Sample records for accelerator center leads

  1. Illinois Accelerator Research Center

    DOE PAGES

    Kroc, Thomas K.; Cooper, Charlie A.

    2017-10-26

    The Illinois Accelerator Research Center (IARC) hosts a new accelerator development program at Fermi National Accelerator Laboratory. IARC provides access to Fermi's state-of-the-art facilities and technologies for research, development and industrialization of particle accelerator technology. In addition to facilitating access to available existing Fermi infrastructure, the IARC Campus has a dedicated 36,000 ft2 heavy assembly building (HAB) with all the infrastructure needed to develop, commission and operate new accelerators. Connected to the HAB is a 47,000 ft Office, Technology and Engineering (OTE) building, paid for by the state, that has office, meeting, and light technical space. The OTE building, whichmore » contains the Accelerator Physics Center, and nearby Accelerator and Technical divisions provide IARC collaborators with unique access to world class expertise in a wide array of accelerator technologies. Finally, at IARC scientists and engineers from Fermilab and academia work side by side with industrial partners to develop breakthroughs in accelerator science and translate them into applications for the nation's health, wealth and security.« less

  2. Illinois Accelerator Research Center

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

    Kroc, Thomas K.; Cooper, Charlie A.

    The Illinois Accelerator Research Center (IARC) hosts a new accelerator development program at Fermi National Accelerator Laboratory. IARC provides access to Fermi's state-of-the-art facilities and technologies for research, development and industrialization of particle accelerator technology. In addition to facilitating access to available existing Fermi infrastructure, the IARC Campus has a dedicated 36,000 ft2 heavy assembly building (HAB) with all the infrastructure needed to develop, commission and operate new accelerators. Connected to the HAB is a 47,000 ft Office, Technology and Engineering (OTE) building, paid for by the state, that has office, meeting, and light technical space. The OTE building, whichmore » contains the Accelerator Physics Center, and nearby Accelerator and Technical divisions provide IARC collaborators with unique access to world class expertise in a wide array of accelerator technologies. Finally, at IARC scientists and engineers from Fermilab and academia work side by side with industrial partners to develop breakthroughs in accelerator science and translate them into applications for the nation's health, wealth and security.« less

  3. Illinois Accelerator Research Center

    NASA Astrophysics Data System (ADS)

    Kroc, Thomas K.; Cooper, Charlie A.

    The Illinois Accelerator Research Center (IARC) hosts a new accelerator development program at Fermi National Accelerator Laboratory. IARC provides access to Fermi's state-of-the-art facilities and technologies for research, development and industrialization of particle accelerator technology. In addition to facilitating access to available existing Fermi infrastructure, the IARC Campus has a dedicated 36,000 ft2 Heavy Assembly Building (HAB) with all the infrastructure needed to develop, commission and operate new accelerators. Connected to the HAB is a 47,000 ft2 Office, Technology and Engineering (OTE) building, paid for by the state, that has office, meeting, and light technical space. The OTE building, which contains the Accelerator Physics Center, and nearby Accelerator and Technical divisions provide IARC collaborators with unique access to world class expertise in a wide array of accelerator technologies. At IARC scientists and engineers from Fermilab and academia work side by side with industrial partners to develop breakthroughs in accelerator science and translate them into applications for the nation's health, wealth and security.

  4. Fermilab | Illinois Accelerator Research Center | Illinois Accelerator

    Science.gov Websites

    Department of Commerce and Economic Opportunity and the U.S. Department of Energy. Construction Progress as Research Center IARC Illinois Accelerator Research Center Fermilab U.S. Department of Energy Stewardship Pilot Program Contact IARC Funded By Illinois Department of Commerce and Economic Opportunity U.S

  5. The Accelerated Schools Movement: Expansion and Support through Accelerated Schools Centers.

    ERIC Educational Resources Information Center

    Brunner, Ilse; And Others

    From 1987 to 1995, the Accelerated Schools Project moved from a two-school pilot project to a national movement of over 700 schools in 35 states. This paper examines how the Accelerated Schools Centers have helped the expansion of the accelerated schools movement by recruiting and supporting schools in their regions, and how their institutional…

  6. Fermilab | Tevatron | Accelerator

    Science.gov Websites

    Leading accelerator technology Accelerator complex Illinois Accelerator Research Center Fermilab temperature. They were used to transfer particles from one part of the Fermilab accelerator complex to another center ring of Fermilab's accelerator complex. Before the Tevatron shut down, it had three primary

  7. IARC - Illinois Accelerator Research Center | Pilot Program

    Science.gov Websites

    Toggle navigation Pilot Program Agenda Directions Registration Illinois Accelerator Research Center National Laboratory present Accelerator Stewardship Test Facility Pilot Program Use accelerator technology , energy and environment. With this pilot program, the DOE Office of Science National Laboratories are

  8. Leading the Learner-Centered Campus

    ERIC Educational Resources Information Center

    Stamm, Liesa

    2011-01-01

    For those who advocate for greater attention to the development of the whole student, promoting a climate of student-centered learning on our campuses should be a major component of our endeavors. In "Leading the Learner-Centered Campus", Harris and Cullen provide some concrete proposals for achieving student-centered learning as central to the…

  9. LIONs at the Stanford Linear Accelerator Center

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

    Constant, T.N.; Zdarko, R.W.; Simmons, R.H.

    1998-01-01

    The term LION is an acronym for Long Ionization Chamber. This is a distributed ion chamber which is used to monitor secondary ionization along the shield walls of a beam line resulting from incorrectly steered charged particle beams in lieu of the use of many discrete ion chambers. A cone of ionizing radiation emanating from a point source as a result of incorrect steering intercepts a portion of 1-5/8 inch Heliax cable (about 100 meters in length) filled with Argon gas at 20 psi and induces a pulsed current which is proportional to the ionizing charge. This signal is transmittedmore » via the cable to an integrator circuit whose output is directed to an electronic comparators, which in turn is used to turn off the accelerated primary beam when preset limits are exceeded. This device is used in the Stanford Linear Accelerator Center (SLAC) Beam Containment System (BCS) to prevent potentially hazardous ionizing radiation resulting from incorrectly steered beams in areas that might be occupied by people. This paper describes the design parameters and experience in use in the Final Focus Test Beam (FFTB) area of the Stanford Linear Accelerator Center.« less

  10. Accelerated Aging of Lead-Free Propellant

    NASA Technical Reports Server (NTRS)

    Furrow, Keith W.; Jervey, David D.

    2000-01-01

    Following higher than expected 2-NDPA depletion rates in a lead-free doublebase formulation (RPD-422), an accelerated aging study was conducted to verify the depletion rates. A test plan was prepared to compare the aging characteristics of lead-free propellant and NOSIH-AA2. The study was also designed to determine which lead-free ballistic modifiers accelerated 2-NDPA depletion. The increased depletion rate occurred in propellants containing monobasic copper salicylate. Four lead-free propellants were then formulated to improved aging characteristics over previous lead-free propellant formulations. The new formulations reduced or replaced the monobasic copper salicylate. The new formulations had improved aging characteristics. Their burn rates, however, were unacceptable for use in a 2.75 inch rocket. To compare aging characteristics, stabilizer depletion rates of RPD-422, AA2, M28, and RLC 470/6A were measured or taken from the literature. The data were fit to a kinetic model. The model contained first and zero order terms which allowed the stabilizer concentration to go to zero. In the model, only the concentration of the primary stabilizer was considered. Derivatives beyond the first nitrated or nitroso derivative of 2-NPDA were not considered. The rate constants were fit to the Arrhenius equation and extrapolated to lower temperatures. The time to complete stabilizer depletion was estimated using the kinetic model. The four propellants were compared and the RPD-422 depleted faster at 45 C than both A22 and M28. These types of predictions depend on the validity of the model and on confidence in the Arrhenius relationship holding at lower temperatures. At 45 C, the zero order portion of the model dominates the depletion rate.

  11. Marshak Lectureship: The Turkish Accelerator Center, TAC

    NASA Astrophysics Data System (ADS)

    Yavas, Omer

    2012-02-01

    The Turkish Accelerator Center (TAC) project is comprised of five different electron and proton accelerator complexes, to be built over 15 years, with a phased approach. The Turkish Government funds the project. Currently there are 23 Universities in Turkey associated with the TAC project. The current funded project, which is to run until 2013 aims *To establish a superconducting linac based infra-red free electron laser and Bremsstrahlung Facility (TARLA) at the Golbasi Campus of Ankara University, *To establish the Institute of Accelerator Technologies in Ankara University, and *To complete the Technical Design Report of TAC. The proposed facilities are a 3^rd generation Synchrotron Radiation facility, SASE-FEL facility, a GeV scale Proton Accelerator facility and an electron-positron collider as a super charm factory. In this talk, an overview on the general status and road map of TAC project will be given. National and regional importance of TAC will be expressed and the structure of national and internatonal collaborations will be explained.

  12. The Galactic Center: A Petaelectronvolt Cosmic-ray Acceleration Factory

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

    Guo, Yi-Qing; Tian, Zhen; Wang, Zhen

    2017-02-20

    The multiteraelectronvolt γ -rays from the galactic center (GC) have a cutoff at tens of teraelectronvolts, whereas the diffuse emission has no such cutoff, which is regarded as an indication of petaelectronvolt proton acceleration by the HESS experiment. It is important to understand the inconsistency and study the possibility that petaelectronvolt cosmic-ray acceleration could account for the apparently contradictory point and diffuse γ -ray spectra. In this work, we propose that the cosmic rays are accelerated up to greater than petaelectronvolts in the GC. The interaction between cosmic rays and molecular clouds is responsible for the multiteraelectronvolt γ -ray emissionsmore » from both the point and diffuse sources today. Enhanced by the small volume filling factor (VFF) of the clumpy structure, the absorption of the γ -rays leads to a sharp cutoff spectrum at tens of teraelectronvolts produced in the GC. Away from the GC, the VFF grows, and the absorption enhancement becomes negligible. As a result, the spectra of γ -ray emissions for both point and diffuse sources can be successfully reproduced under such a self-consistent picture. In addition, a “surviving tail” at ∼100 TeV is expected from the point source, which can be observed by future projects CTA and LHAASO. Neutrinos are simultaneously produced during proton-proton (PP) collision. With 5–10 years of observations, the KM3Net experiment will be able to detect the petaelectronvolt source according to our calculation.« less

  13. Analysis of lead-acid battery accelerated testing data

    NASA Astrophysics Data System (ADS)

    Clifford, J. E.; Thomas, R. E.

    1983-06-01

    Battelle conducted an independent review and analysis of the accelerated test procedures and test data obtained by Exide in the 3 year Phase 1 program to develop advanced lead acid batteries for utility load leveling. Of special importance is the extensive data obtained in deep discharge cycling tests on 60 cells at elevated temperatures over a 2-1/2 year period. The principal uncertainty in estimating cell life relates to projecting cycle life data at elevated temperature to the lower operating temperatures. The accelerated positive grid corrosion test involving continuous overcharge at 500C provided some indication of the degree of grid corrosion that might be tolerable before failure. The accelerated positive material shedding test was not examined in any detail. Recommendations are made for additional studies.

  14. Organoid Center Strategies for Accelerating Clinical Translation.

    PubMed

    Takebe, Takanori; Wells, James M; Helmrath, Michael A; Zorn, Aaron M

    2018-06-01

    The meteoric rise in stem-cell-derived organoid technologies has ushered in a new era of "organoid medicine." Here we discuss how an organoid center can accelerate the translation of laboratory proof-of-principle experiments into clinical practice by developing and utilizing shared platforms for commercial and medical applications. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. The status and road map of Turkish Accelerator Center (TAC)

    NASA Astrophysics Data System (ADS)

    Yavaş, Ö.

    2012-02-01

    Turkish Accelerator Center (TAC) project is supported by the State Planning Organization (SPO) of Turkey and coordinated by Ankara University. After having completed the Feasibility Report (FR) in 2000 and the Conceptual Design Report (CDR) in 2005, third phase of the project started in 2006 as an inter-universities project including ten Turkish Universities with the support of SPO. Third phase of the project has two main scientific goals: to prepare the Technical Design Report (TDR) of TAC and to establish an Infrared Free Electron Laser (IR FEL) facility, named as Turkish Accelerator and Radiation Laboratory at Ankara (TARLA) as a first step. The facility is planned to be completed in 2015 and will be based on 15-40 MeV superconducting linac. In this paper, main aims, national and regional importance, main parts main parameters, status and road map of Turkish Accelerator Center will be presented.

  16. Accelerated Schools Centers: How To Address Challenges to Institutionalization and Growth.

    ERIC Educational Resources Information Center

    Meza, James, Jr.

    The Accelerated Schools Project (ASP) at the University of New Orleans (UNO) was established in spring 1990, funded by a 3-year grant from Chevron. Beginning with 1 pilot school in 1991, the UNO Accelerated Schools Center has expanded to 36 schools representing 19 school districts in Louisiana and 3 schools from the Memphis City Schools district.…

  17. Testing for lead in toys at day care centers.

    PubMed

    Sanders, Martha; Stolz, Julie; Chacon-Baker, Ashley

    2013-01-01

    Exposure to lead-based paint or material has been found to impact children's cognitive and behavioral development at blood lead levels far below current standards. The purpose of the project was to screen for lead in toy items in daycare centers in order to raise awareness of inside environmental lead exposures and minimize lead-based exposures for children. Occupational therapy students in a service learning class tested for lead in ten daycare or public centers using the XRF Thermo Scientific Niton XL3t, a method accepted by the Consumer Product Safety Commission (CPSC). A total of 460 items were tested over a two-month period for an average of 66 toys per setting. Fifty six (56) items tested > 100 ppm, which represented 12% of the entire sample. Items with high lead levels included selected toys constructed with lead-based paint, lead metals, plastics using lead as a color enhancer, and decorative objects. While the actual number of lead-based products is small, the cumulative exposure or habitual use may pose an unnecessary risk to children. Indoor exposures occurred for all day care centers regardless of socio-economic levels. Recommendations to minimize exposures are provided.

  18. Alternative Fuels Data Center: San Diego Leads in Promoting EVs

    Science.gov Websites

    of a school bus Michigan Transports Students in Hybrid Electric School Buses Jan. 4, 2014 Photo of San Diego Leads in Promoting EVs to someone by E-mail Share Alternative Fuels Data Center: San Diego Leads in Promoting EVs on Facebook Tweet about Alternative Fuels Data Center: San Diego Leads in

  19. Developments and applications of accelerator system at the Wakasa Wan Energy Research Center

    NASA Astrophysics Data System (ADS)

    Hatori, S.; Kurita, T.; Hayashi, Y.; Yamada, M.; Yamada, H.; Mori, J.; Hamachi, H.; Kimura, S.; Shimoda, T.; Hiroto, M.; Hashimoto, T.; Shimada, M.; Yamamoto, H.; Ohtani, N.; Yasuda, K.; Ishigami, R.; Sasase, M.; Ito, Y.; Hatashita, M.; Takagi, K.; Kume, K.; Fukuda, S.; Yokohama, N.; Kagiya, G.; Fukumoto, S.; Kondo, M.

    2005-12-01

    At the Wakasa Wan Energy Research Center (WERC), an accelerator system with a 5 MV tandem accelerator and a 200 MeV proton synchrotron is used for ion beam analyses and irradiation experiments. The study of cancer therapy with a proton beam is also performed. Therefore, the stable operation and efficient sharing of beam time of the system are required, based on the treatment standard. Recent developments and the operation status of the system put stress on the tandem accelerator operation, magnifying the problems.

  20. Radiation Pressure Forces, the Anomalous Acceleration, and Center of Mass Motion for the TOPEX/POSEIDON Spacecraft

    NASA Technical Reports Server (NTRS)

    Kubitschek, Daniel G.; Born, George H.

    2000-01-01

    Shortly after launch of the TOPEX/POSEIDON (T/P) spacecraft (s/c), the Precision Orbit Determination (POD) Team at NASA's Goddard Space Flight Center (GSFC) and the Center for Space Research at the University of Texas, discovered residual along-track accelerations, which were unexpected. Here, we describe the analysis of radiation pressure forces acting on the T/P s/c for the purpose of understanding and providing an explanation for the anomalous accelerations. The radiation forces acting on the T/P solar army, which experiences warping due to temperature gradients between the front and back surfaces, are analyzed and the resulting along-track accelerations are determined. Characteristics similar to those of the anomalous acceleration are seen. This analysis led to the development of a new radiation form model, which includes solar array warping and a solar array deployment deflection of as large as 2 deg. As a result of this new model estimates of the empirical along-track acceleration are reduced in magnitude when compared to the GSFC tuned macromodel and are less dependent upon beta(prime), the location of the Sun relative to the orbit plane. If these results we believed to reflect the actual orientation of the T/P solar array then motion of the solar array must influence the location of the s/c center of mass. Preliminary estimates indicate that the center of mass can vary by as much as 3 cm in the radial component of the s/c's position due to rotation of the deflected, warped solar array panel .The altimeter measurements rely upon accurate knowledge of the center of mass location relative to the s/c frame of reference. Any radial motion of the center of mass directly affects the altimeter measurements.

  1. Rotational accelerations stabilize leading edge vortices on revolving fly wings.

    PubMed

    Lentink, David; Dickinson, Michael H

    2009-08-01

    The aerodynamic performance of hovering insects is largely explained by the presence of a stably attached leading edge vortex (LEV) on top of their wings. Although LEVs have been visualized on real, physically modeled, and simulated insects, the physical mechanisms responsible for their stability are poorly understood. To gain fundamental insight into LEV stability on flapping fly wings we expressed the Navier-Stokes equations in a rotating frame of reference attached to the wing's surface. Using these equations we show that LEV dynamics on flapping wings are governed by three terms: angular, centripetal and Coriolis acceleration. Our analysis for hovering conditions shows that angular acceleration is proportional to the inverse of dimensionless stroke amplitude, whereas Coriolis and centripetal acceleration are proportional to the inverse of the Rossby number. Using a dynamically scaled robot model of a flapping fruit fly wing to systematically vary these dimensionless numbers, we determined which of the three accelerations mediate LEV stability. Our force measurements and flow visualizations indicate that the LEV is stabilized by the ;quasi-steady' centripetal and Coriolis accelerations that are present at low Rossby number and result from the propeller-like sweep of the wing. In contrast, the unsteady angular acceleration that results from the back and forth motion of a flapping wing does not appear to play a role in the stable attachment of the LEV. Angular acceleration is, however, critical for LEV integrity as we found it can mediate LEV spiral bursting, a high Reynolds number effect. Our analysis and experiments further suggest that the mechanism responsible for LEV stability is not dependent on Reynolds number, at least over the range most relevant for insect flight (100

  2. 13 CFR 130.320 - Location of lead centers and SBDC service providers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Location of lead centers and SBDC service providers. 130.320 Section 130.320 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS DEVELOPMENT CENTERS § 130.320 Location of lead centers and SBDC service providers. (a...

  3. 13 CFR 130.320 - Location of lead centers and SBDC service providers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Location of lead centers and SBDC service providers. 130.320 Section 130.320 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS DEVELOPMENT CENTERS § 130.320 Location of lead centers and SBDC service providers. (a...

  4. Modeling of Blood Lead Levels in Astronauts Exposed to Lead from Microgravity-Accelerated Bone Loss

    NASA Technical Reports Server (NTRS)

    Garcia, H.; James, J.; Tsuji, J.

    2014-01-01

    Human exposure to lead has been associated with toxicity to multiple organ systems. Studies of various population groups with relatively low blood lead concentrations (<10 µg/dL) have indicated associations of blood lead level with lower cognitive test scores in children, later onset of puberty in girls, and increased blood pressure and cardiovascular mortality rates in adults. Cognitive effects are considered by regulatory agencies to be the most sensitive endpoint at low doses. Although 95% of the body burden of lead is stored in the bones, the adverse effects of lead correlate with the concentration of lead in the blood better than with that in the bones. NASA has found that prolonged exposure to microgravity during spaceflight results in a significant loss of bone minerals, the extent of which varies from individual to individual and from bone to bone, but generally averages about 0.5% per month. During such bone loss, lead that had been stored in bones would be released along with calcium. The effects on the concentration of lead in the blood (PbB) of various concentrations of lead in drinking water (PbW) and of lead released from bones due to accelerated osteoporosis in microgravity, as well as changes in exposure to environmental lead before, during, and after spaceflight were evaluated using a physiologically based pharmacokinetic (PBPK) model that incorporated exposure to environmental lead both on earth and in flight and included temporarily increased rates of osteoporosis during spaceflight.

  5. Solar wind conditions leading to efficient radiation belt electron acceleration: A superposed epoch analysis

    DOE PAGES

    Li, W.; Thorne, R. M.; Bortnik, J.; ...

    2015-09-07

    In this study by determining preferential solar wind conditions leading to efficient radiation belt electron acceleration is crucial for predicting radiation belt electron dynamics. Using Van Allen Probes electron observations (>1 MeV) from 2012 to 2015, we identify a number of efficient and inefficient acceleration events separately to perform a superposed epoch analysis of the corresponding solar wind parameters and geomagnetic indices. By directly comparing efficient and inefficient acceleration events, we clearly show that prolonged southward Bz, high solar wind speed, and low dynamic pressure are critical for electron acceleration to >1 MeV energies in the heart of the outermore » radiation belt. We also evaluate chorus wave evolution using the superposed epoch analysis for the identified efficient and inefficient acceleration events and find that chorus wave intensity is much stronger and lasts longer during efficient electron acceleration events, supporting the scenario that chorus waves play a key role in MeV electron acceleration.« less

  6. Naked singularities as particle accelerators

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

    Patil, Mandar; Joshi, Pankaj S.

    We investigate here the particle acceleration by naked singularities to arbitrarily high center of mass energies. Recently it has been suggested that black holes could be used as particle accelerators to probe the Planck scale physics. We show that the naked singularities serve the same purpose and probably would do better than their black hole counterparts. We focus on the scenario of a self-similar gravitational collapse starting from a regular initial data, leading to the formation of a globally naked singularity. It is seen that when particles moving along timelike geodesics interact and collide near the Cauchy horizon, the energymore » of collision in the center of mass frame will be arbitrarily high, thus offering a window to Planck scale physics.« less

  7. UNC Cancer Center Director to Lead NCI.

    PubMed

    2017-08-01

    President Donald Trump has selected Norman "Ned" Sharpless, MD, director of the University of North Carolina Lineberger Comprehensive Cancer Center, to lead the NCI. The news was met with widespread approval among cancer researchers, who view Sharpless as a strong communicator who can ably represent the needs of the cancer community in the face of proposed funding cuts. ©2017 American Association for Cancer Research.

  8. Rail accelerator research at Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Kerslake, W. R.; Cybyk, B. Z.

    1982-01-01

    A rail accelerator was chosen for study as an electromagnetic space propulsion device because of its simplicity and existing technology base. The results of a mission feasibility study using a large rail accelerator for direct launch of ton-size payloads from the Earth's surface to space, and the results of initial tests with a small, laboratory rail accelerator are presented. The laboratory rail accelerator has a bore of 3 by 3 mm and has accelerated 60 mg projectiles to velocities of 300 to 1000 m/s. Rail materials of Cu, W, and Mo were tested for efficiency and erosion rate.

  9. Center of pressure velocity reflects body acceleration rather than body velocity during quiet standing.

    PubMed

    Masani, Kei; Vette, Albert H; Abe, Masaki O; Nakazawa, Kimitaka

    2014-03-01

    The purpose of this study was to test the hypothesis that the center of pressure (COP) velocity reflects the center of mass (COM) acceleration due to a large derivative gain in the neural control system during quiet standing. Twenty-seven young (27.2±4.5 years) and twenty-three elderly (66.2±5.0 years) subjects participated in this study. Each subject was requested to stand quietly on a force plate for five trials, each 90 s long. The COP and COM displacements, the COP and COM velocities, and the COM acceleration were acquired via a force plate and a laser displacement sensor. The amount of fluctuation of each variable was quantified using the root mean square. Following the experimental study, a simulation study was executed to investigate the experimental findings. The experimental results revealed that the COP velocity was correlated with the COM velocity, but more highly correlated with the COM acceleration. The equation of motion of the inverted pendulum model, however, accounts only for the correlation between the COP and COM velocities. These experimental results can be meaningfully explained by the simulation study, which indicated that the neural motor command presumably contains a significant portion that is proportional to body velocity. In conclusion, the COP velocity fluctuation reflects the COM acceleration fluctuation rather than the COM velocity fluctuation, implying that the neural motor command controlling quiet standing posture contains a significant portion that is proportional to body velocity. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Lead, Allergen, and Pesticide Levels in Licensed Child Care Centers in the United States

    EPA Science Inventory

    The First National Environmental Health Survey of Child Care Centers was conducted to provide information about lead, allergens, and pesticide levels in licensed U.S. child care centers. Lead levels were measured in settled dust, paint, and play area soil; indoor allergen levels ...

  11. Translational Partnership Development Lead | Center for Cancer Research

    Cancer.gov

    PROGRAM DESCRIPTION The Frederick National Laboratory for Cancer Research (FNLCR) is a Federally Funded Research and Development Center operated by Leidos Biomedical Research, Inc on behalf of the National Cancer Institute (NCI). The staff of FNLCR support the NCI’s mission in the fight against cancer and HIV/AIDS. Currently we are seeking a Translational Partnership Development Lead (TPDL) who will work closely with the Office of Translational Resources (OTR) within the Office of the Director (OD) of NCI’s Center for Cancer Research (CCR) to facilitate the successful translation of CCR’s basic and preclinical research advances into new therapeutics and diagnostics. The TPDL with be strategically aligned within FNLCR’s Partnership Development Office (PDO), to maximally leverage the critical mass of expertise available within the PDO. CCR comprises the basic and clinical components of the NCI’s Intramural Research Program (IRP) and consists of ~230 basic and clinical Investigators located at either the NIH main campus in Bethesda or the NCI-Frederick campus. CCR Investigators are focused primarily on cancer and HIV/AIDS, with special emphasis on the most challenging and important high-risk/high-reward problems driving the fields. (See https://ccr.cancer.gov for a full delineation of CCR Investigators and their research activities.) The process of developing research findings into new clinical applications is high risk, complex, variable, and requires multiple areas of expertise seldom available within the confines of a single Investigator’s laboratory. To accelerate this process, OTR serves as a unifying force within CCR for all aspects of translational activities required to achieve success and maintain timely progress. A key aspect of OTR’s function is to develop and strengthen essential communications and collaborations within NIH, with extramural partners and with industry to bring together experts in chemistry, human subjects research

  12. Lead Paint Exposure Assessment in High Bays of Johnson Space Center

    NASA Technical Reports Server (NTRS)

    Stanch, Penney; Plaza, Angel; Keprta, Sean

    2008-01-01

    This slide presentation reviews the program to assess the possibility of lead paint exposure in the high bays of some of the Johnson Space Center buildings. Some of the buildings in the Manned Space Flight Center (MSC) were built in 1962 and predate any considerations to reduce lead in paints and coatings. There are many of these older buildings that contain open shops and work areas that have open ceilings, These shops include those that had operations that use leaded gasoline, batteries, and lead based paints. Test were planned to be conducted in three phases: (1) Surface Dust sampling, (2) personal exposure montioring, and (3) Ceiling paint Sampling. The results of the first two phases were reviewed. After considering the results of the first two phases, and the problems associated with the retrieval of samples from high ceilings, it was determined that the evaluation of ceiling coatings would be done on a project by project and in response to a complaint.

  13. Pulse Generator Exchange Does Not Accelerate the Rate of Electrical Failure in a Recalled Small Caliber ICD Lead.

    PubMed

    Lovelock, Joshua D; Premkumar, Ajay; Levy, Mathew R; Mengistu, Andenet; Hoskins, Michael H; El-Chami, Mikhael F; Lloyd, Michael S; Leon, Angel R; Langberg, Jonathan J; Delurgio, David B

    2015-12-01

    St. Jude Riata/Riata ST defibrillator leads (St. Jude Medical, Sylmar, CA, USA) were recalled by the Food and Drug Administration in 2011 for an increased rate of failure. More than 227,000 leads were implanted and at least 79,000 patients still have active Riata leads. Studies have examined clinical predictors of lead failure in Riata leads, but none have addressed the effect of implantable cardioverter defibrillator (ICD) generator exchange on lead failure. The purpose of this study is to assess the effect of ICD generator exchange on the rate of electrical failure in the Riata lead at 1 year. A retrospective chart review was conducted in patients who underwent implantation of a Riata/Riata ST lead at one center. Patients with a functioning Riata lead (with/without externalized conductor) at the time of ICD exchange were compared to controls with Riata leads implanted for a comparable amount of time who did not undergo generator replacement. Riata leads were implanted in 1,042 patients prior to the recall and 153 of these patients underwent generator exchange without lead replacement. Conductor externalization was noted in 21.5% of Riata leads in the ICD exchange cohort, which was not different from the control group (19.2%; P = 0.32). Two leads failed in the first year after generator replacement (1.5%) which did not significantly differ from the control group (2.0%; P = 0.57). At change-out, 54% received a commanded shock (18.6 ± 0.9 J) that did not result in any change in the high-voltage lead impedance (46.1 ± 1.1 ohms). Conductor externalization was seen frequently in our cohort of patients. ICD generator exchange did not accelerate the rate of Riata lead failure at 1 year. Although both the control and the change-out cohorts failed at a rate much greater than nonrecalled leads, generator exchange did not appear to add to the problem. ©2015 Wiley Periodicals, Inc.

  14. MODELING THE GAMMA-RAY EMISSION IN THE GALACTIC CENTER WITH A FADING COSMIC-RAY ACCELERATOR

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

    Liu, Ruo-Yu; Wang, Xiang-Yu; Prosekin, Anton

    2016-12-20

    Recent HESS observations of the ∼200 pc scale diffuse gamma-ray emission from the central molecular zone (CMZ) suggest the presence of a PeV cosmic-ray accelerator (PeVatron) located in the inner 10 pc region of the Galactic center. Interestingly, the gamma-ray spectrum of the point-like source (HESS J1745-290) in the Galactic center shows a cutoff at ∼10 TeV, implying a cutoff around 100 TeV in the cosmic-ray proton spectrum. Here we propose that the gamma-ray emission from the inner and the outer regions may be explained self-consistently by run-away protons from a single yet fading accelerator. In this model, gamma-rays frommore » the CMZ region are produced by protons injected in the past, while gamma-rays from the inner region are produced by protons injected more recently. We suggest that the blast wave formed in a tidal disruption event (TDE) caused by the supermassive black hole (Sgr A*) could serve as such a fading accelerator. With typical parameters of the TDE blast wave, gamma-ray spectra of both the CMZ region and HESS J1745-290 can be reproduced simultaneously. Meanwhile, we find that the cosmic-ray energy density profile in the CMZ region may also be reproduced in the fading accelerator model when appropriate combinations of the particle injection history and the diffusion coefficient of cosmic rays are adopted.« less

  15. Childhood lead poisoning and the new Centers for Disease Control and Prevention guidelines for lead exposure.

    PubMed

    Schnur, Julie; John, Rita Marie

    2014-05-01

    This article will give a brief history, review the latest guidelines, discuss risk factors and sources, and discuss screening, diagnosis, and management of lead poisoning in children. Additionally, the role of the nurse practitioner (NP) caring for children will be reviewed. Review of published literature on lead poisoning and the 2012 lead prevention guidelines of the Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP) of the Centers for Disease Control and Prevention (CDC). While lead poisoning levels have decreased over the past several decades, newer research has shown that even low levels of lead in the blood can have negative effects on children's intelligence and neurodevelopment. As a result, ACCLPP of the CDC issued new, stricter lead prevention guidelines in 2012. Lead exposure and lead poisoning are pediatric public health risks. Studies have shown that no level of lead is considered safe, and the emphasis has shifted to primary prevention of lead exposure. Despite the focus on primary prevention, the NP must remain vigilant in history taking, exploring risk factors, and screening children in order to assure the best possible outcome. ©2014 The Author(s) ©2014 American Association of Nurse Practitioners.

  16. The Status of Turkish Accelerator Center Test Facility

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

    Yavas, Oe.

    2007-04-23

    Recently, conceptual design of Turkic Accelerator Center (TAC) proposal was completed. Main goal of this proposal is a charm factory that consists of a linac-ring type electron-positron collider. In addition, synchrotron radiation from the positron ring and free electron laser from the electron linac are proposed. The project related with this proposal has been accepted by Turkish government. It is planned that the Technical Design Report of TAC will have been written in next three years. In this period, an infrared oscillator free electron laser (IR FEL) will be constructed as a test facility for TAC. 20 and 50 MeVmore » electron energies will be used to obtain infra red free electron laser. The main parameters of the electron linac, the optical cavities and the free electron laser were determined. The possible use of obtained laser beam in basic and applied research areas such as biotechnology, nanotechnology, semiconductors and photo chemistry were stated.« less

  17. Current Lead Design for the Accelerator Project for Upgrade of LHC

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

    Brandt, Jeffrey S.; Cheban, Sergey; Feher, Sandor

    2010-01-01

    The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. In collaboration with Brookhaven National Laboratory, Fermilab is developing sub-systems for an upgrade of the LHC final focus magnet systems. A concept of main and auxiliary helium flow was developed that allows the superconductor to remain cold while the lead body warms up to prevent upper section frosting. The auxiliary flow will subsequently cool the thermal shields of the feed box and the transmission line cryostats. A thermal analysis of the current lead central heat exchangemore » section was performed using analytic and FEA techniques. A method of remote soldering was developed that allows the current leads to be field replaceable. The remote solder joint was designed to be made without flux or additional solder, and able to be remade up to ten full cycles. A method of upper section attachment was developed that allows high pressure sealing of the helium volume. Test fixtures for both remote soldering and upper section attachment for the 13 kA lead were produced. The cooling concept, thermal analyses, and test results from both remote soldering and upper section attachment fixtures are presented.« less

  18. The ADVANCE network: accelerating data value across a national community health center network

    PubMed Central

    DeVoe, Jennifer E; Gold, Rachel; Cottrell, Erika; Bauer, Vance; Brickman, Andrew; Puro, Jon; Nelson, Christine; Mayer, Kenneth H; Sears, Abigail; Burdick, Tim; Merrell, Jonathan; Matthews, Paul; Fields, Scott

    2014-01-01

    The ADVANCE (Accelerating Data Value Across a National Community Health Center Network) clinical data research network (CDRN) is led by the OCHIN Community Health Information Network in partnership with Health Choice Network and Fenway Health. The ADVANCE CDRN will ‘horizontally’ integrate outpatient electronic health record data for over one million federally qualified health center patients, and ‘vertically’ integrate hospital, health plan, and community data for these patients, often under-represented in research studies. Patient investigators, community investigators, and academic investigators with diverse expertise will work together to meet project goals related to data integration, patient engagement and recruitment, and the development of streamlined regulatory policies. By enhancing the data and research infrastructure of participating organizations, the ADVANCE CDRN will serve as a ‘community laboratory’ for including disadvantaged and vulnerable patients in patient-centered outcomes research that is aligned with the priorities of patients, clinics, and communities in our network. PMID:24821740

  19. Implementing Accelerated Schools in New Orleans: The Satellite Center Project as an Agent of Change.

    ERIC Educational Resources Information Center

    Miron, Louis F.; And Others

    An overview is provided of the Accelerated Schools Project (ASP) as implemented in one urban elementary school in New Orleans, emphasizing the role of the University of New Orleans Satellite Center. The present student population of the school studied is 405 students in grades pre-kindergarten through six. The ASP is a non-traditional strategy for…

  20. Levels of blood lead in Griffon vultures from a Wildlife Rehabilitation Center in Spain.

    PubMed

    González, Fernando; López, Irene; Suarez, Laura; Moraleda, Virginia; Rodríguez, Casilda

    2017-09-01

    Lead is considered a highly toxic contaminant with important impacts to bird wildlife. Griffon vultures (Gyps fulvus) are a sensitive indicator of the level of environmental contamination due to their position at the top of the food chain and their dependence on human activities. The aim of this study was to assess susceptibility to lead intoxication in Griffon vultures admitted to Wildlife Rehabilitation Centers (WRC), measuring blood lead levels and determining if blood lead concentrations are related to clinical signs, hematological, biochemical or radiographic findings. Also, the influence of age, gender, body condition, season and primary cause of admission were evaluated. This study was realized in all Griffon vultures admitted during a period of one year in the Rehabilitation Center GREFA. Blood lead levels are measured by using anodic stripping voltammetry. In Griffon vultures, we observed that 26% of the analyzed birds presented lead levels above 20µg/dL with 74% below 20µg/dL ([Pb] <20 =9.34±5.60µg/dL). In our study, statistically significant differences were found for lead according to sex, season of admission to the center and body condition. A negative correlation was found between levels of metal and hematocrit. No association was found between clinical signs and blood lead levels in Griffon vultures, except for digestive signs as stasis and weight loss. On numerous occasions, the intoxication in this specie is related to ingestion of lead ammunition; however, we have not detected radiographic lead in our vultures. Compared with other studies, we generally found low levels of lead in blood of Griffon vultures but the blood of all birds admitted to WRC presented detectable lead concentrations. This species apparently presents a higher sensibility to the toxic effects of this metal than that described by other authors. It have been observed that there is some evidence that suggests that subclinical levels of lead could be related with a

  1. The Dust Accelerator Facility of the Colorado Center for Lunar Dust and Atmospheric Studies

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

    Horanyi, M.; Colette, A.; Drake, K.

    2011-11-29

    The NASA Lunar Institute's Colorado Center for Lunar Dust and Atmospheric Studies has recently completed the construction of a new experimental facility to study hypervelocity dust impacts. The installation includes a 3 MV Pelletron, accelerating small particles in the size range of 0.1 to few microns to velocities in the range of 1 to 100 km/s. Here we report the capabilities of our facility, and the results of our first experiments.

  2. High blood lead levels are associated with lead concentrations in households and day care centers attended by Brazilian preschool children.

    PubMed

    da Rocha Silva, Júlia Prestes; Salles, Fernanda Junqueira; Leroux, Isabelle Nogueira; da Silva Ferreira, Ana Paula Sacone; da Silva, Agnes Soares; Assunção, Nilson Antonio; Nardocci, Adelaide Cassia; Sayuri Sato, Ana Paula; Barbosa, Fernando; Cardoso, Maria Regina Alves; Olympio, Kelly Polido Kaneshiro

    2018-08-01

    A previous study observed high blood lead levels (BLL) in preschool children attending 50 day care centers (DCC) in São Paulo, Brazil. To identify whether lead levels found in both homes and DCC environments are associated with high blood lead levels. Children attending 4 DCCs, quoted here as NR, VA, PS and PF, were divided into two groups according to BLL: high exposure (HE: ≥13.9 μg/dL; 97.5 percentile of the 2013 year sample) and low exposure (LE: <5 μg/dL). For in situ lead measurements (lead paint mode: mg/cm 2 and ROHS mode: μg/g) in the children's households and in the DCC environments, a field portable X-ray-fluorescence analyzer was used. Multiple logistic regressions were performed to control for confounding factors. Odds ratios were adjusted for age, sex, day care center's measured lead, and tobacco. In an NR DCC building, 33.8% of the measurements had lead levels >600 μg/g, whereas such levels were observed in 77.1% of NR playground measurements. In VA DCC, 22% and 23% of the measurements in the building and in the playgrounds had levels higher than 600 μg/g, respectively. The percentage of high lead levels in the children's houses of the LE group was 5.9% (95% CI: 4.3-7.6%) and 13.2 (95% CI: 8.3-18.0%) in the HE group. Moreover, a significant association was found between high BLLs and lead levels found both in households and DCCs (p < 0.001). Most of the high lead measurements were found in tiles and playground equipment. Lead exposure estimated from the DCCs, where children spend about 10 h/day, can be as relevant as their household exposure. Therefore, public authorities should render efforts to provide a rigorous surveillance for lead-free painting supplies and for all objects offered to children. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Preventing Lead Poisoning in Young Children: A Statement by the Center for Disease Control.

    ERIC Educational Resources Information Center

    Center for Disease Control (DHEW/PHS), Atlanta, GA.

    The purpose of this statement by the Center for Disease Control is to reflect new data available from clinical, epidemiological and experimental studies by making revised recommendations regarding the screening, diagnosis, treatment, and followup of children with undue lead absorption and lead poisoning. The ultimate preventive goal is…

  4. Preventing Lead Poisoning in Young Children. A Statement by the Centers for Disease Control.

    ERIC Educational Resources Information Center

    Centers for Disease Control (DHHS/PHS), Atlanta, GA.

    This document is the fourth revision of a statement by the Centers for Disease Control. Introductory and background chapters present data that indicate significant adverse effects of lead levels in children's blood that were previously believed to be safe. Other chapters discuss: (1) sources of lead exposure, including paint, soil and dust, and…

  5. New evaporator station for the center for accelerator target science

    NASA Astrophysics Data System (ADS)

    Greene, John P.; Labib, Mina

    2018-05-01

    As part of an equipment grant provided by DOE-NP for the Center for Accelerator Target Science (CATS) initiative, the procurement of a new, electron beam, high-vacuum deposition system was identified as a priority to insure reliable and continued availability of high-purity targets. The apparatus is designed to contain TWO electron beam guns; a standard 4-pocket 270° geometry source as well as an electron bombardment source. The acquisition of this new system allows for the replacement of TWO outdated and aging vacuum evaporators. Also included is an additional thermal boat source, enhancing our capability within this deposition unit. Recommended specifications for this system included an automated, high-vacuum pumping station, a deposition chamber with a rotating and heated substrate holder for uniform coating capabilities and incorporating computer-controlled state-of-the-art thin film technologies. Design specifications, enhanced capabilities and the necessary mechanical modifications for our target work are discussed.

  6. NINR Centers of Excellence: A logic model for sustainability, leveraging resources and collaboration to accelerate cross-disciplinary science

    PubMed Central

    Dorsey, Susan G.; Schiffman, Rachel; Redeker, Nancy S.; Heitkemper, Margaret; McCloskey, Donna Jo; Weglicki, Linda S.; Grady, Patricia A.

    2014-01-01

    The NINR Centers of Excellence program is a catalyst enabling institutions to develop infrastructure and administrative support for creating cross-disciplinary teams that bring multiple strategies and expertise to bear on common areas of science. Centers are increasingly collaborative with campus partners and reflect an integrated team approach to advance science and promote the development of scientists in these areas. The purpose of this paper is to present a NINR Logic Model for Center Sustainability. The components of the logic model were derived from the presentations and robust discussions at the 2013 NINR Center Directors’ meeting focused on best practices for leveraging resources and collaboration as methods to promote center sustainability. Collaboration through development and implementation of cross-disciplinary research teams is critical to accelerate the generation of new knowledge for solving fundamental health problems. Sustainability of centers as a long-term outcome beyond the initial funding can be enhanced by thoughtful planning of inputs, activities, and leveraging resources across multiple levels. PMID:25085328

  7. Angular Acceleration without Torque?

    ERIC Educational Resources Information Center

    Kaufman, Richard D.

    2012-01-01

    Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

  8. 3 MV hypervelocity dust accelerator at the Colorado Center for Lunar Dust and Atmospheric Studies.

    PubMed

    Shu, Anthony; Collette, Andrew; Drake, Keith; Grün, Eberhard; Horányi, Mihály; Kempf, Sascha; Mocker, Anna; Munsat, Tobin; Northway, Paige; Srama, Ralf; Sternovsky, Zoltán; Thomas, Evan

    2012-07-01

    A hypervelocity dust accelerator for studying micrometeorite impacts has been constructed at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) at the University of Colorado. Based on the Max-Planck-Institüt für Kernphysik (MPI-K) accelerator, this accelerator is capable of emitting single particles of a specific mass and velocity selected by the user. The accelerator consists of a 3 MV Pelletron generator with a dust source, four image charge pickup detectors, and two interchangeable target chambers: a large high-vacuum test bed and an ultra-high vacuum impact study chamber. The large test bed is a 1.2 m diameter, 1.5 m long cylindrical vacuum chamber capable of pressures as low as 10(-7) torr while the ultra-high vacuum chamber is a 0.75 m diameter, 1.1 m long chamber capable of pressures as low as 10(-10) torr. Using iron dust of up to 2 microns in diameter, final velocities have been measured up to 52 km/s. The spread of the dust particles and the effect of electrostatic focusing have been measured using a long exposure CCD and a quartz target. Furthermore, a new technique of particle selection is being developed using real time digital filtering techniques. Signals are digitized and then cross-correlated with a shaped filter, resulting in a suppressed noise floor. Improvements over the MPI-K design, which include a higher operating voltage and digital filtering for detection, increase the available parameter space of dust emitted by the accelerator. The CCLDAS dust facility is a user facility open to the scientific community to assist with instrument calibrations and experiments.

  9. Flow acceleration structure of Aurelia aurita: implications on propulsion

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Tae; Piper, Matthew; Chamorro, Leonardo P.

    2017-11-01

    The jetting and paddling mechanisms used by Aurelia aurita jellyfish allows for one of the most efficient propulsion among other metazoans. Characterization of the induced flow acceleration is critical to uncover distinctive patterns. We found four acceleration structures using 3D measurements of body and flow dynamics in Lagrangian frame of reference. Two intense structures occur near the bell margin and are generated by paddling; the other two around the center of the jellyfish and half magnitude are a result of jetting. Their interaction leads to the maximum flow velocity in the middle of the relaxation, where relatively straight flow trajectories occur. The jellyfish achieves an efficient relaxation by generating flow deceleration with minor body deceleration.

  10. Electrical Engineering in Los Alamos Neutron Science Center Accelerator

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

    Silva, Michael James

    The field of electrical engineering plays a significant role in particle accelerator design and operations. Los Alamos National Laboratories LANSCE facility utilizes the electrical energy concepts of power distribution, plasma generation, radio frequency energy, electrostatic acceleration, signals and diagnostics. The culmination of these fields produces a machine of incredible potential with uses such as isotope production, neutron spallation, neutron imaging and particle analysis. The key isotope produced in LANSCE isotope production facility is Strontium-82 which is utilized for medical uses such as cancer treatment and positron emission tomography also known as PET scans. Neutron spallation is one of the verymore » few methods used to produce neutrons for scientific research the other methods are natural decay of transuranic elements from nuclear reactors. Accelerator produce neutrons by accelerating charged particles into neutron dense elements such as tungsten imparting a neutral particle with kinetic energy, this has the benefit of producing a large number of neutrons as well as minimizing the waste generated. Utilizing the accelerator scientist can gain an understanding of how various particles behave and interact with matter to better understand the natural laws of physics and the universe around us.« less

  11. An evaluation of lead contamination in plastic toys collected from day care centers in the Las Vegas Valley, Nevada, USA.

    PubMed

    Greenway, Joseph A; Gerstenberger, Shawn

    2010-10-01

    Childhood exposure to environmental lead continues to be a major health concern. This study examined lead content within the plastic of children's toys collected from licensed day care centers in the Las Vegas valley, Nevada. It was hypothesized that the use of lead as a plastics stabilizer would result in elevated lead (≥600 ppm) in polyvinyl chloride plastics (PVC) compared to non-PVC plastics. It was also hypothesized that, due to the use of lead chromate as a coloring agent, yellow toys would contain higher concentrations of lead (≥600 ppm) than toys of other colors. Toy samples were limited to those found in day care centers in Las Vegas, Nevada. 10 day care centers were visited and approximately 50 toy samples were taken from each center. Of the 535 toys tested, 29 contained lead in excess of 600 parts per million (ppm). Of those 29 toys, 20 were PVC and 17 were yellow. Both of the two hypotheses were strongly supported by the data.

  12. Nonthermally dominated electron acceleration during magnetic reconnection in a low- β plasma

    DOE PAGES

    Li, Xiaocan; Guo, Fan; Li, Hui; ...

    2015-09-24

    By means of fully kinetic simulations, we investigate electron acceleration during magnetic reconnection in a nonrelativistic proton–electron plasma with conditions similar to solar corona and flares. We demonstrate that reconnection leads to a nonthermally dominated electron acceleration with a power-law energy distribution in the nonrelativistic low-β regime but not in the high-β regime, where β is the ratio of the plasma thermal pressure and the magnetic pressure. The accelerated electrons contain most of the dissipated magnetic energy in the low-β regime. A guiding-center current description is used to reveal the role of electron drift motions during the bulk nonthermal energization.more » We find that the main acceleration mechanism is a Fermi-type acceleration accomplished by the particle curvature drift motion along the electric field induced by the reconnection outflows. Although the acceleration mechanism is similar for different plasma β, low-β reconnection drives fast acceleration on Alfvénic timescales and develops power laws out of thermal distribution. Thus, the nonthermally dominated acceleration resulting from magnetic reconnection in low-β plasma may have strong implications for the highly efficient electron acceleration in solar flares and other astrophysical systems.« less

  13. Accelerating Energy Efficiency in Indian Data Centers. Final Report for Phase I Activities

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

    Ganguly, Suprotim; Raje, Sanyukta; Kumar, Satish

    This report documents Phase 1 of the “Accelerating Energy Efficiency in Indian Data Centers” initiative to support the development of an energy efficiency policy framework for Indian data centers. The initiative is being led by the Confederation of Indian Industry (CII), in collaboration with Lawrence Berkeley National Laboratory (LBNL)-U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, and under the guidance of Bureau of Energy Efficiency (BEE). It is also part of the larger Power and Energy Efficiency Working Group of the US-India Bilateral Energy Dialogue. The initiative consists of two phases: Phase 1 (November 2014 – Septembermore » 2015) and Phase 2 (October 2015 – September 2016).« less

  14. Safety and Efficacy of Transvenous Lead Extraction Utilizing the Evolution Mechanical Lead Extraction System: A Single-Center Experience.

    PubMed

    Sharma, Saumya; Ekeruo, Ijeoma A; Nand, Nikita P; Sundara Raman, Ajay; Zhang, Xu; Reddy, Sunil K; Hariharan, Ramesh

    2018-02-01

    The goal of this study is to assess the safety and efficacy of mechanical lead extraction utilizing the Evolution system. Compared with other techniques commonly used for lead extraction, data regarding the safety and efficacy of mechanical lead extraction using the Evolution system is limited and needs further evaluation. Between June 1, 2009 and September 30, 2016, we retrospectively analyzed 400 consecutive patients who exclusively underwent mechanical lead extraction utilizing the Evolution system. A total of 400 patients underwent mechanical lead extraction of 683 leads. Mean age of extracted leads was 6.77 ± 4.42 years (range 1 to 31 years). The extracted device system was an implantable cardioverter-defibrillator in 274 patients (68.5%) and a pacemaker system in 126 patients (31.5%). Complete lead removal rate was 97% with a clinical success rate of 99.75%. Incomplete lead removal with <4-cm remnant was associated with older leads (lead age >8 years). Failure to achieve clinical success was noted in 1 patient (0.25%). Cardiac papillary avulsion, system-related infection, and cardiac tamponade were the major complications noted in 6 patients (1.5%). Minor complications were encountered in 24 patients (6%), of which hematoma requiring evacuation was the most common minor complication. There were no patient deaths. In our single-center study, lead extractions utilizing the Evolution mechanical lead extraction system were safe and effective and resulted in high clinical and procedural success, with low complication rates and no fatalities. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  15. Shear banding leads to accelerated aging dynamics in a metallic glass

    NASA Astrophysics Data System (ADS)

    Küchemann, Stefan; Liu, Chaoyang; Dufresne, Eric M.; Shin, Jeremy; Maaß, Robert

    2018-01-01

    Traditionally, strain localization in metallic glasses is related to the thickness of the shear defect, which is confined to the nanometer scale. Using site-specific x-ray photon correlation spectroscopy, we reveal significantly accelerated relaxation dynamics around a shear band in a metallic glass at a length scale that is orders of magnitude larger than the defect itself. The relaxation time in the shear-band vicinity is up to ten times smaller compared to the as-cast matrix, and the relaxation dynamics occurs in a characteristic three-stage aging response that manifests itself in the temperature-dependent shape parameter known from classical stretched exponential relaxation dynamics of disordered materials. We demonstrate that the time-dependent correlation functions describing the aging at different temperatures can be captured and collapsed using simple scaling functions. These insights highlight how a ubiquitous nanoscale strain-localization mechanism in metallic glasses leads to a fundamental change of the relaxation dynamics at the mesoscale.

  16. Radical Acceleration

    ERIC Educational Resources Information Center

    Gross, Miraca U. M.; Van Vliet, Helen E.

    2005-01-01

    Research has found that teachers' objections to accelerating gifted students are mainly based on a fear that acceleration will lead to social or emotional damage. Ironically, it is the academic and emotional maturity which characterizes intellectually gifted students, coupled with their high levels of academic achievement, which makes them such…

  17. Ames Research Center FY 2000 Implementation Plan: Leading Technology into the New Millennium

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This document presents the implementation plan for Ames Research Center (ARC) within the overall framework of the NASA Strategic Plan. It describes how ARC intends to implement its Center of Excellence responsibilities, Agency assigned missions, Agency and Enterprise lead programs, and other roles in support of NASA's vision and mission. All Federal agencies are required by the 1993 Government Performance and Results Act to implement a long-term strategic planning process that includes measurable outcomes and strict accountability. At NASA, this planning process is shaped by the Space Act of 1958, annual appropriations, and other external mandates, as well as by customer requirements. The resulting Strategic Plan sets the overall architecture for what we do, identifies who our customers are, and directs where we are going and why. The Strategic Plan is the basis upon which decisions regarding program implementation and resource deployment are made. Whereas the strategic planning process examines the long-term direction of the organization and identifies a specific set of goals, the implementation planning process examines the detailed performance of the organization and allocates resources toward meeting these goals. It is the purpose of this implementation document to provide the connection between the NASA Strategic Plan and the specific programs and support functions that ARC employees perform. This connection flows from the NASA Strategic Plan, through the various Strategic Enterprise plans to the ARC Center of Excellence, primary missions, Lead Center programs, program support responsibilities, and ultimately, to the role of the individual ARC employee.

  18. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  19. Growth of Integrative Medicine at Leading Cancer Centers Between 2009 and 2016: A Systematic Analysis of NCI-Designated Comprehensive Cancer Center Websites.

    PubMed

    Yun, Hyeongjun; Sun, Lingyun; Mao, Jun J

    2017-11-01

    Cancer centers have increasingly offered integrative medicine therapies in response to their patients' unmet needs. We evaluated the growth of integrative medicine in leading academic cancer centers in the United States as reflected by their public-facing websites. We performed a systematic review of 45 National Cancer Institute (NCI)-designated comprehensive cancer center websites. Two researchers independently evaluated whether the websites provided information regarding integrative medicine modalities and, if so, whether the services were provided in the same health system. They compared the proportion of cancer centers providing the information on each modality in 2016 with the data from the prior study in 2009. The most common integrative medicine therapies mentioned on the 45 NCI-designated comprehensive cancer center websites were exercise (97.8%) and acupuncture and meditation (88.9% each), followed by yoga (86.7%), massage (84.4%), and music therapy (82.2%). The majority of the websites also provided information on nutrition (95.6%), dietary supplements (93.3%), and herbs (88.9%). The most common therapies offered in the health systems were acupuncture/massage (73.3% each), meditation/yoga (68.9% each), and consultations about nutrition (91.1%), dietary supplements (84.4%), and herbs (66.7%). Compared with 2009, there was a statistically significant increase in the number of websites mentioning acupuncture, dance therapy, healing touch, hypnosis, massage, meditation, Qigong, and yoga (all P < .05). Leading US cancer centers increasingly present integrative medicine content on their websites, and the majority of them provide these services to patients in the same health systems. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  20. Effective Teaching in Accelerated Learning Programs

    ERIC Educational Resources Information Center

    Boyd, Drick

    2004-01-01

    According to Wlodkowski (2003), "accelerated learning programs are one of the fastest growing transformations in higher education" (p. 5). The Center for the Study of Accelerated Learning at Regis University has documented at least 250 colleges or universities that offer accelerated learning programs for working adults. By definition, accelerated…

  1. Center for Defect Physics - Energy Frontier Research Center (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema

    Stocks, G. Malcolm (Director, Center for Defect Physics in Structural Materials); CDP Staff

    2017-12-09

    'Center for Defect Physics - Energy Frontier Research Center' was submitted by the Center for Defect Physics (CDP) to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. CDP is directed by G. Malcolm Stocks at Oak Ridge National Laboratory, and is a partnership of scientists from nine institutions: Oak Ridge National Laboratory (lead); Ames Laboratory; Brown University; University of California, Berkeley; Carnegie Mellon University; University of Illinois, Urbana-Champaign; Lawrence Livermore National Laboratory; Ohio State University; and University of Tennessee. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.

  2. Center for Defect Physics - Energy Frontier Research Center (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

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

    Stocks, G. Malcolm; Ice, Gene

    "Center for Defect Physics - Energy Frontier Research Center" was submitted by the Center for Defect Physics (CDP) to the "Life at the Frontiers of Energy Research" video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. CDP is directed by G. Malcolm Stocks at Oak Ridge National Laboratory, and is a partnership of scientists from eight institutions: Oak Ridge National Laboratory (lead); Ames Laboratory; University of California, Berkeley; Carnegie Mellon University; University of Illinois, Urbana-Champaign; Ohio State University;more » University of Georgia and University of Tennessee. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.« less

  3. Shear banding leads to accelerated aging dynamics in a metallic glass

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

    Küchemann, Stefan; Liu, Chaoyang; Dufresne, Eric M.

    Traditionally, strain localization in metallic glasses is related to the thickness of the shear defect, which is confined to the nanometer scale. In this study, using site-specific x-ray photon correlation spectroscopy (XPCS), we reveal significantly accelerated relaxation dynamics around a shear band in a metallic glass at a length scale that is orders of magnitude larger than the defect itself. The relaxation time in the shear-band vicinity is up to ten-times smaller compared to the as-cast matrix, and the relaxation dynamics occurs in a characteristic three-stage aging response that manifests itself in the temperature-dependent shape parameter known from classical stretchedmore » exponential relaxation dynamics of disordered materials. We demonstrate that the time-dependent correlation functions describing the aging at different temperatures can be captured and collapsed using simple scaling functions. Finally, these insights highlight how an ubiquitous nano-scale strain-localization mechanism in metallic glasses leads to a fundamental change of the relaxation dynamics at the mesoscale.« less

  4. Shear banding leads to accelerated aging dynamics in a metallic glass

    DOE PAGES

    Küchemann, Stefan; Liu, Chaoyang; Dufresne, Eric M.; ...

    2018-01-11

    Traditionally, strain localization in metallic glasses is related to the thickness of the shear defect, which is confined to the nanometer scale. In this study, using site-specific x-ray photon correlation spectroscopy (XPCS), we reveal significantly accelerated relaxation dynamics around a shear band in a metallic glass at a length scale that is orders of magnitude larger than the defect itself. The relaxation time in the shear-band vicinity is up to ten-times smaller compared to the as-cast matrix, and the relaxation dynamics occurs in a characteristic three-stage aging response that manifests itself in the temperature-dependent shape parameter known from classical stretchedmore » exponential relaxation dynamics of disordered materials. We demonstrate that the time-dependent correlation functions describing the aging at different temperatures can be captured and collapsed using simple scaling functions. Finally, these insights highlight how an ubiquitous nano-scale strain-localization mechanism in metallic glasses leads to a fundamental change of the relaxation dynamics at the mesoscale.« less

  5. Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation.

    PubMed

    Nataraj, Raviraj; Audu, Musa L; Triolo, Ronald J

    2012-05-06

    The purpose of this study was to determine the comparative effectiveness of feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM acceleration feedback alone, and combined joint kinematics and COM acceleration feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS), and the resulting joint kinematics and COM acceleration data was analyzed. Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics feedback and 35% for COM acceleration feedback. Pilot data indicated that COM acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Overall, COM acceleration feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small number of inputs required.

  6. Should the Centers for Disease Control and Prevention's childhood lead poisoning intervention level be lowered?

    PubMed

    Bernard, Susan M

    2003-08-01

    The US Centers for Disease Control and Prevention (CDC) in 1991 chose 10 micro g/dL as an initial screening level for lead in children's blood. Current data on health risks and intervention options do not support generally lowering that level, but federal lead poisoning prevention efforts can be improved by revising the follow-up testing schedule for infants aged 1 year or less with blood lead levels of 5 micro g/dL or higher; universal education about lead exposure risks; universal administration of improved, locally validated risk-screening questionnaires; enhanced compliance with targeted screening recommendations and federal health program requirements; and development by regulatory agencies of primary prevention criteria that do not use the CDC's intervention level as a target "safe" lead exposure.

  7. Joint Center for Artificial Photosynthesis

    ScienceCinema

    Koval, Carl; Lee, Kenny; Houle, Frances; Lewis, Na

    2018-05-30

    The Joint Center for Artificial Photosynthesis (JCAP) is the nation's largest research program dedicated to the development of an artificial solar-fuel generation technology. Established in 2010 as a U.S. Department of Energy (DOE) Energy Innovation Hub, JCAP aims to find a cost-effective method to produce fuels using only sunlight, water, and carbon dioxide as inputs. JCAP brings together more than 140 top scientists and researchers from the California Institute of Technology and its lead partner, Berkeley Lab, along with collaborators from the SLAC National Accelerator Laboratory, and the University of California campuses at Irvine and San Diego.

  8. Joint Center for Artificial Photosynthesis

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

    Koval, Carl; Lee, Kenny; Houle, Frances

    2013-12-10

    The Joint Center for Artificial Photosynthesis (JCAP) is the nation's largest research program dedicated to the development of an artificial solar-fuel generation technology. Established in 2010 as a U.S. Department of Energy (DOE) Energy Innovation Hub, JCAP aims to find a cost-effective method to produce fuels using only sunlight, water, and carbon dioxide as inputs. JCAP brings together more than 140 top scientists and researchers from the California Institute of Technology and its lead partner, Berkeley Lab, along with collaborators from the SLAC National Accelerator Laboratory, and the University of California campuses at Irvine and San Diego.

  9. Comparing joint kinematics and center of mass acceleration as feedback for control of standing balance by functional neuromuscular stimulation

    PubMed Central

    2012-01-01

    Background The purpose of this study was to determine the comparative effectiveness of feedback control systems for maintaining standing balance based on joint kinematics or total body center of mass (COM) acceleration, and assess their clinical practicality for standing neuroprostheses after spinal cord injury (SCI). Methods In simulation, controller performance was measured according to the upper extremity effort required to stabilize a three-dimensional model of bipedal standing against a variety of postural disturbances. Three cases were investigated: proportional-derivative control based on joint kinematics alone, COM acceleration feedback alone, and combined joint kinematics and COM acceleration feedback. Additionally, pilot data was collected during external perturbations of an individual with SCI standing with functional neuromuscular stimulation (FNS), and the resulting joint kinematics and COM acceleration data was analyzed. Results Compared to the baseline case of maximal constant muscle excitations, the three control systems reduced the mean upper extremity loading by 51%, 43% and 56%, respectively against external force-pulse perturbations. Controller robustness was defined as the degradation in performance with increasing levels of input errors expected with clinical deployment of sensor-based feedback. At error levels typical for body-mounted inertial sensors, performance degradation due to sensor noise and placement were negligible. However, at typical tracking error levels, performance could degrade as much as 86% for joint kinematics feedback and 35% for COM acceleration feedback. Pilot data indicated that COM acceleration could be estimated with a few well-placed sensors and efficiently captures information related to movement synergies observed during perturbed bipedal standing following SCI. Conclusions Overall, COM acceleration feedback may be a more feasible solution for control of standing with FNS given its superior robustness and small

  10. Principal Investigator Microgravity Services Role in ISS Acceleration Data Distribution

    NASA Technical Reports Server (NTRS)

    McPherson, Kevin

    1999-01-01

    Measurement of the microgravity acceleration environment on the International Space Station will be accomplished by two accelerometer systems. The Microgravity Acceleration Measurement System will record the quasi-steady microgravity environment, including the influences of aerodynamic drag, vehicle rotation, and venting effects. Measurement of the vibratory/transient regime comprised of vehicle, crew, and equipment disturbances will be accomplished by the Space Acceleration Measurement System-II. Due to the dynamic nature of the microgravity environment and its potential to influence sensitive experiments, Principal Investigators require distribution of microgravity acceleration in a timely and straightforward fashion. In addition to this timely distribution of the data, long term access to International Space Station microgravity environment acceleration data is required. The NASA Glenn Research Center's Principal Investigator Microgravity Services project will provide the means for real-time and post experiment distribution of microgravity acceleration data to microgravity science Principal Investigators. Real-time distribution of microgravity environment acceleration data will be accomplished via the World Wide Web. Data packets from the Microgravity Acceleration Measurement System and the Space Acceleration Measurement System-II will be routed from onboard the International Space Station to the NASA Glenn Research Center's Telescience Support Center. Principal Investigator Microgravity Services' ground support equipment located at the Telescience Support Center will be capable of generating a standard suite of acceleration data displays, including various time domain and frequency domain options. These data displays will be updated in real-time and will periodically update images available via the Principal Investigator Microgravity Services web page.

