can be adopted as a helpful evaluation method of indirect degrees of train paths. In this paper, the maximum circuity of the paths of operated trains is set to be the threshold value of the circuity of high-speed train paths. For the shortest paths of any node pairs, if their circuity is not higher than the threshold value, the paths can be regarded as the reasonable paths. With the consideration of a certain relative or absolute error, we cluster the reasonable paths on the basis of their inclusion relationship and the center path of each class represents a passenger transit corridor. We take the high-speed rail (HSR) network in China at the end of 2014 as an example, and obtain 51 passenger transit corridors, which are alternative sets of train paths. Furthermore, we analyze the circuity distribution of paths of all node pairs in the network. We find that the high circuity of train paths can be decreased with the construction of a high-speed railway line, which indicates that the structure of the HSR network in China tends to be more complete and the HSR network can make the Chinese railway network more efficient. PMID:28945757

  6. Circuity analyses of HSR network and high-speed train paths in China.

    PubMed

    Hu, Xinlei; Zhao, Shuo; Shi, Feng; Huang, Jie; Shan, Xinghua

    2017-01-01

    Circuity, defined as the ratio of the shortest network distance to the Euclidean distance between one origin-destination (O-D) pair, can be adopted as a helpful evaluation method of indirect degrees of train paths. In this paper, the maximum circuity of the paths of operated trains is set to be the threshold value of the circuity of high-speed train paths. For the shortest paths of any node pairs, if their circuity is not higher than the threshold value, the paths can be regarded as the reasonable paths. With the consideration of a certain relative or absolute error, we cluster the reasonable paths on the basis of their inclusion relationship and the center path of each class represents a passenger transit corridor. We take the high-speed rail (HSR) network in China at the end of 2014 as an example, and obtain 51 passenger transit corridors, which are alternative sets of train paths. Furthermore, we analyze the circuity distribution of paths of all node pairs in the network. We find that the high circuity of train paths can be decreased with the construction of a high-speed railway line, which indicates that the structure of the HSR network in China tends to be more complete and the HSR network can make the Chinese railway network more efficient.

  7. High speed image correlation for vibration analysis

    NASA Astrophysics Data System (ADS)

    Siebert, T.; Wood, R.; Splitthof, K.

    2009-08-01

    Digital speckle correlation techniques have already been successfully proven to be an accurate displacement analysis tool for a wide range of applications. With the use of two cameras, three dimensional measurements of contours and displacements can be carried out. With a simple setup it opens a wide range of applications. Rapid new developments in the field of digital imaging and computer technology opens further applications for these measurement methods to high speed deformation and strain analysis, e.g. in the fields of material testing, fracture mechanics, advanced materials and component testing. The high resolution of the deformation measurements in space and time opens a wide range of applications for vibration analysis of objects. Since the system determines the absolute position and displacements of the object in space, it is capable of measuring high amplitudes and even objects with rigid body movements. The absolute resolution depends on the field of view and is scalable. Calibration of the optical setup is a crucial point which will be discussed in detail. Examples of the analysis of harmonic vibration and transient events from material research and industrial applications are presented. The results show typical features of the system.

  8. Safety of high speed guided ground transportation systems: Magnetic and electric field testing of the Washington Metropolitan Area transit authority metrorail system. Volume 1. Analysis. Final report, September 1992-March 1993

    SciTech Connect

    Dietrich, F.M.; Papas, P.N.; Jacobs, W.L.; Ferro, W.E.

    1993-06-01

    The safety of magnetically levitated (maglev) and high speed rail (HSR) trains proposed for application in the United States is the responsibility of the Federal Railroad Administration (FRA). Plans for near future US applications include maglev technology (e.g. in Orlando, FL and Pittsburgh, PA) and high speed rail (e.g. the French Train a Grande Vitesse (TGV) in the Texas Triangle, between Dallas-Fort Worth, Houston and San Antonio, and along five designated high speed corridors). Concerns exist regarding the potential safety, environmental and health effects on the public and on transportation workers due to electrification along new or existing rail corridors, and to maglev and high speed rail operations. Therefore, the characterization of electric and magnetic fields (EMF) produced by both steady (dc) and alternating currents (ac) at power frequency (50 Hz in Europe and 60 Hz in the U.S.) and above, in the Extreme Low Frequency (ELF) range (3-3000 Hz) is of interest. An EMF survey of the Washington Metrorail (WMATA) transit system was performed, as part of a comprehensive comparative EMF safety assessment of the German Transrapid (TR-07) maglev system with other existing and advanced rail systems. The report provides the Analysis (Vol. I) of results, and detailed data and statistical summaries (Vol. II, Appendices) of representative EMF profiles on vehicles and facilities typical of this transit electrotechnology (third rail dc). EMF data represent a range of train operating conditions and locations (in vehicles, stations and waysides), as well as in traffic control and electrical power supply facilities.

  9. Light rail: where the action is

    SciTech Connect

    Kizzia, T.; Middleton, W.D.

    1980-09-29

    Light rail transit provides the operating benefits of fixed guideway transportation without the high capital cost of heavy rapid transit. The basic light rail concept can be modified to meet a particular city's circumstances. Light rail projects in Pittsburgh, Buffalo, Portland, and San Diego are examined. The status of the light rail proposal for the Denver area is discussed. Denver's Regional Transportation District recently demonstrated that a 73 mi at-grade light rail network would satisfy Denver's need for more cost-effective, less polluting transportation. Various light rail vehicles are described. Advantages and limitations, possible variations, and significant advancements in light rail vehicle technology are discussed. (1 drawing, 1 map, 12 photos)

  10. 14 CFR 23.253 - High speed characteristics.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false High speed characteristics. 23.253 Section 23.253 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established...

  11. 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.

  12. High speed exhaust gas recirculation valve

    SciTech Connect

    Fensom, Rod; Kidder, David J.

    2005-01-18

    In order to minimize pollutants such as Nox, internal combustion engines typically include an exhaust gas recirculation (EGR) valve that can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled. It is desirable to have an EGR valve with fast-acting capabilities, and it is also desirable to have the EGR valve take up as little space as possible. An exhaust gas recirculation valve is provided that includes an exhaust passage tube, a valve element pivotally mounted within the exhaust passage tube, a linear actuator; and a gear train. The gear train includes a rack gear operatively connected to the linear actuator, and at least one rotatable gear meshing with the rack gear and operatively connected to the valve element to cause rotation of the valve element upon actuation of the linear actuator. The apparatus provides a highly compact package having a high-speed valve actuation capability.

  13. Material constraints on high-speed design

    NASA Astrophysics Data System (ADS)

    Bucur, Diana; Militaru, Nicolae

    2015-02-01

    Current high-speed circuit designs with signal rates up to 100Gbps and above are implying constraints for dielectric and conductive materials and their dependence of frequency, for component elements and for production processes. The purpose of this paper is to highlight through various simulation results the frequency dependence of specific parameters like insertion and return loss, eye diagrams, group delay that are part of signal integrity analyses type. In low-power environment designs become more complex as the operation frequency increases. The need for new materials with spatial uniformity for dielectric constant is a need for higher data rates circuits. The fiber weave effect (FWE) will be analyzed through the eye diagram results for various dielectric materials in a differential signaling scheme given the fact that the FWE is a phenomenon that affects randomly the performance of the circuit on balanced/differential transmission lines which are typically characterized through the above mentioned approaches. Crosstalk between traces is also of concern due to propagated signals that have tight rise and fall times or due to high density of the boards. Criteria should be considered to achieve maximum performance of the designed system requiring critical electronic properties.

  14. High-Speed Data Recorder for Space, Geodesy, and Other High-Speed Recording Applications

    NASA Technical Reports Server (NTRS)

    Taveniku, Mikael

    2013-01-01

    A high-speed data recorder and replay equipment has been developed for reliable high-data-rate recording to disk media. It solves problems with slow or faulty disks, multiple disk insertions, high-altitude operation, reliable performance using COTS hardware, and long-term maintenance and upgrade path challenges. The current generation data recor - ders used within the VLBI community are aging, special-purpose machines that are both slow (do not meet today's requirements) and are very expensive to maintain and operate. Furthermore, they are not easily upgraded to take advantage of commercial technology development, and are not scalable to multiple 10s of Gbit/s data rates required by new applications. The innovation provides a softwaredefined, high-speed data recorder that is scalable with technology advances in the commercial space. It maximally utilizes current technologies without being locked to a particular hardware platform. The innovation also provides a cost-effective way of streaming large amounts of data from sensors to disk, enabling many applications to store raw sensor data and perform post and signal processing offline. This recording system will be applicable to many applications needing realworld, high-speed data collection, including electronic warfare, softwaredefined radar, signal history storage of multispectral sensors, development of autonomous vehicles, and more.

  15. 75 FR 38365 - High-Speed Intercity Passenger Rail (HSIPR) Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... basis. While there are no predetermined minimum or maximum dollar thresholds for awards, FRA anticipates...: Eligibility Information Applications under this solicitation will be required to meet minimum requirements... requirements. To the extent that an application's substance exceeds the minimum eligibility requirements...

  16. 75 FR 16564 - High-Speed Intercity Passenger Rail (HSIPR) Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-01

    ... predetermined minimum or maximum dollar thresholds for awards, FRA anticipates making multiple awards from the... activities will be required to meet minimum requirements related to applicant eligibility, project... the minimum eligibility requirements described below, such qualifications will be considered in...

  17. 76 FR 14443 - High-Speed Intercity Passenger Rail (HSIPR) Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    ... reimbursable basis. While there are no predetermined minimum or maximum dollar thresholds for awards, FRA...: Eligibility Information Applications under this solicitation will be required to meet minimum requirements... requirements. To the extent that an application's substance exceeds the minimum eligibility requirements...

  18. Airports, Highways, High-Speed Rail, Trains, and Transit: Make it in America Act

    THOMAS, 112th Congress

    Rep. Garamendi, John [D-CA-10

    2011-02-10

    House - 02/11/2011 Referred to the Subcommittee on Railroads, Pipelines, and Hazardous Materials. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  19. Texas Should Require Homeland Security Standards for High-Speed Rail

    DTIC Science & Technology

    2015-12-01

    suggests that this writing is the first in its specific application. This thesis places the project in historical and geographical context and reviews...In addition, it suggests that this writing is the first in its specific application. This thesis places the project in historical and geographical...examples appear later in this thesis. This writing was prepared using publicly available information. None of the materials used were classified

  20. 75 FR 16552 - High-Speed Intercity Passenger Rail (HSIPR) Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-01

    ... Executive Order 12893, Principles for Federal Infrastructure Investments, 59 FR 4233, to base infrastructure... agreed upon investment. The substantial Federal involvement for these projects will include technical... infrastructure-owning railroads and the railroad that operates or will operate the benefiting...

  1. High speed imaging technology: yesterday, today, and tomorrow

    NASA Astrophysics Data System (ADS)

    Pendley, Gil J.

    2003-07-01

    The purpose of this discussion is to familiarize readers with an overview of high-speed imaging technology as a means of analyzing objects in motion that occur too fast for the eye to see or conventional photography or video to capture. This information is intended to provide a brief historical narrative from the inception of high-speed imaging in the USA and the acceptance of digital video technology to augment or replace high-speed motion picture cameras. It is not intended a definitive work on the subject. For those interested in greater detail, such as application techniques, formulae, very high-speed and ultra speed technology etc. I recommend the latest text on the subject: High Speed Photography and Photonics first published in 1997 by Focal Press in the UK and copyrighted by the Association for High Speed Photography in the United Kingdom.

  2. Analysis of coupling between high-speed railway and common speed railway system in transportation corridor

    NASA Astrophysics Data System (ADS)

    Zhou, Hongchang; Li, Haijun; Chen, Xiaohong; Zhu, Changfeng

    2017-04-01

    The high-speed railway and common speed railway subsystems as important components of the railway transportation system, can make railway traffic organization more orderly, when there are a rational division and balance development between them. In order to quantitatively evaluate the coordinate relations between high-speed railway subsystem and common speed railway subsystem, this paper takes the railway transportation corridor from Baoji to Lanzhou as an example. Firstly, using Logit model and grey forecasting model predict the passenger volume, passenger turnover and time value of high-speed railway and common speed railway in the Baoji-Lanzhou corridor. And then, the coupling forecast model of these two subsystems is established. Lastly, the coupling and coupling coordination of these two subsystems using are predicted and analyzed at theatrically level.

  3. The unstable behavior of low and high-speed compressors

    SciTech Connect

    Day, I.J. . Whittle Lab.); Freeman, C. )

    1994-04-01

    By far the greater part of the understanding about stall and surge in axial compressors comes from work on low-speed laboratory machines. As a general rule, these machines do not model the compressibility effects present in high-speed compressors and therefore doubt has always existed about the application of low-speed results to high-speed machines. In recent years interest in active control has led to a number of studies of compressor stability in engine-type compressors. The instrumentation used in these experiments has been sufficiently detailed that, for the first time, adequate data are available to make direct comparisons between high-speed and low-speed compressors. This paper presents new data from an eight-stage fixed geometry engine compressor and compares then with low-speed laboratory data. The results show remarkable similarities in both the stalling and surging behavior of the two machines, particularly when the engine compressor is run at intermediate speeds. The engine results also show that, as in the laboratory tests, surge is precipitated by the onset of rotating stall. This is true even at very high speeds where it had previously been thought that surge might be the result of a blast wave moving through the compressor. This paper therefore contains new information about high-speed compressors and confirms that low-speed testing is an effective means of obtaining insight into the behavior of high-speed machines.

  4. Safety of high speed guided ground transportation systems: Comparison of magnetic and electric fields of conventional and advanced electrified transportation systems. Final report, September 1992-March 1993

    SciTech Connect

    Dietrich, F.M.; Feero, W.E.; Jacobs, W.L.

    1993-08-01

    Concerns exist regarding the potential safety, environmental and health effects on the public and on transportation workers due to electrification along new or existing rail corridors, and to proposed maglev and high speed rail operations. Therefore, the characterization of electric and magnetic fields (EMF) produced by both steady (dc) and alternating currents (ac) at power frequency (50 Hz in Europe and 60 Hz in the U.S.) and above, in the Extreme Low Frequency (ELF) range (3-3000 Hz) is of interest. The report summarizes and compares the results of a survey of EMF characteristics (spatial, temporal and frequency bands) for representative conventional railroad and transit and advanced high-speed systems including: the German TR-07 maglev system; the Amtrak Northeast Corridor (NEC) and North Jersey Transit (NJT) trains; the Washington, DC Metrorail (WMATA) and the Boston, MA (MBTA) transit systems; and the French TGV-A high speed rail system. This comprehensive comparative EMF survey produced both detailed data and statistical summaries of EMF profiles, and their variability in time and space. EMF ELF levels for WMATA are also compared to those produced by common environmental sources at home, work, and under power lines, but have specific frequency signatures.

  5. Review on the Traction System Sensor Technology of a Rail Transit Train.

    PubMed

    Feng, Jianghua; Xu, Junfeng; Liao, Wu; Liu, Yong

    2017-06-11

    The development of high-speed intelligent rail transit has increased the number of sensors applied on trains. These play an important role in train state control and monitoring. These sensors generally work in a severe environment, so the key problem for sensor data acquisition is to ensure data accuracy and reliability. In this paper, we follow the sequence of sensor signal flow, present sensor signal sensing technology, sensor data acquisition, and processing technology, as well as sensor fault diagnosis technology based on the voltage, current, speed, and temperature sensors which are commonly used in train traction systems. Finally, intelligent sensors and future research directions of rail transit train sensors are discussed.

  6. Safety of high speed ground transportation systems: Analytical methodology for safety validation of computer controlled subsystems. Volume 2. Development of a safety validation methodology. Final report

    SciTech Connect

    Luedeke, J.F.

    1995-09-01

    The evolution in the implementations of safety critical systems in the railroad industry from simple vital relays to more complex computer-based configurations has raised many issues among users as well as the Federal Railraod Authority (FRA). Foremost among these issues is the need to assure similar or improved levels of safety those currently provided by conventional fail-safe technology. This concern is heightened in newer high-speed rail and maglev systems which operate or are being designed to operate at considerably higher speeds and levels of automation than conventional rail systems. The overall objective of this program was to develop a safety validation methodology that could be considered (by the FRA) for use as a standard for manufacturers and users to help ensure the safe operation of safety critical computer-based system.

  7. The high speed civil transport and NASA's High Speed Research (HSR) program

    NASA Technical Reports Server (NTRS)

    Shaw, Robert J.

    1994-01-01

    Ongoing studies being conducted not only in this country but in Europe and Asia suggest that a second generation supersonic transport, or High-Speed Civil Transport (HSCT), could become an important part of the 21st century international air transportation system. However, major environmental compatibility and economic viability issues must be resolved if the HSCT is to become a reality. This talk will overview the NASA High-Speed Research (HSR) program which is aimed at providing the U.S. industry with a technology base to allow them to consider launching an HSCT program early in the next century. The talk will also discuss some of the comparable activities going on within Europe and Japan.

  8. How to Combine Engines to Achieve High Speed, Hypersonic Speed, Speed of Light and Even Higher-Applications

    NASA Astrophysics Data System (ADS)

    Mwizerwa, Celestin; Nishimwe, Celestine

    2014-03-01

    When Einstein left us, he left us a really big problem to solve, does anything can travel faster than the speed of light? There hasn't been any way to try this in the past, because there were any technology which could accelerate objects at this speed. What researchers tried to do, was to accelerate particles. But there must be a way to play with speeds so that, as we do math, we may practically multiply the speed by any number we want, we also may practically divide the speed by any number we want. In this paper I will try to show how. Also, In our real life, there might be a need of such high speeds, so that a lot of problems may be solved, as for example the airplane technology, electric power, space travel, car transmission, industrial high temperature and so on ...I do not say for sure that, the object will move faster than the speed of light, but, people who have ability may try to accelerate it at this speed and even faster to see what will happen as now it is very easy to realize. There are two ways; you go to space to do it or, you create a vacuum and move it inside.

  9. High speed point derivative microseismic detector

    DOEpatents

    Uhl, James Eugene; Warpinski, Norman Raymond; Whetten, Ernest Blayne

    1998-01-01

    A high speed microseismic event detector constructed in accordance with the present invention uses a point derivative comb to quickly and accurately detect microseismic events. Compressional and shear waves impinging upon microseismic receiver stations disposed to collect waves are converted into digital data and analyzed using a point derivative comb including assurance of quiet periods prior to declaration of microseismic events. If a sufficient number of quiet periods have passed, the square of a two point derivative of the incoming digital signal is compared to a trip level threshold exceeding the determined noise level to declare a valid trial event. The squaring of the derivative emphasizes the differences between noise and signal, and the valid event is preferably declared when the trip threshold has been exceeded over a temporal comb width to realize a comb over a given time period. Once a trial event has been declared, the event is verified through a spatial comb, which applies the temporal event comb to additional stations. The detector according to the present invention quickly and accurately detects initial compressional waves indicative of a microseismic event which typically exceed the ambient cultural noise level by a small amount, and distinguishes the waves from subsequent larger amplitude shear waves.

