Science.gov

Sample records for mobile helium-jet transport

  1. Mobile transporter path planning

    NASA Technical Reports Server (NTRS)

    Baffes, Paul; Wang, Lui

    1990-01-01

    The use of a genetic algorithm (GA) for solving the mobile transporter path planning problem is investigated. The mobile transporter is a traveling robotic vehicle proposed for the space station which must be able to reach any point of the structure autonomously. Elements of the genetic algorithm are explored in both a theoretical and experimental sense. Specifically, double crossover, greedy crossover, and tournament selection techniques are examined. Additionally, the use of local optimization techniques working in concert with the GA are also explored. Recent developments in genetic algorithm theory are shown to be particularly effective in a path planning problem domain, though problem areas can be cited which require more research.

  2. Space station mobile transporter

    NASA Technical Reports Server (NTRS)

    Renshall, James; Marks, Geoff W.; Young, Grant L.

    1988-01-01

    The first quarter of the next century will see an operational space station that will provide a permanently manned base for satellite servicing, multiple strategic scientific and commercial payload deployment, and Orbital Maneuvering Vehicle/Orbital Transfer Vehicle (OMV/OTV) retrieval replenishment and deployment. The space station, as conceived, is constructed in orbit and will be maintained in orbit. The construction, servicing, maintenance and deployment tasks, when coupled with the size of the station, dictate that some form of transportation and manipulation device be conceived. The Transporter described will work in conjunction with the Orbiter and an Assembly Work Platform (AWP) to construct the Work Station. The Transporter will also work in conjunction with the Mobile Remote Servicer to service and install payloads, retrieve, service and deploy satellites, and service and maintain the station itself. The Transporter involved in station construction when mounted on the AWP and later supporting a maintenance or inspection task with the Mobile Remote Servicer and the Flight Telerobotic Servicer is shown.

  3. High-Speed Rainbow Schlieren Visualization of an Oscillating Helium Jet Undergoing Gravitational Change

    NASA Technical Reports Server (NTRS)

    Leptuch, Peter A.; Agrawal, Ajay K.

    2005-01-01

    Rainbow schlieren deflectometry combined with high-speed digital imaging was used to study buoyancy effects on flow structure of a helium jet discharged vertically into air. The experimental data were taken using the 2.2-sec drop tower facility at the NASA John H. Glenn Research Center in Cleveland, Ohio. The test conditions pertained to jet Reynolds number of 490 and jet Richardson number of 0.11, for which buoyancy is often considered unimportant. Experimental results show global oscillations at a frequency of 27 Hz in Earth gravity. In microgravity, the jet oscillations vanished and the jet width increased. Results provide a direct physical evidence of the importance of buoyancy on the flow structure of low-density gas jets at a Richardson number considered too small to account for gravity.

  4. High-Speed Rainbow Schlieren Deflectometry Analysis of Helium Jets Flowing into Air for Microgravity Applications

    NASA Technical Reports Server (NTRS)

    Leptuch, Peter A.

    2002-01-01

    The flow phenomena of buoyant jets have been analyzed by many researchers in recent years. Few, however have studied jets in microgravity conditions, and the exact nature of the flow under these conditions has until recently been unknown. This study seeks to extend the work done by researchers at the university of Oklahoma in examining and documenting the behavior of helium jets in micro-gravity conditions. Quantitative rainbow schlieren deflectometry data have been obtained for helium jets discharging vertically into quiescent ambient air from tubes of several diameters at various flow rates using a high-speed digital camera. These data have obtained before, during and after the onset of microgravity conditions. High-speed rainbow schlieren deflectometry has been developed for this study with the installation and use of a high-speed digital camera and modifications to the optical setup. Higher temporal resolution of the transitional phase between terrestrial and micro-gravity conditions has been obtained which has reduced the averaging effect of longer exposure times used in all previous schlieren studies. Results include color schlieren images, color time-space images (temporal evolution images), frequency analyses, contour plots of hue and contour plots of helium mole fraction. The results, which focus primarily on the periods before and during the onset of microgravity conditions, show that the pulsation of the jets normally found in terrestrial gravity ("earth"-gravity) conditions cease, and the gradients in helium diminish to produce a widening of the jet in micro-gravity conditions. In addition, the results show that the disturbance propagate upstream from a downstream source.

  5. Full-Field Measurements of Self-Excited Oscillations in Momentum-Dominated Helium Jets

    NASA Technical Reports Server (NTRS)

    Yildirim, B. S.; Agrawal, A. K.

    2005-01-01

    Flow structure of momentum-dominated helium jets discharged vertically into ambient air was investigated using a high-speed rainbow schlieren deflectometry (RSD) apparatus operated at up to 2000 Hz. The operating parameters, i.e., Reynolds number and Richardson number were varied independently to examine the self-excited, flow oscillatory behavior over a range of experimental conditions. Measurements revealed highly periodic oscillations in the laminar region at a unique frequency as well as high regularity in the flow transition and initial turbulent regions. The buoyancy was shown to affect the oscillation frequency and the distance from the jet exit to the flow transition plane. Instantaneous helium concentration contours across the field of view revealed changes in the jet flow structure and the evolution of the vortical structures during an oscillation cycle. A cross-correlation technique was applied to track the vortices and to find their convection velocity. Time-traces of helium concentration at different axial locations provided detailed information about the oscillating flow.

  6. Concentration Measurements in Self-Excited, Momentum-Dominated Helium Jets

    NASA Technical Reports Server (NTRS)

    Yildirim, Bekir Sedat

    2004-01-01

    Flow structure of momentum-dominated pure helium jets discharged vertically into ambient air was investigated using high-speed rainbow schlieren deflectometry (RSD) technique. Effects of the operating parameters, i.e., Reynolds number (Re) and Richardson number (Ri), on the oscillatory behavior of the flow were examined over a range of experimental conditions. To seek the individual effect of these parameters, one of them was fixed and the other was varied with certain constraints. Measurements revealed highly periodic oscillations in the laminar region as well as high regularity in transition and turbulent regions. Maximum spectral power profiles at different axial locations indicated the oscillation amplitude increasing until the breakdown of the jet in the turbulent regime. The transition from the laminar to turbulent flow was also investigated. Fast Fourier transform analysis performed in the transition regime showed that the flow oscillates at a unique frequency, which was the same in the upstream laminar flow region. Measured deflection angle data were used in Abel inversion algorithm to construct the helium concentration fields. Instantaneous helium concentration contours revealed changes in the flow structure and evolution of vortical structures during an oscillation cycle. Temporal evolution plots of helium concentration at different axial location showed repeatable oscillations at all axial and radial locations up to the turbulent regime. A cross-correlation technique, applied to find the spatial displacements of the vortical structures, provided correlation coefficient peaks between consecutive schlieren images. Results show that the vortical structure convected and accelerated only in the axial direction.

  7. Effect of Gravity on the Near Field Flow Structure of Helium Jet in Air

    NASA Technical Reports Server (NTRS)

    Agrawal, Ajay K.; Parthasarathy, Ramkumar; Griffin, DeVon

    2002-01-01

    Experiments have shown that a low-density jet injected into a high-density surrounding medium undergoes periodic oscillations in the near field. Although the flow oscillations in these jets at Richardson numbers about unity are attributed to the buoyancy, the direct physical evidence has not been acquired in the experiments. If the instability were indeed caused by buoyancy, the near-field flow structure would undergo drastic changes upon removal of gravity in the microgravity environment. The present study was conducted to investigate this effect by simulating microgravity environment in the 2.2-second drop tower at the NASA Glenn Research Center. The non-intrusive, rainbow schlieren deflectometry technique was used for quantitative measurements of helium concentrations in buoyant and non-buoyant jets. Results in a steady jet show that the radial growth of the jet shear layer in Earth gravity is hindered by the buoyant acceleration. The jet in microgravity was 30 to 70 percent wider than that in Earth gravity. The microgravity jet showed typical growth of a constant density jet shear layer. In case of a self-excited helium jet in Earth gravity, the flow oscillations continued as the jet flow adjusted to microgravity conditions in the drop tower. The flow oscillations were however not present at the end of the drop when steady microgravity conditions were reached.

  8. Visualizing Mobility of Public Transportation System.

    PubMed

    Zeng, Wei; Fu, Chi-Wing; Arisona, Stefan Müller; Erath, Alexander; Qu, Huamin

    2014-12-01

    Public transportation systems (PTSs) play an important role in modern cities, providing shared/massive transportation services that are essential for the general public. However, due to their increasing complexity, designing effective methods to visualize and explore PTS is highly challenging. Most existing techniques employ network visualization methods and focus on showing the network topology across stops while ignoring various mobility-related factors such as riding time, transfer time, waiting time, and round-the-clock patterns. This work aims to visualize and explore passenger mobility in a PTS with a family of analytical tasks based on inputs from transportation researchers. After exploring different design alternatives, we come up with an integrated solution with three visualization modules: isochrone map view for geographical information, isotime flow map view for effective temporal information comparison and manipulation, and OD-pair journey view for detailed visual analysis of mobility factors along routes between specific origin-destination pairs. The isotime flow map linearizes a flow map into a parallel isoline representation, maximizing the visualization of mobility information along the horizontal time axis while presenting clear and smooth pathways from origin to destinations. Moreover, we devise several interactive visual query methods for users to easily explore the dynamics of PTS mobility over space and time. Lastly, we also construct a PTS mobility model from millions of real passenger trajectories, and evaluate our visualization techniques with assorted case studies with the transportation researchers.

  9. Full Field Scalar Measurements in a Pulsating Helium Jet using Rainbow Schlieren Deflectometry

    NASA Technical Reports Server (NTRS)

    Pasumarthi, Kasyap S.

    2000-01-01

    The flow structure of a pulsating helium jet was investigated using quantitative rainbow schlieren deflectometry. The operating parameters included the tube inside diameter, the jet Reynolds number and the jet Richardson number. The jet structure was characterized by the frequency spectrum, temporal evolution of the oscillations and mean and root-mean-square profiles of the species mole fraction, which in this case, was helium. Experiments were conducted using a variable nozzle facility. Angular deflection data were obtained using rainbow schlieren deflectometry across full field of color images taken at a temporal resolution of 60Hz. The flicker cycle was analyzed by instantaneous rainbow schlieren images, contour plots of deflection angle and helium mole fraction placed sequentially in time. Two observe the flow downstream, the tube was lowered with respect to the optical setup and images were taken at different axial planes. In this way, the laminar, transition and turbulent regions of the jet flow were observed. Abel inversion algorithm was utilized to reconstruct the refractive index field from the measurements of the beam deflection angle. The concentration field was then generated from the refractive index field. The phenomenon of vortex initiation and propagation in the flicker cycle was described by correlating the ray deflection angle and concentration contour plots. Experiments in the flickering jet reveal global oscillation in the flow field. The effect of jet exit Reynolds number and jet Richardson number on the flickering frequency was analyzed. The effect of jet Richardson number was more pronounced than that of the jet exit Reynolds number. The flow field was studies quantitatively in terms of temporal evolution and statistical description of helium mole fraction.

  10. Scalar Measurements and Analysis of Helium Jets in Earth Gravity and Microgravity using Rainbow Schlieren Deflectometry

    NASA Technical Reports Server (NTRS)

    Yep, Tze Wing

    2001-01-01

    Recent experiments have shown that low-density gas jets injected into a high-density gas undergo an instability mode leading to highly periodic oscillations in the flow field. The transition from laminar to turbulent flow in these jets is abrupt, without a gradual change in scales. Although this type of instability at high Richardson numbers has been attributed to buoyancy, direct physical evidence was not acquired through experiments. In this study, several experiments were conducted in Earth gravity and microgravity to acquire qualitative data on near field flow structure of helium jets injected into air. Microgravity conditions were simulated in the 2.2-second drop tower at NASA Glenn Research Center. The operating parameters of this study included the tube inside diameter, the jet Reynolds number, and the jet Richardson number. Tubes with inside diameters of 19.05 mm and 31.75 mm were used in the experiments conducted in the drop tower. The jet flow was analyzed using quantitative rainbow schlieren deflectometry, a non-intrusive line of sight measurement technique for the whole field. The flow structure was characterized by distributions of angular deflection and the resulting helium mole fraction obtained from color schlieren images taken at 60 Hz. Three sets of experimental data with respect to three schlieren fields of view were acquired for each tube. Results show that the jet in microgravity was up to 70 percent wider than that in Earth gravity. The global jet flow oscillations observed in Earth gravity were absent in microgravity, providing direct experimental evidence that the flow instability in the low-density jet was buoyancy-induced. This study provides quantitative details of temporal flow evolution as the experiments undergo change in gravity in the drop tower.

  11. A comprehensive statistical investigation of schlieren image velocimetry (SIV) using high-velocity helium jet

    NASA Astrophysics Data System (ADS)

    Biswas, Sayan; Qiao, Li

    2017-03-01

    A detailed statistical assessment of seedless velocity measurement using Schlieren Image Velocimetry (SIV) was explored using open source Robust Phase Correlation (RPC) algorithm. A well-known flow field, an axisymmetric turbulent helium jet, was analyzed near and intermediate region (0≤ x/d≤ 20) for two different Reynolds numbers, Re d = 11,000 and Re d = 22,000 using schlieren with horizontal knife-edge, schlieren with vertical knife-edge and shadowgraph technique, and the resulted velocity fields from SIV techniques were compared to traditional Particle Image Velocimetry (PIV) measurements. A novel, inexpensive, easy to setup two-camera SIV technique had been demonstrated to measure high-velocity turbulent jet, with jet exit velocities 304 m/s (Mach = 0.3) and 611 m/s (Mach = 0.6), respectively. Several image restoration and enhancement techniques were tested to improve signal to noise ratio (SNR) in schlieren and shadowgraph images. Processing and post-processing parameters for SIV techniques were examined in detail. A quantitative comparison between self-seeded SIV techniques and traditional PIV had been made using correlation statistics. While the resulted flow field from schlieren with horizontal knife-edge and shadowgraph showed excellent agreement with PIV measurements, schlieren with vertical knife-edge performed poorly. The performance of spatial cross-correlations at different jet locations using SIV techniques and PIV was evaluated. Turbulence quantities like turbulence intensity, mean velocity fields, Reynolds shear stress influenced spatial correlations and correlation plane SNR heavily. Several performance metrics such as primary peak ratio (PPR), peak to correlation energy (PCE), the probability distribution of signal and noise were used to compare capability and potential of different SIV techniques.

  12. Crawler transporter nears the Mobile Launch Platform

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The crawler transporter nears the Mobile Launch Platform and Space Shuttle Discovery to await possible orders for a rollback. KSC managers developed a precautionary plan to roll back Discovery to the Vehicle Assembly Building in the event that Hurricane Georges threatens Central Florida. The decision was made to minimize risk and provide protection to the Space Shuttle national asset

  13. Modeling Facilitated Contaminant Transport by Mobile Bacteria

    NASA Astrophysics Data System (ADS)

    Corapcioglu, M. Yavuz; Kim, Seunghyun

    1995-01-01

    Introduction of exogenous biocolloids such as genetically engineered bacteria in a bioremediation operation can enhance the transport of contaminants in groundwater by reducing the retardation effects. Because of their colloidal size and favorable surface conditions, bacteria are efficient contaminant carriers. In cases where contaminants have a low mobility in porous media because of their high partition with solid matrix, facilitated contaminant transport by mobile bacteria can create high contaminant fluxes. When metabolically active mobile bacteria are present in a subsurface environment, the system can be treated as consisting of three phases: water phase, bacterial phase, and stationary solid matrix phase. In this work a mathematical model based on mass balance equations is developed to describe the facilitated transport and fate of a contaminant and bacteria in a porous medium. Bacterial partition between the bulk solution and the stationary solid matrix and contaminant partition among three phases are represented by expressions in terms of measurable quantities. Solutions were obtained to provide estimates of contaminant and bacterial concentrations. A dimensional analysis of the transport model was utilized to estimate model parameters from the experimental data and to assess the effect of several parameters on model behavior. The model results matched favorably with experimental data of Jenkins and Lion (1993). The presence of mobile bacteria enhances the contaminant transport. However, bacterial consumption of the contaminant, which serves as a bacterial nutrient, can attenuate the contaminant mobility. The work presented in this paper is the first three-phase model to include the effects of substrate metabolism on the fate of groundwater contaminants.

  14. Transportation dynamics on networks of mobile agents.

    PubMed

    Yang, Han-Xin; Wang, Wen-Xu; Xie, Yan-Bo; Lai, Ying-Cheng; Wang, Bing-Hong

    2011-01-01

    Most existing works on transportation dynamics focus on networks of a fixed structure, but networks whose nodes are mobile have become widespread, such as cell-phone networks. We introduce a model to explore the basic physics of transportation on mobile networks. Of particular interest is the dependence of the throughput on the speed of agent movement and the communication range. Our computations reveal a hierarchical dependence for the former, while an algebraic power law is found between the throughput and the communication range with the exponent determined by the speed. We develop a physical theory based on the Fokker-Planck equation to explain these phenomena. Our findings provide insights into complex transportation dynamics arising commonly in natural and engineering systems.

  15. Transportation dynamics on networks of mobile agents

    NASA Astrophysics Data System (ADS)

    Yang, Han-Xin; Wang, Wen-Xu; Xie, Yan-Bo; Lai, Ying-Cheng; Wang, Bing-Hong

    2011-01-01

    Most existing works on transportation dynamics focus on networks of a fixed structure, but networks whose nodes are mobile have become widespread, such as cell-phone networks. We introduce a model to explore the basic physics of transportation on mobile networks. Of particular interest is the dependence of the throughput on the speed of agent movement and the communication range. Our computations reveal a hierarchical dependence for the former, while an algebraic power law is found between the throughput and the communication range with the exponent determined by the speed. We develop a physical theory based on the Fokker-Planck equation to explain these phenomena. Our findings provide insights into complex transportation dynamics arising commonly in natural and engineering systems.

  16. Advances in the helium-jet coupled on-line mass separator RAMA. [Recoil Atom Mass Analyzer

    SciTech Connect

    Moltz, D M; Aysto, J; Cable, M D; Parry, R F; Haustein, P E; Wouters, J M; Cerny, J

    1980-01-01

    General improvements to the on-line mass separator RAMA (Recoil Atom Mass Analyzer) have yielded a greater reliability and efficiency for some elements. A new utilitarian helium-jet chamber has been installed to facilitate quick target and degrader foil changes in addition to a new ion source holder. A higher efficiency hollow-cathode, cathode-extraction ion source, for lower melting point elements (< 1200/sup 0/C) has also been designed. Tests with the beta-delayed proton emitter /sup 37/Ca showed a factor of five increase in yield over the old hollow-cathode, anode-extraction source. A differentially-pumped-tape drive system compatible with both ..gamma..-..gamma.. and ..beta..-..gamma.. experiments has been incorporated into the general detection system. All major operating parameters will soon be monitored by a complete stand-alone microprocessor system which will eventually be upgraded to a closed-loop control system.

  17. Investigation on streamers propagating into a helium jet in air at atmospheric pressure: Electrical and optical emission analysis

    NASA Astrophysics Data System (ADS)

    Gazeli, K.; Svarnas, P.; Vafeas, P.; Papadopoulos, P. K.; Gkelios, A.; Clément, F.

    2013-09-01

    The plasma produced due to streamers guided by a dielectric tube and a helium jet in atmospheric air is herein studied electrically and optically. Helium streamers are produced inside the dielectric tube of a coaxial dielectric-barrier discharge and, upon exiting the tube, they propagate into the helium jet in air. The axisymmetric velocity field of the neutral helium gas while it penetrates the air is approximated with the PISO algorithm. At the present working conditions, turbulence helium flow is avoided. The system is driven by sinusoidal high voltage of variable amplitude (0-11 kV peak-to-peak) and frequency (5-20 kHz). It is clearly shown that a prerequisite for streamer development is a continuous flow of helium, independently of the sustainment or not of the dielectric-barrier discharge. A parametric study is carried out by scanning the range of the operating parameters of the system and the optimal operational window for the longest propagation path of the streamers in air is determined. For this optimum, the streamer current impulses and the spatiotemporal progress of the streamer UV-visible emission are recorded. The streamer mean propagation velocity is as well measured. The formation of copious reactive emissive species is then considered (in terms of intensity and rotational temperatures), and their evolution along the streamer propagation path is mapped. The main claims of the present work contribute to the better understanding of the physicochemical features of similar systems that are currently applied to various interdisciplinary engineering fields, including biomedicine and material processing.

  18. A mobile transporter concept for EVA assembly of future spacecraft

    NASA Technical Reports Server (NTRS)

    Watson, Judith J.; Bush, Harold G.; Heard, Walter L., Jr.; Lake, Mark S.; Jensen, J. Kermit

    1990-01-01

    This paper details the ground test program for the NASA Langley Research Center Mobile Transporter concept. The Mobile Transporter would assist EVA astronauts in the assembly of the Space Station Freedom. 1-g and simulated O-g (neutral buoyancy) tests were conducted to evaluate the use of the Mobile Transporter. A three-bay (44 struts) orthogonal tetrahedral truss configuration with a 15-foot-square cross section was repeatedly assembled by a single pair of pressure suited test subjects working from the Mobile Transporter astronaut positioning devices. The average unit assembly time was 28 seconds/strut. The results of these tests indicate that the use of a Mobile Transporter for EVA assembly of Space Station size structure is viable and practical. Additionally, the Mobile Transporter could be used to construct other spacecraft such as the submillimeter astronomical laboratory, space crane, and interplanetary (i.e., Mars and lunar) spacecraft.

  19. Fluctuating mobility generation and transport in glasses.

    PubMed

    Wisitsorasak, Apiwat; Wolynes, Peter G

    2013-08-01

    In the context of the random first order transition theory we use an extended mode coupling theory of the glass transition that includes activated events to account for spatiotemporal structures in rejuvenating glasses. We numerically solve fluctuating dynamical equations for mobility and fictive temperature fields which capture both mobility generation through activated events and facilitation effects. Upon rejuvenating, a source of high mobility at a glass surface initiates a growth front of mobility which propagates into the unstable low mobility region. The speed of the front quantitatively agrees with experiments on the rejuvenation of ultrastable glasses, which "melt" from their surface.

  20. High-sensitivity laser spectroscopy with atoms from a cooled helium jet

    SciTech Connect

    Lewis, D.A.; Evans, R.M.; Davids, C.N.; Finn, M.A.; Kaufman, S.L.; Greenlees, G.W.

    1983-01-01

    We have developed a cryogenic He-jet system which efficiently transports radioactive atoms produced on-line at the Argonne National Laboratory Tandem-Linac Accelertor away from the production region and forms them into a cool atomic beam. This atomic beam will be probed with high sensitivity laser spectroscopy using the photon burst method. The ultimate goal of this work is to determine the sizes, shapes, and magnetic moments of short-lived nuclei through their atomic hyperfine structure. Preliminary measurements with the He-jet system and the adaption of the photon burst method to this new geometry are described.

  1. Efficient Mobility Summit: Transportation and the Future of Dynamic Mobility Systems

    SciTech Connect

    2015-12-01

    On October 27, 2015, The U.S. Department of Energy's National Renewable Energy Laboratory (NREL) brought together local and national thought leaders to discuss the convergence of connectivity, vehicle automation, and transportation infrastructure investments at the Future Energy Efficient Mobility Workshop. The half-day workshop was held in conjunction with the Colorado Department of Transportation's (CDOT) Transportation Matters Summit and featured four panel sessions that showcased perspectives on efficient mobility from federal and state agencies, automakers and their suppliers, transportation data providers, and freight companies. This summary provides highlights from the meeting's exchanges of ideas and existing applications. Transportation's (CDOT) Transportation Matters Summit and featured four panel sessions that showcased perspectives on efficient mobility from federal and state agencies, automakers and their suppliers, transportation data providers, and freight companies. This summary provides highlights from the meeting's exchanges of ideas and existing applications.

  2. Location Management in a Transport Layer Mobility Architecture

    NASA Technical Reports Server (NTRS)

    Eddy, Wesley M.; Ishac, Joseph

    2005-01-01

    Mobility architectures that place complexity in end nodes rather than in the network interior have many advantageous properties and are becoming popular research topics. Such architectures typically push mobility support into higher layers of the protocol stack than network layer approaches like Mobile IP. The literature is ripe with proposals to provide mobility services in the transport, session, and application layers. In this paper, we focus on a mobility architecture that makes the most significant changes to the transport layer. A common problem amongst all mobility protocols at various layers is location management, which entails translating some form of static identifier into a mobile node's dynamic location. Location management is required for mobile nodes to be able to provide globally-reachable services on-demand to other hosts. In this paper, we describe the challenges of location management in a transport layer mobility architecture, and discuss the advantages and disadvantages of various solutions proposed in the literature. Our conclusion is that, in principle, secure dynamic DNS is most desirable, although it may have current operational limitations. We note that this topic has room for further exploration, and we present this paper largely as a starting point for comparing possible solutions.

  3. Numerical Analysis of Flow Evolution in a Helium Jet Injected into Ambient Air

    NASA Technical Reports Server (NTRS)

    Satti, Rajani P.; Agrawal, Ajay K.

    2005-01-01

    A computational model to study the stability characteristics of an evolving buoyant helium gas jet in ambient air environment is presented. Numerical formulation incorporates a segregated approach to solve for the transport equations of helium mass fraction coupled with the conservation equations of mixture mass and momentum using a staggered grid method. The operating parameters correspond to the Reynolds number varying from 30 to 300 to demarcate the flow dynamics in oscillating and non-oscillating regimes. Computed velocity and concentration fields were used to analyze the flow structure in the evolving jet. For Re=300 case, results showed that an instability mode that sets in during the evolution process in Earth gravity is absent in zero gravity, signifying the importance of buoyancy. Though buoyancy initiates the instability, below a certain jet exit velocity, diffusion dominates the entrainment process to make the jet non-oscillatory as observed for the Re=30 case. Initiation of the instability was found to be dependent on the interaction of buoyancy and momentum forces along the jet shear layer.

  4. Urban transportation: Perspectives on mobility and choice

    NASA Technical Reports Server (NTRS)

    Sincoff, M. Z. (Editor); Dajani, J. S. (Editor); Arnold, G. R.; Bird, J. W.; Brooks, C. M. (Editor); Cobb, W. E.; Cross, J. E.; Darby, L. F.; Erb, N. H.; Ficht, J. C.

    1974-01-01

    A study of urban transportation systems are presented characterized by intensive scrutiny of many ideas, philosophies, and academic perspectives. This report is intended to communicate some dimensions of the urban transportation problem to the general public.

  5. Dust mobilization and transport modeling for loss of vacuum accidents

    SciTech Connect

    P.W. Humrickhouse; J.P. Sharpe

    2007-10-01

    We develop a general continuum fluid dynamic model for dust transport in loss of vacuum accidents in fusion energy systems. The relationship between this general approach and established particle transport methods is clarified, in particular the relationship between the seemingly disparate treatments of aerosol dynamics and Lagrangian particle tracking. Constitutive equations for granular flow are found to be inadequate for prediction of mobilization, as these models essentially impose a condition of flow from the outset. Experiments confirm that at low shear, settled dust piles behave more like a continuum solid, and suitable solid models will be required to predict the onset of dust mobilization.

  6. PONS - Mobility Assistance on Footpaths for Public Transportation.

    PubMed

    Koutny, Reinhard; Miesenberger, Klaus

    2015-01-01

    This paper presents an ongoing project targeting mobility support for users of public transportation including people with limited mobility. Existing approaches in this field mostly offer non-continuous guidance during the whole journey including multiple rides with different vehicles and footpaths in between at transfer points. Especially people with limited mobility, like people with disabilities and elderly people, or travelers who are not familiar with the specific route or transfer point, like tourists, often struggle with public transportation. They crave for a seamless approach covering all links of the mobility chain - the sequence of sections of the whole route - and providing comprehensive assistance throughout the whole journey. Previous projects and widespread experiences of project partners revealed that especially footpath sections are lacking proper support. In particular, the consortium identified three problem areas in existing approaches when dealing with footpath sections: (1) A lack of information, (2) a lack of orientation and (3) a lack of provision of services. In order to bridge (lat. PONS) these gaps in the mobility chain, new paradigms and technology concepts are developed to tackle the shortcomings on footpaths and combined in a toolkit to help developers of applications with focus on pedestrian navigation and public transport to improve their solutions with sustainable and state-of-the-art approaches.

  7. A case study of mobilization and transport of Saharan dust

    NASA Technical Reports Server (NTRS)

    Westphal, Douglas L.; Toon, Owen B.; Carlson, Toby N.

    1988-01-01

    The mobilization and transport of the Saharan dust over the West Africa and the tropical Atlantic Ocean during the days of August 23-28, 1974, were investigated using the data set developed by GFDL, together with numerical models of the atmosphere and aerosol. It was found that the mobilization of dust during this period was related to the passage of a shallow easterly wave; mobilization was effected by dry convective mixing of low-level jets associated with the easterly wave. Model simulations show that the aerosol at any one point can be a complicated mixture of particles lifted at different times and different places; bimodal size distributions developed when dust was mobilized within a dust plume that was generated on a previous day.

  8. Making Transporter Models for Drug-Drug Interaction Prediction Mobile.

    PubMed

    Ekins, Sean; Clark, Alex M; Wright, Stephen H

    2015-10-01

    The past decade has seen increased numbers of studies publishing ligand-based computational models for drug transporters. Although they generally use small experimental data sets, these models can provide insights into structure-activity relationships for the transporter. In addition, such models have helped to identify new compounds as substrates or inhibitors of transporters of interest. We recently proposed that many transporters are promiscuous and may require profiling of new chemical entities against multiple substrates for a specific transporter. Furthermore, it should be noted that virtually all of the published ligand-based transporter models are only accessible to those involved in creating them and, consequently, are rarely shared effectively. One way to surmount this is to make models shareable or more accessible. The development of mobile apps that can access such models is highlighted here. These apps can be used to predict ligand interactions with transporters using Bayesian algorithms. We used recently published transporter data sets (MATE1, MATE2K, OCT2, OCTN2, ASBT, and NTCP) to build preliminary models in a commercial tool and in open software that can deliver the model in a mobile app. In addition, several transporter data sets extracted from the ChEMBL database were used to illustrate how such public data and models can be shared. Predicting drug-drug interactions for various transporters using computational models is potentially within reach of anyone with an iPhone or iPad. Such tools could help prioritize which substrates should be used for in vivo drug-drug interaction testing and enable open sharing of models.

  9. Mobile model and transportation planning: A brief overview

    SciTech Connect

    1996-04-01

    MOBILE is a computer model developed by the U.S. Environmental Protection Agency (EPA) for estimating emissions of air pollutants by motor vehicles. Using information on the types and ages of vehicles and on local driving conditions, MOBILE estimates emissions of various pollutants during each mile that different types of vehicles are driven. These emissions rates are combined with transportation planners` estimated of the number of miles vehicles are driven within the region to estimate area-wide total emissions of each pollutant by highway vehicles, usually during a day or year.

  10. 41 CFR 302-10.5 - May I transport a mobile home over water?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 4 2010-07-01 2010-07-01 false May I transport a mobile home over water? 302-10.5 Section 302-10.5 Public Contracts and Property Management Federal Travel... transport a mobile home over water? Yes, you may transport a mobile home over water when both the points...

  11. 41 CFR 302-10.5 - May I transport a mobile home over water?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 4 2013-07-01 2012-07-01 true May I transport a mobile home over water? 302-10.5 Section 302-10.5 Public Contracts and Property Management Federal Travel... transport a mobile home over water? Yes, you may transport a mobile home over water when both the points...

  12. 41 CFR 302-10.5 - May I transport a mobile home over water?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false May I transport a mobile home over water? 302-10.5 Section 302-10.5 Public Contracts and Property Management Federal Travel... transport a mobile home over water? Yes, you may transport a mobile home over water when both the points...

  13. Transportation during periods of mobilization: a historical review. Final report

    SciTech Connect

    Middendorf, D.P.; Johnson, L.R.

    1984-07-01

    The effects of the US transportation system of military preparations for war are compounded by the concurrent transportation requirements of economic mobilization to support a war effort. Several studies of military logistics have concluded that the transportation system may be the limiting factor in determining whether there is a successful operation. The responsiveness of the US transportation system during recent military conflicts is reviewed, beginning with the Spanish-American War and continuing through the Korean War. The nature and scope of each war is characterized, and the associated mobilization is described. Technological developments and regulatory changes in the transportation system since World War II are also reviewed in terms of their implications for the response capability of the nation. The dominant theme that emerges from this study is the overriding need for close coordination between modes and appropriate setting of priorities for shipments. The lack of an efficient system ultimately results in severe congestion at ports and terminals. The critical importance of the merchant marine fleet in overseas conflicts during the previous wars is also identified.

  14. Thermoelectric transport properties of high mobility organic semiconductors

    NASA Astrophysics Data System (ADS)

    Venkateshvaran, Deepak; Broch, Katharina; Warwick, Chris N.; Sirringhaus, Henning

    2016-09-01

    Transport in organic semiconductors has traditionally been investigated using measurements of the temperature and gate voltage dependent mobility of charge carriers within the channel of organic field-effect transistors (OFETs). In such measurements, the behavior of charge carrier mobility with temperature and gate voltage, studied together with carrier activation energies, provide a metric to quantify the extent of disorder within these van der Waals bonded materials. In addition to the mobility and activation energy, another potent but often-overlooked transport coefficient useful in understanding disorder is the Seebeck coefficient (also known as thermoelectric power). Fundamentally, the Seebeck coefficient represents the entropy per charge carrier in the solid state, and thus proves powerful in distinguishing materials in which charge carriers move freely from those where a high degree of disorder causes the induced carriers to remain trapped. This paper briefly covers the recent highlights in the field of organic thermoelectrics, showing how significant strides have been made both from an applied standpoint as well as from a viewpoint of fundamental thermoelectric transport physics. It shall be illustrated how thermoelectric transport parameters in organic semiconductors can be tuned over a significant range, and how this tunability facilitates an enhanced performance for heat-to-electricity conversion as well as quantifies energetic disorder and the nature of the density of states (DOS). The work of the authors shall be spotlighted in this context, illustrating how Seebeck coefficient measurements in the polymer indacenodithiophene-co-benzothiadiazole (IDTBT) known for its ultra-low degree of torsion within the polymer backbone, has a trend consistent with low disorder. 1 Finally, using examples of the small molecules C8-BTBT and C10-DNTT, it shall be discussed how the Seebeck coefficient can aid the estimation of the density and distribution of trap states

  15. Object Transportation by Two Mobile Robots with Hand Carts

    PubMed Central

    Hara, Tatsunori

    2014-01-01

    This paper proposes a methodology by which two small mobile robots can grasp, lift, and transport large objects using hand carts. The specific problems involve generating robot actions and determining the hand cart positions to achieve the stable loading of objects onto the carts. These problems are solved using nonlinear optimization, and we propose an algorithm for generating robot actions. The proposed method was verified through simulations and experiments using actual devices in a real environment. The proposed method could reduce the number of robots required to transport large objects with 50–60%. In addition, we demonstrated the efficacy of this task in real environments where errors occur in robot sensing and movement. PMID:27433499

  16. Conceptual design proposal: HUGO global range/mobility transport aircraft

    NASA Technical Reports Server (NTRS)

    Johnston, Tom; Perretta, Dave; Mcbane, Doug; Morin, Greg; Thomas, Greg; Woodward, Joe; Gulakowski, Steve

    1993-01-01

    With the collapse of the former Soviet Union and the emergence of the United Nations actively pursuing a peace keeping role in world affairs, the United States has been forced into a position as the world's leading peace enforcer. It is still a very dangerous world with seemingly never ending ideological, territorial, and economic disputes requiring the U.S. to maintain a credible deterrent posture in this uncertain environment. This has created an urgent need to rapidly transport large numbers of troops and equipment from the continental United States (CONUS) to any potential world trouble spot by means of a global range/mobility transport aircraft. The most recent examples being Operation Desert Shield/Storm and Operation Restore Hope. To meet this challenge head-on, a request for proposal (RFP) was developed and incorporated into the 1992/1993 AIAA/McDonnell Douglas Corporation Graduate Team Aircraft Design Competition. The RFP calls for the conceptual design and justification of a large aircraft capable of power projecting a significant military force without surface transportation reliance.

  17. Colloid Mobilization and Transport during Capillary Fringe Fluctuations

    NASA Astrophysics Data System (ADS)

    Aramrak, Surachet; Flury, Markus

    2016-04-01

    Capillary fringe fluctuations due to changing water tables lead to displacement of air-water interfaces in soils and sediments. These moving air-water interfaces can mobilize colloids. We visualized colloids interacting with moving air-water interfaces during capillary fringe fluctuations by confocal microscopy. We simulated capillary fringe fluctuations in a glass-bead filled column. Confocal images showed that the capillary fringe fluctuations affect colloid transport behavior. Hydrophilic negatively-charged colloids initially suspended in the aqueous phase were deposited at the solid-water interface after a drainage passage, but then were removed by subsequent capillary fringe fluctuations. The colloids that were initially attached to the wet or dry glass bead surface were detached by moving air-water interfaces in the capillary fringe. Hydrophilic negatively-charged colloids did not attach to static air-bubbles, but hydrophobic negatively-charged and hydrophilic positively-charged colloids did.

  18. On mobile element transport in heated Abee. [chondrite thermal metamorphism

    NASA Technical Reports Server (NTRS)

    Ikramuddin, M.; Lipschutz, M. E.; Gibson, E. K., Jr.

    1979-01-01

    Abee chondrite samples were heated at 700 C for one week at 0.00001 to 0.001 atm Ne or at 0.00001 atm H2. Samples heated in Ne showed greater loss of Bi and Se and greater retention of Zn than those heated in H2. An inverse relationship between Zn retention and ambient Ne pressure was found. Seven trace elements (Ag, Co, Cs, Ga, In, Te, and Tl) were retained or lost to the same extent regardless of the heating conditions. Variations in the apparent activation energy for C above and below 700 C suggest that diffusive loss from different hosts and/or different mobile transport processes over the temperature range may have been in effect.

  19. Colloid mobilization and transport during capillary fringe fluctuations.

    PubMed

    Aramrak, Surachet; Flury, Markus; Harsh, James B; Zollars, Richard L

    2014-07-01

    Capillary fringe fluctuations due to changing water tables lead to displacement of air-water interfaces in soils and sediments. These moving air-water interfaces can mobilize colloids. We visualized colloids interacting with moving air-water interfaces during capillary fringe fluctuations by confocal microscopy. We simulated capillary fringe fluctuations in a glass-bead-filled column. We studied four specific conditions: (1) colloids suspended in the aqueous phase, (2) colloids attached to the glass beads in an initially wet porous medium, (3) colloids attached to the glass beads in an initially dry porous medium, and (4) colloids suspended in the aqueous phase with the presence of a static air bubble. Confocal images confirmed that the capillary fringe fluctuations affect colloid transport behavior. Hydrophilic negatively charged colloids initially suspended in the aqueous phase were deposited at the solid-water interface after a drainage passage, but then were removed by subsequent capillary fringe fluctuations. The colloids that were initially attached to the wet or dry glass bead surface were detached by moving air-water interfaces in the capillary fringe. Hydrophilic negatively charged colloids did not attach to static air-bubbles, but hydrophobic negatively charged and hydrophilic positively charged colloids did. Our results demonstrate that capillary fringe fluctuations are an effective means for colloid mobilization.

  20. 41 CFR 302-10.400 - What policies must we establish for authorizing transportation of a mobile home?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... establish for authorizing transportation of a mobile home? 302-10.400 Section 302-10.400 Public Contracts... STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE... mobile home? You must establish policies for authorizing transportation of a mobile home that...

  1. Apollo 11 Occupied Mobile Quarantine Facility (MQF) Moved For Transport

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The Apollo 11 mission, the first manned lunar mission, launched from the Kennedy Space Center, Florida via the Marshall Space Flight Center (MSFC) developed Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. Aboard the space craft were astronauts Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. Aldrin Jr., Lunar Module (LM) pilot. The CM, piloted by Michael Collins remained in a parking orbit around the Moon while the LM, named 'Eagle'', carrying astronauts Neil Armstrong and Edwin Aldrin, landed on the Moon. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. The recovery operation took place in the Pacific Ocean where Navy para-rescue men recovered the capsule housing the 3-man Apollo 11 crew. The crew was airlifted to safety aboard the U.S.S. Hornet recovery ship, where they were quartered in a Mobile Quarantine Facility (MQF) which served as their home until they reached the NASA Manned Spacecraft Center (MSC) Lunar Receiving Laboratory in Houston, Texas. The occupied MQF was unloaded from the U.S.S. Hornet in Pearl Harbor, Hawaii. In this photo, the facility is moved from the Hornet's dock enroute to Hickam Field where it was loaded aboard an Air Force C-141 jet transport for the flight back to Ellington Air Force Base Texas, and then on to the MSC.

  2. 41 CFR 302-10.4 - Are there any geographic limitations for transportation of a mobile home?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... limitations for transportation of a mobile home? 302-10.4 Section 302-10.4 Public Contracts and Property...-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Eligibility and Limitations § 302-10.4 Are there any geographic limitations for transportation of a mobile home?...

  3. 41 CFR 302-10.4 - Are there any geographic limitations for transportation of a mobile home?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... limitations for transportation of a mobile home? 302-10.4 Section 302-10.4 Public Contracts and Property...-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Eligibility and Limitations § 302-10.4 Are there any geographic limitations for transportation of a mobile home?...

  4. 41 CFR 302-10.4 - Are there any geographic limitations for transportation of a mobile home?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... limitations for transportation of a mobile home? 302-10.4 Section 302-10.4 Public Contracts and Property...-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Eligibility and Limitations § 302-10.4 Are there any geographic limitations for transportation of a mobile home?...

  5. 41 CFR 302-10.4 - Are there any geographic limitations for transportation of a mobile home?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... limitations for transportation of a mobile home? 302-10.4 Section 302-10.4 Public Contracts and Property...-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Eligibility and Limitations § 302-10.4 Are there any geographic limitations for transportation of a mobile home?...

  6. 41 CFR 302-10.4 - Are there any geographic limitations for transportation of a mobile home?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... limitations for transportation of a mobile home? 302-10.4 Section 302-10.4 Public Contracts and Property...-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Eligibility and Limitations § 302-10.4 Are there any geographic limitations for transportation of a mobile home?...

  7. Helium jet dispersion to atmosphere

    NASA Astrophysics Data System (ADS)

    Khan, Hasna J.

    On the event of loss of vacuum guard of superinsulated helium dewar, high rate of heat transfer into the tank occurs. The rapid boiling of liquid helium causes the burst disk to rupture at four atmospheres and consequently the helium passes to the atmosphere through vent lines. The gaseous helium forms a vertical buoyant jet as it exits the vent line into a stagnant environment. Characterization of the gaseous jet is achieved by detailed analysis of the axial and radial dependence of the flow parameters.

  8. Assessment of a Regional Transportation Education Alliance To Improve Mobility.

    ERIC Educational Resources Information Center

    Kuhn, Beverly T.

    This report examines issues related to transportation education, with the objective of developing and packaging transportation-related materials for use in college and university transportation education programs. The study was conducted by the Southwest Region University Transportation Center (SWUTC) region, but it is expected that the results…

  9. Transportation and Aging: A Research Agenda for Advancing Safe Mobility

    ERIC Educational Resources Information Center

    Dickerson, Anne E.; Molnar, Lisa J.; Eby, David W.; Adler, Geri; Bedard, Michel; Berg-Weger, Marla; Classen, Sherrilene; Foley, Daniel; Horowitz, Amy; Kerschner, Helen; Page, Oliver; Silverstein, Nina M.; Staplin, Loren; Trujillo, Leonard

    2007-01-01

    Purpose: We review what we currently know about older driver safety and mobility, and we highlight important research needs in a number of key areas that hold promise for achieving the safety and mobility goals for the aging baby boomers and future generations of older drivers. Design and Methods: Through the use of a framework for transportation…

  10. Mobile bacteria and transport of polynuclear aromatic hydrocarbons in porous media

    SciTech Connect

    Jenkins, M.B.; Lion, L.W. )

    1993-10-01

    Sorption of hydrophobic pollutants such as polynuclear aromatic hydrocarbons (PAHs) to soil and aquifer materials can severely retard their mobility and the time course of their removal. Because mobile colloids may enhance the mobility of hydrophobic pollutants in porous media and indigenous bacteria are generally colloidal in size, bacterial isolates from soil and subsurface environments were tested for their ability to enhance the transport of phenanthrene, a model PAH, in aquifer sand. Batch isotherm experiments were performed to measure the ability of selected bacteria, including 14 isolates from a manufactured gas plant waste site, to sorb [sup 14]C-phenanthrene and to determine whether the presence of the suspended cells would reduce the distribution coefficient (K[sub d]) for phenanthrene with the sand. Column experiments were then used to test the mobility of isolates that reduced the K[sub d] for phenanthrene and to test the most mobile isolate for its ability to enhance the transport of phenanthrene. All of the isolates tested passively sorbed phenanthrene, and most but not all of the isolates reduced the K[sub d] for phenanthrene. Some, but not all, of those isolates were mobile in column experiments. The most mobile isolate significantly enhanced the transport of phenanthrene in aquifer sand, reducing its retardation coefficient by 25% at a cell concentration of [approximately]5 x 10[sup 7] ml[sup [minus]1]. The experimental results demonstrated that mobile bacteria may enhance the transport of PAHs in the subsurface.

  11. Mobile bacteria and transport of polynuclear aromatic hydrocarbons in porous media.

    PubMed Central

    Jenkins, M B; Lion, L W

    1993-01-01

    Sorption of hydrophobic pollutants such as polynuclear aromatic hydrocarbons (PAHs) to soil and aquifer materials can severely retard their mobility and the time course of their removal. Because mobile colloids may enhance the mobility of hydrophobic pollutants in porous media and indigenous bacteria are generally colloidal in size, bacterial isolates from soil and subsurface environments were tested for their ability to enhance the transport of phenanthrene, a model PAH, in aquifer sand. Batch isotherm experiments were performed to measure the ability of selected bacteria, including 14 isolates from a manufactured gas plant waste site, to sorb 14C-phenanthrene and to determine whether the presence of the suspended cells would reduce the distribution coefficient (Kd) for phenanthrene with the sand. Column experiments were then used to test the mobility of isolates that reduced the Kd for phenanthrene and to test the most mobile isolate for its ability to enhance the transport of phenanthrene. All of the isolates tested passively sorbed phenanthrene, and most but not all of the isolates reduced the Kd for phenanthrene. Some, but not all, of those isolates were mobile in column experiments. The most mobile isolate significantly enhanced the transport of phenanthrene in aquifer sand, reducing its retardation coefficient by 25% at a cell concentration of approximately 5 x 10(7) ml-1. The experimental results demonstrated that mobile bacteria may enhance the transport of PAHs in the subsurface. PMID:8250555

  12. Decreased Salinity and Actinide Mobility: Colloid-Facilitated Transport or pH Change?

    PubMed

    Haliena, Brian; Zheng, Hangping; Melson, Nathan; Kaplan, Daniel I; Barnett, Mark O

    2016-01-19

    Colloids have been implicated in influencing the transport of actinides and other adsorbed contaminants in the subsurface, significantly increasing their mobility. Such colloid-facilitated transport can be induced by changes in groundwater chemistry that occur, for example, when high ionic strength contaminant plumes are displaced by infiltrating rainwater. We studied the transport and mobility of Th(IV), as an analogue for Pu(IV) and other tetravalent actinides [An(IV)], in saturated columns packed with a natural heterogeneous subsurface sandy sediment. As expected, decreases in ionic strength both promoted the mobilization of natural colloids and enhanced the transport of previously adsorbed Th(IV). However, colloid-facilitated transport played only a minor role in enhancing the transport of Th(IV). Instead, the enhanced transport of Th(IV) was primarily due to the pH-dependent desorption of Th(IV) caused by the change in ionic strength. In contrast, the adsorption of Th(IV) had a marked impact on the surface charge of the sandy sediment, significantly affecting the mobility of the colloids. In the absence of Th(IV), changes in ionic strength were ineffective at releasing colloids while in the presence of Th(IV), decreases in ionic strength liberated significant concentrations of colloids. Therefore, under the conditions of our experiments which mimicked acidic, high ionic strength groundwater contaminant plumes, Th(IV) had a much greater effect on colloid transport than colloids had on Th(IV) transport.

  13. Transportation Electrification Education Partnership for Green Jobs and Sustainable Mobility

    SciTech Connect

    Peng, Huei; Mi, Chris; Gover, James

    2013-06-28

    This collaborative educational project between the University of Michigan—Ann Arbor, University of Michigan—Dearborn and the Kettering University successfully executed almost all the elements we proposed to do. In the original proposal, we proposed to develop four graduate courses, six undergraduate courses, four professional short courses, a K-12 electric vehicle education kit, a Saturday morning seminar series, and a set of consumer education material to support the advancement of transportation electrification. The first four deliverables were all successfully developed and offered. When we held the kick-off meeting in NETL in Morgantown back in early 2010 with all the ten ARRA education teams, however, it quickly became clear that among the ten ARRA education grantee teams, our proposed “consume education” activities are not better or with the potential to create bigger impact than some of activities proposed in other teams. For example, the Odyssey 2010 event held by the West Virginia University team had planned and successfully reached to more than 230,000 attendees, which is way more than what our proposed 100k event could ever reach. It was under the suggestion of Joseph Quaranta, the ARRA education Program Director at that time, that we should coordinate and eliminate redundancy. The resources should then be focused on activities that have less overlap. Therefore, the originally proposed activities: Saturday morning seminar series, and a set of consumer education material were dropped from our scope. We expanded the scope of our “education kit” activity to include some educational materials, mainly in the form of videos. The target audience also changed from general public to K-12 students. The majority of the project cost (~70%) goes toward the establishment of three undergraduate laboratories, which provides critically needed hands-on learning experience for next-generation green mobility engineers. We are very proud that the ARRA money

  14. Characterization of asymmetric electron and hole transport in a high-mobility semiconducting polymer

    NASA Astrophysics Data System (ADS)

    Wang, Liguo; Wang, Xinliang; Liu, Mengli; Cheng, Lingfei

    2017-01-01

    The electron and hole transport properties in a high-mobility n-type copolymer poly{[ N, N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diy1]-alt-5,5'-(2,2'-dithiophene)}[P(NDI2OD-T2), PolyeraActivInk™ N2200] are investigated. The electron mobility is observed to be more than two orders of magnitude higher than the hole mobility. The thickness-dependent current density versus voltage ( J- V) characteristics of N2200 electron-only and hole-only devices cannot be well described using the conventional mobility model. However, the thickness-dependent and temperature-dependent J- V characteristics of N2200 electron-only and hole-only devices can be accurately described using our recently introduced improved mobility model only with a single set of parameters. Within the improved model, the mobility depends on three important physical quantities: the temperature, carrier density, and electric field. For the semiconducting polymer studied, we find the width of the Gaussian density of states σ = 0.082 eV and the lattice constant a = 0.8 nm for electron transport, while the width of the Gaussian density of states σ = 0.11 eV and the lattice constant a = 0.8 nm for hole transport. It is clear that hole transport exhibits a significantly stronger disorder than electron transport. This is also reflected in the lower hole mobility, as compared to the electron mobility.

  15. Ion mobility and transport barriers in the tokamak plasmas

    SciTech Connect

    Xiao, H.; Hazeltine, R.D.; Valanju, P.M.; Zhang, Y.Z.

    1993-06-01

    The character of charged particle motion in an axisymmetric toroidal system with a constant radial electric field is investigated both analytically and numerically. Ion radial mobility caused by the combined effects of the radial electric field and charge exchange is found. A simple moment argument in the banana regime matches the simulation results well. Relation of present work and high confinement (H-mode) experiment is also discussed.

  16. Way-Finding Support in Public Transport Environments provided by the NAMO Mobile Travel Assistance System.

    PubMed

    Bühler, Christian; Heck, Helmut; Nietzio, Annika; Reins, Frank; Berker, Frank

    2015-01-01

    The NAMO travel assistance system is a mobile application providing support for elder travellers in public transport and on foot. The system combines technical and human support during the journey, especially in situations where many seniors experience orientation difficulties. Several approaches to way-finding and orientation support have been developed. This paper introduces the different approaches and presents the results of the extensive user evaluations, leading to recommendations for future development of mobile travel assistance applications for seniors.

  17. Theory of transport phenomena in polycrystalline lead chalcogenide films. Mobility. Nondegenerate statistics

    SciTech Connect

    Atakulov, Sh. B. Zaynolobidinova, S. M.; Nabiev, G. A.; Nabiyev, M. B.; Yuldashev, A. A.

    2013-07-15

    The mobility of nondegenerate electrons in quasi-single-crystal and polycrystalline PbTe films is experimentally investigated. The results obtained are compared with the data for bulk crystals at the same charge-carrier concentration. Under the assumption of limitation of the charge-carrier mobility by intercrystallite potential barriers, electron transport in an electric field is theoretically considered. The theoretical results are in good agreement with the experiment.

  18. Application of Fiber-Optical Techniques in the Access Transmission and Backbone Transport of Mobile Networks

    NASA Astrophysics Data System (ADS)

    Hilt, Attila; Pozsonyi, László

    2012-09-01

    Fixed access networks widely employ fiber-optical techniques due to the extremely wide bandwidth offered to subscribers. In the last decade, there has also been an enormous increase of user data visible in mobile systems. The importance of fiber-optical techniques within the fixed transmission/transport networks of mobile systems is therefore inevitably increasing. This article summarizes a few reasons and gives examples why and how fiber-optic techniques are employed efficiently in second-generation networks.

  19. Mobile Phone Use Behaviors and Postures on Public Transportation Systems

    PubMed Central

    Liang, Huey-Wen; Hwang, Yaw-Huei

    2016-01-01

    Mobile phones are common in our daily life, but the users’ preferences for postures or screen operating styles have not been studied. This was a cross-sectional and observational study. We randomly sampled passengers who used mobile phones on the Mass Rapid Transit (MRT) system in metropolitan Taipei. A checklist was used to observe their body postures and screen operating styles while sitting or standing. As a result, 1,230 subjects from 400 trips were observed. Overall, of all the passengers who were sitting, 41% of them were using mobile phones. The majority of the tasks involved browsing (84%) with their phones in a portrait orientation (93%). Different-hand holding/operating was the most commonly used operating style while sitting (46%) and same-hand holding/operating was the most common while standing (46%). The distribution of screen operating styles was significantly different for those sitting than for those standing and for different genders and age groups. The most frequently observed postures while sitting were having one’s trunk against a backrest, feet on the floor and with or without an arm supported (58%). As for the users who were standing, the both- and different-hands groups had a high proportion of arms unsupported, feet on the floor and either their trunk supported or not. In contrast, the same-hand group tended to have their trunk unsupported, were holding a pole or handstrap and had both feet on floor. Further studies are warranted to characterize the ergonomic exposure of these commonly used postures and operating styles, and our results will help guide the selection of experimental conditions for laboratory settings. PMID:26828797

  20. Enhancing Transportation Education Using Mobile Devices and Applications

    ERIC Educational Resources Information Center

    Gallup, Jennifer; Lamothe, Saron N.; Gallup, Adam

    2015-01-01

    The most salient aspect of independent living and successful post-high school transition to employment is having the ability to independently use transportation. Adolescents and young adults with disabilities continue to experience significantly lower employment rates than their peers without disabilities (Wagner et al., 2003). One way to support…

  1. Plant Rhizosphere Effects on Metal Mobilization and Transport

    SciTech Connect

    Fan, Teresa W.-M; Crowley, David; Higashi, Richard M.

