Impact of high speed civil transports on stratospheric ozone. A 2-D model investigation

Energy Technology Data Exchange (ETDEWEB)

Kinnison, D E; Connell, P S [Lawrence Livermore National Lab., CA (United States)

1998-12-31

This study investigates the effect on stratospheric ozone from a fleet of proposed High Speed Civil Transports (HSCTs). The new LLNL 2-D operator-split chemical-radiative-transport model of the troposphere and stratosphere is used for this HSCT investigation. This model is integrated in a diurnal manner, using an implicit numerical solver. Therefore, rate coefficients are not modified by any sort of diurnal average factor. This model also does not make any assumptions on lumping of chemical species into families. Comparisons to previous model-derived HSCT assessment of ozone change are made, both to the previous LLNL 2-D model and to other models from the international assessment modeling community. The sensitivity to the NO{sub x} emission index and sulfate surface area density is also explored. (author) 7 refs.

Impact of high speed civil transports on stratospheric ozone. A 2-D model investigation

Energy Technology Data Exchange (ETDEWEB)

Kinnison, D.E.; Connell, P.S. [Lawrence Livermore National Lab., CA (United States)

1997-12-31

This study investigates the effect on stratospheric ozone from a fleet of proposed High Speed Civil Transports (HSCTs). The new LLNL 2-D operator-split chemical-radiative-transport model of the troposphere and stratosphere is used for this HSCT investigation. This model is integrated in a diurnal manner, using an implicit numerical solver. Therefore, rate coefficients are not modified by any sort of diurnal average factor. This model also does not make any assumptions on lumping of chemical species into families. Comparisons to previous model-derived HSCT assessment of ozone change are made, both to the previous LLNL 2-D model and to other models from the international assessment modeling community. The sensitivity to the NO{sub x} emission index and sulfate surface area density is also explored. (author) 7 refs.

Smart Sensor Based Obstacle Detection for High-Speed Unmanned Surface Vehicle

DEFF Research Database (Denmark)

Hermann, Dan; Galeazzi, Roberto; Andersen, Jens Christian

2015-01-01

This paper describes an obstacle detection system for a high-speed and agile unmanned surface vehicle (USV), running at speeds up to 30 m/s. The aim is a real-time and high performance obstacle detection system using both radar and vision technologies to detect obstacles within a range of 175 m. ...... performance using sensor fusion of radar and computer vision....

Surface morphology study in high speed milling of soda lime glass

Science.gov (United States)

Konneh, Mohamed; Bagum, Mst. Nasima; Ali, Mohammad Yeakub; Amin, A. K. M. Nurul

2018-05-01

Soda lime glass has a wide range of applications in optical, bio-medical and semi-conductor industries. It is undeniably a challenging task to produce micro finish surface on an amorphous brittle solid like soda lime glass due to its low fracture toughness. In order to obtain such a finish surface, ductile machining has been exploited, as this usually cause's plastic flow which control crack propagation. At sub-micro scale cutting parameters, researchers achieved nano finish surface in micro milling operation using coated tool. However it is possible to enhance the rate of material removal (RMR) of soda lime glass at flexible cutting condition. High speed cutting at micro meter level, extend of thermal softening might be prominent than the strain gradient strengthening. The purpose of this study was to explore the effects of high cutting speed end milling parameters on the surface texture of soda lime glass using uncoated carbide tool. The spindle speed, depth of cut and feed rate were varied from 20,000 to 40,000 rpm, 10 to 30 mm/min and 30 to 50 µm respectively. Mathematical model of roughness has been developed using Response Surface Methodology (RSM). Experimental verification confirmed that surface roughness (Ra) 0.38 µm is possible to achieve at increased RMR, 4.71 mm3/min.

High-speed civil transport issues and technology program

Science.gov (United States)

Hewett, Marle D.

1992-01-01

A strawman program plan is presented, consisting of technology developments and demonstrations required to support the construction of a high-speed civil transport. The plan includes a compilation of technology issues related to the development of a transport. The issues represent technical areas in which research and development are required to allow airframe manufacturers to pursue an HSCT development. The vast majority of technical issues presented require flight demonstrated and validated solutions before a transport development will be undertaken by the industry. The author believes that NASA is the agency best suited to address flight demonstration issues in a concentrated effort. The new Integrated Test Facility at NASA Dryden Flight Research Facility is considered ideally suited to the task of supporting ground validations of proof-of-concept and prototype system demonstrations before night demonstrations. An elaborate ground hardware-in-the-loop (iron bird) simulation supported in this facility provides a viable alternative to developing an expensive fill-scale prototype transport technology demonstrator. Drygen's SR-71 assets, modified appropriately, are a suitable test-bed for supporting flight demonstrations and validations of certain transport technology solutions. A subscale, manned or unmanned flight demonstrator is suitable for flight validation of transport technology solutions, if appropriate structural similarity relationships can be established. The author contends that developing a full-scale prototype transport technology demonstrator is the best alternative to ensuring that a positive decision to develop a transport is reached by the United States aerospace industry.

Impact of Environmental Issues on the High-Speed Civil Transport

Science.gov (United States)

Whitehead, Allen H., Jr.

1998-01-01

This paper provides an overview of the impact of environmental issues on the design and operation of the proposed High-Speed Civil Transport (HSCT). This proposal for a new generation commercial supersonic transport is being pursued by NASA and its US industry partners in the NASA High-Speed Research (HSR) Program. A second related paper describes the overall HSR Program, including a history of supersonic transport development that led to the present program, and a brief outline of the structure of the two-phase program and its management structure. The specific objectives are to address the four major barrier environmental issues and show their impact on the design of the airplane and potentially, its mode of operation. A brief historical perspective shows how HSR Phase I addressed these environmental topics and, with the successful completion of that program, led to the successful advocacy for the Phase II effort that followed. The Phase II program elements were discussed in the earlier paper and addressed technology programs to enhance the economic viability of the HSCT. Since many of the regulations that may effect the certification and operation of the HSCT are either not in place or well documented, a brief treatise is provided to address the status of the rules and the potential impact on the viability of the HSCT.

Surface topography and roughness of high-speed milled AlMn1Cu

Science.gov (United States)

Wang, Zhenhua; Yuan, Juntang; Yin, Zengbin; Hu, Xiaoqiu

2016-10-01

The aluminum alloy AlMn1Cu has been broadly applied for functional parts production because of its good properties. But few researches about the machining mechanism and the surface roughness were reported. The high-speed milling experiments are carried out in order to improve the machining quality and reveal the machining mechanism. The typical topography features of machined surface are observed by scan electron microscope(SEM). The results show that the milled surface topography is mainly characterized by the plastic shearing deformation surface and material piling zone. The material flows plastically along the end cutting edge of the flat-end milling tool and meanwhile is extruded by the end cutting edge, resulting in that materials partly adhere to the machined surface and form the material piling zone. As the depth of cut and the feed per tooth increase, the plastic flow of materials is strengthened and the machined surface becomes rougher. However, as the cutting speed increases, the plastic flow of materials is weakened and the milled surface becomes smoother. The cutting parameters (e.g. cutting speed, feed per tooth and depth of cut) influencing the surface roughness are analyzed. It can be concluded that the roughness of the machined surface formed by the end cutting edge is less than that by the cylindrical cutting edge when a cylindrical flat-end mill tool is used for milling. The proposed research provides the typical topography features of machined surface of the anti-rust aluminum alloy AlMn1Cu in high speed milling.

Propulsion challenges for a 21st century economically viable, environmentally compatible High-Speed Civil Transport

Science.gov (United States)

Shaw, Robert J.

1991-01-01

Recent NASA funded studies suggest an opportunity exists for a 21st Century High Speed Civil Transport (HSCT) to become part of the international air transportation system. However, before this opportunity for high speed travel can be realized, certain environmental and economic barrier issues must be overcome. These challenges are outlined. Research activities which NASA has planned to address these barrier issues and provide a technology base to allow the U.S. manufacturers to make an informed go/no go decision on developing an HSCT are discussed.

High Friction Surface Treatments, Transportation Research Synthesis

Science.gov (United States)

2018-03-01

MnDOT and local transportation agencies in Minnesota are considering the use of a high friction surface treatment (HFST) as a safety strategy. HFST is used as a spot pavement surfacing treatment in locations with high friction demand (for example, cr...

State control of translational movement in high-speed Maglev transportation systems

Energy Technology Data Exchange (ETDEWEB)

Schnieder, E

1981-01-01

The combination of state control with cascade control satisfies all demands made on train movements in a high-speed Maglev transportation system. The inner control loop compensates nonlinearities and disturbances and limits the acceleration. The dynamics of the control loop are determined by the riding characteristics. The superposed speed state control provides for running without overshoot within permissible limits. In order to reach a target point in the shortest possible time, the control signal for initiating the retardation is issued as late as possible and the speed is output as a function of position. The subsequent structure changeover to a position state control causes the train to come to a smooth halt at its destination in an almost optimal time.

Air Transport versus High-Speed Rail: An Overview and Research Agenda

Directory of Open Access Journals (Sweden)

Xiaoqian Sun

2017-01-01

Full Text Available The development of high-speed rail (HSR services throughout the last decades has gradually blurred the concept of competition and cooperation with air transportation. There is a wide range of studies on this subject, with a particular focus on single lines or smaller regions. This article synthesizes and discusses recently published studies in this area, while aiming to identify commonalities and deviations among different regions throughout the world, covering services from Europe, Asia, and North America. Our meta-analysis reveals that the literature is highly controversial and the results vary substantially from one region to another, and a generalization is difficult, given route-specific characteristics, such as demand distribution, network structure, and evolution of transportation modes. As a major contribution, we propose a list of five challenges as a future research agenda on HSR/air transport competition and cooperation. Among others, we see a need for the construction of an open-source dataset for large-scale multimodal transport systems, the comprehensive assessment of new emerging transport modes, and also taking into account the resilience of multimodal transport systems under disruption.

Neutron transport simulation in high speed moving media using Geant4

Science.gov (United States)

Li, G.; Ciungu, B.; Harrisson, G.; Rogge, R. B.; Tun, Z.; van der Ende, B. M.; Zwiers, I.

2017-12-01

A method using Geant4 to simulate neutron transport in moving media is described. The method is implanted in the source code of the software since Geant4 does not intrinsically support a moving object. The simulation utilizes the existing physical model and data library in Geant4, combined with frame transformations to account for the effect of relative velocity between neutrons and the moving media. An example is presented involving a high speed rotating cylinder to verify this method and show the effect of moving media on neutron transport.

Direct visualization of glutamate transporter elevator mechanism by high-speed AFM.

Science.gov (United States)

Ruan, Yi; Miyagi, Atsushi; Wang, Xiaoyu; Chami, Mohamed; Boudker, Olga; Scheuring, Simon

2017-02-14

Glutamate transporters are essential for recovery of the neurotransmitter glutamate from the synaptic cleft. Crystal structures in the outward- and inward-facing conformations of a glutamate transporter homolog from archaebacterium Pyrococcus horikoshii , sodium/aspartate symporter Glt Ph , suggested the molecular basis of the transporter cycle. However, dynamic studies of the transport mechanism have been sparse and indirect. Here we present high-speed atomic force microscopy (HS-AFM) observations of membrane-reconstituted Glt Ph at work. HS-AFM movies provide unprecedented real-space and real-time visualization of the transport dynamics. Our results show transport mediated by large amplitude 1.85-nm "elevator" movements of the transport domains consistent with previous crystallographic and spectroscopic studies. Elevator dynamics occur in the absence and presence of sodium ions and aspartate, but stall in sodium alone, providing a direct visualization of the ion and substrate symport mechanism. We show unambiguously that individual protomers within the trimeric transporter function fully independently.

Green maritime transportation: Speed and route optimization

DEFF Research Database (Denmark)

Psaraftis, Harilaos N.; Kontovas, Christos A.

2015-01-01

Among the spectrum of logistics-based measures for green maritime transportation, this chapter focuses on speed optimization. This involves the selection of an appropriate speed by the vessel, so as to optimize a certain objective. As ship speed is not fixed, depressed shipping markets and/or high...

Polymer Surface Textured with Nanowire Bundles to Repel High-Speed Water Drops.

Science.gov (United States)

Li, Y P; Li, X Y; Zhu, X P; Lei, M K; Lakhtakia, A

2018-05-11

Water drops impacting windshields of high-speed trains and aircraft as well as blades in steam turbine power generators obliquely and at high speeds are difficult to repel. Impacting drops penetrate the void regions of nanotextured and microtextured superhydrophobic coatings, with this pinning resulting in the loss of drop mobility. In order to repel high-speed water drops, we nanotextured polymer surfaces with nanowire bundles separated from their neighbors by microscale void regions, with the nanowires in a bundle separated from their neighbors by nanoscale void regions. Water drops with speeds below a critical speed rebound completely. Water drops with speeds exceeding a critical speed rebound partially, but residual droplets that begin to be pinned undergo a spontaneous dewetting process and slide off. The natural oscillations of residual droplets drive this dewetting process in the interbundle void regions, resulting in a transition from the sticky Wenzel state to the slippery Cassie state without external stimuli.

Newtonian liquid jet impaction on a high-speed moving surface

International Nuclear Information System (INIS)

Keshavarz, B.; Green, S.I.; Davy, M.H.; Eadie, D.T.

2011-01-01

Highlights: ► We studied experimentally the interaction of a liquid jet with a moving surface. ► Decreasing the Reynolds number reduced the incidence of splash. ► The Weber number had a much smaller impact on splash than the Reynolds number. ► The jet impingement angle had only a small effect on the splash. ► Increasing the surface roughness substantially decreased the splash threshold. - Abstract: In the railroad industry a friction modifying agent may be applied to the rail or wheel in the form of a liquid jet. In this mode of application the interaction between the high-speed liquid jet and a fast moving surface is important. Seven different Newtonian liquids with widely varying shear viscosities were tested to isolate the effect of viscosity from other fluid properties. Tests were also done on five surfaces of different roughness heights to investigate the effects of surface roughness. High-speed video imaging was employed to scrutinize the interaction between the impacting jet and the moving surface. For all surfaces, decreasing the Reynolds number reduced the incidence of splash and consequently enhanced the transfer efficiency. At the elevated Weber numbers of the testing, the Weber number had a much smaller impact on splash than the Reynolds number. The ratio of the surface velocity to the jet velocity has only a small effect on the splash, whereas increasing the roughness-height-to-jet-diameter ratio substantially decreased the splash threshold.

Inventory-transportation integrated optimization for maintenance spare parts of high-speed trains

Science.gov (United States)

Wang, Jiaxi; Wang, Huasheng; Wang, Zhongkai; Li, Jian; Lin, Ruixi; Xiao, Jie; Wu, Jianping

2017-01-01

This paper presents a 0–1 programming model aimed at obtaining the optimal inventory policy and transportation mode for maintenance spare parts of high-speed trains. To obtain the model parameters for occasionally-replaced spare parts, a demand estimation method based on the maintenance strategies of China’s high-speed railway system is proposed. In addition, we analyse the shortage time using PERT, and then calculate the unit time shortage cost from the viewpoint of train operation revenue. Finally, a real-world case study from Shanghai Depot is conducted to demonstrate our method. Computational results offer an effective and efficient decision support for inventory managers. PMID:28472097

Fast and accurate: high-speed metrological large-range AFM for surface and nanometrology

Science.gov (United States)

Dai, Gaoliang; Koenders, Ludger; Fluegge, Jens; Hemmleb, Matthias

2018-05-01

Low measurement speed remains a major shortcoming of the scanning probe microscopic technique. It not only leads to a low measurement throughput, but a significant measurement drift over the long measurement time needed (up to hours or even days). To overcome this challenge, PTB, the national metrology institute of Germany, has developed a high-speed metrological large-range atomic force microscope (HS Met. LR-AFM) capable of measuring speeds up to 1 mm s‑1. This paper has introduced the design concept in detail. After modelling scanning probe microscopic measurements, our results suggest that the signal spectrum of the surface to be measured is the spatial spectrum of the surface scaled by the scanning speed. The higher the scanning speed , the broader the spectrum to be measured. To realise an accurate HS Met. LR-AFM, our solution is to combine different stages/sensors synchronously in measurements, which provide a much larger spectrum area for high-speed measurement capability. Two application examples have been demonstrated. The first is a new concept called reference areal surface metrology. Using the developed HS Met. LR-AFM, surfaces are measured accurately and traceably at a speed of 500 µm s‑1 and the results are applied as a reference 3D data map of the surfaces. By correlating the reference 3D data sets and 3D data sets of tools under calibration, which are measured at the same surface, it has the potential to comprehensively characterise the tools, for instance, the spectrum properties of the tools. The investigation results of two commercial confocal microscopes are demonstrated, indicating very promising results. The second example is the calibration of a kind of 3D nano standard, which has spatially distributed landmarks, i.e. special unique features defined by 3D-coordinates. Experimental investigations confirmed that the calibration accuracy is maintained at a measurement speed of 100 µm s‑1, which improves the calibration efficiency by a

Maglev vehicles and superconductor technology: Integration of high-speed ground transportation into the air travel system

Energy Technology Data Exchange (ETDEWEB)

Johnson, L.R.; Rote, D.M.; Hull, J.R.; Coffey, H.T.; Daley, J.G.; Giese, R.F.

1989-04-01

This study was undertaken to (1) evaluate the potential contribution of high-temperature superconductors (HTSCs) to the technical and economic feasibility of magnetically levitated (maglev) vehicles, (2) determine the status of maglev transportation research in the United States and abroad, (3) identify the likelihood of a significant transportation market for high-speed maglev vehicles, and (4) provide a preliminary assessment of the potential energy and economic benefits of maglev systems. HTSCs should be considered as an enhancing, rather than an enabling, development for maglev transportation because they should improve reliability and reduce energy and maintenance costs. Superconducting maglev transportation technologies were developed in the United States in the late 1960s and early 1970s. Federal support was withdrawn in 1975, but major maglev transportation programs were continued in Japan and West Germany, where full-scale prototypes now carry passengers at speeds of 250 mi/h in demonstration runs. Maglev systems are generally viewed as very-high-speed train systems, but this study shows that the potential market for maglev technology as a train system, e.g., from one downtown to another, is limited. Rather, aircraft and maglev vehicles should be seen as complementing rather than competing transportation systems. If maglev systems were integrated into major hub airport operations, they could become economical in many relatively high-density US corridors. Air traffic congestion and associated noise and pollutant emissions around airports would also be reduced. 68 refs., 26 figs., 16 tabs.

High speed surface cleaning by a high repetition rated TEA-CO2 laser

International Nuclear Information System (INIS)

Tsunemi, Akira; Hirai, Ryo; Hagiwara, Kouji; Nagasaka, Keigo; Tashiro, Hideo

1994-01-01

We demonstrated the feasibility of high speed cleaning of solid surfaces by the laser ablation technique using a TEA-CO 2 laser. The laser pulses with the repetition rate of 1 kHz were applied to paint, rust, moss and dirt attached on the surfaces. The attachments were effectively removed without the damage of bulk surfaces by the irradiation of line-focused sequential pulses with an energy of 300 mJ/pulse. A cleaning rate reached to 17 m 2 /hour for the case of paint removal from iron surfaces. (author)

Modern trends in designing high-speed trains

Directory of Open Access Journals (Sweden)

Golubović Snežana D.

2015-01-01

Full Text Available Increased advantages of railway transportation systems over other types of transportation systems in the past sixty years have been a result of an intensive development of the new generations of high-speed trains. Not only do these types of trains comply with the need for increased speed of transportation and make the duration of the journey shorter, but they also meet the demands for increased reliability, safety and direct application of energy efficiency to the transportation system itself. Along with increased train speed, the motion resistance is increased as well, whereby at speeds over 200 km/h the proportion of air resistance becomes the most dominant member. One of the most efficient measures for reducing air resistance, as well as other negative consequences of high-speed motion, is the development of the aerodynamic shape of the train. This paper presents some construction solutions that affect the aerodynamic properties of high-speed trains, first and foremost, the nose shape, as well as the similarities and differences of individual subsystems necessary for the functioning of modern high-speed rail systems. We analysed two approaches to solving the problem of the aerodynamic shape of the train and the appropriate infrastructure using the examples of Japan and France. Two models of high-speed trains, Shinkansen (Japan and TGV, i.e. AGV (France, have been discussed.

The influence of drawing speed on surface topography of high carbon steel wires

Directory of Open Access Journals (Sweden)

M. Suliga

2017-01-01

Full Text Available In this work the influence of the drawing speed on surface topography of high carbon steel wires has been assessed. The drawing process of f 5,5 mm wire rod to the final wire of f 1,7 mm was conducted in 12 passes by means of a modern Koch multi-die drawing machine. The drawing speeds in the last passes were: 5, 10, 15, 20 and 25 m/s. For final wires f 1,7 mm the three-dimensional analysis of the wire surface topography investigation was determined. It has been proved that the wire topography in the drawing process is characterized by a random anisotropy and the amount of directing the geometrical structure of the surface depends on the drawing speed.

Numerical analysis of high-speed liquid lithium free-surface flow

International Nuclear Information System (INIS)

Gordeev, Sergej; Heinzel, Volker; Stieglitz, Robert

2012-01-01

Highlights: ► The free surface behavior of a high speed lithium jet is investigated by means of a CFD LES analysis. ► The study is aiming to validate adequate LES technique. ► The Osaka University experiments with liquid lithium jet have been simulated. ► Four cases with jet flow velocities of 4, 9, 13 and 15 m/s are analyzed. ► Calculation results show a good qualitative and a quantitative agreement with the experimental data. - Abstract: The free-surface stability of the target of the International Fusion Material Irradiation Facility (IFMIF) is one of the crucial issues, since the spatio-temporal behavior of the free-surface determines the neutron flux to be generated. This article investigates the relation between the evolution of a wall boundary layer in a convergent nozzle and the free surface shape of a high speed lithium jet by means of a CFD LES analysis using the Osaka University experiments. The study is aiming to validate adequate LES technique to analyze the individual flow phenomena observed. Four cases with jet flow velocities of 4, 9, 13 and 15 m/s are analyzed. First analyses of calculation results show that the simulation exhibits a good qualitative and a quantitative agreement with the experimental data, which allows in the future a more realistic prediction of the IFMIF target behavior.

An Experiment Study on Surface Roughness in High Speed Milling NAK80 Die Steel

Directory of Open Access Journals (Sweden)

Su Fa

2016-01-01

Full Text Available The paper introduces that the high speed milling experiments on NAK80 die steel was carried out on the DMU 60 mono BLOCK five axis linkage high speed CNC machining center tool by the TiAlN coated tools, in order to research the effect of milling parameters on surface roughness Ra. The results showed that the Ra value increased with the decrease of milling speed vc, increased with the axial depth of milling ap, and feed per tooth fz and radial depth of milling ae. On the basis of the single factor experiment results, the mathematics model for between surface roughness and milling parameters were established by linear regression analysis.

High-speed Imaging of Global Surface Temperature Distributions on Hypersonic Ballistic-Range Projectiles

Science.gov (United States)

Wilder, Michael C.; Reda, Daniel C.

2004-01-01

The NASA-Ames ballistic range provides a unique capability for aerothermodynamic testing of configurations in hypersonic, real-gas, free-flight environments. The facility can closely simulate conditions at any point along practically any trajectory of interest experienced by a spacecraft entering an atmosphere. Sub-scale models of blunt atmospheric entry vehicles are accelerated by a two-stage light-gas gun to speeds as high as 20 times the speed of sound to fly ballistic trajectories through an 24 m long vacuum-rated test section. The test-section pressure (effective altitude), the launch velocity of the model (flight Mach number), and the test-section working gas (planetary atmosphere) are independently variable. The model travels at hypersonic speeds through a quiescent test gas, creating a strong bow-shock wave and real-gas effects that closely match conditions achieved during actual atmospheric entry. The challenge with ballistic range experiments is to obtain quantitative surface measurements from a model traveling at hypersonic speeds. The models are relatively small (less than 3.8 cm in diameter), which limits the spatial resolution possible with surface mounted sensors. Furthermore, since the model is in flight, surface-mounted sensors require some form of on-board telemetry, which must survive the massive acceleration loads experienced during launch (up to 500,000 gravities). Finally, the model and any on-board instrumentation will be destroyed at the terminal wall of the range. For these reasons, optical measurement techniques are the most practical means of acquiring data. High-speed thermal imaging has been employed in the Ames ballistic range to measure global surface temperature distributions and to visualize the onset of transition to turbulent-flow on the forward regions of hypersonic blunt bodies. Both visible wavelength and infrared high-speed cameras are in use. The visible wavelength cameras are intensified CCD imagers capable of integration

Cavitation induced by high speed impact of a solid surface on a liquid jet

Science.gov (United States)

Farhat, Mohamed; Tinguely, Marc; Rouvinez, Mathieu

2009-11-01

A solid surface may suffer from severe erosion if it impacts a liquid jet at high speed. The physics behind the erosion process remains unclear. In the present study, we have investigated the impact of a gun bullet on a laminar water jet with the help of a high speed camera. The bullet has a flat front and 11 mm diameter, which is half of jet diameter. The impact speed was varied between 200 and 500 ms-1. Immediately after the impact, a systematic shock wave and high speed jetting were observed. As the compression waves reflect on the jet boundary, a spectacular number of vapour cavities are generated within the jet. Depending on the bullet velocity, these cavities may grow and collapse violently on the bullet surface with a risk of cavitation erosion. We strongly believe that this transient cavitation is the main cause of erosion observed in many industrial applications such as Pelton turbines.

Investigation of multi-scale flash-weakening of rock surfaces during high speed slip

Science.gov (United States)

Barbery, M. R.; Saber, O.; Chester, F. M.; Chester, J. S.

2017-12-01

A significant reduction in the coefficient of friction of rock can occur if sliding velocity approaches seismic rates as a consequence of weakening of microscopic sliding contacts by flash heating. Using a high-acceleration and -speed biaxial apparatus equipped with a high-speed Infra-Red (IR) camera to capture thermographs of the sliding surface, we have documented the heterogeneous distribution of temperature on flash-heated decimetric surfaces characterized by linear arrays of high-temperature, mm-size spots, and streaks. Numerical models that are informed by the character of flash heated surfaces and that consider the coupling of changes in temperature and changes in the friction of contacts, supports the hypothesis that independent mechanisms of flash weakening operate at different contact scales. Here, we report on new experiments that provide additional constraints on the life-times and rest-times of populations of millimeter-scale contacts. Rock friction experiments conducted on Westerly granite samples in a double-direct shear configuration achieve velocity steps from 1 mm/s to 900 mm/s at 100g accelerations over 2 mm of displacement with normal stresses of 22-36 MPa and 30 mm of displacement during sustained high-speed sliding. Sliding surfaces are machined to roughness similar to natural fault surfaces and that allow us to control the characteristics of millimeter-scale contact populations. Thermographs of the sliding surface show temperatures up to 200 C on millimeter-scale contacts, in agreement with 1-D heat conduction model estimates of 180 C. Preliminary comparison of thermal modeling results and experiment observations demonstrate that we can distinguish the different life-times and rest-times of contacts in thermographs and the corresponding frictional weakening behaviors. Continued work on machined surfaces that lead to different contact population characteristics will be used to test the multi-scale and multi-mechanism hypothesis for flash

Human engineering analysis for the high speed civil transport flight deck

Science.gov (United States)

Regal, David M.; Alter, Keith W.

1993-01-01

The Boeing Company is investigating the feasibility of building a second generation supersonic transport. If current studies support its viability, this airplane, known as the High Speed Civil Transport (HSCT), could be launched early in the next century. The HSCT will cruise at Mach 2.4, be over 300 feet long, have an initial range of between 5000 and 6000 NM, and carry approximately 300 passengers. We are presently involved in developing an advanced flight deck for the HSCT. As part of this effort we are undertaking a human engineering analysis that involves a top-down, mission driven approach that will allow a systematic determination of flight deck functional and information requirements. The present paper describes this work.

Hull Surface Information Retrieval and Optimization of High Speed Planing Craft

International Nuclear Information System (INIS)

Ayob, A F; Wan Nik, W B; Ray, T; Smith, W F

2012-01-01

Traditional approach on ship design involve the use of a method which takes a form that was earlier called the 'general design diagram' and is now known as the 'design spiral' – an iterative ship design process that allows for an increase in complexity and precision across the design cycle. Several advancements have been made towards the design spiral, however inefficient for handling complex simultaneous design changes, especially when later variable changes affect the ship's performance characteristics evaluated in earlier stages. Reviewed in this paper are several advancements in high speed planing craft design in preliminary design stage. An optimization framework for high speed planing craft is discussed which consist of surface information retrieval module, a suite of state-of-the-art optimization algorithms and standard naval architectural performance estimation tools. A summary of the implementation of the proposed hull surface information retrieval and several case studies are presented to demonstrate the capabilities of the framework.

Applications of endothermic research technology to the high speed civil transport

Science.gov (United States)

Glickstein, M. R.; Spadaccini, L. J.

1997-01-01

The success of strategies for controlling emissions and enhancing performance in High Speed Research applications may be increased by more effective utilization of the heat sink afforded by the fuel in the vehicle thermal management system. This study quantifies the potential benefits associated with the use of supercritical preheating and endothermic cracking of jet fuel prior to combustion to enhance the thermal management capabilities of the propulsion systems in the High Speed Civil Transport (HSCT). A fuel-cooled thermal management system, consisting of plate-fin heat exchangers and a small auxiliary compressor, is defined for the HSCT, integrated with the engine, and an assessment of the effect on engine performance, weight, and operating cost is performed. The analysis indicates significant savings due a projected improvement in fuel economy, and the potential for additional benefit if the cycle is modified to take full advantage of all the heat sink available in the fuel.

Spatiotemporal Structure of Aeolian Particle Transport on Flat Surface

Science.gov (United States)

Niiya, Hirofumi; Nishimura, Kouichi

2017-05-01

We conduct numerical simulations based on a model of blowing snow to reveal the long-term properties and equilibrium state of aeolian particle transport from 10-5 to 10 m above the flat surface. The numerical results are as follows. (i) Time-series data of particle transport are divided into development, relaxation, and equilibrium phases, which are formed by rapid wind response below 10 cm and gradual wind response above 10 cm. (ii) The particle transport rate at equilibrium is expressed as a power function of friction velocity, and the index of 2.35 implies that most particles are transported by saltation. (iii) The friction velocity below 100 µm remains roughly constant and lower than the fluid threshold at equilibrium. (iv) The mean particle speed above 300 µm is less than the wind speed, whereas that below 300 µm exceeds the wind speed because of descending particles. (v) The particle diameter increases with height in the saltation layer, and the relationship is expressed as a power function. Through comparisons with the previously reported random-flight model, we find a crucial problem that empirical splash functions cannot reproduce particle dynamics at a relatively high wind speed.

Prototype high-speed tape target transport for a laser plasma soft-x-ray projection lithography source

International Nuclear Information System (INIS)

Haney, S.J.; Berger, K.W.; Kubiak, G.D.; Rockett, P.D.; Hunter, J.

1993-01-01

A prototype high-speed tape target transport is constructed for use in a high-repetition-rate laser plasma source. To reduce plasma debris, a 1000--5000-A-thick film of target material is supported by thin Mylar tape backing. Tape is transported to the laser focal volume at a maximum velocity of 356 cm/s, a rate sufficient to accommodate laser repetition rates of 1 kHz. The transport is fully vacuum compatible and can be retracted and then isolated from the laser plasma vacuum enclosure during tape reel replacement. The operating characteristics of the transport are described

City transport of the future - the high speed pedestrian conveyor. Part 1: ergonomic considerations of accelerators, decelerators and transfer sections.

Science.gov (United States)

Browning, A C

1974-12-01

In this article, an uncommon form of passenger transport is considered, the moving pavement or pedestrian conveyor running at speeds of up to 16 km/h. There are very little relevant ergonomic data for such devices and some specific laboratory experiments have been carried out using 1000 subjects to represent the general public. It is concluded that whilst high speed pedestrian conveyors are quite feasible, stations along them are likely to be large. The most attractive type is a set of parallel surfaces moving at different speeds and with handholds provided in the form of poles. This type could be extremely convenient for certain locations but will probably have to be restricted in its use to fairly fit adults carrying little luggage, and would find applications in situations where a large number of people need to travel in the same direction. Part 2, Ergonomic considerations of complete conveyor systems, will follow.

General factors that affects the increase of population mobility and principles of optimization of high-speed passenger transportations

OpenAIRE

Momot, A.

2014-01-01

Purpose. Analyze the main factors that influence the increased mobility of the population in the transport market of Ukraine. Methods. The article uses an improved method of determining the optimal areas of high-speed passenger trains and determines the value of rational transportation of passengers in different directions of speed traffic, as well as the method of marginal income. Results. In this article we analyzed seven major factors that influence the increased mobility of the population...

California statewide model for high-speed rail

OpenAIRE

Outwater, Maren; Tierney, Kevin; Bradley, Mark; Sall, Elizabeth; Kuppam, Arun; Modugala, Vamsee

2010-01-01

The California High Speed Rail Authority (CHSRA) and the Metropolitan Transportation Commission (MTC) have developed a new statewide model to support evaluation of high-speed rail alternatives in the State of California. This statewide model will also support future planning activities of the California Department of Transportation (Caltrans). The approach to this statewide model explicitly recognizes the unique characteristics of intraregional travel demand and interregional travel demand. A...

Transport properties of high-temperature superconductors: Surface vs bulk effect

International Nuclear Information System (INIS)

Burlachkov, L.; Koshelev, A.E.; Vinokur, V.M.

1996-01-01

We investigate surface-related transport properties of high-temperature superconductors. We find the mean vortex velocity under applied transport current determined by the activation energies for vortex penetration and exit through the Bean-Livingston barrier. We determine the current distribution between the surfaces of superconductor and the field and current dependencies of the transport activation energies. For a three-dimensional superconductor the transport activation energy, U s 3D , is found to decrease with the external field, H, and transport current, J, as U s 3D ∝H -1/2 and U s 3D ∝J -1/2 , respectively. In the quasi-two-dimensional compounds, U s 2D decays logarithmically with field and current. The interplay between the surface and the bulk contributions to the transport properties, such as current-voltage characteristics, is discussed. copyright 1996 The American Physical Society

Molecular dynamic simulations of the high-speed copper nanoparticles collision with the aluminum surface

Science.gov (United States)

Pogorelko, V. V.; Mayer, A. E.

2016-11-01

With the use of the molecular dynamic simulations, we investigated the effect of the high-speed (500 m/s, 1000 m/s) copper nanoparticle impact on the mechanical properties of an aluminum surface. Dislocation analysis shows that a large number of dislocations are formed in the impact area; the total length of dislocations is determined not only by the speed and size of the incoming copper nanoparticle (kinetic energy of the nanoparticle), but by a temperature of the system as well. The dislocations occupy the whole area of the aluminum single crystal at high kinetic energy of the nanoparticle. With the decrease of the nanoparticle kinetic energy, the dislocation structures are formed in the near-surface layer; formation of the dislocation loops takes place. Temperature rise of the system (aluminum substrate + nanoparticle) reduces the total dislocation length in the single crystal of aluminum; there is deeper penetration of the copper atoms in the aluminum at high temperatures. Average energy of the nanoparticles and room temperature of the system are optimal for production of high-quality layers of copper on the aluminum surface.

CHEETAH: circuit-switched high-speed end-to-end transport architecture

Science.gov (United States)

Veeraraghavan, Malathi; Zheng, Xuan; Lee, Hyuk; Gardner, M.; Feng, Wuchun

2003-10-01

Leveraging the dominance of Ethernet in LANs and SONET/SDH in MANs and WANs, we propose a service called CHEETAH (Circuit-switched High-speed End-to-End Transport ArcHitecture). The service concept is to provide end hosts with high-speed, end-to-end circuit connectivity on a call-by-call shared basis, where a "circuit" consists of Ethernet segments at the ends that are mapped into Ethernet-over-SONET long-distance circuits. This paper focuses on the file-transfer application for such circuits. For this application, the CHEETAH service is proposed as an add-on to the primary Internet access service already in place for enterprise hosts. This allows an end host that is sending a file to first attempt setting up an end-to-end Ethernet/EoS circuit, and if rejected, fall back to the TCP/IP path. If the circuit setup is successful, the end host will enjoy a much shorter file-transfer delay than on the TCP/IP path. To determine the conditions under which an end host with access to the CHEETAH service should attempt circuit setup, we analyze mean file-transfer delays as a function of call blocking probability in the circuit-switched network, probability of packet loss in the IP network, round-trip times, link rates, and so on.

Latest Progress in Research on the SpaceLiner High-Speed Passenger Transportation Concept

OpenAIRE

Sippel, Martin; van Foreest, Arnold

2007-01-01

A vision aimed at revolutionizing ultra-long distance travel between different points on earth could be realized by a high-speed intercontinental passenger transport using rocket based, suborbital launchers. The paper gives an overview on the latest progress in conceptual design of the DLR SpaceLiner presenting geometrical size and mass data and describing results of trajectory simulations. The rockets are based on an advanced but technically conservative approach not relying on e...

Chicago-St. Louis high speed rail plan

International Nuclear Information System (INIS)

Stead, M.E.

1994-01-01

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

Chicago-St. Louis high speed rail plan

Energy Technology Data Exchange (ETDEWEB)

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.

High-speed Fourier transform profilometry for reconstructing objects having arbitrary surface colours

International Nuclear Information System (INIS)

Chen, Liang-Chia; Nguyen, Xuan Loc; Zhang, Fu-Hao; Lin, Tzeng-Yow

2010-01-01

In this paper, Fourier transform profilometry (FTP) using a colour fringe selection technique for accurate phase map reconstruction is newly proposed to overcome the limitation of FTP in measuring objects having arbitrary surface colours. The sinusoidal colour fringe pattern is encoded to form a unique colour pattern for projecting onto the object's surface, and its reflected deformed fringe image is taken using a triple-colour CCD camera and rapidly processed by the developed FTP method employing a novel band-pass filter. A new 3D vision system is capable of measuring objects with a high speed of up to 60 frames s −1 . To reconstruct the 3D profile of an object having arbitrary surface colours, an innovative strategy is developed to identify the colour channel of the detected fringe pattern with the best modulation transfer function (MTF) for retrieving accurate phase maps. The experimental results demonstrate that the system has the capability to acquire 3D maps at a high speed while the measurement accuracy of the developed method is substantially better than that of the traditional FTP method. By measuring the standard step heights in a repeatability test, it is confirmed that a maximum measured error can be controlled to less than 2.8% of the overall measuring depth range

Supercavitating flow around high-speed underwater projectile near free surface induced by air entrainment

Directory of Open Access Journals (Sweden)

Chang Xu

2018-03-01

Full Text Available Cavitating flow near free surface is a complicated issue and may provide new inspiration on high-speed surface cruising. This study observes stable supercavitating flow as a new phenomenon in a launch experiment of axisymmetric projectile when the upper side of the projectile coincides with the free surface. A numerical approach is established using large eddy-simulation and volume-of-fluid methods, and good agreements are achieved between numerical and experimental results. Supercavity formation mechanism is revealed by analyzing the experiment photographs and the iso-surface of 90% water volume fraction in numerical results. The entrainment of a large amount of air into the cavity can cause the pressure inside the cavity to similarly increase with the pressure outside the cavity, which makes the actual cavitation number close to zero and is similar to supercavitation. Cases with various headforms of the projectile and cavitation numbers on the cavitating flow, as well as the drag reduction effects are further examined. Results indicate that the present strategy near the free surface could possibly be a new effective approach for high-speed cruising after vigorous design optimization in the future.

Submonolayer Quantum Dots for High Speed Surface Emitting Lasers

Directory of Open Access Journals (Sweden)

Zakharov ND

2007-01-01

Full Text Available AbstractWe report on progress in growth and applications of submonolayer (SML quantum dots (QDs in high-speed vertical-cavity surface-emitting lasers (VCSELs. SML deposition enables controlled formation of high density QD arrays with good size and shape uniformity. Further increase in excitonic absorption and gain is possible with vertical stacking of SML QDs using ultrathin spacer layers. Vertically correlated, tilted or anticorrelated arrangements of the SML islands are realized and allow QD strain and wavefunction engineering. Respectively, both TE and TM polarizations of the luminescence can be achieved in the edge-emission using the same constituting materials. SML QDs provide ultrahigh modal gain, reduced temperature depletion and gain saturation effects when used in active media in laser diodes. Temperature robustness up to 100 °C for 0.98 μm range vertical-cavity surface-emitting lasers (VCSELs is realized in the continuous wave regime. An open eye 20 Gb/s operation with bit error rates better than 10−12has been achieved in a temperature range 25–85 °Cwithout current adjustment. Relaxation oscillations up to ∼30 GHz have been realized indicating feasibility of 40 Gb/s signal transmission.

Enhancing the connectivity of high speed rail in the Orlando-Tampa corridor with local public transportation systems : issues and opportunities.

Science.gov (United States)

2011-01-01

High Speed Rail (HSR) will only be truly transformational if it has effective connections with as many other modes of transportation as possible. This project looks at local public transportation systems that have opportunities to connect to HSR stat...

Full-frame, high-speed 3D shape and deformation measurements using stereo-digital image correlation and a single color high-speed camera

Science.gov (United States)

Yu, Liping; Pan, Bing

2017-08-01

Full-frame, high-speed 3D shape and deformation measurement using stereo-digital image correlation (stereo-DIC) technique and a single high-speed color camera is proposed. With the aid of a skillfully designed pseudo stereo-imaging apparatus, color images of a test object surface, composed of blue and red channel images from two different optical paths, are recorded by a high-speed color CMOS camera. The recorded color images can be separated into red and blue channel sub-images using a simple but effective color crosstalk correction method. These separated blue and red channel sub-images are processed by regular stereo-DIC method to retrieve full-field 3D shape and deformation on the test object surface. Compared with existing two-camera high-speed stereo-DIC or four-mirror-adapter-assisted singe-camera high-speed stereo-DIC, the proposed single-camera high-speed stereo-DIC technique offers prominent advantages of full-frame measurements using a single high-speed camera but without sacrificing its spatial resolution. Two real experiments, including shape measurement of a curved surface and vibration measurement of a Chinese double-side drum, demonstrated the effectiveness and accuracy of the proposed technique.

Evaluation of cutting force and surface roughness in high-speed milling of compacted graphite iron

Directory of Open Access Journals (Sweden)

Azlan Suhaimi Mohd

2017-01-01

Full Text Available Compacted Graphite Iron, (CGI is known to have outstanding mechanical strength and weight-to-strength ratio as compared to conventional grey cast iron, (CI. The outstanding characteristics of CGI is due to its graphite particle shape, which is presented as compacted vermicular particle. The graphite is interconnected with random orientation and round edges, which results in higher mechanical strength. Whereas, graphite in the CI consists of a smooth-surfaced flakes that easily propagates cracks which results in weaker and brittle properties as compared to CGI. Owing to its improved properties, CGI is considered as the best candidate material in substituting grey cast iron that has been used in engine block applications for years. However, the smooth implementation of replacing CI with CGI has been hindered due to the poor machinability of CGI especially at high cutting speed. The tool life is decreased by 20 times when comparing CGI with CI under the same cutting condition. This study investigates the effect of using cryogenic cooling and minimum quantity lubrication (MQL during high-speed milling of CGI (grade 450. Results showed that, the combination of internal cryogenic cooling and enhanced MQL improved the tool life, cutting force and surface quality as compared to the conventional flood coolant strategy during high-speed milling of CGI.

High-Speed RaPToRS

Science.gov (United States)

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.

High speed magnetically levitated transport systems: Technical and economic aspects. Sistemi di trasporto ad alta velocita' a levitazione magnetica: Considerazioni tecniche ed economiche

Energy Technology Data Exchange (ETDEWEB)

Martinelli, G; Morini, A [Padua Univ. (Italy)

1992-11-01

In assessing the current state of technology relative to high speed (400 to 500 km/h) magnetically levitated (MAGLEV) transportation systems, this paper compares the technical aspects of the two main types of suspension systems now being developed specifically for these transportation systems, i.e., attractive electromagnetic using conventional magnets, and repulsive electrodynamic using superconducting magnets. Commercialization prospects for these systems are reviewed by analyzing areas where high speed levitated trains could compete against conventional rail and air transportation systems. The technology review includes progress reports on research and developments activities taking place in Germany and Japan, as well as, descriptions of some recent applications of this technology.

SEAL FOR HIGH SPEED CENTRIFUGE

Science.gov (United States)

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.

Superconducting solenoids for suspension of high-speed overhead transportation facilities

Energy Technology Data Exchange (ETDEWEB)

Omel' yanenko, V I [Kharkov Polytechnical Inst., USSR; Bocharov, V I; Dolgosheev, E A; Usichenko, Y G

1977-08-01

A superconducting solenoid is the most important component of a suspension for overhead transportation facilities operating on the repulsion principle. Its design is aimed at producing an adequate magnetic field within the active zone, to ensure a high ratio of lifting force to braking force, the necessary speed dependence of both forces, and a high ratio of lifting force to solenoid mass. The design must also be both technologically and economically feasible. For safety considerations, the magnetic field intensity inside the passenger compartment must be minimum. A survey of existing designs indicates a preference for race track solenoids of quasi-rectangular shape. While all designers already agree on a coil width within 0.25 to 0.6 m, the optimum coil length has not yet been established. Intrinsic stabilization of superconductors by stranding and twisting has pushed the maximum allowable current density to 200 A/mm/sup 2/ and the energy storing capacity of magnets to 100 kJ, a capacity of 1 MJ being within reach. The recommended coil dimensions for laboratory models are 1 m length and 0.3 m width, to carry magnetizing currents up to 0.3 MA.