  10. High speed point derivative microseismic detector

    DOEpatents

    Uhl, J.E.; Warpinski, N.R.; Whetten, E.B.

    1998-06-30

    A high speed microseismic event detector constructed in accordance with the present invention uses a point derivative comb to quickly and accurately detect microseismic events. Compressional and shear waves impinging upon microseismic receiver stations disposed to collect waves are converted into digital data and analyzed using a point derivative comb including assurance of quiet periods prior to declaration of microseismic events. If a sufficient number of quiet periods have passed, the square of a two point derivative of the incoming digital signal is compared to a trip level threshold exceeding the determined noise level to declare a valid trial event. The squaring of the derivative emphasizes the differences between noise and signal, and the valid event is preferably declared when the trip threshold has been exceeded over a temporal comb width to realize a comb over a given time period. Once a trial event has been declared, the event is verified through a spatial comb, which applies the temporal event comb to additional stations. The detector according to the present invention quickly and accurately detects initial compressional waves indicative of a microseismic event which typically exceed the ambient cultural noise level by a small amount, and distinguishes the waves from subsequent larger amplitude shear waves. 9 figs.

  11. Computation of High Speed Jet Noise

    NASA Technical Reports Server (NTRS)

    Freund, Jonathan B.

    2002-01-01

    The objective of this work was to use direct numerical simulation (DNS) techniques to study the physics of noise generation by a high-speed turbulent jet. A Mach 0.9, Reynolds number 3,600 jet was selected because of available experimental data. New numerical methods for generating disturbances at the nozzle and computing far-field sound were developed and reported in the course of this work. Over 25 million mesh points were used in the simulations which ran for over 50,000 timesteps and required over 50,000 processor hours on state-of-the-art parallel computer systems to complete. Figures show a visualization of the jet and sound field, a comparison of the mean flow development with the experiment, a directivity comparison with the experiment, and time spectrum comparison with the experiment. Agreement is seen to be excellent. These are fully document in the attached references. Full details of the work, detailed achievements and conclusions are discussed in appendices, which are copies of publications that resulted from this work. We have studied noise mechanisms in supersonic jets, the refraction of sound by turbulence in subsonic jets, and noise sources in conjunction with a DNS of a Mach 0.9 jet.

  12. 8-Foot High Speed Tunnel (HST)

    NASA Technical Reports Server (NTRS)

    1953-01-01

    Semi-automatic readout equipment installed in the 1950s used for data recording and reduction in the 8-Foot High Speed Tunnel (HST). A 1957 NACA report on wind tunnel facilities at Langley included these comments on the data recording and reduction equipment for the 8-foot HST: 'The data recording and reduction equipment used for handling steady force and pressure information at the Langley 8-foot transonic tunnel is similar to that described for the Langley 16-foot transonic tunnel. Very little dynamic data recording equipment, however, is available.' The description of the 16-foot transonic tunnel equipment is as follows: 'A semiautomatic force data readout system provides tabulated raw data and punch card storage of raw data concurrent with the operation of the wind tunnel. Provision is made for 12 automatic channels of strain gage-data output, and eight channels of four-digit manually operated inputs are available for tabulating and punching constants, configuration codes, and other information necessary for data reduction and identification. The data are then processed on electronic computing machines to obtain the desired coefficients. These coefficients and their proper identification are then machine tabulated to provide a printed record of the results. The punched cards may also be fed into an automatic plotting device for the preparation of plots necessary for data analysis.'

  13. High-transonic-speed transport aircraft study

    NASA Technical Reports Server (NTRS)

    Kulfan, R. M.

    1974-01-01

    An initial design study of high-transonic-speed transport aircraft has been completed. Five different design concepts were developed. These included fixed swept wing, variable-sweep wing, delta wing, double-fuselage yawed-wing, and single-fuselage yawed-wing aircraft. The boomless supersonic design objectives of range = 5560 km (3000 nmi), payload = 18,143 kg (40,000 lb), Mach = 1.2, and FAR Part 36 aircraft noise levels were achieved by the single-fuselage yawed-wing configuration with a gross weight of 211,828 kg (467,000 lb). A noise level of 15 EPNdB below FAR Part 36 requirements was obtained with a gross weight increase to 226,796 kg (500,000 lb). The off-design subsonic range capability for this configuration exceeded the Mach 1.2 design range by more than 20%. Although wing aeroelastic divergence was a primary design consideration for the yawed-wing concepts, the graphite-epoxy wings of this study were designed by critical gust and maneuver loads rather than by divergence requirements. The transonic nacelle drag is shown to be very sensitive to the nacelle installation. A six-degree-of-freedom dynamic stability analysis indicated that the control coordination and stability augmentation system would require more development than for a symmetrical airplane but is entirely feasible. A three-plane development plan is recommended to establish the full potential of the yawed-wing concept.

  14. High speed imaging in icing windtunnel tests

    NASA Astrophysics Data System (ADS)

    de Pauw, Dennis; Graham, Percival; Dolatabadi, Ali

    2012-11-01

    The detailed visualization and behavior of a spray impinging on a hydrophilic, and superhydrophobic aerodynamic shape in isothermal room and icing conditions can provide deep understanding of in-flight icing. A superhydrophobic coating has a very low surface energy so it can be used to counteract the ice accumulation. It also reduces the adhesion strength of ice to the surface which ensures easier removal of the ice during flight. The focus of the experiments primarily lies on the fundamental study of multiple droplet, i.e. spray, impact on a NACA 0012 airfoil in room and icing conditions. Under such conditions, important icing features such as rivulets and runback flow are observed. This provides us with the basics of ice formation on an aerodynamic surface. The study also focuses on the comparison between aluminum and superhydrophobic surfaces for ice accumulation in conditions which approach flight conditions. All the experiments are carried out in a small scale icing windtunnel using high speed photography with frame rates ranging from five thousand to fifty thousand frames per second.

  15. Flickering aurora studies using high speed cameras

    NASA Astrophysics Data System (ADS)

    McHarg, M. G.; Stenbaek-Nielsen, H. C.; Samara, M.; Michell, R.; Hampton, D. L.; Haaland, R. K.

    2009-12-01

    We report on observations of flickering aurora using two different digital camera systems. The first, a high speed Phantom 7 camera with a Video Scope HS 1845 HS image intensifier coupled with an 50mm lens provides fast frame rates with data recorded at 200 and 400 frames per second with a 512x384 pixel, 11.8x8.8 degree FOV. The second system is an Andor Electron-Multiplying Charge Couple Device (EMCCD) running at 33 frames per second using a 256 by 256 format covering 16x16 degrees field of view. Both systems made observations of flickering aurora in the magnetic zenith, using optical filters transmitting the prompt blue and red emissions of nitrogen. The Andor system was deployed at the Poker Flat rocket range near Fairbanks AK, while the Phantom system was deployed approximately 400 miles north of Poker Flat at Toolik Lake observatory. We find both narrow band low frequency (~5-10 Hz) and wider band, higher frequency (50- 70 Hz) oscillations in the optical intensity of flickering aurora. Direct comparison of the optical data and the dispersion relation for ion cyclotron waves thought to be responsible for the modulation of electrons causing the intensity fluctuations seen in flickering aurora are presented.

  16. High speed ground transportation study. Executive summary

    SciTech Connect

    Not Available

    1992-10-01

    In 1991, the Washington State Legislature enacted Chapter 231, Laws of 1991 (SHB 1452), which directed that a comprehensive assessment be made of the feasibility of developing a high speed ground transportation (HSGT) system in the State of Washington. The legislation came about because there was a growing recognition that major transportation corridors were reaching unacceptable levels of congestion, and that even though most large metropolitan areas were developing specific plans to ease that congestion within their urban boundaries, intercity travel between those areas was becoming increasingly difficult. The study area included the State of Washington plus the Portland, OR urban area and the lower mainland of British Columbia. Two major corridors were identified and analyzed. The study was not meant to focus on the technologies but rather on the economic, environmental, institutional and financial feasibility of implementing HSGT in this state. The study was not meant to be a siting study. Alignments and station locations were assumed only to test feasibility, and to evaluate corridors and service areas. Specific location decisions will require more detailed engineering and operations studies.

  17. Enhanced high-speed coherent diffraction imaging

    NASA Astrophysics Data System (ADS)

    Potier, Jonathan; Fricker, Sebastien; Idir, Mourad

    2011-03-01

    Due to recent advances in X-ray microscopy, we are now able to image objects with nanometer resolution thanks to Synchrotron beam lines or Free Electron Lasers (FEL). The PCI (Phase Contrast Imaging) is a robust technique that can recover the wavefront from measurements of only few intensity pictures in the Fresnel diffraction region. With our fast straightforward calculus methods, we manage to provide the phase induced by a microscopic specimen in few seconds. We can therefore obtain high contrasted images from transparent materials at very small scales. To reach atomic resolution imaging and thus make a transition from the near to the far field, the Coherent Diffraction Imaging (CDI) technique finds its roots in the analysis of diffraction patterns to obtain the phase of the altered complex wave. Theoretical results about existence and uniqueness of this retrieved piece of information by both iterative and direct algorithms have already been released. However, performances of algorithms remain limited by the coherence of the X-ray beam, presence of random noise and the saturation threshold of the detector. We will present reconstructions of samples using an enhanced version of HIO algorithm improving the speed of convergence and its repeatability. As a first step toward a practical X-Ray CDI system, initial images for reconstructions are acquired with the laser-based CDI system working in the visible spectrum.

  18. High speed curved position sensitive detector

    DOEpatents

    Hendricks, Robert W.; Wilson, Jack W.

    1989-01-01

    A high speed curved position sensitive porportional counter detector for use in x-ray diffraction, the detection of 5-20 keV photons and the like. The detector employs a planar anode assembly of a plurality of parallel metallic wires. This anode assembly is supported between two cathode planes, with at least one of these cathode planes having a serpentine resistive path in the form of a meander having legs generally perpendicular to the anode wires. This meander is produced by special microelectronic fabrication techniques whereby the meander "wire" fans outwardly at the cathode ends to produce the curved aspect of the detector, and the legs of the meander are small in cross-section and very closely spaced whereby a spatial resolution of about 50 .mu.m can be achieved. All of the other performance characteristics are about as good or better than conventional position sensitive proportional counter type detectors. Count rates of up to 40,000 counts per second with 0.5 .mu.s shaping time constants are achieved.

  19. 8-Foot High Speed Tunnel (HST)

    NASA Image and Video Library

    1957-03-19

    Interior view of the slotted throat test section installed in the 8-Foot High Speed Tunnel (HST) in 1950. The slotted region is about 160 inches in length. In this photograph, the sting-type model support is seen straight on. In a NASA report, the test section is described as follows: The test section of the Langley 8-foot transonic tunnel is dodecagonal in cross section and has a cross-sectional area of about 43 square feet. Longitudinal slots are located between each of the 12 wall panels to allow continuous operation through the transonic speed range. The slots contain about 11 percent of the total periphery of the test section. Six of the twelve panels have windows in them to allow for schlieren observations. The entire test section is enclosed in a hemispherical shaped chamber. John Becker noted that the tunnel s final achievement was the development and use in routine operations of the first transonic slotted throat. The investigations of wing-body shapes in this tunnel led to Whitcomb s discovery of the transonic area rule. James Hansen described the origins of the the slotted throat as follows: In 1946 Langley physicist Ray H. Wright conceived a way to do transonic research effectively in a wind tunnel by placing slots in the throat of the test section. The concept for what became known as the slotted-throat or slotted-wall tunnel came to Wright not as a solution to the chronic transonic problem, but as a way to get rid of wall interference (i.e., the mutual effect of two or more meeting waves or vibrations of any kind caused by solid boundaries) at subsonic speeds. For most of the year before Wright came up with this idea, he had been trying to develop a theoretical understanding of wall interference in the 8-Foot HST, which was then being repowered for Mach 1 capability. When Wright presented these ideas to John Stack, the response was enthusiastic but neither Wright nor Stack thought of slotted-throats as a solution to the transonic problem, only the

  20. Effect of wheelset flexibility on wheel-rail contact behavior and a specific coupling of wheel-rail contact to flexible wheelset

    NASA Astrophysics Data System (ADS)

    Zhong, Shuoqiao; Xiao, Xinbiao; Wen, Zefeng; Jin, Xuesong

    2016-04-01

    The flexibility of a train's wheelset can have a large effect on vehicle-track dynamic responses in the medium to high frequency range. To investigate the effects of wheelset bending and axial deformation of the wheel web, a specific coupling of wheel-rail contact with a flexible wheelset is presented and integrated into a conventional vehicle-track dynamic system model. Both conventional and the proposed dynamic system models are used to carry out numerical analyses on the effects of wheelset bending and axial deformation of the wheel web on wheel-rail rolling contact behaviors. Excitations with various irregularities and speeds were considered. The irregularities included measured track irregularity and harmonic irregularities with two different wavelengths. The speeds ranged from 200 to 400 km/h. The results show that the proposed model can characterize the effects of flexible wheelset deformation on the wheel-rail rolling contact behavior very well.

  1. A new solution method for wheel/rail rolling contact.

    PubMed

    Yang, Jian; Song, Hua; Fu, Lihua; Wang, Meng; Li, Wei

    2016-01-01

    To solve the problem of wheel/rail rolling contact of nonlinear steady-state curving, a three-dimensional transient finite element (FE) model is developed by the explicit software ANSYS/LS-DYNA. To improve the solving speed and efficiency, an explicit-explicit order solution method is put forward based on analysis of the features of implicit and explicit algorithm. The solution method was first applied to calculate the pre-loading of wheel/rail rolling contact with explicit algorithm, and then the results became the initial conditions in solving the dynamic process of wheel/rail rolling contact with explicit algorithm as well. Simultaneously, the common implicit-explicit order solution method is used to solve the FE model. Results show that the explicit-explicit order solution method has faster operation speed and higher efficiency than the implicit-explicit order solution method while the solution accuracy is almost the same. Hence, the explicit-explicit order solution method is more suitable for the wheel/rail rolling contact model with large scale and high nonlinearity.

  2. Chromotomosynthesis for high speed hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Bostick, Randall L.; Perram, Glen P.

    2012-09-01

    A rotating direct vision prism, chromotomosynthetic imaging (CTI) system operating in the visible creates hyperspectral imagery by collecting a set of 2D images with each spectrally projected at a different rotation angle of the prism. Mathematical reconstruction techniques that have been well tested in the field of medical physics are used to reconstruct the data to produce the 3D hyperspectral image. The instrument operates with a 100 mm focusing lens in the spectral range of 400-900 nm with a field of view of 71.6 mrad and angular resolution of 0.8-1.6 μrad. The spectral resolution is 0.6 nm at the shortest wavelengths, degrading to over 10 nm at the longest wavelengths. Measurements using a pointlike target show that performance is limited by chromatic aberration. The accuracy and utility of the instrument is assessed by comparing the CTI results to spatial data collected by a wideband image and hyperspectral data collected using a liquid crystal tunable filter (LCTF). The wide-band spatial content of the scene reconstructed from the CTI data is of same or better quality as a single frame collected by the undispersed imaging system with projections taken at every 1°. Performance is dependent on the number of projections used, with projections at 5° producing adequate results in terms of target characterization. The data collected by the CTI system can provide spatial information of equal quality as a comparable imaging system, provide high-frame rate slitless 1-D spectra, and generate 3-D hyperspectral imagery which can be exploited to provide the same results as a traditional multi-band spectral imaging system. While this prototype does not operate at high speeds, components exist which will allow for CTI systems to generate hyperspectral video imagery at rates greater than 100 Hz. The instrument has considerable potential for characterizing bomb detonations, muzzle flashes, and other battlefield combustion events.

  3. High Speed Dynamics in Brittle Materials

    NASA Astrophysics Data System (ADS)

    Hiermaier, Stefan

    2015-06-01

    Brittle Materials under High Speed and Shock loading provide a continuous challenge in experimental physics, analysis and numerical modelling, and consequently for engineering design. The dependence of damage and fracture processes on material-inherent length and time scales, the influence of defects, rate-dependent material properties and inertia effects on different scales make their understanding a true multi-scale problem. In addition, it is not uncommon that materials show a transition from ductile to brittle behavior when the loading rate is increased. A particular case is spallation, a brittle tensile failure induced by the interaction of stress waves leading to a sudden change from compressive to tensile loading states that can be invoked in various materials. This contribution highlights typical phenomena occurring when brittle materials are exposed to high loading rates in applications such as blast and impact on protective structures, or meteorite impact on geological materials. A short review on experimental methods that are used for dynamic characterization of brittle materials will be given. A close interaction of experimental analysis and numerical simulation has turned out to be very helpful in analyzing experimental results. For this purpose, adequate numerical methods are required. Cohesive zone models are one possible method for the analysis of brittle failure as long as some degree of tension is present. Their recent successful application for meso-mechanical simulations of concrete in Hopkinson-type spallation tests provides new insight into the dynamic failure process. Failure under compressive loading is a particular challenge for numerical simulations as it involves crushing of material which in turn influences stress states in other parts of a structure. On a continuum scale, it can be modeled using more or less complex plasticity models combined with failure surfaces, as will be demonstrated for ceramics. Models which take microstructural

  4. Application of high-temperature extraction in a carrier gas for a quantitative determination of TiN in rail steel

    NASA Astrophysics Data System (ADS)

    Tabakov, Ya. I.; Grigorovich, K. V.; Rumyantsev, B. A.

    2016-11-01

    The possibility of application of high-temperature extraction in a carrier gas to determine the content of nitrogen from titanium nitride inclusions in rail steel specimens of industrial melts and model alloys is considered. The temperatures of the onset of the dissociation of basic nitrides in rail steel are calculated under the conditions of a carbon-saturated melt. The nitrogen content in titanium nitrides in rail steel is calculated under the equilibrium conditions in the system. The experimental and calculated data on the characteristic temperatures of TiN dissociation and the nitrogen content in TiN are compared. A satisfactory convergence of the calculated and experimental data is obtained. The possibility of application of high-temperature extraction in a graphite crucible in a carrier gas flow for fractional analysis of nitrides in steel is shown.

