Hypersonic Magneto-Fluid-Dynamic Compression in Cylindrical Inlet

NASA Technical Reports Server (NTRS)

Shang, Joseph S.; Chang, Chau-Lyan

2007-01-01

Hypersonic magneto-fluid-dynamic interaction has been successfully performed as a virtual leading-edge strake and a virtual cowl of a cylindrical inlet. In a side-by-side experimental and computational study, the magnitude of the induced compression was found to be depended on configuration and electrode placement. To better understand the interacting phenomenon the present investigation is focused on a direct current discharge at the leading edge of a cylindrical inlet for which validating experimental data is available. The present computational result is obtained by solving the magneto-fluid-dynamics equations at the low magnetic Reynolds number limit and using a nonequilibrium weakly ionized gas model based on the drift-diffusion theory. The numerical simulation provides a detailed description of the intriguing physics. After validation with experimental measurements, the computed results further quantify the effectiveness of a magnet-fluid-dynamic compression for a hypersonic cylindrical inlet. At a minuscule power input to a direct current surface discharge of 8.14 watts per square centimeter of electrode area produces an additional compression of 6.7 percent for a constant cross-section cylindrical inlet.

Results of the Sea Ice Model Intercomparison Project: Evaluation of sea ice rheology schemes for use in climate simulations

NASA Astrophysics Data System (ADS)

Kreyscher, Martin; Harder, Markus; Lemke, Peter; Flato, Gregory M.

2000-05-01

A hierarchy of sea ice rheologies is evaluated on the basis of a comprehensive set of observational data. The investigations are part of the Sea Ice Model Intercomparison Project (SIMIP). Four different sea ice rheology schemes are compared: a viscous-plastic rheology, a cavitating-fluid model, a compressible Newtonian fluid, and a simple free drift approach with velocity correction. The same grid, land boundaries, and forcing fields are applied to all models. As verification data, there are (1) ice thickness data from upward looking sonars (ULS), (2) ice concentration data from the passive microwave radiometers SMMR and SSM/I, (3) daily buoy drift data obtained by the International Arctic Buoy Program (IABP), and (4) satellite-derived ice drift fields based on the 85 GHz channel of SSM/I. All models are optimized individually with respect to mean drift speed and daily drift speed statistics. The impact of ice strength on the ice cover is best revealed by the spatial pattern of ice thickness, ice drift on different timescales, daily drift speed statistics, and the drift velocities in Fram Strait. Overall, the viscous-plastic rheology yields the most realistic simulation. In contrast, the results of the very simple free-drift model with velocity correction clearly show large errors in simulated ice drift as well as in ice thicknesses and ice export through Fram Strait compared to observation. The compressible Newtonian fluid cannot prevent excessive ice thickness buildup in the central Arctic and overestimates the internal forces in Fram Strait. Because of the lack of shear strength, the cavitating-fluid model shows marked differences to the statistics of observed ice drift and the observed spatial pattern of ice thickness. Comparison of required computer resources demonstrates that the additional cost for the viscous-plastic sea ice rheology is minor compared with the atmospheric and oceanic model components in global climate simulations.

Fluffy dust forms icy planetesimals by static compression

NASA Astrophysics Data System (ADS)

Kataoka, Akimasa; Tanaka, Hidekazu; Okuzumi, Satoshi; Wada, Koji

2013-09-01

Context. Several barriers have been proposed in planetesimal formation theory: bouncing, fragmentation, and radial drift problems. Understanding the structure evolution of dust aggregates is a key in planetesimal formation. Dust grains become fluffy by coagulation in protoplanetary disks. However, once they are fluffy, they are not sufficiently compressed by collisional compression to form compact planetesimals. Aims: We aim to reveal the pathway of dust structure evolution from dust grains to compact planetesimals. Methods: Using the compressive strength formula, we analytically investigate how fluffy dust aggregates are compressed by static compression due to ram pressure of the disk gas and self-gravity of the aggregates in protoplanetary disks. Results: We reveal the pathway of the porosity evolution from dust grains via fluffy aggregates to form planetesimals, circumventing the barriers in planetesimal formation. The aggregates are compressed by the disk gas to a density of 10-3 g/cm3 in coagulation, which is more compact than is the case with collisional compression. Then, they are compressed more by self-gravity to 10-1 g/cm3 when the radius is 10 km. Although the gas compression decelerates the growth, the aggregates grow rapidly enough to avoid the radial drift barrier when the orbital radius is ≲6 AU in a typical disk. Conclusions: We propose a fluffy dust growth scenario from grains to planetesimals. It enables icy planetesimal formation in a wide range beyond the snowline in protoplanetary disks. This result proposes a concrete initial condition of planetesimals for the later stages of the planet formation.

Modeling Drift Compression in an Integrated Beam Experiment for Heavy-Ion-Fusion

NASA Astrophysics Data System (ADS)

Sharp, W. M.; Barnard, J. J.; Friedman, A.; Grote, D. P.; Celata, C. M.; Yu, S. S.

2003-10-01

The Integrated Beam Experiment (IBX) is an induction accelerator being designed to further develop the science base for heavy-ion fusion. The experiment is being developed jointly by Lawrence Berkeley National Laboratory, Lawrence Livermore National Laboratory, and Princeton Plasma Physics Laboratory. One conceptual approach would first accelerate a 0.5-1 A beam of singly charged potassium ions to 5 MeV, impose a head-to-tail velocity tilt to compress the beam longitudinally, and finally focus the beam radiallly using a series of quadrupole lenses. The lengthwise compression is a critical step because the radial size must be controlled as the current increases, and the beam emittance must be kept minimal. The work reported here first uses the moment-based model HERMES to design the drift-compression beam line and to assess the sensitivity of the final beam profile to beam and lattice errors. The particle-in-cell code WARP is then used to validate the physics design, study the phase-space evolution, and quantify the emittance growth.

Small-scale lacustrine drifts in Lake Champlain, Vermont

USGS Publications Warehouse

Manley, Patricia L.; Manley, T.O.; Hayo, Kathryn; Cronin, Thomas

2012-01-01

High resolution CHIRP (Compressed High Intensity Radar Pulse) seismic profiles reveal the presence of two lacustrine sediment drifts located in Lake Champlain's Juniper Deep. Both drifts are positive features composed of highly laminated sediments. Drift B sits on a basement high while Drift A is built on a trough-filling acoustically-transparent sediment unit inferred to be a mass-transport event. These drifts are oriented approximately north–south and are parallel to a steep ridge along the eastern shore of the basin. Drift A, located at the bottom of a structural trough, is classified as a confined, elongate drift that transitions northward to become a system of upslope asymmetric mudwaves. Drift B is perched atop a structural high to the west of Drift A and is classified as a detached elongate drift. Bottom current depositional control was investigated using Acoustic Doppler Current Profilers (ADCPs) located across Drift A. Sediment cores were taken at the crest and at the edges of the Drift A and were dated. Drift source, deposition, and evolution show that these drifts are formed by a water column shear with the highest deposition occurring along its crest and western flank and began developing circa 8700–8800 year BP.

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

Friedman, A.; Barnard, J.J.; Briggs, R.J.

The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL), a collaborationof LBNL, LLNL, and PPPL, has achieved 60-fold pulse compression of ion beams on the Neutralized Drift Compression eXperiment (NDCX) at LBNL. In NDCX, a ramped voltage pulse from an induction cell imparts a velocity"tilt" to the beam; the beam's tail then catches up with its head in a plasma environment that provides neutralization. The HIFS-VNL's mission is to carry out studies of Warm Dense Matter (WDM) physics using ion beams as the energy source; an emerging thrust is basic target physics for heavy ion-driven Inertial Fusion Energy (IFE). Thesemore » goals require an improved platform, labeled NDCX-II. Development of NDCX-II at modest cost was recently enabled by the availability of induction cells and associated hardware from the decommissioned Advanced Test Accelerator (ATA) facility at LLNL. Our initial physics design concept accelerates a ~;;30 nC pulse of Li+ ions to ~;;3 MeV, then compresses it to ~;;1 ns while focusing it onto a mm-scale spot. It uses the ATA cells themselves (with waveforms shaped by passive circuits) to impart the final velocity tilt; smart pulsers provide small corrections. The ATA accelerated electrons; acceleration of non-relativistic ions involves more complex beam dynamics both transversely and longitudinally. We are using analysis, an interactive one-dimensional kinetic simulation model, and multidimensional Warp-code simulations to develop the NDCX-II accelerator section. Both LSP and Warp codes are being applied to the beam dynamics in the neutralized drift and final focus regions, and the plasma injection process. The status of this effort is described.« less

A comment on plasma 'pile-up' in the F-region

NASA Technical Reports Server (NTRS)

Rishbeth, H.; Hanson, W. B.

1974-01-01

At ionospheric heights, the geomagnetic field is virtually incompressible. In consequence, an electromagnetic drift can only compress the F-region plasma by moving it in a direction in which the field becomes stronger. This paper examines the rate of compression at mid-latitudes for three different assumptions about the ion motion.

Effects of Temporal Features and Order on the Apparent duration of a Visual Stimulus

PubMed Central

Bruno, Aurelio; Ayhan, Inci; Johnston, Alan

2012-01-01

The apparent duration of a visual stimulus has been shown to be influenced by its speed. For low speeds, apparent duration increases linearly with stimulus speed. This effect has been ascribed to the number of changes that occur within a visual interval. Accordingly, a higher number of changes should produce an increase in apparent duration. In order to test this prediction, we asked subjects to compare the relative duration of a 10-Hz drifting comparison stimulus with a standard stimulus that contained a different number of changes in different conditions. The standard could be static, drifting at 10 Hz, or mixed (a combination of variable duration static and drifting intervals). In this last condition the number of changes was intermediate between the static and the continuously drifting stimulus. For all standard durations, the mixed stimulus looked significantly compressed (∼20% reduction) relative to the drifting stimulus. However, no difference emerged between the static (that contained no changes) and the mixed stimuli (which contained an intermediate number of changes). We also observed that when the standard was displayed first, it appeared compressed relative to when it was displayed second with a magnitude that depended on standard duration. These results are at odds with a model of time perception that simply reflects the number of temporal features within an interval in determining the perceived passing of time. PMID:22461778

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

Friedman, A; Barnard, J J; Briggs, R J

The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL), a collaboration of LBNL, LLNL, and PPPL, has achieved 60-fold pulse compression of ion beams on the Neutralized Drift Compression eXperiment (NDCX) at LBNL. In NDCX, a ramped voltage pulse from an induction cell imparts a velocity 'tilt' to the beam; the beam's tail then catches up with its head in a plasma environment that provides neutralization. The HIFS-VNL's mission is to carry out studies of warm dense matter (WDM) physics using ion beams as the energy source; an emerging thrust is basic target physics for heavy ion-driven inertial fusion energymore » (IFE). These goals require an improved platform, labeled NDCX-II. Development of NDCX-II at modest cost was recently enabled by the availability of induction cells and associated hardware from the decommissioned advanced test accelerator (ATA) facility at LLNL. Our initial physics design concept accelerates an {approx} 30 nC pulse of Li{sup +} ions to {approx} 3 MeV, then compresses it to {approx} 1 ns while focusing it onto a mm-scale spot. It uses the ATA cells themselves (with waveforms shaped by passive circuits) to impart the final velocity tilt; smart pulsers provide small corrections. The ATA accelerated electrons; acceleration of non-relativistic ions involves more complex beam dynamics both transversely and longitudinally. We are using an interactive one-dimensional kinetic simulation model and multidimensional Warp-code simulations to develop the NDCX-II accelerator section. Both LSP and Warp codes are being applied to the beam dynamics in the neutralized drift and final focus regions, and the plasma injection process. The status of this effort is described.« less

Drifting solutions with elliptic symmetry for the compressible Navier-Stokes equations with density-dependent viscosity

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

An, Hongli, E-mail: kaixinguoan@163.com; Yuen, Manwai, E-mail: nevetsyuen@hotmail.com

2014-05-15

In this paper, we investigate the analytical solutions of the compressible Navier-Stokes equations with dependent-density viscosity. By using the characteristic method, we successfully obtain a class of drifting solutions with elliptic symmetry for the Navier-Stokes model wherein the velocity components are governed by a generalized Emden dynamical system. In particular, when the viscosity variables are taken the same as Yuen [M. W. Yuen, “Analytical solutions to the Navier-Stokes equations,” J. Math. Phys. 49, 113102 (2008)], our solutions constitute a generalization of that obtained by Yuen. Interestingly, numerical simulations show that the analytical solutions can be used to explain the driftingmore » phenomena of the propagation wave like Tsunamis in oceans.« less

Existence regimes for shocks in inhomogeneous magneto-plasmas having entropy

NASA Astrophysics Data System (ADS)

Iqbal, Javed; Yaqub Khan, M.

2018-04-01

The finding of connection of plasma density and temperature with entropy gives an incitement to study different plasma models with respect to entropy. Nonlinear dissipative one- and two-dimensional structures (shocks) are investigated in nonuniform magnetized plasma with respect to entropy. The dissipation comes in the medium through ion-neutral collisions. The linear dispersion relation is derived. The Korteweg-deVries-Burgers and Kadomtsev-Petviashvili-Burgers equations are derived for nonlinear drift waves in 1-D and 2-D by employing the drift approximation. It is found that vd/u ( vd is the diamagnetic drift velocity and u is the velocity of nonlinear structure) plays a significant role in the shock formation. It is also found that entropy has a significant effect on the strength of shocks. It is noticed that v d/u determines the rarefactive and compressive nature of the shocks. It is observed that upper and lower bounds exist for the shock velocity. It is also observed that the existing regimes for both one- and two-dimensional shocks for kappa distributed electrons are different from shocks with Cairns distributed electrons. Both rarefactive and compressive shocks are found for the 1-D drift waves with kappa distributed electrons. Interestingly, it is noticed that entropy enhances the strength of one- and two-dimensional shocks.

Effects of magnetic drift tangential to magnetic surfaces on neoclassical transport in non-axisymmetric plasmas

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

Matsuoka, Seikichi, E-mail: matsuoka@rist.or.jp; Satake, Shinsuke; Kanno, Ryutaro

2015-07-15

In evaluating neoclassical transport by radially local simulations, the magnetic drift tangential to a flux surface is usually ignored in order to keep the phase-space volume conservation. In this paper, effect of the tangential magnetic drift on the local neoclassical transport is investigated. To retain the effect of the tangential magnetic drift in the local treatment of neoclassical transport, a new local formulation for the drift kinetic simulation is developed. The compressibility of the phase-space volume caused by the tangential magnetic drift is regarded as a source term for the drift kinetic equation, which is solved by using a two-weightmore » δf Monte Carlo method for non-Hamiltonian system [G. Hu and J. A. Krommes, Phys. Plasmas 1, 863 (1994)]. It is demonstrated that the effect of the drift is negligible for the neoclassical transport in tokamaks. In non-axisymmetric systems, however, the tangential magnetic drift substantially changes the dependence of the neoclassical transport on the radial electric field E{sub r}. The peaked behavior of the neoclassical radial fluxes around E{sub r }={sub  }0 observed in conventional local neoclassical transport simulations is removed by taking the tangential magnetic drift into account.« less

Influence of a thin compressible insoluble liquid film on the eddy currents generated by interacting surface waves

NASA Astrophysics Data System (ADS)

Parfenyev, Vladimir M.; Vergeles, Sergey S.

2018-06-01

Recently the generation of eddy currents by interacting surface waves was observed experimentally. The phenomenon provides the possibility for manipulation of particles which are immersed in the fluid. The analysis shows that the amplitude of the established eddy currents produced by stationary surface waves does not depend on the fluid viscosity in the free surface case. The currents become parametrically larger, being inversely proportional to the square root of the fluid viscosity in the case when the fluid surface is covered by an almost incompressible thin liquid (i.e., shear elasticity is zero) film formed by an insoluble agent with negligible internal viscous losses as compared to the dissipation in the fluid bulk. Here we extend the theory for a thin insoluble film with zero shear elasticity and small shear and dilational viscosities on the case of an arbitrary elastic compression modulus. We find both contributions into the Lagrangian motion of passive tracers, which are the advection by the Eulerian vertical vorticity and the Stokes drift. Whereas the Stokes drift contribution preserves its value for the free surface case outside a thin viscous sublayer, the Eulerian vertical vorticity strongly depends on the fluid viscosity at high values of the film compression modulus. The Stokes drift acquires a strong dependence on the fluid viscosity inside the viscous sublayer; however, the change is compensated by an opposite change in the Eulerian vertical vorticity. As a result, the vertical dependence of the intensity of eddy currents is given by a sum of two decaying exponents with both decrements being of the order of the wave number. The decrements are numerically different, so the Eulerian contribution becomes dominant at some depth for the surface film with any compression modulus.

A robust H.264/AVC video watermarking scheme with drift compensation.

PubMed

Jiang, Xinghao; Sun, Tanfeng; Zhou, Yue; Wang, Wan; Shi, Yun-Qing

2014-01-01

A robust H.264/AVC video watermarking scheme for copyright protection with self-adaptive drift compensation is proposed. In our scheme, motion vector residuals of macroblocks with the smallest partition size are selected to hide copyright information in order to hold visual impact and distortion drift to a minimum. Drift compensation is also implemented to reduce the influence of watermark to the most extent. Besides, discrete cosine transform (DCT) with energy compact property is applied to the motion vector residual group, which can ensure robustness against intentional attacks. According to the experimental results, this scheme gains excellent imperceptibility and low bit-rate increase. Malicious attacks with different quantization parameters (QPs) or motion estimation algorithms can be resisted efficiently, with 80% accuracy on average after lossy compression.

A Robust H.264/AVC Video Watermarking Scheme with Drift Compensation

PubMed Central

Sun, Tanfeng; Zhou, Yue; Shi, Yun-Qing

2014-01-01

A robust H.264/AVC video watermarking scheme for copyright protection with self-adaptive drift compensation is proposed. In our scheme, motion vector residuals of macroblocks with the smallest partition size are selected to hide copyright information in order to hold visual impact and distortion drift to a minimum. Drift compensation is also implemented to reduce the influence of watermark to the most extent. Besides, discrete cosine transform (DCT) with energy compact property is applied to the motion vector residual group, which can ensure robustness against intentional attacks. According to the experimental results, this scheme gains excellent imperceptibility and low bit-rate increase. Malicious attacks with different quantization parameters (QPs) or motion estimation algorithms can be resisted efficiently, with 80% accuracy on average after lossy compression. PMID:24672376

Focusing Intense Charged Particle Beams with Achromatic Effects for Heavy Ion Fusion

NASA Astrophysics Data System (ADS)

Mitrani, James; Kaganovich, Igor

2012-10-01

Final focusing systems designed to minimize the effects of chromatic aberrations in the Neutralized Drift Compression Experiment (NDCX-II) are described. NDCX-II is a linear induction accelerator, designed to accelerate short bunches at high current. Previous experiments showed that neutralized drift compression significantly compresses the beam longitudinally (˜60x) in the z-direction, resulting in a narrow distribution in z-space, but a wide distribution in pz-space. Using simple lenses (e.g., solenoids, quadrupoles) to focus beam bunches with wide distributions in pz-space results in chromatic aberrations, leading to lower beam intensities (J/cm^2). Therefore, the final focusing system must be designed to compensate for chromatic aberrations. The paraxial ray equations and beam envelope equations are numerically solved for parameters appropriate to NDCX-II. Based on these results, conceptual designs for final focusing systems using a combination of solenoids and/or quadrupoles are optimized to compensate for chromatic aberrations. Lens aberrations and emittance growth will be investigated, and analytical results will be compared with results from numerical particle-in-cell (PIC) simulation codes.

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.

Evaluation of Flexible Force Sensors for Pressure Monitoring in Treatment of Chronic Venous Disorders.

PubMed

Parmar, Suresh; Khodasevych, Iryna; Troynikov, Olga

2017-08-21

The recent use of graduated compression therapy for treatment of chronic venous disorders such as leg ulcers and oedema has led to considerable research interest in flexible and low-cost force sensors. Properly applied low pressure during compression therapy can substantially improve the treatment of chronic venous disorders. However, achievement of the recommended low pressure levels and its accurate determination in real-life conditions is still a challenge. Several thin and flexible force sensors, which can also function as pressure sensors, are commercially available, but their real-life sensing performance has not been evaluated. Moreover, no researchers have reported information on sensor performance during static and dynamic loading within the realistic test conditions required for compression therapy. This research investigated the sensing performance of five low-cost commercial pressure sensors on a human-leg-like test apparatus and presents quantitative results on the accuracy and drift behaviour of these sensors in both static and dynamic conditions required for compression therapy. Extensive experimental work on this new human-leg-like test setup demonstrated its utility for evaluating the sensors. Results showed variation in static and dynamic sensing performance, including accuracy and drift characteristics. Only one commercially available pressure sensor was found to reliably deliver accuracy of 95% and above for all three test pressure points of 30, 50 and 70 mmHg.

Evaluation of Flexible Force Sensors for Pressure Monitoring in Treatment of Chronic Venous Disorders

PubMed Central

Parmar, Suresh; Khodasevych, Iryna; Troynikov, Olga

2017-01-01

The recent use of graduated compression therapy for treatment of chronic venous disorders such as leg ulcers and oedema has led to considerable research interest in flexible and low-cost force sensors. Properly applied low pressure during compression therapy can substantially improve the treatment of chronic venous disorders. However, achievement of the recommended low pressure levels and its accurate determination in real-life conditions is still a challenge. Several thin and flexible force sensors, which can also function as pressure sensors, are commercially available, but their real-life sensing performance has not been evaluated. Moreover, no researchers have reported information on sensor performance during static and dynamic loading within the realistic test conditions required for compression therapy. This research investigated the sensing performance of five low-cost commercial pressure sensors on a human-leg-like test apparatus and presents quantitative results on the accuracy and drift behaviour of these sensors in both static and dynamic conditions required for compression therapy. Extensive experimental work on this new human-leg-like test setup demonstrated its utility for evaluating the sensors. Results showed variation in static and dynamic sensing performance, including accuracy and drift characteristics. Only one commercially available pressure sensor was found to reliably deliver accuracy of 95% and above for all three test pressure points of 30, 50 and 70 mmHg. PMID:28825672

Mesozoic Deformation and Its Geological Significance in the Southern Margin of the South China Sea

NASA Astrophysics Data System (ADS)

Zhu, Rongwei; Liu, Hailing; Yao, Yongjian; Wang, Yin

2018-05-01

The pre-Eocene history of the region around the present South China Sea is not well known. New multi-channel seismic profiles provide valuable insights into the probable Mesozoic history of this region. Detailed structural and stratigraphic interpretations of the multi-channel seismic profiles, calibrated with relevant drilling and dredging data, show major Mesozoic structural features. A structural restoration was done to remove the Cenozoic tectonic influence and calculate the Mesozoic tectonic compression ratios. The results indicate that two groups of compressive stress with diametrically opposite orientations, S(S)E-N(N)W and N(N)W-S(S)E, were active during the Mesozoic. The compression ratio values gradually decrease from north to south and from west to east in each stress orientation. The phenomena may be related to the opening of the proto-South China Sea (then located in south of the Nansha block) and the rate at which the Nansha block drifted northward in the late Jurassic to late Cretaceous. The Nansha block drifted northward until it collided and sutured with the southern China margin. The opening of the present South China Sea may be related to this suture zone, which was a tectonic zone of weakness.

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

Leitner, M.; Bieniosek, F.; Kwan, J.

The Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL), a collaboration between Lawrence Berkeley National Laboratory (LBNL), Lawrence Livermore National Laboratory (LLNL), and Princeton Plasma Physics Laboratory (PPPL), is currently constructing a new induction linear accelerator, called Neutralized Drift Compression eXperiment NDCX-II. The accelerator design makes effective use of existing components from LLNL's decommissioned Advanced Test Accelerator (ATA), especially induction cells and Blumlein voltage sources that have been transferred to LBNL. We have developed an aggressive acceleration 'schedule' that compresses the emitted ion pulse from 500 ns to 1 ns in just 15 meters. In the nominal design concept, 30more » nC of Li{sup +} are accelerated to 3.5 MeV and allowed to drift-compress to a peak current of about 30 A. That beam will be utilized for warm dense matter experiments investigating the interaction of ion beams with matter at high temperature and pressure. Construction of the accelerator will be complete within a period of approximately two and a half years and will provide a worldwide unique opportunity for ion-driven warm dense matter experiments as well as research related to novel beam manipulations for heavy ion fusion drivers.« less

Solving the jitter problem in microwave compressed ultrafast electron diffraction instruments: Robust sub-50 fs cavity-laser phase stabilization

PubMed Central

Otto, M. R.; René de Cotret, L. P.; Stern, M. J.; Siwick, B. J.

2017-01-01

We demonstrate the compression of electron pulses in a high-brightness ultrafast electron diffraction instrument using phase-locked microwave signals directly generated from a mode-locked femtosecond oscillator. Additionally, a continuous-wave phase stabilization system that accurately corrects for phase fluctuations arising in the compression cavity from both power amplification and thermal drift induced detuning was designed and implemented. An improvement in the microwave timing stability from 100 fs to 5 fs RMS is measured electronically, and the long-term arrival time stability (>10 h) of the electron pulses improves to below our measurement resolution of 50 fs. These results demonstrate sub-relativistic ultrafast electron diffraction with compressed pulses that is no longer limited by laser-microwave synchronization. PMID:28852686

Drifting Diaphyses: Asymmetry in Diametric Growth and Adaptation Along the Humeral and Femoral Length.

PubMed

Maggiano, Isabel S; Maggiano, Corey M; Tiesler, Vera G; Chi-Keb, Julio R; Stout, Sam D

2015-10-01

This study quantifies regional histomorphological variation along the human humeral and femoral diaphysis in order to gain information on diaphyseal growth and modeling drift patterns. Three thin sections at 40, 50, and 60% bone length were prepared from a modern Mexican skeletal sample with known age and sex to give a longitudinal perspective on the drifting cortex (12 adults and juveniles total, 7 male and 5 female). Point-count techniques were applied across eight cross-sectional regions of interest using the starburst sampling pattern to quantify percent periosteal and endosteal primary lamellar bone at each diaphyseal level. The results of this study show a posterio-medial drift pattern in the humerus with a posterior rotational trend along the diaphysis. In the femur, we observed a consistent lateral to anteriolateral drift and an increase in primary lamellar bone area of both, periosteal and endosteal origin, towards the distal part of the diaphysis. These observations characterize drifting diaphyses in greater detail, raising important questions about how to resolve microscopic and macroscopic cross-sectional analysis towards a more complete understanding of bone growth and mechanical adaptation. Accounting for modeling drift has the potential to positively impact age and physical activity estimation, and explain some of the significant regional variation in bone histomorphology seen within (and between) bone cross-sections due to differing ages of tissue formation. More study is necessary, however, to discern between possible drift scenarios and characterize populational variation. © 2015 Wiley Periodicals, Inc.

Theoretical analysis and simulation study of the deep overcompression mode of velocity bunching for a comblike electron bunch train

NASA Astrophysics Data System (ADS)

Wang, Dan; Yan, Lixin; Du, YingChao; Huang, Wenhui; Gai, Wei; Tang, Chuanxiang

2018-02-01

Premodulated comblike electron bunch trains are used in a wide range of research fields, such as for wakefield-based particle acceleration and tunable radiation sources. We propose an optimized compression scheme for bunch trains in which a traveling wave accelerator tube and a downstream drift segment are together used as a compressor. When the phase injected into the accelerator tube for the bunch train is set to ≪-10 0 ° , velocity bunching occurs in a deep overcompression mode, which reverses the phase space and maintains a velocity difference within the injected beam, thereby giving rise to a compressed comblike electron bunch train after a few-meter-long drift segment; we call this the deep overcompression scheme. The main benefits of this scheme are the relatively large phase acceptance and the uniformity of compression for the bunch train. The comblike bunch train generated via this scheme is widely tunable: For the two-bunch case, the energy and time spacings can be continuously adjusted from +1 to -1 MeV and from 13 to 3 ps, respectively, by varying the injected phase of the bunch train from -22 0 ° to -14 0 ° . Both theoretical analysis and beam dynamics simulations are presented to study the properties of the deep overcompression scheme.

Mesozoic Compressional Folds of the Nansha Waters, Southern South China Sea

NASA Astrophysics Data System (ADS)

Zhu, R.; Liu, H.; Yao, Y.; Wang, Y.

2017-12-01

As an important part of the South China Sea, the southern margin of the South China Sea is fundamental to understand the interaction of the Eurasian, Pacific and Indian-Australian plates and the evolution of the South China Sea. Some multi-channel seismic profiles of the Nansha waters together with published drillings and dredge data were correlated for interpretation. The strata of the study region can be divided into the upper, middle and lower structural layers. The upper and middle structural layers with extensional tectonics are Cenozoic; the lower structural layer suffered compression is Mesozoic. Further structural restoration was done to remove the Cenozoic tectonic influence and to calculate the Mesozoic tectonic compression ratios. The results indicate that two diametrically opposite orientations of compressive stress, S(S)E towards N(N)W orientation and N(N)W towards S(S)E orientation respectively, once existed in the lower structural layer of the study area and shared the same variation trend. The compression ratio values gradually decrease both from the north to the south and from the west to the east in each stress orientation. The phenomena may be related to the opening of the proto-South China Sea (then located in south of the Nansha block) and the rate of the Nansha block drifted northward in Late Jurassic to Late Cretaceous, which had pushed the Nansha block drifted northward until it collided and sutured with the Southern China Margin. Thus the opening of the present-day South China Sea may be related to this suture zone, which was tectonically weakness zone.Key words: Mesozoic compression; structural restoration; proto-South China Sea; Nansha waters; Southern South China Sea; Acknowledgements: The work was granted by the National Natural Science Foundation of China (Grant Nos. 41476039, 91328205, 41576068 and 41606080).

PRN 90-3: Announcing the Formation of an Industry-Wide Spray Drift Task Force

EPA Pesticide Factsheets

A Spray Drift Task Force has been organized pursuant to provisions of FIFRA section 3 (c)(2)(B)(ii) to share the cost of developing a generic spray drift data base capable of satisfying spray drift data requirements for pesticide product registrations.

An effective simplified model of composite compression struts for partially-restrained steel frame with reinforced concrete infill walls

NASA Astrophysics Data System (ADS)

Sun, Guohua; Chuang-Sheng, Walter Yang; Gu, Qiang; DesRoches, Reginald

2018-04-01

To resolve the issue regarding inaccurate prediction of the hysteretic behavior by micro-based numerical analysis for partially-restrained (PR) steel frames with solid reinforced concrete (RC) infill walls, an innovative simplified model of composite compression struts is proposed on the basis of experimental observation on the cracking distribution, load transferring mechanism, and failure modes of RC infill walls filled in PR steel frame. The proposed composite compression struts model for the solid RC infill walls is composed of α inclined struts and main diagonal struts. The α inclined struts are used to reflect the part of the lateral force resisted by shear connectors along the frame-wall interface, while the main diagonal struts are introduced to take into account the rest of the lateral force transferred along the diagonal direction due to the complicated interaction between the steel frame and RC infill walls. This study derives appropriate formulas for the effective widths of the α inclined strut and main diagonal strut, respectively. An example of PR steel frame with RC infill walls simulating simulated by the composite inclined compression struts model is illustrated. The maximum lateral strength and the hysteresis curve shape obtained from the proposed composite strut model are in good agreement with those from the test results, and the backbone curve of a PR steel frame with RC infill walls can be predicted precisely when the inter-story drift is within 1%. This simplified model can also predict the structural stiffness and the equivalent viscous damping ratio well when the inter-story drift ratio exceeds 0.5%.

Drift-free MPEG-4 AVC semi-fragile watermarking

NASA Astrophysics Data System (ADS)

Hasnaoui, M.; Mitrea, M.

2014-02-01

While intra frame drifting is a concern for all types of MPEG-4 AVC compressed-domain video processing applications, it has a particular negative impact in watermarking. In order to avoid the drift drawbacks, two classes of solutions are currently considered in the literature. They try either to compensate the drift distortions at the expense of complex decoding/estimation algorithms or to restrict the insertion to the blocks which are not involved in the prediction, thus reducing the data payload. The present study follows a different approach. First, it algebraically models the drift distortion spread problem by considering the analytic expressions of the MPEG-4 AVC encoding operations. Secondly, it solves the underlying algebraic system under drift-free constraints. Finally, the advanced solution is adapted to take into account the watermarking peculiarities. The experiments consider an m-QIM semi-fragile watermarking method and a video surveillance corpus of 80 minutes. For prescribed data payload (100 bit/s), robustness (BER < 0.1 against transcoding at 50% in stream size), fragility (frame modification detection with accuracies of 1/81 from the frame size and 3s) and complexity constraints, the modified insertion results in gains in transparency of 2 dB in PSNR, of 0.4 in AAD, of 0.002 in IF, of 0.03 in SC, of 0.017 NCC and 22 in DVQ.

Soil-like deposits observed by Sojourner, the Pathfinder rover

USGS Publications Warehouse

Moore, Henry J.; Bickler, Donald B.; Crisp, Joy A.; Eisen, Howard J.; Gensler, Jeffrey A.; Haldemann, Albert F.C.; Matijevic, Jacob R.; Reid, Lisa K.; Pavlics, Ferenc

1999-01-01

Most of the soil-like materials at the Pathfinder landing site behave like moderately dense soils on Earth with friction angles near 34°-39° and are called cloddy deposits. Cloddy deposits appear to be poorly sorted with dust-sized to granule-sized mineral or rock grains; they may contain pebbles, small rock fragments, and clods. Thin deposits of porous, compressible drifts with friction angles near 26°-28° are also present. Drifts are fine grained. Cohesions of both types of deposits are small. There may be indurated soil-like deposits and/or coated or crusted rocks. Cloddy deposits may be fluvial sediments of the Ares-Tiu floods, but other origins, such as ejecta from nearby impact craters, should be considered. Drifts are probably dusts that settled from the Martian atmosphere. Remote-sensing signatures of the deposits inferred from rover observations are consistent with those observed from orbit and Earth.

A Web 2.0 Interface to Ion Stopping Power and Other Physics Routines for High Energy Density Physics Applications

NASA Astrophysics Data System (ADS)

Stoltz, Peter; Veitzer, Seth

2008-04-01

We present a new Web 2.0-based interface to physics routines for High Energy Density Physics applications. These routines include models for ion stopping power, sputtering, secondary electron yields and energies, impact ionization cross sections, and atomic radiated power. The Web 2.0 interface allows users to easily explore the results of the models before using the routines within other codes or to analyze experimental results. We discuss how we used various Web 2.0 tools, including the Python 2.5, Django, and the Yahoo User Interface library. Finally, we demonstrate the interface by showing as an example the stopping power algorithms researchers are currently using within the Hydra code to analyze warm, dense matter experiments underway at the Neutralized Drift Compression Experiment facility at Lawrence Berkeley National Laboratory.

Seasonal variation in drifting eggs and larvae in the upper Yangtze, China.

PubMed

Jiang, Wei; Liu, Huan-Zhang; Duan, Zhong-Hua; Cao, Wen-Xuan

2010-05-01

From 5 March to 25 July 2008, ichthyoplankton drifting into the Three Gorges Reservoir from the upper reaches of the Yangtze River were sampled daily to investigate the species composition, abundance, and seasonal variation in early-stage fishes in this area. Twenty-eight species belonging to five orders and 17 families or subfamilies were identified by analyzing fish eggs and larvae, and a total of 14.16 billion individuals were estimated drifting through the sampling section during the investigation. Among the ichthyoplankton sampled, species in Cultrinae, Cobitidae, Gobioninae and Gobiidae, along with the common carp (Cyprinus carpio Linnaeus), comprised 89.6% of the total amount. Six peaks of drift density were identified during the sampling period, and a significant correlation was found between drift density with water discharge. The dominant species were different in each drift peak, indicating different spawning times for the major species. The total amount of the four major Chinese carps that drifted through the sampling section was estimated as 0.88 billion, indicating an increase in the population sizes of these species in the upper reaches of the Yangtze River after construction of the Three Gorges Dam. Actually, these reaches have become the largest spawning area for the four major Chinese carps in the Yangtze River. The large total amount of eggs and larvae drifting through this section demonstrated that the upper reaches of the Yangtze River provided important spawning sites for many fish species, and that conservation of this area should be of great concern.

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

Friedman, A; Kwan, J

Earlier this year, the U.S. Department of Energy Office of Fusion Energy Sciences approved the NDCX-II project, a second-generation Neutralized Drift Compression eXperiment. NDCX-II is a collaborative effort of scientists and engineers from Lawrence Berkeley National Laboratory (LBNL), Lawrence Livermore National Laboratory (LLNL), and the Princeton Plasma Physics Laboratory (PPPL), in a formal collaboration known as the Virtual National Laboratory for Heavy Ion Fusion Science (HIFS-VNL). Supported by $11 M of funding from the American Recovery and Reinvestment Act, construction at LBNL commenced in July of 2009, with completion anticipated in March of 2012. Applications of this facility will includemore » studies of: the basic physics of the poorly understood 'warm dense matter' regime of temperatures around 1 eV and densities near solid, using uniform, volumetric ion heating of thin foil targets; ion energy coupling into an ablating plasma (such as that which occurs in an inertial fusion target) using beams with time-varying kinetic energy; space-charge-dominated ion beam dynamics; and beam focusing and pulse compression in neutralizing plasma. The machine will complement facilities at GSI in Darmstadt, Germany, but will employ lower ion kinetic energies and commensurately shorter stopping ranges in matter. Much of this research will contribute directly toward the collaboration's ultimate goal of electric power production via heavy-ion beam-driven inertial confinement fusion ('Heavy-Ion Fusion', or HIF). In inertial fusion, a target containing fusion fuel is heated by energetic 'driver' beams, and undergoes a miniature thermonuclear explosion. Currently the largest U.S. research program in inertial confinement is at Livermore's National Ignition Facility (NIF), a multibillion-dollar, stadium-sized laser facility optimized for studying physics issues relevant to nuclear stockpile stewardship. Nonetheless, NIF is expected to establish the fundamental feasibility of fusion ignition on the laboratory scale, and thus advance this approach to fusion energy. Heavy ion accelerators have a number of attributes (such as efficiency, longevity, and use of magnetic fields for final focusing) that make them attractive candidates as Inertial Fusion energy (IFE) drivers As with LBNL's existing NDCX-I, the new machine will produce short ion pulses using the technique of neutralized drift compression. A head-to-tail velocity gradient is imparted to the beam, which then shortens as it drifts in neutralizing plasma that suppresses space-charge forces. NDCX-II will make extensive use of induction cells and other hardware from the decommissioned ATA facility at LLNL. Figure (1) shows the layout of the facility, to be sited in LBNL's Building 58 alongside the existing NDCX-I apparatus. This second-generation facility represents a significant upgrade from the existing NDCX-I. It will be extensible and reconfigurable; in the configuration that has received the most emphasis, each NDCX-II pulse will deliver 30 nC of ions at 3 MeV into a mm-scale spot onto a thin-foil target. Pulse compression to {approx} 1 ns occurs in the accelerator as well as in the drift compression line; the beam is manipulated using suitably tailored voltage waveforms in the accelerating gaps. NDCX-II employs novel beam dynamics. To use the 200 kV Blumlein power supplies from ATA (blue cylinders in the figure), the pulse duration must first be reduced to less than 70 ns. This shortening is accomplished in an initial stage of non-neutral drift compression, downstream of the injector and the first few induction cells. The compression is sufficiently rapid that fewer than ten long-pulse waveform generators are needed, with Blumleins powering the rest of the acceleration. Extensive simulation studies have enabled an attractive physics design; these employ both a new 1-D code (ASP) and the VNL's workhorse 2-D/3-D code Warp. Snapshots from a simulation movie (available online) appear in Fig. 2. Studies on a dedicated test stand are quantifying the performance of the ATA hardware and of pulsed solenoids that will provide transverse beam confinement (ions require much stronger fields than the electrons accelerated by ATA). For more information, see the recent article in the Berkeley Lab News and references therein. Joe Kwan is the NDCX-II project manager and Alex Friedman is the leader for the physics design.« less

Drift tube suspension for high intensity linear accelerators

DOEpatents

Liska, D.J.; Schamaun, R.G.; Clark, D.C.; Potter, R.C.; Frank, J.A.

1980-03-11

The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

Profiling of the injected charge drift current transients by cross-sectional scanning technique

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

Gaubas, E., E-mail: eugenijus.gaubas@ff.vu.lt; Ceponis, T.; Pavlov, J.

2014-02-07

The electric field distribution and charge drift currents in Si particle detectors are analyzed. Profiling of the injected charge drift current transients has been implemented by varying charge injection position within a cross-sectional boundary of the particle detector. The obtained profiles of the induction current density and duration of the injected charge drift pulses fit well the simulated current variations. Induction current transients have been interpreted by different stages of the bipolar and monopolar drift of the injected carriers. Profiles of the injected charge current transients registered in the non-irradiated and neutron irradiated Si diodes are compared. It has beenmore » shown that the mixed regime of the competing processes of drift, recombination, and diffusion appears in the measured current profiles on the irradiated samples. The impact of the avalanche effects can be ignored based on the investigations presented. It has been shown that even a simplified dynamic model enabled us to reproduce the main features of the profiled transients of induced charge drift current.« less

Artifacts in slab average-intensity-projection images reformatted from JPEG 2000 compressed thin-section abdominal CT data sets.

PubMed

Kim, Bohyoung; Lee, Kyoung Ho; Kim, Kil Joong; Mantiuk, Rafal; Kim, Hye-ri; Kim, Young Hoon

2008-06-01

The objective of our study was to assess the effects of compressing source thin-section abdominal CT images on final transverse average-intensity-projection (AIP) images. At reversible, 4:1, 6:1, 8:1, 10:1, and 15:1 Joint Photographic Experts Group (JPEG) 2000 compressions, we compared the artifacts in 20 matching compressed thin sections (0.67 mm), compressed thick sections (5 mm), and AIP images (5 mm) reformatted from the compressed thin sections. The artifacts were quantitatively measured with peak signal-to-noise ratio (PSNR) and a perceptual quality metric (High Dynamic Range Visual Difference Predictor [HDR-VDP]). By comparing the compressed and original images, three radiologists independently graded the artifacts as 0 (none, indistinguishable), 1 (barely perceptible), 2 (subtle), or 3 (significant). Friedman tests and exact tests for paired proportions were used. At irreversible compressions, the artifacts tended to increase in the order of AIP, thick-section, and thin-section images in terms of PSNR (p < 0.0001), HDR-VDP (p < 0.0001), and the readers' grading (p < 0.01 at 6:1 or higher compressions). At 6:1 and 8:1, distinguishable pairs (grades 1-3) tended to increase in the order of AIP, thick-section, and thin-section images. Visually lossless threshold for the compression varied between images but decreased in the order of AIP, thick-section, and thin-section images (p < 0.0001). Compression artifacts in thin sections are significantly attenuated in AIP images. On the premise that thin sections are typically reviewed using an AIP technique, it is justifiable to compress them to a compression level currently accepted for thick sections.

Proportional drift tubes for large area muon detectors

NASA Technical Reports Server (NTRS)

Cho, C.; Higashi, S.; Hiraoka, N.; Maruyama, A.; Okusawa, T.; Sato, T.; Suwada, T.; Takahashi, T.; Umeda, H.

1985-01-01

A proportional drift chamber which consists of eight rectangular drift tubes with cross section of 10 cm x 5 cm, a sense wire of 100 micron phi gold-plated tungsten wire and the length of 6 m, was tested using cosmic ray muons. Spatial resolution (rms) is between 0.5 and 1 mm over drift space of 50 mm, depending on incident angle and distance from sense wire.

[Further study on possibility of diffusion of Oncomelania hupensis with water in river channels of the east route of South-to-North Water Diversion Project].

PubMed

Huang, Yi-Xin; Hang, De-Rong; Tang, Hong-Ping; Sun, Dao-Kuan; Zhou, Can-Hua; Gao, Jin-Bin; Zheng, Bo; Hu, Gui-Quan; Li, Qian; Huang, Yong-Jun; She, Guang-Song; Ren, Zhi-Yuan

2014-12-01

To study the drifting law of floats and potential risks of Oncomelania hupensis diffusion in the water diversion rivers of the east route of South-to-North Water Diversion Project. The O. hupensis snails in the river channels were monitored by the salvage method and snail luring method with rice straw curtains, and the diffusion possibility of snails along with water was assessed through the drift test of floats with GPS. In the flood seasons from 2006 to 2013, totally 8 338.0 kg of floats were salvaged, and 2 100 rice straw curtains were put into water in the Li Canal and Jinbao shipping channel, but no Oncomelania snails were found. The drift test of floats with GPS before water diversion showed that the flow velocity on water surface (northbound) was 0.45 m/s, the average drift velocity of the floats was 0.56 - 0.60 m/s, and the average drift distances each time were 999.70 - 1 995.50 m in the Gaoshui River section, while there were no obvious drift in Jinbao shipping channel section. During the water diversion period, the flow velocity on water surface (northbound) was 0.45 m/s, the average drift velocity of the floats was 0.35 - 0.41m/s, and the average drift distances each time were 1 248.06 -1 289.44 m in the Gaoshui River, while in Jinbao shipping channel section, the flow velocity on water surface was 0.28 m/s, the average drift velocity of the floats was 0.25 - 0.27 m/s, and the average drift distances each time were 477.76 - 496.38 m. The drift test showed that the floats gradually closed to the river bank as affected by water flow, wind direction and ship waves, when blocked by the reeds, water plants or other obstacles, and they would stopped and could not continue to drift without outside help. There are no Oncomelania snails found in the river channels of the east route of South-to-North Water Diversion Project. The drifting distance of the floating debris along with the water is restricted by the flow rate and shore environment.

Resolving Structural Isomers of Monosaccharide Methyl Glycosides Using Drift Tube and Traveling Wave Ion Mobility Mass Spectrometry

PubMed Central

Li, Hongli; Giles, Kevin; Bendiak, Brad; Kaplan, Kimberly; Siems, William F.; Hill, Herbert H.

2013-01-01

Monosaccharide structural isomers including sixteen methyl-D-glycopyranosides and four methyl-N-acetylhexosamines were subjected to ion mobility measurements by electrospray ion mobility mass spectrometry. Two ion mobility-MS systems were employed: atmospheric pressure drift tube ion mobility time-of-flight mass spectrometry and a Synapt G2 HDMS system which incorporates a low pressure traveling wave ion mobility separator. All the compounds were investigated as [M+Na]+ ions in the positive mode. A majority of the monosaccharide structural isomers exhibited different mobility drift times in either system, depending on differences in their anomeric and stereochemical configurations. In general, drift time patterns (relative drift times of isomers) matched between the two instruments. Higher resolving power was observed using the atmospheric pressure drift tube. Collision cross section values of monosaccharide structural isomers were directly calculated from the atmospheric pressure ion mobility experiments and a collision cross section calibration curve was made for the traveling wave ion mobility instrument. Overall, it was demonstrated that ion mobility-mass spectrometry using either drift tube or traveling wave ion mobility is a valuable technique for resolving subtle variations in stereochemistry among the sodium adducts of monosaccharide methyl glycosides. PMID:22339760

Energetic Particles Dynamics in Mercury's Magnetosphere

NASA Technical Reports Server (NTRS)

Walsh, Brian M.; Ryou, A.S.; Sibeck, D. G.; Alexeev, I. I.

2013-01-01

We investigate the drift paths of energetic particles in Mercury's magnetosphere by tracing their motion through a model magnetic field. Test particle simulations solving the full Lorentz force show a quasi-trapped energetic particle population that gradient and curvature drift around the planet via "Shabansky" orbits, passing though high latitudes in the compressed dayside by equatorial latitudes on the nightside. Due to their large gyroradii, energetic H+ and Na+ ions will typically collide with the planet or the magnetopause and will not be able to complete a full drift orbit. These simulations provide direct comparison for recent spacecraft measurements from MESSENGER. Mercury's offset dipole results in an asymmetric loss cone and therefore an asymmetry in particle precipitation with more particles precipitating in the southern hemisphere. Since the planet lacks an atmosphere, precipitating particles will collide directly with the surface of the planet. The incident charged particles can kick up neutrals from the surface and have implications for the formation of the exosphere and weathering of the surface

Compressive and rarefactive double layers in non-uniform plasma with q-nonextensive distributed electrons

NASA Astrophysics Data System (ADS)

Shan, S. Ali; Saleem, H.

2018-05-01

Electrostatic solitary waves and double layers (DLs) formed by the coupled ion acoustic (IA) and drift waves have been investigated in non-uniform plasma using q-nonextensive distribution function for the electrons and assuming ions to be cold Ti< Te. It is found that both compressive and rarefactive nonlinear structures (solitary waves and DLs) are possible in such a system. The steeper gradients are supportive for compressive solitary (and double layers) and destructive for rarefactive ones. The q-nonextensivity parameter q and the magnitudes of gradient scale lengths of density and temperature have significant effects on the amplitude of the double layers (and double layers) as well as on the speed of these structures. This theoretical model is general which has been applied here to the F-region ionosphere for illustration.

Gas and water flow in an excavation-induced fracture network around an underground drift: A case study for a radioactive waste repository in clay rock

NASA Astrophysics Data System (ADS)

de La Vaissière, Rémi; Armand, Gilles; Talandier, Jean

2015-02-01

The Excavation Damaged Zone (EDZ) surrounding a drift, and in particular its evolution, is being studied for the performance assessment of a radioactive waste underground repository. A specific experiment (called CDZ) was designed and implemented in the Meuse/Haute-Marne Underground Research Laboratory (URL) in France to investigate the EDZ. This experiment is dedicated to study the evolution of the EDZ hydrogeological properties (conductivity and specific storage) of the Callovo-Oxfordian claystone under mechanical compression and artificial hydration. Firstly, a loading cycle applied on a drift wall was performed to simulate the compression effect from bentonite swelling in a repository drift (bentonite is a clay material to be used to seal drifts and shafts for repository closure purpose). Gas tests (permeability tests with nitrogen and tracer tests with helium) were conducted during the first phase of the experiment. The results showed that the fracture network within the EDZ was initially interconnected and opened for gas flow (particularly along the drift) and then progressively closed with the increasing mechanical stress applied on the drift wall. Moreover, the evolution of the EDZ after unloading indicated a self-sealing process. Secondly, the remaining fracture network was resaturated to demonstrate the ability to self-seal of the COx claystone without mechanical loading by conducting from 11 to 15 repetitive hydraulic tests with monitoring of the hydraulic parameters. During this hydration process, the EDZ effective transmissivity dropped due to the swelling of the clay materials near the fracture network. The hydraulic conductivity evolution was relatively fast during the first few days. Low conductivities ranging at 10-10 m/s were observed after four months. Conversely, the specific storage showed an erratic evolution during the first phase of hydration (up to 60 days). Some uncertainty remains on this parameter due to volumetric strain during the sealing of the fractures. The hydration was stopped after one year and cross-hole hydraulic tests were performed to determine more accurately the specific storage as well as the hydraulic conductivity at a meter-scale. All hydraulic conductivity values measured at the injection interval and at the observation intervals were all below 10-10 m/s. Moreover, the preferential inter-connectivity along the drift disappeared. Specific storage values at the observation and injection intervals were similar. Furthermore they were in agreement with the value obtained at the injection interval within the second hydration phase (60 days after starting hydration). The graphical abstract synthesizes the evolution of the hydraulic/gas conductivity for 8 intervals since the beginning of the CDZ experiment. The conductivity limit of 10-10 m/s corresponds to the lower bound hydraulic definition of the EDZ and it is demonstrated that EDZ can be sealed. This is a significant result in the demonstration of the long-term safety of a repository.

An unstaggered central scheme on nonuniform grids for the simulation of a compressible two-phase flow model

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

Touma, Rony; Zeidan, Dia

In this paper we extend a central finite volume method on nonuniform grids to the case of drift-flux two-phase flow problems. The numerical base scheme is an unstaggered, non oscillatory, second-order accurate finite volume scheme that evolves a piecewise linear numerical solution on a single grid and uses dual cells intermediately while updating the numerical solution to avoid the resolution of the Riemann problems arising at the cell interfaces. We then apply the numerical scheme and solve a classical drift-flux problem. The obtained results are in good agreement with corresponding ones appearing in the recent literature, thus confirming the potentialmore » of the proposed scheme.« less

Gas turbine engine adapted for use in combination with an apparatus for separating a portion of oxygen from compressed air

DOEpatents

Bland, Robert J [Oviedo, FL; Horazak, Dennis A [Orlando, FL

2012-03-06

A gas turbine engine is provided comprising an outer shell, a compressor assembly, at least one combustor assembly, a turbine assembly and duct structure. The outer shell includes a compressor section, a combustor section, an intermediate section and a turbine section. The intermediate section includes at least one first opening and at least one second opening. The compressor assembly is located in the compressor section to define with the compressor section a compressor apparatus to compress air. The at least one combustor assembly is coupled to the combustor section to define with the combustor section a combustor apparatus. The turbine assembly is located in the turbine section to define with the turbine section a turbine apparatus. The duct structure is coupled to the intermediate section to receive at least a portion of the compressed air from the compressor apparatus through the at least one first opening in the intermediate section, pass the compressed air to an apparatus for separating a portion of oxygen from the compressed air to produced vitiated compressed air and return the vitiated compressed air to the intermediate section via the at least one second opening in the intermediate section.

Soliton compression to few-cycle pulses with a high quality factor by engineering cascaded quadratic nonlinearities.

PubMed

Zeng, Xianglong; Guo, Hairun; Zhou, Binbin; Bache, Morten

2012-11-19

We propose an efficient approach to improve few-cycle soliton compression with cascaded quadratic nonlinearities by using an engineered multi-section structure of the nonlinear crystal. By exploiting engineering of the cascaded quadratic nonlinearities, in each section soliton compression with a low effective order is realized, and high-quality few-cycle pulses with large compression factors are feasible. Each subsequent section is designed so that the compressed pulse exiting the previous section experiences an overall effective self-defocusing cubic nonlinearity corresponding to a modest soliton order, which is kept larger than unity to ensure further compression. This is done by increasing the cascaded quadratic nonlinearity in the new section with an engineered reduced residual phase mismatch. The low soliton orders in each section ensure excellent pulse quality and high efficiency. Numerical results show that compressed pulses with less than three-cycle duration can be achieved even when the compression factor is very large, and in contrast to standard soliton compression, these compressed pulses have minimal pedestal and high quality factor.