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

Science.gov (United States)

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

2018-06-01

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

Integrated design and manufacturing for the high speed civil transport

Science.gov (United States)

1993-01-01

In June 1992, Georgia Tech's School of Aerospace Engineering was awarded a NASA University Space Research Association (USRA) Advanced Design Program (ADP) to address 'Integrated Design and Manufacturing for the High Speed Civil Transport (HSCT)' in its graduate aerospace systems design courses. This report summarizes the results of the five courses incorporated into the Georgia Tech's USRA ADP program. It covers AE8113: Introduction to Concurrent Engineering, AE4360: Introduction to CAE/CAD, AE4353: Design for Life Cycle Cost, AE6351: Aerospace Systems Design One, and AE6352: Aerospace Systems Design Two. AE8113: Introduction to Concurrent Engineering was an introductory course addressing the basic principles of concurrent engineering (CE) or integrated product development (IPD). The design of a total system was not the objective of this course. The goal was to understand and define the 'up-front' customer requirements, their decomposition, and determine the value objectives for a complex product, such as the high speed civil transport (HSCT). A generic CE methodology developed at Georgia Tech was used for this purpose. AE4353: Design for Life Cycle Cost addressed the basic economic issues for an HSCT using a robust design technique, Taguchi's parameter design optimization method (PDOM). An HSCT economic sensitivity assessment was conducted using a Taguchi PDOM approach to address the robustness of the basic HSCT design. AE4360: Introduction to CAE/CAD permitted students to develop and utilize CAE/CAD/CAM knowledge and skills using CATIA and CADAM as the basic geometric tools. AE6351: Aerospace Systems Design One focused on the conceptual design refinement of a baseline HSCT configuration as defined by Boeing, Douglas, and NASA in their system studies. It required the use of NASA's synthesis codes FLOPS and ACSYNT. A criterion called the productivity index (P.I.) was used to evaluate disciplinary sensitivities and provide refinements of the baseline HSCT

Analysis of a high speed train impact on a fuel transport flask

International Nuclear Information System (INIS)

Dowler, H.J.

1983-05-01

Current requirements for flask testing involve the recommended IAEA 9m drop test onto a flat unyielding surface. However, in practice impacts may occur at speeds far greater than the 30 mph equivalent of a 9m drop but into a yielding target. Additionally, the flask itself may be the target. This report investigates the postulated accident of a high speed train travelling at 125 mph impacting a stationary flask. The objectives of this report are to establish the forces that are involved and to put them into the context of the regulation drop tests, to investigate what effects the train as a whole has on the impact and to identify the significant parameters that determine the force level. A one dimensional model of the train is used to obtain the flask loading when the flask is both fixed and free, these giving the upper and lower bounds for all possible flask constraints. (author)

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

Science.gov (United States)

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... monorail systems operating primarily on dedicated rail (i.e., not used by freight trains) or guideway, in...

A transport layer protocol for the future high speed grid computing: SCTP versus fast tcp multihoming

International Nuclear Information System (INIS)

Arshad, M.J.; Mian, M.S.

2010-01-01

TCP (Transmission Control Protocol) is designed for reliable data transfer on the global Internet today. One of its strong points is its use of flow control algorithm that allows TCP to adjust its congestion window if network congestion is occurred. A number of studies and investigations have confirmed that traditional TCP is not suitable for each and every type of application, for example, bulk data transfer over high speed long distance networks. TCP sustained the time of low-capacity and short-delay networks, however, for numerous factors it cannot be capable to efficiently deal with today's growing technologies (such as wide area Grid computing and optical-fiber networks). This research work surveys the congestion control mechanism of transport protocols, and addresses the different issues involved for transferring the huge data over the future high speed Grid computing and optical-fiber networks. This work also presents the simulations to compare the performance of FAST TCP multihoming with SCTP (Stream Control Transmission Protocol) multihoming in high speed networks. These simulation results show that FAST TCP multihoming achieves bandwidth aggregation efficiently and outperforms SCTP multihoming under a similar network conditions. The survey and simulation results presented in this work reveal that multihoming support into FAST TCP does provide a lot of benefits like redundancy, load-sharing and policy-based routing, which largely improves the whole performance of a network and can meet the increasing demand of the future high-speed network infrastructures (such as in Grid computing). (author)

Aerodynamic design on high-speed trains

Science.gov (United States)

Ding, San-San; Li, Qiang; Tian, Ai-Qin; Du, Jian; Liu, Jia-Li

2016-04-01

Compared with the traditional train, the operational speed of the high-speed train has largely improved, and the dynamic environment of the train has changed from one of mechanical domination to one of aerodynamic domination. The aerodynamic problem has become the key technological challenge of high-speed trains and significantly affects the economy, environment, safety, and comfort. In this paper, the relationships among the aerodynamic design principle, aerodynamic performance indexes, and design variables are first studied, and the research methods of train aerodynamics are proposed, including numerical simulation, a reduced-scale test, and a full-scale test. Technological schemes of train aerodynamics involve the optimization design of the streamlined head and the smooth design of the body surface. Optimization design of the streamlined head includes conception design, project design, numerical simulation, and a reduced-scale test. Smooth design of the body surface is mainly used for the key parts, such as electric-current collecting system, wheel truck compartment, and windshield. The aerodynamic design method established in this paper has been successfully applied to various high-speed trains (CRH380A, CRH380AM, CRH6, CRH2G, and the Standard electric multiple unit (EMU)) that have met expected design objectives. The research results can provide an effective guideline for the aerodynamic design of high-speed trains.

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

Science.gov (United States)

2010-04-01

...; Enhancing intercity travel options; Ensuring a state of good repair of key intercity passenger rail assets... DEPARTMENT OF TRANSPORTATION Federal Railroad Administration High-Speed Intercity Passenger Rail... selections for the High-Speed Intercity Passenger Rail (HSIPR) Program. This notice builds on the program...

Single-mode temperature and polarisation-stable high-speed 850nm vertical cavity surface emitting lasers

International Nuclear Information System (INIS)

Nazaruk, D E; Blokhin, S A; Maleev, N A; Bobrov, M A; Pavlov, M M; Kulagina, M M; Vashanova, K A; Zadiranov, Yu M; Ustinov, V M; Kuzmenkov, A G; Vasil'ev, A P; Gladyshev, A G; Blokhin, A A; Salut, 7 Larina Str, N Novgorod, 603950 (Russian Federation))" data-affiliation=" (JSV Salut, 7 Larina Str, N Novgorod, 603950 (Russian Federation))" >Fefelov, A G

2014-01-01

A new intracavity-contacted design to realize temperature and polarization-stable high-speed single-mode 850 nm vertical cavity surface emitting lasers (VCSELs) grown by molecular-beam epitaxy is proposed. Temperature dependences of static and dynamic characteristics of the 4.5 pm oxide aperture InGaAlAs VCSEL were investigated in detail. Due to optimal gain-cavity detuning and enhanced carrier localization in the active region the threshold current remains below 0.75 mA for the temperature range within 20-90°C, while the output power exceeds 1 mW up to 90°C. Single-mode operation with side-mode suppression ratio higher than 30 dB and orthogonal polarization suppression ratio more than 18 dB was obtained in the whole current and temperature operation range. Device demonstrates serial resistance less than 250 Ohm, which is rather low for any type of single-mode short- wavelength VCSELs. VCSEL demonstrates temperature robust high-speed operation with modulation bandwidth higher than 13 GHz in the entire temperature range of 20-90°C. Despite high resonance frequency the high-speed performance of developed VCSELs was limited by the cut-off frequency of the parasitic low pass filter created by device resistances and capacitances. The proposed design is promising for single-mode high-speed VCSEL applications in a wide spectral range

A current review of high speed railways experiences in Asia and Europe

Science.gov (United States)

Purba, Aleksander; Nakamura, Fumihiko; Dwsbu, Chatarina Niken; Jafri, Muhammad; Pratomo, Priyo

2017-11-01

High-Speed Railways (HSR) is currently regarded as one of the most significant technological breakthroughs in passenger transportation developed in the second half of the 20th century. At the beginning of 2008, there were about 10,000 kilometers of new high-speed lines in operation in Asia and Europe regions to provide high-speed services to passengers willing to pay for lower travel time and quality improvement in rail transport. And since 2010, HSR itself has received a great deal of attention in Indonesia. Some transportation analysts contend that Indonesia, particularly Java and Sumatera islands need a high-speed rail network to be economically competitive with countries in Asia and Europe. On April 2016, Indonesia-China consortium Kereta Cepat Indonesia China (KCIC) signed an engineering, procurement, and construction contract to build the HSR with a consortium of seven companies called the High-Speed Railway Contractor Consortium. The HSR is expected to debut by May 2019, offering a 45-minute trip covering a roughly 150 km route. However, building, maintaining and operating HSR line is expensive; it involves a significant amount of sunk costs and may substantially compromise both the transport policy of a country and the development of its transport sector for decades. The main objective of this paper is to discuss some characteristics of the HSR services from an economic viewpoint, while simultaneously developing an empirical framework that should help us to understand, in more detail, the factors determining the success of the HSR as transport alternative based on current experiences of selected Asian and European countries.

High Speed Rail (HSR) in the United States

Science.gov (United States)

2009-12-08

announced that it will expand the capacity on its aging high speed line between Tokyo and Osaka, the most heavily traveled intercity rail segment in the...United States, in most of these countries intercity rail travel (including both conventional and high speed rail) represents less than 10% of all...that is sometimes mentioned by its advocates. Intercity passenger rail transport is relatively safe, at least compared with highway travel . And HSR in

Fabrication of wear-resistant silicon microprobe tips for high-speed surface roughness scanning devices

Science.gov (United States)

Wasisto, Hutomo Suryo; Yu, Feng; Doering, Lutz; Völlmeke, Stefan; Brand, Uwe; Bakin, Andrey; Waag, Andreas; Peiner, Erwin

2015-05-01

Silicon microprobe tips are fabricated and integrated with piezoresistive cantilever sensors for high-speed surface roughness scanning systems. The fabrication steps of the high-aspect-ratio silicon microprobe tips were started with photolithography and wet etching of potassium hydroxide (KOH) resulting in crystal-dependent micropyramids. Subsequently, thin conformal wear-resistant layer coating of aluminum oxide (Al2O3) was demonstrated on the backside of the piezoresistive cantilever free end using atomic layer deposition (ALD) method in a binary reaction sequence with a low thermal process and precursors of trimethyl aluminum and water. The deposited Al2O3 layer had a thickness of 14 nm. The captured atomic force microscopy (AFM) image exhibits a root mean square deviation of 0.65 nm confirming the deposited Al2O3 surface quality. Furthermore, vacuum-evaporated 30-nm/200-nm-thick Au/Cr layers were patterned by lift-off and served as an etch mask for Al2O3 wet etching and in ICP cryogenic dry etching. By using SF6/O2 plasma during inductively coupled plasma (ICP) cryogenic dry etching, micropillar tips were obtained. From the preliminary friction and wear data, the developed silicon cantilever sensor has been successfully used in 100 fast measurements of 5- mm-long standard artifact surface with a speed of 15 mm/s and forces of 60-100 μN. Moreover, the results yielded by the fabricated silicon cantilever sensor are in very good agreement with those of calibrated profilometer. These tactile sensors are targeted for use in high-aspect-ratio microform metrology.

Transport Powder and Liquid Samples by Surface Acoustic Waves

Science.gov (United States)

Bao, Xiaoqi; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Louyeh, Sahar

2009-01-01

Sample transport is an important requirement for In-situ analysis of samples in NASA planetary exploration missions. Tests have shown that powders or liquid drops on a surface can be transported by surface acoustic waves (SAW) that are generated on the surface using interdigital transducers. The phenomena were investigated experimentally and to generate SAWs interdigital electrodes were deposited on wafers of 128 deg rotated Y-cut LiNbO?. Transporting capability of the SAW device was tested using particles of various sizes and drops of various viscosities liquids. Because of different interaction mechanisms with the SAWs, the powders and the liquid drops were observed to move in opposite directions. In the preliminary tests, a speed of 180 mm/s was achieved for powder transportation. The detailed experimental setup and results are presented in this paper. The transporting mechanism can potentially be applied to miniaturize sample analysis system or " lab-on-chip" devices.

The impact of a fully idealised high speed train into a constrained fuel transport flask

International Nuclear Information System (INIS)

Dowler, H.J.

1985-05-01

The outcome of an accident involving a high speed train, travelling at 125 mph and impacting a stationary irradiated fuel transport flask is investigated. The case considered is that of a fully constrained flask and the power cars and carriages are fully idealised. A representation of the impact and an estimate of the resulting force-time curve experienced by the fuel flask are given. It is found that the peak force is not increased by the addition of coaches, but the time duration of the impact is lengthened. (author)

Research and new technologies in transportation. Vol. 1. High-speed railway systems: Maglev technology. Forschung und neue Technologien im Verkehr. Bd. 1. Schnellbahnsysteme: Magnetbandtechnolgie

Energy Technology Data Exchange (ETDEWEB)

1988-01-01

High-speed magnetic levitation technology opens up a new dimension for long-distance passenger transport with speeds ranging between ground travel and flying. The status of development and test results of the German TRANSRAPID magnetic levitation system and corresponding activities abroad will be reported on. Both the new vehicle technology of the TRANSRAPID 07 and results of application studies at home and abroad will be presented. High-speed magnetic railway technology - status and development perspectives; readiness for service, safety and reliability, application studies. The book comprises 11 papers read at the symposium on the subject of high-speed trains. 14 papers have been recorded separately in this database. (orig./HW).

Carbon Dioxide Mitigation Benefit of High-Speed Railway in Terms of Carbon Tax

Directory of Open Access Journals (Sweden)

Fu Yanbing

2013-01-01

Full Text Available This paper calculates the carbon dioxide mitigation benefit of high-speed railway based on the carbon dioxide tax policy. We define the carbon dioxide emission system boundary for high-speed railway in its whole life cycle and estimate the life cycle carbon dioxide inventories during its construction, application, and recovery stages. And then we establish a theoretical model to calculate the life cycle carbon dioxide mitigation quantity for high-speed railway when compared with road transport and then calculate its carbon dioxide mitigation benefit. The numerical example shows that the carbon dioxide mitigation benefit of high-speed railway is better than that of road transport from the whole life cycle perspective.

The economic effects of high speed rail investment

OpenAIRE

de Rus, Ginés

2008-01-01

The allocation of traffic between different transport modes follows transport user decisions which depend on the generalized cost of travel in the available alternatives. High Speed Rail (HSR) investment is a government decision with significant effects on the generalized cost of rail transport; and therefore on the modal split in corridors where private operators compete for traffic and charge prices close to total producer costs (infrastructure included). The rationale for HSR investment is...

High-speed microjet generation using laser-induced vapor bubbles

Science.gov (United States)

Oudalov, Nikolai; Tagawa, Yoshiyuki; Peters, Ivo; Visser, Claas-Willem; van der Meer, Devaraj; Prosperetti, Andrea; Sun, Chao; Lohse, Detlef

2011-11-01

The generation and evolution of microjets are studied both experimentally and numerically. The jets are generated by focusing a laser pulse into a microscopic capillary tube (~50 μm) filled with water-based red dye. A vapor bubble is created instantly after shooting the laser (<1 μs), sending out a shockwave towards the curved free surface at which the high-speed microjet forms. The process of jet formation is captured using high-speed recordings at 1.0 × 106 fps. The velocity of the microjets can reach speeds of ~850 m/s while maintaining a very sharp geometry. The high-speed recordings enable us to study the effect of several parameters on the jet velocity, e.g. the absorbed energy and the distance between the laser spot and the free surface.The results show a clear dependence on these variables, even for supersonic speeds. Comparisons with numerical simulations confirm the nature of these dependencies.

Water experiment of high-speed, free-surface, plane jet along concave wall

International Nuclear Information System (INIS)

Nakamura, Hideo; Ida, Mizuho; Kato, Yoshio; Maekawa, Hiroshi; Itoh, Kazuhiro; Kukita, Yutaka

1997-01-01

In the International Fusion Materials Irradiation Facility (IFMIF), an intense 14 MeV neutron beam will be generated in the high-speed liquid lithium (Li) plane jet target flowing along concave wall in vacuum. As part of the conceptual design activity (CDA) of the IFMIF, the stability of the plane liquid jet flow was studied experimentally with water in a well-defined channel geometry for non-heating condition. A two-dimensional double-reducer nozzle being newly proposed for the IFMIF target successfully provided a high-speed (≤ 17 m/s) stable water jet with uniform velocity distribution at the nozzle exit without flow separation in the nozzle. The free surface of the jet was covered by two-dimensional and/or three-dimensional waves, the size of which did not change much over the tested jet length of ∼130 mm. The jet velocity profile changed around the nozzle exit from uniform to that of free-vortex flow where the product of the radius of stream line and local velocity is constant in the jet thickness. The jet thickness increased immediately after exiting the nozzle because of the velocity profile change. The predicted jet thickness by a modified one-dimensional momentum model agreed with the data well. (author)

High-speed Maglev studies in Canada

International Nuclear Information System (INIS)

Atherton, D.L.; Eastham, A.R.

1974-01-01

This paper reports on Canadian studies of superconducting magnetic levitation and variable-speed linear synchronous motor propulsion for high-speed inter-city guided ground transport. Levitation is obtained by the interaction of vehicle-mounted superconducting magnets and the eddy currents induced in aluminium strip conductors on the guideway. Non-contact propulsion by linear synchronous motor (LSM) is obtained by using vehicle-borne superconducting magnets and powered guideway coils. A suggested guidance scheme uses a flat guideway with 'null-flux' loops overlying the LSM windings. The propulsion magnets interact with the loops and the edges of the levitation strips to provide lateral stabilization. The test facility is a 7.6m wheel, rotating with a peripheral speed of 33m/s. (author)

Using GPS-derived speed patterns for recognition of transport modes in adults.

Science.gov (United States)

Huss, Anke; Beekhuizen, Johan; Kromhout, Hans; Vermeulen, Roel

2014-10-11

Identification of active or sedentary modes of transport is of relevance for studies assessing physical activity or addressing exposure assessment. We assessed in a proof-of-principle study if speed as logged by GPSs could be used to identify modes of transport (walking, bicycling, and motorized transport: car, bus or train). 12 persons commuting to work walking, bicycling or with motorized transport carried GPSs for two commutes and recorded their mode of transport. We evaluated seven speed metrics: mean, 95th percentile of speed, standard deviation of the mean, rate-of-change, standardized-rate-of-change, acceleration and deceleration. We assessed which speed metric would best identify the transport mode using discriminant analyses. We applied cross validation and calculated agreement (Cohen's Kappa) between actual and derived modes of transport. Mode of transport was reliably classified whenever a person used a mode of transport for longer than one minute. Best results were observed when using the 95th percentile of speed, acceleration and deceleration (kappa 0.73). When we combined all motorized traffic into one category, kappa increased to 0.95. GPS-measured speed enable the identification of modes of transport. Given the current low costs of GPS devices and the built-in capacity of GPS tracking in most smartphones, the use of such devices in large epidemiological studies may facilitate the assessment of physical activity related to transport modes, or improve exposure assessment using automated travel mode detection.

High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

International Nuclear Information System (INIS)

Hihath, Sahar; Santala, Melissa K.; Campbell, Geoffrey; Benthem, Klaus van

2016-01-01

The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO_3 substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisition during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.

High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Hihath, Sahar [Department of Materials Science and Engineering, University of California, Davis, 1 Shields Ave., Davis, California 95616 (United States); Department of Physics, University of California, Davis, 1 Shields Ave., Davis, California 95616 (United States); Santala, Melissa K.; Campbell, Geoffrey [Materials Science Division, Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States); Benthem, Klaus van, E-mail: benthem@ucdavis.edu [Department of Materials Science and Engineering, University of California, Davis, 1 Shields Ave., Davis, California 95616 (United States)

2016-08-28

The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO{sub 3} substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisition during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.

Hydrogen tube vehicle for supersonic transport: 2. Speed and energy

Energy Technology Data Exchange (ETDEWEB)

Miller, Arnold R. [Vehicle Projects Inc and Supersonic Tubevehicle LLC, 200 Violet St, Suite 100, Golden, CO 80401 (United States)

2010-06-15

The central concept of a new idea in high-speed transport is that operation of a vehicle in a hydrogen atmosphere, because of the low density of hydrogen, would increase sonic speed by a factor of 3.8 and decrease drag by 15 relative to air. A hydrogen atmosphere requires that the vehicle operate within a hydrogen-filled tube or pipeline, which serves as a phase separator. The supersonic tube vehicle (STV) can be supersonic with respect to air outside the tube while remaining subsonic inside. It breathes hydrogen fuel for its propulsion fuel cells from the tube itself. This paper, second in a series on the scientific foundations of the supersonic tube vehicle, tests the hypothesis that the STV will be simultaneously fast and energy efficient by comparing its predicted speed and energy consumption with that of four long-haul passenger transport modes: road, rail, maglev, and air. The study establishes the speed ranking STV >> airplane > maglev > train > coach (intercity bus) and the normalized energy consumption ranking Airplane >> coach > maglev > train > STV. Consistent with the hypothesis, the concept vehicle is both the fastest and lowest energy consuming mode. In theory, the vehicle can cruise at Mach 2.8 while consuming less than half the energy per passenger of a Boeing 747 at a cruise speed of Mach 0.81. (author)

High efficiency heat transport and power conversion system for cascade

International Nuclear Information System (INIS)

Maya, I.; Bourque, R.F.; Creedon, R.L.; Schultz, K.R.

1985-02-01

The Cascade ICF reactor features a flowing blanket of solid BeO and LiAlO 2 granules with very high temperature capability (up to approx. 2300 K). The authors present here the design of a high temperature granule transport and heat exchange system, and two options for high efficiency power conversion. The centrifugal-throw transport system uses the peripheral speed imparted to the granules by the rotating chamber to effect granule transport and requires no additional equipment. The heat exchanger design is a vacuum heat transfer concept utilizing gravity-induced flow of the granules over ceramic heat exchange surfaces. A reference Brayton power cycle is presented which achieves 55% net efficiency with 1300 K peak helium temperature. A modified Field steam cycle (a hybrid Rankine/Brayton cycle) is presented as an alternate which achieves 56% net efficiency

Control of interior surface materials for speech privacy in high-speed train cabins.

Science.gov (United States)

Jang, H S; Lim, H; Jeon, J Y

2017-05-01

The effect of interior materials with various absorption coefficients on speech privacy was investigated in a 1:10 scale model of one high-speed train cabin geometry. The speech transmission index (STI) and privacy distance (r P ) were measured in the train cabin to quantify speech privacy. Measurement cases were selected for the ceiling, sidewall, and front and back walls and were classified as high-, medium- and low-absorption coefficient cases. Interior materials with high absorption coefficients yielded a low r P , and the ceiling had the largest impact on both the STI and r P among the interior elements. Combinations of the three cases were measured, and the maximum reduction in r P by the absorptive surfaces was 2.4 m, which exceeds the space between two rows of chairs in the high-speed train. Additionally, the contribution of the interior elements to speech privacy was analyzed using recorded impulse responses and a multiple regression model for r P using the equivalent absorption area. The analysis confirmed that the ceiling was the most important interior element for improving speech privacy. These results can be used to find the relative decrease in r P in the acoustic design of interior materials to improve speech privacy in train cabins. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

High wind speeds prevent formation of a distinct bacterioneuston community in the sea-surface microlayer.

Science.gov (United States)

Rahlff, Janina; Stolle, Christian; Giebel, Helge-Ansgar; Brinkhoff, Thorsten; Ribas-Ribas, Mariana; Hodapp, Dorothee; Wurl, Oliver

2017-05-01

The sea-surface microlayer (SML) at the boundary between atmosphere and hydrosphere represents a demanding habitat for bacteria. Wind speed is a crucial but poorly studied factor for its physical integrity. Increasing atmospheric burden of CO2, as suggested for future climate scenarios, may particularly act on this habitat at the air-sea interface. We investigated the effect of increasing wind speeds and different pCO2 levels on SML microbial communities in a wind-wave tunnel, which offered the advantage of low spatial and temporal variability. We found that enrichment of bacteria in the SML occurred solely at a U10 wind speed of ≤5.6 m s-1 in the tunnel and ≤4.1 m s-1 in the Baltic Sea. High pCO2 levels further intensified the bacterial enrichment in the SML during low wind speed. In addition, low wind speed and pCO2 induced the formation of a distinctive bacterial community as revealed by 16S rRNA gene fingerprints and influenced the presence or absence of individual taxonomic units within the SML. We conclude that physical stability of the SML below a system-specific wind speed threshold induces specific bacterial communities in the SML entailing strong implications for ecosystem functioning by wind-driven impacts on habitat properties, gas exchange and matter cycling processes. © FEMS 2017.

High-speed collision of copper nanoparticle with aluminum surface: Molecular dynamics simulation

Energy Technology Data Exchange (ETDEWEB)

Pogorelko, Victor V., E-mail: vik_ko83@mail.ru [Chelyabinsk State University, Bratiev Kashirinykh 129, 454001 Chelyabinsk (Russian Federation); South Ural State University (National Research University), Lenin Prospect 76, 454080 Chelyabinsk (Russian Federation); Mayer, Alexander E., E-mail: mayer@csu.ru [Chelyabinsk State University, Bratiev Kashirinykh 129, 454001 Chelyabinsk (Russian Federation); South Ural State University (National Research University), Lenin Prospect 76, 454080 Chelyabinsk (Russian Federation); Krasnikov, Vasiliy S., E-mail: vas.krasnikov@gmail.com [Chelyabinsk State University, Bratiev Kashirinykh 129, 454001 Chelyabinsk (Russian Federation); South Ural State University (National Research University), Lenin Prospect 76, 454080 Chelyabinsk (Russian Federation)

2016-12-30

Highlights: • High-speed nanoparticle impact induces shock waves and intensive plastic deformation. • Lattice orientation strongly influences on the deformation degree. • Plastic deformation goes through nucleation, growth and separation of semi-loops. • Medium impact energy and elevated temperature are optimal for high-quality coating. • High impact velocity and room temperature lead to plastic deformation and coating. - Abstract: We investigate the effect of the high-speed collision of copper nanoparticles with aluminum surface by means of molecular dynamic simulations. Studied diameter of nanoparticles is varied within the range 7.2–22 nm and the velocity of impact is equal to 500 or 1000 m/s. Dislocation analysis shows that a large quantity of dislocations is formed within the impact area. Overall length of dislocations is determined, first of all, by the impact velocity and by the size of incident copper nanoparticle, in other words, by the kinetic energy of the nanoparticle. Dislocations occupy the total volume of the impacted aluminum single crystal layer (40.5 nm in thickness) in the form of intertwined structure in the case of large kinetic energy of the incident nanoparticle. Decrease in the initial kinetic energy or increase in the layer thickness lead to restriction of the penetration depth of the dislocation net; formation of separate dislocation loops is observed in this case. Increase in the initial system temperature slightly raises the dislocation density inside the bombarded layer and considerably decreases the dislocation density inside the nanoparticle. The temperature increase also leads to a deeper penetration of the copper atoms inside the aluminum. Additional molecular dynamic simulations show that the deposited particles demonstrate a very good adhesion even in the case of the considered relatively large nanoparticles. Medium energy of the nanoparticles corresponding to velocity of about 500 m/s and elevated temperature of the

High-speed collision of copper nanoparticle with aluminum surface: Molecular dynamics simulation

International Nuclear Information System (INIS)

Pogorelko, Victor V.; Mayer, Alexander E.; Krasnikov, Vasiliy S.

2016-01-01

Highlights: • High-speed nanoparticle impact induces shock waves and intensive plastic deformation. • Lattice orientation strongly influences on the deformation degree. • Plastic deformation goes through nucleation, growth and separation of semi-loops. • Medium impact energy and elevated temperature are optimal for high-quality coating. • High impact velocity and room temperature lead to plastic deformation and coating. - Abstract: We investigate the effect of the high-speed collision of copper nanoparticles with aluminum surface by means of molecular dynamic simulations. Studied diameter of nanoparticles is varied within the range 7.2–22 nm and the velocity of impact is equal to 500 or 1000 m/s. Dislocation analysis shows that a large quantity of dislocations is formed within the impact area. Overall length of dislocations is determined, first of all, by the impact velocity and by the size of incident copper nanoparticle, in other words, by the kinetic energy of the nanoparticle. Dislocations occupy the total volume of the impacted aluminum single crystal layer (40.5 nm in thickness) in the form of intertwined structure in the case of large kinetic energy of the incident nanoparticle. Decrease in the initial kinetic energy or increase in the layer thickness lead to restriction of the penetration depth of the dislocation net; formation of separate dislocation loops is observed in this case. Increase in the initial system temperature slightly raises the dislocation density inside the bombarded layer and considerably decreases the dislocation density inside the nanoparticle. The temperature increase also leads to a deeper penetration of the copper atoms inside the aluminum. Additional molecular dynamic simulations show that the deposited particles demonstrate a very good adhesion even in the case of the considered relatively large nanoparticles. Medium energy of the nanoparticles corresponding to velocity of about 500 m/s and elevated temperature of the

Multiple component codes based generalized LDPC codes for high-speed optical transport.

Science.gov (United States)

Djordjevic, Ivan B; Wang, Ting

2014-07-14

A class of generalized low-density parity-check (GLDPC) codes suitable for optical communications is proposed, which consists of multiple local codes. It is shown that Hamming, BCH, and Reed-Muller codes can be used as local codes, and that the maximum a posteriori probability (MAP) decoding of these local codes by Ashikhmin-Lytsin algorithm is feasible in terms of complexity and performance. We demonstrate that record coding gains can be obtained from properly designed GLDPC codes, derived from multiple component codes. We then show that several recently proposed classes of LDPC codes such as convolutional and spatially-coupled codes can be described using the concept of GLDPC coding, which indicates that the GLDPC coding can be used as a unified platform for advanced FEC enabling ultra-high speed optical transport. The proposed class of GLDPC codes is also suitable for code-rate adaption, to adjust the error correction strength depending on the optical channel conditions.

Chip formation and surface integrity in high-speed machining of hardened steel

Science.gov (United States)

Kishawy, Hossam Eldeen A.

during cutting on the residual stresses. The machined specimens are also examined using x-ray diffraction technique to clarify the effect of different speeds, feeds and depths of cut as well as different edge preparations on the residual stress distribution beneath the machined surface. A reasonable agreement between the predicted and measured residual stress is obtained. The results obtained demonstrate the possibility of eliminating the existence of high tensile residual stresses in the workpiece surface by selecting the proper cutting conditions. The machined surfaces are examined using SEM to study the effect of different process parameters and edge preparations on the quality of the machined surface. The phenomenon of material side flow is investigated to clarify the mechanism of this phenomenon. The effect of process parameters and edge preparations on sub-surface deformation is also investigated.

High-Speed Surface Reconstruction of Flying Birds Using Structured Light

Science.gov (United States)

Deetjen, Marc; Lentink, David

2017-11-01

Birds fly effectively through complex environments, and in order to understand the strategies that enable them to do so, we need to determine the shape and movement of their wings. Previous studies show that even small perturbations in wing shape have dramatic aerodynamic effects, but these shape changes have not been quantified automatically at high temporal and spatial resolutions. Hence, we developed a custom 3D surface mapping method which uses a high-speed camera to view a grid of stripes projected onto a flying bird. Because the light is binary rather than grayscale, and each frame is separately analyzed, this method can function at any frame rate with sufficient light. The method is automated, non-invasive, and able to measure a volume by simultaneously reconstructing from multiple views. We use this technique to reconstruct the 3D shape of the surface of a parrotlet during flapping flight at 3200 fps. We then analyze key dynamic parameters such as wing twist and angle of attack, and compute aerodynamic parameters such as lift and drag. While this novel system is designed to quantify bird wing shape and motion, it is adaptable for tracking other objects such as quickly deforming fish, especially those which are difficult to reconstruct using other 3D tracking methods. The presenter needs to leave by 3 pm on the final day of the conference (11/21) in order to make his flight. Please account for this in the scheduling if possible by scheduling the presentation earlier in the day or a different day.

Influence of track surface on the equine superficial digital flexor tendon loading in two horses at high speed trot.

Science.gov (United States)

Crevier-Denoix, N; Pourcelot, P; Ravary, B; Robin, D; Falala, S; Uzel, S; Grison, A C; Valette, J P; Denoix, J M; Chateau, H

2009-03-01

Although track surfaces are a risk factor of tendon injuries, their effects on tendon loading at high speed are unknown. Using a noninvasive ultrasonic technique, it is now possible to evaluate the forces in the superficial digital flexor tendon (SDFT) in exercise conditions. To compare the effects of an all-weather waxed track (W) vs. a crushed sand track (S), on the SDFT loading in the trotter horse at high speed. Two trotter horses were equipped with the ultrasonic device (1 MHz ultrasonic probe, fixed on the palmar metacarpal area of the right forelimb). For each trial, data acquisition was made at 400 Hz and 10 consecutive strides were analysed. In each session, the 2 track surfaces were tested in a straight line. The speed was imposed at 10 m/s and recorded. The right forelimb was also equipped with a dynamometric horseshoe and skin markers. The horse was filmed with a high-speed camera (600 Hz); all recordings were synchronised. Statistical differences were tested using the GLM procedure (SAS; P < 0.05). Maximal tendon force was significantly lower on W compared with S. In addition to maximal force peaks around mid-stance, earlier peaks were observed, more pronounced on S than on W, at about 13% (horse 2) and 30% (both horses) of the stance phase. Comparison with kinematic data revealed that these early peaks were accompanied by plateaux in the fetlock angle-time chart. For high tendon forces, the tendon maximal loading rate was significantly lower on W than on S. CONCLUSIONS AND POTENTIAL CLINICAL RELEVANCE: The all-weather waxed track appears to induce a lesser and more gradual SDFT loading than crushed sand. The SDFT loading pattern at high speed trot suggests proximal interphalangeal joint movements during limb loading.

High speed railway track dynamics models, algorithms and applications

CERN Document Server

Lei, Xiaoyan

2017-01-01

This book systematically summarizes the latest research findings on high-speed railway track dynamics, made by the author and his research team over the past decade. It explores cutting-edge issues concerning the basic theory of high-speed railways, covering the dynamic theories, models, algorithms and engineering applications of the high-speed train and track coupling system. Presenting original concepts, systematic theories and advanced algorithms, the book places great emphasis on the precision and completeness of its content. The chapters are interrelated yet largely self-contained, allowing readers to either read through the book as a whole or focus on specific topics. It also combines theories with practice to effectively introduce readers to the latest research findings and developments in high-speed railway track dynamics. It offers a valuable resource for researchers, postgraduates and engineers in the fields of civil engineering, transportation, highway & railway engineering.

Development of Industrial High-Speed Transfer Parallel Robot

International Nuclear Information System (INIS)

Kim, Byung In; Kyung, Jin Ho; Do, Hyun Min; Jo, Sang Hyun

2013-01-01

Parallel robots used in industry require high stiffness or high speed because of their structural characteristics. Nowadays, the importance of rapid transportation has increased in the distribution industry. In this light, an industrial parallel robot has been developed for high-speed transfer. The developed parallel robot can handle a maximum payload of 3 kg. For a payload of 0.1 kg, the trajectory cycle time is 0.3 s (come and go), and the maximum velocity is 4.5 m/s (pick amp, place work, adept cycle). In this motion, its maximum acceleration is very high and reaches approximately 13g. In this paper, the design, analysis, and performance test results of the developed parallel robot system are introduced

The effect of product quality on the integrity of advanced surface engineering treatments applied to high speed steel circular saw blades

International Nuclear Information System (INIS)

Bradbury, S.R.; Sarwar, M.

1996-01-01

Advanced surface engineering technologies have been successfully applied to high speed steel drills and carbide single-point cutting tools, but, as yet, limited benefits have been realized when applying the same technologies to multi-point cutting tools of commercial quality. This paper discusses the factors that have limited the benefits of advanced surface engineering treatments when applied to high speed steel circular saw blades. Common manufacturing defects have been identified on the teeth of the blades. Tests which evaluate the blade performance throughout its useful life and examination by scanning electron microscopy (SEM) have shown that these defects adversely affect the performance and wear resistance of surface engineered blades. Further investigations suggest that significant improvements in coating integrity can be achieved through the careful preparation of the substrate surface and refinement of the cutting edge geometry prior to treatment. For this application, the need for refinement and enhancement of current manufacturing practices is demonstrated if the full benefits of advanced surface engineering are to be realized. (orig.)

Additional Development and Systems Analyses of Pneumatic Technology for High Speed Civil Transport Aircraft

Science.gov (United States)

Englar, Robert J.; Willie, F. Scott; Lee, Warren J.

1999-01-01

In the Task I portion of this NASA research grant, configuration development and experimental investigations have been conducted on a series of pneumatic high-lift and control surface devices applied to a generic High Speed Civil Transport (HSCT) model configuration to determine their potential for improved aerodynamic performance, plus stability and control of higher performance aircraft. These investigations were intended to optimize pneumatic lift and drag performance; provide adequate control and longitudinal stability; reduce separation flowfields at high angle of attack; increase takeoff/climbout lift-to-drag ratios; and reduce system complexity and weight. Experimental aerodynamic evaluations were performed on a semi-span HSCT generic model with improved fuselage fineness ratio and with interchangeable plain flaps, blown flaps, pneumatic Circulation Control Wing (CCW) high-lift configurations, plain and blown canards, a novel Circulation Control (CC) cylinder blown canard, and a clean cruise wing for reference. Conventional tail power was also investigated for longitudinal trim capability. Also evaluated was unsteady pulsed blowing of the wing high-lift system to determine if reduced pulsed mass flow rates and blowing requirements could be made to yield the same lift as that resulting from steady-state blowing. Depending on the pulsing frequency applied, reduced mass flow rates were indeed found able to provide lift augmentation at lesser blowing values than for the steady conditions. Significant improvements in the aerodynamic characteristics leading to improved performance and stability/control were identified, and the various components were compared to evaluate the pneumatic potential of each. Aerodynamic results were provided to the Georgia Tech Aerospace System Design Lab. to conduct the companion system analyses and feasibility study (Task 2) of theses concepts applied to an operational advanced HSCT aircraft. Results and conclusions from these

Florida intercity high speed rail passenger service

Energy Technology Data Exchange (ETDEWEB)

Najafi, F.T.; Watford, S.; Moore, G.; Des, A. [Florida Univ., Gainesville, FL (United States). Dept. of Civil Engineering

1997-10-01

Plans for a new high-speed rail (HSR) transportation system in Florida were reviewed. HSR is believed to be the least expensive, most energy-efficient and least environmentally harmful alternative to air and highway travel. The system in Florida will be used as a case study to determine its overall impact on the environment, people and economy. The 300-plus mile system will move travelers at speeds of over 200 mph between Miami, Orlando, and Tampa. The study will identify the impacts of a HSR system on existing transportation networks, environment, energy, growth and growth distribution, safety, economy, travel time, and tourism. Transportation problems and the innovative mechanisms needed to realize the joint public and private venture approach to planning, locating, permitting, managing, financing, constructing and maintaining an inter-regional HSR line for the state were studied. The all-electric train would greatly help the environment in two ways: (1) zero emissions from the train itself, and (2) the reduction of trips by automobile and aircraft would reduce the amount of fuel and energy being used. 4 refs., 1 fig.

High speed cine film studies of plasma behaviour and plasma surface interactions in tokamaks

International Nuclear Information System (INIS)

Goodall, D.H.J.

1982-01-01

High speed cine photography is a useful diagnostic aid for studying plasma behaviour and plasma surface interactions. Several workers have filmed discharges in tokamaks including ASDEX, DITE, DIVA, ISX, JFT2, TFR and PLT. These films are discussed and examples given of the observed phenomena which include plasma limiter interactions, diverted discharges, disruptions, magnetic islands and moving glowing objects often known as 'UFOs'. Examples of plasma structures in ASDEX and DITE not previously published are also given. The paper also reports experiments in DITE to determine the origin of UFOs. (orig.)

Environmental risks of high-speed railway in China: Public participation, perception and trust

NARCIS (Netherlands)

He, G.; Mol, A.P.J.; Zhang, L.; Lu, Y.

2015-01-01

Two decades ago China entered an era with rapid expansion of transport infrastructure. In an ambitious plan on high-speed railway development, China plans to have the longest high-speed railway network by 2020. Social concerns and anxiety with the adverse environmental and social risks and impacts

Numerical Study of High-Speed Droplet Impact on Surfaces and its Physical Cleaning Effects

Science.gov (United States)

Kondo, Tomoki; Ando, Keita

2015-11-01

Spurred by the demand for cleaning techniques of low environmental impact, one favors physical cleaning that does not rely on any chemicals. One of the promising candidates is based on water jets that often involve fission into droplet fragments and collide with target surfaces to which contaminant particles (often micron-sized or even smaller) stick. Hydrodynamic force (e.g., shearing and lifting) arising from the droplet impact will play a role to remove the particles, but its detailed mechanism is still unknown. To explore the role of high-speed droplet impact in physical cleaning, we solve compressible Navier-Stokes equations with a finite volume method that is designed to capture both shocks and material interfaces in accurate and robust manners. Water hammer and shear flow accompanied by high-speed droplet impact at a rigid wall is simulated to evaluate lifting force and rotating torque, which are relevant to the application of particle removal. For the simulation, we use the numerical code recently developed by Computational Flow Group lead by Tim Colonius at Caltech. The first author thanks Jomela Meng for her help in handling the code during his stay at Caltech.

Visualization of Projectile Flying at High Speed in Dusty Atmosphere

Science.gov (United States)

Masaki, Chihiro; Watanabe, Yasumasa; Suzuki, Kojiro

2017-10-01

Considering a spacecraft that encounters particle-laden environment, such as dust particles flying up over the regolith by the jet of the landing thruster, high-speed flight of a projectile in such environment was experimentally simulated by using the ballistic range. At high-speed collision of particles on the projectile surface, they may be reflected with cracking into smaller pieces. On the other hand, the projectile surface will be damaged by the collision. To obtain the fundamental characteristics of such complicated phenomena, a projectile was launched at the velocity up to 400 m/s and the collective behaviour of particles around projectile was observed by the high-speed camera. To eliminate the effect of the gas-particle interaction and to focus on only the effect of the interaction between the particles and the projectile's surface, the test chamber pressure was evacuated down to 30 Pa. The particles about 400μm diameter were scattered and formed a sheet of particles in the test chamber by using two-dimensional funnel with a narrow slit. The projectile was launched into the particle sheet in the tangential direction, and the high-speed camera captured both projectile and particle motions. From the movie, the interaction between the projectile and particle sheet was clarified.

High speed atom source

International Nuclear Information System (INIS)

Hoshino, Hitoshi.

1990-01-01

In a high speed atom source, since the speed is not identical between ions and electrons, no sufficient neutralizing effect for ionic rays due to the mixing of the ionic rays and the electron rays can be obtained failing to obtain high speed atomic rays at high density. In view of the above, a speed control means is disposed for equalizing the speed of ions forming ionic rays and the speed of electrons forming electron rays. Further, incident angle of the electron rays and/or ionic rays to a magnet or an electrode is made variable. As a result, the relative speed between the ions and the electrons to the processing direction is reduced to zero, in which the probability of association between the ions and the electrons due to the coulomb force is increased to improve the neutralizing efficiency to easily obtain fine and high density high speed electron rays. Further, by varying the incident angle, a track capable of obtaining an ideal mixing depending on the energy of the neutralized ionic rays is formed. Since the high speed electron rays has such high density, they can be irradiated easily to the minute region of the specimen. (N.H.)

Noisiness of the Surfaces on Low-Speed Roads

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Wladyslaw Gardziejczyk

2016-03-01

Full Text Available Traffic noise is a particular threat to the environment in the vicinity of roads. The level of the noise is influenced by traffic density and traffic composition, as well as vehicle speed and the type of surface. The article presents the results of studies on tire/road noise from passing vehicles at a speed of 40–80 kph, carried out by using the statistical pass-by method (SPB, on seven surfaces with different characteristics. It has been shown that increasing the speed from 40 kph to 50 kph contributes to the increase in the maximum A-weighted sound pressure level by about 3 dB, regardless of the type of surface. For larger differences in speed (30 kph–40 kph increase in noise levels reaches values about 10 dB. In the case of higher speeds, this increase is slightly lower. In this article, special attention is paid to the noisiness from surfaces made of porous asphalt concrete (PAC, BBTM (thin asphalt layer, and stone mastic asphalt (SMA with a maximum aggregate size of 8 mm and 5 mm. It has also been proved that surfaces of porous asphalt concrete, within two years after the commissioning, significantly contribute to a reduction of the maximum level of noise in the streets and roads with lower speed of passing cars. Reduction of the maximum A-weighted sound pressure level of a statistical car traveling at 60 kph reaches values of up to about 6 dB, as compared with the SMA11. Along with the exploitation of the road, air voids in the low-noise surface becomes clogged and acoustic properties of the road decrease to a level similar to standard asphalt.

Study of surface integrity AISI 4140 as result of hard, dry and high speed machining using CBN

Science.gov (United States)

Ginting, B.; Sembiring, R. W.; Manurung, N.

2017-09-01

The concept of hard, dry and high speed machining can be combined, to produce high productivity, with lower production costs in manufacturing industry. Hard lathe process can be a solution to reduce production time. In lathe hard alloy steels reported problems relating to the integrity of such surface roughness, residual stress, the white layer and the surface integrity. AISI 4140 material is used for high reliable hydraulic system components. This material includes in cold work tool steel. Consideration election is because this material is able to be hardened up to 55 HRC. In this research, the experimental design using CCD model fit with three factors, each factor is composed of two levels, and six central point, experiments were conducted with 1 replications. The experimental design research using CCD model fit.

Investigation of new vehicle detectors for high-speed signalized intersections.

Science.gov (United States)

2015-09-01

Early indications from the use of the newest vehicle detectors for high-speed signalized intersections : suggested that they perform well as replacements for the Texas Department of Transportations : (TxDOTs) legacy systems, but this early conc...