  11. Lead-Time Bias and Interhospital Transfer after Injury: Trauma Center Admission Vital Signs Underpredict Mortality in Transferred Trauma Patients.

    PubMed

    Holena, Daniel N; Wiebe, Douglas J; Carr, Brendan G; Hsu, Jesse Y; Sperry, Jason L; Peitzman, Andrew B; Reilly, Patrick M

    2017-03-01

    Admission physiology predicts mortality after injury, but may be improved by resuscitation before transfer. This phenomenon, which has been termed lead-time bias, may lead to underprediction of mortality in transferred patients and inaccurate benchmarking in centers receiving large numbers of transfer patients. We sought to determine the impact of using vital signs on arrival at the referring center vs on arrival at the trauma center in mortality prediction models for transferred trauma patients. We performed a retrospective cohort study using a state-wide trauma registry including all patients age 16 years or older, with Abbreviated Injury Scale scores ≥ 3, admitted to level I and II trauma centers in Pennsylvania, from 2011 to 2014. The primary outcomes measure was the risk-adjusted association between mortality and interhospital transfer (IHT) when adjusting for physiology (as measured by Revised Trauma Score [RTS]) using the referring hospital arrival vital signs (model 1) compared with trauma center arrival vital signs (model 2). After adjusting for patient and injury factors, IHT was associated with reduced mortality (odds ratio [OR] 0.85; 95% CI 0.77 to 0.93) using the RTS from trauma center admission, but with increased mortality (OR 1.15; 95% CI 1.05 to 1.27) using RTS from the referring hospital. The greater the number of transfer patients seen by a center, the greater the difference in center-level mortality predicted by the 2 models (β -0.044; 95% CI -0.044 to -0.0043; p ≤ 0.001). Trauma center vital signs underestimate mortality in transfer patients and may lead to incorrect estimates of expected mortality. Where possible, benchmarking efforts should use referring hospital vital signs to risk-adjust IHT patients. Copyright © 2016 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  12. Implications of the new Centers for Disease Control and Prevention blood lead reference value.

    PubMed

    Burns, Mackenzie S; Gerstenberger, Shawn L

    2014-06-01

    The Centers for Disease Control and Prevention recently established a new reference value (≥ 5 μg/dL) as the standard for identifying children with elevated blood lead levels (EBLs). At present, 535,000 US children aged 1 to 5 years (2.6%) are estimated to have EBLs according to the new standard, versus 0.8% according to the previous standard (≥ 10 μg/dL). Because EBLs signify the threshold for public health intervention, this new definition increases demands on lead poisoning prevention efforts. Primary prevention has been proven to reduce lead poisoning cases and is also cost effective; however, federal budget cuts threaten the existence of such programs. Protection for the highest-risk children necessitates a reinstatement of federal funding to previous levels.

  13. Pulse - Accelerator Science in Medicine

    Science.gov Websites

    discoveries in particle accelerator science may lead to unexpected applications for medical diagnosis, healing perhaps to new tools for medical science. National laboratories build particle accelerators for physicists

  14. Regional Instrumentation Centers.

    ERIC Educational Resources Information Center

    Cromie, William J.

    1980-01-01

    Focuses on the activities of regional instrumentation centers that utilize the state-of-the-art instruments and methodology in basic scientific research. The emphasis is on the centers involved in mass spectroscopy, magnetic resonance spectroscopy, lasers, and accelerators. (SA)

  15. Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments

    NASA Astrophysics Data System (ADS)

    Chang, J. C.; Lockner, D. A.; Reches, Z.

    2012-12-01

    We simulated the slip of a fault-patch during a large earthquake by rapidly loading an experimental, ring-shaped fault with energy stored in a spinning flywheel. The flywheel abruptly delivers a finite amount of energy by spinning the fault-patch that spontaneously dissipates the energy without operator intervention. We conducted 42 experiments on Sierra White granite (SWG) samples, and 24 experiments on Kasota dolomite (KD) samples. Each experiment starts by spinning a 225 kg disk-shaped flywheel to a prescribed angular velocity. We refer to this experiment as an "earthquake-like slip-event" (ELSE). The strength-evolution in ELSE experiments is similar to the strength-evolution proposed for earthquake models and observed in stick-slip experiments. Further, we found that ELSE experiments are similar to earthquakes in at least three ways: (1) slip driven by the release of a finite amount of stored energy; (2) pattern of fault strength evolution; and (3) seismically observed values, such as average slip, peak-velocity and rise-time. By assuming that the measured slip, D, in ELSE experiments is equivalent to the average slip during an earthquake, we found that ELSE experiments (D = 0.003-4.6 m) correspond to earthquakes in moment-magnitude range of Mw = 4-8. In ELSE experiments, the critical-slip-distance, dc, has mean values of 2.7 cm and 1.2 cm for SWG and KD, that are much shorter than the 1-10 m in steady-state classical experiments in rotary shear systems. We attribute these dc values, to ELSE loading in which the fault-patch is abruptly loaded by impact with a spinning flywheel. Under this loading, the friction-velocity relations are strikingly different from those under steady-state loading on the same rock samples with the same shear system (Reches and Lockner, Nature, 2010). We further note that the slip acceleration in ELSE evolves systematically with fault strength and wear-rate, and that the dynamic weakening is restricted to the period of intense

  16. Naked singularities as particle accelerators. II

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

    Patil, Mandar; Joshi, Pankaj S.; Malafarina, Daniele

    We generalize here our earlier results on particle acceleration by naked singularities. We showed recently [M. Patil and P. S. Joshi, Phys. Rev. D 82, 104049 (2010).] that the naked singularities that form due to the gravitational collapse of massive stars provide a suitable environment where particles could get accelerated and collide at arbitrarily high center-of-mass energies. However, we focused there only on the spherically symmetric gravitational collapse models, which were also assumed to be self-similar. In this paper, we broaden and generalize the result to all gravitational collapse models leading to the formation of a naked singularity as themore » final state of collapse, evolving from a regular initial data, without making any prior restrictive assumptions about the spacetime symmetries such as above. We show that, when the particles interact and collide near the Cauchy horizon, the energy of collision in the center-of-mass frame will be arbitrarily high, thus offering a window to the Planck scale physics. We also consider the issue of various possible physical mechanisms of generation of such very high-energy particles from the vicinity of naked singularity. We then construct a model of gravitational collapse to a timelike naked singularity to demonstrate the working of these ideas, where the pressure is allowed to be negative, but the energy conditions are respected. We show that a finite amount of mass-energy density has to be necessarily radiated away from the vicinity of the naked singularity as the collapse evolves. Therefore, the nature of naked singularities, both at the classical and quantum level, could play an important role in the process of particle acceleration, explaining the occurrence of highly energetic outgoing particles in the vicinity of the Cauchy horizon that participate in extreme high-energy collisions.« less

  17. Laser Accelerator

    DTIC Science & Technology

    2014-09-01

    hollow metal sphere. Voltages of over 10 MV can be reached if used with an insulating gas. Corona discharge limits all electrostatic accelerators to...laser field. Lasers can have strong electric fields with frequencies high enough to avoid corona formation and break- down. The key is to couple the...leading to a spark discharge in the accelerator and thus a breakdown of the electrostatic field [6], [7]. Figure 1.1: Cockroft-Walton cascade generator

  18. The NASA Short-term Prediction Research and Transition (SPoRT) Center: A Collaborative Model for Accelerating Research into Operations

    NASA Technical Reports Server (NTRS)

    Goodman, S. J.; Lapenta, W.; Jedlovec, G.; Dodge, J.; Bradshaw, T.

    2003-01-01

    The NASA Short-term Prediction Research and Transition (SPoRT) Center in Huntsville, Alabama was created to accelerate the infusion of NASA earth science observations, data assimilation and modeling research into NWS forecast operations and decision-making. The principal focus of experimental products is on the regional scale with an emphasis on forecast improvements on a time scale of 0-24 hours. The SPoRT Center research is aligned with the regional prediction objectives of the US Weather Research Program dealing with 0-1 day forecast issues ranging from convective initiation to 24-hr quantitative precipitation forecasting. The SPoRT Center, together with its other interagency partners, universities, and the NASA/NOAA Joint Center for Satellite Data Assimilation, provides a means and a process to effectively transition NASA Earth Science Enterprise observations and technology to National Weather Service operations and decision makers at both the global/national and regional scales. This paper describes the process for the transition of experimental products into forecast operations, current products undergoing assessment by forecasters, and plans for the future.

  19. (Installation of the Vinca Accelerator)

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

    Zucker, A.

    1991-04-22

    I participated in a workshop of the physics with accelerators in Belgrade, Yugoslavia and chaired an advisory committee for the Vinca Accelerator Installation which is currently in progress. Also, I participated in meetings with the Serbian Academy of Sciences and with the Deputy Prime Minister of Serbia concerning the plans and aspirations of the nuclear research center at Vinca.

  20. Acceleration of on-axis and ring-shaped electron beams in wakefields driven by Laguerre-Gaussian pulses

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

    Zhang, Guo-Bo; Key Laboratory for Laser Plasmas; Chen, Min, E-mail: minchen@sjtu.edu.cn, E-mail: yanyunma@126.com

    2016-03-14

    The acceleration of electron beams with multiple transverse structures in wakefields driven by Laguerre-Gaussian pulses has been studied through three-dimensional (3D) particle-in-cell simulations. Under different laser-plasma conditions, the wakefield shows different transverse structures. In general cases, the wakefield shows a donut-like structure and it accelerates the ring-shaped hollow electron beam. When a lower plasma density or a smaller laser spot size is used, besides the donut-like wakefield, a central bell-like wakefield can also be excited. The wake sets in the center of the donut-like wake. In this case, both a central on-axis electron beam and a ring-shaped electron beam aremore » simultaneously accelerated. Further, reducing the plasma density or laser spot size leads to an on-axis electron beam acceleration only. The research is beneficial for some potential applications requiring special pulse beam structures, such as positron acceleration and collimation.« less

  1. Implications of the New Centers for Disease Control and Prevention Blood Lead Reference Value

    PubMed Central

    Burns, Mackenzie S.; Gerstenberger, Shawn L.

    2014-01-01

    The Centers for Disease Control and Prevention recently established a new reference value (≥ 5 μg/dL) as the standard for identifying children with elevated blood lead levels (EBLs). At present, 535 000 US children aged 1 to 5 years (2.6%) are estimated to have EBLs according to the new standard, versus 0.8% according to the previous standard (≥ 10 μg/dL). Because EBLs signify the threshold for public health intervention, this new definition increases demands on lead poisoning prevention efforts. Primary prevention has been proven to reduce lead poisoning cases and is also cost effective; however, federal budget cuts threaten the existence of such programs. Protection for the highest-risk children necessitates a reinstatement of federal funding to previous levels. PMID:24825227

  2. An innovative re-centering SMA-lead damper and its application to steel frame structures

    NASA Astrophysics Data System (ADS)

    Li, Hong-Nan; Liu, Ming-Ming; Fu, Xing

    2018-07-01

    In this paper, an innovative re-centering damper is presented to reduce the residual deflection of civil structures under strong earthquakes. The schematic diagram of the proposed re-centering SMA-lead damper (RSLD) is provided first. Then the mechanical behaviors of all the sub-components are measured by the testing machine, followed by the proposal of mechanical model of the RSLD. Based on the experimental results, the mechanical model factors for each sub-component are determined by the data fitting method, which is then used to simulate the hysteresis loops of the damper. Meanwhile the experiment of the fabricated RSLD is carried out to study the influence of the loading rate and displacement amplitude on the mechanical properties. Finally, the response analysis of a six-story steel frame structure installed with different damper position configurations is performed, and the results reveal that the proposed RSLD has an outstanding re-centering capacity.

  3. Interpreting and managing blood lead levels of less than 10 microg/dL in children and reducing childhood exposure to lead: recommendations of the Centers for Disease Control and Prevention Advisory Committee on Childhood Lead Poisoning Prevention.

    PubMed

    Binns, Helen J; Campbell, Carla; Brown, Mary Jean

    2007-11-01

    Lead is a common environmental contaminant. Lead exposure is a preventable risk that exists in all areas of the United States. In children, lead is associated with impaired cognitive, motor, behavioral, and physical abilities. In 1991, the Centers for Disease Control and Prevention defined the blood lead level that should prompt public health actions as 10 microg/dL. Concurrently, the Centers for Disease Control and Prevention also recognized that a blood lead level of 10 microg/dL did not define a threshold for the harmful effects of lead. Research conducted since 1991 has strengthened the evidence that children's physical and mental development can be affected at blood lead levels of < 10 microg/dL. In this report we provide information to help clinicians understand blood lead levels < 10 microg/dL, identify gaps in knowledge concerning lead levels in this range, and outline strategies to reduce childhood exposures to lead. We also summarize scientific data relevant to counseling, blood lead screening, and lead-exposure risk assessment. To aid in the interpretation of blood lead levels, clinicians should understand the laboratory error range for blood lead values and, if possible, select a laboratory that achieves routine performance within +/-2 microg/dL. Clinicians should obtain an environmental history on all children they examine, provide families with lead-prevention counseling, and follow blood lead screening recommendations established for their areas. As circumstances permit, clinicians should consider referral to developmental programs for children at high risk for exposure to lead and more frequent rescreening of children with blood lead levels approaching 10 microg/dL. In addition, clinicians should direct parents to agencies and sources of information that will help them establish a lead-safe environment for their children. For these preventive strategies to succeed, partnerships between health care providers, families, and local public health and

  4. Direct Laser Acceleration in Laser Wakefield Accelerators

    NASA Astrophysics Data System (ADS)

    Shaw, J. L.; Froula, D. H.; Marsh, K. A.; Joshi, C.; Lemos, N.

    2017-10-01

    The direct laser acceleration (DLA) of electrons in a laser wakefield accelerator (LWFA) has been investigated. We show that when there is a significant overlap between the drive laser and the trapped electrons in a LWFA cavity, the accelerating electrons can gain energy from the DLA mechanism in addition to LWFA. The properties of the electron beams produced in a LWFA, where the electrons are injected by ionization injection, have been investigated using particle-in-cell (PIC) code simulations. Particle tracking was used to demonstrate the presence of DLA in LWFA. Further PIC simulations comparing LWFA with and without DLA show that the presence of DLA can lead to electron beams that have maximum energies that exceed the estimates given by the theory for the ideal blowout regime. The magnitude of the contribution of DLA to the energy gained by the electron was found to be on the order of the LWFA contribution. The presence of DLA in a LWFA can also lead to enhanced betatron oscillation amplitudes and increased divergence in the direction of the laser polarization. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  5. Iowa Acceleration Scale Manual: A Guide for Whole-Grade Acceleration K-8. (3rd Edition, Manual)

    ERIC Educational Resources Information Center

    Assouline, Susan G.; Colangelo, Nicholas; Lupkowski-Shoplik, Ann; Forstadt, Leslie; Lipscomb, Jonathon

    2009-01-01

    Feedback from years of nationwide use has resulted in a 3rd Edition of this unique, systematic, and objective guide to considering and implementing academic acceleration. Developed and tested by the Belin-Blank Center at the University of Iowa, the IAS ensures that acceleration decisions are systematic, thoughtful, well reasoned, and defensible.…

  6. Legacy lead arsenate soil contamination at childcare centers in the Yakima Valley, Central Washington, USA.

    PubMed

    Durkee, Jenna; Bartrem, Casey; Möller, Gregory

    2017-02-01

    From the early 1900s to the 1950s, Yakima Valley orchards were commonly treated with lead arsenate (LA) insecticides. Lead (Pb) and arsenic (As) soil contamination has been identified on former orchard lands throughout Central Washington and pose a threat to human health and the environment. The levels of Pb and As in soil and interior dust at participating childcare centers in the Upper Yakima Valley (Yakima County), Washington were sampled to explore exposure potential for young children. Childcare center soils were collected from two soil depths, homogenized, and analyzed in bulk by a field-portable X-ray fluorescence spectrometer (XRF). Interior dust wipes samples were collected from at least two locations in each facility. All soil samples >250 mg/kg Pb and/or >20 As mg/kg were sieved to 250 μm, tested by XRF a second time, and analyzed via acid digestion and inductively coupled plasma mass spectrometry (ICP-MS) analysis. Bulk and sieved XRF results, as well as ICP-MS to XRF results were strongly correlated. Maximum Pb and As XRF results indicated that 4 (21%) and 8 (42%) of the 19 childcare centers surveyed exceeded the regulatory standard for Pb and As, respectively. Historic land use was significantly associated with elevated Pb and As levels. Interior dust loadings were below United States Environmental Protection Agency (EPA) guidelines. Childcare centers are areas of intensive use for children and when coupled with potential residential exposure in their homes, the total daily exposure is a potential hazard to children. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Complementary and alternative medicine and supportive care at leading cancer centers: a systematic analysis of websites.

    PubMed

    Brauer, Jeremy A; El Sehamy, Adam; Metz, James M; Mao, Jun J

    2010-02-01

    With increasing frequency, patients with cancer and their family members are turning to the Internet to educate themselves about their disease and treatment options, including complementary and alternative medicine (CAM) and supportive care. However, very little is known about how national leading cancer centers represent these therapies via their websites. Simulating the perspective of an information-seeking patient or family member, we performed a systematic analysis of the websites of 41 National Cancer Institute designated comprehensive cancer centers. Two researchers independently evaluated websites, recorded CAM information, and rated quality of the websites using a 4-item Likert scale (overall, information, presentation, and navigation) with Cronbach's alpha = 0.97. Rating was adequately correlated between the two raters (correlation coefficient 0.8). Of 41 centers, 12 (29%) did not have functional websites with regard to information related to CAM. The most common CAM approaches mentioned were: acupuncture (59%), meditation/nutrition/spiritual support/yoga (56% for each), massage therapy (54%), and music therapy (51%). Twenty-three (23; 56%) presented information on support groups, 19 (46%) on patient seminars, 18 (44%) on survivorship effort, and 17 (41%) on symptom management clinics. Twenty-nine (29) (71%) of these websites had a telephone number available, 22 (54%) mentioned at least one ongoing research opportunity, and 19 (46%) provided links to the National Center for Complementary and Alternative Medicine website. Median rating of the quality of websites was 50 of 100, with only 7 (17%) of centers receiving a composite score 80 (excellent) or better. While a growing number of leading cancer centers provide information about CAM and supportive oncology information for patients via their websites, the quality and ease of navigation of these sites remain highly variable. Effective development and redesign of many of the websites is needed to better

  8. Should the Centers for Disease Control and Prevention’s Childhood Lead Poisoning Intervention Level Be Lowered?

    PubMed Central

    Bernard, Susan M.

    2003-01-01

    The US Centers for Disease Control and Prevention (CDC) in 1991 chose 10 μg/dL as an initial screening level for lead in children’s blood. Current data on health risks and intervention options do not support generally lowering that level, but federal lead poisoning prevention efforts can be improved by revising the follow-up testing schedule for infants aged 1 year or less with blood lead levels of 5 μg/dL or higher; universal education about lead exposure risks; universal administration of improved, locally validated risk-screening questionnaires; enhanced compliance with targeted screening recommendations and federal health program requirements; and development by regulatory agencies of primary prevention criteria that do not use the CDC’s intervention level as a target “safe” lead exposure. PMID:12893607

  9. Readability of Spine-Related Patient Education Materials From Leading Orthopedic Academic Centers.

    PubMed

    Ryu, Justine H; Yi, Paul H

    2016-05-01

    Cross-sectional analysis of online spine-related patient education materials from leading academic centers. To assess the readability levels of spine surgery-related patient education materials available on the websites of academic orthopedic surgery departments. The Internet is becoming an increasingly popular resource for patient education. Yet many previous studies have found that Internet-based orthopedic-related patient education materials from subspecialty societies are written at a level too difficult for the average American; however, no prior study has assessed the readability of spine surgery-related patient educational materials from leading academic centers. All spine surgery-related articles from the online patient education libraries of the top five US News & World Report-ranked orthopedic institutions were assessed for readability using the Flesch-Kincaid (FK) readability test. Mean readability levels of articles amongst the five academic institutions and articles were compared. We also determined the number of articles with readability levels at or below the recommended sixth- or eight-grade levels. Intraobserver and interobserver reliability of readability assessment were assessed. A total of 122 articles were reviewed. The mean overall FK grade level was 11.4; the difference in mean FK grade level between each department varied significantly (range, 9.3-13.4; P < 0.0001). Twenty-three articles (18.9%) had a readability level at or below the eighth grade level, and only one (0.8%) was at or below the sixth grade level. Intraobserver and interobserver reliability were both excellent (intraclass correlation coefficient of 1 for both). Online patient education materials related to spine from academic orthopedic centers are written at a level too high for the average patient, consistent with spine surgery-related patient education materials provided by the American Academy of Orthopaedic Surgeons and spine subspecialty societies. This study

  10. Development of Acceleration Sensor and Acceleration Evaluation System for Super-Low-Range Frequencies

    NASA Astrophysics Data System (ADS)

    Asano, Shogo; Matsumoto, Hideki

    2001-05-01

    This paper describes the development process for acceleration sensors used on automobiles and an acceleration evaluation system designed specifically for acceleration at super-low-range frequencies. The features of the newly developed sensor are as follows. 1) Original piezo-bimorph design based on a disc-center-fixed structure achieves pyroeffect cancelling and stabilization of sensor characteristics and enables the detection of the acceleration of 0.0009 G at the super-low-range-frequency of 0.03 Hz. 2) The addition of a self-diagnostic function utilizing the characteristics of piezoceramics enables constant monitoring of sensor failure. The frequency range of acceleration for accurate vehicle motion control is considered to be from DC to about 50 Hz. However, the measurement of acceleration in the super-low-range frequency near DC has been difficult because of mechanical and electrical noise interruption. This has delayed the development of the acceleration sensor for automotive use. We have succeeded in the development of an acceleration evaluation system for super-low-range frequencies from 0.015 Hz to 2 Hz with detection of the acceleration range from 0.0002 G (0.2 gal) to 1 G, as well as the development of a piezoelectric-type acceleration sensor for automotive use.

  11. Giga-electronvolt electrons due to a transition from laser wakefield acceleration to plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Masson-Laborde, P. E.; Mo, M. Z.; Ali, A.; Fourmaux, S.; Lassonde, P.; Kieffer, J. C.; Rozmus, W.; Teychenné, D.; Fedosejevs, R.

    2014-12-01

    We show through experiments that a transition from laser wakefield acceleration (LWFA) regime to a plasma wakefield acceleration (PWFA) regime can drive electrons up to energies close to the GeV level. Initially, the acceleration mechanism is dominated by the bubble created by the laser in the nonlinear regime of LWFA, leading to an injection of a large number of electrons. After propagation beyond the depletion length, leading to a depletion of the laser pulse, whose transverse ponderomotive force is not able to sustain the bubble anymore, the high energy dense bunch of electrons propagating inside bubble will drive its own wakefield by a PWFA regime. This wakefield will be able to trap and accelerate a population of electrons up to the GeV level during this second stage. Three dimensional particle-in-cell simulations support this analysis and confirm the scenario.

  12. Space Acceleration Measurement System (SAMS)/Orbital Acceleration Research Experiment (OARE)

    NASA Technical Reports Server (NTRS)

    Hakimzadeh, Roshanak

    1998-01-01

    The Life and Microgravity Spacelab (LMS) payload flew on the Orbiter Columbia on mission STS-78 from June 20th to July 7th, 1996. The LMS payload on STS-78 was dedicated to life sciences and microgravity experiments. Two accelerometer systems managed by the NASA Lewis Research Center (LERC) flew to support these experiments, namely the Orbital Acceleration Research Experiment (OARE) and the Space Acceleration Measurements System (SAMS). In addition, the Microgravity Measurement Assembly (NOAA), managed by the European Space Research and Technology Center (ESA/ESTEC), and sponsored by NASA, collected acceleration data in support of the experiments on-board the LMS mission. OARE downlinked real-time quasi-steady acceleration data, which was provided to the investigators. The SAMS recorded higher frequency data on-board for post-mission analysis. The MMA downlinked real-time quasi-steady as well as higher frequency acceleration data, which was provided to the investigators. The Principal Investigator Microgravity Services (PIMS) project at NASA LERC supports principal investigators of microgravity experiments as they evaluate the effects of varying acceleration levels on their experiments. A summary report was prepared by PIMS to furnish interested experiment investigators with a guide to evaluate the acceleration environment during STS-78, and as a means of identifying areas which require further study. The summary report provides an overview of the STS-78 mission, describes the accelerometer systems flown on this mission, discusses some specific analyses of the accelerometer data in relation to the various activities which occurred during the mission, and presents plots resulting from these analyses as a snapshot of the environment during the mission. Numerous activities occurred during the STS-78 mission that are of interest to the low-gravity community. Specific activities of interest during this mission were crew exercise, radiator deployment, Vernier Reaction

  13. EDITORIAL: Laser and plasma accelerators Laser and plasma accelerators

    NASA Astrophysics Data System (ADS)

    Bingham, Robert

    2009-02-01

    by Chen et al where the driver, instead of being a laser, is a whistler wave known as the magnetowave plasma accelerator. The application to electron--positron plasmas that are found around pulsars is studied in the paper by Shukla, and to muon acceleration by Peano et al. Electron wakefield experiments are now concentrating on control and optimisation of high-quality beams that can be used as drivers for novel radiation sources. Studies by Thomas et al show that filamentation has a deleterious effect on the production of high quality mono-energetic electron beams and is caused by non-optimal choice of focusing geometry and/or electron density. It is crucial to match the focusing with the right plasma parameters and new types of plasma channels are being developed, such as the magnetically controlled plasma waveguide reported by Froula et al. The magnetic field provides a pressure profile shaping the channel to match the guiding conditions of the incident laser, resulting in predicted electron energies of 3GeV. In the forced laser-wakefield experiment Fang et al show that pump depletion reduces or inhibits the acceleration of electrons. One of the earlier laser acceleration concepts known as the beat wave may be revived due to the work by Kalmykov et al who report on all-optical control of nonlinear focusing of laser beams, allowing for stable propagation over several Rayleigh lengths with pre-injected electrons accelerated beyond 100 MeV. With the increasing number of petawatt lasers, attention is being focused on different acceleration regimes such as stochastic acceleration by counterpropagating laser pulses, the relativistic mirror, or the snow-plough effect leading to single-step acceleration reported by Mendonca. During wakefield acceleration the leading edge of the pulse undergoes frequency downshifting and head erosion as the laser energy is transferred to the wake while the trailing edge of the laser pulse undergoes frequency up-shift. This is commonly known

  14. National Institute of Nursing Research Centers of Excellence: a logic model for sustainability, leveraging resources, and collaboration to accelerate cross-disciplinary science.

    PubMed

    Dorsey, Susan G; Schiffman, Rachel; Redeker, Nancy S; Heitkemper, Margaret; McCloskey, Donna Jo; Weglicki, Linda S; Grady, Patricia A

    2014-01-01

    The National Institute of Nursing Research (NINR) Centers of Excellence program is a catalyst enabling institutions to develop infrastructure and administrative support for creating cross-disciplinary teams that bring multiple strategies and expertise to bear on common areas of science. Centers are increasingly collaborative with campus partners and reflect an integrated team approach to advance science and promote the development of scientists in these areas. The purpose of this paper is to present the NINR Logic Model for Center Sustainability. The components of the logic model were derived from the presentations and robust discussions at the 2013 NINR center directors' meeting focused on best practices for leveraging resources and collaboration as methods to promote center sustainability. Collaboration through development and implementation of cross-disciplinary research teams is critical to accelerate the generation of new knowledge for solving fundamental health problems. Sustainability of centers as a long-term outcome beyond the initial funding can be enhanced by thoughtful planning of inputs, activities, and leveraging resources across multiple levels. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Development and Implementation of NASA's Lead Center for Rocket Propulsion Testing

    NASA Technical Reports Server (NTRS)

    Dawson, Michael C.

    2001-01-01

    With the new millennium, NASA's John C. Stennis Space Center (SSC) continues to develop and refine its role as rocket test service provider for NASA and the Nation. As Lead Center for Rocket Propulsion Testing (LCRPT), significant progress has been made under SSC's leadership to consolidate and streamline NASA's rocket test infrastructure and make this vital capability truly world class. NASA's Rocket Propulsion Test (RPT) capability consists of 32 test positions with a replacement value in excess of $2B. It is dispersed at Marshall Space Flight Center (MSFC), Johnson Space Center (JSC)-White Sands Test Facility (WSTF), Glenn Research Center (GRC)-Plum Brook (PB), and SSC and is sized appropriately to minimize duplication and infrastructure costs. The LCRPT also provides a single integrated point of entry into NASA's rocket test services. The RPT capability is managed through the Rocket Propulsion Test Management Board (RPTMB), chaired by SSC with representatives from each center identified above. The Board is highly active, meeting weekly, and is key to providing responsive test services for ongoing operational and developmental NASA and commercial programs including Shuttle, Evolved Expendable Launch Vehicle, and 2nd and 3rd Generation Reusable Launch Vehicles. The relationship between SSC, the test provider, and the hardware developers, like MSFC, is critical to the implementation of the LCRPT. Much effort has been expended to develop and refine these relationships with SSC customers. These efforts have met with success and will continue to be a high priority to SSC for the future. To data in the exercise of its role, the LCRPT has made 22 test assignments and saved or avoided approximately $51M. The LCRPT directly manages approximately $30M annually in test infrastructure costs including facility maintenance and upgrades, direct test support, and test technology development. This annual budges supports rocket propulsion test programs which have an annual budget

  16. Absolute acceleration measurements on STS-50 from the Orbital Acceleration Research Experiment (OARE)

    NASA Technical Reports Server (NTRS)

    Blanchard, Robert C.; Nicholson, John Y.; Ritter, James R.

    1994-01-01

    Orbital Acceleration Research Experiment (OARE) data on Space Transportation System (STS)-50 have been examined in detail during a 2-day time period. Absolute acceleration levels have been derived at the OARE location, the orbiter center-of-gravity, and at the STS-50 spacelab Crystal Growth Facility. During the interval, the tri-axial OARE raw telemetered acceleration measurements have been filtered using a sliding trimmed mean filter in order to remove large acceleration spikes (e.g., thrusters) and reduce the noise. Twelve OARE measured biases in each acceleration channel during the 2-day interval have been analyzed and applied to the filtered data. Similarly, the in situ measured x-axis scale factors in the sensor's most sensitive range were also analyzed and applied to the data. Due to equipment problem(s) on this flight, both y- and z-axis sensitive range scale factors were determined in a separate process using orbiter maneuvers and subsequently applied to the data. All known significant low-frequency corrections at the OARE location (i.e., both vertical and horizontal gravity-gradient, and rotational effects) were removed from the filtered data in order to produce the acceleration components at the orbiter center-of-gravity, which are the aerodynamic signals along each body axis. Results indicate that there is a force being applied to the Orbiter in addition to the aerodynamic forces. The OARE instrument and all known gravitational and electromagnetic forces have been reexamined, but none produces the observed effect. Thus, it is tentatively concluded that the orbiter is creating the environment observed. At least part of this force is thought to be due to the Flash Evaporator System.

  17. Two-stage acceleration of protons from relativistic laser-solid interaction

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

    Liu Jinlu; Sheng, Z. M.; Zheng, J.

    2012-12-21

    A two-stage proton acceleration scheme using present-day intense lasers and a unique target design is proposed. The target system consists of a hollow cylinder, inside which is a hollow cone, which is followed by the main target with a flat front and dish-like flared rear surface. At the center of the latter is a tapered proton layer, which is surrounded by outer proton layers at an angle to it. In the first acceleration stage, protons in both layers are accelerated by target normal sheath acceleration. The center-layer protons are accelerated forward along the axis and the side protons are acceleratedmore » and focused towards them. As a result, the side-layer protons radially compress as well as axially further accelerate the front part of the accelerating center-layer protons in the second stage, which are also radially confined and guided by the field of the fast electrons surrounding them. Two-dimensional particle-incell simulation shows that a 79fs 8.5 Multiplication-Sign 10{sup 20} W/cm{sup 2} laser pulse can produce a proton bunch with {approx} 267MeV maximum energy and {approx} 9.5% energy spread, which may find many applications, including cancer therapy.« less

  18. Proceedings of the 1995 Particle Accelerator Conference and international Conference on High-Energy Accelerators

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

    None

    1996-01-01

    Papers from the sixteenth biennial Particle Accelerator Conference, an international forum on accelerator science and technology held May 1–5, 1995, in Dallas, Texas, organized by Los Alamos National Laboratory (LANL) and Stanford Linear Accelerator Center (SLAC), jointly sponsored by the Institute of Electrical and Electronics Engineers (IEEE) Nuclear and Plasma Sciences Society (NPSS), the American Physical Society (APS) Division of Particles and Beams (DPB), and the International Union of Pure and Applied Physics (IUPAP), and conducted with support from the US Department of Energy, the National Science Foundation, and the Office of Naval Research.

  19. F-centers mechanism of long-term relaxation in lead zirconate-titanate based piezoelectric ceramics. 2. After-field relaxation

    NASA Astrophysics Data System (ADS)

    Ishchuk, V. M.; Kuzenko, D. V.

    2016-08-01

    The paper presents results of experimental study of the dielectric constant relaxation during aging process in Pb(Zr,Ti)O3 based solid solutions (PZT) after action of external DC electric field. The said process is a long-term one and is described by the logarithmic function of time. Reversible and nonreversible relaxation process takes place depending on the field intensity. The relaxation rate depends on the field strength also, and the said dependence has nonlinear and nonmonotonic form, if external field leads to domain disordering. The oxygen vacancies-based model for description of the long-term relaxation processes is suggested. The model takes into account the oxygen vacancies on the sample's surface ends, their conversion into F+- and F0-centers under external effects and subsequent relaxation of these centers into the simple oxygen vacancies after the action termination. F-centers formation leads to the violation of the original sample's electroneutrality, and generate intrinsic DC electric field into the sample. Relaxation of F-centers is accompanied by the reduction of the electric field, induced by them, and relaxation of the dielectric constant, as consequent effect.

  20. Giga-electronvolt electrons due to a transition from laser wakefield acceleration to plasma wakefield acceleration

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

    Masson-Laborde, P. E., E-mail: paul-edouard.masson-laborde@cea.fr; Teychenné, D.; Mo, M. Z.

    2014-12-15

    We show through experiments that a transition from laser wakefield acceleration (LWFA) regime to a plasma wakefield acceleration (PWFA) regime can drive electrons up to energies close to the GeV level. Initially, the acceleration mechanism is dominated by the bubble created by the laser in the nonlinear regime of LWFA, leading to an injection of a large number of electrons. After propagation beyond the depletion length, leading to a depletion of the laser pulse, whose transverse ponderomotive force is not able to sustain the bubble anymore, the high energy dense bunch of electrons propagating inside bubble will drive its ownmore » wakefield by a PWFA regime. This wakefield will be able to trap and accelerate a population of electrons up to the GeV level during this second stage. Three dimensional particle-in-cell simulations support this analysis and confirm the scenario.« less

  1. The Chaplygin Sleigh with Parametric Excitation: Chaotic Dynamics and Nonholonomic Acceleration

    NASA Astrophysics Data System (ADS)

    Bizyaev, Ivan A.; Borisov, Alexey V.; Mamaev, Ivan S.

    2017-12-01

    This paper is concerned with the Chaplygin sleigh with time-varying mass distribution (parametric excitation). The focus is on the case where excitation is induced by a material point that executes periodic oscillations in a direction transverse to the plane of the knife edge of the sleigh. In this case, the problem reduces to investigating a reduced system of two first-order equations with periodic coefficients, which is similar to various nonlinear parametric oscillators. Depending on the parameters in the reduced system, one can observe different types of motion, including those accompanied by strange attractors leading to a chaotic (diffusion) trajectory of the sleigh on the plane. The problem of unbounded acceleration (an analog of Fermi acceleration) of the sleigh is examined in detail. It is shown that such an acceleration arises due to the position of the moving point relative to the line of action of the nonholonomic constraint and the center of mass of the platform. Various special cases of existence of tensor invariants are found.

  2. Theory of unfolded cyclotron accelerator

    NASA Astrophysics Data System (ADS)

    Rax, J.-M.; Robiche, J.

    2010-10-01

    An acceleration process based on the interaction between an ion, a tapered periodic magnetic structure, and a circularly polarized oscillating electric field is identified and analyzed, and its potential is evaluated. A Hamiltonian analysis is developed in order to describe the interplay between the cyclotron motion, the electric acceleration, and the magnetic modulation. The parameters of this universal class of magnetic modulation leading to continuous acceleration without Larmor radius increase are expressed analytically. Thus, this study provides the basic scaling of what appears as a compact unfolded cyclotron accelerator.

  3. Clinical outcomes and cost effectiveness of accelerated diagnostic protocol in a chest pain center compared with routine care of patients with chest pain.

    PubMed

    Asher, Elad; Reuveni, Haim; Shlomo, Nir; Gerber, Yariv; Beigel, Roy; Narodetski, Michael; Eldar, Michael; Or, Jacob; Hod, Hanoch; Shamiss, Arie; Matetzky, Shlomi

    2015-01-01

    The aim of this study was to compare in patients presenting with acute chest pain the clinical outcomes and cost-effectiveness of an accelerated diagnostic protocol utilizing contemporary technology in a chest pain unit versus routine care in an internal medicine department. Hospital and 90-day course were prospectively studied in 585 consecutive low-moderate risk acute chest pain patients, of whom 304 were investigated in a designated chest pain center using a pre-specified accelerated diagnostic protocol, while 281 underwent routine care in an internal medicine ward. Hospitalization was longer in the routine care compared with the accelerated diagnostic protocol group (p<0.001). During hospitalization, 298 accelerated diagnostic protocol patients (98%) vs. 57 (20%) routine care patients underwent non-invasive testing, (p<0.001). Throughout the 90-day follow-up, diagnostic imaging testing was performed in 125 (44%) and 26 (9%) patients in the routine care and accelerated diagnostic protocol patients, respectively (p<0.001). Ultimately, most patients in both groups had non-invasive imaging testing. Accelerated diagnostic protocol patients compared with those receiving routine care was associated with a lower incidence of readmissions for chest pain [8 (3%) vs. 24 (9%), p<0.01], and acute coronary syndromes [1 (0.3%) vs. 9 (3.2%), p<0.01], during the follow-up period. The accelerated diagnostic protocol remained a predictor of lower acute coronary syndromes and readmissions after propensity score analysis [OR = 0.28 (CI 95% 0.14-0.59)]. Cost per patient was similar in both groups [($2510 vs. $2703 for the accelerated diagnostic protocol and routine care group, respectively, (p = 0.9)]. An accelerated diagnostic protocol is clinically superior and as cost effective as routine in acute chest pain patients, and may save time and resources.

  4. Clinical Outcomes and Cost Effectiveness of Accelerated Diagnostic Protocol in a Chest Pain Center Compared with Routine Care of Patients with Chest Pain

    PubMed Central

    Asher, Elad; Reuveni, Haim; Shlomo, Nir; Gerber, Yariv; Beigel, Roy; Narodetski, Michael; Eldar, Michael; Or, Jacob; Hod, Hanoch; Shamiss, Arie; Matetzky, Shlomi

    2015-01-01

    Aims The aim of this study was to compare in patients presenting with acute chest pain the clinical outcomes and cost-effectiveness of an accelerated diagnostic protocol utilizing contemporary technology in a chest pain unit versus routine care in an internal medicine department. Methods and Results Hospital and 90-day course were prospectively studied in 585 consecutive low-moderate risk acute chest pain patients, of whom 304 were investigated in a designated chest pain center using a pre-specified accelerated diagnostic protocol, while 281 underwent routine care in an internal medicine ward. Hospitalization was longer in the routine care compared with the accelerated diagnostic protocol group (p<0.001). During hospitalization, 298 accelerated diagnostic protocol patients (98%) vs. 57 (20%) routine care patients underwent non-invasive testing, (p<0.001). Throughout the 90-day follow-up, diagnostic imaging testing was performed in 125 (44%) and 26 (9%) patients in the routine care and accelerated diagnostic protocol patients, respectively (p<0.001). Ultimately, most patients in both groups had non-invasive imaging testing. Accelerated diagnostic protocol patients compared with those receiving routine care was associated with a lower incidence of readmissions for chest pain [8 (3%) vs. 24 (9%), p<0.01], and acute coronary syndromes [1 (0.3%) vs. 9 (3.2%), p<0.01], during the follow-up period. The accelerated diagnostic protocol remained a predictor of lower acute coronary syndromes and readmissions after propensity score analysis [OR = 0.28 (CI 95% 0.14–0.59)]. Cost per patient was similar in both groups [($2510 vs. $2703 for the accelerated diagnostic protocol and routine care group, respectively, (p = 0.9)]. Conclusion An accelerated diagnostic protocol is clinically superior and as cost effective as routine in acute chest pain patients, and may save time and resources. PMID:25622029

  5. Accelerated Districts--The Next Step. A Summary of Research and Design.

    ERIC Educational Resources Information Center

    Driver, Cyrus; And Others

    The National Center for the Accelerated Schools Project at Stanford University has recognized that district-level change is necessary if changes at accelerated schools are to gain permanence and become widespread. The Center has therefore initiated a research and development project to design a set of models on which districts can reconstitute…

  6. Impact of accelerated progression to AIDS on public health monitoring of late HIV diagnosis.

    PubMed

    Sabharwal, Charulata J; Sepkowitz, Kent; Mehta, Reshma; Shepard, Colin; Bodach, Sara; Torian, Lucia; Begier, Elizabeth M

    2011-03-01

    Some patients develop AIDS within a year of HIV infection ("accelerated progression"). Classifying such cases as late HIV diagnosis may lead to inaccurate evaluation of HIV testing efforts. We sought to determine this group's contribution to overall late diagnosis rates. To identify cases of accelerated progression (development of AIDS within 12 months of a negative HIV test), we reviewed published HIV seroconverter cohort studies and used New York City's (NYC) HIV/AIDS surveillance registry. From the literature review, three seroconverter cohort studies revealed that 1.0-3.6% of participants had accelerated progression to AIDS. Applying this frequency estimate to the number of new infections in NYC (4762) for 2006 calculated by the Centers for Diseases Control and Prevention's incidence formula, we estimated that 3.6-13.0% of 1317 NYC HIV cases who are diagnosed with AIDS within 12 months of HIV diagnosis are accelerated progressors, not persons HIV infected for many years who did not test and present with AIDS (i.e., delayed diagnosis). In addition, our analysis of the 2006 NYC surveillance registry confirmed the occurrence of accelerated progression in a population-based setting; 67 accelerated progressors were reported and 9 (13%) could be confirmed through follow-up medical record review. With increased HIV testing initiatives, the irreducible proportion of AIDS cases with accelerated progression must be considered when interpreting late diagnosis data.

  7. Muscle Forces and Their Contributions to Vertical and Horizontal Acceleration of the Center of Mass During Sit-to-Stand Transfer in Young, Healthy Adults.

    PubMed

    Caruthers, Elena J; Thompson, Julie A; Chaudhari, Ajit M W; Schmitt, Laura C; Best, Thomas M; Saul, Katherine R; Siston, Robert A

    2016-10-01

    Sit-to-stand transfer is a common task that is challenging for older adults and others with musculoskeletal impairments. Associated joint torques and muscle activations have been analyzed two-dimensionally, neglecting possible three-dimensional (3D) compensatory movements in those who struggle with sit-to-stand transfer. Furthermore, how muscles accelerate an individual up and off the chair remains unclear; such knowledge could inform rehabilitation strategies. We examined muscle forces, muscleinduced accelerations, and interlimb muscle force differences during sit-to-stand transfer in young, healthy adults. Dynamic simulations were created using a custom 3D musculoskeletal model; static optimization and induced acceleration analysis were used to determine muscle forces and their induced accelerations, respectively. The gluteus maximus generated the largest force (2009.07 ± 277.31 N) and was a main contributor to forward acceleration of the center of mass (COM) (0.62 ± 0.18 m/s(2)), while the quadriceps opposed it. The soleus was a main contributor to upward (2.56 ± 0.74 m/s(2)) and forward acceleration of the COM (0.62 ± 0.33 m/s(2)). Interlimb muscle force differences were observed, demonstrating lower limb symmetry cannot be assumed during this task, even in healthy adults. These findings establish a baseline from which deficits and compensatory strategies in relevant populations (eg, elderly, osteoarthritis) can be identified.

  8. Joint Center for Artificial Photosynthesis (JCAP): DOE's Solar Fuels Energy Innovation Hub (2011 EFRC Summit)

    ScienceCinema

    Lewis, Nate

    2018-02-16

    The Joint Center for Artificial Photosynthesis (JCAP) is a DOE Energy Innovation Hub focused on fuels from sunlight. JCAP's Director, Nate Lewis, spoke at the 2011 EFRC Summit about what JCAP is and how it is partnering with the EFRC community to accelerate the progress towards new solar fuels. The 2011 EFRC Summit and Forum brought together the EFRC community and science and policy leaders from universities, national laboratories, industry and government to discuss "Science for our Nation's Energy Future." In August 2009, the Office of Science established 46 Energy Frontier Research Centers. The EFRCs are collaborative research efforts intended to accelerate high-risk, high-reward fundamental research, the scientific basis for transformative energy technologies of the future. These Centers involve universities, national laboratories, nonprofit organizations, and for-profit firms, singly or in partnerships, selected by scientific peer review. They are funded at $2 to $5 million per year for a total planned DOE commitment of $777 million over the initial five-year award period, pending Congressional appropriations. These integrated, multi-investigator Centers are conducting fundamental research focusing on one or more of several “grand challenges” and use-inspired “basic research needs” recently identified in major strategic planning efforts by the scientific community. The purpose of the EFRCs is to integrate the talents and expertise of leading scientists in a setting designed to accelerate research that transforms the future of energy and the environment.

  9. Production and isolation of homologs of flerovium and element 115 at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry

    DOE PAGES

    Despotopulos, John D.; Kmak, Kelly N.; Gharibyan, Narek; ...

    2015-10-01

    Here, new procedures have been developed to isolate no-carrier-added (NCA) radionuclides of the homologs and pseudo-homologs of flerovium (Hg, Sn) and element 115 (Sb), produced by 12–15 MeV proton irradiation of foil stacks with the tandem Van-de-Graaff accelerator at the Lawrence Livermore National Laboratory Center for Accelerator Mass Spectrometry (CAMS) facility. The separation of 113Sn from natIn foil was performed with anion-exchange chromatography from hydrochloric and nitric acid matrices. A cation-exchange chromatography method based on hydrochloric and mixed hydrochloric/hydroiodic acids was used to separate 124Sb from natSn foil. A procedure using Eichrom TEVA resin was developed to separate 197Hg frommore » Au foil. These results demonstrate the suitability of using the CAMS facility to produce NCA radioisotopes for studies of transactinide homologs.« less

  10. Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments

    USGS Publications Warehouse

    Chang, Jefferson C.; Lockner, David A.; Reches, Z.

    2012-01-01

    After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.

  11. Regeneration of Airy pulses in fiber-optic links with dispersion management of the two leading dispersion terms of opposite signs

    NASA Astrophysics Data System (ADS)

    Driben, R.; Meier, T.

    2014-04-01

    Dispersion management of periodically alternating fiber sections with opposite signs of two leading dispersion terms is applied for the regeneration of self-accelerating truncated Airy pulses. It is demonstrated that for such a dispersion management scheme, the direction of the acceleration of the pulse is reversed twice within each period. In this scheme the system features light hot spots in the center of each fiber section, where the energy of the light pulse is tightly focused in a short temporal slot. Comprehensive numerical studies demonstrate a long-lasting propagation also under the influence of a strong fiber Kerr nonlinearity.

  12. Rail accelerators for space transportation: An experimental investigation

    NASA Technical Reports Server (NTRS)

    Zana, L. M.; Kerslake, W. R.; Sturman, J. L.

    1986-01-01

    An experimental program was conducted at the Lewis Research Center with the objective of investigating the technical feasibility of rail accelerators for propulsion applications. Single-stage, plasma driven rail accelerators of small (4 by 6 mm) and medium (12.5 by 12.5 mm) bores were tested at peak accelerating currents of 50 to 450 kA. Streak-camera photography was used to provide a qualitative description of plasma armature acceleration. The effects of plasma blowby and varying bore pressure on the behavior of plasma armatures were studied.

  13. Angular distribution of electrons from powerful accelerators

    NASA Astrophysics Data System (ADS)

    Stepovik, A. P.; Lartsev, V. D.; Blinov, V. S.

    2007-07-01

    A technique for measuring the angular distribution of electrons escaping from the center of the window of the IGUR-3 and ÉMIR-M powerful accelerators (designed at the All-Russia Institute of Technical Physics, Russian Federal Nuclear Center) into ambient air is presented, and measurement data are reported. The number of electrons is measured with cable detectors (the solid angle of the collimator of the detector is ≈0.01 sr). The measurements are made in three azimuthal directions in 120° intervals in the polar angle range 0 22°. The angular distributions of the electrons coming out of the accelerators are represented in the form of B splines.

  14. Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

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

    Spentzouris, P.; /Fermilab; Cary, J.

    PASS organization for software development and applications accounts for the natural domain areas (beam dynamics, electromagnetics, and advanced acceleration), and all areas depend on the enabling technologies activities, such as solvers and component technology, to deliver the desired performance and integrated simulation environment. The ComPASS applications focus on computationally challenging problems important for design or performance optimization to all major HEP, NP, and BES accelerator facilities. With the cost and complexity of particle accelerators rising, the use of computation to optimize their designs and find improved operating regimes becomes essential, potentially leading to significant cost savings with modest investment.« less

  15. Applications of the Strategic Defense Initiative's compact accelerators

    NASA Technical Reports Server (NTRS)

    Montanarelli, Nick; Lynch, Ted

    1991-01-01

    The Strategic Defense Initiative's (SDI) investment in particle accelerator technology for its directed energy weapons program has produced breakthroughs in the size and power of new accelerators. These accelerators, in turn, have produced spinoffs in several areas: the radio frequency quadrupole linear accelerator (RFQ linac) was recently incorporated into the design of a cancer therapy unit at the Loma Linda University Medical Center, an SDI-sponsored compact induction linear accelerator may replace Cobalt-60 radiation and hazardous ethylene-oxide as a method for sterilizing medical products, and other SDIO-funded accelerators may be used to produce the radioactive isotopes oxygen-15, nitrogen-13, carbon-11, and fluorine-18 for positron emission tomography (PET). Other applications of these accelerators include bomb detection, non-destructive inspection, decomposing toxic substances in contaminated ground water, and eliminating nuclear waste.

  16. Kazmerski Leads National Center for Solar Research

    Science.gov Websites

    center is a collaborative co-equal effort involving Sandia National Laboratories and NREL and helps the technologies and continue its leadership in the global marketplace." Kazmerski was NREL's first employee

  17. Systems and methods for cylindrical hall thrusters with independently controllable ionization and acceleration stages

    DOEpatents

    Diamant, Kevin David; Raitses, Yevgeny; Fisch, Nathaniel Joseph

    2014-05-13

    Systems and methods may be provided for cylindrical Hall thrusters with independently controllable ionization and acceleration stages. The systems and methods may include a cylindrical channel having a center axial direction, a gas inlet for directing ionizable gas to an ionization section of the cylindrical channel, an ionization device that ionizes at least a portion of the ionizable gas within the ionization section to generate ionized gas, and an acceleration device distinct from the ionization device. The acceleration device may provide an axial electric field for an acceleration section of the cylindrical channel to accelerate the ionized gas through the acceleration section, where the axial electric field has an axial direction in relation to the center axial direction. The ionization section and the acceleration section of the cylindrical channel may be substantially non-overlapping.

  18. Rail accelerator technology and applications

    NASA Technical Reports Server (NTRS)

    Zana, L. M.; Kerslake, W. R.

    1985-01-01

    Rail accelerators offer a viable means of launching ton-size payloads from the Earth's surface to space. The results of two mission studies which indicate that an Earth-to-Space Rail Launcher (ESRL) system is not only technically feasible but also economically beneficial, particularly when large amounts of bulk cago are to be delivered to space are given. An in-house experimental program at the Lewis Research Center (LeRC) was conducted in parallel with the mission studies with the objective of examining technical feasibility issues. A 1 m long - 12.5 by 12.5 mm bore rail accelerator as designed with clear polycarbonate sidewalls to visually observe the plasma armature acceleration. The general character of plasma/projectile dynamics is described for a typical test firing.

  19. Future HEP Accelerators: The US Perspective

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

    Bhat, Pushpalatha; Shiltsev, Vladimir

    2015-11-02

    Accelerator technology has advanced tremendously since the introduction of accelerators in the 1930s, and particle accelerators have become indispensable instruments in high energy physics (HEP) research to probe Nature at smaller and smaller distances. At present, accelerator facilities can be classified into Energy Frontier colliders that enable direct discoveries and studies of high mass scale particles and Intensity Frontier accelerators for exploration of extremely rare processes, usually at relatively low energies. The near term strategies of the global energy frontier particle physics community are centered on fully exploiting the physics potential of the Large Hadron Collider (LHC) at CERN throughmore » its high-luminosity upgrade (HL-LHC), while the intensity frontier HEP research is focused on studies of neutrinos at the MW-scale beam power accelerator facilities, such as Fermilab Main Injector with the planned PIP-II SRF linac project. A number of next generation accelerator facilities have been proposed and are currently under consideration for the medium- and long-term future programs of accelerator-based HEP research. In this paper, we briefly review the post-LHC energy frontier options, both for lepton and hadron colliders in various regions of the world, as well as possible future intensity frontier accelerator facilities.« less

  20. The international translational regenerative medicine center.

    PubMed

    Alexis, Mardi de Veuve; Grinnemo, Karl-Henrik; Jove, Richard

    2012-11-01

    The International Translational Regenerative Medicine Center, an organizing sponsor of the World Stem Cell Summit 2012, is a global initiative established in 2011 by founding partners Karolinska Institutet (Stockholm, Sweden) and Beckman Research Institute at City of Hope (CA, USA) with a mission to facilitate the acceleration of translational research and medicine on a global scale. Karolinska Institutet, home of the Nobel Prize in Medicine or Physiology, is one of the most prestigious medical research institutions in the world. The Beckman Research Institute/City of Hope is ranked among the leading NIH-designated comprehensive cancer research and treatment institutions in the USA, has the largest academic GMP facility and advanced drug discovery capability, and is a pioneer in diabetes research and treatment.

  1. Does technology acceleration equate to mask cost acceleration?

    NASA Astrophysics Data System (ADS)

    Trybula, Walter J.; Grenon, Brian J.

    2003-06-01

    The technology acceleration of the ITRS Roadmap has many implications on both the semiconductor sup-plier community and the manufacturers. INTERNATIONAL SEMATECH has revaluated the projected cost of advanced technology masks. Building on the methodology developed in 1996 for mask costs, this work provided a critical review of mask yields and factors relating to the manufacture of photolithography masks. The impact of the yields provided insight into the learning curve for leading edge mask manufac-turing. The projected mask set cost was surprising, and the ability to provide first and second year cost estimates provided additional information on technology introduction. From this information, the impact of technology acceleration can be added to the projected yields to evaluate the impact on mask costs.

  2. Post-accelerator issues at the IsoSpin Laboratory

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

    Chattopadhyay, S.; Nitschke, J.M.

    1994-05-01

    The workshop on ``Post-Accelerator Issues at the Isospin Laboratory`` was held at the Lawrence Berkeley Laboratory from October 27--29, 1993. It was sponsored by the Center for Beam Physics in the Accelerator and Fusion Research Division and the ISL Studies Group in the Nuclear Science Division. About forty scientists from around the world participated vigorously in this two and a half day workshop, (c.f. Agenda, Appendix D). Following various invited review talks from leading practitioners in the field on the first day, the workshop focussed around two working groups: (1) the Ion Source and Separators working group and (2) themore » Radio Frequency Quadrupoles and Linacs working group. The workshop closed with the two working groups summarizing and outlining the tasks for the future. This report documents the proceedings of the workshop and includes the invited review talks, the two summary talks from the working groups and individual contributions from the participants. It is a complete assemblage of state-of-the-art thinking on ion sources, low-{beta}, low(q/A) accelerating structures, e.g. linacs and RFQS, isobar separators, phase-space matching, cyclotrons, etc., as relevant to radioactive beam facilities and the IsoSpin Laboratory. We regret to say that while the fascinating topic of superconducting low-velocity accelerator structure was covered by Dr. K. Shepard during the workshop, we can only reproduce the copies of the transparencies of his talk in the Appendix, since no written manuscript was available at the time of publication of this report. The individual report have been catologed separately elsewhere.« less

  3. The design of the electron beam dump unit of Turkish Accelerator Center (TAC)

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

    Cite, L. H., E-mail: hcite@gantep.edu.tr; Yilmaz, M., E-mail: Mustafa.Yilmaz@gaziantep.edu.tr

    The required simulations of the electron beam interactions for the design of electron beam dump unit for an accelerator which will operate to get two Infra-Red Free Electron Lasers (IR-FEL) covering the range of 3-250 microns is presented in this work. Simulations have been carried out to understand the interactions of a bulk of specially shaped of four different and widely used materials for the dump materials for a 77 pC, 40 MeV, 13 MHz repetition rate e-beam. In the simulation studies dump materials are chosen to absorb the 99% of the beam energy and to restrict the radio-isotope production in themore » bulk of the dump. A Lead shielding also designed around the dump core to prevent the leakage out of the all the emitted secondary radiations, e.g., neutrons, photons. The necessary dump material requirements, for the overall design considerations and the possible radiation originated effects on the dump unit, are discussed and presented.« less

  4. Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures

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

    Byer, Robert L.

    2013-11-07

    The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

  5. Commentary: Precision science and patient-centered care.

    PubMed

    Clancy, Carolyn M

    2011-06-01

    Patient-centered outcomes research (PCOR), also known as comparative effectiveness research, offers new opportunities and challenges for academic health centers (AHCs). The author of this commentary summarizes the contributions of some of the articles in this issue that focus on PCOR, and she emphasizes the unique features of this distinctive type of research, which are longitudinal patient follow-up, the inclusion of patient-reported outcomes, and the dynamic interaction among all stakeholders throughout all phases of research.The author advocates that researchers engaged in comparative effectiveness research make every effort, and explore innovative means, to accelerate the translation of their research findings into practice. The opportunities to close the gaps between what physicians and medical scientists do and what they know, to support clinicians and patients who are working together in order to rapidly identify the best option for a unique individual, and to lead the way in addressing barriers to achieving personalized, patient-centered care should engage key members of AHCs in comparative effectiveness research, so that these institutions become a vital link connecting biomedical innovation and its precision application in diverse communities and populations.

  6. Development of a Lead Slowing Down Spectrometer for fission cross section measurements at LANSCE

    NASA Astrophysics Data System (ADS)

    Rochman, Dimitri; Haight, Robert C.; Wender, Stephen A.; O'Donnell, John M.; Michaudon, Andre; Vieira, Dave J.; Rundberg, Robert S.; Kronenberg, Andreas; Bond, Evelyn; Wilhelmy, Jerry B.; Bredeweg, Todd; Ethvignot, Thierry; Granier, Thierry; Petit, Michael; Danon, Yaron

    2004-05-01

    The Lead Slowing Down Spectrometer (LSDS) recently installed at the Los Alamos Neutron Science Center (LANSCE) consists of a 1.2 meter cube of lead surrounding a tungsten target, which is bombarded by pulses of 800 MeV protons from the Proton Storage Ring (PSR). Neutrons are produced by spallation from the interaction of the proton pulse with the target. The aim of the LSDS is to keep the neutrons inside the lead volume for few hundreds of microseconds and to slow them down by small steps in energy before they leave the spectrometer. The advantage of the LSDS is the large amount of neutrons available in the lead volume compared to traditional time-of-flight experiments. Driving the LSDS with a pulsed proton beam increases the neutron flux per watt of beam power significantly over similar spectrometers driven by electron linear accelerators. The first measurements to characterize the properties of the LSDS are presented.

  7. Accelerated aggregation of donor nitrogen in diamond containing NV centers

    NASA Astrophysics Data System (ADS)

    Lobanov, Sergey; Vins, Victor; Yelisseev, Alexander; Afonin, Dmitry; Blinkov, Alexander; Maximov, Yuriy

    2010-05-01

    The aggregation of donor nitrogen (C centers) into nitrogen pairs (A centers) is considered to be a second-order chemical reaction and the kinetics of this reaction can be written as follows: Kt = 1-- -1- Ct C0 where K is the aggregation rate constant that depends exponentially on temperature and activation energy K = Aexp (- Ea-kT ) and C0 and CT are C center concentrations before and after the aggregation. The activation energy Ea in natural diamonds is equal to 5±0.3 eV. However, it was shown by Vins (2004) that Ea varied in synthetic diamonds depending on Ni concentration from 3 to 6 eV; and in synthetic diamonds containing cobalt the activation energy exceeded 4 eV. The aggregation rate of C centers also increased dramatically in diamonds irradiated with high-energy electrons (Collins, 1980). An HPHT diamond single crystal grown in the Fe-Co-C system using the TGG method was studied. The initial C center concentration determined from the intensity of the 1130 cm-1 IR absorption band was equal to 118 ppm. In order to determine the influence of NV centers on the activation energy of aggregation, the crystal was at first irradiated with high-energy electrons (3MeV, 2×1018cm-2) and annealed in a quartz ampoule in vacuum (8000C, 2 hrs). This led to the formation of over 5 ppm of NV centers. After that the sample was annealed at high temperatures in the argon flow (15300C, 30 minutes). The IR absorption spectra revealed an

  8. Introduction to the Summit Session, "Leading Perspectives in Energy Research", from the Director of the DOE Office of Science, Bill Brinkman (2011 EFRC Summit)

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

    Brinkman, Bill

    2011-05-25

    In this video Bill Brinkman, Director of DOE's Office of Science, introduces the session, "Leading Perspectives in Energy Research," at the 2011 EFRC Summit and Forum. During the introduction of the senior representatives from both the public and private sector, Dr. Brinkman explained the motivation for creating the Energy Frontiers Research Centers program. The 2011 EFRC Summit and Forum brought together the EFRC community and science and policy leaders from universities, national laboratories, industry and government to discuss "Science for our Nation's Energy Future." In August 2009, the Office of Science established 46 Energy Frontier Research Centers. The EFRCs aremore » collaborative research efforts intended to accelerate high-risk, high-reward fundamental research, the scientific basis for transformative energy technologies of the future. These Centers involve universities, national laboratories, nonprofit organizations, and for-profit firms, singly or in partnerships, selected by scientific peer review. They are funded at $2 to $5 million per year for a total planned DOE commitment of $777 million over the initial five-year award period, pending Congressional appropriations. These integrated, multi-investigator Centers are conducting fundamental research focusing on one or more of several “grand challenges” and use-inspired “basic research needs” recently identified in major strategic planning efforts by the scientific community. The purpose of the EFRCs is to integrate the talents and expertise of leading scientists in a setting designed to accelerate research that transforms the future of energy and the environment.« less

  9. Expanding wave solutions of the Einstein equations that induce an anomalous acceleration into the Standard Model of Cosmology.

    PubMed

    Temple, Blake; Smoller, Joel

    2009-08-25

    We derive a system of three coupled equations that implicitly defines a continuous one-parameter family of expanding wave solutions of the Einstein equations, such that the Friedmann universe associated with the pure radiation phase of the Standard Model of Cosmology is embedded as a single point in this family. By approximating solutions near the center to leading order in the Hubble length, the family reduces to an explicit one-parameter family of expanding spacetimes, given in closed form, that represents a perturbation of the Standard Model. By introducing a comoving coordinate system, we calculate the correction to the Hubble constant as well as the exact leading order quadratic correction to the redshift vs. luminosity relation for an observer at the center. The correction to redshift vs. luminosity entails an adjustable free parameter that introduces an anomalous acceleration. We conclude (by continuity) that corrections to the redshift vs. luminosity relation observed after the radiation phase of the Big Bang can be accounted for, at the leading order quadratic level, by adjustment of this free parameter. The next order correction is then a prediction. Since nonlinearities alone could actuate dissipation and decay in the conservation laws associated with the highly nonlinear radiation phase and since noninteracting expanding waves represent possible time-asymptotic wave patterns that could result, we propose to further investigate the possibility that these corrections to the Standard Model might be the source of the anomalous acceleration of the galaxies, an explanation not requiring the cosmological constant or dark energy.