IMS - MS Data Extractor

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

2015-10-20

An automated drift time extraction and computed associated collision cross section software tool for small molecule analysis with ion mobility spectrometry-mass spectrometry (IMS-MS). The software automatically extracts drift times and computes associated collision cross sections for small molecules analyzed using ion mobility spectrometry-mass spectrometry (IMS-MS) based on a target list of expected ions provided by the user.

Canonical angular momentum compression near the Brillouin limit

NASA Astrophysics Data System (ADS)

Jeong, E.; Gilson, E.; Fajans, J.

2000-10-01

Near the Brillouin limit, the angular momentum of a trapped, T=0, pure-electron plasma approaches zero. If the plasma expands axially, its density would appear to drop. However, the plasma's canonical angular momentum is not changed by an axial expansion, so the plasma must stay near the Brillouin limit; thus the plasma's density cannot change when it is expanded. The only way for the plasma density to remain constant as the plasma length increases is for the plasma radius to decrease. Dynamically, this decrease is caused by the polarization drift induced by a small decrease in the density. In this poster we present preliminary experimental evidence demonstrating this radial compression. This work was supported by the ONR.

Structural Characterization of Unsaturated Phosphatidylcholines Using Traveling Wave Ion Mobility Spectrometry

PubMed Central

Kim, Hugh I.; Kim, Hyungjun; Pang, Eric S.; Ryu, Ernest K.; Beegle, Luther W.; Loo, Joseph A.; Goddard, William A.; Kanik, Isik

2009-01-01

A number of phosphatidylcholine (PC) cations spanning a mass range of 400 to 1000 Da are investigated using electrospray ionization mass spectrometry coupled with traveling wave ion mobility spectrometry (TWIMS). A high correlation between mass and mobility is demonstrated with saturated phosphatidylcholine cations in N2. A significant deviation from this mass-mobility correlation line is observed for the unsaturated PC cation. We found that the double bond in the acyl chain causes a 5% reduction in drift time. The drift time is reduced at a rate of ~1% for each additional double bond. Theoretical collision cross sections of PC cations exhibit good agreement with experimentally evaluated values. Collision cross sections are determined using the recently derived relationship between mobility and drift time in TWIMS stacked ring ion guide (SRIG) and compared to estimate collision cross-sections using empiric calibration method. Computational analysis was performed using the modified trajectory (TJ) method with nonspherical N2 molecules as the drift gas. The difference between estimated collision cross-sections and theoretical collision cross-sections of PC cations is related to the sensitivity of the PC cation collision cross-sections to the details of the ion-neutral interactions. The origin of the observed correlation and deviation between mass and mobility of PC cations is discussed in terms of the structural rigidity of these molecules using molecular dynamic simulations. PMID:19764704

Investigation of drift gas selectivity in high resolution ion mobility spectrometry with mass spectrometry detection.

PubMed

Matz, Laura M; Hill, Herbert H; Beegle, Luther W; Kanik, Isik

2002-04-01

Recent studies in electrospray ionization (ESI)/ion mobility spectrometry (IMS) have focussed on employing different drift gases to alter separation efficiency for some molecules. This study investigates four structurally similar classes of molecules (cocaine and metabolites, amphetamines, benzodiazepines, and small peptides) to determine the effect of structure on relative mobility changes in four drift gases (helium, nitrogen, argon, carbon dioxide). Collision cross sections were plotted against drift gas polarizability and a linear relationship was found for the nineteen compounds evaluated in the study. Based on the reduced mobility database, all nineteen compounds could be separated in one of the four drift gases, however, the drift gas that provided optimal separation was specific for the two compounds.

Low complexity lossless compression of underwater sound recordings.

PubMed

Johnson, Mark; Partan, Jim; Hurst, Tom

2013-03-01

Autonomous listening devices are increasingly used to study vocal aquatic animals, and there is a constant need to record longer or with greater bandwidth, requiring efficient use of memory and battery power. Real-time compression of sound has the potential to extend recording durations and bandwidths at the expense of increased processing operations and therefore power consumption. Whereas lossy methods such as MP3 introduce undesirable artifacts, lossless compression algorithms (e.g., flac) guarantee exact data recovery. But these algorithms are relatively complex due to the wide variety of signals they are designed to compress. A simpler lossless algorithm is shown here to provide compression factors of three or more for underwater sound recordings over a range of noise environments. The compressor was evaluated using samples from drifting and animal-borne sound recorders with sampling rates of 16-240 kHz. It achieves >87% of the compression of more-complex methods but requires about 1/10 of the processing operations resulting in less than 1 mW power consumption at a sampling rate of 192 kHz on a low-power microprocessor. The potential to triple recording duration with a minor increase in power consumption and no loss in sound quality may be especially valuable for battery-limited tags and robotic vehicles.

Straight-line drift fences and pitfall traps

USGS Publications Warehouse

Corn, Paul Stephen

1994-01-01

Straight-line drift fences typically are short barriers (5-15 m) that direct animals traveling on the substrate surface into traps places at the ends of or beside the barriers. Traps (described below) can be pitfalls, funnel traps, or a combination of the two. Drift fences with pitfall or funnel traps and pitfall traps without fences are used commonly to inventory and monitor populations of amphibians and reptiles. For example, 9 of 17 field studies reported for management of terrestrial vertebrates (Sarzo et al. 1988) used these techniques to sample amphibians. Drift fences with pitfall traps can be used to determine species richness at a site and to detect the presence of rare species. They also can yield data on relative abundances and habitat use of selected species. Pitfall traps arrayed in a grid without fences can also be used to study the population ecology and habitat use of selected species. Population density can be estimated with this latter technique if used in conjunction with mark-recapture techniques (see Chapter 8). Drift fence arrays or pitfall grids can be left in place for long-term monitoring. In this section, I discuss the use of this technique to obtain data on amphibians away from breeding ponds. Use of drift fences and traps to monitory amphibian activity at breeding ponds is discussed in the section "Drift Fences Encircling Breeding Sits", below (technique 9). Some materials and procedures are common to both techniques. Investigators contemplating the use of drift fences and traps in any context should read both accounts.

Dike/Drift Interactions

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

E. Gaffiney

2004-11-23

This report presents and documents the model components and analyses that represent potential processes associated with propagation of a magma-filled crack (dike) migrating upward toward the surface, intersection of the dike with repository drifts, flow of magma in the drifts, and post-magma emplacement effects on repository performance. The processes that describe upward migration of a dike and magma flow down the drift are referred to as the dike intrusion submodel. The post-magma emplacement processes are referred to as the post-intrusion submodel. Collectively, these submodels are referred to as a conceptual model for dike/drift interaction. The model components and analyses ofmore » the dike/drift interaction conceptual model provide the technical basis for assessing the potential impacts of an igneous intrusion on repository performance, including those features, events, and processes (FEPs) related to dike/drift interaction (Section 6.1).« less

Fast Ion extraction from the MedEBIS

NASA Astrophysics Data System (ADS)

Höltermann, H.; Becker, R.; Kleinod, M.; Müller, I.

2004-01-01

Cancer therapy synchrotrons profit from single turn injection in terms of size, costs and easy operation. The MEdically Dedicated EBIS (MEDEBIS), built in Frankfurt, will deliver short (~1.5 µs) and intense (~1.3 mA) pulses of highly charged light ions (C, N, O) to meet the requirements for therapy facilities. The MEDEBIS operates with an electron beam of 400 mA at 5 keV and a ratio of beam to drift tube of 1/20. Drift tube potentials up to 1.6 kV are switched in some 100 ns to deliver a 1.5 µs ion pulse at an axial field gradient of 6.5 kV/m. On extraction, all potentials applied to the drift tubes are set to a given primary potential to define the extraction gradient. During extraction the drift tubes are not held at constant voltage to avoid spreading out of the pulse due to the restoration of the full space charge depression at locations where ions have already been extracted. To locally distribute the action of the applied potentials the drift tubes are fully interpenetrating each other with tapered fingers. Combining these features result in a potential wall, which follows the extracted ion pulse and produces a compressed short ion pulse for single turn injection. In the future similar constructions could be considered for the RHIS EBIS device or proposed for LHC to provide the advantage with respect to lowest emittance and highest luminosity to the accelerators at BNL and CERN.

Electronics for fast ion extraction from EBIS devices

NASA Astrophysics Data System (ADS)

Höltermann, H.; Becker, R.; Kleinod, M.; Müller, I.

2004-05-01

Future synchrotrons for cancer therapy could profit from single turn injection in terms of size, costs, and ease of operation [O. Kester, R. Becker, and M. Kleinod, Rev. Sci. Instrum. 67 (1996)]. Short (˜1.5 μs) and intense (˜1.3 mA) pulses of highly charged light ions (C6+, N7+, O8+) are a requirement for these future therapy facilities which can be provided by an EBIS ion source. Such a medically dedicated EBIS has an electron beam of 400 mA at 5 keV and needs an electron current density of 100 A/cm2 for a repetition rate of 10 Hz. To obtain a 1.5 μs ion pulse it is necessary to switch the drift tube potentials up to 1.6 kV (for a ratio of beam to drift tube of 1/20) in some 100 ns. To avoid spreading out of the pulse due to the restoration of the full space charge depression at locations where ions have already been extracted, the potentials applied to the drift tubes are changed with time. They will be adjusted for each drift tube according to the transit time of the ion pulse. Furthermore, the drift tubes are fully interpenetrating each other with tapered fingers in order to locally distribute the action of the applied potentials. This provides a potential wall, which is following the extracted ion pulse and results in a compressed short ion pulse for single turn injection into a synchrotron.

IN SITU FIELD TESTING OF PROCESSES

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

J.S.Y. YANG

2004-11-08

The purpose of this scientific analysis report is to update and document the data and subsequent analyses from ambient field-testing activities performed in underground drifts and surface-based boreholes through unsaturated zone (UZ) tuff rock units. In situ testing, monitoring, and associated laboratory studies are conducted to directly assess and evaluate the waste emplacement environment and the natural barriers to radionuclide transport at Yucca Mountain. This scientific analysis report supports and provides data to UZ flow and transport model reports, which in turn contribute to the Total System Performance Assessment (TSPA) of Yucca Mountain, an important document for the license applicationmore » (LA). The objectives of ambient field-testing activities are described in Section 1.1. This report is the third revision (REV 03), which supercedes REV 02. The scientific analysis of data for inputs to model calibration and validation as documented in REV 02 were developed in accordance with the Technical Work Plan (TWP) ''Technical Work Plan for: Performance Assessment Unsaturated Zone'' (BSC 2004 [DIRS 167969]). This revision was developed in accordance with the ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Section 1.2.4) for better integrated, consistent, transparent, traceable, and more complete documentation in this scientific analysis report and associated UZ flow and transport model reports. No additional testing or analyses were performed as part of this revision. The list of relevant acceptance criteria is provided by ''Technical Work Plan for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654]), Table 3-1. Additional deviations from the TWP regarding the features, events, and processes (FEPs) list are discussed in Section 1.3. Documentation in this report includes descriptions of how, and under what conditions, the tests were conducted. The descriptions and analyses provide data useful for refining and confirming the understanding of flow, drift seepage, and transport processes in the UZ. The UZ testing activities included measurement of permeability distribution, quantification of the seepage of water into the drifts, evaluation of fracture-matrix interaction, study of flow along faults, testing of flow and transport between drifts, characterization of hydrologic heterogeneity along drifts, estimation of drying effects on the rock surrounding the drifts due to ventilation, monitoring of moisture conditions in open and sealed drifts, and determination of the degree of minimum construction water migration below drift. These field tests were conducted in two underground drifts at Yucca Mountain, the Exploratory Studies Facility (ESF) drift, and the cross-drift for Enhanced Characterization of the Repository Block (ECRB), as described in Section 1.2. Samples collected in boreholes and underground drifts have been used for additional hydrochemical and isotopic analyses for additional understanding of the UZ setting. The UZ transport tests conducted at the nearby Busted Butte site (see Figure 1-4) are also described in this scientific analysis report.« less

Use of reinforced inorganic cement materials for spark wire and drift chamber wire frames

NASA Technical Reports Server (NTRS)

1987-01-01

The results of a survey, materials test, and analysis study directed toward the development of an inorganic glass-fiber reinforced cement material for use in the construction of space qualified spark wire frames and drift chamber frames are presented. The purpose for this research was to evaluate the feasibility of using glass fiber reinforced cement (GFRC) for large dimensioned structural frames for supporting a number of precisely located spark wires in multiple planes. A survey of the current state of the art in fiber reinforced cement materials was made; material sample mixes were made and tested to determine their laboratory performances. Tests conducted on sample materials showed that compressive and flexural strengths of this material could approach values which would enable fabrication of structural spark wire frames.

Effects of ULF waves on local and global energetic particles: Particle energy and species dependences

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

Li, L. Y.; Yu, J.; Cao, J. B.

After 06:13 UT on 24 August 2005, an interplanetary shock triggers large-amplitude ultralow-frequency (ULF) waves (|δB| ≥ 15 nT) in the Pc4–Pc5 wave band (1.6–9 mHz) near the noon geosynchronous orbit (6.6 RE). The local and global effects of ULF waves on energetic particles are observed by five Los Alamos National Laboratory satellites at different magnetic local times. The large-amplitude ULF waves cause the synchronous oscillations of energetic electrons and protons (≥75 keV) at the noon geosynchronous orbit. When the energetic particles have a negative phase space density radial gradient, they undergo rapid outward radial diffusion and loss in themore » wave activity region. In the particle drift paths without strong ULF waves, only the rapidly drifting energetic electrons (≥225 keV) display energy-dispersive oscillations and flux decays, whereas the slowly drifting electrons (<225 keV) and protons (75–400 keV) have no ULF oscillation and loss feature. When the dayside magnetopause is compressed to the geosynchronous orbit, most of energetic electrons and protons are rapidly lost because of open drift trajectories. Furthermore, the global and multicomposition particle measurements demonstrate that the effect of ULF waves on nonlocal particle flux depends on the particle energy and species, whereas magnetopause shadowing effect is independent of the energetic particle species. For the rapidly drifting outer radiation belt particles (≥225 keV), nonlocal particle loss/acceleration processes could also change their fluxes in the entire drift trajectory in the absence of “ Dst effect” and substorm injection.« less

Effects of ULF waves on local and global energetic particles: Particle energy and species dependences

DOE PAGES

Li, L. Y.; Yu, J.; Cao, J. B.; ...

2016-11-05

After 06:13 UT on 24 August 2005, an interplanetary shock triggers large-amplitude ultralow-frequency (ULF) waves (|δB| ≥ 15 nT) in the Pc4–Pc5 wave band (1.6–9 mHz) near the noon geosynchronous orbit (6.6 RE). The local and global effects of ULF waves on energetic particles are observed by five Los Alamos National Laboratory satellites at different magnetic local times. The large-amplitude ULF waves cause the synchronous oscillations of energetic electrons and protons (≥75 keV) at the noon geosynchronous orbit. When the energetic particles have a negative phase space density radial gradient, they undergo rapid outward radial diffusion and loss in themore » wave activity region. In the particle drift paths without strong ULF waves, only the rapidly drifting energetic electrons (≥225 keV) display energy-dispersive oscillations and flux decays, whereas the slowly drifting electrons (<225 keV) and protons (75–400 keV) have no ULF oscillation and loss feature. When the dayside magnetopause is compressed to the geosynchronous orbit, most of energetic electrons and protons are rapidly lost because of open drift trajectories. Furthermore, the global and multicomposition particle measurements demonstrate that the effect of ULF waves on nonlocal particle flux depends on the particle energy and species, whereas magnetopause shadowing effect is independent of the energetic particle species. For the rapidly drifting outer radiation belt particles (≥225 keV), nonlocal particle loss/acceleration processes could also change their fluxes in the entire drift trajectory in the absence of “ Dst effect” and substorm injection.« less

Numerical modeling and experiments by forming electron beam for relativistic klystron on linear induction accelerator

NASA Astrophysics Data System (ADS)

Furman, Edvin G.; Isakov, Petr Y.; Sulakshin, Alexander S.; Vasil'ev, Vasilii V.

1995-09-01

The results of numercial modeling and experimental investigations of the linear induction accelerator operation where relativistic clystron is applied as a load are presented. The electron gun with the dielectric emitter (DE) is employed as the injector for this system. As a result of this investigation, the electro-optical system has been successfully realized allowing us to form electron beams sufficiently homogeneous in cross-section with current level of no less than 150 A. Compression of the beam from DE at the first stage of moving is supported, essentially, due to a system of focusing electrodes, similar to Pierce optics. Then, compression of the beam to the size required for its free motion in the anode tract and clystron's drift tube occurs in increasing external magnetic field. In this purpose, the configuration of tracking magnetic field was calculated and suitable magnetic system has been made. The results obtained experimentally are in good agreement with calculated data. With emitting dielectric surface of 50mm in diameter the laminar electron beam of 8mm in diameter was obtained. At accelerating voltage of 400kV and pulse duration of 120ns, required for the excitation of the X-band clystron amplifier the value of current was of the order of 200 A. Prints of the beam on targets allow us to make the same findings.

Electron transport parameters in NF3

NASA Astrophysics Data System (ADS)

Lisovskiy, V.; Yegorenkov, V.; Ogloblina, P.; Booth, J.-P.; Martins, S.; Landry, K.; Douai, D.; Cassagne, V.

2014-03-01

We present electron transport parameters (the first Townsend coefficient, the dissociative attachment coefficient, the fraction of electron energy lost by collisions with NF3 molecules, the average and characteristic electron energy, the electron mobility and the drift velocity) in NF3 gas calculated from published elastic and inelastic electron-NF3 collision cross-sections using the BOLSIG+ code. Calculations were performed for the combined RB (Rescigno 1995 Phys. Rev. E 52 329, Boesten et al 1996 J. Phys. B: At. Mol. Opt. Phys. 29 5475) momentum-transfer cross-section, as well as for the JB (Joucoski and Bettega 2002 J. Phys. B: At. Mol. Opt. Phys. 35 783) momentum-transfer cross-section. In addition, we have measured the radio frequency (rf) breakdown curves for various inter-electrode gaps and rfs, and from these we have determined the electron drift velocity in NF3 from the location of the turning point in these curves. These drift velocity values are in satisfactory agreement with those calculated by the BOLSIG+ code employing the JB momentum-transfer cross-section.

Sedimentary processes on the northwestern Iberian continental margin viewed by long-range side-scan sonar and seismic data

USGS Publications Warehouse

Gardner, James V.; Kidd, Robert B.

1987-01-01

The effects of an eastern boundary current in the North Atlantic have been mapped from about 39° north latitude along the Iberian margin to as far north as 43°30 north latitude at the western margin of Galicia Bank. The geostrophic current has produced sediment drifts that are covered with bedforms. The sediment drifts are difficult to detect on Gloria long-range side-scan sonar data but are easily resolved on seismic-reflection records as anomalously thick accumulations of sediment banked against either buried or outcropping basement highs. The bedforms ornamenting the drift surfaces were subdivided into 1,000-m water-depth intervals, and their dimensions were tabulated. There are few bedforms in water depths less han 2,000 m, but from depths between 2,000 and 4,000 m they are numerous and have a mean wavelength of 695 m. Bedforms from depths greater than 4,000 m have a mean wavelength of 999 m. The different wavelengths from different water depths suggest two distinct and separated boundary flows. The wave heights of all bedforms found in water depths greater than 2,000 m are less than 10 m. In order to investigate the continuity of sediment drifting through geological time, the stratigraphic section drilled at DSDP Site 398 was reinterpreted and, using seismic-reflection profiles, was traced throughout the northern Iberian margin. Together, the lithostratigraphic and seismic data indicate that sediment drifting developed along this margin in the Eocene. The lithofacies of the Eocene section is t e oldest to have numerous layers of sand and silt. An unconformity separates the Eocene section from the latest Miocene-Pliocene section. The unconformity is interpreted to be the result of the initial pulses of Mediterranean outflow that followed the Messinian desiccation events. A second period of sediment drifting commenced during the Pliocene once the Mediterranean basin filled and the flow out of the Strait of Gibraltar resumed.

Infrared Chemiluminescence Studies of Ion-Molecule Reactions in a Flowing Afterglow.

DTIC Science & Technology

1982-01-01

reaction rate constants and branching ratios have been addressed in drift tubes and flow drift systems, and the translational energy distribution of atomic...composed of about 40 thin cylindrical sections of flow tube , separated by mylar spacers and connected by precision resistors. In the region of LIF... tube radius (Albritton, 1967). For proper operation of a drift tube , ionic species of only one polarity can be present. Efficient separation of

The effects of nonuniform magnetic field strength on density flux and test particle transport in drift wave turbulence

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

Dewhurst, J. M.; Hnat, B.; Dendy, R. O.

2009-07-15

The extended Hasegawa-Wakatani equations generate fully nonlinear self-consistent solutions for coupled density n and vorticity {nabla}{sup 2}{phi}, where {phi} is electrostatic potential, in a plasma with background density inhomogeneity {kappa}=-{partial_derivative} ln n{sub 0}/{partial_derivative}x and magnetic field strength inhomogeneity C=-{partial_derivative} ln B/{partial_derivative}x. Finite C introduces interchange effects and {nabla}B drifts into the framework of drift turbulence through compressibility of the ExB and diamagnetic drifts. This paper addresses the direct computation of the radial ExB density flux {gamma}{sub n}=-n{partial_derivative}{phi}/{partial_derivative}y, tracer particle transport, the statistical properties of the turbulent fluctuations that drive {gamma}{sub n} and tracer motion, and analytical underpinnings. Systematic trends emergemore » in the dependence on C of the skewness of the distribution of pointwise {gamma}{sub n} and in the relative phase of density-velocity and density-potential pairings. It is shown how these effects, together with conservation of potential vorticity {pi}={nabla}{sup 2}{phi}-n+({kappa}-C)x, account for much of the transport phenomenology. Simple analytical arguments yield a Fickian relation {gamma}{sub n}=({kappa}-C)D{sub x} between the radial density flux {gamma}{sub n} and the radial tracer diffusivity D{sub x}, which is shown to explain key trends in the simulations.« less

Ensemble sea ice forecast for predicting compressive situations in the Baltic Sea

NASA Astrophysics Data System (ADS)

Lehtiranta, Jonni; Lensu, Mikko; Kokkonen, Iiro; Haapala, Jari

2017-04-01

Forecasting of sea ice hazards is important for winter shipping in the Baltic Sea. In current numerical models the ice thickness distribution and drift are captured well, but compressive situations are often missing from forecast products. Its inclusion is requested by the shipping community, as compression poses a threat to ship operations. As compressing ice is capable of stopping ships for days and even damaging them, its inclusion in ice forecasts is vital. However, we have found that compression can not be predicted well in a deterministic forecast, since it can be a local and a quickly changing phenomenon. It is also very sensitive to small changes in the wind speed and direction, the prevailing ice conditions, and the model parameters. Thus, a probabilistic ensemble simulation is needed to produce a meaningful compression forecast. An ensemble model setup was developed in the SafeWIN project for this purpose. It uses the HELMI multicategory ice model, which was amended for making simulations in parallel. The ensemble was built by perturbing the atmospheric forcing and the physical parameters of the ice pack. The model setup will provide probabilistic forecasts for the compression in the Baltic sea ice. Additionally the model setup provides insight into the uncertainties related to different model parameters and their impact on the model results. We have completed several hindcast simulations for the Baltic Sea for verification purposes. These results are shown to match compression reports gathered from ships. In addition, an ensemble forecast is in preoperational testing phase and its first evaluation will be presented in this work.

Drift-Scale Coupled Processes (DST and THC Seepage) Models

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

P. Dixon

The purpose of this Model Report (REV02) is to document the unsaturated zone (UZ) models used to evaluate the potential effects of coupled thermal-hydrological-chemical (THC) processes on UZ flow and transport. This Model Report has been developed in accordance with the ''Technical Work Plan for: Performance Assessment Unsaturated Zone'' (Bechtel SAIC Company, LLC (BSC) 2002 [160819]). The technical work plan (TWP) describes planning information pertaining to the technical scope, content, and management of this Model Report in Section 1.12, Work Package AUZM08, ''Coupled Effects on Flow and Seepage''. The plan for validation of the models documented in this Model Reportmore » is given in Attachment I, Model Validation Plans, Section I-3-4, of the TWP. Except for variations in acceptance criteria (Section 4.2), there were no deviations from this TWP. This report was developed in accordance with AP-SIII.10Q, ''Models''. This Model Report documents the THC Seepage Model and the Drift Scale Test (DST) THC Model. The THC Seepage Model is a drift-scale process model for predicting the composition of gas and water that could enter waste emplacement drifts and the effects of mineral alteration on flow in rocks surrounding drifts. The DST THC model is a drift-scale process model relying on the same conceptual model and much of the same input data (i.e., physical, hydrological, thermodynamic, and kinetic) as the THC Seepage Model. The DST THC Model is the primary method for validating the THC Seepage Model. The DST THC Model compares predicted water and gas compositions, as well as mineral alteration patterns, with observed data from the DST. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal-loading conditions, and predict the evolution of mineral alteration and fluid chemistry around potential waste emplacement drifts. The DST THC Model is used solely for the validation of the THC Seepage Model and is not used for calibration to measured data.« less

Pulsed electron beam propagation in gases under pressure of 6.6 kPa in drift tube

NASA Astrophysics Data System (ADS)

Kholodnaya, G. E.; Sazonov, R. V.; Ponomarev, D. V.; Remnev, G. E.; Poloskov, A. V.

2017-02-01

This paper presents the results of an investigation of pulsed electron beam transport propagated in a drift tube filled with different gases (He, H2, N2, Ar, SF6, and CO2). The total pressure in the drift tube was 6.6 kPa. The experiments were carried out using a TEA-500 pulsed electron accelerator. The electron beam was propagated in the drift tube composed of two sections equipped with reverse current shunts. Under a pressure of 6.6 kPa, the maximum value of the electron beam charge closed on the walls of the drift tube was recorded when the beam was propagated in hydrogen and carbon dioxide. The minimum value of the electron beam charge closed on the walls of the drift tube was recorded for sulfur hexafluoride. The visualization of the pulsed electron beam energy losses onto the walls of the drift chamber was carried out using radiation-sensitive film.

Long-Term Stability of the SGA-WZ Strapdown Airborne Gravimeter

PubMed Central

Cai, Shaokun; Zhang, Kaidong; Wu, Meiping; Huang, Yangming

2012-01-01

Accelerometers are one of the most important sensors in a strapdown airborne gravimeter. The accelerometer's drift determines the long-term accuracy of the strapdown inertial navigation system (SINS), which is the primary and most critical component of the strapdown airborne gravimeter. A long-term stability test lasting 104 days was conducted to determine the characteristics of the strapdown airborne gravimeter's long-term drift. This stability test was based on the first set of strapdown airborne gravimeters built in China, the SGA-WZ. The test results reveal a quadratic drift in the strapdown airborne gravimeter data. A drift model was developed using the static data in the two end sections, and then this model was used to correct the test data. After compensating for the drift, the drift effect improved from 70 mGal to 3.46 mGal with a standard deviation of 0.63 mGal. The quadratic curve better reflects the drift's real characteristics. In comparison with other methodologies, modelling the drift as a quadratic curve was shown to be more appropriate. Furthermore, this method allows the drift to be adjusted throughout the course of the entire campaign. PMID:23112647

Calibration of cathode strip gains in multiwire drift chambers of the GlueX experiment

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

Berdnikov, V. V.; Somov, S. V.; Pentchev, L.

A technique for calibrating cathode strip gains in multiwire drift chambers of the GlueX experiment is described. The accuracy of the technique is estimated based on Monte Carlo generated data with known gain coefficients in the strip signal channels. One of the four detector sections has been calibrated using cosmic rays. Results of drift chamber calibration on the accelerator beam upon inclusion in the GlueX experimental setup are presented.

Invertebrate drift during in-channel gravel mining: the Upper River Cinca (Southern Pyrenees)

NASA Astrophysics Data System (ADS)

Béjar, Maria; Gibbins, Chris; Vericat, Damià; Batalla, Ramon J.; Muñoz, Efrén; Ramos, Ester; Lobera, Gemma; Andrés López-Tarazón, Jose; Piqué, Gemma; Tena, Álvaro; Buendía, Cristina; Rennie, Colin D.

2015-04-01

Invertebrate drift has been widely studied as an important mechanism to structure the benthic assemblages and as a part of invertebrate behavior in fluvial systems. River channel disturbance is considered the main factor affecting the organization of riverine communities and contributes to key ecological processes. However, little is known about involuntary drift associated to bed disturbance due to the difficulties associated with sampling during floods. In-channel gravel mining offers an opportunity to study involuntary drift associated not only to local bed disturbances but also to sudden changes on suspended sediment concentrations and flow. High suspended sediment concentrations and sudden changes in flow also prompt drift due to the limiting conditions (i.e. lack of oxygen, hydric stress). Within this context, invertebrate drift was monitored in the Upper River Cinca (Southern Pyrenees) during two gravel mining activities performed in summer 2014. The data acquisition design includes: drift, suspended sediment, bedload, bed mobility and flow. Data was acquired before, during and after mining at different sampling locations located upstream and downstream the perturbation. Drift and suspended sediment transport were sampled at 5 sections: 1 control site upstream the mining and 4 downstream. Bedload samples were collected just downstream the channel where gravels were extracted. Bed mobility and changes on topography were assessed by means of GPS-aDcp and repeat topographic surveys. Discharge was continuously recorded 2.5 km downstream the mining location. Additionally, two turbidity meters registered water turbidity at 15 minute intervals in two of the four sampling sections located downstream. This experimental design provides data on the spatial and temporal variability of drift associated to a local bed disturbance that (i) changes the distribution of flow across the section where mining was performed, (ii) increase substantially suspended sediment transport, and (iii) generates bed mobility and changes on local morphology and roughness that, ultimately, modify channel topography. Samples are being post-processed. Preliminary results show markedly differences in drift in terms of densities and species at different temporal and spatial scales. These differences can be attributed to the type of disturbance during mining: (i) hydric stress associated to changes on the distribution of flows, (ii) the sudden increase of suspended sediment concentrations, or (iii) high bed mobility just downstream from the mining location. These results will provide: (a) a new framework to understand ecological responses during river disturbances and (b) key information or guidelines for an appropriate management in human stressed fluvial systems.

46 CFR 112.50-7 - Compressed air starting.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Compressed air starting. 112.50-7 Section 112.50-7... air starting. A compressed air starting system must meet the following: (a) The starting, charging... air compressors addressed in paragraph (c)(3)(i) of this section. (b) The compressed air starting...

46 CFR 112.50-7 - Compressed air starting.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Compressed air starting. 112.50-7 Section 112.50-7... air starting. A compressed air starting system must meet the following: (a) The starting, charging... air compressors addressed in paragraph (c)(3)(i) of this section. (b) The compressed air starting...

Negative viscosity from negative compressibility and axial flow shear stiffness in a straight magnetic field

DOE PAGES

Li, J. C.; Diamond, P. H.

2017-03-23

Here, negative compressibility ITG turbulence in a linear plasma device (CSDX) can induce a negative viscosity increment. However, even with this negative increment, we show that the total axial viscosity remains positive definite, i.e. no intrinsic axial flow can be generated by pure ITG turbulence in a straight magnetic field. This differs from the case of electron drift wave (EDW) turbulence, where the total viscosity can turn negative, at least transiently. When the flow gradient is steepened by any drive mechanism, so that the parallel shear flow instability (PSFI) exceeds the ITG drive, the flow profile saturates at a level close to the value above which PSFI becomes dominant. This saturated flow gradient exceeds the PSFI linear threshold, and grows withmore » $$\

Drift effect and "negative" mass transport in an inhomogeneous medium: limiting case of a two-component lattice gas.

PubMed

Lukyanets, Sergei P; Kliushnychenko, Oleksandr V

2010-11-01

The mass transport in an inhomogeneous medium is modeled as the limiting case of a two-component lattice gas with excluded volume constraint and one of the components fixed. In the long-wavelength approximation, the density relaxation of mobile particles is governed by diffusion and interaction with a medium inhomogeneity represented by the static component distribution. It is shown that the density relaxation can be locally accompanied by density distribution compression, i.e., the local mass transport directed from low-to high-density regions. The origin of such a "negative" mass transport is shown to be associated with the presence of a stationary drift flow defined by the medium inhomogeneity. In the quasi-one-dimensional case, the compression dynamics manifests itself in the hoppinglike motion of packet front position of diffusing substance due to staged passing through inhomogeneity barriers, and it leads to fragmentation of the packet and retardation of its spreading. The root-mean-square displacement reflects only the averaged packet front dynamics and becomes inappropriate as the transport characteristic in this regime. In the stationary case, the mass transport throughout the whole system may be directed from the boundary with lower concentration towards the boundary with higher concentration. Implications of the excluded volume constraint and particle distinguishability for these effects are discussed.

Compression member response of steel angle on truss structure with variation of single and double sections

NASA Astrophysics Data System (ADS)

Panjaitan, Arief; Hasibuan, Purwandy

2018-05-01

Implementation of an axial compression load on the steel angle can be found at the various structure such as truss system on telecommunication tower. For telecommunication tower, steel angle section can be suggested as an alternative solution due to its assembling easiness as well as its strength. But, antennas and microwaves installation that keep increases every time on this structure demand reinforcement on each leg of the tower structure. One solution suggested is reinforcement with increasing areas section capacity, where tower leg consisted of single angle section will be reinforced to be double angle section. Regarding this case, this research discussed the behavior of two types of steel angle section: single angle of L.30.30.3 and double angles of 2L.30.30.3. These two sections were designed identically in length (103 cm) and tested by axial compression load. At the first step, compression member together with tension member was formed to be a truss system, where compression and tension member were met at a joint plate. Schematic loading was implemented by giving tension loading on the joint plate until failure of specimens. Experimental work findings showed that implementing double angle sections (103 cm) significantly increased compression capacity of steel angle section up to 118 %.

Electron dropout echoes induced by interplanetary shock: Van Allen Probes observations

DOE PAGES

Hao, Y. X.; Zong, Q. -G.; Zhou, X. -Z.; ...

2016-06-07

On 23 November 2012, a sudden dropout of the relativistic electron flux was observed after an interplanetary shock arrival. The dropout peaks at ~1 MeV and more than 80% of the electrons disappeared from the drift shell. Van Allen twin Probes observed a sharp electron flux dropout with clear energy dispersion signals. The repeating flux dropout and recovery signatures, or “dropout echoes”, constitute a new phenomenon referred to as a “drifting electron dropout” with a limited initial spatial range. The azimuthal range of the dropout is estimated to be on the duskside, from ~1300 to 0100 LT. We then concludemore » that the shock-induced electron dropout is not caused by the magnetopause shadowing. Furthermore, the dropout and consequent echoes suggest that the radial migration of relativistic electrons is induced by the strong dusk-dawn asymmetric interplanetary shock compression on the magnetosphere.« less

Method for closing a drift between adjacent in situ oil shale retorts

DOEpatents

Hines, Alex E.

1984-01-01

A row of horizontally spaced-apart in situ oil shale retorts is formed in a subterranean formation containing oil shale. Each row of retorts is formed by excavating development drifts at different elevations through opposite side boundaries of a plurality of retorts in the row of retorts. Each retort is formed by explosively expanding formation toward one or more voids within the boundaries of the retort site to form a fragmented permeable mass of formation particles containing oil shale in each retort. Following formation of each retort, the retort development drifts on the advancing side of the retort are closed off by covering formation particles within the development drift with a layer of crushed oil shale particles having a particle size smaller than the average particle size of oil shale particles in the adjacent retort. In one embodiment, the crushed oil shale particles are pneumatically loaded into the development drift to pack the particles tightly all the way to the top of the drift and throughout the entire cross section of the drift. The closure between adjacent retorts provided by the finely divided oil shale provides sufficient resistance to gas flow through the development drift to effectively inhibit gas flow through the drift during subsequent retorting operations.

On the use of drift bottle and seabed drifter data in coastal management

NASA Technical Reports Server (NTRS)

Welch, C. S.; Norcross, J. J.

1973-01-01

The use of drift bottle and seabed drifter information for use in coastal management is discussed. The drift bottle/seabed drifter portion of VIMS project MACONS (Mid Atlantic Continental Shelf) is described as an example of how a comprehensive survey using drift bottles and seabed drifters provides data useful for coastal management. The data from MACONS are analyzed to answer specific questions of interest to several different coastal managers: a manager siting a deep oil port, one siting a sewage outfall, a manager responsible for setting up emergency beach protection procedures before an accident occurs, and a manager responsible for the environmental quality of a particular small section of coastline.

Control Infrastructure for a Pulsed Ion Accelerator

NASA Astrophysics Data System (ADS)

Persaud, A.; Regis, M. J.; Stettler, M. W.; Vytla, V. K.

2016-10-01

We report on updates to the accelerator controls for the Neutralized Drift Compression Experiment II, a pulsed induction-type accelerator for heavy ions. The control infrastructure is built around a LabVIEW interface combined with an Apache Cassandra backend for data archiving. Recent upgrades added the storing and retrieving of device settings into the database, as well as ZeroMQ as a message broker that replaces LabVIEW's shared variables. Converting to ZeroMQ also allows easy access via other programming languages, such as Python.

Control Infrastructure for a Pulsed Ion Accelerator

DOE PAGES

Persaud, A.; Regis, M. J.; Stettler, M. W.; ...

2016-07-27

We report on updates to the accelerator controls for the Neutralized Drift Compression Experiment II, a pulsed induction-type accelerator for heavy ions. The control infrastructure is built around a LabVIEW interface combined with an Apache Cassandra backend for data archiving. Recent upgrades added the storing and retrieving of device settings into the database, as well as ZeroMQ as a message broker that replaces LabVIEW's shared variables. Converting to ZeroMQ also allows easy access via other programming languages, such as Python.

The role of Shabansky orbits in the generation of compression-related EMIC waves

NASA Astrophysics Data System (ADS)

McCollough, J. P.; Elkington, S. R.; Baker, D.

2009-12-01

Electromagnetic ion-cyclotron (EMIC) waves arise from temperature anisotropies in trapped warm plasma populations. In particular, EMIC waves at high L values near local noon are often found to be related to magnetospheric compression events. There are several possible mechanisms that can generate these temperature anisotropies: energizing processes, including adiabatic compression and shock-induced and radial transport; and non-energizing processes, such as drift shell splitting and the effects of off-equatorial minima on particle populations. In this work we investigate the role of off-equatorial minima in the generation of temperature anisotropies both at the magnetic equator and at higher latitudes. There are two kinds of behavior particles undergo in response: particles with high equatorial pitch angles (EPAs) are forced to execute so-called Shabanksy orbits and mirror at high latitudes without passing through the equator, and those with lower EPAs will pass through the equator with higher EPAs than before; as a result, perpendicular energies increase at the cost of parallel energies. By using a 3D particle tracing code in a tunable analytic compressed-dipole field, we parameterize the effects of Shabansky orbits on the anisotropy of the warm plasma. These results as well as evidence from simulations of a real event in which EMIC waves were observed (the compression event of 29 June 2007) are presented.

GEOMETRIC CROSS SECTIONS OF DUST AGGREGATES AND A COMPRESSION MODEL FOR AGGREGATE COLLISIONS

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

Suyama, Toru; Wada, Koji; Tanaka, Hidekazu

2012-07-10

Geometric cross sections of dust aggregates determine their coupling with disk gas, which governs their motions in protoplanetary disks. Collisional outcomes also depend on geometric cross sections of initial aggregates. In a previous paper, we performed three-dimensional N-body simulations of sequential collisions of aggregates composed of a number of sub-micron-sized icy particles and examined radii of gyration (and bulk densities) of the obtained aggregates. We showed that collisional compression of aggregates is not efficient and that aggregates remain fluffy. In the present study, we examine geometric cross sections of the aggregates. Their cross sections decrease due to compression as wellmore » as to their gyration radii. It is found that a relation between the cross section and the gyration radius proposed by Okuzumi et al. is valid for the compressed aggregates. We also refine the compression model proposed in our previous paper. The refined model enables us to calculate the evolution of both gyration radii and cross sections of growing aggregates and reproduces well our numerical results of sequential aggregate collisions. The refined model can describe non-equal-mass collisions as well as equal-mass cases. Although we do not take into account oblique collisions in the present study, oblique collisions would further hinder compression of aggregates.« less

Analysis of two-phase flow inter-subchannel mass and momentum exchanges by the two-fluid model approach

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

Ninokata, H.; Deguchi, A.; Kawahara, A.

1995-09-01

A new void drift model for the subchannel analysis method is presented for the thermohydraulics calculation of two-phase flows in rod bundles where the flow model uses a two-fluid formulation for the conservation of mass, momentum and energy. A void drift model is constructed based on the experimental data obtained in a geometrically simple inter-connected two circular channel test sections using air-water as working fluids. The void drift force is assumed to be an origin of void drift velocity components of the two-phase cross-flow in a gap area between two adjacent rods and to overcome the momentum exchanges at themore » phase interface and wall-fluid interface. This void drift force is implemented in the cross flow momentum equations. Computational results have been successfully compared to experimental data available including 3x3 rod bundle data.« less

Stretched-to-compressed-exponential crossover observed in the electrical degradation kinetics of some spinel-metallic screen-printed structures

NASA Astrophysics Data System (ADS)

Balitska, V.; Shpotyuk, O.; Brunner, M.; Hadzaman, I.

2018-02-01

Thermally-induced (170 °C) degradation-relaxation kinetics is examined in screen-printed structures composed of spinel Cu0.1Ni0.1Co1.6Mn1.2O4 ceramics with conductive Ag or Ag-Pd layered electrodes. Structural inhomogeneities due to Ag and Ag-Pd diffusants in spinel phase environment play a decisive role in non-exponential kinetics of negative relative resistance drift. If Ag migration in spinel is inhibited by Pd addition due to Ag-Pd alloy, the kinetics attains stretched exponential behavior with ∼0.58 exponent, typical for one-stage diffusion in structurally-dispersive media. Under deep Ag penetration into spinel ceramics, as for thick films with Ag-layered electrodes, the degradation kinetics drastically changes, attaining features of two-step diffusing process governed by compressed-exponential dependence with power index of ∼1.68. Crossover from stretched- to compressed-exponential kinetics in spinel-metallic structures is mapped on free energy landscape of non-barrier multi-well system under strong perturbation from equilibrium, showing transition with a character downhill scenario resulting in faster than exponential decaying.

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

Friedman, A.; Barnard, J. J.; Cohen, R. H.

The Heavy Ion Fusion Science Virtual National Laboratory(a collaboration of LBNL, LLNL, and PPPL) is using intense ion beams to heat thin foils to the"warm dense matter" regime at<~;; 1 eV, and is developing capabilities for studying target physics relevant to ion-driven inertial fusion energy. The need for rapid target heating led to the development of plasma-neutralized pulse compression, with current amplification factors exceeding 50 now routine on the Neutralized Drift Compression Experiment (NDCX). Construction of an improved platform, NDCX-II, has begun at LBNL with planned completion in 2012. Using refurbished induction cells from the Advanced Test Accelerator at LLNL,more » NDCX-II will compress a ~;;500 ns pulse of Li+ ions to ~;;1 ns while accelerating it to 3-4 MeV over ~;;15 m. Strong space charge forces are incorporated into the machine design at a fundamental level. We are using analysis, an interactive 1D PIC code (ASP) with optimizing capabilities and centroid tracking, and multi-dimensional Warpcode PIC simulations, to develop the NDCX-II accelerator. This paper describes the computational models employed, and the resulting physics design for the accelerator.« less

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

Friedman, A; Barnard, J J; Cohen, R H

The Heavy Ion Fusion Science Virtual National Laboratory (a collaboration of LBNL, LLNL, and PPPL) is using intense ion beams to heat thin foils to the 'warm dense matter' regime at {approx}< 1 eV, and is developing capabilities for studying target physics relevant to ion-driven inertial fusion energy. The need for rapid target heating led to the development of plasma-neutralized pulse compression, with current amplification factors exceeding 50 now routine on the Neutralized Drift Compression Experiment (NDCX). Construction of an improved platform, NDCX-II, has begun at LBNL with planned completion in 2012. Using refurbished induction cells from the Advanced Testmore » Accelerator at LLNL, NDCX-II will compress a {approx}500 ns pulse of Li{sup +} ions to {approx} 1 ns while accelerating it to 3-4 MeV over {approx} 15 m. Strong space charge forces are incorporated into the machine design at a fundamental level. We are using analysis, an interactive 1D PIC code (ASP) with optimizing capabilities and centroid tracking, and multi-dimensional Warpcode PIC simulations, to develop the NDCX-II accelerator. This paper describes the computational models employed, and the resulting physics design for the accelerator.« less

Cenozoic sedimentation in the Mumbai Offshore Basin: Implications for tectonic evolution of the western continental margin of India

NASA Astrophysics Data System (ADS)

Nair, Nisha; Pandey, Dhananjai K.

2018-02-01

Interpretation of multichannel seismic reflection data along the Mumbai Offshore Basin (MOB) revealed the tectonic processes that led to the development of sedimentary basins during Cenozoic evolution. Structural interpretation along three selected MCS profiles from MOB revealed seven major sedimentary sequences (∼3.0 s TWT, thick) and the associated complex fault patterns. These stratigraphic sequences are interpreted to host detritus of syn- to post rift events during rift-drift process. The acoustic basement appeared to be faulted with interspaced intrusive bodies. The sections also depicted the presence of slumping of sediments, subsidence, marginal basins, rollover anticlines, mud diapirs etc accompanied by normal to thrust faults related to recent tectonics. Presence of upthrusts in the slope region marks the locations of local compression during collision. Forward gravity modeling constrained with results from seismic and drill results, revealed that the crustal structure beneath the MOB has undergone an extensional type tectonics intruded with intrusive bodies. Results from the seismo-gravity modeling in association with litholog data from drilled wells from the western continental margin of India (WCMI) are presented here.

Force sensitive carbon nanotube arrays for biologically inspired airflow sensing

NASA Astrophysics Data System (ADS)

Maschmann, Matthew R.; Dickinson, Ben; Ehlert, Gregory J.; Baur, Jeffery W.

2012-09-01

The compressive electromechanical response of aligned carbon nanotube (CNT) arrays is evaluated for use as an artificial hair sensor (AHS) transduction element. CNT arrays with heights of 12, 75, and 225 µm are examined. The quasi-static and dynamic sensitivity to force, response time, and signal drift are examined within the range of applied stresses predicted by a mechanical model applicable to the conceptual CNT array-based AHS (0-1 kPa). Each array is highly sensitive to compressive loading, with a maximum observed gauge factor of 114. The arrays demonstrate a repeatable response to dynamic cycling after a break-in period of approximately 50 cycles. Utilizing a four-wire measurement electrode configuration, the change in contact resistance between the array and the electrodes is observed to dominate the electromechanical response of the arrays. The response time of the CNT arrays is of the order of 10 ms. When the arrays are subjected to constant stress, mechanical creep is observed that results in a signal drift that generally diminishes the responsiveness of the arrays, particularly at stress approaching 1 kPa. The results of this study serve as a preliminary proof of concept for utilizing CNT arrays as a transduction mechanism for a proposed artificial hair sensor. Such a low profile and light-weight flow sensor is expected to have application in a number of applications including navigation and state awareness of small air vehicles, similar in function to natural hair cell receptors utilized by insects and bats.

29 CFR 1910.169 - Air receivers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 5 2013-07-01 2013-07-01 false Air receivers. 1910.169 Section 1910.169 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Compressed Gas and Compressed Air Equipment § 1910.169 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other...

29 CFR 1910.169 - Air receivers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 5 2012-07-01 2012-07-01 false Air receivers. 1910.169 Section 1910.169 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Compressed Gas and Compressed Air Equipment § 1910.169 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other...

29 CFR 1910.169 - Air receivers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 5 2014-07-01 2014-07-01 false Air receivers. 1910.169 Section 1910.169 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Compressed Gas and Compressed Air Equipment § 1910.169 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other...

29 CFR 1910.169 - Air receivers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 5 2011-07-01 2011-07-01 false Air receivers. 1910.169 Section 1910.169 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Compressed Gas and Compressed Air Equipment § 1910.169 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other...

29 CFR 1910.169 - Air receivers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 5 2010-07-01 2010-07-01 false Air receivers. 1910.169 Section 1910.169 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Compressed Gas and Compressed Air Equipment § 1910.169 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other...

49 CFR 175.501 - Special requirements for oxidizers and compressed oxygen.

Code of Federal Regulations, 2012 CFR

2012-10-01

... oxygen. 175.501 Section 175.501 Transportation Other Regulations Relating to Transportation PIPELINE AND... Special requirements for oxidizers and compressed oxygen. (a) Compressed oxygen, when properly labeled Oxidizer or Oxygen, may be loaded and transported as provided in this section. Except for Oxygen...

49 CFR 175.501 - Special requirements for oxidizers and compressed oxygen.

Code of Federal Regulations, 2014 CFR

2014-10-01

... oxygen. 175.501 Section 175.501 Transportation Other Regulations Relating to Transportation PIPELINE AND... Special requirements for oxidizers and compressed oxygen. (a) Compressed oxygen, when properly labeled Oxidizer or Oxygen, may be loaded and transported as provided in this section. Except for Oxygen...

49 CFR 175.501 - Special requirements for oxidizers and compressed oxygen.

Code of Federal Regulations, 2010 CFR

2010-10-01

... oxygen. 175.501 Section 175.501 Transportation Other Regulations Relating to Transportation PIPELINE AND... Special requirements for oxidizers and compressed oxygen. (a) Compressed oxygen, when properly labeled Oxidizer or Oxygen, may be loaded and transported as provided in this section. Except for Oxygen...

49 CFR 175.501 - Special requirements for oxidizers and compressed oxygen.

Code of Federal Regulations, 2013 CFR

2013-10-01

... oxygen. 175.501 Section 175.501 Transportation Other Regulations Relating to Transportation PIPELINE AND... Special requirements for oxidizers and compressed oxygen. (a) Compressed oxygen, when properly labeled Oxidizer or Oxygen, may be loaded and transported as provided in this section. Except for Oxygen...

49 CFR 175.501 - Special requirements for oxidizers and compressed oxygen.

Code of Federal Regulations, 2011 CFR

2011-10-01

... oxygen. 175.501 Section 175.501 Transportation Other Regulations Relating to Transportation PIPELINE AND... Special requirements for oxidizers and compressed oxygen. (a) Compressed oxygen, when properly labeled Oxidizer or Oxygen, may be loaded and transported as provided in this section. Except for Oxygen...

Drift-based scrape-off particle width in X-point geometry

NASA Astrophysics Data System (ADS)

Reiser, D.; Eich, T.

2017-04-01

The Goldston heuristic estimate of the scrape-off layer width (Goldston 2012 Nucl. Fusion 52 013009) is reconsidered using a fluid description for the plasma dynamics. The basic ingredient is the inclusion of a compressible diamagnetic drift for the particle cross field transport. Instead of testing the heuristic model in a sophisticated numerical simulation including several physical mechanisms working together, the purpose of this work is to point out basic consequences for a drift-dominated cross field transport using a reduced fluid model. To evaluate the model equations and prepare them for subsequent numerical solution a specific analytical model for 2D magnetic field configurations with X-points is employed. In a first step parameter scans in high-resolution grids for isothermal plasmas are done to assess the basic formulas of the heuristic model with respect to the functional dependence of the scrape-off width on the poloidal magnetic field and plasma temperature. Particular features in the 2D-fluid calculations—especially the appearance of supersonic parallel flows and shock wave like bifurcational jumps—are discussed and can be understood partly in the framework of a reduced 1D model. The resulting semi-analytical findings might give hints for experimental proof and implementation in more elaborated fluid simulations.