    1999-06-01

    A mechanistic understanding of mobilization or immobilization of nutrient and pollutant metal ions by plants is largely lacking. It begins with a lack of knowledge on the chemical nature of rhizosphere components that are reactive with metal ions. This fundamental knowledge is critical to the design and implementation of phytoremediation for metal-contaminated DOE sites. Therefore, the objectives of this project include (1) To obtain a comprehensive composition of major organic components in plant root exudates as a function of different metal ions and plant species; (2) To examine plant metabolic response(s) to these metal ion treatments, with emphasis on production of metal reactive compounds; (3) To investigate the effect(s) of soil microbial (e.g. mycorrhizae) association on (1) and (2).

  2. The Sustainable Mobility Learning Laboratory: Interactive Web-Based Education on Transportation and the Environment

    ERIC Educational Resources Information Center

    Schweitzer, Lisa A.; Marr, Linsey C.; Linford, John C.; Darby, Mary Ashburn

    2008-01-01

    The transportation field has for many years been dominated by engineers and other technical specialists. This article describes the Sustainable Mobility Learning Lab (SMLL), a Web-based tool designed to support classroom and university outreach activities to help initiate a more inclusive, nontechnical discussion about the role of transportation…

  3. 41 CFR 302-10.402 - What costs must we pay a commercial carrier for transporting a mobile home?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false What costs must we pay a commercial carrier for transporting a mobile home? 302-10.402 Section 302-10.402 Public Contracts and... Responsibilities § 302-10.402 What costs must we pay a commercial carrier for transporting a mobile home? The...

  4. 41 CFR 302-10.402 - What costs must we pay a commercial carrier for transporting a mobile home?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 4 2013-07-01 2012-07-01 true What costs must we pay a commercial carrier for transporting a mobile home? 302-10.402 Section 302-10.402 Public Contracts and... Responsibilities § 302-10.402 What costs must we pay a commercial carrier for transporting a mobile home? The...

  5. 41 CFR 302-10.400 - What policies must we establish for authorizing transportation of a mobile home?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false What policies must we establish for authorizing transportation of a mobile home? 302-10.400 Section 302-10.400 Public Contracts... responsibility for preparing and transporting an employee's mobile home; (b) To authorize an advance of funds...

  6. 41 CFR 302-10.1 - May I be reimbursed for transporting my mobile home instead of an HHG shipment?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false May I be reimbursed for transporting my mobile home instead of an HHG shipment? 302-10.1 Section 302-10.1 Public Contracts and Property... Limitations § 302-10.1 May I be reimbursed for transporting my mobile home instead of an HHG shipment? Yes,...

  7. COLLOID MOBILIZATION AND TRANSPORT IN CONTAMINANT PLUMES: FIELD EXPERIMENTS, LABORATORY EXPERIMENTS, AND MODELING (EPA/600/S-99/001)

    EPA Science Inventory

    The major hypothesis driving this research, that the transport of colloids in a contaminant plume is limited by the advance of the chemical agent causing colloid mobilization, was tested by (1) examining the dependence of colloid transport and mobilization on chemical perturbatio...

  8. Carrier transport in high mobility InAs nanowire junctionless transistors.

    PubMed

    Konar, Aniruddha; Mathew, John; Nayak, Kaushik; Bajaj, Mohit; Pandey, Rajan K; Dhara, Sajal; Murali, K V R M; Deshmukh, Mandar M

    2015-03-11

    The ability to understand and model the performance limits of nanowire transistors is the key to the design of next generation devices. Here, we report studies on high-mobility junctionless gate-all-around nanowire field effect transistor with carrier mobility reaching 2000 cm(2)/V·s at room temperature. Temperature-dependent transport measurements reveal activated transport at low temperatures due to surface donors, while at room temperature the transport shows a diffusive behavior. From the conductivity data, the extracted value of sound velocity in InAs nanowires is found to be an order less than the bulk. This low sound velocity is attributed to the extended crystal defects that ubiquitously appear in these nanowires. Analyzing the temperature-dependent mobility data, we identify the key scattering mechanisms limiting the carrier transport in these nanowires. Finally, using these scattering models, we perform drift-diffusion based transport simulations of a nanowire field-effect transistor and compare the device performances with experimental measurements. Our device modeling provides insight into performance limits of InAs nanowire transistors and can be used as a predictive methodology for nanowire-based integrated circuits.

  9. Polymer Thin Film Transistors: High Electron Mobility and Ambipolar Charge Transport

    NASA Astrophysics Data System (ADS)

    Jenekhe, Samson; Babel, Amit

    2004-03-01

    Along with high performance unipolar FETs, knowledge of ambipolar charge transport in conjugated polymers and organic semiconductors is important to realize the ultimate vision of all-plastic complementary integrated circuits for logic and memory applications. We present herein studies of electron transport in n-type conjugated ladder polymer, poly(benzobisimidazobenzophenanthroline) (BBL) in which we observed field-effect electron mobilities as high as 0.05-0.1 cm^2/Vs.^[1] We have also developed new ambipolar thin film transistors based on blends of BBL and copper phthalocyanine (CuPc). Ambipolar hole mobilities were as high as 2.0 × 10-4 cm^2/Vs while electron mobilities were up to 3.0 × 10-5 cm^2/Vs. Transmission electron microscopy showed crystallization of CuPc in the α -crystal form within the semicrystalline BBL matrix. On prolonged treatment of the blend FETs in methanol, unipolar hole mobilities as high as 2.0 × 10-3 cm^2/Vs were observed, comparable to hole mobilities in thermally evaporated CuPc FETs. [1] Babel, A.; Jenekhe, S. A. J. Am. Chem. Soc. 2003, 125, 13656.

  10. AllAboard: Visual Exploration of Cellphone Mobility Data to Optimise Public Transport.

    PubMed

    Di Lorenzo, G; Sbodio, M; Calabrese, F; Berlingerio, M; Pinelli, F; Nair, R

    2016-02-01

    The deep penetration of mobile phones offers cities the ability to opportunistically monitor citizens' mobility and use data-driven insights to better plan and manage services. With large scale data on mobility patterns, operators can move away from the costly, mostly survey based, transportation planning processes, to a more data-centric view, that places the instrumented user at the center of development. In this framework, using mobile phone data to perform transit analysis and optimization represents a new frontier with significant societal impact, especially in developing countries. In this paper we present AllAboard, an intelligent tool that analyses cellphone data to help city authorities in visually exploring urban mobility and optimizing public transport. This is performed within a self contained tool, as opposed to the current solutions which rely on a combination of several distinct tools for analysis, reporting, optimisation and planning. An interactive user interface allows transit operators to visually explore the travel demand in both space and time, correlate it with the transit network, and evaluate the quality of service that a transit network provides to the citizens at very fine grain. Operators can visually test scenarios for transit network improvements, and compare the expected impact on the travellers' experience. The system has been tested using real telecommunication data for the city of Abidjan, Ivory Coast, and evaluated from a data mining, optimisation and user prospective.

  11. Results of EVA/mobile transporter space station truss assembly tests

    NASA Technical Reports Server (NTRS)

    Watson, Judith J.; Heard, Walter L., Jr.; Bush, Harold G.; Lake, M. S.; Jensen, J. K.; Wallsom, R. E.; Phelps, J. E.

    1988-01-01

    Underwater neutral buoyance tests were conducted to evaluate the use of a Mobile Transporter concept in conjunction with EVA astronauts to construct the Space Station Freedom truss structure. A three-bay orthogonal tetrahedral truss configuration with a 15 foot square cross section was repeatedly assembled by a single pair of pressure suited test subjects working from the Mobile Transporter astronaut positioning devices (mobile foot restraints). The average unit assembly time (which included integrated installation of utility trays) was 27.6 s/strut, or 6 min/bay. The results of these tests indicate that EVA assembly of space station size structures can be significantly enhanced when using a Mobile Transporter equipped with astronaut positioning devices. Rapid assembly time can be expected and are dependent primarily on the rate of translation permissible for on-orbit operations. The concept used to demonstate integrated installation of utility trays requires minimal EVA handling and consequentially, as the results show, has little impact on overall assembly time.

  12. Explaining the power-law distribution of human mobility through transportation modality decomposition.

    PubMed

    Zhao, Kai; Musolesi, Mirco; Hui, Pan; Rao, Weixiong; Tarkoma, Sasu

    2015-03-16

    Human mobility has been empirically observed to exhibit Lévy flight characteristics and behaviour with power-law distributed jump size. The fundamental mechanisms behind this behaviour has not yet been fully explained. In this paper, we propose to explain the Lévy walk behaviour observed in human mobility patterns by decomposing them into different classes according to the different transportation modes, such as Walk/Run, Bike, Train/Subway or Car/Taxi/Bus. Our analysis is based on two real-life GPS datasets containing approximately 10 and 20 million GPS samples with transportation mode information. We show that human mobility can be modelled as a mixture of different transportation modes, and that these single movement patterns can be approximated by a lognormal distribution rather than a power-law distribution. Then, we demonstrate that the mixture of the decomposed lognormal flight distributions associated with each modality is a power-law distribution, providing an explanation to the emergence of Lévy Walk patterns that characterize human mobility patterns.

  13. Explaining the power-law distribution of human mobility through transportation modality decomposition

    PubMed Central

    Zhao, Kai; Musolesi, Mirco; Hui, Pan; Rao, Weixiong; Tarkoma, Sasu

    2015-01-01

    Human mobility has been empirically observed to exhibit Lévy flight characteristics and behaviour with power-law distributed jump size. The fundamental mechanisms behind this behaviour has not yet been fully explained. In this paper, we propose to explain the Lévy walk behaviour observed in human mobility patterns by decomposing them into different classes according to the different transportation modes, such as Walk/Run, Bike, Train/Subway or Car/Taxi/Bus. Our analysis is based on two real-life GPS datasets containing approximately 10 and 20 million GPS samples with transportation mode information. We show that human mobility can be modelled as a mixture of different transportation modes, and that these single movement patterns can be approximated by a lognormal distribution rather than a power-law distribution. Then, we demonstrate that the mixture of the decomposed lognormal flight distributions associated with each modality is a power-law distribution, providing an explanation to the emergence of Lévy Walk patterns that characterize human mobility patterns. PMID:25779306

  14. Explaining the power-law distribution of human mobility through transportation modality decomposition

    NASA Astrophysics Data System (ADS)

    Zhao, Kai; Musolesi, Mirco; Hui, Pan; Rao, Weixiong; Tarkoma, Sasu

    2015-03-01

    Human mobility has been empirically observed to exhibit Lévy flight characteristics and behaviour with power-law distributed jump size. The fundamental mechanisms behind this behaviour has not yet been fully explained. In this paper, we propose to explain the Lévy walk behaviour observed in human mobility patterns by decomposing them into different classes according to the different transportation modes, such as Walk/Run, Bike, Train/Subway or Car/Taxi/Bus. Our analysis is based on two real-life GPS datasets containing approximately 10 and 20 million GPS samples with transportation mode information. We show that human mobility can be modelled as a mixture of different transportation modes, and that these single movement patterns can be approximated by a lognormal distribution rather than a power-law distribution. Then, we demonstrate that the mixture of the decomposed lognormal flight distributions associated with each modality is a power-law distribution, providing an explanation to the emergence of Lévy Walk patterns that characterize human mobility patterns.

  15. High-Mobility Transport Anisotropy in Few-Layer MoO3 and Its Origin.

    PubMed

    Zhang, Wei-Bing; Qu, Qian; Lai, Kang

    2017-01-18

    The novel two-dimensional semiconductors with high carrier mobility and excellent stability are essential to the next-generation high-speed and low-power nanoelectronic devices. Because of the natural abundance, intrinsic gap, and chemical stability, metal oxides were also recently suggested as potential candidates for electronic materials. However, their carrier mobilities are typically on the order of tens of square centimeters per volt per second, much lower than that for commonly used silicon. By using first-principles calculations and deformation potential theory, we have predicted few-layer MoO3 as chemically stable wide-band-gap semiconductors with a considerably high acoustic-phonon-limited carrier mobility above 3000 cm(2) V(-1) s(-1), which makes them promising candidates for both electron- and hole-transport applications. Moreover, we also find a large in-plane anisotropy of the carrier mobility with a ratio of about 20-30 in this unusual system. Further analysis indicates that, because of the unique charge density distribution of whole valence electrons and the states near the band edge, both the elastic modulus and deformation potential are strongly directionally dependent. Also, the predicted high-mobility transport anisotropy of few-layer MoO3 can be attributed to the synergistic effect of the anisotropy of the elastic modulus and deformation potential. Our results not only give an insightful understanding for the high carrier mobility observed in few-layer MoO3 systems but also reveal the importance of the carrier-transport direction to the device performance.

  16. Impact of Mobile-Immoble Water on the Transport of Technetium (Tc-99) in Unsaturated Sediments

    NASA Astrophysics Data System (ADS)

    Jansik, D. P.; Wellman, D. M.; Cordova, E.; Wildenschild, D.

    2010-12-01

    Technetium has been released to the environment through nuclear power production and nuclear fuel processing; as a result, further spreading of Tc-99 is a concern at DOE sites across the US. The current body of work conducted on Tc-99 has provided a wealth of information regarding the redox relationships, sorption, solubility, and stability of the mineral phases, however little work has been conducted on the physical transport of the highly soluble pertechnetate oxyanion, in the subsurface. Current conceptual models do not explain the presence and persistence of the anion in deep vadose zone environments such as the Hanford, WA site. As new in situ remediation technologies are developed and remediation continues; it is necessary to understand implications for Tc-99 transport and mobilization in unsaturated systems. Specifically, foam and gas phase remediation could potentially alter established flow regimes by changing moisture content, flow paths, and surface reactivity of sediments; therefore, it is imperative to understand fundamental transport properties of Tc-99 in the context of physical and chemical constraints. Using an Unsaturated Flow Apparatus (UFA) we have conducted a series of experiments to examine the impact of mobile-immobile domains on the transport of Tc-99. By varying sand/silt ratios and saturations we examined how changes in pore morphology and moisture content impact the transport of Tc-99 within our experimental system. Results demonstrating the impact of sediment texture, pore morphology and soil moisture content on Tc-99 transport will be presented.

  17. In situ mobilization of colloids and transport of cesium in Hanford sediments.

    PubMed

    Flury, Markus; Mathison, Jon B; Harsh, James B

    2002-12-15

    Radioactive waste, accumulated during Pu production, has leaked into the subsurface from underground storage tanks at the U.S. Department of Energy's Hanford site. The leaking solutions contained 137Cs and were of high ionic strength. Such a tank leak was simulated experimentally in steady-state flow experiments with packed Hanford sediments. The initial leak was simulated by a 1 M NaNO3 solution, followed by a decrease of ionic strength to 1 mM NaNO3. Cesium breakthrough curves were determined in both 1 M and 1 mM NaNO3 background. Colloidal particles were mobilized during the change of ionic strength. Mobilized colloids consisted mainly of quartz, mica, illite, kaolinite, and chlorite. Electrophoretic mobilities of colloids in the eluent solution were -3(microm/s)(V/cm) and increased to less negative values during later stages of mobilization. Mobilized colloids carried a fraction of the cesium along. While transport of cesium in 1 M NaNO3 background was much faster than in 1 mM NaNO3, cesium attached to colloids moved almost unretarded through the sediments. Cesium attached to mobilized colloids was likely associated with high affinity sorption sites on micas and illites.

  18. Tuning carrier mobility without spin transport degrading in copper-phthalocyanine

    SciTech Connect

    Jiang, S. W.; Wang, P.; Chen, B. B.; Zhou, Y.; Ding, H. F. E-mail: dwu@nju.edu.cn; Wu, D. E-mail: dwu@nju.edu.cn

    2015-07-27

    We demonstrate more than one order of magnitude of carrier mobility tuning for the copper-phthalocyanine (CuPc) without spin transport degrading in organic spin valve devices. Depending on the preparation conditions, organic spin valves with the CuPc film mobility of 5.78 × 10{sup −3} and 1.11 × 10{sup −4} cm{sup 2}/V s are obtained for polycrystalline and amorphous CuPc, respectively. Strikingly, the spin diffusion lengths are almost the same regardless of their mobilities that are ∼50 times different, which is in sharp contrast with previous prediction. These findings directly support that the spin relaxation in CuPc is dominated by the spin-orbit coupling.

  19. 41 CFR 302-10.202 - Am I entitled to any other allowances when I transport my mobile home by POV?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... other allowances when I transport my mobile home by POV? 302-10.202 Section 302-10.202 Public Contracts... STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Computation of Allowances § 302-10.202 Am I entitled to any other allowances when I transport my mobile...

  20. Mobilization and Transport of Organic Compounds from Reservoir Rock and Caprock in Geological Carbon Sequestration Sites

    SciTech Connect

    Zhong, Lirong; Cantrell, Kirk J.; Mitroshkov, Alexandre V.; Shewell, Jesse L.

    2014-05-06

    Supercritical CO2 (scCO2) is an excellent solvent for organic compounds, including benzene, toluene, ethyl-benzene, and xylene (BTEX), phenols, and polycyclic aromatic hydrocarbons (PAHs). Monitoring results from geological carbon sequestration (GCS) field tests has shown that organic compounds are mobilized following CO2 injection. Such results have raised concerns regarding the potential for groundwater contamination by toxic organic compounds mobilized during GCS. Knowledge of the mobilization mechanism of organic compounds and their transport and fate in the subsurface is essential for assessing risks associated with GCS. Extraction tests using scCO2 and methylene chloride (CH2Cl2) were conducted to study the mobilization of volatile organic compounds (VOCs, including BTEX), the PAH naphthalene, and n-alkanes (n-C20 – n-C30) by scCO2 from representative reservoir rock and caprock obtained from depleted oil reservoirs and coal from an enhanced coal-bed methane recovery site. More VOCs and naphthalene were extractable by scCO2 compared to the CH2Cl2 extractions, while scCO2 extractable alkane concentrations were much lower than concentrations extractable by CH2Cl2. In addition, dry scCO2 was found to extract more VOCs than water saturated scCO2, but water saturated scCO2 mobilized more naphthalene than dry scCO2. In sand column experiments, moisture content was found to have an important influence on the transport of the organic compounds. In dry sand columns the majority of the compounds were retained in the column except benzene and toluene. In wet sand columns the mobility of the BTEX was much higher than that of naphthalene. Based upon results determined for the reservoir rock, caprock, and coal samples studied here, the risk to aquifers from contamination by organic compounds appears to be relatively low; however, further work is necessary to fully evaluate risks from depleted oil reservoirs.

  1. The design and development of a mobile transporter system for the Space Station Remote Manipulator System

    NASA Technical Reports Server (NTRS)

    Carroll, Thomas W.

    1987-01-01

    The analyses, selection process, and conceptual design of potential candidate Mobile Transporter (MT) systems to move the Space Station Remote Manipulator System (SSRMS) about the exposed faces of the Space Station truss structure are described. The actual requirements for a manipulator system on the space station are discussed, including potential tasks to be performed. The SSRMS operating environment and control methods are analyzed with potential design solutions highlighted. Three general categories of transporter systems are identified and analyzed. Several design solution have emerged that will satisfy these requirements. Their relative merits are discussed, and unique variations in each system are rated for functionality.

  2. Hydrologic Controls on Dissolved Organic Matter Mobilization and Transport within Undisturbed Soils

    NASA Astrophysics Data System (ADS)

    Xu, N.; Saiers, J.

    2007-12-01

    Dissolved organic matter (DOM) in soils plays an important role in the transport of nutrients and contaminants through the terrestrial environment. Subsurface pathways deliver a significant portion of carbon to streams that drain forested and agricultural watersheds. Although the importance of rainfall events to the DOM soil-water flux is well known, the hydrologic factors that govern this flux have not been fully examined. The primary purpose of this study is to investigate the soil and rainfall characteristics controlling the mobilization and transport of DOM in undisturbed soils. Intact soil columns including topsoil and subsoil layers were taken from the Harvard forest in Petersham, MA. Unsaturated flow conditions were maintained by applying suction to the bottom of the soil columns. The columns were irrigated by series of interrupted rainfall events using the same total volume of artificial rain water. Preliminary experiments showed continuous leaching of DOM (measured by dissolved organic carbon) with an initial peak in concentration that coincided with the passage of the wetting front. The leached DOM was also characterized by UV absorbance, fluorescence spectroscopy in the emission mode, and additional spectroscopic derived indexes such as the humification index. Ongoing column experiments are focusing on the effects of rainfall intensity, frequency, and rainfall history on DOM mobilization and transport through natural, structured soils. These investigations can elucidate the influence of factors that are associated with climate change on DOC dynamics. Results of our analyses should also provide insight into the mechanisms that govern DOM mobilization in soils.

  3. Charge transport and mobility engineering in two-dimensional transition metal chalcogenide semiconductors.

    PubMed

    Li, Song-Lin; Tsukagoshi, Kazuhito; Orgiu, Emanuele; Samorì, Paolo

    2016-01-07

    Two-dimensional (2D) van der Waals semiconductors represent the thinnest, air stable semiconducting materials known. Their unique optical, electronic and mechanical properties hold great potential for harnessing them as key components in novel applications for electronics and optoelectronics. However, the charge transport behavior in 2D semiconductors is more susceptible to external surroundings (e.g. gaseous adsorbates from air and trapped charges in substrates) and their electronic performance is generally lower than corresponding bulk materials due to the fact that the surface and bulk coincide. In this article, we review recent progress on the charge transport properties and carrier mobility engineering of 2D transition metal chalcogenides, with a particular focus on the markedly high dependence of carrier mobility on thickness. We unveil the origin of this unique thickness dependence and elaborate the devised strategies to master it for carrier mobility optimization. Specifically, physical and chemical methods towards the optimization of the major factors influencing the extrinsic transport such as electrode/semiconductor contacts, interfacial Coulomb impurities and atomic defects are discussed. In particular, the use of ad hoc molecules makes it possible to engineer the interface with the dielectric and heal the vacancies in such materials. By casting fresh light on the theoretical and experimental studies, we provide a guide for improving the electronic performance of 2D semiconductors, with the ultimate goal of achieving technologically viable atomically thin (opto)electronics.

  4. Hall effect and band-like carrier transport in high mobility polymer transistors

    NASA Astrophysics Data System (ADS)

    Yamashita, Yu; Hinkel, Felix; Marszalek, Tomasz; Zajaczkowski, Wojciech; Pisula, Wojciech; Baumgarten, Martin; Matsui, Hiroyuki; Müllen, Klaus; Takeya, Jun; Takeya Group Team, Prof.; Müllen Group Team, Prof.

    A microscopic understanding of charge carrier transport in polymeric semiconductors is essential to improve the state of the art of flexible or printed electronic devices. In particular, thin-film field-effect transistors based on donor-acceptor polymers are in the focus of current literature reaching high charge-carrier mobility. In this work, we demonstrate the Hall effect and the temperature dependence of the charge carrier mobility based on uniaxially ordered CDT-BTZ donor-acceptor copolymer films. Uniaxially ordered films of CDT-BTZ with hexadecyl (C16) and eicosyl (C20) sidechains showed mobility of 5.6 cm2/Vs and 11.4 cm2/Vs respectively. The activation energy of the mobility decreased with the increasing carrier density, and finally the negative temperature dependence of the mobility was observed. Both polymers showed Hall effect, which also indicates the presence of extended electronic states. The temperature and carrier density dependence will be further discussed in the presentation.

  5. Organic Carbon Transport through Holocene and Pleistocene Sediment from Southeast Asia: Implications for Arsenic Mobilization

    NASA Astrophysics Data System (ADS)

    Stanimirova, R.; Mailloux, B. J.; Sun, J.; Bostick, B. C.; Mulvihill, C.; van Geen, A.; Mihajlov, I.; Magyar, J. S.; Ahmed, K.; Choudhury, I.; Stute, M.

    2013-12-01

    The oxidation of organic carbon coupled to the reduction of Fe (hydr)oxides is causing the mobilization of arsenic from sediment to groundwater in Southeast Asia and has resulted in a public health crisis. Recent results indicate that advected organic carbon could be a primary source of the reactive OC to the subsurface. Little is known about OC transport through aquifer sediments and its impact on aquifer geochemistry. The goal of this work was to perform column experiments using intact sediments from Holocene and Pleistocene drinking water aquifers of Southeast Asia in which unreactive OC, Eliot soil Humic Acid (ESHA), was flushed through the column and effluent geochemistry was monitored. In field-run columns flushed with anaerobic site groundwater and no ESHA, As, Fe, and Mn aqueous concentrations remained constant or decreased with flushing, indicating that redox reactions were not occurring within the columns and these elements appear to just be slowly mobilized and flushed from the sediment. In anaerobic laboratory run columns with ESHA a large range of redox responses occurred. In site F sediment complete breakthrough of ESHA occurred within 5 PV and Mn reduction occurred during the injection of ESHA, but no response of Fe and As occurred, indicating flushing of these elements. In site K sediment, complete breakthrough of ESHA occurred in 20 PV and redox reactions occurred with increases in concentration of As, Fe, and Mn, indicating that the in situ microbial population was stimulated. In Cambodian Pleistocene sediment ESHA breakthrough occurred with bromide breakthrough and no redox reactions were observed and only flushing occurred. Fluorescence analysis indicates that the ESHA mobilized in situ sediment OC during initial breakthrough in each column. These results indicate that OC can be transported through Bangladesh sediments, but that more interactions between ESHA and the sediment result in more redox reactions and As mobilization and it is this

  6. 41 CFR 302-10.6 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses... Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Eligibility...

  7. 41 CFR 302-10.6 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses... Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Eligibility...

  8. 41 CFR 302-10.401 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses... Property Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE...

  9. 41 CFR 302-10.6 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses... Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Eligibility...

  10. 41 CFR 302-10.401 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses... Property Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE...

  11. 41 CFR 302-10.6 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses... Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE Eligibility...

  12. 41 CFR 302-10.401 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses... Property Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE...

  13. 41 CFR 302-10.401 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses... Property Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 10-ALLOWANCES FOR TRANSPORTATION OF MOBILE HOMES AND BOATS USED AS A PRIMARY RESIDENCE...

  14. Transport of Organic Contaminants Mobilized from Coal through Sandstone Overlying a Geological Carbon Sequestration Reservoir

    SciTech Connect

    Zhong, Lirong; Cantrell, Kirk J.; Bacon, Diana H.; Shewell, Jesse L.

    2014-02-01

    Column experiments were conducted using a wetted sandstone rock installed in a tri-axial core holder to study the flow and transport of organic compounds mobilized by scCO2 under simulated geologic carbon storage (GCS) conditions. The sandstone rock was collected from a formation overlying a deep saline reservoir at a GCS demonstration site. Rock core effluent pressures were set at 0, 500, or 1000 psig and the core temperature was set at 20 or 50°C to simulate the transport to different subsurface depths. The concentrations of the organic compounds in the column effluent and their distribution within the sandstone core were monitored. Results indicate that the mobility though the core sample was much higher for BTEX compounds than for naphthalene. Retention of organic compounds from the vapor phase to the core appeared to be primarily controlled by partitioning from the vapor phase to the aqueous phase. Adsorption to the surfaces of the wetted sandstone was also significant for naphthalene. Reduced temperature and elevated pressure resulted in greater partitioning of the mobilized organic contaminants into the water phase.

  15. Release and transport of mobile organic matter and biocolloids: A combined physicochemical and microbiological study

    NASA Astrophysics Data System (ADS)

    Reichel, Katharina; Schaefer, Sabine; Babin, Doreen; Smalla, Konny; Totsche, Kai Uwe

    2016-04-01

    Biogeochemical interfaces within the aggregate system of soils are "hot spots" of microbial activity and turnover of organic matter. We explore turnover, release and transport of mobile organic matter (MOM), micro-organisms (bio-colloids) and organo-mineral associations using a novel experimental approach employing two-layer columns experiment with matured soil under unsaturated flow conditions. The top layer was spiked with phenanthrene as a tracer for studying the decomposer communities involved in the decomposition of aromatic compounds that derive from lignin in natural systems. Columns were irrigated with artificial rain water with several flow interrupts of different durations. Physicochemical and chemical parameters as well as the microbial community composition were analysed in effluent samples and in soil slices. Release of MOM from the columns was in general controlled by non-equilibrium. Export of total and dissolved organic matter differed significantly in response to the flow interrupts. Effluent comprised organic and organo-mineral components as well as vital competent cells. By molecular biological methods we were even able to show that bacterial consortia exported are rather divers. Depth distribution of the bacterial communities associated with the immobile solid phase indicated high similarities in bacterial communities of the different depth layers and treatments. According to phenanthrene high affinity to the immobile phases, only a small fraction was subject to downstream transport with a strong decrease of the amount residing at the solid phase Our experiments directly prove that intact and competent microorganisms and even communities can be transported under unsaturated flow conditions. Moreover, we found that the dominant carbon source will impact not only the activity of specific microbial taxa but also their mobilization and transport. While total contribution of microbial organism to the mobile organic matter pool seems to be small, the

  16. Compact Layer Free Perovskite Solar Cells with a High-Mobility Hole-Transporting Layer.

    PubMed

    Zhu, Qianqian; Bao, Xichang; Yu, Jianhua; Zhu, Dangqiang; Qiu, Meng; Yang, Renqiang; Dong, Lifeng

    2016-02-03

    A high-mobility diketopyrrolopyrrole-based copolymer (P) was employed in compact layer free CH3NH3PbI3 perovskite solar cells as a hole-transporting layer (HTL). By using the P-HTL, the 6.62% device efficiency with conventional poly-3-hexylthiophene was increased to 10.80% in the simple device configuration (ITO/CH3NH3PbI3/HTL/MoO3/Ag). With improved short circuit current density, open circuit voltage, and fill factor, the higher power conversion efficiency of P-HTL device is ascribed to the higher carrier mobility, more suitable energy level, and lower interfacial charge recombination. Advantages of applying P-HTL to perovskite solar cells, such as low cost, low-temperature processing, and excellent performance with simple cell structure, exhibit a possibility for commercial applications.

  17. Coarse-grained quantum transport simulation for analyzing leakage-mobility antagonism in GNRFET

    NASA Astrophysics Data System (ADS)

    Ito, Masakatsu; Sato, Shintaro; Yokoyama, Naoki; Joachim, Christian; Green Nanoelectronics Center Team; CEMES-CNRS and Mana Satellite Collaboration

    2013-03-01

    Since it became clear that graphene transistors based on the classical MOSFET principle suffer from serious performance problems, researchers have explored new graphene device design using quantum transport simulations. A first-principle quantum transport simulation, however, still takes unaffordable computational cost to deal with a realistic size of graphene transistor (>104 atoms). This motivated us to import ESQC (elastic scattering quantum chemistry) technique from the research field of molecular electronics and to develop its coarse-grained version. To eliminate the atomic scale details, we reformulated ESQC technique using the continuum limit description of graphene charge carriers, which is given by the massless Dirac equation. Since the potential function in this Dirac equation is electrostatic potential distribution, it can be obtained from Poisson equation with the boundary conditions of gate voltages in a self-consistent manner. We are now applying this coarse-grained quantum transport simulation to GNRFETs (graphene nanoribbon field effect transistors) for resolving the mobility-leakage antagonism, where opening a bandgap in a graphene channel improves its switching ability but at the same time deteriorates the electron channel mobility.

  18. Entrainment, motion, and deposition of coarse particles transported by water over a sloping mobile bed

    NASA Astrophysics Data System (ADS)

    Heyman, J.; Bohorquez, P.; Ancey, C.

    2016-10-01

    In gravel bed rivers, bed load transport exhibits considerable variability in time and space. Recently, stochastic bed load transport theories have been developed to address the mechanisms and effects of bed load transport fluctuations. Stochastic models involve parameters such as particle diffusivity, entrainment, and deposition rates. The lack of hard information on how these parameters vary with flow conditions is a clear impediment to their application to real-world scenarios. In this paper, we determined the closure equations for the above parameters from laboratory experiments. We focused on shallow supercritical flow on a sloping mobile bed in straight channels, a setting that was representative of flow conditions in mountain rivers. Experiments were run at low sediment transport rates under steady nonuniform flow conditions (i.e., the water discharge was kept constant, but bed forms developed and migrated upstream, making flow nonuniform). Using image processing, we reconstructed particle paths to deduce the particle velocity and its probability distribution, particle diffusivity, and rates of deposition and entrainment. We found that on average, particle acceleration, velocity, and deposition rate were responsive to local flow conditions, whereas entrainment rate depended strongly on local bed activity. Particle diffusivity varied linearly with the depth-averaged flow velocity. The empirical probability distribution of particle velocity was well approximated by a Gaussian distribution when all particle positions were considered together. In contrast, the particles located in close vicinity to the bed had exponentially distributed velocities. Our experimental results provide closure equations for stochastic or deterministic bed load transport models.

  19. The versatility of a truss mounted mobile transporter for in-space construction

    NASA Technical Reports Server (NTRS)

    Bush, Harold G.; Lake, Mark S.; Watson, Judith J.; Heard, Walter L., Jr.

    1988-01-01

    The Mobile Transporter (MT) evolution from early erectable structures assembly activities is detailed. The MT operational features which are required to support astronauts performing on-orbit structure construction or spacecraft assembly functions are presented and discussed. Use of the MT to perform a variety of assembly functions is presented. Estimated EVA assembly times for a precision segmented reflector approximately 20 m in diameter are presented. The EVA/MT technique under study for construction of the reflector (and the entire spacecraft) is illustrated. Finally, the current status of development activities and test results involving the MT and Space Station structural assembly are presented.

  20. Cooperating Mobile GIS and Wireless Sensor Networks for Managing Transportation Infrastructures in Urban areas

    NASA Astrophysics Data System (ADS)

    Shad, R.; Abazari, N.; Alizadeh, A.; Choghooni, M.

    2013-10-01

    Time management is a major subject which, in order to optimize trip conditions, emphasizes on interpreting processes and classifying individual's information. In this paper, with the aim of providing an optimal system for urban commuting in proper time in Mashhad, each user using SMS and introducing some of his/her mental priorities to the system, will be able to select the best option depending on the timing of movement of the available public transport system. The present study adopts a newly developed method of time management which is evaluated for urban transportation considering dynamic conditions of a spatial database. For this purpose, regarding time management, processed data such as bus lines, taxi networks, and the subway system are combined in a spatial framework of a designed Mobile GIS based on a wireless network. So, multiple potential paths which end to a desirable destination.

  1. [Mobile intensive-care-unit for transportation of premature and newborn babies at risc (author's transl)].

    PubMed

    Wille, L; Obladen, M; Schlunk, P; Weisser, J

    1975-02-01

    This is a technical report on a specially equipped ambulance for transportation of high-risk, seriously ill neonates. A mobile neonatal intensive-care-unit operating independently of the car utilized an Ohio-transport-incubator with 12V-DC portable power pak and collapsible stand, battery-operated ECG-monitor with optical and acoustical signal, a ECG-monitor with optical and acoustical signal, a battery-operated infusion pump, a Bird-respirator mark 8 with oxygen-blender, nebulizer and infant circuit with modification for PEEP as well as additional accessories. Ambulance-duty service is guaranteed by the German Red Cross (DRK) to facilitate transfer at any time, while skilled personal (physician, nurse) of the intensive care ward in on 24 hs call.

  2. Transport Modeling of Membrane Extraction of Chlorinated Hydrocarbon from Water for Ion Mobility Spectrometry

    SciTech Connect

    Zhang, Wei; Du, Yongzhai; Feng, Zhili; Xu, Jun

    2010-01-01

    Membrane-extraction Ion Mobility Spectrometry (ME-IMS) is a feasible technique for the continuous monitoring of chlorinated hydrocarbons in water. This work studies theoretically the time-dependent characteristics of sampling and detection of trichloroethylene (TCE). The sampling is configured so that aqueous contaminants permeate through a hollow polydimethylsiloxane (PDMS) membrane and are carried away by a transport gas flowing through the membrane tube into IMS analyzer. The theoretical study is based on a two-dimensional transient fluid flow and mass transport model. The model describes the TCE mixing in the water, permeation through the membrane layer, and convective diffusion in the air flow inside membrane tube. The effect of various transport gas flow rates on temporal profiles of IMS signal intensity is investigated. The results show that fast time response and high transport yield can be achieved for ME-IMS by controlling the flow rate in the extraction membrane tube. These modeled time-response profiles are important for determining duty cycles of field-deployable sensors for monitoring chlorinated hydrocarbons in water.

  3. Hydrothermal Processes and Mobile Element Transport in Martian Impact Craters - Evidence from Terrestrial Analogue Craters

    NASA Technical Reports Server (NTRS)

    Newsom, H. E.; Nelson, M. J.; Shearer, C. K.; Dressler, B. L.

    2005-01-01

    Hydrothermal alteration and chemical transport involving impact craters probably occurred on Mars throughout its history. Our studies of alteration products and mobile element transport in ejecta blanket and drill core samples from impact craters show that these processes may have contributed to the surface composition of Mars. Recent work on the Chicxulub Yaxcopoil-1 drill core has provided important information on the relative mobility of many elements that may be relevant to Mars. The Chicxulub impact structure in the Yucatan Peninsula of Mexico and offshore in the Gulf of Mexico is one of the largest impact craters identified on the Earth, has a diameter of 180-200 km, and is associated with the mass extinctions at the K/T boundary. The Yax-1 hole was drilled in 2001 and 2002 on the Yaxcopoil hacienda near Merida on the Yucatan Peninsula. Yax-1 is located just outside of the transient cavity, which explains some of the unusual characteristics of the core stratigraphy. No typical impact melt sheet was encountered in the hole and most of the Yax-1 impactites are breccias. In particular, the impact melt and breccias are only 100 m thick which is surprising taking into account the considerably thicker breccia accumulations towards the center of the structure and farther outside the transient crater encountered by other drill holes.

  4. The effect of molecular mobility on electronic transport in carbon nanotube-polymer composites and networks

    SciTech Connect

    Shenogin, Sergei; Lee, Jonghoon; Voevodin, Andrey A.; Roy, Ajit K.

    2014-12-21

    A multiscale modeling approach to the prediction of electrical conductivity in carbon nanotube (CNT)–polymer composite materials is developed, which takes into account thermally activated molecular mobility of the matrix and the CNTs. On molecular level, a tight-binding density functional theory and non-equilibrium Green's function method are used to calculate the static electron transmission function in the contact between two metallic carbon nanotubes that corresponds to electron transport at 0 K. For higher temperatures, the statistical distribution of effective contact resistances is considered that originates from thermal fluctuations of intermolecular distances caused by molecular mobility of carbon nanotube and the polymer matrix. Based on this distribution and using effective medium theory, the temperature dependence of macroscopic electrical resistivity for CNT-polymer composites and CNT mats is calculated. The predicted data indicate that the electrical conductivity of the CNT-polymer composites increases linearly with temperature above 50 K, which is in a quantitative agreement with the experiments. Our model predicts a slight nonlinearity in temperature dependence of electric conductivity at low temperatures for percolated composites with small CNT loading. The model also explains the effect of glass transition and other molecular relaxation processes in the polymer matrix on the composite electrical conductivity. The developed multiscale approach integrates the atomistic charge transport mechanisms in percolated CNT-polymer composites with the macroscopic response and thus enables direct comparison of the prediction with the measurements of macroscopic material properties.

  5. The effect of molecular mobility on electronic transport in carbon nanotube-polymer composites and networks

    NASA Astrophysics Data System (ADS)

    Shenogin, Sergei; Lee, Jonghoon; Voevodin, Andrey A.; Roy, Ajit K.

    2014-12-01

    A multiscale modeling approach to the prediction of electrical conductivity in carbon nanotube (CNT)-polymer composite materials is developed, which takes into account thermally activated molecular mobility of the matrix and the CNTs. On molecular level, a tight-binding density functional theory and non-equilibrium Green's function method are used to calculate the static electron transmission function in the contact between two metallic carbon nanotubes that corresponds to electron transport at 0 K. For higher temperatures, the statistical distribution of effective contact resistances is considered that originates from thermal fluctuations of intermolecular distances caused by molecular mobility of carbon nanotube and the polymer matrix. Based on this distribution and using effective medium theory, the temperature dependence of macroscopic electrical resistivity for CNT-polymer composites and CNT mats is calculated. The predicted data indicate that the electrical conductivity of the CNT-polymer composites increases linearly with temperature above 50 K, which is in a quantitative agreement with the experiments. Our model predicts a slight nonlinearity in temperature dependence of electric conductivity at low temperatures for percolated composites with small CNT loading. The model also explains the effect of glass transition and other molecular relaxation processes in the polymer matrix on the composite electrical conductivity. The developed multiscale approach integrates the atomistic charge transport mechanisms in percolated CNT-polymer composites with the macroscopic response and thus enables direct comparison of the prediction with the measurements of macroscopic material properties.

  6. The extreme mobility of debris avalanches: A new model of transport mechanism

    NASA Astrophysics Data System (ADS)

    Perinotto, Hélène; Schneider, Jean-Luc; Bachèlery, Patrick; Le Bourdonnec, François-Xavier; Famin, Vincent; Michon, Laurent

    2015-12-01

    Large rockslide-debris avalanches, resulting from flank collapses that shape volcanoes and mountains on Earth and other object of the solar system, are rapid and dangerous gravity-driven granular flows that travel abnormal distances. During the last 50 years, numerous physical models have been put forward to explain their extreme mobility. The principal models are based on fluidization, lubrication, or dynamic disintegration. However, these processes remain poorly constrained. To identify precisely the transport mechanisms during debris avalanches, we examined morphometric (fractal dimension and circularity), grain size, and exoscopic characteristics of the various types of particles (clasts and matrix) from volcanic debris avalanche deposits of La Réunion Island (Indian Ocean). From these data we demonstrate for the first time that syn-transport dynamic disintegration continuously operates with the increasing runout distance from the source down to a grinding limit of 500 µm. Below this limit, the particle size reduction exclusively results from their attrition by frictional interactions. Consequently, the exceptional mobility of debris avalanches may be explained by the combined effect of elastic energy release during the dynamic disintegration of the larger clasts and frictional reduction within the matrix due to interactions between the finer particles.

  7. Impact of river regulation on potential sediment mobilization and transport in an Alpine catchment

    NASA Astrophysics Data System (ADS)

    Costa, Anna; Molnar, Peter; Lane, Stuart N.; Bakker, Maarten

    2015-04-01

    The upper Rhône basin (upstream of Lake Geneva) has been heavily affected by human activities during the last century. The most evident impacts are related to river regulation, specifically flow impoundement, flow abstraction and channelization. In the last century and mainly since 1960, several large dams have been built along the main tributaries of the Rhône River, resulting in the water storage of a volume equal to 20% of the total annual river flow. The dams are part of hydropower systems which abstract water from streams and transfer it through complex networks (intakes, tunnels and pumping stations) to the reservoirs. Hydropower production leads to regulated flow in the Rhône: mostly an increase of winter flows, a reduction of summer flows, and a decrease of flood peaks. The sediment supply into Lake Geneva has decreased following dam construction (Loizeau & Dominik, 2000) due to the storage of sediment in upstream reservoirs, in rivers with reduced sediment transport capacity due to flow abstraction, and due to the development of sediment mining. Our hypothesis is that streamflow regulation itself has dramatically impacted the sediment transport dynamics of the system. We investigate the impacts of flow regulation on the sediment transport regime, by analysing the effects on potential sediment transport capacity (bedload). By the use of different bedload transport formulae (Meyer-Peter Müller, Wilcock and Crowe), the potential sediment transport capacity is computed at different cross sections within the basin. Potential sediment mobility occurs when the applied bed shear stress exceeds a critical value, τ>τc. The applied bed shear stress is computed as τ=ρghS, with water depth (h) measured from rating curves. We obtain an estimate of the energy slope (S) from the analysis of the river cross section, assuming uniform flow. The critical value of bed shear stress τc is computed using empirical formulae as a function of the grain diameter (ds). To

  8. LONG-TERM COLLOID MOBILIZATION AND COLLOID-FACILITATED TRANSPORT OF RADIONUCLIDES IN A SEMI-ARID VADOSE ZONE

    SciTech Connect

    Markus Flury; James B. Harsh; Fred Zhang; Glendon W. Gee; Earl D. Mattson; Peter C. L

    2012-08-01

    The main purpose of this project was to improve the fundamental mechanistic understanding and quantification of long-term colloid mobilization and colloid-facilitated transport of radionuclides in the vadose zone, with special emphasis on the semi-arid Hanford site. While we focused some of the experiments on hydrogeological and geochemical conditions of the Hanford site, many of our results apply to colloid and colloid-facilitated transport in general. Specific objectives were (1) to determine the mechanisms of colloid mobilization and colloid-facilitated radionuclide transport in undisturbed Hanford sediments under unsaturated flow, (2) to quantify in situ colloid mobilization and colloid-facilitated radionuclidetransport from Hanford sediments under field conditions, and (3) to develop a field-scale conceptual and numerical model for colloid mobilization and transport at the Hanford vadose zone, and use that model to predict long-term colloid and colloid- facilitated radionuclide transport. To achieve these goals and objectives, we have used a combination of experimental, theoretical, and numerical methods at different spatial scales, ranging from microscopic investigationsof single particle attachment and detachment to larger-scale field experiments using outdoor lysimeters at the Hanford site. Microscopic and single particle investigations provided fundamental insight into mechanisms of colloid interactions with the air-water interface. We could show that a moving air water interface (such as a moving water front during infiltration and drainage) is very effective in removing and mobilizing particles from a stationary surface. We further demonstrated that it is particularly the advancing air-water interface which is mainly responsible for colloid mobilization. Forces acting on the colloids calculated from theory corroborated our experimental results, and confirm that the detachment forces (surface tension forces) during the advancing air-water interface

  9. A Car Transportation System in Cooperation by Multiple Mobile Robots for Each Wheel: iCART II

    NASA Astrophysics Data System (ADS)

    Kashiwazaki, Koshi; Yonezawa, Naoaki; Kosuge, Kazuhiro; Sugahara, Yusuke; Hirata, Yasuhisa; Endo, Mitsuru; Kanbayashi, Takashi; Shinozuka, Hiroyuki; Suzuki, Koki; Ono, Yuki

    The authors proposed a car transportation system, iCART (intelligent Cooperative Autonomous Robot Transporters), for automation of mechanical parking systems by two mobile robots. However, it was difficult to downsize the mobile robot because the length of it requires at least the wheelbase of a car. This paper proposes a new car transportation system, iCART II (iCART - type II), based on “a-robot-for-a-wheel” concept. A prototype system, MRWheel (a Mobile Robot for a Wheel), is designed and downsized less than half the conventional robot. First, a method for lifting up a wheel by MRWheel is described. In general, it is very difficult for mobile robots such as MRWheel to move to desired positions without motion errors caused by slipping, etc. Therefore, we propose a follower's motion error estimation algorithm based on the internal force applied to each follower by extending a conventional leader-follower type decentralized control algorithm for cooperative object transportation. The proposed algorithm enables followers to estimate their motion errors and enables the robots to transport a car to a desired position. In addition, we analyze and prove the stability and convergence of the resultant system with the proposed algorithm. In order to extract only the internal force from the force applied to each robot, we also propose a model-based external force compensation method. Finally, proposed methods are applied to the car transportation system, the experimental results confirm their validity.

  10. Controls on the Mobilization and Transport of Hfse in Ore-Forming Magmatic-Hydrothermal Systems

    NASA Astrophysics Data System (ADS)

    Sanchez-Valle, C.; Louvel, M.

    2015-12-01

    The genesis of economical rare metals (Zr, Nb, REE) ore deposits in largegranitic complexes (e.g., Strange Lake and Thor Lake Nechalacho deposit, Canada; Galineiro complex, Spain) is related to the intrusion of alkaline halogen-rich magmatic bodies. Although the role of exolved magmatic fluids in the mobilization and transport of HFSE is widely recognized, the physico-chemical conditions and atomic-scale mechanisms that control the formation of the ore deposits remain poorly understood. We present new experimental constraints on behavior of HFSE during the exsolution of aqueous fluids from peralkaline granitic magmas at crustal conditions. In situ partitioning and speciation studies of Zr in the haplogranite-(F)-H2O systems using synchrotron X-ray spectroscopies provide evidence for large controls of fluid chemistry and temperature on the mobilization and transport of HFSE in crustal settings. At shallow crustal pressure conditions (> 800 °C and 0.3 GPa), Zr preferentially partitions into the exolved aqueous fluid in the presence of fluorine (Df/mZr = 1.40 ± 0.10) as previously reported for Nb in F- (and Cl-) bearing metaluminous granitic systems at similar conditions. The reverse partitioning of HFSE (Zr and Nb) into the aqueous phase at temperature above 800 °C contrast with the behavior observed at lower temperatures, where the Df/mZr remain lower than 1 at all pressures. The enrichment of the aqueous phase in HFSE (Zr, Nb) in the earlier stages of the magmatic evolution is likely related to the enhanced peralkalinity of low pressure (< 0.4 GPa), F-bearing aqueous fluid coexisting with granitic melts as temperature increases. This particular fluid chemistry provides the favorable conditions for the mobilization of HFSE via the formation of HFSE-O-Si/Na clusters in the fluid as shown by the in situ Zr speciation data. Our results show that the exsolution of highly alkaline early magmatic fluid at pressures below 0.4 GPa has the potential to extract HFSE from F

  11. Approaching disorder-free transport in high-mobility conjugated polymers.

    PubMed

    Venkateshvaran, Deepak; Nikolka, Mark; Sadhanala, Aditya; Lemaur, Vincent; Zelazny, Mateusz; Kepa, Michal; Hurhangee, Michael; Kronemeijer, Auke Jisk; Pecunia, Vincenzo; Nasrallah, Iyad; Romanov, Igor; Broch, Katharina; McCulloch, Iain; Emin, David; Olivier, Yoann; Cornil, Jerome; Beljonne, David; Sirringhaus, Henning

    2014-11-20

    Conjugated polymers enable the production of flexible semiconductor devices that can be processed from solution at low temperatures. Over the past 25 years, device performance has improved greatly as a wide variety of molecular structures have been studied. However, one major limitation has not been overcome; transport properties in polymer films are still limited by pervasive conformational and energetic disorder. This not only limits the rational design of materials with higher performance, but also prevents the study of physical phenomena associated with an extended π-electron delocalization along the polymer backbone. Here we report a comparative transport study of several high-mobility conjugated polymers by field-effect-modulated Seebeck, transistor and sub-bandgap optical absorption measurements. We show that in several of these polymers, most notably in a recently reported, indacenodithiophene-based donor-acceptor copolymer with a near-amorphous microstructure, the charge transport properties approach intrinsic disorder-free limits at which all molecular sites are thermally accessible. Molecular dynamics simulations identify the origin of this long sought-after regime as a planar, torsion-free backbone conformation that is surprisingly resilient to side-chain disorder. Our results provide molecular-design guidelines for 'disorder-free' conjugated polymers.

  12. A new approach to calculate charge carrier transport mobility in organic molecular crystals from imaginary time path integral simulations

    SciTech Connect

    Song, Linze; Shi, Qiang

    2015-05-07

    We present a new non-perturbative method to calculate the charge carrier mobility using the imaginary time path integral approach, which is based on the Kubo formula for the conductivity, and a saddle point approximation to perform the analytic continuation. The new method is first tested using a benchmark calculation from the numerical exact hierarchical equations of motion method. Imaginary time path integral Monte Carlo simulations are then performed to explore the temperature dependence of charge carrier delocalization and mobility in organic molecular crystals (OMCs) within the Holstein and Holstein-Peierls models. The effects of nonlocal electron-phonon interaction on mobility in different charge transport regimes are also investigated.

  13. Mobilization

    DTIC Science & Technology

    1987-01-01

    istic and romantic emotionalism that typifies this genre. Longino, James C., et al. “A Study of World War Procurement and Industrial Mobilization...States. Harrisburg, PA: Military Service Publishing Co., 1941. CARL 355.22 J72b. Written in rough prose , this World War II era document explains the

  14. (Relative mobilities and transport mechanisms of trace elements during contact metamorphism of carbonate rocks). Progress report

    SciTech Connect

    1980-01-01

    The main objective of this study is to investigate the relative mobilities and transport mechanisms of major, minor, and trace elements during the contact metamorphism of carbonate rocks. The large contrasts in chemical potentials of SiO/sub 2/, Al/sub 2/O/sub 3/, and CaO across a granitic pluton-limestone contact may induce metasomatism. In addition, rare earth and transition metal elements may act as tracers, and their redistribution during metamorphism may record convective cooling processes. The results of this study may have an application toward the problem of radioactive waste disposal and the degree to which radioactive nuclides may be expected to migrate during geologically significant periods of time.

  15. Global charcoal mobilization from soils via dissolution and riverine transport to the oceans.

    PubMed

    Jaffé, Rudolf; Ding, Yan; Niggemann, Jutta; Vähätalo, Anssi V; Stubbins, Aron; Spencer, Robert G M; Campbell, John; Dittmar, Thorsten

    2013-04-19

    Global biomass burning generates 40 million to 250 million tons of charcoal every year, part of which is preserved for millennia in soils and sediments. We have quantified dissolution products of charcoal in a wide range of rivers worldwide and show that globally, a major portion of the annual charcoal production is lost from soils via dissolution and subsequent transport to the ocean. The global flux of soluble charcoal accounts to 26.5 ± 1.8 million tons per year, which is ~10% of the global riverine flux of dissolved organic carbon (DOC). We suggest that the mobilization of charcoal and DOC out of soils is mechanistically coupled. This study closes a major gap in the global charcoal budget and provides critical information in the context of geoengineering.

  16. Colloids in groundwater: Their mobilization, subsurface transport, and sorption affinity for toxic chemicals

    SciTech Connect

    Not Available

    1991-01-01

    During the initial project period, we have pursued several activities with the overall goal of characterizing the roles of colloid in groundwater. First, we have collected soil cores from a site where we have previously found large quantities of kaolinite colloids in the groundwater. We have intensely investigated these cores to test our hypothesis that the colloids have been mobilized as a result of iron oxide dissolution. Next, we have constructed a soil core system in our laboratory with which we are attempting to mimic the factors that we think are governing colloid transport in the subsurface. Finally, we have pursued the issue of how well organic chemicals bind to the kinds of colloids that we are seeing at field sites. Together, with our knowledge of colloid mobility, we anticipate that this sorption data will enable us to predict the influence of groundwater colloids on contaminant fates in the subsurface. Our progress in each of these activities is described in this report. 7 refs., 12 figs.