  10. Center for Materials at Irradiation and Mechanical Extremes at LANL (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema

    Michael Nastasi (Director, Center for Materials at Irradiation and Mechanical Extremes); CMIME Staff

    2017-12-09

    'Center for Materials at Irradiation and Mechanical Extremes (CMIME) at LANL' was submitted by CMIME to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. CMIME, an EFRC directed by Michael Nastasi at Los Alamos National Laboratory is a partnership of scientists from four institutions: LANL (lead), Carnegia Mellon University, the University of Illinois at Urbana Champaign, and the Massachusetts Institute of Technology. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.

  11. Focus on: Washington Hospital Center, Biomedical Engineering Department.

    PubMed

    Hughes, J D

    1995-01-01

    The Biomedical Engineering Department of the Washington Hospital Center provides clinical engineering services to an urban 907-bed, tertiary care teaching hospital and a variety of associated healthcare facilities. With an annual budget of over $3,000,000, the 24-person department provides cradle-to-grave support for a host of sophisticated medical devices and imaging systems such as lasers, CT scanners, and linear accelerators as well as traditional patient care instrumentation. Hallmarks of the department include its commitment to customer service and patient care, close collaboration with clinicians and quality assurance teams throughout the hospital system, proactive involvement in all phases of the technology management process, and shared leadership in safety standards with the hospital's risk management group. Through this interactive process, the department has assisted the Center not only in the acquisition of 11,000 active devices with a value of more than $64 million, but also in becoming one of the leading providers of high technology healthcare in the Washington, DC metropolitan area.

  12. The influence of the aquatic environment on the center of pressure, impulses and upper and lower trunk accelerations during gait initiation.

    PubMed

    Marinho-Buzelli, Andresa R; Masani, Kei; Rouhani, Hossein; Barela, Ana M; Fernandes, Gustavo T B; Verrier, Mary C; Popovic, Milos R

    2017-10-01

    Gait initiation is defined as the transition from stationary standing to steady-state walking. Despite the frequent use of therapy pools for training walking in early stages of rehabilitation, none have been reported on the effects of immersion on gait initiation. We aimed to analyze the center of pressure (COP) trajectories, the vertical and anteroposterior impulses and upper and lower trunk accelerations during anticipatory (APA) and execution phases of gait initiation. In the COP trajectory, the execution (EXE) phase was further subdivided in two phases: predominantly mediolateral (EXE1), and predominantly anteroposterior (EXE2). Able-bodied participants initiated gait while standing on a force plate and walked approximately 4 steps following a visual cue. The participants were wearing three inertial sensors placed on the lower and upper trunk, and on the stance shank. Individuals performed 10 trials each on land and in water, in two consecutive days. The lengths and velocities of COP trajectories increased in water compared to land during APA, while the COP length increased and the COP velocity reduced in water during EXE2. The anteroposterior impulses increased in water during EXE. Lower trunk acceleration was smaller in water while the upper trunk acceleration did not differ, resulting in the larger ratio of upper to lower trunk acceleration in water during EXE. Overall, immersion in water increases COP length during gait initiation, and reduces COP velocity during EXE2, indicating a new postural strategy in water. The aquatic medium may be favorable for individuals who need weight support, gradual resistance and a longer time to execute gait initiation. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Upgrading the Digital Electronics of the PEP-II Bunch Current Monitors at the Stanford Linear Accelerator Center

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

    Kline, Josh; /SLAC

    2006-08-28

    The testing of the upgrade prototype for the bunch current monitors (BCMs) in the PEP-II storage rings at the Stanford Linear Accelerator Center (SLAC) is the topic of this paper. Bunch current monitors are used to measure the charge in the electron/positron bunches traveling in particle storage rings. The BCMs in the PEP-II storage rings need to be upgraded because components of the current system have failed and are known to be failure prone with age, and several of the integrated chips are no longer produced making repairs difficult if not impossible. The main upgrade is replacing twelve old (1995)more » field programmable gate arrays (FPGAs) with a single Virtex II FPGA. The prototype was tested using computer synthesis tools, a commercial signal generator, and a fast pulse generator.« less

  14. High Gradient Accelerator Research

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

    Temkin, Richard

    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave coldmore » test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.« less

  15. Insulation Failure of the Linox Defibrillator Lead: A Case Report and Retrospective Review of a Single Center Experience.

    PubMed

    Howe, Andrew J; McKeag, Nicholas A; Wilson, Carol M; Ashfield, Kyle P; Roberts, Michael J

    2015-06-01

    Implantable cardioverter defibrillator (ICD) lead insulation failure and conductor externalization have been increasingly reported. The 7.8F silicon-insulated Linox SD and Linox S ICD leads (Biotronik, Berlin, Germany) were released in 2006 and 2007, respectively, with an estimated 85,000 implantations worldwide. A 39-year-old female suffered an out-of-hospital ventricular fibrillation (VF) arrest with successful resuscitation. An ICD was implanted utilizing a single coil active fixation Linox(Smart) S lead (Biotronik, Berlin, Germany). A device-triggered alert approximately 3 years after implantation confirmed nonphysiological high rate sensing leading to VF detection. A chest X-ray showed an abnormality of the ICD lead and fluoroscopic screening confirmed conductor externalization proximal to the defibrillator coil. In view of the combined electrical and fluoroscopic abnormalities, urgent lead extraction and replacement were performed. A review of Linox (Biotronik) and Vigila (Sorin Group, Milan, Italy) lead implantations within our center (n = 98) identified 3 additional patients presenting with premature lead failure, 2 associated with nonphysiological sensed events and one associated with a significant decrease in lead impedance. All leads were subsequently removed and replaced. This case provides a striking example of insulation failure affecting the Linox ICD lead and, we believe, is the first to demonstrate conductor externalization manifesting both electrical and fluoroscopic abnormalities. © 2015 Wiley Periodicals, Inc.

  16. Berkeley Proton Linear Accelerator

    DOE R&D Accomplishments Database

    Alvarez, L. W.; Bradner, H.; Franck, J.; Gordon, H.; Gow, J. D.; Marshall, L. C.; Oppenheimer, F. F.; Panofsky, W. K. H.; Richman, C.; Woodyard, J. R.

    1953-10-13

    A linear accelerator, which increases the energy of protons from a 4 Mev Van de Graaff injector, to a final energy of 31.5 Mev, has been constructed. The accelerator consists of a cavity 40 feet long and 39 inches in diameter, excited at resonance in a longitudinal electric mode with a radio-frequency power of about 2.2 x 10{sup 6} watts peak at 202.5 mc. Acceleration is made possible by the introduction of 46 axial "drift tubes" into the cavity, which is designed such that the particles traverse the distance between the centers of successive tubes in one cycle of the r.f. power. The protons are longitudinally stable as in the synchrotron, and are stabilized transversely by the action of converging fields produced by focusing grids. The electrical cavity is constructed like an inverted airplane fuselage and is supported in a vacuum tank. Power is supplied by 9 high powered oscillators fed from a pulse generator of the artificial transmission line type.

  17. Laser acceleration

    NASA Astrophysics Data System (ADS)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  18. Kinetics of oil saponification by lead salts in ancient preparations of pharmaceutical lead plasters and painting lead mediums.

    PubMed

    Cotte, M; Checroun, E; Susini, J; Dumas, P; Tchoreloff, P; Besnard, M; Walter, Ph

    2006-12-15

    Lead soaps can be found in archaeological cosmetics as well as in oil paintings, as product of interactions of lead salts with oil. In this context, a better understanding of the formation of lead soaps allows a follow-up of the historical evolution of preparation recipes and provides new insights into conservation conditions. First, ancient recipes of both pharmaceutical lead plasters and painting lead mediums, mixtures of oil and lead salts, were reconstructed. The ester saponification by lead salts is determined by the preparation parameters which were quantified by FT-IR spectrometry. In particular, ATR/FT-IR spectrometer was calibrated by the standard addition method to quantitatively follow the kinetics of this reaction. The influence of different parameters such as temperature, presence of water and choice of lead salts was assessed: the saponification is clearly accelerated by water and heating. This analysis provides chemical explanations to the historical evolution of cosmetic and painting preparation recipes.

  19. Natural Product Libraries to Accelerate the High Throughput Discovery of Therapeutic Leads±

    PubMed Central

    Johnson, Tyler A.; Sohn, Johann; Inman, Wayne D.; Estee, Samarkand A.; Loveridge, Steven T.; Vervoort, Helene C.; Tenney, Karen; Liu, Junke; Ang, Kenny Kean-Hooi; Ratnam, Joseline; Bray, Walter M.; Gassner, Nadine C.; Shen, Young Y.; Lokey, R. Scott; McKerrow, James H.; Boundy-Mills, Kyria; Nukanto, Arif; Kanti, Atit; Julistiono, Heddy; Kardono, Leonardus B. S.; Bjeldanes, Leonard F.; Crews, Phillip

    2011-01-01

    A high throughput (HT) paradigm generating LC-MS-UV-ELSD based natural product libraries to discover compounds with new bioactivities and or molecular structures is presented. To validate this methodology an extract of the Indo Pacific marine sponge Cacospongia mycofijiensis was evaluated using assays involving cytoskeletal profiling, tumor cell lines, and parasites. Twelve known compounds were identified including the latrunculins (1–4, 10), fijianolides (5, 8–9), mycothiazole (11), the aignopsanes (6–7) and sacrotride A (13). Compounds 1–4, 5, 8–11 exhibited bioactivity not previously reported against the parasite T. brucei, while 11 showed selectivity for lymphoma (U937) tumor cell lines. Four new compounds were also discovered including: aignopsanoic acid B (13), apo latrunculin T (14), 20-methoxy-fijianolide A (15) and aignopsane ketal (16). Compounds 13 and 16 represent important derivatives of the aignopsane class, 14 exhibited inhibition of T. brucei without disrupting microfilament assembly and 15 demonstrated modest microtubule stabilizing effects. The use of removable well plate libraries to avoid false positives from extracts enriched with only 1–2 major metabolites is also discussed. Overall, these results highlight the advantages of applying modern methods in natural products-based research to accelerate the HT discovery of therapeutic leads and or new molecular structures using LC-MS-UV-ELSD based libraries. PMID:22129061

  20. Lederman Science Center: Physicists Explain Exhibits

    Science.gov Websites

    Adventures - Calendar - About - FAQ - Fermilab Friends - Fermilab Home Fermilab Office of Education & . Lederman Science Adventures Teacher Resource Center video video video video video Welcome Accelerators Maintainer: ed-webmaster@fnal.gov Lederman Science Education Center Fermilab MS 777 Box 500 Batavia, IL 60510

  1. Preliminary OARE absolute acceleration measurements on STS-50

    NASA Technical Reports Server (NTRS)

    Blanchard, Robert C.; Nicholson, John Y.; Ritter, James

    1993-01-01

    On-orbit Orbital Acceleration Research Experiment (OARE) data on STS-50 was examined in detail during a 2-day time period. Absolute acceleration levels were derived at the OARE location, the orbiter center-of-gravity, and at the STS-50 spacelab Crystal Growth Facility. The tri-axial OARE raw acceleration measurements (i.e., telemetered data) during the interval were filtered using a sliding trimmed mean filter in order to remove large acceleration spikes (e.g., thrusters) and reduce the noise. Twelve OARE measured biases in each acceleration channel during the 2-day interval were analyzed and applied to the filtered data. Similarly, the in situ measured x-axis scale factors in the sensor's most sensitive range were also analyzed and applied to the data. Due to equipment problem(s) on this flight, both y- and z- axis sensitive range scale factors were determined in a separate process (using the OARE maneuver data) and subsequently applied to the data. All known significant low-frequency corrections at the OARE location (i.e., both vertical and horizontal gravity-gradient, and rotational effects) were removed from the filtered data in order to produce the acceleration components at the orbiter's center-of-gravity, which are the aerodynamic signals along each body axes. Results indicate that there is a force of unknown origin being applied to the Orbiter in addition to the aerodynamic forces. The OARE instrument and all known gravitational and electromagnetic forces were reexamined, but none produce the observed effect. Thus, it is tentatively concluded that the Orbiter is creating the environment observed.

  2. Demonstration of the hollow channel plasma wakefield accelerator

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

    Gessner, Spencer J.

    2016-09-17

    A plasma wakefield accelerator is a device that converts the energy of a relativistic particle beam into a large-amplitude wave in a plasma. The plasma wave, or wakefield, supports an enormous electricfield that is used to accelerate a trailing particle beam. The plasma wakefield accelerator can therefore be used as a transformer, transferring energy from a high-charge, low-energy particle beam into a high-energy, low-charge particle beam. This technique may lead to a new generation of ultra-compact, high-energy particle accelerators. The past decade has seen enormous progress in the field of plasma wakefield acceleration with experimental demonstrations of the acceleration ofmore » electron beams by several gigaelectron-volts. The acceleration of positron beams in plasma is more challenging, but also necessary for the creation of a high-energy electron-positron collider. Part of the challenge is that the plasma responds asymmetrically to electrons and positrons, leading to increased disruption of the positron beam. One solution to this problem, first proposed over twenty years ago, is to use a hollow channel plasma which symmetrizes the response of the plasma to beams of positive and negative charge, making it possible to accelerate positrons in plasma without disruption. In this thesis, we describe the theory relevant to our experiment and derive new results when needed. We discuss the development and implementation of special optical devices used to create long plasma channels. We demonstrate for the first time the generation of meter-scale plasma channels and the acceleration of positron beams therein.« less

  3. Light-current-induced acceleration of degradation of methylammonium lead iodide perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Xiang, Yuren; Zhang, Fan; He, Junjie; Lian, Jiarong; Zeng, Pengju; Song, Jun; Qu, Junle

    2018-04-01

    The photo-conversion efficiency of perovskite solar cells (PSCs) has been improved considerably in recent years, but the poor stability of PSCs still prevents their commercialization. In this report, we use the rate of the integrated short-circuit current change (Drate) to investigate the performance degradation kinetics and identify the degradation of PSCs that is accelerated by the light current. The value of Drate increases by an order of magnitude from about 0.02 to 0.35 mA cm-2·min-1 after light-IV testing. The accelerated degradation progress is proven to be dominated by the hydration process and the migration of the iodine ions of the light current. The migration of the iodine ions enhances the hydration process through a chain reaction, enabling the formation of fast diffusion channels for both H2O and O2, which induce the rapid decomposition of the perovskite film and increase the density of the trap state. The X-ray photoelectron spectroscopy measurement data also indicate that the super oxygen may be formed due to the PCBM damage caused by the migration iodine ions. An understanding of the degradation acceleration mechanism would provide an insight into the effect of ion migration on the stability of PSCs.

  4. Radiation from violently accelerated bodies

    NASA Astrophysics Data System (ADS)

    Gerlach, Ulrich H.

    2001-11-01

    A determination is made of the radiation emitted by a linearly uniformly accelerated uncharged dipole transmitter. It is found that, first of all, the radiation rate is given by the familiar Larmor formula, but it is augmented by an amount which becomes dominant for sufficiently high acceleration. For an accelerated dipole oscillator, the criterion is that the center of mass motion become relativistic within one oscillation period. The augmented formula and the measurements which it summarizes presuppose an expanding inertial observation frame. A static inertial reference frame will not do. Secondly, it is found that the radiation measured in the expanding inertial frame is received with 100% fidelity. There is no blueshift or redshift due to the accelerative motion of the transmitter. Finally, it is found that a pair of coherently radiating oscillators accelerating (into opposite directions) in their respective causally disjoint Rindler-coordinatized sectors produces an interference pattern in the expanding inertial frame. Like the pattern of a Young double slit interferometer, this Rindler interferometer pattern has a fringe spacing which is inversely proportional to the proper separation and the proper frequency of the accelerated sources. The interferometer, as well as the augmented Larmor formula, provide a unifying perspective. It joins adjacent Rindler-coordinatized neighborhoods into a single spacetime arena for scattering and radiation from accelerated bodies.

  5. Convergence of the Ponderomotive Guiding Center approximation in the LWFA

    NASA Astrophysics Data System (ADS)

    Silva, Thales; Vieira, Jorge; Helm, Anton; Fonseca, Ricardo; Silva, Luis

    2017-10-01

    Plasma accelerators arose as potential candidates for future accelerator technology in the last few decades because of its predicted compactness and low cost. One of the proposed designs for plasma accelerators is based on Laser Wakefield Acceleration (LWFA). However, simulations performed for such systems have to solve the laser wavelength which is orders of magnitude lower than the plasma wavelength. In this context, the Ponderomotive Guiding Center (PGC) algorithm for particle-in-cell (PIC) simulations is a potent tool. The laser is approximated by its envelope which leads to a speed-up of around 100 times because the laser wavelength is not solved. The plasma response is well understood, and comparison with the full PIC code show an excellent agreement. However, for LWFA, the convergence of the self-injected beam parameters, such as energy and charge, was not studied before and has vital importance for the use of the algorithm in predicting the beam parameters. Our goal is to do a thorough investigation of the stability and convergence of the algorithm in situations of experimental relevance for LWFA. To this end, we perform simulations using the PGC algorithm implemented in the PIC code OSIRIS. To verify the PGC predictions, we compare the results with full PIC simulations. This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant agreement No 653782.

  6. 805 MHz Beta = 0.47 Elliptical Accelerating Structure R & D

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

    S. Bricker; C. Compton; W. Hartung

    2008-09-22

    A 6-cell 805 MHz superconducting cavity for acceleration in the velocity range of about 0.4 to 0.53 times the speed of light was designed. After single-cell prototyping, three 6-cell niobium cavities were fabricated. In vertical RF tests of the 6-cell cavities, the measured quality factors (Q{sub 0}) were between 7 {center_dot} 10{sup 9} and 1.4 {center_dot} 10{sup 10} at the design field (accelerating gradient of 8 to 10 MV/m). A rectangular cryomodule was designed to house 4 cavities per cryomodule. The 4-cavity cryomodule could be used for acceleration of ions in a linear accelerator, with focusing elements between the cryomodules.more » A prototype cryomodule was fabricated to test 2 cavities under realistic operating conditions. Two of the 6-cell cavities were equipped with helium tanks, tuners, and input coupler and installed into the cryomodule. The prototype cryomodule was used to verify alignment, electromagnetic performance, frequency tuning, cryogenic performance, low-level RF control, and control of microphonics.« less

  7. Lead poisoning in children.

    PubMed

    Dapul, Heda; Laraque, Danielle

    2014-08-01

    There is no safe lead level in children. Primary prevention is the most effective way to bring about the complete removal of lead from the environment and eliminate lead poisoning as a public health concern. The National Lead Information Center can be reached via the Internet at www.epa.gov/lead and www.hud.gov/lead, or via phone at 1-800-424-LEAD (5323).

  8. Validation of Force Limited Vibration Testing at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Rice, Chad; Buehrle, Ralph D.

    2003-01-01

    Vibration tests were performed to develop and validate the forced limited vibration testing capability at the NASA Langley Research Center. The force limited vibration test technique has been utilized at the Jet Propulsion Laboratory and other NASA centers to provide more realistic vibration test environments for aerospace flight hardware. In standard random vibration tests, the payload is mounted to a rigid fixture and the interface acceleration is controlled to a specified level based on a conservative estimate of the expected flight environment. In force limited vibration tests, both the acceleration and force are controlled at the mounting interface to compensate for differences between the flexible flight mounting and rigid test fixture. This minimizes the over test at the payload natural frequencies and results in more realistic forces being transmitted at the mounting interface. Force and acceleration response data was provided by NASA Goddard Space Flight Center for a test article that was flown in 1998 on a Black Brant sounding rocket. The measured flight interface acceleration data was used as the reference acceleration spectrum. Using this acceleration spectrum, three analytical methods were used to estimate the force limits. Standard random and force limited vibration tests were performed and the results are compared with the flight data.

  9. Accelerator & Fusion Research Division 1991 summary of activities

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

    Not Available

    1991-12-01

    This report discusses research projects in the following areas: Heavy-ion fusion accelerator research; magnetic fusion energy; advanced light source; center for x-ray optics; exploratory studies; superconducting magnets; and bevalac operations.

  10. Accelerator Fusion Research Division 1991 summary of activities

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

    Berkner, Klaus H.

    1991-12-01

    This report discusses research projects in the following areas: Heavy-ion fusion accelerator research; magnetic fusion energy; advanced light source; center for x-ray optics; exploratory studies; superconducting magnets; and bevalac operations.

  11. Superconducting traveling wave accelerators

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

    Farkas, Z.D.

    1984-11-01

    This note considers the applicability of superconductivity to traveling wave accelerators. Unlike CW operation of a superconducting standing wave or circulating wave accelerator section, which requires improvement factors (superconductor conductivity divided by copper conductivity) of about 10/sup 6/ in order to be of practical use, a SUperconducting TRaveling wave Accelerator, SUTRA, operating in the pulsed mode requires improvement factors as low as about 10/sup 3/, which are attainable with niobium or lead at 4.2K, the temperature of liquid helium at atmospheric pressure. Changing from a copper traveling wave accelerator to SUTRA achieves the following. (1) For a given gradient SUTRAmore » reduces the peak and average power requirements typically by a factor of 2. (2) SUTRA reduces the peak power still further because it enables us to increase the filling time and thus trade pulse width for gradient. (3) SUTRA makes possible a reasonably long section at higher frequencies. (4) SUTRA makes possible recirculation without additional rf average power. 8 references, 6 figures, 1 table.« less

  12. Proceedings of RIKEN BNL Research Center workwhop on RHIC spin

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

    SOFFER,J.

    1999-10-06

    This RHIC Spin Workshop is the 1999 annual meeting of the RHIC Spin Collaboration, and the second to be hosted at Brookhaven and sponsored by the RIKEN BNL Research Center. The previous meetings were at Brookhaven (1998), Marseille (1996), MIT in 1995, Argonne 1994, Tucson in 1991, and the Polarized Collider Workshop at Penn State in 1990. As noted last year, the Center provides a home for combined work on spin by theorists, experimenters, and accelerator physicists. This proceedings, as last year, is a compilation of 1 page summaries and 5 selected transparencies for each speaker. It is designed tomore » be available soon after the workshop is completed. Speakers are welcome to include web or other references for additional material. The RHIC spin program and RHIC are rapidly becoming reality. RHIC has completed its first commissioning run, as described here by Steve Peggs. The first Siberian Snake for spin has been completed and is being installed in RHIC. A new polarized source from KEK and Triumf with over 1 milliampere of polarized H{sup minus} is being installed, described by Anatoli Zelenski. They have had a successful test of a new polarimeter for RHIC, described by Kazu Kurita and Haixin Huang. Spin commissioning is expected next spring (2000), and the first physics run for spin is anticipated for spring 2001. The purpose of the workshop is to get everyone together about once per year and discuss goals of the spin program, progress, problems, and new ideas. They also have many separate regular forums on spin. There are spin discussion sessions every Tuesday, now organized by Naohito Saito and Werner Vogelsang. The spin discussion schedule and copies of presentations are posted on http://riksg01.rhic.bnl.gov/rsc. Speakers and other spinners are encouraged to come to BNL and to lead a discussion on your favorite idea. They also have regular polarimeter and snake meetings on alternate Thursdays, led by Bill McGahern, the lead engineer for the accelerator

  13. "Leading Better Care": An evaluation of an accelerated coaching intervention for clinical nursing leadership development.

    PubMed

    Cable, Stuart; Graham, Edith

    2018-03-30

    Outcomes of an accelerated co-active coaching intervention for senior clinical nursing leadership development. Co-active coaching is characterized by a whole person approach, commitment to deep learning and conscious action through supportive compassionate and courageous coach-coachee partnership. The national leadership capabilities framework, "Step into Leadership", was used for development and evaluation. 116 senior clinical nurse leaders attended one face-to-face induction day and received a total of 3 hours of one-to-one telephone coaching and two virtual peer group facilitated sessions. Evaluation used primarily qualitative descriptive methods with iterative review of emerging themes. Capability mapping indicated self-leadership development as the most frequently cited need. Improvements in self-confidence, capacity for reflection and bringing whole self into the work were reported to deliver enhancement in team and service performance. Co-active coaching supported deep analysis by individuals. Focus on self, rather than behaviours provoked reflection on perspectives, mindsets, beliefs and approaches which can lead to more sustainable behaviour and support service change. Investment in a co-active coaching approach offers bespoke support for clinical leaders to develop self-leadership capability, a precursor to delivering positive impacts on care. © 2018 John Wiley & Sons Ltd.

  14. Some practical observations on the accelerated testing of Nickel-Cadmium Cells

    NASA Technical Reports Server (NTRS)

    Mcdermott, P. P.

    1979-01-01

    A large scale test of 6.0 Ah Nickel-Cadmium Cells conducted at the Naval Weapons Support Center, Crane, Indiana has demonstrated a methodology for predicting battery life based on failure data from cells cycled in an accelerated mode. After examining eight variables used to accelerate failure, it was determined that temperature and depth of discharge were the most reliable and efficient parameters for use in accelerating failure and for predicting life.

  15. Accelerated Innovation Pilot

    NASA Technical Reports Server (NTRS)

    Davis, Jeffrey

    2012-01-01

    Opportunities: I. Engage NASA team (examples) a) Research and technology calls . provide suggestions to AES, HRP, OCT. b) Use NASA@Work to solicit other ideas; (possibly before R+D calls). II. Stimulate collaboration (examples) a) NHHPC. b) Wharton Mack Center for Technological Innovation (Feb 2013). c) International ] DLR ] :envihab (July 2013). d) Accelerated research models . NSF, Myelin Repair Foundation. III. Engage public Prizes (open platform: InnoCentive, yet2.com, NTL; Rice Business Plan, etc.) IV. Use same methods to engage STEM.

  16. Design of four-beam IH-RFQ linear accelerator

    NASA Astrophysics Data System (ADS)

    Ikeda, Shota; Murata, Aki; Hayashizaki, Noriyosu

    2017-09-01

    The multi-beam acceleration method is an acceleration technique for low-energy high-intensity heavy ion beams, which involves accelerating multiple beams to decrease space charge effects, and then integrating these beams by a beam funneling system. At the Tokyo Institute of Technology a two beam IH-RFQ linear accelerator was developed using a two beam laser ion source with direct plasma injection scheme. This system accelerated a carbon ion beam with a current of 108 mA (54 mA/channel × 2) from 5 up to 60 keV/u. In order to demonstrate that a four-beam IH-RFQ linear accelerator is suitable for high-intensity heavy ion beam acceleration, we have been developing a four-beam prototype. A four-beam IH-RFQ linear accelerator consists of sixteen RFQ electrodes (4 × 4 set) with stem electrodes installed alternately on the upper and lower ridge electrodes. As a part of this development, we have designed a four-beam IH-RFQ linear accelerator using three dimensional electromagnetic simulation software and beam tracking simulation software. From these simulation results, we have designed the stem electrodes, the center plate and the side shells by evaluating the RF properties such as the resonance frequency, the power loss and the electric strength distribution between the RFQ electrodes.

  17. "Turn-on" fluorescence detection of lead ions based on accelerated leaching of gold nanoparticles on the surface of graphene.

    PubMed

    Fu, Xiuli; Lou, Tingting; Chen, Zhaopeng; Lin, Meng; Feng, Weiwei; Chen, Lingxin

    2012-02-01

    A novel platform for effective "turn-on" fluorescence sensing of lead ions (Pb(2+)) in aqueous solution was developed based on gold nanoparticle (AuNP)-functionalized graphene. The AuNP-functionalized graphene exhibited minimal background fluorescence because of the extraordinarily high quenching ability of AuNPs. Interestingly, the AuNP-functionalized graphene underwent fluorescence restoration as well as significant enhancement upon adding Pb(2+), which was attributed to the fact that Pb(2+) could accelerate the leaching rate of the AuNPs on graphene surfaces in the presence of both thiosulfate (S(2)O(3)(2-)) and 2-mercaptoethanol (2-ME). Consequently, this could be utilized as the basis for selective detection of Pb(2+). With the optimum conditions chosen, the relative fluorescence intensity showed good linearity versus logarithm concentration of Pb(2+) in the range of 50-1000 nM (R = 0.9982), and a detection limit of 10 nM. High selectivity over common coexistent metal ions was also demonstrated. The practical application had been carried out for determination of Pb(2+) in tap water and mineral water samples. The Pb(2+)-specific "turn-on" fluorescence sensor, based on Pb(2+) accelerated leaching of AuNPs on the surface of graphene, provided new opportunities for highly sensitive and selective Pb(2+) detection in aqueous media.

  18. Center for Materials at Irradiation and Mechanical Extremes at LANL (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

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

    Nastasi, Michael

    "Center for Materials at Irradiation and Mechanical Extremes (CMIME) at LANL" was submitted by CMIME to the "Life at the Frontiers of Energy Research" video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. CMIME, an EFRC directed by Michael Nastasi at Los Alamos National Laboratory is a partnership of scientists from four institutions: LANL (lead), Carnegie Mellon University, the University of Illinois at Urbana-Champaign, and the Massachusetts Institute of Technology. The Office of Basic Energy Sciences in themore » U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.« less

  19. Implantable cardioverter-defibrillator lead failure in children and young adults: a matter of lead diameter or lead design?

    PubMed

    Janson, Christopher M; Patel, Akash R; Bonney, William J; Smoots, Karen; Shah, Maully J

    2014-01-21

    This study aimed to investigate the impact of lead diameter and design on implantable cardioverter-defibrillator (ICD) lead survival in children and young adults. Recent reports have called attention to high rates of lead failure in adults with small-diameter ICD leads, but data in the pediatric population is limited. We reviewed lead performance in consecutive subjects ≤30 years with transvenous right ventricular ICD leads implanted at our center between January 1995 and October 2011. Lead failure was defined as fracture, perforation, or sensing failure necessitating revision. A total of 120 ICD leads were implanted in 101 patients at a mean age of 15.5 ± 4.9 years. There were 47 small-diameter (≤8-F) and 73 standard-diameter (>8-F) leads. During a median follow-up of 28.7 months (interquartile range: 14.4 to 59.2 months), there were 25 lead failures (21% prevalence), with an incidence of 5.6%/year (95% confidence interval: 3.4 to 7.8). Sprint Fidelis (SF) (Medtronic, Inc., Minneapolis, Minnesota) leads had lower 3-year (69% vs. 92%, p < 0.01) and 5-year (44% vs. 86%, p < 0.01) survival probabilities than standard-diameter leads. In multivariate Cox regression, SF design conferred the greatest hazard ratio for lead failure (hazard ratio: 4.42, 95% confidence interval: 1.73 to 11.29, p < 0.01). Age and linear growth were not significantly associated with lead failure. In this single-center pediatric study that evaluated lead diameter, lead design, and patient factors, the SF design conferred the highest risk of lead failure, suggesting that design rather than diameter is the critical issue in ICD lead performance. Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  20. Electron acceleration via magnetic island coalescence

    NASA Astrophysics Data System (ADS)

    Shinohara, I.; Yumura, T.; Tanaka, K. G.; Fujimoto, M.

    2009-06-01

    Electron acceleration via fast magnetic island coalescence that happens as quick magnetic reconnection triggering (QMRT) proceeds has been studied. We have carried out a three-dimensional full kinetic simulation of the Harris current sheet with a large enough simulation run for two magnetic islands coalescence. Due to the strong inductive electric field associated with the non-linear evolution of the lower-hybrid-drift instability and the magnetic island coalescence process observed in the non-linear stage of the collisionless tearing mode, electrons are significantly accelerated at around the neutral sheet and the subsequent X-line. The accelerated meandering electrons generated by the non-linear evolution of the lower-hybrid-drift instability are resulted in QMRT, and QMRT leads to fast magnetic island coalescence. As a whole, the reconnection triggering and its transition to large-scale structure work as an effective electron accelerator.

  1. Effects of byproducts amended lead contaminated urban soils on carrot yield and lead uptake

    USDA-ARS?s Scientific Manuscript database

    Lead (Pb) has been used to produce a large number of materials and manufactured products. In areas with a history of lead paint use, high vehicular traffic and/or areas close to urban and industrial centers, atmospheric lead deposition may be very high. Consequently, a high deposition of lead in u...

  2. Dynamic Geochemistry of Tetraethyl Lead Dust during the 20th Century: Getting the Lead In, Out, and Translational Beyond

    PubMed Central

    2018-01-01

    This commentary provides a brief overview of policy decisions that permitted getting tetraethyl lead (TEL) into petrol; global geochemical lead-dust deposition evidence; 1975 catalytic converter requirements; concern about habitability of cities; a personal perspective on legacy lead research that accelerated getting TEL out of petrol; and translational beyond, including New Orleans pre- vs. post-Hurricane Katrina observations about legacy lead interventions that effectively improve urban children’s health outcomes. PMID:29701636

  3. Accelerator and fusion research division. 1992 Summary of activities

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

    Not Available

    1992-12-01

    This report contains brief discussions on research topics in the following area: Heavy-Ion Fusion Accelerator Research; Magnetic Fusion Energy; Advanced Light Source; Center for Beam Physics; Superconducting Magnets; and Bevalac Operations.

  4. Integrating functional genomics to accelerate mechanistic personalized medicine.

    PubMed

    Tyner, Jeffrey W

    2017-03-01

    The advent of deep sequencing technologies has resulted in the deciphering of tremendous amounts of genetic information. These data have led to major discoveries, and many anecdotes now exist of individual patients whose clinical outcomes have benefited from novel, genetically guided therapeutic strategies. However, the majority of genetic events in cancer are currently undrugged, leading to a biological gap between understanding of tumor genetic etiology and translation to improved clinical approaches. Functional screening has made tremendous strides in recent years with the development of new experimental approaches to studying ex vivo and in vivo drug sensitivity. Numerous discoveries and anecdotes also exist for translation of functional screening into novel clinical strategies; however, the current clinical application of functional screening remains largely confined to small clinical trials at specific academic centers. The intersection between genomic and functional approaches represents an ideal modality to accelerate our understanding of drug sensitivities as they relate to specific genetic events and further understand the full mechanisms underlying drug sensitivity patterns.

  5. High-gradient compact linear accelerator

    DOEpatents

    Carder, B.M.

    1998-05-26

    A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter. 10 figs.

  6. High-gradient compact linear accelerator

    DOEpatents

    Carder, Bruce M.

    1998-01-01

    A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter.

  7. Acceleration Environment of the International Space Station

    NASA Technical Reports Server (NTRS)

    McPherson, Kevin; Kelly, Eric; Keller, Jennifer

    2009-01-01

    Measurement of the microgravity acceleration environment on the International Space Station has been accomplished by two accelerometer systems since 2001. The Microgravity Acceleration Measurement System records the quasi-steady microgravity environment, including the influences of aerodynamic drag, vehicle rotation, and venting effects. Measurement of the vibratory/transient regime, comprised of vehicle, crew, and equipment disturbances, has been accomplished by the Space Acceleration Measurement System-II. Until the arrival of the Columbus Orbital Facility and the Japanese Experiment Module, the location of these sensors, and therefore, the measurement of the microgravity acceleration environment, has been limited to within the United States Laboratory. Japanese Aerospace Exploration Agency has developed a vibratory acceleration measurement system called the Microgravity Measurement Apparatus which will be deployed within the Japanese Experiment Module to make distributed measurements of the Japanese Experiment Module's vibratory acceleration environment. Two Space Acceleration Measurement System sensors from the United States Laboratory will be re-deployed to support vibratory acceleration data measurement within the Columbus Orbital Facility. The additional measurement opportunities resulting from the arrival of these new laboratories allows Principal Investigators with facilities located in these International Space Station research laboratories to obtain microgravity acceleration data in support of their sensitive experiments. The Principal Investigator Microgravity Services project, at NASA Glenn Research Center, in Cleveland, Ohio, has supported acceleration measurement systems and the microgravity scientific community through the processing, characterization, distribution, and archival of the microgravity acceleration data obtained from the International Space Station acceleration measurement systems. This paper summarizes the PIMS capabilities available

  8. Proceedings of: 2005 Particle Acceleration Confence

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

    Henderson, Stuart

    2006-01-01

    The 21st Particle Accelerator Conference, PAC05, took place at the Knoxville Convention Center (KCC) from Monday through Friday, May 16-20, 2005. Sponsored by the American Physical Society (APS), the Institute of Electrics and Electronics Engineers (IEEE) with its subdivision of Nuclear and Plasma Sciences Society (NPSS), the conference was hosted by the Oak Ridge National Laboratory (ORNL) Spallation Neutron Source (SNS) Project and Thomas Jefferson National Accelerator Facility (JLab). The conference was chaired by Norbert Holtkamp, and the Local Organizing Committee was made up of staff from the ORNL SNS Project under the chairmanship of Stuart Henderson. The conference welcomedmore » over 1400 delegates from the United States, Europe, Asia, the Middle East, South America and from as far away as Australia. Almost 1400 papers where processed during the conference and will be published on the Joint Accelerator Conferences Website (JACoW) page.« less

  9. Exploring the mechanical basis for acceleration: pelvic limb locomotor function during accelerations in racing greyhounds (Canis familiaris)

    PubMed Central

    Williams, S. B.; Usherwood, J. R.; Jespers, K.; Channon, A. J.; Wilson, A. M.

    2009-01-01

    Summary Animals in their natural environments are confronted with a regular need to perform rapid accelerations (for example when escaping from predators or chasing prey). Such acceleration requires net positive mechanical work to be performed on the centre of mass by skeletal muscle. Here we determined how pelvic limb joints contribute to the mechanical work and power that are required for acceleration in galloping quadrupeds. In addition, we considered what, if any, biomechanical strategies exist to enable effective acceleration to be achieved. Simultaneous kinematic and kinetic data were collected for racing greyhounds undergoing a range of low to high accelerations. From these data, joint moments and joint powers were calculated for individual hindlimb joints. In addition, the mean effective mechanical advantage (EMA) of the limb and the `gear ratio' of each joint throughout stance were calculated. Greatest increases in joint work and power with acceleration appeared at the hip and hock joints, particularly in the lead limb. Largest increases in absolute positive joint work occurred at the hip, consistent with the hypothesis that quadrupeds power locomotion by torque about the hip. In addition, hindlimb EMA decreased substantially with increased acceleration – a potential strategy to increase stance time and thus ground impulses for a given peak force. This mechanism may also increase the mechanical advantage for applying the horizontal forces necessary for acceleration. PMID:19181903

  10. Translational Partnership Development Lead | Center for Cancer Research

    Cancer.gov

    PROGRAM DESCRIPTION The Frederick National Laboratory for Cancer Research (FNLCR) is a Federally Funded Research and Development Center operated by Leidos Biomedical Research, Inc on behalf of the National Cancer Institute (NCI). The staff of FNLCR support the NCI’s mission in the fight against cancer and HIV/AIDS. Currently we are seeking a Translational Partnership

  11. Microparticle acceleration by a Van de Graaff accelerator and application to space and material sciences

    NASA Astrophysics Data System (ADS)

    Shibata, Hiromi; Kobayashi, Koichi; Iwai, Takeo; Hamabe, Yoshimi; Sasaki, Sho; Hasegawa, Sunao; Yano, Hajime; Fujiwara, Akira; Ohashi, Hideo; Kawamura, Toru; Nogami, Ken-ichi

    2001-01-01

    A microparticle (dust) ion source has been installed in the 3.75 MV Van de Graaff electrostatic accelerator and a new beam line for microparticle experiments has been built at the HIT facility of Research Center for Nuclear Science and Technology, the University of Tokyo. Microparticle acceleration has been successful in obtaining expected velocities of 1-20 km/s or more for micron- or submicron-sized particles. Development of in situ dust detectors on board satellites and spacecraft in the expected mass and velocity range of micrometeoroids and investigation of hypervelocity impact phenomena by using time-of-flight mass spectrometry, impact flash measurement and scanning electron microscope observation for metals, polymers and semiconductors bombarded by micron-sized particles have been started.

  12. AT2 DS II - Accelerator System Design (Part II) - CCC Video Conference

    ScienceCinema

    None

    2017-12-09

    Discussion Session - Accelerator System Design (Part II) Tutors: C. Darve, J. Weisend II, Ph. Lebrun, A. Dabrowski, U. Raich Video Conference with the CERN Control Center. Experts in the field of Accelerator science will be available to answer the students questions. This session will link the CCC and SA (using Codec VC).

  13. Recent results of studies of acceleration of compact toroids

    NASA Astrophysics Data System (ADS)

    Hammer, J. H.; Hartmen, C. W.; Eddleman, J.

    1984-03-01

    The observed gross stability and self-contained structure of compact toroids (CT's) give rise to the possibility, unique among magnetically confined plasmas, of translating CT's from their point of origin over distances many times their own length. This feature has led us to consider magnetic acceleration of CT's to directed kinetic energies much greater than their stored magnetic and thermal energies. A CT accelerator falls in the very broad gap between traditional particle accelerators at one extreme, which are limited in the number of particles per bunch by electrostatic repulsive forces, and mass accelerators such as rail guns at the other extreme, which accelerate many particles but are forced by the stress limitations of solids to far smaller accelerations. A typical CT has about a Coulomb of particles, weighs 10 micrograms and can be accelerated by magnetic forces of several tons, leading to an acceleration on the order of 10(11) gravities.

  14. Quench protection diode irradiation tests by the Texas Accelerator Center

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

    Carcagno, R.; Weichold, M.; Welch, G.

    1986-07-14

    To date considerable progress has been made in the first stage of the TAC program to assess the use of Quench protection diodes (QPD) within the cold region of the SSC superconducting magnets. Our principle goal in this period was to experimentally obtain information that will assist us in designing apparatus for future tests. More specifically, we wished to address the following areas of uncertainty: operational difficulties associated with installing and operating an experiment at a nuclear reactor; diode behavior when subjected to neutron radiation while held close to the temperature of liquid nitrogen; and the extent to which diodesmore » can be annealed by heating them up to 593/degree/K. To gain information in these areas, we performed an irradiation of sixteen Westinghouse diodes at the Texas A and M Nuclear Science Center reactor. In the interest of avoiding the expense and long lead times associated with obtaining new equipment, we used apparatus that was on hand or which could be quickly obtained or constructed. Further tests of the irradiated diodes and analysis of the data already acquired will be continuing for some time, but the results already available will allow us to proceed with designing apparatus for accurate and reliable irradiation testing of diodes. The following is a summary of what we have learned in the three areas mentioned above, some cautions about interpreting the data, and the implications of this new information for our future activities. 14 figs., 1 tab.« less

  15. GeV Electrons due to a Transition from Laser Wakefield Acceleration to Plasma Wakefield Acceleration

    NASA Astrophysics Data System (ADS)

    Mo, M. Z.; Masson-Laborde, P.-E.; Ali, A.; Fourmaux, S.; Lassonde, P.; Kieffer, J.-C.; Rozmus, W.; Teychenné, D.; Fedosejevs, R.

    2014-10-01

    The Laser Wakefield Acceleration (LWFA) experiments performed with the 200 TW laser system located at the Canadian Advanced Laser Light Source facility at INRS, Varennes (Québec) observed at relatively high plasma densities (1 × 1019cm-3) electron bunches of GeV energy gain, more than double of the predicted energy using Lu's scaling law. This energy boost phenomena can be attributed to a transition from LWFA regime to a plasma wakefield acceleration (PWFA) regime. In the first stage, the acceleration mechanism is dominated by the bubble created by the laser in the regime of LWFA, leading to an injection of a large number of electrons. After propagation beyond the depletion length, where the laser pulse is depleted and it can no longer sustain the bubble anymore, the dense bunch of high energy electrons propagating inside the bubble will drive its own wakefield in the PWFA regime that can trap and accelerate a secondary population of electrons up to the GeV level. 3D particle-in-cell simulations support this analysis, and confirm the scenario.

  16. Calculations of the Acceleration of Centrifugal Loading on Adherent Cells

    NASA Astrophysics Data System (ADS)

    Chen, Kang; Song, Yang; Liu, Qing; Zhang, Chunqiu

    2017-07-01

    Studies have shown that the morphology and function of living cells are greatly affected by the state of different high acceleration. Based on the centrifuge, we designed a centrifugal cell loading machine for the mechanical biology of cells under high acceleration loading. For the machine, the feasibility of the experiment was studied by means of constant acceleration or variable acceleration loading in the Petri dish fixture and/or culture flask. Here we analyzed the distribution of the acceleration of the cells with the change of position and size of the culturing device quantitatively. It is obtained that Petri dish fixture and/or culture flask can be used for constant acceleration loading by experiments; the centripetal acceleration of the adherent cells increases with the increase of the distance between the rotor center of the centrifuge and the fixture of the Petri dish and the size of the fixture. It achieves the idea that the general biology laboratory can conduct the study of mechanical biology at high acceleration. It also provides a basis for more accurate study of the law of high acceleration on mechanobiology of cells.

  17. NREL National Bioenergy Center Overview

    ScienceCinema

    Foust, Thomas; Pienkos, Phil; Sluiter, Justin; Magrini, Kim; McMillan, Jim

    2018-01-16

    The demand for clean, sustainable, secure energy is growing... and the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) is answering the call. NREL's National Bioenergy Center is pioneering biofuels research and development and accelerating the pace these technologies move into the marketplace.

  18. ELECTRON ACCELERATION IN CONTRACTING MAGNETIC ISLANDS DURING SOLAR FLARES

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

    Borovikov, D.; Tenishev, V.; Gombosi, T. I.

    Electron acceleration in solar flares is well known to be efficient at generating energetic particles that produce the observed bremsstrahlung X-ray spectra. One mechanism proposed to explain the observations is electron acceleration within contracting magnetic islands formed by magnetic reconnection in the flare current sheet. In a previous study, a numerical magnetohydrodynamic simulation of an eruptive solar flare was analyzed to estimate the associated electron acceleration due to island contraction. That analysis used a simple analytical model for the island structure and assumed conservation of the adiabatic invariants of particle motion. In this paper, we perform the first-ever rigorous integrationmore » of the guiding-center orbits of electrons in a modeled flare. An initially isotropic distribution of particles is seeded in a contracting island from the simulated eruption, and the subsequent evolution of these particles is followed using guiding-center theory. We find that the distribution function becomes increasingly anisotropic over time as the electrons’ energy increases by up to a factor of five, in general agreement with the previous study. In addition, we show that the energized particles are concentrated on the Sunward side of the island, adjacent to the reconnection X-point in the flare current sheet. Furthermore, our analysis demonstrates that the electron energy gain is dominated by betatron acceleration in the compressed, strengthened magnetic field of the contracting island. Fermi acceleration by the shortened field lines of the island also contributes to the energy gain, but it is less effective than the betatron process.« less

  19. Acceleration display system for aircraft zero-gravity research

    NASA Technical Reports Server (NTRS)

    Millis, Marc G.

    1987-01-01

    The features, design, calibration, and testing of Lewis Research Center's acceleration display system for aircraft zero-gravity research are described. Specific circuit schematics and system specifications are included as well as representative data traces from flown trajectories. Other observations learned from developing and using this system are mentioned where appropriate. The system, now a permanent part of the Lewis Learjet zero-gravity program, provides legible, concise, and necessary guidance information enabling pilots to routinely fly accurate zero-gravity trajectories. Regular use of this system resulted in improvements of the Learjet zero-gravity flight techniques, including a technique to minimize later accelerations. Lewis Gates Learjet trajectory data show that accelerations can be reliably sustained within 0.01 g for 5 consecutive seconds, within 0.02 g for 7 consecutive seconds, and within 0.04 g for up to 20 second. Lewis followed the past practices of acceleration measurement, yet focussed on the acceleration displays. Refinements based on flight experience included evolving the ranges, resolutions, and frequency responses to fit the pilot and the Learjet responses.

  20. Using a national archive of patient experience narratives to promote local patient-centered quality improvement: an ethnographic process evaluation of 'accelerated' experience-based co-design.

    PubMed

    Locock, Louise; Robert, Glenn; Boaz, Annette; Vougioukalou, Sonia; Shuldham, Caroline; Fielden, Jonathan; Ziebland, Sue; Gager, Melanie; Tollyfield, Ruth; Pearcey, John

    2014-10-01

    To evaluate an accelerated form of experience-based co-design (EBCD), a type of participatory action research in which patients and staff work together to improve quality; to observe how acceleration affected the process and outcomes of the intervention. An ethnographic process evaluation of an adapted form of EBCD was conducted, including observations, interviews, questionnaires and documentary analysis. Whilst retaining all components of EBCD, the adapted approach replaced local patient interviews with secondary analysis of a national archive of patient experience narratives to create national trigger films; shortened the timeframe; and employed local improvement facilitators. It was tested in intensive care and lung cancer in two English National Health Service (NHS) hospitals. A total of 96 clinical staff (primarily nursing and medical), and 63 patients and family members participated in co-design activities. The accelerated approach proved acceptable to staff and patients; using films of national rather than local narratives did not adversely affect local NHS staff engagement, and may have made the process less threatening or challenging. Local patients felt the national films generally reflected important themes although a minority felt they were more negative than their own experience. However, they served their purpose of 'triggering' discussion between patients and staff, and the resulting 48 co-design (improvement) activities across the four pathways were similar to those in EBCD, but achieved more quickly and at lower cost. Accelerated EBCD offers a rigorous and relatively cost-effective patient-centered quality improvement approach. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  1. Extreme Lagrangian acceleration in confined turbulent flow.

    PubMed

    Kadoch, Benjamin; Bos, Wouter J T; Schneider, Kai

    2008-05-09

    A Lagrangian study of two-dimensional turbulence for two different geometries, a periodic and a confined circular geometry, is presented to investigate the influence of solid boundaries on the Lagrangian dynamics. It is found that the Lagrangian acceleration is even more intermittent in the confined domain than in the periodic domain. The flatness of the Lagrangian acceleration as a function of the radius shows that the influence of the wall on the Lagrangian dynamics becomes negligible in the center of the domain, and it also reveals that the wall is responsible for the increased intermittency. The transition in the Lagrangian statistics between this region, not directly influenced by the walls, and a critical radius which defines a Lagrangian boundary layer is shown to be very sharp with a sudden increase of the acceleration flatness from about 5 to about 20.

  2. Physiological Effects of Acceleration Observed During a Centrifuge Study of Pilot Performance

    NASA Technical Reports Server (NTRS)

    Smedal, Harald A.; Creer, Brent Y.; Wingrove, Rodney C.

    1960-01-01

    An investigation was conducted by the National Aeronautics and Space Administration, Ames Research Center, and the Naval Air Development Center, Aviation Medical Acceleration Laboratory, to study the effects of acceleration on pilot performance and to obtain some meaningful data for use in establishing tolerance to acceleration levels. The flight simulator used in the study was the Johnsville centrifuge operated as a closed loop system. The pilot was required to perform a control task in various sustained acceleration fields typical of those that Might be encountered by a pilot flying an entry vehicle in which he is seated in a forward-facing position. A special restraint system was developed and designed to increase the pilot's tolerance to these accelerations. The results of this study demonstrated that a well-trained subject, such as a test pilot, can adequately carry out a control task during moderately high accelerations for prolonged periods of time. The maximum levels of acceleration tolerated were approximately 6 times that of gravity for approximately 6 minutes, and varied slightly with the acceleration direction. The tolerance runs were in each case terminated by the subject. In all but two instances, the cause was extreme fatigue. On two occasions the subject terminated the run when he "grayed out." Although there were subjective and objective findings involving the visual and cardiovascular systems, the respiratory system yielded the more critical limiting factors. It would appear that these limiting factors were less severe during the "eyeballs-out" accelerations when compared with the "eyeballs-in" accelerations. These findings are explained on the basis of the influence that the inertial forces of acceleration have on the mechanics of respiration. A condensed version of this report was presented at the Annual Meeting of the Aerospace Medical Association, Miami Beach, May 5-11, 1960, in a paper entitled "Ability of Pilots to Perform a Control Task in

  3. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  4. Spatial relationships between lead sources and children's blood lead levels in the urban center of Indianapolis (USA).

    PubMed

    Morrison, Deborah; Lin, Qing; Wiehe, Sarah; Liu, Gilbert; Rosenman, Marc; Fuller, Trevor; Wang, Jane; Filippelli, Gabriel

    2013-04-01

    Urban children remain disproportionately at risk of having higher blood lead levels than their suburban counterparts. The Westside Cooperative Organization (WESCO), located in Marion County, Indianapolis, Indiana, has a history of children with high blood lead levels as well as high soil lead (Pb) values. This study aims at determining the spatial relationship between soil Pb sources and children's blood lead levels. Soils have been identified as a source of chronic Pb exposure to children, but the spatial scale of the source-recipient relationship is not well characterized. Neighborhood-wide analysis of soil Pb distribution along with a furnace filter technique for sampling interior Pb accumulation for selected homes (n = 7) in the WESCO community was performed. Blood lead levels for children aged 0-5 years during the period 1999-2008 were collected. The study population's mean blood lead levels were higher than national averages across all ages, race, and gender. Non-Hispanic blacks and those individuals in the Wishard advantage program had the highest proportion of elevated blood lead levels. The results show that while there is not a direct relationship between soil Pb and children's blood lead levels at a spatial scale of ~100 m, resuspension of locally sourced soil is occurring based on the interior Pb accumulation. County-wide, the largest predictor of elevated blood lead levels is the location within the urban core. Variation in soil Pb and blood lead levels on the community level is high and not predicted by housing stock age or income. Race is a strong predictor for blood lead levels in the WESCO community.

  5. Federally funded comprehensive women's health centers: leading innovation in women's healthcare delivery.

    PubMed

    Bean-Mayberry, Bevanne; Yano, Elizabeth M; Bayliss, Nichole; Navratil, Judith; Weisman, Carol S; Scholle, Sarah Hudson

    2007-11-01

    Women's healthcare has historically been fragmented, given the artificial separation of reproductive care from general medical care. Aiming to advance new care models for delivery of comprehensive, integrated clinical care for women, two federal agencies-the U.S. Department of Health and Human Services (DHHS) and Department of Veterans Affairs (VA)-launched specialized women's health centers (WHCs). Exemplars of comprehensive service delivery, these originally federally funded centers have served as foundations for innovations in delivering comprehensive care to women in diverse practice settings. Little is known, however, about details of their organization, staffing, practice arrangements, and service availability that might inform adoption of similar models in the community. Using comparable key informant surveys, we collected organizational data from the DHHS National Centers of Excellence (CoE) (n = 13) and the original VA comprehensive WHC's (n = 8). We abstracted supplemental data (e.g., academic affiliation) from the 2001 American Hospital Association (AHA) survey. All DHHS and VA women's health programs served urban areas, and nearly all had academic partnerships. DHHS centers had three times the average caseload as did VA centers. Preventive cancer screening and general reproductive services were uniformly available at all centers, although DHHS centers offered extensive reproductive services on-site more frequently, and VA centers more often had on-site mental healthcare. The DHHS and VA comprehensive WHCs share similar missions and comparable organization, education, and clinical services, demonstrating their commitment to reducing fragmented service delivery. Their common structural components present opportunities for further advancing women's quality of care across other systems of care.

  6. The effect of stochastic re-acceleration on the energy spectrum of shock-accelerated protons

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

    Afanasiev, Alexandr; Vainio, Rami; Kocharov, Leon

    2014-07-20

    The energy spectra of particles in gradual solar energetic particle (SEP) events do not always have a power-law form attributed to the diffusive shock acceleration mechanism. In particular, the observed spectra in major SEP events can take the form of a broken (double) power law. In this paper, we study the effect of a process that can modify the power-law spectral form produced by the diffusive shock acceleration: the stochastic re-acceleration of energetic protons by enhanced Alfvénic turbulence in the downstream region of a shock wave. There are arguments suggesting that this process can be important when the shock propagatesmore » in the corona. We consider a coronal magnetic loop traversed by a shock and perform Monte Carlo simulations of interactions of shock-accelerated protons with Alfvén waves in the loop. The wave-particle interactions are treated self-consistently, so the finiteness of the available turbulent energy is taken into account. The initial energy spectrum of particles is taken to be a power law. The simulations reveal that the stochastic re-acceleration leads either to the formation of a spectrum that is described in a wide energy range by a power law (although the resulting power-law index is different from the initial one) or to a broken power-law spectrum. The resulting spectral form is determined by the ratio of the energy density of shock-accelerated protons to the wave energy density in the shock's downstream region.« less

  7. Radiation from Accelerated Particles in Shocks and Reconnections

    NASA Technical Reports Server (NTRS)

    Nishikawa, K. I.; Choi, E. J.; Min, K. W.; Niemiec, J.; Zhang, B.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Nordlund, A.; Frederiksen, J.; hide

    2012-01-01

    Plasma instabilities are responsible not only for the onset and mediation of collisionless shocks but also for the associated acceleration of particles. We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electrons transverse deflection and, more generally, relativistic acceleration behind the shock. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. Our initial results of a jet-ambient interaction with anti-parallelmagnetic fields show pile-up of magnetic fields at the colliding shock, which may lead to reconnection and associated particle acceleration. We will investigate the radiation in a transient stage as a possible generation mechanism of precursors of prompt emission. In our simulations we calculate the radiation from electrons in the shock region. The detailed properties of this radiation are important for understanding the complex time evolution and spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  8. Radiosurgery with a linear accelerator. Methodological aspects.

    PubMed

    Betti, O O; Galmarini, D; Derechinsky, V

    1991-01-01

    Based on the concepts of Leksell and on recommendations of different Swedish physicists on the use of linear accelerator for radiosurgical use, we developed a new methodology coupling the Talairach stereotactic system with a commercial linac. Anatomical facts encouraged us to use coronal angles of irradiation employing the angular displacement of the linac above the horizontal plane. Different coronal planes are obtained by rotation of the stereotactic frame. The center of the irradiated target coincides with the irradiation and rotation center of the linear accelerator. Multiple targets can be irradiated in the same session. We use as recommended a secondary collimator in heavy alloy. Special software was prepared after different dosimetric controls. The use of a PC allows us to employ 1-6 targets and different collimators to displace the isocenters in order to obtain geometrical isodose modification, and to change the value of each irradiation arc or portions of each arc in some minutes. Simple or sophisticated neurosurgical strategies can be applied in the treatment of frequently irregular shape and volume AVMs.

  9. Gravity Acceleration and Gravity Paradox

    NASA Astrophysics Data System (ADS)

    Hanyongquan, Han; Yuteng, Tang

    2017-10-01

    The magnitude of the gravitational acceleration of the earth is derived from low of universal gravitation. If the size and mass of the gravitational force are proportional to any situation, then the celestial surface gravity is greater than the celestial center near the gravity, and objective facts do not match. Specific derivation method, F = GMm / R2 = mg, g = GM/R2 . c / Ú, G is the gravitational constant, M is the mass of the earth, and finally the g = 9.8 m/s 2 is obtained. We assume that the earth is a standard positive sphere, the earth's volume V = 4 ΠR3/3, assuming that the earth's density is ρ, then M = ρ 4 ΠR3/3 .. c / Ú, the c / Ú into c / Ú get: g = G ρ4 ΠR / 3 .. c / Û, the density of the earth is constant. Careful analysis of the formula c / Û The result of this calculation, we can reach conclusion the gravity acceleration g and the radius of the earth is proportional. In addition to the radius of the Earth c / U the right is constant, That is, the Earth's Gravity acceleration of the outer layer of the earth is greater than the Earth's Gravity acceleration of Inner layer. We are in High School, Huairou District, Beijing, China Author: hanyongquan tangyuteng TEL: 15611860790, 15810953809.

  10. Controllability in Multi-Stage Laser Ion Acceleration

    NASA Astrophysics Data System (ADS)

    Kawata, S.; Kamiyama, D.; Ohtake, Y.; Barada, D.; Ma, Y. Y.; Kong, Q.; Wang, P. X.; Gu, Y. J.; Li, X. F.; Yu, Q.

    2015-11-01

    The present paper shows a concept for a future laser ion accelerator, which should have an ion source, ion collimators, ion beam bunchers and ion post acceleration devices. Based on the laser ion accelerator components, the ion particle energy and the ion energy spectrum are controlled, and a future compact laser ion accelerator would be designed for ion cancer therapy or for ion material treatment. In this study each component is designed to control the ion beam quality. The energy efficiency from the laser to ions is improved by using a solid target with a fine sub-wavelength structure or a near-critical density gas plasma. The ion beam collimation is performed by holes behind the solid target or a multi-layered solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching are successfully realized by a multi-stage laser-target interaction. A combination of each component provides a high controllability of the ion beam quality to meet variable requirements in various purposes in the laser ion accelerator. The work was partly supported by MEXT, JSPS, ASHULA project/ ILE, Osaka University, CORE (Center for Optical Research and Education, Utsunomiya University, Japan), Fudan University and CDI (Creative Dept. for Innovation) in CCRD, Utsunomiya University.

  11. Bacterial cells enhance laser driven ion acceleration

    PubMed Central

    Dalui, Malay; Kundu, M.; Trivikram, T. Madhu; Rajeev, R.; Ray, Krishanu; Krishnamurthy, M.

    2014-01-01

    Intense laser produced plasmas generate hot electrons which in turn leads to ion acceleration. Ability to generate faster ions or hotter electrons using the same laser parameters is one of the main outstanding paradigms in the intense laser-plasma physics. Here, we present a simple, albeit, unconventional target that succeeds in generating 700 keV carbon ions where conventional targets for the same laser parameters generate at most 40 keV. A few layers of micron sized bacteria coating on a polished surface increases the laser energy coupling and generates a hotter plasma which is more effective for the ion acceleration compared to the conventional polished targets. Particle-in-cell simulations show that micro-particle coated target are much more effective in ion acceleration as seen in the experiment. We envisage that the accelerated, high-energy carbon ions can be used as a source for multiple applications. PMID:25102948

  12. Implementation of a 3D version of ponderomotive guiding center solver in particle-in-cell code OSIRIS

    NASA Astrophysics Data System (ADS)

    Helm, Anton; Vieira, Jorge; Silva, Luis; Fonseca, Ricardo

    2016-10-01

    Laser-driven accelerators gained an increased attention over the past decades. Typical modeling techniques for laser wakefield acceleration (LWFA) are based on particle-in-cell (PIC) simulations. PIC simulations, however, are very computationally expensive due to the disparity of the relevant scales ranging from the laser wavelength, in the micrometer range, to the acceleration length, currently beyond the ten centimeter range. To minimize the gap between these despair scales the ponderomotive guiding center (PGC) algorithm is a promising approach. By describing the evolution of the laser pulse envelope separately, only the scales larger than the plasma wavelength are required to be resolved in the PGC algorithm, leading to speedups in several orders of magnitude. Previous work was limited to two dimensions. Here we present the implementation of the 3D version of a PGC solver into the massively parallel, fully relativistic PIC code OSIRIS. We extended the solver to include periodic boundary conditions and parallelization in all spatial dimensions. We present benchmarks for distributed and shared memory parallelization. We also discuss the stability of the PGC solver.

  13. Quantum localization for a kicked rotor with accelerator mode islands.

    PubMed

    Iomin, A; Fishman, S; Zaslavsky, G M

    2002-03-01

    Dynamical localization of classical superdiffusion for the quantum kicked rotor is studied in the semiclassical limit. Both classical and quantum dynamics of the system become more complicated under the conditions of mixed phase space with accelerator mode islands. Recently, long time quantum flights due to the accelerator mode islands have been found. By exploration of their dynamics, it is shown here that the classical-quantum duality of the flights leads to their localization. The classical mechanism of superdiffusion is due to accelerator mode dynamics, while quantum tunneling suppresses the superdiffusion and leads to localization of the wave function. Coupling of the regular type dynamics inside the accelerator mode island structures to dynamics in the chaotic sea proves increasing the localization length. A numerical procedure and an analytical method are developed to obtain an estimate of the localization length which, as it is shown, has exponentially large scaling with the dimensionless Planck's constant (tilde)h<1 in the semiclassical limit. Conditions for the validity of the developed method are specified.

  14. Performance Theory of Diagonal Conducting Wall MHD Accelerators

    NASA Technical Reports Server (NTRS)

    Litchford, R. J.

    2003-01-01

    The theoretical performance of diagonal conducting wall crossed field accelerators is examined on the basis of an infinite segmentation assumption using a cross-plane averaged generalized Ohm's law for a partially ionized gas, including ion slip. The desired accelerator performance relationships are derived from the cross-plane averaged Ohm's law by imposing appropriate configuration and loading constraints. A current dependent effective voltage drop model is also incorporated to account for cold-wall boundary layer effects including gasdynamic variations, discharge constriction, and electrode falls. Definition of dimensionless electric fields and current densities lead to the construction of graphical performance diagrams, which further illuminate the rudimentary behavior of crossed field accelerator operation.