Composeable Chat over Low-Bandwidth Intermittent Communication Links

DTIC Science & Technology

2007-04-01

Compression (STC), introduced in this report, is a data compression algorithm intended to compress alphanumeric... Ziv - Lempel coding, the grandfather of most modern general-purpose file compression programs, watches for input symbol sequences that have previously... data . This section applies these techniques to create a new compression algorithm called Small Text Compression . Various sequence compression

POST-PROCESSING ANALYSIS FOR THC SEEPAGE

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

Y. SUN

This report describes the selection of water compositions for the total system performance assessment (TSPA) model of results from the thermal-hydrological-chemical (THC) seepage model documented in ''Drift-Scale THC Seepage Model'' (BSC 2004 [DIRS 169856]). The selection has been conducted in accordance with ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Post-Processing Analysis for THC Seepage) Report Integration'' (BSC 2004 [DIRS 171334]). This technical work plan (TWP) was prepared in accordance with AP-2.27Q, ''Planning for Science Activities''. Section 1.2.3 of the TWP describes planning information pertaining to the technical scope, content, and managementmore » of this report. The post-processing analysis for THC seepage (THC-PPA) documented in this report provides a methodology for evaluating the near-field compositions of water and gas around a typical waste emplacement drift as these relate to the chemistry of seepage, if any, into the drift. The THC-PPA inherits the conceptual basis of the THC seepage model, but is an independently developed process. The relationship between the post-processing analysis and other closely related models, together with their main functions in providing seepage chemistry information for the Total System Performance Assessment for the License Application (TSPA-LA), are illustrated in Figure 1-1. The THC-PPA provides a data selection concept and direct input to the physical and chemical environment (P&CE) report that supports the TSPA model. The purpose of the THC-PPA is further discussed in Section 1.2. The data selection methodology of the post-processing analysis (Section 6.2.1) was initially applied to results of the THC seepage model as presented in ''Drift-Scale THC Seepage Model'' (BSC 2004 [DIRS 169856]). Other outputs from the THC seepage model (DTN: LB0302DSCPTHCS.002 [DIRS 161976]) used in the P&CE (BSC 2004 [DIRS 169860], Section 6.6) were also subjected to the same initial selection. The present report serves as a full documentation of this selection and also provides additional analyses in support of the choice of waters selected for further evaluation in ''Engineered Barrier System: Physical and Chemical Environment'' (BSC 2004 [DIRS 169860], Section 6.6). The work scope for the studies presented in this report is described in the TWP (BSC 2004 [DIRS 171334]) and other documents cited above and can be used to estimate water and gas compositions near waste emplacement drifts. Results presented in this report were submitted to the Technical Data Management System (TDMS) under specific data tracking numbers (DTNs) as listed in Appendix A. The major change from previous selection of results from the THC seepage model is that the THC-PPA now considers data selection in space around the modeled waste emplacement drift, tracking the evolution of pore-water and gas-phase composition at the edge of the dryout zone around the drift. This post-processing analysis provides a scientific background for the selection of potential seepage water compositions.« less

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

NASA Astrophysics Data System (ADS)

Kang, Hyesung; Ryu, Dongsu

2018-03-01

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

Drift-Scale THC Seepage Model

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

C.R. Bryan

The purpose of this report (REV04) is to document the thermal-hydrologic-chemical (THC) seepage model, which simulates the composition of waters that could potentially seep into emplacement drifts, and the composition of the gas phase. The THC seepage model is processed and abstracted for use in the total system performance assessment (TSPA) for the license application (LA). This report has been developed in accordance with ''Technical Work Plan for: Near-Field Environment and Transport: Coupled Processes (Mountain-Scale TH/THC/THM, Drift-Scale THC Seepage, and Post-Processing Analysis for THC Seepage) Report Integration'' (BSC 2005 [DIRS 172761]). The technical work plan (TWP) describes planning information pertainingmore » to the technical scope, content, and management of this report. The plan for validation of the models documented in this report is given in Section 2.2.2, ''Model Validation for the DS THC Seepage Model,'' of the TWP. The TWP (Section 3.2.2) identifies Acceptance Criteria 1 to 4 for ''Quantity and Chemistry of Water Contacting Engineered Barriers and Waste Forms'' (NRC 2003 [DIRS 163274]) as being applicable to this report; however, in variance to the TWP, Acceptance Criterion 5 has also been determined to be applicable, and is addressed, along with the other Acceptance Criteria, in Section 4.2 of this report. Also, three FEPS not listed in the TWP (2.2.10.01.0A, 2.2.10.06.0A, and 2.2.11.02.0A) are partially addressed in this report, and have been added to the list of excluded FEPS in Table 6.1-2. This report has been developed in accordance with LP-SIII.10Q-BSC, ''Models''. This report documents the THC seepage model and a derivative used for validation, the Drift Scale Test (DST) THC submodel. The THC seepage model is a drift-scale process model for predicting the composition of gas and water that could enter waste emplacement drifts and the effects of mineral alteration on flow in rocks surrounding drifts. The DST THC submodel uses a drift-scale process model relying on the same conceptual model and many of the same input data (i.e., physical, hydrologic, thermodynamic, and kinetic) as the THC seepage model. The DST THC submodel is the primary means for validating the THC seepage model. The DST THC submodel compares predicted water and gas compositions, and mineral alteration patterns, with observed data from the DST. These models provide the framework to evaluate THC coupled processes at the drift scale, predict flow and transport behavior for specified thermal-loading conditions, and predict the evolution of mineral alteration and fluid chemistry around potential waste emplacement drifts. The DST THC submodel is used solely for the validation of the THC seepage model and is not used for calibration to measured data.« less

Adaptive learning compressive tracking based on Markov location prediction

NASA Astrophysics Data System (ADS)

Zhou, Xingyu; Fu, Dongmei; Yang, Tao; Shi, Yanan

2017-03-01

Object tracking is an interdisciplinary research topic in image processing, pattern recognition, and computer vision which has theoretical and practical application value in video surveillance, virtual reality, and automatic navigation. Compressive tracking (CT) has many advantages, such as efficiency and accuracy. However, when there are object occlusion, abrupt motion and blur, similar objects, and scale changing, the CT has the problem of tracking drift. We propose the Markov object location prediction to get the initial position of the object. Then CT is used to locate the object accurately, and the classifier parameter adaptive updating strategy is given based on the confidence map. At the same time according to the object location, extract the scale features, which is able to deal with object scale variations effectively. Experimental results show that the proposed algorithm has better tracking accuracy and robustness than current advanced algorithms and achieves real-time performance.

MMS Observations of Ion-Scale Magnetic Island in the Magnetosheath Turbulent Plasma

NASA Technical Reports Server (NTRS)

Huang, S. Y.; Sahraoui, F.; Retino, A.; Contel, O. Le; Yuan, Z. G.; Chasapis, A.; Aunai, N.; Breuillard, H.; Deng, X. H.; Zhou, M.;

Coupled ion acoustic and drift waves in magnetized superthermal electron-positron-ion plasmas

NASA Astrophysics Data System (ADS)

Adnan, Muhammad; Mahmood, S.; Qamar, Anisa

2014-09-01

Linear and nonlinear coupled drift-ion acoustic waves are investigated in a nonuniform magnetoplasma having kappa distributed electrons and positrons. In the linear regime, the role of kappa distribution and positron content on the dispersion relation has been highlighted; it is found that strong superthermality (low value of κ) and addition of positrons lowers the phase velocity via decreasing the fundamental scalelengths of the plasmas. In the nonlinear regime, first, coherent nonlinear structure in the form of dipoles and monopoles are obtained and the boundary conditions (boundedness) in the context of superthermality and positron concentrations are discussed. Second, in case of scalar nonlinearity, a Korteweg-de Vries-type equation is obtained, which admit solitary wave solution. It is found that both compressive and rarefactive solitons are formed in the present model. The present work may be useful to understand the low frequency electrostatic modes in inhomogeneous electron positron ion plasmas, which exist in astrophysical plasma situations such as those found in the pulsar magnetosphere.

Measuring the equations of state in a relaxed magnetohydrodynamic plasma.

PubMed

Kaur, M; Barbano, L J; Suen-Lewis, E M; Shrock, J E; Light, A D; Brown, M R; Schaffner, D A

2018-01-01

We report measurements of the equations of state of a fully relaxed magnetohydrodynamic (MHD) laboratory plasma. Parcels of magnetized plasma, called Taylor states, are formed in a coaxial magnetized plasma gun, and are allowed to relax and drift into a closed flux conserving volume. Density, ion temperature, and magnetic field are measured as a function of time as the Taylor states compress and heat. The theoretically predicted MHD and double adiabatic equations of state are compared to experimental measurements. We find that the MHD equation of state is inconsistent with our data.

Measuring the equations of state in a relaxed magnetohydrodynamic plasma

NASA Astrophysics Data System (ADS)

Kaur, M.; Barbano, L. J.; Suen-Lewis, E. M.; Shrock, J. E.; Light, A. D.; Brown, M. R.; Schaffner, D. A.

2018-01-01

We report measurements of the equations of state of a fully relaxed magnetohydrodynamic (MHD) laboratory plasma. Parcels of magnetized plasma, called Taylor states, are formed in a coaxial magnetized plasma gun, and are allowed to relax and drift into a closed flux conserving volume. Density, ion temperature, and magnetic field are measured as a function of time as the Taylor states compress and heat. The theoretically predicted MHD and double adiabatic equations of state are compared to experimental measurements. We find that the MHD equation of state is inconsistent with our data.

Microbial Communities Model Parameter Calculation for TSPA/SR

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

D. Jolley

2001-07-16

This calculation has several purposes. First the calculation reduces the information contained in ''Committed Materials in Repository Drifts'' (BSC 2001a) to useable parameters required as input to MING V1.O (CRWMS M&O 1998, CSCI 30018 V1.O) for calculation of the effects of potential in-drift microbial communities as part of the microbial communities model. The calculation is intended to replace the parameters found in Attachment II of the current In-Drift Microbial Communities Model revision (CRWMS M&O 2000c) with the exception of Section 11-5.3. Second, this calculation provides the information necessary to supercede the following DTN: M09909SPAMING1.003 and replace it with a newmore » qualified dataset (see Table 6.2-1). The purpose of this calculation is to create the revised qualified parameter input for MING that will allow {Delta}G (Gibbs Free Energy) to be corrected for long-term changes to the temperature of the near-field environment. Calculated herein are the quadratic or second order regression relationships that are used in the energy limiting calculations to potential growth of microbial communities in the in-drift geochemical environment. Third, the calculation performs an impact review of a new DTN: M00012MAJIONIS.000 that is intended to replace the currently cited DTN: GS9809083 12322.008 for water chemistry data used in the current ''In-Drift Microbial Communities Model'' revision (CRWMS M&O 2000c). Finally, the calculation updates the material lifetimes reported on Table 32 in section 6.5.2.3 of the ''In-Drift Microbial Communities'' AMR (CRWMS M&O 2000c) based on the inputs reported in BSC (2001a). Changes include adding new specified materials and updating old materials information that has changed.« less

Ion-neutral potential models in atmospheric pressure ion mobility time-of-flight mass spectrometry IM(tof)MS.

PubMed

Steiner, Wes E; English, William A; Hill, Herbert H

2006-02-09

The ion mobilities and their respective masses of several classes of amines (primary, secondary, and tertiary) were measured by electrospray ionization atmospheric pressure ion mobility time-of-flight mass spectrometry IM(tof)MS. The experimental data obtained were comparatively analyzed by the one-temperature kinetic theory of Chapman-Enskog. Several theoretical models were used to estimate the collision cross-sections; they include the rigid-sphere, polarization-limit, 12-6-4, and 12-4 potential models. These models were investigated to represent the interaction potentials contained within the collision integral that occurs between the polyatomic ions and the neutral drift gas molecules. The effectiveness of these collision cross-section models on predicting the mobility of these amine ions was explored. Moreover, the effects of drift gas selectivity on the reduced-mass term and in the collision cross-section term was examined. Use of a series of drift gases, namely, helium, neon, argon, nitrogen, and carbon dioxide, made it possible to distinguish between mass effects and polarizability effects. It was found that the modified 12-4 potential that compensates for the center of charge not being at the same location as the centers of mass showed improved agreement over the other collision cross-section models with respect to experimental data.

Conformational ordering of biomolecules in the gas phase: nitrogen collision cross sections measured on a prototype high resolution drift tube ion mobility-mass spectrometer.

PubMed

May, Jody C; Goodwin, Cody R; Lareau, Nichole M; Leaptrot, Katrina L; Morris, Caleb B; Kurulugama, Ruwan T; Mordehai, Alex; Klein, Christian; Barry, William; Darland, Ed; Overney, Gregor; Imatani, Kenneth; Stafford, George C; Fjeldsted, John C; McLean, John A

2014-02-18

Ion mobility-mass spectrometry measurements which describe the gas-phase scaling of molecular size and mass are of both fundamental and pragmatic utility. Fundamentally, such measurements expand our understanding of intrinsic intramolecular folding forces in the absence of solvent. Practically, reproducible transport properties, such as gas-phase collision cross-section (CCS), are analytically useful metrics for identification and characterization purposes. Here, we report 594 CCS values obtained in nitrogen drift gas on an electrostatic drift tube ion mobility-mass spectrometry (IM-MS) instrument. The instrument platform is a newly developed prototype incorporating a uniform-field drift tube bracketed by electrodynamic ion funnels and coupled to a high resolution quadrupole time-of-flight mass spectrometer. The CCS values reported here are of high experimental precision (±0.5% or better) and represent four chemically distinct classes of molecules (quaternary ammonium salts, lipids, peptides, and carbohydrates), which enables structural comparisons to be made between molecules of different chemical compositions for the rapid "omni-omic" characterization of complex biological samples. Comparisons made between helium and nitrogen-derived CCS measurements demonstrate that nitrogen CCS values are systematically larger than helium values; however, general separation trends between chemical classes are retained regardless of the drift gas. These results underscore that, for the highest CCS accuracy, care must be exercised when utilizing helium-derived CCS values to calibrate measurements obtained in nitrogen, as is the common practice in the field.

Conformational Ordering of Biomolecules in the Gas Phase: Nitrogen Collision Cross Sections Measured on a Prototype High Resolution Drift Tube Ion Mobility-Mass Spectrometer

PubMed Central

2014-01-01

Ion mobility-mass spectrometry measurements which describe the gas-phase scaling of molecular size and mass are of both fundamental and pragmatic utility. Fundamentally, such measurements expand our understanding of intrinsic intramolecular folding forces in the absence of solvent. Practically, reproducible transport properties, such as gas-phase collision cross-section (CCS), are analytically useful metrics for identification and characterization purposes. Here, we report 594 CCS values obtained in nitrogen drift gas on an electrostatic drift tube ion mobility-mass spectrometry (IM-MS) instrument. The instrument platform is a newly developed prototype incorporating a uniform-field drift tube bracketed by electrodynamic ion funnels and coupled to a high resolution quadrupole time-of-flight mass spectrometer. The CCS values reported here are of high experimental precision (±0.5% or better) and represent four chemically distinct classes of molecules (quaternary ammonium salts, lipids, peptides, and carbohydrates), which enables structural comparisons to be made between molecules of different chemical compositions for the rapid “omni-omic” characterization of complex biological samples. Comparisons made between helium and nitrogen-derived CCS measurements demonstrate that nitrogen CCS values are systematically larger than helium values; however, general separation trends between chemical classes are retained regardless of the drift gas. These results underscore that, for the highest CCS accuracy, care must be exercised when utilizing helium-derived CCS values to calibrate measurements obtained in nitrogen, as is the common practice in the field. PMID:24446877

Compressed Sensing for Body MRI

PubMed Central

Feng, Li; Benkert, Thomas; Block, Kai Tobias; Sodickson, Daniel K; Otazo, Ricardo; Chandarana, Hersh

2016-01-01

The introduction of compressed sensing for increasing imaging speed in MRI has raised significant interest among researchers and clinicians, and has initiated a large body of research across multiple clinical applications over the last decade. Compressed sensing aims to reconstruct unaliased images from fewer measurements than that are traditionally required in MRI by exploiting image compressibility or sparsity. Moreover, appropriate combinations of compressed sensing with previously introduced fast imaging approaches, such as parallel imaging, have demonstrated further improved performance. The advent of compressed sensing marks the prelude to a new era of rapid MRI, where the focus of data acquisition has changed from sampling based on the nominal number of voxels and/or frames to sampling based on the desired information content. This paper presents a brief overview of the application of compressed sensing techniques in body MRI, where imaging speed is crucial due to the presence of respiratory motion along with stringent constraints on spatial and temporal resolution. The first section provides an overview of the basic compressed sensing methodology, including the notion of sparsity, incoherence, and non-linear reconstruction. The second section reviews state-of-the-art compressed sensing techniques that have been demonstrated for various clinical body MRI applications. In the final section, the paper discusses current challenges and future opportunities. PMID:27981664

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

Kholodnaya, G. E.; Sazonov, R. V.; Ponomarev, D. V.

The paper presents the results of current measurements for the electron beam, propagating inside a drift tube filled in with a gas mixture (Ar and N{sub 2}). The experiments were performed using the TEA-500 pulsed electron accelerator. The main characteristics of electron beam were as follows: 60 ns pulse duration, up to 200 J energy, and 5 cm diameter. The electron beam propagated inside the drift tube assembled of three sections. Gas pressures inside the drift tube were 760 ± 3, 300 ± 3, and 50 ± 1 Torr. The studies were performed in argon, nitrogen, and their mixtures of 33%, 50%, and 66% volume concentrations, respectively.

30 CFR 77.412 - Compressed air systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compressed air systems. 77.412 Section 77.412... for Mechanical Equipment § 77.412 Compressed air systems. (a) Compressors and compressed-air receivers... involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not be...

29 CFR 1917.154 - Compressed air.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 7 2013-07-01 2013-07-01 false Compressed air. 1917.154 Section 1917.154 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.154 Compressed air. Employees shall be... this part during cleaning with compressed air. Compressed air used for cleaning shall not exceed a...

30 CFR 77.412 - Compressed air systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressed air systems. 77.412 Section 77.412... for Mechanical Equipment § 77.412 Compressed air systems. (a) Compressors and compressed-air receivers... involving the pressure system of compressors, receivers, or compressed-air-powered equipment shall not be...

29 CFR 1917.154 - Compressed air.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 7 2012-07-01 2012-07-01 false Compressed air. 1917.154 Section 1917.154 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.154 Compressed air. Employees shall be... this part during cleaning with compressed air. Compressed air used for cleaning shall not exceed a...

29 CFR 1917.154 - Compressed air.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 7 2014-07-01 2014-07-01 false Compressed air. 1917.154 Section 1917.154 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.154 Compressed air. Employees shall be... this part during cleaning with compressed air. Compressed air used for cleaning shall not exceed a...

Geology of the U12n. 02 (Midi Mist) drift, and postshot observations, Rainier Mesa, Area 12, Nevada Test Site

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

Ege, J R; Danilchik, W; Feazel, C T

1980-05-01

Mining of the Ul2n.02 drift for the Midi Mist event started on December 31, 1965, in Rainier Mesa, Nevada Test Site, and was completed on December 30, 1966. The drift was mined along a bearing of S. 65/sup 0/ W. at an altitude of 1,850.2 m (6,070.2 ft) to a length of 643 m (2,109 ft). The drift lies in tunnel bed 4 and penetrates stratigraphically up the section through sub-units 4AB, 4CD, 4E, 4F, 4G, 4H, and 4J, all of Tertiary age. Two faults mapped at the surface of the mesa were identified as having cut the complex atmore » drift level. No engineering construction or support problems greater than minor rock slabbing, ravelly ground, or water inflow along fractures were uncountered. Visual inspection showed that shot-induced effects in the rock medium at drift level extended for 237.7 m (780 ft) from the working point in the form of fractures and small shear displacements along bedding planes.« less

Withdrawal of gases and liquids from an in situ oil shale retort

DOEpatents

Siegel, Martin M.

1982-01-01

An in situ oil shale retort is formed within a subterranean formation containing oil shale. The retort contains a fragmented permeable mass of formation particles containing oil shale. A production level drift extends below the fragmented mass, leaving a lower sill pillar of unfragmented formation between the production level drift and the fragmented mass. During retorting operations, liquid and gaseous products are recovered from a lower portion of the fragmented mass. A liquid outlet line extends from a lower portion of the fragmented mass through the lower sill pillar for conducting liquid products to a sump in the production level drift. Gaseous products are withdrawn from the fragmented mass through a plurality of gas outlet lines distributed across a horizontal cross-section of a lower portion of the fragmented mass. The gas outlet lines extend from the fragmented mass through the lower sill pillar and into the production level drift. The gas outlet lines are connected to a gas withdrawal manifold in the production level drift, and gaseous products are withdrawn from the manifold separately from withdrawal of liquid products from the sump in the production level drift.

Theoretical studies of defect formation and target heating by intense pulsed ion beams

NASA Astrophysics Data System (ADS)

Barnard, J. J.; Schenkel, T.; Persaud, A.; Seidl, P. A.; Friedman, A.; Grote, D. P.; Davidson, R. C.; Gilson, E. P.; Kaganovich, I.

2015-11-01

We present results of three studies related to experiments on NDCX-II, the Neutralized Drift Compression Experiment, a short-pulse (~ 1ns), high-current (~ 70A) linear accelerator for 1.2 MeV ions at LBNL. These include: (a) Coupled transverse and longitudinal envelope calculations of the final non-neutral ion beam transport, followed by neutralized drift and final focus, for a number of focus and drift lengths and with a series of ion species (Z =1-19). Predicted target fluences were obtained and target temperatures in the 1 eV range estimated. (b) HYDRA simulations of the target response for Li and He ions and for Al and Au targets at various ion fluences (up to 1012 ions/pulse/mm2) and pulse durations, benchmarking temperature estimates from the envelope calculations. (c) Crystal-Trim simulations of ion channeling through single-crystal lattices, with comparisons to ion transmission data as a function of orientation angle of the crystal foil and for different ion intensities and ion species. This work was performed under the auspices of the U.S. DOE under contracts DE-AC52-07NA27344 (LLNL), DE-AC02-05CH11231 (LBNL) and DE-AC02-76CH0307 (PPPL) and was supported by the US DOE Office of Science, Fusion Energy Sciences. LLNL-ABS-67521.

30 CFR 57.13020 - Use of compressed air.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Use of compressed air. 57.13020 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13020 Use of compressed air. At no time shall compressed air be directed toward a...

30 CFR 56.13020 - Use of compressed air.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Use of compressed air. 56.13020 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13020 Use of compressed air. At no time shall compressed air be directed toward a person...

30 CFR 57.13020 - Use of compressed air.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Use of compressed air. 57.13020 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13020 Use of compressed air. At no time shall compressed air be directed toward a...

30 CFR 56.13020 - Use of compressed air.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Use of compressed air. 56.13020 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13020 Use of compressed air. At no time shall compressed air be directed toward a person...

30 CFR 56.13020 - Use of compressed air.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Use of compressed air. 56.13020 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13020 Use of compressed air. At no time shall compressed air be directed toward a person...

30 CFR 57.13020 - Use of compressed air.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Use of compressed air. 57.13020 Section 57... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Compressed Air and Boilers § 57.13020 Use of compressed air. At no time shall compressed air be directed toward a...

30 CFR 56.13020 - Use of compressed air.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Use of compressed air. 56.13020 Section 56... MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Compressed Air and Boilers § 56.13020 Use of compressed air. At no time shall compressed air be directed toward a person...

Biphasic DC measurement approach for enhanced measurement stability and multi-channel sampling of self-sensing multi-functional structural materials doped with carbon-based additives

NASA Astrophysics Data System (ADS)

Downey, Austin; D'Alessandro, Antonella; Ubertini, Filippo; Laflamme, Simon; Geiger, Randall

2017-06-01

Investigation of multi-functional carbon-based self-sensing structural materials for structural health monitoring applications is a topic of growing interest. These materials are self-sensing in the sense that they can provide measurable electrical outputs corresponding to physical changes such as strain or induced damage. Nevertheless, the development of an appropriate measurement technique for such materials is yet to be achieved, as many results in the literature suggest that these materials exhibit a drift in their output when measured with direct current (DC) methods. In most of the cases, the electrical output is a resistance and the reported drift is an increase in resistance from the time the measurement starts due to material polarization. Alternating current methods seem more appropriate at eliminating the time drift. However, published results show they are not immune to drift. Moreover, the use of multiple impedance measurement devices (LCR meters) does not allow for the simultaneous multi-channel sampling of multi-sectioned self-sensing materials due to signal crosstalk. The capability to simultaneously monitor multiple sections of self-sensing structural materials is needed to deploy these multi-functional materials for structural health monitoring. Here, a biphasic DC measurement approach with a periodic measure/discharge cycle in the form of a square wave sensing current is used to provide consistent, stable resistance measurements for self-sensing structural materials. DC measurements are made during the measurement region of the square wave while material depolarization is obtained during the discharge region of the periodic signal. The proposed technique is experimentally shown to remove the signal drift in a carbon-based self-sensing cementitious material while providing simultaneous multi-channel measurements of a multi-sectioned self-sensing material. The application of the proposed electrical measurement technique appears promising for real-time utilization of self-sensing materials in structural health monitoring.

Evaluation and statistical judgement of neural responses to sinusoidal stimulation in cases with superimposed drift and noise.

PubMed

Jastreboff, P W

1979-06-01

Time histograms of neural responses evoked by sinuosidal stimulation often contain a slow drifting and an irregular noise which disturb Fourier analysis of these responses. Section 2 of this paper evaluates the extent to which a linear drift influences the Fourier analysis, and develops a combined Fourier and linear regression analysis for detecting and correcting for such a linear drift. Usefulness of this correcting method is demonstrated for the time histograms of actual eye movements and Purkinje cell discharges evoked by sinusoidal rotation of rabbits in the horizontal plane. In Sect. 3, the analysis of variance is adopted for estimating the probability of the random occurrence of the response curve extracted by Fourier analysis from noise. This method proved to be useful for avoiding false judgements as to whether the response curve was meaningful, particularly when the response was small relative to the contaminating noise.

Ion profiling in an ambient drift tube-ion mobility spectrometer using a high pixel density linear array detector IonCCD.

PubMed

Davila, Stephen J; Hadjar, Omar; Eiceman, Gary A

2013-07-16

A linear pixel-based detector array, the IonCCD, is characterized for use under ambient conditions with thermal (<1 eV) positive ions derived from purified air and a 10 mCi (63)Ni foil. The IonCCD combined with a drift tube-ion mobility spectrometer permitted the direct detection of gas phase ions at atmospheric pressure and confirmed a limit of detection of 3000 ions/pixel/frame established previously in both the keV (1-2 keV) and the hyper-thermal (10-40 eV) regimes. Results demonstrate the "broad-band" application of the IonCCD over 10(5) orders in ion energy and over 10(10) in operating pressure. The Faraday detector of a drift tube for an ion mobility spectrometer was replaced with the IonCCD providing images of ion profiles over the cross-section of the drift tube. Patterns in the ion profiles were developed in the drift tube cross-section by control of electric fields between wires of Bradbury Nielson and Tyndall Powell shutter designs at distances of 1-8 cm from the detector. Results showed that ion beams formed in wire sets, retained their shape with limited mixing by diffusion and Coulombic repulsion. Beam broadening determined as 95 μm/cm for hydrated protons in air with moisture of ~10 ppmv. These findings suggest a value of the IonCCD in further studies of ion motion and diffusion of thermalized ions, enhancing computational results from simulation programs, and in the design or operation of ion mobility spectrometers.

Microdefects and self-interstitial diffusion in crystalline silicon

NASA Astrophysics Data System (ADS)

Knowlton, William Barthelemy

In this thesis, a study is presented of D-defects and self-interstitial diffusion in silicon using Li ion (Lisp+) drifting in an electric field and transmission electron microscopy (TEM). Obstruction of Lisp+ drifting has been found in wafers from certain but not all FZ p-type Si. Incomplete Lisp+ drifting always occurs in the central region of the wafers. This work established that interstitial oxygen is not responsible for hindering Lisp+ drifting. The Osb i concentration was measured ({˜}2× 10sp{15}\\ cmsp{-3}) by local vibrational mode Fourier transform infrared spectroscopy and did not vary radially across the wafer. TEM was performed on a samples from the partially Lisp+ drifted area and compared to regions without D-defects. Precipitates were found only in the region containing D-defects that had partially Lisp+ drifted. This result indicates D-defects are responsible for the precipitation that halts the Lisp+ drift process. The precipitates were characterized using selected area diffraction (SAD) and image contrast analysis. The results suggested that the precipitates may cause stacking faults and their identity may be lithium silicides such as Lisb{21}Sisb5\\ and\\ Lisb{13}Sisb4. TEM revealed a decreasing distribution of Li precipitates as a function of Lisp+ drift depth along the growth direction. A preliminary model is presented that simulates Lisp+ drifting. The objective of the model is to incorporate the Li precipitate density distribution and Lisp+ drift depth to extract the size and capture cross-section of the D-defects. Nitrogen (N) doping has been shown to eliminate D-defects as measured by conventional techniques. However, Lisp+ drifting has shown that D-defects are indeed still present. Lisp+ drifting is able to detect D-defects at concentrations lower than conventional techniques. Lisp+ drifting and D-defects provide a useful means to study Si self-interstitial diffusion. The process modeling program SUPREM-IV was used to simulate the results of Si self-interstitial diffusion obtained from Lisp+ drifting experiments. Anomalous results from the Si self-interstitial diffusion experiments forced a re-examination of the possibility of thermal dissociation of D-defects. Thermal annealing experiments that were performed support this possibility. A review of the current literature illustrates the need for more research on the effects of thermal processing on FZ Si to understand the dissolution kinetics of D-defects.

46 CFR 147.60 - Compressed gases.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Compressed gases. 147.60 Section 147.60 Shipping COAST... Other Special Requirements for Particular Materials § 147.60 Compressed gases. (a) Cylinder requirements. Cylinders used for containing hazardous ships' stores that are compressed gases must be— (1) Authorized for...

Klystron having electrostatic quadrupole focusing arrangement

DOEpatents

Maschke, Alfred W.

1983-08-30

A klystron includes a source for emitting at least one electron beam, and an accelerator for accelarating the beam in a given direction through a number of drift tube sections successively aligned relative to one another in the direction of the beam. A number of electrostatic quadrupole arrays are successively aligned relative to one another along at least one of the drift tube sections in the beam direction for focusing the electron beam. Each of the electrostatic quadrupole arrays forms a different quadrupole for each electron beam. Two or more electron beams can be maintained in parallel relationship by the quadrupole arrays, thereby enabling space charge limitations encountered with conventional single beam klystrons to be overcome.

Klystron having electrostatic quadrupole focusing arrangement

DOEpatents

Maschke, A.W.

1983-08-30

A klystron includes a source for emitting at least one electron beam, and an accelerator for accelerating the beam in a given direction through a number of drift tube sections successively aligned relative to one another in the direction of the beam. A number of electrostatic quadrupole arrays are successively aligned relative to one another along at least one of the drift tube sections in the beam direction for focusing the electron beam. Each of the electrostatic quadrupole arrays forms a different quadrupole for each electron beam. Two or more electron beams can be maintained in parallel relationship by the quadrupole arrays, thereby enabling space charge limitations encountered with conventional single beam klystrons to be overcome. 4 figs.

Compression member response of double steel angles on truss structure with member length variation

NASA Astrophysics Data System (ADS)

Hasibuan, Purwandy; Panjaitan, Arief; Haiqal, Muhammad

2018-05-01

One type of structures that implements steel angles as its members is truss system of telecommunication tower. For this structure, reinforcements on tower legs are also needed when antennas and microwaves installation placed on the peak of tower increases in quantity. One type of reinforcement methods commonly used is by increasing areas section capacity, where tower leg consisted of single angle section will be reinforced to be double angle sections. Regarding this case, this research discussed behavior two types of double angle steel section 2L 30.30.3 that were designed identically in area section but vary in length: 103 cm and 83 cm. At the first step, compression member together with tension member was formed to be a truss system, where compression and tension member were met at the joint plate. Schematic loading was implemented by giving tension loading on the joint plate, and this loading was terminated when each specimen reached its failure. Research findings showed that implementing shorter double angle (83 cm) sections, increased compression strength of steel angle section up to 13 %. Significant deformation occurring only on the flange for both of specimens indicated that implementing double angle is effective to prevent lateral-torsional buckling.

Three-Dimensional Model of Heat and Mass Transfer in Fractured Rocks to Estimate Environmental Conditions Along Heated Drifts

NASA Astrophysics Data System (ADS)

Fedors, R. W.; Painter, S. L.

2004-12-01

Temperature gradients along the thermally-perturbed drifts of the potential high-level waste repository at Yucca Mountain, Nevada, will drive natural convection and associated heat and mass transfer along drifts. A three-dimensional, dual-permeability, thermohydrological model of heat and mass transfer was used to estimate the magnitude of temperature gradients along a drift. Temperature conditions along heated drifts are needed to support estimates of repository-edge cooling and as input to computational fluid dynamics modeling of in-drift axial convection and the cold-trap process. Assumptions associated with abstracted heat transfer models and two-dimensional thermohydrological models weakly coupled to mountain-scale thermal models can readily be tested using the three-dimensional thermohydrological model. Although computationally expensive, the fully coupled three-dimensional thermohydrological model is able to incorporate lateral heat transfer, including host rock processes of conduction, convection in gas phase, advection in liquid phase, and latent-heat transfer. Results from the three-dimensional thermohydrological model showed that weakly coupling three-dimensional thermal and two-dimensional thermohydrological models lead to underestimates of temperatures and underestimates of temperature gradients over large portions of the drift. The representative host rock thermal conductivity needed for abstracted heat transfer models are overestimated using the weakly coupled models. If axial flow patterns over large portions of drifts are not impeded by the strong cross-sectional flow patterns imparted by the heat rising directly off the waste package, condensation from the cold-trap process will not be limited to the extreme ends of each drift. Based on the three-dimensional thermohydrological model, axial temperature gradients occur sooner over a larger portion of the drift, though high gradients nearest the edge of the potential repository are dampened. This abstract is an independent product of CNWRA and does not necessarily reflect the view or regulatory position of the Nuclear Regulatory Commission.

49 CFR 393.68 - Compressed natural gas fuel containers.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Compressed natural gas fuel containers. 393.68... AND ACCESSORIES NECESSARY FOR SAFE OPERATION Fuel Systems § 393.68 Compressed natural gas fuel containers. (a) Applicability. The rules in this section apply to compressed natural gas (CNG) fuel...

46 CFR 197.338 - Compressed gas cylinders.

Code of Federal Regulations, 2010 CFR

2010-10-01

... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.338 Compressed gas cylinders. Each compressed gas cylinder must— (a) Be stored in a ventilated area; (b) Be protected from excessive heat; (c... 46 Shipping 7 2010-10-01 2010-10-01 false Compressed gas cylinders. 197.338 Section 197.338...

49 CFR 393.68 - Compressed natural gas fuel containers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Compressed natural gas fuel containers. 393.68... AND ACCESSORIES NECESSARY FOR SAFE OPERATION Fuel Systems § 393.68 Compressed natural gas fuel containers. (a) Applicability. The rules in this section apply to compressed natural gas (CNG) fuel...

Coherent vorticity extraction in resistive drift-wave turbulence: Comparison of orthogonal wavelets versus proper orthogonal decomposition

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

Futatani, S.; Bos, W.J.T.; Del-Castillo-Negrete, Diego B

2011-01-01

We assess two techniques for extracting coherent vortices out of turbulent flows: the wavelet based Coherent Vorticity Extraction (CVE) and the Proper Orthogonal Decomposition (POD). The former decomposes the flow field into an orthogonal wavelet representation and subsequent thresholding of the coefficients allows one to split the flow into organized coherent vortices with non-Gaussian statistics and an incoherent random part which is structureless. POD is based on the singular value decomposition and decomposes the flow into basis functions which are optimal with respect to the retained energy for the ensemble average. Both techniques are applied to direct numerical simulation datamore » of two-dimensional drift-wave turbulence governed by Hasegawa Wakatani equation, considering two limit cases: the quasi-hydrodynamic and the quasi-adiabatic regimes. The results are compared in terms of compression rate, retained energy, retained enstrophy and retained radial flux, together with the enstrophy spectrum and higher order statistics. (c) 2010 Published by Elsevier Masson SAS on behalf of Academie des sciences.« less

Magnetic Alignment of Pulsed Solenoids Using the Pulsed Wire Method

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

Arbelaez, D.; Madur, A.; Lipton, T.M.

2011-04-01

A unique application of the pulsed-wire measurement method has been implemented for alignment of 2.5 T pulsed solenoid magnets. The magnetic axis measurement has been shown to have a resolution of better than 25 {micro}m. The accuracy of the technique allows for the identification of inherent field errors due to, for example, the winding layer transitions and the current leads. The alignment system is developed for the induction accelerator NDCX-II under construction at LBNL, an upgraded Neutralized Drift Compression experiment for research on warm dense matter and heavy ion fusion. Precise alignment is essential for NDCX-II, since the ion beammore » has a large energy spread associated with the rapid pulse compression such that misalignments lead to corkscrew deformation of the beam and reduced intensity at focus. The ability to align the magnetic axis of the pulsed solenoids to within 100 pm of the induction cell axis has been demonstrated.« less

Removal of ice and marine growth from ship surfaces: A concept

NASA Technical Reports Server (NTRS)

Bauman, A. J.

1975-01-01

Proposed surface is structured from sections of low-melting-point alloy. Sections are separated by network of passages for compressed air. Ice or barnacles are removed by passing electrical current through alloy and bursts of compressed air through passages.

Magnetohydrodynamic modeling of three Van Allen Probes storms in 2012 and 2013

NASA Astrophysics Data System (ADS)

Paral, J.; Hudson, M. K.; Kress, B. T.; Wiltberger, M. J.; Wygant, J. R.; Singer, H. J.

2015-08-01

Coronal mass ejection (CME)-shock compression of the dayside magnetopause has been observed to cause both prompt enhancement of radiation belt electron flux due to inward radial transport of electrons conserving their first adiabatic invariant and prompt losses which at times entirely eliminate the outer zone. Recent numerical studies suggest that enhanced ultra-low frequency (ULF) wave activity is necessary to explain electron losses deeper inside the magnetosphere than magnetopause incursion following CME-shock arrival. A combination of radial transport and magnetopause shadowing can account for losses observed at radial distances into L = 4.5, well within the computed magnetopause location. We compare ULF wave power from the Electric Field and Waves (EFW) electric field instrument on the Van Allen Probes for the 8 October 2013 storm with ULF wave power simulated using the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamic (MHD) magnetospheric simulation code coupled to the Rice Convection Model (RCM). Two other storms with strong magnetopause compression, 8-9 October 2012 and 17-18 March 2013, are also examined. We show that the global MHD model captures the azimuthal magnetosonic impulse propagation speed and amplitude observed by the Van Allen Probes which is responsible for prompt acceleration at MeV energies reported for the 8 October 2013 storm. The simulation also captures the ULF wave power in the azimuthal component of the electric field, responsible for acceleration and radial transport of electrons, at frequencies comparable to the electron drift period. This electric field impulse has been shown to explain observations in related studies (Foster et al., 2015) of electron acceleration and drift phase bunching by the Energetic Particle, Composition, and Thermal Plasma Suite (ECT) instrument on the Van Allen Probes.

Local growth of dust- and ice-mixed aggregates as cometary building blocks in the solar nebula

NASA Astrophysics Data System (ADS)

Lorek, S.; Lacerda, P.; Blum, J.

2018-03-01

Context. Comet formation by gravitational instability requires aggregates that trigger the streaming instability and cluster in pebble-clouds. These aggregates form as mixtures of dust and ice from (sub-)micrometre-sized dust and ice grains via coagulation in the solar nebula. Aim. We investigate the growth of aggregates from (sub-)micrometre-sized dust and ice monomer grains. We are interested in the properties of these aggregates: whether they might trigger the streaming instability, how they compare to pebbles found on comets, and what the implications are for comet formation in collapsing pebble-clouds. Methods: We used Monte Carlo simulations to study the growth of aggregates through coagulation locally in the comet-forming region at 30 au. We used a collision model that can accommodate sticking, bouncing, fragmentation, and porosity of dust- and ice-mixed aggregates. We compared our results to measurements of pebbles on comet 67P/Churyumov-Gerasimenko. Results: We find that aggregate growth becomes limited by radial drift towards the Sun for 1 μm sized monomers and by bouncing collisions for 0.1 μm sized monomers before the aggregates reach a Stokes number that would trigger the streaming instability (Stmin). We argue that in a bouncing-dominated system, aggregates can reach Stmin through compression in bouncing collisions if compression is faster than radial drift. In the comet-forming region ( 30 au), aggregates with Stmin have volume-filling factors of 10-2 and radii of a few millimetres. These sizes are comparable to the sizes of pebbles found on comet 67P/Churyumov-Gerasimenko. The porosity of the aggregates formed in the solar nebula would imply that comets formed in pebble-clouds with masses equivalent to planetesimals of the order of 100 km in diameter.

Measurements and modeling of charge carrier lifetime in compressed xenon

NASA Astrophysics Data System (ADS)

Pudov, A. O.; Abyzov, A. S.; Sokolov, S. A.; Davydov, L. N.; Rybka, A. V.; Kutny, V. E.; Melnikov, S. I.; Kholomyeyev, G. A.; Leonov, S. A.; Turchin, A. A.

2018-06-01

Gamma-spectrometers based on high-pressure xenon gas (HPXe) are proving themselves as a great potential alternative to the spectrometers based on high-purity germanium crystals and scintillators. The working medium for the high-resolution HPXe detectors, that is, xenon gas compressed up to pressure ∼50 bar and sometimes doped with hydrogen, methane or others gases, needs to be of very high purity. The gas purity level can be determined by direct measurements or, alternatively, its usability in gamma-spectrometers can be evaluated indirectly through the charge carrier (electron) lifetime measurements. Different approaches and specific setups have been used for the lifetime determination, most of those methods involve the measurement and analyses of individual pulses from ionizing particles registered in an ionization chamber filled with Xe. In the present paper, we report on the HPXe electron lifetime study carried out by using measurements in a cylindrical ionization chamber and the respective analytical charge transport model. Our results support the possibility of carrier lifetime determination in the cylindrical configuration. In addition, the voltage regimes for the use of the chamber in the spectroscopic mode were determined. The measurements were conducted in a two-electrode configuration for a range of pressure values (5 to 50 bar) for the Xe+0.25%H2 gas mixture of ∼6N purity. It is shown that in gases with relatively high values of the electron drift velocity and the electron lifetime, for example low-density gases, the charge collection time measurements can give significantly underestimated lifetime assessment. On the other hand, for the low drift velocity gases, they give much more accurate results. With the use of the analytical model, the electron lifetime was determined more precisely.

Numerical modelling of edge-driven convection during rift-to-drift transition: application to the Red Sea

NASA Astrophysics Data System (ADS)

Fierro, Elisa; Capitanio, Fabio A.; Schettino, Antonio; Morena Salerno, V.

2017-04-01

We use numerical modeling to investigate the coupling of mantle instabilities and surface tectonics along lithospheric steps developing during rifting. We address whether edge driven convection (EDC) beneath rifted continental margins and shear flow during rift-drift transition can play a role in the observed post-rift compressive tectonic evolution of the divergent continental margins along the Red Sea. We run a series of 2D simulations to examine the relationship between the maximum compression and key geometrical parameters of the step beneath continental margins, such as the step height due to lithosphere thickness variation and the width of the margins, and test the effect of rheology varying temperature- and stress-dependent viscosity in the lithosphere and asthenosphere. The development of instabilities is initially illustrated as a function of these parameters, to show the controls on the lithosphere strain distribution and magnitude. We then address the transient evolution of the instabilities to characterize their duration. In an additional suite of models, we address the development of EDC during plate motions, thus accounting for the mantle shearing due to spreading. Our results show an increase of strain with the step height as well as with the margin width up to 200 km. After this value the influence of ridge margin can be neglected. Strain rates are, then, quantified for a range of laboratory-constrained constitutive laws for mantle and lithosphere forming minerals. These models propose a viable mechanism to explain the post-rift tectonic inversion observed along the Arabian continental margin and the episodic ultra-fast sea floor spreading in the central Red Sea, where the role of EDC has been invoked.

Fast Compressive Tracking.

PubMed

Zhang, Kaihua; Zhang, Lei; Yang, Ming-Hsuan

2014-10-01

It is a challenging task to develop effective and efficient appearance models for robust object tracking due to factors such as pose variation, illumination change, occlusion, and motion blur. Existing online tracking algorithms often update models with samples from observations in recent frames. Despite much success has been demonstrated, numerous issues remain to be addressed. First, while these adaptive appearance models are data-dependent, there does not exist sufficient amount of data for online algorithms to learn at the outset. Second, online tracking algorithms often encounter the drift problems. As a result of self-taught learning, misaligned samples are likely to be added and degrade the appearance models. In this paper, we propose a simple yet effective and efficient tracking algorithm with an appearance model based on features extracted from a multiscale image feature space with data-independent basis. The proposed appearance model employs non-adaptive random projections that preserve the structure of the image feature space of objects. A very sparse measurement matrix is constructed to efficiently extract the features for the appearance model. We compress sample images of the foreground target and the background using the same sparse measurement matrix. The tracking task is formulated as a binary classification via a naive Bayes classifier with online update in the compressed domain. A coarse-to-fine search strategy is adopted to further reduce the computational complexity in the detection procedure. The proposed compressive tracking algorithm runs in real-time and performs favorably against state-of-the-art methods on challenging sequences in terms of efficiency, accuracy and robustness.

Monte Carlo Evaluation of a New Track-Finding Method for the VENUS Muon Detector

NASA Astrophysics Data System (ADS)

Asano, Yuzo; Hatanaka, Makoto; Koseki, Tadashi; Mori, Shigeki; Shirakata, Masashi; Yamamoto, Kazumichi

1989-10-01

A new method of finding a track is devised for the VENUS muon detector composed of eight-cell drift-tube modules, each cell having a rectangular cross section of 5× 7 cm2. The new method, in which fourth-order equations are solved by the Ferarri-Cardano method, is especially powerful for a track having a large incident angle with respect to the line normal to the anode-wire plane of a drift tube, compared to the presently used method in which a track is determined by the intersecting points of an equi-drift-distance circle and the anode-wire plane. Cosmic-ray test data for the forward-backward part muon detector support these simulation results.

Structural characterization of drug-like compounds by ion mobility mass spectrometry: comparison of theoretical and experimentally derived nitrogen collision cross sections.

PubMed

Campuzano, Iain; Bush, Matthew F; Robinson, Carol V; Beaumont, Claire; Richardson, Keith; Kim, Hyungjun; Kim, Hugh I

2012-01-17

We present the use of drug-like molecules as a traveling wave (T-wave) ion mobility (IM) calibration sample set, covering the m/z range of 122.1-609.3, the nitrogen collision cross-section (Ω(N(2))) range of 124.5-254.3 Å(2) and the helium collision cross-section (Ω(He)) range of 63.0-178.8 Å(2). Absolute Ω(N(2)) and Ω(He) values for the drug-like calibrants and two diastereomers were measured using a drift-tube instrument with radio frequency (RF) ion confinement. T-wave drift-times for the protonated diastereomers betamethasone and dexamethasone are reproducibly different. Calibration of these drift-times yields T-wave Ω(N(2)) values of 189.4 and 190.4 Å(2), respectively. These results demonstrate the ability of T-wave IM spectrometry to differentiate diastereomers differing in Ω(N(2)) value by only 1 Å(2), even though the resolution of these IM experiments were ∼40 (Ω/ΔΩ). Demonstrated through density functional theory optimized geometries and ionic electrostatic surface potential analysis, the small but measurable mobility difference between the two diastereomers is mainly due to short-range van der Waals interactions with the neutral buffer gas and not long-range charge-induced dipole interactions. The experimental RF-confining drift-tube and T-wave Ω(N(2)) values were also evaluated using a nitrogen based trajectory method, optimized for T-wave operating temperature and pressures, incorporating additional scaling factors to the Lennard-Jones potentials. Experimental Ω(He) values were also compared to the original and optimized helium based trajectory methods.

41 CFR 50-204.8 - Use of compressed air.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 41 Public Contracts and Property Management 1 2013-07-01 2013-07-01 false Use of compressed air. 50-204.8 Section 50-204.8 Public Contracts and Property Management Other Provisions Relating to... CONTRACTS General Safety and Health Standards § 50-204.8 Use of compressed air. Compressed air shall not be...

41 CFR 50-204.8 - Use of compressed air.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Use of compressed air. 50-204.8 Section 50-204.8 Public Contracts and Property Management Other Provisions Relating to... CONTRACTS General Safety and Health Standards § 50-204.8 Use of compressed air. Compressed air shall not be...

49 CFR 571.303 - Standard No. 303; Fuel system integrity of compressed natural gas vehicles.

Code of Federal Regulations, 2010 CFR

2010-10-01

... compressed natural gas vehicles. 571.303 Section 571.303 Transportation Other Regulations Relating to... system integrity of compressed natural gas vehicles. S1. Scope. This standard specifies requirements for the integrity of motor vehicle fuel systems using compressed natural gas (CNG), including the CNG fuel...

Pretest 3-D finite element modeling of the wedge pillar portion of the WIPP (Waste Isolation Pilot Plant) Geomechanical Evaluation (Room G) in situ experiment. [Waste Isolation Pilot Plant

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

Preece, D.S.

Pretest 3-D finite element calculations have been performed on the wedge pillar portion of the WIPP Geomechanical Evaluation Experiment. The wedge pillar separates two drifts that intersect at an angle of 7.5/sup 0/. Purpose of the experiment is to provide data on the creep behavior of the wedge and progressive failure at the tip. The first set of calculations utilized a symmetry plane on the center-line of the wedge which allowed treatment of the entire configuration by modeling half of the geometry. Two 3-D calculations in this first set were performed with different drift widths to study the influence ofmore » drift size on closure and maximum stress. A cross-section perpendicular to the wedge was also analyzed with 2-D finite element models and the results compared to the 3-D results. In another set of 3-D calculations both drifts were modeled but with less distance between the drifts and the outer boundaries. Results of these calculations are compared with results from the other calculations to better understand the influence of boundary conditions.« less

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

Simon, Anne-Laure; Choi, Chang Min; Clavier, Christian

This manuscript describes a new experimental setup that allows to perform tandem ion mobility spectrometry (IMS) measurements and which is coupled to a high resolution time-of-flight mass spectrometer. It consists of two 79 cm long drift tubes connected by a dual ion funnel assembly. The setup was built to permit laser irradiation of the ions in the transfer region between the two drift tubes. This geometry allows selecting ions according to their ion mobility in the first drift tube, to irradiate selected ions, and examine the ion mobility of the product ions in the second drift tube. Activation by collisionmore » is possible in the same region (between the two tubes) and between the second tube and the time-of-flight. IMS-IMS experiments on Ubiquitin are reported. We selected a given isomer of charge state +7 and explored its structural rearrangement following collisional activation between the two drift tubes. An example of IMS-laser-IMS experiment is reported on eosin Y, where laser irradiation was used to produce radical ions by electron photodetachment starting from doubly deprotonated species. This allowed measuring the collision cross section of the radical photo-product, which cannot be directly produced with an electrospray source.« less

Tandem ion mobility spectrometry coupled to laser excitation

NASA Astrophysics Data System (ADS)

Simon, Anne-Laure; Chirot, Fabien; Choi, Chang Min; Clavier, Christian; Barbaire, Marc; Maurelli, Jacques; Dagany, Xavier; MacAleese, Luke; Dugourd, Philippe

2015-09-01

This manuscript describes a new experimental setup that allows to perform tandem ion mobility spectrometry (IMS) measurements and which is coupled to a high resolution time-of-flight mass spectrometer. It consists of two 79 cm long drift tubes connected by a dual ion funnel assembly. The setup was built to permit laser irradiation of the ions in the transfer region between the two drift tubes. This geometry allows selecting ions according to their ion mobility in the first drift tube, to irradiate selected ions, and examine the ion mobility of the product ions in the second drift tube. Activation by collision is possible in the same region (between the two tubes) and between the second tube and the time-of-flight. IMS-IMS experiments on Ubiquitin are reported. We selected a given isomer of charge state +7 and explored its structural rearrangement following collisional activation between the two drift tubes. An example of IMS-laser-IMS experiment is reported on eosin Y, where laser irradiation was used to produce radical ions by electron photodetachment starting from doubly deprotonated species. This allowed measuring the collision cross section of the radical photo-product, which cannot be directly produced with an electrospray source.

40 CFR 161.108 - Relationship of Pesticide Assessment Guidelines to data requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Environmental Fate PB83-153973 161.290 O Residue Chemistry PB83-153961 161.240 R Spray Drift Evaluation PB84... Guidelines to data requirements. 161.108 Section 161.108 Protection of Environment ENVIRONMENTAL PROTECTION...: Subdivision Title NTIS order no. Corresponding section(s) in this part D Product Chemistry PB83-153890 161.150...

49 CFR 173.314 - Compressed gases in tank cars and multi-unit tank cars.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Compressed gases in tank cars and multi-unit tank cars. 173.314 Section 173.314 Transportation Other Regulations Relating to Transportation PIPELINE AND... Compressed gases in tank cars and multi-unit tank cars. (a) Definitions. For definitions of compressed gases...

49 CFR 173.314 - Compressed gases in tank cars and multi-unit tank cars.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Compressed gases in tank cars and multi-unit tank cars. 173.314 Section 173.314 Transportation Other Regulations Relating to Transportation PIPELINE AND... Compressed gases in tank cars and multi-unit tank cars. (a) Definitions. For definitions of compressed gases...

41 CFR 50-204.8 - Use of compressed air.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Use of compressed air. 50-204.8 Section 50-204.8 Public Contracts and Property Management Other Provisions Relating to Public... General Safety and Health Standards § 50-204.8 Use of compressed air. Compressed air shall not be used for...

The Pianosa Contourite Depositional System (Northern Tyrrhenian Sea): drift morphology and Plio-Quaternary stratigraphic evolution

NASA Astrophysics Data System (ADS)

Miramontes Garcia, Elda; Cattaneo, Antonio; Jouet, Gwenael; Thereau, Estelle; Thomas, Yannick; Rovere, Marzia; Cauquil, Eric; Trincardi, Fabio

2016-04-01

The Pianosa Contourite Depositional System (CDS) is located in the Corsica Trough (Northern Tyrrhenian Sea), a confined basin dominated by mass transport and contour currents in the eastern flank and by turbidity currents in the western flank. The morphologic and stratigraphic characterisation of the Pianosa CDS is based on multibeam bathymetry, seismic reflection data (multi-channel high resolution mini GI gun, single-channel sparker and CHIRP), sediment cores and ADCP data. The Pianosa CDS is located at shallow to intermediate water depths (170 to 850 m water depth) and is formed under the influence of the Levantine Intermediate Water (LIW). It is 120 km long, has a maximum width of 10 km and is composed of different types of muddy sediment drifts: plastered drift, separated mounded drift, sigmoid drift and multicrested drift. The reduced tectonic activity in the Corsica Trough since the early Pliocene permits to recover a sedimentary record of the contourite depositional system that is only influenced by climate fluctuations. Contourites started to develop in the Middle-Late Pliocene, but their growth was enhanced since the Middle Pleistocene Transition (0.7-0.9 Ma). Although the general circulation of the LIW, flowing northwards in the Corsica Trough, remained active all along the history of the system, contourite drift formation changed, controlled by sediment influx and bottom current velocity. During periods of sea level fall, fast bottom currents often eroded the drift crest in the middle and upper slope. At that time the proximity of the coast to the shelf edge favoured the formation of bioclastic sand deposits winnowed by bottom currents. Higher sediment accumulation of mud in the drifts occurred during periods of fast bottom currents and high sediment availability (i.e. high activity of turbidity currents), coincident with periods of sea level low-stands. Condensed sections were formed during sea level high-stands, when bottom currents were more sluggish and the turbidite system was disconnected, resulting in a lower sediment influx.

The NDCX-II engineering design

NASA Astrophysics Data System (ADS)

Waldron, W. L.; Abraham, W. J.; Arbelaez, D.; Friedman, A.; Galvin, J. E.; Gilson, E. P.; Greenway, W. G.; Grote, D. P.; Jung, J.-Y.; Kwan, J. W.; Leitner, M.; Lidia, S. M.; Lipton, T. M.; Reginato, L. L.; Regis, M. J.; Roy, P. K.; Sharp, W. M.; Stettler, M. W.; Takakuwa, J. H.; Volmering, J.; Vytla, V. K.

2014-01-01

The Neutralized Drift Compression Experiment (NDCX-II) is a user facility located at Lawrence Berkeley National Laboratory which is uniquely designed for ion-beam-driven high energy density laboratory physics and heavy ion fusion research. Construction was completed in March 2012 and the facility is now in the commissioning phase. A significant amount of engineering was carried out in order to meet the performance parameters required for a wide range of target heating experiments while making the most cost-effective use of high-value hardware available from a decommissioned high current electron induction accelerator. The technical challenges and design of this new ion induction accelerator facility are described.

Techniques in processing multi-frequency multi-polarization spaceborne SAR data

NASA Technical Reports Server (NTRS)

Curlander, John C.; Chang, C. Y.

