Revealing asymmetries in the HD 181327 debris disk: A recent massive collision or interstellar medium warping

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

Stark, Christopher C.; Kuchner, Marc J.; Schneider, Glenn

New multi-roll coronagraphic images of the HD 181327 debris disk obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope reveal the debris ring in its entirety at high signal-to-noise ratio and unprecedented spatial resolution. We present and apply a new multi-roll image processing routine to identify and further remove quasi-static point-spread function-subtraction residuals and quantify systematic uncertainties. We also use a new iterative image deprojection technique to constrain the true disk geometry and aggressively remove any surface brightness asymmetries that can be explained without invoking dust density enhancements/deficits. The measured empirical scattering phase function for themore » disk is more forward scattering than previously thought and is not well-fit by a Henyey-Greenstein function. The empirical scattering phase function varies with stellocentric distance, consistent with the expected radiation pressured-induced size segregation exterior to the belt. Within the belt, the empirical scattering phase function contradicts unperturbed debris ring models, suggesting the presence of an unseen planet. The radial profile of the flux density is degenerate with a radially varying scattering phase function; therefore estimates of the ring's true width and edge slope may be highly uncertain. We detect large scale asymmetries in the disk, consistent with either the recent catastrophic disruption of a body with mass >1% the mass of Pluto, or disk warping due to strong interactions with the interstellar medium.« less

Revealing Asymmetries in the HD 181327 Debris Disk: A Recent Massive Collision or Interstellar Medium Warping

NASA Astrophysics Data System (ADS)

Stark, Christopher C.; Schneider, Glenn; Weinberger, Alycia J.; Debes, John H.; Grady, Carol A.; Jang-Condell, Hannah; Kuchner, Marc J.

2014-07-01

New multi-roll coronagraphic images of the HD 181327 debris disk obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope reveal the debris ring in its entirety at high signal-to-noise ratio and unprecedented spatial resolution. We present and apply a new multi-roll image processing routine to identify and further remove quasi-static point-spread function-subtraction residuals and quantify systematic uncertainties. We also use a new iterative image deprojection technique to constrain the true disk geometry and aggressively remove any surface brightness asymmetries that can be explained without invoking dust density enhancements/deficits. The measured empirical scattering phase function for the disk is more forward scattering than previously thought and is not well-fit by a Henyey-Greenstein function. The empirical scattering phase function varies with stellocentric distance, consistent with the expected radiation pressured-induced size segregation exterior to the belt. Within the belt, the empirical scattering phase function contradicts unperturbed debris ring models, suggesting the presence of an unseen planet. The radial profile of the flux density is degenerate with a radially varying scattering phase function; therefore estimates of the ring's true width and edge slope may be highly uncertain. We detect large scale asymmetries in the disk, consistent with either the recent catastrophic disruption of a body with mass >1% the mass of Pluto, or disk warping due to strong interactions with the interstellar medium.

The Distribution and Composition Characteristics of Siliceous Rocks from Qinzhou Bay-Hangzhou Bay Joint Belt, South China: Constraint on the Tectonic Evolution of Plates in South China

PubMed Central

Li, Hongzhong; Zhai, Mingguo; Zhang, Lianchang; Zhou, Yongzhang; Yang, Zhijun; He, Junguo; Liang, Jin; Zhou, Liuyu

2013-01-01

The Qinzhou Bay-Hangzhou Bay joint belt is a significant tectonic zone between the Yangtze and Cathaysian plates, where plentiful hydrothermal siliceous rocks are generated. Here, the authors studied the distribution of the siliceous rocks in the whole tectonic zone, which indicated that the tensional setting was facilitating the development of siliceous rocks of hydrothermal genesis. According to the geochemical characteristics, the Neopalaeozoic siliceous rocks in the north segment of the Qinzhou Bay-Hangzhou Bay joint belt denoted its limited width. In comparison, the Neopalaeozoic Qinzhou Bay-Hangzhou Bay joint belt was diverse for its ocean basin in the different segments and possibly had subduction only in the south segment. The ocean basin of the north and middle segments was limited in its width without subduction and possibly existed as a rift trough that was unable to resist the terrigenous input. In the north segment of the Qinzhou Bay-Hangzhou Bay joint belt, the strata of hydrothermal siliceous rocks in Dongxiang copper-polymetallic ore deposit exhibited alternative cycles with the marine volcanic rocks, volcanic tuff, and metal sulphide. These sedimentary systems were formed in different circumstances, whose alternative cycles indicated the release of internal energy in several cycles gradually from strong to weak. PMID:24302882

Screw-fed pump system

DOEpatents

Sprouse, Kenneth M

2014-11-25

A pump system includes a pump that includes a first belt and a second belt that are spaced apart from each other to provide generally straight sides of a passage there between. There is an inlet at one end of the passage and an outlet at an opposite end of the passage, with a passage length that extends between the inlet and the outlet. The passage defines a gap distance in a width direction between the straight sides at the passage inlet. A hopper includes an interior space that terminates at a mouth at the passage inlet. At least one screw is located within the interior space of the hopper and includes a screw diameter in the width direction that is less than or equal to the gap distance.

The linkage between fluvial meander-belt morphodynamics and the depositional record improves paleoenvironmental interpretations, Western Interior Basin, Alberta, Canada

NASA Astrophysics Data System (ADS)

Durkin, P.; Hubbard, S. M.

2016-12-01

Enhanced stratigraphic interpretations are possible when linkages between morphodynamic processes and the depositional record are resolved. Recent studies of modern and ancient meander-belt deposits have emphasized morphodynamic processes that are commonly understated in the analysis of stratigraphic products, such as intra-point bar erosion and rotation, counter-point-bar (concave bank-bench) development and meander-bend abandonment. On a larger scale, longitudinal changes in meander-belt morphology and processes such as changes in meander-bend migration rate, channel-belt width/depth ratio and sinuosity have been observed as rivers flow through the tidal backwater zone. However, few studies have attempted to recognize the impact of the backwater zone in the stratigraphic record. We consider ancient meander-belt deposits of the Cretaceous McMurray Formation and document linkages between morphodynamic processes and their stratigraphic product to resolve more detailed paleoenvironmental interpretations. The ancient meander belt was characterized by paleochannels that were 600 m wide and up to 50 m deep, resolved in a particularly high quality subsurface dataset consisting of 600 km2 of high-quality 3-D seismic data and over 1000 wellbores. A 3-D geocellular model and reconstructed paleochannel migration patterns reveal the evolutionary history of seventeen individual meander belt elements, including point bars, counter point bars and their associated abandoned channel fills. At the meander-bend scale, intra-point-bar erosion surfaces bound accretion packages characterized by unique accretion directions, internal stratigraphic architecture and lithologic properties. Erosion surfaces and punctuated bar rotation are linked to upstream changes in channel planform geometry (meander cut-offs). We provide evidence for downstream translation and development of counter-point bars that formed in response to valley-edge and intra-meander-belt confinement. At the meander-belt scale, analysis of changes in morphology over time reveal a decrease in channel-belt width/thickness ratio and sinuosity, which we attribute to the landward migration of the paleo-backwater limit due to the oncoming and overlying transgression of the Cretaceous Boreal Sea into the Western Interior Basin.

No erosional control on the lateral growth of the Alps

NASA Astrophysics Data System (ADS)

Rosenberg, C. L.; Berger, A.

2009-04-01

On the base of literature data, we estimated the paleowidth of the Central Alps and the changing location of the inferred active fronts of the orogen from the Oligocene to the present. These compilations indicate that the absolute change of width, defined as the distance between the most external, but not necessarily active thrusts of the orogen was modest, amounting to less than 15 %, from 32 Ma to the present. This value lies within the error of estimate, and hence it is no sound evidence for lateral growth or retreat of the orogen. On the other hand the width of the active orogen, defined as the distance between the most external active thrusts, did increase in the early Miocene. This increase started already in the Oligocene as also concluded on the base of sedimentological findings, suggesting a continuous growth of thrusts through the Oligocene-Early Miocene interval (e.g. Schumacher et al., 1996). In the Late Miocene the active width of the Southern Alps decreased, as documented by a pre-Messinian out-of-sequence phase of thrusting (Lecco thrust; Schönborn, 1992) younger than the Milan Belt (Schönborn 1992). Increasing erosion rates are expected to reduce the width of the orogen, whereas decreasing rates are expected to increase its width (Beaumont et al., 1992). Therefore, following the example of previous investigations (Schlunegger et al., 2001; Schlunegger and Simpson, 2002; Willett et al., 2006) we compare the reconstructed changes of width of the Alps with the depositional budgets of the Alpine foreland basins (Kuhlemann, 2000) inferred to be a proxy for the erosion rates of the Alpine belt. This comparison shows that the most significant increases in erosion efficiency do not lead to a decrease in the active width of the orogen. This is indicated by the pronounced foreland-directed growth of the Alps after the Messinian, i.e., during the phase of greatest increase in the erosion rates of the orogen. The best regional examples are the northward shift of the deformation front of the Jura Mountains (Nivière and Winter, 2000; Giamboni et al., 2004; Madritsch et al., 2008), the westward shift of the Chaines Subalpines (Lickorisch and Ford, 1998) on the western side of the orogen, and the southward migration of the active front in the eastern sector of the Southern Alps (Benedetti et al., 2000). The reduced erosional efficiency of the orogen, which started at 17 Ma and continued until the Messinian (Kuhlemann, 2000) also did not coincide to a phase of lateral growth of the orogen. Out-of sequence thrusting in the Southern Alps (Schönborn, 1992) reduced the width of the chain well before the Messinian crisis, i.e. during the phase of fading erosion efficiency. Therefore, erosion does not seem to have been the prime control on the changes of width of the orogen. Alternatively, the effect of erosion on the lateral growth of the orogen can be tested by comparing the timing and the type of shifts of the active deformation front from different parts of the orogen. If climate changes are inferred to control changes in the erosional efficiency of the Alps (Willett et al., 2006), the tectonic response to a given change of climate is expected to be coeval and of similar type in all parts of the chain. This is especially true for an orogen as small as the Alps, whose different portions are all affected by the same climatic conditions. However, the mode of exhumation of the Eastern Alps is very different than that of the Western and Central Alps. The exhumation front progressively shifted towards the foreland in the latter case, whereas it remained focused in the axial zone of the orogen in the former case (Rosenberg and Berger, 2009). As a consequence, a broad metamorphic belt, with cooling ages younging from the axial zone towards the foreland formed in the western Alps, and a narrow metamorphic belt with cooling ages younging towards the axial zone of the orogen formed in the Eastern Alps. These first-order differences indicate that processes other than erosion and climate change controlled the migration of the deformation and exhumation fronts of the Alps. References: Beaumont, C., P. Fullsack, and J. Hamilton (1992). In: K.R. McKlay (ed.), Thrust Tectonics, pp. 19-31, Chapman and Hall, New York. Benedetti, L., P. Tapponnier, G.C.P. King, B. Meyer, and I. Manighetti (2000). J. Geophys. Res., 105, 739-766. Giamboni, M., K. Ustaszewski, S.M. Schmid, M. Schumacher, and A. Wetzel (2004). Int. J. Earth Sci., 93, 207-223. Kuhlemann, J. (2000). Mem. Sci. Geol. Padova, 52, 1-91. Lickorisch, W. H., Ford, M., (1998). In: Mascle et al. (eds.), Cenozoic foreland basin of Western Europe, Geol. Soc. London, Spec. Publ., 134, 189-211. Madritsch, H., S. M. Schmid, and O. Fabbri (2008). Tectonics, 27, TC5005, doi:10.1029/2008TC002282 Rosenberg, C.L. and Berger, A. (2009).Geophysical Research Abstracts, Vol. 11, EGU2009-2906, 2009 EGU General Assembly 2009Schlunegger, F., J. Melzer, and G.E. Tucker (2001). Int. J. Earth Sci., 90, 484-499. Schlunegger, F., and G. Simpson (2002), Geology 30, 907-910. Schönborn, G. (1992) Mem. Scienze Sci. Geolog. Padova, 44, 229-393. Schumacher, M.E., G. Schönborn, D. Bernoulli, and H.P. Laubscher (1996), In: O.A. Pfiffner et al. (eds.), Deep Structure of the Swiss Alps — Results from the National Research Program 20 (NRP 20), 186-204, Birkhäuser, Basel. Willett, S.D., F. Schlunegger, and V. Picotti (2006). Geology, 34, 613-616.

Effectiveness of high school safety belt instruction

DOT National Transportation Integrated Search

1982-12-01

The Effectiveness of High School Safety Belt Instruction was developed during a two-phased project. In Phase I, Focus Group Activities were conducted to determine whether audiovisual safety belt instructional materials assembled by the National Highw...

Do river channels decrease in width downstream on Distributive Fluvial Systems? An evaluation of modern mega-fans

NASA Astrophysics Data System (ADS)

Espinoza, T. N.; Scuderi, L. A.; Weissmann, G. S.; Hartley, A. J.

2014-12-01

Recent studies on aggradational continental sedimentary basins globally show that fluvial deposits in most modern sedimentary basins are dominated Distributive Fluvial Systems (DFS). DFS's are identified by: (1) pattern of channels and floodplain deposits that radiate outward from an apex located where the river enters the sedimentary basin, (2) deposition where an alluvial system becomes unconfined upon entering the sedimentary basin, (3) broadly fan shaped deposit that is convex upward across the DFS and concave upward down-fan, and (4) if the DFS is incised, an intersection point above which the alluvial system is held in an incised valley and below which it distributes sediment across an active depositional lobe. Several papers about DFS hypothesized that rivers on DFS decrease in size down-fan. We are testing this hypothesis through evaluation of LANDSAT and STRM data from large DFS described by Hartley et al (2010). We use ArcGIS to: (1) open the images and merge them together if there are more than one image corresponding to the DFS being studied, (2) use a Maximum Likelihood Analysis in six classes to segment different features on the DFS (e.g. exposed sands, water, vegetation, and other fan environments), (3) isolate the classes that correspond to the active channel belt (e.g., exposed sand bars and water), (4) divide the active channel belt into 1000 m long sections, (5) determine the area of active channel belt in each section, and (6) calculate the average width of the river in each section (e.g., W = area/1000m). We present our result for each DFS river on a graph that shows the change in width downstream. Our final product will be a dataset that contains width versus distance down-fan from the apex for as many of the large DFS from Hartley et al (2010) as possible. If the hypothesis is supported, the decrease in width could have a substantial predictive significance on sandstone geometry in fluvial successions.

Episodic Growth of Fold-Thrust Belts: Insights from Finite Element Modelling

NASA Astrophysics Data System (ADS)

Yang, X.; Peel, F.; Sanderson, D. J.; McNeill, L. C.

2016-12-01

The sequential development of an imbricate thrust system was investigated using a set of 2D FEM models. This study provides new insights on how the style and location of thrust activity changes through cycles of thrust accretion by making refined measurements of the thrust system parameters through time and tracking these parameters through each cycle. In addition to conventional wedge parameters (i.e. surface slope, wedge width and height), the overall taper angle is used to determine how the critical taper angle is reached; a particular focus is on the region of outboard minor horizontal displacement provides insights into the forward propagation of material within, and in front of, the thrust wedge; tracking the position of the failure front (where the frontal thrust roots into the basal detachment) reveals the sequence and advancement of the imbricate thrusts. The model results show that a thrust system is generally composed of three deformation components: thrust wedge, pre-wedge and wedge front. A thrust belt involves growth that repeats episodically and cyclically. When a wedge reaches critical taper ( 10°), thrust movement within the wedge slows while the taper angle and wedge width gradually increase. In contrast, the displacement front (tracked here by the location of 0 m displacement) rapidly propagates forward along whilst the wedge height is fast growing. During this period, the wedge experiences a significant shortening after a new thrust initiates at the failure front, leading to an obvious decrease in wedge width. As soon as the critical taper is achieved, wedge interior (tracked here by the location of 50 m displacement) accelerates forward reducing the taper angle below critical. This is accompanied by a sudden increase in wedge width, slow advancement of displacement front, and slow uplift of the fold-thrust belt. The rapid movements within and in front of the wedge occur alternately. The model results also show that there is clear, although minor, activity (5-10 m displacement) in front of the thrust wedge, which distinguishes the failure front from the displacement front throughout the fold-thrust belt development. This spatial and temporal relationship may not have been previously recognized in natural systems.

A Precise Description of the Hot Classical Belt from the High Lattitude Ecliptic Survey

NASA Astrophysics Data System (ADS)

Petit, Jean-Marc; Kavelaars, John J.; Gladman, Brett; Jones, Lynne; Parker, Joel

2014-11-01

The Canada-France Ecliptic Plane Survey (CFEPS) determined the orbital structure of the Cold classical belt, a component restricted to the semimajor-axis range between the 3:2 and 2:1 mean motion resonances with Neptune. It also showed that the high-inclination component of the inner, main and outer belt form a continuous population, but failed to constrain the inclination distribution itself.The High Latitude survey (HiLat) covered 600 sq.deg. from 15 to 90 deg. ecliptic latitude to address this question. We find that the Brown-like gaussian inclination distribution for each survey separately requires incompatible width of the distribution. Rather, it appears that a gaussian centered on a high (10 to 15 deg.) latitude, à la Gulbis et al. (2010) provides a better match to the observations. We also confirm that the resonant populations have an inclination distribution compatible with a common origin with the Hot component. The hot component itself comes from a constraint q range (35 < q < 41 AU) slightly larger than what some researchers associated with the scattered disk. This enlarged q range place contraints on the eccentricity reached by Neptune in its early history and the duration of this phase.With this more accurate orbital distribution and a refined modelling of the surveys, we present new population estimates of the various populations.

Convective and diffusive ULF wave driven radiation belt electron transport

NASA Astrophysics Data System (ADS)

Degeling, A. W.; Rankin, R.; Elkington, S. R.

2011-12-01

The process of magnetospheric radiation belt electron transport driven by ULF waves is studied using a 2-D ideal MHD model for ULF waves in the equatorial plane including day/night asymmetry and a magnetopause boundary, and a test kinetic model for equatorially mirroring electrons. We find that ULF wave disturbances originating along the magnetopause flanks in the afternoon sector can act to periodically inject phase space density from these regions into the magnetosphere. Closely spaced drift-resonant surfaces for electrons with a given magnetic moment in the presence of the ULF waves create a layer of stochastic dynamics for L-shells above 6.5-7 in the cases examined, extending to the magnetopause. The phase decorrelation time scale for the stochastic region is estimated by the relaxation time for the diffusion coefficient to reach a steady value. This is found to be of the order of 10-15 wave periods, which is commensurate with the typical duration of observed ULF wave packets in the magnetosphere. For L-shells earthward of the stochastic layer, transport is limited to isolated drift-resonant islands in the case of narrowband ULF waves. We examine the effect of increasing the bandwidth of the ULF wave driver by summing together wave components produced by a set of independent runs of the ULF wave model. The wave source spectrum is given a flat-top amplitude of variable width (adjusted for constant power) and random phase. We find that increasing bandwidth can significantly enhance convective transport earthward of the stochastic layer and extend the stochastic layer to lower L-shells.

The Global Statistical Response of the Outer Radiation Belt During Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Murphy, K. R.; Watt, C. E. J.; Mann, I. R.; Jonathan Rae, I.; Sibeck, D. G.; Boyd, A. J.; Forsyth, C. F.; Turner, D. L.; Claudepierre, S. G.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.; Fennell, J.

2018-05-01

Using the total radiation belt electron content calculated from Van Allen Probe phase space density, the time-dependent and global response of the outer radiation belt during storms is statistically studied. Using phase space density reduces the impacts of adiabatic changes in the main phase, allowing a separation of adiabatic and nonadiabatic effects and revealing a clear modality and repeatable sequence of events in storm time radiation belt electron dynamics. This sequence exhibits an important first adiabatic invariant (μ)-dependent behavior in the seed (150 MeV/G), relativistic (1,000 MeV/G), and ultrarelativistic (4,000 MeV/G) populations. The outer radiation belt statistically shows an initial phase dominated by loss followed by a second phase of rapid acceleration, while the seed population shows little loss and immediate enhancement. The time sequence of the transition to the acceleration is also strongly μ dependent and occurs at low μ first, appearing to be repeatable from storm to storm.

Episodic growth of fold-thrust belts: Insights from Finite Element Modelling

NASA Astrophysics Data System (ADS)

Yang, Xiaodong; Peel, Frank J.; Sanderson, David J.; McNeill, Lisa C.

2017-09-01

The sequential development of a fold-thrust belt was investigated using 2D Finite Element Modelling (FEM). The new model results show that a thrust system is typically composed of three distinct regions: the thrust wedge, pre-wedge, and undeformed region. The thrust wedge involves growth that repeats episodically and cyclically. A cycle of wedge building starts as frontal accretion occurs, which is accompanied by a rapid increase in wedge width reducing the taper angle below critical. In response to this, the wedge interior (tracked here by the 50 m displacement position) rapidly propagates forwards into a region of incipient folding. The taper angle progressively increases until it obtains a constant apparent critical value (∼10°). During this period, the wedge experiences significant shortening after a new thrust initiates at the failure front, leading to a decrease in wedge width. Successive widening of the wedge and subsequent shortening and thrusting maintain a reasonably constant taper angle. The fold-thrust belt evolves cyclically, through a combination of rapid advancement of the wedge and subsequent gradual, slow wedge growth. The new model results also highlights that there is clear, although minor, deformation (0-10 m horizontal displacement) in front of the thrust wedge.

Seat and seatbelt accommodation in fire apparatus: Anthropometric aspects

PubMed Central

Hsiao, Hongwei; Whitestone, Jennifer; Wilbur, Michael; Lackore, J. Roger; Routley, J. Gordon

2015-01-01

This study developed anthropometric information on U.S. firefighters to guide fire-apparatus seat and seatbelt designs and future standards development. A stratified sample of 863 male and 88 female firefighters across the U.S. participated in the study. The study results suggested 498 mm in width, 404 mm in depth, and 365–476 mm in height for seat pans; 429–522 mm in width and 542 mm in height for seat back; 871 mm in height for head support; a seat space of 733 mm at shoulder and 678 mm at hip; and a knee/leg clearance of 909 mm in fire truck cab. Also, 1520 mm of lap belt web effective length and 2828 mm of lap-and-shoulder belt web effective length were suggested. These data for firetruck seats and seatbelts provide a foundation for fire apparatus manufacturers and standards committees to improve firefighter seat designs and seatbelt usage compliance. PMID:26154212

Storm-time radiation belt electron dynamics: Repeatability in the outer radiation belt

NASA Astrophysics Data System (ADS)

Murphy, K. R.; Mann, I. R.; Rae, J.; Watt, C.; Boyd, A. J.; Turner, D. L.; Claudepierre, S. G.; Baker, D. N.; Spence, H. E.; Reeves, G. D.; Blake, J. B.; Fennell, J. F.

2017-12-01

During intervals of enhanced solar wind driving the outer radiation belt becomes extremely dynamic leading to geomagnetic storms. During these storms the flux of energetic electrons can vary by over 4 orders of magnitude. Despite recent advances in understanding the nature of competing storm-time electron loss and acceleration processes the dynamic behavior of the outer radiation belt remains poorly understood; the outer radiation belt can exhibit either no change, an enhancement, or depletion in radiation belt electrons. Using a new analysis of the total radiation belt electron content, calculated from the Van Allen probes phase space density (PSD), we statistically analyze the time-dependent and global response of the outer radiation belt during storms. We demonstrate that by removing adiabatic effects there is a clear and repeatable sequence of events in storm-time radiation belt electron dynamics. Namely, the relativistic (μ=1000 MeV/G) and ultra-relativistic (μ=4000 MeV/G) electron populations can be separated into two phases; an initial phase dominated by loss followed by a second phase dominated by acceleration. At lower energies, the radiation belt seed population of electrons (μ=150 MeV/G) shows no evidence of loss but rather a net enhancement during storms. Further, we investigate the dependence of electron dynamics as a function of the second adiabatic invariant, K. These results demonstrate a global coherency in the dynamics of the source, relativistic and ultra-relativistic electron populations as function of the second adiabatic invariant K. This analysis demonstrates two key aspects of storm-time radiation belt electron dynamics. First, the radiation belt responds repeatably to solar wind driving during geomagnetic storms. Second, the response of the radiation belt is energy dependent, relativistic electrons behaving differently than lower energy seed electrons. These results have important implications in radiation belt research. In particular, the repeatability in electron dynamics coupled with observations of processes leading to electron loss (EMIC waves) and acceleration (VLF or ULF waves) can be used to diagnose the relative importance of physical processes in radiation belt dynamics during storms.

Beam Width Robustness of a 670 GHz Imaging Radar

NASA Technical Reports Server (NTRS)

Cooper, K. B.; Llombart, N.; Dengler, R. J.; Siegel, P. H.

2009-01-01

Detection of a replica bomb belt concealed on a mannequin at 4 m standoff range is achieved using a 670 GHz imaging radar. At a somewhat larger standoff range of 4.6 m, the radar's beam width increases substantially, but the through-shirt image quality remains good. This suggests that a relatively modest increase in aperture size over the current design will be sufficient to detect person-borne concealed weapons at ranges exceeding 25 meters.

Along-strike structural variation and thermokinematic development of the Cenozoic Bitlis-Zagros fold-thrust belt, Turkey and Iraqi Kurdistan

NASA Astrophysics Data System (ADS)

Barber, Douglas E.; Stockli, Daniel F.; Koshnaw, Renas I.; Tamar-Agha, Mazin Y.; Yilmaz, Ismail O.

2016-04-01

The Bitlis-Zagros orogen in northern Iraq is a principal element of the Arabia-Eurasia continent collision and is characterized by the lateral intersection of two structural domains: the NW-SE trending Zagros proper system of Iran and the E-W trending Bitlis fold-thrust belt of Turkey and Syria. While these components in northern Iraq share a similar stratigraphic framework, they exhibit along-strike variations in the width and style of tectonic zones, fold morphology and trends, and structural inheritance. However, the distinctions of the Bitlis and Zagros segments remains poorly understood in terms of timing and deformation kinematics as well as first-order controls on fold-thrust development. Structural and stratigraphic study and seismic data combined with low-T thermochronometry provide the basis for reconstructions of the Bitlis-Zagros fold-thrust belt in southeastern Turkey and northern Iraq to elucidate the kinematic and temporal relationship of these two systems. Balanced cross-sections were constructed and incrementally restored to quantify the deformational evolution and use as input for thermokinematic models (FETKIN) to generate thermochronometric ages along the topographic surface of each cross-section line. The forward modeled thermochronometric ages from were then compared to new and previously published apatite and zircon (U-Th)/He and fission-track ages from southeastern Turkey and northern Iraq to test the validity of the timing, rate, and fault-motion geometry associated with each reconstruction. The results of these balanced theromokinematic restorations integrated with constraints from syn-tectonic sedimentation suggest that the Zagros belt between Erbil and Suleimaniyah was affected by an initial phase of Late Cretaceous exhumation related to the Proto-Zagros collision. During the main Zagros phase, deformation advanced rapidly and in-sequence from the Main Zagros Fault to the thin-skinned frontal thrusts (Kirkuk, Shakal, Qamar) from middle to latest Miocene times, followed by out-of-sequence development of the Mountain Front Flexure (Qaradagh anticline) by ~5 Ma. In contrast, initial exhumation in the northern Bitlis belt occurred by mid-Eocene time, followed by collisional deformation that propagated southward into northern Iraqi Kurdistan during the middle to late Miocene. Plio-Pleistocene deformation was partitioned into out-of-sequence reactivation of the Ora thrust along the Iraq-Turkey border, concurrent with development of the Sinjar and Abdulaziz inversion structures at the edge of the Bitlis deformation front. Overall, these data suggest the Bitlis and Zagros trends evolved relatively independently during Cretaceous and early Cenozoic times, resulting in very different structural and stratigraphic inheritance, before being affected contemporaneously by major phase of in-sequence shortening during middle to latest Miocene and out-of-sequence deformation since the Pliocene. Limited seismic sections corroborate the notion that the structural style and trend of the Bitlis fold belt is dominated by inverted Mesozoic extensional faults, whereas the Zagros structures are interpreted mostly as fault-propagation folds above a Triassic décollement. These pre-existing heterogeneities in the Bitlis contributed to the lower shortening estimates, variable anticline orientation, and irregular fold spacing and the fundamentally different orientations of the Zagros-Bitlis belt in Iraqi Kurdistan and Turkey.

Design Optimization of Liquid Nitrogen Based IQF Tunnel

NASA Astrophysics Data System (ADS)

Datye, A. B.; Narayankhedkar, K. G.; Sharma, G. K.

2006-04-01

A design methodology for an Individual Quick Freezing (IQF) tunnel using liquid nitrogen is developed and the design based on this methodology is validated using the data of commercial tunnels. The design takes care of heat gains due to the conveyor belt which is exposed to atmosphere at the infeed and outfeed ends. The design also considers the heat gains through the insulation as well as due to circulating fans located within the tunnel. For minimum liquid nitrogen consumption, the ratio of the length of the belt, L (from infeed to out feed) to the width of the belt, W can be considered as a parameter. The comparison of predicted and reported liquid nitrogen (experimental data) consumption shows good agreement and is within 10 %.

Combined Global MHD and Test-Particle Simulation of a Radiation Belt Storm: Comparing Depletion, Recovery and Enhancement with in Situ Measurements

NASA Astrophysics Data System (ADS)

Sorathia, K.; Ukhorskiy, A. Y.; Merkin, V. G.; Wiltberger, M. J.; Lyon, J.; Claudepierre, S. G.; Fennell, J. F.

2017-12-01

During geomagnetic storms the intensities of radiation belt electrons exhibit dramatic variability. In the main phase electron intensities exhibit deep depletion over a broad region of the outer belt. The intensities then increase during the recovery phase, often to levels that significantly exceed their pre-storm values. In this study we analyze the depletion, recovery and enhancement of radiation belt intensities during the 2013 St. Patrick's geomagnetic storm. We simulate the dynamics of high-energy electrons using our newly-developed test-particle radiation belt model (CHIMP) based on a hybrid guiding-center/Lorentz integrator and electromagnetic fields derived from high-resolution global MHD (LFM) simulations. Our approach differs from previous work in that we use MHD flow information to identify and seed test-particles into regions of strong convection in the magnetotail. We address two science questions: 1) what are the relative roles of magnetopause losses, transport-driven atmospheric precipitation, and adiabatic cooling in the radiation belt depletion during the storm main phase? and 2) to what extent can enhanced convection/mesoscale injections account for the radiation belt buildup during the recovery phase? Our analysis is based on long-term model simulation and the comparison of our model results with electron intensity measurements from the MAGEIS experiment of the Van Allen Probes mission.

Improved electroacoustic dewatering (EAD) belt press for food products. Phase 3, Technical progress report

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

Not Available

1994-02-01

Battelle`s electroacoustic dewatering (EAD) process improves the performance of mechanical dewatering processes for several food products (such as corn fiber) by superimposing electric and ultrasonic fields. EAD has the potential to save 0.027 to 0.035 quad/yr energy by 1995 in the food processing industry, which consumed 0.15 to 0.18 quad in 1986. This report covers Phase III for demonstrating the EAD prototype on corn wet milling products (corn fiber and gluten); only Task 1 (prototype preparation and planning) was completed. EAD performance was examined in the laboratory; availability of a test site was examined. The single-roll, postdewatering EAD belt pressmore » prototype can accept material predewatered by a screw press, centrifuge, or any other mechanical dewatering device. The two-belt system, utilizing a copper-polymer cathode belt, performed as well as the three-belt system used in Phase II.« less

Participative education for children: an effective approach to increase safety belt use.

PubMed Central

Lehman, G R; Geller, E S

1990-01-01

Vehicle license plate numbers and the shoulder belt use of front-seat occupants were recorded unobtrusively when parents delivered and picked up their children at a Montessori school during 5-day baseline, intervention, and follow-up phases. Practicing and presenting a 15-min safety belt skit increased the safety belt use of those 6 kindergarten children who were not consistent belt users 82% above their preintervention baseline belt use mean of 47%. The belt use of these children's parents (who watched the skit) increased to 56% above their baseline mean of 36%. Also, mean safety belt use of 11 primary school children who watched the skit increased to 70% above their baseline of 28%. Mean safety belt use of the older children's parents (who didn't watch the skit) remained at approximately 31% for each phase, regardless of whether children were vehicle occupants. The follow-up observations, taken 3 months after the intervention, revealed 60% belt use for the kindergartners, 48% for the primary school children, and 71% for the kindergartners' parents when the children were vehicle occupants but only 30% when the parents were driving alone. PMID:2373658

Seat and seatbelt accommodation in fire apparatus: Anthropometric aspects.

PubMed

Hsiao, Hongwei; Whitestone, Jennifer; Wilbur, Michael; Lackore, J Roger; Routley, J Gordon

2015-11-01

This study developed anthropometric information on U.S. firefighters to guide fire-apparatus seat and seatbelt designs and future standards development. A stratified sample of 863 male and 88 female firefighters across the U.S. participated in the study. The study results suggested 498 mm in width, 404 mm in depth, and 365-476 mm in height for seat pans; 429-522 mm in width and 542 mm in height for seat back; 871 mm in height for head support; a seat space of 733 mm at shoulder and 678 mm at hip; and a knee/leg clearance of 909 mm in fire truck cab. Also, 1520 mm of lap belt web effective length and 2828 mm of lap-and-shoulder belt web effective length were suggested. These data for fire-truck seats and seatbelts provide a foundation for fire apparatus manufacturers and standards committees to improve firefighter seat designs and seatbelt usage compliance. Published by Elsevier Ltd.

Analysis of Fault Spacing in Thrust-Belt Wedges Using Numerical Modeling

NASA Astrophysics Data System (ADS)

Regensburger, P. V.; Ito, G.

2017-12-01

Numerical modeling is invaluable in studying the mechanical processes governing the evolution of geologic features such as thrust-belt wedges. The mechanisms controlling thrust fault spacing in wedges is not well understood. Our numerical model treats the thrust belt as a visco-elastic-plastic continuum and uses a finite-difference, marker-in-cell method to solve for conservation of mass and momentum. From these conservation laws, stress is calculated and Byerlee's law is used to determine the shear stress required for a fault to form. Each model consists of a layer of crust, initially 3-km-thick, carried on top of a basal décollement, which moves at a constant speed towards a rigid backstop. A series of models were run with varied material properties, focusing on the angle of basal friction at the décollement, the angle of friction within the crust, and the cohesion of the crust. We investigate how these properties affected the spacing between thrusts that have the most time-integrated history of slip and therefore have the greatest effect on the large-scale undulations in surface topography. The surface position of these faults, which extend through most of the crustal layer, are identifiable as local maxima in positive curvature of surface topography. Tracking the temporal evolution of faults, we find that thrust blocks are widest when they first form at the front of the wedge and then they tend to contract over time as more crustal material is carried to the wedge. Within each model, thrust blocks form with similar initial widths, but individual thrust blocks develop differently and may approach an asymptotic width over time. The median of thrust block widths across the whole wedge tends to decrease with time. Median fault spacing shows a positive correlation with both wedge cohesion and internal friction. In contrast, median fault spacing exhibits a negative correlation at small angles of basal friction (<17˚) and a positive correlation with larger angles of basal friction. From these correlations, we will derive scaling laws that can be used to predict fault spacing in thrust-belt wedges.

Adaptive control of dynamic balance in human gait on a split-belt treadmill.

PubMed

Buurke, Tom J W; Lamoth, Claudine J C; Vervoort, Danique; van der Woude, Lucas H V; den Otter, Rob

2018-05-17

Human bipedal gait is inherently unstable and staying upright requires adaptive control of dynamic balance. Little is known about adaptive control of dynamic balance in reaction to long-term, continuous perturbations. We examined how dynamic balance control adapts to a continuous perturbation in gait, by letting people walk faster with one leg than the other on a treadmill with two belts (i.e. split-belt walking). In addition, we assessed whether changes in mediolateral dynamic balance control coincide with changes in energy use during split-belt adaptation. In nine minutes of split-belt gait, mediolateral margins of stability and mediolateral foot roll-off changed during adaptation to the imposed gait asymmetry, especially on the fast side, and returned to baseline during washout. Interestingly, no changes in mediolateral foot placement (i.e. step width) were found during split-belt adaptation. Furthermore, the initial margin of stability and subsequent mediolateral foot roll-off were strongly coupled to maintain mediolateral dynamic balance throughout the gait cycle. Consistent with previous results net metabolic power was reduced during split-belt adaptation, but changes in mediolateral dynamic balance control were not correlated with the reduction of net metabolic power during split-belt adaptation. Overall, this study has shown that a complementary mechanism of relative foot positioning and mediolateral foot roll-off adapts to continuously imposed gait asymmetry to maintain dynamic balance in human bipedal gait. © 2018. Published by The Company of Biologists Ltd.

Seat belt, DWI, and other traffic violations among recent immigrants in Florida and Tennessee.

DOT National Transportation Integrated Search

2013-05-01

Phase I of this project identified two States, Florida and Tennessee, that maintain information on drivers traffic violations and residency status. : Phase II analyzed State databases to examine seat belt nonuse, DWI, and other traffic safety viol...

Density (DE)

Treesearch

John F. Caratti

2006-01-01

The FIREMON Density (DE) method is used to assess changes in plant species density and height for a macroplot. This method uses multiple quadrats and belt transects (transects having a width) to sample within plot variation and quantify statistically valid changes in plant species density and height over time. Herbaceous plant species are sampled with quadrats while...

Motivation of employers to encourage their employees to use safety belts (Phase 1)

DOT National Transportation Integrated Search

1982-05-01

For the purpose of motivating employers to encourage their employees to use safety belts, a manual for employers, "The Profit in Safety Belts: A View for Employers", is developed. The manual brings to the attention of employers the various cost eleme...

The Togo-Benin-Nigeria Shield: evidence of crustal aggregation in the Pan-African belt

NASA Astrophysics Data System (ADS)

Ajibade, A. C.; Wright, J. B.

1989-08-01

The importance of "suspect" or "exotic" (i.e. allochthonous) terranes as a major element in collisional orogenic belts is becoming well established. We propose that the southern Pan-African domain in West Africa is an aggregation or " mosaic" of island arcs, interarc (ensimatic) basins and continental fragments. A fracture zone in northwestern Nigeria, already identified as a possible crustal suture, is shown to separate two contrasted basement terranes. Elsewhere in the shield are flat-lying structures characteristic of those associated with crustal convergence, lying within or near to major fractures. Many small ultramafic/mafic bodies occur in the shield and some of them may be remnants of ophiolites caught up in suture zones. An aggregation of allochthonous terranes (island arcs, sedimentary basins and continental blocks) would help to explain: (a) the great width of the Pan-African belt; (b) the spread of ages within the "Pan-African" range (c. 750-450 Ma), also the relict Liberian and Eburnian ages (c. 2700 and 2000 Ma respectively); and the enigmatic Kibaran "event" (c. 1100 Ma); (c) the contrasted volcano-sedimentary characteristics of the different supracrustal belts.

Geochemical evidence for a brooks range mineral belt, Alaska

USGS Publications Warehouse

Marsh, S.P.; Cathrall, J.B.

1981-01-01

Geochemical studies in the central Brooks Range, Alaska, delineate a regional, structurally controlled mineral belt in east-west-trending metamorphic rocks and adjacent metasedimentary rocks. The mineral belt extends eastward from the Ambler River quadrangle to the Chandalar and Philip Smith quadrangles, Alaska, from 147?? to 156??W. longitude, a distance of more than 375 km, and spans a width from 67?? to 69??N. latitude, a distance of more than 222 km. Within this belt are several occurrences of copper and molybdenum mineralization associated with meta-igneous, metasedimentary, and metavolcanic rocks; the geochemical study delineates target areas for additional occurrences. A total of 4677 stream-sediment and 2286 panned-concentrate samples were collected in the central Brooks Range, Alaska, from 1975 to 1979. The -80 mesh ( 2.86) nonmagnetic fraction of the panned concentrates from stream sediment were analyzed by semiquantitative spectrographic methods. Two geochemical suites were recognized in this investigation; a base-metal suite of copper-lead-zinc and a molybdenum suite of molybdenum-tin-tungsten. These suites suggest several types of mineralization within the metamorphic belt. Anomalies in molybdenum with associated Cu and W suggest a potential porphyry molybdenum system associated with meta-igneous rocks. This regional study indicates that areas of metaigneous rocks in the central metamorphic belt are target areas for potential mineralized porphyry systems and that areas of metavolcanic rocks are target areas for potential massive sulfide mineralization. ?? 1981.

Mining The Sdss-moc Database For Main-belt Asteroid Solar Phase Behavior.

NASA Astrophysics Data System (ADS)

Truong, Thien-Tin; Hicks, M. D.

2010-10-01

The 4th Release of the Sloan Digital Sky Survey Moving Object Catalog (SDSS-MOC) contains 471569 moving object detections from 519 observing runs obtained up to March 2007. Of these, 220101 observations were linked with 104449 known small bodies, with 2150 asteroids sampled at least 10 times. It is our goal to mine this database in order to extract solar phase curve information for a large number of main-belt asteroids of different dynamical and taxonomic classes. We found that a simple linear phase curve fit allowed us to reject data contaminated by intrinsic rotational lightcurves and other effects. As expected, a running mean of solar phase coefficient is strongly correlated with orbital elements, with the inner main-belt dominated by bright S-type asteroids and transitioning to darker C and D-type asteroids with steeper solar phase slopes. We shall fit the empirical H-G model to our 2150 multi-sampled asteroids and correlate these parameters with spectral type derived from the SDSS colors and position within the asteroid belt. Our data should also allow us to constrain solar phase reddening for a variety of taxonomic classes. We shall discuss errors induced by the standard "g=0.15" assumption made in absolute magnitude determination, which may slightly affect number-size distribution models.

Effect of Maximal Apnoea Easy-Going and Struggle Phases on Subarachnoid Width and Pial Artery Pulsation in Elite Breath-Hold Divers.

PubMed

Winklewski, Pawel J; Barak, Otto; Madden, Dennis; Gruszecka, Agnieszka; Gruszecki, Marcin; Guminski, Wojciech; Kot, Jacek; Frydrychowski, Andrzej F; Drvis, Ivan; Dujic, Zeljko

2015-01-01

The aim of the study was to assess changes in subarachnoid space width (sas-TQ), the marker of intracranial pressure (ICP), pial artery pulsation (cc-TQ) and cardiac contribution to blood pressure (BP), cerebral blood flow velocity (CBFV) and cc-TQ oscillations throughout the maximal breath hold in elite apnoea divers. Non-invasive assessment of sas-TQ and cc-TQ became possible due to recently developed method based on infrared radiation, called near-infrared transillumination/backscattering sounding (NIR-T/BSS). The experimental group consisted of seven breath-hold divers (six men). During testing, each participant performed a single maximal end-inspiratory breath hold. Apnoea consisted of the easy-going and struggle phases (characterised by involuntary breathing movements (IBMs)). Heart rate (HR) was determined using a standard ECG. BP was assessed using the photoplethysmography method. SaO2 was monitored continuously with pulse oximetry. A pneumatic chest belt was used to register thoracic and abdominal movements. Cerebral blood flow velocity (CBFV) was estimated by a 2-MHz transcranial Doppler ultrasonic probe. sas-TQ and cc-TQ were measured using NIR-T/BSS. Wavelet transform analysis was performed to assess cardiac contribution to BP, CBFV and cc-TQ oscillations. Mean BP and CBFV increased compared to baseline at the end of the easy phase and were further augmented by IBMs. cc-TQ increased compared to baseline at the end of the easy phase and remained stable during the IBMs. HR did not change significantly throughout the apnoea, although a trend toward a decrease during the easy phase and recovery during the IBMs was visible. Amplitudes of BP, CBFV and cc-TQ were augmented. sas-TQ and SaO2 decreased at the easy phase of apnoea and further decreased during the IBMs. Apnoea increases intracranial pressure and pial artery pulsation. Pial artery pulsation seems to be stabilised by the IBMs. Cardiac contribution to BP, CBFV and cc-TQ oscillations does not change throughout the apnoea.

Geodetic Insights into the Earthquake Cycle in a Fold and Thrust Belt

NASA Astrophysics Data System (ADS)

Ingleby, T. F.; Wright, T. J.; Butterworth, V.; Weiss, J. R.; Elliott, J.

2017-12-01

Geodetic measurements are often sparse in time (e.g. individual interferograms) and/or space (e.g. GNSS stations), adversely affecting our ability to capture the spatiotemporal detail required to study the earthquake cycle in complex tectonic systems such as subaerial fold and thrust belts. In an effort to overcome these limitations we combine 3 generations of SAR satellite data (ERS 1/2, Envisat & Sentinel-1a/b) to obtain a 25 year, high-resolution surface displacement time series over the frontal portion of an active fold and thrust belt near Quetta, Pakistan where a Mw 7.1 earthquake doublet occurred in 1997. With these data we capture a significant portion of the seismic cycle including the interseismic, coseismic and postseismic phases. Each satellite time series has been referenced to the first ERS-1 SAR epoch by fitting a ground deformation model to the data. This allows us to separate deformation associated with each phase and to examine their relative roles in accommodating strain and creating topography, and to explore the relationship between the earthquake cycle and critical taper wedge mechanics. Modeling of the coseismic deformation suggests a long, thin rupture with rupture length 7 times greater than rupture width. Rupture was confined to a 20-30 degree north-northeast dipping reverse fault or ramp at depth, which may be connecting two weak decollements at approximately 8 km and 13 km depth. Alternatively, intersections between the coseismic fault plane and pre-existing steeper splay faults underlying folds may have played a significant role in inhibiting rupture, as evidenced by intersection points bordering the rupture. These fault intersections effectively partition the fault system down-dip and enable long, thin ruptures. Postseismic deformation is manifest as uplift across short-wavelength folds at the thrust front, with displacement rates decreasing with time since the earthquake. Broader patterns of postseismic uplift are also observed surrounding the coseismic rupture in both the down- and up-dip directions. We examine how coseismic stress changes may be driving the postseismic deformation by jointly inverting the InSAR-derived displacements for the rupture and fault friction parameters using a rate-strengthening friction model.

New Horizons High-Phase Observations of Distant Kuiper Belt Objects

NASA Astrophysics Data System (ADS)

Verbiscer, A.; Porter, S.; Spencer, J. R.; Buie, M. W.; Benecchi, S.; Weaver, H. A., Jr.; Buratti, B. J.; Ennico Smith, K.; Olkin, C.; Stern, S. A.; Young, L. A.; Cheng, A. F.

2017-12-01

From its unique vantage point far from the Sun, NASA's New Horizons spacecraft has observed Kuiper Belt Objects at separations ranging from 0.1 to 70 AU, and at solar phase angles far larger than those attainable from Earth. We have constructed the first KBO solar phase curves with substantial phase angle coverage for targets including Haumea, Makemake, Quaoar, Arawn (Porter et al. 2016, Astrophys. J. Lett. 828, L15), and 2002 MS4. We compare the phase functions of these KBOs with those of objects in the Pluto system and other Solar System bodies such as comets, asteroids, and icy satellites. For KBOs with known geometric albedos, these measurements enable calculation of the phase integral, an important photometric property that characterizes the energy balance on a distant KBO surface. During its approach to 2014 MU69, and following its close encounter on 1 January 2019, New Horizons will continue to exploit its capabilities as NASA's only observatory within the Kuiper Belt itself.

Powerful conveyer belt real-time online detection system based on x-ray

NASA Astrophysics Data System (ADS)

Rong, Feng; Miao, Chang-yun; Meng, Wei

2009-07-01

The powerful conveyer belt is widely used in the mine, dock, and so on. After used for a long time, internal steel rope of the conveyor belt may fracture, rust, joints moving, and so on .This would bring potential safety problems. A kind of detection system based on x-ray is designed in this paper. Linear array detector (LDA) is used. LDA cost is low, response fast; technology mature .Output charge of LDA is transformed into differential voltage signal by amplifier. This kind of signal have great ability of anti-noise, is suitable for long-distance transmission. The processor is FPGA. A IP core control 4-channel A/D convertor, achieve parallel output data collection. Soft-core processor MicroBlaze which process tcp/ip protocol is embedded in FPGA. Sampling data are transferred to a computer via Ethernet. In order to improve the image quality, algorithm of getting rid of noise from the measurement result and taking gain normalization for pixel value is studied and designed. Experiments show that this system work well, can real-time online detect conveyor belt of width of 2.0m and speed of 5 m/s, does not affect the production. Image is clear, visual and can easily judge the situation of conveyor belt.

Silviculture's role in managing boreal forests

Treesearch

Russell T. Graham; Theresa B. Jain

1998-01-01

Boreal forests, which are often undeveloped, are a major source of raw materials for many countries. They are circumpolar in extent and occupy a belt to a width of 1000 km in certain regions. Various conifer and hardwood species ranging from true firs to poplars grow in boreal forests. These species exhibit a wide range of shade tolerance and growth characteristics,...

Quasi-relativistic electron precipitation due to interactions with coherent VLF waves in the magnetosphere

NASA Technical Reports Server (NTRS)

Chang, H. C.; Inan, U. S.

1983-01-01

The equations of motion for the cyclotron resonance interaction between coherent whistler mode waves and energetic particles are rederived with the inclusion of relativistic effects. The pitch angle scattering of the near-loss-cone quasi-relativistic electrons trapped in the magnetosphere is studied using a test particle method employing these relativistic equations, and the precipitated energy spectrum due to the wave-induced perturbations of a full distribution of particles is computed. Results show that the full width at half maximum peak width of the rms scattering pattern of the near-loss-cone particles would give an upper bound to the peak width of the associated precipitated energy spectrum under the conditions of moderate wave intensities in the low L shell region. In addition, it is found that the peak widths are within the upper limit values measured by recent satellite experiments. It is concluded that interactions of inner radiation belt particles with monochromatic waves could produce precipitated fluxes with relatively sharp spectral widths, and that therefore the L-dependent narrow peaks observed by low altitude satellite particle detectors could be caused by such interactions.

Lower extremity sagittal joint moment production during split-belt treadmill walking

PubMed Central

Roemmich, Ryan T.; Stegemöller, Elizabeth L.; Hass, Chris J.

2012-01-01

The split-belt treadmill (SBT) has recently been used to rehabilitate locomotor asymmetries in clinical populations. However, the joint mechanics produced while walking on a SBT are not well-understood. The purpose of this study was to investigate the lower extremity sagittal joint moments produced by each limb during SBT walking and provide insight as to how these joint moment patterns may be useful in rehabilitating unilateral gait deficits. Thirteen healthy young volunteers walked on the SBT with the belts tied and in a “SPLIT” session in which one belt moved twice as fast as the other. Sagittal lower extremity joint moment and ground reaction force impulses were then calculated over the braking and propulsive phases of the gait cycle. Paired t-tests were performed to analyze magnitude differences between conditions (i.e. the fast and slow limbs during SPLIT vs. the same limb during tied-belt walking) and between the fast and slow limbs during SPLIT. During the SPLIT session, the fast limb produced higher ground reaction force and ankle moment impulses during the propulsive and braking phases, and lower knee moment impulses during the propulsive phase when compared to the slow limb. The knee moment impulse was also significantly higher during braking in the slow limb than in the fast limb. The mechanics of each limb during the SPLIT session also differed from the mechanics observed when the belt speeds were tied. Based on these findings, we suggest that each belt may have intrinsic value in rehabilitating specific unilateral locomotor deficits. PMID:22985473

A method for automated control of belt velocity changes with an instrumented treadmill.

PubMed

Hinkel-Lipsker, Jacob W; Hahn, Michael E

2016-01-04

Increased practice difficulty during asymmetrical split-belt treadmill rehabilitation has been shown to improve gait outcomes during retention and transfer tests. However, research in this area has been limited by manual treadmill operation. In the case of variable practice, which requires stride-by-stride changes to treadmill belt velocities, the treadmill control must be automated. This paper presents a method for automation of asymmetrical split-belt treadmill walking, and evaluates how well this method performs with regards to timing of gait events. One participant walked asymmetrically for 100 strides, where the non-dominant limb was driven at their self-selected walking speed, while the other limb was driven randomly on a stride-by-stride basis. In the control loop, the key factors to insure that the treadmill belt had accelerated to its new velocity safely during the swing phase were the sampling rate of the A/D converter, processing time within the controller software, and acceleration of the treadmill belt. The combination of these three factors resulted in a total control loop time during each swing phase that satisfied these requirements with a factor of safety that was greater than 4. Further, a polynomial fit indicated that belt acceleration was the largest contributor to changes in this total time. This approach appears to be safe and reliable for stride-by-stride adjustment of treadmill belt speed, making it suitable for future asymmetrical split-belt walking studies. Further, it can be incorporated into virtual reality rehabilitation paradigms that utilize split-belt treadmill walking. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modulation of phase durations, phase variations, and temporal coordination of the four limbs during quadrupedal split-belt locomotion in intact adult cats

PubMed Central

D'Angelo, Giuseppe; Thibaudier, Yann; Telonio, Alessandro; Hurteau, Marie-France; Kuczynski, Victoria; Dambreville, Charline

2014-01-01

Stepping along curvilinear paths produces speed differences between the inner and outer limb(s). This can be reproduced experimentally by independently controlling left and right speeds with split-belt locomotion. Here we provide additional details on the pattern of the four limbs during quadrupedal split-belt locomotion in intact cats. Six cats performed tied-belt locomotion (same speed bilaterally) and split-belt locomotion where one side (constant side) stepped at constant treadmill speed while the other side (varying side) stepped at several speeds. Cycle, stance, and swing durations changed in parallel in homolateral limbs with shorter and longer stance and swing durations on the fast side, respectively, compared with the slow side. Phase variations were quantified in all four limbs by measuring the slopes of the regressions between stance and cycle durations (rSTA) and between swing and cycle durations (rSW). For a given limb, rSTA and rSW were not significantly different from one another on the constant side whereas on the varying side rSTA increased relative to tied-belt locomotion while rSW became more negative. Phase variations were similar for homolateral limbs. Increasing left-right speed differences produced a large increase in homolateral double support on the slow side, while triple-support periods decreased. Increasing left-right speed differences altered homologous coupling, homolateral coupling on the fast side, and coupling between the fast hindlimb and slow forelimb. Results indicate that homolateral limbs share similar control strategies, only certain features of the interlimb pattern adjust, and spinal locomotor networks of the left and right sides are organized symmetrically. PMID:25031257

The behavioral impact of an advertising campaign to promote safety belt use.

PubMed

Cope, J G; Moy, S S; Grossnickle, W F

1988-01-01

Safety belt use was observed at one restaurant during McDonald's "Make It Click" promotional campaign. Following baseline, the program was monitored without intervention. During the final 2 weeks of the campaign an incentive strategy was added providing a large soft drink contingent on safety belt use. Safety belt use did not change from baseline levels before the incentive phase. The rate of belt use increased under contingent reward and declined during follow-up. The effects of a verbal prompt could not be assessed because of the almost nonexistent use of the "Make It Click" stickers throughout the study.

Impact of an interbedded viscous décollement on the structural and kinematic coupling in fold-and-thrust belts: Insights from analogue modeling

NASA Astrophysics Data System (ADS)

Borderie, Sandra; Graveleau, Fabien; Witt, César; Vendeville, Bruno C.

2018-01-01

Fold-and-thrust belts (FTBs) can be segmented both across and along strike because of various factors including tectonic and stratigraphic inheritance. In this study, we investigated along/across-strike structural interactions in a FTB propagating toward a foreland which displays contrasted lithological sequences. A set of analogue models was performed in a compressional box where a single viscous level of varying width was interbedded within a frictional series. The tectonic interaction between the viscous and the frictional provinces was tested both along and across strike. Results indicate that a frictional province influences the along-strike tectonic evolution of an adjacent viscous province. This influence decreases when the width of the viscous province increases. The frictional provinces control the taper, structural style, obliquity of the structures' trend and kinematics of the shallow deformation front of the viscous province. Results evidence how far a frictional province can impact the deformation of an adjacent viscous province. For frictional-viscous wedges, it appears that the critical taper theory, which is generally applied in 2-D, should be likely considered in terms of 3-D. Moreover, the kinematics of the deep deformation front shows mutual influences between the adjacent viscous and frictional provinces. Experimental results are compared to natural examples in the Kuqa Basin (Southern Tian Shan, China) and the Salt Range (Pakistan), and give an insight to a better understanding of the dynamics of fold-and-thrust belts bearing a viscous décollement, such as salt.

Simulating the Outer Radiation Belt During the Rising Phase of Solar Cycle 24

NASA Technical Reports Server (NTRS)

Fok, Mei-Ching; Glocer, Alex; Zheng, Qiuhua; Chen, Sheng-Hsien; Kanekal, Shri; Nagai, Tsungunobu; Albert, Jay

2011-01-01

After prolonged period of solar minimum, there has been an increase in solar activity and its terrestrial consequences. We are in the midst of the rising phase of solar cycle 24, which began in January 2008. During the initial portion of the cycle, moderate geomagnetic storms occurred follow the 27 day solar rotation. Most of the storms were accompanied by increases in electron fluxes in the outer radiation belt. These enhancements were often preceded with rapid dropout at high L shells. We seek to understand the similarities and differences in radiation belt behavior during the active times observed during the of this solar cycle. This study includes extensive data and simulations our Radiation Belt Environment Model. We identify the processes, transport and wave-particle interactions, that are responsible for the flux dropout and the enhancement and recovery.

Children in crashes: mechanisms of injury and restraint systems

PubMed Central

Lapner, Peter C.; McKay, Morag; Howard, Andrew; Gardner, Bill; German, Alan; Letts, Mervyn

2001-01-01

Objectives To explore the levels of protection offered to children involved in motor vehicle collisions. Design A joint study by the Children’s Hospital of Eastern Ontario (CHEO) and Transport Canada, Ottawa, conducted in 2 phases: retrospective from 1990 to 1997 and prospective from 1998 to 2000. Setting CHEO, a university affiliated tertiary care centre. Patients Children admitted to CHEO between 1990 and 2000 with spinal trauma due to motor vehical crashes (MVCs). Phase 1 of the study involved analysis, in a series of 45 children after MVAs, by location of spinal injury versus belt type. Phase 2 was a prospective study of 22 children injured in 15 MVAs. Interventions A biomechanical assessment of the vehicle and its influence on the injuries sustained. Main outcome measures The nature and extent of the injuries sustained, and the vehicle dynamics and associated occupant kinematics. Results The odds ratio of sustaining a spinal injury while wearing a 2-point belt versus a 3-point belt was 24 (95% confidence interval 2.0–2.45, p < 0.1), indicating a much higher incidence with a lap belt than a shoulder strap. Conclusions Proper seat-belt restraint reduces the morbidity in children involved in MVCs. Children under the age of 12 years should not be front-seat passengers until the sensitivity of air bags has been improved. Three-point pediatric seat belts should be available for family automobiles to reduce childhood trauma in MVCs. PMID:11764879

Rapid Loss of Radiation Belt Relativistic Electrons by EMIC Waves

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

Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan

How relativistic electrons are lost is an important question surrounding the complex dynamics of the Earth's outer radiation belt. Radial loss to the magnetopause and local loss to the atmosphere are two main competing paradigms. Here on the basis of the analysis of a radiation belt storm event on 27 February 2014, we present new evidence for the electromagnetic ion cyclotron (EMIC) wave-driven local precipitation loss of relativistic electrons in the heart of the outer radiation belt. During the main phase of this storm, the radial profile of relativistic electron phase space density was quasi-monotonic, qualitatively inconsistent with the predictionmore » of radial loss theory. The local loss at low L shells was required to prevent the development of phase space density peak resulting from the radial loss process at high L shells. The rapid loss of relativistic electrons in the heart of outer radiation belt was observed as a dip structure of the electron flux temporal profile closely related to intense EMIC waves. Our simulations further confirm that the observed EMIC waves within a quite limited longitudinal region were able to reduce the off-equatorially mirroring relativistic electron fluxes by up to 2 orders of magnitude within about 1.5 h.« less

Rapid Loss of Radiation Belt Relativistic Electrons by EMIC Waves

DOE PAGES

Su, Zhenpeng; Gao, Zhonglei; Zheng, Huinan; ...

2017-08-31

How relativistic electrons are lost is an important question surrounding the complex dynamics of the Earth's outer radiation belt. Radial loss to the magnetopause and local loss to the atmosphere are two main competing paradigms. Here on the basis of the analysis of a radiation belt storm event on 27 February 2014, we present new evidence for the electromagnetic ion cyclotron (EMIC) wave-driven local precipitation loss of relativistic electrons in the heart of the outer radiation belt. During the main phase of this storm, the radial profile of relativistic electron phase space density was quasi-monotonic, qualitatively inconsistent with the predictionmore » of radial loss theory. The local loss at low L shells was required to prevent the development of phase space density peak resulting from the radial loss process at high L shells. The rapid loss of relativistic electrons in the heart of outer radiation belt was observed as a dip structure of the electron flux temporal profile closely related to intense EMIC waves. Our simulations further confirm that the observed EMIC waves within a quite limited longitudinal region were able to reduce the off-equatorially mirroring relativistic electron fluxes by up to 2 orders of magnitude within about 1.5 h.« less

SOLAR MERIDIONAL FLOW IN THE SHALLOW INTERIOR DURING THE RISING PHASE OF CYCLE 24

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

Zhao, Junwei; Bogart, R. S.; Kosovichev, A. G.

2014-07-01

Solar subsurface zonal- and meridional-flow profiles during the rising phase of solar cycle 24 are studied using the time-distance helioseismology technique. The faster zonal bands in the torsional-oscillation pattern show strong hemispheric asymmetries and temporal variations in both width and speed. The faster band in the northern hemisphere is located closer to the equator than the band in the southern hemisphere and migrates past the equator when the magnetic activity in the southern hemisphere is reaching maximum. The meridional-flow speed decreases substantially with the increase of magnetic activity, and the flow profile shows two zonal structures in each hemisphere. Themore » residual meridional flow, after subtracting a mean meridional-flow profile, converges toward the activity belts and shows faster and slower bands like the torsional-oscillation pattern. More interestingly, the meridional-flow speed above latitude 30° shows an anti-correlation with the poleward-transporting magnetic flux, slower when the following-polarity flux is transported and faster when the leading-polarity flux is transported. It is expected that this phenomenon slows the process of magnetic cancellation and polarity reversal in high-latitude areas.« less

Correction of bias in belt transect studies of immotile objects

USGS Publications Warehouse

Anderson, D.R.; Pospahala, R.S.

1970-01-01

Unless a correction is made, population estimates derived from a sample of belt transects will be biased if a fraction of, the individuals on the sample transects are not counted. An approach, useful for correcting this bias when sampling immotile populations using transects of a fixed width, is presented. The method assumes that a searcher's ability to find objects near the center of the transect is nearly perfect. The method utilizes a mathematical equation, estimated from the data, to represent the searcher's inability to find all objects at increasing distances from the center of the transect. An example of the analysis of data, formation of the equation, and application is presented using waterfowl nesting data collected in Colorado.

Determining The Plane of The Kuiper Belt with OSSOS

NASA Astrophysics Data System (ADS)

Van Laerhoven, Christa; Kavelaars, J. J.; Volk, Kathryn; Gladman, Brett; Petit, Jean-Marc

2018-04-01

We present the OSSOS-based measurement of the semi-major axes dependent orientation of the Kuiper Belt plane. A Kuiper Belt object's (KBO's) inclination can be broken down into a forced component and a free component. The inclination and longitude of ascending node of the forced inclination define the 'forced plane,' the plane about which the KBO's inclination will precess. Secular theory predicts that this forced plane should depend on semi-major axis. For example, the nu18 secular resonance should create a significant warp in the forced planet near 40.5 au (Chiang and Choi 2008). Not predicted by secular theory is a warp in the distant Kuiper Belt (semi-major axes greater than 50 au) seen by Volk and Malhotra 2016 using KBOs from the Minor Planet Catalog. We investigate what the inclination distribution is for objects beyond Neptune as a function of semi-major axis using the OSSOS characterized sample. Through use of the OSSOS survey simulator we test various underlying orbital distributions and compare how the survey would have observed those populations to the actual observed sample. In particular, we test various widths for the inclination distribution about various local forcing planes for the kernel, stirred, and hot classical Kuiper Belt. We find that the forced plane in matches well with the expected forced plane from secular theory. Through most of the main Kuiper Belt (between the 3:2 and 2:1 resonances), we can reject both the ecliptic plane and the invariable plane as the true forced plane. Only as the expected secularly forced plane approaches the invariable plane does the invariable plane become non-rejectable. In the outer Kuiper Belt we reject the nominal mean-plane measured by Volk and Malhotra, but smaller warps are still allowed by the data.

The behavioral impact of an advertising campaign to promote safety belt use.

PubMed Central

Cope, J G; Moy, S S; Grossnickle, W F

1988-01-01

Safety belt use was observed at one restaurant during McDonald's "Make It Click" promotional campaign. Following baseline, the program was monitored without intervention. During the final 2 weeks of the campaign an incentive strategy was added providing a large soft drink contingent on safety belt use. Safety belt use did not change from baseline levels before the incentive phase. The rate of belt use increased under contingent reward and declined during follow-up. The effects of a verbal prompt could not be assessed because of the almost nonexistent use of the "Make It Click" stickers throughout the study. PMID:3198548

Ripple Belt

NASA Technical Reports Server (NTRS)

2006-01-01

16 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows windblown materials that have collected and been shaped into large ripples in a valley in the Auqakuh Vallis system in northeastern Arabia Terra, Mars.

Location near: 29.1oN, 299.6oW Image width: 2 km (1.2 mi) Illumination from: lower left Season: Northern Winter

Using Phase Space Density Profiles to Investigate the Radiation Belt Seed Population

NASA Astrophysics Data System (ADS)

Boyd, A. J.; Spence, H.; Reeves, G. D.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Turner, D. L.