  5. Calibration of GPS based high accuracy speed meter for vehicles

    NASA Astrophysics Data System (ADS)

    Bai, Yin; Sun, Qiao; Du, Lei; Yu, Mei; Bai, Jie

    2015-02-01

    GPS based high accuracy speed meter for vehicles is a special type of GPS speed meter which uses Doppler Demodulation of GPS signals to calculate the speed of a moving target. It is increasingly used as reference equipment in the field of traffic speed measurement, but acknowledged standard calibration methods are still lacking. To solve this problem, this paper presents the set-ups of simulated calibration, field test signal replay calibration, and in-field test comparison with an optical sensor based non-contact speed meter. All the experiments were carried out on particular speed values in the range of (40-180) km/h with the same GPS speed meter. The speed measurement errors of simulated calibration fall in the range of +/-0.1 km/h or +/-0.1%, with uncertainties smaller than 0.02% (k=2). The errors of replay calibration fall in the range of +/-0.1% with uncertainties smaller than 0.10% (k=2). The calibration results justify the effectiveness of the two methods. The relative deviations of the GPS speed meter from the optical sensor based noncontact speed meter fall in the range of +/-0.3%, which validates the use of GPS speed meter as reference instruments. The results of this research can provide technical basis for the establishment of internationally standard calibration methods of GPS speed meters, and thus ensures the legal status of GPS speed meters as reference equipment in the field of traffic speed metrology.

  6. A novel optical apparatus for the study of rolling contact wear/fatigue based on a high-speed camera and multiple-source laser illumination.

    PubMed

    Bodini, I; Sansoni, G; Lancini, M; Pasinetti, S; Docchio, F

    2016-08-01

    Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens.

  7. A novel optical apparatus for the study of rolling contact wear/fatigue based on a high-speed camera and multiple-source laser illumination

    NASA Astrophysics Data System (ADS)

    Bodini, I.; Sansoni, G.; Lancini, M.; Pasinetti, S.; Docchio, F.

    2016-08-01

    Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens.

  8. High Speed Balancing Applied to the T700 Engine

    NASA Technical Reports Server (NTRS)

    Walton, J.; Lee, C.; Martin, M.

    1989-01-01

    The work performed under Contracts NAS3-23929 and NAS3-24633 is presented. MTI evaluated the feasibility of high-speed balancing for both the T700 power turbine rotor and the compressor rotor. Modifications were designed for the existing Corpus Christi Army Depot (CCAD) T53/T55 high-speed balancing system for balancing T700 power turbine rotors. Tests conducted under these contracts included a high-speed balancing evaluation for T700 power turbines in the Army/NASA drivetrain facility at MTI. The high-speed balancing tests demonstrated the reduction of vibration amplitudes at operating speed for both low-speed balanced and non-low-speed balanced T700 power turbines. In addition, vibration data from acceptance tests of T53, T55, and T700 engines were analyzed and a vibration diagnostic procedure developed.

  9. High Speed Link Radiated Emission Reduction

    NASA Astrophysics Data System (ADS)

    Bisognin, P.; Pelissou, P.; Cissou, R.; Giniaux, M.; Vargas, O.

    2016-05-01

    To control the radiated emission of high-speed link and associated unit, the current approach is to implement overall harness shielding on cables bundles. This method is very efficient in the HF/ VHF (high frequency/ very high frequency) and UHF (ultra-high frequency) ranges when the overall harness shielding is properly bonded on EMC back-shell. Unfortunately, with the increasing frequency, the associated half wavelength matches with the size of Sub-D connector that is the case for the L band. Therefore, the unit connectors become the main source of interference emission. For the L-band and S-band, the current technology of EMC back-shell leaves thin aperture matched with the L band half wavelength and therefore, the shielding effectiveness is drastically reduced. In addition, overall harness shielding means significant increases of the harness mass.Airbus D&S Toulouse and Elancourt investigated a new solution to avoid the need of overall harness shielding. The objective is to procure EM (Electro-Magnetic) clean unit connected to cables bundles free of any overall harness shielding. The proposed solution is to implement EMC common mode filtering on signal interfaces directly on unit PCB as close as possible the unit connector.Airbus D&S Elancourt designed and manufactured eight mock-ups of LVDS (Low Voltage Differential Signaling) interface PCBs' with different solutions of filtering. After verification of the signal integrity, three mock-ups were retained (RC filter and two common mode choke coil) in addition to the reference one (without EMC filter).Airbus D&S Toulouse manufactured associated LVDS cable bundles and integrated the RX (Receiver) and TX (Transmitter) LVDS boards in shielded boxes.Then Airbus D&S performed radiated emission measurement of the LVDS links subassemblies (e.g. RX and TX boxes linked by LVDS cables) according to the standard test method. This paper presents the different tested solutions and main conclusions on the feasibility of such

  10. USDOE Top-of-Rail Lubricant Project

    SciTech Connect

    Mohumad F. Alzoubi; George R. Fenske; Robert A. Erck; Amrit S. Boparai

    2002-02-01

    Lubrication of wheel/rail systems has been recognized for the last two decades as a very important issue for railroads. Energy savings and less friction and wear can be realized if a lubricant can be used at the wheel/rail interface. On the other hand, adverse influences are seen in operating and wear conditions if improper or excessive lubrication is used. Also, inefficiencies in lubrication need to be avoided for economic and environmental reasons. The top-of-rail (TOR) lubricant concept was developed by Texaco Corporation to lubricate wheels and rails effectively and efficiently. Tranergy Corporation has been developing its SENTRAEN 2000{trademark} lubrication system for the last ten years, and this revolutionary new high-tech on-board rail lubrication system promises to dramatically improve the energy efficiency, performance, safety, and track environment of railroads. The system is fully computer-controlled and ensures that all of the lubricant is consumed as the end of the train passes. Lubricant quantity dispensed is a function of grade, speed, curve, and axle load. Tranergy also has its LA4000{trademark} wheel and rail simulator, a lubrication and traction testing apparatus. The primary task of this project was collecting and analyzing the volatile and semivolatile compounds produced as the lubricant was used. The volatile organic compounds were collected by Carbotrap cartridges and analyzed by adsorption and gas chromatography/mass spectrometry (GC/MS). The semivolatile fraction was obtained by collecting liquid that dripped from the test wheel. The collected material was also analyzed by GC/MS. Both of these analyses were qualitative. The results indicated that in the volatile fraction, the only compounds on the Environmental Protection Agency's (EPA) Superfund List of Analytes detected were contaminants either in the room air or from other potential contamination sources in the laboratory. Similarly, in the semivolatile fraction none of the detected

  11. High Speed, High Accuracy Stage for Advanced Lithography. Phase I

    DTIC Science & Technology

    2007-11-02

    noise and 5nm LSB of our laser interferometer. Zerodur Mounting bar Base expended in this direction Sensor heads Interferometer mirror ...state of the art. Their CORE machine claims an accuracy of 80nm over a 6- inch square field. This machine uses high-speed mirrors to scan multiple...variety of optical paths. If the laboratory is not quiet (e.g. if the interferometer mirror is moving, or if people are talking in the laboratory

  12. High speed flow cytometric separation of viable cells

    DOEpatents

    Sasaki, Dennis T.; Van den Engh, Gerrit J.; Buckie, Anne-Marie

    1995-01-01

    Hematopoietic cell populations are separated to provide cell sets and subsets as viable cells with high purity and high yields, based on the number of original cells present in the mixture. High-speed flow cytometry is employed using light characteristics of the cells to separate the cells, where high flow speeds are used to reduce the sorting time.

  13. High speed flow cytometric separation of viable cells

    DOEpatents

    Sasaki, D.T.; Van den Engh, G.J.; Buckie, A.M.

    1995-11-14

    Hematopoietic cell populations are separated to provide cell sets and subsets as viable cells with high purity and high yields, based on the number of original cells present in the mixture. High-speed flow cytometry is employed using light characteristics of the cells to separate the cells, where high flow speeds are used to reduce the sorting time.

  14. Measurements of speed of response of high-speed visible and IR optical detectors

    NASA Technical Reports Server (NTRS)

    Rowe, H. E.; Osmundson, J. S.

    1972-01-01

    A technique for measuring speed of response of high speed visible and IR optical detectors to mode-locked Nd:YAG laser pulses is described. Results of measurements of response times of four detectors are presented. Three detectors that can be used as receivers in a 500-MHz optical communication system are tested.

  15. Water Containment Systems for Testing High-Speed Flywheels

    NASA Technical Reports Server (NTRS)

    Trase, Larry; Thompson, Dennis

    2006-01-01

    Water-filled containers are used as building blocks in a new generation of containment systems for testing high-speed flywheels. Such containment systems are needed to ensure safety by trapping high-speed debris in the event of centrifugal breakup or bearing failure. Traditional containment systems for testing flywheels consist mainly of thick steel rings. The effectiveness of this approach to shielding against high-speed debris was demonstrated in a series of tests.

  16. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false High-speed craft. 84.24 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at a...

  17. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false High-speed craft. 84.24 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at a...

  18. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false High-speed craft. 84.24 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at a...

  19. High-speed dual Langmuir probe.

    PubMed

    Lobbia, Robert B; Gallimore, Alec D

    2010-07-01

    In an effort to temporally resolve the electron density, electron temperature, and plasma potential for turbulent plasma discharges, a unique high-speed dual Langmuir probe (HDLP) has been developed. A traditional single Langmuir probe of cylindrical geometry (exposed to the plasma) is swept simultaneously with a nearby capacitance and noise compensating null probe (fully insulated from the plasma) to enable bias sweep rates on a microsecond timescale. Traditional thin-sheath Langmuir probe theory is applied for interpretation of the collected probe data. Data at a sweep rate of 100 kHz are presented; however the developed system is capable of running at 1 MHz-near the upper limit of the applied electrostatic Langmuir probe theory for the investigated plasma conditions. Large sets (100,000 sweeps at each of 352 spatial locations) of contiguous turbulent plasma properties are collected using simple electronics for probe bias driving and current measurement attaining 80 dB signal-to-noise measurements with dc to 1 MHz bandwidth. Near- and far-field plume measurements with the HDLP system are performed downstream from a modern Hall effect thruster where the time-averaged plasma properties exhibit the approximate ranges: electron density n(e) from (1x10(15))-(5x10(16)) m(-3), electron temperature T(e) from 1 to 3.5 eV, and plasma potential V(p) from 5 to 15 V. The thruster discharge of 200 V (constant anode potential) and 2 A (average discharge current) displays strong, 2.2 A peak-to-peak, current oscillations at 19 kHz, characteristic of the thruster "breathing mode" ionization instability. Large amplitude discharge current fluctuations are typical for most Hall thrusters, yet the HDLP system reveals the presence of the same 19 kHz fluctuations in n(e)(t), T(e)(t), and V(p)(t) throughout the entire plume with peak-to-peak divided by mean plasma properties that average 94%. The propagation delays between the discharge current fluctuations and the corresponding plasma

  20. High speed data transmission for the SSC solenoidal detector

    NASA Astrophysics Data System (ADS)

    Leskovar, B.

    1991-04-01

    High speed data transmission using fiber optics for the Superconducting Super Collider solenoidal detector has been studied. The solenoidal detector system will consist of nine subsystems involving more than a total 10(exp 7) channels of readout electronics. Consequently, a new high performance data acquisition system, incorporating high-speed optical fiber networks, will be required to process this large quantity of data.

  1. Safety of high speed guided ground transportation systems: Magnetic and electric field testing of the massachusetts bay transportation authority (MBTA) urban transit system. Volume 1. Analysis. Final report, September 1992-March 1993

    SciTech Connect

    Dietrich, F.M.; Papas, P.N.; Ferro, W.E.; Jacobs, W.L.; Steiner, G.A.

    1993-06-01

    The safety of magnetically levitated (maglev) and high speed rail (HSR) trains proposed for application in the United States is the responsibility of the Federal Railroad Administration (FRA). Plans for near future US applications include maglev projects (e.g. in Orlando, FL and Pittsburgh, PA) and high speed rail (the French Train a Grande Vitesse (TGV) in the Texas Triangle). Concerns exist regarding the potential safety, environmental and health effects on the public and on transportation workers due to electrification along new or existing rail corridors, and to maglev and high speed rail operations. Therefore, the characterization of electric and magnetic fields (EMF) produced by both steady (dc) and alternating currents (ac) at power frequency (50 Hz in Europe and 60 Hz in the U.S.) and above, in the Extreme Low Frequency (ELF) range (3-3000 Hz) is of interest. A portable magnetic field monitoring system (augmented to include an electric fields probe) was used to sample, record and store 3 axis static and ac magnetic fields waveforms simultaneously, at multiple locations.

  2. Time optimal paths for high speed maneuvering

    SciTech Connect

    Reister, D.B.; Lenhart, S.M.

    1993-01-01

    Recent theoretical results have completely solved the problem of determining the minimum length path for a vehicle with a minimum turning radius moving from an initial configuration to a final configuration. Time optimal paths for a constant speed vehicle are a subset of the minimum length paths. This paper uses the Pontryagin maximum principle to find time optimal paths for a constant speed vehicle. The time optimal paths consist of sequences of axes of circles and straight lines. The maximum principle introduces concepts (dual variables, bang-bang solutions, singular solutions, and transversality conditions) that provide important insight into the nature of the time optimal paths. We explore the properties of the optimal paths and present some experimental results for a mobile robot following an optimal path.

  3. High-speed optical 3D sensing and its applications

    NASA Astrophysics Data System (ADS)

    Watanabe, Yoshihiro

    2016-12-01

    This paper reviews high-speed optical 3D sensing technologies for obtaining the 3D shape of a target using a camera. The focusing speed is from 100 to 1000 fps, exceeding normal camera frame rates, which are typically 30 fps. In particular, contactless, active, and real-time systems are introduced. Also, three example applications of this type of sensing technology are introduced, including surface reconstruction from time-sequential depth images, high-speed 3D user interaction, and high-speed digital archiving.

  4. High-speed ground transportation: some current and future alternatives

    SciTech Connect

    Morita, T.

    1984-01-01

    High-speed ground transportation (HSGT), the value of time, and the social and technological considerations of inter-city transportation are discussed in this article. A particularly promising mode of high-speed ground transportation (MAGLEV) is discussed in some detail. An average speed for HSGT service, 400 kilometers per hour, seems to be attainable. In conclusion, the proposal for a hypersonic subway will be analyzed. 2 figures, 1 table.

  5. Kevlar Properties Investigation High Speed Abrasion Resistance

    DTIC Science & Technology

    1980-02-01

    leading edge of the warp knuckle . These fibers were obviously flattened and smeared at the tips due to abrasion. The lack of severe cracking and...Parallel Configuration at a Speed of 160 fps Using a Contact Force of 15 Lb and a Contact Time of 30 Seconds 68 Photographs of Scorched Knuckle and...of filaments were protruding from the yarn knuckles giving the yarn an open appearance. Figure 4B shows photographs of the piled and unpiled surfaces

  6. High Speed Cascadable Signal Processing Circuits

    DTIC Science & Technology

    1988-04-29

    Mexico 88002 / "’ . Otavio J. Morales . Assistant Principal Investigator ~, . - .-" " The views, opinions, and/or findings contained in this report...T Fort Collins, Colorado 80525 U.S.Army White Sands Missile Ranpe New Mexico 88002-91h3 go. NAME OF FUNDING i SPONSOXINd 9b. OFFICE SYMBOL 9...general purpos; data processor. The Vector Processing Hardware ( VPH ) is a speed-optimized architecture capable of processing vectors of complex data. The

  7. 78 FR 31628 - Environmental Impact Statement for the Milwaukee, WI to Minneapolis, MN Rail Corridor

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-24

    ... Minneapolis-St. Paul, MN (Milwaukee-Twin Cities) High-Speed Rail Corridor Program. The original project... issues at Minneapolis-St. Paul International Airport and Milwaukee's General Mitchell International..., St. Paul, MN 55155, telephone (651) 366- 3193; or Ms. Colleen Vaughn, Office of Railroad Policy...

  8. High loading, low speed fan study, 5

    NASA Technical Reports Server (NTRS)

    Keenan, M. J.; Burdsall, E. A.

    1973-01-01

    A low speed, low noise, single stage fan was designed and tested. Design pressure ratio was 1.5 at a rotor tip speed of 1000 ft/sec. No inlet guide vane was used, the rotor stator was spaced and the number of rotor and stator airfoils was selected for low noise. Tests were conducted with uniform and distorted inlet flows. Stall margin of the initial design was too low for practical application. Airfoil slots and boundary layer and endwall devices did not improve stall margin sufficiently. A redesigned stator with reduced loadings increased stall margin, giving a fan efficiency of 0.883, 15% stall margin, and a 1.474 pressure radio at a specific flow of 41.7 lb/sec sq ft. Casing treatment over rotor tips improved stall margin with distorted inlet flow; vortex generators did not. Blade passing frequency noise increased with rotor relative Mach number. No supersonic fan noise was measured below 105% of design speed. Slotting airfoils, casing treatments, and a reduction of the ratio (number-stators/number-rotors) from (2n + 16) to (2n + 2) had no significant effects on noise.

  9. High-speed optical correlator with coaxial holographic system

    NASA Astrophysics Data System (ADS)

    Ikeda, Kanami; Watanabe, Eriko

    2015-09-01

    A high-speed volume holographic optical correlator is developed, which takes advantage of a coaxial holographic system. We have realized this high-speed correlator using an optimal design of the signal pattern, which improves the shift multiplex recording shift pitch. The speed of this correlator was further improved by increasing the number of pixels in the spatial light modulator and using a high speed rotating actuator. This correlation system successfully achieved an equal error rate of 0% by performing optical correlation over 900 times. It also achieved optical correlation experiment, at a shift pitch of 2.45 µm and a disk rotation speed of 900 rpm. In terms of optical correlation calculation speed, it yielded a peak interval of 542 ns, which corresponds to 1.846 × 106 frames per second.

  10. Structural vulnerability and intervention of high speed railway networks

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhua; Hu, Funian; Wang, Shuliang; Dai, Yang; Wang, Yixing

    2016-11-01

    This paper employs complex network theory to assess the structural vulnerability of high speed railway networks subjected to two different malicious attacks. Chinese, US and Japanese high speed railway networks are used to discuss the vulnerable characteristics of systems. We find that high speed railway networks are very fragile when suffering serious disturbances and two attack rules can cause analogous damages to one high speed railway network, which illustrates that the station with large degree possesses high betweenness, vice versa. Meanwhile, we discover that Japanese high speed railway network has the best global connectivity, but Chinese high speed railway network has the best local connectivity and possesses the largest transport capacity. Moreover, we find that there exist several redundant paths in Chinese high speed railway network and discover the critical stations of three HSRNs. Furthermore, the nearest-link method is adopted to implement topological interventions and to improve the connectivity and reliability of high speed railway networks. In addition, the feasibility and effectiveness of topological interventions are shown by simulations.