1991-01-01

This paper presents the algorithm design of the SIR-C ground data processor, with emphasis on the unique elements involved in the production of registered multifrequency polarimetric data products. A quick-look processing algorithm used for generation of low-resolution browse image products and estimation of echo signal parameters is also presented. Specifically the discussion covers: (1) azimuth reference function generation to produce registered polarimetric imagery; (2) geometric rectification to accommondate cross-track and along-track Doppler drifts; (3) multilook filtering designed to generate output imagery with a uniform resolution; and (4) efficient coding to compress the polarimetric image data for distribution.

Effective Cross Section of Cold Formed Steel Column Under Axial Compression

NASA Astrophysics Data System (ADS)

Manikandan, P.; Pradeep, T.

2018-06-01

The compressive resistance of cold-formed steel (CFS) section may be governed by local, distortional or overall buckling and any apparent interaction between these modes. A new inventive stiffened CFS section is elected in this study, selected cross sections geometries and lengths are chosen such that all the types of buckling modes are met with. Buckling plot is plotted using linear elastic buckling analysis software (CUFSM). Using the test results obtained in the literature, the developed finite element model is calibrated and furthers a total of 126 parametric study is conducted such as a consequence of dimensions and the length of the cross section, thickness and yield stress. The FEA included relevant material and geometric imperfections. All the columns are analyzed under pin end conditions with axial compression. The analysis results demonstrate that the DSM equations generally assess the strength of stiffened section conservatively. Modifications to the DSM equations are recommended to evaluate the strength of stiffened section more precisely.

46 CFR 56.30-25 - Flared, flareless, and compression fittings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Flared, flareless, and compression fittings. 56.30-25 Section 56.30-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING... devices, and shape memory alloys. Fittings to which this section applies must be designed, constructed...

Behaviour of thin-walled cold-formed steel members in eccentric compression

NASA Astrophysics Data System (ADS)

Ungureanu, Viorel; Kotełko, Maria; Borkowski, Łukasz; Grudziecki, Jan

2018-01-01

Thin-walled cold-formed steel structures are usually made of members of class 4 cross-sections. Since these sections are prematurely prone to local or distortional buckling and due to the fact they do not have a real post-elastic capacity, the failure at ultimate stage of those members, either in compression or bending, always occurs by forming a local plastic mechanism. The present paper investigates the evolution of the plastic mechanisms and the possibility to use them to characterise the ultimate strength of short thin-walled cold-formed steel members subjected to eccentric compression about minor axis, particularly for members with lipped channel cross-section. Five different types of plastic mechanisms for members in compression with different eccentricities are identified and examined on the basis of FE numerical simulations. Preliminary results of experimental validation of numerical results are presented. The research is based on previous studies and some new investigations of the authors.

Rotary vane type IC engine with built-in scavenging air blower

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

Chang, V.

This patent describes a rotary internal combustion engine. This engine consists of: a housing assembly including three sections and having a single common power shaft, the three sections being integrally connected together and operatively connected together into a unitary self-contained engine, air and fuel mixture intake conduit means communicatively connected to a first of the three sections, means in the first section to perform admission and compression of the air and fuel mixture admitted from the conduit means, means to convey the compressed air and fuel mixture to a second of the three sections. A single internal partition wall meansmore » between the first and second sections, and the air and fuel mixture conveys means consisting of a port formed in the partition wall means. In the second section the compressed air is ignited with a fuel mixture and to permit expansion of the ignited air and fuel mixture to thereby furnish power strokes to the power shaft. In the second section for exhausting the gaseous products of combustion, air blower in the third of the three sections driven by the power shaft.« less

Using spatial, seasonal, and diel drift patterns of larval Lost River suckers Deltistes luxatus (Cypriniformes: Catostomidae) and shortnose suckers Chasmistes brevirostris (Cypriniformes: Catostomidae) to help identify a site for a water withdrawal structure on the Williamson River, Oregon

USGS Publications Warehouse

Ellsworth, Craig M.; Tyler, Torrey J.; VanderKooi, Scott P.

2010-01-01

A small irrigation diversion dam near Chiloquin, Oregon, was removed and replaced with a pump station to improve fish passage for Lost River suckers (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) entering the Sprague River on their spawning migrations. During the developmental phase of the pump station, a need was identified to better understand the larval drift characteristics of these endangered catostomids in order to reduce entrainment into the irrigation system. The spatial, seasonal, and diel distribution of drifting larvae was measured during the 2004 spawning season at two proposed sites on the Williamson River where the pump station could be located. Larval drift for both species coincided with the irrigation season making them subject to entrainment into the irrigation system. Drift occurred almost exclusively at night with larvae entering the drift at sunset and exiting the drift at sunrise. Nighttime larval densities were concentrated near the surface and at midchannel at both sites. Densities were generally greater on the side of mid-channel with greater flow. During early morning sampling we detected a general shift in larval drift from surface to subsurface drift. We also observed an increase in larval densities towards the shore opposite from the proposed pump station at the upper site whereas larval densities remained high at midchannel at the lower site. During daytime sampling, the few larvae that were collected were distributed throughout the water column at both pump sites. This study found that larvae drifting during all time periods were generally distributed further across the cross section, deeper in the water column, and closer to where the proposed water withdrawal structure would be built at the downstream site when compared to the upstream site. Recommendations were provided to locate the withdrawal facility at the upstream site and operate it in a manner such that larval entrainment would likely be minimized.

Advanced End-to-end Simulation for On-board Processing (AESOP)

NASA Technical Reports Server (NTRS)

Mazer, Alan S.

1994-01-01

Developers of data compression algorithms typically use their own software together with commercial packages to implement, evaluate and demonstrate their work. While convenient for an individual developer, this approach makes it difficult to build on or use another's work without intimate knowledge of each component. When several people or groups work on different parts of the same problem, the larger view can be lost. What's needed is a simple piece of software to stand in the gap and link together the efforts of different people, enabling them to build on each other's work, and providing a base for engineers and scientists to evaluate the parts as a cohesive whole and make design decisions. AESOP (Advanced End-to-end Simulation for On-board Processing) attempts to meet this need by providing a graphical interface to a developer-selected set of algorithms, interfacing with compiled code and standalone programs, as well as procedures written in the IDL and PV-Wave command languages. As a proof of concept, AESOP is outfitted with several data compression algorithms integrating previous work on different processors (AT&T DSP32C, TI TMS320C30, SPARC). The user can specify at run-time the processor on which individual parts of the compression should run. Compressed data is then fed through simulated transmission and uncompression to evaluate the effects of compression parameters, noise and error correction algorithms. The following sections describe AESOP in detail. Section 2 describes fundamental goals for usability. Section 3 describes the implementation. Sections 4 through 5 describe how to add new functionality to the system and present the existing data compression algorithms. Sections 6 and 7 discuss portability and future work.

46 CFR 147.60 - Compressed gases.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Compressed gases. 147.60 Section 147.60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.60 Compressed gases. (a) Cylinder requirements...

46 CFR 147.60 - Compressed gases.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Compressed gases. 147.60 Section 147.60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.60 Compressed gases. (a) Cylinder requirements...

46 CFR 147.60 - Compressed gases.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Compressed gases. 147.60 Section 147.60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.60 Compressed gases. (a) Cylinder requirements...

46 CFR 147.60 - Compressed gases.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Compressed gases. 147.60 Section 147.60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.60 Compressed gases. (a) Cylinder requirements...

Prefraction displacement and intrafraction drift of the prostate due to perineal ultrasound probe pressure.

PubMed

Li, Minglun; Hegemann, Nina-Sophie; Manapov, Farkhad; Kolberg, Anne; Thum, Patrick Dominik; Ganswindt, Ute; Belka, Claus; Ballhausen, Hendrik

2017-06-01

In image-guided EBRT of the prostate, transperineal ultrasound (US) probes exert pressure on the perineum both during planning and treatment. Through tissue deformation and relaxation, this causes target and risk organ displacement and drift. In this study, prefraction shift and intrafraction drift of the prostate are quantified during robotic transperineal 4DUS. The position of the prostate was recorded for different positions of the probe before treatment in 10 patients (16 series of measurements). During treatment (15 patients, 273 fractions), intrafraction motion of the prostate was tracked (total of 27 h and 24 min) with the transperineal probe in place. Per 1 mm shift of the US probe in the cranial direction, a displacement of the prostate by 0.42 ± 0.09 mm in the cranial direction was detected. The relationship was found to be linear (R² = 0.97) and highly significant (p < 0.0001). After initial contact of the probe and the perineum (no pressure), a shift of the probe of about 5-10 mm was typically necessary to achieve good image quality, corresponding to a shift of the prostate of about 2-4 mm in the cranial direction. Tissue compression and prostate displacement were well visible. During treatment, the prostate drifted at an average rate of 0.075 mm/min in the cranial direction (p = 0.0014). The pressure applied by a perineal US probe has a quantitatively similar impact on prostate displacement as transabdominal pressure. Shifts are predominantly in the cranial direction (typically 2-4 mm) with some component in the anterior direction (typically <1 mm). Slight probe pressure can improve image quality, but excessive probe pressure can distort the surrounding anatomy and potentially move risk organs closer to the high-dose area.

Changing patterns in coastal cutthroat trout (Oncorhynchus clarki clarki) diet and prey in a gradient of deciduous canopies

USGS Publications Warehouse

Romero, N.; Gresswell, R.E.; Li, J.L.

2005-01-01

We examined the influence of riparian vegetation patterns on coastal cutthroat trout Oncorhynchus clarki clarki diet and prey from the summer of 2001 through the spring of 2002. Benthic and drifting invertebrates, allochthonous prey, and fish diet were collected from deciduous, conifer, and mixed sections of three Oregon coastal watersheds. The nine sites were best characterized as a continuum of deciduous cover, and shrub cover and proportion of deciduous canopy were positively correlated (r = 0.74). Most sources of prey (benthic invertebrate biomass, allochthonous invertebrate inputs, aquatic and total invertebrate drift) and aquatic prey ingested by coastal cutthroat trout were greater where shrub cover was more abundant. Only aquatic drift, total invertebrate drift, and allochthonous invertebrates were positively correlated with deciduous vegetation. Compared with coniferous sites, allochthonous invertebrates under deciduous and mixed canopies were almost 30% more abundant. Stream discharge likely influenced seasonal fluxes of aquatic invertebrate biomass in the benthos and drift. Aquatic insects dominated gut contents during this study; however, terrestrial prey were most common in the diet during the summer and fall. In the Pacific northwest, systematic removal of deciduous riparian vegetation to promote conifers may have unintended consequences on food resources of coastal cutthroat trout and aquatic food web interactions. ?? 2005 NRC.

In-Drift Microbial Communities

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

D. Jolley

2000-11-09

As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999).more » This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses.« less

Finite Element Analysis of Increasing Column Section and CFRP Reinforcement Method under Different Axial Compression Ratio

NASA Astrophysics Data System (ADS)

Jinghai, Zhou; Tianbei, Kang; Fengchi, Wang; Xindong, Wang

2017-11-01

Eight less stirrups in the core area frame joints are simulated by ABAQUS finite element numerical software. The composite reinforcement method is strengthened with carbon fiber and increasing column section, the axial compression ratio of reinforced specimens is 0.3, 0.45 and 0.6 respectively. The results of the load-displacement curve, ductility and stiffness are analyzed, and it is found that the different axial compression ratio has great influence on the bearing capacity of increasing column section strengthening method, and has little influence on carbon fiber reinforcement method. The different strengthening schemes improve the ultimate bearing capacity and ductility of frame joints in a certain extent, composite reinforcement joints strengthening method to improve the most significant, followed by increasing column section, reinforcement method of carbon fiber reinforced joints to increase the minimum.

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

Bolotnikov, A. E., E-mail: bolotnik@bnl.gov; Camarda, G. S.; Cui, Y.

We investigated the feasibility of long-drift-time CdZnTe (CZT) gamma-ray detectors, fabricated from CZT material produced by Redlen Technologies. CZT crystals with cross-section areas of 5 × 5 mm{sup 2} and 6 × 6 mm{sup 2} and thicknesses of 20-, 30-, 40-, and 50-mm were configured as 3D position-sensitive drift detectors and were read out using a front-end ASIC. By correcting the electron charge losses caused by defects in the crystals, we demonstrated high performance for relatively thick detectors fabricated from unselected CZT material.

Alpha particle confinement in tandem mirrors

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

Devoto, R.S.; Ohnishi, M.; Kerns, J.

1980-10-10

Mechanisms leading to loss of alpha particles from non-axisymmetric tandem mirrors are considered. Stochastic diffusion due to bounce-drift resonances, which can cause rapid radial losses of high-energy alpha particles, can be suppressed by imposing a 20% rise in axisymmetric fields before the quadrupole transition sections. Alpha particles should then be well-confined until thermal energies when they enter the resonant plateau require. A fast code for computation of drift behavior in reactors is described. Sample calculations are presented for resonant particles in a proposed coil set for the Tandem Mirror Next Step.

46 CFR 188.10-41 - Liquefied compressed gas.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Liquefied compressed gas. 188.10-41 Section 188.10-41 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-41 Liquefied compressed gas. This term means...

46 CFR 188.10-41 - Liquefied compressed gas.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Liquefied compressed gas. 188.10-41 Section 188.10-41 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-41 Liquefied compressed gas. This term means...

46 CFR 188.10-41 - Liquefied compressed gas.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Liquefied compressed gas. 188.10-41 Section 188.10-41 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-41 Liquefied compressed gas. This term means...

46 CFR 188.10-41 - Liquefied compressed gas.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Liquefied compressed gas. 188.10-41 Section 188.10-41 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-41 Liquefied compressed gas. This term means...

46 CFR 188.10-41 - Liquefied compressed gas.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Liquefied compressed gas. 188.10-41 Section 188.10-41 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS GENERAL PROVISIONS Definition of Terms Used in This Subchapter § 188.10-41 Liquefied compressed gas. This term means...

30 CFR 75.1106-3 - Storage of liquefied and nonliquefied compressed gas cylinders; requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... or soldering, and exposure to flammable liquids. (b) Liquefied and nonliquefied compressed gas... compressed gas cylinders; requirements. 75.1106-3 Section 75.1106-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES...

Boltzmann Calculations of Electron Transport in CF4 and CF_4/Ar

NASA Astrophysics Data System (ADS)

Wang, Yicheng; van Brunt, R. J.

1996-10-01

A new set of electron collisional cross sections(L. G. Christophorou, J. K. Olthoff, and M. V. V. S. Rao, J. Phys. Chem. Ref. Data, submitted (May 1996)) for CF4 has been proposed, based primarily upon available experimental measurements. In this paper we present the results of calculations of the drift velocity, ionization coefficient, and attachment coefficient for electrons in CF4 based upon the new cross section set, using a two-term Boltzmann calculation. Comparison of results with experimental determinations of the transport parameters, such as drift velocity, are presented, along with comparison of results obtained using two previously pubished(M. Hyashi, in Swarm Studies and Elastic Electron-Molecule Collisions) (1987); and Y. Nakamura in Gaseous Electronics and Their Applications (1991) electron impact cross section sets for CF_4. Additions and adjustments to the cross section sets required for the model to achieve consitency with transport data are discussed. - Research sponsored in part by the U.S. Air Force Wright Laboratory under contract F33615-96-C-2600 with the University of Tennessee. Also, Department of Physics, The University of Tennessee, Knoxville, TN.

Effects of repeated insecticide pulses on macroinvertebrate drift in indoor stream mesocosms.

PubMed

Berghahn, Rüdiger; Mohr, Silvia; Hübner, Verena; Schmiediche, Ronny; Schmiedling, Ina; Svetich-Will, Erkki; Schmidt, Ralf

2012-10-15

Pesticide contaminations via run-off or spray drift have been reported to result in the mass drift of macroinvertebrates as well as causing structural and functional changes of the corresponding stream sections. However, pesticide pulses in the field are associated with sudden increases in flow velocity, water turbidity, and changes in water temperature, which can also induce drift. Only through replicated community testing under highly controlled conditions can these effects be disentangled. In a stream mesocosm study, 12-h pulses of 12 μg/L imidacloprid were set three times at weekly intervals and are considered a "pulse series". Two pulse series of this neonicotinoid insecticide were run in both spring and summer with 4 treatment and 4 control stream mesocosms used in each pulse series. Prior to the start of the mesocosm experiment, both pulse concentration and duration had been screened for drift responses in larval Baetidae, Chironomidae and adult Gammarus roeseli in laboratory experiments. In the subsequent mesocosm study, each pulse caused a pronounced increase in the drift of insect larvae and gammarids. The drift response was taxon-specific, which was related to preferred habitat and exposure to other stressors like current velocity, in addition to imidacloprid sensitivity. Activity measurements employing a Multispecies Freshwater Biomonitor(®) revealed that in Baetis sp. the diurnal activity pattern became more pronounced even 12h after the pulse though with slightly decreased mean physical activity. Adult G. roeseli showed a drastic pulse by pulse decrease in physical activity which after the 3rd pulse lasted longer than 24h. In conclusion, drift is a sensitive, ecologically relevant endpoint and should be regarded when a specific risk assessment for lotic surface waters is done, e.g. in the context of a spatially explicit risk assessment. Copyright © 2012 Elsevier B.V. All rights reserved.

Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies

NASA Astrophysics Data System (ADS)

Ji, Q.; Seidl, P. A.; Waldron, W. L.; Takakuwa, J. H.; Friedman, A.; Grote, D. P.; Persaud, A.; Barnard, J. J.; Schenkel, T.

2016-02-01

The neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ˜1 eV using intense, short pulses (˜1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He+ ions leads to more uniform energy deposition of the target material than Li+ ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li+ ions from a hot plate type ion source. He+ beam pulses as high as 200 mA at the peak and 4 μs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. The accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.

Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies.

PubMed

Ji, Q; Seidl, P A; Waldron, W L; Takakuwa, J H; Friedman, A; Grote, D P; Persaud, A; Barnard, J J; Schenkel, T

2016-02-01

The neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ∼1 eV using intense, short pulses (∼1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He(+) ions leads to more uniform energy deposition of the target material than Li(+) ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li(+) ions from a hot plate type ion source. He(+) beam pulses as high as 200 mA at the peak and 4 μs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. The accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.

Development and testing of a pulsed helium ion source for probing materials and warm dense matter studies

DOE PAGES

Ji, Q.; Seidl, P. A.; Waldron, W. L.; ...

2015-11-12

In this paper, the neutralized drift compression experiment was designed and commissioned as a pulsed, linear induction accelerator to drive thin targets to warm dense matter (WDM) states with peak temperatures of ~1 eV using intense, short pulses (~1 ns) of 1.2 MeV lithium ions. At that kinetic energy, heating a thin target foil near the Bragg peak energy using He + ions leads to more uniform energy deposition of the target material than Li + ions. Experiments show that a higher current density of helium ions can be delivered from a plasma source compared to Li + ions frommore » a hot plate type ion source. He + beam pulses as high as 200 mA at the peak and 4 μs long were measured from a multi-aperture 7-cm-diameter emission area. Within ±5% variation, the uniform beam area is approximately 6 cm across. Finally, the accelerated and compressed pulsed ion beams can be used for materials studies and isochoric heating of target materials for high energy density physics experiments and WDM studies.« less

Effects of drift gas on collision cross sections of a protein standard in linear drift tube and traveling wave ion mobility mass spectrometry.

PubMed

Jurneczko, Ewa; Kalapothakis, Jason; Campuzano, Iain D G; Morris, Michael; Barran, Perdita E

2012-10-16

There has been a significant increase in the use of ion mobility mass spectrometry (IM-MS) to investigate conformations of proteins and protein complexes following electrospray ionization. Investigations which employ traveling wave ion mobility mass spectrometry (TW IM-MS) instrumentation rely on the use of calibrants to convert the arrival times of ions to collision cross sections (CCS) providing "hard numbers" of use to structural biology. It is common to use nitrogen as the buffer gas in TW IM-MS instruments and to calibrate by extrapolating from CCS measured in helium via drift tube (DT) IM-MS. In this work, both DT and TW IM-MS instruments are used to investigate the effects of different drift gases (helium, neon, nitrogen, and argon) on the transport of multiply charged ions of the protein myoglobin, frequently used as a standard in TW IM-MS studies. Irrespective of the drift gas used, recorded mass spectra are found to be highly similar. In contrast, the recorded arrival time distributions and the derived CCS differ greatly. At low charge states (7 ≤ z ≤ 11) where the protein is compact, the CCS scale with the polarizability of the gas; this is also the case for higher charge states (12 ≤ z ≤ 22) where the protein is more unfolded for the heavy gases (neon, argon, and nitrogen) but not the case for helium. This is here interpreted as a different conformational landscape being sampled by the lighter gas and potentially attributable to increased field heating by helium. Under nanoelectrospray ionization (nESI) conditions, where myoglobin is sprayed from an aqueous solution buffered to pH 6.8 with 20 mM ammonium acetate, in the DT IM-MS instrument, each buffer gas can yield a different arrival time distribution (ATD) for any given charge state.

Derivation of the threshold condition for the ion temperature gradient mode with an inverted density profile from a simple physics picture

NASA Astrophysics Data System (ADS)

Jhang, Hogun

2018-05-01

We show that the threshold condition for the toroidal ion temperature gradient (ITG) mode with an inverted density profile can be derived from a simple physics argument. The key in this picture is that the density inversion reduces the ion compression due to the ITG mode and the electron drift motion mitigates the poloidal potential build-up. This condition reproduces the same result that has been reported from a linear gyrokinetic calculation [T. S. Hahm and W. M. Tang, Phys. Fluids B 1, 1185 (1989)]. The destabilizing role of trapped electrons in toroidal geometry is easily captured in this picture.

46 CFR 194.15-15 - Chemicals other than compressed gases.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Chemicals other than compressed gases. 194.15-15 Section... Scientific Laboratory § 194.15-15 Chemicals other than compressed gases. Chemicals, including those listed in 49 CFR part 172, may be stored in small working quantities in the chemical laboratory. [CGD 86-033...

46 CFR 194.15-15 - Chemicals other than compressed gases.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 7 2012-10-01 2012-10-01 false Chemicals other than compressed gases. 194.15-15 Section... Scientific Laboratory § 194.15-15 Chemicals other than compressed gases. Chemicals, including those listed in 49 CFR part 172, may be stored in small working quantities in the chemical laboratory. [CGD 86-033...

46 CFR 194.15-15 - Chemicals other than compressed gases.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 7 2014-10-01 2014-10-01 false Chemicals other than compressed gases. 194.15-15 Section... Scientific Laboratory § 194.15-15 Chemicals other than compressed gases. Chemicals, including those listed in 49 CFR part 172, may be stored in small working quantities in the chemical laboratory. [CGD 86-033...

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2014 CFR

2014-07-01

... receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 56.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure vessels... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 56.13015 Section 56.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2012 CFR

2012-07-01

... receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2013 CFR

2013-07-01

... receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57.13015 Mineral Resources MINE SAFETY AND HEALTH...

30 CFR 57.13015 - Inspection of compressed-air receivers and other unfired pressure vessels.

Code of Federal Regulations, 2011 CFR

2011-07-01

... receivers and other unfired pressure vessels. (a) Compressed-air receivers and other unfired pressure... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Inspection of compressed-air receivers and other unfired pressure vessels. 57.13015 Section 57.13015 Mineral Resources MINE SAFETY AND HEALTH...

Short wavelength limits of current shot noise suppression

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

Nause, Ariel, E-mail: arielnau@post.tau.ac.il; Dyunin, Egor; Gover, Avraham

Shot noise in electron beam was assumed to be one of the features beyond control of accelerator physics. Current results attained in experiments at Accelerator Test Facility in Brookhaven and Linac Coherent Light Source in Stanford suggest that the control of the shot noise in electron beam (and therefore of spontaneous radiation and Self Amplified Spontaneous Emission of Free Electron Lasers) is feasible at least in the visible range of the spectrum. Here, we present a general linear formulation for collective micro-dynamics of e-beam noise and its control. Specifically, we compare two schemes for current noise suppression: a quarter plasmamore » wavelength drift section and a combined drift/dispersive (transverse magnetic field) section. We examine and compare their limits of applicability at short wavelengths via considerations of electron phase-spread and the related Landau damping effect.« less

Spatial Control of Photoacid Diffusion in Chemically Amplified Resist (CAR) via External Electric Field.

PubMed

Kim, Jinok; Yoo, Gwangwe; Park, Jin; Park, Jin-Hong

2018-09-01

We investigated the effect of an electric field-based post exposure bake (EF-PEB) process on photoacid diffusion and pattern formation. To investigate the control of photoacid diffusion experimentally, the EF-PEB processes was performed at various temperatures. Cross sectional images of various EF-PEB processed samples were obtained by scanning electron microscopy (SEM) after ion beam milling. In addition, we conducted a numerical analysis of photoacid distribution and diffusion with following Fick's second law and compared the experimental results with our theoretical model. The drift distance was theoretically predicted by multiplying drift velocity and EF-PEB time, and the experimental values were obtained by finding the difference in pattern depths of PEB/EFPEB samples. Finally, an EF-PEB temperature of 85 °C was confirmed as the optimum condition to maximize photoacid drift distance using the electric field.

Fishbone Oscillations in the Experimental Advanced Superconductivity Tokamak

NASA Astrophysics Data System (ADS)

Xu, Li-Qing; Hu, Li-Qun; Yuan, Yi; Li, Ying-Ying; Zhong, Guo-Qiang; Liu, Hai-Qing; Chen, Kai-Yun; Shi, Tong-Hui; Duan, Yan-Min

2018-03-01

A fishbone oscillation was observed in the neutral beam injection plasma at Experimental Advanced Superconductivity Tokamak (EAST). This m = 1/n = 1 ( m, n: poloidal, toroidal mode numbers, respectively) typical internal kink mode travels in the ion-diamagnetism direction in the poloidal section with a rotation speed close to the ion diamagnetic drift frequency. A high thermal plasma beta and high amounts of energetic ions are necessary for the mode to develop. Fishbone oscillations can expel heavy impurities in the core, which favors sustaining a high-performance plasma. The born frequency of the fishbone oscillation is the ion diamagnetic drift frequency and the chirping down of the frequency during the initial growth phase is the result of a drop in iondiamagnetic drift frequency. The excitation energy is thought to be due to the thermal plasma pressure gradient; however, the development of a fishbone oscillation is related to energetic ions.

Study on the influence of supplying compressed air channels and evicting channels on pneumatical oscillation systems for vibromooshing

NASA Astrophysics Data System (ADS)

Glăvan, D. O.; Radu, I.; Babanatsas, T.; Babanatis Merce, R. M.; Kiss, I.; Gaspar, M. C.

2018-01-01

The paper presents a pneumatic system with two oscillating masses. The system is composed of a cylinder (framework) with mass m1, which has a piston with mass m2 inside. The cylinder (framework system) has one supplying channel for compressed air and one evicting channel for each work chamber (left and right of the piston). Functionality of the piston position comparatively with the cylinder (framework) is possible through the supplying or evicting of compressed air. The variable force that keeps the movement depends on variation of the pressure that is changing depending on the piston position according to the cylinder (framework) and to the section form that is supplying and evicting channels with compressed air. The paper presents the physical model/pattern, the mathematical model/pattern (differential equations) and numerical solution of the differential equations in hypothesis with the section form of supplying and evicting channels with compressed air is rectangular (variation linear) or circular (variation nonlinear).

26 CFR 48.4041-21 - Compressed natural gas (CNG).

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Compressed natural gas (CNG). 48.4041-21 Section... natural gas (CNG). (a) Delivery of CNG into the fuel supply tank of a motor vehicle or motorboat—(1) Imposition of tax. Tax is imposed on the delivery of compressed natural gas (CNG) into the fuel supply tank...

Improving signal to noise in labeled biological specimens using energy-filtered TEM of sections with a drift correction strategy and a direct detection device.

PubMed

Ramachandra, Ranjan; Bouwer, James C; Mackey, Mason R; Bushong, Eric; Peltier, Steven T; Xuong, Nguyen-Huu; Ellisman, Mark H

2014-06-01

Energy filtered transmission electron microscopy techniques are regularly used to build elemental maps of spatially distributed nanoparticles in materials and biological specimens. When working with thick biological sections, electron energy loss spectroscopy techniques involving core-loss electrons often require exposures exceeding several minutes to provide sufficient signal to noise. Image quality with these long exposures is often compromised by specimen drift, which results in blurring and reduced resolution. To mitigate drift artifacts, a series of short exposure images can be acquired, aligned, and merged to form a single image. For samples where the target elements have extremely low signal yields, the use of charge coupled device (CCD)-based detectors for this purpose can be problematic. At short acquisition times, the images produced by CCDs can be noisy and may contain fixed pattern artifacts that impact subsequent correlative alignment. Here we report on the use of direct electron detection devices (DDD's) to increase the signal to noise as compared with CCD's. A 3× improvement in signal is reported with a DDD versus a comparably formatted CCD, with equivalent dose on each detector. With the fast rolling-readout design of the DDD, the duty cycle provides a major benefit, as there is no dead time between successive frames.

An Interlaboratory Evaluation of Drift Tube Ion Mobility–Mass Spectrometry Collision Cross Section Measurements

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

Stow, Sarah M.; Causon, Tim J.; Zheng, Xueyun

Collision cross section (CCS) measurements resulting from ion mobility-mass spectrometry (IM-MS) experiments provide a promising orthogonal dimension of structural information in MS-based analytical separations. As with any molecular identifier, interlaboratory standardization must precede broad range integration into analytical workflows. In this study, we present a reference drift tube ion mobility mass spectrometer (DTIM-MS) where improvements on the measurement accuracy of experimental parameters influencing IM separations provide standardized drift tube, nitrogen CCS values (DTCCSN2) for over 120 unique ion species with the lowest measurement uncertainty to date. The reproducibility of these DTCCSN2 values are evaluated across three additional laboratories on amore » commercially available DTIM-MS instrument. The traditional stepped field CCS method performs with a relative standard deviation (RSD) of 0.29% for all ion species across the three additional laboratories. The calibrated single field CCS method, which is compatible with a wide range of chromatographic inlet systems, performs with an average, absolute bias of 0.54% to the standardized stepped field DTCCSN2 values on the reference system. The low RSD and biases observed in this interlaboratory study illustrate the potential of DTIM-MS for providing a molecular identifier for a broad range of discovery based analyses.« less

The importance of electrothermal terms in Ohm's law for magnetized spherical implosions

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

Davies, J. R., E-mail: jdav@lle.rochester.edu; Betti, R.; Chang, P.-Y.

2015-11-15

The magnetohydrodynamics (MHD) of magnetic-field compression in laser-driven spherical targets is considered. Magnetic-field evolution is cast in terms of an effective fluid velocity, a convective term resulting from resistivity gradients, a resistive diffusion term, and a source term. Effective velocity is the sum of fluid velocity, drift velocity, and heat-flux velocity, given by electron heat flux divided by electron enthalpy density, which has two components: the perpendicular or Nernst velocity and the cross-field velocity. The Nernst velocity compresses the magnetic field as the heat front moves into gas. The cross-field velocity leads to dynamo generation of an azimuthal magnetic field.more » It is proposed that the heat-flux velocity should be flux limited using a “Nernst” flux limiter independent of the thermal flux limiter but should not exceed it. The addition of the MHD routines to the 1D, Lagrangian hydrocode LILAC and the Eulerian version of the 2D hydrocode DRACO is described, and the codes are used to model a magnetized spherical compression on the OMEGA laser. Thermal flux limiting at a shock front is found to cause unphysical electron temperature gradients that lead to large, unphysical magnetic fields caused by the resistivity gradient, so thermal flux limiting in the gas is removed. The Nernst term reduces the benefits of magnetization in inertial fusion. A Nernst flux limiter ≤0.12 is required in the gas in order to agree with measured neutron yield and increases in the neutron-averaged ion temperature caused by magnetization. This corresponds to preventing the Nernst velocity from exceeding the shock velocity, which prevents significant decoupling of the magnetic field and gas compression.« less

The importance of electrothermal terms in Ohm's law for magnetized spherical implosions

DOE PAGES

Davies, J. R.; Betti, R.; Chang, P. -Y.; ...

2015-11-06

The magnetohydrodynamics (MHD) of magnetic-field compression in laser-driven spherical targets is considered. Magnetic-field evolution is cast in terms of an effective fluid velocity, a convective term resulting from resistivity gradients, a resistive diffusion term, and a source term. Effective velocity is the sum of fluid velocity, drift velocity, and heat-flux velocity, given by electron heat flux divided by electron enthalpy density, which has two components: the perpendicular or Nernst velocity and the cross-field velocity. The Nernst velocity compresses the magnetic field as a heat front moves into the gas. The cross-field velocity leads to dynamo generation of an azimuthal magneticmore » field. It is proposed that the heat-flux velocity should be flux limited using a “Nernst” flux limiter independent of the thermal flux limiter but should not exceed it. The addition of MHD routines to the 1-D, Lagrangian hydrocode LILAC and the Eulerian version of the 2-D hydrocode DRACO is described, and the codes are used to model a magnetized spherical compression on the OMEGA laser. Thermal flux limiting at a shock front is found to cause unphysical electron temperature gradients that lead to large, unphysical magnetic fields caused by the resistivity gradient, so thermal flux limiting in the gas is removed. The Nernst term reduces the benefits of magnetization in inertial fusion. In addition, a Nernst flux limiter ≤ 0.12 is required in the gas in order to agree with measured neutron yield and increases in the neutron-averaged ion temperature caused by magnetization. This corresponds to maintaining the Nernst velocity below the shock velocity, which prevents significant decoupling of the magnetic field and gas compression.« less

Development of a multi-cycle shear-compression testing for the modeling of severe plastic deformation

NASA Astrophysics Data System (ADS)

Pesin, A.; Pustovoytov, D.; Lokotunina, N.

2017-12-01

The mechanism of severe plastic deformation comes from very significant shear strain. Shear-compression testing of materials is complicated by the fact that a state of large equivalent strain with dominant shear strain is not easily achievable. This paper presents the novel technique of laboratory simulation of severe plastic deformation by multi-cycle shear-compression testing at room temperature with equivalent strain e=1…5. The specimen consisted of a parallelepiped having an inclined gauge section created by two diametrically opposed semi-circular slots which were machined at 45°. Height of the specimen was 50 mm, section dimensions were 25×25 mm, gauge thickness was 5.0 mm and gauge width was 6.0 mm. The specimen provided dominant shear strain in an inclined gauge-section. The level of shear strain and equivalent strain was controlled through adjustment of the height reduction of the specimen, load application direction and number of cycles of shear-compression. Aluminium alloy Al-6.2Mg-0.7Mn was used as a material for specimen. FE simulation and analysis of the stress-strain state were performed. The microstructure of the specimen after multi-cycle shear-compression testing with equivalent strain e=1…5 was examined by optical and scanning electron microscope.

Correction algorithm for online continuous flow δ13C and δ18O carbonate and cellulose stable isotope analyses

NASA Astrophysics Data System (ADS)

Evans, M. N.; Selmer, K. J.; Breeden, B. T.; Lopatka, A. S.; Plummer, R. E.

2016-09-01

We describe an algorithm to correct for scale compression, runtime drift, and amplitude effects in carbonate and cellulose oxygen and carbon isotopic analyses made on two online continuous flow isotope ratio mass spectrometry (CF-IRMS) systems using gas chromatographic (GC) separation. We validate the algorithm by correcting measurements of samples of known isotopic composition which are not used to estimate the corrections. For carbonate δ13C (δ18O) data, median precision of validation estimates for two reference materials and two calibrated working standards is 0.05‰ (0.07‰); median bias is 0.04‰ (0.02‰) over a range of 49.2‰ (24.3‰). For α-cellulose δ13C (δ18O) data, median precision of validation estimates for one reference material and five working standards is 0.11‰ (0.27‰); median bias is 0.13‰ (-0.10‰) over a range of 16.1‰ (19.1‰). These results are within the 5th-95th percentile range of subsequent routine runtime validation exercises in which one working standard is used to calibrate the other. Analysis of the relative importance of correction steps suggests that drift and scale-compression corrections are most reliable and valuable. If validation precisions are not already small, routine cross-validated precision estimates are improved by up to 50% (80%). The results suggest that correction for systematic error may enable these particular CF-IRMS systems to produce δ13C and δ18O carbonate and cellulose isotopic analyses with higher validated precision, accuracy, and throughput than is typically reported for these systems. The correction scheme may be used in support of replication-intensive research projects in paleoclimatology and other data-intensive applications within the geosciences.

SU-E-J-133: Evaluation of Inter- and Intra-Fractional Pancreas Tumor Residual Motions with Abdominal Compression

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

Li, Y; Shi, F; Tian, Z

2014-06-01

Purpose: Abdominal compression (AC) has been widely used to reduce pancreas motion due to respiration for pancreatic cancer patients undergoing stereotactic body radiotherapy (SBRT). However, the inter-fractional and intra-fractional patient motions may degrade the treatment. The purpose of this work is to study daily CBCT projections and 4DCT to evaluate the inter-fractional and intra-fractional pancreatic motions. Methods: As a standard of care at our institution, 4D CT scan was performed for treatment planning. At least two CBCT scans were performed for daily treatment. Retrospective studies were performed on patients with implanted internal fiducial markers or surgical clips. The initial motionmore » pattern was obtained by extracting marker positions on every phase of 4D CT images. Daily motions were presented by marker positions on CBCT scan projection images. An adaptive threshold segmentation algorithm was used to extract maker positions. Both marker average positions and motion ranges were compared among three sets of scans, 4D CT, positioning CBCT, and conformal CBCT, for inter-fractional and intra-fractional motion variations. Results: Data from four pancreatic cancer patients were analyzed. These patients had three fiducial markers implanted. All patients were treated by an Elekta Synergy with single fraction SBRT. CBCT projections were acquired by XVI. Markers were successfully detected on most of the projection images. The inter-fractional changes were determined by 4D CT and the first CBCT while the intra-fractional changes were determined by multiple CBCT scans. It is found that the average motion range variations are within 2 mm, however, the average marker positions may drift by 6.5 mm. Conclusion: The patients respiratory motion variation for pancreas SBRT with AC was evaluated by detecting markers from CBCT projections and 4DCT, both the inter-fraction and intra-fraction motion range change is small but the drift of marker positions may be comparable to motion ranges.« less

Spin-dependent limits from the DRIFT-IId directional dark matter detector

NASA Astrophysics Data System (ADS)

Daw, E.; Fox, J. R.; Gauvreau, J.-L.; Ghag, C.; Harmon, L. J.; Gold, M.; Lee, E. R.; Loomba, D.; Miller, E. H.; Murphy, A. Stj.; Paling, S. M.; Landers, J. M.; Pipe, M.; Pushkin, K.; Robinson, M.; Snowden-Ifft, D. P.; Spooner, N. J. C.; Walker, D.

2012-02-01

Data are presented from the DRIFT-IId detector operated in the Boulby Underground Science Facility in England. A 0.8 m3 fiducial volume, containing partial pressures of 30 Torr CS2 and 10 Torr CF4, was exposed for a duration of 47.4 live-time days with sufficient passive shielding to provide a neutron free environment within the detector. The nuclear recoil events seen are consistent with a remaining low-level background from the decay of radon daughters attached to the central cathode of the detector. However, charge from such events must drift across the entire width of the detector, and thus display large diffusion upon reaching the readout planes of the device. Exploiting this feature, it is shown to be possible to reject energy depositions from these Radon Progeny Recoil events while still retaining sensitivity to fiducial-volume nuclear recoil events. The response of the detector is then interpreted, using the F nuclei content of the gas, in terms of sensitivity to proton spin-dependent WIMP-nucleon interactions, displaying a minimum in sensitivity cross section at 1.8 pb for a WIMP mass of 100 GeV/c2. This sensitivity was achieved without compromising the direction sensitivity of DRIFT.

Ground-water resources in New Hampshire; stratified-drift aquifers

USGS Publications Warehouse

Medalie, Laura; Moore, R.B.

1995-01-01

Stratified-drift aquifers underlie about 14 percent of the land surface in New Hampshire and are an important source of ground water for commercial, industrial, domestic, and public-water supplies in the State. This report introduces terms and concepts relevant to ground-water resources, summarizes some of the important information derived from a statewide stratified-drift-aquifer investigation, and provides examples of how the findings are used . The purpose of this report is to provide an overview of the stratified-drift aquifer assessment program, thus making summary information accessible to a broad audience, including legislators, State and local officials, and the public. Different audiences will use the report in different ways . To accommodate the varied audiences, some data are summarized statewide, some are presented by major river basin, and some are provided by town. During data collection, care was taken to use consistent methods for each of the 13 study areas (fig. 1) so that results would be comparable throughout the State . If more specific or detailed information about a particular area of interest is needed, the reader is directed to one or more of the technical reports listed in the Selected References section of this report.

40 CFR 161.20 - Overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... product chemistry, residue chemistry, environmental fate, toxicology, reentry protection, aerial drift... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Overview. 161.20 Section 161.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS DATA REQUIREMENTS...

Physical mechanism causing rapid changes in ultrarelativistic electron pitch angle distributions right after a shock arrival: Evaluation of an electron dropout event: Drift Shell Splitting on the Dayside

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

Zhang, X. -J.; Li, W.; Thorne, R. M.

Three mechanisms have been proposed to explain relativistic electron flux depletions (dropouts) in the Earth's outer radiation belt during storm times: adiabatic expansion of electron drift shells due to a decrease in magnetic field strength, magnetopause shadowing and subsequent outward radial diffusion, and precipitation into the atmosphere (driven by EMIC wave scattering). Which mechanism predominates in causing electron dropouts commonly observed in the outer radiation belt is still debatable. In the present study, we evaluate the physical mechanism that may be primarily responsible for causing the sudden change in relativistic electron pitch angle distributions during a dropout event observed bymore » Van Allen Probes during the main phase of the 27 February 2014 storm. During this event, the phase space density of ultrarelativistic (>1MeV) electrons was depleted by more than 1 order of magnitude over the entire radial extent of the outer radiation belt (3 < L* < 5) in less than 6 h after the passage of an interplanetary shock. We model the electron pitch angle distribution under a compressed magnetic field topology based on actual solar wind conditions. Although these ultrarelativistic electrons exhibit highly anisotropic (peaked in 90°), energy-dependent pitch angle distributions, which appear to be associated with the typical EMIC wave scattering, comparison of the modeled electron distribution to electron measurements indicates that drift shell splitting is responsible for this rapid change in electron pitch angle distributions. This further indicates that magnetopause loss is the predominant cause of the electron dropout right after the shock arrival.« less

Physical mechanism causing rapid changes in ultrarelativistic electron pitch angle distributions right after a shock arrival: Evaluation of an electron dropout event: Drift Shell Splitting on the Dayside

DOE PAGES

Zhang, X. -J.; Li, W.; Thorne, R. M.; ...

2016-08-13

Three mechanisms have been proposed to explain relativistic electron flux depletions (dropouts) in the Earth's outer radiation belt during storm times: adiabatic expansion of electron drift shells due to a decrease in magnetic field strength, magnetopause shadowing and subsequent outward radial diffusion, and precipitation into the atmosphere (driven by EMIC wave scattering). Which mechanism predominates in causing electron dropouts commonly observed in the outer radiation belt is still debatable. In the present study, we evaluate the physical mechanism that may be primarily responsible for causing the sudden change in relativistic electron pitch angle distributions during a dropout event observed bymore » Van Allen Probes during the main phase of the 27 February 2014 storm. During this event, the phase space density of ultrarelativistic (>1MeV) electrons was depleted by more than 1 order of magnitude over the entire radial extent of the outer radiation belt (3 < L* < 5) in less than 6 h after the passage of an interplanetary shock. We model the electron pitch angle distribution under a compressed magnetic field topology based on actual solar wind conditions. Although these ultrarelativistic electrons exhibit highly anisotropic (peaked in 90°), energy-dependent pitch angle distributions, which appear to be associated with the typical EMIC wave scattering, comparison of the modeled electron distribution to electron measurements indicates that drift shell splitting is responsible for this rapid change in electron pitch angle distributions. This further indicates that magnetopause loss is the predominant cause of the electron dropout right after the shock arrival.« less

PACE: Power-Aware Computing Engines

DTIC Science & Technology

2005-02-01

more costly than compu- tation on our test platform, and it is memory access that dominates most lossless data compression algorithms . In fact, even...Performance and implementation concerns A compression algorithm may be implemented with many different, yet reasonable, data structures (including...Related work This section discusses data compression for low- bandwidth devices and optimizing algorithms for low energy. Though much work has gone

49 CFR 173.302b - Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure receptacles. 173.302b Section 173.302b Transportation... cylinder. The use of UN tubes and MEGCs is not authorized. (e) Carbon monoxide, compressed UN 1016. Carbon...

49 CFR 173.302b - Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure...

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Additional requirements for shipment of non-liquefied (permanent) compressed gases in UN pressure receptacles. 173.302b Section 173.302b Transportation... cylinder. The use of UN tubes and MEGCs is not authorized. (e) Carbon monoxide, compressed UN 1016. Carbon...

Design and evaluation of a bolted joint for a discrete carbon-epoxy rod-reinforced hat section

NASA Technical Reports Server (NTRS)

Rousseau, Carl Q.; Baker, Donald J.

1996-01-01

The use of prefabricated pultruded carbon-epoxy rods has reduced the manufacturing complexity and costs of stiffened composite panels while increasing the damage tolerance of the panels. However, repairability of these highly efficient discrete stiffeners has been a concern. Design, analysis, and test results are presented in this paper for a bolted-joint repair for the pultruded rod concept that is capable of efficiently transferring axial loads in a hat-section stiffener on the upper skin segment of a heavily loaded aircraft wing component. A tension and a compression joint design were evaluated. The tension joint design achieved approximately 1.0% strain in the carbon-epoxy rod-reinforced hat-section and failed in a metal fitting at 166% of the design ultimate load. The compression joint design failed in the carbon-epoxy rod-reinforced hat-section test specimen area at approximately 0.7% strain and at 110% of the design ultimate load. This strain level of 0.7% in compression is similar to the failure strain observed in previously reported carbon-epoxy rod-reinforced hat-section column tests.

Modeling Food Delivery Dynamics For Juvenile Salmonids Under Variable Flow Regimes

NASA Astrophysics Data System (ADS)

Harrison, L.; Utz, R.; Anderson, K.; Nisbet, R.

2010-12-01

Traditional approaches for assessing instream flow needs for salmonids have typically focused on the importance of physical habitat in determining fish habitat selection. This somewhat simplistic approach does not account for differences in food delivery rates to salmonids that arise due to spatial variability in river morphology, hydraulics and temporal variations in the flow regime. Explicitly linking how changes in the flow regime influences food delivery dynamics is an important step in advancing process-based bioenergetic models that seek to predict growth rates of salmonids across various life-stages. Here we investigate how food delivery rates for juvenile salmonids vary both spatially and with flow magnitude in a meandering reach of the Merced River, CA. We utilize a two-dimensional (2D) hydrodynamic model and discrete particle tracking algorithm to simulate invertebrate drift transport rates at baseflow and a near-bankfull discharge. Modeling results indicate that at baseflow, the maximum drift density occurs in the channel thalweg, while drift densities decrease towards the channel margins due to the process of organisms settling out of the drift. During high-flow events, typical of spring dam-releases, the invertebrate drift transport pathway follows a similar trajectory along the high velocity core and the drift concentrations are greatest in the channel centerline, though the zone of invertebrate transport occupies a greater fraction of the channel width. Based on invertebrate supply rates alone, feeding juvenile salmonids would be expected to be distributed down the channel centerline where the maximum predicted food delivery rates are located in this reach. However, flow velocities in these channel sections are beyond maximum sustainable swimming speeds for most juvenile salmonids. Our preliminary findings suggest that a lack of low velocity refuge may prevent juvenile salmonids from deriving energy from the areas with maximum drift density in this reach. Future efforts will focus on integration of food delivery and bioenergetic models to account for conflicting demands of maximizing food intake while minimizing the energetic costs of swimming.

Sequential buckling of an elastic wall

NASA Astrophysics Data System (ADS)

Bico, Jose; Bense, Hadrien; Keiser, Ludovic; Roman, Benoit; Melo, Francisco; Abkarian, Manouk

A beam under quasistatic compression classically buckles beyond a critical threshold. In the case of a free beam, the lowest buckling mode is selected. We investigate the case of a long ``wall'' grounded of a compliant base and compressed in the axial compression. In the case of a wall of slender rectangular cross section, the selected buckling mode adopts a nearly fixed wavelength proportional to the height of the wall. Higher compressive loads only increase the amplitude of the buckle. However if the cross section has a sharp shape (such as an Eiffel tower profile), we observe successive buckling modes of increasing wavelength. We interpret this unusual evolution in terms of scaling arguments. At small scales, this variable periodicity might be used to develop tunable optical devices. We thank ECOS C12E07, CNRS-CONICYT, and Fondecyt Grant No. N1130922 for partially funding this work.

Nimbus 7 solar backscatter ultraviolet (SBUV) ozone products user's guide

NASA Technical Reports Server (NTRS)

Fleig, Albert J.; Mcpeters, R. D.; Bhartia, P. K.; Schlesinger, Barry M.; Cebula, Richard P.; Klenk, K. F.; Taylor, Steven L.; Heath, Donald F.

1990-01-01

Three ozone tape products from the Solar Backscatter Ultraviolet (SBUV) experiment aboard Nimbus 7 were archived at the National Space Science Data Center. The experiment measures the fraction of incoming radiation backscattered by the Earth's atmosphere at 12 wavelengths. In-flight measurements were used to monitor changes in the instrument sensitivity. Total column ozone is derived by comparing the measurements with calculations of what would be measured for different total ozone amounts. The altitude distribution is retrieved using an optimum statistical technique for the inversion. The estimated initial error in the absolute scale for total ozone is 2 percent, with a 3 percent drift over 8 years. The profile error depends on latitude and height, smallest at 3 to 10 mbar; the drift increases with increasing altitude. Three tape products are described. The High Density SBUV (HDSBUV) tape contains the final derived products - the total ozone and the vertical ozone profile - as well as much detailed diagnostic information generated during the retrieval process. The Compressed Ozone (CPOZ) tape contains only that subset of HDSBUV information, including total ozone and ozone profiles, considered most useful for scientific studies. The Zonal Means Tape (ZMT) contains daily, weekly, monthly and quarterly averages of the derived quantities over 10 deg latitude zones.

Direct-reading design charts for 75S-T6 aluminum-alloy flat compression panels having longitudinal extruded Z-section stiffeners

NASA Technical Reports Server (NTRS)

Hickman, William A; Dow, Norris F

1951-01-01

Direct-reading design charts are presented for 75S-T6 aluminum-alloy flat compression panels having longitudinal extruded Z-section stiffeners. These charts, which cover a wide range of proportions, make possible the direct determination of the stress and all panel dimensions required to carry a given intensity of loading with a given skin thickness and effective length of panel.

Casing for a gas turbine engine

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

Wiebe, David J.; Little, David A.; Charron, Richard C.

2016-07-12

A casing for a can annular gas turbine engine, including: a compressed air section (40) spanning between a last row of compressor blades (26) and a first row of turbine blades (28), the compressed air section (40) having a plurality of openings (50) there through, wherein a single combustor/advanced duct assembly (64) extends through each opening (50); and one top hat (68) associated with each opening (50) configured to enclose the associated combustor/advanced duct assembly (64) and seal the opening (50). A volume enclosed by the compressed air section (40) is not greater than a volume of a frustum (54)more » defined at an upstream end (56) by an inner diameter of the casing at the last row of compressor blades (26) and at a downstream end (60) by an inner diameter of the casing at the first row of turbine blades (28).« less

Measuring the resolution of uncompressed plastic sections cut using an oscillating knife ultramicrotome.

PubMed

Sader, Kasim; Reedy, Michael; Popp, David; Lucaveche, Carmen; Trinick, John

2007-07-01

Thin sections of biological tissue embedded in plastic and cut with an ultramicrotome do not generally display useful details smaller than approximately 50 A in the electron microscope. However, there is evidence that before sectioning the embedded tissue can be substantially better preserved, which suggests that cutting is when major damage and loss of resolution occurs. We show here a striking example of such damage in embedded insect flight muscle fibres. X-ray diffraction of the embedded muscle gave patterns extending to 13A, whereas sections cut from the same block showed only approximately 50 A resolution. A possible source of this damage is the substantial compression that was imposed on sections during cutting. An oscillating knife ultramicrotome eliminates the compression and it seemed possible that sections cut with such a knife would show substantially improved preservation. We used the oscillating knife to cut sections from the embedded muscle and from embedded catalase crystals. Preservation with and without oscillation was assessed in Fourier transforms of micrographs. Sections cut with the knife oscillating did not show improved preservation over those cut without. Thus compression during cutting does not appear to be the major source of damage in plastic sections, and leaves unexplained the 50 A versus 13A discrepancy between block and section preservation. The results nevertheless suggest that improvements in ultramicrotomy will be important for bringing thin-sectioning and tomography of plastic-embedded cells and tissues to the point where macromolecule shapes can be resolved.

Dayside response of the magnetosphere to a small shock compression: Van Allen Probes, Magnetospheric MultiScale, and GOES-13

NASA Astrophysics Data System (ADS)

Cattell, C.; Breneman, A.; Colpitts, C.; Dombeck, J.; Thaller, S.; Tian, S.; Wygant, J.; Fennell, J.; Hudson, M. K.; Ergun, Robert; Russell, C. T.; Torbert, Roy; Lindqvist, Per-Arne; Burch, J.

2017-09-01

Observations from Magnetospheric MultiScale ( 8 Re) and Van Allen Probes ( 5 and 4 Re) show that the initial dayside response to a small interplanetary shock is a double-peaked dawnward electric field, which is distinctly different from the usual bipolar (dawnward and then duskward) signature reported for large shocks. The associated E × B flow is radially inward. The shock compressed the magnetopause to inside 8 Re, as observed by Magnetospheric MultiScale (MMS), with a speed that is comparable to the E × B flow. The magnetopause speed and the E × B speeds were significantly less than the propagation speed of the pulse from MMS to the Van Allen Probes and GOES-13, which is consistent with the MHD fast mode. There were increased fluxes of energetic electrons up to several MeV. Signatures of drift echoes and response to ULF waves also were seen. These observations demonstrate that even very weak shocks can have significant impact on the radiation belts.

Compression testing of thick-section composite materials

NASA Astrophysics Data System (ADS)

Camponeschi, Eugene T., Jr.

A compression test fixture suitable for testing of composites up to 1 inch in thickness has been developed with a view to the characterization of the effects of constituents, fiber orientation, and thickness, on the compressive response of composites for naval applications. The in-plane moduli, compression strength, failure mechanisms, and both in-plane and through-thickness Poisson's ratios are shown to be independent of material thickness. The predominant failure mechanisms for both materials, namely kink bands and delaminations, are identical to those reported for composite one-tenth the thickness of those presently tested.