  17. Excellent spin transport in spin valves based on the conjugated polymer with high carrier mobility

    PubMed Central

    Li, Feng; Li, Tian; Chen, Feng; Zhang, Fapei

    2015-01-01

    Organic semiconductors (OSCs) are characteristic of long spin-relaxation lifetime due to weak spin-orbit interaction and hyperfine interaction. However, short spin diffusion length and weak magnetoresistance (MR) effect at room temperature (RT) was commonly found on spin valves (SVs) using an organic spacer, which should be correlated with low carrier mobility of the OSCs. Here, N-type semiconducting polymer P(NDI2OD-T2) with high carrier mobility is employed as the spacer in the SV devices. Exceedingly high MR ratio of 90.0% at 4.2 K and of 6.8% at RT are achieved, respectively, via improving the interface structure between the polymer interlayer and top cobalt electrode as well as optimal annealing of manganite bottom electrode. Furthermore, we observe spin dependent transport through the polymeric interlayer and a large spin diffusion length with a weak temperature dependence. The results indicate that this polymer material can be used as a good medium for spintronic devices. PMID:25797862

  18. Contaminant transport in dual-porosity media with dissolved organic matter and bacteria present as mobile colloids.

    PubMed

    Kim, Song-Bae; Corapcioglu, M Yavuz

    2002-12-01

    In riverbank filtration, contaminant transport is affected by colloidal particles such as dissolved organic matter (DOM) and bacterial particles. In addition, the subsurface heterogeneity influences the behavior of contaminant transport in riverbank filtration. A mathematical model is developed to describe the contaminant transport in dual-porosity media in the presence of DOM and bacteria as mobile colloids. In the model development, a porous medium is divided into the mobile and immobile regions to consider the presence of ineffective micropores in physically heterogeneous riverbanks. We assume that the contaminant transport in the mobile region is controlled by the advection and dispersion while the contaminant transport in the immobile region occurs due to the molecular diffusion. The contaminant transfer between the mobile and immobile regions takes place by diffusive mass transfer. The mobile region is conceptualized as a four-phase system: two mobile colloidal phases, an aqueous phase, and a solid matrix. The complete set of governing equations is solved numerically with a fully implicit finite difference method. The model results show that in riverbank filtration, the contaminant can migrate further than expected due to the presence of DOM and bacteria. In addition, the contaminant mobility increases further in the presence of the immobile region in aquifers. A sensitivity analysis shows that in dual-porosity media, earlier breakthrough of the contaminant takes place as the volumetric fraction of the mobile region decreases. It is also demonstrated that as the contaminant mass transfer rate coefficient between the mobile and immobile regions increases, the contaminant concentration gradient between the two regions reverses at earlier pore volumes. The contaminant mass transfer coefficient between the mobile and immobile regions mainly controls the tailing effect of the contaminant breakthrough. The contaminant breakthrough curves are sensitive to changes in

  19. Coupled effects of solution chemistry and hydrodynamics on the mobility and transport of quantum dot nanomaterials in the vadose zone

    NASA Astrophysics Data System (ADS)

    Uyusur, Burcu; Darnault, Christophe J. G.; Snee, Preston T.; Kokën, Emre; Jacobson, Astrid R.; Wells, Robert R.

    2010-11-01

    To investigate the coupled effects of solution chemistry and hydrodynamics on the mobility of quantum dot (QD) nanoparticles in the vadose zone, laboratory scale transport experiments involving single and/or sequential infiltrations of QDs in unsaturated and saturated porous media, and computations of total interaction and capillary potential energies were performed. As ionic strength increased, QD retention in the unsaturated porous media increased; however, this retention was significantly suppressed in the presence of a non-ionic surfactant in the infiltration suspensions as indicated by surfactant enhanced transport of QDs. In the vadose zone, the non-ionic surfactant limited the formation of QD aggregates, enhanced QD mobility and transport, and lowered the solution surface tension, which resulted in a decrease in capillary forces that not only led to a reduction in the removal of QDs, but also impacted the vadose zone flow processes. When chemical transport conditions were favorable (ionic strength of 5 × 10 -4 M and 5 × 10 -3 M, or ionic strengths of 5 × 10 -2 M and 0.5 M with surfactant), the dominating phenomena controlling the mobility and transport of QDs in the vadose zone were meso-scale processes, where infiltration by preferential flow results in the rapid transport of QDs. When chemical transport conditions were unfavorable (ionic strength of 5 × 10 -2 M and 0.5 M) the dominating phenomena controlling the mobility and transport of QDs in the vadose zone were pore-scale processes governed by gas-water interfaces (GWI) that impact the mobility of QDs. The addition of surfactant enhanced the transport of QDs both in favorable and unfavorable chemical transport conditions. The mobility and retention of QDs was controlled by interaction and capillary forces, with the latter being the most influential. GWI were found to be the dominant mechanism and site for QD removal compared with solid-water interfaces (SWI) and pore straining. Additionally

  20. Assessment of Historic Trend in Mobility and Energy Use in India Transportation Sector Using Bottom-up Approach

    SciTech Connect

    Zhou, Nan; McNeil, Michael A.

    2009-05-01

    Transportation mobility in India has increased significantly in the past decades. From 1970 to 2000, motorized mobility (passenger-km) has risen by 888%, compared with an 88% population growth (Singh,2006). This contributed to many energy and environmental issues, and an energy strategy incorporates efficiency improvement and other measures needs to be designed. Unfortunately, existing energy data do not provide information on driving forces behind energy use and sometime show large inconsistencies. Many previous studies address only a single transportation mode such as passenger road travel; did not include comprehensive data collection or analysis has yet been done, or lack detail on energy demand by each mode and fuel mix. The current study will fill a considerable gap in current efforts, develop a data base on all transport modes including passenger air and water, and freight in order to facilitate the development of energy scenarios and assess significance of technology potential in a global climate change model. An extensive literature review and data collection has been done to establish the database with breakdown of mobility, intensity, distance, and fuel mix of all transportation modes. Energy consumption was estimated and compared with aggregated transport consumption reported in IEA India transportation energy data. Different scenarios were estimated based on different assumptions on freight road mobility. Based on the bottom-up analysis, we estimated that the energy consumption from 1990 to 2000 increased at an annual growth rate of 7% for the mid-range road freight growth case and 12% for the high road freight growth case corresponding to the scenarios in mobility, while the IEA data only shows a 1.7% growth rate in those years.

  1. Coupled effects of solution chemistry and hydrodynamics on the mobility and transport of quantum dot nanomaterials in the Vadose Zone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To investigate the coupled effects of solution chemistry and vadose zone processes on the mobility of quantum dot (QD) nanoparticles, laboratory scale transport experiments were performed. The complex coupled effects of ionic strength, size of QD aggregates, surface tension, contact angle, infiltrat...

  2. 41 CFR 302-10.202 - Am I entitled to any other allowances when I transport my mobile home by POV?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 4 2013-07-01 2012-07-01 true Am I entitled to any other allowances when I transport my mobile home by POV? 302-10.202 Section 302-10.202 Public Contracts... Computation of Allowances § 302-10.202 Am I entitled to any other allowances when I transport my mobile...

  3. 41 CFR 302-10.201 - What is the mileage allowance when you transport a mobile home overland by a POV?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false What is the mileage allowance when you transport a mobile home overland by a POV? 302-10.201 Section 302-10.201 Public Contracts... Computation of Allowances § 302-10.201 What is the mileage allowance when you transport a mobile home...

  4. 41 CFR 302-10.202 - Am I entitled to any other allowances when I transport my mobile home by POV?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false Am I entitled to any other allowances when I transport my mobile home by POV? 302-10.202 Section 302-10.202 Public Contracts... Computation of Allowances § 302-10.202 Am I entitled to any other allowances when I transport my mobile...

  5. A two-tiered approach to reactive transport: Application to Sr mobility under variable pH

    SciTech Connect

    Toran, L.; Bryant, S.; Wheeler, M.F.; Saunders, J.

    1998-05-01

    One benefit of a coupled geochemistry/transport approach is that interactions between chemical constituents that can change the mobility of species (such as pH) can be treated explicitly, rather than lumping all of the geochemistry into a single term (i.e., the retardation factor). A two-tiered approach to modeling coupled geochemistry/transport is presented here, which allows a comparison of the results of different methods as well as better efficiency in modeling time. The codes ParSSim, a coupled transport code for supercomputers, and PHREEQC, an advective geochemistry code, were used to model Sr mobility under varying pH. The problem was based on liquid low level radioactive waste that was disposed at Oak Ridge National Laboratory (Oak Ridge, Tennessee) in a highly alkaline solution to try to enhance precipitation and sorption. Interactions with carbonate rock and ground water lowered the pH and led to mobilization of radionuclides such as {sup 90}Sr. Simulation of contaminant migration in this mixing environment requires a coupled geochemistry and transport model. The interplay between propagation of a pH front (which was retarded) and propagation of the Sr front leads to a fast-moving pulse of Sr as well as a strongly retarded front of Sr. This behavior could not have been predicted by a geochemistry or a transport code alone.

  6. Symmetric caging formation for convex polygonal object transportation by multiple mobile robots based on fuzzy sliding mode control.

    PubMed

    Dai, Yanyan; Kim, YoonGu; Wee, SungGil; Lee, DongHa; Lee, SukGyu

    2016-01-01

    In this paper, the problem of object caging and transporting is considered for multiple mobile robots. With the consideration of minimizing the number of robots and decreasing the rotation of the object, the proper points are calculated and assigned to the multiple mobile robots to allow them to form a symmetric caging formation. The caging formation guarantees that all of the Euclidean distances between any two adjacent robots are smaller than the minimal width of the polygonal object so that the object cannot escape. In order to avoid collision among robots, the parameter of the robots radius is utilized to design the caging formation, and the A⁎ algorithm is used so that mobile robots can move to the proper points. In order to avoid obstacles, the robots and the object are regarded as a rigid body to apply artificial potential field method. The fuzzy sliding mode control method is applied for tracking control of the nonholonomic mobile robots. Finally, the simulation and experimental results show that multiple mobile robots are able to cage and transport the polygonal object to the goal position, avoiding obstacles.

  7. An investigation of the multicarrier transport properties of ?-doped InSb at high temperatures using a mobility spectrum technique

    NASA Astrophysics Data System (ADS)

    Panaev, I. A.; Studenikin, S. A.; Tkachenko, V. A.; Tkachenko, O. A.; Heremans, J. P.; Partin, D. L.; Morelli, D. T.; Thrush, C. M.

    1996-12-01

    Transport properties of Si-0268-1242/11/12/016/img12-doped InSb grown by molecular beam epitaxy are studied. The mobility spectrum (MS) analysis made over a wide temperature range reveals three species of carriers: those associated with the bulk of the film, and electrons in quantized subbands in the 0268-1242/11/12/016/img12-layer. At low temperatures the MS data are consistent with self-consistent calculations and measurements of the Shubnikov - de Haas oscillations. The far-infrared cyclotron resonance lineshapes are well described by the Drude approximation using the obtained values of subband mobilities, concentrations and effective masses.

  8. Density-dependent electron transport and precise modeling of GaN high electron mobility transistors

    SciTech Connect

    Bajaj, Sanyam Shoron, Omor F.; Park, Pil Sung; Krishnamoorthy, Sriram; Akyol, Fatih; Hung, Ting-Hsiang; Reza, Shahed; Chumbes, Eduardo M.; Khurgin, Jacob; Rajan, Siddharth

    2015-10-12

    We report on the direct measurement of two-dimensional sheet charge density dependence of electron transport in AlGaN/GaN high electron mobility transistors (HEMTs). Pulsed IV measurements established increasing electron velocities with decreasing sheet charge densities, resulting in saturation velocity of 1.9 × 10{sup 7 }cm/s at a low sheet charge density of 7.8 × 10{sup 11 }cm{sup −2}. An optical phonon emission-based electron velocity model for GaN is also presented. It accommodates stimulated longitudinal optical (LO) phonon emission which clamps the electron velocity with strong electron-phonon interaction and long LO phonon lifetime in GaN. A comparison with the measured density-dependent saturation velocity shows that it captures the dependence rather well. Finally, the experimental result is applied in TCAD-based device simulator to predict DC and small signal characteristics of a reported GaN HEMT. Good agreement between the simulated and reported experimental results validated the measurement presented in this report and established accurate modeling of GaN HEMTs.

  9. Complex quantum transport in a modulation doped strained Ge quantum well heterostructure with a high mobility 2D hole gas

    NASA Astrophysics Data System (ADS)

    Morrison, C.; Casteleiro, C.; Leadley, D. R.; Myronov, M.

    2016-09-01

    The complex quantum transport of a strained Ge quantum well (QW) modulation doped heterostructure with two types of mobile carriers has been observed. The two dimensional hole gas (2DHG) in the Ge QW exhibits an exceptionally high mobility of 780 000 cm2/Vs at temperatures below 10 K. Through analysis of Shubnikov de-Haas oscillations in the magnetoresistance of this 2DHG below 2 K, the hole effective mass is found to be 0.065 m0. Anomalous conductance peaks are observed at higher fields which deviate from standard Shubnikov de-Haas and quantum Hall effect behaviour due to conduction via multiple carrier types. Despite this complex behaviour, analysis using a transport model with two conductive channels explains this behaviour and allows key physical parameters such as the carrier effective mass, transport, and quantum lifetimes and conductivity of the electrically active layers to be extracted. This finding is important for electronic device applications, since inclusion of highly doped interlayers which are electrically active, for enhancement of, for example, room temperature carrier mobility, does not prevent analysis of quantum transport in a QW.

  10. Wheeled mobility device transportation safety in fixed route and demand-responsive public transit vehicles within the United States.

    PubMed

    Frost, Karen L; van Roosmalen, Linda; Bertocci, Gina; Cross, Douglas J

    2012-01-01

    An overview of the current status of wheelchair transportation safety in fixed route and demand-responsive, non-rail, public transportation vehicles within the US is presented. A description of each mode of transportation is provided, followed by a discussion of the primary issues affecting safety, accessibility, and usability. Technologies such as lifts, ramps, securement systems, and occupant restraint systems, along with regulations and voluntary industry standards have been implemented with the intent of improving safety and accessibility for individuals who travel while seated in their wheeled mobility device (e.g., wheelchair or scooter). However, across both fixed route and demand-responsive transit systems a myriad of factors such as nonuse and misuse of safety systems, oversized wheeled mobility devices, vehicle space constraints, and inadequate vehicle operator training may place wheeled mobility device (WhMD) users at risk of injury even under non-impact driving conditions. Since WhMD-related incidents also often occur during the boarding and alighting process, the frequency of these events, along with factors associated with these events are described for each transit mode. Recommendations for improving WhMD transportation are discussed given the current state of

  11. How to regulate energy levels and hole mobility of spiro-type hole transport materials in perovskite solar cells.

    PubMed

    Chi, Wei-Jie; Sun, Ping-Ping; Li, Ze-Sheng

    2016-10-21

    Methoxyaniline-based organic small molecules with three-dimensional structure have been proven as the most promising hole conductor for state-of-the-art perovskite devices. A fundamental understanding of the electronic properties and hole transport behavior of spiro-CPDT analogues, which is dependent on the number and position of the -OCH3 groups, is significant for their potential applications as hole transport materials of perovskite solar cells. Our results from density functional theory calculations indicate that meta-substitution is more beneficial to reduce the highest occupied molecular orbital (HOMO) levels of molecules compared with ortho- and para-substitution. Furthermore, the hole mobility can be improved by ortho-substitution or mixed ortho- and para-substitution. Most interestingly, it is found that the improvement in hole mobility is at the expense of raising the HOMO level of spiro-CPDT analogues. These results can be useful in the process of designing and synthesizing excellent hole transport materials with suitable HOMO levels and high hole mobility.

  12. Cancellations of (helicopter-transported) mobile medical team dispatches in the Netherlands

    PubMed Central

    Lubbers, Wouter D.; Christiaans, Herman M. T.; van Exter, Pieternel; Bet, Piet; Hugen, Paul J. C.; Innemee, Gerard; Schubert, Edo; de Lange-Klerk, Elly S. M.; Goslings, J. Carel; Jukema, Gerrolt N.

    2010-01-01

    Background The trauma centre of the Trauma Center Region North-West Netherlands (TRNWN) has consensus criteria for Mobile Medical Team (MMT) scene dispatch. The MMT can be dispatched by the EMS-dispatch centre or by the on-scene ambulance crew and is transported by helicopter or ground transport. Although much attention has been paid to improve the dispatch criteria, the MMT is often cancelled after being dispatched. The aim of this study was to assess the cancellation rate and the noncompliant dispatches of our MMT and to identify factors associated with this form of primary overtriage. Methods By retrospective analysis of all MMT dispatches in the period from 1 July 2006 till 31 December 2006 using chart review, we conducted a consecutive case review of 605 dispatches. Four hundred and sixty seven of these were included for our study, collecting data related to prehospital triage, patient’s condition on-scene and hospital course. Results Average age was 35.9 years; the majority of the patients were male (65.3%). Four hundred and thirty patients were victims of trauma, sustaining injuries in most cases from blunt trauma (89.3%). After being dispatched, the MMT was cancelled 203 times (43.5%). Statistically significant differences between assists and cancellations were found for overall mortality, mean RTS, GCS and ISS, mean hospitalization, length and amount of ICU admissions (p < 0.001). All dispatches were evaluated by using the MMT-dispatch criteria and mission appropriateness criteria. Almost 26% of all dispatches were neither appropriate, nor met the dispatch criteria. Fourteen missions were appropriate, but did not meet the dispatch criteria. The remaining 318 dispatches had met the dispatch criteria, of which 135 (30.3%) were also appropriate. The calculated additional costs of the cancelled dispatches summed up to a total of € 34,448, amounting to 2.2% of the total MMT costs during the study period. Conclusion In our trauma system, the MMT

  13. Transnational Sea-Ice Transport in a Warmer, More Mobile Arctic

    NASA Astrophysics Data System (ADS)

    Newton, R.; Tremblay, B.; Pfirman, S. L.; DeRepentigny, P.

    2015-12-01

    As the Arctic sea ice thins, summer ice continues to shrink in its area, and multi-year ice becomes rarer, winter ice is not disappearing from the Arctic Basin. Rather, it is ever more dominated by first year ice. And each summer, as the total coverage withdraws, the first year ice is able travel faster and farther, carrying any ice-rafted material with it. Micro-organisms, sediments, pollutants and river runoff all move across the Arctic each summer and are deposited hundreds of kilometers from their origins. Analyzing Arctic sea ice drift patterns in the context of the exclusive economic zones (EEZs) of the Arctic nations raises concerns about the changing fate of "alien" ice which forms within one country's EEZ, then drifts and melts in another country's EEZ. We have developed a new data set from satellite-based ice-drift data that allows us to track groups of ice "pixels" forward from their origin to their destination, or backwards from their melting location to their point of formation. The software has been integrated with model output to extend the tracking of sea ice to include climate projections. Results indicate, for example, that Russian sea ice dominates "imports" to the EEZ of Norway, as expected, but with increasing ice mobility it is also is exported into the EEZs of other countries, including Canada and the United States. Regions of potential conflict are identified, including several national borders with extensive and/or changing transboundary sea ice transport. These data are a starting point for discussion of transborder questions raised by "alien" ice and the material it may import from one nation's EEZ to another's.

  14. Hopping charge transport in molecularly doped polymers: Polymer matrix dependence of the hole drift mobility

    NASA Astrophysics Data System (ADS)

    Kanemitsu, Yoshihiko

    1992-03-01

    Effects of the polymer matrix on the drift mobility of holes in polymers doped with 2-(p-dipropylaminophenyl)-4-(p-dimethylaminophenyl)-5-(o-chlorophenyl)-1, 3-oxazole were studied by means of time-of-flight photoconductivity measurements. The drift mobility at zero field, the activation energy for hopping, and the electric field dependence of the mobility strongly depend on the polymer composition. These polymer matrix dependence of the drift mobility are largely related to energetic disorder of hopping sites in binary solid solution.

  15. Mobile ER-to-Golgi but not post-Golgi membrane transport carriers disappear during the terminal myogenic differentiation.

    PubMed

    Nevalainen, Mika; Kaisto, Tuula; Metsikkö, Kalervo

    2010-10-01

    The organelles of the exocytic pathway undergo a profound reorganization during the myogenic differentiation. Here, we have investigated the dynamics of the membrane trafficking at various stages of the differentiation process by using the green fluorescent protein-tagged, temperature-sensitive vesicular stomatitis virus G protein (tsG-GFP) as a marker. At the restrictive temperature of 39°C, the tsG-GFP located to the endoplasmic reticulum (ER) at each stage of differentiation. Mobile membrane containers moving from the ER to the Golgi elements were seen in myoblasts and myotubes upon shifting the temperature to 20°C. In adult myofibers, in contrast, such containers were not seen although the tsG-GFP rapidly shifted from the ER to the Golgi elements. The mobility of tsG-GFP in the myofiber ER was restricted, suggesting localization in an ER sub-compartment. Contrasting with the ER-to-Golgi trafficking, transport from the Golgi elements to the plasma membrane involved mobile transport containers in all differentiation stages. These findings indicate that ER-to-Golgi trafficking in adult skeletal myofibers does not involve long-distance moving membrane carriers as occurs in other mammalian cell types.

  16. Interhospital Transport System for Critically Ill Patients: Mobile Extracorporeal Membrane Oxygenation without a Ventilator

    PubMed Central

    Yeo, Hye Ju; Cho, Woo Hyun; Park, Jong Myung; Kim, Dohyung

    2017-01-01

    Background Extracorporeal membrane oxygenation (ECMO) has been successfully used as a method for the interhospital transportation of critically ill patients. In South Korea, a well-established ECMO interhospital transport system is lacking due to limited resources. We developed a simplified ECMO transport system without mechanical ventilation for use by public emergency medical services. Methods Eighteen patients utilized our ECMO transport system from December 2011 to September 2015. We retrospectively analyzed the indications for ECMO, the patient status during transport, and the patient outcomes. Results All transport was conducted on the ground by ambulance. The distances covered ranged from 26 to 408 km (mean, 65.9±88.1 km) and the average transport time was 56.1±57.3 minutes (range, 30 to 280 minutes). All patients were transported without adverse events. After transport, 4 patients (22.2%) underwent lung transplantation because of interstitial lung disease. Eight patients who had severe acute respiratory distress syndrome showed recovery of heart and lung function after ECMO therapy. A total of 13 patients (70.6%) were successfully taken off ECMO, and 11 patients (61.1%) survived. Conclusion Our ECMO transport system without mechanical ventilation can be considered a safe and useful method for interhospital transport and could be a good alternative option for ECMO transport in Korean hospitals with limited resources. PMID:28180097

  17. Decoupling Charge Transport and Electroluminescence in a High Mobility Polymer Semiconductor.

    PubMed

    Harkin, David J; Broch, Katharina; Schreck, Maximilian; Ceymann, Harald; Stoy, Andreas; Yong, Chaw-Keong; Nikolka, Mark; McCulloch, Iain; Stingelin, Natalie; Lambert, Christoph; Sirringhaus, Henning

    2016-08-01

    Fluorescence enhancement of a high-mobility polymer semiconductor is achieved via energy transfer to a higher fluorescence quantum yield squaraine dye molecule on 50 ps timescales. In organic light-emitting diodes, an order of magnitude enhancement of the external quantum efficiency is observed without reduction in the charge-carrier mobility resulting in radiances of up to 5 W str(-1) m(-2) at 800 nm.

  18. Devices using ballistic transport of two dimensional electron gas in delta doped gallium arsenide high electron mobility transistor structures

    NASA Astrophysics Data System (ADS)

    Kang, Sungmu

    In this thesis, devices using the ballistic transport of two dimensional electron gas (2DEG) in GaAs High Electron Mobility Transistor(HEMT) structure is fabricated and their dc and ac properties are characterized. This study gives insight on operation and applications of modern submicron devices with ever reduced gate length comparable to electron mean free path. The ballistic transport is achieved using both temporal and spatial limits in this thesis. In temporal limit, when frequency is higher than the scattering frequency (1/(2pitau)), ballistic transport can be achieved. At room temperature, generally the scattering frequency is around 500 GHz but at cryogenic temperature (≤4K) with high mobility GaAs HEMT structure, the frequency is much lower than 2 GHz. On this temporal ballistic transport regime, effect of contact impedance and different dc mobility on device operation is characterized with the ungated 2DEG of HEMT structure. In this ballistic regime, impedance and responsivity of plasma wave detector are investigated using the gated 2DEG of HEMT at different ac boundary conditions. Plasma wave is generated at asymmetric ac boundary conditions of HEMTs, where source is short to ground and drain is open while rf power is applied to gate. The wave velocity can be tuned by gate bias voltage and induced drain to source voltage(Vds ) shows the resonant peak at odd number of fundamental frequency. Quantitative power coupling to plasma wave detector leads to experimental characterization of resonant response of plasma wave detector as a function of frequency. Because plasma wave resonance is not limited by transit time, the physics learned in this study can be directly converted to room temperature terahertz detection by simply reducing gate length(Lgate) to submicron for the terahertz application such as non destructive test, bio medical analysis, homeland security, defense and space. In same HEMT structure, the dc and rf characterization on device is also

  19. 41 CFR 302-10.300 - May I receive an advance of funds when a commercial carrier transports the mobile home?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false May I receive an advance of funds when a commercial carrier transports the mobile home? 302-10.300 Section 302-10.300 Public... Advance of Funds § 302-10.300 May I receive an advance of funds when a commercial carrier transports...

  20. 41 CFR 302-10.6 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false Are the allowances for transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses, for me and my immediate family member(s)? 302-10.6 Section 302-10.6 Public Contracts and...

  1. 41 CFR 302-10.401 - Are the allowances for transporting a mobile home in addition to the allowances for per diem...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false Are the allowances for transporting a mobile home in addition to the allowances for per diem, mileage, and transportation expenses, for an employee and immediate family member(s)? 302-10.401 Section 302-10.401 Public Contracts...

  2. School Travel Planning: Mobilizing School and Community Resources to Encourage Active School Transportation

    ERIC Educational Resources Information Center

    Buliung, Ron; Faulkner, Guy; Beesley, Theresa; Kennedy, Jacky

    2011-01-01

    Background: Active school transport (AST), school travel using an active mode like walking, may be important to children's overall physical activity. A "school travel plan" (STP) documents a school's transport characteristics and provides an action plan to address school and neighborhood barriers to AST. Methods: We conducted a pilot STP…

  3. Mobility transition from ballistic to diffusive transport in non-Hermitian lattices.

    PubMed

    Eichelkraut, T; Heilmann, R; Weimann, S; Stützer, S; Dreisow, F; Christodoulides, D N; Nolte, S; Szameit, A

    2013-01-01

    Within all physical disciplines, it is accepted that wave transport is predetermined by the existence of disorder. In this vein, it is known that ballistic transport is possible only when a structure is ordered, and that disorder is crucial for diffusion or (Anderson-)localization to occur. As this commonly accepted picture is based on the very foundations of quantum mechanics where Hermiticity of the Hamiltonian is naturally assumed, the question arises whether these concepts of transport hold true within the more general context of non-Hermitian systems. Here we demonstrate theoretically and experimentally that in ordered time-independent -symmetric systems, which are symmetric under space-time reflection, wave transport can undergo a sudden change from ballistic to diffusive after a specific point in time. This transition as well as the diffusive transport in general is impossible in Hermitian systems in the absence of disorder. In contrast, we find that this transition depends only on the degree of dissipation.

  4. Mobility and fluxes of major, minor and trace metals during basalt weathering and groundwater transport at Mt. Etna volcano (Sicily)

    SciTech Connect

    Aiuppa, A.; Allard, P.; D'Alessandro, W.; Michel, A.; Parello, F.; Treuil, M.; Valenza, M.

    2000-06-01

    The concentrations and fluxes of major, minor and trace metals were determined in 53 samples of groundwaters from around Mt. Etna, in order to evaluate the conditions and extent of alkali basalt weathering by waters enriched in magma-derived CO{sub 2} and the contribution of aqueous transport to the overall metal discharge of the volcano. The authors show that gaseous input of magmatic volatile metals into the Etnean aquifer is small or negligible, being limited by cooling of the rising fluids. Basalt leaching by weakly acidic, CO{sub 2}-charged water is the overwhelming source of metals and appears to be more extensive in two sectors of the S-SW (Paterno) and E (Zafferana) volcano flanks, where out flowing groundwaters are the richest in metals and bicarbonate of magmatic origin. Thermodynamic modeling of the results allows evaluation of the relative mobility and chemical speciation of various elements during their partitioning between solid and liquid phases through the weathering process. At Mt. Etna, poorly mobile elements (Al, Th, Fe) are preferentially retained in the solid residue of weathering, while alkalis, alkaline earth and oxo-anion-forming elements (As, Se, Sb, Mo) are more mobile and released to the aqueous system. Transition metals display an intermediate behavior and are strongly dependent on either the redox conditions (Mn, Cr, V) or solid surface-related processes (V, Zn, Cu).

  5. Disordered RuO2 exhibits two dimensional, low-mobility transport and a metal–insulator transition

    PubMed Central

    Osofsky, M. S.; Krowne, C. M.; Charipar, K. M.; Bussmann, K.; Chervin, C. N.; Pala, I. R.; Rolison, D. R.

    2016-01-01

    The discovery of low-dimensional metallic systems such as high-mobility metal oxide field-effect transistors, the cuprate superconductors, and conducting oxide interfaces (e.g., LaAlO3/SrTiO3) has stimulated research into the nature of electronic transport in two-dimensional systems given that the seminal theory for transport in disordered metals predicts that the metallic state cannot exist in two dimensions (2D). In this report, we demonstrate the existence of a metal–insulator transition (MIT) in highly disordered RuO2 nanoskins with carrier concentrations that are one-to-six orders of magnitude higher and with mobilities that are one-to-six orders of magnitude lower than those reported previously for 2D oxides. The presence of an MIT and the accompanying atypical electronic characteristics place this form of the oxide in a highly diffusive, strong disorder regime and establishes the existence of a metallic state in 2D that is analogous to the three-dimensional case. PMID:26915411

  6. Mobilization and transport of metal-rich colloidal particles from mine tailings into soil under transient chemical and physical conditions.

    PubMed

    Lu, Cong; Wu, Yaoguo; Hu, Sihai; Raza, Muhammad Ali; Fu, Yilin

    2016-04-01

    Exposed mine tailing wastes with considerable heavy metals can release hazardous colloidal particles into soil under transient chemical and physical conditions. Two-layered packed columns with tailings above and soils below were established to investigate mobilization and transport of colloidal particles from metal-rich mine tailings into soil under transient infiltration ionic strength (IS: 100, 20, 2 mM) and flow rate (FR: 20.7, 41, and 62.3 mm h(-1)), with Cu and Pb as representatives of the heavy metals. Results show that the tailing particles within the colloidal size (below 2 μm) were released from the columns. A step-decrease in infiltration IS and FR enhanced, whereas a step-increase in the IS and FR restrained the release of tailing particles from the column. The effects of step-changing FR were unexpected due to the small size of the released tailing particles (220-342 nm, being not sensitive to hydrodynamic shear force), the diffusion-controlled particle release process and the relatively compact pore structure. The tailing particles present in the solution with tested IS were found negatively charged and more stable than soil particles, which provides favorable conditions for tailing particles to be transported over a long distance in the soil. The mobilization and transport of Cu and Pb from the tailings into soil were mediated by the tailing particles. Therefore, the inherent toxic tailing particles could be considerably introduced into soil under certain conditions (IS reduction or FR decrease), which may result in serious environmental pollution.

  7. Colloids in groundwater: Their mobilization, subsurface transport, and sorption affinity for toxic chemicals

    SciTech Connect

    Gschwend, P.M.

    1992-07-10

    Our originally stated objectives included: (1) development of a quantitative source function for colloid mobilization to groundwater, and (2) assessment of the most important colloidal phases to which nonpolar compounds sorb. We have been pursuing a series of studies to elucidate the roles of colloidal phases in subsurface environments. Most notably, we have discovered the critical role of secondary cementitious phases like goethite. We developed a new procedure for measuring surface iron oxides'' which is a great improvement over earlier methodologies. Currently, we are developing a unifying model with which we can predict the mobilization of colloids to groundwater flowing through such porous media. Also, we have been able to show that groundwater samples contain colloidal phases in sufficient quantities and of suitable properties to enhance the mobile load of toxic compounds like polycyclic aromatic hydrocarbons. Finally, we have synthesized our varied field investigations from sites in Massachusetts, New Jersey, Delaware, Nevada, Connecticut, and New York to yield a protocol for other researchers interested in evaluating colloids in groundwater. These accomplishments are discussed in more detail below. Through these efforts, we have become increasingly convinced of the central role played by colloidal phases in numerous subsurface phenomena controlling contaminant fates.

  8. Transportation in an aging society: improving mobility and safety for older persons. Volume 1. Committee report and recommendations. Special report

    SciTech Connect

    Not Available

    1988-01-01

    In June 1986, the Transportation Research Board began a project to investigate the needs and problems of older Americans in relation to the U.S. roadway-transportation system. A committee of experts was appointed to review the design and operational features of the roadway system and to recommend steps to improve the mobility and safety of older users--drivers, passengers, pedestrians--who are an integral part of the system. The committees found that people over the age of 75 are involved in more fatal crashes than any other group except teenagers. Nevertheless they decided that 'age alone is a poor predictor of the performance of any individual.' Rather than restricting licenses at any given maximum age, the committee recommended that highway safety be improved by making adjustments to the design of highway features and that license screening tests be adapted to better identify people of all ages who have impairments that would affect driving. The committee also recommended improved specialized transportation for the frail elderly.

  9. Salinity mobilization and transport from rangelands: assessment, recommendations, and knowledge gaps

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of the salinity project is to improve the understanding of sources and transport mechanisms in rangeland catchments that deliver dissolved solids (salts) to streams within the Upper Colorado River Basin (UCRB) through a review of relevant literature on what is known about the impact of r...

  10. Simulation of Flow, Sediment Transport, and Sediment Mobility of the Lower Coeur d'Alene River, Idaho

    USGS Publications Warehouse

    Berenbrock, Charles; Tranmer, Andrew W.

    2008-01-01

    A one-dimensional sediment-transport model and a multi-dimensional hydraulic and bed shear stress model were developed to investigate the hydraulic, sediment transport, and sediment mobility characteristics of the lower Coeur d?Alene River in northern Idaho. This report documents the development and calibration of those models, as well as the results of model simulations. The one-dimensional sediment-transport model (HEC-6) was developed, calibrated, and used to simulate flow hydraulics and erosion, deposition, and transport of sediment in the lower Coeur d?Alene River. The HEC-6 modeled reach, comprised of 234 cross sections, extends from Enaville, Idaho, on the North Fork of the Coeur d?Alene River and near Pinehurst, Idaho, on the South Fork of the river to near Harrison, Idaho, on the main stem of the river. Bed-sediment samples collected by previous investigators and samples collected for this study in 2005 were used in the model. Sediment discharge curves from a previous study were updated using suspended-sediment samples collected at three sites since April 2000. The HEC-6 was calibrated using river discharge and water-surface elevations measured at five U.S. Geological Survey gaging stations. The calibrated HEC-6 model allowed simulation of management alternatives to assess erosion and deposition from proposed dredging of contaminated streambed sediments in the Dudley reach. Four management alternatives were simulated with HEC-6. Before the start of simulation for these alternatives, seven cross sections in the reach near Dudley, Idaho, were deepened 20 feet?removing about 296,000 cubic yards of sediments?to simulate dredging. Management alternative 1 simulated stage-discharge conditions from 2000, and alternative 2 simulated conditions from 1997. Results from alternatives 1 and 2 indicated that about 6,500 and 12,300 cubic yards, respectively, were deposited in the dredged reach. These figures represent 2 and 4 percent, respectively, of the total volume of

  11. Linking aquifer spatial properties and non-Fickian transport in mobile-immobile like alluvial settings

    USGS Publications Warehouse

    Zhang, Yong; Green, Christopher T.; Baeumer, Boris

    2014-01-01

    Time-nonlocal transport models can describe non-Fickian diffusion observed in geological media, but the physical meaning of parameters can be ambiguous, and most applications are limited to curve-fitting. This study explores methods for predicting the parameters of a temporally tempered Lévy motion (TTLM) model for transient sub-diffusion in mobile–immobile like alluvial settings represented by high-resolution hydrofacies models. The TTLM model is a concise multi-rate mass transfer (MRMT) model that describes a linear mass transfer process where the transfer kinetics and late-time transport behavior are controlled by properties of the host medium, especially the immobile domain. The intrinsic connection between the MRMT and TTLM models helps to estimate the main time-nonlocal parameters in the TTLM model (which are the time scale index, the capacity coefficient, and the truncation parameter) either semi-analytically or empirically from the measurable aquifer properties. Further applications show that the TTLM model captures the observed solute snapshots, the breakthrough curves, and the spatial moments of plumes up to the fourth order. Most importantly, the a priori estimation of the time-nonlocal parameters outside of any breakthrough fitting procedure provides a reliable “blind” prediction of the late-time dynamics of subdiffusion observed in a spectrum of alluvial settings. Predictability of the time-nonlocal parameters may be due to the fact that the late-time subdiffusion is not affected by the exact location of each immobile zone, but rather is controlled by the time spent in immobile blocks surrounding the pathway of solute particles. Results also show that the effective dispersion coefficient has to be fitted due to the scale effect of transport, and the mean velocity can differ from local measurements or volume averages. The link between medium heterogeneity and time-nonlocal parameters will help to improve model predictability for non

  12. United States Transportation Command 2001 Annual Command Report: Transforming Global Mobility ... and Distribution

    DTIC Science & Technology

    2001-01-01

    significant development of the past year, JICTRANS created and fielded the Port and Airfield Collaborative Environment—an extremely effective Secret Internet ...goal is to have all MTMC customers and industry partners access MTMC transportation services via the web through a single internet portal. Global...became the Morale, Welfare, and Recreation “ Internet Café” where troops would come to check e-mail and make telephone calls homes. It was estimated

  13. Enzyme kinetics and transport in a system crowded by mobile macromolecules.

    PubMed

    Echeverria, Carlos; Kapral, Raymond

    2015-11-21

    The dynamics of an elastic network model for the enzyme 4-oxalocrotonate tautomerase is studied in a system crowded by mobile macromolecules, also modeled by elastic networks. The system includes a large number of solvent molecules, as well as substrate and product molecules which undergo catalytic reactions with this hexameric protein. The time evolution of the entire system takes place through a hybrid dynamics that combines molecular dynamics for solute species and multiparticle collision dynamics for the solvent. It is shown that crowding leads to subdiffusive dynamics for the protein, in accord with many studies of diffusion in crowded environments, and increases orientational relaxation times. The enzyme reaction kinetics is also modified by crowding. The effective Michaelis constant decreases with crowding volume fraction, and this decrease is attributed to excluded volume effects, which dominate over effects due to reduced substrate diffusion that would cause the Michaelis constant to increase.

  14. Plant rhizosphere effects on metal mobilization and transport. 1998 annual progress report

    SciTech Connect

    Fan, T.W.M.

    1998-06-01

    'Information on the mechanism of how plants mobilize, uptake, and metabolize metal ions is very limited. Especially deficient is the understanding of these processes involving pollutant metal ions and interactions among these ions. Based on the current knowledge regarding nutrient ions, it is clear that elucidation of rhizospheric processes such as exudation of organic ligands by plant roots and plant metabolism/adaptation involving these biogenic chelators is critically important. A mechanistic insight into these processes will advance knowledge in microbe-plant host interactions and how metal ions are mobilized, immobilized, and sequestered by these interactions. This, in turn, is essential to applications such as phytobioremediation and microbioremediation of metal ion pollution. Root exudation also serves many other important rhizosphere functions including energy supply for microbial degradation of organic pollutants, structuring of microbial community, and the formation of soil humic materials which are considered to be a major sink for both organic and inorganic pollutants. How root exudates function is critically dependent on the chemical nature of exudate components. Therefore, a comprehensive characterization of all major exudate components, regardless of their chemical class, should facilitate the development and implementation of bioremediation for both organic and inorganic pollutants. Therefore, the objectives of this project are: (1) To obtain a comprehensive composition of major organic components in plant root exudates as a function of different metal ions; (2) To examine plant metabolic response(s) to these metal ion treatments, with emphasis on biosynthetic pathways of organic ligands; and (3) To investigate the effect(s) of soil microbial (e.g. mycorrhizae) association on (1) and (2).'

  15. Vegetation-derived insights on the mobilization and potential transport of radionuclides from the Nopal I natural analog site, Mexico

    SciTech Connect

    Leslie, B.W.; Pickett, D.A.; Pearcy, E.C.

    1999-07-01

    The Nopal I uranium (U) deposit, Pena Blanca, Mexico is a source term and contaminant transport natural analog to the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. In an attempt to characterize the mobilization and potential transport of radionuclides in the unsaturated zone at the Nopal I deposit, vegetation growing on ore piles was analyzed for {sup 238}U, {sup 235}U, and {sup 232}Th decay-series isotopes. Specimens of Phacelia robusta growing on high-grade piles of U ore were collected and analyzed by alpha autoradiography, and by alpha and gamma spectrometry. Activities for U, thorium (Th), and radium (Ra) isotopes (Bq/kg dried plant) were 300, 1,000, and 7,000 for {sup 238}U, {sup 230}Th, and {sup 226}Ra, respectively. The {sup 226}Ra activities in these specimens are among the highest ever measured for plants; furthermore, the plant-to-soil {sup 226}Ra concentration ratio is higher than expected. These results demonstrate the large mobility and bio-availability of Ra in the Nopal I environment, and support previous indications of recent loss of {sup 226}Ra from the ore body. Comparison between the activities of {sup 238}U and {sup 232}Th decay-chain Th isotopes in the plants and in the ore substrate indicate that relative mobilization into pore solutions of {sup 228}Th > {sup 230}Th > {sup 232}Th, in a ratio of about 50--25:4:1, respectively. The similarity of the plant's {sup 234}U/{sup 238}U activity ratio ({approximately}1.2) to that of a caliche deposit that formed adjacent to the Nopal ore body around 54 ka suggests the {sup 234}U/{sup 238}U activity ratio of U released from the ore is approximately 1.2. The U and {sup 226}Ra isotope activities of the plants and ore substrate, and solubility considerations, are used to assess a source term model of the potential Yucca Mountain repository. These results suggest the use of a natural analog source term model in performance assessments may be non-conservative.

  16. Betatron Application in Mobile and Relocatable Inspection Systems for Freight Transport Control

    NASA Astrophysics Data System (ADS)

    Chakhlov, S. V.; Kasyanov, S. V.; Kasyanov, V. A.; Osipov, S. P.; Stein, M. M.; Stein, A. M.; Xiaoming, Sun

    2016-01-01

    Accelerators with energy level up to 4 MeV having high level of penetration ability by steel equivalent are the popular to control oversize cargo transported by road, by railway and by river. Betatron's usage as cyclic induction accelerator has some advantages in comparison with linear accelerators and other sources. Tomsk Polytechnic University has developed many types of betatrons, most of them are being produced by separate affiliated company " Foton ". Article is shown the results of application of the betatrons in inspection custom systems.

  17. Transport of fluorescent bile acids by the isolated perfused rat liver: kinetics, sequestration, and mobilization.

    PubMed

    Holzinger, F; Schteingart, C D; Ton-Nu, H T; Cerrè, C; Steinbach, J H; Yeh, H Z; Hofmann, A F

    1998-08-01

    Hepatocyte transport of six fluorescent bile acids containing nitrobenzoxadiazolyl (NBD) or a fluorescein derivative on the side chain was compared with that of natural bile acids using the single-pass perfused rat liver. Compounds were infused at 40 nmol/g liver min for 15 minutes; hepatic uptake and biliary recovery were measured; fractional extraction, intrinsic basolateral clearance, and sequestration (nonrecovery after 45 minutes of additional perfusion) were calculated. Fluorescent bile acids were efficiently extracted during the first 3 minutes (70%-97%), but net extraction decreased with time mostly because of regurgitation into the perfusate. For cholylglycine and ursodeoxycholylglycine (UDC-glycine), extraction was 94% to 99%, and regurgitation did not occur. Intrinsic hepatic clearance of fluorescent bile acids (2-7 mL/g liver x min) was lower than that of cholylglycine (9.0 +/- 0.6; mean +/- SD) and UDC-glycine (21.4 +/- 0.4). Sequestration at 60 minutes was 8% to 26% for fluorescent bile acids with a cholyl moiety (cholylglycylaminofluorescein [CGamF], cholyllysylfluorescein [C-L-F], cholyl-[N epsilon-NBD]-lysine [C-L-NBD], and cholylaminofluorescein [CamF]), 32% for ursodeoxycholylaminofluorescein (UDCamF), and 88% for ursodeoxycholyl-(N epsilon-NBD)lysine (UDC-L-NBD). Cholylglycine and UDC-glycine had <3% retention. Biliary secretion of sequestered UDCamF, but not of UDC-L-NBD, was induced by adding dibutyryl cyclic adenosine monophosphate (DBcAMP) to the perfusate, possibly by translocation to the canaliculus of pericanalicular vesicles containing fluorescent bile acids. Biliary secretion of UDC-L-NBD, but not of UDCamF, was induced by adding cholyltaurine or UDC-taurine, possibly by inhibition of binding to intracellular constituents or of transport into organelles. It is concluded that fluorescent bile acids are efficiently transported across the basolateral membrane, but in contrast to natural conjugated bile acids, are sequestered in the

  18. 41 CFR 302-10.203 - What are my allowances when a mobile home is transported partly by commercial carrier and partly...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false What are my allowances when a mobile home is transported partly by commercial carrier and partly by POV? 302-10.203 Section 302-10.203 Public Contracts and Property Management Federal Travel Regulation System...

  19. 41 CFR 302-10.3 - What is the maximum amount my agency may authorize me to receive for transporting a mobile home?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false What is the maximum amount my agency may authorize me to receive for transporting a mobile home? 302-10.3 Section 302-10.3 Public Contracts and Property Management Federal Travel Regulation System RELOCATION...

  20. 41 CFR 302-10.3 - What is the maximum amount my agency may authorize me to receive for transporting a mobile home?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 4 2013-07-01 2012-07-01 true What is the maximum amount my agency may authorize me to receive for transporting a mobile home? 302-10.3 Section 302-10.3 Public Contracts and Property Management Federal Travel Regulation System RELOCATION...

  1. 41 CFR 302-10.206 - May my agency assume direct responsibility for the costs of preparing and transporting my mobile...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false May my agency assume direct responsibility for the costs of preparing and transporting my mobile home? 302-10.206 Section 302-10.206 Public Contracts and Property Management Federal Travel Regulation System...

  2. 41 CFR 302-10.200 - What costs are allowable when a commercial carrier transports my mobile home overland or over water?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false What costs are allowable when a commercial carrier transports my mobile home overland or over water? 302-10.200 Section 302-10.200 Public Contracts and Property Management Federal Travel Regulation System RELOCATION...

  3. Imaging geochemical heterogeneities using inverse reactive transport modeling: An example relevant for characterizing arsenic mobilization and distribution

    NASA Astrophysics Data System (ADS)

    Fakhreddine, Sarah; Lee, Jonghyun; Kitanidis, Peter K.; Fendorf, Scott; Rolle, Massimo

    2016-02-01

    The spatial distribution of reactive minerals in the subsurface is often a primary factor controlling the fate and transport of contaminants in groundwater systems. However, direct measurement and estimation of heterogeneously distributed minerals are often costly and difficult to obtain. While previous studies have shown the utility of using hydrologic measurements combined with inverse modeling techniques for tomography of physical properties including hydraulic conductivity, these methods have seldom been used to image reactive geochemical heterogeneities. In this study, we focus on As-bearing reactive minerals as aquifer contaminants. We use synthetic applications to demonstrate the ability of inverse modeling techniques combined with mechanistic reactive transport models to image reactive mineral lenses in the subsurface and quantify estimation error using indirect, commonly measured groundwater parameters. Specifically, we simulate the mobilization of arsenic via kinetic oxidative dissolution of As-bearing pyrite due to dissolved oxygen in the ambient groundwater, which is an important mechanism for arsenic release in groundwater both under natural conditions and engineering applications such as managed aquifer recharge and recovery operations. The modeling investigation is carried out at various scales and considers different flow-through domains including (i) a 1D lab-scale column (80 cm), (ii) a 2D lab-scale setup (60 cm × 30 cm) and (iii) a 2D field-scale domain (20 m × 4 m). In these setups, synthetic dissolved oxygen data and forward reactive transport simulations are used to image the spatial distribution of As-bearing pyrite using the Principal Component Geostatistical Approach (PCGA) for inverse modeling.

  4. Thermoelectric transport in Cu7PSe6 with high copper ionic mobility.

    PubMed

    Weldert, Kai S; Zeier, Wolfgang G; Day, Tristan W; Panthöfer, Martin; Snyder, G Jeffrey; Tremel, Wolfgang

    2014-08-27

    Building on the good thermoelectric performances of binary superionic compounds like Cu2Se, Ag2Se and Cu2S, a better and more detailed understanding of phonon-liquid electron-crystal (PLEC) thermoelectric materials is desirable. In this work we present the thermoelectric transport properties of the compound Cu7PSe6 as the first representative of the class of argyrodite-type ion conducting thermoelectrics. With a huge variety of possible compositions and high ionic conductivity even at room temperature, the argyrodites represent a very good model system to study structure-property relationships for PLEC thermoelectric materials. We particularly highlight the extraordinary low thermal conductivity of Cu7PSe6 below the glass limit, which can be associated with the molten copper sublattice leading to a softening of phonon modes.

  5. Removing traffic emissions from CO2 time series measured at a tall tower using mobile measurements and transport modeling

    NASA Astrophysics Data System (ADS)

    Schmidt, Andres; Rella, Chris W.; Göckede, Mathias; Hanson, Chad; Yang, Zhenlin; Law, Beverly E.

    2014-11-01

    In recent years, measurements of atmospheric carbon dioxide with high precision and accuracy have become increasingly important for climate change research, in particular to inform terrestrial biosphere models. Anthropogenic carbon dioxide emissions from fossil fuel burning have long been recognized to contribute a significant portion of the carbon dioxide in the atmosphere. Here, we present an approach to remove the traffic related carbon dioxide emissions from mole fractions measured at a tall tower by using the corresponding carbon monoxide measurements in combination with footprint analyses and transport modeling. This technique improves the suitability of the CO2 data to be used in inverse modeling approaches of atmosphere-biosphere exchange that do not account for non-biotic portions of CO2. In our study region in Oregon, road traffic emissions are the biggest source of anthropogenic carbon dioxide and carbon monoxide. A three-day mobile campaign covering 1700 km of roads in northwestern Oregon was performed during summer of 2012 using a laser-based Cavity Ring-Down Spectrometer. The mobile measurements incorporated different roads including main highways, urban streets, and back-roads, largely within the typical footprint of a tall CO/CO2 observation tower in Oregon's Willamette Valley. For the first time, traffic related CO:CO2 emission ratios were measured directly at the sources during an on-road campaign under a variety of different driving conditions. An average emission ratio of 7.43 (±1.80) ppb CO per ppm CO2 was obtained for the study region and applied to separate the traffic related portion of CO2 from the mole fraction time series. The road traffic related portion of the CO2 mole fractions measured at the tower site reached maximum values ranging from 9.8 to 12 ppm, depending on the height above the surface, during summer 2012.

  6. Dust mobilization and transport in the northern Sahara during SAMUM 2006 - a meteorological overview

    NASA Astrophysics Data System (ADS)

    Knippertz, Peter; Ansmann, Albert; Althausen, Dietrich; Müller, Detlef; Tesche, Matthias; Bierwirth, Eike; Dinter, Tilman; Müller, Thomas; von Hoyningen-Huene, Wolfgang; Schepanski, Kerstin; Wendisch, Manfred; Heinold, Bernd; Kandler, Konrad; Petzold, Andreas; Schütz, Lothar; Tegen, Ina

    2009-02-01

    ABSTRACT The SAMUM field campaign in southern Morocco in May/June 2006 provides valuable data to study the emission, and the horizontal and vertical transports of mineral dust in the Northern Sahara. Radiosonde and lidar observations show differential advection of air masses with different characteristics during stable nighttime conditions and up to 5-km deep vertical mixing in the strongly convective boundary layer during the day. Lagrangian and synoptic analyses of selected dust periods point to a topographic channel from western Tunisia to central Algeria as a dust source region. Significant emission events are related to cold surges from the Mediterranean in association with eastward passing upper-level waves and lee cyclogeneses south of the Atlas Mountains. Other relevant events are local emissions under a distinct cut-off low over northwestern Africa and gust fronts associated with dry thunderstorms over the Malian and Algerian Sahara. The latter are badly represented in analyses from the European Centre for Medium-Range Weather Forecasts and in a regional dust model, most likely due to problems with moist convective dynamics and a lack of observations in this region. This aspect needs further study. The meteorological source identification is consistent with estimates of optical and mineralogical properties of dust samples.

  7. Efforts to Reduce International Space Station Crew Maintenance for the Management of the Extravehicular Mobility Unit Transport Loop Water Quality

    NASA Technical Reports Server (NTRS)

    Steele, John W.; Etter, David; Rector, Tony; Boyle, Robert; Vandezande, Christopher

    2013-01-01

    The EMU (Extravehicular Mobility Unit) contains a semi-closed-loop re-circulating water circuit (Transport Loop) to absorb heat into a LCVG (Liquid Coolant and Ventilation Garment) worn by the astronaut. A second, single-pass water circuit (Feed-water Loop) provides water to a cooling device (Sublimator) containing porous plates, and that water sublimates through the porous plates to space vacuum. The cooling effect from the sublimation of this water translates to a cooling of the LCVG water that circulates through the Sublimator. The quality of the EMU Transport Loop water is maintained through the use of a water processing kit (ALCLR Airlock Cooling Loop Remediation) that is used to periodically clean and disinfect the water circuit. Opportunities to reduce crew time associated with on-orbit ALCLR operations include a detailed review of the historical water quality data for evidence to support an extension to the implementation cycle. Furthermore, an EMU returned after 2-years of use on the ISS (International Space Station) is being used as a test bed to evaluate the results of extended and repeated ALCLR implementation cycles. Finally, design, use and on-orbit location enhancements to the ALCLR kit components are being considered to allow the implementation cycle to occur in parallel with other EMU maintenance and check-out activities, and to extend the life of the ALCLR kit components. These efforts are undertaken to reduce the crew-time and logistics burdens for the EMU, while ensuring the long-term health of the EMU water circuits for a post-Shuttle 6-year service life.

  8. Imaging reactive minerals in the subsurface using inverse reactive transport modeling: an example relevant for arsenic mobilization

    NASA Astrophysics Data System (ADS)

    Fakhreddine, S.; Lee, J. H.; Kitanidis, P. K.; Fendorf, S. E.; Rolle, M.