  15. Energy Frontier Research Centers: A View from Senior EFRC Representatives (2011 EFRC Summit, panel session)

    ScienceCinema

    Drell, Persis [SLAC National Accelerator Lab., Menlo Park, CA (United States); Armstrong, Neal [Univ. of Arizona, Tucson, AZ (United States); Carter, Emily [Princeton Univ., NJ (United States); DePaolo, Don [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gunnoe, Brent [Univ. of Virginia, Charlottesville, VA (United States)

    2018-04-26

    A distinguished panel of scientists from the EFRC community provide their perspective on the importance of EFRCs for addressing critical energy needs at the 2011 EFRC Summit. Persis Drell, Director at SLAC, served as moderator. Panel members are Neal Armstrong (Director of the Center for Interface Science: Solar Electric Materials, led by the University of Arizona), Emily Carter (Co-Director of the Combustion EFRC, led by Princeton University. She is also Team Leader of the Heterogeneous Functional Materials Center, led by the University of South Caroline), Don DePaolo (Director of the Center for Nanoscale Control of Geologic CO2, led by LBNL), and Brent Gunnoe (Director of the Center for Catalytic Hydrocarbon Functionalization, led by the University of Virginia). The 2011 EFRC Summit and Forum brought together the EFRC community and science and policy leaders from universities, national laboratories, industry and government to discuss "Science for our Nation's Energy Future." In August 2009, the Office of Science established 46 Energy Frontier Research Centers. The EFRCs are collaborative research efforts intended to accelerate high-risk, high-reward fundamental research, the scientific basis for transformative energy technologies of the future. These Centers involve universities, national laboratories, nonprofit organizations, and for-profit firms, singly or in partnerships, selected by scientific peer review. They are funded at $2 to $5 million per year for a total planned DOE commitment of $777 million over the initial five-year award period, pending Congressional appropriations. These integrated, multi-investigator Centers are conducting fundamental research focusing on one or more of several “grand challenges” and use-inspired “basic research needs” recently identified in major strategic planning efforts by the scientific community. The purpose of the EFRCs is to integrate the talents and expertise of leading scientists in a setting

  16. Energy Frontier Research Centers: A View from Senior EFRC Representatives (2011 EFRC Summit, panel session)

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

    Drell, Persis; Armstrong, Neal; Carter, Emily

    2011-05-25

    A distinguished panel of scientists from the EFRC community provide their perspective on the importance of EFRCs for addressing critical energy needs at the 2011 EFRC Summit. Persis Drell, Director at SLAC, served as moderator. Panel members are Neal Armstrong (Director of the Center for Interface Science: Solar Electric Materials, led by the University of Arizona), Emily Carter (Co-Director of the Combustion EFRC, led by Princeton University. She is also Team Leader of the Heterogeneous Functional Materials Center, led by the University of South Caroline), Don DePaolo (Director of the Center for Nanoscale Control of Geologic CO2, led by LBNL),more » and Brent Gunnoe (Director of the Center for Catalytic Hydrocarbon Functionalization, led by the University of Virginia). The 2011 EFRC Summit and Forum brought together the EFRC community and science and policy leaders from universities, national laboratories, industry and government to discuss "Science for our Nation's Energy Future." In August 2009, the Office of Science established 46 Energy Frontier Research Centers. The EFRCs are collaborative research efforts intended to accelerate high-risk, high-reward fundamental research, the scientific basis for transformative energy technologies of the future. These Centers involve universities, national laboratories, nonprofit organizations, and for-profit firms, singly or in partnerships, selected by scientific peer review. They are funded at $2 to $5 million per year for a total planned DOE commitment of $777 million over the initial five-year award period, pending Congressional appropriations. These integrated, multi-investigator Centers are conducting fundamental research focusing on one or more of several “grand challenges” and use-inspired “basic research needs” recently identified in major strategic planning efforts by the scientific community. The purpose of the EFRCs is to integrate the talents and expertise of leading scientists in a setting designed

  17. Fully Implict Magneto-hydrodynamics Simulations of Coaxial Plasma Accelerators

    DOE PAGES

    Subramaniam, Vivek; Raja, Laxminarayan L.

    2017-01-05

    The resistive Magneto-Hydrodynamic (MHD) model describes the behavior of a strongly ionized plasma in the presence of external electric and magnetic fields. We developed a fully implicit MHD simulation tool to solve the resistive MHD governing equations in the context of a cell-centered finite-volume scheme. The primary objective of this study is to use the fully-implicit algorithm to obtain insights into the plasma acceleration and jet formation processes in Coaxial Plasma accelerators; electromagnetic acceleration devices that utilize self-induced magnetic fields to accelerate thermal plasmas to large velocities. We also carry out plasma-surface simulations in order to study the impact interactionsmore » when these high velocity plasma jets impinge on target material surfaces. Scaling studies are carried out to establish some basic functional relationships between the target-stagnation conditions and the current discharged between the coaxial electrodes.« less

  18. MEMS-based, RF-driven, compact accelerators

    NASA Astrophysics Data System (ADS)

    Persaud, A.; Seidl, P. A.; Ji, Q.; Breinyn, I.; Waldron, W. L.; Schenkel, T.; Vinayakumar, K. B.; Ni, D.; Lal, A.

    2017-10-01

    Shrinking existing accelerators in size can reduce their cost by orders of magnitude. Furthermore, by using radio frequency (RF) technology and accelerating ions in several stages, the applied voltages can be kept low paving the way to new ion beam applications. We make use of the concept of a Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) and have previously shown the implementation of its basic components using printed circuit boards, thereby reducing the size of earlier MEQALACs by an order of magnitude. We now demonstrate the combined integration of these components to form a basic accelerator structure, including an initial beam-matching section. In this presentation, we will discuss the results from the integrated multi-beam ion accelerator and also ion acceleration using RF voltages generated on-board. Furthermore, we will show results from Micro-Electro-Mechanical Systems (MEMS) fabricated focusing wafers, which can shrink the dimension of the system to the sub-mm regime and lead to cheaper fabrication. Based on these proof-of-concept results we outline a scaling path to high beam power for applications in plasma heating in magnetized target fusion and in neutral beam injectors for future Tokamaks. This work was supported by the Office of Science of the US Department of Energy through the ARPA-e ALPHA program under contracts DE-AC02-05CH11231.

  19. Accelerant-related burns and drug abuse: Challenging combination.

    PubMed

    Leung, Leslie T F; Papp, Anthony

    2018-05-01

    Accelerants are flammable substances that may cause explosion when added to existing fires. The relationships between drug abuse and accelerant-related burns are not well elucidated in the literature. Of these burns, a portion is related to drug manufacturing, which have been shown to be associated with increased burn complications. 1) To evaluate the demographics and clinical outcomes of accelerant-related burns in a Provincial Burn Centre. 2) To compare the clinical outcomes with a control group of non-accelerant related burns. 3) To analyze a subgroup of patients with history of drug abuse and drug manufacturing. Retrospective case control study. Patient data associated with accelerant-related burns from 2009 to 2014 were obtained from the British Columbia Burn Registry. These patients were compared with a control group of non-accelerant related burns. Clinical outcomes that were evaluated include inhalational injury, ICU length of stay, ventilator support, surgeries needed, and burn complications. Chi-square test was used to evaluate categorical data and Student's t-test was used to evaluate mean quantitative data with the p value set at 0.05. A logistic regression model was used to evaluate factors affecting burn complications. Accelerant-related burns represented 28.2% of all burn admissions (N=532) from 2009 to 2014. The accelerant group had higher percentage of patients with history of drug abuse and was associated with higher TBSA burns, ventilator support, ICU stay and pneumonia rates compared to the non-accelerant group. Within the accelerant group, there was no difference in clinical outcomes amongst people with or without history of drug abuse. Four cases were associated with methamphetamine manufacturing, all of which underwent ICU stay and ventilator support. Accelerant-related burns cause significant burden to the burn center. A significant proportion of these patients have history of drug abuse. Copyright © 2017 Elsevier Ltd and ISBI. All rights

  20. The Center for Material Science of Nuclear Fuel (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema

    Allen, Todd (Director, Center for Material Science of Nuclear Fuel); CMSNF Staff

    2017-12-09

    'The Center for Material Science of Nuclear Fuel (CMSNF)' was submitted by the CMSNF to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. CMSNF, an EFRC directed by Todd Allen at the Idaho National Laboratory is a partnership of scientists from six institutions: INL (lead), Colorado School of Mines, University of Florida, Florida State University, Oak Ridge National Laboratory, and the University of Wisconsin at Madison. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges. The mission of the Center for Materials Science of Nuclear Fuels is 'to achieve a first-principles based understanding of the effect of irradiation-induced defects and microstructures on thermal transport in oxide nuclear fuels.' Research topics are: phonons, thermal conductivity, nuclear, extreme environment, radiation effects, defects, and matter by design.

  1. The Center for Material Science of Nuclear Fuel (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

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

    Adam, David

    "The Center for Materials Science of Nuclear Fuels (CMSNF)" was submitted by the CMSNF to the "Life at the Frontiers of Energy Research" video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. CMSNF, an EFRC directed by Todd Allen at the Idaho National Laboratory is a partnership of scientists from five institutions: INL (lead), University of Florida, Oak Ridge National Laboratory, Purdue University and the University of Wisconsin at Madison. The Office of Basic Energy Sciences in themore » U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges. The mission of the Center for Materials Science of Nuclear Fuels (CMSNF) is 'to achieve a first-principles based understanding of the effect of irradiation-induced defects and microstructures on thermal transport in oxide nuclear fuels.' Research topics are: phonons, thermal conductivity, nuclear, extreme environment, radiation effects, defects, and matter by design.« less

  2. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  3. View of new centrifuge at Flight Acceleration Facility

    NASA Technical Reports Server (NTRS)

    1966-01-01

    View of the new centrifuge at the Manned Spacecraft Center (MSC), located in the Flight Acceleration Facility, bldg 29. The 50-ft. arm can swing the three man gondola to create g-forces astronauts will experience during controlled flight and during reentry. The centrifuge was designed primarily for training Apollo astronauts.

  4. Plasma development in the accelerator of a 2-kJ focus discharge.

    PubMed

    Fischer, H; Haering, K H

    1979-07-01

    Optical image structures from early breakdown ( approximately 200 nsec) to focus formation (~1300 nsec) in 3 Torr hydrogen were studied by means of 2 image converter shutters having 50-nsec and 10-nsec exposure. Space charge limited cathode spots at the outer electrode (OE)-spoke-shaped positive columns across the gap-and an extended electron cloud along the center electrode (CE) determine the current flow during early breakdown. Ionization increases exponentially within the center gap plasma. This is separated from the CE by a pattern of anode drop filaments. Filament structures grow into the z-axis accelerated current sheath, which in addition carries the early spoke pattern. The sheath appears homogeneous after leaving the accelerator exit.

  5. Pulsed Inductive Plasma Acceleration: Performance Optimization Criteria

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.

    2014-01-01

    Optimization criteria for pulsed inductive plasma acceleration are developed using an acceleration model consisting of a set of coupled circuit equations describing the time-varying current in the thruster and a one-dimensional momentum equation. The model is nondimensionalized, resulting in the identification of several scaling parameters that are varied to optimize the performance of the thruster. The analysis reveals the benefits of underdamped current waveforms and leads to a performance optimization criterion that requires the matching of the natural period of the discharge and the acceleration timescale imposed by the inertia of the working gas. In addition, the performance increases when a greater fraction of the propellant is initially located nearer to the inductive acceleration coil. While the dimensionless model uses a constant temperature formulation in calculating performance, the scaling parameters that yield the optimum performance are shown to be relatively invariant if a self-consistent description of energy in the plasma is instead used.

  6. Performance of some miniature pressure transducers subjected to high rotational speeds and centripetal accelerations

    NASA Technical Reports Server (NTRS)

    Minkin, H. L.

    1976-01-01

    The performance characteristics of several miniature pressure transducers were determined at centripetal accelerations up to 11,200 g's at a rotational speed of 23,000 rpm. The variation in centripetal acceleration was produced by changing radial position of the transducer relative to the center of rotation. Residual zero outputs and transducer sensitivities were determined at 23,000 rpm and compared with those determined at 0 rpm. The actual pressures at the various transducer locations differ from the center line impressed pressures due to a rotational effect. Corrections for this effect were made. A brief description of the test apparatus is included.

  7. Initiation of combustion in the thermally choked ram accelerator

    NASA Technical Reports Server (NTRS)

    Bruckner, A. P.; Burnham, E. A.; Knowlen, C.; Hertzberg, A.; Bogdanoff, D. W.

    1992-01-01

    The methodology for initiating stable combustion in a ram accelerator operating in the thermally choked mode is presented in this paper. The ram accelerator is a high velocity ramjet-in-tube projectile launcher whose principle of operation is similar to that of an airbreathing ramjet. The subcaliber projectile travels supersonically through a stationary tube filled with a premixed combustible gas mixture. In the thermally choked propulsion mode subsonic combustion takes place behind the base of the projectile and leads to thermal choking, which stabilizes a normal shock system on the projectile, thus producing forward thrust. Projectiles with masses in the 45-90 g range have been accelerated to velocities up to 2650 m/sec in a 38 mm bore, 16 m long accelerator tube. Operation of the ram accelerator is started by injecting the projectile into the accelerator tube at velocities in the 700 - 1300 m/sec range by means of a conventional gas gun. A specially designed obturator, which seals the bore of the gun during this initial acceleration, enters the ram accelerator together with the projectile. The interaction of the obturator with the propellant gas ignites the gas mixture and establishes stable combustion behind the projectile.

  8. Fluid Physics in a Fluctuating Acceleration Environment

    NASA Technical Reports Server (NTRS)

    Thomson, J. Ross; Drolet, Francois; Vinals, Jorge

    1996-01-01

    We summarize several aspects of an ongoing investigation of the effects that stochastic residual accelerations (g-jitter) onboard spacecraft can have on experiments conducted in a microgravity environment. The residual acceleration field is modeled as a narrow band noise, characterized by three independent parameters: intensity (g(exp 2)), dominant angular frequency Omega, and characteristic correlation time tau. Realistic values for these parameters are obtained from an analysis of acceleration data corresponding to the SL-J mission, as recorded by the SAMS instruments. We then use the model to address the random motion of a solid particle suspended in an incompressible fluid subjected to such random accelerations. As an extension, the effect of jitter on coarsening of a solid-liquid mixture is briefly discussed, and corrections to diffusion controlled coarsening evaluated. We conclude that jitter will not be significant in the experiment 'Coarsening of solid-liquid mixtures' to be conducted in microgravity. Finally, modifications to the location of onset of instability in systems driven by a random force are discussed by extending the standard reduction to the center manifold to the stochastic case. Results pertaining to time-modulated oscillatory convection are briefly discussed.

  9. The FAST (FRC Acceleration Space Thruster) Experiment

    NASA Technical Reports Server (NTRS)

    Martin, Adam; Eskridge, R.; Lee, M.; Richeson, J.; Smith, J.; Thio, Y. C. F.; Slough, J.; Rodgers, Stephen L. (Technical Monitor)

    2001-01-01

    The Field Reverse Configuration (FRC) is a magnetized plasmoid that has been developed for use in magnetic confinement fusion. Several of its properties suggest that it may also be useful as a thruster for in-space propulsion. The FRC is a compact toroid that has only poloidal field, and is characterized by a high plasma beta = (P)/(B (sup 2) /2Mu0), the ratio of plasma pressure to magnetic field pressure, so that it makes efficient use of magnetic field to confine a plasma. In an FRC thruster, plasmoids would be repetitively formed and accelerated to high velocity; velocities of = 250 km/s (Isp = 25,000s) have already been achieved in fusion experiments. The FRC is inductively formed and accelerated, and so is not subject to the problem of electrode erosion. As the plasmoid may be accelerated over an extended length, it can in principle be made very efficient. And the achievable jet powers should be scalable to the MW range. A 10 kW thruster experiment - FAST (FRC Acceleration Space Thruster) has just started at the Marshall Space Flight Center. The design of FAST and the status of construction and operation will be presented.

  10. Overview of graduate training program of John Adams Institute for Accelerator Science

    NASA Astrophysics Data System (ADS)

    Seryi, Andrei

    The John Adams Institute for Accelerator Science is a center of excellence in the UK for advanced and novel accelerator technology, providing expertise, research, development and training in accelerator techniques, and promoting advanced accelerator applications in science and society. We work in JAI on design of novel light sources upgrades of 3-rd generation and novel FELs, on plasma acceleration and its application to industrial and medical fields, on novel energy recovery compact linacs and advanced beam diagnostics, and many other projects. The JAI is based on three universities - University of Oxford, Imperial College London and Royal Holloway University of London. Every year 6 to 10 accelerators science experts, trained via research on cutting edge projects, defend their PhD thesis in JAI partner universities. In this presentation we will overview the research and in particular the highly successful graduate training program in JAI.

  11. Studying astrophysical particle acceleration with laser-driven plasmas

    NASA Astrophysics Data System (ADS)

    Fiuza, Frederico

    2016-10-01

    The acceleration of non-thermal particles in plasmas is critical for our understanding of explosive astrophysical phenomena, from solar flares to gamma ray bursts. Particle acceleration is thought to be mediated by collisionless shocks and magnetic reconnection. The microphysics underlying these processes and their ability to efficiently convert flow and magnetic energy into non-thermal particles, however, is not yet fully understood. By performing for the first time ab initio 3D particle-in-cell simulations of the interaction of both magnetized and unmagnetized laser-driven plasmas, it is now possible to identify the optimal parameters for the study of particle acceleration in the laboratory relevant to astrophysical scenarios. It is predicted for the Omega and NIF laser conditions that significant non-thermal acceleration can occur during magnetic reconnection of laser-driven magnetized plasmas. Electrons are accelerated by the electric field near the X-points and trapped in contracting magnetic islands. This leads to a power-law tail extending to nearly a hundred times the thermal energy of the plasma and that contains a large fraction of the magnetic energy. The study of unmagnetized interpenetrating plasmas also reveals the possibility of forming collisionless shocks mediated by the Weibel instability on NIF. Under such conditions, both electrons and ions can be energized by scattering out of the Weibel-mediated turbulence. This also leads to power-law spectra that can be detected experimentally. The resulting experimental requirements to probe the microphysics of plasma particle acceleration will be discussed, paving the way for the first experiments of these important processes in the laboratory. As a result of these simulations and theoretical analysis, there are new experiments being planned on the Omega, NIF, and LCLS laser facilities to test these theoretical predictions. This work was supported by the SLAC LDRD program and DOE Office of Science, Fusion

  12. Lead.

    PubMed

    Bellinger, David C

    2004-04-01

    Children differ from adults in the relative importance of lead sources and pathways, lead metabolism, and the toxicities expressed. The central nervous system effects of lead on children seem not to be reversible. Periods of enhanced vulnerability within childhood have not consistently been identified. The period of greatest vulnerability might be endpoint specific, perhaps accounting for the failure to identify a coherent "behavioral signature" for lead toxicity. The bases for the substantial individual variability in vulnerability to lead are uncertain, although they might include genetic polymorphisms and contextual factors. The current Centers for Disease Control and Prevention screening guideline of 10 micro g/dL is a risk management tool and should not be interpreted as a threshold for toxicity. No threshold has been identified, and some data are consistent with effects well below 10. Historically, most studies have concentrated on neurocognitive effects of lead, but higher exposures have recently been associated with morbidities such as antisocial behavior and delinquency. Studies of lead toxicity in experimental animal models are critical to the interpretation of nonexperimental human studies, particularly in addressing the likelihood that associations observed in the latter studies can be attributed to residual confounding. Animal models are also helpful in investigating the behavioral and neurobiological mechanisms of the functional deficits observed in lead-exposed humans. Studies of adults who have been exposed to lead are of limited use in understanding childhood lead toxicity because developmental and acquired lead exposure differ in terms of the maturity of the organs affected, the presumed mechanisms of toxicity, and the forms in which toxicities are expressed.

  13. Undergraduate Research at the Center for Energy Efficient Materials (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum

    ScienceCinema

    Bowers, John (Director, Center for Energy Efficient Materials ); CEEM Staff

    2017-12-09

    'Undergraduate Research at the Center for Energy Efficient Materials (CEEM)' was submitted by CEEM to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. CEEM, an EFRC directed by John Bowers at the University of California, Santa Barbara is a partnership of scientists from four institutions: UC, Santa Barbara (lead), UC, Santa Cruz, Los Alamos National Laboratory, and National Renewable Energy Laboratory. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges. The mission of the Center for Energy Efficient Materials is 'to discover and develop materials that control the interactions between light, electricity, and heat at the nanoscale for improved solar energy conversion, solid-state lighting, and conversion of heat into electricity.' Research topics are: solar photovoltaic, photonic, solid state lighting, optics, thermoelectric, bio-inspired, electrical energy storage, batteries, battery electrodes, novel materials synthesis, and scalable processing.

  14. The UP College of Nursing Collaborating Center for Nursing Development in Primary Health Care.

    PubMed

    Yapchiongco, A S

    1990-01-01

    Officially designated as one of WHO's Collaborating Centers for Nursing Development (CCND), the UP College of Nursing in the Philippines will take on a leading role in achieving "health for all" through primary health care (PHC). The 1978 Declaration of Alma-Ata called for the goal of health for all by the year 2000, and recognized the key role of the nursing profession in this effort. In order to be designated a WHO collaborating center, an institution must be able to provide scientific and technical leadership at the national and international level, must be a stable institution, and must have the capacity to contribute to WHO programs. A WHO collaborating center forms part of an international network of institutions. Having become such a center, the UP College will form part of the Global Network for Nursing Development, organized in March 1987. The Global Network's functions include: 1) coordinating activities and promoting technical cooperation; 2) disseminating and exchanging informational; 3) monitoring trends in health services development and assessing their implications for nursing development; 4) supporting research; 5) gathering support and resources; and 6) promoting the goals of nursing development. As part of the Global Network, the UP College has developed a 4-year plan to fulfill the network's functions. During the June 1989 inauguration of the CCND, the Philippine Secretary of Health, Dr. Alfredo R. A. Bengzon, noted the country's lopsided ratio of health personnel per population, and issued a challenge to the UP College to lead the country in accelerating nursing development.

  15. Performance Theory of Diagonal Conducting Wall Magnetohydrodynamic Accelerators

    NASA Technical Reports Server (NTRS)

    Litchford, R. J.

    2004-01-01

    The theoretical performance of diagonal conducting wall crossed-field accelerators is examined on the basis of an infinite segmentation assumption using a cross-plane averaged generalized Ohm s law for a partially ionized gas, including ion slip. The desired accelerator performance relationships are derived from the cross-plane averaged Ohm s law by imposing appropriate configuration and loading constraints. A current-dependent effective voltage drop model is also incorporated to account for cold-wall boundary layer effects, including gasdynamic variations, discharge constriction, and electrode falls. Definition of dimensionless electric fields and current densities leads to the construction of graphical performance diagrams, which further illuminate the rudimentary behavior of crossed-field accelerator operation.

  16. Accelerated Adoption of Advanced Health Information Technology in Beacon Community Health Centers.

    PubMed

    Jones, Emily; Wittie, Michael

    2015-01-01

    To complement national and state-level HITECH Act programs, 17 Beacon communities were funded to fuel community-wide use of health information technology to improve quality. Health centers in Beacon communities received supplemental funding. This article explores the association between participation in the Beacon program and the adoption of electronic health records. Using the 2010-2012 Uniform Data System, trends in health information technology adoption among health centers located within and outside of Beacon communities were explored using differences in mean t tests and multivariate logistic regression. Electronic health record adoption was widespread and rapidly growing in all health centers, especially quality improvement functionalities: structured data capture, order and results management, and clinical decision support. Adoption lagged for functionalities supporting patient engagement, performance measurement, care coordination, and public health. The use of advanced functionalities such as care coordination grew faster in Beacon health centers, and Beacon health centers had 1.7 times higher odds of adopting health records with basic safety and quality functionalities in 2010-2012. Three factors likely underlie these findings: technical assistance, community-wide activation supporting health information exchange, and the layering of financial incentives. Additional technical assistance and community-wide activation is needed to support the use of functionalities that are currently lagging. © Copyright 2015 by the American Board of Family Medicine.

  17. U.S. Department of Energy's Bioenergy Research Centers An Overview of the Science

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

    None

    2010-07-01

    biofuel production, DOE established three Bioenergy Research Centers (BRCs) in September 2007. Each center is pursuing the basic research underlying a range of high-risk, high-return biological solutions for bioenergy applications. Advances resulting from the BRCs are providing the knowledge needed to develop new biobased products, methods, and tools that the emerging biofuel industry can use (see sidebar, Bridging the Gap from Fundamental Biology to Industrial Innovation for Bioenergy, p. 6). The DOE BRCs have developed automated, high-throughput analysis pipelines that will accelerate scientific discovery for biology-based biofuel research. The three centers, which were selected through a scientific peer-review process, are based in geographically diverse locations - the Southeast, the Midwest, and the West Coast - with partners across the nation (see U.S. map, DOE Bioenergy Research Centers and Partners, on back cover). DOE's Lawrence Berkeley National Laboratory leads the DOE Joint BioEnergy Institute (JBEI) in California; DOE's Oak Ridge National Laboratory leads the BioEnergy Science Center (BESC) in Tennessee; and the University of Wisconsin-Madison leads the Great Lakes Bioenergy Research Center (GLBRC). Each center represents a multidisciplinary partnership with expertise spanning the physical and biological sciences, including genomics, microbial and plant biology, analytical chemistry, computational biology and bioinformatics, and engineering. Institutional partners include DOE national laboratories, universities, private companies, and nonprofit organizations.« less

  18. Predicting Dynamic Postural Instability Using Center of Mass Time-to-Contact Information

    PubMed Central

    Hasson, Christopher J.; Van Emmerik, Richard E.A.; Caldwell, Graham E.

    2008-01-01

    Our purpose was to determine whether spatiotemporal measures of center of mass motion relative to the base of support boundary could predict stepping strategies after upper-body postural perturbations in humans. We expected that inclusion of center of mass acceleration in such time-to-contact (TtC) calculations would give better predictions and more advanced warning of perturbation severity. TtC measures were compared with traditional postural variables, which don’t consider support boundaries, and with an inverted pendulum model of dynamic stability developed by Hof et al. (2005). A pendulum was used to deliver sequentially increasing perturbations to 10 young adults, who were strapped to a wooden backboard that constrained motion to sagittal plane rotation about the ankle joint. Subjects were instructed to resist the perturbations, stepping only if necessary to prevent a fall. Peak center of mass and center of pressure velocity and acceleration demonstrated linear increases with postural challenge. In contrast, boundary relevant minimum TtC values decreased nonlinearly with postural challenge, enabling prediction of stepping responses using quadratic equations. When TtC calculations incorporated center of mass acceleration, the quadratic fits were better and gave more accurate predictions of the TtC values that would trigger stepping responses. In addition, TtC minima occurred earlier with acceleration inclusion, giving more advanced warning of perturbation severity. Our results were in agreement with TtC predictions based on Hof’s model, and suggest that TtC may function as a control parameter, influencing the postural control system’s decision to transition from a stationary base of support to a stepping strategy. PMID:18556003

  19. Energy Frontier Research Centers: Helping Win the Energy Innovation Race (2011 EFRC Summit Keynote Address, Secretary of Energy Chu)

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

    Chu, Steven

    2011-05-25

    Secretary of Energy Steven Chu gave the keynote address at the 2011 EFRC Summit and Forum. In his talk, Secretary Chu highlighted the need to "unleash America's science and research community" to achieve energy breakthroughs. The 2011 EFRC Summit and Forum brought together the EFRC community and science and policy leaders from universities, national laboratories, industry and government to discuss "Science for our Nation's Energy Future." In August 2009, the Office of Science established 46 Energy Frontier Research Centers. The EFRCs are collaborative research efforts intended to accelerate high-risk, high-reward fundamental research, the scientific basis for transformative energy technologies ofmore » the future. These Centers involve universities, national laboratories, nonprofit organizations, and for-profit firms, singly or in partnerships, selected by scientific peer review. They are funded at $2 to $5 million per year for a total planned DOE commitment of $777 million over the initial five-year award period, pending Congressional appropriations. These integrated, multi-investigator Centers are conducting fundamental research focusing on one or more of several “grand challenges” and use-inspired “basic research needs” recently identified in major strategic planning efforts by the scientific community. The purpose of the EFRCs is to integrate the talents and expertise of leading scientists in a setting designed to accelerate research that transforms the future of energy and the environment.« less

  20. Accelerated Performance Testing on the 2006 NCAT Pavement Test Track

    DOT National Transportation Integrated Search

    2009-12-01

    The original National Center for Asphalt Technology (NCAT) Pavement Test Track was built in 2000 in Opelika, Alabama where it has served as a state-of-the-art, full-scale, closed-loop accelerated loading facility. The construction, operation, and res...

  1. The Stress Acceleration Hypothesis of Nightmares

    PubMed Central

    Nielsen, Tore

    2017-01-01

    Adverse childhood experiences can deleteriously affect future physical and mental health, increasing risk for many illnesses, including psychiatric problems, sleep disorders, and, according to the present hypothesis, idiopathic nightmares. Much like post-traumatic nightmares, which are triggered by trauma and lead to recurrent emotional dreaming about the trauma, idiopathic nightmares are hypothesized to originate in early adverse experiences that lead in later life to the expression of early memories and emotions in dream content. Accordingly, the objectives of this paper are to (1) review existing literature on sleep, dreaming and nightmares in relation to early adverse experiences, drawing upon both empirical studies of dreaming and nightmares and books and chapters by recognized nightmare experts and (2) propose a new approach to explaining nightmares that is based upon the Stress Acceleration Hypothesis of mental illness. The latter stipulates that susceptibility to mental illness is increased by adversity occurring during a developmentally sensitive window for emotional maturation—the infantile amnesia period—that ends around age 3½. Early adversity accelerates the neural and behavioral maturation of emotional systems governing the expression, learning, and extinction of fear memories and may afford short-term adaptive value. But it also engenders long-term dysfunctional consequences including an increased risk for nightmares. Two mechanisms are proposed: (1) disruption of infantile amnesia allows normally forgotten early childhood memories to influence later emotions, cognitions and behavior, including the common expression of threats in nightmares; (2) alterations of normal emotion regulation processes of both waking and sleep lead to increased fear sensitivity and less effective fear extinction. These changes influence an affect network previously hypothesized to regulate fear extinction during REM sleep, disruption of which leads to nightmares. This

  2. Ion acceleration and heating by kinetic Alfvén waves associated with magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Liang, Ji; Lin, Yu; Johnson, Jay R.; Wang, Zheng-Xiong; Wang, Xueyi

    2017-10-01

    Our previous study on the generation and signatures of kinetic Alfvén waves (KAWs) associated with magnetic reconnection in a current sheet revealed that KAWs are a common feature during reconnection [Liang et al. J. Geophys. Res.: Space Phys. 121, 6526 (2016)]. In this paper, ion acceleration and heating by the KAWs generated during magnetic reconnection are investigated with a three-dimensional (3-D) hybrid model. It is found that in the outflow region, a fraction of inflow ions are accelerated by the KAWs generated in the leading bulge region of reconnection, and their parallel velocities gradually increase up to slightly super-Alfvénic. As a result of wave-particle interactions, an accelerated ion beam forms in the direction of the anti-parallel magnetic field, in addition to the core ion population, leading to the development of non-Maxwellian velocity distributions, which include a trapped population with parallel velocities consistent with the wave speed. The ions are heated in both parallel and perpendicular directions. In the parallel direction, the heating results from nonlinear Landau resonance of trapped ions. In the perpendicular direction, however, evidence of stochastic heating by the KAWs is found during the acceleration stage, with an increase of magnetic moment μ. The coherence in the perpendicular ion temperature T⊥ and the perpendicular electric and magnetic fields of KAWs also provides evidence for perpendicular heating by KAWs. The parallel and perpendicular heating of the accelerated beam occur simultaneously, leading to the development of temperature anisotropy with T⊥>T∥ . The heating rate agrees with the damping rate of the KAWs, and the heating is dominated by the accelerated ion beam. In the later stage, with the increase of the fraction of the accelerated ions, interaction between the accelerated beam and the core population also contributes to the ion heating, ultimately leading to overlap of the beams and an overall

  3. Ion acceleration and heating by kinetic Alfvén waves associated with magnetic reconnection

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

    Liang, Ji; Lin, Yu; Johnson, Jay R.

    In a previous study on the generation and signatures of kinetic Alfv en waves (KAWs) associated with magnetic reconnection in a current sheet revealed that KAWs are a common feature during reconnection [Liang et al. J. Geophys. Res.: Space Phys. 121, 6526 (2016)]. In this paper, ion acceleration and heating by the KAWs generated during magnetic reconnection are investigated with a three-dimensional (3-D) hybrid model. It is found that in the outflow region, a fraction of inflow ions are accelerated by the KAWs generated in the leading bulge region of reconnection, and their parallel velocities gradually increase up to slightly super-Alfv enic. As a result of waveparticle interactions, an accelerated ion beam forms in the direction of the anti-parallel magnetic field, in addition to the core ion population, leading to the development of non-Maxwellian velocity distributions, which include a trapped population with parallel velocities consistent with the wave speed. We then heat ions in both parallel and perpendicular directions. In the parallel direction, the heating results from nonlinear Landau resonance of trapped ions. In the perpendicular direction, however, evidence of stochastic heating by the KAWs is found during the acceleration stage, with an increase of magnetic moment μ. The coherence in the T more » $$\\perp$$ ion temperature and the perpendicular electric and magnetic fields of KAWs also provides evidence for perpendicular heating by KAWs. The parallel and perpendicular heating of the accelerated beam occur simultaneously, leading to the development of temperature anisotropy with the perpendicular temperature T $$\\perp$$>T $$\\parallel$$ temperature. The heating rate agrees with the damping rate of the KAWs, and the heating is dominated by the accelerated ion beam. In the later stage, with the increase of the fraction of the accelerated ions, interaction between the accelerated beam and the core population also contributes to the ion heating

  4. Ion acceleration and heating by kinetic Alfvén waves associated with magnetic reconnection

    DOE PAGES

    Liang, Ji; Lin, Yu; Johnson, Jay R.; ...

    2017-09-19

    In a previous study on the generation and signatures of kinetic Alfv en waves (KAWs) associated with magnetic reconnection in a current sheet revealed that KAWs are a common feature during reconnection [Liang et al. J. Geophys. Res.: Space Phys. 121, 6526 (2016)]. In this paper, ion acceleration and heating by the KAWs generated during magnetic reconnection are investigated with a three-dimensional (3-D) hybrid model. It is found that in the outflow region, a fraction of inflow ions are accelerated by the KAWs generated in the leading bulge region of reconnection, and their parallel velocities gradually increase up to slightly super-Alfv enic. As a result of waveparticle interactions, an accelerated ion beam forms in the direction of the anti-parallel magnetic field, in addition to the core ion population, leading to the development of non-Maxwellian velocity distributions, which include a trapped population with parallel velocities consistent with the wave speed. We then heat ions in both parallel and perpendicular directions. In the parallel direction, the heating results from nonlinear Landau resonance of trapped ions. In the perpendicular direction, however, evidence of stochastic heating by the KAWs is found during the acceleration stage, with an increase of magnetic moment μ. The coherence in the T more » $$\\perp$$ ion temperature and the perpendicular electric and magnetic fields of KAWs also provides evidence for perpendicular heating by KAWs. The parallel and perpendicular heating of the accelerated beam occur simultaneously, leading to the development of temperature anisotropy with the perpendicular temperature T $$\\perp$$>T $$\\parallel$$ temperature. The heating rate agrees with the damping rate of the KAWs, and the heating is dominated by the accelerated ion beam. In the later stage, with the increase of the fraction of the accelerated ions, interaction between the accelerated beam and the core population also contributes to the ion heating

  5. First results with the novel petawatt laser acceleration facility in Dresden

    NASA Astrophysics Data System (ADS)

    Schramm, U.; Bussmann, M.; Irman, A.; Siebold, M.; Zeil, K.; Albach, D.; Bernert, C.; Bock, S.; Brack, F.; Branco, J.; Couperus, JP; Cowan, TE; Debus, A.; Eisenmann, C.; Garten, M.; Gebhardt, R.; Grams, S.; Helbig, U.; Huebl, A.; Kluge, T.; Köhler, A.; Krämer, JM; Kraft, S.; Kroll, F.; Kuntzsch, M.; Lehnert, U.; Loeser, M.; Metzkes, J.; Michel, P.; Obst, L.; Pausch, R.; Rehwald, M.; Sauerbrey, R.; Schlenvoigt, HP; Steiniger, K.; Zarini, O.

    2017-07-01

    We report on first commissioning results of the DRACO Petawatt ultra-short pulse laser system implemented at the ELBE center for high power radiation sources of Helmholtz-Zentrum Dresden-Rossendorf. Key parameters of the laser system essential for efficient and reproducible performance of plasma accelerators are presented and discussed with the demonstration of 40 MeV proton acceleration under TNSA conditions as well as peaked electron spectra with unprecedented bunch charge in the 0.5 nC range.

  6. The effect of accelerated aging on the wear of UHMWPE.

    PubMed

    Sakoda, H; Fisher, J; Lu, S; Buchanan, F

    2001-01-01

    Oxidative degradation of UHMWPE has been found to be a cause of elevated wear rate of the polymer in total joint replacement leading to failure of these devices. In order to evaluate long term stability of polymers, various accelerated aging methods have been developed. In this study, wear rates of shelf aged UHMWPE and "accelerated aged" UHMWPE were compared using a multi-directional pin-on-plate wear test machine in order to evaluate the effect of the accelerated aging on wear. Wear factors of the aged materials were found to depend on their density, which is a measure of oxidation level. Finally, accelerated aging was calibrated against shelf aging in terms of wear rate. Copyright 2001 Kluwer Academic Publishers

  7. Current Fragmentation and Particle Acceleration in Solar Flares

    NASA Astrophysics Data System (ADS)

    Cargill, P. J.; Vlahos, L.; Baumann, G.; Drake, J. F.; Nordlund, Å.

    2012-11-01

    Particle acceleration in solar flares remains an outstanding problem in plasma physics and space science. While the observed particle energies and timescales can perhaps be understood in terms of acceleration at a simple current sheet or turbulence site, the vast number of accelerated particles, and the fraction of flare energy in them, defies any simple explanation. The nature of energy storage and dissipation in the global coronal magnetic field is essential for understanding flare acceleration. Scenarios where the coronal field is stressed by complex photospheric motions lead to the formation of multiple current sheets, rather than the single monolithic current sheet proposed by some. The currents sheets in turn can fragment into multiple, smaller dissipation sites. MHD, kinetic and cellular automata models are used to demonstrate this feature. Particle acceleration in this environment thus involves interaction with many distributed accelerators. A series of examples demonstrate how acceleration works in such an environment. As required, acceleration is fast, and relativistic energies are readily attained. It is also shown that accelerated particles do indeed interact with multiple acceleration sites. Test particle models also demonstrate that a large number of particles can be accelerated, with a significant fraction of the flare energy associated with them. However, in the absence of feedback, and with limited numerical resolution, these results need to be viewed with caution. Particle in cell models can incorporate feedback and in one scenario suggest that acceleration can be limited by the energetic particles reaching the condition for firehose marginal stability. Contemporary issues such as footpoint particle acceleration are also discussed. It is also noted that the idea of a "standard flare model" is ill-conceived when the entire distribution of flare energies is considered.

  8. Cavitation onset caused by acceleration

    PubMed Central

    Pan, Zhao; Kiyama, Akihito; Tagawa, Yoshiyuki; Daily, David J.; Thomson, Scott L.; Hurd, Randy

    2017-01-01

    Striking the top of a liquid-filled bottle can shatter the bottom. An intuitive interpretation of this event might label an impulsive force as the culprit in this fracturing phenomenon. However, high-speed photography reveals the formation and collapse of tiny bubbles near the bottom before fracture. This observation indicates that the damaging phenomenon of cavitation is at fault. Cavitation is well known for causing damage in various applications including pipes and ship propellers, making accurate prediction of cavitation onset vital in several industries. However, the conventional cavitation number as a function of velocity incorrectly predicts the cavitation onset caused by acceleration. This unexplained discrepancy leads to the derivation of an alternative dimensionless term from the equation of motion, predicting cavitation as a function of acceleration and fluid depth rather than velocity. Two independent research groups in different countries have tested this theory; separate series of experiments confirm that an alternative cavitation number, presented in this paper, defines the universal criteria for the onset of acceleration-induced cavitation. PMID:28739956

  9. Cavitation onset caused by acceleration.

    PubMed

    Pan, Zhao; Kiyama, Akihito; Tagawa, Yoshiyuki; Daily, David J; Thomson, Scott L; Hurd, Randy; Truscott, Tadd T

    2017-07-24

    Striking the top of a liquid-filled bottle can shatter the bottom. An intuitive interpretation of this event might label an impulsive force as the culprit in this fracturing phenomenon. However, high-speed photography reveals the formation and collapse of tiny bubbles near the bottom before fracture. This observation indicates that the damaging phenomenon of cavitation is at fault. Cavitation is well known for causing damage in various applications including pipes and ship propellers, making accurate prediction of cavitation onset vital in several industries. However, the conventional cavitation number as a function of velocity incorrectly predicts the cavitation onset caused by acceleration. This unexplained discrepancy leads to the derivation of an alternative dimensionless term from the equation of motion, predicting cavitation as a function of acceleration and fluid depth rather than velocity. Two independent research groups in different countries have tested this theory; separate series of experiments confirm that an alternative cavitation number, presented in this paper, defines the universal criteria for the onset of acceleration-induced cavitation.

  10. Cavitation onset caused by acceleration

    NASA Astrophysics Data System (ADS)

    Pan, Zhao; Kiyama, Akihito; Tagawa, Yoshiyuki; Daily, David J.; Thomson, Scott L.; Hurd, Randy; Truscott, Tadd T.

    2017-08-01

    Striking the top of a liquid-filled bottle can shatter the bottom. An intuitive interpretation of this event might label an impulsive force as the culprit in this fracturing phenomenon. However, high-speed photography reveals the formation and collapse of tiny bubbles near the bottom before fracture. This observation indicates that the damaging phenomenon of cavitation is at fault. Cavitation is well known for causing damage in various applications including pipes and ship propellers, making accurate prediction of cavitation onset vital in several industries. However, the conventional cavitation number as a function of velocity incorrectly predicts the cavitation onset caused by acceleration. This unexplained discrepancy leads to the derivation of an alternative dimensionless term from the equation of motion, predicting cavitation as a function of acceleration and fluid depth rather than velocity. Two independent research groups in different countries have tested this theory; separate series of experiments confirm that an alternative cavitation number, presented in this paper, defines the universal criteria for the onset of acceleration-induced cavitation.

  11. TAC Proton Accelerator Facility: The Status and Road Map

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

    Algin, E.; Akkus, B.; Caliskan, A.

    2011-06-28

    Proton Accelerator (PA) Project is at a stage of development, working towards a Technical Design Report under the roof of a larger-scale Turkish Accelerator Center (TAC) Project. The project is supported by the Turkish State Planning Organization. The PA facility will be constructed in a series of stages including a 3 MeV test stand, a 55 MeV linac which can be extended to 100+ MeV, and then a full 1-3 GeV proton synchrotron or superconducting linac. In this article, science applications, overview, and current status of the PA Project will be given.

  12. A Generalized Equatorial Model for the Accelerating Solar Wind

    NASA Astrophysics Data System (ADS)

    Tasnim, S.; Cairns, Iver H.; Wheatland, M. S.

    2018-02-01

    A new theoretical model for the solar wind is developed that includes the wind's acceleration, conservation of angular momentum, deviations from corotation, and nonradial velocity and magnetic field components from an inner boundary (corresponding to the onset of the solar wind) to beyond 1 AU. The model uses a solution of the time-steady isothermal equation of motion to describe the acceleration and analytically predicts the Alfvénic critical radius. We fit the model to near-Earth observations of the Wind spacecraft during the solar rotation period of 1-27 August 2010. The resulting data-driven model demonstrates the existence of noncorotating, nonradial flows and fields from the inner boundary (r = rs) outward and predicts the magnetic field B = (Br,Bϕ), velocity v = (vr,vϕ), and density n(r,ϕ,t), which vary with heliocentric distance r, heliolatitude ϕ, and time t in a Sun-centered standard inertial plane. The description applies formally only in the equatorial plane. In a frame corotating with the Sun, the transformed velocity v' and a field B' are not parallel, resulting in an electric field with a component Ez' along the z axis. The resulting E'×B'=E'×B drift lies in the equatorial plane, while the ∇B and curvature drifts are out of the plane. Together these may lead to enhanced scattering/heating of sufficiently energetic particles. The model predicts that deviations δvϕ from corotation at the inner boundary are common, with δvϕ(rs,ϕs,ts) comparable to the transverse velocities due to granulation and supergranulation motions. Abrupt changes in δvϕ(rs,ϕs,ts) are interpreted in terms of converging and diverging flows at the cell boundaries and centers, respectively. Large-scale variations in the predicted angular momentum demonstrate that the solar wind can drive vorticity and turbulence from near the Sun to 1 AU and beyond.

  13. Johnson Space Center

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The Johnson Space Center (JSC) in Houston is NASA's lead center for the space shuttle and the International Space Station programs and for biomedical research. Areas of study include Earth sciences and solar system exploration, astromaterials and space medicine. About 14 000 people, including 3000 civil servants, work at JSC....

  14. Solar Cells from Plastics? Mission Possible at the PHaSE Energy Research Center, UMass Amherst (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema

    Russell, Thomas P; Lahti, Paul M. (PHaSE - Polymer-Based Materials for Harvesting Solar Energy); PHaSE Staff

    2017-12-09

    'Solar Cells from Plastics? Mission Possible at the PHaSE Energy Research Center, UMass Amherst' was submitted by the Polymer-Based Materials for Harvesting Solar Energy (PHaSE) EFRC to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. PHaSE, an EFRC co-directed by Thomas P. Russell and Paul M. Lahti at the University of Massachusetts, Amherst, is a partnership of scientists from six institutions: UMass (lead), Oak Ridge National Laboratory, Pennyslvania State University, Rensselaer Polytechnic Institute, and the University of Pittsburgh. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.

  15. Solar Cells from Plastics? Mission Possible at the PHaSE Energy Research Center, UMass Amherst (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

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

    Pentzer, Emily

    "Solar Cells from Plastics? Mission Possible at the PHaSE Energy Research Center, UMass Amherst" was submitted by the Polymer-Based Materials for Harvesting Solar Energy (PHaSE) EFRC to the "Life at the Frontiers of Energy Research" video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. PHaSE, an EFRC co-directed by Thomas P. Russell and Paul M. Lahti at the University of Massachusetts, Amherst, is a partnership of scientists from six institutions: UMass (lead), Oak Ridge National Laboratory, Pennsylvania Statemore » University, Rensselaer Polytechnic Institute, and the University of Pittsburgh. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.« less

  16. A systematic FPGA acceleration design for applications based on convolutional neural networks

    NASA Astrophysics Data System (ADS)

    Dong, Hao; Jiang, Li; Li, Tianjian; Liang, Xiaoyao

    2018-04-01

    Most FPGA accelerators for convolutional neural network are designed to optimize the inner acceleration and are ignored of the optimization for the data path between the inner accelerator and the outer system. This could lead to poor performance in applications like real time video object detection. We propose a brand new systematic FPFA acceleration design to solve this problem. This design takes the data path optimization between the inner accelerator and the outer system into consideration and optimizes the data path using techniques like hardware format transformation, frame compression. It also takes fixed-point, new pipeline technique to optimize the inner accelerator. All these make the final system's performance very good, reaching about 10 times the performance comparing with the original system.

  17. KENNEDY SPACE CENTER, FLA. - At the rollout of the One NASA initiative at KSC, Glenn Research Center Director Dr. Julian Earls embraces implementation team lead Johnny Stevenson while KSC Director Jim Kennedy (left) applauds. Earls gave a motivational speech during the luncheon held at the Visitor Complex Debus Conference Center. The event was held at the IMAX Theater® where NASA leaders discussed One NASA with selected employees. Explaining how their respective centers contribute to One NASA, along with Kennedy and Earls, were James Jennings, NASA’s associate deputy administrator for institutions and asset management; Ed Weiler, associate administrator for Space Science; Kevin Peterson, Dryden Flight Research Center director; incoming KSC Deputy Director Woodrow Whitlow; and implementation team lead Johnny Stevenson.

    NASA Image and Video Library

    2003-08-20

    KENNEDY SPACE CENTER, FLA. - At the rollout of the One NASA initiative at KSC, Glenn Research Center Director Dr. Julian Earls embraces implementation team lead Johnny Stevenson while KSC Director Jim Kennedy (left) applauds. Earls gave a motivational speech during the luncheon held at the Visitor Complex Debus Conference Center. The event was held at the IMAX Theater® where NASA leaders discussed One NASA with selected employees. Explaining how their respective centers contribute to One NASA, along with Kennedy and Earls, were James Jennings, NASA’s associate deputy administrator for institutions and asset management; Ed Weiler, associate administrator for Space Science; Kevin Peterson, Dryden Flight Research Center director; incoming KSC Deputy Director Woodrow Whitlow; and implementation team lead Johnny Stevenson.

  18. Generation of X-rays by electrons recycling through thin internal targets of cyclic accelerators

    NASA Astrophysics Data System (ADS)

    Kaplin, V.; Kuznetsov, S.; Uglov, S.

    2018-05-01

    The use of thin (< 10‑3 radiation length) internal targets in cyclic accelerators leads to multiple passes (recycling effect) of electrons through them. The multiplicity of electron passes (M) is determined by the electron energy, accelerator parameters, the thickness, structure and material of a target and leads to an increase in the effective target thickness and the efficiency of radiation generation. The increase of M leads to the increase in the emittance of electron beams which can change the characteristics of radiation processes. The experimental results obtained using the Tomsk synchrotron and betatron showed the possibility of increasing the yield and brightness of coherent X-rays generated by the electrons passing (recycling) through thin crystals and periodic multilayers placed into the chambers of accelerators, when the recycling effect did not influence on the spectral and angular characteristics of generated X-rays.

  19. Ultra-Accelerated Natural Sunlight Exposure Testing Facilities

    DOEpatents

    Lewandowski, Allan A.; Jorgensen, Gary J.

    2004-11-23

    A multi-faceted concentrator apparatus for providing ultra-accelerated natural sunlight exposure testing for sample materials under controlled weathering conditions comprising: facets that receive incident natural sunlight, transmits VIS/NIR and reflects UV/VIS onto a secondary reflector that delivers a uniform flux of UV/VIS onto a sample exposure plane located near a center of a facet array in a chamber that provide concurrent levels of temperature and/or relative humidity at high levels of up to 100.times. of natural sunlight that allow sample materials to be subjected to accelerated irradiance exposure factors for a significant period of time of about 3 to 10 days to provide a corresponding time of about at least a years worth representative weathering of sample materials.

  20. Ultra-accelerated natural sunlight exposure testing facilities

    DOEpatents

    Lewandowski, Allan A.; Jorgensen, Gary J.

    2003-08-12

    A multi-faceted concentrator apparatus for providing ultra-accelerated natural sunlight exposure testing for sample materials under controlled weathering conditions comprising: facets that receive incident natural sunlight, transmits VIS/NIR and reflects UV/VIS to deliver a uniform flux of UV/VIS onto a sample exposure plane located near a center of a facet array in chamber means that provide concurrent levels of temperature and/or relative humidity at high levels of up to 100.times. of natural sunlight that allow sample materials to be subjected to accelerated irradiance exposure factors for a significant period of time of about 3 to 10 days to provide a corresponding time of about at least a years worth representative weathering of sample materials.

  1. Modeling target normal sheath acceleration using handoffs between multiple simulations

    NASA Astrophysics Data System (ADS)

    McMahon, Matthew; Willis, Christopher; Mitchell, Robert; King, Frank; Schumacher, Douglass; Akli, Kramer; Freeman, Richard

    2013-10-01

    We present a technique to model the target normal sheath acceleration (TNSA) process using full-scale LSP PIC simulations. The technique allows for a realistic laser, full size target and pre-plasma, and sufficient propagation length for the accelerated ions and electrons. A first simulation using a 2D Cartesian grid models the laser-plasma interaction (LPI) self-consistently and includes field ionization. Electrons accelerated by the laser are imported into a second simulation using a 2D cylindrical grid optimized for the initial TNSA process and incorporating an equation of state. Finally, all of the particles are imported to a third simulation optimized for the propagation of the accelerated ions and utilizing a static field solver for initialization. We also show use of 3D LPI simulations. Simulation results are compared to recent ion acceleration experiments using SCARLET laser at The Ohio State University. This work was performed with support from ASOFR under contract # FA9550-12-1-0341, DARPA, and allocations of computing time from the Ohio Supercomputing Center.

  2. Case reports of lead poisoning in dogs from the National Animal Poison Control Center and the Centre National D'Informations Toxicologiques, Veterinaires: anecdotes or reality?

    PubMed

    Berny, P J; Cote, L M; Buck, W B

    1992-02-01

    This paper presents case reports of lead toxicoses from 2 major animal poison control centers in Europe and North America, gathered from 1985 through 1989. All results examined here involved cases assessed as "toxicosis" or "suspected toxicosis" by the National Animal Poison Control Center (NAPCC) or the Centre National d'Informations Toxicologiques Veterinaries (CNITV). 537 cases were reported to the NAPCC, most of them concerning dogs (59%). In France, most of the 362 cases involved cattle (57.2%). There was an increased number of cases reported during late summer and early fall, and a decreased number of cases in November and December, in both centers. Dogs intoxicated were predominantly young animals (60% were less than 2 years old). No sex difference was noted. Pure bred dogs appeared more often involved than mixed-breed ones, but the breed distribution closely resembles dog breed distribution in the US. The source of lead was usually unknown and, when information was available, paint seemed to be the most common cause of poisoning. Clinical signs reported to the animal poison control centers involved the CNS and GI tract. Results from the French and the American database showed similar trends. They are compared to data from veterinary clinics and veterinary colleges in the US and Australia. In each case, data are very similar to what was reported to the CNITV and the NAPCC. It is concluded that animal poison control centers databases can provide a useful tool for better knowledge of animal poisoning. They can also help identify unexpected toxicologic problems related to drug administration or pesticide use.

  3. Industrialization of Superconducting RF Accelerator Technology

    NASA Astrophysics Data System (ADS)

    Peiniger, Michael; Pekeler, Michael; Vogel, Hanspeter

    2012-01-01

    Superconducting RF (SRF) accelerator technology has basically existed for 50 years. It took about 20 years to conduct basic R&D and prototyping at universities and international institutes before the first superconducting accelerators were built, with industry supplying complete accelerator cavities. In parallel, the design of large scale accelerators using SRF was done worldwide. In order to build those accelerators, industry has been involved for 30 years in building the required cavities and/or accelerator modules in time and budget. To enable industry to supply these high tech components, technology transfer was made from the laboratories in the following three regions: the Americas, Asia and Europe. As will be shown, the manufacture of the SRF cavities is normally accomplished in industry whereas the cavity testing and module assembly are not performed in industry in most cases, yet. The story of industrialization is so far a story of customized projects. Therefore a real SRF accelerator product is not yet available in this market. License agreements and technology transfer between leading SRF laboratories and industry is a powerful tool for enabling industry to manufacture SRF components or turnkey superconducting accelerator modules for other laboratories and users with few or no capabilities in SRF technology. Despite all this, the SRF accelerator market today is still a small market. The manufacture and preparation of the components require a range of specialized knowledge, as well as complex and expensive manufacturing installations like for high precision machining, electron beam welding, chemical surface preparation and class ISO4 clean room assembly. Today, the involved industry in the US and Europe comprises medium-sized companies. In Japan, some big enterprises are involved. So far, roughly 2500 SRF cavities have been built by or ordered from industry worldwide. Another substantial step might come from the International Linear Collider (ILC) project

  4. Design of a ram accelerator mass launch system

    NASA Technical Reports Server (NTRS)

    Aarnio, Michael; Armerding, Calvin; Berschauer, Andrew; Christofferson, Erik; Clement, Paul; Gohd, Robin; Neely, Bret; Reed, David; Rodriguez, Carlos; Swanstrom, Fredrick

    1988-01-01

    The ram accelerator mass launch system has been proposed to greatly reduce the costs of placing acceleration-insensitive payloads into low earth orbit. The ram accelerator is a chemically propelled, impulsive mass launch system capable of efficiently accelerating relatively large masses from velocities of 0.7 km/sec to 10 km/sec. The principles of propulsion are based on those of a conventional supersonic air-breathing ramjet; however the device operates in a somewhat different manner. The payload carrying vehicle resembles the center-body of the ramjet and accelerates through a stationary tube which acts as the outer cowling. The tube is filled with premixed gaseous fuel and oxidizer mixtures that burn in the vicinity of the vehicle's base, producing a thrust which accelerates the vehicle through the tube. This study examines the requirement for placing a 2000 kg vehicle into a 500 km circular orbit with a minimum amount of on-board rocket propellant for orbital maneuvers. The goal is to achieve a 50 pct payload mass fraction. The proposed design requirements have several self-imposed constraints that define the vehicle and tube configurations. Structural considerations on the vehicle and tube wall dictate an upper acceleration limit of 1000 g's and a tube inside diameter of 1.0 m. In-tube propulsive requirements and vehicle structural constraints result in a vehicle diameter of 0.76 m, a total length of 7.5 m and a nose-cone half angle of 7 degrees. An ablating nose-cone constructed from carbon-carbon composite serves as the thermal protection mechanism for atmospheric transit.

  5. Measuring and Validating Neutron Capture Cross Sections Using a Lead Slowing-Down Spectrometer

    NASA Astrophysics Data System (ADS)

    Thompson, Nicholas

    Accurate nuclear data is essential for the modeling, design, and operation of nuclear systems. In this work, the Rensselaer Polytechnic Institute (RPI) Lead Slowing-Down Spectrometer (LSDS) at the Gaerttner Linear Accelerator Center (LINAC) was used to measure neutron capture cross sections and validate capture cross sections in cross section libraries. The RPI LINAC was used to create a fast burst of neutrons in the center of the LSDS, a large cube of high purity lead. A sample and YAP:Ce scintillator were placed in the LSDS, and as neutrons lost energy through scattering interactions with the lead, the scintillator detected capture gammas resulting from neutron capture events in the sample. Samples of silver, gold, cobalt, iron, indium, molybdenum, niobium, nickel, tin, tantalum, and zirconium were measured. Data was collected as a function of time after neutron pulse, or slowing-down time, which is correlated to average neutron energy. An analog and a digital data acquisition system collected data simultaneously, allowing for collection of pulse shape information as well as timing. Collection of digital data allowed for pulse shape analysis after the experiment. This data was then analyzed and compared to Monte Carlo simulations to validate the accuracy of neutron capture cross section libraries. These measurements represent the first time that neutron capture cross sections have been measured using an LSDS in the United States, and the first time tools such as coincidence measurements and pulse height weighting have been applied to measurements of neutron capture cross sections using an LSDS. Significant differences between measurement results and simulation results were found in multiple materials, and some errors in nuclear data libraries have already been identified due to these measurements.

  6. Biological and medical research with accelerated heavy ions at the Bevalac, 1977-1980. [Lead abstract

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

    Pirruccello, M.C.; Tobias, C.A.

    1980-11-01

    Separate abstracts were prepared for the 46 papers presented in this progress report. This report is a major review of studies with accelerated heavy ions carried out by the Biology and Medicine Division of Lawrence Berkeley Laboratory from 1977 to 1980. (KRM)

  7. Reduced 3d modeling on injection schemes for laser wakefield acceleration at plasma scale lengths

    NASA Astrophysics Data System (ADS)

    Helm, Anton; Vieira, Jorge; Silva, Luis; Fonseca, Ricardo

    2017-10-01

    Current modelling techniques for laser wakefield acceleration (LWFA) are based on particle-in-cell (PIC) codes which are computationally demanding. In PIC simulations the laser wavelength λ0, in μm-range, has to be resolved over the acceleration lengths in meter-range. A promising approach is the ponderomotive guiding center solver (PGC) by only considering the laser envelope for laser pulse propagation. Therefore only the plasma skin depth λp has to be resolved, leading to speedups of (λp /λ0) 2. This allows to perform a wide-range of parameter studies and use it for λ0 <<λp studies. We present the 3d version of a PGC solver in the massively parallel, fully relativistic PIC code OSIRIS. Further, a discussion and characterization of the validity of the PGC solver for injection schemes on the plasma scale lengths, such as down-ramp injection, magnetic injection and ionization injection, through parametric studies, full PIC simulations and theoretical scaling, is presented. This work was partially supported by Fundacao para a Ciencia e Tecnologia (FCT), Portugal, through Grant No. PTDC/FIS-PLA/2940/2014 and PD/BD/105882/2014.

  8. The center for production of single-photon emitters at the electrostatic-deflector line of the Tandem accelerator of LABEC (Florence)

    NASA Astrophysics Data System (ADS)

    Lagomarsino, Stefano; Sciortino, Silvio; Gelli, Nicla; Flatae, Assegid M.; Gorelli, Federico; Santoro, Mario; Chiari, Massimo; Czelusniac, Caroline; Massi, Mirko; Taccetti, Francesco; Agio, Mario; Giuntini, Lorenzo

    2018-05-01

    The line for the pulsed beam of the 3 MeV Tandetron accelerator at LABEC (Florence) has been upgraded for ion implantation experiments aiming at the fabrication of single-photon emitters in a solid-state matrix. A system based on Al attenuators has been calibrated in order to extend the energy range of the implanted ions from MeV down to the tens of keV. A new motorized XY stage has been installed in the implantation chamber for achieving ultra-fine control on the position of each implanted ion, allowing to reach the scale imposed by lateral straggling. A set-up for the activation of the implanted ions has been developed, based on an annealing furnace operating under controlled high-vacuum conditions. The first experiments have been performed with silicon ions implanted in diamond and the luminescent signal of the silicon-vacancy (SiV) center, peaked at 738 nm, has been observed for a wide range of implantation fluences (108 ÷ 1015 cm-2) and implantation depths (from a few nm to 2.4 μm). Studies on the efficiency of the annealing process have been performed and the activation yield has been measured to range from 1% to 3%. The implantation and annealing facility has thus been tuned for the production of SiV centers in diamond, but is in principle suitable for other ion species and solid-state matrices.

  9. Fluid Physics Under a Stochastic Acceleration Field

    NASA Technical Reports Server (NTRS)

    Vinals, Jorge

    2001-01-01

    The research summarized in this report has involved a combined theoretical and computational study of fluid flow that results from the random acceleration environment present onboard space orbiters, also known as g-jitter. We have focused on a statistical description of the observed g-jitter, on the flows that such an acceleration field can induce in a number of experimental configurations of interest, and on extending previously developed methodology to boundary layer flows. Narrow band noise has been shown to describe many of the features of acceleration data collected during space missions. The scale of baroclinically induced flows when the driving acceleration is random is not given by the Rayleigh number. Spatially uniform g-jitter induces additional hydrodynamic forces among suspended particles in incompressible fluids. Stochastic modulation of the control parameter shifts the location of the onset of an oscillatory instability. Random vibration of solid boundaries leads to separation of boundary layers. Steady streaming ahead of a modulated solid-melt interface enhances solute transport, and modifies the stability boundaries of a planar front.

  10. Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.

    PubMed

    Braenzel, J; Andreev, A A; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M

    2015-03-27

    An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19}  W/  cm^{2}. Highly charged gold ions with kinetic energies up to >200  MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.

  11. Designing a Dielectric Laser Accelerator on a Chip

    NASA Astrophysics Data System (ADS)

    Niedermayer, Uwe; Boine-Frankenheim, Oliver; Egenolf, Thilo

    2017-07-01

    Dielectric Laser Acceleration (DLA) achieves gradients of more than 1GeV/m, which are among the highest in non-plasma accelerators. The long-term goal of the ACHIP collaboration is to provide relativistic (>1 MeV) electrons by means of a laser driven microchip accelerator. Examples of ’’slightly resonant” dielectric structures showing gradients in the range of 70% of the incident laser field (1 GV/m) for electrons with beta=0.32 and 200% for beta=0.91 are presented. We demonstrate the bunching and acceleration of low energy electrons in dedicated ballistic buncher and velocity matched grating structures. However, the design gradient of 500 MeV/m leads to rapid defocusing. Therefore we present a scheme to bunch the beam in stages, which does not only reduce the energy spread, but also the transverse defocusing. The designs are made with a dedicated homemade 6D particle tracking code.

  12. Observations of the Coronal Mass Ejection with a Complex Acceleration Profile

    NASA Astrophysics Data System (ADS)

    Reva, A. A.; Kirichenko, A. S.; Ulyanov, A. S.; Kuzin, S. V.