Structural and technological formation of surface nanostructured Ti-Ni-Mo layers by high-speed gas-flame spraying

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Blednova Zhesfina

2015-01-01

Full Text Available The article covers a complex method of forming surface-modified layers using materials with shape memory effect (SME based on TiNiMo including pre-grinding and mechanical activation of the coating material, high-speed gas-flame spraying of Ni adhesive layer and subsequent TiNiMo spraying with molybdenum content up to 2%, thermal and thermomechanical processing in a single technological cycle. This allowed forming nanostructured surface layers with a high level of functional mechanical and performance properties. We defined control parameters of surface steel modification using material with shape memory effect based on TiNiMo, which monitor the structural material state, both at the stage of spraying, and during subsequent combined treatment, which allows affecting purposefully on the functional properties of the SME surface layer. Test results of samples before coating and after surface modification with TiNiMo in the seawater indicate that surface modification brings to a slower damage accumulation and to increase of steel J91171 endurance limit in seawater by 45%. Based on complex metallophysical research of surface layers we obtained new data about nano-sized composition “steel - Ni - TiNiMo”.

Social exclusion and high speed rail: The case study of Spain

Energy Technology Data Exchange (ETDEWEB)

Pagliara, F.; Menicocci, F.; Vassallo, J.M.; Gomez, J.

2016-07-01

Very few contributions in the literature have dealt with the issue of social exclusion related to High Speed Rail systems. The objective of this manuscript is to understand what are the factors excluding users from choosing High Speed Rail services considering as case study Spain. For this purpose, a Revealed Preference survey was employed in November and December 2015. A questionnaire was submitted to users of the Spanish transport systems travelling for long distance-journeys. The aim was that of investigating their perception of High Speed Rail system and the factors inhibiting passengers or excluding them from its use. Data about their socioeconomic characteristics were collected as well. The main result of the survey has been that a relationship between social exclusion and High Speed Rail in Spain is present, especially in terms of geographical exclusion. (Author)

Technology and human purpose: the problem of solids transport on the Earth's surface

Science.gov (United States)

Haff, P. K.

2012-11-01

Displacement of mass of limited deformability ("solids") on the Earth's surface is opposed by friction and (the analog of) form resistance - impediments relaxed by rotational motion, self-powering of mass units, and transport infrastructure. These features of solids transport first evolved in the biosphere prior to the emergence of technology, allowing slope-independent, diffusion-like motion of discrete objects as massive as several tons, as illustrated by animal foraging and movement along game trails. However, high-energy-consumption technology powered by fossil fuels required a mechanism that could support fast advective transport of solids, i.e., long-distance, high-volume, high-speed, unidirectional, slope-independent transport across the land surface of materials like coal, containerized fluids, minerals, and economic goods. Pre-technology nature was able to sustain regional- and global-scale advection only in the limited form of piggybacking on geophysical flows of water (river sediment) and air (dust). The appearance of a mechanism for sustained advection of solids independent of fluid flows and gravity appeared only upon the emergence of human purpose. Purpose enables solids advection by, in effect, simulating a continuous potential gradient, otherwise lacking, between discrete and widely separated fossil-fuel energy sources and sinks. Invoking purpose as a mechanism in solids advection is an example of the need to import anthropic principles and concepts into the language and methodology of modern Earth system dynamics. As part of the emergence of a generalized solids advection mechanism, several additional transport requirements necessary to the function of modern large-scale technological systems were also satisfied. These include spatially accurate delivery of advected payload, targetability to essentially arbitrarily located destinations (such as cities), and independence of structure of advected payload from transport mechanism. The latter property

Design and applications of a pneumatic accelerator for high speed punching

International Nuclear Information System (INIS)

Yaldiz, Sueleyman; Saglam, Haci; Unsacar, Faruk; Isik, Hakan

2007-01-01

High speed forming is an important production method that requires specially designed HERF (high energy rate forming) machines. Most of the HERF machines are devices that consist of a system in which energy is stored and a differential piston mechanism is used to release the energy at high rate. In order to eliminate the usage of specially designed HERF machines and to obtain the high speed forming benefits, the accelerator which can be adapted easily onto conventional presses has been designed and manufactured in this study. The designed energy accelerator can be incorporated into mechanical press to convert the low speed operation into high-speed operation of a hammer. Expectations from this work are reduced distortion rates, increased surface quality and precise dimensions in metal forming operations. From the performance test, the accelerator is able to achieve high speed and energy which require for high speed blanking of thick sheet metals

Cutting force model for high speed machining process

International Nuclear Information System (INIS)

Haber, R. E.; Jimenez, J. E.; Jimenez, A.; Lopez-Coronado, J.

2004-01-01

This paper presents cutting force-based models able to describe a high speed machining process. The model considers the cutting force as output variable, essential for the physical processes that are taking place in high speed machining. Moreover, this paper shows the mathematical development to derive the integral-differential equations, and the algorithms implemented in MATLAB to predict the cutting force in real time MATLAB is a software tool for doing numerical computations with matrices and vectors. It can also display information graphically and includes many toolboxes for several research and applications areas. Two end mill shapes are considered (i. e. cylindrical and ball end mill) for real-time implementation of the developed algorithms. the developed models are validated in slot milling operations. The results corroborate the importance of the cutting force variable for predicting tool wear in high speed machining operations. The developed models are the starting point for future work related with vibration analysis, process stability and dimensional surface finish in high speed machining processes. (Author) 19 refs

On the spectrum of the one-speed slab-geometry discrete ordinates operator in neutron transport theory

International Nuclear Information System (INIS)

Abreu, Marcos Pimenta de

1998-01-01

We describe a numerical method applied to the first-order form of one-speed slab-geometry discrete ordinates equations modelling time-independent neutron transport problems with anisotropic scattering, with no interior source and defined in a nonmultiplying homogeneous host medium. Our numerical method is concerned with the generation of the spectrum and of a vector basis for the null space of the one-speed slab-geometry discrete ordinates operator. Moreover, it allows us to overcome the difficulties introduced in previous methods by anisotropic scattering and by angular quadrature sets of high order. To illustrate the positive features of our numerical method, we present numerical results for one-speed slab-geometry neutron transport model problems with anisotropic scattering

The Effects of Gouge Accumulation on High Speed Rock Friction

Science.gov (United States)

Barbery, M. R.; Chester, F. M.; Chester, J. S.; Saber, O.

2016-12-01

Previous experiments demonstrate that a significant reduction in the coefficient of sliding friction typically occurs as sliding velocity approaches seismic slip rates and that weakening may reflect flash heating of surface contacts. Experiments also show differences in the weakening behavior of bare rock and gouge-lined surfaces across different rock types. We conducted high-speed velocity-step (VS) experiments on ground surfaces of granite (Westerly) and quartzite (Sioux) using a double-direct shear (DDS) configuration, with a sliding area of 75cm2, to investigate the effects of gouge generation and accumulation on frictional weakening behavior. Sliding surface temperatures were measured using a high-speed infrared camera. Experiments were conducted at 7-9 MPa normal stress and achieved VS from 1 mm/s up to 1 m/s at high acceleration (100g) over a small distance ( 2 mm), and with sustained high-speed sliding for 30 mm. Successive experiments were run without disassembling the blocks or disturbing the sliding surfaces to generate and accumulate gouge for cumulative displacements up to 0.5 m. Locally high temperatures were observed correlating to corrugated structures within the gouge. For VS tests on bare granite, we observed an abrupt decrease in the coefficient of friction from 0.7 at quasi-static slip rates to 0.5 at m/s slip rates, and a typical weakening distance, dc, of 3 mm. This observation is consistent with rotary shear experiments conducted at similar displacements, accelerations, and sliding velocities. With the accumulation of gouge along the sliding surface, dc progressively increases to 2 cm. In contrast, VS tests on bare quartzite produce an abrupt increase in friction, from 0.65 to 0.7 within 1 mm of slip, followed by gradual weakening for the duration of high-speed sliding. With the accumulation of quartz gouge, similar behavior is observed, but with a slightly greater magnitude of strengthening. The results for quartzite are unlike those

System Analyses of Pneumatic Technology for High Speed Civil Transport Aircraft

Science.gov (United States)

Mavris, Dimitri N.; Tai, Jimmy C.; Kirby, Michelle M.; Roth, Bryce A.

1999-01-01

The primary aspiration of this study was to objectively assess the feasibility of the application of a low speed pneumatic technology, in particular Circulation Control (CC) to an HSCT concept. Circulation Control has been chosen as an enabling technology to be applied on a generic High Speed Civil Transport (HSCT). This technology has been proven for various subsonic vehicles including flight tests on a Navy A-6 and computational application on a Boeing 737. Yet, CC has not been widely accepted for general commercial fixed-wing use but its potential has been extensively investigated for decades in wind tunnels across the globe for application to rotorcraft. More recently, an experimental investigation was performed at Georgia Tech Research Institute (GTRI) with application to an HSCT-type configuration. The data from those experiments was to be applied to a full-scale vehicle to assess the impact from a system level point of view. Hence, this study attempted to quantitatively assess the impact of this technology to an HSCT. The study objective was achieved in three primary steps: 1) Defining the need for CC technology; 2) Wind tunnel data reduction; 3) Detailed takeoff/landing performance assessment. Defining the need for the CC technology application to an HSCT encompassed a preliminary system level analysis. This was accomplished through the utilization of recent developments in modern aircraft design theory at Aerospace Systems Design Laboratory (ASDL). These developments include the creation of techniques and methods needed for the identification of technical feasibility show stoppers. These techniques and methods allow the designer to rapidly assess a design space and disciplinary metric enhancements to enlarge or improve the design space. The takeoff and landing field lengths were identified as the concept "show-stoppers". Once the need for CC was established, the actual application of data and trends was assessed. This assessment entailed a reduction of the

High-Speed Semiconductor Vertical-Cavity Surface-Emitting Lasers for Optical Data-Transmission Systems (Review)

Science.gov (United States)

Blokhin, S. A.; Maleev, N. A.; Bobrov, M. A.; Kuzmenkov, A. G.; Sakharov, A. V.; Ustinov, V. M.

2018-01-01

The main problems of providing a high-speed operation semiconductor lasers with a vertical microcavity (so-called "vertical-cavity surface-emitting lasers") under amplitude modulation and ways to solve them have been considered. The influence of the internal properties of the radiating active region and the electrical parasitic elements of the equivalent circuit of lasers are discussed. An overview of approaches that lead to an increase of the cutoff parasitic frequency, an increase of the differential gain of the active region, the possibility of the management of mode emission composition and the lifetime of photons in the optical microcavities, and reduction of the influence of thermal effects have been presented. The achieved level of modulation bandwidth of ˜30 GHz is close to the maximum achievable for the classical scheme of the direct-current modulation, which makes it necessary to use a multilevel modulation format to further increase the information capacity of optical channels constructed on the basis of vertical-cavity surface-emitting lasers.

Surface Roughness Optimization Using Taguchi Method of High Speed End Milling For Hardened Steel D2

Science.gov (United States)

Hazza Faizi Al-Hazza, Muataz; Ibrahim, Nur Asmawiyah bt; Adesta, Erry T. Y.; Khan, Ahsan Ali; Abdullah Sidek, Atiah Bt.

2017-03-01

The main challenge for any manufacturer is to achieve higher quality of their final products with maintains minimum machining time. In this research final surface roughness analysed and optimized with maximum 0.3 mm flank wear length. The experiment was investigated the effect of cutting speed, feed rate and depth of cut on the final surface roughness using D2 as a work piece hardened to 52-56 HRC, and coated carbide as cutting tool with higher cutting speed 120-240 mm/min. The experiment has been conducted using L9 design of Taguchi collection. The results have been analysed using JMP software.

High-speed centrifugation induces aggregation of extracellular vesicles.

Science.gov (United States)

Linares, Romain; Tan, Sisareuth; Gounou, Céline; Arraud, Nicolas; Brisson, Alain R

2015-01-01

Plasma and other body fluids contain cell-derived extracellular vesicles (EVs), which participate in physiopathological processes and have potential biomedical applications. In order to isolate, concentrate and purify EVs, high-speed centrifugation is often used. We show here, using electron microscopy, receptor-specific gold labelling and flow cytometry, that high-speed centrifugation induces the formation of EV aggregates composed of a mixture of EVs of various phenotypes and morphologies. The presence of aggregates made of EVs of different phenotypes may lead to erroneous interpretation concerning the existence of EVs harbouring surface antigens from different cell origins.

High-speed centrifugation induces aggregation of extracellular vesicles

Directory of Open Access Journals (Sweden)

Romain Linares

2015-12-01

Full Text Available Plasma and other body fluids contain cell-derived extracellular vesicles (EVs, which participate in physiopathological processes and have potential biomedical applications. In order to isolate, concentrate and purify EVs, high-speed centrifugation is often used. We show here, using electron microscopy, receptor-specific gold labelling and flow cytometry, that high-speed centrifugation induces the formation of EV aggregates composed of a mixture of EVs of various phenotypes and morphologies. The presence of aggregates made of EVs of different phenotypes may lead to erroneous interpretation concerning the existence of EVs harbouring surface antigens from different cell origins.

FORECASTING OF PASSENGER TRAFFIC UPON IMPLEMENTATION OF HIGH-SPEED RUNNING

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M. B. Kurhan

2017-02-01

Full Text Available Purpose. Forecasting of passenger traffic flows in the future is an essential and integral part of the complex process of designing of high-speed network (HSN. HSN direction and its parameters are determined by the volume of passenger traffic, the estimated value of which depends on the economic performance of the country, as well as the material status of citizens living in HSN concentration area, transport mobility of population, development of competing modes of transport and so on. The purpose of this work is to analyse the existing methods of passenger traffic forecasting, to evaluate errors of the existing models concerning determination of traffic volumes and to specify the scientific approach to the development of high-speed rail transport in Ukraine. Methodology. The existing forecasting methods are reduced to the following ones: Delphi approach, extrapolation method, factor and correlation analysis, simulation method. The method described in this paper is based on scientific approaches such as analysis – a comprehensive and detailed study of various aspects of the known forecasting methods, comparing of existing methods for establishing differences and similarities, as well as deduction – use of general knowledge to get the new particular one. Thus, the unified indicators determined for the country as a whole, such as gross domestic product, national income, total population and others cannot be used to forecast the traffic flow on specific areas of HSN construction. Therefore, it is necessary to move from the overall forecast to traffic volume forecast on particular direction. Findings. The conclusions are derived from the analysis of different approaches and methods of passenger flow forecasting. It is proposed to create typical techniques of traffic flow forecasting using modern mathematical methods that would allow avoiding unreasonable decisions and shortening project development time. The resulting recommendations will help

High speed cutting of AZ31 magnesium alloy

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Liwei Lu

2016-06-01

Full Text Available Using LBR-370 numerical control lathe, high speed cutting was applied to AZ31 magnesium alloy. The influence of cutting parameters on microstructure, surface roughness and machining hardening were investigated by using the methods of single factor and orthogonal experiment. The results show that the cutting parameters have an important effect on microstructure, surface roughness and machine hardening. The depth of stress layer, roughness and hardening present a declining tendency with the increase of the cutting speed and also increase with the augment of the cutting depth and feed rate. Moreover, we established a prediction model of the roughness, which has an important guidance on actual machining process of magnesium alloy.

Characteristics of Speed Line Cutter and Fringe Analysis of Workpiece Surface

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Shuai Wang

2014-02-01

Full Text Available Easy to operate, speed line cutter has a high machining cost performance, so is very popular among the majority of users. The precision of guide rails, screws and nuts used in most of the machines is not high, and the machine control cannot compensate for the screw pitch error, clearance during the transmission and machining error due to electrode wear. Furthermore, control signal may also be lost in control process. The development of speed line cutter focuses on the quality and machining stability of CNC speed line cutter. This article makes an analysis about the impact of machine’s inherent characteristics on machining workpiece surface, and concludes that analysis shall be made on the irregular fringe, therefore to heighten the machining precision.

Atmospheric Ionizing Radiation and the High Speed Civil Transport. Chapter 1

Science.gov (United States)

Maiden, D. L.; Wilson, J. W.; Jones, I. W.; Goldhagen, P.

2003-01-01

Atmospheric ionizing radiation is produced by extraterrestrial radiations incident on the Earth's atmosphere. These extraterrestrial radiations are of two sources: ever present galactic cosmic rays with origin outside the solar system and transient solar particle events that are at times very intense events associated with solar activity lasting several hours to a few days. Although the galactic radiation penetrating through the atmosphere to the ground is low in intensity, the intensity is more than two orders of magnitude greater at commercial aircraft altitudes. The radiation levels at the higher altitudes of the High Speed Civil Transport (HSCT) are an additional factor of two higher. Ionizing radiation produces chemically active radicals in biological tissues that alter the cell function or result in cell death. Protection standards against low levels of ionizing radiation are based on limitation of excess cancer mortality or limitation of developmental injury resulting in permanent damage to the offspring during pregnancy. The crews of commercial air transport operations are considered as radiation workers by the EPA, the FAA, and the International Commission on Radiological Protection (ICRP). The annual exposures of aircrews depend on the latitudes and altitudes of operation and flight time. Flight hours have significantly increased since deregulation of the airline industry in the 1980's. The FAA estimates annual subsonic aircrew exposures to range from 0.2 to 9.1 mSv compared to 0.5 mSv exposure of the average nuclear power plant worker in the nuclear industry. The commercial aircrews of the HSCT may receive exposures above recently recommended allowable limits for even radiation workers if flying their allowable number of flight hours. An adequate protection philosophy for background exposures in HSCT commercial airtraffic cannot be developed at this time due to current uncertainty in environmental levels. In addition, if a large solar particle event

Prospects of China's High-speed Railroad considering the Debate on "Maglev" and "On-the-Trail" Contributions

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Run Sha

2012-10-01

Full Text Available Considering the fierce debate on whether "maglev" or"on-the-trail" system should be applied to China's first high-speed railroad, this paper makes prospects about China's high--speed railroads. As at the initial stage, careful considerationsshould be given to the framework of China's high-speed railroads.Combining China's specific national conditions, the paperdemonstrates that maglev train can be well applied in theeast and the regions of the middle and lower reaches of theYangtze River where there is developed economy, lwge anddense population, limited land use, concentrated big cities andrail transport shortage. The maglev system is the world's mostadvanced technology, China should take the best to catch upwith the world in this transportation field.

Yonjung High-Speed Railway Bridge Assessment Using Output-Only Structural Health Monitoring Measurements under Train Speed Changing

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Mosbeh R. Kaloop

2016-01-01

Full Text Available Yonjung Bridge is a hybrid multispan bridge that is designed to transport high-speed trains (HEMU-430X with maximum operating speed of 430 km/h. The bridge consists of simply supported prestressed concrete (PSC and composite steel girders to carry double railway tracks. The structural health monitoring system (SHM is designed and installed to investigate and assess the performance of the bridge in terms of acceleration and deformation measurements under different speeds of the passing train. The SHM measurements are investigated in both time and frequency domains; in addition, several identification models are examined to assess the performance of the bridge. The drawn conclusions show that the maximum deflection and acceleration of the bridge are within the design limits that are specified by the Korean and European codes. The parameters evaluation of the model identification depicts the quasistatic and dynamic deformations of PSC and steel girders to be different and less correlated when higher speeds of the passing trains are considered. Finally, the variation of the frequency content of the dynamic deformations of the girders is negligible when high speeds are considered.

Control of Ambipolar Transport in SnO Thin-Film Transistors by Back-Channel Surface Passivation for High Performance Complementary-like Inverters.

Science.gov (United States)

Luo, Hao; Liang, Lingyan; Cao, Hongtao; Dai, Mingzhi; Lu, Yicheng; Wang, Mei

2015-08-12

For ultrathin semiconductor channels, the surface and interface nature are vital and often dominate the bulk properties to govern the field-effect behaviors. High-performance thin-film transistors (TFTs) rely on the well-defined interface between the channel and gate dielectric, featuring negligible charge trap states and high-speed carrier transport with minimum carrier scattering characters. The passivation process on the back-channel surface of the bottom-gate TFTs is indispensable for suppressing the surface states and blocking the interactions between the semiconductor channel and the surrounding atmosphere. We report a dielectric layer for passivation of the back-channel surface of 20 nm thick tin monoxide (SnO) TFTs to achieve ambipolar operation and complementary metal oxide semiconductor (CMOS) like logic devices. This chemical passivation reduces the subgap states of the ultrathin channel, which offers an opportunity to facilitate the Fermi level shifting upward upon changing the polarity of the gate voltage. With the advent of n-type inversion along with the pristine p-type conduction, it is now possible to realize ambipolar operation using only one channel layer. The CMOS-like logic inverters based on ambipolar SnO TFTs were also demonstrated. Large inverter voltage gains (>100) in combination with wide noise margins are achieved due to high and balanced electron and hole mobilities. The passivation also improves the long-term stability of the devices. The ability to simultaneously achieve field-effect inversion, electrical stability, and logic function in those devices can open up possibilities for the conventional back-channel surface passivation in the CMOS-like electronics.

Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

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Shih-Chen Shi

2016-07-01

Full Text Available The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC, hydroxypropyl methylcellulose phthalate (HPMCP, and hydroxypropyl methylcellulose acetate succinate (HPMCAS film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate promising anti-corrosion performance of HPMC and HPMCP. With increasing film thickness, both materials reveal improvement in corrosion inhibition. Moreover, because of a hydrophobic surface and lower moisture content, HPMCP shows better anti-corrosion performance than HPMCAS. The study is of certain importance for designing green corrosion inhibitors of high speed steel surfaces by the use of biopolymer derivatives.

The high speed interconnect system architecture and operation

Science.gov (United States)

Anderson, Steven C.

The design and operation of a fiber-optic high-speed interconnect system (HSIS) being developed to meet the requirements of future avionics and flight-control hardware with distributed-system architectures are discussed. The HSIS is intended for 100-Mb/s operation of a local-area network with up to 256 stations. It comprises a bus transmission system (passive star couplers and linear media linked by active elements) and network interface units (NIUs). Each NIU is designed to perform the physical, data link, network, and transport functions defined by the ISO OSI Basic Reference Model (1982 and 1983) and incorporates a fiber-optic transceiver, a high-speed protocol based on the SAE AE-9B linear token-passing data bus (1986), and a specialized application interface unit. The operating modes and capabilities of HSIS are described in detail and illustrated with diagrams.

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

Directory of Open Access Journals (Sweden)

Mota Carmen

2017-04-01

Full Text Available 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

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

Science.gov (United States)

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

Turbulent transport in the atmospheric surface layer

Energy Technology Data Exchange (ETDEWEB)

Tagesson, Torbern [Dept. of Physical Geography and Ecosystem Science, Lund Univ., Lund (Sweden)

2012-04-15

In the modelling of transport and accumulation of the radioactive isotope carbon-14 (C-14) in the case of a potential release from a future repository of radioactive waste, it is important to describe the transport of the isotope in the atmosphere. This report aims to describe the turbulent transport within the lower part of the atmosphere; the inertial surface layer and the roughness sublayer. Transport in the inertial surface layer is dependent on several factors, whereof some can be neglected under certain circumstances. Under steady state conditions, fully developed turbulent conditions, in flat and horizontal homogeneous areas, it is possible to apply an eddy diffusivity approach for estimating vertical transport of C. The eddy diffusivity model assumes that there is proportionality between the vertical gradient and the transport of C. The eddy diffusivity is depending on the atmospheric turbulence, which is affected by the interaction between mean wind and friction of the ground surface and of the sensible heat flux in the atmosphere. In this report, it is described how eddy diffusivity of the inertial surface layer can be estimated from 3-d wind measurements and measurements of sensible heat fluxes. It is also described how to estimate the eddy diffusivity in the inertial surface layer from profile measurements of temperature and wind speed. Close to the canopy, wind and C profiles are influenced by effects of the surface roughness; this section of the atmosphere is called the roughness sublayer. Its height is up to {approx}3 times the height of the plant canopy. When the mean wind interacts with the canopy, turbulence is not only produced by shear stress and buoyancy, it is additionally created by wakes, which are formed behind the plants. Turbulence is higher than it would be over a flat surface, and the turbulent transport is hereby more efficient. Above the plant canopy, but still within the roughness sublayer, a function that compensates for the effect

Turbulent transport in the atmospheric surface layer

International Nuclear Information System (INIS)

Tagesson, Torbern

2012-04-01

In the modelling of transport and accumulation of the radioactive isotope carbon-14 (C-14) in the case of a potential release from a future repository of radioactive waste, it is important to describe the transport of the isotope in the atmosphere. This report aims to describe the turbulent transport within the lower part of the atmosphere; the inertial surface layer and the roughness sublayer. Transport in the inertial surface layer is dependent on several factors, whereof some can be neglected under certain circumstances. Under steady state conditions, fully developed turbulent conditions, in flat and horizontal homogeneous areas, it is possible to apply an eddy diffusivity approach for estimating vertical transport of C. The eddy diffusivity model assumes that there is proportionality between the vertical gradient and the transport of C. The eddy diffusivity is depending on the atmospheric turbulence, which is affected by the interaction between mean wind and friction of the ground surface and of the sensible heat flux in the atmosphere. In this report, it is described how eddy diffusivity of the inertial surface layer can be estimated from 3-d wind measurements and measurements of sensible heat fluxes. It is also described how to estimate the eddy diffusivity in the inertial surface layer from profile measurements of temperature and wind speed. Close to the canopy, wind and C profiles are influenced by effects of the surface roughness; this section of the atmosphere is called the roughness sublayer. Its height is up to ∼3 times the height of the plant canopy. When the mean wind interacts with the canopy, turbulence is not only produced by shear stress and buoyancy, it is additionally created by wakes, which are formed behind the plants. Turbulence is higher than it would be over a flat surface, and the turbulent transport is hereby more efficient. Above the plant canopy, but still within the roughness sublayer, a function that compensates for the effect of

Study of cutting speed on surface roughness and chip formation when machining nickel-based alloy

International Nuclear Information System (INIS)

Khidhir, Basim A.; Mohamed, Bashir

2010-01-01

Nickel- based alloy is difficult-to-machine because of its low thermal diffusive property and high strength at higher temperature. The machinability of nickel- based Hastelloy C-276 in turning operations has been carried out using different types of inserts under dry conditions on a computer numerical control (CNC) turning machine at different stages of cutting speed. The effects of cutting speed on surface roughness have been investigated. This study explores the types of wear caused by the effect of cutting speed on coated and uncoated carbide inserts. In addition, the effect of burr formation is investigated. The chip burr is found to have different shapes at lower speeds. Triangles and squares have been noticed for both coated and uncoated tips as well. The conclusion from this study is that the transition from thick continuous chip to wider discontinuous chip is caused by different types of inserts. The chip burr has a significant effect on tool damage starting in the line of depth-of-cut. For the coated insert tips, the burr disappears when the speed increases to above 150 m/min with the improvement of surface roughness; increasing the speed above the same limit for uncoated insert tips increases the chip burr size. The results of this study showed that the surface finish of nickel-based alloy is highly affected by the insert type with respect to cutting speed changes and its effect on chip burr formation and tool failure

A DOUBLE-RING ALGORITHM FOR MODELING SOLAR ACTIVE REGIONS: UNIFYING KINEMATIC DYNAMO MODELS AND SURFACE FLUX-TRANSPORT SIMULATIONS

International Nuclear Information System (INIS)

Munoz-Jaramillo, Andres; Martens, Petrus C. H.; Nandy, Dibyendu; Yeates, Anthony R.

2010-01-01

The emergence of tilted bipolar active regions (ARs) and the dispersal of their flux, mediated via processes such as diffusion, differential rotation, and meridional circulation, is believed to be responsible for the reversal of the Sun's polar field. This process (commonly known as the Babcock-Leighton mechanism) is usually modeled as a near-surface, spatially distributed α-effect in kinematic mean-field dynamo models. However, this formulation leads to a relationship between polar field strength and meridional flow speed which is opposite to that suggested by physical insight and predicted by surface flux-transport simulations. With this in mind, we present an improved double-ring algorithm for modeling the Babcock-Leighton mechanism based on AR eruption, within the framework of an axisymmetric dynamo model. Using surface flux-transport simulations, we first show that an axisymmetric formulation-which is usually invoked in kinematic dynamo models-can reasonably approximate the surface flux dynamics. Finally, we demonstrate that our treatment of the Babcock-Leighton mechanism through double-ring eruption leads to an inverse relationship between polar field strength and meridional flow speed as expected, reconciling the discrepancy between surface flux-transport simulations and kinematic dynamo models.

IMPROVED METHOD OF DETERMINATION OF ECONOMIC EFFICIENCY OF CONSTRUCTION AND OPERATION OF HIGH SPEED MAINLINE IN UKRAINE

Directory of Open Access Journals (Sweden)

YU. S. Barash

2014-01-01

Full Text Available Purpose. To develop an advanced methodology and formulate the measures concerning the definition of economic efficiency of high-speed movement organization taking into account the operating experience of rapid transportations in Ukraine, travel time, number of stops on the route, schedule and the demand for these transportations. Methodology. The economic feasibility for appropriateness of high-speed movement organization in Ukraine is an investment project, which involves step-by-step money investment to the construction. To solve such problems one uses net present value, which UZ or newly created companies can get during the project realization and after its completion. Findings. On the basis of obtained studies one can state that the methodology of complex determination of construction efficiency and high-speed passenger trains operation taking into account the cost of infrastructure, rolling stock, impact of environmental factors, etc. was developed in the article. Originality. We propose a scientific approach to determine the economic efficiency of the construction and high-speed main lines operation. This approach, unlike the existing one, includes the improved principles of determining the passenger traffic, the cost of high-speed mainline construction, the number of rolling stock; optimizes income and expenditure calculations in the context of competitive advantages and impact of the external factors on the company. For the first time it was taken into account the transit flow of passengers departing from CIS countries to the vacation in the Crimea, the Carpathians, Odessa and Lviv regions. The account of these factors increases the feasibility of administrative decisions concerning ensuring the efficiency of high-speed traffic functioning. Practical value. The proposed methodology and the research results allowed determining the construction reasonability of high-speed mainline for the passenger trains with a speed at least250 km/h in

Multivariable Techniques for High-Speed Research Flight Control Systems

Science.gov (United States)

Newman, Brett A.

1999-01-01

This report describes the activities and findings conducted under contract with NASA Langley Research Center. Subject matter is the investigation of suitable multivariable flight control design methodologies and solutions for large, flexible high-speed vehicles. Specifically, methodologies are to address the inner control loops used for stabilization and augmentation of a highly coupled airframe system possibly involving rigid-body motion, structural vibrations, unsteady aerodynamics, and actuator dynamics. Design and analysis techniques considered in this body of work are both conventional-based and contemporary-based, and the vehicle of interest is the High-Speed Civil Transport (HSCT). Major findings include: (1) control architectures based on aft tail only are not well suited for highly flexible, high-speed vehicles, (2) theoretical underpinnings of the Wykes structural mode control logic is based on several assumptions concerning vehicle dynamic characteristics, and if not satisfied, the control logic can break down leading to mode destabilization, (3) two-loop control architectures that utilize small forward vanes with the aft tail provide highly attractive and feasible solutions to the longitudinal axis control challenges, and (4) closed-loop simulation sizing analyses indicate the baseline vane model utilized in this report is most likely oversized for normal loading conditions.

Computational Model for Impact-Resisting Critical Thickness of High-Speed Machine Outer Protective Plate

Science.gov (United States)

Wu, Huaying; Wang, Li Zhong; Wang, Yantao; Yuan, Xiaolei

2018-05-01

The blade or surface grinding blade of the hypervelocity grinding wheel may be damaged due to too high rotation rate of the spindle of the machine and then fly out. Its speed as a projectile may severely endanger the field persons. Critical thickness model of the protective plate of the high-speed machine is studied in this paper. For easy analysis, the shapes of the possible impact objects flying from the high-speed machine are simplified as sharp-nose model, ball-nose model and flat-nose model. Whose front ending shape to represent point, line and surface contacting. Impact analysis based on J-C model is performed for the low-carbon steel plate with different thicknesses in this paper. One critical thickness computational model for the protective plate of high-speed machine is established according to the damage characteristics of the thin plate to get relation among plate thickness and mass, shape and size and impact speed of impact object. The air cannon is used for impact test. The model accuracy is validated. This model can guide identification of the thickness of single-layer outer protective plate of a high-speed machine.

City transport of the future - the high speed pedestrian conveyor. Part 2: ergonomic considerations of complete conveyor systems.

Science.gov (United States)

Browning, A C

1975-03-01

This is the second part of an article on an unusual form of passenger transport, the moving pavement or pedestrian conveyor running at speeds up to 16 km/h. Part 1, "Ergonomic considerations of acceleration, deceleration and transfer sections," was published in the December, 1974, issue.

Perspectives in high-speed transport: Maglev and/or wheel-and-rail techniques

Energy Technology Data Exchange (ETDEWEB)

Hochbruck, H

1985-03-01

Proceeding from a consideration of possible system structures, a technically and economically meaning-full top speed for a railway system is developed which offers, in competition with the airplane and the private car, good chances of winning an appropriate share of the traffic where the distances are in the range of about 400 to 600 km. It is deduced from the present state of developments in high-speed wheel/rail systems and in maglev technology that the wheel/rail mode has clear advantages where a network is concerned. Maglev technology is now being brought to the stage of operational readiness and its first applications are likely to be for point-to-point or direct-line links.

High resolution, high speed ultrahigh vacuum microscopy

International Nuclear Information System (INIS)

Poppa, Helmut

2004-01-01

The history and future of transmission electron microscopy (TEM) is discussed as it refers to the eventual development of instruments and techniques applicable to the real time in situ investigation of surface processes with high resolution. To reach this objective, it was necessary to transform conventional high resolution instruments so that an ultrahigh vacuum (UHV) environment at the sample site was created, that access to the sample by various in situ sample modification procedures was provided, and that in situ sample exchanges with other integrated surface analytical systems became possible. Furthermore, high resolution image acquisition systems had to be developed to take advantage of the high speed imaging capabilities of projection imaging microscopes. These changes to conventional electron microscopy and its uses were slowly realized in a few international laboratories over a period of almost 40 years by a relatively small number of researchers crucially interested in advancing the state of the art of electron microscopy and its applications to diverse areas of interest; often concentrating on the nucleation, growth, and properties of thin films on well defined material surfaces. A part of this review is dedicated to the recognition of the major contributions to surface and thin film science by these pioneers. Finally, some of the important current developments in aberration corrected electron optics and eventual adaptations to in situ UHV microscopy are discussed. As a result of all the path breaking developments that have led to today's highly sophisticated UHV-TEM systems, integrated fundamental studies are now possible that combine many traditional surface science approaches. Combined investigations to date have involved in situ and ex situ surface microscopies such as scanning tunneling microscopy/atomic force microscopy, scanning Auger microscopy, and photoemission electron microscopy, and area-integrating techniques such as x-ray photoelectron

Ion source techniques for high-speed processing of material surface by ion beams

International Nuclear Information System (INIS)

Ishikawa, Junzo

1990-01-01

The present paper discusses some key or candidate techniques for future ion source development and such ion sources developed by the author. Several types of microwave ion sources for producing low charge state ions have been developed in Japan. When a microwave plasma cathode developed by the author is adapted to a Kaufman type ion source, the electron emission currents are found to be 2.5 A for argon gas and 0.5-0.9 A for oxygen gas. An alternative ionization method for metal atoms is strongly required for high-speed processing of material surface by metal-ion beams. Detailed discussion is made of collisional ionization of vaporized atoms, and negative-ion production (secondary negative-ion emission by sputtering). An impregnated electrode type liquid-metal ion source developed by the author, which has a porous tip structure, is described. The negative-ion production efficiency is quite high. The report also presents a neutral and ionized alkaline-metal bombardment type heavy negative-ion source, which consists of a cesium plasma ion source, suppressor, target electrode, negative-ion extraction electrode, and einzel lens. (N.K.)

High-speed collision of copper nanoparticle with aluminum surface: Molecular dynamics simulation

Science.gov (United States)

Pogorelko, Victor V.; Mayer, Alexander E.; Krasnikov, Vasiliy S.

2016-12-01

We investigate the effect of the high-speed collision of copper nanoparticles with aluminum surface by means of molecular dynamic simulations. Studied diameter of nanoparticles is varied within the range 7.2-22 nm and the velocity of impact is equal to 500 or 1000 m/s. Dislocation analysis shows that a large quantity of dislocations is formed within the impact area. Overall length of dislocations is determined, first of all, by the impact velocity and by the size of incident copper nanoparticle, in other words, by the kinetic energy of the nanoparticle. Dislocations occupy the total volume of the impacted aluminum single crystal layer (40.5 nm in thickness) in the form of intertwined structure in the case of large kinetic energy of the incident nanoparticle. Decrease in the initial kinetic energy or increase in the layer thickness lead to restriction of the penetration depth of the dislocation net; formation of separate dislocation loops is observed in this case. Increase in the initial system temperature slightly raises the dislocation density inside the bombarded layer and considerably decreases the dislocation density inside the nanoparticle. The temperature increase also leads to a deeper penetration of the copper atoms inside the aluminum. Additional molecular dynamic simulations show that the deposited particles demonstrate a very good adhesion even in the case of the considered relatively large nanoparticles. Medium energy of the nanoparticles corresponding to velocity of about 500 m/s and elevated temperature of the system about 700-900 K are optimal parameters for production of high-quality layers of copper on the aluminum surface. These conditions provide both a good adhesion and a less degree of the plastic deformation. At the same time, higher impact velocities can be used for combined treatment consisting of both the plastic deformation and the coating.

Development of nanomanipulator using a high-speed atomic force microscope coupled with a haptic device

International Nuclear Information System (INIS)

Iwata, F.; Ohashi, Y.; Ishisaki, I.; Picco, L.M.; Ushiki, T.

2013-01-01

The atomic force microscope (AFM) has been widely used for surface fabrication and manipulation. However, nanomanipulation using a conventional AFM is inefficient because of the sequential nature of the scan-manipulation scan cycle, which makes it difficult for the operator to observe the region of interest and perform the manipulation simultaneously. In this paper, a nanomanipulation technique using a high-speed atomic force microscope (HS-AFM) is described. During manipulation using the AFM probe, the operation is periodically interrupted for a fraction of a second for high-speed imaging that allows the topographical image of the manipulated surface to be periodically updated. With the use of high-speed imaging, the interrupting time for imaging can be greatly reduced, and as a result, the operator almost does not notice the blink time of the interruption for imaging during the manipulation. This creates a more intuitive interface with greater feedback and finesse to the operator. Nanofabrication under real-time monitoring was performed to demonstrate the utility of this arrangement for real-time nanomanipulation of sample surfaces under ambient conditions. Furthermore, the HS-AFM is coupled with a haptic device for the human interface, enabling the operator to move the HS-AFM probe to any position on the surface while feeling the response from the surface during the manipulation. - Highlights: • A nanomanipulater based on a high-speed atomic force microscope was developped. • High-speed imaging provides a valuable feedback during the manipulation operation. • Operator can feel the response from the surface via a haptic device during manipulation. • Nanofabrications under real-time monitoring were successfully performed

The effect of surface pressure modification on the speed of vortex rings

Energy Technology Data Exchange (ETDEWEB)

Partridge, Matthew; Davis, Frank; Higson, Seamus P J [Centre of Biomedical Imaging, Cranfield University, Cranfield MK43 0AL (United Kingdom); James, Stephen W; Tatam, Ralph P, E-mail: f.davis@cranfield.ac.uk [Engineering Photonics, School of Engineering, Cranfield University, Cranfield MK43 0AL (United Kingdom)

2014-10-01

A series of experiments investigating the relationship between surface pressure, monolayer elasticity and the speed of vortex rings is presented. A drop of water, when touched to the surface of a larger body of water, will coalesce and form a vortex ring that moves perpendicularly to the surface of the water. The speed of the vortex ring movement away from the surface of the water has been seen to be sensitive to the presence of monolayer materials. Here we explore the influence of four monolayer forming materials, stearic acid, tricosanoic acid, 4-tert butyl calix[4]arene and calix[4]resorcarene (C11), on the properties of vortex rings. For each material, the speed of the vortex rings through the water was measured at a range of surface pressures. The speed was found to increase in a linear fashion until surface pressures greater than 30 mN m{sup −1}, where the ring’s speed decreased towards the value measured in the absence of a monolayer. Analysis of the results suggests a future route toward a better understanding of the mechanisms involved.

High-speed research program systems analysis activities at Ames Research Center

Science.gov (United States)

Kidwell, George H.

1992-01-01

The Ames Systems Analysis Branch has been working to support the High Speed Research Program (HSRP) for nearly one year. Both the status of methodology development activities and the results of studies are presented whether completed or underway. The discussion involves the conceptual design synthesis program used for High Speed Civil Transport (HSCT) studies, ACSYNT (aircraft synthesis), and enhancements that have been made especially for HSRP. Some results are presented for one study that has been completed and two that are underway. These are the advanced controls integration study, the fuel cost impact study, and the oblique wing configuration evaluation that is part of a larger innovative concepts study.

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

Science.gov (United States)

2010-07-01

..., monorails and systems. 1192.175 Section 1192.175 Parks, Forests, and Public Property ARCHITECTURAL AND... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.175 High-speed rail cars, monorails and systems. (a... steel-wheel-on-steel-rail technology, and monorail systems operating primarily on dedicated rail (i.e...

Mapping near-surface air temperature, pressure, relative humidity and wind speed over Mainland China with high spatiotemporal resolution

Science.gov (United States)

Li, Tao; Zheng, Xiaogu; Dai, Yongjiu; Yang, Chi; Chen, Zhuoqi; Zhang, Shupeng; Wu, Guocan; Wang, Zhonglei; Huang, Chengcheng; Shen, Yan; Liao, Rongwei

2014-09-01

As part of a joint effort to construct an atmospheric forcing dataset for mainland China with high spatiotemporal resolution, a new approach is proposed to construct gridded near-surface temperature, relative humidity, wind speed and surface pressure with a resolution of 1 km×1 km. The approach comprises two steps: (1) fit a partial thin-plate smoothing spline with orography and reanalysis data as explanatory variables to ground-based observations for estimating a trend surface; (2) apply a simple kriging procedure to the residual for trend surface correction. The proposed approach is applied to observations collected at approximately 700 stations over mainland China. The generated forcing fields are compared with the corresponding components of the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis dataset and the Princeton meteorological forcing dataset. The comparison shows that, both within the station network and within the resolutions of the two gridded datasets, the interpolation errors of the proposed approach are markedly smaller than the two gridded datasets.

To Enhance the Fire Resistance Performance of High-Speed Steel Roller Door with Water Film System

Directory of Open Access Journals (Sweden)

De-Hua Chung

2015-01-01

Full Text Available The structure of high-speed roller door with water film has improved in this study. The flameproof water film system is equipped with a water circulating device to reduce the water consumption of water film system. The water film is generated at the roller box of the high-speed roller door in this study. The heating test is done with the full-scale heating furnace. Both cases of the water film on unexposed surface and water film on exposed surface passed the fire resistance test based on ISO 834, proving that the high-speed roller door with water film system has 120A fire resistance period. The main findings indicate that the water film on exposed surface shows that as the amount of water film evaporated by high temperature inside the furnace must be greater than the evaporation capacity of water film on unexposed surface, the required water supply is 660 L more than the water film on unexposed surface.

Plasmonic color metasurfaces fabricated by a high speed roll-to-roll method

DEFF Research Database (Denmark)

Murthy, Swathi; Pranov, Henrik; Feidenhans'l, Nikolaj Agentoft

2017-01-01

Lab-scale plasmonic color printing using nano-structured and subsequently metallized surfaces have been demonstrated to provide vivid colors. However, upscaling these structures for large area manufacturing is extremely challenging due to the requirement of nanometer precision of metal thickness....... In this study, we have investigated a plasmonic color meta-surface design that can be easily upscaled. We have demonstrated the feasibility of fabrication of these plasmonic color surfaces by a high-speed roll-to-roll method, comprising roll-to-roll extrusion coating at 10 m min-1 creating a polymer foil having...... 100 nm deep pits of varying sub-wavelength diameter and pitch length. Subsequently this polymer foil was metallized and coated also by high-speed roll-to-roll methods. The perceived colors have high tolerance towards the thickness of the metal layer, when this thickness exceeds the depths of the pits...

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

Science.gov (United States)

Park, Sunyoung; Ishii, Miaki

2018-06-01

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

High-speed infrared thermography for the measurement of microscopic boiling parameters on micro- and nano-structured surfaces

International Nuclear Information System (INIS)

Park, Youngjae; Kim, Hyungdae; Kim, Hyungmo; Kim, Joonwon

2014-01-01

Micro- and nano-scale structures on boiling surfaces can enhance nucleate boiling heat transfer coefficient (HTC) and critical heat flux (CHF). A few studies were conducted to explain the enhancements of HTC and CHF using the microscopic boiling parameters. Quantitative measurements of microscopic boiling parameters are needed to understand the physical mechanism of the boiling heat transfer augmentation on structured surfaces. However, there is no existing experimental techniques to conveniently measure the boiling parameters on the structured surfaces because of the small (high-speed infrared (IR) thermography to visualize liquid-vapor phase distribution during nucleate pool boiling on micro- and nano-structured surfaces. The visualization results are analyzed to obtain the microscopic boiling parameters. Finally, quantitative microscopic boiling parameters are used to interpret the enhancement of HTC and CHF. In this study, liquid-vapor phase distributions of each surface were clearly visualized by IR thermography during the nucleate boiling phenomena. From the visualization results, following microscopic boiling parameters were quantitatively measured by image processing. - Number density of dry patch, NDP IR thermography technique was demonstrated by nucleate pool boiling experiments with M- and N surfaces. The enhancement of HTC and CHF could be explained by microscopic boiling parameters

Surface transport in plasma-balls

Energy Technology Data Exchange (ETDEWEB)

Armas, Jay [Physique Théorique et Mathématique, Université Libre de Bruxelles andInternational Solvay Institutes,ULB-Campus Plaine CP231, B-1050 Brussels (Belgium); Bhattacharya, Jyotirmoy [Centre for Particle Theory & Department of Mathematical Sciences, Durham University,South Road, Durham DH1 3LE (United Kingdom); Kundu, Nilay [Harish-Chandra Research Institute,Chhatnag Road, Jhunsi, Allahabad 211019 (India)

2016-06-06

We study the surface transport properties of stationary localized configurations of relativistic fluids to the first two non-trivial orders in a derivative expansion. By demanding that these finite lumps of relativistic fluid are described by a thermal partition function with arbitrary stationary background metric and gauge fields, we are able to find several constraints among surface transport coefficients. At leading order, besides recovering the surface thermodynamics, we obtain a generalization of the Young-Laplace equation for relativistic fluid surfaces, by considering a temperature dependence in the surface tension, which is further generalized in the context of superfluids. At the next order, for uncharged fluids in 3+1 dimensions, we show that besides the 3 independent bulk transport coefficients previously known, a generic localized configuration is characterized by 3 additional surface transport coefficients, one of which may be identified with the surface modulus of rigidity. Finally, as an application, we study the effect of temperature dependence of surface tension on some explicit examples of localized fluid configurations, which are dual to certain non-trivial black hole solutions via the AdS/CFT correspondence.