    2014-12-01

    The spatial distribution of naturally occurring, arsenic-bearing minerals in the subsurface is a key factor for determining the fate and transport of arsenic in groundwater systems. However, the direct measurement and estimation of these heterogeneously distributed minerals are often costly and difficult to obtain. While previous studies have shown the utility of using indirect measurements combined with inverse modeling techniques for tomography of physical properties including hydraulic conductivity, these methods have seldom been used to image geochemical properties. In this study, we use synthetic applications to demonstrate the ability of inverse modeling techniques to image reactive mineral lenses in the subsurface and quantify estimation error using indirect, commonly measured groundwater parameters. Specifically, we simulate the mobilization of arsenic via kinetic oxidative dissolution of arsenopyrite due to dissolved oxygen in the ambient groundwater. The modeling investigation is carried out at various scales and considers different flow-through domains including (i) a 1D lab-scale column (80 cm), (ii) a 2D lab-scale setup (30 cm x 60 cm) and (iii) a 2D field-scale domain (4 m x 20 m). Next, the simulated dissolved oxygen data and forward reactive transport model are used to image the spatial distribution of arsenopyrite using the Principal Component Geostatistical Approach (PCGA) for inverse modeling. The PCGA is a matrix-free geostatistical inversion approach that uses the leading principal components of the prior information to save computational costs and can be easily linked with any simulation software. Our results show that the PCGA can be used to image randomly distributed arsenopyrite lenses at various scales and has the potential to be employed at the field-scale to map complex distributions of reactive minerals in the subsurface based on the measurement of dissolved constituents in groundwater.

  9. Design of an eMonitor system to transport electronic patient care report (ePCR) information in unstable MobileIP wireless environment.

    PubMed

    Giovanni, Mazza G; Shenvi, Rohit; Battles, Marcie; Orthner, Helmuth F

    2008-11-06

    The eMonitor is a component of the ePatient system; a prototype system used by emergency medical services (EMS) personnel in the field to record and transmits electronic patient care report (ePCR) information interactively. The eMonitor component allows each Mobile Data Terminal (MDT) on an unreliable Cisco MobileIP wireless network to securely send and received XML messages used to update patient information to and from the MDT before, during and after the transport of a patient.

  10. Tests of an alternate mobile transporter and extravehicular activity assembly procedure for the Space Station Freedom truss

    NASA Technical Reports Server (NTRS)

    Heard, Walter L., Jr.; Watson, Judith J.; Lake, Mark S.; Bush, Harold G.; Jensen, J. Kermit; Wallsom, Richard E.; Phelps, James E.

    1992-01-01

    Results are presented from a ground test program of an alternate mobile transporter (MT) concept and extravehicular activity (EVA) assembly procedure for the Space Station Freedom (SSF) truss keel. A three-bay orthogonal tetrahedral truss beam consisting of 44 2-in-diameter struts and 16 nodes was assembled repeatedly in neutral buoyancy by pairs of pressure-suited test subjects working from astronaut positioning devices (APD's) on the MT. The truss bays were cubic with edges 15 ft long. All the truss joint hardware was found to be EVA compatible. The average unit assembly time for a single pair of experienced test subjects was 27.6 sec/strut, which is about half the time derived from other SSF truss assembly tests. A concept for integration of utility trays during truss assembly is introduced and demonstrated in the assembly tests. The concept, which requires minimal EVA handling of the trays, is shown to have little impact on overall assembly time. The results of these tests indicate that by using an MT equipped with APD's, rapid EVA assembly of a space station-size truss structure can be expected.

  11. An analysis of selection on candidate genes for regulation, mobilization, uptake, and transport of iron in maize.

    PubMed

    Benke, Andreas; Stich, Benjamin

    2011-08-01

    Insufficient iron (Fe) availability, which frequently occurs in soils with high pH levels, can lead to leaf chlorosis, a reduced Fe content in harvest products, and yield reduction in maize. The objectives of this study were (i) to describe patterns of sequence variation of 14 candidate genes for mobilization, uptake, and transport of Fe in maize, as well as regulatory function on these processes; (ii) to examine whether Fe-efficiency is an adaptive trait by determining if these genes were targets of selection during domestication; and (iii) to test if the allele distribution at these candidate genes is different for the different subpopulations of maize. The nucleotide diversity of Mtk was reduced by 78% in maize compared with teosinte. The results of our study revealed for the genes Naat1, Nas1, Nramp3, Mtk, and Ys1 a selective sweep, which suggests that these genes might be important for the fast adaptation of maize to new environments with different Fe availabilities.

  12. Evaluating the mobility of polymer-stabilised zero-valent iron nanoparticles and their potential to co-transport contaminants in intact soil cores.

    PubMed

    Chekli, L; Brunetti, G; Marzouk, E R; Maoz-Shen, A; Smith, E; Naidu, R; Shon, H K; Lombi, E; Donner, E

    2016-09-01

    The use of zero-valent iron nanoparticles (nZVI) has been advocated for the remediation of both soils and groundwater. A key parameter affecting nZVI remediation efficacy is the mobility of the particles as this influences the reaction zone where remediation can occur. However, by engineering nZVI particles with increased stability and mobility we may also inadvertently facilitate nZVI-mediated contaminant transport away from the zone of treatment. Previous nZVI mobility studies have often been limited to model systems as the presence of background Fe makes detection and tracking of nZVI in real systems difficult. We overcame this problem by synthesising Fe-59 radiolabelled nZVI. This enabled us to detect and quantify the leaching of nZVI-derived Fe-59 in intact soil cores, including a soil contaminated by Chromated-Copper-Arsenate. Mobility of a commercially available nZVI was also tested. The results showed limited mobility of both nanomaterials; <1% of the injected mass was eluted from the columns and most of the radiolabelled nZVI remained in the surface soil layers (the primary treatment zone in this contaminated soil). Nevertheless, the observed breakthrough of contaminants and nZVI occurred simultaneously, indicating that although the quantity transported was low in this case, nZVI does have the potential to co-transport contaminants. These results show that direct injection of nZVI into the surface layers of contaminated soils may be a viable remediation option for soils such as this one, in which the mobility of nZVI below the injection/remediation zone was very limited. This Fe-59 experimental approach can be further extended to test nZVI transport in a wider range of contaminated soil types and textures and using different application methods and rates. The resulting database could then be used to develop and validate modelling of nZVI-facilitated contaminant transport on an individual soil basis suitable for site specific risk assessment prior to n

  13. TRANSPORT

    EPA Science Inventory

    Presentation outline: transport principles, effective solubility; gasoline composition; and field examples (plume diving).
    Presentation conclusions: MTBE transport follows from - phyiscal and chemical properties and hydrology. Field examples show: MTBE plumes > benzene plu...

  14. A Static and Dynamic Investigation of Quantum Nonlinear Transport in Highly Dense and Mobile 2D Electron Systems

    NASA Astrophysics Data System (ADS)

    Dietrich, Scott

    Heterostructures made of semiconductor materials may be one of most versatile environments for the study of the physics of electron transport in two dimensions. These systems are highly customizable and demonstrate a wide range of interesting physical phenomena. In response to both microwave radiation and DC excitations, strongly nonlinear transport that gives rise to non-equilibrium electron states has been reported and investigated. We have studied GaAs quantum wells with a high density of high mobility two-dimensional electrons placed in a quantizing magnetic field. This study presents the observation of several nonlinear transport mechanisms produced by the quantum nature of these materials. The quantum scattering rate, 1tau/q, is an important parameter in these systems, defining the width of the quantized energy levels. Traditional methods of extracting 1tau/q involve studying the amplitude of Shubnikov-de Haas oscillations. We analyze the quantum positive magnetoresistance due to the cyclotron motion of electrons in a magnetic field. This method gives 1tau/q and has the additional benefit of providing access to the strength of electron-electron interactions, which is not possible by conventional techniques. The temperature dependence of the quantum scattering rate is found to be proportional to the square of the temperature and is in very good agreement with theory that considers electron-electron interactions in 2D systems. In quantum wells with a small scattering rate - which corresponds to well-defined Landau levels - quantum oscillations of nonlinear resistance that are independent of magnetic field strength have been observed. These oscillations are periodic in applied bias current and are connected to quantum oscillations of resistance at zero bias: either Shubnikov-de Haas oscillations for single subband systems or magnetointersubband oscillations for two subband systems. The bias-induced oscillations can be explained by a spatial variation of electron

  15. Literature review for Texas Department of Transportation Research Project 0-4695: Guidance for design in areas of extreme bed-load mobility, Edwards Plateau, Texas

    USGS Publications Warehouse

    Heitmuller, Franklin T.; Asquith, William H.; Fang, Xing; Thompson, David B.; Wang, Keh-Han

    2005-01-01

    A review of the literature addressing sediment transport in gravel-bed river systems and structures designed to control bed-load mobility is provided as part of Texas Department of Transportation research project 0–4695: Guidance for Design in Areas of Extreme Bed-Load Mobility. The study area comprises the western half of the Edwards Plateau in central Texas. Three primary foci of the literature review are journal articles, edited volumes, and government publications. Major themes within the body of literature include deterministic sediment transport theory and equations, development of methods to measure and analyze fluvial sediment, applications and development of theory in natural channels and flume experiments, and recommendations for river management and structural design. The literature review provides an outline and foundation for the research project to characterize extreme bed-load mobility in rivers and streams across the study area. The literature review also provides a basis upon which potential modifications to low-water stream-crossing design in the study area can be made.

  16. Mobile Router Technology Development

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Stewart, David H.; Bell, Terry L.; Kachmar, Brian A.; Shell, Dan; Leung, Kent

    2002-01-01

    Cisco Systems and NASA have been performing joint research on mobile routing technology under a NASA Space Act Agreement. Cisco developed mobile router technology and provided that technology to NASA for applications to aeronautic and space-based missions. NASA has performed stringent performance testing of the mobile router, including the interaction of routing and transport-level protocols. This paper describes mobile routing, the mobile router, and some key configuration parameters. In addition, the paper describes the mobile routing test network and test results documenting the performance of transport protocols in dynamic routing environments.

  17. Direct Numerical Simulation of a Shocked Helium Jet

    SciTech Connect

    Cloutman, L D

    2002-02-01

    We present direct numerical simulations of a shock tube experiment in which a cylindrical laminar jet of helium doped with biacetyl is injected into air and subjected to a weak shock wave. Computed species distributions in a planar cross section of the jet are compared to planar laser-induced fluorescence (PLIF) images produced by the experiment. The calculations are in excellent agreement with the experimental images. We find that differential diffusion of species is an important feature of this experiment.

  18. Characterization of gaseous helium jet dispersion to atmosphere

    NASA Astrophysics Data System (ADS)

    Khan, H. J.; Figueroa, O.; Rhee, M.

    A major ground-based experiment to be performed for the Superfluid Helium On Orbit Transfer (SHOOT) program is the accidental loss of the vacuum guard of the super-insulated dewar. The design of the dewar vent-path requires adequate mass removal after a preset pressure is reached due to external heat transfer. The existing helium creates a turbulent buoyant jet, expanding in air with entrainment of the jet interface to the surrounding. Transient analysis is performed for axial and radial jet temperature prediction using the self-similarity assumption applied to mass, momentum, and the energy-balance equations of helium. The predicted jet temperature profiles with vertical and radial expansion up to 1.6 and 1.0 m, respectively, demonstrate the low temperature core established by gaseous helium. For all time steps, the axial and radial temperature predictions are observed to be within 8 and 20 percent, respectively.

  19. Electronic transport in a model tetraphenylbenzidine main-chain polymer: Direct comparison of time-of-flight hole drift mobility and electrochemical determinations of hole diffusion

    NASA Astrophysics Data System (ADS)

    Abkowitz, M. A.; Facci, J. S.; Limburg, W. W.; Yanus, J. F.

    1992-09-01

    Electronic transport behavior is analyzed in a model polytetraphenylbenzidine (PTPB) hole transport polymer in which electroactive tetraphenylbenzidine sites are covalently bonded within the polymer main chain. Time-of-flight (TOF) techniques are used to measure the hole drift mobility as a function of electric field and temperature. The TOF data are parametrized using the phenomenological model originally proposed by Gill. For comparative purposes, the disorder model developed by the Marburg group is also used to analyze the data. Transport of holes in PTPB is demonstrated to occur via hopping among the TPB functional units. A pattern of convoluted field and temperature-dependent features, now known to be shared by a broad class of disordered molecular materials, is revealed by the TOF data. Thin solid film electrochemical techniques are applied in parallel with the TOF technique to independently obtain hole diffusion coefficients (Dh) in thin films of PTPB. As a unique consequence of this comparison, it is established that mobilities, computed from solid-state hole diffusion data using the Einstein relation, converge with zero-field extrapolated TOF mobilities over a wide temperature range when the extrapolation is computed from log μ vs E1/2 plots. Therefore, the functional dependence of the logarithm of the drift mobility on the square root of field, a much discussed general feature of electronic transport in disordered molecular materials, is demonstrated to persist through the critical low-field limit. At the same time it is demonstrated that the contribution of thermally driven diffusive broadening, which can now be calculated directly from the independently determined electrochemical hole diffusion coefficients, makes an insignificant contribution to the experimentally observed width of the time-of-flight transit pulse. A comparison of the PTPB data with analogous TOF data on solid solutions of TPD (the functional unit in PTPB) dispersed in polycarbonate

  20. High mobility, large linear magnetoresistance, and quantum transport phenomena in Bi2Te3 films grown by metallo-organic chemical vapor deposition (MOCVD).

    PubMed

    Jin, Hyunwoo; Kim, Kwang-Chon; Seo, Juhee; Kim, Seong Keun; Cheong, Byung-Ki; Kim, Jin-Sang; Lee, Suyoun

    2015-11-07

    We investigated the magnetotransport properties of Bi2Te3 films grown on GaAs (001) substrate by a cost-effective metallo-organic chemical vapor deposition (MOCVD). We observed the remarkably high carrier mobility and the giant linear magnetoresistance (carrier mobility ∼ 22 000 cm(2) V(-1) s(-1), magnetoresistance ∼ 750% at 1.8 K and 9 T for a 100 nm thick film) that depends on the film thickness. In addition, the Shubnikov-de Haas oscillation was observed, from which the effective mass was calculated to be consistent with the known value. From the thickness dependence of the Shubnikov-de Haas oscillation, it was found that a two dimensional electron gas with the conventional electron nature coexists with the topological Dirac fermion states and dominates the carrier transport in the Bi2Te3 film with thickness higher than 300 nm. These results are attributed to the intrinsic nature of Bi2Te3 in the high-mobility transport regime obtained by a deliberate choice of the substrate and the growth conditions.

  1. Mobility and transport of mercury and methylmercury in peat as a function of changes in water table regime and plant functional groups

    NASA Astrophysics Data System (ADS)

    Haynes, Kristine M.; Kane, Evan S.; Potvin, Lynette; Lilleskov, Erik A.; Kolka, Randall K.; Mitchell, Carl P. J.

    2017-02-01

    Climate change is likely to significantly affect the hydrology, ecology, and ecosystem function of peatlands, with potentially important but unclear impacts on mercury mobility within and transport from peatlands. Using a full-factorial mesocosm approach, we investigated the potential impacts on mercury mobility of water table regime changes (high and low) and vegetation community shifts (sedge-dominated, Ericaceae-dominated, or unmanipulated control) in peat monoliths at the PEATcosm mesocosm facility in Houghton, Michigan. Lower and more variable water table regimes and the loss of Ericaceae shrubs act significantly and independently to increase both total Hg and methylmercury concentrations in peat pore water and in spring snowmelt runoff. These differences are related to enhanced peat decomposition and internal regeneration of electron acceptors which are more strongly related to water table regime than to plant community changes. Loss of Ericaceae shrubs and an increase in sedge cover may also affect Hg concentrations and mobility via oxygen shuttling and/or the provision of labile root exudates. Altered hydrological regimes and shifting vegetation communities, as a result of global climate change, are likely to enhance Hg transport from peatlands to downstream aquatic ecosystems.

  2. Interplay between hopping and band transport in high-mobility disordered semiconductors at large carrier concentrations: The case of the amorphous oxide InGaZnO

    NASA Astrophysics Data System (ADS)

    Fishchuk, I. I.; Kadashchuk, A.; Bhoolokam, A.; de Jamblinne de Meux, A.; Pourtois, G.; Gavrilyuk, M. M.; Köhler, A.; Bässler, H.; Heremans, P.; Genoe, J.

    2016-05-01

    We suggest an analytic theory based on the effective medium approximation (EMA) which is able to describe charge-carrier transport in a disordered semiconductor with a significant degree of degeneration realized at high carrier concentrations, especially relevant in some thin-film transistors (TFTs), when the Fermi level is very close to the conduction-band edge. The EMA model is based on special averaging of the Fermi-Dirac carrier distributions using a suitably normalized cumulative density-of-state distribution that includes both delocalized states and the localized states. The principal advantage of the present model is its ability to describe universally effective drift and Hall mobility in heterogeneous materials as a function of disorder, temperature, and carrier concentration within the same theoretical formalism. It also bridges a gap between hopping and bandlike transport in an energetically heterogeneous system. The key assumption of the model is that the charge carriers move through delocalized states and that, in addition to the tail of the localized states, the disorder can give rise to spatial energy variation of the transport-band edge being described by a Gaussian distribution. It can explain a puzzling observation of activated and carrier-concentration-dependent Hall mobility in a disordered system featuring an ideal Hall effect. The present model has been successfully applied to describe experimental results on the charge transport measured in an amorphous oxide semiconductor, In-Ga-Zn-O (a-IGZO). In particular, the model reproduces well both the conventional Meyer-Neldel (MN) compensation behavior for the charge-carrier mobility and inverse-MN effect for the conductivity observed in the same a-IGZO TFT. The model was further supported by ab initio calculations revealing that the amorphization of IGZO gives rise to variation of the conduction-band edge rather than to the creation of localized states. The obtained changes agree with the one we

  3. Equivalence between the mobility edge of electronic transport on disorderless networks and the onset of chaos via intermittency in deterministic maps.

    PubMed

    Martínez-Mares, M; Robledo, A

    2009-10-01

    We exhibit a remarkable equivalence between the dynamics of an intermittent nonlinear map and the electronic transport properties (obtained via the scattering matrix) of a crystal defined on a double Cayley tree. This strict analogy reveals in detail the nature of the mobility edge normally studied near (not at) the metal-insulator transition in electronic systems. We provide an analytical expression for the conductance as a function of the system size that at the transition obeys a q-exponential form. This manifests as power-law decay or few and far between large spike oscillations according to different kinds of boundary conditions.

  4. Transport Imaging of Spatial Distribution of Mobility-Lifetime (Micro Tau) Product in Bulk Semiconductors for Nuclear Radiation Detection

    DTIC Science & Technology

    2012-06-01

    transport imaging using the electron beam from the SEM and an external CCD array camera . .........................................15  Figure 5.  System...schematic for transport imaging using the electron beam from the SEM and an external CCD array camera ...Intensity, as measured by counts recorded on the CCD array camera , and (b) Normalized scale, with each distribution normalized to its own maximum

  5. Mn-euvering manganese: the role of transporter gene family members in manganese uptake and mobilization in plants

    PubMed Central

    Socha, Amanda L.; Guerinot, Mary Lou

    2014-01-01

    Manganese (Mn), an essential trace element, is important for plant health. In plants, Mn serves as a cofactor in essential processes such as photosynthesis, lipid biosynthesis and oxidative stress. Mn deficient plants exhibit decreased growth and yield and are more susceptible to pathogens and damage at freezing temperatures. Mn deficiency is most prominent on alkaline soils with approximately one third of the world's soils being too alkaline for optimal crop production. Despite the importance of Mn in plant development, relatively little is known about how it traffics between plant tissues and into and out of organelles. Several gene transporter families have been implicated in Mn transport in plants. These transporter families include NRAMP (natural resistance associated macrophage protein), YSL (yellow stripe-like), ZIP (zinc regulated transporter/iron-regulated transporter [ZRT/IRT1]-related protein), CAX (cation exchanger), CCX (calcium cation exchangers), CDF/MTP (cation diffusion facilitator/metal tolerance protein), P-type ATPases and VIT (vacuolar iron transporter). A combination of techniques including mutant analysis and Synchrotron X-ray Fluorescence Spectroscopy can assist in identifying essential transporters of Mn. Such knowledge would vastly improve our understanding of plant Mn homeostasis. PMID:24744764

  6. Mobility of Source Zone Heavy Metals and Radionuclides: The Mixed Roles of Fermentative Activity on Fate and Transport of U and Cr. Final Report

    SciTech Connect

    Gerlach, Robin; Peyton, Brent M.; Apel, William A.

    2014-01-29

    Various U. S. Department of Energy (DOE) low and medium-level radioactive waste sites contain mixtures of heavy metals, radionuclides and assorted organic materials. In addition, there are numerous sites around the world that are contaminated with a mixture of organic and inorganic contaminants. In most sites, over time, water infiltrates the wastes, and releases metals, radionuclides and other contaminants causing transport into the surrounding environment. We investigated the role of fermentative microorganisms in such sites that may control metal, radionuclide and organics migration from source zones. The project was initiated based on the following overarching hypothesis: Metals, radionuclides and other contaminants can be mobilized by infiltration of water into waste storage sites. Microbial communities of lignocellulose degrading and fermenting microorganisms present in the subsurface of contaminated DOE sites can significantly impact migration by directly reducing and immobilizing metals and radionuclides while degrading complex organic matter to low molecular weight organic compounds. These low molecular weight organic acids and alcohols can increase metal and radionuclide mobility by chelation (i.e., certain organic acids) or decrease mobility by stimulating respiratory metal reducing microorganisms. We demonstrated that fermentative organisms capable of affecting the fate of Cr6+, U6+ and trinitrotoluene can be isolated from organic-rich low level waste sites as well as from less organic rich subsurface environments. The mechanisms, pathways and extent of contaminant transformation depend on a variety of factors related to the type of organisms present, the aqueous chemistry as well as the geochemistry and mineralogy. This work provides observations and quantitative data across multiple scales that identify and predict the coupled effects of fermentative carbon and electron flow on the transport of radionuclides, heavy metals and organic contaminants in

  7. Effect of Clay Nanoparticle Transport, Desorption Kinetics and Redox Equilibrium on Radionuclide Mobility in Fractured Rock investigated at the Grimsel Test Site (Switzerland)

    NASA Astrophysics Data System (ADS)

    Schaefer, T.; Huber, F. M.; Lagos, M.; Quinto, F.; Heck, S.; Martin, A. J.; Blechschmidt, I.; Lanyon, G. W.; Reiche, T.; Noseck, U.

    2015-12-01

    Transport of contaminants in crystalline environments might occur through dissolved species or attached to colloidal or nanoparticulate phases being mobile in water conducting features of the host rock. In this presentation we will discuss the mobility of clay nanoparticles as detected by laser-induced breakdown detection (LIBD) as a function of fracture surface roughness and groundwater chemistry. The on site observed Tc-99, U-233, Np-237, Pu-242 and Am-243 sorption/desorption kinetics with and without natural or synthetic clay minerals (smectites) are compared to laboratory studies under similar groundwater conditions. The desorption or redox kinetics were monitored over a duration of up to 426 days using natural fracture filling material as a concurrence ligand and monitoring the colloid attachment via detection of Al, Si, Ni and Zn as smectite structural elements. For trivalent actinides smectite desorption rates in the range of 1.2-3.7E-3 per hour could be determined and significantly lower desorption rates for tetravalent actinides were found. This results will be compared with field data of migration experiments performed at the Grimsel Test Site (GTS, Switzerland) using the same radionuclides and clay colloidal phases varying the fracture residence time by flow rate adjustment. Furthermore, the long-term actinide mobility will be addressed by presenting AMS/RIMS measurements of (a) samples collected several months into the tailing of the breakthrough curves not any longer detectable by HR-ICP-MS and (b) background samples of different GTS ground waters showing fallout U-236, whereas fallout Pu could not be detected indicating a much lower mobility under the given conditions.

  8. Colloids in groundwater: Their mobilization, subsurface transport, and sorption affinity for toxic chemicals. Annual technical progress report

    SciTech Connect

    Gschwend, P.M.

    1992-07-10

    Our originally stated objectives included: (1) development of a quantitative source function for colloid mobilization to groundwater, and (2) assessment of the most important colloidal phases to which nonpolar compounds sorb. We have been pursuing a series of studies to elucidate the roles of colloidal phases in subsurface environments. Most notably, we have discovered the critical role of secondary cementitious phases like goethite. We developed a new procedure for measuring ``surface iron oxides`` which is a great improvement over earlier methodologies. Currently, we are developing a unifying model with which we can predict the mobilization of colloids to groundwater flowing through such porous media. Also, we have been able to show that groundwater samples contain colloidal phases in sufficient quantities and of suitable properties to enhance the mobile load of toxic compounds like polycyclic aromatic hydrocarbons. Finally, we have synthesized our varied field investigations from sites in Massachusetts, New Jersey, Delaware, Nevada, Connecticut, and New York to yield a protocol for other researchers interested in evaluating colloids in groundwater. These accomplishments are discussed in more detail below. Through these efforts, we have become increasingly convinced of the central role played by colloidal phases in numerous subsurface phenomena controlling contaminant fates.

  9. Effect of Energy Alignment, Electron Mobility, and Film Morphology of Perylene Diimide Based Polymers as Electron Transport Layer on the Performance of Perovskite Solar Cells.

    PubMed

    Guo, Qiang; Xu, Yingxue; Xiao, Bo; Zhang, Bing; Zhou, Erjun; Wang, Fuzhi; Bai, Yiming; Hayat, Tasawar; Alsaedi, Ahmed; Tan, Zhan'ao

    2017-03-29

    For organic-inorganic perovskite solar cells (PerSCs), the electron transport layer (ETL) plays a crucial role in efficient electron extraction and transport for high performance PerSCs. Fullerene and its derivatives are commonly used as ETL for p-i-n structured PerSCs. However, these spherical small molecules are easy to aggregate with high annealing temperature and thus induce morphology stability problems. N-type conjugated polymers are promising candidates to overcome these problems due to the tunable energy levels, controllable aggregation behaviors, and good film formation abilities. Herein, a series of perylene diimide (PDI) based polymers (PX-PDIs), which contain different copolymeried units (X), including vinylene (V), thiophene (T), selenophene (Se), dibenzosilole (DBS), and cyclopentadithiophene (CPDT), are introduced as ETL for p-i-n structured PerSCs. The effect of energy alignment, electron mobility, and film morphology of these ETLs on the photovoltaic performance of the PerSCs are fully investigated. Among the PX-PDIs, PV-PDI demonstrates the deeper LUMO energy level, the highly delocalized LUMO electron density, and a better planar structure, making it the best electron transport material for PerSCs. The planar heterojunction PerSC with PV-PDI as ETL achieves a power conversion efficiency (PCE) of 10.14%, among the best values for non-fullerene based PerSCs.

  10. Water resources planning for rivers draining into Mobile Bay. Part 2: Non-conservative species transport models

    NASA Technical Reports Server (NTRS)

    April, G. C.; Liu, H. A.

    1975-01-01

    Total coliform group bacteria were selected to expand the mathematical modeling capabilities of the hydrodynamic and salinity models to understand their relationship to commercial fishing ventures within bay waters and to gain a clear insight into the effect that rivers draining into the bay have on water quality conditions. Parametric observations revealed that temperature factors and river flow rate have a pronounced effect on the concentration profiles, while wind conditions showed only slight effects. An examination of coliform group loading concentrations at constant river flow rates and temperature shows these loading changes have an appreciable influence on total coliform distribution within Mobile Bay.

  11. Transport properties of a 3D topological insulator based on a strained high-mobility HgTe film.

    PubMed

    Kozlov, D A; Kvon, Z D; Olshanetsky, E B; Mikhailov, N N; Dvoretsky, S A; Weiss, D

    2014-05-16

    We investigate the magnetotransport properties of strained 80 nm thick HgTe layers featuring a high mobility of μ ∼ 4 × 10(5) cm(2)/V · s. By means of a top gate, the Fermi energy is tuned from the valence band through the Dirac-type surface states into the conduction band. Magnetotransport measurements allow us to disentangle the different contributions of conduction band electrons, holes, and Dirac electrons to the conductivity. The results are in line with previous claims that strained HgTe is a topological insulator with a bulk gap of ≈ 15 meV and gapless surface states.

  12. Mobile Source Observation Database (MSOD)

    EPA Pesticide Factsheets

    The Mobile Source Observation Database (MSOD) is a relational database developed by the Assessment and Standards Division (ASD) of the U.S. EPA Office of Transportation and Air Quality (formerly the Office of Mobile Sources).

  13. Investigating Uranium Mobility Using Stable Isotope Partitioning of 238U/235U and a Reactive Transport Model

    NASA Astrophysics Data System (ADS)

    Bizjack, M.; Johnson, T. M.; Druhan, J. L.; Shiel, A. E.

    2015-12-01

    We report a numerical reactive transport model which explicitly incorporates the effectively stable isotopes of uranium (U) and the factors that influence their partitioning in bioactive systems. The model reproduces trends observed in U isotope ratios and concentration measurements from a field experiment, thereby improving interpretations of U isotope ratios as a tracer for U reactive transport. A major factor contributing to U storage and transport is its redox state, which is commonly influenced by the availability of organic carbon to support metal-reducing microbial communities. Both laboratory and field experiments have demonstrated that biogenic reduction of U(VI) fractionates the stable isotope ratio 238U/235U, producing an isotopically heavy solid U(IV) product. It has also been shown that other common reactive transport processes involving U do not fractionate isotopes to a consistently measurable level, which suggests the capacity to quantify the extent of bioreduction occurring in groundwater containing U using 238U/235U ratios. A recent study of a U bioremediation experiment at the Rifle IFRC site (Colorado, USA) applied Rayleigh distillation models to quantify U stable isotope fractionation observed during acetate amendment. The application of these simplified models were fit to the observations only by invoking a "memory-effect," or a constant source of low-concentration, unfractionated U(VI). In order to more accurately interpret the measured U isotope ratios, we present a multi-component reactive transport model using the CrunchTope software. This approach is capable of quantifying the cycling and partitioning of individual U isotopes through a realistic network of transport and reaction pathways including reduction, oxidation, and microbial growth. The model incorporates physical heterogeneity of the aquifer sediments through zones of decreased permeability, which replicate the observed bromide tracer, major ion chemistry, U concentration, and U

  14. The electronic transport of top subband and disordered sea in an InAs nanowire in the presence of a mobile gate.

    PubMed

    Zhukov, A A; Volk, C; Winden, A; Hardtdegen, H; Schäpers, T

    2014-04-23

    We performed measurements at helium temperatures of the electronic transport in an InAs quantum wire (R(wire) ∼ 30 kΩ) in the presence of a charged tip of an atomic force microscope serving as a mobile gate. The period and the amplitude of the observed quasi-periodic oscillations are investigated in detail as a function of electron concentration in the linear and non-linear regime. We demonstrate the influence of the tip-to-sample distance on the ability to locally affect the top subband electrons as well as the electrons in the disordered sea. Furthermore, we introduce a new method of detection of the subband occupation in an InAs wire, which allows us to evaluate the number of electrons in the conductive band of the wire.

  15. Effect of annealing on electronic carrier transport properties of gamma-irradiated AlGaN/GaN high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Yadav, Anupama; Schwarz, Casey; Shatkhin, Max; Wang, Luther; Flitsiyan, Elena; Chernyak, Leonid; Liu, Lu; Hwang, Ya; Ren, Fan; Pearton, Stephen; Department of Physics, University of Central Florida Collaboration; Department of Chemical Engineering, University of Florida Collaboration; Department of Materials Science; Engineering, University of Florida Collaboration

    2014-03-01

    AlGaN/GaN High Electron Mobility Transistors were irradiated with 60Co gamma-ray doses from 100Gy to 1000Gy, in order to analyze the effects of irradiation on the devices' transport properties. Temperature dependent Electron Beam Induced Current (EBIC) measurements, conducted on the devices before and after exposure to gamma-irradiation, allowed for the obtaining of activation energy related to radiation-induced defects due to nitrogen vacancies. Later, the devices were annealed at 200o C for 25 minutes. All the measurements were performed again to study the effect of annealing on the gamma-irradiated devices. Annealing of gamma-irradiated transistors shows that partial recovery of device performance is possible at this temperature. DC current-voltage measurements were also conducted on the transistors to assess the impact of gamma-irradiation and annealing on transfer, gate and drain characteristics.

  16. Biogeochemical processes controlling the mobility of major ions and trace metals in aquitard sediments beneath an oil sand tailing pond: Laboratory studies and reactive transport modeling

    NASA Astrophysics Data System (ADS)

    Holden, A. A.; Haque, S. E.; Mayer, K. U.; Ulrich, A. C.

    2013-08-01

    Increased production and expansion of the oil sand industry in Alberta are of great benefit to the economy, but they carry major environmental challenges. The volume of fluid fine tailings requiring storage is 840 × 106 m3 and growing, making it imperative that we better understand the fate and transport of oil sand process-affected water (OSPW) seepage from these facilities. Accordingly, the current study seeks to characterize both a) the potential for major ion and trace element release, and b) the principal biogeochemical processes involved, as tailing pond OSPW infiltrates into, and interacts with, underlying glacial till sediments prior to reaching down gradient aquifers or surface waters. Objectives were addressed through a series of aqueous and solid phase experiments, including radial diffusion cells, an isotope analysis, X-ray diffraction, and sequential extractions. The diffusion cells were also simulated in a reactive transport framework to elucidate key reaction processes. The experiments indicate that the ingress and interaction of OSPW with the glacial till sediment-pore water system will result in: a mitigation of ingressing Na (retardation), displacement and then limited precipitation of exchangeable Ca and Mg (as carbonates), sulfate reduction and subsequent precipitation of the produced sulfides, as well as biodegradation of organic carbon. High concentrations of ingressing Cl (~ 375 mg L- 1) and Na (~ 575 mg L- 1) (even though the latter is delayed, or retarded) are expected to migrate through the till and into the underlying sand channel. Trace element mobility was influenced by ion exchange, oxidation-reduction, and mineral phase reactions including reductive dissolution of metal oxyhydroxides — in accordance with previous observations within sandy aquifer settings. Furthermore, although several trace elements showed the potential for release (Al, B, Ba, Cd, Mn, Pb, Si, Sr), large-scale mobilization is not supported. Thus, the present

  17. Biogeochemical processes controlling the mobility of major ions and trace metals in aquitard sediments beneath an oil sand tailing pond: laboratory studies and reactive transport modeling.

    PubMed

    Holden, A A; Haque, S E; Mayer, K U; Ulrich, A C

    2013-08-01

    Increased production and expansion of the oil sand industry in Alberta are of great benefit to the economy, but they carry major environmental challenges. The volume of fluid fine tailings requiring storage is 840×10(6) m(3) and growing, making it imperative that we better understand the fate and transport of oil sand process-affected water (OSPW) seepage from these facilities. Accordingly, the current study seeks to characterize both a) the potential for major ion and trace element release, and b) the principal biogeochemical processes involved, as tailing pond OSPW infiltrates into, and interacts with, underlying glacial till sediments prior to reaching down gradient aquifers or surface waters. Objectives were addressed through a series of aqueous and solid phase experiments, including radial diffusion cells, an isotope analysis, X-ray diffraction, and sequential extractions. The diffusion cells were also simulated in a reactive transport framework to elucidate key reaction processes. The experiments indicate that the ingress and interaction of OSPW with the glacial till sediment-pore water system will result in: a mitigation of ingressing Na (retardation), displacement and then limited precipitation of exchangeable Ca and Mg (as carbonates), sulfate reduction and subsequent precipitation of the produced sulfides, as well as biodegradation of organic carbon. High concentrations of ingressing Cl (~375 mg L(-1)) and Na (~575 mg L(-1)) (even though the latter is delayed, or retarded) are expected to migrate through the till and into the underlying sand channel. Trace element mobility was influenced by ion exchange, oxidation-reduction, and mineral phase reactions including reductive dissolution of metal oxyhydroxides - in accordance with previous observations within sandy aquifer settings. Furthermore, although several trace elements showed the potential for release (Al, B, Ba, Cd, Mn, Pb, Si, Sr), large-scale mobilization is not supported. Thus, the present

  18. Mobile Virtual Private Networking

    NASA Astrophysics Data System (ADS)

    Pulkkis, Göran; Grahn, Kaj; Mårtens, Mathias; Mattsson, Jonny

    Mobile Virtual Private Networking (VPN) solutions based on the Internet Security Protocol (IPSec), Transport Layer Security/Secure Socket Layer (SSL/TLS), Secure Shell (SSH), 3G/GPRS cellular networks, Mobile IP, and the presently experimental Host Identity Protocol (HIP) are described, compared and evaluated. Mobile VPN solutions based on HIP are recommended for future networking because of superior processing efficiency and network capacity demand features. Mobile VPN implementation issues associated with the IP protocol versions IPv4 and IPv6 are also evaluated. Mobile VPN implementation experiences are presented and discussed.

  19. Residential mobility microsimulation models

    NASA Astrophysics Data System (ADS)

    Wang, Yifei; Wu, Lun

    2010-09-01

    Residential mobility refers to the spatial movement of individuals and households between dwellings within an urban area. This considerable amount of intra-urban movement affects the urban structure and has significant repercussions for urban transportation. In order to understand and project related impacts, a considerable number of residential mobility models has been developed and used in the regional planning process. Within this context, the history and state-of-art residential mobility models are discussed and indicated. Meanwhile, a residential mobility Microsimulation model, called URM-Microsim (Urban Residential Mobility Microsimulation), is introduced and discussed.

  20. Coupling Sorption to Soil Weathering During Reactive Transport: Impacts of Mineral Transformation and Sorbate Aging on Contaminant Speciation and Mobility

    SciTech Connect

    Chorover, Jon; Mueller, Karl T.; O'Day, Peggy; Serne, R. Jeff; Um, Wooyong; Steefel, Carl

    2006-06-01

    Our work is aimed at developing a predictive-mechanistic understanding of the coupling between mineral weathering from caustic waste release and contaminant (Cs, Sr, I) fate and transport in waste-impacted sediments across space, time and geochemical gradients that encompass the process-level heterogeneity observed at the Hanford DOE site. Our specific objectives are: (1) to assess the molecular-scale mechanisms responsible for time-dependent sequestration of contaminants (Cs, Sr and I) during penetration of waste-induced weathering fronts through sedimentary media; (2) to determine the rate and extent of contaminant release from the sorbed state; (3) to develop a reactive transport model based on molecular mechanisms and macroscopic flow experiments (from (1) and (2)) that accurately simulates adsorption, aging, and desorption at the bench-scale, and that can be applied to--and validated at--field sites such as Hanford.

  1. The Peñalosa Principle of Transportation Democracy: Lessons from Bogotá on the Morality of Urban Mobility.

    PubMed

    Epting, Shane

    2016-12-01

    The mayor of Bogotá, Enrique Peñalosa strives to deliver transit services that promote social equity through bicycle lanes, improved sidewalks, and a world-famous Bus Rapid Transit (BRT) system, "TransMilenio." Through examining the principles that guide his planning, we can flesh out a starting point for socially just transit systems. While such measures can alleviate several harms that transit systems cause, they rest on an incomplete foundation due to their top-down nature. To amend this situation, the author argues for a restorative justice approach to transportation democracy, using examples from Peñalosa's mayoral tenure. In turn, lessons from Bogotá's transportation history reveal how to develop transit systems that strongly favor justice.

  2. Description of bipolar charge transport in polyethylene using a fluid model with a constant mobility: model prediction

    NASA Astrophysics Data System (ADS)

    LeRoy, S.; Segur, P.; Teyssedre, G.; Laurent, C.

    2004-01-01

    We present a conduction model aimed at describing bipolar transport and space charge phenomena in low density polyethylene under dc stress. In the first part we recall the basic requirements for the description of charge transport and charge storage in disordered media with emphasis on the case of polyethylene. A quick review of available conduction models is presented and our approach is compared with these models. Then, the bases of the model are described and related assumptions are discussed. Finally, results on external current, trapped and free space charge distributions, field distribution and recombination rate are presented and discussed, considering a constant dc voltage, a step-increase of the voltage, and a polarization-depolarization protocol for the applied voltage. It is shown that the model is able to describe the general features reported for external current, electroluminescence and charge distribution in polyethylene.

  3. A transportable high-resolution gamma-ray spectrometer and analysis system applicable to mobile, autonomous or unattended applications

    SciTech Connect

    Buckley, W.M.; Neufeld, K.W.

    1995-07-01

    The Safeguards Technology Program at the Lawrence Livermore National Laboratory is developing systems based on a compact electro-mechanically cooled high-purity germanium (HPGe) detector. This detector system broadens the practicality of performing high- resolution gamma-ray spectrometry in the field. Utilizing portable computers, multi-channel analyzers and software these systems greatly improve the ease of performing mobile high-resolution gamma-ray spectrometry. Using industrial computers, we can construct systems that will run autonomously for extended periods of time without operator input or maintenance. These systems can start or make decisions based on sensor inputs rather than operator interactions. Such systems can provide greater capability for wider domain of safeguards, treaty verification application, and other unattended, autonomous or in-situ applications.

  4. Impact of carboxymethyl cellulose coating on iron sulphide nanoparticles stability, transport, and mobilization potential of trace metals present in soils and sediment.

    PubMed

    Van Koetsem, Frederik; Van Havere, Lynn; Du Laing, Gijs

    2016-03-01

    The stability and transport behaviour of carboxymethyl cellulose (CMC) stabilized iron sulphide (FeS) engineered nanoparticles (ENPs) as well as their concurrent scavenging and mobilization of trace metal contaminants from field-contaminated soils and sediment was studied through a series of batch and column experiments. The synthesized CMC-FeS ENPs were shown to have a hydrodynamic diameter of 154.5 ± 5.8 nm and remained stable in suspension for a prolonged period of time (several weeks) when kept under anaerobic conditions. In the absence of CMC, much larger FeS particles were formed, which quickly aggregated and precipitated within minutes. Batch experiments indicated that the CMC-FeS ENPs have a high affinity for metal contaminants (e.g., Cd, Cr, Cu, Hg, Ni, Pb, and Zn), as high amounts of these trace metals could be retrieved in the aqueous phase after treatment of the soils with the nanoparticles (i.e., up to 29 times more compared to the water-leachable metal contents). Furthermore, batch retention of the nanoparticles by the solid soil phase was low (<37%), also suggesting a high stability and potential mobility. Nanoparticle treatment of the soils also affected the CaCl2-, TCLP-, and SPLP-leachability of trace metals, although no clear trend could be observed and metal leaching appeared to depend on the specific element under consideration, the type of extraction liquid, as well as on soil properties. Column breakthrough tests demonstrated that the CMC-FeS ENPs were highly mobile in the tested soil, even without the use of an external pressure (i.e., just via gravitational percolation). Maximal breakthrough of the nanoparticles was observed after approximately 10 or 16 pore volumes (PVs) for 83.3 or 500 mg L(-1) CMC-FeS ENPs, respectively, and only about 7% of the nanoparticles were retained by the soil after 22.7 PVs. Simultaneous elution of trace elements showed that up to 19, 8.7, or 11% of the respective Cd, Pb, or Zn content originally present

  5. Coupling Sorption to Soil Weathering During Reactive Transport: Impacts of Mineral Transformation and Sorbent Aging on Contaminant Speciation and Mobility

    SciTech Connect

    Chorover, J.; Mueller, K. T.; O'Day, P. A.; Serne, R. J.; Steefel, C. I.

    2009-10-30

    This project aimed for a predictive-mechanistic understanding of the coupling between mineral weathering and contaminant (Cs, Sr, I) transport/fate in caustic waste-impacted sediments. Based on our prior studies of model clay mineral systems, we postulated that contaminant uptake to Hanford sediments would reflect concurrent adsorption and co-precipitation effects. Our specific objectives were: (1) to assess the molecular-scale mechanisms responsible for time-dependent sequestration of contaminants (Cs, Sr and I) during penetration of waste-induced weathering fronts; (2) to determine the rate and extent of contaminant release from the sorbed state; (3) to develop a reactive transport model based on molecular mechanisms and macroscopic flow experiments [(1) and (2)] that simulates adsorption, aging, and desorption dynamics. Progress toward achieving each of these objectives is discussed below. We observed unique molecular mechanisms for sequestration of Sr, Cs and I during native silicate weathering in caustic waste. Product solids, which included poorly crystalline aluminosilicates and well-crystallized zeolites and feldspathoids, accumulate contaminant species during crystal growth.

  6. Transport mechanism of reverse surface leakage current in AlGaN/GaN high-electron mobility transistor with SiN passivation

    NASA Astrophysics Data System (ADS)

    Zheng, Xue-Feng; Fan, Shuang; Chen, Yong-He; Kang, Di; Zhang, Jian-Kun; Wang, Chong; Mo, Jiang-Hui; Li, Liang; Ma, Xiao-Hua; Zhang, Jin-Cheng; Hao, Yue

    2015-02-01

    The transport mechanism of reverse surface leakage current in the AlGaN/GaN high-electron mobility transistor (HEMT) becomes one of the most important reliability issues with the downscaling of feature size. In this paper, the research results show that the reverse surface leakage current in AlGaN/GaN HEMT with SiN passivation increases with the enhancement of temperature in the range from 298 K to 423 K. Three possible transport mechanisms are proposed and examined to explain the generation of reverse surface leakage current. By comparing the experimental data with the numerical transport models, it is found that neither Fowler-Nordheim tunneling nor Frenkel-Poole emission can describe the transport of reverse surface leakage current. However, good agreement is found between the experimental data and the two-dimensional variable range hopping (2D-VRH) model. Therefore, it is concluded that the reverse surface leakage current is dominated by the electron hopping through the surface states at the barrier layer. Moreover, the activation energy of surface leakage current is extracted, which is around 0.083 eV. Finally, the SiN passivated HEMT with a high Al composition and a thin AlGaN barrier layer is also studied. It is observed that 2D-VRH still dominates the reverse surface leakage current and the activation energy is around 0.10 eV, which demonstrates that the alteration of the AlGaN barrier layer does not affect the transport mechanism of reverse surface leakage current in this paper. Project supported by the National Natural Science Foundation of China (Grant Nos. 61334002, 61106106, and 61474091), the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory, China (Grant No. ZHD201206), the New Experiment Development Funds for Xidian University, China (Grant No. SY1213), the 111 Project, China (Grant No. B12026), the Scientific Research Foundation for the Returned Overseas Chinese Scholars

  7. Walk Score, Transportation Mode Choice, and Walking Among French Adults: A GPS, Accelerometer, and Mobility Survey Study

    PubMed Central

    Duncan, Dustin T.; Méline, Julie; Kestens, Yan; Day, Kristen; Elbel, Brian; Trasande, Leonardo; Chaix, Basile

    2016-01-01

    Background: Few studies have used GPS data to analyze the relationship between Walk Score, transportation choice and walking. Additionally, the influence of Walk Score is understudied using trips rather than individuals as statistical units. The purpose of this study is to examine associations at the trip level between Walk Score, transportation mode choice, and walking among Paris adults who were tracked with GPS receivers and accelerometers in the RECORD GPS Study. Methods: In the RECORD GPS Study, 227 participants were tracked during seven days with GPS receivers and accelerometers. Participants were also surveyed with a GPS-based web mapping application on their activities and transportation modes for all trips (6969 trips). Walk Score, which calculates neighborhood walkability, was assessed for each origin and destination of every trip. Multilevel logistic and linear regression analyses were conducted to estimate associations between Walk Score and walking in the trip or accelerometry-assessed number of steps for each trip, after adjustment for individual/neighborhood characteristics. Results: The mean overall Walk Scores for trip origins were 87.1 (SD = 14.4) and for trip destinations 87.1 (SD = 14.5). In adjusted trip-level associations between Walk Score and walking only in the trip, we found that a walkable neighborhood in the trip origin and trip destination was associated with increased odds of walking in the trip assessed in the survey. The odds of only walking in the trip were 3.48 (95% CI: 2.73 to 4.44) times higher when the Walk Score for the trip origin was “Walker’s Paradise” compared to less walkable neighborhoods (Very/Car-Dependent or Somewhat Walkable), with an identical independent effect of trip destination Walk Score on walking. The number of steps per 10 min (as assessed with accelerometry) was cumulatively higher for trips both originating and ending in walkable neighborhoods (i.e., “Very Walkable”). Conclusions: Walkable

  8. Mobility and Transportation Analysis in Support of the Light Attack Battalion (LAB) Study. Volume 2. Supporting Data.

    DTIC Science & Technology

    1983-05-01

    PROVING GROU. C R DIETZ ET AL- UNCLASSIFIED MAY 83 AMSAA TR-374-YOL-2 F/G 15/5 N L. 1j.= 15 *.," 111CA 1.0.0I 11111 ~ ~ 12.2 1 1 1111"-- MICROCOPY...Transportability Analysis in Support TcnclRpr of the Light At’tack Battalion (1A1 Study _____________ ~/ 6. PERFORMING ORG. REPORT NUMBER R . Dietz, A. Dorney, J...it... 00 00 L. CoY wd w03 Ino .4 4 w I d w0 w zC 0 4d � AlCn 00 wS U.U w CL0 0 02 00 r 08 U Iw 0id I - --~~~~ -7’---.---~-- ; 00 wV zo 00 w C. 0 z

  9. Fission-fragment attachment to aerosols and their transport through capillary tubes

    SciTech Connect

    Novick, V.J.; Alvarez, J.L.; Greenwood, R.C.

    1981-01-01

    The transport of radioactive aerosols was studied using equipment, collectively called the Helium jet, that has been constructed to provide basic nuclear physics data on fission product nuclides. The transport of the fission products in the system depends on their attachment to aerosol particles. The system consists of 1) a tube furnace which generates aerosols by the sublimation or evaporation of source material, 2) a helium stream used to transport the aerosols, 3) a 25 m settling tube to eliminate the larger aerosols and smaller aerosols that would deposit in the capillary, 4) a Californium-252 self-fissioning source of fission product nuclides, and 5) a small capillary to carry the radioactive aerosols from the hot cell to the laboratory. Different source materials were aerosolized but NaCl is generally used because it yielded the highest transport efficiencies through the capillary. Particle size measurments were made with NaCl aerosols by using a cascade impactor, an optical light scattering device, and the capillary itself as a diffusion battery by performing radiation measurements and/or electrical conductivity measurements. Both radioactive and nonradioactive aerosols were measured in order to investigate the possibility of a preferential size range for fission product attachment. The measured size distributions were then used to calculate attachment coefficients and finally an attachment time.

  10. Monitoring of event based mobilization of hydrophobic pollutants in rivers: Calibration of turbidity as a proxy for particle facilitated transport

    NASA Astrophysics Data System (ADS)

    Rügner, Hermann; Schwientek, Marc; Grathwohl, Peter

    2014-05-01

    Transport of many pollutants in rivers is coupled to transport of suspended particles which is typically enhanced during events such as floods, snow melts etc. As the amount of total suspended solids (TSS) in rivers can be monitored by turbidity measurements this may be used as a proxy for the total concentration of particle associated pollutants in rivers such as polycyclic aromatic hydrocarbons (PAHs), PCBs, etc. and several heavy metals. On-line turbidity measurements (e.g. by optical backscattering sensors) then allow for an assessment of particle and pollutant flux dynamics. In this study, pronounced flood and thus turbidity events were sampled at high temporal resolution in three contrasting catchments in Southwest Germany (Rivers Ammer, Goldersbach, Steinlach) as well as in the River Neckar. Samples were analyzed for turbidity, the total amount of PAH and total suspended solids (TSS) in water. Additionally, the grain size distributions of suspended solids were determined. Discharge and turbidity were measured on-line at gauging stations in three of the catchments. Results showed that turbidity and TSS were linearly correlated over an extended turbidity range up to 2000 NTU for the flood samples (i.e. independent on grain size). This also holds for total PAH concentrations which can be reasonably well predicted based on the turbidity measurements and TSS versus PAH relationships - even for very high turbidity or TSS values (> 2000 NTU or mg l-1, respectively). From these linear regressions concentrations of PAHs on suspended particles were obtained which varied by catchment. The values comprise a robust measure of the average sediment quality in a river network and may be correlated to the degree of urbanization represented by the number of inhabitants per total flux of suspended particles. Based on long-term on-line turbidity measurements mass flow rates of particle bound pollutants over time could be calculated. Results showed that by far the largest amount

  11. Process-based reactive transport model to quantify arsenic mobility during aquifer storage and recovery of potable water.

    PubMed

    Wallis, Ilka; Prommer, Henning; Pichler, Thomas; Post, Vincent; Norton, Stuart B; Annable, Michael D; Simmons, Craig T

    2011-08-15

    Aquifer storage and recovery (ASR) is an aquifer recharge technique in which water is injected in an aquifer during periods of surplus and withdrawn from the same well during periods of deficit. It is a critical component of the long-term water supply plan in various regions, including Florida, USA. Here, the viability of ASR as a safe and cost-effective water resource is currently being tested at a number of sites due to elevated arsenic concentrations detected during groundwater recovery. In this study, we developed a process-based reactive transport model of the coupled physical and geochemical mechanisms controlling the fate of arsenic during ASR. We analyzed multicycle hydrochemical data from a well-documented affected southwest Floridan site and evaluated a conceptual/numerical model in which (i) arsenic is initially released during pyrite oxidation triggered by the injection of oxygenated water (ii) then largely complexes to neo-formed hydrous ferric oxides before (iii) being remobilized during recovery as a result of both dissolution of hydrous ferric oxides and displacement from sorption sites by competing anions.

  12. Efforts to Reduce International Space Station Crew Maintenance Time in the Management of the Extravehicular Mobility Unit Transport Loop Water Quality

    NASA Technical Reports Server (NTRS)

    Etter,David; Rector, Tony; Boyle, robert; Zande, Chris Vande

    2012-01-01

    The EMU (Extravehicular Mobility Unit) contains a semi-closed-loop re-circulating water circuit (Transport Loop) to absorb heat into a LCVG (Liquid Coolant and Ventilation Garment) worn by the astronaut. A second, single-pass water circuit (Feed-water Loop) provides water to a cooling device (Sublimator) containing porous plates, and that water sublimates through the porous plates to space vacuum. The cooling effect from the sublimation of this water translates to a cooling of the LCVG water that circulates through the Sublimator. The quality of the EMU Transport Loop water is maintained through the use of a water processing kit (ALCLR - Airlock Cooling Loop Remediation) that is used to periodically clean and disinfect the water circuit. Opportunities to reduce crew time associated with ALCLR operations include a detailed review of the historical water quality data for evidence to support an extension to the implementation cycle. Furthermore, an EMU returned after 2-years of use on the ISS (International Space Station) is being used as a test bed to evaluate the results of extended and repeated ALCLR implementation cycles. Finally, design, use and on-orbit location enhancements to the ALCLR kit components are being considered to allow the implementation cycle to occur in parallel with other EMU maintenance and check-out activities, and to extend the life of the ALCLR kit components. These efforts are undertaken to reduce the crew-time and logistics burdens for the EMU, while ensuring the long-term health of the EMU water circuits for a post- Shuttle 6-year service life.

  13. Monitoring of event-based mobilization of hydrophobic pollutants in rivers: calibration of turbidity as a proxy for particle facilitated transport in field and laboratory.