    2017-12-01

    We study the coronal mass ejection (CME) with a complex acceleration profile. The event occurred on 2009 April 23. It had an impulsive acceleration phase, an impulsive deceleration phase, and a second impulsive acceleration phase. During its evolution, the CME showed signatures of different acceleration mechanisms: kink instability, prominence drainage, flare reconnection, and a CME–CME collision. The special feature of the observations is the usage of the TESIS EUV telescope. The instrument could image the solar corona in the Fe 171 Å line up to a distance of 2 {R}ȯ from the center of the Sun. This allows us to trace the CME up to the LASCO/C2 field of view without losing the CME from sight. The onset of the CME was caused by kink instability. The mass drainage occurred after the kink instability. The mass drainage played only an auxiliary role: it decreased the CME mass, which helped to accelerate the CME. The first impulsive acceleration phase was caused by the flare reconnection. We observed the two-ribbon flare and an increase of the soft X-ray flux during the first impulsive acceleration phase. The impulsive deceleration and the second impulsive acceleration phases were caused by the CME–CME collision. The studied event shows that CMEs are complex phenomena that cannot be explained with only one acceleration mechanism. We should seek a combination of different mechanisms that accelerate CMEs at different stages of their evolution.

  13. Undergraduate Research at the Center for Energy Efficient Materials (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum

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

    Halabi, Linda

    "Undergraduate Research at the Center for Energy Efficient Materials (CEEM)" was submitted by CEEM to the "Life at the Frontiers of Energy Research" video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. CEEM, an EFRC directed by John Bowers at the University of California, Santa Barbara is a partnership of scientists from four institutions: UC, Santa Barbara (lead), UC, Santa Cruz, Los Alamos National Laboratory, and National Renewable Energy Laboratory. The Office of Basic Energy Sciences in themore » U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges. The mission of the Center for Energy Efficient Materials is 'to discover and develop materials that control the interactions between light, electricity, and heat at the nanoscale for improved solar energy conversion, solid-state lighting, and conversion of heat into electricity.' Research topics are: solar photovoltaic, photonic, solid state lighting, optics, thermoelectric, bio-inspired, electrical energy storage, batteries, battery electrodes, novel materials synthesis, and scalable processing.« less

  14. Choice reaction time to movement of eccentric visual targets during concurrent rotary acceleration

    NASA Technical Reports Server (NTRS)

    Hamerman, J. A.

    1979-01-01

    This study investigates the influence of concurrent rotary acceleration on choice reaction time (RT) to a small, accelerating visual cursor on a cathode-ray tube. Subjects sat in an enclosed rotating device at the center of rotation and observed a 3-mm dot accelerating at different rates across a cathode-ray tube. The dot was viewed at various eccentricities under conditions of visual stimulation alone and with concurrent rotary acceleration. Subjects responded to both vertical and horizontal dot movements. There was a significant inverse relationship between choice RT and level of dot acceleration (p less than .001), and a significant direct relationship between choice RT and eccentricity (p less than .001). There was no significant difference between choice RT to vertical or horizontal dot motion (p greater than .25), and choice RT was not significantly affected by concurrent rotary acceleration (p greater than .10). The results are discussed in terms of the effects of vestibular stimulation on choice RT to visual motion.

  15. Development of a 20 MeV Dielectric-Loaded Test Accelerator

    NASA Astrophysics Data System (ADS)

    Gold, Steven H.; Kinkead, Allen K.; Gai, Wei; Power, John G.; Konecny, Richard; Jing, Chunguang; Long, Jidong; Tantawi, Sami G.; Nantista, Christopher D.; Bruce, Ralph W.; Fliflet, Arne W.; Lombardi, Marcie; Lewis, David

    2006-11-01

    This paper presents a progress report on a joint project by the Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), to develop a dielectric-loaded test accelerator in the magnicon facility at NRL. The accelerator will be powered by an experimental 11.424-GHz magnicon amplifier that presently produces 25 MW of output power in a ˜250-ns pulse at up to 10 Hz. The accelerator will include a 5-MeV electron injector originally developed at the Tsinghua University in Beijing, China, and can incorporate DLA structures up to 0.5 m in length. The DLA structures are being developed by ANL, and shorter test structures fabricated from a variety of dielectric materials have undergone testing at NRL at gradients up to ˜8 MV/m. SLAC has developed components to distribute the power from the two magnicon output arms to the injector and to the DLA accelerating structure with separate control of the power ratio and relative phase. RWBruce Associates, Inc., working with NRL, has investigated means to join short ceramic sections into a continuous accelerator tube by a brazing process using an intense 83-GHz beam. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA test structure, and spectrometer, should take place within the next year.

  16. Similar muscles contribute to horizontal and vertical acceleration of center of mass in forward and backward walking: implications for neural control

    PubMed Central

    Jansen, Karen; De Groote, Friedl; Massaad, Firas; Meyns, Pieter; Jonkers, Ilse

    2012-01-01

    Leg kinematics during backward walking (BW) are very similar to the time-reversed kinematics during forward walking (FW). This suggests that the underlying muscle activation pattern could originate from a simple time reversal, as well. Experimental electromyography studies have confirmed that this is the case for some muscles. Furthermore, it has been hypothesized that muscles showing a time reversal should also exhibit a reversal in function [from accelerating the body center of mass (COM) to decelerating]. However, this has not yet been verified in simulation studies. In the present study, forward simulations were used to study the effects of muscles on the acceleration of COM in FW and BW. We found that a reversal in function was indeed present in the muscle control of the horizontal movement of COM (e.g., tibialis anterior and gastrocnemius). In contrast, muscles' antigravity contributions maintained their function for both directions of movement. An important outcome of the present study is therefore that similar muscles can be used to achieve opposite functional demands at the level of control of the COM when walking direction is reversed. However, some muscles showed direction-specific contributions (i.e., dorsiflexors). We concluded that the changes in muscle contributions imply that a simple time reversal would be insufficient to produce BW from FW. We therefore propose that BW utilizes extra elements, presumably supraspinal, in addition to a common spinal drive. These additions are needed for propulsion and require a partial reconfiguration of lower level common networks. PMID:22423005

  17. Essay: Robert H. Siemann As Leader of the Advanced Accelerator Research Department

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

    Colby, Eric R.; Hogan, Mark J.; /SLAC

    Robert H. Siemann originally conceived of the Advanced Accelerator Research Department (AARD) as an academic, experimental group dedicated to probing the technical limitations of accelerators while providing excellent educational opportunities for young scientists. The early years of the Accelerator Research Department B, as it was then known, were dedicated to a wealth of mostly student-led experiments to examine the promise of advanced accelerator techniques. High-gradient techniques including millimeter-wave rf acceleration, beam-driven plasma acceleration, and direct laser acceleration were pursued, including tests of materials under rf pulsed heating and short-pulse laser radiation, to establish the ultimate limitations on gradient. As themore » department and program grew, so did the motivation to found an accelerator research center that brought experimentalists together in a test facility environment to conduct a broad range of experiments. The Final Focus Test Beam and later the Next Linear Collider Test Accelerator provided unique experimental facilities for AARD staff and collaborators to carry out advanced accelerator experiments. Throughout the evolution of this dynamic program, Bob maintained a department atmosphere and culture more reminiscent of a university research group than a national laboratory department. His exceptional ability to balance multiple roles as scientist, professor, and administrator enabled the creation and preservation of an environment that fostered technical innovation and scholarship.« less

  18. Accelerated laboratory weathering of acrylic lens materials

    NASA Astrophysics Data System (ADS)

    Arndt, Thomas; Richter, Steffen; Kogler, René; Pasierb, Mike; Walby, Christopher

    2015-09-01

    Flat samples from various poly(methyl methacrylate) (PMMA) formulations were subjected to outdoor weathering in Arizona and Florida, EMMAQUA® accelerated outdoor weathering, and two accelerated laboratory weathering procedures at 3 Sun irradiance which, imitate dry (Arizona) and wet (Florida) conditions. The main mode of degradation is yellowing and not the generation of haze for any weathering procedure within the investigated radiant exposure. Higher UV absorber concentrations lead to smaller changes in optical properties and in the resulting relative concentrator photovoltaic (CPV) module efficiencies. Comparison of sample properties after various weathering procedures reveals that the influence of weathering factors other than radiant exposure depends on the sample as well.

  19. Accelerated stress testing of terrestrial solar cells

    NASA Technical Reports Server (NTRS)

    Lathrop, J. W.; Hawkins, D. C.; Prince, J. L.; Walker, H. A.

    1982-01-01

    The development of an accelerated test schedule for terrestrial solar cells is described. This schedule, based on anticipated failure modes deduced from a consideration of IC failure mechanisms, involves bias-temperature testing, humidity testing (including both 85-85 and pressure cooker stress), and thermal-cycle thermal-shock testing. Results are described for 12 different unencapsulated cell types. Both gradual electrical degradation and sudden catastrophic mechanical change were observed. These effects can be used to discriminate between cell types and technologies relative to their reliability attributes. Consideration is given to identifying laboratory failure modes which might lead to severe degradation in the field through second quadrant operation. Test results indicate that the ability of most cell types to withstand accelerated stress testing depends more on the manufacturer's design, processing, and worksmanship than on the particular metallization system. Preliminary tests comparing accelerated test results on encapsulated and unencapsulated cells are described.

  20. An introduction to the physics of high energy accelerators

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

    Edwards, D.A.; Syphers, J.J.

    1993-01-01

    This book is an outgrowth of a course given by the authors at various universities and particle accelerator schools. It starts from the basic physics principles governing particle motion inside an accelerator, and leads to a full description of the complicated phenomena and analytical tools encountered in the design and operation of a working accelerator. The book covers acceleration and longitudinal beam dynamics, transverse motion and nonlinear perturbations, intensity dependent effects, emittance preservation methods and synchrotron radiation. These subjects encompass the core concerns of a high energy synchrotron. The authors apparently do not assume the reader has much previous knowledgemore » about accelerator physics. Hence, they take great care to introduce the physical phenomena encountered and the concepts used to describe them. The mathematical formulae and derivations are deliberately kept at a level suitable for beginners. After mastering this course, any interested reader will not find it difficult to follow subjects of more current interests. Useful homework problems are provided at the end of each chapter. Many of the problems are based on actual activities associated with the design and operation of existing accelerators.« less

  1. U.S, Department of Energy's Bioenergy Research Centers An Overview of the Science

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

    None

    2009-07-01

    program is bringing together scientists in diverse fields to understand the complex biology underlying solutions to DOE missions in energy production, environmental remediation, and climate change science. New interdisciplinary research communities are emerging, as are knowledgebases and scientific and computational resources critical to advancing large-scale, genome-based biology. To focus the most advanced biotechnology-based resources on the biological challenges of biofuel production, DOE established three Bioenergy Research Centers (BRCs) in September 2007. Each center is pursuing the basic research underlying a range of high-risk, high-return biological solutions for bioenergy applications. Advances resulting from the BRCs will provide the knowledge needed to develop new biobased products, methods, and tools that the emerging biofuel industry can use. The scientific rationale for these centers and for other fundamental genomic research critical to the biofuel industry was established at a DOE workshop involving members of the research community (see sidebar, Biofuel Research Plan, below). The DOE BRCs have developed automated, high-throughput analysis pipelines that will accelerate scientific discovery for biology-based biofuel research. The three centers, which were selected through a scientific peer-review process, are based in geographically diverse locations--the Southeast, the Midwest, and the West Coast--with partners across the nation. DOE's Oak Ridge National Laboratory leads the BioEnergy Science Center (BESC) in Tennessee; the University of Wisconsin-Madison leads the Great Lakes Bioenergy Research Center (GLBRC); and DOE's Lawrence Berkeley National Laboratory leads the DOE Joint BioEnergy Institute (JBEI) in California. Each center represents a multidisciplinary partnership with expertise spanning the physical and biological sciences, including genomics, microbial and plant biology, analytical chemistry, computational biology and bioinformatics, and

  2. Experiment to Detect Accelerating Modes in a Photonic Bandgap Fiber

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

    England, R.J.; /SLAC; Colby, E.R.

    An experimental effort is currently underway at the E-163 test beamline at Stanford Linear Accelerator Center to use a hollow-core photonic bandgap (PBG) fiber as a high-gradient laser-based accelerating structure for electron bunches. For the initial stage of this experiment, a 50pC, 60 MeV electron beam will be coupled into the fiber core and the excited modes will be detected using a spectrograph to resolve their frequency signatures in the wakefield radiation generated by the beam. They will describe the experimental plan and recent simulation studies of candidate fibers.

  3. Accelerated epigenetic aging in Werner syndrome.

    PubMed

    Maierhofer, Anna; Flunkert, Julia; Oshima, Junko; Martin, George M; Haaf, Thomas; Horvath, Steve

    2017-04-01

    Individuals suffering from Werner syndrome (WS) exhibit many clinical signs of accelerated aging. While the underlying constitutional mutation leads to accelerated rates of DNA damage, it is not yet known whether WS is also associated with an increased epigenetic age according to a DNA methylation based biomarker of aging (the "Epigenetic Clock"). Using whole blood methylation data from 18 WS cases and 18 age matched controls, we find that WS is associated with increased extrinsic epigenetic age acceleration (p=0.0072) and intrinsic epigenetic age acceleration (p=0.04), the latter of which is independent of age-related changes in the composition of peripheral blood cells. A multivariate model analysis reveals that WS is associated with an increase in DNA methylation age (on average 6.4 years, p=0.011) even after adjusting for chronological age, gender, and blood cell counts. Further, WS might be associated with a reduction in naïve CD8+ T cells (p=0.025) according to imputed measures of blood cell counts. Overall, this study shows that WS is associated with an increased epigenetic age of blood cells which is independent of changes in blood cell composition. The extent to which this alteration is a cause or effect of WS disease phenotypes remains unknown.

  4. Accelerating Commercial Remote Sensing

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Through the Visiting Investigator Program (VIP) at Stennis Space Center, Community Coffee was able to use satellites to forecast coffee crops in Guatemala. Using satellite imagery, the company can produce detailed maps that separate coffee cropland from wild vegetation and show information on the health of specific crops. The data can control coffee prices and eventually may be used to optimize application of fertilizers, pesticides and irrigation. This would result in maximal crop yields, minimal pollution and lower production costs. VIP is a mechanism involving NASA funding designed to accelerate the growth of commercial remote sensing by promoting general awareness and basic training in the technology.

  5. Refrozen lead

    NASA Image and Video Library

    2017-12-08

    Closer look at a re-frozen lead in sea ice in the Bellingshausen Sea, seen from the DC-8 on Oct. 19, 2012. Credit: NASA / George Hale NASA's Operation IceBridge is an airborne science mission to study Earth's polar ice. For more information about IceBridge, visit: www.nasa.gov/icebridge NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  6. Energy Frontier Research Centers: Helping Win the Energy Innovation Race (2011 EFRC Summit Keynote Address, Secretary of Energy Chu)

    ScienceCinema

    Chu, Steven

    2017-12-21

    Secretary of Energy Steven Chu gave the keynote address at the 2011 EFRC Summit and Forum. In his talk, Secretary Chu highlighted the need to "unleash America's science and research community" to achieve energy breakthroughs. The 2011 EFRC Summit and Forum brought together the EFRC community and science and policy leaders from universities, national laboratories, industry and government to discuss "Science for our Nation's Energy Future." In August 2009, the Office of Science established 46 Energy Frontier Research Centers. The EFRCs are collaborative research efforts intended to accelerate high-risk, high-reward fundamental research, the scientific basis for transformative energy technologies of the future. These Centers involve universities, national laboratories, nonprofit organizations, and for-profit firms, singly or in partnerships, selected by scientific peer review. They are funded at $2 to $5 million per year for a total planned DOE commitment of $777 million over the initial five-year award period, pending Congressional appropriations. These integrated, multi-investigator Centers are conducting fundamental research focusing on one or more of several “grand challenges” and use-inspired “basic research needs” recently identified in major strategic planning efforts by the scientific community. The purpose of the EFRCs is to integrate the talents and expertise of leading scientists in a setting designed to accelerate research that transforms the future of energy and the environment.

  7. Relative Humidity in Limited Streamer Tubes for Stanford Linear Accelerator Center's BaBar Detector

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

    Lang, M.I.; /MIT; Convery, M.

    2005-12-15

    The BABAR Detector at the Stanford Linear Accelerator Center studies the decay of B mesons created in e{sup +}e{sup -} collisions. The outermost layer of the detector, used to detect muons and neutral hadrons created during this process, is being upgraded from Resistive Plate Chambers (RPCs) to Limited Streamer Tubes (LSTs). The standard-size LST tube consists of eight cells, where a silver-plated wire runs down the center of each. A large potential difference is placed between the wires and ground. Gas flows through a series of modules connected with tubing, typically four. LSTs must be carefully tested before installation, asmore » it will be extremely difficult to repair any damage once installed in the detector. In the testing process, the count rate in most modules showed was stable and consistent with cosmic ray rate over an approximately 500 V operating range between 5400 to 5900 V. The count in some modules, however, was shown to unexpectedly spike near the operation point. In general, the modules through which the gas first flows did not show this problem, but those further along the gas chain were much more likely to do so. The suggestion was that this spike was due to higher humidity in the modules furthest from the fresh, dry inflowing gas, and that the water molecules in more humid modules were adversely affecting the modules' performance. This project studied the effect of humidity in the modules, using a small capacitive humidity sensor (Honeywell). The sensor provided a humidity-dependent output voltage, as well as a temperature measurement from a thermistor. A full-size hygrometer (Panametrics) was used for testing and calibrating the Honeywell sensors. First the relative humidity of the air was measured. For the full calibration, a special gas-mixing setup was used, where relative humidity of the LST gas mixture could be varied from almost dry to almost fully saturated. With the sensor calibrated, a set of sensors was used to measure humidity vs

  8. Electricity: The Energy of Tomorrow (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema

    Abruna, Hector D. (Director, Energy Materials Center at Cornell); emc2 Staff

    2017-12-09

    'Electricity: the Energy of Tomorrow' was submitted by the Energy Materials Center at Cornell (emc2) to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. emc2, an EFRC directed by Hector D. Abruna at Cornell University (lead) is a partnership between Cornell and Lawrence Berkeley National Laboratory. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.

  9. Nonlinear dynamics of autonomous vehicles with limits on acceleration

    NASA Astrophysics Data System (ADS)

    Davis, L. C.

    2014-07-01

    The stability of autonomous vehicle platoons with limits on acceleration and deceleration is determined. If the leading-vehicle acceleration remains within the limits, all vehicles in the platoon remain within the limits when the relative-velocity feedback coefficient is equal to the headway time constant [k=1/h]. Furthermore, if the sensitivity α>1/h, no collisions occur. String stability for small perturbations is assumed and the initial condition is taken as the equilibrium state. Other values of k and α that give stability with no collisions are found from simulations. For vehicles with non-negligible mechanical response, simulations indicate that the acceleration-feedback-control gain might have to be dynamically adjusted to obtain optimal performance as the response time changes with engine speed. Stability is demonstrated for some perturbations that cause initial acceleration or deceleration greater than the limits, yet do not cause collisions.

  10. A National Network of Neurotechnology Centers for the BRAIN Initiative

    PubMed Central

    Alivisatos, A. Paul; Chun, Miyoung; Church, George M.; Greenspan, Ralph J.; Roukes, Michael L.; Yuste, Rafael

    2017-01-01

    We propose the creation of a national network of neurotechnology centers to enhance and accelerate the BRAIN Initiative and optimally leverage the effort and creativity of individual laboratories involved in it. As “brain observatories,” these centers could provide the critical interdisciplinary environment both for realizing ambitious and complex technologies and for providing individual investigators with access to them. PMID:26481036

  11. First muon acceleration using a radio-frequency accelerator

    NASA Astrophysics Data System (ADS)

    Bae, S.; Choi, H.; Choi, S.; Fukao, Y.; Futatsukawa, K.; Hasegawa, K.; Iijima, T.; Iinuma, H.; Ishida, K.; Kawamura, N.; Kim, B.; Kitamura, R.; Ko, H. S.; Kondo, Y.; Li, S.; Mibe, T.; Miyake, Y.; Morishita, T.; Nakazawa, Y.; Otani, M.; Razuvaev, G. P.; Saito, N.; Shimomura, K.; Sue, Y.; Won, E.; Yamazaki, T.

    2018-05-01

    Muons have been accelerated by using a radio-frequency accelerator for the first time. Negative muonium atoms (Mu- ), which are bound states of positive muons (μ+) and two electrons, are generated from μ+'s through the electron capture process in an aluminum degrader. The generated Mu- 's are initially electrostatically accelerated and injected into a radio-frequency quadrupole linac (RFQ). In the RFQ, the Mu- 's are accelerated to 89 keV. The accelerated Mu- 's are identified by momentum measurement and time of flight. This compact muon linac opens the door to various muon accelerator applications including particle physics measurements and the construction of a transmission muon microscope.

  12. Transverse vibration and buckling of a cantilevered beam with tip body under constant axial base acceleration

    NASA Technical Reports Server (NTRS)

    Storch, J.; Gates, S.

    1983-01-01

    The planar transverse bending behavior of a uniform cantilevered beam with rigid tip body subject to constant axial base acceleration was analyzed. The beam is inextensible and capable of small elastic transverse bending deformations only. Two classes of tip bodies are recognized: (1) mass centers located along the beam tip tangent line; and (2) mass centers with arbitrary offset towards the beam attachment point. The steady state response is studied for the beam end condition cases: free, tip mass, tip body with restricted mass center offset, and tip body with arbitrary mass center offset. The first three cases constitute classical Euler buckling problems, and the characteristic equation for the critical loads/accelerations are determined. For the last case a unique steady state solution exists. The free vibration response is examined for the two classes of tip body. The characteristic equation, eigenfunctions and their orthogonality properties are obtained for the case of restricted mass center offset. The vibration problem is nonhomogeneous for the case of arbitrary mass center offset. The exact solution is obtained as a sum of the steady state solution and a superposition of simple harmonic motions.

  13. Environmental lead exposure accelerates progressive diabetic nephropathy in type II diabetic patients.

    PubMed

    Huang, Wen-Hung; Lin, Ja-Liang; Lin-Tan, Dan-Tzu; Hsu, Ching-Wei; Chen, Kuan-Hsing; Yen, Tzung-Hai

    2013-01-01

    Whether environmental lead exposure has a long-term effect on progressive diabetic nephropathy in type II diabetic patients remains unclear. A total of 107 type II diabetic patients with stage 3 diabetic nephropathy (estimated glomerular filtration rate (eGFR) range, 30-60 mL/min/1.73 m(2)) with normal body lead burden (BLB) (<600  μ g/72 hr in EDTA mobilization tests) and no history of exposure to lead were prospectively followed for 2 years. Patients were divided into high-normal BLB (>80  μ g) and low-normal BLB (<80  μ g) groups. The primary outcome was a 2-fold increase in the initial creatinine levels, long-term dialysis, or death. The secondary outcome was a change in eGFR over time. Forty-five patients reached the primary outcome within 2 years. Although there were no differences in baseline data and renal function, progressive nephropathy was slower in the low-normal BLB group than that in the high-normal BLB group. During the study period, we demonstrated that each 100  μ g increment in BLB and each 10  μ g increment in blood lead levels could decrease GFR by 2.2 mL/min/1.72 m(2) and 3.0 mL/min/1.72 m(2) (P = 0.005), respectively, as estimated by generalized equations. Moreover, BLB was associated with increased risk of achieving primary outcome. Environmental exposure to lead may have a long-term effect on progressive diabetic nephropathy in type II diabetic patients.

  14. Test Control Center

    NASA Image and Video Library

    2000-10-25

    At the test observation periscope in the Test Control Center exhibit in StenniSphere at the John C. Stennis Space Center in Hancock County, Miss., visitors can observe a test of a Space Shuttle Main Engine exactly as test engineers might see it during a real engine test. The Test Control Center exhibit exactly simulates not only the test control environment, but also the procedure of testing a rocket engine. Designed to entertain while educating, StenniSphere includes informative dispays and exhibits from NASA's lead center for rocket propulsion and remote sensing applications. StenniSphere is open free of charge from 9 a.m. to 5 p.m. daily.

  15. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  16. Accelerating Drug Development: Antiviral Therapies for Emerging Viruses as a Model.

    PubMed

    Everts, Maaike; Cihlar, Tomas; Bostwick, J Robert; Whitley, Richard J

    2017-01-06

    Drug discovery and development is a lengthy and expensive process. Although no one, simple, single solution can significantly accelerate this process, steps can be taken to avoid unnecessary delays. Using the development of antiviral therapies as a model, we describe options for acceleration that cover target selection, assay development and high-throughput screening, hit confirmation, lead identification and development, animal model evaluations, toxicity studies, regulatory issues, and the general drug discovery and development infrastructure. Together, these steps could result in accelerated timelines for bringing antiviral therapies to market so they can treat emerging infections and reduce human suffering.

  17. Acceleration Modes and Transitions in Pulsed Plasma Accelerators

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A.; Greve, Christine M.

    2018-01-01

    Pulsed plasma accelerators typically operate by storing energy in a capacitor bank and then discharging this energy through a gas, ionizing and accelerating it through the Lorentz body force. Two plasma accelerator types employing this general scheme have typically been studied: the gas-fed pulsed plasma thruster and the quasi-steady magnetoplasmadynamic (MPD) accelerator. The gas-fed pulsed plasma accelerator is generally represented as a completely transient device discharging in approximately 1-10 microseconds. When the capacitor bank is discharged through the gas, a current sheet forms at the breech of the thruster and propagates forward under a j (current density) by B (magnetic field) body force, entraining propellant it encounters. This process is sometimes referred to as detonation-mode acceleration because the current sheet representation approximates that of a strong shock propagating through the gas. Acceleration of the initial current sheet ceases when either the current sheet reaches the end of the device and is ejected or when the current in the circuit reverses, striking a new current sheet at the breech and depriving the initial sheet of additional acceleration. In the quasi-steady MPD accelerator, the pulse is lengthened to approximately 1 millisecond or longer and maintained at an approximately constant level during discharge. The time over which the transient phenomena experienced during startup typically occur is short relative to the overall discharge time, which is now long enough for the plasma to assume a relatively steady-state configuration. The ionized gas flows through a stationary current channel in a manner that is sometimes referred to as the deflagration-mode of operation. The plasma experiences electromagnetic acceleration as it flows through the current channel towards the exit of the device. A device that had a short pulse length but appeared to operate in a plasma acceleration regime different from the gas-fed pulsed plasma

  18. G-Equivalent Acceleration Tolerance in the Eutardigrade Species Hypsibius dujardini

    NASA Astrophysics Data System (ADS)

    Vasanthan, Tarushika; Alejaldre, Lorea; Hider, Jessica; Patel, Shreya; Husain, Nabiha; Umapathisivam, Bavithra; Stone, Jonathon

    2017-01-01

    Tardigrades are microscopic organisms renowned for their ability to survive extreme environmental conditions. Tardigrade extreme-tolerance research has centered on the ability to withstand desiccation, low and high temperatures, and high hydrostatic pressure and radiation levels. Tardigrade tolerance to hypergravity, however, has yet to be described. We used the eutardigrade species Hypsibius dujardini to investigate short-term tolerance to g-equivalent accelerations (i.e., mimicking g-forces). Data obtained from specimens centrifuged between 3421g and 16,060g for 1 min inclusively reveal tolerance in an acceleration-dependent relation, with lower survivorship and egg production at higher accelerations. This is the first study to demonstrate tardigrade potential for tolerance to hypergravity and describe expected effects on tardigrade survival and reproduction. These findings will prove to be useful in lithopanspermia research (i.e., viable spread in meteoritic rocks).

  19. Airy Wave Packets Accelerating in Space-Time

    NASA Astrophysics Data System (ADS)

    Kondakci, H. Esat; Abouraddy, Ayman F.

    2018-04-01

    Although diffractive spreading is an unavoidable feature of all wave phenomena, certain waveforms can attain propagation invariance. A lesser-explored strategy for achieving optical self-similar propagation exploits the modification of the spatiotemporal field structure when observed in reference frames moving at relativistic speeds. For such an observer, it is predicted that the associated Lorentz boost can bring to a halt the axial dynamics of a wave packet of an arbitrary profile. This phenomenon is particularly striking in the case of a self-accelerating beam—such as an Airy beam—whose peak normally undergoes a transverse displacement upon free propagation. Here we synthesize an acceleration-free Airy wave packet that travels in a straight line by deforming its spatiotemporal spectrum to reproduce the impact of a Lorentz boost. The roles of the axial spatial coordinate and time are swapped, leading to "time diffraction" manifested in self-acceleration observed in the propagating Airy wave-packet frame.

  20. Harnessing person-generated health data to accelerate patient-centered outcomes research: the Crohn’s and Colitis Foundation of America PCORnet Patient Powered Research Network (CCFA Partners)

    PubMed Central

    Sandler, Robert S; Long, Millie D; Ahrens, Sean; Burris, Jessica L; Martin, Christopher F; Anton, Kristen; Robb, Amber; Caruso, Thomas P; Jaeger, Elizabeth L; Chen, Wenli; Clark, Marshall; Myers, Kelly; Dobes, Angela; Kappelman, Michael D

    2016-01-01

    The Crohn’s and Colitis Foundation of America Partners Patient-Powered Research Network (PPRN) seeks to advance and accelerate comparative effectiveness and translational research in inflammatory bowel diseases (IBDs). Our IBD-focused PCORnet PPRN has been designed to overcome the major obstacles that have limited patient-centered outcomes research in IBD by providing the technical infrastructure, patient governance, and patient-driven functionality needed to: 1) identify, prioritize, and undertake a patient-centered research agenda through sharing person-generated health data; 2) develop and test patient and provider-focused tools that utilize individual patient data to improve health behaviors and inform health care decisions and, ultimately, outcomes; and 3) rapidly disseminate new knowledge to patients, enabling them to improve their health. The Crohn’s and Colitis Foundation of America Partners PPRN has fostered the development of a community of citizen scientists in IBD; created a portal that will recruit, retain, and engage members and encourage partnerships with external scientists; and produced an efficient infrastructure for identifying, screening, and contacting network members for participation in research. PMID:26911821

  1. Adaptive and accelerated tracking-learning-detection

    NASA Astrophysics Data System (ADS)

    Guo, Pengyu; Li, Xin; Ding, Shaowen; Tian, Zunhua; Zhang, Xiaohu

    2013-08-01

    An improved online long-term visual tracking algorithm, named adaptive and accelerated TLD (AA-TLD) based on Tracking-Learning-Detection (TLD) which is a novel tracking framework has been introduced in this paper. The improvement focuses on two aspects, one is adaption, which makes the algorithm not dependent on the pre-defined scanning grids by online generating scale space, and the other is efficiency, which uses not only algorithm-level acceleration like scale prediction that employs auto-regression and moving average (ARMA) model to learn the object motion to lessen the detector's searching range and the fixed number of positive and negative samples that ensures a constant retrieving time, but also CPU and GPU parallel technology to achieve hardware acceleration. In addition, in order to obtain a better effect, some TLD's details are redesigned, which uses a weight including both normalized correlation coefficient and scale size to integrate results, and adjusts distance metric thresholds online. A contrastive experiment on success rate, center location error and execution time, is carried out to show a performance and efficiency upgrade over state-of-the-art TLD with partial TLD datasets and Shenzhou IX return capsule image sequences. The algorithm can be used in the field of video surveillance to meet the need of real-time video tracking.

  2. Tilt perception during dynamic linear acceleration.

    PubMed

    Seidman, S H; Telford, L; Paige, G D

    1998-04-01

    Head tilt is a rotation of the head relative to gravity, as exemplified by head roll or pitch from the natural upright orientation. Tilt stimulates both the otolith organs, owing to shifts in gravitational orientation, and the semicircular canals in response to head rotation, which in turn drive a variety of behavioral and perceptual responses. Studies of tilt perception typically have not adequately isolated otolith and canal inputs or their dynamic contributions. True tilt cannot readily dissociate otolith from canal influences. Alternatively, centrifugation generates centripetal accelerations that simulate tilt, but still entails a rotatory (canal) stimulus during important periods of the stimulus profiles. We reevaluated the perception of head tilt in humans, but limited the stimulus to linear forces alone, thus isolating the influence of otolith inputs. This was accomplished by employing a centrifugation technique with a variable-radius spinning sled. This allowed us to accelerate the sled to a constant angular velocity (128 degrees/s), with the subject centered, and then apply dynamic centripetal accelerations after all rotatory perceptions were extinguished. These stimuli were presented in the subjects' naso-occipital axis by translating the subjects 50 cm eccentrically either forward or backward. Centripetal accelerations were thus induced (0.25 g), which combined with gravity to yield a dynamically shifting gravitoinertial force simulating pitch-tilt, but without actually rotating the head. A magnitude-estimation task was employed to characterize the dynamic perception of pitch-tilt. Tilt perception responded sluggishly to linear acceleration, typically reaching a peak after 10-30 s. Tilt perception also displayed an adaptation phenomenon. Adaptation was manifested as a per-stimulus decline in perceived tilt during prolonged stimulation and a reversal aftereffect upon return to zero acceleration (i.e., recentering the subject). We conclude that otolith

  3. NCI Technology Transfer Center | TTC

    Cancer.gov

    The National Cancer Institute’s Technology Transfer Center (TTC) facilitates partnerships between the NIH research laboratories and external partners. With specialized teams, TTC guides the interactions of our partners from the point of discovery to patenting, from invention development to licensing. We play a key role in helping to accelerate development of cutting-edge research by connecting our partners to NIH’s world-class researchers, facilities, and knowledge.

  4. Teaching and Research with Accelerators at Tarleton State University

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

    Marble, Daniel K.

    2009-03-10

    Tarleton State University students began performing both research and laboratory experiments using accelerators in 1998 through visitation programs at the University of North Texas, US Army Research Laboratory, and the Naval Surface Warfare Center at Carderock. In 2003, Tarleton outfitted its new science building with a 1 MV pelletron that was donated by the California Institution of Technology. The accelerator has been upgraded and supports a wide range of classes for both the Physics program and the ABET accredited Engineering Physics program as well as supplying undergraduate research opportunities on campus. A discussion of various laboratory activities and research projectsmore » performed by Tarleton students will be presented.« less

  5. A National Network of Neurotechnology Centers for the BRAIN Initiative.

    PubMed

    Alivisatos, A Paul; Chun, Miyoung; Church, George M; Greenspan, Ralph J; Roukes, Michael L; Yuste, Rafael

    2015-11-04

    We propose the creation of a national network of neurotechnology centers to enhance and accelerate the BRAIN Initiative and optimally leverage the effort and creativity of individual laboratories involved in it. As "brain observatories," these centers could provide the critical interdisciplinary environment both for realizing ambitious and complex technologies and for providing individual investigators with access to them. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Timescale Correlation between Marine Atmospheric Exposure and Accelerated Corrosion Testing

    NASA Technical Reports Server (NTRS)

    Montgomery, Eliza L.; Calle, Luz Marina; Curran, Jerone C.; Kolody, Mark R.

    2011-01-01

    Evaluation of metal-based structures has long relied on atmospheric exposure test sites to determine corrosion resistance in marine environments. Traditional accelerated corrosion testing relies on mimicking the exposure conditions, often incorporating salt spray and ultraviolet (UV) radiation, and exposing the metal to continuous or cyclic conditions of the corrosive environment. Their success for correlation to atmospheric exposure is often a concern when determining the timescale to which the accelerated tests can be related. Accelerated laboratory testing, which often focuses on the electrochemical reactions that occur during corrosion conditions, has yet to be universally accepted as a useful tool in predicting the long term service life of a metal despite its ability to rapidly induce corrosion. Although visual and mass loss methods of evaluating corrosion are the standard and their use is imperative, a method that correlates timescales from atmospheric exposure to accelerated testing would be very valuable. This work uses surface chemistry to interpret the chemical changes occurring on low carbon steel during atmospheric and accelerated corrosion conditions with the objective of finding a correlation between its accelerated and long-term corrosion performance. The current results of correlating data from marine atmospheric exposure conditions at the Kennedy Space Center beachside corrosion test site, alternating seawater spray, and immersion in typical electrochemical laboratory conditions, will be presented. Key words: atmospheric exposure, accelerated corrosion testing, alternating seawater spray, marine, correlation, seawater, carbon steel, long-term corrosion performance prediction, X-ray photoelectron spectroscopy.

  7. Vacuum Plasma Spray Forming of Tungsten Lorentz Force Accelerator Components

    NASA Technical Reports Server (NTRS)

    Zimmerman, Frank R.

    2001-01-01

    The Vacuum Plasma Spray (VPS) Laboratory at NASA's Marshall Space Flight Center has developed and demonstrated a fabrication technique using the VPS process to form anode sections for a Lorentz force accelerator from tungsten. Lorentz force accelerators are an attractive form of electric propulsion that provides continuous, high-efficiency propulsion at useful power levels for such applications as orbit transfers or deep space missions. The VPS process is used to deposit refractory metals such as tungsten onto a graphite mandrel of the desired shape. Because tungsten is reactive at high temperatures, it is thermally sprayed in an inert environment where the plasma gun melts and accelerates the metal powder onto the mandrel. A three-axis robot inside the chamber controls the motion of the plasma spray torch. A graphite mandrel acts as a male mold, forming the required contour and dimensions of the inside surface of the anode. This paper describes the processing techniques, design considerations, and process development associated with the VPS forming of the Lorentz force accelerator.

  8. Techniques for correcting velocity and density fluctuations of ion beams in ion inducti on accelerators

    NASA Astrophysics Data System (ADS)

    Woo, K. M.; Yu, S. S.; Barnard, J. J.

    2013-06-01

    It is well known that the imperfection of pulse power sources that drive the linear induction accelerators can lead to time-varying fluctuation in the accelerating voltages, which in turn leads to longitudinal emittance growth. We show that this source of emittance growth is correctable, even in space-charge dominated beams with significant transients induced by space-charge waves. Two correction methods are proposed, and their efficacy in reducing longitudinal emittance is demonstrated with three-dimensional particle-in-cell simulations.

  9. Plasma Accelerators Race to 10 GeV and Beyond

    NASA Astrophysics Data System (ADS)

    Katsouleas, Tom

    2005-10-01

    This paper reviews the concepts, recent progress and current challenges for realizing the tremendous electric fields in relativistic plasma waves for applications ranging from tabletop particle accelerators to high-energy physics. Experiments in the 90's on laser-driven plasma wakefield accelerators at several laboratories around the world demonstrated the potential for plasma wakefields to accelerate intense bunches of self-trapped particles at rates as high as 100 GeV/m in mm-scale gas jets. These early experiments offered impressive gradients but large energy spread (100%) and short interaction lengths. Major breakthroughs have recently occurred on both fronts. Three groups (LBL-US, LOA-France and RAL-UK) have now entered a new regime of laser wakefield acceleration resulting in 100 MeV mono-energetic beams with up to nanoCoulombs of charge and very small angular spread. Simulations suggest that current lasers are just entering this new regime, and the scaling to higher energies appears attractive. In parallel with the progress in laser-driven wakefields, particle-beam driven wakefield accelerators are making large strides. A series of experiments using the 30 GeV beam of the Stanford Linear Accelerator Center (SLAC) has demonstrated high-gradient acceleration of electrons and positrons in meter-scale plasmas. The UCLA/USC/SLAC collaboration has accelerated electrons beyond 1 GeV and is aiming at 10 GeV in 30 cm as the next step toward a ``plasma afterburner,'' a concept for doubling the energy of a high-energy collider in a few tens of meters of plasma. In addition to wakefield acceleration, these and other experiments have demonstrated the rich physics bounty to be reaped from relativistic beam-plasma interactions. This includes plasma lenses capable of focusing particle beams to the highest density ever produced, collective radiation mechanisms capable of generating high-brightness x-ray beams, collective refraction of particles at a plasma interface, and

  10. A rationale for lowering the blood lead action level from 10 to 2 μg/dL☆

    PubMed Central

    Gilbert, Steven G.; Weiss, Bernard

    2008-01-01

    Fifteen years ago, in 1991, the U.S. Centers for Disease Control and Prevention (CDC) established 10 μg/dL as the lowest level of concern for children’s blood lead levels. This value is extremely important because, historically, policy makers and public health officials generally have acted to remove sources of lead exposure only after the CDC’s level of concern had been exceeded. A growing body of evidence, however, reveals that blood lead levels below 10 μg/dL may impair neurobehavioral development. There is now sufficient and compelling scientific evidence for the CDC to lower the blood lead action level in children. This review argues that a level of 2 μg/dL is a useful and feasible replacement. Although it can be argued, in turn, that no threshold for the health effects of lead is demonstrable, analytically a blood level of 2 μg/dL is readily and accurately measured and provides a benchmark for successful prevention. Lowering the level of concern would encourage and accelerate the investments needed to ensure that children are protected from lead exposure in their homes, schools, and play settings. Such a program would also offer economic advantages because of the coupling between lead, educational attainment, earnings and anti-social conduct. By lowering the blood action level, CDC will promote policies and initiatives designed to further reduce children’s exposure to this potent developmental neurotoxicant. PMID:16889836

  11. Data Center Energy Practitioner (DCEP) Program

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

    Traber, Kim; Salim, Munther; Sartor, Dale A.

    2016-02-02

    The main objective for the DCEP program is to raise the standards of those involved in energy assessments of data centers to accelerate energy savings. The program is driven by the fact that significant knowledge, training, and skills are required to perform accurate energy assessments. The program will raise the confidence level in energy assessments in data centers. For those who pass the exam, the program will recognize them as Data Center Energy Practitioners (DCEPs) by issuing a certificate. Hardware req.: PC, MAC; Software Req.: Windows; Related/Auxiliary software--MS Office; Type of files: executable modules, user guide; Documentation: e-user manual; Documentation:more » http://www.1.eere.energy.gov/industry/datacenters/ 12/10/15-New Documentation URL: https://datacenters.lbl.gov/dcep« less

  12. Testing of Composite Fan Vanes With Erosion-Resistant Coating Accelerated

    NASA Technical Reports Server (NTRS)

    Bowman, Cheryl L.; Sutter, James K.; Otten, Kim D.; Samorezov, Sergey; Perusek, Gail P.

    2004-01-01

    The high-cycle fatigue of composite stator vanes provided an accelerated life-state prior to insertion in a test stand engine. The accelerated testing was performed in the Structural Dynamics Laboratory at the NASA Glenn Research Center under the guidance of Structural Mechanics and Dynamics Branch personnel. Previous research on fixturing and test procedures developed at Glenn determined that engine vibratory conditions could be simulated for polymer matrix composite vanes by using the excitation of a combined slip table and electrodynamic shaker in Glenn's Structural Dynamics Laboratory. Bench-top testing gave researchers the confidence to test the coated vanes in a full-scale engine test.

  13. Ion acceleration via TNSA near and beyond the relativistic transparency limit

    NASA Astrophysics Data System (ADS)

    Schumacher, Douglass; Poole, Patrick; Cochran, Ginevra; Willis, Christopher

    2017-10-01

    Ultra-intense laser-based ion acceleration can proceed via several mechanisms whose fundamental operation and interplay with each other are still not well understood. The details of Relativistically Induced Transparency (RIT) and its impact on ultra-thin target acceleration are of interest for fundamental studies and to progress toward applications requiring controlled, high energy secondary radiation, e.g. hadron cancer therapy. Liquid crystal film targets formed in-situ with thickness control between 10 nm and > 50 μm uniquely allow study of how ion acceleration varies with target thickness. Several recent studies have investigated Target Normal Sheath Acceleration (TNSA) down to the thickness at which RIT occurs, with a wide range of laser conditions (energy, pulse duration, and contrast), using various ion and optical diagnostics to ascertain acceleration mechanisms and quality. Observation of target-normal directed ion acceleration enhancement at the RIT thickness onset will be discussed, including analysis of ion spatial and spectral features as well as particle-in-cell simulations investigating the underlying physical processes. This material is based upon work supported by the AFOSR under Award Number FA9550-14-1-0085, by the NNSA under DE-NA0003107, and by computing time from the Ohio Supercomputer Center.

  14. Complex flow morphologies in shock-accelerated gaseous flows

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Vorobieff, P.; Orlicz, G.; Palekar, A.; Tomkins, C.; Goodenough, C.; Marr-Lyon, M.; Prestridge, K. P.; Benjamin, R. F.

    2007-11-01

    A Mach 1.2 planar shock wave impulsively and simultaneously accelerates a row of three heavy gas (SF 6) cylinders surrounded by a lighter gas (air), producing pairs of vortex columns. The heavy gas cylinders (nozzle diameter D) are initially equidistant in the spanwise direction (center to center spacing S), with S/D=1.5. The interaction of the vortex columns is investigated with planar laser-induced fluorescence (PLIF) in the plane normal to the axes of the cylinders. Several distinct post-shock morphologies are observed, apparently due to rather small variations of the initial conditions. We report the variation of the streamwise and spanwise growth rates of the integral scales for these flow morphologies.

  15. Construction and comparison of Louisiana's conventional and alternative base courses under accelerated loading

    DOT National Transportation Integrated Search

    1998-08-01

    The report describes the first testing series, Phase, of the first project, Experiment 1, with the Louisiana Transportation Research Center Accelerated Loading Facility. The background to the project is described and details of the trial pavements si...

  16. Electricity: The Energy of Tomorrow (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

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

    None

    "Electricity: the Energy of Tomorrow" was submitted by the Energy Materials Center at Cornell (emc2) to the "Life at the Frontiers of Energy Research" video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. emc2, an EFRC directed by Hector D. Abruna at Cornell University (lead) is a partnership between Cornell and Lawrence Berkeley National Laboratory. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs)more » in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.« less

  17. Covariant Uniform Acceleration

    NASA Astrophysics Data System (ADS)

    Friedman, Yaakov; Scarr, Tzvi

    2013-04-01

    We derive a 4D covariant Relativistic Dynamics Equation. This equation canonically extends the 3D relativistic dynamics equation , where F is the 3D force and p = m0γv is the 3D relativistic momentum. The standard 4D equation is only partially covariant. To achieve full Lorentz covariance, we replace the four-force F by a rank 2 antisymmetric tensor acting on the four-velocity. By taking this tensor to be constant, we obtain a covariant definition of uniformly accelerated motion. This solves a problem of Einstein and Planck. We compute explicit solutions for uniformly accelerated motion. The solutions are divided into four Lorentz-invariant types: null, linear, rotational, and general. For null acceleration, the worldline is cubic in the time. Linear acceleration covariantly extends 1D hyperbolic motion, while rotational acceleration covariantly extends pure rotational motion. We use Generalized Fermi-Walker transport to construct a uniformly accelerated family of inertial frames which are instantaneously comoving to a uniformly accelerated observer. We explain the connection between our approach and that of Mashhoon. We show that our solutions of uniformly accelerated motion have constant acceleration in the comoving frame. Assuming the Weak Hypothesis of Locality, we obtain local spacetime transformations from a uniformly accelerated frame K' to an inertial frame K. The spacetime transformations between two uniformly accelerated frames with the same acceleration are Lorentz. We compute the metric at an arbitrary point of a uniformly accelerated frame. We obtain velocity and acceleration transformations from a uniformly accelerated system K' to an inertial frame K. We introduce the 4D velocity, an adaptation of Horwitz and Piron s notion of "off-shell." We derive the general formula for the time dilation between accelerated clocks. We obtain a formula for the angular velocity of a uniformly accelerated object. Every rest point of K' is uniformly accelerated, and

  18. Novel target design for enhanced laser driven proton acceleration

    NASA Astrophysics Data System (ADS)

    Dalui, Malay; Kundu, M.; Tata, Sheroy; Lad, Amit D.; Jha, J.; Ray, Krishanu; Krishnamurthy, M.

    2017-09-01

    We demonstrate a simple method of preparing structured target for enhanced laser-driven proton acceleration under target-normal-sheath-acceleration scheme. A few layers of genetically modified, clinically grown micron sized E. Coli bacteria cell coated on a thin metal foil has resulted in an increase in the maximum proton energy by about 1.5 times and the total proton yield is enhanced by approximately 25 times compared to an unstructured reference foil at a laser intensity of 1019 W/cm2. Particle-in-cell simulations on the system shows that the structures on the target-foil facilitates anharmonic resonance, contributing to enhanced hot electron production which leads to stronger accelerating field. The effect is observed to grow as the number of structures is increased in the focal area of the laser pulse.

  19. Linking School and Work to Accelerate Student Results.

    ERIC Educational Resources Information Center

    Workforce Economics, 1999

    1999-01-01

    This serial issue focusing on the theme of "School-to-Work." The two articles it contains describe promising practices that benefit individual students who participate. The first article, "Connecting the Dots: Linking School and Work to Accelerate Student Results," examines how schools and businesses are linking up, leading to benefits for…

  20. Analyzing radial acceleration with a smartphone acceleration sensor

    NASA Astrophysics Data System (ADS)

    Vogt, Patrik; Kuhn, Jochen

    2013-03-01

    This paper continues the sequence of experiments using the acceleration sensor of smartphones (for description of the function and the use of the acceleration sensor, see Ref. 1) within this column, in this case for analyzing the radial acceleration.

  1. FFAGs: Front-end for neutrino factories and medical accelerators

    NASA Astrophysics Data System (ADS)

    Mori, Yoshiharu

    The idea of Fixed Field Alternating Gradient (FFAG) accelerator was originated by different people and groups in the early 1950s. It was independently introduced by Ohkawa [Ohkawa (1953)], Symon et al. [Symon et al. (1956)], and Kolomensky [Kolomensky and Lebedev (1966)] when the strong Alternate Gradient (AG) focusing and the phase stability schemes were applied to particle acceleration. The first FFAG electron model was developed in the MURA accelerator project led by Kerst and Cole in the late 1950s. Since then, they have fabricated several electron models in the early 1960s [Symon et al. (1956)]. However, the studies did not lead to a single practical FFAG accelerator for the following 50 years. Because of the difficulties of treating non-linear magnetic field and RF acceleration for non-relativistic particles, the proton FFAG, especially, was not accomplished until recently. In 2000, the FFAG concept was revived with the world's first proton FFAG (POP) which was developed at KEK [Aiba (2000); Mori (1999)]. Since then, in many places [Berg (2004); Johnstone et al. (2004); Mori (2011); Ruggiero (2004); Trbojevic (2004)], FFAGs have been developed and constructed...

  2. G-Equivalent Acceleration Tolerance in the Eutardigrade Species Hypsibius dujardini.

    PubMed

    Vasanthan, Tarushika; Alejaldre, Lorea; Hider, Jessica; Patel, Shreya; Husain, Nabiha; Umapathisivam, Bavithra; Stone, Jonathon

    2017-01-01

    Tardigrades are microscopic organisms renowned for their ability to survive extreme environmental conditions. Tardigrade extreme-tolerance research has centered on the ability to withstand desiccation, low and high temperatures, and high hydrostatic pressure and radiation levels. Tardigrade tolerance to hypergravity, however, has yet to be described. We used the eutardigrade species Hypsibius dujardini to investigate short-term tolerance to g-equivalent accelerations (i.e., mimicking g-forces). Data obtained from specimens centrifuged between 3421g and 16,060g for 1 min inclusively reveal tolerance in an acceleration-dependent relation, with lower survivorship and egg production at higher accelerations. This is the first study to demonstrate tardigrade potential for tolerance to hypergravity and describe expected effects on tardigrade survival and reproduction. These findings will prove to be useful in lithopanspermia research (i.e., viable spread in meteoritic rocks). Key Words: Astrobiology-Extreme tolerance-Hypergravity-Tardigrade. Astrobiology 17, 55-60.

  3. Laser-plasma mirrors: from electron acceleration to harmonics generation

    NASA Astrophysics Data System (ADS)

    Thévenet, Maxence; Bocoum, Maïmouna; Faure, Jérôme; Leblanc, Adrien; Vincenti, Henri; Quéré, Fabien

    2016-10-01

    Accelerating electrons in the > 10 TV/m fields inside an ultrashort ultraintense laser pulse has been a long-standing goal in experimental physics, motivated by promising theoretical predictions. The biggest hurdle was to have electrons injected in the center of the laser pulse. Recent experimental and numerical results showed that this problem could be solved using a plasma mirror, i.e. an overdense plasma with a sharp (leading to a 10 MeV 3 nC electron beam. Using particle-in-cell simulations, the ejection process was identified as a push-pull mechanism occuring at each laser period, resulting in a train of attosecond electron bunches injected in the reflected field. We present a study and a model of this process, and show the gradient characteristic length is the crucial parameter for this phenomenon. Finally, the electron ejection process was put into perspective with respect to the high harmonic generation mechanisms on plasma mirrors, giving new insights into the motion of the plasma mirror surface. funded by the European Research Council, Contract No. 306708, ERC Starting Grant FEMTOELEC.

  4. Electron Bulk Acceleration and Thermalization at Earth's Quasiperpendicular Bow Shock.

    PubMed

    Chen, L-J; Wang, S; Wilson, L B; Schwartz, S; Bessho, N; Moore, T; Gershman, D; Giles, B; Malaspina, D; Wilder, F D; Ergun, R E; Hesse, M; Lai, H; Russell, C; Strangeway, R; Torbert, R B; F-Vinas, A; Burch, J; Lee, S; Pollock, C; Dorelli, J; Paterson, W; Ahmadi, N; Goodrich, K; Lavraud, B; Le Contel, O; Khotyaintsev, Yu V; Lindqvist, P-A; Boardsen, S; Wei, H; Le, A; Avanov, L

    2018-06-01

    Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating.

  5. Electron Bulk Acceleration and Thermalization at Earth's Quasiperpendicular Bow Shock

    NASA Astrophysics Data System (ADS)

    Chen, L.-J.; Wang, S.; Wilson, L. B.; Schwartz, S.; Bessho, N.; Moore, T.; Gershman, D.; Giles, B.; Malaspina, D.; Wilder, F. D.; Ergun, R. E.; Hesse, M.; Lai, H.; Russell, C.; Strangeway, R.; Torbert, R. B.; F.-Vinas, A.; Burch, J.; Lee, S.; Pollock, C.; Dorelli, J.; Paterson, W.; Ahmadi, N.; Goodrich, K.; Lavraud, B.; Le Contel, O.; Khotyaintsev, Yu. V.; Lindqvist, P.-A.; Boardsen, S.; Wei, H.; Le, A.; Avanov, L.

    2018-06-01

    Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating.

  6. Hydrogen accelerated fatigue crack growth of friction stir welded X52 steel pipe

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

    Ronevich, Joseph Allen; Somerday, Brian P.; Feng, Zhili

    Friction stir welded steel pipelines were tested in high pressure hydrogen gas to examine the effects of hydrogen accelerated fatigue crack growth. Fatigue crack growth rate (da/dN) vs. stress-intensity factor range (ΔK) relationships were measured for an X52 friction stir welded pipe tested in 21 MPa hydrogen gas at a frequency of 1 Hz and R = 0.5. Tests were performed on three regions: base metal (BM), center of friction stir weld (FSW), and 15 mm off-center of the weld. For all three material regions, tests in hydrogen exhibited accelerated fatigue crack growth rates that exceeded an order of magnitudemore » compared to companion tests in air. Among tests in hydrogen, fatigue crack growth rates were modestly higher in the FSW than the BM and 15 mm off-center tests. Select regions of the fracture surfaces associated with specified ΔK levels were examined which revealed intergranular fracture in the BM and 15 mm off-center specimens but an absence of intergranular features in the FSW specimens. In conclusion, the X52 friction stir weld and base metal tested in hydrogen exhibited fatigue crack growth rate relationships that are comparable to those for conventional arc welded steel pipeline of similar strength found in the literature.« less

  7. Hydrogen accelerated fatigue crack growth of friction stir welded X52 steel pipe

    DOE PAGES

    Ronevich, Joseph Allen; Somerday, Brian P.; Feng, Zhili

    2016-11-17

    Friction stir welded steel pipelines were tested in high pressure hydrogen gas to examine the effects of hydrogen accelerated fatigue crack growth. Fatigue crack growth rate (da/dN) vs. stress-intensity factor range (ΔK) relationships were measured for an X52 friction stir welded pipe tested in 21 MPa hydrogen gas at a frequency of 1 Hz and R = 0.5. Tests were performed on three regions: base metal (BM), center of friction stir weld (FSW), and 15 mm off-center of the weld. For all three material regions, tests in hydrogen exhibited accelerated fatigue crack growth rates that exceeded an order of magnitudemore » compared to companion tests in air. Among tests in hydrogen, fatigue crack growth rates were modestly higher in the FSW than the BM and 15 mm off-center tests. Select regions of the fracture surfaces associated with specified ΔK levels were examined which revealed intergranular fracture in the BM and 15 mm off-center specimens but an absence of intergranular features in the FSW specimens. In conclusion, the X52 friction stir weld and base metal tested in hydrogen exhibited fatigue crack growth rate relationships that are comparable to those for conventional arc welded steel pipeline of similar strength found in the literature.« less

  8. Coordinating Educational Assessment Across College Centers.

    ERIC Educational Resources Information Center

    Churchill, Ruth; And Others

    An operational model developed as a result of a systematic analysis of three distinctly different Antioch centers--Juarez Lincoln University, Philadelphia Graduate Center, and Antioch-New England (the Keene Center)--is presented. Juarez Lincoln offers a 15-month program leading to the Master of Education degree. Many of the students are Mexican…

  9. CABS: Green Energy for Our Nation's Future (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

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

    None

    "CABS: Green Energy for our Nation's Future" was submitted by the Center for Advanced Biofuel Systems (CABS) to the "Life at the Frontiers of Energy Research" video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. CABS, an EFRC directed by Jan Jaworski at the Donald Danforth Plant Science Center is a partnership of scientists from five institutions: Donald Danforth Plant Science Center (lead), Michigan State University, the University of Nebraska, New Mexico Consortium/LANL, and Washington State University. Themore » Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.« less

  10. Empirical development of ground acceleration, velocity, and displacement for accidental explosions at J5 or the proposed large altitude rocket cell at Arnold Engineering Development Center

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

    Davis, B.C.

    This study is an assessment of the ground shock which may be generated in the event of an accidental explosion at J5 or the Proposed Large Altitude Rocket Cell (LARC) at the Arnold Engineering Development Center (AEDC). The assessment is accomplished by reviewing existing empirical relationships for predicting ground motion from ground shock. These relationships are compared with data for surface explosions at sites with similar geology and with yields similar to expected conditions at AEDC. Empirical relationships are developed from these data and a judgment made whether to use existing empirical relationships or the relationships developed in this study.more » An existing relationship (Lipner et al.) is used to predict velocity; the empirical relationships developed in the course of this study are used to predict acceleration and displacement. The ground motions are presented in table form and as contour plots. Included also is a discussion of damage criteria from blast and earthquake studies. This report recommends using velocity rather than acceleration as an indicator of structural blast damage. It is recommended that v = 2 ips (v = .167 fps) be used as the damage threshold value (no major damage for v less than or equal to 2 ips). 13 references, 25 figures, 6 tables.« less

  11. The Light Ion Pulsed Power Induction Accelerator for ETF

    DTIC Science & Technology

    1995-07-01

    the technical development necessary to demonstrate scientific and engineering feasibility for fusion energy production with a reprated driver. In...order for ETF to be cost effective, the accelerator system must be able to drive several target chambers which will test various Inertial Fusion ... Energy (IFE) reactor technologies. We envision an elevator system positioning and removing multiple target chambers from the center area of the ion beam

  12. Risk and Infrastructure Science Center - Global Security Sciences

    Science.gov Websites

    delivers scientific tools and methodologies to inform decision making regarding the most challenging Sciences ASD Accelerator Systems AES APS Engineering Support XSD X-ray Science Physical Sciences and Leadership Strategic Alliance for Global Energy Solutions Overview Leadership Systems Science Center Overview

  13. Accelerators, Beams And Physical Review Special Topics - Accelerators And Beams

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

    Siemann, R.H.; /SLAC

    Accelerator science and technology have evolved as accelerators became larger and important to a broad range of science. Physical Review Special Topics - Accelerators and Beams was established to serve the accelerator community as a timely, widely circulated, international journal covering the full breadth of accelerators and beams. The history of the journal and the innovations associated with it are reviewed.

  14. A review of ion sources for medical accelerators (invited)

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

    Muramatsu, M.; Kitagawa, A.

    2012-02-15

    There are two major medical applications of ion accelerators. One is a production of short-lived isotopes for radionuclide imaging with positron emission tomography and single photon emission computer tomography. Generally, a combination of a source for negative ions (usually H- and/or D-) and a cyclotron is used; this system is well established and distributed over the world. Other important medical application is charged-particle radiotherapy, where the accelerated ion beam itself is being used for patient treatment. Two distinctly different methods are being applied: either with protons or with heavy-ions (mostly carbon ions). Proton radiotherapy for deep-seated tumors has become widespreadmore » since the 1990s. The energy and intensity are typically over 200 MeV and several 10{sup 10} pps, respectively. Cyclotrons as well as synchrotrons are utilized. The ion source for the cyclotron is generally similar to the type for production of radioisotopes. For a synchrotron, one applies a positive ion source in combination with an injector linac. Carbon ion radiotherapy awakens a worldwide interest. About 6000 cancer patients have already been treated with carbon beams from the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan. These clinical results have clearly verified the advantages of carbon ions. Heidelberg Ion Therapy Center and Gunma University Heavy Ion Medical Center have been successfully launched. Several new facilities are under commissioning or construction. The beam energy is adjusted to the depth of tumors. It is usually between 140 and 430 MeV/u. Although the beam intensity depends on the irradiation method, it is typically several 10{sup 8} or 10{sup 9} pps. Synchrotrons are only utilized for carbon ion radiotherapy. An ECR ion source supplies multi-charged carbon ions for this requirement. Some other medical applications with ion beams attract developer's interests. For example, the several types of

  15. Commnity Petascale Project for Accelerator Science And Simulation: Advancing Computational Science for Future Accelerators And Accelerator Technologies

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

    Spentzouris, Panagiotis; /Fermilab; Cary, John

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessarymore » accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.« less

  16. 78 FR 2953 - National Cybersecurity Center of Excellence (NCCoE) Secure Exchange of Electronic Health...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-15

    ...-01] National Cybersecurity Center of Excellence (NCCoE) Secure Exchange of Electronic Health... the National Cybersecurity Center of Excellence (NCCoE) in the Secure Exchange of Electronic Health... accelerating the widespread adoption of integrated cybersecurity tools and technologies. The NCCoE will bring...

  17. 76 FR 49645 - National Health Center Week, 2011

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-10

    ... system. Every day, men, women, and children find help at community health centers. These centers lead the... stronger, healthier Nation that drives the work of community health centers and fuels our efforts to...

  18. Testing of a Loop Heat Pipe Subjective to Variable Accelerations. Part 2; Temperature Stability

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Ottenstein, Laura; Kaya, Taril; Rogers, Paul; Hoff, Craig

    2000-01-01

    The effect of accelerating forces on the performance of loop heat pipes (LHP) is of interest and importance to terrestrial and space applications. LHP's are being considered for cooling of military combat vehicles and for spinning spacecraft. In order to investigate the effect of an accelerating force on LHP operation, a miniature LHP was installed on a spin table. Variable accelerating forces were imposed on the LHP by spinning the table at different angular speeds. Several patterns of accelerating forces were applied, i.e. continuous spin at different speeds and periodic spin at different speeds and frequencies. The resulting accelerations ranged from 1.17 g's to 4.7 g's. This paper presents the second part of the experimental study, i.e. the effect of an accelerating force on the LHP operating temperature. It has been known that in stationary tests the LHP operating temperature is a function of the evaporator power and the condenser sink temperature when the compensation temperature is not actively controlled. Results of this test program indicate that any change in the accelerating force will result in a chance in the LHP operating temperature through its influence on the fluid distribution in the evaporator, condenser and compensation chamber. However, the effect is not universal, rather it is a function of other test conditions. A steady, constant acceleration may result in an increase or decrease of the operating temperature, while a periodic spin will lead to a quasi-steady operating temperature over a sufficient time interval. In addition, an accelerating force may lead to temperature hysteresis and changes in the temperature oscillation. In spite of all these effects, the LHP continued to operate without any problems in all tests.

  19. Energy Department Announces National Bioenergy Center

    Science.gov Websites

    Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colo., and Oak Ridge National Laboratories (ORNL) in Oak Ridge, Tenn. will lead the Bioenergy Center. The center will link DOE-funded biomass

  20. Effect of off-center ion substitution in morphotropic lead zirconate titanate composition

    NASA Astrophysics Data System (ADS)

    Bhattarai, Mohan K.; Pavunny, Shojan P.; Instan, Alvaro A.; Scott, James F.; Katiyar, Ram S.