METHOD OF CONVERSION OF HIGH- AND MIDDLE-SPEED DIESEL ENGINES INTO GAS DIESEL ENGINES

Directory of Open Access Journals (Sweden)

Mikhail G. Shatrov

2017-12-01

Full Text Available The paper aims at the development of fuel supply and electronic control systems for boosted high- and middle-speed transport engines. A detailed analysis of different ways of converting diesel engine to operate on natural gas was carried out. The gas diesel process with minimized ignition portion of diesel fuel injected by the Common Rail (CR system was selected. Electronic engine control and modular gas feed systems which can be used both on high- and middle-speed gas diesel engines were developed. Also diesel CR fuel supply systems were developed in cooperation with the industrial partner, namely, those that can be mounted on middle-speed diesel and gas diesel engines. Electronic control and gas feed systems were perfected using modeling and engine tests. The high-speed diesel engine was converted into a gas diesel one. After perfection of the gas feed and electronic control systems, bench tests of the high-speed gas diesel engine were carried out showing a high share of diesel fuel substitution with gas, high fuel efficiency and significant decrease of NOх and СО2 emissions.

Cavitation performance improvement of high specific speed mixed-flow pump

International Nuclear Information System (INIS)

Chen, T; Sun, Y B; Wu, D Z; Wang, L Q

2012-01-01

Cavitation performance improvement of large hydraulic machinery such as pump and turbine has been a hot topic for decades. During the design process of the pumps, in order to minimize size, weight and cost centrifugal and mixed-flow pump impellers are required to operate at the highest possible rotational speed. The rotational speed is limited by the phenomenon of cavitation. The hydraulic model of high-speed mixed-flow pump with large flow rate and high pumping head, which was designed based on the traditional method, always involves poor cavitation performance. In this paper, on the basis of the same hydraulic design parameters, two hydraulic models of high-speed mixed-flow pump were designed by using different methods, in order to investigate the cavitation and hydraulic performance of the two models, the method of computational fluid dynamics (CFD) was adopted for internal flow simulation of the high specific speed mixed-flow pump. Based on the results of numerical simulation, the influences of impeller parameters and three-dimensional configuration on pressure distribution of the blades' suction surfaces were analyzed. The numerical simulation results shows a better pressure distribution and lower pressure drop around the leading edge of the improved model. The research results could provide references to the design and optimization of the anti-cavitation blade.

High-speed AC motors

Energy Technology Data Exchange (ETDEWEB)

Jokinen, T.; Arkkio, A. [Helsinki University of Technology Laboratory of Electromechanics, Otaniemi (Finland)

1997-12-31

The paper deals with various types of highspeed electric motors, and their limiting powers. Standard machines with laminated rotors can be utilised if the speed is moderate. The solid rotor construction makes it possible to reach higher power and speed levels than those of laminated rotors. The development work on high-speed motors done at Helsinki University of Technology is presented, too. (orig.) 12 refs.

Modeling wind adjustment factor and midflame wind speed for Rothermel's surface fire spread model

Science.gov (United States)

Patricia L. Andrews

2012-01-01

Rothermel's surface fire spread model was developed to use a value for the wind speed that affects surface fire, called midflame wind speed. Models have been developed to adjust 20-ft wind speed to midflame wind speed for sheltered and unsheltered surface fuel. In this report, Wind Adjustment Factor (WAF) model equations are given, and the BehavePlus fire modeling...

Subsidence Evaluation of High-Speed Railway in Shenyang Based on Time-Series Insar

Science.gov (United States)

Zhang, Yun; Wei, Lianhuan; Li, Jiayu; Liu, Shanjun; Mao, Yachun; Wu, Lixin

2018-04-01

More and more high-speed railway are under construction in China. The slow settlement along high-speed railway tracks and newly-built stations would lead to inhomogeneous deformation of local area, and the accumulation may be a threat to the safe operation of high-speed rail system. In this paper, surface deformation of the newly-built high-speed railway station as well as the railway lines in Shenyang region will be retrieved by time series InSAR analysis using multi-orbit COSMO-SkyMed images. This paper focuses on the non-uniform subsidence caused by the changing of local environment along the railway. The accuracy of the settlement results can be verified by cross validation of the results obtained from two different orbits during the same period.

Homogenization of Tianjin monthly near-surface wind speed using RHtestsV4 for 1951-2014

Science.gov (United States)

Si, Peng; Luo, Chuanjun; Liang, Dongpo

2018-05-01

Historical Chinese surface meteorological records provided by the special fund for basic meteorological data from the National Meteorological Information Center (NMIC) were processed to produce accurate wind speed data. Monthly 2-min near-surface wind speeds from 13 observation stations in Tianjin covering 1951-2014 were homogenized using RHtestV4 combined with their metadata. Results indicate that 10 stations had significant breakpoints—77% of the Tianjin stations—suggesting that inhomogeneity was common in the Tianjin wind speed series. Instrument change accounted for most changes, based on the metadata, including changes in type and height, especially for the instrument type. Average positive quantile matching (QM) adjustments were more than negative adjustments at 10 stations; positive biases with a probability density of 0.2 or more were mainly concentrates in the range 0.2 m s-1 to 1.2 m s-1, while the corresponding negative biases were mainly in the range -0.1 to -1.2 m s-1. Here, changes in variances and trends in the monthly mean surface wind speed series at 10 stations before and after adjustment were compared. Climate characteristics of wind speed in Tianjin were more reasonably reflected by the adjusted data; inhomogeneity in wind speed series was largely corrected. Moreover, error analysis reveals that there was a high consistency between the two datasets here and that from the NMIC, with the latter as the reference. The adjusted monthly near-surface wind speed series shows a certain reliability for the period 1951-2014 in Tianjin.

Research on the impact of surface properties of particle on damping effect in gear transmission under high speed and heavy load

Science.gov (United States)

Xiao, Wangqiang; Chen, Zhiwei; Pan, Tianlong; Li, Jiani

2018-01-01

The vibration and noise from gear transmission have great damage on the mechanical equipment and operators. Through inelastic collisions and friction between particles, the energy can be dissipated in gear transmission. A dynamic model of particle dampers in gear transmission was put forward in this paper. The performance of particle dampers in centrifugal fields under different rotational speeds and load was investigated. The surface properties such as the impact of coefficient of restitution and friction coefficient of the particle on the damping effect were analyzed and the total energy loss was obtained by discrete element method (DEM). The vibration from time-varying mesh stiffness was effectively reduced by particle dampers and the optimum coefficient of restitution was discovered under different rotational speeds and load. Then, a test bench for gear transmission was constructed, and the vibration of driven gear and driving gear were measured through a three-directional wireless acceleration sensor. The research results agree well with the simulation results. While at relatively high speed, smaller coefficient of restitution achieves better damping effect. As to friction coefficient, at relatively high speed, the energy dissipation climbs up and then declines with the increase of the friction coefficient. The results can provide guidelines for the application of particle damper in gear transmission.

Photonic Technologies for Ultra-High-Speed Information Highways

DEFF Research Database (Denmark)

Bouchoule, S; Lèfevre, R.; Legros, E.

1999-01-01

The ACTS project HIGHWAY (AC067) addresses promising ultra-high speed optoelectronic components and system technologies for 40 Gbit/s time-division-multiplexed (TDM) transport systems. Advanced 40 Gbit/s TDM system lab demonstrators are to be realized and tested over installed field fiber testbeds....... This paper reviews the current status of 40 Gbit/s TDM components and subsystem technologies achieved in HIGHWAY. The results of HIGHWAY 40 Gbit/s TDM systems and field tests will be reported in a subsequent paper. (C) 1999 Academic Press....

High speed operation of permanent magnet machines

Science.gov (United States)

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

Using GPS-derived speed patterns for recognition of transport modes in adults

NARCIS (Netherlands)

Huss, Anke|info:eu-repo/dai/nl/331385880; Beekhuizen, Johan|info:eu-repo/dai/nl/34472641X; Kromhout, Hans|info:eu-repo/dai/nl/074385224; Vermeulen, Roel|info:eu-repo/dai/nl/216532620

2014-01-01

BACKGROUND: Identification of active or sedentary modes of transport is of relevance for studies assessing physical activity or addressing exposure assessment. We assessed in a proof-of-principle study if speed as logged by GPSs could be used to identify modes of transport (walking, bicycling, and

Aircraft Emission Scenarios Projected in Year 2015 for the NASA Technology Concept Aircraft (TCA) High Speed Civil Transport

Science.gov (United States)

Baughcum, Steven L.; Henderson, Stephen C.

1998-01-01

This report describes the development of a three-dimensional database of aircraft fuel burn and emissions (fuel burned, NOx, CO, and hydrocarbons) from projected fleets of high speed civil transports (HSCTs) on a universal airline network. Inventories for 500 and 1000 HSCT fleets, as well as the concurrent subsonic fleets, were calculated. The HSCT scenarios are calculated using the NASA technology concept airplane (TCA) and update an earlier report. These emissions inventories are available for use by atmospheric scientists conducting the Atmospheric Effects of Stratospheric Aircraft (AESA) modeling studies. Fuel burned and emissions of nitrogen oxides (NOx as NO2), carbon monoxide, and hydrocarbons have been calculated on a 1 degree latitude x 1 degree longitude x 1 kilometer pressure altitude grid and delivered to NASA as electronic files.

Softwood sawlog secondary transport travel speed prediction for the ...

African Journals Online (AJOL)

The objective of this study was to develop a predictive model for travel speed of softwood sawlog timber transport (STT) vehicles over a range of forest and provincial roads of varying condition for the South African forestry industry. Data was accumulated from both the Eastern Cape/KwaZulu-Natal and Mpumalanga forest ...

High-Speed Rail for Central and Eastern European Countries: A Conference Report

Directory of Open Access Journals (Sweden)

Jandová Monika

2016-09-01

Full Text Available The European transport strategy promotes the role of railways and expects that the key role in passenger transport should be played by high-speed rail (HSR. Although the core network of high-speed lines has already been built and is operating in Western Europe, there has been little coverage so far in Central and Eastern Europe (CEE. The aim of the conference “High-Speed Rail for CEE Countries” that took place in Prague in June 2016 was to put together academics, policy-makers, and practitioners interested in HSR and to formulate recommendations for CEE countries based on West European countries’ experience. Based on the conference presentations and subsequent discussion, the following conclusions were formulated. Firstly, there are many crucial differences in national HSR build-up and operation, which means that former experience of Western Europe is not directly applicable to CEE countries. Secondly, in comparing presentations discussing experiences in France, Britain, Italy, and Germany, it was concluded that the German approach-upgrading existing lines where possible and only building new lines for bottleneck sections-was the most likely appropriate solution in CEE. Lastly, CEE has the additional problem of many border crossings, with a reduction of traffic in comparison with purely domestic routes, and this effect has to be taken into account.

Increased Surface Wind Speeds Follow Diminishing Arctic Sea Ice

Science.gov (United States)

Mioduszewski, J.; Vavrus, S. J.; Wang, M.; Holland, M. M.; Landrum, L.

2017-12-01

Projections of Arctic sea ice through the end of the 21st century indicate the likelihood of a strong reduction in ice area and thickness in all seasons, leading to a substantial thermodynamic influence on the overlying atmosphere. This is likely to have an effect on winds over the Arctic Basin, due to changes in atmospheric stability and/or baroclinicity. Prior research on future Arctic wind changes is limited and has focused mainly on the practical impacts on wave heights in certain seasons. Here we attempt to identify patterns and likely mechanisms responsible for surface wind changes in all seasons across the Arctic, particularly those associated with sea ice loss in the marginal ice zone. Sea level pressure, near-surface (10 m) and upper-air (850 hPa) wind speeds, and lower-level dynamic and thermodynamic variables from the Community Earth System Model Large Ensemble Project (CESM-LE) were analyzed for the periods 1971-2000 and 2071-2100 to facilitate comparison between a present-day and future climate. Mean near-surface wind speeds over the Arctic Ocean are projected to increase by late century in all seasons but especially during autumn and winter, when they strengthen by up to 50% locally. The most extreme wind speeds in the 90th percentile change even more, increasing in frequency by over 100%. The strengthened winds are closely linked to decreasing lower-tropospheric stability resulting from the loss of sea ice cover and consequent surface warming (locally over 20 ºC warmer in autumn and winter). A muted pattern of these future changes is simulated in CESM-LE historical runs from 1920-2005. The enhanced winds near the surface are mostly collocated with weaker winds above the boundary layer during autumn and winter, implying more vigorous vertical mixing and a drawdown of high-momentum air.The implications of stronger future winds include increased coastal hazards and the potential for a positive feedback with sea ice by generating higher winds and

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

International Nuclear Information System (INIS)

Chester, Mikhail; Horvath, Arpad

2012-01-01

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. (letter)

Surface drag effects on simulated wind fields in high-resolution atmospheric forecast model

Energy Technology Data Exchange (ETDEWEB)

Lim, Kyo Sun; Lim, Jong Myoung; Ji, Young Yong [Environmental Radioactivity Assessment Team,Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Shin, Hye Yum [NOAA/Geophysical Fluid Dynamics Laboratory, Princeton (United States); Hong, Jin Kyu [Yonsei University, Seoul (Korea, Republic of)

2017-04-15

It has been reported that the Weather Research and Forecasting (WRF) model generally shows a substantial over prediction bias at low to moderate wind speeds and winds are too geostrophic (Cheng and Steenburgh 2005), which limits the application of WRF model in the area that requires the accurate surface wind estimation such as wind-energy application, air-quality studies, and radioactive-pollutants dispersion studies. The surface drag generated by the subgrid-scale orography is represented by introducing a sink term in the momentum equation in their studies. The purpose of our study is to evaluate the simulated meteorological fields in the high-resolution WRF framework, that includes the parameterization of subgrid-scale orography developed by Mass and Ovens (2010), and enhance the forecast skill of low-level wind fields, which plays an important role in transport and dispersion of air pollutants including radioactive pollutants. The positive bias in 10-m wind speed is significantly alleviated by implementing the subgrid-scale orography parameterization, while other meteorological fields including 10-m wind direction are not changed. Increased variance of subgrid- scale orography enhances the sink of momentum and further reduces the bias in 10-m wind speed.

Technology of high-speed combined machining with brush electrode

Science.gov (United States)

Kirillov, O. N.; Smolentsev, V. P.; Yukhnevich, S. S.

2018-03-01

The new method was proposed for high-precision dimensional machining with a brush electrode when the true position of bundles of metal wire is adjusted by means of creating controlled centrifugal forces appeared due to the increased frequency of rotation of a tool. There are the ultimate values of circumferential velocity at which the bundles are pressed against a machined area of a workpiece in a stable manner despite the profile of the machined surface and variable stock of the workpiece. The special aspects of design of processing procedures for finishing standard parts, including components of products with low rigidity, are disclosed. The methodology of calculation and selection of processing modes which allow one to produce high-precision details and to provide corresponding surface roughness required to perform finishing operations (including the preparation of a surface for metal deposition) is presented. The production experience concerned with the use of high-speed combined machining with an unshaped tool electrode in knowledge-intensive branches of the machine-building industry for different types of production is analyzed. It is shown that the implementation of high-speed dimensional machining with an unshaped brush electrode allows one to expand the field of use of the considered process due to the application of a multipurpose tool in the form of a metal brush, as well as to obtain stable results of finishing and to provide the opportunities for long-term operation of the equipment without its changeover and readjustment.

System safety engineering in the development of advanced surface transportation vehicles

Science.gov (United States)

Arnzen, H. E.

1971-01-01

Applications of system safety engineering to the development of advanced surface transportation vehicles are described. As a pertinent example, the paper describes a safety engineering efforts tailored to the particular design and test requirements of the Tracked Air Cushion Research Vehicle (TACRV). The test results obtained from this unique research vehicle provide significant design data directly applicable to the development of future tracked air cushion vehicles that will carry passengers in comfort and safety at speeds up to 300 miles per hour.

Design, construction and testing of annular diffusers for high speed civil transportation combustor applications

Science.gov (United States)

Okhio, Cyril B.

1995-01-01

A theoretical and an experimental design study of subsonic flow through curved-wall annular diffusers is being carried out in order to establish the most pertinent design parameters for such devices and the implications of their application in the design of engine components in the aerospace industries. This investigation consists of solving numerically the full Navier Stokes and Continuity equations for the time-mean flow. Various models of turbulence are being evaluated for adoption throughout the study and comparisons would be made with experimental data where they exist. Assessment of diffuser performance based on the dissipated mechanical energy would also be made. The experimental work involves the application of Computer Aided Design software tool to the development of a suitable annular diffuser geometry and the subsequent downloading of such data to a CNC machine at Central State University. The results of the investigations are expected to indicate that more cost effective component design of such devices as effective component design of such devices as diffusers which normally contain complex flows can still be achieved. In this regard a review paper was accepted and presented at the First International Conference on High Speed Civil Transportation Research held at North Carolina A&T in December of 1994.

Nanocrystalline Ni-Co Alloy Synthesis by High Speed Electrodeposition

Directory of Open Access Journals (Sweden)

Jamaliah Idris

2013-01-01

Full Text Available Electrodeposition of nanocrystals is economically and technologically viable production path for the synthesis of pure metals and alloys both in coatings and bulk form. The study presents nanocrystalline Ni-Co alloy synthesis by high speed electrodeposition. Nanocrystalline Ni-Co alloys coatings were prepared by direct current (DC and deposited directly on steel and aluminum substrates without any pretreatment, using high speed electrodeposition method. The influence of the electrolysis parameters, such as cathodic current density and temperature at constant pH, on electrodeposition and microstructure of Ni-Co alloys were examined. A homogeneous surface morphology was obtained at all current densities of the plated samples, and it was evident that the current density and temperature affect the coating thickness of Ni-Co alloy coatings.

A Cloud-Computing-Based Data Placement Strategy in High-Speed Railway

Directory of Open Access Journals (Sweden)

Hanning Wang

2012-01-01

Full Text Available As an important component of China’s transportation data sharing system, high-speed railway data sharing is a typical application of data-intensive computing. Currently, most high-speed railway data is shared in cloud computing environment. Thus, there is an urgent need for an effective cloud-computing-based data placement strategy in high-speed railway. In this paper, a new data placement strategy named hierarchical structure data placement strategy is proposed. The proposed method combines the semidefinite programming algorithm with the dynamic interval mapping algorithm. The semi-definite programming algorithm is suitable for the placement of files with various replications, ensuring that different replications of a file are placed on different storage devices, while the dynamic interval mapping algorithm ensures better self-adaptability of the data storage system. A hierarchical data placement strategy is proposed for large-scale networks. In this paper, a new theoretical analysis is provided, which is put in comparison with several other previous data placement approaches, showing the efficacy of the new analysis in several experiments.

Strategy Planning of Technology Development for High Speed Railways : Electrical Parts

Energy Technology Data Exchange (ETDEWEB)

Kim, Y. J.; Kim, K. H.; Rim, G. H.; Ha, H. D.; Park, K. Y.; Lee, J. D.; Kang, D. H. [Korea Electrotechnology Research Institute (Korea, Republic of)

1996-11-01

At the beginning of 1996, Government has set up the Technology Development Program for High Speed Railways as a national project. Accordingly, the detailed action planning has been established with the collaboration works between Ministry of Construction and Transport and Ministry of Commerce and Trade. On the other hand, the current technology status of domestic manufacturer and many related organizations in Korea only reveals the lack of capabilities in producing the high speed trains. Without the technology transfer programs from the advanced foreign manufacturer (GEC-Alsthom), the domestic manufacturers could not produce HSR. Korea Electrotechnology Research Institute has steered the study to integrate the domestic engineering and technology units specialized in the diversified areas by formulating the feasible collaboration structure between KERI and many organizations on the technology basis. The long term action planning both with the strategic guide and on the technology basis shall be the key function to upgrade the current technology status feasibly for development of the advanced high speed train of 350 km/h. (author). refs., figs., tabs.

Investigation of the effect of cutting speed on the Surface Roughness parameters in CNC End Milling using Artificial Neural Network

International Nuclear Information System (INIS)

Al Hazza, Muataz H F; Adesta, Erry Y T

2013-01-01

This research presents the effect of high cutting speed on the surface roughness in the end milling process by using the Artificial Neural Network (ANN). An experimental investigation was conducted to measure the surface roughness for end milling. A set of sparse experimental data for finish end milling on AISI H13 at hardness of 48 HRC have been conducted. The artificial neural network (ANN) was applied to simulate and study the effect of high cutting speed on the surface roughness

High speed heterostructure devices

CERN Document Server

Beer, Albert C; Willardson, R K; Kiehl, Richard A; Sollner, T C L Gerhard

1994-01-01

Volume 41 includes an in-depth review of the most important, high-speed switches made with heterojunction technology. This volume is aimed at the graduate student or working researcher who needs a broad overview andan introduction to current literature. Key Features * The first complete review of InP-based HFETs and complementary HFETs, which promise very low power and high speed * Offers a complete, three-chapter review of resonant tunneling * Provides an emphasis on circuits as well as devices.

Surface Effect on Oil Transportation in Nanochannel: a Molecular Dynamics Study.

Science.gov (United States)

Zheng, Haixia; Du, Yonggang; Xue, Qingzhong; Zhu, Lei; Li, Xiaofang; Lu, Shuangfang; Jin, Yakang

2017-12-01

In this work, we investigate the dynamics mechanism of oil transportation in nanochannel using molecular dynamics simulations. It is demonstrated that the interaction between oil molecules and nanochannel has a great effect on the transportation properties of oil in nanochannel. Because of different interactions between oil molecules and channel, the center of mass (COM) displacement of oil in a 6-nm channel is over 30 times larger than that in a 2-nm channel, and the diffusion coefficient of oil molecules at the center of a 6-nm channel is almost two times more than that near the channel surface. Besides, it is found that polarity of oil molecules has the effect on impeding oil transportation, because the electrostatic interaction between polar oil molecules and channel is far larger than that between nonpolar oil molecules and channel. In addition, channel component is found to play an important role in oil transportation in nanochannel, for example, the COM displacement of oil in gold channel is very few due to great interaction between oil and gold substrate. It is also found that nano-sized roughness of channel surface greatly influences the speed and flow pattern of oil. Our findings would contribute to revealing the mechanism of oil transportation in nanochannels and therefore are very important for design of oil extraction in nanochannels.

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process

Directory of Open Access Journals (Sweden)

N. V. Dhandapani

2015-01-01

Full Text Available This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process.

Science.gov (United States)

Dhandapani, N V; Thangarasu, V S; Sureshkannan, G

2015-01-01

This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

South African performance based standards (PBS) vehicle to transport steel pipes

CSIR Research Space (South Africa)

Dessein, T

2010-03-01

Full Text Available measures the vehicle?s rollover stability. Rearward Amplification (RA) ? Measures the degree to which the lateral accelerations experienced by trailing units are amplified in comparison to that of the towing unit in a high speed evasive single lane...-speed 90? turn high-speed travel along a 1.0km long straight road with uneven road surface a pulse-steer test HVTT11: A South African PBS Vehicle to Transport Pipes 10 a constant radius turn at slowly increasing speed an evasive lane change...

High-Speed Rail and Local Land Development : Case Studies in London and Las Vegas

Science.gov (United States)

2017-11-01

The efficacy of a high-speed rail system depends, in part, upon locating rail stations close to urban centers and integrating them into broader transportation networks and the urban realm. In addition, through economies of agglomeration, successful h...

SU-D-213AB-06: Surface Texture and Insertion Speed Effect on Needle Friction.

Science.gov (United States)

Abdullah, A; Golecki, C; Barnett, A; Moore, J

2012-06-01

High frictional forces between the needle surface and tissue cause tissue deflection which hinders accurate needle placement for procedures such as brachytherapy and needle biopsy. Accurate needle placement isimportant to maximize procedure efficacy. This work investigates how needle surface roughness and insertion speed affect the frictional forcebetween a needle and tissue. A friction experiment was conducted to measure the force of friction between bovine liver and three 11 gauge needles having Ra surface roughness of 3.43, 1.33, and 0.2 μm. Each of the three needles were mounted on a linear slide and were advanced and retracted through bovine liver at speeds of 50, 100, 150, and 200 mm/s for a total of 12 trials. In each trial the needle was advanced and retracted in 10 cycles producing a steady state insertion force and a steady state retraction force for each cycle. A force sensor connecting the needle to the linear slide recorded the resistance force of the needle sliding through the liver. The liver was mounted in a box with a pneumatic cylinder which compressed the liver sample by 11.65 kPa. The roughest needle (Ra = 3.43 μm) on average produced 68, 73, 74, and 73% lower friction force than the smoothest needle (Ra = 0.2 μm) for the speeds of 50, 100, 150, and 200mm/s, respectively. The second roughest needle (Ra = 1.33 μm) on average produced 25, 45, 60 and 64% lower friction force than the smoothest needle (Ra = 0.2 μm) for the speeds of 50, 100, 150, and 200 mm/s, respectively. Rougher needle surface texture and higher insertion speed reduced frictional forces between the tissue and the needle. Future studies will examine how frictional forces can be modeled and predicted given surface texture and insertion speed. © 2012 American Association of Physicists in Medicine.

Impact of Increased Football Field Width on Player High-Speed Collision Rate.

Science.gov (United States)

Joseph, Jacob R; Khalsa, Siri S; Smith, Brandon W; Park, Paul

2017-07-01

High-acceleration head impact is a known risk for mild traumatic brain injury (mTBI) based on studies using helmet accelerometry. In football, offensive and defensive players are at higher risk of mTBI due to increased speed of play. Other collision sport studies suggest that increased playing surface size may contribute to reductions in high-speed collisions. We hypothesized that wider football fields lead to a decreased rate of high-speed collisions. Computer football game simulation was developed using MATLAB. Four wide receivers were matched against 7 defensive players. Each offensive player was randomized to one of 5 typical routes on each play. The ball was thrown 3 seconds into play; ball flight time was 2 seconds. Defensive players were delayed 0.5 second before reacting to ball release. A high-speed collision was defined as the receiver converging with a defensive player within 0.5 second of catching the ball. The simulation counted high-speed collisions for 1 team/season (65 plays/game for 16 games/season = 1040 plays/season) averaged during 10 seasons, and was validated against existing data using standard field width (53.3 yards). Field width was increased in 1-yard intervals up to 58.3 yards. Using standard field width, 188 ± 4 high-speed collisions were seen per team per season (18% of plays). When field width increased by 3 yards, high-speed collision rate decreased to 135 ± 3 per team per season (28% decrease; P football field width can lead to substantial decline in high-speed collisions, with potential for reducing instances of mTBI in football players. Copyright © 2017 Elsevier Inc. All rights reserved.

Learning Traffic as Images: A Deep Convolutional Neural Network for Large-Scale Transportation Network Speed Prediction.

Science.gov (United States)

Ma, Xiaolei; Dai, Zhuang; He, Zhengbing; Ma, Jihui; Wang, Yong; Wang, Yunpeng

2017-04-10

This paper proposes a convolutional neural network (CNN)-based method that learns traffic as images and predicts large-scale, network-wide traffic speed with a high accuracy. Spatiotemporal traffic dynamics are converted to images describing the time and space relations of traffic flow via a two-dimensional time-space matrix. A CNN is applied to the image following two consecutive steps: abstract traffic feature extraction and network-wide traffic speed prediction. The effectiveness of the proposed method is evaluated by taking two real-world transportation networks, the second ring road and north-east transportation network in Beijing, as examples, and comparing the method with four prevailing algorithms, namely, ordinary least squares, k-nearest neighbors, artificial neural network, and random forest, and three deep learning architectures, namely, stacked autoencoder, recurrent neural network, and long-short-term memory network. The results show that the proposed method outperforms other algorithms by an average accuracy improvement of 42.91% within an acceptable execution time. The CNN can train the model in a reasonable time and, thus, is suitable for large-scale transportation networks.

14 CFR 23.253 - High speed characteristics.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 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...

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

International Nuclear Information System (INIS)

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 SO 2 , CO, NO X , VOC, and PM 10 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 SO 2 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.

Sampling optimization for high-speed weigh-in-motion measurements using in-pavement strain-based sensors

International Nuclear Information System (INIS)

Zhang, Zhiming; Huang, Ying; Bridgelall, Raj; Palek, Leonard; Strommen, Robert

2015-01-01

Weigh-in-motion (WIM) measurement has been widely used for weight enforcement, pavement design, freight management, and intelligent transportation systems to monitor traffic in real-time. However, to use such sensors effectively, vehicles must exit the traffic stream and slow down to match their current capabilities. Hence, agencies need devices with higher vehicle passing speed capabilities to enable continuous weight measurements at mainline speeds. The current practices for data acquisition at such high speeds are fragmented. Deployment configurations and settings depend mainly on the experiences of operation engineers. To assure adequate data, most practitioners use very high frequency measurements that result in redundant samples, thereby diminishing the potential for real-time processing. The larger data memory requirements from higher sample rates also increase storage and processing costs. The field lacks a sampling design or standard to guide appropriate data acquisition of high-speed WIM measurements. This study develops the appropriate sample rate requirements as a function of the vehicle speed. Simulations and field experiments validate the methods developed. The results will serve as guidelines for future high-speed WIM measurements using in-pavement strain-based sensors. (paper)

Sampling optimization for high-speed weigh-in-motion measurements using in-pavement strain-based sensors

Science.gov (United States)

Zhang, Zhiming; Huang, Ying; Bridgelall, Raj; Palek, Leonard; Strommen, Robert

2015-06-01

Weigh-in-motion (WIM) measurement has been widely used for weight enforcement, pavement design, freight management, and intelligent transportation systems to monitor traffic in real-time. However, to use such sensors effectively, vehicles must exit the traffic stream and slow down to match their current capabilities. Hence, agencies need devices with higher vehicle passing speed capabilities to enable continuous weight measurements at mainline speeds. The current practices for data acquisition at such high speeds are fragmented. Deployment configurations and settings depend mainly on the experiences of operation engineers. To assure adequate data, most practitioners use very high frequency measurements that result in redundant samples, thereby diminishing the potential for real-time processing. The larger data memory requirements from higher sample rates also increase storage and processing costs. The field lacks a sampling design or standard to guide appropriate data acquisition of high-speed WIM measurements. This study develops the appropriate sample rate requirements as a function of the vehicle speed. Simulations and field experiments validate the methods developed. The results will serve as guidelines for future high-speed WIM measurements using in-pavement strain-based sensors.

Profile parameters of wheelset detection for high speed freight train

Science.gov (United States)

Yang, Kai; Ma, Li; Gao, Xiaorong; Wang, Li

2012-04-01

Because of freight train, in China, transports goods on railway freight line throughout the country, it does not depart from or return to engine shed during a long phase, thus we cannot monitor the quality of wheel set effectively. This paper provides a system which uses leaser and high speed camera, applies no-contact light section technology to get precise wheel set profile parameters. The paper employs clamping-track method to avoid complex railway ballast modification project. And detailed descript an improved image-tracking algorithm to extract central line from profile curve. For getting one pixel width and continuous line of the profile curve, uses local gray maximum points as direction control points to direct tracking direction. The results based on practical experiment show the system adapted to detection environment of high speed and high vibration, and it can effectively detect the wheelset geometric parameters with high accuracy. The system fills the gaps in wheel set detection for freight train in main line and has an enlightening function on monitoring the quality of wheel set.

Investigation of Inner Loop Flight Control Strategies for High-Speed Research

Science.gov (United States)

Newman, Brett; Kassem, Ayman

1999-01-01

This report describes the activities and findings conducted under contract NAS1-19858 with NASA Langley Research Center. Subject matter is the investigation of suitable flight control design methodologies and solutions for large, flexible high-speed vehicles. Specifically, methodologies are to address the inner control loops used for stabilization and augmentation of a highly coupled airframe system possibly involving rigid-body motion, structural vibrations, unsteady aerodynamics, and actuator dynamics. Techniques considered in this body of work are primarily conventional-based, and the vehicle of interest is the High-Speed Civil Transport (HSCT). Major findings include 1) current aeroelastic vehicle modeling procedures require further emphasis and refinement, 2) traditional and nontraditional inner loop flight control strategies employing a single feedback loop do not appear sufficient for highly flexible HSCT class vehicles, 3) inner loop flight control systems will, in all likelihood, require multiple interacting feedback loops, and 4) Ref. H HSCT configuration presents major challenges to designing acceptable closed-loop flight dynamics.

Modelling Of Residual Stresses Induced By High Speed Milling Process

International Nuclear Information System (INIS)

Desmaison, Olivier; Mocellin, Katia; Jardin, Nicolas

2011-01-01

Maintenance processes used in heavy industries often include high speed milling operations. The reliability of the post-process material state has to be studied. Numerical simulation appears to be a very interesting way to supply an efficient residual stresses (RS) distribution prediction.Because the adiabatic shear band and the serrated chip shaping are features of the austenitic stainless steel high speed machining, a 2D high speed orthogonal cutting model is briefly presented. This finite element model, developed on Forge registered software, is based on data taken from Outeiro and al.'s paper [1]. A new behaviour law fully coupling Johnson-Cook's constitutive law and Latham and Cockcroft's damage model is detailed in this paper. It ensures results that fit those found in literature.Then, the numerical tools used on the 2D model are integrated to a 3D high speed milling model. Residual stresses distribution is analysed, on the surface and into the depth of the material. Various revolutions and passes of the two teeth hemispheric mill on the workpiece are simulated. Thus the sensitivity of the residual stresses generation to the cutting conditions can be discussed. In order to validate the 3D model, a comparison of the cutting forces measured by EDF R and D to those given by numerical simulations is achieved.

High-Speed Photography

International Nuclear Information System (INIS)

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

1998-01-01

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 1998 Society of Photo-Optical Instrumentation Engineers

Study on the machinability characteristics of superalloy Inconel 718 during high speed turning

International Nuclear Information System (INIS)

Thakur, D.G.; Ramamoorthy, B.; Vijayaraghavan, L.

2009-01-01

The present paper is an attempt of an experimental investigation on the machinability of superalloy, Inconel 718 during high speed turning using tungsten carbide insert (K20) tool. The effect of machining parameters on the cutting force, specific cutting pressure, cutting temperature, tool wear and surface finish criteria were investigated during the experimentation. The machining parameters have been optimized by measuring forces. The effect of machining parameters on the tool wear was examined through SEM micrographs. During high speed turning acoustic emission signal were collected and analyzed to understand the effect of cutting parameters during online. The research work findings will also provide useful economic machining solution by utilizing economical tungsten carbide tooling during high speed processing of Inconel 718, which is otherwise usually machined by costly PCD or CBN tools. The present approach and results will be helpful for understanding the machinability of Inconel 718 during high speed turning for the manufacturing engineers

High speed translocation of /sup 86/Rb in the phloem of Tradescantia viridis

Energy Technology Data Exchange (ETDEWEB)

Penot, M.

1976-01-01

An autoradiographic study of the rooted shoots of Tradescantia viridis showed a high speed translocation of /sup 86/Rb applied to a leaf for short periods of time (5 to 2.5 min). The speed of this translocation (between 840 and 1.440 cm h/sup -1/) speaks for the existence of a very rapid phloem component translocating ions to an active sink, represented here by the growing roots. Pretreatment with cycloheximide (48 h, 50 mg 1/sup -1/) decreases the quantity of this long distance transport but not the velocity.

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

Science.gov (United States)

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.

High-Speed Train Stop-Schedule Optimization Based on Passenger Travel Convenience

OpenAIRE

Dingjun Chen; Shaoquan Ni; Chang’an Xu; Hongxia Lv; Simin Wang

2016-01-01

The stop-schedules for passenger trains are important to the operation planning of high-speed trains, and they decide the quality of passenger service and the transportation efficiency. This paper analyzes the specific manifestation of passenger travel convenience and proposes the concepts of interstation accessibility and degree of accessibility. In consideration of both the economic benefits of railway corporations and the travel convenience of passengers, a multitarget optimization model i...

Assessment of CHSST maglev for U.S. urban transportation

Science.gov (United States)

2002-07-01

This report provides an assessment of the Urban Maglev system proposed by the Maglev Urban Systems Associates MUSA team for application in the United States. The proposed system is the Japanese Chubu high speed surface transportation (HSST) Maglev wh...

A reference Pelton turbine - High speed visualization in the rotating frame

Science.gov (United States)

Solemslie, Bjørn W.; Dahlhaug, Ole G.

2016-11-01

To enable a detailed study the flow mechanisms effecting the flow within the reference Pelton runner designed at the Waterpower Laboratory (NTNLT) a flow visualization system has been developed. The system enables high speed filming of the hydraulic surface of a single bucket in the rotating frame of reference. It is built with an angular borescopes adapter entering the turbine along the rotational axis and a borescope embedded within a bucket. A stationary high speed camera located outside the turbine housing has been connected to the optical arrangement by a non-contact coupling. The view point of the system includes the whole hydraulic surface of one half of a bucket. The system has been designed to minimize the amount of vibrations and to ensure that the vibrations felt by the borescope are the same as those affecting the camera. The preliminary results captured with the system are promising and enable a detailed study of the flow within the turbine.

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

Science.gov (United States)

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…

High-speed data search

Science.gov (United States)

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.

A field study of flow turbulence and sediment transport dynamics on a beach surface in the lee of a coastal foredune under offshore winds

Science.gov (United States)

Baas, A. C.; Jackson, D.; Cooper, J. A.; Lynch, K.; Delgado-Fernandez, I.; Beyers, M.; Lee, Z. S.

2010-12-01

The past decade has seen a growing body of research on the relation between turbulence in the wind and the resultant transport of sediment over active sand surfaces. Widespread use of sonic anemometry and high-frequency sand transport sensors and traps have facilitated recent field studies over dunes and beach surfaces, to move beyond monitoring of mean wind speed and bulk transport to more detailed measurements at much higher spatio-temporal resolutions. In this paper we present results of a field study conducted in the recirculation flow and re-attachment zone on a beach behind a foredune at Magilligan Strand, Northern Ireland. The offshore winds over the foredune at this site are associated with flow separation and reversal located over the beach surface in the lee of the dune row, often strong enough to induce sand transport toward the toe of the foredune (‘against’ the overall offshore flow). The re-attachment and recirculation zone are associated with strongly turbulent fluid flow and complex streamlines that do not follow the underlying topography. High frequency (25 Hz) wind and sand transport data were collected at a grid of point locations distributed over the beach surface between 35 m to 55 m distance from the 10 m high dune crest, using ultrasonic anemometers at 0.5 m height and co-located load cell traps and Safires at the bed surface. The wind data are used to investigate the role of Reynolds shear stresses and quadrant analysis techniques for identifying burst-sweep events in relation to sand transport events. This includes an assessment of the issues involved with data rotations for yaw, pitch, and roll corrections relative to complex flow streamlines, and the subsequently derived turbulence parameters based on fluctuating vector components (u’, v’, w’). Results illustrate how transport may exist under threshold mean velocities because of the role played by coherent flow structures, and the findings corroborate previous findings that

33 CFR 84.24 - High-speed craft.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 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...

High-speed VCSEL-based optical interconnects

Science.gov (United States)

Ishak, Waguih S.

2001-11-01

Vertical Cavity Surface Emitting Lasers (VCSEL) have made significant inroads into commercial realization especially in the area of data communications. Single VCSEL devices are key components in Gb Ethernet Transceivers. A multi-element VCSEL array is the key enabling technology for high-speed multi Gb/s parallel optical interconnect modules. In 1996, several companies introduced a new generation of fiber optic products based VCSEL technology such as multimode fiber transceivers for the ANSI Fiber Channel and Gigabit Ethernet IEEE 802.3 standards. VCSELs offer unique advantages over its edge-emitting counterparts in several areas. These include low-cost (LED-like) manufacturability, low current operation and array integrability. As data rates continue to increase, VCSELs offer the advantage of being able to provide the highest modulation bandwidth per milliamp of modulation current. Currently, most of the VCSEL-based products use short (780 - 980 nm) wavelength lasers. However, significant research efforts are taking place at universities and industrial research labs around the world to develop reliable, manufacturable and high-power long (1300 - 1550 nm) wavelength VCSELs. These lasers will allow longer (several km) transmission distances and will help alleviate some of the eye-safety issues. Perhaps, the most important advantage of VCSELs is the ability to form two-dimensional arrays much easier than in the case of edge-emitting lasers. These arrays (single and two-dimensional) will allow a whole new family of applications, specifically in very high-speed computer and switch interconnects.

Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

Directory of Open Access Journals (Sweden)

Jie Zhou

2015-01-01

Full Text Available With the demand for turbomachinery to operate at higher speeds, loads, and power, fluid film bearings that support turbomachinery must be capable of operating in these more demanding applications. Thrust bearings operating at high speeds and loads can experience high surface temperatures and thin fluid film thickness. Typically, babbitt (white metal is the bearing lining material for most turbomachinery bearings but is limited in operating temperature and allowable film thickness. Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP. Test results of polymer lined thrust bearings subjected to modern turbomachinery speeds and loads are presented and compared to babbitt lined bearings of the same design and under similar conditions. The test results show polymer lined thrust bearings can operate at higher bearing unit loads than babbitt.

High-Speed 3D Printing of Millimeter-Size Customized Aspheric Imaging Lenses with Sub 7 nm Surface Roughness.

Science.gov (United States)

Chen, Xiangfan; Liu, Wenzhong; Dong, Biqin; Lee, Jongwoo; Ware, Henry Oliver T; Zhang, Hao F; Sun, Cheng

2018-05-01

Advancements in three-dimensional (3D) printing technology have the potential to transform the manufacture of customized optical elements, which today relies heavily on time-consuming and costly polishing and grinding processes. However the inherent speed-accuracy trade-off seriously constrains the practical applications of 3D-printing technology in the optical realm. In addressing this issue, here, a new method featuring a significantly faster fabrication speed, at 24.54 mm 3 h -1 , without compromising the fabrication accuracy required to 3D-print customized optical components is reported. A high-speed 3D-printing process with subvoxel-scale precision (sub 5 µm) and deep subwavelength (sub 7 nm) surface roughness by employing the projection micro-stereolithography process and the synergistic effects from grayscale photopolymerization and the meniscus equilibrium post-curing methods is demonstrated. Fabricating a customized aspheric lens 5 mm in height and 3 mm in diameter is accomplished in four hours. The 3D-printed singlet aspheric lens demonstrates a maximal imaging resolution of 373.2 lp mm -1 with low field distortion less than 0.13% across a 2 mm field of view. This lens is attached onto a cell phone camera and the colorful fine details of a sunset moth's wing and the spot on a weevil's elytra are captured. This work demonstrates the potential of this method to rapidly prototype optical components or systems based on 3D printing. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Changes of indicators of high-speed and high-speed and power preparedness at volleyball players of 12–13 years old

Directory of Open Access Journals (Sweden)

Oleg Shevchenko

2016-04-01

Full Text Available Purpose: to define changes of indicators of high-speed and high-speed and power preparedness of volleyball players of 12–13 years old. Material & Methods: the test exercises, which are recommended by the training program of CYSS on volleyball, were used for the definition of the level of development of high-speed and high-speed and power abilities of volleyball players. 25 young volleyball players from the group of the previous basic preparation took part in the experiment. Sports experience of sportsmen is 3–4 years. The analysis of scientifically-methodical literature, pedagogical testing, pedagogical experiment, methods of mathematical statistics were carried out. Results: the analyzed level of high-speed and high-speed and power abilities of volleyball players. Conclusions: the results had reliable changes (t=2,2–2,4 at р<0,05 of the level of high-speed and high-speed and power abilities of volleyball players of 12–13years old in the experimental group at the end of the experiment, except run on 30 m that demonstrates a positive influence of application of special exercises in the educational-training process.

1995 NASA High-Speed Research Program Sonic Boom Workshop. Volume 2; Configuration Design, Analysis, and Testing

Science.gov (United States)

Baize, Daniel G. (Editor)

1999-01-01

The High-Speed Research Program and NASA Langley Research Center sponsored the NASA High-Speed Research Program Sonic Boom Workshop on September 12-13, 1995. The workshop was designed to bring together NASAs scientists and engineers and their counterparts in industry, other Government agencies, and academia working together in the sonic boom element of NASAs High-Speed Research Program. Specific objectives of this workshop were to: (1) report the progress and status of research in sonic boom propagation, acceptability, and design; (2) promote and disseminate this technology within the appropriate technical communities; (3) help promote synergy among the scientists working in the Program; and (4) identify technology pacing, the development C, of viable reduced-boom High-Speed Civil Transport concepts. The Workshop was organized in four sessions: Sessions 1 Sonic Boom Propagation (Theoretical); Session 2 Sonic Boom Propagation (Experimental); Session 3 Acceptability Studies-Human and Animal; and Session 4 - Configuration Design, Analysis, and Testing.

Reducing Heating In High-Speed Cinematography

Science.gov (United States)

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.