    PubMed

    Rügner, Hermann; Schwientek, Marc; Egner, Marius; Grathwohl, Peter

    2014-08-15

    Transport of many pollutants in rivers is coupled to mobilization of suspended particles which typically occurs during floods. Since the amount of total suspended solids (TSS) in rivers can be monitored by turbidity measurements this may be used as a proxy for the total concentration of particle associated pollutants such as PAHs, PCBs, etc. and several heavy metals. Online turbidity measurements (e.g. by optical backscattering sensors) would then also allow for an assessment of particle and pollutant flux dynamics if once calibrated against TSS and total pollutant concentrations for a given catchment. In this study, distinct flood and thus turbidity events were sampled at high temporal resolution in three contrasting sub-catchments of the River Neckar in Southwest Germany (Ammer, Goldersbach, Steinlach) as well as in the River Neckar itself and investigated for the total amount of PAHs and TSS in water; turbidity (NTU) and grain size distributions of suspended solids were determined as well. Laboratory experiments were performed with natural river bed sediments from different locations (Ammer) to investigate PAH concentrations, TSS and turbidity during sedimentation of suspended particles under controlled conditions (yielding smaller and smaller suspended particles and TSS with time). Laboratory and field results agreed very well and showed that turbidity and TSS were linearly correlated over an extended turbidity range up to 2000 NTU for the field samples and up to 8000 NTU in lab experiments. This also holds for total PAH concentrations which can be reasonably well predicted based on turbidity measurements and TSS vs. PAHs relationships - even for high turbidity values observed during flood events (>2000 NTU). Total PAH concentrations on suspended solids were independent of grain size of suspended particles. This implies that for the rivers investigated the sorption capacity of particles did not change significantly during the observed events.

  14. Mobile Learning Using Mobile Phones

    ERIC Educational Resources Information Center

    Vicente, Paula

    2013-01-01

    The participation in mobile learning programs is conditioned by having/using mobile communication technology. Those who do not have or use such technology cannot participate in mobile learning programs. This study evaluates who are the most likely participants of mobile learning programs by examining the demographic profile and mobile phone usage…

  15. Skylab mobile laboratory

    NASA Technical Reports Server (NTRS)

    Primeaux, G. R.; Larue, M. A.

    1975-01-01

    The Skylab mobile laboratory was designed to provide the capability to obtain necessary data on the Skylab crewmen 30 days before lift-off, within 1 hour after recovery, and until preflight physiological baselines were reattained. The mobile laboratory complex consisted of six laboratories that supported cardiovascular, metabolic, nutrition and endocrinology, operational medicine, blood, and microbiology experiments; a utility package; and two shipping containers. The objectives and equipment requirements of the Skylab mobile laboratory and the data acquisition systems are discussed along with processes such as permanently mounting equipment in the individual laboratories and methods of testing and transporting the units. The operational performance, in terms of amounts of data collected, and the concept of mobile laboratories for medical and scientific experiments are evaluated. The Skylab mobile laboratory succeeded in facilitating the data collection and sample preservation associated with the three Skylab manned flights.

  16. FINAL REPORT: Coupling Sorption to Soil Weathering During Reactive Transport: Impacts of Mineral Transformation and Sorbent Aging on Contaminant Speciation and Mobility

    SciTech Connect

    O'Day, Peggy A.; Chorover, Jon; Mueller, Karl; Steefel, Carl; Serne, R. Jeff

    2009-03-21

    The goal of our project is a predictive-mechanistic understanding of the coupling between mineral weathering and contaminant (Cs, Sr, I) fate in caustic waste-impacted sediments at the Hanford Site. Through bench-scale experiments, we have identified geochemical transformations that alter the mobility of priority pollutants (Cs, Sr, I) in subsurface environments characteristic of high-level radioactive waste (HLRW)-impacted DoE sites. Our studies are designed to model the unique chemistry of this subsurface contamination, to quantify rates of contaminant uptake and release, and to identify molecular mechanisms of time-dependent, irreversible sequestration of contaminants into the solid phase. Our approach is to link quantitative macroscopic measures of contaminant mobility and partitioning to the molecular-scale mechanisms that mediate them. We have found that the molecular mechanisms themselves change with time and system composition in response to the evolving chemistry of contaminant-solution-mineral interactions. Specifically, our results show that contaminant fate is closely coupled to the major silicate incongruent weathering reactions that occur when soil solids are contacted with aqueous solutions under conditions that are far from equilibrium. Neoformed precipitates - including carbonate, feldspathoid and zeolite phases, have been observed to sequester Cs and Sr under caustic waste conditions. In contrast, iodide is less effectively sequestered into the neoformed precipitates. In any case, the long-term stability of these co-precipitates must be assessed, particularly in respect to the site closure scenario wherein sediment pore water is expected to return to a “natural” pH and ionic strength fed by rainwater recharge after removal of the caustic source. Our research centers on a series of saturated and unsaturated column studies conducted on Hanford Formation sediments that had been previously reacted in batch or column systems with synthetic tank

  17. Mobile-ip Aeronautical Network Simulation Study

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Tran, Diepchi T.

    2001-01-01

    NASA is interested in applying mobile Internet protocol (mobile-ip) technologies to its space and aeronautics programs. In particular, mobile-ip will play a major role in the Advanced Aeronautic Transportation Technology (AATT), the Weather Information Communication (WINCOMM), and the Small Aircraft Transportation System (SATS) aeronautics programs. This report presents the results of a simulation study of mobile-ip for an aeronautical network. The study was performed to determine the performance of the transmission control protocol (TCP) in a mobile-ip environment and to gain an understanding of how long delays, handoffs, and noisy channels affect mobile-ip performance.

  18. 49 CFR 38.23 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Mobility aid accessibility. 38.23 Section 38.23 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 38.23 Mobility aid accessibility....

  19. Charge transport calculations by a wave-packet dynamical approach using maximally localized Wannier functions based on density functional theory: Application to high-mobility organic semiconductors

    NASA Astrophysics Data System (ADS)

    Ishii, Hiroyuki; Kobayashi, Nobuhiko; Hirose, Kenji

    2017-01-01

    We present a wave-packet dynamical approach to charge transport using maximally localized Wannier functions based on density functional theory including van der Waals interactions. We apply it to the transport properties of pentacene and rubrene single crystals and show the temperature-dependent natures from bandlike to thermally activated behaviors as a function of the magnitude of external static disorder. We compare the results with those obtained by the conventional band and hopping models and experiments.

  20. Conditions and processes affecting radionuclide transport

    USGS Publications Warehouse

    Simmons, Ardyth M.; Neymark, Leonid A.

    2012-01-01

    Understanding of unsaturated-zone transport is based on laboratory and field-scale experiments. Fractures provide advective transport pathways. Sorption and matrix diffusion may contribute to retardation of radionuclides. Conversely, sorption onto mobile colloids may enhance radionuclide transport.

  1. Fluorescence recovery after photobleaching measured by confocal microscopy as a tool for the analysis of vesicular lipid transport and plasma membrane mobility

    NASA Astrophysics Data System (ADS)

    Schmitz, Gerd; Goetz, Alexandra; Orso, Evelyn; Rothe, Gregor

    1998-04-01

    The vesicular transport of lipids from the endoplasmic reticulum via the Golgi apparatus affects the composition of the plasma membrane. The purpose of our study was to develop an in vitro test system for characterization of vesicular lipid transport kinetics by using confocal microscopy and fluorescence recovery after photobleaching (FRAP). Fibroblasts from two patients homozygous for the hypercatabolic HDL deficiency syndrome Tangier disease and 4 control subjects were pulsed with the C6-NBD-ceramide for 30 minutes. Chase incubation at room temperature resulted in the metabolic accumulation of fluorescent C6-NBD-sphingolyelin and C6-NBD-glycosylceramides in the medial- and trans-Golgi region. Cells were analyzed with an inverted Leica TCS microscope. Calibration was performed through the analysis of diffusion of 50 nm microparticles embedded in media of different viscosity. An acousto optical tunable filter (AOTF) was used for the selective bleaching of the medial- and trans- Golgi region followed by analysis of the fluorescence recovery for 4 minutes. Post-bleach fluorescence recovery through the trans-Golgi-oriented transport of NBD-sphingomyelin was calculated from 2-dimensional scans. Tangier fibroblasts displayed a retarded recovery of fluorescence in the trans- Golgi region. This suggests that the vesicular transport of sphingomyelin and cholesterol is disturbed in Tangier disease confirming data from our laboratory generated with radiometabolites on whole cells. Our data suggest that FRAP analysis allows a sensitive kinetic and spatially resolved analysis of disturbances of vesicular lipid transport.

  2. Application of Mobile-ip to Space and Aeronautical Networks

    NASA Technical Reports Server (NTRS)

    Leung, Kent; Shell, Dan; Ivancic, William D.; Stewart, David H.; Bell, Terry L.; Kachmar, Brian A.

    2001-01-01

    The National Aeronautics and Space Administration (NASA) is interested in applying mobile Internet protocol (mobile-ip) technologies to its space and aeronautics programs. In particular, mobile-ip will play a major role in the Advanced Aeronautic Transportation Technology (AAT-F), the Weather Information Communication (WINCOMM), and the Small Aircraft Transportation System (SATS) aeronautics programs. This paper describes mobile-ip and mobile routers--in particular, the features, capabilities, and initial performance of the mobile router are presented. The application of mobile-router technology to NASA's space and aeronautics programs is also discussed.

  3. FINAL REPORT: Coupling Sorption to Soil Weathering During Reactive Transport: Impacts of Mineral Transformation and Sorbent Aging on Contaminant Speciation and Mobility

    SciTech Connect

    Mueller, Karl T; Chorover, John C; ODay, Peggy A; Um, Wooyong; Steefel, Carl I

    2009-10-05

    This project aimed for a predictive-mechanistic understanding of the coupling between mineral weathering and contaminant (Cs, Sr, I) transport/fate in caustic waste-impacted sediments. Based on our prior studies of model clay mineral systems, we postulated that contaminant uptake to Hanford sediments would reflect concurrent adsorption and co-precipitation effects. Our specific objectives were: (1) to assess the molecular-scale mechanisms responsible for time-dependent sequestration of contaminants (Cs, Sr and I) during penetration of waste-induced weathering fronts; (2) to determine the rate and extent of contaminant release from the sorbed state; (3) to develop a reactive transport model based on molecular mechanisms and macroscopic flow experiments [(1) and (2)] that simulates adsorption, aging, and desorption dynamics. Progress toward achieving each of these objectives is discussed in this Final Report.

  4. Mobile systems capability plan

    SciTech Connect

    1996-09-01

    This plan was prepared to initiate contracting for and deployment of these mobile system services. 102,000 cubic meters of retrievable, contact-handled TRU waste are stored at many sites around the country. Also, an estimated 38,000 cubic meters of TRU waste will be generated in the course of waste inventory workoff and continuing DOE operations. All the defense TRU waste is destined for disposal in WIPP near Carlsbad NM. To ship TRU waste there, sites must first certify that the waste meets WIPP waste acceptance criteria. The waste must be characterized, and if not acceptable, subjected to additional processing, including repackaging. Most sites plan to use existing fixed facilities or open new ones between FY1997-2006 to perform these functions; small-quantity sites lack this capability. An alternative to fixed facilities is the use of mobile systems mounted in trailers or skids, and transported to sites. Mobile systems will be used for all characterization and certification at small sites; large sites can also use them. The Carlsbad Area Office plans to pursue a strategy of privatization of mobile system services, since this offers a number of advantages. To indicate the possible magnitude of the costs of deploying mobile systems, preliminary estimates of equipment, maintenance, and operating costs over a 10-year period were prepared and options for purchase, lease, and privatization through fixed-price contracts considered.

  5. Robotic transportation.

    PubMed

    Lob, W S

    1990-09-01

    Mobile robots perform fetch-and-carry tasks autonomously. An intelligent, sensor-equipped mobile robot does not require dedicated pathways or extensive facility modification. In the hospital, mobile robots can be used to carry specimens, pharmaceuticals, meals, etc. between supply centers, patient areas, and laboratories. The HelpMate (Transitions Research Corp.) mobile robot was developed specifically for hospital environments. To reach a desired destination, Help-Mate navigates with an on-board computer that continuously polls a suite of sensors, matches the sensor data against a pre-programmed map of the environment, and issues drive commands and path corrections. A sender operates the robot with a user-friendly menu that prompts for payload insertion and desired destination(s). Upon arrival at its selected destination, the robot prompts the recipient for a security code or physical key and awaits acknowledgement of payload removal. In the future, the integration of HelpMate with robot manipulators, test equipment, and central institutional information systems will open new applications in more localized areas and should help overcome difficulties in filling transport staff positions.

  6. Manned Mars mission surface transportation elements

    NASA Technical Reports Server (NTRS)

    Mcdaniel, S. Gregg; Mulqueen, Jack

    1986-01-01

    The necessity and advantage of surface transportation was well demonstrated by the Apollo 15, 16, and 17 missions. Baseline surface transportation elements for further studies are Lunar Rover, Elastic Loop Mobility System, Mobile Laboratory, Airplane, and Rocket Powered Flying Vehicles. These types of surface transportation are discussed. Starting points for further in-depth studies are identified.

  7. High electron mobility in bathophenanthroline

    NASA Astrophysics Data System (ADS)

    Naka, Shigeki; Okada, Hiroyuki; Onnagawa, Hiroyoshi; Tsutsui, Tetsuo

    2000-01-01

    We have measured electron mobility in vacuum-deposited films of 4,7-diphenyl-1,10phenanthroline (bathophenanthroline, or BPhen) using a time-of-flight technique. Electron transport was highly dispersive for BPhen with a dispersion parameter of a value 0.30. The electron mobility in excess of 10-4 cm2/V s has been observed at electric fields of the order of 105 V/cm with weakly dependent on the electric field. The characteristic energy of the distribution is obtained a value 0.09 eV. It is directly confirmed that the BPhen has superior electron-transport capability.

  8. Cadmium (II) and lead (II) transport in a polymer inclusion membrane using tributyl phosphate as mobile carrier and CuFeO(2) as a polarized photo electrode.

    PubMed

    Arous, Omar; Amara, Mourad; Trari, Mohamed; Bouguelia, Aissa; Kerdjoudj, Hacène

    2010-08-15

    In this work, a development of polymeric inclusion membranes for the cations separation is reported. The membrane was made up of cellulose triacetate (CTA) with a tributyl phosphate (TBP) incorporated into the polymer as metal ions carrier. The transport of lead (II) and cadmium (II) ions in two membrane systems polymer inclusion membrane (PIM), PIM coupled with photo-chemical electrode using TBP as carrier and 2-nitro phenyl octyl ether (NPOE) or tris ethylhexyl phosphate (TEHP) as plasticizer have been investigated. The membranes: polymer+plasticizer+carrier were synthesized and characterized by FTIR, X-ray diffraction and scanning electron microscopy (SEM). Transports of lead and cadmium have been studied using these systems and the results were compared to commercial cation exchange membrane (CRA). The obtained results showed that for Pb(2+) ion, the concentrations of the strip phase increases using synthesized membranes. The conduction band of the delafossite CuFeO(2) (-1.25 V(SCE)) yields a thermodynamically M(2+) (=Pb(2+), Cd(2+)) photo electrodeposition and speeds up the diffusion process. In all the cases, the potential of the electrode M/M(2+) in the feed compartment increases until a maximum value, reached at approximately 100 min above which it undergoes a diminution.

  9. Self-deformation in a direct current driven helium jet micro discharge

    SciTech Connect

    Xu, S. F.; Zhong, X. X.

    2016-01-15

    We report on the experimental observation of three dimensional self-deformation in an atmospheric micro discharge of the helium microjet through a tube into the ambient air upon a water electrode. The geometry of the discharge system is axial symmetric. While decreasing the discharge current, three dimensional collective motion of plasma filaments is directly observed. The three dimensional configuration of the discharge self changed from an axial symmetrical horn to a rectangular horn when the water acts as a cathode.

  10. Luminescence studies of trace gases through metastable transfer in cold helium jets

    NASA Astrophysics Data System (ADS)

    Wilde, Scott Colton

    Among the elements, Helium has the largest steps among its internal energy structure that can keep for long periods of time, hence the metastable helium moniker. It is referred to as a "nano-grenade" in some circles because of how much energy it can deliver to a space roughly the size of an atom. This work demonstrates a method to create metastable helium abundantly and it is used to excite trace amounts of oxygen to the point where the signal received from the oxygen was larger than the signal received from the helium in a cold atomized jet. Further cooling of the jet and turbulence added by a liquid helium surface worked to increase the oxygen signal and decrease the helium signal. This work investigates the possibility of forming a strong metastable helium source from a flowing helium gas jet excited by passing through ring electrodes introduced into a cryogenic environment using evaporated helium as a buffer gas. Prior study of luminescence from trace gases at cold helium temperatures is virtually absent and so it is the motivation for this work to blaze the trail in this subject. The absence of ionic oxygen spectral lines from the transfer of energy that was well over the first ionization potential of oxygen made for a deeper understanding of collision dynamics with multiple collision partners. This opened the possibility of using the high energy states of oxygen after metastable transfer as a lasing transition previously unavailable and a preliminary analysis suggested that the threshold for lasing action should be easily overcome if feedback were introduced by an optical cavity. To better understand the thermodynamics of the jet it was proposed to use diatomic nitrogen as an in situ thermometer, investigating whether the rotational degrees of freedom of the nitrogen molecule were in thermal equilibrium with the surrounding environment. If the gas was truly in thermodynamic equilibrium then the temperature given by the method of using collisions of a buffer gas and the rotational temperature determined spectroscopically should be in agreement. It was found that metastable transfer from helium in the jet provides enough energy to create a population of hot molecules of nitrogen that never reach thermal equilibrium with the buffer gas which is almost entirely made up of ground state helium atoms. This effect can be corrected for by adding some significant changes to the optical setup but are not outside the realm of possibility as they have been designed and built for other experiments. Therefore the rotational spectra of nitrogen could be used as an in situ thermometer at cryogenic temperatures with metastable helium present provided the hot molecule contribution due to collisions of the second kind of nitrogen and helium is measured and removed.

  11. Flow instabilities in non-uniformly heated helium jet arrays used for divertor PFCs

    SciTech Connect

    Youchison, Dennis L.

    2015-07-30

    In this study, due to a lack of prototypical experimental data, little is known about the off-normal behavior of recently proposed divertor jet cooling concepts. This article describes a computational fluid dynamics (CFD) study on two jet array designs to investigate their susceptibility to parallel flow instabilities induced by non-uniform heating and large increases in the helium outlet temperature. The study compared a single 25-jet helium-cooled modular divertor (HEMJ) thimble and a micro-jet array with 116 jets. Both have pure tungsten armor and a total mass flow rate of 10 g/s at a 600 °C inlet temperature. We investigated flow perturbations caused by a 30 MW/m2 off-normal heat flux applied over a 25 mm2 area in addition to the nominal 5 MW/m2 applied over a 75 mm2 portion of the face. The micro-jet array exhibited lower temperatures and a more uniform surface temperature distribution than the HEMJ thimble. We also investigated the response of a manifolded nine-finger HEMJ assembly using the nominal heat flux and a 274 mm2 heated area. For the 30 MW/m2 case, the micro-jet array absorbed 750 W in the helium with a maximum armor surface temperature of 1280 °C and a fluid/solid interface temperature of 801 °C. The HEMJ absorbed 750 W with a maximum armor surface temperature of 1411 °C and a fluid/solid interface temperature of 844 °C. For comparison, both the single HEMJ finger and the micro-jet array used 5-mm-thick tungsten armor. The ratio of maximum to average temperature and variations in the local heat transfer coefficient were lower for the micro-jet array compared to the HEMJ device. Although high heat flux testing is required to validate the results obtained in these simulations, the results provide important guidance in jet design and manifolding to increase heat removal while providing more even temperature distribution and minimizing non-uniformity in the gas flow and thermal stresses at the armor joint.

  12. Flow instabilities in non-uniformly heated helium jet arrays used for divertor PFCs

    DOE PAGES

    Youchison, Dennis L.

    2015-07-30

    In this study, due to a lack of prototypical experimental data, little is known about the off-normal behavior of recently proposed divertor jet cooling concepts. This article describes a computational fluid dynamics (CFD) study on two jet array designs to investigate their susceptibility to parallel flow instabilities induced by non-uniform heating and large increases in the helium outlet temperature. The study compared a single 25-jet helium-cooled modular divertor (HEMJ) thimble and a micro-jet array with 116 jets. Both have pure tungsten armor and a total mass flow rate of 10 g/s at a 600 °C inlet temperature. We investigated flowmore » perturbations caused by a 30 MW/m2 off-normal heat flux applied over a 25 mm2 area in addition to the nominal 5 MW/m2 applied over a 75 mm2 portion of the face. The micro-jet array exhibited lower temperatures and a more uniform surface temperature distribution than the HEMJ thimble. We also investigated the response of a manifolded nine-finger HEMJ assembly using the nominal heat flux and a 274 mm2 heated area. For the 30 MW/m2 case, the micro-jet array absorbed 750 W in the helium with a maximum armor surface temperature of 1280 °C and a fluid/solid interface temperature of 801 °C. The HEMJ absorbed 750 W with a maximum armor surface temperature of 1411 °C and a fluid/solid interface temperature of 844 °C. For comparison, both the single HEMJ finger and the micro-jet array used 5-mm-thick tungsten armor. The ratio of maximum to average temperature and variations in the local heat transfer coefficient were lower for the micro-jet array compared to the HEMJ device. Although high heat flux testing is required to validate the results obtained in these simulations, the results provide important guidance in jet design and manifolding to increase heat removal while providing more even temperature distribution and minimizing non-uniformity in the gas flow and thermal stresses at the armor joint.« less

  13. Mobility of Source Zone Heavy Metals and Radionuclides: The Mixed Roles of Fermentative Activity on Fate and Transport of U and Cr

    SciTech Connect

    Apel, William; Peyton, Brent; Gerlach, Robin; Lee, Brady

    2006-06-01

    Predicting the potential migration of metals and radionuclides from waste pits and trenches will require understanding the effects of carbon and electron flow through these environments. Important aspects of this flow include the physiological activity of cellulolytic and non-cellulolytic fermentative microbial populations, as well as the subsequent activity of metal and radionuclide reducing bacteria. The activity of subsurface fermentative microbial populations is significantly understudied even though these organisms can affect contaminant migration by at least two mechanisms. In the first mechanism, products of the fermentation process can act as chelators for metals and radionuclides increasing their transport through underlying geological media. The second mechanism is the reduction and immobilization of metals and radionuclides since some fermentative bacteria have been shown to directly reduce metals and radionuclides, while their fermentation products can provide carbon and energy for respiratory metal reducing bacteria that can also reduce oxidized metals and radionuclides.

  14. Sustainable mobility in rural China.

    PubMed

    Dalkmann, Holger; Hutfilter, Sabine; Vogelpohl, Karin; Schnabel, Peter

    2008-04-01

    Rural areas in China suffer from various problems. The stagnating economic development and a lack of (sufficient) job opportunities and basic services, etc., lead to disadvantages for great parts of China's population. In this context, the transport sector plays a crucial role for the development of rural settlements. Although the degree of undersupply varies between villages, the situation of Chinese villages is often worsened by an insufficient developed transport sector. Regarding mobility in rural China, major constraints and therefore challenges are the difficult access to the transport infrastructure, bad road conditions and the lack of public transport systems. Improvements within the transport sector can be regarded as crucial for the economic and social development of (rural) China and should be carried out in a sustainable and holistic manner using participatory approaches. The aim should be the development of mobility strategies considering the specific needs within the field of transport, which shall have a decisive and positive impact on related sectors. This paper is based on experiences made during the 3 years lasting Sino-European research project SUCCESS (Sustainable Users Concept for China Engaging Scientific Scenario) that analyses the present and the potential future role of transport systems in selected rural areas of China. Referring to the case studies of three villages in rural China, some mobility-related projects that present a favourable impact not only on the transport sector but also on the social system and the economy shall be highlighted. Finally, based on the analysis, instruments and measures for the development of a pathway to a sustainable mobility in rural China will be outlined.

  15. Mobile healthcare.

    PubMed

    Morgan, Stephen A; Agee, Nancy Howell

    2012-01-01

    Mobile technology's presence in healthcare has exploded over the past five years. The increased use of mobile devices by all segments of the US population has driven healthcare systems, providers, and payers to accept this new form of communication and to develop strategies to implement and leverage the use of mobile healthcare (mHealth) within their organizations and practices. As healthcare systems move toward a more value-driven model of care, patient centeredness and engagement are the keys to success. Mobile healthcare will provide the medium to allow patients to participate more in their care. Financially, mHealth brings to providers the ability to improve efficiency and deliver savings to both them and the healthcare consumer. However, mHealth is not without challenges. Healthcare IT departments have been reluctant to embrace this shift in technology without fully addressing security and privacy concerns. Providers have been hesitant to adopt mHealth as a form of communication with patients because it breaks with traditional models. Our healthcare system has just started the journey toward the development of mHealth. We offer an overview of the mobile healthcare environment and our approach to solving the challenges it brings to healthcare organizations.

  16. Mobility and Orientation Instruction of Blind Persons.

    ERIC Educational Resources Information Center

    Luini, Eugene; Ryder, James

    A peripatologist taught 102 blind and partially sighted individuals of all ages mobility and orientation techniques. Volunteers assisted with transportation, followup, consultation, and direct teaching of mobility. Over a 3-year period, the number of lessons per client varied from one to 86, and the number of hours spent by the instructor in…

  17. Mobile Router Developed and Tested

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.

    2002-01-01

    The NASA Glenn Research Center, under a NASA Space Act Agreement with Cisco Systems, has been performing joint networking research to apply Internet-based technologies and protocols to space-based communications. As a result of this research, NASA performed stringent performance testing of the mobile router, including the interaction of routing and the transport-level protocol. In addition, Cisco Systems developed the mobile router for both commercial and Government markets. The code has become part of the Cisco Systems Internetworking Operating System (IOS) as of release 12.2 (4) T--which will make this capability available to the community at large. The mobile router is software code that resides in a network router and enables entire networks to roam while maintaining connectivity to the Internet. This router code is pertinent to a myriad of applications for both Government and commercial sectors, including the "wireless battlefield." NASA and the Department of Defense will utilize this technology for near-planetary observation and sensing spacecraft. It is also a key enabling technology for aviation-based information applications. Mobile routing will make it possible for information such as weather, air traffic control, voice, and video to be transmitted to aircraft using Internet-based protocols. This technology shows great promise in reducing congested airways and mitigating aviation disasters due to bad weather. The mobile router can also be incorporated into emergency vehicles (such as ambulances and life-flight aircraft) to provide real-time connectivity back to the hospital and health-care experts, enabling the timely application of emergency care. Commercial applications include entertainment services, Internet protocol (IP) telephone, and Internet connectivity for cruise ships, commercial shipping, tour buses, aircraft, and eventually cars. A mobile router, which is based on mobile IP, allows hosts (mobile nodes) to seamlessly "roam" among various IP

  18. 49 CFR 38.159 - Mobility aid accessibility.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SPECIFICATIONS FOR TRANSPORTATION VEHICLES Over-the-Road Buses and Systems § 38.159 Mobility aid accessibility... by the Department of Transportation, the bus is not required to be equipped with a...

  19. Mobility Demonstrator

    DTIC Science & Technology

    2013-08-22

    Resilient Technologies (Polaris Defense) Technology: Non- Pneumatic Tire Description: Airless Tire/wheel with honeycombed shaped polymer supporting...self-adjusting track tensioners • The biggest advancement in these systems has been pneumatic external road-arm design (external suspensions...UNCLASSIFIED: Distribution Statement A. Approved for public release. 90 Payoff:  Enabler for silent mobility, hybridization , and export power capabilities

  20. Sulfamethazine transport in agroforestry and cropland soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of veterinary antibiotic transport and persistence is critical to understanding environmental risks associated with these potential contaminants. To understand mobility of sulfamethazine (SMZ) and sorption processes involved during SMZ transport in soil, column leaching experiments were p...

  1. Mobile Customer Relationship Management and Mobile Security

    NASA Astrophysics Data System (ADS)

    Sanayei, Ali; Mirzaei, Abas

    The purpose of this study is twofold. First, in order to guarantee a coherent discussion about mobile customer relationship management (mCRM), this paper presents a conceptualization of mCRM delineating its unique characteristics because of Among the variety of mobile services, considerable attention has been devoted to mobile marketing and in particular to mobile customer relationship management services. Second, the authors discusses the security risks in mobile computing in different level(user, mobile device, wireless network,...) and finally we focus on enterprise mobile security and it's subgroups with a series of suggestion and solution for improve mobile computing security.

  2. 9 CFR 3.79 - Mobile or traveling housing facilities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Mobile or traveling housing facilities... Transportation of Nonhuman Primates 2 Facilities and Operating Standards § 3.79 Mobile or traveling housing facilities. (a) Heating, cooling, and temperature. Mobile or traveling housing facilities must...

  3. 9 CFR 3.79 - Mobile or traveling housing facilities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Mobile or traveling housing facilities... Transportation of Nonhuman Primates 2 Facilities and Operating Standards § 3.79 Mobile or traveling housing facilities. (a) Heating, cooling, and temperature. Mobile or traveling housing facilities must...

  4. 9 CFR 3.79 - Mobile or traveling housing facilities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Mobile or traveling housing facilities... Transportation of Nonhuman Primates 2 Facilities and Operating Standards § 3.79 Mobile or traveling housing facilities. (a) Heating, cooling, and temperature. Mobile or traveling housing facilities must...

  5. 9 CFR 3.79 - Mobile or traveling housing facilities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... barriers. There must be a barrier between a mobile or traveling housing facility and the public at any time... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Mobile or traveling housing facilities... Transportation of Nonhuman Primates 2 Facilities and Operating Standards § 3.79 Mobile or traveling...

  6. 49 CFR 193.2019 - Mobile and temporary LNG facilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Mobile and temporary LNG facilities. 193.2019... LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS General § 193.2019 Mobile and temporary LNG facilities. (a) Mobile and temporary LNG facilities for peakshaving application, for service...

  7. 49 CFR 193.2019 - Mobile and temporary LNG facilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Mobile and temporary LNG facilities. 193.2019... LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS General § 193.2019 Mobile and temporary LNG facilities. (a) Mobile and temporary LNG facilities for peakshaving application, for service...

  8. 49 CFR 193.2019 - Mobile and temporary LNG facilities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Mobile and temporary LNG facilities. 193.2019... LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS General § 193.2019 Mobile and temporary LNG facilities. (a) Mobile and temporary LNG facilities for peakshaving application, for service...

  9. 49 CFR 193.2019 - Mobile and temporary LNG facilities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Mobile and temporary LNG facilities. 193.2019... LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS General § 193.2019 Mobile and temporary LNG facilities. (a) Mobile and temporary LNG facilities for peakshaving application, for service...

  10. 49 CFR 193.2019 - Mobile and temporary LNG facilities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Mobile and temporary LNG facilities. 193.2019... LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS General § 193.2019 Mobile and temporary LNG facilities. (a) Mobile and temporary LNG facilities for peakshaving application, for service...

  11. Mobility Bibliography.

    DTIC Science & Technology

    1981-11-01

    Abele, G.; Walker, D.A.; Brown, J .; Brewer, M.C.; Atwood, D.M. TI - Effects of low ground pressure vehicle traffic on tundra aL Lonely, Alaska SO...resistance, bulldozing resistance. NTIS ’ DT ’ . [ Acces. J "D-4 CONTENTS Chapter I Snow vehicles or snowmobiles Chapter II Rolling resistance Chapter III...Russian Swe Swedish Eng English Jap Japanese Ger German Pol Polish Czech Czechoslovakian Nor Norwegian P reface This mobility bibliography was

  12. Going mobile

    NASA Astrophysics Data System (ADS)

    Brus, Eric

    1987-12-01

    By 1990, all metropolitan areas in the U.S. and rural areas close to major cities or towns are expected to have cellular telephone service; 22 Canadian cities also feature cellular service. To supply mobile telecommunication services to sparsely-populated rural areas, a mobile satellite service (MSS) is now being developed. In this paper the projected possibilities of the MSS system are discussed, including a possibility that a piggyback-MSS payload be added to the GSTAR-4 satellite which is scheduled for a launch in 1988 or 1989; one in which some of the hardware from aborted direct-broadcast satellites would be used; and the possibility of building a new MSS satellite with large servicing capacity. Canada is planning to launch its own mobile satellite, MSAT, in the early 1990s. The MSS is expected to be 'generic', serving not only people on land but maritime and aeronautical users as well. It will also offer major benefits to truck and automobile drivers, making it possible for them to conduct business or to call for assistance from locations beyond the range of cellular systems.

  13. Graphene mobility mapping

    NASA Astrophysics Data System (ADS)

    Buron, Jonas D.; Pizzocchero, Filippo; Jepsen, Peter U.; Petersen, Dirch H.; Caridad, José M.; Jessen, Bjarke S.; Booth, Timothy J.; Bøggild, Peter

    2015-07-01

    Carrier mobility and chemical doping level are essential figures of merit for graphene, and large-scale characterization of these properties and their uniformity is a prerequisite for commercialization of graphene for electronics and electrodes. However, existing mapping techniques cannot directly assess these vital parameters in a non-destructive way. By deconvoluting carrier mobility and density from non-contact terahertz spectroscopic measurements of conductance in graphene samples with terahertz-transparent backgates, we are able to present maps of the spatial variation of both quantities over large areas. The demonstrated non-contact approach provides a drastically more efficient alternative to measurements in contacted devices, with potential for aggressive scaling towards wafers/minute. The observed linear relation between conductance and carrier density in chemical vapour deposition graphene indicates dominance by charged scatterers. Unexpectedly, significant variations in mobility rather than doping are the cause of large conductance inhomogeneities, highlighting the importance of statistical approaches when assessing large-area graphene transport properties.

  14. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  15. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  16. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  17. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  18. 49 CFR 24.502 - Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Replacement housing payment for 180-day mobile homeowner displaced from a mobile home, and/or from the acquired mobile home site. 24.502 Section 24.502... ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.502 Replacement housing payment...

  19. Mobile access control vestibule

    NASA Astrophysics Data System (ADS)

    DePoy, Jennifer M.

    1998-12-01

    The mobile access control vestibule (MACV) is an adaptation of techniques developed for mobile military command centers. The overall configuration of modules acts as an entry control/screening facility or transportable command center. The system would provide the following capabilities: (1) A key element for force protection, rapid deployment units sent to areas having no prepositioned equipment or where there has been a degradation of that equipment as a result of natural disasters or civil unrest. (2) A rapidly deployable security control center to upgrade the security at nonmilitary sites (e.g., diplomatic or humanitarian organizations). (3) Personnel screening, package screening, badge/identification card production for authorized personnel, centralized monitoring of deployed perimeter sensors, and centralized communications for law enforcement personnel. (4) Self-contained screening and threat detection systems, including explosives detection using the system developed by Sandia National Laboratories for the FAA. When coupled with transportable electric generators, the system is self-sufficient. The communication system for the MACV would be a combination of physically wired and wireless communication units that supports by ad hoc networking.

  20. Enhanced two dimensional electron gas transport characteristics in Al{sub 2}O{sub 3}/AlInN/GaN metal-oxide-semiconductor high-electron-mobility transistors on Si substrate

    SciTech Connect

    Freedsman, J. J. Watanabe, A.; Urayama, Y.; Egawa, T.

    2015-09-07

    The authors report on Al{sub 2}O{sub 3}/Al{sub 0.85}In{sub 0.15}N/GaN Metal-Oxide-Semiconductor High-Electron-Mobility Transistor (MOS-HEMT) on Si fabricated by using atomic layer deposited Al{sub 2}O{sub 3} as gate insulator and passivation layer. The MOS-HEMT with the gate length of 2 μm exhibits excellent direct-current (dc) characteristics with a drain current maximum of 1270 mA/mm at a gate bias of 3 V and an off-state breakdown voltage of 180 V for a gate-drain spacing of 4 μm. Also, the 1 μm-gate MOS-HEMT shows good radio-frequency (rf) response such as current gain and maximum oscillation cut-off frequencies of 10 and 34 GHz, respectively. The capacitance-voltage characteristics at 1 MHz revealed significant increase in two-dimensional electron gas (2DEG) density for the MOS-HEMT compared to conventional Schottky barrier HEMTs. Analyses using drain-source conductivity measurements showed improvements in 2DEG transport characteristics for the MOS-HEMT. The enhancements in dc and rf performances of the Al{sub 2}O{sub 3}/Al{sub 0.85}In{sub 0.15}N/GaN MOS-HEMT are attributed to the improvements in 2DEG characteristics.

  1. Logistics Handbook for Strategic Mobility Planning

    DTIC Science & Technology

    1992-09-01

    AD-A257 075 MTMCTEA REFERENCE 92-700-2 LOGISTICS HANDBOOK FOR STRATEGIC 7 DTIGMOBILITY >CT 2 8 1992 SEPTEMBER 1992 MILITARY TRAFFIC MANAGEMENT...unlimited.,, I MTMCTEA Reference 92-700-2 LOGISTICS HANDBOOK FOR STRATEGIC MOBILITY PLANNING September 1992 Aces gaj 0 n For (NTIS cz MILITARY TRAFFIC ...Military Traffic Management Command Transportation Engineering Agency (MTMCTEA) transportation and transportability studies. D. REFERENCES Source references

  2. Defense Transportation Regulation, Part III: Mobility.

    DTIC Science & Technology

    1997-04-11

    or vessel. a. Dromedary . A container that can be mounted behind the power unit of a truck or carried on a flatbed trailer or in a van and which can...Drayage. Movements that originate and terminate within 30 miles of origin. 118. Drive-Away Service. The movement of a vehicle under its own power by...when towed or mounted (either full or saddle mount) upon a vehicle. 119. Dromedary . See Container. 120. Dual Driver Protective Service (DD). A

  3. Transportation Network Topologies

    NASA Technical Reports Server (NTRS)

    Holmes, Bruce J.; Scott, John M.

    2004-01-01

    A discomforting reality has materialized on the transportation scene: our existing air and ground infrastructures will not scale to meet our nation's 21st century demands and expectations for mobility, commerce, safety, and security. The consequence of inaction is diminished quality of life and economic opportunity in the 21st century. Clearly, new thinking is required for transportation that can scale to meet to the realities of a networked, knowledge-based economy in which the value of time is a new coin of the realm. This paper proposes a framework, or topology, for thinking about the problem of scalability of the system of networks that comprise the aviation system. This framework highlights the role of integrated communication-navigation-surveillance systems in enabling scalability of future air transportation networks. Scalability, in this vein, is a goal of the recently formed Joint Planning and Development Office for the Next Generation Air Transportation System. New foundations for 21PstP thinking about air transportation are underpinned by several technological developments in the traditional aircraft disciplines as well as in communication, navigation, surveillance and information systems. Complexity science and modern network theory give rise to one of the technological developments of importance. Scale-free (i.e., scalable) networks represent a promising concept space for modeling airspace system architectures, and for assessing network performance in terms of scalability, efficiency, robustness, resilience, and other metrics. The paper offers an air transportation system topology as framework for transportation system innovation. Successful outcomes of innovation in air transportation could lay the foundations for new paradigms for aircraft and their operating capabilities, air transportation system architectures, and airspace architectures and procedural concepts. The topology proposed considers air transportation as a system of networks, within

  4. Transportation Network Topologies

    NASA Technical Reports Server (NTRS)

    Holmes, Bruce J.; Scott, John

    2004-01-01

    A discomforting reality has materialized on the transportation scene: our existing air and ground infrastructures will not scale to meet our nation's 21st century demands and expectations for mobility, commerce, safety, and security. The consequence of inaction is diminished quality of life and economic opportunity in the 21st century. Clearly, new thinking is required for transportation that can scale to meet to the realities of a networked, knowledge-based economy in which the value of time is a new coin of the realm. This paper proposes a framework, or topology, for thinking about the problem of scalability of the system of networks that comprise the aviation system. This framework highlights the role of integrated communication-navigation-surveillance systems in enabling scalability of future air transportation networks. Scalability, in this vein, is a goal of the recently formed Joint Planning and Development Office for the Next Generation Air Transportation System. New foundations for 21st thinking about air transportation are underpinned by several technological developments in the traditional aircraft disciplines as well as in communication, navigation, surveillance and information systems. Complexity science and modern network theory give rise to one of the technological developments of importance. Scale-free (i.e., scalable) networks represent a promising concept space for modeling airspace system architectures, and for assessing network performance in terms of scalability, efficiency, robustness, resilience, and other metrics. The paper offers an air transportation system topology as framework for transportation system innovation. Successful outcomes of innovation in air transportation could lay the foundations for new paradigms for aircraft and their operating capabilities, air transportation system architectures, and airspace architectures and procedural concepts. The topology proposed considers air transportation as a system of networks, within which

  5. Dynamic Transportation Navigation

    NASA Astrophysics Data System (ADS)

    Meng, Xiaofeng; Chen, Jidong

    Miniaturization of computing devices, and advances in wireless communication and sensor technology are some of the forces that are propagating computing from the stationary desktop to the mobile outdoors. Some important classes of new applications that will be enabled by this revolutionary development include intelligent traffic management, location-based services, tourist services, mobile electronic commerce, and digital battlefield. Some existing application classes that will benefit from the development include transportation and air traffic control, weather forecasting, emergency response, mobile resource management, and mobile workforce. Location management, i.e., the management of transient location information, is an enabling technology for all these applications. In this chapter, we present the applications of moving objects management and their functionalities, in particular, the application of dynamic traffic navigation, which is a challenge due to the highly variable traffic state and the requirement of fast, on-line computations.

  6. Volume 4 - Mobile Sources

    EPA Pesticide Factsheets

    Mobile source reference material for activity data collection from the Emissions Inventory Improvement Program (EIIP). Provides complete methods for collecting key inputs to onroad mobile and nonroad mobile emissions models.

  7. Energy optimization in mobile sensor networks

    NASA Astrophysics Data System (ADS)

    Yu, Shengwei

    Mobile sensor networks are considered to consist of a network of mobile robots, each of which has computation, communication and sensing capabilities. Energy efficiency is a critical issue in mobile sensor networks, especially when mobility (i.e., locomotion control), routing (i.e., communications) and sensing are unique characteristics of mobile robots for energy optimization. This thesis focuses on the problem of energy optimization of mobile robotic sensor networks, and the research results can be extended to energy optimization of a network of mobile robots that monitors the environment, or a team of mobile robots that transports materials from stations to stations in a manufacturing environment. On the energy optimization of mobile robotic sensor networks, our research focuses on the investigation and development of distributed optimization algorithms to exploit the mobility of robotic sensor nodes for network lifetime maximization. In particular, the thesis studies these five problems: 1. Network-lifetime maximization by controlling positions of networked mobile sensor robots based on local information with distributed optimization algorithms; 2. Lifetime maximization of mobile sensor networks with energy harvesting modules; 3. Lifetime maximization using joint design of mobility and routing; 4. Optimal control for network energy minimization; 5. Network lifetime maximization in mobile visual sensor networks. In addressing the first problem, we consider only the mobility strategies of the robotic relay nodes in a mobile sensor network in order to maximize its network lifetime. By using variable substitutions, the original problem is converted into a convex problem, and a variant of the sub-gradient method for saddle-point computation is developed for solving this problem. An optimal solution is obtained by the method. Computer simulations show that mobility of robotic sensors can significantly prolong the lifetime of the whole robotic sensor network while

  8. Cooperating mobile robots

    DOEpatents

    Harrington, John J.; Eskridge, Steven E.; Hurtado, John E.; Byrne, Raymond H.

    2004-02-03

    A miniature mobile robot provides a relatively inexpensive mobile robot. A mobile robot for searching an area provides a way for multiple mobile robots in cooperating teams. A robotic system with a team of mobile robots communicating information among each other provides a way to locate a source in cooperation. A mobile robot with a sensor, a communication system, and a processor, provides a way to execute a strategy for searching an area.

  9. 77 FR 30046 - Ninth Meeting: RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... Satellite (Route) Services AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite... RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services. DATES: The...

  10. 76 FR 66350 - Eighth Meeting: RTCA Special Committee 222 Inmarsat Aeronautical Mobile Satellite (Route) Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-26

    ... Satellite (Route) Services AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Notice of RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route... Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services for the Eighth Meeting. DATES:...

  11. 77 FR 48584 - Tenth Meeting: RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-14

    ... Satellite (Route) Services AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION: Meeting Notice of RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite... RTCA Special Committee 222, Inmarsat Aeronautical Mobile Satellite (Route) Services. DATES: The...

  12. Mobile Schools for a Mobile World

    ERIC Educational Resources Information Center

    Booth, Susan

    2013-01-01

    Overwhelmingly, independent schools are embracing mobile devices--laptops, iPads or other tablets, and smartphones--to enhance teaching and learning. This article describes the results of the "NAIS 2012 Mobile Learning Survey." Among its findings were that 75 percent of NAIS-member schools currently use mobile learning devices in at…

  13. A land mobile satellite data system

    NASA Technical Reports Server (NTRS)

    Kent, John D. B.

    1990-01-01

    The Telesat Mobile Incorporated (TMI) Mobile Data System (MDS) was developed to apply satellite technology to the transportation industry's requirement for a fleet management system. It will provide two-way messaging and automatic position reporting capabilities between dispatch centers and customers' fleets of trucks. The design was based on the Inmarsat L-Band space segment with system link parameters and margins adjusted to meet the land mobile satellite channel characteristics. The system interfaces with the Teleglobe Des Laurentides earth station at Weir, Quebec. The signaling protocols were derived from the Inmarsat Standard C packet signalling system with unique trucking requirements incorporated where necessary.

  14. Transportation Workload Forecasting (TWF) Study.

    DTIC Science & Technology

    1984-01-01

    The findings of this report are not to be construed as an official Department of the Army position, policy , or decision unless so designated by other...15, Mobility Systems Policies , Procedures and Considerations, 2 June 1974, contains approved joint transportation procedures applicable to the...User Ocean Terminals Joint Chiefs of Staff (JCS) Publications JCS Publication 15, Mobility System Policies , Procedures and Considerations C-1 4 4 4

  15. Energy Department to Host First Sustainable Transportation Summit

    SciTech Connect

    Sarkar, Reuben

    2016-06-29

    On July 11-12, mobility and transportation leaders from across the country are coming to Washington, D.C. for the inaugural Sustainable Transportation Summit hosted by the Office of Energy Efficiency and Renewable Energy (EERE).

  16. 76 FR 27745 - Wireless Innovation for Transportation; Request for Information

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-12

    ... advance the Administration's safety, mobility, and environmental sustainability agenda. Feedback and... environmental benefits to both passenger, fleet and freight transportation systems. The WIN for Transportation...., ``nonattainment areas'' as defined by U.S Environmental Protection agency, National Parks, National Monuments,...

  17. Energy Department to Host First Sustainable Transportation Summit

    ScienceCinema

    Sarkar, Reuben

    2016-08-17

    On July 11-12, mobility and transportation leaders from across the country are coming to Washington, D.C. for the inaugural Sustainable Transportation Summit hosted by the Office of Energy Efficiency and Renewable Energy (EERE).

  18. Temperature dependence of ballistic mobility in a metamorphic InGaAs/InAlAs high electron mobility transistor

    SciTech Connect

    Lee, Jongkyong; Gang, Suhyun; Jo, Yongcheol; Kim, Jongmin; Woo, Hyeonseok; Han, Jaeseok; Kim, Hyungsang Im, Hyunsik

    2014-07-28

    We have investigated the temperature dependence of ballistic mobility in a 100 nm-long InGaAs/InAlAs metamorphic high-electron-mobility transistor designed for millimeter-wavelength RF applications. To extract the temperature dependence of quasi-ballistic mobility, our experiment involves measurements of the effective mobility in the low-bias linear region of the transistor and of the collision-dominated Hall mobility using a gated Hall bar of the same epitaxial structure. The data measured from the experiment are consistent with that of modeled ballistic mobility based on ballistic transport theory. These results advance the understanding of ballistic transport in various transistors with a nano-scale channel length that is comparable to the carrier's mean free path in the channel.

  19. Transportation Network Topologies

    NASA Technical Reports Server (NTRS)

    Alexandrov, Natalia (Editor)

    2004-01-01

    The existing U.S. hub-and-spoke air transportation system is reaching saturation. Major aspects of the current system, such as capacity, safety, mobility, customer satisfaction, security, communications, and ecological effects, require improvements. The changing dynamics - increased presence of general aviation, unmanned autonomous vehicles, military aircraft in civil airspace as part of homeland defense - contributes to growing complexity of airspace. The system has proven remarkably resistant to change. NASA Langley Research Center and the National Institute of Aerospace conducted a workshop on Transportation Network Topologies on 9-10 December 2003 in Williamsburg, Virginia. The workshop aimed to examine the feasibility of traditional methods for complex system analysis and design as well as potential novel alternatives in application to transportation systems, identify state-of-the-art models and methods, conduct gap analysis, and thus to lay a foundation for establishing a focused research program in complex systems applied to air transportation.

  20. Anderson Mobility Gap Probed by Dynamic Coherent Backscattering.

    PubMed

    Cobus, L A; Skipetrov, S E; Aubry, A; van Tiggelen, B A; Derode, A; Page, J H

    2016-05-13

    We use dynamic coherent backscattering to study one of the Anderson mobility gaps in the vibrational spectrum of strongly disordered three-dimensional mesoglasses. Comparison of experimental results with the self-consistent theory of localization allows us to estimate the localization (correlation) length as a function of frequency in a wide spectral range covering bands of diffuse transport and a mobility gap delimited by two mobility edges. The results are corroborated by transmission measurements on one of our samples.

  1. The Wellness Mobile: Bringing Preventative Health Services to Rural Communities.

    ERIC Educational Resources Information Center

    Nilson, Ralph; And Others

    1996-01-01

    The Wellness Mobile transports medical supplies, equipment, informational materials, and staff to rural Saskatchewan communities to assist them in developing wellness programs that stress disease prevention. Staff from the Wellness Mobile offer health-risk screening and appraisal to community members and work with local practitioners and schools…

  2. 9 CFR 3.5 - Mobile or traveling housing facilities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Transportation of Dogs and Cats 1 Facilities and Operating Standards § 3.5 Mobile or traveling housing facilities. (a) Heating, cooling, and temperature. Mobile or traveling housing facilities for dogs and cats must be sufficiently heated and cooled when necessary to protect the dogs and cats from temperature...

  3. 9 CFR 3.5 - Mobile or traveling housing facilities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Transportation of Dogs and Cats 1 Facilities and Operating Standards § 3.5 Mobile or traveling housing facilities. (a) Heating, cooling, and temperature. Mobile or traveling housing facilities for dogs and cats must be sufficiently heated and cooled when necessary to protect the dogs and cats from temperature...

  4. 9 CFR 3.5 - Mobile or traveling housing facilities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Transportation of Dogs and Cats 1 Facilities and Operating Standards § 3.5 Mobile or traveling housing facilities. (a) Heating, cooling, and temperature. Mobile or traveling housing facilities for dogs and cats must be sufficiently heated and cooled when necessary to protect the dogs and cats from temperature...

  5. 9 CFR 3.5 - Mobile or traveling housing facilities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Transportation of Dogs and Cats 1 Facilities and Operating Standards § 3.5 Mobile or traveling housing facilities. (a) Heating, cooling, and temperature. Mobile or traveling housing facilities for dogs and cats must be sufficiently heated and cooled when necessary to protect the dogs and cats from temperature...

  6. 9 CFR 3.5 - Mobile or traveling housing facilities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Transportation of Dogs and Cats 1 Facilities and Operating Standards § 3.5 Mobile or traveling housing facilities. (a) Heating, cooling, and temperature. Mobile or traveling housing facilities for dogs and cats must be sufficiently heated and cooled when necessary to protect the dogs and cats from temperature...

  7. Hole mobility in thermally evaporated pentacene: Morphological and directional dependence

    NASA Astrophysics Data System (ADS)

    Günther, Alrun A.; Widmer, Johannes; Kasemann, Daniel; Leo, Karl

    2015-06-01

    Pentacene has been extensively studied as an active material for organic field-effect transistors as it shows very good charge carrier mobility along its preferred transport direction. In this contribution, we investigate the hole transport in pentacene thin films by measurement in conventional lateral organic field-effect transistors (OFETs), which yields the hole mobility along the a-b plane of pentacene, and by the recently published potential mapping (POEM) approach, which allows for direct extraction of the charge carrier mobility perpendicular to the substrate, in this case perpendicular to the a-b plane, without the assumption of a specific transport model. While the mobility along the a-b plane—determined from OFET measurements—is found to be in the region of 0.45 cm2/Vs, transport perpendicular to this plane shows an average mobility at least one order of magnitude lower. Investigating also how these effective mobility values depend on the deposition rate of the pentacene films, we find that the decrease in grain size for increasing deposition rate causes the mobility to decrease both parallel and perpendicular to the substrate due to the increased number of grain boundaries to be overcome. For the out-of-plane transport, this effect is found to saturate for deposition rates higher than 2.5 Å/s.

  8. TRANSPORT AND EMPLACEMENT EQUIPMENT DESCRIPTIONS

    SciTech Connect

    NA

    1997-09-29

    The objective and the scope of this document are to list and briefly describe the major mobile equipment necessary for waste package (WP) Transport and Emplacement in the proposed subsurface nuclear waste repository at Yucca Mountain. Primary performance characteristics and some specialized design features of the equipment are explained and summarized in the individual subsections of this document. The Transport and Emplacement equipment described in this document consists of the following: (1) WP Transporter; (2) Reusable Rail Car; (3) Emplacement Gantry; (4) Gantry Carrier; and (5) Transport Locomotive.

  9. Transportation Statistics Annual Report 1997

    SciTech Connect

    Fenn, M.

    1997-01-01

    This document is the fourth Transportation Statistics Annual Report (TSAR) prepared by the Bureau of Transportation Statistics (BTS) for the President and Congress. As in previous years, it reports on the state of U.S. transportation system at two levels. First, in Part I, it provides a statistical and interpretive survey of the system—its physical characteristics, its economic attributes, aspects of its use and performance, and the scale and severity of unintended consequences of transportation, such as fatalities and injuries, oil import dependency, and environment impacts. Part I also explores the state of transportation statistics, and new needs of the rapidly changing world of transportation. Second, Part II of the report, as in prior years, explores in detail the performance of the U.S. transportation system from the perspective of desired social outcomes or strategic goals. This year, the performance aspect of transportation chosen for thematic treatment is “Mobility and Access,” which complements past TSAR theme sections on “The Economic Performance of Transportation” (1995) and “Transportation and the Environment” (1996). Mobility and access are at the heart of the transportation system’s performance from the user’s perspective. In what ways and to what extent does the geographic freedom provided by transportation enhance personal fulfillment of the nation’s residents and contribute to economic advancement of people and businesses? This broad question underlies many of the topics examined in Part II: What is the current level of personal mobility in the United States, and how does it vary by sex, age, income level, urban or rural location, and over time? What factors explain variations? Has transportation helped improve people’s access to work, shopping, recreational facilities, and medical services, and in what ways and in what locations? How have barriers, such as age, disabilities, or lack of an automobile, affected these

  10. INFLUENCE OF MACROMOLECULES ON CHEMICAL TRANSPORT

    EPA Science Inventory

    Macromolecules in the pore fluid influence the mobility of hydrophobic compounds through soils. his study evaluated the significance of macromolecules in facilitating chemical transport under laboratory conditions. Partition coefficients between 14C-labeled hexachlorobenzene and ...

  11. Tandem mobile robot system

    DOEpatents

    Buttz, James H.; Shirey, David L.; Hayward, David R.

    2003-01-01

    A robotic vehicle system for terrain navigation mobility provides a way to climb stairs, cross crevices, and navigate across difficult terrain by coupling two or more mobile robots with a coupling device and controlling the robots cooperatively in tandem.