  11. High-speed wireless optical LANs

    NASA Astrophysics Data System (ADS)

    Oe, Kunishige; Sato, Syuichi; Okayama, Motoyuki; Kubota, Toshihiro

    2001-11-01

    Study on high speed indoor wireless optical LAN system enabling 100Mbps signal transmission with low bit error rate (10-9) is presented. To realize the optical LAN system handling 100 Mbps signal, a directed line of sight (LOS) system is adopted as the optical receiver sensitivity for a bit error rate of 10-9 for 100 Mbps signals is fairly large. In the system, new approaches are introduced: WDM technology which enables bi-directional transmission in full duplex manner is applied using a 1.3 micrometers laser diode for down-link and 0.65 micrometers red laser diode for up-link light sources. As the wavelengths of the two lasers are quite separated from each other, this WDM technology brings an advantage that two kind of semiconductor materials can be used for detectors; GaInAs is used for down-link while Si is applied for up-link. GaInAs PD cannot detect the up-link laser light of 0.65 micrometers and Si PD or APD cannot detect the down-link laser light of 1.3micrometers . Therefore full duplex transmission can be achieved in this configuration. In the indoor wireless optical LAN system, one of the critical points is the transmitter configuration for down- link which enables to deliver optical power enough for 100 Mbps transmission to user areas as wide as possible with inexpensive prices. To realize the point, a special 1.3micrometers laser diode, a spot-size converter integrated laser (SS-LD), is introduced in company with convex lens and an object lens to deliver optical power to areas as wide as possible. As the far-field patterns of the SS-LD are fairly narrow, most of the output power of the LD could be collected to and spread wide by the object lens of 40 magnifications. Using the device, 3m diameter circle area in the plane 2m apart from the 1.3micrometers SS-LD emitting 20 mW optical power, could receive optical power above the receiver sensitivity for a bit error rate of 10-9 for 100 Mbps signals. The visible red light is convenient for not only position

  12. High-resolution high-speed panoramic cardiac imaging system

    PubMed Central

    Evertson (In Memoriam), Dale W.; Holcomb, Mark R.; Eames, Matthew D.C.; Bray, Mark-Anthony P.; Sidorov, Veniamin Y.; Xu, Junkai; Wingard, Holley; Dobrovolny, Hana M.; Woods, Marcella C.; Gauthier, Daniel J.; Wikswo, John P.

    2008-01-01

    A panoramic cardiac imaging system consisting of three high-speed CCD cameras has been developed to image the surface electrophysiology of a rabbit heart via fluorescence imaging using a voltage-sensitive fluorescent dye. A robust, unique mechanical system was designed to accommodate the three cameras and to adapt to the requirements of future experiments. A unified computer interface was created for this application – a single workstation controls all three CCD cameras, illumination, and stimulation, and the stepping motor rotates the heart. The geometric reconstruction algorithms were adapted from a previous cardiac imaging system. We demonstrate the system by imaging a polymorphic cardiac tachycardia. PMID:18334422

  13. The Advantages of ISDN for High-Speed Remote Access.

    ERIC Educational Resources Information Center

    Galvin, Mark; Hauf, Al

    1997-01-01

    Explains why ISDN (integrated services digital network) is the most practical solution for high-speed remote access, including reliability, cost, flexibility, scaleability, standards, and manageability. Other data transmission options are discussed, including asymmetric digital subscriber lines (ADSL), high-speed digital subscriber lines (HDSL),…

  14. HIGH-SPEED GC/MS FOR AIR ANALYSIS

    EPA Science Inventory

    High speed or fast gas chromatography (FGC) consists of narrow bandwidth injection into a high-speed carrier gas stream passing through a short column leading to a fast detector. Many attempts have been made to demonstrate FGC, but until recently no practical method for routin...

  15. Seakeeping Analysis of Small Displacement High-Speed Vessels

    DTIC Science & Technology

    2003-03-01

    72 73 74 75 76 77 78 79 80 81 82 83 VI. LIST OF REFERENCES [1] Kennell, Colen. Design ... trends in High-Speed Transport. Marine Technology, Vol. 35, No. 3, July 1998, pp.127-134. [2] Ritter, Owen K., Templeman, Michael T. High-Speed

  16. HIGH-SPEED GC/MS FOR AIR ANALYSIS

    EPA Science Inventory

    High speed or fast gas chromatography (FGC) consists of narrow bandwidth injection into a high-speed carrier gas stream passing through a short column leading to a fast detector. Many attempts have been made to demonstrate FGC, but until recently no practical method for routin...

  17. High-Speed Video Analysis of Damped Harmonic Motion

    ERIC Educational Resources Information Center

    Poonyawatpornkul, J.; Wattanakasiwich, P.

    2013-01-01

    In this paper, we acquire and analyse high-speed videos of a spring-mass system oscillating in glycerin at different temperatures. Three cases of damped harmonic oscillation are investigated and analysed by using high-speed video at a rate of 120 frames s[superscript -1] and Tracker Video Analysis (Tracker) software. We present empirical data for…

  18. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of the isosceles triangle formed by the side lights and masthead light when seen in end elevation is... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at...

  19. 33 CFR 84.24 - High-speed craft.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of the isosceles triangle formed by the side lights and masthead light when seen in end elevation is... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at...

  20. High-Speed Video Analysis of Damped Harmonic Motion

    ERIC Educational Resources Information Center

    Poonyawatpornkul, J.; Wattanakasiwich, P.

    2013-01-01

    In this paper, we acquire and analyse high-speed videos of a spring-mass system oscillating in glycerin at different temperatures. Three cases of damped harmonic oscillation are investigated and analysed by using high-speed video at a rate of 120 frames s[superscript -1] and Tracker Video Analysis (Tracker) software. We present empirical data for…

  1. High Speed Sonar Array Depressor Program

    DTIC Science & Technology

    1981-11-30

    were conducted in the Exuma Sound In August 1981. 33 Report 12482 1000 4000 z 3000 2000 - 500 1000 0 1I 0 0 5 10 15 20 25 30 SPEED-KNOTS 700 1:11 IS z...the ONR Sea Trial 1A6 on the R/V ATHENA. The depressor was deployed during that portion of the trials occuring on 5, 6, 7 and 8 August 1981 in Exuma ...Before the Exuma Sound runs the bolt holes in tVe depressor were permanently plugged and faired. From then on no relation was seen between the sign

  2. Spontaneous sidebanding in high speed rotordynamics

    NASA Astrophysics Data System (ADS)

    Ehrich, F. F.

    1992-10-01

    It is noted that the spontaneous sideband spacing frequency seems to be a whole number fraction (1/J) of the operating speed which indicates that the wave form is periodic and completes a full cycle every J rotations of the rotor. Employing a numerical model of a rotor that simulates local contact with a stator in close proximity as a bilinear spring, studies have been conducted to explore the circumstances for this spontaneous sidebanding. Two general classes of this type of response are determined in a system that is effectively single-degree-of-freedom.

  3. High speed all-optical networks

    NASA Technical Reports Server (NTRS)

    Chlamtac, Imrich

    1993-01-01

    An inherent problem of conventional point-to-point WAN architectures is that they cannot translate optical transmission bandwidth into comparable user available throughput due to the limiting electronic processing speed of the switching nodes. This report presents the first solution to WDM based WAN networks that overcomes this limitation. The proposed Lightnet architecture takes into account the idiosyncrasies of WDM switching/transmission leading to an efficient and pragmatic solution. The Lightnet architecture trades the ample WDM bandwidth for a reduction in the number of processing stages and a simplification of each switching stage, leading to drastically increased effective network throughputs.

  4. Nonparametric analysis of high wind speed data

    NASA Astrophysics Data System (ADS)

    Francisco-Fernández, Mario; Quintela-del-Río, Alejandro

    2013-01-01

    In this paper, nonparametric curve estimation methods are applied to analyze time series of wind speeds, focusing on the extreme events exceeding a chosen threshold. Classical parametric statistical approaches in this context consist in fitting a generalized Pareto distribution (GPD) to the tail of the empirical cumulative distribution, using maximum likelihood or the method of the moments to estimate the parameters of this distribution. Additionally, confidence intervals are usually computed to assess the uncertainty of the estimates. Nonparametric methods to estimate directly some quantities of interest, such as the probability of exceedance, the quantiles or return levels, or the return periods, are proposed. Moreover, bootstrap techniques are used to develop pointwise and simultaneous confidence intervals for these functions. The proposed models are applied to wind speed data in the Gulf Coast of US, comparing the results with those using the GPD approach, by means of a split-sample test. Results show that nonparametric methods are competitive with respect to the standard GPD approximations. The study is completed generating synthetic data sets and comparing the behavior of the parametric and the nonparametric estimates in this framework.

  5. High-Speed Tests of Radial-Engine Cowlings

    NASA Technical Reports Server (NTRS)

    Robinson, Russell G.; Becker, John V.

    1939-01-01

    The drag characteristics of eight radial-engine cowlings have been determined over a wide speed range in the N.A.C.A. 8-foot high-speed wind tunnel. The pressure distribution over all cowlings was measured, to and above the speed of the compressibility burble, as an aid in interpreting the force tests. One-fifth-scale models of radial-engine cowlings on a wing-nacelle combination mere used in the tests.

  6. High-speed OCT light sources and systems [Invited

    PubMed Central

    Klein, Thomas; Huber, Robert

    2017-01-01

    Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems. PMID:28270988

  7. High-Speed Tests of Conventional Radial-Engine Cowlings

    NASA Technical Reports Server (NTRS)

    Robinson, Russell G; Becker, John V

    1942-01-01

    The drag characteristics of eight radial-engine cowlings have been determined over a wide speed range in the NACA 8-foot high-speed wind tunnel. The pressure distribution over all cowlings was measured, to and above the speed of the compressibility burble, as an aid in interpreting the force tests. One-fifth-scale models of radial-engine cowlings on a wing-nacelle combination were used in the tests.

  8. A MHz speed wavelength sweeping for ultra-high speed FBG interrogation

    NASA Astrophysics Data System (ADS)

    Kim, Gyeong Hun; Lee, Hwi Don; Eom, Tae Joong; Jeong, Myung Yung; Kim, Chang-Seok

    2015-09-01

    We demonstrated a MHz speed wavelength-swept fiber laser based on the active mode locking (AML) technique and applied to interrogation system of an array of fiber Bragg grating (FBG) sensors. MHz speed wavelength sweeping of wavelength-swept fiber laser can be obtained by programmable frequency modulation of the semiconductor optical amplifier (SOA) without any wavelength tunable filter. Both static and dynamic strain measurement of FBG sensors were successfully characterized with high linearity of an R-square value of 0.9999 at sweeping speed of 50 kHz.

  9. High speed demodulation systems for fiber optic grating sensors

    NASA Technical Reports Server (NTRS)

    Udd, Eric (Inventor); Weisshaar, Andreas (Inventor)

    2002-01-01

    Fiber optic grating sensor demodulation systems are described that offer high speed and multiplexing options for both single and multiple parameter fiber optic grating sensors. To attain very high speeds for single parameter fiber grating sensors ratio techniques are used that allow a series of sensors to be placed in a single fiber while retaining high speed capability. These methods can be extended to multiparameter fiber grating sensors. Optimization of speeds can be obtained by minimizing the number of spectral peaks that must be processed and it is shown that two or three spectral peak measurements may in specific multiparameter applications offer comparable or better performance than processing four spectral peaks. Combining the ratio methods with minimization of peak measurements allows very high speed measurement of such important environmental effects as transverse strain and pressure.

  10. Thermomechanical simulations and experimental validation for high speed incremental forming

    NASA Astrophysics Data System (ADS)

    Ambrogio, Giuseppina; Gagliardi, Francesco; Filice, Luigino; Romero, Natalia

    2016-10-01

    Incremental sheet forming (ISF) consists in deforming only a small region of the workspace through a punch driven by a NC machine. The drawback of this process is its slowness. In this study, a high speed variant has been investigated from both numerical and experimental points of view. The aim has been the design of a FEM model able to perform the material behavior during the high speed process by defining a thermomechanical model. An experimental campaign has been performed by a CNC lathe with high speed to test process feasibility. The first results have shown how the material presents the same performance than in conventional speed ISF and, in some cases, better material behavior due to the temperature increment. An accurate numerical simulation has been performed to investigate the material behavior during the high speed process confirming substantially experimental evidence.

  11. The use of high-speed imaging in education

    NASA Astrophysics Data System (ADS)

    Kleine, H.; McNamara, G.; Rayner, J.

    2017-02-01

    Recent improvements in camera technology and the associated improved access to high-speed camera equipment have made it possible to use high-speed imaging not only in a research environment but also specifically for educational purposes. This includes high-speed sequences that are created both with and for a target audience of students in high schools and universities. The primary goal is to engage students in scientific exploration by providing them with a tool that allows them to see and measure otherwise inaccessible phenomena. High-speed imaging has the potential to stimulate students' curiosity as the results are often surprising or may contradict initial assumptions. "Live" demonstrations in class or student- run experiments are highly suitable to have a profound influence on student learning. Another aspect is the production of high-speed images for demonstration purposes. While some of the approaches known from the application of high speed imaging in a research environment can simply be transferred, additional techniques must often be developed to make the results more easily accessible for the targeted audience. This paper describes a range of student-centered activities that can be undertaken which demonstrate how student engagement and learning can be enhanced through the use of high speed imaging using readily available technologies.

  12. Substructure method in high-speed monorail dynamic problems

    NASA Astrophysics Data System (ADS)

    Ivanchenko, I. I.

    2008-12-01

    combined schemes modeling a strained elastic compound moving structure and a monorail elevated track. The problems of development of methods for dynamic analysis of monorails are very topical, especially because of increasing speeds of the rolling stock motion. These structures are studied in [16-18]. In the present paper, the above problem is solved by using the method for the moving load analysis and a step procedure of integration with respect to time, which were proposed in [9, 19], respectively. Further, these components are used to enlarge the possibilities of the substructure method in problems of dynamics. In the approach proposed for moving load analysis of structures, for a substructure (having the shape of a boundary element or a superelement) we choose an object moving at a constant speed (a monorail rolling stock); in this case, we use rod boundary elements of large length, which are gathered in a system modeling these objects. In particular, sets of such elements form a model of a monorail rolling stock, namely, carriage hulls, wheeled carts, elements of the wheel spring suspension, models of continuous beams of monorail ways and piers with foundations admitting emergency subsidence and unilateral links. These specialized rigid finite elements with linear and nonlinear links, included into the set of earlier proposed finite elements [14, 19], permit studying unsteady vibrations in the "monorail train-elevated track" (MTET) system taking into account various irregularities on the beam-rail, the pier emergency subsidence, and their elastic support by the basement. In this case, a high degree of the structure spatial digitization is obtained by using rods with distributed parameters in the analysis. The displacements are approximated by linear functions and trigonometric Fourier series, which, as was already noted, permits increasing the number of degrees of freedom of the system under study simultaneously preserving the order of the resolving system of

  13. Traction contact performance evaluation at high speeds

    NASA Technical Reports Server (NTRS)

    Tevaarwerk, J. L.

    1981-01-01

    The results of traction tests performed on two fluids are presented. These tests covered a pressure range of 1.0 to 2.5 GPa, an inlet temperature range of 30 'C to 70 'C, a speed range of 10 to 80 m/sec, aspect ratios of .5 to 5 and spin from 0 to 2.1 percent. The test results are presented in the form of two dimensionless parameters, the initial traction slope and the maximum traction peak. With the use of a suitable rheological fluid model the actual traction curves measured can now be reconstituted from the two fluid parameters. More importantly, the knowledge of these parameters together with the fluid rheological model, allow the prediction of traction under conditions of spin, slip and any combination thereof. Comparison between theoretically predicted traction under these conditions and those measured in actual traction tests shows that this method gives good results.

  14. Thermometry of a high temperature high speed micro heater.

    PubMed

    Xu, M; Slovin, G; Paramesh, J; Schlesinger, T E; Bain, J A

    2016-02-01

    A high temperature high-speed tungsten micro heater was fabricated and tested for application in phase change switches to indirectly heat and transform phase change material. Time domain transmissometry was used to measure heater temperature transients for given electrical inputs. Finite element modeling results on heater temperature transients show a good consistency between experiments and simulations with 0.2% mismatch in the best case and 13.1% in the worst case. The heater described in this work can reliably reach 1664 K at a rate of 1.67 × 10(10) K/s and quench to room temperature with a thermal RC time constant (time for T to fall by a factor of e) of less than 40 ns.

  15. High-Speed, High-Temperature Finger Seal Test Results

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.; Kumar, Arun; Delgado, Irebert R.

    2002-01-01

    Finger seals have significantly lower leakage rates than conventional labyrinth seals used in gas turbine engines and are expected to decrease specific fuel consumption by over 1 percent and to decrease direct operating cost by over 0.5 percent. Their compliant design accommodates shaft growth and motion due to thermal and dynamic loads with minimal wear. The cost to fabricate these finger seals is estimated to be about half the cost to fabricate brush seals. A finger seal has been tested in NASA's High Temperature, High Speed Turbine Seal Test Rig at operating conditions up to 1200 F, 1200 ft/s, and 75 psid. Static, performance and endurance test results are presented. While seal leakage and wear performance are acceptable, further design improvements are needed to reduce the seal power loss.

  16. High speed sampling circuit design for pulse laser ranging

    NASA Astrophysics Data System (ADS)

    Qian, Rui-hai; Gao, Xuan-yi; Zhang, Yan-mei; Li, Huan; Guo, Hai-chao; Guo, Xiao-kang; He, Shi-jie

    2016-10-01

    In recent years, with the rapid development of digital chip, high speed sampling rate analog to digital conversion chip can be used to sample narrow laser pulse echo. Moreover, high speed processor is widely applied to achieve digital laser echo signal processing algorithm. The development of digital chip greatly improved the laser ranging detection accuracy. High speed sampling and processing circuit used in the laser ranging detection system has gradually been a research hotspot. In this paper, a pulse laser echo data logging and digital signal processing circuit system is studied based on the high speed sampling. This circuit consists of two parts: the pulse laser echo data processing circuit and the data transmission circuit. The pulse laser echo data processing circuit includes a laser diode, a laser detector and a high sample rate data logging circuit. The data transmission circuit receives the processed data from the pulse laser echo data processing circuit. The sample data is transmitted to the computer through USB2.0 interface. Finally, a PC interface is designed using C# language, in which the sampling laser pulse echo signal is demonstrated and the processed laser pulse is plotted. Finally, the laser ranging experiment is carried out to test the pulse laser echo data logging and digital signal processing circuit system. The experiment result demonstrates that the laser ranging hardware system achieved high speed data logging, high speed processing and high speed sampling data transmission.