High-speed high-efficiency 500-W cw CO2 laser hermetization of metal frames of microelectronics devices

Science.gov (United States)

Levin, Andrey V.

1996-04-01

High-speed, efficient method of laser surface treatment has been developed using (500 W) cw CO2 laser. The principal advantages of CO2 laser surface treatment in comparison with solid state lasers are the basis of the method. It has been affirmed that high efficiency of welding was a consequence of the fundamental properties of metal-IR-radiation (10,6 mkm) interaction. CO2 laser hermetization of metal frames of microelectronic devices is described as an example of the proposed method application.

High speed data acquisition

International Nuclear Information System (INIS)

Cooper, P.S.

1997-07-01

A general introduction to high speed data acquisition system techniques in modern particle physics experiments is given. Examples are drawn from the SELEX(E78 1) high statistics charmed baryon production and decay experiment now taking data at Fermilab

High-Speed Scanning Interferometer Using CMOS Image Sensor and FPGA Based on Multifrequency Phase-Tracking Detection

Science.gov (United States)

Ohara, Tetsuo

2012-01-01

A sub-aperture stitching optical interferometer can provide a cost-effective solution for an in situ metrology tool for large optics; however, the currently available technologies are not suitable for high-speed and real-time continuous scan. NanoWave s SPPE (Scanning Probe Position Encoder) has been proven to exhibit excellent stability and sub-nanometer precision with a large dynamic range. This same technology can transform many optical interferometers into real-time subnanometer precision tools with only minor modification. The proposed field-programmable gate array (FPGA) signal processing concept, coupled with a new-generation, high-speed, mega-pixel CMOS (complementary metal-oxide semiconductor) image sensor, enables high speed (>1 m/s) and real-time continuous surface profiling that is insensitive to variation of pixel sensitivity and/or optical transmission/reflection. This is especially useful for large optics surface profiling.

Wake flow characteristics at high wind speed

DEFF Research Database (Denmark)

Aagaard Madsen, Helge; Larsen, Torben J.; Larsen, Gunner Chr.

2016-01-01

Wake flow characteristic at high wind speeds is the main subject of this paper. Although the wake losses decrease at high wind speeds it has been found in a recent study that for multiple wake inflow the increase in loading due to wake effects are substantial even at wind speeds well above rated ...

Application Of CO2 Lasers To High Speed Blanking

Science.gov (United States)

Grenier, L. E.

1986-11-01

While laser cutting of sheetmetal has attained wide acceptance in the automotive industry for the purposes of prototyping and very limited preproduction work, the production rates possible with currently available systems have precluded the use of this technique in a production environment. The device design to be described embodies a high speed X-Y positioner carrying a cutting head with limited Z-axis capability. This approach confers two main benefits, first, production rate is limited only by laser power, since the positioner technology selected will permit movement at rates up to 1.5 m/s (60 in/s), second, the use of a high speed non-contact surface follower to control the Z-axis movement reduces the need to clamp the workpiece rigidly to a precision reference surface. The realized reduction of the clamping requirement permits some latitude in the feed methods that can be employed, allowing the use of coil or sheet feeding as appropriate. The author will provide estimated production rates for the proposed design and demonstrate that a suitable choice of laser source and material feed will permit the production of parts at a rate and cost comparable to conventional blanking with the advantage of much greater flexibility and reduced retooling time.

Proposed high speed pellet injection system 'HIPEL' for Large Helical Device

International Nuclear Information System (INIS)

Sudo, S.; Kanno, M.; Kaneko, H.; Saka, S.; Shirai, T.; Baba, T.

1993-11-01

From the results of the simulation study including pellet ablation and 1-D transport code, it is found that a high speed pellet injector with pellet velocity of more than 3 km/s is necessary for the penetration of the pellet with diameter of 3 mm into the core region under the expected plasma condition of Large Helical Device (LHD) of heliotron/stellarator type with superconducting coils at NIFS in Japan. Therefore, a two stage pellet injector was constructed and tested successfully in order to obtain the pellet velocity range of 3 km/s. Based upon the above results, a high speed flexible multiple-pellet injection system 'HIPEL' for LHD is proposed. HIPEL consists of independent (1) 10 two-stage gun barrels and (2) 10 single-stage gun barrels. It has multi purposes such as refueling and flexible density profile control, diagnostics and the other functions. (author)

High Speed Civil Transport (HSCT) Isolated Nacelle Transonic Boattail Drag Study and Results Using Computational Fluid Dynamics (CFD)

Science.gov (United States)

Midea, Anthony C.; Austin, Thomas; Pao, S. Paul; DeBonis, James R.; Mani, Mori

2005-01-01

Nozzle boattail drag is significant for the High Speed Civil Transport (HSCT) and can be as high as 25 percent of the overall propulsion system thrust at transonic conditions. Thus, nozzle boattail drag has the potential to create a thrust drag pinch and can reduce HSCT aircraft aerodynamic efficiencies at transonic operating conditions. In order to accurately predict HSCT performance, it is imperative that nozzle boattail drag be accurately predicted. Previous methods to predict HSCT nozzle boattail drag were suspect in the transonic regime. In addition, previous prediction methods were unable to account for complex nozzle geometry and were not flexible enough for engine cycle trade studies. A computational fluid dynamics (CFD) effort was conducted by NASA and McDonnell Douglas to evaluate the magnitude and characteristics of HSCT nozzle boattail drag at transonic conditions. A team of engineers used various CFD codes and provided consistent, accurate boattail drag coefficient predictions for a family of HSCT nozzle configurations. The CFD results were incorporated into a nozzle drag database that encompassed the entire HSCT flight regime and provided the basis for an accurate and flexible prediction methodology.

Field-tested technology for gas compression: using high-speed induction motors to replace conventional solutions

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Karina Velloso; Pradurat, Jean Francois [Institut National Polytechnique de Lorraine (INPL), Nancy (France). Converteam Rotating Machines Division

2009-07-01

Industry leaders are all concerned about rationalization of electric power use, increase of efficiency and flexibility, environmental impact, installations size and maintenance efforts diminution. The high-speed induction motors are a good solution when addressing these parameters. How this technology works and how using it can help pipelines operators meet growing operational and environmental challenges is the main subject of this paper, that also explain how it can be used to replace conventional solutions. As a conclusion the future opportunities of electric high-speed drive systems application in production, transport and storage for natural gas industry are going to be discussed. (author)

Direct measurements of air layer profiles under impacting droplets using high-speed color interferometry

NARCIS (Netherlands)

van der Veen, Roeland; Tran, Tuan; Lohse, Detlef; Sun, Chao

2012-01-01

A drop impacting on a solid surface deforms before the liquid makes contact with the surface. We directly measure the time evolution of the air layer profile under the droplet using high-speed color interferometry, obtaining the air layer thickness before and during the wetting process. Based on the

Radon transport processes below the earth's surface

International Nuclear Information System (INIS)

Wilkening, M.

1980-01-01

Processes by which 222 Rn is transported from the soil to the earth's surface are reviewed. The mechanisms effective in transporting 222 Rn to the surface are related to the size and configuration of the spaces occupied by the soil gas which may vary from molecular interstices to large underground caverns. The near-surface transport processes are divided into two categories: (1) a microscopic process that includes molecular diffusion and viscous flow in fine capillaries and (2) macroscopic flow in fissures and channels. Underground air rich in 222 Rn can also reach the surface through cracks, fissures, and underground channels. This type of transport is shown for (1) a horizontal tunnel penetrating a fractured hillside, (2) a large underground cave, and (3) volcanic activity. Pressure differentials having various natural origins and thermal gradients are responsible for the transport in these examples. 222 Rn transport by ordinary molecular diffusion appears to be the dominant process

14 CFR 25.253 - High-speed characteristics.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false High-speed characteristics. 25.253 Section...-speed characteristics. (a) Speed increase and recovery characteristics. The following speed increase and recovery characteristics must be met: (1) Operating conditions and characteristics likely to cause...

Wetting dynamics at high values of contact line speed

OpenAIRE

Пономарев, К. О.; Феоктистов, Дмитрий Владимирович; Орлова, Евгения Георгиевна

2015-01-01

Experimental results analyses of dynamic contact angle change under the conditions of substrate wetting by distilled water at high values of the contact line speed was conducted. Three spreading modes for copper substrates with different roughness were selected: drop formation, spreading and equilibrium contact angle formation. Peculiarity of droplet spreading on superhydrophobic surface is found. It consists in a monotonic increase of the advancing dynamic contact angle. The effect of the dr...

A coordinate transform method for one-speed neutron transport in composite slabs

International Nuclear Information System (INIS)

Haidar, N.H.S.

1988-01-01

The optical path transformation is applied to reduce the one-speed neutron transport equation for a class of composite subcritical slabs to single-region problems. The class idealises, within the uncertainty of the one-speed model, a variety of practical situations such as U-D 2 O-C-Zr-Pb or Pu-U-Na-Fe symmetric reactor assemblies; which may possibly contain a symmetrically anisotropic neutron source. A closed form double series solution, which turns out to be quite convenient for design and optimisation purposes, has been obtained, in terms of discontinuous functions for the multi-regional angular flux by application of a double finite Legendre transform. Disadvantage factor evaluations for a U-C lattice cell resulting from a low-order P 0 P 1 approximation of this method are found to be in full agreement with hybrid diffusion-transport estimates. (author)

Lubrication and cooling for high speed gears

Science.gov (United States)

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.

New diffusion-like solutions of one-speed transport equations in spherical geometry

International Nuclear Information System (INIS)

Sahni, D.C.

1988-01-01

Stationary, one-speed, spherically symmetric transport equations are considered in a conservative medium. Closed-form expressions are obtained for the angular flux ψ(r, μ) that yield a total flux varying as 1/r by using Sonine transforms. Properties of this solution are studied and it is shown that the solution can not be identified as a diffusion mode solution of the transport equation. Limitations of the Sonine transform technique are noted. (author)

The use of high-speed imaging in education

Science.gov (United States)

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.

Observer Based Traction/Braking Control Design for High Speed Trains Considering Adhesion Nonlinearity

OpenAIRE

Cai, Wenchuan; Liao, Wenhao; Li, Danyong; Song, Yongduan

2014-01-01

Train traction/braking control, one of the key enabling technologies for automatic train operation, literally takes its action through adhesion force. However, adhesion coefficient of high speed train (HST) is uncertain in general because it varies with wheel-rail surface condition and running speed; thus, it is extremely difficult to be measured, which makes traction/braking control design and implementation of HSTs greatly challenging. In this work, force observers are applied to estimate t...

Transport of oxytetracycline, chlortetracycline, and ivermectin in surface runoff from irrigated pasture.

Science.gov (United States)

Bair, Daniel A; Popova, Ina E; Tate, Kenneth W; Parikh, Sanjai J

2017-09-02

The transport of oxytetracycline, chlortetracycline, and ivermectin from manure was assessed via surface runoff on irrigated pasture. Surface runoff plots in the Sierra Foothills of Northern California were used to evaluate the effects of irrigation water application rates, pharmaceutical application conditions, vegetative cover, and vegetative filter strip length on the pharmaceutical discharge in surface runoff. Experiments were designed to permit the maximum potential transport of pharmaceuticals to surface runoff water, which included pre-irrigation to saturate soil, trimming grass where manure was applied, and laying a continuous manure strip perpendicular to the flow of water. However, due to high sorption of the pharmaceuticals to manure and soil, less than 0.1% of applied pharmaceuticals were detected in runoff water. Results demonstrated an increase of pharmaceutical transport in surface runoff with increased pharmaceutical concentration in manure, the concentration of pharmaceuticals in runoff water remained constant with increased irrigation flow rate, and no appreciable decrease in pharmaceutical runoff was produced with the vegetative filter strip length increased from 30.5 to 91.5 cm. Most of the applied pharmaceuticals were retained in the manure or within the upper 5 cm of soil directly beneath the manure application sites. As this study evaluated conditions for high transport potential, the data suggest that the risk for significant chlortetracycline, oxytetracycline, and ivermectin transport to surface water from cattle manure on irrigated pasture is low.

Deformation-phase transformation coupling mechanism of white layer formation in high speed machining of FGH95 Ni-based superalloy

Energy Technology Data Exchange (ETDEWEB)

Du, Jin [School of Mechanical and Automotive Engineering, Qilu University of Technology, Jinan, Shandong 250353 (China); Liu, Zhanqiang, E-mail: melius@sdu.edu.cn [School of Mechanical Engineering, Shandong University, Jinan, Shandong 250061 (China); Key Laboratory of High Efficiency and Clean Mechanical Manufacture, Shandong University, Ministry of Education, Shandong (China); Lv, Shaoyu [School of Mechanical Engineering, Shandong University, Jinan, Shandong 250061 (China)

2014-02-15

Ni-based superalloy represents a significant metal portion of the aircraft critical structural and engine components. When these critical structural components in aerospace industry are manufactured with the objective to reach high reliability levels and excellent service performance, surface integrity is one of the most relevant parameter used for evaluating the quality of finish machined surfaces. In the study of surface integrity, the formation white layer is a very important research topic. The formation of white layer on the Ni-based superalloy machined surface will reduce the machined parts service performance and fatigue life. This paper was conducted to determine the effects of cutting speed on white layer formation in high speed machining of FGH95 Ni-based superalloy. Optical microscope, scanning electron microscope and X-ray diffraction were employed to analyze the elements and microstructures of white layer and bulk materials. The statistical analysis for grain numbers was executed to study the influence of cutting speed on the grain refinement in the machined surface. The investigation results showed that white layer exhibits significantly different microstructures with the bulk materials. It shows densification, no obvious structural features characteristic. The microstructure and phase of Ni-based solid solution changed during cutting process. The increase of cutting speed causes the increase of white layer thickness when the cutting speed is less than 2000 m/min. However, white layer thickness reduces with the cutting speed further increase. The higher the cutting speed, the more serious grains refinement in machined surface. 2-D FEM for machining FGH95 were carried out to simulate the cutting process and obtained the cutting temperature field, cutting strain field and strain rate field. The impact mechanisms of cutting temperature, cutting strain and strain rates on white layer formation were analyzed. At last, deformation-phase transformation

High-speed elevators controlled by inverters

Energy Technology Data Exchange (ETDEWEB)

Sakai, Yoshio; Takahashi, Hideaki; Nakamura, Kiyoshi; Kinoshita, Hiroshi

1988-10-25

The super-high-speed elevator with superiority to 300m/min of speed, requires both the large capacity power and wide range speed controls. Therefore, in order to materialize the smooth and quiet operation characteristics, by applying the inverter control, the low torque ripple control in the low frequency range and high frequency large capacity inverting for lowering the motor in noise are necessary with their being assured of reliability. To satisfy the above necessary items, together with the development of a sine wave pulse width and frequency modulation (PWM/PFM) control system, to more precisely enable the sine wave electric current control, and 3kHz switching power converter, using a 800A power transistor module, a supervoltage control circuit under the extraordinary condition was designed. As a result of commercializing a 360m/min super-high speed inverter elevator, the power source unit, due to the effect of high power factor, could be reduced by 30% in capacity and also the higher harmonic wave including ratio could be considerably lowered to the inferiority to 5%. 2 references, 7 figures, 1 table.

High - speed steel for precise cased tools

International Nuclear Information System (INIS)

Karwiarz, J.; Mazur, A.

2001-01-01

The test results of high-vanadium high - speed steel (SWV9) for precise casted tools are presented. The face -milling cutters of NFCa80A type have been tested in industrial operating conditions. An average life - time of SWV9 steel tools was 3-10 times longer compare to the conventional high - speed milling cutters. Metallography of SWB9 precise casted steel revealed beneficial for tool properties distribution of primary vanadium carbides in the steel matrix. Presented results should be a good argument for wide application of high - vanadium high - speed steel for precise casted tools. (author)

High-speed infrared imaging for material characterization in experimental mechanics experiments

Science.gov (United States)

Gagnon, Marc-André; Marcotte, Frédérick; Lagueux, Philippe; Farley, Vincent; Guyot, Éric; Morton, Vince

2017-10-01

Heat transfers are involved in many phenomena such as friction, tensile stress, shear stress and material rupture. Among the challenges encountered during the characterization of such thermal patterns is the need for both high spatial and temporal resolution. Infrared imaging provides information about surface temperature that can be attributed to the stress response of the material and breaking of chemical bounds. In order to illustrate this concept, tensile and shear tests were carried out on steel, aluminum and carbon fiber composite materials and monitored using high-speed (Telops FASTM2K) and high-definition (Telops HD-IR) infrared imaging. Results from split-Hopkinson experiments carried out on a polymer material at high strain-rate are also presented. The results illustrate how high-speed and high-definition infrared imaging in the midwave infrared (MWIR, 3 - 5 μm) spectral range can provide detailed information about the thermal properties of materials undergoing mechanical testing.

High speed electronic imaging application in aeroballistic research

International Nuclear Information System (INIS)

Brown, R.R.; Parker, J.R.

1984-01-01

Physical and temporal restrictions imposed by modern aeroballistics have pushed imaging technology to the point where special photoconductive surfaces and high-speed support electronics are dictated. Specifications for these devices can be formulated by a methodical analysis of critical parameters and how they interact. In terms of system theory, system transfer functions and state equations can be used in optimal coupling of devices to maximize system performance. Application of these methods to electronic imaging at the Eglin Aeroballistics Research Facility is described in this report. 7 references, 14 figures, 1 table

Magnetic suspension and guidance of high speed vehicles. Final report

Energy Technology Data Exchange (ETDEWEB)

Alston, I A; Clark, J M; Hayden, J T

1972-12-01

Technical and economical assessments of magnetic suspensions for high speed vehicles and transport systems are reported. In these suspensions the suspending magnet takes the form of a powerful superconducting electromagnet that induces currents while it moves over conducting sheets or loops. A number of vehicle track designs are evaluated for operating cost effectiveness. It is shown that propulsion systems using power collected from the track are more expensive than those using power generated onboard the vehicle, and that the conducting sheet suspension is slightly more expensive than the null flux suspension.

Automated High-Speed Video Detection of Small-Scale Explosives Testing

Science.gov (United States)

Ford, Robert; Guymon, Clint

2013-06-01

Small-scale explosives sensitivity test data is used to evaluate hazards of processing, handling, transportation, and storage of energetic materials. Accurate test data is critical to implementation of engineering and administrative controls for personnel safety and asset protection. Operator mischaracterization of reactions during testing contributes to either excessive or inadequate safety protocols. Use of equipment and associated algorithms to aid the operator in reaction determination can significantly reduce operator error. Safety Management Services, Inc. has developed an algorithm to evaluate high-speed video images of sparks from an ESD (Electrostatic Discharge) machine to automatically determine whether or not a reaction has taken place. The algorithm with the high-speed camera is termed GoDetect (patent pending). An operator assisted version for friction and impact testing has also been developed where software is used to quickly process and store video of sensitivity testing. We have used this method for sensitivity testing with multiple pieces of equipment. We present the fundamentals of GoDetect and compare it to other methods used for reaction detection.

Accurate prediction of complex free surface flow around a high speed craft using a single-phase level set method

Science.gov (United States)

Broglia, Riccardo; Durante, Danilo

2017-11-01

This paper focuses on the analysis of a challenging free surface flow problem involving a surface vessel moving at high speeds, or planing. The investigation is performed using a general purpose high Reynolds free surface solver developed at CNR-INSEAN. The methodology is based on a second order finite volume discretization of the unsteady Reynolds-averaged Navier-Stokes equations (Di Mascio et al. in A second order Godunov—type scheme for naval hydrodynamics, Kluwer Academic/Plenum Publishers, Dordrecht, pp 253-261, 2001; Proceedings of 16th international offshore and polar engineering conference, San Francisco, CA, USA, 2006; J Mar Sci Technol 14:19-29, 2009); air/water interface dynamics is accurately modeled by a non standard level set approach (Di Mascio et al. in Comput Fluids 36(5):868-886, 2007a), known as the single-phase level set method. In this algorithm the governing equations are solved only in the water phase, whereas the numerical domain in the air phase is used for a suitable extension of the fluid dynamic variables. The level set function is used to track the free surface evolution; dynamic boundary conditions are enforced directly on the interface. This approach allows to accurately predict the evolution of the free surface even in the presence of violent breaking waves phenomena, maintaining the interface sharp, without any need to smear out the fluid properties across the two phases. This paper is aimed at the prediction of the complex free-surface flow field generated by a deep-V planing boat at medium and high Froude numbers (from 0.6 up to 1.2). In the present work, the planing hull is treated as a two-degree-of-freedom rigid object. Flow field is characterized by the presence of thin water sheets, several energetic breaking waves and plungings. The computational results include convergence of the trim angle, sinkage and resistance under grid refinement; high-quality experimental data are used for the purposes of validation, allowing to

Ultra-high surface speed for metal removal, artillery shell

Science.gov (United States)

Pugh, R. F.; Walsh, M. R.; Pohl, R. F.

1981-07-01

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

Surface modification of bisphenol A polycarbonate material by ultraviolet Nd:YVO4 laser high-speed microprocessing technology

International Nuclear Information System (INIS)

Liu, Jianguo; Wang, Suhuan; Lv, Ming; Zeng, Xiaoyan

2014-01-01

In this paper, a low-cost and high-efficiency microprocessing modification technology for the surface of bisphenol A polycarbonate (BAPC) material was achieved (in particular, from hydrophilicity to hydrophobicity) at high laser scanning speeds (600–1000 mm s  − 1 ) and using an all-solid state, Q-switched, high-average power and nanosecond pulse Nd:YVO 4 laser (355 nm wavelength). During the modification, it was found that the laser fluence and pulse width were the two main parameters affecting the modification effect. Moreover, the modification had a significant effect on the water contact angle, wetting behavior, microstructure, average roughness and chemical composition of the surface. When the laser fluences applied were low (i.e., less than the so-called critical fluence of the UV laser modification of the BAPC material), the water contact angle was found to be a little less than the original, the hydrophilicity was slightly improved, the relative content of the oxygen-containing groups (e.g. O–C and COO  −  ) increased, the microstructure and average roughness only had a very slight change, and the wetting behavior complied with the Wenzel regime. On the other hand, when the laser fluences applied were high, the water contact angle significantly increased, the hydrophilicity markedly decreased and the relative content of the oxygen-containing groups also increased. Here, a porous microstructure with periodical v-type grooves was generated and the average roughness had an obvious increase. In this case, the wetting behavior could be explained by the Cassie-Baxter regime, i.e., the microstructure and average roughness change played a deciding role. The reason for this might be that different laser parameters result in different material deformation and removal processes, thereby resulting in different surface chemical compositions, microstructures, roughnesses and wetting properties. (paper)

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process

OpenAIRE

Dhandapani, N. V.; Thangarasu, V. S.; Sureshkannan, G.

2015-01-01

This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the...

PENGEOM-A general-purpose geometry package for Monte Carlo simulation of radiation transport in material systems defined by quadric surfaces

Science.gov (United States)

Almansa, Julio; Salvat-Pujol, Francesc; Díaz-Londoño, Gloria; Carnicer, Artur; Lallena, Antonio M.; Salvat, Francesc

2016-02-01

The Fortran subroutine package PENGEOM provides a complete set of tools to handle quadric geometries in Monte Carlo simulations of radiation transport. The material structure where radiation propagates is assumed to consist of homogeneous bodies limited by quadric surfaces. The PENGEOM subroutines (a subset of the PENELOPE code) track particles through the material structure, independently of the details of the physics models adopted to describe the interactions. Although these subroutines are designed for detailed simulations of photon and electron transport, where all individual interactions are simulated sequentially, they can also be used in mixed (class II) schemes for simulating the transport of high-energy charged particles, where the effect of soft interactions is described by the random-hinge method. The definition of the geometry and the details of the tracking algorithm are tailored to optimize simulation speed. The use of fuzzy quadric surfaces minimizes the impact of round-off errors. The provided software includes a Java graphical user interface for editing and debugging the geometry definition file and for visualizing the material structure. Images of the structure are generated by using the tracking subroutines and, hence, they describe the geometry actually passed to the simulation code.

The variation in visibility and its relationship with surface wind speed in China from 1960 to 2009

Science.gov (United States)

Sun, Tianze; Che, Huizheng; Wu, Jian; Wang, Hong; Wang, Yaqiang; Zhang, Xiaoye

2018-01-01

This study used daily visibility and surface wind speed observational data over the 50-year period from 1960 to 2009, from 464 national meteorological stations in China, to examine the relationship between these two variables. Specifically, using the statistical methods of empirical orthogonal function (EOF) analysis and wavelet analysis, the data were processed into anomaly data to study their spatial and temporal distributions and the characteristics of each pattern's periodicity after EOF analysis of the whole country's visibility and surface wind speed. Correlation analysis and composite analysis were then used to elucidate the relationship between the two variables on different time scales. The results showed a gradual reduction in visibility nationally, with the nine-point moving mean implying decadal variability of the visibility with a downward trend. However, an irregular oscillation was found for the inter-annual variability of visibility. For the anomaly series of visibility during the 50-year period, a long-period oscillation of around 32 years was apparent. Up until the 1990s, there was an approximate 16-year medium-term oscillation period, whereas, after the 1990s, an approximate 8-year oscillation period was generated. In terms of high correlation between the two variables, for the decadal variability, the changes in visibility and surface wind speed at this time scale were almost in agreement. Meanwhile, with respect to the serious pollution in the Yangtze River Delta Economic Zone, the correlation between the two variables was reasonably high, suggesting that surface wind had a significant influence on the scattering of aerosol particles. However, in the Sichuan Basin, the correlation was relatively low, possibly on account of its landscape limiting the variation of wind speed.

High-speed detection of DNA translocation in nanopipettes

Science.gov (United States)

Fraccari, Raquel L.; Ciccarella, Pietro; Bahrami, Azadeh; Carminati, Marco; Ferrari, Giorgio; Albrecht, Tim

2016-03-01

We present a high-speed electrical detection scheme based on a custom-designed CMOS amplifier which allows the analysis of DNA translocation in glass nanopipettes on a microsecond timescale. Translocation of different DNA lengths in KCl electrolyte provides a scaling factor of the DNA translocation time equal to p = 1.22, which is different from values observed previously with nanopipettes in LiCl electrolyte or with nanopores. Based on a theoretical model involving electrophoresis, hydrodynamics and surface friction, we show that the experimentally observed range of p-values may be the result of, or at least be affected by DNA adsorption and friction between the DNA and the substrate surface.We present a high-speed electrical detection scheme based on a custom-designed CMOS amplifier which allows the analysis of DNA translocation in glass nanopipettes on a microsecond timescale. Translocation of different DNA lengths in KCl electrolyte provides a scaling factor of the DNA translocation time equal to p = 1.22, which is different from values observed previously with nanopipettes in LiCl electrolyte or with nanopores. Based on a theoretical model involving electrophoresis, hydrodynamics and surface friction, we show that the experimentally observed range of p-values may be the result of, or at least be affected by DNA adsorption and friction between the DNA and the substrate surface. Electronic supplementary information (ESI) available: Gel electrophoresis confirming lengths and purity of DNA samples, comparison between Axopatch 200B and custom-built setup, comprehensive low-noise amplifier characterization, representative I-V curves of nanopipettes used, typical scatter plots of τ vs. peak amplitude for the four LDNA's used, table of most probable τ values, a comparison between different fitting models for the DNA translocation time distribution, further details on the stochastic numerical simulation of the scaling statistics and the derivation of the extended

Unstructured Grid Euler Method Assessment for Aerodynamics Performance Prediction of the Complete TCA Configuration at Supersonic Cruise Speed

Science.gov (United States)

Ghaffari, Farhad

1999-01-01

Unstructured grid Euler computations, performed at supersonic cruise speed, are presented for a proposed high speed civil transport configuration, designated as the Technology Concept Airplane (TCA) within the High Speed Research (HSR) Program. The numerical results are obtained for the complete TCA cruise configuration which includes the wing, fuselage, empennage, diverters, and flow through nacelles at Mach 2.4 for a range of angles-of-attack and sideslip. The computed surface and off-surface flow characteristics are analyzed and the pressure coefficient contours on the wing lower surface are shown to correlate reasonably well with the available pressure sensitive paint results, particularly, for the complex shock wave structures around the nacelles. The predicted longitudinal and lateral/directional performance characteristics are shown to correlate very well with the measured data across the examined range of angles-of-attack and sideslip. The results from the present effort have been documented into a NASA Controlled-Distribution report which is being presently reviewed for publication.

Predicting of bead undercut defects in high-speed gas metal arc welding (GMAW)

Institute of Scientific and Technical Information of China (English)

Wen-jing XU; Chuan-song WU; De-gang ZOU

2008-01-01

In the gas metal arc welding (GMAW) process, when the welding speed reaches a certain threshold, there will be an onset of weld bead undercut defects which limit the further increase of the welding speed. Establishing a mathematical model for high-speed GMAW to predict the tendency of bead undercuts is of great significance to pre-vent such defects. Under the action of various forces, the transferred metal from filler wire to the weld pool, and the geometry and dimension of the pool itself decide if the bead undercut occurs or not. The previous model simpli-fied the pool shape too much. In this paper, based on the actual weld pool geometry and dimension calculated from a numerical model, a hydrostatic model for liquid metal surface is used to study the onset of bead undercut defects in the high-speed welding process and the effects of dif-ferent welding parameters on the bead undercut tendency.

AN ANALYSIS OF SPATIAL EQUITY CONCERNING INVESTMENTS IN HIGH-SPEED RAIL SYSTEMS: THE CASE STUDY OF ITALY

Directory of Open Access Journals (Sweden)

Francesca PAGLIARA

2016-09-01

Full Text Available It is recognised in the literature that spatial accessibility is a measure of spatial equity and can be represented by the ease of travelling from an origin to a given destination via a given mode or set of transport modes. Although urban areas can benefit from improvements in accessibility when a new high-speed rail line is built, equity issues may arise. This manuscript describes a methodology for evaluating equity impacts due to an extension of the High Speed Rail network in Italy. A joint Revealed/Stated Preference survey has been carried out, collecting socioeconomic and travel data. Specifically, nine hypothetical scenarios have been submitted to Italian users aiming at understanding the motivations for not choosing the High Speed Rail as an alternative. The main outcome is that the access/egress travel costs connected with the High Speed Rail have a strong impact on spatial equity. The main policy implications of this study are that investors in high-speed rail should not only take into account the economic benefits brought by them, but also the spatial imbalance that these systems can bring.

Analyzing the Potential for High-speed Rail as Part of the Multimodal Transportation System in the United States' Midwest Corridor

Directory of Open Access Journals (Sweden)

Jeffrey C. Peters

2014-06-01

Full Text Available With increasing demand and rising fuel costs, both travel time and cost of current intercity passenger transportation modes are becoming increasingly relevant. Around the world, highspeed rail (HSR is seen as a way to alleviate demand on highways and at airports. Ridership is the critical element in determining the viability of a large capital, long-term transportation investment. This paper provides a systematic, consistent methodology for analyzing systemwide modal ridership with and without a proposed HSR network and analyzes the potential for highspeed rail as part of the existing multimodal transportation system in a region in terms of ridership. Considerations of capital investment (e.g., network design and HSR speed, along with exogenous demographic, technological, economic, and policy trends in the long-term, are used to project ridership over time. This study represents an important step toward a consistent, comprehensive economic analysis of HSR in the United States.

Wind speed and direction shears with associated vertical motion during strong surface winds

Science.gov (United States)

Alexander, M. B.; Camp, D. W.

1984-01-01

Strong surface winds recorded at the NASA 150-Meter Ground Winds Tower facility at Kennedy Space Center, Florida, are analyzed to present occurrences representative of wind shear and vertical motion known to be hazardous to the ascent and descent of conventional aircraft and the Space Shuttle. Graphical (percentage frequency distributions) and mathematical (maximum, mean, standard deviation) descriptions of wind speed and direction shears and associated updrafts and downdrafts are included as functions of six vertical layers and one horizontal distance for twenty 5-second intervals of parameters sampled simultaneously at the rate of ten per second during a period of high surface winds.

Design and Analysis of Transport Protocols for Reliable High-Speed Communications

NARCIS (Netherlands)

Oláh, A.

1997-01-01

The design and analysis of transport protocols for reliable communications constitutes the topic of this dissertation. These transport protocols guarantee the sequenced and complete delivery of user data over networks which may lose, duplicate and reorder packets. Reliable transport services are

Establishing Relationship between Process Parameters and Temperature during High Speed End Milling of Soda Lime Glass

Science.gov (United States)

Nasima Bagum, Mst.; Konneh, Mohamed; Yeakub Ali, Mohammad

2018-01-01

In glass machining crack free surface is required in biomedical and optical industry. Ductile mode machining allows materials removal from brittle materials in a ductile manner rather than by brittle fracture. Although end milling is a versatile process, it has not been applied frequently for machining soda lime glass. Soda lime glass is a strain rate and temperature sensitive material; especially around glass transition temperature Tg, ductility increased and strength decreased. Hence, it is envisaged that the generated temperature by high-speed end milling (HSEM) could be brought close to the glass transition temperature, which promote ductile machining. In this research, the objective is to investigate the effect of high speed machining parameters on generated temperature. The cutting parameters were optimized to generate temperature around glass transition temperature of soda lime using response surface methodology (RSM). Result showed that the most influencing process parameter is feed rate followed by spindle speed and depth of cut to generate temperature. Confirmation test showed that combination of spindle speed 30,173 rpm, feed rate 13.2 mm/min and depth of cut 37.68 µm generate 635°C, hence ductile chip removal with machined surface Ra 0.358 µm was possible to achieve.

Assessment of the Effects of High-Speed Aircraft in the Stratosphere: 1998

Science.gov (United States)

Kawa, S. Randolph; Anderson, James G.; Baughcum, Steven L.; Brock, Charles A.; Brune, William H.; Cohen, Ronald C.; Kinnison, Douglas E.; Newman, Paul A.; Rodriguez, Jose M.; Stolarski, Richard S.;

High speed VLSI neural network for high energy physics

NARCIS (Netherlands)

Masa, P.; Masa, P.; Hoen, K.; Hoen, Klaas; Wallinga, Hans

1994-01-01

A CMOS neural network IC is discussed which was designed for very high speed applications. The parallel architecture, analog computing and digital weight storage provides unprecedented computing speed combined with ease of use. The circuit classifies up to 70 dimensional vectors within 20

Improving the Efficiency of a High Speed Catamaran Through the Replacement of the Propulsion System

Directory of Open Access Journals (Sweden)

German de Melo Rodriguez

2015-12-01

Full Text Available The high speed vessels are primarily designed for short distances services as public transport of passengers and vehicles. The range of high speed, according to the Code of high-speed vessels begins at 20 knots, which depends on the cruise speed you desire for your vessel; you will have to use the most appropriate type of propellant. In general, in the past 20 years, they have been building high-speed vessels with speeds above 33 knots, which meant installing water jet propellants coupled to powerful engines and therefore of high consumption of fuel, increasing operating costs and causing increased air pollution. Although the prices of fuel have been reduced to half, due to the sharp fall in oil prices, the consumption of fuel and the air pollution remains high at these speeds and powers used, in addition to that the reduction of the time spent on each trip is not excessive, mainly in short routes that are less than an hour . This article is about adapting a ship of high-speed service, with a maximum speed in tests of 34 knots and to reduce its operating costs (fuel, maintenance, etc. and make it economically viable; before the transformation, this vessel was operating with a service speed of 22 knots, and with a consumption per mile of 135 litters of MGO. The transformation process has consisted by: – Replacement of the two original water jet with four shaft lines with fix pitch propeller. – Replacement of the two original main engines (2 x 6500 kW = 13000 kW by four engines (4 x 1380kW = 5.520 kW. – Changing the underwater hull shape to fit the new propellers and maximize its efficiency. – Relocation of auxiliary engines, to achieve the most efficient trim. – Installation of two lateral propellers to improve maneuverability and shorten the total time of journey. After the reform and the return to service of the vessel with a service speed of over 22 knots, it has been verified that the consumption per mile is of 45 litters MGO

Turbulent transport across invariant canonical flux surfaces

International Nuclear Information System (INIS)

Hollenberg, J.B.; Callen, J.D.

1994-07-01

Net transport due to a combination of Coulomb collisions and turbulence effects in a plasma is investigated using a fluid moment description that allows for kinetic and nonlinear effects via closure relations. The model considered allows for ''ideal'' turbulent fluctuations that distort but preserve the topology of species-dependent canonical flux surfaces ψ number-sign,s triple-bond ∫ dF · B number-sign,s triple-bond ∇ x [A + (m s /q s )u s ] in which u s is the flow velocity of the fluid species. Equations for the net transport relative to these surfaces due to ''nonideal'' dissipative processes are found for the total number of particles and total entropy enclosed by a moving canonical flux surface. The corresponding particle transport flux is calculated using a toroidal axisymmetry approximation of the ideal surfaces. The resulting Lagrangian transport flux includes classical, neoclassical-like, and anomalous contributions and shows for the first time how these various contributions should be summed to obtain the total particle transport flux

Evaluation of Hole Quality in Hardened Steel with High-Speed Drilling Using Different Cooling Systems

Directory of Open Access Journals (Sweden)

Lincoln Cardoso Brandão

2011-01-01

Full Text Available This work evaluates the hole quality on AISI H13 hardened steel using high-speed drilling. Specimens were machined with new and worn out drills with 8.6 mm diameter and (TiAlN coating. Two levels of cutting speed and three levels of cooling/lubrication systems (flooded, minimum lubrication quantity, and dry were used. The hole quality is evaluated on surface roughness (Ra parameter, diameter error, circularity, and cylindricity error. A statistical analysis of the results shows that the cooling/lubrication system significantly affects the hole quality for all measured variables. This analysis indicates that dry machining produces the worst results. Higher cutting speeds not only prove beneficial to diameter error and circularity errors, but also show no significant difference on surface roughness and cylindricity errors. The effects of the interaction between the cooling/lubrication systems, tool wear, and cutting speed indicate that only cylindricity error is influenced. Thus, the conclusion is that the best hole quality is produced with a higher cutting speed using flooded or minimum lubrication quantity independent of drill wear.

Enhancing Plasma Surface Modification using high Intensity and high Power Ultrasonic Acoustic Waves

DEFF Research Database (Denmark)

2010-01-01

high intensity and high power acoustic waves (102) by at least one ultrasonic high intensity and high power acoustic wave generator (101 ), wherein the ultrasonic acoustic waves are directed to propagate towards said surface (314) of the object (100) so that a laminar boundary layer (313) of a gas...... or a mixture of gases (500) flow in contact with said solid object (100) is thinned or destructed for at least a part of said surface (314). In this way, the plasma can more efficiently access and influence the surface of the solid object to be treated by the plasma, which speeds the process time up...

The dynamic behaviour of rail vehicles operating at high speeds for manriding in British coal mines

Energy Technology Data Exchange (ETDEWEB)

Manen, P. van

1984-01-01

The behaviour of trains used at high speeds for transporting men along mine railways is examined using a number of mathematical models. These models predict the responses of different rail vehicles to typical irregularities in the track, and are used to examine the guidance, the ride, and the likelihood of derailment of the main classes of manriding trains used in British coal mines. The outcome of the modelling compares favourably with the results of tests carried out on actual vehicles. The investigation has shown that the safe speed at which trains may operate is ultimately restricted by the condition of the track, but changes in the design of the vehicles can lead to an improved performance. The use of conventional wheelsets, for example, can reduce flange wear significantly and so allow higher speeds to be reached. Guidelines for the design of vehicles intended for high speed use are included in this thesis. (36 refs.)

A High-Speed Design of Montgomery Multiplier

Science.gov (United States)

Fan, Yibo; Ikenaga, Takeshi; Goto, Satoshi

With the increase of key length used in public cryptographic algorithms such as RSA and ECC, the speed of Montgomery multiplication becomes a bottleneck. This paper proposes a high speed design of Montgomery multiplier. Firstly, a modified scalable high-radix Montgomery algorithm is proposed to reduce critical path. Secondly, a high-radix clock-saving dataflow is proposed to support high-radix operation and one clock cycle delay in dataflow. Finally, a hardware-reused architecture is proposed to reduce the hardware cost and a parallel radix-16 design of data path is proposed to accelerate the speed. By using HHNEC 0.25μm standard cell library, the implementation results show that the total cost of Montgomery multiplier is 130 KGates, the clock frequency is 180MHz and the throughput of 1024-bit RSA encryption is 352kbps. This design is suitable to be used in high speed RSA or ECC encryption/decryption. As a scalable design, it supports any key-length encryption/decryption up to the size of on-chip memory.

Analysis of SCTP and TCP based communication in high-speed clusters

International Nuclear Information System (INIS)

Kozlovszky, M.; Berceli, T.; Kutor, L.

2006-01-01

Performance and financial constraints are pushing modern DAQs (Data Acquisition Systems) to use distributed cluster environments instead of monolith one-box systems. Inside clusters application communication layers should support outstanding high performance requirements. We are currently investigating different network protocols that could meet the requirements of high speed/low latency peer-to-peer communication within DAQ clusters. We have carried out various performance measurements with TCP and SCTP over Fast and Gigabit Ethernet. We are focusing on Ethernet Technologies, because this transport medium is broad deployed, cost efficient and it has much better cost/throughput ratio than other available communication alternatives (e.g.: Myrinet, Infiniband). During this study, a protocol performance measurement application with different peer transport components has been developed. In the first part of the paper, we give a short comparison of the two protocols (SCTP and TCP), and an introduction of the transport layer structure developed. Later on we discuss the performance results of single/multi-stream peer-to-peer communication, give overview about application code transition possibilities from application developer point of view between the two protocols, and draw conclusions about usability

High-speed and high-fidelity system and method for collecting network traffic

Science.gov (United States)

Weigle, Eric H [Los Alamos, NM

2010-08-24

A system is provided for the high-speed and high-fidelity collection of network traffic. The system can collect traffic at gigabit-per-second (Gbps) speeds, scale to terabit-per-second (Tbps) speeds, and support additional functions such as real-time network intrusion detection. The present system uses a dedicated operating system for traffic collection to maximize efficiency, scalability, and performance. A scalable infrastructure and apparatus for the present system is provided by splitting the work performed on one host onto multiple hosts. The present system simultaneously addresses the issues of scalability, performance, cost, and adaptability with respect to network monitoring, collection, and other network tasks. In addition to high-speed and high-fidelity network collection, the present system provides a flexible infrastructure to perform virtually any function at high speeds such as real-time network intrusion detection and wide-area network emulation for research purposes.

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

Science.gov (United States)

2013-05-16

... federal High-Speed Intercity Passenger Rail (HSIPR) program and includes the development of a Passenger.... Background The Atlanta-Charlotte Corridor faces mobility challenges. Transportation demand and travel growth... travel time and reliability, provide another reliable mode choice, create jobs, reduce dependence on...

Pose Measurement Method and Experiments for High-Speed Rolling Targets in a Wind Tunnel

Directory of Open Access Journals (Sweden)

Zhenyuan Jia

2014-12-01

Full Text Available High-precision wind tunnel simulation tests play an important role in aircraft design and manufacture. In this study, a high-speed pose vision measurement method is proposed for high-speed and rolling targets in a supersonic wind tunnel. To obtain images with high signal-to-noise ratio and avoid impacts on the aerodynamic shape of the rolling targets, a high-speed image acquisition method based on ultrathin retro-reflection markers is presented. Since markers are small-sized and some of them may be lost when the target is rolling, a novel markers layout with which markers are distributed evenly on the surface is proposed based on a spatial coding method to achieve highly accurate pose information. Additionally, a pose acquisition is carried out according to the mentioned markers layout after removing mismatching points by Case Deletion Diagnostics. Finally, experiments on measuring the pose parameters of high-speed targets in the laboratory and in a supersonic wind tunnel are conducted to verify the feasibility and effectiveness of the proposed method. Experimental results indicate that the position measurement precision is less than 0.16 mm, the pitching and yaw angle precision less than 0.132° and the roll angle precision 0.712°.

Pose measurement method and experiments for high-speed rolling targets in a wind tunnel.

Science.gov (United States)

Jia, Zhenyuan; Ma, Xin; Liu, Wei; Lu, Wenbo; Li, Xiao; Chen, Ling; Wang, Zhengqu; Cui, Xiaochun

2014-12-12

High-precision wind tunnel simulation tests play an important role in aircraft design and manufacture. In this study, a high-speed pose vision measurement method is proposed for high-speed and rolling targets in a supersonic wind tunnel. To obtain images with high signal-to-noise ratio and avoid impacts on the aerodynamic shape of the rolling targets, a high-speed image acquisition method based on ultrathin retro-reflection markers is presented. Since markers are small-sized and some of them may be lost when the target is rolling, a novel markers layout with which markers are distributed evenly on the surface is proposed based on a spatial coding method to achieve highly accurate pose information. Additionally, a pose acquisition is carried out according to the mentioned markers layout after removing mismatching points by Case Deletion Diagnostics. Finally, experiments on measuring the pose parameters of high-speed targets in the laboratory and in a supersonic wind tunnel are conducted to verify the feasibility and effectiveness of the proposed method. Experimental results indicate that the position measurement precision is less than 0.16 mm, the pitching and yaw angle precision less than 0.132° and the roll angle precision 0.712°.

Role of molecular charge in nucleocytoplasmic transport.

Directory of Open Access Journals (Sweden)

Alexander Goryaynov

Full Text Available Transport of genetic materials and proteins between the nucleus and cytoplasm of eukaryotic cells is mediated by nuclear pore complexes (NPCs. A selective barrier formed by phenylalanine-glycine (FG nucleoporins (Nups with net positive charges in the NPC allows for passive diffusion of signal-independent small molecules and transport-receptor facilitated translocation of signal-dependent cargo molecules. Recently, negative surface charge was postulated to be another essential criterion for selective passage through the NPC. However, the charge-driven mechanism in determining the transport kinetics and spatial transport route for either passive diffusion or facilitated translocation remains obscure. Here we employed high-speed single-molecule fluorescence microscopy with an unprecedented spatiotemporal resolution of 9 nm and 400 µs to uncover these mechanistic fundamentals for nuclear transport of charged substrates through native NPCs. We found that electrostatic interaction between negative surface charges on transiting molecules and the positively charged FG Nups, although enhancing their probability of binding to the NPC, never plays a dominant role in determining their nuclear transport mode or spatial transport route. A 3D reconstruction of transport routes revealed that small signal-dependent endogenous cargo protein constructs with high positive surface charges that are destined to the nucleus, rather than repelled from the NPC as suggested in previous models, passively diffused through an axial central channel of the NPC in the absence of transport receptors. Finally, we postulated a comprehensive map of interactions between transiting molecules and FG Nups during nucleocytoplasmic transport by combining the effects of molecular size, signal and surface charge.