40 CFR 170.160 - Emergency assistance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Emergency assistance. 170.160 Section 170.160 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS..., splash, spill, drift, or pesticide residues, the agricultural employer shall: (a) Make available to that...

40 CFR 170.160 - Emergency assistance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Emergency assistance. 170.160 Section 170.160 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS..., splash, spill, drift, or pesticide residues, the agricultural employer shall: (a) Make available to that...

40 CFR 170.260 - Emergency assistance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Emergency assistance. 170.260 Section 170.260 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... from handling tasks or from application, splash, spill, drift, or pesticide residues, the handler...

40 CFR 170.160 - Emergency assistance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Emergency assistance. 170.160 Section 170.160 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS..., splash, spill, drift, or pesticide residues, the agricultural employer shall: (a) Make available to that...

40 CFR 170.260 - Emergency assistance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Emergency assistance. 170.260 Section 170.260 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... from handling tasks or from application, splash, spill, drift, or pesticide residues, the handler...

40 CFR 170.260 - Emergency assistance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Emergency assistance. 170.260 Section 170.260 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... from handling tasks or from application, splash, spill, drift, or pesticide residues, the handler...

40 CFR 170.260 - Emergency assistance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Emergency assistance. 170.260 Section 170.260 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... from handling tasks or from application, splash, spill, drift, or pesticide residues, the handler...

40 CFR 170.160 - Emergency assistance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Emergency assistance. 170.160 Section 170.160 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS..., splash, spill, drift, or pesticide residues, the agricultural employer shall: (a) Make available to that...

40 CFR 170.160 - Emergency assistance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Emergency assistance. 170.160 Section 170.160 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS..., splash, spill, drift, or pesticide residues, the agricultural employer shall: (a) Make available to that...

40 CFR 170.260 - Emergency assistance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Emergency assistance. 170.260 Section 170.260 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... from handling tasks or from application, splash, spill, drift, or pesticide residues, the handler...

Distribution of Particles in the Z-axis of Tissue Sections: Relevance for Counting Methods.

PubMed

von Bartheld, Christopher S

2012-01-01

The distribution of particles in the z-axis of thick tissue sections has gained considerable attention, primarily because of implications for the accuracy of modern stereological counting methods. Three major types of artifacts can affect these sections: loss of particles from the surfaces of tissue sections (lost caps), homogeneous collapse in the z-axis, and differential deformation in the z-axis. Initially it was assumed that thick sections were not compromised by differential shrinkage or compression (differential uniform deformation). Studies in the last decade showed that such artifacts are common and that they depend on embedding media and sectioning devices. Paraffin, glycolmethacrylate and vibratome sections are affected by this artifact, but not celloidin sections or cryostat-derived cryosections. Differential distribution of particles in the z-axis is likely due to compression of the surface areas (margins) during sectioning, resulting in differential particle densities in the core and margin of tissue sections. This deformation of tissue sections can be rapidly assessed by measuring the position of particles in the z-axis. The analysis is complicated by potential secondary effects on section surfaces through loss of particles, the so-called "lost caps" phenomenon. Secondary effects necessitate the use of guard spaces, while their use in case of primary effects (compression due to sectioning) would enhance the artifact's impact on bias. Symmetric versus asymmetric patterns of z-axis distortion can give clues to distinguish primary and secondary effects. Studies that use the optical disector need to take these parameters into account to minimize biases.

Design and Evaluation of a Bolted Joint for a Discrete Carbon-Epoxy Rod-Reinforced Hat Section

NASA Technical Reports Server (NTRS)

Baker, Donald J.; Rousseau, Carl Q.

1996-01-01

The use of pre-fabricated pultruded carbon-epoxy rods has reduced the manufacturing complexity and costs of stiffened composite panels while increasing the damage tolerance of the panels. However, repairability of these highly efficient discrete stiffeners has been a concern. Design, analysis, and test results are presented in this paper for a bolted-joint repair for the pultruded rod concept that is capable of efficiently transferring axial loads in a hat-section stiffener on the upper skin segment of a heavily loaded aircraft wing component. A tension and a compression joint design were evaluated. The tension joint design achieved approximately 1.0 percent strain in the carbon-epoxy rod-reinforced hat-section and failed in a metal fitting at 166 percent of the design ultimate load. The compression joint design failed in the carbon-epoxy rod-reinforced hat-section test specimen area at approximately 0.7 percent strain and at 110 percent of the design ultimate load. This strain level of 0.7 percent in compression is similar to the failure strain observed in previously reported carbon-epoxy rod-reinforced hat-section column tests.

40 CFR 94.12 - Interim provisions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... differences in testing will not affect NOX emission rates. (g) Flexibility for engines over 560kW... EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES General Provisions for Emission Regulations for Compression-Ignition Marine Engines § 94.12 Interim provisions. This section contains provisions that apply...

40 CFR 94.12 - Interim provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... differences in testing will not affect NOX emission rates. (g) Flexibility for engines over 560kW...) CONTROL OF EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES General Provisions for Emission Regulations for Compression-Ignition Marine Engines § 94.12 Interim provisions. This section contains provisions...

40 CFR 94.12 - Interim provisions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... differences in testing will not affect NOX emission rates. (g) Flexibility for engines over 560kW...) CONTROL OF EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES General Provisions for Emission Regulations for Compression-Ignition Marine Engines § 94.12 Interim provisions. This section contains provisions...

40 CFR 94.12 - Interim provisions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... differences in testing will not affect NOX emission rates. (g) Flexibility for engines over 560kW...) CONTROL OF EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES General Provisions for Emission Regulations for Compression-Ignition Marine Engines § 94.12 Interim provisions. This section contains provisions...

40 CFR 94.12 - Interim provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... differences in testing will not affect NOX emission rates. (g) Flexibility for engines over 560kW...) CONTROL OF EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES General Provisions for Emission Regulations for Compression-Ignition Marine Engines § 94.12 Interim provisions. This section contains provisions...

40 CFR 94.4 - Treatment of confidential information.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... 94.4 Section 94.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES General Provisions for Emission Regulations for Compression-Ignition Marine Engines § 94.4 Treatment of confidential information. (a) Any...

Accounting For Compressibility In Viscous Flow In Pipes

NASA Technical Reports Server (NTRS)

Steinle, Frank W.; Gee, Ken; Murthy, Sreedhara V.

1991-01-01

Method developed to account for effects of compressibility in viscous flows through long, circular pipes of uniform diameter. Based on approximation of variations in density and velocity across pipe cross section by profile equations developed for boundary-layer flow between flat plates.

Experimental observations and finite element analysis of the initiation of fiber microbuckling in notched composite laminates

NASA Technical Reports Server (NTRS)

Guynn, E. Gail; Bradley, Walter L.

1989-01-01

An understanding was developed of the factors that determine the semi-circular edge-notched compressive strength and the associated failure mode(s) were identified of thermoplastic composite laminates with multidirectional stacking sequences. The experimental observations and the detailed literature review suggest at least four factors that affected the determination of the strain levels at which fiber microbuckling initiates and thus, partially control the composite's compression strength. The dependent variables studied are the compressive strength of a reduced gage section compression specimen and the compression strength of a compression specimen with two semi-circular edge notches (no opposite free edges) centered along the gage section. In this research, specimens containing two semi-circular edge notches (no opposite free edges) were loaded in compression at a relatively slow rate to provide more stable development of fiber microbuckling damage. The results indicate that the local constraints (free surfaces, supporting ply orientation, and resin-rich regions) significantly affect the strain level for the initiation of in-plane fiber microbuckling. Preliminary results at an elevated temperature, 77 C, showed the shear stress yield strength of the resin was reduced and consequently, the resistance to fiber microbuckling was also reduced. The finite element analysis of the perfectly straight fiber problem indicates that the free surface effect causes a 10 percent reduction in the critical buckling strain. However, the experimentally measured reduction for fibers with an initial fiber curvature, was 35 percent.

Accurate Drift Time Determination by Traveling Wave Ion Mobility Spectrometry: The Concept of the Diffusion Calibration.

PubMed

Kune, Christopher; Far, Johann; De Pauw, Edwin

2016-12-06

Ion mobility spectrometry (IMS) is a gas phase separation technique, which relies on differences in collision cross section (CCS) of ions. Ionic clouds of unresolved conformers overlap if the CCS difference is below the instrumental resolution expressed as CCS/ΔCCS. The experimental arrival time distribution (ATD) peak is then a superimposition of the various contributions weighted by their relative intensities. This paper introduces a strategy for accurate drift time determination using traveling wave ion mobility spectrometry (TWIMS) of poorly resolved or unresolved conformers. This method implements through a calibration procedure the link between the peak full width at half-maximum (fwhm) and the drift time of model compounds for wide range of settings for wave heights and velocities. We modified a Gaussian equation, which achieves the deconvolution of ATD peaks where the fwhm is fixed according to our calibration procedure. The new fitting Gaussian equation only depends on two parameters: The apex of the peak (A) and the mean drift time value (μ). The standard deviation parameter (correlated to fwhm) becomes a function of the drift time. This correlation function between μ and fwhm is obtained using the TWIMS calibration procedure which determines the maximum instrumental ion beam diffusion under limited and controlled space charge effect using ionic compounds which are detected as single conformers in the gas phase. This deconvolution process has been used to highlight the presence of poorly resolved conformers of crown ether complexes and peptides leading to more accurate CCS determinations in better agreement with quantum chemistry predictions.

49 CFR 173.302a - Additional requirements for shipment of nonliquefied (permanent) compressed gases in...

Code of Federal Regulations, 2010 CFR

2010-10-01

... nonliquefied (permanent) compressed gases in specification cylinders. 173.302a Section 173.302a Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND...

29 CFR 1910.166-1910.168 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 5 2010-07-01 2010-07-01 false [Reserved] 1910.166-1910.168 Section 1910.166-1910.168 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Compressed Gas and Compressed Air Equipment...

Investigation of Mild Steel Thin-Wall Tubes in Unfilled and Foam-Filled Triangle, Square, and Hexagonal Cross Sections Under Compression Load

NASA Astrophysics Data System (ADS)

Rajak, Dipen Kumar; Kumaraswamidhas, L. A.; Das, S.

2018-02-01

This study has examined proposed structures with mild steel-reinforced LM30 aluminum (Al) alloy having diversely unfilled and 10 wt.% SiCp composite foam-filled tubes for improving axial compression performance. This class of material has novel physical, mechanical, and electrical properties along with low density. In the present experiment, Al alloy foams were prepared by the melt route technique using metal hydride powder as a foaming agent. Crash energy phenomena for diverse unfilled and foam-filled in mild steel thin-wall tubes (triangular, square and hexagonal) were studied as well. Compression deformation investigation was conducted at strain rates of 0.001-0.1/s for evaluating specific energy absorption (SEA) under axial loading conditions. The results were examined to measure plateau stress, maximum densification strain, and deformation mechanism of the materials. Specific energy absorption and total energy absorption capacities of the unfilled and filled sections were determined from the compressive stress-strain curves, which were then compared with each other.

Spatiotemporal splitting of global eigenmodes due to cross-field coupling via vortex dynamics in drift wave turbulence.

PubMed

Brandt, C; Thakur, S C; Light, A D; Negrete, J; Tynan, G R

2014-12-31

Spatiotemporal splitting events of drift wave (DW) eigenmodes due to nonlinear coupling are investigated in a cylindrical helicon plasma device. DW eigenmodes in the radial-azimuthal cross section have been experimentally observed to split at radial locations and recombine into the global eigenmode with a time shorter than the typical DW period (t≪fDW(-1)). The number of splits correlates with the increase of turbulence. The observed dynamics can be theoretically reproduced by a Kuramoto-type model of a network of radially coupled azimuthal eigenmodes. Coupling by E×B-vortex convection cell dynamics and ion gyro radii motion leads to cross-field synchronization and occasional mode splitting events.

40 CFR 60.4880 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2012 CFR

2012-07-01

... section are met. (A) The zero (low-level), mid-level (if applicable), or high-level calibration drift... representative of the relative or absolute particulate matter loadings for each exhaust stack, roof vent, or...

40 CFR 60.4880 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2014 CFR

2014-07-01

... section are met. (A) The zero (low-level), mid-level (if applicable), or high-level calibration drift... representative of the relative or absolute particulate matter loadings for each exhaust stack, roof vent, or...

40 CFR 60.4880 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2013 CFR

2013-07-01

... section are met. (A) The zero (low-level), mid-level (if applicable), or high-level calibration drift... representative of the relative or absolute particulate matter loadings for each exhaust stack, roof vent, or...

Accessing defect dynamics using intense, nanosecond pulsed ion beams

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

Persaud, A.; Barnard, J. J.; Guo, H.

2015-06-18

Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystalmore » Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.« less

Analytical Description of Degradation-Relaxation Transformations in Nanoinhomogeneous Spinel Ceramics.

PubMed

Shpotyuk, O; Brunner, M; Hadzaman, I; Balitska, V; Klym, H

2016-12-01

Mathematical models of degradation-relaxation kinetics are considered for jammed thick-film systems composed of screen-printed spinel Cu 0.1 Ni 0.1 Co 1.6 Mn 1.2 O 4 and conductive Ag or Ag-Pd alloys. Structurally intrinsic nanoinhomogeneous ceramics due to Ag and Ag-Pd diffusing agents embedded in a spinel phase environment are shown to define governing kinetics of thermally induced degradation under 170 °C obeying an obvious non-exponential behavior in a negative relative resistance drift. The characteristic stretched-to-compressed exponential crossover is detected for degradation-relaxation kinetics in thick-film systems with conductive contacts made of Ag-Pd and Ag alloys. Under essential migration of a conductive phase, Ag penetrates thick-film spinel ceramics via a considerable two-step diffusing process.

Elastic plate flexure above mantle plumes explains the upstream offset of volcanic activity at la Réunion and Hawaii

NASA Astrophysics Data System (ADS)

Gerbault, Muriel; Fontaine, Fabrice; Rabinowicz, Michel; Bystricky, Micha

2017-04-01

Surface volcanism at la Réunion and Hawaii occurs with an offset of 150-180 km upstream to the plume axis with respect to the plate motion. This striking observation raises questions about the forcing of plume-lithosphere thermo-mechanical interactions on melt trajectories beneath these islands. Based on visco-elasto-plastic numerical models handled at kilometric resolution, we propose to explain this offset by the development of compressional stresses at the base of the lithosphere, that result from elastic plate bending above the upward load exerted by the plume head. This horizontal compression adopts a disc shape centered around the plume axis, 20 km thick and 150 km in radius, at 50-70 km depth where the temperature varies from 600°C to 750°C. It lasts for 5 to 10 My in an oceanic plate of age greater than 70 My, a timing that is controlled by the visco-elastic relaxation time at 50-70 km depth. This period of time exceeds the time during which both the Somalian/East-African and Pacific plates drift over the Reunion and Hawaii plumes, respectively, thus rendering this basal compression a persistent feature. It is inferred that the buoyant melts percolating in the plume head pond below this zone of compression and eventually spread laterally until the most compressive principal elastic stresses reverse to the vertical, i.e., 150 km away from the plume head. There, melts propagate through dikes upwards to 35 km depth, where the plate curvature reverses and ambient compression diminishes. This 30-35 km depth may thus host magmatic reservoirs where melts pond, until further differentiation can relaunch ascension up to the surface and form a volcanic edifice. In a second stage, as the volcano grows because of melt accumulation at the top of the plate, the lithosphere is flexed downwards, inducing extra tensile stress at 30-35 km depth and compression at 15 km depth. It implies that now the melts pond at 15 km and form another magmatic reservoir lying just underneath the crust. These two processes explain the ponding of primary (shield) melts at 35 km and 15 km depths as partialy recorded below La Reunion, Mauritius or Hawaii volcanoes with seismic tomography.

One and two fluid numerical investigations of solar wind gas releases

NASA Astrophysics Data System (ADS)

Harold, James Benedict

1993-01-01

The dynamics of gas releases into high Mach number flowing plasmas are investigated. Emphasis is placed on systems of intermediate magnetization for which the scale size of the release lies between the ion and electron Larmor radii. The study is motivated by the December 1984 AMPTE (Active Magnetospheric Particle Tracer Explorer) solar wind barium release in which, contrary to the predictions of MHD theory, the barium cloud shifted transverse to the solar wind (in the uwind x B0 direction) before eventually turning downstream. Particular emphasis is given to identifying mechanisms responsible for this lateral motion. A modified MHD cold fluid approach that takes advantage of the supersonic nature of the problem forms the basis of this work. Two specific models are developed which incorporate large effective ion Larmor radius effects. The first is for a single ion species, the second for two ion species. Two physical effects are identified which are not present in the conventional MHD system: the Hall effect, based on a Hall magnetic drift wave, and a hybrid electrostatic ion cyclotron mode. Linear analysis shows that the effect of the Hall term is to propagate the upwind magnetic field compression azimuthally to the downwind side of the cloud, leading to a quasi-steady state field compression on the -uwind x BO side of the cloud. The cyclotron mode can lead to a similar compression through deflection of the solar wind ions into the uwind x BO direction. In each case the resulting compression leads to a transverse acceleration of the cloud. The relative importance of these two mechanisms is shown to depend on deltac / rc, the ratio of the collisionless skin depth to the cloud size. Nonlinear, two-dimensional simulations are performed for each model. These simulations produce the expected field compressions and the resultant lateral acceleration, in general qualitative agreement with the AMPTE experiment. The dependence of these mechanisms on the ratio deltac / rc is demonstrated. While no simulations are performed that precisely duplicate the parameters of the AMPTE release, the results suggest that the Hall effect, and possibly deflection of the solar wind by the cyclotron mode, constitute plausible mechanisms for the AMPTE shift.

New constraints on the crustal structure in the eastern part of northern Baffin Bay

NASA Astrophysics Data System (ADS)

Reichert, C. J.; Damm, V.; Altenbernd, T.; Berglar, K.; Block, M.; Ehrhardt, A.; Schnabel, M.

2010-12-01

The northern Baffin Bay is a key area for testing plate kinematic models for the Paleocene-Eocene motion of Greenland relative to North America and to decipher the evolution of the thick sedimentary basins in this area. In summer 2010, a multidisciplinary marine geoscientific expedition focusing on the Greenland part of northern Baffin Bay was performed under the direction of the Federal Institute for Geosciences and Natural Resources Hannover, Germany in cooperation with the Alfred-Wegener Institute Bremerhaven. Using 70 days ship time onboard the German R/V Polarstern a comprehensive data set was acquired along profiles extending from the deep oceanic basin in the central part of North Baffin Bay onto the Greenland continental margin in an area which was bordered by the Kane Basin in the North and Disco Island in the South. By means of multi-channel seismic, wide angle seismic, gravimetric and magnetic methods the structural inventory of the crust in the NW Baffin Bay was investigated. Additionally, heat flow data and sediment cores were collected at selected positions along lines across the Greenland continental margin. The cores were extracted for geochemical and geomicrobiological analysis to be used for basin modeling and studying the hydrocarbon potential. Aeromagnetic data was acquired covering part of the marine survey area to investigate magnetic signatures of the oceanic crust and the continental margin. In our presentation we will give an overview of the first results of the expedition with special focus on multi-channel seismic data. With a total length of 3500 km, the initial interpretation of multi-channel seismic data shows that the West Greenland margin is a typical passive continental margin with large rotated basement blocks, listric faults facing mainly seaward, and deep syn-rift-basins in between. The most prominent reflector under the shelf and the slope probably indicates the transition from rifting to drifting and therefore the beginning of seafloor spreading in the Baffin Bay. This is suggested by erosion on top of basement blocks, subsidence along the slope area, and termination of the prominent reflector in the area of the ocean-continent boundary. The syn-rift sediments were deposited in two single phases, which could be imaged along several sections of the newly acquired seismic lines. The Quaternary and late Pliocene glacial deposits are characterized by prograding sequences on the western shelf and the upper slope. Some lines show that the NNW striking Melville Ridge is a compression structure generated by thrusting of the Melville graben sedimentary fill on its western edge. We interpret the compression as a result of strike slip faulting in conjunction with the northward movement of Greenland in the second drift phase starting in the Eocene. At some segments of the crustal margin the opening of the Baffin Bay might be associated with volcanic activity.

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2014 CFR

2014-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2010 CFR

2010-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2013 CFR

2013-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2012 CFR

2012-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

14 CFR 125.226 - Digital flight data recorders.

Code of Federal Regulations, 2011 CFR

2011-01-01

... this section, no person may operate under this part a turbine-engine-powered transport category... selection; (37) Drift angle (when an information source is installed); (38) Wind speed and direction (when... rudder valve status. (b) For all turbine-engine powered transport category airplanes manufactured on or...

Rapid acceleration of outer radiation belt electrons associated with solar wind pressure pulse: Simulation study with Arase and Van Allen Probe observations

NASA Astrophysics Data System (ADS)

Hayashi, M.; Yoshizumi, M.; Saito, S.; Matsumoto, Y.; Kurita, S.; Teramoto, M.; Hori, T.; Matsuda, S.; Shoji, M.; Machida, S.; Amano, T.; Seki, K.; Higashio, N.; Mitani, T.; Takashima, T.; Kasahara, Y.; Kasaba, Y.; Yagitani, S.; Ishisaka, K.; Tsuchiya, F.; Kumamoto, A.; Matsuoka, A.; Shinohara, I.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.

2017-12-01

Relativistic electron fluxes of the outer radiation belt rapidly change in response to solar wind variations. One of the shortest acceleration processes of electrons in the outer radiation belt is wave-particle interactions between drifting electrons and fast-mode waves induced by compression of the dayside magnetopause caused by interplanetary shocks. In order to investigate this process by a solar wind pressure pulse, we perform a code-coupling simulation using the GEMSIS-RB test particle simulation (Saito et al., 2010) and the GEMSIS-GM global MHD magnetosphere simulation (Matsumoto et al., 2010). As a case study, an interplanetary pressure pulse with the enhancement of 5 nPa is used as the up-stream condition. In the magnetosphere, the fast mode waves with the azimuthal electric field ( negative 𝐸𝜙 : |𝐸&;#120601;| 10 mV/m, azimuthal mode number : m ≤ 2) propagates from the dayside to nightside, interacting with electrons. From the simulation results, we derived effective acceleration model and condition : The electrons whose drift velocities vd ≥ (π/2)Vfast are accelerated efficiently. On December 20, 2016, the Arase (ERG) satellite was launched , allowing more accurate multi-point simultaneous observation with other satellites. We will compare our simulation results with observations from Arase and Van Allen Probes, and investigate the acceleration condition of relativistic electrons associated with storm sudden commencement (SSC).

30 CFR 7.506 - Breathable air components.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Breathable air components. 7.506 Section 7.506... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Refuge Alternatives § 7.506 Breathable air components. (a) Breathable air shall be supplied by compressed air cylinders, compressed breathable-oxygen...

30 CFR 7.506 - Breathable air components.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Breathable air components. 7.506 Section 7.506... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Refuge Alternatives § 7.506 Breathable air components. (a) Breathable air shall be supplied by compressed air cylinders, compressed breathable-oxygen...

30 CFR 7.506 - Breathable air components.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Breathable air components. 7.506 Section 7.506... APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Refuge Alternatives § 7.506 Breathable air components. (a) Breathable air shall be supplied by compressed air cylinders, compressed breathable-oxygen...

46 CFR 194.15-17 - Compressed gases other than inert gases.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Compressed gases other than inert gases. 194.15-17 Section 194.15-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and...

46 CFR 194.15-15 - Chemicals other than compressed gases.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Chemicals other than compressed gases. 194.15-15 Section 194.15-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and...

46 CFR 194.15-17 - Compressed gases other than inert gases.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Compressed gases other than inert gases. 194.15-17 Section 194.15-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and...

46 CFR 194.15-15 - Chemicals other than compressed gases.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Chemicals other than compressed gases. 194.15-15 Section 194.15-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OCEANOGRAPHIC RESEARCH VESSELS HANDLING, USE, AND CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and...

The effect of methylprednisolone on facial nerve paralysis with different etiologies.

PubMed

Yildirim, Mehmet Akif; Karlidag, Turgut; Akpolat, Nusret; Kaygusuz, Irfan; Keles, Erol; Yalcin, Sinasi; Akyigit, Abdulvahap

2015-05-01

The objective of this study was to evaluate the effectiveness of methylprednisolone (MP) in models of facial nerve paralysis obtained by nerve section, compression, or inoculation with herpes simplex virus (HSV). Experimental controlled animal study. Tertiary referral center. A total of 30 female New Zealand rabbits weighing 1200-3000 g were used for the study. They were randomly assigned to one of 6 groups of 5 animals each. A nerve section injury was realized in Groups 1a (section and MP) and 1b (section, control) rabbits. A compression-type injury was inflicted to rabbits in Groups 2a (compression and MP) and 2b (compression, control). As for animals in Groups 3a (Type 1 HSV and MP) and 3b (Type 1 HSV, controls), facial nerve paralysis resulting from viral infection was obtained. Animals in the 3 treatment groups, designated with the letter "a", were administered MP, 1 mg/kg/d, whereas those in control groups "b" received 1 mL normal saline, both during 3 weeks. All subjects were followed up for 2 months. At the end of this period, all animals had the buccal branch of the facial nerve excised on the operated side. Semi-thin sections of these specimens were evaluated under light microscopy for the following: perineural fibrosis, increase in collagen fibers, myelin degeneration, axonal degeneration, Schwann cell proliferation, and edema. No significant difference was observed (P > 0.05) between the MP treatment group and the control group with regard to perineural fibrosis, increase in collagen fibers, myelin degeneration, axonal degeneration, edema, or Schwann cell proliferation. In the group with a compressive lesion (Group 2), controls were no different from MP-treated animals as to perineural fibrosis, increase in collagen fibers, or Schwann cell proliferation, whereas axonal degeneration, myelin degeneration, and edema were significantly higher (P < 0.05) in the control group. When comparing the treatment and control groups among the animals inoculated with Type 1 HSV, no significant difference was found with regard to perineural fibrosis, axonal degeneration, myelin degeneration, or Schwann cell proliferation. The only statistically significant advantage of the treatment group was in edema formation (P < 0.05). As a result of the evaluation of MP efficacy in different models of facial nerve palsy, we may say that this drug was without effect on nerve healing in paralysis due to nerve section and that it only reduced nervous edema in paralysis induced by Type 1 HSV, whereas it had positive effects on healing in the type of paralysis caused by nerve compression.

Electromagnetic backscattering from one-dimensional drifting fractal sea surface II: Electromagnetic backscattering model

NASA Astrophysics Data System (ADS)

Tao, Xie; William, Perrie; Shang-Zhuo, Zhao; He, Fang; Wen-Jin, Yu; Yi-Jun, He

2016-07-01

Sea surface current has a significant influence on electromagnetic (EM) backscattering signals and may constitute a dominant synthetic aperture radar (SAR) imaging mechanism. An effective EM backscattering model for a one-dimensional drifting fractal sea surface is presented in this paper. This model is used to simulate EM backscattering signals from the drifting sea surface. Numerical results show that ocean currents have a significant influence on EM backscattering signals from the sea surface. The normalized radar cross section (NRCS) discrepancies between the model for a coupled wave-current fractal sea surface and the model for an uncoupled fractal sea surface increase with the increase of incidence angle, as well as with increasing ocean currents. Ocean currents that are parallel to the direction of the wave can weaken the EM backscattering signal intensity, while the EM backscattering signal is intensified by ocean currents propagating oppositely to the wave direction. The model presented in this paper can be used to study the SAR imaging mechanism for a drifting sea surface. Project supported by the National Natural Science Foundation of China (Grant No. 41276187), the Global Change Research Program of China (Grant No. 2015CB953901), the Priority Academic Program Development of Jiangsu Higher Education Institutions, China, the Program for the Innovation Research and Entrepreneurship Team in Jiangsu Province, China, the Canadian Program on Energy Research and Development, and the Canadian World Class Tanker Safety Service Program.

Analysis and testing of axial compression in imperfect slender truss struts

NASA Technical Reports Server (NTRS)

Lake, Mark S.; Georgiadis, Nicholas

1990-01-01

The axial compression of imperfect slender struts for large space structures is addressed. The load-shortening behavior of struts with initially imperfect shapes and eccentric compressive end loading is analyzed using linear beam-column theory and results are compared with geometrically nonlinear solutions to determine the applicability of linear analysis. A set of developmental aluminum clad graphite/epoxy struts sized for application to the Space Station Freedom truss are measured to determine their initial imperfection magnitude, load eccentricity, and cross sectional area and moment of inertia. Load-shortening curves are determined from axial compression tests of these specimens and are correlated with theoretical curves generated using linear analysis.

Compressibility of porous TiO2 nanoparticle coating on paperboard

PubMed Central

2013-01-01

Compressibility of liquid flame spray-deposited porous TiO2 nanoparticle coating was studied on paperboard samples using a traditional calendering technique in which the paperboard is compressed between a metal and polymer roll. Surface superhydrophobicity is lost due to a smoothening effect when the number of successive calendering cycles is increased. Field emission scanning electron microscope surface and cross‒sectional images support the atomic force microscope roughness analysis that shows a significant compressibility of the deposited TiO2 nanoparticle coating with decrease in the surface roughness and nanoscale porosity under external pressure. PACS 61.46.-w; 68.08.Bc; 81.07.-b PMID:24160373

Comparative Study of Drift Compensation Methods for Environmental Gas Sensors

NASA Astrophysics Data System (ADS)

Abidin, M. Z.; Asmat, Arnis; Hamidon, M. N.

2018-02-01

Most drift compensation attempts in environmental gas sensors are only emphasize on the “already-known” drift-causing parameter (i.e., ambient temperature, relative humidity) in compensating the sensor drift. Less consideration is taken to another parameter (i.e., baseline responses) that might have affected indirectly with the promotion of drift-causing parameter variable (in this context, is ambient temperature variable). In this study, the “indirect” drift-causing parameter (drifted baseline responses) has been taken into consideration in compensating the sensor drift caused by ambient temperature variable, by means of a proposed drift compensation method (named as RT-method). The effectiveness of this method in its efficacy of compensating drift was analysed and compared with the common method that used the “already-known” drift-causing parameter (named as T-method), using drift reduction percentage. From the results analysis, the RT-method has outperformed T- method in the drift reduction percentage, with its ability to reduce drift up to 64% rather than the T-method which only able to reduce up to 45% for TGS2600 sensor. It has proven that the inclusion of drifted baseline responses into drift compensation attempt would resulted to an improved drift compensation efficiency.

Beam dynamics performances and applications of a low-energy electron-beam magnetic bunch compressor

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

Prokop, C. R.; Piot, P.; Carlsten, B. E.

2013-08-01

Many front-end applications of electron linear accelerators rely on the production of temporally compressed bunches. The shortening of electron bunches is often realized with magnetic bunch compressors located in high-energy sections of accelerators. Magnetic compression is subject to collective effects including space charge and self interaction via coherent synchrotron radiation. In this paper we explore the application of magnetic compression to low-energy (~40MeV), high-charge (nC) electron bunches with low normalized transverse emittances (<5@mm).

Damage development under compression-compression fatigue loading in a stitched uniwoven graphite/epoxy composite material

NASA Technical Reports Server (NTRS)

Vandermey, Nancy E.; Morris, Don H.; Masters, John E.

1991-01-01

Damage initiation and growth under compression-compression fatigue loading were investigated for a stitched uniweave material system with an underlying AS4/3501-6 quasi-isotropic layup. Performance of unnotched specimens having stitch rows at either 0 degree or 90 degrees to the loading direction was compared. Special attention was given to the effects of stitching related manufacturing defects. Damage evaluation techniques included edge replication, stiffness monitoring, x-ray radiography, residual compressive strength, and laminate sectioning. It was found that the manufacturing defect of inclined stitches had the greatest adverse effect on material performance. Zero degree and 90 degree specimen performances were generally the same. While the stitches were the source of damage initiation, they also slowed damage propagation both along the length and across the width and affected through-the-thickness damage growth. A pinched layer zone formed by the stitches particularly affected damage initiation and growth. The compressive failure mode was transverse shear for all specimens, both in static compression and fatigue cycling effects.

An efficient incremental learning mechanism for tracking concept drift in spam filtering

PubMed Central

Sheu, Jyh-Jian; Chu, Ko-Tsung; Li, Nien-Feng; Lee, Cheng-Chi

2017-01-01

This research manages in-depth analysis on the knowledge about spams and expects to propose an efficient spam filtering method with the ability of adapting to the dynamic environment. We focus on the analysis of email’s header and apply decision tree data mining technique to look for the association rules about spams. Then, we propose an efficient systematic filtering method based on these association rules. Our systematic method has the following major advantages: (1) Checking only the header sections of emails, which is different from those spam filtering methods at present that have to analyze fully the email’s content. Meanwhile, the email filtering accuracy is expected to be enhanced. (2) Regarding the solution to the problem of concept drift, we propose a window-based technique to estimate for the condition of concept drift for each unknown email, which will help our filtering method in recognizing the occurrence of spam. (3) We propose an incremental learning mechanism for our filtering method to strengthen the ability of adapting to the dynamic environment. PMID:28182691

[Caesarean section with vacuum extraction of the head].

PubMed

Dimitrov, A; Pavlova, E; Krŭsteva, K; Nikolov, A

2008-01-01

The aim of the study is to investigate the benefits and the limits in using the soft cup vacuum extractor on the fetal scalp during the caesarean section. The prospective study includes 19 cases of caesarean sections (group A), with vacuum assisted delivery using the soft cup vacuum extractor on the fetal scalp (diameter 6 cm) and 25 cases (group B) of caesarean sections with usual, manual extraction of the head assisted by fundal compression. All of the patients had undergone a planned caesarean section on term in absence of uterine activity and preserved amniotic membranes. Our results doesn't show differences in the Apgar score on the first and 5-th minute in the newborns of the two groups. The duration of the scalp traction was significantly shorter (30 +/- 4 sec) in comparison to the classical manual extraction (53 +/- 21 sec). The mean duration for applying the vacuum cup was 10 sec and 25 sec for tractions. The total blood loose and total duration of the caesarean sections were shorter than in the control group. The applied traction with the vacuum cup was sufficient for head extraction and there was no need for additional fundal compression. In conclusion we consider that the extraction of the fetal head in high position in caesarean section with vacuum extractor is an easy, non traumatic and rapid method which can put away the need of rough and prolonged fundal compression and its consequences.

Remote sensing revealed drainage anomalies and related tectonics of South India

NASA Astrophysics Data System (ADS)

Ramasamy, SM.; Kumanan, C. J.; Selvakumar, R.; Saravanavel, J.

2011-03-01

Drainages have characteristic pattern and life histories with youthful stage in hilly areas, mature stage in plains and old stage in the coastal zones. The deviations from their normal life histories, especially aberrations in their flow pattern in the form of various drainage anomalies have been inferred to be the indications of dominantly the Eustatic and Isostatic changes. This, especially after the advent of Earth Observing Satellites, has attracted the geoscientists from all over the world, for studying such drainage anomalies. In this connection, a study has been undertaken in parts of South India falling south of 14° south latitude to comprehensively map some drainage anomalies like deflected drainages, eyed drainages and compressed meanders and to evolve the tectonic scenario therefrom. The mapping of such mega drainage anomalies and the related lineaments/faults from the satellite digital data and the integration of such lineaments/faults with the overall lineament map of South India showed that the study area is marked by active N-S block faults and NE-SW sinistral and NW-SE dextral strike slip faults. Such an architecture of active tectonic grains indicates that the northerly directed compressive force which has originally drifted the Indian plate towards northerly is still active and deforming the Indian plate.

Studies of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources

NASA Astrophysics Data System (ADS)

Stepanov, A.; Gilson, E. P.; Grisham, L.; Davidson, R. C.

2013-10-01

Space-charge forces limit the possible transverse compression of high perveance ion beams that are used in ion-beam-driven high energy density physics applications; the minimum radius to which a beam can be focused is an increasing function of perveance. The limit can be overcome if a plasma is introduced in the beam path between the focusing element and the target in order to neutralize the space charge of the beam. This concept has been implemented on the Neutralized Drift Compression eXperiment (NDCX) at LBNL using Ferroelectric Plasma Sources (FEPS). In our experiment at PPPL, we propagate a perveance-dominated ion beam through a FEPS to study the effect of the neutralizing plasma on the beam envelope and its evolution in time. A 30-60 keV space-charge-dominated Argon beam is focused with an Einzel lens into a FEPS located at the beam waist. The beam is intercepted downstream from the FEPS by a movable Faraday cup that provides time-resolved 2D current density profiles of the beam spot on target. We report results on: (a) dependence of charge neutralization on FEPS plasma density; (b) effects on beam emittance, and (c) time evolution of the beam envelope after the FEPS pulse. Research supported by the U.S. Department of Energy.

Swim stress, motion, and deformation of active matter: effect of an external field.

PubMed

Takatori, Sho C; Brady, John F

2014-12-21

We analyze the stress, dispersion, and average swimming speed of self-propelled particles subjected to an external field that affects their orientation and speed. The swimming trajectory is governed by a competition between the orienting influence (i.e., taxis) associated with the external (e.g., magnetic, gravitational, thermal, nutrient concentration) field versus the effects that randomize the particle orientations (e.g., rotary Brownian motion and/or an intrinsic tumbling mechanism like the flagella of bacteria). The swimmers' motion is characterized by a mean drift velocity and an effective translational diffusivity that becomes anisotropic in the presence of the orienting field. Since the diffusivity yields information about the micromechanical stress, the anisotropy generated by the external field creates a normal stress difference in the recently developed "swim stress" tensor [Takatori, Yan, and Brady, Phys. Rev. Lett., 2014]. This property can be exploited in the design of soft, compressible materials in which their size, shape, and motion can be manipulated and tuned by loading the material with active swimmers. Since the swimmers exert different normal stresses in different directions, the material can compress/expand, elongate, and translate depending on the external field strength. Such an active system can be used as nano/micromechanical devices and motors. Analytical solutions are corroborated by Brownian dynamics simulations.

Risk assessment of brine contamination to aquatic resources from energy development in glacial drift deposits: Williston Basin, USA

USGS Publications Warehouse

Preston, Todd M.; Chesley-Preston, Tara

2015-01-01

Our goal was to improve the Sheridan County assessment (SCA) and evaluate the use of this new Williston Basin assessment (WBA) across 31 counties mantled by glacial drift in the Williston Basin. To determine if the WBA model improved the SCA model, results from both assessments were compared to CI values from 37 surface and groundwater samples collected to evaluate the SCA. The WBA (R2 = 0.65) outperformed the SCA (R2 = 0.52) indicating improved model performance. Applicability across the Williston Basin was evaluated by comparing WBA results to CI values from 123 surface water samples collected from 97 sections. Based on the WBA, the majority (83.5%) of sections lacked an oil well and had minimal risk. Sections with one or more oil wells comprised low (8.4%), moderate (6.5%), or high (1.7%) risk areas. The percentage of contaminated water samples, percentage of sections with at least one contaminated sample, and the average CI value of contaminated samples increased from low to high risk indicating applicability across the Williston Basin. Furthermore, the WBA performed better compared to only the contaminated samples (R2 = 0.62) versus all samples (R2 = 0.38). This demonstrates that the WBA was successful at identifying sections, but not individual aquatic resources, with an increased risk of contamination; therefore, WBA results can prioritize future sampling within areas of increased risk.

High Temperature - Thin Film Strain Gages Based on Alloys of Indium Tin Oxide

NASA Technical Reports Server (NTRS)

Gregory, Otto J.; Cooke, James D.; Bienkiewicz, Joseph M.

1998-01-01

A stable, high temperature strain gage based on reactively sputtered indium tin oxide (ITO) was demonstrated at temperatures up to 1050 C. These strain sensors exhibited relatively large, negative gage factors at room temperature and their piezoresistive response was both linear and reproducible when strained up to 700 micro-in/in. When cycled between compression and tension, these sensors also showed very little hysteresis, indicating excellent mechanical stability. Thin film strain gages based on selected ITO alloys withstood more than 50,000 strain cycles of +/- 500 micro-in/in during 180 hours of testing in air at 1000 C, with minimal drift at temperature. Drift rates as low as 0.0009%/hr at 1000 C were observed for ITO films that were annealed in nitrogen at 700 C prior to strain testing. These results compare favorably with state of the art 10 micro-m thick PdCr films deposited by NASA, where drift rates of 0.047%/hr at 1050 C were observed. Nitrogen annealing not only produced the lowest drift rates to date, but also produce the largest dynamic gage factors (G = 23.5). These wide bandgap, semiconductor strain sensors also exhibited moderately low temperature coefficients of resistance (TCR) at temperatures up to 1100 C, when tested in a nitrogen ambient. A TCR of +230 ppm/C over the temperature range 200 C < T < 500 C and a TCR of -469 ppm/C over the temperature range 600 C < T < 1100 C was observed for the films tested in nitrogen. However, the resistivity behavior changed considerably when the same films were tested in oxygen ambients. A TCR of -1560 ppm/C was obtained over the temperature range of 200 C < T < 1100 C. When similar films were protected with an overcoat or when ITO films were prepared with higher oxygen contents in the plasma, two distinct TCR's were observed. At T < 800 C, a linear TCR of -210 ppm/C was observed and at T > 800 C, a linear TCR of -2170 DDm/C was observed. The combination of a moderately low TCR and a relatively large gage factor make these semiconducting oxide films promising candidates for the active strain elements in high temperature thin film strain gages, particularly in applications where static strain measurement is desired.

Multiscale Observation System for Sea Ice Drift and Deformation

NASA Astrophysics Data System (ADS)

Lensu, M.; Haapala, J. J.; Heiler, I.; Karvonen, J.; Suominen, M.

2011-12-01

The drift and deformation of sea ice cover is most commonly followed from successive SAR images. The time interval between the images is seldom less than one day which provides rather crude approximation of the motion fields as ice can move tens of kilometers per day. This is particulary so from the viewpoint of operative services, seeking to provide real time information for ice navigating ships and other end users, as leads are closed and opened or ridge fields created in time scales of one hour or less. The ice forecast models are in a need of better temporal resolution for ice motion data as well. We present experiences from a multiscale monitoring system set up to the Bay of Bothnia, the northernmost basin of the Baltic Sea. The basin generates difficult ice conditions every winter while the ports are kept open with the help of an icebreaker fleet. The key addition to SAR imagery is the use of coastal radars for the monitoring of coastal ice fields. An independent server is used to tap the radar signal and process it to suit ice monitoring purposes. This is done without interfering the basic use of the radars, the ship traffic monitoring. About 20 images per minute are captured and sent to the headquarters for motion field extraction, website animation and distribution. This provides very detailed real time picture of the ice movement and deformation within 20 km range. The real time movements are followed in addition with ice drifter arrays, and using AIS ship identification data, from which the translation of ship cannels due to ice drift can be found out. To the operative setup is associated an extensive research effort that uses the data for ice drift model enhancement. The Baltic ice models seek to forecast conditions relevant to ship traffic, especilly hazardous ones like severe ice compression. The main missing link here is downscaling, or the relation of local scale ice dynamics and kinematics to the ice model scale behaviour. The data flow when combined with SAR images gives information on how large scale ice cover motions manifest as local scale deformations. The research includes also ice stress measurements for relating the kinematic state and modeled stresses to local scale ice cover stresses, and ice thickness mappings with profiling sonars and EM methods. Downscaling results based on four-month campaing during winter 2011 are presented.

Effects of an Experimental Enrichment of Instream Habitat Heterogeneity on the Stream Bed Morphology and Chironomid Community of a Straightened Section in a Sandy Lowland Stream

NASA Astrophysics Data System (ADS)

Spänhoff, Bernd; Riss, Wolfgang; Jäkel, Paul; Dakkak, Nadja; Meyer, Elisabeth I.

2006-02-01

A straightened stream stretch with poor habitat heterogeneity was divided into a “control” section with a low amount of submerged woody debris and an experimentally “wood-enriched” downstream section to study the effect of enhanced habitat diversity on the benthic invertebrate community. The downstream section was enriched by fixing 25 wood packages constructed from 9-10 branches on the stream bottom. Succession processes occurring in the two stream sections were compared by chironomid exuviae drift from July to November 2000 and from April to August 2001. During the first sampling period, more drifting chironomid exuviae (medians of control vs. wood-enriched: 446 vs. 331, no significant difference) and total number of taxa (44 vs. 36, Wilcoxon signed-rank test P = 0.019) were recorded for the control section. Although species compositions of both stream sections were highly similar (Sørensen index: 0.83) the diversity in the wood-enriched section was distinctly lower compared to the control section (Shannon-Weaver index: 1.19 vs. 1.50). During the second sampling period, exuviae numbers remained higher in the control section (median: 326 vs. 166), but total numbers of taxa were nearly equal (51 vs. 49), as well as species diversity (Shannon-Weaver index: 1.67 vs. 1.64). The lower chironomid diversity observed during the first sampling period coincided with a gradual but significant change of the streambed morphology in the wood-enriched section. There, the initially more U-shaped profile (V/U = 0.81 ± 0.37) had turned into a pronounced V shape (V/U = 1.14 ± 0.21), whereas the control section retained its unaltered U shape (V/U = 0.62-0.75). This small-scale study on experimental of woody debris in sandy lowland streams showed that the negative impact of increased hydraulic disturbance of the existing streambed more than outweighed any positive impact resulting from the increase in woody debris.

Collision cross sections of high-mannose N-glycans in commonly observed adduct states--identification of gas-phase conformers unique to [M-H](-) ions.

PubMed

Struwe, W B; Benesch, J L; Harvey, D J; Pagel, K

2015-10-21

We report collision cross sections (CCS) of high-mannose N-glycans as [M + Na](+), [M + K](+), [M + H](+), [M + Cl](-), [M + H2PO4](-) and [M - H](-) ions, measured by drift tube (DT) ion mobility-mass spectrometry (IM-MS) in helium and nitrogen gases. Further analysis using traveling wave (TW) IM-MS reveal the existence of distinct conformers exclusive to [M - H](-) ions.

Data compression experiments with LANDSAT thematic mapper and Nimbus-7 coastal zone color scanner data

NASA Technical Reports Server (NTRS)

Tilton, James C.; Ramapriyan, H. K.

1989-01-01

A case study is presented where an image segmentation based compression technique is applied to LANDSAT Thematic Mapper (TM) and Nimbus-7 Coastal Zone Color Scanner (CZCS) data. The compression technique, called Spatially Constrained Clustering (SCC), can be regarded as an adaptive vector quantization approach. The SCC can be applied to either single or multiple spectral bands of image data. The segmented image resulting from SCC is encoded in small rectangular blocks, with the codebook varying from block to block. Lossless compression potential (LDP) of sample TM and CZCS images are evaluated. For the TM test image, the LCP is 2.79. For the CZCS test image the LCP is 1.89, even though when only a cloud-free section of the image is considered the LCP increases to 3.48. Examples of compressed images are shown at several compression ratios ranging from 4 to 15. In the case of TM data, the compressed data are classified using the Bayes' classifier. The results show an improvement in the similarity between the classification results and ground truth when compressed data are used, thus showing that compression is, in fact, a useful first step in the analysis.

Reducing Pesticide Drift

EPA Pesticide Factsheets

Provides information about pesticide spray drift, including problems associated with drift, managing risks from drift and the voluntary Drift Reduction Technology program that seeks to reduce spray drift through improved spray equipment design.

A Selected Annotated Bibliography on Work Time Options.

ERIC Educational Resources Information Center

Ivantcho, Barbara

This annotated bibliography is divided into three sections. Section I contains annotations of general publications on work time options. Section II presents resources on flexitime and the compressed work week. In Section III are found resources related to these reduced work time options: permanent part-time employment, job sharing, voluntary…

49 CFR 173.315 - Compressed gases in cargo tanks and portable tanks.

Code of Federal Regulations, 2010 CFR

2010-10-01

... liquefied petroleum gas are as follows: Maximum specific gravity of the liquid material at 60 °F. Maximum... 49 Transportation 2 2010-10-01 2010-10-01 false Compressed gases in cargo tanks and portable tanks. 173.315 Section 173.315 Transportation Other Regulations Relating to Transportation PIPELINE AND...

30 CFR 77.411 - Compressed air and boilers; general.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Compressed air and boilers; general. 77.411 Section 77.411 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment ...

30 CFR 77.411 - Compressed air and boilers; general.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Compressed air and boilers; general. 77.411 Section 77.411 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment ...

30 CFR 77.411 - Compressed air and boilers; general.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Compressed air and boilers; general. 77.411 Section 77.411 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment ...

30 CFR 77.411 - Compressed air and boilers; general.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Compressed air and boilers; general. 77.411 Section 77.411 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment ...

30 CFR 77.411 - Compressed air and boilers; general.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compressed air and boilers; general. 77.411 Section 77.411 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment ...

41 CFR 50-204.67 - Oxygen.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Oxygen. 50-204.67 Section..., Vapors, Fumes, Dusts, and Mists § 50-204.67 Oxygen. The in-plant transfer, handling, storage, and utilization of oxygen as a liquid or a compressed gas shall be in accordance with Compressed Gas Association...

41 CFR 50-204.67 - Oxygen.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Oxygen. 50-204.67 Section..., Vapors, Fumes, Dusts, and Mists § 50-204.67 Oxygen. The in-plant transfer, handling, storage, and utilization of oxygen as a liquid or a compressed gas shall be in accordance with Compressed Gas Association...

41 CFR 50-204.67 - Oxygen.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 41 Public Contracts and Property Management 1 2011-07-01 2009-07-01 true Oxygen. 50-204.67 Section..., Vapors, Fumes, Dusts, and Mists § 50-204.67 Oxygen. The in-plant transfer, handling, storage, and utilization of oxygen as a liquid or a compressed gas shall be in accordance with Compressed Gas Association...

49 CFR 393.68 - Compressed natural gas fuel containers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... containers. (a) Applicability. The rules in this section apply to compressed natural gas (CNG) fuel... auxiliary equipment installed on, or used in connection with commercial motor vehicles. (b) CNG containers... equipped with a CNG fuel tank must meet the CNG container requirements of FMVSS No. 304 (49 CFR 571.304) in...

49 CFR 393.68 - Compressed natural gas fuel containers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... containers. (a) Applicability. The rules in this section apply to compressed natural gas (CNG) fuel... auxiliary equipment installed on, or used in connection with commercial motor vehicles. (b) CNG containers... equipped with a CNG fuel tank must meet the CNG container requirements of FMVSS No. 304 (49 CFR 571.304) in...

49 CFR 393.68 - Compressed natural gas fuel containers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... containers. (a) Applicability. The rules in this section apply to compressed natural gas (CNG) fuel... auxiliary equipment installed on, or used in connection with commercial motor vehicles. (b) CNG containers... equipped with a CNG fuel tank must meet the CNG container requirements of FMVSS No. 304 (49 CFR 571.304) in...

49 CFR 571.303 - Standard No. 303; Fuel system integrity of compressed natural gas vehicles.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 6 2013-10-01 2013-10-01 false Standard No. 303; Fuel system integrity of compressed natural gas vehicles. 571.303 Section 571.303 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION FEDERAL MOTOR VEHICLE SAFETY STANDARDS Federal...

Determination of stresses in RC eccentrically compressed members using optimization methods

NASA Astrophysics Data System (ADS)

Lechman, Marek; Stachurski, Andrzej

2018-01-01

The paper presents an optimization method for determining the strains and stresses in reinforced concrete (RC) members subjected to the eccentric compression. The governing equations for strains in the rectangular cross-sections are derived by integrating the equilibrium equations of cross-sections, taking account of the effect of concrete softening in plastic range and the mean compressive strength of concrete. The stress-strain relationship for concrete in compression for short term uniaxial loading is assumed according to Eurocode 2 for nonlinear analysis. For reinforcing steel linear-elastic model with hardening in plastic range is applied. The task consists in the solving the set of the derived equations s.t. box constraints. The resulting problem was solved by means of fmincon function implemented from the Matlab's Optimization Toolbox. Numerical experiments have shown the existence of many points verifying the equations with a very good accuracy. Therefore, some operations from the global optimization were included: start of fmincon from many points and clusterization. The model is verified on the set of data encountered in the engineering practice.

Compression of Encrypted Images Using Set Partitioning In Hierarchical Trees Algorithm

NASA Astrophysics Data System (ADS)

Sarika, G.; Unnithan, Harikuttan; Peter, Smitha

2011-10-01

When it is desired to transmit redundant data over an insecure channel, it is customary to encrypt the data. For encrypted real world sources such as images, the use of Markova properties in the slepian-wolf decoder does not work well for gray scale images. Here in this paper we propose a method of compression of an encrypted image. In the encoder section, the image is first encrypted and then it undergoes compression in resolution. The cipher function scrambles only the pixel values, but does not shuffle the pixel locations. After down sampling, each sub-image is encoded independently and the resulting syndrome bits are transmitted. The received image undergoes a joint decryption and decompression in the decoder section. By using the local statistics based on the image, it is recovered back. Here the decoder gets only lower resolution version of the image. In addition, this method provides only partial access to the current source at the decoder side, which improves the decoder's learning of the source statistics. The source dependency is exploited to improve the compression efficiency. This scheme provides better coding efficiency and less computational complexity.

A sequential compression mechanical pump to prevent hypotension during elective cesarean section under spinal anesthesia.

PubMed

Sujata, N; Arora, D; Panigrahi, B P; Hanjoora, V M

2012-04-01

Spinal anesthesia is a standard technique for cesarean section but can cause hypotension which may be related to venous pooling secondary to progesterone-induced decreases in vascular tone. This study investigated the use of a sequential compression mechanical pump with thigh-high sleeves with compression cycles timed to venous refilling. We hypothesized that this would recruit pooled venous blood from the lower limbs, maintain the central blood volume and thus decrease the incidence of hypotension. One hundred parturients scheduled for elective cesarean section under spinal anesthesia were recruited and randomly assigned to use of either a mechanical pump (Group M) or control (Group C). A standardized protocol for co-hydration and anesthesia was followed. Hypotension, defined as a decrease in systolic blood pressure by >20% from baseline, was treated with 6-mg boluses of intravenous ephedrine. The incidence of hypotension was defined as the primary outcome. Median ephedrine requirement was taken as a measure of the severity of hypotension. Hypotension occurred in 12 of 47 (25.5%) patients in Group M compared to 27 of 45 (60%) in Group C (P=0.001). The median [range] ephedrine dose was greater in Group C (12 [0-24]mg) compared to Group M (0 [0-12]mg) (P<0.001). There was no difference between groups in the time to onset of hypotension. The use of a sequential compression mechanical pump that detects venous refilling and cycles accordingly, reduced the incidence and severity of hypotension after spinal anesthesia for cesarean section. Copyright © 2012 Elsevier Ltd. All rights reserved.