2013-12-01

It is believed that particles with energies of 100s of keV play a critical role in the acceleration of electrons within the radiation belt. Through wave particle interactions, these so called 'seed electrons' can be accelerated up to energies greater than 1 MeV. Using data from the MagEIS (Magnetic Electron Ion Spectrometer) Instrument onboard the Van Allen Probes we calculate phase space density within the radiation belts over a wide range of mu and K values. These phase space density profiles are combined with those from THEMIS, in order to see how the phase space density evolves over a large range of L*. In this presentation we examine how the seed electron population evolves in both time and L* during acceleration events. Comparing this to the evolution of the higher mu electron population allows us to determine what role the seed electrons played in the acceleration process. Finally, we compare several of these storms to examine the importance of the seed population to the acceleration process.

Investigating the source of near-relativistic and relativistic electrons in Earth's inner radiation belt

DOE PAGES

Turner, Drew Lawson; O'Brien, T. P.; Fennell, J. F.; ...

2017-01-30

Using observations from NASA's Van Allen Probes, we study the role of sudden particle enhancements at low L shells (SPELLS) as a source of inner radiation belt electrons. SPELLS events are characterized by electron intensity enhancements of approximately an order of magnitude or more in less than 1 day at L < 3. During quiet and average geomagnetic conditions, the phase space density radial distributions for fixed first and second adiabatic invariants are peaked at 2 < L < 3 for electrons ranging in energy from ~50 keV to ~1 MeV, indicating that slow inward radial diffusion is not themore » dominant source of inner belt electrons under quiet/average conditions. During SPELLS events, the evolution of electron distributions reveals an enhancement of phase space density that can exceed 3 orders of magnitude in the slot region and continues into the inner radiation belt, which is evidence that these events are an important—and potentially dominant—source of inner belt electrons. Electron fluxes from September 2012 through February 2016 reveal that SPELLS occur frequently (~2.5/month at 200 keV), but the number of observed events decreases exponentially with increasing electron energy for ≥100 keV. After SPELLS events, the slot region reforms due to slow energy-dependent decay over several day time scales, consistent with losses due to interactions with plasmaspheric hiss. Altogether, these results indicate that the peaked phase space density distributions in the inner electron radiation belt result from an “on/off,” geomagnetic-activity-dependent source from higher radial distances.« less

Investigating the source of near-relativistic and relativistic electrons in Earth's inner radiation belt

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

Turner, Drew Lawson; O'Brien, T. P.; Fennell, J. F.

Using observations from NASA's Van Allen Probes, we study the role of sudden particle enhancements at low L shells (SPELLS) as a source of inner radiation belt electrons. SPELLS events are characterized by electron intensity enhancements of approximately an order of magnitude or more in less than 1 day at L < 3. During quiet and average geomagnetic conditions, the phase space density radial distributions for fixed first and second adiabatic invariants are peaked at 2 < L < 3 for electrons ranging in energy from ~50 keV to ~1 MeV, indicating that slow inward radial diffusion is not themore » dominant source of inner belt electrons under quiet/average conditions. During SPELLS events, the evolution of electron distributions reveals an enhancement of phase space density that can exceed 3 orders of magnitude in the slot region and continues into the inner radiation belt, which is evidence that these events are an important—and potentially dominant—source of inner belt electrons. Electron fluxes from September 2012 through February 2016 reveal that SPELLS occur frequently (~2.5/month at 200 keV), but the number of observed events decreases exponentially with increasing electron energy for ≥100 keV. After SPELLS events, the slot region reforms due to slow energy-dependent decay over several day time scales, consistent with losses due to interactions with plasmaspheric hiss. Altogether, these results indicate that the peaked phase space density distributions in the inner electron radiation belt result from an “on/off,” geomagnetic-activity-dependent source from higher radial distances.« less

Development of an arcuate fold-thrust belt as a result of basement configuration: an example from the Rocky Mountain Front Range, Montana

NASA Astrophysics Data System (ADS)

Burberry, C. M.; Cannon, D. L.; Engelder, T.; Cosgrove, J. W.

2010-12-01

The Sawtooth Range forms part of the Montana Disturbed Belt in the Front Ranges of the Rocky Mountains, along strike from the Alberta Syncline in the Canadian Rockies. The belt developed in the footwall to the Lewis Thrust during the Sevier orogeny and is similar in deformation style to the Canadian Foothills, with a series of stacked thrust sheets carrying Palaeozoic carbonates. The Sawtooth Range can be divided into an inner and outer deformed belt, separated by exposed fold structures in the overlying clastic sequence. Structures in the deformed belts plunge into the culmination of the NE-trending Scapegoat-Bannatyne trend, part of the Great Falls Tectonic Zone (GFTZ). Other mapped faults, including the Pendroy fault zone to the north, parallel this trend. A number of mechanisms have been proposed for the development of primary arcs in fold-thrust belts, including linkage of two thrust belts with different strikes, differential transport of segments of the belt, the geometry of the indentor, local plate heterogeneity and pre-existing basement configuration. Arcuate belts may also develop as a result of later bending of an initially straight orogen. In the Swift Dam area, part of the outer belt of the Sawtooth Range, the strike of the belt changes from 165 to 150. This apparent change in strike is accommodated by a sinistral lateral ramp in the Swift Dam Thrust. In addition, this outer belt becomes broader to the north in the Swift Dam region. However, the outer belt becomes extremely narrow in the Teton Canyon region to the south, and the deformation front is characterised by an intercutaneous wedge structure, rather than the trailing-edge imbricate fan seen to the north. A similar imbricate fan structure is seen to the south, in the Sun River Canyon region, corresponding well to the classic model of a deformation belt governed by a dominant thrust sheet, after Boyer & Elliot. The Sawtooth Range can be described as an active-roof duplex in the footwall to the dominant Lewis thrust slab. Analysis of the transport directions of the thrust sheets in the Range implies that the inner arcuate belt is a secondary arc, but that the later, outer arcuate belt formed by divergent transport. This two-stage development model is strongly influenced by the basement configuration. The deformation front of the outer arc is governed by NNW-striking Proterozoic normal fault structures. The entire Sawtooth Range duplex is uplifted over an earlier, NE-trending basement structure (the GFTZ), forming a termination in the Lewis slab. The interaction of these two fault trends allows the development of a linear deformation front in the foreland Jurassic-Cretaceous sequence, but an arcuate belt in the Palaeozoic carbonate sheets. Thus, the width and style of the outer arcuate belt also varies along the strike of the belt.

The effect of increased intra-abdominal pressure on orbital subarachnoid space width and intraocular pressure.

PubMed

Liu, Su-Meng; Wang, Ning-Li; Zuo, Zhen-Tao; Chen, Wei-Wei; Yang, Di-Ya; Li, Zhen; Cao, Yi-Wen

2018-02-01

In accordance with the trans-lamina cribrosa pressure difference theory, decreasing the trans-lamina cribrosa pressure difference can relieve glaucomatous optic neuropathy. Increased intracranial pressure can also reduce optic nerve damage in glaucoma patients, and a safe, effective and noninvasive way to achieve this is by increasing the intra-abdominal pressure. The purpose of this study was to observe the changes in orbital subarachnoid space width and intraocular pressure at elevated intra-abdominal pressure. An inflatable abdominal belt was tied to each of 15 healthy volunteers, aged 22-30 years (12 females and 3 males), at the navel level, without applying pressure to the abdomen, before they laid in the magnetic resonance imaging machine. The baseline orbital subarachnoid space width around the optic nerve was measured by magnetic resonance imaging at 1, 3, 9, and 15 mm behind the globe. The abdominal belt was inflated to increase the pressure to 40 mmHg (1 mmHg = 0.133 kPa), then the orbital subarachnoid space width was measured every 10 minutes for 2 hours. After removal of the pressure, the measurement was repeated 10 and 20 minutes later. In a separate trial, the intraocular pressure was measured for all the subjects at the same time points, before, during and after elevated intra-abdominal pressure. Results showed that the baseline mean orbital subarachnoid space width was 0.88 ± 0.1 mm (range: 0.77-1.05 mm), 0.77 ± 0.11 mm (range: 0.60-0.94 mm), 0.70 ± 0.08 mm (range: 0.62-0.80 mm), and 0.68 ± 0.08 mm (range: 0.57-0.77 mm) at 1, 3, 9, and 15 mm behind the globe, respectively. During the elevated intra-abdominal pressure, the orbital subarachnoid space width increased from the baseline and dilation of the optic nerve sheath was significant at 1, 3 and 9 mm behind the globe. After decompression of the abdominal pressure, the orbital subarachnoid space width normalized and returned to the baseline value. There was no significant difference in the intraocular pressure before, during and after the intra-abdominal pressure elevation. These results verified that the increased intra-abdominal pressure widens the orbital subarachnoid space in this acute trial, but does not alter the intraocular pressure, indicating that intraocular pressure is not affected by rapid increased intra-abdominal pressure. This study was registered in the Chinese Clinical Trial Registry (registration number: ChiCTR-ONRC-14004947).

Conceptual design of novel IP-conveyor-belt Weissenberg-mode data-collection system with multi-readers for macromolecular crystallography. A comparison between Galaxy and Super Galaxy.

PubMed

Sakabe, N; Sakabe, K; Sasaki, K

2004-01-01

Galaxy is a Weissenberg-type high-speed high-resolution and highly accurate fully automatic data-collection system using two cylindrical IP-cassettes each with a radius of 400 mm and a width of 450 mm. It was originally developed for static three-dimensional analysis using X-ray diffraction and was installed on bending-magnet beamline BL6C at the Photon Factory. It was found, however, that Galaxy was also very useful for time-resolved protein crystallography on a time scale of minutes. This has prompted us to design a new IP-conveyor-belt Weissenberg-mode data-collection system called Super Galaxy for time-resolved crystallography with improved time and crystallographic resolution over that achievable with Galaxy. Super Galaxy was designed with a half-cylinder-shaped cassette with a radius of 420 mm and a width of 690 mm. Using 1.0 A incident X-rays, these dimensions correspond to a maximum resolutions of 0.71 A in the vertical direction and 1.58 A in the horizontal. Upper and lower screens can be used to set the frame size of the recorded image. This function is useful not only to reduce the frame exchange time but also to save disk space on the data server. The use of an IP-conveyor-belt and many IP-readers make Super Galaxy well suited for time-resolved, monochromatic X-ray crystallography at a very intense third-generation SR beamline. Here, Galaxy and a conceptual design for Super Galaxy are described, and their suitability for use as data-collection systems for macromolecular time-resolved monochromatic X-ray crystallography are compared.

Wide-field investigation of the Kuiper Belt

NASA Astrophysics Data System (ADS)

Trujillo, Chadwick Aaron

Two wide-field surveys have been conducted for Kuiper Belt Objects (KBOs) and Centaurs using the largest close- packed CCD Mosaic cameras in the world. The first is a wide-field ecliptic survey of 157 square degrees to limiting red magnitude 21.1, responsible for the discovery of 3 KBOs and 1 Centaur. The second is a much deeper survey of 76 square degrees to limiting red magnitude 23.7, which found 86 KBOs. Data were analysed using the same software methods, and a maximum-likelihood simulation was used to debias the observations in a consistent manner. Fundamental quantities describing the Kuiper Belt are derived from these data: size distribution, inclination distribution, radial extent, and total mass. We find that the KBOs follow a differential power law size distribution with index q = 3.8 (+0.3, -0.4 1σ = 68.27% confidence), consistent with the crushed rock size distributions measured in hypervelocity impact experiments. In addition, the debiased inclinations of the Classical KBOs are consistent with a thick Gaussian distribution with half-width 20 (+8, -2 1σ) degrees. The Scattered KBOs are consistent with a Gaussian model with half-width 11 (+6, -3 1σ) degrees, with modal inclination 20 (+9, -4 1σ) degrees. The inclination measurements indicate that the KBOs are in a highly erosive state, with velocity dispersions of 1 to 2 kilometers per second. Strong evidence is presented for a truncation of the Classical KBOs at heliocentric distances beyond 50 AU. The total number and mass of the Scattered KBOs is about 3 times larger than that of the Classical KBOs, with a combined mass from the two populations of about 0.3 Earth masses.

Frequency non-degenerate phase-sensitive optical parametric amplification based on four-wave-mixing in width-modulated silicon waveguides.

PubMed

Wang, Zhaolu; Liu, Hongjun; Sun, Qibing; Huang, Nan; Li, Xuefeng

2014-12-15

A width-modulated silicon waveguide is proposed to realize non-degenerate phase sensitive optical parametric amplification. It is found that the relative phase at the input of the phase sensitive amplifier (PSA) θIn-PSA can be tuned by tailoring the width and length of the second segment of the width-modulated silicon waveguide, which will influence the gain in the parametric amplification process. The maximum gain of PSA is larger by 9 dB compared with the phase insensitive amplifier (PIA) gain, and the gain bandwidth of PSA is larger by 35 nm compared with the gain bandwidth of PIA. Our on-chip PSA can find important potential applications in highly integrated optical circuits for optical chip-to-chip communication and computers.

Reverse Asteroids: Searching for an Effective Tool to Combat Asteroid Belt Misconceptions

NASA Astrophysics Data System (ADS)

Summers, F.; Eisenhamer, B.

2014-12-01

The public 'knows' that asteroid belts are densely packed and dangerous for spaceships to cross. Visuals from "Star Wars" to, unfortunately, the recent "Cosmos" TV series have firmly established this astronomical misconception. However, even scientifically correct graphics, such as the Minor Planet Center's plot of the inner solar system, reinforces that view. Each pixel in the image is more than a million kilometers in width, making an accurate representation of the object density impossible.To address this widespread misconception, we are investigating an educational exercise built around a computer interactive that we call "Reverse Asteroids". In the arcade classic video game, the asteroids came to the player's spaceship. For our reverse implementation, we consider an inquiry-based activity in which the spaceship must go hunting for the asteroids, using a database of real objects in our solar system. Both 3D data visualization and basic statistical analysis play crucial roles in bringing out the true space density within the asteroid belt, and perhaps a reconciliation between imagination and reality. We also emphasize that a partnership of scientists and educators is fundamental to the success of such projects.

Theoretical model of the plasma edge. II. Transport along the open field lines of a magnetic island belt associated with the ionization instability

NASA Astrophysics Data System (ADS)

Rogister, A. L. M.; Hasselberg, G.

1993-12-01

For pt.I, see ibid, p.1799-1816 (1993). To the ionization instability described in Part I correspond odd phi, even br eigenfunctions leading, as for the tearing mode, to a magnetic island belt centred about the rational magnetic surface q = m < qa (q is the safety factor; m is the mode number). Plasma dumping on the target plates, along the island magnetic field lines, releases the neutrals, the ionization of which drives the instability. This self-consistent model of the plasma edge yields the electron temperature on the last closed equilibrium magnetic surface and the particle confinement time, which are compared with the values measured in TEXTOR and other tokamaks; interestingly, the value obtained for τp is very reminiscent of the heuristic energy confinement time expression proposed by Kaye and Goldston(1985). Theory also predicts an equilibrium bifurcation at high power, corresponding to a reduction, and then a collapse, of the island width. The hypothesis that the (L mode) island belt be hooked up to the machine's structure is briefly discussed

Glacial climate driven sedimentation overwhelms tectonics in the battle for control of margin architecture: Southeast Alaska, St. Elias Orogeny

NASA Astrophysics Data System (ADS)

Gulick, S. P.; Jaeger, J. M.; Willems, B.; Powell, R. D.; Lowe, L. A.

2006-12-01

The interplay of tectonic and climatic processes is fundamental to the development of mountain belts and the ensuing patterns of deformation and erosion. Of equal significance is the interaction of tectonic and climatic processes in the development of orogenic sedimentary basins, or in the case of a coastal mountain belt, in the growth of a continental margin. The Chugach-St. Elias Orogeny, which is driven by the collision of the Yakutat microplate with North America in southeast Alaska, has generated the highest coastal relief in the world. The combined forces of tectonic uplift and glacial erosion have resulted in the accumulation of over 5 km of sediment to form the continental shelf and the creation of the Surveyor Fan that is over 2 km thick proximally. High-resolution GI-gun seismic data allow for detailed examination of the margin architecture off the Bering Glacier within the leading edge of the Yakutat block. The deformation and growth of the margin appears to have first undergone a tectonically dominated phase followed more recently by a glacially dominated phase. During the tectonically dominated period a broad anticline-syncline system helped create accommodation space and the margin both shallowed and widened to its current 50 km width. Based on ties with industry well cuttings, the dominance switched sometime between 0.75 and 1.25 Ma to being completely controlled by glacial advance-retreat patterns. The mappable glacial sequences are undeformed by the underlying anticlines and display several notable features: 1) erosional bases that can often be mapped across the entire shelf, terminating at the shelf edge, 2) little evidence for terminal or retreat moraines on the shelf suggesting very rapid and single phase retreat of the glacier, 3) incomplete glacial sequences due to erosion by later advances, and 4) minimal creation of accommodation space. We investigate the cause of the switch to glacial dominance, the mechanisms and causes of the potentially extremely rapid glacial retreats, and the geodynamics of these glacial advances with respect to the development of margin architecture.

Mid-Late Miocene deformation of the northern Kuqa fold-and-thrust belt (southern Chinese Tian Shan): An apatite (U-Th-Sm)/He study

NASA Astrophysics Data System (ADS)

Chang, Jian; Tian, Yuntao; Qiu, Nansheng

2017-01-01

The Kuqa fold-and-thrust belt developed in response to Cenozoic southward shortening between the Chinese Tian Shan and the Tarim Basin. This study aims to constrain the timing of the Late Cenozoic deformation by determining the onset time of enhanced rock cooling using apatite (U-Th-Sm)/He thermochronometry. Eight sedimentary samples were collected from Triassic to Cretaceous strata exposed along a 17 km N-S transect, cross-cutting the northern Kuqa fold-and-thrust belt. Single-grain AHe ages from these samples mostly cluster around 8-16 Ma and are younger than their depositional ages. Older AHe ages show a positive relationship with [eU], a proxy for radiation damage. Modelling of the observed age-eU relationships suggest a phase of enhanced cooling and erosion initiated at Mid-Late Miocene time (10-20 Ma) in the northern Kuqa fold-and-thrust belt. This result is consistent with a coeval abrupt increase of sedimentation rate in the foreland Kuqa depression, south of the study area, indicating a Mid-Late Miocene phase of shortening in the northern Kuqa fold-and-thrust belt.

River meanders and channel size

USGS Publications Warehouse

Williams, G.P.

1986-01-01

This study uses an enlarged data set to (1) compare measured meander geometry to that predicted by the Langbein and Leopold (1966) theory, (2) examine the frequency distribution of the ratio radius of curvature/channel width, and (3) derive 40 empirical equations (31 of which are original) involving meander and channel size features. The data set, part of which comes from publications by other authors, consists of 194 sites from a large variety of physiographic environments in various countries. The Langbein-Leopold sine-generated-curve theory for predicting radius of curvature agrees very well with the field data (78 sites). The ratio radius of curvature/channel width has a modal value in the range of 2 to 3, in accordance with earlier work; about one third of the 79 values is less than 2.0. The 40 empirical relations, most of which include only two variables, involve channel cross-section dimensions (bankfull area, width, and mean depth) and meander features (wavelength, bend length, radius of curvature, and belt width). These relations have very high correlation coefficients, most being in the range of 0.95-0.99. Although channel width traditionally has served as a scale indicator, bankfull cross-sectional area and mean depth also can be used for this purpose. ?? 1986.

A Gaussian measure of quantum phase noise

NASA Technical Reports Server (NTRS)

Schleich, Wolfgang P.; Dowling, Jonathan P.

1992-01-01

We study the width of the semiclassical phase distribution of a quantum state in its dependence on the average number of photons (m) in this state. As a measure of phase noise, we choose the width, delta phi, of the best Gaussian approximation to the dominant peak of this probability curve. For a coherent state, this width decreases with the square root of (m), whereas for a truncated phase state it decreases linearly with increasing (m). For an optimal phase state, delta phi decreases exponentially but so does the area caught underneath the peak: all the probability is stored in the broad wings of the distribution.

Kinematic development of the Tibetan Plateau's northern margin: A traverse across the Qilian Shan-Nan Shan thrust belt

NASA Astrophysics Data System (ADS)

Zuza, A. V.; Levy, D. A.; Wang, Z.; Xiong, X.; Chen, X.

2017-12-01

The active Cenozoic Qilian Shan-Nan Shan thrust belt defines the northern margin of the Tibetan Plateau. The kinematic development of this thrust belt has implications models of plateau growth and Himalayan-Tibetan orogen strain accommodation. We present new field observations and analytical data from a traverse across the 350-km-wide doubly vergent Qilian Shan, which is bound by the south-dipping North Qilian thrust system in the north and the north-dipping range-bounding Qinghai Nanshan-Dulan Shan thrust system in the south. These faults, and several other major thrusts within the thrust-belt interior, disrupt relatively thick Oligocene-Miocene basin deposits. Of note, many of the thrust faults across the width of the Qilian Shan have Quaternary fault scarps, indicating that active deformation is distributed and not only concentrated along the northern frontal faults. By integrating our detailed structural traverse with new geophysical observations and thermochronology data across the northern plateau margin, we construct a kinematic model for the development of the Tibetan Plateau's northern margin. Deformation initiated in the Eocene-Oligocene along the north-dipping Qinghai Nanshan-Dulan Shan and south-dipping Tuolai Nan Shan thrusts, the latter of which then defined the northern boundary of the Tibetan Plateau. This early deformation was focused along preexisting early Paleozoic structures. A 200-km-wide basin formed between these ranges, and from the Miocene to present, new thrust- and strike-slip-fault-bounded ranges developed, including the north-directed North Qilian and the south-directed Tuolai Nan thrusts. Thus, our observations do not support northward propagating thrust-belt expansion. Instead, we envision that the initial thrust-belt development generated a wide Oligocene-Miocene north-plateau basin that was subsequently disintegrated by later Miocene to present thrusting and strike-slip faulting. Ultimately, the Qilian Shan-Nan Shan thrust belt differs from a typical orogenic thrust wedge, and active deformation is distributed across the range.

The Belt voice: Acoustical measurements and esthetic correlates

NASA Astrophysics Data System (ADS)

Bounous, Barry Urban

This dissertation explores the esthetic attributes of the Belt voice through spectral acoustical analysis. The process of understanding the nature and safe practice of Belt is just beginning, whereas the understanding of classical singing is well established. The unique nature of the Belt sound provides difficulties for voice teachers attempting to evaluate the quality and appropriateness of a particular sound or performance. This study attempts to provide answers to the question "does Belt conform to a set of measurable esthetic standards?" In answering this question, this paper expands on a previous study of the esthetic attributes of the classical baritone voice (see "Vocal Beauty", NATS Journal 51,1) which also drew some tentative conclusions about the Belt voice but which had an inadequate sample pool of subjects from which to draw. Further, this study demonstrates that it is possible to scientifically investigate the realm of musical esthetics in the singing voice. It is possible to go beyond the "a trained voice compared to an untrained voice" paradigm when evaluating quantitative vocal parameters and actually investigate what truly beautiful voices do. There are functions of sound energy (measured in dB) transference which may affect the nervous system in predictable ways and which can be measured and associated with esthetics. This study does not show consistency in measurements for absolute beauty (taste) even among belt teachers and researchers but does show some markers with varying degrees of importance which may point to a difference between our cognitive learned response to singing and our emotional, more visceral response to sounds. The markers which are significant in determining vocal beauty are: (1) Vibrancy-Characteristics of vibrato including speed, width, and consistency (low variability). (2) Spectral makeup-Ratio of partial strength above the fundamental to the fundamental. (3) Activity of the voice-The quantity of energy being produced. (4) Consistency of the voice-How low is the variability in the energy patterns of the voice.

Adaptive beam-width control of echolocation sounds by CF-FM bats, Rhinolophus ferrumequinum nippon, during prey-capture flight.

PubMed

Matsuta, Naohiro; Hiryu, Shizuko; Fujioka, Emyo; Yamada, Yasufumi; Riquimaroux, Hiroshi; Watanabe, Yoshiaki

2013-04-01

The echolocation sounds of Japanese CF-FM bats (Rhinolophus ferrumequinum nippon) were measured while the bats pursued a moth (Goniocraspidum pryeri) in a flight chamber. Using a 31-channel microphone array system, we investigated how CF-FM bats adjust pulse direction and beam width according to prey position. During the search and approach phases, the horizontal and vertical beam widths were ±22±5 and ±13±5 deg, respectively. When bats entered the terminal phase approximately 1 m from a moth, distinctive evasive flight by G. pryeri was sometimes observed. Simultaneously, the bats broadened the beam widths of some emissions in both the horizontal (44% of emitted echolocation pulses) and vertical planes (71%). The expanded beam widths were ±36±7 deg (horizontal) and ±30±9 deg (vertical). When moths began evasive flight, the tracking accuracy decreased compared with that during the approach phase. However, in 97% of emissions during the terminal phase, the beam width was wider than the misalignment (the angular difference between the pulse and target directions). These findings indicate that bats actively adjust their beam width to retain the moving target within a spatial echolocation window during the final capture stages.

Coma measurement by use of an alternating phase-shifting mask mark with a specific phase width

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

Qiu Zicheng; Wang Xiangzhao; Yuan Qiongyan

2009-01-10

The correlation between the coma sensitivity of the alternating phase-shifting mask (Alt-PSM) mark and the mark's structure is studied based on the Hopkins theory of partially coherent imaging and positive resist optical lithography (PROLITH) simulation. It is found that an optimized Alt-PSM mark with its phase width being two-thirds its pitch has a higher sensitivity to coma than Alt-PSM marks with the same pitch and the different phase widths. The pitch of the Alt-PSM mark is also optimized by PROLITH simulation, and the structure of p=1.92{lambda}/NA and pw=2p/3 proves to be with the highest sensitivity. The optimized Alt-PSM mark ismore » used as a measurement mark to retrieve coma aberration from the projection optics in lithographic tools. In comparison with an ordinary Alt-PSM mark with its phase width being a half its pitch, the measurement accuracies of Z7 and Z14 apparently increase.« less

Equatorial irregularity belt and its movement during a magnetic storm

NASA Technical Reports Server (NTRS)

Vats, H. O.; Chandra, H.; Deshpande, M. R.; Rastogi, R. G.; Murthy, B. S.; Janve, A. V.; Rai, R. K.; Singh, M.; Gurm, H. S.; Jain, A. R.

1978-01-01

Evidence for an equatorial irregularity belt and its movement during a magnetic storm has been obtained from Faraday rotation measurements at a chain of 140-MHz radio beacons receiving from the ATS-6 satellite. The stations covered a latitude region from the magnetic equator to the 45 deg N dip on the Indian subcontinent. An irregularity belt extending from the magnetic equator to about 27 deg N latitude was observed during the main phase of the magnetic storm of 10 January, 1976.

Chaos on the conveyor belt.

PubMed

Sándor, Bulcsú; Járai-Szabó, Ferenc; Tél, Tamás; Néda, Zoltán

2013-04-01

The dynamics of a spring-block train placed on a moving conveyor belt is investigated both by simple experiments and computer simulations. The first block is connected by a spring to an external static point and, due to the dragging effect of the belt, the blocks undergo complex stick-slip dynamics. A qualitative agreement with the experimental results can be achieved only by taking into account the spatial inhomogeneity of the friction force on the belt's surface, modeled as noise. As a function of the velocity of the conveyor belt and the noise strength, the system exhibits complex, self-organized critical, sometimes chaotic, dynamics and phase transition-like behavior. Noise-induced chaos and intermittency is also observed. Simulations suggest that the maximum complexity of the dynamical states is achieved for a relatively small number of blocks (around five).

Anomalous heat flow belt along the continental margin of Brazil

NASA Astrophysics Data System (ADS)

Hamza, Valiya M.; Vieira, Fabio P.; Silva, Raquel T. A.

2018-01-01

A comprehensive analysis of thermal gradient and heat flow data was carried out for sedimentary basins situated in the continental margin of Brazil (CMB). The results point to the existence of a narrow belt within CMB, where temperature gradients are higher than 30 °C/km and the heat flow is in excess of 70 mW/m2. This anomalous geothermal belt is confined between zones of relatively low to normal heat flow in the adjacent continental and oceanic regions. The width of the belt is somewhat variable, but most of it falls within the range of 100-300 km. The spatial extent is relatively large in the southern (in the basins of Pelotas, Santos and Campos) and northern (in the basins of Potiguar and Ceará) parts, when compared with those in the central parts (in the basins of South Bahia, Sergipe and Alagoas). The characteristics of heat flow anomalies appear to be compatible with those produced by thermal sources at depths in the lower crust. Hence, magma emplacement at the transition zone between lower crust and upper mantle is considered the likely mechanism producing such anomalies. Seismicity within the belt is relatively weak, with focal depths less than 10 km for most of the events. Such observations imply that "tectonic bonding" between continental and oceanic segments, at the transition zone of CMB, is relatively weak. Hence, it is proposed that passive margins like CMB be considered as constituting a type of plate boundary that is aseismic at sub-crustal levels, but allows for escape of significant amounts of earth's internal heat at shallow depths.

Lunar Sodium and Potassium Exosphere in May 2014

NASA Astrophysics Data System (ADS)

Oliversen, R. J.; Kuruppuaratchi, D. C. P.; Mierkiewicz, E. J.; Derr, N. J.; Rosborough, S.; Gallant, M. A.; Roesler, F. L.

2015-12-01

We apply high resolution spectroscopy to investigate the lunar exosphere by measuring sodium and potassium spectral line profiles to determine the variations in exospheric effective temperatures and velocities. Observations were made at the National Solar Observatory McMath-Pierce Telescope during May 2014. Data were collected over several nights, centered on full moon (May 14) and covering a waxing phase angle of 67° to a waning phase angle of 75°. We used a dual-etalon Fabry-Perot spectrometer with a resolving power of 184,000 (1.63 km s-1) to measure the line widths and radial velocity shifts of the sodium D2 (5889.951 Å) and potassium D1 (7698.965 Å) emission lines. The field of view was 3 arcmin (~330 km) and positioned at several locations, each centered at 1.5 arcmin (~165 km) off the East and West sunlit limbs. The deconvolved line widths indicate significant differences between the sodium and potassium temperatures. The sodium line widths were mostly symmetric as a function of phase for both the waxing and waning phases. At phase angles > 40º (outside of the magnetotail) the full width half maximum (FWHM) line widths are 1.5 - 2.0 km s-1 or ~1500 K for FWHM = 1.75 km s-1. Inside the magnetotail (phase angle < 40º) and near full moon (phase angle ~6°), the FWHM increased to ~4 km s-1. The implied line width temperature is 8000 K, although some of the observed line width may be due to a dispersion in velocities from many contribution along the extended sodium tail. Unlike sodium, the potassium line widths are wider by 50% during the waxing phase compared to the waning phase at phases > 40º. The potassium temperatures pre-magnetotail passage are ~1000 K while the temperatures post-magnetotail passage are ~2000K. At phase angles < 40º, the potassium intensities decreased dramatically; on consecutive days, when the phase angle changed from 44º to 31º to 20º, the relative intensities dropped by 1.0:0.6:0.15. The potassium intensity in the East and West equatorial regions (latitude < 10º) were similar; however, the potassium intensity was brightest off the limb near Aristarchus (latitude ~24º), which was the crater we observed nearest the KREEP region. This work was partially supported by the NASA Planetary Astronomy programs, NNX11AE38G and NNX13AL30G.

Electron radiation belt dynamics during magnetic storms and in quiet time

NASA Astrophysics Data System (ADS)

Lazutin, Leonid; Dmitriev, Aleksey; Suvorova, Alla

2018-03-01

The paper discusses the dynamics of the outer electron belt, adiabatic and nonadiabatic mechanisms of replenishment and losses of energetic electrons. Under undisturbed conditions, the outer electron belt gradually empties: in the inner magnetosphere due to electron precipitation in the atmosphere and in the quasi-trapping region due to losses at the magnetopause because drift shells of electrons are not closed there. The latter process does not occur in normal years due to the masking replenishment by freshly accelerated particles, but in years of extremely low activity, it leads to a significant decrease in the electron population of the belt. During the magnetic storm main phase, the first reason for the decrease in the electron flux intensity is the adiabatic cooling associated with conservation of adiabatic invariants and complemented by precipitation of electrons into the atmosphere and their dropout at the magnetopause. Electron flux increases involve E×B electron injection by the induction electric field of substorm activation and by the large-scale solar wind electric field, with pitch energy diffusion along with adiabatic heating in the recovery phase. The rate of electron flux recovery after a storm is determined by the ratio of nonadiabatic increases and losses; hence the electron flux represents a continuous series from low to very high values. The combination of these processes determines the individual character of radiation belt development during each magnetic storm and the behavior of the belt in the quiet time.

Tectonics and kinematics of a foreland folded belt influenced by salt, arctic Canada

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

Harrison, J.C.

1996-12-31

The Ordovician (upper Arenig-Llanvirn) Bay Fiord Formation is one of three widespread evaporite units known to have profoundly influenced the style of contractional tectonics within the Innuitian orogen of Arctic Canada. In the western Arctic Islands, the salt-bearing Bay Fiord Formation has accommodated buckling and mostly subsurface thrusting in the west-trending Parry Islands foldbelt. A characteristic feature of this belt is a stratigraphic succession more than 10 km thick featuring three rigid and widespread sedimentary layers and two intervening ductile layers (lower salt and upper shale). The ductile strata have migrated to anticlinal welts during buckling. Other features of themore » foldbelt include (1) an extreme length of individual upright folds (up to 330 km), (2) extreme foldbelt width (up to 11%), (5) a shallow dipping salt decollement system (0.1{degrees}-0.6{degrees}) that has also been folded in the hinterland and later extended, and (6) a complete absence of halokinetic piercing diapirs. The progression from simple thrust-fold structure on the foldbelt periphery to complex in the interior provides a viable kinematic model for this and other contractional salt provinces. One feature of this model is a single massive triangle zone structure (passive roof duplex) that may envelop the entire 200-km width of the foldbelt and underlie an area exceeding 52,000 km{sup 2}.« less

Few-Mode Whispering-Gallery-Mode Resonators

NASA Technical Reports Server (NTRS)

Savchenkov, Anatoliy; Strekalov, Dmitry; Matsko, Andrey; Iltchenko, Vladimir; Maleki, Lute

2006-01-01

Whispering-gallery-mode (WGM) optical resonators of a type now under development are designed to support few well-defined waveguide modes. In the simplest case, a resonator of this type would support one equatorial family of WGMs; in a more complex case, such a resonator would be made to support two, three, or some other specified finite number of modes. Such a resonator can be made of almost any transparent material commonly used in optics. The nature of the supported modes does not depend on which material is used, and the geometrical dispersion of this resonator is much smaller than that of a typical prior WGM resonator. Moreover, in principle, many such resonators could be fabricated as integral parts of a single chip. Basically, a resonator of this type consists of a rod, made of a suitable transparent material, from which protrudes a thin circumferential belt of the same material. The belt is integral with the rest of the rod (see figure) and acts as a circumferential waveguide. If the depth (d) and width (w) of the belt are made appropriately small, then the belt acts as though it were the core of a single-mode optical fiber: the belt and its adjacent supporting rod material support a single, circumferentially propagating mode or family of modes. It has been shown theoretically that the fiber-optic-like behavior of the belton- rod resonator structure can be summarized, in part, by the difference, Dn, between (1) an effective index of refraction of an imaginary fiber core and (2) the index of refraction (n) of the transparent rod/belt material. It has also been shown theoretically that for a given required value of Dn, the required depth of the belt can be estimated as d R Dn, where R is the radius of the rod. It must be emphasized that this estimated depth is independent of n and, hence, is independent of the choice of rod material. As in the cases of prior WGM resonators, input/output optical coupling involves utilization of evanescent fields. In the present case, there are two evanescent fields: one at the belt/air interface and one in the boundary region between the belt and the rest of the rod.

Effect of smectic A temperature width on the soft mode in ferroelectric liquid crystals

NASA Astrophysics Data System (ADS)

Choudhary, A.; Kaur, S.; Prakash, J.; Sreenivas, K.; Bawa, S. S.; Biradar, A. M.

2008-08-01

The behavior of soft mode range with respect to the temperature width of smectic A (Sm A) phase has been studied in four different ferroelectric liquid crystal (FLC) materials in the frequency range 10Hz-10MHz. The studies have been carried out in a planarly well aligned cells at different temperatures and different bias fields in Sm C* and Sm A phases. Dielectric studies of these FLCs near Sm C*-Sm A phase transition show that the temperature range of soft mode relaxation frequency phenomenon varies with the temperature width of Sm A phase. The dependence of tilt angle on temperature shows the nature of the order of transition at Sm C*-Sm A phase. The coupling between order parameters of Sm C* and Sm A phase influences the soft mode and phase transition in Sm C* and Sm A phases.

Transposition of a Process-Based Model, Flumy: from Meandering Fluvial Systems to Channelized Turbidite Systems

NASA Astrophysics Data System (ADS)

Lemay, M.; Cojan, I.; Rivoirard, J.; Grimaud, J. L.; Ors, F.

2017-12-01

Channelized turbidite systems are among the most important hydrocarbon reservoirs. Yet building realistic turbidite reservoir models is still a challenge. Flumy has been firstly developed to simulate the long-term evolution of aggrading meandering fluvial systems in order to build facies reservoir models. In this study, Flumy has been transposed to channelized turbidite systems. The channel migration linear model of Imran et al. (1999) dedicated to subaqueous flows has been implemented. The whole model has been calibrated taking into account the differences on channel morphology, avulsion frequency, and aggradation and migration rates. This calibration and the comparison of the model to natural systems rely on: i) the channel planform morphology characterized by the meander wavelength, amplitude, and sinuosity; ii) the channel trajectory and the resulting stratigraphic architecture described using Jobe et al. (2016) indexes. Flumy succeeds in reproducing turbidite channel planform morphology as shown by the mean sinuosity of 1.7, the wavelength to width and amplitude to width ratios around 4 and 1 respectively. First-order meander architecture, characterized by the ratios meander belt width versus channel width, meander belt thickness versus channel depth, and the deduced stratigraphic mobility number (the ratio between lateral versus vertical channel displacements), is also well reproduced: 2.5, 3.8, and 0.6 respectively. Both lateral and downstream channel normalized migrations are around 3.5 times lower than in fluvial systems. All these values are absolutely coherent with the observations. In the other hand, the channel trajectory observed on seismic cross sections (hockey stick geometry) is not fully reproduced: the local stratigraphic mobility number is divided upward by 3 whereas up to 10 is expected. This behavior is generally explained in the literature by an increasing aggradation rate through time and/or flow stripping at outer bend that decreases lateral migration rate (Peakall et al., 2000). These processes are not currently simulated in Flumy, and need to be implemented. This study shows that Flumy model reproduces quite well the first order characteristics observed in the nature and can be used to simulate channelized turbidite reservoirs.

Venus tectonics: initial analysis from magellan.

PubMed

Solomon, S C; Head, J W; Kaula, W M; McKenzie, D; Parsons, B; Phillips, R J; Schubert, G; Talwani, M

1991-04-12

Radar imaging and altimetry data from the Magellan mission have revealed a diversity of deformational features at a variety of spatial scales on the Venus surface. The plains record a superposition of different episodes of deformation and volcanism; strain is both areally distributed and concentrated into zones of extension and shortening. The common coherence of strain patterns over hundreds of kilometers implies that many features in the plains reflect a crustal response to mantle dynamic processes. Ridge belts and mountain belts represent successive degrees of lithospheric shortening and crustal thickening; the mountain belts also show widespread evidence for extension and collapse both during and following crustal compression. Venus displays two geometrical patterns of concentrated lithospheric extension: quasi-circular coronae and broad rises with linear rift zones; both are sites of significant volcanism. No long, large-offset strike-slip faults have been observed, although limited local horizontal shear is accommodated across many zones of crustal shortening. In general, tectonic features on Venus are unlike those in Earth's oceanic regions in that strain typically is distributed across broad zones that are one to a few hundred kilometers wide, and separated by stronger and less deformed blocks hundreds of kilometers in width, as in actively deforming continental regions on Earth.

Mineral parageneses, regional architecture, and tectonic evolution of Franciscan metagraywackes, Cape Mendocino-Garberville-Covelo 30' x 60' quadrangles, northwest California

USGS Publications Warehouse

Ernst, W.G.; McLaughlin, Robert J.

2012-01-01

The Franciscan Complex is a classic subduction-zone assemblage. In northwest California, it comprises a stack of west vergent thrust sheets: westernmost Eastern Belt outliers; Central Belt mélange; Coastal Belt Yager terrane; Coastal Belt Coastal terrane; Coastal Belt King Range/False Cape terranes. We collected samples and determined P-T conditions of recrystallization for 88 medium-fine-grained metasandstones to assess their subduction-exhumation histories and assembly of the host allochthons. Feebly recrystallized Yager, Coastal, and King Range strata retain clear detrital features. Scattered neoblastic prehnite occurs in several Coastal terrane metasandstones; traces of possible pumpellyite are present in three Yager metaclastic rocks. Pumpellyite ± lawsonite ± aragonite-bearing Central Belt metasandstones are moderately deformed and reconstituted. Intensely contorted, thoroughly recrystallized Eastern Belt affinity quartzose metagraywackes contain lawsonite + jadeitic pyroxene ± aragonite ± glaucophane. We microprobed neoblastic phases in 23 rocks, documenting mineral parageneses that constrain the tectonic accretion and metamorphic P-T evolution of these sheets. Quasi-stable mineral assemblages typify Eastern Belt metasandstones, but mm-sized domains in the Central and Coastal belt rocks failed to achieve chemical equilibrium. Eastern Belt slabs rose from subduction depths approaching 25–30 km, whereas structurally lower Central Belt mélanges returned from ∼15–18 km. Coastal Belt assemblages suggest burial depths less than 5–8 km. Eastern and Central belt allochthons sequentially decoupled from the downgoing oceanic lithosphere and ascended into the accretionary margin; K-feldspar-rich Coastal Belt rocks were stranded along the continental edge without undergoing appreciable subduction, probably during Paleogene unroofing of the older, deeply subducted units of the Franciscan Complex in east-vergent crustal wedges.

49 CFR 585.24 - Reporting requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase-In Reporting Requirements § 585.24 Reporting requirements. (a) Advanced credit phase-in... paragraph (c) of this section and in § 585.2 of this part. (b) Phase-in reporting requirements. Within 60...

49 CFR 585.24 - Reporting requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase-In Reporting Requirements § 585.24 Reporting requirements. (a) Advanced credit phase-in... paragraph (c) of this section and in § 585.2 of this part. (b) Phase-in reporting requirements. Within 60...

[Altitude-belt zonality of wood vegetation within mountainous regions of the Sayan Mountains: a model of ecological second-order phase transitions ].

PubMed

Sukhovol'skiĭ, V G; Ovchinnikova, T M; Baboĭ, S D

2014-01-01

As a description of altitude-belt zonality of wood vegetation, a model of ecological second-order transitions is proposed. Objects of the study have been chosen to be forest cenoses of the northern slope of Kulumyss Ridge (the Sayan Mauntains), while the results are comprised by the altitude profiles of wood vegetation. An ecological phase transition can be considered as the transition of cenoses at different altitudes from the state of presence of certain tree species within the studied territory to the state of their absence. By analogy with the physical model of second-order, phase transitions the order parameter is introduced (i.e., the area portion occupied by a single tree species at the certain altitude) as well as the control variable (i.e., the altitude of the wood vegetation belt). As the formal relation between them, an analog of the Landau's equation for phase transitions in physical systems is obtained. It is shown that the model is in a good accordance with the empirical data. Thus, the model can be used for estimation of upper and lower boundaries of altitude belts for individual tree species (like birch, aspen, Siberian fir, Siberian pine) as well as the breadth of their ecological niches with regard to altitude. The model includes also the parameters that describe numerically the interactions between different species of wood vegetation. The approach versatility allows to simplify description and modeling of wood vegetation altitude zonality, and enables assessment of vegetation cenoses response to climatic changes.

The "normal" elongation of river basins

NASA Astrophysics Data System (ADS)

Castelltort, Sebastien

2013-04-01

The spacing between major transverse rivers at the front of Earth's linear mountain belts consistently scales with about half of the mountain half-width [1], despite strong differences in climate and rock uplift rates. Like other empirical measures describing drainage network geometry this result seems to indicate that the form of river basins, among other properties of landscapes, is invariant. Paradoxically, in many current landscape evolution models, the patterns of drainage network organization, as seen for example in drainage density and channel spacing, seem to depend on both climate [2-4] and tectonics [5]. Hovius' observation [1] is one of several unexplained "laws" in geomorphology that still sheds mystery on how water, and rivers in particular, shape the Earth's landscapes. This narrow range of drainage network shapes found in the Earth's orogens is classicaly regarded as an optimal catchment geometry that embodies a "most probable state" in the uplift-erosion system of a linear mountain belt. River basins currently having an aspect away from this geometry are usually considered unstable and expected to re-equilibrate over geological time-scales. Here I show that the Length/Width~2 aspect ratio of drainage basins in linear mountain belts is the natural expectation of sampling a uniform or normal distribution of basin shapes, and bears no information on the geomorphic processes responsible for landscape development. This finding also applies to Hack's [6] law of river basins areas and lengths, a close parent of Hovius' law. [1]Hovius, N. Basin Res. 8, 29-44 (1996) [2]Simpson, G. & Schlunegger, F. J. Geophys. Res. 108, 2300 (2003) [3]Tucker, G. & Bras, R. Water Resour. Res. 34, 2751-2764 (1998) [4]Tucker, G. & Slingerland, R. Water Resour. Res. 33, 2031-2047 (1997) [5]Tucker, G. E. & Whipple, K. X. J. Geophys. Res. 107, 1-1 (2002) [6]Hack, J. US Geol. Surv. Prof. Pap. 294-B (1957)

Diffusion by one wave and by many waves

NASA Astrophysics Data System (ADS)

Albert, J. M.

2010-03-01

Radiation belt electrons and chorus waves are an outstanding instance of the important role cyclotron resonant wave-particle interactions play in the magnetosphere. Chorus waves are particularly complex, often occurring with large amplitude, narrowband but drifting frequency and fine structure. Nevertheless, modeling their effect on radiation belt electrons with bounce-averaged broadband quasi-linear theory seems to yield reasonable results. It is known that coherent interactions with monochromatic waves can cause particle diffusion, as well as radically different phase bunching and phase trapping behavior. Here the two formulations of diffusion, while conceptually different, are shown to give identical diffusion coefficients, in the narrowband limit of quasi-linear theory. It is further shown that suitably averaging the monochromatic diffusion coefficients over frequency and wave normal angle parameters reproduces the full broadband quasi-linear results. This may account for the rather surprising success of quasi-linear theory in modeling radiation belt electrons undergoing diffusion by chorus waves.

Proceedings of the ATB Model Users Group Conference Held in Phoenix, Arizona on 8-9 February 1996.

DTIC Science & Technology

1996-02-09

8217 0.3 Cards Harness Belt Geomietry iEVRNMNTIHamess F.8 Cards Airbag Geometry EVRNMNT/ Airbags D.4 Cards Spring/Dampers EVIRNIVNTISpring-Dampers 0.8 Cards...Conference Units of Measurement o Specify Length, Force, & Time Units o English - Inches, Pounds, Seconds - Most commonly used - Field width problems ...Proceedings of the 1996 ATB Model Users’ Group Conference 22 Airbags Reaction Panels "Contacting Body DeploymentPrmy Point Reaction Panel Spring-Dampers

What happens along the flank and corner of a continental indenter? Insights from the easternmost Himalayan orogen and constraints on the models of the India-Asia collision

NASA Astrophysics Data System (ADS)

Haproff, P. J.; Yin, A.; Zuza, A. V.

2017-12-01

Investigations of continental collisions often focus on thrust belts oriented perpendicular to the plate-convergence direction and exclude belts that bound the flanks of a continental indenter despite being crucial to understanding the collisional process. Research of the Himalayan orogen, for example, has mostly centered on the east-trending thrust belt between the eastern and western syntaxes, resulting in inadequate examination of the north-trending Indo-Burma Ranges located along the eastern margin of India. To better understand the development of the entire Himalayan orogenic system, we conducted field mapping across the Northern Indo-Burma Range (NIBR), situated at the intersection of the eastern Himalaya and Indo-Burma Ranges. Our research shows that major lithologic units and thrust faults of the Himalaya extend to the NIBR, suggesting a shared geologic evolution. The structural framework of the NIBR consists of a southwest-directed thrust belt cored by a hinterland-dipping duplex, like the Himalaya. However, the Northern Indo-Burma orogen is distinct based on (1) the absence of the Tethyan Himalayan Sequence and southern Gangdese batholith, (2) the absence of the South Tibetan detachment, (3) crustal shortening greater than 80%, (4) an incredibly narrow orogen width of 7-33 km, (5) exposure of an ophiolitic mélange complex as a klippe, (6) and right-slip shear along the active range-bounding thrust fault. Furthermore, lithospheric deformation along the flank and northeast corner of India is characterized by right-slip transpression partitioned between the thrust belt and right-slip faults. Such a regime is interpreted to accommodate both contraction and clockwise rotation of Tibetan lithosphere around India, consistent with existing continuum deformation and rotation models.

Improving the driving practices of pizza deliverers: Response generalization and moderating effects of driving history

PubMed Central

Ludwig, Timothy D.; Geller, E. Scott

1991-01-01

A practical intervention program, targeting the safety belt use of pizza deliverers at two stores, increased significantly the use of both safety belts (143% above baseline) and turn signals (25% above baseline). Control subjects (i.e., pizza deliverers at a third no-intervention store and patrons driving to the pizza stores) showed no changes in belt or turn signal use over the course of 7-month study. The intervention program was staggered across two pizza stores and consisted of a group meeting wherein employees discussed the value of safety belts, received feedback regarding their low safety belt use, offered suggestions for increasing their belt use, and made a personal commitment to buckle up by signing buckle-up promise cards. Subsequently, employee-designed buckle-up reminder signs were placed in the pizza stores. By linking license plate numbers to individual driving records, we examined certain aspects of driving history as moderators of pre- and postintervention belt use. Although baseline belt use was significantly lower for drivers with one or more driving demerits or accidents in the previous 5 years, after the intervention these risk groups increased their belt use significantly and at the same rate as drivers with no demerits or accidents. Whereas baseline belt use was similar for younger (under 25) and older (25 or older) drivers, younger drivers were markedly more influenced by the intervention than were older drivers. Individual variation in belt use during baseline, intervention, and follow-up phases indicated that some drivers require more effective and costly intervention programs to motivate their safe driving practices. PMID:16795743

Diffusive vs. impulsive energetic electron transport during radiation belt storms

NASA Astrophysics Data System (ADS)

Vassiliadis, D.; Koepke, M.; Tornquist, M.

2008-12-01

Earth's electron radiation belts are continually replenished by inward particle transport (as well as other, local acceleration processes) taking place during radiation belt storms. For some storms the radial transport is primarily diffusive while for others it is impulsive, or characterized by injections. To distinguish between these types of inward transport, we first use a dynamic model of the phase-space density as measured by POLAR/HIST and expressed in terms of adiabatic invariants [Green and Kivelson, 2004]. In a review of storms from 1997 to 2004 the coefficients of the model are peaked at characteristic temporal and phase- space (mu, k, L*) scales during specific storms. The transport is quantified in terms of those invariants which are violated and identified with peaks of the electron distribution in invariant space. Second, we run guiding- center simulations in wave fields fitted to in situ measurements complemented at low and high L by ground ULF pulsations. The modes of response identified in earlier studies from SAMPEX and POLAR electron flux measurements are now associated with primarily diffusive transport in the central range of the outer belt, L=4-8, and primarily impulsive transport near the plasmapause boundary, L=3-4.

Tectonic controls on the morphodynamics of the Brahmaputra River system in the upper Assam valley, India

NASA Astrophysics Data System (ADS)

Lahiri, Siddhartha K.; Sinha, Rajiv

2012-10-01

The Brahmaputra is one of the largest tropical rivers of the world and is located in an area of high structural instability as evidenced from the presence of a large number of earthquakes in the Himalayan catchment through which it flows. Syntectonic evidence of changes in the morphodynamics is difficult to identify for the large rivers. Nevertheless, we note that the Brahmaputra River has become astonishingly large in planform in a historical timescale. Reconstruction of planform changes over a period of 90 years in the upper reaches of the Assam valley shows that the 240-km-long channel belt is widening all along its course in the region. From the average width of 9.74 km in 1915, the channel belt has widened to the average width of 14.03 km in 2005 (44% widening), and in certain reaches the average widening is as high as 250%. However, the bank line shift is not symmetric along both banks. Further, the planform characteristics of the Brahmaputra River reveal significant spatial and temporal variability from upstream to downstream reaches, and we attribute this variability to tectonogeomorphic zonation of the river based on subsurface configuration and channel slope. Further, the tributaries joining the northern and southern banks of the Brahmaputra differ remarkably in terms of river dynamics, and this is attributed to the differences in tectonic regimes of the Himalaya in the north and the Naga Patkai hills in the south.

Anomalous deepening of a belt of intraslab earthquakes in the Pacific slab crust under Kanto, central Japan: Possible anomalous thermal shielding, dehydration reactions, and seismicity caused by shallower cold slab material

USGS Publications Warehouse

Hasegawa, A.; Nakajima, J.; Kita, S.; Okada, T.; Matsuzawa, T.; Kirby, S.H.

2007-01-01

A belt of intraslab seismicity in the Pacific slab crust parallel to iso-depth contours of the plate interface has been found beneath Hokkaido and Tohoku. Hypocenter relocations have shown that this seismic belt does not run parallel to but obliquely to the iso-depth contours beneath Kanto, deepening toward the north from ???100 km to ???140 km depth. The depth limit of the contact zone with the overlying Philippine Sea slab is located close to and parallel to this obliquely oriented seismic belt, suggesting that the deepening of the seismic belt there is caused by the contact with the overlying slab. The contact with this cold slab hinders the heating of the Pacific slab crust by hot mantle wedge, which would cause delay of eclogite-forming phase transformations and hence deepening of the seismic belt there. The depth limit of the subducting low-velocity crust also deepens toward the north, supporting this idea. Copyright 2007 by the American Geophysical Union.

Kinematic evolution of a regional-scale gravity-driven deepwater fold-and-thrust belt: The Lamu Basin case-history (East Africa)

NASA Astrophysics Data System (ADS)

Cruciani, F.; Barchi, M. R.; Koyi, H. A.; Porreca, M.

2017-08-01

The deepwater fold-and-thrust belts (DWFTBs) are geological structures recently explored thanks to advances in offshore seismic imaging by oil industry. In this study we present a kinematic analysis based on three balanced cross-sections of depth-converted, 2-D seismic profiles along the offshore Lamu Basin (East African passive margin). This margin is characterized by a regional-scale DWFTB (> 450 km long), which is the product of gravity-driven contraction on the shelf that exhibits complex structural styles and differing amount of shortening along strike. Net shortening is up to 48 km in the northern wider part of the fold-and-thrust belt (≈ 180 km), diminishing to < 15 km toward the south, where the belt is markedly narrower (≈ 50 km). The three balanced profiles show a shortening percentage around 20% (comparable with the maximum values documented in other gravity-driven DWFTBs), with a significant variability along dip: higher values are achieved in the outer (i.e. down-dip) portion of the system, dominated by basinward-verging, imbricate thrust sheets. Fold wavelength increases landward, where doubly-verging structures and symmetric detachment folds accommodate a lower amount of shortening. Similar to other cases, a linear and systematic relationship between sedimentary thickness and fold wavelength is observed. Reconstruction of the rate of shortening through time within a fold-and-thrust belt shows that after an early phase of slow activation (Late Cretaceous), > 95% of net shortening was produced in < 10 Myr (during Paleocene). During this acme phase, which followed a period of high sedimentation rate, thrusts were largely synchronous and the shortening rate reached a maximum value of 5 mm/yr. The kinematic evolution reconstructed in this study suggests that the structural evolution of gravity-driven fold-and-thrust belts differs from the accretionary wedges and the collisional fold-and-thrust belts, where thrusts propagate in-sequence and shortening is uniformly accommodated along dip.

Tectonic evolution of part of the Southern Metamorphic Belt of the Armorican Massif including the Ile de Groix

NASA Astrophysics Data System (ADS)

Richards, Lawrence Edward

The Southern Metamorphic Belt (SMB) of the Armorican Massifextends 400km along the south coast of Brittany and into Vendee. It is separated from the Central Armorican Domain by a major, late-Hercynian shear belt, known as the South Armorican Shear Zone. In the area studied, belts of metasedimentary and metavolcanic schist of uncertain age are separated by belts of granitic gneiss; areas of migmatite and Hercynian granite plutons cross-cut these belts. Three distinctive lithologic assemblages have been identified in the schist belts, characteristic of different depositional environments: the Le Pouldu Group, Kerleven and Gouesnach formations probably originated as abyssal black shales deposited on oceanic crust; the St. Laurent Formation and Melgven Schists probably formed as distal greywacke deposits on a deep continental shelf; the Nerly and Beg-Meil formations probably formed in a proximal marine or fluviatile environment. These disparate assemblages were tectonically juxtaposed by overthrusting (obduction) before an amphibolite facies metamorphism and deformation during the Cadomian Orogeny. The Moelan Gneiss, a Lower Ordovician alkali-granite intrusion, postdates M1/D1 and probably formed in a rifting environment at the onset of ocean-floor spreading along an axis south of the present Armorican Massif. The famous blueschists of the Ile de Groix probably formed in a subduction zone on the south side of the ocean and were obducted onto the passive southern margin of the Armorican Massif following closure of the ocean and continental collision. A second phase of regional deformation, producing a cataclastic foliation in the Moelan Gneiss, probably resulted from the collision. Large-scale overthrusting of the southern continent onto the Armorican Massif took place, causing metamorphism with partial melting at depth generating migmatites. A third phase of pervasive deformation may correlate with oroclinal bending of the Ibero-Armorican Arc during the Hercynian Orogeny.

Photometric geodesy of main-belt asteroids. IV - An updated analysis of lightcurves for poles, periods, and shapes

NASA Technical Reports Server (NTRS)

Drummond, J. D.; Weidenschilling, S. J.; Chapman, C. R.; Davis, D. R.

1991-01-01

The Drummond et al. (1988) analysis of main-belt asteroids is presently extended, using three independent methods to derive poles, periods, phase functions, and triaxial ellipsoid shapes from lightcurve maxima and minima. This group of 26 asteroids is also reinvestigated with a view to the distributions of triaxial shapes and obliquity distributions. Poles weakly tend to avoid asteroid orbital planes; a rough-smooth dichotomization appears to be justified by the persistence of two solar phase angle-amplitude relations. Seven of the objects may be Jacobi ellipsoids if axial ratios are slightly exaggerated by a systematic effect of the analytical method employed.

Facile synthesis, phase transition, optical switching and oxidation resistance properties of belt-like VO{sub 2}(A) and VO{sub 2}(M) with a rectangular cross section

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

Zhang, Yifu; Huang, Yanfen; Zhang, Juecheng

2012-08-15

Highlights: ► Belt-like VO{sub 2}(A) with a rectangular cross section was synthesized. ► The formation mechanism of belt-like VO{sub 2}(A) was proposed. ► Belt-like VO{sub 2}(M) was prepared by the irreversible transformation of VO{sub 2}(A). ► VO{sub 2}(A) and VO{sub 2}(M) can be used as the optical switching materials. ► VO{sub 2}(A) and VO{sub 2}(M) have good oxidation resistance below 400 °C in air. -- Abstract: Belt-like VO{sub 2}(A) with a rectangular cross section (VA-RCS) was successfully synthesized using V{sub 2}O{sub 5}, H{sub 2}C{sub 2}O{sub 4}·2H{sub 2}O and H{sub 2}O as the starting materials by a facile hydrothermal approach. Somemore » synthetic parameters, such as, the reaction time, reaction temperature and concentration of H{sub 2}C{sub 2}O{sub 4}·2H{sub 2}O, were systematically investigated to control the fabrication of belt-like VA-RCS. The formation mechanism of belt-like VA-RCS was proposed. Subsequently, belt-like VO{sub 2}(M) with a rectangular cross section (VM-RCS) was prepared by the irreversible transformation of VA-RCS at 700 °C for 2 h under the inert atmosphere. The phase transition temperature (T{sub c}) of VA-RCS and VM-RCS was evaluated by DSC test. The optical switching properties of VA-RCS and VM-RCS were studied by the variable-temperature infrared spectra, and it was found that the as-obtained VA-RCS and VM-RCS could be used as the optical switching materials. Furthermore, the oxidation resistance properties of VA-RCS and VM-RCS were investigated by TGA, indicating that they have good thermal stability and oxidation resistance below 400 °C in air.« less

Spectrometry of Jupiter at selected locations on the disk during the 1979 apparition

NASA Technical Reports Server (NTRS)

Cochran, A. L.; Trafton, L. M.; Cochran, W. D.; Barker, E. S.

1981-01-01

Jupiter's reflectivity was measured as a function of wavelength between 3000 and 10,500 Angstrom for two nights during the 1979 apparition. The spectra obtained were used to calibrate the wavelength response of Voyager images and to establish differences from previous apparitions. The observations were taken in the prominent belts and zones and both polar caps along the central meridian using a slit of dimensions 2.33 x 2.5 sq arcsec. The equivalent widths of the 6190 and 7270 Angstrom CH4 bands were measured; compared to the 1976 apparition, there was significantly less CH4 absorption in the north tropical zone. Such equivalent-width decreases are said to result from either a reduction in particle albedo or a decrease in the scattering mean free path owing to a greater concentration of aerosol particles in the NTrZ.

Statistical analysis of corn yields responding to climate variability at various spatio-temporal resolutions

NASA Astrophysics Data System (ADS)

Jiang, H.; Lin, T.

2017-12-01

Rain-fed corn production systems are subject to sub-seasonal variations of precipitation and temperature during the growing season. As each growth phase has varied inherent physiological process, plants necessitate different optimal environmental conditions during each phase. However, this temporal heterogeneity towards climate variability alongside the lifecycle of crops is often simplified and fixed as constant responses in large scale statistical modeling analysis. To capture the time-variant growing requirements in large scale statistical analysis, we develop and compare statistical models at various spatial and temporal resolutions to quantify the relationship between corn yield and weather factors for 12 corn belt states from 1981 to 2016. The study compares three spatial resolutions (county, agricultural district, and state scale) and three temporal resolutions (crop growth phase, monthly, and growing season) to characterize the effects of spatial and temporal variability. Our results show that the agricultural district model together with growth phase resolution can explain 52% variations of corn yield caused by temperature and precipitation variability. It provides a practical model structure balancing the overfitting problem in county specific model and weak explanation power in state specific model. In US corn belt, precipitation has positive impact on corn yield in growing season except for vegetative stage while extreme heat attains highest sensitivity from silking to dough phase. The results show the northern counties in corn belt area are less interfered by extreme heat but are more vulnerable to water deficiency.

Chorus Waves Modulation of Langmuir Waves in the Radiation Belts

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

Li, Jinxing; Bortnik, Jacob; An, Xin

Using high-resolution waveforms measured by the Van Allen Probes, we report a novel observation in the radiation belts. Namely, we show that multiband, discrete, rising-tone whistler-mode chorus emissions exhibit a one-to-one correlation with Langmuir wave bursts. Moreover, the periodic Langmuir wave bursts are generally observed at the phase location where the chorus wave E || component is oriented opposite to its propagation direction. The electron measurements show a beam in phase space density at the particle velocity that matches the parallel phase velocity of the chorus waves. Based on this evidence, we conclude that the chorus waves accelerate the suprathermalmore » electrons via Landau resonance, and generate a localized electron beam in phase space density. Consequently, the Langmuir waves are excited locally and are modulated by the chorus wave phase. As a result, this microscale interaction between chorus waves and high frequency electrostatic waves provides a new insight into the nonlinear wave-particle interaction process.« less

Chorus Waves Modulation of Langmuir Waves in the Radiation Belts

DOE PAGES

Li, Jinxing; Bortnik, Jacob; An, Xin; ...

2017-11-20

Using high-resolution waveforms measured by the Van Allen Probes, we report a novel observation in the radiation belts. Namely, we show that multiband, discrete, rising-tone whistler-mode chorus emissions exhibit a one-to-one correlation with Langmuir wave bursts. Moreover, the periodic Langmuir wave bursts are generally observed at the phase location where the chorus wave E || component is oriented opposite to its propagation direction. The electron measurements show a beam in phase space density at the particle velocity that matches the parallel phase velocity of the chorus waves. Based on this evidence, we conclude that the chorus waves accelerate the suprathermalmore » electrons via Landau resonance, and generate a localized electron beam in phase space density. Consequently, the Langmuir waves are excited locally and are modulated by the chorus wave phase. As a result, this microscale interaction between chorus waves and high frequency electrostatic waves provides a new insight into the nonlinear wave-particle interaction process.« less

49 CFR 585.22 - Purpose.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 7 2012-10-01 2012-10-01 false Purpose. 585.22 Section 585.22 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase...

49 CFR 585.22 - Purpose.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 7 2014-10-01 2014-10-01 false Purpose. 585.22 Section 585.22 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase...

49 CFR 585.22 - Purpose.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 7 2013-10-01 2013-10-01 false Purpose. 585.22 Section 585.22 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase...

49 CFR 585.25 - Records.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 7 2010-10-01 2010-10-01 false Records. 585.25 Section 585.25 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase...

49 CFR 585.22 - Purpose.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 7 2010-10-01 2010-10-01 false Purpose. 585.22 Section 585.22 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase...

49 CFR 585.22 - Purpose.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 7 2011-10-01 2011-10-01 false Purpose. 585.22 Section 585.22 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase...

Gradual Diffusion and Punctuated Phase Space Density Enhancements of Highly Relativistic Electrons: Van Allen Probes Observations

NASA Technical Reports Server (NTRS)

Baker, D. N.; Jaynes, A. N.; Li, X.; Henderson, M. G.; Kanekal, S. G.; Reeves, G. D.; Spence, H. E.; Claudepierre, S. G.; Fennell, J. F.; Hudson, M. K.

