A self-consistent view on plasma-neutral interaction near a wall: plasma acceleration by momentum removal and heating by cold walls

NASA Astrophysics Data System (ADS)

van Rooij, Gerard; den Harder, Niek; Minea, Teofil; Shumack, Amy; de Blank, H.; Plasma Physics Team

2014-10-01

In plasma physics, material walls are generally regarded as perfect sinks for charged particles and their energy. A special case arises when the wall efficiently reflects the neutralized plasma particles (with a significant portion of their kinetic energy) and at the same time the upstream plasma is of sufficiently high density to yield strong neutral-ion coupling (i.e. reflected energy and momentum will not escape from the plasma). Under these conditions, plasma-surface interaction will feedback to the upstream plasma and a self-consistent view on the coupling between plasma and neutrals is required for correct prediction of plasma conditions and plasma-surface interaction. Here, an analytical and numerical study of the fluid equations is combined with experiments (in hydrogen and argon) to construct such a self-consistent view. It shows how plasma momentum removal builds up upstream pressure and causes plasma acceleration towards the wall. It also shows how energy reflection causes plasma heating, which recycles part of the reflected power to the wall and induces additional flow acceleration due to local sound speed increase. The findings are relevant as generic textbook example and are at play in the boundary plasma of fusion devices.

Magnetic Shielding of the Channel Walls in a Hall Plasma Accelerator

NASA Technical Reports Server (NTRS)

Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.; Goebel, Dan M.; deGrys, Kristi; Mathers, Alex

2011-01-01

In a qualification life test of a Hall thruster it was found that the erosion of the acceleration channel practically stopped after approx 5,600 h. Numerical simulations using a two-dimensional axisymmetric plasma solver with a magnetic field-aligned mesh reveal that when the channel receded from its early-in-life to its steady-state configuration the following changes occurred near the wall: (1) reduction of the electric field parallel to the wall that prohibited ions from acquiring significant impact kinetic energy before entering the sheath, (2) reduction of the potential fall in the sheath that further diminished the total energy ions gained before striking the material, and (3) reduction of the ion number density that decreased the flux of ions to the wall. All these changes, found to have been induced by the magnetic field, constituted collectively an effective shielding of the walls from any significant ion bombardment. Thus, we term this process in Hall thrusters "magnetic shielding."

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.

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. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, by employing modern computing and solver technologies. The ComPASS vision is to deliver to accelerator scientists a virtual accelerator and virtual prototyping modeling environment, with the necessary multiphysics, multiscale capabilities. The plan for this development includes delivering accelerator modeling applications appropriate for each stage of the ComPASS software evolution. Such applications are already being used to address challenging problems in accelerator design and optimization. The Com

A magnetostrictive acceleration sensor for registration of chest wall displacements

NASA Astrophysics Data System (ADS)

Kaniusas, E.; Mehnen, L.; Krell, C.; Pfützner, H.

2000-06-01

The present study concerns a novel acceleration sensor built up using a bimetallic strip with one freely oscillating end. The strip consists of a magnetostrictive amorphous ribbon glued on a nonmagnetic metal ribbon. The sensor's effectiveness is demonstrated for the case of chest wall displacements as resulting from cardiorespiratory activity. The cheap and easy-to-handle novel sensor offers multiple information on the so-called sleep apnea syndrome.

Accelerator science and technology in Europe 2008-2017

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.

2013-10-01

European Framework Research Projects have recently added a lot of meaning to the building process of the ERA - the European Research Area. Inside this, the accelerator technology plays an essential role. Accelerator technology includes large infrastructure and intelligent, modern instrumentation embracing mechatronics, electronics, photonics and ICT. During the realization of the European research and infrastructure project FP6 CARE 2004-2008 (Coordinated Accelerator Research in Europe), concerning the development of large accelerator infrastructure in Europe, it was decided that a scientific editorial series of peer-reviewed monographs from this research area will be published in close relation with the projects. It was a completely new and quite brave idea to combine a kind of a strictly research publisher with a transient project, lasting only four or five years. Till then nobody did something like that. The idea turned out to be a real success. The publications now known and valued in the accelerator world, as the (CERN-WUT) Editorial Series on Accelerator Science and Technology, is successfully continued in already the third European project EuCARD2 and has logistic guarantees, for the moment, till the 2017, when it will mature to its first decade. During the realization of the European projects EuCARD (European Coordination for Accelerator R&D 2009-2013 and TIARA (Test Infrastructure of Accelerator Research Area in Europe) there were published 18 volumes in this series. The ambitious plans for the nearest years is to publish, hopefully, a few tens of new volumes. 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, published in the monographs of the European Framework Projects (FP) on accelerator technology. The succession of CARE, Eu

Summary of SLAC's SEY Measurement On Flat Accelerator Wall Materials

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

Le Pimpec, F.; /PSI, Villigen /SLAC

The electron cloud effect (ECE) causes beam instabilities in accelerator structures with intense positively charged bunched beams. Reduction of the secondary electron yield (SEY) of the beam pipe inner wall is effective in controlling cloud formation. We summarize SEY results obtained from flat TiN, TiZrV and Al surfaces carried out in a laboratory environment. SEY was measured after thermal conditioning, as well as after low energy, less than 300 eV, particle exposure.

Inelastic collapse and near-wall localization of randomly accelerated particles.

PubMed

Belan, S; Chernykh, A; Lebedev, V; Falkovich, G

2016-05-01

Inelastic collapse of stochastic trajectories of a randomly accelerated particle moving in half-space z>0 has been discovered by McKean [J. Math. Kyoto Univ. 2, 227 (1963)] and then independently rediscovered by Cornell et al. [Phys. Rev. Lett. 81, 1142 (1998)PRLTAO0031-900710.1103/PhysRevLett.81.1142]. The essence of this phenomenon is that the particle arrives at the wall at z=0 with zero velocity after an infinite number of inelastic collisions if the restitution coefficient β of particle velocity is smaller than the critical value β_{c}=exp(-π/sqrt[3]). We demonstrate that inelastic collapse takes place also in a wide class of models with spatially inhomogeneous random forcing and, what is more, that the critical value β_{c} is universal. That class includes an important case of inertial particles in wall-bounded random flows. To establish how inelastic collapse influences the particle distribution, we derive the exact equilibrium probability density function ρ(z,v) for the particle position and velocity. The equilibrium distribution exists only at β<β_{c} and indicates that inelastic collapse does not necessarily imply near-wall localization.

Assessment of fluctuating pressure gradient using acceleration spectra in near wall flows

NASA Astrophysics Data System (ADS)

Cadel, Daniel; Lowe, K. Todd

2015-11-01

Separation of contributions to the fluctuating acceleration from pressure gradient fluctuations and viscous shear fluctuations in the frequency domain is examined in a turbulent boundary layer. Past work leveraging turbulent accelerations for pressure gradient measurements has neglected the viscous shear term from the momentum equation--an invalid assumption in the case of near wall flows. The present study seeks to account for the influence of the viscous shear term and spectrally reject its contribution, which is thought to be concentrated at higher frequencies. Spectra of velocity and acceleration fluctuations in a flat plate, zero pressure gradient turbulent boundary layer at a momentum thickness Reynolds number of 7500 are measured using a spatially resolving three-component laser Doppler velocimeter. This canonical case data is applied for validation of the spectral approach for future application in more complex aerodynamic flows.

Better Particle Accelerators with SRF Technology

ScienceCinema

Padamsee, Hasan; Martinello, Martina; Ross, Marc; Peskin, Michael; Yamamoto, Akira

2018-01-16

The use of superconducting radio frequency (SRF) technology is a driving force in the development of particle accelerators. Scientists from around the globe are working together to develop the newest materials and techniques to improve the quality and efficiency of the SRF cavities that are essential for this technology.

Better Particle Accelerators with SRF Technology

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

Padamsee, Hasan; Martinello, Martina; Ross, Marc

2017-02-20

The use of superconducting radio frequency (SRF) technology is a driving force in the development of particle accelerators. Scientists from around the globe are working together to develop the newest materials and techniques to improve the quality and efficiency of the SRF cavities that are essential for this technology.

Accelerating Technologies: Consequences for the Future Wellbeing of Students

ERIC Educational Resources Information Center

Saltinski, Ronald

2015-01-01

Today's students, K-12 and beyond, will face an ominous future unless educators quickly invest in preparing student perspectives for the accelerating technologies that will have global implications for the wellbeing of all humanity. Accelerating technologies are quietly, almost insidiously, transforming the world with little fanfare and certainly…

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

Accelerator science and technology in Europe: EuCARD 2012

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.

2012-05-01

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 third annual meeting of the EuCARD - European Coordination of Accelerator Research and Development. The conference concerns building of the research infrastructure, including in this advanced photonic and electronic systems for servicing large high energy physics experiments. There are debated a few basic groups of such systems like: measurement - control networks of large geometrical extent, multichannel systems for large amounts of metrological data acquisition, precision photonic networks of reference time, frequency and phase distribution.

1985 Particle Accelerator Conference: Accelerator Engineering and Technology, 11th, Vancouver, Canada, May 13-16, 1985, Proceedings

NASA Astrophysics Data System (ADS)

Strathdee, A.

1985-10-01

The topics discussed are related to high-energy accelerators and colliders, particle sources and electrostatic accelerators, controls, instrumentation and feedback, beam dynamics, low- and intermediate-energy circular accelerators and rings, RF and other acceleration systems, beam injection, extraction and transport, operations and safety, linear accelerators, applications of accelerators, radiation sources, superconducting supercolliders, new acceleration techniques, superconducting components, cryogenics, and vacuum. Accelerator and storage ring control systems are considered along with linear and nonlinear orbit theory, transverse and longitudinal instabilities and cures, beam cooling, injection and extraction orbit theory, high current dynamics, general beam dynamics, and medical and radioisotope applications. Attention is given to superconducting RF structures, magnet technology, superconducting magnets, and physics opportunities with relativistic heavy ion accelerators.

The accelerated site technology deployment program presents the segmented gate system

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

PATTESON,RAYMOND; MAYNOR,DOUG; CALLAN,CONNIE

2000-02-24

The Department of Energy (DOE) is working to accelerate the acceptance and application of innovative technologies that improve the way the nation manages its environmental remediation problems. The DOE Office of Science and Technology established the Accelerated Site Technology Deployment Program (ASTD) to help accelerate the acceptance and implementation of new and innovative soil and ground water remediation technologies. Coordinated by the Department of Energy's Idaho Office, the ASTD Program reduces many of the classic barriers to the deployment of new technologies by involving government, industry, and regulatory agencies in the assessment, implementation, and validation of innovative technologies. The papermore » uses the example of the Segmented Gate System (SGS) to illustrate how the ASTD program works. The SGS was used to cost effectively separate clean and contaminated soil for four different radionuclides: plutonium, uranium, thorium, and cesium. Based on those results, it has been proposed to use the SGS at seven other DOE sites across the country.« less

Self-shielded electron linear accelerators designed for radiation technologies

NASA Astrophysics Data System (ADS)

Belugin, V. M.; Rozanov, N. E.; Pirozhenko, V. M.

2009-09-01

This paper describes self-shielded high-intensity electron linear accelerators designed for radiation technologies. The specific property of the accelerators is that they do not apply an external magnetic field; acceleration and focusing of electron beams are performed by radio-frequency fields in the accelerating structures. The main characteristics of the accelerators are high current and beam power, but also reliable operation and a long service life. To obtain these characteristics, a number of problems have been solved, including a particular optimization of the accelerator components and the application of a variety of specific means. The paper describes features of the electron beam dynamics, accelerating structure, and radio-frequency power supply. Several compact self-shielded accelerators for radiation sterilization and x-ray cargo inspection have been created. The introduced methods made it possible to obtain a high intensity of the electron beam and good performance of the accelerators.

Electron injection and acceleration in the plasma bubble regime driven by an ultraintense laser pulse combined with using dense-plasma wall and block

NASA Astrophysics Data System (ADS)

Zhao, Xue-Yan; Xie, Bai-Song; Wu, Hai-Cheng; Zhang, Shan; Hong, Xue-Ren; Aimidula, Aimierding

2012-03-01

An optimizing and alternative scheme for electron injection and acceleration in the wake bubble driven by an ultraintense laser pulse is presented. In this scheme, the dense-plasma wall with an inner diameter matching the expected bubble size is placed along laser propagation direction. Meanwhile, a dense-plasma block dense-plasma is adhered inward transversely at some certain position of the wall. Particle-in-cell simulations are performed, which demonstrate that the block plays an important role in the first electron injection and acceleration. The result shows that a collimated electron bunch with a total number of about 4.04×108μm-1 can be generated and accelerated stably to 1.61 GeV peak energy with 2.6% energy spread. The block contributes about 50% to the accelerated electron injection bunch by tracing and sorting statistically the source.

Use of adaptive walls in 2D tests

NASA Technical Reports Server (NTRS)

Archambaud, J. P.; Chevallier, J. P.

1984-01-01

A new method for computing the wall effects gives precise answers to some questions arising in adaptive wall concept applications: length of adapted regions, fairings with up and downstream regions, residual misadjustments effects, reference conditions. The acceleration of the iterative process convergence and the development of an efficient technology used in CERT T2 wind tunnels give in a single run the required test conditions. Samples taken from CAST 7 tests demonstrate the efficiency of the whole process to obtain significant results with considerations of tridimensional case extension.

Magnetic Shielding of the Acceleration Channel Walls in a Long-Life Hall Thruster

NASA Technical Reports Server (NTRS)

Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.; Goebel, Dan M.; de Grys, Kristi; Mathers, Alex

2010-01-01

In a Qualification Life Test (QLT) of the BPT-4000 Hall thruster that recently accumulated greater than 10,000 h it was found that the erosion of the acceleration channel practically stopped after approximately 5,600 h. Numerical simulations of this thruster using a 2-D axisymmetric, magnetic field-aligned-mesh (MFAM) plasma solver reveal that the process that led to this significant reduction of the erosion was multifaceted. It is found that when the channel receded from its early-in-life geometry to its steady-state configuration several changes in the near-wall plasma and sheath were induced by the magnetic field that, collectively, constituted an effective shielding of the walls from any significant ion bombardment. Because all such changes in the behavior of the ionized gas near the eroding surfaces were caused by the topology of the magnetic field there, we term this process "magnetic shielding."

Pulsed electron accelerator for radiation technologies in the enviromental applications

NASA Astrophysics Data System (ADS)

Korenev, Sergey

1997-05-01

The project of pulsed electron accelerator for radiation technologies in the environmental applications is considered. An accelerator consists of high voltage generator with vacuum insulation and vacuum diode with plasma cathode on the basis discharge on the surface of dielectric of large dimensions. The main parameters of electron accelerators are following: kinetic energy 0.2 - 2.0 MeV, electron beam current 1 - 30 kA and pulse duration 1- 5 microseconds. The main applications of accelerator for decomposition of wastewaters are considered.

History and Technology Developments of Radio Frequency (RF) Systems for Particle Accelerators

NASA Astrophysics Data System (ADS)

Nassiri, A.; Chase, B.; Craievich, P.; Fabris, A.; Frischholz, H.; Jacob, J.; Jensen, E.; Jensen, M.; Kustom, R.; Pasquinelli, R.

2016-04-01

This article attempts to give a historical account and review of technological developments and innovations in radio frequency (RF) systems for particle accelerators. The evolution from electrostatic field to the use of RF voltage suggested by R. Wideröe made it possible to overcome the shortcomings of electrostatic accelerators, which limited the maximum achievable electric field due to voltage breakdown. After an introduction, we will provide reviews of technological developments of RF systems for particle accelerators.

The R/D of high power proton accelerator technology in China

NASA Astrophysics Data System (ADS)

Xialing, Guan

2002-12-01

In China, a multipurpose verification system as a first phase of our ADS program consists of a low energy accelerator (150 MeV/3 mA proton LINAC) and a swimming pool light water subcritical reactor. In this paper the activities of HPPA technology related to ADS in China, which includes the intense proton ECR source, the RFQ accelerator and some other technology of HPPA, are described.

Terascale Computing in Accelerator Science and Technology

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

Ko, Kwok

2002-08-21

We have entered the age of ''terascale'' scientific computing. Processors and system architecture both continue to evolve; hundred-teraFLOP computers are expected in the next few years, and petaFLOP computers toward the end of this decade are conceivable. This ever-increasing power to solve previously intractable numerical problems benefits almost every field of science and engineering and is revolutionizing some of them, notably including accelerator physics and technology. At existing accelerators, it will help us optimize performance, expand operational parameter envelopes, and increase reliability. Design decisions for next-generation machines will be informed by unprecedented comprehensive and accurate modeling, as well as computer-aidedmore » engineering; all this will increase the likelihood that even their most advanced subsystems can be commissioned on time, within budget, and up to specifications. Advanced computing is also vital to developing new means of acceleration and exploring the behavior of beams under extreme conditions. With continued progress it will someday become reasonable to speak of a complete numerical model of all phenomena important to a particular accelerator.« less

Tunable inertia of chiral magnetic domain walls

PubMed Central

Torrejon, Jacob; Martinez, Eduardo; Hayashi, Masamitsu

2016-01-01

The time it takes to accelerate an object from zero to a given velocity depends on the applied force and the environment. If the force ceases, it takes exactly the same time to completely decelerate. A magnetic domain wall is a topological object that has been observed to follow this behaviour. Here we show that acceleration and deceleration times of chiral Neel walls driven by current are different in a system with low damping and moderate Dzyaloshinskii–Moriya exchange constant. The time needed to accelerate a domain wall with current via the spin Hall torque is much faster than the time it needs to decelerate once the current is turned off. The deceleration time is defined by the Dzyaloshinskii–Moriya exchange constant whereas the acceleration time depends on the spin Hall torque, enabling tunable inertia of chiral domain walls. Such unique feature of chiral domain walls can be utilized to move and position domain walls with lower current, key to the development of storage class memory devices. PMID:27882932

Accelerated whole brain intracranial vessel wall imaging using black blood fast spin echo with compressed sensing (CS-SPACE).

PubMed

Zhu, Chengcheng; Tian, Bing; Chen, Luguang; Eisenmenger, Laura; Raithel, Esther; Forman, Christoph; Ahn, Sinyeob; Laub, Gerhard; Liu, Qi; Lu, Jianping; Liu, Jing; Hess, Christopher; Saloner, David

2018-06-01

Develop and optimize an accelerated, high-resolution (0.5 mm isotropic) 3D black blood MRI technique to reduce scan time for whole-brain intracranial vessel wall imaging. A 3D accelerated T 1 -weighted fast-spin-echo prototype sequence using compressed sensing (CS-SPACE) was developed at 3T. Both the acquisition [echo train length (ETL), under-sampling factor] and reconstruction parameters (regularization parameter, number of iterations) were first optimized in 5 healthy volunteers. Ten patients with a variety of intracranial vascular disease presentations (aneurysm, atherosclerosis, dissection, vasculitis) were imaged with SPACE and optimized CS-SPACE, pre and post Gd contrast. Lumen/wall area, wall-to-lumen contrast ratio (CR), enhancement ratio (ER), sharpness, and qualitative scores (1-4) by two radiologists were recorded. The optimized CS-SPACE protocol has ETL 60, 20% k-space under-sampling, 0.002 regularization factor with 20 iterations. In patient studies, CS-SPACE and conventional SPACE had comparable image scores both pre- (3.35 ± 0.85 vs. 3.54 ± 0.65, p = 0.13) and post-contrast (3.72 ± 0.58 vs. 3.53 ± 0.57, p = 0.15), but the CS-SPACE acquisition was 37% faster (6:48 vs. 10:50). CS-SPACE agreed with SPACE for lumen/wall area, ER measurements and sharpness, but marginally reduced the CR. In the evaluation of intracranial vascular disease, CS-SPACE provides a substantial reduction in scan time compared to conventional T 1 -weighted SPACE while maintaining good image quality.

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.

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.

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.

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

High brightness electron accelerator

DOEpatents

Sheffield, Richard L.; Carlsten, Bruce E.; Young, Lloyd M.

1994-01-01

A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

Vessel wall characterization using quantitative MRI: what's in a number?

PubMed

Coolen, Bram F; Calcagno, Claudia; van Ooij, Pim; Fayad, Zahi A; Strijkers, Gustav J; Nederveen, Aart J

2018-02-01

The past decade has witnessed the rapid development of new MRI technology for vessel wall imaging. Today, with advances in MRI hardware and pulse sequences, quantitative MRI of the vessel wall represents a real alternative to conventional qualitative imaging, which is hindered by significant intra- and inter-observer variability. Quantitative MRI can measure several important morphological and functional characteristics of the vessel wall. This review provides a detailed introduction to novel quantitative MRI methods for measuring vessel wall dimensions, plaque composition and permeability, endothelial shear stress and wall stiffness. Together, these methods show the versatility of non-invasive quantitative MRI for probing vascular disease at several stages. These quantitative MRI biomarkers can play an important role in the context of both treatment response monitoring and risk prediction. Given the rapid developments in scan acceleration techniques and novel image reconstruction, we foresee the possibility of integrating the acquisition of multiple quantitative vessel wall parameters within a single scan session.

Stimulating Innovation and Accelerating the Development of Complex and Slowly Maturing Technologies Through Advanced Technology Prize Competitions

DTIC Science & Technology

2007-06-15

technology prize competitions have been used since the 18th century to spur innovation and advance the development of complex and slowly maturing disruptive ... technologies The Defense Advanced Research Projects Agency (DARPA) has used advanced technology competitions in 2004 and 2005 to rapidly accelerate the

Field Emission in Superconducting Accelerators: Instrumented Measurements for Its Understanding and Mitigation

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

Geng, Rongli; Freyberger, Arne P.; Legg, Robert A.

Several new accelerator projects are adopting superconducting accelerator technology. When accelerating cavities maintain high RF gradients, field emission, the emission of electrons from cavity walls, can occur and may impact operational cavity gradient, radiological environment via activated components, and reliability. In this talk, we will discuss instrumented measurements of field emission from the two 1.1 GeV superconducting continuous wave (CW) linacs in CEBAF. The goal is to improve the understanding of field emission sources originating from cryomodule production, installation and operation. Such basic knowledge is needed in guiding field emission control, mitigation, and reduction toward high gradient and reliable operationmore » of superconducting accelerators.« less

Development of advanced technological systems for accelerator transmutation

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

Batskikh, G.I.; Bondarev, B.I.; Durkin, A.P.

1995-10-01

A development concept of the accelerator nuclear energy reactors is considered for energy generation and nuclear power plant waste conversion into short-lived nuclides along with the requirements imposed on the technological systems necessary for implementation of such projects. The state of art in the field is discussed.

Factors Associated With Chest Wall Toxicity After Accelerated Partial Breast Irradiation Using High-Dose-Rate Brachytherapy

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

Brown, Sheree, E-mail: shereedst32@hotmail.com; Vicini, Frank; Vanapalli, Jyotsna R.

2012-07-01

Purpose: The purpose of this analysis was to evaluate dose-volume relationships associated with a higher probability for developing chest wall toxicity (pain) after accelerated partial breast irradiation (APBI) by using both single-lumen and multilumen brachytherapy. Methods and Materials: Rib dose data were available for 89 patients treated with APBI and were correlated with the development of chest wall/rib pain at any point after treatment. Ribs were contoured on computed tomography planning scans, and rib dose-volume histograms (DVH) along with histograms for other structures were constructed. Rib DVH data for all patients were sampled at all volumes {>=}0.008 cubic centimeter (cc)more » (for maximum dose related to pain) and at volumes of 0.5, 1, 2, and 3 cc for analysis. Rib pain was evaluated at each follow-up visit. Patient responses were marked as yes or no. No attempt was made to grade responses. Eighty-nine responses were available for this analysis. Results: Nineteen patients (21.3%) complained of transient chest wall/rib pain at any point in follow-up. Analysis showed a direct correlation between total dose received and volume of rib irradiated with the probability of developing rib/chest wall pain at any point after follow-up. The median maximum dose at volumes {>=}0.008 cc of rib in patients who experienced chest wall pain was 132% of the prescribed dose versus 95% of the prescribed dose in those patients who did not experience pain (p = 0.0035). Conclusions: Although the incidence of chest wall/rib pain is quite low with APBI brachytherapy, attempts should be made to keep the volume of rib irradiated at a minimum and the maximum dose received by the chest wall as low as reasonably achievable.« less

Standard Modular Hydropower Technology Acceleration Workshop: Summary Report

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

Smith, Brennan T.; DeNeale, Scott T.; Witt, Adam M.

In support of the Department of Energy (DOE) funded Standard Modular Hydropower (SMH) Technology Acceleration project, Oak Ridge National Laboratory (ORNL) staff convened with five small hydropower technology entrepreneurs on June 14 and 15, 2017 to discuss gaps, challenges, and opportunities for small modular hydropower development. The workshop was designed to walk through SMH concepts, discuss the SMH research vision, assess how each participant’s technology aligns with SMH concepts and research, and identify future pathways for mutually beneficial collaboration that leverages ORNL expertise and entrepreneurial industry experience. The goal coming out of the workshop is to advance standardized, scalable, modularmore » hydropower technologies and development approaches with sustained and open dialogue among diverse stakeholder groups.« less

Magnesium diboride coated bulk niobium: a new approach to higher acceleration gradient

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

Tan, Teng; Wolak, M. A.; Xi, X. X.

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 significantmore » 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. In conclusion, this finding creates a new route towards achieving higher acceleration gradient in SRF cavity accelerator beyond the theoretical limit of bulk Nb.« less

Double Wall Framing Technique An Example of High Performance, Sustainable Building Envelope Technology

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

Kosny, Dr. Jan; Asiz, Andi; Shrestha, Som S

2015-01-01

Double wall technologies utilizing wood framing have been well-known and used in North American buildings for decades. Most of double wall designs use only natural materials such as wood products, gypsum, and cellulose fiber insulation, being one of few building envelope technologies achieving high thermal performance without use of plastic foams or fiberglass. Today, after several material and structural design modifications, these technologies are considered as highly thermally efficient, sustainable option for new constructions and sometimes, for retrofit projects. Following earlier analysis performed for U.S. Department of Energy by Fraunhofer CSE, this paper discusses different ways to build double wallsmore » and to optimize their thermal performance to minimize the space conditioning energy consumption. Description of structural configuration alternatives and thermal performance analysis are presented as well. Laboratory tests to evaluate thermal properties of used insulation and whole wall system thermal performance are also discussed in this paper. Finally, the thermal loads generated in field conditions by double walls are discussed utilizing results from a joined project performed by Zero Energy Building Research Alliance and Oak Ridge National Laboratory (ORNL), which made possible evaluation of the market viability of low-energy homes built in the Tennessee Valley. Experimental data recorded in two of the test houses built during this field study is presented in this work.« less

Results of Measurements of Accelerations of Technological Devices onboard the FotonSpacecraft

NASA Astrophysics Data System (ADS)

Barmin, I. V.; Volkov, M. V.; Egorov, A. V.; Reut, E. F.; Senchenkov, A. S.

2001-07-01

This paper generalizes the results of measuring the residual accelerations arising when investigations in space materials science are carried out onboard the unmanned Fotonspacecraft. The levels of vibroaccelerations are analyzed in the frequency band of 1 500 Hz for the technological devices UZ01, UZ04, and POLIZON, developed by the Federal Unitary State Enterprise “Barmin Design Bureau of General Machine Building” (V.P. Barmin KBOM). The levels of accelerations are estimated in the frequency band of 0 1 Hz in the zone of technological operations of these facilities. The basic sources of vibroaccelerations acting upon the frames of devices are determined in the capsule zone, where technological processes of producing new materials take place. In the frequency band of 1 500 Hz the vibroaccelerations are shown to be generated by the operation of Fotonspacecraft units and a drive of capsule translation during the technological process. On the capsule frame they reach the values of (1 3) × 10 3 g. The level of linear accelerations in the infralow-frequency band is determined by rotational motions of the Fotonspacecraft. It depends on the device location with respect to the spacecraft center of mass and does not exceed (1 7) × 10 6 gin the steady-state regime in the zone of technological activity.

Southern California Regional Technology Acceleration Program

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

Ochoa, Rosibel; Rasochova, Lada

2014-09-30

UC San Diego and San Diego State University are partnering to address these deficiencies in the renewable energy space in the greater San Diego region, accelerating the movement of clean energy innovation from the university laboratory into the marketplace, building on the proven model of the William J. von Liebig Center’s (vLC’s) Proof of Concept (POC) program and virtualizing the effort to enable a more inclusive environment for energy innovation and expansion of the number of clean energy start-ups and/or technology licenses in greater California.

Basic and applied studies of the ram accelerator as a hypervelocity projectile launcher

NASA Astrophysics Data System (ADS)

Bruckner, Adam P.; Knowlen, Carl

1993-12-01

The potential of using ram accelerator technology for an impulsive launcher of autonomously guided interceptors, such as the LEAP, has been studied during this contract period. In addition, fundamental investigations on some of the engineering issues which must be addressed for enabling ram accelerator propulsive modes to operate at 4 km/sec have been undertaken. An experimental investigation of the gas dynamic limits of ram accelerator operation has demonstrated the existence of two distinct limiting mechanisms that must be accounted for when designing projectiles for these launchers. Other experiments were conducted to make detailed pressure measurements of the flow fields at the tube walls to study the effects of projectile canting. Results from this LEAP launcher study and the experimental investigations indicate that the ram accelerator technology is well suited for applications as a transportable launcher capable of meeting the needs of theater ballistic missile defense missions.

Accelerating innovation in information and communication technology for health.

PubMed

Crean, Kevin W

2010-02-01

Around the world, inventors are creating novel information and communication technology applications and systems that can improve health for people in disparate settings. However, it is very difficult to find investment funding needed to create business models to expand and develop the prototype technologies. A comprehensive, long-term investment strategy for e-health and m-health is needed. The field of social entrepreneurship offers an integrated approach to develop needed investment models, so that innovations can reach more patients, more effectively. Specialized financing techniques and sustained support from investors can spur the expansion of mature technologies to larger markets, accelerating global health impacts.

Development of the Accelerator Mass Spectrometry technology at the Comenius University in Bratislava

NASA Astrophysics Data System (ADS)

Povinec, Pavel P.; Masarik, Jozef; Ješkovský, Miroslav; Kaizer, Jakub; Šivo, Alexander; Breier, Robert; Pánik, Ján; Staníček, Jaroslav; Richtáriková, Marta; Zahoran, Miroslav; Zeman, Jakub

2015-10-01

An Accelerator Mass Spectrometry (AMS) laboratory has been established at the Centre for Nuclear and Accelerator Technologies (CENTA) at the Comenius University in Bratislava comprising of a MC-SNICS ion source, 3 MV Pelletron tandem accelerator, and an analyzer of accelerated ions. The preparation of targets for 14C and 129I AMS measurements is described in detail. The development of AMS techniques for potassium, uranium and thorium analysis in radiopure materials required for ultra-low background underground experiments is briefly mentioned.

Technology Solutions Case Study: Stud Walls with Continuous Exterior Insulation for Factory Built Housing

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

None

The Advanced Envelope Research effort will provide factory homebuilders with high performance, cost-effective alternative envelope designs. In the near term, these technologies will play a central role in meeting stringent energy code requirements. For manufactured homes, the thermal requirements, last updated by statute in 1994, will move up to the more rigorous IECC 2012 levels in 2013, the requirements of which are consistent with site built and modular housing. This places added urgency on identifying envelope technologies that the industry can implement in the short timeframe. The primary goal of this research is to develop wall designs that meet themore » thermal requirements based on 2012 IECC standards. Given the affordable nature of manufactured homes, impact on first cost is a major consideration in developing the new envelope technologies. This work is part of a four-phase, multi-year effort. Phase 1 identified seven envelope technologies and provided a preliminary assessment of three selected methods for building high performance wall systems. Phase 2 focused on the development of viable product designs, manufacturing strategies, addressing code and structural issues, and cost analysis of the three selected options. An industry advisory committee helped critique and select the most viable solution to move further in the research — stud walls with continuous exterior insulation. Phase 3, the subject of the current report, focused on the design development of the selected wall concept and explored variations on the use of exterior foam insulation. The scope also included material selection, manufacturing and cost analysis, and prototyping and testing.« less

Lagrangian acceleration statistics in a turbulent channel flow

NASA Astrophysics Data System (ADS)

Stelzenmuller, Nickolas; Polanco, Juan Ignacio; Vignal, Laure; Vinkovic, Ivana; Mordant, Nicolas

2017-05-01

Lagrangian acceleration statistics in a fully developed turbulent channel flow at Reτ=1440 are investigated, based on tracer particle tracking in experiments and direct numerical simulations. The evolution with wall distance of the Lagrangian velocity and acceleration time scales is analyzed. Dependency between acceleration components in the near-wall region is described using cross-correlations and joint probability density functions. The strong streamwise coherent vortices typical of wall-bounded turbulent flows are shown to have a significant impact on the dynamics. This results in a strong anisotropy at small scales in the near-wall region that remains present in most of the channel. Such statistical properties may be used as constraints in building advanced Lagrangian stochastic models to predict the dispersion and mixing of chemical components for combustion or environmental studies.

Accelerated technology transfer: the UK quantum initiative

NASA Astrophysics Data System (ADS)

Bennett, Simon D.

2016-10-01

A new generation of quantum technology based systems, exploiting effects such as superposition and entanglement, will enable widespread, highly disruptive applications which are expected to be of great economic significance. However, the technology is only just emerging from the physics laboratory and generally remains at low TRLs. The question is: where, and when, will this impact be first manifest? The UK, with substantial Government backing, has embarked on an ambitious national program to accelerate the process of technology transfer with the objective of seizing a significant and sustainable share of the future economic benefit for the UK. Many challenges and uncertainties remain but the combined and co-ordinated efforts of Government, Industry and Academia are making great progress. The level of collaboration is unusually high and the goal of embedding a "QT Ecosystem" in the UK looks to be attainable. This paper describes the UK national programme, its key players, and their respective roles. It will illustrate some of the likely first commercial applications and provide a status update. Some of the challenges that might prevent realisation of the goal will be highlighted.

A proton medical accelerator by the SBIR route — an example of technology transfer

NASA Astrophysics Data System (ADS)

Martin, R. L.

1989-04-01

Medical facilities for radiation treatment of cancer with protons have been established in many laboratories throughout the world. Essentially all of these have been designed as physics facilities, however, because of the requirement for protons up to 250 MeV. Most of the experience in this branch of accelerator technology lies in the national laboratories and a few large universities. A major issue is the transfer of this technology to the commercial sector to provide hospitals with simple, reliable and relatively inexpensive accelerators for this application. The author has chosen the SBIR route to accomplish this goal. ACCTEK Associates has received grants from the National Cancer Institute for development of the medical accelerator and beam delivery systems. Considerable encouragement and help has been received from Argonne National Laboratory and the Department of Energy. The experiences to date and the pros and cons on this approach to commercializing medical accelerators are described.

Arc-driven rail accelerator research

NASA Technical Reports Server (NTRS)

Ray, Pradosh K.

1987-01-01

Arc-driven rail accelerator research is analyzed by considering wall ablation and viscous drag in the plasma. Plasma characteristics are evaluated through a simple fluid-mechanical analysis considering only wall ablation. By equating the energy dissipated in the plasma with the radiation heat loss, the average properties of the plasma are determined as a function of time and rate of ablation. Locations of two simultaneously accelerating arcs were determined by optical and magnetic probes and fron streak camera photographs. All three measurements provide consistent results.

A beamline systems model for Accelerator-Driven Transmutation Technology (ADTT) facilities

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

Todd, A.M.M.; Paulson, C.C.; Peacock, M.A.

1995-10-01

A beamline systems code, that is being developed for Accelerator-Driven Transmutation Technology (ADTT) facility trade studies, is described. The overall program is a joint Grumman, G.H. Gillespie Associates (GHGA) and Los Alamos National Laboratory effort. The GHGA Accelerator Systems Model (ASM) has been adopted as the framework on which this effort is based. Relevant accelerator and beam transport models from earlier Grumman systems codes are being adapted to this framework. Preliminary physics and engineering models for each ADTT beamline component have been constructed. Examples noted include a Bridge Coupled Drift Tube Linac (BCDTL) and the accelerator thermal system. A decisionmore » has been made to confine the ASM framework principally to beamline modeling, while detailed target/blanket, balance-of-plant and facility costing analysis will be performed externally. An interfacing external balance-of-plant and facility costing model, which will permit the performance of iterative facility trade studies, is under separate development. An ABC (Accelerator Based Conversion) example is used to highlight the present models and capabilities.« less

A beamline systems model for Accelerator-Driven Transmutation Technology (ADTT) facilities

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

Todd, Alan M. M.; Paulson, C. C.; Peacock, M. A.

1995-09-15

A beamline systems code, that is being developed for Accelerator-Driven Transmutation Technology (ADTT) facility trade studies, is described. The overall program is a joint Grumman, G. H. Gillespie Associates (GHGA) and Los Alamos National Laboratory effort. The GHGA Accelerator Systems Model (ASM) has been adopted as the framework on which this effort is based. Relevant accelerator and beam transport models from earlier Grumman systems codes are being adapted to this framework. Preliminary physics and engineering models for each ADTT beamline component have been constructed. Examples noted include a Bridge Coupled Drift Tube Linac (BCDTL) and the accelerator thermal system. Amore » decision has been made to confine the ASM framework principally to beamline modeling, while detailed target/blanket, balance-of-plant and facility costing analysis will be performed externally. An interfacing external balance-of-plant and facility costing model, which will permit the performance of iterative facility trade studies, is under separate development. An ABC (Accelerator Based Conversion) example is used to highlight the present models and capabilities.« less

Secondary electron emission from plasma processed accelerating cavity grade niobium

NASA Astrophysics Data System (ADS)

Basovic, Milos

Advances in the particle accelerator technology have enabled numerous fundamental discoveries in 20th century physics. Extensive interdisciplinary research has always supported further development of accelerator technology in efforts of reaching each new energy frontier. Accelerating cavities, which are used to transfer energy to accelerated charged particles, have been one of the main focuses of research and development in the particle accelerator field. Over the last fifty years, in the race to break energy barriers, there has been constant improvement of the maximum stable accelerating field achieved in accelerating cavities. Every increase in the maximum attainable accelerating fields allowed for higher energy upgrades of existing accelerators and more compact designs of new accelerators. Each new and improved technology was faced with ever emerging limiting factors. With the standard high accelerating gradients of more than 25 MV/m, free electrons inside the cavities get accelerated by the field, gaining enough energy to produce more electrons in their interactions with the walls of the cavity. The electron production is exponential and the electron energy transfer to the walls of a cavity can trigger detrimental processes, limiting the performance of the cavity. The root cause of the free electron number gain is a phenomenon called Secondary Electron Emission (SEE). Even though the phenomenon has been known and studied over a century, there are still no effective means of controlling it. The ratio between the electrons emitted from the surface and the impacting electrons is defined as the Secondary Electron Yield (SEY). A SEY ratio larger than 1 designates an increase in the total number of electrons. In the design of accelerator cavities, the goal is to reduce the SEY to be as low as possible using any form of surface manipulation. In this dissertation, an experimental setup was developed and used to study the SEY of various sample surfaces that were treated

Secondary Electron Emission from Plasma Processed Accelerating Cavity Grade Niobium

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

Basovic, Milos

Advances in the particle accelerator technology have enabled numerous fundamental discoveries in 20th century physics. Extensive interdisciplinary research has always supported further development of accelerator technology in efforts of reaching each new energy frontier. Accelerating cavities, which are used to transfer energy to accelerated charged particles, have been one of the main focuses of research and development in the particle accelerator field. Over the last fifty years, in the race to break energy barriers, there has been constant improvement of the maximum stable accelerating field achieved in accelerating cavities. Every increase in the maximum attainable accelerating fields allowed for highermore » energy upgrades of existing accelerators and more compact designs of new accelerators. Each new and improved technology was faced with ever emerging limiting factors. With the standard high accelerating gradients of more than 25 MV/m, free electrons inside the cavities get accelerated by the field, gaining enough energy to produce more electrons in their interactions with the walls of the cavity. The electron production is exponential and the electron energy transfer to the walls of a cavity can trigger detrimental processes, limiting the performance of the cavity. The root cause of the free electron number gain is a phenomenon called Secondary Electron Emission (SEE). Even though the phenomenon has been known and studied over a century, there are still no effective means of controlling it. The ratio between the electrons emitted from the surface and the impacting electrons is defined as the Secondary Electron Yield (SEY). A SEY ratio larger than 1 designates an increase in the total number of electrons. In the design of accelerator cavities, the goal is to reduce the SEY to be as low as possible using any form of surface manipulation. In this dissertation, an experimental setup was developed and used to study the SEY of various sample surfaces that were

EDITORIAL: Metrological Aspects of Accelerator Technology and High Energy Physics Experiments

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.; Pozniak, Krzysztof T.

2007-08-01

The subject of this special feature in Measurement Science and Technology concerns measurement methods, devices and subsystems, both hardware and software aspects, applied in large experiments of high energy physics (HEP) and superconducting RF accelerator technology (SRF). These experiments concern mainly the physics of elementary particles or the building of new machines and detectors. The papers present practical examples of applied solutions in large, contemporary, international research projects such as HERA, LHC, FLASH, XFEL, ILC and others. These machines are unique in their global scale and consist of extremely dedicated apparatus. The apparatus is characterized by very large dimensions, a considerable use of resources and a high level of overall technical complexity. They possess a large number of measurement channels (ranging from thousands to over 100 million), are characterized by fast of processing of measured data and high measurement accuracies, and work in quite adverse environments. The measurement channels cooperate with a large number of different sensors of momenta, energies, trajectories of elementary particles, electron, proton and photon beam profiles, accelerating fields in resonant cavities, and many others. The provision of high quality measurement systems requires the designers to use only the most up-to-date technical solutions, measurement technologies, components and devices. Research work in these demanding fields is a natural birthplace of new measurement methods, new data processing and acquisition algorithms, complex, networked measurement system diagnostics and monitoring. These developments are taking place in both hardware and software layers. The chief intention of this special feature is that the papers represent equally some of the most current metrology research problems in HEP and SRF. The accepted papers have been divided into four topical groups: superconducting cavities (4 papers), low level RF systems (8 papers

Enabling More than Moore: Accelerated Reliability Testing and Risk Analysis for Advanced Electronics Packaging

NASA Technical Reports Server (NTRS)

Ghaffarian, Reza; Evans, John W.

2014-01-01

For five decades, the semiconductor industry has distinguished itself by the rapid pace of improvement in miniaturization of electronics products-Moore's Law. Now, scaling hits a brick wall, a paradigm shift. The industry roadmaps recognized the scaling limitation and project that packaging technologies will meet further miniaturization needs or ak.a "More than Moore". This paper presents packaging technology trends and accelerated reliability testing methods currently being practiced. Then, it presents industry status on key advanced electronic packages, factors affecting accelerated solder joint reliability of area array packages, and IPC/JEDEC/Mil specifications for characterizations of assemblies under accelerated thermal and mechanical loading. Finally, it presents an examples demonstrating how Accelerated Testing and Analysis have been effectively employed in the development of complex spacecraft thereby reducing risk. Quantitative assessments necessarily involve the mathematics of probability and statistics. In addition, accelerated tests need to be designed which consider the desired risk posture and schedule for particular project. Such assessments relieve risks without imposing additional costs. and constraints that are not value added for a particular mission. Furthermore, in the course of development of complex systems, variances and defects will inevitably present themselves and require a decision concerning their disposition, necessitating quantitative assessments. In summary, this paper presents a comprehensive view point, from technology to systems, including the benefits and impact of accelerated testing in offsetting risk.

ANNULUS CLOSURE TECHNOLOGY DEVELOPMENT INSPECTION/SALT DEPOSIT CLEANING MAGNETIC WALL CRAWLER

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

Minichan, R; Russell Eibling, R; James Elder, J

2008-06-01

The Liquid Waste Technology Development organization is investigating technologies to support closure of radioactive waste tanks at the Savannah River Site (SRS). Tank closure includes removal of the wastes that have propagated to the tank annulus. Although amounts and types of residual waste materials in the annuli of SRS tanks vary, simple salt deposits are predominant on tanks with known leak sites. This task focused on developing and demonstrating a technology to inspect and spot clean salt deposits from the outer primary tank wall located in the annulus of an SRS Type I tank. The Robotics, Remote and Specialty Equipmentmore » (RRSE) and Materials Science and Technology (MS&T) Sections of the Savannah River National Laboratory (SRNL) collaborated to modify and equip a Force Institute magnetic wall crawler with the tools necessary to demonstrate the inspection and spot cleaning in a mock-up of a Type I tank annulus. A remote control camera arm and cleaning head were developed, fabricated and mounted on the crawler. The crawler was then tested and demonstrated on a salt simulant also developed in this task. The demonstration showed that the camera is capable of being deployed in all specified locations and provided the views needed for the planned inspection. It also showed that the salt simulant readily dissolves with water. The crawler features two different techniques for delivering water to dissolve the salt deposits. Both water spay nozzles were able to dissolve the simulated salt, one is more controllable and the other delivers a larger water volume. The cleaning head also includes a rotary brush to mechanically remove the simulated salt nodules in the event insoluble material is encountered. The rotary brush proved to be effective in removing the salt nodules, although some fine tuning may be required to achieve the best results. This report describes the design process for developing technology to add features to a commercial wall crawler and the

Taking Down a Giant: 699 Tons of SLAC’s Accelerator Removed for Upgrade

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

None

2017-01-31

For the first time in more than 50 years, a door opened at the western end of the historic linear accelerator at the Department of Energy’s SLAC National Accelerator Laboratory casts light on four empty walls stretching as far as the eye can see. This end of the linac – a full kilometer of it – has been stripped of all its equipment both above and below ground. Over the next two years it will be re-equipped with new technology to power another wonder of modern science: an X-ray laser that will fire a million pulses per second.

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.