    2017-05-01

    A detailed study of the effect of off-center donor ion (Sc3+) substitution on structural, microstructural, optical, dielectric, electrical, and ferroelectric properties of morphotropic composition of lead zirconate titanate electroceramics with the stoichiometric formula Pb0.85Sc0.10Zr0.53Ti0.47O3 (PSZT) and synthesized using a high energy solid-state reaction technique was carried out. Powder x-ray diffractometry was used to identify the stabilized tetragonal phase (space group P 4 m m ) with considerably reduced tetragonal strain, c /a = 1.005. An analysis of the thermal dependence of the Raman results indicated a smooth displacive (ferroelectric-paraelectric) phase transition as revealed by the observed disappearance of the soft modes A1 (1TO) and A1 (2TO) above 460 K. The dielectric response of Pt/PSZT/Pt metal-ferroelectric-metal capacitors was probed over a wide range of thermal excursions (85-600 K) and ac signal frequencies (102-106 Hz). Thermally activated dynamic and static conduction processes indicate hopping conduction mechanism ( Ea c t ≤ 0.015 eV) and the formation of small polarons caused by the electron and/or hole-lattice (phonon) interaction ( Ea c t ≥ 0.1 eV) at low (100-300 K) and high temperatures (300-600 K), respectively. The reduction in remnant polarization obtained is in good agreement with the largely reduced tetragonal strain observed in this sample, ( Pr ∝ √{c /a -1 } ). DC conduction is dominated by Poole-Frenkel mechanism that assumes a Coulombic attraction between detrapped electrons and positively charged stationary defect species in the polycrystalline matrix.

  1. Intraoperative acceleration measurements to quantify improvement in tremor during deep brain stimulation surgery.

    PubMed

    Shah, Ashesh; Coste, Jérôme; Lemaire, Jean-Jacques; Taub, Ethan; Schüpbach, W M Michael; Pollo, Claudio; Schkommodau, Erik; Guzman, Raphael; Hemm-Ode, Simone

    2017-05-01

    Deep brain stimulation (DBS) surgery is extensively used in the treatment of movement disorders. Nevertheless, methods to evaluate the clinical response during intraoperative stimulation tests to identify the optimal position for the implantation of the chronic DBS lead remain subjective. In this paper, we describe a new, versatile method for quantitative intraoperative evaluation of improvement in tremor with an acceleration sensor that is mounted on the patient's wrist during surgery. At each anatomical test position, the improvement in tremor compared to the initial tremor is estimated on the basis of extracted outcome measures. This method was tested on 15 tremor patients undergoing DBS surgery in two centers. Data from 359 stimulation tests were acquired. Our results suggest that accelerometric evaluation detects tremor changes more sensitively than subjective visual ratings. The effective stimulation current amplitudes identified from the quantitative data (1.1 ± 0.8 mA) are lower than those identified by visual evaluation (1.7 ± 0.8 mA) for similar improvement in tremor. Additionally, if these data had been used to choose the chronic implant position of the DBS lead, 15 of the 26 choices would have been different. These results show that our method of accelerometric evaluation can potentially improve DBS targeting.

  2. Effects of Alfvénic Drift on Diffusive Shock Acceleration at Weak Cluster Shocks

    NASA Astrophysics Data System (ADS)

    Kang, Hyesung; Ryu, Dongsu

    2018-03-01

    Non-detection of γ-ray emission from galaxy clusters has challenged diffusive shock acceleration (DSA) of cosmic-ray (CR) protons at weak collisionless shocks that are expected to form in the intracluster medium. As an effort to address this problem, we here explore possible roles of Alfvén waves self-excited via resonant streaming instability during the CR acceleration at parallel shocks. The mean drift of Alfvén waves may either increase or decrease the scattering center compression ratio, depending on the postshock cross-helicity, leading to either flatter or steeper CR spectra. We first examine such effects at planar shocks, based on the transport of Alfvén waves in the small amplitude limit. For the shock parameters relevant to cluster shocks, Alfvénic drift flattens the CR spectrum slightly, resulting in a small increase of the CR acceleration efficiency, η. We then consider two additional, physically motivated cases: (1) postshock waves are isotropized via MHD and plasma processes across the shock transition, and (2) postshock waves contain only forward waves propagating along with the flow due to a possible gradient of CR pressure behind the shock. In these cases, Alfvénic drift could reduce η by as much as a factor of five for weak cluster shocks. For the canonical parameters adopted here, we suggest η ∼ 10‑4–10‑2 for shocks with sonic Mach number M s ≈ 2–3. The possible reduction of η may help ease the tension between non-detection of γ-rays from galaxy clusters and DSA predictions.

  3. Microgravity Acceleration Measurement System (MAMS) Flight Configuration Verification and Status

    NASA Technical Reports Server (NTRS)

    Wagar, William

    2000-01-01

    The Microgravity Acceleration Measurement System (MAMS) is a precision spaceflight instrument designed to measure and characterize the microgravity environment existing in the US Lab Module of the International Space Station. Both vibratory and quasi-steady triaxial acceleration data are acquired and provided to an Ethernet data link. The MAMS Double Mid-Deck Locker (DMDL) EXPRESS Rack payload meets all the ISS IDD and ICD interface requirements as discussed in the paper which also presents flight configuration illustrations. The overall MAMS sensor and data acquisition performance and verification data are presented in addition to a discussion of the Command and Data Handling features implemented via the ISS, downlink and the GRC Telescience Center displays.

  4. Fabrication and Characterization of Woodpile Structures for Direct Laser Acceleration

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

    McGuinness, C.; Colby, E.; England, R.J.

    2010-08-26

    An eight and nine layer three dimensional photonic crystal with a defect designed specifically for accelerator applications has been fabricated. The structures were fabricated using a combination of nanofabrication techniques, including low pressure chemical vapor deposition, optical lithography, and chemical mechanical polishing. Limits imposed by the optical lithography set the minimum feature size to 400 nm, corresponding to a structure with a bandgap centered at 4.26 {micro}m. Reflection spectroscopy reveal a peak in reflectivity about the predicted region, and good agreement with simulation is shown. The eight and nine layer structures will be aligned and bonded together to form themore » complete seventeen layer woodpile accelerator structure.« less

  5. Shock-wave proton acceleration from a hydrogen gas jet

    NASA Astrophysics Data System (ADS)

    Cook, Nathan; Pogorelsky, Igor; Polyanskiy, Mikhail; Babzien, Marcus; Tresca, Olivier; Maharjan, Chakra; Shkolnikov, Peter; Yakimenko, Vitaly

    2013-04-01

    Typical laser acceleration experiments probe the interaction of intense linearly-polarized solid state laser pulses with dense metal targets. This interaction generates strong electric fields via Transverse Normal Sheath Acceleration and can accelerate protons to high peak energies but with a large thermal spectrum. Recently, the advancement of high pressure amplified CO2 laser technology has allowed for the creation of intense (10^16 Wcm^2) pulses at λ˜10 μm. These pulses may interact with reproducible, high rep. rate gas jet targets and still produce plasmas of critical density (nc˜10^19 cm-3), leading to the transference of laser energy via radiation pressure. This acceleration mode has the advantage of producing narrow energy spectra while scaling well with pulse intensity. We observe the interaction of an intense CO2 laser pulse with an overdense hydrogen gas jet. Using two pulse optical probing in conjunction with interferometry, we are able to obtain density profiles of the plasma. Proton energy spectra are obtained using a magnetic spectrometer and scintillating screen.

  6. Optimized operation of dielectric laser accelerators: Single bunch

    NASA Astrophysics Data System (ADS)

    Hanuka, Adi; Schächter, Levi

    2018-05-01

    We introduce a general approach to determine the optimal charge, efficiency and gradient for laser driven accelerators in a self-consistent way. We propose a way to enhance the operational gradient of dielectric laser accelerators by leverage of beam-loading effect. While the latter may be detrimental from the perspective of the effective gradient experienced by the particles, it can be beneficial as the effective field experienced by the accelerating structure, is weaker. As a result, the constraint imposed by the damage threshold fluence is accordingly weakened and our self-consistent approach predicts permissible gradients of ˜10 GV /m , one order of magnitude higher than previously reported experimental results—with unbunched pulse of electrons. Our approach leads to maximum efficiency to occur for higher gradients as compared with a scenario in which the beam-loading effect on the material is ignored. In any case, maximum gradient does not occur for the same conditions that maximum efficiency does—a trade-off set of parameters is suggested.

  7. Design study of electron cyclotron resonance-ion plasma accelerator for heavy ion cancer therapy.

    PubMed

    Inoue, T; Hattori, T; Sugimoto, S; Sasai, K

    2014-02-01

    Electron Cyclotron Resonance-Ion Plasma Accelerator (ECR-IPAC) device, which theoretically can accelerate multiple charged ions to several hundred MeV with short acceleration length, has been proposed. The acceleration mechanism is based on the combination of two physical principles, plasma electron ion adiabatic ejection (PLEIADE) and Gyromagnetic Autoresonance (GYRAC). In this study, we have designed the proof of principle machine ECR-IPAC device and simulated the electromagnetic field distribution generating in the resonance cavity. ECR-IPAC device consisted of three parts, ECR ion source section, GYRAC section, and PLEIADE section. ECR ion source section and PLEIADE section were designed using several multi-turn solenoid coils and sextupole magnets, and GYRAC section was designed using 10 turns coil. The structure of ECR-IPAC device was the cylindrical shape, and the total length was 1024 mm and the maximum diameter was 580 mm. The magnetic field distribution, which maintains the stable acceleration of plasma, was generated on the acceleration center axis throughout three sections. In addition, the electric field for efficient acceleration of electrons was generated in the resonance cavity by supplying microwave of 2.45 GHz.

  8. Lead poisoning in children.

    PubMed

    Warniment, Crista; Tsang, Katrina; Galazka, Sim S

    2010-03-15

    The prevalence and severity of childhood lead poisoning have been greatly reduced since the removal of lead from paint and gasoline in the 1970s. Despite these efforts, approximately 310,000 U.S. children younger than five years have elevated blood lead levels. Health care professionals should perform targeted screening for lead poisoning in children who are Medicaid-enrolled or -eligible, foreign born, or identified as high risk by the Centers for Disease Control and Prevention (CDC) location-specific recommendations or by a personal risk questionnaire. Venous sampling is the preferred method for measuring blood lead levels, but a carefully collected finger-stick sample is an acceptable alternative. Capillary samples of elevated levels should be confirmed by a venous sample. The CDC recommends that the threshold for follow-up and intervention of lead poisoning be a blood lead level of 10 microg per dL or higher. Recommendations for treatment of elevated blood levels include a thorough environmental investigation, laboratory testing when appropriate, iron supplementation for iron-deficient children, and chelation therapy for blood lead levels of 45 microg per dL or more. Prevention consists of education and avoidance of lead-contaminated products.

  9. Vacuum Plasma Spray Forming of Tungsten Lorentz Force Accelerator Components

    NASA Technical Reports Server (NTRS)

    Zimmerman, Frank R.

    2004-01-01

    The Vacuum Plasma Spray (VPS) Laboratory at NASA's Marshall Space Flight Center, working with the Jet Propulsion Laboratory, has developed and demonstrated a fabrication technique using the VPS process to form anode and cathode sections for a Lorentz force accelerator made from tungsten. Lorentz force accelerators are an attractive form of electric propulsion that provides continuous, high-efficiency propulsion at useful power levels for such applications as orbit transfers or deep space missions. The VPS process is used to deposit refractory metals such as tungsten onto a graphite mandrel of the desired shape. Because tungsten is reactive at high temperatures, it is thermally sprayed in an inert environment where the plasma gun melts and deposits the molten metal powder onto a mandrel. A three-axis robot inside the chamber controls the motion of the plasma spray torch. A graphite mandrel acts as a male mold, forming the required contour and dimensions for the inside surface of the anode or cathode of the accelerator. This paper describes the processing techniques, design considerations, and process development associated with the VPS forming of Lorentz force accelerator components.

  10. Construction comparison of Louisiana's conventional and alternative base courses under accelerated loading : final report.

    DOT National Transportation Integrated Search

    2001-11-01

    This report describes the test results of the first project at the Louisiana Transportation Research Center's Accelerated Loading Facility (ALF). In 1995, 9 test lanes were constructed at the Louisiana Pavement Research Facility in Port Allen. These ...

  11. Acceleration of a ground-state reaction by selective femtosecond-infrared-laser-pulse excitation

    NASA Astrophysics Data System (ADS)

    Stensitzki, Till; Yang, Yang; Kozich, Valeri; Ahmed, Ashour A.; Kössl, Florian; Kühn, Oliver; Heyne, Karsten

    2018-02-01

    Infrared (IR) excitation of vibrations that participate in the reaction coordinate of an otherwise thermally driven chemical reaction are believed to lead to its acceleration. Attempts at the practical realization of this concept have been hampered so far by competing processes leading to sample heating. Here we demonstrate, using femtosecond IR-pump IR-probe experiments, the acceleration of urethane and polyurethane formation due to vibrational excitation of the reactants for 1:1 mixtures of phenylisocyanate and cyclohexanol, and toluene-2,4-diisocyanate and 2,2,2-trichloroethane-1,1-diol, respectively. We measured reaction rate changes upon selective vibrational excitation with negligible heating of the sample and observed an increase of the reaction rate up to 24%. The observation is rationalized using reactant and transition-state structures obtained from quantum chemical calculations. We subsequently used IR-driven reaction acceleration to write a polyurethane square on sample windows using a femtosecond IR pulse.

  12. Piezoelectric particle accelerator

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

    Kemp, Mark A.; Jongewaard, Erik N.; Haase, Andrew A.

    2017-08-29

    A particle accelerator is provided that includes a piezoelectric accelerator element, where the piezoelectric accelerator element includes a hollow cylindrical shape, and an input transducer, where the input transducer is disposed to provide an input signal to the piezoelectric accelerator element, where the input signal induces a mechanical excitation of the piezoelectric accelerator element, where the mechanical excitation is capable of generating a piezoelectric electric field proximal to an axis of the cylindrical shape, where the piezoelectric accelerator is configured to accelerate a charged particle longitudinally along the axis of the cylindrical shape according to the piezoelectric electric field.

  13. Development of a Dielectric-Loaded Accelerator Test Facility Based on an X-Band Magnicon Amplifier

    NASA Astrophysics Data System (ADS)

    Gold, S. H.; Kinkead, A. K.; Gai, W.; Power, J. G.; Konecny, R.; Jing, C.; Tantawi, S. G.; Nantista, C. D.; Hu, Y.; Du, X.; Tang, C.; Lin, Y.; Bruce, R. W.; Bruce, R. L.; Fliflet, A. W.; Lewis, D.

    2006-01-01

    The Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), are developing a dielectric-loaded accelerator (DLA) test facility powered by the 11.424-GHz magnicon amplifier that was developed jointly by NRL and Omega-P, Inc. Thus far, DLA structures developed by ANL have been tested at the NRL Magnicon Facility without injected electrons, including tests of alumina and magnesium calcium titanate structures at gradients up to ˜8 MV/m. The next step is to inject electrons in order to build a compact DLA test accelerator. The Accelerator Laboratory of Tsinghua University in Beijing, China has developed a 5-MeV electron injector for the accelerator, and SLAC is developing a means to combine the two magnicon output arms, and to drive the injector and an accelerator section with separate control of the power ratio and relative phase. Also, RWBruce Associates, working with NRL, is developing a means to join ceramic tubes to produce long accelerating sections using a microwave brazing process. The installation and commissioning of the first dielectric-loaded test accelerator, including injector, DLA structure, and spectrometer, should take place within the next year.

  14. Utilizing GPUs to Accelerate Turbomachinery CFD Codes

    NASA Technical Reports Server (NTRS)

    MacCalla, Weylin; Kulkarni, Sameer

    2016-01-01

    GPU computing has established itself as a way to accelerate parallel codes in the high performance computing world. This work focuses on speeding up APNASA, a legacy CFD code used at NASA Glenn Research Center, while also drawing conclusions about the nature of GPU computing and the requirements to make GPGPU worthwhile on legacy codes. Rewriting and restructuring of the source code was avoided to limit the introduction of new bugs. The code was profiled and investigated for parallelization potential, then OpenACC directives were used to indicate parallel parts of the code. The use of OpenACC directives was not able to reduce the runtime of APNASA on either the NVIDIA Tesla discrete graphics card, or the AMD accelerated processing unit. Additionally, it was found that in order to justify the use of GPGPU, the amount of parallel work being done within a kernel would have to greatly exceed the work being done by any one portion of the APNASA code. It was determined that in order for an application like APNASA to be accelerated on the GPU, it should not be modular in nature, and the parallel portions of the code must contain a large portion of the code's computation time.

  15. Electron dynamics in a plasma focus. [electron acceleration

    NASA Technical Reports Server (NTRS)

    Hohl, F.; Gary, S. P.; Winters, P. A.

    1977-01-01

    Results are presented of a numerical integration of the three-dimensional relativistic equations of motion of electrons subject to given electric and magnetic fields deduced from experiments. Fields due to two different models are investigated. For the first model, the fields are those due to a circular distribution of axial current filaments. As the current filaments collapse toward the axis, large azimuthal magnetic and axial electric fields are induced. These fields effectively heat the electrons to a temperature of approximately 8 keV and accelerate electrons within the radius of the filaments to high axial velocities. Similar results are obtained for the current-reduction phase of focus formation. For the second model, the fields are those due to a uniform current distribution. Both the current-reduction and the compression phases were studied. These is little heating or acceleration of electrons during the compression phase because the electrons are tied to the magnetic field. However, during the current-reduction phase, electrons near the axis are accelerated toward the center electrode and reach energies of 100 keV. A criterion is obtained which limits the runaway electron current to about 400 A.

  16. Operation of polycarbonate projectiles in the ram accelerator

    NASA Astrophysics Data System (ADS)

    Elder, Timothy

    The ram accelerator is a hypervelocity launcher with direct space launch applications in which a sub-caliber projectile, analogous to the center-body of a ramjet engine, flies through fuel and oxidizer that have been premixed in a tube. Shock interactions in the tube ignite the propellant upon entrance of the projectile and the combustion travels with it, creating thrust on the projectile by stabilizing a high pressure region of gas behind it. Conventional ram accelerator projectiles consist of aluminum, magnesium, or titanium nosecones and bodies. An experimental program has been undertaken to determine the performance of polycarbonate projectiles in ram accelerator operation. Experimentation using polycarbonate projectiles has been divided into two series: determining the lower limit for starting velocity (i.e., less than 1100 m/s) and investigating the upper velocity limit. To investigate the influence of body length and starting velocity, a newly developed "combustion gun" was used to launch projectiles to their initial velocities. The combustion gun uses 3-6 m of ram accelerator test section as a breech and 4-6 m of the ram accelerator test section as a launch tube. A fuel-oxidizer mix is combusted in the breech using a spark plug or electric match and bursts a diaphragm, accelerating the ram projectile to its entrance velocity. The combustion gun can be operated at modest fill pressures (20 bar) but can only launch to relatively low velocities (approximately 1000 m/s) without destroying the projectile and obturator upon launch. Projectiles were successfully started at entrance velocities as low as 810 m/s and projectile body lengths as long as 91 mm were used. The tests investigating the upper Mach number limits of polycarbonate projectiles used the conventional single-stage light-gas gun because of its ability to reach higher velocities with a lower acceleration launch. It was determined that polycarbonate projectiles have an upper velocity limit in the

  17. ACCELERATION OF THERMAL PROTONS BY GENERIC PHENOMENOLOGICAL MECHANISMS

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

    Petrosian, Vahé; Kang, Byungwoo, E-mail: vahep@stanford.edu, E-mail: redcrux8@stanford.edu

    2015-11-01

    We investigate heating and acceleration of protons from a thermal gas with a generic diffusion and acceleration model, and subject to Coulomb scattering and energy loss, as was done by Petrosian and East for electrons. As protons gain energy their loss to electrons becomes important. Thus, we need to solve the coupled proton–electron kinetic equation. We numerically solve the coupled Fokker–Planck equations and compute the time evolution of the spectra of both particles. We show that this can lead to a quasi-thermal component plus a high-energy nonthermal tail. We determine the evolution of the nonthermal tail and the quasi-thermal component.more » The results may be used to explore the possibility of inverse bremsstrahlung radiation as a source of hard X-ray emissions from hot sources such as solar flares, accretion disk coronas, and the intracluster medium of galaxy clusters. We find that the emergence of nonthermal protons is accompanied by excessive heating of the entire plasma, unless the turbulence needed for scattering and acceleration is steeper than Kolmogorov and the acceleration parameters, the duration of the acceleration, and/or the initial distributions are significantly fine-tuned. These results severely constrain the feasibility of the nonthermal inverse bremsstrahlung process producing hard X-ray emissions. However, the nonthermal tail may be the seed particles for further re-acceleration to relativistic energies, say by a shock. In the Appendix we present some tests of the integrity of the algorithm used and present a new formula for the energy loss rate due to inelastic proton–proton interactions.« less

  18. Martial arts striking hand peak acceleration, accuracy and consistency.

    PubMed

    Neto, Osmar Pinto; Marzullo, Ana Carolina De Miranda; Bolander, Richard P; Bir, Cynthia A

    2013-01-01

    The goal of this paper was to investigate the possible trade-off between peak hand acceleration and accuracy and consistency of hand strikes performed by martial artists of different training experiences. Ten male martial artists with training experience ranging from one to nine years volunteered to participate in the experiment. Each participant performed 12 maximum effort goal-directed strikes. Hand acceleration during the strikes was obtained using a tri-axial accelerometer block. A pressure sensor matrix was used to determine the accuracy and consistency of the strikes. Accuracy was estimated by the radial distance between the centroid of each subject's 12 strikes and the target, whereas consistency was estimated by the square root of the 12 strikes mean squared distance from their centroid. We found that training experience was significantly correlated to hand peak acceleration prior to impact (r(2)=0.456, p =0.032) and accuracy (r(2)=0. 621, p=0.012). These correlations suggest that more experienced participants exhibited higher hand peak accelerations and at the same time were more accurate. Training experience, however, was not correlated to consistency (r(2)=0.085, p=0.413). Overall, our results suggest that martial arts training may lead practitioners to achieve higher striking hand accelerations with better accuracy and no change in striking consistency.

  19. The effect of a longitudinal density gradient on electron plasma wake field acceleration

    NASA Astrophysics Data System (ADS)

    Tsiklauri, David

    2016-12-01

    Three-dimensional, particle-in-cell, fully electromagnetic simulations of electron plasma wake field acceleration in the blow-out regime are presented. Earlier results are extended by (i) studying the effect of a longitudinal density gradient, (ii) avoiding the use of a co-moving simulation box, (iii) inclusion of ion motion, and (iv) studying fully electromagnetic plasma wake fields. It is established that injecting driving and trailing electron bunches into a positive density gradient of 10-fold increasing density over 10 cm long lithium vapour plasma results in spatially more compact and three times larger, compared with the uniform density case, electric fields (-6.4×1010 V m-1), leading to acceleration of the trailing bunch up to 24.4 GeV (starting from an initial 20.4 GeV), with energy transfer efficiencies from the leading to trailing bunch of 75%. In the uniform density case, a -2.5×1010 V m-1 wake is created leading to acceleration of the trailing bunch up to 22.4 GeV, with energy transfer efficiencies of 65%. It is also established that injecting the electron bunches into a negative density gradient of 10-fold decreasing density over 10 cm long plasma results in spatially more spread and two and a half smaller electric fields (-1.0×1010 V m-1), leading to a weaker acceleration of the trailing bunch up to 21.4 GeV, with energy transfer efficiencies of 45%. Taking ion motions into consideration shows that in the plasma wake ion number density can increase over a few times the background value. It is also shown that transverse electromagnetic fields in a plasma wake are of the same order as the longitudinal (electrostatic) ones.

  20. Pulse Front Tilt and Laser Plasma Acceleration

    NASA Astrophysics Data System (ADS)

    Mittelberger, Daniel; Thévenet, Maxence; Nakamura, Kei; Lehe, Remi; Gonsalves, Anthony; Benedetti, Carlo; Leemans, Wim

    2017-10-01

    Pulse front tilt (PFT) is potentially present in any CPA laser system, but its effects may be overlooked because spatiotemporal pulse characterization is considerably more involved than measuring only spatial or temporal profile. PFT is particularly important for laser plasma accelerators (LPA) because it influences electron beam injection and steering. In this work, experimental results from the BELLA Center will be presented that demonstrate the effect of optical grating misalignment and optical compression, resulting in PFT, on accelerator performance. Theoretical models of laser and electron beam steering will be introduced based on particle-in-cell simulations showing distortion of the plasma wake. Theoretical predictions will be compared with experiments and complimentary simulations, and tolerances on PFT and optical compressor alignment will be developed as a function of LPA performance requirements. This work was supported by the Office of High Energy Physics, Office of Science, US Department of Energy under Contract DE-AC02-05CH11231 and the National Science Foundation under Grant PHY-1415596.

  1. Implications of an Absolute Simultaneity Theory for Cosmology and Universe Acceleration

    PubMed Central

    Kipreos, Edward T.

    2014-01-01

    An alternate Lorentz transformation, Absolute Lorentz Transformation (ALT), has similar kinematics to special relativity yet maintains absolute simultaneity in the context of a preferred reference frame. In this study, it is shown that ALT is compatible with current experiments to test Lorentz invariance only if the proposed preferred reference frame is locally equivalent to the Earth-centered non-rotating inertial reference frame, with the inference that in an ALT framework, preferred reference frames are associated with centers of gravitational mass. Applying this theoretical framework to cosmological data produces a scenario of universal time contraction in the past. In this scenario, past time contraction would be associated with increased levels of blueshifted light emissions from cosmological objects when viewed from our current perspective. The observation that distant Type Ia supernovae are dimmer than predicted by linear Hubble expansion currently provides the most direct evidence for an accelerating universe. Adjusting for the effects of time contraction on a redshift–distance modulus diagram produces a linear distribution of supernovae over the full redshift spectrum that is consistent with a non-accelerating universe. PMID:25536116

  2. Implications of an absolute simultaneity theory for cosmology and universe acceleration.

    PubMed

    Kipreos, Edward T

    2014-01-01

    An alternate Lorentz transformation, Absolute Lorentz Transformation (ALT), has similar kinematics to special relativity yet maintains absolute simultaneity in the context of a preferred reference frame. In this study, it is shown that ALT is compatible with current experiments to test Lorentz invariance only if the proposed preferred reference frame is locally equivalent to the Earth-centered non-rotating inertial reference frame, with the inference that in an ALT framework, preferred reference frames are associated with centers of gravitational mass. Applying this theoretical framework to cosmological data produces a scenario of universal time contraction in the past. In this scenario, past time contraction would be associated with increased levels of blueshifted light emissions from cosmological objects when viewed from our current perspective. The observation that distant Type Ia supernovae are dimmer than predicted by linear Hubble expansion currently provides the most direct evidence for an accelerating universe. Adjusting for the effects of time contraction on a redshift-distance modulus diagram produces a linear distribution of supernovae over the full redshift spectrum that is consistent with a non-accelerating universe.

  3. Sustained Accelerated Idioventricular Rhythm in a Centrifuge-Simulated Suborbital Spaceflight.

    PubMed

    Suresh, Rahul; Blue, Rebecca S; Mathers, Charles; Castleberry, Tarah L; Vanderploeg, James M

    2017-08-01

    Hypergravitational exposures during human centrifugation are known to provoke dysrhythmias, including sinus dysrhythmias/tachycardias, premature atrial/ventricular contractions, and even atrial fibrillations or flutter patterns. However, events are generally short-lived and resolve rapidly after cessation of acceleration. This case report describes a prolonged ectopic ventricular rhythm in response to high G exposure. A previously healthy 30-yr-old man voluntarily participated in centrifuge trials as a part of a larger study, experiencing a total of 7 centrifuge runs over 48 h. Day 1 consisted of two +Gz runs (peak +3.5 Gz, run 2) and two +Gx runs (peak +6.0 Gx, run 4). Day 2 consisted of three runs approximating suborbital spaceflight profiles (combined +Gx and +Gz). Hemodynamic data collected included blood pressure, heart rate, and continuous three-lead electrocardiogram. Following the final acceleration exposure of the last Day 2 run (peak +4.5 Gx and +4.0 Gz combined, resultant +6.0 G), during a period of idle resting centrifuge activity (resultant vector +1.4 G), the subject demonstrated a marked change in his three-lead electrocardiogram from normal sinus rhythm to a wide-complex ectopic ventricular rhythm at a rate of 91-95 bpm, consistent with an accelerated idioventricular rhythm (AIVR). This rhythm was sustained for 2 m, 24 s before reversion to normal sinus. The subject reported no adverse symptoms during this time. While prolonged, the dysrhythmia was asymptomatic and self-limited. AIVR is likely a physiological response to acceleration and can be managed conservatively. Vigilance is needed to ensure that AIVR is correctly distinguished from other, malignant rhythms to avoid inappropriate treatment and negative operational impacts.Suresh R, Blue RS, Mathers C, Castleberry TL, Vanderploeg JM. Sustained accelerated idioventricular rhythm in a centrifuge-simulated suborbital spaceflight. Aerosp Med Hum Perform. 2017; 88(8):789-793.

  4. The Soreq Applied Research Accelerator Facility (SARAF): Overview, research programs and future plans

    NASA Astrophysics Data System (ADS)

    Mardor, Israel; Aviv, Ofer; Avrigeanu, Marilena; Berkovits, Dan; Dahan, Adi; Dickel, Timo; Eliyahu, Ilan; Gai, Moshe; Gavish-Segev, Inbal; Halfon, Shlomi; Hass, Michael; Hirsh, Tsviki; Kaiser, Boaz; Kijel, Daniel; Kreisel, Arik; Mishnayot, Yonatan; Mukul, Ish; Ohayon, Ben; Paul, Michael; Perry, Amichay; Rahangdale, Hitesh; Rodnizki, Jacob; Ron, Guy; Sasson-Zukran, Revital; Shor, Asher; Silverman, Ido; Tessler, Moshe; Vaintraub, Sergey; Weissman, Leo

    2018-05-01

    The Soreq Applied Research Accelerator Facility (SARAF) is under construction in the Soreq Nuclear Research Center at Yavne, Israel. When completed at the beginning of the next decade, SARAF will be a user facility for basic and applied nuclear physics, based on a 40 MeV, 5 mA CW proton/deuteron superconducting linear accelerator. Phase I of SARAF (SARAF-I, 4 MeV, 2 mA CW protons, 5 MeV 1 mA CW deuterons) is already in operation, generating scientific results in several fields of interest. The main ongoing program at SARAF-I is the production of 30 keV neutrons and measurement of Maxwellian Averaged Cross Sections (MACS), important for the astrophysical s-process. The world leading Maxwellian epithermal neutron yield at SARAF-I (5 × 10^{10} epithermal neutrons/s), generated by a novel Liquid-Lithium Target (LiLiT), enables improved precision of known MACSs, and new measurements of low-abundance and radioactive isotopes. Research plans for SARAF-II span several disciplines: precision studies of beyond-Standard-Model effects by trapping light exotic radioisotopes, such as 6He, 8Li and 18, 19, 23Ne, in unprecedented amounts (including meaningful studies already at SARAF-I); extended nuclear astrophysics research with higher energy neutrons, including generation and studies of exotic neutron-rich isotopes relevant to the rapid (r-) process; nuclear structure of exotic isotopes; high energy neutron cross sections for basic nuclear physics and material science research, including neutron induced radiation damage; neutron based imaging and therapy; and novel radiopharmaceuticals development and production. In this paper we present a technical overview of SARAF-I and II, including a description of the accelerator and its irradiation targets; a survey of existing research programs at SARAF-I; and the research potential at the completed facility (SARAF-II).

  5. Method for Monitoring of Neutron Fields near High-Energy Accelerators

    NASA Astrophysics Data System (ADS)

    Beskrovnaia, L. G.; Guseva, S. V.; Timoshenko, G. N.

    2018-05-01

    The monitoring of neutron radiation from high-energy accelerators cannot fully rely on the standard dosimeters and radiometers manufactured in Russia, since these are sensitive only to neutrons with energies below some 10 MeV. This is because neutrons of higher energies can significantly contribute to the personnel doses both close to the accelerator shield and in the neutron multiscattered field around the shield. In this paper, we propose to measure the ambient neutron dose in energy range 10-2 MeV to 1 GeV with a device consisting of two polyethylene balls with diameters of 3 and 10 in. housing slow-neutron detectors. The larger ball also comprises a lead converter (10'' + Pb). This device can be implemented in zonal radiation monitoring in the near-accelerator area.

  6. Source-to-accelerator quadrupole matching section for a compact linear accelerator

    NASA Astrophysics Data System (ADS)

    Seidl, P. A.; Persaud, A.; Ghiorso, W.; Ji, Q.; Waldron, W. L.; Lal, A.; Vinayakumar, K. B.; Schenkel, T.

    2018-05-01

    Recently, we presented a new approach for a compact radio-frequency (RF) accelerator structure and demonstrated the functionality of the individual components: acceleration units and focusing elements. In this paper, we combine these units to form a working accelerator structure: a matching section between the ion source extraction grids and the RF-acceleration unit and electrostatic focusing quadrupoles between successive acceleration units. The matching section consists of six electrostatic quadrupoles (ESQs) fabricated using 3D-printing techniques. The matching section enables us to capture more beam current and to match the beam envelope to conditions for stable transport in an acceleration lattice. We present data from an integrated accelerator consisting of the source, matching section, and an ESQ doublet sandwiched between two RF-acceleration units.

  7. Flow-accelerated corrosion 2016 international conference

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Shipkov, A. A.

    2017-05-01

    The paper discusses materials and results of the most representative world forum on the problems of flow-accelerated metal corrosion in power engineering—Flow-Accelerated Corrosion (FAC) 2016, the international conference, which was held in Lille (France) from May 23 through May 27, 2016, sponsored by EdF-DTG with the support of the International Atomic Energy Agency (IAEA) and the World Association of Nuclear Operators (WANO). The information on major themes of reports and materials of the exhibition arranged within the framework of the congress is presented. The statistics on operation time and intensity of FAC wall thinning of NPP pipelines and equipment in the world is set out. The paper describes typical examples of flow-accelerated corrosion damage of condensate-feed and wet-steam pipeline components of nuclear and thermal power plants that caused forced shutdowns or accidents. The importance of research projects on the problem of flow-accelerated metal corrosion of nuclear power units coordinated by the IAEA with the participation of leading experts in this field from around the world is considered. The reports presented at the conference considered issues of implementation of an FAC mechanism in single- and two-phase flows, the impact of hydrodynamic and water-chemical factors, the chemical composition of the metal, and other parameters on the intensity and location of FAC wall thinning localized areas in pipeline components and power equipment. Features and patterns of local and general FAC leading to local metal thinning and contamination of the working environment with ferriferous compounds are considered. Main trends of modern practices preventing FAC wear of NPP pipelines and equipment are defined. An increasing role of computer codes for the assessment and prediction of FAC rate, as well as software systems of support of the NPP personnel for the inspection planning and prevention of FAC wall thinning of equipment operating in singleand two

  8. Convectively driven decadal zonal accelerations in Earth's fluid core

    NASA Astrophysics Data System (ADS)

    More, Colin; Dumberry, Mathieu

    2018-04-01

    Azimuthal accelerations of cylindrical surfaces co-axial with the rotation axis have been inferred to exist in Earth's fluid core on the basis of magnetic field observations and changes in the length-of-day. These accelerations have a typical timescale of decades. However, the physical mechanism causing the accelerations is not well understood. Scaling arguments suggest that the leading order torque averaged over cylindrical surfaces should arise from the Lorentz force. Decadal fluctuations in the magnetic field inside the core, driven by convective flows, could then force decadal changes in the Lorentz torque and generate zonal accelerations. We test this hypothesis by constructing a quasi-geostrophic model of magnetoconvection, with thermally driven flows perturbing a steady, imposed background magnetic field. We show that when the Alfvén number in our model is similar to that in Earth's fluid core, temporal fluctuations in the torque balance are dominated by the Lorentz torque, with the latter generating mean zonal accelerations. Our model reproduces both fast, free Alfvén waves and slow, forced accelerations, with ratios of relative strength and relative timescale similar to those inferred for the Earth's core. The temporal changes in the magnetic field which drive the time-varying Lorentz torque are produced by the underlying convective flows, shearing and advecting the magnetic field on a timescale associated with convective eddies. Our results support the hypothesis that temporal changes in the magnetic field deep inside Earth's fluid core drive the observed decadal zonal accelerations of cylindrical surfaces through the Lorentz torque.

  9. Harnessing person-generated health data to accelerate patient-centered outcomes research: the Crohn's and Colitis Foundation of America PCORnet Patient Powered Research Network (CCFA Partners).

    PubMed

    Chung, Arlene E; Sandler, Robert S; Long, Millie D; Ahrens, Sean; Burris, Jessica L; Martin, Christopher F; Anton, Kristen; Robb, Amber; Caruso, Thomas P; Jaeger, Elizabeth L; Chen, Wenli; Clark, Marshall; Myers, Kelly; Dobes, Angela; Kappelman, Michael D

    2016-05-01

    The Crohn's and Colitis Foundation of America Partners Patient-Powered Research Network (PPRN) seeks to advance and accelerate comparative effectiveness and translational research in inflammatory bowel diseases (IBDs). Our IBD-focused PCORnet PPRN has been designed to overcome the major obstacles that have limited patient-centered outcomes research in IBD by providing the technical infrastructure, patient governance, and patient-driven functionality needed to: 1) identify, prioritize, and undertake a patient-centered research agenda through sharing person-generated health data; 2) develop and test patient and provider-focused tools that utilize individual patient data to improve health behaviors and inform health care decisions and, ultimately, outcomes; and 3) rapidly disseminate new knowledge to patients, enabling them to improve their health. The Crohn's and Colitis Foundation of America Partners PPRN has fostered the development of a community of citizen scientists in IBD; created a portal that will recruit, retain, and engage members and encourage partnerships with external scientists; and produced an efficient infrastructure for identifying, screening, and contacting network members for participation in research. © The Author 2016. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  10. Fermilab | Tritium at Fermilab | Frequently asked questions

    Science.gov Websites

    computing Quantum initiatives Research and development Key discoveries Benefits of particle physics Particle Accelerators Leading accelerator technology Accelerator complex Illinois Accelerator Research Center Fermilab questions about tritium Tritium in surface water Indian Creek Kress Creek Ferry Creek Tritium in sanitary

  11. Electron bulk acceleration and thermalization at Earth's quasi-perpendicular bow shock

    NASA Astrophysics Data System (ADS)

    Chen, L.-J.; Wang, S.; Wilson, L. B., III; Schwartz, S. J.; Bessho, N.; Moore, T. E.; Gershman, D. J.; Giles, B. L.; Malaspina, D. M.; Wilder, F. D.; Ergun, R. E.; Hesse, M.; Lai, H.; Russell, C. T.; Strangeway, R. J.; Torbert, R. B.; Vinas, A. F.-; Burch, J. L.; Lee, S.; Pollock, C.; Dorelli, J.; Paterson, W. R.; Ahmadi, N.; Goodrich, K. A.; Lavraud, B.; Le Contel, O.; Khotyaintsev, Yu. V.; Lindqvist, P.-A.; Boardsen, S.; Wei, H.; Le, A.; Avanov, L. A.

    2018-05-01

    Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating.

  12. Study of the transverse beam motion in the DARHT Phase II accelerator

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

    Chen, Yu-Jiuan; Fawley, W M; Houck, T L

    1998-08-20

    The accelerator for the second-axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility will accelerate a 4-kA, 3-MeV, 2--µs long electron current pulse to 20 MeV. The energy variation of the beam within the flat-top portion of the current pulse is (plus or equal to) 0.5%. The performance of the DARHT Phase II radiographic machine requires the transverse beam motion to be much less than the beam spot size which is about 1.5 mm diameter on the x-ray converter. In general, the leading causes of the transverse beam motion in an accelerator are the beam breakup instability (BBU) andmore » the corkscrew motion. We have modeled the transverse beam motion in the DARHT Phase II accelerator with various magnetic tunes and accelerator cell configurations by using the BREAKUP code. The predicted sensitivity of corkscrew motion and BBU growth to different tuning algorithms will be presented.« less

  13. Equivalent-Groups versus Single-Group Equating Designs for the Accelerated CAT-ASVAB (Computerized Adaptive Test-Armed Services Vocational Aptitude Battery) Project.

    DTIC Science & Technology

    1987-01-01

    DESIGNS FOR THE ACCELERATED CAT -ASVAB * PROJECT Peter H. Stoloff DTIC’- , " SELECTE -NOV 2 3 987 A Division of Hudson Institute CENTER FOR NAVAL ANALYSES...65153M C0031 SI TITLE (Include Security Classification) Equivalent-Groups Versus Single-Group Equating Designs For The Accelerated CAT -ASVAB Project...GROUP ACAP (Accelerated CAT -ASVAB Program), Aptitude tests, ASVAB (Armed 05 10 Services Vocational Aptitude Battery), CAT (Computerized Adaptive Test

  14. Measurement Challenges at Low Blood Lead Levels.

    PubMed

    Caldwell, Kathleen L; Cheng, Po-Yung; Jarrett, Jeffery M; Makhmudov, Amir; Vance, Kathryn; Ward, Cynthia D; Jones, Robert L; Mortensen, Mary E

    2017-08-01

    In 2012, the Centers for Disease Control and Prevention (CDC) adopted its Advisory Committee on Childhood Lead Poisoning Prevention recommendation to use a population-based reference value to identify children and environments associated with lead hazards. The current reference value of 5 μg/dL is calculated as the 97.5th percentile of the distribution of blood lead levels (BLLs) in children 1 to 5 years old from 2007 to 2010 NHANES data. We calculated and updated selected percentiles, including the 97.5th percentile, by using NHANES 2011 to 2014 blood lead data and examined demographic characteristics of children whose blood lead was ≥90th percentile value. The 97.5th percentile BLL of 3.48 µg/dL highlighted analytical laboratory and clinical interpretation challenges of blood lead measurements ≤5 μg/dL. Review of 5 years of results for target blood lead values <11 µg/dL for US clinical laboratories participating in the CDC's voluntary Lead and Multi-Element Proficiency quality assurance program showed 40% unable to quantify and reported a nondetectable result at a target blood lead value of 1.48 µg/dL, compared with 5.5% at a target BLL of 4.60 µg/dL. We describe actions taken at the CDC's Environmental Health Laboratory in the National Center for Environmental Health, which measures blood lead for NHANES, to improve analytical accuracy and precision and to reduce external lead contamination during blood collection and analysis. Copyright © 2017 by the American Academy of Pediatrics.

  15. Electron acceleration and radiation signatures in loop coronal transients

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Gergely, T. E.; Papadopoulos, K.

    1982-01-01

    It is proposed that in loop coronal transients an erupting loop moves away from the solar surface, with a velocity exceeding the local Alfven speed, pushing against the overlying magnetic fields and driving a shock in the front of the moving part of the loop. Lower hybrid waves are excited at the shock front and propagate radially toward the center of the loop with phase velocity along the magnetic field that exceeds the thermal velocity. The lower hybrid waves stochastically accelerate the tail of the electron distribution inside the loop. The manner in which the accelerated electrons are trapped in the moving loop are discussed, and their radiation signature is estimated. It is suggested that plasma radiation can explain the power observed in stationary and moving type IV bursts.

  16. Accelerator-driven Medical Sterilization to Replace Co-60 Sources

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

    Kroc, Thomas K.; Thangaraj, Jayakar C.T.; Penning, Richard T.

    This report documents the results of a study prepared at the request of the Office of Radiological Security of the National Nuclear Security Administration (NNSA), as part of the Domestic Protect and Reduce mission by the Illinois Accelerator Research Center (IARC) of Fermi National Accelerator Laboratory. The study included a literature survey of over 80 relevant documents and articles including industry standards, regulatory documents, technical papers, a court case, previous task force reports and industry white papers. The team also conducted interviews or had conversations with over 40 individuals representing over a dozen organizations over the course of its 10-monthmore » program. This report summarizes our findings, addresses the specific questions posed to us by NNSA, and concludes with a list of actionable recommendations.« less

  17. Leading Antibacterial Laboratory Research by Integrating Conventional and Innovative Approaches: The Laboratory Center of the Antibacterial Resistance Leadership Group.

    PubMed

    Manca, Claudia; Hill, Carol; Hujer, Andrea M; Patel, Robin; Evans, Scott R; Bonomo, Robert A; Kreiswirth, Barry N

    2017-03-15

    The Antibacterial Resistance Leadership Group (ARLG) Laboratory Center (LC) leads the evaluation, development, and implementation of laboratory-based research by providing scientific leadership and supporting standard/specialized laboratory services. The LC has developed a physical biorepository and a virtual biorepository. The physical biorepository contains bacterial isolates from ARLG-funded studies located in a centralized laboratory and they are available to ARLG investigators. The Web-based virtual biorepository strain catalogue includes well-characterized gram-positive and gram-negative bacterial strains published by ARLG investigators. The LC, in collaboration with the ARLG Leadership and Operations Center, developed procedures for review and approval of strain requests, guidance during the selection process, and for shipping strains from the distributing laboratories to the requesting investigators. ARLG strains and scientific and/or technical guidance have been provided to basic research laboratories and diagnostic companies for research and development, facilitating collaboration between diagnostic companies and the ARLG Master Protocol for Evaluating Multiple Infection Diagnostics (MASTERMIND) initiative for evaluation of multiple diagnostic devices from a single patient sampling event. In addition, the LC has completed several laboratory-based studies designed to help evaluate new rapid molecular diagnostics by developing, testing, and applying a MASTERMIND approach using purified bacterial strains. In collaboration with the ARLG's Statistical and Data Management Center (SDMC), the LC has developed novel analytical strategies that integrate microbiologic and genetic data for improved and accurate identification of antimicrobial resistance. These novel approaches will aid in the design of future ARLG studies and help correlate pathogenic markers with clinical outcomes. The LC's accomplishments are the result of a successful collaboration with the ARLG

  18. Vortex leading edge flap assembly for supersonic airplanes

    NASA Technical Reports Server (NTRS)

    Rudolph, Peter K. C. (Inventor)

    1997-01-01

    A leading edge flap (16) for supersonic transport airplanes is disclosed. In its stowed position, the leading edge flap forms the lower surface of the wing leading edge up to the horizontal center of the leading edge radius. For low speed operation, the vortex leading edge flap moves forward and rotates down. The upward curve of the flap leading edge triggers flow separation on the flap and rotational flow on the upper surface of the flap (vortex). The rounded shape of the upper fixed leading edge provides the conditions for a controlled reattachment of the flow on the upper wing surface and therefore a stable vortex. The vortex generates lift and a nose-up pitching moment. This improves maximum lift at low speed, reduces attitude for a given lift coefficient and improves lift to drag ratio. The mechanism (27) to move the vortex flap consists of two spanwise supports (24) with two diverging straight tracks (64 and 68) each and a screw drive mechanism (62) in the center of the flap panel (29). The flap motion is essentially normal to the airloads and therefore requires only low actuation forces.

  19. NWSC nickel cadmium spacecraft cell accelerated life test program data analysis

    NASA Technical Reports Server (NTRS)

    Lander, J.

    1980-01-01

    An analysis of the data leading to a proposed accelerated life test scheme to test a nickel cadmium cell under spacecraft usage conditions is described. The amount and concentration of electrolyte and the amount of precharge in the cell are discussed in relation to the design of the cell and the accelerated test design. A failure analysis of the cell is summarized. The analysis included such environmental test variables as the depth of discharge, the temperature, the amount of recharge and the charge and discharge rate.

  20. Issues faced by community health centers.

    PubMed

    Grover, Jane

    2009-05-01

    Federally qualified health centers face numerous issues with regard to marketplace competition, staffing, and reimbursement streams that assure financial viability. Positioning the dental department of a health center to a high community profile strengthens the health center in professional educational development leading to a pipeline of workforce members, effective dental directors, and innovative fund-raising. A new dental team member developed by the American Dental Association can be utilized in health centers to make all traditional auxiliaries more productive.

  1. Cancellation of residual spacecraft accelerations for zero-G space physics experiments

    NASA Technical Reports Server (NTRS)

    Stephens, J. B.

    1977-01-01

    The Drop Dynamics Module houses an acoustic positioning system which counteracts the effects of small accelerations of a spacecraft and thus allows long-term study of free-floating materials such as liquid drops. The acoustic positioning system provides an acoustic 'well' in the center of the experiment chamber. Data collection is by cinematographic photography. The module subsystems are discussed.

  2. Present status of Accelerator-Based BNCT

    PubMed Central

    Kreiner, Andres Juan; Bergueiro, Javier; Cartelli, Daniel; Baldo, Matias; Castell, Walter; Asoia, Javier Gomez; Padulo, Javier; Suárez Sandín, Juan Carlos; Igarzabal, Marcelo; Erhardt, Julian; Mercuri, Daniel; Valda, Alejandro A.; Minsky, Daniel M.; Debray, Mario E.; Somacal, Hector R.; Capoulat, María Eugenia; Herrera, María S.; del Grosso, Mariela F.; Gagetti, Leonardo; Anzorena, Manuel Suarez; Canepa, Nicolas; Real, Nicolas; Gun, Marcelo; Tacca, Hernán

    2016-01-01

    Aim This work aims at giving an updated report of the worldwide status of Accelerator-Based BNCT (AB-BNCT). Background There is a generalized perception that the availability of accelerators installed in hospitals, as neutron sources, may be crucial for the advancement of BNCT. Accordingly, in recent years a significant effort has started to develop such machines. Materials and methods A variety of possible charged-particle induced nuclear reactions and the characteristics of the resulting neutron spectra are discussed along with the worldwide activity in suitable accelerator development. Results Endothermic 7Li(p,n)7Be and 9Be(p,n)9B and exothermic 9Be(d,n)10B are compared. In addition to having much better thermo-mechanical properties than Li, Be as a target leads to stable products. This is a significant advantage for a hospital-based facility. 9Be(p,n)9B needs at least 4–5 MeV bombarding energy to have a sufficient yield, while 9Be(d,n)10B can be utilized at about 1.4 MeV, implying the smallest possible accelerator. This reaction operating with a thin target can produce a sufficiently soft spectrum to be viable for AB-BNCT. The machines considered are electrostatic single ended or tandem accelerators or radiofrequency quadrupoles plus drift tube Linacs. Conclusions 7Li(p,n)7Be provides one of the best solutions for the production of epithermal neutron beams for deep-seated tumors. However, a Li-based target poses significant technological challenges. Hence, Be has been considered as an alternative target, both in combination with (p,n) and (d,n) reactions. 9Be(d,n)10B at 1.4 MeV, with a thin target has been shown to be a realistic option for the treatment of deep-seated lesions. PMID:26933390

  3. Present status of Accelerator-Based BNCT.

    PubMed

    Kreiner, Andres Juan; Bergueiro, Javier; Cartelli, Daniel; Baldo, Matias; Castell, Walter; Asoia, Javier Gomez; Padulo, Javier; Suárez Sandín, Juan Carlos; Igarzabal, Marcelo; Erhardt, Julian; Mercuri, Daniel; Valda, Alejandro A; Minsky, Daniel M; Debray, Mario E; Somacal, Hector R; Capoulat, María Eugenia; Herrera, María S; Del Grosso, Mariela F; Gagetti, Leonardo; Anzorena, Manuel Suarez; Canepa, Nicolas; Real, Nicolas; Gun, Marcelo; Tacca, Hernán

    2016-01-01

    This work aims at giving an updated report of the worldwide status of Accelerator-Based BNCT (AB-BNCT). There is a generalized perception that the availability of accelerators installed in hospitals, as neutron sources, may be crucial for the advancement of BNCT. Accordingly, in recent years a significant effort has started to develop such machines. A variety of possible charged-particle induced nuclear reactions and the characteristics of the resulting neutron spectra are discussed along with the worldwide activity in suitable accelerator development. Endothermic (7)Li(p,n)(7)Be and (9)Be(p,n)(9)B and exothermic (9)Be(d,n)(10)B are compared. In addition to having much better thermo-mechanical properties than Li, Be as a target leads to stable products. This is a significant advantage for a hospital-based facility. (9)Be(p,n)(9)B needs at least 4-5 MeV bombarding energy to have a sufficient yield, while (9)Be(d,n)(10)B can be utilized at about 1.4 MeV, implying the smallest possible accelerator. This reaction operating with a thin target can produce a sufficiently soft spectrum to be viable for AB-BNCT. The machines considered are electrostatic single ended or tandem accelerators or radiofrequency quadrupoles plus drift tube Linacs. (7)Li(p,n)(7)Be provides one of the best solutions for the production of epithermal neutron beams for deep-seated tumors. However, a Li-based target poses significant technological challenges. Hence, Be has been considered as an alternative target, both in combination with (p,n) and (d,n) reactions. (9)Be(d,n)(10)B at 1.4 MeV, with a thin target has been shown to be a realistic option for the treatment of deep-seated lesions.

  4. Resonant ion acceleration by plasma jets: Effects of jet breaking and the magnetic-field curvature.

    PubMed

    Artemyev, A V; Vasiliev, A A

    2015-05-01

    In this paper we consider resonant ion acceleration by a plasma jet originating from the magnetic reconnection region. Such jets propagate in the background magnetic field with significantly curved magnetic-field lines. Decoupling of ion and electron motions at the leading edge of the jet results in generation of strong electrostatic fields. Ions can be trapped by this field and get accelerated along the jet front. This mechanism of resonant acceleration resembles surfing acceleration of charged particles at a shock wave. To describe resonant acceleration of ions, we use adiabatic theory of resonant phenomena. We show that particle motion along the curved field lines significantly influences the acceleration rate. The maximum gain of energy is determined by the particle's escape from the system due to this motion. Applications of the proposed mechanism to charged-particle acceleration in the planetary magnetospheres and the solar corona are discussed.

  5. [Projects to accelerate the practical use of innovative medical devices to collaborate with TWIns, Center for Advanced Biomedical Sciences, Waseda University and School of Engineering, The University of Tokyo].

    PubMed

    Niimi, Shingo; Umezu, Mitsuo; Iseki, Hiroshi; Harada, Hiroshi Kasanuki Noboru; Mitsuishi, Mamoru; Kitamori, Takehiko; Tei, Yuichi; Nakaoka, Ryusuke; Haishima, Yuji

    2014-01-01

    Division of Medical Devices has been conducting the projects to accelerate the practical use of innovative medical devices to collaborate with TWIns, Center for Advanced Biomedical Sciences, Waseda University and School of Engineering, The University of Tokyo. The TWIns has been studying to aim at establishment of preclinical evaluation methods by "Engineering Based Medicine", and established Regulatory Science Institute for Medical Devices. School of Engineering, The University of Tokyo has been studying to aim at establishment of assessment methodology for innovative minimally invasive therapeutic devices, materials, and nanobio diagnostic devices. This report reviews the exchanges of personnel, the implement systems and the research progress of these projects.

  6. Accelerating Coagulation in Traumatic Injuries Using Inorganic Polyphosphate-Coated Silica Nanoparticles in a Swine (Sus scrofa) Model

    DTIC Science & Technology

    2018-03-13

    all information . Use additional pages if necessary.) PROTOCOL #: FDG20160012A DATE: 13 March 2018 PROTOCOL TITLE: Accelerating Coagulation...Investigator Attachments: Attachment 1: Defense Technical Information Center (DTIC) Abstract Submission (Mandatory) 4 FDG20160012A...Attachment 1 Defense Technical Information Center (DTIC) Abstract Submission This abstract requires a brief (no more than 200 words) factual summary of the

  7. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  8. Methods for extracting aerodynamic accelerations from Orbiter High Resolution Accelerometer Package flight data

    NASA Technical Reports Server (NTRS)

    Thompson, J. M.; Russell, J. W.; Blanchard, R. C.

    1987-01-01

    This report presents a process for extracting the aerodynamic accelerations of the Shuttle Orbiter Vehicle from the High Resolution Accelerometer Package (HiRAP) flight data during reentry. The methods for obtaining low-level aerodynamic accelerations, principally in the rarefied flow regime, are applied to 10 Orbiter flights. The extraction process is presented using data obtained from Space Transportation System Flight 32 (Mission 61-C) as a typical example. This process involves correcting the HiRAP measurements for the effects of temperature bias and instrument offset from the Orbiter center of gravity, and removing acceleration data during times they are affected by thruster firings. The corrected data are then made continuous and smooth and are further enhanced by refining the temperature bias correction and removing effects of the auxiliary power unit actuation. The resulting data are the current best estimate of the Orbiter aerodynamic accelerations during reentry and will be used for further analyses of the Orbiter aerodynamics and the upper atmosphere characteristics.

  9. Accelerators for society: succession of European infrastructural projects: CARE, EuCARD, TIARA, EuCARD2

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard S.

    2013-10-01

    Accelerator science and technology is one of a key enablers of the developments in the particle physic, photon physics and also applications in medicine and industry. The paper presents a digest of the research results in the domain of accelerator science and technology in Europe, shown during the realization of CARE (Coordinated Accelerator R&D), EuCARD (European Coordination of Accelerator R&D) and during the national annual review meeting of the TIARA - Test Infrastructure of European Research Area in Accelerator R&D. The European projects on accelerator technology started in 2003 with CARE. TIARA is an European Collaboration of Accelerator Technology, which by running research projects, technical, networks and infrastructural has a duty to integrate the research and technical communities and infrastructures in the global scale of Europe. The Collaboration gathers all research centers with large accelerator infrastructures. Other ones, like universities, are affiliated as associate members. TIARA-PP (preparatory phase) is an European infrastructural project run by this Consortium and realized inside EU-FP7. The paper presents a general overview of CARE, EuCARD and especially TIARA activities, with an introduction containing a portrait of contemporary accelerator technology and a digest of its applications in modern society. CARE, EuCARD and TIARA activities integrated the European accelerator community in a very effective way. These projects are expected very much to be continued.

  10. Wind Energy at NREL's National Wind Technology Center

    ScienceCinema

    None

    2017-12-09

    It is a pure, plentiful natural resource. Right now wind is in high demand and it holds the potential to transform the way we power our homes and businesses. NREL is at the forefront of wind energy research and development. NREL's National Wind Technology Center (NWTC) is a world-class facility dedicated to accelerating and deploying wind technology.

  11. Mass discrepancy-acceleration relation: A universal maximum dark matter acceleration and implications for the ultralight scalar dark matter model

    NASA Astrophysics Data System (ADS)

    Ureña-López, L. Arturo; Robles, Victor H.; Matos, T.

    2017-08-01

    Recent analysis of the rotation curves of a large sample of galaxies with very diverse stellar properties reveals a relation between the radial acceleration purely due to the baryonic matter and the one inferred directly from the observed rotation curves. Assuming the dark matter (DM) exists, this acceleration relation is tantamount to an acceleration relation between DM and baryons. This leads us to a universal maximum acceleration for all halos. Using the latter in DM profiles that predict inner cores implies that the central surface density μDM=ρsrs must be a universal constant, as suggested by previous studies of selected galaxies, revealing a strong correlation between the density ρs and scale rs parameters in each profile. We then explore the consequences of the constancy of μDM in the context of the ultralight scalar field dark matter model (SFDM). We find that for this model μDM=648 M⊙ pc-2 and that the so-called WaveDM soliton profile should be a universal feature of the DM halos. Comparing with the data from the Milky Way and Andromeda satellites, we find that they are all consistent with a boson mass of the scalar field particle of the order of 10-21 eV /c2, which puts the SFDM model in agreement with recent cosmological constraints.

  12. Accelerations in Flight

    NASA Technical Reports Server (NTRS)

    Doolittle, J H

    1925-01-01

    This work on accelerometry was done at McCook Field for the purpose of continuing the work done by other investigators and obtaining the accelerations which occur when a high-speed pursuit airplane is subjected to the more common maneuvers. The accelerations obtained in suddenly pulling out of a dive with well-balanced elevators are shown to be within 3 or 4 per cent of the theoretically possible accelerations. The maximum acceleration which a pilot can withstand depends upon the length of time the acceleration is continued. It is shown that he experiences no difficulty under the instantaneous accelerations as high as 7.8 G., but when under accelerations in excess of 4.5 G., continued for several seconds, he quickly loses his faculties.

  13. Poor recovery from a pulmonary exacerbation does not lead to accelerated FEV1 decline.

    PubMed

    Sanders, Don B; Li, Zhanhai; Zhao, Qianqian; Farrell, Philip M

    2017-07-29

    Patients with CF treated for pulmonary exacerbations (PEx) may experience faster subsequent declines in FEV 1 . Additionally, incomplete recovery to baseline FEV 1 occurs frequently following PEx treatment. Whether accelerated declines in FEV 1 are preceded by poor PEx recovery has not been studied. Using 2004 to 2011 CF Foundation Patient Registry data, we randomly selected one PEx among patients ≥6years of age with no organ transplantations, ≥12months of data before and after the PEx, and ≥1 FEV 1 recorded within the 6months before and 3months after the PEx. We defined poor PEx recovery as the best FEV 1 in the 3months after the PEx <90% of the best FEV 1 in the 6months before the PEx. We calculated mean (95% CI) hazard ratios (HR) of having >5% predicted/year FEV 1 decline and poor PEx recovery using multi-state Markov models. From 13,954 PEx, FEV 1 declines of >5% predicted/year were more likely to precede poor spirometric recovery, HR 1.17 (1.08, 1.26), in Markov models adjusted for age and sex. Non-Responders were less likely to have a subsequent fast FEV 1 decline, HR 0.41 (0.37, 0.46), than patients who recovered to >90% of baseline FEV 1 following PEx treatment. Accelerated declines in FEV 1 are more likely to precede a PEx with poor recovery than to occur in the following year. Preventing or halting declines in FEV 1 may also have the benefit of preventing PEx episodes. Copyright © 2017 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

  14. Annular arc accelerator shock tube

    NASA Technical Reports Server (NTRS)

    Leibowitz, L. P. (Inventor)

    1976-01-01

    An annular arc accelerator shock tube employs a cold gas driver to flow a stream of gas from an expansion section through a high voltage electrode section to a test section, thus driving a shock wave in front of it. A glow discharge detects the shock wave and actuates a trigger generator which in turn fires spark-gap switches to discharge a bank of capacitors across a centered cathode and an annular anode in tandem electrode sections. The initial shock wave passes through the anode section from the cathode section thereby depositing energy into the flow gas without the necessity of any diaphragm opening in the gas flow from the expansion section through the electrode sections.

  15. Trunk acceleration for neuroprosthetic control of standing: a pilot study.

    PubMed

    Nataraj, Raviraj; Audu, Musa L; Kirsch, Robert F; Triolo, Ronald J

    2012-02-01

    This pilot study investigated the potential of using trunk acceleration feedback control of center of pressure (COP) against postural disturbances with a standing neuroprosthesis following paralysis. Artificial neural networks (ANNs) were trained to use three-dimensional trunk acceleration as input to predict changes in COP for able-bodied subjects undergoing perturbations during bipedal stance. Correlation coefficients between ANN predictions and actual COP ranged from 0.67 to 0.77. An ANN trained across all subject-normalized data was used to drive feedback control of ankle muscle excitation levels for a computer model representing a standing neuroprosthesis user. Feedback control reduced average upper-body loading during perturbation onset and recovery by 42% and peak loading by 29% compared with optimal, constant excitation.

  16. The ram accelerator - A chemically driven mass launcher

    NASA Technical Reports Server (NTRS)

    Kaloupis, P.; Bruckner, A. P.

    1988-01-01

    The ram accelerator, a chemically propelled mass driver, is presented as a viable new approach for directly launching acceleration-insensitive payloads into low earth orbit. The propulsion principle is similar to that of a conventional air-breathing ramjet. The cargo vehicle resembles the center-body of a ramjet and travels through a tube filled with a pre-mixed fuel and oxidizer mixture. The launch tube acts as the outer cowling of the ramjet and the combustion process travels with the vehicle. Two drive modes of the ram accelerator propulsion system are described, which when used in sequence are capable of accelerating the vehicle to as high as 10 km/sec. The requirements are examined for placing a 2000 kg vehicle into a 500 km orbit with a minimum of on-board rocket propellant for circularization maneuvers. It is shown that aerodynamic heating during atmospheric transit results in very little ablation of the nose. An indirect orbital insertion scenario is selected, utilizing a three step maneuver consisting of two burns and aerobraking. An on-board propulsion system using storable liquid propellants is chosen in order to minimize propellant mass requirements, and the use of a parking orbit below the desired final orbit is suggested as a means to increase the flexibility of the mass launch concept. A vehicle design using composite materials is proposed that will best meet the structural requirements, and a preliminary launch tube design is presented.

  17. Elimination of Airborne Lead Contamination from Caliber .22 Ammunition.

    DTIC Science & Technology

    1987-06-01

    R191 365 ELIMINATION OF AIRBORNE LEAD CONTAMINATION FROM CALIBER 1/1 Ri ’ 3 5 22 N INITION(U) ARMY ARMAMENT RESEARCH DE VELOPMENT AM D...E JUNE 1987 U. S. MMW ARKM SRcKH, IDVROPMEff n U COOE US" ARMY EARMLMA CLOSE COMBAT ARMAMENT CENTER - MUNITBONS Et CHEMICAL COMMANDR D RA - A9~laIENT...Command tasked the U.S. Army Armament, Research , Development and Engineering Center (ARDEC) to determine if the sources of lead contamination could be

  18. Improving power output of inertial energy harvesters by employing principal component analysis of input acceleration

    NASA Astrophysics Data System (ADS)

    Smilek, Jan; Hadas, Zdenek

    2017-02-01

    In this paper we propose the use of principal component analysis to process the measured acceleration data in order to determine the direction of acceleration with the highest variance on given frequency of interest. This method can be used for improving the power generated by inertial energy harvesters. Their power output is highly dependent on the excitation acceleration magnitude and frequency, but the axes of acceleration measurements might not always be perfectly aligned with the directions of movement, and therefore the generated power output might be severely underestimated in simulations, possibly leading to false conclusions about the feasibility of using the inertial energy harvester for the examined application.