  17. High-speed decimation filter for a delta-sigma analog-to-digital converter

    NASA Astrophysics Data System (ADS)

    Xie, Yiqun

    1998-10-01

    A decimation filter is a key component in a delta-sigma analog-to-digital converter system. The importance of the design of the decimation filter for the delta-sigma converter is due to several factors. The first, high resolution, which is the major advantage of the delta-sigma converter, can only be possible if the decimation filter can remove the high-frequency noise generated by the quantizer, without introducing significant distortion of the signals. The second is that a decimation filter occupies the dominant portion of the area and consumes the dominant portion of power in a delta-sigma converter; therefore, a well designed decimation filter can significantly save power and area for the converter and reduce production cost. The third is that the first-stage decimation filter has to operate in a very high frequency, equal to the sampling frequency of the delta-sigma converter. The circuit complexity and high-speed operation pose challenges to the design of a decimation filter. A superconductive decimation filter has the advantage of allowing sampling the analog signal at an ultra-high frequency in the modulator. This dissertation presents a superconductive decimation filter designed with voltage-state logic, which has the advantage of robustness, being relatively insensitive to clock timing, and easier to interface with semiconductor circuitry than other prevailing superconductive logic families. A structure of a multi-channel-input filter is developed to improve the speed performance. The filter is aimed to work at 16 Gbit/s or higher with state-of-the-art niobium technology. Extensive simulation is performed to optimize the circuit design. Circuit yield is predicted by Monte Carlo simulation using the knowledge of existing process variations. To improve yield, the circuit is simplified by using an accumulate-and-dump structure. A novel XOR gate is invented and used in the circuit to reduce gate count even further. A single-rail operation of signals, rather

  18. Turbomachinery technology for high-speed civil flight

    NASA Technical Reports Server (NTRS)

    Saunders, Neal T.; Glassman, Arthur J.

    1989-01-01

    NASA Lewis' research and technology efforts applicable to turbomachinery for high-speed flight are discussed. The potential benefits and cycle requirements for advanced variable cycle engines and the supersonic throughflow fan engine for a high-speed civil transport application are presented. The supersonic throughflow fan technology program is discussed. Technology efforts in the basic discipline areas addressing the severe operating conditions associated with high-speed flight turbomachinery are reviewed. Included are examples of work in internal fluid mechanics, high-temperature materials, structural analysis, instrumentation and controls.

  19. First Annual High-Speed Research Workshop, part 4

    NASA Technical Reports Server (NTRS)

    Whitehead, Allen H., Jr. (Compiler)

    1992-01-01

    Papers presented at the First Annual High Speed Research Workshop held in Williamsburg, Viginia, on May 14-16, 1991 are presented. This NASA-sponsored workshop provided a national forum for presenting and discussing important technology issues related to the definition of an economically viable and environmentally compatible High Speed Civil Transport. The sessions are developed around the technical components of NASA's Phase 1 High Speed Research Program which addresses the environmental issues of atmospheric emissions, community noise, and sonic boom. In particular, this part of the publication, Part 4, addresses high lift research and supersonic laminar flow control.

  20. Experimental ball bearing dynamics study. [by high speed photography

    NASA Technical Reports Server (NTRS)

    Signer, H. R.

    1973-01-01

    A photographic method was employed to record the kinematic performance of rolling elements in turbo machinery ball bearings. The 110 mm split inner ring test bearings had nominal contact angles of 26 deg and 34 deg. High speed films were taken at inner ring speeds of 4,000, 8,000 and 12,000 rpm and at thrust loads of 4,448 N and 22,240 N (1,000 and 5,000 lbs). The films were measured and this data reduced to obtain separator speed, ball speed and ball spin axis orientation.

  1. Review of High-Speed Fiber Optic Grating Sensors Systems

    SciTech Connect

    Udd, E; Benterou, J; May, C; Mihailov, S J; Lu, P

    2010-03-24

    Fiber grating sensors can be used to support a wide variety of high speed measurement applications. This includes measurements of vibrations on bridges, traffic monitoring on freeways, ultrasonic detection to support non-destructive tests on metal plates and providing details of detonation events. This paper provides a brief overview of some of the techniques that have been used to support high speed measurements using fiber grating sensors over frequency ranges from 10s of kHz, to MHZ and finally toward frequencies approaching the GHz regime. Very early in the development of fiber grating sensor systems it was realized that a high speed fiber grating sensor system could be realized by placing an optical filter that might be a fiber grating in front of a detector so that spectral changes in the reflection from a fiber grating were amplitude modulated. In principal the only limitation on this type of system involved the speed of the output detector which with the development of high speed communication links moved from the regime of 10s of MHz toward 10s of GHz. The earliest deployed systems involved civil structures including measurements of the strain fields on composite utility poles and missile bodies during break tests, bridges and freeways. This was followed by a series of developments that included high speed fiber grating sensors to support nondestructive testing via ultrasonic wave detection, high speed machining and monitoring ship hulls. Each of these applications involved monitoring mechanical motion of structures and thus interest was in speeds up to a few 10s of MHz. Most recently there has been interest in using fiber grating to monitor the very high speed events such as detonations and this has led to utilization of fiber gratings that are consumed during an event that may require detection speeds of hundreds of MHz and in the future multiple GHz.

  2. Used fuel rail shock and vibration testing options analysis

    SciTech Connect

    Ross, Steven B.; Best, Ralph E.; Klymyshyn, Nicholas A.; Jensen, Philip J.; Maheras, Steven J.

    2014-09-25

    ) on the surrogate fuel assemblies, cask and cradle structures, and the railcar so that forces and deflections that would result in the greatest potential for damage to high burnup and long-cooled UNF can be determined. For purposes of this report we consider testing on controlled track when we have control of the track and speed to facilitate modeling.

  3. High-speed LWR transients simulation for optimizing emergency response

    SciTech Connect

    Wulff, W.; Cheng, H.S.; Lekach, S.V.; Mallen, A.N.; Stritar, A.

    1984-11-19

    The purpose of computer-assisted emergency response in nuclear power plants, and the requirements for achieving such a response, are presented. An important requirement is the attainment of realistic high-speed plant simulations at the reactor site. Currently pursued development programs for plant simulations are reviewed. Five modeling principles are established and a criterion is presented for selecting numerical procedures and efficient computer hardware to achieve high-speed simulations. A newly developed technology for high-speed power plant simulation is described and results are presented. It is shown that simulation speeds ten times greater than real-time process-speeds are possible, and that plant instrumentation can be made part of the computational loop in a small, on-site minicomputer. Additional technical issues are presented which must still be resolved before the newly developed technology can be implemented in a nuclear power plant.

  4. The time domain moving Green function of a railway track and its application to wheel-rail interactions

    NASA Astrophysics Data System (ADS)

    Sheng, X.; Xiao, X.; Zhang, S.

    2016-09-01

    When dealing with wheel-rail interactions for a high-speed train using the time domain Green function of a railway track, it would be more reasonable to use the moving Green function associated with a reference frame moving with the train, since observed from this frame wheel/rail forces are stationary. In this paper, the time domain moving Green function of a railway track as an infinitely long periodic structure is defined, derived, discussed and applied. The moving Green function is defined as the Fourier transform, from the load frequency domain to the time domain, of the response of the rail due to a moving harmonic load. The response of the rail due to a moving harmonic load is calculated using the Fourier transform-based method. A relationship is established between the moving Green function and the conventional impulse response function of the track. Properties of the moving Green function are then explored which can largely simplify the calculation of the Green function. And finally, the moving Green function is applied to deal with interactions between wheels and a track with or without rail dampers, allowing non-linearity in wheel-rail contact and demonstrating the effect of the rail dampers.

  5. The Lag Model Applied to High Speed Flows

    NASA Technical Reports Server (NTRS)

    Olsen, Michael E.; Coakley, Thomas J.; Lillard, Randolph P.

    2005-01-01

    The Lag model has shown great promise in prediction of low speed and transonic separations. The predictions of the model, along with other models (Spalart-Allmaras and Menter SST) are assessed for various high speed flowfields. In addition to skin friction and separation predictions, the prediction of heat transfer are compared among these models, and some fundamental building block flowfields, are investigated.

  6. Incorporating YBCO Coated Conductors in High-speed Superconducting Generators

    DTIC Science & Technology

    2008-07-01

    4.0 kW/lb (8.82 kW/kg). The machine configuration chosen by GE for design was a homopolar inductor alternator (HIA) which locates the...extremely severe ac loss environment. Even if this is ultimately impossible for high speed generators, it may not preclude lower speed motors and

  7. Application Of High Speed Photography In Science And Technology

    NASA Astrophysics Data System (ADS)

    Wu Ji-Zong, Wu; Yu-Ju, Lin

    1983-03-01

    The service works in high-speed photography carried out by the Department of Precision Instruments, Tianjin University are described in this paper. A compensation type high-speed camera was used in these works. The photographic methods adopted and better results achieved in the studies of several technical fields, such as velocity field of flow of overflow surface of high dam, combustion process of internal combustion engine, metal cutting, electrical are welding, experiment of piling of steel tube piles for supporting the marine platforms and characteristics of motion of wrist watch escape mechanism and so on are illustrated in more detail. As the extension of human visual organs and for increasing the abi-lities of observing and studying the high-speed processes, high-speed photography plays a very important role. In order to promote the application and development on high-speed photography, we have carried out the consultative and service works inside and outside Tianjin Uni-versity. The Pentazet 35 compensation type high-speed camera, made in East Germany, was used to record the high-speed events in various kinds of technical investigations and necessary results have been ob-tained. 1. Measurement of flow velocity on the overflow surface of high dam. In the design of a key water control project with high head, it is extremely necessary to determinate various characteristics of flow velocity field on the overflow surface of high dam. Since the water flow on the surface of high overflow dam possesses the features of large flow velocity and shallow water depth, therefore it is difficult to use the conventional current meters such as pilot tube, miniature cur-rent meter or electrical measuring methods of non-electrical quantities for studying this problem. Adopting the high-speed photographic method to study analogously the characteristics of flow velocity field on the overflow surface of high dam is a kind of new measuring method. People

  8. Design of high speed LVDS transceiver ICs

    NASA Astrophysics Data System (ADS)

    Jian, Xu; Zhigong, Wang; Xiaokang, Niu

    2010-07-01

    The design of low-power LVDS (low voltage differential signaling) transceiver ICs is presented. The LVDS transmitter integrates a common-mode feedback control on chip, while a specially designed pre-charge circuit is proposed to improve the speed of the circuit, making the highest data rate up to 622 Mb/s. For the LVDS receiver design, the performance degradation issues are solved when handling the large input common mode voltages of the conventional LVDS receivers. In addition, the LVDS receiver also supports the failsafe function. The transceiver chips were verified with the CSMC 0.5-μm CMOS process. The measured results showed that, for the LVDS transmitter with the pre-charge technique proposed, the maximum data rate is higher than 622 Mb/s. The power consumption is 6 mA with a 5-V power supply. The LVDS receiver can work properly with a larger input common mode voltage (0.1-2.4 V) but a differential input voltage as low as 100 mV. The power consumption is only 1.2 mA with a 5-V supply at the highest data rate of 400 Mb/s. The chip set meets the TIA/EIA-644-A standards and shows its potential prospects in LVDS transmission systems.

  9. Performance analysis of pseudo 4-phase dual-rail asynchronous protocol

    NASA Astrophysics Data System (ADS)

    Santhi, M.; Sarangan, Siddharth; Murali, K.; Lakshminarayanan, G.

    2012-08-01

    This article presents the performance analysis of novel pseudo 4-phase dual-rail protocol with self-reset and multiple-reset logic for high speed asynchronous applications. The self-reset logic eliminates the need for separate empty phase and hence reduces the number of transitions at the input and the output. The multiple-reset logic reduces the reset phase and hence increases the throughput. The performance of the pseudo 4-phase dual-rail protocol is compared with the existing 4-phase dual-rail protocol by implementing 8-bit and 16-bit asynchronously pipelined carry look ahead adders (CLA) in 0.35 µm technology. The time period decreases up to 32.58% and 35.93% respectively, the reset phase reduces up to 66.39% and 76.18%, respectively, and the operating frequency increases up to 48.4% and 56.2%, respectively, for 8- and 16-bit CLA adders with the pseudo 4-phase dual-rail protocol compared to the conventional 4-phase dual-rail protocol at the cost of increase in area of 8.8% and 3.3%, respectively. The delay-power product in ns-mW of the 8- and 16-bit CLAs is reduced at the maximum of 11.29% and 23.74%, respectively, with the pseudo 4-phase dual-rail protocol compared to the conventional 4-phase dual-rail protocol. The pseudo 4-phase dual-rail protocol is suitable for interfacing with synchronous environments.

  10. High Speed Measurements using Fiber-optic Bragg Grating Sensors

    SciTech Connect

    Benterou, J J; May, C A; Udd, E; Mihailov, S J; Lu, P

    2011-03-26

    Fiber grating sensors may be used to monitor high-speed events that include catastrophic failure of structures, ultrasonic testing and detonations. This paper provides insights into the utility of fiber grating sensors to measure structural changes under extreme conditions. An emphasis is placed on situations where there is a structural discontinuity. Embedded chirped fiber Bragg grating (CFBG) sensors can track the very high-speed progress of detonation waves (6-9 km/sec) inside energetic materials. This paper discusses diagnostic instrumentation and analysis techniques used to measure these high-speed events.

  11. Trend on High-speed Power Line Communication Technology

    NASA Astrophysics Data System (ADS)

    Ogawa, Osamu

    High-speed power line communication (PLC) is useful technology to easily build the communication networks, because construction of new infrastructure is not necessary. In Europe and America, PLC has been used for broadband networks since the beginning of 21th century. In Japan, high-speed PLC was deregulated only indoor usage in 2006. Afterward it has been widely used for home area network, LAN in hotels and school buildings and so on. And recently, PLC is greatly concerned as communication technology for smart grid network. In this paper, the author surveys the high-speed PLC technology and its current status.

  12. High-speed AFM of human chromosomes in liquid

    NASA Astrophysics Data System (ADS)

    Picco, L. M.; Dunton, P. G.; Ulcinas, A.; Engledew, D. J.; Hoshi, O.; Ushiki, T.; Miles, M. J.

    2008-09-01

    Further developments of the previously reported high-speed contact-mode AFM are described. The technique is applied to the imaging of human chromosomes at video rate both in air and in water. These are the largest structures to have been imaged with high-speed AFM and the first imaging in liquid to be reported. A possible mechanism that allows such high-speed contact-mode imaging without significant damage to the sample is discussed in the context of the velocity dependence of the measured lateral force on the AFM tip.

  13. High speed measurements using fiber-optic Bragg gratings

    NASA Astrophysics Data System (ADS)

    Benterou, Jerry; May, Chadd; Udd, Eric; Mihailov, Stephen J.; Lu, Ping

    2011-06-01

    Fiber grating sensors may be used to monitor high-speed events that include catastrophic failure of structures, ultrasonic testing and detonations. This paper provides insights into the utility of fiber grating sensors to measure structural changes under extreme conditions. An emphasis is placed on situations where there is a structural discontinuity. Embedded chirped fiber Bragg grating (CFBG) sensors can track the very high-speed progress of detonation waves (6-9 km/sec) inside energetic materials. This paper discusses diagnostic instrumentation and analysis techniques used to measure these high-speed events.

  14. First Annual High-Speed Research Workshop, part 3

    NASA Technical Reports Server (NTRS)

    Whitehead, Allen H., Jr. (Compiler)

    1992-01-01

    The First High-Speed Research (HSR) Workshop was hosted by NASA LaRC and was held 14-16 May 1991, in Williamsburg, Virginia. The purpose of the workshop was to provide a national forum for the government, industry, and university participants to present and discuss important technology issues related to the development of a commercially viable, environmentally compatible, U.S. High-Speed Civil Transport. The workshop sessions are organized around the major task elements in NASA's Phase 1 High-Speed Research Program which basically addresses the environmental issues of atmospheric emissions, community noise, and sonic boom.

  15. High-speed digital project, HSD test capability

    NASA Astrophysics Data System (ADS)

    Markley, R. E.; Elarton, J. L.; Allen, C. T.

    1994-04-01

    Establishing a high-speed digital (HSD) test capability for the Digital Waveform Synthesizer (DWS) multichip module (MCM) has required the development of several areas: a detailed test plan for the MCM; design, fabrication and proving of the high-speed test console; and the specification, design, and development of the high-speed test and environmental conditioning interface to the DWS. These development activities have been successfully completed at the Allied Signal Inc., Kansas City Division (KCD), and the test capability described herein is currently supporting DWS MCM testing and can be adapted to similar HSD module testing.

  16. Rat muscle blood flows during high-speed locomotion

    SciTech Connect

    Armstrong, R.B.; Laughlin, M.H.

    1985-10-01

    We previously studied blood flow distribution within and among rat muscles as a function of speed from walking (15 m/min) through galloping (75 m/min) on a motor-driven treadmill. The results showed that muscle blood flows continued to increase as a function of speed through 75 m/min. The purpose of the present study was to have rats run up to maximal treadmill speeds to determine if blood flows in the muscles reach a plateau as a function of running speed over the animals normal range of locomotory speeds. Muscle blood flows were measured with radiolabeled microspheres at 1 min of running at 75, 90, and 105 m/min in male Sprague-Dawley rats. The data indicate that even at these relatively high treadmill speeds there was still no clear evidence of a plateau in blood flow in most of the hindlimb muscles. Flows in most muscles continued to increase as a function of speed. These observed patterns of blood flow vs. running speed may have resulted from the rigorous selection of rats that were capable of performing the high-intensity exercise and thus only be representative of a highly specific population of animals. On the other hand, the data could be interpreted to indicate that the cardiovascular potential during exercise is considerably higher in laboratory rats than has normally been assumed and that inadequate blood flow delivery to the muscles does not serve as a major limitation to their locomotory performance.

  17. High speed high dynamic range high accuracy measurement system

    SciTech Connect

    Deibele, Craig E.; Curry, Douglas E.; Dickson, Richard W.; Xie, Zaipeng

    2016-11-29

    A measuring system includes an input that emulates a bandpass filter with no signal reflections. A directional coupler connected to the input passes the filtered input to electrically isolated measuring circuits. Each of the measuring circuits includes an amplifier that amplifies the signal through logarithmic functions. The output of the measuring system is an accurate high dynamic range measurement.

  18. MEMS-based high speed scanning probe microscopy.

    PubMed

    Disseldorp, E C M; Tabak, F C; Katan, A J; Hesselberth, M B S; Oosterkamp, T H; Frenken, J W M; van Spengen, W M

    2010-04-01

    The high speed performance of a scanning probe microscope (SPM) is improved if a microelectromechanical systems (MEMS) device is employed for the out-of-plane scanning motion. We have carried out experiments with MEMS high-speed z-scanners (189 kHz fundamental resonance frequency) in both atomic force microscope and scanning tunneling microscope modes. The experiments show that with the current MEMS z-scanner, lateral tip speeds of 5 mm/s can be achieved with full feedback on surfaces with significant roughness. The improvement in scan speed, obtained with MEMS scanners, increases the possibilities for SPM observations of dynamic processes. Even higher speed MEMS scanners with fundamental resonance frequencies in excess of a megahertz are currently under development.