Breakthrough: Fermilab Accelerator Technology

ScienceCinema

None

2018-02-07

There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

Breakthrough: Fermilab Accelerator Technology

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

None

2012-04-23

There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

Experimental Characterization of a Plasma Deflagration Accelerator for Simulating Fusion Wall Response to Disruption Events

NASA Astrophysics Data System (ADS)

Underwood, Thomas; Loebner, Keith; Cappelli, Mark

2016-10-01

In this work, the suitability of a pulsed deflagration accelerator to simulate the interaction of edge-localized modes with plasma first wall materials is investigated. Experimental measurements derived from a suite of diagnostics are presented that focus on the both the properties of the plasma jet and the manner in which such jets couple with material interfaces. Detailed measurements of the thermodynamic plasma state variables within the jet are presented using a quadruple Langmuir probe operating in current-saturation mode. This data in conjunction with spectroscopic measurements of H α Stark broadening via a fast-framing, intensified CCD camera provide spatial and temporal measurements of how the plasma density and temperature scale as a function of input energy. Using these measurements, estimates for the energy flux associated with the deflagration accelerator are found to be completely tunable over a range spanning 150 MW m-2 - 30 GW m-2. The plasma-material interface is investigated using tungsten tokens exposed to the plasma plume under variable conditions. Visualizations of resulting shock structures are achieved through Schlieren cinematography and energy transfer dynamics are discussed by presenting temperature measurements of exposed materials. This work is supported by the U.S. Department of Energy Stewardship Science Academic Program in addition to the National Defense Science Engineering Graduate Fellowship.

Extraordinary Tools for Extraordinary Science: The Impact ofSciDAC on Accelerator Science&Technology

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

Ryne, Robert D.

2006-08-10

Particle accelerators are among the most complex and versatile instruments of scientific exploration. They have enabled remarkable scientific discoveries and important technological advances that span all programs within the DOE Office of Science (DOE/SC). The importance of accelerators to the DOE/SC mission is evident from an examination of the DOE document, ''Facilities for the Future of Science: A Twenty-Year Outlook''. Of the 28 facilities listed, 13 involve accelerators. Thanks to SciDAC, a powerful suite of parallel simulation tools has been developed that represent a paradigm shift in computational accelerator science. Simulations that used to take weeks or more now takemore » hours, and simulations that were once thought impossible are now performed routinely. These codes have been applied to many important projects of DOE/SC including existing facilities (the Tevatron complex, the Relativistic Heavy Ion Collider), facilities under construction (the Large Hadron Collider, the Spallation Neutron Source, the Linac Coherent Light Source), and to future facilities (the International Linear Collider, the Rare Isotope Accelerator). The new codes have also been used to explore innovative approaches to charged particle acceleration. These approaches, based on the extremely intense fields that can be present in lasers and plasmas, may one day provide a path to the outermost reaches of the energy frontier. Furthermore, they could lead to compact, high-gradient accelerators that would have huge consequences for US science and technology, industry, and medicine. In this talk I will describe the new accelerator modeling capabilities developed under SciDAC, the essential role of multi-disciplinary collaboration with applied mathematicians, computer scientists, and other IT experts in developing these capabilities, and provide examples of how the codes have been used to support DOE/SC accelerator projects.« less

Optically pulsed electron accelerator

DOEpatents

Fraser, John S.; Sheffield, Richard L.

1987-01-01

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Optically pulsed electron accelerator

DOEpatents

Fraser, J.S.; Sheffield, R.L.

1985-05-20

An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

Computational screening of organic polymer dielectrics for novel accelerator technologies

DOE PAGES

Pilania, Ghanshyam; Weis, Eric; Walker, Ethan M.; ...

2018-06-18

The use of infrared lasers to power accelerating dielectric structures is a developing area of research. Within this technology, the choice of the dielectric material forming the accelerating structures, such as the photonic band gap (PBG) structures, is dictated by a range of interrelated factors including their dielectric and optical properties, amenability to photo-polymerization, thermochemical stability and other target performance metrics of the particle accelerator. In this direction, electronic structure theory aided computational screening and design of dielectric materials can play a key role in identifying potential candidate materials with the targeted functionalities to guide experimental synthetic efforts. In anmore » attempt to systematically understand the role of chemistry in controlling the electronic structure and dielectric properties of organic polymeric materials, here we employ empirical screening and density functional theory (DFT) computations, as a part of our multi-step hierarchal screening strategy. Our DFT based analysis focused on the bandgap, dielectric permittivity, and frequency-dependent dielectric losses due to lattice absorption as key properties to down-select promising polymer motifs. In addition to the specific application of dielectric laser acceleration, the general methodology presented here is deemed to be valuable in the design of new insulators with an attractive combination of dielectric properties.« less

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

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

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.

Ultra-high vacuum photoelectron linear accelerator

DOEpatents

Yu, David U.L.; Luo, Yan

2013-07-16

An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.

Wall Street's assessment of plastic surgery--related technology: a clinical and financial analysis.

PubMed

Krieger, L M; Shaw, W W

2000-02-01

Many plastic surgeons develop technologies that are manufactured by Wall Street-financed companies. Others participate in the stock market as investors. This study examines the bioengineered skin industry to determine whether it integrates clinical and financial information as Wall Street tenets would predict, and to see whether the financial performance of these companies provides any lessons for practicing plastic surgeons. In efficient markets, the assumptions on which independent financial analysts base their company sales and earnings projections are clinically reasonable, the volatility of a company's stock price does not irrationally differ from that of its industry sector, and the buy/sell recommendations of analysts are roughly congruent. For the companies in this study, these key financial parameters were compared with a benchmark index of 69 biotech companies of similar age and annual revenues (Student's t test). Five bioengineered skin companies were included in the study. Analysts estimated that each company would sell its product to between 24 and 45 percent of its target clinical population. The average stock price volatility was significantly higher for study companies than for those in the benchmark index (p < 0.05). Similarly, buy/sell recommendations of analysts for the study companies were significantly less congruent than those for the benchmark companies (p < 0.05). These results indicate clinically unrealistic projections for market penetration, significantly high price volatility, and significantly high discordance among professional analysts. In all cases, the market is inefficient-an unusual finding on Wall Street. A likely explanation for this market failure is a cycle of poor clinical correlation when assigning sales projections, which in turn leads to price volatility and discordance of buy/sell recommendations. This study's findings have implications for plastic surgeons who develop new technology or who participate in the equities

Education in a rapidly advancing technology: Accelerators and beams

NASA Astrophysics Data System (ADS)

Month, Mel

2000-06-01

The field of accelerators and beams (A&B) is one of today's fast changing technologies. Because university faculties have not been able to keep pace with the associated advancing knowledge, universities have not been able to play their traditional role of educating the scientists and engineers needed to sustain this technology for use in science, industry, commerce, and defense. This problem for A&B is described and addressed. The solution proposed, a type of "distance" education, is the U.S. Particle Accelerator School (USPAS) created in the early 1980s. USPAS provides the universities with a means of serving the education needs of the institutions using A&B, primarily but not exclusively the national laboratories. The field of A&B is briefly summarized. The need for education outside the university framework, the raison d'être for USPAS, the USPAS method, program structure, and curriculum, and particular USPAS-university connections are explained. The management of USPAS is analyzed, including its unique administrative structure, its institutional ties, and its operations, finance, marketing, and governmental relations. USPAS performance over the years is documented and a business assessment is made. Finally, there is a brief discussion of the future potential for this type of educational program, including possible extrapolation to new areas and/or different environments, in particular, its extra-government potential and its international possibilities.

Superconducting accelerator magnet technology in the 21st century: A new paradigm on the horizon?

NASA Astrophysics Data System (ADS)

Gourlay, S. A.

2018-06-01

Superconducting magnets for accelerators were first suggested in the mid-60's and have since become one of the major components of modern particle colliders. Technological progress has been slow but steady for the last half-century, based primarily on Nb-Ti superconductor. That technology has reached its peak with the Large Hadron Collider (LHC). Despite the superior electromagnetic properties of Nb3Sn and adoption by early magnet pioneers, it is just now coming into use in accelerators though it has not yet reliably achieved fields close to the theoretical limit. The discovery of the High Temperature Superconductors (HTS) in the late '80's created tremendous excitement, but these materials, with tantalizing performance at high fields and temperatures, have not yet been successfully developed into accelerator magnet configurations. Thanks to relatively recent developments in both Bi-2212 and REBCO, and a more focused international effort on magnet development, the situation has changed dramatically. Early optimism has been replaced with a reality that could create a new paradigm in superconducting magnet technology. Using selected examples of magnet technology from the previous century to define the context, this paper will describe the possible innovations using HTS materials as the basis for a new paradigm.

Intermittency of acceleration in isotropic turbulence.

PubMed

Lee, Sang; Lee, Changhoon

2005-05-01

The intermittency of acceleration is investigated for isotropic turbulence using direct numerical simulation. Intermittently found acceleration of large magnitude always points towards the rotational axis of a vortex filament, indicating that the intermittency of acceleration is associated with the rotational motion of the vortices that causes centripetal acceleration, which is consistent with the reported result for the near-wall turbulence. Furthermore, investigation on movements of such vortex filaments provides some insights into the dynamics of local dissipation, enstrophy and acceleration. Strong dissipation partially covering the edge of a vortex filament shows weak correlation with enstrophy, while it is strongly correlated with acceleration.

Phase-sensitive dual-inversion recovery for accelerated carotid vessel wall imaging.

PubMed

Bonanno, Gabriele; Brotman, David; Stuber, Matthias

2015-03-01

Dual-inversion recovery (DIR) is widely used for magnetic resonance vessel wall imaging. However, optimal contrast may be difficult to obtain and is subject to RR variability. Furthermore, DIR imaging is time-inefficient and multislice acquisitions may lead to prolonged scanning times. Therefore, an extension of phase-sensitive (PS) DIR is proposed for carotid vessel wall imaging. The statistical distribution of the phase signal after DIR is probed to segment carotid lumens and suppress their residual blood signal. The proposed PS-DIR technique was characterized over a broad range of inversion times. Multislice imaging was then implemented by interleaving the acquisition of 3 slices after DIR. Quantitative evaluation was then performed in healthy adult subjects and compared with conventional DIR imaging. Single-slice PS-DIR provided effective blood-signal suppression over a wide range of inversion times, enhancing wall-lumen contrast and vessel wall conspicuity for carotid arteries. Multislice PS-DIR imaging with effective blood-signal suppression is enabled. A variant of the PS-DIR method has successfully been implemented and tested for carotid vessel wall imaging. This technique removes timing constraints related to inversion recovery, enhances wall-lumen contrast, and enables a 3-fold increase in volumetric coverage at no extra cost in scanning time.

Repetitive nanosecond electron accelerators type URT-1 for radiation technology

NASA Astrophysics Data System (ADS)

Sokovnin, S. Yu.; Balezin, M. E.

2018-03-01

The electron accelerator URT-1М-300 for mobile installation was created for radiation disinfecting to correct drawbacks that were found the URT-1M electron accelerator operation (the accelerating voltage up to 1 МV, repetition rate up to 300 pps, electron beam size 400 × 100 mm, the pulse width about 100 ns). Accelerator configuration was changed that allowed to reduce significantly by 20% tank volume with oil where is placed the system of formation high-voltage pulses, thus the average power of the accelerator is increased by 6 times at the expense of increase in pulses repetition rate. Was created the system of the computerized monitoring parameters (output parameters and thermal mode) and remote control of the accelerator (charge voltage, pulse repetition rate), its elements and auxiliary systems (heat of the thyratron, vacuum system), the remote control panel is connected to the installation by the fiber-optical channel, what lightens the work for service personnel. For generating an electron beam up to 400 mm wide there are used metal- ceramic] and metal-dielectric cold cathodes of several emission elements (plates) with a non-uniform distribution of the electron beam current density on the output foil ± 15%. It was found that emission drop of both type of cathodes, during the operation at the high repetition rate (100 pps) is substantial at the beginning of the process, and then proceeds rather slowly that allows for continuous operation up to 40 h. Experiments showed that linear dependence of the voltage and a signal from the pin-diode remains within the range of the charge voltage 45-65 kV. Thus, voltage increases from 690 to 950 kV, and the signal from the pin-diode - from (2,8-4,6)*104 Gy/s. It allows to select electron energy quite precisely with consideration of the radiation technology requirements.

Extraordinary tools for extraordinary science: the impact of SciDAC on accelerator science and technology

NASA Astrophysics Data System (ADS)

Ryne, Robert D.

2006-09-01

Particle accelerators are among the most complex and versatile instruments of scientific exploration. They have enabled remarkable scientific discoveries and important technological advances that span all programs within the DOE Office of Science (DOE/SC). The importance of accelerators to the DOE/SC mission is evident from an examination of the DOE document, ''Facilities for the Future of Science: A Twenty-Year Outlook.'' Of the 28 facilities listed, 13 involve accelerators. Thanks to SciDAC, a powerful suite of parallel simulation tools has been developed that represent a paradigm shift in computational accelerator science. Simulations that used to take weeks or more now take hours, and simulations that were once thought impossible are now performed routinely. These codes have been applied to many important projects of DOE/SC including existing facilities (the Tevatron complex, the Relativistic Heavy Ion Collider), facilities under construction (the Large Hadron Collider, the Spallation Neutron Source, the Linac Coherent Light Source), and to future facilities (the International Linear Collider, the Rare Isotope Accelerator). The new codes have also been used to explore innovative approaches to charged particle acceleration. These approaches, based on the extremely intense fields that can be present in lasers and plasmas, may one day provide a path to the outermost reaches of the energy frontier. Furthermore, they could lead to compact, high-gradient accelerators that would have huge consequences for US science and technology, industry, and medicine. In this talk I will describe the new accelerator modeling capabilities developed under SciDAC, the essential role of multi-disciplinary collaboration with applied mathematicians, computer scientists, and other IT experts in developing these capabilities, and provide examples of how the codes have been used to support DOE/SC accelerator projects.

Accelerating Project and Process Improvement using Advanced Software Simulation Technology: From the Office to the Enterprise

DTIC Science & Technology

2010-04-29

Technology: From the Office Larry Smith Software Technology Support Center to the Enterprise 517 SMXS/MXDEA 6022 Fir Avenue Hill AFB, UT 84056 801...2010 to 00-00-2010 4. TITLE AND SUBTITLE Accelerating Project and Process Improvement using Advanced Software Simulation Technology: From the Office to

A new type of accelerator power supply based on voltage-type space vector PWM rectification technology

NASA Astrophysics Data System (ADS)

Wu, Fengjun; Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen; Cui, Yuan; Yan, Hongbin; Zhang, Huajian; Wang, Bin; Li, Xiaohui

2016-08-01

To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply.

ACCELERATION INTEGRATING MEANS

DOEpatents

Wilkes, D.F.

1961-08-29

An acceleration responsive device is described. A housing has at one end normally open electrical contacts and contains a piston system with a first part of non-magnetic material having metering orifices in the side walls for forming an air bearing between it and the walls of the housing; this first piston part is normally held against the other end of the housing from the noted contacts by a second piston or reset part. The reset part is of partly magnetic material, is separable from the flrst piston part, and is positioned within the housing intermediate the contacts and the first piston part. A magnet carried by the housing imposes a retaining force upon the reset part, along with a helical compression spring that is between the reset part and the end with the contacts. When a predetermined acceleration level is attained, the reset part overcomes the bias or retaining force provided by the magnet and the spring'' snaps'' into a depression in the housing adjacent the contacts. The first piston part is then free to move toward the contacts with its movement responsive tc acceleration forces and the metering orifices. (AEC)

Photoelectron linear accelerator for producing a low emittance polarized electron beam

DOEpatents

Yu, David U.; Clendenin, James E.; Kirby, Robert E.

2004-06-01

A photoelectron linear accelerator for producing a low emittance polarized electric beam. The accelerator includes a tube having an inner wall, the inner tube wall being coated by a getter material. A portable, or demountable, cathode plug is mounted within said tube, the surface of said cathode having a semiconductor material formed thereon.

Accelerating Technology Development through Integrated Computation and Experimentation

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

Shekhawat, Dushyant; Srivastava, Rameshwar D.; Ciferno, Jared

2013-08-15

This special section of Energy & Fuels comprises a selection of papers presented at the topical conference “Accelerating Technology Development through Integrated Computation and Experimentation”, sponsored and organized by the United States Department of Energy’s National Energy Technology Laboratory (NETL) as part of the 2012 American Institute of Chemical Engineers (AIChE) Annual Meeting held in Pittsburgh, PA, Oct 28-Nov 2, 2012. That topical conference focused on the latest research and development efforts in five main areas related to fossil energy, with each area focusing on the utilization of both experimental and computational approaches: (1) gas separations (membranes, sorbents, and solventsmore » for CO{sub 2}, H{sub 2}, and O{sub 2} production), (2) CO{sub 2} utilization (enhanced oil recovery, chemical production, mineralization, etc.), (3) carbon sequestration (flow in natural systems), (4) advanced power cycles (oxy-combustion, chemical looping, gasification, etc.), and (5) fuel processing (H{sub 2} production for fuel cells).« less

Accelerating the commercialization of university technologies for military healthcare applications: the role of the proof of concept process

NASA Astrophysics Data System (ADS)

Ochoa, Rosibel; DeLong, Hal; Kenyon, Jessica; Wilson, Eli

2011-06-01

The von Liebig Center for Entrepreneurism and Technology Advancement at UC San Diego (vonliebig.ucsd.edu) is focused on accelerating technology transfer and commercialization through programs and education on entrepreneurism. Technology Acceleration Projects (TAPs) that offer pre-venture grants and extensive mentoring on technology commercialization are a key component of its model which has been developed over the past ten years with the support of a grant from the von Liebig Foundation. In 2010, the von Liebig Entrepreneurism Center partnered with the U.S. Army Telemedicine and Advanced Technology Research Center (TATRC), to develop a regional model of Technology Acceleration Program initially focused on military research to be deployed across the nation to increase awareness of military medical needs and to accelerate the commercialization of novel technologies to treat the patient. Participants to these challenges are multi-disciplinary teams of graduate students and faculty in engineering, medicine and business representing universities and research institutes in a region, selected via a competitive process, who receive commercialization assistance and funding grants to support translation of their research discoveries into products or services. To validate this model, a pilot program focused on commercialization of wireless healthcare technologies targeting campuses in Southern California has been conducted with the additional support of Qualcomm, Inc. Three projects representing three different universities in Southern California were selected out of forty five applications from ten different universities and research institutes. Over the next twelve months, these teams will conduct proof of concept studies, technology development and preliminary market research to determine the commercial feasibility of their technologies. This first regional program will help build the needed tools and processes to adapt and replicate this model across other regions in the

Classroom Wall Charts and Biblical History: A Study of Educational Technology in Elementary Schools in Late Nineteenth- and Early Twentieth-Century Sweden

ERIC Educational Resources Information Center

Evertsson, Jakob

2014-01-01

This article considers the emergence of classroom wall charts as a teaching technology in Swedish elementary schools in the late nineteenth and early twentieth centuries, using Biblical history teaching as an example. There has been some work done internationally on wall charts as an instructional technology, but few studies have looked at their…

Plasma-wall interaction in laser inertial fusion reactors: novel proposals for radiation tests of first wall materials

NASA Astrophysics Data System (ADS)

Alvarez Ruiz, J.; Rivera, A.; Mima, K.; Garoz, D.; Gonzalez-Arrabal, R.; Gordillo, N.; Fuchs, J.; Tanaka, K.; Fernández, I.; Briones, F.; Perlado, J.

2012-12-01

Dry-wall laser inertial fusion (LIF) chambers will have to withstand strong bursts of fast charged particles which will deposit tens of kJ m-2 and implant more than 1018 particles m-2 in a few microseconds at a repetition rate of some Hz. Large chamber dimensions and resistant plasma-facing materials must be combined to guarantee the chamber performance as long as possible under the expected threats: heating, fatigue, cracking, formation of defects, retention of light species, swelling and erosion. Current and novel radiation resistant materials for the first wall need to be validated under realistic conditions. However, at present there is a lack of facilities which can reproduce such ion environments. This contribution proposes the use of ultra-intense lasers and high-intense pulsed ion beams (HIPIB) to recreate the plasma conditions in LIF reactors. By target normal sheath acceleration, ultra-intense lasers can generate very short and energetic ion pulses with a spectral distribution similar to that of the inertial fusion ion bursts, suitable to validate fusion materials and to investigate the barely known propagation of those bursts through background plasmas/gases present in the reactor chamber. HIPIB technologies, initially developed for inertial fusion driver systems, provide huge intensity pulses which meet the irradiation conditions expected in the first wall of LIF chambers and thus can be used for the validation of materials too.

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.

Wind tunnel wall interference

NASA Technical Reports Server (NTRS)

Newman, Perry A.; Mineck, Raymond E.; Barnwell, Richard W.; Kemp, William B., Jr.

1986-01-01

About a decade ago, interest in alleviating wind tunnel wall interference was renewed by advances in computational aerodynamics, concepts of adaptive test section walls, and plans for high Reynolds number transonic test facilities. Selection of NASA Langley cryogenic concept for the National Transonic Facility (NTF) tended to focus the renewed wall interference efforts. A brief overview and current status of some Langley sponsored transonic wind tunnel wall interference research are presented. Included are continuing efforts in basic wall flow studies, wall interference assessment/correction procedures, and adaptive wall technology.

Education in a rapidly advancing technology: Accelerators and beams

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

Month, Mel

2000-06-01

The field of accelerators and beams (A and B) is one of today's fast changing technologies. Because university faculties have not been able to keep pace with the associated advancing knowledge, universities have not been able to play their traditional role of educating the scientists and engineers needed to sustain this technology for use in science, industry, commerce, and defense. This problem for A and B is described and addressed. The solution proposed, a type of ''distance'' education, is the U.S. Particle Accelerator School (USPAS) created in the early 1980s. USPAS provides the universities with a means of serving themore » education needs of the institutions using A and B, primarily but not exclusively the national laboratories. The field of A and B is briefly summarized. The need for education outside the university framework, the raison d'etre for USPAS, the USPAS method, program structure, and curriculum, and particular USPAS-university connections are explained. The management of USPAS is analyzed, including its unique administrative structure, its institutional ties, and its operations, finance, marketing, and governmental relations. USPAS performance over the years is documented and a business assessment is made. Finally, there is a brief discussion of the future potential for this type of educational program, including possible extrapolation to new areas and/or different environments, in particular, its extra-government potential and its international possibilities. (c) 2000 American Association of Physics Teachers.« less

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

Accelerating the deployment of energy efficient and renewable energy technologies in South Africa

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

Shickman, Kurt

Purpose of the project was to accelerate the deployment of energy efficient and renewable energy technologies in South Africa. Activities were undertaken to reduce barriers to deployment by improving product awareness for the South African market; market and policy intelligence for U.S. manufacturers; product/service availability; local technical capacity at the workforce, policymaker and expert levels; and ease of conducting business for these technologies/services in the South African market.

Dielectric-wall linear accelerator with a high voltage fast rise time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators

DOEpatents

Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

1998-01-01

A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface.

A Generalized Wall Function

NASA Technical Reports Server (NTRS)

Shih, Tsan-Hsing; Povinelli, Louis A.; Liu, Nan-Suey; Potapczuk, Mark G.; Lumley, J. L.

1999-01-01

The asymptotic solutions, described by Tennekes and Lumley (1972), for surface flows in a channel, pipe or boundary layer at large Reynolds numbers are revisited. These solutions can be extended to more complex flows such as the flows with various pressure gradients, zero wall stress and rough surfaces, etc. In computational fluid dynamics (CFD), these solutions can be used as the boundary conditions to bridge the near-wall region of turbulent flows so that there is no need to have the fine grids near the wall unless the near-wall flow structures are required to resolve. These solutions are referred to as the wall functions. Furthermore, a generalized and unified law of the wall which is valid for whole surface layer (including viscous sublayer, buffer layer and inertial sublayer) is analytically constructed. The generalized law of the wall shows that the effect of both adverse and favorable pressure gradients on the surface flow is very significant. Such as unified wall function will be useful not only in deriving analytic expressions for surface flow properties but also bringing a great convenience for CFD methods to place accurate boundary conditions at any location away from the wall. The extended wall functions introduced in this paper can be used for complex flows with acceleration, deceleration, separation, recirculation and rough surfaces.

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.

7. INTERIOR, MAIN GARAGE, SOUTHERN WALL, FROM CLOSE TO WALL, ...

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

7. INTERIOR, MAIN GARAGE, SOUTHERN WALL, FROM CLOSE TO WALL, LOOKING SOUTH, SHOWING 'GAMEWELL' FIRE ALARM TAPE CONTROL SYSTEM (TECHNOLOGY CIRCA 1910) AT CENTER, AND ENTRY TO OFFICE AT FAR RIGHT. - Oakland Naval Supply Center, Firehouse, East of Fourth Street, between A & B Streets, Oakland, Alameda County, CA

Development of laser-based technology for the routine first wall diagnostic on the tokamak EAST: LIBS and LIAS

NASA Astrophysics Data System (ADS)

Hu, Z.; Gierse, N.; Li, C.; Liu, P.; Zhao, D.; Sun, L.; Oelmann, J.; Nicolai, D.; Wu, D.; Wu, J.; Mao, H.; Ding, F.; Brezinsek, S.; Liang, Y.; Ding, H.; Luo, G.; Linsmeier, C.; EAST Team

2017-12-01

A laser based method combined with spectroscopy, such as laser-induced breakdown spectroscopy (LIBS) and laser-induced ablation spectroscopy (LIAS), is a promising technology for plasma-wall interaction studies. In this work, we report the development of in situ laser-based diagnostics (LIBS and LIAS) for the assessment of static and dynamic fuel retention on the first wall without removing the tiles between and during plasma discharges in the Experimental Advanced Superconducting Tokamak (EAST). The fuel retention on the first wall was measured after different wall conditioning methods and daily plasma discharges by in situ LIBS. The result indicates that the LIBS can be a useful tool to predict the wall condition in EAST. With the successful commissioning of a refined timing system for LIAS, an in situ approach to investigate fuel retention is proposed.

Dielectric-wall linear accelerator with a high voltage fast rise time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators

DOEpatents

Caporaso, G.J.; Sampayan, S.E.; Kirbie, H.C.

1998-10-13

A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface. 12 figs.

Harnessing collaborative technology to accelerate achievement of chronic disease management objectives for Canada.

PubMed

Thompson, Leslee J; Healey, Lindsay; Falk, Will

2007-01-01

Morgan and colleagues put forth a call to action for the transformation of the Canadian healthcare system through the adoption of a national chronic disease prevention and management (CDPM) strategy. They offer examples of best practices and national solutions including investment in clinical information technologies to help support improved care and outcomes. Although we acknowledge that the authors propose CDPM solutions that are headed in the right direction, more rapid deployment of solutions that harness the potential of advanced collaborative technologies is required. We provide examples of how technologies that exist today can help to accelerate the achievement of some key CDPM objectives.

Generalized Wall Function for Complex Turbulent Flows

NASA Technical Reports Server (NTRS)

Shih, Tsan-Hsing; Povinelli, Louis A.; Liu, Nan-Suey; Chen, Kuo-Huey

2000-01-01

A generalized wall function was proposed by Shih et al., (1999). It accounts the effect of pressure gradients on the flow near the wall. Theory shows that the effect of pressure gradients on the flow in the inertial sublayer is very significant and the standard wall function should be replaced by a generalized wall function. Since the theory is also valid for boundary layer flows toward separation, the generalized wall function may be applied to complex turbulent flows with acceleration, deceleration, separation and recirculation. This paper is to verify the generalized wall function with numerical simulations for boundary layer flows with various adverse and favorable pressure gradients, including flows about to separate. Furthermore, a general procedure of implementation of the generalized wall function for National Combustion Code (NCC) is described, it can be applied to both structured and unstructured CFD codes.

Spaces of the possible: universal Darwinism and the wall between technological and biological innovation

PubMed Central

Wagner, Andreas; Rosen, William

2014-01-01

Innovations in biological evolution and in technology have many common features. Some of them involve similar processes, such as trial and error and horizontal information transfer. Others describe analogous outcomes such as multiple independent origins of similar innovations. Yet others display similar temporal patterns such as episodic bursts of change separated by periods of stasis. We review nine such commonalities, and propose that the mathematical concept of a space of innovations, discoveries or designs can help explain them. This concept can also help demolish a persistent conceptual wall between technological and biological innovation. PMID:24850903

Universality of accelerating change

NASA Astrophysics Data System (ADS)

Eliazar, Iddo; Shlesinger, Michael F.

2018-03-01

On large time scales the progress of human technology follows an exponential growth trend that is termed accelerating change. The exponential growth trend is commonly considered to be the amalgamated effect of consecutive technology revolutions - where the progress carried in by each technology revolution follows an S-curve, and where the aging of each technology revolution drives humanity to push for the next technology revolution. Thus, as a collective, mankind is the 'intelligent designer' of accelerating change. In this paper we establish that the exponential growth trend - and only this trend - emerges universally, on large time scales, from systems that combine together two elements: randomness and amalgamation. Hence, the universal generation of accelerating change can be attained by systems with no 'intelligent designer'.

Exposure to chronic alcohol accelerates development of wall stress and eccentric remodeling in rats with volume overload.

PubMed

Mouton, Alan J; Ninh, Van K; El Hajj, Elia C; El Hajj, Milad C; Gilpin, Nicholas W; Gardner, Jason D

2016-08-01

expression, whereas this effect was not observed in rats with VO+EtOH. In conclusion, chronic EtOH accelerates the development of elevated wall stress and promotes early eccentric remodeling in rats with VO. Our data indicate that these effects may be due to disruptions in compensatory hypertrophy and extracellular matrix remodeling in response to volume overload. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optical Microfiber Technology for Current, Temperature, Acceleration, Acoustic, Humidity and Ultraviolet Light Sensing

PubMed Central

Lancaster, David G.; Monro, Tanya M.

2017-01-01

Optical microfibers possess excellent optical and mechanical properties that have been exploited for sensing. We highlight the authors’ recent work in the areas of current, temperature, acceleration, acoustic, humidity and ultraviolet-light sensing based on this exquisite technology, and the advantages and challenges of using optical microfibers are discussed. PMID:29283414

Theoretical and technological building blocks for an innovation accelerator

NASA Astrophysics Data System (ADS)

van Harmelen, F.; Kampis, G.; Börner, K.; van den Besselaar, P.; Schultes, E.; Goble, C.; Groth, P.; Mons, B.; Anderson, S.; Decker, S.; Hayes, C.; Buecheler, T.; Helbing, D.

2012-11-01

Modern science is a main driver of technological innovation. The efficiency of the scientific system is of key importance to ensure the competitiveness of a nation or region. However, the scientific system that we use today was devised centuries ago and is inadequate for our current ICT-based society: the peer review system encourages conservatism, journal publications are monolithic and slow, data is often not available to other scientists, and the independent validation of results is limited. The resulting scientific process is hence slow and sloppy. Building on the Innovation Accelerator paper by Helbing and Balietti [1], this paper takes the initial global vision and reviews the theoretical and technological building blocks that can be used for implementing an innovation (in first place: science) accelerator platform driven by re-imagining the science system. The envisioned platform would rest on four pillars: (i) Redesign the incentive scheme to reduce behavior such as conservatism, herding and hyping; (ii) Advance scientific publications by breaking up the monolithic paper unit and introducing other building blocks such as data, tools, experiment workflows, resources; (iii) Use machine readable semantics for publications, debate structures, provenance etc. in order to include the computer as a partner in the scientific process, and (iv) Build an online platform for collaboration, including a network of trust and reputation among the different types of stakeholders in the scientific system: scientists, educators, funding agencies, policy makers, students and industrial innovators among others. Any such improvements to the scientific system must support the entire scientific process (unlike current tools that chop up the scientific process into disconnected pieces), must facilitate and encourage collaboration and interdisciplinarity (again unlike current tools), must facilitate the inclusion of intelligent computing in the scientific process, must facilitate

Accelerated and Improved Differentiation of Retinal Organoids from Pluripotent Stem Cells in Rotating-Wall Vessel Bioreactors.

PubMed

DiStefano, Tyler; Chen, Holly Yu; Panebianco, Christopher; Kaya, Koray Dogan; Brooks, Matthew J; Gieser, Linn; Morgan, Nicole Y; Pohida, Tom; Swaroop, Anand

2018-01-09

Pluripotent stem cells can be differentiated into 3D retinal organoids, with major cell types self-patterning into a polarized, laminated architecture. In static cultures, organoid development may be hindered by limitations in diffusion of oxygen and nutrients. Herein, we report a bioprocess using rotating-wall vessel (RWV) bioreactors to culture retinal organoids derived from mouse pluripotent stem cells. Organoids in RWV demonstrate enhanced proliferation, with well-defined morphology and improved differentiation of neurons including ganglion cells and S-cone photoreceptors. Furthermore, RWV organoids at day 25 (D25) reveal similar maturation and transcriptome profile as those at D32 in static culture, closely recapitulating spatiotemporal development of postnatal day 6 mouse retina in vivo. Interestingly, however, retinal organoids do not differentiate further under any in vitro condition tested here, suggesting additional requirements for functional maturation. Our studies demonstrate that bioreactors can accelerate and improve organoid growth and differentiation for modeling retinal disease and evaluation of therapies. Published by Elsevier Inc.

Testing Done for Lorentz Force Accelerators and Electrodeless Propulsion Technology Development

NASA Technical Reports Server (NTRS)

Pencil, Eric J.; Gilland, James H.; Arrington, Lynn A.; Kamhawi, Hani

2004-01-01

The NASA Glenn Research Center is developing Lorentz force accelerators and electrodeless plasma propulsion for a wide variety of space applications. These applications range from precision control of formation-flying spacecraft to primary propulsion for very high power interplanetary spacecraft. The specific thruster technologies being addressed are pulsed plasma thrusters, magnetoplasmadynamic thrusters, and helicon-electron cyclotron resonance acceleration thrusters. The pulsed plasma thruster mounted on the Earth Observing-1 spacecraft was operated successfully in orbit in 2002. The two-axis thruster system is fully incorporated in the attitude determination and control system and is being used to automatically counteract disturbances in the pitch axis of the spacecraft. Recent on-orbit operations have focused on extended operations to add flight operation time to the total accumulated thruster life. The results of the experiments pave the way for electric propulsion applications on future Earth-imaging satellites.

Cell Wall Assembly and Intracellular Trafficking in Plant Cells Are Directly Affected by Changes in the Magnitude of Gravitational Acceleration

PubMed Central

Chebli, Youssef; Pujol, Lauranne; Shojaeifard, Anahid; Brouwer, Iman; van Loon, Jack J. W. A.; Geitmann, Anja

2013-01-01

Plants are able to sense the magnitude and direction of gravity. This capacity is thought to reside in selected cell types within the plant body that are equipped with specialized organelles called statoliths. However, most plant cells do not possess statoliths, yet they respond to changes in gravitational acceleration. To understand the effect of gravity on the metabolism and cellular functioning of non-specialized plant cells, we investigated a rapidly growing plant cell devoid of known statoliths and without gravitropic behavior, the pollen tube. The effects of hyper-gravity and omnidirectional exposure to gravity on intracellular trafficking and on cell wall assembly were assessed in Camellia pollen tubes, a model system with highly reproducible growth behavior in vitro. Using an epi-fluorescence microscope mounted on the Large Diameter Centrifuge at the European Space Agency, we were able to demonstrate that vesicular trafficking is reduced under hyper-gravity conditions. Immuno-cytochemistry confirmed that both in hyper and omnidirectional gravity conditions, the characteristic spatial profiles of cellulose and callose distribution in the pollen tube wall were altered, in accordance with a dose-dependent effect on pollen tube diameter. Our findings suggest that in response to gravity induced stress, the pollen tube responds by modifying cell wall assembly to compensate for the altered mechanical load. The effect was reversible within few minutes demonstrating that the pollen tube is able to quickly adapt to changing stress conditions. PMID:23516452

Accelerated construction

DOT National Transportation Integrated Search

2004-01-01

Accelerated Construction Technology Transfer (ACTT) is a strategic process that uses various innovative techniques, strategies, and technologies to minimize actual construction time, while enhancing quality and safety on today's large, complex multip...

Skyrmion domain wall collision and domain wall-gated skyrmion logic

NASA Astrophysics Data System (ADS)

Xing, Xiangjun; Pong, Philip W. T.; Zhou, Yan

2016-08-01

Skyrmions and domain walls are significant spin textures of great technological relevance to magnetic memory and logic applications, where they can be used as carriers of information. The unique topology of skyrmions makes them display emergent dynamical properties as compared with domain walls. Some studies have demonstrated that the two topologically inequivalent magnetic objects could be interconverted by using cleverly designed geometric structures. Here, we numerically address the skyrmion domain wall collision in a magnetic racetrack by introducing relative motion between the two objects based on a specially designed junction. An electric current serves as the driving force that moves a skyrmion toward a trapped domain wall pair. We see different types of collision dynamics depending on the driving parameters. Most importantly, the modulation of skyrmion transport using domain walls is realized in this system, allowing a set of domain wall-gated logical NOT, NAND, and NOR gates to be constructed. This work provides a skyrmion-based spin-logic architecture that is fully compatible with racetrack memories.

Spaces of the possible: universal Darwinism and the wall between technological and biological innovation.

PubMed

Wagner, Andreas; Rosen, William

2014-08-06

Innovations in biological evolution and in technology have many common features. Some of them involve similar processes, such as trial and error and horizontal information transfer. Others describe analogous outcomes such as multiple independent origins of similar innovations. Yet others display similar temporal patterns such as episodic bursts of change separated by periods of stasis. We review nine such commonalities, and propose that the mathematical concept of a space of innovations, discoveries or designs can help explain them. This concept can also help demolish a persistent conceptual wall between technological and biological innovation. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Strength of unbonded post-tensioned walls.

DOT National Transportation Integrated Search

2014-08-01

Post-tensioned masonry wall (PT-MW) is an ideal candidate for accelerating the construction of sound barriers in highways. PT-MWs : have been in use for a while in buildings; however, there has been no rigorous single-study in the U. S. about in-plan...

Linear Accelerator (LINAC)

MedlinePlus

... equipment? How is safety ensured? What is this equipment used for? A linear accelerator (LINAC) is the ... Therapy (SBRT) . top of page How does the equipment work? The linear accelerator uses microwave technology (similar ...

Clustering Of Left Ventricular Wall Motion Patterns

NASA Astrophysics Data System (ADS)

Bjelogrlic, Z.; Jakopin, J.; Gyergyek, L.

1982-11-01

A method for detection of wall regions with similar motion was presented. A model based on local direction information was used to measure the left ventricular wall motion from cineangiographic sequence. Three time functions were used to define segmental motion patterns: distance of a ventricular contour segment from the mean contour, the velocity of a segment and its acceleration. Motion patterns were clustered by the UPGMA algorithm and by an algorithm based on K-nearest neighboor classification rule.

Electromagnetic approaches to wall characterization, wall mitigation, and antenna design for through-the-wall radar systems

NASA Astrophysics Data System (ADS)

Thajudeen, Christopher

Through-the-wall imaging (TWI) is a topic of current interest due to its wide range of public safety, law enforcement, and defense applications. Among the various available technologies such as, acoustic, thermal, and optical imaging, which can be employed to sense and image targets of interest, electromagnetic (EM) imaging, in the microwave frequency bands, is the most widely utilized technology and has been at the forefront of research in recent years. The primary objectives for any Through-the-Wall Radar Imaging (TWRI) system are to obtain a layout of the building and/or inner rooms, detect if there are targets of interest including humans or weapons, determine if there are countermeasures being employed to further obscure the contents of a building or room of interest, and finally to classify the detected targets. Unlike conventional radar scenarios, the presence of walls, made of common construction materials such as brick, drywall, plywood, cinder block, and solid concrete, adversely affects the ability of any conventional imaging technique to properly image targets enclosed within building structures as the propagation through the wall can induce shadowing effects on targets of interest which may result in image degradation, errors in target localization, and even complete target masking. For many applications of TWR systems, the wall ringing signals are strong enough to mask the returns from targets not located a sufficient distance behind the wall, beyond the distance of the wall ringing, and thus without proper wall mitigation, target detection becomes extremely difficult. The results presented in this thesis focus on the development of wall parameter estimation, and intra-wall and wall-type characterization techniques for use in both the time and frequency domains as well as analysis of these techniques under various real world scenarios such as reduced system bandwidth scenarios, various wall backing scenarios, the case of inhomogeneous walls, presence

Acceleration profile of an acrobatic act during training and shows using wearable technology.

PubMed

Barker, Leland; Burnstein, Bryan; Mercer, John

2018-05-24

The purpose of this study was to describe the mechanical characteristics of a trampoline circus act and its individual tracks performed in training and shows using a tri-axial accelerometer. A track is an artist's specific role within a choreographed act. Seven male acrobats performed their trampoline act during training and shows while wearing a triaxial accelerometer and reported ratings of perceived exertion (RPE) after each trial. Average acceleration (AVG), root mean square (RMS), root mean to the fourth (RM4), time spent in specific acceleration ranges and RPE were measured/recorded from training and show acts. Paired t-tests compared dependent variables between training and show. Acceleration AVG, RMS and RM4 were significantly higher (p < 0.05) in training than show. RPE was significantly higher (p < 0.05) in show than training. No significant differences existed in time spent in any of the acceleration ranges between training and show. GPS devices have been used to manage workloads in field sports but are inoperable in theatres. But, inertial measurements may be an effective alternative to describe mechanical demands in theatre or arena environments. Wearable technology may be useful to coaches to improve understanding of track demands to manage artist workloads.

Overview of Accelerator Applications in Energy

NASA Astrophysics Data System (ADS)

Garnett, Robert W.; Sheffield, Richard L.

An overview of the application of accelerators and accelerator technology in energy is presented. Applications span a broad range of cost, size, and complexity and include large-scale systems requiring high-power or high-energy accelerators to drive subcritical reactors for energy production or waste transmutation, as well as small-scale industrial systems used to improve oil and gas exploration and production. The enabling accelerator technologies will also be reviewed and future directions discussed.

Air film cooling in a nonadiabatic wall conical nozzle.

NASA Technical Reports Server (NTRS)

Boldman, D. R.; Papell, S. S.; Ehlers, R. C.

1972-01-01

Experimental data for an air-film cooled conical nozzle operating with a heated-air main stream and a water-cooled wall confirm the validity of Lieu's (1964) method for correlating film cooling data in the accelerated flow of a nonadiabatic-wall nozzle. The film cooling effectiveness modified for nonadiabatic walls by Lieu can be used to correlate film cooling under the condition that the main-stream to coolant velocity ratio at the slot is about 1. Such a ratio provides the optimum cooling effectiveness.

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

Accelerator physics and technology challenges of very high energy hadron colliders

NASA Astrophysics Data System (ADS)

Shiltsev, Vladimir D.

2015-08-01

High energy hadron colliders have been in the forefront of particle physics for more than three decades. At present, international particle physics community considers several options for a 100 TeV proton-proton collider as a possible post-LHC energy frontier facility. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This paper briefly reviews the accelerator physics and technology challenges of the future very high energy colliders and outlines the areas of required research and development towards their technical and financial feasibility.

Accelerator physics and technology challenges of very high energy hadron colliders

DOE PAGES

Shiltsev, Vladimir D.

2015-08-20

High energy hadron colliders have been in the forefront of particle physics for more than three decades. At present, international particle physics community considers several options for a 100 TeV proton–proton collider as a possible post-LHC energy frontier facility. The method of colliding beams has not fully exhausted its potential but has slowed down considerably in its progress. This article briefly reviews the accelerator physics and technology challenges of the future very high energy colliders and outlines the areas of required research and development towards their technical and financial feasibility.

12th European Conference on Accelerators in Applied Research and Technology

NASA Astrophysics Data System (ADS)

Sajavaara, Timo; Tarvainen, Olli; Javanainen, Arto; Räisänen, Jyrki

2017-09-01

The 12th European Conference on Accelerators in Applied Research and Technology was organized by Department of Physics on the 3rd -8th July 2016 in the Agora building of the University of Jyväskylä in Finland. This was the first time ECAART was held in Nordic countries. There were in total 141 participants from 31 countries and six industrial exhibitors. The largest foreign delegation was from Japan with 25 participants. The scientific programme included 13 invited lectures, 29 oral and 112 poster presentations. There were altogether 14 exhibitors and sponsors.

Advanced Accelerators for Medical Applications

NASA Astrophysics Data System (ADS)

Uesaka, Mitsuru; Koyama, Kazuyoshi

We review advanced accelerators for medical applications with respect to the following key technologies: (i) higher RF electron linear accelerator (hereafter “linac”); (ii) optimization of alignment for the proton linac, cyclotron and synchrotron; (iii) superconducting magnet; (iv) laser technology. Advanced accelerators for medical applications are categorized into two groups. The first group consists of compact medical linacs with high RF, cyclotrons and synchrotrons downsized by optimization of alignment and superconducting magnets. The second group comprises laser-based acceleration systems aimed of medical applications in the future. Laser plasma electron/ion accelerating systems for cancer therapy and laser dielectric accelerating systems for radiation biology are mentioned. Since the second group has important potential for a compact system, the current status of the established energy and intensity and of the required stability are given.

Advanced Accelerators for Medical Applications

NASA Astrophysics Data System (ADS)

Uesaka, Mitsuru; Koyama, Kazuyoshi

We review advanced accelerators for medical applications with respect to the following key technologies: (i) higher RF electron linear accelerator (hereafter "linac"); (ii) optimization of alignment for the proton linac, cyclotron and synchrotron; (iii) superconducting magnet; (iv) laser technology. Advanced accelerators for medical applications are categorized into two groups. The first group consists of compact medical linacs with high RF, cyclotrons and synchrotrons downsized by optimization of alignment and superconducting magnets. The second group comprises laserbased acceleration systems aimed of medical applications in the future. Laser plasma electron/ion accelerating systems for cancer therapy and laser dielectric accelerating systems for radiation biology are mentioned. Since the second group has important potential for a compact system, the current status of the established energy and intensity and of the required stability are given.

Development of Gravity Acceleration Measurement Using Simple Harmonic Motion Pendulum Method Based on Digital Technology and Photogate Sensor

NASA Astrophysics Data System (ADS)

Yulkifli; Afandi, Zurian; Yohandri

2018-04-01

Development of gravitation acceleration measurement using simple harmonic motion pendulum method, digital technology and photogate sensor has been done. Digital technology is more practical and optimizes the time of experimentation. The pendulum method is a method of calculating the acceleration of gravity using a solid ball that connected to a rope attached to a stative pole. The pendulum is swung at a small angle resulted a simple harmonic motion. The measurement system consists of a power supply, Photogate sensors, Arduino pro mini and seven segments. The Arduino pro mini receives digital data from the photogate sensor and processes the digital data into the timing data of the pendulum oscillation. The calculation result of the pendulum oscillation time is displayed on seven segments. Based on measured data, the accuracy and precision of the experiment system are 98.76% and 99.81%, respectively. Based on experiment data, the system can be operated in physics experiment especially in determination of the gravity acceleration.