2014-01-01

The dual-spacecraft Van Allen Probes mission has provided a new window into mega electron volt (MeV) particle dynamics in the Earth's radiation belts. Observations (up to E (is) approximately 10MeV) show clearly the behavior of the outer electron radiation belt at different timescales: months-long periods of gradual inward radial diffusive transport and weak loss being punctuated by dramatic flux changes driven by strong solar wind transient events. We present analysis of multi-MeV electron flux and phase space density (PSD) changes during March 2013 in the context of the first year of Van Allen Probes operation. This March period demonstrates the classic signatures both of inward radial diffusive energization and abrupt localized acceleration deep within the outer Van Allen zone (L (is) approximately 4.0 +/- 0.5). This reveals graphically that both 'competing' mechanisms of multi-MeV electron energization are at play in the radiation belts, often acting almost concurrently or at least in rapid succession.

A Maximum Likelihood Ensemble Data Assimilation Method Tailored to the Inner Radiation Belt

NASA Astrophysics Data System (ADS)

Guild, T. B.; O'Brien, T. P., III; Mazur, J. E.

2014-12-01

The Earth's radiation belts are composed of energetic protons and electrons whose fluxes span many orders of magnitude, whose distributions are log-normal, and where data-model differences can be large and also log-normal. This physical system thus challenges standard data assimilation methods relying on underlying assumptions of Gaussian distributions of measurements and data-model differences, where innovations to the model are small. We have therefore developed a data assimilation method tailored to these properties of the inner radiation belt, analogous to the ensemble Kalman filter but for the unique cases of non-Gaussian model and measurement errors, and non-linear model and measurement distributions. We apply this method to the inner radiation belt proton populations, using the SIZM inner belt model [Selesnick et al., 2007] and SAMPEX/PET and HEO proton observations to select the most likely ensemble members contributing to the state of the inner belt. We will describe the algorithm, the method of generating ensemble members, our choice of minimizing the difference between instrument counts not phase space densities, and demonstrate the method with our reanalysis of the inner radiation belt throughout solar cycle 23. We will report on progress to continue our assimilation into solar cycle 24 using the Van Allen Probes/RPS observations.

Effects of Complex Interplanetary Structures on the Dynamics of the Earth's Outer Radiation Belt During the 16-30 September 2014 Period: II) Corotating Solar Wind Stream

NASA Astrophysics Data System (ADS)

Souza, V. M. C. E. S.; Da Silva, L. A.; Sibeck, D. G.; Alves, L. R.; Jauer, P. R.; Dias Silveira, M. V.; Medeiros, C.; Marchezi, J.; Rockenbach, M.; Baker, D. N.; Kletzing, C.; Kanekal, S. G.; Georgiou, M.; Mendes, O., Jr.; Dal Lago, A.; Vieira, L. E. A.

2015-12-01

We present a case study describing the dynamics of the outer radiation belt for two different solar wind conditions. First, we discuss a dropout of outer belt energetic electron fluxes corresponding to the arrival of an interplanetary coronal mass ejection (ICME) followed by a corotating stream in September 2014. Second, we discuss the reformation of the outer radiation belt that began on September 22nd. We find that the arrival of the ICME and the corotating interaction region that preceded the stream cause a long-duration (many day) dropout of high-energy electrons. The recovery in radiation belt fluxes only begins when the high-speed stream begins to develop IMF Bz fluctuations and auroral activity resumes. Furthermore, during periods in which several consecutive solar wind structures appear, the first structure primes the outer radiation belt prior to the interaction of the subsequent solar wind structures with the magnetosphere. Consequently, the evolution of the outer radiation belt through the solar cycle is significantly affected by the dominant structure of each phase of the cycle. We use energetic electron and magnetic field observations provided by the Van Allen Probes, THEMIS, and GOES missions.

Variation of Radiation Belt Content Indices and total electron energy During Magnetic Storms Based On Van Allen Probe Observations

NASA Astrophysics Data System (ADS)

Xiong, Y.; Xie, L.; Chen, L.; Pu, Z.

2017-12-01

We investigate the variability of the RBC indices and total electron energy for varying energies within outer belt during 42 isolate magnetic storms based on the electron flux data from MagEIS and REPT onboard Van Allen Probe-A spacecraft. Van Allan Probes travel throughout the entire radiation belt twice during each orbit, providing an excellent opportunity to measure the electron's pitch angle distributions near the magnetic equatorial plane which is essential to calculate the RBC index accurately. Instead of assuming an isotropic electron pitch angle distribution which is widely used in previous studies, we develop a new and reliable technique to infer the equatorial pitch angle distributions based on the off-equator measurements. The statistic results show that the total electron energy in outer belt increase in 80% storms and has a positive correlation with median value of AE during recovery phase and minimum -Dst. The possibility of observing RBC depletion increase at high energies. The upper limit energy of RBC enhancement has a positive correlation with median value of AE and Vsw during recovery phase and a negative correlation with median value of Nsw during storm, which is consist of the balance of acceleration by chorus waves and loss by EMIC waves.

Simple Fabrication of Gold Nanobelts and Patterns

PubMed Central

Zhang, Renyun; Hummelgård, Magnus; Olin, Håkan

2012-01-01

Gold nanobelts are of interest in several areas; however, there are only few methods available to produce these belts. We report here on a simple evaporation induced self-assembly (EISA) method to produce porous gold nanobelts with dimensions that scale across nanometer (thickness ∼80 nm) and micrometer (width ∼20 µm), to decimeter (length ∼0.15 m). The gold nanobelts are well packed on the beaker wall and can be easily made to float on the surface of the solution for depositing onto other substrates. Microscopy showed that gold nanobelts had a different structure on the two sides of the belt; the density of gold nanowires on one side was greater than on the other side. Electrical measurements showed that these nanobelts were sensitive to compressive or tensile forces, indicating a potential use as a strain sensor. The patterned nanobelts were further used as a template to grow ZnO nanowires for potential use in applications such as piezo-electronics. PMID:22291962

Venus tectonics - Initial analysis from Magellan

NASA Technical Reports Server (NTRS)

Solomon, Sean C.; Head, James W.; Kaula, William M.; Schubert, Gerald; Mckenzie, Dan

1991-01-01

The styles of lithospheric deformation, the inferred mechanical properties of the lithosphere, and their implications for the tectonic history of Venus are discussed on the basis of radar imaging and altimetry data from Magellan. Observations of the planet plains reveal a superposition of different episodes of deformation and volcanism, strain both distributed and concentrated into zones of extension and shortening, and features reflecting a crustal response to mantle dynamic processes. Lithospheric shortening and crustal thickening are represented by ridge belts and mountain belts. The latter show the evidence for extension and collapse both during and following crustal compression. Venus displays quasi-circular coronae and broad rises with linear rift zones, associated with significant volcanism. Large-offset strike-slip faults have not been observed, although horizontal shear is accommodated across broad zones of crustal shortening. On Venus strain is distributed across zones that are one to a few hundred kilometers wide, and separated by stronger and less deformed blocks hundreds of kilometers in width, as in actively deforming continental regions on earth.

49 CFR 585.21 - Scope.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 7 2014-10-01 2014-10-01 false Scope. 585.21 Section 585.21 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase-In...

49 CFR 585.21 - Scope.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 7 2013-10-01 2013-10-01 false Scope. 585.21 Section 585.21 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase-In...

49 CFR 585.21 - Scope.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 7 2012-10-01 2012-10-01 false Scope. 585.21 Section 585.21 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase-In...

49 CFR 585.21 - Scope.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 7 2011-10-01 2011-10-01 false Scope. 585.21 Section 585.21 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase-In...

49 CFR 585.21 - Scope.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 7 2010-10-01 2010-10-01 false Scope. 585.21 Section 585.21 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PHASE-IN REPORTING REQUIREMENTS Rear Inboard Lap/Shoulder Belt Phase-In...

The effects of magnetospheric processes on relativistic electron dynamics in the Earth's outer radiation belt

DOE PAGES

Tang, C. L.; Wang, Y. X.; Ni, B.; ...

2017-08-11

Using the electron phase space density (PSD) data measured by Van Allen Probe A from January 2013 to April 2015, we investigate the effects of magnetospheric processes on relativistic electron dynamics in the Earth's outer radiation belt during 50 geomagnetic storms. A statistical study shows that the maximum electron PSDs for various μ (μ = 630, 1096, 2290, and 3311 MeV/G) at L*~4.0 after the storm peak have good correlations with storm intensity (cc~0.70). This suggests that the occurrence and magnitude of geomagnetic storms are necessary for relativistic electron enhancements at the inner edge of the outer radiation belt (L*more » = 4.0). For moderate or weak storm events (SYM–H min > ~–100 nT) with weak substorm activity (AE max < 800 nT) and strong storm events (SYM–H min ≤ ~–100 nT) with intense substorms (AE max ≥ 800 nT) during the recovery phase, the maximum electron PSDs for various μ at different L* values (L* = 4.0, 4.5, and 5.0) are well correlated with storm intensity (cc > 0.77). For storm events with intense substorms after the storm peak, relativistic electron enhancements at L* = 4.5 and 5.0 are observed. This shows that intense substorms during the storm recovery phase are crucial to relativistic electron enhancements in the heart of the outer radiation belt. In conclusion, our statistics study suggests that magnetospheric processes during geomagnetic storms have a significant effect on relativistic electron dynamics.« less

The effects of magnetospheric processes on relativistic electron dynamics in the Earth's outer radiation belt

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

Tang, C. L.; Wang, Y. X.; Ni, B.

Using the electron phase space density (PSD) data measured by Van Allen Probe A from January 2013 to April 2015, we investigate the effects of magnetospheric processes on relativistic electron dynamics in the Earth's outer radiation belt during 50 geomagnetic storms. A statistical study shows that the maximum electron PSDs for various μ (μ = 630, 1096, 2290, and 3311 MeV/G) at L*~4.0 after the storm peak have good correlations with storm intensity (cc~0.70). This suggests that the occurrence and magnitude of geomagnetic storms are necessary for relativistic electron enhancements at the inner edge of the outer radiation belt (L*more » = 4.0). For moderate or weak storm events (SYM–H min > ~–100 nT) with weak substorm activity (AE max < 800 nT) and strong storm events (SYM–H min ≤ ~–100 nT) with intense substorms (AE max ≥ 800 nT) during the recovery phase, the maximum electron PSDs for various μ at different L* values (L* = 4.0, 4.5, and 5.0) are well correlated with storm intensity (cc > 0.77). For storm events with intense substorms after the storm peak, relativistic electron enhancements at L* = 4.5 and 5.0 are observed. This shows that intense substorms during the storm recovery phase are crucial to relativistic electron enhancements in the heart of the outer radiation belt. In conclusion, our statistics study suggests that magnetospheric processes during geomagnetic storms have a significant effect on relativistic electron dynamics.« less

Geometry and kinematics of the fold-thrust belt and structural evolution of the major Himalayan fault zones in the Darjeeling -- Sikkim Himalaya, India

NASA Astrophysics Data System (ADS)

Bhattacharyya, Kathakali

The Darjeeling-Sikkim Himalaya lies in the eastern part of the Himalayan fold-thrust belt (FTB) in a zone of high arc-perpendicular convergence between the Indian and Eurasian plates. In this region two distinct faults form the Main Central thrust (MCT), the structurally higher MCT1 and the lower MCT2; both these faults have translated the Greater Himalayan hanging wall rocks farther towards the foreland than in the western Himalaya. The width of the sub-MCT Lesser Himalayan rocks progressively decreases from the western Himalaya to this part of the eastern Himalaya, and as a result, the width of the FTB is narrower in this region compared to the western Himalaya. Our structural analysis shows that in the Darjeeling-Sikkim Himalaya the sub-MCT Lesser Himalayan duplex is composed of two duplex systems and has a more complex geometry than in the rest of the Himalayan fold-thrust belt. The structurally higher Dating duplex is a hinterland-dipping duplex; the structurally lower Rangit duplex varies in geometry from a hinterland-dipping duplex in the north to an antiformal stack in the middle and a foreland-dipping duplex in the south. The MCT2 is the roof thrust of the Daling duplex and the Ramgarh thrust is the roof thrust of the Rangit duplex. In this region, the Ramgarh thrust has a complex structural history with continued reactivation during footwall imbrication. The foreland-dipping component of the Rangit duplex, along with the large displacement associated with the reactivation of the Ramgarh thrust accounts for the large translation of the MCT sheets in the Darjeeling-Sikkim Himalaya. The growth of the Lesser Himalayan duplex modified the final geometry of the overlying MCT sheets, resulting in a plunge culmination that manifests itself as a broad N-S trending "anticline" in the Darjeeling-Sikkim Himalaya. This is not a "river anticline" as its trace lies west of the Teesta river. A transport parallel balanced cross section across this region has accommodated a total minimum shortening of ˜502 km (˜82%) south of the South Tibetan Detachment system (STDS). Based on this shortening, the average long-term shortening rate is estimated to be ˜22mm/yr in this region. The available shortening estimates from different parts of the Himalayan arc show significant variations in shortening, but based on the present available data, it is difficult to evaluate the primary cause for this variation. The shortening in the Himalayan fold-thrust belt (FTB) is highest in the middle of the Himalayan arc (western Nepal) and progressively decreases towards the two syntaxes. Although the width of the Lesser Himalayan belt decreases in the eastern Himalaya, the Lesser Himalayan shortening percentage remains approximately similar to that in the Nepal Himalaya. In addition, the shortening accommodated within the Lesser Himalayan duplex progressively increases from the western to the eastern Himalaya where it accommodates nearly half of the total shortening. The regional restorations suggest that the width of the original Lesser Himalayan basin may have played an important role in partitioning the shortening in the Himalayan FTB. In addition, the retrodeformed cross section in the Darjeeling-Sikkim Himalaya provides insights into the palinspastic reconstruction of the Gondwana basin of Peninsular India, suggesting that this basin extended ˜150 km northward of its present northernmost exposure in this region. The balanced cross section suggests that each of the MCT sheets has undergone translation of ≥100km in this region. Although a regional scale flat-on-flat relationship is seen in the MCT sheets, there is a significant variation in overburden from the trailing portion to the leading edge of the MCT due to the geometry of the tapered crystalline orogenic wedge. Microstructural studies from three segments of the MCT2 fault zone suggest that the MCT2 zone has undergone strain softening by different mechanisms along different portions of its transport-parallel length, mainly as a result of changing overburden conditions. This regional strain softening provides a suitable explanation for the large translation of ≥100 km along a relatively thin MCT2 fault zone in the Darjeeling-Sikkim Himalaya.

Measurement of the CP-violating phase Φ s and the B s 0 meson decay width difference with B s 0 → J/ψΦ decays in ATLAS

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2016-08-24

Here, a measurement of the B s 0 decay parameters in the B s 0 → J/ψΦ channel using an integrated luminosity of 14.3 fb –1 collected by the ATLAS detector from 8 TeV pp collisions at the LHC is presented. The measured parameters include the CP -violating phase Φ s, the decay width Γ s and the width difference between the mass eigenstates ΔΓ s.

Measurement of the CP-violating phase Φ s and the B s 0 meson decay width difference with B s 0 → J/ψΦ decays in ATLAS

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

Aad, G.; Abbott, B.; Abdallah, J.

Here, a measurement of the B s 0 decay parameters in the B s 0 → J/ψΦ channel using an integrated luminosity of 14.3 fb –1 collected by the ATLAS detector from 8 TeV pp collisions at the LHC is presented. The measured parameters include the CP -violating phase Φ s, the decay width Γ s and the width difference between the mass eigenstates ΔΓ s.

Review of GEM Radiation Belt Dropout and Buildup Challenges

NASA Astrophysics Data System (ADS)

Tu, Weichao; Li, Wen; Morley, Steve; Albert, Jay

2017-04-01

In Summer 2015 the US NSF GEM (Geospace Environment Modeling) focus group named "Quantitative Assessment of Radiation Belt Modeling" started the "RB dropout" and "RB buildup" challenges, focused on quantitative modeling of the radiation belt buildups and dropouts. This is a community effort which includes selecting challenge events, gathering model inputs that are required to model the radiation belt dynamics during these events (e.g., various magnetospheric waves, plasmapause and density models, electron phase space density data), simulating the challenge events using different types of radiation belt models, and validating the model results by comparison to in situ observations of radiation belt electrons (from Van Allen Probes, THEMIS, GOES, LANL/GEO, etc). The goal is to quantitatively assess the relative importance of various acceleration, transport, and loss processes in the observed radiation belt dropouts and buildups. Since 2015, the community has selected four "challenge" events under four different categories: "storm-time enhancements", "non-storm enhancements", "storm-time dropouts", and "non-storm dropouts". Model inputs and data for each selected event have been coordinated and shared within the community to establish a common basis for simulations and testing. Modelers within and outside US with different types of radiation belt models (diffusion-type, diffusion-convection-type, test particle codes, etc.) have participated in our challenge and shared their simulation results and comparison with spacecraft measurements. Significant progress has been made in quantitative modeling of the radiation belt buildups and dropouts as well as accessing the modeling with new measures of model performance. In this presentation, I will review the activities from our "RB dropout" and "RB buildup" challenges and the progresses achieved in understanding radiation belt physics and improving model validation and verification.

More symmetrical gait after split-belt treadmill walking does not modify dynamic and postural balance in individuals post-stroke.

PubMed

Miéville, Carole; Lauzière, Séléna; Betschart, Martina; Nadeau, Sylvie; Duclos, Cyril

2018-04-24

Spontaneous gait is often asymmetrical in individuals post-stroke, despite their ability to walk more symmetrically on demand. Given the sensorimotor deficits in the paretic limb, this asymmetrical gait may facilitate balance maintenance. We used a split-belt walking protocol to alter gait asymmetry and determine the effects on dynamic and postural balance. Twenty individuals post-stroke walked on a split-belt treadmill. In two separate periods, the effects of walking with the non-paretic leg, and then the paretic one, on the faster belt on spatio-temporal symmetry and balance were compared before and after these perturbation periods. Kinematic and kinetic data were collected using a motion analysis system and an instrumented treadmill to determine symmetry ratios of spatiotemporal parameters and dynamic and postural balance. Balance, quantified by the concepts of stabilizing and destabilizing forces, was compared before and after split-belt walking for subgroups of participants who improved and worsened their symmetry. The side on the slow belt during split-belt walking, but not the changes in asymmetry, affected balance. Difficulty in maintaining balance was higher during stance phase of the leg that was on the slow belt and lower on the contralateral side after split-belt walking, mostly because the center of pressure was closer (higher difficulty) or further (lower difficulty) from the limit of the base of support, respectively. Changes in spatiotemporal parameters may be sought without additional alteration of balance during gait post-stroke. Copyright © 2018 Elsevier Ltd. All rights reserved.

Thermobarometric constraints on mid-Cretaceous to late Cretaceous metamorphic events in the western metamorphic belt of the Coast Mountains complex near Petersburg, southeastern Alaska

USGS Publications Warehouse

Himmelberg, Glen R.; Brew, David A.

2005-01-01

The western metamorphic belt is part of the Coast Mountains Complex of southeastern Alaska and western Canada. This complex formed as a result of mid-Cretaceous through middle Eocene crustal shortening between the previously amalgamated Wrangellia and Alexander terranes (Insular superterrane) and previously accreted terranes of the North American continental margin (Intermontane superterrane). The western metamorphic belt, which ranges from a few kilometers to several tens of kilometers in width, records a complex sequence of contact-metamorphic and regional metamorphic events, the most significant of which are designated M1R, M2C-R, and M3R. The M1R regional metamorphic event ranged in grade from subgreenschist to greenschist facies and was overprinted by the M2C-R and M3R metamorphic events. The M2C-R metamorphic event is recorded in discrete contact-metamorphic aureoles and regional metamorphic-mineral assemblages related to tonalite-granodiorite plutons of the Admiralty-Revillagigedo plutonic belt. The M3R metamorphic belt, which is adjacent to the M2C-R belt, is characterized by regional Barrovian isograds of garnet, staurolite, kyanite, and sillimanite. Using the THERMOCALC program, pressure-temperature (P-T) conditions for the M2C-R metamorphic event are estimated to be in the ranges 5.3-7.5 kbars and 525-640 deg.C and for the M3R metamorphic event in the ranges 9.4-12.6 kbars and 730-895 deg.C. The M2C-R metamorphic event occurred at approximately 90 Ma, but the timing of the M3R metamorphic event is poorly documented and uncertain. On the basis of an 40Ar/39Ar age on actinolitic amphibole and a Sm-Nd age on garnet core, the timing of metamorphism might be constrained between 90+/-1 and 80+/-9 Ma, although the Sm-Nd age of 80+/-9 m.y. possibly reflects postpeak growth. Thermobarometric data suggest that the two events occurred at different crustal levels and followed different P-T paths. No evidence exists that M2C-R metamorphic-mineral assemblages were overprinted by the M3R metamorphic event, as proposed by some workers. Juxtaposition of the two belts of rocks probably occurred along the Coast shear zone during uplift and exhumation of the Coast Mountains.

Controlling the Temperature and Speed of the Phase Transition of VO 2 Microcrystals

DOE PAGES

Yoon, Joonseok; Kim, Howon; Chen, Xian; ...

2015-12-29

Here, we investigated the control of two important parameters of vanadium dioxide (VO 2 ) microcrystals, the phase transition temperature and speed, by varying microcrystal width. By using the reflectivity change between insulating and metallic phases, phase transition temperature is measured by optical microscopy. As the width of square cylinder-shaped microcrystals decreases from ~70 to ~1 μm, the phase transition temperature (67 °C for bulk) varied as much as 26.1 °C (19.7 °C) during heating (cooling). In addition, the propagation speed of phase boundary in the microcrystal, i.e., phase transition speed, is monitored at the onset of phase transition bymore » using the high-speed resistance measurement. The phase transition speed increases from 4.6 × 10 2 to 1.7 × 10 4 μm/s as the width decreases from ~50 to ~2 μm. While the statistical description for a heterogeneous nucleation process explains the size dependence on phase transition temperature of VO 2 , the increase of effective thermal exchange process is responsible for the enhancement of phase transition speed of small VO 2 microcrystals. These findings not only enhance the understanding of VO 2 intrinsic properties but also contribute to the development of innovative electronic devices.« less

Controlling the Temperature and Speed of the Phase Transition of VO 2 Microcrystals

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

Yoon, Joonseok; Kim, Howon; Chen, Xian

Here, we investigated the control of two important parameters of vanadium dioxide (VO 2 ) microcrystals, the phase transition temperature and speed, by varying microcrystal width. By using the reflectivity change between insulating and metallic phases, phase transition temperature is measured by optical microscopy. As the width of square cylinder-shaped microcrystals decreases from ~70 to ~1 μm, the phase transition temperature (67 °C for bulk) varied as much as 26.1 °C (19.7 °C) during heating (cooling). In addition, the propagation speed of phase boundary in the microcrystal, i.e., phase transition speed, is monitored at the onset of phase transition bymore » using the high-speed resistance measurement. The phase transition speed increases from 4.6 × 10 2 to 1.7 × 10 4 μm/s as the width decreases from ~50 to ~2 μm. While the statistical description for a heterogeneous nucleation process explains the size dependence on phase transition temperature of VO 2 , the increase of effective thermal exchange process is responsible for the enhancement of phase transition speed of small VO 2 microcrystals. These findings not only enhance the understanding of VO 2 intrinsic properties but also contribute to the development of innovative electronic devices.« less

Nonstorm time dropout of radiation belt electron fluxes on 24 September 2013

DOE PAGES

Su, Zhenpeng; Gao, Zhonglei; Reeves, Geoffrey D.; ...

2016-07-01

Radiation belt electron flux dropouts during the main phase of geomagnetic storms have received increasing attention in recent years. Here we focus on a rarely reported nonstorm time dropout event observed by Van Allen Probes on 24 September 2013. Within several hours, the radiation belt electron fluxes exhibited a significant (up to 2 orders of magnitude) depletion over a wide range of radial distances ( L > 4.5), energies (~500 keV to several MeV) and equatorial pitch angles (0° ≤ α e ≤ 180°). STEERB simulations show that the relativistic electron loss in the region L = 4.5–6.0 was primarilymore » caused by the pitch angle scattering of observed plasmaspheric hiss and electromagnetic ion cyclotron waves. Furthermore, our results emphasize the complexity of radiation belt dynamics and the importance of wave-driven precipitation loss even during nonstorm times.« less

Nonstorm time dropout of radiation belt electron fluxes on 24 September 2013

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

Su, Zhenpeng; Gao, Zhonglei; Reeves, Geoffrey D.

Radiation belt electron flux dropouts during the main phase of geomagnetic storms have received increasing attention in recent years. Here we focus on a rarely reported nonstorm time dropout event observed by Van Allen Probes on 24 September 2013. Within several hours, the radiation belt electron fluxes exhibited a significant (up to 2 orders of magnitude) depletion over a wide range of radial distances ( L > 4.5), energies (~500 keV to several MeV) and equatorial pitch angles (0° ≤ α e ≤ 180°). STEERB simulations show that the relativistic electron loss in the region L = 4.5–6.0 was primarilymore » caused by the pitch angle scattering of observed plasmaspheric hiss and electromagnetic ion cyclotron waves. Furthermore, our results emphasize the complexity of radiation belt dynamics and the importance of wave-driven precipitation loss even during nonstorm times.« less

New observations of the low energy proton inner belt

NASA Astrophysics Data System (ADS)

Guild, T. B.; Mazur, J. E.; Looper, M. D.; Blake, J. B.

2013-12-01

We present preliminary results of the trapped low energy (6-32 MeV) proton population in the inner radiation belt (L>1.8) from May, 2008 through present. These observations were made by the High Linear Energy Transfer (HiLET) proton telescope, part of the TWIN-ES instrument suite on the TWINS-2 spacecraft. This collimated telescope measures pitch-angle-resolved proton fluxes as it rises through the inner radiation belt twice per day. We present pitch angle distributions of low energy protons as a function of L, and show how the flux and pitch angle distributions change from the deep solar minimum of 2009 through the rising phase of solar cycle 24. Particular emphasis will be given to inner belt dynamics throughout this interval, both gradual and abrupt, and a discussion of the candidate processes responsible for these changes will be given.

Nonstorm time dropout of radiation belt electron fluxes on 24 September 2013

NASA Astrophysics Data System (ADS)

Su, Zhenpeng; Gao, Zhonglei; Zhu, Hui; Li, Wen; Zheng, Huinan; Wang, Yuming; Wang, Shui; Spence, H. E.; Reeves, G. D.; Baker, D. N.; Blake, J. B.; Funsten, H. O.; Wygant, J. R.

2016-07-01

Radiation belt electron flux dropouts during the main phase of geomagnetic storms have received increasing attention in recent years. Here we focus on a rarely reported nonstorm time dropout event observed by Van Allen Probes on 24 September 2013. Within several hours, the radiation belt electron fluxes exhibited a significant (up to 2 orders of magnitude) depletion over a wide range of radial distances (L > 4.5), energies (˜500 keV to several MeV) and equatorial pitch angles (0°≤αe≤180°). STEERB simulations show that the relativistic electron loss in the region L = 4.5-6.0 was primarily caused by the pitch angle scattering of observed plasmaspheric hiss and electromagnetic ion cyclotron waves. Our results emphasize the complexity of radiation belt dynamics and the importance of wave-driven precipitation loss even during nonstorm times.

Checking the compatibility of the cold Kuiper belt with a planetary instability migration model

NASA Astrophysics Data System (ADS)

Gomes, Rodney; Nesvorný, David; Morbidelli, Alessandro; Deienno, Rogerio; Nogueira, Erica

2018-05-01

The origin of the orbital structure of the cold component of the Kuiper belt is still a hot subject of investigation. Several features of the solar system suggest that the giant planets underwent a phase of global dynamical instability, but the actual dynamical evolution of the planets during the instability is still debated. To explain the structure of the cold Kuiper belt, Nesvorny (2015, AJ 150,68) argued for a "soft" instability, during which Neptune never achieved a very eccentric orbit. Here we investigate the possibility of a more violent instability, from an initially more compact fully resonant configuration of 5 giant planets. We show that the orbital structure of the cold Kuiper belt can be reproduced quite well provided that the cold population formed in situ, with an outer edge between 44 - 45 au and never had a large mass.

Winds Near Jupiter's Belt-Zone Boundary

NASA Technical Reports Server (NTRS)

1997-01-01

Time Sequence of a belt-zone boundary near Jupiter's equator. These mosaics show Jupiter's appearance at 757 nanometers (near-infrared) and were taken nine hours apart. Images at 757 nanometers show features of Jupiter's primary visible cloud deck.

Jupiter's atmospheric circulation is dominated by alternating jets of east/west (zonal) winds. The bands have different widths and wind speeds but have remained constant as long as telescopes and spacecraft have measured them. A strong eastward jet is made visible as it stretches the clouds just below the center of this mosaic. The maximum wind speed of this jet is 128 meters per second (286 miles per hour). Features on this jet move about one quarter of the width of the mosaic. All the features visible in these mosaics are moving eastward (right).

North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Water Ice on Kuiper Belt Object 1996 TO66

NASA Technical Reports Server (NTRS)

Brown, R. H.; Cruikshank, D. P.; Pendleton, Y.

1999-01-01

The 1.40-2.40 micron spectrum of Kuiper Belt object (KBO) 1996 TO66 was measured at the Keck Observatory in September 1998. It's spectrum shows the strong absorptions near 1.5 and 2.0 micron characteristic of water ice--the first such detection on a Kuiper Belt object. The depth of the absorption bands and the continuum reflectance of 1996 TO66 also suggest the presence of a black to slightly blue-colored, spectrally featureless particulate material as a minority component mixed with the water ice. In addition, there is evidence that the intensity of the water bands in the spectrum of 1996 TO66 vary with rotational phase suggesting that it has a "patchy" surface.

Accelerometer-Based Method for Extracting Respiratory and Cardiac Gating Information for Dual Gating during Nuclear Medicine Imaging

PubMed Central

Pänkäälä, Mikko; Paasio, Ari

2014-01-01

Both respiratory and cardiac motions reduce the quality and consistency of medical imaging specifically in nuclear medicine imaging. Motion artifacts can be eliminated by gating the image acquisition based on the respiratory phase and cardiac contractions throughout the medical imaging procedure. Electrocardiography (ECG), 3-axis accelerometer, and respiration belt data were processed and analyzed from ten healthy volunteers. Seismocardiography (SCG) is a noninvasive accelerometer-based method that measures accelerations caused by respiration and myocardial movements. This study was conducted to investigate the feasibility of the accelerometer-based method in dual gating technique. The SCG provides accelerometer-derived respiratory (ADR) data and accurate information about quiescent phases within the cardiac cycle. The correct information about the status of ventricles and atria helps us to create an improved estimate for quiescent phases within a cardiac cycle. The correlation of ADR signals with the reference respiration belt was investigated using Pearson correlation. High linear correlation was observed between accelerometer-based measurement and reference measurement methods (ECG and Respiration belt). Above all, due to the simplicity of the proposed method, the technique has high potential to be applied in dual gating in clinical cardiac positron emission tomography (PET) to obtain motion-free images in the future. PMID:25120563

Structure sismique du socle paléozoïque du bassin des Doukkala, Môle côtier, Maroc occidental. Indication en faveur de l'existence d'une phase éo-varisqueSeismic structure of the Doukkala basin, Palaeozoic basement, western Morocco: a hint for an Eovariscan fold-and-thrust belt

NASA Astrophysics Data System (ADS)

Echarfaoui, Hassan; Hafid, Mohamed; Salem, Abdallah Aı̈t

2002-01-01

Seismic profiles and well data from the Doukkala basin unravel the structure of the Palaeozoic basement and suggest that this coastal zone of western Morocco was affected by a compressive phase during the Frasnian. This resulted in the formation of upright, plurikilometric folds associated with reverse faults (North Doukkala), and of asymmetrical folds associated with mostly west verging ramps (South Doukkala). Folding involved all pre-Upper Frasnian formations and caused partial or total hiatus of Upper Frasnian-Strunian strata. This event can be correlated with the orogenic phase reported from more internal domains of the Morocco Hercynian belt, where it is referred to as the 'Bretonne' or 'Eovariscan' phase. To cite this article: H. Echarfaoui et al., C. R. Geoscience 334 (2002) 13-20

The radiation belts and ring current: the relationship between Dst and relativistic electron phase space density

NASA Astrophysics Data System (ADS)

Grande, M.; Carter, M.; Perry, C. H.

2002-03-01

We briefly review the radiation belts, before moving on to a more detailed examination of the relationship between the Disturbance Storm Time Index (Dst) and relativistic electron flux. We show that there is a strong correlation between the growth phase of storms, as represented by Dst, and dropouts in electron flux. Recovery is accompanied by growth of the electron flux. We calculate Electron Phase Space Density (PSD) as a function of adiabatic invariants using electron particle mesurements from the Imaging Electron Sensor (IES) and the High Sensitivity Telescope (HIST) on the CEPPAD experiment onboard POLAR. We present the time history of the phase space density through the year 1998 as L-sorted plots and look in detail at the May 98 storm. Comparison with the Tsyganenko 96 magnetic field model prediction for the last closed field line suggests that the loss of electrons may be directly caused by the opening of drift shells.

The scattered disk and hot belt, two sides of the same coin?

NASA Astrophysics Data System (ADS)

Kavelaars, J. J.; Petit, J.-M.; Gladman, B.; Jone, R. L.; Parker, J.; Taylor, M.

2011-10-01

The Canada-France Ecliptic Plane Survey (CFEPS) and High Latitude Extension (HILat)[] obtained characterized observations of nearly 800 sq.deg. of sky to depths in the range ˜23.5 - 24.4 AB mag, providing a database of nearly 200 trans-neptunian objects (TNOs) with high-precision dynamical classification and known discovery efficiency. Using this database, we find that the high-inclination component of the inner (a < 40 AU) main (a=40-47 AU) classical and outer (a > 47 AU) belt are well represented by a continuous density distribution coming from a constrained q range (35 < q < 40). This range of peri-center is similar to the range which some researchers associated with the scattered disk. In our modeling of the orbital phase space of the Kuiper belt we find that there is no need for two distinct components (ie. both a scattered disk and a hot component to the classical belt). The historical separation of the high-inclination component of the Kuiper belt into these two distinct structures appears to have been mis-guided.

Exposure strategy and crystallization of Ge-Sb-Te thin film by maskless phase-change lithography

NASA Astrophysics Data System (ADS)

Ni, Ri Wen; Zeng, Bi Jian; Huang, Jun Zhu; Luo, Teng; Li, Zhen; Miao, Xiang Shui

2015-04-01

Maskless phase-change lithographic technology is developed as a photoresist of phase-change materials. The controllable growth behavior of the crystallization region on an amorphous thin film of Ge2Sb2Te5 (GST) irradiated by a laser beam is investigated; the GST thin film is deposited on a silicon substrate by the sputtering method. The results of a series of the experiments and the simulations all show that the width of a crystalline pattern is not only closely related to laser power and pulse duration, but also is apparently affected by the interactive area between the focused laser spot and thin film. The width maintains a nonlinear growth with the enhancement of the laser power until the thin film approaches melting, whereas it gradually reaches a constant value due to the local thermal equilibrium. This equilibrium makes the width irrelevant to the moving velocity with certain constraints when the laser works in continuous-wave mode. Within a defocus range of 15 μm, the widths of the crystalline patterns are obtained in a broad range from 690 nm to 8.13 μm under a 0.4-NA objective lens. By adjusting the defocus amount, some crystalline square patterns with expected widths in a wide range are fabricated, and the mean percentage error between the expected and fabricated widths is only 1.495%.

The gabbro-eclogite phase transition and the elevation of mountain belts on Venus

NASA Astrophysics Data System (ADS)

Namiki, Noriyuki; Solomon, Sean C.

1992-12-01

Among the four mountain belts surrounding Lakshmi Planum, Maxwell Montes is the highest and stands up to 11 km above the mean planetary radius and 7 km above Lakshmi Planum. The bulk composition and radioactive heat production of the crust on Venus, where measured, are similar to those of terrestrial tholeiitic basalt. Because the thickness of the low-density crust may be limited by the gabbro-garnet granulite-eclogite phase transitions, the 7-11 km maximum elevation of Maxwell Montes is difficult to understand except in the unlikely situation that the crust contains a large volume of magma. A possible explanation is that the base of the crust is not in phase equilibrium. It has been suggested that under completely dry conditions, the gabbro-eclogite phase transition takes place by solid-state diffusion and may require a geologically significant time to run to completion. Solid-state diffusion is a strongly temperature-dependent process. In this paper we solve the thermal evolution of the mountain belt to attempt to constrain the depth of the gabbro-eclogite transition and thus to assess this hypothesis quantitatively. The one-dimensional heat equation is solved numerically by a finite difference approximation. The deformation of the horizontally shortening crustal and mantle portions of the thermal boundary layer is assumed to occur by pure shear, and therefore the vertical velocity is given by the product of the horizontal strain rate and depth.

The gabbro-eclogite phase transition and the elevation of mountain belts on Venus

NASA Technical Reports Server (NTRS)

Namiki, Noriyuki; Solomon, Sean C.

1992-01-01

Among the four mountain belts surrounding Lakshmi Planum, Maxwell Montes is the highest and stands up to 11 km above the mean planetary radius and 7 km above Lakshmi Planum. The bulk composition and radioactive heat production of the crust on Venus, where measured, are similar to those of terrestrial tholeiitic basalt. Because the thickness of the low-density crust may be limited by the gabbro-garnet granulite-eclogite phase transitions, the 7-11 km maximum elevation of Maxwell Montes is difficult to understand except in the unlikely situation that the crust contains a large volume of magma. A possible explanation is that the base of the crust is not in phase equilibrium. It has been suggested that under completely dry conditions, the gabbro-eclogite phase transition takes place by solid-state diffusion and may require a geologically significant time to run to completion. Solid-state diffusion is a strongly temperature-dependent process. In this paper we solve the thermal evolution of the mountain belt to attempt to constrain the depth of the gabbro-eclogite transition and thus to assess this hypothesis quantitatively. The one-dimensional heat equation is solved numerically by a finite difference approximation. The deformation of the horizontally shortening crustal and mantle portions of the thermal boundary layer is assumed to occur by pure shear, and therefore the vertical velocity is given by the product of the horizontal strain rate and depth.

Mercury from mineral deposits and potential environmental impact

USGS Publications Warehouse

Rytuba, J.J.

2003-01-01

Mercury deposits are globally distributed in 26 mercury mineral belts. Three types of mercury deposits occur in these belts: silica-carbonate, hot-spring, and Almaden. Mercury is also produced as a by-product from several types of gold-silver and massive sulfide deposits, which account for 5% of the world's production. Other types of mineral deposits can be enriched in mercury and mercury phases present are dependent on deposit type. During processing of mercury ores, secondary mercury phases form and accumulate in mine wastes. These phases are more soluble than cinnabar, the primary ore mineral, and cause mercury deposits to impact the environment more so than other types of ore deposits enriched in mercury. Release and transport of mercury from mine wastes occur primarily as mercury-enriched particles and colloids. Production from mercury deposits has decreased because of environmental concerns, but by-product production from other mercury-enriched mineral deposits remains important.

A radiation hardened digital fluxgate magnetometer for space applications

NASA Astrophysics Data System (ADS)

Miles, D. M.; Bennest, J. R.; Mann, I. R.; Millling, D. K.

2013-09-01

Space-based measurements of Earth's magnetic field are required to understand the plasma processes responsible for energising particles in the Van Allen radiation belts and influencing space weather. This paper describes a prototype fluxgate magnetometer instrument developed for the proposed Canadian Space Agency's (CSA) Outer Radiation Belt Injection, Transport, Acceleration and Loss Satellite (ORBITALS) mission and which has applications in other space and suborbital applications. The magnetometer is designed to survive and operate in the harsh environment of Earth's radiation belts and measure low-frequency magnetic waves, the magnetic signatures of current systems, and the static background magnetic field. The new instrument offers improved science data compared to its predecessors through two key design changes: direct digitisation of the sensor and digital feedback from two cascaded pulse-width modulators combined with analog temperature compensation. These provide an increase in measurement bandwidth up to 450 Hz with the potential to extend to at least 1500 Hz. The instrument can resolve 8 pT on a 65 000 nT field with a magnetic noise of less than 10 pT/√Hz at 1 Hz. This performance is comparable with other recent digital fluxgates for space applications, most of which use some form of sigma-delta (ΣΔ) modulation for feedback and omit analog temperature compensation. The prototype instrument was successfully tested and calibrated at the Natural Resources Canada Geomagnetics Laboratory.

Fluvial sandstone reservoirs of Travis Peak (Hosston) Formation, east Texas basin

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

Tye, R.S.

1989-03-01

Gas production (7.2 billion ft/sup 3/) from low-permeability sandstones in the Travis Peak Formation, North Appleby field, Nacogdoches County, Texas, is enhanced through massive hydraulic fracturing of stacked sandstones that occur at depths between 8000 and 10,000 ft. stratigraphic reservoirs were formed in multilateral tabular sandstones owing to impermeable mudstone interbeds that encase blocky to upward-fining sandstones. Pervasive quartz cement in the sandstones decreases porosity and permeability and augments the reservoir seal. Subsurface data indicate that much of this 2000-ft thick section represents aggradation of alluvial-valley deposits. Multiple channel belts form a network of overlapping, broad, tabular sandstones having thickness-to-widthmore » ratios of 1:850 (8-44 ft thick; widths exceed 4-5 mi). Six to eight channel belts, each containing 80-90% medium to fine-grained sandstone, can occupy a 200-ft thick interval. In a vertical sequence through one channel belt sandstone, basal planar cross-bedding grades upward into thinly interbedded sets of planar cross-beds and ripple cross-lamination. Clay-clast conglomerates line scoured channel bases. Adjacent to the channels, interbedded mudstones accumulated in well-drained swamps and lakes. Poorly sorted sandstones represent overbank deposition (crevasse splays and lacustrine deltas). During Travis Peak deposition, fluvial styles evolved from dominantly braided systems near the base of the formation to more mud-rich, meandering systems at the top.« less

The radiation-belt electron phase-space-density response to stream-interaction regions: A study combining multi-point observations, data-assimilation, and physics-based modeling

NASA Astrophysics Data System (ADS)

Kellerman, A. C.; Shprits, Y.; McPherron, R. L.; Kondrashov, D. A.; Weygand, J. M.; Zhu, H.; Drozdov, A.

2017-12-01

Presented is an analysis of the phase-space density (PSD) response to the stream-interaction region (SIR), which utilizes a reanalysis dataset principally comprised of the data-assimilative Versatile Electron Radiation Belt (VERB) code, Van Allen Probe and GOES observations. The dataset spans the period 2012-2017, and includes several SIR (and CIR) storms. The PSD is examined for evidence of injections, transport, acceleration, and loss by considering the instantaneous and time-averaged change at adiabatic invariant values that correspond to ring-current, relativistic, and ultra-relativistic energies. In the solar wind, the following variables in the slow and fast wind on either side of the stream interface (SI) are considered in each case: the coronal hole polarity, IMF, solar wind speed, density, pressure, and SI tilt angle. In the magnetosphere, the Dst, AE, and past PSD state are considered. Presented is an analysis of the dominant mechanisms, both external and internal to the magnetosphere, that cause radiation-belt electron non-adiabatic changes during the passage of these fascinating solar wind structures.

Collisional emplacement history of the Naga-Andaman ophiolites and the position of the eastern Indian suture

NASA Astrophysics Data System (ADS)

Acharyya, S. K.

2007-02-01

Dismembered late Mesozoic ophiolites occur in two parallel belts along the eastern margin of the Indian Plate. The Eastern Belt, closely following the magmatic arc of the Central Burma Basin, coincides with a zone of high gravity. It is considered to mark a zone of steeply dipping mafic-ultramafic rocks and continental metamorphic rocks, which are the locus of two closely juxtaposed sutures. In contrast, the Western Belt, which follows the eastern margin of the Indo-Burma Range and the Andaman outer-island-arc, broadly follows a zone of negative gravity anomalies. Here the ophiolites occur mainly as rootless subhorizontal bodies overlying Eocene-Oligocene flyschoid sediments. Two sets of ophiolites that were accreted during the Early Cretaceous and mid-Eocene are juxtaposed in this belt. These are inferred to be westward propagated nappes from the Eastern Belt, emplaced during the late Oligocene collision between the Burmese and Indo-Burma-Andaman microcontinents. Ophiolite occurrences in the Andaman Islands belong to the Western Belt and are generally interpreted as upthrust oceanic crust, accreted due to prolonged subduction activity to the west of the island arc. This phase of subduction began only in the late Miocene and thus could not have produced the ophiolitic rocks, which were accreted in the late Early Eocene.

Magnetopause Losses of Radiation Belt Electrons During a Recent Magnetic Storm

NASA Astrophysics Data System (ADS)

Lemon, C. L.; Chen, M.; Roeder, J. L.; Fennell, J. F.; Mulligan, T. L.; Claudepierre, S. G.

2013-12-01

We present results from Van Allen Probes observations during the magnetic storm of June 1, 2013, and compare them with simulations of the same event using the RCM-E model. The RCM-E calculates ion and electron transport in self-consistently computed electric and magnetic fields. We examine the effect of the perturbed ring current magnetic field on the transport of energetic electrons, and the significance of this transport for explaining the observed evolution of radiation belt fluxes during this event. The event is notable because it is a relatively simple storm in which strong convection persists for approximately 7 hours, injecting a moderately strong ring current (minimum Dst of -120 nT); convection then quickly shuts off, leading to a long and smooth recovery phase. We use RCM-E simulations, constrained by Van Allen Probes data, to asses the rate of magnetopause losses of electrons (magnetopause shadowing), and to calculate electron drift times and the evolution of electron phase space densities during the storm event. We recently modified the RCM-E plasma drift calculations to include relativistic treatment of electrons and a more realistic electron loss model. The new electron loss model, although still somewhat simplistic, gives much more accurate loss rates in the inner magnetosphere (including the radiation belts), which significantly affects the resulting electron fluxes compared to previous simulations. This, in turn, modifies the transport of ions and electrons via feedback with both the electric and magnetic fields. Our results highlight the effect of the ring current on the evolution of the radiation belt electrons, with particular emphasis on the role that magnetopause losses play in the observed variation of radiation belt electron fluxes during the storm.

First thermochronological constraints on the Cenozoic extension along the Balkan fold-thrust belt (Central Stara Planina Mountains, Bulgaria)

NASA Astrophysics Data System (ADS)

Kounov, Alexandre; Gerdjikov, Ianko; Vangelov, Dian; Balkanska, Eleonora; Lazarova, Anna; Georgiev, Stoyan; Blunt, Edward; Stockli, Daniel

2017-11-01

The Balkan fold-thrust belt, exposed in Bulgaria and north-east Serbia, is part of the north-east vergent segment of the bi-vergent Eastern Mediterranean Alpine orogen. It was formed during two distinct compressional stages; the first one lasted from the Middle Jurassic to the Early Cretaceous and the second from Late Cretaceous to the Paleogene. Although the compressional tectonic evolution of the Balkan fold-thrust belt since the Middle Jurassic and during most of the Mesozoic is relatively well studied, the final exhumation of the rocks of the belt during the Cenozoic has remained poorly understood. Here, we present the first thermochronological constraints, based on fission-track and [U-Th-(Sm)]/He analysis, showing that along the central part of the belt syn- to post-orogenic extension could have started as early as the middle Eocene. Low-temperature thermochronological analysis of samples collected from three areas reveals at least two phases of increased cooling and exhumation during the Cenozoic. The first exhumation phase took place between 44 and 30 Ma and appears to be related to the syn- to post-orogenic collapse coeval with the earliest Cenozoic extensional stage observed across the southern Balkan Peninsula. A period of relative quiescence (between 30 and 25 Ma) is followed by the next cooling stage, between 25 and 20 Ma, which appears to be related to late Oligocene to early Miocene crustal extension across the Balkan Peninsula. Extension accommodated by the late Miocene to Recent age Sub-Balkan Graben System does not appear to have produced exhumation of rocks from beneath 2-4 km depth, as it was not detected by the low-temperature thermochronological methods applied in this study.

Investigating Stimulated Wave-Particle Interaction of Radiation Belt Particles with Space-Borne Whistler Mode Transmitters

DTIC Science & Technology

2009-03-30

presented. ii Figure 12. Arrival time of electrons during the positive phase of charge on the antenna. ........ 15 The distances...relativistic electrons in the radiation belt. The target electrons are in the energy range of 0.5~3.0 MeV in the region between L = 1.7~2.2, where L is the...waves to pitch-angle diffuse the electrons into the loss-cone, i.e., to precipitate the relativistic electrons into the neutral atmosphere. There are

Prompt enhancement of the Earth's outer radiation belt due to substorm electron injections

DOE PAGES

Tang, C. L.; Zhang, J. -C.; Reeves, G. D.; ...

2016-12-17

Here, we present multipoint simultaneous observations of the near-Earth magnetotail and outer radiation belt during the substorm electron injection event on 16 August 2013. Time History of Events and Macroscale Interactions during Substorms A in the near-Earth magnetotail observed flux-enhanced electrons of 300 keV during the magnetic field dipolarization. Geosynchronous orbit satellites also observed the intensive electron injections. Located in the outer radiation belt, RBSP-A observed enhancements of MeV electrons accompanied by substorm dipolarization. The phase space density (PSD) of MeV electrons at L* ~5.4 increased by 1 order of magnitude in 1 h, resulting in a local PSD peakmore » of MeV electrons, which was caused by the direct effect of substorm injections. We also detected an enhanced MeV electrons in the heart of the outer radiation belt within 2 h, which may be associated with intensive substorm electron injections and subsequent local acceleration by chorus waves. Multipoint observations have shown that substorm electron injections not only can be the external source of MeV electrons at the outer edge of the outer radiation belt (L* ~5.4) but also can provide the intensive seed populations in the outer radiation belt. These initial higher-energy electrons from injection can reach relativistic energy much faster. Furthermore, these observations also provide evidence that enhanced substorm electron injections can explain rapid enhancements of MeV electrons in the outer radiation belt.« less

Prompt enhancement of the Earth's outer radiation belt due to substorm electron injections

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

Tang, C. L.; Zhang, J. -C.; Reeves, G. D.

Here, we present multipoint simultaneous observations of the near-Earth magnetotail and outer radiation belt during the substorm electron injection event on 16 August 2013. Time History of Events and Macroscale Interactions during Substorms A in the near-Earth magnetotail observed flux-enhanced electrons of 300 keV during the magnetic field dipolarization. Geosynchronous orbit satellites also observed the intensive electron injections. Located in the outer radiation belt, RBSP-A observed enhancements of MeV electrons accompanied by substorm dipolarization. The phase space density (PSD) of MeV electrons at L* ~5.4 increased by 1 order of magnitude in 1 h, resulting in a local PSD peakmore » of MeV electrons, which was caused by the direct effect of substorm injections. We also detected an enhanced MeV electrons in the heart of the outer radiation belt within 2 h, which may be associated with intensive substorm electron injections and subsequent local acceleration by chorus waves. Multipoint observations have shown that substorm electron injections not only can be the external source of MeV electrons at the outer edge of the outer radiation belt (L* ~5.4) but also can provide the intensive seed populations in the outer radiation belt. These initial higher-energy electrons from injection can reach relativistic energy much faster. Furthermore, these observations also provide evidence that enhanced substorm electron injections can explain rapid enhancements of MeV electrons in the outer radiation belt.« less

High-Latitude Stratospheric Sensitivity to QBO Width in a Chemistry-Climate Model with Parameterized Ozone Chemistry

NASA Technical Reports Server (NTRS)

Hurwitz, M. M.; Braesicke, P.; Pyle, J. A.

2010-01-01

In a pair of idealized simulations with a simplified chemistry-climate model, the sensitivity of the wintertime Arctic stratosphere to variability in the width of the quasi-biennial oscillation (QBO) is assessed. The width of the QBO appears to have equal influence on the Arctic stratosphere as does the phase (i.e. the Holton-Tan mechanism). In the model, a wider QBO acts like a preferential shift toward the easterly phase of the QBO, where zonal winds at 60 N tend to be relatively weaker, while 50 hPa geopotential heights and polar ozone values tend to be higher.

Characterization of lunar ferromagnetic phases by the effective linewidth method

NASA Technical Reports Server (NTRS)

Patton, C. E.; Schmidt, H.

1978-01-01

The effective line-width technique, first developed to study the physics of microwave relaxation in ferrites, has been successfully applied to lunar matter. Effective line-width measurements have been made on two selected samples containing disperse spherical metallic iron particles below 40 microns in diam. The data were obtained for fields from 7 to 12 kOe and a temperature range 125 - 300 K. The effective line width was field-independent and temperature-independent at 650 - 750 Oe. The high-field tails of the ferromagnetic resonance absorption were highly Lorentzian. From the relatively large and temperature-independent high-field effective line widths, it appears that (1) the metallic iron phases in lunar soil are rather impure; (2) the impurities are passive, in that there is no evidence for a temperature peak process; and (3) these samples contain no appreciable magnetite.

Performance of large aperture tapered fiber phase conjugate mirror with high pulse energy and 1-kHz repetition rate.

PubMed

Zhao, Zhigang; Dong, Yantao; Pan, Sunqiang; Liu, Chong; Chen, Jun; Tong, Lixin; Gao, Qingsong; Tang, Chun

2012-01-16

A large aperture fused silica tapered fiber phase conjugate mirror is presented with a maximum 70% stimulated Brillouin scattering (SBS) reflectivity, which is obtained with 1 kHz repetition rate, 15 ns pulse width and 38 mJ input pulse energy. To the best of our knowledge, this is the highest SBS reflectivity ever reported by using optical fiber as a phase conjugate mirror for such high pulse repetition rate (1 kHz) and several tens of millijoule (mJ) input pulse energy. The influences of fiber end surface quality and pump pulse widths on SBS reflectivity are investigated experimentally. The results show that finer fiber end surface quality and longer input pulse widths are preferred for obtaining higher SBS reflectivity with higher input pulse energy. Double passing amplification experiments are also performed. 52 mJ pulse energy is achieved at 1 kHz repetition rate, with a reflected SBS pulse width of 1.5 ns and a M(2) factor of 2.3. The corresponding peak power reaches 34.6 MW. Obvious beam quality improvement is observed.

Disparity of spectral behavior of RR Tel and RX Pup in the UV

NASA Astrophysics Data System (ADS)

Sanad, M. R.

2010-07-01

The main aim of this study is to use archival low-dispersion spectra from the International Ultraviolet Explorer (IUE) in an attempt to follow up the spectral behavior of two symbiotic Mira systems RR Tel and RX Pup of the period from 1978-1995 and 1979-1989 for two systems respectively. We concentrated on studying N IV 1486 Å intercombination line, coming from the emission nebulae ( Bryan and Kwok, 1991; Muerset et al., 1991; Murset and Nussbaumer, 1994), by calculating the line fluxes and line widths of N IV 1486 Å. We found that there is a disparity of spectral variability for these physical parameters at different times for both systems. For RR Tel, both line fluxes and line widths are increasing with the phase, while for RX Pup, both line fluxes and line widths are decreasing with the phase. There is a relation between the parameters of this emission line (line flux, line width) and phase, which we attribute to the variations of temperature of the emission nebulae at different times, as a result of the activity of the hot component.

Modeling of Outer Radiation Belt Electron Scattering due to Spatial and Spectral Properties of ULF Waves

NASA Astrophysics Data System (ADS)

Tornquist, Mattias

The research presented in this thesis covers wave-particle interactions for relativistic (0.5-10 MeV) electrons in Earth's outer radiation belt (r = 3-7 RE, or L-shells: L = 3-7) interacting with magnetospheric Pc-5 (ULF) waves. This dissertation focuses on ideal models for short and long term electron energy and radial position scattering caused by interactions with ULF waves. We use test particle simulations to investigate these wave-particle interactions with ideal wave and magnetic dipole fields. We demonstrate that the wave-particle phase can cause various patterns in phase space trajectories, i.e. local acceleration, and that for a global electron population, for all initial conditions accounted for, has a negligible net energy scattering. Working with GSM polar coordinates, the relevant wave field components are EL, Ephi and Bz, where we find that the maximum energy scattering is 3-10 times more effective for Ephi compared to EL in a magnetic dipole field with a realistic dayside compression amplitude. We also evaluate electron interactions with two coexisting waves for a set of small frequency separations and phases, where it is confirmed that multi-resonant transport is possible for overlapping resonances in phase space when the Chirikov criterion is met (stochasticity parameter K = 1). The electron energy scattering enhances with decreasing frequency separation, i.e. increasing K, and is also dependent on the phases of the waves. The global acceleration is non-zero, can be onset in about 1 hour and last for > 4 hours. The adiabatic wave-particle interaction discussed up to this point can be regarded as short-term scattering ( tau ˜ hours ). When the physical problem extends to longer time scales (tau ˜ days ) the process ceases to be adiabatic due to the introduction of stochastic element in the system and becomes a diffusive process. We show that any mode in a broadband spectrum can contribute to the total diffusion rate for a particular drift frequency within the spectral band via dynamic phases. Each mode contributes maximally at a phase reset frequency fr = 2.63fk, where fk is the mode frequency. We experiment with electron diffusion due to interaction with wave broadband spectra in MLT sectors and find the phase reset effect being strongest when there is no azimuthal wave vector (msec = 0) within the sector. DLL rapidly coheres to the local PSD as the wave number increases and, for example, at msec = 1.00+/-0.25 the effect of phase resets is only 10-30% as strong as for msec = 0. Since phase resets depend on particle drift frequencies when MLT sectors are involved, a consequence is that DLL must adjust as a function of L-shell as well. For example, from the local PSD as the sole contributor to diffusion Schulz and Lanzerotte (1979) has shown that DLL ˜ L6 , but we prove that the function becomes DLL ˜ L5 with some variations due to fd and MLT sector width. The final part of this dissertation evaluates a pre storm commencement event on November 7, 2004, when Earth's magnetopause was struck by a high-speed solar wind with a mostly northward component of interplanetary magnetic field. We obtained a global MHD field simulated by the OpenGGC model for the interval 17:00-18:40 in universal time from NASA's Community Coordinated Modeling Center. Global distribution plots of the electric and magnetic field PSD reveal strong ULF waves spanning the whole dayside sector. There are distinct electric field modes at approximately 0.9, 2.3 and 3.7-6.3 mHz within the dayside sector, which we then used in test-particle simulations and the variance calculations in order to evaluate the diffusion coefficients. To ensure diffusion by sufficient stochasticity, we run the event by repeating the interval 10 times in series for a total duration of 12 hours. For the wave electric fields, the predicted diffusion coefficient due to local PSD matches the outcome from simulated electron scattering at 0.9 and 2.3 mHz. The diffusion due to the wider frequency band at 3.7-6.3 mHz does not fit the PSD profile alone, and requires phase resets in non-resonant modes within the spectrum to yield an agreement between the calculations and the simulations. Furthermore, only msec = 1 provides the correct solution. We have thus demonstrated the importance in including both the MLT sector width and wave number as additional significant factors apart from the local PSD in determining the diffusion coefficient for a realistic wave field. (Abstract shortened by UMI.).

Quantitative studies on inner interfaces in conical metal joints using hard x-ray inline phase contrast radiography

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

Zabler, S.; Rack, T.; Nelson, K.

2010-10-15

Quantitative investigation of micrometer and submicrometer gaps between joining metal surfaces is applied to conical plug-socket connections in dental titanium implants. Microgaps of widths well beyond the resolving power of industrial x-ray systems are imaged by synchrotron phase contrast radiography. Furthermore, by using an analytical model for the relatively simple sample geometry and applying it to numerical forward simulations of the optical Fresnel propagation, we show that quantitative measurements of the microgap width down to 0.1 {mu}m are possible. Image data recorded at the BAMline (BESSY-II light source, Germany) are presented, with the resolving power of the imaging system beingmore » 4 {mu}m in absorption mode and {approx}14 {mu}m in phase contrast mode (z{sub 2}=0.74 m). Thus, phase contrast radiography, combined with numerical forward simulations, is capable of measuring the widths of gaps that are two orders of magnitude thinner than the conventional detection limit.« less

Two-phase flow regimes in a horizontal microchannel with the height of 50 μm and width of 10 mm

NASA Astrophysics Data System (ADS)

Fina, V. P.; Ronshin, F. V.

2017-11-01

Two-phase flows of distilled deionized nanofiltered water and nitrogen gas in a microchannel with a height of 50 μm and a width of 10 mm have been investigated experimentally. The schlieren method has been used to determine main features of the two-phase flow in the microchannel. This method allows detecting the liquid film on the lower and upper walls of the microchannel as well as droplets of various shapes and sizes or vertical liquid bridges. Two-phase flow regimes have been observed, and their boundaries precisely determined using post-processing of the recordings. The following flow regimes have been distinguished: bubble, churn, jet, stratified and annular. Comparison of regime maps for channels of different widths has been carried out, and this parameter showed to have a significant impact on the boundaries between the regimes in microchannels of a height of less than 100 μm.

Dependence of optical phase modulation on anchoring strength of dielectric shield wall surfaces in small liquid crystal pixels

NASA Astrophysics Data System (ADS)

Isomae, Yoshitomo; Shibata, Yosei; Ishinabe, Takahiro; Fujikake, Hideo

2018-03-01

We demonstrated that the uniform phase modulation in a pixel can be realized by optimizing the anchoring strength on the walls and the wall width in the dielectric shield wall structure, which is the needed pixel structure for realizing a 1-µm-pitch optical phase modulator. The anchoring force degrades the uniformity of the phase modulation in ON-state pixels, but it also keeps liquid crystals from rotating against the leakage of an electric field. We clarified that the optimal wall width and anchoring strength are 250 nm and less than 10-4 J/m2, respectively.

AIS Spectra for Stressed and Unstressed Plant Communities in the Carolina Slate Belt

NASA Technical Reports Server (NTRS)

Wickland, D. E.

1985-01-01

Airborne imaging spectrometer (AIS) data were collected over a number of derelict heavy metal mine sites in the Carolina slate belt of North Carolina. A 32 channel (1156 to 1456 nm) data set was acquired in October, 1983 at the time of peak fall foliage display, and a 128 channel (1220 to 2420) data set was acquired near the end of the spring leaf flush in May, 1984. Spectral curves were extracted from the AIS data for differing ground cover types (e.g., pine forests, mixed deciduous forests, mine sites, and pastures). Variation in the width of an absorption feature located at approximately 1190 nm has been related to differences in forest type. Small differences in the location and shape of features in the near infrared plateau (1156 to 1300 nm) and the region 2000 to 2420 nm have yet to be evaluated. Because these variations were subtle, and because atmospheric effects were apparent in the data, high priority must be assigned to devising a means of removing atmospheric effects from AIS spectra.

Reducing death on the road: the effects of minimum safety standards, publicized crash tests, seat belts, and alcohol.

PubMed Central

Robertson, L S

1996-01-01

OBJECTIVES. Two phases of attempts to improve passenger car crash worthiness have occurred: minimum safety standards and publicized crash tests. This study evaluated these attempts, as well as changes in seat belt and alcohol use, in terms of their effect on occupant death and fatal crash rates. METHODS. Data on passenger car occupant fatalities and total involvement in fatal crashes, for 1975 through 1991, were obtained from the Fatal Accident Reporting System. Rates per mile were calculated through published sources on vehicle use by vehicle age. Regression estimates of effects of regulation, publicized crash tests, seat belt use and alcohol involvement were obtained. RESULTS. Substantial reductions in fatalities occurred in the vehicle model years from the late 1960s through most of the 1970s, when federal standards were applied. Some additional increments in reduced death rates, attributable to additional improved vehicle crashworthiness, occurred during the period of publicized crash tests. Increased seat belt use and reduced alcohol use also contributed significantly to reduced deaths. CONCLUSIONS. Minimum safety standards, crashworthiness improvements, seat belt use laws, and reduced alcohol use each contributed to a large reduction in passenger car occupant deaths. PMID:8561238

Empirical analysis of storm-time energetic electron enhancements

NASA Astrophysics Data System (ADS)

O'Brien, Thomas Paul, III

This Ph.D. thesis documents a program for studying the appearance of energetic electrons in the Earth's outer radiation belts that is associated with many geomagnetic storms. The dynamic evolution of the electron radiation belts is an outstanding empirical problem in both theoretical space physics and its applied sibling, space weather. The project emphasizes the development of empirical tools and their use in testing several theoretical models of the energization of the electron belts. First, I develop the Statistical Asynchronous Regression technique to provide proxy electron fluxes throughout the parts of the radiation belts explored by geosynchronous and GPS spacecraft. Next, I show that a theoretical adiabatic model can relate the local time asymmetry of the proxy geosynchronous fluxes to the asymmetry of the geomagnetic field. Then, I perform a superposed epoch analysis on the proxy fluxes at local noon to identify magnetospheric and interplanetary precursors of relativistic electron enhancements. Finally, I use statistical and neural network phase space analyses to determine the hourly evolution of flux at a virtual stationary monitor. The dynamic equation quantitatively identifies the importance of different drivers of the electron belts. This project provides empirical constraints on theoretical models of electron acceleration.

Scattering V-type asteroids during the giant planet instability: a step for Jupiter, a leap for basalt

NASA Astrophysics Data System (ADS)

Brasil, P. I. O.; Roig, F.; Nesvorný, D.; Carruba, V.