  19. Highly Reliable, High-Speed, Unidirectional Serial Data Links

    NASA Technical Reports Server (NTRS)

    Cole, Robert M.; Bishop, Jamie

    2005-01-01

    Highly reliable, high-speed, unidirectional serial data-communication subsystems have been proposed to be installed in an upgrade of the computing systems aboard the space shuttles. The basic design concept of these serial data links is also adaptable to terrestrial use in applications in which there are requirements for highly reliable serial data communications. The hardware and software aspects of the architecture of the data links are dictated largely by a requirement, in the original space-shuttle application, for one computer to monitor the memory transactions and memory contents of other computers in real time with high reliability and without reliance on requests for retransmission. To minimize weight while affording a capability to transfer data at a required rate of 2.56 x 10(exp 8) bits per second, it was decided that the links would be serial ones of the fiber-channel type. [Fiber channel denotes a type of serial computer bus that is used to connect a computer (usually a supercomputer) with a high-speed data storage device. Depending on the specific application, the physical connection between the transmitter and receiver could be made via an optical fiber or a twisted pair of wires.] Heretofore, fiber-channel links have ordinarily been bidirectional and have operated under protocols that provide for receiving stations to detect errors and request retransmission when necessary. In the present case, the time taken by processing to request retransmission would conflict with the requirement for real-time transfer of data. To ensure reliability without retransmission, a link according to the proposal would utilize a modified version of the normal fiberchannel character set in conjunction with forward error correction by means of a Reed-Solomon code (see figure). The Reed-Solomon encoding and decoding and the translations between the normal and modified character sets would be effected by logic circuitry external to the fiber-channel transmitter and receiver

  20. FPGA Flash Memory High Speed Data Acquisition

    NASA Technical Reports Server (NTRS)

    Gonzalez, April

    2013-01-01

    The purpose of this research is to design and implement a VHDL ONFI Controller module for a Modular Instrumentation System. The goal of the Modular Instrumentation System will be to have a low power device that will store data and send the data at a low speed to a processor. The benefit of such a system will give an advantage over other purchased binary IP due to the capability of allowing NASA to re-use and modify the memory controller module. To accomplish the performance criteria of a low power system, an in house auxiliary board (Flash/ADC board), FPGA development kit, debug board, and modular instrumentation board will be jointly used for the data acquisition. The Flash/ADC board contains four, 1 MSPS, input channel signals and an Open NAND Flash memory module with an analog to digital converter. The ADC, data bits, and control line signals from the board are sent to an Microsemi/Actel FPGA development kit for VHDL programming of the flash memory WRITE, READ, READ STATUS, ERASE, and RESET operation waveforms using Libero software. The debug board will be used for verification of the analog input signal and be able to communicate via serial interface with the module instrumentation. The scope of the new controller module was to find and develop an ONFI controller with the debug board layout designed and completed for manufacture. Successful flash memory operation waveform test routines were completed, simulated, and tested to work on the FPGA board. Through connection of the Flash/ADC board with the FPGA, it was found that the device specifications were not being meet with Vdd reaching half of its voltage. Further testing showed that it was the manufactured Flash/ADC board that contained a misalignment with the ONFI memory module traces. The errors proved to be too great to fix in the time limit set for the project.

  1. High-speed digital signal normalization for feature identification

    NASA Technical Reports Server (NTRS)

    Ortiz, J. A.; Meredith, B. D.

    1983-01-01

    A design approach for high speed normalization of digital signals was developed. A reciprocal look up table technique is employed, where a digital value is mapped to its reciprocal via a high speed memory. This reciprocal is then multiplied with an input signal to obtain the normalized result. Normalization improves considerably the accuracy of certain feature identification algorithms. By using the concept of pipelining the multispectral sensor data processing rate is limited only by the speed of the multiplier. The breadboard system was found to operate at an execution rate of five million normalizations per second. This design features high precision, a reduced hardware complexity, high flexibility, and expandability which are very important considerations for spaceborne applications. It also accomplishes a high speed normalization rate essential for real time data processing.

  2. Effects of high-speed power training on muscle performance and braking speed in older adults.

    PubMed

    Sayers, Stephen P; Gibson, Kyle

    2012-01-01

    We examined whether high-speed power training (HSPT) improved muscle performance and braking speed using a driving simulator. 72 older adults (22 m, 50 f; age = 70.6 ± 7.3 yrs) were randomized to HSPT at 40% one-repetition maximum (1RM) (HSPT: n = 25; 3 sets of 12-14 repetitions), slow-speed strength training at 80%1RM (SSST: n = 25; 3 sets of 8-10 repetitions), or control (CON: n = 22; stretching) 3 times/week for 12 weeks. Leg press and knee extension peak power, peak power velocity, peak power force/torque, and braking speed were obtained at baseline and 12 weeks. HSPT increased peak power and peak power velocity across a range of external resistances (40-90% 1RM; P < 0.05) and improved braking speed (P < 0.05). Work was similar between groups, but perceived exertion was lower in HSPT (P < 0.05). Thus, the less strenuous HSPT exerted a broader training effect and improved braking speed compared to SSST.

  3. Driver assist behaviors for high-speed small UGVs

    NASA Astrophysics Data System (ADS)

    Yamauchi, Brian

    2011-05-01

    Currently deployed small UGVs operate at speeds up to around 6 mph and have proven their usefulness in explosives ordnance disposal (EOD) missions. As part of the TARDEC-funded Stingray Project, iRobot is investigating techniques to increase the speed of small UGVs so they can be useful in a wider range of missions, such as high-speed reconnaissance and infantry assault missions. We have developed a prototype Stingray PackBot, using wheels rather than tracks, that is capable of traveling at speeds up to 18 mph. A key issue when traveling at such speeds is how to maintain stability during sharp turns and over rough terrain. We are developing driver assist behaviors that will provide dynamic stability control for high-speed small UGVs using techniques such as dynamic weight shifting to limit oversteer and understeer. These driver assist behaviors will enable operators to use future high-speed small UGVs in high optempo infantry missions and keep warfighters out of harm's way.

  4. High-speed seal and bearing test facility

    NASA Technical Reports Server (NTRS)

    Panos, Jean B.

    1994-01-01

    The following topics are discussed in this viewgraph presentation: high speed seal/bearing rig background, project status, facility features, test rig capabilities, EMD testing advantages, and future opportunities.

  5. Design of high speed camera based on CMOS technology

    NASA Astrophysics Data System (ADS)

    Park, Sei-Hun; An, Jun-Sick; Oh, Tae-Seok; Kim, Il-Hwan

    2007-12-01

    The capacity of a high speed camera in taking high speed images has been evaluated using CMOS image sensors. There are 2 types of image sensors, namely, CCD and CMOS sensors. CMOS sensor consumes less power than CCD sensor and can take images more rapidly. High speed camera with built-in CMOS sensor is widely used in vehicle crash tests and airbag controls, golf training aids, and in bullet direction measurement in the military. The High Speed Camera System made in this study has the following components: CMOS image sensor that can take about 500 frames per second at a resolution of 1280*1024; FPGA and DDR2 memory that control the image sensor and save images; Camera Link Module that transmits saved data to PC; and RS-422 communication function that enables control of the camera from a PC.

  6. High speed testing of the hollow roller bearing

    NASA Astrophysics Data System (ADS)

    Bowen, W. L.; Murphy, T. W., Jr.

    1980-08-01

    This bearing with its preloaded, hollow rollers has the qualities required for high speed operation. Roller hollowness improves cooling ability and its lighter weight reduces the centrifugal force against the raceway. Preloading between inner and outer races for 360 deg insures good roller guidance and minimizes roller skidding. However, the problems of operating a full complement of rollers at very high speeds were unknown. Also, limitations caused by roller bending fatigue needed investigation. To answer these questions, a high speed test machine was constructed and a hollow roller test bearing was designed for operation at 3 million DN. This paper describes the construction of a high speed test cell and subsequent testing of a full complement, preloaded, 115 mm hollow roller bearing. Testing culminated in a successful endurance test of 1000 hours at 26,100 RPM (3 million DN). The results verified several advantages regarding roller stability and antiskidding qualities as well as demonstrating a unique fail-safe condition.

  7. Discharge characteristics of a high speed fuel injection system

    NASA Technical Reports Server (NTRS)

    Matthews, Robertson

    1925-01-01

    Discussed here are some discharge characteristics of a fuel injection system intended primarily for high speed service. The system consisted of a cam actuated fuel pump, a spring loaded automatic injection valve, and a connecting tube.

  8. The High Speed Photometer for the Space Telescope

    NASA Technical Reports Server (NTRS)

    Bless, R. C.

    1982-01-01

    An overview of the high speed photometer (HSP), its optics and detectors, its electronics, its mechanical structure, and some observational considerations are presented. The capabilities and limitations of the HSP are outlined.

  9. The flight of an autogiro at high speed

    NASA Technical Reports Server (NTRS)

    Bennett, J A J

    1933-01-01

    This report presents a method for computing the flight performance of an autogiro at high speed, the velocity component along the blades being accounted for by calculation of the profile drag and the equation for zero torque.

  10. High-speed vertical cavity surface emitting lasers

    SciTech Connect

    Lear, K.L.; Ochiai, M.; Hietala, V.M.

    1997-03-01

    High speed modulation and pulsing are reported for oxide-confined vertical cavity surface emitting laser diodes (VCSELs) with inverted doping and proton implantation to reduce the extrinsic limitations.

  11. A Case Study of the High-speed Train Crash Outside Santiago de Compostela, Galicia, Spain.

    PubMed

    Forsberg, Rebecca; Vázquez, José Antonio Iglesias

    2016-04-01

    The worldwide use of rail transport has increased, and the train speeds are escalating. Concurrently, the number of train disasters has been amplified globally. Consequently, railway safety has become an important issue for the future. High-velocity crashes increase the risk for injuries and mortality; nevertheless, there are relatively few studies on high-speed train crashes and the influencing factors on travelers' injuries occurring in the crash phase. The aim of this study was to investigate the fatal and non-fatal injuries and the main interacting factors that contributed to the injury process in the crash phase of the 2013 high-velocity train crash that occurred at Angrois, outside Santiago de Compostela, Spain. Hospital records (n=157) of all the injured who were admitted to the six hospitals in the region were reviewed and compiled by descriptive statistics. The instant fatalities (n=63) were collected on site. Influencing crash factors were observed on the crash site, by carriage inspections, and by reviewing official reports concerning the approximated train speed. The main interacting factors that contributed in the injury process in the crash phase were, among other things, the train speed, the design of the concrete structure of the curve, the robustness of the carriage exterior, and the interior environment of the carriages. Of the 222 people on board (218 passengers and four crew), 99% (n=220) were fatally or non-fatally injured in the crash. Thirty-three percent (n=72) suffered fatal injuries, of which 88% (n=63) died at the crash site and 13% (n=9) at the hospital. Twenty-one percent (n=32) of those admitted to hospital suffered multi-trauma (ie, extensive, severe, and/or critical injuries). The head, face, and neck sustained 42% (n=123) of the injuries followed by the trunk (chest, abdomen, and pelvis; n=92; 32%). Fractures were the most frequent (n=200; 69%) injury. A mass-casualty incident with an extensive amount of fatal, severe, and critical

  12. High Speed Multiplex Bus Protocol Study.

    DTIC Science & Technology

    1980-06-15

    Transaction 42-45 3.3.4.1-1 High Level Bus State Transition Diagram; BC-RT 48 Poll or Transaction Request 3.3.4.1-2 Response Time Out Interval Measurement 49...61 3.4-2 General Message Types 62 3.4.3-1 High Level BC State Transition Diagram - BC-RT 64 Transaction Request 3.4.3-2 High Level RT State Transition...the data base for each bus unit contains the current state of that bus unit with respect to ongoing bus communications. The bus control data base

  13. Explosive-driven, high speed, arcless switch

    DOEpatents

    Skogmo, P.J.; Tucker, T.J.

    1987-07-14

    An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed. 7 figs.

  14. Explosive-driven, high speed, arcless switch

    DOEpatents

    Skogmo, P.J.; Tucker, T.J.

    1986-05-02

    An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed.

  15. Explosive-driven, high speed, arcless switch

    DOEpatents

    Skogmo, Phillip J.; Tucker, Tillman J.

    1987-01-01

    An explosive-actuated, fast-acting arcless switch contains a highly conductive foil to carry high currents positioned adjacent a dielectric surface within a casing. At one side of the foil opposite the dielectric surface is an explosive which, when detonated, drives the conductive foil against the dielectric surface. A pattern of grooves in the dielectric surface ruptures the foil to establish a rupture path having a pattern corresponding to the pattern of the grooves. The impedance of the ruptured foil is greater than that of the original foil to divert high current to a load. Planar and cylindrical embodiments of the switch are disclosed.

  16. Technology needs for high-speed rotorcraft, volume 1

    NASA Technical Reports Server (NTRS)

    Wilkerson, J. B.; Schneider, J. J.; Bartie, K. M.

    1991-01-01

    High-speed rotorcraft concepts and the technology needed to extend rotorcraft cruise speeds up to 450 knots (while retaining the helicopter attributes of low downwash velocities) were identified. Task I identified 20 concepts with high-speed potential. These concepts were qualitatively evaluated to determine the five most promising ones. These five concepts were designed with optimum wing loading and disk loading to a common NASA-defined military transport mission. The optimum designs were quantitatively compared against 11 key criteria and ranked accordingly. The two highest ranking concepts were selected for the further study.

  17. Reduced Order Modeling For High Speed Flows with Moving Shocks

    DTIC Science & Technology

    2001-12-03

    use of Proper Orthogonal Decomposition ( POD ) for reduced order modeling (ROM)of fluid problems is extended to high-speed compressible fluid flows. The...challenge in using POD for high-speed flows is presented by the presence of moving discontinuities in the flow field. To ovecome these difficulties...difficulty. The accuracy and order reduction of the domain decomposition POD /ROM approach is quantified for each application. ROMs with as large as three

  18. High speed data transmission at the Superconducting Super Collider

    SciTech Connect

    Leskovar, B. )

    1991-04-01

    In this paper high speed data transmission using fiber optics in the data acquisition system of the Superconducting Super Collider has been investigated. Emphasis is placed on the high speed data transmission system overview, the local data network and on subassemblies, such as optical transmitters and receivers. Also, the performance of candidate subassemblies having a low power dissipation for the data acquisition system is discussed.

  19. Impact of a Diesel High Pressure Common Rail Fuel System and Onboard Vehicle Storage on B20 Biodiesel Blend Stability

    SciTech Connect

    Christensen, Earl; McCormick, Robert L.; Sigelko, Jenny; Johnson, Stuart; Zickmann, Stefan; Lopes, Shailesh; Gault, Roger; Slade, David

    2016-04-01

    Adoption of high-pressure common-rail (HPCR) fuel systems, which subject diesel fuels to higher temperatures and pressures, has brought into question the efficacy of ASTM International specifications for biodiesel and biodiesel blend oxidation stability, as well as the lack of any stability parameter for diesel fuel. A controlled experiment was developed to investigate the impact of a light-duty diesel HPCR fuel system on the stability of 20% biodiesel (B20) blends under conditions of intermittent use and long-term storage in a relatively hot and dry climate. B20 samples with Rancimat induction periods (IPs) near the current 6.0-hour minimum specification (6.5 hr) and roughly double the ASTM specification (13.5 hr) were prepared from a conventional diesel and a highly unsaturated biodiesel. Four 2011 model year Volkswagen Passats equipped with HPCR fuel injection systems were utilized: one on B0, two on B20-6.5 hr, and one on B20-13.5 hr. Each vehicle was operated over a one-hour drive cycle in a hot running loss test cell to initially stress the fuel. The cars were then kept at Volkswagen's Arizona Proving Ground for two (35 degrees C average daily maximum) to six months (26 degrees C average daily maximum). The fuel was then stressed again by running a portion of the one-hour dynamometer drive cycle (limited by the amount of fuel in the tank). Fuel rail and fuel tank samples were analyzed for IP, acid number, peroxide content, polymer content, and ester profile. The HPCR fuel pumps were removed, dismantled, and inspected for deposits or abnormal wear. Analysis of fuels collected during initial dynamometer tests showed no impact of exposure to HPCR conditions. Long-term storage with intermittent use showed that IP remained above 3 hours, acid number below 0.3 mg KOH/g, peroxides low, no change in ester profile, and no production of polymers. Final dynamometer tests produced only small changes in fuel properties. Inspection of the HPCR fuel pumps revealed no

  20. High Speed Computing, LANs, and WAMs

    NASA Technical Reports Server (NTRS)

    Bergman, Larry A.; Monacos, Steve

    1994-01-01

    Optical fiber networks may one day offer potential capacities exceeding 10 terabits/sec. This paper describes present gigabit network techniques for distributed computing as illustrated by the CASA gigabit testbed, and then explores future all-optic network architectures that offer increased capacity, more optimized level of service for a given application, high fault tolerance, and dynamic reconfigurability.

  1. High Speed Computing, LANs, and WAMs

    NASA Technical Reports Server (NTRS)

    Bergman, Larry A.; Monacos, Steve

    1994-01-01

    Optical fiber networks may one day offer potential capacities exceeding 10 terabits/sec. This paper describes present gigabit network techniques for distributed computing as illustrated by the CASA gigabit testbed, and then explores future all-optic network architectures that offer increased capacity, more optimized level of service for a given application, high fault tolerance, and dynamic reconfigurability.

  2. High-speed photography of high-resolution moire patterns

    NASA Astrophysics Data System (ADS)

    Whitworth, Martin B.; Huntley, Jonathan M.; Field, John E.

    1991-04-01

    The techniques of high resolution moire photography and high speed photography have been combined to allow measurement of the in-plane components of a transient displacement field with microsecond time resolution. Specimen gratings are prepared as casts in a thin layer of epoxy resin on the surface of a specimen. These are illuminated with a flash tube and imaged onto a reference grating with a specially modified camera lens, which incorporates a slotted mask in the aperture plane. For specimen gratings of 75 lines mm1, this selects the +1 and -1 order diffracted beams, thus doubling the effective grating frequency to 150 lines mm1. The resulting real-time moire fringes are recorded with a Hadland 792 image converter camera (Imacon) at an inter-frame time of 2-5ts. The images are digitised and an automatic fringe analysis technique based on the 2-D Fourier transform method is used to extract the displacement information. The technique is illustrated by the results of an investigation into the transient deformation of composite disc specimens, impacted with rectangular metal sliders fired from a gas gun.

  3. A new design for a high speed spindle

    SciTech Connect

    Weck, M.; Fischer, S.; Holster, P.; Carlisle, K.; Chen, Y.

    1996-12-31

    Precision grinding and micromachining both impose high demands on the machine behavior, since the achievable workpiece accuracy is determined not only by the technological parameters but also by the characteristics of the applicated machine components. Ultraprecision surface quality and the mechanical fabrication of structures in the micron range can only be achieved by using machine tools which have appropriate spindles. Structures cannot be manufactured using spindle types of which the radial error motion is greater than the level of contour accuracy or surface roughness required. In addition, the spindle speed is an important value. Not only a certain cutting speed is needed from the technological point of view, but also the machining time required for microstructuring surfaces is reduced by deploying a high frequency spindle, thereby increasing the economic efficiency of the technique. Hence, the main purpose of the project was to develop a high speed spindle with properties concerning accuracy, speed and stiffness beyond commercially available ones.