Conducting wall Hall thrusters in magnetic shielding and standard configurations

NASA Astrophysics Data System (ADS)

Grimaud, Lou; Mazouffre, Stéphane

2017-07-01

Traditional Hall thrusters are fitted with boron nitride dielectric discharge channels that confine the plasma discharge. Wall properties have significant effects on the performances and stability of the thrusters. In magnetically shielded thrusters, interactions between the plasma and the walls are greatly reduced, and the potential drop responsible for ion acceleration is situated outside the channel. This opens the way to the utilization of alternative materials for the discharge channel. In this work, graphite walls are compared to BN-SiO2 walls in the 200 W magnetically shielded ISCT200-MS and the unshielded ISCT200-US Hall thrusters. The magnetically shielded thruster shows no significant change in the discharge current mean value and oscillations, while the unshielded thruster's discharge current increases by 25% and becomes noticeably less stable. The electric field profile is also investigated through laser spectroscopy, and no significant difference is recorded between the ceramic and graphite cases for the shielded thruster. The unshielded thruster, on the other hand, has its acceleration region shifted 15% of the channel length downstream. Lastly, the plume profile is measured with planar probes fitted with guard rings. Once again the material wall has little influence on the plume characteristics in the shielded thruster, while the unshielded one is significantly affected.

Magnetic booster fast ignition macron accelerator

NASA Astrophysics Data System (ADS)

Winterberg, F.

2006-11-01

A new fast ignition scheme was recently proposed where the ignition is done by the impact of a small solid projectile accelerated to velocities in excess of 108cm/s, with the acceleration done in two steps: first, by laser ablation of a flyer plate, and second by injecting the flyer plate into a conical duct. The two principal difficulties of this scheme are as follows: first, the required large mass ratio for the laser ablation rocket propelled flyer plate, and second, the Rayleigh-Taylor instability of the flyer plate during its implosive compression in the conical duct. To overcome these difficulties, it is suggested to accelerate a projectile by a magnetic fusion booster stage, made up of a dense, wall-confined magnetized plasma brought to thermonuclear temperatures. After ignition, this plasma undergoes a thermonuclear excursion greatly increasing its pressure, resulting in the explosion of a weakened segment of the wall, with the segment becoming a fast moving projectile. The maximum velocity this projectile can reach is the velocity of sound of the booster stage plasma, which at a temperature of 108K is of the order 108cm/s.

USPAS | U.S. Particle Accelerator School

Science.gov Websites

U.S. Particle Accelerator School U.S. Particle Accelerator School U.S. Particle Accelerator School U.S. Particle Accelerator School Education in Beam Physics and Accelerator Technology Home About About University Credits Joint International Accelerator School University-Style Programs Symposium-Style Programs

Research status and future trends on surface pre-grouting technology in reforming wall rock of vertical shafts in coal mines in China

NASA Astrophysics Data System (ADS)

Wang, Hua

2018-02-01

In the mine construction, the surface pre-grouting technology is an important method to prevent water blast in excavation process of vertical shaft when the shaft must pass through the thick, water-rich and high water-pressure bedrock aquifer. It has been nearly 60 years since the technology was used to reform wall rock of vertical shaft in coal mine in China for the first time, and the existing technology can basically meet the needs of constructing 1000m deep vertical shaft. Firstly, the article introduces that in view of Magg’s spherical seepage theory and Karol’s spherical seepage theory, Chinese scholars found that the diffusion of grout from borehole into the surrounding strata in horizontal direction is irregular through a lot of research and engineering practice of using the surface pre-grouting technology to reform wall rock of vertical shafts, and put forward the selecting principles of grout’s effective diffusion radius in one grouting engineering; Secondly, according to the shape of the grouting boreholes, surface pre-grouting technology of vertical shaft is divided into two stages: vertical borehole stage and S-type borehole stage. Thirdly, the development status of grouting materials and grouting equipment for the technology is introduced. Fourthly, grouting mode, stage height and pressure of the technology are introduced. Finally, it points out that with the increasing depth of coal mining in China, the technology of reforming wall rock of 1000~2000m deep vertical shafts will face many problems, such as grouting theory, grouting equipment, grouting finishing standard, testing and evaluation of grouting effect, and so on. And it put forward a preliminary approach to solving these problems. This paper points out future research directions of the surface pre-grouting technology in China.

High spatial resolution measurements in a single stage ram accelerator

NASA Technical Reports Server (NTRS)

Hinkey, J. B.; Burnham, E. A.; Bruckner, A. P.

1992-01-01

High spatial resolution experimental tube wall pressure measurements of ram accelerator gas dynamic phenomena are presented in this paper. The ram accelerator is a ramjet-in-tube device which operates in a manner similar to that of a conventional ramjet. The projectile resembles the centerbody of a ramjet and travels supersonically through a tube filled with a combustible gaseous mixture, with the tube acting as the outer cowling. Pressure data are recorded as the projectile passes by sensors mounted in the tube wall at various locations along the tube. Utilization of special highly instrumented sections of tube has allowed the recording of gas dynamic phenomena with high resolution. High spatial resolution tube wall pressure data from the three regimes of propulsion studied to date (subdetonative, transdetonative, and superdetonative) in a single stage gas mixture are presented and reveal the three-dimensional character of the flow field induced by projectile fins and the canting of the fins and the canting of the projectile body relative to the tube wall. Also presented for comparison to the experimental data are calculations made with an inviscid, three-dimensional CFD code. The knowledge gained from these experiments and simulations is useful in understanding the underlying nature of ram accelerator propulsive regimes, as well as assisting in the validation of three-dimensional CFD coded which model unsteady, chemically reactive flows.

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.

Accelerators for America's Future

NASA Astrophysics Data System (ADS)

Bai, Mei

2016-03-01

Particle accelerator, a powerful tool to energize beams of charged particles to a desired speed and energy, has been the working horse for investigating the fundamental structure of matter and fundermental laws of nature. Most known examples are the 2-mile long Stanford Linear Accelerator at SLAC, the high energy proton and anti-proton collider Tevatron at FermiLab, and Large Hadron Collider that is currently under operation at CERN. During the less than a century development of accelerator science and technology that led to a dazzling list of discoveries, particle accelerators have also found various applications beyond particle and nuclear physics research, and become an indispensible part of the economy. Today, one can find a particle accelerator at almost every corner of our lives, ranging from the x-ray machine at the airport security to radiation diagnostic and therapy in hospitals. This presentation will give a brief introduction of the applications of this powerful tool in fundermental research as well as in industry. Challenges in accelerator science and technology will also be briefly presented

Distribution of the background gas in the MITICA accelerator

NASA Astrophysics Data System (ADS)

Sartori, E.; Dal Bello, S.; Serianni, G.; Sonato, P.

2013-02-01

MITICA is the ITER neutral beam test facility to be built in Padova for the generation of a 40A D- ion beam with a 16×5×16 array of 1280 beamlets accelerated to 1MV. The background gas pressure distribution and the particle flows inside MITICA accelerator are critical aspects for stripping losses, generation of secondary particles and beam non-uniformities. To keep the stripping losses in the extraction and acceleration stages reasonably low, the source pressure should be 0.3 Pa or less. The gas flow in MITICA accelerator is being studied using a 3D Finite Element code, named Avocado. The gas-wall interaction model is based on the cosine law, and the whole vacuum system geometry is represented by a view factor matrix based on surface discretization and gas property definitions. Pressure distribution and mutual fluxes are then solved linearly. In this paper the result of a numerical simulation is presented, showing the steady-state pressure distribution inside the accelerator when gas enters the system at room temperature. The accelerator model is limited to a horizontal slice 400 mm high (1/4 of the accelerator height). The pressure profile at solid walls and through the beamlet axis is obtained, allowing the evaluation and the discussion of the background gas distribution and nonuniformity. The particle flux at the inlet and outlet boundaries (namely the grounded grid apertures and the lateral conductances respectively) will be discussed.

The utilization of brick walls for resisting earthquake in building technology

NASA Astrophysics Data System (ADS)

Tarigan, J.; Benedicta, C.

2018-03-01

Many structures in Indonesia use reinforced concrete frames with brick walls as their infill. Commonly, the engineers consider brick walls as the partitions and count them as the non-structural elements in the structure design. However, brick walls are capable of resisting earthquake by yielding high stiffness to the structure in case the brick walls are integrated well with the frames. It will reduce the non-structural destructions that happen to structures which is one of the most frequently impacts in the earthquake. This paper will take the effects of applying brick walls as the structural elements up by comparing it with the structure using brick walls as the partitions. The modeling of the brick walls uses the equivalent spectrum method meanwhile the seismic analysis uses the respon spectrum method. The utilization of brick walls can cause the decrement of the natural period to 42%. It also reduce the structure displacements to 53% in X-direction and 67% in Y-direction and the story drifts to 57% in X-direction and 71% in Y-direction. Otherwise, it causes the increment of the base shear only up to 3% in X-direction and 7% in Y-direction.

Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

ScienceCinema

Seryi, Andrei

2017-12-22

Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

On thick domain walls in general relativity

NASA Technical Reports Server (NTRS)

Goetz, Guenter; Noetzold, Dirk

1989-01-01

Planar scalar field configurations in general relativity differ considerably from those in flat space. It is shown that static domain walls of finite thickness in curved space-time do not possess a reflection symmetry. At infinity, the space-time tends to the Taub vacuum on one side of the wall and to the Minkowski vacuum (Rindler space-time) on the other. Massive test particles are always accelerated towards the Minkowski side, i.e., domain walls are attractive on the Taub side, but repulsive on the Minkowski side (Taub-vacuum cleaner). It is also proved that the pressure in all directions is always negative. Finally, a brief comment is made concerning the possibility of infinite, i.e., bigger than horizon size, domain walls in our universe. All of the results are independent of the form of the potential V(phi) greater than or equal to 0 of the scalar field phi.

Sustainable wall construction and exterior insulation retrofit technology process and structure

DOEpatents

Vohra, Arun

2000-01-01

A low-cost process for exterior wall insulation retrofit, or new wall construction by stacking layers of fabric tube filled with insulating material against a wall and covering them with mesh and stucco provides a durable structure with good insulating value.

Twin-Screw Extruder and Pellet Accelerator Integration Developments for ITER

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

Meitner, Steven J; Baylor, Larry R; Combs, Stephen Kirk

The ITER pellet injection system consisting of a twinscrew frozen hydrogen isotope extruder, coupled to a combination solenoid actuated pellet cutter and pneumatic pellet accelerator, is under development at the Oak Ridge National Laboratory. A prototype extruder has been built to produce a continuous solid deuterium extrusion and will be integrated with a secondary section, where pellets are cut, chambered, and launched with a single-stage pneumatic accelerator into the plasma through a guide tube. This integrated pellet injection system is designed to provide 5 mm fueling pellets, injected at a rate up to 10 Hz, or 3 mm edge localizedmore » mode (ELM) triggering pellets, injected at higher rates up to 20 Hz. The pellet cutter, chamber mechanism, and the solenoid operated pneumatic valve for the accelerator are optimized to provide pellet velocities between 200-300 m/s to ensure high pellet survivability while traversing the inner wall fueling guide tubes, and outer wall ELMpacing guide tubes. This paper outlines the current twin-screwextruder design, pellet accelerator design, and the integrationrequired for both fueling and ELM pacing pellets.« less

Fabrication Technologies of the High Gradient Accelerator Structures at 100MV/M Range

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

Wang, Juwen; /SLAC; Lewandowski, James

A CERN-SLAC-KEK collaboration on high gradient X-band structure research has been established in order to demonstrate the feasibility of the CLIC baseline design for the main linac stably operating at more than 100 MV/m loaded accelerating gradient. Several prototype CLIC structures were successfully fabricated and high power tested. They operated at 105 MV/m with a breakdown rate that meets the CLIC linear collider specifications of < 5 x 10{sup -7}/pulse/m. This paper summarizes the fabrication technologies including the mechanical design, precision machining, chemical cleaning, diffusion bonding as well as vacuum baking and all related assembly technologies. Also, the tolerances control,more » tuning and RF characterization will be discussed.« less

Evaluating activation of the shielding walls of a treatment room using the Monte Carlo method

NASA Astrophysics Data System (ADS)

Lee, D.-Y.; Kim, J.-H.

2018-05-01

This study investigates the radiation activation process in a medical linear accelerator, which creates a photon beam with the energy acquired from accelerated electrons. The concrete shielding walls used in conjunction with a medical linear accelerator occupy the largest portion of facility decommissioning costs. Therefore, to evaluate the activation of the shielding wall, this study simulated the operation of a linear accelerator with high-energy photon beams (10, 15, and 20 MV). The results of the simulations showed that the high-energy photon beams produced a large number of neutrons in the areas around the linear accelerator head. Several radionuclides were identified, and their half-lives and radioactivity levels were calculated. Half-lives ranged from 2.62 hours to 3.68E+06 years, and the radioactivity levels of most of the radionuclides were found to satisfy their respective clearance requirements. These results indicate that photon beams of 15 MV or lower satisfy the clearance requirements for decommissioning a linear accelerator facility, whereas those of 20 MV or higher lie partially above the regulatory clearance levels.

Accelerator Science: Why RF?

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

Lincoln, Don

Particle accelerators can fire beams of subatomic particles at near the speed of light. The accelerating force is generated using radio frequency technology and a whole lot of interesting features. In this video, Fermilab’s Dr. Don Lincoln explains how it all works.

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

Area- and energy-efficient CORDIC accelerators in deep sub-micron CMOS technologies

NASA Astrophysics Data System (ADS)

Vishnoi, U.; Noll, T. G.

2012-09-01

The COordinate Rotate DIgital Computer (CORDIC) algorithm is a well known versatile approach and is widely applied in today's SoCs for especially but not restricted to digital communications. Dedicated CORDIC blocks can be implemented in deep sub-micron CMOS technologies at very low area and energy costs and are attractive to be used as hardware accelerators for Application Specific Instruction Processors (ASIPs). Thereby, overcoming the well known energy vs. flexibility conflict. Optimizing Global Navigation Satellite System (GNSS) receivers to reduce the hardware complexity is an important research topic at present. In such receivers CORDIC accelerators can be used for digital baseband processing (fixed-point) and in Position-Velocity-Time estimation (floating-point). A micro architecture well suited to such applications is presented. This architecture is parameterized according to the wordlengths as well as the number of iterations and can be easily extended for floating point data format. Moreover, area can be traded for throughput by partially or even fully unrolling the iterations, whereby the degree of pipelining is organized with one CORDIC iteration per cycle. From the architectural description, the macro layout can be generated fully automatically using an in-house datapath generator tool. Since the adders and shifters play an important role in optimizing the CORDIC block, they must be carefully optimized for high area and energy efficiency in the underlying technology. So, for this purpose carry-select adders and logarithmic shifters have been chosen. Device dimensioning was automatically optimized with respect to dynamic and static power, area and performance using the in-house tool. The fully sequential CORDIC block for fixed-point digital baseband processing features a wordlength of 16 bits, requires 5232 transistors, which is implemented in a 40-nm CMOS technology and occupies a silicon area of 1560 μm2 only. Maximum clock frequency from circuit

Investigations into dual-grating THz-driven accelerators

NASA Astrophysics Data System (ADS)

Wei, Y.; Ischebeck, R.; Dehler, M.; Ferrari, E.; Hiller, N.; Jamison, S.; Xia, G.; Hanahoe, K.; Li, Y.; Smith, J. D. A.; Welsch, C. P.

2018-01-01

Advanced acceleration technologies are receiving considerable interest in order to miniaturize future particle accelerators. One such technology is the dual-grating dielectric structures, which can support accelerating fields one to two orders of magnitude higher than the metal RF cavities in conventional accelerators. This opens up the possibility of enabling high accelerating gradients of up to several GV/m. This paper investigates numerically a quartz dual-grating structure which is driven by THz pulses to accelerate electrons. Geometry optimizations are carried out to achieve the trade-offs between accelerating gradient and vacuum channel gap. A realistic electron bunch available from the future Compact Linear Accelerator for Research and Applications (CLARA) is loaded into an optimized 100-period dual-grating structure for a detailed wakefield study. A THz pulse is then employed to interact with this CLARA bunch in the optimized structure. The computed beam quality is analyzed in terms of emittance, energy spread and loaded accelerating gradient. The simulations show that an accelerating gradient of 348 ± 12 MV/m with an emittance growth of 3.0% can be obtained.

Proposal for an Accelerator R&D User Facility at Fermilab's Advanced Superconducting Test Accelerator (ASTA)

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

Church, M.; Edwards, H.; Harms, E.

2013-10-01

Fermilab is the nation’s particle physics laboratory, supported by the DOE Office of High Energy Physics (OHEP). Fermilab is a world leader in accelerators, with a demonstrated track-record— spanning four decades—of excellence in accelerator science and technology. We describe the significant opportunity to complete, in a highly leveraged manner, a unique accelerator research facility that supports the broad strategic goals in accelerator science and technology within the OHEP. While the US accelerator-based HEP program is oriented toward the Intensity Frontier, which requires modern superconducting linear accelerators and advanced highintensity storage rings, there are no accelerator test facilities that support themore » accelerator science of the Intensity Frontier. Further, nearly all proposed future accelerators for Discovery Science will rely on superconducting radiofrequency (SRF) acceleration, yet there are no dedicated test facilities to study SRF capabilities for beam acceleration and manipulation in prototypic conditions. Finally, there are a wide range of experiments and research programs beyond particle physics that require the unique beam parameters that will only be available at Fermilab’s Advanced Superconducting Test Accelerator (ASTA). To address these needs we submit this proposal for an Accelerator R&D User Facility at ASTA. The ASTA program is based on the capability provided by an SRF linac (which provides electron beams from 50 MeV to nearly 1 GeV) and a small storage ring (with the ability to store either electrons or protons) to enable a broad range of beam-based experiments to study fundamental limitations to beam intensity and to develop transformative approaches to particle-beam generation, acceleration and manipulation which cannot be done elsewhere. It will also establish a unique resource for R&D towards Energy Frontier facilities and a test-bed for SRF accelerators and high brightness beam applications in support of the

Particle acceleration on a chip: A laser-driven micro-accelerator for research and industry

NASA Astrophysics Data System (ADS)

Yoder, R. B.; Travish, G.

2013-03-01

Particle accelerators are conventionally built from radio-frequency metal cavities, but this technology limits the maximum energy available and prevents miniaturization. In the past decade, laser-powered acceleration has been intensively studied as an alternative technology promising much higher accelerating fields in a smaller footprint and taking advantage of recent advances in photonics. Among the more promising approaches are those based on dielectric field-shaping structures. These ``dielectric laser accelerators'' (DLAs) scale with the laser wavelength employed and can be many orders of magnitude smaller than conventional accelerators; DLAs may enable the production of high-intensity, ultra-short relativistic electron bunches in a chip-scale device. When combined with a high- Z target or an optical-period undulator, these systems could produce high-brilliance x-rays from a breadbox-sized device having multiple applications in imaging, medicine, and homeland security. In our research program we have developed one such DLA, the Micro-Accelerator Platform (MAP). We describe the fundamental physics, our fabrication and testing program, and experimental results to date, along with future prospects for MAP-based light-sources and some remaining challenges. Supported in part by the Defense Threat Reduction Agency and National Nuclear Security Administration.

Effects of reactive oxygen species on cellular wall disassembly of banana fruit during ripening.

PubMed

Cheng, Guiping; Duan, Xuewu; Shi, John; Lu, Wangjin; Luo, Yunbo; Jiang, Weibo; Jiang, Yueming

2008-07-15

Fruit softening is generally attributed to cell wall disassembly. Experiments were conducted to investigate effects of various reactive oxygen species (ROS) on in vitro cellular wall disassembly of harvested banana fruit. The alcohol-extracted insoluble residue (AEIR) was obtained from the pulp tissues of banana fruit at various ripening stages and then used to examine the disassembly of cellular wall polysaccharides in the presence of superoxide anion (O2(-)), hydrogen peroxide (H2O2) or hydroxyl radical (OH) and their scavengers. The presence of OH accelerated significantly disassembly of cellular wall polysaccharides in terms of the increase in contents of total sugars released and uronic acid, and the decrease in molecular mass of soluble polysaccharides, using gel permeation chromatography. However, the treatment with H2O2 or O2(-) showed no significant effect on the disassembly of cellular wall polysaccharides. Furthermore, the degradation of the de-esterified AEIR was more susceptible to OH attack than the esterified AEIR. In addition, the effect of OH could be inhibited in the presence of OH scavenger. This study suggests that disassembly of cellular wall polysaccharides could be initiated by OH as the solublisation of the polysaccharides increased, which, in turn, accelerated fruit softening. Copyright © 2008 Elsevier Ltd. All rights reserved.

Green Walls as an Approach in Grey Water Treatment

NASA Astrophysics Data System (ADS)

Rysulova, Martina; Kaposztasova, Daniela; Vranayova, Zuzana

2017-10-01

Grey water contributes significantly to waste water parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total phosphorus (Ptotal), total nitrogen (Ntotal), ammonium, boron, metals, salts, surfactants, synthetic chemicals, oils and greases, xenobiotic substances and microorganisms. Concentration of these pollutants and the water quality highlights the importance of treatment process in grey water systems. Treatment technologies operating under low energy and maintenance are usually preferred, since they are more cost effective for users. Treatment technologies based on natural processes represent an example of such technology including vegetated wall. Main aim of this paper is to introduce the proposal of vegetated wall managing grey water and brief characteristic of proposed system. Is expected that prepared experiment will establish the purifying ability and the potential of green wall application as an efficient treatment technology.

Control of supersonic wind-tunnel noise by laminarization of nozzle-wall boundary layer

NASA Technical Reports Server (NTRS)

Beckwith, I. E.; Harvey, W. D.; Harris, J. E.; Holley, B. B.

1973-01-01

One of the principal design requirements for a quiet supersonic or hypersonic wind tunnel is to maintain laminar boundary layers on the nozzle walls and thereby reduce disturbance levels in the test flow. The conditions and apparent reasons for laminar boundary layers which have been observed during previous investigations on the walls of several nozzles for exit Mach numbers from 2 to 20 are reviewed. Based on these results, an analysis and an assessment of nozzle design requirements for laminar boundary layers including low Reynolds numbers, high acceleration, suction slots, wall temperature control, wall roughness, and area suction are presented.

FLOW SEPARATION CONDITIONS AT PIPE WALLS OF WATER DISTRIBUTION MAINS

EPA Science Inventory

Biofilm formations on pipe walls have been found in potable water distribution mains. The biofilm layers contribute to accelerated corrosion rates, increased flow resistance, and formation of encrustations that may deteriorate drinking water quality. Research to evaluate the depe...

Enhanced cold wall CVD reactor growth of horizontally aligned single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Mu, Wei; Kwak, Eun-Hye; Chen, Bingan; Huang, Shirong; Edwards, Michael; Fu, Yifeng; Jeppson, Kjell; Teo, Kenneth; Jeong, Goo-Hwan; Liu, Johan

2016-05-01

HASynthesis of horizontally-aligned single-walled carbon nanotubes (HA-SWCNTs) by chemical vapor deposition (CVD) directly on quartz seems very promising for the fabrication of future nanoelectronic devices. In comparison to hot-wall CVD, synthesis of HA-SWCNTs in a cold-wall CVD chamber not only means shorter heating, cooling and growth periods, but also prevents contamination of the chamber. However, since most synthesis of HA-SWCNTs is performed in hot-wall reactors, adapting this well-established process to a cold-wall chamber becomes extremely crucial. Here, in order to transfer the CVD growth technology from a hot-wall to a cold-wall chamber, a systematic investigation has been conducted to determine the influence of process parameters on the HA-SWCNT's growth. For two reasons, the cold-wall CVD chamber was upgraded with a top heater to complement the bottom substrate heater; the first reason to maintain a more uniform temperature profile during HA-SWCNTs growth, and the second reason to preheat the precursor gas flow before projecting it onto the catalyst. Our results show that the addition of a top heater had a significant effect on the synthesis. Characterization of the CNTs shows that the average density of HA-SWCNTs is around 1 - 2 tubes/ μm with high growth quality as shown by Raman analysis. [Figure not available: see fulltext.

Radiotherapy using a laser proton accelerator

NASA Astrophysics Data System (ADS)

Murakami, Masao; Hishikawa, Yoshio; Miyajima, Satoshi; Okazaki, Yoshiko; Sutherland, Kenneth L.; Abe, Mitsuyuki; Bulanov, Sergei V.; Daido, Hiroyuki; Esirkepov, Timur Zh.; Koga, James; Yamagiwa, Mitsuru; Tajima, Toshiki

2008-06-01

Laser acceleration promises innovation in particle beam therapy of cancer where an ultra-compact accelerator system for cancer beam therapy can become affordable to a broad range of patients. This is not feasible without the introduction of a technology that is radically different from the conventional accelerator-based approach. Because of its compactness and other novel characteristics, the laser acceleration method provides many enhanced capabilities

Pulsating Flows in a Tube with Expandable Wall

NASA Astrophysics Data System (ADS)

Raguso, Frank; Goushcha, Oleg

2017-11-01

A mean axial fluid flow inside a cardiovascular system has a periodic behavior driven by a heart. In one period, the flow through aorta is accelerated to a Reynolds number associated with turbulent flow and decelerated to nearly stagnant condition. The cyclic pressure in the aorta also exerts time-dependent forces on the walls of the cardiovascular system. Since walls are not rigid, they can expand under fluidic pressure. It is of interest to examine the effect of expandable walls on the flow regime transition. To achieve this, an experimental apparatus has been set up. The periodic mean axial flow inside the tubes is driven by a motor-controlled piston programmed to induce a periodic flow. A time-resolved particle image velocimetry method has been used to calculate the flow velocity field in two tubes: (1) a rigid tube and (2) a flexible tube with expandable walls. The velocity fields from two tubes were comparted to identify any differences in flow transition mechanisms.

Slot-coupled CW standing wave accelerating cavity

DOEpatents

Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

2017-05-16

A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

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

Beam acceleration through proton radio frequency quadrupole accelerator in BARC

NASA Astrophysics Data System (ADS)

Bhagwat, P. V.; Krishnagopal, S.; Mathew, J. V.; Singh, S. K.; Jain, P.; Rao, S. V. L. S.; Pande, M.; Kumar, R.; Roychowdhury, P.; Kelwani, H.; Rama Rao, B. V.; Gupta, S. K.; Agarwal, A.; Kukreti, B. M.; Singh, P.

2016-05-01

A 3 MeV proton Radio Frequency Quadrupole (RFQ) accelerator has been designed at the Bhabha Atomic Research Centre, Mumbai, India, for the Low Energy High Intensity Proton Accelerator (LEHIPA) programme. The 352 MHz RFQ is built in 4 segments and in the first phase two segments of the LEHIPA RFQ were commissioned, accelerating a 50 keV, 1 mA pulsed proton beam from the ion source, to an energy of 1.24 MeV. The successful operation of the RFQ gave confidence in the physics understanding and technology development that have been achieved, and indicate that the road forward can now be traversed rather more quickly.

Technology Solutions Case Study: Hygrothermal Performance of a Double-Stud Cellulose Wall

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

None

2015-06-01

Moisture problems within the building shell can be caused by a number of factors including excess interior moisture that is transported into the wall through air leakage and vapor drive, bulk water intrusion from leaks and wind-driven rain, capillary action from concrete to wood connections, and through wetted building materials such as siding wetted from rain splash back. With the increasing thickness of walls, moisture issues could increase. Several builders have successfully used “double-wall” systems to more practically achieve higher R-values in thicker framed walls. A double wall typically consists of a load-bearing external frame wall constructed with 2 ×more » 4 framing at 16 in. on center using conventional methods. After the building is enclosed, an additional frame wall is constructed several inches inside the load-bearing wall. Several researchers have used moisture modeling software to conduct extensive analysis of these assemblies; however, little field research has been conducted to validate the results. In this project, the Building America research team Consortium for Advanced Residential Buildings monitored a double-stud assembly in climate zone 5A to determine the accu¬racy of moisture modeling and make recommendations to ensure durable and efficient assemblies.« less

Use of flexible facing for soil nail walls.

DOT National Transportation Integrated Search

2011-11-01

Soil nail walls are a widely used technology for retaining vertical and nearly vertical cuts in soil. A : significant portion of the cost of soil nail wall construction is related to the construction of a reinforced : concrete face. The potential for...

Access to Data Accelerates Innovation and Adoption of Geothermal

Science.gov Websites

Technologies | News | NREL Access to Data Accelerates Innovation and Adoption of Geothermal Technologies Access to Data Accelerates Innovation and Adoption of Geothermal Technologies May 18, 2018 A map of the continental U.S. is overlaid with a colored map showing deep geothermal heat potential. NREL's

Accelerator science in medical physics.

PubMed

Peach, K; Wilson, P; Jones, B

2011-12-01

The use of cyclotrons and synchrotrons to accelerate charged particles in hospital settings for the purpose of cancer therapy is increasing. Consequently, there is a growing demand from medical physicists, radiographers, physicians and oncologists for articles that explain the basic physical concepts of these technologies. There are unique advantages and disadvantages to all methods of acceleration. Several promising alternative methods of accelerating particles also have to be considered since they will become increasingly available with time; however, there are still many technical problems with these that require solving. This article serves as an introduction to this complex area of physics, and will be of benefit to those engaged in cancer therapy, or who intend to acquire such technologies in the future.

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

A preliminary design of the collinear dielectric wakefield accelerator

NASA Astrophysics Data System (ADS)

Zholents, A.; Gai, W.; Doran, S.; Lindberg, R.; Power, J. G.; Strelnikov, N.; Sun, Y.; Trakhtenberg, E.; Vasserman, I.; Jing, C.; Kanareykin, A.; Li, Y.; Gao, Q.; Shchegolkov, D. Y.; Simakov, E. I.

2016-09-01

A preliminary design of the multi-meter long collinear dielectric wakefield accelerator that achieves a highly efficient transfer of the drive bunch energy to the wakefields and to the witness bunch is considered. It is made from 0.5 m long accelerator modules containing a vacuum chamber with dielectric-lined walls, a quadrupole wiggler, an rf coupler, and BPM assembly. The single bunch breakup instability is a major limiting factor for accelerator efficiency, and the BNS damping is applied to obtain the stable multi-meter long propagation of a drive bunch. Numerical simulations using a 6D particle tracking computer code are performed and tolerances to various errors are defined.

Possibility for ultra-bright electron beam acceleration in dielectric wakefield accelerators

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

Simakov, Evgenya I.; Carlsten, Bruce E.; Shchegolkov, Dmitry Yu.

2012-12-21

We describe a conceptual proposal to combine the Dielectric Wakefield Accelerator (DWA) with the Emittance Exchanger (EEX) to demonstrate a high-brightness DWA with a gradient of above 100 MV/m and less than 0.1% induced energy spread in the accelerated beam. We currently evaluate the DWA concept as a performance upgrade for the future LANL signature facility MaRIE with the goal of significantly reducing the electron beam energy spread. The preconceptual design for MaRIE is underway at LANL, with the design of the electron linear accelerator being one of the main research goals. Although generally the baseline design needs to bemore » conservative and rely on existing technology, any future upgrade would immediately call for looking into the advanced accelerator concepts capable of boosting the electron beam energy up by a few GeV in a very short distance without degrading the beam's quality. Scoping studies have identified large induced energy spreads as the major cause of beam quality degradation in high-gradient advanced accelerators for free-electron lasers. We describe simulations demonstrating that trapezoidal bunch shapes can be used in a DWA to greatly reduce the induced beam energy spread, and, in doing so, also preserve the beam brightness at levels never previously achieved. This concept has the potential to advance DWA technology to a level that would make it suitable for the upgrades of the proposed Los Alamos MaRIE signature facility.« less

Advances in the genetic dissection of plant cell walls: tools and resources available in Miscanthus

PubMed Central

Slavov, Gancho; Allison, Gordon; Bosch, Maurice

2013-01-01

Tropical C4 grasses from the genus Miscanthus are believed to have great potential as biomass crops. However, Miscanthus species are essentially undomesticated, and genetic, molecular and bioinformatics tools are in very early stages of development. Furthermore, similar to other crops targeted as lignocellulosic feedstocks, the efficient utilization of biomass is hampered by our limited knowledge of the structural organization of the plant cell wall and the underlying genetic components that control this organization. The Institute of Biological, Environmental and Rural Sciences (IBERS) has assembled an extensive collection of germplasm for several species of Miscanthus. In addition, an integrated, multidisciplinary research programme at IBERS aims to inform accelerated breeding for biomass productivity and composition, while also generating fundamental knowledge. Here we review recent advances with respect to the genetic characterization of the cell wall in Miscanthus. First, we present a summary of recent and on-going biochemical studies, including prospects and limitations for the development of powerful phenotyping approaches. Second, we review current knowledge about genetic variation for cell wall characteristics of Miscanthus and illustrate how phenotypic data, combined with high-density arrays of single-nucleotide polymorphisms, are being used in genome-wide association studies to generate testable hypotheses and guide biological discovery. Finally, we provide an overview of the current knowledge about the molecular biology of cell wall biosynthesis in Miscanthus and closely related grasses, discuss the key conceptual and technological bottlenecks, and outline the short-term prospects for progress in this field. PMID:23847628

Computer simulations of Hall thrusters without wall losses designed using two permanent magnetic rings

NASA Astrophysics Data System (ADS)

Yongjie, Ding; Wuji, Peng; Liqiu, Wei; Guoshun, Sun; Hong, Li; Daren, Yu

2016-11-01

A type of Hall thruster without wall losses is designed by adding two permanent magnet rings in the magnetic circuit. The maximum strength of the magnetic field is set outside the channel. Discharge without wall losses is achieved by pushing down the magnetic field and adjusting the channel accordingly. The feasibility of the Hall thrusters without wall losses is verified via a numerical simulation. The simulation results show that the ionization region is located in the discharge channel and the acceleration region is outside the channel, which decreases the energy and flux of ions and electrons spattering on the wall. The power deposition on the channel walls can be reduced by approximately 30 times.

Potential dangers of accelerant use in arson.

PubMed

Heath, Karen; Kobus, Hilton; Byard, Roger W

2011-02-01

Accelerant-enhanced combustion often characterizes a fire that has been deliberately set to disguise a murder scene or to destroy property for insurance purposes. The intensity and rapidity of spread of fires where accelerants have been used are often underestimated by perpetrators who may sustain heat-related injuries. The case of a 49-year-old male who was using gasoline (petrol) as an accelerant is reported to demonstrate another danger of this type of activity. After ignition, an explosion occurred that destroyed the building and caused the death of the victim who was crushed beneath a rear wall of the commercial premises. Gasoline vapour/air mixtures are extremely volatile and may cause significant explosions if exposed to flame. Given the potential danger of explosion, arsonists using accelerants do so at significant risk to themselves and to others in the vicinity. Copyright © 2011 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Accelerated Life Testing and Service Lifetime Prediction for PV Technologies in the Twenty-First Century

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

Czanderna, A. W.; Jorgensen, G. J.

The purposes of this paper are to (1) discuss the necessity for conducting accelerated life testing (ALT) in the early stages of developing new photovoltaic (PV) technologies, (2) elucidate the crucial importance for combining ALT with real-time testing (RTT) in terrestrial environments for promising PV technologies for the 21st century, and (3) outline the essential steps for making a service lifetime prediction (SLP) for any PV technology. The specific objectives are to (a) illustrate the essential need for ALT of complete, encapsulated multilayer PV devices, (b) indicate the typical causes of degradation in PV stacks, (c) elucidate the complexity associatedmore » with quantifying the durability of the devices, (d) explain the major elements that constitute a generic SLP methodology, (e) show how the introduction of the SLP methodology in the early stages of new device development can reduce the cost of technology development, and (f) outline the procedure for combining the results of ALT and RTT, establishing degradation mechanisms, using sufficient numbers of samples, and applying the SLP methodology to produce a SLP for existing or new PV technologies.« less

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.

Carbohydrate Microarray Technology Applied to High-Throughput Mapping of Plant Cell Wall Glycans Using Comprehensive Microarray Polymer Profiling (CoMPP).

PubMed

Kračun, Stjepan Krešimir; Fangel, Jonatan Ulrik; Rydahl, Maja Gro; Pedersen, Henriette Lodberg; Vidal-Melgosa, Silvia; Willats, William George Tycho

2017-01-01

Cell walls are an important feature of plant cells and a major component of the plant glycome. They have both structural and physiological functions and are critical for plant growth and development. The diversity and complexity of these structures demand advanced high-throughput techniques to answer questions about their structure, functions and roles in both fundamental and applied scientific fields. Microarray technology provides both the high-throughput and the feasibility aspects required to meet that demand. In this chapter, some of the most recent microarray-based techniques relating to plant cell walls are described together with an overview of related contemporary techniques applied to carbohydrate microarrays and their general potential in glycoscience. A detailed experimental procedure for high-throughput mapping of plant cell wall glycans using the comprehensive microarray polymer profiling (CoMPP) technique is included in the chapter and provides a good example of both the robust and high-throughput nature of microarrays as well as their applicability to plant glycomics.

Accelerated aortic imaging using small field of view imaging and electrocardiogram-triggered quadruple inversion recovery magnetization preparation.

PubMed

Peel, Sarah A; Hussain, Tarique; Cecelja, Marina; Abbas, Abeera; Greil, Gerald F; Chowienczyk, Philip; Spector, Tim; Smith, Alberto; Waltham, Matthew; Botnar, Rene M

2011-11-01

To accelerate and optimize black blood properties of the quadruple inversion recovery (QIR) technique for imaging the abdominal aortic wall. QIR inversion delays were optimized for different heart rates in simulations and phantom studies by minimizing the steady state magnetization of blood for T(1) = 100-1400 ms. To accelerate and improve black blood properties of aortic vessel wall imaging, the QIR prepulse was combined with zoom imaging and (a) "traditional" and (b) "trailing" electrocardiogram (ECG) triggering. Ten volunteers were imaged pre- and post-contrast administration using a conventional ECG-triggered double inversion recovery (DIR) and the two QIR implementations in combination with a zoom-TSE readout. The QIR implemented with "trailing" ECG-triggering resulted in consistently good blood suppression as the second inversion delay was timed during maximum systolic flow in the aorta. The blood signal-to-noise ratio and vessel wall to blood contrast-to-noise ratio, vessel wall sharpness, and image quality scores showed a statistically significant improvement compared with the traditional QIR implementation with and without ECG-triggering. We demonstrate that aortic vessel wall imaging can be accelerated with zoom imaging and that "trailing" ECG-triggering improves black blood properties of the aorta which is subject to motion and variable blood flow during the cardiac cycle. Copyright © 2011 Wiley Periodicals, Inc.

Infographic Development by Accelerated Bachelor of Science in Nursing Students: An Innovative Technology-Based Approach to Public Health Education.

PubMed

Falk, Nancy L

Health communications and baccalaureate nursing education are increasingly impacted by new technological tools. This article describes how an Accelerated Bachelor of Science in Nursing program incorporates an infographic assignment into a graduate-level online health information and technology course. Students create colorful, engaging infographics using words and visuals to communicate public health information. The assignment, which incorporates the use of data and evidence, provides students the opportunity to acquire new research and technology skills while gaining confidence creating and innovating. The finished products may be disseminated, serving as vehicles to influence public health and well-being.

Study of the Accelerating Channel Wall Property Influence on the Hall Thruster Discharge Characteristics

DTIC Science & Technology

2004-11-01

Hall thruster characteristics there was prepared Hall thruster model of the SPT-100 type for these experiments and there were manufactured the required discharge chamber parts (rings) made of the Russian BN-SiO2 (borosil) ceramics and of the Russian AIN-BN (ABN) and Western ABN ceramics having secondary electron emission yield (SEEY) different from that one for borosil. These parts were replaceable during experiments. Thruster model was equipped by set of the near wall probes mounted at external discharge chamber wall. There was made characterization

Diagnostic resonant cavity for a charged particle accelerator

DOEpatents

Barov, Nikolai

2007-10-02

Disclosed is a diagnostic resonant cavity for determining characteristics of a charged particle beam, such as an electron beam, produced in a charged particle accelerator. The cavity is based on resonant quadrupole-mode and higher order cavities. Enhanced shunt impedance in such cavities is obtained by the incorporation of a set of four or more electrically conductive rods extending inwardly from either one or both of the end walls of the cavity, so as to form capacitive gaps near the outer radius of the beam tube. For typical diagnostic cavity applications, a five-fold increase in shunt impedance can be obtained. In alternative embodiments the cavity may include either four or more opposing pairs of rods which extend coaxially toward one another from the opposite end walls of the cavity and are spaced from one another to form capacitative gaps; or the cavity may include a single set of individual rods that extend from one end wall to a point adjacent the opposing end wall.

Estimation of Metal Acceleration by an SF5 Containing Explosive

DTIC Science & Technology

1991-06-30

cylinder wall acceleration, the wall energies for the baseline composition and for the composition CW2 were calculated by three different methods : KSM, 6...computaticno! method to calculate the cylinder energies needed for comparison with expermental data, it was decided to compare data from three known methods ...detonation pressure given for the GAB method in Reference 8. They are E(6mm) = 0.1272 (Isp X density)1 .5 - 0.021, and E(l9mm) = 0.1580 (Isp x density) 1 .5

Beam trapping in high-current cyclic accelerators with strong-focusing fields. Memorandum report, January-December 1984

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

Sprangle, P.; Kapetanakos, C.A.

1985-03-06

In cyclic induction accelerators, the energy of the particles increases slowly in synchronism with the vertical (betatron) magnetic field. As a consequence of the slow acceleration, the charged particles must be confined by the weak-focusing magnetic field over long periods of time, and thus field errors, instabilities, and radiation losses can impose limitations on the acceleration process. These limitations can be substantially relaxed if the acceleration were to occur rapidly, say over a few microseconds. An appropriate name for such an accelerator is REBA-TRON (Rapid Electron Beam Accelerator). This paper considers a possible mechanism which could trap a high currentmore » electron beam in the strong focusing magnetic fields of the rebatron. We investigate a possible mechanism for trapping an intense relativistic electron beam confined by strong focusing fields. In our model the electron beam is assumed to be injected into torsatron fields off axis, near the chamber walls. The finite resistivity of the walls results in a drag force on the beam centroid which may cause the beam to spiral inward towards the axis of the chamber. We have analyzed this mechanism and obtained decay rates for the inward spiraling beam motion.« less

The limiting velocity effect in a magnetically held discharge with a moving wall

NASA Astrophysics Data System (ADS)

Drobyshevskii, E. M.; Zhukov, B. G.; Nazarov, E. V.; Rozov, S. I.; Sokolov, V. M.; Kurakin, R. O.

1991-08-01

Experiments are reported in which bodies with a mass of about 1 g were accelerated in nearly constant current regimes by using a discharge magnetically held against the channel wall, with maximum permissible accelerations of 3.5 x 10 exp 6 g and linear current densities of 60 kA/mm. A saturation of the velocity was observed at 4-6 mm/microsec. The velocity limit does not depend on the current intensity and duration or linear electrode inductance and is proportional to m exp -1/2; it is practically unaffected by the characteristics of body friction against the channel walls and by small deviations of the current pulse shape from its constant value. A simple empirical theory is proposed which provides an adequate description of the experimentally observed phenomena.

Performance of masonry enclosure walls: lessons learned from recent earthquakes

NASA Astrophysics Data System (ADS)

Vicente, Romeu Silva; Rodrigues, Hugo; Varum, Humberto; Costa, Aníbal; Mendes da Silva, José António Raimundo

2012-03-01

This paper discusses the issue of performance requirements and construction criteria for masonry enclosure and infill walls. Vertical building enclosures in European countries are very often constituted by non-load-bearing masonry walls, using horizontally perforated clay bricks. These walls are generally supported and confined by a reinforced concrete frame structure of columns and beams/slabs. Since these walls are commonly considered to be nonstructural elements and their influence on the structural response is ignored, their consideration in the design of structures as well as their connection to the adjacent structural elements is frequently negligent or insufficiently detailed. As a consequence, nonstructural elements, as for wall enclosures, are relatively sensitive to drift and acceleration demands when buildings are subjected to seismic actions. Many international standards and technical documents stress the need for design acceptability criteria for nonstructural elements, however they do not specifically indicate how to prevent collapse and severe cracking, and how to enhance the overall stability in the case of moderate to high seismic loading. Furthermore, a review of appropriate measures to improve enclosure wall performance and both in-plane and out-of-plane integrity under seismic actions is addressed.

Implementing Green Walls in Schools.

PubMed

McCullough, Michael B; Martin, Michael D; Sajady, Mollika A

2018-01-01

Numerous studies in applied pedagogical design have shown that, at all educational levels, direct exposure to the natural environment can enhance learning by improving student attention and behaviors. Implementing green walls-a "vertical garden," or "living wall" interior wall that typically includes greenery, a growing medium (soil or substrate) and a water delivery system-provides environmental health benefits, but also provides a practical application within classrooms for minimizing directed attention fatigue in students by connecting them to "outdoor nature" within the indoor environment. Hands-on "project-based" learning is another pedagogical strategy that has proved to be effective across the spectrum of educational levels and across subject areas. Green walls have the potential to inspire critical thinking through a combination of project-based learning strategies and environmental education. The authors have outlined a curriculum involving the implementation of an indoor living wall system within a classroom-learning environment, incorporating project-based learning modules that interact with the wall. In conjunction with the passive health benefits of a green wall, project-based curriculum models can connect students interactively with indoor nature and have the potential to inspire real-world thinking related to science, technology, engineering, art, and mathematics fields within the indoor learning environment. Through a combination of these passive and interactive modes, students are connected to nature in the indoor environment regardless of weather conditions outdoors. Future research direction could include post-construction studies of the effectiveness of project-based curricula related to living walls, and the long-term impacts of implementing green walls in classrooms on school achievement and student behaviors.

Simulation of Cascaded Longitudinal-Space-Charge Amplifier at the Fermilab Accelerator Science & Technology (Fast) Facility

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

Halavanau, A.; Piot, P.

2015-12-01

Cascaded Longitudinal Space Charge Amplifiers (LSCA) have been proposed as a mechanism to generate density modulation over a board spectral range. The scheme has been recently demonstrated in the optical regime and has confirmed the production of broadband optical radiation. In this paper we investigate, via numerical simulations, the performance of a cascaded LSCA beamline at the Fermilab Accelerator Science & Technology (FAST) facility to produce broadband ultraviolet radiation. Our studies are carried out using elegant with included tree-based grid-less space charge algorithm.