2017-06-01

V-type asteroids are a taxonomic class whose surface is associated with a basaltic composition. The only known source of V-type asteroids in the Main Asteroid Belt is (4) Vesta, which is located in the inner part of the Main Belt. However, many V-type asteroids cannot be dynamically linked to Vesta, in particular, those asteroids located in the middle and outer parts of the Main Belt. Previous works have failed to find mechanisms to transport V-type asteroids from the inner to the middle and outer belts. In this work, we propose a dynamical mechanism that could have acted on primordial asteroid families. We consider a model of the giant planet migration known as the jumping Jupiter model with five planets. Our study is focused on the period of 10 Myr that encompasses the instability phase of the giant planets. We show that, for different hypothetical Vesta-like paleo-families in the inner belt, the perturbations caused by the ice giant that is scattered into the asteroid belt before being ejected from the Solar system are able to scatter V-type asteroids to the middle and outer belts. Based on the orbital distribution of V-type candidates identified from the Sloan Digital Sky Survey and the VISTA Survey colours, we show that this mechanism is efficient enough provided that the hypothetical paleo-family originated from a 100 to 500 km crater excavated on the surface of (4) Vesta. This mechanism is able to explain the currently observed V-type asteroids in the middle and outer belts, with the exception of (1459) Magnya.

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

Borovsky, Joseph E; Cayton, Thomas E; Denton, Michael H

Electron flux measurements from 7 satellites in geosynchronous orbit from 1990-2007 are fit with relativistic bi-Maxwellians, yielding a number density n and temperature T description of the outer electron radiation belt. For 54.5 spacecraft years of measurements the median value ofn is 3.7x10-4 cm-3 and the median value ofT is 142 keY. General statistical properties of n, T, and the 1.1-1.5 MeV flux J are investigated, including local-time and solar-cycle dependencies. Using superposed-epoch analysis triggered on storm onset, the evolution of the outer electron radiation belt through high-speed-steam-driven storms is investigated. The number density decay during the calm before themore » storm is seen, relativistic-electron dropouts and recoveries from dropout are investigated, and the heating of the outer electron radiation belt during storms is examined. Using four different triggers (SSCs, southward-IMF CME sheaths, southward-IMF magnetic clouds, and minimum Dst), CME-driven storms are analyzed with superposed-epoch techniques. For CME-driven storms an absence of a density decay prior to storm onset is found, the compression of the outer electron radiation belt at time of SSC is analyzed, the number-density increase and temperature decrease during storm main phase is seen, and the increase in density and temperature during storm recovery phase is observed. Differences are found between the density-temperature and the flux descriptions, with more information for analysis being available in the density-temperature description.« less

THE ASTEROID BELT AS A RELIC FROM A CHAOTIC EARLY SOLAR SYSTEM

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

Izidoro, André; Raymond, Sean N.; Pierens, Arnaud

The orbital structure of the asteroid belt holds a record of the solar system’s dynamical history. The current belt only contains ∼10{sup −3} Earth masses yet the asteroids’ orbits are dynamically excited, with a large spread in eccentricity and inclination. In the context of models of terrestrial planet formation, the belt may have been excited by Jupiter’s orbital migration. The terrestrial planets can also be reproduced without invoking a migrating Jupiter; however, as it requires a severe mass deficit beyond Earth’s orbit, this model systematically under-excites the asteroid belt. Here we show that the orbits of the asteroids may havemore » been excited to their current state if Jupiter’s and Saturn’s early orbits were chaotic. Stochastic variations in the gas giants’ orbits cause resonances to continually jump across the main belt and excite the asteroids’ orbits on a timescale of tens of millions of years. While hydrodynamical simulations show that the gas giants were likely in mean motion resonance at the end of the gaseous disk phase, small perturbations could have driven them into a chaotic but stable state. The gas giants’ current orbits were achieved later, during an instability in the outer solar system. Although it is well known that the present-day solar system exhibits chaotic behavior, our results suggest that the early solar system may also have been chaotic.« less

JOVIAN EARLY BOMBARDMENT: PLANETESIMAL EROSION IN THE INNER ASTEROID BELT

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

Turrini, D.; Coradini, A.; Magni, G., E-mail: diego.turrini@ifsi-roma.inaf.it

The asteroid belt is an open window on the history of the solar system, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions (SFDs). In this work, we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of themore » primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depends on the SFD of the primordial planetesimals. If the asteroid belt was dominated by planetesimals less than 100 km in diameter, the primordial bombardment would have caused the erosion of bodies smaller than 200 km in diameter. If the asteroid belt was instead dominated by larger planetesimals, the bombardment would have resulted in the destruction of bodies as big as 500 km.« less

Statistics of the radiated field of a space-to-earth microwave power transfer system

NASA Technical Reports Server (NTRS)

Stevens, G. H.; Leininger, G.

1976-01-01

Statistics such as average power density pattern, variance of the power density pattern and variance of the beam pointing error are related to hardware parameters such as transmitter rms phase error and rms amplitude error. Also a limitation on spectral width of the phase reference for phase control was established. A 1 km diameter transmitter appears feasible provided the total rms insertion phase errors of the phase control modules does not exceed 10 deg, amplitude errors do not exceed 10% rms, and the phase reference spectral width does not exceed approximately 3 kHz. With these conditions the expected radiation pattern is virtually the same as the error free pattern, and the rms beam pointing error would be insignificant (approximately 10 meters).

Simulating the heterogeneity in braided channel belt deposits: 2. Examples of results and comparison to natural deposits

NASA Astrophysics Data System (ADS)

Guin, Arijit; Ramanathan, Ramya; Ritzi, Robert W.; Dominic, David F.; Lunt, Ian A.; Scheibe, Timothy D.; Freedman, Vicky L.

2010-04-01

In part 1 of this paper (Ramanathan et al., 2010b) we presented a methodology and a code for modeling the hierarchical sedimentary architecture in braided channel belt deposits. Here in part 2, the code was used to create a digital model of this architecture and the corresponding spatial distribution of permeability. The simulated architecture was compared to the real stratal architecture observed in an abandoned channel belt. The comparisons included assessments of similarity which were both qualitative and quantitative. The qualitative comparisons show that the geometries of unit types within the synthetic deposits are generally consistent with field observations. The unit types in the synthetic deposits would generally be recognized as representing their counterparts in nature, including cross stratasets, lobate and scroll bar deposits, and channel fills. Furthermore, the synthetic deposits have a hierarchical spatial relationship among these units consistent with observations from field exposures and geophysical images. In quantitative comparisons the proportions and the length, width, and height of unit types at different scales, across all levels of the stratal hierarchy, compare well between the synthetic and the natural deposits. A number of important attributes of the synthetic channel belt deposits are shown to be influenced by more than one level within the hierarchy of stratal architecture. First, the high-permeability open-framework gravels connected across all levels and thus formed preferential flow pathways; open-framework gravels are known to form preferential flow pathways in natural channel belt deposits. The nature of a connected cluster changed across different levels of the stratal hierarchy, and as a result of the geologic structure, the connectivity occurs at proportions of open-framework gravels below the theoretical percolation threshold for random infinite media. Second, when the channel belt model was populated with permeability distributions by lowest-level unit type, the composite permeability semivariogram contained structures that were identifiable at more than one scale, and each of these structures could be directly linked to unit types of different scales existing at different levels within the hierarchy of strata. These collective results are encouraging with respect to our goal that this model be relevant for testing ideas in future research on flow and transport in aquifers and reservoirs with multiscale heterogeneity.

Characterizing filaments in regions of high-mass star formation: High-resolution submilimeter imaging of the massive star-forming complex NGC 6334 with ArTéMiS

NASA Astrophysics Data System (ADS)

André, Ph.; Revéret, V.; Könyves, V.; Arzoumanian, D.; Tigé, J.; Gallais, P.; Roussel, H.; Le Pennec, J.; Rodriguez, L.; Doumayrou, E.; Dubreuil, D.; Lortholary, M.; Martignac, J.; Talvard, M.; Delisle, C.; Visticot, F.; Dumaye, L.; De Breuck, C.; Shimajiri, Y.; Motte, F.; Bontemps, S.; Hennemann, M.; Zavagno, A.; Russeil, D.; Schneider, N.; Palmeirim, P.; Peretto, N.; Hill, T.; Minier, V.; Roy, A.; Rygl, K. L. J.

2016-07-01

Context. Herschel observations of nearby molecular clouds suggest that interstellar filaments and prestellar cores represent two fundamental steps in the star formation process. The observations support a picture of low-mass star formation according to which filaments of ~0.1 pc width form first in the cold interstellar medium, probably as a result of large-scale compression of interstellar matter by supersonic turbulent flows, and then prestellar cores arise from gravitational fragmentation of the densest filaments. Whether this scenario also applies to regions of high-mass star formation is an open question, in part because the resolution of Herschel is insufficient to resolve the inner width of filaments in the nearest regions of massive star formation. Aims: In an effort to characterize the inner width of filaments in high-mass star-forming regions, we imaged the central part of the NGC 6334 complex at a resolution higher by a factor of >3 than Herschel at 350 μm. Methods: We used the large-format bolometer camera ArTéMiS on the APEX telescope and combined the high-resolution ArTéMiS data at 350 μm with Herschel/HOBYS data at 70-500 μm to ensure good sensitivity to a broad range of spatial scales. This allowed us to study the structure of the main narrow filament of the complex with a resolution of 8″ or <0.07 pc at d ~ 1.7 kpc. Results: Our study confirms that this filament is a very dense, massive linear structure with a line mass ranging from ~500 M⊙/pc to ~2000 M⊙/pc over nearly 10 pc. It also demonstrates for the first time that its inner width remains as narrow as W ~ 0.15 ± 0.05 pc all along the filament length, within a factor of <2 of the characteristic 0.1 pc value found with Herschel for lower-mass filaments in the Gould Belt. Conclusions: While it is not completely clear whether the NGC 6334 filament will form massive stars in the future, it is two to three orders of magnitude denser than the majority of filaments observed in Gould Belt clouds, and has a very similar inner width. This points to a common physical mechanism for setting the filament width and suggests that some important structural properties of nearby clouds also hold in high-mass star-forming regions. This publication is based on data acquired with the Atacama Pathfinder Experiment (APEX) in ESO program 091.C-0870. APEX is a collaboration between the Max-Planck-Institut für Radioastronomie, the European Southern Observatory, and the Onsala Space Observatory.The final ArTéMiS+SPIRE 350 μm map (Fig. 1b) is available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A54

Revisiting NMR composite pulses for broadband 2H excitation

PubMed Central

Shen, Ming; Roopchand, Rabia; Mananga, Eugene S.; Amoureux, Jean-Paul; Chen, Qun; Boutis, Gregory S.; Hu, Bingwen

2014-01-01

Quadrupolar echo NMR spectroscopy of static solids often requires RF excitation that covers spectral widths exceeding 100 kHz, which is difficult to obtain due to instrumental limitations. In this work we revisit four well-known composite pulses (COM-I, II, III and IV) for broadband excitation in deuterium quadrupolar echo spectroscopy. These composite pulses are combined with several phase cycling schemes that were previously shown to decrease finite pulse width distortions in deuterium solid-echo experiments performed with two single pulses. The simulations and experiments show that COM-II and IV composite pulses combined with an 8-step phase cycling aid in achieving broadband excitation with limited pulse width distortions. PMID:25583576

Automatic alternative phase-shift mask CAD layout tool for gate shrinkage of embedded DRAM in logic below 0.18 μm

NASA Astrophysics Data System (ADS)

Ohnuma, Hidetoshi; Kawahira, Hiroichi

1998-09-01

An automatic alternative phase shift mask (PSM) pattern layout tool has been newly developed. This tool is dedicated for embedded DRAM in logic device to shrink gate line width with improving line width controllability in lithography process with a design rule below 0.18 micrometers by the KrF excimer laser exposure. The tool can crete Levenson type PSM used being coupled with a binary mask adopting a double exposure method for positive photo resist. By using graphs, this tool automatically creates alternative PSM patterns. Moreover, it does not give any phase conflicts. By adopting it to actual embedded DRAM in logic cells, we have provided 0.16 micrometers gate resist patterns at both random logic and DRAM areas. The patterns were fabricated using two masks with the double exposure method. Gate line width has been well controlled under a practical exposure-focus window.

Effects of Drift-Shell Splitting by Chorus Waves on Radiation Belt Electrons

NASA Astrophysics Data System (ADS)

Chan, A. A.; Zheng, L.; O'Brien, T. P., III; Tu, W.; Cunningham, G.; Elkington, S. R.; Albert, J.

2015-12-01

Drift shell splitting in the radiation belts breaks all three adiabatic invariants of charged particle motion via pitch angle scattering, and produces new diffusion terms that fully populate the diffusion tensor in the Fokker-Planck equation. Based on the stochastic differential equation method, the Radbelt Electron Model (REM) simulation code allows us to solve such a fully three-dimensional Fokker-Planck equation, and to elucidate the sources and transport mechanisms behind the phase space density variations. REM has been used to perform simulations with an empirical initial phase space density followed by a seed electron injection, with a Tsyganenko 1989 magnetic field model, and with chorus wave and ULF wave diffusion models. Our simulation results show that adding drift shell splitting changes the phase space location of the source to smaller L shells, which typically reduces local electron energization (compared to neglecting drift-shell splitting effects). Simulation results with and without drift-shell splitting effects are compared with Van Allen Probe measurements.

Resolved Millimeter Observations of the HR 8799 Debris Disk

NASA Astrophysics Data System (ADS)

Wilner, David J.; MacGregor, Meredith A.; Andrews, Sean M.; Hughes, A. Meredith; Matthews, Brenda; Su, Kate

2018-03-01

We present 1.3 mm observations of the debris disk surrounding the HR 8799 multi-planet system from the Submillimeter Array to complement archival ALMA observations that spatially filtered away the bulk of the emission. The image morphology at 3.″8 (150 au) resolution indicates an optically thin circumstellar belt, which we associate with a population of dust-producing planetesimals within the debris disk. The interferometric visibilities are fit well by an axisymmetric radial power-law model characterized by a broad width, ΔR/R ≳ 1. The belt inclination and orientation parameters are consistent with the planet orbital parameters within the mutual uncertainties. The models constrain the radial location of the inner edge of the belt to {R}in}={104}-12+8 au. In a simple scenario where the chaotic zone of the outermost planet b truncates the planetesimal distribution, this inner edge location translates into a constraint on the planet b mass of {M}pl}={5.8}-3.1+7.9 M Jup. This mass estimate is consistent with infrared observations of the planet luminosity and standard hot-start evolutionary models, with the uncertainties allowing for a range of initial conditions. We also present new 9 mm observations of the debris disk from the Very Large Array and determine a millimeter spectral index of 2.41 ± 0.17. This value is typical of debris disks and indicates a power-law index of the grain size distribution q = 3.27 ± 0.10, close to predictions for a classical collisional cascade.

Tectonic evolution of kid metamorphic complex and the recognition of Najd fault system in South East Sinai, Egypt

NASA Astrophysics Data System (ADS)

Sultan, Yasser M.; El-Shafei, Mohamed K.; Arnous, Mohamed O.

2017-03-01

A low-to medium-grade metamorphic belt of a volcano-sedimentary succession occurs in the eastern side of South Sinai as a part of the northernmost extension of the Arabian-Nubian Shield in Egypt. The belt is known as the Kid metamorphic complex. It is considered as one of the major belt among the other exposed metamorphic belts in South Sinai. Here, we detect and investigate the signature of the Najd Fault system in South Sinai based on detailed structural analysis in field and digital image processing. The enhanced satellite image and the geo-spatial distributions confirm that the Kid belt is essentially composed of nine Precambrian units. Field relations and geometrical analysis of the measured structural data revealed that the study area underwent four successive deformational phases (D1-D4). D1 is an upright tight to isoclinal large-scale folds that caused few F1 small-scale folds and a steeply dipping S1 axial plane foliation. The second deformational event D2 produced dominant of sub-horizontal S2 foliation planes accompanied with recumbent isoclinal folds and NW-SE trending L2 lineations. The main sense during D2 was top-to-the-NW with local reversals to the SE. The third folding generations F3 is recorded as axial plane S3-surfaces and is characterized by open concentric folding that overprinting both F1 and F2 folds and has a flexural-slip mechanism. F3 fold hinges plunge to the west-northwest or east-southeast indicate north-northeast-south-southwest shortening during D3. The fourth deformational event D4 is characterized by NE plunging open concentric folding overprint the pre-existing fold generations and formed under flexural slip mechanism reflecting coaxial deformation and indicating change in the stress regime as a result of the change in shortening from NE-SW to NW-SE. This phase is probably accompanied with the final assembly of east and west Gondwana. The dextral NW-SE shear zone that bounded the southwestern portion of the metamorphic belt is probably related to reactivation of the Najd fault system during Oligo-Miocene in South Sinai.

Geometry and kinematics of Majiatan Fold-and-thrust Belt, Western Ordos Basin: implication for Tectonic Evolution of North-South Tectonic Belt

NASA Astrophysics Data System (ADS)

He, D.

2017-12-01

The Helan-Chuandian North-South Tectonic Belt crossed the central Chinese mainland. It is a boundary of geological, geophysical, and geographic system of Chinese continent tectonics from shallow to deep, and a key zone for tectonic and geomorphologic inversion during Mesozoic to Cenozoic. It is superimposed by the southeastward and northeastward propagation of Qinghai-Tibet Plateau in late Cenozoic. It is thus the critical division for West and East China since Mesozoic. The Majiatan fold-and-thrust belt (MFTB), locating at the central part of HCNSTB and the western margin of Ordos Basin, is formed by the tectonic evolution of the Helan-Liupanshan Mountains. Based on the newly-acquired high-resolution seismic profiles, deep boreholes, and surface geology, the paper discusses the geometry, kinematics, and geodynamic evolution of MFTB. With the Upper Carboniferous coal measures and the pre-Sinian ductile zone as the detachments, MFTB is a multi-level detached thrust system. The thrusting was mainly during latest Jurassic to Late Cretaceous, breaking-forward in the foreland, and resulting in a shortening rate of 25-29%. By structural restoration, this area underwent extension in Middle Proterozoic to Paleozoic, which can be divided into three phases of rifting such as Middle to Late Proterozoic, Cambiran to Ordovician, and Caboniferous to early Permian. It underwent compression since Late Triassic, including such periods as Latest Triassic, Late Jurassic to early Cretaceous, Late Cretaceous to early Paleogene, and Pliocene to Quaternary, with the largest shortening around Late Jurassic to early Cretaceous period (i.e. the mid-Yanshanian movement by the local name). However, trans-extension since Eocene around the Ordos Basin got rise to the formation the Yingchuan, Hetao, and Weihe grabens. It is concluded that MFTB is the leading edge of the intra-continental Helan orogenic belt, and formed by multi-phase breaking-forward thrusting during Late Jurassic to Cretaceous. During Cenozoic, MFTB is moderately modified by the northeastward compression due to the NE propagation of Qinghai-Tibet Plateau, and distinctly superimposed by the Yingchuan half-graben. North-South Tectonic Belt underwent a full cycle from extension during Middle Proterozoic to Paleozoic to compression since late Triassic.

A three-coordinate system (ecliptic, galactic, ISMF) spectral analysis of heliospheric ENA emissions using CASSINI/INCA measurements

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

Dialynas, K.; Krimigis, S. M.; Mitchell, D. G.

2013-11-20

In the present study, we use all-sky energy-resolved energetic neutral atom (ENA) maps obtained by the Ion and Neutral CAmera (INCA) instrument on board Cassini that correspond to the time period from 2003 to 2009, in four discrete energy passbands (∼5.4 to ∼55 keV), to investigate the geometrical characteristics of the belt (a broad band of emission in the sky). The heliospheric ENA emissions are mapped in three different coordinate systems (ecliptic, Galactic, and interstellar magnetic field (ISMF)), and spectral analyses are performed to further examine the belt's possible energy dependence. Our conclusions are summarized as follows: (1) the highmore » flux ENA belt identified in the energy range of 8-42 keV is moderately well organized in Galactic coordinates, as the ENA minima appear in the vicinity of the north and south Galactic poles; (2) using minimization criteria ( B · R ∼ 0), the deviation of the ENA emissions from the equator is effectively minimized in a rotated frame, which we interpret as ISMF, where its north pole points toward 190° ecliptic longitude and 15° ecliptic latitude; (3) ENA spectra show a power-law form in energy that can be fitted with a single function presenting higher spectral slopes in the belt region and lower outside (3.4 < γ < 4.4); (4) the spectra are almost indistinguishable between the tail and the nose regions, i.e., no noticeable asymmetry is observed; (5) the consistency of the ENA distributions as a function of latitude among the different INCA channels indicates that the morphology of the belt (peak, width, and structure) is nearly energy independent from 8 keV to 30 keV (minor deviations start to appear at >35 keV); and (6) in the low count rate regions, the long-term ENA count rate profiles do not match the measured cosmic ray profiles, indicating that even the minimum ENA emissions detected by INCA are foreground ENAs.« less

Kink-style detachment folding in Bachu fold belt of central Tarim Basin, China: geometry and seismic interpretation

NASA Astrophysics Data System (ADS)

Bo, Zhang; Jinjiang, Zhang; Shuyu, Yan; Jiang, Liu; Jinhai, Zhang; Zhongpei, Zhang

2010-05-01

The phenomenon of Kink banding is well known throughout the engineering and geophysical sciences. Associated with layered structures compressed in a layer-parallel direction, it arises for example in stratified geological systems under tectonic compression. Our work documented it is also possible to develop super large-scale kink-bands in sedimentary sequences. We interpret the Bachu fold uplift belt of the central Tarim basin in western China to be composed of detachment folds flanked by megascopic-scale kink-bands. Those previous principal fold models for the Bachu uplift belt incorporated components of large-scale thrust faulting, such as the imbricate fault-related fold model and the high-angle, reverse-faulted detachment fold model. Based on our observations in the outcrops and on the two-dimension seismic profiles, we interpret that first-order structures in the region are kink-band style detachment folds to accommodate regional shortening, and thrust faulting can be a second-order deformation style occurring on the limb of the detachment folds or at the cores of some folds to accommodate the further strain of these folds. The belt mainly consists of detachment folds overlying a ductile decollement layer. The crests of the detachment folds are bounded by large-scale kink-bands, which are zones of angularly folded strata. These low-signal-tonoise, low-reflectivity zones observed on seismic profiles across the Bachu belt are poorly imaged sections, which resulted from steeply dipping bedding in the kink-bands. The substantial width (beyond 200m) of these low-reflectivity zones, their sub-parallel edges in cross section, and their orientations at a high angle to layering between 50 and 60 degrees, as well as their conjugate geometry, support a kink-band interpretation. The kink-band interpretation model is based on the Maximum Effective Moment Criteria for continuous deformation, rather than Mohr-Column Criteria for brittle fracture. Seismic modeling is done to identify the characteristics and natures of seismic waves within the kink-band and its fold structure, which supplies the further evidences for the kink-band interpretation in the region.

Geophysical Evidence for the Tectonic Evolution of the Inverted Belt-Purcell Basin, Northwestern Montana

NASA Astrophysics Data System (ADS)

Rutherford, B. S.; Speece, M. A.; Constenius, K. N.

2015-12-01

The geometry of the Precambrian Belt-Purcell basin and subsequent allochthon, that dominates the geology of northwestern Montana, played a critical role in the development of compressional structures during orogenesis and their ensuing reactivation during the later phase of extensional collapse. Five reprocessed seismic reflection profiles provide images in the Swan Range and adjacent valleys that we have correlated to published seismic data north into Canada. Reflections from syndepositional sills encased within Lower Belt rocks offer clues to the configuration of the basin prior to its tectonic inversion. Thick basinal facies of the Lewis salient are contrasted by thin shelfal facies found in hanging wall rocks of frontal Belt carrying thrusts south of the salient. The along strike change in hanging wall rocks reflects the original configuration of the Belt basin margin. Rocks of the Lewis salient were deposited in an embayment on the northeastern margin of the Belt basin. Shelfal accumlations of the embayment comprise an autochthonous wedge that has remained in the footwall of the Lewis thrust system. South of the embayment and related salient, nearly the entire Belt basin was detached from pre-Belt crystalline rocks and inverted at the latitude of the Sawtooth Range. Deeply exhumed Phanerozoic rocks of the Sawtooth Range are a direct consequence of the thin wedge geometry of the detached basin south of the Lewis salient that required growth of a substantial orogenic wedge to obtain critical taper values. We offer an alternate interpretation of a >10 km high, west facing décollement ramp that coincides with the Belt-Purcell basin margin. Previous interpretations in Montana have inferred the location of the basin margin ramp to approximate the trace of the Purcell Anticlinorium. Seismic data and cross-section balancing suggest the Rocky Mountain Trench as a more accurate location. Based on our proposed position of the basin margin the Belt-Purcell allocthon requires insignificant rotation during thrust emplacement which is in agreement with published interpretations of paleomagnetic data. We suggest small (<5°) clockwise rotation is due to an increase in extensional slip from the international border south to the Flathead Valley as opposed to an increase in compressional shortening to the north.The geometry of the Precambrian Belt-Purcell basin and subsequent allochthon, that dominates the geology of northwestern Montana, played a critical role in the development of compressional structures during orogenesis and their ensuing reactivation during the later phase of extensional collapse. Five reprocessed seismic reflection profiles provide images in the Swan Range and adjacent valleys that we have correlated to published seismic data north into Canada. Reflections from syndepositional sills encased within Lower Belt rocks offer clues to the configuration of the basin prior to its tectonic inversion. Thick basinal facies of the Lewis salient are contrasted by thin shelfal facies found in hanging wall rocks of frontal Belt carrying thrusts south of the salient. The along strike change in hanging wall rocks reflects the original configuration of the Belt basin margin. Rocks of the Lewis salient were deposited in an embayment on the northeastern margin of the Belt basin. Shelfal accumlations of the embayment comprise an autochthonous wedge that has remained in the footwall of the Lewis thrust system. South of the embayment and related salient, nearly the entire Belt basin was detached from pre-Belt crystalline rocks and inverted at the latitude of the Sawtooth Range. Deeply exhumed Phanerozoic rocks of the Sawtooth Range are a direct consequence of the thin wedge geometry of the detached basin south of the Lewis salient that required growth of a substantial orogenic wedge to obtain critical taper values. We offer an alternate interpretation of a >10 km high, west facing décollement ramp that coincides with the Belt-Purcell basin margin. Previous interpretations in Montana have inferred the location of the basin margin ramp to approximate the trace of the Purcell Anticlinorium. Seismic data and cross-section balancing suggest the Rocky Mountain Trench as a more accurate location. Based on our proposed position of the basin margin the Belt-Purcell allocthon requires insignificant rotation during thrust emplacement which is in agreement with published interpretations of paleomagnetic data. We suggest small (<5°) clockwise rotation is due to an increase in extensional slip from the international border south to the Flathead Valley as opposed to an increase in compressional shortening to the north.

Prediction and Optimization of Phase Transformation Region After Spot Continual Induction Hardening Process Using Response Surface Method

NASA Astrophysics Data System (ADS)

Qin, Xunpeng; Gao, Kai; Zhu, Zhenhua; Chen, Xuliang; Wang, Zhou

2017-09-01

The spot continual induction hardening (SCIH) process, which is a modified induction hardening, can be assembled to a five-axis cooperating computer numerical control machine tool to strengthen more than one small area or relatively large area on complicated component surface. In this study, a response surface method was presented to optimize phase transformation region after the SCIH process. The effects of five process parameters including feed velocity, input power, gap, curvature and flow rate on temperature, microstructure, microhardness and phase transformation geometry were investigated. Central composition design, a second-order response surface design, was employed to systematically estimate the empirical models of temperature and phase transformation geometry. The analysis results indicated that feed velocity has a dominant effect on the uniformity of microstructure and microhardness, domain size, oxidized track width, phase transformation width and height in the SCIH process while curvature has the largest effect on center temperature in the design space. The optimum operating conditions with 0.817, 0.845 and 0.773 of desirability values are expected to be able to minimize ratio (tempering region) and maximize phase transformation width for concave, flat and convex surface workpieces, respectively. The verification result indicated that the process parameters obtained by the model were reliable.

Quantification of the Precipitation Loss of Radiation Belt Electrons Observed by SAMPEX

NASA Astrophysics Data System (ADS)

Tu, W.; Selesnick, R. S.; Li, X.; Looper, M. D.

2009-12-01

Based on SAMPEX/PET observations, the rates and the spatial and temporal variations of electron loss to the atmosphere in the Earth’s radiation belt were quantified using a Drift-Diffusion model that includes the effects of azimuthal drifts and pitch angle diffusion. The measured electrons detected by SAMPEX can be distinguished as trapped, quasi-trapped (in the drift loss cone), and precipitating (in the bounce loss cone). The Drift-Diffusion model simulates the low-altitude electron distribution from SAMPEX. After fitting the model results to the data, the magnitudes and variations of the electron lifetime can be quantitatively determined based on the optimum model parameter values. Three magnetic storms of different types of magnitude were selected to estimate the various loss rates of ~0.5 to 3 MeV electrons during different phases of the storm and at L shells ranging from L=3.5 to L=6.5 (L represents the radial distance in the equatorial plane under a dipole field approximation). They are a small storm and a moderate storm in the current solar minimum and an intense storm right after the previous solar maximum. Model results for the three individual events showed that fast precipitation losses of energetic radiation belt electrons, as short as hours, persistently occurred in the storm main phases and with more efficient loss at higher energies, over wide range of L regions and over all the SAMPEX covered local times. In addition to this newly discovered common feature of the main phase electron lifetimes for all the storm events and at all L locations, some other properties of the electron loss rates that vary with time or locations, were also estimated and discussed. This method combining model with the low-altitude observations provides direct quantification of the electron loss rate, a prerequisite for any comprehensive modeling of the radiation belt electron dynamics.

Morphologic evolution of the Central Andes of Peru

NASA Astrophysics Data System (ADS)

Gonzalez, Laura; Pfiffner, O. Adrian

2012-01-01

In this paper, we analyze the morphology of the Andes of Peru and its evolution based on the geometry of river channels, their bedrock profiles, stream gradient indices and the relation between thrust faults and morphology. The rivers of the Pacific Basin incised Mesozoic sediments of the Marañon thrust belt, Cenozoic volcanics and the granitic rocks of the Coastal Batholith. They are mainly bedrock channels with convex upward shapes and show signs of active ongoing incision. The changes in lithology do not correlate with breaks in slope of the channels (or knick points) such that the high gradient indices (K) with values between 2,000-3,000 and higher than 3,000 suggest that incision is controlled by tectonic activity. Our analysis reveals that many of the ranges of the Western Cordillera were uplifted to the actual elevations where peaks reach to 6,000 m above sea level by thrusting along steeply dipping faults. We correlate this uplift with the Quechua Phase of Neogene age documented for the Subandean thrust belt. The rivers of the Amazonas Basin have steep slopes and high gradient indices of 2,000-3,000 and locally more than 3,000 in those segments where the rivers flow over the crystalline basement of the Eastern Cordillera affected by vertical faulting. Gradient indices decrease to 1,000-2,000 within the east-vergent thrust belt of the Subandean Zone. Here a correlation between breaks in river channel slopes and location of thrust faults can be established, suggesting that the young, Quechua Phase thrust faults of the Subandean thrust belt, which involve Neogene sediments, influenced the channel geometry. In the eastern lowlands, these rivers become meandering and flow parallel to anticlines that formed in the hanging wall of Quechua Phase thrust faults, suggesting that the river courses were actively displaced outward into the foreland.

An image of the Columbia Plateau from inversion of high-resolution seismic data

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

Lutter, W.J.; Catchings, R.D.; Jarchow, C.M.

1994-08-01

The authors use a method of traveltime inversion of high-resolution seismic data to provide the first reliable images of internal details of the Columbia River Basalt Group (CRBG), the subsurface basalt/sediment interface, and the deeper sediment/basement interface. Velocity structure within the basalts, delineated on the order of 1 km horizontally and 0.2 km vertically, is constrained to within [plus minus]0.1 km/s for most of the seismic profile. Over 5,000 observed traveltimes fit their model with an rms error of 0.018 s. The maximum depth of penetration of the basalt diving waves (truncated by underlying low-velocity sediments) provides a reliable estimatemore » of the depth to the base of the basalt, which agrees with well-log measurements to within 0.05 km (165 ft). The authors use image blurring, calculated from the resolution matrix, to estimate the aspect ratio of images velocity anomaly widths to true widths for velocity features within the basalt. From their calculations of image blurring, they interpret low velocity zones (LVZ) within the basalts at Boylston Mountain and the Whiskey Dick anticline to have widths of 4.5 and 3 km, respectively, within the upper 1.5 km of the model. At greater depth, the widths of these imaged LVZs thin to approximately 2 km or less. They interpret these linear, subparallel, low-velocity zones imaged adjacent to anticlines of the Yakima Fold Belt to be brecciated fault zones. These fault zones dip to the south at angles between 15 to 45 degrees.« less

On the source location of radiation belt relativistic electrons

NASA Astrophysics Data System (ADS)

Selesnick, R. S.; Blake, J. B.

2000-02-01

Observations from the High Sensitivity Telescope (HIST) on Polar made around Janurary and May 1998 are used to constrain the source location of outer radiation belt relativistic electrons. Phase space densities calculated as a function of the three adiabatic invariants show positive radial gradients for L<4, suggestive of no source in that region. In particular, the peak intensity near L=3 of a large enhancement beginning on May 4, 1998, appears to have been formed by inward transport over a period of several days. For L>4, peaks in the radial dependence of the phase space density are suggestive of a local electron source that may be nonadiabatic acceleration or pitch angle scattering. However, discrepancies in the results obtained with different magnetic field models and at different local times make this a tentative conclusion.

Mesozoic strike-slip movement of the Dunhua-Mishan Fault Zone in NE China: A response to oceanic plate subduction

NASA Astrophysics Data System (ADS)

Liu, Cheng; Zhu, Guang; Zhang, Shuai; Gu, Chengchuan; Li, Yunjian; Su, Nan; Xiao, Shiye

2018-01-01

The NE-striking Dunhua-Mishan Fault Zone (DMFZ) is one of two branches of the continental-scale sinistral Tan-Lu Fault Zone in NE China. The field data presented here indicate that the ca. 1000 km long DMFZ records two phases of sinistral faulting. The structures produced by these two phases of faulting include NE-SW-striking ductile shear belts and brittle faults, respectively. Mylonite-hosted microstructures and quartz c-axis fabrics suggest deformation temperatures of 450 °C-500 °C for the ductile shear belts. Combining new zircon U-Pb dates for 14 igneous rock samples analyzed during this study with the geology of this region indicates these shear belts formed during the earliest Early Cretaceous. This phase of sinistral displacement represents the initial formation of the DMFZ in response to the northward propagation of the Tan-Lu Fault Zone into NE China. A phase of Early Cretaceous rifting was followed by a second phase of sinistral faulting at 102-96 Ma, as evidenced by our new U-Pb ages for associated igneous rocks. Combining our new data with the results of previous research indicates that the DFMZ records a four-stage Cretaceous evolutionary history, where initial sinistral faulting at the beginning of the Early Cretaceous gave way to rifting during the rest of the Early Cretaceous. This was followed by a second phase of sinistral faulting at the beginning of the Late Cretaceous and a second phase of local rifting during the rest of the Late Cretaceous. The Cretaceous evolution of the DMFZ records the synchronous tectonic evolution of the NE China continent bordering the Pacific Ocean. Two phases of regional N-S compression generated the two phases of sinistral faulting within the DMFZ, whereas two-stage regional extension generated the two phases of rifting. The two compressive events were the result of the rapid low-angle subduction of the Izanagi and Pacific plates, whereas the two-stage extension was caused by the roll-back of these respective plates. The final closure of the Mongol-Okhotsk Ocean at the beginning of the Early Cretaceous intensified the synchronous compression in NE China, causing the northward propagation of the Tan-Lu Fault Zone.

Analysis of a non-storm time enhancement in outer belt electrons

NASA Astrophysics Data System (ADS)

Schiller, Q.; Li, X.; Godinez, H. C.; Sarris, T. E.; Tu, W.; Malaspina, D.; Turner, D. L.; Blake, J. B.; Koller, J.

2014-12-01

A high-speed solar wind stream impacted Earth's magnetosphere on January 13th, 2013, and is associated with a large enhancement (>2.5 orders) of outer radiation belt electron fluxes despite a small Dst signature (-30 nT). Fortunately, the outer belt was well sampled by a variety of missions during the event, including the Van Allen Probes, THEMIS, and the Colorado Student Space Weather Experiment (CSSWE). In-situ flux and phase space density observations are used from MagEIS (Magnetic Electron Ion Spectrometer) onboard the Van Allen Probes, REPTile (Relativistic Electron and Proton Telescope integrated little experiment) onboard CSSWE, and SST onboard THEMIS. The observations show a rapid increase in 100's keV electron fluxes, followed by a more gradual enhancement of the MeV energies. The 100's keV enhancement is associated with a substorm injection, and the futher energization to MeV energies is associated with wave activity as measured by the Van Allen Probes and THEMIS. Furthermore, the phase space density radial profiles show an acceleration region occurring between 5

A Linear Model of Phase-Dependent Power Correlations in Neuronal Oscillations

PubMed Central

Eriksson, David; Vicente, Raul; Schmidt, Kerstin

2011-01-01

Recently, it has been suggested that effective interactions between two neuronal populations are supported by the phase difference between the oscillations in these two populations, a hypothesis referred to as “communication through coherence” (CTC). Experimental work quantified effective interactions by means of the power correlations between the two populations, where power was calculated on the local field potential and/or multi-unit activity. Here, we present a linear model of interacting oscillators that accounts for the phase dependency of the power correlation between the two populations and that can be used as a reference for detecting non-linearities such as gain control. In the experimental analysis, trials were sorted according to the coupled phase difference of the oscillators while the putative interaction between oscillations was taking place. Taking advantage of the modeling, we further studied the dependency of the power correlation on the uncoupled phase difference, connection strength, and topology. Since the uncoupled phase difference, i.e., the phase relation before the effective interaction, is the causal variable in the CTC hypothesis we also describe how power correlations depend on that variable. For uni-directional connectivity we observe that the width of the uncoupled phase dependency is broader than for the coupled phase. Furthermore, the analytical results show that the characteristics of the phase dependency change when a bidirectional connection is assumed. The width of the phase dependency indicates which oscillation frequencies are optimal for a given connection delay distribution. We propose that a certain width enables a stimulus-contrast dependent extent of effective long-range lateral connections. PMID:21808618

Hierarchical sinuous-antenna phased array for millimeter wavelengths

NASA Astrophysics Data System (ADS)

Cukierman, Ari; Lee, Adrian T.; Raum, Christopher; Suzuki, Aritoki; Westbrook, Benjamin

2018-03-01

We present the design, fabrication, and measured performance of a hierarchical sinuous-antenna phased array coupled to superconducting transition-edge-sensor (TES) bolometers for millimeter wavelengths. The architecture allows for dual-polarization wideband sensitivity with a beam width that is approximately frequency-independent. We report on measurements of a prototype device, which uses three levels of triangular phased arrays to synthesize beams that are approximately constant in width across three frequency bands covering a 3:1 bandwidth. The array element is a lens-coupled sinuous antenna. The device consists of an array of hemispherical lenses coupled to a lithographed wafer, which integrates TESs, planar sinuous antennas, and microwave circuitry including band-defining filters. The approximately frequency-independent beam widths improve coupling to telescope optics and keep the sensitivity of an experiment close to optimal across a broad frequency range. The design can be straightforwardly modified for use with non-TES lithographed cryogenic detectors such as kinetic inductance detectors. Additionally, we report on the design and measurements of a broadband 180° hybrid that can simplify the design of future multichroic focal planes including but not limited to hierarchical phased arrays.

The effects of five-order nonlinear on the dynamics of dark solitons in optical fiber.

PubMed

He, Feng-Tao; Wang, Xiao-Lin; Duan, Zuo-Liang

2013-01-01

We study the influence of five-order nonlinear on the dynamic of dark soliton. Starting from the cubic-quintic nonlinear Schrodinger equation with the quadratic phase chirp term, by using a similarity transformation technique, we give the exact solution of dark soliton and calculate the precise expressions of dark soliton's width, amplitude, wave central position, and wave velocity which can describe the dynamic behavior of soliton's evolution. From two different kinds of quadratic phase chirps, we mainly analyze the effect on dark soliton's dynamics which different fiver-order nonlinear term generates. The results show the following two points with quintic nonlinearities coefficient increasing: (1) if the coefficients of the quadratic phase chirp term relate to the propagation distance, the solitary wave displays a periodic change and the soliton's width increases, while its amplitude and wave velocity reduce. (2) If the coefficients of the quadratic phase chirp term do not depend on propagation distance, the wave function only emerges in a fixed area. The soliton's width increases, while its amplitude and the wave velocity reduce.

The Effects of Five-Order Nonlinear on the Dynamics of Dark Solitons in Optical Fiber

PubMed Central

Wang, Xiao-Lin; Duan, Zuo-Liang

2013-01-01

We study the influence of five-order nonlinear on the dynamic of dark soliton. Starting from the cubic-quintic nonlinear Schrodinger equation with the quadratic phase chirp term, by using a similarity transformation technique, we give the exact solution of dark soliton and calculate the precise expressions of dark soliton's width, amplitude, wave central position, and wave velocity which can describe the dynamic behavior of soliton's evolution. From two different kinds of quadratic phase chirps, we mainly analyze the effect on dark soliton's dynamics which different fiver-order nonlinear term generates. The results show the following two points with quintic nonlinearities coefficient increasing: (1) if the coefficients of the quadratic phase chirp term relate to the propagation distance, the solitary wave displays a periodic change and the soliton's width increases, while its amplitude and wave velocity reduce. (2) If the coefficients of the quadratic phase chirp term do not depend on propagation distance, the wave function only emerges in a fixed area. The soliton's width increases, while its amplitude and the wave velocity reduce. PMID:23818814

Accretion of Grenvillian terranes to the southwestern border of the Río de la Plata craton, western Argentina

NASA Astrophysics Data System (ADS)

Varela, Ricardo; Basei, Miguel A. S.; González, Pablo D.; Sato, Ana M.; Naipauer, Maximiliano; Campos Neto, Mario; Cingolani, Carlos A.; Meira, Vinicius T.

2011-04-01

A comprehensive review of the geological, geochronological, and isotopic features of the Mesoproterozoic Grenvillian terranes attached to the southwest of the Río de la Plata craton in Early Paleozoic times is presented in this paper. They are grouped into the northern (sierras de Umango, Maz and del Espinal and surroundings), central (Sierra de Pie de Palo, southern Precordillera and Frontal Cordillera), and southern (San Rafael and Las Matras Blocks) segments. The Mesoproterozoic basement consists mainly of arc related, intermediate to acidic and mafic-ultramafic rocks of 1,244-1,027 Ma, with juvenile, Laurentian affinity. Exception to it is the Maz Group, with a protracted history and reworked character. They are affected by 846-570 Ma, extensional magmatism in the northern and central segments, which represents the Neoproterozoic breakup of the Rodinia supercontinent. Successive passive margin sedimentation is registered in Late Neoproterozoic (~640-580 Ma) and Cambro-Ordovician (~550-470 Ma) times. The southern segment is noted for the younger sedimentation alone, and for showing the exclusive primary unconformable relationship between the Mesoproterozoic basement and Early Ordovician cover. The effects of Early Paleozoic Famatinian orogeny, associated with the collisions of Cuyania and Chilenia terranes, are recorded as main phase (480-450 Ma), late phase (440-420 Ma), and Chanic phase (400-360 Ma). Among them, the tectonothermal climax is the Ordovician main phase, to which klippe and nappe structures typical of collisional orogens are related in the northern and central segments. Preliminary data allow us to suggest a set of paired metamorphic belts, with an outboard high-P/T belt, and an inboard Barrowian P/T belt.

UCLA-LANL Reanalysis Project

NASA Astrophysics Data System (ADS)

Shprits, Y.; Chen, Y.; Friedel, R.; Kondrashov, D.; Ni, B.; Subbotin, D.; Reeves, G.; Ghil, M.

2009-04-01

We present first results of the UCLA-LANL Reanalysis Project. Radiation belt relativistic electron Phase Space Density is obtained using the data assimilative VERB code combined with observations from GEO, CRRES, and Akebono data. Reanalysis of data shows the pronounced peaks in the phase space density and pronounced dropouts of fluxes during the main phase of a storm. The results of the reanalysis are discussed and compared to the simulations with the recently developed VERB 3D code.

On the origin of the phase-space diffusion limit in (dis)ordered protein aggregation

NASA Astrophysics Data System (ADS)

Gadomski, A.; Siódmiak, J.; Santamaría-Holek, I.

2013-08-01

Derivation of a phase-space diffusion limit (D-L) allows to obtain a useful formula for a characteristic width of the macroion-channeling filter, controlling model (dis)ordered protein aggregations in a non-ideal aqueous solution. The channel’s width is estimated at the order of an inner half-width of the Stern-type double layer circumventing the growing object and depends in turn on an interplay of the local thermal and electrostatic conditions. The interfacial channeling effect manifests at the edge of biomolecular hydration-duration dependent (non)Markovianity of the system. The interface vs. solution aggregation late-time dynamics are discussed in such local (non)isothermal context with the aim to suggest their experimental assessment.

Analogue modeling of 3-D structural segmentation in fold-and-thrust belts: interactions between frictional and viscous provinces in foreland basins

NASA Astrophysics Data System (ADS)

Borderie, Sandra; Graveleau, Fabien; Witt, César; Vendeville, Bruno C.

2016-04-01

Accretionary wedges are generally segmented both across and along strike because of diverse factors including tectonic and stratigraphic inheritance. In fold-and-thrust belts, along-strike stratigraphic changes in the foreland sequence are classically observed and cause a curvature of the deformation front. Although the parameters controlling this curvature are well documented, the structural interactions and mutual influences between adjacent provinces are much less analyzed. To investigate this question, we deformed analogue models in a compressional box equipped with digital cameras and a topographic measurement apparatus. Models where shortened above a basal frictional detachment (glass microbeads) and segmentation was tested by having a region in which we added an interbedded viscous level (silicone polymer) within the sedimentary cover (dry sand). By changing the number (2 or 3) and the relative width of the purely frictional and viscous provinces, our goal was to characterize geometrically and kinematically the interactions between the viscous and the purely frictional provinces. We used a commercial geomodeller to generate 3-D geometrical models. The results indicate that regardless of the relative width of the purely frictional vs. viscous provinces, the deformation style in the frictional province is not influenced by the presence of the adjacent viscous province. On the contrary, the structural style and the deformation kinematics in the viscous province is significantly impacted by the presence or absence of an adjacent purely frictional province. At first order, the deformation style in the viscous province depends on its width, and three structural styles can be defined along strike. Far from the frictional area, structures are primarily of salt-massif type, and they do not seem to be influenced by the frictional wedge province. Towards the frictional province, deformation changes gradually to a zone of purely forethrusts (foreland verging), and finally to a highly faulted zone with both fore- and backthrusts (hinterland verging). In addition, a kinematic analysis indicates that narrow viscous provinces are strongly influenced by the presence of an adjacent frictional province. Indeed, propagation of shallow thrusts occurs in sequence and the deformation front reaches lately the external décollement pinchout. On the contrary, the deformation front of the wide viscous provinces propagates rapidly to the external décollement pinchout, then younger thrusts form out of sequence. Along-strike segmentation also affects the deep structures (thrusts detaching on the basal frictional décollement). In the viscous province, the presence of an upper viscous décollement opposes the advance of the basal deformation front. There, the rear of the wedge is characterized by imbrications of thrusts sheets (antiformal stacks), and the deep deformation front is convex towards the hinterland. Our experiments allow to better understand the dynamics of salt-controlled fold-and-thrust belts such as in the Huallaga (Peru) and Kuqa (China) basins or the Franklin Mountains (NW Canada).

Evolution of the inner asteroid belt: Paradigms and paradoxes from spectral studies

NASA Technical Reports Server (NTRS)

Gaffey, Michael J.

1987-01-01

Recent years have witnessed a significant increase in the sophistication of asteroidal surface material characterizations derived from spectral data. An extensive data base of moderate to high spectral resolution, visible and near-infrared asteroid spectra is now available. Interpretive methodologies and calibrations were developed to determine phase abundance and composition in olivine-pyroxene assemblages and to estimate NiFe metal abundance from such spectra. A modified version of the asteroid classifications system more closely parallels the mineralogic variations of the major inner belt asteroid types. These improvements permit several general conclusions to be drawn concerning the nature of inner belt objects; their history, and that of the inner solar system; and the relationship between the asteroids and meteorites. Essentially all large belt asteroids have or are fragments of parent bodies which have undergone strong post-accretionary heating, varying degrees of melting and magmatic differentiation, and subsequent collisional disruption. These asteroids show a systematic, but not yet well characterized, mineralogic variation with semi-major axis. This suggests that the S-type asteroid families represent relatively recent collisions onto the cores of previously disrupted parent bodies.

A numerical investigation of the fluid mechanical sewing machine

NASA Astrophysics Data System (ADS)

Brun, P.-T.; Ribe, N. M.; Audoly, B.

2012-04-01

A thin thread of viscous fluid falling onto a moving belt generates a surprising variety of patterns depending on the belt speed, fall height, flow rate, and fluid properties. Here, we simulate this experiment numerically using the discrete viscous threads method that can predict the non-steady dynamics of thin viscous filaments, capturing the combined effects of inertia and of deformation by stretching, bending, and twisting. Our simulations successfully reproduce nine out of ten different patterns previously seen in the laboratory and agree closely with the experimental phase diagram of Morris et al. [Phys. Rev. E 77, 066218 (2008)], 10.1103/PhysRevE.77.066218. We propose a new classification of the patterns based on the Fourier spectra of the longitudinal and transverse motion of the point of contact of the thread with the belt. These frequencies appear to be locked in most cases to simple ratios of the frequency Ωc of steady coiling obtained in the limit of zero belt speed. In particular, the intriguing "alternating loops" pattern is produced by combining the first five multiples of Ωc/3.

Structure, age, and regional significance of syntectonic augen gneisses in the Pan-African Zambezi belt, south-central Zambia

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

Hanson, R.E.; Wilson, T.J.; Wardlaw, M.S.

1985-01-01

The Pan-African Zambezi belt in Zambia contains two major augen gneiss units that are elongated parallel to regional strike. These were previously regarded as slices of sialic basement structurally interleaved with Katangan metasedimentary rocks. New field and geochronologic evidence suggests that the gneisses are syntectonic granites intruded as large concordant sheets during main-phase (D/sub 1/) Pan-African deformation. A pervasive, horizontal or shallowly plunging mineral lineation on S/sub 1/ in the gneisses indicates that the parent granites were injected along major zones of transcurrent shear. The northern gneiss unit shows local discordant contacts against, and contains xenoliths of, adjacent Katangan rocks.more » Large, partly polygonized K-spar augen in the gneiss are wrapped around by S/sub 1/ and offset by microfractures antithetic to S/sub 1/. Finer grained granites intruding the gneiss are penetratively foliated to nondeformed, indicating that they were injected at various times relative to D/sub 1/. In the more intensely deformed southern gneiss unit, local pods of protomylonitic flaser gneiss grade into mylonites containing asymmetric K-spar augen set in a dynamically recrystallized matrix. U-Pb analyses of four fractions plus an air-abraded split of one fraction form a normal linear discordance pattern with an upper intercept of 820 +/- 7 Ma, taken as the age of igneous crystallization. Comparison with other available geochronologic data indicates that this age dates main-phase deformation in the Zambezi belt, and that deformation in the supposedly continuous Damaran belt to the SW was significantly younger.« less

Mesozoic intracontinental underthrust in the SE margin of the North China Block: Insights from the Xu-Huai thrust-and-fold belt

NASA Astrophysics Data System (ADS)

Shu, Liangshu; Yin, Hongwei; Faure, Michel; Chen, Yan

2017-06-01

The Xu-Huai thrust-and-fold belt, located in the southeastern margin of the North China Block, consists mainly of thrust and folded pre-Mesozoic strata. Its geodynamic evolution and tectonic setting are topics of long debate. This paper provides new evidence from geological mapping, structural analysis, and making balance cross-sections, with restoration of cross-sections. Results suggest that this belt was subjected to two-phase deformation, including an early-phase regional-scale NW-ward thrust and fold, and a late-phase extension followed by the emplacement of dioritic, monzodioritic porphyrites dated at 131-135 Ma and locally strike-slip shearing. According to the mapping, field observations and drill-hole data, three structural units were distinguished, namely, (1) the pre-Neoproterozoic crystalline basement in the eastern segment, (2) the nappe unit or the thrust-and-fold zone in the central segment, which is composed of Neoproterozoic to Ordovician carbonate rocks and Carboniferous-Permian coal-bearing rocks, about 2600 m thick, and (3) the western frontal zone. A major decollement fault has also been identified in the base of the nappe unit, on which dozen-meter to km-scale thrust-and-fold bodies were commonly developed. All pre-Mesozoic depositional sequences were involved into a widespread thrust and fold event. Six uncompetent-rock layers with biostratigraphic ages (Nanjing University, 1996) have been recognized, and each uncompetent-rock layer occurred mainly in the top of the footwall, playing an important role in the development of the Xu-Huai thrust-and-fold belt. Geometry of the major decollement fault suggests that the nappe unit of this belt was rooted in its eastern side, near the Tan-Lu Fault Zone. Two geological cross-sections were chosen for structural balancing and restoration. From the balanced cross-sections, ramp-flat and imbricated faults as well as fault-related folds were identified. A shortening of 20.6-29.6 km was obtained from restoration of balanced sections, corresponding to a shortening rate of 43.6-46.4%. This shortening deformation was likely related to the SE-ward intracontinental underthrust of the North China Block beneath the South China Block during the Mesozoic.

VLF Wave Local Acceleration & ULF Wave Radial Diffusion: The Importance of K-Dependent PSD Analysis for Diagnosing the cause of Radiation Belt Acceleration.

NASA Astrophysics Data System (ADS)

Ozeke, L.; Mann, I. R.; Claudepierre, S. G.; Morley, S.; Henderson, M. G.; Baker, D. N.; Kletzing, C.; Spence, H. E.

2017-12-01

We present results showing the temporal evolution of electron Phase Space Density (PSD) in the outer radiation belt during the most intense geomagnetic storm of the last decade which occurred on March 17th 2015. Based on observations of growing local PSD peaks at fixed first and second adiabatic invariants of M=1000 MeV/G and K=0.18 G1/2Re respectively, previous studies argued that the outer radiation belt flux enhancement that occurred during this storm resulted from local acceleration driven by VLF waves. Here we show that the vast majority of the outer radiation belt consisted of electrons with much lower K-values than 0.18 G1/2Re, and that at these lower K-values there is no clear evidence of growing local PSD peaks consistent with that expected from local acceleration. Contrary to prior studies we show that the outer radiation belt flux enhancement is consistent with inward radial diffusion driven by ULF waves and present evidence that the growing local PSD peaks at K=0.18 G1/2Re and M=1000 MeV/G result from pitch-angle scattering of lower-K electrons to K=0.18 G1/2Re. In addition, we also show that the observed outer radiation belt flux enhancement during this geomagnetic storm can be reproduced using a radial diffusion model driven by measured ULF waves without including any local acceleration. These results highlight the importance of careful analysis of the electron PSD profiles as a function of L* over a range of fixed first, M and second K, adiabatic invariants to correctly determine the mechanism responsible for the electron flux enhancements observed in the outer radiation belt.

Effects of chorus, hiss and electromagnetic ion cyclotron waves on radiation belt dynamics (Invited)

NASA Astrophysics Data System (ADS)

Horne, R. B.

2013-12-01

Wave-particle interactions are known to play an important role in the acceleration and loss of radiation belt electrons, and in the heating and loss of ring current ions. The effectiveness of each wave type on radiation belt dynamics depends on the solar wind interaction with the magnetosphere and the properties of the waves which vary considerably with magnetic local time, radial distance and latitude. Furthermore the interaction of the waves with the particles is usually nonlinear. These factors present a major challenge to test and verify the theories. Here we discuss the role of several types of waves, including whistler mode chorus, plasmaspheric hiss, magnetosonic and electromagnetic ion cyclotron waves, in relation to radiation belt and ring current dynamics. We present simulations of the radiation belts using the BAS radiation belt model which includes the effects of chorus, hiss and EMIC waves along with radial diffusion. We show that chorus waves are required to form the peaks in the electron phase space density during storms, and that this occurs inside geostationary orbit. We compare simulations against observations in medium Earth orbit and the new results from Van Allen probes mission that shows conclusive evidence for a local electron acceleration process near L=4.5. We show the relative importance of plasmaspheric hiss and chorus and the location of the plasmapause for radiation belt dynamics near L=4.5 and demonstrate the losses due to EMIC waves that should occur at high energies. Finally we show how improving our basic physical understanding through missions such as Van Allen probes go to improve space weather forecasting in projects such as SPACECAST and have a direct benefit to society.

Effects of pelvic compression belts on the kinematics and kinetics of the lower extremities during sit-to-stand maneuvers

PubMed Central

Kim, Jong Moon; Je, Hyun Dong; Kim, Hyeong-Dong

2017-01-01

[Purpose] To investigate the effects of a pelvic compression belt (PCB) and chair height on the kinematics and kinetics of the lower extremity during sit-to-stand (STS) maneuvers in healthy people. [Subjects and Methods] Twenty-two people participated in this study. They were required to perform STS maneuvers under four conditions. Hip joint moment and angular displacement of the hip, knee, and ankle were measured. A PCB was also applied below the anterior superior iliac spine. [Results] The angular displacement of the ankle joint increased while performing STS maneuvers from a normal chair with a PCB in phase 1, and decreased during phase 2 when performing STS maneuvers from a high chair. The overall angular displacement in phase 3 was decreased while rising from a chair with a PCB and rising from a high chair. When performed STS maneuvers from a high chair, the angular displacement of the hip, knee, and ankle joint decreased considerably in phase 3. This decreased lower extremity motion in phase 3 indicated that participants required less momentum to complete the maneuver. [Conclusion] The results of this study suggest that a PCB might be appropriate for patients with pelvic girdle pain and lower back pain related to pregnancy. PMID:28878454

Effects of pelvic compression belts on the kinematics and kinetics of the lower extremities during sit-to-stand maneuvers.

PubMed

Kim, Jong Moon; Je, Hyun Dong; Kim, Hyeong-Dong

2017-08-01

[Purpose] To investigate the effects of a pelvic compression belt (PCB) and chair height on the kinematics and kinetics of the lower extremity during sit-to-stand (STS) maneuvers in healthy people. [Subjects and Methods] Twenty-two people participated in this study. They were required to perform STS maneuvers under four conditions. Hip joint moment and angular displacement of the hip, knee, and ankle were measured. A PCB was also applied below the anterior superior iliac spine. [Results] The angular displacement of the ankle joint increased while performing STS maneuvers from a normal chair with a PCB in phase 1, and decreased during phase 2 when performing STS maneuvers from a high chair. The overall angular displacement in phase 3 was decreased while rising from a chair with a PCB and rising from a high chair. When performed STS maneuvers from a high chair, the angular displacement of the hip, knee, and ankle joint decreased considerably in phase 3. This decreased lower extremity motion in phase 3 indicated that participants required less momentum to complete the maneuver. [Conclusion] The results of this study suggest that a PCB might be appropriate for patients with pelvic girdle pain and lower back pain related to pregnancy.

X-ray phase scanning setup for non-destructive testing using Talbot-Lau interferometer

NASA Astrophysics Data System (ADS)

Bachche, S.; Nonoguchi, M.; Kato, K.; Kageyama, M.; Koike, T.; Kuribayashi, M.; Momose, A.

2016-09-01

X-ray grating interferometry has a great potential for X-ray phase imaging over conventional X-ray absorption imaging which does not provide significant contrast for weakly absorbing objects and soft biological tissues. X-ray Talbot and Talbot-Lau interferometers which are composed of transmission gratings and measure the differential X-ray phase shifts have gained popularity because they operate with polychromatic beams. In X-ray radiography, especially for nondestructive testing in industrial applications, the feasibility of continuous sample scanning is not yet completely revealed. A scanning setup is frequently advantageous when compared to a direct 2D static image acquisition in terms of field of view, exposure time, illuminating radiation, etc. This paper demonstrates an efficient scanning setup for grating-based Xray phase imaging using laboratory-based X-ray source. An apparatus consisting of an X-ray source that emits X-rays vertically, optical gratings and a photon-counting detector was used with which continuously moving objects across the field of view as that of conveyor belt system can be imaged. The imaging performance of phase scanner was tested by scanning a long continuous moving sample at a speed of 5 mm/s and absorption, differential-phase and visibility images were generated by processing non-uniform moire movie with our specially designed phase measurement algorithm. A brief discussion on the feasibility of phase scanner with scanning setup approach including X-ray phase imaging performance is reported. The successful results suggest a breakthrough for scanning objects those are moving continuously on conveyor belt system non-destructively using the scheme of X-ray phase imaging.

Morphological Adjustment in the Wandering Reach of the Lower Yellow River in Response to the Changes in Water and Sediment Supply over the Recent Decades

NASA Astrophysics Data System (ADS)

Xie, Z.; Huang, H. Q.; Yu, G.

2017-12-01

The flow-sediment regime entering into the LYR has changed significantly since the 1970s due to the increasing intensity of human activities. To understand how the wandering reach of the LYR adjusts its channel morphology in response to the change in the flow-sediment regime, this study extracts a series of channel cross-profiles from remote sensing images taken since 1979. It is shown clearly that at one-year timescale, the main flow has shifted significantly, while the sinuosity of the pathways of main flow increased initially, then decreased significantly from 2006 and experienced little variation since 2010. Meanwhile, the width of the wandering belt has been increasing at a very slow stepwise fashion since 2002, and the area of central bars varied with fluctuations before 2009 and yet took a rapidly increasing trend since then. In contrast, the braiding intensity of the wandering reach has shown little change, while the river channel bed and the width/depth ratio of the main channel have taken significant adjustments, with the channel bed being scoured down to a considerable degree and the width/depth ratio varying in a gradually declining trend. These adjustments in the morphology of the Lower Yellow River implicate that the perched situation of the Lower Yellow River can be reversed.

National Program for Inspection of Non-Federal Dams. Westminster Reservoir Dam (MA 00639) MA 00639, Merrimack River Basin, Westminster, Massachusetts. Phase I Inspection Report.

DTIC Science & Technology

1980-06-01

lot Spooil 2 -.. * -*/ .. . *. . . . . . . , ,_- * j.... . . .\\ %" -* e DEPARTMENT OF THE ARMY 424 TRAPELO ROAD WALTHAM. MASSACHUSETTS 02254 REPLY TO...Feet .El Top .............El. Natural Ground ............. Width Top ........................................ Width of Botton ...nilllwa 4 t mg with M aw =bte wiatg All in good condition.- t -.L E*L. Top EI.Natural Ground Vidth Top________ Width of Borrom Upstream Slope Downstream

Introduction to Phase-Resolving Wave Modeling with FUNWAVE

DTIC Science & Technology

2015-07-01

Boussinesq wave models have become a useful tool for modeling surface wave transformation from deep water to the swash zone, as well as wave-induced...overlapping area of ghost cells, three rows deep , as required by the fourth-order MUSCL-TVD scheme. The MPI with nonblocking communication was used to...implemented ERDC/CHL CHETN-I-87 July 2015 12 SPONGE LAYER SPONGE_ON Sponge_west_width Sponge_east_width Sponge_south_width

Global kinetic simulations of neoclassical toroidal viscosity in low-collisional perturbed tokamak plasmas

NASA Astrophysics Data System (ADS)

Matsuoka, Seikichi; Idomura, Yasuhiro; Satake, Shinsuke

2017-10-01

The neoclassical toroidal viscosity (NTV) caused by a non-axisymmetric magnetic field perturbation is numerically studied using two global kinetic simulations with different numerical approaches. Both simulations reproduce similar collisionality ( νb*) dependencies over wide νb * ranges. It is demonstrated that resonant structures in the velocity space predicted by the conventional superbanana-plateau theory exist in the small banana width limit, while the resonances diminish when the banana width becomes large. It is also found that fine scale structures are generated in the velocity space as νb* decreases in the large banana width simulations, leading to the νb* -dependency of the NTV. From the analyses of the particle orbit, it is found that the finite k∥ mode structure along the bounce motion appears owing to the finite orbit width, and it suffers from bounce phase mixing, suggesting the generation of the fine scale structures by the similar mechanism as the parallel phase mixing of passing particles.

Computational Fluid Dynamics-Population Balance Model Simulation of Effects of Cell Design and Operating Parameters on Gas-Liquid Two-Phase Flows and Bubble Distribution Characteristics in Aluminum Electrolysis Cells

NASA Astrophysics Data System (ADS)

Zhan, Shuiqing; Wang, Junfeng; Wang, Zhentao; Yang, Jianhong

2018-02-01

The effects of different cell design and operating parameters on the gas-liquid two-phase flows and bubble distribution characteristics under the anode bottom regions in aluminum electrolysis cells were analyzed using a three-dimensional computational fluid dynamics-population balance model. These parameters include inter-anode channel width, anode-cathode distance (ACD), anode width and length, current density, and electrolyte depth. The simulations results show that the inter-anode channel width has no significant effect on the gas volume fraction, electrolyte velocity, and bubble size. With increasing ACD, the above values decrease and more uniform bubbles can be obtained. Different effects of the anode width and length can be concluded in different cell regions. With increasing current density, the gas volume fraction and electrolyte velocity increase, but the bubble size keeps nearly the same. Increasing electrolyte depth decreased the gas volume fraction and bubble size in particular areas and the electrolyte velocity increased.

Peaks in Phase Space Density: A Survey of the Van Allen Probes Era

NASA Astrophysics Data System (ADS)

Boyd, A. J.; Turner, D. L.; Reeves, G. D.; Spence, H. E.