  4. Three-dimensional dynamic analyses of track-embankment-ground system subjected to high speed train loads.

    PubMed

    Fu, Qiang; Zheng, Changjie

    2014-01-01

    A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed.

  5. Three-Dimensional Dynamic Analyses of Track-Embankment-Ground System Subjected to High Speed Train Loads

    PubMed Central

    2014-01-01

    A three-dimensional finite element model was developed to investigate dynamic response of track-embankment-ground system subjected to moving loads caused by high speed trains. The track-embankment-ground systems such as the sleepers, the ballast, the embankment, and the ground are represented by 8-noded solid elements. The infinite elements are used to represent the infinite boundary condition to absorb vibration waves induced by the passing of train load at the boundary. The loads were applied on the rails directly to simulate the real moving loads of trains. The effects of train speed on dynamic response of the system are considered. The effect of material parameters, especially the modulus changes of ballast and embankment, is taken into account to demonstrate the effectiveness of strengthening the ballast, embankment, and ground for mitigating system vibration in detail. The numerical results show that the model is reliable for predicting the amplitude of vibrations produced in the track-embankment-ground system by high-speed trains. Stiffening of fill under the embankment can reduce the vibration level, on the other hand, it can be realized by installing a concrete slab under the embankment. The influence of axle load on the vibration of the system is obviously lower than that of train speed. PMID:24723838

  6. High speed cineradiography using electronic imaging

    NASA Astrophysics Data System (ADS)

    Lucero, J. P.; Fry, D. A.; Gaskill, W. E.; Henderson, R. L.; Crawford, T. R.; Carey, N. E.

    1992-12-01

    The Los Alamos National Laboratory has constructed and is now operating a cineradiography system for imaging and evaluation of ballistic interaction events at the 1200 meter range of the Terminal Effects Research and Analysis (TERA) Group at the New Mexico Institute of Mining and Technology. Cineradiography is part of a complete firing, tracking, and analysis system at the range. The cine system consists of flash x-ray sources illuminating a one-half meter by two meter fast phosphor screen which is viewed by gated-intensified high resolution still video cameras via turning mirrors. The entire system is armored to protect against events containing up to 13.5 kg of high explosive. Digital images are available for immediate display and processing. The system is capable of frame rates up to 10(exp 5)/sec for up to five total images.

  7. High-speed cineradiography using electronic imaging

    NASA Astrophysics Data System (ADS)

    Lucero, Jacob P.; Fry, David A.; Gaskill, William E.; Henderson, R. L.; Crawford, Ted R.; Carey, N. E.

    1993-01-01

    The Los Alamos National Laboratory has constructed and is now operating a cineradiography system for imaging and evaluation of ballistic interaction events at the 1200 meter range of the Terminal Effects Research and Analysis (TERA) Group at the New Mexico Institute of Mining and Technology. Cineradiography is part of a complete firing, tracking, and analysis system at the range. The cine system consists of flash x-ray sources illuminating a one-half meter by two meter fast phosphor screen which is viewed by gated-intensified high resolution still video cameras via turning mirrors. The entire system is armored to protect against events containing up to 13.5 kg of high explosive. Digital images are available for immediate display and processing. The system is capable of frame rates up to 105/sec for up to five total images.

  8. High-speed quantum networking by ship

    PubMed Central

    Devitt, Simon J.; Greentree, Andrew D.; Stephens, Ashley M.; Van Meter, Rodney

    2016-01-01

    Networked entanglement is an essential component for a plethora of quantum computation and communication protocols. Direct transmission of quantum signals over long distances is prevented by fibre attenuation and the no-cloning theorem, motivating the development of quantum repeaters, designed to purify entanglement, extending its range. Quantum repeaters have been demonstrated over short distances, but error-corrected, global repeater networks with high bandwidth require new technology. Here we show that error corrected quantum memories installed in cargo containers and carried by ship can provide a exible connection between local networks, enabling low-latency, high-fidelity quantum communication across global distances at higher bandwidths than previously proposed. With demonstrations of technology with sufficient fidelity to enable topological error-correction, implementation of the quantum memories is within reach, and bandwidth increases with improvements in fabrication. Our approach to quantum networking avoids technological restrictions of repeater deployment, providing an alternate path to a worldwide Quantum Internet. PMID:27805001

  9. High-speed quantum networking by ship.

    PubMed

    Devitt, Simon J; Greentree, Andrew D; Stephens, Ashley M; Van Meter, Rodney

    2016-11-02

    Networked entanglement is an essential component for a plethora of quantum computation and communication protocols. Direct transmission of quantum signals over long distances is prevented by fibre attenuation and the no-cloning theorem, motivating the development of quantum repeaters, designed to purify entanglement, extending its range. Quantum repeaters have been demonstrated over short distances, but error-corrected, global repeater networks with high bandwidth require new technology. Here we show that error corrected quantum memories installed in cargo containers and carried by ship can provide a exible connection between local networks, enabling low-latency, high-fidelity quantum communication across global distances at higher bandwidths than previously proposed. With demonstrations of technology with sufficient fidelity to enable topological error-correction, implementation of the quantum memories is within reach, and bandwidth increases with improvements in fabrication. Our approach to quantum networking avoids technological restrictions of repeater deployment, providing an alternate path to a worldwide Quantum Internet.

  10. High-speed quantum networking by ship

    NASA Astrophysics Data System (ADS)

    Devitt, Simon J.; Greentree, Andrew D.; Stephens, Ashley M.; van Meter, Rodney

    2016-11-01

    Networked entanglement is an essential component for a plethora of quantum computation and communication protocols. Direct transmission of quantum signals over long distances is prevented by fibre attenuation and the no-cloning theorem, motivating the development of quantum repeaters, designed to purify entanglement, extending its range. Quantum repeaters have been demonstrated over short distances, but error-corrected, global repeater networks with high bandwidth require new technology. Here we show that error corrected quantum memories installed in cargo containers and carried by ship can provide a exible connection between local networks, enabling low-latency, high-fidelity quantum communication across global distances at higher bandwidths than previously proposed. With demonstrations of technology with sufficient fidelity to enable topological error-correction, implementation of the quantum memories is within reach, and bandwidth increases with improvements in fabrication. Our approach to quantum networking avoids technological restrictions of repeater deployment, providing an alternate path to a worldwide Quantum Internet.

  11. UCSD/FRA non-contact ultrasonic guided-wave system for rail inspection: an update

    NASA Astrophysics Data System (ADS)

    Coccia, Stefano; Phillips, Robert; Nucera, Claudio; Bartoli, Ivan; Salamone, Salvatore; Lanza di Scalea, Francesco; Fateh, Mahmood; Carr, Gary

    2011-04-01

    The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail defect detection. A prototype has been designed and field tested with the support of Volpe National Transportation Systems Center and ENSCO, Inc. The goal of this project is to develop a rail defect detection system that provides (a) better defect detection reliability (including internal transverse head defects under shelling and vertical split head defects), and (b) higher inspection speed than achievable by current rail inspection systems. This effort is also in direct response to Safety Recommendations issued by the National Transportation Safety Board (NTSB) following the disastrous train derailments at Superior, WI in 1992 and Oneida, NY in 2007 among others. The UCSD prototype uses non-contact ultrasonic probing of the rail head (laser and air-coupled), ultrasonic guided waves, and a proprietary real-time statistical analysis algorithm that maximizes the sensitivity to defects while minimizing false positives. The current design allows potential inspection speeds up to 40 mph, although all field tests have been conducted up to 15 mph so far. This paper summarizes (a) the latest technology development test conducted at the rail defect farm of Herzog, Inc. in St Joseph, MO in June 2010, and (b) the completion of the new Rail Defect Farm facility at the UCSD Camp Elliott Field Station with partial in-kind donations from the Burlington Northern Santa Fe (BNSF) Railway.

  12. Niobium in Microalloyed Rail Steels

    NASA Astrophysics Data System (ADS)

    Ray, A.; Bhadeshia, H. K. D. H.

    Rails generally do not have a homogeneous austenite grain structure across their sections because the degree of plastic strain achieved during hot-rolling depends on location. Here we explore a philosophy in which niobium microalloying may be introduced in order to thermomechanically process the material so that pancaked and refined austenite grains may eventually be achieved in the critical regions of the rail. The essential principle in alloy design involves the avoidance of coarse niobium carbide precipitates in the regions of the steel that contain chemical segregation caused by non-equilibrium solidification. Both pearlitic and cementite-free bainitic rails have been studied. The work is of generic value to the design of high-carbon microalloyed steels.

  13. High-speed integrated electroabsorption modulators

    NASA Astrophysics Data System (ADS)

    Johnson, John E.; Morton, Paul A.; Park, Yong-Kwan; Ketelsen, Leonard J. P.; Grenko, J. A.; Miller, Thomas J.; Sputz, Sharon K.; Tanbun-Ek, Tawee; Vandenberg, J. M.; Yadvish, R. D.; Fullowan, Thomas R.; Sciortino, Paul F., Jr.; Sergent, A. M.; Tsang, Won-Tien

    1997-04-01

    The explosive growth in internet, multimedia and wireless traffic in recent years is rapidly exhausting capacity in public networks worldwide, forcing network service providers to aggressively install new lines and upgrade old ones. Fortunately, technological breakthroughs in the areas of erbium-doped fiber amplifiers (EDFA's), passive wavelength demultiplexers and low chirp sources have made all-optical dense wavelength-division multiplexed (WDM) systems a cost- effective way to utilize the vast bandwidth already available in the embedded fiber plant. WDM systems offer additional operational advantages, including high ultimate capacity, bit-rate transparency, flexible growth strategies, and the potential to use all-optical wavelength routing in future broadband network architectures. Commercial WDM systems operating at the OC-48 (2.5 Gbit/s) line rate are now available, and OC-192 (10 Gbit/s) terminal equipment which is under development will further enhance the capacity of these systems. One of the keys to viable WDM systems is the availability of inexpensive low-chirp optical transmitters. By taking advantage of photonic integrated circuit technology, it is possible to produce monolithically integrated DFB laser/EA modulators (EML's) with low chirp, low drive voltage and high extinction ratio, in a single compact package. In this talk we discuss the operating characteristics of these devices and their relationship to WDM system performance.

  14. Rail and Motor Outloading Capability Study, Fort Irwin, California,

    DTIC Science & Technology

    1978-05-01

    Designation of qualified persons to 213.135 Switches. supervie certain renewals and in- 213.137 Frogs . spect track. 213.139 Spring rail frogs . 213.9 Classes of...track: operating speed 213.141 Self-guarded frogs . limits. 213.143 Frog guard rails and guard faces; 213.11 Restoration or renewal of track gage...defective rail. B- ILimit oerating sped to 10 ni.p.h. over defective rail. C - Apply Joint 1,:trs holted only through the outermost holv. to defect within

  15. Coal-fueled high-speed diesel engine development

    SciTech Connect

    Kakwani, R. M.; Winsor, R. E.; Ryan, III, T. W.; Schwalb, J. A.; Wahiduzzaman, S.; Wilson, Jr., R. P.

    1991-11-01

    The objectives of this program are to study combustion feasibility by running Series 149 engine tests at high speeds with a fuel injection and combustion system designed for coal-water-slurry (CWS). The following criteria will be used to judge feasibility: (1) engine operation for sustained periods over the load range at speeds from 600 to 1900 rpm. The 149 engine for mine-haul trucks has a rated speed of 1900 rpm; (2) reasonable fuel economy and coal burnout rate; (3) reasonable cost of the engine design concept and CWS fuel compared to future oil prices.

  16. Faster Fluorescence Microscopy: Advances in High Speed Biological Imaging

    PubMed Central

    Winter, Peter W.; Shroff, Hari

    2014-01-01

    The past decade has seen explosive growth in new high speed imaging methods. These can broadly be classified as either point-scanning (which offer better depth penetration) or parallelized systems (which offer higher speed). We discuss each class generally, and cover specific advances in diffraction-limited microscopes (laser-scanning confocal, spinning-disk, and light-sheet) and super-resolution microscopes (single-molecule imaging, stimulated emission-depletion, and structured illumination). A theme of our review is that there is no free lunch: each technique has strengths and weaknesses, and an advance in speed usually comes at the expense of either spatial resolution or depth penetration. PMID:24815857

  17. Faster fluorescence microscopy: advances in high speed biological imaging.

    PubMed

    Winter, Peter W; Shroff, Hari

    2014-06-01

    The past decade has seen explosive growth in new high speed imaging methods. These can broadly be classified as either point-scanning (which offer better depth penetration) or parallelized systems (which offer higher speed). We discuss each class generally, and cover specific advances in diffraction-limited microscopes (laser-scanning confocal, spinning-disk, and light-sheet) and superresolution microscopes (single-molecule imaging, stimulated emission-depletion, and structured illumination). A theme of our review is that there is no free lunch: each technique has strengths and weaknesses, and an advance in speed usually comes at the expense of either spatial resolution or depth penetration.

  18. High-speed imaging system for observation of discharge phenomena

    NASA Astrophysics Data System (ADS)

    Tanabe, R.; Kusano, H.; Ito, Y.

    2008-11-01

    A thin metal electrode tip instantly changes its shape into a sphere or a needlelike shape in a single electrical discharge of high current. These changes occur within several hundred microseconds. To observe these high-speed phenomena in a single discharge, an imaging system using a high-speed video camera and a high repetition rate pulse laser was constructed. A nanosecond laser, the wavelength of which was 532 nm, was used as the illuminating source of a newly developed high-speed video camera, HPV-1. The time resolution of our system was determined by the laser pulse width and was about 80 nanoseconds. The system can take one hundred pictures at 16- or 64-microsecond intervals in a single discharge event. A band-pass filter at 532 nm was placed in front of the camera to block the emission of the discharge arc at other wavelengths. Therefore, clear images of the electrode were recorded even during the discharge. If the laser was not used, only images of plasma during discharge and thermal radiation from the electrode after discharge were observed. These results demonstrate that the combination of a high repetition rate and a short pulse laser with a high speed video camera provides a unique and powerful method for high speed imaging.

  19. Control structures for high speed processors

    NASA Technical Reports Server (NTRS)

    Maki, G. K.; Mankin, R.; Owsley, P. A.; Kim, G. M.

    1982-01-01

    A special processor was designed to function as a Reed Solomon decoder with throughput data rate in the Mhz range. This data rate is significantly greater than is possible with conventional digital architectures. To achieve this rate, the processor design includes sequential, pipelined, distributed, and parallel processing. The processor was designed using a high level language register transfer language. The RTL can be used to describe how the different processes are implemented by the hardware. One problem of special interest was the development of dependent processes which are analogous to software subroutines. For greater flexibility, the RTL control structure was implemented in ROM. The special purpose hardware required approximately 1000 SSI and MSI components. The data rate throughput is 2.5 megabits/second. This data rate is achieved through the use of pipelined and distributed processing. This data rate can be compared with 800 kilobits/second in a recently proposed very large scale integration design of a Reed Solomon encoder.

  20. Aeroacoustics of Turbulent High-Speed Jets

    NASA Technical Reports Server (NTRS)

    Rao, Ram Mohan; Lundgren, Thomas S.

    1996-01-01

    Aeroacoustic noise generation in a supersonic round jet is studied to understand in particular the effect of turbulence structure on the noise without numerically compromising the turbulence itself. This means that direct numerical simulations (DNS's) are needed. In order to use DNS at high enough Reynolds numbers to get sufficient turbulence structure we have decided to solve the temporal jet problem, using periodicity in the direction of the jet axis. Physically this means that turbulent structures in the jet are repeated in successive downstream cells instead of being gradually modified downstream into a jet plume. Therefore in order to answer some questions about the turbulence we will partially compromise the overall structure of the jet. The first section of chapter 1 describes some work on the linear stability of a supersonic round jet and the implications of this for the jet noise problem. In the second section we present preliminary work done using a TVD numerical scheme on a CM5. This work is only two-dimensional (plane) but shows very interesting results, including weak shock waves. However this is a nonviscous computation and the method resolves the shocks by adding extra numerical dissipation where the gradients are large. One wonders whether the extra dissipation would influence small turbulent structures like small intense vortices. The second chapter is an extensive discussion of preliminary numerical work using the spectral method to solve the compressible Navier-Stokes equations to study turbulent jet flows. The method uses Fourier expansions in the azimuthal and streamwise direction and a 1-D B-spline basis representation in the radial direction. The B-spline basis is locally supported and this ensures block diagonal matrix equations which are solved in O(N) steps. A very accurate highly resolved DNS of a turbulent jet flow is expected.

  1. SPH simulations of high-speed collisions

    NASA Astrophysics Data System (ADS)

    Rozehnal, Jakub; Broz, Miroslav

    2016-10-01

    Our work is devoted to a comparison of: i) asteroid-asteroid collisions occurring at lower velocities (about 5 km/s in the Main Belt), and ii) mutual collisions of asteroids and cometary nuclei usually occurring at significantly higher relative velocities (> 10 km/s).We focus on differences in the propagation of the shock wave, ejection of the fragments and possible differences in the resultingsize-frequency distributions of synthetic asteroid families. We also discuss scaling with respect to the "nominal" target diameter D = 100 km, projectile velocity 3-7 km/s, for which a number of simulations were done so far (Durda et al. 2007, Benavidez et al. 2012).In the latter case of asteroid-comet collisions, we simulate the impacts of brittle or pre-damaged impactors onto solid monolithic targets at high velocities, ranging from 10 to 15 km/s. The purpose of this numerical experiment is to better understand impact processes shaping the early Solar System, namely the primordial asteroid belt during during the (late) heavy bombardment (as a continuation of Broz et al. 2013).For all hydrodynamical simulations we use a smoothed-particle hydrodynamics method (SPH), namely the lagrangian SPH3D code (Benz & Asphaug 1994, 1995). The gravitational interactions between fragments (re-accumulation) is simulated with the Pkdgrav tree-code (Richardson et al. 2000).

  2. High Speed Imaging of Diesel Fuel Sprays

    NASA Astrophysics Data System (ADS)

    Jackson, Ja'kira; Bittle, Joshua

    2016-11-01

    Fuel sprays primarily serve as methods for fuel distribution, fuel/air mixing, and atomization. In this research, a constant pressure flow rig vessel is being tested at various pressures and temperatures using n-heptane. The experiment requires two imaging techniques: color Schlieren and Mie-scatter. Schlieren captures density gradients in a spray which includes both liquid and vapor phases while Mie-scatter is only sensitive to the liquid phase of the fuel spray. Essentially, studies are mainly focused on extracting the liquid boundary from the Schlieren to possibly eliminate the need for acquiring the Mie-Scatter technique. Four test conditions (combination of low and high pressure and temperatures) are used in the application to attempt to find the liquid boundary independent of the Mie-scatter technique. In this pursuit the following methods were used: a color threshold, a value threshold, and the time variation in color. All methods provided some indication of the liquid region but none were able to capture the full liquid boundary as obtained by the Mie-scatter results. Funding from NSF REU site Grant EEC 1358991 is greatly appreciated.