Coupling and decoupling of the accelerating units for pulsed synchronous linear accelerator

NASA Astrophysics Data System (ADS)

Shen, Yi; Liu, Yi; Ye, Mao; Zhang, Huang; Wang, Wei; Xia, Liansheng; Wang, Zhiwen; Yang, Chao; Shi, Jinshui; Zhang, Linwen; Deng, Jianjun

2017-12-01

A pulsed synchronous linear accelerator (PSLA), based on the solid-state pulse forming line, photoconductive semiconductor switch, and high gradient insulator technologies, is a novel linear accelerator. During the prototype PSLA commissioning, the energy gain of proton beams was found to be much lower than expected. In this paper, the degradation of the energy gain is explained by the circuit and cavity coupling effect of the accelerating units. The coupling effects of accelerating units are studied, and the circuit topologies of these two kinds of coupling effects are presented. Two methods utilizing inductance and membrane isolations, respectively, are proposed to reduce the circuit coupling effects. The effectiveness of the membrane isolation method is also supported by simulations. The decoupling efficiency of the metal drift tube is also researched. We carried out the experiments on circuit decoupling of the multiple accelerating cavity. The result shows that both circuit decoupling methods could increase the normalized voltage.

EXPERIMENTAL STUDY ON BEHAVIOR OF KENCHI BLOCK MASONRY WALL WITH THE SHAKING TABLE TEST DURING BY VIBRATION CHARACTERISTICS AND FAILURE MECHANISM

NASA Astrophysics Data System (ADS)

Ikemoto, Toshikazu; Mori, Masashi; Miyajima, Masakatsu; Hashimoto, Takao; Murata, Akira

There are many earthquake damages of kenchi block masonry wall. So, we carried out experimental studies on the collapse mechanism of kenchi block masonry wall during earthquake. From these experimental data, i.e. acceleration response magnification, displacement and soil pressure were found to destroy the central wall vibrations caused by the subsidence of the embankment.

GeoWall Experiences in K-12 Education

NASA Astrophysics Data System (ADS)

Johnson, A. E.

2003-12-01

Since the mid 1990s the Electronic Visualization Laboratory at the University of Illinois at Chicago has been investigating how advanced visualization technology such as CAVEs, ImmersaDesks, PCs, and plasma panels can be used effectively in K-12 education. The creation of the GeoWall has given us more flexibility in deploying these technologies, and conducting these investigations outside the laboratory. Over the two years we have been using GeoWalls in a variety of educational settings around the Chicago area. Since the Fall of 2002, the SciTech Museum in Aurora, IL has used a GeoWall to show a variety of educational content. In February 2002 the Museum of Science and Industry in Chicago, IL set up a GeoWall to show 'Virtual Harlem' which allowed museum patrons to walk the streets of Harlem NY in the 1930s to learn about the place and the people. Since 1999 we have been working with Abraham Lincoln Elementary School in Oak Park, IL using a variety of display devices to teach the scientific method and investigate the use of multiple perspectives in learning. We began using a GeoWall there in the spring of 2002 and in the spring of 2003 we expanded our work in Oak Park to include Gwendolyn Brooks Middle School.

3-D simulation of hanging wall effect at dam site

NASA Astrophysics Data System (ADS)

Zhang, L.; Xu, Y.

2017-12-01

Hanging wall effect is one of the near fault effects. This paper focuses on the difference of the ground motions on the hanging wall side between the footwall side of the fault at dam site considering the key factors, such as actual topography, the rupture process. For this purpose, 3-D ground motions are numerically simulated by the spectrum element method (SEM), which takes into account the physical mechanism of generation and propagation of seismic waves. With the SEM model of 548 million DOFs, excitation and propagation of seismic waves are simulated to compare the difference between the ground motion on the hanging wall side and that on the footwall side. Take Dagangshan region located in China as an example, several seismogenic finite faults with different dip angle are simulated to investigate the hanging wall effect. Furthermore, by comparing the ground motions of the receiving points, the influence of several factors on hanging wall effect is investigated, such as the dip of the fault and the fault type (strike slip fault or dip-slip fault). The peak acceleration on the hanging wall side is obviously larger than those on the footwall side, which numerically evidences the hanging wall effect. Besides, the simulation shows that only when the dip is less than 70° does the hanging wall effect deserve attention.

Single-walled carbon nanotubes as near-infrared optical biosensors for life sciences and biomedicine.

PubMed

Jain, Astha; Homayoun, Aida; Bannister, Christopher W; Yum, Kyungsuk

2015-03-01

Single-walled carbon nanotubes that emit photostable near-infrared fluorescence have emerged as near-infrared optical biosensors for life sciences and biomedicine. Since the discovery of their near-infrared fluorescence, researchers have engineered single-walled carbon nanotubes to function as an optical biosensor that selectively modulates its fluorescence upon binding of target molecules. Here we review the recent advances in the single-walled carbon nanotube-based optical sensing technology for life sciences and biomedicine. We discuss the structure and optical properties of single-walled carbon nanotubes, the mechanisms for molecular recognition and signal transduction in single-walled carbon nanotube complexes, and the recent development of various single-walled carbon nanotube-based optical biosensors. We also discuss the opportunities and challenges to translate this emerging technology into biomedical research and clinical use, including the biological safety of single-walled carbon nanotubes. The advances in single-walled carbon nanotube-based near-infrared optical sensing technology open up a new avenue for in vitro and in vivo biosensing with high sensitivity and high spatial resolution, beneficial for many areas of life sciences and biomedicine. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Klynac: Compact Linear Accelerator with Integrated Power Supply

NASA Astrophysics Data System (ADS)

Malyzhenkov, A. V.

Accelerators and accelerator-based light sources have a wide range of applications in science, engineering technology and medicine. Today the scientific community is working towards improving the quality of the accelerated beam and its parameters, while trying to develop technology for reducing accelerator size. This work describes a design of a compact linear accelerator (linac) prototype: resonant Klynac device, which is a combined linear accelerator and its power supply - klystron. The intended purpose of a Klynac device is to provide a compact and inexpensive alternative to a conventional 1 to 6 MeV accelerator, which typically requires a separate RF source, accelerator itself and all the associated hardware. Because the Klynac is a single structure, it has the potential to be much less sensitive to temperature variations than a system with separate klystron and linac. We start by introducing a simplified theoretical model for a Klynac device. We then demonstrate how a prototype is designed step-by-step using Particle-In-Cell simulation studies for mono-resonant and bi-resonant structures. Finally, we discuss design options from a stability point of view and required input power as well as behavior of competing modes for the actual built device.

Environmental Remediation and Conversion of Carbon Dioxide (CO2) into Useful Green Products by Accelerated Carbonation Technology

PubMed Central

Lim, Mihee; Han, Gi-Chun; Ahn, Ji-Whan; You, Kwang-Suk

2010-01-01

This paper reviews the application of carbonation technology to the environmental industry as a way of reducing carbon dioxide (CO2), a green house gas, including the presentation of related projects of our research group. An alternative technology to very slow natural carbonation is the co-called ‘accelerated carbonation’, which completes its fast reaction within few hours by using pure CO2. Carbonation technology is widely applied to solidify or stabilize solid combustion residues from municipal solid wastes, paper mill wastes, etc. and contaminated soils, and to manufacture precipitated calcium carbonate (PCC). Carbonated products can be utilized as aggregates in the concrete industry and as alkaline fillers in the paper (or recycled paper) making industry. The quantity of captured CO2 in carbonated products can be evaluated by measuring mass loss of heated samples by thermo-gravimetric (TG) analysis. The industrial carbonation technology could contribute to both reduction of CO2 emissions and environmental remediation. PMID:20195442

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.

Frontier applications of electrostatic accelerators

NASA Astrophysics Data System (ADS)

Liu, Ke-Xin; Wang, Yu-Gang; Fan, Tie-Shuan; Zhang, Guo-Hui; Chen, Jia-Er

2013-10-01

Electrostatic accelerator is a powerful tool in many research fields, such as nuclear physics, radiation biology, material science, archaeology and earth sciences. Two electrostatic accelerators, one is the single stage Van de Graaff with terminal voltage of 4.5 MV and another one is the EN tandem with terminal voltage of 6 MV, were installed in 1980s and had been put into operation since the early 1990s at the Institute of Heavy Ion Physics. Many applications have been carried out since then. These two accelerators are described and summaries of the most important applications on neutron physics and technology, radiation biology and material science, as well as accelerator mass spectrometry (AMS) are presented.

Method of and apparatus for accelerating a projectile

DOEpatents

Goldstein, Yeshayahu S. A.; Tidman, Derek A.

1986-01-01

A projectile is accelerated along a confined path by supplying a pulsed high pressure, high velocity plasma jet to the rear of the projectile as the projectile traverses the path. The jet enters the confined path at a non-zero angle relative to the projectile path. The pulse is derived from a dielectric capillary tube having an interior wall from which plasma forming material is ablated in response to a discharge voltage. The projectile can be accelerated in response to the kinetic energy in the plasma jet or in response to a pressure increase of gases in the confined path resulting from the heat added to the gases by the plasma.

Nanotubes May Break Through "Chip Wall"

NASA Technical Reports Server (NTRS)

Laufenberg, Larry

2003-01-01

In 1965, just four years after the first planar integrated circuit (IC) was discovered, Cordon Moore observed that the number of transistors per integrated circuit had grown exponentially. He predicted that this would continue, and the media soon began to call his prophesy "Moore's Law" For nearly forty years, Moore's Law has been validated by the technological progress achieved in the semiconductor industry. Now, however, industry experts are warning of a "Red Brick Wall" that may soon block the continued scaling predicted by by Moore's Law. The "red bricks" in the wall are those areas of technical challenge for which no known manufacturable solution exists. One such "brick" is the challenge of finding a new material and processing technology to replace the metals used today to interconnect transistors on a chip.

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.

Photoneutron radiation field of ducts in barrier of 15 MV medical electron accelerators

NASA Astrophysics Data System (ADS)

Deng, Lei; Zhou, Ning; Chen, Yi-shui; Tu, Yu

2017-11-01

Shielding body of the high-energy medical electron accelerators is always penetrated by ducts, which would influence the shielding capability of local barrier. In order to quantitatively analyze the duct's impact on shielding of the photoneutron from 15 MV accelerators, the ambient dose equivalent rate and energy spectrum at the center of a typical duct and the external mouth of duct were calculated based on MCNP program for the first time. The results demonstrate that leakage neutrons at the external mouth of duct are mainly thermal neutron, and its dose rate is decreased with the increase of the intersection angle between duct and wall as well as the reduction of duct diameter. When a duct in a diameter no more than 30 cm penetrates the wall unidirectionally and the inclined Angle (θ) is 60°, neutron dose rate at the external mouth of duct could meet the requirements of protection. At last, according to the calculation results, some suggestions are proposed for the shielding design of ducts in walls.

KLYNAC: Compact linear accelerator with integrated power supply

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

Malyzhenkov, Alexander

Accelerators and accelerator-based light sources have a wide range of applications in science, engineering technology and medicine. Today the scienti c community is working towards improving the quality of the accelerated beam and its parameters while trying to develop technology for reducing accelerator size. This work describes a design of a compact linear accelerator (linac) prototype, resonant Klynac device, which is a combined linear accelerator and its power supply - klystron. The intended purpose of a Klynac device is to provide a compact and inexpensive alternative to a conventional 1 to 6 MeV accelerator, which typically requires a separate RFmore » source, an accelerator itself and all the associated hardware. Because the Klynac is a single structure, it has the potential to be much less sensitive to temperature variations than a system with separate klystron and linac. We start by introducing a simpli ed theoretical model for a Klynac device. We then demonstrate how a prototype is designed step-by-step using particle-in-cell simulation studies for mono- resonant and bi-resonant structures. Finally, we discuss design options from a stability point of view and required input power as well as behavior of competing modes for the actual built device.« less

Development of Manufacturing Technology to Accelerate Cost Reduction of Low Concentration and

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

Detrick, Adam

The purpose of this project was to accelerate deployment of cost-effective US-based manufacturing of Solaria’s unique c-Si module technology. This effort successfully resulted in the development of US-based manufacturing technology to support two highly-differentiated, market leading product platforms. The project was initially predicated on developing Solaria’s low-concentration PV (LCPV) module technology which at the time of the award was uniquely positioned to exceed the SunShot price goal of $0.50/Wp for standard c-Si modules. The Solaria LCPV module is a 2.5x concentrator that leverages proven, high-reliability PV module materials and low silicon cell usage into a technology package that already hadmore » the lowest direct material cost and leading Levelized Cost of Electricity (LCOE). With over 25 MW commercially deployed globally, the Solaria module was well positioned to continue to lead in PV module cost reduction. Throughout the term of the contract, market conditions changed dramatically and so to did Solaria’s product offerings to support this. However, the manufacturing technology developed for the LCPV module was successfully leveraged and optimized to support two new and different product platforms. BIPV “PowerVision” and High-efficiency “PowerXT” modules. The primary barrier to enabling high-volume PV module manufacturing in the US is the high manual labor component in certain unique aspects of our manufacturing process. The funding was used to develop unique manufacturing automation which makes the manual labor components of these key processes more efficient and increase throughput. At the core of Solaria’s product offerings are its unique and proprietary techniques for dicing and re-arranging solar cells into modules with highly-differentiated characteristics that address key gaps in the c-Si market. It is these techniques that were successfully evolved and deployed into US-based manufacturing site with SunShot funding. Today

Electric rail gun projectile acceleration to high velocity

NASA Technical Reports Server (NTRS)

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

1982-01-01

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

Emerging Technologies for the Production of Renewable Liquid Transport Fuels from Biomass Sources Enriched in Plant Cell Walls

PubMed Central

Tan, Hwei-Ting; Corbin, Kendall R.; Fincher, Geoffrey B.

2016-01-01

Plant cell walls are composed predominantly of cellulose, a range of non-cellulosic polysaccharides and lignin. The walls account for a large proportion not only of crop residues such as wheat straw and sugarcane bagasse, but also of residues of the timber industry and specialist grasses and other plants being grown specifically for biofuel production. The polysaccharide components of plant cell walls have long been recognized as an extraordinarily large source of fermentable sugars that might be used for the production of bioethanol and other renewable liquid transport fuels. Estimates place annual plant cellulose production from captured light energy in the order of hundreds of billions of tons. Lignin is synthesized in the same order of magnitude and, as a very large polymer of phenylpropanoid residues, lignin is also an abundant, high energy macromolecule. However, one of the major functions of these cell wall constituents in plants is to provide the extreme tensile and compressive strengths that enable plants to resist the forces of gravity and a broad range of other mechanical forces. Over millions of years these wall constituents have evolved under natural selection to generate extremely tough and resilient biomaterials. The rapid degradation of these tough cell wall composites to fermentable sugars is therefore a difficult task and has significantly slowed the development of a viable lignocellulose-based biofuels industry. However, good progress has been made in overcoming this so-called recalcitrance of lignocellulosic feedstocks for the biofuels industry, through modifications to the lignocellulose itself, innovative pre-treatments of the biomass, improved enzymes and the development of superior yeasts and other microorganisms for the fermentation process. Nevertheless, it has been argued that bioethanol might not be the best or only biofuel that can be generated from lignocellulosic biomass sources and that hydrocarbons with intrinsically higher energy

Strategies To Discover the Structural Components of Cyst and Oocyst Walls

PubMed Central

Bushkin, G. Guy; Chatterjee, Aparajita; Robbins, Phillips W.

2013-01-01

Cysts of Giardia lamblia and Entamoeba histolytica and oocysts of Toxoplasma gondii and Cryptosporidium parvum are the infectious and sometimes diagnostic forms of these parasites. To discover the structural components of cyst and oocyst walls, we have developed strategies based upon a few simple assumptions. Briefly, the most abundant wall proteins are identified by monoclonal antibodies or mass spectrometry. Structural components include a sugar polysaccharide (chitin for Entamoeba, β-1,3-linked glucose for Toxoplasma, and β-1,3-linked GalNAc for Giardia) and/or acid-fast lipids (Toxoplasma and Cryptosporidium). Because Entamoeba cysts and Toxoplasma oocysts are difficult to obtain, studies of walls of nonhuman pathogens (E. invadens and Eimeria, respectively) accelerate discovery. Biochemical methods to dissect fungal walls work well for cyst and oocyst walls, although the results are often unexpected. For example, echinocandins, which inhibit glucan synthases and kill fungi, arrest the development of oocyst walls and block their release into the intestinal lumen. Candida walls are coated with mannans, while Entamoeba cysts are coated in a dextran-like glucose polymer. Models for cyst and oocyst walls derive from their structural components and organization within the wall. Cyst walls are composed of chitin fibrils and lectins that bind chitin (Entamoeba) or fibrils of the β-1,3-GalNAc polymer and lectins that bind the polymer (Giardia). Oocyst walls of Toxoplasma have two distinct layers that resemble those of fungi (β-1,3-glucan in the inner layer) or mycobacteria (acid-fast lipids in the outer layer). Oocyst walls of Cryptosporidium have a rigid bilayer of acid-fast lipids and inner layer of oocyst wall proteins. PMID:24096907

Evaluation of the Xeon phi processor as a technology for the acceleration of real-time control in high-order adaptive optics systems

NASA Astrophysics Data System (ADS)

Barr, David; Basden, Alastair; Dipper, Nigel; Schwartz, Noah; Vick, Andy; Schnetler, Hermine

2014-08-01

We present wavefront reconstruction acceleration of high-order AO systems using an Intel Xeon Phi processor. The Xeon Phi is a coprocessor providing many integrated cores and designed for accelerating compute intensive, numerical codes. Unlike other accelerator technologies, it allows virtually unchanged C/C++ to be recompiled to run on the Xeon Phi, giving the potential of making development, upgrade and maintenance faster and less complex. We benchmark the Xeon Phi in the context of AO real-time control by running a matrix vector multiply (MVM) algorithm. We investigate variability in execution time and demonstrate a substantial speed-up in loop frequency. We examine the integration of a Xeon Phi into an existing RTC system and show that performance improvements can be achieved with limited development effort.

The United States Particle Accelerator School: Educating the Next Generation of Accelerator Scientists and Engineers

NASA Astrophysics Data System (ADS)

Barletta, William A.

2009-03-01

Only a handful of universities in the US offer any formal training in accelerator science. The United States Particle Accelerator School (USPAS) is National Graduate Educational Program that has developed a highly successful educational paradigm that, over the past twenty-years, has granted more university credit in accelerator/beam science and technology than any university in the world. Sessions are held twice annually, hosted by major US research universities that approve course credit, certify the USPAS faculty, and grant course credit. The USPAS paradigm is readily extensible to other rapidly developing, cross-disciplinary research areas such as high energy density physics.

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.

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.

Combined Mini-Cylex & Disk Acceleration Tests in Type K Copper.

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

Maines, Warren Russell; Kittell, David E.; Hobbs, Michael L.

We combined the miniature cylinder expansion test (Mini-Cylex), with the Disk Acceleration Test (DAX) using Type K copper, Picatinny Liquid Explosive, and photonic Doppler velocimetry. We estimated the CJ state using plate reverberation methods at the test cap. We extracted velocities at 2, 7, and 10 volume expansions to fit Jones-Wilkins-Lee Equation of State at the tube wall. And we estimated Gurney velocity both at the test cap and tube wall. Our experiments and simulations are within expected uncertainty. The test and the analysis effectively reduce costs while keeping similar fidelity compared with more expensive tests.

High spatial resolution measurements of ram accelerator gas dynamic phenomena

NASA Technical Reports Server (NTRS)

Hinkey, J. B.; Burnham, E. A.; Bruckner, A. P.

1992-01-01

High spatial resolution experimental tube wall pressure measurements of ram accelerator gas dynamic phenomena are presented. The projectile resembles the centerbody of a ramjet and travels supersonically through a tube filled with a combustible gaseous mixture, with the tube acting as the outer cowling. Pressure data are recorded as the projectile passes by sensors mounted in the tube wall at various locations along the tube. Data obtained by using a special highly instrumented section of tube has allowed the recording of gas dynamic phenomena with a spatial resolution on the order of one tenth the projectile length. High spatial resolution tube wall pressure data from the three regimes of propulsion studied to date (subdetonative, transdetonative, and superdetonative) are presented and reveal the 3D character of the flowfield induced by projectile fins and the canting of the projectile body relative to the tube wall. Also presented for comparison to the experimental data are calculations made with an inviscid, 3D CFD code.

Study of the seismic performance of hybrid A-frame micropile/MSE (mechanically stabilized earth) wall

NASA Astrophysics Data System (ADS)

Chen, Yumin; Zhang, Zhichao; Liu, Hanlong

2017-04-01

The Hybrid A-Frame Micropile/MSE (mechanically stabilized earth) Wall suitable for mountain roadways is put forward in this study: a pair of vertical and inclined micropiles goes through the backfill region of a highway MSE Wall from the road surface and are then anchored into the foundation. The pile cap and grade beam are placed on the pile tops, and then a road barrier is connected to the grade beam by connecting pieces. The MSE wall's global stability, local stability and impact resistance of the road barrier can be enhanced simultaneously by this design. In order to validate the serviceability of the hybrid A-frame micropile/MSE wall and the reliability of the numerical method, scale model tests and a corresponding numerical simulation were conducted. Then, the seismic performance of the MSE walls before and after reinforcement with micropiles was studied comparatively through numerical methods. The results indicate that the hybrid A-frame micropile/MSE wall can effectively control earthquake-induced deformation, differential settlement at the road surface, bearing pressure on the bottom and acceleration by means of a rigid-soft combination of micropiles and MSE. The accumulated displacement under earthquakes with amplitude of 0.1‒0.5 g is reduced by 36.3%‒46.5%, and the acceleration amplification factor on the top of the wall is reduced by 13.4%, 15.7% and 19.3% based on 0.1, 0.3 and 0.5 g input earthquake loading, respectively. In addition, the earthquake-induced failure mode of the MSE wall in steep terrain is the sliding of the MSE region along the backslope, while the micropiles effectively control the sliding trend. The maximum earthquake-induced pile bending moment is in the interface between MSE and slope foundation, so it is necessary to strengthen the reinforcement of the pile body in the interface. Hence, it is proven that the hybrid A-frame micropile/MSE wall system has good seismic performance.

Computational Accelerator Physics. Proceedings

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

Bisognano, J.J.; Mondelli, A.A.

1997-04-01

The sixty two papers appearing in this volume were presented at CAP96, the Computational Accelerator Physics Conference held in Williamsburg, Virginia from September 24{minus}27,1996. Science Applications International Corporation (SAIC) and the Thomas Jefferson National Accelerator Facility (Jefferson lab) jointly hosted CAP96, with financial support from the U.S. department of Energy`s Office of Energy Research and the Office of Naval reasearch. Topics ranged from descriptions of specific codes to advanced computing techniques and numerical methods. Update talks were presented on nearly all of the accelerator community`s major electromagnetic and particle tracking codes. Among all papers, thirty of them are abstracted formore » the Energy Science and Technology database.(AIP)« less

Pulse - Accelerator Science in Medicine

Science.gov Websites

intermediate machines. Each generation of particle accelerators build on the accomp-lishments of the previous ones, raising the level of technology ever higher. Security, Privacy Legal

Numerical Study of Single Bubble Growth on and Departure from a Horizontal Superheated Wall by Three-dimensional Lattice Boltzmann Method

NASA Astrophysics Data System (ADS)

Feng, Yuan; Li, Hui-Xiong; Guo, Kai-Kai; Zhao, Jian-Fu; Wang, Tai

2018-05-01

A three-dimensional hybrid lattice Boltzmann method was used to simulate the progress of a single bubble's growth and departure from a horizontal superheated wall. The evolutionary process of the bubble shapes and also the temperature fields during pool nucleate boiling were obtained and the influence of the gravitational acceleration on the bubble departure diameter (BDD), the bubble release frequency (BRF) and the heat flux on the superheated wall was analyzed. The simulation results obtained by the present three-dimensional numerical studies demonstrate that the BDD is proportional to g^{-0.301}, the BRF is proportional to g^{-0.58}, and the averaged wall heat flux is proportional to g^{0.201}, where g is the gravitational acceleration. These results are in good agreement with the common-used experimental correlations, indicating the rationality of the present numerical model and results.

Methods for elimination of dampness in Building walls

NASA Astrophysics Data System (ADS)

Campian, Cristina; Pop, Maria

2016-06-01

Dampness elimination in building walls is a very sensitive problem, with high costs. Many methods are used, as: chemical method, electro osmotic method or physical method. The RECON method is a representative and a sustainable method in Romania. Italy has the most radical method from all methods. The technology consists in cutting the brick walls, insertion of a special plastic sheeting and injection of a pre-mixed anti-shrinking mortar.

Microfluidics with fluid walls.

PubMed

Walsh, Edmond J; Feuerborn, Alexander; Wheeler, James H R; Tan, Ann Na; Durham, William M; Foster, Kevin R; Cook, Peter R

2017-10-10

Microfluidics has great potential, but the complexity of fabricating and operating devices has limited its use. Here we describe a method - Freestyle Fluidics - that overcomes many key limitations. In this method, liquids are confined by fluid (not solid) walls. Aqueous circuits with any 2D shape are printed in seconds on plastic or glass Petri dishes; then, interfacial forces pin liquids to substrates, and overlaying an immiscible liquid prevents evaporation. Confining fluid walls are pliant and resilient; they self-heal when liquids are pipetted through them. We drive flow through a wide range of circuits passively by manipulating surface tension and hydrostatic pressure, and actively using external pumps. Finally, we validate the technology with two challenging applications - triggering an inflammatory response in human cells and chemotaxis in bacterial biofilms. This approach provides a powerful and versatile alternative to traditional microfluidics.The complexity of fabricating and operating microfluidic devices limits their use. Walsh et al. describe a method in which circuits are printed as quickly and simply as writing with a pen, and liquids in them are confined by fluid instead of solid walls.

Second International Conference on Accelerating Biopharmaceutical Development

PubMed Central

2009-01-01

The Second International Conference on Accelerating Biopharmaceutical Development was held in Coronado, California. The meeting was organized by the Society for Biological Engineering (SBE) and the American Institute of Chemical Engineers (AIChE); SBE is a technological community of the AIChE. Bob Adamson (Wyeth) and Chuck Goochee (Centocor) were co-chairs of the event, which had the theme “Delivering cost-effective, robust processes and methods quickly and efficiently.” The first day focused on emerging disruptive technologies and cutting-edge analytical techniques. Day two featured presentations on accelerated cell culture process development, critical quality attributes, specifications and comparability, and high throughput protein formulation development. The final day was dedicated to discussion of technology options and new analysis methods provided by emerging disruptive technologies; functional interaction, integration and synergy in platform development; and rapid and economic purification process development. PMID:20065637

Principles of Induction Accelerators

NASA Astrophysics Data System (ADS)

Briggs*, Richard J.

The basic concepts involved in induction accelerators are introduced in this chapter. The objective is to provide a foundation for the more detailed coverage of key technology elements and specific applications in the following chapters. A wide variety of induction accelerators are discussed in the following chapters, from the high current linear electron accelerator configurations that have been the main focus of the original developments, to circular configurations like the ion synchrotrons that are the subject of more recent research. The main focus in the present chapter is on the induction module containing the magnetic core that plays the role of a transformer in coupling the pulsed power from the modulator to the charged particle beam. This is the essential common element in all these induction accelerators, and an understanding of the basic processes involved in its operation is the main objective of this chapter. (See [1] for a useful and complementary presentation of the basic principles in induction linacs.)

Effect of gravitational acceleration, hypokinesia and hypodynamia on the structure of the intestinal vascular bed

NASA Technical Reports Server (NTRS)

Nikitin, M. V.

1980-01-01

A series of experiments comparing single and combined effects of hypokinesia and gravitational acceleration on morphology of intestinal blood vessels are discussed. Results indicate that hypokinesia has a whole body nonspecific effect reflected even in an organ whose activity shows little or no change due to hypokinesia. In early hypokinetic stages blood redistribution caused anorexia, intestinal atonia, and secretory disruption. Destructive changes from further exposure include aneurisms, varicoses, extravascular movement of blood elements, and vascular wall muscle fiber degeneration. The effect of acceleration is greatest in the ventrodorsal direction. Changes due to acceleration then hypokinesia are like those due to hypokinesia alone; changes due to acceleration before and after hypokinesia are like those due to acceleration. Adaptation raises acceleration tolerance but the effects do not survive four-week hypokinesia.

Plant cell wall proteomics: the leadership of Arabidopsis thaliana

PubMed Central

Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth

2013-01-01

Plant cell wall proteins (CWPs) progressively emerged as crucial components of cell walls although present in minor amounts. Cell wall polysaccharides such as pectins, hemicelluloses, and cellulose represent more than 90% of primary cell wall mass, whereas hemicelluloses, cellulose, and lignins are the main components of lignified secondary walls. All these polymers provide mechanical properties to cell walls, participate in cell shape and prevent water loss in aerial organs. However, cell walls need to be modified and customized during plant development and in response to environmental cues, thus contributing to plant adaptation. CWPs play essential roles in all these physiological processes and particularly in the dynamics of cell walls, which requires organization and rearrangements of polysaccharides as well as cell-to-cell communication. In the last 10 years, plant cell wall proteomics has greatly contributed to a wider knowledge of CWPs. This update will deal with (i) a survey of plant cell wall proteomics studies with a focus on Arabidopsis thaliana; (ii) the main protein families identified and the still missing peptides; (iii) the persistent issue of the non-canonical CWPs; (iv) the present challenges to overcome technological bottlenecks; and (v) the perspectives beyond cell wall proteomics to understand CWP functions. PMID:23641247

Wall shear stress estimation in the aorta: Impact of wall motion, spatiotemporal resolution, and phase noise.

PubMed

Zimmermann, Judith; Demedts, Daniel; Mirzaee, Hanieh; Ewert, Peter; Stern, Heiko; Meierhofer, Christian; Menze, Bjoern; Hennemuth, Anja

2018-04-01

Wall shear stress (WSS) presents an important parameter for assessing blood flow characteristics and evaluating flow-mediated lesions in the aorta. To investigate the robustness of WSS and oscillatory shear index (OSI) estimation based on 4D flow MRI against vessel wall motion, spatiotemporal resolution, and velocity encoding (VENC). Simulated and prospective. Synthetic 4D flow MRI data of the aorta, simulated using the Lattice-Boltzmann method; in vivo 4D flow MRI data of the aorta from healthy volunteers (n = 11) and patients with congenital heart defects (n = 17). 1.5T; 4D flow MRI with PEAK-GRAPPA acceleration and prospective electrocardiogram triggering. Predicated upon 3D cubic B-splines interpolation of the image velocity field, WSS was estimated in mid-systole, early-diastole, and late-diastole and OSI was derived. We assessed the impact of spatiotemporal resolution and phase noise, and compared results based on tracked-using deformable registration-and static vessel wall location. Bland-Altman analysis to assess WSS/OSI differences; Hausdorff distance (HD) to assess wall motion; and Pearson's correlation coefficient (PCC) to assess correlation of HD with WSS. Synthetic data results show systematic over-/underestimation of WSS when different spatial resolution (mean ± 1.96 SD up to -0.24 ± 0.40 N/m 2 and 0.5 ± 1.38 N/m 2 for 8-fold and 27-fold voxel size, respectively) and VENC-depending phase noise (mean ± 1.96 SD up to 0.31 ± 0.12 N/m 2 and 0.94 ± 0.28 N/m 2 for 2-fold and 4-fold VENC increase, respectively) are given. Neglecting wall motion when defining the vessel wall perturbs WSS estimates to a considerable extent (1.96 SD up to 1.21 N/m 2 ) without systematic over-/underestimation (Bland-Altman mean range -0.06 to 0.05). In addition to sufficient spatial resolution and velocity to noise ratio, accurate tracking of the vessel wall is essential for reliable image-based WSS estimation and should not be

Emerging technology for transonic wind-tunnel-wall interference assessment and corrections

NASA Technical Reports Server (NTRS)

Newman, P. A.; Kemp, W. B., Jr.; Garriz, J. A.

1988-01-01

Several nonlinear transonic codes and a panel method code for wind tunnel/wall interference assessment and correction (WIAC) studies are reviewed. Contrasts between two- and three-dimensional transonic testing factors which affect WIAC procedures are illustrated with airfoil data from the NASA/Langley 0.3-meter transonic cyrogenic tunnel and Pathfinder I data. Also, three-dimensional transonic WIAC results for Mach number and angle-of-attack corrections to data from a relatively large 20 deg swept semispan wing in the solid wall NASA/Ames high Reynolds number Channel I are verified by three-dimensional thin-layer Navier-Stokes free-air solutions.

A Near-Wall Reynolds-Stress Closure Without Wall Normals

NASA Technical Reports Server (NTRS)

Yuan, S. P.; So, R. M. C.

1997-01-01

Turbulent wall-bounded complex flows are commonly encountered in engineering practice and are of considerable interest in a variety of industrial applications. The presence of a wall significantly affects turbulence characteristics. In addition to the wall effects, turbulent wall-bounded flows become more complicated by the presence of additional body forces (e.g. centrifugal force and Coriolis force) and complex geometry. Most near-wall Reynolds stress models are developed from a high-Reynolds-number model which assumes turbulence is homogenous (or quasi-homogenous). Near-wall modifications are proposed to include wall effects in near-wall regions. In this process, wall normals are introduced. Good predictions could be obtained by Reynolds stress models with wall normals. However, ambiguity arises when the models are applied in flows with multiple walls. Many models have been proposed to model turbulent flows. Among them, Reynolds stress models, in which turbulent stresses are obtained by solving the Reynolds stress transport equations, have been proved to be the most successful ones. To apply the Reynolds stress models to wall-bounded flows, near-wall corrections accounting for the wall effects are needed, and the resulting models are called near-wall Reynolds stress models. In most of the existing near-wall models, the near-wall corrections invoke wall normals. These wall-dependent near-wall models are difficult to implement for turbulent flows with complex geometry and may give inaccurate predictions due to the ambiguity of wall normals at corners connecting multiple walls. The objective of this study is to develop a more general and flexible near-wall Reynolds stress model without using any wall-dependent variable for wall-bounded turbulent flows. With the aid of near-wall asymptotic analysis and results of direct numerical simulation, a new near-wall Reynolds stress model (NNWRS) is formulated based on Speziale et al.'s high-Reynolds-stress model with wall

Through-the-wall surveillance for homeland security and law enforcement

NASA Astrophysics Data System (ADS)

Borek, Stanley E.; Clarke, Bernard J.; Costianes, Peter J.

2005-05-01

The Air Force Research Laboratory Information Directorate (AFRL/IF), under sponsorship of the Department of Justice's (DOJ), National Institute of Justice (NIJ) Office of Science and Technology (OS&T), is currently developing and evaluating advanced Through the Wall Surveillance (TWS) technologies. These technologies are partitioned into two categories: inexpensive, handheld systems for locating an individual(s) behind a wall or door; and portable, personal computer (PC) based standoff systems to enable the determination of events during critical incident situations. The technologies utilized are primarily focused on active radars operating in the UHF, L, S (ultra wideband (UWB)), X, and Ku Bands. The data displayed by these systems is indicative of range (1 Dimension), or range and azimuth (2 Dimensions) to the moving individual(s). This paper will highlight the technologies employed in five (5) prototype TWS systems delivered to NIJ and AFRL/IF for test and evaluation. It will discuss the systems backgrounds, applications, current states of evolution, and future plans for enhanced assessment.

Low-cost sustainable wall construction system

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

Vohra, A.; Rosenfeld, A.H.

1998-07-01

Houses with no wall cavities, such as those made of adobe, stone, brick, or block, have poor thermal properties but are rarely insulated because of the cost and difficulty of providing wall insulation. A simple, low-cost technique using loose-fill indigenous materials has been demonstrated for the construction of highly insulated walls or the retrofit of existing walls in such buildings. Locally available pumice, in sandbags stacked along the exterior wall of an adobe house in New Mexico, added a thermal resistance (R) of 16 F{sm{underscore}bullet}ft{sup 2}{sm{underscore}bullet}h/Btu (2.8 m{sup 2}{sm{underscore}bullet}K/W). The total cost of the sandbag insulation wall retrofit wasmore » $3.76 per square foot ($$40.50/m{sup 2}). Computer simulations of the adobe house using DOE 2.1E show savings of $$275 per year, corresponding to 50% reduction in heating energy consumption. The savings-to-investment ratio ranges from 1.1 to 3.2, so the cost of conserved energy is lower than the price of propane, natural gas and electric heat, making the system cost-effective. Prototype stand-alone walls were also constructed using fly ash and sawdust blown into continuous polypropylene tubing, which was folded between corner posts as it was filled to form the shape of the wall. Other materials could also be used. The inexpensive technique solves the problem of insulating solid-wall hours and constructing new houses without specialized equipment and skills, thereby saving energy, reducing greenhouse gas emissions, and improving comfort for people in many countries. The US Department of Energy (DOE) has filed patent applications on this technology, which is part of a DOE initiative on sustainable building envelope materials and systems.« less

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.

Particle Trajectories in Rotating Wall Cell Culture Devices

NASA Technical Reports Server (NTRS)

Ramachandran N.; Downey, J. P.

1999-01-01

Cell cultures are extremely important to the medical community since such cultures provide an opportunity to perform research on human tissue without the concerns inherent in experiments on individual humans. Development of cells in cultures has been found to be greatly influenced by the conditions of the culture. Much work has focused on the effect of the motions of cells in the culture relative to the solution. Recently rotating wall vessels have been used with success in achieving improved cellular cultures. Speculation and limited research have focused on the low shear environment and the ability of rotating vessels to keep cells suspended in solution rather than floating or sedimenting as the primary reasons for the improved cellular cultures using these devices. It is widely believed that the cultures obtained using a rotating wall vessel simulates to some degree the effect of microgravity on cultures. It has also been speculated that the microgravity environment may provide the ideal acceleration environment for culturing of cellular tissues due to the nearly negligible levels of sedimentation and shear possible. This work predicts particle trajectories of cells in rotating wall vessels of cylindrical and annular design consistent with the estimated properties of typical cellular cultures. Estimates of the shear encountered by cells in solution and the interactions with walls are studied. Comparisons of potential experiments in ground and microgravity environments are performed.

Beam Position Monitoring in the CSU Accelerator Facility

NASA Astrophysics Data System (ADS)

Einstein, Joshua; Vankeuren, Max; Watras, Stephen

2014-03-01

A Beam Position Monitoring (BPM) system is an integral part of an accelerator beamline, and modern accelerators can take advantage of newer technologies and designs when creating a BPM system. The Colorado State University (CSU) Accelerator Facility will include four stripline detectors mounted around the beamline, a low-noise analog front-end, and digitization and interface circuitry. The design will support a sampling rate greater than 10 Hz and sub-100 μm accuracy.

Knudsen paradox in granular gases and the roles of thermal and athermal walls

NASA Astrophysics Data System (ADS)

Gupta, Ronak; Alam, Meheboob

2017-11-01

The well-known `Knudsen-paradox' (which refers to the decrease of the mass-flow rate of a gas with increasing Knudsen number Kn , reaching a minimum at Kn O(1) and increasing logarithmically with Kn as Kn -> ∞) is revisited using direct simulation Monte Carlo (DSMC) method. It is shown that the `Knudsen-paradox' survives in the acceleration-driven Poiseuille flow of a granular gas in contact with thermal-walls. This result is in contradiction with recent molecular dynamics simulations (Alam et al., J. Fluid Mech., vol. 782, 2015, pp. 99-126) that revealed the absence of the Knudsen-minimum in granular Poiseuille flow. The above conundrum is resolved by distinguishing between `thermal' and `athermal' walls, and it is shown that, for both molecular and granular gases, the momentum-transfer to athermal-walls is much lower than that to thermal-walls which is directly responsible for the ``anomalous'' flow-rate-variation with Kn . In the continuum limit of Kn -> 0 , the athermal walls are found to be closely related to `non-flux/adiabatic' walls. The underlying mechanistic arguments lead to Maxwell's slip-boundary condition and a possible characterization of athermal walls in terms of an effective specularity coefficient is discussed.

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

Research on Acceleration Compensation Strategy of Electric Vehicle Based on Fuzzy Control Theory

NASA Astrophysics Data System (ADS)

Zhu, Tianjun; Li, Bin; Zong, Changfu; Wei, Zhicheng

2017-09-01

Nowadays, the driving technology of electric vehicle is developing rapidly. There are many kinds of methods in driving performance control technology. The paper studies the acceleration performance of electric vehicle. Under the premise of energy management, an acceleration power compensation method by fuzzy control theory based on driver intention recognition is proposed, which can meet the driver’s subjective feelings better. It avoids the problem that the pedal opening and power output are single correspondence when the traditional vehicle accelerates. Through the simulation test, this method can significantly improve the performance of acceleration and output torque smoothly in non-emergency acceleration to ensure vehicle comfortable and stable.

Laser-driven ion acceleration: methods, challenges and prospects

NASA Astrophysics Data System (ADS)

Badziak, J.

2018-01-01

The recent development of laser technology has resulted in the construction of short-pulse lasers capable of generating fs light pulses with PW powers and intensities exceeding 1021 W/cm2, and has laid the basis for the multi-PW lasers, just being built in Europe, that will produce fs pulses of ultra-relativistic intensities ~ 1023 - 1024 W/cm2. The interaction of such an intense laser pulse with a dense target can result in the generation of collimated beams of ions of multi-MeV to GeV energies of sub-ps time durations and of extremely high beam intensities and ion fluencies, barely attainable with conventional RF-driven accelerators. Ion beams with such unique features have the potential for application in various fields of scientific research as well as in medical and technological developments. This paper provides a brief review of state-of-the art in laser-driven ion acceleration, with a focus on basic ion acceleration mechanisms and the production of ultra-intense ion beams. The challenges facing laser-driven ion acceleration studies, in particular those connected with potential applications of laser-accelerated ion beams, are also discussed.

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.

Channel Wall Nozzle Hot-fire Tests

NASA Image and Video Library

2018-03-16

A subscale channel wall nozzle is hot-fire tested in November 2017 at NASA's Marshall Space Flight Center. The nozzle was fabricated using three separate, state-of-the-art, advanced manufacturing technologies including a new process called Laser Wire Direct Closeout that was co-developed and advanced at Marshall.

Acceleration of domain wall movement by photoirradiation in perovskite-type cobaltite

NASA Astrophysics Data System (ADS)

Okimoto, Y.; Kurashima, M.; Seko, K.; Ishikawa, T.; Onda, K.; Koshihara, S.; Kyomen, T.; Itoh, M.

2011-04-01

Femtosecond reflection spectroscopy was performed on a perovskite-type cobalt oxide, namely, Pr0.5Ca0.5CoO3, that undergoes a photoinduced spin-state transition. After photoirradiation at 30 K, the time profile of the reflectance change shows a broad peak reflecting the propagation of the photodomain (about 60 Co sites per one photon). Analysis of the peak position indicates the sudden increase of the velocity of the propagation with increasing the excitation intensity. Such acceleration with increase in fluence originates from an abrupt sound velocity change driven by a cooperative photoinduced structural transition.

EuCARD2: enhanced accelerator research and development in Europe

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. EuCARD2 is an European research project which will be realized during 2013-2017 inside the EC FP7 framework. The project concerns the development and coordination of European Accelerator Research and Development. The project is particularly important, to a number of domestic laboratories, due to some plans to build large accelerator infrastructure in Poland. Large accelerator infrastructure of fundamental and applied research character stimulates around it the development and industrial applications as well as biomedical of advanced accelerators, material research and engineering, cryo-technology, mechatronics, robotics, and in particular electronics - like networked measurement and control systems, sensors, computer systems, automation and control systems. The paper presents a digest of the European project EuCARD2 which is Enhanced European Coordination for Accelerator Research and Development. The paper presents a digest of the research results and assumptions in the domain of accelerator science and technology in Europe, shown during the final fourth annual meeting of the EuCARD - European Coordination of Accelerator R&D, and the kick-off meeting of the EuCARD2. There are debated a few basic groups of accelerator systems components like: measurement - control networks of large geometrical extent, multichannel systems for large amounts of metrological data acquisition, precision photonic networks of reference time, frequency and phase distribution, high field magnets, superconducting cavities, novel beam collimators, etc. The paper bases on the following materials: Internet and Intranet documents combined with EuCARD2, Description of Work FP7 EuCARD-2 DoW-312453, 2013-02-13, and discussions and preparatory materials worked on by Eucard-2 initiators.

Applications of High Intensity Proton Accelerators

NASA Astrophysics Data System (ADS)

Raja, Rajendran; Mishra, Shekhar

2010-06-01

Superconducting radiofrequency linac development at Fermilab / S. D. Holmes -- Rare muon decay experiments / Y. Kuno -- Rare kaon decays / D. Bryman -- Muon collider / R. B. Palmer -- Neutrino factories / S. Geer -- ADS and its potential / J.-P. Revol -- ADS history in the USA / R. L. Sheffield and E. J. Pitcher -- Accelerator driven transmutation of waste: high power accelerator for the European ADS demonstrator / J. L. Biarrotte and T. Junquera -- Myrrha, technology development for the realisation of ADS in EU: current status & prospects for realisation / R. Fernandez ... [et al.] -- High intensity proton beam production with cyclotrons / J. Grillenberger and M. Seidel -- FFAG for high intensity proton accelerator / Y. Mori -- Kaon yields for 2 to 8 GeV proton beams / K. K. Gudima, N. V. Mokhov and S. I. Striganov -- Pion yield studies for proton driver beams of 2-8 GeV kinetic energy for stopped muon and low-energy muon decay experiments / S. I. Striganov -- J-Parc accelerator status and future plans / H. Kobayashi -- Simulation and verification of DPA in materials / N. V. Mokhov, I. L. Rakhno and S. I. Striganov -- Performance and operational experience of the CNGS facility / E. Gschwendtner -- Particle physics enabled with super-conducting RF technology - summary of working group 1 / D. Jaffe and R. Tschirhart -- Proton beam requirements for a neutrino factory and muon collider / M. S. Zisman -- Proton bunching options / R. B. Palmer -- CW SRF H linac as a proton driver for muon colliders and neutrino factories / M. Popovic, C. M. Ankenbrandt and R. P. Johnson -- Rapid cycling synchrotron option for Project X / W. Chou -- Linac-based proton driver for a neutrino factory / R. Garoby ... [et al.] -- Pion production for neutrino factories and muon colliders / N. V. Mokhov ... [et al.] -- Proton bunch compression strategies / V. Lebedev -- Accelerator test facility for muon collider and neutrino factory R&D / V. Shiltsev -- The superconducting RF linac for muon

Flattening filter-free accelerators: a report from the AAPM Therapy Emerging Technology Assessment Work Group.