2017-12-01

One of the challenges of radiation belt studies is the differentiation between acceleration mechanisms, particularly local acceleration and radial diffusion. This is often done through careful examination of phase space density profiles in terms of adiabatic coordinates. In particular, local acceleration processes produce growing peaks in phase space density. Many previous studies have shown clear observations of these features for individual events. However, it remains unclear how often and where these growing peaks are observed over a long time period. With the availability of several years of high quality observations from multiple spacecraft, we now have an opportunity to quantify phase space density profiles not only for multiple events, but also across a wide range of energies. In this study, we examine phase space density from more than four years of data from the Van Allen Probes and THEMIS to determine the statistical properties of the observed peaks in phase space density. First, we determine how often growing peaks are observed. Second, we examine where the peaks are located in terms of the adiabatic invariants mu, K and L* and how these locations relate to geomagnetic indices, solar wind conditions and the plasmapause location. Third, we explore how these peaks evolve in time. Together, these results will reveal the relative importance of different acceleration processes and how these affect the various electron populations within the radiation belt.

Cenozoic intracontinental deformation of the Kopeh Dagh Belt, Northeastern Iran

NASA Astrophysics Data System (ADS)

Chu, Yang; Wan, Bo; Chen, Ling; Talebian, Morteza

2016-04-01

Compressional intracontinental orogens represent large tectonic zones far from plate boundaries. Since intracontinental mountain belts cannot be framed in the conventional plate tectonics theory, several hypotheses have been proposed to account for the formations of these mountain belts. The far-field effect of collision/subduction at plate margins is now well accepted for the origin and evolution of the intracontinental crust thickening, as exemplified by the Miocene tectonics of central Asia. In northern Iran, the Binalud-Alborz mountain belt witnessed the Triassic tectonothermal events (Cimmerian orogeny), which are interpreted as the result of the Paleotethys Ocean closure between the Eurasia and Central Iran blocks. The Kopeh Dagh Belt, located to the north of the Binalud-Alborz Belt, has experienced two significant tectonic phases: (1) Jurassic to Eocene rifting with more than 7 km of sediments; and (2) Late Eocene-Early Oligocene to Quaternary continuous compression. Due to the high seismicity, deformation associated with earthquakes has received more and more attention; however, the deformation pattern and architecture of this range remain poorly understood. Detailed field observations on the Cenozoic deformation indicate that the Kopeh Dagh Belt can be divided into a western zone and an eastern zone, separated by a series of dextral strike-slip faults, i.e. the Bakharden-Quchan Fault System. The eastern zone characterized by km-scale box-fold structures, associated with southwest-dipping reverse faults and top-to-the NE kinematics. In contrast, the western zone shows top-to-the SW kinematics, and the deformation intensifies from NE to SW. In the northern part of this zone, large-scale asymmetrical anticlines exhibit SW-directed vergence with subordinate thrusts and folds, whereas symmetrical anticlines are observed in the southern part. In regard to its tectonic feature, the Kopeh Dagh Belt is a typical Cenozoic intracontinental belt without ophiolites or arc magmatism. During the Jurassic to Eocene rifting, this belt acted as the southern boundary of the Amu Darya Basin with normal faulting, which is also widespread in the South Caspian Sea and the Black Sea. Moreover, such an extended area became a relatively weak zone within the Eurasian Plate, and could be easily reworked. Because of the collision in the Zagros Belt, the intracontinental compression commenced as early as Late Eocene to Early Oligocene, which is interpreted as tectonic inversion along this weak zone. The western zone of the Kopeh Dagh Belt was also affected by southerly indentation/extrusion of the South Caspian block since middle Miocene, possibly resulting in the different deformation patterns between the western and eastern zones.

Sources and remedies for restraint system discomfort and inconveniences

DOT National Transportation Integrated Search

1974-11-01

This study examines possible causes of failure of autombile occupants to wear restraint systems provided by the manufacturers. Attention is directed primarily to confusion, incovenience and discomfort factors in seat belt usage. Study phases consiste...

Radial transport of radiation belt electrons in kinetic field-line resonances

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

Chaston, Christopher C.; Bonnell, J. W.; Wygant, J. R.

A representative case study from the Van Allen Probes during a geomagnetic storm recovery phase reveals enhanced electron fluxes at intermediate pitch angles over energies from ~100 keV to 5 MeV coincident with broadband low-frequency electromagnetic waves. The statistical properties of these waves are used to build a model for radial diffusion via drift-bounce resonances in kinetic Alfvén eigenmodes/kinetic field-line resonances. Estimated diffusion coefficients indicate timescales for radial transport on the order of hours in storm time events at energies from <100 keV to MeVs over equatorial pitch angles from the edge of the loss cone to nearly perpendicular tomore » the geomagnetic field. In conclusion, the correlation of kinetic resonances with electron depletions and enhancements during storm main phase and recovery, and the rapid diffusion these waves drive, suggests that they may modulate the outer radiation belt.« less

Radial transport of radiation belt electrons in kinetic field-line resonances

DOE PAGES

Chaston, Christopher C.; Bonnell, J. W.; Wygant, J. R.; ...

2017-07-25

A representative case study from the Van Allen Probes during a geomagnetic storm recovery phase reveals enhanced electron fluxes at intermediate pitch angles over energies from ~100 keV to 5 MeV coincident with broadband low-frequency electromagnetic waves. The statistical properties of these waves are used to build a model for radial diffusion via drift-bounce resonances in kinetic Alfvén eigenmodes/kinetic field-line resonances. Estimated diffusion coefficients indicate timescales for radial transport on the order of hours in storm time events at energies from <100 keV to MeVs over equatorial pitch angles from the edge of the loss cone to nearly perpendicular tomore » the geomagnetic field. In conclusion, the correlation of kinetic resonances with electron depletions and enhancements during storm main phase and recovery, and the rapid diffusion these waves drive, suggests that they may modulate the outer radiation belt.« less

Origin and implications of non-radial Imbrium Sculpture on the Moon.

PubMed

Schultz, Peter H; Crawford, David A

2016-07-21

Rimmed grooves, lineations and elongate craters around Mare Imbrium shape much of the nearside Moon. This pattern was coined the Imbrium Sculpture, and it was originally argued that it must have been formed by a giant oblique (~30°) impact, a conclusion echoed by later studies. Some investigators, however, noticed that many elements of the Imbrium Sculpture are not radial to Imbrium, thereby implicating an endogenic or structural origin. Here we use these non-radial trends to conclude that the Imbrium impactor was a proto-planet (half the diameter of Vesta), once part of a population of large proto-planets in the asteroid belt. Such independent constraints on the sizes of the Imbrium and other basin-forming impactors markedly increase estimates for the mass in the asteroid belt before depletion caused by the orbital migration of Jupiter and Saturn. Moreover, laboratory impact experiments, shock physics codes and the groove widths indicate that multiple fragments (up to 2% of the initial diameter) from each oblique basin-forming impactor, such as the one that formed Imbrium, should have survived planetary collisions and contributed to the heavy impact bombardment between 4.3 and 3.8 billion years ago.

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

Schultz, Peter H.; Crawford, David A.

Rimmed grooves, lineations and elongate craters around Mare Imbrium shape much of the nearside Moon. This pattern was coined the Imbrium Sculpture 1, and it was originally argued that it must have been formed by a giant oblique (~30°) impact, a conclusion echoed by later studies 2. Some investigators, however, noticed that many elements of the Imbrium Sculpture are not radial to Imbrium, thereby implicating an endogenic or structural origin 3, 4. Here we use these non-radial trends to conclude that the Imbrium impactor was a proto-planet (half the diameter of Vesta), once part of a population of large proto-planetsmore » in the asteroid belt. Such independent constraints on the sizes of the Imbrium and other basin-forming impactors markedly increase estimates for the mass in the asteroid belt before depletion caused by the orbital migration of Jupiter and Saturn 5. Furthermore, laboratory impact experiments, shock physics codes and the groove widths indicate that multiple fragments (up to 2% of the initial diameter) from each oblique basin-forming impactor, such as the one that formed Imbrium, should have survived planetary collisions and contributed to the heavy impact bombardment between 4.3 and 3.8 billion years ago.« less

Origin and implications of non-radial Imbrium Sculpture on the Moon

NASA Astrophysics Data System (ADS)

Schultz, Peter H.; Crawford, David A.

2016-07-01

Rimmed grooves, lineations and elongate craters around Mare Imbrium shape much of the nearside Moon. This pattern was coined the Imbrium Sculpture, and it was originally argued that it must have been formed by a giant oblique (~30°) impact, a conclusion echoed by later studies. Some investigators, however, noticed that many elements of the Imbrium Sculpture are not radial to Imbrium, thereby implicating an endogenic or structural origin. Here we use these non-radial trends to conclude that the Imbrium impactor was a proto-planet (half the diameter of Vesta), once part of a population of large proto-planets in the asteroid belt. Such independent constraints on the sizes of the Imbrium and other basin-forming impactors markedly increase estimates for the mass in the asteroid belt before depletion caused by the orbital migration of Jupiter and Saturn. Moreover, laboratory impact experiments, shock physics codes and the groove widths indicate that multiple fragments (up to 2% of the initial diameter) from each oblique basin-forming impactor, such as the one that formed Imbrium, should have survived planetary collisions and contributed to the heavy impact bombardment between 4.3 and 3.8 billion years ago.

Statistical properties of the radiation belt seed population

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

Boyd, A. J.; Spence, H. E.; Huang, C. -L.

Here, we present a statistical analysis of phase space density data from the first 26 months of the Van Allen Probes mission. In particular, we investigate the relationship between the tens and hundreds of keV seed electrons and >1 MeV core radiation belt electron population. Using a cross-correlation analysis, we find that the seed and core populations are well correlated with a coefficient of ≈0.73 with a time lag of 10–15 h. We present evidence of a seed population threshold that is necessary for subsequent acceleration. The depth of penetration of the seed population determines the inner boundary of themore » acceleration process. However, we show that an enhanced seed population alone is not enough to produce acceleration in the higher energies, implying that the seed population of hundreds of keV electrons is only one of several conditions required for MeV electron radiation belt acceleration.« less

Observation of Relativistic Electron Microbursts in Conjunction with Intense Radiation Belt Whistler-Mode Waves

NASA Technical Reports Server (NTRS)

Kersten, K.; Cattell, C. A.; Breneman, A.; Goetz, K.; Kellogg, P. J.; Wygant, J. R.; Wilson, L. B., III; Blake, J. B.; Looper, M. D.; Roth, I.

2011-01-01

We present multi-satellite observations of large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron microbursts in near magnetic conjunction with Wind and STEREO. This evidence of microburst precipitation occurring at the same time and at nearly the same magnetic local time and L-shell with a bursty temporal structure similar to that of the observed large amplitude wave packets suggests a causal connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave.particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.

Statistical properties of the radiation belt seed population

DOE PAGES

Boyd, A. J.; Spence, H. E.; Huang, C. -L.; ...

2016-07-25

Here, we present a statistical analysis of phase space density data from the first 26 months of the Van Allen Probes mission. In particular, we investigate the relationship between the tens and hundreds of keV seed electrons and >1 MeV core radiation belt electron population. Using a cross-correlation analysis, we find that the seed and core populations are well correlated with a coefficient of ≈0.73 with a time lag of 10–15 h. We present evidence of a seed population threshold that is necessary for subsequent acceleration. The depth of penetration of the seed population determines the inner boundary of themore » acceleration process. However, we show that an enhanced seed population alone is not enough to produce acceleration in the higher energies, implying that the seed population of hundreds of keV electrons is only one of several conditions required for MeV electron radiation belt acceleration.« less

Quantifying Energetic Electron Precipitation And Its Effect on Atmospheric Chemistry

NASA Astrophysics Data System (ADS)

Huang, C. L.; Spence, H. E.; Smith, S. S.; Duderstadt, K. A.; Boyd, A. J.; Geoffrey, R.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Turner, D. L.; Crew, A. B.; Klumpar, D. M.; Shumko, M.; Johnson, A.; Sample, J. G.

2017-12-01

In this study we quantify the total radiation belt electron loss through precipitation into the atmosphere, and simulate the electrons' contribution to changing the atmospheric composition. We use total radiation belt electron content (TRBEC) calculated from Van Allen Probes ECT/MagEIS data to estimate the precipitation during electron loss events. The new TRBEC index is a high-level quantity for monitoring the entire radiation belt and has the benefit of removing both internal transport and the adiabatic effect. To assess the electron precipitation rate, we select TRBEC loss events that show no outward transport in the phase space density data in order to exclude drift magnetopause loss. Then we use FIREBIRD data to estimate and constrain the precipitation loss when it samples near the loss cone. Finally, we estimate the impact of electron precipitation on the composition of the upper and middle atmosphere using global climate simulations.

Explaining the Diverse Response of the Ultra-relativistic Van Allen Radiation Belt to Solar Wind Forcing

NASA Astrophysics Data System (ADS)

Mann, I. R.; Ozeke, L.; Murphy, K. R.; Claudepierre, S. G.; Rae, J.; Milling, D. K.; Kale, A.; Baker, D. N.

2017-12-01

The NASA Van Allen Probes have opened a new window on the dynamics of ultra-relativistic electrons in the Van Allen radiation belts. Under different solar wind forcing the outer belt is seen to respond in a variety of apparently diverse and sometimes remarkable ways. For example, sometimes a third radiation belt is carved out (e.g., September 2012), or the belts can remain depleted for 10 days or more (September 2014). More usually there is a sequential response of a strong and sometimes rapid depletion followed by a re-energization, the latter increasing outer belt electron flux by orders of magnitude on hour timescales during some of the strongest storms of this solar cycle (e.g., March 2013, March 2015). Such dynamics also appear to be often bounded at low-L by an apparently impenetrable barrier at L 2.8 through which ultra-relativistic electrons do not penetrate. Many studies in the Van Allen Probes era have sought explanations for these apparently diverse features, often incorporating the effects from multiple plasma waves. In contrast, we show how this apparently diverse behaviour can instead be explained by one dominant process: ULF wave radial transport. Once ULF wave transport rates are accurately specified by observations, and coupled to the dynamical variation of the outer boundary condition at the edge of the outer belt, the observed diverse responses can all be explained. However, in order to get good agreement with observations, the modeling reveals the importance of still currently unexplained very fast loss in the main phase which results in an almost total extinction of the belts and decouples pre- and post-storm ultra-relativistic electron flux on hour timescales. Similarly, varying plasmasheet source populations are seen to be of critical importance such that near-tail dynamics play a crucial role in Van Allen belt dynamics. Nonetheless, simple models incorporating accurate transport rates derived directly from ULF wave measurements are shown to provide a single natural, compelling, and at times elegant explanation for such previously unexplained and apparently diverse responses to solar wind forcing.

Kuiper belt structure around nearby super-Earth host stars

NASA Astrophysics Data System (ADS)

Kennedy, Grant M.; Matrà, Luca; Marmier, Maxime; Greaves, Jane S.; Wyatt, Mark C.; Bryden, Geoffrey; Holland, Wayne; Lovis, Christophe; Matthews, Brenda C.; Pepe, Francesco; Sibthorpe, Bruce; Udry, Stéphane

2015-05-01

We present new observations of the Kuiper belt analogues around HD 38858 and HD 20794, hosts of super-Earth mass planets within 1 au. As two of the four nearby G-type stars (with HD 69830 and 61 Vir) that form the basis of a possible correlation between low-mass planets and debris disc brightness, these systems are of particular interest. The disc around HD 38858 is well resolved with Herschel and we constrain the disc geometry and radial structure. We also present a probable James Clerk Maxwell Telescope sub-mm continuum detection of the disc and a CO J = 2-1 upper limit. The disc around HD 20794 is much fainter and appears marginally resolved with Herschel, and is constrained to be less extended than the discs around 61 Vir and HD 38858. We also set limits on the radial location of hot dust recently detected around HD 20794 with near-IR interferometry. We present High Accuracy Radial velocity Planet Searcher upper limits on unseen planets in these four systems, ruling out additional super-Earths within a few au, and Saturn-mass planets within 10 au. We consider the disc structure in the three systems with Kuiper belt analogues (HD 69830 has only a warm dust detection), concluding that 61 Vir and HD 38858 have greater radial disc extent than HD 20794. We speculate that the greater width is related to the greater minimum planet masses (10-20 M⊕ versus 3-5 M⊕), arising from an eccentric planetesimal population analogous to the Solar system's scattered disc. We discuss alternative scenarios and possible means to distinguish among them.

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

Steele, Amy; Hughes, A. Meredith; Carpenter, John

The presence of debris disks around young main-sequence stars hints at the existence and structure of planetary systems. Millimeter-wavelength observations probe large grains that trace the location of planetesimal belts. The Formation and Evolution of Planetary Systems Spitzer Legacy survey of nearby young solar analogues yielded a sample of five debris disk-hosting stars with millimeter flux suitable for interferometric follow-up. We present observations with the Submillimeter Array (SMA) and the Combined Array for Research in Millimeter-wave Astronomy at ∼2″ resolution that spatially resolve the debris disks around these nearby (d ∼ 50 pc) stars. Two of the five disks (HDmore » 377, HD 8907) are spatially resolved for the first time and one (HD 104860) is resolved at millimeter wavelengths for the first time. We combine our new observations with archival SMA and Atacama Large Millimeter/Submillimeter Array data to enable a uniform analysis of the full five-object sample. We simultaneously model the broadband photometric data and resolved millimeter visibilities to constrain the dust temperatures and disk morphologies, and perform a Markov Chain Monte Carlo analysis to fit for basic structural parameters. We find that the radii and widths of the cold outer belts exhibit properties consistent with scaled-up versions of the Solar System's Kuiper Belt. All the disks exhibit characteristic grain sizes comparable to the blowout size, and all the resolved observations of emission from large dust grains are consistent with an axisymmetric dust distribution to within the uncertainties. These results are consistent with comparable studies carried out at infrared wavelengths.« less

The Dynamics of Hadley Circulation Variability and Change

NASA Astrophysics Data System (ADS)

Davis, Nicholas Alexander

The Hadley circulation exerts a dominant control on the surface climate of earth's tropical belt. Its converging surface winds fuel the tropical rains, while subsidence in the subtropics dries and stabilizes the atmosphere, creating deserts on land and stratocumulus decks over the oceans. Because of the strong meridional gradients in temperature and precipitation in the subtropics, any shift in the Hadley circulation edge could project as major changes in surface climate. While climate model simulations predict an expansion of the Hadley cells in response to greenhouse gas forcings, the mechanisms remain elusive. An analysis of the climatology, variability, and response of the Hadley circulation to radiative forcings in climate models and reanalyses illuminates the broader landscape in which Hadley cell expansion is realized. The expansion is a fundamental response of the atmosphere to increasing greenhouse gas concentrations as it scales with other key climate system changes, including polar amplification, increasing static stability, stratospheric cooling, and increasing global-mean surface temperatures. Multiple measures of the Hadley circulation edge latitudes co-vary with the latitudes of the eddy-driven jets on all timescales, and both exhibit a robust poleward shift in response to forcings. Further, across models there is a robust coupling between the eddy-driving on the Hadley cells and their width. On the other hand, the subtropical jet and tropopause break latitudes, two common observational proxies for the tropical belt edges, lack a strong statistical relationship with the Hadley cell edges and have no coherent response to forcings. This undermines theories for the Hadley cell width predicated on angular momentum conservation and calls for a new framework for understanding Hadley cell expansion. A numerical framework is developed within an idealized general circulation model to isolate the mean flow and eddy responses of the global atmosphere to radiative forcings. It is found that it is primarily the eddy response to greenhouse-gas-like forcings that causes Hadley cell expansion. However, the mean flow changes in the Hadley circulation itself crucially mediate this eddy response such that the full response comes about due to eddy-mean flow interactions. A theoretical scaling for the Hadley cell width based on moist static energy is developed to provide an improved framework to understand climate change responses of the general circulation. The scaling predicts that expansion is driven by increases in the surface latent heat flux and the width of the rising branch of the circulation and opposed by increases in tropospheric radiative cooling. A reduction in subtropical moist static energy flux divergence by the eddies is key, as it tilts the energetic balance in favor of expansion.

Preliminary investigation of gold mineralization in the Pedro Dome-Cleary Summit area, Fairbanks district, Alaska

USGS Publications Warehouse

Pilkington, H.D.; Forbes, R.B.; Hawkins, D.B.; Chapman, R.M.; Swainbank, R.C.

1969-01-01

Anomalous gold values in mineralized veins and hydrothermally altered quartz-mica schist in the Pedro Dome-Cleary Summit area of the Fairbanks district suggest the presence of numerous small low- to high-grade lodes. Anomalous concentrations of gold were found to exist in the wall rocks adjacent to mineralized veins. In general, the gold concentration gradients in these wall rocks are much too steep to increase appreciably the mineable width of the veins. Anomalous gold values were also detected in bedrock samples taken by means of a power auger on the Murphy Dome Road along the southwest extension of the Pedro Dome-Cleary Summit mineralized belt.

Simulating the Heterogeneity in Braided Channel Belt Deposits: 2. Examples of Results and Comparison to Natural Deposits

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

Guin, Arijit; Ramanathan, Ramya; Ritzi, Robert W.

In Part 1 of this series we presented a methodology and a code for modeling the hierarchical sedimentary architecture in braided channel belt deposits. Here, in Part 2, the code was used to create a digital model of this architecture, and the corresponding spatial distribution of permeability. The simulated architecture was compared to the real stratal architecture observed in an abandoned channel belt of the Sagavanirktok River, Alaska by Lunt et al. (2004). The comparisons included assessments of similarity which were both qualitative and quantitative. From the qualitative comparisons we conclude that a synthetic deposit created by the code hasmore » unit types, at each level, with a geometry which is generally consistent with the geometry of unit types observed in the field. The digital unit types would generally be recognized as representing their counterparts in nature, including cross stratasets, lobate and scroll bar deposits, channel fills, etc. Furthermore, the synthetic deposit has a hierarchical spatial relationship among these units which represents how the unit types are observed in field exposures and in geophysical images. In quantitative comparisons the proportions and the length, width, and height of unit types at different scales, across all levels of the stratal hierarchy compare well between the digital and the natural deposits. A number of important attributes of the channel belt model were shown to be influenced by more than one level within the hierarchy of stratal architecture. First, the high-permeability open-framework gravels percolated at all levels and thus formed preferential flow pathways. Open framework gravels are indeed known to form preferential flow pathways in natural channel belt deposits. The nature of a percolating cluster changed across different levels of the hierarchy of stratal architecture. As a result of this geologic structure, the percolation occurs at proportions of open-framework gravels below the theoretical percolation threshold for random infinite media. Second, when the channel belt model was populated with permeability distributions by lowest-level unit type, the composite permeability semivariogram contained structures that were identifiable at more than one scale, and each of these structures could be directly linked to unit types of different scales existing at different levels within the hierarchy of strata. These collective results are encouraging with respect to our goal that this model be relevant as a base case in future studies for testing ideas in research addressing the upscaling problem in aquifers and reservoirs with multi-scale heterogeneity.« less

Design of multiplier-less sharp transition width non-uniform filter banks using gravitational search algorithm

NASA Astrophysics Data System (ADS)

Bindiya T., S.; Elias, Elizabeth

2015-01-01

In this paper, multiplier-less near-perfect reconstruction tree-structured filter banks are proposed. Filters with sharp transition width are preferred in filter banks in order to reduce the aliasing between adjacent channels. When sharp transition width filters are designed as conventional finite impulse response filters, the order of the filters will become very high leading to increased complexity. The frequency response masking (FRM) method is known to result in linear-phase sharp transition width filters with low complexity. It is found that the proposed design method, which is based on FRM, gives better results compared to the earlier reported results, in terms of the number of multipliers when sharp transition width filter banks are needed. To further reduce the complexity and power consumption, the tree-structured filter bank is made totally multiplier-less by converting the continuous filter bank coefficients to finite precision coefficients in the signed power of two space. This may lead to performance degradation and calls for the use of a suitable optimisation technique. In this paper, gravitational search algorithm is proposed to be used in the design of the multiplier-less tree-structured uniform as well as non-uniform filter banks. This design method results in uniform and non-uniform filter banks which are simple, alias-free, linear phase and multiplier-less and have sharp transition width.

Geological, petrogical and geochemical characteristics of granitoid rocks in Burma: with special reference to the associated WSn mineralization and their tectonic setting

NASA Astrophysics Data System (ADS)

Zaw, Khin

The granitoid rocks in Burma extend over a distance of 1450 km from Putao, Kachin State in the north, through Mogok, Kyaukse, Yamethin and Pyinmana in the Mandalay Division, to Tavoy and Mergui areas, Tenasserim Division, in the south. The Burmese granitoids can be subdivided into three N-S trending, major belts viz. western granitoid belt, central graniotoid belt and eastern granitoid belt. The Upper Cretaceous-Lower Eocene western belt granitoids are characterized by high-level intrusions associated with porphyry Cu(Au) related, younger volcanics; these plutonic and volcanic rocks are thought to have been emplaced as a magmatic-volcanic arc (inner magmatic-volcanic arc) above an east-dipping, but westwardly migrating, subduction zone related to the prolonged plate convergence which occurred during Upper Mesozoic and Cenozoic. The central granitoid belt is characterized by mesozonal, Mostly Upper Cretaceous to Lower Eocene plutons associated with abundant pegmalites and aplites, numerous vein-type W-Sn deposits and rare co-magmatic volcanics. The country rocks are structurally deformed, metamorphic rocks of greenschist to upper amphibolite facies ranging in age as early as Upper Precambrian to Upper Paleozoic and locally of fossiliferous, metaclastic rocks (Mid Jurassic to Lower Cretaceous). Available K/Ar radiometric data indicate significant and possibly widespread thermal disturbances in the central granitoid belt during the Tertiary (mostly Miocence). In this study, the distribution, lithological, textural and structural characteristics of the central belt granitoids are reviewed, and their mineralogical, petrological, and geochemical features are presented. A brief description of W-Sn ore veins associated with these granitoid plutons is also reported. Present geological, petrological and geochemical evidences demonstrate that the W-Sn related, central belt granitoids are mostly granodiorite and granite which are commonly transformed into granitoid gneisses. These central belt granitoids were formed from a calc-alkaline magma derived from a source of continental, sialic materials. Highly potassiccharacters and high initial Sr 87/Sr 86 ratios (0.717±0.002) and Rb/Sr ratios (0.40-33.10) with an average value of 6.70, further corroborate their derivation from a well established continental, sialic basement. Although future chemical and isotopic investigations would be desirable, none of the present evidence argues the interpretation that the granitoid magma was generated by the re-melting of the regionally metamorphosed country rocks. The close association of W-Sn bearing quartz veins and the granitoid rocks also suggests that the metals were derived from the same crustal sources as their host granitoids. The central belt granitoids are considered to have been emplaced during the continent-arc collision of inferred Upper Triassic-Jurassic magmatic-volcanic arc with the continental foreland to the east at the early stage of westward migration of the east-dipping subduction zone to the west. The W-Sn related, central belt granitoids of Upper Mesozoic-Lower Eocene are notably different from those of mainly Triassic granitoids from northern Thailand and Permo-Triassic granites of the Malay Peninsula, and thus the central belt granitoids were emplaced in a uniquely distinct geologic and tetonic setting in the SE Asian region. Major element data for the central belt granitoids, which are associated with W-Sn mineralization lie within the field of Sn-mineralizing granites from New England in Na-K-Ca plot (Juniper and Kleeman, J. Geochem. Explor.11, 321-333, 1979), but largely outside the field on SiO 2CaO +_MgO + FeONa 2O + K 2O + Al 2O 3 plot. Trace element abundances of the central belt granitoid rocks suggest that the Sn content of the granitoids alone should be used with great caution to discriminate the W-Sn bearing (mineralized) granitoid plutons from the W-Sn poor (barren) plutons in search for the W-Sn deposits in Burma, but trace element data show the tendency for granitoid plutons which bear W-Sn mineralization to be comparatively more enriched in Be, Bi, Cu, Mo, Pb, Sn, Y, and Zn, but less depleted in Ba and Zr than those plutons in which no W-Sn occurrences are recorded. The eastern belt granitoids are still largely unknown but characterized by medium to coarsely porphyritic textures and country rocks of regionally metamorphosed, turbiditic sediments of Chaung Magyi Group (Upper Precambrian). This eastern granitoid belt lies immediately to the north of mostly Triassic granitoids in northern Thailand, and the Sn-W bearing, mesozonal, Permo-Triassic, Main Range granitoids in the western part of the Malay Peninsula. The latter granitoid swere considered to have been emplaced during continental collision, but geologic and tectonic information for the eastern belt grantoids in Burma are still incomplete to confirm this contention. Alternatively, present available geologic evidences cannot rule out the possibility that the eastern belt granitoids were emplaced in a continental margin above an eastward subducting ocean floor during the Lower Paleozoic. According to the criteria given by Chappell and White ( Pacific Geol.8, 173-174, 1974), the porphyry Cu(Au)-related, western granitoid belt plutons have I-type characteristics, whereas the W-Sn related, central granitoid belt contains both the hornblende-bearing I-type granitoids as older intrusive phases and the W-Sn bearing, S-type granitoids as younger plutonic phases. The eastern belt granitoids cannot be classified as being of either I- or S-type, as petrochemical data are still lacking.

A novel single-phase flux-switching permanent magnet linear generator used for free-piston Stirling engine

NASA Astrophysics Data System (ADS)

Zheng, Ping; Sui, Yi; Tong, Chengde; Bai, Jingang; Yu, Bin; Lin, Fei

2014-05-01

This paper investigates a novel single-phase flux-switching permanent-magnet (PM) linear machine used for free-piston Stirling engines. The machine topology and operating principle are studied. A flux-switching PM linear machine is designed based on the quasi-sinusoidal speed characteristic of the resonant piston. Considering the performance of back electromotive force and thrust capability, some leading structural parameters, including the air gap length, the PM thickness, the ratio of the outer radius of mover to that of stator, the mover tooth width, the stator tooth width, etc., are optimized by finite element analysis. Compared with conventional three-phase moving-magnet linear machine, the proposed single-phase flux-switching topology shows advantages in less PM use, lighter mover, and higher volume power density.

THE EVOLUTION OF ASTEROIDS IN THE JUMPING-JUPITER MIGRATION MODEL

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

Roig, Fernando; Nesvorný, David, E-mail: froig@on.br, E-mail: davidn@boulder.swri.edu

In this work, we investigate the evolution of a primordial belt of asteroids, represented by a large number of massless test particles, under the gravitational effect of migrating Jovian planets in the framework of the jumping-Jupiter model. We perform several simulations considering test particles distributed in the Main Belt, as well as in the Hilda and Trojan groups. The simulations start with Jupiter and Saturn locked in the mutual 3:2 mean motion resonance plus three Neptune-mass planets in a compact orbital configuration. Mutual planetary interactions during migration led one of the Neptunes to be ejected in less than 10 Myrmore » of evolution, causing Jupiter to jump by about 0.3 AU in semimajor axis. This introduces a large-scale instability in the studied populations of small bodies. After the migration phase, the simulations are extended over 4 Gyr, and we compare the final orbital structure of the simulated test particles to the current Main Belt of asteroids with absolute magnitude H < 9.7. The results indicate that, in order to reproduce the present Main Belt, the primordial belt should have had a distribution peaked at ∼10° in inclination and at ∼0.1 in eccentricity. We discuss the implications of this for the Grand Tack model. The results also indicate that neither primordial Hildas, nor Trojans, survive the instability, confirming the idea that such populations must have been implanted from other sources. In particular, we address the possibility of implantation of Hildas and Trojans from the Main Belt population, but find that this contribution should be minor.« less

Homogeneous and inhomogeneous broadenings and the Voigt line shapes in the phase-resolved and intensity sum-frequency generation vibrational spectroscopy

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

Chen, Shunli; Fu, Li; Gan, Wei

2016-01-21

In this report we show that the ability to measure the sub-1 cm -1 resolution phase-resolved and intensity high-resolution broadband sum frequency generation vibrational spectra (HR-BB-SFG-VS) of the –CN stretch vibration of the Langmuir-Blodgett (LB) monolayer of the 4-n-octyl-4’-cyanobiphenyl (8CB) on the z-cut α-quartz surface allows for the first time the direct comparison and understanding of the homogeneous and inhomogeneous broadenings in the imaginary and intensity SFG vibrational spectral lineshapes in detail. The difference of the full width at half maxima (FWHM) of the imaginary and intensity SFG-VS spectra of the same vibrational mode is the signature of the Voigtmore » lineshape and it measures the relative contribution to the overall lineshape from the homogeneous and inhomogeneous broadenings in SFG vibrational spectra. From the phase-resolved and intensity spectra, we found that the FWHM of the 2238.00 ±0.02 cm -1 peak in the phase-resolved imaginary and intensity spectra is 19.2 ± 0.2 cm -1 and 21.6 ± 0.4 cm -1, respectively, for the –CN group of the 8CB LB monolayer on the z-cut α-quartz crystal surface. The FWHM width difference of 2.4 cm -1 agrees quantitatively with a Voigt lineshape with a homogeneous broadening half width of Γ = 5.29 ± 0.08 cm -1 and a inhomogeneous standard derivation width Δω = 5.42 ± 0.07 cm -1. These results shed new lights on the understanding and interpretation of the lineshapes of both the phase-resolved and the intensity SFG vibrational spectra, as well as other incoherent and coherent spectroscopic techniques in general.« less

Homogeneous and inhomogeneous broadenings and the Voigt line shapes in the phase-resolved and intensity sum-frequency generation vibrational spectroscopy.

PubMed

Chen, Shun-Li; Fu, Li; Gan, Wei; Wang, Hong-Fei

2016-01-21

In this report, we show that the ability to measure the sub-1 cm(-1) resolution phase-resolved and intensity high-resolution broadband sum frequency generation vibrational spectra of the -CN stretch vibration of the Langmuir-Blodgett (LB) monolayer of the 4-n-octyl-4'-cyanobiphenyl (8CB) on the z-cut α-quartz surface allows the direct comparison and understanding of the homogeneous and inhomogeneous broadenings in the imaginary and intensity SFG vibrational spectral line shapes in detail. The difference of the full width at half maximum (FWHM) of the imaginary and intensity sum-frequency generation vibrational spectroscopy spectra of the same vibrational mode is the signature of the Voigt line shape and it measures the relative contribution to the overall line shape from the homogeneous and inhomogeneous broadenings in SFG vibrational spectra. From the phase-resolved and intensity spectra, we found that the FWHM of the 2238.00 ± 0.02 cm(-1) peak in the phase-resolved imaginary and intensity spectra is 19.2 ± 0.2 cm(-1) and 21.6 ± 0.4 cm(-1), respectively, for the -CN group of the 8CB LB monolayer on the z-cut α-quartz crystal surface. The FWHM width difference of 2.4 cm(-1) agrees quantitatively with a Voigt line shape with a homogeneous broadening half width of Γ = 5.29 ± 0.08 cm(-1) and an inhomogeneous standard derivation width Δω = 5.42 ± 0.07 cm(-1). These results shed new lights on the understanding and interpretation of the line shapes of both the phase-resolved and the intensity SFG vibrational spectra, as well as other incoherent and coherent spectroscopic techniques in general.

Electrical system for pulse-width modulated control of a power inverter using phase-shifted carrier signals and related operating methods

DOEpatents

Welchko, Brian A [Torrance, CA

2012-02-14

Systems and methods are provided for pulse-width modulated control of power inverter using phase-shifted carrier signals. An electrical system comprises an energy source and a motor. The motor has a first set of windings and a second set of windings, which are electrically isolated from each other. An inverter module is coupled between the energy source and the motor and comprises a first set of phase legs coupled to the first set of windings and a second set of phase legs coupled to the second set of windings. A controller is coupled to the inverter module and is configured to achieve a desired power flow between the energy source and the motor by modulating the first set of phase legs using a first carrier signal and modulating the second set of phase legs using a second carrier signal. The second carrier signal is phase-shifted relative to the first carrier signal.

Pulse width modulation inverter with battery charger

DOEpatents

Slicker, James M.

1985-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Pulse width modulation inverter with battery charger

NASA Technical Reports Server (NTRS)

Slicker, James M. (Inventor)

1985-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

Properties of interfaces and transport across them.

PubMed

Cabezas, H

2000-01-01

Much of the biological activity in cell cytoplasm occurs in compartments some of which may be formed, as suggested in this book, by phase separation, and many of the functions of such compartments depend on the transport or exchange of molecules across interfaces. Thus a fundamentally based discussion of the properties of phases, interfaces, and diffusive transport across interfaces has been given to further elucidate these phenomena. An operational criterion for the width of interfaces is given in terms of molecular and physical arguments, and the properties of molecules inside phases and interfaces are discussed in terms of molecular arguments. In general, the properties of the interface become important when the molecules diffusing across are smaller than the width of the interface. Equilibrium partitioning, Donnan phenomena, and electrochemical potentials at interfaces are also discussed in detail. The mathematical expressions for modeling transport across interfaces are discussed in detail. These describe a practical and detailed model for transport across interfaces. For molecules smaller than the width of the interface, this includes a detailed model for diffusion inside the interface. Last, the question of the time scale for phase formation and equilibration in biological systems is discussed.

2004 EW95: A Phyllosilicate-bearing Carbonaceous Asteroid in the Kuiper Belt

NASA Astrophysics Data System (ADS)

Seccull, Tom; Fraser, Wesley C.; Puzia, Thomas H.; Brown, Michael E.; Schönebeck, Frederik

2018-03-01

Models of the Solar System’s dynamical evolution predict the dispersal of primitive planetesimals from their formative regions among the gas-giant planets due to the early phases of planetary migration. Consequently, carbonaceous objects were scattered both into the outer asteroid belt and out to the Kuiper Belt. These models predict that the Kuiper Belt should contain a small fraction of objects with carbonaceous surfaces, though to date, all reported visible reflectance spectra of small Kuiper Belt Objects (KBOs) are linear and featureless. We report the unusual reflectance spectrum of a small KBO, (120216) 2004 EW95, exhibiting a large drop in its near-UV reflectance and a broad shallow optical absorption feature centered at ∼700 nm, which is detected at greater than 4σ significance. These features, confirmed through multiple epochs of spectral photometry and spectroscopy, have respectively been associated with ferric oxides and phyllosilicates. The spectrum bears striking resemblance to those of some C-type asteroids, suggesting that 2004 EW95 may share a common origin with those objects. 2004 EW95 orbits the Sun in a stable mean motion resonance with Neptune, at relatively high eccentricity and inclination, suggesting it may have been emplaced there by some past dynamical instability. These results appear consistent with the aforementioned model predictions and are the first to show a reliably confirmed detection of silicate material on a small KBO.

THE CANADA-FRANCE ECLIPTIC PLANE SURVEY-FULL DATA RELEASE: THE ORBITAL STRUCTURE OF THE KUIPER BELT

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

Petit, J.-M.; Rousselot, P.; Mousis, O.

2011-10-15

We report the orbital distribution of the trans-Neptunian objects (TNOs) discovered during the Canada-France Ecliptic Plane Survey (CFEPS), whose discovery phase ran from early 2003 until early 2007. The follow-up observations started just after the first discoveries and extended until late 2009. We obtained characterized observations of 321 deg{sup 2} of sky to depths in the range g {approx} 23.5-24.4 AB mag. We provide a database of 169 TNOs with high-precision dynamical classification and known discovery efficiency. Using this database, we find that the classical belt is a complex region with sub-structures that go beyond the usual splitting of innermore » (interior to 3:2 mean-motion resonance [MMR]), main (between 3:2 and 2:1 MMR), and outer (exterior to 2:1 MMR). The main classical belt (a = 40-47 AU) needs to be modeled with at least three components: the 'hot' component with a wide inclination distribution and two 'cold' components (stirred and kernel) with much narrower inclination distributions. The hot component must have a significantly shallower absolute magnitude (H{sub g} ) distribution than the other two components. With 95% confidence, there are 8000{sup +1800}{sub -1600} objects in the main belt with H{sub g} {<=} 8.0, of which 50% are from the hot component, 40% from the stirred component, and 10% from the kernel; the hot component's fraction drops rapidly with increasing H{sub g} . Because of this, the apparent population fractions depend on the depth and ecliptic latitude of a trans-Neptunian survey. The stirred and kernel components are limited to only a portion of the main belt, while we find that the hot component is consistent with a smooth extension throughout the inner, main, and outer regions of the classical belt; in fact, the inner and outer belts are consistent with containing only hot-component objects. The H{sub g} {<=} 8.0 TNO population estimates are 400 for the inner belt and 10,000 for the outer belt to within a factor of two (95% confidence). We show how the CFEPS Survey Simulator can be used to compare a cosmogonic model for the orbital element distribution to the real Kuiper Belt.« less

Effect of particle size distribution on the separation efficiency in liquid chromatography.

PubMed

Horváth, Krisztián; Lukács, Diána; Sepsey, Annamária; Felinger, Attila

2014-09-26

In this work, the influence of the width of particle size distribution (PSD) on chromatographic efficiency is studied. The PSD is described by lognormal distribution. A theoretical framework is developed in order to calculate heights equivalent to a theoretical plate in case of different PSDs. Our calculations demonstrate and verify that wide particle size distributions have significant effect on the separation efficiency of molecules. The differences of fully porous and core-shell phases regarding the influence of width of PSD are presented and discussed. The efficiencies of bimodal phases were also calculated. The results showed that these packings do not have any advantage over unimodal phases. Copyright © 2014 Elsevier B.V. All rights reserved.

Bunch shape monitor development in J-PARC linac

NASA Astrophysics Data System (ADS)

Miura, A.; Tamura, J.; Liu, Y.; Miyao, T.

2017-07-01

In the linac at the Japan accelerator research complex (J-PARC), we decided to use bunch shape monitors (BSMs) as phase-width monitors. Both centroid-phase set point at the frequency jump from SDTL (324 MHz) to ACS (972 MHz) and phase-width control are key issues for suppressing excess beam loss. BSM was designed and developed at the Institute for Nuclear Research, Russia. Because the BSM was first used between acceleration cavities, we need to improve it to protect it from the leakage-magnetic field of the quadrupole magnets and from outgassing impacts on the cavities. In this paper, we introduce these improvements to the BSM for the adoption of the location nearby the acceleration cavities.

Electric Field Tunable Microwave and MM-wave Ferrite Devices

DTIC Science & Technology

2010-04-30

xm thick YIG film grown by liquid-phase epitaxy on a (111) gadolinium gallium garnet was used. A PZT plate with the dimensions 4x1x0.5 mm3 was...of width ~ 150 micron and length 20 mm. An YIG film , 6 u.m thick, 0.5 mm in width and 2.5 mm long, grown on a 0.5 mm thick gadolinium gallium garnet ...yttrium iron garnet film and a ceramic barium strontium titanate slab. The electrical tunability of the differential phase shift Acp is achieved through

Increased water retention in polymer electrolyte membranes at elevated temperatures assisted by capillary condensation.

PubMed

Park, Moon Jeong; Downing, Kenneth H; Jackson, Andrew; Gomez, Enrique D; Minor, Andrew M; Cookson, David; Weber, Adam Z; Balsara, Nitash P

2007-11-01

We establish a new systematic methodology for controlling the water retention of polymer electrolyte membranes. Block copolymer membranes comprising hydrophilic phases with widths ranging from 2 to 5 nm become wetter as the temperature of the surrounding air is increased at constant relative humidity. The widths of the moist hydrophilic phases were measured by cryogenic electron microscopy experiments performed on humid membranes. Simple calculations suggest that capillary condensation is important at these length scales. The correlation between moisture content and proton conductivity of the membranes is demonstrated.

Interface motion in a two-dimensional Ising model with a field

NASA Astrophysics Data System (ADS)

Devillard, Pierre

1991-01-01

We determine by Monte Carlo simulations the width of an interface between the stable phase and the metastable phase in a two-dimensional Ising model with a magnetic field, in the case of nonconversed order parameter (Glauber dynamics). At zero temperature, the width increases as t β with β-1/3, as predicted by earlier theories. As temperature increases, the value of the effective exponent β that we measure decreases toward the value 1/4, which is the value in the absence of magnetic field.

Van Allen Probe Observations of Chorus Wave Activity, Source and Seed electrons, and the Radiation Belt Response During ICME and CIR Storms

NASA Astrophysics Data System (ADS)

Bingham, S.; Mouikis, C.; Kistler, L. M.; Farrugia, C. J.; Paulson, K. W.; Huang, C. L.; Boyd, A. J.; Spence, H. E.; Kletzing, C.

2017-12-01

Whistler mode chorus waves are electromagnetic waves that have been shown to be a major contributor to enhancements in the outer radiation belt during geomagnetic storms. The temperature anisotropy of source electrons (10s of keV) provides the free energy for chorus waves, which can accelerate sub-relativistic seed electrons (100s of keV) to relativistic energies. This study uses Van Allen Probe observations to examine the excitation and plasma conditions associated with chorus wave observations, the development of the seed population, and the outer radiation belt response in the inner magnetosphere, for 25 ICME and 35 CIR storms. Plasma data from the Helium Oxygen Proton Electron (HOPE) instrument and magnetic field measurements from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) are used to identify chorus wave activity and to model a linear theory based proxy for chorus wave growth. A superposed epoch analysis shows a peak of chorus wave power on the dawnside during the storm main phase that spreads towards noon during the storm recovery phase. According to the linear theory results, this wave activity is driven by the enhanced convection driving plasma sheet electrons across the dayside. Both ICME and CIR storms show comparable levels of wave growth. Plasma data from the Magnetic Electron Ion Spectrometer (MagEIS) and the Relativistic Electron Proton Telescope (REPT) are used to observe the seed and relativistic electrons. A superposed epoch analysis of seed and relativistic electrons vs. L shows radiation belt enhancements with much greater frequency in the ICME storms, coinciding with a much stronger and earlier seed electron enhancement in the ICME storms.

Suppression of laser phase noise in direct-detection optical OFDM transmission using phase-conjugated pilots

NASA Astrophysics Data System (ADS)

Zhang, Lu; Ming, Yi; Li, Jin

2017-11-01

Due to the unique phase noise (PN) characteristics in direct-detection optical OFDM (DDO-OFDM) systems, the design of PN compensator is considered as a difficult task. In this paper, a laser PN suppression scheme with low complexity for DDO-OFDM based on coherent superposition of data carrying subcarriers and their phase conjugates is proposed. Through theoretical derivation, the obvious PN suppression is observed. The effectiveness of this technique is demonstrated by simulation of a 4-QAM DDO-OFDM system over 1000 km transmission length at different laser line-width and subcarrier frequency spacing. The results show that the proposed scheme can significantly suppress both varied phase rotation term (PTR) and inter-carrier interference (ICI), and the laser line-width can be relaxed with up to 9 dB OSNR saving or even breakthrough of performance floor.

Red cell distribution width does not predict stroke severity or functional outcome.

PubMed

Ntaios, George; Gurer, Ozgur; Faouzi, Mohamed; Aubert, Carole; Michel, Patrik

2012-01-01

Red cell distribution width was recently identified as a predictor of cardiovascular and all-cause mortality in patients with previous stroke. Red cell distribution width is also higher in patients with stroke compared with those without. However, there are no data on the association of red cell distribution width, assessed during the acute phase of ischemic stroke, with stroke severity and functional outcome. In the present study, we sought to investigate this relationship and ascertain the main determinants of red cell distribution width in this population. We used data from the Acute Stroke Registry and Analysis of Lausanne for patients between January 2003 and December 2008. Red cell distribution width was generated at admission by the Sysmex XE-2100 automated cell counter from ethylene diamine tetraacetic acid blood samples stored at room temperature until measurement. An χ(2) -test was performed to compare frequencies of categorical variables between different red cell distribution width quartiles, and one-way analysis of variance for continuous variables. The effect of red cell distribution width on severity and functional outcome was investigated in univariate and multivariate robust regression analysis. Level of significance was set at 95%. There were 1504 patients (72±15·76 years, 43·9% females) included in the analysis. Red cell distribution width was significantly associated to NIHSS (β-value=0·24, P=0·01) and functional outcome (odds ratio=10·73 for poor outcome, P<0·001) at univariate analysis but not multivariate. Prehospital Rankin score (β=0·19, P<0·001), serum creatinine (β=0·008, P<0·001), hemoglobin (β=-0·009, P<0·001), mean platelet volume (β=0·09, P<0·05), age (β=0·02, P<0·001), low ejection fraction (β=0·66, P<0·001) and antihypertensive treatment (β=0·32, P<0·001) were independent determinants of red cell distribution width. Red cell distribution width, assessed during the early phase of acute ischemic stroke, does not predict severity or functional outcome. © 2011 The Authors. International Journal of Stroke © 2011 World Stroke Organization.

Seismogenic width controls aspect ratios of earthquake ruptures

NASA Astrophysics Data System (ADS)

Weng, Huihui; Yang, Hongfeng

2017-03-01

We investigate the effect of seismogenic width on aspect ratios of earthquake ruptures by using numerical simulations of strike-slip faulting and an energy balance criterion near rupture tips. If the seismogenic width is smaller than a critical value, then ruptures cannot break the entire fault, regardless of the size of the nucleation zone. The seismic moments of these self-arresting ruptures increase with the nucleation size, forming nucleation-related events. The aspect ratios increase with the seismogenic width but are smaller than 8. In contrast, ruptures become breakaway and tend to have high aspect ratios (>8) if the seismogenic width is sufficiently large. But the critical nucleation size is larger than the theoretical estimate for an unbounded fault. The eventual seismic moments of breakaway ruptures do not depend on the nucleation size. Our results suggest that estimating final earthquake magnitude from the nucleation phase may only be plausible on faults with small seismogenic width.

A Survey of Phase Space Density Radial Distribution of Relativistic Electrons During a 2-year Time Period (2001-2002)

NASA Astrophysics Data System (ADS)

Chen, Y.; Reeves, G.; Friedel, R. H.

2005-12-01

The source of relativistic electrons in the Earth's radiation belts in recovery phase of geomagnetic storms is still an open question which requires more observational analysis. To address this question, we first need to differentiate between two competing mechanisms, inward radial transport or in-situ energization. Recent work has focused on analysis of phase space density distribution for specific storms of interest. Here we expand on the results of earlier event studies by surveying the phase space density radial distribution and its temporal evolution during storms for a time period of 2 years (2001-2002). Data in this work are from the IES and HIST electron detectors on board POLAR, whose orbit crosses the outer part of outer radiation belt through equatorial plane almost every 18 hours during this period. The fact that detected electrons with given 1st and 2nd adiabatic invariants can cover L*~6-10, allows tracing the temporally evolving radial gradient which can help in determining the source of new electrons. Initial analysis of approximately 190 days suggests that the energization of relativistic electrons may result from a more complicated combination of radial transport and in-situ acceleration than is usually assumed.

High-speed three-dimensional shape measurement for dynamic scenes using bi-frequency tripolar pulse-width-modulation fringe projection

NASA Astrophysics Data System (ADS)

Zuo, Chao; Chen, Qian; Gu, Guohua; Feng, Shijie; Feng, Fangxiaoyu; Li, Rubin; Shen, Guochen

2013-08-01

This paper introduces a high-speed three-dimensional (3-D) shape measurement technique for dynamic scenes by using bi-frequency tripolar pulse-width-modulation (TPWM) fringe projection. Two wrapped phase maps with different wavelengths can be obtained simultaneously by our bi-frequency phase-shifting algorithm. Then the two phase maps are unwrapped using a simple look-up-table based number-theoretical approach. To guarantee the robustness of phase unwrapping as well as the high sinusoidality of projected patterns, TPWM technique is employed to generate ideal fringe patterns with slight defocus. We detailed our technique, including its principle, pattern design, and system setup. Several experiments on dynamic scenes were performed, verifying that our method can achieve a speed of 1250 frames per second for fast, dense, and accurate 3-D measurements.

Precambrian perspectives.

PubMed

Goodwin, A M

1981-07-03

The Precambrian record is interpreted in terms of an evolutionary progression that moves in the direction of increasing continental stability. An early, highly mobile microplate tectonics phase progressed through a more stable, largely intracratonic, ensialic, mobile belt phase to the modern macroplate tectonics phase that involves large, rigid lithospheric plates. Various phases are characterized by distinctive crustal associations. Three controls-bulk earth heat production, crustal fractionation and cratonization, and atmospheric oxygen accumulation-are viewed as the cumulative cause of the trends and events that characterize the crust at different stages of development, from its inception approximately 4.6 billion years ago to the present.

Penetration of Large Scale Electric Field to Inner Magnetosphere

NASA Astrophysics Data System (ADS)

Chen, S. H.; Fok, M. C. H.; Sibeck, D. G.; Wygant, J. R.; Spence, H. E.; Larsen, B.; Reeves, G. D.; Funsten, H. O.

2015-12-01

The direct penetration of large scale global electric field to the inner magnetosphere is a critical element in controlling how the background thermal plasma populates within the radiation belts. These plasma populations provide the source of particles and free energy needed for the generation and growth of various plasma waves that, at critical points of resonances in time and phase space, can scatter or energize radiation belt particles to regulate the flux level of the relativistic electrons in the system. At high geomagnetic activity levels, the distribution of large scale electric fields serves as an important indicator of how prevalence of strong wave-particle interactions extend over local times and radial distances. To understand the complex relationship between the global electric fields and thermal plasmas, particularly due to the ionospheric dynamo and the magnetospheric convection effects, and their relations to the geomagnetic activities, we analyze the electric field and cold plasma measurements from Van Allen Probes over more than two years period and simulate a geomagnetic storm event using Coupled Inner Magnetosphere-Ionosphere Model (CIMI). Our statistical analysis of the measurements from Van Allan Probes and CIMI simulations of the March 17, 2013 storm event indicate that: (1) Global dawn-dusk electric field can penetrate the inner magnetosphere inside the inner belt below L~2. (2) Stronger convections occurred in the dusk and midnight sectors than those in the noon and dawn sectors. (3) Strong convections at multiple locations exist at all activity levels but more complex at higher activity levels. (4) At the high activity levels, strongest convections occur in the midnight sectors at larger distances from the Earth and in the dusk sector at closer distances. (5) Two plasma populations of distinct ion temperature isotropies divided at L-Shell ~2, indicating distinct heating mechanisms between inner and outer radiation belts. (6) CIMI simulations reveal alternating penetration and shielding electric fields during the main phase of the geomagnetic storm, indicating an impulsive nature of the large scale penetrating electric field in regulating the gain and loss of radiation belt particles. We will present the statistical analysis and simulations results.

Igneous and tectonic evolution of the Batchawana Greenstone Belt, Superior Province: a U-Pb zircon and titanite study

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

Corfu, F.; Grunsky, E.C.

1987-01-01

U-Pb isotopic dating of zircon and titanite from all the major litho-tectonic units of the Batchawana belt, an Archean greenstone belt of the Abitibi Subprovince of the Superior Province in Canada, shows that the belt evolved during a period of about 60 Ma between about 2730 and 2670 Ma ago. Subsequent deformation of the supracrustal sequences produced isoclinal folding and culminated in metamorphism ranging from lower greenschist to amphibolite facies and anatexis related to the intrusion of syn- to late-tectonic plutons, four phases of which have ages of 2678 +4/-2 Ma, 2677 +/- 2 Ma, 2677 +/- 3 Ma, andmore » 2676 +/- 2 Ma. Two post-tectonic granitoid plutons in the center of the belt were intruded 2674 +/- 3 Ma and 2673 +/- 5 Ma ago and were followed by the emplacement of a composite mafic to felsic intrusion; a monzonite and a hornblendite from this intrusion yield identical ages of 2668 +/- 2 Ma. Titanite ages are identical or younger than the ages of coexisting zircons and reflect regional metamorphism and post-tectonic plutonism, but in a few cases they are younger and may record increased fluid activity along faults and the intrusion of mafic dikes. U-Pb zircon systematics, together with age and lithological relationships, suggests that the greenstone belt formed in an oceanic environment from material derived initially mainly from the mantle. Subsequent melting at the base of the thickening volcanic succession produced intermediate to felsic volcanic rocks, tonalites, and later granodioritic to granitic plutons leading to the final consolidation of the granite-greenstone terrain. 47 references.« less

Cenozoic structural evolution, thermal history, and erosion of the Ukrainian Carpathians fold-thrust belt

NASA Astrophysics Data System (ADS)

Nakapelyukh, Mykhaylo; Bubniak, Ihor; Bubniak, Andriy; Jonckheere, Raymond; Ratschbacher, Lothar

2018-01-01

The Carpathians are part of the Alpine-Carpathian-Dinaridic orogen surrounding the Pannonian basin. Their Ukrainian part constitutes an ancient subduction-accretion complex that evolved into a foreland fold-thrust belt with a shortening history that was perpendicular to the orogenic strike. Herein, we constrain the evolution of the Ukrainian part of the Carpathian fold-thrust belt by apatite fission-track dating of sedimentary and volcanic samples and cross-section balancing and restoration. The apatite fission-track ages are uniform in the inner―southwestern part of the fold-thrust belt, implying post-shortening erosion since 12-10 Ma. The ages in the leading and trailing edges record provenance, i.e., sources in the Trans-European suture zone and the Inner Carpathians, respectively, and show that these parts of the fold-thrust were not heated to more than 100 °C. Syn-orogenic strata show sediment recycling: in the interior of the fold-thrust belt―the most thickened and most deeply eroded nappes―the apatite ages were reset, eroded, and redeposited in the syn-orogenic strata closer to the fore- and hinterland; the lag times are only a few million years. Two balanced cross sections, one constructed for this study and based on field and subsurface data, reveal an architecture characterized by nappe stacks separated by high-displacement thrusts; they record 340-390 km shortening. A kinematic forward model highlights the fold-thrust belt evolution from the pre-contractional configuration over the intermediate geometries during folding and thrusting and the post-shortening, erosional-unloading configuration at 12-10 Ma to the present-day geometry. Average shortening rates between 32-20 Ma and 20-12 Ma amounted to 13 and 21 km/Ma, respectively, implying a two-phased deformation of the Ukrainian fold-thrust belt.

What (maybe) you do not know about radiation belts

NASA Astrophysics Data System (ADS)

Boscher, D. M.; Sicard-Piet, A.; Rolland, G.

2013-12-01

As observed by several authors, the outer electron radiation belt reacts globally to the solar cycle. This is well known. Their trend at very low L shells is less known. Using NOAA POES 0° detector between L=1.16 and 1.18, we discovered a factor 10 increase of the 30-300keV electron flux in the declining phase of the solar cycle. It was observed in 2003, using SEM-2 detector on board POES 15, but the same trend was observed in 1983 and in 1991-1992 using the old SEM detector on the NOAA LEO satellites. Protons in the same range of energy (50-500keV) exhibits a similar behaviour. The second proton belt has been highlighted by the USAF-NASA CRRES satellite. Such proton belt was observed a few times in the past ( in 1963 by McIlwain, in February 1986 by Gussenhoven et al.), but if the good energy range is observed, this can appear several times in a solar cycle. We will show measurements of 10 MeV protons on board the SSO satellite SAC-C, showing the dynamics of the proton belt following the events of March and November 2001, October-November 2003 and September 2005. The NASA AP8 proton model is limited to 300MeV. Is it a physical limitation or simply a question of signal to noise limitation at the time this model was developed? Using old NOAA satellites which have on board a very high energy detector (HEPAD), we will show trapped particles at energies not far from 1GeV. This was measured during several years, from 1979 to 1986, showing the long beating of the belt with the solar cycle.

A marching-walking hybrid induces step length adaptation and transfers to natural walking

PubMed Central

Long, Andrew W.; Finley, James M.

2015-01-01

Walking is highly adaptable to new demands and environments. We have previously studied adaptation of locomotor patterns via a split-belt treadmill, where subjects learn to walk with one foot moving faster than the other. Subjects learn to adapt their walking pattern by changing the location (spatial) and time (temporal) of foot placement. Here we asked whether we can induce adaptation of a specific walking pattern when one limb does not “walk” but instead marches in place (i.e., marching-walking hybrid). The marching leg's movement is limited during the stance phase, and thus certain sensory signals important for walking may be reduced. We hypothesized that this would produce a spatial-temporal strategy different from that of normal split-belt adaptation. Healthy subjects performed two experiments to determine whether they could adapt their spatial-temporal pattern of step lengths during the marching-walking hybrid and whether the learning transfers to over ground walking. Results showed that the hybrid group did adapt their step lengths, but the time course of adaptation and deadaption was slower than that for the split-belt group. We also observed that the hybrid group utilized a mostly spatial strategy whereas the split-belt group utilized both spatial and temporal strategies. Surprisingly, we found no significant difference between the hybrid and split-belt groups in over ground transfer. Moreover, the hybrid group retained more of the learned pattern when they returned to the treadmill. These findings suggest that physical rehabilitation with this marching-walking paradigm on conventional treadmills may produce changes in symmetry comparable to what is observed during split-belt training. PMID:25867742

Characteristics of pitch angle distributions of hundreds of keV electrons in the slot region and inner radiation belt

NASA Astrophysics Data System (ADS)

Zhao, H.; Li, X.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Baker, D. N.; Jaynes, A. N.; Malaspina, D. M.

2014-12-01

The pitch angle distribution (PAD) of energetic electrons in the slot region and inner radiation belt received little attention in the past decades due to the lack of quality measurements. Using the state-of-the-art pitch angle-resolved data from the Magnetic Electron Ion Spectrometer instrument onboard the Van Allen Probes, a detailed analysis of hundreds of keV electron PADs below L = 4 is performed, in which the PADs are categorized into three types: normal (flux peaking at 90°), cap (exceedingly peaking narrowly around 90°), and 90° minimum (lower flux at 90°) PADs. By examining the characteristics of the PADs of ˜460 keV electrons for over a year, we find that the 90° minimum PADs are generally present in the inner belt (L<2), while normal PADs dominate at L˜3.5-4. In the region between, 90° minimum PADs dominate during injection times and normal PADs dominate during quiet times. Cap PADs appear mostly at the decay phase of storms in the slot region and are likely caused by the pitch angle scattering of hiss waves. Fitting the normal PADs into sinnα form, the parameter n is much higher below L = 3 than that in the outer belt and relatively constant in the inner belt but changes significantly in the slot region (2 < L < 3) during injection times. As for the 90° minimum PADs, by performing a detailed case study, we find in the slot region this type of PAD is likely caused by chorus wave heating, but this mechanism can hardly explain the formation of 90° minimum PADs at the center of inner belt.

A marching-walking hybrid induces step length adaptation and transfers to natural walking.

PubMed

Long, Andrew W; Finley, James M; Bastian, Amy J

2015-06-01

Walking is highly adaptable to new demands and environments. We have previously studied adaptation of locomotor patterns via a split-belt treadmill, where subjects learn to walk with one foot moving faster than the other. Subjects learn to adapt their walking pattern by changing the location (spatial) and time (temporal) of foot placement. Here we asked whether we can induce adaptation of a specific walking pattern when one limb does not "walk" but instead marches in place (i.e., marching-walking hybrid). The marching leg's movement is limited during the stance phase, and thus certain sensory signals important for walking may be reduced. We hypothesized that this would produce a spatial-temporal strategy different from that of normal split-belt adaptation. Healthy subjects performed two experiments to determine whether they could adapt their spatial-temporal pattern of step lengths during the marching-walking hybrid and whether the learning transfers to over ground walking. Results showed that the hybrid group did adapt their step lengths, but the time course of adaptation and deadaption was slower than that for the split-belt group. We also observed that the hybrid group utilized a mostly spatial strategy whereas the split-belt group utilized both spatial and temporal strategies. Surprisingly, we found no significant difference between the hybrid and split-belt groups in over ground transfer. Moreover, the hybrid group retained more of the learned pattern when they returned to the treadmill. These findings suggest that physical rehabilitation with this marching-walking paradigm on conventional treadmills may produce changes in symmetry comparable to what is observed during split-belt training. Copyright © 2015 the American Physiological Society.

Structural development and stress evolution of an arcuate fold-and-thrust system, southwestern Greater Caucasus, Republic of Georgia

NASA Astrophysics Data System (ADS)

Tibaldi, A.; Bonali, F. L.; Russo, E.; Pasquarè Mariotto, F. A.

2018-05-01

The southern front of the Greater Caucasus is quite rectilinear in plan view, with the exception of part of the Rioni Basin, where marine and continental deposits of Cretaceous-Neogene age were locally folded and uplifted; this resulted in the formation of an arcuate fold-and-thrust system that extends 45 km into the foreland. Although previous studies suggested that this system has developed only since Miocene times, our new detailed and systematic field measurements of brittle and ductile structures show a very complex history, consisting in four main phases of brittle deformation and folding, dated from Eocene to Quaternary times. We collected microtectonic data at 248 faults, and calculated the related paleostress tensors. The first two phases which we document here, predated folding and were characterised by dominant transcurrent faulting and subordinate reverse motions; the greatest principal stress σ1 was perpendicular and later parallel to the mountain belt. Afterwards, NW-SE, E-W and NE-SW trending, south-vergent asymmetrical folds started to form. In the western sector of the study area, folds are sinuous in plan view, whereas to the east they show a left-stepping, en-échelon geometry. Another two, brittle deformation phases took place after the folding, due to the activity of a set of right-lateral, strike-slip faults that strike NW-SE and NE-SW, respectively, as well as by left-lateral strike-slip faults, mostly striking NW-SE, NE-SW and NNE-SSW. These two additional phases were produced by a NE-SW to N-S trending σ1. The arcuate belt is marked by along-strike variations in the tectonic regime and deformation geometry, plus belt-parallel stretching. Based on our field data, integrated with published analogue models, we suggest a possible explanation for the Rioni structure, in terms of the oblique, asymmetric indentation of an upper crustal blocks moving to the SSW.

From micron to mountain-scale, using accessory phase petrochronology to quantify the rates of deformation in the Himalaya and beyond

NASA Astrophysics Data System (ADS)

Mottram, C. M.