Energization of Radiation Belt Electrons by High and Low Azimuthal Mode Number Poloidal Mode ULF Waves

NASA Astrophysics Data System (ADS)

Hudson, M. K.; Brito, T.; Elkington, S. R.; Kress, B. T.; Liang, Y.

2011-12-01

CME-shock and CIR-driven geomagnetic storms are characterized by enhanced ULF wave activity in the magnetosphere. This enhanced ULF wave power produces both coherent and diffusive transport and energization, as well as pitch angle modification of radiation belt electrons in drift resonance with azimuthally propagating ULF waves. Recent observations of two CME-driven storms1,2 have suggested that poloidal mode waves with both low and high azimuthal mode number may be efficient at accelerating radiation belt electrons. We extend up to m = 50 the analysis of Ozeke and Mann3 who examined drift resonance for poloidal modes up to m = 40. We calculate radial diffusion coefficients for source population electrons in the 50 -500 keV range, and continued resonance with lower m-numbers at higher energies for ULF waves in the Pc 5, 0.4 - 10 mHz range. We use an analytic model for ULF waves superimposed on a compressed dipole, developed for equatorial plane studies by Elkington et al.4 and extended to 3D by Perry et al.4 Assuming a power spectrum which varies as ω-2, consistent with earlier observations, we find greater efficiency for radial transport and acceleration at lower m number where there is greater power for drift resonance at a given frequency. This assumption is consistent with 3D global MHD simulations using the Lyon-Fedder-Mobarry code which we have carried out for realistic solar wind driving conditions during storms. Coherent interaction with ULF waves can also occur at a rate which exceeds nominal radial diffusion estimates but is slower than prompt injection on a drift time scale. Depending on initial electron drift phase, some electrons are accelerated due to the westward azimuthal electric field Eφ, while others are decelerated by eastward Eφ, decreasing their pitch angle. A subset of trapped electrons are seen to precipitate to the atmosphere in 3D LFM simulations, showing modulation at the coherent poloidal mode ULF wave frequency in both simulations and MINIS balloon observations for the January 21, 2005 CME-driven storm. Thus Pc 5 poloidal mode ULF waves cause competing increase and decrease in relativistic electron flux. The relative efficiencies of both coherent and diffusive processes will be examined. 1Zong et al., JGR, doi:10.1029/2009JA014393, 2009. 2Tan et al., JGR, doi:10.1029/2010JA016226, 2011. 3Ozeke and Mann, JGR, doi:10.1029/2007JA012468, 2008. 4Elkington et al., doi:10.1029/2001JA009202, 2003, 2003. 5Perry et al., doi:10.1029/2004JA010760, 2005.

6. West elevation of Drift Creek Bridge, view looking east ...

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

6. West elevation of Drift Creek Bridge, view looking east from new alignment of Drift Creek Road - Drift Creek Bridge, Spanning Drift Creek on Drift Creek County Road, Lincoln City, Lincoln County, OR

2- to 3-kHz continuum emissions as possible indications of global heliospheric 'breathing'

NASA Technical Reports Server (NTRS)

Grzedzielski, S.; Lazarus, A. J.

1993-01-01

The paper analyzes the main features of 2- to 3-kHz heliospheric emissions in the context of a general heliospheric 'breathing' as inferred from the Voyager 2 solar wind average ram pressure data. Triggers for the three 3-kHz emission events seen to date are suggested, and good agreement is obtained in timing and expected postshock frequency for termination shock distances of about 90 AU. It is suggested that the visibility of the individual 3-kHz events and their observed upward frequency drift are enhanced when the postulated global heliospheric expansion results in the formation of a transient, compressed external plasma barrier around the heliopause that prevents radiation escape for several months. The average termination shock distance is estimated to be in the range 80-90 AU.

Wave Telescope Technique for MMS Magnetometer

NASA Technical Reports Server (NTRS)

Narita, Y.; Plaschke, F.; Nakamura, R.; Baumjojann, W.; Magnes, W.; Fischer, D.; Voros, Z.; Torbert, R. B.; Russell, C. T.; Strangeway, R. J.;

Macroscopic strain controlled ion current in an elastomeric microchannel

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

Kuo, Chin-Chang; Nguyen, Du; Buchsbaum, Steven

We report on the fabrication of an ultra-high aspect ratio ionically conductive single microchannel with tunable diameter from ≈ 20 μm to fully closed. The 4 mm-long channel is fabricated in a Polydimethylsiloxane (PDMS) mold and its cross-sectional area is controlled by applying macroscopic compressive strain to the mold in a direction perpendicular to the channel length. We investigated the ionic conduction properties of the channel. For a wide range of compressive strain up to ≈ 0.27, the strain dependence of the resistance is monotonic and fully reversible. For strain > 0.27, ionic conduction suddenly shuts off and the system becomes hystereticmore » (whereby a finite strain reduction is required to reopen the channel). Upon unloading, the original behavior is retrieved. This reversible behavior is observed over 200 compression cycles. The cross-sectional area of the channel can be inferred from the ion current measurement, as confirmed by a Nano-Computed Tomography investigation. We show that the cross-sectional area decreases monotonically with the applied compressive strain in the reversible range, in qualitative agreement with linear elasticity theory. We find that the shut-off strain is affected by the spatial extent of the applied strain, which provides additional tunability. Our tunable channel is well-suited for multiple applications in micro/nano-fluidic devices.« less

Compressible viscous flows generated by oscillating flexible cylinders

NASA Astrophysics Data System (ADS)

Van Eysden, Cornelis A.; Sader, John E.

2009-01-01

The fluid dynamics of oscillating elastic beams underpin the operation of many modern technological devices ranging from micromechanical sensors to the atomic force microscope. While viscous effects are widely acknowledged to have a strong influence on these dynamics, fluid compressibility is commonly neglected. Here, we theoretically study the three-dimensional flow fields that are generated by the motion of flexible cylinders immersed in viscous compressible fluids and discuss the implications of compressibility in practice. We consider cylinders of circular cross section and flat blades of zero thickness that are executing flexural and torsional oscillations of arbitrary wave number. Exact analytical solutions are derived for these flow fields and their resulting hydrodynamic loads.

Hydrogeology of the stratified-drift aquifers in the Cayuta Creek and Catatonk Creek valleys in parts of Tompkins, Schuyler, Chemung, and Tioga Counties, New York

USGS Publications Warehouse

Miller, Todd S.; Pitman, Lacey M.

2012-01-01

The surficial deposits, areal extent of aquifers, and the water-table configurations of the stratified-drift aquifer systems in the Cayuta Creek and Catatonk Creek valleys and their large tributary valleys in Tompkins, Schuyler, Chemung, and Tioga Counties, New York were mapped in 2009, in cooperation with the New York State Department of Environmental Conservation. Well and test-boring records, surficial deposit maps, Light Detection and Ranging (LIDAR) data, soils maps, and horizontal-to-vertical ambient-noise seismic surveys were used to map the extent of the aquifers, construct geologic sections, and determine the depth to bedrock (thickness of valley-fill deposits) at selected locations. Geologic materials in the study area include sedimentary bedrock, unstratified drift (till), stratified drift (glaciolacustrine and glaciofluvial deposits), and recent alluvium. Stratified drift consisting of glaciofluvial sand and gravel is the major component of the valley fill in this study area. The deposits are present in sufficient amounts in most places to form extensive unconfined aquifers throughout the study area and, in some places, confined aquifers. Stratified drift consisting of glaciolacustrine fine sand, silt, and clay are present locally in valleys underlying the surficial sand and gravel deposits in the southern part of the Catatonk Creek valley. These unconfined and confined aquifers are the source of water for most residents, farms, and businesses in the valleys. A generalized depiction of the water table in the unconfined aquifer was constructed using water-level measurements made from the 1950s through 2010, as well as LIDAR data that were used to determine the altitudes of perennial streams at 10-foot contour intervals and water surfaces of ponds and wetlands that are hydraulically connected to the unconfined aquifer. The configuration of the water-table contours indicate that the general direction of groundwater flow within Cayuta Creek and Catatonk Creek stratified-drift aquifers is predominantly from the valley walls toward the main streams in the valleys. The groundwater discharges from the aquifer system to the main-stem streams in the valleys. Locally, the direction of groundwater flow is radially away from groundwater mounds that have formed beneath upland tributaries that typically lose water where they flow on alluvial fans in the valleys. In some places, groundwater that would normally flow toward streams is intercepted by pumping wells.

40 CFR 63.1350 - Monitoring requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... zero and 1.5 times the average temperature established according to the requirements in § 63.1349(b)(3... absolute PM loadings. (v) The BLDS must be equipped with a device to continuously record the output signal... must have provisions to determine the daily zero and upscale calibration drift (CD) (see sections 3.1...

40 CFR 63.1350 - Monitoring requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... zero and 1.5 times the average temperature established according to the requirements in § 63.1349(b)(3... absolute PM loadings. (v) The BLDS must be equipped with a device to continuously record the output signal... must have provisions to determine the daily zero and upscale calibration drift (CD) (see sections 3.1...

Method and apparatus for ion mobility spectrometry with alignment of dipole direction (IMS-ADD)

DOEpatents

Shvartsburg, Alexandre A [Richland, WA; Tang, Keqi [Richland, WA; Smith, Richard D [Richland, WA

2007-01-30

Techniques and instrumentation are described for analyses of substances, including complex samples/mixtures that require separation prior to characterization of individual components. A method is disclosed for separation of ion mixtures and identification of ions, including protein and other macromolecular ions and their different structural isomers. Analyte ions are not free to rotate during the separation, but are substantially oriented with respect to the drift direction. Alignment is achieved by applying, at a particular angle to the drift field, a much stronger alternating electric field that "locks" the ion dipoles with moments exceeding a certain value. That value depends on the buffer gas composition, pressure, and temperature, but may be as low as .about.3 Debye under certain conditions. The presently disclosed method measures the direction-specific cross-sections that provide the structural information complementing that obtained from known methods, and, when coupled to those methods, increases the total peak capacity and specificity of gas-phase separations. Simultaneous 2-D separations by direction-specific cross sections along and orthogonally to the ion dipole direction are also possible.

PDF methods for combustion in high-speed turbulent flows

NASA Technical Reports Server (NTRS)

Pope, Stephen B.

1995-01-01

This report describes the research performed during the second year of this three-year project. The ultimate objective of the project is extend the applicability of probability density function (pdf) methods from incompressible to compressible turbulent reactive flows. As described in subsequent sections, progress has been made on: (1) formulation and modelling of pdf equations for compressible turbulence, in both homogeneous and inhomogeneous inert flows; and (2) implementation of the compressible model in various flow configurations, namely decaying isotropic turbulence, homogeneous shear flow and plane mixing layer.

Cooling system with compressor bleed and ambient air for gas turbine engine

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

Marsh, Jan H.; Marra, John J.

A cooling system for a turbine engine for directing cooling fluids from a compressor to a turbine blade cooling fluid supply and from an ambient air source to the turbine blade cooling fluid supply to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The cooling system may include a compressor bleed conduit extending from a compressor to the turbine blade cooling fluid supply that provides cooling fluid to at least one turbine blade. The compressor bleed conduit may include an upstream section and a downstream section whereby the upstream section exhausts compressed bleed airmore » through an outlet into the downstream section through which ambient air passes. The outlet of the upstream section may be generally aligned with a flow of ambient air flowing in the downstream section. As such, the compressed air increases the flow of ambient air to the turbine blade cooling fluid supply.« less

Amnioinfusion for umbilical cord compression in labour.

PubMed

Hofmeyr, G J

2000-01-01

Amnioinfusion aims to prevent or relieve umbilical cord compression during labour by infusing a solution into the uterine cavity. The objective of this review was to assess the effects of amnioinfusion on maternal and perinatal outcome for potential or suspected umbilical cord compression or potential amnionitis. The Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register were searched. Randomised trials of amnioinfusion compared with no amnioinfusion in women with babies at risk of umbilical cord compression; and women at risk of intrauterine infection. Eligibility and trial quality were assessed by the reviewer. Twelve studies were included. Transcervical amnioinfusion for potential or suspected umbilical cord compression was associated with the following reductions: fetal heart rate decelerations (relative risk 0.54, 95% confidence interval 0.43 to 0.68); caesarean section for suspected fetal distress (relative risk 0.35, 95% confidence interval 0.24 to 0.52); neonatal hospital stay greater than 3 days (relative risk 0.40, 95% confidence interval 0. 26 to 0.62); maternal hospital stay greater than 3 days (relative risk 0.46, 95% 0.29 to 0.74). Transabdominal amnioinfusion showed similar results. Transcervical amnioinfusion to prevent infection in women with membranes ruptured for more than 6 hours was associated with a reduction in puerperal infection (relative risk 0.50, 95% confidence interval 0.26 to 0.97). Amnioinfusion appears to reduce the occurrence of variable heart rate decelerations and lower the use of caesarean section. However the studies were done in settings where fetal distress was not confirmed by fetal blood sampling. The results may therefore only be relevant where caesarean sections are commonly done for abnormal fetal heart rate alone. The trials reviewed are too small to address the possibility of rare but serious maternal adverse effects of amnioinfusion.

40 CFR 600.306-12 - Fuel economy label-special requirements for compressed natural gas vehicles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Fuel economy label-special requirements for compressed natural gas vehicles. 600.306-12 Section 600.306-12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy Labeling §...

40 CFR 600.306-12 - Fuel economy label-special requirements for compressed natural gas vehicles.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Fuel economy label-special requirements for compressed natural gas vehicles. 600.306-12 Section 600.306-12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy Labeling §...

40 CFR 600.306-12 - Fuel economy label-special requirements for compressed natural gas vehicles.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Fuel economy label-special requirements for compressed natural gas vehicles. 600.306-12 Section 600.306-12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy Labeling §...

49 CFR 173.302a - Additional requirements for shipment of nonliquefied (permanent) compressed gases in...

Code of Federal Regulations, 2013 CFR

2013-10-01

... carbon monoxide. DOT 3T cylinders are not authorized for hydrogen. When used in methane service, the methane must be a nonliquefied gas with a minimum purity of 98.0 percent methane and commercially free of... nonliquefied (permanent) compressed gases in specification cylinders. 173.302a Section 173.302a Transportation...

49 CFR 173.302a - Additional requirements for shipment of nonliquefied (permanent) compressed gases in...

Code of Federal Regulations, 2014 CFR

2014-10-01

... carbon monoxide. DOT 3T cylinders are not authorized for hydrogen. When used in methane service, the methane must be a nonliquefied gas with a minimum purity of 98.0 percent methane and commercially free of... nonliquefied (permanent) compressed gases in specification cylinders. 173.302a Section 173.302a Transportation...

49 CFR 173.302a - Additional requirements for shipment of nonliquefied (permanent) compressed gases in...

Code of Federal Regulations, 2012 CFR

2012-10-01

... hydrogen. When used in methane service, the methane must be a nonliquefied gas with a minimum purity of 98... nonliquefied (permanent) compressed gases in specification cylinders. 173.302a Section 173.302a Transportation... PACKAGINGS Gases; Preparation and Packaging § 173.302a Additional requirements for shipment of nonliquefied...

A Storegga age turbidite at Eirik Drift, South Greenland: evidence for synchronous turbidite deposition at 8.2 ka BP in the North Atlantic?

NASA Astrophysics Data System (ADS)

Watts, Millie; Taylor, Vicki; Talling, Peter; Hunt, James; Stanford, Jennifer

2016-04-01

Eirik Drift contains a high-resolution record of climatic and oceanic variability. In addition, it records several submarine landslides throughout the Holocene. Submarine landslides and associated tsunamis are potentially damaging, and have the potential to travel significant distances across the North Atlantic. Two cores taken from Eirik Drift (D298-P2) show an expanded Holocene section of hemipelagite and contain a fine grained turbidite dated to 8.17 ka BP (+/- 200 years). This event is coincident with both the 8.2 ka BP climatic anomaly, and the Storegga Slide. Paleoenvironmental proxies suggest this 8.2 ka BP turbidite was deposited during the coldest part of the 8.2 ka BP event, interpreted here as a longer duration cooling. This Holocene Storegga Slide triggered a major tsunami, evidence of which has been found across Northern European coastlines and the East Greenland coast. Here we show that the 8.2 ka BP turbidite has a different provenance both to other turbidites within the D298 core, and the main body of the Storegga Slide turbidite, and is unique within the Eirik Drift sequence. We interpret this event within the core as a distal deposit of a turbidite transported within the Western boundary Under Current, potentially related to a more northerly Greenland impact of the Storegga Tsunami. The fine-grained nature of the deposit suggests significant transport, supporting the hypothesis this event relates to a Greenland impact of the Storegga Tsunami.

Erratum: Evidence That a Deep Meridional Flow Sets the Sunspot Cycle Period

NASA Technical Reports Server (NTRS)

Hathaway, David H.; Nandy, Dibyendu; Wilson, Robert M.; Reichmann, Edwin J.

2004-01-01

An error was made in entering the data. This changes the results concerning the length of the time lag between the variations in the meridional flow speed and those in the cycle amplitude. The final paragraph on page 667 should read: Finally, we study the relationship between the drift velocities and the amplitudes of the hemisphere/cycles. We compare the drift velocity at the maximum of the cycle to the amplitude of that cycle for that hemisphere. There is a positive (0.5) and significant (95%) correlation between the two. However, an even stronger relationship is found between the drift velocity and the amplitude of the N + 2 cycle. The correlation is stronger (0.7) and more significant (99%), as shown. This relationship is suggestive of a "memory" in the solar cycle, again a property of dynamo models that use meridional circulation. Indeed, the two-cycle lag is precisely the relationship found by Charbonneau & Dikpati. This behavior is, however, more difficult to interpret, and we elaborate on this in the next section. In either case, these correlations only explain part of the variance in cycle amplitude (25% for the current cycle and 50% for the N + 2 cycle). Obviously, other mechanisms, such as variations in the gradient in the rotation rate, also contribute to the cycle amplitude variations. Our investigation of possible connections between drift rates and the amplitudes of the N + 1 and N + 3 cycles gives no significant correlations at these alternative time lags.

Separation of glycosidic catiomers by TWIM-MS using CO2 as a drift gas.

PubMed

Bataglion, Giovana A; Souza, Gustavo Henrique Martins Ferreira; Heerdt, Gabriel; Morgon, Nelson H; Dutra, José Diogo Lisboa; Freire, Ricardo Oliveira; Eberlin, Marcos N; Tata, Alessandra

2015-02-01

Traveling wave ion mobility mass spectrometry (TWIM-MS) is shown to be able to separate and characterize several isomeric forms of diterpene glycosides stevioside (Stv) and rebaudioside A (RebA) that are cationized by Na(+) and K(+) at different sites. Determination and characterization of these coexisting isomeric species, herein termed catiomers, arising from cationization at different and highly competitive coordinating sites, is particularly challenging for glycosides. To achieve this goal, the advantage of using CO2 as a more massive and polarizable drift gas, over N2, was demonstrated. Post-TWIM-MS/MS experiments were used to confirm the separation. Optimization of the possible geometries and cross-sectional calculations for mobility peak assignments were also performed. Copyright © 2015 John Wiley & Sons, Ltd.

Methodology for the Design of Streamline-Traced External-Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Slater, John W.

2014-01-01

A design methodology based on streamline-tracing is discussed for the design of external-compression, supersonic inlets for flight below Mach 2.0. The methodology establishes a supersonic compression surface and capture cross-section by tracing streamlines through an axisymmetric Busemann flowfield. The compression system of shock and Mach waves is altered through modifications to the leading edge and shoulder of the compression surface. An external terminal shock is established to create subsonic flow which is diffused in the subsonic diffuser. The design methodology was implemented into the SUPIN inlet design tool. SUPIN uses specified design factors to design the inlets and computes the inlet performance, which includes the flow rates, total pressure recovery, and wave drag. A design study was conducted using SUPIN and the Wind-US computational fluid dynamics code to design and analyze the properties of two streamline-traced, external-compression (STEX) supersonic inlets for Mach 1.6 freestream conditions. The STEX inlets were compared to axisymmetric pitot, two-dimensional, and axisymmetric spike inlets. The STEX inlets had slightly lower total pressure recovery and higher levels of total pressure distortion than the axisymmetric spike inlet. The cowl wave drag coefficients of the STEX inlets were 20% of those for the axisymmetric spike inlet. The STEX inlets had external sound pressures that were 37% of those of the axisymmetric spike inlet, which may result in lower adverse sonic boom characteristics. The flexibility of the shape of the capture cross-section may result in benefits for the integration of STEX inlets with aircraft.

Corrections to the Thomson cross section caused by relativistic effects and by the presence of the drift velocity of a classical charged particle in the field of a monochromatic plane wave

NASA Astrophysics Data System (ADS)

Perestoronin, A. V.

2017-03-01

An approach to the solution of the relativistic problem of the motion of a classical charged particle in the field of a monochromatic plane wave with an arbitrary polarization (linear, circular, or elliptic) is proposed. It is based on the analysis of the 4-vector equation of motion of the charged particle together with the 4-vector and tensor equations for the components of the electromagnetic field tensor of a monochromatic plane wave. This approach provides analytical expressions for the time-averaged square of the 4-acceleration of the charge, as well as for the averaged values of any quantities periodic in the time of the reference frame. Expressions for the integral power of scattered radiation, which is proportional to the time-averaged square of the 4-acceleration of the charge, and for the integral scattering cross section, which is the ratio of the power of scattered radiation to the intensity of incident radiation, are obtained for an arbitrary inertial reference frame. An expression for the scattering cross section, which coincides with the known results at the circular and linear polarizations of the incident waves and describes the case of elliptic polarization of the incident wave, is obtained for the reference frame where the charged particle is on average at rest. An expression for the scattering cross section including relativistic effects and the nonzero drift velocity of a particle in this system is obtained for the laboratory reference frame, where the initial velocity of the charged particle is zero. In the case of the circular polarization of the incident wave, the scattering cross section in the laboratory frame is equal to the Thompson cross section.

Non-rigid alignment in electron tomography in materials science.

PubMed

Printemps, Tony; Bernier, Nicolas; Bleuet, Pierre; Mula, Guido; Hervé, Lionel

2016-09-01

Electron tomography is a key technique that enables the visualization of an object in three dimensions with a resolution of about a nanometre. High-quality 3D reconstruction is possible thanks to the latest compressed sensing algorithms and/or better alignment and preprocessing of the 2D projections. Rigid alignment of 2D projections is routine in electron tomography. However, it cannot correct misalignments induced by (i) deformations of the sample due to radiation damage or (ii) drifting of the sample during the acquisition of an image in scanning transmission electron microscope mode. In both cases, those misalignments can give rise to artefacts in the reconstruction. We propose a simple-to-implement non-rigid alignment technique to correct those artefacts. This technique is particularly suited for needle-shaped samples in materials science. It is initiated by a rigid alignment of the projections and it is then followed by several rigid alignments of different parts of the projections. Piecewise linear deformations are applied to each projection to force them to simultaneously satisfy the rigid alignments of the different parts. The efficiency of this technique is demonstrated on three samples, an intermetallic sample with deformation misalignments due to a high electron dose typical to spectroscopic electron tomography, a porous silicon sample with an extremely thin end particularly sensitive to electron beam and another porous silicon sample that was drifting during image acquisitions. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Formation of Dawn-Dusk Asymmetry in Earth's Magnetotail Thin Current Sheet: A Three-Dimensional Particle-In-Cell Simulation

NASA Astrophysics Data System (ADS)

Lu, San; Pritchett, P. L.; Angelopoulos, V.; Artemyev, A. V.

2018-04-01

Using a three-dimensional particle-in-cell simulation, we investigate the formation of dawn-dusk asymmetry in Earth's magnetotail. The magnetotail current sheet is compressed by an external driving electric field down to a thickness on the order of ion kinetic scales. In the resultant thin current sheet (TCS) where the magnetic field line curvature radius is much smaller than ion gyroradius, a significant portion of the ions becomes unmagnetized and decoupled from the magnetized electrons, giving rise to a Hall electric field Ez and an additional cross-tail current jy caused by the unmagnetized ions being unable to comove with the electrons in the Hall electric field. The Hall electric field transports via E × B drift magnetic flux and magnetized plasma dawnward, causing a reduction of the current sheet thickness and the normal magnetic field Bz on the duskside. This leads to an even stronger Hall effect (stronger jy and Ez) in the duskside TCS. Thus, due to the internal kinetic effects in the TCS, namely, the Hall effect and the associated dawnward E × B drift, the magnetotail dawn-dusk asymmetry forms in a short time without any global, long-term effects. The duskside preference of reconnection and associated dynamic phenomena (such as substorm onsets, dipolarizing flux bundles, fast flows, energetic particle injections, and flux ropes), which has been pervasively observed by spacecraft in the past 20 years, can thus be explained as a consequence of this TCS asymmetry.

Robust video transmission with distributed source coded auxiliary channel.

PubMed

Wang, Jiajun; Majumdar, Abhik; Ramchandran, Kannan

2009-12-01

We propose a novel solution to the problem of robust, low-latency video transmission over lossy channels. Predictive video codecs, such as MPEG and H.26x, are very susceptible to prediction mismatch between encoder and decoder or "drift" when there are packet losses. These mismatches lead to a significant degradation in the decoded quality. To address this problem, we propose an auxiliary codec system that sends additional information alongside an MPEG or H.26x compressed video stream to correct for errors in decoded frames and mitigate drift. The proposed system is based on the principles of distributed source coding and uses the (possibly erroneous) MPEG/H.26x decoder reconstruction as side information at the auxiliary decoder. The distributed source coding framework depends upon knowing the statistical dependency (or correlation) between the source and the side information. We propose a recursive algorithm to analytically track the correlation between the original source frame and the erroneous MPEG/H.26x decoded frame. Finally, we propose a rate-distortion optimization scheme to allocate the rate used by the auxiliary encoder among the encoding blocks within a video frame. We implement the proposed system and present extensive simulation results that demonstrate significant gains in performance both visually and objectively (on the order of 2 dB in PSNR over forward error correction based solutions and 1.5 dB in PSNR over intrarefresh based solutions for typical scenarios) under tight latency constraints.

3D Late Gadolinium Enhancement in a Single Prolonged Breath-hold using Supplemental Oxygenation and Hyperventilation

PubMed Central

Roujol, Sébastien; Basha, Tamer A.; Akçakaya, Mehmet; Foppa, Murilo; Chan, Raymond H.; Kissinger, Kraig V.; Goddu, Beth; Berg, Sophie; Manning, Warren J.; Nezafat, Reza

2013-01-01

Purpose: To evaluate the feasibility of 3D single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Methods: Breath-hold metrics (breath-hold duration, diaphragmatic/LV position drift, and maximum variation of RR interval) without and with supplemental oxygen and hyperventilation were assessed in healthy adult subjects using a real time single shot acquisition. Ten healthy subjects and 13 patients then underwent assessment of the proposed 3D breath-hold LGE acquisition (FOV=320×320×100 mm3, resolution=1.6×1.6×5.0 mm3, acceleration rate of 4) and a free breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semi-quantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Results: Supplemental oxygenation and hyperventilation increased the breath-hold duration (35±11 s to 58±21 s, p<0.0125) without significant impact on diaphragmatic/LV position drift or maximum variation of RR interval (both p>0.01). LGE images were of similar quality when compared to free breathing acquisitions but with reduced total scan time (85±22 s to 35±6 s, p<0.001). Conclusions: Supplemental oxygenation and hyperventilation allow for prolonged breath-holding and enable single breath-hold 3D accelerated LGE with similar image quality as free breathing with NAV. PMID:24186772

Vector quantizer based on brightness maps for image compression with the polynomial transform

NASA Astrophysics Data System (ADS)

Escalante-Ramirez, Boris; Moreno-Gutierrez, Mauricio; Silvan-Cardenas, Jose L.

2002-11-01

We present a vector quantization scheme acting on brightness fields based on distance/distortion criteria correspondent with psycho-visual aspects. These criteria quantify sensorial distortion between vectors that represent either portions of a digital image or alternatively, coefficients of a transform-based coding system. In the latter case, we use an image representation model, namely the Hermite transform, that is based on some of the main perceptual characteristics of the human vision system (HVS) and in their response to light stimulus. Energy coding in the brightness domain, determination of local structure, code-book training and local orientation analysis are all obtained by means of the Hermite transform. This paper, for thematic reasons, is divided in four sections. The first one will shortly highlight the importance of having newer and better compression algorithms. This section will also serve to explain briefly the most relevant characteristics of the HVS, advantages and disadvantages related with the behavior of our vision in front of ocular stimulus. The second section shall go through a quick review of vector quantization techniques, focusing their performance on image treatment, as a preview for the image vector quantizer compressor actually constructed in section 5. Third chapter was chosen to concentrate the most important data gathered on brightness models. The building of this so-called brightness maps (quantification of the human perception on the visible objects reflectance), in a bi-dimensional model, will be addressed here. The Hermite transform, a special case of polynomial transforms, and its usefulness, will be treated, in an applicable discrete form, in the fourth chapter. As we have learned from previous works 1, Hermite transform has showed to be a useful and practical solution to efficiently code the energy within an image block, deciding which kind of quantization is to be used upon them (whether scalar or vector). It will also be a unique tool to structurally classify the image block within a given lattice. This particular operation intends to be one of the main contributions of this work. The fifth section will fuse the proposals derived from the study of the three main topics- addressed in the last sections- in order to propose an image compression model that takes advantage of vector quantizers inside the brightness transformed domain to determine the most important structures, finding the energy distribution inside the Hermite domain. Sixth and last section will show some results obtained while testing the coding-decoding model. The guidelines to evaluate the image compressing performance were the compression ratio, SNR and psycho-visual quality. Some conclusions derived from the research and possible unexplored paths will be shown on this section as well.

Fluid outlet at the bottom of an in situ oil shale retort

DOEpatents

Hutchins, Ned M.

1984-01-01

Formation is excavated from within the boundaries of a retort site in formation containing oil shale for forming at least one retort level void extending horizontally across the retort site, leaving at least one remaining zone of unfragmented formation within the retort site. A production level drift is excavated below the retort level void, leaving a lower zone of unfragmented formation between the retort level void and the production level drift. A plurality of raises are formed between the production level drift and the retort level void for providing product withdrawal passages distributed generally uniformly across the horizontal cross section of the retort level void. The product withdrawal passages are backfilled with a permeable mass of particles. Explosive placed within the remaining zone of unfragmented formation above the retort level void is detonated for explosively expanding formation within the retort site toward at least the retort level void for forming a fragmented permeable mass of formation particles containing oil shale within the boundaries of the retort site. During retorting operations products of retorting are conducted from the fragmented mass in the retort through the product withdrawal passages to the production level void. The products are withdrawn from the production level void.

77 FR 50500 - California State Nonroad Engine Pollution Control Standards; California Nonroad Compression...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-21

... EPA that it has adopted additional amendments to its emission standards for fleets that operate... standards and accompanying enforcement procedures must be consistent with section 209(a), section 209(e)(1... standards and enforcement procedures must be consistent with section 209(e)(1), which identifies the...

29 CFR 1926.803 - Compressed air.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (3) In the event an employee is absent from work for 10 days, or is absent due to sickness or injury... subpart. (2) In the event it is necessary for an employee to be in compressed air more than once in a 24... in the event of an emergency, as provided in paragraph (g)(1)(viii) of this section. (iv) A manual...

Test Methods for Composites: A Status Report. Volume 2. Compression Test Methods

DTIC Science & Technology

1993-06-01

glass and Kevlar fibers in a phenolic matrix) were relatively thick (24 plies), and more importantly, failed at very low compressive strength levels...ICH LAMINATE SPECIMEN TEST METHOD ........................................ 29 2.4 RECOMMENDATIONS...Thickness in the Middle of the Gage Section, for Four Laminate Thicknesses [711 ................... 143 52. Axial Stress Distributions in an AS4/3502 Carbon

Method for obtaining large levitation pressure in superconducting magnetic bearings

DOEpatents

Hull, John R.

1997-01-01

A method and apparatus for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap.

Method for obtaining large levitation pressure in superconducting magnetic bearings

DOEpatents

Hull, John R.

1996-01-01

A method and apparatus for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap.

49 CFR 178.337 - Specification MC 331; cargo tank motor vehicle primarily for transportation of compressed gases...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Specification MC 331; cargo tank motor vehicle primarily for transportation of compressed gases as defined in subpart G of part 173 of this subchapter. 178.337 Section 178.337 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...

49 CFR 178.337 - Specification MC 331; cargo tank motor vehicle primarily for transportation of compressed gases...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Specification MC 331; cargo tank motor vehicle primarily for transportation of compressed gases as defined in subpart G of part 173 of this subchapter. 178.337 Section 178.337 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY...

Hydrodynamically Lubricated Rotary Shaft Having Twist Resistant Geometry

DOEpatents

Dietle, Lannie; Gobeli, Jeffrey D.

1993-07-27

A hydrodynamically lubricated squeeze packing type rotary shaft with a cross-sectional geometry suitable for pressurized lubricant retention is provided which, in the preferred embodiment, incorporates a protuberant static sealing interface that, compared to prior art, dramatically improves the exclusionary action of the dynamic sealing interface in low pressure and unpressurized applications by achieving symmetrical deformation of the seal at the static and dynamic sealing interfaces. In abrasive environments, the improved exclusionary action results in a dramatic reduction of seal and shaft wear, compared to prior art, and provides a significant increase in seal life. The invention also increases seal life by making higher levels of initial compression possible, compared to prior art, without compromising hydrodynamic lubrication; this added compression makes the seal more tolerant of compression set, abrasive wear, mechanical misalignment, dynamic runout, and manufacturing tolerances, and also makes hydrodynamic seals with smaller cross-sections more practical. In alternate embodiments, the benefits enumerated above are achieved by cooperative configurations of the seal and the gland which achieve symmetrical deformation of the seal at the static and dynamic sealing interfaces. The seal may also be configured such that predetermined radial compression deforms it to a desired operative configuration, even through symmetrical deformation is lacking.

Electrodes for solid state gas sensor

DOEpatents

Mukundan, Rangachary [Santa Fe, NM; Brosha, Eric L [Los Alamos, NM; Garzon, Fernando [Santa Fe, NM

2007-05-08

A mixed potential electrochemical sensor for the detection of gases has a ceria-based electrolyte with a surface for exposing to the gases to be detected, and with a reference wire electrode and a sensing wire electrode extending through the surface and fixed within the electrolyte as the electrolyte is compressed and sintered. The electrochemical sensor is formed by placing a wire reference electrode and a wire sensing electrode in a die, where each electrode has a first compressed planar section and a second section depending from the first section with the second section of each electrode extending axially within the die. The die is filled with an oxide-electrolyte powder and the powder is pressed within the die with the wire electrodes. The wire-electrodes and the pressed oxide-electrolyte powder are sintered to form a ceramic electrolyte base with a reference wire electrode and a sensing wire electrode depending therefrom.

Electrodes for solid state gas sensor

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

Mukundan, Rangachary; Brosha, Eric L; Garzon, Fernando

2007-05-08

A mixed potential electrochemical sensor for the detection of gases has a ceria-based electrolyte with a surface for exposing to the gases to be detected, and with a reference wire electrode and a sensing wire electrode extending through the surface and fixed within the electrolyte as the electrolyte is compressed and sintered. The electrochemical sensor is formed by placing a wire reference electrode and a wire sensing electrode in a die, where each electrode has a first compressed planar section and a second section depending from the first section with the second section of each electrode extending axially within themore » die. The die is filled with an oxide-electrolyte powder and the powder is pressed within the die with the wire electrodes. The wire-electrodes and the pressed oxide-electrolyte powder are sintered to form a ceramic electrolyte base with a reference wire electrode and a sensing wire electrode depending therefrom.« less

Electrodes for solid state gas sensor

DOEpatents

Mukundan, Rangachary; Brosha, Eric L.; Garzon, Fernando

2003-08-12

A mixed potential electrochemical sensor for the detection of gases has a ceria-based electrolyte with a surface for exposing to the gases to be detected, and with a reference wire electrode and a sensing wire electrode extending through the surface and fixed within the electrolyte as the electrolyte is compressed and sintered. The electrochemical sensor is formed by placing a wire reference electrode and a wire sensing electrode in a die, where each electrode has a first compressed planar section and a second section depending from the first section with the second section of each electrode extending axially within the die. The die is filled with an oxide-electrolyte powder and the powder is pressed within the die with the wire electrodes. The wire-electrodes and the pressed oxide-electrolyte powder are sintered to form a ceramic electrolyte base with a reference wire electrode and a sensing wire electrode depending therefrom.

Behavioral and catastrophic drift of invertebrates in two streams in northeastern Wyoming

USGS Publications Warehouse

Wangsness, David J.; Peterson, David A.

1980-01-01

Invertebrate drift samples were collected in August 1977 from two streams in the Powder River structural basin in northeastern Wyoming. The streams are Clear Creek, a mountain stream, and the Little Powder River, a plains stream. Two major patterns of drift were recognized. Clear Creek was sampled during a period of normal seasonal conditions. High drift rates occurred during the night indicating a behavioral drift pattern that is related to the benthic invertebrate density and carrying capacity of the stream substrates. The mayfly genes Baetis, a common drift organism, dominated the peak periods of drift in Clear Creek. The Little Powder River has a high discharge during the study period. Midge larvae of the families Chironomidae and Ceratopogonidae, ususally not common in drift, dominated the drift community. The dominance of midge larvae, the presence of several other organisms not common in drift, and the high discharge during the study period caused a catastrophic drift pattern. (USGS)

The strength of compressed structures with CFRP materials reinforcement when exceeding the cross-section size

NASA Astrophysics Data System (ADS)

Polskoy, Petr; Mailyan, Dmitry; Georgiev, Sergey; Muradyan, Viktor

2018-03-01

The increase of high-rise construction volume or «High-Rise Construction» requires the use of high-strength concrete and that leads to the reduction in section size of structures and to the decrease in material consumption. First of all, it refers to the compressed elements for which, when the transverse dimensions are reduced, their flexibility and deformation increase but the load bearing capacity decreases. Growth in construction also leads to the increase of repair and restoration works or to the strengthening of structures. The most effective method of their strengthening in buildings of «High-Rise Construction» is the use of composite materials which reduces the weight of reinforcement elements and labour costs on execution of works. In this article the results of experimental research on strength and deformation of short compressed reinforced concrete structures, reinforced with external carbon fiber reinforcement, are presented. Their flexibility is λh=10, and the cross-section dimensions ratio b/h is 2, that is 1,5 times more, than recommended by standards in Russia. The following research was being done for three kinds of strained and deformed conditions with different variants of composite reinforcement. The results of the experiment proved the real efficiency of composite reinforcement of the compressed elements with sides ratio equal to 2, increasing the bearing capacity of pillars till 1,5 times. These results can be used for designing the buildings of different number of storeys.

Sampling of Stochastic Input Parameters for Rockfall Calculations and for Structural Response Calculations Under Vibratory Ground Motion

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

M. Gross

2004-09-01

The purpose of this scientific analysis is to define the sampled values of stochastic (random) input parameters for (1) rockfall calculations in the lithophysal and nonlithophysal zones under vibratory ground motions, and (2) structural response calculations for the drip shield and waste package under vibratory ground motions. This analysis supplies: (1) Sampled values of ground motion time history and synthetic fracture pattern for analysis of rockfall in emplacement drifts in nonlithophysal rock (Section 6.3 of ''Drift Degradation Analysis'', BSC 2004 [DIRS 166107]); (2) Sampled values of ground motion time history and rock mechanical properties category for analysis of rockfall inmore » emplacement drifts in lithophysal rock (Section 6.4 of ''Drift Degradation Analysis'', BSC 2004 [DIRS 166107]); (3) Sampled values of ground motion time history and metal to metal and metal to rock friction coefficient for analysis of waste package and drip shield damage to vibratory motion in ''Structural Calculations of Waste Package Exposed to Vibratory Ground Motion'' (BSC 2004 [DIRS 167083]) and in ''Structural Calculations of Drip Shield Exposed to Vibratory Ground Motion'' (BSC 2003 [DIRS 163425]). The sampled values are indices representing the number of ground motion time histories, number of fracture patterns and rock mass properties categories. These indices are translated into actual values within the respective analysis and model reports or calculations. This report identifies the uncertain parameters and documents the sampled values for these parameters. The sampled values are determined by GoldSim V6.04.007 [DIRS 151202] calculations using appropriate distribution types and parameter ranges. No software development or model development was required for these calculations. The calculation of the sampled values allows parameter uncertainty to be incorporated into the rockfall and structural response calculations that support development of the seismic scenario for the Total System Performance Assessment for the License Application (TSPA-LA). The results from this scientific analysis also address project requirements related to parameter uncertainty, as specified in the acceptance criteria in ''Yucca Mountain Review Plan, Final Report'' (NRC 2003 [DIRS 163274]). This document was prepared under the direction of ''Technical Work Plan for: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 170528]) which directed the work identified in work package ARTM05. This document was prepared under procedure AP-SIII.9Q, ''Scientific Analyses''. There are no specific known limitations to this analysis.« less

Seasonal Variation, Export Dynamics and Consumption of Freshwater Invertebrates in an Estuarine Environment

NASA Astrophysics Data System (ADS)

Williams, D. D.; Williams, N. E.

1998-03-01

In the Aber Estuary, North Wales, significant numbers of freshwater benthic invertebrates occurred in the tidal freshwater area. Distinct seasonal patterns were observed in their longitudinal zonation which appeared to be unrelated to variations in tidal inundation. The December extension downstream of freshwater taxa is hypothesized to be in response to decreasing water temperatures. In April, larvae/nymphs of the Trichoptera (caddisflies), Ephemeroptera (mayflies) and Plecoptera (stoneflies) ranged as far as a site inundated by 80·9% of all high tides, and larval Elmidae and Chironomidae (midges) occurred at the most marine site (inundated twice daily by all high tides). In July, with the exception of the Chironomidae, the range of most aquatic insects had contracted to the upper estuary. Although, in general, densities of aquatic insects decreased towards the lower estuary, significant densities persisted there. For example, maxima of 3514 chironomid larvae and 48 caddisfly larvae m -2were recorded at the 80·9% inundation site. An estimated 31×10 6freshwater invertebrates (weighing 62·6 kg), per annum, passed from fresh water into salt water across any given transect along the estuary. In comparison, the annual influx of invertebrates carried upstream by incoming tides was estimated to be 1·9×10 6(6·2%; weighing 2·5 kg). Predominant in the downstream drift were the larvae/nymphs and/or pupae of chironomids, mayflies, stoneflies and caddisflies. The ' reverse ' drift comprised mainly copepods, ostracods, amphipods and oligochaetes. Mites and the brackishwater amphipod Gammarus zaddachicommonly moved in both directions. Highest drift densities occurred in July, whereas the lowest densities occurred in late autumn and winter. Multiple regression analysis showed no relationship between total drift or ' reverse ' drift densities and any of the measured environmental variables. Many of the freshwater invertebrates appeared not to die upon passing into tidal sections but resumed a benthic existence by virtue of varying degrees of salt tolerance. Of the three fish species common in the estuary, eel, common goby and flounder, the last two preyed measurably on freshwater taxa. Whereas gobies tended to be opportunistic feeders, depending on the section of estuary that they occupied, flounder were more restricted to the upper estuary where they fed selectively on chironomid larvae. On the latter diet, between March and September, the mean wet weight of flounders increased by more than 100 times (from 5 to 540 mg). Gobies were more numerous in the estuary from September to February, and although they ate insects their primary prey was G. zaddachi.

Gas turbine cooling system

DOEpatents

Bancalari, Eduardo E.

2001-01-01

A gas turbine engine (10) having a closed-loop cooling circuit (39) for transferring heat from the hot turbine section (16) to the compressed air (24) produced by the compressor section (12). The closed-loop cooling system (39) includes a heat exchanger (40) disposed in the flow path of the compressed air (24) between the outlet of the compressor section (12) and the inlet of the combustor (14). A cooling fluid (50) may be driven by a pump (52) located outside of the engine casing (53) or a pump (54) mounted on the rotor shaft (17). The cooling circuit (39) may include an orifice (60) for causing the cooling fluid (50) to change from a liquid state to a gaseous state, thereby increasing the heat transfer capacity of the cooling circuit (39).

Structural efficiency studies of corrugated compression panels with curved caps and beaded webs

NASA Technical Reports Server (NTRS)

Davis, R. C.; Mills, C. T.; Prabhakaran, R.; Jackson, L. R.

1984-01-01

Curved cross-sectional elements are employed in structural concepts for minimum-mass compression panels. Corrugated panel concepts with curved caps and beaded webs are optimized by using a nonlinear mathematical programming procedure and a rigorous buckling analysis. These panel geometries are shown to have superior structural efficiencies compared with known concepts published in the literature. Fabrication of these efficient corrugation concepts became possible by advances made in the art of superplastically forming of metals. Results of the mass optimization studies of the concepts are presented as structural efficiency charts for axial compression.

Spiral biasing adaptor for use in Si drift detectors and Si drift detector arrays

DOEpatents

Li, Zheng; Chen, Wei

2016-07-05

A drift detector array, preferably a silicon drift detector (SDD) array, that uses a low current biasing adaptor is disclosed. The biasing adaptor is customizable for any desired geometry of the drift detector single cell with minimum drift time of carriers. The biasing adaptor has spiral shaped ion-implants that generate the desired voltage profile. The biasing adaptor can be processed on the same wafer as the drift detector array and only one biasing adaptor chip/side is needed for one drift detector array to generate the voltage profiles on the front side and back side of the detector array.

On the Nocturnal Downward and Westward Equatorial Ionospheric Plasma Drifts During the 17 March 2015 Geomagnetic Storm

NASA Astrophysics Data System (ADS)

Bagiya, Mala S.; Vichare, Geeta; Sinha, A. K.; Sripathi, S.

2018-02-01

During quiet period, the nocturnal equatorial ionospheric plasma drifts eastward in the zonal direction and downward in the vertical direction. This quiet time drift pattern could be understood through dynamo processes in the nighttime equatorial ionosphere. The present case study reports the nocturnal simultaneous occurrence of the vertically downward and zonally westward plasma drifts over the Indian latitudes during the geomagnetic storm of 17 March 2015. After 17:00 UT ( 22:10 local time), the vertical plasma drift became downward and coincided with the westward zonal drift, a rarely observed feature of low latitude plasma drifts. The vertical drift turned upward after 18:00 UT, while the zonal drift became eastward. We mainly emphasize here the distinct bipolar type variations of vertical and zonal plasma drifts observed around 18:00 UT. We explain the vertical plasma drift in terms of the competing effects between the storm time prompt penetration and disturbance dynamo electric fields. Whereas, the westward drift is attributed to the storm time local electrodynamical changes mainly through the disturbance dynamo field in addition to the vertical Pedersen current arising from the spatial (longitudinal) gradient of the field aligned Pedersen conductivity.

Scalable Graphene-Based Membranes for Ionic Sieving with Ultrahigh Charge Selectivity.

PubMed

Hong, Seunghyun; Constans, Charlotte; Surmani Martins, Marcos Vinicius; Seow, Yong Chin; Guevara Carrió, Juan Alfredo; Garaj, Slaven

2017-02-08

Nanostructured graphene-oxide (GO) laminate membranes, exhibiting ultrahigh water flux, are excellent candidates for next generation nanofiltration and desalination membranes, provided the ionic rejection could be further increased without compromising the water flux. Using microscopic drift-diffusion experiments, we demonstrated the ultrahigh charge selectivity for GO membranes, with more than order of magnitude difference in the permeabilities of cationic and anionic species of equivalent hydration radii. Measuring diffusion of a wide range of ions of different size and charge, we were able to clearly disentangle different physical mechanisms contributing to the ionic sieving in GO membranes: electrostatic repulsion between ions and charged chemical groups; and the compression of the ionic hydration shell within the membrane's nanochannels, following the activated behavior. The charge-selectivity allows us to rationally design membranes with increased ionic rejection and opens up the field of ion exchange and electrodialysis to the GO membranes.

System and Method for Monitoring Distributed Asset Data

NASA Technical Reports Server (NTRS)

Gorinevsky, Dimitry (Inventor)

2015-01-01

A computer-based monitoring system and monitoring method implemented in computer software for detecting, estimating, and reporting the condition states, their changes, and anomalies for many assets. The assets are of same type, are operated over a period of time, and outfitted with data collection systems. The proposed monitoring method accounts for variability of working conditions for each asset by using regression model that characterizes asset performance. The assets are of the same type but not identical. The proposed monitoring method accounts for asset-to-asset variability; it also accounts for drifts and trends in the asset condition and data. The proposed monitoring system can perform distributed processing of massive amounts of historical data without discarding any useful information where moving all the asset data into one central computing system might be infeasible. The overall processing is includes distributed preprocessing data records from each asset to produce compressed data.

22. Power plant engine pipingcompressed air piping diagram and sections, ...

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

22. Power plant engine piping-compressed air piping diagram and sections, sheet 81 of 130 - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

[Radiation Tolerant Electronics

NASA Technical Reports Server (NTRS)

1996-01-01

Research work in the providing radiation tolerant electronics to NASA and the commercial sector is reported herein. There are four major sections to this report: (1) Special purpose VLSI technology section discusses the status of the VLSI projects as well as the new background technologies that have been developed; (2) Lossless data compression results provide the background and direction of new data compression pursued under this grant; (3) Commercial technology transfer presents an itemization of the commercial technology transfer; and (4) Delivery of VLSI to the Government is a solution and progress report that shows how the Government and Government contractors are gaining access to the technology that has been developed by the MRC.

Opposite Latitudinal Dependence of the Premidnight and Postmidnight Oscillations in the Electron Density of Midlatitude F Layer

NASA Astrophysics Data System (ADS)

Chen, Gang; Wang, Jin; Zhang, Shaodong; Deng, Zhongxin; Zhong, Dingkun; Wu, Chen; Jin, Han; Li, Yaxian

2018-01-01

The dense observation points of the oblique-incidence ionosonde network in North China make it possible to discover the ionospheric regional variations with relatively high spatial resolution. The ionosonde network and the Beijing digisonde are used to investigate the ionospheric nighttime oscillations in January and February 2011. The electron density enhancements occurring before and after midnight present the obvious opposite latitudinal dependence in the time-latitude maps, which are composed by the differential critical frequency of F2 layer. The premidnight enhancements (PRMEs) appeared earlier in the north and then moved to south. The postmidnight enhancements (POMEs) did the opposite. The data analysis shows that the PRME was a part of the large-scale traveling ionospheric disturbance (LSTID), which may be produced by gravity waves. The southward propagation of the LSTIDs is considered to form the positive latitudinal dependence of the wave peaks and troughs. The postmidnight F layer oscillation was composed by a single enhancement and a single decline following it. The westward electric field-induced E × B drift, which pushed the F layer to lower altitudes with higher recombination loss, was most likely to compress the plasma and produce the POMEs. Along with the continuously dropping of the layer, the recombination loss exceeded the density increase due to the compression effect and then the electron density decline appeared.

Initial dislocation structure and dynamic dislocation multiplication in Mo single crystals

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

Hsiung, L M; Lassila, D H

Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied in order to investigate dislocation multiplication mechanisms in the early stages of plastic deformation. The initial dislocation density is in a range of 10{sup 6} {approx} 10{sup 7} cm{sup -2}, and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 10{sup 8} {approx} 10{sup 9} cm{sup -2}, and the average jog height is also found to increase after compressing for a total strain ofmore » 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. Both the jog height and length of link segment (between jogs) can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This dynamic dislocation multiplication source is subsequently verified by direct simulations of dislocation dynamics under stress to be crucial in the early stages of plastic deformation in Mo single crystals.« less

Front End and HFOFO Snake for a Muon Facility

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

Neuffer, D.; Alexahin, Y.

2015-09-01

A neutrino factory or muon collider requires the capture and cooling of a large number of muons. Scenarios for capture, bunching, phase-energy rotation and initial cooling of μ’s produced from a proton source target have been developed, for neutrino factory and muon collider scenarios. They require a drift section from the target, a bunching section and amore » $$\\phi-\\delta E$$ rotation section leading into the cooling channel. The currently preferred cooling channel design is an “HFOFO Snake” configuration that cools both $$\\mu^+$$ and $$\\mu^-$$ transversely and longitudinally. The status of the design is presented and variations are discussed.« less

The relation between invertebrate drift and two primary controls, discharge and benthic densities, in a large regulated river

USGS Publications Warehouse

Kennedy, Theodore A.; Yackulic, Charles B.; Cross, Wyatt F.; Grams, Paul E.; Yard, Michael D.; Copp, Adam J.

2014-01-01

1. Invertebrate drift is a fundamental process in streams and rivers. Studies from laboratory experiments and small streams have identified numerous extrinsic (e.g. discharge, light intensity, water quality) and intrinsic factors (invertebrate life stage, benthic density, behaviour) that govern invertebrate drift concentrations (# m−3), but the factors that govern invertebrate drift in larger rivers remain poorly understood. For example, while large increases or decreases in discharge can lead to large increases in invertebrate drift, the role of smaller, incremental changes in discharge is poorly described. In addition, while we might expect invertebrate drift concentrations to be proportional to benthic densities (# m−2), the benthic–drift relation has not been rigorously evaluated. 2. Here, we develop a framework for modelling invertebrate drift that is derived from sediment transport studies. We use this framework to guide the analysis of high-resolution data sets of benthic density and drift concentration for four important invertebrate taxa from the Colorado River downstream of Glen Canyon Dam (mean daily discharge 325 m3 s−1) that were collected over 18 months and include multiple observations within days. Ramping of regulated flows on this river segment provides an experimental treatment that is repeated daily and allowed us to describe the functional relations between invertebrate drift and two primary controls, discharge and benthic densities. 3. Twofold daily variation in discharge resulted in a >10-fold increase in drift concentrations of benthic invertebrates associated with pools and detritus (i.e. Gammarus lacustris and Potamopyrgus antipodarum). In contrast, drift concentrations of sessile blackfly larvae (Simuliium arcticum), which are associated with high-velocity cobble microhabitats, decreased by over 80% as discharge doubled. Drift concentrations of Chironomidae increased proportional to discharge. 4. Drift of all four taxa was positively related to benthic density. Drift concentrations of Gammarus, Potamopyrgus and Chironomidae were proportional to benthic density. Drift concentrations of Simulium were positively related to benthic density, but the benthic–drift relation was less than proportional (i.e. a doubling of benthic density only led to a 40% increase in drift concentrations). 5. Our study demonstrates that invertebrate drift concentrations in the Colorado River are jointly controlled by discharge and benthic densities, but these controls operate at different timescales. Twofold daily variation in discharge associated with hydropeaking was the primary control on within-day variation in invertebrate drift concentrations. In contrast, benthic density, which varied 10- to 1000-fold among sampling dates, depending on the taxa, was the primary control on invertebrate drift concentrations over longer timescales (weeks to months).