  3. 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.

  4. Novel Applications of High Speed Optical-Injection Locked Lasers

    DTIC Science & Technology

    2010-07-31

    frequency response of high speed phototransistors . We have also shown the OIL lasers can significantly extend the reach of optical communications, to I20km...speed InP Heterojunction PhotoTransistors (HPTs). 1 HPT test wafers have been designed and taped out, consisting of single ended HPTs... phototransistors . Light transmitted by the lens fiber and waveguide into the base of the transistor modulates the base current in the device. The

  5. Ultra high speed image processing techniques. [electronic packaging techniques

    NASA Technical Reports Server (NTRS)

    Anthony, T.; Hoeschele, D. F.; Connery, R.; Ehland, J.; Billings, J.

    1981-01-01

    Packaging techniques for ultra high speed image processing were developed. These techniques involve the development of a signal feedthrough technique through LSI/VLSI sapphire substrates. This allows the stacking of LSI/VLSI circuit substrates in a 3 dimensional package with greatly reduced length of interconnecting lines between the LSI/VLSI circuits. The reduced parasitic capacitances results in higher LSI/VLSI computational speeds at significantly reduced power consumption levels.

  6. Quality of service on high-speed data networks

    NASA Astrophysics Data System (ADS)

    Barbero, Ezio; Antonelli, Ferruccio

    1995-02-01

    Since the beginning of this century the issue of `quality' has been gaining increasing importance in a number of fields of human activities. For telecommunication services, too, the quality perceived by customers has been taken into account early on as an issue of strategic importance. Whilst for telephony the Quality of Service (QoS) has been already investigated and identified in terms of parameters and related test methodology, the situation for high speed data services (i.e. CBDS/SMDS, Frame Relay, etc.), provided by means of high speed network based on Asynchronous Transfer Moe (ATM) or Metropolitan Area Network technologies, can still be considered `under study'. There is a death of experience not only in terms of measurement instruments and procedures, but also in terms of knowledge of the relationship between the QoS provided at a network level and the quality perceived by the user on his or her terminal. The complexity of the equipment involved in setting up an end-to-end solution based on high speed data communications makes the problems of knowledge and supply of quality very hard to solve. Starting from the experience gained in carrying out high- speed network field trials based on Metropolitan Area Networks and, more recently, on ATM technology, the paper mainly deals with the problem of defining, measuring and then offering a specific QoS. First, the issue of what the user expects from the `high-speed network' is addressed. This analysis is carried out trying to gather what is peculiar to high-speed data communications from the user standpoint. Next, the focus is on how to cope with the requirements due to users' expectations, while carefully considering the basic principles of quality. Finally, a solution is proposed, starting from the experience gained from high speed networks installed in Italy.

  7. Material requirements for the High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Stephens, Joseph R.; Hecht, Ralph J.; Johnson, Andrew M.

    1993-01-01

    Under NASA-sponsored High Speed Research (HSR) programs, the materials and processing requirements have been identified for overcoming the environmental and economic barriers of the next generation High Speed Civil Transport (HSCT) propulsion system. The long (2 to 5 hours) supersonic cruise portion of the HSCT cycle will place additional durability requirements on all hot section engine components. Low emissions combustor designs will require high temperature ceramic matrix composite liners to meet an emission goal of less than 5g NO(x) per Kg fuel burned. Large axisymmetric and two-dimensional exhaust nozzle designs are now under development to meet or exceed FAR 36 Stage III noise requirements, and will require lightweight, high temperature metallic, intermetallic, and ceramic matrix composites to reduce nozzle weight and meet structural and acoustic component performance goals. This paper describes and discusses the turbomachinery, combustor, and exhaust nozzle requirements of the High Speed Civil Transport propulsion system.

  8. Material requirements for the High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Stephens, Joseph R.; Hecht, Ralph J.; Johnson, Andrew M.

    1993-01-01

    Under NASA-sponsored High Speed Research (HSR) programs, the materials and processing requirements have been identified for overcoming the environmental and economic barriers of the next generation High Speed Civil Transport (HSCT) propulsion system. The long (2 to 5 hours) supersonic cruise portion of the HSCT cycle will place additional durability requirements on all hot section engine components. Low emissions combustor designs will require high temperature ceramic matrix composite liners to meet an emission goal of less than 5g NO(x) per Kg fuel burned. Large axisymmetric and two-dimensional exhaust nozzle designs are now under development to meet or exceed FAR 36 Stage III noise requirements, and will require lightweight, high temperature metallic, intermetallic, and ceramic matrix composites to reduce nozzle weight and meet structural and acoustic component performance goals. This paper describes and discusses the turbomachinery, combustor, and exhaust nozzle requirements of the High Speed Civil Transport propulsion system.

  9. Ultra-high-speed spectropolarimeter based on photoelastic modulator.

    PubMed

    Zhang, Rui; Li, Kewu; Chen, Yuanyuan; Wen, Tingdun; Zhang, Minjuan; Wang, Yaoli; Xue, Peng; Wang, Zhibin

    2016-10-20

    Combined with the advantages of photoelastic modulator (PEM) ultra-high-speed modulation, this paper presents a method of ultra-high-speed spectropolarimeter based on PEM. The method provides the necessary measuring instruments for ultra-high-speed polarization spectroscopy. The main idea of this method is that an intensity modulator consisting of two retarders is placed before the PEM. The incident light under test goes through two retarders to the PEM. The interference signals are obtained by the PEM modulation. The different Stokes element interference signals are modulated by the PEM at different positions of the optical path difference. This method realizes the separation of Stokes element interference signals. The interference signals corresponding to each element are extracted, and the incident light Stokes element spectra can be obtained from the Fourier transforms of the interference signals. The modulation frequency of the PEM is high (tens to hundreds of kilohertz), so this method can realize ultra-high-speed full polarization spectroscopy. A prototype ultra-high-speed spectropolarimeter based on PEM was designed and tested. If the single-sided Fourier transformation is used, the single-sided interferogram scanning time is approximately 5 μs (i.e., the prototype is capable of scanning 20,000 interferograms per second). Polychromatic light polarization spectroscopy is measured by the prototype. The experimental results show that the average error of the prototype is less than 0.03.

  10. Assessment of rural soundscapes with high-speed train noise.

    PubMed

    Lee, Pyoung Jik; Hong, Joo Young; Jeon, Jin Yong

    2014-06-01

    In the present study, rural soundscapes with high-speed train noise were assessed through laboratory experiments. A total of ten sites with varying landscape metrics were chosen for audio-visual recording. The acoustical characteristics of the high-speed train noise were analyzed using various noise level indices. Landscape metrics such as the percentage of natural features (NF) and Shannon's diversity index (SHDI) were adopted to evaluate the landscape features of the ten sites. Laboratory experiments were then performed with 20 well-trained listeners to investigate the perception of high-speed train noise in rural areas. The experiments consisted of three parts: 1) visual-only condition, 2) audio-only condition, and 3) combined audio-visual condition. The results showed that subjects' preference for visual images was significantly related to NF, the number of land types, and the A-weighted equivalent sound pressure level (LAeq). In addition, the visual images significantly influenced the noise annoyance, and LAeq and NF were the dominant factors affecting the annoyance from high-speed train noise in the combined audio-visual condition. In addition, Zwicker's loudness (N) was highly correlated with the annoyance from high-speed train noise in both the audio-only and audio-visual conditions.

  11. HDR {sup 192}Ir source speed measurements using a high speed video camera

    SciTech Connect

    Fonseca, Gabriel P.; Rubo, Rodrigo A.; Sales, Camila P. de; Verhaegen, Frank

    2015-01-15

    Purpose: The dose delivered with a HDR {sup 192}Ir afterloader can be separated into a dwell component, and a transit component resulting from the source movement. The transit component is directly dependent on the source speed profile and it is the goal of this study to measure accurate source speed profiles. Methods: A high speed video camera was used to record the movement of a {sup 192}Ir source (Nucletron, an Elekta company, Stockholm, Sweden) for interdwell distances of 0.25–5 cm with dwell times of 0.1, 1, and 2 s. Transit dose distributions were calculated using a Monte Carlo code simulating the source movement. Results: The source stops at each dwell position oscillating around the desired position for a duration up to (0.026 ± 0.005) s. The source speed profile shows variations between 0 and 81 cm/s with average speed of ∼33 cm/s for most of the interdwell distances. The source stops for up to (0.005 ± 0.001) s at nonprogrammed positions in between two programmed dwell positions. The dwell time correction applied by the manufacturer compensates the transit dose between the dwell positions leading to a maximum overdose of 41 mGy for the considered cases and assuming an air-kerma strength of 48 000 U. The transit dose component is not uniformly distributed leading to over and underdoses, which is within 1.4% for commonly prescribed doses (3–10 Gy). Conclusions: The source maintains its speed even for the short interdwell distances. Dose variations due to the transit dose component are much lower than the prescribed treatment doses for brachytherapy, although transit dose component should be evaluated individually for clinical cases.

  12. High speed commercial transport fuels considerations and research needs

    NASA Technical Reports Server (NTRS)

    Lee, C. M.; Niedzwiecki, R. W.

    1989-01-01

    NASA is currently evaluating the potential of incorporating High Speed Civil Transport (HSCT) aircraft in the commercial fleet in the beginning of the 21st century. NASA sponsored HSCT enabling studies currently underway with airframers and engine manufacturers, are addressing a broad range of technical, environmental, economic, and related issues. Supersonic cruise speeds for these aircraft were originally focused in the Mach 2 to 5 range. At these flight speeds, both jet fuels and liquid methane were considered potential fuel candidates. For the year 2000 to 2010, cruise Mach numbers of 2 to 3+ are projected for aircraft fuel with thermally stable liquid jet fuels. For 2015 and beyond, liquid methane fueled aircraft cruising at Mach numbers of 4+ may be viable candidates. Operation at supersonic speeds will be much more severe than those encountered at subsonic flight. One of the most critical problems is the potential deterioration of the fuel due to the high temperature environment. HSCT fuels will not only be required to provide the energy necessary for flight, but will also be subject to aerodynamic heating and, will be required to serve as the primary heat sink for cooling the engine and airframe. To define fuel problems for high speed flight, a fuels workshop was conducted at NASA Lewis Research Center. The purpose of the workshop was to gather experts on aviation fuels, airframe fuel systems, airport infrastructure, and combustion systems to discuss high speed fuel alternatives, fuel supply scenarios, increased thermal stability approaches and measurements, safety considerations, and to provide directional guidance for future R and D efforts. Subsequent follow-up studies defined airport infrastructure impacts of high speed fuel candidates. The results of these activities are summarized. In addition, an initial case study using modified in-house refinery simulation model Gordian code (1) is briefly discussed. This code can be used to simulate different

  13. The application of high-speed digital image correlation.

    SciTech Connect

    Reu, Phillip L.; Miller, Timothy J.

    2008-02-01

    Digital image correlation (DIC) is a method of using digital images to calculate two-dimensional displacement and deformation or for stereo systems three-dimensional shape, displacement, and deformation. While almost any imaging system can be used with DIC, there are some important challenges when working with the technique in high- and ultra-high-speed applications. This article discusses three of these challenges: camera sensor technology, camera frame rate, and camera motion mitigation. Potential solutions are treated via three demonstration experiments showing the successful application of high-speed DIC for dynamic events. The application and practice of DIC at high speeds, rather than the experimental results themselves, provide the main thrust of the discussion.

  14. Thermal Behavior of High-Speed Helical Gear Trains Investigated

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.

    2003-01-01

    High-speed and heavily loaded gearing are commonplace in the rotorcraft systems employed in helicopter and tiltrotor transmissions. The components are expected to deliver high power from the gas turbine engines to the high-torque, low-speed rotor, reducing the shaft rotational speed in the range of 25:1 to 100:1. These components are designed for high power-to-weight ratios, thus the components are fabricated as light as possible with the best materials and processing to transmit the required torque and carry the resultant loads without compromising the reliability of the drive system. This is a difficult task that is meticulously analyzed and thoroughly tested experimentally prior to being applied on a new or redesigned aircraft.

  15. Custom ASIC development for high-speed Viterbi decoding

    NASA Astrophysics Data System (ADS)

    Miller, S. P.; Becker, N.; Johnson, P. N.

    A high-speed, emitter-coupled logic (ECL) gate array which greatly facilitates the implementation of very-high-speed Viterbi algorithm processors has been developed. These high-speed Viterbi decoders were incorporated into two bandwidth-efficient, jointly optimized coded modulation systems with baseband information rates of 140 and 200 Mb/s. The 200-Mb/s system was developed for NASA under the advanced modulation technology development program. The octal phase shift keying (8PSK) modulation technique used in these systems requires symbol rates of 60 and 75 Msymbol/s. The gate array device also has the potential for use in similar systems with symbol rates in excess of 100 Msymbol/s. Some details of the coded modulation systems that require the implementation of high-speed Viterbi processors are provided to demonstrate current practical applications and the need for this processing capability. The specific gate array design is described in conjunction with the performance goals and measured parameters of the completed device. Performance measurements obtained from high-speed coded modulation systems that use the gate array are also presented to show the performance obtained.

  16. High-speed GaInNAs laser diodes

    NASA Astrophysics Data System (ADS)

    Kondow, Masahiko; Nakahara, Kouji; Fujisaki, S.; Tanaka, Shigehisa; Kudo, M.; Taniguchi, Tadashi; Terano, A.; Uchiyama, H.

    2004-05-01

    The explosive growth of Internet/intranet traffic has created a strong demand for cost-effective high-speed light-sources to be used in local access networks and data links. The frequency of relaxation oscillation (fr) is a major factor that restricts the high-speed operation of laser diodes. To achieve a high fr, the material of an active layer should have a large differential gain. By using GaInNAs, very deep quantum wells, especially in the conduction band can be formed. Deep quantum wells bring a large differential gain. In this paper, we show how GaInNAs lasers can be applied in this application

  17. An Improved Discrete-Time Model for Heterogeneous High-Speed Train Traffic Flow

    NASA Astrophysics Data System (ADS)

    Xu, Yan; Jia, Bin; Li, Ming-Hua; Li, Xin-Gang

    2016-03-01

    This paper aims to present a simulation model for heterogeneous high-speed train traffic flow based on an improved discrete-time model (IDTM). In the proposed simulation model, four train control strategies, including departing strategy, traveling strategy, braking strategy, overtaking strategy, are well defined to optimize train movements. Based on the proposed simulation model, some characteristics of train traffic flow are investigated. Numerical results indicate that the departure time intervals, the station dwell time, the section length, and the ratio of fast trains have different influence on traffic capacity and train average velocity. The results can provide some theoretical support for the strategy making of railway departments. Supported by the National Basic Research Program of China under Grant No. 2012CB725400, the National Natural Science Foundation of China under Grant No. 71222101, the Research Foundation of State Key Laboratory of Rail Traffic Control and Safety under Grant No. RCS2014ZT16, and the Fundamental Research Funds for the Central Universities No. 2015YJS088, Beijing Jiaotong University

  18. Unsteady Flow Simulation of High-speed Turbopumps

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin C.; Kwak, dochan; Chan, William; Housman, Jeffrey A.

    2006-01-01

    Computation of high-speed hydrodynamics requires high-fidelity simulation to resolve flow features involving transient flow, cavitation, tip vortex and multiple scales of unsteady fluctuations. One example of this type in aerospace is related to liquid-fueled rocket turbopump. Rocket turbopumps operate under severe conditions at very high rotational speeds typically at thousands of rpm. For example, the Shuttle orbiter low-pressure-fuel-turbopump creates transient flow features associated with reverse flows, tip clearance effects, secondary flows, vortex shedding, junction flows, and cavitation effects. Flow unsteadiness originating from the orbiter Low-Pressure-Fuel-Turbopump (LPFTP) inducer is one of the major contributors to the high frequency cyclic loading that results in high cycle fatigue damage to the flow liners just upstream of the LPFTP. The reverse flow generated at the tip of the inducer blades travels upstream and interacts with the bellows cavity. Simulation procedure for this type high-speed hydrodynamic problems requires a method for quantifying multi-scale and multi-phase flow as well as an efficient high-end computing strategy. The current paper presents a high-fidelity computational procedure for unsteady hydrodynamic problems using a high-speed liquid-fueled rocket turbopump.

  19. Differences in energy expenditure during high-speed versus standard-speed yoga: A randomized sequence crossover trial.

    PubMed

    Potiaumpai, Melanie; Martins, Maria Carolina Massoni; Rodriguez, Roberto; Mooney, Kiersten; Signorile, Joseph F

    2016-12-01

    To compare energy expenditure and volume of oxygen consumption and carbon dioxide production during a high-speed yoga and a standard-speed yoga program. Randomized repeated measures controlled trial. A laboratory of neuromuscular research and active aging. Sun-Salutation B was performed, for eight minutes, at a high speed versus and a standard-speed separately while oxygen consumption was recorded. Caloric expenditure was calculated using volume of oxygen consumption and carbon dioxide production. Difference in energy expenditure (kcal) of HSY and SSY. Significant differences were observed in energy expenditure between yoga speeds with high-speed yoga producing significantly higher energy expenditure than standard-speed yoga (MD=18.55, SE=1.86, p<0.01). Significant differences were also seen between high-speed and standard-speed yoga for volume of oxygen consumed and carbon dioxide produced. High-speed yoga results in a significantly greater caloric expenditure than standard-speed yoga. High-speed yoga may be an effective alternative program for those targeting cardiometabolic markers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. High-speed cylindrical collapse of two perfect fluids

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Ahmad, Zahid

    2007-09-01

    In this paper, the study of the gravitational collapse of cylindrically distributed two perfect fluid system has been carried out. It is assumed that the collapsing speeds of the two fluids are very large. We explore this condition by using the high-speed approximation scheme. There arise two cases, i.e., bounded and vanishing of the ratios of the pressures with densities of two fluids given by c s , d s . It is shown that the high-speed approximation scheme breaks down by non-zero pressures p 1, p 2 when c s , d s are bounded below by some positive constants. The failure of the high-speed approximation scheme at some particular time of the gravitational collapse suggests the uncertainty on the evolution at and after this time. In the bounded case, the naked singularity formation seems to be impossible for the cylindrical two perfect fluids. For the vanishing case, if a linear equation of state is used, the high-speed collapse does not break down by the effects of the pressures and consequently a naked singularity forms. This work provides the generalisation of the results already given by Nakao and Morisawa (Prog Theor Phys 113:73, 2005) for the perfect fluid.