TECHNICAL NOTE: High-speed grinding using thin abrasive disks for microcomponents

Science.gov (United States)

Yeo, S. H.; Balon, S. A. P.

2002-01-01

This paper introduces the development of a high-speed grinding device for cylindrical grinding of microcomponents made of hard and brittle materials. The study made use of an ultraprecision diamond turning machine tool as a basic platform. The novelty of the device is based on the high-speed air bearing spindle with a thin grinding wheel, similar to the dicing technology for silicon wafer fabrication. The spindle attachment is inclined at an angle to the main spindle which holds the precision fixture mechanism via the vacuum chuck. Experiments have been conducted to verify the design and implementation of the grinding methodology. A feature size as small as 31 μm in diameter and average surface roughness of 98 nm were obtained in the experimental work. It is found that the work done is capable of manufacturing miniature components, such as microcylindrical stepped shafts.

High-Speed Research: 1994 Sonic Boom Workshop. Configuration, Design, Analysis and Testing

Science.gov (United States)

McCurdy, David A. (Editor)

1999-01-01

The third High-Speed Research Sonic Boom Workshop was held at NASA Langley Research Center on June 1-3, 1994. The purpose of this workshop was to provide a forum for Government, industry, and university participants to present and discuss progress in their research. The workshop was organized into sessions dealing with atmospheric propagation; acceptability studies; and configuration design, and testing. Attendance at the workshop was by invitation only. The workshop proceedings include papers on design, analysis, and testing of low-boom high-speed civil transport configurations and experimental techniques for measuring sonic booms. Significant progress is noted in these areas in the time since the previous workshop a year earlier. The papers include preliminary results of sonic boom wind tunnel tests conducted during 1993 and 1994 on several low-boom designs. Results of a mission performance analysis of all low-boom designs are also included. Two experimental methods for measuring near-field signatures of airplanes in flight are reported.

Study on leakage rates of high temperature water from wet-type transport casks for spent fuel. Pt. 2. Leakage rates from a scratch on O-ring surface and narrow wires adhering to O-ring surface

International Nuclear Information System (INIS)

Asano, R.; Aritomi, M.; Sudi, A.; Kohketsu, Y.

1997-01-01

A programme for enhancement of fuel burnup has been promoted in Japan as part of the sophisticated programme for light water reactors to reduce the fuel cost and the amount of spent fuel. As part of this fuel programme, a new wet-type transport cask has been developed to transport the high burnup fuels efficiently. The purpose of this work is to clarify the margin of safety in the evaluation of the release rate of radioactive materials from the wet-type transport cask into the environment and to establish a practical evaluation method for leakage rates on leak behaviour of high temperature water from the casks. In this paper, leakage rates of water under high pressures and at high temperatures are investigated from two kinds of leak path model. One is a disc with a scratch on the surface which simulates a defect on the seal surface of the O-ring flange and the other is narrow stainless steel wires installed on the O-ring surface which simulates hair adhering to the O-ring surface. From the results, an evaluation method for the leakage rate of water under high pressure and at high temperature from a non-circular leak path and multiple leak paths is proposed. (author)

A NEW METHOD TO DETECT REGIONS ENDANGERED BY HIGH WIND SPEEDS

Directory of Open Access Journals (Sweden)

P. Fischer

2016-06-01

Full Text Available In this study we evaluate whether the methodology of Boosted Regression Trees (BRT suits for accurately predicting maximum wind speeds. As predictors a broad set of parameters derived from a Digital Elevation Model (DEM acquired within the Shuttle Radar Topography Mission (SRTM is used. The derived parameters describe the surface by means of quantities (e.g. slope, aspect and quality (landform classification. Furthermore land cover data from the CORINE dataset is added. The response variable is maximum wind speed, measurements are provided by a network of weather stations. The area of interest is Switzerland, a country which suits perfectly for this study because of its highly dynamic orography and various landforms.

Potential scenarios of concern for high speed rail operations

Science.gov (United States)

2011-03-16

Currently, multiple operating authorities are proposing the : introduction of high-speed rail service in the United States. : While high-speed rail service shares a number of basic : principles with conventional-speed rail service, the operational : ...

Online Dynamic Balance Technology for High Speed Spindle Based on Gain Parameter Adaption and Scheduling Control

Directory of Open Access Journals (Sweden)

Shihai Zhang

2018-06-01

Full Text Available Unbalance vibration is one of the main vibration forms of a high speed machine tool spindle. The overlarge unbalance vibration will have some adverse effects on the working life of the spindle system and the surface quality of the work-piece. In order to reduce the unbalance of a high speed spindle system, a pneumatic online dynamic balance device and its control system are presented in the paper. To improve the balance accuracy and adaptation of the balance system, the gain parameter adaption and scheduling control method are proposed first, and then the different balance effects of the influence coefficient method and the gain scheduling control method are compared through many dynamic balance experiments of the high speed spindle. The experimental results indicate that the gain parameters can be changed timely according to the transformation of the speed and kinetic parameters of the spindle system. The balance accuracy can be improved for a high speed spindle with time-varying characteristics, based on the adaptive gain scheduling control method.

High-speed atomic force microscopy combined with inverted optical microscopy for studying cellular events.

Science.gov (United States)

Suzuki, Yuki; Sakai, Nobuaki; Yoshida, Aiko; Uekusa, Yoshitsugu; Yagi, Akira; Imaoka, Yuka; Ito, Shuichi; Karaki, Koichi; Takeyasu, Kunio

2013-01-01

A hybrid atomic force microscopy (AFM)-optical fluorescence microscopy is a powerful tool for investigating cellular morphologies and events. However, the slow data acquisition rates of the conventional AFM unit of the hybrid system limit the visualization of structural changes during cellular events. Therefore, high-speed AFM units equipped with an optical/fluorescence detection device have been a long-standing wish. Here we describe the implementation of high-speed AFM coupled with an optical fluorescence microscope. This was accomplished by developing a tip-scanning system, instead of a sample-scanning system, which operates on an inverted optical microscope. This novel device enabled the acquisition of high-speed AFM images of morphological changes in individual cells. Using this instrument, we conducted structural studies of living HeLa and 3T3 fibroblast cell surfaces. The improved time resolution allowed us to image dynamic cellular events.

Numerical study on wake characteristics of high-speed trains

Science.gov (United States)

Yao, Shuan-Bao; Sun, Zhen-Xu; Guo, Di-Long; Chen, Da-Wei; Yang, Guo-Wei

2013-12-01

Intensive turbulence exists in the wakes of high speed trains, and the aerodynamic performance of the trailing car could deteriorate rapidly due to complicated features of the vortices in the wake zone. As a result, the safety and amenity of high speed trains would face a great challenge. This paper considers mainly the mechanism of vortex formation and evolution in the train flow field. A real CRH2 model is studied, with a leading car, a middle car and a trailing car included. Different running speeds and cross wind conditions are considered, and the approaches of unsteady Reynold-averaged Navier-Stokes (URANS) and detached eddy simulation (DES) are utilized, respectively. Results reveal that DES has better capability of capturing small eddies compared to URANS. However, for large eddies, the effects of two approaches are almost the same. In conditions without cross winds, two large vortex streets stretch from the train nose and interact strongly with each other in the wake zone. With the reinforcement of the ground, a complicated wake vortex system generates and becomes strengthened as the running speed increases. However, the locations of flow separations on the train surface and the separation mechanism keep unchanged. In conditions with cross winds, three large vortices develop along the leeward side of the train, among which the weakest one has no obvious influence on the wake flow while the other two stretch to the tail of the train and combine with the helical vortices in the train wake. Thus, optimization of the aerodynamic performance of the trailing car should be aiming at reducing the intensity of the wake vortex system.

WIND SPEED AND ATMOSPHERIC STABILITY TRENDS FOR SELECTED UNITED STATES SURFACE STATIONS

Energy Technology Data Exchange (ETDEWEB)

Buckley, R; Allen H. Weber, A

2006-11-01

Recently it has been suggested that global warming and a decrease in mean wind speeds over most land masses are related. Decreases in near surface wind speeds have been reported by previous investigators looking at records with time spans of 15 to 30 years. This study focuses on United States (US) surface stations that have little or no location change since the late 1940s or the 1950s--a time range of up to 58 years. Data were selected from 62 stations (24 of which had not changed location) and separated into ten groups for analysis. The group's annual averages of temperature, wind speed, and percentage of Pasquill-Gifford (PG) stability categories were fitted with linear least squares regression lines. The results showed that the temperatures have increased for eight of the ten groups as expected. Wind speeds have decreased for nine of the ten groups. The mean slope of the wind speed trend lines for stations within the coterminous US was -0.77 m s{sup -1} per century. The percentage frequency of occurrence for the neutral (D) PG stability category decreased, while that for the unstable (B) and the stable (F) categories increased in almost all cases except for the group of stations located in Alaska.

High-Speed Non-Volatile Optical Memory: Achievements and Challenges

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Vadym Zayets

2017-01-01

Full Text Available We have proposed, fabricated, and studied a new design of a high-speed optical non-volatile memory. The recoding mechanism of the proposed memory utilizes a magnetization reversal of a nanomagnet by a spin-polarized photocurrent. It was shown experimentally that the operational speed of this memory may be extremely fast above 1 TBit/s. The challenges to realize both a high-speed recording and a high-speed reading are discussed. The memory is compact, integratable, and compatible with present semiconductor technology. If realized, it will advance data processing and computing technology towards a faster operation speed.

HIGH-RESOLUTION CALCULATION OF THE SOLAR GLOBAL CONVECTION WITH THE REDUCED SPEED OF SOUND TECHNIQUE. II. NEAR SURFACE SHEAR LAYER WITH THE ROTATION

Energy Technology Data Exchange (ETDEWEB)

Hotta, H.; Rempel, M. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO (United States); Yokoyama, T., E-mail: hotta@ucar.edu [Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2015-01-01

We present a high-resolution, highly stratified numerical simulation of rotating thermal convection in a spherical shell. Our aim is to study in detail the processes that can maintain a near surface shear layer (NSSL) as inferred from helioseismology. Using the reduced speed of sound technique, we can extend our global convection simulation to 0.99 R {sub ☉} and include, near the top of our domain, small-scale convection with short timescales that is only weakly influenced by rotation. We find the formation of an NSSL preferentially in high latitudes in the depth range of r = 0.95-0.975 R {sub ☉}. The maintenance mechanisms are summarized as follows. Convection under the weak influence of rotation leads to Reynolds stresses that transport angular momentum radially inward in all latitudes. This leads to the formation of a strong poleward-directed meridional flow and an NSSL, which is balanced in the meridional plane by forces resulting from the 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 correlation of turbulent velocities. The origin of the required correlations depends to some degree on latitude. In high latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 is induced in the NSSL by the poleward meridional flow whose amplitude increases with the radius, while a negative correlation is generated by the Coriolis force in bulk of the convection zone. In low latitudes, a positive correlation 〈v{sub r}{sup ′}v{sub θ}{sup ′}〉 results from rotationally aligned convection cells ({sup b}anana cells{sup )}. The force caused by these Reynolds stresses is in balance with the Coriolis force in the NSSL.

High speed laser tomography system

Science.gov (United States)

Samsonov, D.; Elsaesser, A.; Edwards, A.; Thomas, H. M.; Morfill, G. E.

2008-03-01

A high speed laser tomography system was developed capable of acquiring three-dimensional (3D) images of optically thin clouds of moving micron-sized particles. It operates by parallel-shifting an illuminating laser sheet with a pair of galvanometer-driven mirrors and synchronously recording two-dimensional (2D) images of thin slices of the imaged volume. The maximum scanning speed achieved was 120000slices/s, sequences of 24 volume scans (up to 256 slices each) have been obtained. The 2D slices were stacked to form 3D images of the volume, then the positions of the particles were identified and followed in the consecutive scans. The system was used to image a complex plasma with particles moving at speeds up to cm/s.

A Historical Review of High Speed Metal Forming

OpenAIRE

Zittel, G.

2010-01-01

This paper will present a Historical Review of High Speed Metal Forming beginning with the first thought of forming metal by using an electromagnetic impulse to today, whereby High Speed Metal Forming is an accepted production process. Although this paper will briefly cover the basic physics of the process, it will not dwell on it. It will rather show how the industrial acceptance of High Speed Metal Forming is tightly connected to the knowledge acquired from many applications studies. These ...

Control over Coating Structure during Electromagnetic Welding and Application of HighSpeed Steel Powder

Directory of Open Access Journals (Sweden)

L. M. Kozhuro

2004-01-01

Full Text Available The paper considers peculiar features concerning coating formation in the process of electromagnetic welding of high-speed steel powder. The paper reveals how to control coating structure that ensures the required operational properties of working surfaces of machine parts. 

High-frequency acoustic charge transport in GaAs nanowires

NARCIS (Netherlands)

Büyükköse, S.; Hernandez-Minguez, A.; Vratzov, B.; Somaschini, C.; Geelhaar, L.; Riechert, H.; van der Wiel, Wilfred Gerard; Santos, P.V.

2014-01-01

The oscillating piezoelectric fields accompanying surface acoustic waves are able to transport charge carriers in semiconductor heterostructures. Here, we demonstrate high-frequency (above 1 GHz) acoustic charge transport in GaAs-based nanowires deposited on a piezoelectric substrate. The short

Subsurface damage mechanism of high speed grinding process in single crystal silicon revealed by atomistic simulations

International Nuclear Information System (INIS)

Li, Jia; Fang, Qihong; Zhang, Liangchi; Liu, Youwen

2015-01-01

Highlights: • Molecular dynamic model of nanoscale high speed grinding of silicon workpiece has been established. • The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation during high speed grinding process are thoroughly investigated. • Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle. • The hydrostatic stress and von Mises stress by the established analytical model are studied subsurface damage mechanism during nanoscale grinding. - Abstract: Three-dimensional molecular dynamics (MD) simulations are performed to investigate the nanoscale grinding process of single crystal silicon using diamond tool. The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation are studied. We also establish an analytical model to calculate several important stress fields including hydrostatic stress and von Mises stress for studying subsurface damage mechanism, and obtain the dislocation density on the grinding subsurface. The results show that a higher grinding velocity in machining brittle material silicon causes a larger chip and a higher temperature, and reduces subsurface damage. However, when grinding velocity is above 180 m s −1 , subsurface damage thickness slightly increases because a higher grinding speed leads to the increase in grinding force and temperature, which accelerate dislocation nucleation and motion. Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle, that provides valuable reference for machining nanometer devices. The von Mises stress and the hydrostatic stress play an important role in the grinding process, and explain the subsurface damage though dislocation mechanism under high

In-process, non-destructive, dynamic testing of high-speed polymer composite rotors

Science.gov (United States)

Kuschmierz, Robert; Filippatos, Angelos; Günther, Philipp; Langkamp, Albert; Hufenbach, Werner; Czarske, Jürgen; Fischer, Andreas

2015-03-01

Polymer composite rotors are lightweight and offer great perspectives in high-speed applications such as turbo machinery. Currently, novel rotor structures and materials are investigated for the purpose of increasing machine efficiency and lifetime, as well as allowing for higher dynamic loads. However, due to the complexity of the composite materials an in-process measurement system is required. This allows for monitoring the evolution of damages under dynamic loads, for testing and predicting the structural integrity of composite rotors in process. In rotor design, it can be used for calibrating and improving models, simulating the dynamic behaviour of polymer composite rotors. The measurement system is to work non-invasive, offer micron uncertainty, as well as a high measurement rate of several tens of kHz. Furthermore, it must be applicable at high surface speeds and under technical vacuum. In order to fulfil these demands a novel laser distance measurement system was developed. It provides the angle resolved measurement of the biaxial deformation of a fibre-reinforced polymer composite rotor with micron uncertainty at surface speeds of more than 300 m/s. Furthermore, a simulation procedure combining a finite element model and a damage mechanics model is applied. A comparison of the measured data and the numerically calculated data is performed to validate the simulation towards rotor expansion. This validating procedure can be used for a model calibration in the future. The simulation procedure could be used to investigate different damage-test cases of the rotor, in order to define its structural behaviour without further experiments.

High-speed photography. Technique and evolution

International Nuclear Information System (INIS)

Sanchez-Tembleque, R.

1981-01-01

It is intended to present some general considerations about ''Higg-speed photography'' as a tool of work common in mos research laboratories in the world. ''High-speed photography'' relies on the principles of photography of actions, that change rapidly with the time. The evolution of this technique goes along with the discovering of new phenomena in wich higher speeds are involved. At present is normal to deal with changing rates involving picoseconds times (10 -12 s) and new developments on the field of femtosecond (10 -15 s) theoretically are contemplated. (author)

Review of High-Speed Fiber Optic Grating Sensors Systems

Energy Technology Data Exchange (ETDEWEB)

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.

Numerical simulation and experiments of precision bar cutting based on high speed and restrained state

International Nuclear Information System (INIS)

Song, J.L.; Li, Y.T.; Liu, Z.Q.; Fu, J.H.; Ting, K.L.

2009-01-01

According to the disadvantages of conventional bar cutting technology such as low-cutting speed, inferior section quality, high-processing cost and so on, a kind of novel precision bar cutting technology has been proposed. The cutting mechanism has also been analyzed. Finite element numerical simulation of the bar cutting process under different working conditions has been carried out with DEFORM. The stress and strain fields at different cutting speed and the variation curves of the cutting force and appropriate cutting parameters have been obtained. Scanning electron microscopy analysis of the cutting surface showed that the finite-element simulation result is correct and better cutting quality can be obtained with the developed bar cutting technology and equipment based on high speed and restrained state

Application of high speed machining technology in aviation

Science.gov (United States)

Bałon, Paweł; Szostak, Janusz; Kiełbasa, Bartłomiej; Rejman, Edward; Smusz, Robert

2018-05-01

Aircraft structures are exposed to many loads during their working lifespan. Every particular action made during a flight is composed of a series of air movements which generate various aircraft loads. The most rigorous requirement which modern aircraft structures must fulfill is to maintain their high durability and reliability. This requirement involves taking many restrictions into account during the aircraft design process. The most important factor is the structure's overall mass, which has a crucial impact on both utility properties and cost-effectiveness. This makes aircraft one of the most complex results of modern technology. Additionally, there is currently an increasing utilization of high strength aluminum alloys, which requires the implementation of new manufacturing processes. High Speed Machining technology (HSM) is currently one of the most important machining technologies used in the aviation industry, especially in the machining of aluminium alloys. The primary difference between HSM and other milling techniques is the ability to select cutting parameters - depth of the cut layer, feed rate, and cutting speed in order to simultaneously ensure high quality, precision of the machined surface, and high machining efficiency, all of which shorten the manufacturing process of the integral components. In this paper, the authors explain the implementation of the HSM method in integral aircraft constructions. It presents the method of the airframe manufacturing method, and the final results. The HSM method is compared to the previous method where all subcomponents were manufactured by bending and forming processes, and then, they were joined by riveting.

High-Speed Videography Instrumentation And Procedures

Science.gov (United States)

Miller, C. E.

1982-02-01

High-speed videography has been an electronic analog of low-speed film cameras, but having the advantages of instant-replay and simplicity of operation. Recent advances have pushed frame-rates into the realm of the rotating prism camera. Some characteristics of videography systems are discussed in conjunction with applications in sports analysis, and with sports equipment testing.

Satellite retrieved cloud optical thickness sensitive to surface wind speed in the subarctic marine boundary layer

International Nuclear Information System (INIS)

Glantz, Paul

2010-01-01

The optical and microphysical properties of low level marine clouds, presented over the Norwegian Sea and Barents Sea, have been investigated for the period 2000-2006. The air masses were transported for more or less seven days over the warmer North Atlantic before they arrived at the area investigated. The main focus in this study is on investigating the relationship between cloud optical thickness (COT) and surface wind speed (U 10m ) using satellite retrievals in combination with operational meteorological data. A relatively strong correlation (R 2 = 0.97) is obtained for wind speeds up to 12 m s -1 , in air masses that were probably to a major degree influenced by wind shears and to a minor degree by buoyancy. The relationship (U 2.5 ) is also in between those most commonly found in the literature for water vapor (∼U 1 ) and sea salt (∼U 3.4 ). The present results highlight the magnitude of marine sea-spray influence on COT and their global climatic importance.

Shelter Index and a simple wind speed parameter to characterize vegetation control of sand transport threshold and Flu

Science.gov (United States)

Gillies, J. A.; Nield, J. M.; Nickling, W. G.; Furtak-Cole, E.

2014-12-01

Wind erosion and dust emissions occur in many dryland environments from a range of surfaces with different types and amounts of vegetation. Understanding how vegetation modulates these processes remains a research challenge. Here we present results from a study that examines the relationship between an index of shelter (SI=distance from a point to the nearest upwind vegetation/vegetation height) and particle threshold expressed as the ratio of wind speed measured at 0.45 times the mean plant height divided by the wind speed at 17 m when saltation commences, and saltation flux. The results are used to evaluate SI as a parameter to characterize the influence of vegetation on local winds and sediment transport conditions. Wind speed, wind direction, saltation activity and point saltation flux were measured at 35 locations in defined test areas (~13,000 m2) in two vegetation communities: mature streets of mesquite covered nebkhas and incipient nebkhas dominated by low mesquite plants. Measurement positions represent the most open areas, and hence those places most susceptible to wind erosion among the vegetation elements. Shelter index was calculated for each measurement position for each 10° wind direction bin using digital elevation models for each site acquired using terrestrial laser scanning. SI can show the susceptibility to wind erosion at different time scales, i.e., event, seasonal, or annual, but in a supply-limited system it can fail to define actual flux amounts due to a lack of knowledge of the distribution of sediment across the surface of interest with respect to the patterns of SI.

Role of cavitation in high-speed droplet impact problems

Science.gov (United States)

Kondo, Tomoki; Ando, Keita

2014-11-01

High-speed droplet impact is found in physical cleaning using liquid jets, but its mechanisms for particle removal from target surfaces are yet unclear. In this study, we explore the possibility of having cavitation inside the droplet. The pressure evolution within a droplet colliding with a flat surface of deformable materials is determined by multicomponent Euler equations. Dynamics of cavitation bubbles heterogeneously nucleated from preexisting nuclei are determined from Rayleigh-Plesset calculations according to the pressure evolution within the droplet in one-way-coupling manner. The simulation shows that cavitation indeed occurs due to tension that arises from the water hammer shock reflection at the droplet interface. The role of cavitation including pressure emission from its collapse is to be discussed based on the one-way-coupling computations.

The role of high speed photography in plasma instability research on the AEC tokamak

International Nuclear Information System (INIS)

Fletcher, J.D.; Coster, D.P.; De Villiers, J.A.M.; Kotze, P.B.; Nothnagel, G.; O'Mahony, J.R.; Roberts, D.E.; Sherwell, D.

1986-01-01

High speed cine photography is a useful diagnostic aid for studying plasma behaviour and plasma surface interactions in fusion research devices like tokamaks. Such a system has been installed on the AEC tokamak. This paper reports some preliminary results obtained during typical plasma discharges

Integrated computer network high-speed parallel interface

International Nuclear Information System (INIS)

Frank, R.B.

1979-03-01

As the number and variety of computers within Los Alamos Scientific Laboratory's Central Computer Facility grows, the need for a standard, high-speed intercomputer interface has become more apparent. This report details the development of a High-Speed Parallel Interface from conceptual through implementation stages to meet current and future needs for large-scle network computing within the Integrated Computer Network. 4 figures

High-speed and intercity passenger rail testing strategy.

Science.gov (United States)

2013-05-01

This high-speed and intercity passenger rail (HSIPR) testing strategy addresses the requirements for testing of high-speed train sets and technology before introduction to the North American railroad system. The report documents the results of a surv...

Application of high-speed photography to hydrodynamic instability research

International Nuclear Information System (INIS)

Chang Lihua; Li Zuoyou; Xiao Zhengfei; Zou Liyong; Liu Jinhong; Xiong Xueshi

2012-01-01

High-speed photography is used to study the Rayleigh-Taylor instability of air-water interface driven by high- pressure exploding gas. Clear images illustrating the instability are obtained, along with the air bubble peak speed and turbulent mixing speed. The RM (Richtmyer-Meshkov) instability of air/SF 6 interface driven by shock wave is also researched by using high-speed Schlieren technique on the horizontal shock tube and primary experimental results are obtained, which show the change of the turbulent mixing region clearly. (authors)

Development of high-speed video cameras

Science.gov (United States)

Etoh, Takeharu G.; Takehara, Kohsei; Okinaka, Tomoo; Takano, Yasuhide; Ruckelshausen, Arno; Poggemann, Dirk

2001-04-01

Presented in this paper is an outline of the R and D activities on high-speed video cameras, which have been done in Kinki University since more than ten years ago, and are currently proceeded as an international cooperative project with University of Applied Sciences Osnabruck and other organizations. Extensive marketing researches have been done, (1) on user's requirements on high-speed multi-framing and video cameras by questionnaires and hearings, and (2) on current availability of the cameras of this sort by search of journals and websites. Both of them support necessity of development of a high-speed video camera of more than 1 million fps. A video camera of 4,500 fps with parallel readout was developed in 1991. A video camera with triple sensors was developed in 1996. The sensor is the same one as developed for the previous camera. The frame rate is 50 million fps for triple-framing and 4,500 fps for triple-light-wave framing, including color image capturing. Idea on a video camera of 1 million fps with an ISIS, In-situ Storage Image Sensor, was proposed in 1993 at first, and has been continuously improved. A test sensor was developed in early 2000, and successfully captured images at 62,500 fps. Currently, design of a prototype ISIS is going on, and, hopefully, will be fabricated in near future. Epoch-making cameras in history of development of high-speed video cameras by other persons are also briefly reviewed.

Surface Transportation Security Priority Assessment

Science.gov (United States)

2010-03-01

intercity buses), and pipelines, and related infrastructure (including roads and highways), that are within the territory of the United States...Modernizing the information technology infrastructure used to vet the identity of travelers and transportation workers  Using terrorist databases to...examination of persons travelling , surface transportation modes tend to operate in a much more open environment, making it difficult to screen workers

Rotating speed effect on electronic transport behaviors of Ni–Nb–Zr–H glassy alloys

International Nuclear Information System (INIS)

Fukuhara, Mikio

2012-01-01

Highlights: ► The electronic transport behaviors of (Ni 0.39 Nb 0.25 Zr 0.35 ) 100−y H y (0 ≤ y ≤ 15) glassy alloys, which produced by rotating (or quenching) speeds of 3000 and 10,000 rpm, have been studied as a function of hydrogen content. ► The resistivity for (Ni 0.39 Nb 0.25 Zr 0.35 ) 97.8 H 2.2 alloy, produced by rotating speed of 10,000 rpm, displayed 0.1 nΩ cm, which is 0.01% of silver (1.62 μΩ cm) at room temperature, between 40 and 252 K. ► Supercooling of the molten alloy induces a superior ballistic conductor and a room-temperature Coulomb oscillation. - Abstract: The electronic transport behaviors of (Ni 0.39 Nb 0.25 Zr 0.35 ) 100−y H y (0 ≤ y ≤ 15) glassy alloys, produced by rotating (or quenching) speeds of 3000 and 10,000 rpm, have been studied as a function of hydrogen content. These alloys show semiconducting, superior ballistic transport, superconducting and electric current-induced Coulomb oscillation, as hydrogen content increases. The resistivity for (Ni 0.39 Nb 0.25 Zr 0.35 ) 97.8 H 2.2 alloy, produced by rotating speed of 10,000 rpm, displayed 0.1 nΩ cm, which is 0.01% of silver (1.62 μΩ cm) at room temperature, between 40 and 252 K. The Coulomb oscillation of the 10,000 rpm-(Ni 0.39 Nb 0.25 Zr 0.35 ) 95.2 H 4.8 alloy is about 4-fold larger than that of the 3000 rpm-(Ni 0.39 Nb 0.25 Zr 0.35 ) 91.1 H 8.9 alloy. Supercooling of the molten alloy induces a superior ballistic conductor and a room-temperature Coulomb oscillation at lower and higher hydrogen contents, respectively.

High-speed AFM of human chromosomes in liquid

Energy Technology Data Exchange (ETDEWEB)

Picco, L M; Dunton, P G; Ulcinas, A; Engledew, D J; Miles, M J [H H Wills Physics Laboratory and IRC in Nanotechnology, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Hoshi, O; Ushiki, T [Division of Microscopic Anatomy and Bio-Imaging, Department of Cellular Function, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi-Dori 1, Niigata, 951-8150 (Japan)], E-mail: m.j.miles@bristol.ac.uk

2008-09-24

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.

Characterizing speed-independence of high-level designs

DEFF Research Database (Denmark)

Kishinevsky, Michael; Staunstrup, Jørgen

1994-01-01

This paper characterizes the speed-independence of high-level designs. The characterization is a condition on the design description ensuring that the behavior of the design is independent of the speeds of its components. The behavior of a circuit is modeled as a transition system, that allows data...... types, and internal as well as external non-determinism. This makes it possible to verify the speed-independence of a design without providing an explicit realization of the environment. The verification can be done mechanically. A number of experimental designs have been verified including a speed-independent...

Development of ultra high speed photographic system using high repetition rate visible laser

International Nuclear Information System (INIS)

Lee, Jong Min; Cha, Byung Hun; Kim, Sung Ho; Kim, Jung Bog; Lim, Chang Hwan; Cha, Hyung Ki; Song, Kyu Seok; Lee, Byung Deok; Rhi, Jong Hoon; Baik, Dae Hyun; Han, Jae Min; Rho, Si Pyo; Lee, Byung Cheol; Jeong, Do Yung; Choi, An Seong; Jeong, Chan Ik; Park, Dae Ung; Jeong, Sung Min; Lee, Sang Kil; Kim, Heon Jun; Jang, Rae gak; Jo, Do Hun; Park, Min Young

1992-12-01

The goal of this project is to develop and commercialize a high speed photographic system equipped with a high repetition rate visible laser. The developed system provides the characteristics of high time resolution and large number of frames. The system consists of 10 W air cooled CVL or a 30 W water cooled CVL, a rotating drum-type high speed camera with the framing rate of 35,000 fps, and a automatic control device. The system has the performance of 10 nsec time resolution, 35,000 fps framing rate, and 250 picture frames. The high speed photographic systems are widely applied to the fields such as high-efficient engine development, high-speed vibration analysis, shock wave propagation study, flow visualization analysis, weapon development, etc. (Author)

Modification of AISI M2 high speed tool steels after laser surface melting under different operation conditions; Modificacion de los aceros rapidos de herramientas AISI M2 por fusion superficial con laser bajo diferentes condiciones de operacion

Energy Technology Data Exchange (ETDEWEB)

Arias, J.; Cabeza, M.; Castro, G.; Feijoo, I.; Merino, P.; Pena, G.

2010-07-01

We applied a laser surface melting treatment to AISIM2 high-speed steel hardened and tempered- and studied the resulting surface characteristics (microstructure) and mechanical behavior (hardness and wear performance). The steel was treated using a Nd:YAG continuous-wave laser with different operation conditions. The influence of the laser processing parameters on the single tracks and on melted surface layer obtained by multipass system with 50% overlap were studied. The microstructure for all conditions is formed by MC- and M{sub 2}C-type carbides, martensite and retained austenite; the quantities of this phase depends on the operations conditions. It has been determined that low levels of power density and high speed scanning of the beam leads to greater homogeneity in the microstructure with high hardness values and wear resistance. (Author) 26 refs.

Assess the feasibility of the high-speed railway construction in China by measuring the traffic demand elastic

Science.gov (United States)

Yu, Nan; Cao, Yu

2017-05-01

The traffic demand elastic is proposed as a new indicator in this study to measure the feasibility of the high-speed railway construction in a more intuitive way. The Matrix Completion (MC) and Semi-Supervised Support Vector Machine (S3VM) are used to realize the measurement and prediction of this index on the basis of the satisfaction investigation on the 326 inter-city railways in china. It is demonstrated that instead of calculating the economic benefits brought by the construction of high-speed railway, this indicator can find the most urgent railways to be improved by directly evaluate the existing railway facilities from the perspective of transportation service improvement requirements.

Minimum Plate Thickness in High-Speed Craft

DEFF Research Database (Denmark)

Pedersen, Preben Terndrup; Zhang, Shengming

1998-01-01

The minimum plate thickness requirements specified by the classification societies for high-speed craft are supposed to ensure adequate resistance to impact loads such as collision with floating objects and objects falling on the deck. The paper presents analytical methods of describing such impact...... phenomena and proposes performance requirements instead of thickness requirements for hull panels in high-speed craft made of different building materials....

Effects of nearby surface features on wind speed at a nuclear plant meteorological station

International Nuclear Information System (INIS)

Nielsen, N.A.; Goodwin, R.J.; Pittman, D.E.

1984-01-01

There is a definite cause and effect relationship between the trees in the vicinity of the meteorological tower and the wind speed at the 10-meter level on the meteorological tower. For the affected directions, horizontal wind speed is significantly reduced below what it would be for that level if the trees were not present. This effect is only slightly less for the 10:1 exposure achieved with the 1977 tree clearing, which illustrates that meeting this commonly accepted distance to height ratio does not assure representativeness of 10-meter data collected at a nuclear plant site. The somewhat stronger effect for winds from the south through southwest directions may be partly attributable to the abrupt change in roughness and elevation encountered by air moving at an angle or directly across the reservoir, which is 3.5 to 5.0 kilometers wide at this site. This general reduction in wind speed values below what would be expected at the plant location will result in biased dispersion estimates. Calculated relative concentration values for releases treated as ground-level or building-wake releases would be larger than actual concentrations. While this would provide conservative concentration values, radioactive plume transport calculations would be nonconservative. The calculated, or predicted, transport rate would be slower than the actual transport rate. Such local biases affecting the spatial representativeness of airflow at 10 meters are a primary reason for TVA's decision to use 46-meter wind data for ground-level transport and diffusion modeling in its radiological emergency preparedness program

The large scale and long term evolution of the solar wind speed distribution and high speed streams

International Nuclear Information System (INIS)

Intriligator, D.S.

1977-01-01

The spatial and temporal evolution of the solar wind speed distribution and of high speed streams in the solar wind are examined. Comparisons of the solar wind streaming speeds measured at Earth, Pioneer 11, and Pioneer 10 indicate that between 1 AU and 6.4 AU the solar wind speed distributions are narrower (i.e. the 95% value minus the 5% value of the solar wind streaming speed is less) at extended heliocentric distances. These observations are consistent with one exchange of momentum in the solar wind between high speed streams and low speed streams as they propagate outward from the Sun. Analyses of solar wind observations at 1 AU from mid 1964 through 1973 confirm the earlier results reported by Intriligator (1974) that there are statistically significant variations in the solar wind in 1968 and 1969, years of solar maximum. High speed stream parameters show that the number of high speed streams in the solar wind in 1968 and 1969 is considerably more than the predicted yearly average, and in 1965 and 1972 less. Histograms of solar wind speed from 1964 through 1973 indicate that in 1968 there was the highest percentage of elevated solar wind speeds and in 1965 and 1972 the lowest. Studies by others also confirm these results although the respective authors did not indicate this fact. The duration of the streams and the histograms for 1973 imply a shifting in the primary stream source. (Auth.)

Probing the nanoscale with high-speed interferometry of an impacting drop

KAUST Repository

Thoroddsen, Sigurdur T.

2017-02-28

The simple phenomenon of a water drop falling onto a glass plate may seem like a trivial fluid mechanics problem. However, detailed imaging has shown that this process is highly complex and a small air-bubble is always entrapped under the drop when it makes contact with the solid. This bubble can interfere with the uniformity of spray coatings and degrade inkjet fabrication of displays etc. We will describe how we use high-speed interferometry at 5 million frames per second to understand the details of this process. As the impacting drop approaches the solid, the dynamics are characterized by a balance between the lubrication pressure in the thin air layer and the inertia of the bot-tom of the drop. This deforms the drop, forming a dimple at its bottom and making the drop touch the surface along a ring, thereby entrapping the air-layer, which is typically 1-3 mu m thick. This air-layer can be highly compressed and the deceleration of the bottom of the drop can be as large as 300,000 g. We describe how the thicknessevolution of the lubricating air-layer is extracted from following the interference fringes between frames. Two-color interferometry is also used to extract absolute layer thicknesses. Finally, we identify the effects of nanometric surface roughness on the first contact of the drop with the substrate. Here we need to resolve the 100 nm thickness changes occurring during 200 ns intervals, requiring these state of the art high-speed cameras. Surprisingly, we see a ring of micro-bubbles marking the first contact of the drop with the glass, only for microscope slides, which have a typical roughness of 20 nm, while such rings are absent for drop impacts onto molecularly smooth mica surfaces.

Probing the nanoscale with high-speed interferometry of an impacting drop

KAUST Repository

Thoroddsen, Sigurdur T; Li, Erqiang; Vakarelski, Ivan Uriev; Langley, Kenneth

2017-01-01

The simple phenomenon of a water drop falling onto a glass plate may seem like a trivial fluid mechanics problem. However, detailed imaging has shown that this process is highly complex and a small air-bubble is always entrapped under the drop when it makes contact with the solid. This bubble can interfere with the uniformity of spray coatings and degrade inkjet fabrication of displays etc. We will describe how we use high-speed interferometry at 5 million frames per second to understand the details of this process. As the impacting drop approaches the solid, the dynamics are characterized by a balance between the lubrication pressure in the thin air layer and the inertia of the bot-tom of the drop. This deforms the drop, forming a dimple at its bottom and making the drop touch the surface along a ring, thereby entrapping the air-layer, which is typically 1-3 mu m thick. This air-layer can be highly compressed and the deceleration of the bottom of the drop can be as large as 300,000 g. We describe how the thicknessevolution of the lubricating air-layer is extracted from following the interference fringes between frames. Two-color interferometry is also used to extract absolute layer thicknesses. Finally, we identify the effects of nanometric surface roughness on the first contact of the drop with the substrate. Here we need to resolve the 100 nm thickness changes occurring during 200 ns intervals, requiring these state of the art high-speed cameras. Surprisingly, we see a ring of micro-bubbles marking the first contact of the drop with the glass, only for microscope slides, which have a typical roughness of 20 nm, while such rings are absent for drop impacts onto molecularly smooth mica surfaces.

Experimental Study of Low Speed Sensorless Control of PMSM Drive Using High Frequency Signal Injection

Directory of Open Access Journals (Sweden)

Jyoti Agrawal

2016-01-01

Full Text Available Conventional techniques for sensorless control of permanent magnet synchronous motor drive (PMSM, which requires information on rotor position, are reviewed, and recent developments in this area are introduced in this paper along with their inherent advantages and drawbacks. The paper presents an improved method for sensorless speed control of PMSM drive with emphasis placed on signal injection method. This signal injection method examines the control performance of sensorless PMSM drive by injecting signal externally and thereby sensing the rotor position. The main objective of this drive system is to have speed control at standstill and low speed regions. Several tests are carried out to demonstrate the ability of proposed models at different operating conditions with the help of simulation results in Matlab/Simulink environment. Simulation results confirm that the proposed sensorless control approach of PMSM can achieve high performance at standstill and low speeds but not at very high speeds. An experimental setup is implemented using a 1HP surface mounted (SM PMSM and DsPICDEM^TM MCHV-2 development board, to check the validity of simulation results.

Rat muscle blood flows during high-speed locomotion

International Nuclear Information System (INIS)

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

1985-01-01

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

Experimental and numerical study of plastic shear instability under high-speed loading conditions

International Nuclear Information System (INIS)

Sokovikov, Mikhail; Chudinov, Vasiliy; Bilalov, Dmitry; Oborin, Vladimir; Uvarov, Sergey; Plekhov, Oleg; Terekhina, Alena; Naimark, Oleg

2014-01-01

The behavior of specimens dynamically loaded during the split Hopkinson (Kolsky) bar tests in a regime close to simple shear conditions was studied. The lateral surface of the specimens was investigated in a real-time mode with the aid of a high-speed infra-red camera CEDIP Silver 450M. The temperature field distribution obtained at different time made it possible to trace the evolution of plastic strain localization. The process of target perforation involving plug formation and ejection was examined using a high-speed infra-red camera and a VISAR velocity measurement system. The microstructure of tested specimens was analyzed using an optical interferometer-profilometer and a scanning electron microscope. The development of plastic shear instability regions has been simulated numerically

Toward reduced transport errors in a high resolution urban CO2 inversion system

Directory of Open Access Journals (Sweden)

Aijun Deng

2017-05-01

Full Text Available We present a high-resolution atmospheric inversion system combining a Lagrangian Particle Dispersion Model (LPDM and the Weather Research and Forecasting model (WRF, and test the impact of assimilating meteorological observation on transport accuracy. A Four Dimensional Data Assimilation (FDDA technique continuously assimilates meteorological observations from various observing systems into the transport modeling system, and is coupled to the high resolution CO2 emission product Hestia to simulate the atmospheric mole fractions of CO2. For the Indianapolis Flux Experiment (INFLUX project, we evaluated the impact of assimilating different meteorological observation systems on the linearized adjoint solutions and the CO2 inverse fluxes estimated using observed CO2 mole fractions from 11 out of 12 communications towers over Indianapolis for the Sep.-Nov. 2013 period. While assimilating WMO surface measurements improved the simulated wind speed and direction, their impact on the planetary boundary layer (PBL was limited. Simulated PBL wind statistics improved significantly when assimilating upper-air observations from the commercial airline program Aircraft Communications Addressing and Reporting System (ACARS and continuous ground-based Doppler lidar wind observations. Wind direction mean absolute error (MAE decreased from 26 to 14 degrees and the wind speed MAE decreased from 2.0 to 1.2 m s–1, while the bias remains small in all configurations (< 6 degrees and 0.2 m s–1. Wind speed MAE and ME are larger in daytime than in nighttime. PBL depth MAE is reduced by ~10%, with little bias reduction. The inverse results indicate that the spatial distribution of CO2 inverse fluxes were affected by the model performance while the overall flux estimates changed little across WRF simulations when aggregated over the entire domain. Our results show that PBL wind observations are a potent tool for increasing the precision of urban meteorological reanalyses

Modeling and analysis of surface roughness effects on sputtering, reflection, and sputtered particle transport

International Nuclear Information System (INIS)

Brooks, J.N.; Ruzic, D.N.

1990-01-01

The microstructure of the redeposited surface in tokamaks may affect sputtering and reflection properties and subsequent particle transport. This subject has been studied numerically using coupled models/codes for near-surface plasma particle kinetic transport (WBC code) and rough surface sputtering (fractal-TRIM). The coupled codes provide an overall Monte Carlo calculation of the sputtering cascade resulting from an initial flux of hydrogen ions. Beryllium, carbon, and tungsten surfaces are analyzed for typical high recycling, oblique magnetic field, divertor conditions. Significant variations in computed sputtering rates are found with surface roughness. Beryllium exhibits high D-T and self-sputtering coefficients for the plasma regime studied (T e = 30-75 eV). Carbon and tungsten sputtering is significantly lower. 9 refs., 6 figs., 1 tab

Production of intermediate energy beams by high speed rotors

International Nuclear Information System (INIS)

Nutt, C.W.; Bale, T.J.; Cosgrove, P.; Kirby, M.J.

1975-01-01

A rotor apparatus intended for the study of gas/surface interaction processes is presently nearing completion. The carbon fiber rotors under consideration are constructed with shapes derived from long thin cylindrical rods oriented with the longest axis in a horizontal plane, and spun in a horizontal plane about an axis which is perpendicular to the long axis and passes through the mid-point of the cylinder. The beam formation processes are discussed and rotor diagrams presented. Performance of these types of high speed rotor show them to have a very important future as sources of intermediate energy molecular beams

High speed friction microscopy and nanoscale friction coefficient mapping

International Nuclear Information System (INIS)

Bosse, James L; Lee, Sungjun; Huey, Bryan D; Andersen, Andreas Sø; Sutherland, Duncan S

2014-01-01

As mechanical devices in the nano/micro length scale are increasingly employed, it is crucial to understand nanoscale friction and wear especially at technically relevant sliding velocities. Accordingly, a novel technique has been developed for friction coefficient mapping (FCM), leveraging recent advances in high speed AFM. The technique efficiently acquires friction versus force curves based on a sequence of images at a single location, each with incrementally lower loads. As a result, true maps of the coefficient of friction can be uniquely calculated for heterogeneous surfaces. These parameters are determined at a scan velocity as fast as 2 mm s −1 for microfabricated SiO 2 mesas and Au coated pits, yielding results that are identical to traditional speed measurements despite being ∼1000 times faster. To demonstrate the upper limit of sliding velocity for the custom setup, the friction properties of mica are reported from 200 µm s −1 up to 2 cm s −1 . While FCM is applicable to any AFM and scanning speed, quantitative nanotribology investigations of heterogeneous sliding or rolling components are therefore uniquely possible, even at realistic velocities for devices such as MEMS, biological implants, or data storage systems. (paper)

High-Speed Photo-Polarimetry of Magnetic Cataclysmic Variables

Directory of Open Access Journals (Sweden)

S. B. Potter

2015-02-01

Full Text Available I review recent highlights of the SAAO High-speed Photo-POlarimeter (HIPPO on the study of magnetic Cataclysmic Variables. Its high-speed capabilities are demonstrated with example observations made of the intermediate polar NY Lup and the polar IGRJ14536-5522.