PubMed

Xiao, Ying; Kry, Stephen F; Popple, Richard; Yorke, Ellen; Papanikolaou, Niko; Stathakis, Sotirios; Xia, Ping; Huq, Saiful; Bayouth, John; Galvin, James; Yin, Fang-Fang

2015-05-08

This report describes the current state of flattening filter-free (FFF) radiotherapy beams implemented on conventional linear accelerators, and is aimed primarily at practicing medical physicists. The Therapy Emerging Technology Assessment Work Group of the American Association of Physicists in Medicine (AAPM) formed a writing group to assess FFF technology. The published literature on FFF technology was reviewed, along with technical specifications provided by vendors. Based on this information, supplemented by the clinical experience of the group members, consensus guidelines and recommendations for implementation of FFF technology were developed. Areas in need of further investigation were identified. Removing the flattening filter increases beam intensity, especially near the central axis. Increased intensity reduces treatment time, especially for high-dose stereotactic radiotherapy/radiosurgery (SRT/SRS). Furthermore, removing the flattening filter reduces out-of-field dose and improves beam modeling accuracy. FFF beams are advantageous for small field (e.g., SRS) treatments and are appropriate for intensity-modulated radiotherapy (IMRT). For conventional 3D radiotherapy of large targets, FFF beams may be disadvantageous compared to flattened beams because of the heterogeneity of FFF beam across the target (unless modulation is employed). For any application, the nonflat beam characteristics and substantially higher dose rates require consideration during the commissioning and quality assurance processes relative to flattened beams, and the appropriate clinical use of the technology needs to be identified. Consideration also needs to be given to these unique characteristics when undertaking facility planning. Several areas still warrant further research and development. Recommendations pertinent to FFF technology, including acceptance testing, commissioning, quality assurance, radiation safety, and facility planning, are presented. Examples of clinical

Wall shear stress measurements using a new transducer

NASA Technical Reports Server (NTRS)

Vakili, A. D.; Wu, J. M.; Lawing, P. L.

1986-01-01

A new instrument has been developed for direct measurement of wall shear stress. This instrument is simple and symmetric in design with small moving mass and no internal friction. Features employed in the design of this instrument eliminate most of the difficulties associated with the traditional floating element balances. Vibration problems associated with the floating element skin friction balances have been found to be minimized by the design features and optional damping provided. The unique design of this instrument eliminates or reduces the errors associated with conventional floating-element devices: such as errors due to gaps, pressure gradient, acceleration, heat transfer and temperature change. The instrument is equipped with various sensing systems and the output signal is a linear function of the wall shear stress. Measurement made in three different tunnels show good agreement with theory and data obtained by the floating element devices.

Structural Properties of EB-Welded AlSi10Mg Thin-Walled Pressure Vessels Produced by AM-SLM Technology

NASA Astrophysics Data System (ADS)

Nahmany, Moshe; Stern, Adin; Aghion, Eli; Frage, Nachum

2017-10-01

Additive manufacturing of metals by selective laser melting (AM-SLM) is hampered by significant limitations in product size due to the limited dimensions of printing trays. Electron beam welding (EBW) is a well-established process that results in relatively minor metallurgical modifications in workpieces due to the ability of EBW to pass high-density energy to the related substance. The present study aims to evaluate structural properties of EB-welded AlSi10Mg thin-walled pressure vessels produced from components prepared by SLM technology. Following the EB welding process, leak and burst tests were conducted, as was fractography analysis. The welded vessels showed an acceptable holding pressure of 30 MPa, with a reasonable residual deformation up to 2.3% and a leak rate better than 1 × 10-8 std-cc s-1 helium. The failures that occurred under longitudinal stresses reflected the presence of two weak locations in the vessels, i.e., the welded joint region and the transition zone between the vessel base and wall. Fractographic analysis of the fracture surfaces of broken vessels displayed the ductile mode of the rupture, with dimples of various sizes, depending on the failure location.

rf breakdown tests of mm-wave metallic accelerating structures

DOE PAGES

Dal Forno, Massimo; Dolgashev, Valery; Bowden, Gordon; ...

2016-01-06

In this study, we explore the physics and frequency-scaling of vacuum rf breakdowns at sub-THz frequencies. We present the experimental results of rf tests performed in metallic mm-wave accelerating structures. These experiments were carried out at the facility for advanced accelerator experimental tests (FACET) at the SLAC National Accelerator Laboratory. The rf fields were excited by the FACET ultrarelativistic electron beam. We compared the performances of metal structures made with copper and stainless steel. The rf frequency of the fundamental accelerating mode, propagating in the structures at the speed of light, varies from 115 to 140 GHz. The traveling wavemore » structures are 0.1 m long and composed of 125 coupled cavities each. We determined the peak electric field and pulse length where the structures were not damaged by rf breakdowns. We calculated the electric and magnetic field correlated with the rf breakdowns using the FACET bunch parameters. The wakefields were calculated by a frequency domain method using periodic eigensolutions. Such a method takes into account wall losses and is applicable to a large variety of geometries. The maximum achieved accelerating gradient is 0.3 GV/m with a peak surface electric field of 1.5 GV/m and a pulse length of about 2.4 ns.« less

LiveWall Operational Evaluation: Seattle Law Enforcement Pilot

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

Barr, Jonathan L.; Burtner, Edwin R.; Stein, Steven L.

2013-10-01

The LiveWall concept envisioned as an outgrowth of the Precision Information Environment (PIE) project allows communications between separate groups using interactive video, audio, and a shared desktop environment; this allows everyone to participate and collaborate in real time, regardless of location. The LiveWall concept provides a virtual window to other locations, where all parties can interact and collaboratively work with each other. This functionality is intended to improve multi-site coordination amongst emergency operations centers (EOC), field operations sites and across organizations and jurisdictions to accommodate communications during routine and emergency events. For the initial LiveWall operational evaluation PNNL partnered withmore » the Seattle Police Department (SPD). This partnership allowed for the creation of an excellent LiveWall test bed specific to law enforcement. This partnership made it possible to test the LiveWall concept with scenarios involving the many facets of the law enforcement work done by SPD. PNNL and SPD agreed that integrating the systems into operations for a real event would be the best test of the technology and give SPD staff greater visibility into the functionality and benefits offered by the LiveWall concept.« less

Accelerated killing of cancer cells using a multifunctional single-walled carbon nanotube-based system for targeted drug delivery in combination with photothermal therapy.

PubMed

Jeyamohan, Prashanti; Hasumura, Takashi; Nagaoka, Yutaka; Yoshida, Yasuhiko; Maekawa, Toru; Kumar, D Sakthi

2013-01-01

The photothermal effect of single-walled carbon nanotubes (SWCNTs) in combination with the anticancer drug doxorubicin (DOX) for targeting and accelerated destruction of breast cancer cells is demonstrated in this paper. A targeted drug-delivery system was developed for selective killing of breast cancer cells with polyethylene glycol biofunctionalized and DOX-loaded SWCNTs conjugated with folic acid. In our work, in vitro drug-release studies showed that the drug (DOX) binds at physiological pH (pH 7.4) and is released only at a lower pH, ie, lysosomal pH (pH 4.0), which is the characteristic pH of the tumor environment. A sustained release of DOX from the SWCNTs was observed for a period of 3 days. SWCNTs have strong optical absorbance in the near-infrared (NIR) region. In this special spectral window, biological systems are highly transparent. Our study reports that under laser irradiation at 800 nm, SWCNTs exhibited strong light-heat transfer characteristics. These optical properties of SWCNTs open the way for selective photothermal ablation in cancer therapy. It was also observed that internalization and uptake of folate-conjugated NTs into cancer cells was achieved by a receptor-mediated endocytosis mechanism. Results of the in vitro experiments show that laser was effective in destroying the cancer cells, while sparing the normal cells. When the above laser effect was combined with DOX-conjugated SWCNTs, we found enhanced and accelerated killing of breast cancer cells. Thus, this nanodrug-delivery system, consisting of laser, drug, and SWCNTs, looks to be a promising selective modality with high treatment efficacy and low side effects for cancer therapy.

Overview of Accelerator Applications for Security and Defense

DOE PAGES

Antolak, Arlyn J.

2015-01-01

Particle accelerators play a key role in a broad set of defense and security applications including war-fighter and asset protection, cargo inspection, nonproliferation, materials characterization and stockpile stewardship. Accelerators can replace the high activity radioactive sources that pose a security threat for developing a radiological dispersal device and be used to produce isotopes for medical, industrial, and re-search purposes. Lastly, we present an overview of current and emerging accelerator technologies relevant to addressing the needs of defense and security.

Characterizing visible and invisible cell wall mutant phenotypes

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

Carpita, Nicholas C.; McCann, Maureen C.

2015-04-06

About 10% of a plant's genome is devoted to generating the protein machinery to synthesize, remodel, and deconstruct the cell wall. High-throughput genome sequencing technologies have enabled a reasonably complete inventory of wall-related genes that can be assembled into families of common evolutionary origin. Assigning function to each gene family member has been aided immensely by identification of mutants with visible phenotypes or by chemical and spectroscopic analysis of mutants with ‘invisible’ phenotypes of modified cell wall composition and architecture that do not otherwise affect plant growth or development. This review connects the inference of gene function on the basismore » of deviation from the wild type in genetic functional analyses to insights provided by modern analytical techniques that have brought us ever closer to elucidating the sequence structures of the major polysaccharide components of the plant cell wall.« less

X-ray driven channeling acceleration in crystals and carbon nanotubes

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

Shin, Young-Min; Still, Dean A.; Shiltsev, Vladimir

2013-12-01

Acceleration of particles channeling in a crystal by means of diffracted x-rays via Bormann anomalous transmission was conceived for heavy ions and muons by Tajima and Cavenago [Phys. Rev. Lett. 59, 1440 (1987)], which potentially offers an appreciably high field gradient on the order of GV/cm. The theoretical model of the high gradient acceleration has been studied in two kinds of atomic structure, crystals and carbon nanotubes (CNTs), with analytic calculations and electromagnetic eigenmode simulations. A range of acceleration gradients and cutoffs of the x-ray power (the lowest power limit to overcome the Bremsstrahlung radiation losses) are characterized in termsmore » of the lattice constants, unit cell sizes, and photon energies. The parametric analysis indicates that the required x-ray power can be reduced to an order of megawatt by replacing crystals with CNTs. Eventually, the equivalent dielectric approximation of a multi-wall nanotube shows that 250–810 MeV muons can be synchronously coupled with x-rays of 0.65–1.32 keV in the accelerating structure.« less

Pressure fluctuation caused by moderate acceleration

NASA Astrophysics Data System (ADS)

Tagawa, Yoshiyuki; Kurihara, Chihiro; Kiyama, Akihito

2017-11-01

Pressure fluctuation caused by acceleration of a liquid column is observed in various important technologies, e.g. water-hammer in a pipeline. The magnitude of fluctuation can be estimated by two different approaches: When the duration time of acceleration is much shorter than the propagation time for a pressure wave to travel the length of the liquid column, e.g. sudden valve closure for a long pipe, Joukowsky equation is applied. In contrast, if the acceleration duration is much longer, the liquid is modeled as a rigid column, ignoring compressibility of the fluid. However, many of practical cases exist between these two extremes. In this study we propose a model describing pressure fluctuation when the duration of acceleration is in the same order of the propagation time for a pressure wave, i.e. under moderate acceleration. The novel model considers both temporal and spatial evolutions of pressure propagation as well as gradual pressure rise during the acceleration. We conduct experiments in which we impose acceleration to a liquid with varying the length of the liquid column, acceleration duration, and properties of liquids. The ratio between the acceleration duration and the propagation time is in the range of 0.02 - 2. The model agrees well with measurement results. JSPS KAKENHI Grant Numbers 26709007 and 17H01246.

Wall characterization for through-the-wall radar applications

NASA Astrophysics Data System (ADS)

Greneker, Gene; Rausch, E. O.

2008-04-01

There has been continuing interest in the penetration of multilayer building materials, such as wood walls with air gaps and concrete hollow core block, using through-the-wall (TTW) radar systems. TTW operational techniques and signal propagation paths vary depending on how the TTW system is intended to be operated. For example, the operator of a TTW radar may be required to place the radar against the intervening wall of interest while collecting data. Other operational doctrines allow the radar to be operated in a stand-off mode from the wall. The stand-off distances can vary from feet to hundreds of feet, depending on the type of radar being used. When a signal is propagated through a multilayer wall with air gaps between the material and the wall construction uses materials of radically different dielectric constants, attenuation may not be the only effect that the probing signal experiences passing through the wall. This paper presents measurements of a hollow core concrete block wall and the measurement of a standard wall constructed of siding and wallboard. Both types of walls are typically found in most U.S. homes. These limited measurements demonstrate that the type of wall being penetrated by a wideband signal can modify the probing signal.

Successful experiments on an external MHD Accelerator: wall confinement of the plasma, annihilation of the electrothermal instability by magnetic gradient inversion, creation of a stable spiral current pattern

NASA Astrophysics Data System (ADS)

Petit, Jean-Pierre; Dore, Jean-Christophe

2013-09-01

MHD propulsion has been extensively studied since the fifties. To shift from propulsion to an MHD Aerodyne, one only needs to accelerate the air externally, along its outer skin, using Lorentz forces. We present a set of successful experiments, obtained around a model, placed in low density air. We successfully dealt with various problems: wall confinement of two-temperature plasma obtained by inversion of the magnetic pressure gradient, annihilation of the Velikhov electrothermal instability by magnetic confinement of the streamers, establishment of a stable spiral distribution of the current, obtained by an original method. Another direction of research is devoted to the study of an MHD-controlled inlet which, coupled with a turbofan engine and implying an MHD-bypass system, would extend the flight domain to hypersonic conditions. Research manager

Technology Solutions Case Study: Monitoring of Double Stud Wall Moisture Conditions in the Northeast, Devens, Massachusetts

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

None

2015-03-01

Double stud walls have a higher risk of interior-sourced condensation moisture damage when compared with high-R approaches using exterior insulating sheathing. In this project, Building Science Corporation monitored moisture conditions in double-stud walls from 2011 through 2014 at a new production house located in Devens, Massachusetts. The builder, Transformations, Inc., has been using double-stud walls insulated with 12 in. of open cell polyurethane spray foam (ocSPF); however, the company has been considering a change to netted and blown cellulose insulation for cost reasons. Cellulose is a common choice for double-stud walls because of its lower cost (in most markets). However,more » cellulose is an air-permeable insulation, unlike spray foams, which increases interior moisture risks. The team compared three double-stud assemblies: 12 in. of ocSPF, 12 in. of cellulose, and 5-½ in. of ocSPF at the exterior of a double-stud wall (to approximate conventional 2 × 6 wall construction and insulation levels, acting as a control wall). These assemblies were repeated on the north and south orientations, for a total of six assemblies.« less

Applications of the ram accelerator to hypervelocity aerothermodynamic testing

NASA Technical Reports Server (NTRS)

Bruckner, A. P.; Knowlen, C.; Hertzberg, A.

1992-01-01

A ram accelerator used as a hypervelocity launcher for large-scale aeroballistic range applications in hypersonics and aerodynamics research is presented. It is an in-bore ramjet device in which a projectile shaped like the centerbody of a supersonic ramjet is propelled down a stationary tube filled with a tailored combustible gas mixture. Ram accelerator operation has been demonstrated at 39 mm and 90 mm bores, supporting the proposition that this launcher concept can be scaled up to very large bore diameters of the order of 30-60 cm. It is concluded that high quality data obtained from the tube wall and projectile during the aceleration process itself are very useful for understanding aerothermodynamics of hypersonic flow in general, and for providing important CFD validation benchmarks.

Advances in Plexcore active layer technology systems for organic photovoltaics: roof-top and accelerated lifetime analysis of high performance organic photovoltaic cells

NASA Astrophysics Data System (ADS)

Laird, Darin W.; Vaidya, Swanand; Li, Sergey; Mathai, Mathew; Woodworth, Brian; Sheina, Elena; Williams, Shawn; Hammond, Troy

2007-09-01

We report NREL-certified efficiencies and initial lifetime data for organic photovoltaic (OPV) cells based on Plexcore PV photoactive layer and Plexcore HTL-OPV hole transport layer technology. Plexcore PV-F3, a photoactive layer OPV ink, was certified in a single-layer OPV cell at the National Renewable Energy Laboratory (NREL) at 5.4%, which represents the highest official mark for a single-layer organic solar cell. We have fabricated and measured P3HT:PCBM solar cells with a peak efficiency of 4.4% and typical efficiencies of 3 - 4% (internal, NREL-calibrated measurement) with P3HT manufactured at Plextronics by the Grignard Metathesis (GRIM) method. Outdoor and accelerated lifetime testing of these devices is reported. Both Plexcore PV-F3 and P3HT:PCBM-based OPV cells exhibit >750 hours of outdoor roof-top, non-accelerated lifetime with less than 8% loss in initial efficiency for both active layer systems when exposed continuously to the climate of Western Pennsylvania. These devices are continuously being tested to date. Accelerated testing using a high-intensity (1000W) metal-halide lamp affords shorter lifetimes; however, the true acceleration factor is still to be determined.

FIELD DEMONSTRATION OF INNOVATIVE CONDITION ASSESSMENT TECHNOLOGIES FOR WATER MAINS: ACOUSTIC PIPE WALL ASSESSMENT, INTERNAL INSPECTION, AND EXTERNAL INSPECTIONVOLUME 1: TECHNICAL REPORT AND VOLUME 2: APPENDICES

EPA Science Inventory

Nine pipe wall integrity assessment technologies were demonstrated on a 76-year-old, 2,057-ft-long portion of a cement-lined, 24-in. cast iron water main in Louisville, KY. This activity was part of a series of field demonstrations of innovative leak detection/location and condi...

A Near-Wall Reynolds-Stress Closure without Wall Normals

NASA Technical Reports Server (NTRS)

Yuan, S. P.; So, R. M. C.

1997-01-01

With the aid of near-wall asymptotic analysis and results of direct numerical simulation, a new near-wall Reynolds stress model (NNWRS) is formulated based on the SSG high-Reynolds-stress model with wall-independent near-wall corrections. Only one damping function is used for flows with a wide range of Reynolds numbers to ensure that the near-wall modifications diminish away from the walls. The model is able to reproduce complicated flow phenomena induced by complex geometry, such as flow recirculation, reattachment and boundary-layer redevelopment in backward-facing step flow and secondary flow in three-dimensional square duct flow. In simple flows, including fully developed channel/pipe flow, Couette flow and boundary-layer flow, the wall effects are dominant, and the NNWRS model predicts less degree of turbulent anisotropy in the near-wall region compared with a wall-dependent near-wall Reynolds Stress model (NWRS) developed by So and colleagues. The comparison of the predictions given by the two models rectifies the misconception that the overshooting of skin friction coefficient in backward-facing step flow prevalent in those near-wall, models with wall normal is caused by he use of wall normal.

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.

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

LOADED WAVE GUIDES FOR LINEAR ACCELERATORS

DOEpatents

Walkinshaw, W.; Mullett, L.B.

1959-12-01

A periodically loaded waveguide having substantially coaxially arranged elements which provide an axial field for the acceleration of electrons is described. Radiofrequency energy will flow in the space between the inner wall of an outer guide and the peripheries of equally spaced irises or washes arranged coaxially with each other and with the outer guide, where the loading due to the geometry of the irises is such as to reduce the phase velocity of the r-f energy flowing in the guide from a value greater than that of light to the velocity of light or less.

Theoretical and Experimental Studies in Accelerator Physics

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

Rosenzweig, James

This report describes research supported by the US Dept. of Energy Office of High Energy Physics (OHEP), performed by the UCLA Particle Beam Physics Laboratory (PBPL). The UCLA PBPL has, over the last two decades-plus, played a critical role in the development of advanced accelerators, fundamental beam physics, and new applications enabled by these thrusts, such as new types of accelerator-based light sources. As the PBPL mission is broad it is natural that it has been grown within the context of the accelerator science and technology stewardship of the OHEP. Indeed, steady OHEP support for the program has always beenmore » central to the success of the PBPL; it has provided stability, and above all has set the over-arching themes for our research directions, which have producing over 500 publications (>120 in high level journals). While other agency support has grown notably in recent years, permitting more vigorous pursuit of the program, it is transient by comparison. Beyond permitting program growth in a time of flat OHEP budgets, the influence of other agency missions is found in push to adapt advanced accelerator methods to applications, in light of the success the field has had in proof-of-principle experiments supported first by the DoE OHEP. This three-pronged PBPL program — advanced accelerators, fundamental beam physics and technology, and revolutionary applications — has produced a generation of students that have had a profound affect on the US accelerator physics community. PBPL graduates, numbering 28 in total, form a significant population group in the accelerator community, playing key roles as university faculty, scientific leaders in national labs (two have been named Panofsky Fellows at SLAC), and vigorous proponents of industrial application of accelerators. Indeed, the development of advanced RF, optical and magnet technology at the PBPL has led directly to the spin-off company, RadiaBeam Technologies, now a leading industrial

Numerical validation of axial plasma momentum lost to a lateral wall induced by neutral depletion

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

Takao, Yoshinori, E-mail: takao@ynu.ac.jp; Takahashi, Kazunori

2015-11-15

Momentum imparted to a lateral wall of a compact inductively coupled plasma thruster is numerically investigated for argon and xenon gases by a particle-in-cell simulation with Monte Carlo collisions (PIC-MCC). Axial plasma momentum lost to a lateral wall is clearly shown when axial depletion of the neutrals is enhanced, which is in qualitative agreement with the result in a recent experiment using a helicon plasma source [Takahashi et al., Phys. Rev. Lett. 114, 195001 (2015)]. The PIC-MCC calculations demonstrate that the neutral depletion causes an axially asymmetric profile of the plasma density and potential, leading to axial ion acceleration andmore » the non-negligible net axial force exerted to the lateral wall in the opposite direction of the thrust.« less

Feasibility study of an aerial manipulator interacting with a vertical wall

DTIC Science & Technology

2017-06-01

each blade . Some tests are run with different levels of PWM input and the resultant angular acceleration in each case is measured with the motion...Helicopter Near a Vertical Surface ...................29 Figure 15. Near-Wall Moment for a Single Blade Helicopter. Source: [30]. .............30...with canted propellers is proposed, so that each blade applies thrust with components in the vertical and in the horizontal plane. In Figure 10

Miniature penetrator (MinPen) acceleration recorder development test

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

Franco, R.J.; Platzbecker, M.R.

1998-08-01

The Telemetry Technology Development Department at Sandia National Laboratories actively develops and tests acceleration recorders for penetrating weapons. This new acceleration recorder (MinPen) utilizes a microprocessor-based architecture for operational flexibility while maintaining electronics and packaging techniques developed over years of penetrator testing. MinPen has been demonstrated to function in shock environments up to 20,000 Gs. The MinPen instrumentation development has resulted in a rugged, versatile, miniature acceleration recorder and is a valuable tool for penetrator testing in a wide range of applications.

Plant and algal cell walls: diversity and functionality

PubMed Central

Popper, Zoë A.; Ralet, Marie-Christine; Domozych, David S.

2014-01-01

Background Although plants and many algae (e.g. the Phaeophyceae, brown, and Rhodophyceae, red) are only very distantly related they are united in their possession of carbohydrate-rich cell walls, which are of integral importance being involved in many physiological processes. Furthermore, wall components have applications within food, fuel, pharmaceuticals, fibres (e.g. for textiles and paper) and building materials and have long been an active topic of research. As shown in the 27 papers in this Special Issue, as the major deposit of photosynthetically fixed carbon, and therefore energy investment, cell walls are of undisputed importance to the organisms that possess them, the photosynthetic eukaryotes (plants and algae). The complexities of cell wall components along with their interactions with the biotic and abiotic environment are becoming increasingly revealed. Scope The importance of plant and algal cell walls and their individual components to the function and survival of the organism, and for a number of industrial applications, are illustrated by the breadth of topics covered in this issue, which includes papers concentrating on various plants and algae, developmental stages, organs, cell wall components, and techniques. Although we acknowledge that there are many alternative ways in which the papers could be categorized (and many would fit within several topics), we have organized them as follows: (1) cell wall biosynthesis and remodelling, (2) cell wall diversity, and (3) application of new technologies to cell walls. Finally, we will consider future directions within plant cell wall research. Expansion of the industrial uses of cell walls and potentially novel uses of cell wall components are both avenues likely to direct future research activities. Fundamentally, it is the continued progression from characterization (structure, metabolism, properties and localization) of individual cell wall components through to defining their roles in almost every

Plant and algal cell walls: diversity and functionality.

PubMed

Popper, Zoë A; Ralet, Marie-Christine; Domozych, David S

2014-10-01

Although plants and many algae (e.g. the Phaeophyceae, brown, and Rhodophyceae, red) are only very distantly related they are united in their possession of carbohydrate-rich cell walls, which are of integral importance being involved in many physiological processes. Furthermore,wall components have applications within food, fuel, pharmaceuticals, fibres (e.g. for textiles and paper) and building materials and have long been an active topic of research. As shown in the 27 papers in this Special Issue, as the major deposit of photosynthetically fixed carbon, and therefore energy investment, cell walls are of undisputed importance to the organisms that possess them, the photosynthetic eukaryotes ( plants and algae). The complexities of cell wall components along with their interactions with the biotic and abiotic environment are becoming increasingly revealed. The importance of plant and algal cell walls and their individual components to the function and survival of the organism, and for a number of industrial applications, are illustrated by the breadth of topics covered in this issue, which includes papers concentrating on various plants and algae, developmental stages, organs, cell wall components, and techniques. Although we acknowledge that there are many alternative ways in which the papers could be categorized (and many would fit within several topics), we have organized them as follows: (1) cell wall biosynthesis and remodelling, (2) cell wall diversity, and (3) application of new technologies to cell walls. Finally, we will consider future directions within plant cell wall research. Expansion of the industrial uses of cell walls and potentially novel uses of cell wall components are both avenues likely to direct future research activities. Fundamentally, it is the continued progression from characterization (structure, metabolism, properties and localization) of individual cell wall components through to defining their roles in almost every aspect of plant

Cobalt-60 Machines and Medical Linear Accelerators: Competing Technologies for External Beam Radiotherapy.

PubMed

Healy, B J; van der Merwe, D; Christaki, K E; Meghzifene, A

2017-02-01

Medical linear accelerators (linacs) and cobalt-60 machines are both mature technologies for external beam radiotherapy. A comparison is made between these two technologies in terms of infrastructure and maintenance, dosimetry, shielding requirements, staffing, costs, security, patient throughput and clinical use. Infrastructure and maintenance are more demanding for linacs due to the complex electric componentry. In dosimetry, a higher beam energy, modulated dose rate and smaller focal spot size mean that it is easier to create an optimised treatment with a linac for conformal dose coverage of the tumour while sparing healthy organs at risk. In shielding, the requirements for a concrete bunker are similar for cobalt-60 machines and linacs but extra shielding and protection from neutrons are required for linacs. Staffing levels can be higher for linacs and more staff training is required for linacs. Life cycle costs are higher for linacs, especially multi-energy linacs. Security is more complex for cobalt-60 machines because of the high activity radioactive source. Patient throughput can be affected by source decay for cobalt-60 machines but poor maintenance and breakdowns can severely affect patient throughput for linacs. In clinical use, more complex treatment techniques are easier to achieve with linacs, and the availability of electron beams on high-energy linacs can be useful for certain treatments. In summary, there is no simple answer to the question of the choice of either cobalt-60 machines or linacs for radiotherapy in low- and middle-income countries. In fact a radiotherapy department with a combination of technologies, including orthovoltage X-ray units, may be an option. Local needs, conditions and resources will have to be factored into any decision on technology taking into account the characteristics of both forms of teletherapy, with the primary goal being the sustainability of the radiotherapy service over the useful lifetime of the equipment

High brightness gamma-ray production at Fermilab Accelerator Science and Technology (FAST) facility

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

Mihalcea, Daniel; Jacobson, B.; Murokh, A.

Electron beams with energies of the order of a few 100's of MeV and low transverse emittance, in combination with powerful infrared lasers, allow for the production of high quality gamma rays through Inverse Compton Scattering (ICS). At Fermilab Accelerator Science and Technology (FAST) facility, a 300 MeV beam will be used to generate gamma rays with maximum photon energies of up to ~1.5 MeV and brightness of the order of 10 21 photons/[s-(mm-mrad) 2- 0.1%BW]. Due to the low electron-beam transverse emittance, the relative bandwidth of the scattered radiation is expected to be ≤ 1%. A key challenge towardmore » the production of high radiation dose and brightness is to enhance the energy of the infrared 3 ps laser pulses to the joule level. Finally, in this contribution, we present the plans for the experimental setup, along with comprehensive numerical simulations of the ICS process.« less

High brightness gamma-ray production at Fermilab Accelerator Science and Technology (FAST) facility

DOE PAGES

Mihalcea, Daniel; Jacobson, B.; Murokh, A.; ...

2017-03-01

Electron beams with energies of the order of a few 100's of MeV and low transverse emittance, in combination with powerful infrared lasers, allow for the production of high quality gamma rays through Inverse Compton Scattering (ICS). At Fermilab Accelerator Science and Technology (FAST) facility, a 300 MeV beam will be used to generate gamma rays with maximum photon energies of up to ~1.5 MeV and brightness of the order of 10 21 photons/[s-(mm-mrad) 2- 0.1%BW]. Due to the low electron-beam transverse emittance, the relative bandwidth of the scattered radiation is expected to be ≤ 1%. A key challenge towardmore » the production of high radiation dose and brightness is to enhance the energy of the infrared 3 ps laser pulses to the joule level. Finally, in this contribution, we present the plans for the experimental setup, along with comprehensive numerical simulations of the ICS process.« less

Magnetic domain wall conduits for single cell applications.

PubMed

Donolato, M; Torti, A; Kostesha, N; Deryabina, M; Sogne, E; Vavassori, P; Hansen, M F; Bertacco, R

2011-09-07

The ability to trap, manipulate and release single cells on a surface is important both for fundamental studies of cellular processes and for the development of novel lab-on-chip miniaturized tools for biological and medical applications. In this paper we demonstrate how magnetic domain walls generated in micro- and nano-structures fabricated on a chip surface can be used to handle single yeast cells labeled with magnetic beads. In detail, first we show that the proposed approach maintains the microorganism viable, as proven by monitoring the division of labeled yeast cells trapped by domain walls over 16 hours. Moreover, we demonstrate the controlled transport and release of individual yeast cells via displacement and annihilation of individual domain walls in micro- and nano-sized magnetic structures. These results pave the way to the implementation of magnetic devices based on domain walls technology in lab-on-chip systems devoted to accurate individual cell trapping and manipulation.

Microwave Radiometer Technology Acceleration Mission (MiRaTA): Advancing Weather Remote Sensing with Nanosatellites

NASA Astrophysics Data System (ADS)

Cahoy, K.; Blackwell, W. J.; Bishop, R. L.; Erickson, N.; Fish, C. S.; Neilsen, T. L.; Stromberg, E. M.; Bardeen, J.; Dave, P.; Marinan, A.; Marlow, W.; Kingsbury, R.; Kennedy, A.; Byrne, J. M.; Peters, E.; Allen, G.; Burianek, D.; Busse, F.; Elliott, D.; Galbraith, C.; Leslie, V. V.; Osaretin, I.; Shields, M.; Thompson, E.; Toher, D.; DiLiberto, M.

2014-12-01

The Microwave Radiometer Technology Acceleration (MiRaTA) is a 3U CubeSat mission sponsored by the NASA Earth Science Technology Office (ESTO). Microwave radiometer measurements and GPS radio occultation (GPSRO) measurements of all-weather temperature and humidity provide key contributions toward improved weather forecasting. The MiRaTA mission will validate new technologies in both passive microwave radiometry and GPS radio occultation: (1) new ultra-compact and low-power technology for multi-channel and multi-band passive microwave radiometers, and (2) new GPS receiver and patch antenna array technology for GPS radio occultation retrieval of both temperature-pressure profiles in the atmosphere and electron density profiles in the ionosphere. In addition, MiRaTA will test (3) a new approach to spaceborne microwave radiometer calibration using adjacent GPSRO measurements. The radiometer measurement quality can be substantially improved relative to present systems through the use of proximal GPSRO measurements as a calibration standard for radiometric observations, reducing and perhaps eliminating the need for costly and complex internal calibration targets. MiRaTA will execute occasional pitch-up maneuvers so that the radiometer and GPSRO observations sound overlapping volumes of atmosphere through the Earth's limb. To validate system performance, observations from both microwave radiometer (MWR) and GPSRO instruments will be compared to radiosondes, global high-resolution analysis fields, other satellite observations, and to each other using radiative transfer models. Both the radiometer and GPSRO payloads, currently at TRL5 but to be advanced to TRL7 at mission conclusion, can be accommodated in a single 3U CubeSat. The current plan is to launch from an International Space Station (ISS) orbit at ~400 km altitude and 52° inclination for low-cost validation over a ~90-day mission to fly in 2016. MiRaTA will demonstrate high fidelity, well-calibrated radiometric

Investigation on Wall Panel Sandwiched With Lightweight Concrete

NASA Astrophysics Data System (ADS)

Lakshmikandhan, K. N.; Harshavardhan, B. S.; Prabakar, J.; Saibabu, S.

2017-08-01

The rapid population growth and urbanization have made a massive demand for the shelter and construction materials. Masonry walls are the major component in the housing sector and it has brittle characteristics and exhibit poor performance against the uncertain loads. Further, the structure requires heavier sections for carrying the dead weight of masonry walls. The present investigations are carried out to develop a simple, lightweight and cost effective technology for replacing the existing wall systems. The lightweight concrete is developed for the construction of sandwich wall panel. The EPS (Expanded Polystyrene) beads of 3 mm diameter size are mixed with concrete and developed a lightweight concrete with a density 9 kN/m3. The lightweight sandwich panel is cast with a lightweight concrete inner core and ferrocement outer skins. This lightweight wall panel is tested for in-plane compression loading. A nonlinear finite element analysis with damaged plasticity model is carried out with both material and geometrical nonlinearities. The experimental and analytical results were compared. The finite element study predicted the ultimate load carrying capacity of the sandwich panel with reasonable accuracy. The present study showed that the lightweight concrete is well suitable for the lightweight sandwich wall panels.

Educating and Training Accelerator Scientists and Technologists for Tomorrow

NASA Astrophysics Data System (ADS)

Barletta, William; Chattopadhyay, Swapan; Seryi, Andrei

2012-01-01

Accelerator science and technology is inherently an integrative discipline that combines aspects of physics, computational science, electrical and mechanical engineering. As few universities offer full academic programs, the education of accelerator physicists and engineers for the future has primarily relied on a combination of on-the-job training supplemented with intensive courses at regional accelerator schools. This article describes the approaches being used to satisfy the educational curiosity of a growing number of interested physicists and engineers.

Educating and Training Accelerator Scientists and Technologists for Tomorrow

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

Barletta, William A.; Chattopadhyay, Swapan; Seryi, Andrei

2012-07-01

Accelerator science and technology is inherently an integrative discipline that combines aspects of physics, computational science, electrical and mechanical engineering. As few universities offer full academic programs, the education of accelerator physicists and engineers for the future has primarily relied on a combination of on-the-job training supplemented with intense courses at regional accelerator schools. This paper describes the approaches being used to satisfy the educational interests of a growing number of interested physicists and engineers.

A wall interference assessment/correction interface measurement system for the NASA/ARC 12-ft PWT

NASA Technical Reports Server (NTRS)

1989-01-01

Development of complex air vehicle configurations is placing increasing demands on wind tunnel testing capabilities. A major area of concern is wall induced interference. Recent developments in wall interference technology provide a means for assessing and correcting for the wall induced interference using information contained in the distribution of flow variables measured at, or near, the wall. The restoration of the NASA-ARC 12-ft pressure wind tunnel (PWT) provides an opportunity to incorporate a measurement system with which wall interference assessment/correction (WIAC) technology can be applied. In this first phase of the development of a WIAC system for the PWT, the design criteria for the placement and the geometry of wall static pressure orifices were determined with a three step approach. First, the operational environment of the PWT was analyzed as to the requirements for the WIAC system. Second, appropriate wall interference theories were evaluated against the requirements determined from the operational environment. Third, the flow about representative models in the PWT was calculated and, specifically, the pressure signatures at the location of the test section wall were obtained. The number of discrete pressure measurements and their locations were determined by curve fitting the pressure distribution through the discrete measurements and evaluating the resulting error.

Technology evaluation of man-rated acceleration test equipment for vestibular research

NASA Technical Reports Server (NTRS)

Taback, I.; Kenimer, R. L.; Butterfield, A. J.

1983-01-01

The considerations for eliminating acceleration noise cues in horizontal, linear, cyclic-motion sleds intended for both ground and shuttle-flight applications are addressed. the principal concerns are the acceleration transients associated with change in direction-of-motion for the carriage. The study presents a design limit for acceleration cues or transients based upon published measurements for thresholds of human perception to linear cyclic motion. The sources and levels for motion transients are presented based upon measurements obtained from existing sled systems. The approaches to a noise-free system recommends the use of air bearings for the carriage support and moving-coil linear induction motors operating at low frequency as the drive system. Metal belts running on air bearing pulleys provide an alternate approach to the driving system. The appendix presents a discussion of alternate testing techniques intended to provide preliminary type data by means of pendulums, linear motion devices and commercial air bearing tables.

Andreas Acrivos Dissertation Award Talk: Modeling drag forces and velocity fluctuations in wall-bounded flows at high Reynolds numbers

NASA Astrophysics Data System (ADS)

Yang, Xiang

2017-11-01

The sizes of fluid motions in wall-bounded flows scale approximately as their distances from the wall. At high Reynolds numbers, resolving near-wall, small-scale, yet momentum-transferring eddies are computationally intensive, and to alleviate the strict near-wall grid resolution requirement, a wall model is usually used. The wall model of interest here is the integral wall model. This model parameterizes the near-wall sub-grid velocity profile as being comprised of a linear inner-layer and a logarithmic meso-layer with one additional term that accounts for the effects of flow acceleration, pressure gradients etc. We use the integral wall model for wall-modeled large-eddy simulations (WMLES) of turbulent boundary layers over rough walls. The effects of rough-wall topology on drag forces are investigated. A rough-wall model is then developed based on considerations of such effects, which are now known as mutual sheltering among roughness elements. Last, we discuss briefly a new interpretation of the Townsend attached eddy hypothesis-the hierarchical random additive process model (HRAP). The analogy between the energy cascade and the momentum cascade is mathematically formal as HRAP follows the multi-fractal formulism, which was extensively used for the energy cascade.

EDITORIAL: Laser and plasma accelerators Laser and plasma accelerators

NASA Astrophysics Data System (ADS)

Bingham, Robert

2009-02-01

This special issue on laser and plasma accelerators illustrates the rapid advancement and diverse applications of laser and plasma accelerators. Plasma is an attractive medium for particle acceleration because of the high electric field it can sustain, with studies of acceleration processes remaining one of the most important areas of research in both laboratory and astrophysical plasmas. The rapid advance in laser and accelerator technology has led to the development of terawatt and petawatt laser systems with ultra-high intensities and short sub-picosecond pulses, which are used to generate wakefields in plasma. Recent successes include the demonstration by several groups in 2004 of quasi-monoenergetic electron beams by wakefields in the bubble regime with the GeV energy barrier being reached in 2006, and the energy doubling of the SLAC high-energy electron beam from 42 to 85 GeV. The electron beams generated by the laser plasma driven wakefields have good spatial quality with energies ranging from MeV to GeV. A unique feature is that they are ultra-short bunches with simulations showing that they can be as short as a few femtoseconds with low-energy spread, making these beams ideal for a variety of applications ranging from novel high-brightness radiation sources for medicine, material science and ultrafast time-resolved radiobiology or chemistry. Laser driven ion acceleration experiments have also made significant advances over the last few years with applications in laser fusion, nuclear physics and medicine. Attention is focused on the possibility of producing quasi-mono-energetic ions with energies ranging from hundreds of MeV to GeV per nucleon. New acceleration mechanisms are being studied, including ion acceleration from ultra-thin foils and direct laser acceleration. The application of wakefields or beat waves in other areas of science such as astrophysics and particle physics is beginning to take off, such as the study of cosmic accelerators considered

Evaluation of optical data gained by ARAMIS-measurement of abdominal wall movements for an anisotropic pattern design of stress-adapted hernia meshes produced by embroidery technology

NASA Astrophysics Data System (ADS)

Breier, A.; Bittrich, L.; Hahn, J.; Spickenheuer, A.

2017-10-01

For the sustainable repair of abdominal wall hernia the application of hernia meshes is required. One reason for the relapse of hernia after surgery is seen in an inadequate adaption of the mechanical properties of the mesh to the movements of the abdominal wall. Differences in the stiffness of the mesh and the abdominal tissue cause tension, friction and stress resulting in a deficient tissue response and subsequently in a recurrence of a hernia, preferentially in the marginal area of the mesh. Embroidery technology enables a targeted influence on the mechanical properties of the generated textile structure by a directed thread deposition. Textile parameters like stitch density, alignment and angle can be changed easily and locally in the embroidery pattern to generate a space-resolved mesh with mechanical properties adapted to the requirement of the surrounding tissue. To determine those requirements the movements of the abdominal wall and the resulting distortions need to be known. This study was conducted to gain optical data of the abdominal wall movements by non-invasive ARAMIS-measurement on 39 test persons to estimate direction and value of the major strains.

Radiobiological effectiveness of laser accelerated electrons in comparison to electron beams from a conventional linear accelerator.

PubMed

Laschinsky, Lydia; Baumann, Michael; Beyreuther, Elke; Enghardt, Wolfgang; Kaluza, Malte; Karsch, Leonhard; Lessmann, Elisabeth; Naumburger, Doreen; Nicolai, Maria; Richter, Christian; Sauerbrey, Roland; Schlenvoigt, Hans-Peter; Pawelke, Jörg

2012-01-01

The notable progress in laser particle acceleration technology promises potential medical application in cancer therapy through compact and cost effective laser devices that are suitable for already existing clinics. Previously, consequences on the radiobiological response by laser driven particle beams characterised by an ultra high peak dose rate have to be investigated. Therefore, tumour and non-malignant cells were irradiated with pulsed laser accelerated electrons at the JETI facility for the comparison with continuous electrons of a conventional therapy LINAC. Dose response curves were measured for the biological endpoints clonogenic survival and residual DNA double strand breaks. The overall results show no significant differences in radiobiological response for in vitro cell experiments between laser accelerated pulsed and clinical used electron beams. These first systematic in vitro cell response studies with precise dosimetry to laser driven electron beams represent a first step toward the long term aim of the application of laser accelerated particles in radiotherapy.

Peculiarities of non-autoclaved lime wall materials production using clays

NASA Astrophysics Data System (ADS)

Volodchenko, A. A.; Lesovik, V. S.; Cherepanova, I. A.; Volodchenko, A. N.; Zagorodnjuk, L. H.; Elistratkin, M. Y.

2018-03-01

At present, the development and implementation of energy saving technologies for building materials production, which correspond to modern trends of «green» technologies, become ever more popular. One of the most widely spread wall materials today is a lime brick and stones. The primary raw goods used in production of such materials are quarziferous rocks. However, they have some disadvantages, including low strength index at the intermediate phase of their production, especially in case with a raw brick, which is an issue in the production of high-hollow goods due to low strength index of raw materials and the nonoptimal matrix structure. The conducted experiments confirmed the possibility to control structurization of building composites due to application of nonconventional argillous raw materials. Besides, the material and mineral composition of nonconventional clay rocks ensures the optimal microstructure thus providing for the production of efficient wall building materials via energy saving technology.

Acceleration of robust "biotube" vascular graft fabrication by in-body tissue architecture technology using a novel eosin Y-releasing mold.

PubMed

Nakayama, Yasuhide; Tsujinaka, Takahiro

2014-02-01

A novel eosin Y-releasing mold was designed to accelerate the fabrication of in vivo tissue engineered autologous vascular prosthetic tissues, called the "biotubes." The mold was prepared by addition of an aqueous solution of eosin Y (1∼6 w/v%) to the agar gel (0.3%), which was attached to the luminal surface of the microporous acrylate tube (diameter, 5 mm; length, 28 mm; pore size, 0.5 mmϕ). The eosin Y release period was controlled by the number of pores (3∼160). On embedding the molds into dorsal, subcutaneous pouches of rats for 1 week, completely encapsulated biotubes, mainly consisting of collagen, with thick walls (418.2 ± 173.4 μm) and robust mechanical properties (elastic modulus, 956.2 ± 196.5 kPa; burst pressure 5850 ± 2383 mmHg) were formed. These values were, respectively, more than 4.3, 3.8, and 5.6 times greater than the corresponding controls (acrylate rods). The high elastic modulus of the biotubes was obtained even with a small number of micropores (3), and a low concentration of eosin Y (1%) within a very short embedding period (5 days), irrespective of rat weights. This innovative method for rapid production of vascular grafts with thick walls and robust mechanical properties may be adaptable for the sub-emergency clinical use of biotubes in regenerative medicine. Copyright © 2013 Wiley Periodicals, Inc.

[Shielding design and detection of neutrons from medical and industrial electron accelerators--simple method of design calculation for neutron shielding].

PubMed

Nakamura, T; Uwamino, Y

1986-02-01

The neutron leakage from medical and industrial electron accelerators has become an important problem and its detection and shielding is being performed in their facilities. This study provides a new simple method of design calculation for neutron shielding of those electron accelerator facilities by dividing into the following five categories; neutron dose distribution in the accelerator room, neutron attenuation through the wall and the door in the accelerator room, neutron and secondary photon dose distributions in the maze, neutron and secondary photon attenuation through the door at the end of the maze, neutron leakage outside the facility-skyshine.