  12. Ion mobility sensor system

    DOEpatents

    Xu, Jun; Watson, David B.; Whitten, William B.

    2013-01-22

    An ion mobility sensor system including an ion mobility spectrometer and a differential mobility spectrometer coupled to the ion mobility spectrometer. The ion mobility spectrometer has a first chamber having first end and a second end extending along a first direction, and a first electrode system that generates a constant electric field parallel to the first direction. The differential mobility spectrometer includes a second chamber having a third end and a fourth end configured such that a fluid may flow in a second direction from the third end to the fourth end, and a second electrode system that generates an asymmetric electric field within an interior of the second chamber. Additionally, the ion mobility spectrometer and the differential mobility spectrometer form an interface region. Also, the first end and the third end are positioned facing one another so that the constant electric field enters the third end and overlaps the fluid flowing in the second direction.

  13. ECG by mobile technologies.

    PubMed

    Guzik, Przemyslaw; Malik, Marek

    Mobile electrocardiographs consist of three components: a mobile device (e.g. a smartphone), an electrocardiographic device or accessory, and a mobile application. Mobile platforms are small computers with sufficient computational power, good quality display, suitable data storage, and several possibilities of data transmission. Electrocardiographic electrodes and sensors for mobile use utilize unconventional materials, e.g. rubber, e-textile, and inkjet-printed nanoparticle electrodes. Mobile devices can be handheld, worn as vests or T-shirts, or attached to patient's skin as biopatches. Mobile electrocardiographic devices and accessories may additionally record other signals including respiratory rate, activity level, and geolocation. Large-scale clinical studies that utilize electrocardiography are easier to conduct using mobile technologies and the collected data are suitable for "big data" processing. This is expected to reveal phenomena so far inaccessible by standard electrocardiographic techniques.

  14. Mobility and Young Children.

    ERIC Educational Resources Information Center

    Bernard van Leer Foundation Newsletter, 1994

    1994-01-01

    This newsletter theme issue deals with the phenomenon of mobility or transience in India, Kenya, Greece, Ireland, Malaysia, Thailand and Israel. The primary focus is on mobility's effect on young children, specifically their health and education; some of the broader concerns also addressed by the newsletter are the causes of mobility and its…

  15. Mobile Student Information System

    ERIC Educational Resources Information Center

    Asif, Muhammad; Krogstie, John

    2011-01-01

    Purpose: A mobile student information system (MSIS) based on mobile computing and context-aware application concepts can provide more user-centric information services to students. The purpose of this paper is to describe a system for providing relevant information to students on a mobile platform. Design/methodology/approach: The research…

  16. 49 CFR 24.503 - Replacement housing payment for 90-day mobile home occupants.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Replacement housing payment for 90-day mobile home... Replacement housing payment for 90-day mobile home occupants. A displaced tenant or owner-occupant of a mobile... 90 days immediately prior to the initiation of negotiations; (b) The person meets the other...

  17. 49 CFR 24.503 - Replacement housing payment for 90-day mobile home occupants.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Replacement housing payment for 90-day mobile home... Replacement housing payment for 90-day mobile home occupants. A displaced tenant or owner-occupant of a mobile... 90 days immediately prior to the initiation of negotiations; (b) The person meets the other...

  18. 49 CFR 24.503 - Replacement housing payment for 90-day mobile home occupants.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Replacement housing payment for 90-day mobile home... Replacement housing payment for 90-day mobile home occupants. A displaced tenant or owner-occupant of a mobile... 90 days immediately prior to the initiation of negotiations; (b) The person meets the other...

  19. 49 CFR 392.82 - Using a hand-held mobile telephone.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Using a hand-held mobile telephone. 392.82 Section... COMMERCIAL MOTOR VEHICLES Limiting the Use of Electronic Devices § 392.82 Using a hand-held mobile telephone. (a)(1) No driver shall use a hand-held mobile telephone while driving a CMV. (2) No motor...

  20. 49 CFR 392.82 - Using a hand-held mobile telephone.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Using a hand-held mobile telephone. 392.82 Section... COMMERCIAL MOTOR VEHICLES Limiting the Use of Electronic Devices § 392.82 Using a hand-held mobile telephone. (a)(1) No driver shall use a hand-held mobile telephone while driving a CMV. (2) No motor...

  1. 49 CFR 392.82 - Using a hand-held mobile telephone.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Using a hand-held mobile telephone. 392.82 Section... COMMERCIAL MOTOR VEHICLES Limiting the Use of Electronic Devices § 392.82 Using a hand-held mobile telephone. (a)(1) No driver shall use a hand-held mobile telephone while driving a CMV. (2) No motor...

  2. 49 CFR 24.503 - Replacement housing payment for 90-day mobile home occupants.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Replacement housing payment for 90-day mobile home... ASSISTANCE AND REAL PROPERTY ACQUISITION FOR FEDERAL AND FEDERALLY-ASSISTED PROGRAMS Mobile Homes § 24.503 Replacement housing payment for 90-day mobile home occupants. A displaced tenant or owner-occupant of a...

  3. Radiation Transport

    SciTech Connect

    Urbatsch, Todd James

    2015-06-15

    We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.

  4. Ion mobility sensor

    DOEpatents

    Koo, Jackson C.; Yu, Conrad M.

    2005-08-23

    An ion mobility sensor which can detect both ion and molecules simultaneously. Thus, one can measure the relative arrival times between various ions and molecules. Different ions have different mobility in air, and the ion sensor enables measurement of ion mobility, from which one can identify the various ions and molecules. The ion mobility sensor which utilizes a pair of glow discharge devices may be designed for coupling with an existing gas chromatograph, where various gas molecules are already separated, but numbers of each kind of molecules are relatively small, and in such cases a conventional ion mobility sensor cannot be utilized.

  5. Potential of mobile intraoperative radiotherapy technology.

    PubMed

    Goer, Donald A; Musslewhite, Chapple W; Jablons, David M

    2003-10-01

    Mobile IORT units have the potential to change the way patients who have cancer are treated. The integration of IORT into cancer treatment programs, made possible by the new technologies of mobile linear accelerators that can be used in unshielded operating rooms, makes IORT significantly less time-consuming, less costly, and less risky to administer. It is now practical for IORT to be used in early-stage disease, in addition to advanced disease, and in sites for which patient transportation in the middle of surgery is considered too risky. Preliminary results of trials for early-stage breast and rectal cancer indicate benefits of IORT. Pediatric patients and patients who have lung cancer, previously underserved by IORT therapies, can be offered potential gains when patient transport issues do not limit IORT. Furthermore, because many of these mobile systems require no shielding, it is now practical for mobile units to be shared between hospitals, making this new mobile technology much more widely available.

  6. Mobile Remote Base System (MBS)

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Backdropped against the blackness of space and the Earth's horizon, the Mobile Remote Base System (MBS) is moved by the Canadarm2 for installation on the International Space Station (ISS). Delivered by the STS-111 mission aboard the Space Shuttle Endeavour in June 2002, the MBS is an important part of the Station's Mobile Servicing System allowing the robotic arm to travel the length of the Station, which is neccessary for future construction tasks. In addition, STS-111 delivered a new crew, Expedition Five, replacing Expedition Four after remaining a record-setting 196 days in space. Three spacewalks enabled the STS-111 crew to accomplish the delivery and installation of the MBS to the Mobile Transporter on the S0 (S-zero) truss, the replacement of a wrist roll joint on the Station's robotic arm, and the task of unloading supplies and science experiments from the Leonardo Multi-Purpose Logistics Module, which made its third trip to the orbital outpost. The STS-111 mission, the 14th Shuttle mission to visit the ISS, was launched on June 5, 2002 and landed June 19, 2002.

  7. Mobile applications and Virtual Observatory

    NASA Astrophysics Data System (ADS)

    Schaaff, A.; Jagade, S.

    2015-06-01

    Within a few years, smartphones and Internet tablets have become the devices to access Web or standalone applications from everywhere, with a rapid development of the bandwidth of the mobile networks (e.g. 4G). Internet tablets are used to take notes during meetings or conferences, to read scientific papers in public transportation, etc. A smartphone is for example a way to have your data in the pocket or to control, from everywhere, the progress of a heavy workflow process. These mobile devices have enough powerful hardware to run more and more complex applications for many use cases. In the field of astronomy it is possible to use these tools to access data via a simple browser, but also to develop native applications reusing libraries (written in Java for Android or Objective-C/Swift for iOS) developed for desktops/laptops. We describe the experiments conducted in this domain, at CDS and IUCAA, considering a mobile application as a native application as well as a Web application.

  8. Bulk Superconductors in Mobile Application

    NASA Astrophysics Data System (ADS)

    Werfel, F. N.; Delor, U. Floegel-; Rothfeld, R.; Riedel, T.; Wippich, D.; Goebel, B.; Schirrmeister, P.

    We investigate and review concepts of multi - seeded REBCO bulk superconductors in mobile application. ATZ's compact HTS bulk magnets can trap routinely 1 T@77 K. Except of magnetization, flux creep and hysteresis, industrial - like properties as compactness, power density, and robustness are of major device interest if mobility and light-weight construction is in focus. For mobile application in levitated trains or demonstrator magnets we examine the performance of on-board cryogenics either by LN2 or cryo-cooler application. The mechanical, electric and thermodynamical requirements of compact vacuum cryostats for Maglev train operation were studied systematically. More than 30 units are manufactured and tested. The attractive load to weight ratio is more than 10 and favours group module device constructions up to 5 t load on permanent magnet (PM) track. A transportable and compact YBCO bulk magnet cooled with in-situ 4 Watt Stirling cryo-cooler for 50 - 80 K operation is investigated. Low cooling power and effective HTS cold mass drives the system construction to a minimum - thermal loss and light-weight design.

  9. BACTERIAL TRANSPORT THROUGH HOMOGENEOUS SOIL

    EPA Science Inventory

    The transport of microorganisms in soils is of major importance for bioremediation of subsurface polluted zones and for pollution of groundwater with pathogens. A procedure for evaluating the relative mobility and recovery of bacteria in the soil matrix was developed. In the meth...

  10. FACILITATED TRANSPORT OF INORGANIC CONTAMINANTS IN GROUNDWATER: PART II. COLLOIDAL TRANSPORT

    EPA Science Inventory

    This project consisted of both field and laboratory components. Field studies evaluated routine sampling procedures for determination of aqueous inorganicgeochemistry and assessment of contaminant transport by colloidal mobility. Research at three different metal-contaminated sit...

  11. Emerging needs for mobile nuclear powerplants

    NASA Technical Reports Server (NTRS)

    Anderson, J. L.

    1972-01-01

    Incentives for broadening the present role of civilian nuclear power to include mobile nuclear power plants that are compact, lightweight, and safe are examined. Specifically discussed is the growing importance of: (1) a new international cargo transportation capability, and (2) the capability for development of resources in previously remote regions of the earth including the oceans and the Arctic. This report surveys present and potential systems (vehicles, remote stations, and machines) that would both provide these capabilities and require enough power to justify using mobile nuclear reactor power plants.

  12. ACTS mobile SATCOM experiments

    NASA Technical Reports Server (NTRS)

    Abbe, Brian S.; Frye, Robert E.; Jedrey, Thomas C.

    1993-01-01

    Over the last decade, the demand for reliable mobile satellite communications (satcom) for voice, data, and video applications has increased dramatically. As consumer demand grows, the current spectrum allocation at L-band could become saturated. For this reason, NASA and the Jet Propulsion Laboratory are developing the Advanced Communications Technology Satellites (ACTS) mobile terminal (AMT) and are evaluating the feasibility of K/Ka-band (20/30 GHz) mobile satcom to meet these growing needs. U.S. industry and government, acting as co-partners, will evaluate K/Ka-band mobile satcom and develop new technologies by conducting a series of applications-oriented experiments. The ACTS and the AMT testbed will be used to conduct these mobile satcom experiments. The goals of the ACTS Mobile Experiments Program and the individual experiment configurations and objectives are further presented.

  13. Mobile learning in medicine

    NASA Astrophysics Data System (ADS)

    Serkan Güllüoüǧlu, Sabri

    2013-03-01

    This paper outlines the main infrastructure for implicating mobile learning in medicine and present a sample mobile learning application for medical learning within the framework of mobile learning systems. Mobile technology is developing nowadays. In this case it will be useful to develop different learning environments using these innovations in internet based distance education. M-learning makes the most of being on location, providing immediate access, being connected, and acknowledges learning that occurs beyond formal learning settings, in places such as the workplace, home, and outdoors. Central to m-learning is the principle that it is the learner who is mobile rather than the device used to deliver m learning. The integration of mobile technologies into training has made learning more accessible and portable. Mobile technologies make it possible for a learner to have access to a computer and subsequently learning material and activities; at any time and in any place. Mobile devices can include: mobile phone, personal digital assistants (PDAs), personal digital media players (eg iPods, MP3 players), portable digital media players, portable digital multimedia players. Mobile learning (m-learning) is particularly important in medical education, and the major users of mobile devices are in the field of medicine. The contexts and environment in which learning occurs necessitates m-learning. Medical students are placed in hospital/clinical settings very early in training and require access to course information and to record and reflect on their experiences while on the move. As a result of this paper, this paper strives to compare and contrast mobile learning with normal learning in medicine from various perspectives and give insights and advises into the essential characteristics of both for sustaining medical education.

  14. Mobile computing for radiology.

    PubMed

    Auffermann, William F; Chetlen, Alison L; Sharma, Arjun; Colucci, Andrew T; DeQuesada, Ivan M; Grajo, Joseph R; Kung, Justin W; Loehfelm, Thomas W; Sherry, Steven J

    2013-12-01

    The rapid advances in mobile computing technology have the potential to change the way radiology and medicine as a whole are practiced. Several mobile computing advances have not yet found application to the practice of radiology, while others have already been applied to radiology but are not in widespread clinical use. This review addresses several areas where radiology and medicine in general may benefit from adoption of the latest mobile computing technologies and speculates on potential future applications.

  15. Exploring the mobility of mobile phone users

    NASA Astrophysics Data System (ADS)

    Csáji, Balázs Cs.; Browet, Arnaud; Traag, V. A.; Delvenne, Jean-Charles; Huens, Etienne; Van Dooren, Paul; Smoreda, Zbigniew; Blondel, Vincent D.

    2013-03-01

    Mobile phone datasets allow for the analysis of human behavior on an unprecedented scale. The social network, temporal dynamics and mobile behavior of mobile phone users have often been analyzed independently from each other using mobile phone datasets. In this article, we explore the connections between various features of human behavior extracted from a large mobile phone dataset. Our observations are based on the analysis of communication data of 100,000 anonymized and randomly chosen individuals in a dataset of communications in Portugal. We show that clustering and principal component analysis allow for a significant dimension reduction with limited loss of information. The most important features are related to geographical location. In particular, we observe that most people spend most of their time at only a few locations. With the help of clustering methods, we then robustly identify home and office locations and compare the results with official census data. Finally, we analyze the geographic spread of users’ frequent locations and show that commuting distances can be reasonably well explained by a gravity model.

  16. Doctors going mobile.

    PubMed

    Romano, Ron; Baum, Neil

    2014-01-01

    Having a Web page and a blog site are the minimum requirements for an Internet presence in the new millennium. However, a Web page that loads on a personal computer or a laptop will be ineffective on a mobile or cellular phone. Today, with more existing and potential patients having access to cellular technology, it is necessary to reconfigure the appearance of your Web site that appears on a mobile phone. This article discusses mobile computing and suggestions for improving the appearance of your Web site on a mobile or cellular phone.

  17. First-principles calculations of mobilities in MOSFETs

    NASA Astrophysics Data System (ADS)

    Hadjisavvas, George; Tsetseris, Leonidas; Evans, Matthew; Pantelides, Sokrates

    2007-03-01

    Nano-scale MOSFETs demonstrate interesting electron transport behavior. Straining the silicon lattice results in significant increases in carrier mobility up to 100%. Transport properties are known to depend also on the presence of interface traps. Due to their significance, a large number of studies have obtained mobilities, but in an empirical and semi-classical fashion, whereas, in nano-devices quantum mechanical effects and atomic-scale structural details are the key factors of mobility calculations. Here we use a recently developed method[1] for first-principles calculations of mobilites within DFT to probe the effect of strain and interface point defects (e.g., dangling bonds) on mobilities in double gate ultra-thin SOI (UTSOI) MOSFETs. The transport properties are described in a fully self-consistent quantum mechanical fashion and mobilities are calculated within the Born approximation. The results show that biaxial tensile strain is shown to significantly increase carrier mobility in UTSOI devices by suppressing the effective scattering from atomic-scale interface inhomogeneities; the effect of dangling bonds on mobility in a UTSOI channel is weaker than in conventional MOSFETs because the carrier density peaks at the center of the channel. This work was supported in part by NSF Grant ECS-0524655 and by AFOSR Grant 4224224232. [1] M.H. Evans et al., Phys. Rev. Lett. 95, 106802 (2005).

  18. Colloid mobilization by fluid displacement fronts in channels.

    PubMed

    Lazouskaya, Volha; Wang, Lian-Ping; Or, Dani; Wang, Gang; Caplan, Jeffrey L; Jin, Yan

    2013-09-15

    Understanding colloid mobilization during transient flow in soil is important for addressing colloid and contaminant transport issues. While theoretical descriptions of colloid detachment exist for saturated systems, corresponding mechanisms of colloid mobilization during drainage and imbibition have not been considered in detail. In this work, theoretical force and torque analyses were performed to examine the interactive effects of adhesion, drag, friction, and surface tension forces on colloid mobilization and to outline conditions corresponding to the mobilization mechanisms such as lifting, sliding, and rolling. Colloid and substrate contact angles were used as variables to determine theoretical criteria for colloid mobilization mechanisms during drainage and imbibition. Experimental mobilization of hydrophilic and hydrophobic microspheres with drainage and imbibition fronts was investigated in hydrophilic and hydrophobic channels using a confocal microscope. Colloid mobilization differed between drainage and imbibition due to different dynamic contact angles and interfacial geometries on the contact line. Experimental results did not fully follow the theoretical criteria in all cases, which was explained with additional factors not included in the theory such as presence of aggregates and trailing films. Theoretical force and torque analyses resulted in similar mobilization predictions and suggested that all mobilization mechanisms contributed to the observed colloid mobilization.

  19. Mobile Spectroscopic Instrumentation in Archaeometry Research.

    PubMed

    Vandenabeele, Peter; Donais, Mary Kate

    2016-01-01

    Mobile instrumentation is of growing importance to archaeometry research. Equipment is utilized in the field or at museums, thus avoiding transportation or risk of damage to valuable artifacts. Many spectroscopic techniques are nondestructive and micro-destructive in nature, which preserves the cultural heritage objects themselves. This review includes over 160 references pertaining to the use of mobile spectroscopy for archaeometry. Following a discussion of terminology related to mobile instrumental methods, results of a literature survey on their applications for cultural heritage objects is presented. Sections devoted to specific techniques are then provided: Raman spectroscopy, X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, laser-induced breakdown spectroscopy, and less frequently used techniques. The review closes with a discussion of combined instrumental approaches.

  20. Reconfigurable mobile manipulation for accident response

    SciTech Connect

    ANDERSON,ROBERT J.; MORSE,WILLIAM D.; SHIREY,DAVID L.; CDEBACA,DANIEL M.; HOFFMAN JR.,JOHN P.; LUCY,WILLIAM E.

    2000-06-06

    The need for a telerobotic vehicle with hazard sensing and integral manipulation capabilities has been identified for use in transportation accidents where nuclear weapons are involved. The Accident Response Mobile Manipulation System (ARMMS) platform has been developed to provide remote dexterous manipulation and hazard sensing for the Accident Response Group (ARG) at Sandia National Laboratories. The ARMMS' mobility platform is a military HMMWV [High Mobility Multipurpose Wheeled Vehicle] that is teleoperated over RF or Fiber Optic communication channels. ARMMS is equipped with two high strength Schilling Titan II manipulators and a suite of hazardous gas and radiation sensors. Recently, a modular telerobotic control architecture call SMART (Sandia Modular Architecture for Robotic and Teleoperation) has been applied to ARMMS. SMART enables input devices and many system behaviors to be rapidly configured in the field for specific mission needs. This paper summarizes current SMART developments applied to ARMMS.

  1. International aircraft ECMO transportation: first French pediatric experience.

    PubMed

    Rambaud, Jerome; Léger, Pierre L; Porlier, Ludovic; Larroquet, Michelle; Raffin, Herve; Pierron, Charlotte; Walti, Herve; Carbajal, Ricardo

    2017-04-01

    Refractory severe hemodynamic or respiratory failure may require extracorporeal membrane oxygenation (ECMO). Since some patients are too sick to be transported safely to a referral ECMO center on conventional transportation, mobile ECMO transport teams have been developed. The experiences of some ECMO transport teams have already been reported, including air and international transport. We report the first French pediatric international ECMO transport by aircraft. This case shows that a long distance intervention of the pediatric ECMO transport team is feasible, even in an international setting. Long distance ECMO transportations are widely carried out for adults, but remain rare in neonates and children.

  2. Charge carrier mobility in hybrid halide perovskites.

    PubMed

    Motta, Carlo; El-Mellouhi, Fedwa; Sanvito, Stefano

    2015-08-03

    The charge transport properties of hybrid halide perovskites are investigated with a combination of density functional theory including van der Waals interaction and the Boltzmann theory for diffusive transport in the relaxation time approximation. We find the mobility of electrons to be in the range 5-10 cm(2)V(-1)s(-1) and that for holes within 1-5 cm(2)V(-1)s(-1), where the variations depend on the crystal structure investigated and the level of doping. Such results, in good agreement with recent experiments, set the relaxation time to about 1 ps, which is the time-scale for the molecular rotation at room temperature. For the room temperature tetragonal phase we explore two possible orientations of the organic cations and find that the mobility has a significant asymmetry depending on the direction of the current with respect to the molecular axis. This is due mostly to the way the PbI3 octahedral symmetry is broken. Interestingly we find that substituting I with Cl has minor effects on the mobilities. Our analysis suggests that the carrier mobility is probably not a key factor in determining the high solar-harvesting efficiency of this class of materials.

  3. Adapting End Host Congestion Control for Mobility

    NASA Technical Reports Server (NTRS)

    Eddy, Wesley M.; Swami, Yogesh P.

    2005-01-01

    Network layer mobility allows transport protocols to maintain connection state, despite changes in a node's physical location and point of network connectivity. However, some congestion-controlled transport protocols are not designed to deal with these rapid and potentially significant path changes. In this paper we demonstrate several distinct problems that mobility-induced path changes can create for TCP performance. Our premise is that mobility events indicate path changes that require re-initialization of congestion control state at both connection end points. We present the application of this idea to TCP in the form of a simple solution (the Lightweight Mobility Detection and Response algorithm, that has been proposed in the IETF), and examine its effectiveness. In general, we find that the deficiencies presented are both relatively easily and painlessly fixed using this solution. We also find that this solution has the counter-intuitive property of being both more friendly to competing traffic, and simultaneously more aggressive in utilizing newly available capacity than unmodified TCP.

  4. Charge carrier mobility in hybrid halide perovskites

    PubMed Central

    Motta, Carlo; El-Mellouhi, Fedwa; Sanvito, Stefano

    2015-01-01

    The charge transport properties of hybrid halide perovskites are investigated with a combination of density functional theory including van der Waals interaction and the Boltzmann theory for diffusive transport in the relaxation time approximation. We find the mobility of electrons to be in the range 5–10 cm2V−1s−1 and that for holes within 1–5 cm2V−1s−1, where the variations depend on the crystal structure investigated and the level of doping. Such results, in good agreement with recent experiments, set the relaxation time to about 1 ps, which is the time-scale for the molecular rotation at room temperature. For the room temperature tetragonal phase we explore two possible orientations of the organic cations and find that the mobility has a significant asymmetry depending on the direction of the current with respect to the molecular axis. This is due mostly to the way the PbI3 octahedral symmetry is broken. Interestingly we find that substituting I with Cl has minor effects on the mobilities. Our analysis suggests that the carrier mobility is probably not a key factor in determining the high solar-harvesting efficiency of this class of materials. PMID:26235910

  5. Mobile Goes Mainstream

    ERIC Educational Resources Information Center

    Eisele-Dyrli, Kurt

    2011-01-01

    Mobile learning--the use of mobile devices for educational purposes by students--is rapidly moving from an experimental initiative by a few innovative districts over the last five years to a broadly accepted concept in K12. The latest research and surveys, results of pilot programs, and analysis of trends in both public education and the broader…

  6. Mobile Christian - shuttle flight

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Erin Whittle, 14, (seated) and Brianna Johnson, 14, look on as Louis Stork, 13, attempts a simulated landing of a space shuttle at StenniSphere. The young people were part of a group from Mobile Christian School in Mobile, Ala., that visited StenniSphere on April 21.

  7. Mobile Learning Anytime, Anywhere

    ERIC Educational Resources Information Center

    Hlodan, Oksana

    2010-01-01

    Some educational institutions are taking the leap to mobile learning (m-learning) by giving out free iPods. For example, Abilene Christian University gave iPods or iPhones to freshman students and developed 15 Web applications specifically for the mobile devices. The iPod is not the only ubiquitous m-learning device. Any technology that connects…

  8. Increasing mobile radiography productivity.

    PubMed

    Wong, Edward; Lung, Ngan Tsz; Ng, Kris; Jeor, Patrick

    2013-01-01

    Mobile radiography using computed radiography (CR) cassettes is a common equipment combination with a workflow bottleneck limited by location of CR readers. Advent of direct digital radiography (DDR) mobile x-ray machines removes this limitation by immediate image review and quality control. Through the use of key performance indicators (KPIs), the increase in efficiency can be quantified.

  9. Mastering Mobile Security

    ERIC Educational Resources Information Center

    Panettieri, Joseph C.

    2007-01-01

    Without proper security, mobile devices are easy targets for worms, viruses, and so-called robot ("bot") networks. Hackers increasingly use bot networks to launch massive attacks against eCommerce websites--potentially targeting one's online tuition payment or fundraising/financial development systems. How can one defend his mobile systems against…

  10. Mobility Test Article (MTA)

    NASA Technical Reports Server (NTRS)

    1965-01-01

    A concept of a possible Lunar Roving Vehicle (LRV) built for NASA's Marshall Space Flight Center (MSFC). This Mobility Test Article (MTA) is one of many that provided data contributing to the design of the LRV, developed under the direction of MSFC. The LRV was designed to allow Apollo astronauts a greater range of mobility during lunar exploration missions.

  11. Mobile Apps for Librarians

    ERIC Educational Resources Information Center

    Power, June L.

    2013-01-01

    In an increasing mobile environment, library and reading-related activities often take place on a phone or tablet device. Not only does this mean that library Web sites must keep mobile navigability in mind, but also develop and utilize apps that allow patrons to interact with information and with libraries. While apps do not serve every purpose,…

  12. ACTS Mobile Terminals

    NASA Technical Reports Server (NTRS)

    Abbe, Brian S.; Agan, Martin J.; Jedrey, Thomas C.

    1997-01-01

    The development of the Advanced Communications Technology Satellite (ACTS) Mobile Terminal (AMT) and its follow-on, the Broadband Aeronautical Terminal (BAT), have provided an excellent testbed for the evaluation of K- and Ka-band mobile satellite communications systems. An overview of both of these terminals is presented in this paper.

  13. Transport Experiments

    NASA Technical Reports Server (NTRS)

    Hall, Timothy M.; Wuebbles, Donald J.; Boering, Kristie A.; Eckman, Richard S.; Lerner, Jean; Plumb, R. Alan; Rind, David H.; Rinsland, Curtis P.; Waugh, Darryn W.; Wei, Chu-Feng

    1999-01-01

    MM II defined a series of experiments to better understand and characterize model transport and to assess the realism of this transport by comparison to observations. Measurements from aircraft, balloon, and satellite, not yet available at the time of MM I [Prather and Remsberg, 1993], provide new and stringent constraints on model transport, and address the limits of our transport modeling abilities. Simulations of the idealized tracers the age spectrum, and propagating boundary conditions, and conserved HSCT-like emissions probe the relative roles of different model transport mechanisms, while simulations of SF6 and C02 make the connection to observations. Some of the tracers are related, and transport diagnostics such as the mean age can be derived from more than one of the experiments for comparison to observations. The goals of the transport experiments are: (1) To isolate the effects of transport in models from other processes; (2) To assess model transport for realistic tracers (such as SF6 and C02) for comparison to observations; (3) To use certain idealized tracers to isolate model mechanisms and relationships to atmospheric chemical perturbations; (4) To identify strengths and weaknesses of the treatment of transport processes in the models; (5) To relate evaluated shortcomings to aspects of model formulation. The following section are included:Executive Summary, Introduction, Age Spectrum, Observation, Tropical Transport in Models, Global Mean Age in Models, Source-Transport Covariance, HSCT "ANOY" Tracer Distributions, and Summary and Conclusions.

  14. Measurement of Transport Properties of Aerosolized Nanomaterials

    PubMed Central

    Ku, Bon Ki; Kulkarni, Pramod

    2015-01-01

    Airborne engineered nanomaterials such as single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), functionalized MWCNT, graphene, fullerene, silver and gold nanorods were characterized using a tandem system of a differential mobility analyzer and an aerosol particle mass analyzer to obtain their airborne transport properties and understand their relationship to morphological characteristics. These nanomaterials were aerosolized using different generation methods such as electrospray, pneumatic atomization, and dry aerosolization techniques, and their airborne transport properties such as mobility and aerodynamic diameters, mass scaling exponent, dynamic shape factor, and effective density were obtained. Laboratory experiments were conducted to directly measure mobility diameter and mass of the airborne nanomaterials using tandem mobility-mass measurements. Mass scaling exponents, aerodynamic diameters, dynamic shape factors and effective densities of mobility-classified particles were obtained from particle mass and the mobility diameter. Microscopy analysis using Transmission Electron Microscopy (TEM) was performed to obtain morphological descriptors such as envelop diameter, open area, aspect ratio, and projected area diameter. The morphological information from the TEM was compared with measured aerodynamic and mobility diameters of the particles. The results showed that aerodynamic diameter is smaller than mobility diameter below 500 nm by a factor of 2 to 4 for all nanomaterials except silver and gold nanorods. Morphologies of MWCNTs generated by liquid-based method, such as pneumatic atomization, are more compact than those of dry dispersed MWCNTs, indicating that the morphology depends on particle generation method. TEM analysis showed that projected area diameter of MWCNTs appears to be in reasonable agreement with mobility diameter in the size range from 100 – 400 nm. Principal component analysis of the obtained airborne particle

  15. Gone Mobile? (Mobile Libraries Survey 2010)

    ERIC Educational Resources Information Center

    Thomas, Lisa Carlucci

    2010-01-01

    Librarians, like patrons and researchers, are caught between traditional library service models and the promise of evolving information technologies. In recent years, professional conferences have strategically featured programs and presentations geared toward building a mobile agenda and adapting or adopting services to meet new demands of mobile…

  16. Mobile assistive technologies for the visually impaired.

    PubMed

    Hakobyan, Lilit; Lumsden, Jo; O'Sullivan, Dympna; Bartlett, Hannah

    2013-01-01

    There are around 285 million visually impaired people worldwide, and around 370,000 people are registered as blind or partially sighted in the UK. Ongoing advances in information technology (IT) are increasing the scope for IT-based mobile assistive technologies to facilitate the independence, safety, and improved quality of life of the visually impaired. Research is being directed at making mobile phones and other handheld devices accessible via our haptic (touch) and audio sensory channels. We review research and innovation within the field of mobile assistive technology for the visually impaired and, in so doing, highlight the need for successful collaboration between clinical expertise, computer science, and domain users to realize fully the potential benefits of such technologies. We initially reflect on research that has been conducted to make mobile phones more accessible to people with vision loss. We then discuss innovative assistive applications designed for the visually impaired that are either delivered via mainstream devices and can be used while in motion (e.g., mobile phones) or are embedded within an environment that may be in motion (e.g., public transport) or within which the user may be in motion (e.g., smart homes).

  17. Land mobile services of Inmarsat.

    NASA Astrophysics Data System (ADS)

    Bell, J.-C.

    1991-04-01

    Inmarsat is the sole satellite organization with global L-band capacity uniquely placed to serve all areas of the world and quickly develop potential markets for land mobile services. The Standard-A system is currently in use, with terminals mounted either in vehicles or moved from one site to another in transportable configurations. Attention is given to the way these terminals provide fax, telex, voice and voice-band data connections with the international public switched networks. An enhanced Standard-C system for messaging and data communications, having a small omnidirectional antenna that can be mounted in any ground vehicle to provide general two-way messaging or automatic position reporting, is presented.

  18. Mobile remote manipulator vehicle system

    NASA Technical Reports Server (NTRS)

    Bush, Harold G. (Inventor); Mikulas, Martin M., Jr. (Inventor); Wallsom, Richard E. (Inventor); Jensen, J. Kermit (Inventor)

    1987-01-01

    A mobile remote manipulator system is disclosed for assembly, repair and logistics transport on, around and about a space station square bay truss structure. The vehicle is supported by a square track arrangement supported by guide pins integral with the space station truss structure and located at each truss node. Propulsion is provided by a central push-pull drive mechanism that extends out from the vehicle one full structural bay over the truss and locks drive rods into the guide pins. The draw bar is now retracted and the mobile remote manipulator system is pulled onto the next adjacent structural bay. Thus, translation of the vehicle is inchworm style. The drive bar can be locked onto two guide pins while the extendable draw bar is within the vehicle and then push the vehicle away one bay providing bidirectional push-pull drive. The track switches allow the vehicle to travel in two orthogonal directions over the truss structure which coupled with the bidirectional drive, allow movement in four directions on one plane. The top layer of this trilayered vehicle is a logistics platform. This platform is capable of 369 degees of rotation and will have two astronaut foot restraint platforms and a space crane integral.

  19. Charge carrier mobility in an organic-inorganic hybrid nanocomposite

    NASA Astrophysics Data System (ADS)

    Choudhury, Kaushik Roy; Winiarz, Jeffrey G.; Samoc, Marek; Prasad, Paras N.

    2003-01-01

    Organic-inorganic hybrid materials are media for electronic and optoelectronic applications. We present a study of the electronic transport in such a model nanoparticle-sensitized hybrid organic-inorganic photorefractive host system, consisting of poly(N-vinylcarbazole) doped with quantum dots of cadmium sulfide, using standard time-of-flight techniques. The photocurrent transients exhibit features typical of dispersive transport in an amorphous semiconductor. The hole mobility depends strongly on the electric field and temperature indicating Poole-Frenkel-like activated hopping transport; a thickness dependence of the mobility is observed. The presence of nanoparticles does not lead to increased trapping of holes. Conversely, a surprising result is observed: the mobility actually increases with the increase of nanoparticle concentration even though it is well below the percolation limit.

  20. Limits of social mobilization

    PubMed Central

    Rutherford, Alex; Cebrian, Manuel; Dsouza, Sohan; Moro, Esteban; Pentland, Alex; Rahwan, Iyad

    2013-01-01

    The Internet and social media have enabled the mobilization of large crowds to achieve time-critical feats, ranging from mapping crises in real time, to organizing mass rallies, to conducting search-and-rescue operations over large geographies. Despite significant success, selection bias may lead to inflated expectations of the efficacy of social mobilization for these tasks. What are the limits of social mobilization, and how reliable is it in operating at these limits? We build on recent results on the spatiotemporal structure of social and information networks to elucidate the constraints they pose on social mobilization. We use the DARPA Network Challenge as our working scenario, in which social media were used to locate 10 balloons across the United States. We conduct high-resolution simulations for referral-based crowdsourcing and obtain a statistical characterization of the population recruited, geography covered, and time to completion. Our results demonstrate that the outcome is plausible without the presence of mass media but lies at the limit of what time-critical social mobilization can achieve. Success relies critically on highly connected individuals willing to mobilize people in distant locations, overcoming the local trapping of diffusion in highly dense areas. However, even under these highly favorable conditions, the risk of unsuccessful search remains significant. These findings have implications for the design of better incentive schemes for social mobilization. They also call for caution in estimating the reliability of this capability. PMID:23576719

  1. Mobile Sensing Systems

    PubMed Central

    Macias, Elsa; Suarez, Alvaro; Lloret, Jaime

    2013-01-01

    Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular… Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high. PMID:24351637

  2. Mobile sensing systems.

    PubMed

    Macias, Elsa; Suarez, Alvaro; Lloret, Jaime

    2013-12-16

    Rich-sensor smart phones have made possible the recent birth of the mobile sensing research area as part of ubiquitous sensing which integrates other areas such as wireless sensor networks and web sensing. There are several types of mobile sensing: individual, participatory, opportunistic, crowd, social, etc. The object of sensing can be people-centered or environment-centered. The sensing domain can be home, urban, vehicular… Currently there are barriers that limit the social acceptance of mobile sensing systems. Examples of social barriers are privacy concerns, restrictive laws in some countries and the absence of economic incentives that might encourage people to participate in a sensing campaign. Several technical barriers are phone energy savings and the variety of sensors and software for their management. Some existing surveys partially tackle the topic of mobile sensing systems. Published papers theoretically or partially solve the above barriers. We complete the above surveys with new works, review the barriers of mobile sensing systems and propose some ideas for efficiently implementing sensing, fusion, learning, security, privacy and energy saving for any type of mobile sensing system, and propose several realistic research challenges. The main objective is to reduce the learning curve in mobile sensing systems where the complexity is very high.

  3. Limits of social mobilization.

    PubMed

    Rutherford, Alex; Cebrian, Manuel; Dsouza, Sohan; Moro, Esteban; Pentland, Alex; Rahwan, Iyad

    2013-04-16

    The Internet and social media have enabled the mobilization of large crowds to achieve time-critical feats, ranging from mapping crises in real time, to organizing mass rallies, to conducting search-and-rescue operations over large geographies. Despite significant success, selection bias may lead to inflated expectations of the efficacy of social mobilization for these tasks. What are the limits of social mobilization, and how reliable is it in operating at these limits? We build on recent results on the spatiotemporal structure of social and information networks to elucidate the constraints they pose on social mobilization. We use the DARPA Network Challenge as our working scenario, in which social media were used to locate 10 balloons across the United States. We conduct high-resolution simulations for referral-based crowdsourcing and obtain a statistical characterization of the population recruited, geography covered, and time to completion. Our results demonstrate that the outcome is plausible without the presence of mass media but lies at the limit of what time-critical social mobilization can achieve. Success relies critically on highly connected individuals willing to mobilize people in distant locations, overcoming the local trapping of diffusion in highly dense areas. However, even under these highly favorable conditions, the risk of unsuccessful search remains significant. These findings have implications for the design of better incentive schemes for social mobilization. They also call for caution in estimating the reliability of this capability.

  4. Establishing reference condition for streambed mobility: Quantifying the effect of form roughness from stream habitat survey data

    EPA Science Inventory

    The size and mobility of streambed particles are sensitive to changes in the balance between sediment supply and transport. Therefore, changes in mobility can be an indicator of natural or anthropogenic alterations in this balance. Predictions of the critical diameter for mobil...

  5. Mobile sociology. 2000.

    PubMed

    Urry, John

    2010-01-01

    This article seeks to develop a manifesto for a sociology concerned with the diverse mobilities of peoples, objects, images, information, and wastes; and of the complex interdependencies between, and social consequences of, such diverse mobilities. A number of key concepts relevant for such a sociology are elaborated: 'gamekeeping', networks, fluids, scapes, flows, complexity and iteration. The article concludes by suggesting that a 'global civil society' might constitute the social base of a sociology of mobilities as we move into the twenty-first century.

  6. Land mobile satellite systems

    NASA Astrophysics Data System (ADS)

    Kiesling, John D.

    1990-07-01

    The general advantages and potential operating characteristics of the mobile satellite service (MSS) are described, and distinctions are made between radio telephone, which is interconnected to the public switched telephone network, and private mobile radio systems. Mobile satellite service offers voice, data, position location, and paging services, interconnection to the public switched telephone network, and the possibility of private networks. Performance and cost characteristics are given along with summaries of market needs and market demands. The space and ground systems of the MSS are described.

  7. Counterion Effects on Ion Mobility and Mobile Ion Concentration of Doped Polyphosphazenes and Polyphosphazene Ionomers

    NASA Astrophysics Data System (ADS)

    Runt, Jim; Klein, Robert

    2007-03-01

    Previous investigations have shed some light on the ion conduction process in polymer electrolytes, yet ion transport is still not well understood. Here, upon the application of a physical model of electrode polarization to two systems with nearly identical chemical structure, one composed of an ionomer (MI) with a single mobile cation, and the other a salt-doped polymer (M+S) with mobile cation and mobile anion, quantitative comparison of the conductivity parameters is achieved. The polymer electrolyte chemistries of both MI and M+S are based on poly(methoxyethoxy-ethoxy phosphazene) (MEEP). The glass transition was found to be an important factor governing the conductivity and ion mobility. However, even accounting for the glass transition, the mobility of ions in the M+S system is 10 times larger than that in the MI system, which must arise from faster diffusion of the anion than the cation. Values for mobile ion concentration are also approximately 10 times higher in M+S than MI. These differences originate from free volume available for diffusion and local environment surrounding the ion pairs, demonstrating that the location of the ion pairs in the polymer matrix has a crucial effect on both conductivity parameters. Research supported by NSF Polymers Program.

  8. Ridesharing and transportation for the disadvantaged. Transportation research record

    SciTech Connect

    Lauritzen, T.; McKelvey, F.X.; Lyles, R.W.; Lighthizer, D.R.; Hardy, D.K.

    1988-01-01

    The 11 papers in the report deal with the following areas: a 1-year review of performance measures for the Chicago transit authority's special services contracted service for the elderly and handicapped; evaluation of a demonstration small bus program for the elderly and handicapped; travel mode choice behavior and physical barrier constraints among the elderly and handicapped: an examination of travel-mode preferences; the role of private enterprise in elderly and handicapped transportation in Canada; special transportation-service in Sweden--involvement of private operators; role of the private sector in the delivery of transportation services to the elderly and handicapped in the United States; suburban activity center transportation demand management market research study; commuting behavior of Hawaii state workers in Honolulu: implications for transportation system management strategies; mobility and specialized transportation for elderly and for disabled persons: a view from four selected countries; an inventory of twelve paratransit service delivery experiences; integrating social-service client transportation and special needs transportation systems: the Portland experience.

  9. A Rapid Screen Technique for Estimating Nanoparticle Transport in Porous Media

    EPA Science Inventory

    Quantifying the mobility of engineered nanoparticles in hydrologic pathways from point of release to human or ecological receptors is essential for assessing environmental exposures. Column transport experiments are a widely used technique to estimate the transport parameters of ...

  10. Photonic sensor applications in transportation security

    NASA Astrophysics Data System (ADS)

    Krohn, David A.

    2007-09-01

    There is a broad range of security sensing applications in transportation that can be facilitated by using fiber optic sensors and photonic sensor integrated wireless systems. Many of these vital assets are under constant threat of being attacked. It is important to realize that the threats are not just from terrorism but an aging and often neglected infrastructure. To specifically address transportation security, photonic sensors fall into two categories: fixed point monitoring and mobile tracking. In fixed point monitoring, the sensors monitor bridge and tunnel structural health and environment problems such as toxic gases in a tunnel. Mobile tracking sensors are being designed to track cargo such as shipboard cargo containers and trucks. Mobile tracking sensor systems have multifunctional sensor requirements including intrusion (tampering), biochemical, radiation and explosives detection. This paper will review the state of the art of photonic sensor technologies and their ability to meet the challenges of transportation security.

  11. The mobile Water vapor Aerosol Raman LIdar and its implication in the framework of the HyMeX and ChArMEx programs: application to a dust transport process

    NASA Astrophysics Data System (ADS)

    Chazette, P.; Marnas, F.; Totems, J.

    2014-06-01

    The increasing importance of the coupling of water and aerosol cycles in environmental applications requires observation tools that allow simultaneous measurements of these two fundamental processes for climatological and meteorological studies. For this purpose, a new mobile Raman lidar, WALI (Water vapor and Aerosol LIdar), has been developed and implemented within the framework of the international HyMeX and ChArMEx programs. This paper presents the key properties of this new device and its first applications to scientific studies. The lidar uses an eye-safe emission in the ultraviolet range at 354.7 nm and a set of compact refractive receiving telescopes. Cross-comparisons between rawinsoundings performed from balloon or aircraft and lidar measurements have shown a good agreement in the derived water vapor mixing ratio (WVMR). The discrepancies are generally less than 0.5 g kg-1 and therefore within the error bars of the respective instruments. A detailed study of the uncertainty of the WVMR retrieval was conducted and shows values between 7 and 11%, which is largely constrained by the quality of the lidar calibration. It also proves that the lidar is able to measure the WVMR during daytime over a range of about 1 km. In addition the WALI system provides measurements of aerosol optical properties such as the lidar ratio (LR) or the particulate depolarization ratio (PDR). An important example of scientific application addressing the main objectives of the HyMeX and ChArMEx programs is then presented, following an event of desert dust aerosols over the Balearic Islands in October 2012. This dust intrusion may have had a significant impact on the intense precipitations that occurred over southwestern France and the Spanish Mediterranean coasts. During this event, the LR and PDR values obtained are in the ranges of ~45-63 ± 6 and 0.10-0.19 ± 0.01 sr, respectively, which is representative of dust aerosols. The dust layers are also shown to be associated with

  12. The mobile Water vapor Aerosol Raman LIdar and its implication in the frame of the HyMeX and ChArMEx programs: application to a dust transport process

    NASA Astrophysics Data System (ADS)

    Chazette, P.; Marnas, F.; Totems, J.

    2013-12-01

    The increasing importance of the coupling of water and aerosol cycles in environmental applications requires observation tools which allow simultaneous measurements of these two fundamental processes for climatological and meteorological studies. In this purpose, a new mobile Raman lidar, WALI (Water vapor and Aerosol LIDAR), has been developed and implemented within the framework of the international HyMeX/IODA-MED and ChArMEx programs. This paper presents the key properties of this new device and its first applications to scientific studies. The lidar uses an eye-safe emission in the ultra-violet range at 354.7 nm and a set of compact refractive receptors. Cross-comparisons between rawindsoundings performed from balloon or aircraft and lidar measurements have shown a good agreement in the derived water vapor mixing ratio (WVMR). The discrepancies are generally less than 0.5 g kg-1 and therefore within the error bars of the instruments. A detailed study of the uncertainties was conducted and shows a 7 to 11% accuracy of the WVMR retrieval, which is largely constrained by the quality of the calibration. It also proves that the lidar is able to measure the WVMR during the day over a range of about 1 km. The WALI system otherwise provides measurements of aerosol optical properties such as the lidar ratio (LR) or the particulate depolarization ratio (PDR). An important example of scientific application addressing the main objectives of the HyMeX and ChArMEx programs is then presented, following an event of desert dust aerosols over the Balearic Islands. This dust intrusion may have had a significant impact on the intense precipitations that occurred over southwestern France and the Spanish Mediterranean coasts. During this event, the LR and PDR values obtained are in the ranges of ~ 45-63 ± 6 sr and 0.1-0.19 ± 0.01, respectively, which is representative of dust aerosols. The dust layers are also shown to be associated with significant WVMR, i.e. between 4 and 6.7 g

  13. Persuasive Mobile Health Applications

    NASA Astrophysics Data System (ADS)

    Garcia Wylie, Carlos; Coulton, Paul

    With many industrialized societies bearing the cost of an increasingly sedentary lifestyle on the health of their populations there is a need to find new ways of encouraging physical activity to promote better health and well being. With the increasing power of mobile phones and the recent emergence of personal heart rate monitors, aimed at dedicated amateur runners, there is now a possibility to develop “Persuasive Mobile Health Applications” to promote well being through the use of real-time physiological data and persuade users to adopt a healthier lifestyle. In this paper we present a novel general health monitoring software for mobile phones called Heart Angel. This software is aimed at helping users monitor, record, as well as improve their fitness level through built-in cardio-respiratory tests, a location tracking application for analyzing heart rate exertion over time and location, and a fun mobile-exergame called Health Defender.

  14. Intelligent Mobility Systems: Some Socio-technical Challenges and Opportunities

    NASA Astrophysics Data System (ADS)

    Büscher, Monika; Coulton, Paul; Efstratiou, Christos; Gellersen, Hans; Hemment, Drew; Mehmood, Rashid; Sangiorgi, Daniela

    Analysis of socio-technical challenges and opportunities around contemporary mobilities suggests new interpretations and visions for intelligent transport systems. Multiple forms of intelligence are required (but not easily compatible), transport is too narrow a term, and innovation results in new socio-technical systems. An exploration of cumulative, collective and collaborative aspects of mobility systems, allows us to sketch challenges and opportunities in relation to practices of collaboration, communication and coordination, literacies for creativity, comfort and control, citizenship and (lack of) a sense of crisis, concluding with a discussion of methodological implications.

  15. Quantum Transport.

    DTIC Science & Technology

    1994-08-15

    Notre Dame was concerned with a variety of quantum transport in mesoscopic structures. This research was funded by the Air Force Office of Scientific...Research under Grant No. AFOSR-91-0211. The major issues examined included quantum transport in high magnetic fields and modulated channels, Coulomb...lifetimes in quasi-1D structures, quantum transport experiments in metals, the mesoscopic photovoltaic effect, and new techniques for fabricating quantum structures in semiconductors.

  16. Mobile Tools | Smokefree 60+

    Cancer.gov

    These mobile resources can help you quit when you're on the go. SmokefreeTXT SmokefreeTXT is a mobile text messaging service designed for adults across the United States who are trying to quit smoking. The program offers 24/7 encouragement, advice, and tips to help smokers quit smoking and stay quit. If you are interested in signing up, fill out this form.

  17. Stem cell mobilization.

    PubMed

    Cottler-Fox, Michele H; Lapidot, Tsvee; Petit, Isabelle; Kollet, Orit; DiPersio, John F; Link, Dan; Devine, Steven

    2003-01-01

    Successful blood and marrow transplant (BMT), both autologous and allogeneic, requires the infusion of a sufficient number of hematopoietic progenitor/stem cells (HPCs) capable of homing to the marrow cavity and regenerating a full array of hematopoietic cell lineages in a timely fashion. At present, the most commonly used surrogate marker for HPCs is the cell surface marker CD34, identified in the clinical laboratory by flow cytometry. Clinical studies have shown that infusion of at least 2 x 10(6) CD34(+) cells/kg recipient body weight results in reliable engraftment as measured by recovery of adequate neutrophil and platelet counts approximately 14 days after transplant. Recruitment of HPCs from the marrow into the blood is termed mobilization, or, more commonly, stem cell mobilization. In Section I, Dr. Tsvee Lapidot and colleagues review the wide range of factors influencing stem cell mobilization. Our current understanding focuses on chemokines, proteolytic enzymes, adhesion molecules, cytokines and stromal cell-stem cell interactions. On the basis of this understanding, new approaches to mobilization have been designed and are now starting to undergo clinical testing. In Section II, Dr. Michele Cottler-Fox describes factors predicting the ability to mobilize the older patient with myeloma. In addition, clinical approaches to improving collection by individualizing the timing of apheresis and adjusting the volume of blood processed to achieve a desired product are discussed. Key to this process is the daily enumeration of blood CD34(+) cells. Newer methods of enumerating and mobilizing autologous blood HPCs are discussed. In Section III, Dr. John DiPersio and colleagues provide data on clinical results of mobilizing allogeneic donors with G-CSF, GM-CSF and the combination of both as relates to the number and type of cells collected by apheresis. Newer methods of stem cell mobilization as well as the relationship of graft composition on immune reconstitution

  18. Mobile Christian - shuttle flight

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Louis Stork, 13, and Erin Whittle, 14, look on as Brianna Johnson, 14, conducts a 'test' of a space shuttle main engine in the Test Control Center exhibit in StenniSphere, the visitor center at NASA's John C. Stennis Space Center near Bay St. Louis, Miss. The young people were part of a group from Mobile Christian School in Mobile, Ala., that visited StenniSphere on April 21.

  19. Mobile multiple access study

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Multiple access techniques (FDMA, CDMA, TDMA) for the mobile user and attempts to identify the current best technique are discussed. Traffic loading is considered as well as voice and data modulation and spacecraft and system design. Emphasis is placed on developing mobile terminal cost estimates for the selected design. In addition, design examples are presented for the alternative techniques of multiple access in order to compare with the selected technique.

  20. First-Principles Prediction of the Charge Mobility in Black Phosphorus Semiconductor Nanoribbons.

    PubMed

    Xiao, Jin; Long, Mengqiu; Zhang, Xiaojiao; Zhang, Dan; Xu, Hui; Chan, Kwok Sum

    2015-10-15

    We have investigated the electronic structure and carrier mobility of monolayer black phosphorus nanoribbons (BPNRs) using density functional theory combined with Boltzmann transport method with relaxation time approximation. It is shown that the calculated ultrahigh electron mobility can even reach the order of 10(3) to 10(7) cm(2) V(-1) s(-1) at room temperature. Owing to the electron mobility being higher than the hole mobility, armchair and diagonal BPNRs behave like n-type semiconductors. Comparing with the bare BPNRs, the difference between the hole and electronic mobilities can be enhanced in ribbons with the edges terminated by H atoms. Moreover, because the hole mobility is about two orders of magnitude larger than the electron mobility, zigzag BPNRs with H termination behave like p-type semiconductors. Our results indicate that BPNRs can be considered as a new kind of nanomaterial for applications in optoelectronics, nanoelectronic devices owing to the intrinsic band gap and ultrahigh charge mobility.

  1. Carrier mobility in rubrene-doped 4-cyano-4'-pentylbiphenyl studied by the time-of-flight method

    NASA Astrophysics Data System (ADS)

    Honma, Michinori; Nose, Toshiaki

    2013-09-01

    We have investigated the transient photocurrent of rubrene-doped nematic liquid crystal using a time-of-flight examination. Drift mobilities on the order of 10-6 cm2/V s were obtained for both positive and negative carriers. The minimal dependence of the rubrene concentration on the drift mobility is indicative of the ionic conduction as carrier transport process. The product of the drift mobility and the viscosity obeys the Walden rule, further supporting the ionic carrier transport process.

  2. Lagrangian Sediment Transport Model

    NASA Astrophysics Data System (ADS)

    Maderych, V.; Brovchenko, I.; Fenical, S.; Shepsis, V.