Trend on High-speed Power Line Communication Technology

Science.gov (United States)

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.

A high speed digital noise generator

Science.gov (United States)

Obrien, J.; Gaffney, B.; Liu, B.

In testing of digital signal processing hardware, a high speed pseudo-random noise generator is often required to simulate an input noise source to the hardware. This allows the hardware to be exercised in a manner analogous to actual operating conditions. In certain radar and communication environments, a noise generator operating at speeds in excess of 60 MHz may be required. In this paper, a method of generating high speed pseudo-random numbers from an arbitrarily specified distribution (Gaussian, Log-Normal, etc.) using a transformation from a uniform noise source is described. A noise generator operating at 80 MHz has been constructed. Different distributions can be readily obtained by simply changing the ROM set. The hardware and test results will be described. Using this approach, the generation of pseudo-random sequences with arbitrary distributions at word rates in excess of 200 MHz can be readily achieved.

Compressibility, turbulence and high speed flow

CERN Document Server

Gatski, Thomas B

2013-01-01

Compressibility, Turbulence and High Speed Flow introduces the reader to the field of compressible turbulence and compressible turbulent flows across a broad speed range, through a unique complimentary treatment of both the theoretical foundations and the measurement and analysis tools currently used. The book provides the reader with the necessary background and current trends in the theoretical and experimental aspects of compressible turbulent flows and compressible turbulence. Detailed derivations of the pertinent equations describing the motion of such turbulent flows is provided and an extensive discussion of the various approaches used in predicting both free shear and wall bounded flows is presented. Experimental measurement techniques common to the compressible flow regime are introduced with particular emphasis on the unique challenges presented by high speed flows. Both experimental and numerical simulation work is supplied throughout to provide the reader with an overall perspective of current tre...

Cell formation effects on the burning speeds and flame front area of synthetic gas at high pressures and temperatures

International Nuclear Information System (INIS)

Askari, Omid; Elia, Mimmo; Ferrari, Matthew; Metghalchi, Hameed

2017-01-01

Highlights: • Effect of cell formation on burning speed and flame surface area is investigated. • A new developed non-dimensional number called cellularity factor is introduced. • Cellular burning speed and mass burning rate are calculated using differential based multi-shell model. • Flame instability is studied using thermo-diffusive and hydrodynamics effects. • Power law correlations are developed for cellular burning speeds and mass burning rates. - Abstract: Cellular burning speeds and mass burning rates of premixed syngas/oxidizer/diluent (H_2/CO/O_2/He) have been determined at high pressures and temperatures over a wide range of equivalence ratios which are at engine-relevant conditions. Working on high pressure combustion helps to reduce the pollution and increase the energy efficiency in combustion devices. The experimental facilities consisted of two spherical and cylindrical chambers. The spherical chamber, which can withstand high pressures up to 400 atm, was used to collect pressure rise data due to combustion, to calculate cellular burning speed and mass burning rate. For flame structure and instability analysis the cylindrical chamber was used to take pictures of propagating flame using a high speed CMOS camera and a schlieren photography system. A new differential based multi-shell model based on pressure rise data was used to determine the cellular burning speed and mass burning rate. In this paper, cellular burning speed and mass burning rate of H_2/CO/O_2/He mixture have been measured for a wide range of equivalence ratios from 0.6 to 2, temperatures from 400 to 750 K and pressures from 2 to 50 atm for three hydrogen concentrations of 5, 10 and 25% in the syngas. The power law correlations for cellular burning speed and mass burning rate were developed as a function of equivalence ratio, temperature and pressure. In this study a new developed parameter, called cellularity factor, which indicates the cell formation effect on flame

Onshore Wind Speed Modulates Microbial Aerosols along an Urban Waterfront

Directory of Open Access Journals (Sweden)

M. Elias Dueker

2017-11-01

Full Text Available Wind blowing over aquatic and terrestrial surfaces produces aerosols, which include microbial aerosols. We studied the effect of onshore wind speeds on aerosol concentrations as well as total and culturable microbial aerosols (bacterial and viral at an urban waterfront (New York, NY, United States of America. We used two distinct methods to characterize microbial aerosol responses to wind speed: A culture-based exposure-plate method measuring viable bacterial deposition near-shore (CFU accumulation rate; and a culture-independent aerosol sampler-based method measuring total bacterial and viral aerosols (cells m−3 air. While ambient coarse (>2 µm and fine (0.3–2 µm aerosol particle number concentrations (regulated indicators of air quality decreased with increasing onshore wind speeds, total and depositing culturable bacterial aerosols and total viral aerosols increased. Taxonomic identification of the 16S rDNA of bacterial aerosol isolates suggested both terrestrial and aquatic sources. Wind appears to increase microbial aerosol number concentrations in the near-shore environment by onshore transport at low wind speeds (<4 m s−1, and increased local production and transport of new microbial aerosols from adjacent water surfaces at higher wind speeds (>4 m s−1. This study demonstrates a wind-modulated microbial connection between water and air in the coastal urban environment, with implications for public health management and urban microbial ecology.

High-speed solar wind flow parameters at 1 AU

International Nuclear Information System (INIS)

Feldman, W.C.; Asbridge, J.R.; Bame, S.J.; Gosling, J.T.

1976-01-01

To develop a set of constraints for theories of solar wind high-speed streams, a detailed study was made of the fastest streams observed at 1 AU during the time period spanning March 1971 through July 1974. Streams were accepted for study only if (1) the maximum speed exceeded 650 km s -1 ; (2) effects of stream-stream dynamical interaction on the flow parameters could be safely separated from the intrinsic characteristics of the high-speed regions; (3) the full width at half maximum (FWHM) of the stream when mapped back to 20 solar radii by using a constant speed approximation was greater than 45degree in Carrington longitude; and (4) there were no obvious solar-activity-induced contaminating effects. Nineteen streams during this time interval satisfied these criteria. Average parameters at 1 AU for those portions of these streams above V=650 km s -1 are given.Not only is it not presently known why electrons are significantly cooler than the protons within high-speed regions, but also observed particle fluxes and convected energy fluxes for speed greater than 650 km s -1 are substantially larger than those values predicted by any of the existing theories of solar wind high-speed streams. More work is therefore needed in refining present solar wind models to see whether suitable modifications and/or combinations of existing theories based on reasonable coronal conditions can accommodate the above high-speed flow parameters

High-Speed Interferometry Under Impacting Drops

KAUST Repository

Langley, Kenneth R.; Li, Erqiang; Thoroddsen, Sigurdur T

2017-01-01

Over the last decade the rapid advances in high-speed video technology, have opened up to study many multi-phase fluid phenomena, which tend to occur most rapidly on the smallest length-scales. One of these is the entrapment of a small bubble under a drop impacting onto a solid surface. Here we have gone from simply observing the presence of the bubble to detailed imaging of the formation of a lubricating air-disc under the drop center and its subsequent contraction into the bubble. Imaging the full shape-evolution of the air-disc has required μm and sub-μs space and time resolutions. Time-resolved 200 ns interferometry with monochromatic light, has allowed us to follow individual fringes to obtain absolute air-layer thicknesses, based on the eventual contact with the solid. We can follow the evolution of the dimple shape as well as the compression of the gas. The improved imaging has also revealed new levels of detail, like the nature of the first contact which produces a ring of micro-bubbles, highlighting the influence of nanometric surface roughness. Finally, for impacts of ultra-viscous drops we see gliding on ~100 nm thick rarified gas layers, followed by extreme wetting at numerous random spots.

High-Speed Interferometry Under Impacting Drops

KAUST Repository

Langley, Kenneth R.

2017-08-31

Over the last decade the rapid advances in high-speed video technology, have opened up to study many multi-phase fluid phenomena, which tend to occur most rapidly on the smallest length-scales. One of these is the entrapment of a small bubble under a drop impacting onto a solid surface. Here we have gone from simply observing the presence of the bubble to detailed imaging of the formation of a lubricating air-disc under the drop center and its subsequent contraction into the bubble. Imaging the full shape-evolution of the air-disc has required μm and sub-μs space and time resolutions. Time-resolved 200 ns interferometry with monochromatic light, has allowed us to follow individual fringes to obtain absolute air-layer thicknesses, based on the eventual contact with the solid. We can follow the evolution of the dimple shape as well as the compression of the gas. The improved imaging has also revealed new levels of detail, like the nature of the first contact which produces a ring of micro-bubbles, highlighting the influence of nanometric surface roughness. Finally, for impacts of ultra-viscous drops we see gliding on ~100 nm thick rarified gas layers, followed by extreme wetting at numerous random spots.

High Speed Water Sterilization Using One-Dimensional Nanostructures

KAUST Repository

Schoen, David T.; Schoen, Alia P.; Hu, Liangbing; Kim, Han Sun; Heilshorn, Sarah C.; Cui, Yi

2010-01-01

The removal of bacteria and other organisms from water is an extremely important process, not only for drinking and sanitation but also industrially as biofouling is a commonplace and serious problem. We here present a textile based multiscale device for the high speed electrical sterilization of water using silver nanowires, carbon nanotubes, and cotton. This approach, which combines several materials spanning three very different length scales with simple dying based fabrication, makes a gravity fed device operating at 100000 L/(h m2) which can inactivate >98% of bacteria with only several seconds of total incubation time. This excellent performance is enabled by the use of an electrical mechanism rather than size exclusion, while the very high surface area of the device coupled with large electric field concentrations near the silver nanowire tips allows for effective bacterial inactivation. © 2010 American Chemical Society.

High Speed Water Sterilization Using One-Dimensional Nanostructures

KAUST Repository

Schoen, David T.

2010-09-08

The removal of bacteria and other organisms from water is an extremely important process, not only for drinking and sanitation but also industrially as biofouling is a commonplace and serious problem. We here present a textile based multiscale device for the high speed electrical sterilization of water using silver nanowires, carbon nanotubes, and cotton. This approach, which combines several materials spanning three very different length scales with simple dying based fabrication, makes a gravity fed device operating at 100000 L/(h m2) which can inactivate >98% of bacteria with only several seconds of total incubation time. This excellent performance is enabled by the use of an electrical mechanism rather than size exclusion, while the very high surface area of the device coupled with large electric field concentrations near the silver nanowire tips allows for effective bacterial inactivation. © 2010 American Chemical Society.

Research on Aerodynamic Noise Reduction for High-Speed Trains

OpenAIRE

Zhang, Yadong; Zhang, Jiye; Li, Tian; Zhang, Liang; Zhang, Weihua

2016-01-01

A broadband noise source model based on Lighthill’s acoustic theory was used to perform numerical simulations of the aerodynamic noise sources for a high-speed train. The near-field unsteady flow around a high-speed train was analysed based on a delayed detached-eddy simulation (DDES) using the finite volume method with high-order difference schemes. The far-field aerodynamic noise from a high-speed train was predicted using a computational fluid dynamics (CFD)/Ffowcs Williams-Hawkings (FW-H)...

Nugget Structure Evolution with Rotation Speed for High-Rotation-Speed Friction-Stir-Welded 6061 Aluminum Alloy

Science.gov (United States)

Zhang, H. J.; Wang, M.; Zhu, Z.; Zhang, X.; Yu, T.; Wu, Z. Q.

2018-03-01

High-rotation-speed friction stir welding (HRS-FSW) is a promising technique to reduce the welding loads during FSW and thus facilitates the application of FSW for in situ fabrication and repair. In this study, 6061 aluminum alloy was friction stir welded at high-rotation speeds ranging from 3000 to 7000 rpm at a fixed welding speed of 50 mm/min, and the effects of rotation speed on the nugget zone macro- and microstructures were investigated in detail in order to illuminate the process features. Temperature measurements during HRS-FSW indicated that the peak temperature did not increase consistently with rotation speed; instead, it dropped remarkably at 5000 rpm because of the lowering of material shear stress. The nugget size first increased with rotation speed until 5000 rpm and then decreased due to the change of the dominant tool/workpiece contact condition from sticking to sliding. At the rotation speed of 5000 rpm, where the weld material experienced weaker thermal effect and higher-strain-rate plastic deformation, the nugget exhibited relatively small grain size, large textural intensity, and high dislocation density. Consequently, the joint showed superior nugget hardness and simultaneously a slightly low tensile ductility.

Balancing High-Speed Rotors at Low Speed

Science.gov (United States)

Giordano, J.; Zorzi, E.

1986-01-01

Flexible balancing reduces vibrations at operating speeds. Highspeed rotors in turbomachines dynamically balanced at fraction of operating rotor speed. New method takes into account rotor flexible rather than rigid.

The Impact of High-Speed Rail on Residents’ Travel Behavior and Household Mobility: A Case Study of the Beijing-Shanghai Line, China

Directory of Open Access Journals (Sweden)

Hongsheng Chen

2016-11-01

Full Text Available With the improvement of China’s high-speed rail network, there have been many economic and social benefits for local residents. Based on a questionnaire conducted in stations on the Beijing-Shanghai line, and through an analysis of high-speed rail passenger travel behavior and family relocation, we explored the social effects of high-speed rail. The study found that high-speed rail passengers are mainly young, highly educated, and have a middle to high income. However, with the popularization of high-speed rail, such differences in the social stratum of high-speed rail passengers are expected to disappear. Through an analysis of passenger travel status, we found that the areas surrounding high-speed rail stations are very accessible to the main cities, and are well connected by other public transport. With the emergence of the “high mobility era” based on the high-speed rail network, the separation of workplace and residence and the number of “double city” households are increasing, primarily in the Beijing-Tianjin and Shanghai-Nanjing (especially in Suzhou-Kunshan-Shanghai regions. In addition, high-speed rail introduces the possibility of household mobility, with 22.7% of the respondents in this study having relocated since the Beijing-Shanghai line opened. Household mobility is apparent primarily among big cities, with movement toward nearby cities. We also found that occupation, income, residence time, and schooling of children have a significant impact on households. With the improvement of high-speed rail networks, household mobility will become a common phenomenon and research on domestic mobility will continue to increase.

High-speed holographic camera

International Nuclear Information System (INIS)

Novaro, Marc

The high-speed holographic camera is a disgnostic instrument using holography as an information storing support. It allows us to take 10 holograms, of an object, with exposures times of 1,5ns, separated in time by 1 or 2ns. In order to get these results easily, no mobile part is used in the set-up [fr

Recent progress on high-speed optical transmission

Directory of Open Access Journals (Sweden)

Jianjun Yu

2016-05-01

Full Text Available The recently reported high spectral efficiency (SE and high-baud-rate signal transmission are all based on digital coherent optical communications and digital signal processing (DSP. DSP simplifies the reception of advanced modulation formats and also enables the major electrical and optical impairments to be processed and compensated in the digital domain, at the transmitter or receiver side. In this paper, we summarize the research progress on high-speed signal generation and detection and also show the progress on DSP for high-speed signal detection. We also report the latest progress on multi-core and multi-mode multiplexing.

Electron curing for high speed paper, film and foil converting

International Nuclear Information System (INIS)

Nablo, S.V.; Tripp, E.P.

1979-01-01

The status of self-shielded, compact electron processors for flexible web converting applications is reviewed. The uses of these units for a variety of laminating applications are described, with emphasis on the application techniques appropriate for low weight, (1 to 2 gm/m 2 ) 100% convertible adhesives. Performance data for electron cured adhesives with polyester/polyethylene systems is presented and compared with conventional urethane systems. The unique surface features of electron cured gravure coatings applied and cured at high speed are discussed, with reference to both paper and film substrates. An important advantage of electron curing of buried adhesive layers is the process quality control permitted by this 'all-electric' system. The performance characteristics of curing atmosphere control (inerting) for coatings are reviewed. Industrial experience with these processors has shown that effective inerting of coated flexible webs at speeds to 250 m/minute is both practical and economical. (author)

Single-Photon Tracking for High-Speed Vision

Directory of Open Access Journals (Sweden)

Istvan Gyongy

2018-01-01

Full Text Available Quanta Imager Sensors provide photon detections at high frame rates, with negligible read-out noise, making them ideal for high-speed optical tracking. At the basic level of bit-planes or binary maps of photon detections, objects may present limited detail. However, through motion estimation and spatial reassignment of photon detections, the objects can be reconstructed with minimal motion artefacts. We here present the first demonstration of high-speed two-dimensional (2D tracking and reconstruction of rigid, planar objects with a Quanta Image Sensor, including a demonstration of depth-resolved tracking.

A high-speed interface for multi-channel analyzer

International Nuclear Information System (INIS)

Shen Ji; Zheng Zhong; Qiao Chong; Chen Ziyu; Ye Yunxiu; Ye Zhenyu

2003-01-01

This paper presents a high-speed computer interface for multi-channel analyzer based on DMA technique. Its essential principle and operating procedure are introduced. By the detecting of γ spectrum of 137 Cs with the interface, it's proved that the interface can meet the requirements of high-speed data acquisition

Estimation of performance of a high-speed boat by using the Rankine source method; Kosokutei no rankinsosuho ni yoru seino suitei ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Eguchi, T [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)

1997-10-01

This paper describes estimation of performance of a high-speed boat by using the Rankine source method. An orthogonal coordinate system is considered, which uses the center of a hull as the zero point, and is made dimensionless by using the hull length. The catamaran boat or the single hull boat being the subject of the discussion is supposed to have a transom stern, and to be sailing at a constant speed in the -X direction. A governing equation and a border condition were formulated using disturbance speed potential and X-direction speed differentiation. An inverse specular image was employed as a specular image system upon considering attitude change in the high-speed boat. As to the division of hull surface, the portions protruded above the static water surface were cut off from among the panel data of boat CAD. Considering a high speed condition in which the water surface is completely separated at the transom section, the water level at the transom section was supposed to be at the same height as at the rear end of the hull. Blow-out intensity at the water surface was derived in such a way that a CAD panel of the rear end of the hull is searched and wave height agrees with the height of the transom in the Z direction. A resistance curve may be obtained easily by using a personal computer. 4 refs., 8 figs.

High-speed readout of high-Z pixel detectors with the LAMBDA detector

International Nuclear Information System (INIS)

Pennicard, D.; Smoljanin, S.; Sheviakov, I.; Xia, Q.; Rothkirch, A.; Yu, Y.; Struth, B.; Hirsemann, H.; Graafsma, H.

2014-01-01

High-frame-rate X-ray pixel detectors make it possible to perform time-resolved experiments at synchrotron beamlines, and to make better use of these sources by shortening experiment times. LAMBDA is a photon-counting hybrid pixel detector based on the Medipix3 chip, designed to combine a small pixel size of 55 μm, a large tileable module design, high speed, and compatibility with ''high-Z'' sensors for hard X-ray detection. This technical paper focuses on LAMBDA's high-speed-readout functionality, which allows a frame rate of 2000 frames per second with no deadtime between successive images. This takes advantage of the Medipix3 chip's ''continuous read-write'' function and highly parallelised readout. The readout electronics serialise this data and send it back to a server PC over two 10 Gigabit Ethernet links. The server PC controls the detector and receives, processes and stores the data using software designed for the Tango control system. As a demonstration of high-speed readout of a high-Z sensor, a GaAs LAMBDA detector was used to make a high-speed X-ray video of a computer fan

Imaging stability in force-feedback high-speed atomic force microscopy

International Nuclear Information System (INIS)

Kim, Byung I.; Boehm, Ryan D.

2013-01-01

We studied the stability of force-feedback high-speed atomic force microscopy (HSAFM) by imaging soft, hard, and biological sample surfaces at various applied forces. The HSAFM images showed sudden topographic variations of streaky fringes with a negative applied force when collected on a soft hydrocarbon film grown on a grating sample, whereas they showed stable topographic features with positive applied forces. The instability of HSAFM images with the negative applied force was explained by the transition between contact and noncontact regimes in the force–distance curve. When the grating surface was cleaned, and thus hydrophilic by removing the hydrocarbon film, enhanced imaging stability was observed at both positive and negative applied forces. The higher adhesive interaction between the tip and the surface explains the improved imaging stability. The effects of imaging rate on the imaging stability were tested on an even softer adhesive Escherichia coli biofilm deposited onto the grating structure. The biofilm and planktonic cell structures in HSAFM images were reproducible within the force deviation less than ∼0.5 nN at the imaging rate up to 0.2 s per frame, suggesting that the force-feedback HSAFM was stable for various imaging speeds in imaging softer adhesive biological samples. - Highlights: ► We investigated the imaging stability of force-feedback HSAFM. ► Stable–unstable imaging transitions rely on applied force and sample hydrophilicity. ► The stable–unstable transitions are found to be independent of imaging rate

High Speed Magnetostrictive MEMS Actuated Mirror Deflectors, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The main goal of this proposal is to develop high speed magnetostrictive and MEMS actuators for rapidly deflecting or deforming mirrors. High speed, light-weight,...

Variable load failure mechanism for high-speed load sensing electro-hydrostatic actuator pump of aircraft

Directory of Open Access Journals (Sweden)

Cun SHI

2018-05-01

Full Text Available This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator (LS-EHA. Focusing on the slipper/swashplate pair partial abrasion, which is considered as the dominant failure mode in the high-speed condition, slipper dynamic models are established. A forth sliding motion of the slipper on the swashplate surface is presented under the fact that the slipper center of mass will rotate around the center of piston ball when the swashplate angle is dynamically adjusted. Besides, extra inertial tilting moments will be produced for the slipper based on the theorem on translation of force, which will increase rapidly when LS-EHA pump operates under high-speed condition. Then, a dynamic lubricating model coupling with fluid film thickness field, temperature field and pressure field is proposed. The deformation effects caused by thermal deflection and hydrostatic pressure are considered. A numerical simulation model is established to validate the effectiveness and accuracy of the proposed model. Finally, based on the load spectrum of aircraft flight profile, the variable load conditions and the oil film characteristics are analyzed, and series of variable load rules of oil film thickness with variable speed/variable pressure/variable displacement are concluded. Keywords: Coupling lubrication model, Electro-Hydrostatic Actuator (EHA, High-speed pump, Partial abrasion, Slipper pair, Variable load

A modified time-of-flight method for precise determination of high speed ratios in molecular beams

Energy Technology Data Exchange (ETDEWEB)

Salvador Palau, A.; Eder, S. D., E-mail: sabrina.eder@uib.no; Kaltenbacher, T.; Samelin, B.; Holst, B. [Department of Physics and Technology, University of Bergen, Allégaten 55, 5007 Bergen (Norway); Bracco, G. [Department of Physics and Technology, University of Bergen, Allégaten 55, 5007 Bergen (Norway); CNR-IMEM, Department of Physics, University of Genova, V. Dodecaneso 33, 16146 Genova (Italy)

2016-02-15

Time-of-flight (TOF) is a standard experimental technique for determining, among others, the speed ratio S (velocity spread) of a molecular beam. The speed ratio is a measure for the monochromaticity of the beam and an accurate determination of S is crucial for various applications, for example, for characterising chromatic aberrations in focussing experiments related to helium microscopy or for precise measurements of surface phonons and surface structures in molecular beam scattering experiments. For both of these applications, it is desirable to have as high a speed ratio as possible. Molecular beam TOF measurements are typically performed by chopping the beam using a rotating chopper with one or more slit openings. The TOF spectra are evaluated using a standard deconvolution method. However, for higher speed ratios, this method is very sensitive to errors related to the determination of the slit width and the beam diameter. The exact sensitivity depends on the beam diameter, the number of slits, the chopper radius, and the chopper rotation frequency. We present a modified method suitable for the evaluation of TOF measurements of high speed ratio beams. The modified method is based on a systematic variation of the chopper convolution parameters so that a set of independent measurements that can be fitted with an appropriate function are obtained. We show that with this modified method, it is possible to reduce the error by typically one order of magnitude compared to the standard method.

High speed, self-acting shaft seal. [for use in turbine engines

Science.gov (United States)

Ludwig, L. P.; Hady, W. F. (Inventor)

1975-01-01

A high-speed, self-acting circumferential type shaft seal for use in turbine engines is disclosed. One or more conventional circumferential ring seals having a central aperture are mounted in a housing. In three of the four embodiments of the invention, a helical groove and one or more dam seals are cut in the inner cylindrical surface of the one or more ring seals. In a fourth embodiment, two or more lift pads are disposed in surface contact with the inner cylindrical surface of the seal rings. To the outside of the lift pads, two dam seals are cut in the inner cylindrical surface of two of the ring seals. In each of the embodiments, a net outward radial force was produced during rotation of the turbine causing the ring seals to lift out of contact with the turbine shaft to minimize wear of the ring seals.

Cadence® High High-Speed PCB Design Flow Workshop

CERN Document Server

2006-01-01

Last release of Cadence High-Speed PCB Design methodology (PE142) based on Concept-HDL schematic editor, Constraint Manager, SPECCTRAQuest signal integrity analysis tool and ALLEGRO layout associated with SPECCTRA auto router tools, is now enough developed and stable to be taken into account for high-speed board designs at CERN. The implementation of this methodology, build around the new Constraint Manager program, is essential when you have to develop a board having a lot of high-speed design rules such as terminated lines, large bus structures, maximum length, timing, crosstalk etc.. that could not be under control by traditional method. On more conventional designs, formal aspect of the methodology could avoid misunderstanding between hardware and ALLEGRO layout designers, minimizing prototype iteration, development time and price. The capability to keep trace of the original digital designer intents in schematic or board layout, loading formal constraints in EDMS, could also be considered for LHC electro...

High-speed LWR transients simulation for optimizing emergency response

International Nuclear Information System (INIS)

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

1984-01-01

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

Experiences with the hydraulic design of the high specific speed Francis turbine

International Nuclear Information System (INIS)

Obrovsky, J; Zouhar, J

2014-01-01

The high specific speed Francis turbine is still suitable alternative for refurbishment of older hydro power plants with lower heads and worse cavitation conditions. In the paper the design process of such kind of turbine together with the results comparison of homological model tests performed in hydraulic laboratory of ČKD Blansko Engineering is introduced. The turbine runner was designed using the optimization algorithm and considering the high specific speed hydraulic profile. It means that hydraulic profiles of the spiral case, the distributor and the draft tube were used from a Kaplan turbine. The optimization was done as the automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. The number of blades is shown as the parameter which changes the resulting specific speed of the turbine between n s =425 to 455 together with the cavitation characteristics. Minimizing of cavitation on the blade surface as well as on the inlet edge of the runner blade was taken into account during the design process. The results of CFD analyses as well as the model tests are mentioned in the paper

Experiences with the hydraulic design of the high specific speed Francis turbine

Science.gov (United States)

Obrovsky, J.; Zouhar, J.

2014-03-01

The high specific speed Francis turbine is still suitable alternative for refurbishment of older hydro power plants with lower heads and worse cavitation conditions. In the paper the design process of such kind of turbine together with the results comparison of homological model tests performed in hydraulic laboratory of ČKD Blansko Engineering is introduced. The turbine runner was designed using the optimization algorithm and considering the high specific speed hydraulic profile. It means that hydraulic profiles of the spiral case, the distributor and the draft tube were used from a Kaplan turbine. The optimization was done as the automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. The number of blades is shown as the parameter which changes the resulting specific speed of the turbine between ns=425 to 455 together with the cavitation characteristics. Minimizing of cavitation on the blade surface as well as on the inlet edge of the runner blade was taken into account during the design process. The results of CFD analyses as well as the model tests are mentioned in the paper.

Application of Mastic Asphalt Waterproofing Layer in High-Speed Railway Track in Cold Regions

Directory of Open Access Journals (Sweden)

Song Liu

2018-04-01

Full Text Available Freeze-thaw damage is a typical distress incurred in road and railway engineering in cold regions. Concrete waterproofing layer is commonly used in high-speed railway tracks to prevent the penetration of surface water, however, it cracks easily under thermal stress, especially in cold regions. Recently solutions have been proposed to increase the waterproofing layer’s cracking resistance by using asphalt layers. Nonetheless, the use of emulsified asphalt as well as dense-graded asphalt mixture were not effective enough. To improve the effectiveness, in this study, mastic asphalt was designed for application as the waterproofing layer on the subgrade surface of high-speed railway tracks in cold regions. The overall performance of mastic asphalt was preliminarily evaluated by laboratory tests, then a 200-m test section was constructed for field validation in northeastern China as part of a new high-speed railway line, and water content sensors were placed inside the subgrade to monitor the performance of the mastic asphalt waterproofing layer (MAWL. The subsequent field investigation and monitoring data during the two years operation showed that MAWL dramatically outperformed the conventional concrete waterproofing layer in terms of waterproof performance. Plenty of serious cracks were found in the conventional concrete waterproofing layer, but only a limited number of local cracks were observed in MAWL. As a result, MAWL keeps the water content of subgrade at a stable level. In addition, MAWL showed relatively high stability during the two years investigation period, and no obvious deterioration was observed in the test section.

Neoclassical transport coefficients for tokamaks with bean-shaped flux surfaces

International Nuclear Information System (INIS)

Chang, C.S.; Kaye, S.M.

1990-11-01

Simple analytic representations of the neoclassical transport coefficients for indented flux surfaces are presented. It is shown that a transport coefficient for an indented flux surface can be expressed in terms of a linear combination of the previously known transport coefficients for two nonindented flux surfaces. Numerical calculations based on actual equilibria from the PBX-M tokamak indicate that, even for modestly indented flux surfaces, the ion neoclassical thermal transport can be over a factor of two smaller than in a circular plasma with the same midplane radius or with the equivalent areas. 6 refs., 5 figs., 1 tab

Low-Speed Cooperative Car-Following Fuzzy Controller for Cybernetic Transport Systems

OpenAIRE

Milanés , Vicente; Marouf , Mohamed; Pérez Rastelli , Joshué; Gonzalez Bautista , David; Nashashibi , Fawzi

2014-01-01

International audience; — This paper describes the development of a Coop-erative Adaptive Cruise Control (CACC) for the future urban transportation system at low-speed. The control algorithm was evaluated using two Cybecars as prototype vehicles. A longitu-dinal response model for the vehicles was developed to design the CACC system. The control algorithm was implemented on a fuzzy logic-based controller that has been tuned to minimize a cost function in order to get a trade-off between a pro...

Taphonomic evidence for high-speed adapted fins in thunniform ichthyosaurs

Science.gov (United States)

Lingham-Soliar, Theagarten; Plodowski, Gerhard

2007-01-01

Ichthyosaurs have been compared with the fast-swimming thunniform groups of marine vertebrates, tuna, lamnid sharks, and dolphins, based on similarity of shape of the body and locomotory organs. In addition to shape, high-tensile stiffness of the control surfaces has been shown to be essential in maximizing hydrodynamic efficiency in extant thunniform swimmers. To date, there has been no evidence of a stiffening support system for the dorsal fin and dorsal lobe of the caudal fin in ichthyosaurs, the sole stiffening structure of the ventral lobe being an extension of the vertebral column along its leading edge. Stenopterygius SMF 457 is arguably the best soft-tissue preserved ichthyosaur specimen known. Here, we examine soft-tissue preservation in this specimen in the control surfaces and provide the first evidence of a complex architecture of stiff fibers in the dorsal and caudal fins. We find by comparisons and by analogy that these fibers provided a remarkable mechanism for high tensile stiffness and efficiency of the locomotory organs virtually identical to that of the great white shark, Carcharodon carcharias. It is the first mechanostructural study of the control surfaces of a Jurassic ichthyosaur that adds essential evidence in support of the view that these forms were high-speed thunniform swimmers.

Simulation of High-Speed Droplet Impact Against Dry Substrates with Partial Velocity Slip

Science.gov (United States)

Kondo, Tomoki; Ando, Keita

2017-11-01

High-speed droplet impact can be used to clean substrates such as silicon wafers. Radially spreading shear flow after the impact may allow for mechanically removing contaminant particles at substrate surfaces. Since it is a big challenge to experimentally explore such complicated flow that exhibits contact line motion and water hammer, its flow feature is not well understood. Here, we aim to numerically evaluate shear flow caused by the impact of a spherical water droplet (of submillimeter sizes) at high speed (up to 50 m/s) against a dry rigid wall. We model the flow based on compressible Navier-Stokes equations with Stokes' hypothesis and solve them by a high-order-accurate finite volume method equipped with shock and interface capturing. To treat the motion of a contact line between the three phases (the droplet, the rigid wall, and the ambient air) in a robust manner, we permit velocity slip at the wall with Navier's model, for wall slip is known to come into play under steep velocity gradients that can arise from high-speed droplet impact. In our presentation, we will examine radially spreading flow after the droplet impact and the resulting wall shear stress generation from the simulation. This work was supported by JSPS KAKENHI Grant Number JP17J02211.

Real-time nanofabrication with high-speed atomic force microscopy

International Nuclear Information System (INIS)

Vicary, J A; Miles, M J

2009-01-01

The ability to follow nanoscale processes in real-time has obvious benefits for the future of material science. In particular, the ability to evaluate the success of fabrication processes in situ would be an advantage for many in the semiconductor industry. We report on the application of a previously described high-speed atomic force microscope (AFM) for nanofabrication. The specific fabrication method presented here concerns the modification of a silicon surface by locally oxidizing the region in the vicinity of the AFM tip. Oxide features were fabricated during imaging, with relative tip-sample velocities of up to 10 cm s -1 , and with a data capture rate of 15 fps.

Design of high-speed turnouts and crossings

Science.gov (United States)

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.

High speed ink aggregates are ejected from tattoos during Q-switched Nd:YAG laser treatments.

Science.gov (United States)

Murphy, Michael J

2018-03-25

Dark material has been observed embedded within glass slides following Q-switched Nd:YAG laser treatment of tattoos. It appears that these fragments are ejected at high speed from the skin during the treatment. Light microscopic analysis of the slides reveals aggregates of dark fragmented material, presumably tattoo ink, with evidence of fractured/melted glass. Photomicrographs reveal that the sizes of these aggregates are in the range 12 μm to 0.5 mm. Tattoo ink fragments were clearly observed on the surface and embedded within glass slides. Surface aggregates were observed as a fine dust and were easily washed off while deeper fragments remained in situ. The embedded fragments were not visible to the unaided eye. Some fragments appeared to have melted yielding an "insect-like" appearance. These were found to be located between approximately 0.2 and 1 mm deep in the glass. Given the particle masses and kinetic energies attained by some of these aggregates their velocities, when leaving the skin, may be hundreds to thousands of metres per second. However, the masses of the aggregates are minuscule meaning that laser operators may be subjected to these high-speed aggregates without their knowledge. These high-speed fragments of ink may pose a contamination risk to laser operators. Lasers Surg. Med. 9999:1-7, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Research on the tool holder mode in high speed machining

Science.gov (United States)

Zhenyu, Zhao; Yongquan, Zhou; Houming, Zhou; Xiaomei, Xu; Haibin, Xiao

2018-03-01

High speed machining technology can improve the processing efficiency and precision, but also reduce the processing cost. Therefore, the technology is widely regarded in the industry. With the extensive application of high-speed machining technology, high-speed tool system has higher and higher requirements on the tool chuck. At present, in high speed precision machining, several new kinds of clip heads are as long as there are heat shrinkage tool-holder, high-precision spring chuck, hydraulic tool-holder, and the three-rib deformation chuck. Among them, the heat shrinkage tool-holder has the advantages of high precision, high clamping force, high bending rigidity and dynamic balance, etc., which are widely used. Therefore, it is of great significance to research the new requirements of the machining tool system. In order to adapt to the requirement of high speed machining precision machining technology, this paper expounds the common tool holder technology of high precision machining, and proposes how to select correctly tool clamping system in practice. The characteristics and existing problems are analyzed in the tool clamping system.

Three-dimensional optical reconstruction of vocal fold kinematics using high-speed video with a laser projection system

Science.gov (United States)

Luegmair, Georg; Mehta, Daryush D.; Kobler, James B.; Döllinger, Michael

2015-01-01

Vocal fold kinematics and its interaction with aerodynamic characteristics play a primary role in acoustic sound production of the human voice. Investigating the temporal details of these kinematics using high-speed videoendoscopic imaging techniques has proven challenging in part due to the limitations of quantifying complex vocal fold vibratory behavior using only two spatial dimensions. Thus, we propose an optical method of reconstructing the superior vocal fold surface in three spatial dimensions using a high-speed video camera and laser projection system. Using stereo-triangulation principles, we extend the camera-laser projector method and present an efficient image processing workflow to generate the three-dimensional vocal fold surfaces during phonation captured at 4000 frames per second. Initial results are provided for airflow-driven vibration of an ex vivo vocal fold model in which at least 75% of visible laser points contributed to the reconstructed surface. The method captures the vertical motion of the vocal folds at a high accuracy to allow for the computation of three-dimensional mucosal wave features such as vibratory amplitude, velocity, and asymmetry. PMID:26087485

High-speed photodetectors in optical communication system

Science.gov (United States)

Zhao, Zeping; Liu, Jianguo; Liu, Yu; Zhu, Ninghua

2017-12-01

This paper presents a review and discussion for high-speed photodetectors and their applications on optical communications and microwave photonics. A detailed and comprehensive demonstration of high-speed photodetectors from development history, research hotspots to packaging technologies is provided to the best of our knowledge. A few typical applications based on photodetectors are also illustrated, such as free-space optical communications, radio over fiber and millimeter terahertz signal generation systems. Project supported by the Preeminence Youth Fund of China (No. 61625504).

Development of high sensitivity and high speed large size blank inspection system LBIS

Science.gov (United States)

Ohara, Shinobu; Yoshida, Akinori; Hirai, Mitsuo; Kato, Takenori; Moriizumi, Koichi; Kusunose, Haruhiko

2017-07-01

The production of high-resolution flat panel displays (FPDs) for mobile phones today requires the use of high-quality large-size photomasks (LSPMs). Organic light emitting diode (OLED) displays use several transistors on each pixel for precise current control and, as such, the mask patterns for OLED displays are denser and finer than the patterns for the previous generation displays throughout the entire mask surface. It is therefore strongly demanded that mask patterns be produced with high fidelity and free of defect. To enable the production of a high quality LSPM in a short lead time, the manufacturers need a high-sensitivity high-speed mask blank inspection system that meets the requirement of advanced LSPMs. Lasertec has developed a large-size blank inspection system called LBIS, which achieves high sensitivity based on a laser-scattering technique. LBIS employs a high power laser as its inspection light source. LBIS's delivery optics, including a scanner and F-Theta scan lens, focus the light from the source linearly on the surface of the blank. Its specially-designed optics collect the light scattered by particles and defects generated during the manufacturing process, such as scratches, on the surface and guide it to photo multiplier tubes (PMTs) with high efficiency. Multiple PMTs are used on LBIS for the stable detection of scattered light, which may be distributed at various angles due to irregular shapes of defects. LBIS captures 0.3mμ PSL at a detection rate of over 99.5% with uniform sensitivity. Its inspection time is 20 minutes for a G8 blank and 35 minutes for G10. The differential interference contrast (DIC) microscope on the inspection head of LBIS captures high-contrast review images after inspection. The images are classified automatically.

Analysis and topology optimization design of high-speed driving spindle

Science.gov (United States)

Wang, Zhilin; Yang, Hai

2018-04-01

The three-dimensional model of high-speed driving spindle is established by using SOLIDWORKS. The model is imported through the interface of ABAQUS, A finite element analysis model of high-speed driving spindle was established by using spring element to simulate bearing boundary condition. High-speed driving spindle for the static analysis, the spindle of the stress, strain and displacement nephogram, and on the basis of the results of the analysis on spindle for topology optimization, completed the lightweight design of high-speed driving spindle. The design scheme provides guidance for the design of axial parts of similar structures.

75 FR 25927 - Vehicle/Track Interaction Safety Standards; High-Speed and High Cant Deficiency Operations

Science.gov (United States)

2010-05-10

... Transporte;* Sheet Metal Workers International Association (SMWIA); Tourist Railway Association, Inc... over their intended service routes using instrumented wheelsets to directly measure forces between the... Carbody Acceleration Events During route testing of the MARC-III multi-level car at speeds to 125 m.p.h...

HIGH SPEED RAILWAY LINES – FUTURE PART OF CZECH RAILWAY NETWORK?

Directory of Open Access Journals (Sweden)

Lukáš Týfa

2017-08-01

Full Text Available The paper first describes high speed rail generally and explains the relationship between high speed and conventional railway networks (according to the vehicle types in operation on the network. The core of the paper is comprised of the methodology for choosing the best route for a railway line and its application to the high speed railway connection Praha – Brno. The Algorithm used assumes the existence of more route proposals, which could be different in terms of the operational conception, line routing or types of vehicles used. The optimal variant is the one with the lowest daily cost, which includes infrastructure and vehicle costs; investment and operational costs. The results from applying this model confirmed the assumption, that a dedicated high speed railway line, only for high speed trains, has the same or lower investment costs than a line for both high speed and conventional trains. Furthermore, a dedicated high line also has a lower cost for infrastructure maintenance but a higher cost for buying high speed multiple units.

Proposal of a high rigidity and high speed rotating mechanism using a new concept hydrodynamic bearing in X-ray tube for high speed computed tomography

International Nuclear Information System (INIS)

Hattori, Hitoshi; Fukushima, Harunobu; Yoshii, Yasuo; Nakamuta, Hironori; Iwase, Mitsuo; Kitade, Koichi

2009-01-01

In this paper, a high rigidity and high speed rotating mechanism using a new concept hydrodynamic bearing in X-ray tube for high speed computed tomography is proposed. In order to obtain both the stability and the high load carrying capacity, the hydrodynamic bearing lubricated by liquid metal (Gallium alloy), named as the hybrid hydrodynamic bearing generates the lubricating film by wedge effect on the plane region between the spiral grooves under high loading condition. The parallelism between the bearing and the rotating body can be secured by optimizing the rigidity distribution of stationary shaft in the proposed rotating mechanism. By carrying out the fundamental design by numerical analyses, it has been made clear that the hybrid hydrodynamic bearing and the rotating mechanism are suitable for the X-ray tube used in the CT with ever-increasingly scanning speed. (author)

Experimental investigation by laser ultrasonics for high speed train axle diagnostics.

Science.gov (United States)

Cavuto, A; Martarelli, M; Pandarese, G; Revel, G M; Tomasini, E P

2015-01-01

The present paper demonstrates the applicability of a laser-ultrasonic procedure to improve the performances of train axle ultrasonic inspection. The method exploits an air-coupled ultrasonic probe that detects the ultrasonic waves generated by a high-power pulsed laser. As a result, the measurement chain is completely non-contact, from generation to detection, this making it possible to considerably speed up inspection time and make the set-up more flexible. The main advantage of the technique developed is that it works in thermo-elastic regime and it therefore can be considered as a non-destructive method. The laser-ultrasonic procedure investigated has been applied for the inspection of a real high speed train axle provided by the Italian railway company (Trenitalia), on which typical fatigue defects have been expressly created according to standard specifications. A dedicated test bench has been developed so as to rotate the axle with the angle control and to speed up the inspection of the axle surface. The laser-ultrasonic procedure proposed can be automated and is potentially suitable for regular inspection of train axles. The main achievements of the activity described in this paper are: – the study of the effective applicability of laser-ultrasonics for the diagnostic of train hollow axles with variable sections by means of a numerical FE model, – the carrying out of an automated experiment on a real train axle, – the analysis of the sensitivity to experimental parameters, like laser source – receiving probe distance and receiving probe angular position, – the demonstration that the technique is suitable for the detection of surface defects purposely created on the train axle. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of Fabry-Perot velocimeter to high-speed experiments

International Nuclear Information System (INIS)

Chaw, H.H.; McMillan, C.F.; Osher, J.E.

1988-01-01

The Fabry-Perot (F-P) velocimeter is a useful instrument for measuring the velocity of objects at speeds ranging from fractions of a kilometer per second to a few tens of kilometers per second and up. Because of its immunity to electromagnetic interference and its velocity resolution, it has become the prime diagnostic tool in our electric-gun facility. Examples of its application to high speed experiments are discussed, including: electric-gun flyer studies, spallation of materials under high-speed impact, momentum-transfer studies, pressure pulse created by high-velocity impact, and detonation-wave studies in high-explosive experiments

Analysis of Metal Flow Behavior and Residual Stress Formation of Complex Functional Profiles under High-Speed Cold Roll-Beating

Directory of Open Access Journals (Sweden)

Fengkui Cui

2018-01-01

Full Text Available To obtain a good surface layer performance of the complex functional profile during the high-speed cold roll-beating forming process, this paper analyzed the metal plastic flow and residual stress-formed mechanism by using a theoretical model of the metal flow and residual stress generation. By using simulation software, the cold roll-beating forming process of a spline shaft was simulated and analyzed. The metal flow and residual stress formation law in the motion were researched. In a practical experiment, the changes in the grains in the spline tooth profile section and the residual stress distribution on the tooth profile were studied. A microcorrespondence relationship was established between the metal plastic flow and the residual stress generation. The conclusions indicate that the rate at which the metal flow decreases changes gradually at different metal layers. The residual stress value is directly related to the plastic flow difference. As the roll-beating speed increases, the uneven degree of plastic deformation at the workpiece surface increases, and the residual stress in the tooth profile is generally greater. At the same roll-beating speed, the rate change trend of the metal flow decreases gradually from the surface to the inner layer and from the dedendum to the addendum. The residual stress distribution on the surface of the tooth profile decreases from the dedendum to the addendum. These findings provide a basis and guidance for the controlled use of residual stress, obtaining better surface layer quality in the high-speed cold roll-beating process of the complex functional profile.