Inside-the-wall detection of objects with low metal content using the GPR sensor: effects of different wall structures on the detection performance

NASA Astrophysics Data System (ADS)

Dogan, Mesut; Yesilyurt, Omer; Turhan-Sayan, Gonul

2018-04-01

Ground penetrating radar (GPR) is an ultra-wideband electromagnetic sensor used not only for subsurface sensing but also for the detection of objects which may be hidden behind a wall or inserted within the wall. Such applications of the GPR technology are used in both military and civilian operations such as mine or IED (improvised explosive device) detection, rescue missions after earthquakes and investigation of archeological sites. Detection of concealed objects with low metal content is known to be a challenging problem in general. Use of A-scan, B-scan and C-scan GPR data in combination provides valuable information for target recognition in such applications. In this paper, we study the problem of target detection for potentially explosive objects embedded inside a wall. GPR data is numerically simulated by using an FDTD-based numerical computation tool when dielectric targets and targets with low metal content are inserted into different types of walls. A small size plastic bottle filled with trinitrotoluene (TNT) is used as the target with and without a metal fuse in it. The targets are buried into two different types of wall; a homogeneous brick wall and an inhomogeneous wall constructed by bricks having periodically located air holes in it. Effects of using an inhomogeneous wall structure with internal boundaries are investigated as a challenging scenario, paying special attention to preprocessing.

The logarithmic and power law behaviors of the accelerating, turbulent thermal boundary layer

NASA Astrophysics Data System (ADS)

Castillo, Luciano; Hussain, Fazle

2017-02-01

Direct numerical simulation of spatially evolving thermal turbulent boundary layers with strong favorable pressure gradient (FPG) shows that the thermal fluctuation intensity, θ' + and the Reynolds shear stress, u'v'¯+ exhibit a logarithmic behavior spanning the meso-layer (e.g., 50 ≤y+≤170 ). However, the mean thermal profile is not logarithmic even in the zero pressure gradient (ZPG) region; instead, it follows a power law. The maxima of u' 2 ¯+ and v'θ'¯+ change little with the strength of acceleration, while v'+, w'+, and u'v'¯+ continue to decay in the flow direction. Furthermore, θ'+ and u'θ'¯+ surprisingly experience changes from constants in ZPG to sharp rises in the FPG region. Such behavior appears to be due to squashing of the streaks which decreases the streak flank angle below the critical value for "transient growth" generation of streamwise vortices, shutting down production [W. Schoppa and F. Hussain, "Coherent structure generation near-wall turbulence," J. Fluid Mech. 453, 57-108 (2002)]. The streamwise vortices near the wall, although shrink because of stretching, simultaneously, also become weaker as the structures are progressively pushed farther down to the more viscous region near the wall. While the vortical structures decay rapidly in accelerating flows, the thermal field does not—nullifying the myth that both the thermal and velocity fields are similar.

Accelerator boom hones China's engineering expertise

NASA Astrophysics Data System (ADS)

Normile, Dennis

2018-02-01

In raising the curtain on the China Spallation Neutron Source, China has joined just four other nations in having mastered the technology of accelerating and controlling beams of protons. The $277 million facility, set to open to users this spring in Dongguan, is expected to yield big dividends in materials science, chemistry, and biology. More world class machines are on the way, as China this year starts construction on four other major accelerator facilities. The building boom is prompting a scramble to find enough engineers and technicians to finish the projects. But if they all come off as planned, the facilities would position China to tackle the next global megaproject: a giant accelerator that would pick up where Europe's Large Hadron Collider leaves off.

Impact accelerations

NASA Technical Reports Server (NTRS)

Vongierke, H. E.; Brinkley, J. W.

1975-01-01

The degree to which impact acceleration is an important factor in space flight environments depends primarily upon the technology of capsule landing deceleration and the weight permissible for the associated hardware: parachutes or deceleration rockets, inflatable air bags, or other impact attenuation systems. The problem most specific to space medicine is the potential change of impact tolerance due to reduced bone mass and muscle strength caused by prolonged weightlessness and physical inactivity. Impact hazards, tolerance limits, and human impact tolerance related to space missions are described.

Visual evidence of suppressing the ion and electron energy loss on the wall in Hall thrusters

NASA Astrophysics Data System (ADS)

Ding, Yongjie; Peng, Wuji; Sun, Hezhi; Wei, Liqiu; Zeng, Ming; Wang, Fufeng; Yu, Daren

2017-03-01

A method of pushing down magnetic field with two permanent magnetic rings is proposed in this paper. It can realize ionization in a channel and acceleration outside the channel. The wall will only suffer from the bombardment of low-energy ions and electrons, which can effectively reduce channel erosion and extend the operational lifetime of thrusters. Furthermore, there is no additional power consumption of coils, which improves the efficiency of systems. We show here the newly developed 200 W no wall-loss Hall thruster (NWLHT-200) that applies the method of pushing down magnetic field with two permanent magnetic rings; the visual evidence we obtained preliminarily confirms the feasibility that the proposed method can realize discharge without wall energy loss or erosion of Hall thrusters.

Control of Mechanical Stresses of High Pressure Container Walls by Magnetoelastic Method

NASA Astrophysics Data System (ADS)

Kulak, S. M.; Novikov, V. F.; Baranov, A. V.

2016-10-01

Deformations of the walls of pressure vessels arising in the process of testing and operation, as well as reduce their thickness due to corrosion, to create the prerequisites for the growth of mechanical stresses which accelerating the processes of strain aging, embrittlement of the material and reducing its fatigue properties. This article is devoted to researches of the magnetoelastic demagnetization in the wall of steel vessel of loading by internal pressure. It is established that the increasing pressure on the vessel wall is accompanied by a monotonic decrease in the intensity of the magnetic stray field of local magnetization of steel. It is shown that a magnetic stray field of local magnetization of the wall of steel vessel is non-uniform due to differences in structure and stresses. It is proposed to use the obtained results to control the stress state of vessels, experiencing multi-axial loads generated by internal pressure (pipelines, oil tanks, etc.) The method of magnetoelastic of the demagnetization of the steel has a high sensitivity to mechanical stress, the simplicity of implementation and expressiveness compared to the strain gauge and method of coercive force.

The influence of geopolitical change on the well-being of a population: the Berlin Wall.

PubMed

Héon-Klin, V; Sieber, E; Huebner, J; Fullilove, M T

2001-03-01

Social cohesion is recognized as a fundamental condition for healthy populations, but social cohesion itself arises from political unity. The history of the Berlin Wall provides a unique opportunity to examine the effects of partition on social cohesion and, by inference, on health. This ethnographic study consisted of examination of the territory formerly occupied by the Wall, formal and informal interviews with Berlin residents, and collection of cultural documents related to the Wall. Transcripts, field notes, and documents were examined by means of a keyword-in-context analysis. The separation of Berlin into 2 parts was a traumatic experience for the city's residents. After partition, East and West Germany had divergent social, cultural, and political experiences and gradually grew apart. The demolition of the Wall--the symbol and the instrument of partition--makes possible but does not ensure the reintegration of 2 populations that were separated for 40 years. The evolution of a new common culture might be accelerated by active attempts at cultural and social exchange.

Highly efficient nonrigid motion‐corrected 3D whole‐heart coronary vessel wall imaging

PubMed Central

Atkinson, David; Henningsson, Markus; Botnar, Rene M.; Prieto, Claudia

2016-01-01

Purpose To develop a respiratory motion correction framework to accelerate free‐breathing three‐dimensional (3D) whole‐heart coronary lumen and coronary vessel wall MRI. Methods We developed a 3D flow‐independent approach for vessel wall imaging based on the subtraction of data with and without T2‐preparation prepulses acquired interleaved with image navigators. The proposed method corrects both datasets to the same respiratory position using beat‐to‐beat translation and bin‐to‐bin nonrigid corrections, producing coregistered, motion‐corrected coronary lumen and coronary vessel wall images. The proposed method was studied in 10 healthy subjects and was compared with beat‐to‐beat translational correction (TC) and no motion correction for the left and right coronary arteries. Additionally, the coronary lumen images were compared with a 6‐mm diaphragmatic navigator gated and tracked scan. Results No significant differences (P > 0.01) were found between the proposed method and the gated and tracked scan for coronary lumen, despite an average improvement in scan efficiency to 96% from 59%. Significant differences (P < 0.01) were found in right coronary artery vessel wall thickness, right coronary artery vessel wall sharpness, and vessel wall visual score between the proposed method and TC. Conclusion The feasibility of a highly efficient motion correction framework for simultaneous whole‐heart coronary lumen and vessel wall has been demonstrated. Magn Reson Med 77:1894–1908, 2017. © 2016 International Society for Magnetic Resonance in Medicine PMID:27221073

EuCARD 2010: European coordination of accelerator research and development

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.

2010-09-01

Accelerators are basic tools of the experimental physics of elementary particles, nuclear physics, light sources of the fourth generation. They are also used in myriad other applications in research, industry and medicine. For example, there are intensely developed transmutation techniques for nuclear waste from nuclear power and atomic industries. The European Union invests in the development of accelerator infrastructures inside the framework programs to build the European Research Area. The aim is to build new accelerator research infrastructures, develop the existing ones, and generally make the infrastructures more available to competent users. The paper summarizes the first year of activities of the EU FP7 Project Capacities EuCARD -European Coordination of Accelerator R&D. EuCARD is a common venture of 37 European Accelerator Laboratories, Institutes, Universities and Industrial Partners involved in accelerator sciences and technologies. The project, initiated by ESGARD, is an Integrating Activity co-funded by the European Commission under Framework Program 7 - Capacities for a duration of four years, starting April 1st, 2009. Several teams from this country participate actively in this project. The contribution from Polish research teams concerns: photonic and electronic measurement - control systems, RF-gun co-design, thin-film superconducting technology, superconducting transport infrastructures, photon and particle beam measurements and control.

Microwave a.c. conductivity of domain walls in ferroelectric thin films

DOE PAGES

Tselev, Alexander; Yu, Pu; Cao, Ye; ...

2016-05-31

Ferroelectric domain walls are of great interest as elementary building blocks for future electronic devices due to their intrinsic few-nanometre width, multifunctional properties and field-controlled topology. To realize the electronic functions, domain walls are required to be electrically conducting and addressable non-destructively. However, these properties have been elusive because conducting walls have to be electrically charged, which makes them unstable and uncommon in ferroelectric materials. Here we reveal that spontaneous and recorded domain walls in thin films of lead zirconate and bismuth ferrite exhibit large conductance at microwave frequencies despite being insulating at d.c. We explain this effect by morphologicalmore » roughening of the walls and local charges induced by disorder with the overall charge neutrality. a.c. conduction is immune to large contact resistance enabling completely non-destructive walls read-out. Finally, this demonstrates a technological potential for harnessing a.c. conduction for oxide electronics and other materials with poor d.c. conduction, particularly at the nanoscale.« less

Microwave a.c. conductivity of domain walls in ferroelectric thin films

PubMed Central

Tselev, Alexander; Yu, Pu; Cao, Ye; Dedon, Liv R.; Martin, Lane W.; Kalinin, Sergei V.; Maksymovych, Petro

2016-01-01

Ferroelectric domain walls are of great interest as elementary building blocks for future electronic devices due to their intrinsic few-nanometre width, multifunctional properties and field-controlled topology. To realize the electronic functions, domain walls are required to be electrically conducting and addressable non-destructively. However, these properties have been elusive because conducting walls have to be electrically charged, which makes them unstable and uncommon in ferroelectric materials. Here we reveal that spontaneous and recorded domain walls in thin films of lead zirconate and bismuth ferrite exhibit large conductance at microwave frequencies despite being insulating at d.c. We explain this effect by morphological roughening of the walls and local charges induced by disorder with the overall charge neutrality. a.c. conduction is immune to large contact resistance enabling completely non-destructive walls read-out. This demonstrates a technological potential for harnessing a.c. conduction for oxide electronics and other materials with poor d.c. conduction, particularly at the nanoscale. PMID:27240997

PREFACE: Domain wall dynamics in nanostructures Domain wall dynamics in nanostructures

NASA Astrophysics Data System (ADS)

Marrows, C. H.; Meier, G.

2012-01-01

Domain structures in magnetic materials are ubiquitous and have been studied for decades. The walls that separate them are topological defects in the magnetic order parameter and have a wide variety of complex forms. In general, their investigation is difficult in bulk materials since only the domain structure on the surface of a specimen is visible. Cutting the sample to reveal the interior causes a rearrangement of the domains into a new form. As with many other areas of magnetism, the study of domain wall physics has been revitalised by the advent of nanotechnology. The ability to fabricate nanoscale structures has permitted the formation of simplified and controlled domain patterns; the development of advanced microscopy methods has permitted them to be imaged and then modelled; subjecting them to ultrashort field and current pulses has permitted their dynamics to be explored. The latest results from all of these advances are described in this special issue. Not only has this led to results of great scientific beauty, but also to concepts of great applicability to future information technologies. In this issue the reader will find the latest results for these domain wall dynamics and the high-speed processes of topological structures such as domain walls and magnetic vortices. These dynamics can be driven by the application of magnetic fields, or by flowing currents through spintronic devices using the novel physics of spin-transfer torque. This complexity has been studied using a wide variety of experimental techniques at the edge of the spatial and temporal resolution currently available, and can be described using sophisticated analytical theory and computational modelling. As a result, the dynamics can be engineered to give rise to finely controlled memory and logic devices with new functionality. Moreover, the field is moving to study not only the conventional transition metal ferromagnets, but also complex heterostructures, novel magnets and even other

Mathematical Model of Stress-Strain State of Curved Tube of Non-Circular Cross-Section with Account of Technological Wall Thickness Variation

NASA Astrophysics Data System (ADS)

Pirogov, S. P.; Ustinov, N. N.; Smolin, N. I.

2018-05-01

A mathematical model of the stress-strain state of a curved tube of a non-circular cross-section is presented, taking into account the technological wall thickness variation. On the basis of the semi-membrane shell theory, a system of linear differential equations describing the deformation of a tube under the effect of pressure is obtained. To solve the boundary value problem, the method of shooting is applied. The adequacy of the proposed mathematical model is verified by comparison with the experimental data and the results of the calculation of tubes by the energy method.

Neural Networks for Modeling and Control of Particle Accelerators

NASA Astrophysics Data System (ADS)

Edelen, A. L.; Biedron, S. G.; Chase, B. E.; Edstrom, D.; Milton, S. V.; Stabile, P.

2016-04-01

Particle accelerators are host to myriad nonlinear and complex physical phenomena. They often involve a multitude of interacting systems, are subject to tight performance demands, and should be able to run for extended periods of time with minimal interruptions. Often times, traditional control techniques cannot fully meet these requirements. One promising avenue is to introduce machine learning and sophisticated control techniques inspired by artificial intelligence, particularly in light of recent theoretical and practical advances in these fields. Within machine learning and artificial intelligence, neural networks are particularly well-suited to modeling, control, and diagnostic analysis of complex, nonlinear, and time-varying systems, as well as systems with large parameter spaces. Consequently, the use of neural network-based modeling and control techniques could be of significant benefit to particle accelerators. For the same reasons, particle accelerators are also ideal test-beds for these techniques. Many early attempts to apply neural networks to particle accelerators yielded mixed results due to the relative immaturity of the technology for such tasks. The purpose of this paper is to re-introduce neural networks to the particle accelerator community and report on some work in neural network control that is being conducted as part of a dedicated collaboration between Fermilab and Colorado State University (CSU). We describe some of the challenges of particle accelerator control, highlight recent advances in neural network techniques, discuss some promising avenues for incorporating neural networks into particle accelerator control systems, and describe a neural network-based control system that is being developed for resonance control of an RF electron gun at the Fermilab Accelerator Science and Technology (FAST) facility, including initial experimental results from a benchmark controller.

Accelerator Generation and Thermal Separation (AGATS) of Technetium-99m

ScienceCinema

Grover, Blaine

2018-05-01

Accelerator Generation and Thermal Separation (AGATS) of Technetium-99m is a linear electron accelerator-based technology for producing medical imaging radioisotopes from a separation process that heats, vaporizes and condenses the desired radioisotope. You can learn more about INL's education programs at http://www.facebook.com/idahonationallaboratory.

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

Accelerated horizons and Planck-scale kinematics

NASA Astrophysics Data System (ADS)

Arzano, Michele; Laudonio, Matteo

2018-04-01

We extend the concept of accelerated horizons to the framework of deformed relativistic kinematics at the Planck scale. We show that the nontrivial effects due to symmetry deformation manifest in a finite blueshift for field modes as measured by a Rindler observer approaching the horizon. We investigate whether, at a field theoretic level, this effect could manifest in the possibility of a finite horizon contribution to the entropy, a sort of covariant brick wall. In the specific model of symmetry deformation considered, it will turn out that a nondiverging density of modes close to the horizon can be achieved only by introducing a momentum space measure which violates Lorentz invariance.

EFFECTOF ISOLATION WALL USING SCRAP TIRE ON GROUND VIBRATION REDUCTION

NASA Astrophysics Data System (ADS)

Kashimoto, Takahiko; Kashimoto, Yusuke; Hayakawa, Kiyoshi; Matsui, Tamotsu; Fujimoto, Hiroaki

Some countermeasure methods against the environmental ground vibration caused by some traffic vibrations have been proposed so far. The authors have developed a new type ground vibration isolation wall using scrap tire, and evaluated its effectiveness on the ground vibration reduction by full scale field tests. In this paper, the authors discussed and examined the effectiveness of the developed countermeasure method by two field tests. The one concerns on the effect of scrap tire as soft material of vibration isolation wall, and the other on the effect of the developed countermeasure method practically applied in a residential area close to monorail traffic. As the results, it was elucidated that the ground vibration of 2-3 dB was reduced in case of two times volume of the soft material, the conversion ratio of the vibration energy of the soft material to the kinetic energy was higher than that of the core material of PHC pile, the vibration acceleration of 0.19 - 1.26 gal was reduced by the developed countermeasure method in case of the monorail traffic, and the vibration reduction measured behind the isolation wall agreed well with the proposed theoretical value, together with confirming the effectiveness of the ground vibration isolation wall using scrap tire as the countermeasure method against the environmental ground vibration.

Experimental Results from a Resonant Dielectric Laser Accelerator

NASA Astrophysics Data System (ADS)

Yoder, Rodney; McNeur, Joshua; Sozer, Esin; Travish, Gil; Hazra, Kiran Shankar; Matthews, Brian; England, Joel; Peralta, Edgar; Wu, Ziran

2015-04-01

Laser-powered accelerators have the potential to operate with very large accelerating gradients (~ GV/m) and represent a path toward extremely compact colliders and accelerator technology. Optical-scale laser-powered devices based on field-shaping structures (known as dielectric laser accelerators, or DLAs) have been described and demonstrated recently. Here we report on the first experimental results from the Micro-Accelerator Platform (MAP), a DLA based on a slab-symmetric resonant optical-scale structure. As a resonant (rather than near-field) device, the MAP is distinct from other DLAs. Its cavity resonance enhances its accelerating field relative to the incoming laser fields, which are coupled efficiently through a diffractive optic on the upper face of the device. The MAP demonstrated modest accelerating gradients in recent experiments, in which it was powered by a Ti:Sapphire laser well below its breakdown limit. More detailed results and some implications for future developments will be discussed. Supported in part by the U.S. Defense Threat Reduction Agency (UCLA); U.S. Dept of Energy (SLAC); and DARPA (SLAC).

Geometric effects resulting from the asymmetry of dipping fault: Hanging wall/ footwall effects

NASA Astrophysics Data System (ADS)

Wang, Dong; Xie, Li-Li; Hu, Jin-Jun

2008-05-01

Root-mean-square distance D rms with characteristic of weighted-average is introduced in this article firstly. D rms can be used to capture the general proximity of a site to a dipping fault plane comparing with the rupture distance D rup and the seismogenic distance D seis. Then, using D rup, D seis and D rms, the hanging wall/footwall effects on the peak ground acceleration (PGA) during the 1999 Chi-Chi earthquake are evaluated by regression analysis. The logarithm residual shows that the PGA on hanging wall is much greater than that on footwall at the same D rup or D seis when the D rup or D seis is used as site-to-source distance measure. In contrast, there is no significant difference between the PGA on hanging wall and that on footwall at the same D rms when D rms is used. This result confirms that the hanging wall/footwall effect is mainly a geometric effect caused by the asymmetry of dipping fault. Therefore, the hanging wall/footwall effect on the near-fault ground motions can be ignored in the future attenuation analysis if the root-mean-square distance D rms is used as the site-to-source distance measure.

Vibration characteristics of walls and a plate glass window representative of those of a wood-frame house

NASA Technical Reports Server (NTRS)

Carden, H. D.

1979-01-01

Mechanical excitation was used, and measurements of acceleration response, natural frequencies, and nodal patterns were performed. Results indicate that the wall sections and the complete wall did not act as a unit in responding to sinusoidal vibration inputs. Calculated frequencies of the components that account for this independent behavior of the studs and face sheets agreed resonably well with experimental frequencies. Experimental vibrations of the plate glass window agreed with the calculated behavior, and responses of the window exposed to airplane flyover noise were readily correlated with the test results.

Accelerators for Cancer Therapy

DOE R&D Accomplishments Database

Lennox, Arlene J.

2000-05-30

The vast majority of radiation treatments for cancerous tumors are given using electron linacs that provide both electrons and photons at several energies. Design and construction of these linacs are based on mature technology that is rapidly becoming more and more standardized and sophisticated. The use of hadrons such as neutrons, protons, alphas, or carbon, oxygen and neon ions is relatively new. Accelerators for hadron therapy are far from standardized, but the use of hadron therapy as an alternative to conventional radiation has led to significant improvements and refinements in conventional treatment techniques. This paper presents the rationale for radiation therapy, describes the accelerators used in conventional and hadron therapy, and outlines the issues that must still be resolved in the emerging field of hadron therapy.

15 Years of R&D on high field accelerator magnets at FNAL

DOE PAGES

Barzi, Emanuela; Zlobin, Alexander V.

2016-07-01

The High Field Magnet (HFM) Program at Fermi National Accelerator Laboratory (FNAL) has been developing Nb 3Sn superconducting magnets, materials and technologies for present and future particle accelerators since the late 1990s. This paper summarizes the main results of the Nb 3Sn accelerator magnet and superconductor R&D at FNAL and outlines the Program next steps.

Seismic analysis for translational failure of landfills with retaining walls.

PubMed

Feng, Shi-Jin; Gao, Li-Ya

2010-11-01

In the seismic impact zone, seismic force can be a major triggering mechanism for translational failures of landfills. The scope of this paper is to develop a three-part wedge method for seismic analysis of translational failures of landfills with retaining walls. The approximate solution of the factor of safety can be calculated. Unlike previous conventional limit equilibrium methods, the new method is capable of revealing the effects of both the solid waste shear strength and the retaining wall on the translational failures of landfills during earthquake. Parameter studies of the developed method show that the factor of safety decreases with the increase of the seismic coefficient, while it increases quickly with the increase of the minimum friction angle beneath waste mass for various horizontal seismic coefficients. Increasing the minimum friction angle beneath the waste mass appears to be more effective than any other parameters for increasing the factor of safety under the considered condition. Thus, selecting liner materials with higher friction angle will considerably reduce the potential for translational failures of landfills during earthquake. The factor of safety gradually increases with the increase of the height of retaining wall for various horizontal seismic coefficients. A higher retaining wall is beneficial to the seismic stability of the landfill. Simply ignoring the retaining wall will lead to serious underestimation of the factor of safety. Besides, the approximate solution of the yield acceleration coefficient of the landfill is also presented based on the calculated method. Copyright © 2010 Elsevier Ltd. All rights reserved.

78 FR 65747 - Notice of Funding Availability for Accelerated Innovation Deployment Demonstration

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-01

... Funding Availability for Accelerated Innovation Deployment Demonstration AGENCY: Federal Highway... comments. SUMMARY: This notice announces the availability of funding for Accelerated Innovation Deployment (AID) Demonstration authorized within the Technology and Innovation Deployment Program (TIDP) under the...

Research and Development of Wires and Cables for High-Field Accelerator Magnets

DOE PAGES

Barzi, Emanuela; Zlobin, Alexander V.

2016-02-18

The latest strategic plans for High Energy Physics endorse steadfast superconducting magnet technology R&D for future Energy Frontier Facilities. This includes 10 to 16 T Nb3Sn accelerator magnets for the luminosity upgrades of the Large Hadron Collider and eventually for a future 100 TeV scale proton-protonmore » $(pp)$ collider. This paper describes the multi-decade R&D investment in the $$Nb_3Sn$$ superconductor technology, which was crucial to produce the first reproducible 10 to 12 T accelerator-quality dipoles and quadrupoles, as well as their scale-up. We also indicate prospective research areas in superconducting $$Nb_3Sn$$ wires and cables to achieve the next goals for superconducting accelerator magnets. Emphasis is on increasing performance and decreasing costs while pushing the $$Nb_3Sn$$ technology to its limits for future $pp$ colliders.« less

Integrating shotcrete walls into the natural landscape by application of 'Green Walls'

NASA Astrophysics Data System (ADS)

Medl, Alexandra; Kikuta, Silvia

2017-04-01

Steep slopes resulting from major road infrastructure constructions are increasingly perceived as disagreeable disturbance in the landscape. Thus, a tool to consider landscape aspects and integrate these slopes into the natural environment is required. The challenge is to establish a sustainable vegetation layer despite of adverse circumstances such as inclinations of almost 90⁰, exposed position of slopes near streets and lack of soil and water supply. The objective of this study was to assess the performance of an innovative greening technology for vertical structures (shotcrete wall) in terms of vegetation development on varying plant substrates and geotextiles. The field experiment in Steinach am Brenner, Tyrol, Austria, included testing three plant substrates on basis of nearby rocky excavation material ('Innsbrucker Quarzphyllit', 'Bündnerschiefer' and 'Zentralgneis') combined with compost. Additionally, five geotextiles (geogrid (3x4 mm), geogrid (9x10 mm), coir net, coir mat, geo mat) were applied for evaluation. All test combinations were evaluated regarding vegetation cover and biomass production from 2015 to 2016. Analyses of chemical properties were conducted for all plant substrates. Results showed highest vegetation cover ratio on 'Bündnerschiefer' and 'Innsbrucker Quarzphyllit', which can be explained by the favorable mineral composition (nutrient storage capacity) and chemical properties of compost (lower values of electrical conductivity and C/N ratio). In conclusion, the use of 'Green Walls' filled with 'Bündnerschiefer' or 'Innsbrucker Quarzphyllit' plant substrate in combination with netlike geotextiles proved best, since geo grid and coir net turned out as most successful one year after installation. 'Green Walls' are promising in terms of establishing an optimal vegetation cover on vertical structures and are well suited for integrating shotcrete walls into the landscape. The use of local excavation material for greening purposes can be

Characterizing visible and invisible cell wall mutant phenotypes.

PubMed

Carpita, Nicholas C; McCann, Maureen C

2015-07-01

About 10% of a plant's genome is devoted to generating the protein machinery to synthesize, remodel, and deconstruct the cell wall. High-throughput genome sequencing technologies have enabled a reasonably complete inventory of wall-related genes that can be assembled into families of common evolutionary origin. Assigning function to each gene family member has been aided immensely by identification of mutants with visible phenotypes or by chemical and spectroscopic analysis of mutants with 'invisible' phenotypes of modified cell wall composition and architecture that do not otherwise affect plant growth or development. This review connects the inference of gene function on the basis of deviation from the wild type in genetic functional analyses to insights provided by modern analytical techniques that have brought us ever closer to elucidating the sequence structures of the major polysaccharide components of the plant cell wall. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Plant cell wall engineering: applications in biofuel production and improved human health.

PubMed

Burton, Rachel A; Fincher, Geoffrey B

2014-04-01

Plant cell walls consist largely of cellulose, non-cellulosic polysaccharides and lignin. Concerted attempts are underway to convert wall polysaccharides from crop plant residues into renewable transport fuels and other valuable products, and to exploit the dietary benefits of cereal grain wall polysaccharides in human health. Attempts to improve plant performance for these applications have involved the manipulation of the levels and structures of wall components. Some successes in altering non-cellulosic polysaccharides has been achieved, but it would appear that drastic changes in cellulose are more difficult to engineer. Nevertheless, future prospects for both genetically modified (GM) and non-GM technologies to modify plant cell wall composition and structure remain bright, and will undoubtedly find applications beyond the current focus on human health and biofuel production. Copyright © 2013. Published by Elsevier Ltd.

Report on a NASA astrobiology institute-funded workshop without walls: stellar stoichiometry.

PubMed

Desch, Steven J; Young, Patrick A; Anbar, Ariel D; Hinkel, Natalie; Pagano, Michael; Truitt, Amanda; Turnbull, Margaret

2014-04-01

We report on the NASA Astrobiology Institute-funded Workshop Without Walls entitled "Stellar Stoichiometry," hosted by the "Follow the Elements" team at Arizona State University in April 2013. We describe several innovative practices we adopted that made effective use of the Workshop Without Walls videoconferencing format, including use of information technologies, assignment of scientific tasks before the workshop, and placement of graduate students in positions of authority. A companion article will describe the scientific results arising from the workshop. Our intention here is to suggest best practices for future Workshops Without Walls.

Integrating the Wall Street Journal into AIS Courses

ERIC Educational Resources Information Center

Kohlmeyer, James M., III

2008-01-01

While it is important for accounting information systems (AIS) students to understand computer technology, internal controls and business processes, such knowledge is of little use without reference to appropriate contexts. Integrating Wall Street Journal (WSJ) readings and discussions into AIS classes can enrich learning by stimulating…

Investigation of advanced propulsion technologies: The RAM accelerator and the flowing gas radiation heater

NASA Technical Reports Server (NTRS)

Bruckner, A. P.; Knowlen, C.; Mattick, A. T.; Hertzberg, A.

1992-01-01

The two principal areas of advanced propulsion investigated are the ram accelerator and the flowing gas radiation heater. The concept of the ram accelerator is presented as a hypervelocity launcher for large-scale aeroballistic range applications in hypersonics and aerothermodynamics research. The ram accelerator is an in-bore ramjet device in which a projectile shaped like the centerbody of a supersonic ramjet is propelled in a stationary tube filled with a tailored combustible gas mixture. Combustion on and behind the projectile generates thrust which accelerates it to very high velocities. The acceleration can be tailored for the 'soft launch' of instrumented models. The distinctive reacting flow phenomena that have been observed in the ram accelerator are relevant to the aerothermodynamic processes in airbreathing hypersonic propulsion systems and are useful for validating sophisticated CFD codes. The recently demonstrated scalability of the device and the ability to control the rate of acceleration offer unique opportunities for the use of the ram accelerator as a large-scale hypersonic ground test facility. The flowing gas radiation receiver is a novel concept for using solar energy to heat a working fluid for space power or propulsion. Focused solar radiation is absorbed directly in a working gas, rather than by heat transfer through a solid surface. Previous theoretical analysis had demonstrated that radiation trapping reduces energy loss compared to that of blackbody receivers, and enables higher efficiencies and higher peak temperatures. An experiment was carried out to measure the temperature profile of an infrared-active gas and demonstrate the effect of radiation trapping. The success of this effort validates analytical models of heat transfer in this receiver, and confirms the potential of this approach for achieving high efficiency space power and propulsion.

Vacuum Brazing of Accelerator Components

NASA Astrophysics Data System (ADS)

Singh, Rajvir; Pant, K. K.; Lal, Shankar; Yadav, D. P.; Garg, S. R.; Raghuvanshi, V. K.; Mundra, G.

2012-11-01

Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

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.

Vibration isolation technology: Sensitivity of selected classes of experiments to residual accelerations

NASA Technical Reports Server (NTRS)

Alexander, J. Iwan D.

1990-01-01

The solution was sought of a 2-D axisymmetric moving boundary problem for the sensitivity of isothermal and nonisothermal liquid columns and the sensitivity of thermo-capillary flows to buoyancy driven convection caused by residual accelerations. The sensitivity of a variety of space experiments to residual accelerations are examined. In all the cases discussed, the sensitivity is related to the dynamic response of a fluid. In some cases the sensitivity can be defined by the magnitude of the response of the velocity field. This response may involve motion of the fluid associated with internal density gradients, or the motion of a free liquid surface. For fluids with internal density gradients, the type of acceleration to which the experiment is sensitive will depend on whether buoyancy driven convection must be small in comparison to other types of fluid motion (such as thermocapillary flow), or fluid motion must be suppressed or eliminated (such as in diffusion studies, or directional solidification experiments). The effect of the velocity on the composition and temperature field must be considered, particularly in the vicinity of the melt crystal interface. As far as the response to transient disturbances is concerned the sensitivity is determined by both the magnitude and frequency the acceleration and the characteristic momentum and solute diffusion times.

Simulating synchrotron radiation in accelerators including diffuse and specular reflections

DOE PAGES

Dugan, G.; Sagan, D.

2017-02-24

An accurate calculation of the synchrotron radiation flux within the vacuum chamber of an accelerator is needed for a number of applications. These include simulations of electron cloud effects and the design of radiation masking systems. To properly simulate the synchrotron radiation, it is important to include the scattering of the radiation at the vacuum chamber walls. To this end, a program called synrad3d has been developed which simulates the production and propagation of synchrotron radiation using a collection of photons. Photons generated by a charged particle beam are tracked from birth until they strike the vacuum chamber wall wheremore » the photon is either absorbed or scattered. Both specular and diffuse scattering is simulated. If a photon is scattered, it is further tracked through multiple encounters with the wall until it is finally absorbed. This paper describes the synrad3d program, with a focus on the details of its scattering model, and presents some examples of the program’s use.« less

Design and fabrication of one piece in-situ ribbed cell walls for application in an advanced AMTEC cell

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

Kramer, D.P.; McDougal, J.R.; Booher, R.A.

1998-07-01

Alkali Metal Thermal to Electrical Conversion (AMTEC) technology has been identified as a promising advanced space power technology with a predicted thermal to electrical conversion efficiency of {approximately}20%. The AMTEC technology has been the focus of several research endeavors in recent years and in essence it utilizes sodium and beta-alumina solid electrolyte tubes placed within a metal housing (cell wall) forming an AMTEC cell. The future application of the AMTEC technology, as the basis of an advanced power system for future deep space missions, is dependent on the development of AMTEC cells which will have the appropriate long term physicalmore » and mechanical properties to ensure the successful completion of the mission. The emphasis of this paper is on the design and fabrication of one piece in-situ ribbed cell walls for application in AMTEC cells. Novel machining and laser welding processes were employed which allowed the successful fabrication of the one piece thin walled 0.10mm--0.25mm (0.004--0.010in) cells. In-situ ribbed cell walls have the advantage over other cell wall designs in that the number of piece parts and the total weld area is reduced greatly simplifying fabrication. Test results show that the fabricated one piece cell walls were hermetic (helium leak rates of less than 1 {times} 10{sup {minus}8} cm{sup 3}/s) and had sufficient compression strength to meet mission requirements.« less

Reinforcement mechanism of multi-anchor wall with double wall facing

NASA Astrophysics Data System (ADS)

Suzuki, Kouta; Kobayashi, Makoto; Miura, Kinya; Konami, Takeharu; Hayashi, Taketo

2017-10-01

The reinforced soil wall has high seismic performance as generally known. However, the seismic behavior has not been clarified accurately yet, especially on multi-anchor wall with double wall facing. Indefinite behavior of reinforced soil wall during earthquake make us complicated in case with adopting to the abutment, because of arrangement of anchor plate as reinforcement often different according to the width of roads. In this study, a series of centrifuge model tests were carried out to investigate the reinforcement mechanism of multi anchor wall with double wall facing from the perspective of the vertical earth pressure. Several types of reinforce arrangement and rigid wall were applied in order to verify the arch function in the reinforced regions. The test results show unique behavior of vertical earth pressure, which was affected by arch action. All the vertical earth pressure placed behind facing panel, are larger than that of middle part between facing panel despite of friction between backfill and facing panel. Similar results were obtained in case using rigid wall. On the other hands, the vertical earth pressure, which were measured at the 3cm high from bottom of model container, shows larger than that of bottom. This results show the existence of arch action between double walls. In addition, it implies that the wall facing of such soil structure confined the backfill as pseudo wall, which is very reason that the multi anchor wall with double wall facing has high seismic performance.

Which Accelerates Faster--A Falling Ball or a Porsche?

ERIC Educational Resources Information Center

Rall, James D.; Abdul-Razzaq, Wathiq

2012-01-01

An introductory physics experiment has been developed to address the issues seen in conventional physics lab classes including assumption verification, technological dependencies, and real world motivation for the experiment. The experiment has little technology dependence and compares the acceleration due to gravity by using position versus time…

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.

Developing Use Cases for Evaluation of ADMS Applications to Accelerate Technology Adoption: Preprint

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

Veda, Santosh; Wu, Hongyu; Martin, Maurice

Grid modernization for the distribution systems comprise of the ability to effectively monitor and manage unplanned events while ensuring reliable operations. Integration of Distributed Energy Resources (DERs) and proliferation of autonomous smart controllers like microgrids and smart inverters in the distribution networks challenge the status quo of distribution system operations. Advanced Distribution Management System (ADMS) technologies are being increasingly deployed to manage the complexities of operating distribution systems. The ability to evaluate the ADMS applications in specific utility environments and for future scenarios will accelerate wider adoption of the ADMS and will lower the risks and costs of their implementation.more » This paper addresses the first step - identify and define the use cases for evaluating these applications. The applications that are selected for this discussion include Volt-VAr Optimization (VVO), Fault Location Isolation and Service Restoration (FLISR), Online Power Flow (OLPF)/Distribution System State Estimation (DSSE) and Market Participation. A technical description and general operational requirements for each of these applications is presented. The test scenarios that are most relevant to the utility challenges are also addressed.« less

Observation of 690 MV m -1 Electron Accelerating Gradient with a Laser-Driven Dielectric Microstructure

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

Wootton, K. P.; Wu, Z.; Cowan, B. M.

Acceleration of electrons using laser-driven dielectric microstructures is a promising technology for the miniaturization of particle accelerators. In this work, experimental results are presented of relativistic electron acceleration with 690±100 MVm -1 gradient. This is a record-high accelerating gradient for a dielectric microstructure accelerator, nearly doubling the previous record gradient. To reach higher acceleration gradients the present experiment employs 90 fs duration laser pulses.

Neural Networks for Modeling and Control of Particle Accelerators

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

Edelen, A. L.; Biedron, S. G.; Chase, B. E.

Myriad nonlinear and complex physical phenomena are host to particle accelerators. They often involve a multitude of interacting systems, are subject to tight performance demands, and should be able to run for extended periods of time with minimal interruptions. Often times, traditional control techniques cannot fully meet these requirements. One promising avenue is to introduce machine learning and sophisticated control techniques inspired by artificial intelligence, particularly in light of recent theoretical and practical advances in these fields. Within machine learning and artificial intelligence, neural networks are particularly well-suited to modeling, control, and diagnostic analysis of complex, nonlinear, and time-varying systems,more » as well as systems with large parameter spaces. Consequently, the use of neural network-based modeling and control techniques could be of significant benefit to particle accelerators. For the same reasons, particle accelerators are also ideal test-beds for these techniques. Moreover, many early attempts to apply neural networks to particle accelerators yielded mixed results due to the relative immaturity of the technology for such tasks. For the purpose of this paper is to re-introduce neural networks to the particle accelerator community and report on some work in neural network control that is being conducted as part of a dedicated collaboration between Fermilab and Colorado State University (CSU). We also describe some of the challenges of particle accelerator control, highlight recent advances in neural network techniques, discuss some promising avenues for incorporating neural networks into particle accelerator control systems, and describe a neural network-based control system that is being developed for resonance control of an RF electron gun at the Fermilab Accelerator Science and Technology (FAST) facility, including initial experimental results from a benchmark controller.« less

Neural Networks for Modeling and Control of Particle Accelerators

DOE PAGES

Edelen, A. L.; Biedron, S. G.; Chase, B. E.; ...

2016-04-01

Myriad nonlinear and complex physical phenomena are host to particle accelerators. They often involve a multitude of interacting systems, are subject to tight performance demands, and should be able to run for extended periods of time with minimal interruptions. Often times, traditional control techniques cannot fully meet these requirements. One promising avenue is to introduce machine learning and sophisticated control techniques inspired by artificial intelligence, particularly in light of recent theoretical and practical advances in these fields. Within machine learning and artificial intelligence, neural networks are particularly well-suited to modeling, control, and diagnostic analysis of complex, nonlinear, and time-varying systems,more » as well as systems with large parameter spaces. Consequently, the use of neural network-based modeling and control techniques could be of significant benefit to particle accelerators. For the same reasons, particle accelerators are also ideal test-beds for these techniques. Moreover, many early attempts to apply neural networks to particle accelerators yielded mixed results due to the relative immaturity of the technology for such tasks. For the purpose of this paper is to re-introduce neural networks to the particle accelerator community and report on some work in neural network control that is being conducted as part of a dedicated collaboration between Fermilab and Colorado State University (CSU). We also describe some of the challenges of particle accelerator control, highlight recent advances in neural network techniques, discuss some promising avenues for incorporating neural networks into particle accelerator control systems, and describe a neural network-based control system that is being developed for resonance control of an RF electron gun at the Fermilab Accelerator Science and Technology (FAST) facility, including initial experimental results from a benchmark controller.« less

Laser Acceleration of Ions for Radiation Therapy

NASA Astrophysics Data System (ADS)

Tajima, Toshiki; Habs, Dietrich; Yan, Xueqing

Ion beam therapy for cancer has proven to be a successful clinical approach, affording as good a cure as surgery and a higher quality of life. However, the ion beam therapy installation is large and expensive, limiting its availability for public benefit. One of the hurdles is to make the accelerator more compact on the basis of conventional technology. Laser acceleration of ions represents a rapidly developing young field. The prevailing acceleration mechanism (known as target normal sheath acceleration, TNSA), however, shows severe limitations in some key elements. We now witness that a new regime of coherent acceleration of ions by laser (CAIL) has been studied to overcome many of these problems and accelerate protons and carbon ions to high energies with higher efficiencies. Emerging scaling laws indicate possible realization of an ion therapy facility with compact, cost-efficient lasers. Furthermore, dense particle bunches may allow the use of much higher collective fields, reducing the size of beam transport and dump systems. Though ultimate realization of a laser-driven medical facility may take many years, the field is developing fast with many conceptual innovations and technical progress.

K-t GRAPPA-accelerated 4D flow MRI of liver hemodynamics: influence of different acceleration factors on qualitative and quantitative assessment of blood flow.

PubMed

Stankovic, Zoran; Fink, Jury; Collins, Jeremy D; Semaan, Edouard; Russe, Maximilian F; Carr, James C; Markl, Michael; Langer, Mathias; Jung, Bernd

2015-04-01

We sought to evaluate the feasibility of k-t parallel imaging for accelerated 4D flow MRI in the hepatic vascular system by investigating the impact of different acceleration factors. k-t GRAPPA accelerated 4D flow MRI of the liver vasculature was evaluated in 16 healthy volunteers at 3T with acceleration factors R = 3, R = 5, and R = 8 (2.0 × 2.5 × 2.4 mm(3), TR = 82 ms), and R = 5 (TR = 41 ms); GRAPPA R = 2 was used as the reference standard. Qualitative flow analysis included grading of 3D streamlines and time-resolved particle traces. Quantitative evaluation assessed velocities, net flow, and wall shear stress (WSS). Significant scan time savings were realized for all acceleration factors compared to standard GRAPPA R = 2 (21-71 %) (p < 0.001). Quantification of velocities and net flow offered similar results between k-t GRAPPA R = 3 and R = 5 compared to standard GRAPPA R = 2. Significantly increased leakage artifacts and noise were seen between standard GRAPPA R = 2 and k-t GRAPPA R = 8 (p < 0.001) with significant underestimation of peak velocities and WSS of up to 31 % in the hepatic arterial system (p <0.05). WSS was significantly underestimated up to 13 % in all vessels of the portal venous system for k-t GRAPPA R = 5, while significantly higher values were observed for the same acceleration with higher temporal resolution in two veins (p < 0.05). k-t acceleration of 4D flow MRI is feasible for liver hemodynamic assessment with acceleration factors R = 3 and R = 5 resulting in a scan time reduction of at least 40 % with similar quantitation of liver hemodynamics compared with GRAPPA R = 2.

Highly accelerated cardiovascular MR imaging using many channel technology: concepts and clinical applications

PubMed Central

Sodickson, Daniel K.

2010-01-01

Cardiovascular magnetic resonance imaging (CVMRI) is of proven clinical value in the non-invasive imaging of cardiovascular diseases. CVMRI requires rapid image acquisition, but acquisition speed is fundamentally limited in conventional MRI. Parallel imaging provides a means for increasing acquisition speed and efficiency. However, signal-to-noise (SNR) limitations and the limited number of receiver channels available on most MR systems have in the past imposed practical constraints, which dictated the use of moderate accelerations in CVMRI. High levels of acceleration, which were unattainable previously, have become possible with many-receiver MR systems and many-element, cardiac-optimized RF-coil arrays. The resulting imaging speed improvements can be exploited in a number of ways, ranging from enhancement of spatial and temporal resolution to efficient whole heart coverage to streamlining of CVMRI work flow. In this review, examples of these strategies are provided, following an outline of the fundamentals of the highly accelerated imaging approaches employed in CVMRI. Topics discussed include basic principles of parallel imaging; key requirements for MR systems and RF-coil design; practical considerations of SNR management, supported by multi-dimensional accelerations, 3D noise averaging and high field imaging; highly accelerated clinical state-of-the art cardiovascular imaging applications spanning the range from SNR-rich to SNR-limited; and current trends and future directions. PMID:17562047

Effect of acoustic coupling on power-law flame acceleration in spherical confinement

NASA Astrophysics Data System (ADS)

Akkerman, V'yacheslav; Law, Chung K.

2013-01-01

A model describing acoustically-generated parametric instability in a spherical chamber is developed for quasi-one-dimensional, low-Mach number flames. We demonstrate how sound waves generated by a centrally-ignited, outwardly-propagating accelerating flamefront can be incorporated into an existing theory of self-similar flame acceleration in free space [V. Akkerman, C. K. Law, and V. Bychkov, "Self-similar accelerative propagation of expanding wrinkled flames and explosion triggering," Phys. Rev. E 83, 026305 (2011)], 10.1103/PhysRevE.83.026305. Being reflected from the chamber wall, flame-generated acoustics interact with the flamefront and the attendant hydrodynamic flamefront cellular instability. This in turn affects the subsequent flame morphology and propagation speed. It is shown that the acoustics modify the power-law flame acceleration, concomitantly facilitating or inhibiting the transition to detonation in confinement, which allows reconciliation of a discrepancy in experimental measurements of different groups.

Study of strength kinetics of sand concrete system of accelerated hardening

NASA Astrophysics Data System (ADS)

Sharanova, A. V.; Lenkova, D. A.; Panfilova, A. D.