2016-12-01

Mountains form where the Earth's plates collide; during this upheaval rocks are deformed by massive forces. The rates and timescales over which these deformational processes occur are determined from tiny accessory minerals that record geological time through radioactive decay. However, there remain major unresolved challenges in using chemical and microstructural markers to link the dates yielded from these accessory phases to specific deformation events and discerning the effects of deformation on the isotopic and elemental tracers in these phases. Here, the chemical signatures and deformation textures from micron-scale accessory phases are used to decode the record of mountain belt-scale deformational processes encrypted in the rocks. The Himalayan orogen is used as an ideal natural laboratory to understand the chemical processes that have modified the Earth's crust during orogenesis. Combined laser ablation split-stream U-Th-Pb and REE analysis of deformed monazite and titanite, along with Electron BackScatter Diffraction (EBSD) imaging and Pressure-Temperature (P-T) phase equilibria modelling are used to: (1) link accessory phase `age' to `metamorphic stage'; (2) to quantify the influence of deformation on monazite (re)crystallisation mechanisms and its subsequent effect on the crystallographic structure, ages and trace-element distribution in individual grains; and (3) understand how deformation is accommodated through different chemical and structural processes that operate at varying scales through time. This study highlights the importance of fully integrating the pressure-temperature-time-deformation history of multiple accessory phases to better interpret the deformational history of the cores of evolving mountain belts.

Changes in the Width of the Tibiofibular Syndesmosis Related to Lower Extremity Joint Dynamics and Neuromuscular Coordination on Drop Landing During the Menstrual Cycle.

PubMed

Okazaki, Michie; Kaneko, Masaaki; Ishida, Yukisato; Murase, Norio; Katsumura, Toshihito

2017-09-01

Many injuries of the lower extremities, especially the knee and ankle, occur during sports activity, and the incidence rate is higher in women than in men. The hypothesis was that phases of the menstrual cycle affect the width of the tibiofibular syndesmosis during drop landing in healthy young women and that such changes at the tibiofibular joint also affect the dynamics and neuromuscular coordination of the lower extremities. Descriptive laboratory study. Participants included 28 healthy young women (mean age, 21.0 ± 0.8 years). Blood samples were collected to determine plasma levels of estradiol and progesterone immediately before the performance of the task: drop landing on a single leg from a 30-cm platform. Using ultrasonography, the distance between the tibia and the distal end of the fibula, regarded as the width of the tibiofibular syndesmosis, was measured in an upright position without flexion of the ankle. The peak ground-reaction force (GRF) on landing was measured using a force platform. The time to peak GRF (Tp-GRF) was measured as the time from initial ground contact to the peak GRF. Hip, knee, and ankle joint angles during the single-leg landing were calculated using a 3-dimensional motion analysis system. Muscle activities of the lower extremities were measured using surface electromyography. The width of the tibiofibular syndesmosis was significantly greater in the luteal phase when compared with the menstrual, follicular, and ovulation phases (by 5%-8% of control). Also, during the luteal phase, the Tp-GRF was significantly shorter than in the follicular phase (by 6%); hip internal rotation and knee valgus were significantly greater than in the menstrual phase (by 43% and 34%, respectively); knee flexion was significantly less than in the menstrual and follicular phases (by 7%-9%); ankle dorsiflection was significantly less than in the follicular phase (by 11%); ankle adduction and eversion were significantly greater than in the menstrual and follicular phases (by 26%-46%, and 27%-33%, respectively); and activation of the gluteus maximus before landing was significantly lower than in the menstrual and follicular phases (by 20%-22%). The luteal phase appears to be associated with decreased strength and laxity of the ankle as well as lower extremity muscle activity in women. The changes presumably represent a greater risk for sports injuries. The results of this study suggest that the luteal phase may be related to the greater incidence of lower extremity injuries in women.

Restoration of Late Neoarchean-Early Cambrian tectonics in the Rengali orogen and its environs (eastern India): The Antarctic connection

NASA Astrophysics Data System (ADS)

Bhattacharya, A.; Das, H. H.; Bell, Elizabeth; Bhattacharya, Atreyee; Chatterjee, N.; Saha, L.; Dutt, A.

2016-10-01

Geological mapping and P-T path reconstructions are combined with monazite chemical age and Secondary Ion Mass Spectrometric (SIMS) U-Pb zircon age determinations to identify crustal domains with distinctive evolutionary histories in the Rengali orogen sandwiched between two Grenvillian-age metamorphic belts, i.e. the Eastern Ghats Granulite Belt (EGGB) in the south, and the amphibolite facies Gangpur Schist Belt (GSB) in the north, which in turn forms a collar along the NW/W margins of the Paleo/Mesoarchean Singhbhum Craton (SC) north of the Rengali orogen. Anatectic gneisses in the orogen core exhibit multi-phase Neoarchean/Paleoproterozoic deformation, metamorphic P-T histories and juvenile magma emplacement events. The high-grade belt is inferred to be a septum of the Bastar Craton (BC). The flanking supracrustal belt in the orogen - dominated by quartz-muscovite schists (± staurolite, kyanite, garnet pyrophyllite), inter-bedded with poorly-sorted and polymict meta-conglomerate, and meta-ultramafic/amphibolite bands - evolved along P-T paths characterized by sub-greenschist to amphibolite facies peak P-T conditions in closely-spaced samples. The supracrustal rocks and the anatectic gneisses of contrasting metamorphic P-T histories experienced D1, D2 and D3 fabric-forming events, but the high-angle obliquity between the steeply-plunging D3 folds in the anatectic gneisses and the gently-plunging D3 folds in the supracrustal unit suggests the two lithodemic units were tectonically accreted post-S2. The supracrustal belt is inferred to be a tectonic mélange formed in an accretionary wedge at the tri-junction of the Bastar Craton, the Eastern Ghats Granulite Belt and the Singhbhum Craton; the basin closure synchronous with the assembly of EGGB and the Singhbhum Craton-Gangpur Schist belt composite occurred between 510 and 610 Ma. Based on the available evidence across the facing coastlines of the Greater India landmass and the Australo-Antarctic blocks at 500 Ma, it is suggested that the EGGB welded with the Greater India landmass during the Pan African along an accretion zone, of which the Rengali orogen is a part, synchronous with the final assembly of the Gondwanaland.

A statistical approach to determining energetic outer radiation belt electron precipitation fluxes

NASA Astrophysics Data System (ADS)

Simon Wedlund, Mea; Clilverd, Mark A.; Rodger, Craig J.; Cresswell-Moorcock, Kathy; Cobbett, Neil; Breen, Paul; Danskin, Donald; Spanswick, Emma; Rodriguez, Juan V.

2014-05-01

Subionospheric radio wave data from an Antarctic-Arctic Radiation-Belt (Dynamic) Deposition VLF Atmospheric Research Konsortia (AARDDVARK) receiver located in Churchill, Canada, is analyzed to determine the characteristics of electron precipitation into the atmosphere over the range 3 < L < 7. The study advances previous work by combining signals from two U.S. transmitters from 20 July to 20 August 2010, allowing error estimates of derived electron precipitation fluxes to be calculated, including the application of time-varying electron energy spectral gradients. Electron precipitation observations from the NOAA POES satellites and a ground-based riometer provide intercomparison and context for the AARDDVARK measurements. AARDDVARK radiowave propagation data showed responses suggesting energetic electron precipitation from the outer radiation belt starting 27 July 2010 and lasting ~20 days. The uncertainty in >30 keV precipitation flux determined by the AARDDVARK technique was found to be ±10%. Peak >30 keV precipitation fluxes of AARDDVARK-derived precipitation flux during the main and recovery phase of the largest geomagnetic storm, which started on 4 August 2010, were >105 el cm-2 s-1 sr-1. The largest fluxes observed by AARDDVARK occurred on the dayside and were delayed by several days from the start of the geomagnetic disturbance. During the main phase of the disturbances, nightside fluxes were dominant. Significant differences in flux estimates between POES, AARDDVARK, and the riometer were found after the main phase of the largest disturbance, with evidence provided to suggest that >700 keV electron precipitation was occurring. Currently the presence of such relativistic electron precipitation introduces some uncertainty in the analysis of AARDDVARK data, given the assumption of a power law electron precipitation spectrum.

NASA's RBSP-ECT Science Investigation of the Van Allen Probes Mission: Highlights of the Prime Mission Phase, Data Access Overview, and Opportunities to Collaborate in the Extended Mission Phase

NASA Astrophysics Data System (ADS)

Smith, S. S.; Friedel, R. H.; Larsen, B.; Reeves, G.; Spence, H. E.

2015-12-01

In this poster, we present a summary of access to the data products of the Radiation Belt Storm Probes - Energetic Particle Composition, and Thermal plasma (RBSP-ECT) suite of NASA's Van Allen Probes mission. The RBSP-ECT science investigation (http://rbsp-ect.sr.unh.edu) measures comprehensively the near-Earth charged particle environment in order to understand the processes that control the acceleration, global distribution, and variability of radiation belt electrons and ions. RBSP-ECT data products derive from the three instrument elements that comprise the suite, which collectively covers the broad energies that define the source and seed populations, the core radiation belts, and also their highest energy ultra-relativistic extensions. These RBSP-ECT instruments include, from lowest to highest energies: the Helium, Oxygen, Proton, and Electron (HOPE) sensor, the Magnetic Electron and Ion Spectrometer (MagEIS), and the Relativistic Electron and Proton Telescope (REPT). We provide a brief overview of their principles of operation, as well as a description of the Level 2-3 data products that the HOPE, MagEIS, and REPT instruments produce, both separately and together. We provide a summary of how to access these RBSP-ECT data products at our Science Operation Center and Science Data Center (http://www.rbsp-ect.lanl.gov/rbsp_ect.php ) as well as caveats for their use. Finally, in the spirit of efficiently and effectively promoting and encouraging new collaborations, we present a summary of past publications, current studies, and opportunities for your future participation in RBSP-ECT extended mission phase science.

Coordination of Septate Junctions Assembly and Completion of Cytokinesis in Proliferative Epithelial Tissues.

PubMed

Daniel, Emeline; Daudé, Marion; Kolotuev, Irina; Charish, Kristi; Auld, Vanessa; Le Borgne, Roland

2018-05-07

How permeability barrier function is maintained when epithelial cells divide is largely unknown. Here, we have investigated how the bicellular septate junctions (BSJs) and tricellular septate junctions (TSJs) are remodeled throughout completion of cytokinesis in Drosophila epithelia. We report that, following cytokinetic ring constriction, the midbody assembles, matures within SJs, and is displaced basally in two phases. In a first slow phase, the neighboring cells remain connected to the dividing cells by means of SJ-containing membrane protrusions pointing to the maturing midbody. Fluorescence recovery after photobleaching (FRAP) experiments revealed that SJs within the membrane protrusions correspond to the old SJs that were present prior to cytokinesis. In contrast, new SJs are assembled below the adherens junctions and spread basally to build a new belt of SJs in a manner analogous to a conveyor belt. Loss of function of a core BSJ component, the Na+/K+-ATPase pump Nervana 2 subunit, revealed that the apical-to-basal spread of BSJs drives the basal displacement of the midbody. In contrast, loss of the TSJ protein Bark beetle indicated that remodeling of TSJs is rate limiting and slowed down midbody migration. In the second phase, once the belt of SJs is assembled, the basal displacement of the midbody is accelerated and ultimately leads to abscission. This last step is temporally uncoupled from the remodeling of SJs. We propose that cytokinesis in epithelia involves the coordinated polarized assembly and remodeling of SJs both in the dividing cell and its neighbors to ensure the maintenance of permeability barrier integrity in proliferative epithelia. Copyright © 2018 Elsevier Ltd. All rights reserved.

Understanding the mechanisms of radiation belt dropouts observed by Van Allen Probes

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

Xiang, Zheng; Tu, Weichao; Li, Xinlin

To achieve a better understanding of the dominant loss mechanisms for the rapid dropouts of radiation belt electrons, three distinct radiation belt dropout events observed by Van Allen Probes are comprehensively investigated. For each event, observations of the pitch angle distribution of electron fluxes and electromagnetic ion cyclotron (EMIC) waves are analyzed to determine the effects of atmospheric precipitation loss due to pitch angle scattering induced by EMIC waves. Last closed drift shells (LCDS) and magnetopause standoff position are obtained to evaluate the effects of magnetopause shadowing loss. Evolution of electron phase space density (PSD) versus L* profiles and themore » μ and K (first and second adiabatic invariants) dependence of the electron PSD drops are calculated to further analyze the dominant loss mechanisms at different L*. Here, our findings suggest that these radiation belt dropouts can be classified into distinct classes in terms of dominant loss mechanisms: magnetopause shadowing dominant, EMIC wave scattering dominant, and combination of both mechanisms. Different from previous understanding, our results show that magnetopause shadowing can deplete electrons at L* < 4, while EMIC waves can efficiently scatter electrons at L* > 4. Compared to the magnetopause standoff position, it is more reliable to use LCDS to evaluate the impact of magnetopause shadowing. Finally, the evolution of electron PSD versus L* profile and the μ, K dependence of electron PSD drops can provide critical and credible clues regarding the mechanisms responsible for electron losses at different L* over the outer radiation belt.« less

Multi-satellite simultaneous observations of magnetopause and atmospheric losses of radiation belt electrons during an intense solar wind dynamic pressure pulse

DOE PAGES

Xiang, Zheng; Ni, Binbin; Zhou, Chen; ...

2016-05-03

Radiation belt electron flux dropouts are a kind of drastic variation in the Earth's magnetosphere, understanding of which is of both scientific and societal importance. We report multi-satellite simultaneous observations of magnetopause and atmospheric losses of radiation belt electrons during an event of intense solar wind dynamic pressure pulse, using electron flux data from a group of 14 satellites. Moreover, when the pulse occurred, magnetopause and atmospheric loss could take effect concurrently contributing to the electron flux dropout. Losses through the magnetopause were observed to be efficient and significant at L ≳ 5, owing to the magnetopause intrusion into Lmore » ~6 and outward radial diffusion associated with sharp negative gradient in electron phase space density. Losses to the atmosphere were directly identified from the precipitating electron flux observations, for which pitch angle scattering by plasma waves could be mainly responsible. While the convection and substorm injections strongly enhanced the energetic electron fluxes up to hundreds of keV, they could delay other than avoid the occurrence of electron flux dropout at these energies. Finally, we demonstrate that the pulse-time radiation belt electron flux dropout depends strongly on the specific interplanetary and magnetospheric conditions and that losses through the magnetopause and to the atmosphere and enhancements of substorm injection play an essential role in combination, which should be incorporated as a whole into future simulations for comprehending the nature of radiation belt electron flux dropouts.« less

Understanding the Mechanisms of Radiation Belt Dropouts Observed by Van Allen Probes

NASA Astrophysics Data System (ADS)

Xiang, Zheng; Tu, Weichao; Li, Xinlin; Ni, Binbin; Morley, S. K.; Baker, D. N.

2017-10-01

To achieve a better understanding of the dominant loss mechanisms for the rapid dropouts of radiation belt electrons, three distinct radiation belt dropout events observed by Van Allen Probes are comprehensively investigated. For each event, observations of the pitch angle distribution of electron fluxes and electromagnetic ion cyclotron (EMIC) waves are analyzed to determine the effects of atmospheric precipitation loss due to pitch angle scattering induced by EMIC waves. Last closed drift shells (LCDS) and magnetopause standoff position are obtained to evaluate the effects of magnetopause shadowing loss. Evolution of electron phase space density (PSD) versus L* profiles and the μ and K (first and second adiabatic invariants) dependence of the electron PSD drops are calculated to further analyze the dominant loss mechanisms at different L*. Our findings suggest that these radiation belt dropouts can be classified into distinct classes in terms of dominant loss mechanisms: magnetopause shadowing dominant, EMIC wave scattering dominant, and combination of both mechanisms. Different from previous understanding, our results show that magnetopause shadowing can deplete electrons at L* < 4, while EMIC waves can efficiently scatter electrons at L* > 4. Compared to the magnetopause standoff position, it is more reliable to use LCDS to evaluate the impact of magnetopause shadowing. The evolution of electron PSD versus L* profile and the μ, K dependence of electron PSD drops can provide critical and credible clues regarding the mechanisms responsible for electron losses at different L* over the outer radiation belt.

The Comprehensive Inner Magnetosphere-Ionosphere Model

NASA Technical Reports Server (NTRS)

Fok, M.-C.; Buzulukova, N. Y.; Chen, S.-H.; Glocer, A.; Nagai, T.; Valek, P.; Perez, J. D.

2014-01-01

Simulation studies of the Earth's radiation belts and ring current are very useful in understanding the acceleration, transport, and loss of energetic particles. Recently, the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model were merged to form a Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. CIMI solves for many essential quantities in the inner magnetosphere, including ion and electron distributions in the ring current and radiation belts, plasmaspheric density, Region 2 currents, convection potential, and precipitation in the ionosphere. It incorporates whistler mode chorus and hiss wave diffusion of energetic electrons in energy, pitch angle, and cross terms. CIMI thus represents a comprehensive model that considers the effects of the ring current and plasmasphere on the radiation belts. We have performed a CIMI simulation for the storm on 5-9 April 2010 and then compared our results with data from the Two Wide-angle Imaging Neutral-atom Spectrometers and Akebono satellites. We identify the dominant energization and loss processes for the ring current and radiation belts. We find that the interactions with the whistler mode chorus waves are the main cause of the flux increase of MeV electrons during the recovery phase of this particular storm. When a self-consistent electric field from the CRCM is used, the enhancement of MeV electrons is higher than when an empirical convection model is applied. We also demonstrate how CIMI can be a powerful tool for analyzing and interpreting data from the new Van Allen Probes mission.

Motor vehicle seat belt restraint system analysis during rollover.

PubMed

Meyer, Steven E; Hock, Davis; Forrest, Stephen; Herbst, Brian; Sances, Anthony; Kumaresan, Srirangam

2003-01-01

The multi-planar and multiple impact long duration accident sequence of a real world rollover results in multidirectional vehicle acceleration pulses and multiplanar occupant motions not typically seen in a planar crash sequence. Various researchers have documented that, while contemporary production emergency locking seatbelt retractors (ELRs) have been found to be extremely effective in the planar crashes in which they are extensively evaluated, when subjected to multi-planar acceleration environments their response may be different than expected. Specifically, accelerations in the vertical plane have been shown to substantially affect the timeliness of the retractors inertial sensor moving out of its neutral position and locking the seat belt. An analysis of the vehicle occupant motions relative to the acceleration pulses sensed at the retractor location indicates a time phase shift that, under certain circumstances, can result in unexpected seat belt spool out and occupant excursions in these multi-planar, multiple impact crash sequences. This paper will review the various previous studies focusing on the retractors response to these multidirectional, including vertical, acceleration environments and review statistical studies based upon U.S. government collected data indicating a significant difference in belt usage rates in rollover accidents as compared to all other planar accident modes. A significant number of real world accident case studies will be reviewed wherein the performance of ELR equipped seatbelt systems spooled out. Finally, the typical occupant injury and the associated mechanism due to belt spool out in real world accidents will be delineated.

Understanding the mechanisms of radiation belt dropouts observed by Van Allen Probes

DOE PAGES

Xiang, Zheng; Tu, Weichao; Li, Xinlin; ...

2017-08-30

To achieve a better understanding of the dominant loss mechanisms for the rapid dropouts of radiation belt electrons, three distinct radiation belt dropout events observed by Van Allen Probes are comprehensively investigated. For each event, observations of the pitch angle distribution of electron fluxes and electromagnetic ion cyclotron (EMIC) waves are analyzed to determine the effects of atmospheric precipitation loss due to pitch angle scattering induced by EMIC waves. Last closed drift shells (LCDS) and magnetopause standoff position are obtained to evaluate the effects of magnetopause shadowing loss. Evolution of electron phase space density (PSD) versus L* profiles and themore » μ and K (first and second adiabatic invariants) dependence of the electron PSD drops are calculated to further analyze the dominant loss mechanisms at different L*. Here, our findings suggest that these radiation belt dropouts can be classified into distinct classes in terms of dominant loss mechanisms: magnetopause shadowing dominant, EMIC wave scattering dominant, and combination of both mechanisms. Different from previous understanding, our results show that magnetopause shadowing can deplete electrons at L* < 4, while EMIC waves can efficiently scatter electrons at L* > 4. Compared to the magnetopause standoff position, it is more reliable to use LCDS to evaluate the impact of magnetopause shadowing. Finally, the evolution of electron PSD versus L* profile and the μ, K dependence of electron PSD drops can provide critical and credible clues regarding the mechanisms responsible for electron losses at different L* over the outer radiation belt.« less

Method and apparatus for pulse width modulation control of an AC induction motor

DOEpatents

Geppert, Steven; Slicker, James M.

1984-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

Method and apparatus for pulse width modulation control of an AC induction motor

NASA Technical Reports Server (NTRS)

Geppert, Steven (Inventor); Slicker, James M. (Inventor)

1984-01-01

An inverter is connected between a source of DC power and a three-phase AC induction motor, and a micro-processor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .THETA., where .THETA. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands of electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

Manufacturing Methods for Cutting, Machining and Drilling Composites. Volume 1. Composites Machining Handbook

DTIC Science & Technology

1978-08-01

12°±30’ 1180±2° OPTIONAL .0005 IN./IN. BACK TAPER 015 RAD LIPS TO BE WITHIN .002 OF TRUE ANGULAR POSITION NOTES: 1. LAND WIDTH: 28% ± .005... horoscope and dye-penetrant requirements. 79 PHASE 1 PHASE II PHASE III PHASE IV CUTTING DRILLING MACHINING NONDESTRUCTIVE EVALUATION METHOD MATERIAL

ALMA observations of the η Corvi debris disc: inward scattering of CO-rich exocomets by a chain of 3-30 M⊕ planets?

NASA Astrophysics Data System (ADS)

Marino, S.; Wyatt, M. C.; Panić, O.; Matrà, L.; Kennedy, G. M.; Bonsor, A.; Kral, Q.; Dent, W. R. F.; Duchene, G.; Wilner, D.; Lisse, C. M.; Lestrade, J.-F.; Matthews, B.

2017-03-01

While most of the known debris discs present cold dust at tens of astronomical unit (au), a few young systems exhibit hot dust analogous to the Zodiacal dust. η Corvi is particularly interesting as it is old and it has both, with its hot dust significantly exceeding the maximum luminosity of an in situ collisional cascade. Previous work suggested that this system could be undergoing an event similar to the Late Heavy Bombardment (LHB) soon after or during a dynamical instability. Here, we present ALMA observations of η Corvi with a resolution of 1.2 arcsec (∼22 au) to study its outer belt. The continuum emission is consistent with an axisymmetric belt, with a mean radius of 152 au and radial full width at half-maximum of 46 au, which is too narrow compared to models of inward scattering of an LHB-like scenario. Instead, the hot dust could be explained as material passed inwards in a rather stable planetary configuration. We also report a 4σ detection of CO at ∼20 au. CO could be released in situ from icy planetesimals being passed in when crossing the H2O or CO2 ice lines. Finally, we place constraints on hidden planets in the disc. If a planet is sculpting the disc's inner edge, this should be orbiting at 75-100 au, with a mass of 3-30 M⊕ and an eccentricity <0.08. Such a planet would be able to clear its chaotic zone on a time-scale shorter than the age of the system and scatter material inwards from the outer belt to the inner regions, thus feeding the hot dust.

Short belt-like Ca 2 B 2 O 5 ·H 2 O nanostructures: Hydrothermal formation, FT-IR, thermal decomposition, and optical properties

NASA Astrophysics Data System (ADS)

Zhu, Wancheng; Zhang, Xiao; Wang, Xiaoli; Zhang, Heng; Zhang, Qiang; Xiang, Lan

2011-10-01

Uniform high crystallinity short belt-like Ca 2B 2O 5·H 2O nanostructures (nanobelts) were facilely synthesized through a room temperature coprecipitation of CaCl 2, H 3BO 3, and NaOH solutions, followed by a mild hydrothermal treatment (180 °C, 12.0 h). By a preferential growth parallel to the (1 0 0) planes, Ca 2B 2O 5·H 2O nanobelts with a length of 1-5 μm, a width of 100-400 nm, and a thickness of 55-90 nm were obtained. The calcination of the nanobelts at 500 °C for 2.0 h led to short Ca 2B 2O 5 nanobelts with well preserved 1D morphology. Calcination at 800 °C led to a mixture of Ca 2B 2O 5 and Ca 3B 2O 6. The products were with belt-like and quasi-polyhedron morphology, while they turned into pore-free micro-rod like and polyhedron morphology when the calcination was taken in the presence of NaCl. NaCl assisted high temperature calcination at 900 °C promoted the formation of Ca 3B 2O 6 in the products. When dispersed in deionized water or absolute ethanol, the Ca 2B 2O 5·H 2O nanobelts and Ca 2B 2O 5 nanobelts showed good transparency from the ultraviolet to the visible region. The as-synthesized Ca 2B 2O 5·H 2O and Ca 2B 2O 5 nanobelts can be employed as novel metal borate nanomaterials for further potential applications in the area of glass fibers, antiwear additive, ceramic coatings, and so on.

Jupiter's Deep Cloud Structure Revealed Using Keck Observations of Spectrally Resolved Line Shapes

NASA Technical Reports Server (NTRS)

Bjoraker, G. L.; Wong, M.H.; de Pater, I.; Adamkovics, M.

2015-01-01

Technique: We present a method to determine the pressure at which significant cloud opacity is present between 2 and 6 bars on Jupiter. We use: a) the strength of a Fraunhofer absorption line in a zone to determine the ratio of reflected sunlight to thermal emission, and b) pressure- broadened line profiles of deuterated methane (CH3D) at 4.66 meters to determine the location of clouds. We use radiative transfer models to constrain the altitude region of both the solar and thermal components of Jupiter's 5-meter spectrum. Results: For nearly all latitudes on Jupiter the thermal component is large enough to constrain the deep cloud structure even when upper clouds are present. We find that Hot Spots, belts, and high latitudes have broader line profiles than do zones. Radiative transfer models show that Hot Spots in the North and South Equatorial Belts (NEB, SEB) typically do not have opaque clouds at pressures greater than 2 bars. The South Tropical Zone (STZ) at 32 degrees South has an opaque cloud top between 4 and 5 bars. From thermochemical models this must be a water cloud. We measured the variation of the equivalent width of CH3D with latitude for comparison with Jupiter's belt-zone structure. We also constrained the vertical profile of H2O in an SEB Hot Spot and in the STZ. The Hot Spot is very dry for a probability less than 4.5 bars and then follows the H2O profile observed by the Galileo Probe. The STZ has a saturated H2O profile above its cloud top between 4 and 5 bars.

The Lamu Basin deepwater fold-and-thrust belt: An example of a margin-scale, gravity-driven thrust belt along the continental passive margin of East Africa

NASA Astrophysics Data System (ADS)

Cruciani, Francesco; Barchi, Massimiliano R.

2016-03-01

In recent decades, advances in seismic processing and acquisition of new data sets have revealed the presence of many deepwater fold-and-thrust belts (DW-FTBs), often developing along continental passive margins. These kinds of tectonic features have been intensively studied, due to their substantial interest. This work presents a regional-scale study of the poorly explored Lamu Basin DW-FTB, a margin-scale, gravity-driven system extending for more than 450 km along the continental passive margin of Kenya and southern Somalia (East Africa). A 2-D seismic data set was analyzed, consisting of both recently acquired high-quality data and old reprocessed seismic profiles, for the first detailed structural and stratigraphic interpretation of this DW-FTB. The system originated over an Early to mid-Cretaceous shale detachment due to a mainly gravity-spreading mechanism. Analysis of synkinematic strata indicates that the DW-FTB was active from the Late Cretaceous to the Early Miocene, but almost all of the deformation occurred before the Late Paleocene. The fold-and-thrust system displays a marked N-S variation in width, the northern portion being more than 150 km wide and the southern portion only a few dozen kilometers wide; this along-strike variation is thought to be related to the complex tectonosedimentary evolution of the continental margin at the Somalia-Kenya boundary, also reflected in the present-day bathymetry. Locally, a series of volcanic edifices stopped the basinward propagation of the DW-FTB. A landward change in the dominant structural style, from asymmetric imbricate thrust sheets to pseudo-symmetric detachment folds, is generally observed, related to the landward thickening of the detached shales.

The Seebeck coefficient of superionic conductors

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

Mahan, G. D.

2015-01-28

We present a theory of the anomalous Seebeck coefficient found in the superionic conductor Cu{sub 2}Se. It has a phase transition at T = 400 K where the cations disorder but the anions do not. This disorder gives a temperature-dependent width to the electronic states in the conduction band. This width provides the anomalous Seebeck contribution.

3D crustal structure of the Alpine belt and foreland basins as imaged by ambient-noise surface wave

NASA Astrophysics Data System (ADS)

Molinari, Irene; Morelli, Andrea; Cardi, Riccardo; Boschi, Lapo; Poli, Piero; Kissling, Edi

2016-04-01

We derive a 3-D crustal structure (S wave velocity) underneath northern Italy and the wider Alpine region, from an extensive data set of measurements of Rayleigh-wave phase- and group-velocities from ambient noise correlation among all seismographic stations available to date in the region, via a constrained tomographic inversion made to honor detailed active source reflection/refraction profiles and other geological information. We first derive a regional-scale surface wave tomography from ambient-noise-based phase- and group- surface wave velocity observations (Verbeke et al., 2012). Our regional 3D model (Molinari et al., 2015) shows the low velocity area beneath the Po Plain and the Molasse basin; the contrast between the low-velocity crust of the Adriatic domain and the high-velocity crust of the Tyrrhenian domain is clearly seen, as well as an almost uniform crystalline crust beneath the Alpine belt. However, higher frequency data can be exploited to achieve higher resolution images of the Po Plain and Alpine foreland 3D crustal structure. We collected and analyze one year of noise records (2011) of ~100 North Italy seismic broadband stations, we derive the Green functions between each couple of stations and we measure the phase- and group-Rayleigh wave velocity. We conduct a suite of linear least squares inversion of both phase- and group-velocity data, resulting in 2-D maps of Rayleigh-wave phase and group velocity at periods between 3 and 40s with a resolution of 0.1x0.1 degrees. The maps are then inverted to get the 3D structure with unprecedented details. We present here our results, we compare them with other studies, and we discuss geological/geodynamical implications. We believe that such a model stands for the most up-to-date seismological information on the crustal structure of the Alpine belt and foreland basins, and it can represent a reliable reference for further, more detailed, studies to come, based on the high seismograph station density being accomplished by the AlpArray project.

Photometric Observations and Analysis of 1082 Pirola

NASA Astrophysics Data System (ADS)

Baker, Ronald E.; Pilcher, Frederick; Benishek, Vladimir

2011-04-01

CCD observations of the main-belt asteroid 1082 Pirola were recorded during the period 2010 October to 2011 January. Analysis of the lightcurve found a synodic period of P = 15.8525 ± 0.0005 h and amplitude A = 0.53 ± 0.01 mag. The phase curve referenced to mean magnitude suggests the absolute magnitude and phase slope parameter: H = 10.507 ± 0.014 mag; G = 0.080 ± 0.016. The phase curve referenced to maximum light suggests: H = 10.320 ± 0.013 mag; G = 0.107 ± 0.016.

Simulations of electrically induced particle structuring on spherical drop surface

NASA Astrophysics Data System (ADS)

Hu, Yi; Vlahovska, Petia; Miksis, Michael

2016-11-01

Recent experiments (Ouriemi and Vlahovska, 2014) show intriguing surface patterns when a uniform electric field is applied to a droplet covered with colloidal particles. Depending on the particle properties and the electrical field intensity, particles organize into an equatorial belt, pole-to-pole chains, or dynamic vortices. Here we present a model to simulate the collective particle dynamics, which accounts for the electrohydrodynamic flow and particle dielectrophoresis due to the non-uniformity of local electrical field. In stronger electric fields, particles are expected to undergo Quincke rotation, inducing rotating clusters through inter-particle hydrodynamical interaction. We discuss how the field intensity influences the width, orientation and periodicity of the particle clusters. Our results provide insight into the various particle assembles discovered in the experiments.

Lead burdens and behavioral impairments of the lined shore crab Pachygrapsus crassipes

USGS Publications Warehouse

Hui, Clifford A.

2002-01-01

Unless a correction is made, population estimates derived from a sample of belt transects will be biased if a fraction of, the individuals on the sample transects are not counted. An approach, useful for correcting this bias when sampling immotile populations using transects of a fixed width, is presented. The method assumes that a searcher's ability to find objects near the center of the transect is nearly perfect. The method utilizes a mathematical equation, estimated from the data, to represent the searcher's inability to find all objects at increasing distances from the center of the transect. An example of the analysis of data, formation of the equation, and application is presented using waterfowl nesting data collected in Colorado.

A model-based exploration of the role of pattern generating circuits during locomotor adaptation.

PubMed

Marjaninejad, Ali; Finley, James M

2016-08-01

In this study, we used a model-based approach to explore the potential contributions of central pattern generating circuits (CPGs) during adaptation to external perturbations during locomotion. We constructed a neuromechanical modeled of locomotion using a reduced-phase CPG controller and an inverted pendulum mechanical model. Two different forms of locomotor adaptation were examined in this study: split-belt treadmill adaptation and adaptation to a unilateral, elastic force field. For each simulation, we first examined the effects of phase resetting and varying the model's initial conditions on the resulting adaptation. After evaluating the effect of phase resetting on the adaptation of step length symmetry, we examined the extent to which the results from these simple models could explain previous experimental observations. We found that adaptation of step length symmetry during split-belt treadmill walking could be reproduced using our model, but this model failed to replicate patterns of adaptation observed in response to force field perturbations. Given that spinal animal models can adapt to both of these types of perturbations, our findings suggest that there may be distinct features of pattern generating circuits that mediate each form of adaptation.

Characterisation of Australian Verdelho wines from the Queensland Granite Belt region.

PubMed

Sonni, Francesca; Moore, Evan G; Chinnici, Fabio; Riponi, Claudio; Smyth, Heather E

2016-04-01

Verdelho is a white-grape-vine, growing well in the Granite Belt region of Queensland. Despite its traditional use in Madeira wine production, there is scant literature on the flavour characteristics of this variety as a dry wine. In this work, for the first time, volatile compounds of Verdelho wines from the Granite Belt have been isolated by solid phase extraction (SPE), and analysed using gas chromatography-mass spectrometry (GC-MS). A corresponding sensory characterisation of this distinctive wine style has also been investigated, using sensory descriptive analysis. Chemical compounds that mostly contribute to the flavour of these wines were related to fruity sweet notes (ethyl esters and acetates), grassy notes (3-hexenol), floral aromas (2-phenylethanol and β-linalool) and cheesy aromas (fatty acids). Sensory analysis confirmed that the Verdelho wines were characterised by fruity aroma attributes, especially "tree-fruit" and "rockmelon", together with "herbaceous", while significant differences in the other attributes were found. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prompt Recovery and Enhancement of the Earth's Outer Radiation Belt due to Relativistic Electron Injections

NASA Astrophysics Data System (ADS)

Tang, C. L.; Zhang, J.; Reeves, G. D.; Baker, D. N.; Spence, H. E.; Funsten, H. O.; Blake, J. B.

2015-12-01

We present multipoint observations (RBSP, GEOS and THEMIS) of the substorm electron injections during the substorm event on 16 August 2013. RBSP-A detected the MeV electron phase space density increased by an order of magnitude in about one hour at L* > 5.0. At L* = 4.4, the injected MeV electrons were also detected. It is suggested that the magnetic field dipolarization associated with the substorm injections alone can explain that the prompt recovery and enhancements of the relativistic electron (~ MeV) fluxes in the outer radiation belt. The observations of THEMIS-A also first presented that the near-Earth magnetotail at substorm onset is important in the MeV electron injection event: the enhanced fluxes of ~200 keV electrons are the source population and intense electromagnetic pulses are the driving source of MeV injected electrons. The pulse model is used to explain the dispersionless MeV injected electrons in the outer radiation belt observed by GEOS-13 and RBSP-A.

Earthward penetration of Pc 4-5 waves and radiation belt electron enhancements during geospace magnetic storms

NASA Astrophysics Data System (ADS)

Daglis, I. A.; Georgiou, M.; Zesta, E.; Balasis, G.; Tsinganos, K.

2013-12-01

This paper addresses the question whether radiation belt electron enhancements are associated with ultra-low frequency (ULF) wave power penetrating to lower L-shells during intense geospace magnetic storms. We have examined the variation of relativistic electron fluxes in the inner magnetosphere during small, moderate, and intense storms and have compared them with concurrent variations of the power of Pc 4-5 waves, using multi-point wave observations from the IMAGE and CARISMA ground-based magnetometer arrays. We discuss the excitation, growth and decay characteristics of Pc 4-5 waves during the different phases of the three classes of magnetic storms, with particular emphasis on the distribution of wave power over a range of L shells. The work leading to this paper has received funding from the European Union's Seventh Framework Programme (FP7-SPACE-2011-1) under grant agreement no. 284520 for the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project.

Fine Structure of Plasmaspheric Hiss

NASA Astrophysics Data System (ADS)

Summers, D.; Omura, Y.; Nakamura, S.; Kletzing, C.

2014-12-01

Plasmaspheric hiss plays a key role in controlling the structure and dynamics of Earth's radiation belts.The quiet time slot region between the inner and outer belts can be explained as a steady-state balance between earthward radial diffusion and pitch-angle scattering loss of energetic electrons to the atmosphere induced by plasmaspheric hiss. Plasmaspheric hiss can also induce gradual precipitation loss of MeV electrons from the outer radiation belt. Plasmaspheric hiss has been widely regarded as a broadband,structureless,incoherent emission. Here, by examining burst-mode vector waveform data from the EMFISIS instrument on the Van Allen Probes mission,we show that plasmaspheric hiss is a coherent emission with complex fine structure. Specifically, plasmaspheric hiss appears as discrete rising tone and falling tone elements. By means of waveform analysis we identify typical amplitudes,phase profiles,and sweep rates of the rising and falling tone elements. The new observations reported here can be expected to fuel a re-examination of the properties of plasmaspheric hiss, including a further re-analysis of the generation mechanism for hiss.

Interstellar Explorer Observations of the Solar System's Debris Disks

NASA Astrophysics Data System (ADS)

Lisse, C. M.; McNutt, R. L., Jr.; Brandt, P. C.

2017-12-01

Planetesimal belts and debris disks full of dust are known as the "signposts of planet formation" in exosystems. The overall brightness of a disk provides information on the amount of sourcing planetesimal material, while asymmetries in the shape of the disk can be used to search for perturbing planets. The solar system is known to house two such belts, the Asteroid belt and the Kuiper Belt; and at least one debris cloud, the Zodiacal Cloud, sourced by planetisimal collisions and Kuiper Belt comet evaporative sublimation. However these are poorly understood in toto because we live inside of them. E.g., while we know of the two planetesimal belt systems, it is not clear how much, if any, dust is produced from the Kuiper belt since the near-Sun comet contributions dominate near-Earth space. Understanding how much dust is produced in the Kuiper belt would give us a much better idea of the total number of bodies in the belt, especially the smallest ones, and their dynamical collisional state. Even for the close in Zodiacal cloud, questions remain concerning its overall shape and orientation with respect to the ecliptic and invariable planes of the solar system - they aren't explainable from the perturbations caused by the known planets alone. In this paper we explore the possibilities of using an Interstellar Explorer telescope placed at 200 AU from the sun to observe the brightness, shape, and extent of the solar system's debris disk(s). We should be able to measure the entire extent of the inner, near-earth zodiacal cloud; whether it connects smoothly into an outer cloud, or if there is a second outer cloud sourced by the Kuiper belt and isolated by the outer planets, as predicted by Stark & Kuchner (2009, 2010) and Poppe et al. (2012, 2016; Figure 1). VISNIR imagery will inform about the dust cloud's density, while MIR cameras will provide thermal imaging photometry related to the cloud's dust particle size and composition. Observing at high phase angle by looking back towards the sun from 200 AU, we will be able to perform deep searches for the presence of rings and dust clouds around discrete sources, and thus we will be able to search for possible strong individual sources of the debris clouds - like the Haumea family collisional fragments, or the rings of the Centaur Chariklo, or dust emitted from spallation off the 6 known bodies of the Pluto system.

Origin and implications of non-radial Imbrium Sculpture on the Moon

DOE PAGES

Schultz, Peter H.; Crawford, David A.

2016-07-20

Rimmed grooves, lineations and elongate craters around Mare Imbrium shape much of the nearside Moon. This pattern was coined the Imbrium Sculpture 1, and it was originally argued that it must have been formed by a giant oblique (~30°) impact, a conclusion echoed by later studies 2. Some investigators, however, noticed that many elements of the Imbrium Sculpture are not radial to Imbrium, thereby implicating an endogenic or structural origin 3, 4. Here we use these non-radial trends to conclude that the Imbrium impactor was a proto-planet (half the diameter of Vesta), once part of a population of large proto-planetsmore » in the asteroid belt. Such independent constraints on the sizes of the Imbrium and other basin-forming impactors markedly increase estimates for the mass in the asteroid belt before depletion caused by the orbital migration of Jupiter and Saturn 5. Furthermore, laboratory impact experiments, shock physics codes and the groove widths indicate that multiple fragments (up to 2% of the initial diameter) from each oblique basin-forming impactor, such as the one that formed Imbrium, should have survived planetary collisions and contributed to the heavy impact bombardment between 4.3 and 3.8 billion years ago.« less

Abundance of the reef-building Petaloconchus varians (Gastropoda: Vermetidae) on intertidal rocky shores at Ilha Grande Bay, southeastern Brazil.

PubMed

Breves, André; Széchy, Maria Teresa M DE; Lavrado, Helena P; Junqueira, Andrea O R

2017-01-01

The reef-building vermetid Petaloconchus varians occurs in the western Atlantic Ocean, from the Caribbean Sea to the southern coast of Brazil. The present study evaluated the abundance of P. varians on intertidal rocky shores in Ilha Grande Bay (Rio de Janeiro State), and characterized their reefs, describing the species density, besides the weight and the belt width of the reefs. Petaloconchus varians reefs were recorded at 25 sites, with rocky shores exposed to different wave action (very sheltered, sheltered, semi-exposed and exposed) and slopes (10° to 46°). Clusters of individuals constructed large reefs along the middle intertidal zone, creating a wide belt (38 cm to 2 m). The density of P. varians and the weight of the reefs ranged from 620 to 2,559 ind.100 cm-2 and from 100 to 1,500 g.100 cm-2, respectively. Considering that the species was last reported from the area in the mid-20th century, the present study suggests that P. varians reefs are becoming dominant in the intertidal zone of rocky shores in Ilha Grande Bay. This is a contribution to knowledge of this ecosystem in Ilha Grande Bay, in view of local or global ecological changes.

Constraining Seismic Structure of Upper-Mantle Discontinuities: A New Approach Using High-Frequency Triplication Data

NASA Astrophysics Data System (ADS)

Ishii, M.; Park, S.

2016-12-01

Constraining elastic properties of the 410- and 660-km discontinuities is crucial for understanding the mantle composition and dynamics. One approach to study the transition zone is to use the "triplicated" arrivals of seismic data. These arrivals consist of three seismic phases that are sensitive to seismic structure slightly above, at, and below the discontinuity. Thus, these data are powerful tools in providing constraints on the depth and velocity jump of the discontinuities with consequences for the studies of mantle composition and relevant phase transitions. One of the most challenging aspects of using the triplication data, however, is to identify the three individual phases that arrive close in time. In order to separate the three phases, we apply Radon transform to short-period seismograms recorded by a dense array of stations. This approach unwraps the triplication pattern, and brings out the high-frequency information that is not easily accessible in the original form of data. Subsequent modeling of the unwrapped data allows velocity jump, depth, and width of the discontinuities to be obtained. This method is applied to study the transition zone around the Kuril subduction zone, a region northeast of Japan. We take advantage of the High-Sensitivity Seismograph Network in Japan that consists of more than 700 stations. These stations provide dense sampling in distance that allows us to capture the triplication pattern. The wave speeds immediately above and below the 410- and 660-km discontinuities as well as their depths and widths are constrained. In general, both discontinuities are depressed compared to the global average, and exhibit finite widths. The width estimates have implications on effects such as the existence of water or melt, and garnet transformations occurring at similar depths as the post-spinel transition.

On the Connection Between Microbursts and Nonlinear Electronic Structures in Planetary Radiation Belts

NASA Technical Reports Server (NTRS)

Osmane, Adnane; Wilson, Lynn B., III; Blum, Lauren; Pulkkinen, Tuija I.

2016-01-01

Using a dynamical-system approach, we have investigated the efficiency of large-amplitude whistler waves for causing microburst precipitation in planetary radiation belts by modeling the microburst energy and particle fluxes produced as a result of nonlinear wave-particle interactions. We show that wave parameters, consistent with large amplitude oblique whistlers, can commonly generate microbursts of electrons with hundreds of keV-energies as a result of Landau trapping. Relativistic microbursts (greater than 1 MeV) can also be generated by a similar mechanism, but require waves with large propagation angles Theta (sub k)B greater than 50 degrees and phase-speeds v(sub phi) greater than or equal to c/9. Using our result for precipitating density and energy fluxes, we argue that holes in the distribution function of electrons near the magnetic mirror point can result in the generation of double layers and electron solitary holes consistent in scales (of the order of Debye lengths) to nonlinear structures observed in the radiation belts by the Van Allen Probes. Our results indicate a relationship between nonlinear electrostatic and electromagnetic structures in the dynamics of planetary radiation belts and their role in the cyclical production of energetic electrons (E greater than or equal to 100 keV) on kinetic timescales, which is much faster than previously inferred.

The Radiation Belt Electron Scattering by Magnetosonic Wave: Dependence on Key Parameters

NASA Astrophysics Data System (ADS)

Lei, Mingda; Xie, Lun; Li, Jinxing; Pu, Zuyin; Fu, Suiyan; Ni, Binbin; Hua, Man; Chen, Lunjin; Li, Wen

2017-12-01

Magnetosonic (MS) waves have been found capable of creating radiation belt electron butterfly distributions in the inner magnetosphere. To investigate the physical nature of the interactions between radiation belt electrons and MS waves, and to explore a preferential condition for MS waves to scatter electrons efficiently, we performed a comprehensive parametric study of MS wave-electron interactions using test particle simulations. The diffusion coefficients simulated by varying the MS wave frequency show that the scattering effect of MS waves is frequency insensitive at low harmonics (f < 20 fcp), which has great implications on modeling the electron scattering caused by MS waves with harmonic structures. The electron scattering caused by MS waves is very sensitive to wave normal angles, and MS waves with off 90° wave normal angles scatter electrons more efficiently. By simulating the diffusion coefficients and the electron phase space density evolution at different L shells under different plasma environment circumstances, we find that MS waves can readily produce electron butterfly distributions in the inner part of the plasmasphere where the ratio of electron plasma-to-gyrofrequency (fpe/fce) is large, while they may essentially form a two-peak distribution outside the plasmapause and in the inner radiation belt where fpe/fce is small.

Spectroscopy of five V-type asteroids in the middle and outer main belt

NASA Astrophysics Data System (ADS)

Migliorini, Alessandra; De Sanctis, M. C.; Lazzaro, D.; Ammannito, E.

2018-03-01

The origin of basaltic asteroids found in the middle and outer main belt is an open question. These asteroids are not dynamically linked to the Vesta collisional family and can be the remnants of other large differentiated asteroids present in the early phases of the main belt but destroyed long ago. Spectroscopic investigation of some V-type asteroids in the middle-outer belt, classified as such by their SLOAN photometric colours (Ivezić et al.) and WISE albedos (Masiero et al.), has revealed that their spectra are more similar to other taxonomic classes, like -Q, R, S, or A (Jasmim et al. and Oszkiewicz et al.). Here, we report about the observation, in the near-infrared spectral range, of five V-type asteroids located beyond 2.5 au. These observations allowed us to infer their taxonomic classification. Two asteroids, (21238) Panarea (observed in a previous campaign but here included for comparison) and (105041) 2000 KO41, confirm their basaltic nature. For asteroids (10800) 1992 OM8 and (15898) Kharasterteam a taxonomic classification is more uncertain, being either Q- or S-type. Asteroid (14390) 1990 QP10 classification is difficult to ascribe to the known taxonomic classes, maybe due to the low-quality spectrum. Further observations are desirable for this asteroid.

Radar Observations of Asteroids 7 Iris, 9 Metis, 12 Victoria, 216 Kleopatra, and 654 Zelinda

NASA Technical Reports Server (NTRS)

Mitchell, David L.; Ostro, Steven J.; Rosema, Keith D.; Hudson, R. Scott; Campbell, Donald B.; Chandler, John F.; Shapiro, Irwin I.

1995-01-01

We report 13-cm wavelength radar observations of the main-belt asteroids 7 Iris, 9 Metis, 12 Victoria, 216 Kleopatra, and 654 Zelinda obtained at Arecibo between 1980 and 1989. The echoes are highly polarized yet broadly distributed in Doppler frequency, indicating that our targets are smooth on decimeter scales but very rough on some scale(s) larger than about I m. The echo spectra are generally consistent with existing size, shape, and spin information based on radiometric, lightcurve, and occultation data. All of our targets possess distinctive radar signatures that reveal large- scale topography. Reflectivity spikes within narrow ranges of rotation phase suggest large flat regions on Iris, Metis, and Zelinda, while bimodal spectra imply nonconvex, possibly bifurcated shapes for Kleopatra and Victoria. Kleopatra has the highest radar albedo yet measured for a main-belt asteroid, indicating a high metal concentration and making Kleopatra the best main-belt candidate for a core remnant of a differentiated and subsequently disrupted parent body. Upon completion of the Arecibo telescope upgrade, there will be several opportunities per year to resolve main-belt asteroids with hundreds of delay-Doppler cells, which can be inverted to provide estimates of both three-dimensional shape and radar scattering properties.

Propagation properties of cylindrical sinc Gaussian beam

NASA Astrophysics Data System (ADS)

Eyyuboğlu, Halil T.; Bayraktar, Mert

2016-09-01

We investigate the propagation properties of cylindrical sinc Gaussian beam in turbulent atmosphere. Since an analytic solution is hardly derivable, the study is carried out with the aid of random phase screens. Evolutions of the beam intensity profile, beam size and kurtosis parameter are analysed. It is found that on the source plane, cylindrical sinc Gaussian beam has a dark hollow appearance, where the side lobes also start to emerge with increase in width parameter and Gaussian source size. During propagation, beams with small width and Gaussian source size exhibit off-axis behaviour, losing the dark hollow shape, accumulating the intensity asymmetrically on one side, whereas those with large width and Gaussian source size retain dark hollow appearance even at long propagation distances. It is seen that the beams with large widths expand more in beam size than the ones with small widths. The structure constant values chosen do not seem to alter this situation. The kurtosis parameters of the beams having small widths are seen to be larger than the ones with the small widths. Again the choice of the structure constant does not change this trend.

Motivation of employers to encourage their employees to use safety belts (phase 2).

DOT National Transportation Integrated Search

1983-08-01

An employer manual is developed which offers guidelines for the elements of a successful safety bell program. The guidelines are based upon the model developed as a result of site visits to successful programs and synthesis of expert opinion. A needs...

Tectono-metamorphic evolution of the Kibuye-Gitarama-Gatumba area (Rwanda): using petrochronology to unravel the geodynamic framework of the Karagwe-Ankole Belt

NASA Astrophysics Data System (ADS)

Van Daele, Johanna; Jacques, Dominique; Hulsbosch, Niels; Dewaele, Stijn; Muchez, Philippe

2017-04-01

The Mesoproterozoic Karagwe-Ankole Belt (KAB) extends from Burundi over Rwanda and NW-Tanzania to S-Uganda (Central Africa). The integration of the metamorphic and magmatic evolution of this orogenic belt in a consistent geodynamic framework is still controversial. Additionally, geochronological information on the deformation phases is limited. This tectono-metamorphic model is, however, a crucial component in the understanding of the Meso- to Early Neoproterozoic mineralization processes. A detailed structural mapping of road and river transects was performed in the Kibuye-Gitarama-Gatumba area (West Rwanda) to determine the deformation history of the KAB. Structural analyses and petrographic studies identified two main compressive deformation phases. A locally observed foliation with a N45W-N50W orientation is interpreted as the consequence of a first compressional phase (D1, shortening direction N40E-N45E). Additionally, a well-developed crenulation cleavage and a regionally pervasive foliation were found. The cleavage and foliation have an orientation of N20W-N30W (exceptionally N20E) and are indicative of a second compressional phase (D2) with an EW shortening direction. Final extension (D3) along a N30W-N10E direction resulted in boudinage and joint development. Fieldwork observations combined with known ages of the granites in the KAB indicate that D1 and D2 took place prior to 986 Ma while D3 is younger than 986 Ma. Based on thin section petrography, a petrochronological strategy was outlined to fill in the gaps of the currently broadly defined timeframe. The regional metamorphic grade of the study area is upper greenschist, with the formation of muscovite, biotite, chlorite, garnet, staurolite and cordierite. The main penetrative tectonic foliations (D1 and D2) are expressed by the preferential orientation of muscovite or biotite. In some cases, muscovite growing along the crenulation cleavage (syn-D2) was observed. Furthermore, pre- and syn-D2 garnets were identified. Different generations of quartz veins (post-dating D3) contain muscovite, garnet and/or biotite. These minerals provide excellent dating possibilities (Ar-Ar, in-situ Rb-Sr and Sm-Nd). The obtained results will be used to refine the chronological aspects of the deformation history of the KAB. Furthermore, these data will be combined with regional structural data, petrographic and geothermobarometric analyses to reconstruct the tectono-metamorphic evolution of the Karagwe-Ankole Belt, which will allow to obtain a better insight in the geodynamic evolution and the ore-forming processes.

Flux and polarization signals of spatially inhomogeneous gaseous exoplanets

NASA Astrophysics Data System (ADS)

Karalidi, T.; Stam, D. M.; Guirado, D.

2013-07-01

Aims: We present numerically calculated, disk-integrated, spectropolarimetric signals of starlight that is reflected by vertically and horizontally inhomogeneous gaseous exoplanets. We include various spatial features that are present on Solar System's gaseous planets: belts and zones, cyclonic spots, and polar hazes, to test whether such features leave traces in the disk-integrated fux and polarization signals. Methods: Broadband flux and polarization signals of starlight that is reflected by gaseous exoplanets are calculated using an efficient, adding-doubling radiative transfer code, that fully includes single and multiple scattering and polarization. The planetary model atmospheres are vertically inhomogeneous and can be horizontally inhomogeneous, and contain gas molecules and/or cloud and/or aerosol particles. Results: The broadband flux and polarization signals are sensitive to cloud top pressures, although in the presence of local pressure differences, such as in belts and clouds, the flux and polarization phase functions have similar shapes as those of horizontally homogeneous planets. Fitting flux phase functions of a planet with belts and zones using a horizontally homogeneous planet could theoretically yield cloud top pressures that differ by a few hundred mbar from those derived from fitting polarization phase functions. In practice, however, observational errors and uncertainties in cloud properties would make such a fit unreliable. A cyclonic spot like Jupiter's Great Red Spot, covering a few percent of the disk, located in equatorial regions, and rotating in and out of the observer's view yields a temporal variation of a few percent in the broadband flux and a few percent in the degree of polarization. Polar hazes leave strong traces in the polarization of reflected starlight in spatially resolved observations, especially seen at phase angles near 90°. Integrated across the planetary disk, polar hazes that cover only part of the planetary disk, change the broadband degree of polarization of the reflected light by a few percent. Such hazes have only small effects on locally reflected broadband fluxes and negligible effects on disk-integrated broadband fluxes. Conclusions: Deriving the presence of belts and zones in the atmospheres of gaseous exoplanets from broadband flux and polarization observations will be extremely difficult. Cyclonic spots could leave temporal changes in the broadband flux and polarization signals of a few percent. Polar hazes that cover a fraction of the planetary disk, and that are composed of small, Rayleigh scattering particles, change the broadband degree of polarization by at most a few percent.

Effects of pacing magnitudes and forms on bistability width in a modeled ventricular tissue

NASA Astrophysics Data System (ADS)

Huang, Xiaodong; Liu, Xuemei; Zheng, Lixian; Mi, Yuanyuan; Qian, Yu

2013-07-01

Bistability in periodically paced cardiac tissue is relevant to cardiac arrhythmias and its control. In the present paper, one-dimensional tissue of the phase I Luo-Rudy model is numerically investigated. The effects of various parameters of pacing signals on bistability width are studied. The following conclusions are obtained: (i) Pacing can be classified into two types: pulsatile and sinusoidal types. Pulsatile pacing reduces bistability width as its magnitude is increased. Sinusoidal pacing increases the width as its amplitude is increased. (ii) In a pacing period the hyperpolarizing part plays a more important role than the depolarizing part. Variations of the hyperpolarizing ratio in a period evidently change the width of bistability and its variation tendency. (iii) A dynamical mechanism is proposed to qualitatively explain the phenomena, which reveals the reason for the different effects of pulsatile and sinusoidal pacing on bistability. The methods for changing bistability width by external pacing may help control arrhythmias in cardiology.

Mixing efficiency inside micro-droplets coalesced by two components in cross-structure

NASA Astrophysics Data System (ADS)

Ren, Yanlin; Liu, Zhaomiao; Pang, Yan

2017-11-01

The mixing of micro-droplets is used in analytical chemistry, medicine production and material synthesis owing to its advantages including the encapsulation and narrow time residence distribution. In this work, droplets are coalesced by two dispersed phase with different flow rates, generated in cross-structure and mixed in planar serpentine structure. The mixing efficiency of micro-droplets under control characters including the width of entrance and the flow rate of dispersed phases have been investigated by experiments and numerical simulations. The UDS (user-defined scalar) as dimensionless concentration of the solution is adopted in simulation, and is used to calculate the concentration and the mixing effect. By changing the flow rates and the entrances` width, the changing rules of the mixing characters have been obtained. The asymmetry distributions of components make rapid mixing process in half part of each droplet when travel through a straight channel. Increasing of the ratio of entrance width result into larger droplet and weaken the chaotic mixing effect. Meanwhile, the coalesced mechanism can be performed by ranging the ratio of flow rates, the ranges are also determined by the widths of entrances. The authors gratefully acknowledge the support of National Natural Science Foundation of China (Grant No. 11572013).

PARTITIONING OF PERFLUOROOCTANOATE INTO PHOSPHATIDYLCHOLINE BILAYERS IS CHAIN LENGTH-INDEPENDENT

PubMed Central

Xie, Wei; Bothun, Geoffrey D.; Lehmler, Hans-Joachim

2010-01-01

The chain length dependence of the interaction of PFOA, a persistent environmental contaminant, with dimyristoyl- (DMPC), dipalmitoyl- (DPPC) and distearoylphosphatidylcholine (DSPC) was investigated using steady-state fluorescence anisotropy spectroscopy, differential scanning calorimetry (DSC) and dynamic light scattering (DLS). PFOA caused a linear depression of the main phase transition temperature Tm while increasing the width of the phase transition of all three phosphatidylcholines. Although PFOA’s effect on the on Tm and the transition width decreased in the order DMPC > DPPC > DSPC, its relative effect on the phase behavior was largely independent of the phosphatidylcholine. PFOA caused swelling of DMPC but not DPPC and DSPC liposomes at 37°C in the DLS experiments, which suggests that PFOA partitions more readily into bilayers in the fluid phase. These findings suggest that PFOA’s effect on the phase behavior of phosphatidylcholines depends on the cooperativity and state (i.e., gel versus liquid phase) of the membrane. DLS experiments are also consistent with partial liposome solubilization at PFOA/lipid molar ratios > 1, which suggests the formation of mixed PFOA-lipid micelles. PMID:20096277

Sensorless Modeling of Varying Pulse Width Modulator Resolutions in Three-Phase Induction Motors

PubMed Central

Marko, Matthew David; Shevach, Glenn

2017-01-01

A sensorless algorithm was developed to predict rotor speeds in an electric three-phase induction motor. This sensorless model requires a measurement of the stator currents and voltages, and the rotor speed is predicted accurately without any mechanical measurement of the rotor speed. A model of an electric vehicle undergoing acceleration was built, and the sensorless prediction of the simulation rotor speed was determined to be robust even in the presence of fluctuating motor parameters and significant sensor errors. Studies were conducted for varying pulse width modulator resolutions, and the sensorless model was accurate for all resolutions of sinusoidal voltage functions. PMID:28076418

Sensorless Modeling of Varying Pulse Width Modulator Resolutions in Three-Phase Induction Motors.

PubMed

Marko, Matthew David; Shevach, Glenn

2017-01-01

A sensorless algorithm was developed to predict rotor speeds in an electric three-phase induction motor. This sensorless model requires a measurement of the stator currents and voltages, and the rotor speed is predicted accurately without any mechanical measurement of the rotor speed. A model of an electric vehicle undergoing acceleration was built, and the sensorless prediction of the simulation rotor speed was determined to be robust even in the presence of fluctuating motor parameters and significant sensor errors. Studies were conducted for varying pulse width modulator resolutions, and the sensorless model was accurate for all resolutions of sinusoidal voltage functions.

Influence of slot number and pole number in fault-tolerant brushless dc motors having unequal tooth widths

NASA Astrophysics Data System (ADS)

Ishak, D.; Zhu, Z. Q.; Howe, D.

2005-05-01

The electromagnetic performance of fault-tolerant three-phase permanent magnet brushless dc motors, in which the wound teeth are wider than the unwound teeth and their tooth tips span approximately one pole pitch and which have similar numbers of slots and poles, is investigated. It is shown that they have a more trapezoidal phase back-emf wave form, a higher torque capability, and a lower torque ripple than similar fault-tolerant machines with equal tooth widths. However, these benefits gradually diminish as the pole number is increased, due to the effect of interpole leakage flux.

Complex local Moho topography in the Western Carpathians: Indication of the ALCAPA and the European Plate contact

NASA Astrophysics Data System (ADS)

Hrubcová, Pavla; Środa, Piotr

2015-01-01

Seismic data from deep refraction and wide-angle reflection profiles intersecting the Western Carpathians show distinct upper-mantle Pn phases with anomalous apparent velocities identified in the first and later arrivals. Their systematic analysis indicates that such phases are present in numerous seismic sections both for in-line and off-line shots. They are observed in data from profiles intersecting the Carpathians in the west at the contact with the Bohemian Massif; similar feature was also found in data at the northern edge of the Carpathians at the contact with the North European Platform. Modelling of these anomalous Pn phases shows that they originate due to local structural anomalies of the Moho discontinuity detected in several places along the Western Carpathian arc. Such anomalies are located in close lateral proximity of the Pieniny Klippen Belt representing the contact between the stable European Plate in the north and the ALCAPA (Alpine-Carpathian-Pannonian) microplate in the south. Thus, the complex local Moho topography modelled from the Pn phases suggests tectonic relation to the formation of the Carpathian orogen. The result is supported by correlation with the large-scale Carpathian conductivity anomaly modelled in the Carpathians at a mid-crustal level. Relative lateral position of these two structures together with the Pieniny Klippen Belt at the surface delineates a zone affected by deformations at various depths along the whole Western Carpathian arc.

Recursion equations in predicting band width under gradient elution.

PubMed

Liang, Heng; Liu, Ying

2004-06-18

The evolution of solute zone under gradient elution is a typical problem of non-linear continuity equation since the local diffusion coefficient and local migration velocity of the mass cells of solute zones are the functions of position and time due to space- and time-variable mobile phase composition. In this paper, based on the mesoscopic approaches (Lagrangian description, the continuity theory and the local equilibrium assumption), the evolution of solute zones in space- and time-dependent fields is described by the iterative addition of local probability density of the mass cells of solute zones. Furthermore, on macroscopic levels, the recursion equations have been proposed to simulate zone migration and spreading in reversed-phase high-performance liquid chromatography (RP-HPLC) through directly relating local retention factor and local diffusion coefficient to local mobile phase concentration. This new approach differs entirely from the traditional theories on plate concept with Eulerian description, since band width recursion equation is actually the accumulation of local diffusion coefficients of solute zones to discrete-time slices. Recursion equations and literature equations were used in dealing with same experimental data in RP-HPLC, and the comparison results show that the recursion equations can accurately predict band width under gradient elution.