Effect of natural windbreaks on drift reduction in orchard spraying.

PubMed

Wenneker, M; Heijne, B; van de Zande, J C

2005-01-01

In the Netherlands windbreaks are commonly grown to protect orchards against wind damage and to improve micro-climate. Natural windbreaks of broad-leaved trees can also reduce the risk of surface water contamination caused by spray drift during orchard spraying. Spray drift from pesticide applications is a major concern in the Netherlands, especially drift into water courses. So far, several drift reducing measures have been accepted by water quality control organisations and the Board for the Authorization of Pesticides (CTB), e.g. presence of a windbreak (i.e. 70% drift reduction at early season and 90% drift reduction at full leaf, respectively before and after first of May). From the experiments it was concluded that the risk of drift contamination is high during the early developmental stages of the growing season. The 70% drift reduction at early season as determined in previous experiments, appears to be valid only for windbreaks with a certain degree of developed leaves. At full leaf stage 80-90% drift reduction by the windbreak was measured. The use of evergreen windbreaks or wind-break species that develop in early season can reduce the risk of drift contamination considerably. Also, the combination of drift reducing methods, such as one-sided spraying of the last tree row and a windbreak is an effective method to reduce spray drift in the Netherlands in early season.

Method for obtaining large levitation pressure in superconducting magnetic bearings

DOEpatents

Hull, J.R.

1997-08-05

A method and apparatus are disclosed for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap. 4 figs.

Method for obtaining large levitation pressure in superconducting magnetic bearings

DOEpatents

Hull, J.R.

1996-10-08

A method and apparatus are disclosed for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap. 4 figs.

49 CFR 173.304b - Additional requirements for shipment of liquefied compressed gases in UN pressure receptacles.

Code of Federal Regulations, 2010 CFR

2010-10-01

... determined as follows: (1) For high pressure liquefied gases, in no case may the filling ratio of the settled... than the vapor pressure of the liquid at 65 °C. (3) For high pressure liquefied gases or gas mixtures... compressed gases in UN pressure receptacles. 173.304b Section 173.304b Transportation Other Regulations...

Characteristics of the equatorial plasma drifts as obtained by using Canadian Doppler ionosonde over southern tip of India

NASA Astrophysics Data System (ADS)

Sripathi, S.; Singh, Ram; Banola, S.; Sreekumar, Sreeba; Emperumal, K.; Selvaraj, C.

2016-08-01

We present here characteristics of the Doppler drift measurements over Tirunelveli (8.73°N, 77.70°E; dip 0.5°N), an equatorial site over Southern India using Doppler interferometry technique of Canadian ionosonde. Three-dimensional bulk motions of the scatterers as reflected from the ionosphere are derived by using Doppler interferometry technique at selected frequencies using spaced receivers arranged in magnetic E-W and N-S directions. After having compared with Lowell's digisonde drifts at Trivandrum, we studied the temporal and seasonal variabilities of quiet time drifts for the year 2012. The observations showed higher vertical drifts during post sunset in the equinox followed by winter and summer seasons. The comparison of Doppler vertical drifts with the drifts obtained from (a) virtual height and (b) Fejer drift model suggests that Doppler vertical drifts are relatively higher as compared to the drifts obtained from model and virtual height methods. Further, it is seen that vertical drifts exhibited equinoctial asymmetry in prereversal enhancement quite similar to such asymmetry observed in the spread F in the ionograms and GPS L band scintillations. The zonal drifts, on the other hand, showed westward during daytime with mean drifts of ~150-200 m/s and correlated well with equatorial electrojet strength indicating the role of E region dynamo during daytime, while they are eastward during nighttime with mean drifts of ~100 m/s resembling F region dynamo process. Also, zonal drifts showed large westward prior to the spread F onset during autumn equinox than vernal equinox, suggesting strong zonal shears which might cause equinoctial asymmetry in spread F.

Compressible Flow Toolbox

NASA Technical Reports Server (NTRS)

Melcher, Kevin J.

2006-01-01

The Compressible Flow Toolbox is primarily a MATLAB-language implementation of a set of algorithms that solve approximately 280 linear and nonlinear classical equations for compressible flow. The toolbox is useful for analysis of one-dimensional steady flow with either constant entropy, friction, heat transfer, or Mach number greater than 1. The toolbox also contains algorithms for comparing and validating the equation-solving algorithms against solutions previously published in open literature. The classical equations solved by the Compressible Flow Toolbox are as follows: The isentropic-flow equations, The Fanno flow equations (pertaining to flow of an ideal gas in a pipe with friction), The Rayleigh flow equations (pertaining to frictionless flow of an ideal gas, with heat transfer, in a pipe of constant cross section), The normal-shock equations, The oblique-shock equations, and The expansion equations.

Self-shielding flex-circuit drift tube, drift tube assembly and method of making

DOEpatents

Jones, David Alexander

2016-04-26

The present disclosure is directed to an ion mobility drift tube fabricated using flex-circuit technology in which every other drift electrode is on a different layer of the flex-circuit and each drift electrode partially overlaps the adjacent electrodes on the other layer. This results in a self-shielding effect where the drift electrodes themselves shield the interior of the drift tube from unwanted electro-magnetic noise. In addition, this drift tube can be manufactured with an integral flex-heater for temperature control. This design will significantly improve the noise immunity, size, weight, and power requirements of hand-held ion mobility systems such as those used for explosive detection.

Quantification of Stokes Drift as a Mechanism for Surface Oil Advection in the DWH Oil Spill

NASA Astrophysics Data System (ADS)

Clark, M.

2013-12-01

Stokes drift has previously been qualitatively shown to be a factor in ocean surface particle transport, but has never been comprehensively quantified. In addition, most operational ocean particle advection models used during the Deepwater Horizon oil spill do not explicitly account for Stokes drift, instead using a simple parameterization based on wind drift (or ignoring it completely). This research works to quantify Stokes drift via direct calculation, with a focus on shallow water, where Stokes drift is more likely to have a relatively large impact compared to other transport processes such as ocean currents. For this study, WaveWatch III modeled waves in the Gulf of Mexico are used, from which Stokes drift is calculated using the peak wave period and significant wave height outputs. Trajectories are also calculated to examine the role Stokes drift plays in bringing surface particles (and specifically surface oil slicks) onshore. The impact of Stokes drift is compared to transport by currents and traditional estimates of wind drift.

Geologic, geophysical, and in situ stress investigations in the vicinity of the Dining Car Chimney, Dining Car/Hybla gold tunnels, Nevada Test Site, with sections on geologica investigations, geophysical investigations, and in situ stress investigations

USGS Publications Warehouse

Townsend, D.R.; Baldwin, M.J.; Carroll, R.D.; Ellis, W.L.; Magner, J.E.

1982-01-01

The Hybla Gold experiment was conducted in the U12e.20 drifts of the E-tunnel complex beneath the surface of Rainier Mesa at the Nevada Test Site. Though the proximity of the Hybla Gold working point to the chimney of the Dining Car event was important to the experiment, the observable geologic effects from Dining Car on the Hybla Gold site were minor. Overburden above the working point is approximately 385 m (1,263 ft). The pre-Tertiary surface, probably quartzite, lies approximately 254 m (833 ft) below the working point. The drifts are mined in zeolitized ash-fall tuffs of tunnel bed 4, subunits K and J, all of Miocene age. The working point is in subunit 4J. Geologic structure in the region around the working point is not complex. The U12e.20 main drift follows the axis of a shallow depositional syncline. A northeast-dipping fault with displacement of approximately 3 m (10 ft) passes within 15.2 m (50 ft) of the Hybla Gold working point. Three faults of smaller displacement pass within 183-290 m (600-950 ft) of the working point, and are antithetic to the 3-m (10-ft) fault. Three exploratory holes were drilled to investigate the chimney of the nearby Dining Car event. Four horizontal holes were drilled during the construction of the U12e.20 drifts to investigate the geology of the Hybla Gold working point.

Mechanics of the Compression Wood Response: II. On the Location, Action, and Distribution of Compression Wood Formation.

PubMed

Archer, R R; Wilson, B F

1973-04-01

A new method for simulation of cross-sectional growth provided detailed information on the location of normal wood and compression wood increments in two tilted white pine (Pinus strobus L.) leaders. These data were combined with data on stiffness, slope, and curvature changes over a 16-week period to make the mechanical analysis. The location of compression wood changed from the under side to a flank side and then to the upper side of the leader as the geotropic stimulus decreased, owing to compression wood action. Its location shifted back to a flank side when the direction of movement of the leader reversed. A model for this action, based on elongation strains, was developed and predicted the observed curvature changes with elongation strains of 0.3 to 0.5%, or a maximal compressive stress of 60 to 300 kilograms per square centimeter. After tilting, new wood formation was distributed so as to maintain consistent strain levels along the leaders in bending under gravitational loads. The computed effective elastic moduli were about the same for the two leaders throughout the season.

Tensile and pack compressive tests of some sheets of aluminum alloy, 1025 carbon steel, and chromium-nickel steel

NASA Technical Reports Server (NTRS)

Atchison, C S; Miller, James A

1942-01-01

Tensile and compressive stress-strain curves, stress-deviation curves, and secant modulus-stress curves are given for longitudinal and transverse specimens of 17S-T, 24S-T, and 24S-RT aluminum-alloy sheet in thicknesses from 0.032 to 0.081 inch, 1025 carbon steel sheet in thicknesses of 0.054 and 0.120 inch, and chromium-nickel steel sheet in thicknesses form 0.020 to 0.0275 inch. Significant differences were found between the tensile and the compressive stress-strain curves, and also the corresponding corollary curves; similarly, differences were found between the curves for the longitudinal and transverse directions. These differences are of particular importance in considering the compressive strength of aircraft structures made of thin sheet. They are explored further for the case of compression by giving tangent modulus-stress curves in longitudinal and transverse compression and dimensionless curves of the ratio of tangent modulus to Young's modulus and of the ratio of reduced modulus for a rectangular section to Young's modulus, both plotted against the ratio of stress to secant yield strength.

Sediment drifts and contourites on the continental margin off northwest Britain

NASA Astrophysics Data System (ADS)

Stoker, M. S.; Akhurst, M. C.; Howe, J. A.; Stow, D. A. V.

1998-01-01

Seismic reflection profiles and short cores from the continental margin off northwest Britain have revealed a variety of sediment-drift styles and contourite deposits preserved in the northeast Rockall Trough and Faeroe-Shetland Channel. The sediment drifts include: (1) distinctly mounded elongate drifts, both single- and multi-crested; (2) broad sheeted drift forms, varying from gently domed to flat-lying; and (3) isolated patch drifts, including moat-related drifts. Fields of sediment waves are locally developed in association with the elongate and gently domed, broad sheeted drifts. The contrasting styles of the sediment drifts most probably reflect the interaction between a variable bottom-current regime and the complex bathymetry of the continental margin. The bulk of the mounded/gently domed drifts occur in the northeast Rockall Trough, whereas the flat-lying, sheet-form deposits occur in the Faeroe-Shetland Channel, a much narrower basin which appears to have been an area more of sediment export than drift accumulation. Patch drifts are present in both basins. In the northeast Rockall Trough, the along-strike variation from single- to multi-crested elongate drifts may be a response to bottom-current changes influenced by developing drift topography. Muddy, silty muddy and sandy contourites have been recovered in sediment cores from the uppermost parts of the drift sequences. On the basis of their glaciomarine origin, these mid- to high-latitude contourites can be referred to, collectively, as glacigenic contourites. Both partial and complete contourite sequences are preserved; the former consist largely of sandy (mid-only) and top-only contourites. Sandy contourites, by their coarse-grained nature and their formation under strongest bottom-current flows, are the most likely to be preserved in the rock record. However, the very large scale of sediment drifts should be borne in mind with regard to the recognition of fossil contourites in ancient successions.

DRIFT POTENTIAL OF TILTED SHIELDED ROTARY ATOMISERS BASED ON WIND TUNNEL MEASUREMENTS.

PubMed

Salah, S Ouled Taleb; Massinon, M; De Cock, N; Schiffers, B; Lebeau, F

2015-01-01

Crop protection is mainly achieved by applying Plant Protection Products (PPP) using hydraulic nozzles, which rely on pressure, to produce a wide droplet size distribution. Because of always increased concerns about drift reduction, a wider range of low drift nozzles, such as air induction nozzles, was adopted in order to reduce the finest part of the spray. While successful for some treatments, the efficiency of coarser sprays is dramatically reduced on small and superhydrophobic target, i.e. at early stage weed control. This may be related to the increased proportion of big bouncing and splashing droplets. On the other hand, Controlled Droplet Application (CDA), using shielded rotary atomizers, stands for an improved control of droplets diameters and trajectories compared to hydraulic nozzles. Unfortunately, these atomizers, because of their horizontal droplet release, are widely recognized to produce more drift than hydraulic nozzles. The present contribution investigates whether the setting of a rotary atomizer 60 degrees forward tilted can reduce drift to acceptable levels in comparison with vertical and 60 degrees forward tilted standard and low drift flat fan nozzles for the same flow rate. In a wind tunnel, the drift potential of a medium spray produced by a tilted shielded rotary atomizer Micromax 120 was benchmarked with that of a flat fan nozzle XR11002 fine spray and that of an anti-drift nozzle Hardi Injet 015 medium spray. Operating parameters were set to apply 0.56 l/min for every spray generator. Vertical drift profiles were measured 2.0 m downward from nozzle axis for a 2 m.s(-1) wind speed. The tilted hydraulic nozzles resulted in a significant drift increase while droplets trajectories are affected by the decrease of the droplet initial vertical speed. Droplets emitted by the shielded rotary atomizer drift due to low entrained air and turbulence. A significant reduction of the cumulative drift was achieved by the rotary atomizer in comparison with flat fan nozzle while still being higher than the anti-drift nozzle. Unfortunately, the drift potential index (DIX) revealed that the cumulative drift reduction may not results in actual drift decrease because of higher drift at higher sampling locations. As a result, the DIX of the shielded rotary atomizer was similar to the standard flat-fan nozzle while the anti-drift nozzle reduced drastically drift as intended. Therefore, the 60 degrees tilted rotary atomizer failed to reach low drift levels as expected despite the reduced span.

Farm-Level Effects of Soil Conservation and Commodity Policy Alternatives: Model and Data Documentation.

ERIC Educational Resources Information Center

Sutton, John D.

This report documents a profit-maximizing linear programming (LP) model of a farm typical of a major corn-soybean producing area in the Southern Michigan-Northern Indiana Drift Plain. Following an introduction, a complete description of the farm is provided. The next section presents the LP model, which is structured to help analyze after-tax…

CYCLOTRON-WAVE INSTABILITIES,

DTIC Science & Technology

Interactions of waves on electron streams or plasmas are studied for several geometric configurations of finite cross section in a finite magnetic...velocity parallel to the magnetic field. It is further assumed that either macroscopic neutrality exists or static spacecharge forces are negligible. For...the most part the quasi-static analysis is used. For the case of two drifting streams cyclotron waves act to giveinstabilities which are either

Adiabatic particle motion in a nearly drift-free magnetic field - Application to the geomagnetic tail

NASA Technical Reports Server (NTRS)

Stern, D. P.

1978-01-01

An investigation is made of the adiabatic particle motion occurring in an almost drift-free magnetic field. The dependence of the mean drift velocity on the equatorial pitch angle and the variation of the local drift velocity along the trajectories is studied. The fields considered are two-dimensional and resemble the geomagnetic tail. Derivations are presented for instantaneous and average drift velocities, bounce times, longitudinal invariants, and approximations to the adiabatic Hamiltonian. As expected, the mean drift velocity is significantly smaller than the instantaneous drift velocities found at typical points on the trajectory. The slow drift indicates that particles advance in the dawn-dusk direction rather slowly in the plasma sheet of the magnetospheric tail.

Adiabatic particle motion in a nearly drift-free magnetic field: Application to the geomagnetic tail

NASA Technical Reports Server (NTRS)

Stern, D. P.

1977-01-01

The guiding center motion of particles in a nearly drift free magnetic field is analyzed in order to investigate the dependence of mean drift velocity on equatorial pitch angle, the variation of local drift velocity along the trajectory, and other properties. The mean drift for adiabatic particles is expressed by means of elliptic integrals. Approximations to the twice-averaged Hamiltonian W near z = O are derived, permitting simple representation of drift paths if an electric potential also exists. In addition, the use of W or of expressions for the longitudinal invariant allows the derivation of the twice averaged Liouville equation and of the corresponding Vlasov equation. Bounce times are calculated (using the drift-free approximation), as are instantaneous guiding center drift velocities, which are then used to provide a numerical check on the formulas for the mean drift.

The Effects of Clock Drift on the Mars Exploration Rovers

NASA Technical Reports Server (NTRS)

Ali, Khaled S.; Vanelli, C. Anthony

2012-01-01

All clocks drift by some amount, and the mission clock on the Mars Exploration Rovers (MER) is no exception. The mission clock on both MER rovers drifted significantly since the rovers were launched, and it is still drifting on the Opportunity rover. The drift rate is temperature dependent. Clock drift causes problems for onboard behaviors and spacecraft operations, such as attitude estimation, driving, operation of the robotic arm, pointing for imaging, power analysis, and telecom analysis. The MER operations team has techniques to deal with some of these problems. There are a few techniques for reducing and eliminating the clock drift, but each has drawbacks. This paper presents an explanation of what is meant by clock drift on the rovers, its relationship to temperature, how we measure it, what problems it causes, how we deal with those problems, and techniques for reducing the drift.

Diel drift of Chironomidae larvae in a pristine Idaho mountain stream

USGS Publications Warehouse

Tilley, L.J.

1989-01-01

Simultaneous hourly net collections in a meadow and canyon reach of a mountain stream determined diel and spatial abundances of drifting Chironomidae larvae. Sixty-one taxa were identified to the lowest practical level, 52 in the meadow and 41 in the canyon. Orthocladiinae was the most abundant subfamily with 32 taxa and a 24 h mean density of 294 individuals 100 m-3 (meadow) and 26 taxa and a mean of 648 individuals 100 m-3 (canyon). Chironominae was the second most abundant subfamily. Nonchironomid invertebrates at both sites and total Chironomidae larvae (meadow) were predominantly night-drifting. Parakiefferiella and Psectrocladius were day-drifting (meadow) whereas 8 other chironomid taxa (meadow) and 2 taxa (canyon) were night-drifting. All others were aperiodic or too rare to test periodicity, Stempellinella cf brevis Edwards exhibited catastrophic drift in the canyon only. The different drift patterns between sites is attributed to greater loss of streambed habitat in the canyon compared to the meadow as streamflow decreased. Consequent crowding of chironomid larvae in the canyon caused catastrophic drift or interfered with drift periodicty. This study adds to knowledge of Chironomidae drift and shows influences on drift of hydrologic and geomorphic conditions. ?? 1989 Kluwer Academic Publishers.

An experimental test and models of drift and dispersal processes of pallid sturgeon (Scaphirhynchus albus) free embryos in the Missouri River

USGS Publications Warehouse

Braaten, P.J.; Fuller, D.B.; Lott, R.D.; Ruggles, M.P.; Brandt, T.F.; Legare, R.G.; Holm, R.J.

2012-01-01

Free embryos of wild pallid sturgeon Scaphirhynchus albus were released in the Missouri River and captured at downstream sites through a 180-km reach of the river to examine ontogenetic drift and dispersal processes. Free embryos drifted primarily in the fastest portion of the river channel, and initial drift velocities for all age groups (mean = 0.66–0.70 m s−1) were only slightly slower than mean water column velocity (0.72 m s−1). During the multi-day long-distance drift period, drift velocities of all age groups declined an average of 9.7% day−1. Younger free embryos remained in the drift upon termination of the study; whereas, older age groups transitioned from drifting to settling during the study. Models based on growth of free embryos, drift behavior, size-related variations in drift rates, and channel hydraulic characteristics were developed to estimate cumulative distance drifted during ontogenetic development through a range of simulated water temperatures and velocity conditions. Those models indicated that the average free embryo would be expected to drift several hundred km during ontogenetic development. Empirical data and model results highlight the long-duration, long-distance drift and dispersal processes for pallid sturgeon early life stages. In addition, results provide a likely mechanism for lack of pallid sturgeon recruitment in fragmented river reaches where dams and reservoirs reduce the length of free-flowing river available for pallid sturgeon free embryos during ontogenetic development.

In situ oil shale retort with a generally T-shaped vertical cross section

DOEpatents

Ricketts, Thomas E.

1981-01-01

An in situ oil shale retort is formed in a subterranean formation containing oil shale. The retort contains a fragmented permeable mass of formation particles containing oil shale and has a production level drift in communication with a lower portion of the fragmented mass for withdrawing liquid and gaseous products of retorting during retorting of oil shale in the fragmented mass. The principal portion of the fragmented mass is spaced vertically above a lower production level portion having a generally T-shaped vertical cross section. The lower portion of the fragmented mass has a horizontal cross sectional area smaller than the horizontal cross sectional area of the upper principal portion of the fragmented mass above the production level.

Diesel engine catalytic combustor system. [aircraft engines

NASA Technical Reports Server (NTRS)

Ream, L. W. (Inventor)

1984-01-01

A low compression turbocharged diesel engine is provided in which the turbocharger can be operated independently of the engine to power auxiliary equipment. Fuel and air are burned in a catalytic combustor to drive the turbine wheel of turbine section which is initially caused to rotate by starter motor. By opening a flapper value, compressed air from the blower section is directed to catalytic combustor when it is heated and expanded, serving to drive the turbine wheel and also to heat the catalytic element. To start, engine valve is closed, combustion is terminated in catalytic combustor, and the valve is then opened to utilize air from the blower for the air driven motor. When the engine starts, the constituents in its exhaust gas react in the catalytic element and the heat generated provides additional energy for the turbine section.

Travelling-wave ion mobility mass spectrometry and negative ion fragmentation of hybrid and complex N-glycans

PubMed Central

Harvey, David J.; Scarff, Charlotte A.; Edgeworth, Matthew; Pagel, Kevin; Thalassinos, Konstantinos; Struwe, Weston B.; Crispin, Max; Scrivens, Jim

2016-01-01

Nitrogen cross sections of hybrid and complex glycans released from the glycoproteins IgG, gp120 (from human immunodeficiency virus), ovalbumin, α1-acid glycoprotein, thyroglobulin and fucosylated glycoproteins from the human parotid gland were measured with a travelling-wave ion mobility mass spectrometer using dextran as the calibrant. The utility of this instrument for isomer separation was also investigated. Some isomers, such as Man3GlcNAc3 from chicken ovalbumin and Man3GlcNAc3Fuc1 from thyroglobulin could be partially resolved and identified by their negative ion fragmentation spectra. Several other larger glycans, however, although existing as isomers, produced only asymmetric rather than separated arrival time distributions (ATDs). Nevertheless, in these cases, isomers could often be detected by plotting extracted fragment ATDs of diagnostic fragment ions from the negative ion spectra obtained in the transfer cell of the Waters Synapt mass spectrometer. Coincidence in the drift times of all fragment ions with an overall asymmetric ATD profile usually suggested that separations were due to conformers or anomers, whereas symmetrical ATDs of fragments showing differences in drift times indicated isomer separation. Although some significant differences in cross sections were found for the smaller isomeric glycans, the differences found for the larger compounds were usually too small to be analytically useful. Possible correlations between cross sections and structural types were also investigated and it was found that complex glycans tended to have slightly smaller cross sections than high-mannose glycans of comparable molecular weight. In addition, biantennary glycans containing a core fucose and/or a bisecting GlcNAc residue fell on different mobility-m/z trend lines to those glycans not so substituted with both of these substituents contributing to larger cross sections. PMID:27477117

Effects of Visual Feedback and Memory on Unintentional Drifts in Performance During Finger Pressing Tasks

PubMed Central

Solnik, Stanislaw; Qiao, Mu; Latash, Mark L.

2017-01-01

This study tested two hypotheses on the nature of unintentional force drifts elicited by removing visual feedback during accurate force production tasks. The role of working memory (memory hypothesis) was explored in tasks with continuous force production, intermittent force production, and rest intervals over the same time interval. The assumption of unintentional drifts in referent coordinate for the fingertips was tested using manipulations of visual feedback: Young healthy subjects performed accurate steady-state force production tasks by pressing with the two index fingers on individual force sensors with visual feedback on the total force, sharing ratio, both, or none. Predictions based on the memory hypothesis have been falsified. In particular, we observed consistent force drifts to lower force values during continuous force production trials only. No force drift or drifts to higher forces were observed during intermittent force production trials and following rest intervals. The hypotheses based on the idea of drifts in referent finger coordinates have been confirmed. In particular, we observed superposition of two drift processes: A drift of total force to lower magnitudes and a drift of the sharing ratio to 50:50. When visual feedback on total force only was provided, the two finger forces showed drifts in opposite directions. We interpret the findings as evidence for the control of motor actions with changes in referent coordinates for participating effectors. Unintentional drifts in performance are viewed as natural relaxation processes in the involved systems; their typical time reflects stability in the direction of the drift. The magnitude of the drift was higher in the right (dominant) hand, which is consistent with the dynamic dominance hypothesis. PMID:28168396

On the utility of the ionosonde Doppler-derived EXB drift during the daytime

NASA Astrophysics Data System (ADS)

Joshi, L. M.; Sripathi, S.

2016-03-01

Vertical EXB drift measured using the ionosonde Doppler sounding during the daytime suffers from an underestimation of the actual EXB drift because the reflection height of the ionosonde signals is also affected by the photochemistry of the ionosphere. Systematic investigations have indicated a fair/good correlation to exist between the C/NOFS and ionosonde Doppler-measured vertical EXB drift during the daytime over magnetic equator. A detailed analysis, however, indicated that the linear relation between the ionosonde Doppler drift and C/NOFS EXB drift varied with seasons. Thus, solar, seasonal, and also geomagnetic variables were included in the Doppler drift correction, using the artificial neural network-based approach. The RMS error in the neural network was found to be smaller than that in the linear regression analysis. Daytime EXB drift was derived using the neural network which was also used to model the ionospheric redistribution in the SAMI2 model. SAMI2 model reproduced strong (weak) equatorial ionization anomaly (EIA) for cases when neural network corrected daytime vertical EXB drift was high (low). Similar features were also observed in GIM TEC maps. Thus, the results indicate that the neural network can be utilized to derive the vertical EXB drift from its proxies, like the ionosonde Doppler drift. These results indicate that the daytime ionosonde measured vertical EXB drift can be relied upon, provided that adequate corrections are applied to it.

Description of Primary Education 1st Grade Students' Forms of Holding a Pencil as well as Their Grip and Compression Strengths

ERIC Educational Resources Information Center

Temur, Turan

2011-01-01

This study aimed to examine how first grade students in primary education held and gripped a pencil and their compressive strength using a descriptive research method. The participants of the research comprises first grade students attending a private school in the city center of Ankara (n=79). All of the four different sections in this private…

Dynamic Recrystallization Kinetics of 690 Alloy During Hot Compression of Double-Cone Samples

NASA Astrophysics Data System (ADS)

Wang, Jue; Zhai, Shun-Chao

2017-03-01

Hot compression tests of double-cone samples were conducted for 690 alloy to study the kinetic behavior of the complete dynamic recrystallization (DRX) process under low deformation temperatures from 960 to 1080 °C. The microstructure of 82 points in the vertical section of every deformed sample was quantitatively analyzed to determine the DRX fraction. Corresponding strain of these points was calculated by finite element simulations. Kinetic curves of the specimens with different preheating temperatures were then constructed. The features of various boundaries with different misorientation angles were investigated by electron backscatter diffraction technology and transmission electron microscope. The results showed that the strain is continuously and symmetrically distributed along the centerline of the vertical section. Large strain of 1.84 was obtained when the compression amount is 12 mm for double-cone samples. All the fitted kinetic curves display an "S" type, which possess a low growth rate of DRX at the beginning and the end of compression. The critical strain of recrystallization decreases with the increase in preheating temperature, while the completion strain remains around 1.5 for all the samples. The initial and maximum growth rates of DRX fraction have the opposite trend with the change in temperature, which is considered to be attributed to the behaviors of different misorientation boundaries.

User Guide for Compressible Flow Toolbox Version 2.1 for Use With MATLAB(Registered Trademark); Version 7

NASA Technical Reports Server (NTRS)

Melcher, Kevin J.

2006-01-01

This report provides a user guide for the Compressible Flow Toolbox, a collection of algorithms that solve almost 300 linear and nonlinear classical compressible flow relations. The algorithms, implemented in the popular MATLAB programming language, are useful for analysis of one-dimensional steady flow with constant entropy, friction, heat transfer, or shock discontinuities. The solutions do not include any gas dissociative effects. The toolbox also contains functions for comparing and validating the equation-solving algorithms against solutions previously published in the open literature. The classical equations solved by the Compressible Flow Toolbox are: isentropic-flow equations, Fanno flow equations (pertaining to flow of an ideal gas in a pipe with friction), Rayleigh flow equations (pertaining to frictionless flow of an ideal gas, with heat transfer, in a pipe of constant cross section.), normal-shock equations, oblique-shock equations, and Prandtl-Meyer expansion equations. At the time this report was published, the Compressible Flow Toolbox was available without cost from the NASA Software Repository.

Seasonal drift and feeding periodicity during summer of the amphipod, Gammarus psuedolimnaeus

USGS Publications Warehouse

Johnson, James H.

2014-01-01

Downstream drift of aquatic invertebrates is an important ecological process that varies temporally. Seasonal patterns of diel drift and diel feeding periodicity during summer of the amphipod Gammarus pseudolimnaeus were examined in a small stream in central New York. Seasonal trends in drift were similar with peak drift occurring from 2000 to 0400 h. Very little drift occurred during the day. Feeding intensity of G. pseudolimnaeus was greatest from 2000 to 0400 h and was significantly greater than at 0400 to 0800 h and 0800 to 1200 h. Previous research on feeding periodicity of this species found no evidence of periods of increased food consumption. Conflicting results between this study and earlier studies may be due to sampling drifting versus non-drifting amphipods.

Intrafractional baseline drift during free breathing breast cancer radiation therapy.

PubMed

Jensen, Christer Andre; Acosta Roa, Ana María; Lund, Jo-Åsmund; Frengen, Jomar

2017-06-01

Intrafraction motion in breast cancer radiation therapy (BCRT) has not yet been thoroughly described in the literature. It has been observed that baseline drift occurs as part of the intrafraction motion. This study aims to measure baseline drift and its incidence in free-breathing BCRT patients using an in-house developed laser system for tracking the position of the sternum. Baseline drift was monitored in 20 right-sided breast cancer patients receiving free breathing 3D-conformal RT by using an in-house developed laser system which measures one-dimensional distance in the AP direction. A total of 357 patient respiratory traces from treatment sessions were logged and analysed. Baseline drift was compared to patient positioning error measured from in-field portal imaging. The mean overall baseline drift at end of treatment sessions was -1.3 mm for the patient population. Relatively small baseline drift was observed during the first fraction; however it was clearly detected already at the second fraction. Over 90% of the baseline drift occurs during the first 3 min of each treatment session. The baseline drift rate for the population was -0.5 ± 0.2 mm/min in the posterior direction the first minute after localization. Only 4% of the treatment sessions had a 5 mm or larger baseline drift at 5 min, all towards the posterior direction. Mean baseline drift in the posterior direction in free breathing BCRT was observed in 18 of 20 patients over all treatment sessions. This study shows that there is a substantial baseline drift in free breathing BCRT patients. No clear baseline drift was observed during the first treatment session; however, baseline drift was markedly present at the rest of the sessions. Intrafraction motion due to baseline drift should be accounted for in margin calculations.

“How Did We Get Here?”: Topic Drift in Online Health Discussions

PubMed Central

Hartzler, Andrea L; Huh, Jina; Hsieh, Gary; McDonald, David W; Pratt, Wanda

2016-01-01

Background Patients increasingly use online health communities to exchange health information and peer support. During the progression of health discussions, a change of topic—topic drift—can occur. Topic drift is a frequent phenomenon linked to incoherence and frustration in online communities and other forms of computer-mediated communication. For sensitive topics, such as health, such drift could have life-altering repercussions, yet topic drift has not been studied in these contexts. Objective Our goals were to understand topic drift in online health communities and then to develop and evaluate an automated approach to detect both topic drift and efforts of community members to counteract such drift. Methods We manually analyzed 721 posts from 184 threads from 7 online health communities within WebMD to understand topic drift, members’ reaction towards topic drift, and their efforts to counteract topic drift. Then, we developed an automated approach to detect topic drift and counteraction efforts. We detected topic drift by calculating cosine similarity between 229,156 posts from 37,805 threads and measuring change of cosine similarity scores from the threads’ first posts to their sequential posts. Using a similar approach, we detected counteractions to topic drift in threads by focusing on the irregular increase of similarity scores compared to the previous post in threads. Finally, we evaluated the performance of our automated approaches to detect topic drift and counteracting efforts by using a manually developed gold standard. Results Our qualitative analyses revealed that in threads of online health communities, topics change gradually, but usually stay within the global frame of topics for the specific community. Members showed frustration when topic drift occurred in the middle of threads but reacted positively to off-topic stories shared as separate threads. Although all types of members helped to counteract topic drift, original posters provided the most effort to keep threads on topic. Cosine similarity scores show promise for automatically detecting topical changes in online health discussions. In our manual evaluation, we achieved an F1 score of .71 and .73 for detecting topic drift and counteracting efforts to stay on topic, respectively. Conclusions Our analyses expand our understanding of topic drift in a health context and highlight practical implications, such as promoting off-topic discussions as a function of building rapport in online health communities. Furthermore, the quantitative findings suggest that an automated tool could help detect topic drift, support counteraction efforts to bring the conversation back on topic, and improve communication in these important communities. Findings from this study have the potential to reduce topic drift and improve online health community members’ experience of computer-mediated communication. Improved communication could enhance the personal health management of members who seek essential information and support during times of difficulty. PMID:27806924

Primary and secondary pesticide drift profiles from a peach orchard.

PubMed

Zivan, Ohad; Bohbot-Raviv, Yardena; Dubowski, Yael

2017-06-01

Atmospheric drift is considered a major loss path of pesticide from target areas, but there is still a large gap of knowledge regarding this complex phenomenon. Pesticide drift may occur during application (Primary drift) and after it (Secondary drift). The present study focuses on primary and secondary drift from ground applications in peach orchard (tree height of 3 m), under Mediterranean climate. Detailed and prolonged vertical drift profiles at close proximity to orchard are presented, together with detailed measurements of key meteorological parameters. The effect of volatility on drift was also studied by simultaneously applying two pesticides that differ in their volatility. Drifting airborne pesticides were detected both during and after applications at sampling distances of 7 and 20 m away from orchard edge. Concentrations ranged between hundreds ng m -3 to a few μg m -3 and showed clear decrease with time and with upwind conditions. Almost no decline in concentrations with height was observed up to thrice canopy height (i.e., 10 m). These homogeneous profiles indicate strong mixing near orchard and are in line with the unstable atmospheric conditions that prevailed during measurements. While air concentrations during pesticide application were higher than after it, overall pesticide load drifted from the orchard during primary and secondary drift are comparable. To the best of our knowledge this is the first work to show such large vertical dispersion and long duration of secondary drift following ground application in orchards. The obtained information indicates that secondary drift should not be neglected in exposure and environmental impact estimations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dogmas and controversies in compression therapy: report of an International Compression Club (ICC) meeting, Brussels, May 2011.

PubMed

Flour, Mieke; Clark, Michael; Partsch, Hugo; Mosti, Giovanni; Uhl, Jean-Francois; Chauveau, Michel; Cros, Francois; Gelade, Pierre; Bender, Dean; Andriessen, Anneke; Schuren, Jan; Cornu-Thenard, André; Arkans, Ed; Milic, Dragan; Benigni, Jean-Patrick; Damstra, Robert; Szolnoky, Gyozo; Schingale, Franz

2013-10-01

The International Compression Club (ICC) is a partnership between academics, clinicians and industry focused upon understanding the role of compression in the management of different clinical conditions. The ICC meet regularly and from these meetings have produced a series of eight consensus publications upon topics ranging from evidence-based compression to compression trials for arm lymphoedema. All of the current consensus documents can be accessed on the ICC website (http://www.icc-compressionclub.com/index.php). In May 2011, the ICC met in Brussels during the European Wound Management Association (EWMA) annual conference. With almost 50 members in attendance, the day-long ICC meeting challenged a series of dogmas and myths that exist when considering compression therapies. In preparation for a discussion on beliefs surrounding compression, a forum was established on the ICC website where presenters were able to display a summary of their thoughts upon each dogma to be discussed during the meeting. Members of the ICC could then provide comments on each topic thereby widening the discussion to the entire membership of the ICC rather than simply those who were attending the EWMA conference. This article presents an extended report of the issues that were discussed, with each dogma covered in a separate section. The ICC discussed 12 'dogmas' with areas 1 through 7 dedicated to materials and application techniques used to apply compression with the remaining topics (8 through 12) related to the indications for using compression. © 2012 The Authors. International Wound Journal © 2012 John Wiley & Sons Ltd and Medicalhelplines.com Inc.

Radar studies of midlatitude ionospheric plasma drifts

NASA Astrophysics Data System (ADS)

Scherliess, L.; Fejer, B. G.; Holt, J.; Goncharenko, L.; Amory-Mazaudier, C.; Buonsanto, M. J.

2001-02-01

We use incoherent scatter radar measurements from Millstone Hill and Saint Santin to study the midlatitude F region electrodynamic plasma drifts during geomagnetically quiet and active periods. We present initially a local time, season, and solar flux dependent analytical model of the quiet time zonal and meridional E×B drifts over these stations. We discuss, for the first time, the Saint Santin drift patterns during solar maximum. We have used these quiet time models to extract the geomagnetic perturbation drifts which were modeled as a function of the time history of the auroral electrojet indices. Our results illustrate the evolution of the disturbance drifts driven by the combined effects of prompt penetration and longer lasting perturbation electric fields. The meridional electrodynamic disturbance drifts have largest amplitudes in the midnight-noon sector. The zonal drifts are predominantly westward, with largest amplitudes in the dusk-midnight sector and, following a decrease in the high-latitude convection, they decay more slowly than the meridional drifts. The prompt penetration and steady state zonal disturbance drifts derived from radar measurements are in good agreement with results obtained from both the ion drift meter data on board the Dynamics Explorer 2 (DE 2) satellite and from the Rice Convection Model.

Bunch compression efficiency of the femtosecond electron source at Chiang Mai University

NASA Astrophysics Data System (ADS)

Thongbai, C.; Kusoljariyakul, K.; Saisut, J.

2011-07-01

A femtosecond electron source has been developed at the Plasma and Beam Physics Research Facility (PBP), Chiang Mai University (CMU), Thailand. Ultra-short electron bunches can be produced with a bunch compression system consisting of a thermionic cathode RF-gun, an alpha-magnet as a magnetic bunch compressor, and a linear accelerator as a post acceleration section. To obtain effective bunch compression, it is crucial to provide a proper longitudinal phase-space distribution at the gun exit matched to the subsequent beam transport system. Via beam dynamics calculations and experiments, we investigate the bunch compression efficiency for various RF-gun fields. The particle distribution at the RF-gun exit will be tracked numerically through the alpha-magnet and beam transport. Details of the study and results leading to an optimum condition for our system will be presented.

Development of turbomachinery trains for the CASHING, NGCASH, and IGCASH cycle applications: Final report

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

Gaul, G.; Nakhamkin, M.; Swensen, E.

1994-12-01

Turbomachinery trains were conceptually developed for three power plant concepts: Compressed Air Storage with Humidification and Integrated Gasification and Natural Gas Firing (CASHING), Natural Gas fired Compressed Air Storage with Humidification (NGCASH), and Integrated Gasification fired Compressed Air Storage with Humidification (IGCASH). Performance data, arrangement drawings, cost estimates, and other technical information for the three turboexpander trains were developed based on the Westinghouse BB51 steam turbine for the high pressure expander and the expander section of the W501F or W501D5 combustion turbine for the low pressure expander. The study supports previous EPRI projects investigating the performance and cost of CASHING,more » NGCASH, and IGCASH concepts and provides a basis for quotations that can be used in evaluating compressed air energy storage concepts in future projects.« less

"How Did We Get Here?": Topic Drift in Online Health Discussions.

PubMed

Park, Albert; Hartzler, Andrea L; Huh, Jina; Hsieh, Gary; McDonald, David W; Pratt, Wanda

2016-11-02

Patients increasingly use online health communities to exchange health information and peer support. During the progression of health discussions, a change of topic-topic drift-can occur. Topic drift is a frequent phenomenon linked to incoherence and frustration in online communities and other forms of computer-mediated communication. For sensitive topics, such as health, such drift could have life-altering repercussions, yet topic drift has not been studied in these contexts. Our goals were to understand topic drift in online health communities and then to develop and evaluate an automated approach to detect both topic drift and efforts of community members to counteract such drift. We manually analyzed 721 posts from 184 threads from 7 online health communities within WebMD to understand topic drift, members' reaction towards topic drift, and their efforts to counteract topic drift. Then, we developed an automated approach to detect topic drift and counteraction efforts. We detected topic drift by calculating cosine similarity between 229,156 posts from 37,805 threads and measuring change of cosine similarity scores from the threads' first posts to their sequential posts. Using a similar approach, we detected counteractions to topic drift in threads by focusing on the irregular increase of similarity scores compared to the previous post in threads. Finally, we evaluated the performance of our automated approaches to detect topic drift and counteracting efforts by using a manually developed gold standard. Our qualitative analyses revealed that in threads of online health communities, topics change gradually, but usually stay within the global frame of topics for the specific community. Members showed frustration when topic drift occurred in the middle of threads but reacted positively to off-topic stories shared as separate threads. Although all types of members helped to counteract topic drift, original posters provided the most effort to keep threads on topic. Cosine similarity scores show promise for automatically detecting topical changes in online health discussions. In our manual evaluation, we achieved an F1 score of .71 and .73 for detecting topic drift and counteracting efforts to stay on topic, respectively. Our analyses expand our understanding of topic drift in a health context and highlight practical implications, such as promoting off-topic discussions as a function of building rapport in online health communities. Furthermore, the quantitative findings suggest that an automated tool could help detect topic drift, support counteraction efforts to bring the conversation back on topic, and improve communication in these important communities. Findings from this study have the potential to reduce topic drift and improve online health community members' experience of computer-mediated communication. Improved communication could enhance the personal health management of members who seek essential information and support during times of difficulty. ©Albert Park, Andrea L Hartzler, Jina Huh, Gary Hsieh, David W McDonald, Wanda Pratt. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 02.11.2016.

Construction and Gluing of G10 Frames and Printed Circuit Boards to be used in COMPASS Drift Chamber 5

NASA Astrophysics Data System (ADS)

Britto, Vivek

2014-09-01

COMPASS is a fixed-target nuclear physics experiment at CERN which explores the internal structure of the proton. One specific area of research is the measurement of single transverse spin asymmetries in pion beam induced Drell-Yan production of muon pairs from polarized proton targets. The spin dependence of the Drell-Yan cross section may be indicative of contributions from quark orbital angular momentum to the spin of the proton. The University of Illinois at Urbana-Champaign (UIUC), in collaboration with institutes in Taiwan, France, Italy and Germany, is designing and building a new drift chamber, DC5, to replace an aging detector in the COMPASS spectrometer. The frames supporting the anode wires and cathode planes in DC5 are constructed from G10, a fiberglass-epoxy composite. Once the individual sides of each frame have been milled, they are glued together at the corner lap joints. Additionally, printed circuit boards are glued to the anode frames, where sense and field wires will later be soldered. To maintain optimal operation of the drift chamber, the frame thickness after gluing must be within 50 μm of the design value. This presentation will explain the methods employed to achieve the required tolerances for this precision gluing process.

Linear and Nonlinear Coupling of Electrostatic Drift and Acoustic Perturbations in a Nonuniform Bi-Ion Plasma with Non-Maxwellian Electrons

NASA Astrophysics Data System (ADS)

Ali, Gul-e.; Ahmad, Ali; Masood, W.; Mirza, Arshad M.

2017-12-01

Linear and nonlinear coupling of drift and ion acoustic waves are studied in a nonuniform magnetized plasma comprising of Oxygen and Hydrogen ions with nonthermal distribution of electrons. It has been observed that different ratios of ion number densities and kappa and Cairns distributed electrons significantly modify the linear dispersion characteristics of coupled drift-ion acoustic waves. In the nonlinear regime, KdV (for pure drift waves) and KP (for coupled drift-ion acoustic waves) like equations have been derived to study the nonlinear evolution of drift solitary waves in one and two dimensions. The dependence of drift solitary structures on different ratios of ion number densities and nonthermal distribution of electrons has also been explored in detail. It has been found that the ratio of the diamagnetic drift velocity to the velocity of the nonlinear structure determines the existence regimes for the drift solitary waves. The present investigation may be beneficial to understand the formation of solitons in the ionospheric F-region.

Discovery of remarkable subpulse drifting pattern in PSR B0818-41

NASA Astrophysics Data System (ADS)

Bhattacharyya, B.; Gupta, Y.; Gil, J.; Sendyk, M.

The study of pulsars showing systematic subpulse drift patterns provides important clues for understanding of pulsar emission mechanism. Pulsars with wide profiles provide extra insights because of the presence of multiple drift bands (e.g PSR B0826-34). We report the discovery of a remarkable subpulse drift pattern in a relatively less studied wide profile pulsar, PSR B0818-41, using the GMRT. We find simultaneous occurrence of three drift regions with two drift rates, an inner region with steeper apparent drift rate flanked on each side by a region of slower apparent drift rate. Furthermore, the two closely spaced drift regions always maintain a constant phase relationship. These unique drift properties seen for this pulsar is very rare. We interpret that the observed drift pattern is created by intersection of our line of sight (LOS) with two conal rings in a inner LOS (negative beta) geometry. We argue that the carousel rotation periodicity (P_4) and the number of sparks (N_sp) are the same for the rings and claim that P_4 is close to the measured P_3. Based on our analysis results and interpretations, we simulate the radiation from B0818-41. The simulations support our interpretations and reproduce the average profile and the observed drift pattern. The results of our study show that PSR B0818-41 is a powerful system to explore the pulsar radio emission mechanism, the implications of which are also discussed in our work.

On the utility of the ionosonde Doppler derived EXB drift during the daytime

NASA Astrophysics Data System (ADS)

Mohan Joshi, Lalit; Sripathi, Samireddipelle

2016-07-01

Vertical EXB drift measured using the ionosonde Doppler sounding during the daytime suffers from an underestimation of the actual EXB drift. This is due to the photochemistry that determines the height of the F layer during the daytime, in addition to the zonal electric field. Systematic investigations have indicated a fair/good correlation to exist between the C/NOFS and ionosonde Doppler measured vertical EXB drift during the daytime over magnetic equator. A detailed analysis, however, indicated that the linear relation between the ionosonde Doppler drift and C/NOFS EXB drift varied with seasons. Thus, solar, seasonal and also geomagnetic variables were included in the Doppler drift correction, using the artificial neural network based approach. The RMS error in the neural network was found to be lesser than that in the linear regression analysis. Daytime EXB drift was derived using the neural network which was also used to model the ionospheic redistribution in the SAMI2 model. SAMI2 model reproduced strong (/weak) equatorial ionization anomaly (EIA) for cases when neural network corrected daytime vertical EXB drift was high (/low). Similar features were also observed in GIM TEC maps. Thus, the results indicate that the neural network can be utilized to derive the vertical EXB drift from its proxies, like the ionosonde Doppler drift. These results indicate that the daytime ionosonde measured vertical EXB drift can be relied upon, provided adequate corrections are applied to it.

Effects of roughness and compressibility of flooring on cow locomotion.

PubMed

Rushen, J; de Passillé, A M

2006-08-01

We examined the effects of roughness and degree of compressibility of flooring on the locomotion of dairy cows. We observed 16 cows walking down specially constructed walkways with materials that differed in surface roughness and degree of compressibility. Use of a commercially available soft rubber flooring material decreased slipping, number of strides, and time to traverse the corridor. These effects were most apparent at difficult sections of the corridor, such as at the start, at a right-angle turn, and across a gutter. Covering the walkway with a thin layer of slurry increased frequency of slipping, number of strides, and time taken to traverse the walkway. Effects of adding slurry were not overcome by increasing surface roughness or compressibility. Placing more compressible materials under a slip-resistant material reduced the time and number of steps needed to traverse the corridor but did not reduce slips, and the effects on cow locomotion varied nonlinearly with the degree of compressibility of the floor. Use of commercially available rubber floors improved cow locomotion compared with concrete floors. However, standard engineering measures of the floor properties may not predict effects of the floor on cow behavior well. Increasing compressibility of the flooring on which cows walk, independently of the roughness of the surface, can improve cow locomotion.

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

Neuffer, David; Snopok, Pavel; Alexahin, Yuri

A neutrino factory or muon collider requires the capture and cooling of a large number of muons. Scenarios for capture, bunching, phase-energy rotation and initial cooling of μ’s produced from a proton source target have been developed, initially for neutrino factory scenarios. They require a drift section from the target, a bunching section and a Φ-δE rotation section leading into the cooling channel. Important concerns are rf limitations within the focusing magnetic fields and large losses in the transport. The currently preferred cooling channel design is an “HFOFO Snake” configuration that cools both μ + and μ - transversely andmore » longitudinally. Finally, the status of the design is presented and variations are discussed.« less

Front End for a neutrino factory or muon collider

NASA Astrophysics Data System (ADS)

Neuffer, D.; Snopok, P.; Alexahin, Y.

2017-11-01

A neutrino factory or muon collider requires the capture and cooling of a large number of muons. Scenarios for capture, bunching, phase-energy rotation and initial cooling of μ 's produced from a proton source target have been developed, initially for neutrino factory scenarios. They require a drift section from the target, a bunching section and a varphi -δ E rotation section leading into the cooling channel. Important concerns are rf limitations within the focusing magnetic fields and large losses in the transport. The currently preferred cooling channel design is an "HFOFO Snake" configuration that cools both μ+ and μ- transversely and longitudinally. The status of the design is presented and variations are discussed.

Gyrophase drifts and the orbital evolution of dust at Jupiter's Gossamer Ring

NASA Technical Reports Server (NTRS)

Northrop, T. G.; Mendis, D. A.; Schaffer, Les

1989-01-01

The 'gyrophase drift' phenomenon in Jupiter's fine-dust 'gossamer ring' is presently shown to exceed the plasma-drag drift, and may be able to move small, charged grains either toward or away from synchronous radius. The grain gyrophase drifts toward the higher temperature in the presence of a radial gradient in plasma temperature; gyrophase drift will also occur in conjunction with a radial gradient in the relative concentrations of different plasma ion species, or even due to plasma-grain velocity variation associated with the grain's cycloidal motion through the plasma. The Poynting-Robertson drift is noted to be diminutive by comparison with either the plasma-drag or gyrophase drifts.

The physical and mechanical properties of treated and untreated Gigantochloa Scortechinii bamboo

NASA Astrophysics Data System (ADS)

Daud, Norhasliya Mohd; Nor, Norazman Mohamad; Yusof, Mohammed Alias; Bakhri, Azrul Affandhi Mustaffa Al; Shaari, Amalina Aisyah

2018-02-01

Bamboo's advantages such as fast growing, renewable and easily available raw material meets the demand of sustainable material in construction. Bamboo act as reinforcement to enhance strength in structural members. This paper investigated on the properties of Gigantochloa Scortechinii bamboo (moisture content, density, compression, shear and bending) by referring to ISO 22157. Moisture content for both untreated and treated bamboo high at the bottom section while density is high at the top section. Compression strength for untreated bamboo were between 19.96 to 23.80 MPa and treated bamboo were between 31.74 to 36.60 MPa. High compression was at the top section which have the greatest wall thickness. Shear strength recorded between 4.28 to 5.69 MPa for untreated bamboo with node and 3.67 to 5.21 MPa for treated bamboo with node. The shear strength of samples with node recorded high strength compared to internode. Untreated bamboo recorded the MOR between 53.64 to 73.66 MPa and 58.23 to 62.86 MPa for treated bamboo. MOE of untreated bamboo were between 26.70 GPa to 36.31 GPa while treated bamboo were between 28.83 to 33.41 GPa. By replacing bamboo to the conventional building material, cost of materials will be reduced and sustainability will be enhanced.

The Genetic Drift Inventory: A Tool for Measuring What Advanced Undergraduates Have Mastered about Genetic Drift

ERIC Educational Resources Information Center

Price, Rebecca M.; Andrews, Tessa C.; McElhinny, Teresa L.; Mead, Louise S.; Abraham, Joel K.; Thanukos, Anna; Perez, Kathryn E.

2014-01-01

Understanding genetic drift is crucial for a comprehensive understanding of biology, yet it is difficult to learn because it combines the conceptual challenges of both evolution and randomness. To help assess strategies for teaching genetic drift, we have developed and evaluated the Genetic Drift Inventory (GeDI), a concept inventory that measures…

Offshore platform structure intended to be installed in arctic waters, subjected to drifting icebergs

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

Kure, G.; Jenssen, D.N.; Naesje, K.

1984-09-11

An offshore platform structure, particularly intended to be installed in waters where drifting iceberg frequently appear, the platform structure being intended to be founded in a sea bed and comprises a substructure, a superstructure rigidly affixed to the substructure and extending vertically up above the sea level supporting a deck superstructure at its upper end. The horizontal cross-sectional area of the substructure is substantially greater than tath of the superstructure. The substructure rigidly supports a fender structure, the fender structure comprising an outer peripherally arranged wall and an inner cylindrical wall the inner and outer wall being rigidly interconnected bymore » means of a plurality of vertical and/or horizontal partition walls, dividing the fender structure into a plurality of cells or compartlents. The fender structure is arranged in spaced relation with respect to the superstructure.« less

Wind and tidal forcing of a buoyant plume, Mobile Bay, Alabama

USGS Publications Warehouse

Stumpf, R.P.; Gelfenbaum, G.; Pennock, J.R.