2018-04-01

Methods of calorimetric analysis are used to study the dynamics of the hydration processes of concretes with different accelerator contents. The efficiency of the isothermal calorimetry method is shown for study of strength kinetics of concrete mixtures of accelerated hardening, promising for additive technologies in civil engineering.

Through-Metal-Wall Power Delivery and Data Transmission for Enclosed Sensors: A Review

PubMed Central

Yang, Ding-Xin; Hu, Zheng; Zhao, Hong; Hu, Hai-Feng; Sun, Yun-Zhe; Hou, Bao-Jian

2015-01-01

The aim of this review was to assess the current viable technologies for wireless power delivery and data transmission through metal barriers. Using such technologies sensors enclosed in hermetical metal containers can be powered and communicate through exterior power sources without penetration of the metal wall for wire feed-throughs. In this review, we first discuss the significant and essential requirements for through-metal-wall power delivery and data transmission and then we: (1) describe three electromagnetic coupling based techniques reported in the literature, which include inductive coupling, capacitive coupling, and magnetic resonance coupling; (2) present a detailed review of wireless ultrasonic through-metal-wall power delivery and/or data transmission methods; (3) compare various ultrasonic through-metal-wall systems in modeling, transducer configuration and communication mode with sensors; (4) summarize the characteristics of electromagnetic-based and ultrasound-based systems, evaluate the challenges and development trends. We conclude that electromagnetic coupling methods are suitable for through thin non-ferromagnetic metal wall power delivery and data transmission at a relatively low data rate; piezoelectric transducer-based ultrasonic systems are particularly advantageous in achieving high power transfer efficiency and high data rates; the combination of more than one single technique may provide a more practical and reliable solution for long term operation. PMID:26694392

The structural response of a rail accelerator

NASA Technical Reports Server (NTRS)

Wang, S. Y.

1983-01-01

The transient response of a 0.4 by 0.6 cm rectangular bore rail accelerator was analyzed by a three dimensional finite element code. The copper rail deflected to a peak value of 0.08 mm in compression and then oscillated at an amplitude of 0.02 mm. Simultaneously the insulating side wall of glass fabric base, epoxy resin laminate (G-1o) was compressed to a peak value of 0.13 mm and rebounded to a steady state in extension. Projectile pinch or blowby due to the rail extension or compression, respectively, can be identified by examining the time history of the rail displacement. The effect of blowby was most significant at the side wall characterized by mm size displacement in compression. Dynamic stress calculations indicate that the G-10 supporting material behind the rail is subjected to over 21 MPa at which the G-10 could fail if the laminate was not carefully oriented. Results for a polycarbonate resin (Lexan) side wall show much larger displacements and stresses than for G-10. The tradeoff between the transparency of Lexan and the mechanical strength of G-10 for sidewall material is obvious. Displacement calculations from the modal method are smaller than the results from the direct integration method by almost an order of magnitude, because the high frequency effect is neglected.

Anomalous gravitropic response of Chara rhizoids during enhanced accelerations.

PubMed

Braun, M

1996-07-01

Centrifugal accelerations of 50-250 g were applied to rhizoids of Chara globularis Thuill. at stimulation angles (alpha) of 5-90 degrees between the acceleration vector and the rhizoid axis. After the start of centrifugation, the statoliths were pressed asymmetrically onto the centrifugal flank of the apical cell wall. In contrast to the well-known bending (by bowing) under 1 g, the rhizoids responded in two distinct phases. Following an initial phase of sharp bending (by bulging), which is similar to the negatively gravitropic response of Chara protonemata, rhizoids stopped bending and, in the second phase, grew straight in directions clearly deviating from the direction of acceleration. These response angles (beta) between the axis of the bent part of the rhizoid and the acceleration vector were strictly correlated with the g-level of acceleration. The higher the acceleration the greater was beta. Except for the sharp bending, the shape and growth rate of the centrifuged rhizoids were not different from those of gravistimulated control rhizoids at 1 g. These results indicate that gravitropic bending of rhizoids during enhanced accelerations (5 degrees < or = alpha < or = 90 degrees) is caused not only by subapical differential flank growth, as it is the case at 1 g, but also by also by the centripetal displacement of the growth centre as was recently discussed for the negative gravitropism of Chara protonemata. A hypothesis for cytoskeletally mediated polar growth is presented based on data from positive gravitropic bending of Chara rhizoids at 1 g and from the anomalous gravitropic bending of rhizoids compared with the negatively gravitropic bending of Chara protonemata. The data obtained are also relevant to a general understanding of graviperception in higher-plant organs.

Determination of the Airborne Sound Insulation of a Straw Bale Partition Wall

NASA Astrophysics Data System (ADS)

Teslík, Jiří; Fabian, Radek; Hrubá, Barbora

2017-06-01

This paper describes the results of a scientific project focused on determining of the Airborne Sound Insulation of a peripheral non-load bearing wall made of straw bales expressed by Weighted Sound Reduction Index. Weighted Sound Reduction Index was determined by measuring in the certified acoustic laboratory at the Faculty of Mechanical Engineering at Brno University of Technology. The measured structure of the straw wall was modified in combinations with various materials, so the results include a wide range of possible compositions of the wall. The key modification was application of plaster on both sides of the straw bale wall. This construction as is frequently done in actual straw houses. The additional measurements were performed on the straw wall with several variants of additional wall of slab materials. The airborne sound insulation value has been also measured in separate stages of the construction. Thus it is possible to compare and determinate the effect of the single layers on the airborne sound insulation.

PERMEABLE TREATMENT WALL EFFECTIVENESS MONITORING PROJECT, NEVADA STEWART MINE

EPA Science Inventory

This report summarizes the results of Mine Waste Technology Program (MWTP) Activity III, Project 39, Permeable Treatment Wall Effectiveness Monitoring Project, implemented and funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U.S. De...

A compact linear accelerator based on a scalable microelectromechanical-system RF-structure

NASA Astrophysics Data System (ADS)

Persaud, A.; Ji, Q.; Feinberg, E.; Seidl, P. A.; Waldron, W. L.; Schenkel, T.; Lal, A.; Vinayakumar, K. B.; Ardanuc, S.; Hammer, D. A.

2017-06-01

A new approach for a compact radio-frequency (RF) accelerator structure is presented. The new accelerator architecture is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC utilized RF resonators producing the accelerating fields and providing for higher beam currents through parallel beamlets focused using arrays of electrostatic quadrupoles (ESQs). While the early work obtained ESQs with lateral dimensions on the order of a few centimeters, using a printed circuit board (PCB), we reduce the characteristic dimension to the millimeter regime, while massively scaling up the potential number of parallel beamlets. Using Microelectromechanical systems scalable fabrication approaches, we are working on further reducing the characteristic dimension to the sub-millimeter regime. The technology is based on RF-acceleration components and ESQs implemented in the PCB or silicon wafers where each beamlet passes through beam apertures in the wafer. The complete accelerator is then assembled by stacking these wafers. This approach has the potential for fast and inexpensive batch fabrication of the components and flexibility in system design for application specific beam energies and currents. For prototyping the accelerator architecture, the components have been fabricated using the PCB. In this paper, we present proof of concept results of the principal components using the PCB: RF acceleration and ESQ focusing. Ongoing developments on implementing components in silicon and scaling of the accelerator technology to high currents and beam energies are discussed.

A compact linear accelerator based on a scalable microelectromechanical-system RF-structure.

PubMed

Persaud, A; Ji, Q; Feinberg, E; Seidl, P A; Waldron, W L; Schenkel, T; Lal, A; Vinayakumar, K B; Ardanuc, S; Hammer, D A

2017-06-01

A new approach for a compact radio-frequency (RF) accelerator structure is presented. The new accelerator architecture is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC utilized RF resonators producing the accelerating fields and providing for higher beam currents through parallel beamlets focused using arrays of electrostatic quadrupoles (ESQs). While the early work obtained ESQs with lateral dimensions on the order of a few centimeters, using a printed circuit board (PCB), we reduce the characteristic dimension to the millimeter regime, while massively scaling up the potential number of parallel beamlets. Using Microelectromechanical systems scalable fabrication approaches, we are working on further reducing the characteristic dimension to the sub-millimeter regime. The technology is based on RF-acceleration components and ESQs implemented in the PCB or silicon wafers where each beamlet passes through beam apertures in the wafer. The complete accelerator is then assembled by stacking these wafers. This approach has the potential for fast and inexpensive batch fabrication of the components and flexibility in system design for application specific beam energies and currents. For prototyping the accelerator architecture, the components have been fabricated using the PCB. In this paper, we present proof of concept results of the principal components using the PCB: RF acceleration and ESQ focusing. Ongoing developments on implementing components in silicon and scaling of the accelerator technology to high currents and beam energies are discussed.

Wind tunnels with adapted walls for reducing wall interference

NASA Technical Reports Server (NTRS)

Ganzer, U.

1979-01-01

The basic principle of adaptable wind tunnel walls is explained. First results of an investigation carried out at the Aero-Space Institute of Berlin Technical University are presented for two dimensional flexible walls and a NACA 0012 airfoil. With five examples exhibiting very different flow conditions it is demonstrated that it is possible to reduce wall interference and to avoid blockage at transonic speeds by wall adaptation.

Shake-table testing of a self-centering precast reinforced concrete frame with shear walls

NASA Astrophysics Data System (ADS)

Lu, Xilin; Yang, Boya; Zhao, Bin

2018-04-01

The seismic performance of a self-centering precast reinforced concrete (RC) frame with shear walls was investigated in this paper. The lateral force resistance was provided by self-centering precast RC shear walls (SPCW), which utilize a combination of unbonded prestressed post-tensioned (PT) tendons and mild steel reinforcing bars for flexural resistance across base joints. The structures concentrated deformations at the bottom joints and the unbonded PT tendons provided the self-centering restoring force. A 1/3-scale model of a five-story self-centering RC frame with shear walls was designed and tested on a shake-table under a series of bi-directional earthquake excitations with increasing intensity. The acceleration response, roof displacement, inter-story drifts, residual drifts, shear force ratios, hysteresis curves, and local behaviour of the test specimen were analysed and evaluated. The results demonstrated that seismic performance of the test specimen was satisfactory in the plane of the shear wall; however, the structure sustained inter-story drift levels up to 2.45%. Negligible residual drifts were recorded after all applied earthquake excitations. Based on the shake-table test results, it is feasible to apply and popularize a self-centering precast RC frame with shear walls as a structural system in seismic regions.

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.

Displacement of plasma protein and conduction velocity in rats under action of acceleration forces and hypokinesia

NASA Technical Reports Server (NTRS)

Baranski, S.; Edelwejn, Z.; Wojtkowiak, M.

1980-01-01

The permeability of capillary vessels was investigated in order to determine if acceleration alone or following prolonged hypokinesia would induce changes in the vascular wall leading to the penetration by l-albumins and/or proteins with larger molecules. In rats undergoing action of +5 Gz accelerations, no increase in vascular permeability, as tested with the use of (Cr-5k)-globulin, was demostrated. In rats immobilized for 4 weeks before centrifugation, rather weak migration of (Cr-51)-globulin from the vessels was observed. Immobilization resulted also in lowering of conduction velocity in the sciatic nerve.

Inverse measurement of wall pressure field in flexible-wall wind tunnels using global wall deformation data

NASA Astrophysics Data System (ADS)

Brown, Kenneth; Brown, Julian; Patil, Mayuresh; Devenport, William

2018-02-01

The Kevlar-wall anechoic wind tunnel offers great value to the aeroacoustics research community, affording the capability to make simultaneous aeroacoustic and aerodynamic measurements. While the aeroacoustic potential of the Kevlar-wall test section is already being leveraged, the aerodynamic capability of these test sections is still to be fully realized. The flexibility of the Kevlar walls suggests the possibility that the internal test section flow may be characterized by precisely measuring small deflections of the flexible walls. Treating the Kevlar fabric walls as tensioned membranes with known pre-tension and material properties, an inverse stress problem arises where the pressure distribution over the wall is sought as a function of the measured wall deflection. Experimental wall deformations produced by the wind loading of an airfoil model are measured using digital image correlation and subsequently projected onto polynomial basis functions which have been formulated to mitigate the impact of measurement noise based on a finite-element study. Inserting analytic derivatives of the basis functions into the equilibrium relations for a membrane, full-field pressure distributions across the Kevlar walls are computed. These inversely calculated pressures, after being validated against an independent measurement technique, can then be integrated along the length of the test section to give the sectional lift of the airfoil. Notably, these first-time results are achieved with a non-contact technique and in an anechoic environment.

Accelerating Innovation that Enhances Resource Recovery in the Wastewater Sector: Advancing a National Testbed Network.

PubMed

Mihelcic, James R; Ren, Zhiyong Jason; Cornejo, Pablo K; Fisher, Aaron; Simon, A J; Snyder, Seth W; Zhang, Qiong; Rosso, Diego; Huggins, Tyler M; Cooper, William; Moeller, Jeff; Rose, Bob; Schottel, Brandi L; Turgeon, Jason

2017-07-18

This Feature examines significant challenges and opportunities to spur innovation and accelerate adoption of reliable technologies that enhance integrated resource recovery in the wastewater sector through the creation of a national testbed network. The network is a virtual entity that connects appropriate physical testing facilities, and other components needed for a testbed network, with researchers, investors, technology providers, utilities, regulators, and other stakeholders to accelerate the adoption of innovative technologies and processes that are needed for the water resource recovery facility of the future. Here we summarize and extract key issues and developments, to provide a strategy for the wastewater sector to accelerate a path forward that leads to new sustainable water infrastructures.

Influence of environment factors on humidity conditions of selected external wall solutions in a heated building

NASA Astrophysics Data System (ADS)

Kaczmarek, Anna

2017-10-01

Contemporary single-family houses in Poland are often built during 3 quarters of a year (spring to autumn) are usually settled in a winter season. It is a special case when exploitation humidity coincides with technological one, causing unfavourable humidity conditions during the first years of exploitation. In consequence, thermal parameters of partitions differ from those assumed in the project. In construction stage the humidity state of a wall stabilizes as a result of water: associated with storage, entered technologically during wall construction and plastering, coming from rainfall. Thermo-insulation materials are built-in at dry state. During erection and exploitation of a building their thermal conductivity is changing depending on humidity conditions. According to building rules, construction humidity should be removed from a partition before the building transfer to usage, because it lowers the thermal partition insulation ability and increases air humidity of building interior. Walls are plastered and insulated in condition of simultaneous presence of atmospheric and technological humidity which cause special humidity condition during first years of exploitation. As a consequence, heating costs are substantially higher. In this article the results of simulation are shown performed with WUFI ®PRO 5 software, which was intended to define the time necessary for reaching the stabilised humidity in selected solutions of two-layer walls applied in a heated building. In the research performed, the partition orientation along geographic directions, short and long wave radiation, and environment humidity (air humidity, driving rain) coincidence with technological humidity in assumed wall solutions were taken into account.

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: ECR TECHNOLOGIES, INC., EARTHLINKED GROUND-SOURCE HEAT PUMP WATER HEATING SYSTEM

EPA Science Inventory

EPA has created the Environmental Technology Verification program to provide high quality, peer reviewed data on technology performance. This data is expected to accelerate the acceptance and use of improved environmental protection technologies. The Greenhouse Gas Technology C...

The influence of geopolitical change on the well-being of a population: the Berlin Wall.

PubMed Central

Héon-Klin, V; Sieber, E; Huebner, J; Fullilove, M T

2001-01-01

OBJECTIVES: Social cohesion is recognized as a fundamental condition for healthy populations, but social cohesion itself arises from political unity. The history of the Berlin Wall provides a unique opportunity to examine the effects of partition on social cohesion and, by inference, on health. METHODS: This ethnographic study consisted of examination of the territory formerly occupied by the Wall, formal and informal interviews with Berlin residents, and collection of cultural documents related to the Wall. Transcripts, field notes, and documents were examined by means of a keyword-in-context analysis. RESULTS: The separation of Berlin into 2 parts was a traumatic experience for the city's residents. After partition, East and West Germany had divergent social, cultural, and political experiences and gradually grew apart. CONCLUSIONS: The demolition of the Wall--the symbol and the instrument of partition--makes possible but does not ensure the reintegration of 2 populations that were separated for 40 years. The evolution of a new common culture might be accelerated by active attempts at cultural and social exchange. PMID:11236400

Experimental Investigation of Compliant Wall Surface Deformation in Turbulent Boundary Layer

NASA Astrophysics Data System (ADS)

Wang, Jin; Agarwal, Karuna; Katz, Joseph

2017-11-01

On-going research integrates Tomographic PIV (TPIV) with Mach-Zehnder Interferometry (MZI) to measure the correlations between deformation of a compliant wall and a turbulent channel flow or a boundary layer. Aiming to extend the scope to two-way coupling, in the present experiment the wall properties have been designed, based on a theoretical analysis, to increase the amplitude of deformation to several μm, achieving the same order of magnitude as the boundary layer wall unit (5-10 μm). It requires higher speeds and a softer surface that has a Young's modulus of 0.1MPa (vs. 1Mpa before), as well as proper thickness (5 mm) that maximize the wall response to excitation at scales that fall within the temporal and spatial resolution of the instruments. The experiments are performed in a water tunnel extension to the JHU refractive index matched facility. The transparent compliant surface is made of PDMS molded on the tunnel window, and measurements are performed at friction velocity Reynolds numbers in the 1000-7000 range. MZI measures the 2D surface deformation as several magnifications. The time-resolved 3D pressure distribution is determined by calculating to spatial distribution of material acceleration from the TPIV data and integrating it using a GPU-based, parallel-line, omni-directional integration method. ONR.

Accelerator infrastructure in Europe: EuCARD 2011

NASA Astrophysics Data System (ADS)

Romaniuk, Ryszard S.

2011-10-01

The paper presents a digest of the research results in the domain of accelerator science and technology in Europe, shown during the annual meeting of the EuCARD - European Coordination of Accelerator Research and Development. The conference concerns building of the research infrastructure, including in this advanced photonic and electronic systems for servicing large high energy physics experiments. There are debated a few basic groups of such systems like: measurement - control networks of large geometrical extent, multichannel systems for large amounts of metrological data acquisition, precision photonic networks of reference time, frequency and phase distribution.

Helium refrigeration systems for super-conducting accelerators

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

Ganni, V.

Many of the present day accelerators are based on superconducting technology which requires 4.5-K or 2-K helium refrigeration systems. These systems utilize superconducting radio frequency (SRF) cavities and/or superconducting magnets which are packaged into vacuum vessels known as cryo-modules (CM’s). Many of the present day accelerators are optimized to operate primarily at around 2-K, requiring specialized helium refrigeration systems which are cost intensive to produce and to operate. Some of the cryogenic refrigeration system design considerations for these challenging applications are discussed.

Overview of Accelerators with Potential Use in Homeland Security

NASA Astrophysics Data System (ADS)

Garnett, Robert W.

Quite a broad range of accelerators have been applied to solving many of the challenging problems related to homeland security and defense. These accelerator systems range from relatively small, simple, and compact, to large and complex, based on the specific application requirements. They have been used or proposed as sources of primary and secondary probe beams for applications such as radiography and to induce specific reactions that are key signatures for detecting conventional explosives or fissile material. A brief overview and description of these accelerator systems, their specifications, and application will be presented. Some recent technology trends will also be discussed.

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.

Design of High Efficiency High Power Electron Accelerator Systems Based on Normal Conducting RF Technology for Energy and Environmental Applications

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

Dolgashev, Valery; Tantawi, Sami

The goal of this project was to perform engineering design studies of three extremely high efficiency electron accelerators with the following parameters [1]: 2 MeV output beam energy and 1 MW average beam power; 10 MeV output energy and 10 MW; 10 MeV output energy and 1 MW. These linacs are intended for energy and environmental applications [2]. We based our designs on normal conducting radio-frequency technology. We have successfully reached this goal where we show rf-to-beam efficiency of 96.7 %, 97.2 %, and 79.6 % for these linacs.

Electron-beam dynamics for an advanced flash-radiography accelerator

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

Ekdahl, Carl August Jr.

2015-06-22

Beam dynamics issues were assessed for a new linear induction electron accelerator. Special attention was paid to equilibrium beam transport, possible emittance growth, and beam stability. Especially problematic would be high-frequency beam instabilities that could blur individual radiographic source spots, low-frequency beam motion that could cause pulse-to-pulse spot displacement, and emittance growth that could enlarge the source spots. Beam physics issues were examined through theoretical analysis and computer simulations, including particle-in cell (PIC) codes. Beam instabilities investigated included beam breakup (BBU), image displacement, diocotron, parametric envelope, ion hose, and the resistive wall instability. Beam corkscrew motion and emittance growth frommore » beam mismatch were also studied. It was concluded that a beam with radiographic quality equivalent to the present accelerators at Los Alamos will result if the same engineering standards and construction details are upheld.« less

Effect of Steel Framing for Securing Drywall Panels on Thermal and Humidity Parameters of the Outer Walls

NASA Astrophysics Data System (ADS)

Major, Maciej; Kosiń, Mariusz

2017-12-01

The paper analyses the effect of steel framing used to secure drywall panels on thermal and humidity properties of outer walls. In the practice of building a light structure, the most popular components are steel and wood studs. They are used to obtain framing for building a wall (an outer wall in this study). Analysis presented in this study concerned the corner of the outer wall build using the technology of light steel framing. Computer simulation was used to perform thermal and humidity analysis for the joint of the outer wall.

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.

Environmental Technology Verification: Pesticide Spray Drift Reduction Technologies for Row and Field Crops

EPA Pesticide Factsheets

The Environmental Technology Verification Program, established by the EPA, is designed to accelerate the development and commercialization of new or improved technologies through third-party verification and reporting of performance.

Project acceleration : making the leap from pilot to commercialization.

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

Borneo, Daniel R.

2010-05-01

Since the energy storage technology market is in a relatively emergent phase, narrowing the gap between pilot project status and commercialization is fundamental to the accelerating of this innovative market space. This session will explore regional market design factors to facilitate the storage enterprise. You will also hear about: quantifying transmission and generation efficiency enhancements; resource planning for storage; and assessing market mechanisms to accelerate storage adoption regionally.

Spontaneous Behaviors and Wall-Curvature Lead to Apparent Wall Preference in Planarian.

PubMed

Akiyama, Yoshitaro; Agata, Kiyokazu; Inoue, Takeshi

2015-01-01

The planarian Dugesia japonica tends to stay near the walls of its breeding containers and experimental dishes in the laboratory, a phenomenon called "wall preference". This behavior is thought to be important for environmental adaptation, such as hiding by planarians in nature. However, the mechanisms regulating wall-preference behavior are not well understood, since this behavior occurs in the absence of any particular stimulation. Here we show the mechanisms of wall-preference behavior. Surprisingly, planarian wall-preference behavior was also shown even by the head alone and by headless planarians. These results indicate that planarian "wall-preference" behavior only appears to be a "preference" behavior, and is actually an outcome of spontaneous behaviors, rather than of brain function. We found that in the absence of environmental cues planarians moved basically straight ahead until they reached a wall, and that after reaching a wall, they changed their direction of movement to one tangential to the wall, suggesting that this spontaneous behavior may play a critical role in the wall preference. When we tested another spontaneous behavior, the wigwag movement of the planarian head, using computer simulation with various wigwag angles and wigwag intervals, large wigwag angle and short wigwag interval reduced wall-preference behavior. This indicated that wigwag movement may determine the probability of staying near the wall or leaving the wall. Furthermore, in accord with this simulation, when we tested planarian wall-preference behavior using several assay fields with different curvature of the wall, we found that concavity and sharp curvature of walls negatively impacted wall preference by affecting the permissible angle of the wigwag movement. Together, these results indicate that planarian wall preference may be involuntarily caused by the combination of two spontaneous planarian behaviors: moving straight ahead until reaching a wall and then moving along it

Magnetic domain wall creep and depinning: A scalar field model approach

NASA Astrophysics Data System (ADS)

Caballero, Nirvana B.; Ferrero, Ezequiel E.; Kolton, Alejandro B.; Curiale, Javier; Jeudy, Vincent; Bustingorry, Sebastian

2018-06-01

Magnetic domain wall motion is at the heart of new magnetoelectronic technologies and hence the need for a deeper understanding of domain wall dynamics in magnetic systems. In this context, numerical simulations using simple models can capture the main ingredients responsible for the complex observed domain wall behavior. We present a scalar field model for the magnetization dynamics of quasi-two-dimensional systems with a perpendicular easy axis of magnetization which allows a direct comparison with typical experimental protocols, used in polar magneto-optical Kerr effect microscopy experiments. We show that the thermally activated creep and depinning regimes of domain wall motion can be reached and the effect of different quenched disorder implementations can be assessed with the model. In particular, we show that the depinning field increases with the mean grain size of a Voronoi tessellation model for the disorder.

Some ideas and opportunities concerning three-dimensional wind-tunnel wall corrections

NASA Technical Reports Server (NTRS)

Rubbert, P. E.

1982-01-01

Opportunities for improving the accuracy and reliability of wall corrections in conventional ventilated test sections are presented. The approach encompasses state-of-the-art technology in transonic computational methods combined with the measurement of tunnel-wall pressures. The objective is to arrive at correction procedures of known, verifiable accuracy that are practical within a production testing environment. It is concluded that: accurate and reliable correction procedures can be developed for cruise-type aerodynamic testing for any wall configuration; passive walls can be optimized for minimal interference for cruise-type aerodynamic testing (tailored slots, variable open area ratio, etc.); monitoring and assessment of noncorrectable interference (buoyancy and curvature in a transonic stream) can be an integral part of a correction procedure; and reasonably good correction procedures can probably be developd for complex flows involving extensive separation and other unpredictable phenomena.

Beryllium liner implosion experiments on the Z accelerator in preparation for magnetized liner inertial fusiona)

NASA Astrophysics Data System (ADS)

McBride, R. D.; Martin, M. R.; Lemke, R. W.; Greenly, J. B.; Jennings, C. A.; Rovang, D. C.; Sinars, D. B.; Cuneo, M. E.; Herrmann, M. C.; Slutz, S. A.; Nakhleh, C. W.; Ryutov, D. D.; Davis, J.-P.; Flicker, D. G.; Blue, B. E.; Tomlinson, K.; Schroen, D.; Stamm, R. M.; Smith, G. E.; Moore, J. K.; Rogers, T. J.; Robertson, G. K.; Kamm, R. J.; Smith, I. C.; Savage, M.; Stygar, W. A.; Rochau, G. A.; Jones, M.; Lopez, M. R.; Porter, J. L.; Matzen, M. K.

2013-05-01

Multiple experimental campaigns have been executed to study the implosions of initially solid beryllium (Be) liners (tubes) on the Z pulsed-power accelerator. The implosions were driven by current pulses that rose from 0 to 20 MA in either 100 or 200 ns (200 ns for pulse shaping experiments). These studies were conducted in support of the recently proposed Magnetized Liner Inertial Fusion concept [Slutz et al., Phys. Plasmas 17, 056303 (2010)], as well as for exploring novel equation-of-state measurement techniques. The experiments used thick-walled liners that had an aspect ratio (initial outer radius divided by initial wall thickness) of either 3.2, 4, or 6. From these studies, we present three new primary results. First, we present radiographic images of imploding Be liners, where each liner contained a thin aluminum sleeve for enhancing the contrast and visibility of the liner's inner surface in the images. These images allow us to assess the stability of the liner's inner surface more accurately and more directly than was previously possible. Second, we present radiographic images taken early in the implosion (prior to any motion of the liner's inner surface) of a shockwave propagating radially inward through the liner wall. Radial mass density profiles from these shock compression experiments are contrasted with profiles from experiments where the Z accelerator's pulse shaping capabilities were used to achieve shockless ("quasi-isentropic") liner compression. Third, we present "micro-Ḃ" measurements of azimuthal magnetic field penetration into the initially vacuum-filled interior of a shocked liner. Our measurements and simulations reveal that the penetration commences shortly after the shockwave breaks out from the liner's inner surface. The field then accelerates this low-density "precursor" plasma to the axis of symmetry.

Beryllium liner implosion experiments on the Z accelerator in preparation for magnetized liner inertial fusion

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

McBride, R. D.; Martin, M. R.; Lemke, R. W.

Multiple experimental campaigns have been executed to study the implosions of initially solid beryllium (Be) liners (tubes) on the Z pulsed-power accelerator. The implosions were driven by current pulses that rose from 0 to 20 MA in either 100 or 200 ns (200 ns for pulse shaping experiments). These studies were conducted in support of the recently proposed Magnetized Liner Inertial Fusion concept [Slutz et al., Phys. Plasmas 17, 056303 (2010)], as well as for exploring novel equation-of-state measurement techniques. The experiments used thick-walled liners that had an aspect ratio (initial outer radius divided by initial wall thickness) of eithermore » 3.2, 4, or 6. From these studies, we present three new primary results. First, we present radiographic images of imploding Be liners, where each liner contained a thin aluminum sleeve for enhancing the contrast and visibility of the liner's inner surface in the images. These images allow us to assess the stability of the liner's inner surface more accurately and more directly than was previously possible. Second, we present radiographic images taken early in the implosion (prior to any motion of the liner's inner surface) of a shockwave propagating radially inward through the liner wall. Radial mass density profiles from these shock compression experiments are contrasted with profiles from experiments where the Z accelerator's pulse shaping capabilities were used to achieve shockless (“quasi-isentropic”) liner compression. Third, we present “micro-B-dot ” measurements of azimuthal magnetic field penetration into the initially vacuum-filled interior of a shocked liner. Our measurements and simulations reveal that the penetration commences shortly after the shockwave breaks out from the liner's inner surface. The field then accelerates this low-density “precursor” plasma to the axis of symmetry.« less

Demonstration of acceleration of relativistic electrons at a dielectric microstructure using femtosecond laser pulses

DOE PAGES

Wootton, Kent P.; Wu, Ziran; Cowan, Benjamin M.; ...

2016-06-02

Acceleration of electrons using laser-driven dielectric microstructures is a promising technology for the miniaturization of particle accelerators. Achieving the desired GV m –1 accelerating gradients is possible only with laser pulse durations shorter than ~1 ps. In this Letter, we present, to the best of our knowledge, the first demonstration of acceleration of relativistic electrons at a dielectric microstructure driven by femtosecond duration laser pulses. Furthermore, using this technique, an electron accelerating gradient of 690±100 MV m –1 was measured—a record for dielectric laser accelerators.

Intraventricular flow alterations due to dyssynchronous wall motion

NASA Astrophysics Data System (ADS)

Pope, Audrey M.; Lai, Hong Kuan; Samaee, Milad; Santhanakrishnan, Arvind

2015-11-01

Roughly 30% of patients with systolic heart failure suffer from left ventricular dyssynchrony (LVD), in which mechanical discoordination of the ventricle walls leads to poor hemodynamics and suboptimal cardiac function. There is currently no clear mechanistic understanding of how abnormalities in septal-lateral (SL) wall motion affects left ventricle (LV) function, which is needed to improve the treatment of LVD using cardiac resynchronization therapy. We use an experimental flow phantom with an LV physical model to study mechanistic effects of SL wall motion delay on LV function. To simulate mechanical LVD, two rigid shafts were coupled to two segments (apical and mid sections) along the septal wall of the LV model. Flow through the LV model was driven using a piston pump, and stepper motors coupled to the above shafts were used to locally perturb the septal wall segments relative to the pump motion. 2D PIV was used to examine the intraventricular flow through the LV physical model. Alterations to SL delay results in a reduction in the kinetic energy (KE) of the flow field compared to synchronous SL motion. The effect of varying SL motion delay from 0% (synchronous) to 100% (out-of-phase) on KE and viscous dissipation will be presented. This research was supported by the Oklahoma Center for Advancement of Science and Technology (HR14-022).

Cloud Computing and Validated Learning for Accelerating Innovation in IoT

ERIC Educational Resources Information Center

Suciu, George; Todoran, Gyorgy; Vulpe, Alexandru; Suciu, Victor; Bulca, Cristina; Cheveresan, Romulus

2015-01-01

Innovation in Internet of Things (IoT) requires more than just creation of technology and use of cloud computing or big data platforms. It requires accelerated commercialization or aptly called go-to-market processes. To successfully accelerate, companies need a new type of product development, the so-called validated learning process.…

Study on construction technology of metro tunnel under a glass curtain wall

NASA Astrophysics Data System (ADS)

Zhang, Jian; Yu, Deqiang

2018-03-01

To ensure the safety of the glass curtain wall building above loess tunnel and get an optimal scheme, an elastic-plastic FEM model is established to simulate three reinforcement schemes based on a tunnel section in Xi’an Metro Line 3. The results show that the settlement value of the optimal scheme is reduced by 69.89% compared with the drainage measures, and the uneven settlement value is reduced by 57.5%. The construction points, technical processes and technical indexes of the optimal scheme are introduced. According to the actual project, the cumulative settlement of the building under construction is 16mm, which meets the control standards. According to the actual project, the cumulative settlement of the glass curtain wall building is 16mm, which meets the control standards. The reinforcement scheme can provide some reference for the design and construction of the metro in loess area.

Disentangling the role of athermal walls on the Knudsen paradox in molecular and granular gases

NASA Astrophysics Data System (ADS)

Gupta, Ronak; Alam, Meheboob

2018-01-01

The nature of particle-wall interactions is shown to have a profound impact on the well-known "Knudsen paradox" [or the "Knudsen minimum" effect, which refers to the decrease of the mass-flow rate of a gas with increasing Knudsen number Kn, reaching a minimum at Kn˜O (1 ) and increasing logarithmically with Kn as Kn→∞ ] in the acceleration-driven Poiseuille flow of rarefied gases. The nonmonotonic variation of the flow rate with Kn occurs even in a granular or dissipative gas in contact with thermal walls. The latter result is in contradiction with recent work [Alam et al., J. Fluid Mech. 782, 99 (2015), 10.1017/jfm.2015.523] that revealed the absence of the Knudsen minimum in granular Poiseuille flow for which the flow rate was found to decrease at large values of Kn. The above conundrum is resolved by distinguishing between "thermal" and "athermal" walls, and it is shown that, for both molecular and granular gases, the momentum transfer to athermal walls is much different than that to thermal walls which is directly responsible for the anomalous flow-rate variation with Kn in the rarefied regime. In the continuum limit of Kn→0 , the athermal walls are shown to be closely related to "no-flux" ("adiabatic") walls for which the Knudsen minimum does not exist either. A possible characterization of athermal walls in terms of (1) an effective specularity coefficient for the slip velocity and (2) a flux-type boundary condition for granular temperature is suggested based on simulation results.

Pulsatile flows and wall-shear stresses in models simulating normal and stenosed aortic arches

NASA Astrophysics Data System (ADS)

Huang, Rong Fung; Yang, Ten-Fang; Lan, Y.-K.

2010-03-01

Pulsatile aqueous glycerol solution flows in the models simulating normal and stenosed human aortic arches are measured by means of particle image velocimetry. Three transparent models were used: normal, 25% stenosed, and 50% stenosed aortic arches. The Womersley parameter, Dean number, and time-averaged Reynolds number are 17.31, 725, and 1,081, respectively. The Reynolds numbers based on the peak velocities of the normal, 25% stenosed, and 50% stenosed aortic arches are 2,484, 3,456, and 3,931, respectively. The study presents the temporal/spatial evolution processes of the flow pattern, velocity distribution, and wall-shear stress during the systolic and diastolic phases. It is found that the flow pattern evolving in the central plane of normal and stenosed aortic arches exhibits (1) a separation bubble around the inner arch, (2) a recirculation vortex around the outer arch wall upstream of the junction of the brachiocephalic artery, (3) an accelerated main stream around the outer arch wall near the junctions of the left carotid and the left subclavian arteries, and (4) the vortices around the entrances of the three main branches. The study identifies and discusses the reasons for the flow physics’ contribution to the formation of these features. The oscillating wall-shear stress distributions are closely related to the featured flow structures. On the outer wall of normal and slightly stenosed aortas, large wall-shear stresses appear in the regions upstream of the junction of the brachiocephalic artery as well as the corner near the junctions of the left carotid artery and the left subclavian artery. On the inner wall, the largest wall-shear stress appears in the region where the boundary layer separates.

Spatial gradients in cell wall composition and transcriptional profiles along elongating maize internodes

PubMed Central

2014-01-01

Background The elongating maize internode represents a useful system for following development of cell walls in vegetative cells in the Poaceae family. Elongating internodes can be divided into four developmental zones, namely the basal intercalary meristem, above which are found the elongation, transition and maturation zones. Cells in the basal meristem and elongation zones contain mainly primary walls, while secondary cell wall deposition accelerates in the transition zone and predominates in the maturation zone. Results The major wall components cellulose, lignin and glucuronoarabinoxylan (GAX) increased without any abrupt changes across the elongation, transition and maturation zones, although GAX appeared to increase more between the elongation and transition zones. Microarray analyses show that transcript abundance of key glycosyl transferase genes known to be involved in wall synthesis or re-modelling did not match the increases in cellulose, GAX and lignin. Rather, transcript levels of many of these genes were low in the meristematic and elongation zones, quickly increased to maximal levels in the transition zone and lower sections of the maturation zone, and generally decreased in the upper maturation zone sections. Genes with transcript profiles showing this pattern included secondary cell wall CesA genes, GT43 genes, some β-expansins, UDP-Xylose synthase and UDP-Glucose pyrophosphorylase, some xyloglucan endotransglycosylases/hydrolases, genes involved in monolignol biosynthesis, and NAM and MYB transcription factor genes. Conclusions The data indicated that the enzymic products of genes involved in cell wall synthesis and modification remain active right along the maturation zone of elongating maize internodes, despite the fact that corresponding transcript levels peak earlier, near or in the transition zone. PMID:24423166

Wall Modeled Large Eddy Simulation of Airfoil Trailing Edge Noise

NASA Astrophysics Data System (ADS)

Kocheemoolayil, Joseph; Lele, Sanjiva

2014-11-01

Large eddy simulation (LES) of airfoil trailing edge noise has largely been restricted to low Reynolds numbers due to prohibitive computational cost. Wall modeled LES (WMLES) is a computationally cheaper alternative that makes full-scale Reynolds numbers relevant to large wind turbines accessible. A systematic investigation of trailing edge noise prediction using WMLES is conducted. Detailed comparisons are made with experimental data. The stress boundary condition from a wall model does not constrain the fluctuating velocity to vanish at the wall. This limitation has profound implications for trailing edge noise prediction. The simulation over-predicts the intensity of fluctuating wall pressure and far-field noise. An improved wall model formulation that minimizes the over-prediction of fluctuating wall pressure is proposed and carefully validated. The flow configurations chosen for the study are from the workshop on benchmark problems for airframe noise computations. The large eddy simulation database is used to examine the adequacy of scaling laws that quantify the dependence of trailing edge noise on Mach number, Reynolds number and angle of attack. Simplifying assumptions invoked in engineering approaches towards predicting trailing edge noise are critically evaluated. We gratefully acknowledge financial support from GE Global Research and thank Cascade Technologies Inc. for providing access to their massively-parallel large eddy simulation framework.

A compact linear accelerator based on a scalable microelectromechanical-system RF-structure

DOE PAGES

Persaud, A.; Ji, Q.; Feinberg, E.; ...

2017-06-08

Here, a new approach for a compact radio-frequency (RF) accelerator structure is presented. The new accelerator architecture is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC utilized RF resonators producing the accelerating fields and providing for higher beam currents through parallel beamlets focused using arrays of electrostatic quadrupoles (ESQs). While the early work obtained ESQs with lateral dimensions on the order of a few centimeters, using a printed circuit board (PCB), we reduce the characteristic dimension to the millimeter regime, while massively scaling up the potential number ofmore » parallel beamlets. Using Microelectromechanical systems scalable fabrication approaches, we are working on further red ucing the characteristic dimension to the sub-millimeter regime. The technology is based on RF-acceleration components and ESQs implemented in the PCB or silicon wafers where each beamlet passes through beam apertures in the wafer. The complete accelerator is then assembled by stacking these wafers. This approach has the potential for fast and inexpensive batch fabrication of the components and flexibility in system design for application specific beam energies and currents. For prototyping the accelerator architecture, the components have been fabricated using the PCB. In this paper, we present proof of concept results of the principal components using the PCB: RF acceleration and ESQ focusing. Finally, ongoing developments on implementing components in silicon and scaling of the accelerator technology to high currents and beam energies are discussed.« less

Wall shear stress measurement in blade end-wall corner region

NASA Technical Reports Server (NTRS)

Bhargava, R.; Raj, R.; Boldman, D. R.

1987-01-01

The magnitude and the direction of wall shear stress and surface pressure in the blade end-wall corner region were investigated. The measurements were obtained on a specially designed Preston tube, the tip of which could be concentrically rotated about its axis of rotation at the measurement location. The magnitude of wall shear stress in the vicinity of the corner was observed to increase significantly (170 percent) compared to its far-upstream value; the increase was consistently higher on the blade surface compared to the value on the plate surface of the blade end-wall corner. On both surfaces in the blade end-wall corner, the variation of the wall shear stress direction was found to be more predominant in the vicinity of the blade leading-edge location. The trend of the measured wall shear stress direction showed good agreement with the limiting streamline directions obtained from the flow visualization studies.

Wall-based identification of coherent structures in wall-bounded turbulence

NASA Astrophysics Data System (ADS)

Sanmiguel Vila, C.; Flores, O.

2018-04-01

During the last decades, a number of reduced order models based on coherent structures have been proposed to describe wall-bounded turbulence. Many of these models emphasize the importance of coherent wall-normal velocity eddies (ν-eddies), which drive the generation of the very long streamwise velocity structures observed in the logarithmic and outer region. In order to use these models to improve our ability to control wall-bounded turbulence in realistic applications, these ν-eddies need to be identified from the wall in a non-intrusive way. In this paper, the possibility of using the pressure signal at the wall to identify these ν-eddies is explored, analyzing the cross-correlation between the wall-normal velocity component and the pressure fluctuations at the wall in a DNS of a turbulent channel flow at Reτ = 939. The results show that the cross-correlation has a region of negative correlation upstream, and a region of positive correlation backwards. In the spanwise direction the correlation decays monotonously, except very close to the wall where a change of sign of the correlation coefficient is observed. Moreover, filtering the pressure fluctuations at the wall in space results in an increase of the region where the cross-correlation is strong, both for the positively and the negatively correlated regions. The use of a time filter for the pressure fluctuations at the wall yields different results, displacing the regions of strong correlation without changing much their sizes. The results suggest that space-filtering the pressure at the wall is a feasible way to identify ν-eddies of different sizes, which could be used to trigger turbulent control strategies.

Spontaneous Behaviors and Wall-Curvature Lead to Apparent Wall Preference in Planarian

PubMed Central

Akiyama, Yoshitaro; Agata, Kiyokazu; Inoue, Takeshi

2015-01-01

The planarian Dugesia japonica tends to stay near the walls of its breeding containers and experimental dishes in the laboratory, a phenomenon called “wall preference”. This behavior is thought to be important for environmental adaptation, such as hiding by planarians in nature. However, the mechanisms regulating wall-preference behavior are not well understood, since this behavior occurs in the absence of any particular stimulation. Here we show the mechanisms of wall-preference behavior. Surprisingly, planarian wall-preference behavior was also shown even by the head alone and by headless planarians. These results indicate that planarian “wall-preference” behavior only appears to be a “preference” behavior, and is actually an outcome of spontaneous behaviors, rather than of brain function. We found that in the absence of environmental cues planarians moved basically straight ahead until they reached a wall, and that after reaching a wall, they changed their direction of movement to one tangential to the wall, suggesting that this spontaneous behavior may play a critical role in the wall preference. When we tested another spontaneous behavior, the wigwag movement of the planarian head, using computer simulation with various wigwag angles and wigwag intervals, large wigwag angle and short wigwag interval reduced wall-preference behavior. This indicated that wigwag movement may determine the probability of staying near the wall or leaving the wall. Furthermore, in accord with this simulation, when we tested planarian wall-preference behavior using several assay fields with different curvature of the wall, we found that concavity and sharp curvature of walls negatively impacted wall preference by affecting the permissible angle of the wigwag movement. Together, these results indicate that planarian wall preference may be involuntarily caused by the combination of two spontaneous planarian behaviors: moving straight ahead until reaching a wall and then

Domain wall nanoelectronics

NASA Astrophysics Data System (ADS)

Catalan, G.; Seidel, J.; Ramesh, R.; Scott, J. F.

2012-01-01

Domains in ferroelectrics were considered to be well understood by the middle of the last century: They were generally rectilinear, and their walls were Ising-like. Their simplicity stood in stark contrast to the more complex Bloch walls or Néel walls in magnets. Only within the past decade and with the introduction of atomic-resolution studies via transmission electron microscopy, electron holography, and atomic force microscopy with polarization sensitivity has their real complexity been revealed. Additional phenomena appear in recent studies, especially of magnetoelectric materials, where functional properties inside domain walls are being directly measured. In this paper these studies are reviewed, focusing attention on ferroelectrics and multiferroics but making comparisons where possible with magnetic domains and domain walls. An important part of this review will concern device applications, with the spotlight on a new paradigm of ferroic devices where the domain walls, rather than the domains, are the active element. Here magnetic wall microelectronics is already in full swing, owing largely to the work of Cowburn and of Parkin and their colleagues. These devices exploit the high domain wall mobilities in magnets and their resulting high velocities, which can be supersonic, as shown by Kreines’ and co-workers 30 years ago. By comparison, nanoelectronic devices employing ferroelectric domain walls often have slower domain wall speeds, but may exploit their smaller size as well as their different functional properties. These include domain wall conductivity (metallic or even superconducting in bulk insulating or semiconducting oxides) and the fact that domain walls can be ferromagnetic while the surrounding domains are not.

A Comparison of graphene hydrogels modified with single-walled/multi-walled carbon nanotubes as electrode materials for capacitive deionization.

PubMed

Cao, Jianglin; Wang, Ying; Chen, Chunyang; Yu, Fei; Ma, Jie

2018-05-15

Capacitive deionization (CDI) is a technology used to remove salt from brackish water, and it is an energy-saving, low-cost method compared with other methods, such as reverse osmosis, multi-stage ash distillation and electrodialysis. In this paper, three-dimensional (3D) graphene hydrogels modified with single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) were synthesized by a one-step water bath method to increase the conductivity of materials and reduce the aggregation of the graphene sheets. The CDI performance differences between the two materials were compared and discussed. The results suggested that SWCNTs/rGO had a higher electrosorption capacity (48.73 mg/g) than MWCNTs/rGO, and this was attributed to its high specific surface area (308.37 m 2 /g), specific capacity (36.35 F/g), and smaller charge transfer resistance compared with those of the MWCNTs/rGO electrode. The results indicate SWCNTs/rGO is a promising and suitable material for CDI technology and we provide basic guidance for further CNTs/graphene composite research. Copyright © 2018 Elsevier Inc. All rights reserved.