Measurement of the CP-violating weak phase ϕs and the decay width difference ΔΓs using the Bs0 → J / ψ ϕ (1020) decay channel in pp collisions at √{ s} = 8 TeV

NASA Astrophysics Data System (ADS)

Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Knünz, V.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Cornelis, T.; de Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Ochesanu, S.; Rougny, R.; van de Klundert, M.; van Haevermaet, H.; van Mechelen, P.; van Remortel, N.; van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; de Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; van Doninck, W.; van Mulders, P.; van Onsem, G. P.; van Parijs, I.; Barria, P.; Brun, H.; Caillol, C.; Clerbaux, B.; de Lentdecker, G.; Delannoy, H.; Fasanella, G.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Maerschalk, T.; Marinov, A.; Perniè, L.; Randle-Conde, A.; Reis, T.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Yonamine, R.; Zenoni, F.; Zhang, F.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Dobur, D.; Fagot, A.; Garcia, G.; Gul, M.; McCartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva, S.; Sigamani, M.; Strobbe, N.; Tytgat, M.; van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; da Silveira, G. G.; Delaere, C.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Nuttens, C.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Hamer, M.; Hensel, C.; Mora Herrera, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; da Costa, E. M.; de Jesus Damiao, D.; de Oliveira Martins, C.; Fonseca de Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; de Souza Santos, A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Shaheen, S. M.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Zou, W.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Micanovic, S.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Bodlak, M.; Finger, M.; Finger, M.; El Sawy, M.; El-Khateeb, E.; Elkafrawy, T.; Mohamed, A.; Radi, A.; Salama, E.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Jarvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Dahms, T.; Davignon, O.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Lisniak, S.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Merlin, J. A.; Skovpen, K.; van Hove, P.; Gadrat, S.; Beauceron, S.; Bernet, C.; Boudoul, G.; Bouvier, E.; Carrillo Montoya, C. A.; Chierici, R.; Contardo, D.; Courbon, B.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Lagarde, F.; Laktineh, I. B.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Toriashvili, T.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Edelhoff, M.; Feld, L.; Heister, A.; Kiesel, M. K.; Klein, K.; Lipinski, M.; Ostapchuk, A.; Preuten, M.; Raupach, F.; Schael, S.; Schulte, J. F.; Verlage, T.; Weber, H.; Wittmer, B.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Endres, M.; Erdmann, M.; Erdweg, S.; Esch, T.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Klingebiel, D.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Olschewski, M.; Padeken, K.; Papacz, P.; Pook, T.; Radziej, M.; Reithler, H.; Rieger, M.; Scheuch, F.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Hoehle, F.; Kargoll, B.; Kress, T.; Kuessel, Y.; Künsken, A.; Lingemann, J.; Nehrkorn, A.; Nowack, A.; Nugent, I. M.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asin, I.; Bartosik, N.; Behnke, O.; Behrens, U.; Bell, A. J.; Borras, K.; Burgmeier, A.; Cakir, A.; Calligaris, L.; Campbell, A.; Choudhury, S.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Gallo, E.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Karacheban, O.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Korol, I.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Mankel, R.; Marfin, I.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Roland, B.; Sahin, M. Ö.; Saxena, P.; Schoerner-Sadenius, T.; Schröder, M.; Seitz, C.; Spannagel, S.; Trippkewitz, K. D.; Walsh, R.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Gonzalez, D.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Junkes, A.; Klanner, R.; Kogler, R.; Lapsien, T.; Lenz, T.; Marchesini, I.; Marconi, D.; Meyer, M.; Nowatschin, D.; Ott, J.; Pantaleo, F.; Peiffer, T.; Perieanu, A.; Pietsch, N.; Poehlsen, J.; Rathjens, D.; Sander, C.; Schettler, H.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Schwandt, J.; Seidel, M.; Sola, V.; Stadie, H.; Steinbrück, G.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Vormwald, B.; Akbiyik, M.; Barth, C.; Baus, C.; Berger, J.; Böser, C.; Butz, E.; Chwalek, T.; Colombo, F.; de Boer, W.; Descroix, A.; Dierlamm, A.; Fink, S.; Frensch, F.; Giffels, M.; Gilbert, A.; Hartmann, F.; Heindl, S. M.; Husemann, U.; Katkov, I.; Kornmayer, A.; Lobelle Pardo, P.; Maier, B.; Mildner, H.; Mozer, M. U.; Müller, T.; Müller, Th.; Plagge, M.; Quast, G.; Rabbertz, K.; Röcker, S.; Roscher, F.; Simonis, H. J.; Stober, F. M.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weber, M.; Weiler, T.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Psallidas, A.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Tziaferi, E.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Bencze, G.; Hajdu, C.; Hazi, A.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Molnar, J.; Szillasi, Z.; Bartók, M.; Makovec, A.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Mal, P.; Mandal, K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Gupta, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Mehta, A.; Mittal, M.; Singh, J. B.; Walia, G.; Kumar, Ashok; Bhardwaj, A.; Choudhary, B. C.; Garg, R. B.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Nishu, N.; Ranjan, K.; Sharma, R.; Sharma, V.; Banerjee, S.; Bhardwaj, R.; Bhattacharya, S.; Chatterjee, K.; Dey, S.; Dutta, S.; Jain, Sa.; Majumdar, N.; Modak, A.; Mondal, K.; Mukherjee, S.; Mukhopadhyay, S.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Abdulsalam, A.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Banerjee, S.; Bhowmik, S.; Chatterjee, R. M.; Dewanjee, R. K.; Dugad, S.; Ganguly, S.; Ghosh, S.; Guchait, M.; Gurtu, A.; Kole, G.; Kumar, S.; Mahakud, B.; Maity, M.; Majumder, G.; Mazumdar, K.; Mitra, S.; Mohanty, G. B.; Parida, B.; Sarkar, T.; Sudhakar, K.; Sur, N.; Sutar, B.; Wickramage, N.; Chauhan, S.; Dube, S.; Sharma, S.; Bakhshiansohi, H.; Behnamian, H.; Etesami, S. M.; Fahim, A.; Goldouzian, R.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Colaleo, A.; Creanza, D.; Cristella, L.; de Filippis, N.; de Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Battilana, C.; Benvenuti, A. C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Chhibra, S. S.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Travaglini, R.; Cappello, G.; Chiorboli, M.; Costa, S.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Gonzi, S.; Gori, V.; Lenzi, P.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Tropiano, A.; Viliani, L.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Primavera, F.; Calvelli, V.; Ferro, F.; Lo Vetere, M.; Monge, M. R.; Robutti, E.; Tosi, S.; Brianza, L.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Gerosa, R.; Ghezzi, A.; Govoni, P.; Malvezzi, S.; Manzoni, R. A.; Marzocchi, B.; Menasce, D.; Moroni, L.; Paganoni, M.; Pedrini, D.; Ragazzi, S.; Redaelli, N.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; di Guida, S.; Esposito, M.; Fabozzi, F.; Iorio, A. O. M.; Lanza, G.; Lista, L.; Meola, S.; Merola, M.; Paolucci, P.; Sciacca, C.; Thyssen, F.; Azzi, P.; Bacchetta, N.; Benato, L.; Bisello, D.; Boletti, A.; Carlin, R.; Checchia, P.; Dall'Osso, M.; Dorigo, T.; Gasparini, F.; Gasparini, U.; Gonella, F.; Gozzelino, A.; Kanishchev, K.; Lacaprara, S.; Margoni, M.; Maron, G.; Meneguzzo, A. T.; Michelotto, M.; Pazzini, J.; Pozzobon, N.; Ronchese, P.; Simonetto, F.; Torassa, E.; Tosi, M.; Zanetti, M.; Zotto, P.; Zucchetta, A.; Zumerle, G.; Braghieri, A.; Magnani, A.; Montagna, P.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Alunni Solestizi, L.; Biasini, M.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Mantovani, G.; Menichelli, M.; Saha, A.; Santocchia, A.; Spiezia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Broccolo, G.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fedi, G.; Foà, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Serban, A. T.; Spagnolo, P.; Squillacioti, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Barone, L.; Cavallari, F.; D'Imperio, G.; Del Re, D.; Diemoz, M.; Gelli, S.; Jorda, C.; Longo, E.; Margaroli, F.; Meridiani, P.; Organtini, G.; Paramatti, R.; Preiato, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Traczyk, P.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bellan, R.; Biino, C.; Cartiglia, N.; Costa, M.; Covarelli, R.; Degano, A.; Dellacasa, G.; Demaria, N.; Finco, L.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Monteil, E.; Musich, M.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. 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W.; Wyslouch, B.; Yang, M.; Zhukova, V.; Dahmes, B.; Finkel, A.; Gude, A.; Hansen, P.; Kalafut, S.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Keller, J.; Knowlton, D.; Kravchenko, I.; Lazo-Flores, J.; Meier, F.; Monroy, J.; Ratnikov, F.; Siado, J. E.; Snow, G. R.; Alyari, M.; Dolen, J.; George, J.; Godshalk, A.; Harrington, C.; Iashvili, I.; Kaisen, J.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira de Lima, R.; Trocino, D.; Wang, R.-J.; Wood, D.; Zhang, J.; Hahn, K. A.; Kubik, A.; Mucia, N.; Odell, N.; Pollack, B.; Pozdnyakov, A.; Schmitt, M.; Stoynev, S.; Sung, K.; Trovato, M.; Velasco, M.; Brinkerhoff, A.; Dev, N.; Hildreth, M.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Lynch, S.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Pearson, T.; Planer, M.; Reinsvold, A.; Ruchti, R.; Smith, G.; Taroni, S.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Hart, A.; Hill, C.; Hughes, R.; Ji, W.; Kotov, K.; Ling, T. Y.; Liu, B.; Luo, W.; Puigh, D.; Rodenburg, M.; Winer, B. L.; Wulsin, H. W.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Koay, S. A.; Lujan, P.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Palmer, C.; Piroué, P.; Quan, X.; Saka, H.; Stickland, D.; Tully, C.; Werner, J. S.; Zuranski, A.; Malik, S.; Barnes, V. E.; Benedetti, D.; Bortoletto, D.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, K.; Kress, M.; Miller, D. H.; Neumeister, N.; Radburn-Smith, B. C.; Shi, X.; Shipsey, I.; Silvers, D.; Sun, J.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Redjimi, R.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Harel, A.; Hindrichs, O.; Khukhunaishvili, A.; Petrillo, G.; Verzetti, M.; Demortier, L.; Arora, S.; Barker, A.; Chou, J. P.; Contreras-Campana, C.; Contreras-Campana, E.; Duggan, D.; Ferencek, D.; Gershtein, Y.; Gray, R.; Halkiadakis, E.; Hidas, D.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Lath, A.; Nash, K.; Panwalkar, S.; Park, M.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Foerster, M.; Riley, G.; Rose, K.; Spanier, S.; York, A.; Bouhali, O.; Castaneda Hernandez, A.; Dalchenko, M.; de Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Flanagan, W.; Gilmore, J.; Kamon, T.; Krutelyov, V.; Mueller, R.; Osipenkov, I.; Pakhotin, Y.; Patel, R.; Perloff, A.; Rose, A.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Undleeb, S.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Ni, H.; Sheldon, P.; Snook, B.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Boutle, S.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Wolfe, E.; Wood, J.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Christian, A.; Dasu, S.; Dodd, L.; Duric, S.; Friis, E.; Gomber, B.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ross, I.; Ruggles, T.; Sarangi, T.; Savin, A.; Sharma, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.

2016-06-01

The CP-violating weak phase ϕs of the Bs0 meson and the decay width difference ΔΓs of the Bs0 light and heavy mass eigenstates are measured with the CMS detector at the LHC using a data sample of Bs0 → J / ψ ϕ (1020) →μ+μ-K+K- decays. The analysed data set corresponds to an integrated luminosity of 19.7fb-1 collected in pp collisions at a centre-of-mass energy of 8TeV. A total of 49 200 reconstructed Bs0 decays are used to extract the values of ϕs and ΔΓs by performing a time-dependent and flavour-tagged angular analysis of the μ+μ-K+K- final state. The weak phase is measured to be ϕs = - 0.075 ± 0.097 (stat) ± 0.031 (syst) rad, and the decay width difference is ΔΓs = 0.095 ± 0.013 (stat) ± 0.007 (syst) ps-1.

Possible long-term decline in impact rates. 2. Lunar impact-melt data regarding impact history

NASA Astrophysics Data System (ADS)

Hartmann, William K.; Quantin, Cathy; Mangold, Nicolas

2007-01-01

Crater counts at lunar landing sites with measured ages establish a steep decline in cratering rate during the period ˜3.8 to ˜3.1 Gyr ago. Most models of the time dependence suggest a roughly constant impact rate (within factor ˜2) after about 3 Gyr ago, but are based on sparse data. Recent dating of impact melts from lunar meteorites, and Apollo glass spherules, clarifies impact rates from ˜3.2 to ˜2 Gyr ago or less. Taken together, these data suggest a decline with roughly 700 Myr half-life around 3 Gyr ago, and a slower decline after that, dropping by a factor ˜3 from about ˜2.3 Gyr ago until the present. Planetary cratering involved several phases with different time behaviors: (1) rapid sweep-up of most primordial planetesimals into planets in the first hundred Myr, (2) possible later effects of giant planet migration with enhanced cratering, (3) longer term sweep-up of leftover planetesimals, and finally (4) the present long-term "leakage" of asteroids from reservoirs such as the main asteroid belt and Kuiper belt. In addition, at any given point on the Moon, a pattern of "spikes" (sharp maxima of relatively narrow time width) will appear in the production rate of smaller craters (≲500 m?), not only from secondary debris from large primary lunar impacts at various distances from the point in question, but also from asteroid breakups dotted through Solar System history. The pattern of spikes varies according to type of sample being measured (i.e., glass spherules vs impact melts). For example, several data sets show an impact rate spike ˜470 Myr ago associated with the asteroid belt collision that produced the L chondrites (see Section 3.6 below). Such spikes should be less prominent in the production record of craters of D≳ few km. These phenomena affect estimates of planetary surfaces ages from crater counts, as discussed in a companion paper [Quantin, C., Mangold, N., Hartmann, W.K., Allemand, P., 2007. Icarus 186, 1-10]. Fewer impact melts and glass spherules are found at ˜3.8 Gyr than at ˜3.5 Gyr ago, even though the impact rate itself is known to have been higher at 3.8 Gyr ago than 3.5 Gyr. This disproves the assertion by Ryder [Ryder, G., 1990. EOS 71, 313, 322-323] and Cohen et al. [Cohen, B.A., Swindle, T.D., Kring, D.A., 2000. Science 290, 1754-1756] that ancient impact melts are a direct proxy for ancient impact (cf. Section 3.3). This result raises questions about how to interpret cratering history before 3.8 Gyr ago.

Virtual Reference, Real Money: Modeling Costs in Virtual Reference Services

ERIC Educational Resources Information Center

Eakin, Lori; Pomerantz, Jeffrey

2009-01-01

Libraries nationwide are in yet another phase of belt tightening. Without an understanding of the economic factors that influence library operations, however, controlling costs and performing cost-benefit analyses on services is difficult. This paper describes a project to develop a cost model for collaborative virtual reference services. This…

78 FR 57208 - Notice of Passenger Facility Charge (PFC) Approvals and Disapprovals

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-17

... LEVEL: End of runway deicing program--phase 1, runway 34R. Taxiway S pavement reconstruction. Replace carousel 9 and oversized bag belt TU3. Terminal redevelopment program--design and associated technical... APPROVED FOR COLLECTION AND USE: PFC program administration. Design taxiways A, L and B. BRIEF DESCRIPTION...

The Role of the Auroral Processes in the Formation of the Outer Electron Radiation Belt

NASA Astrophysics Data System (ADS)

Stepanova, M. V.; Antonova, E. E.; Pinto, V. A.; Moya, P. S.; Riazantseva, M.; Ovchinnikov, I.

2016-12-01

The role of the auroral processes in the formation of the outer electron radiation belt during storms is analyzed using the data of RBSP mission, low orbiting satellites and ground based observations. We analyze fluxes of the low energy precipitating ions using data of the Defense Meteorological Satellite Program (DMSP). The location of the auroral electrojet is obtained from the IMAGE magnetometer network, and of the electron distribution in the outer radiation belt from the RBSP mission. We take into account the latest results on the auroral oval mapping in accordance with which the most part of the auroral oval maps not to the plasma sheet. It maps into the surrounding the Earth plasma ring in which transverse currents are closed inside the magnetosphere. Such currents constitute the high latitude continuation of the ordinary ring current. The development of the ring current and its high latitude continuation generates strong distortion of the Earth's magnetic field and corresponding adiabatic variation of the relativistic electron fluxes. This adiabatic variation should be considered for the analysis of the processes of the acceleration of relativistic electrons and formation of the outer radiation belt. We also analyze the plasma pressure profiles during storms and demonstrate the formation of sharp plasma pressure peak at the equatorial boundary of the auroral oval. It is shown that the observed this peak is directly connected to the creation of the seed population of relativistic electrons. We discuss the possibility to predict the position of new radiation belt during recovery phase of the magnetic storm using data of low orbiting and ground based observations.

Auditory-nerve single-neuron thresholds to electrical stimulation from scala tympani electrodes.

PubMed

Parkins, C W; Colombo, J

1987-12-31

Single auditory-nerve neuron thresholds were studied in sensory-deafened squirrel monkeys to determine the effects of electrical stimulus shape and frequency on single-neuron thresholds. Frequency was separated into its components, pulse width and pulse rate, which were analyzed separately. Square and sinusoidal pulse shapes were compared. There were no or questionably significant threshold differences in charge per phase between sinusoidal and square pulses of the same pulse width. There was a small (less than 0.5 dB) but significant threshold advantage for 200 microseconds/phase pulses delivered at low pulse rates (156 pps) compared to higher pulse rates (625 pps and 2500 pps). Pulse width was demonstrated to be the prime determinant of single-neuron threshold, resulting in strength-duration curves similar to other mammalian myelinated neurons, but with longer chronaxies. The most efficient electrical stimulus pulse width to use for cochlear implant stimulation was determined to be 100 microseconds/phase. This pulse width delivers the lowest charge/phase at threshold. The single-neuron strength-duration curves were compared to strength-duration curves of a computer model based on the specific anatomy of auditory-nerve neurons. The membrane capacitance and resulting chronaxie of the model can be varied by altering the length of the unmyelinated termination of the neuron, representing the unmyelinated portion of the neuron between the habenula perforata and the hair cell. This unmyelinated segment of the auditory-nerve neuron may be subject to aminoglycoside damage. Simulating a 10 micron unmyelinated termination for this model neuron produces a strength-duration curve that closely fits the single-neuron data obtained from aminoglycoside deafened animals. Both the model and the single-neuron strength-duration curves differ significantly from behavioral threshold data obtained from monkeys and humans with cochlear implants. This discrepancy can best be explained by the involvement of higher level neurologic processes in the behavioral responses. These findings suggest that the basic principles of neural membrane function must be considered in developing or analyzing electrical stimulation strategies for cochlear prostheses if the appropriate stimulation of frequency specific populations of auditory-nerve neurons is the objective.

Atom Probe Tomography of Phase and Grain Boundaries in Experimentally-Deformed and Hot-Pressed Wehrlite

NASA Astrophysics Data System (ADS)

Cukjati, J.; Parman, S. W.; Cooper, R. F.; Zhao, N.

2017-12-01

Atom probe tomography (APT) was used to characterize the chemistry of three grain boundaries: an olivine-olivine (ol-ol) and olivine-clinopyroxene (ol-cpx) boundary in fine-grained experimentally-deformed wehrlite and an ol-cpx boundary in a fine-grained, hot-pressed wehrlite. Grain boundaries were extracted and formed into APT tips using a focused ion beam (FIB). The tips were analyzed in a reflectron-equipped LEAP4000HR (Harvard University) at 1% or 0.5% detection rate, 5pJ laser energy and 100kHz pulse rate. Total ion counts are between 40 and 100 million per tip. Examination of grain and phase boundaries in wehrlite are of interest since slow-diffusing and olivine-incompatible cations present in cpx (e.g. Ca and Al) may control diffusion-accommodated grain boundary sliding and affect mantle rheology (Sundberg & Cooper, 2008). At steady state, ol-cpx aggregates are weaker than either ol or cpx end member, the results of which are not currently well-explained. We investigate grain boundary widths to understand the transport of olivine-incompatible elements. Widths of grain/phase boundary chemical segregation are between 3nm and 6nm for deformed ol-ol and ol-cpx samples; minimally-deformed (hot-pressed) samples having slightly wider chemical segregation widths. Chemical segregation widths were determined from profiles of Na, Al, P, Cl, K, Ca, or Ni, although not all listed elements can be used for all samples (e.g. Na, K segregation profiles can only be observed for ol-ol sample). These estimates are consistent with prior estimates of grain boundary segregation by atom probe tomography on ol-ol and opx-opx samples (Bachhav et al., 2015) and are less than ol-ol interface widths analyzed by STEM/EDX (Hiraga, Anderson, & Kohlstedt, 2007). STEM/EDX will be performed on deformed wehrlite to investigate chemical profile as a function of applied stress orientation and at length scales between those observable by APT and EPMA. Determination of phase boundary chemistry and structure allows for better modeling of the rheology of multiphase aggregates and better understanding of diffusive transport and storage of incompatible elements along grain boundaries.

INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: Line width of a single longitudinal mode emitted by an AlGaAs heterojunction laser

NASA Astrophysics Data System (ADS)

Bogatov, Alexandr P.; Eliseev, P. G.; Luk'yanov, S. A.; Pak, G. T.; Petrakova, T. V.

1988-11-01

A nonmonotonic dependence of the emission line width on the power was observed for a single longitudinal mode of an AlGaAs heterojunction laser. This behavior could be due to the dependence of the waveguide coefficient of the amplitude-phase coupling on the nature of operation of the laser.

Modeling the temporal and spatial variations of the vertical structure of Jupiter's atmosphere using observations of the 3-0 hydrogen quadrupole lines

NASA Technical Reports Server (NTRS)

Cunningham, C. C.; Hunten, D. M.; Tomasko, M. G.

1986-01-01

An observational program was established in 1983 to monitor the spatial and temporal variations in the Jovian atmosphere over short and long time scales. The program involves tracking several different longitudes as they rotate around the planet from one limb to another. This tracking experiment was done at many different wavelengths including the 3-0 S(1) and S(0) hydrogen quadrupole lines as well as several broad band methane absorptions. The June 1983 hydrogen quadrupole data was reduced and equivalent widths were measured for approximately 25 east-west positions across the planet at 7 different latitudes for both wavelengths. The data for the South Tropical Zone (20 deg. S) was modeled extensively and the effects of the various model parameters on the value of the calculated equivalent widths of both lines was measured as a longitude rotated from the east (or morning) limb to the west (or evening) limb. The value of the equivalent width is also quite sensitive to the height of the NH3 cloud top and to the value used for the single scattering albedo. A combination of these parameters changing on a diurnal time scale could also explain these observations. This gradual increase from one limb to the other appears in the data for both the North and South Equatorial Belts as well as the equatorial region and the North Tropical Zone. Models that used only normal hydrogen and models that used only equilibrium hydrogen were studied.

Single-Mode WGM Resonators Fabricated by Diamond Turning

NASA Technical Reports Server (NTRS)

Grudinin, Ivan; Maleki, Lute; Savchenkov, Anatoliy; Matsko, Andrewy; Strekalov, Dmitry; Iltchenko, Vladimir

2008-01-01

A diamond turning process has made possible a significant advance in the art of whispering-gallery-mode (WGM) optical resonators. By use of this process, it is possible to fashion crystalline materials into WGM resonators that have ultrahigh resonance quality factors (high Q values), are compact (ranging in size from millimeters down to tens of microns), and support single electromagnetic modes. This development combines and extends the developments reported in "Few- Mode Whispering-Gallery-Mode Resonators" (NPO-41256), NASA Tech Briefs, Vol. 30, No. 1 (January 2006), page 16a and "Fabrication of Submillimeter Axisymmetric Optical Components" (NPO-42056), NASA Tech Briefs, Vol. 31, No. 5 (May 2007), page 10a. To recapitulate from the first cited prior article: A WGM resonator of this special type consists of a rod, made of a suitable transparent material, from which protrudes a thin circumferential belt of the same material. The belt is integral with the rest of the rod and acts as a circumferential waveguide. If the depth and width of the belt are made appropriately small, then the belt acts as though it were the core of a single-mode optical fiber: the belt and the rod material adjacent to it support a single, circumferentially propagating mode or family of modes. To recapitulate from the second cited prior article: A major step in the fabrication of a WGM resonator of this special type is diamond turning or computer numerically controlled machining of a rod of a suitable transparent crystalline material on an ultrahigh-precision lathe. During the rotation of a spindle in which the rod is mounted, a diamond tool is used to cut the rod. A computer program is used to control stepping motors that move the diamond tool, thereby controlling the shape cut by the tool. Because the shape can be controlled via software, it is possible to choose a shape designed to optimize a resonator spectrum, including, if desired, to limit the resonator to supporting a single mode. After diamond turning, a resonator can be polished to increase its Q. By virtue of its largely automated, computer-controlled nature, the process is suitable for mass production of nominally identical single-mode WGM resonators. In a demonstration of the capabilities afforded by this development, a number of WGM resonators of various designs were fabricated side by side on the surface of a single CaF2 rod (see figure).

Origin of the Uinta recess, Sevier fold thrust belt, Utah: influence of basin architecture on fold thrust belt geometry

NASA Astrophysics Data System (ADS)

Paulsen, Timothy; Marshak, Stephen

1999-11-01

Structural trends in the Sevier fold-thrust belt define a pronounced concave-to-the-foreland map-view curve, the Uinta recess, in north-central Utah. This recess separates two convex-to-the-foreland curves, the Provo salient on the south and the Wyoming salient on the north. The two limbs of the recess comprise transverse zones (fault zones at a high-angle to the regional trend of the orogen) that border the flanks of the east-west-trending Uinta/Cottonwood arch. Our structural analysis indicates that the transverse zones formed during the Sevier orogeny, and that they differ markedly from each other in structural style. The Charleston transverse zone (CTZ), on the south side of the arch, initiated as a complex sinistral strike-slip fault system that defines the abrupt northern boundary of the Provo salient. The Mount Raymond transverse zone (MRTZ), on the north side of the arch, represents the region in which the southeast-verging southern limb of the gently curving Wyoming salient was tilted northwards during the Laramide phase of uplift of the Uinta/Cottonwood arch. In effect, the MRTZ represents an oblique cross section through a thrust belt. The contrasting architecture of these transverse zones demonstrates how pre-deformation basin geometry influences the geometry of a fold-thrust belt. Analysis of isopach maps indicates that, at the time the Sevier fold-thrust belt formed, the area just north of the present site of the Uinta/Cottonwood arch was a basement high, with a gently dipping north flank, and a steeply dipping south flank. Thus, predeformational sediment thickened abruptly to the south of the high and thickened gradually to the north of the high. As illustrated by sandbox models, the distance that a fold-thrust belt propagates into the foreland depends on the thickness of the sedimentary layer being deformed, so the shape of the salient mimics the longitudinal cross-sectional shape of the sedimentary basin. Where basins taper gradually along strike, the thrust belt curves gently, but where basins taper abruptly along strike, the thrust belt curves so tightly that it disarticulates and becomes bounded laterally by a strike-slip accommodation zone. The geometry of the Uinta recess provides a field example of this concept. Differential movement of Sevier thrusts led to formation of gradually curving thrusts on the north side of the high, because of the gradual slope of the high's north flank, but led to the along-strike disarticulation of thrusts on the south side of the high, because of the steep slope of the high's south flank. In effect, therefore, thrust belt map-view geometry provides insight into predeformational basin geometry.

Making the cold Kuiper belt in a planetary instability migration model

NASA Astrophysics Data System (ADS)

Gomes, Rodney S.

2017-06-01

Numerical integrations of the equations of motion of Jupiter, Saturn, three ice cores and a disk of planetesimals are undertaken. Two of the ice planets stand for Uranus and Neptune and a third one is expected to be ejected from the solar system. The planets start in compact cold orbits and each one is in mean motion resonance with its neighbor(s). The disk of planetesimals is placed just outside the outermost planet and is extended to 45 au. Five hundred integrations are done for each of four masses assigned to the disk, which are 25, 30, 35 and 40 Earth masses. The integrations are extended to 100 My. After that, I choose the successful runs in which there are four planets left in closed orbits around the Sun and I separate the good runs among the successful ones, defined by semi-major axes ranges around and not too far from the real ones. Among these good runs, I further choose by visual inspection those that yield an orbital distribution of planetesimals at the Kuiper belt region that resembles the real cold Kuiper belt. I extend these runs to 1 Gy and, after that, to 4.5 Gy. These last integrations for 3.5 Gy are done after replacing the orbits of the planets in the end of the 1 Gy integrations by their current orbits, changing the semi-major axes of the planetesimals so as to keep the same mean motion ratio with Neptune and assigning null masses for the planetesimals. Orbital distributions of the cold Kuiper belt obtained in some of the runs at 4.5 Gy are quite similar to that of the real cold Kuiper belt. The mass in the Kuiper belt region can be dynamically eroded to up to 90% of the original mass. The main conclusion is that the cold Kuiper belt is compatible with a past planetary instability phase even though in some of these runs Neptune's semi-major axis and eccentricity attained values simultaneously larger than 20 au and 0.2 for over 1 My.

Bragg reflection band width and optical rotatory dispersion of cubic blue-phase liquid crystals

NASA Astrophysics Data System (ADS)

Yoshida, Hiroyuki; Anucha, Konkanok; Ogawa, Yasuhiro; Kawata, Yuto; Ozaki, Masanori; Fukuda, Jun-ichi; Kikuchi, Hirotsugu

2016-10-01

The Bragg reflection band width and optical rotatory dispersion of liquid crystalline cholesteric blue phases (BPs) I and II are compared by numerical simulations. Attention is paid to the wavelength regions for which the reflection bands with lowest photon energies appear, i.e., the [110 ] direction for BP I and the [100 ] direction for BP II. Finite difference time domain and 4 ×4 matrix calculations performed on the theoretical director tensor distribution of BPs with the same material parameters show that BP II, which has simple cubic symmetry, has a wider photonic band gap than BP I, which has body centered cubic symmetry, possibly due to the fact that the density of the double-twist cylinders in BP II are twice that in BP I. The theoretical results on the Bragg reflection band width are supported by reflectance measurements performed on BPs I and II for light incident along the [110 ] and [100 ] directions, respectively.

Effect of heat treatment on properties of HfO2 film deposited by ion-beam sputtering

NASA Astrophysics Data System (ADS)

Liu, Huasong; Jiang, Yugang; Wang, Lishuan; Li, Shida; Yang, Xiao; Jiang, Chenghui; Liu, Dandan; Ji, Yiqin; Zhang, Feng; Chen, Deying

2017-11-01

The effects of atmosphere heat treatment on optical, stress, and microstructure properties of an HfO2 film deposited by ion-beam sputtering were systematically researched. The relationships among annealing temperature and refractive index, extinction coefficient, physical thickness, forbidden-band width, tape trailer width, Urbach energy, crystal phase structure, and stress were assessed. The results showed that 400 °C is the transformation point, and the microstructure of the HfO2 film changed from an amorphous into mixed-phase structure. Multistage phonons appeared on the HfO2 film, and the trends of the refractive index, extinction coefficient, forbidden-band width change, and Urbach energy shifted from decrease to increase. With the elevation of the annealing temperature, the film thickness increased monotonously, the compressive stress gradually turned to tensile stress, and the transformation temperature point for the stress was between 200 °C and 300 °C. Therefore, the change in the stress is the primary cause for the shifts in thin-film thickness.

Paleocene coal deposits of the Wilcox Group, Northeast Texas

USGS Publications Warehouse

Hook, Robert W.; Warwick, Peter D.; SanFilipo, John R.; Nichols, Douglas J.; Swanson, Sharon M.; Warwick, Peter D.; Karlsen, Alexander K.; Merrill, Matthew D.; Valentine, Brett J.

2011-01-01

The surface exposure of the Paleocene Wilcox Group in northeast Texas varies in width from 9 to 27 mi along an arcuate outcrop that extends southwest approximately 156 mi from the Texas-Arkansas State line to 32° latitude. Parts of Bowie, Camp, Cass, Franklin, Henderson, Hopkins, Morris, Navarro, Rains, Titus, Van Zandt, and Wood Counties are included in this outcrop belt (Figure 1). This area forms the northwestern flank of the East Texas Basin (Figure 2), the axis of which separates northeast Texas from the Sabine uplift structural area. The Wilcox Group dips south and southeast at 2° or less toward the axis of the East Texas Basin, with the exception of local salt-dome structures and a transcurrent structural high that extends from Monticello to Martin Lake (Figure 1).

Nanobelt formation of magnesium hydroxide sulfate hydrate via a soft chemistry process.

PubMed

Zhou, Zhengzhi; Sun, Qunhui; Hu, Zeshan; Deng, Yulin

2006-07-13

The nanobelt formation of magnesium hydroxide sulfate hydrate (MHSH) via a soft chemistry approach using carbonate salt and magnesium sulfate as reactants was successfully demonstrated. X-ray diffraction (XRD), energy dispersion X-ray spectra (EDS), selected area electron diffraction (SAED), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis revealed that the MHSH nanobelts possessed a thin belt structure (approximately 50 nm in thickness) and a rectangular cross profile (approximately 200 nm in width). The MHSH nanobelts suffered decomposition under electron beam irradiation during TEM observation and formed MgO with the pristine nanobelt morphology preserved. The formation process of the MHSH nanobelts was studied by tracking the morphology of the MHSH nanobelts during the reaction. A possible chemical reaction mechanism is proposed.

Vision-based weld pool boundary extraction and width measurement during keyhole fiber laser welding

NASA Astrophysics Data System (ADS)

Luo, Masiyang; Shin, Yung C.

2015-01-01

In keyhole fiber laser welding processes, the weld pool behavior is essential to determining welding quality. To better observe and control the welding process, the accurate extraction of the weld pool boundary as well as the width is required. This work presents a weld pool edge detection technique based on an off axial green illumination laser and a coaxial image capturing system that consists of a CMOS camera and optic filters. According to the difference of image quality, a complete developed edge detection algorithm is proposed based on the local maximum gradient of greyness searching approach and linear interpolation. The extracted weld pool geometry and the width are validated by the actual welding width measurement and predictions by a numerical multi-phase model.

Mode-based microparticle conveyor belt in air-filled hollow-core photonic crystal fiber.

PubMed

Schmidt, Oliver A; Euser, Tijmen G; Russell, Philip St J

2013-12-02

We show how microparticles can be moved over long distances and precisely positioned in a low-loss air-filled hollow-core photonic crystal fiber using a coherent superposition of two co-propagating spatial modes, balanced by a backward-propagating fundamental mode. This creates a series of trapping positions spaced by half the beat-length between the forward-propagating modes (typically a fraction of a millimeter). The system allows a trapped microparticle to be moved along the fiber by continuously tuning the relative phase between the two forward-propagating modes. This mode-based optical conveyor belt combines long-range transport of microparticles with a positional accuracy of 1 µm. The technique also has potential uses in waveguide-based optofluidic systems.

Radiation Belt Transport Driven by Solar Wind Dynamic Pressure Fluctuations

NASA Astrophysics Data System (ADS)

Kress, B. T.; Hudson, M. K.; Ukhorskiy, A. Y.; Mueller, H.

2012-12-01

The creation of the Earth's outer zone radiation belts is attributed to earthward transport and adiabatic acceleration of electrons by drift-resonant interactions with electromagnetic fluctuations in the magnetosphere. Three types of radial transport driven by solar wind dynamic pressure fluctuations that have been identified are: (1) radial diffusion [Falthammer, 1965], (2) significant changes in the phase space density radial profile due to a single or few ULF drift-resonant interactions [Ukhorskiy et al., 2006; Degeling et al., 2008], and (3) shock associated injections of radiation belt electrons occurring in less than a drift period [Li et al., 1993]. A progress report will be given on work to fully characterize different forms of radial transport and their effect on the Earth's radiation belts. The work is being carried out by computing test-particle trajectories in electric and magnetic fields from a simple analytic ULF field model and from global MHD simulations of the magnetosphere. Degeling, A. W., L. G. Ozeke, R. Rankin, I. R. Mann, and K. Kabin (2008), Drift resonant generation of peaked relativistic electron distributions by Pc 5 ULF waves, textit{J. Geophys. Res., 113}, A02208, doi:10.1029/2007JA012411. Fälthammar, C.-G. (1965), Effects of Time-Dependent Electric Fields on Geomagnetically Trapped Radiation, J. Geophys. Res., 70(11), 2503-2516, doi:10.1029/JZ070i011p02503. Li, X., I. Roth, M. Temerin, J. R. Wygant, M. K. Hudson, and J. B. Blake (1993), Simulation of the prompt energization and transport of radiation belt particles during the March 24, 1991 SSC, textit{Geophys. Res. Lett., 20}(22), 2423-2426, doi:10.1029/93GL02701. Ukhorskiy, A. Y., B. J. Anderson, K. Takahashi, and N. A. Tsyganenko (2006), Impact of ULF oscillations in solar wind dynamic pressure on the outer radiation belt electrons, textit{Geophys. Res. Lett., 33}(6), L06111, doi:10.1029/2005GL024380.

Formation of an Archean tectonic mélange in the Schreiber-Hemlo greenstone belt, Superior Province, Canada: Implications for Archean subduction-accretion process

NASA Astrophysics Data System (ADS)

Polat, Ali; Kerrich, Robert

1999-10-01

The late Archean (circa 2750-2670 Ma) Schreiber-Hemlo greenstone belt, Superior Province, Canada, is composed of tectonically juxtaposed fragments of oceanic plateaus (circa 2750-2700 Ma), oceanic island arcs (circa 2720-2695 Ma), and siliciclastic trench turbidites (circa 2705-2697 Ma). Following juxtaposition, these lithotectonic assemblages were collectively intruded by synkinematic tonalite-trondhjemite-granodiorite (TTG) plutons (circa 2720-2690 Ma) and ultramafic to felsic dikes and sills (circa 2690-2680 Ma), with subduction zone geochemical signatures. Overprinting relations between different sequences of structures suggest that the belt underwent at least three phases of deformation. During D1 (circa 2695-2685 Ma), oceanic plateau basalts and associated komatiites, arc-derived trench turbidites, and oceanic island arc sequences were all tectonically juxtaposed as they were incorporated into an accretionary complex. Fragmentation of these sequences resulted in broken formations and a tectonic mélange in the Schreiber assemblage of the belt. D2 (circa 2685-2680 Ma) is consistent with an intra-arc, right-lateral transpressional deformation. Fragmentation and mixing of D2 synkinematic dikes and sills suggest that mélange formation continued during D2. The D1 to D2 transition is interpreted in terms of a trenchward migration of the magmatic arc axis due to continued accretion and underplating. The D2 intra-arc strike-slip faults may have provided conduits for uprising melts from the descending slab, and they may have induced decompressional partial melting in the subarc mantle wedge, to yield synkinematic ultramafic to felsic intrusions. A similar close relationship between orogen-parallel strike-slip faulting and magmatism has recently been recognized in several Phanerozoic transpressional orogenic belts, suggesting that as in Phanerozoic counterparts, orogen-parallel strike-slip faulting in the Schreiber-Hemlo greenstone belt played an important role in magma emplacement.

Characteristics of Pitch Angle Distributions of 100s Kev Electrons in the Slot Region and Inner Radiation Belt­­­­­­­­

NASA Astrophysics Data System (ADS)

Zhao, H.; Li, X.; Blake, J. B.; Fennell, J.; Claudepierre, S. G.; Baker, D. N.; Jaynes, A. N.; Malaspina, D.

2014-12-01

The pitch angle distribution (PAD) of energetic electrons in the slot region and inner radiation belt received little attention in the past decades due to the lack of quality measurements. Using the state-of-art pitch-angle-resolved data from the Magnetic Electron Ion Spectrometer (MagEIS) instrument onboard the Van Allen Probes, a detailed analysis of 100s keV electron PADs below L =4 is performed, in which the PADs is categorized into three types: normal (flux peaking at 90°), cap (exceedingly peaking narrowly around 90°) and 90°-minimum (lower flux at 90°) PADs. By examining the characteristics of the PADs of 460 keV electrons for over a year, we find that the 90°-minimum PADs are generally present in the inner belt (L<2), while normal PADs dominate at L~3.5-4. In the region between, 90°-minimum PADs dominate during injection times and normal PADs dominate during quiet times. Cap PADs appear mostly at the decay phase of storms in the slot region and are likely caused by the pitch angle scattering of hiss waves. Fitting the normal PADs into sinnα form, the parameter n is much higher below L=3 than that in the outer belt and relatively constant in the inner belt but changes significantly in the slot region (2

A comprehensive sediment dynamics study of a major mud belt system on the inner shelf along an energetic coast.

PubMed

Liu, James T; Hsu, Ray T; Yang, Rick J; Wang, Ya Ping; Wu, Hui; Du, Xiaoqin; Li, Anchun; Chien, Steven C; Lee, Jay; Yang, Shouye; Zhu, Jianrong; Su, Chih-Chieh; Chang, Yi; Huh, Chih-An

2018-03-09

Globally mud areas on continental shelves are conduits for the dispersal of fluvial-sourced sediment. We address fundamental issues in sediment dynamics focusing on how mud is retained on the seabed on shallow inner shelves and what are the sources of mud. Through a process-based comprehensive study that integrates dynamics, provenance, and sedimentology, here we show that the key mechanism to keep mud on the seabed is the water-column stratification that forms a dynamic barrier in the vertical that restricts the upward mixing of suspended sediment. We studied the 1000 km-long mud belt that extends from the mouth of the Changjiang (Yangtze) River along the coast of Zhejiang and Fujian Provinces of China and ends on the west coast of Taiwan. This mud belt system is dynamically attached to the fluvial sources, of which the Changjiang River is the primary source. Winter is the constructive phase when active deposition takes place of fine-grained sediment carried mainly by the Changjiang plume driven by Zhe-Min Coastal Currents southwestward along the coast.

Dynamics of the outer radiation belts in relation to polar substorms and hot plasma injections at geostationary altitude

NASA Technical Reports Server (NTRS)

Sauvaud, J. A.; Winckler, J. R.

1981-01-01

Geostationary satellite and ground measurements of dynamic variations of the outer radiation belts and their relations with the development of auroral structures during magnetospheric substorms are analyzed. A comparison of measurements of the H or X geomagnetic field components made by seven auroral stations with ATS-6 low-energy and high-energy particle measurements during the multiple-onset substorm of Aug. 16, 1974 is presented which demonstrates that while the decrease in energetic particle fluxed ends only at the time of a strong substorm onset, rapid motions of the outer radiation belts may occur during the flux decrease. All-sky photographs of auroral phenomena taken at Fort Yukon and College, Alaska are then compared with ATS-1 energetic particle flux measurements in order to demonstrate the relation between flux decreases and increases and distinct substorm phases. Results support the hypothesis of a magnetospheric substorm precursor which appears to be an instability growing at the inner boundary of the plasma layer and approaching the earth, and underline the importance of current and magnetic field variations in charged particle dynamics.

Near-earth injection of MeV electrons associated with intense dipolarization electric fields: Van Allen Probes observations

DOE PAGES

Dai, Lei; Wang, Chi; Duan, Suping; ...

2015-08-10

Substorms generally inject tens to hundreds of keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeVelectron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the premidnight sector at L ~ 5.5, Van Allen Probes (Radiation Belt Storm Probes)-A observed a large dipolarization electric field (50 mV/m) over ~40 s and a dispersionless injection of electrons up to ~3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarizationmore » front. Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by 1 order of magnitude in less than 3 h in the outer radiation belt (L > 4.8). Our observations provide evidence that deep injections can supply significant MeV electrons.« less

Pressure waves in the aorta during isolated abdominal belt loading: the magnitude, phasing, and attenuation.

PubMed

Arregui-Dalmases, C; Del Pozo, E; Stacey, S; Kindig, M; Lessley, D; Lopez-Valdes, F; Forman, J; Kent, R

2011-07-01

While rupture of the aorta is a leading cause of sudden death following motor vehicle crashes, the specific mechanism that causes this injury is not currently well understood. Aortic ruptures occurring in the field are likely due to a complex combination of contributing factors such as acceleration, compression of the chest, and increased pressure within the aorta. The objective of the current study was to investigate one of these factors in more detail than has been done previously; specifically, to investigate the in situ intra-aortic pressure generated during isolated belt loading to the abdomen. Ten juvenile swine were subjected to dynamic belt loads applied to the abdomen. Intraaortic pressure was measured at multiple locations to assess the magnitude and propagation of the resulting blood pressure wave. The greatest average peak pressure (113.6 +/- 43.5 kPa) was measured in the abdominal aorta. Pressures measured in the thoracic aorta and aortic arch were 70 per cent and 50 per cent, respectively, that measured in the abdominal aorta. No macroscopic aortic trauma was observed. To the authors' knowledge the present study is the first one to document the presence, propagation, and attenuation of a transient pressure wave in the aorta generated by abdominal belt loading. The superiorly moving wave is sufficient to generate hydrostatic and intimal shear stress in the aorta, possibly contributing to the hypothesized mechanisms of traumatic aortic rupture.

Transpression as the main deformational event in an Archaean greenstone belt, northeastern Minnesota

NASA Technical Reports Server (NTRS)

Hudleston, P. J.; Schultz-Ela, D.; Bauer, R. L.; Southwick, D. L.

1986-01-01

Deformed and metamorphosed sedimentary and volcanic rocks of the Vermilion district constitute an Archean greenstone belt trending east-west between higher grade rocks of the Vermilion Granitic Complex to the north and the Giants Range batholith to the south. Metamorphic grade is low throughout, being lowest in the center of the belt (chlorite zone of the greenschist facies). All the measured strain, a cleavage or schistosity, and a mineral lineation in this belt are attributed to the main phase of deformation D sub 2 that followed an earlier nappe-forming event D sub 1, which left little evidence of penetrative fabric. Previous work assumed that the D sub 2 deformation resulted from north-south compression across the district. It is now believed that a significant component of this deformation resulted from dextral shear across the whole region. Thus the Vermilion fault, a late-state largely strike-slip structure that bounds the Vermilion district to the north, may simply be the latest, most brittle expression of a shear regime that was much more widespread in space and time. Features that are indicative of shear include ductile shear zones with sigmoidal foliation patterns, highly schistose zones with the development of shear bands, feldspar clasts or pyrite cubes with asymmetric pressure shadows, and the fact that the asymmetry of the F sub 2 folds is predominantly Z for at least 15 km south of the Vermilion fault.

Optical radar-based device for measuring automobile belt displacement in real time

NASA Astrophysics Data System (ADS)

Brennan, Brian W.; Gentile, John R.

1999-02-01

Ford Motor Company had a requirement to measure fan belt vibration on their 4.6 liter Cobra-Mustang engine. While this sensor was to be used in the laboratory, it would also be used for field testing of this engine. The general operation temperature was -40 to 120 degrees C, but there was an engine 'soak-back' requirement of up to 200 degrees C. The vibration requirement was 3g continuous at 10 Hz with 20g shock. Humidity was 0-95 percent. Without active cooling, the temperature environment eliminated engine mounted electronics and with it some more common approaches such as laser triangulation based sensing. A laser radar concept was developed which features remotely located electronics, fiber optic delivery and return of the signal and an engine mounted optic head. The three lens design of the receive optics is a compromise choice designed to maximize power at the receiver over the full travel of the belt. The electronic scheme consists of a time-to-amplitude converter based on a precise time interval derived from the phase difference of logic level pulse trains which in turn are formed by the 'exclusive O Ring' of the transmit and receive pulses. In practice, a 10 MHz pulse train is transmitted to the vibrating belt which coupled with some fast electronics results in about 1 0.1 mm resolution, sufficient for this application.

Carboniferous Proto-type Basin Evolution of Junggar Basin in Northwest China: Implications for the Growth Models of Central Asia Orogenic Belt

NASA Astrophysics Data System (ADS)

He, D.

2016-12-01

The Junggar Basin locates in the central part of Paleo-Asian Ocean tectonic domain, and records the dynamic processes of the Central Asian Orogenic Belt from subduction-accretion-collision to later intracontinental deformations. Carboniferous is the key period from subduction to closure in the tectonic evolution of Paleo-Asian Ocean. Based on the borehole, outcrop, seismic and gravity and magnetic anomaly data, the paper made analysis of the Carboniferous basin evolution.Geo-chronological results for the borehole volcanic rocks suggest that the Junggar Basin and adjacent area had five periods of volcanic activities, including two periods in the Early Carboniferous (359-347Ma 347-331Ma and 331-324Ma) and three periods in the Late Carboniferous (323-307Ma and 307-300Ma). Regional unconformities divided the Carboniferous into two tectono-stratigraphic sequences: Lower Carboniferous and Upper Carboniferous. The former is characterized by compressional structures and involves massive calc-alkaline basalts, andesites, dacites and rhyolites, whereas the later is mainly controlled by extensional faults and dominated by intermediate-mafic volcanic rocks, with bimodal volcanic rocks in parts. The paper determined four Carboniferous arc-basin belts in the Junggar Basin and adjacent area from north to south: the Saur-Fuhai-Dulate, Heshituoluogai-Wulungu-Yemaquan, Darbut-Luliang-Karamaili, and Zhongguai-Mosuowan-Baijiahai-Qitai, and identified multi-type basins, such as fore-arc basin, retro-arc basin, intra-arc rift basin, foreland basin and passive continental margin basin,etc.. The Carboniferous proto-type basin evolution of the Junggar Basin can be divided into three phases such as, the early to middle Early Carboniferous subduction-related compressional phase, the late Early Carboniferous to middle Late Carboniferous subduction-related extensional phase and the late Late Carboniferous intra-continental fault-sag phase. The study discloses that the Junggar Basin is likely underlain by juvenile continental crust rather than unified Precambrian basement, and also implies that the Junggar Basin and adjacent area, even the entire CAOB, were built by successively northward amalgamation of multiple linear arc-basin systems characterized by southward accretion.

Energy dependence of relativistic electron variations in the outer radiation belt during the recovery phase of magnetic storms: Arase/XEP observations

NASA Astrophysics Data System (ADS)

Higashio, N.; Takashima, T.; Seki, K.; Yoshizumi, M.; Teramoto, M.; Hori, T.; Kurita, S.; Matsuoka, A.

2017-12-01

The Arase satellite was launched in December 2016. The extremely high-energy electron experiments(XEP) onboard Arase measures electrons in the energy range of 400 keV - 20 MeV. After the launch, the XEP has observed variations of the relativistic electrons successfully in the inner magnetosphere. There are roughly two candidate processes of electron acceleration. The first one is the adiabatic acceleration due to the radial transport of electrons from the plasma sheet to the inner magnetosphere. Interaction with ultra-low frequency (ULF) waves are a plausible candidate to drive the radial transport. Another acceleration process is the non-adiabatic acceleration of sub-relativistic electrons to the relativistic energies in the heart of the radiation belt. The interaction with very-low frequency (VLF) waves is considered to play an important role in the internal acceleration. One of the science goals of the XEP instrument is to understand the acceleration mechanisms of the relativistic electrons. In order to investigate the electron acceleration processes, we here focus on three geomagnetic storms occurred on March 27, April 4, and May 28, 2017, respectively. In these events, relativistic electrons in the outer belt showed a typical time variation, i.e., decrease in the main phase and then increase in the recovery phase. On one hand, the increase rates of the electrons are different between the storms. The March 27 storm, which is caused by the arrival of the high-speed coronal hole stream, accompanies a large increase of the relativistic electrons. The April 4 storm, which has a rapid Dst development and recovery, shows less acceleration and does not recover to the pre-storm level. The May 28 storm is caused by a CME and with moderate increase of the relativistic electrons especially in the small L region (L=[3,4]) . We will report on energy dependence of the increase rate and location of the relativistic electrons during the recovery phase, and their comparison between the three geomagnetic storms.

A quantitative analysis of transtensional margin width

NASA Astrophysics Data System (ADS)

Jeanniot, Ludovic; Buiter, Susanne J. H.

2018-06-01

Continental rifted margins show variations between a few hundred to almost a thousand kilometres in their conjugated widths from the relatively undisturbed continent to the oceanic crust. Analogue and numerical modelling results suggest that the conjugated width of rifted margins may have a relationship to their obliquity of divergence, with narrower margins occurring for higher obliquity. We here test this prediction by analysing the obliquity and rift width for 26 segments of transtensional conjugate rifted margins in the Atlantic and Indian Oceans. We use the plate reconstruction software GPlates (http://www.gplates.org) for different plate rotation models to estimate the direction and magnitude of rifting from the initial phases of continental rifting until breakup. Our rift width corresponds to the distance between the onshore maximum topography and the last identified continental crust. We find a weak positive correlation between the obliquity of rifting and rift width. Highly oblique margins are narrower than orthogonal margins, as expected from analogue and numerical models. We find no relationships between rift obliquities and rift duration nor the presence or absence of Large Igneous Provinces (LIPs).

Value Transmissions between Parents and Children: Gender and Developmental Phase as Transmission Belts

ERIC Educational Resources Information Center

Roest, Annette M. C.; Dubas, Judith Semon; Gerris, Jan R. M.

2010-01-01

This study applied the gender role model of socialization theory, the developmental aging theory, and the topic salience perspective to the investigation of parent-child value transmissions. Specifically, we examined whether the bi-directionality and selectivity of value transmissions differed as a function of parents' and children's gender and…

A dynamic model of the radiation-belt electron phase-space density based on POLAR/HIST measurements

NASA Astrophysics Data System (ADS)

Vassiliadis, D.; Green, J. C.

2007-12-01

The response of the energetic-electron phase-space density (PSD) in the radiation belts is subject to a delicate combination of acceleration and loss processes which are strongly determined by the magnetospheric configuration and field disturbance level. We quantify the response of the density to stormtime fields as observed by the HIST detector on board POLAR. Several distinct modes are identified, characterized by peak second- and third- adiabatic invariants and peak delay time. The modes represent quasiadiabatic transport due to ring current activity; high L* (~6), day-long acceleration linked to ULF wave-particle interaction; and low-L* (~3), minute- to hour-long acceleration interpreted to be due to transient inductive fields or VLF wave-particle interaction. The net transport due to these responses is not always or everywhere diffusive, therefore we quantify the degree of departure from diffusive transport for specific storm intervals and radial ranges. Taken together the response modes comprise a dynamic, nonlinear model which allows us to better understand the historic variability of the high-energy tail of the electron distribution in the inner magnetosphere.

Balance of baryon number in the quark coalescence model

NASA Astrophysics Data System (ADS)

Bialas, A.; Rafelski, J.

2006-02-01

The charge and baryon balance functions are studied in the coalescence hadronization mechanism of quark-gluon plasma. Assuming that in the plasma phase the qqbar pairs form uncorrelated clusters whose decay is also uncorrelated, one can understand the observed small width of the charge balance function in the Gaussian approximation. The coalescence model predicts even smaller width of the baryon-antibaryon balance function: σBBbar /σ+ - =√{ 2 / 3 }.

Superluminal tunneling of a relativistic half-integer spin particle through a potential barrier

NASA Astrophysics Data System (ADS)

Nanni, Luca

2017-11-01

This paper investigates the problem of a relativistic Dirac half-integer spin free particle tunneling through a rectangular quantum-mechanical barrier. If the energy difference between the barrier and the particle is positive, and the barrier width is large enough, there is proof that the tunneling may be superluminal. For first spinor components of particle and antiparticle states, the tunneling is always superluminal regardless the barrier width. Conversely, the second spinor components of particle and antiparticle states may be either subluminal or superluminal depending on the barrier width. These results derive from studying the tunneling time in terms of phase time. For the first spinor components of particle and antiparticle states, it is always negative while for the second spinor components of particle and antiparticle states, it is always positive, whatever the height and width of the barrier. In total, the tunneling time always remains positive for particle states while it becomes negative for antiparticle ones. Furthermore, the phase time tends to zero, increasing the potential barrier both for particle and antiparticle states. This agrees with the interpretation of quantum tunneling that the Heisenberg uncertainty principle provides. This study's results are innovative with respect to those available in the literature. Moreover, they show that the superluminal behaviour of particles occurs in those processes with high-energy confinement.

Systematic Onset of Periodic Patterns in Random Disk Packings

NASA Astrophysics Data System (ADS)

Topic, Nikola; Pöschel, Thorsten; Gallas, Jason A. C.

2018-04-01

We report evidence of a surprising systematic onset of periodic patterns in very tall piles of disks deposited randomly between rigid walls. Independently of the pile width, periodic structures are always observed in monodisperse deposits containing up to 1 07 disks. The probability density function of the lengths of disordered transient phases that precede the onset of periodicity displays an approximately exponential tail. These disordered transients may become very large when the channel width grows without bound. For narrow channels, the probability density of finding periodic patterns of a given period displays a series of discrete peaks, which, however, are washed out completely when the channel width grows.

Geologic Setting of the Hamme Tungsten District, North Carolina and Virginia

USGS Publications Warehouse

Parker, John Mason

1963-01-01

The Hamme tungsten district is in the eastern part of the Piedmont province, mainly in Vance County, North Carolina, but it extends a few miles into Virginia. The district is underlain by a central lenticular pluton of albite granodiorite that trends north-northeastward and is flanked on both sides by metamorphic rocks of low and medium grade that dip steeply westward. The relative ages of the metamorphic rocks are uncertain. The oldest rocks are likely to be the biotite gneisses in the eastern part of the district; successively younger units expose westward across the district are sericite-chlorite phyllites, greenstone, metafelsites, and metabasalts. The biotite gneisses and minor intercalated hornblende gneiss, which have a total thickness of many thousand feet, were derived from sediments. Some of the gneiss grades into phyllites and as probably formed by metasomatic alteration of the phyllites. Sericite-chlorite phyllite, epidote-quartz meta siltstone, quartzite, and conglomeratic phyllite occur principally in a wide belt on the west side of the central albite granodiorite. This unit is some 10,000 feet thick and originally consisted mainly of sediments of the graywacke suite. Greenstone totaling about 500 feet in thickness lies west of the phyllite and was derived from maflc lava flows and andesitic tuff. Metamorphosed massive aphanitic and porphyritic flows and dikes that range in composition from dacite to rhyolite, and phyllitic metatuffs and tuffaceous breccia are exposed west of the greenstone. These total at least 3,000 feet in thickness. Massive metabasalt that resembles greenstone but is less altered is common in the area between the Hamme district and the Virgilina district to the west. The thickness of the metabasalt is about 600 to 6,000 feet. The metamorphic rocks of the Hamme and Virgilina districts are parts of the Carolina slate belt, but map units cannot be directly correlated. Rocks in the Hamme district are thought by the writer to have been derived mainly from graywackes and volcanic flows, and subordinately from pyroclastic materials, whereas the rocks of the Virgilina district were interpreted by earlier workers as being mainly volcanic with much pyroclastic material but little sediment. Igneous, and perhaps pseudo igneous, rocks in the district include hornblende gabbro, albite granodiorite, aplite, and pegmatite--all of which are probably middle Paleozoic in age--and diabase and hypersthene tonalite of Late Triassic age. The gabbro forms three lenticular to subcircular bodies up to 2% miles in width in the western part of the area. Albite granodiorite forms a pluton with a maximum width of 7 miles which occupies the center of the area. At its northeastern end the pluton narrows abruptly to a point. Phyllite forms the wall rocks on all sides of the albite granodiorite. The contact is gradational and conformable in most places, but on the northwest side it cuts across wall structure for about 3 miles. Near its western edge the albite granodiorite includes a northeast-trending zone of schistose wall rock in and near which are localized the tungsten deposits. The origin of the albite granodiorite is uncertain, but it may have formed by the metasomatic replacement of the wallrocks, during which albite porphyroblasts developed first and were followed by microcline and quartz. Diabase and hypersthene tonalite occur as dikes and sills along four northward-trending belts. The dikes are a few feet to more than 300 feet thick, and several extend along strike for more than 10 miles. The Hamme district Is in the eastern part of the Carolina slate belt, and the Virg1l1na district lies along the western side of the belt. Rocks in the Hamme district dip mostly westward and in the Vifg1lina district dip mainly eastward into a syncline. This syncline, here named the Spewmarrow syncline, may be a structure of regional significance. Tungsten in the Hamme district occurs mainly

Tectonic evolution of the Satpura Mountain Belt: A critical evaluation and implication on supercontinent assembly

NASA Astrophysics Data System (ADS)

Mohanty, S.

2010-11-01

The Satpura Mountain Belt (also referred as Central Indian Tectonic Zone in recent literature) forms an important morphotectonic unit in the central part of India. Some of the recent workers have reported an orogenic event at ˜1000-900 Ma (termed "Sausar orogeny") which led to amalgamation of the North Indian Block and the South Indian Block and formation of the Satpura Mountain Belt. In this model the stratigraphic relations of two important lithostratigraphic units on either side of the Satpura Mountain Belt (the Sausar Group in the south and the Vindhyan Supergroup on the north) are suggested to be revised from previously held ideas. Critical analyses of available published work in the region to assess the status of the Sausar Group vis a vis the Vindhyan Supergroup was carried out. It is found that the ideas proposed by the recent workers stem from an earlier interpretation that the Sausar Group has monocyclic evolution and the earliest fabric in the Sausar Group is marked by a schistosity with EW strike. Re-mapping of the gneissic rocks and adjacent matasedimentary rocks of Khawasa, Deolapar, and Kandri-Mansar areas revealed presence of gneissic rocks and granulites of two generations, and of four phases of superposed deformations in the metasediments and gneisses. The older gneisses and granulites constitute the basement over which the rocks of the Sausar Group were deposited; and the younger gneisses developed by metamorphism and migmatisation of the rocks of the Sausar Group. The latter types are found in the Khawasa-Ramakona areas. Contrary to the belief of the recent workers that no volcanic activity is present in the Sausar Group, volcanic rocks marked by amygdular basic flows and tuffs have been mapped from different parts of the Sausar Group. Migmatisation and metamorphism of these volcanic rocks (of the Sausar Group) have given rise to amphibolites and granulites in Khawasa and Ramakona areas. Therefore, the use of fabric patterns in these areas to suggest that the granulite facies metamorphism in the Ramakona-Katangi granulite domain was pre-Sausar in age is debatable. Available geochronological data of the Satpura Mountain Belt and its eastward continuation into the Chhotanagpur Gneiss terrain indicate that the basement and cover rocks of these areas were subjected to multiple deformation and metamorphic episodes of similar style and nature. The earliest deformation and metamorphism of the rocks of the Sausar Group and its equivalent rocks to the east took place at ˜2100-1900 Ma. The regional EW trend of the belt developed during the second deformation at ˜1800-1700 Ma and again at ˜1600-1500 Ma. This deformation was accompanied by migmatisation and granulite facies metamorphism in the northern domain of the Sausar Belt and in the Chhotanagpur Gneiss region. Late phase low intensity deformations in the region were associated with thermal events at ˜1100-1000 Ma and ˜900-800 Ma. The ˜EW trending fabric, referred as "Satpura orogenic trend" in Indian literature marks a major compressional tectonic event, developed during the second deformation of the Sausar Group. This has its counter part in Western Australia as the Capricorn orogeny (˜1780-1830 Ma). The development of the Satpura Mountain Belt during the Grenvillian orogeny is ruled out from the synthesis of event stratigraphic data of the region and from its comparison with the Western Australian Craton.

Measurement of the CP-violating weak phase $$\\mathrm{ \\phi_s }$$ and the decay width difference $$ \\Delta \\Gamma_{ \\mathrm{s} }$$ using the $$ \\mathrm{B^0_s} \\to \\mathrm{J} / \\psi \\phi(1020) $$ decay channel in pp collisions at $$\\sqrt{s} =$$ 8 TeV

DOE PAGES

Khachatryan, Vardan

2016-03-23

The CP-violating weak phase φ s of the B 0 s meson and the decay width difference ΔΓs of the B 0 s light and heavy mass eigenstates are measured with the CMS detector at the LHC using a data sample of B 0 s →J/ψ φ(1020) → µ +µ -K +K - decays. Our analysed data set corresponds to an integrated luminosity of 19.7 fb -1 collected in pp collisions at a centre-of-mass energy of 8 TeV. Additionally, a total of 49 200 reconstructed B 0 s decays are used to extract the values of φs and ΔΓ smore » by performing a time-dependent and flavourtagged angular analysis of the µ +µ -K +K - final state. The weak phase is measured to be φ s = -0.075 ± 0.097 (stat) ± 0.031 (syst) rad, and the decay width difference is ΔΓ s = 0.095 ± 0.013 (stat) ± 0.007 (syst) ps -1 .« less

Measurement of the CP-violating weak phase $$\\mathrm{ \\phi_s }$$ and the decay width difference $$ \\Delta \\Gamma_{ \\mathrm{s} }$$ using the $$ \\mathrm{B^0_s} \\to \\mathrm{J} / \\psi \\phi(1020) $$ decay channel in pp collisions at $$\\sqrt{s} =$$ 8 TeV

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

Khachatryan, Vardan

The CP-violating weak phase φ s of the B 0 s meson and the decay width difference ΔΓs of the B 0 s light and heavy mass eigenstates are measured with the CMS detector at the LHC using a data sample of B 0 s →J/ψ φ(1020) → µ +µ -K +K - decays. Our analysed data set corresponds to an integrated luminosity of 19.7 fb -1 collected in pp collisions at a centre-of-mass energy of 8 TeV. Additionally, a total of 49 200 reconstructed B 0 s decays are used to extract the values of φs and ΔΓ smore » by performing a time-dependent and flavourtagged angular analysis of the µ +µ -K +K - final state. The weak phase is measured to be φ s = -0.075 ± 0.097 (stat) ± 0.031 (syst) rad, and the decay width difference is ΔΓ s = 0.095 ± 0.013 (stat) ± 0.007 (syst) ps -1 .« less

Study the Precipitation of Radiation Belt Electrons during the Rapid Dropout Events

NASA Astrophysics Data System (ADS)

Tu, W.; Cunningham, G.; Li, X.; Chen, Y.

2015-12-01

During the main phase of storms, the relativistic electron flux in the radiation belt can drop by orders of magnitude on timescales of a few hours. Where do the electrons go? This is one of the most important outstanding questions in radiation belt studies. Radiation belt electrons can be lost either by transport across the magnetopause into interplanetary space or by precipitation into the atmosphere. In this work we first conduct a survey of the MeV electron dropouts using the Van Allen Probes data in conjunction with the low-altitude measurements of precipitating electrons by 6 NOAA/POES satellites. The dropout events are categorized into three types: precipitation-loss dominant, outward radial diffusion dominant, or with contributions from both mechanisms. The survey results suggest the relative importance of precipitation and outward radial diffusion to the fast dropouts of radiation belt electrons, and their extent in L-shell and electron energy. Then, for specific events identified as dominated by precipitation loss, we use the Drift-Diffusion model, which includes the effects of azimuthal drift and pitch angle diffusion, to simulate both the electron dropout observed by Van Allen Probes and the distributions of drift-loss-cone electrons observed by multiple low-earth-orbit satellites (6 POES and the Colorado Student Space Weather Experiment). The model quantifies the electron precipitation loss and pitch angle diffusion coefficient, Dxx, with high temporal and spatial resolution. Finally, by comparing the Dxx derived from the model with those estimated from the quasi-linear theory using wave data from Van Allen Probes and other event-specific wave models, we are able to test the validity of quasi-linear theory and seek direct evidence of the wave-particle interactions during the dropouts.

Permian paleomagnetism of the Tien Shan fold belt, Central Asia: post-collisional rotations and deformation

NASA Astrophysics Data System (ADS)

Bazhenov, Mikhail L.; S. Burtman, Valentin; Dvorova, Ariadna V.