1993-01-01

AVHRR satellite imagery and in situ observations were combined to study the motion of a buoyant plume at the mouth of Mobile Bay, Alabama. The plume extended up to 30 km from shore, with a thickness of about 1 m. The inner plume, which was 3-8 m thick, moved between the Bay and inner shelf in response to tidal forcing. The tidal prism could be identified through the movement of plume waters between satellite images. The plume responded rapidly to alongshore wind, with sections of the plume moving at speeds of more than 70 cm s-1, about 11% of the wind speed. The plume moved predominantly in the direction of the wind with a weak Ekman drift. The enhanced speed of the plume relative to normal surface drift is probably due to the strong stratification in the plume, which limits the transfer of momentum into the underlying ambient waters. ?? 1993.

Grain boundary grooving induced by the anisotropic surface drift diffusion driven by the capillary and electromigration forces: Simulations

NASA Astrophysics Data System (ADS)

Akyildiz, Oncu; Omer Ogurtani, Tarik

2011-08-01

The morphological evolution kinetics of a bicrystal thin film induced by anisotropic surface drift diffusion and driven by the applied electrostatic field is investigated via self consistent dynamical computer simulations. The physico-mathematical model, which is based upon the irreversible thermodynamic treatment of surfaces and interfaces with singularities [T. O. Ogurtani, J. Chem. Phys. 124, 144706 (2006)], provided us with auto-control on the otherwise free-motion of the triple junction at the intersection of the grooving surface and the grain boundary, without having any a priori assumption on the equilibrium dihedral angles. The destruction of the symmetry of the freshly formed grain boundary grooves under the anisotropic surface diffusion driven by the concurrent action of the capillarity and electromigration is observed. After prolonged exposure times the applied electric field above the well defined threshold level modifies Mullins' familiar stationary state time law as, t¯1/4, and causes the premature termination of the groove penetration because of the current crowding at the tips of counteracting grain boundary-grooves initiated on both sides of the test modulus. That finding indicates that the electromigration plays the same role as a healing agent [T. O. Ogurtani, J. Appl. Phys. 106, 053503 (2009)] in arresting the thermal grooving, thereby avoiding the premature interconnect failure as in the case of surface roughening and crack initiation caused by compressive stress gradients. The role of the electromigration and wetting parameter on the ridge/slit formations are thoroughly investigated in this study and the prerequisite conditions are also identified.

Spatio-temporal evolution of the non-resonant instability in shock precursors of young supernova remnants

NASA Astrophysics Data System (ADS)

Kobzar, Oleh; Niemiec, Jacek; Pohl, Martin; Bohdan, Artem

2017-08-01

A non-resonant cosmic ray (CR) current-driven instability may operate in the shock precursors of young supernova remnants and be responsible for magnetic-field amplification, plasma heating and turbulence. Earlier simulations demonstrated magnetic-field amplification, and in kinetic studies a reduction of the relative drift between CRs and thermal plasma was observed as backreaction. However, all published simulations used periodic boundary conditions, which do not account for mass conservation in decelerating flows and only allow the temporal development to be studied. Here we report results of fully kinetic particle-in-cell simulations with open boundaries that permit inflow of plasma on one side of the simulation box and outflow at the other end, hence allowing an investigation of both the temporal and the spatial development of the instability. Magnetic-field amplification proceeds as in studies with periodic boundaries and, observed here for the first time, the reduction of relative drifts causes the formation of a shock-like compression structure at which a fraction of the plasma ions are reflected. Turbulent electric field generated by the non-resonant instability inelastically scatters CRs, modifying and anisotropizing their energy distribution. Spatial CR scattering is compatible with Bohm diffusion. Electromagnetic turbulence leads to significant non-adiabatic heating of the background plasma maintaining bulk equipartition between ions and electrons. The highest temperatures are reached at sites of large-amplitude electrostatic fields. Ion spectra show supra-thermal tails resulting from stochastic scattering in the turbulent electric field. Together, these modifications in the plasma flow will affect the properties of the shock and particle acceleration there.

Global Structure and Sodium Ion Dynamics in Mercury's Magnetosphere With the Offset Dipole

NASA Astrophysics Data System (ADS)

Yagi, M.; Seki, K.; Matsumoto, Y.; Delcourt, D. C.; Leblanc, F.

2017-11-01

We conducted global magnetohydrodynamics (MHD) simulation of Mercury's magnetosphere with the dipole offset, which was revealed by MESSENGER (Mercury Surface, Space Environment, Geochemistry, and Ranging) observations, in order to investigate its global structure under northward interplanetary magnetic field conditions. Sodium ion dynamics originating from the Mercury's exosphere is also investigated based on statistical trajectory tracing in the electric and magnetic fields obtained from the MHD simulations. The results reveal a north-south asymmetry characterized by open field lines around the southern polar region and northward deflection of the plasma sheet in the far tail. The asymmetry of magnetic field structure near the planet drastically affects trajectories of sodium ion and thus their pressure distributions and precipitation pattern onto the planet. Weaker magnetic field strength in the southern hemisphere than in the north increases ion loss by precipitation onto the planetary surface in the southern hemisphere. The "sodium ring," which is formed by high-energy sodium ions drifting around the planet, is also found in the vicinity of the planet. The sodium ring is almost circular under nominal solar wind conditions. The ring becomes partial under high solar wind density, because dayside magnetosphere is so compressed that there is no space for the sodium ions to drift around. In both cases, the sodium ring is formed by sodium ions that are picked up, accelerated in the magnetosheath just outside the magnetopause, and reentered into the magnetosphere due to combined effects of finite Larmor radius and convection electric field in the dawnside magnetosphere.

Physical mechanism causing rapid changes in ultrarelativistic electron pitch angle distributions right after a shock arrival: Evaluation of an electron dropout event

NASA Astrophysics Data System (ADS)

Zhang, X.-J.; Li, W.; Thorne, R. M.; Angelopoulos, V.; Ma, Q.; Li, J.; Bortnik, J.; Nishimura, Y.; Chen, L.; Baker, D. N.; Reeves, G. D.; Spence, H. E.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Blake, J. B.; Fennell, J. F.

2016-09-01

Three mechanisms have been proposed to explain relativistic electron flux depletions (dropouts) in the Earth's outer radiation belt during storm times: adiabatic expansion of electron drift shells due to a decrease in magnetic field strength, magnetopause shadowing and subsequent outward radial diffusion, and precipitation into the atmosphere (driven by EMIC wave scattering). Which mechanism predominates in causing electron dropouts commonly observed in the outer radiation belt is still debatable. In the present study, we evaluate the physical mechanism that may be primarily responsible for causing the sudden change in relativistic electron pitch angle distributions during a dropout event observed by Van Allen Probes during the main phase of the 27 February 2014 storm. During this event, the phase space density of ultrarelativistic (>1 MeV) electrons was depleted by more than 1 order of magnitude over the entire radial extent of the outer radiation belt (3 < L* < 5) in less than 6 h after the passage of an interplanetary shock. We model the electron pitch angle distribution under a compressed magnetic field topology based on actual solar wind conditions. Although these ultrarelativistic electrons exhibit highly anisotropic (peaked in 90°), energy-dependent pitch angle distributions, which appear to be associated with the typical EMIC wave scattering, comparison of the modeled electron distribution to electron measurements indicates that drift shell splitting is responsible for this rapid change in electron pitch angle distributions. This further indicates that magnetopause loss is the predominant cause of the electron dropout right after the shock arrival.

3D late gadolinium enhancement in a single prolonged breath-hold using supplemental oxygenation and hyperventilation.

PubMed

Roujol, Sébastien; Basha, Tamer A; Akçakaya, Mehmet; Foppa, Murilo; Chan, Raymond H; Kissinger, Kraig V; Goddu, Beth; Berg, Sophie; Manning, Warren J; Nezafat, Reza

2014-09-01

To evaluate the feasibility of three-dimensional (3D) single breath-hold late gadolinium enhancement (LGE) of the left ventricle (LV) using supplemental oxygen and hyperventilation and compressed-sensing acceleration. Breath-hold metrics [breath-hold duration, diaphragmatic/LV position drift, and maximum variation of R wave to R wave (RR) interval] without and with supplemental oxygen and hyperventilation were assessed in healthy adult subjects using a real-time single shot acquisition. Ten healthy subjects and 13 patients then underwent assessment of the proposed 3D breath-hold LGE acquisition (field of view = 320 × 320 × 100 mm(3) , resolution = 1.6 × 1.6 × 5.0 mm(3) , acceleration rate of 4) and a free-breathing acquisition with right hemidiaphragm navigator (NAV) respiratory gating. Semiquantitative grading of overall image quality, motion artifact, myocardial nulling, and diagnostic value was performed by consensus of two blinded observers. Supplemental oxygenation and hyperventilation increased the breath-hold duration (35 ± 11 s to 58 ± 21 s; P < 0.0125) without significant impact on diaphragmatic/LV position drift or maximum variation of RR interval (both P > 0.01). LGE images were of similar quality when compared with free-breathing acquisitions, but with reduced total scan time (85 ± 22 s to 35 ± 6 s; P < 0.001). Supplemental oxygenation and hyperventilation allow for prolonged breath-holding and enable single breath-hold 3D accelerated LGE with similar image quality as free breathing with NAV. Copyright © 2013 Wiley Periodicals, Inc.

Elastic flexure controls magma trajectories and explains the offset of primary volcanic activity upstream of mantle plume axis at la Réunion and Hawaii hotspot islands

NASA Astrophysics Data System (ADS)

Gerbault, Muriel; Fontaine, Fabrice J.; Rabinowicz, Michel; Bystricky, Misha

2017-03-01

Surface volcanism at la Réunion and Hawaii occurs with an offset of 150-180 km upstream to the plume axis with respect to the plate motion. This striking observation raises questions about the forcing of plume-lithosphere thermo-mechanical interactions on melt trajectories beneath these islands. Based on visco-elasto-plastic numerical models handled at kilometric resolution, we propose to explain this offset by the development of compressional stresses at the base of the lithosphere, that result from elastic plate bending above the upward load exerted by the plume head. This horizontal compression adopts a disc shape centered around the plume axis: (i) it is 20 km thick, (ii) it has a 150 km radius, (iii) it lays at the base of the elastic part of the lithosphere, i.e., around ∼50-70 km depth where the temperature varies from ∼600 °C to ∼750 °C, (iv) it lasts for 5 to 10 My in an oceanic plate of age greater than 70 My, and (vi) it is controlled by the visco-elastic relaxation time at ∼50-70 km depth. This period of time exceeds the time during which both the Somalian/East-African and Pacific plates drift over the Reunion and Hawaii plumes, respectively. This indicates that this basal compression is actually a persistent feature. It is inferred that the buoyant melts percolating in the plume head pond below this zone of compression and eventually spread laterally until the most compressive principal elastic stresses reverse to the vertical, i.e., ∼150 km away from the plume head. There, melts propagate through dikes upwards to ∼35 km depth, where the plate curvature reverses and ambient compression diminishes. This 30-35 km depth may thus host a magmatic reservoir where melts transported by dykes pond. Only after further magmatic differentiation can dykes resume their ascension up to the surface and begin forming a volcanic edifice. As the volcano grows because of melt accumulation at the top of the plate, the lithosphere is flexed downwards, inducing extra tensile stress at 30-35 km depth and compression at ∼15 km depth (induced by the edifice load). It implies that now the melts pond at ∼15 km and form another magmatic reservoir lying just underneath the crust. These processes explain the ponding of primary (shield) melts at ∼35 km and ∼15 km depths as recorded below La Reunion, Mauritius or Hawaii volcanoes, all shifted by ∼150 km with respect to the plume axis.

Winding Pack Height Management During Fabrication of the ITER CS Module

NASA Astrophysics Data System (ADS)

Martovetsky, Nicolai N.; Irick, David K.; Reed, Richard P.; Haefelfinger, Rolf; Salazar, Erica

The Central Solenoid (CS) stack consists of six modules, 2.1 m tall each [1]. In order to verify good impregnation, we performed a vacuum pressure impregnation (VPI) test of a full cross section of the CS module (CSM), 40 conductors tall and 14 conductors wide [2]. It was discovered that after preparation of the full cross section stack until completion of the VPI, the stack shrunk in height by 20-25 mm. Our study of the literature and discussions with the leading experts in VPI did not reveal obvious reasons for this change of height, so we launched a study to address this issue. We assembled two 12x1 (tall by wide) arrays and several 7x1 arrays in order to study characteristics of the dry winding pack under compressive force and effects of different fabrication steps. Then we impregnated these arrays in different conditions under compressive force and studied change of height as a result of compression, impregnation, gelling and curing of the stack of insulated conductors. We showed that by controlling the application of the compressive force, before closing the mold and during impregnation, one can reduce the height uncertainty. Most of the height reduction takes place while the glass is dry under the dead weight and the applied compressive force. Reduction of height during injection of the resin and during gelling, curing and cooling of the coil is noticeable, reproducible and relatively small. The paper presents results of our studies and recommendations for assembly and VPI of tall windings.

Redshift drift in an inhomogeneous universe: averaging and the backreaction conjecture

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

Koksbang, S.M.; Hannestad, S., E-mail: koksbang@phys.au.dk, E-mail: sth@phys.au.dk

2016-01-01

An expression for the average redshift drift in a statistically homogeneous and isotropic dust universe is given. The expression takes the same form as the expression for the redshift drift in FLRW models. It is used for a proof-of-principle study of the effects of backreaction on redshift drift measurements by combining the expression with two-region models. The study shows that backreaction can lead to positive redshift drift at low redshifts, exemplifying that a positive redshift drift at low redshifts does not require dark energy. Moreover, the study illustrates that models without a dark energy component can have an average redshiftmore » drift observationally indistinguishable from that of the standard model according to the currently expected precision of ELT measurements. In an appendix, spherically symmetric solutions to Einstein's equations with inhomogeneous dark energy and matter are used to study deviations from the average redshift drift and effects of local voids.« less

Compressive sensing sectional imaging for single-shot in-line self-interference incoherent holography

NASA Astrophysics Data System (ADS)

Weng, Jiawen; Clark, David C.; Kim, Myung K.

2016-05-01

A numerical reconstruction method based on compressive sensing (CS) for self-interference incoherent digital holography (SIDH) is proposed to achieve sectional imaging by single-shot in-line self-interference incoherent hologram. The sensing operator is built up based on the physical mechanism of SIDH according to CS theory, and a recovery algorithm is employed for image restoration. Numerical simulation and experimental studies employing LEDs as discrete point-sources and resolution targets as extended sources are performed to demonstrate the feasibility and validity of the method. The intensity distribution and the axial resolution along the propagation direction of SIDH by angular spectrum method (ASM) and by CS are discussed. The analysis result shows that compared to ASM the reconstruction by CS can improve the axial resolution of SIDH, and achieve sectional imaging. The proposed method may be useful to 3D analysis of dynamic systems.

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 7 2012-07-01 2012-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 7 2014-07-01 2014-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 7 2013-07-01 2013-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

46 CFR 153.236 - Prohibited materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Prohibited materials. 153.236 Section 153.236 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Containment Systems § 153.236 Prohibited materials. When one of the following paragraphs of this section is...

46 CFR 153.238 - Required materials.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Required materials. 153.238 Section 153.238 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Containment Systems § 153.238 Required materials. When one of the following paragraphs of this section is...

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

29 CFR 1917.155 - Air receivers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Air receivers. 1917.155 Section 1917.155 Labor Regulations...) MARINE TERMINALS Related Terminal Operations and Equipment § 1917.155 Air receivers. (a) Application. This section applies to compressed air receivers and equipment used for operations such as cleaning...

46 CFR 153.238 - Required materials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Required materials. 153.238 Section 153.238 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Containment Systems § 153.238 Required materials. When one of the following paragraphs of this section is...

46 CFR 153.236 - Prohibited materials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Prohibited materials. 153.236 Section 153.236 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Containment Systems § 153.236 Prohibited materials. When one of the following paragraphs of this section is...

46 CFR 153.238 - Required materials.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Required materials. 153.238 Section 153.238 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Containment Systems § 153.238 Required materials. When one of the following paragraphs of this section is...

46 CFR 153.236 - Prohibited materials.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Prohibited materials. 153.236 Section 153.236 Shipping... BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Containment Systems § 153.236 Prohibited materials. When one of the following paragraphs of this section is...

Reducing the impact of intensive care unit mattress compressibility during CPR: a simulation-based study.

PubMed

Lin, Yiqun; Wan, Brandi; Belanger, Claudia; Hecker, Kent; Gilfoyle, Elaine; Davidson, Jennifer; Cheng, Adam

2017-01-01

The depth of chest compression (CC) during cardiac arrest is associated with patient survival and good neurological outcomes. Previous studies showed that mattress compression can alter the amount of CCs given with adequate depth. We aim to quantify the amount of mattress compressibility on two types of ICU mattresses and explore the effect of memory foam mattress use and a backboard on mattress compression depth and effect of feedback source on effective compression depth. The study utilizes a cross-sectional self-control study design. Participants working in the pediatric intensive care unit (PICU) performed 1 min of CC on a manikin in each of the following four conditions: (i) typical ICU mattress; (ii) typical ICU mattress with a CPR backboard; (iii) memory foam ICU mattress; and (iv) memory foam ICU mattress with a CPR backboard, using two different sources of real-time feedback: (a) external accelerometer sensor device measuring total compression depth and (b) internal light sensor measuring effective compression depth only. CPR quality was concurrently measured by these two devices. The differences of the two measures (mattress compression depth) were summarized and compared using multilevel linear regression models. Effective compression depths with different sources of feedback were compared with a multilevel linear regression model. The mean mattress compression depth varied from 24.6 to 47.7 mm, with percentage of depletion from 31.2 to 47.5%. Both use of memory foam mattress (mean difference, MD 11.7 mm, 95%CI 4.8-18.5 mm) and use of backboard (MD 11.6 mm, 95% CI 9.0-14.3 mm) significantly minimized the mattress compressibility. Use of internal light sensor as source of feedback improved effective CC depth by 7-14 mm, compared with external accelerometer sensor. Use of a memory foam mattress and CPR backboard minimizes mattress compressibility, but depletion of compression depth is still substantial. A feedback device measuring sternum-to-spine displacement can significantly improve effective compression depth on a mattress. Not applicable. This is a mannequin-based simulation research.

Evaluation of modeling for groundwater flow and tetrachloroethylene transport in the Milford-Souhegan glacial-drift aquifer at the Savage Municipal Well Superfund site, Milford, New Hampshire, 2011

USGS Publications Warehouse

Harte, Philip T.

2012-01-01

The U.S. Geological Survey and the New Hampshire Department of Environmental Services entered into a cooperative agreement to assist in the evaluation of remedy simulations of the MSGD aquifer that are being performed by various parties to track the remedial progress of the PCE plume. This report summarizes findings from this evaluation. Topics covered include description of groundwater flow and transport models used in the study of the Savage Superfund site (section 2), evaluation of models and their results (section 3), testing of several new simulations (section 4), an assessment of the representation of models to simulate field conditions (section 5), and an assessment of models as a tool in remedial operational decision making (section 6).

Relationships of forest vegetation to habitat on two types of glacial drift in New Hampshire

Treesearch

William B. Leak

1978-01-01

Species composition and site index were determined on nine tree habitats in an area of schistose drift and compared with previous findings on habitats with granitic drift. Habitats on schistose drift supported more sugar maple and had somewhat higher site indexes. Compact tills in schistose drift supported northern hardwoods, and the site indexes for yellow birch were...

Electrophysiological examination and high frequency ultrasonography for diagnosis of radial nerve torsion and compression

PubMed Central

Shi, Miao; Qi, Hengtao; Ding, Hongyu; Chen, Feng; Xin, Zhaoqin; Zhao, Qinghua; Guan, Shibing; Shi, Hao

2018-01-01

Abstract This study aims to evaluate the value of electrophysiological examination and high frequency ultrasonography in the differential diagnosis of radial nerve torsion and radial nerve compression. Patients with radial nerve torsion (n = 14) and radial nerve compression (n = 14) were enrolled. The results of neurophysiological and high frequency ultrasonography were compared. Electrophysiological examination and high-frequency ultrasonography had a high diagnostic rate for both diseases with consistent results. Of the 28 patients, 23 were positive for electrophysiological examination, showing decreased amplitude and decreased conduction velocity of radial nerve; however, electrophysiological examination cannot distinguish torsion from compression. A total of 27 cases showed positive in ultrasound examinations among all 28 cases. On ultrasound images, the nerve was thinned at torsion site whereas thickened at the distal ends of torsion. The diameter and cross-sectional area of torsion or compression determined the nerve damage, and ultrasound could locate the nerve injury site and measure the length of the nerve. Electrophysiological examination and high-frequency ultrasonography can diagnose radial neuropathy, with electrophysiological examination reflecting the neurological function, and high-frequency ultrasound differentiating nerve torsion from compression. PMID:29480857

A Molecular Clock Infers Heterogeneous Tissue Age Among Patients with Barrett’s Esophagus

PubMed Central

Wong, Chao-Jen; Hazelton, William D.; Kaz, Andrew M.; Willis, Joseph E.; Grady, William M.; Luebeck, E. Georg

2016-01-01

Biomarkers that drift differentially with age between normal and premalignant tissues, such as Barrett’s esophagus (BE), have the potential to improve the assessment of a patient’s cancer risk by providing quantitative information about how long a patient has lived with the precursor (i.e., dwell time). In the case of BE, which is a metaplastic precursor to esophageal adenocarcinoma (EAC), such biomarkers would be particularly useful because EAC risk may change with BE dwell time and it is generally not known how long a patient has lived with BE when a patient is first diagnosed with this condition. In this study we first describe a statistical analysis of DNA methylation data (both cross-sectional and longitudinal) derived from tissue samples from 50 BE patients to identify and validate a set of 67 CpG dinucleotides in 51 CpG islands that undergo age-related methylomic drift. Next, we describe how this information can be used to estimate a patient’s BE dwell time. We introduce a Bayesian model that incorporates longitudinal methylomic drift rates, patient age, and methylation data from individually paired BE and normal squamous tissue samples to estimate patient-specific BE onset times. Our application of the model to 30 sporadic BE patients’ methylomic profiles first exposes a wide heterogeneity in patient-specific BE onset times. Furthermore, independent application of this method to a cohort of 22 familial BE (FBE) patients reveals significantly earlier mean BE onset times. Our analysis supports the conjecture that differential methylomic drift occurs in BE (relative to normal squamous tissue) and hence allows quantitative estimation of the time that a BE patient has lived with BE. PMID:27168458

Erratum: ``Evidence that a Deep Meridional Flow Sets the Sunspot Cycle Period'' (ApJ, 589, 665 [2003])

NASA Astrophysics Data System (ADS)

Hathaway, David H.; Nandy, Dibyendu; Wilson, Robert M.; Reichmann, Edwin J.

2004-02-01

An error was made in entering the data used in Figure 6. This changes the results concerning the length of the time lag between the variations in the meridional flow speed and those in the cycle amplitude. The final paragraph on page 667 should read: ``Finally, we study the relationship between the drift velocities and the amplitudes of the hemisphere/cycles. In Figure 5 we compare the drift velocity at the maximum of the cycle to the amplitude of that cycle for that hemisphere. There is a positive (0.5) and significant (95%) correlation between the two. However, an even stronger relationship is found between the drift velocity and the amplitude of the N+2 cycle. The correlation is stronger (0.7) and more significant (99%), as shown in Figure 6. This relationship is suggestive of a ``memory'' in the solar cycle, again a property of dynamo models that use meridional circulation. Indeed, the two-cycle lag is precisely the relationship found by Charbonneau & Dikpati (ApJ, 589, 665 [2003]). This behavior is, however, more difficult to interpret, and we elaborate on this in the next section. In either case, these correlations only explain part of the variance in cycle amplitude (25% for the current cycle and 50% for the N+2 cycle). Obviously, other mechanisms, such as variations in the gradient in the rotation rate, also contribute to the cycle amplitude variations. Our investigation of possible connections between drift rates and the amplitudes of the N+1 and N+3 cycles gives no significant correlations at these alternative time lags.'' The revised Figure 6 and its caption are given below

Brownian motion with adaptive drift for remaining useful life prediction: Revisited

NASA Astrophysics Data System (ADS)

Wang, Dong; Tsui, Kwok-Leung

2018-01-01

Linear Brownian motion with constant drift is widely used in remaining useful life predictions because its first hitting time follows the inverse Gaussian distribution. State space modelling of linear Brownian motion was proposed to make the drift coefficient adaptive and incorporate on-line measurements into the first hitting time distribution. Here, the drift coefficient followed the Gaussian distribution, and it was iteratively estimated by using Kalman filtering once a new measurement was available. Then, to model nonlinear degradation, linear Brownian motion with adaptive drift was extended to nonlinear Brownian motion with adaptive drift. However, in previous studies, an underlying assumption used in the state space modelling was that in the update phase of Kalman filtering, the predicted drift coefficient at the current time exactly equalled the posterior drift coefficient estimated at the previous time, which caused a contradiction with the predicted drift coefficient evolution driven by an additive Gaussian process noise. In this paper, to alleviate such an underlying assumption, a new state space model is constructed. As a result, in the update phase of Kalman filtering, the predicted drift coefficient at the current time evolves from the posterior drift coefficient at the previous time. Moreover, the optimal Kalman filtering gain for iteratively estimating the posterior drift coefficient at any time is mathematically derived. A discussion that theoretically explains the main reasons why the constructed state space model can result in high remaining useful life prediction accuracies is provided. Finally, the proposed state space model and its associated Kalman filtering gain are applied to battery prognostics.

The initial value problem in Lagrangian drift kinetic theory

NASA Astrophysics Data System (ADS)

Burby, J. W.

2016-06-01

> Existing high-order variational drift kinetic theories contain unphysical rapidly varying modes that are not seen at low orders. These unphysical modes, which may be rapidly oscillating, damped or growing, are ushered in by a failure of conventional high-order drift kinetic theory to preserve the structure of its parent model's initial value problem. In short, the (infinite dimensional) system phase space is unphysically enlarged in conventional high-order variational drift kinetic theory. I present an alternative, `renormalized' variational approach to drift kinetic theory that manifestly respects the parent model's initial value problem. The basic philosophy underlying this alternate approach is that high-order drift kinetic theory ought to be derived by truncating the all-orders system phase-space Lagrangian instead of the usual `field particle' Lagrangian. For the sake of clarity, this story is told first through the lens of a finite-dimensional toy model of high-order variational drift kinetics; the analogous full-on drift kinetic story is discussed subsequently. The renormalized drift kinetic system, while variational and just as formally accurate as conventional formulations, does not support the troublesome rapidly varying modes.

Exploring the interior of cuticles and compressions of fossil plants by FIB-SEM milling and image microscopy.

PubMed

Sender, L M; Escapa, I; Benedetti, A; Cúneo, R; Diez, J B

2018-01-01

We present the first study of cuticles and compressions of fossil leaves by Focused Ion Beam Scanning Electron Microscopy (FIB-SEM). Cavities preserved inside fossil leaf compressions corresponding to substomatal chambers have been observed for the first time and several new features were identified in the cross-section cuts. These results open a new way in the investigation of the three-dimensional structures of both micro- and nanostructural features of fossil plants. Moreover, the application of the FIB-SEM technique to both fossils and extant plant remains represent a new source of taxonomical, palaeoenvironmental and palaeoclimatic information. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

An aggressive vertebral hemangioma in pregnancy: a case report.

PubMed

Slimani, Ouafae; Jayi, Sofia; Fdili Alaoui, Fatimazahra; Bouguern, Hakima; Chaara, Hekmat; Fikri, Ghizlane; Alaoui Rachidi, Siham; Sqalli Houssaini, Nadia; Himmich, Mariam; Abdelilah Melhouf, Moulay

2014-06-18

Pregnancy-related compressive myelopathy secondary to vertebral hemangioma is a rare occurrence and its treatment antepartum is rare. A 19-year-old North African woman in her 38th week of pregnancy presented with paraplegia that progressed within 2 days after a rapidly progressive weakness of her lower limbs. Magnetic resonance imaging studies showed compression of her spinal cord in front of the fourth thoracic vertebra for suspected tuberculous spondylitis. A Caesarean section was done followed by corpectomy with a bone graft because we intraoperatively discovered a vertebral hemangioma. Pathology showed an aggressive hemangioma. At any term of pregnancy, extensive neurological involvement which is rapidly progressive due to compression should be considered for immediate decompression.

Mechanisms of compressive failure in woven composites and stitched laminates

NASA Technical Reports Server (NTRS)

Cox, B. N.; Dadkhah, M. S.; Inman, R. V.; Morris, W. L.; Schroeder, S.

1992-01-01

Stitched laminates and angle interlock woven composites have been studied in uniaxial, in-plane, monotonic compression. Failure mechanisms have been found to depend strongly on both the reinforcement architecture and the degree of constraint imposed by the loading grips. Stitched laminates show higher compressive strength, but are brittle, possessing no load bearing capacity beyond the strain for peak load. Post-mortem inspection shows a localized shear band of buckled and broken fibers, which is evidently the product of an unstably propagating kink band. Similar shear bands are found in the woven composites if the constraint of lateral displacements is weak; but, under strong constraint, damage is not localized but distributed throughout the gauge section. While the woven composites tested are weaker than the stitched laminates, they continue to bear significant loads to compressive strains of approx. 15 percent, even when most damage is confined to a shear band.

Vascular compression as a potential cause of occipital neuralgia: a case report.

PubMed

White, J B; Atkinson, P P; Cloft, H J; Atkinson, J L D

2008-01-01

Vascular compression is a well-established cause of cranial nerve neuralgic syndromes. A unique case is presented that demonstrates that vascular compression may be a possible cause of occipital neuralgia. A 48-year-old woman with refractory left occipital neuralgia revealed on magnetic resonance imaging and computed tomographic imaging of the upper cervical spine an atypically low loop of the left posterior inferior cerebellar artery (PICA), clearly indenting the dorsal upper cervical roots. During surgery, the PICA loop was interdigitated with the C1 and C2 dorsal roots. Microvascular decompression alone has never been described for occipital neuralgia, despite the strong clinical correlation in this case. Therefore, both sectioning the dorsal roots of C2 and microvascular decompression of the PICA loop were performed. Postoperatively, the patient experienced complete cure of her neuralgia. Vascular compression as a cause of refractory occipital neuralgia should be considered when assessing surgical options.

Valorisation of blueberry waste and use of compression to manufacture sustainable starch films with enhanced properties.

PubMed

Luchese, Cláudia Leites; Uranga, Jone; Spada, Jordana Corralo; Tessaro, Isabel Cristina; de la Caba, Koro

2018-08-01

Blueberry waste from juice processing was valorised to develop starch films by compression moulding. The compression process resulted in hydrophobic films with water contact angles even higher than 100° for the films prepared with the highest blueberry waste content. Additionally, the film solubility was reduced by the incorporation of blueberry waste, regardless of the solution pH. These films also exhibited good barrier properties against UV light due to the aromatic compounds present in the blueberry waste. Furthermore, films showed a homogenous surface, although some pores appeared in the cross-section for the films with the highest blueberry waste content. Results highlighted the use of thermo-mechanical processes such as compression to manufacture sustainable films with enhanced properties through waste valorisation by the techniques actually employed at industrial scale. Copyright © 2018 Elsevier B.V. All rights reserved.

LINEAR ACCELERATOR

DOEpatents

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

1959-02-17

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

The drift velocity monitoring system of the CMS barrel muon chambers

NASA Astrophysics Data System (ADS)

Altenhöfer, Georg; Hebbeker, Thomas; Heidemann, Carsten; Reithler, Hans; Sonnenschein, Lars; Teyssier, Daniel

2018-04-01

The drift velocity is a key parameter of drift chambers. Its value depends on several parameters: electric field, pressure, temperature, gas mixture, and contamination, for example, by ambient air. A dedicated Velocity Drift Chamber (VDC) with 1-L volume has been built at the III. Phys. Institute A, RWTH Aachen, in order to monitor the drift velocity of all CMS barrel muon Drift Tube chambers. A system of six VDCs was installed at CMS and has been running since January 2011. We present the VDC monitoring system, its principle of operation, and measurements performed.

Using different drift gases to change separation factors (alpha) in ion mobility spectrometry

PubMed

Asbury; Hill

2000-02-01

The use of different drift gases to alter separation factors (alpha) in ion mobility spectrometry has been demonstrated. The mobility of a series of low molecular weight compounds and three small peptides was determined in four different drift gases. The drift gases chosen were helium, argon, nitrogen, and carbon dioxide. These drift gases provide a range of polarizabilities and molecular weights. In all instances, the compounds showed the greatest mobility in helium and the lowest mobility in carbon dioxide; however the percentage change of mobility for each compound was different, effectively changing the alpha value. The alpha value changes were primarily due to differences in drift gas polarizability but were also influenced by the mass of the drift gas. In addition, gas-phase ion radii were calculated in each of the different drift gases. These radii were then plotted against drift gas polarizability producing linear plots with r2 values greater than 0.99. The intercept of these plots provides the gas-phase radius of an ion in a nonpolarizing environment, whereas the slope is indicative of the magnitude of the ion's mobility change related to polarizability. It therefore, should be possible to separate any two compounds that have different slopes with the appropriate drift gas.

Laboratory Simulation and Measurement of Instrument Drift in Quartz-Resonant Pressure Gauges

NASA Astrophysics Data System (ADS)

Sasagawa, G. S.; Zumberge, M. A.

2017-12-01

Marine geodesy uses ocean bottom pressure sensors to measure vertical deformation of the sea floor, including that due to volcanic inflation and subsidence, episodic tremor and slip, plate subduction, and deformation due to hydrocarbon extraction at offshore reservoirs. Instrumental drift is inherent in existing pressure sensors and introduce uncertainties in data interpretation. Different methods have been developed to control drift, using varying techniques and instrumentation. Laboratory measurements of sensor drift, under controlled conditions that simulate seafloor pressures and temperatures, would allow for evaluating pressure gauge drift and the efficacy of new drift control methods. We have constructed and operated a laboratory system to monitor the drift of 15 quartz resonant pressure gauges over a year. The temperature and pressure are maintained and controlled at approximately 5 °C and 1900 dbar. A deadweight tester was used to provide a reference signal at frequent intervals; the time series of reference pressure signals is a direct measure of each gauge's drift. Several other tests were conducted, including a) evaluation of a custom outgassing sensor used as proxy for instrument drift, b) determination of the oscillator drift in the pressure gauge signal conditioning electronics, and c) a test of ambient air pressure calibration, also known as the A-0-A method. First results will be presented.

Determining the drift potential of Venturi nozzles compared with standard nozzles across three insecticide spray solutions in a wind tunnel.

PubMed

Ferguson, J Connor; Chechetto, Rodolfo G; O'Donnell, Chris C; Dorr, Gary J; Moore, John H; Baker, Greg J; Powis, Kevin J; Hewitt, Andrew J

2016-08-01

Previous research has sought to adopt the use of drift-reducing technologies (DRTs) for use in field trials to control diamondback moth (DBM) Plutella xylostella (L.) (Lepidoptera: Plutellidae) in canola (Brassica napus L.). Previous studies observed no difference in canopy penetration from fine to coarse sprays, but the coverage was higher for fine sprays. DBM has a strong propensity to avoid sprayed plant material, putting further pressure on selecting technologies that maximise coverage, but often this is at the expense of a greater drift potential. This study aims to examine the addition of a DRT oil that is labelled for control of DBM as well and its effect on the drift potential of the spray solution. The objectives of the study are to quantify the droplet size spectrum and spray drift potential of each nozzle type to select technologies that reduce spray drift, to examine the effect of the insecticide tank mix at both (50 and 100 L ha(-1) ) application rates on droplet size and spray drift potential across tested nozzle type and to compare the droplet size results of each nozzle by tank mix against the drift potential of each nozzle. The nozzle type affected the drift potential the most, but the spray solution also affected drift potential. The fine spray quality (TCP) resulted in the greatest drift potential (7.2%), whereas the coarse spray quality (AIXR) resulted in the lowest (1.3%), across all spray solutions. The spray solutions mixed at the 100 L ha(-1) application volume rate resulted in a higher drift potential than the same products mixed at the 50 L ha(-1) mix rate. The addition of the paraffinic DRT oil was significant in reducing the drift potential of Bacillus thuringiensis var. kurstkai (Bt)-only treatments across all tested nozzle types. The reduction in drift potential from the fine spray quality to the coarse spray quality was up to 85%. The addition of a DRT oil is an effective way to reduce the spray solution drift potential across all nozzle types and tank mixes evaluated in this study. The greatest reduction in drift potential can be achieved by changing nozzle type, which can reduce the losses of the spray to the surrounding environment. Venturi nozzles greatly reduce the drift potential compared with standard nozzles by as much as 85% across all three insecticide spray solutions. Results suggest that a significant reduction in drift potential can be achieved by changing the nozzle type, and can be achieved without a loss in control of DBM. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

29 CFR 1926.306 - Air receivers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 8 2014-07-01 2014-07-01 false Air receivers. 1926.306 Section 1926.306 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Tools-Hand and Power § 1926.306 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other equipment used in...

29 CFR 1926.306 - Air receivers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 8 2012-07-01 2012-07-01 false Air receivers. 1926.306 Section 1926.306 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Tools-Hand and Power § 1926.306 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other equipment used in...

29 CFR 1926.306 - Air receivers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 8 2013-07-01 2013-07-01 false Air receivers. 1926.306 Section 1926.306 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Tools-Hand and Power § 1926.306 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other equipment used in...

29 CFR 1926.306 - Air receivers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 8 2010-07-01 2010-07-01 false Air receivers. 1926.306 Section 1926.306 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Tools-Hand and Power § 1926.306 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other equipment used in...

29 CFR 1926.306 - Air receivers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 8 2011-07-01 2011-07-01 false Air receivers. 1926.306 Section 1926.306 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Tools-Hand and Power § 1926.306 Air receivers. (a) General requirements—(1) Application. This section applies to compressed air receivers, and other equipment used in...

40 CFR 94.6 - Regulatory structure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Regulatory structure. 94.6 Section 94... for Compression-Ignition Marine Engines § 94.6 Regulatory structure. This section provides an overview of the regulatory structure of this part. (a) The regulations of this Part 94 are intended to control...

40 CFR 94.105 - Duty cycles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Duty cycles. 94.105 Section 94.105... EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES Test Procedures § 94.105 Duty cycles. (a) Overview. For....8(e), engines shall be tested using the appropriate duty cycles described in this section. (b...

OpenDrift v1.0: a generic framework for trajectory modelling

NASA Astrophysics Data System (ADS)

Dagestad, Knut-Frode; Röhrs, Johannes; Breivik, Øyvind; Ådlandsvik, Bjørn

2018-04-01

OpenDrift is an open-source Python-based framework for Lagrangian particle modelling under development at the Norwegian Meteorological Institute with contributions from the wider scientific community. The framework is highly generic and modular, and is designed to be used for any type of drift calculations in the ocean or atmosphere. A specific module within the OpenDrift framework corresponds to a Lagrangian particle model in the traditional sense. A number of modules have already been developed, including an oil drift module, a stochastic search-and-rescue module, a pelagic egg module, and a basic module for atmospheric drift. The framework allows for the ingestion of an unspecified number of forcing fields (scalar and vectorial) from various sources, including Eulerian ocean, atmosphere and wave models, but also measurements or a priori values for the same variables. A basic backtracking mechanism is inherent, using sign reversal of the total displacement vector and negative time stepping. OpenDrift is fast and simple to set up and use on Linux, Mac and Windows environments, and can be used with minimal or no Python experience. It is designed for flexibility, and researchers may easily adapt or write modules for their specific purpose. OpenDrift is also designed for performance, and simulations with millions of particles may be performed on a laptop. Further, OpenDrift is designed for robustness and is in daily operational use for emergency preparedness modelling (oil drift, search and rescue, and drifting ships) at the Norwegian Meteorological Institute.

Development of lightweight aluminum compression panels reinforced by boron-epoxy infiltrated extrusions

NASA Technical Reports Server (NTRS)

Roy, P. A.; Mcelman, J. A.; Henshaw, J.

1973-01-01

Analytical and experimental studies were performed to evaluate the structural efficiencies afforded by the selective reinforcement of conventional aluminum compression panels with unidirectional boron epoxy composite materials. A unique approach for selective reinforcement was utilized called boron/epoxy infiltration. This technique uses extruded metal sections with preformed hollow voids into which unidirectional boron filaments are drawn and subsequently infiltrated with resin to form an integral part. Simplified analytical models were developed to investigate the behavior of stiffener webs with reinforced flanges. Theoretical results are presented demonstrating the effects of transverse shear, of the reinforcement, flange eccentricity and torsional stiffness in such construction. A series of 55 tests were conducted on boron-infiltrated rods and extruded structural sections.

Time dependent variation of carrying capacity of prestressed precast beam

NASA Astrophysics Data System (ADS)

Le, Tuan D.; Konečný, Petr; Matečková, Pavlína

2018-04-01

The article deals with the evaluation of the precast concrete element time dependent carrying capacity. The variation of the resistance is inherited property of laboratory as well as in-situ members. Thus the specification of highest, yet possible, laboratory sample resistance is important with respect to evaluation of laboratory experiments based on the test machine loading capabilities. The ultimate capacity is evaluated through the bending moment resistance of a simply supported prestressed concrete beam. The probabilistic assessment is applied. Scatter of random variables of compressive strength of concrete and effective height of the cross section is considered. Monte Carlo simulation technique is used to investigate the performance of the cross section of the beam with changes of tendons’ positions and compressive strength of concrete.

Charts for the minimum-weight design of 24s-t aluminum-alloy flat compression panels with longitudinal z-section stiffeners

NASA Technical Reports Server (NTRS)

Schuette, Evan H

1945-01-01

Design charts are developed for 24s-t aluminum-alloy flat compression panels with longitudinal z-section stiffeners. These charts make possible the design of the lightest panels of this type for a wide range of design requirements. Examples of the use of the charts are given and it is pointed out on the basis of these examples that, over a wide range of design conditions, the maintenance of buckle-free surfaces does not conflict with the achievement of high structural efficiency. The achievement of the maximum possible structural efficiency with 24s-t aluminum-alloy panels, however, requires closer stiffener spacings than those now in common use.

Seal assembly

DOEpatents

Johnson, Roger Neal; Longfritz, William David

2001-01-01

A seal assembly that seals a gap formed by a groove comprises a seal body, a biasing element, and a connection that connects the seal body to the biasing element to form the seal assembly. The seal assembly further comprises a concave-shaped center section and convex-shaped contact portions at each end of the seal body. The biasing element is formed from an elastic material and comprises a convex-shaped center section and concave-shaped biasing zones that are opposed to the convex-shaped contact portions. The biasing element is adapted to be compressed to change a width of the seal assembly from a first width to a second width that is smaller than the first width. In the compressed state, the seal assembly can be disposed in the groove. After release of the compressing force, the seal assembly expands. The contact portions will move toward a surface of the groove and the biasing zones will move into contact with another surface of the groove. The biasing zones will bias the contact portions of the seal body against the surface of the groove.

Cryo-transmission electron microscopy of frozen-hydrated sections of Escherichia coli and Pseudomonas aeruginosa.

PubMed

Matias, Valério R F; Al-Amoudi, Ashraf; Dubochet, Jacques; Beveridge, Terry J

2003-10-01

High-pressure freezing of Escherichia coli K-12 and Pseudomonas aeruginosa PAO1 in the presence of cryoprotectants provided consistent vitrification of cells so that frozen-hydrated sections could be cut, providing approximately 2-nm resolution of structure. The size and shape of the bacteria, as well as their surface and cytoplasmic constituents, were nicely preserved and compared well with other published high-resolution techniques. Cells possessed a rich cytoplasm containing a diffuse dispersion of ribosomes and genetic material. Close examination of cells revealed that the periplasmic space was compressed during cryosectioning, a finding which provided supporting evidence that this space is filled by a compressible gel. Since the outer membrane and peptidoglycan layer are bonded together via lipoproteins, the space between them (although still part of the periplasmic space) was not as compacted. Even when this cryosectioning compression was taken into account, there was still substantial variability in the width of the periplasmic space. It is possible that the protoplast has some capacity to float freely within the periplasm.

Pulsed discharge ionization source for miniature ion mobility spectrometers

DOEpatents

Xu, Jun; Ramsey, J. Michael; Whitten, William B.

2004-11-23

A method and apparatus is disclosed for flowing a sample gas and a reactant gas (38, 43) past a corona discharge electrode (26) situated at a first location in an ion drift chamber (24), applying a pulsed voltage waveform comprising a varying pulse component and a dc bias component to the corona discharge electrode (26) to cause a corona which in turn produces ions from the sample gas and the reactant gas, applying a dc bias to the ion drift chamber (24) to cause the ions to drift to a second location (25) in the ion drift chamber (24), detecting the ions at the second location (25) in the drift chamber (24), and timing the period for the ions to drift from the corona discharge electrode to the selected location in the drift chamber.

The generalized drift flux approach: Identification of the void-drift closure law

NASA Technical Reports Server (NTRS)

Boure, J. A.

1989-01-01

The main characteristics and the potential advantages of generalized drift flux models are presented. In particular it is stressed that the issue on the propagation properties and on the mathematical nature (hyperbolic or not) of the model and the problem of closure are easier to tackle than in two fluid models. The problem of identifying the differential void-drift closure law inherent to generalized drift flux models is then addressed. Such a void-drift closure, based on wave properties, is proposed for bubbly flows. It involves a drift relaxation time which is of the order of 0.25 s. It is observed that, although wave properties provide essential closure validity tests, they do not represent an easily usable source of quantitative information on the closure laws.

The preparation of Drosophila embryos for live-imaging using the hanging drop protocol.

PubMed

Reed, Bruce H; McMillan, Stephanie C; Chaudhary, Roopali

2009-03-13

Green fluorescent protein (GFP)-based timelapse live-imaging is a powerful technique for studying the genetic regulation of dynamic processes such as tissue morphogenesis, cell-cell adhesion, or cell death. Drosophila embryos expressing GFP are readily imaged using either stereoscopic or confocal microscopy. A goal of any live-imaging protocol is to minimize detrimental effects such as dehydration and hypoxia. Previous protocols for preparing Drosophila embryos for live-imaging analysis have involved placing dechorionated embryos in halocarbon oil and sandwiching them between a halocarbon gas-permeable membrane and a coverslip. The introduction of compression through mounting embryos in this manner represents an undesirable complication for any biomechanical-based analysis of morphogenesis. Our method, which we call the hanging drop protocol, results in excellent viability of embryos during live imaging and does not require that embryos be compressed. Briefly, the hanging drop protocol involves the placement of embryos in a drop of halocarbon oil that is suspended from a coverslip, which is, in turn, fixed in position over a humid chamber. In addition to providing gas exchange and preventing dehydration, this arrangement takes advantage of the buoyancy of embryos in halocarbon oil to prevent them from drifting out of position during timelapse acquisition. This video describes in detail how to collect and prepare Drosophila embryos for live imaging using the hanging drop protocol. This protocol is suitable for imaging dechorionated embryos using stereomicroscopy or any upright compound fluorescence microscope.

Changes in apparent duration follow shifts in perceptual timing

PubMed Central

Bruno, Aurelio; Ayhan, Inci; Johnston, Alan

2015-01-01

It is well established that the apparent duration of moving visual objects is greater at higher as compared to slower speeds. Here we report the effects of acceleration and deceleration on the perceived duration of a drifting grating with average speed kept constant (10°/s).For acceleration, increasing the speed range progressively reduced perceived duration. The magnitude of apparent duration compression was determined by speed rather than temporal frequency and was proportional to speed range (independent of standard duration) rather than acceleration. The perceived duration reduction was also proportional to the standard length. The effects of increases and decreases in speed were highly asymmetric. Reducing speed through the interval induced a moderate increase in perceived duration. These results could not be explained by changes in apparent onset or offset or differences in perceived average speed between intervals containing increasing speed and intervals containing decreasing speed. Paradoxically, for intervals combining increasing speed and decreasing speed, compression only occurred when increasing speed occurred in the second half of the interval. We show that this pattern of results in the duration domain was concomitant with changes in the reported direction of apparent motion of Gaussian blobs, embedded in intervals of increasing or decreasing speed, that could be predicted from adaptive changes in the temporal impulse response function. We detected similar changes after flicker adaptation, suggesting that the two effects might be linked through changes in the temporal tuning of visual filters. PMID:26024450

Dislocation Multiplication in the Early Stage of Deformation in Mo Single Crystals

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

Hsiung, L.; Lassila, D.H.

Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied using transmission electron microscopy (TEM) techniques in order to investigate dislocation multiplication mechanisms in the early stage of plastic deformation. The initial dislocation density is in a range of 10{sup 6} {approx} 10{sup 7} cm{sup -2}, and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 10{sup 8} {approx} 10{sup 9} cm{sup -2}, and the average jog height is also found to increase aftermore » compressing for a total strain of 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. The jog height can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. The coalescence of superjogs results in an increase of both link length and jog height. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This ''dynamic'' dislocation multiplication source is suggested to be crucial for the dislocation multiplication in the early stage of plastic deformation in Mo.« less

Community Air Monitoring for Pesticide Drift Using Pesticide Action Network's (PAN) Drift Catcher

NASA Astrophysics Data System (ADS)

Marquez, E.

2016-12-01

Community air monitoring projects for pesticides in the air have been conducted by PAN in collaboration with community members and locally based groups engaged around pesticide issues. PAN is part of an international network working to promote a just, thriving food system and replace the use of hazardous pesticides with ecologically sound alternatives. The Drift Catcher is an air-monitoring device with a design based on the California Air Resource Board's air monitoring equipment, and has been used in community-based projects in 11 states. Observations of pesticide drift made by community members cannot always be confirmed by regulatory agencies—if an inspection is made hours or days after a drift incident, the evidence may no longer be present. The Drift Catcher makes it possible to collect scientific evidence of pesticide drift in areas where people live, work, and play. One of the most recent Drift Catcher projects was done in California, in partnership with the Safe Strawberry Coalition and led by the statewide coalition Californians for Pesticide Reform. The data were used to support a call for stronger mitigation rules for the fumigant chloropicrin and to support a campaign asking for stronger pesticide rules to protect children attending school in close proximity to agricultural fields. The Drift Catcher data are used by organizers and community members to engage policymakers with the intention of making policy change on a local and/or statewide level. On the national level, PAN's Drift Catcher data has helped win regulatory recognition of volatilization drift for pesticides other than fumigants. Lessons learned from conducting community-based research projects will also be discussed. PAN is also currently assessing other community-based monitoring tools, such as community surveys and drift questionnaires that may allow communities to collect data that can also support the campaign work.

High-Performance Ion Mobility Spectrometry Using Hourglass Electrodynamic Funnel And Internal Ion Funnel

DOEpatents

Smith, Richard D.; Tang, Keqi; Shvartsburg, Alexandre A.

2004-11-16

A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.

Different types of drifts in two seasonal forecast systems and their dependence on ENSO

NASA Astrophysics Data System (ADS)

Hermanson, L.; Ren, H.-L.; Vellinga, M.; Dunstone, N. D.; Hyder, P.; Ineson, S.; Scaife, A. A.; Smith, D. M.; Thompson, V.; Tian, B.; Williams, K. D.

2017-11-01

Seasonal forecasts using coupled ocean-atmosphere climate models are increasingly employed to provide regional climate predictions. For the quality of forecasts to improve, regional biases in climate models must be diagnosed and reduced. The evolution of biases as initialized forecasts drift away from the observations is poorly understood, making it difficult to diagnose the causes of climate model biases. This study uses two seasonal forecast systems to examine drifts in sea surface temperature (SST) and precipitation, and compares them to the long-term bias in the free-running version of each model. Drifts are considered from daily to multi-annual time scales. We define three types of drift according to their relation with the long-term bias in the free-running model: asymptoting, overshooting and inverse drift. We find that precipitation almost always has an asymptoting drift. SST drifts on the other hand, vary between forecasting systems, where one often overshoots and the other often has an inverse drift. We find that some drifts evolve too slowly to have an impact on seasonal forecasts, even though they are important for climate projections. The bias found over the first few days can be very different from that in the free-running model, so although daily weather predictions can sometimes provide useful information on the causes of climate biases, this is not always the case. We also find that the magnitude of equatorial SST drifts, both in the Pacific and other ocean basins, depends on the El Niño Southern Oscillation (ENSO) phase. Averaging over all hindcast years can therefore hide the details of ENSO state dependent drifts and obscure the underlying physical causes. Our results highlight the need to consider biases across a range of timescales in order to understand their causes and develop improved climate models.

Spray particle drift mitigation using field corn (Zea mays L.) as a drift barrier.

PubMed

Vieira, Bruno C; Butts, Thomas R; Rodrigues, Andre O; Golus, Jeffrey A; Schroeder, Kasey; Kruger, Greg R

2018-04-24

Herbicide particle drift reduces application efficacy and can cause severe impacts on nearby vegetation depending on the herbicide mode-of-action, exposure level, and tolerance to the herbicide. A particle drift mitigation effort placing windbreaks or barriers on the field boundaries to reduce off-target movement of spray particles has been utilized in the past. The objective of this research was to evaluate the effectiveness of field corn (Zea mays L.) at different heights as a particle drift barrier. Applications with a non-air inclusion flat fan nozzle (ER11004) resulted in greater particle drift when compared to an air inclusion nozzle (TTI11004). Eight rows of corn were used as barriers (0.91, 1.22, and 1.98 m height) which reduced the particle drift for both nozzles, especially at shorter downwind distances. Applications with the ER11004 nozzle without corn barriers had 1% of the applied rate (D 99 ) predicted to deposit at 14.8 m downwind, whereas this distance was reduced (up to 7-fold) when applications were performed with corn barriers. The combination of corn drift barriers and nozzle selection (TTI11004) provided satisfactory particle drift reduction when the D 99 estimates were compared to applications with the ER11004 nozzle without corn barriers (up to 10-fold difference). The corn drift barriers were effective in reducing particle drift from applications with the ER11004 and the TTI11004 nozzles (Fine and Ultra Coarse spray classifications, respectively). The corn drift barrier had appropriate porosity and width as the airborne spray was captured within its canopy instead of deflecting up and over it. This article is protected by copyright. All rights reserved.

Notes on drift theory

NASA Technical Reports Server (NTRS)

Burger, R. A.; Moraal, H.; Webb, G. M.

1985-01-01

It is shown that there is a simpler way to derive the average guiding center drift of a distribution of particles than via the so-called single particle analysis. Based on this derivation it is shown that the entire drift formalism can be considerably simplified, and that results for low order anisotropies are more generally valid than is usually appreciated. This drift analysis leads to a natural alternative derivation of the drift velocity along a neutral sheet.