    2004-12-01

    A new two-dimensional Lagrangian sediment transport model was developed to simulate a wide-range of sediment transport processes, including sediment mobility under combined current and wave action, sediment transport and bed change under wave and currents effects, sediment transport patterns at nearshore coastal and offshore structures, and turbidity and sediment motion during dredging and dredged material placement. The Lagrangian technique was used to simulate transport of sediments, deposition, and re-suspension. The model can be applied to cohesive, non-cohesive, or mixed sediments. The sediment transport is simulated using bathymetry data, bed resistance characteristics, wave height and period, depth-averaged current velocity and bed material type, size and gradation, which vary throughout the model domain.The non-cohesive sediment transport model is based on a solution of two-dimensional mass conservation equations for the bed layer material and 2D equations for movement of sediment fractions either bed load or suspended load. The water column and bottom are divided into a set of layers: water layer, active layer, several active bed layers, and the bed layer. The model also takes into account the effects of armoring and changes in the bed composition. Cohesive sediments move entirely as suspended load in the water layer and sediment transport computations are based on a solution of the two-dimensional mass conservation equations for the bed layer material and two-dimensional equations for movement of sediment as suspended load. The water column and bed, as for non-cohesive sediments, was divided into a set of layers. Following the approach of Van Ledden (2002), the erosion of sediments made up of mud and sand mixtures is non-cohesive if the mud content is below a critical level. Above a critical mud content, the bed behaves cohesively. Deposition fluxes of mud and sand are independent. The sediment concentration in the water and active layer is represented by

  3. Mobility decline in old age.

    PubMed

    Rantakokko, Merja; Mänty, Minna; Rantanen, Taina

    2013-01-01

    Mobility is important for community independence. With increasing age, underlying pathologies, genetic vulnerabilities, physiological and sensory impairments, and environmental barriers increase the risk for mobility decline. Understanding how mobility declines is paramount to finding ways to promote mobility in old age.

  4. Mobile medical image retrieval

    NASA Astrophysics Data System (ADS)

    Duc, Samuel; Depeursinge, Adrien; Eggel, Ivan; Müller, Henning

    2011-03-01

    Images are an integral part of medical practice for diagnosis, treatment planning and teaching. Image retrieval has gained in importance mainly as a research domain over the past 20 years. Both textual and visual retrieval of images are essential. In the process of mobile devices becoming reliable and having a functionality equaling that of formerly desktop clients, mobile computing has gained ground and many applications have been explored. This creates a new field of mobile information search & access and in this context images can play an important role as they often allow understanding complex scenarios much quicker and easier than free text. Mobile information retrieval in general has skyrocketed over the past year with many new applications and tools being developed and all sorts of interfaces being adapted to mobile clients. This article describes constraints of an information retrieval system including visual and textual information retrieval from the medical literature of BioMedCentral and of the RSNA journals Radiology and Radiographics. Solutions for mobile data access with an example on an iPhone in a web-based environment are presented as iPhones are frequently used and the operating system is bound to become the most frequent smartphone operating system in 2011. A web-based scenario was chosen to allow for a use by other smart phone platforms such as Android as well. Constraints of small screens and navigation with touch screens are taken into account in the development of the application. A hybrid choice had to be taken to allow for taking pictures with the cell phone camera and upload them for visual similarity search as most producers of smart phones block this functionality to web applications. Mobile information access and in particular access to images can be surprisingly efficient and effective on smaller screens. Images can be read on screen much faster and relevance of documents can be identified quickly through the use of images contained in

  5. Caring for Older People. Public transport.

    PubMed Central

    Roper, T. A.; Mulley, G. P.

    1996-01-01

    Most older people are mobile and able to use public transport without any problems. Those who are hard of hearing or have poor vision and those with mobility problems need not be deterred from using public transport. Though the design and provision of suitable buses, taxis, and trains is not always optimum, many now have imaginative features to help older passengers. Travel by air and sea needs extra planning for disabled elderly people, but helpful advice is available and much can be done to enable even the most disabled traveller to make long journeys confidently and in comfort. Images p415-a Fig 1 Fig 2 Fig 3 PMID:8761236

  6. The motion commotion: Human factors in transportation

    NASA Technical Reports Server (NTRS)

    Millar, A. E., Jr. (Editor); Rosen, R. L. (Editor); Gibson, J. D. (Editor); Crum, R. G. (Editor)

    1972-01-01

    The program for a systems approach to the problem of incorporating human factors in designing transportation systems is summarized. The importance of the human side of transportation is discussed along with the three major factors related to maintaining a mobile and quality life. These factors are (1) people, as individuals and groups, (2) society as a whole, and (3) the natural environment and man-made environs. The problems and bottlenecks are presented along with approaches to their solutions through systems analysis. Specific recommendations essential to achieving improved mobility within environmental constraints are presented.

  7. DETAIL VIEW OF CONNECTOR FOR MATING TO THE CRAWLER TRANSPORTER ...

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

    DETAIL VIEW OF CONNECTOR FOR MATING TO THE CRAWLER TRANSPORTER - Cape Canaveral Air Force Station, Launch Complex 39, Mobile Launcher Platforms, Launcher Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

  8. The MSAT spacecraft of Telesat Mobile Inc.

    NASA Astrophysics Data System (ADS)

    Bertenyi, E.

    The MSAT spacecraft of the Canadian mobile satellite operator, Telesat Mobile Inc. (TMI) is described. When launched in 1994, the large geostationary MSAT spacecraft which is currently under construction by Hughes Aircraft Co. and Spar Aerospace Ltd. will enable TMI to provide mobile and transportable communications services to its customers even in the most remote parts of the North American continent. The main elements of TMI's mobile satellite system (described in a companion paper) are the space segment and the ground segment. TMI's space segment will employ one of two nearly identical satellites, one of which will be owned and operated by TMI, the other by the U.S. mobile satellite operator, American Mobile Satellite Corporation (AMSC). The two companies are participating in a joint spacecraft procurement in order to reduce the nonrecurring costs and to ensure system compatibility between the two systems; and they have also agreed to provide in-orbit backup to each other in the event of a catastrophic satellite failure. The program status, performance requirements, main parameters, and configuration of the MSAT spacecraft are reviewed. The major features of the communications subsystem are discussed in some detail, and a brief summary is presented of the spacecraft service module. Key technology items include the L-band RF power amplifier, which must operate with a high DC to RF power efficiency and generate low intermodulation when loaded with multi-carrier signals; and the large diameter deployable L-band antenna. The development status and expected performance of these spacecraft components is examined.

  9. School Transportation.

    ERIC Educational Resources Information Center

    Executive Educator, 1989

    1989-01-01

    A special report on school transportation covers the following topics: (1) a school bus safety update; (2) equipping school buses with motion detectors; (3) state training requirements for school bus drivers; (4) recruiting and retaining drivers; (5) regulations covering underground fuel-storage tanks; and (6) a transportation directory. (MLF)

  10. Transport Phenomena.

    ERIC Educational Resources Information Center

    McCready, Mark J.; Leighton, David T.

    1987-01-01

    Discusses the problems created in graduate chemical engineering programs when students enter with a wide diversity of understandings of transport phenomena. Describes a two-semester graduate transport course sequence at the University of Notre Dame which focuses on fluid mechanics and heat and mass transfer. (TW)

  11. Research and development of electric vehicles for clean transportation.

    PubMed

    Wada, Masayoshi

    2009-01-01

    This article presents the research and development of an electric vehicle (EV) in Department of Human-Robotics Saitama Institute of Technology, Japan. Electric mobile systems developed in our laboratory include a converted electric automobile, electric wheelchair and personal mobile robot. These mobile systems contribute to realize clean transportation since energy sources and devices from all vehicles, i.e., batteries and electric motors, does not deteriorate the environment. To drive motors for vehicle traveling, robotic technologies were applied.

  12. Charge-transport model for conducting polymers

    NASA Astrophysics Data System (ADS)

    Dongmin Kang, Stephen; Jeffrey Snyder, G.

    2016-11-01

    The growing technological importance of conducting polymers makes the fundamental understanding of their charge transport extremely important for materials and process design. Various hopping and mobility edge transport mechanisms have been proposed, but their experimental verification is limited to poor conductors. Now that advanced organic and polymer semiconductors have shown high conductivity approaching that of metals, the transport mechanism should be discernible by modelling the transport like a semiconductor with a transport edge and a transport parameter s. Here we analyse the electrical conductivity and Seebeck coefficient together and determine that most polymers (except possibly PEDOT:tosylate) have s = 3 and thermally activated conductivity, whereas s = 1 and itinerant conductivity is typically found in crystalline semiconductors and metals. The different transport in polymers may result from the percolation of charge carriers from conducting ordered regions through poorly conducting disordered regions, consistent with what has been expected from structural studies.

  13. Thorium mobilization in a terrestrial environment

    SciTech Connect

    Lei, W.

    1984-01-01

    The mobilization of naturally-occurring thorium from an ore body containing about 30,000 metric tons has been used to assess the potential for tetravalent plutonium transport from a deep geologic waste repository that has been eroded to the surface of the earth and breached by groundwater. Thorium mobility from the deposit was assessed due to water erosion and groundwater solubilization. The ore body is estimated to be about 60 million years old and is located, in an exposed and highly weathered condition, near the summit of a hill in the State of Minas Gerais, Brazil. Rainfall during the one year period of study (177 cm) was close to the 30 year mean of 170 cm. Most of the precipitation occurs during a four month rainy season. It was found that storm runoff yields a fractional removal rate of 10/sup -6/ yr/sup -1/ mainly by surface erosion while groundwater solubilization resulted in a removal rate of 10/sup -9/ yr/sup -1/. Thus, physical transport in surface runofff dominates by three orders of magnitude and is the primary mechanism for thorium removal from the ore body under current environmental conditions. The mean life of the thorium in the deposit is 10/sup 6/ years if controlled by rainfall erosion and 10/sup 9/ years if controlled by groundwater solubilization, respectively. Because of the improbability that a deep geologic repository will become exposed at the surface of the earth, groundwater solubilization is a more relevant mobilization mechanism than erosion.

  14. Regularity and predictability of human mobility in personal space.

    PubMed

    Austin, Daniel; Cross, Robin M; Hayes, Tamara; Kaye, Jeffrey

    2014-01-01

    Fundamental laws governing human mobility have many important applications such as forecasting and controlling epidemics or optimizing transportation systems. These mobility patterns, studied in the context of out of home activity during travel or social interactions with observations recorded from cell phone use or diffusion of money, suggest that in extra-personal space humans follow a high degree of temporal and spatial regularity - most often in the form of time-independent universal scaling laws. Here we show that mobility patterns of older individuals in their home also show a high degree of predictability and regularity, although in a different way than has been reported for out-of-home mobility. Studying a data set of almost 15 million observations from 19 adults spanning up to 5 years of unobtrusive longitudinal home activity monitoring, we find that in-home mobility is not well represented by a universal scaling law, but that significant structure (predictability and regularity) is uncovered when explicitly accounting for contextual data in a model of in-home mobility. These results suggest that human mobility in personal space is highly stereotyped, and that monitoring discontinuities in routine room-level mobility patterns may provide an opportunity to predict individual human health and functional status or detect adverse events and trends.

  15. Colloid-Facilitated Transport of Radionuclides through the Vadose Zone

    SciTech Connect

    Flury, Markus; Harsh, James B.; Zachara, John M.; McCarthy, John F.; Lichtner, Peter C.

    2006-05-31

    This project seeks to improve the basic understanding of the role of colloids in facilitating the transport of contaminants in the vadose zone. We focus on three major thrusts: (1) thermodynamic stability and mobility of colloids formed by reactions of sediments with highly alkaline tank waste solutions, (2) colloid-contaminant interactions, and (3) in-situ colloid mobilization and colloid facilitated contaminant transport occurring in both contaminated and uncontaminated Hanford sediments.

  16. The Rise of Air Mobility and Its Generals

    DTIC Science & Technology

    2008-03-01

    sorties two to one.3 “Never before in the history of warfare have so many air missions during wartime been air mobility over such an extended period.”4...Transportation Network. “ GTN gives its customers located any- where in the world a seamless, near-real-time capability to access—and em- ploy...transportation and deployment information. GTN is an automated command and control information system that supports the family of trans- portation users and

  17. Efficient Mobility Management Signalling in Network Mobility Supported PMIPV6.

    PubMed

    Samuelraj, Ananthi Jebaseeli; Jayapal, Sundararajan

    2015-01-01

    Proxy Mobile IPV6 (PMIPV6) is a network based mobility management protocol which supports node's mobility without the contribution from the respective mobile node. PMIPV6 is initially designed to support individual node mobility and it should be enhanced to support mobile network movement. NEMO-BSP is an existing protocol to support network mobility (NEMO) in PMIPV6 network. Due to the underlying differences in basic protocols, NEMO-BSP cannot be directly applied to PMIPV6 network. Mobility management signaling and data structures used for individual node's mobility should be modified to support group nodes' mobility management efficiently. Though a lot of research work is in progress to implement mobile network movement in PMIPV6, it is not yet standardized and each suffers with different shortcomings. This research work proposes modifications in NEMO-BSP and PMIPV6 to achieve NEMO support in PMIPV6. It mainly concentrates on optimizing the number and size of mobility signaling exchanged while mobile network or mobile network node changes its access point.

  18. Efficient Mobility Management Signalling in Network Mobility Supported PMIPV6

    PubMed Central

    Jebaseeli Samuelraj, Ananthi; Jayapal, Sundararajan

    2015-01-01

    Proxy Mobile IPV6 (PMIPV6) is a network based mobility management protocol which supports node's mobility without the contribution from the respective mobile node. PMIPV6 is initially designed to support individual node mobility and it should be enhanced to support mobile network movement. NEMO-BSP is an existing protocol to support network mobility (NEMO) in PMIPV6 network. Due to the underlying differences in basic protocols, NEMO-BSP cannot be directly applied to PMIPV6 network. Mobility management signaling and data structures used for individual node's mobility should be modified to support group nodes' mobility management efficiently. Though a lot of research work is in progress to implement mobile network movement in PMIPV6, it is not yet standardized and each suffers with different shortcomings. This research work proposes modifications in NEMO-BSP and PMIPV6 to achieve NEMO support in PMIPV6. It mainly concentrates on optimizing the number and size of mobility signaling exchanged while mobile network or mobile network node changes its access point. PMID:26366431

  19. Mobile propeller dynamometer validation

    NASA Astrophysics Data System (ADS)

    Morris, Mason Wade

    With growing interest in UAVs and OSU's interest in propeller performance and manufacturing, evaluating UAV propeller and propulsion system performance has become essential. In attempts to evaluate these propellers a mobile propeller dynamometer has been designed, built, and tested. The mobile dyno has been designed to be cost effective through the ability to load it into the back of a test vehicle to create simulated forward flight characteristics. This allows much larger propellers to be dynamically tested without the use of large and expensive wind tunnels. While evaluating the accuracy of the dyno, several improvements had to be made to get accurate results. The decisions made to design and improve the mobile propeller dyno will be discussed along with attempts to validate the dyno by comparing its results against known sources. Another large part of assuring the accuracy of the mobile dyno is determining if the test vehicle will influence the flow going into the propellers being tested. The flow into the propeller needs to be as smooth and uniform as possible. This is determined by characterizing the boundary layer and accelerated flow over the vehicle. This evaluation was accomplished with extensive vehicle aerodynamic measurements with the use of full-scale tests using a pitot-rake and the actual test vehicle. Additional tests were conducted in Oklahoma State University's low speed wind tunnel with a 1/8-scale model using qualitative flow visualization with smoke. Continuing research on the mobile dyno will be discussed, along with other potential uses for the dyno.

  20. Autonomous mobile communication relays

    NASA Astrophysics Data System (ADS)

    Nguyen, Hoa G.; Everett, Hobart R.; Manouk, Narek; Verma, Ambrish

    2002-07-01

    Maintaining a solid radio communication link between a mobile robot entering a building and an external base station is a well-recognized problem. Modern digital radios, while affording high bandwidth and Internet-protocol-based automatic routing capabilities, tend to operate on line-of-sight links. The communication link degrades quickly as a robot penetrates deeper into the interior of a building. This project investigates the use of mobile autonomous communication relay nodes to extend the effective range of a mobile robot exploring a complex interior environment. Each relay node is a small mobile slave robot equipped with sonar, ladar, and 802.11b radio repeater. For demonstration purposes, four Pioneer 2-DX robots are used as autonomous mobile relays, with SSC-San Diego's ROBART III acting as the lead robot. The relay robots follow the lead robot into a building and are automatically deployed at various locations to maintain a networked communication link back to the remote operator. With their on-board external sensors, they also act as rearguards to secure areas already explored by the lead robot. As the lead robot advances and RF shortcuts are detected, relay nodes that become unnecessary will be reclaimed and reused, all transparent to the operator. This project takes advantage of recent research results from several DARPA-funded tasks at various institutions in the areas of robotic simulation, ad hoc wireless networking, route planning, and navigation. This paper describes the progress of the first six months of the project.

  1. Electronic transport in smectic liquid crystals

    NASA Astrophysics Data System (ADS)

    Shiyanovskaya, I.; Singer, K. D.; Twieg, R. J.; Sukhomlinova, L.; Gettwert, V.

    2002-04-01

    Time-of-flight measurements of transient photoconductivity have revealed bipolar electronic transport in phenylnaphthalene and biphenyl liquid crystals (LC), which exhibit several smectic mesophases. In the phenylnaphthalene LC, the hole mobility is significantly higher than the electron mobility and exhibits different temperature and phase behavior. Electron mobility in the range ~10-5 cm2/V s is temperature activated and remains continuous at the phase transitions. However, hole mobility is nearly temperature independent within the smectic phases, but is very sensitive to smectic order, 10-3 cm2/V s in the smectic-B (Sm-B) and 10-4 cm2/V s in the smectic-A (Sm-A) mesophases. The different behavior for holes and electron transport is due to differing transport mechanisms. The electron mobility is apparently controlled by rate-limiting multiple shallow trapping by impurities, but hole mobility is not. To explain the lack of temperature dependence for hole mobility within the smectic phases we consider two possible polaron transport mechanisms. The first mechanism is based on the hopping of Holstein small polarons in the nonadiabatic limit. The polaron binding energy and transfer integral values, obtained from the model fit, turned out to be sensitive to the molecular order in smectic mesophases. A second possible scenario for temperature-independent hole mobility involves the competion between two different polaron mechanisms involving so-called nearly small molecular polarons and small lattice polarons. Although the extracted transfer integrals and binding energies are reasonable and consistent with the model assumptions, the limited temperature range of the various phases makes it difficult to distinguish between any of the models. In the biphenyl LCs both electron and hole mobilities exhibit temperature activated behavior in the range of 10-5 cm2/V s without sensitivity to the molecular order. The dominating transport mechanism is considered as multiple trapping

  2. Mobile Phone Terminal

    NASA Technical Reports Server (NTRS)

    1978-01-01

    In the photo, an employee of a real estate firm is contacting his office by means of HICOM, an advanced central terminal for mobile telephones. Developed by the Orlando Division of Martin Marietta Aerospace, Orlando, Florida, and manufactured by Harris Corporation's RF Division, Rochester, N.Y., HICOM upgrades service to users, provides better system management to telephone companies, and makes more efficient use of available mobile telephone channels through a computerized central control terminal. The real estate man, for example, was able to dial his office and he could also have direct-dialed a long distance number. Mobile phones in most areas not yet served by HICOM require an operator's assistance for both local and long distance calls. HICOM improves system management by automatically recording information on all calls for accurate billing, running continual performance checks on its own operation, and reporting any malfunctions to a central office.

  3. Mobility of plasmids.

    PubMed

    Smillie, Chris; Garcillán-Barcia, M Pilar; Francia, M Victoria; Rocha, Eduardo P C; de la Cruz, Fernando

    2010-09-01

    Plasmids are key vectors of horizontal gene transfer and essential genetic engineering tools. They code for genes involved in many aspects of microbial biology, including detoxication, virulence, ecological interactions, and antibiotic resistance. While many studies have decorticated the mechanisms of mobility in model plasmids, the identification and characterization of plasmid mobility from genome data are unexplored. By reviewing the available data and literature, we established a computational protocol to identify and classify conjugation and mobilization genetic modules in 1,730 plasmids. This allowed the accurate classification of proteobacterial conjugative or mobilizable systems in a combination of four mating pair formation and six relaxase families. The available evidence suggests that half of the plasmids are nonmobilizable and that half of the remaining plasmids are conjugative. Some conjugative systems are much more abundant than others and preferably associated with some clades or plasmid sizes. Most very large plasmids are nonmobilizable, with evidence of ongoing domestication into secondary chromosomes. The evolution of conjugation elements shows ancient divergence between mobility systems, with relaxases and type IV coupling proteins (T4CPs) often following separate paths from type IV secretion systems. Phylogenetic patterns of mobility proteins are consistent with the phylogeny of the host prokaryotes, suggesting that plasmid mobility is in general circumscribed within large clades. Our survey suggests the existence of unsuspected new relaxases in archaea and new conjugation systems in cyanobacteria and actinobacteria. Few genes, e.g., T4CPs, relaxases, and VirB4, are at the core of plasmid conjugation, and together with accessory genes, they have evolved into specific systems adapted to specific physiological and ecological contexts.

  4. Mobile colloid generation induced by a cementitious plume: mineral surface-charge controls on mobilization.

    PubMed

    Li, Dien; Kaplan, Daniel I; Roberts, Kimberly A; Seaman, John C

    2012-03-06

    Cementitious materials are increasingly used as engineered barriers and waste forms for radiological waste disposal. Yet their potential effect on mobile colloid generation is not well-known, especially as it may influence colloid-facilitated contaminant transport. Whereas previous papers have studied the introduction of cement colloids into sediments, this study examined the influence of cement leachate chemistry on the mobilization of colloids from a subsurface sediment collected from the Savannah River Site, USA. A sharp mobile colloid plume formed with the introduction of a cement leachate simulant. Colloid concentrations decreased to background concentrations even though the aqueous chemical conditions (pH and ionic strength) remained unchanged. Mobile colloids were mainly goethite and to a lesser extent kaolinite. The released colloids had negative surface charges and the mean particle sizes ranged primarily from 200 to 470 nm. Inherent mineralogical electrostatic forces appeared to be the controlling colloid removal mechanism in this system. In the background pH of ~6.0, goethite had a positive surface charge, whereas quartz (the dominant mineral in the immobile sediment) and kaolinite had negative surface charges. Goethite acted as a cementing agent, holding kaolinite and itself onto the quartz surfaces due to the electrostatic attraction. Once the pH of the system was elevated, as in the cementitious high pH plume front, the goethite reversed to a negative charge, along with quartz and kaolinite, then goethite and kaolinite colloids were mobilized and a sharp spike in turbidity was observed. Simulating conditions away from the cementitious source, essentially no colloids were mobilized at 1:1000 dilution of the cement leachate or when the leachate pH was ≤ 8. Extreme alkaline pH environments of cementitious leachate may change mineral surface charges, temporarily promoting the formation of mobile colloids.

  5. EFFECTS OF HUMIC SUBSTANCES ON ATTENUATION OF METALS: BIOAVAILABILITY AND MOBILITY IN SOIL

    EPA Science Inventory

    Humic substances play vastly important roles in metal behavior in a wide variety of environments. They can affect the mobility and bioavailability of metals by binding and sequestration thereby decreasing the mobility of a metal. They can also transport metals into solution or ...

  6. Developing a Framework and Priorities to Promote Mobility among Older Adults

    ERIC Educational Resources Information Center

    Anderson, Lynda A.; Slonim, Amy; Yen, Irene H.; Jones, Dina L.; Allen, Peg; Hunter, Rebecca H.; Goins, R. Turner; Leith, Katherine H.; Rosenberg, Dori; Satariano, William A.; McPhillips-Tangum, Carol

    2014-01-01

    Mobility, broadly defined as movement in all of its forms from ambulation to transportation, is critical to supporting optimal aging. This article describes two projects to develop a framework and a set of priority actions designed to promote mobility among community-dwelling older adults. Project 1 involved a concept-mapping process to solicit…

  7. Strong mobility in weakly disordered systems

    SciTech Connect

    Ben-naim, Eli; Krapivsky, Pavel

    2009-01-01

    We study transport of interacting particles in weakly disordered media. Our one-dimensional system includes (i) disorder, the hopping rate governing the movement of a particle between two neighboring lattice sites is inhomogeneous, and (ii) hard core interaction, the maximum occupancy at each site is one particle. We find that over a substantial regime, the root-mean-square displacement of a particle s grows superdiffusively with time t, {sigma}{approx}({epsilon}t){sup 2/3}, where {epsilon} is the disorder strength. Without disorder the particle displacement is subdiffusive, {sigma} {approx}t{sup 1/4}, and therefore disorder strongly enhances particle mobility. We explain this effect using scaling arguments, and verify the theoretical predictions through numerical simulations. Also, the simulations show that regardless of disorder strength, disorder leads to stronger mobility over an intermediate time regime.

  8. The Space Mobile Network

    NASA Technical Reports Server (NTRS)

    Israel, David

    2017-01-01

    The definition and development of the next generation space communications and navigation architecture is underway. The primary goals are to remove communications and navigations constraints from missions and to enable increased autonomy. The Space Mobile Network (SMN) is an architectural concept that includes new technology and operations that will provide flight systems with an similar user experience to terrestrial wireless mobile networks. This talk will describe the SMN and its proposed new features, such as Disruption Tolerant Networking (DTN), optical communications, and User Initiated Services (UIS).

  9. Land mobile communications satellite

    NASA Astrophysics Data System (ADS)

    Carnebianca, C.; Pavesi, B.; Tuozzi, A.

    1986-09-01

    The economic value and salient technical and operational characteristics of a European Land Mobile Communication Satellite (LMCS) to complement and supplement the demand for mobile services of Western European countries in the 1995 to 2005 time frames were assessed. A significant future expansion of demand for LCMS services on the part of the public is anticipated. Important augmentations of current service capabilities could be achieved by a satellite service, improving the overall system performances and/or assisting the PTT's in containing their investments in the required infrastructure. The satellite service itself could represent a profitable revenue producer.

  10. Autonomous mobile robot teams

    NASA Technical Reports Server (NTRS)

    Agah, Arvin; Bekey, George A.

    1994-01-01

    This paper describes autonomous mobile robot teams performing tasks in unstructured environments. The behavior and the intelligence of the group is distributed, and the system does not include a central command base or leader. The novel concept of the Tropism-Based Cognitive Architecture is introduced, which is used by the robots in order to produce behavior transforming their sensory information to proper action. The results of a number of simulation experiments are presented. These experiments include worlds where the robot teams must locate, decompose, and gather objects, and defend themselves against hostile predators, while navigating around stationary and mobile obstacles.

  11. Correlation ion mobility spectroscopy

    DOEpatents

    Pfeifer, Kent B.; Rohde, Steven B.

    2008-08-26

    Correlation ion mobility spectrometry (CIMS) uses gating modulation and correlation signal processing to improve IMS instrument performance. Closely spaced ion peaks can be resolved by adding discriminating codes to the gate and matched filtering for the received ion current signal, thereby improving sensitivity and resolution of an ion mobility spectrometer. CIMS can be used to improve the signal-to-noise ratio even for transient chemical samples. CIMS is especially advantageous for small geometry IMS drift tubes that can otherwise have poor resolution due to their small size.

  12. Mobile physician order entry.

    PubMed

    Ying, Alan

    2003-01-01

    Because both computerized physician order entry (CPOE) systems and mobile technologies such as handheld devices have the potential to greatly impact the industry's future, IT vendors, hospitals, and clinicians are simply merging them into a logical convergence--"CPOE on a handheld"--with an expectation of full functionality on all platforms: computer workstations, rolling laptops, tablet PCs, and handheld devices. For these trends to succeed together, however, this expectation must be revised to establish a distinct category--mobile physician order entry (MPOE)--that is different from CPOE in form, function, and implementation.

  13. Transport Phenomena.

    ERIC Educational Resources Information Center

    Shah, D. B.

    1984-01-01

    Describes a course designed to achieve a balance between exposing students to (1) advanced topics in transport phenomena, pointing out similarities and differences between three transfer processes and (2) common methods of solving differential equations. (JN)

  14. MOBILE LADLES, ATTACHED TO OVERHEAD RAILS, ARE FILLED AT EITHER ...

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

    MOBILE LADLES, ATTACHED TO OVERHEAD RAILS, ARE FILLED AT EITHER THE MALLEABLE FOUNDRY BULL LADLE OR ELECTRIC FURNACE BEFORE THEY TRANSPORT MOLTEN IRON TO MOLDS PREPARED BY DISAMATIC MOLDMAKING MACHINE OR ON ONE OF THE CONVEYORS. - Stockham Pipe & Fittings Company, Malleable Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  15. Mobile Quarantine Facility unloaded at Ellington Air Force Base, Texas

    NASA Technical Reports Server (NTRS)

    1969-01-01

    A Mobile Quarantine Facility, with the three Apollo 11 crewmen inside, is unloaded from a U.S. Air Force C141 transport at Ellington Air Force Base early Sunday after a flight from Hawaii. A large crowd was present to welcome Astronauts Neil Armstrong, Michael Collins and Edwin Aldrin Jr. back to Houston following their historic lunar landing mission.

  16. Biodegradation of PuEDTA and Impacts on Pu Mobility

    SciTech Connect

    Xun, Luying; Bolton, Harvey, Jr.

    2003-06-01

    This project is part of a major project (PI, Dr. Harvey Bolton, Jr. at PNNL) regarding plutonium mobility in the subsurface. Ethylenediaminetetraacetate (EDTA) is a common chelating agent that can increase the mobility of radionuclides and heavy metals in groundwater. Biodegradation of EDTA decreases the enhanced mobility. The overall objective is to understand how microbial degradation affects Plutonium-EDTA transport in the environment, and the specific objective of this component is to understand how microorganisms degrade EDTA. Over the past two years, significant progress has been made to the understanding on how EDTA is degraded by an EDTA-degrading bacterium BNC1. The characterization of EDTA and nitrilotriacetate (NTA) transport into BNC1 cells is summarized here. The uptake is the limiting step in EDTA and NTA degradation. The objectives of near-term research are described. We are making progress as projected in the proposal.

  17. An aeronautical mobile satellite experiment

    NASA Technical Reports Server (NTRS)

    Jedrey, T. C.; Dessouky, K. I.; Lay, N. E.

    1990-01-01

    The various activities and findings of a NASA/FAA/COMSAT/INMARSAT collaborative aeronautical mobile satellite experiment are detailed. The primary objective of the experiment was to demonstrate and evaluate an advanced digital mobile satellite terminal developed at the Jet Propulsion Laboratory under the NASA Mobile Satellite Program. The experiment was a significant milestone for NASA/JPL, since it was the first test of the mobile terminal in a true mobile satellite environment. The results were also of interest to the general mobile satellite community because of the advanced nature of the technologies employed in the terminal.

  18. Distributed Mobility Management Scheme for Mobile IPv6

    NASA Astrophysics Data System (ADS)

    Wakikawa, Ryuji; Valadon, Guillaume; Shigechika, Noriyuki; Murai, Jun

    Mobile IPv6 and Network Mobility (NEMO) have been standardized as IP extensions. While these technologies are planned to be adopted by several communities, such as the vehicle, aviation, and cellular industries, Mobile IPv6 has serious deployment issues such as scalability, protocol resilience, and redundancy. In these technologies, a special router called a home agent is introduced to support the movement of mobile nodes. This home agent introduces overlapping, inefficient routes, and becomes a single point of failure and a performance bottleneck. In this paper, a new concept for scalable and dependable mobility management scheme is proposed. Multiple home agents serve the same set of mobile nodes. The Home Agent Reliability protocol and Home Agent migration are introduced to achieve this concept. We also propose an overlay network named a Global Mobile eXchange (GMX) that efficiently handles data traffic from and to mobile nodes, and operates home agents as would an Internet eXchange Point (IXP).

  19. Carrier mobility of MoS2 nanoribbons with edge chemical modification.

    PubMed

    Xiao, Jin; Long, Mengqiu; Li, Mingjun; Li, Xinmei; Xu, Hui; Chan, Kwoksum

    2015-03-14

    We have investigated the electronic structures and carrier mobilities of MoS2 monolayer sheets and armchair nanoribbons with chemical modification using the density functional theory combined with the Boltzmann transport method with relaxation time approximation. It is shown that the hole mobility (96.62 cm(2) V(-1) s(-1)) in monolayer sheets is about twice that of the electron mobility (43.96 cm(2) V(-1) s(-1)). The charge mobilities in MoS2 armchair nanoribbons can be regulated by edge modification owing to the changing electronic structures. In pristine armchair nanoribbons, the electron and hole mobilities are about 30 cm(2) V(-1) s(-1) and 25 cm(2) V(-1) s(-1), respectively. When the edges are terminated by H or F atoms, the hole mobility will enhance obviously even 10 times that in pristine ribbons, and the electron mobility is comparable with that in MoS2 sheets.

  20. Ionic transport in passivation layered on the lithium electrode

    NASA Astrophysics Data System (ADS)

    Nimon, Eugeny S.; Churikov, Alexei V.; Shirokov, Alexander V.; Lvov, Arlen L.; Chuvashkin, Anatoly N.

    1993-04-01

    The processes of ionic transport in passivating layers on the surface of the lithium electrode in solutions based on thionyl chloride, propylene carbonate and gamma -butyrolactone have been studied by means of pulse electrochemical methods. The data obtained are quantitatively described by a model which takes into account transport of both the intrinsic mobile lithium ions of the passivating layer and lithium ions injected into the passivating layer from the electrode or from the electrolyte solution under anodic or cathodic current directions, respectively. The values of mobility and concentration of mobile lithium ions in passivating layers formed on lithium in various solutions under open-circuit conditions have been determined.

  1. NASA NDE Applications for Mobile MEMS Devices and Sensors

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Atkinson, Gary M.; Barclay, R. O.

    2008-01-01

    NASA would like new devices and sensors for performing nondestructive evaluation (NDE) of aerospace vehicles. These devices must be small in size/volume, mass, and power consumption. The devices must be autonomous and mobile so they can access the internal structures of aircraft and spacecraft and adequately monitor the structural health of these craft. The platforms must be mobile in order to transport NDE sensors for evaluating structural integrity and determining whether further investigations will be required. Microelectromechanical systems (MEMS) technology is crucial to the development of the mobile platforms and sensor systems. This paper presents NASA s needs for micro mobile platforms and MEMS sensors that will enable NDE to be performed on aerospace vehicles.

  2. Indigenization of urban mobility

    NASA Astrophysics Data System (ADS)

    Yang, Zimo; Lian, Defu; Yuan, Nicholas Jing; Xie, Xing; Rui, Yong; Zhou, Tao

    2017-03-01

    The identification of urban mobility patterns is very important for predicting and controlling spatial events. In this study, we analyzed millions of geographical check-ins crawled from a leading Chinese location-based social networking service (Jiepang.com), which contains demographic information that facilitates group-specific studies. We determined the distinct mobility patterns of natives and non-natives in all five large cities that we considered. We used a mixed method to assign different algorithms to natives and non-natives, which greatly improved the accuracy of location prediction compared with the basic algorithms. We also propose so-called indigenization coefficients to quantify the extent to which an individual behaves like a native, which depends only on their check-in behavior, rather than requiring demographic information. Surprisingly, the hybrid algorithm weighted using the indigenization coefficients outperformed a mixed algorithm that used additional demographic information, suggesting the advantage of behavioral data in characterizing individual mobility compared with the demographic information. The present location prediction algorithms can find applications in urban planning, traffic forecasting, mobile recommendation, and so on.

  3. Mobile Learning for All

    ERIC Educational Resources Information Center

    Bestwick, Angel; Campbell, John R.

    2010-01-01

    Parents and educational professionals are asking the question, "Are schools preparing students for their future lives?" Mobile technologies such as smart phones, iPods, GPS systems, iPads, and a constant stream of information drive much of people's world and work. The use of such technologies increases with each passing day. But how often do…

  4. Mathematics and Mobile Learning

    ERIC Educational Resources Information Center

    Sayed, Fayez

    2015-01-01

    The wide range of Mathematical Apps targeting different mathematical concepts and the various types of mobile devices available present a demanding and challenging problem to the teaching and learning in the field of mathematics. In an attempt to address this issue, a few Apps were selected, implemented and tested in this work. [For complete…

  5. Mobile Equipment Expands Inventory.

    ERIC Educational Resources Information Center

    McGough, Robert L.; And Others

    1978-01-01

    Describes the Mobile Equipment Modules (MEM) system in Duluth, Minnesota. MEM is a way to hold down costs and increase learning opportunities by consolidating purchases of expensive shop equipment within the school district, grouping the equipment in modules, and scheduling and moving it from school to school as needed. (MF)

  6. Developing Mobile Based Instruction

    ERIC Educational Resources Information Center

    Martin, Florence; Pastore, Raymond; Snider, Jean

    2012-01-01

    This paper describes an instructional design class's experience developing instruction for the mobile web. The class was taught at a southeastern university in the United States in a master's level computer based instruction course. Two example projects are showcased and student reflections on design issues are highlighted. Additionally,…

  7. Mobile automatic metabolic analyzer

    NASA Technical Reports Server (NTRS)

    Bynum, B. G.; Currie, J. R.

    1975-01-01

    Two flexible pipes, attached to face mask, are connected to spirometers in mobile cart. Inhaled air volume is measured as it is drawn from one spirometer, and exhaled air volume is measured as it is breathed into second spirometer. Sensor is used to monitor heartbeat rate.

  8. Spousal Mobility and Earnings

    PubMed Central

    MCKINNISH, TERRA

    2008-01-01

    An important finding in the literature on migration has been that the earnings of married women typically decrease with a move, while the earnings of married men often increase with a move, suggesting that married women are more likely to act as the “trailing spouse.” This article considers a related but largely unexplored question: what is the effect of having an occupation that is associated with frequent migration on the migration decisions of a household and on the earnings of the spouse? Further, how do these effects differ between men and women? The Public Use Microdata Sample from the 2000 U.S. decennial census is used to calculate migration rates by occupation and education. The analysis estimates the effects of these occupational mobility measures on the migration of couples and the earnings of married individuals. I find that migration rates in both the husband’s and wife’s occupations affect the household migration decision, but mobility in the husband’s occupation matters considerably more. For couples in which the husband has a college degree (regardless of the wife’s educational level), a husband’s mobility has a large, significant negative effect on his wife’s earnings, whereas a wife’s mobility has no effect on her husband’s earnings. This negative effect does not exist for college-educated wives married to non-college-educated husbands. PMID:19110900

  9. Mathematics and Mobile Learning

    ERIC Educational Resources Information Center

    White, Tobin; Martin, Lee

    2014-01-01

    This paper argues for an approach to mobile learning that leverages students' informal digital practices as resources for designing mathematics classrooms activities. We briefly describe two exploratory designs along these lines, one featuring the use of photos taken by students outside class and the other centered on their recording and…

  10. Mobile lighting apparatus

    DOEpatents

    Roe, George Michael; Klebanoff, Leonard Elliott; Rea, Gerald W; Drake, Robert A; Johnson, Terry A; Wingert, Steven John; Damberger, Thomas A; Skradski, Thomas J; Radley, Christopher James; Oros, James M; Schuttinger, Paul G; Grupp, David J; Prey, Stephen Carl

    2013-05-14

    A mobile lighting apparatus includes a portable frame such as a moveable trailer or skid having a light tower thereon. The light tower is moveable from a stowed position to a deployed position. A hydrogen-powered fuel cell is located on the portable frame to provide electrical power to an array of the energy efficient lights located on the light tower.

  11. The Uranus Mobile Robot

    DTIC Science & Technology

    1990-09-01

    Schematics 26 Wi List of Figures 1 Neptune and Pluto .. .. .. .. .. ... .. ... ... ... ... .... 2 2 Uranus...began building our first mobile robot, Pluto (see Figure 1 a). We envisioned Pluto as the ultimate indoor robot within the grasp of current technology...smooth arced trajectory while rotating about its center. This omni-directionality combined with very precise positioning would allow Pluto to easily

  12. Gridless Overtone Mobility Spectrometry

    PubMed Central

    Zucker, Steven M.; Ewing, Michael A.; Clemmer, David E.

    2013-01-01

    A novel overtone mobility spectrometry (OMS) instrument utilizing a gridless elimination mechanism and cooperative radio frequency confinement is described. The gridless elimination region uses a set of mobility-discriminating radial electric fields that are designed so that the frequency of field application results in selective transmission and elimination of ions. To neutralize ions with mobilities that do not match the field application frequency, active elimination regions radially defocus ions towards the lens walls. Concomitantly, a lens-dependent radio frequency waveform is applied to the transmission regions of the drift tube resulting in radial confinement for mobility-matched ions. Compared with prior techniques, which use many grids for ion elimination, the new gridless configuration substantially reduces indiscriminate ion losses. A description of the apparatus and elimination process, including detailed simulations showing how ions are transmitted and eliminated is presented. A prototype 28 cm long OMS instrument is shown to have a resolving power of 20 and is capable of attomole detection limits of a model peptide (angiotensin I) spiked into a complex mixture (in this case peptides generated from digestion of β-casein with trypsin). PMID:24125033

  13. ORION mobile unit design

    NASA Technical Reports Server (NTRS)

    Brunn, D. L.; Wu, S. C.; Thom, E. H.; Mclaughlin, F. D.; Sweetser, B. M.

    1980-01-01

    An overview of the design of the ORION mobile system is presented. System capability and performance characteristics are outlined. Functional requirements and key performance parameters are stated for each of the nine subsystems. A master design and implementation schedule is given.

  14. Mobile Applications for Extension

    ERIC Educational Resources Information Center

    Drill, Sabrina L.

    2012-01-01

    Mobile computing devices (smart phones, tablets, etc.) are rapidly becoming the dominant means of communication worldwide and are increasingly being used for scientific investigation. This technology can further our Extension mission by increasing our power for data collection, information dissemination, and informed decision-making. Mobile…

  15. Autonomous mobile robot

    SciTech Connect

    Mattaboni, P.J.

    1987-01-20

    This patent describes a mobile robot of the type having (a) a vision system, (b) memory means for storing data derived from the robot vision system, and (c) a computer for processing data derived from the robot's vision system, the improvement wherein the robot's vision system comprises (i) a first array of ranging transducers for obtaining data on the position and distance of far objects in a volume of space, the transducers of the first array being symmetrically disposed on the mobile robot with respect to an axis of symmetry within the mobile robot. Each transducer of the first array is fixed in position with respect to that axis of symmetry and sees a portion of the volume of space seen by its entire array; (ii) a second array of ranging transducers for obtaining data of the position and distance of near objects in the same or an overlapping volume of space, the transducers of the second array being symmetrically disposed on the mobile robot with respect to the axis of symmetry. Each transducer of the second array is fixed in position with respect to the axis of symmetry and sees a portion of the volume of space seen by its entire array, the angle of view of the transducers of the second array being different from the angle of view of the transducers of the first array with respect to the same object in space; and (iii) means for polling the ranging transducers in sequences determined by the computer.

  16. Mobile PET Center Project

    NASA Astrophysics Data System (ADS)

    Ryzhikova, O.; Naumov, N.; Sergienko, V.; Kostylev, V.

    2017-01-01

    Positron emission tomography is the most promising technology to monitor cancer and heart disease treatment. Stationary PET center requires substantial financial resources and time for construction and equipping. The developed mobile solution will allow introducing PET technology quickly without major investments.

  17. A Mobile Education

    ERIC Educational Resources Information Center

    Schaffhauser, Dian

    2011-01-01

    Since 2008, when iStanford stormed onto the college scene as the first campus mobile app, schools from Amarillo College (Texas) to Vanderbilt University (Tennessee) have rushed to create their own offerings. Some have elected to do the work in-house; others have licensed the software from a vendor. Still others hope to bottle the same magic that…

  18. The Mobile Costume Shop.

    ERIC Educational Resources Information Center

    Witherspoon, Cindy; Nelson, Steve

    1998-01-01

    Discusses the difficulties of costume construction for high school theater productions. Advances a plan (and provides a design) for a mobile costume shop which contains the basic needs of a functional costume facility, using only 60 square feet of space. Lists every element and implement needed. (PA)

  19. Transport impacts on atmosphere and climate: Land transport

    NASA Astrophysics Data System (ADS)

    Uherek, Elmar; Halenka, Tomas; Borken-Kleefeld, Jens; Balkanski, Yves; Berntsen, Terje; Borrego, Carlos; Gauss, Michael; Hoor, Peter; Juda-Rezler, Katarzyna; Lelieveld, Jos; Melas, Dimitrios; Rypdal, Kristin; Schmid, Stephan

    2010-12-01

    Emissions from land transport, and from road transport in particular, have significant impacts on the atmosphere and on climate change. This assessment gives an overview of past, present and future emissions from land transport, of their impacts on the atmospheric composition and air quality, on human health and climate change and on options for mitigation. In the past vehicle exhaust emission control has successfully reduced emissions of nitrogen oxides, carbon monoxide, volatile organic compounds and particulate matter. This contributed to improved air quality and reduced health impacts in industrialised countries. In developing countries however, pollutant emissions have been growing strongly, adversely affecting many populations. In addition, ozone and particulate matter change the radiative balance and hence contribute to global warming on shorter time scales. Latest knowledge on the magnitude of land transport's impact on global warming is reviewed here. In the future, road transport's emissions of these pollutants are expected to stagnate and then decrease globally. This will then help to improve the air quality notably in developing countries. On the contrary, emissions of carbon dioxide and of halocarbons from mobile air conditioners have been globally increasing and are further expected to grow. Consequently, road transport's impact on climate is gaining in importance. The expected efficiency improvements of vehicles and the introduction of biofuels will not be sufficient to offset the expected strong growth in both, passenger and freight transportation. Technical measures could offer a significant reduction potential, but strong interventions would be needed as markets do not initiate the necessary changes. Further reductions would need a resolute expansion of low-carbon fuels, a tripling of vehicle fuel efficiency and a stagnation in absolute transport volumes. Land transport will remain a key sector in climate change mitigation during the next decades.

  20. Mobility platform coupling device and method for coupling mobility platforms

    DOEpatents

    Shirey, David L.; Hayward, David R.; Buttz, James H.

    2002-01-01

    A coupling device for connecting a first mobility platform to a second mobility platform in tandem. An example mobility platform is a robot. The coupling device has a loose link mode for normal steering conditions and a locking position, tight link mode for navigation across difficult terrain and across obstacles, for traversing chasms, and for navigating with a reduced footprint in tight steering conditions.

  1. The interfacility transport of critically ill newborns.

    PubMed

    Whyte, Hilary Ea; Jefferies, Ann L

    2015-01-01

    The practice of paediatric/neonatal interfacility transport continues to expand. Transport teams have evolved into mobile intensive care units capable of delivering state-of-the-art critical care during paediatric and neonatal transport. While outcomes are best for high-risk infants born in a tertiary care setting, high-risk mothers often cannot be safely transferred. Their newborns may then have to be transported to a higher level of care following birth. The present statement reviews issues relating to transport of the critically ill newborn population, including personnel, team competencies, skills, equipment, systems and processes. Six recommendations for improving interfacility transport of critically ill newborns are highlighted, emphasizing the importance of regionalized care for newborns.

  2. Brownian motion: Absolute negative particle mobility

    NASA Astrophysics Data System (ADS)

    Ros, Alexandra; Eichhorn, Ralf; Regtmeier, Jan; Duong, Thanh Tu; Reimann, Peter; Anselmetti, Dario

    2005-08-01

    Noise effects in technological applications, far from being a nuisance, can be exploited with advantage - for example, unavoidable thermal fluctuations have found application in the transport and sorting of colloidal particles and biomolecules. Here we use a microfluidic system to demonstrate a paradoxical migration mechanism in which particles always move in a direction opposite to the net acting force (`absolute negative mobility') as a result of an interplay between thermal noise, a periodic and symmetric microstructure, and a biased alternating-current electric field. This counterintuitive phenomenon could be used for bioanalytical purposes, for example in the separation and fractionation of colloids, biological molecules and cells.

  3. Arbitrary segments of absolute negative mobility

    NASA Astrophysics Data System (ADS)

    Chen, Ruyin; Nie, Linru; Chen, Chongyang; Wang, Chaojie

    2017-01-01

    In previous research work, investigators have reported only one or two segments of absolute negative mobility (ANM) in a periodic potential. In fact, many segments of ANM also occur in the system considered here. We investigate transport of an inertial particle in a gating ratchet periodic potential subjected to a constant bias force. Our numerical results show that its mean velocity can decrease with the bias force increasing, i.e. ANM phenomenon. Furthermore, the ANM can take place arbitrary segments, even up to more than thirty. Intrinsic physical mechanism and conditions for arbitrary segments of ANM to occur are discussed in detail.

  4. A mobile apparatus for solar collector testing

    NASA Technical Reports Server (NTRS)

    Hotchkiss, G. B.; Simon, F. F.; Burmeister, L. C.

    1979-01-01

    The design, construction, and operation of a mobile apparatus for solar collector testing (MASCOT) is described. The MASCOT is a self-contained test unit costing about $10,000 whose only external requirement for operation is electrical power and which is capable of testing two water-cooled flat-plate solar collectors simultaneously. The MASCOT is small enough and light enough to be transported to any geographical site for outdoor tests at the location of collector usage. It has been used in both indoor solar simulator tests and outdoor tests.

  5. STS-82 Crack on Mobile Launch Platform

    NASA Technical Reports Server (NTRS)

    1997-01-01

    After leaving the Vehicle Assembly Building, the Space Shuttle Discovery makes its slow -- up to 1 mile per hour -- trek along the Crawlerway to Launch Pad 39A in preparation for the STS-82 mission. The Shuttle is assembled on a Mobile Launch Platform (MLP), seen in this view taken from above, and the entire assemblage is carried out to the launch pad on the Crawler Transporter, which is underneath the MLP. A seven-member crew will perform the second servicing of the orbiting Hubble Space Telescope (HST) during the 10-day STS-82 mission, which is targeted for a Feb. 11 liftoff.

  6. BIOMETHYLATION AND ENVIRONMENTAL TRANSPORT OF METALS

    EPA Science Inventory

    Toxic heavy metals are ubiquitous in the environment. They are found as metal or oxide dust in air, metal ions attached to humic substances in surface and ground water, and as metal ions bound to soils and sediments. The transformations, mobilization, transport, and bioaccumulati...

  7. Social Mobility and Social Participation

    ERIC Educational Resources Information Center

    Sewell, William H.

    1978-01-01

    Examines data related to social mobility and social participation of Americans. Topics include educational and occupational mobility; voting; volunteer work; charitable giving; community participation; views on religion; and anomie. For journal availability, see SO 506 144. (Author/DB)

  8. Advanced extravehicular mobility unit study

    NASA Technical Reports Server (NTRS)

    Elkins, W.

    1982-01-01

    Components of the advanced extravehicular mobility unit (suit) are described. Design considerations for radiation protection, extravehicular operational pressure, mobility effects, tool/glove/effector, anthropometric definition, lighting, and equipment turnaround are addressed.

  9. Incorporating Mobile Phone Technologies to Expand Evidence-Based Care.

    PubMed

    Jones, Deborah J; Anton, Margaret; Gonzalez, Michelle; Honeycutt, Amanda; Khavjou, Olga; Forehand, Rex; Parent, Justin

    2015-08-01

    Ownership of mobile phones is on the rise, a trend in uptake that transcends age, region, race, and ethnicity, as well as income. It is precisely the emerging ubiquity of mobile phones that has sparked enthusiasm regarding their capacity to increase the reach and impact of health care, including mental health care. Community-based clinicians charged with transporting evidence-based interventions beyond research and training clinics are in turn, ideally and uniquely situated to capitalize on mobile phone uptake and functionality to bridge the efficacy to effectiveness gap. As such, this article delineates key considerations to guide these frontline clinicians in mobile phone-enhanced clinical practice, including an overview of industry data on the uptake of and evolution in the functionality of mobile phone platforms, conceptual considerations relevant to the integration of mobile phones into practice, representative empirical illustrations of mobile-phone enhanced assessment and treatment, and practical considerations relevant to ensuring the feasibility and sustainability of such an approach.

  10. Incorporating Mobile Phone Technologies to Expand Evidence-Based Care

    PubMed Central

    Jones, Deborah J.; Anton, Margaret; Gonzalez, Michelle; Honeycutt, Amanda; Khavjou, Olga; Forehand, Rex; Parent, Justin

    2014-01-01

    Ownership of mobile phones is on the rise, a trend in uptake that transcends age, region, race, and ethnicity, as well as income. It is precisely the emerging ubiquity of mobile phones that has sparked enthusiasm regarding their capacity to increase the reach and impact of health care, including mental health care. Community-based clinicians charged with transporting evidence-based interventions beyond research and training clinics are in turn, ideally and uniquely situated to capitalize on mobile phone uptake and functionality to bridge the efficacy to effectiveness gap. As such, this article delineates key considerations to guide these frontline clinicians in mobile phone-enhanced clinical practice, including an overview of industry data on the uptake of and evolution in the functionality of mobile phone platforms, conceptual considerations relevant to the integration of mobile phones into practice, representative empirical illustrations of mobile-phone enhanced assessment and treatment, and practical considerations relevant to ensuring the feasibility and sustainability of such an approach. PMID:26213458

  11. Libraries and the Mobile Revolution

    ERIC Educational Resources Information Center

    Krishnan, Yvonne

    2011-01-01

    With the advent of mobile phones--and smartphones in particular--people are slowly moving away from the notion that mobile phones are just for making calls and texting. This coupled with the fact that the uptake of mobile phones hit the 5 billion mark in 2010 has spurred many libraries to offer services that can be used by their patrons on these…

  12. Mobile satellite service for Canada

    NASA Technical Reports Server (NTRS)

    Sward, David

    1988-01-01

    The Mobile Satellite (MSAT) system and a special program designed to provide interim mobile satellite services (IMSS) during the construction phase of MSAT are described. A mobile satellite system is a key element in extending voice and and data telecommunications to all Canadians.

  13. Mobile Learning in Higher Education

    ERIC Educational Resources Information Center

    Fraga, Lucretia M.

    2012-01-01

    This mixed method research study investigated the beliefs of university faculty regarding mobile learning. As well as to determine if providing technology professional development to university faculty supports the increase of mobile learning opportunities in higher education. This study used the Beliefs About Mobile Learning Inventory (BAMLI) to…

  14. Long range hopping mobility platform.

    SciTech Connect

    Spletzer, Barry Louis; Fischer, Gary John

    2003-03-01

    Sandia National Laboratories has developed a mesoscale hopping mobility platform (Hopper) to overcome the longstanding problems of mobility and power in small scale unmanned vehicles. The system provides mobility in situations such as negotiating tall obstacles and rough terrain that are prohibitive for other small ground base vehicles. The Defense Advanced Research Projects Administration (DARPA) provided the funding for the hopper project.

  15. Mobile Technology in Educational Services

    ERIC Educational Resources Information Center

    Chen, Jueming; Kinshuk

    2005-01-01

    The use of computers and the Internet has successfully enabled educational institutions to provide their students and staff members with various online educational services. With the recent developments in mobile technology, further possibilities are emerging to provide such services through mobile devices such as mobile phones and PDAs. By…

  16. Public Transport for Everyone: A Summary of the Results of Research and Development Projects Concerning Disabled People and Transport Facilities Supported by the Swedish Transport Research Board. TFB-Report 1989:1.