19. INTERIOR OF UTILITY ROOM SHOWING STUCCO WALL/DRYWALL WALL TRANSITION, ...

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

19. INTERIOR OF UTILITY ROOM SHOWING STUCCO WALL/DRYWALL WALL TRANSITION, ELECTRICAL JUNCTION BOXES, BUILT-IN WALL CABINETRY, AND ELECTRICAL WALL HEATER. VIEW TO NORTHEAST. - Bishop Creek Hydroelectric System, Plant 4, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA

On fully three-dimensional resistive wall mode and feedback stabilization computations

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

Strumberger, E.; Merkel, P.; Sempf, M.

2008-05-15

Resistive walls, located close to the plasma boundary, reduce the growth rates of external kink modes to resistive time scales. For such slowly growing resistive wall modes, the stabilization by an active feedback system becomes feasible. The fully three-dimensional stability code STARWALL, and the feedback optimization code OPTIM have been developed [P. Merkel and M. Sempf, 21st IAEA Fusion Energy Conference 2006, Chengdu, China (International Atomic Energy Agency, Vienna, 2006, paper TH/P3-8] to compute the growth rates of resistive wall modes in the presence of nonaxisymmetric, multiply connected wall structures and to model the active feedback stabilization of these modes.more » In order to demonstrate the capabilities of the codes and to study the effect of the toroidal mode coupling caused by multiply connected wall structures, the codes are applied to test equilibria using the resistive wall structures currently under debate for ITER [M. Shimada et al., Nucl. Fusion 47, S1 (2007)] and ASDEX Upgrade [W. Koeppendoerfer et al., Proceedings of the 16th Symposium on Fusion Technology, London, 1990 (Elsevier, Amsterdam, 1991), Vol. 1, p. 208].« less

On fully three-dimensional resistive wall mode and feedback stabilization computationsa)

NASA Astrophysics Data System (ADS)

Strumberger, E.; Merkel, P.; Sempf, M.; Günter, S.

2008-05-01

Resistive walls, located close to the plasma boundary, reduce the growth rates of external kink modes to resistive time scales. For such slowly growing resistive wall modes, the stabilization by an active feedback system becomes feasible. The fully three-dimensional stability code STARWALL, and the feedback optimization code OPTIM have been developed [P. Merkel and M. Sempf, 21st IAEA Fusion Energy Conference 2006, Chengdu, China (International Atomic Energy Agency, Vienna, 2006, paper TH/P3-8] to compute the growth rates of resistive wall modes in the presence of nonaxisymmetric, multiply connected wall structures and to model the active feedback stabilization of these modes. In order to demonstrate the capabilities of the codes and to study the effect of the toroidal mode coupling caused by multiply connected wall structures, the codes are applied to test equilibria using the resistive wall structures currently under debate for ITER [M. Shimada et al., Nucl. Fusion 47, S1 (2007)] and ASDEX Upgrade [W. Köppendörfer et al., Proceedings of the 16th Symposium on Fusion Technology, London, 1990 (Elsevier, Amsterdam, 1991), Vol. 1, p. 208].

Ensemble Manifold Rank Preserving for Acceleration-Based Human Activity Recognition.

PubMed

Tao, Dapeng; Jin, Lianwen; Yuan, Yuan; Xue, Yang

2016-06-01

With the rapid development of mobile devices and pervasive computing technologies, acceleration-based human activity recognition, a difficult yet essential problem in mobile apps, has received intensive attention recently. Different acceleration signals for representing different activities or even a same activity have different attributes, which causes troubles in normalizing the signals. We thus cannot directly compare these signals with each other, because they are embedded in a nonmetric space. Therefore, we present a nonmetric scheme that retains discriminative and robust frequency domain information by developing a novel ensemble manifold rank preserving (EMRP) algorithm. EMRP simultaneously considers three aspects: 1) it encodes the local geometry using the ranking order information of intraclass samples distributed on local patches; 2) it keeps the discriminative information by maximizing the margin between samples of different classes; and 3) it finds the optimal linear combination of the alignment matrices to approximate the intrinsic manifold lied in the data. Experiments are conducted on the South China University of Technology naturalistic 3-D acceleration-based activity dataset and the naturalistic mobile-devices based human activity dataset to demonstrate the robustness and effectiveness of the new nonmetric scheme for acceleration-based human activity recognition.

Logic and memory concepts for all-magnetic computing based on transverse domain walls

NASA Astrophysics Data System (ADS)

Vandermeulen, J.; Van de Wiele, B.; Dupré, L.; Van Waeyenberge, B.

2015-06-01

We introduce a non-volatile digital logic and memory concept in which the binary data is stored in the transverse magnetic domain walls present in in-plane magnetized nanowires with sufficiently small cross sectional dimensions. We assign the digital bit to the two possible orientations of the transverse domain wall. Numerical proofs-of-concept are presented for a NOT-, AND- and OR-gate, a FAN-out as well as a reading and writing device. Contrary to the chirality based vortex domain wall logic gates introduced in Omari and Hayward (2014 Phys. Rev. Appl. 2 044001), the presented concepts remain applicable when miniaturized and are driven by electrical currents, making the technology compatible with the in-plane racetrack memory concept. The individual devices can be easily combined to logic networks working with clock speeds that scale linearly with decreasing design dimensions. This opens opportunities to an all-magnetic computing technology where the digital data is stored and processed under the same magnetic representation.

On Markov modelling of near-wall turbulent shear flow

NASA Astrophysics Data System (ADS)

Reynolds, A. M.

1999-11-01

The role of Reynolds number in determining particle trajectories in near-wall turbulent shear flow is investigated in numerical simulations using a second-order Lagrangian stochastic (LS) model (Reynolds, A.M. 1999: A second-order Lagrangian stochastic model for particle trajectories in inhomogeneous turbulence. Quart. J. Roy. Meteorol. Soc. (In Press)). In such models, it is the acceleration, velocity and position of a particle rather than just its velocity and position which are assumed to evolve jointly as a continuous Markov process. It is found that Reynolds number effects are significant in determining simulated particle trajectories in the viscous sub-layer and the buffer zone. These effects are due almost entirely to the change in the Lagrangian integral timescale and are shown to be well represented in a first-order LS model by Sawford's correction footnote Sawford, B.L. 1991: Reynolds number effects in Lagrangian stochastic models of turbulent dispersion. Phys Fluids, 3, 1577-1586). This is found to remain true even when the Taylor-Reynolds number R_λ ~ O(0.1). This is somewhat surprising because the assumption of a Markovian evolution for velocity and position is strictly applicable only in the large Reynolds number limit because then the Lagrangian acceleration autocorrelation function approaches a delta function at the origin, corresponding to an uncorrelated component in the acceleration, and hence a Markov process footnote Borgas, M.S. and Sawford, B.L. 1991: The small-scale structure of acceleration correlations and its role in the statistical theory of turbulent dispersion. J. Fluid Mech. 288, 295-320.

22. SIDE WALL CONSTRUCTION, NORTH TRAINING WALL, LOOKING WEST FROM ...

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

22. SIDE WALL CONSTRUCTION, NORTH TRAINING WALL, LOOKING WEST FROM THE SAME POINT AS VIEW NO. 21. - Oakland Harbor Training Walls, Mouth of Federal Channel to Inner Harbor, Oakland, Alameda County, CA

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.

Micro-aerial vehicle type wall-climbing robot mechanism for structural health monitoring

NASA Astrophysics Data System (ADS)

Shin, Jae-Uk; Kim, Donghoon; Kim, Jong-Heon; Myung, Hyun

2013-04-01

Currently, the maintenance or inspection of large structures is labor-intensive, so it has a problem of the large cost due to the staffing professionals and the risk for hard to reach areas. To solve the problem, the needs of wall-climbing robot are emerged. Infra-based wall-climbing robots to maintain an outer wall of building have high payload and safety. However, the infrastructure for the robot must be equipped on the target structure and the infrastructure isn't preferred by the architects since it can injure the exterior of the structure. These are the reasons of why the infra-based wall-climbing robot is avoided. In case of the non-infra-based wall-climbing robot, it is researched to overcome the aforementioned problems. However, most of the technologies are in the laboratory level since the payload, safety and maneuverability are not satisfactory. For this reason, aerial vehicle type wall-climbing robot is researched. It is a flying possible wallclimbing robot based on a quadrotor. It is a famous aerial vehicle robot using four rotors to make a thrust for flying. This wall-climbing robot can stick to a vertical wall using the thrust. After sticking to the wall, it can move with four wheels installed on the robot. As a result, it has high maneuverability and safety since it can restore the position to the wall even if it is detached from the wall by unexpected disturbance while climbing the wall. The feasibility of the main concept was verified through simulations and experiments using a prototype.

Tandem accelerators in Romania: Multi-tools for science, education and technology

NASA Astrophysics Data System (ADS)

Burducea, I.; GhiÅ£ǎ, D. G.; Sava, T. B.; Straticiuc, M.

2017-06-01

An educated selection of the main beam parameters - particle type, velocity and intensity, can result in a cutting-edge scalpel to remove tumors, sanitize sewage, act as a nuclear forensics detective, date an artefact, clean up air, improve a microprocessor, transmute nuclear waste, detect a counterfeit or even look into the stars. Nowadays more than particle accelerators operate worldwide in medicine, industry and basic research. For example the proton therapy market is expected to attain 1 billion US per year in 2019 with almost 330 proton therapy rooms, while the annual market for the ion implantation industry already reached 1.5 G in revenue [1,2]. A brief history of the Tandem Accelerators Complex at IFIN-HH [3] emphasizing on their applications and the physics behind the scenes, is also presented [4-6].

PERFORMANCE VERIFICATION OF ANIMAL WATER TREATMENT TECHNOLOGIES THROUGH EPA'S ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM

EPA Science Inventory

The U.S. Environmental Protection Agency created the Environmental Technology Verification Program (ETV) to further environmental protection by accelerating the commercialization of new and innovative technology through independent performance verification and dissemination of in...

Break the "wall" and become creative: Enacting embodied metaphors in virtual reality.

PubMed

Wang, Xinyue; Lu, Kelong; Runco, Mark A; Hao, Ning

2018-07-01

This study investigated whether the experience of "breaking the walls", the embodiment of the metaphor "breaking the rules", could enhance creative performance. The virtual reality technology was used to simulate the scenario where participants could "break the walls" while walking in a corridor. Participants were asked to solve the creativity-demanding problems (ie., alternative uses tasks, AUT) in either the "break" condition in which they had to break the walls to move forward in VR, or the "no-break" condition where no barrier walls would appear. Results showed higher AUT originality and AUT fluency in the "break" condition than in the "no-break" condition. Moreover, the effects of "breaking the walls" on AUT originality were fully mediated by cognitive flexibility and persistence. These findings may indicate that enacting metaphors such as "breaking the rules" contribute to creative performance. The enhanced cognitive flexibility and persistence may account for the benefits. Copyright © 2018 Elsevier Inc. All rights reserved.

Overview of accelerators with potential use in homeland security

DOE PAGES

Garnett, Robert W.

2015-06-18

Quite a broad range of accelerators have been applied to solving many of the challenging problems related to homeland security and defense. These accelerator systems range from relatively small, simple, and compact, to large and complex, based on the specific application requirements. They have been used or proposed as sources of primary and secondary probe beams for applications such as radiography and to induce specific reactions that are key signatures for detecting conventional explosives or fissile material. A brief overview and description of these accelerator systems, their specifications, and application will be presented. Some recent technology trends will also bemore » discussed.« less

77 FR 59667 - NIJ Evaluation of Through-Wall Sensor Devices

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-28

..., Surveillance, and Biometric Technologies Center of Excellence (SSBT CoE). The evaluation is focused on field operation in civilian law enforcement scenarios. Supplied through-wall sensor devices must be fully certified by the Federal Communications Commission for domestic civilian law enforcement operation...

Wall Shear Stress, Wall Pressure and Near Wall Velocity Field Relationships in a Whirling Annular Seal

NASA Technical Reports Server (NTRS)

Morrison, Gerald L.; Winslow, Robert B.; Thames, H. Davis, III

1996-01-01

The mean and phase averaged pressure and wall shear stress distributions were measured on the stator wall of a 50% eccentric annular seal which was whirling in a circular orbit at the same speed as the shaft rotation. The shear stresses were measured using flush mounted hot-film probes. Four different operating conditions were considered consisting of Reynolds numbers of 12,000 and 24,000 and Taylor numbers of 3,300 and 6,600. At each of the operating conditions the axial distribution (from Z/L = -0.2 to 1.2) of the mean pressure, shear stress magnitude, and shear stress direction on the stator wall were measured. Also measured were the phase averaged pressure and shear stress. These data were combined to calculate the force distributions along the seal length. Integration of the force distributions result in the net forces and moments generated by the pressure and shear stresses. The flow field inside the seal operating at a Reynolds number of 24,000 and a Taylor number of 6,600 has been measured using a 3-D laser Doppler anemometer system. Phase averaged wall pressure and wall shear stress are presented along with phase averaged mean velocity and turbulence kinetic energy distributions located 0.16c from the stator wall where c is the seal clearance. The relationships between the velocity, turbulence, wall pressure and wall shear stress are very complex and do not follow simple bulk flow predictions.

Investigation of Plant Cell Wall Properties: A Study of Contributions from the Nanoscale to the Macroscale Impacting Cell Wall Recalcitrance

NASA Astrophysics Data System (ADS)

Crowe, Jacob Dillon

Biochemical conversion of lignocellulosic biomass to fuel ethanol is one of a few challenging, yet opportune technologies that can reduce the consumption of petroleum-derived transportation fuels, while providing parallel reductions in greenhouse gas emissions. Biomass recalcitrance, or resistance to deconstruction, is a major technical challenge that limits effective conversion of biomass to fermentable sugars, often requiring a costly thermochemical pretreatment step to improve biomass deconstruction. Biomass recalcitrance is imparted largely by the secondary cell wall, a complex polymeric matrix of cell wall polysaccharides and aromatic heteropolymers, that provides structural stability to cells and enables plant upright growth. Polymers within the cell wall can vary both compositionally and structurally depending upon plant species and anatomical fraction, and have varied responses to thermochemical pretreatments. Cell wall properties impacting recalcitrance are still not well understood, and as a result, the goal of this dissertation is to investigate structural features of the cell wall contributing to recalcitrance (1) in diverse anatomical fractions of a single species, (2) in response to diverse pretreatments, and (3) resulting from genetic modification. In the first study, feedstock cell wall heterogeneity was investigated in anatomical (stem, leaf sheaths, and leaf blades) and internode fractions of switchgrass at varying tissue maturities. Lignin content was observed as the key contributor to recalcitrance in maturing stem tissues only, with non-cellulosic substituted glucuronoarabinoxylans and pectic polysaccharides contributing to cell wall recalcitrance in leaf sheath and leaf blades. Hydroxycinnamate (i.e., saponifiable p-coumarate and ferulate) content along with xylan and pectin extractability decreased with tissue maturity, suggesting lignification is only one component imparting maturity specific cell wall recalcitrance. In the second study

Chest-wall reconstruction with a customized titanium-alloy prosthesis fabricated by 3D printing and rapid prototyping.

PubMed

Wen, Xiaopeng; Gao, Shan; Feng, Jinteng; Li, Shuo; Gao, Rui; Zhang, Guangjian

2018-01-08

As 3D printing technology emerge, there is increasing demand for a more customizable implant in the repair of chest-wall bony defects. This article aims to present a custom design and fabrication method for repairing bony defects of the chest wall following tumour resection, which utilizes three-dimensional (3D) printing and rapid-prototyping technology. A 3D model of the bony defect was generated after acquiring helical CT data. A customized prosthesis was then designed using computer-aided design (CAD) and mirroring technology, and fabricated using titanium-alloy powder. The mechanical properties of the printed prosthesis were investigated using ANSYS software. The yield strength of the titanium-alloy prosthesis was 950 ± 14 MPa (mean ± SD), and its ultimate strength was 1005 ± 26 MPa. The 3D finite element analyses revealed that the equivalent stress distribution of each prosthesis was unifrom. The symmetry and reconstruction quality contour of the repaired chest wall was satisfactory. No rejection or infection occurred during the 6-month follow-up period. Chest-wall reconstruction with a customized titanium-alloy prosthesis is a reliable technique for repairing bony defects.

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

Experimental investigation of compliant wall surface deformation in a turbulent channel flow

NASA Astrophysics Data System (ADS)

Zhang, Cao; Wang, Jin; Katz, Joseph

2016-11-01

The dynamic response of a compliant wall under a turbulent channel flow is investigated by simultaneously measuring the time-resolved, 3D flow field (using tomographic PIV) and the 2D surface deformation (using interferometry). The pressure distributions are calculated by spatially integrating the material acceleration field. The Reynolds number is Reτ = 2300, and the centerline velocity (U0) is 15% of the material shear speed. The wavenumber-frequency spectra of the wall deformation contain a non-advected low-frequency component and advected modes, some traveling downstream at U0 and others at 0.72U0. Trends in the wall dynamics are elucidated by correlating the deformation with flow variables. The spatial pressure-deformation correlations peak at y/ h 0.12 (h is half channel height), the elevation of Reynolds shear stress maximum in the log-layer. Streamwise lagging of the deformation behind the pressure is caused in part by phase-lag of the pressure with decreasing distance from the wall, and in part by material damping. Positive deformations (bumps) are preferentially associated with ejections, which involve spanwise vortices located downstream and quasi-streamwise vortices with spanwise offset, consistent with hairpin-like structures. The negative deformations (dents) are preferentially associated with pressure maxima at the transition between an upstream sweep to a downstream ejection. Sponsored by ONR.

Accelerated stress testing of terrestrial solar cells

NASA Technical Reports Server (NTRS)

Prince, J. L.; Lathrop, J. W.

1979-01-01

A program to investigate the reliability characteristics of unencapsulated low-cost terrestrial solar cells using accelerated stress testing is described. Reliability (or parametric degradation) factors appropriate to the cell technologies and use conditions were studied and a series of accelerated stress tests was synthesized. An electrical measurement procedure and a data analysis and management system was derived, and stress test fixturing and material flow procedures were set up after consideration was given to the number of cells to be stress tested and measured and the nature of the information to be obtained from the process. Selected results and conclusions are presented.

Electron-Beam Dynamics for an Advanced Flash-Radiography Accelerator

DOE PAGES

Ekdahl, Carl

2015-11-17

Beam dynamics issues were assessed for a new linear induction electron accelerator being designed for multipulse flash radiography of large explosively driven hydrodynamic experiments. Special attention was paid to equilibrium beam transport, possible emittance growth, and beam stability. Especially problematic would be high-frequency beam instabilities that could blur individual radiographic source spots, low-frequency beam motion that could cause pulse-to-pulse spot displacement, and emittance growth that could enlarge the source spots. Furthermore, beam physics issues were examined through theoretical analysis and computer simulations, including particle-in-cell codes. Beam instabilities investigated included beam breakup, image displacement, diocotron, parametric envelope, ion hose, and themore » resistive wall instability. The beam corkscrew motion and emittance growth from beam mismatch were also studied. It was concluded that a beam with radiographic quality equivalent to the present accelerators at Los Alamos National Laboratory will result if the same engineering standards and construction details are upheld.« less

Humidity Distributions in Multilayered Walls of High-rise Buildings

NASA Astrophysics Data System (ADS)

Gamayunova, Olga; Musorina, Tatiana; Ishkov, Alexander

2018-03-01

The limitation of free territories in large cities is the main reason for the active development of high-rise construction. Given the large-scale projects of high-rise buildings in recent years in Russia and abroad and their huge energy consumption, one of the fundamental principles in the design and reconstruction is the use of energy-efficient technologies. The main heat loss in buildings occurs through enclosing structures. However, not always the heat-resistant wall will be energy-efficient and dry at the same time (perhaps waterlogging). Temperature and humidity distributions in multilayer walls were studied in the paper, and the interrelation of other thermophysical characteristics was analyzed.

Compact and tunable focusing device for plasma wakefield acceleration

NASA Astrophysics Data System (ADS)

Pompili, R.; Anania, M. P.; Chiadroni, E.; Cianchi, A.; Ferrario, M.; Lollo, V.; Notargiacomo, A.; Picardi, L.; Ronsivalle, C.; Rosenzweig, J. B.; Shpakov, V.; Vannozzi, A.

2018-03-01

Plasma wakefield acceleration, either driven by ultra-short laser pulses or electron bunches, represents one of the most promising techniques able to overcome the limits of conventional RF technology and allows the development of compact accelerators. In the particle beam-driven scenario, ultra-short bunches with tiny spot sizes are required to enhance the accelerating gradient and preserve the emittance and energy spread of the accelerated bunch. To achieve such tight transverse beam sizes, a focusing system with short focal length is mandatory. Here we discuss the development of a compact and tunable system consisting of three small-bore permanent-magnet quadrupoles with 520 T/m field gradient. The device has been designed in view of the plasma acceleration experiments planned at the SPARC_LAB test-facility. Being the field gradient fixed, the focusing is adjusted by tuning the relative position of the three magnets with nanometer resolution. Details about its magnetic design, beam-dynamics simulations, and preliminary results are examined in the paper.

5. Detail of bin wall, showing the thinner exterior wall ...

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

5. Detail of bin wall, showing the thinner exterior wall next to the inner wall with its alternating courses of channel tile and hollow tile. - Saint Anthony Elevator No. 3, 620 Malcom Avenue, Southeast, Minneapolis, Hennepin County, MN

Study of Corona Discharge on 160 KeV, 10 mA Electron Accelerator Facility Using FEM

NASA Astrophysics Data System (ADS)

Ghazali, Abu Bakar Mhd; Sobri, Rokiah Mohd

2008-05-01

This paper describes a method to verify the overall design of our electron accelerator. It is free from corona or spark discharge phenomenon. This locally designed electron accelerator facility is located at Nuclear Malaysia Complex, Bangi, Selangor. In this study, we describe the geometry of the pressure vessel filled with SF6 gas at 2 atm to enclose the high voltage area of the accelerating tube. The Poisson's equation is used to calculate the contours of the electric field that is created between the cathode of -160 kV maximum and the wall of the vessel. The nearest sharp edge between the cathode and the pressure wall is 163 mm apart. The calculation is based on finite element method (FEM) for electrostatic charges in order to obtain an electric field contour in two-dimensional plane. We found that the surface charge density of the cathode is 1.1×10-5 C/m2 for the corona glowing seen at -90 kV. Moreover, the highest electric field near to (about 5 mm from) the sharp edge is about 2.7 MV/m, which is less than the dielectric strength of SF6 gas, i.e. 6 MV/m and therefore, it proved that our design of the pressure vessel is save from corona or spark discharges.

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT - PORTABLE GAS CHROMATOGRAPH ELECTRONIC SENSOR TECHNOLOGY MODEL 4100

EPA Science Inventory

The U.S. Environmental Protection Agency, through the Environmental Technology Verification Program, is working to accelerate the acceptance and use of innovative technologies that improve the way the United States manages its environmental problems. As part of this program, the...

3D Resistive MHD Simulations of Formation, Compression, and Acceleration of Compact Tori

NASA Astrophysics Data System (ADS)

Woodruff, Simon; Meyer, Thomas; Stuber, James; Romero-Talamas, Carlos; Brown, Michael; Kaur, Manjit; Schaffner, David

2017-10-01

We present results from extended resistive 3D MHD simulations (NIMROD) pertaining to a new formation method for toroidal plasmas using a reconnection region that forms in a radial implosion, and results from the acceleration of CTs along a drift tube that are accelerated by a coil and are allowed to go tilt unstable and form a helical minimum energy state. The new formation method results from a reconnection region that is generated between two magnetic compression coils that are ramped to 320kV in 2 μs. When the compressing field is aligned anti-parallel to a pre-existing CT, a current sheet and reconnection region forms that accelerates plasma radially inwards up to 500km/s which stagnates and directed energy converts to thermal, raising temperatures to 500eV. When field is aligned parallel to the pre-existing CT, the configuration can be accelerated along a drift tube. For certain ratios of magnetic field to density, the CT goes tilt-unstable forming a twisted flux rope, which can also be accelerated and stagnated on an end wall, where temperature and field increases as the plasma compresses. We compare simulation results with adiabatic scaling relations. Work supported by ARPA-E ALPHA program and DARPA.

Association Mapping of Cell Wall Synthesis Regulatory Genes and Cell Wall Quality in Switchgrass

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

Bartley, Laura; Wu, Y.; Zhu, L.

project provides specific targets for future engineering of switchgrass cell wall regulation and may also facilitate identification of regulators that underlie the molecular markers that are genetically linked to differences in cell wall quality. With the goal of spurring further research and technological developments in lignocellulosic biofuel production, this work has been communicated to the bioenergy and cell wall communities though various presentations and publications. To date, three manuscripts have been published, two others are near to publication, three others are in an advanced state, and two to four more are likely to be written based on analyses still in progress. In addition, project participants have presented thirteen posters and talks at regional, national, and international meetings about aspects of this project. In sum, the work supported by this funding has made and communicated significant progress in identifying the genes that grasses use for cell wall synthesis and regulation, information that will be used by project participants and others to improve the efficiency of conversion of lignocellulosic biomass to biofuels.« less

Classical and quantum localization and delocalization in the Fermi accelerator, kicked rotor and two-sided kicked rotor models

NASA Astrophysics Data System (ADS)

Zaslavsky, M.

1996-06-01

The phenomena of dynamical localization, both classical and quantum, are studied in the Fermi accelerator model. The model consists of two vertical oscillating walls and a ball bouncing between them. The classical localization boundary is calculated in the case of ``sinusoidal velocity transfer'' [A. J. Lichtenberg and M. A. Lieberman, Regular and Stochastic Motion (Springer-Verlag, Berlin, 1983)] on the basis of the analysis of resonances. In the case of the ``sawtooth'' wall velocity we show that the quantum localization is determined by the analytical properties of the canonical transformations to the action and angle coordinates of the unperturbed Hamiltonian, while the existence of the classical localization is determined by the number of continuous derivatives of the distance between the walls with respect to time.

An Experimental Study of a Low-Jitter Pulsed Electromagnetic Plasma Accelerator

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Lee, Michael; Eskridge, Richard; Smith, James; Martin, Adam; Rodgers, Stephen L. (Technical Monitor)

2001-01-01

An experimental plasma accelerator for a variety of applications under development at the NASA Marshall Space Flight Center is described. The accelerator is a pulsed plasma thruster and has been tested experimentally and plasma jet velocities of approximately 50 kilometers per second have been obtained. The plasma jet structure has been photographed with 10 ns exposure times to reveal a stable and repeatable plasma structure. Data for velocity profile information has been obtained using light pipes embedded in the gun walls to record the plasma transit at various barrel locations. Preliminary spatially resolved spectral data and magnetic field probe data are also presented. A high speed triggering system has been developed and tested as a means of reducing the gun "jitter". This jitter has been characterized and future work for second generation "ultra-low jitter" gun development is identified.

25. NORTH TRAINING WALL, EAST SECTION, SIDE WALL CONSTRUCTION, LOOKING ...

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

25. NORTH TRAINING WALL, EAST SECTION, SIDE WALL CONSTRUCTION, LOOKING WEST FROM A POINT ABOUT 500 FEET FROM THE MIDDLE HARBOR PARK FISHING PIER. (Panoramic view 1 of 2). - Oakland Harbor Training Walls, Mouth of Federal Channel to Inner Harbor, Oakland, Alameda County, CA

Thermionic Emission of Single-Wall Carbon Nanotubes Measured

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Krainsky, Isay L.; Bailey, Sheila G.; Elich, Jeffrey M.; Landi, Brian J.; Gennett, Thomas; Raffaelle, Ryne P.

2004-01-01

Researchers at the NASA Glenn Research Center, in collaboration with the Rochester Institute of Technology, have investigated the thermionic properties of high-purity, single-wall carbon nanotubes (SWNTs) for use as electron-emitting electrodes. Carbon nanotubes are a recently discovered material made from carbon atoms bonded into nanometer-scale hollow tubes. Such nanotubes have remarkable properties. An extremely high aspect ratio, as well as unique mechanical and electronic properties, make single-wall nanotubes ideal for use in a vast array of applications. Carbon nanotubes typically have diameters on the order of 1 to 2 nm. As a result, the ends have a small radius of curvature. It is these characteristics, therefore, that indicate they might be excellent potential candidates for both thermionic and field emission.

Compilation of accelerated bridge construction (ABC) bridges : final report.

DOT National Transportation Integrated Search

2016-01-01

Development of accelerated bridge construction (ABC) technologies has been occurring across the country, many times in : isolation. Although FHWA and others have worked to facilitate communication between these efforts, there was not a : comprehensiv...

Thomas Jefferson National Accelerator Facility

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

Grames, Joseph; Higinbotham, Douglas; Montgomery, Hugh

The Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia, USA, is one of ten national laboratories under the aegis of the Office of Science of the U.S. Department of Energy (DOE). It is managed and operated by Jefferson Science Associates, LLC. The primary facility at Jefferson Lab is the Continuous Electron Beam Accelerator Facility (CEBAF) as shown in an aerial photograph in Figure 1. Jefferson Lab was created in 1984 as CEBAF and started operations for physics in 1995. The accelerator uses superconducting radio-frequency (srf) techniques to generate high-quality beams of electrons with high-intensity, well-controlled polarization. Themore » technology has enabled ancillary facilities to be created. The CEBAF facility is used by an international user community of more than 1200 physicists for a program of exploration and study of nuclear, hadronic matter, the strong interaction and quantum chromodynamics. Additionally, the exceptional quality of the beams facilitates studies of the fundamental symmetries of nature, which complement those of atomic physics on the one hand and of high-energy particle physics on the other. The facility is in the midst of a project to double the energy of the facility and to enhance and expand its experimental facilities. Studies are also pursued with a Free-Electron Laser produced by an energy-recovering linear accelerator.« less

Free electron lasers driven by linear induction accelerators: High power radiation sources

NASA Technical Reports Server (NTRS)

Orzechowski, T. J.

1989-01-01

The technology of Free Electron Lasers (FELs) and linear induction accelerators (LIAs) is addressed by outlining the following topics: fundamentals of FELs; basic concepts of linear induction accelerators; the Electron Laser Facility (a microwave FEL); PALADIN (an infrared FEL); magnetic switching; IMP; and future directions (relativistic klystrons). This presentation is represented by viewgraphs only.

HF Accelerated Electron Fluxes, Spectra, and Ionization

NASA Astrophysics Data System (ADS)

Carlson, Herbert C.; Jensen, Joseph B.

2015-10-01

Wave particle interactions, an essential aspect of laboratory, terrestrial, and astrophysical plasmas, have been studied for decades by transmitting high power HF radio waves into Earth's weakly ionized space plasma, to use it as a laboratory without walls. Application to HF electron acceleration remains an active area of research (Gurevich in Usp Fizicheskikh Nauk 177(11):1145-1177, 2007) today. HF electron acceleration studies began when plasma line observations proved (Carlson et al. in J Atmos Terr Phys 44:1089-1100, 1982) that high power HF radio wave-excited processes accelerated electrons not to ~eV, but instead to -100 times thermal energy (10 s of eV), as a consequence of inelastic collision effects on electron transport. Gurevich et al (J Atmos Terr Phys 47:1057-1070, 1985) quantified the theory of this transport effect. Merging experiment with theory in plasma physics and aeronomy, enabled prediction (Carlson in Adv Space Res 13:1015-1024, 1993) of creating artificial ionospheres once ~GW HF effective radiated power could be achieved. Eventual confirmation of this prediction (Pedersen et al. in Geophys Res Lett 36:L18107, 2009; Pedersen et al. in Geophys Res Lett 37:L02106, 2010; Blagoveshchenskaya et al. in Ann Geophys 27:131-145, 2009) sparked renewed interest in optical inversion to estimate electron spectra in terrestrial (Hysell et al. in J Geophys Res Space Phys 119:2038-2045, 2014) and planetary (Simon et al. in Ann Geophys 29:187-195, 2011) atmospheres. Here we present our unpublished optical data, which combined with our modeling, lead to conclusions that should meaningfully improve future estimates of the spectrum of HF accelerated electron fluxes. Photometric imaging data can significantly improve detection of emissions near ionization threshold, and confirm depth of penetration of accelerated electrons many km below the excitation altitude. Comparing observed to modeled emission altitude shows future experiments need electron density profiles

Identifying new technologies that save energy and reduce costs to the Federal sector: The New Technology Program

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

Hunt, W.D.M.; Conover, D.R.; Stockmeyer, M.K.

1995-11-01

In 1990 the New Technology Demonstration Program (formerly the Test Bed Demonstration Program) was initiated by the US Department of Energy`s Office (DOE`s) of Federal Energy Management Programs with the purpose of accelerating the introduction of new technologies into the Federal sector. The program has since expanded into a multi-laboratory collaborative effort that evaluates new technologies and shares the results with the Federal design and procurement communities. These evaluations are performed on a collaborative basis which typically includes technology manufacturers, Federal facilities, utilities, trade associations, research institutes, and other in partnership with DOE. The end result is a range ofmore » effective technology transfer tools that provide operations and performance data on new technologies to Federal designers, building managers, and procurement officials. These tools assist in accelerating a technology`s Federal application and realizing reductions in energy consumption and costs.« less

Accelerated Adaptive MGS Phase Retrieval

NASA Technical Reports Server (NTRS)

Lam, Raymond K.; Ohara, Catherine M.; Green, Joseph J.; Bikkannavar, Siddarayappa A.; Basinger, Scott A.; Redding, David C.; Shi, Fang

2011-01-01

The Modified Gerchberg-Saxton (MGS) algorithm is an image-based wavefront-sensing method that can turn any science instrument focal plane into a wavefront sensor. MGS characterizes optical systems by estimating the wavefront errors in the exit pupil using only intensity images of a star or other point source of light. This innovative implementation of MGS significantly accelerates the MGS phase retrieval algorithm by using stream-processing hardware on conventional graphics cards. Stream processing is a relatively new, yet powerful, paradigm to allow parallel processing of certain applications that apply single instructions to multiple data (SIMD). These stream processors are designed specifically to support large-scale parallel computing on a single graphics chip. Computationally intensive algorithms, such as the Fast Fourier Transform (FFT), are particularly well suited for this computing environment. This high-speed version of MGS exploits commercially available hardware to accomplish the same objective in a fraction of the original time. The exploit involves performing matrix calculations in nVidia graphic cards. The graphical processor unit (GPU) is hardware that is specialized for computationally intensive, highly parallel computation. From the software perspective, a parallel programming model is used, called CUDA, to transparently scale multicore parallelism in hardware. This technology gives computationally intensive applications access to the processing power of the nVidia GPUs through a C/C++ programming interface. The AAMGS (Accelerated Adaptive MGS) software takes advantage of these advanced technologies, to accelerate the optical phase error characterization. With a single PC that contains four nVidia GTX-280 graphic cards, the new implementation can process four images simultaneously to produce a JWST (James Webb Space Telescope) wavefront measurement 60 times faster than the previous code.

Evaluation of marginal gap of Ni-Cr copings made with conventional and accelerated casting techniques.

PubMed

Tannamala, Pavan Kumar; Azhagarasan, Nagarasampatti Sivaprakasam; Shankar, K Chitra

2013-01-01

Conventional casting techniques following the manufacturers' recommendations are time consuming. Accelerated casting techniques have been reported, but their accuracy with base metal alloys has not been adequately studied. We measured the vertical marginal gap of nickel-chromium copings made by conventional and accelerated casting techniques and determined the clinical acceptability of the cast copings in this study. Experimental design, in vitro study, lab settings. Ten copings each were cast by conventional and accelerated casting techniques. All copings were identical, only their mold preparation schedules differed. Microscopic measurements were recorded at ×80 magnification on the perpendicular to the axial wall at four predetermined sites. The marginal gap values were evaluated by paired t test. The mean marginal gap by conventional technique (34.02 μm) is approximately 10 μm lesser than that of accelerated casting technique (44.62 μm). As the P value is less than 0.0001, there is highly significant difference between the two techniques with regard to vertical marginal gap. The accelerated casting technique is time saving and the marginal gap measured was within the clinically acceptable limits and could be an alternative to time-consuming conventional techniques.

Simulation Studies of the Dielectric Grating as an Accelerating and Focusing Structure

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

Soong, Ken; Peralta, E.A.; Byer, R.L.

A grating-based design is a promising candidate for a laser-driven dielectric accelerator. Through simulations, we show the merits of a readily fabricated grating structure as an accelerating component. Additionally, we show that with a small design perturbation, the accelerating component can be converted into a focusing structure. The understanding of these two components is critical in the successful development of any complete accelerator. The concept of accelerating electrons with the tremendous electric fields found in lasers has been proposed for decades. However, until recently the realization of such an accelerator was not technologically feasible. Recent advances in the semiconductor industry,more » as well as advances in laser technology, have now made laser-driven dielectric accelerators imminent. The grating-based accelerator is one proposed design for a dielectric laser-driven accelerator. This design, which was introduced by Plettner, consists of a pair of opposing transparent binary gratings, illustrated in Fig. 1. The teeth of the gratings serve as a phase mask, ensuring a phase synchronicity between the electromagnetic field and the moving particles. The current grating accelerator design has the drive laser incident perpendicular to the substrate, which poses a laser-structure alignment complication. The next iteration of grating structure fabrication seeks to monolithically create an array of grating structures by etching the grating's vacuum channel into a fused silica wafer. With this method it is possible to have the drive laser confined to the plane of the wafer, thus ensuring alignment of the laser-and-structure, the two grating halves, and subsequent accelerator components. There has been previous work using 2-dimensional finite difference time domain (2D-FDTD) calculations to evaluate the performance of the grating accelerator structure. However, this work approximates the grating as an infinite structure and does not accurately model a

"The Most Poisonous Force in Technology"

ERIC Educational Resources Information Center

Carnevale, Dan

2007-01-01

Walt Mossberg, personal-technology columnist for "The Wall Street Journal," highlighted technology trends in his speech to a group of college presidents and other administrators. Mr. Mossberg touched a nerve when he called information-technology departments of large organizations, including colleges, "the most regressive and poisonous force in…

StegoWall: blind statistical detection of hidden data

NASA Astrophysics Data System (ADS)

Voloshynovskiy, Sviatoslav V.; Herrigel, Alexander; Rytsar, Yuri B.; Pun, Thierry

2002-04-01

Novel functional possibilities, provided by recent data hiding technologies, carry out the danger of uncontrolled (unauthorized) and unlimited information exchange that might be used by people with unfriendly interests. The multimedia industry as well as the research community recognize the urgent necessity for network security and copyright protection, or rather the lack of adequate law for digital multimedia protection. This paper advocates the need for detecting hidden data in digital and analog media as well as in electronic transmissions, and for attempting to identify the underlying hidden data. Solving this problem calls for the development of an architecture for blind stochastic hidden data detection in order to prevent unauthorized data exchange. The proposed architecture is called StegoWall; its key aspects are the solid investigation, the deep understanding, and the prediction of possible tendencies in the development of advanced data hiding technologies. The basic idea of our complex approach is to exploit all information about hidden data statistics to perform its detection based on a stochastic framework. The StegoWall system will be used for four main applications: robust watermarking, secret communications, integrity control and tamper proofing, and internet/network security.

Spin-orbit-torque-induced magnetic domain wall motion in Ta/CoFe nanowires with sloped perpendicular magnetic anisotropy.

PubMed

Zhang, Yue; Luo, Shijiang; Yang, Xiaofei; Yang, Chang

2017-05-17

In materials with the gradient of magnetic anisotropy, spin-orbit-torque-induced magnetization behaviour has attracted attention because of its intriguing scientific principle and potential application. Most of the magnetization behaviours microscopically originate from magnetic domain wall motion, which can be precisely depicted using the standard cooperative coordinate method (CCM). However, the domain wall motion in materials with the gradient of magnetic anisotropy using the CCM remains lack of investigation. In this paper, by adopting CCM, we established a set of equations to quantitatively depict the spin-orbit-torque-induced motion of domain walls in a Ta/CoFe nanotrack with weak Dzyaloshinskii-Moriya interaction and magnetic anisotropy gradient. The equations were solved numerically, and the solutions are similar to those of a micromagnetic simulation. The results indicate that the enhanced anisotropy along the track acts as a barrier to inhibit the motion of the domain wall. In contrast, the domain wall can be pushed to move in a direction with reduced anisotropy, with the velocity being accelerated by more than twice compared with that for the constant anisotropy case. This substantial velocity manipulation by anisotropy engineering is important in designing novel magnetic information devices with high reading speeds.

Conceptual design of divertor and first wall for DEMO-FNS

NASA Astrophysics Data System (ADS)

Sergeev, V. Yu.; Kuteev, B. V.; Bykov, A. S.; Gervash, A. A.; Glazunov, D. A.; Goncharov, P. R.; Dnestrovskij, A. Yu.; Khayrutdinov, R. R.; Klishchenko, A. V.; Lukash, V. E.; Mazul, I. V.; Molchanov, P. A.; Petrov, V. S.; Rozhansky, V. A.; Shpanskiy, Yu. S.; Sivak, A. B.; Skokov, V. G.; Spitsyn, A. V.

2015-11-01

Key issues of design of the divertor and the first wall of DEMO-FNS are presented. A double null closed magnetic configuration was chosen with long external legs and V-shaped corners. The divertor employs a cassette design similar to that of ITER. Water-cooled first wall of the tokamak is made of Be tiles and CuCrZr-stainless steel shells. Lithium injection and circulation technologies are foreseen for protection of plasma facing components. Simulations of thermal loads onto the first wall and divertor plates suggest a possibility to distribute heat loads making them less than 10 MW m-2. Evaluations of sputtering and evaporation of plasma-facing materials suggest that lithium may protect the first wall. To prevent Be erosion at the outer divertor plates either the full detached divertor operation or arrangement of the renewal lithium flow on targets should be implemented. Test bed experiments on the Tsefey-M facility with the first wall mockup coated by Ве tiles and cooled by water are presented. The temperature of the surface of tiles reached 280-300 °С at 5 MW m-2 and 600-650 °С at 10.5 MW m-2. The mockup successfully withstood 1000 cycles with the lower thermal loading and 100 cycles with higher thermal loading.

Characterization of the radiation environment at the UNLV accelerator facility during operation of the Varian M6 linac

NASA Astrophysics Data System (ADS)

Hodges, M.; Barzilov, A.; Chen, Y.; Lowe, D.

2016-10-01

The bremsstrahlung photon flux from the UNLV particle accelerator (Varian M6 model) was determined using MCNP5 code for 3 MeV and 6 MeV incident electrons. Human biological equivalent dose rates due to accelerator operation were evaluated using the photon flux with the flux-to-dose conversion factors. Dose rates were computed for the accelerator facility for M6 linac use under different operating conditions. The results showed that the use of collimators and linac internal shielding significantly reduced the dose rates throughout the facility. It was shown that the walls of the facility, in addition to the earthen berm enveloping the building, provide equivalent shielding to reduce dose rates outside to below the 2 mrem/h limit.

Converging blockchain and next-generation artificial intelligence technologies to decentralize and accelerate biomedical research and healthcare

PubMed Central

Mamoshina, Polina; Ojomoko, Lucy; Yanovich, Yury; Ostrovski, Alex; Botezatu, Alex; Prikhodko, Pavel; Izumchenko, Eugene; Aliper, Alexander; Romantsov, Konstantin; Zhebrak, Alexander; Ogu, Iraneus Obioma; Zhavoronkov, Alex

2018-01-01

The increased availability of data and recent advancements in artificial intelligence present the unprecedented opportunities in healthcare and major challenges for the patients, developers, providers and regulators. The novel deep learning and transfer learning techniques are turning any data about the person into medical data transforming simple facial pictures and videos into powerful sources of data for predictive analytics. Presently, the patients do not have control over the access privileges to their medical records and remain unaware of the true value of the data they have. In this paper, we provide an overview of the next-generation artificial intelligence and blockchain technologies and present innovative solutions that may be used to accelerate the biomedical research and enable patients with new tools to control and profit from their personal data as well with the incentives to undergo constant health monitoring. We introduce new concepts to appraise and evaluate personal records, including the combination-, time- and relationship-value of the data. We also present a roadmap for a blockchain-enabled decentralized personal health data ecosystem to enable novel approaches for drug discovery, biomarker development, and preventative healthcare. A secure and transparent distributed personal data marketplace utilizing blockchain and deep learning technologies may be able to resolve the challenges faced by the regulators and return the control over personal data including medical records back to the individuals. PMID:29464026

Converging blockchain and next-generation artificial intelligence technologies to decentralize and accelerate biomedical research and healthcare.

PubMed

Mamoshina, Polina; Ojomoko, Lucy; Yanovich, Yury; Ostrovski, Alex; Botezatu, Alex; Prikhodko, Pavel; Izumchenko, Eugene; Aliper, Alexander; Romantsov, Konstantin; Zhebrak, Alexander; Ogu, Iraneus Obioma; Zhavoronkov, Alex

2018-01-19

The increased availability of data and recent advancements in artificial intelligence present the unprecedented opportunities in healthcare and major challenges for the patients, developers, providers and regulators. The novel deep learning and transfer learning techniques are turning any data about the person into medical data transforming simple facial pictures and videos into powerful sources of data for predictive analytics. Presently, the patients do not have control over the access privileges to their medical records and remain unaware of the true value of the data they have. In this paper, we provide an overview of the next-generation artificial intelligence and blockchain technologies and present innovative solutions that may be used to accelerate the biomedical research and enable patients with new tools to control and profit from their personal data as well with the incentives to undergo constant health monitoring. We introduce new concepts to appraise and evaluate personal records, including the combination-, time- and relationship-value of the data. We also present a roadmap for a blockchain-enabled decentralized personal health data ecosystem to enable novel approaches for drug discovery, biomarker development, and preventative healthcare. A secure and transparent distributed personal data marketplace utilizing blockchain and deep learning technologies may be able to resolve the challenges faced by the regulators and return the control over personal data including medical records back to the individuals.

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.

Products Released from Enzymically Active Cell Wall Stimulate Ethylene Production and Ripening in Preclimacteric Tomato (Lycopersicon esculentum Mill.) Fruit 1