  19. Radiation from Accelerated Particles in Shocks and Reconnections

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Zhang, B.; Niemiec, J.; Medvedev, M.; Hardee, P.; Mizuno, Y.; Nordlund, A.; Frederiksen, J. T.; Sol, H.; Pohl, M.; hide

    2011-01-01

    Plasma instabilities are responsible not only for the onset and mediation of collisionless shocks but also for the associated acceleration of particles. We have investigated particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. In the leading shock, electron density increases by a factor of about 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. These magnetic fields contribute to the electrons transverse deflection and, more generally, relativistic acceleration behind the shock. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. We are currently investigating the specific case of a jet colliding with an anti-parallel magnetized ambient medium. The properties of the radiation may be important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets in general, and supernova remnants.

  20. Design and development of data acquisition system for the Louisiana accelerated loading device : final report.

    DOT National Transportation Integrated Search

    1992-09-01

    The Louisiana Transportation Research Center has established a Pavement Research Facility (PRF). The core of the PRF is a testing machine that is capable of conducting full-scale simulated and accelerated load testing of pavement materials, construct...

  1. Timescale Correlation between Marine Atmospheric Exposure and Accelerated Corrosion Testing - Part 2

    NASA Technical Reports Server (NTRS)

    Montgomery, Eliza L.; Calle, Luz Marina; Curran, Jerome C.; Kolody, Mark R.

    2012-01-01

    Evaluation of metals to predict service life of metal-based structures in corrosive environments has long relied on atmospheric exposure test sites. Traditional accelerated corrosion testing relies on mimicking the exposure conditions, often incorporating salt spray and ultraviolet (UV) radiation, and exposing the metal to continuous or cyclic conditions similar to those of the corrosive environment. Their reliability to correlate to atmospheric exposure test results is often a concern when determining the timescale to which the accelerated tests can be related. Accelerated corrosion testing has yet to be universally accepted as a useful tool in predicting the long-term service life of a metal, despite its ability to rapidly induce corrosion. Although visual and mass loss methods of evaluating corrosion are the standard, and their use is crucial, a method that correlates timescales from accelerated testing to atmospheric exposure would be very valuable. This paper presents work that began with the characterization of the atmospheric environment at the Kennedy Space Center (KSC) Beachside Corrosion Test Site. The chemical changes that occur on low carbon steel, during atmospheric and accelerated corrosion conditions, were investigated using surface chemistry analytical methods. The corrosion rates and behaviors of panels subjected to long-term and accelerated corrosion conditions, involving neutral salt fog and alternating seawater spray, were compared to identify possible timescale correlations between accelerated and long-term corrosion performance. The results, as well as preliminary findings on the correlation investigation, are presented.

  2. Summary Report of Mission Acceleration Measurements for STS-78. Launched June 20, 1996

    NASA Technical Reports Server (NTRS)

    Hakimzadeh, Roshanak; Hrovat, Kenneth; McPherson, Kevin M.; Moskowitz, Milton E.; Rogers, Melissa J. B.

    1997-01-01

    The microgravity environment of the Space Shuttle Columbia was measured during the STS-78 mission using accelerometers from three different instruments: the Orbital Acceleration Research Experiment, the Space Acceleration Measurement System and the Microgravity Measurement Assembly. The quasi-steady environment was also calculated in near real-time during the mission by the Microgravity Analysis Workstation. The Orbital Acceleration Research Experiment provided investigators with real-time quasi-steady acceleration measurements. The Space Acceleration Measurement System recorded higher frequency data on-board for post-mission analysis. The Microgravity Measurement Assembly provided investigators with real-time quasi-steady and higher frequency acceleration measurements. The Microgravity Analysis Workstation provided calculation of the quasi-steady environment. This calculation was presented to the science teams in real-time during the mission. The microgravity environment related to several different Orbiter, crew and experiment operations is presented and interpreted in this report. A radiator deploy, the Flight Control System checkout, and a vernier reaction control system reboost demonstration had minimal effects on the acceleration environment, with excitation of frequencies in the 0.01 to 10 Hz range. Flash Evaporator System venting had no noticeable effect on the environment while supply and waste water dumps caused excursions of 2 x lO(exp -6) to 4 x 10(exp -6) g in the Y(sub b) and Z(sub b) directions. Crew sleep and ergometer exercise periods can be clearly seen in the acceleration data, as expected. Accelerations related to the two Life Science Laboratory Equipment Refrigerator/Freezers were apparent in the data as are accelerations caused by the Johnson Space Center Projects Centrifuge. As on previous microgravity missions, several signals are present in the acceleration data for which a source has not been identified. The causes of these accelerations

  3. Pyroelectric Crystal Accelerator In The Department Of Physics And Nuclear Engineering At West Point

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

    Gillich, Don; Kovanen, Andrew; Anderson, Tom

    The Nuclear Science and Engineering Research Center (NSERC), a Defense Threat Reduction Agency (DTRA) office located at the United States Military Academy (USMA), sponsors and manages cadet and faculty research in support of DTRA objectives. The NSERC has created an experimental pyroelectric crystal accelerator program to enhance undergraduate education at USMA in the Department of Physics and Nuclear Engineering. This program provides cadets with hands-on experience in designing their own experiments using an inexpensive tabletop accelerator. This device uses pyroelectric crystals to ionize and accelerate gas ions to energies of {approx}100 keV. Within the next year, cadets and faculty atmore » USMA will use this device to create neutrons through the deuterium-deuterium (D-D) fusion process, effectively creating a compact, portable neutron generator. The double crystal pyroelectric accelerator will also be used by students to investigate neutron, x-ray, and ion spectroscopy.« less

  4. The Reading Writing Center: What We Can Do

    ERIC Educational Resources Information Center

    Spillane, Lee Ann

    2006-01-01

    Writing centers offer students the means to success. The Reading Writing Center (RWC) at University High School in Orlando, Florida, serves a diverse population of more than 3,700 students. The center serves dual purposes. A classroom side operates as a demonstration space where the author, who is the center's director, leads and sometimes…

  5. First time description of early lead failure of the Linox Smart lead compared to other contemporary high-voltage leads.

    PubMed

    Weberndörfer, Vanessa; Nyffenegger, Tobias; Russi, Ian; Brinkert, Miriam; Berte, Benjamin; Toggweiler, Stefan; Kobza, Richard

    2018-05-01

    Early lead failure has recently been reported in ICD patients with Linox SD leads. We aimed to compare the long-term performance of the following lead model Linox Smart SD with other contemporary high-voltage leads. All patients receiving high-voltage leads at our center between November 2009 and May 2017 were retrospectively analyzed. Lead failure was defined as the occurrence of one or more of the following: non-physiological high-rate episodes, low- or high-voltage impedance anomalies, undersensing, or non-capture. In total, 220 patients were included (Linox Smart SD, n = 113; contemporary lead, n = 107). During a median follow-up of 3.8 years (IQR 1.6-5.9 years), a total of 16 (14 in Linox Smart SD and 2 in contemporary group) lead failures occurred, mostly due to non-physiological high-rate sensing or impedance abnormalities. Lead failure incidence rates per 100 person-years were 2.9 (95% CI 1.7-4.9) and 0.6 (95% CI 0.1-2.3) for Linox Smart SD compared to contemporary leads respectively. Kaplan Meier estimates of 5-year lead failure rates were 14.0% (95% CI 8.1-23.6%) and 1.3% (95% CI 0.2-8.9%), respectively (log-rank p = 0.028). Implantation of a Linox Smart SD lead increased the risk of lead failure with a hazard ratio (HR) of 4.53 (95% CI 1.03-19.95, p = 0.046) and 4.44 (95% CI 1.00-19.77, p = 0.05) in uni- and multivariable Cox models. The new Linox Smart SD lead model was associated with high failure rates and should be monitored closely to detect early signs of lead failure.

  6. Energy spread minimization in a cascaded laser wakefield accelerator via velocity bunching

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

    Zhang, Zhijun; Li, Wentao; Wang, Wentao

    2016-05-15

    We propose a scheme to minimize the energy spread of an electron beam (e-beam) in a cascaded laser wakefield accelerator to the one-thousandth-level by inserting a stage to compress its longitudinal spatial distribution. In this scheme, three-segment plasma stages are designed for electron injection, e-beam length compression, and e-beam acceleration, respectively. The trapped e-beam in the injection stage is transferred to the zero-phase region at the center of one wakefield period in the compression stage where the length of the e-beam can be greatly shortened owing to the velocity bunching. After being seeded into the third stage for acceleration, themore » e-beam can be accelerated to a much higher energy before its energy chirp is compensated owing to the shortened e-beam length. A one-dimensional theory and two-dimensional particle-in-cell simulations have demonstrated this scheme and an e-beam with 0.2% rms energy spread and low transverse emittance could be generated without loss of charge.« less

  7. Deaths: Leading Causes for 2014.

    PubMed

    Heron, Melonie

    2016-06-01

    Objectives-This report presents final 2014 data on the 10 leading causes of death in the United States by age, sex, race, and Hispanic origin. Leading causes of infant, neonatal, and postneonatal death are also presented. This report supplements "Deaths: Final Data for 2014," the National Center for Health Statistics' annual report of final mortality statistics. All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.

  8. Shielding analyses for repetitive high energy pulsed power accelerators

    NASA Astrophysics Data System (ADS)

    Jow, H. N.; Rao, D. V.

    Sandia National Laboratories (SNL) designs, tests and operates a variety of accelerators that generate large amounts of high energy Bremsstrahlung radiation over an extended time. Typically, groups of similar accelerators are housed in a large building that is inaccessible to the general public. To facilitate independent operation of each accelerator, test cells are constructed around each accelerator to shield it from the radiation workers occupying surrounding test cells and work-areas. These test cells, about 9 ft. high, are constructed of high density concrete block walls that provide direct radiation shielding. Above the target areas (radiation sources), lead or steel plates are used to minimize skyshine radiation. Space, accessibility and cost considerations impose certain restrictions on the design of these test cells. SNL Health Physics division is tasked to evaluate the adequacy of each test cell design and compare resultant dose rates with the design criteria stated in DOE Order 5480.11. In response, SNL Health Physics has undertaken an intensive effort to assess existing radiation shielding codes and compare their predictions against measured dose rates. This paper provides a summary of the effort and its results.

  9. Construction of Two-Axis Acceleration Sensor Using a Cross-Coupled Vibrator

    NASA Astrophysics Data System (ADS)

    Terada, Jiro; Uetsuji, Yasutomo; Sugawara, Sumio

    2012-10-01

    We describe an acceleration sensor composed of four vibration bars, with a detection mechanism in which the resonant frequencies of the four bars are brought close together. The bars are connected mechanically at the center, and a cross-shaped layout is used such that for any load direction, the sizes of the loads on the vibration bars mutually oppose each other. Using this structure, acceleration can be easily calculated by differential detection of the oscillation amplitude signals of each of the four vibration bars. The body of the sensor is made of stainless steel (SUS304). The volume of the experimental sample is about 76 ×76 ×8 mm3, and the resonance frequency and quality factor are about 1041 Hz and 87, respectively. The sensor characteristics are measured using the gravitational field, and the acceleration is changed by rotating the sensor around the axis along the length of the vibrator.

  10. Stochastic shock response spectrum decomposition method based on probabilistic definitions of temporal peak acceleration, spectral energy, and phase lag distributions of mechanical impact pyrotechnic shock test data

    NASA Astrophysics Data System (ADS)

    Hwang, James Ho-Jin; Duran, Adam

    2016-08-01

    Most of the times pyrotechnic shock design and test requirements for space systems are provided in Shock Response Spectrum (SRS) without the input time history. Since the SRS does not describe the input or the environment, a decomposition method is used to obtain the source time history. The main objective of this paper is to develop a decomposition method producing input time histories that can satisfy the SRS requirement based on the pyrotechnic shock test data measured from a mechanical impact test apparatus. At the heart of this decomposition method is the statistical representation of the pyrotechnic shock test data measured from the MIT Lincoln Laboratory (LL) designed Universal Pyrotechnic Shock Simulator (UPSS). Each pyrotechnic shock test data measured at the interface of a test unit has been analyzed to produce the temporal peak acceleration, Root Mean Square (RMS) acceleration, and the phase lag at each band center frequency. Maximum SRS of each filtered time history has been calculated to produce a relationship between the input and the response. Two new definitions are proposed as a result. The Peak Ratio (PR) is defined as the ratio between the maximum SRS and the temporal peak acceleration at each band center frequency. The ratio between the maximum SRS and the RMS acceleration is defined as the Energy Ratio (ER) at each band center frequency. Phase lag is estimated based on the time delay between the temporal peak acceleration at each band center frequency and the peak acceleration at the lowest band center frequency. This stochastic process has been applied to more than one hundred pyrotechnic shock test data to produce probabilistic definitions of the PR, ER, and the phase lag. The SRS is decomposed at each band center frequency using damped sinusoids with the PR and the decays obtained by matching the ER of the damped sinusoids to the ER of the test data. The final step in this stochastic SRS decomposition process is the Monte Carlo (MC

  11. Compact Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2004-01-01

    A plasma accelerator has been conceived for both material-processing and spacecraft-propulsion applications. This accelerator generates and accelerates ions within a very small volume. Because of its compactness, this accelerator could be nearly ideal for primary or station-keeping propulsion for spacecraft having masses between 1 and 20 kg. Because this accelerator is designed to generate beams of ions having energies between 50 and 200 eV, it could also be used for surface modification or activation of thin films.

  12. Microelectromechanical acceleration-sensing apparatus

    DOEpatents

    Lee, Robb M [Albuquerque, NM; Shul, Randy J [Albuquerque, NM; Polosky, Marc A [Albuquerque, NM; Hoke, Darren A [Albuquerque, NM; Vernon, George E [Rio Rancho, NM

    2006-12-12

    An acceleration-sensing apparatus is disclosed which includes a moveable shuttle (i.e. a suspended mass) and a latch for capturing and holding the shuttle when an acceleration event is sensed above a predetermined threshold level. The acceleration-sensing apparatus provides a switch closure upon sensing the acceleration event and remains latched in place thereafter. Examples of the acceleration-sensing apparatus are provided which are responsive to an acceleration component in a single direction (i.e. a single-sided device) or to two oppositely-directed acceleration components (i.e. a dual-sided device). A two-stage acceleration-sensing apparatus is also disclosed which can sense two acceleration events separated in time. The acceleration-sensing apparatus of the present invention has applications, for example, in an automotive airbag deployment system.

  13. Heating and acceleration of escaping planetary ions

    NASA Astrophysics Data System (ADS)

    Nilsson, Hans

    2010-05-01

    The magnetic field of the Earth acts like a shield against the solar wind, leading to a magnetopause position many planetary radii away from the planet, in contrast to the situation at non- or weakly magnetized planets such as Mars and Venus. Despite this there is significant ion outflow due to solar wind interaction from the cusp and polar cap regions of the Earth's ionosphere. Effective interaction regions form, in particular in the ionospheric projection of the cusp, where ionospheric plasma flows up along the field-lines in response to magnetospheric energy input. Strong wave-particle interaction at altitudes above the ionosphere further accelerates the particles so that gravity is overcome. For the particles to enter a direct escape path they must be accelerated along open magnetic field lines so that they cross the magnetopause or reach a distance beyond the region of return flow in the tail. This return flow may also be either lost to space or returned to the atmosphere. Throughout this transport chain the heating and acceleration experienced by the particles will have an influence on the final fate of the particles. We will present quantitative estimates of centrifugal acceleration and perpendicular heating along the escape path from the cusp, through the high altitude polar cap/mantle, based on Cluster spacecraft data. We will open up for a discussion on the benefits of a ponderomotive force description of the acceleration affecting the ion circulation and escape. Finally we will compare with the situation at the unmagnetized planets Mars and Venus and discuss to what extent a magnetic field protects an atmosphere from loss through solar wind interaction.

  14. Extracting Time-Accurate Acceleration Vectors From Nontrivial Accelerometer Arrangements.

    PubMed

    Franck, Jennifer A; Blume, Janet; Crisco, Joseph J; Franck, Christian

    2015-09-01

    Sports-related concussions are of significant concern in many impact sports, and their detection relies on accurate measurements of the head kinematics during impact. Among the most prevalent recording technologies are videography, and more recently, the use of single-axis accelerometers mounted in a helmet, such as the HIT system. Successful extraction of the linear and angular impact accelerations depends on an accurate analysis methodology governed by the equations of motion. Current algorithms are able to estimate the magnitude of acceleration and hit location, but make assumptions about the hit orientation and are often limited in the position and/or orientation of the accelerometers. The newly formulated algorithm presented in this manuscript accurately extracts the full linear and rotational acceleration vectors from a broad arrangement of six single-axis accelerometers directly from the governing set of kinematic equations. The new formulation linearizes the nonlinear centripetal acceleration term with a finite-difference approximation and provides a fast and accurate solution for all six components of acceleration over long time periods (>250 ms). The approximation of the nonlinear centripetal acceleration term provides an accurate computation of the rotational velocity as a function of time and allows for reconstruction of a multiple-impact signal. Furthermore, the algorithm determines the impact location and orientation and can distinguish between glancing, high rotational velocity impacts, or direct impacts through the center of mass. Results are shown for ten simulated impact locations on a headform geometry computed with three different accelerometer configurations in varying degrees of signal noise. Since the algorithm does not require simplifications of the actual impacted geometry, the impact vector, or a specific arrangement of accelerometer orientations, it can be easily applied to many impact investigations in which accurate kinematics need

  15. SHORT ACCELERATION TIMES FROM SUPERDIFFUSIVE SHOCK ACCELERATION IN THE HELIOSPHERE

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

    Perri, S.; Zimbardo, G., E-mail: silvia.perri@fis.unical.it

    2015-12-10

    The analysis of time profiles of particles accelerated at interplanetary shocks allows particle transport properties to be inferred. The frequently observed power-law decay upstream, indeed, implies a superdiffusive particle transport when the level of magnetic field variance does not change as the time interval from the shock front increases. In this context, a superdiffusive shock acceleration (SSA) theory has been developed, allowing us to make predictions of the acceleration times. In this work we estimate for a number of interplanetary shocks, including the solar wind termination shock, the acceleration times for energetic protons in the framework of SSA and wemore » compare the results with the acceleration times predicted by standard diffusive shock acceleration. The acceleration times due to SSA are found to be much shorter than in the classical model, and also shorter than the interplanetary shock lifetimes. This decrease of the acceleration times is due to the scale-free nature of the particle displacements in the framework of superdiffusion. Indeed, very long displacements are possible, increasing the probability for particles far from the front of the shock to return, and short displacements have a high probability of occurrence, increasing the chances for particles close to the front to cross the shock many times.« less

  16. Development Biology Worksheet Oriented Accelerated Learning on Plantae and Ecosystems for 10th-Grade Senior High School Students

    NASA Astrophysics Data System (ADS)

    Dipuja, D. A.; Lufri, L.; Ahda, Y.

    2018-04-01

    The problem that found are learning outcomes student is low on the plantae and ecosystems. Students less motivated and passive learning because learning is teacher center and teaching materials not facilitate student. Therefore, it is necessary to design a worksheet oriented accelerated learning. Accelerated learning approach that can improve motivation and learning activities. The purpose of the research was to produce worksheet oriented accelerated learning on plantae and ecosystems. This research is designed as a research and development by using Plomp model, consists of the preliminary, prototyping, and assessment phase. Data was collected through questionnaires, observation sheet, test, and documentation. The results of the research was worksheet oriented accelerated learning on plantae and ecosystems is very valid.

  17. Design of the Next Generation Target at the Lujan Neutron Scattering Center, LANSCE

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

    Ferres, Laurent

    Los Alamos National Laboratory (LANL) supports scientific research in many diverse fields such as biology, chemistry, and nuclear science. The Laboratory was established in 1943 during the Second World War to develop nuclear weapons. Today, LANL is one of the largest laboratories dedicated to nuclear defense and operates an 800 MeV proton linear accelerator for basic and applied research including: production of high- and low-energy neutrons beams, isotope production for medical applications and proton radiography. This accelerator is located at the Los Alamos Neutron Science Center (LANSCE). The work performed involved the redesign of the target for the low-energy neutronmore » source at the Lujan Neutron Scattering Center, which is one of the facilities built around the accelerator. The redesign of the target involves modeling various arrangements of the moderator-reflector-shield for the next generation neutron production target. This is done using Monte Carlo N-Particle eXtended (MCNPX), and ROOT analysis framework, a C++ based-software, to analyze the results.« less

  18. Accelerated life assessment of coating on the radar structure components in coastal environment.

    PubMed

    Liu, Zhe; Ming, ZhiMao

    2016-07-04

    This paper aimed to build an accelerated life test scheme and carry out quantitative analysis between accelerated life test in the laboratory and actual service for the coating composed of epoxy primer and polyurethane paint on structure components of some kind of radar served in the coastal environment of South China Sea. The accelerated life test scheme was built based on the service environment and failure analysis of the coating. The quantitative analysis between accelerated life test and actual service was conducted by comparing the gloss loss, discoloration, chalking, blistering, cracking and electrochemical impedance spectroscopy of the coating. The main factors leading to the coating failure were ultraviolet radiation, temperature, moisture, salt fog and loads, the accelerated life test included ultraviolet radiation, damp heat, thermal shock, fatigue and salt spray. The quantitative relationship was that one cycle of the accelerated life test was equal to actual service for one year. It was established that one cycle of the accelerated life test was equal to actual service for one year. It provided a precise way to predict actual service life of newly developed coatings for the manufacturer.

  19. Electron and Ion Acceleration Associated with Magnetotail Reconnection

    NASA Astrophysics Data System (ADS)

    Liang, Haoming

    proton acceleration associated with reconnection mainly occurs in the exhaust and is consistent with Cluster observations. Oxygen ions and protons in the pre-existing current sheet are reflected by the DFs. The reflected oxygen beam forms a hook-shaped signature in phase space. In principle, this signature can be applied to deduce the DF speed history, and thus lead to remote-sensing of the reconnection dynamics.

  20. Human-Centered Design Capability

    NASA Technical Reports Server (NTRS)

    Fitts, David J.; Howard, Robert

    2009-01-01

    For NASA, human-centered design (HCD) seeks opportunities to mitigate the challenges of living and working in space in order to enhance human productivity and well-being. Direct design participation during the development stage is difficult, however, during project formulation, a HCD approach can lead to better more cost-effective products. HCD can also help a program enter the development stage with a clear vision for product acquisition. HCD tools for clarifying design intent are listed. To infuse HCD into the spaceflight lifecycle the Space and Life Sciences Directorate developed the Habitability Design Center. The Center has collaborated successfully with program and project design teams and with JSC's Engineering Directorate. This presentation discusses HCD capabilities and depicts the Center's design examples and capabilities.

  1. A New Concept of Controller for Accelerators' Magnet Power Supplies

    NASA Astrophysics Data System (ADS)

    Visintini, Roberto; Cleva, Stefano; Cautero, Marco; Ciesla, Tomasz

    2016-04-01

    The complexity of a particle accelerator implies the remote control of very large numbers of devices, with many different typologies, either distributed along the accelerator or concentrated in locations, often far away from each other. Local and global control systems handle the devices through dedicated communication channels and interfaces. Each controlled device is practically a “smart node” performing a specific task. In addition, very often, those tasks are managed in real-time mode. The performances required to the control interface has an influence on the cost of the distributed nodes as well as on their hardware and software implementation. In large facilities (e.g. CERN) the “smart nodes” derive from specific in-house developments. Alternatively, it is possible to find on the market commercial devices, whose performances (and prices) are spread over a broad range, and spanning from proprietary design (customizable to the user's needs) to open source/design. In this paper, we will describe some applications of smart nodes in the particle accelerators field, with special focus on the power supplies for magnets. In modern accelerators, in fact, magnets and their associated power supplies constitute systems distributed along the accelerator itself, and strongly interfaced with the remote control system as well as with more specific (and often more demanding) orbit/trajectory feedback systems. We will give examples of actual systems, installed and operational on two light sources, Elettra and FERMI, located in the Elettra Research Center in Trieste, Italy.

  2. A Least-Squares Commutator in the Iterative Subspace Method for Accelerating Self-Consistent Field Convergence.

    PubMed

    Li, Haichen; Yaron, David J

    2016-11-08

    A least-squares commutator in the iterative subspace (LCIIS) approach is explored for accelerating self-consistent field (SCF) calculations. LCIIS is similar to direct inversion of the iterative subspace (DIIS) methods in that the next iterate of the density matrix is obtained as a linear combination of past iterates. However, whereas DIIS methods find the linear combination by minimizing a sum of error vectors, LCIIS minimizes the Frobenius norm of the commutator between the density matrix and the Fock matrix. This minimization leads to a quartic problem that can be solved iteratively through a constrained Newton's method. The relationship between LCIIS and DIIS is discussed. Numerical experiments suggest that LCIIS leads to faster convergence than other SCF convergence accelerating methods in a statistically significant sense, and in a number of cases LCIIS leads to stable SCF solutions that are not found by other methods. The computational cost involved in solving the quartic minimization problem is small compared to the typical cost of SCF iterations and the approach is easily integrated into existing codes. LCIIS can therefore serve as a powerful addition to SCF convergence accelerating methods in computational quantum chemistry packages.

  3. Development of a patient positioning error compensation tool for Korea Heavy-Ion Medical Accelerator Treatment Center

    NASA Astrophysics Data System (ADS)

    Kim, Min-Joo; Suh, Tae-Suk; Cho, Woong; Jung, Won-Gyun

    2015-07-01

    In this study, a potential validation tool for compensating for the patient positioning error was developed by using 2D/3D and 3D/3D image registration. For 2D/3D registration, digitallyreconstructed radiography (DRR) and three-dimensional computed tomography (3D-CT) images were applied. The ray-casting algorithm is the most straightforward method for generating DRR, so we adopted the traditional ray-casting method, which finds the intersections of a ray with all objects, voxels of the 3D-CT volume in the scene. The similarity between the extracted DRR and the orthogonal image was measured by using a normalized mutual information method. Two orthogonal images were acquired from a Cyber-knife system from the anterior-posterior (AP) and right lateral (RL) views. The 3D-CT and the two orthogonal images of an anthropomorphic phantom and of the head and neck of a cancer patient were used in this study. For 3D/3D registration, planning CT and in-room CT images were applied. After registration, the translation and the rotation factors were calculated to position a couch to be movable in six dimensions. Registration accuracies and average errors of 2.12 mm ± 0.50 mm for transformations and 1.23 ° ± 0.40 ° for rotations were acquired by using 2D/3D registration with the anthropomorphic Alderson-Rando phantom. In addition, registration accuracies and average errors of 0.90 mm ± 0.30 mm for transformations and 1.00 ° ± 0.2 ° for rotations were acquired by using CT image sets. We demonstrated that this validation tool could compensate for patient positioning errors. In addition, this research could be a fundamental step in compensating for patient positioning errors at the Korea Heavy-ion Medical Accelerator Treatment Center.

  4. MABE multibeam accelerator

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

    Hasti, D.E.; Ramirez, J.J.; Coleman, P.D.

    1985-01-01

    The Megamp Accelerator and Beam Experiment (MABE) was the technology development testbed for the multiple beam, linear induction accelerator approach for Hermes III, a new 20 MeV, 0.8 MA, 40 ns accelerator being developed at Sandia for gamma-ray simulation. Experimental studies of a high-current, single-beam accelerator (8 MeV, 80 kA), and a nine-beam injector (1.4 MeV, 25 kA/beam) have been completed, and experiments on a nine-beam linear induction accelerator are in progress. A two-beam linear induction accelerator is designed and will be built as a gamma-ray simulator to be used in parallel with Hermes III. The MABE pulsed power systemmore » and accelerator for the multiple beam experiments is described. Results from these experiments and the two-beam design are discussed. 11 refs., 6 figs.« less

  5. Stable quasi-monoenergetic ion acceleration from the laser-driven shocks in a collisional plasma

    NASA Astrophysics Data System (ADS)

    Bhadoria, Shikha; Kumar, Naveen; Keitel, Christoph H.

    2017-10-01

    Effect of collisions on the shock formation and subsequent ion acceleration from the laser-plasma interaction is explored by the means of particle-in-cell simulations. In this setup, the incident laser pushes the laser-plasma interface inside the plasma target through the hole-boring effect and generates hot electrons. The propagation of these hot electrons inside the target excites a return plasma current, leading to filamentary structures caused by the Weibel/filamentation instability. Weakening of the space-charge effects due to collisions results in the shock formation with a higher density jump than in a collisionless plasma. This results in the formation of a stronger shock leading to a stable quasi-monoenergetic acceleration of ions.

  6. Preliminary Results from Pyroelectric Crystal Accelerator

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

    Anderson, Tom; Edwards, Ronald; Bright, Kevin

    The Nuclear Science and Engineering Research Center (NSERC), a Defense Threat Reduction Agency (DTRA) office located at the United States Military Academy (USMA), sponsors and manages cadet and faculty research in support of DTRA objectives. Cadets in the Department of Physics and Nuclear Engineering at USMA are using pyroelectric crystals to ionize and accelerate residual gas trapped inside a vacuum system. A system using two lithium tantalate crystals with associated diagnostics was designed and is now operational. X-ray energies of approximately 150 keV have been achieved. Future work will focus on developing a portable neutron generator using the D-D nuclearmore » fusion process.« less

  7. Probing electron acceleration and x-ray emission in laser-plasma accelerators

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

    Thaury, C.; Ta Phuoc, K.; Corde, S.

    2013-06-15

    While laser-plasma accelerators have demonstrated a strong potential in the acceleration of electrons up to giga-electronvolt energies, few experimental tools for studying the acceleration physics have been developed. In this paper, we demonstrate a method for probing the acceleration process. A second laser beam, propagating perpendicular to the main beam, is focused on the gas jet few nanosecond before the main beam creates the accelerating plasma wave. This second beam is intense enough to ionize the gas and form a density depletion, which will locally inhibit the acceleration. The position of the density depletion is scanned along the interaction lengthmore » to probe the electron injection and acceleration, and the betatron X-ray emission. To illustrate the potential of the method, the variation of the injection position with the plasma density is studied.« less

  8. Ring-like spatial distribution of laser accelerated protons in the ultra-high-contrast TNSA-regime

    NASA Astrophysics Data System (ADS)

    Becker, G. A.; Tietze, S.; Keppler, S.; Reislöhner, J.; Bin, J. H.; Bock, L.; Brack, F.-E.; Hein, J.; Hellwing, M.; Hilz, P.; Hornung, M.; Kessler, A.; Kraft, S. D.; Kuschel, S.; Liebetrau, H.; Ma, W.; Polz, J.; Schlenvoigt, H.-P.; Schorcht, F.; Schwab, M. B.; Seidel, A.; Zeil, K.; Schramm, U.; Zepf, M.; Schreiber, J.; Rykovanov, S.; Kaluza, M. C.

    2018-05-01

    The spatial distribution of protons accelerated from submicron-thick plastic foil targets using multi-terawatt, frequency-doubled laser pulses with ultra-high temporal contrast has been investigated experimentally. A very stable, ring-like beam profile of the accelerated protons, oriented around the target’s normal direction has been observed. The ring’s opening angle has been found to decrease with increasing foil thicknesses. Two-dimensional particle-in-cell simulations reproduce our results indicating that the ring is formed during the expansion of the proton density distribution into the vacuum as described by the mechanism of target-normal sheath acceleration. Here—in addition to the longitudinal electric fields responsible for the forward acceleration of the protons—a lateral charge separation leads to transverse field components accelerating the protons in the lateral direction.

  9. FAST/Polar Conjunction Study of Field-Aligned Auroral Acceleration and Corresponding Magnetotail Drivers

    NASA Technical Reports Server (NTRS)

    Schriver, D.; Ashour-Abdalla, M.; Strangeway, R. J.; Richard, R. L.; Klezting, C.; Dotan, Y.; Wygant, J.

    2003-01-01

    The discrete aurora results when energized electrons bombard the Earth's atmosphere at high latitudes. This paper examines the physical processes that can cause field-aligned acceleration of plasma particles in the auroral region. A data and theoretical study has been carried out to examine the acceleration mechanisms that operate in the auroral zone and to identi@ the magnetospheric drivers of these acceleration mechanisms. The observations used in the study were collected by the Fast Auroral Snapshot (FAST) and Polar satellites when the two satellites were in approximate magnetic conjunction in the auroral region. During these events FAST was in the middle of the auroral zone and Polar was above the auroral zone in the near-Earth plasma sheet. Polar data were used to determine the conditions in the magnetotail at the time field-aligned acceleration was measured by FAST in the auroral zone. For each of the magnetotail drivers identified in the data study, the physics of field-aligned acceleration in the auroral region was examined using existing theoretical efforts and/or a long-system particle in cell simulation to model the magnetically connected region between the two satellites. Results from the study indicate that there are three main drivers of auroral acceleration: (1) field-aligned currents that lead to quasistatic parallel potential drops (parallel electric fields), (2) earthward flow of high-energy plasma beams from the magnetotail into the auroral zone that lead to quasistatic parallel potential drops, and (3) large-amplitude Alfven waves that propagate into the auroral region from the magnetotail. The events examined thus far confm the previously established invariant latitudinal dependence of the drivers and show a strong dependence on magnetic activity. Alfven waves tend to occur primarily at the poleward edge of the auroral region during more magnetically active times and are correlated with intense electron precipitation. At lower latitudes away

  10. Alternative Fuels Data Center: Alabama City Leads With Biodiesel and

    Science.gov Websites

    EthanolA> Alabama City Leads With Biodiesel and Ethanol to someone by E-mail Share Alternative fleets. For information about this project, contact Alabama Clean Fuels Coalition. Download QuickTime Automotive Magazine Provided by Maryland Public Television Related Videos Photo of a car Electric Vehicles

  11. Vitamin C modulates lead excretion in rats.

    PubMed

    Lihm, Hoseob; Kim, Hyun; Chang, Heekyung; Yoon, Myunghee; Lee, Kayoung; Choi, Jongsoon

    2013-12-01

    Lead, one of the most toxic heavy metals, takes longer time to be excreted from the body than other heavy metals. The purpose of this study is, by measuring lead excretion via urine and feces, to find out the effect of vitamin C in lead chelation. Thirty-six rats were randomly assorted into four groups. All 33 rats except for the control group were administered with lead, before orally administered with different doses of vitamin C per kilogram of body weight. The lead excretion levels in urine and feces as well as the survival rate were then measured for each group. The rats with lead administrations (10/13, 76.9%) with lead administrations only, 10/11 rats (90.9%) with lead administrations and low dose of vitamin C, 9/9 rats (100%) with lead administrations and high dose of vitamin C survived. Among the 29 surviving rats, low vitamin C intake group exhibited higher urinary excretion than the lead only group. The urinary excretion level in high dose vitamin C intakegroup was significantly higher than the lead only group. In addition, fecal lead excretion seemed to be increased in the high dose vitamin C intake group, compared to the group with lead administrations only with statistical significance. Through animal experiment, it was found out that administrating high dose of vitamin C accelerated the excretion of lead in body compared to low dose of vitamin C.

  12. LIGHT - from laser ion acceleration to future applications

    NASA Astrophysics Data System (ADS)

    Roth, Markus; Light Collaboration

    2013-10-01

    Creation of high intensity multi-MeV ion bunches by high power lasers became a reliable tool during the last 15 years. The laser plasma source provides for TV/m accelerating field gradients and initially sub-ps bunch lengths. However, the large envelope divergence and the continuous exponential energy spectrum are substential drawbacks for many possible applications. To face this problem, the LIGHT collaboration was founded (Laser Ion Generation, Handling and Transport). The collaboration consists of several university groups and research centers, namely TU Darmstadt, JWGU Frankfurt, HI Jena, HZDR Dresden and GSI Darmstadt. The central goal is building a test beamline for merging laser ion acceleration with conventional accelerator infrastructure at the GSI facility. In the latest experiments, low divergent proton bunches with a central energy of up to 10 MeV and containing >109 particles could be provided at up to 2.2 m behind the plasma source, using a pulsed solenoid. In a next step, a radiofrequency cavity will be added to the beamline for phase rotation of these bunches, giving access to sub-ns bunch lengths and reaching highest intensities. An overview of the LIGHT objectives and the recent experimental results will be given. This work was supported by HIC4FAIR.

  13. Effects of byproducts amended lead contaminated urban soils on collard yield

    USDA-ARS?s Scientific Manuscript database

    Lead (Pb) has been used to produce materials and manufactured products for many years. In urban areas and industrial centers atmospheric lead deposition could be very high. Urban environments in general received high deposition of lead due to leaded gasoline use, industrial activity and abandoned ...

  14. Social-emotional characteristics of gifted accelerated and non-accelerated students in the Netherlands.

    PubMed

    Hoogeveen, Lianne; van Hell, Janet G; Verhoeven, Ludo

    2012-12-01

    In the studies of acceleration conducted so far a multidimensional perspective has largely been neglected. No attempt has been made to relate social-emotional characteristics of accelerated versus non-accelerated students in perspective of environmental factors. In this study, social-emotional characteristics of accelerated gifted students in the Netherlands were examined in relation to personal and environmental factors. Self-concept and social contacts of accelerated (n = 148) and non-accelerated (n = 55) gifted students, aged 4 to 27 (M = 11.22, SD = 4.27) were measured. Self-concept and social contacts of accelerated and non-accelerated gifted students were measured using a questionnaire and a diary, and parents of these students evaluated their behavioural characteristics. Gender and birth order were studied as personal factors and grade, classroom, teachers' gender, teaching experience, and the quality of parent-school contact as environmental factors. The results showed minimal differences in the social-emotional characteristics of accelerated and non-accelerated gifted students. The few differences we found favoured the accelerated students. We also found that multiple grade skipping does not have negative effects on social-emotional characteristics, and that long-term effects of acceleration tend to be positive. As regards the possible modulation of personal and environmental factors, we merely found an impact of such factors in the non-accelerated group. The results of this study strongly suggest that social-emotional characteristics of accelerated gifted students and non-accelerated gifted students are largely similar. These results thus do not support worries expressed by teachers about the acceleration of gifted students. Our findings parallel the outcomes of earlier studies in the United States and Germany in that we observed that acceleration does not harm gifted students, not even in the case of multiple grade skipping. On the contrary, there is a

  15. Projectile Combustion Effects on Ram Accelerator Performance

    NASA Astrophysics Data System (ADS)

    Chitale, Saarth Anjali

    University of Washington Abstract Projectile Combustion Effects on Ram Accelerator Performance Saarth Anjali Chitale Chair of the Supervisory Committee: Prof. Carl Knowlen William E. Boeing Department of Aeronautics and Astronautics The ram accelerator facility at the University of Washington is used to propel projectiles at supersonic velocities. This concept is similar to an air-breathing ramjet engine in that sub-caliber projectiles, shaped like the ramjet engine center-body, are shot through smooth-bore steel-walled tubes having an internal diameter of 38 mm. The ram accelerator propulsive cycles operate between Mach 2 to 10 and have the potential to accelerate projectile to velocities greater than 8 km/s. The theoretical thrust versus Mach number characteristics can be obtained using knowledge of gas dynamics and thermodynamics that goes into the design of the ram accelerator. The corresponding velocity versus distance profiles obtained from the test runs at the University of Washington, however, are often not consistent with the theoretical predictions after the projectiles reach in-tube Mach numbers greater than 4. The experimental velocities are typically greater than the expected theoretical predictions; which has led to the proposition that the combustion process may be moving up onto the projectile. An alternative explanation for higher than predicted thrust, which is explored here, is that the performance differences can be attributed to the ablation of the projectile body which results in molten metal being added to the flow of the gaseous combustible mixture around the projectile. This molten metal is assumed to mix uniformly and react with the gaseous propellant; thereby enhancing the propellant energy release and altering the predicted thrust-Mach characteristics. This theory predicts at what Mach number the projectile will first experience enhanced thrust and the corresponding velocity-distance profile. Preliminary results are in good agreement

  16. Cost of a recall of a single-center experience managing the Riata defibrillator lead.

    PubMed

    Hussain, Sarah; Moorman, Liza; Moorman, J Randall; DiMarco, John P; Malhotra, Rohit; Darby, Andrew; Bilchick, Kenneth; Mangrum, J Michael; Ferguson, John D; Mason, Pamela K

    2015-01-15

    Riata and Riata ST defibrillator leads (St. Jude Medical, Sylmar, California) were recalled in 2011 due to increased risk of insulation failure leading to externalized cables. Fluoroscopic screening can identify insulation failure, although the relation between mechanical failure and electrical failure is unclear. At the time of the recall, the University of Virginia developed a screening program, including fluoroscopic evaluation, education sessions, device interrogation, and remote monitoring for patients with this defibrillator lead. The aim of this study was to review the outcomes of the screening program, including costs, which were absorbed by our institution. Costs were calculated using Medicare reimbursement estimates. Forty-eight patients participated in the screening program. At initial screening, 31% were found to have evidence of insulation failure but electrical function was normal in all leads. The cost of this program was $35,358.72. The cost per diagnosis of mechanical lead failure was $2,357.25. During 2 years of follow-up, 1 patient experienced Riata lead electrical failure without fluoroscopic evidence of insulation failure. Patients were more likely to have a lead revision if there was evidence of insulation failure. Lead revisions occurred at the time of generator change in 88% of patients with insulation failure but in only 14% of patients with a fluoroscopically normal lead (p = 0.04). The cost of recall-related defibrillator lead revisions was $81,704.55. In conclusion, our Riata screening program added expense without clear benefit to patients. In fact, patients may have been put at more risk by undergoing defibrillator lead revisions based solely on the results of the fluoroscopic screening. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Declining blood lead levels and cognitive changes in moderately lead-poisoned children.

    PubMed

    Ruff, H A; Bijur, P E; Markowitz, M; Ma, Y C; Rosen, J F

    1993-04-07

    To determine whether chelation therapy or biochemical changes during a lead-lowering intervention was associated with changes in cognitive functioning of moderately lead-poisoned children. It was hypothesized that cognitive performance would improve as blood lead level declined over time. Short-term intervention study with measures obtained before and after intervention. Hospital specialty clinic and university research center. A total of 154 previously untreated children referred to clinic with blood lead levels between 1.21 and 2.66 mumol/L (25 and 55 micrograms/dL) at time of enrollment. Ages ranged from 13 to 87 months. Enrolled children were treated with edetate calcium disodium (EDTA) if eligible and/or with orally administered iron supplement if iron deficient. For all children, housing inspections and abatement procedures were performed as necessary. Score on Bayley Mental Development Scale or Stanford-Binet Intelligence Scale (4th edition). There was no effect of edetate calcium disodium treatment per se. In the short term (7 weeks), changes in blood lead levels were not related to changes in cognitive scores. In the long term (6 months), however, changes in performance were significantly related to changes in blood lead level, even after controlling for confounding variables. The standardized score increased 1 point for every decrease of 0.14 mumol/L (3 micrograms/dL) in blood lead level. The results suggest an association between decreases in blood lead level and cognitive improvements in moderately lead-poisoned children.

  18. Ligand-accelerated enantioselective methylene C(sp3)-H bond activation.

    PubMed

    Chen, Gang; Gong, Wei; Zhuang, Zhe; Andrä, Michal S; Chen, Yan-Qiao; Hong, Xin; Yang, Yun-Fang; Liu, Tao; Houk, K N; Yu, Jin-Quan

    2016-09-02

    Effective differentiation of prochiral carbon-hydrogen (C-H) bonds on a single methylene carbon via asymmetric metal insertion remains a challenge. Here, we report the discovery of chiral acetyl-protected aminoethyl quinoline ligands that enable asymmetric palladium insertion into prochiral C-H bonds on a single methylene carbon center. We apply these palladium complexes to catalytic enantioselective functionalization of β-methylene C-H bonds in aliphatic amides. Using bidentate ligands to accelerate C-H activation of otherwise unreactive monodentate substrates is crucial for outcompeting the background reaction driven by substrate-directed cyclopalladation, thereby avoiding erosion of enantioselectivity. The potential of ligand acceleration in C-H activation is also demonstrated by enantioselective β-C-H arylation of simple carboxylic acids without installing directing groups. Copyright © 2016, American Association for the Advancement of Science.

  19. An innovative approach to accelerated baccalaureate education.

    PubMed

    Walker, Charles; Tilley, Donna Scott; Lockwood, Suzanne; Walker, Mary Beth

    2008-01-01

    This article highlights novelties and innovations that were successfully incorporated in the development and ongoing refinement of an accelerated nursing program for second-degree students. Using a reflective practice framework, program coordinators deliberately crafted incoming classes through constrained optimization, modified the clinical rotation model, reduced waste through efficient use of faculty and other resources, integrated clinical course work to promote contextual learning, introduced four semester themes to mitigate an obsession with content among faculty and students, and employed student-centered pedagogies that valued the depth and breadth of students' prior experiences. Program outcomes are also discussed.

  20. Barriers and facilitators to senior centers participating in translational research.

    PubMed

    Felix, Holly C; Adams, Becky; Cornell, Carol E; Fausett, Jennifer K; Krukowski, Rebecca A; Love, ShaRhonda J; Prewitt, T Elaine; West, Delia Smith

    2014-01-01

    Senior centers are ideal locations to deliver evidence-based health promotion programs to the rapidly growing population of older Americans to help them remain healthy and independent in the community. However, little reported research is conducted in partnership with senior centers; thus, not much is known about barriers and facilitators for senior centers serving as research sites. To fill this gap and potentially accelerate research within senior centers to enhance translation of evidence-based interventions into practice, the present study examined barriers and facilitators of senior centers invited to participate in a cluster-randomized controlled trial. Primary barriers to participation related to staffing and perceived inability to recruit older adult participants meeting research criteria. The primary facilitator was a desire to offer programs that were of interest and beneficial to seniors. Senior centers are interested in participating in research that provides benefit to older adults but may need assistance from researchers to overcome participation barriers. © The Author(s) 2012.

  1. Ambulatory surgery centers--current business and legal issues.

    PubMed

    Becker, S; Biala, M

    2000-01-01

    This article explores a handful of critical trends that have broad implications for ambulatory surgery centers and health care entities as a whole. As of the year 2000, the health care delivery system is experiencing broad changes and reconstruction in a variety of manners. One of the largest changes revolves around the accelerating movement of patient care from inpatient models to outpatient models, and the commensurate investment and development in outpatient systems and outpatient bricks and mortar. This metamorphosis is particularly evident as it relates to freestanding ambulatory surgery centers. This change in health care delivery will prove to have severe economic impacts on many of the nation's hospital systems.

  2. Embedded ice with lead

    NASA Image and Video Library

    2017-12-08

    Iceberg embedded in sea ice with a lead on one side. This opening was likely caused by winds blowing against the side of the iceberg. Credit: NASA / George Hale NASA's Operation IceBridge is an airborne science mission to study Earth's polar ice. For more information about IceBridge, visit: www.nasa.gov/icebridge NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  3. Trends in Arctic Sea Ice Leads Detection

    NASA Astrophysics Data System (ADS)

    Ackerman, S. A.; Hoffman, J.; Liu, Y.; Key, J. R.

    2016-12-01

    Sea ice leads (fractures) play a critical role in the exchange of mass and energy between the ocean and atmosphere in the polar regions, particularly in the Arctic. Leads result in warming water and accelerated melting because leads absorb more solar energy than the surrounding ice. In the autumn, winter, and spring leads impact the local atmospheric structure and cloud properties because of the large flux of heat and moisture into the atmosphere. Given the rapid thinning and loss of Arctic sea ice over the last few decades, changes in the distribution of leads can be expected in response. Leads are largely wind driven, so their distributions will also be affected by the changes in atmospheric circulation that have occurred. From a climate perspective, identifying trends in lead characteristics (width, orientation, and spatial distribution) will advance our understanding of both thermodynamic and mechanical processes. This study presents the spatial and temporal distributions of Arctic sea ice leads since 2002 using a new method to detect and characterize sea ice leads with optical (visible, infrared) satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS). Using reflective and emissive channels, ice concentration is derived in cloud-free regions and used to create a mask of potential leads. An algorithm then uses a combination of image processing techniques to identify and characterizes leads. The results show interannual variability of leads positioning as well as parameters such as area, length, orientation and width.

  4. Trunk Acceleration for Neuroprosthetic Control of Standing – a Pilot Study

    PubMed Central

    Audu, Musa L.; Kirsch, Robert F.; Triolo, Ronald J.

    2013-01-01

    This pilot study investigated the potential of using trunk acceleration feedback control of center of pressure (COP) against postural disturbances with a standing neuroprosthesis following paralysis. Artificial neural networks (ANNs) were trained to use three-dimensional trunk acceleration as input to predict changes in COP for able-bodied subjects undergoing perturbations during bipedal stance. Correlation coefficients between ANN predictions and actual COP ranged from 0.67 to 0.77. An ANN trained across all subject-normalized data was used to drive feedback control of ankle muscle excitation levels for a computer model representing a standing neuroprosthesis user. Feedback control reduced average upper-body loading during perturbation onset and recovery by 42% and peak loading by 29% compared to optimal, constant excitation. PMID:21975251

  5. Lead Exposure of People with Developmental Disabilities: Success of Control Measures.

    ERIC Educational Resources Information Center

    Lohiya, Ghan Shyam; And Others

    1996-01-01

    In a developmental center for individuals with mental retardation, blood lead level was determined for individuals who were admitted or discharged over two decades. Analysis indicated a marked decline in blood lead levels, attributed to local lead abatement measures, effective pica management, and reduced environmental lead contamination.…

  6. Measurement of Impact Acceleration: Mouthpiece Accelerometer Versus Helmet Accelerometer

    PubMed Central

    Higgins, Michael; Halstead, P. David; Snyder-Mackler, Lynn; Barlow, David

    2007-01-01

    Context: Instrumented helmets have been used to estimate impact acceleration imparted to the head during helmet impacts. These instrumented helmets may not accurately measure the actual amount of acceleration experienced by the head due to factors such as helmet-to-head fit. Objective: To determine if an accelerometer attached to a mouthpiece (MP) provides a more accurate representation of headform center of gravity (HFCOG) acceleration during impact than does an accelerometer attached to a helmet fitted on the headform. Design: Single-factor research design in which the independent variable was accelerometer position (HFCOG, helmet, MP) and the dependent variables were g and Severity Index (SI). Setting: Independent impact research laboratory. Intervention(s): The helmeted headform was dropped (n = 168) using a National Operating Committee on Standards for Athletic Equipment (NOCSAE) drop system from the standard heights and impact sites according to NOCSAE test standards. Peak g and SI were measured for each accelerometer position during impact. Main Outcome Measures: Upon impact, the peak g and SI were recorded for each accelerometer location. Results: Strong relationships were noted for HFCOG and MP measures, and significant differences were seen between HFCOG and helmet g measures and HFCOG and helmet SI measures. No statistically significant differences were noted between HFCOG and MP g and SI measures. Regression analyses showed a significant relationship between HFCOG and MP measures but not between HFCOG and helmet measures. Conclusions: Upon impact, MP acceleration (g) and SI measurements were closely related to and more accurate in measuring HFCOG g and SI than helmet measurements. The MP accelerometer is a valid method for measuring head acceleration. PMID:17597937

  7. An accelerated test design for use with synchronous orbit. [on Ni-Cd cell degradation behavior

    NASA Technical Reports Server (NTRS)

    Mcdermott, P. P.; Vasanth, K. L.

    1980-01-01

    The Naval Weapons Support Center at Crane, Indiana has conducted a large scale accelerated test of 6.0 Ah Ni-Cd cells. Data from the Crane test have been used to develop an equation for the description of Ni-Cd cell behavior in geosynchronous orbit. This equation relates the anticipated time to failure for a cell in synchronous orbit to temperature and overcharge rate sustained by the cell during the light period. A test design is suggested which uses this equation for setting test parameters for future accelerated testing.

  8. Semiconductor acceleration sensor

    NASA Astrophysics Data System (ADS)

    Ueyanagi, Katsumichi; Kobayashi, Mitsuo; Goto, Tomoaki

    1996-09-01

    This paper reports a practical semiconductor acceleration sensor especially suited for automotive air bag systems. The acceleration sensor includes four beams arranged in a swastika structure. Two piezoresistors are formed on each beam. These eight piezoresistors constitute a Wheatstone bridge. The swastika structure of the sensing elements, an upper glass plate and a lower glass plate exhibit the squeeze film effect which enhances air dumping, by which the constituent silicon is prevented from breakdown. The present acceleration sensor has the following features. The acceleration force component perpendicular to the sensing direction can be cancelled. The cross-axis sensitivity is less than 3 percent. And, the erroneous offset caused by the differences between the thermal expansion coefficients of the constituent materials can be canceled. The high aspect ratio configuration realized by plasma etching facilitates reducing the dimensions and improving the sensitivity of the acceleration sensor. The present acceleration sensor is 3.9 mm by 3.9 mm in area and 1.2 mm in thickness. The present acceleration sensor can measure from -50 to +50 G with sensitivity of 0.275 mV/G and with non-linearity of less than 1 percent. The acceleration sensor withstands shock of 3000 G.

  9. EDITORIAL: Laser and Plasma Accelerators Workshop, Kardamyli, Greece, 2009 Laser and Plasma Accelerators Workshop, Kardamyli, Greece, 2009

    NASA Astrophysics Data System (ADS)

    Bingham, Bob; Muggli, Patric

    2011-01-01

    The Laser and Plasma Accelerators Workshop 2009 was part of a very successful series of international workshops which were conceived at the 1985 Laser Acceleration of Particles Workshop in Malibu, California. Since its inception, the workshop has been held in Asia and in Europe (Kardamyli, Kyoto, Presqu'ile de Giens, Portovenere, Taipei and the Azores). The purpose of the workshops is to bring together the most recent results in laser wakefield acceleration, plasma wakefield acceleration, laser-driven ion acceleration, and radiation generation produced by plasma-based accelerator beams. The 2009 workshop was held on 22-26 June in Kardamyli, Greece, and brought together over 80 participants. (http://cfp.ist.utl.pt/lpaw09/). The workshop involved five main themes: • Laser plasma electron acceleration (experiment/theory/simulation) • Computational methods • Plasma wakefield acceleration (experiment/theory/simulation) • Laser-driven ion acceleration • Radiation generation and application. All of these themes are covered in this special issue of Plasma Physics and Controlled Fusion. The topic and application of plasma accelerators is one of the success stories in plasma physics, with laser wakefield acceleration of mono-energetic electrons to GeV energies, of ions to hundreds of MeV, and electron-beam-driven wakefield acceleration to 85 GeV. The accelerating electric field in the wake is of the order 1 GeV cm-1, or an accelerating gradient 1000 times greater than in conventional accelerators, possibly leading to an accelerator 1000 times smaller (and much more affordable) for the same energy. At the same time, the electron beams generated by laser wakefield accelerators have very good emittance with a correspondingly good energy spread of about a few percent. They also have the unique feature in being ultra-short in the femtosecond scale. This makes them attractive for a variety of applications, ranging from material science to ultra-fast time

  10. Untangling the Effect of Head Acceleration on Brain Responses to Blast Waves

    PubMed Central

    Mao, Haojie; Unnikrishnan, Ginu; Rakesh, Vineet; Reifman, Jaques

    2015-01-01

    Multiple injury-causing mechanisms, such as wave propagation, skull flexure, cavitation, and head acceleration, have been proposed to explain blast-induced traumatic brain injury (bTBI). An accurate, quantitative description of the individual contribution of each of these mechanisms may be necessary to develop preventive strategies against bTBI. However, to date, despite numerous experimental and computational studies of bTBI, this question remains elusive. In this study, using a two-dimensional (2D) rat head model, we quantified the contribution of head acceleration to the biomechanical response of brain tissues when exposed to blast waves in a shock tube. We compared brain pressure at the coup, middle, and contre-coup regions between a 2D rat head model capable of simulating all mechanisms (i.e., the all-effects model) and an acceleration-only model. From our simulations, we determined that head acceleration contributed 36–45% of the maximum brain pressure at the coup region, had a negligible effect on the pressure at the middle region, and was responsible for the low pressure at the contre-coup region. Our findings also demonstrate that the current practice of measuring rat brain pressures close to the center of the brain would record only two-thirds of the maximum pressure observed at the coup region. Therefore, to accurately capture the effects of acceleration in experiments, we recommend placing a pressure sensor near the coup region, especially when investigating the acceleration mechanism using different experimental setups. PMID:26458125

  11. The Future of Dental Schools in Research Universities and Academic Health Centers.

    PubMed

    McCauley, Laurie K

    2017-09-01

    As a profession, dentistry is at a point of discernible challenge as well as incredible opportunity in a landscape of evolving changes to health care, higher education, and evidence-based decision making. Respecting the past yet driving forward, a well-mapped future course is critical. Orchestrating this course in a collaborative manner is essential for the visibility, well-being, and potentially the existence of the dental profession. The research performed in dental institutions needs to be contemporary, aligned with biomedical science in general, and united with other disciplines. Dentistry is at risk of attrition in the quality of its research and discovery mission if participation with bioscience colleagues in the collaborative generation of new knowledge is underoptimized. A fundamental opportunity dentistry has is to contribute via its position in academic health centers. Rigorous research as to the impact of interprofessional education and collaborative care on population health outcomes provides significant potential for the dental profession to participate and/or lead such evidence-centered efforts. It is imperative that academic dental institutions are part of interdisciplinary and transdisciplinary organizations that move health care into its new day. Strategizing diversity by bringing together people who have different ways of seeing problems to share perspectives, heuristics, interpretations, technologies, and predictive models across disciplines will lead to impactful progress. Academic dental institutions are a natural part of an emphasis on translational research and acceleration of implementing new scientific discoveries. Dentistry needs to remain an essential and integrated component of higher education in the health professions; doing so necessitates deliberate, respectful, and committed change. This article was written as part of the project "Advancing Dental Education in the 21 st Century."

  12. SuperB Progress Report for Accelerator

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

    Biagini, M.E.; Boni, R.; Boscolo, M.

    2012-02-14

    This report details the progress made in by the SuperB Project in the area of the Collider since the publication of the SuperB Conceptual Design Report in 2007 and the Proceedings of SuperB Workshop VI in Valencia in 2008. With this document we propose a new electron positron colliding beam accelerator to be built in Italy to study flavor physics in the B-meson system at an energy of 10 GeV in the center-of-mass. This facility is called a high luminosity B-factory with a project name 'SuperB'. This project builds on a long history of successful e+e- colliders built around themore » world, as illustrated in Figure 1.1. The key advances in the design of this accelerator come from recent successes at the DAFNE collider at INFN in Frascati, Italy, at PEP-II at SLAC in California, USA, and at KEKB at KEK in Tsukuba Japan, and from new concepts in beam manipulation at the interaction region (IP) called 'crab waist'. This new collider comprises of two colliding beam rings, one at 4.2 GeV and one at 6.7 GeV, a common interaction region, a new injection system at full beam energies, and one of the two beams longitudinally polarized at the IP. Most of the new accelerator techniques needed for this collider have been achieved at other recently completed accelerators including the new PETRA-3 light source at DESY in Hamburg (Germany) and the upgraded DAFNE collider at the INFN laboratory at Frascati (Italy), or during design studies of CLIC or the International Linear Collider (ILC). The project is to be designed and constructed by a worldwide collaboration of accelerator and engineering staff along with ties to industry. To save significant construction costs, many components from the PEP-II collider at SLAC will be recycled and used in this new accelerator. The interaction region will be designed in collaboration with the particle physics detector to guarantee successful mutual use. The accelerator collaboration will consist of several groups at present universities and

  13. Microbial strategy for potential lead remediation: a review study.

    PubMed

    Pan, Xiaohong; Chen, Zhi; Li, Lan; Rao, Wenhua; Xu, Zhangyan; Guan, Xiong

    2017-02-01

    The extensive exploitation and usage of lead compounds result in severe lead(II) pollution in water and soil environments, even in agricultural land, threatening the health of animals and humans via food chains. The recovery and remediation of lead(II) from water and soil environments have been intensively concerned in recent years. Compared with the traditional physic-chemistry treatment, microbial remediation strategy is a promising alternative to remediate lead(II)-contaminated environments due to its cost-effective and environmentally-friendly properties. Various microorganisms are capable of removing or immobilizing lead(II) from water and soil environments through bioaccumulation, precipitation or accelerated transformation of lead(II) into a very stable mineral, resulting in significant effects on lead(II) mobility and bioavailability. In the present review, we investigated a wide diversity of lead(II) bioremediation induced by different microbes and its multi-mechanisms. Moreover, we also discussed the progress and limitations, summarized the common rules of lead(II)-microbe interaction, and evaluated the environmental significance of microbes in lead biogeochemistry process. In addition, we further deliberated the feasibility and potential application of microbes in developing cost-effective, eco-friendly bioremediation or long-term management strategy for lead(II) contaminated repositories.

  14. Direct longitudinal laser acceleration of electrons in free space

    NASA Astrophysics Data System (ADS)

    Carbajo, Sergio; Nanni, Emilio A.; Wong, Liang Jie; Moriena, Gustavo; Keathley, Phillip D.; Laurent, Guillaume; Miller, R. J. Dwayne; Kärtner, Franz X.

    2016-02-01

    Compact laser-driven accelerators are pursued heavily worldwide because they make novel methods and tools invented at national laboratories widely accessible in science, health, security, and technology [V. Malka et al., Principles and applications of compact laser-plasma accelerators, Nat. Phys. 4, 447 (2008)]. Current leading laser-based accelerator technologies [S. P. D. Mangles et al., Monoenergetic beams of relativistic electrons from intense laser-plasma interactions, Nature (London) 431, 535 (2004); T. Toncian et al., Ultrafast laser-driven microlens to focus and energy-select mega-electron volt protons, Science 312, 410 (2006); S. Tokita et al. Single-shot ultrafast electron diffraction with a laser-accelerated sub-MeV electron pulse, Appl. Phys. Lett. 95, 111911 (2009)] rely on a medium to assist the light to particle energy transfer. The medium imposes material limitations or may introduce inhomogeneous fields [J. R. Dwyer et al., Femtosecond electron diffraction: "Making the molecular movie,", Phil. Trans. R. Soc. A 364, 741 (2006)]. The advent of few cycle ultraintense radially polarized lasers [S. Carbajo et al., Efficient generation of ultraintense few-cycle radially polarized laser pulses, Opt. Lett. 39, 2487 (2014)] has ushered in a novel accelerator concept [L. J. Wong and F. X. Kärtner, Direct acceleration of an electron in infinite vacuum by a pulsed radially polarized laser beam, Opt. Express 18, 25035 (2010); F. Pierre-Louis et al. Direct-field electron acceleration with ultrafast radially polarized laser beams: Scaling laws and optimization, J. Phys. B 43, 025401 (2010); Y. I. Salamin, Electron acceleration from rest in vacuum by an axicon Gaussian laser beam, Phys. Rev. A 73, 043402 (2006); C. Varin and M. Piché, Relativistic attosecond electron pulses from a free-space laser-acceleration scheme, Phys. Rev. E 74, 045602 (2006); A. Sell and F. X. Kärtner, Attosecond electron bunches accelerated and compressed by radially polarized laser

  15. Magnesium diboride coated bulk niobium: a new approach to higher acceleration gradient

    NASA Astrophysics Data System (ADS)

    Tan, Teng; Wolak, M. A.; Xi, X. X.; Tajima, T.; Civale, L.

    2016-10-01

    Bulk niobium Superconducting Radio-Frequency cavities are a leading accelerator technology. Their performance is limited by the cavity loss and maximum acceleration gradient, which are negatively affected by vortex penetration into the superconductor when the peak magnetic field at the cavity wall surface exceeds the vortex penetration field (Hvp). It has been proposed that coating the inner wall of an SRF cavity with superconducting thin films increases Hvp. In this work, we utilized Nb ellipsoid to simulate an inverse SRF cavity and investigate the effect of coating it with magnesium diboride layer on the vortex penetration field. A significant enhancement of Hvp was observed. At 2.8 K, Hvp increased from 2100 Oe for an uncoated Nb ellipsoid to 2700 Oe for a Nb ellipsoid coated with ~200 nm thick MgB2 thin film. This finding creates a new route towards achieving higher acceleration gradient in SRF cavity accelerator beyond the theoretical limit of bulk Nb.