    ERIC Educational Resources Information Center

    Borjesson, Mats

    This report summarizes the results of research and development concerning disabled individuals in Sweden and their use of transport facilities. The first section, "People with Impaired Mobility and Their Travel Needs," outlines Sweden's transport policy goal to adapt transport to the needs of disabled people, addresses the difficulty in…

  17. Self mobile space manipulator project

    NASA Technical Reports Server (NTRS)

    Brown, H. Ben; Friedman, Mark; Xu, Yangsheng; Kanade, Takeo

    1992-01-01

    A relatively simple, modular, low mass, low cost robot is being developed for space EVA that is large enough to be independently mobile on a space station or platform exterior, yet versatile enough to accomplish many vital tasks. The robot comprises two long flexible links connected by a rotary joint, with 2-DOF 'wrist' joints and grippers at each end. It walks by gripping pre-positioned attachment points, such as trusswork nodes, and alternately shifting its base of support from one foot (gripper) to the other. The robot can perform useful tasks such as visual inspection, material transport, and light assembly by manipulating objects with one gripper, while stabilizing itself with the other. At SOAR '90, we reported development of 1/3 scale robot hardware, modular trusswork to serve as a locomotion substrate, and a gravity compensation system to allow laboratory tests of locomotion strategies on the horizontal face of the trusswork. In this paper, we report on project progress including the development of: (1) adaptive control for automatic adjustment to loads; (2) enhanced manipulation capabilities; (3) machine vision, including the use of neural nets, to guide autonomous locomotion; (4) locomotion between orthogonal trusswork faces; and (5) improved facilities for gravity compensation and telerobotic control.

  18. Mobile Multicast in Hierarchical Proxy Mobile IPV6

    NASA Astrophysics Data System (ADS)

    Hafizah Mohd Aman, Azana; Hashim, Aisha Hassan A.; Mustafa, Amin; Abdullah, Khaizuran

    2013-12-01

    Mobile Internet Protocol Version 6 (MIPv6) environments have been developing very rapidly. Many challenges arise with the fast progress of MIPv6 technologies and its environment. Therefore the importance of improving the existing architecture and operations increases. One of the many challenges which need to be addressed is the need for performance improvement to support mobile multicast. Numerous approaches have been proposed to improve mobile multicast performance. This includes Context Transfer Protocol (CXTP), Hierarchical Mobile IPv6 (HMIPv6), Fast Mobile IPv6 (FMIPv6) and Proxy Mobile IPv6 (PMIPv6). This document describes multicast context transfer in hierarchical proxy mobile IPv6 (H-PMIPv6) to provide better multicasting performance in PMIPv6 domain.

  19. Seed storage oil mobilization.

    PubMed

    Graham, Ian A

    2008-01-01

    Storage oil mobilization starts with the onset of seed germination. Oil bodies packed with triacylglycerol (TAG) exist in close proximity with glyoxysomes, the single membrane-bound organelles that house most of the biochemical machinery required to convert fatty acids derived from TAG to 4-carbon compounds. The 4-carbon compounds in turn are converted to soluble sugars that are used to fuel seedling growth. Biochemical analysis over the last 50 years has identified the main pathways involved in this process, including beta-oxidation, the glyoxylate cycle, and gluconeogenesis. In the last few years molecular genetic dissection of the overall process in the model oilseed species Arabidopsis has provided new insight into its complexity, particularly with respect to the specific role played by individual enzymatic steps and the subcellular compartmentalization of the glyoxylate cycle. Both abscisic acid (ABA) and sugars inhibit storage oil mobilization and a substantial degree of the control appears to operate at the transcriptional level.

  20. Mobile Biomass Pelletizing System

    SciTech Connect

    Thomas Mason

    2009-04-16

    This grant project examines multiple aspects of the pelletizing process to determine the feasibility of pelletizing biomass using a mobile form factor system. These aspects are: the automatic adjustment of the die height in a rotary-style pellet mill, the construction of the die head to allow the use of ceramic materials for extreme wear, integrating a heat exchanger network into the entire process from drying to cooling, the use of superheated steam for adjusting the moisture content to optimum, the economics of using diesel power to operate the system; a break-even analysis of estimated fixed operating costs vs. tons per hour capacity. Initial development work has created a viable mechanical model. The overall analysis of this model suggests that pelletizing can be economically done using a mobile platform.

  1. Mobile Autonomous Humanoid Assistant

    NASA Technical Reports Server (NTRS)

    Diftler, M. A.; Ambrose, R. O.; Tyree, K. S.; Goza, S. M.; Huber, E. L.

    2004-01-01

    A mobile autonomous humanoid robot is assisting human co-workers at the Johnson Space Center with tool handling tasks. This robot combines the upper body of the National Aeronautics and Space Administration (NASA)/Defense Advanced Research Projects Agency (DARPA) Robonaut system with a Segway(TradeMark) Robotic Mobility Platform yielding a dexterous, maneuverable humanoid perfect for aiding human co-workers in a range of environments. This system uses stereo vision to locate human team mates and tools and a navigation system that uses laser range and vision data to follow humans while avoiding obstacles. Tactile sensors provide information to grasping algorithms for efficient tool exchanges. The autonomous architecture utilizes these pre-programmed skills to form human assistant behaviors. The initial behavior demonstrates a robust capability to assist a human by acquiring a tool from a remotely located individual and then following the human in a cluttered environment with the tool for future use.

  2. SIMON: Integration of mobility and parking solutions for people with disabilities.

    PubMed

    Ferreras, Alberto; Barberà, Ricard; Durá-Gil, Juan Vicente; Solaz, José; Muñoz, Eva María; Serrano, Manuel; Marqués, Antonio

    2015-01-01

    Mobility and parking in urban areas are often difficult for people with disabilities. Obstacles include lack of accessible information on routes, transport alternatives and parking availability, as well as fraud in the use of the specific services intended for these citizens. The SIMON project aims to improve this situation through the integration of different ICT solutions. SIMON is enhancing the European Parking Card for disable people with contactless technologies and integrates mobile solutions to support user unique identification in existing parking areas whilst preserving privacy. SIMON will also promote better mobility solutions for mobility including information, navigation and access to restricted areas.

  3. Empirical electron cross-field mobility in a Hall effect thruster

    SciTech Connect

    Garrigues, L.; Perez-Luna, J.; Lo, J.; Hagelaar, G. J. M.; Boeuf, J. P.; Mazouffre, S.

    2009-10-05

    Electron transport across the magnetic field in Hall effect thrusters is still an open question. Models have so far assumed 1/B{sup 2} or 1/B scaling laws for the 'anomalous' electron mobility, adjusted to reproduce the integrated performance parameters of the thruster. We show that models based on such mobility laws predict very different ion velocity distribution functions (IVDF) than measured by laser induced fluorescence (LIF). A fixed spatial mobility profile, obtained by analysis of improved LIF measurements, leads to much better model predictions of thruster performance and IVDF than 1/B{sup 2} or 1/B mobility laws for discharge voltages in the 500-700 V range.

  4. Enhancing the Electron Mobility via Delta-Doping in SrTiO3

    SciTech Connect

    Kozuka, Y.

    2011-08-11

    We fabricated high-mobility {delta}-doped structures in SrTiO{sub 3} thin films in order to investigate the low temperature electronic transport properties of confined carriers in this system. An enhancement of the electron mobility above the bulk value was observed as the doped layer thickness decreased. High-field Hall measurements revealed that this mobility enhancement originates from higher-mobility electrons in the undoped clean regions, which have quantum-mechanically broadened from the doped layer. Because of the absence of apparent lattice misfit between the layers, this structure is highly suitable for investigating two-dimensional electron gases in SrTiO{sub 3}

  5. Choices for Mobility Independence: Transportation Options for Older Adults

    MedlinePlus

    ... a minimal cost. n n Paratransit Service: Public transit, aging organizations, and private agencies provide door-to- ... is available in your area. n n Public Transit/Fixed Route Service: Public transit agencies provide bus ...

  6. [Air transport biomechanical risk: reduced mobility passengers' handling].

    PubMed

    Draicchio, F; Campoli, G; Silvetti, A; Badellino, E; Forzano, F; Ranavolo, A; Iavicoli, S; Campagna, G; Raffaele, G; Gismondi, M

    2012-01-01

    As the airport traffic increases there is a continuous increase of passengers with different motor disabilities. Disabled passenger's assistance causes a biomechanical overload in airport workers. Some disabled passengers are classified by IATA as WCHC (wheel chair in cabin or Charlie). Our study, was performed in one of the most important Italian airport on Charlie passengers (about 10% of all assistances). We identified four critical points: 1) wheelchair and baggage moving (unstable load), 2) inclined ramps with worker's backwards steps and braked wheelchair to prevent passenger tipping or falling, 3) transfer from standard wheelchair to bicycle wheelchair, specifically designed for the aisle; 4.) transfer from bicycle wheelchair to aircraft seat. The last two points required sometimes to lift passengers over the armrest and positioning them on a window side seat, causing a serious increase of biomechanical load. For each critical point we have proposed technical and organizational measures to reduce airport worker's biomechanical risk.

  7. Senior Transportation and Mobility Improvement Act of 2011

    THOMAS, 112th Congress

    Sen. Kohl, Herb [D-WI

    2011-12-05

    12/05/2011 Read twice and referred to the Committee on Banking, Housing, and Urban Affairs. (text of measure as introduced: CR S8184-8185) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  8. Miniaturized Ion Mobility Spectrometer

    NASA Technical Reports Server (NTRS)

    Kaye, William J. (Inventor); Stimac, Robert M. (Inventor)

    2015-01-01

    By utilizing the combination of a unique electronic ion injection control circuit in conjunction with a particularly designed drift cell construction, the instantly disclosed ion mobility spectrometer achieves increased levels of sensitivity, while achieving significant reductions in size and weight. The instant IMS is of a much simpler and easy to manufacture design, rugged and hermetically sealed, capable of operation at high temperatures to at least 250.degree. C., and is uniquely sensitive, particularly to explosive chemicals.

  9. Corps Mobilization Posture.

    DTIC Science & Technology

    1980-02-01

    lation. The " one - stop " service concept is fundamental among these elements. Despite what the Corps’ internal structure may be, external customers (e.g...34 one - stop " service dictates that there be a total vertical and lateral communi- cations network between the lead district and all elements that must...should approve the " one - stop " service concept for application to advance mobilization planning and execution. b. COE should approve the concept of MC

  10. Mobile Data Access

    DTIC Science & Technology

    1998-05-11

    F19628-93-C-0193, the Intel Corporation, the National Science Foundation, AT&T, and Lucent Technologies . The views and conclusions contained herein...in other locations must resort to some alternative wireless technology ; moving between these technologies yields significant variation. There is one...supporting infrastructure, and poor security and robustness, are inherent to mobile systems and will not be ehminated by technological progress. The

  11. Air transport

    NASA Technical Reports Server (NTRS)

    Page, F Handley

    1924-01-01

    I purpose (sic) in this paper to deal with the development in air transport which has taken place since civil aviation between England and the Continent first started at the end of August 1919. A great deal of attention has been paid in the press to air services of the future, to the detriment of the consideration of results obtained up to the present.

  12. Pupil Transportation.

    ERIC Educational Resources Information Center

    Bete, Tim, Ed.

    1998-01-01

    Presents the opinions of four transportation experts on issues related to school buses. The experts respond to the following questions: will advertisements placed on buses be used to generate district revenue; will compressed natural gas or liquefied natural gas become standard fuel for school buses; and will school bus seat belts be mandatory and…

  13. Anomalous transport

    NASA Astrophysics Data System (ADS)

    Cheverry, Christophe

    2017-02-01

    This article is concerned with the relativistic Vlasov equation, for collisionless axisymmetric plasmas immersed in a strong magnetic field, like in tokamaks. It provides a consistent kinetic treatment of the microscopic particle phase-space dynamics. It shows that the turbulent transport can be completely described through WKB expansions.

  14. Electrophoretic Transport of Biomolecules through Carbon Nanotube Membranes

    PubMed Central

    Sun, Xinghua; Su, Xin; Wu, Ji; Hinds, Bruce J.

    2013-01-01

    Electrophoretic transport of proteins across electrochemically oxidized multi-walled carbon nanotube (MWCNT) membranes has been investigated. Small charged protein, lysozyme, was successfully pumped across MWCNT membranes by electric field while rejecting larger bovine serum albumin (BSA). Transport of the lysozome was reduced by a factor of about 30 in comparison to bulk mobility and consistent with prediction for hindered transport. Mobilities between 0.33-1.4×10-9 m2/V-s were observed and are approximately 10 fold faster than comparable ordered nanoporous membranes and are consistent with continuum models. For mixtures of BSA and lysozyme, complete rejection of BSA is seen with electrophoretic separations PMID:21338104

  15. High-mobility diamond

    NASA Astrophysics Data System (ADS)

    Landstrass, Maurice I.

    1994-04-01

    Recent improvements in the CVD diamond deposition process have made possible the fabrication of diamond photoconductive diodes with carrier mobility and lifetime exceeding the values typical of natural gemstones. One of the more surprising recent results is that the best room-temperature carrier properties have been measured on polycrystalline diamond films. The combined electron- hole mobility, as measured by transient photoconductivity at low carrier densities, is 4000 square centimeters per volt per second at electric field of 200 volts per centimeter and is comparable to that of the best single-crystal IIa natural diamonds. Carrier lifetimes measured under the same conditions are 150 picoseconds for the CVD diamond films. The collection distance within the diamond films, at the highest applied fields, is comparable to the average film grain size, indicative of little or no carrier scattering at grain boundaries. A comparison of SIMS measurements with electrical results suggest that impurity incorporation in the near grain boundary regions are responsible for controlling the carrier mobility.

  16. Mobile EEG in epilepsy.

    PubMed

    Askamp, Jessica; van Putten, Michel J A M

    2014-01-01

    The sensitivity of routine EEG recordings for interictal epileptiform discharges in epilepsy is limited. In some patients, inpatient video-EEG may be performed to increase the likelihood of finding abnormalities. Although many agree that home EEG recordings may provide a cost-effective alternative to these recordings, their use is still not introduced everywhere. We surveyed Dutch neurologists and patients and evaluated a novel mobile EEG device (Mobita, TMSi). Key specifications were compared with three other current mobile EEG devices. We shortly discuss algorithms to assist in the review process. Thirty percent (33 out of 109) of Dutch neurologists reported that home EEG recordings are used in their hospital. The majority of neurologists think that mobile EEG can have additional value in investigation of unclear paroxysms, but not in the initial diagnosis after a first seizure. Poor electrode contacts and signal quality, limited recording time and absence of software for reliable and effective assistance in the interpretation of EEGs have been important constraints for usage, but in recent devices discussed here, many of these problems have been solved. The majority of our patients were satisfied with the home EEG procedure and did not think that our EEG device was uncomfortable to wear, but they did feel uneasy wearing it in public.

  17. Networking a mobile robot

    NASA Astrophysics Data System (ADS)

    McKee, Gerard T.

    1994-10-01

    Conventional mobile robotic systems are `stand alone'. Program development involves loading programs into the mobile, via an umbilical. Autonomous operation, in this context, means `isolation': the user cannot interact with the program as the robot is moving around. Recent research in `swarm robotics' has exploited wireless networks as a means of providing inter- robot communication, but the population is still isolated from the human user. In this paper we report on research we are conducting into the provision of mobile robots as resources on a local area computer network, and thus breaking the isolation barrier. We are making use of new multimedia workstation and wireless networking technology to link the robots to the network in order to provide a new type of resource for the user. We model the robot as a set of resources and propose a client-server architecture as the basis for providing user access to the robots. We describe the types of resources each robot can provide and we outline the potential for cooperative robotics, human-robot cooperation, and teleoperation and autonomous robot behavior within this context.

  18. A test of a climatic index of dune mobility using measurements from the southwestern United States

    USGS Publications Warehouse

    Lancaster, N.; Helm, P.

    2000-01-01

    The climatic index of dune mobility developed by Lancaster (1988) has been applied to a variety of different environments. The index is, however, untested and unverified. We tested the index by comparison of values of the dune mobility index calculated from climate data with rates of sand transport measured at three stations in Arizona and New Mexico over the period 1985 to 1997. Our results show that changes in measured rates of sand transport closely parallel temporal changes in the dune mobility index. The mobility index is, however, a relatively poor predictor of the magnitude of actual sand transport on a year-to-year basis. This discrepancy is probably due to the fact that sand transport rates at these sites are strongly influenced by vegetation cover, the state of which may lag changes in annual precipitation. There is, however, a good relation between the mean annual mobility index and mean annual rates of sand transport. This indicates that the dune mobility index is a valid predictor of the long-term state of the aeolian system and can be used confidently for the purposes for which it was originally intended. Copyright (C) 2000 John Wiley and Sons, Ltd.

  19. Advantage of suppressed non-Langevin recombination in low mobility organic solar cells

    SciTech Connect

    Stolterfoht, Martin; Armin, Ardalan; Pandey, Ajay K.; Burn, Paul L.; Meredith, Paul; Pivrikas, Almantas; Philippa, Bronson; White, Ronald D.

    2014-07-07

    Photovoltaic performance in relation to charge transport is studied in efficient (7.6%) organic solar cells (PTB7:PC{sub 71}BM). Both electron and hole mobilities are experimentally measured in efficient solar cells using the resistance dependent photovoltage technique, while the inapplicability of classical techniques, such as space charge limited current and photogenerated charge extraction by linearly increasing voltage is discussed. Limits in the short-circuit current originate from optical losses, while charge transport is shown not to be a limiting process. Efficient charge extraction without recombination can be achieved with a mobility of charge carriers much lower than previously expected. The presence of dispersive transport with strongly distributed mobilities in high efficiency solar cells is demonstrated. Reduced non-Langevin recombination is shown to be beneficial for solar cells with imbalanced, low, and dispersive electron and hole mobilities.

  20. Studies on deaf mobile application

    NASA Astrophysics Data System (ADS)

    Nathan, Shelena Soosay; Hussain, Azham; Hashim, Nor Laily

    2016-08-01

    The deaf normally considered to be disabled that do not need any mobile technology due to the inabilities of hearing and talking. However, many deaf are using mobile phone in their daily life for various purposes such as communication and learning. Many studies have attempted to identify the need of deaf people in mobile application and level of usage of the applications. This study aims in studying the recent research conducted on deaf mobile application to understand the level of importance of mobile technology for this disabled community. This paper enable identification of studies conducted are limited and the need of more research done of this disabled people to ensure their privilege of using mobile technology and its application, which leads to the identification of deaf user requirement for mobile application as future study.

  1. Mobile visual examination and repackaging (MOVER) system

    SciTech Connect

    Los Alamos National Laboratory

    2001-01-01

    Process engineering and waste technology teams at LOS Alamos National Laboratory delivered a prototype Mobile Visual Examination and Repackaging (MOVER) system to the Waste Isolation Pilot Plant (WIPP) outside of Carlsbad, NM in October, 2000. This system was developed in response to compliance issues with legacy waste that was packaged in 55 gallons drums prior to release of WIPP's waste acceptance criteria (WAC). A statistical percentage of these 55 gallon drums will be opened and visually examined (VE) as part of re-characterization using Non-destructive examination (NDE) procedures. VE is an intrusive technique since the drum is opened, and as a result, there are more risks in spreading contamination. Hence, VE is performed in a glovebox to protect the workers and the environment. During VE, waste is pulled out of one drum, visually examined, the amount of plutonium measured if necessary, and the waste repackaged into one or more drums. MOVER can perform all these operations, along with having the capability to house the glovebox operations and all support equipment in a 40-foot-long container that can be transported to a site on a semi-trailer. This container is divided into three rooms, providing the level of safety and containment of a fixed facility. A key asset of mobile systems is the inherent need for modular design that reduces infrastructure costs and overhead. A mobile system like MOVER represents a technology base aimed at meeting DOE schedules to accelerate decommissioning of many sites.

  2. Structure, function, and plasticity of GABA transporters

    PubMed Central

    Scimemi, Annalisa

    2014-01-01

    GABA transporters belong to a large family of neurotransmitter:sodium symporters. They are widely expressed throughout the brain, with different levels of expression in different brain regions. GABA transporters are present in neurons and in astrocytes and their activity is crucial to regulate the extracellular concentration of GABA under basal conditions and during ongoing synaptic events. Numerous efforts have been devoted to determine the structural and functional properties of GABA transporters. There is also evidence that the expression of GABA transporters on the cell membrane and their lateral mobility can be modulated by different intracellular signaling cascades. The strength of individual synaptic contacts and the activity of entire neuronal networks may be finely tuned by altering the density, distribution and diffusion rate of GABA transporters within the cell membrane. These findings are intriguing because they suggest the existence of complex regulatory systems that control the plasticity of GABAergic transmission in the brain. Here we review the current knowledge on the structural and functional properties of GABA transporters and highlight the molecular mechanisms that alter the expression and mobility of GABA transporters at central synapses. PMID:24987330

  3. Bed Mobility on the Deschutes River, Oregon: Tracer Gravel Results

    NASA Astrophysics Data System (ADS)

    Kondolf, G. M.; Williams, J.

    2003-12-01

    The Deschutes River, drainage area 20,250 km2 near Madras, Oregon, is a gravel-bedded river, impounded since 1957 by three dams in the Pelton-Round Butte hydroelectric project, operated by Portland General Electric (PGE). Salmon spawning has declined in the reach below the dams since their construction, so possible project effects on spawning habitat are an issue of concern in relicensing of the project. Consultants to PGE applied the Parker bedload transport function to several sites below the hydroelectric dams; they concluded that the entrainment threshold flow was 340 m3s-1, and that the bed had been mobile only 25 days in the 72-year period of record from 1925-1996. However, their model was not calibrated with any actual field data of bed mobility or bedload transport, and the calculations were for full bed mobility, ignoring potentially significant bedload transport that might occur at a condition of partial mobility. To redress that lack of field data, we placed tracer gravels in the bed at three sites below the dams. In 2002 tracer gravels moved at one of the three sites after a flow of 150 m3s-1 (128-mm stones moved up to 1 m). The minor movement suggests that the bed is just beginning to move at 150 m3s-1, but indicates that the previously assumed entrainment threshold of 340 m3s-1 is too high.

  4. A Multilayer perspective for the analysis of urban transportation systems

    NASA Astrophysics Data System (ADS)

    Aleta, Alberto; Meloni, Sandro; Moreno, Yamir

    2017-03-01

    Public urban mobility systems are composed by several transportation modes connected together. Most studies in urban mobility and planning often ignore the multi-layer nature of transportation systems considering only aggregated versions of this complex scenario. In this work we present a model for the representation of the transportation system of an entire city as a multiplex network. Using two different perspectives, one in which each line is a layer and one in which lines of the same transportation mode are grouped together, we study the interconnected structure of 9 different cities in Europe raging from small towns to mega-cities like London and Berlin highlighting their vulnerabilities and possible improvements. Finally, for the city of Zaragoza in Spain, we also consider data about service schedule and waiting times, which allow us to create a simple yet realistic model for urban mobility able to reproduce real-world facts and to test for network improvements.

  5. A Multilayer perspective for the analysis of urban transportation systems

    PubMed Central

    Aleta, Alberto; Meloni, Sandro; Moreno, Yamir

    2017-01-01

    Public urban mobility systems are composed by several transportation modes connected together. Most studies in urban mobility and planning often ignore the multi-layer nature of transportation systems considering only aggregated versions of this complex scenario. In this work we present a model for the representation of the transportation system of an entire city as a multiplex network. Using two different perspectives, one in which each line is a layer and one in which lines of the same transportation mode are grouped together, we study the interconnected structure of 9 different cities in Europe raging from small towns to mega-cities like London and Berlin highlighting their vulnerabilities and possible improvements. Finally, for the city of Zaragoza in Spain, we also consider data about service schedule and waiting times, which allow us to create a simple yet realistic model for urban mobility able to reproduce real-world facts and to test for network improvements. PMID:28295015

  6. A Multilayer perspective for the analysis of urban transportation systems.

    PubMed

    Aleta, Alberto; Meloni, Sandro; Moreno, Yamir

    2017-03-15

    Public urban mobility systems are composed by several transportation modes connected together. Most studies in urban mobility and planning often ignore the multi-layer nature of transportation systems considering only aggregated versions of this complex scenario. In this work we present a model for the representation of the transportation system of an entire city as a multiplex network. Using two different perspectives, one in which each line is a layer and one in which lines of the same transportation mode are grouped together, we study the interconnected structure of 9 different cities in Europe raging from small towns to mega-cities like London and Berlin highlighting their vulnerabilities and possible improvements. Finally, for the city of Zaragoza in Spain, we also consider data about service schedule and waiting times, which allow us to create a simple yet realistic model for urban mobility able to reproduce real-world facts and to test for network improvements.

  7. Securing mobile code.

    SciTech Connect

    Link, Hamilton E.; Schroeppel, Richard Crabtree; Neumann, William Douglas; Campbell, Philip LaRoche; Beaver, Cheryl Lynn; Pierson, Lyndon George; Anderson, William Erik

    2004-10-01

    If software is designed so that the software can issue functions that will move that software from one computing platform to another, then the software is said to be 'mobile'. There are two general areas of security problems associated with mobile code. The 'secure host' problem involves protecting the host from malicious mobile code. The 'secure mobile code' problem, on the other hand, involves protecting the code from malicious hosts. This report focuses on the latter problem. We have found three distinct camps of opinions regarding how to secure mobile code. There are those who believe special distributed hardware is necessary, those who believe special distributed software is necessary, and those who believe neither is necessary. We examine all three camps, with a focus on the third. In the distributed software camp we examine some commonly proposed techniques including Java, D'Agents and Flask. For the specialized hardware camp, we propose a cryptographic technique for 'tamper-proofing' code over a large portion of the software/hardware life cycle by careful modification of current architectures. This method culminates by decrypting/authenticating each instruction within a physically protected CPU, thereby protecting against subversion by malicious code. Our main focus is on the camp that believes that neither specialized software nor hardware is necessary. We concentrate on methods of code obfuscation to render an entire program or a data segment on which a program depends incomprehensible. The hope is to prevent or at least slow down reverse engineering efforts and to prevent goal-oriented attacks on the software and execution. The field of obfuscation is still in a state of development with the central problem being the lack of a basis for evaluating the protection schemes. We give a brief introduction to some of the main ideas in the field, followed by an in depth analysis of a technique called 'white-boxing'. We put forth some new attacks and improvements

  8. 78 FR 59017 - Meeting of the Mobile Sources Technical Review Subcommittee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ... activities being conducted by EPA's Office of Transportation and Air Quality. The preliminary agenda for the... Transportation and Air Quality. BILLING CODE 6560-50-P ..., Public Law 92- 463, notice is hereby given that the Mobile Sources Technical Review Subcommittee...

  9. Dust mobilization on airless planetary bodies

    NASA Astrophysics Data System (ADS)

    Horanyi, M.

    2013-12-01

    There are a number of observations indicating that small dust grains can be mobilized and transported on the surfaces of airless bodies. While not a single measurement to date can unambiguously identify the responsible process, the entire body of existing observations as a whole suggests that electrodynamics remains the most likely candidate. If this is the case, our models have to be able to account for the electrostatic charging and subsequent dynamics of the grains sculpted by surface electric fields. The Colorado Center for Dust and Atmospheric Studies (CCLDAS) of the former NASA Lunar Science Institute conducted a series of small-scale laboratory experiments to address dust charging and mobilization issues, including the effects of flowing plasmas and UV radiation. This talk will draw conclusions based on these series of experiments and use them to guide the analysis and interpretation of the data from the Lunar Dust Experiment (LDEX) onboard the Lunar Atmosphere and Dust Environment Mission (LADEE). By the time of this talk, LADEE is expected to collect its initial science measurements. The combination of laboratory and in situ space measurements provides a unique opportunity to advance our theoretical models on the transport of charged dust particles on the lunar surface, and apply these arguments to all other airless planetary bodies.

  10. A Mobile Service Robot for Life Science Laboratories

    NASA Astrophysics Data System (ADS)

    Schulenburg, Erik; Elkmann, Norbert; Fritzsche, Markus; Teutsch, Christian

    In this paper we presents a project that is developing a mobile service robot to assist users in biological and pharmaceutical laboratories by executing routine jobs such as filling and transporting microplates. A preliminary overview of the design of the mobile platform with a robotic arm is provided. Safety aspects are one focus of the project since the robot and humans will share a common environment. Hence, several safety sensors such as laser scanners, thermographie components and artificial skin are employed. These are described along with the approaches to object recognition.

  11. ATHLETE Mobility Performance in Long-Range Traverse

    NASA Technical Reports Server (NTRS)

    Townsend, Julie

    2011-01-01

    The All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) is a modular mobility and manipulation platform being developed to support NASA operations in a variety of missions, including exploration of planetary surfaces. The agile system consists of a symmetrical arrangement of six limbs, each with seven articulated degrees of freedom and a powered wheel. This design enables transport of bulky payloads over a wide range of terrains and is envisioned as a tool to mobilize habitats, power-generation equipment, and other supplies for long-range exploration and outpost construction.

  12. Thermoelectric and bulk mobility measurements in pentacene thin films

    SciTech Connect

    Kim, Gunho; Shtein, Max; Pipe, Kevin P.

    2011-03-02

    Low-noise thermoelectric and electrical measurements were used to derive the dependences of Seebeck coefficient and hole mobility on carrier concentration and grain size in the “bulk” regions of thermally evaporated pentacene thin films (in contrast to the channel field-effect mobility typically measured using thin-film transistor geometries). Distinct charge transport regimes were observed for larger (0.5 and 0.8 μm ) and smaller (0.2 μm) grain sizes, attributed to carrier-dopant scattering and percolation, respectively.

  13. Back-gate effects and mobility characterization in junctionless transistor

    NASA Astrophysics Data System (ADS)

    Parihar, Mukta Singh; Liu, Fanyu; Navarro, Carlos; Barraud, Sylvain; Bawedin, Maryline; Ionica, Irina; Kranti, Abhinav; Cristoloveanu, Sorin

    2016-11-01

    This work addresses the effect of inter-gate coupling on back-channel characteristics of planar accumulation-mode junctionless (JL) MOSFETs, fabricated with advanced Fully Depleted Silicon-on-Insulator (FDSOI) technology. A systematic methodology to extract and distinguish the contributions of bulk and accumulation-mode mobility has been developed. Front-gate voltage strongly controls the transport properties of back channel in ultra-thin heavily doped JL devices. It is demonstrated that both volume and accumulation-layer mobility values increase when the front interface is in accumulation.

  14. Transport coefficients of He+ ions in helium

    NASA Astrophysics Data System (ADS)

    Johnsen, Rainer; Viehland, Larry; Gray, Benjamin; Wright, Timothy

    2016-09-01

    New experimental mobilities of 4He+ in 4He at 298.7 K, as a function of E/N, have been determined. Uncertainties in the mobilities were reduced to about 1% by using a shuttered drift tube. Comparison with previously measured values show that only one set of previous data is reliable. We demonstrate that the mobilities and diffusion coeffcients of 4He+ in 4He can be calculated over wide ranges of E/N with high precision if accurate potential energy curves are available for the X2Σu+ and A2Σg+ states, and if one takes into account resonant charge transfer and corrects for quantum-mechanical effects. Potentials, obtained by extrapolation of results from d-aug-cc-pVXZ (X =6,7) basis sets using the CASSCF +MRCISD approach were found to be in exceptionally close agreement with the best potentials available (separately) and with experiment, and those were subsequently used in a new computer program to determine semi-classical phase shifts and transport cross sections, from which the gaseous ion transport coefficients are determined. A new set of data for the mobilities of alpha particles (He2+) ions was obtained as a byproduct of the experiment, but the transport theory has not yet been completed.

  15. Ion mobility-mass spectrometry.

    PubMed

    Kanu, Abu B; Dwivedi, Prabha; Tam, Maggie; Matz, Laura; Hill, Herbert H

    2008-01-01

    This review article compares and contrasts various types of ion mobility-mass spectrometers available today and describes their advantages for application to a wide range of analytes. Ion mobility spectrometry (IMS), when coupled with mass spectrometry, offers value-added data not possible from mass spectra alone. Separation of isomers, isobars, and conformers; reduction of chemical noise; and measurement of ion size are possible with the addition of ion mobility cells to mass spectrometers. In addition, structurally similar ions and ions of the same charge state can be separated into families of ions which appear along a unique mass-mobility correlation line. This review describes the four methods of ion mobility separation currently used with mass spectrometry. They are (1) drift-time ion mobility spectrometry (DTIMS), (2) aspiration ion mobility spectrometry (AIMS), (3) differential-mobility spectrometry (DMS) which is also called field-asymmetric waveform ion mobility spectrometry (FAIMS) and (4) traveling-wave ion mobility spectrometry (TWIMS). DTIMS provides the highest IMS resolving power and is the only IMS method which can directly measure collision cross-sections. AIMS is a low resolution mobility separation method but can monitor ions in a continuous manner. DMS and FAIMS offer continuous-ion monitoring capability as well as orthogonal ion mobility separation in which high-separation selectivity can be achieved. TWIMS is a novel method of IMS with a low resolving power but has good sensitivity and is well intergrated into a commercial mass spectrometer. One hundred and sixty references on ion mobility-mass spectrometry (IMMS) are provided.

  16. Copper transport.

    PubMed

    Linder, M C; Wooten, L; Cerveza, P; Cotton, S; Shulze, R; Lomeli, N

    1998-05-01

    In adult humans, the net absorption of dietary copper is approximately 1 mg/d. Dietary copper joins some 4-5 mg of endogenous copper flowing into the gastrointestinal tract through various digestive juices. Most of this copper returns to the circulation and to the tissues (including liver) that formed them. Much lower amounts of copper flow into and out of other major parts of the body (including heart, skeletal muscle, and brain). Newly absorbed copper is transported to body tissues in two phases, borne primarily by plasma protein carriers (albumin, transcuprein, and ceruloplasmin). In the first phase, copper goes from the intestine to the liver and kidney; in the second phase, copper usually goes from the liver (and perhaps also the kidney) to other organs. Ceruloplasmin plays a role in this second phase. Alternatively, liver copper can also exit via the bile, and in a form that is less easily reabsorbed. Copper is also present in and transported by other body fluids, including those bathing the brain and central nervous system and surrounding the fetus in the amniotic sac. Ceruloplasmin is present in these fluids and may also be involved in copper transport there. The concentrations of copper and ceruloplasmin in milk vary with lactational stage. Parallel changes occur in ceruloplasmin messenger RNA expression in the mammary gland (as determined in pigs). Copper in milk ceruloplasmin appears to be particularly available for absorption, at least in rats.

  17. Trace metal mobilization in soil by bacterial polymers

    SciTech Connect

    Chen, Jyh-Herng; Czajka, D.R.; Lion, L.W.

    1995-02-01

    Enhanced transport of trace metal in porous media can occur in the presence of a ligand or {open_quotes}carrier{close_quotes} that has a high affinity for binding the pollutant, is dispersed and mobile in the soil environment, is recalcitrant with respect to microbial degradation, and is acceptable to the public. These aspects of the facilitated transport to trace metals are discussed with respect to a naturally occurring carrier; extracellular polymers of bacterial origin. The literature is reviewed regarding the production and composition of bacterial extracellular polymers, the processes relevant to the facilitated transport of trace metals in soil by bacterial polymers, and potential for transformation of polymers in soils by microbial degradation. Model calculations of contaminant retardation are presented for the case of polymer-mediated transport of cadmium in a sandy aquifer material. The available information suggests that extracellular polymers can bind metal ions and are mobile in the soil environment. Extracellular polymers also appear to be relatively slowly degraded by soil microorganisms. These properties and the supporting model calculations indicate that extracellular polymers of bacterial origin merit consideration as agents that may be applied to contaminated soils to enhance trace metal mobility. 58 refs., 3 figs.

  18. Comparative phloem Mobility of nickel in nonsenescent plants. [Pisum sativa L. ; Pelargonium zonale L

    SciTech Connect

    Neumann, P.M.; Chamel, A.

    1986-06-01

    /sup 63/Ni was applied to nonsenescent source leaves and found to be transported to sink tissues in pea (Pisum saativum L.) and geranium plants (Pelargonium zonale L.). The comparative mobilities (percent tracer transported out of source leaf division % /sup 86/Rb transported) for /sup 63/Ni in peas was 2.12 and in geranium 0.25. The value for the phloem mobile /sup 86/Rb was 1.00. By contrast, the comparative mobility of /sup 45/Ca, which is relatively immobile in the phloem, was low (0.05 in peas, 0.00 in geranium). Interruption of the phloem pathway between source and sink leaves by steam girdling almost completely inhibited /sup 63/Ni accumulation in the sink leaves of both species. The authors conclude that Ni is transported from nonsenescent source leaves to sink tissues via the phloem of leguminous and nonleguminous plants.

  19. Evaluation of electron mobility in InSb quantum wells by means of percentage-impact

    SciTech Connect

    Mishima, T. D.; Edirisooriya, M.; Santos, M. B.

    2014-05-15

    In order to quantitatively analyze the contribution of each scattering factor toward the total carrier mobility, we use a new convenient figure-of-merit, named a percentage impact. The mobility limit due to a scattering factor, which is widely used to summarize a scattering analysis, has its own advantage. However, a mobility limit is not quite appropriate for the above purpose. A comprehensive understanding of the difference in contribution among many scattering factors toward the total carrier mobility can be obtained by evaluating percentage impacts of scattering factors, which can be straightforwardly calculated from their mobility limits and the total mobility. Our percentage impact analysis shows that threading dislocation is one of the dominant scattering factors for the electron transport in InSb quantum wells at room temperature.

  20. Assessing Landslide Mobility Using GIS: Application to Kosrae, Micronesia

    NASA Astrophysics Data System (ADS)

    Reid, M. E.; Brien, D. L.; Godt, J.; Schmitt, R. G.; Harp, E. L.

    2015-12-01

    Deadly landslides are often mobile landslides, as exemplified by the disastrous landslide that occurred near Oso, Washington in 2014 killing 43. Despite this association, many landslide susceptibility maps do not identify runout areas. We developed a simple, GIS-based method for identifying areas potentially overrun by mobile slides and debris flows. Our method links three processes within a DEM landscape: landslide initiation, transport, and debris-flow inundation (from very mobile slides). Given spatially distributed shear strengths, we first identify initiation areas using an infinite-slope stability analysis. We then delineate transport zones, or regions of potential entrainment and/or deposition, using a height/length runout envelope. Finally, where these transport zones intersect the channel network, we start debris-flow inundation zones. The extent of inundation is computed using the USGS model Laharz, modified to include many debris-flow locations throughout a DEM. Potential debris-flow volumes are computed from upslope initiation areas and typical slide thicknesses. We applied this approach to the main island of Kosrae State, Federated States of Micronesia (FSM). In 2002, typhoon Chata'an triggered numerous landslides on the neighboring islands of Chuuk State, FSM, resulting in 43 fatalities. Using an infinite-slope stability model calibrated to the Chuuk event, we identified potential landslide initiation areas on Kosrae. We then delineated potential transport zones using a 20º runout envelope, based on runout observations from Chuuk. Potential debris-flow inundation zones were then determined using Laharz. Field inspections on Kosrae revealed that our resulting susceptibility map correctly classified areas covered by previous debris-flow deposits and did not include areas covered by fluvial deposits. Our map has the advantage of providing a visual tool to portray initiation, transport, and runout zones from mobile landslides.

  1. Adaptive mobility management scheme in hierarchical mobile IPv6

    NASA Astrophysics Data System (ADS)

    Fang, Bo; Song, Junde

    2004-04-01

    Hierarchical mobile IPv6 makes the mobility management localized. Registration with HA is only needed while MN moving between MAP domains. This paper proposed an adaptive mobility management scheme based on the hierarchical mobile IPv6. The scheme focuses on the MN operation as well as MAP operation during the handoff. Adaptive MAP selection algorithm can be used to select a suitable MAP to register with once MN moves into a new subnet while MAP can thus adaptively changing his management domain. Furthermore, MAP can also adaptively changes its level in the hierarchical referring on the service load or other related information. Detailed handoff algorithm is also discussed in this paper.

  2. From mobile mental health to mobile wellbeing: opportunities and challenges.

    PubMed

    Gaggioli, Andrea; Riva, Giuseppe

    2013-01-01

    The combination of smart phones, wearable sensor devices and social media offer new ways of monitoring and promoting mental and physical wellbeing. In this contribution, we describe recent developments in the field of mobile healthcare (or mHealth), by focusing in particular on mobile mental health applications. First, we examine the potential benefits associated with this approach, providing examples from existing projects. Next, we identify and explain possible differences in focus between mobile mental health and mobile wellbeing applications. Finally, we discuss some open challenges associated with the implementation of this vision, ranging from the lack of evidence-based validation to privacy, security and ethical concerns.

  3. Mobilizing Black America

    DTIC Science & Technology

    1992-04-01

    Hospital Charlotte, NC 1881 1966 Shaw Memorial Hospital Oxford, NC 1953 1967 Hunter Clinic Hospital Marlin, TX 1923 1967 St. Martin Pornes Hospital Mobile...D.C.: October 27, 1991), p. 12. 25 Ibid, p. 12. 18 "I didn’t have a babysitter for my other kids ." (5) "I didn’t have time." and (6) One addict...economy, including drug trafficking. He says: "Crack has created a new Horatio Alger myth for inner-city kids searching for meaning and upward

  4. Spacesuit mobility knee joints

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C. (Inventor)

    1979-01-01

    Pressure suit mobility joints are for use in interconnecting adjacent segments of an hermetically sealed spacesuit in which low torques, low leakage and a high degree of reliability are required. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics and includes linkages which restrain the joint from longitudinal distension and includes a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

  5. The Terregator Mobile Robot

    DTIC Science & Technology

    1991-05-01

    Configuration 17 4.3 Locomotor 19 4.3.1 Base Frame 20 4.3.2 Motors and Drive Train 21 4.3.3 Roll Frame 25 4.3.4 Rack Mount Enclosure 26 4.4 On-Board...Constraints The Terregator, designed to support various sensors, supplies a mounting surface on the maneuverable base vehicle. The real-time computer...mobile base to deploy and develop these navigation modes. The vehicle, therefore, had to supply a mounting surface on a maneuverable base vehicle; but

  6. Mobility and HIV.

    PubMed

    1999-01-01

    Migrants, refugees, and internally displaced people are vulnerable to HIV because they live in poor areas with little privacy, have different sexual relationships, and lack information about sexual health and services. In response to these problems, HIV prevention and care programs were initiated. The programs include: 1) involving migrant workers as both interviewers and outreach workers to better understand the idea of the migrants per Coordination of Action Research on Mobility and AIDS; 2) improving living conditions; 3) access of migrants to information and services; 4) improving the rights of the people; 5) increasing income; and 6) access to sexual health information that concerns exposure of HIV through different sexual partners.

  7. Mobile Bay turbidity study

    NASA Technical Reports Server (NTRS)

    Crozier, G. F.; Schroeder, W. W.

    1978-01-01

    The termination of studies carried on for almost three years in the Mobile Bay area and adjacent continental shelf are reported. The initial results concentrating on the shelf and lower bay were presented in the interim report. The continued scope of work was designed to attempt a refinement of the mathematical model, assess the effectiveness of optical measurement of suspended particulate material and disseminate the acquired information. The optical characteristics of particulate solutions are affected by density gradients within the medium, density of the suspended particles, particle size, particle shape, particle quality, albedo, and the angle of refracted light. Several of these are discussed in detail.

  8. Mobile Language Study

    DTIC Science & Technology

    2003-08-18

    Report 3. DATES COVERED (From – To) 15 August 2001 - 15-Aug-03 5a. CONTRACT NUMBER F61775-01-C0006 5b. GRANT NUMBER 4 . TITLE AND SUBTITLE Mobile...The proposed effort spans two years and is divided into four tasks. Tasks 1 and 2 will be completed in the first year and Tasks 3 and 4 are to be...of the first year’s research and availability of funding, the second years tasks include: Task 3: Security architecture Task 4 : Java Card and JCVM

  9. Mobilization Responses to Warning.

    DTIC Science & Technology

    1983-04-01

    reluctance by those leaders to authorized some form of response (political, economic or military) to counter early warning indicators. Strategic...MOBILIZATION RESPONSES TO WARNING Jil This document has been aIpproved L.A INDUSTRIAL COLLEGE OF THE ARMED FORCES 83 12 29 034 4 N;. -nou-n_. -Aa- f",1...48 BILIZATION RESPONSES TO WARNING MSP #46 AY 82/83 A ERFORMING :)S REPR’~ ’.,MSEP - 8.ZNRZ ~R~AN% MBEQ,’ GREGORY W. MASON, LTC, USA S ~ SI% R NAN1ZA

  10. Mobile vehicle road and weather observation quality check methods

    NASA Astrophysics Data System (ADS)

    Koller, Daniel Raymond

    Today State Departments of Transportation rely more and more on road weather data to make maintenance decisions. Inaccurate data can result in wrong treatment applications or inadequate staffing levels to maintain the roadway at the desired level of service. Previous methods of road condition data reporting have been limited to static in situ sensor stations. These road weather information systems (RWIS) provide varied data about precipitation, winds, temperature, and more, but their siting does not always provide an accurate representation of weather and road conditions along the roadway. The use of mobile data collection from vehicles travelling the highway corridors may assist in the locations where RWIS sitings are sparse or non-existent. The United States Department of Transporation's "Connected Vehicle" (formally IntelliDrive) research project is designed to create a fully connected transportation system providing road and weather data collection from an extensive array of vehicles. While the implementation of Connected Vehicle is in the future, some of the theories and technologies are already in place today. Several states, as a part of the Pooled Fund Study Maintenance Decision Support System (MDSS), have equipped their winter maintenance vehicles with Mobile Data Collection Automated / Vehicle Location (MDC/AVL) systems. In addition, since 1996, automobiles sold in the United States are required to be equipped with an Onboard Diagnostic Version 2 (OBDII) port that streams live data from sensors located in and around the vehicle. While these sensors were designed for vehicle diagnostics, some of the data can be used to determine weather characteristics around the vehicle. The OBDII data can be collected by a smartphone and sent to a server in real time to be processed. These mobile systems may fill the information gap along the roads that stationary environmental sensor stations are not able to collect. Particular concern and care needs to be focused on

  11. Perpendicular transport in superlattice bipolar transistors (SBT)

    NASA Astrophysics Data System (ADS)

    Sibille, A.; Palmier, J. F.; Minot, C.; Harmand, J. C.; Dubon-Chevallier, C.

    Diffusion-limited electron transport in superlattices is studied by gain measurements on heterojunction bipolar transistors with a {GaAs}/{GaAlAs} superlattice base. In the case of thin barriers, Bloch conduction is observed, while hopping between localized levels prevails for large barriers. A transition occurs between these two regimes, localization being achieved when the energy broadening induced by the electron-phonon coupling added to the disorder due to imperfect growth is of the order of the miniband width. This interpretation is supported by temperature dependence measurements of the perpendicular mobilities in relation with theoretical calculations of these mobilities.

  12. Trends in Mobile Application Development

    NASA Astrophysics Data System (ADS)

    Holzer, Adrian; Ondrus, Jan

    Major software companies, such as Apple and Google, are disturbing the relatively safe and established actors of the mobile application business. These newcomers have caused significant structural changes by imposing and enforcing their own rules for the future of mobile application development. The implications of these changes do not only concern the mobile network operators and mobile phone manufacturers. This changed environment also brings additional opportunities and constraints for current mobile application developers. Therefore, developers need to assess what their options are and how they can take advantages of these current trends. In this paper, we take a developer’s perspective in order to explore how the structural changes will influence the mobile application development markets. Moreover, we discuss what aspects developers need to take into account in order to position themselves within the current trends.

  13. Molecular transport in collagenous tissues measured by gel electrophoresis.

    PubMed

    Hunckler, Michael D; Tilley, Jennifer M R; Roeder, Ryan K

    2015-11-26

    Molecular transport in tissues is important for drug delivery, nutrient supply, waste removal, cell signaling, and detecting tissue degeneration. Therefore, the objective of this study was to investigate gel electrophoresis as a simple method to measure molecular transport in collagenous tissues. The electrophoretic mobility of charged molecules in tissue samples was measured from relative differences in the velocity of a cationic dye passing through an agarose gel in the absence and presence of a tissue section embedded within the gel. Differences in electrophoretic mobility were measured for the transport of a molecule through different tissues and tissue anisotropy, or the transport of different sized molecules through the same tissue. Tissue samples included tendon and fibrocartilage from the proximal (tensile) and distal (compressive) regions of the bovine flexor tendon, respectively, and bovine articular cartilage. The measured electrophoretic mobility was greatest in the compressive region of the tendon (fibrocartilage), followed by the tensile region of tendon, and lowest in articular cartilage, reflecting differences in the composition and organization of the tissues. The anisotropy of tendon was measured by greater electrophoretic mobility parallel compared with perpendicular to the predominate collagen fiber orientation. Electrophoretic mobility also decreased with increased molecular size, as expected. Therefore, the results of this study suggest that gel electrophoresis may be a useful method to measure differences in molecular transport within various tissues, including the effects of tissue type, tissue anisotropy, and molecular size.

  14. Creating a Mobile Library Website

    ERIC Educational Resources Information Center

    Cutshall, Tom C.; Blake, Lindsay; Bandy, Sandra L.

    2011-01-01

    The overwhelming results were iPhones and Android devices. Since the library wasn't equipped technologically to develop an in-house application platform and because we wanted the content to work across all mobile platforms, we decided to focus on creating a mobile web-based platform. From the NLM page of mobile sites we chose the basic PubMed/…

  15. Cognitive Radio will revolutionize American transportation

    ScienceCinema

    None

    2016-07-12

    Cognitive Radio will revolutionize American transportation. Through smart technology, it will anticipate user needs; detect available bandwidths and frequencies then seamlessly connect vehicles, infrastructures, and consumer devices; and it will support the Department of Transportation IntelliDrive Program, helping researchers, auto manufacturers, and Federal and State officials advance the connectivity of US transportation systems for improved safety, mobility, and environmental conditions. Using cognitive radio, a commercial vehicle will know its driver, onboard freight and destination route. Drivers will save time and resources communicating with automatic toll booths and know ahead of time whether to stop at a weigh station or keep rolling. At accident scenes, cognitive radio sensors on freight and transportation modes can alert emergency personnel and measure on-site, real-time conditions such as a chemical leak. The sensors will connect freight to industry, relaying shipment conditions and new delivery schedules. For industry or military purposes, cognitive radio will enable real-time freight tracking around the globe and its sensory technology can help prevent cargo theft or tampering by alerting shipper and receiver if freight is tampered with while en route. For the average consumer, a vehicle will tailor the transportation experience to the passenger such as delivering age-appropriate movies via satellite. Cognitive radio will enhance transportation safety by continually sensing what is important to the user adapting to its environment and incoming information, and proposing solutions that improve mobility and quality of life.

  16. Cognitive Radio will revolutionize American transportation

    SciTech Connect

    2013-07-22

    Cognitive Radio will revolutionize American transportation. Through smart technology, it will anticipate user needs; detect available bandwidths and frequencies then seamlessly connect vehicles, infrastructures, and consumer devices; and it will support the Department of Transportation IntelliDrive Program, helping researchers, auto manufacturers, and Federal and State officials advance the connectivity of US transportation systems for improved safety, mobility, and environmental conditions. Using cognitive radio, a commercial vehicle will know its driver, onboard freight and destination route. Drivers will save time and resources communicating with automatic toll booths and know ahead of time whether to stop at a weigh station or keep rolling. At accident scenes, cognitive radio sensors on freight and transportation modes can alert emergency personnel and measure on-site, real-time conditions such as a chemical leak. The sensors will connect freight to industry, relaying shipment conditions and new delivery schedules. For industry or military purposes, cognitive radio will enable real-time freight tracking around the globe and its sensory technology can help prevent cargo theft or tampering by alerting shipper and receiver if freight is tampered with while en route. For the average consumer, a vehicle will tailor the transportation experience to the passenger such as delivering age-appropriate movies via satellite. Cognitive radio will enhance transportation safety by continually sensing what is important to the user adapting to its environment and incoming information, and proposing solutions that improve mobility and quality of life.

  17. The Mobile Chamber

    NASA Technical Reports Server (NTRS)

    Scharfstein, Gregory; Cox, Russell

    2012-01-01

    A document discusses a simulation chamber that represents a shift from the thermal-vacuum chamber stereotype. This innovation, currently in development, combines the capabilities of space simulation chambers, the user-friendliness of modern-day electronics, and the modularity of plug-and-play computing. The Mobile Chamber is a customized test chamber that can be deployed with great ease, and is capable of bringing payloads at temperatures down to 20 K, in high vacuum, and with the desired metrology instruments integrated to the systems control. Flexure plans to lease Mobile Chambers, making them affordable for smaller budgets and available to a larger customer base. A key feature of this design will be an Apple iPad-like user interface that allows someone with minimal training to control the environment inside the chamber, and to simulate the required extreme environments. The feedback of thermal, pressure, and other measurements is delivered in a 3D CAD model of the chamber's payload and support hardware. This GUI will provide the user with a better understanding of the payload than any existing thermal-vacuum system.

  18. Ghana social mobilization analysis.

    PubMed

    Tweneboa-Kodua, A; Obeng-Quaidoo, I; Abu, K

    1991-01-01

    In order to increase communication channels for child survival and development, the government and UNICEF Ghana undertook a "social mobilization analysis." This analysis included three studies that aimed to identify individuals and existing organizations with the potential to serve as health communicators and to determine the type of assistance that they needed to maximize their effectiveness in this role. The first study surveyed governmental institutions, trade unions, revolutionary organizations, traditional leaders, and others and found a largely untapped reservoir of capacities to promote child health, with varying levels of current involvement. The primary need identified was for information and training materials. The second study focused on the mass media and revealed a low coverage of maternal and child health topics and the need for better cooperation between journalists and health professionals. The third study assessed sources of health information for parents and found several sources, such as religious organizations, women's groups, and school teachers that could be mobilized to promote child health. Recommendations are made for the use of the findings.

  19. Mobility in old age.

    PubMed

    Walsh, K; Roberts, J; Bennett, G

    1999-12-01

    Immobility is common in older people and may impact on their dental care. Immobility in old age may have physical, psychological and environmental causes. Immobile elderly people often suffer from a number of diseases which worsen their mobility. Arthritis, osteoporosis, hip fracture, stroke and Parkinson's disease are among the most common causes of immobility in old age. Complications of immobility such as orthostatic hypotension may occur in the dental patient. Careful history-taking and a thorough physical examination by the physician are the most important parts of the assessment process. This assessment should lead to a list of active problems and treatment should then be aimed at these problems. Active management, carried out by the multidisciplinary team, will lead to improvements in mobility and lessen the frequency and severity of the complications of immobility. This broad description thus provides the basis for a wide understanding for the special problems that the immobile patient present to the practitioner and ways of overcoming the problems.

  20. A techno-economic analysis of using mobile distributed pyrolysis facilities to deliver a forest residue resource.

    PubMed

    Brown, Duncan; Rowe, Andrew; Wild, Peter

    2013-12-01

    Distributed mobile conversion facilities using either fast pyrolysis or torrefaction processes can be used to convert forest residues to more energy dense substances (bio-oil, bio-slurry or torrefied wood) that can be transported as feedstock for bio-fuel facilities. Results show that the levelised delivered cost of a forest residue resource using mobile facility networks can be lower than using conventional woodchip delivery methods under appropriate conditions. Torrefied wood is the lowest cost pathway of delivering a forest residue resource when using mobile facilities. Cost savings occur against woodchip delivery for annual forest residue harvests above 2.5 million m(3) or when transport distances greater than 300 km are required. Important parameters that influence levelised delivered costs are transport distances (forest residue spatial density), haul cost factors, and initial moisture content of forest residues. Relocating mobile facilities can be optimised for lowest cost delivery as transport distances of raw biomass are reduced.