High-speed adaptive contact-mode atomic force microscopy imaging with near-minimum-force

Energy Technology Data Exchange (ETDEWEB)

Ren, Juan; Zou, Qingze, E-mail: qzzou@rci.rutgers.edu [Department of Mechanical and Aerospace Engineering, Rutgers University, 98 Brett Rd, Piscataway, New Jersey 08854 (United States)

2014-07-15

In this paper, an adaptive contact-mode imaging approach is proposed to replace the traditional contact-mode imaging by addressing the major concerns in both the speed and the force exerted to the sample. The speed of the traditional contact-mode imaging is largely limited by the need to maintain precision tracking of the sample topography over the entire imaged sample surface, while large image distortion and excessive probe-sample interaction force occur during high-speed imaging. In this work, first, the image distortion caused by the topography tracking error is accounted for in the topography quantification. Second, the quantified sample topography is utilized in a gradient-based optimization method to adjust the cantilever deflection set-point for each scanline closely around the minimal level needed for maintaining stable probe-sample contact, and a data-driven iterative feedforward control that utilizes a prediction of the next-line topography is integrated to the topography feeedback loop to enhance the sample topography tracking. The proposed approach is demonstrated and evaluated through imaging a calibration sample of square pitches at both high speeds (e.g., scan rate of 75 Hz and 130 Hz) and large sizes (e.g., scan size of 30 μm and 80 μm). The experimental results show that compared to the traditional constant-force contact-mode imaging, the imaging speed can be increased by over 30 folds (with the scanning speed at 13 mm/s), and the probe-sample interaction force can be reduced by more than 15% while maintaining the same image quality.

High-speed adaptive contact-mode atomic force microscopy imaging with near-minimum-force

International Nuclear Information System (INIS)

Ren, Juan; Zou, Qingze

2014-01-01

In this paper, an adaptive contact-mode imaging approach is proposed to replace the traditional contact-mode imaging by addressing the major concerns in both the speed and the force exerted to the sample. The speed of the traditional contact-mode imaging is largely limited by the need to maintain precision tracking of the sample topography over the entire imaged sample surface, while large image distortion and excessive probe-sample interaction force occur during high-speed imaging. In this work, first, the image distortion caused by the topography tracking error is accounted for in the topography quantification. Second, the quantified sample topography is utilized in a gradient-based optimization method to adjust the cantilever deflection set-point for each scanline closely around the minimal level needed for maintaining stable probe-sample contact, and a data-driven iterative feedforward control that utilizes a prediction of the next-line topography is integrated to the topography feeedback loop to enhance the sample topography tracking. The proposed approach is demonstrated and evaluated through imaging a calibration sample of square pitches at both high speeds (e.g., scan rate of 75 Hz and 130 Hz) and large sizes (e.g., scan size of 30 μm and 80 μm). The experimental results show that compared to the traditional constant-force contact-mode imaging, the imaging speed can be increased by over 30 folds (with the scanning speed at 13 mm/s), and the probe-sample interaction force can be reduced by more than 15% while maintaining the same image quality

Trans and surface membrane bound zervamicin IIB: 13C-MAOSS-NMR at high spinning speed

International Nuclear Information System (INIS)

Raap, J.; Hollander, J.; Ovchinnikova, T. V.; Swischeva, N. V.; Skladnev, D.; Kiihne, S.

2006-01-01

Interactions between 15 N-labelled peptides or proteins and lipids can be investigated using membranes aligned on a thin polymer film, which is rolled into a cylinder and inserted into the MAS-NMR rotor. This can be spun at high speed, which is often useful at high field strengths. Unfortunately, substrate films like commercially available polycarbonate or PEEK produce severe overlap with peptide and protein signals in 13 C-MAOSS NMR spectra. We show that a simple house hold foil support allows clear observation of the carbonyl, aromatic and C α signals of peptides and proteins as well as the ester carbonyl and choline signals of phosphocholine lipids. The utility of the new substrate is validated in applications to the membrane active peptide zervamicin IIB. The stability and macroscopic ordering of thin PC10 bilayers was compared with that of thicker POPC bilayers, both supported on the household foil. Sidebands in the 31 P-spectra showed a high degree of alignment of both the supported POPC and PC10 lipid molecules. Compared with POPC, the PC10 lipids are slightly more disordered, most likely due to the increased mobilities of the shorter lipid molecules. This mobility prevents PC10 from forming stable vesicles for MAS studies. The 13 C-peptide peaks were selectively detected in a 13 C-detected 1 H-spin diffusion experiment. Qualitative analysis of build-up curves obtained for different mixing times allowed the transmembrane peptide in PC10 to be distinguished from the surface bound topology in POPC. The 13 C-MAOSS results thus independently confirms previous findings from 15 N spectroscopy [Bechinger, B., Skladnev, D.A., Ogrel, A., Li, X., Rogozhkina, E.V., Ovchinnikova, T.V., O'Neil, J.D.J. and Raap, J. (2001) Biochemistry, 40, 9428-9437]. In summary, application of house hold foil opens the possibility of measuring high resolution 13 C-NMR spectra of peptides and proteins in well ordered membranes, which are required to determine the secondary and

Application of polarization in high speed, high contrast inspection

Science.gov (United States)

Novak, Matthew J.

2017-08-01

Industrial optical inspection often requires high speed and high throughput of materials. Engineers use a variety of techniques to handle these inspection needs. Some examples include line scan cameras, high speed multi-spectral and laser-based systems. High-volume manufacturing presents different challenges for inspection engineers. For example, manufacturers produce some components in quantities of millions per month, per week or even per day. Quality control of so many parts requires creativity to achieve the measurement needs. At times, traditional vision systems lack the contrast to provide the data required. In this paper, we show how dynamic polarization imaging captures high contrast images. These images are useful for engineers to perform inspection tasks in some cases where optical contrast is low. We will cover basic theory of polarization. We show how to exploit polarization as a contrast enhancement technique. We also show results of modeling for a polarization inspection application. Specifically, we explore polarization techniques for inspection of adhesives on glass.

High speed network sampling

OpenAIRE

Rindalsholt, Ole Arild

2005-01-01

Master i nettverks- og systemadministrasjon Classical Sampling methods play an important role in the current practice of Internet measurement. With today’s high speed networks, routers cannot manage to generate complete Netflow data for every packet. They have to perform restricted sampling. This thesis summarizes some of the most important sampling schemes and their applications before diving into an analysis on the effect of sampling Netflow records.

High Speed On-Wafer Characterization Laboratory

Data.gov (United States)

Federal Laboratory Consortium — At the High Speed On-Wafer Characterization Laboratory, researchers characterize and model devices operating at terahertz (THz) and millimeter-wave frequencies. The...

HIGH-SPEED RAILWAY AND TOURISM: IS THERE AN IMPACT ON INTERMEDIATE CITIES? EVIDENCE FROM TWO CASE STUDIES IN CASTILLA-LA MANCHA (SPAIN

Directory of Open Access Journals (Sweden)

Carmen VÁZQUEZ VARELA

2016-12-01

Full Text Available The expectations of cities served by High Speed Rail are numerous. Improvements in a destination’s accessibility could lead to an increase in transport demand and the revitalization of urban and business tourism. However, High Speed Rail services do not automatically affect the choice of destination even if they improve accessibility. Even so, they can improve visitation rates when tourist amenities are located near High Speed Rail stations becoming therefore easily accessible. The development of tourism is also influenced by the collective strategies of local stakeholders. Larger cities also appear able to leverage higher tourist volumes from the construction of High Speed Rail and most analyses to date have focused upon them. Thus we focus here on how the arrival of High Speed Rail services has impacted tourism on medium sized cities. Using a diachronic study of different socio-economic variables and tourist features, this article analyses the impact that the new rail infrastructure can have on tourism in two selected cases in Spain: Cuenca and Toledo.

High-speed nonvolatile CMOS/MNOS RAM

International Nuclear Information System (INIS)

Derbenwick, G.F.; Dodson, W.D.; Sokel, R.J.

1979-01-01

A bulk silicon technology for a high-speed static CMOS/MNOS RAM has been developed. Radiation-hardened, high voltage CMOS circuits have been fabricated for the memory array driving circuits and the enhancement-mode p-channel MNOS memory transistors have been fabricated using a native tunneling oxide with a 45 nm CVD Si 3 N 4 insulator deposited at 750 0 C. Read cycle times less than 350 ns and write cycle times of 1 μs are projected for the final 1Kx1 design. The CMOS circuits provide adequate speed for the write and read cycles and minimize the standby power dissipation. Retention times well in excess of 30 min are projected

High-speed cryptography and cryptanalysis

NARCIS (Netherlands)

Schwabe, P.

2011-01-01

Modern digital communication relies heavily on cryptographic protection to ensure data integrity and privacy. In order to deploy state-of-the art cryptographic primitives and protocols in real-world scenarios, one needs to highly optimize software for both speed and security. This requires careful

Advancing high-speed rail policy in the United States.

Science.gov (United States)

2012-06-01

This report builds on a review of international experience with high-speed rail projects to develop recommendations for a High-speed rail policy framework for the United States. The international review looked at the experience of Korea, Taiwan, Chin...

Electron transport due to inhomogeneous broadening and its potential impact on modulation speed in p-doped quantum dot lasers

International Nuclear Information System (INIS)

Deppe, D G; Freisem, S; Huang, H; Lipson, S

2005-01-01

Data are first presented on spontaneous and laser emission of p-doped and undoped quantum dot (QD) heterostructures to characterize the increase in optical gain in p-type modulation doped QD lasers. Because the increase in gain due to p-doping should also increase the differential gain, but does not greatly increase the modulation speed in present p-doped QD lasers, we further examine nonequilibrium electron transport effects in p-doped active material that may still limit the modulation speed. Electron transport through the dot wetting layer caused by the nonlasing QDs of the active ensemble is shown to be capable of substantially reducing the modulation speed, independent of the differential gain. This nonequilibrium limitation can be eliminated by reducing the inhomogeneous broadening in the QD ensemble

Assessment of rural soundscapes with high-speed train noise.

Science.gov (United States)

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. © 2013.

Compact system for high-speed velocimetry using heterodyne techniques

International Nuclear Information System (INIS)

Strand, O. T.; Goosman, D. R.; Martinez, C.; Whitworth, T. L.; Kuhlow, W. W.

2006-01-01

We have built a high-speed velocimeter that has proven to be compact, simple to operate, and fairly inexpensive. This diagnostic is assembled using off-the-shelf components developed for the telecommunications industry. The main components are fiber lasers, high-bandwidth high-sample-rate digitizers, and fiber optic circulators. The laser is a 2 W cw fiber laser operating at 1550 nm. The digitizers have 8 GHz bandwidth and can digitize four channels simultaneously at 20 GS/s. The maximum velocity of this system is ∼5000 m/s and is limited by the bandwidth of the electrical components. For most applications, the recorded beat frequency is analyzed using Fourier transform methods, which determine the time response of the final velocity time history. Using the Fourier transform method of analysis allows multiple velocities to be observed simultaneously. We have obtained high-quality data on many experiments such as explosively driven surfaces and gas gun assemblies

High-speed imaging of explosive eruptions: applications and perspectives

Science.gov (United States)

Taddeucci, Jacopo; Scarlato, Piergiorgio; Gaudin, Damien; Capponi, Antonio; Alatorre-Ibarguengoitia, Miguel-Angel; Moroni, Monica

2013-04-01

Explosive eruptions, being by definition highly dynamic over short time scales, necessarily call for observational systems capable of relatively high sampling rates. "Traditional" tools, like as seismic and acoustic networks, have recently been joined by Doppler radar and electric sensors. Recent developments in high-speed camera systems now allow direct visual information of eruptions to be obtained with a spatial and temporal resolution suitable for the analysis of several key eruption processes. Here we summarize the methods employed to gather and process high-speed videos of explosive eruptions, and provide an overview of the several applications of these new type of data in understanding different aspects of explosive volcanism. Our most recent set up for high-speed imaging of explosive eruptions (FAMoUS - FAst, MUltiparametric Set-up,) includes: 1) a monochrome high speed camera, capable of 500 frames per second (fps) at high-definition (1280x1024 pixel) resolution and up to 200000 fps at reduced resolution; 2) a thermal camera capable of 50-200 fps at 480-120x640 pixel resolution; and 3) two acoustic to infrasonic sensors. All instruments are time-synchronized via a data logging system, a hand- or software-operated trigger, and via GPS, allowing signals from other instruments or networks to be directly recorded by the same logging unit or to be readily synchronized for comparison. FAMoUS weights less than 20 kg, easily fits into four, hand-luggage-sized backpacks, and can be deployed in less than 20' (and removed in less than 2', if needed). So far, explosive eruptions have been recorded in high-speed at several active volcanoes, including Fuego and Santiaguito (Guatemala), Stromboli (Italy), Yasur (Vanuatu), and Eyjafiallajokull (Iceland). Image processing and analysis from these eruptions helped illuminate several eruptive processes, including: 1) Pyroclasts ejection. High-speed videos reveal multiple, discrete ejection pulses within a single Strombolian

Connecting meteorology to surface transport in aeolian landscapes: Peering into the boundary layer with Doppler lidar

Science.gov (United States)

Gunn, A.; Jerolmack, D. J.; Edmonds, D. A.; Ewing, R. C.; Wanker, M.; David, S. R.

2017-12-01

Aolian sand dunes grow to 100s or 1000s of meters in wavelength by sand saltation, which also produces dust plumes that feed cloud formation and may spread around the world. The relations among sediment transport, landscape dynamics and wind are typically observed at the limiting ends of the relevant range: highly resolved and localized ground observations of turbulence and relevant fluxes; or regional and synoptic-scale meteorology and satellite imagery. Between the geostrophic winds aloft and shearing stress on the Earth's surface is the boundary layer, whose stability and structure determines how momentum is transferred and ultimately entrains sediment. Although the literature on atmospheric boundary layer flows is mature, this understanding is rarely applied to aeolian landscape dynamics. Moreover, there are few vertically and time-resolved datasets of atmospheric boundary layer flows in desert sand seas, where buoyancy effects are most pronounced. Here we employ a ground-based upward-looking doppler lidar to examine atmospheric boundary layer flow at the upwind margin of the White Sands (New Mexico) dune field, providing continuous 3D wind velocity data from the surface to 300-m aloft over 70 days of the characteristically windy spring season. Data show highly resolved daily cyles of convective instabilty due to daytime heating and stable stratification due to nightime cooling which act to enhance or depress, respectively, the surface wind stresses for a given free-stream velocity. Our data implicate convective instability in driving strong saltation and dust emission, because enhanced mixing flattens the vertical velocity profile (raising surface wind speed) while upward advection helps to deliver dust to the high atmosphere. We also find evidence for Ekman spiralling, with a magnitude that depends on atmospheric stability. This spiralling gives rise to a deflection in the direction between geostrophic and surface winds, that is significant for the

Cost-Benefit Analysis of High-Speed Rail Link between Hong Kong and Mainland China

Directory of Open Access Journals (Sweden)

R. Tao

2011-07-01

Full Text Available The Legislative Council in Hong Kong has approved a funding of USD$8.60 billion to build the high-speed rail (HSR line linking mainland China. HSR is a break-through technology that allows trains running at a speed over 250 km per hour. The most controversial part of the HSR investment is whether its cost could be compensated by the social benefits. In this study, a cost-benefit analysis of the Hong Kong to mainland HSR (HKM-HSR line is carried out. First, all the direct and indirect costs, and social benefits are defined; then, monetary equivalents are assigned to these elements; third, all the future values are discounted into present values and aggregated. The results show that the project has a positive net present value (NPV up to USD$2,068.49 million, which proves that the investment is worth. In addition, other transport alternatives, i.e. the existing roadway and conventional railway, are examined and compared with HKM-HSR, which unveils that HSR has the largest positive NPV among these three passenger transportation modes because of its excellent performance in ticket revenue, travel time savings and safety improvement.

Clinical diagnostic of pleural effusions using a high-speed viscosity measurement method

Science.gov (United States)

Hurth, Cedric; Klein, Katherine; van Nimwegen, Lena; Korn, Ronald; Vijayaraghavan, Krishnaswami; Zenhausern, Frederic

2011-08-01

We present a novel bio-analytical method to discriminate between transudative and exudative pleural effusions based on a high-speed video analysis of a solid glass sphere impacting a liquid. Since the result depends on the solution viscosity, it can ultimately replace the battery of biochemical assays currently used. We present results obtained on a series of 7 pleural effusions obtained from consenting patients by analyzing both the splash observed after the glass impactor hits the liquid surface, and in a configuration reminiscent of the drop ball viscometer with added sensitivity and throughput provided by the high-speed camera. The results demonstrate distinction between the pleural effusions and good correlation with the fluid chemistry analysis to accurately differentiate exudates and transudates for clinical purpose. The exudative effusions display a viscosity around 1.39 ± 0.08 cP whereas the transudative effusion was measured at 0.89 ± 0.09 cP, in good agreement with previous reports.

High-speed pellet injection with a two-stage pneumatic gun

International Nuclear Information System (INIS)

Reggiori, A.; Carlevaro, R.; Riva, G.; Daminelli, G.B.; Scaramuzzi, F.; Frattolillo, A.; Martinis, L.; Cardoni, P.; Mori, L.

1988-01-01

The injection of pellets of frozen hydrogen isotopes into fusion plasmas is envisioned as a fueling technique for future fusion reactors. Research is underway to obtain high injection speeds for solid H 2 and D 2 pellets. The optimization of a two-stage light gas gun is being pursued by the Milano group; the search for a convenient method of creating pellets with good mechanical properties and a secure attachment to the cold surface on which they are formed is carried out in Frascati. Velocities >2000 m/s have been obtained, but reproducibility is not yet satisfactory

Plasma-Assisted Chemistry in High-Speed Flow

International Nuclear Information System (INIS)

Leonov, Sergey B.; Yarantsev, Dmitry A.; Napartovich, Anatoly P.; Kochetov, Igor V.

2007-01-01

Fundamental problems related to the high-speed combustion are analyzed. The result of plasma-chemical modeling is presented as a motivation of experimental activity. Numerical simulations of the effect of uniform non-equilibrium discharge on the premixed hydrogen and ethylene-air mixture in supersonic flow demonstrate an advantage of such a technique over a heating. Experimental results on multi-electrode non-uniform discharge maintenance behind wallstep and in cavity of supersonic flow are presented. The model test on hydrogen and ethylene ignition is demonstrated at direct fuel injection to low-temperature high-speed airflow

Thermomechanical simulations and experimental validation for high speed incremental forming

Science.gov (United States)

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.

High Speed Photomicrography

Science.gov (United States)

Hyzer, William G.

1983-03-01

One of the most challenging areas in applying high-speed photography and videography in the plant and laboratory is in the recording of rapid events at macro and microscopic scales. Depth of field, exposure efficiency, working distance, and required exposure time are all reduced as optical magnification is increased, which severely taxes the skill and ingenuity of workers interested in recording any fast moving phenomena through the microscope or with magnifying lenses. This paper defines the problems inherent in photographing within macro and microscopic ranges and offers a systematic approach to optimizing the selection of equipment and choice of applicable techniques.

Lunar magma transport phenomena

Science.gov (United States)

Spera, Frank J.

1992-01-01

An outline of magma transport theory relevant to the evolution of a possible Lunar Magma Ocean and the origin and transport history of the later phase of mare basaltic volcanism is presented. A simple model is proposed to evaluate the extent of fractionation as magma traverses the cold lunar lithosphere. If Apollo green glasses are primitive and have not undergone significant fractionation en route to the surface, then mean ascent rates of 10 m/s and cracks of widths greater than 40 m are indicated. Lunar tephra and vesiculated basalts suggest that a volatile component plays a role in eruption dynamics. The predominant vapor species appear to be CO CO2, and COS. Near the lunar surface, the vapor fraction expands enormously and vapor internal energy is converted to mixture kinetic energy with the concomitant high-speed ejection of vapor and pyroclasts to form lunary fire fountain deposits such as the Apollo 17 orange and black glasses and Apollo 15 green glass.

The effect of three surface conditions, speed and running experience on vertical acceleration of the tibia during running.

Science.gov (United States)

Boey, Hannelore; Aeles, Jeroen; Schütte, Kurt; Vanwanseele, Benedicte

2017-06-01

Research has focused on parameters that are associated with injury risk, e.g. vertical acceleration. These parameters can be influenced by running on different surfaces or at different running speeds, but the relationship between them is not completely clear. Understanding the relationship may result in training guidelines to reduce the injury risk. In this study, thirty-five participants with three different levels of running experience were recruited. Participants ran on three different surfaces (concrete, synthetic running track, and woodchip trail) at two different running speeds: a self-selected comfortable speed and a fixed speed of 3.06 m/s. Vertical acceleration of the lower leg was measured with an accelerometer. The vertical acceleration was significantly lower during running on the woodchip trail in comparison with the synthetic running track and the concrete, and significantly lower during running at lower speed in comparison with during running at higher speed on all surfaces. No significant differences in vertical acceleration were found between the three groups of runners at fixed speed. Higher self-selected speed due to higher performance level also did not result in higher vertical acceleration. These results may show that running on a woodchip trail and slowing down could reduce the injury risk at the tibia.

High-Speed Sealift Technology Development Plan

National Research Council Canada - National Science Library

2002-01-01

.... The purpose of the project was to define the technology investments required to enable development of the high-speed commercial and military ships needed to provide realistic future mission capabilities...

Surface electronic transport measurements: A micro multi-point probe approach

DEFF Research Database (Denmark)

Barreto, Lucas

2014-01-01

This work is mostly focused on the study of electronic transport properties of two-dimensional materials, in particular graphene and topological insulators. To study these, we have improved a unique micro multi-point probe instrument used to perform transport measurements. Not only the experimental...... quantities are extracted, such as conductivity, carrier density and carrier mobility. • A method to insulate electrically epitaxial graphene grown on metals, based on a stepwise intercalation methodology, is developed and transport measurements are performed in order to test the insulation. • We show...... a direct measurement of the surface electronic transport on a bulk topological insulator. The surface state conductivity and mobility are obtained. Apart from transport properties, we also investigate the atomic structure of the Bi2Se3(111) surface via surface x-ray diraction and low-energy electron...

Nitrogen concentration profiles in oxy-nitrited high-speed steel

International Nuclear Information System (INIS)

Barcz, A.; Turos, A.; Wielunski, L.

1976-01-01

Nuclear microanalysis has been applied for the determination of in-depth concentration profiles of nitrogen in oxy-nitrided high-speed steel. The concentration profiles were deduced from measurements of the nitrogen content, determined by means of the 14 N(d,α) 12 C reaction for the set of initially identical samples after the removal of surface layers of sequentially increasing thicknesses. The 1.2 MeV deuterons were obtained from the Institute of Nuclear Research Van de Graaf accelerator LECH. The α-particles produced in the 14 N(d,α) 12 C reaction were detected by means of silicon surface barrier detector mounted at 150 deg C. Strong blocking of the nitrogen diffusion due to the presence of oxygen has been observed. The accuracy of nitrogen detection is of the order of 5% for nitrogen-rich regions and 10% for the matrix. However, the local non-uniformity of the steel may cause a spread of about 20% of the measured values. (T.G.)

Diagnostics of high-speed streams and coronal holes using geomagnetic pulsations

International Nuclear Information System (INIS)

Bol'shakova, O.V.; Troitskaya, V.A.

1980-01-01

In order to study the relations of high-speed solar wind streams and coronal holes analyzed are the parameters of geomagnetic pulsations of the Rs3 type and of high-speed streams at the decrease branch and in the minimum of solar activity. On the basis of the analysis of exciting pulsation regime determined are the differences in characteristics of high-speed stream properties. Presented are the graphical distributions of a number of occurrances of high-speed streams, coronal holes and pure regimes of Rs3R pulsations in several sections of 1973 in the Sun rotations of N1903-1919 and of the change of solar wind velocity while passing through the high-speed streams. It is found that Rs3R occurrance can serve an indicator of the high-speed flux connection with the large equatorial coronal hole. On the basis of the analysis of exciting pulsation properties determined are the differences in the stream characteristics. However the preliminary estimates permit to adopt neither the first nor the second of the existing hypotheses on the sourse of formation of high-speed streams

Passenger Sharing of the High-Speed Railway from Sensitivity Analysis Caused by Price and Run-time Based on the Multi-Agent System

Directory of Open Access Journals (Sweden)

Ma Ning

2013-09-01

Full Text Available Purpose: Nowadays, governments around the world are active in constructing the high-speed railway. Therefore, it is significant to make research on this increasingly prevalent transport.Design/methodology/approach: In this paper, we simulate the process of the passenger’s travel mode choice by adjusting the ticket fare and the run-time based on the multi-agent system (MAS.Findings: From the research we get the conclusion that increasing the run-time appropriately and reducing the ticket fare in some extent are effective ways to enhance the passenger sharing of the high-speed railway.Originality/value: We hope it can provide policy recommendations for the railway sectors in developing the long-term plan on high-speed railway in the future.

Optimal design of high-speed loading spindle based on ABAQUS

Science.gov (United States)

Yang, Xudong; Dong, Yu; Ge, Qingkuan; Yang, Hai

2017-12-01

The three-dimensional model of high-speed loading spindle is established by using ABAQUS’s modeling module. A finite element analysis model of high-speed loading spindle was established by using spring element to simulate bearing boundary condition. The static and dynamic performance of the spindle structure with different specifications of the rectangular spline and the different diameter neck of axle are studied in depth, and the influence of different spindle span on the static and dynamic performance of the high-speed loading spindle is studied. Finally, the optimal structure of the high-speed loading spindle is obtained. The results provide a theoretical basis for improving the overall performance of the test-bed

Instantaneous phase-shifting Fizeau interferometry with high-speed pixelated phase-mask camera

Science.gov (United States)

Yatagai, Toyohiko; Jackin, Boaz Jessie; Ono, Akira; Kiyohara, Kosuke; Noguchi, Masato; Yoshii, Minoru; Kiyohara, Motosuke; Niwa, Hayato; Ikuo, Kazuyuki; Onuma, Takashi

2015-08-01

A Fizeou interferometer with instantaneous phase-shifting ability using a Wollaston prism is designed. to measure dynamic phase change of objects, a high-speed video camera of 10-5s of shutter speed is used with a pixelated phase-mask of 1024 × 1024 elements. The light source used is a laser of wavelength 532 nm which is split into orthogonal polarization states by passing through a Wollaston prism. By adjusting the tilt of the reference surface it is possible to make the reference and object beam with orthogonal polarizations states to coincide and interfere. Then the pixelated phase-mask camera calculate the phase changes and hence the optical path length difference. Vibration of speakers and turbulence of air flow were successfully measured in 7,000 frames/sec.

High-speed railway signal trackside equipment patrol inspection system

Science.gov (United States)

Wu, Nan

2018-03-01

High-speed railway signal trackside equipment patrol inspection system comprehensively applies TDI (time delay integration), high-speed and highly responsive CMOS architecture, low illumination photosensitive technique, image data compression technique, machine vision technique and so on, installed on high-speed railway inspection train, and achieves the collection, management and analysis of the images of signal trackside equipment appearance while the train is running. The system will automatically filter out the signal trackside equipment images from a large number of the background image, and identify of the equipment changes by comparing the original image data. Combining with ledger data and train location information, the system accurately locate the trackside equipment, conscientiously guiding maintenance.

Aircraft Emission Inventories Projected in Year 2015 for a High Speed Civil Transport (HSCT) Universal Airline Network. Final report

Energy Technology Data Exchange (ETDEWEB)

Baughcum, S.L.; Henderson, S.C.

1995-07-01

This report describes the development of a three-dimensional database of aircraft fuel burn and emissions (fuel burned, NOx, CO, and hydrocarbons) from projected fleets of high speed civil transports (HSCT`s) on a universal airline network. Inventories for 500 and 1000 HSCT fleets, as well as the concurrent subsonic fleets, were calculated. The objective of this work was to evaluate the changes in geographical distribution of the HSCT emissions as the fleet size grew from 500 to 1000 HSCT`s. For this work, a new expanded HSCT network was used and flights projected using a market penetration analysis rather than assuming equal penetration as was done in the earlier studies. Emission inventories on this network were calculated for both Mach 2.0 and Mach 2.4 HSCT fleets with NOx cruise emission indices of approximately 5 and 15 grams NOx/kg fuel. These emissions inventories are available for use by atmospheric scientists conducting the Atmospheric Effects of Stratospheric Aircraft (AESA) modeling studies. Fuel burned and emissions of nitrogen oxides (NOx as NO2), carbon monoxide, and hydrocarbons have been calculated on a 1 degree latitude x 1 degree longitude x 1 kilometer attitude grid and delivered to NASA as electronic files.

Quantitative Study for the Surface Dehydration of Vocal Folds Based on High-Speed Imaging.

Science.gov (United States)

Li, Lin; Zhang, Yu; Maytag, Allison L; Jiang, Jack J

2015-07-01

From the perspective of the glottal area and mucosal wave, quantitatively estimate the differences of vocal fold on laryngeal activity during phonation at three different dehydration levels. Controlled three sets of tests. A dehydration experiment for 10 excised canine larynges was conducted at 16 cm H2O. According to the dehydration cycle time (H), dehydration levels were divided into three degrees (0% H, 50% H, 75% H). The glottal area and mucosal wave under three dehydration levels were extracted from high-speed images and digital videokymography (DKG) image sequences. Direct and non-direct amplitude components were derived from glottal areas. The amplitude and frequency of mucosal wave were calculated from DKG image sequences. These parameters in condition of three dehydration levels were compared for statistical analysis. The results showed a significant difference in direct (P = 0.001; P = 0.005) and non-direct (P = 0.005; P = 0.016) components of glottal areas between every two different dehydration levels. Considering the right-upper, right-lower, left-upper, and left-lower of vocal fold, the amplitudes of mucosal waves consistently decreased with increasing of dehydration levels. But, there was no significant difference in frequency. Surface dehydration could give rise to complex variation of vocal fold on tissues and vibratory mechanism, which should need analyzing from multiple perspectives. The results suggested that the combination of glottal area and mucosal wave could be better to research the change of vocal fold at different dehydrations. It would become a better crucial research tool for the clinical treatment of dehydration-induced laryngeal pathologies. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Pulse-burst PIV in a high-speed wind tunnel

International Nuclear Information System (INIS)

Beresh, Steven; Kearney, Sean; Wagner, Justin; Guildenbecher, Daniel; Henfling, John; Spillers, Russell; Pruett, Brian; Jiang, Naibo; Slipchenko, Mikhail; Mance, Jason; Roy, Sukesh

2015-01-01

Time-resolved particle image velocimetry (TR-PIV) has been achieved in a high-speed wind tunnel, providing velocity field movies of compressible turbulence events. The requirements of high-speed flows demand greater energy at faster pulse rates than possible with the TR-PIV systems developed for low-speed flows. This has been realized using a pulse-burst laser to obtain movies at up to 50 kHz, with higher speeds possible at the cost of spatial resolution. The constraints imposed by use of a pulse-burst laser are limited burst duration of 10.2 ms and a low duty cycle for data acquisition. Pulse-burst PIV has been demonstrated in a supersonic jet exhausting into a transonic crossflow and in transonic flow over a rectangular cavity. The velocity field sequences reveal the passage of turbulent structures and can be used to find velocity power spectra at every point in the field, providing spatial distributions of acoustic modes. The present work represents the first use of TR-PIV in a high-speed ground-test facility. (paper)

Thermoelectric Transport by Surface States in Bi2Se3-Based Topological Insulator Thin Films

International Nuclear Information System (INIS)

Li Long-Long; Xu Wen

2015-01-01

We develop a tractable theoretical model to investigate the thermoelectric (TE) transport properties of surface states in topological insulator thin films (TITFs) of Bi 2 Se 3 at room temperature. The hybridization between top and bottom surface states in the TITF plays a significant role. With the increasing hybridization-induced surface gap, the electrical conductivity and electron thermal conductivity decrease while the Seebeck coefficient increases. This is due to the metal-semiconductor transition induced by the surface-state hybridization. Based on these TE transport coefficients, the TE figure-of-merit ZT is evaluated. It is shown that ZT can be greatly improved by the surface-state hybridization. Our theoretical results are pertinent to the exploration of the TE transport properties of surface states in TITFs and to the potential application of Bi 2 Se 3 -based TITFs as high-performance TE materials and devices. (paper)

High Resolution Mapping of Wind Speed Using Active Distributed Temperature Sensing

Science.gov (United States)

Sayde, C.; Thomas, C. K.; Wagner, J.; Selker, J. S.

2013-12-01

We present a novel approach to continuously measure wind speed simultaneously at thousands of locations using actively heated fiber optics with a distributed temperature sensing system (DTS). Analogous to a hot-wire anemometer, this approach is based on the principal of velocity-dependent heat transfer from a heated surface: The temperature difference between the heated surface and ambient air is a function of the convective cooling of the air flowing past the surface. By knowing the thermal properties of the heated surface, the heating input, and ambient temperature, wind speed can be calculated. In our case, the heated surface consists of a thin stainless steel tube that can exceed several km in length. A fiber optic is enclosed within the stainless steel tube to report the heated tube temperature, which in this case was sampled every 0.125 m. Ambient temperature were measured by an independent fiber optic cable located proximally to the stainless steel tube. We will present the theoretical bases of measuring wind speed using heated fiber optic as well as validation of this method in the field. In the field testing, more than 5000 simultaneous wind speed measurements were obtained every 5.5 second at 3 elevations (2m, 1m, and 0.5 m) every 0.125 m along a 230 m transects located across a shallow gulley in Nunn, CO. This method, which provides both air temperature and wind speed spanning four orders of magnitude in spatial scale (0.1 - 1,000m) opens up many important opportunities for testing basic theories in micro-meteorology regarding spatial scales of turbulent length scales as a function of distance from the earth, development of internal boundary layers, applicability of Taylors hypothesis, etc. The equipment employed, including the heating system, which is available to all US scientists, was provided by CTEMPs.org thanks to the generous grant support from the National Science Foundation under Grant Number 1129003. Any opinions, findings, and conclusions or

Investigation on the corrosion behavior of physical vapor deposition coated high speed steel

Directory of Open Access Journals (Sweden)

R Ravi Raja Malarvannan

2015-08-01

Full Text Available This work emphasizes on the influence of the TiN and AlCrN coatings fabricated on high speed steel form tool using physical vapor deposition technique. The surface microstructure of the coatings was studied using scanning electron microscope. Hardness and corrosion studies were also performed using Vickers hardness test and salt spray testing, respectively. The salt spray test results suggested that the bilayer coated (TiN- bottom layer and AlCrN- top layer substrate has undergone less amount of corrosion, and this is attributed to the dense microstructure. In addition to the above, the influence of the above coatings on the machining performance of the high speed steel was also evaluated and compared with that of the uncoated material and the results suggested that the bilayered coating has undergone very low weight loss when compared with that of the uncoated substrate depicting enhanced wear resistance.

Noise in the passenger cars of high-speed trains.

Science.gov (United States)

Hong, Joo Young; Cha, Yongwon; Jeon, Jin Yong

2015-12-01

The aim of this study is to investigate the effects of both room acoustic conditions and spectral characteristics of noises on acoustic discomfort in a high-speed train's passenger car. Measurement of interior noises in a high-speed train was performed when the train was operating at speeds of 100 km/h and 300 km/h. Acoustic discomfort caused by interior noises was evaluated by paired comparison methods based on the variation of reverberation time (RT) in a passenger car and the spectral differences in interior noises. The effect of RT on acoustic discomfort was not significant, whereas acoustic discomfort significantly varied depending on spectral differences in noise. Acoustic discomfort increased with increment of the sound pressure level (SPL) ratio at high frequencies, and variation in high-frequency noise components were described using sharpness. Just noticeable differences of SPL with low- and high-frequency components were determined to be 3.7 and 2.9 dB, respectively. This indicates that subjects were more sensitive to differences in SPLs at the high-frequency range than differences at the low-frequency range. These results support that, for interior noises, reduction in SPLs at high frequencies would significantly contribute to improved acoustic quality in passenger cars of high-speed trains.

High-speed optical signal processing using time lenses

DEFF Research Database (Denmark)

Galili, Michael; Hu, Hao; Guan, Pengyu

2015-01-01

This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle.......This paper will discuss time lenses and their broad range of applications. A number of recent demonstrations of complex high-speed optical signal processing using time lenses will be outlined with focus on the operating principle....

Speeds in school zones.

Science.gov (United States)

2009-02-01

School speed zones are frequently requested traffic controls for school areas, based on the common belief : that if the transportation agency would only install a reduced speed limit, then drivers would no longer : speed through the area. This resear...

Methane Bubbles Transport Particles From Contaminated Sediment to a Lake Surface

Science.gov (United States)

Delwiche, K.; Hemond, H.

2017-12-01

Methane bubbling from aquatic sediments has long been known to transport carbon to the atmosphere, but new evidence presented here suggests that methane bubbles also transport particulate matter to a lake surface. This transport pathway is of particular importance in lakes with contaminated sediments, as bubble transport could increase human exposure to toxic metals. The Upper Mystic Lake in Arlington, MA has a documented history of methane bubbling and sediment contamination by arsenic and other heavy metals, and we have conducted laboratory and field studies demonstrating that methane bubbles are capable of transporting sediment particles over depths as great as 15 m in Upper Mystic Lake. Methane bubble traps were used in-situ to capture particles adhered to bubble interfaces, and to relate particle mass transport to bubble flux. Laboratory studies were conducted in a custom-made 15 m tall water column to quantify the relationship between water column height and the mass of particulate transport. We then couple this particle transport data with historical estimates of ebullition from Upper Mystic Lake to quantify the significance of bubble-mediated particle transport to heavy metal cycling within the lake. Results suggest that methane bubbles can represent a significant pathway for contaminated sediment to reach surface waters even in relatively deep water bodies. Given the frequent co-occurrence of contaminated sediments and high bubble flux rates, and the potential for human exposure to heavy metals, it will be critical to study the significance of this transport pathway for a range of sediment and contaminant types.

High-speed parallel counter

International Nuclear Information System (INIS)

Gus'kov, B.N.; Kalinnikov, V.A.; Krastev, V.R.; Maksimov, A.N.; Nikityuk, N.M.

1985-01-01

This paper describes a high-speed parallel counter that contains 31 inputs and 15 outputs and is implemented by integrated circuits of series 500. The counter is designed for fast sampling of events according to the number of particles that pass simultaneously through the hodoscopic plane of the detector. The minimum delay of the output signals relative to the input is 43 nsec. The duration of the output signals can be varied from 75 to 120 nsec

Influence of “J”-Curve Spring Stiffness on Running Speeds of Segmented Legs during High-Speed Locomotion

Directory of Open Access Journals (Sweden)

Runxiao Wang

2016-01-01

Full Text Available Both the linear leg spring model and the two-segment leg model with constant spring stiffness have been broadly used as template models to investigate bouncing gaits for legged robots with compliant legs. In addition to these two models, the other stiffness leg spring models developed using inspiration from biological characteristic have the potential to improve high-speed running capacity of spring-legged robots. In this paper, we investigate the effects of “J”-curve spring stiffness inspired by biological materials on running speeds of segmented legs during high-speed locomotion. Mathematical formulation of the relationship between the virtual leg force and the virtual leg compression is established. When the SLIP model and the two-segment leg model with constant spring stiffness and with “J”-curve spring stiffness have the same dimensionless reference stiffness, the two-segment leg model with “J”-curve spring stiffness reveals that (1 both the largest tolerated range of running speeds and the tolerated maximum running speed are found and (2 at fast running speed from 25 to 40/92 m s−1 both the tolerated range of landing angle and the stability region are the largest. It is suggested that the two-segment leg model with “J”-curve spring stiffness is more advantageous for high-speed running compared with the SLIP model and with constant spring stiffness.

Integrated Seismic Survey for Detecting Landslide Effects on High Speed Rail Line at Istanbul–Turkey

Directory of Open Access Journals (Sweden)

Grit Mert

2016-02-01

Full Text Available 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.

High speed rotary drum

Energy Technology Data Exchange (ETDEWEB)

Sagara, H

1970-03-25

A high speed rotary drum is disclosed in which the rotor vessel is a double-wall structure comprising an inner wave-shaped pipe inserted coaxially within an outer straight pipe, the object being to provide a strengthened composite light-weight structure. Since force induced axial deformation of the straight pipe and radial deformation of the corrugated pipe are small, the composite effectively resists external forces and, if the waves of the inner pipe are given a sufficient amplitude, the thickness of both pipes may be reduced to lower the overall weight. Thus high angular velocities can be obtained to separate U/sup 235/ from gaseous UF/sub 6/.

Coronal holes and high-speed wind streams

International Nuclear Information System (INIS)

Zirker, J.B.

1977-01-01

Coronal holes low have been identified as Bartel's M regions, i.e., sources of high-speed wind streams that produce recurrent geomagnetic variations. Throughout the Skylab period the polar caps of the Sun were coronal holes, and at lower latitudes the most persistent and recurrent holes were equatorial extensions of the polar caps. The holes rotated 'rigidly' at the equatorial synodic rate. They formed in regions of unipolar photospheric magnetic field, and their internal magnetic fields diverged rapidly with increasing distance from the sun. The geometry of the magnetic field in the inner corona seems to control both the physical properties of the holes and the global distribution of high-speed wind streams in the heliosphere. The latitude variation of the divergence of the coronal magnetic field lines produces corresponding variations in wind speed.During the years of declining solar activity the global field of the corona approximates a perturbed dipole. The divergence of field lines in each hemisphere produces a high-speed wind near the poles and low-speed wind in a narrow belt that coincides with the magnetic neutral sheet. The analysis of electron density measurements within a polar hole indicates that solar wind is accelerated principally in the region between 2 and 5 R/sub s/ and that mechanical wave pressure (possibly Alfven wave) may be responsible for the accleration of the wind. Phenomenological models for the birth and decay of coronal holes have been proposed. Attempts to explain the birth and rigid rotation of holes through dynamo action have been only partially successful. The 11-year variation of cosmic ray intensities at the earth may result from cyclic variation of open field regions associated with coronal holes

The influence of wind speed on airflow and fine particle transport within different building layouts of an industrial city.

Science.gov (United States)

Mei, Dan; Wen, Meng; Xu, Xuemei; Zhu, Yuzheng; Xing, Futang

2018-04-20

In atmospheric environment, the layout difference of urban buildings has a powerful influence on accelerating or inhibiting the dispersion of particle matters (PM). In industrial cities, buildings of variable heights can obstruct the diffusion of PM from industrial stacks. In this study, PM dispersed within building groups was simulated by Reynolds-averaged Navier-Stokes equations coupled Lagrangian approach. Four typical street building arrangements were used: (a) a low-rise building block with Height/base H/b = 1 (b = 20 m); (b) step-up building layout (H/b = 1, 2, 3, 4); (c) step-down building layout (H/b = 4, 3, 2, 1); (d) high-rise building block (H/b = 5). Profiles of stream functions and turbulence intensity were used to examine the effect of various building layouts on atmospheric airflow. Here, concepts of particle suspension fraction and concentration distribution were used to evaluate the effect of wind speed on fine particle transport. These parameters showed that step-up building layouts accelerated top airflow and diffused more particles into street canyons, likely having adverse effects on resident health. In renewal old industry areas, the step-down building arrangement which can hinder PM dispersion from high-level stacks should be constructed preferentially. High turbulent intensity results in formation of a strong vortex that hinders particles into the street canyons. It is found that an increase in wind speed enhanced particle transport and reduced local particle concentrations, however, it did not affect the relative location of high particle concentration zones, which are related to building height and layout. This study has demonstrated the height variation and layout of urban architecture affect the local concentration distribution of particulate matter (PM) in the atmosphere and for the first time that wind velocity has particular effects on PM transport in various building groups. The findings may have general implications in optimization

TECHNICAL APPROACH TO THE EFFICIENCY DETERMINATION OF HIGH-SPEED TRAINS

Directory of Open Access Journals (Sweden)

A. V. Momot

2013-11-01

Full Text Available Purpose. The aim of this article is to develop an approach and formulate arrangements concerning the definition of the economic appropriateness of high-speed movement implementation in Ukraine. Methodology. The economic feasibility for appropriateness of high-speed movement organization in Ukraine is an investment project, which involves step-by-step money investment into the construction. It will let get an annual profits from the passenger carriage. To solve such problems we use net present value, which UZ or newly created companies can get during the project realization and after its completion. Findings. Obtained studies can state the fact that the technical approach for full effectiveness definition of a construction and high-speed passenger trains service taking into account the cost of infrastructure, rolling stock, the impact of environmental factors, etc. was determined. Originality. We propose a scientific approach to determine the economic effectiveness of the construction and high-speed main lines service. It includes improved principles of defining the passenger traffic, the cost of high-speed rails construction, the number of rolling stock; optimizes income and expenditure calculations in the context of competitive advantages and the external factors impact on the company. A technical approach for the calculation of future traffic volumes along the high-speed line was improved. It differs essentially from the European one proposed by the French firm «SYSTRA», as it allows taking into account additional transit traffic through Ukraine. It helps to distribute the passengers on separate sections proportionally to the number of cities population, which are combined by high-speed main line, subject to the average population mobility, travel time and the coefficient that takes into account the frequency of additional passenger trips on a given section, depending on the purpose (business trip, transfer to a plane, recreation, etc

Designing Sustainable Public Transportation: Integrated Optimization of Bus Speed and Holding Time in a Connected Vehicle Environment

Directory of Open Access Journals (Sweden)

Wei Wu

2016-11-01

Full Text Available Developing public transportation and giving priority to buses is a feasible solution for improving the level of public transportation service, which facilitates congestion alleviation and prevention, and contributes to urban development and city sustainability. This paper presents a novel bus operation control strategy including both holding control and speed control to improve the level of service of transit systems within a connected vehicle environment. Most previous work focuses on optimization of signal timing to decrease the bus signal delay by assuming that holding control is not applied; the speed of buses is given as a constant input and the acceleration and deceleration processes of buses can be neglected. This paper explores the benefits of a bus operation control strategy to minimize the total cost, which includes bus signal delay, bus holding delay, bus travel delay, acceleration cost due to frequent stops and intense driving. A set of formulations are developed to explicitly capture the interaction between bus holding control and speed control. Experimental analysisand simulation tests have shown that the proposed integrated operational model outperforms the traditional control, speed control only, or holding control only strategies in terms of reducing the total cost of buses. The sensitivity analysis has further demonstrated the potential effectiveness of the proposed approach to be applied in a real-time bus operation control system under different levels of traffic demand, bus stop locations, and speed limits.