  16. Magnesium diboride coated bulk niobium: a new approach to higher acceleration gradient.

    PubMed

    Tan, Teng; Wolak, M A; Xi, X X; Tajima, T; Civale, L

    2016-10-24

    Bulk niobium Superconducting Radio-Frequency cavities are a leading accelerator technology. Their performance is limited by the cavity loss and maximum acceleration gradient, which are negatively affected by vortex penetration into the superconductor when the peak magnetic field at the cavity wall surface exceeds the vortex penetration field (H vp ). It has been proposed that coating the inner wall of an SRF cavity with superconducting thin films increases H vp . In this work, we utilized Nb ellipsoid to simulate an inverse SRF cavity and investigate the effect of coating it with magnesium diboride layer on the vortex penetration field. A significant enhancement of H vp was observed. At 2.8 K, H vp increased from 2100 Oe for an uncoated Nb ellipsoid to 2700 Oe for a Nb ellipsoid coated with ~200 nm thick MgB 2 thin film. This finding creates a new route towards achieving higher acceleration gradient in SRF cavity accelerator beyond the theoretical limit of bulk Nb.

  17. Magnesium diboride coated bulk niobium: a new approach to higher acceleration gradient

    NASA Astrophysics Data System (ADS)

    Civale, Leonardo; Tan, Teng; Wolak, M.; Xi, Xiaoxing; Tajima, Tsuyoshi

    Bulk niobium Superconducting Radio-Frequency cavities are a leading accelerator technology. Their performance is limited by the cavity loss and maximum acceleration gradient, which are negatively affected by vortex penetration into the superconductor when the peak magnetic field at the cavity wall surface exceeds the vortex penetration field (Hvp). It has been proposed that coating the inner wall of an SRF cavity with superconducting thin films increases Hvp. In this work, we utilized Nb ellipsoids to simulate an inverse SRF cavity and investigate the effect of coating it with magnesium diboride layer on the vortex penetration field. A significant enhancement of Hvp was observed. At 2.8 K, Hvp increased from 2100 Oe for an uncoated Nb ellipsoid to 2700 Oe for a Nb ellipsoid coated with 200 nm thick MgB2 thin film. This finding creates a new route towards achieving higher acceleration gradient in SRF cavity accelerator beyond the theoretical limit of bulk Nb.

  18. Magnesium diboride coated bulk niobium: a new approach to higher acceleration gradient

    PubMed Central

    Tan, Teng; Wolak, M. A.; Xi, X. X.; Tajima, T.; Civale, L.

    2016-01-01

    Bulk niobium Superconducting Radio-Frequency cavities are a leading accelerator technology. Their performance is limited by the cavity loss and maximum acceleration gradient, which are negatively affected by vortex penetration into the superconductor when the peak magnetic field at the cavity wall surface exceeds the vortex penetration field (Hvp). It has been proposed that coating the inner wall of an SRF cavity with superconducting thin films increases Hvp. In this work, we utilized Nb ellipsoid to simulate an inverse SRF cavity and investigate the effect of coating it with magnesium diboride layer on the vortex penetration field. A significant enhancement of Hvp was observed. At 2.8 K, Hvp increased from 2100 Oe for an uncoated Nb ellipsoid to 2700 Oe for a Nb ellipsoid coated with ~200 nm thick MgB2 thin film. This finding creates a new route towards achieving higher acceleration gradient in SRF cavity accelerator beyond the theoretical limit of bulk Nb. PMID:27775087

  19. Signature energetic analysis of accelerate electron beam after first acceleration station by accelerating stand of Joint Institute for Nuclear Research

    NASA Astrophysics Data System (ADS)

    Sledneva, A. S.; Kobets, V. V.

    2017-06-01

    The linear electron accelerator based on the LINAC - 800 accelerator imported from the Netherland is created at Joint Institute for Nuclear Research in the framework of the project on creation of the Testbed with an electron beam of a linear accelerator with an energy up to 250 MV. Currently two accelerator stations with a 60 MV energy of a beam are put in operation and the work is to put the beam through accelerating section of the third accelerator station. The electron beam with an energy of 23 MeV is used for testing the crystals (BaF2, CsI (native), and LYSO) in order to explore the opportunity to use them in particle detectors in experiments: Muon g-2, Mu2e, Comet, whose preparation requires a detailed study of the detectors properties such as their irradiation by the accelerator beams.

  20. Enabling Energy Efficiency (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

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

    Coltrin, Mike; Simmons, Jerry

    "Enabling Energy Efficiency" was submitted by the EFRC for Solid-State Lighting Science (SSLS) to the "Life at the Frontiers of Energy Research" video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. SSLS is directed by Mike Coltrin (Acting) and Jerry Simmons at Sandia National Laboratories, and is a partnership of scientists from eight institutions: Sandia National Laboratories (lead); California Institute of Technology; Los Alamos National Laboratoryl; University of New Mexico; Northwestern University; Philips Lumileds Lighting; University of Californiamore » Merced and Santa Barbara. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.« less

  1. Enabling Energy Efficiency (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema

    Coltrin, Mike (Acting Director, EFRC for Solid State Lighting Science); Simmons, Jerry; SSLS Staff

    2017-12-09

    'Enabling Energy Efficiency' was submitted by the EFRC for Solid-State Lighting Science (SSLS) to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. SSLS is directed by Mike Coltrin (Acting) and Jerry Simmons at Sandia National Laboratories, and is a partnership of scientists from eight institutions: Sandia National Laboratories (lead); California Institute of Technology; Los Alamos National Laboratory; University of Massachusetts, Lowell; University of New Mexico; Northwestern University; Philips Lumileds Lighting; and Rensselaer Polytechnic Institute. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.

  2. Electron acceleration by magnetic islands in a dynamically evolved coronal current sheet

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

    Zhang, Shaohua, E-mail: shzhang@mail.iggcas.ac.cn; Wang, Bin; Meng, Lifei

    2016-03-25

    This work simulated the electron acceleration by magnetic islands in a drastically evolved solar coronal current sheet via the combined 2.5-dimensional (2.5D) resistive Magnetohydrodynamics (MHD) and guiding-center approximation test-particle methods. With high magnetic Reynolds number of 105, the long–thin current sheet is evolved into a chain of magnetic islands, growing in size and coalescing with each other, due to tearing instability. The acceleration of electrons is studied in one typical phase when several large magnetic islands are formed. The results show that the electrons with an initial Maxwell distribution evolve into a heavy-tailed distribution and more than 20% of themore » electrons can be accelerated higher than 200 keV within 0.1 second and some of them can even be energized up to MeV ranges. The most energetic electrons have a tendency to be around the outer regions of the magnetic islands or to be located in the small secondary magnetic islands. We find that the acceleration and spatial distributions of the energetic electrons is caused by the trapping effect of the magnetic islands and the distributions of the parallel electric field E{sub p}.« less

  3. FERMILAB ACCELERATOR R&D PROGRAM TOWARDS INTENSITY FRONTIER ACCELERATORS : STATUS AND PROGRESS

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

    Shiltsev, Vladimir

    2016-11-15

    The 2014 P5 report indicated the accelerator-based neutrino and rare decay physics research as a centrepiece of the US domestic HEP program at Fermilab. Operation, upgrade and development of the accelerators for the near- term and longer-term particle physics program at the Intensity Frontier face formidable challenges. Here we discuss key elements of the accelerator physics and technology R&D program toward future multi-MW proton accelerators and present its status and progress. INTENSITY FRONTIER ACCELERATORS

  4. Minimal Invasive Left Ventricular Lead Repositioning is Safe and Effective in Distal Left Ventricular Lead Positions.

    PubMed

    Osztheimer, István; Szilágyi, Szabolcs; Pongor, Zsuzsanna; Zima, Endre; Molnár, Levente; Tahin, Tamás; Merkely, Béla; Gellér, László

    2017-05-01

    Treatment of left ventricular electrode dislocation and phrenic nerve stimulation remains an issue in the era of new electrode designs. Safety and efficacy of minimal invasive lead repositioning and pocket opening reposition procedures were evaluated between December 2005 and December 2012 at our center. Minimal invasive method was developed and widely utilized at our center to treat phrenic nerve stimulation. The distally positioned left ventricular lead is looped around by a deflectable catheter in the right atrium introduced from the femoral vein access and then pulled back. Coronary stent implantation was used afterwards for lead stabilization in some patients. 42 minimal invasive and 48 electrode repositions with pacemaker pocket opening were performed at 77 patients for left ventricular lead problems. Minimal invasive reposition could be carried out successfully in 69% of (29 patients) cases. Note that in 14.3% of the cases (six patients) minimal invasive procedures were acutely unsuccessful and crossover was necessary. In 16.6% of the cases (seven patients) lead issues were noted later during follow-up. Opening of the pocket could be carried out successfully in 81.2% (39 patients) and was unsuccessful acutely in 6.25% (three patients). Repeated dislocation was noticed, 12.5%, in this group (six patients). Complication during minimal invasive procedures was electrode injury in one case. Pocket openings were associated with several complications: atrial fibrillation, pericardial effusion, fever, hematoma, and right ventricular electrode dislodgement. Minimal invasive procedure-as the first line approach-is safe and feasible for left ventricular electrode repositioning in selected cases. © 2017 Wiley Periodicals, Inc.

  5. In-Flight Estimation of Center of Gravity Position Using All-Accelerometers

    PubMed Central

    Al-Rawashdeh, Yazan Mohammad; Elshafei, Moustafa; Al-Malki, Mohammad Fahad

    2014-01-01

    Changing the position of the Center of Gravity (CoG) for an aerial vehicle is a challenging part in navigation, and control of such vehicles. In this paper, an all-accelerometers-based inertial measurement unit is presented, with a proposed method for on-line estimation of the position of the CoG. The accelerometers' readings are used to find and correct the vehicle's angular velocity and acceleration using an Extended Kalman Filter. Next, the accelerometers' readings along with the estimated angular velocity and acceleration are used in an identification scheme to estimate the position of the CoG and the vehicle's linear acceleration. The estimated position of the CoG and motion measurements can then be used to update the control rules to achieve better trim conditions for the air vehicle. PMID:25244585

  6. In-flight estimation of center of gravity position using all-accelerometers.

    PubMed

    Al-Rawashdeh, Yazan Mohammad; Elshafei, Moustafa; Al-Malki, Mohammad Fahad

    2014-09-19

    Changing the position of the Center of Gravity (CoG) for an aerial vehicle is a challenging part in navigation, and control of such vehicles. In this paper, an all-accelerometers-based inertial measurement unit is presented, with a proposed method for on-line estimation of the position of the CoG. The accelerometers' readings are used to find and correct the vehicle's angular velocity and acceleration using an Extended Kalman Filter. Next, the accelerometers' readings along with the estimated angular velocity and acceleration are used in an identification scheme to estimate the position of the CoG and the vehicle's linear acceleration. The estimated position of the CoG and motion measurements can then be used to update the control rules to achieve better trim conditions for the air vehicle.

  7. Single particles accelerate final stages of capillary break-up

    NASA Astrophysics Data System (ADS)

    Lindner, Anke; Fiscina, Jorge Eduardo; Wagner, Christian

    2015-06-01

    Droplet formation of suspensions is present in many industrial and technological processes such as coating and food engineering. Whilst the finite-time singularity of the minimum neck diameter in capillary break-up of simple liquids can be described by well-known self-similarity solutions, the pinching of non-Brownian suspension depends in a complex way on the particle dynamics in the thinning thread. Here we focus on the very dilute regime where the filament contains only isolated beads to identify the physical mechanisms leading to the pronounced acceleration of the filament thinning observed. This accelerated regime is characterized by an asymmetric shape of the filament with an enhanced curvature that depends on the size and the spatial distribution of the particles within the capillary thread.

  8. Accelerated DNA Methylation Age: Associations with PTSD and Neural Integrity

    PubMed Central

    Wolf, Erika J.; Logue, Mark W.; Hayes, Jasmeet P.; Sadeh, Naomi; Schichman, Steven A.; Stone, Annjanette; Salat, David H.; Milberg, William; McGlinchey, Regina; Miller, Mark W.

    2015-01-01

    Background Accumulating evidence suggests that post traumatic stress disorder (PTSD) may accelerate cellular aging and lead to premature morbidity and neurocognitive decline. Methods This study evaluated associations between PTSD and DNA methylation (DNAm) age using recently developed algorithms of cellular age by Horvath (2013) and Hannum et al. (2013). These estimates reflect accelerated aging when they exceed chronological age. We also examined if accelerated cellular age manifested in degraded neural integrity, indexed via diffusion tensor imaging. Results Among 281 male and female veterans of the conflicts in Iraq and Afghanistan, DNAm age was strongly related to chronological age (rs ~.88). Lifetime PTSD severity was associated with Hannum DNAm age estimates residualized for chronological age (β = .13, p= .032). Advanced DNAm age was associated with reduced integrity in the genu of the corpus callosum (β = −.17, p= .009) and indirectly linked to poorer working memory performance via this region (indirect β = − .05, p= .029). Horvath DNAm age estimates were not associated with PTSD or neural integrity. Conclusions Results provide novel support for PTSD-related accelerated aging in DNAm and extend the evidence base of known DNAm age correlates to the domains of neural integrity and cognition. PMID:26447678

  9. Lead-Free Double-Base Propellant for the 2.75 Inch Rocket Motor

    NASA Technical Reports Server (NTRS)

    Magill, B. T.; Nauflett, G. W.; Furrow, K. W.

    2000-01-01

    The current MK 66 2.75 inch Rocket Motor double-base propellant contains the lead-based ballistic modifier LC-12-15 to achieve the desired plateau and mesa burning rate characteristics. The use of lead compounds poses a concern for the environment and for personal safety due to the metal's toxic nature when introduced into the atmosphere by propellant manufacture, rocket motor firing, and disposal. Copper beta-resorcylate (copper 2,4-di-hydroxy-benzoate) was successfully used in propellant as a simple modifier in the mid 1970's. This and other compounds have also been mixed with lead salts to obtain more beneficial ballistic results. Synthesized complexes of lead and copper compounds soon replaced the mixtures. The complexes incorporate the lead, copper lack of organic liquids, which allows for easier propellant processing. About ten years ago, the Indian Head Division, Naval Surface Warfare Center (NSWC), initiated an effort to develop a lead-free propellant for use in missile systems. Several lead-free propellant candidate formulations were developed. About five years ago, NSWC, in conjunction with Alliant Techsystems, Radford Army Ammunition Plant, continued ballistic modifier investigations. A four component ballistic modifier system without lead for double-base propellants that provide adequate plateau and mesa burn rate characteristics was developed and patented. The ballistic modifier's system contains bismuth subsalicylate, 1.5 percent; copper salicylate, 1.0 percent, copper stannate, 0.77 percent; and carbon black, 0.1 percent. Action time and impulse data obtained through multiple static firings indicate that the new lead-free double-base propellant, while not a match for NOSIH-AA-2, will be a very suitable replacement in the 2.75 inch Rocket Motor. Accelerated aging of the double-base propellant containing the lead-free ballistic modifier showed that it had a much higher rate of stabilizer depletion than the AA-2. A comprehensive study showed that an

  10. Neck forces and moments and head accelerations in side impact.

    PubMed

    Yoganandan, Narayan; Pintar, Frank A; Maiman, Dennis J; Philippens, Mat; Wismans, Jac

    2009-03-01

    Although side-impact sled studies have investigated chest, abdomen, and pelvic injury mechanics, determination of head accelerations and the associated neck forces and moments is very limited. The purpose of the present study was therefore to determine the temporal forces and moments at the upper neck region and head angular accelerations and angular velocities using postmortem human subjects (PMHS). Anthropometric data and X-rays were obtained, and the specimens were positioned upright on a custom-designed seat, rigidly fixed to the platform of the sled. PMHS were seated facing forward with the Frankfort plane horizontal, and legs were stretched parallel to the mid-sagittal plane. The normal curvature and alignment of the dorsal spine were maintained without initial torso rotation. A pyramid-shaped nine-accelerometer package was secured to the parietal-temporal region of the head. The test matrix consisted of groups A and B, representing the fully restrained torso condition, and groups C and D, representing the three-point belt-restrained torso condition. The change in velocity was 12.4 m/s for groups A and C, 17.9 m/s for group B, and 8.7 m/s for group D tests. Two specimens were tested in each group. Injuries were scored based on the Abbreviated Injury Scale. The head mass, center of gravity, and moment of inertia were determined for each specimen. Head accelerations and upper neck forces and moments were determined before head contact. Neck forces and moments and head angular accelerations and angular velocities are presented on a specimen-by-specimen basis. In addition, a summary of peak magnitudes of biomechanical data is provided because of their potential in serving as injury reference values characterizing head-neck biomechanics in side impacts. Though no skull fractures occurred, AIS 0 to 3 neck traumas were dependent on the impact velocity and restraint condition. Because specimen-specific head center of gravity and mass moment of inertia were determined

  11. Clean Energy Solutions Center Services (Chinese Translation)

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

    2016-03-01

    This is a Mandarin translation of the Clean Energy Solutions Center fact sheet. The Solutions Center offers no-cost expert policy assistance, webinars and training forums, clean energy policy reports, data, and tools provided in partnership with more than 35 leading international and regional clean energy organizations.

  12. Clean Energy Solutions Center Services (Vietnamese Translation)

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

    2016-03-01

    This is a Vietnamese translation of the Clean Energy Solutions Center fact sheet. The Solutions Center offers no-cost expert policy assistance, webinars and training forums, clean energy policy reports, data, and tools provided in partnership with more than 35 leading international and regional clean energy organizations.

  13. Clean Energy Solutions Center Services (French Translation)

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

    This is a French translation of the Clean Energy Solutions Center fact sheet. The Solutions Center offers no-cost expert policy assistance, webinars and training forums, clean energy policy reports, data, and tools provided in partnership with more than 35 leading international and regional clean energy organizations.

  14. Clean Energy Solutions Center Services (Arabic Translation)

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

    2016-03-01

    This is an Arabic translation of the Clean Energy Solutions Center fact sheet. The Solutions Center offers no-cost expert policy assistance, webinars and training forums, clean energy policy reports, data, and tools provided in partnership with more than 35 leading international and regional clean energy organizations.

  15. Plasma Acceleration by Rotating Magnetic Field Method using Helicon Source

    NASA Astrophysics Data System (ADS)

    Furukawa, Takeru; Shimura, Kaichi; Kuwahara, Daisuke; Shinohara, Shunjiro

    2017-10-01

    Electrodeless plasma thrusters are very promising due to no electrode damage, leading to realize further deep space exploration. As one of the important proposals, we have been concentrating on Rotating Magnetic Field (RMF) acceleration method. High-dense plasma (up to 1013 cm-3) can be generated by using a radio frequency (rf) external antenna, and also accelerated by an antenna wound around outside of a discharge tube. In this scheme, thrust increment is achieved by the axial Lorentz force caused by non linear effects. RMF penetration condition into plasma can be more satisfied than our previous experiment, by increasing RMF coil current and decreasing the RMF frequency, causing higher thrust and fuel efficiency. Measurements of AC RMF component s have been conducted to investigate the acceleration mechanism and the field penetration experimentally. This study has been partially supported by Grant-in-Aid for Scientific Research (B: 17H02995) from the Japan Society for the Promotion of Science.

  16. Magnetic field, reconnection, and particle acceleration in extragalactic jets

    NASA Technical Reports Server (NTRS)

    Romanova, M. M.; Lovelace, R. V. E.

    1992-01-01

    Extra-galactic radio jets are investigated theoretically taking into account that the jet magnetic field is dragged out from the central rotating source by the jet flow. Thus, magnetohydrodynamic models of jets are considered with zero net poloidal current and flux, and consequently a predominantly toroidal magnetic field. The magnetic field naturally has a cylindrical neutral layer. Collisionless reconnection of the magnetic field in the vicinity of the neutral layer acts to generate a non-axisymmetric radial magnetic field. In turn, axial shear-stretching of reconnected toroidal field gives rise to a significant axial magnetic field if the flow energy-density is larger than the energy-density of the magnetic field. This can lead to jets with an apparent longitudinal magnetic field as observed in the Fanaroff-Riley class II jets. In the opposite limit, where the field energy-density is large, the field remains mainly toroidal as observed in Fanaroff-Riley class I jets. Driven collisionless reconnection at neutral layers may lead to acceleration of electrons to relativistic energies in the weak electrostatic field of the neutral layer. A simple model is discussed for particle acceleration at neutral layers in electron/positron and electron/proton plasmas.

  17. The lead and lead-acid battery industries during 2002 and 2007 in China

    NASA Astrophysics Data System (ADS)

    Chen, H. Y.; Li, A. J.; Finlow, D. E.

    In the past 15 years, the center of the international lead market has shifted to China. China has become the largest producer of raw and refined lead, plus the largest consumer. This paper reviews the status of the lead and lead-acid battery industries in China, including lead mining, lead refining, secondary lead production, the lead-acid battery industry, new opportunities for lead-acid batteries, and the environmental problems associated with lead and lead-acid batteries. The output of raw and refined lead has increased annually in China, and now accounts for more than 30% of the world total. As a result of a change in the Chinese government's policy regarding the export of lead, plus an increase in the price of lead, the profits of Chinese lead manufacturers were significantly reduced, the trade deficit of the Chinese lead industry increased, the operating rates of lead smelter enterprises greatly reduced, and some small enterprises were forced to shut down. At the present time, an increasing number of enterprises have begun to produce secondary lead, and the scale of production has expanded from tens of tons to tens of thousands of tons. In 2006, the output of secondary lead in China reached 700,000 tons, but outdated technology and equipment limited development of the secondary lead industry. Because of serious pollution problems, raw material shortages, and fierce price competition in the battery market, changes in the development of the lead-acid battery industry have been dramatic; approximately one thousand medium-sized and small lead-acid battery producers have been closed in the past 3 years. The output of large lead-acid battery enterprises has not been reduced, however, as a result of their manufacturing technology and equipment being comparable to those in other advanced industrial countries. In China, the flourishing development of electric bicycles, electric tricycles, and photovoltaic energy systems should provide ongoing opportunities for the

  18. 77 FR 59200 - Center for Scientific Review; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-26

    ... Panel; PAR 10-018: Accelerating the Pace of Drug Abuse Research Using Existing Epidemiology, Prevention, and Treatment Research Data. Date: October 24, 2012. Time: 2 p.m. to 4 p.m. Agenda: To review and...: Center for Scientific Review Special Emphasis Panel; PA:12-006: Academic Research Enhancement Award...

  19. 78 FR 66018 - Center for Scientific Review; Notice of Closed Meetings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ... Panel, Accelerator Mass Spectrometry Facility. Date: December 2-3, 2013. Time: 8:00 a.m. to 6:00 p.m... DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health Center for Scientific Review... personal privacy. Name of Committee: AIDS and Related Research Integrated Review Group, AIDS-associated...

  20. Laser-Driven Ion Acceleration from Plasma Micro-Channel Targets

    PubMed Central

    Zou, D. B.; Pukhov, A.; Yi, L. Q.; Zhou, H. B.; Yu, T. P.; Yin, Y.; Shao, F. Q.

    2017-01-01

    Efficient energy boost of the laser-accelerated ions is critical for their applications in biomedical and hadron research. Achiev-able energies continue to rise, with currently highest energies, allowing access to medical therapy energy windows. Here, a new regime of simultaneous acceleration of ~100 MeV protons and multi-100 MeV carbon-ions from plasma micro-channel targets is proposed by using a ~1020 W/cm2 modest intensity laser pulse. It is found that two trains of overdense electron bunches are dragged out from the micro-channel and effectively accelerated by the longitudinal electric-field excited in the plasma channel. With the optimized channel size, these “superponderomotive” energetic electrons can be focused on the front surface of the attached plastic substrate. The much intense sheath electric-field is formed on the rear side, leading to up to ~10-fold ionic energy increase compared to the simple planar geometry. The analytical prediction of the optimal channel size and ion maximum energies is derived, which shows good agreement with the particle-in-cell simulations. PMID:28218247

  1. Laser-Driven Ion Acceleration from Plasma Micro-Channel Targets

    NASA Astrophysics Data System (ADS)

    Zou, D. B.; Pukhov, A.; Yi, L. Q.; Zhou, H. B.; Yu, T. P.; Yin, Y.; Shao, F. Q.

    2017-02-01

    Efficient energy boost of the laser-accelerated ions is critical for their applications in biomedical and hadron research. Achiev-able energies continue to rise, with currently highest energies, allowing access to medical therapy energy windows. Here, a new regime of simultaneous acceleration of ~100 MeV protons and multi-100 MeV carbon-ions from plasma micro-channel targets is proposed by using a ~1020 W/cm2 modest intensity laser pulse. It is found that two trains of overdense electron bunches are dragged out from the micro-channel and effectively accelerated by the longitudinal electric-field excited in the plasma channel. With the optimized channel size, these “superponderomotive” energetic electrons can be focused on the front surface of the attached plastic substrate. The much intense sheath electric-field is formed on the rear side, leading to up to ~10-fold ionic energy increase compared to the simple planar geometry. The analytical prediction of the optimal channel size and ion maximum energies is derived, which shows good agreement with the particle-in-cell simulations.

  2. Methods for measuring plating thicknesses on TAB lead frames

    NASA Technical Reports Server (NTRS)

    Hagen, M. P.

    1977-01-01

    Plating three layer tape lead frames, used for tape automated bonding, offers a challenge to the electroplater because of nonuniform topography. Each lead frame contains large (typically .05 x. .05 inch) flat test pads located around the perimeter of the frame. These test pads are electrically connected to the bondable lead frame fingers which extend into an area in the center of the frame called the feature hole. The feature hole exposes these fingers to plating on all sides, while the test pads are exposed on only one side. In addition, the fingers are small in cross section (typically .003 x .0015 inches). Recent thickness measurements indicate that plating around the lead frame fingers is nearly twice as thick as that on test pad areas. Procedures and equipment were developed for measuring the thickness of the deposited material. Discussion was centered on the data obtained using the various measurement techniques and equipment.

  3. Accelerated test design

    NASA Technical Reports Server (NTRS)

    Mcdermott, P. P.

    1980-01-01

    The design of an accelerated life test program for electric batteries is discussed. A number of observations and suggestions on the procedures and objectives for conducting an accelerated life test program are presented. Equations based on nonlinear regression analysis for predicting the accelerated life test parameters are discussed.

  4. Vice President Pence Leads National Space Council Meeting, Tours Kennedy Space Center

    NASA Image and Video Library

    2018-02-20

    Vice President Mike Pence arrived at Kennedy Space Center in Florida on Tuesday, Feb. 20 at 5:10 p.m. aboard Air Force Two. The Vice President was greeted by Robert Lightfoot, acting NASA Administrator and Brig. Gen. Wayne Monteith, commander, 45th Space Wing. After arrival, the vice president toured commercial partner United Launch Alliance’s facility at Cape Canaveral Air Force Station adjacent to Kennedy. He also toured Blue Origin’s new rocket facility located at nearby Exploration Park. On Feb. 21, Vice President Mike Pence led a National Space Council meeting inside NASA Kennedy Space Center’s Space Station Processing Facility. This second meeting of the council, called, “Moon, Mars, and Worlds Beyond: Winning the Next Frontier,” included testimonials from leaders in the civil, commercial, and national security sectors about the importance of the United States’ space enterprise. Vice President Pence concluded his visit with a tour of Kennedy Space Center, which included stops at the Boeing Commercial Crew and Cargo Processing Facility, and SpaceX Launch Complex 39A.

  5. SU-E-J-110: TG 51 Dosimetry : With Or Without Lead

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

    Shah, M

    TG-51 Dosimetry: With or Without Lead. Purpose: In this project, an analytical method has been introduced for adjustment of the TG-51 recommended KQ in order to produce accurate dosimetric data for high energy photons without the lead foil. Methods: These investigations were performed using a 30 cm × 30 cm × 30 cm CIVCO water tank, A12 EXRADIN Water proof Farmer Chamber, a Standard Imaging MAX 4000 electrometer, and 1 mm thick lead foil from Standard Imaging. Complete TG-51 was performed every month with and without lead. The results were analyzed and an analytical model has been developed for comparingmore » the values of KQ. TG-51 Table I was used to obtain KQ values. Results: The dosimetric evaluations were obtained for Varian Linear accelerators Model 21ix and 21ex. These results indicates that the measured data with lead foil in place as recommended by TG-51 is in excellent agreement (within 0.1%) with the calculated data obtained by the new model, from our dosimetry data without-lead. If equation 15 of the TG-51 report is used without any adjustments, it will lead to differences of about 1.6 % (on the average) in relative data which will Resultin differences of about 0.3 % (on the average) in the KQ Values. The KQ value for 18 MV obtained consistently with the equation of TG-51 “with lead” and “without lead” were 0.971 and 0.974, respectively. The 0.3 % higher results for KQ without lead eventually will lead to 0.3% larger output. However, by considering this model the KQ value was found to be 0.971 for dosimetry without lead. Conclusion: The analytical model that was introduced in this project was able to reproduce the dosimetric data of the high energy linear accelerators to within 0.1% without the use of the lead foil.« less

  6. Clean Energy Solutions Center Services (Portuguese Translation)

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

    This is a Portuguese translation of the Clean Energy Solutions Center Services fact sheet. The Solutions Center offers no-cost expert policy assistance, webinars and training forums, clean energy policy reports, data, and tools provided in partnership with more than 35 leading international and regional clean energy organizations.

  7. Accelerating proof of concept for small molecule drugs using solid-state chemistry.

    PubMed

    Byrn, Stephen R; Zografi, George; Chen, Xiaoming Sean

    2010-09-01

    In this perspective we have shown that the process of "proof of concept" (POC) in the early part of drug development can be greatly accelerated by close attention to the underlying solid-state chemistry (SSC) of a new chemical entity. POC seeks data that provide confidence in the therapeutic activity and safety of a new chemical entity, which can rapidly lead to a key "GO/NO-GO" decision point for further development. Due to the high cost of the development of new chemical entities and the current low overall productivity of obtaining successful candidates, the pharmaceutical industry is being required to develop accelerated POC strategies. The success of accelerated approaches to POC depends on a full understanding of the SSC of drugs in relation to solubility and stability. Dissolution-limited absorption due to poor solubility of drug substances is particularly important because it can lead to low exposure in animals and undesired bioavailability in humans. Choosing a desirable solid form with sufficient solubility and acceptable stability is essential in developing formulations for POC with superior quality. In this perspective we present an approach that utilizes SSC as part of a novel 2-year development strategy for reaching the pivotal clinical trial stage of development.

  8. Plasma inverse transition acceleration

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

    Xie, Ming

    It can be proved fundamentally from the reciprocity theorem with which the electromagnetism is endowed that corresponding to each spontaneous process of radiation by a charged particle there is an inverse process which defines a unique acceleration mechanism, from Cherenkov radiation to inverse Cherenkov acceleration (ICA) [1], from Smith-Purcell radiation to inverse Smith-Purcell acceleration (ISPA) [2], and from undulator radiation to inverse undulator acceleration (IUA) [3]. There is no exception. Yet, for nearly 30 years after each of the aforementioned inverse processes has been clarified for laser acceleration, inverse transition acceleration (ITA), despite speculation [4], has remained the least understood,more » and above all, no practical implementation of ITA has been found, until now. Unlike all its counterparts in which phase synchronism is established one way or the other such that a particle can continuously gain energy from an acceleration wave, the ITA to be discussed here, termed plasma inverse transition acceleration (PITA), operates under fundamentally different principle. As a result, the discovery of PITA has been delayed for decades, waiting for a conceptual breakthrough in accelerator physics: the principle of alternating gradient acceleration [5, 6, 7, 8, 9, 10]. In fact, PITA was invented [7, 8] as one of several realizations of the new principle.« less

  9. Multipactor Physics, Acceleration, and Breakdown in Dielectric-Loaded Accelerating Structures

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

    Fischer, Richard P.; Gold, Steven H.

    2016-07-01

    The objective of this 3-year program is to study the physics issues associated with rf acceleration in dielectric-loaded accelerating (DLA) structures, with a focus on the key issue of multipactor loading, which has been found to cause very significant rf power loss in DLA structures whenever the rf pulsewidth exceeds the multipactor risetime (~10 ns). The experiments are carried out in the X-band magnicon laboratory at the Naval Research Laboratory (NRL) in collaboration with Argonne National Laboratory (ANL) and Euclid Techlabs LLC, who develop the test structures with support from the DoE SBIR program. There are two main elements inmore » the research program: (1) high-power tests of DLA structures using the magnicon output (20 MW @11.4 GHz), and (2) tests of electron acceleration in DLA structures using relativistic electrons from a compact X-band accelerator. The work during this period has focused on a study of the use of an axial magnetic field to suppress multipactor in DLA structures, with several new high power tests carried out at NRL, and on preparation of the accelerator for the electron acceleration experiments.« less

  10. Induction linear accelerators

    NASA Astrophysics Data System (ADS)

    Birx, Daniel

    1992-03-01

    Among the family of particle accelerators, the Induction Linear Accelerator is the best suited for the acceleration of high current electron beams. Because the electromagnetic radiation used to accelerate the electron beam is not stored in the cavities but is supplied by transmission lines during the beam pulse it is possible to utilize very low Q (typically<10) structures and very large beam pipes. This combination increases the beam breakup limited maximum currents to of order kiloamperes. The micropulse lengths of these machines are measured in 10's of nanoseconds and duty factors as high as 10-4 have been achieved. Until recently the major problem with these machines has been associated with the pulse power drive. Beam currents of kiloamperes and accelerating potentials of megavolts require peak power drives of gigawatts since no energy is stored in the structure. The marriage of liner accelerator technology and nonlinear magnetic compressors has produced some unique capabilities. It now appears possible to produce electron beams with average currents measured in amperes, peak currents in kiloamperes and gradients exceeding 1 MeV/meter, with power efficiencies approaching 50%. The nonlinear magnetic compression technology has replaced the spark gap drivers used on earlier accelerators with state-of-the-art all-solid-state SCR commutated compression chains. The reliability of these machines is now approaching 1010 shot MTBF. In the following paper we will briefly review the historical development of induction linear accelerators and then discuss the design considerations.

  11. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  12. Schooling in Times of Acceleration

    ERIC Educational Resources Information Center

    Buddeberg, Magdalena; Hornberg, Sabine

    2017-01-01

    Modern societies are characterised by forms of acceleration, which influence social processes. Sociologist Hartmut Rosa has systematised temporal structures by focusing on three categories of social acceleration: technical acceleration, acceleration of social change, and acceleration of the pace of life. All three processes of acceleration are…

  13. Center for Cancer Genomics | Office of Cancer Genomics

    Cancer.gov

    The Center for Cancer Genomics (CCG) was established to unify the National Cancer Institute's activities in cancer genomics, with the goal of advancing genomics research and translating findings into the clinic to improve the precise diagnosis and treatment of cancers. In addition to promoting genomic sequencing approaches, CCG aims to accelerate structural, functional and computational research to explore cancer mechanisms, discover new cancer targets, and develop new therapeutics.

  14. Moving from Petroleum to Plants to Energize our World (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

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

    McCann, Maureen; Yohe, Sara

    "Moving from Petroleum to Plants to Energize our World" was submitted by the Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio) to the "Life at the Frontiers of Energy Research" video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. C3Bio, an EFRC directed by Maureen McCann at Purdue University is a partnership between five institutions: Purdue (lead), National Renewable Energy Laboratory, Northeastern University, University of California Santa Barbara and the University of Tennessee. The Office ofmore » Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.« less

  15. Moving from Petroleum to Plants to Energize our World (A "Life at the Frontiers of Energy Research" contest entry from the 2011 Energy Frontier Research Centers (EFRCs) Summit and Forum)

    ScienceCinema

    McCann, Maureen (Director, Center for Direct Catalytic Conversion of Biomass to Biofuels); C3Bio Staff

    2017-12-09

    'Moving from Petroleum to Plants to Energize our World' was submitted by the Center for Direct Catalytic Conversion of Biomass to Biofuels (C3Bio) to the 'Life at the Frontiers of Energy Research' video contest at the 2011 Science for Our Nation's Energy Future: Energy Frontier Research Centers (EFRCs) Summit and Forum. Twenty-six EFRCs created short videos to highlight their mission and their work. C3Bio, an EFRC directed by Maureen McCann at Purdue University is a partnership between five institutions: Purdue (lead), Argonne National Laboratory, National Renewable Energy Laboratory, Northeastern University, and the University of Tennessee. The Office of Basic Energy Sciences in the U.S. Department of Energy's Office of Science established the 46 Energy Frontier Research Centers (EFRCs) in 2009. These collaboratively-organized centers conduct fundamental research focused on 'grand challenges' and use-inspired 'basic research needs' recently identified in major strategic planning efforts by the scientific community. The overall purpose is to accelerate scientific progress toward meeting the nation's critical energy challenges.

  16. Radiation from Accelerating Electric Charges: The Third Derivative of Position

    NASA Astrophysics Data System (ADS)

    Butterworth, Edward

    2010-03-01

    While some textbooks appear to suggest that acceleration of an electric charge is both a necessary and sufficient cause for the generation of electromagnetic radiation, the question has in fact had an intricate and involved history. In particular, the acceleration of a charge in hyperbolic motion, the behavior of a charge supported against a gravitational force (and its implications for the Equivalence Principle), and a charge accelerated by a workless constraint have been the subject of repeated investigation. The present paper examines specifically the manner in which the third derivative of position enters into the equations of motion, and the implications this has for the emission of radiation. Plass opens his review article with the statement that ``A fundamental property of all charged particles is that electromagnetic energy is radiated whenever they are accelerated'' (Plass 1961; emphasis mine). His treatment of the equations of motion, however, emphasizes the importance of the occurrence of the third derivative of position therein, present in linear motion only when the rate of acceleration is increasing or decreasing. There appears to be general agreement that the presence of a nonzero third derivative indicates that this charge is radiating; but does its absence preclude radiation? This question leads back to the issues of charges accelerated by a uniform gravitational field. We will examine the equations of motion as presented in Fulton & Rohrlich (1960), Plass (1961), Barut (1964), Teitelboim (1970) and Mo & Papas (1971) in the light of more recent literature in an attempt to clarify this question.

  17. Can superhorizon cosmological perturbations explain the acceleration of the universe?

    NASA Astrophysics Data System (ADS)

    Hirata, Christopher M.; Seljak, Uroš

    2005-10-01

    We investigate the recent suggestions by Barausse et al. and Kolb et al. that the acceleration of the universe could be explained by large superhorizon fluctuations generated by inflation. We show that no acceleration can be produced by this mechanism. We begin by showing how the application of Raychaudhuri equation to inhomogeneous cosmologies results in several “no go” theorems for accelerated expansion. Next we derive an exact solution for a specific case of initial perturbations, for which application of the Kolb et al. expressions leads to an acceleration, while the exact solution reveals that no acceleration is present. We show that the discrepancy can be traced to higher-order terms that were dropped in the Kolb et al. analysis. We proceed with the analysis of initial value formulation of general relativity to argue that causality severely limits what observable effects can be derived from superhorizon perturbations. By constructing a Riemann normal coordinate system on initial slice we show that no infrared divergence terms arise in this coordinate system. Thus any divergences found previously can be eliminated by a local rescaling of coordinates and are unobservable. We perform an explicit analysis of the variance of the deceleration parameter for the case of single-field inflation using usual coordinates and show that the infrared-divergent terms found by Barausse et al. and Kolb et al. cancel against several additional terms not considered in their analysis. Finally, we argue that introducing isocurvature perturbations does not alter our conclusion that the accelerating expansion of the universe cannot be explained by superhorizon modes.

  18. Monitoring Traffic Information with a Developed Acceleration Sensing Node.

    PubMed

    Ye, Zhoujing; Wang, Linbing; Xu, Wen; Gao, Zhifei; Yan, Guannan

    2017-12-05

    In this paper, an acceleration sensing node for pavement vibration was developed to monitor traffic information, including vehicle speed, vehicle types, and traffic flow, where a hardware design with low energy consumption and node encapsulation could be accomplished. The service performance of the sensing node was evaluated, by methods including waterproof test, compression test, sensing performance analysis, and comparison test. The results demonstrate that the sensing node is low in energy consumption, high in strength, IPX8 waterproof, and high in sensitivity and resolution. These characteristics can be applied to practical road environments. Two sensing nodes were spaced apart in the direction of travelling. In the experiment, three types of vehicles passed by the monitoring points at several different speeds and values of d (the distance between the sensor and the nearest tire center line). Based on cross-correlation with kernel pre-smoothing, a calculation method was applied to process the raw data. New algorithms for traffic flow, speed, and axle length were proposed. Finally, the effects of vehicle speed, vehicle weight, and d value on acceleration amplitude were statistically evaluated. It was found that the acceleration sensing node can be used for traffic flow, vehicle speed, and other types of monitoring.

  19. Monitoring Traffic Information with a Developed Acceleration Sensing Node

    PubMed Central

    Ye, Zhoujing; Wang, Linbing; Xu, Wen; Gao, Zhifei; Yan, Guannan

    2017-01-01

    In this paper, an acceleration sensing node for pavement vibration was developed to monitor traffic information, including vehicle speed, vehicle types, and traffic flow, where a hardware design with low energy consumption and node encapsulation could be accomplished. The service performance of the sensing node was evaluated, by methods including waterproof test, compression test, sensing performance analysis, and comparison test. The results demonstrate that the sensing node is low in energy consumption, high in strength, IPX8 waterproof, and high in sensitivity and resolution. These characteristics can be applied to practical road environments. Two sensing nodes were spaced apart in the direction of travelling. In the experiment, three types of vehicles passed by the monitoring points at several different speeds and values of d (the distance between the sensor and the nearest tire center line). Based on cross-correlation with kernel pre-smoothing, a calculation method was applied to process the raw data. New algorithms for traffic flow, speed, and axle length were proposed. Finally, the effects of vehicle speed, vehicle weight, and d value on acceleration amplitude were statistically evaluated. It was found that the acceleration sensing node can be used for traffic flow, vehicle speed, and other types of monitoring. PMID:29206169

  20. KENNEDY SPACE CENTER, FLA. - Dryden Flight Research Center Director Kevin Peterson talks about One NASA during the rollout of the Agency initiative at KSC. The event was held at the IMAX Theater® where NASA leaders discussed One NASA with selected employees. Explaining how their respective centers contribute to One NASA, along with Peterson, were KSC Director Jim Kennedy, James Jennings, NASA’s associate deputy administrator for institutions and asset management; Ed Weiler, associate administrator for Space Science; Kevin Peterson, Dryden Flight Research Center director; incoming KSC Deputy Director Woodrow Whitlow; and implementation team lead Johnny Stevenson. Glenn Research Center Director Dr. Julian Earls gave a motivational speech during the luncheon held at the Visitor Complex Debus Conference Center.

    NASA Image and Video Library

    2003-08-20

    KENNEDY SPACE CENTER, FLA. - Dryden Flight Research Center Director Kevin Peterson talks about One NASA during the rollout of the Agency initiative at KSC. The event was held at the IMAX Theater® where NASA leaders discussed One NASA with selected employees. Explaining how their respective centers contribute to One NASA, along with Peterson, were KSC Director Jim Kennedy, James Jennings, NASA’s associate deputy administrator for institutions and asset management; Ed Weiler, associate administrator for Space Science; Kevin Peterson, Dryden Flight Research Center director; incoming KSC Deputy Director Woodrow Whitlow; and implementation team lead Johnny Stevenson. Glenn Research Center Director Dr. Julian Earls gave a motivational speech during the luncheon held at the Visitor Complex Debus Conference Center.

  1. Kinetic Simulations of Plasma Energization and Particle Acceleration in Interacting Magnetic Flux Ropes

    NASA Astrophysics Data System (ADS)

    Du, S.; Guo, F.; Zank, G. P.; Li, X.; Stanier, A.

    2017-12-01

    The interaction between magnetic flux ropes has been suggested as a process that leads to efficient plasma energization and particle acceleration (e.g., Drake et al. 2013; Zank et al. 2014). However, the underlying plasma dynamics and acceleration mechanisms are subject to examination of numerical simulations. As a first step of this effort, we carry out 2D fully kinetic simulations using the VPIC code to study the plasma energization and particle acceleration during coalescence of two magnetic flux ropes. Our analysis shows that the reconnection electric field and compression effect are important in plasma energization. The results may help understand the energization process associated with magnetic flux ropes frequently observed in the solar wind near the heliospheric current sheet.

  2. Fission-Fusion: A new reaction mechanism for nuclear astrophysics based on laser-ion acceleration

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

    Thirolf, P. G.; Gross, M.; Allinger, K.

    We propose to produce neutron-rich nuclei in the range of the astrophysical r-process around the waiting point N = 126 by fissioning a dense laser-accelerated thorium ion bunch in a thorium target (covered by a CH{sub 2} layer), where the light fission fragments of the beam fuse with the light fission fragments of the target. Via the 'hole-boring' mode of laser Radiation Pressure Acceleration using a high-intensity, short pulse laser, very efficiently bunches of {sup 232}Th with solid-state density can be generated from a Th target and a deuterated CD{sub 2} foil, both forming the production target assembly. Laser-accelerated Thmore » ions with about 7 MeV/u will pass through a thin CH{sub 2} layer placed in front of a thicker second Th foil (both forming the reaction target) closely behind the production target and disintegrate into light and heavy fission fragments. In addition, light ions (d,C) from the CD{sub 2} layer of the production target will be accelerated as well, inducing the fission process of {sup 232}Th also in the second Th layer. The laser-accelerated ion bunches with solid-state density, which are about 10{sup 14} times more dense than classically accelerated ion bunches, allow for a high probability that generated fission products can fuse again. The high ion beam density may lead to a strong collective modification of the stopping power, leading to significant range and thus yield enhancement. Using a high-intensity laser as envisaged for the ELI-Nuclear Physics project in Bucharest (ELI-NP), order-of-magnitude estimates promise a fusion yield of about 10{sup 3} ions per laser pulse in the mass range of A = 180-190, thus enabling to approach the r-process waiting point at N = 126.« less

  3. Smartphone application for mechanical quality assurance of medical linear accelerators

    NASA Astrophysics Data System (ADS)

    Kim, Hwiyoung; Lee, Hyunseok; In Park, Jong; Choi, Chang Heon; Park, So-Yeon; Kim, Hee Jung; Kim, Young Suk; Ye, Sung-Joon

    2017-06-01

    Mechanical quality assurance (QA) of medical linear accelerators consists of time-consuming and human-error-prone procedures. We developed a smartphone application system for mechanical QA. The system consists of two smartphones: one attached to a gantry for obtaining real-time information on the mechanical parameters of the medical linear accelerator, and another displaying real-time information via a Bluetooth connection with the former. Motion sensors embedded in the smartphone were used to measure gantry and collimator rotations. Images taken by the smartphone’s high-resolution camera were processed to evaluate accuracies of jaw-positioning, crosshair centering and source-to-surface distance (SSD). The application was developed using Android software development kit and OpenCV library. The accuracy and precision of the system was validated against an optical rotation stage and digital calipers, prior to routine QA measurements of five medical linear accelerators. The system accuracy and precision in measuring angles and lengths were determined to be 0.05  ±  0.05° and 0.25  ±  0.14 mm, respectively. The mean absolute errors (MAEs) in QA measurements of gantry and collimator rotation were 0.05  ±  0.04° and 0.05  ±  0.04°, respectively. The MAE in QA measurements of light field was 0.39  ±  0.36 mm. The MAEs in QA measurements of crosshair centering and SSD were 0.40  ±  0.35 mm and 0.41  ±  0.32 mm, respectively. In conclusion, most routine mechanical QA procedures could be performed using the smartphone application system with improved precision and within a shorter time-frame, while eliminating potential human errors.

  4. Smartphone application for mechanical quality assurance of medical linear accelerators.

    PubMed

    Kim, Hwiyoung; Lee, Hyunseok; Park, Jong In; Choi, Chang Heon; Park, So-Yeon; Kim, Hee Jung; Kim, Young Suk; Ye, Sung-Joon

    2017-06-07

    Mechanical quality assurance (QA) of medical linear accelerators consists of time-consuming and human-error-prone procedures. We developed a smartphone application system for mechanical QA. The system consists of two smartphones: one attached to a gantry for obtaining real-time information on the mechanical parameters of the medical linear accelerator, and another displaying real-time information via a Bluetooth connection with the former. Motion sensors embedded in the smartphone were used to measure gantry and collimator rotations. Images taken by the smartphone's high-resolution camera were processed to evaluate accuracies of jaw-positioning, crosshair centering and source-to-surface distance (SSD). The application was developed using Android software development kit and OpenCV library. The accuracy and precision of the system was validated against an optical rotation stage and digital calipers, prior to routine QA measurements of five medical linear accelerators. The system accuracy and precision in measuring angles and lengths were determined to be 0.05  ±  0.05° and 0.25  ±  0.14 mm, respectively. The mean absolute errors (MAEs) in QA measurements of gantry and collimator rotation were 0.05  ±  0.04° and 0.05  ±  0.04°, respectively. The MAE in QA measurements of light field was 0.39  ±  0.36 mm. The MAEs in QA measurements of crosshair centering and SSD were 0.40  ±  0.35 mm and 0.41  ±  0.32 mm, respectively. In conclusion, most routine mechanical QA procedures could be performed using the smartphone application system with improved precision and within a shorter time-frame, while eliminating potential human errors.

  5. Application of real-time digitization techniques in beam measurement for accelerators

    NASA Astrophysics Data System (ADS)

    Zhao, Lei; Zhan, Lin-Song; Gao, Xing-Shun; Liu, Shu-Bin; An, Qi

    2016-04-01

    Beam measurement is very important for accelerators. In this paper, modern digital beam measurement techniques based on IQ (In-phase & Quadrature-phase) analysis are discussed. Based on this method and high-speed high-resolution analog-to-digital conversion, we have completed three beam measurement electronics systems designed for the China Spallation Neutron Source (CSNS), Shanghai Synchrotron Radiation Facility (SSRF), and Accelerator Driven Sub-critical system (ADS). Core techniques of hardware design and real-time system calibration are discussed, and performance test results of these three instruments are also presented. Supported by National Natural Science Foundation of China (11205153, 10875119), Knowledge Innovation Program of the Chinese Academy of Sciences (KJCX2-YW-N27), and the Fundamental Research Funds for the Central Universities (WK2030040029),and the CAS Center for Excellence in Particle Physics (CCEPP).

  6. Efficient modeling of laser-plasma accelerator staging experiments using INF&RNO

    NASA Astrophysics Data System (ADS)

    Benedetti, C.; Schroeder, C. B.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.

    2017-03-01

    The computational framework INF&RNO (INtegrated Fluid & paRticle simulatioN cOde) allows for fast and accurate modeling, in 2D cylindrical geometry, of several aspects of laser-plasma accelerator physics. In this paper, we present some of the new features of the code, including the quasistatic Particle-In-Cell (PIC)/fluid modality, and describe using different computational grids and time steps for the laser envelope and the plasma wake. These and other features allow for a speedup of several orders of magnitude compared to standard full 3D PIC simulations while still retaining physical fidelity. INF&RNO is used to support the experimental activity at the BELLA Center, and we will present an example of the application of the code to the laser-plasma accelerator staging experiment.

  7. Mass center estimation of a drag-free satellite

    NASA Technical Reports Server (NTRS)

    Sanz Fernandez De Cordova, S.; Debra, D. B.

    1975-01-01

    The mass center location of a spinning drag-free satellite can be estimated because there is control required to accelerate the mass center along the axis of spin as long as there is some nutation in the spinning motion. Linear and nonlinear models are compared and observability discussed. Online estimation fails when nutation is damped so an offline mechanization is proposed. A new sensor has been designed to permit greater relative motion than was possible on the drag-free satellite flown in 1972 (JH-1). Experimental laboratory results using a spinning vehicle with the new sensor mounted 30 cm from a spherical air bearing support are presented which confirm earlier simulation results.

  8. ACCELERATION AND THE GIFTED.

    ERIC Educational Resources Information Center

    GIBSON, ARTHUR R.; STEPHANS, THOMAS M.

    ACCELERATION OF PUPILS AND SUBJECTS IS CONSIDERED A MEANS OF EDUCATING THE ACADEMICALLY GIFTED STUDENT. FIVE INTRODUCTORY ARTICLES PROVIDE A FRAMEWORK FOR THINKING ABOUT ACCELERATION. FIVE PROJECT REPORTS OF ACCELERATED PROGRAMS IN OHIO ARE INCLUDED. ACCELERATION IS NOW BEING REGARDED MORE FAVORABLY THAN FORMERLY, BECAUSE METHODS HAVE BEEN…

  9. ELECTRON ACCELERATION BY CASCADING RECONNECTION IN THE SOLAR CORONA. II. RESISTIVE ELECTRIC FIELD EFFECTS

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

    Zhou, X.; Gan, W.; Liu, S.

    We investigate electron acceleration by electric fields induced by cascading reconnections in current sheets trailing coronal mass ejections via a test particle approach in the framework of the guiding-center approximation. Although the resistive electric field is much weaker than the inductive electric field, the electron acceleration is still dominated by the former. Anomalous resistivity η is switched on only in regions where the current carrier’s drift velocity is large enough. As a consequence, electron acceleration is very sensitive to the spatial distribution of the resistive electric fields, and electrons accelerated in different segments of the current sheet have different characteristics.more » Due to the geometry of the 2.5-dimensional electromagnetic fields and strong resistive electric field accelerations, accelerated high-energy electrons can be trapped in the corona, precipitating into the chromosphere or escaping into interplanetary space. The trapped and precipitating electrons can reach a few MeV within 1 s and have a very hard energy distribution. Spatial structure of the acceleration sites may also introduce breaks in the electron energy distribution. Most of the interplanetary electrons reach hundreds of keV with a softer distribution. To compare with observations of solar flares and electrons in solar energetic particle events, we derive hard X-ray spectra produced by the trapped and precipitating electrons, fluxes of the precipitating and interplanetary electrons, and electron spatial distributions.« less

  10. THE MECHANISMS OF ELECTRON ACCELERATION DURING MULTIPLE X LINE MAGNETIC RECONNECTION WITH A GUIDE FIELD

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

    Wang, Huanyu; Lu, Quanming; Huang, Can

    2016-04-20

    The interactions between magnetic islands are considered to play an important role in electron acceleration during magnetic reconnection. In this paper, two-dimensional particle-in-cell simulations are performed to study electron acceleration during multiple X line reconnection with a guide field. Because the electrons remain almost magnetized, we can analyze the contributions of the parallel electric field, Fermi, and betatron mechanisms to electron acceleration during the evolution of magnetic reconnection through comparison with a guide-center theory. The results show that with the magnetic reconnection proceeding, two magnetic islands are formed in the simulation domain. Next, the electrons are accelerated by both themore » parallel electric field in the vicinity of the X lines and the Fermi mechanism due to the contraction of the two magnetic islands. Then, the two magnetic islands begin to merge into one, and, in such a process, the electrons can be accelerated by both the parallel electric field and betatron mechanisms. During the betatron acceleration, the electrons are locally accelerated in the regions where the magnetic field is piled up by the high-speed flow from the X line. At last, when the coalescence of the two islands into one big island finishes, the electrons can be further accelerated by the Fermi mechanism because of the contraction of the big island. With the increase of the guide field, the contributions of the Fermi and betatron mechanisms to electron acceleration become less and less important. When the guide field is sufficiently large, the contributions of the Fermi and betatron mechanisms are almost negligible.« less

  11. Acceleration: It's Elementary

    ERIC Educational Resources Information Center

    Willis, Mariam

    2012-01-01

    Acceleration is one tool for providing high-ability students the opportunity to learn something new every day. Some people talk about acceleration as taking a student out of step. In actuality, what one is doing is putting a student in step with the right curriculum. Whole-grade acceleration, also called grade-skipping, usually happens between…

  12. Accelerating oxygen reduction on Pt monolayer via substrate compression

    NASA Astrophysics Data System (ADS)

    Zhang, Xilin; Chen, Yue; Yang, Zongxian; Lu, Zhansheng

    2017-11-01

    Many methods have been proposed to accelerate the oxygen reduction and save the dosage of Pt. Here, we report a promising way in fulfilling these purposes by applying substrate strain on the supported Pt monolayer. The compressive strain would modify the geometric and electronic structures of tungsten carbide (WC) substrate, changing the interaction nature between substrate and Pt monolayer and resulting in a downward shift of the d-band center of surface Pt atoms. The activity of Pt monolayer on the compressed WC is further evaluated from the kinetics of the dissociation and protonation of O2. The dissociation barrier of O2 is increased and the hydrogenation barrier of O atom is decreased, indicating that the recovery of the catalytically active sites is accelerated and the deactivation by oxygen poison is alleviated. The present study provides an effective way in tuning the activity of Pt-based catalysts by applying the substrate strain.

  13. Cosmic acceleration from matter-curvature coupling

    NASA Astrophysics Data System (ADS)

    Zaregonbadi, Raziyeh; Farhoudi, Mehrdad

    2016-10-01

    We consider f( {R,T} ) modified theory of gravity in which, in general, the gravitational Lagrangian is given by an arbitrary function of the Ricci scalar and the trace of the energy-momentum tensor. We indicate that in this type of the theory, the coupling energy-momentum tensor is not conserved. However, we mainly focus on a particular model that matter is minimally coupled to the geometry in the metric formalism and wherein, its coupling energy-momentum tensor is also conserved. We obtain the corresponding Raychaudhuri dynamical equation that presents the evolution of the kinematic quantities. Then for the chosen model, we derive the behavior of the deceleration parameter, and show that the coupling term can lead to an acceleration phase after the matter dominated phase. On the other hand, the curvature of the universe corresponds with the deviation from parallelism in the geodesic motion. Thus, we also scrutinize the motion of the free test particles on their geodesics, and derive the geodesic deviation equation in this modified theory to study the accelerating universe within the spatially flat FLRW background. Actually, this equation gives the relative accelerations of adjacent particles as a measurable physical quantity, and provides an elegant tool to investigate the timelike and the null structures of spacetime geometries. Then, through the null deviation vector, we find the observer area-distance as a function of the redshift for the chosen model, and compare the results with the corresponding results obtained in the literature.

  14. Linear accelerator: a reproducible, efficacious and cost effective alternative for blood irradiation.

    PubMed

    Shastry, Shamee; Ramya, B; Ninan, Jefy; Srinidhi, G C; Bhat, Sudha S; Fernandes, Donald J

    2013-12-01

    The dedicated devices for blood irradiation are available only at a few centers in developing countries thus the irradiation remains a service with limited availability due to prohibitive cost. To implement a blood irradiation program at our center using linear accelerator. The study is performed detailing the specific operational and quality assurance measures employed in providing a blood component-irradiation service at tertiary care hospital. X-rays generated from linear accelerator were used to irradiate the blood components. To facilitate and standardize the blood component irradiation, a blood irradiator box was designed and fabricated in acrylic. Using Elekta Precise Linear Accelerator, a dose of 25 Gy was delivered at the centre of the irradiation box. Standardization was done using five units of blood obtained from healthy voluntary blood donors. Each unit was divided to two parts. One aliquot was subjected to irradiation. Biochemical and hematological parameters were analyzed on various days of storage. Cost incurred was analyzed. Progressive increase in plasma hemoglobin, potassium and lactate dehydrogenase was noted in the irradiated units but all the parameters were within the acceptable range indicating the suitability of the product for transfusion. The irradiation process was completed in less than 30 min. Validation of the radiation dose done using TLD showed less than ± 3% variation. This study shows that that the blood component irradiation is within the scope of most of the hospitals in developing countries even in the absence of dedicated blood irradiators at affordable cost. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Lead intoxication in dogs: risk assessment of feeding dogs trimmings of lead-shot game.

    PubMed

    Høgåsen, Helga R; Ørnsrud, Robin; Knutsen, Helle K; Bernhoft, Aksel

    2016-07-25

    Expanding lead-based bullets, commonly used for hunting of big game, produce a scattering of lead particles in the carcass around the wound channel. Trimmings around this channel, which are sometimes fed to dogs, may contain lead particles. The aim of this study was to assess potential health effects of feeding dogs such trimmings. Lead ingestion most commonly causes gastrointestinal and neurological clinical signs, although renal, skeletal, haematological, cardiovascular and biochemical effects have also been reported. Experimental data indicate that a daily dose of around 1 mg lead as lead acetate/kg body weight for ten days may be considered as a Lowest Observed Effect Level in dogs. Acute toxicity documentation from the Centers for Disease Control and Prevention indicates 300 mg/kg body weight as the lowest dose of lead acetate causing death in dogs after oral ingestion. Our assessment suggests that dogs fed trimmings of lead-shot game may be affected by the amounts of lead present, and that even deadly exposure could occasionally occur. The intestinal absorption of lead from bullets was assumed to be 10-80 % of that of lead acetate, reflecting both the variability in particle size and uncertainty about the bioavailability of metallic lead in dogs. Despite data gaps, this study indicates that feeding dogs trimmings of lead-shot game may represent a risk of lead intoxication. More research is needed to assess the exact consequences, if lead-based bullets are still to be used. Meanwhile, we recommend that trimmings close to the wound channel should be made inaccessible to dogs, as well as to other domestic or wild animals.

  16. Radio frequency accelerating cavity having slotted irises for damping certain electromagnetic modes

    DOEpatents

    Palmer, Robert B.

    1991-01-01

    An accelerating cavity having one or more iris structures mounted therein for strongly damping unwanted frequencies that are generated in the cavity by bunches of particles in a particle beam that is accelerated through the cavity during its operation. Each of the iris structures is characterized by containing a plurality of radial slots therein that extend from the central aperture through the iris member to the perimeter thereof. The outer end of each of the radial slots includes an enlarged portion that is effective to prevent undesired frequencies from being reflected back into the center aperture of the iris member. Waveguide means connect the outer ends of the radial slots to frequency damping means or to a dump or dumps.

  17. Selected topics in particle accelerators: Proceedings of the CAP meetings. Volume 5

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

    Parsa, Z.

    1995-10-01

    This Report includes copies of transparencies and notes from the presentations made at the Center for Accelerator Physics at Brookhaven National Laboratory Editing and changes to the authors` contributions in this Report were made only to fulfill the publication requirements. This volume includes notes and transparencies on nine presentations: ``The Energy Exchange and Efficiency Consideration in Klystrons``, ``Some Properties of Microwave RF Sources for Future Colliders + Overview of Microwave Generation Activity at the University of Maryland``, ``Field Quality Improvements in Superconducting Magnets for RHIC``, ``Hadronic B-Physics``, ``Spiking Pulses from Free Electron Lasers: Observations and Computational Models``, ``Crystalline Beams inmore » Circular Accelerators``, ``Accumulator Ring for AGS & Recent AGS Performance``, ``RHIC Project Machine Status``, and ``Gamma-Gamma Colliders.``« less

  18. Radio frequency accelerating cavity having slotted irises for damping certain electromagnetic modes

    DOEpatents

    Palmer, R.B.

    1991-05-21

    An accelerating cavity is disclosed having one or more iris structures mounted therein for strongly damping unwanted frequencies that are generated in the cavity by bunches of particles in a particle beam that is accelerated through the cavity during its operation. Each of the iris structures is characterized by containing a plurality of radial slots therein that extend from the central aperture through the iris member to the perimeter thereof. The outer end of each of the radial slots includes an enlarged portion that is effective to prevent undesired frequencies from being reflected back into the center aperture of the iris member. Waveguide means connect the outer ends of the radial slots to frequency damping means or to a dump or dumps. 17 figures.

  19. Terahertz-driven linear electron acceleration

    PubMed Central

    Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; Ravi, Koustuban; Fallahi, Arya; Moriena, Gustavo; Dwayne Miller, R. J.; Kärtner, Franz X.

    2015-01-01

    The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30–50 MeV m−1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/proton accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. These ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams. PMID:26439410

  20. Terahertz-driven linear electron acceleration

    DOE PAGES

    Nanni, Emilio A.; Huang, Wenqian R.; Hong, Kyung-Han; ...

    2015-10-06

    The cost, size and availability of electron accelerators are dominated by the achievable accelerating gradient. Conventional high-brightness radio-frequency accelerating structures operate with 30–50 MeVm -1 gradients. Electron accelerators driven with optical or infrared sources have demonstrated accelerating gradients orders of magnitude above that achievable with conventional radio-frequency structures. However, laser-driven wakefield accelerators require intense femtosecond sources and direct laser-driven accelerators suffer from low bunch charge, sub-micron tolerances and sub-femtosecond timing requirements due to the short wavelength of operation. Here we demonstrate linear acceleration of electrons with keV energy gain using optically generated terahertz pulses. Terahertz-driven accelerating structures enable high-gradient electron/protonmore » accelerators with simple accelerating structures, high repetition rates and significant charge per bunch. As a result, these ultra-compact terahertz accelerators with extremely short electron bunches hold great potential to have a transformative impact for free electron lasers, linear colliders, ultrafast electron diffraction, X-ray science and medical therapy with X-rays and electron beams.« less