1999-11-01

Permian volcanic and sedimentary rocks were sampled from eight localities in the western and central parts of the Tien Shan fold belt. High-temperature, sometimes intermediate-temperature components isolated from these rocks at seven localities after stepwise thermal demagnetization are shown either to predate folding or be acquired during deformation; the conglomerate test at some localities is positive. The observed inclinations fit rather well with the Eurasian reference data, whereas the declinations are strongly deflected westward; westerly declinations have already been observed from the other parts of the Tien Shan (from the Turan plate in the west to the northern rim of Tarim and the Urumque area in the east). Our analysis shows that a considerable counterclockwise rotation of the Tien Shan fold belt as a rigid body is geologically improbable. We hypothesize that a sinistral shear zone existed over the fold belt thus accounting for systematically westerly declinations. This zone is about 300 km wide and is traced along the Tien Shan fold belt for 2500 km. A large area of Permian alkali magmatism in the West and Central Tien Shan is interpreted as an extensional domain conjugated with the shear zone. This shear zone can be accounted for by translation of the Kara Kum and Tarim blocks along the Eurasian boundary after their oblique collision in the Late Carboniferous. Two phases of rotation are recognized in the Tien Shan. The earlier rotation took place under shear strain during the D3 stage of deformation in the Artinskian-Ufimian. The later rotation is connected with transpression (D4 stage of deformation) and could occur from the Late Permian to Early Jurassic.

Turbulent transport of He II in active and passive phase separators using slit devices and porous media

NASA Technical Reports Server (NTRS)

Yuan, S. W. K.; Lee, J. M.; Frederking, T. H. K.

1988-01-01

The turbulent transport mode of vapor liquid phase separators (VLPS) for He II has been investigated comparing passive porous plug separators with active phase separators (APS) using slits of variable flow paths within a common frame of reference. It is concluded that the basic transport regimes in both devices are identical. An integrated Gorter-Mellink (1949) equation, found previously to predict VLPS results of porous plugs, is employed to analyze APS data published in the literature. It is found that the Gorter-Mellink flow rate parameter for 9-micron and 14-micron APS slit widths are relatively independent of the slit width, having a rate constant of about 9 + or - 10 percent. This agrees with the early heat flow results for He II entropy transport at zero net mass flow in wide capillaries and slits.

SAS-2 gamma-ray observations of PSR 1747-46. [radio pulsar

NASA Technical Reports Server (NTRS)

Thompson, D. J.; Fichtel, C. E.; Kniffen, D. A.; Ogelman, H. B.; Lamb, R. C.

1976-01-01

Evidence is reported for the observation of gamma-ray emission from the radio pulsar PSR 1747-46 by the gamma-ray telescope aboard SAS 2. The evidence is based on the presence of both an approximately 3-sigma enhancement of gamma rays at the pulsar's location and an approximately 4-sigma peak in the phase plot of 79 gamma-ray events whose phase was calculated from the pulsar's known period. The gamma-ray pulsation is found to appear at a phase lag of about 0.16 from that predicted by the radio observations. The pulsed gamma-ray fluxes above 35 MeV and 100 MeV are estimated, and it is shown that the gamma-ray pulse width is similar to the radio pulse width. It is concluded that PSR 1747-46 is a most likely candidate for pulsed gamma-ray emission.

Low-Temperature Crystal Structures of the Hard Core Square Shoulder Model.

PubMed

Gabriëlse, Alexander; Löwen, Hartmut; Smallenburg, Frank

2017-11-07

In many cases, the stability of complex structures in colloidal systems is enhanced by a competition between different length scales. Inspired by recent experiments on nanoparticles coated with polymers, we use Monte Carlo simulations to explore the types of crystal structures that can form in a simple hard-core square shoulder model that explicitly incorporates two favored distances between the particles. To this end, we combine Monte Carlo-based crystal structure finding algorithms with free energies obtained using a mean-field cell theory approach, and draw phase diagrams for two different values of the square shoulder width as a function of the density and temperature. Moreover, we map out the zero-temperature phase diagram for a broad range of shoulder widths. Our results show the stability of a rich variety of crystal phases, such as body-centered orthogonal (BCO) lattices not previously considered for the square shoulder model.

Quantification of the precipitation loss of radiation belt electrons observed by SAMPEX

NASA Astrophysics Data System (ADS)

Tu, Weichao; Selesnick, Richard; Li, Xinlin; Looper, Mark

2010-07-01

Based on SAMPEX/PET observations, the rates and the spatial and temporal variations of electron loss to the atmosphere in the Earth's radiation belt were quantified using a drift diffusion model that includes the effects of azimuthal drift and pitch angle diffusion. The measured electrons by SAMPEX can be distinguished as trapped, quasi-trapped (in the drift loss cone), and precipitating (in the bounce loss cone). The drift diffusion model simulates the low-altitude electron distribution from SAMPEX. After fitting the model results to the data, the magnitudes and variations of the electron lifetime can be quantitatively determined based on the optimum model parameter values. Three magnetic storms of different magnitudes were selected to estimate the various loss rates of ˜0.5-3 MeV electrons during different phases of the storms and at L shells ranging from L = 3.5 to L = 6.5 (L represents the radial distance in the equatorial plane under a dipole field approximation). The storms represent a small storm, a moderate storm from the current solar minimum, and an intense storm right after the previous solar maximum. Model results for the three individual events showed that fast precipitation losses of relativistic electrons, as short as hours, persistently occurred in the storm main phases and with more efficient loss at higher energies over wide range of L regions and over all the SAMPEX-covered local times. In addition to this newly discovered common feature of the main phase electron loss for all the storm events and at all L locations, some other properties of the electron loss rates, such as the local time and energy dependence that vary with time or locations, were also estimated and discussed. This method combining model with the low-altitude observations provides direct quantification of the electron loss rate, a prerequisite for any comprehensive modeling of the radiation belt electron dynamics.

Silicate Phases on the Surfaces of Trojan Asteroids

NASA Astrophysics Data System (ADS)

Martin, Audrey; Emery, Joshua P.; Lindsay, Sean S.

2017-10-01

Determining the origin of asteroids provides an effective means of constraining the solar system’s dynamic past. Jupiter Trojan asteroids (hereafter Trojans) may help in determining the amount of radial mixing that occurred during giant planet migration. Previous studies aimed at characterizing surface composition show that Trojans have low albedo surfaces and are spectrally featureless in the near infrared. The thermal infrared (TIR) wavelength range has advantages for detecting silicates on low albedo asteroids such as Trojans. The 10 μm region exhibits strong features due to the Si-O fundamental molecular vibrations. Silicates that formed in the inner solar system likely underwent thermal annealing, and thus are crystalline, whereas silicates that accreted in the outer solar system experienced less thermal processing, and therefore are more likely to have remained in an amorphous phase. We hypothesize that the Trojans formed in the outer solar system (i.e., the Kuiper Belt), and therefore will have a more dominant amorphous spectral silicate component. With TIR spectra from the Spitzer Space Telescope, we identify mineralogical features from the surface of 11 Trojan asteroids. Fine-grain mixtures of crystalline pyroxene and olivine exhibit a 10 μm feature with sharp cutoffs between about 9 μm and 12 μm, which create a broad flat plateau. Amorphous phases, when present, smooth the sharp emission features, resulting in a dome-like shape. Preliminary results indicate that the surfaces of analyzed Trojans contain primarily amorphous silicates. Emissivity spectra of asteroids 1986 WD and 4709 Ennomos include small peaks in the 10 μm region, diagnostic of small amounts of crystalline olivine. One explanation is that Trojans formed in the same region as Kuiper Belt objects, and when giant planet migration ensued, they were swept into Jupiter’s stable Lagrange points where they are found today. As such, it is possible that an ancestral group of Kuiper Belt objects were separated from Trojans during large planet migration.

Variations in the width of the Indo-Pacific tropical rain belt over the last millennium: synthesis of stalagmite proxy records and climate model simulations

NASA Astrophysics Data System (ADS)

Ummenhofer, Caroline; Denniston, Rhawn

2017-04-01

The seasonal north-south migration of the intertropical convergence zone defines the tropical rain belt (TRB), a region of enormous terrestrial biodiversity and home to 40% of the world's population. The TRB is dynamic and has been shown to shift south as a coherent system during periods of Northern Hemisphere cooling. However, recent studies of Indo-Pacific hydroclimate suggest that during the Little Ice Age (AD 1400-1850), the TRB in this region contracted rather than being displaced uniformly southward. This behaviour is not well understood, particularly during climatic fluctuations less pronounced than those of the Little Ice Age, the largest centennial-scale cool period of the last millennium. Using state-of-the-art climate model simulations conducted as part of the Last Millennium Ensemble with the Community Earth System Model (CESM), we evaluate variations in the width of the Indo-Pacific TRB, as well as movements in the position of its northward and southward edges, across a range of timescales over the pre-Industrial portion of the last millennium (AD 850-1850). The climate model results complement a recent reconstruction of late Holocene variability of the Indo-Pacific TRB, based on a precisely-dated, monsoon-sensitive stalagmite reconstruction from northern Australia (cave KNI-51), located at the southern edge of the TRB and thus highly sensitive to variations at its southern edge. Integrating KNI-51 with a record from Dongge Cave in southern China allows a stalagmite-based TRB reconstruction. Our results reveal that rather than shifting meridionally, the Indo-Pacific TRB expanded and contracted over multidecadal/centennial time scales during the late Holocene, with symmetric weakening/strengthening of summer monsoons in the Northern and Southern Hemispheres of the Indo-Pacific (the East Asian summer monsoon in China and the Australian summer monsoon in northern Australia). Links to large-scale climatic conditions across the Indo-Pacific region, including its leading modes of variability, are made in the climate model simulations to elucidate the dynamics of TRB variations during periods of expansion and contraction over the last millennium.

Spacing of Imbricated Thrust Faults and the Strength of Thrust-Belts and Accretionary Wedges

NASA Astrophysics Data System (ADS)

Ito, G.; Regensburger, P. V.; Moore, G. F.

2017-12-01

The pattern of imbricated thrust blocks is a prominent characteristic of the large-scale structure of thrust-belts and accretionary wedges around the world. Mechanical models of these systems have a rich history from laboratory analogs, and more recently from computational simulations, most of which, qualitatively reproduce the regular patterns of imbricated thrusts seen in nature. Despite the prevalence of these patterns in nature and in models, our knowledge of what controls the spacing of the thrusts remains immature at best. We tackle this problem using a finite difference, particle-in-cell method that simulates visco-elastic-plastic deformation with a Mohr-Coulomb brittle failure criterion. The model simulates a horizontal base that moves toward a rigid vertical backstop, carrying with it an overlying layer of crust. The crustal layer has a greater frictional strength than the base, is cohesive, and is initially uniform in thickness. As the layer contracts, a series of thrust blocks immerge sequentially and form a wedge having a mean taper consistent with that predicted by a noncohesive, critical Coulomb wedge. The widths of the thrust blocks (or spacing between adjacent thrusts) are greatest at the front of the wedge, tend to decrease with continued contraction, and then tend toward a pseudo-steady, minimum width. Numerous experiments show that the characteristic spacing of thrusts increases with the brittle strength of the wedge material (cohesion + friction) and decreases with increasing basal friction for low (<8°) taper angles. These relations are consistent with predictions of the elastic stresses forward of the frontal thrust and at what distance the differential stress exceeds the brittle threshold to form a new frontal thrust. Hence the characteristic spacing of the thrusts across the whole wedge is largely inherited at the very front of the wedge. Our aim is to develop scaling laws that will illuminate the basic physical processes controlling systems, as well as allow researchers to use observations of thrust spacing as an independent constraint on the brittle strength of wedges as well as their bases.

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.

Interference in the gg→h→γγ On-Shell Rate and the Higgs Boson Total Width.

PubMed

Campbell, John; Carena, Marcela; Harnik, Roni; Liu, Zhen

2017-11-03

We consider interference between the Higgs signal and QCD background in gg→h→γγ and its effect on the on-shell Higgs rate. The existence of sizable strong phases leads to destructive interference of about 2% of the on-shell cross section in the standard model. This effect can be enhanced by beyond the standard model physics. In particular, since it scales differently from the usual rates, the presence of interference allows indirect limits to be placed on the Higgs width in a novel way, using on-shell rate measurements. Our study motivates further QCD calculations to reduce uncertainties. We discuss possible width-sensitive observables, both using total and differential rates and find that the HL-LHC can potentially indirectly constrain widths of order tens of MeV.

Acoustically Evoked Different Vibration Pattern Across the Width of the Cochlea Partition

NASA Astrophysics Data System (ADS)

Zha, Dingjun; Chen, Fangyi; Friderberg, Anders; Choudhury, Niloy; Nuttall, Alfred

2011-11-01

Using optical low coherence interferometry, the acoustically evoked vibration patterns of the basilar membrane (BM) and reticular lamina (RL) in the first turn of living guinea pigs were measured as function of the radial location. It was demonstrated that the vibration of the BM varied widely in amplitude, but little in phase across the width of the partition, while the RL had a different vibration pattern compared with the BM.

Computational And Experimental Studies Of Three-Dimensional Flame Spread Over Liquid Fuel Pools

NASA Technical Reports Server (NTRS)

Ross, Howard D. (Technical Monitor); Cai, Jinsheng; Liu, Feng; Sirignano, William A.; Miller, Fletcher J.

2003-01-01

Schiller, Ross, and Sirignano (1996) studied ignition and flame spread above liquid fuels initially below the flashpoint temperature by using a two-dimensional computational fluid dynamics code that solves the coupled equations of both the gas and the liquid phases. Pulsating flame spread was attributed to the establishment of a gas-phase recirculation cell that forms just ahead of the flame leading edge because of the opposing effect of buoyancy-driven flow in the gas phase and the thermocapillary-driven flow in the liquid phase. Schiller and Sirignano (1996) extended the same study to include flame spread with forced opposed flow in the gas phase. A transitional flow velocity was found above which an originally uniform spreading flame pulsates. The same type of gas-phase recirculation cell caused by the combination of forced opposed flow, buoyancy-driven flow, and thermocapillary-driven concurrent flow was responsible for the pulsating flame spread. Ross and Miller (1998) and Miller and Ross (1998) performed experimental work that corroborates the computational findings of Schiller, Ross, and Sirignano (1996) and Schiller and Sirignano (1996). Cai, Liu, and Sirignano (2002) developed a more comprehensive three-dimensional model and computer code for the flame spread problem. Many improvements in modeling and numerical algorithms were incorporated in the three-dimensional model. Pools of finite width and length were studied in air channels of prescribed height and width. Significant three-dimensional effects around and along the pool edge were observed. The same three-dimensional code is used to study the detailed effects of pool depth, pool width, opposed air flow velocity, and different levels of air oxygen concentration (Cai, Liu, and Sirignano, 2003). Significant three-dimensional effects showing an unsteady wavy flame front for cases of wide pool width are found for the first time in computation, after being noted previously by experimental observers (Ross and Miller, 1999). Regions of uniform and pulsating flame spread are mapped for the flow conditions of pool depth, opposed flow velocity, initial pool temperature, and air oxygen concentration under both normal and microgravity conditions. Details can be found in Cai et al. (2002, 2003). Experimental results recently performed at NASA Glenn of flame spread across a wide, shallow pool as a function of liquid temperature are also presented here.

Phase field study of surface-induced melting and solidification from a nanovoid: Effect of dimensionless width of void surface and void size

NASA Astrophysics Data System (ADS)

Basak, Anup; Levitas, Valery I.

2018-05-01

The size effect and the effects of a finite-width surface on barrierless transformations between the solid (S), surface melt (SM), and melt (M) from a spherical nanovoid are studied using a phase field approach. Melting (SM → M and S → M) from the nanovoid occurs at temperatures which are significantly greater than the solid-melt equilibrium temperature θe but well below the critical temperature for solid instability. The relationships between the SM and M temperatures and the ratio of the void surface width and width of the solid-melt interface, Δ ¯ , are found for the nanovoids of different sizes. Below a critical ratio Δ¯ * , the melting occurs via SM and the melting temperature slightly reduces with an increase in Δ ¯ . Both S → SM and SM → M transformations have a jump-like character (excluding the case with the sharp void surface), causing small temperature hysteresis. However, the solid melts without SM for Δ ¯>Δ¯ * , and the melting temperature significantly increases with increasing Δ ¯ . The results for a nanovoid are compared with the melting/solidification of a nanoparticle, for which the melting temperatures, in contrast, are much lower than θe. A linear dependency of the melting temperatures with the inverse of the void radius is shown. The present study shows an unexplored way to control the melting from nanovoids by controlling the void size and the width and energy of the surface.

Distant asteroids and Chiron

NASA Technical Reports Server (NTRS)

French, Linda M.; Vilas, Faith; Hartmann, William K.; Tholen, David J.

1989-01-01

Knowledge of the physical properties of distant asteroids (a greater than 3.3 AU) has grown dramatically over the past five years, due to systematic compositional and lighcurve studies. Most of these objects have red, dark surfaces, and their spectra show a reddening in spectral slope with heliocentric distance, implying a change in surface composition. Trojans for which near-opposition phase curve information is available appear to show little or no opposition effect, unlike any other dark solar system objects. The lightcurve amplitudes of Trojan and Hilda asteroids imply significantly more elongated shapes for these groups than for main-belt asteroids of comparable size. These recent observations are reviewed in the context of their implications for the formationan and subsequent evolution of the distant asteroids, and their interrelations with the main belt, Chiron, and comets.

Call for NASA Mission Supporting Observations

NASA Astrophysics Data System (ADS)

Binzel, Richard P.

2018-04-01

Lightcurve observations are requested to support NASA missions planned for launch to study main-belt and Trojan asteroids. In some cases, the rotations of the target asteroids are unknown. In other cases, the periods are well established and ongoing measurements will deliver the precision needed to deduce the rotation phase at the time of encounter more than a decade away.

A phase I/II clinical trial for the hybrid of intracavitary and interstitial brachytherapy for locally advanced cervical cancer.

PubMed

Murakami, Naoya; Kato, Shingo; Nakano, Takashi; Uno, Takashi; Yamanaka, Takeharu; Sakurai, Hideyuki; Yoshimura, Ryoichi; Hiratsuka, Junichi; Kuroda, Yuki; Yoshio, Kotaro; Itami, Jun

2016-08-17

This paper describes about a study protocol of phase I/II multicenter prospective clinical trial evaluating the feasibility and efficacy of the hybrid of intracavitary and interstitial brachytherapy (HBT) for locally advanced uterine cervical cancer patients. Patients with histologically confirmed FIGO stage IB2, IIA2, IIB, and IIIB uterine cervical carcinoma width of which is larger than 5 cm assessed by MRI will be entered to this clinical trial. Protocol therapy is 30-30.6 Gy in 15-17 fractions of whole pelvic radiotherapy concurrent with weekly CDDP (40 mg/m(2)), followed by 24 Gy in 4 fractions of HBT and central shield EBRT up to 50-50.4 Gy in 25-28 fractions. Tumor width is assessed again within one week before the first HBT and if the tumor width is larger than 4 cm, patients proceed to the secondary registration. In phase I section, feasibility of this will be investigated. If less than 10 % out of 20 patients experienced greater than grade 3 acute non-hematologic adverse effects, the study proceeds to phase II part. In phase II part a total of 55 patients will be accrued and the efficacy of the HBT will be investigated comparing with historical control data. If the lower margin of 90 % confidence interval of the 2-year pelvic progression-free survival of the HBT trial is higher than 64 %, the HBT is considered to be more effective than conventional ICBT. The aim of this study is to demonstrate the feasibility and efficacy of the HBT for locally advanced cervical cancer. This trial will clarify the indication, feasibility, and efficacy of this new technique. UMIN000019081 ; Registration date: 2015/9/30.

Self-organization of linear nanochannel networks

NASA Astrophysics Data System (ADS)

Annabattula, R. K.; Veenstra, J. M.; Mei, Y. F.; Schmidt, O. G.; Onck, P. R.

2010-06-01

A theoretical study has been conducted to explore the mechanics of self-organizing channel networks with dimensions in the submicron range and nanorange. The channels form by the partial release and bond back of prestressed thin films. In the release phase, the film spontaneously buckles into wrinkles of a certain wavelength, followed by a bond-back phase in which the final channel geometry is established through cohesive interface attractions. Results are presented in terms of the channel spacing, height, and width as a function of the film stiffness, thickness, eigenstrain, etch width, and interface energy. We have identified two dimensionless parameters that fully quantify the network assembly, showing excellent agreement with experiments. Our results provide valuable insight for the design of submicron and nanoscale channel networks with specific geometries.

Use of seatbelts in cars with automatic belts.

PubMed Central

Williams, A F; Wells, J K; Lund, A K; Teed, N J

1992-01-01

Use of seatbelts in late model cars with automatic or manual belt systems was observed in suburban Washington, DC, Chicago, Los Angeles, and Philadelphia. In cars with automatic two-point belt systems, the use of shoulder belts by drivers was substantially higher than in the same model cars with manual three-point belts. This finding was true in varying degrees whatever the type of automatic belt, including cars with detachable nonmotorized belts, cars with detachable motorized belts, and especially cars with nondetachable motorized belts. Most of these automatic shoulder belts systems include manual lap belts. Use of lap belts was lower in cars with automatic two-point belt systems than in the same model cars with manual three-point belts; precisely how much lower could not be reliably estimated in this survey. Use of shoulder and lap belts was slightly higher in General Motors cars with detachable automatic three-point belts compared with the same model cars with manual three-point belts; in Hondas there was no difference in the rates of use of manual three-point belts and the rates of use of automatic three-point belts. PMID:1561301

Plume magmatism and crustal growth at 2.9 to 3.0 Ga in the Steep Rock and Lumby Lake area, Western Superior Province

NASA Astrophysics Data System (ADS)

Tomlinson, K. Y.; Hughes, D. J.; Thurston, P. C.; Hall, R. P.

1999-01-01

The greenstone belts of the western Superior Province are predominantly 2.78 to 2.69 Ga and provide evidence of oceanic and arc volcanism during the accretionary phase of development of the Superior Province. There is also scattered evidence of Meso-Archean crust (predominantly 2.9 to 3.0 Ga) within the western Superior Province. The Meso-Archean greenstone belts commonly contain platformal sediments and unconformably overlie granitoid basement. The platformal sediments occur associated with komatiitic and tholeiitic volcanic rocks that suggest a history of magmatism associated with rifting during the Meso-Archean. The central Wabigoon Subprovince is a key area of Meso-Archean crust and in its southern portion comprises the Steep Rock, Finlayson and Lumby Lake greenstone belts. The Steep Rock greenstone belt unconformably overlies 3 Ga continental basement and contains platformal sediments succeeded by komatiitic and tholeiitic volcanic rocks. The Lumby Lake greenstone belt contains thick sequences of mafic volcanics, a number of komatiite horizons, and thin platformal sedimentary units. The two belts are joined by the predominantly mafic volcanic Finlayson greenstone belt. The volcanics throughout these three greenstone belts may be correlated to some extent and a range of basaltic and komatiite types is present. Al-undepleted komatiites present in the Lumby Lake greenstone belt have an Al 2O 3/TiO 2 ratio ranging from 14 to 27 and (Gd/Yb) N from 0.7 to 1.3. These are divided into basaltic komatiites with generally unfractionated mantle-normalised multi-element profiles, and spinifex-textured high-Mg basalts with slightly light REE enriched multi-element profiles and small negative Nb and Ta anomalies. The unfractionated basaltic komatiites represent high degree partial melts of the upper mantle whereas the spinifex-textured high-Mg basalts represent evolutionary products of the komatiite liquids following olivine and chromite fractionation and crustal contamination. Al-depleted komatiites are present in both the Lumby Lake and Steep Rock belts and have Al 2O 3/TiO 2 ratio ranges from 2.5 to 5. These display strong enrichment in the light REE and Nb and strong depletion in the heavy REE and Y ((Gd/Yb) N=2-4). They represent a deep mantle plume source generated from a high degree of partial melting in the majorite garnet stability field. The basaltic flows in all three greenstone belts are predominantly slightly light REE depleted and represent a slightly depleted upper mantle source. Basalts spatially associated with the unfractionated basaltic komatiites and the slightly light REE enriched spinifex-textured high-Mg basalts are also slightly enriched in light REE and have negative Nb and Ta anomalies. These basalts represent evolved products of the primitive basaltic komatiites and enriched spinifex-textured high-Mg basalts after further crustal contamination and olivine and clinopyroxene fractionation. The geochemical stratigraphy in the Lumby Lake belt is consistent with an ascending mantle plume model. The light REE depleted basalts were derived from upper mantle melted by an ascending mantle plume. These are overlain by the unfractionated basaltic komatiites and their evolutionary products which represent hotter plume head material derived from a mixture of plume mantle and entrained depleted upper mantle. In turn, these are overlain by strongly light REE and HFSE enriched komatiites that represent a deep plume source that has not been mixed with depleted mantle and are, therefore, likely to have been derived from a plume core or tail. Volcanism was protracted in these three greenstone belts lasting ca. 70 Ma and combined stratigraphic evidence from the Lumby Lake and Steep Rock belts suggests that more than one plume may have ascended and tapped the same mantle sources, over time, within the area. Plume magmatism and rifting of continental platforms thus appears to have been an important feature of crustal development in the Meso-Archean.

Generation of ultra-long pure magnetization needle and multiple spots by phase modulated doughnut Gaussian beam

NASA Astrophysics Data System (ADS)

Udhayakumar, M.; Prabakaran, K.; Rajesh, K. B.; Jaroszewicz, Z.; Belafhal, Abdelmajid; Velauthapillai, Dhayalan

2018-06-01

Based on vector diffraction theory and inverse Faraday effect (IFE), the light induced magnetization distribution of a tightly focused azimuthally polarized doughnut Gaussian beam superimposed with a helical phase and modulated by an optimized multi belt complex phase filter (MBCPF) is analysed numerically. It is noted that by adjusting the radii of different rings of the complex phase filter, one can achieve many novel magnetization focal distribution such as sub wavelength scale (0.29λ) and super long (52.2λ) longitudinal magnetic probe suitable for all optical magnetic recording and the formation of multiple magnetization chain with four, six and eight sub-wavelength spherical magnetization spots suitable for multiple trapping of magnetic particles are achieved.

Violation of the entanglement area law in bosonic systems with Bose surfaces: possible application to Bose metals.

PubMed

Lai, Hsin-Hua; Yang, Kun; Bonesteel, N E

2013-11-22

We show the violation of the entanglement area law for bosonic systems with Bose surfaces. For bosonic systems with gapless factorized energy dispersions on an N(d) Cartesian lattice in d dimensions, e.g., the exciton Bose liquid in two dimensions, we explicitly show that a belt subsystem with width L preserving translational symmetry along d-1 Cartesian axes has leading entanglement entropy (N(d-1)/3)lnL. Using this result, the strong subadditivity inequality, and lattice symmetries, we bound the entanglement entropy of a rectangular subsystem from below and above showing a logarithmic violation of the area law. For subsystems with a single flat boundary, we also bound the entanglement entropy from below showing a logarithmic violation, and argue that the entanglement entropy of subsystems with arbitrary smooth boundaries are similarly bounded.

Length scales and pinning of interfaces

PubMed Central

Tan, Likun

2016-01-01

The pinning of interfaces and free discontinuities by defects and heterogeneities plays an important role in a variety of phenomena, including grain growth, martensitic phase transitions, ferroelectricity, dislocations and fracture. We explore the role of length scale on the pinning of interfaces and show that the width of the interface relative to the length scale of the heterogeneity can have a profound effect on the pinning behaviour, and ultimately on hysteresis. When the heterogeneity is large, the pinning is strong and can lead to stick–slip behaviour as predicted by various models in the literature. However, when the heterogeneity is small, we find that the interface may not be pinned in a significant manner. This shows that a potential route to making materials with low hysteresis is to introduce heterogeneities at a length scale that is small compared with the width of the phase boundary. Finally, the intermediate setting where the length scale of the heterogeneity is comparable to that of the interface width is characterized by complex interactions, thereby giving rise to a non-monotone relationship between the relative heterogeneity size and the critical depinning stress. PMID:27002068

Novel ultra-short and ultra-broadband polarization beam splitter based on a bent directional coupler.

PubMed

Dai, Daoxin; Bowers, John E

2011-09-12

A novel ultra-short polarization beam splitter (PBS) based on a bent directional coupler is proposed by utilizing the evanescent coupling between two bent optical waveguides with different core widths. For the bent directional coupler, there is a significant phase-mismatch for TE polarization while the phase-matching condition is satisfied for TM polarization. Therefore, the TM polarized light can be coupled from the narrow input waveguide to the adjacent wide waveguide while the TE polarization goes through the coupling region without significant coupling. An ultra-short (<10 μm-long) PBS is designed based on silicon-on-insulator nanowires and the length of the bent coupling region is as small as 4.5 μm while the gap width is chosen as 200 nm (large enough to simplify the fabrication). Numerical simulations show that the present PBS has a good fabrication tolerance for the variation of the waveguide width (more than ± 60 nm) and a very broad band (~200 nm) for an extinction ratio of >10 dB.

Design and Simulation of Control Technique for Permanent Magnet Synchronous Motor Using Space Vector Pulse Width Modulation

NASA Astrophysics Data System (ADS)

Khan, Mansoor; Yong, Wang; Mustafa, Ehtasham

2017-07-01

After the rapid advancement in the field of power electronics devices and drives for last few decades, there are different kinds of Pulse Width Modulation techniques which have been brought to the market. The applications ranging from industrial appliances to military equipment including the home appliances. The vey common application for the PWM is three phase voltage source inverter, which is used to convert DC to AC in the homes to supply the power to the house in case electricity failure, usually named as Un-interrupted Power Supply. In this paper Space Vector Pulse Width Modulation techniques is discussed and analysed under the control technique named as Field Oriented Control. The working and implementation of this technique has been studied by implementing on the three phase bridge inverter. The technique is used to control the Permanente Magnet Synchronous Motor. The drive system is successfully implemented in MATLAB/Simulink using the mathematical equation and algorithm to achieve the satisfactory results. PI type of controller is used to tuned ers of the motothe parametr i.e. torque and current.

Selective two-photon excitation of a vibronic state by correlated photons.

PubMed

Oka, Hisaki

2011-03-28

We theoretically investigate the two-photon excitation of a molecular vibronic state by correlated photons with energy anticorrelation. A Morse oscillator having three sets of vibronic states is used, as an example, to evaluate the selectivity and efficiency of two-photon excitation. We show that a vibrational mode can be selectively excited with high efficiency by the correlated photons, without phase manipulation or pulse-shaping techniques. This can be achieved by controlling the quantum correlation so that the photon pair concurrently has two pulse widths, namely, a temporally narrow width and a spectrally narrow width. Though this concurrence is seemingly contradictory, we can create such a photon pair by tailoring the quantum correlation between two photons.

Convergent Plate Boundary Processes in the Archean: Evidence from Greenland

NASA Astrophysics Data System (ADS)

Polat, A.

2014-12-01

The structural, magmatic and metamorphic characteristics of Archean greenstone belts and associated TTG (tonalite, trondhjemite and granodiorite) gneisses in southern West Greenland are comparable to those of Phanerozoic convergent plate margins, suggesting that Archean continents grew mainly at subduction zones. These greenstone belts are composed mainly of tectonically juxtaposed fragments of oceanic crust including mafic to ultramafic rocks, with minor sedimentary rocks. Volcanic rocks in the greenstone belts are characterized mainly by island arc tholeiitic basalts, picrites, and boninites. The style of deformation and geometry of folds in 10 cm to 5 m wide shear zones are comparable to those occur on 1 to 50 km scale in the greenstone belts and TTG gneisses, suggesting that compressional tectonic processes operating at convergent plate boundaries were the driving force of Archean crustal accretion and growth. Field observations and trace element data suggest that Archean continental crust grew through accretion of mainly island arcs and melting of metamorphosed mafic rocks (amphibolites) in thickened arcs during multiple tectonothermal events. Fold patterns on cm to km scale are consistent with at least three phases of deformation and multiple melting events generating TTG melts that intruded mainly along shear zones in accretionary prism and magmatic arcs. It is suggested that Archean TTGs were produced by three main processes: (1) melting of thickened oceanic island arcs; (2) melting of subducted oceanic crust; and (3) differentiation of basaltic melts originating from metasomatized sub-arc mantle wedge peridotites.

The Generation of the Distant Kuiper Belt by Planet Nine from an Initially Broad Perihelion Distribution

NASA Astrophysics Data System (ADS)

Khain, Tali; Batygin, Konstantin; Brown, Michael E.

2018-04-01

The observation that the orbits of long-period Kuiper Belt objects are anomalously clustered in physical space has recently prompted the Planet Nine hypothesis - the proposed existence of a distant and eccentric planetary member of our Solar System. Within the framework of this model, a Neptune-like perturber sculpts the orbital distribution of distant Kuiper Belt objects through a complex interplay of resonant and secular effects, such that the surviving orbits get organized into apsidally aligned and anti-aligned configurations with respect to Planet Nine's orbit. We present results on the role of Kuiper Belt initial conditions on the evolution of the outer Solar System using numerical simulations. Intriguingly, we find that the final perihelion distance distribution depends strongly on the primordial state of the system, and demonstrate that a bimodal structure corresponding to the existence of both aligned and anti-aligned clusters is only reproduced if the initial perihelion distribution is assumed to extend well beyond 36 AU. The bimodality in the final perihelion distance distribution is due to the permanently stable objects, with the lower perihelion peak corresponding to the anti-aligned orbits and the higher perihelion peak corresponding to the aligned orbits. We identify the mechanisms that enable the persistent stability of these objects and locate the regions of phase space in which they reside. The obtained results contextualize the Planet Nine hypothesis within the broader narrative of solar system formation, and offer further insight into the observational search for Planet Nine.

High-risk behaviors while driving: A population-based study from Iran.

PubMed

Khadem-Rezaiyan, Majid; Moallem, Seyed Reza; Vakili, Veda

2017-04-03

Traffic injuries are becoming one of the most important challenges of public health systems. Because these injuries are mostly preventable, the aim of this study is to evaluate the four main high-risk behaviors while driving. This cross-sectional study was conducted on a random sample from the population of Mashhad, Iran, in 2014. A checklist and a previously validated questionnaire for the transtheoretical stages of change model (TTM) were used for data collection. Statistical analyses were performed using SPSS 11.5 software with P <.05 statistically significant. Totally 431 individuals were included with a mean age of 30 ± 11.3 years. Forty-three percent (183) were male. The TTM model revealed that participants were mostly in pre-actional phases regarding not using a cell phone while driving (80%), fastening the driver's seat belt (66%), front seat belt (68%), and rear seat belt (85%) The penalty was a protective factor only for using cellphone (odd ratio [OR] = 0.82, 95% confidence interval [CI], 0.68-0.98). Lower education (OR = 0.12, 95% CI, 0.01-0.94) and male gender (OR = 0.35, 95% CI, 0.14-0.83) were indicative of lower rates of fastening the front and rear seat belts. The stages of change model among study participants is a proper reflection of the effectiveness of the current policies. More serious actions regarding these high-risk behaviors should be considered in legislation.

THE EFFECT OF A PELVIC COMPRESSION BELT ON FUNCTIONAL HAMSTRING MUSCLE ACTIVITY IN SPORTSMEN WITH AND WITHOUT PREVIOUS HAMSTRING INJURY.

PubMed

Arumugam, Ashokan; Milosavljevic, Stephan; Woodley, Stephanie; Sole, Gisela

2015-06-01

There is evidence that applying a pelvic compression belt (PCB) can decrease hamstring and lumbar muscle electromyographic activity and increase gluteus maximus activity in healthy women during walking. Increased isokinetic eccentric hamstring strength in the terminal range (25 ° - 5 °) of knee extension has been reported with the use of such a belt in sportsmen with and without hamstring injuries. However, it is unknown whether wearing a pelvic belt alters activity of the hamstrings in sportsmen during walking. To examine the effects of wearing a PCB on electromyographic activity of the hamstring and lumbopelvic muscles during walking in sportsmen with and without hamstring injuries. Randomised crossover, cross-sectional study. Thirty uninjured sportsmen (23.53 ± 3.68 years) and 20 sportsmen with hamstring injuries (22.00 ± 1.45 years) sustained within the previous 12 months participated in this study. Electromyographic amplitudes of the hamstrings, gluteus maximus, gluteus medius and lumbar multifidus were monitored during defined phases of walking and normalised to maximum voluntary isometric contraction. Within-group comparisons [PCB vs. no PCB] for the normalised electromyographic amplitudes were performed for each muscle group using paired t tests. Electromyographic change scores [belt - no belt] were calculated and compared between the two groups with independent t tests. No significant change was evident in hamstring activity for either group while walking with the PCB (p > 0.050). However, with the PCB, gluteus medius activity (p ≤ 0.028) increased in both groups, while gluteus maximus activity increased (p = 0.025) and multifidus activity decreased (p < 0.001) in the control group. The magnitude of change induced by the PCB in gluteus medius activity was similar between groups (p = 0.760). No statistically significant baseline differences in no belt scores were evident between groups for the investigated muscles (p ≥ 0.050). Application of a PCB had individual-specific effects on electromyographic activity of injured and uninjured hamstrings during walking, resulting in no significant changes within or between the two groups. Future studies investigating effects of the PCB on hamstring activity in participants with acute injury and during a more demanding functional activity such as running are warranted. Level 3.

The Southeast Asian Tin Belt

NASA Astrophysics Data System (ADS)

Schwartz, M. O.; Rajah, S. S.; Askury, A. K.; Putthapiban, P.; Djaswadi, S.

1995-07-01

The Southeast Asian Tin Belt is a north-south elongate zone 2800 km long and 400 km wide, extending from Burma (Myanmar) and Thailand to Peninsular Malaysia and the Indonesian Tin Islands. Altogether 9.6 million tonnes of tin, equivalent to 54% of the world's tin production is derived from this region. Most of the granitoids in the region can be grouped geographically into elongate provinces or belts, based on petrographic and geochronological features. - The Main Range Granitoid Province in western Peninsular Malaysia, southern Peninsular Thailand and central Thailand is almost entirely made up of biotite granite (184-230 Ma). Tin deposits associated with these granites contributed 55% of the historic tin production of Southeast Asia. - The Northern Granitoid Province in northern Thailand (0.1% of tin production) also has dominant biotite granite (200-269 Ma) but it is distinguished by abundant post-intrusion deformation. - The Eastern Granitoid Province extends from eastern Peninsular Malaysia to eastern Thailand. The Malaysian part is subdivided into the East Coast Belt (220-263 Ma), Boundary Range Belt (197-257 Ma) and Central Belt (79-219 Ma). The granitoids cover a wide compositional range from biotite granite to hornblende-biotite granite/granodiorite and diorite-gabbro. Tin deposits are associated with biotite granite in the East Coast Belt (3% of tin production). The granitoids in the other areas of the Eastern Granitoid Province are barren. - The Western Granitoid Province (22-149 Ma) in northern Peninsular Thailand, western Thailand and Burma has biotite granite and hornblende-biotite granite/granodiorite. Tin deposits are associated with biotite granite, which probably is the dominant phase (14% of tin production). The granitoids of the Indonesian Tin Islands (193-251 Ma) do not permit grouping into geographically distinct units. Main Range-type and Eastern Province-type plutons occur next to each other. Most of the tin deposits are associated with Main Range-type plutons (28% of tin production). Tin-mineralized plutons are characterized by high concentrations of SiO 2, K 2O, Rb, Sn, Th and U, whereas the concentrations of Fe 2O 3, MgO, CaO, Na 2O, Ba and Sr as well as the Fe2O3/FeO ratios are low. Tin-mineralized plutons are also distinguished by high initial 87Sr/86Sr ratios low magnetic susceptibilities.

The Tintina Gold Belt - A global perspective

USGS Publications Warehouse

Goldfarb, Richard J.; Hart, Craig J.R.; Miller, Marti L.; Miller, Lance D.; Farmer, G. Lang; Groves, David I.; Tucker, Terry L.; Smith, Moira T.

2000-01-01

The so-called Tintina Gold Belt extends for more than 1000 km along the length of the northern North American Cordillera. Middle to Late Cretaceous Au deposits within the belt have various similar characteristics, among which are a spatial and temporal association with magmatism; Bi-W-Te signatures in deposits hosted by granitod stocks and As-Sb signatures where hosted by sedimentary rocks and dyke systems; and δ180 values consistently > 12 per mil for Au-bearing quartz. Nevertheless significant differences in structural styles, levels of deposit emplacement, ore-fluid chemistry, and Au grades suggest that the characteristics represent a broad range of deposit types. Many of these are best classified as orogenic Au deposits in the Yukon-Tanana terrane, as epithermal and porphyry-style Au deposits in the Kuskokwim region, and as Au-bearing, granite-related veins and stockworks, replacements, and skarns, as well as associated polymetallic lodes, in central Yukon. The diverse types of Au deposits and associated plutons of the Tintina Gold Belt collectively define a 45-m.y.-long period of arc magmatism that migrated northwesterly, for about 1000 km, across the active collisional margin of Cretaceous northwestern North America. The initiation of fluid flow and plutonism in Albian time seems to correlate with the onset of oblique subduction and dextral strike-slip on the Denali-Farewell, Tintina-Kaltag, and related fault systems. Initial Au-vein formation and subduction-related magmatism at about 115-110 Ma (e.g., including the Goodpaster and Fortymile districts), within the seaward side of the Yukon-Tanana terrane, correlate with the arrival of the Wrangellia superterrane off the continental margin. Dextral translation of the allochthonous Wrangellia block was associated with the migration of the thermal pulse to the northwest at about 95-90 Ma. Orogenic (or so­ called mesotherrnal) and granitoid-related Au deposits formed across the width of the Yukon-Tanana terrane (e.g., Fort Knox, True North, Ryan Lode, Kantishna district) and inland into the passive-margin rocks of the Selwyn basin ( e.g., Scheelite Dome, Brewery Creek, Dublin Gulch), respectively. By 70 Ma, the arc had migrated to the vicinity of present-day southwestern Alaska, where it was associated with the formation of additional orogenic Au deposits (e.g., Willow Creek district) and, within still-preserved shallow crustal levels, epithermal Au systems (e.g., Donlin Creek). The Au-bearing deposits of the Tintina Gold Belt are typical of those found in most well-preserved, moderate- to high-temperature Phanerozoic collisional orogens. Around the circum-Pacific region, these would include large areas of Mesozoic tectonism along the Cordilleran orogen, throughout the Russian Far East, and along the margins of the North China craton. Favorable terrain for such Au belts of Paleozoic age worldwide include the active Gondwana margins (e.g., Tasman orogenic system, northern Africa, Telfer district), and the northern margins ( e.g., Caledonian Kazakhstania, Uralian orogen, Baikal orogen, Tian Shan orogenic system) and western margins ( e.g., southern European massifs) to the Paleo-Tethys Ocean. Gold lodes in all of the Phanerozoic belts are dominated by orogenic Au-deposit types; other deposit types are concentrated where relatively shallow levels to the orogens are locally preserved. A significant percentage of the lode-gold resource in many areas was lost to placer accumulation that began forming approximately 100 m.y. after hypogene ore formation, except where continent-continent collision "cratonized" highly mineralized terranes in central Asia.

JunoCam Images of Jupiter: Science from an Outreach Experiment

NASA Astrophysics Data System (ADS)

Hansen, C. J.; Orton, G. S.; Caplinger, M. A.; Ravine, M. A.; Rogers, J.; Eichstädt, G.; Jensen, E.; Bolton, S. J.; Momary, T.; Ingersoll, A. P.

2017-12-01

The Juno mission to Jupiter carries a visible imager on its payload primarily for outreach, and also very useful for jovian atmospheric science. Lacking a formal imaging science team, members of the public have volunteered to process JunoCam images. Lightly processed and raw JunoCam data are posted on the JunoCam webpage at https://missionjuno.swri.edu/junocam/processing. Citizen scientists download these images and upload their processed contributions. JunoCam images through broadband red, green and blue filters and a narrowband methane filter centered at 889 nm mounted directly on the detector. JunoCam is a push-frame imager with a 58 deg wide field of view covering a 1600 pixel width, and builds the second dimension of the image as the spacecraft rotates. This design enables capture of the entire pole of Jupiter in a single image at low emission angle when Juno is 1 hour from perijove (closest approach). At perijove the wide field of view images are high-resolution while still capturing entire storms, e.g. the Great Red Spot. Juno's unique polar orbit yields polar perspectives unavailable to earth-based observers or most previous spacecraft. The first discovery was that the familiar belt-zone structure gives way to more chaotic storms, with cyclones grouped around both the north and south poles [1, 2]. Recent time-lapse sequences have enabled measurement of the rotation rates and wind speeds of these circumpolar cyclones [3]. Other topics are being investigated with substantial, in many cases essential, contributions from citizen scientists. These include correlating the high resolution JunoCam images to storms and disruptions of the belts and zones tracked throughout the historical record. A phase function for Jupiter is being developed empirically to allow image brightness to be flattened from the subsolar point to the terminator. We are studying high hazes and the stratigraphy of the upper atmosphere, utilizing the methane filter, structures illuminated beyond the terminator, and clouds casting shadows. Numerous high altitude clouds have been detected and we are investigating whether they are the jovian equivalent of squall lines. [1] Bolton, S. et al. (2017) Science 356:821; [2] Orton, G. et al. (2017) GRL 44:4599; [3] Adriani, A. et al. (2017) submitted to Nature.

Coherently Coupled ZnO and VO2 Interface studied by Photoluminescence and electrical transport across a phase transition

NASA Astrophysics Data System (ADS)

Srivastava, Amar; Saha, S.; Annadi, A.; Zhao, Y. L.; Gopinadhan, K.; Wang, X.; Naomi, N.; Liu, Z. Q.; Dhar, S.; Herng, T. S.; Nina, Bao; Ariando, -; Ding, Jun; Venkatesan, T.

2012-02-01

In this work we report a study of a coherently coupled interface consisting of a ZnO layer grown on top of an oriented VO2 layer on sapphire by photoluminescence and electrical transport measurements across the VO2 metal insulator phase transition (MIT). The photoluminescence of the ZnO layer showed a broad hysteresis induced by the phase transition of VO2 while the width of the electrical hysteresis was narrow and unaffected by the over layer. The enhanced width of the PL hysteresis was due to the formation of defects during the MIT as evidenced by a broad hysteresis in the opposite direction to that of the band edge PL in the defect luminescense. Unlike VO2 the defects in ZnO did not fully recover across the phase transition. From the defect luminescence data, oxygen interstitials were found to be the predominant defects in ZnO mediated by the strain from the VO2 phase transition. Such coherently coupled interfaces could be of use in characterizing the stability of a variety of interfaces and also for novel device application.

Trace element behavior and P-T-t evolution during partial melting of exhumed eclogite in the North Qaidam UHPM belt (NW China): Implications for adakite genesis

NASA Astrophysics Data System (ADS)

Zhang, Guibin; Niu, Yaoling; Song, Shuguang; Zhang, Lifei; Tian, Zuolin; Christy, Andrew G.; Han, Lei

2015-06-01

We have studied trace element behavior and timing of decompression melting of UHP rocks during exhumation recorded in the magmatic products, i.e., the melt phase (leucosomes), cumulate (garnetite) and residue (amphibolitized eclogite) from a single outcrop in the south Dulan area, North Qaidam UHPM belt, NW China. Two distinct episodes of partial melting are recognized. First, Grt-free tonalitic-trondhjemitic leucosome melts with higher silica crystallized at 424.0 ± 2.7 Ma. Garnets grew in the leucosome melt but fractionated out to form garnetite cumulates along with Ti-rich phases (rutile and titanite), strengthening the adakitic signature of the leucosome. Later Grt-bearing leucosome melts with an age of 412.4 ± 2.9 Ma cross-cut boudins and layers of amphibolitized eclogite. Geochemical investigation of bulk-rocks and in situ minerals verifies the genetic relationship between the amphibolitized eclogite and the tonalitic-trondhjemitic melts. Zircons from the amphibolitized eclogite have older (> 700 Ma) protolith ages, with subsequent eclogite-facies metamorphism, retrograde granulite-facies overprinting and partial melting. Phase modeling and Zr-in-rutile thermometry calculations in combination with zircon geochronology reveal the evolution P-T-t path for the exhumation and the partial melting of the deeply subducted continental crust at the North Qaidam subduction zone in the Early Paleozoic.

Interference in the g g → h → γ γ On-Shell Rate and the Higgs Boson Total Width

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

Campbell, John; Carena, Marcela; Harnik, Roni

We consider interference between the Higgs signal and QCD background inmore » $$gg\\rightarrow h \\rightarrow \\gamma\\gamma$$ and its effect on the on-shell Higgs rate. The existence of sizable strong phases leads to destructive interference of about 2% of the on-shell cross section in the Standard Model. This effect can be enhanced by beyond the standard model physics. In particular, since it scales differently from the usual rates, the presence of interference allows indirect limits to be placed on the Higgs width in a novel way, using on-shell rate measurements. Our study motivates further QCD calculations to reduce uncertainties. We discuss potential width-sensitive observables, both using total and differential rates and find that the HL-LHC can potentially indirectly probe widths of order tens of MeV.« less

Cavity mode-width spectroscopy with widely tunable ultra narrow laser.

PubMed

Cygan, Agata; Lisak, Daniel; Morzyński, Piotr; Bober, Marcin; Zawada, Michał; Pazderski, Eugeniusz; Ciuryło, Roman

2013-12-02

We explore a cavity-enhanced spectroscopic technique based on determination of the absorbtion coefficient from direct measurement of spectral width of the mode of the optical cavity filled with absorbing medium. This technique called here the cavity mode-width spectroscopy (CMWS) is complementary to the cavity ring-down spectroscopy (CRDS). While both these techniques use information on interaction time of the light with the cavity to determine absorption coefficient, the CMWS does not require to measure very fast signals at high absorption conditions. Instead the CMWS method require a very narrow line width laser with precise frequency control. As an example a spectral line shape of P7 Q6 O₂ line from the B-band was measured with use of an ultra narrow laser system based on two phase-locked external cavity diode lasers (ECDL) having tunability of ± 20 GHz at wavelength range of 687 to 693 nm.

Invalidity of the Fermi liquid theory and magnetic phase transition in quasi-1D dopant-induced armchair-edged graphene nanoribbons

NASA Astrophysics Data System (ADS)

Hoi, Bui Dinh; Davoudiniya, Masoumeh; Yarmohammadi, Mohsen

2018-04-01

Based on theoretically tight-binding calculations considering nearest neighbors and Green's function technique, we show that the magnetic phase transition in both semiconducting and metallic armchair graphene nanoribbons with width ranging from 9.83 Å to 69.3 Å would be observed in the presence of injecting electrons by doping. This transition is explained by the temperature-dependent static charge susceptibility through calculation of the correlation function of charge density operators. This work showed that charge concentration of dopants in such system plays a crucial role in determining the magnetic phase. A variety of multicritical points such as transition temperatures and maximum susceptibility are compared in undoped and doped cases. Our findings show that there exist two different transition temperatures and maximum susceptibility depending on the ribbon width in doped structures. Another remarkable point refers to the invalidity (validity) of the Fermi liquid theory in nanoribbons-based systems at weak (strong) concentration of dopants. The obtained interesting results of magnetic phase transition in such system create a new potential for magnetic graphene nanoribbon-based devices.

Drude weight fluctuations in many-body localized systems

NASA Astrophysics Data System (ADS)

Filippone, Michele; Brouwer, Piet W.; Eisert, Jens; von Oppen, Felix

2016-11-01

We numerically investigate the distribution of Drude weights D of many-body states in disordered one-dimensional interacting electron systems across the transition to a many-body localized phase. Drude weights are proportional to the spectral curvatures induced by magnetic fluxes in mesoscopic rings. They offer a method to relate the transition to the many-body localized phase to transport properties. In the delocalized regime, we find that the Drude weight distribution at a fixed disorder configuration agrees well with the random-matrix-theory prediction P (D ) ∝(γ2+D2) -3 /2 , although the distribution width γ strongly fluctuates between disorder realizations. A crossover is observed towards a distribution with different large-D asymptotics deep in the many-body localized phase, which however differs from the commonly expected Cauchy distribution. We show that the average distribution width <γ >, rescaled by L Δ ,Δ being the average level spacing in the middle of the spectrum and L the systems size, is an efficient probe of the many-body localization transition, as it increases (vanishes) exponentially in the delocalized (localized) phase.

Characterization of bonded stationary phase performance as a function of qualitative and quantitative chromatographic factors in chaotropic chromatography with risperidone and its impurities as model substances.

PubMed

Čolović, Jelena; Rmandić, Milena; Malenović, Anđelija

2018-05-17

Numerous stationary phases have been developed with the aim to provide desired performances during chromatographic analysis of the basic solutes in their protonated form. In this work, the procedure for the characterization of bonded stationary phase performance, when both qualitative and quantitative chromatographic factors were varied in chaotropic chromatography, was proposed. Risperidone and its three impurities were selected as model substances, while acetonitrile content in the mobile phase (20-30%), the pH of the aqueous phase (3.00-5.00), the content of chaotropic agents in the aqueous phase (10-100 mM), type of chaotropic agent (NaClO 4 , CF 3 COONa), and stationary phase type (Zorbax Eclipse XDB, Zorbax Extend) were studied as chromatographic factors. The proposed procedure implies the combination of D-optimal experimental design, indirect modeling, and polynomial-modified Gaussian model, while grid point search method was selected for the final choice of the experimental conditions which lead to the best possible stationary phase performance for basic solutes. Good agreement between experimentally obtained chromatogram and simulated chromatogram for chosen experimental conditions (25% acetonitrile, 75 mM of NaClO 4 , pH 4.00 on Zorbax Eclipse XDB column) confirmed the applicability of the proposed procedure. The additional point was selected for the verification of proposed procedure ability to distinguish changes in solutes' elution order. Simulated chromatogram for 21.5% acetonitrile, 85 mM of NaClO 4 , pH 5.00 on Zorbax Eclipse XDB column was in line with experimental data. Furthermore, the values of left and right peak half-widths obtained from indirect modeling were used in order to evaluate performances of differently modified stationary phases applying a half-width plots approach. The results from half-width plot approach as well as from the proposed procedure indicate higher efficiency and better separation performance of the stationary phase extra densely bonded and double end-capped with trimethylsilyl group than the stationary phase with the combination of end-capping and bidentate silane bonding for chromatographic analysis of basic solutes in RP-HPLC systems with chaotropic agents. Graphical abstract ᅟ.

Crustal thickness variations in the Zagros continental collision zone (Iran) from joint inversion of receiver functions and surface wave dispersion

NASA Astrophysics Data System (ADS)

Tatar, M.; Nasrabadi, A.

2013-10-01

Variations in crustal thickness in the Zagros determined by joint inversion of P wave receiver functions (RFs) and Rayleigh wave group and phase velocity dispersion. The time domain iterative deconvolution procedure was employed to compute RFs from teleseismic recordings at seven broadband stations of INSN network. Rayleigh wave phase velocity dispersion curves were estimated employing two-station method. Fundamental mode Rayleigh wave group velocities for each station is taken from a regional scale surface wave tomographic imaging. The main variations in crustal thickness that we observe are between stations located in the Zagros fold and thrust belt with those located in the Sanandaj-Sirjan zone (SSZ) and Urumieh-Dokhtar magmatic assemblage (UDMA). Our results indicate that the average crustal thickness beneath the Zagros Mountain Range varies from ˜46 km in Western and Central Zagros beneath SHGR and GHIR up to ˜50 km beneath BNDS located in easternmost of the Zagros. Toward NE, we observe an increase in Moho depth where it reaches ˜58 km beneath SNGE located in the SSZ. Average crustal thickness also varies beneath the UDMA from ˜50 km in western parts below ASAO to ˜58 in central parts below NASN. The observed variation along the SSZ and UDMA may be associated to ongoing slab steepening or break off in the NW Zagros, comparing under thrusting of the Arabian plate beneath Central Zagros. The results show that in Central Iran, the crustal thickness decrease again to ˜47 km below KRBR. There is not a significant crustal thickness difference along the Zagros fold and thrust belt. We found the same crystalline crust of ˜34 km thick beneath the different parts of the Zagros fold and thrust belt. The similarity of crustal structure suggests that the crust of the Zagros fold and thrust belt was uniform before subsidence and deposition of the sediments. Our results confirm that the shortening of the western and eastern parts of the Zagros basement is small and has only started recently.

ULF waves and radiation belts: earthward penetration of Pc 4-5 waves and energetic electron flux enhancements during geospace magnetic storms

NASA Astrophysics Data System (ADS)

Georgiou, Marina; Daglis, Ioannis; Zesta, Eftyhia; Balasis, George; Tsinganos, Kanaris

2013-04-01

Energetic particle fluxes in the outer radiation belt can vary over orders of magnitude on time scales ranging from minutes, to days and years. Geospace magnetic storms when sufficiently strong to exceed key thresholds of the Dst index may either increase or decrease the fluxes of energetic electrons. We examine the responses of energetic electrons to nine moderate, intense and weak magnetic storms, which occurred at different phases of the solar cycle, and compare these with concurrent variations of ULF wave power. Pc 4-5 waves with frequencies in the range of a few mHz may be generated internally in the magnetosphere by low frequency instabilities of ring current ions and externally by shear instabilities at the magnetopause flanks, or compressive variations in the solar wind. Here, we present multipoint observations from ground-based magnetometer arrays collocated with electron drift orbits, which are complemented and measurements by conjugate multi-point satellites, such as CHAMP, Cluster, GOES and THEMIS. We discuss the excitation, growth and decay characteristics of Pc 4-5 waves during the different phases of the magnetic storms with particular emphasis on the distribution of Pc 4-5 wave power over a variety of L shells. We investigate whether Pc 4-5 wave power penetrates to lower L shell values during periods of relatively intense geomagnetic activity as compared to weak magnetic storms. Structural changes of the magnetosphere during intense geomagnetic storms can play an important role in the generation and penetration of Pc 4-5 waves deep into the inner magnetosphere, which in turn is of significance for the wave-particle interactions contributing to the acceleration, transport and loss of electrons in the outer radiation belt. We present preliminary statistics of Pc 4-5 waves observed during magnetic storms of varying intensity, which occurred over the course of the previous solar cycle. This work is supported by the European Community's Seventh Framework Programme under grant agreement no. 284520 for the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project.

Intrusive rocks and plutonic belts of southeastern Alaska, U.S.A.

USGS Publications Warehouse

Brew, David A.; Morrell, Robert P.; Roddick, J.A.

1983-01-01

About 30 percent of the 175,000-km2 area of southeastern Alaska is underlain by intrusive igneous rocks. Compilation of available information on the distribution, composition, and ages of these rocks indicates the presence of six major and six minor plutonic belts. From west to east, the major belts are: the Fairweather-Baranof belt of early to mid-Tertiary granodiorite; the Muir-Chichagof belt of mid-Cretaceous tonalite and granodiorite; the Admiralty-Revillagigedo belt of porphyritic granodiorite, quartz diorite, and diorite of probable Cretaceous age; the Klukwan-Duke belt of concentrically zoned or Alaskan-type ultramafic-mafic plutons of mid-Cretaceous age within the Admiralty-Revillagigedo belt; the Coast Plutonic Complex sill belt of tonalite of unknown, but perhaps mid-Cretaceous, age; and the Coast Plutonic Complex belt I of early to mid-Tertiary granodiorite and quartz monzonite. The minor belts are distributed as follows: the Glacier Bay belt of Cretaceous and(or) Tertiary granodiorite, tonalite, and quartz diorite lies within the Fair-weather-Baranof belt; layered gabbro complexes of inferred mid-Tertiary age lie within and are probably related to the Fairweather-Baranof belt; the Chilkat-Chichagof belt of Jurassic granodiorite and tonalite lies within the Muir-Chichagof belt; the Sitkoh Bay alkaline, the Kendrick Bay pyroxenite to quartz monzonite, and the Annette and Cape Fox trondhjemite plutons, all interpreted to be of Ordovician(?) age, together form the crude southern southeastern Alaska belt within the Muir-Chichagof belt; the Kuiu-Etolin mid-Tertiary belt of volcanic and plutonic rocks extends from the Muir-Chichagof belt eastward into the Admiralty-Revillagigedo belt; and the Behm Canal belt of mid- to late Tertiary granite lies within and next to Coast Plutonic Complex belt II. In addition, scattered mafic-ultramafic bodies occur within the Fairweather-Baranof, Muir-Chichagof, and Coast Plutonic Complex belts I and II. Palinspastic reconstruction of 200 km of right-lateral movement on the Chatham Strait fault does not significantly change the pattern of the major belts but does bring parts of the minor mid-Tertiary and Ordovician(?) belts closer together. The major belts are related to the stratigraphic-tectonic terranes of Berg, Jones, and Coney (1978) as follows: the Fairweather-Baranof belt is largely in the Chugach, Wrangell (Wrangellia), and Alexander terranes; the Muir-Chichagof belt is in the Alexander and Wrangell terranes; the Admiralty-Revillagigedo belt is in the Gravina and Taku terranes; the Klukwan-Duke belt is in the Gravina, Taku, and Alexander terranes; the Coast Plutonic Complex sill belt is probably between the Taku and Tracy Arm terranes; and the Coast Plutonic Complex belts I and II are in the Tracy Arm and Stikine terranes. Significant metallic-mineral deposits are spatially related to certain of these belts, and some deposits may be genetically related. Gold, copper, and molybdenum occurrences may be related to granodiorites of the Fairweather-Baranof belt. Magmatic copper-nickel deposits occur in the layered gabbro within that belt. The Juneau gold belt, which contains gold, silver, copper, lead, and zinc occurrences, parallels and lies close to the Coast Plutonic Complex sill belt; iron deposits occur in the Klukwan-Duke belt; and porphyry molybdenum deposits occur in the Behm Canal belt. The Muir-Chichagof belt of mid-Cretaceous age and the Admiralty-Revillagigedo belt of probable Cretaceous age are currently interpreted as possible magmatic arcs associated with subduction events. In general, the other belts of intrusive rocks are spatially related to structural discontinuities, but genetic relations, if any, are not yet known. The Coast Plutonic Complex sill belt is probably related to a post-Triassic, pre-early Tertiary suture zone that nearly corresponds to the boundary between the Tracy Arm and Taku terranes. The boundary between the Admiralty-Revillagigedo and Muir-Chichagof belts coincides nearly with the Seymour Canal-Clarence Strait lineament and also is probably a major post-Triassic suture.

Effect of masking phase-only holograms on the quality of reconstructed images.

PubMed

Deng, Yuanbo; Chu, Daping

2016-04-20

A phase-only hologram modulates the phase of the incident light and diffracts it efficiently with low energy loss because of the minimum absorption. Much research attention has been focused on how to generate phase-only holograms, and little work has been done to understand the effect and limitation of their partial implementation, possibly due to physical defects and constraints, in particular as in the practical situations where a phase-only hologram is confined or needs to be sliced or tiled. The present study simulates the effect of masking phase-only holograms on the quality of reconstructed images in three different scenarios with different filling factors, filling positions, and illumination intensity profiles. Quantitative analysis confirms that the width of the image point spread function becomes wider and the image quality decreases, as expected, when the filling factor decreases, and the image quality remains the same for different filling positions as well. The width of the image point spread function as derived from different filling factors shows a consistent behavior to that as measured directly from the reconstructed image, especially as the filling factor becomes small. Finally, mask profiles of different shapes and intensity distributions are shown to have more complicated effects on the image point spread function, which in turn affects the quality and textures of the reconstructed image.

Deformational sequence of a portion of the Michipicoten greenstone belt, Chabanel Township, Ontario

NASA Technical Reports Server (NTRS)

Shrady, C. H.; Mcgill, G. E.

1986-01-01

Detailed mapping at a scale of one inch = 400 feet is being carried out within a fume kill, having excellent exposure, located in the southwestern portion of the Michipicoten Greenstone Belt near Wawa, Ontario. The rocks are metasediments and metavolcanics of lower greenschist facies. U-Pb geochronology indicates that they are at least 2698 + or - 11 Ma old. The lithologic packages strike northeast to northwest, but the dominant strike is approximately east-west. Sedimentary structures and graded bedding are well preserved, aiding in the structural interpretation of this multiply deformed area. At least six phases of deformation within a relatively small area of the Michipicoten Greenstone Belt have been tentatively identified. These include the following structural features in approximate order of occurrence: (0) soft-sediment structures; (1) regionally overturned rocks, flattened pebbles, bedding parallel cleavage, and early, approximately bedding parallel faults; (2) northwest to north striking cleavage; (3) northeast striking cleavage and associated folds, and at least some late movement on approximately bedding parallel faults; (4) north-northwest and northeast trending faults; and (5) diabase dikes and associated fracture cleavages. Minor displacement of the diabase dikes occurs on faults that appear to be reactivated older structures.

Determinants of patronage of traditional bone setters in the middle belt of Nigeria.

PubMed

Nwadiaro, H C; Ozoilo, K N; Nwadiaro, P O; Kidmas, A T; Oboiren, M

2008-01-01

Traditional bone setting is a practice that is common in our environment. This is a community based survey of opinions concerning orthodox and traditional fracture management in four states of the middle belt of Nigeria. We set out to ascertain the factors influencing preference of treatment of fractures among populations in the middle belt of Nigeria. A community based questionnaire survey of randomly selected adults regarding preference of choice of treatment between orthodox and traditional fracture management. One hundred and eighty-six questionnaires were found analyzable with a male to female ratio of 2:1. There was a preponderance of preference for orthodox fracture management (70.4%). Decisions were mainly collegiate, outside the influence of the individual; only 9.9% decided to attend traditional bone setters on their own. Reasons adduced for preference of traditional bone setters were incongruous and inconsistent. A fixated cultural outlook was recognized as being the motivating factor for patronage of traditional bone setters. Need for enlightenment campaign of the public against patronage of traditional bone setters is emphasized. A gradual phasing out of traditional bone setting with a road map towards making orthodox fracture management available to all is advocated.

Trace-element fingerprints of chromite, magnetite and sulfides from the 3.1 Ga ultramafic-mafic rocks of the Nuggihalli greenstone belt, Western Dharwar craton (India)

NASA Astrophysics Data System (ADS)

Mukherjee, Ria; Mondal, Sisir K.; González-Jiménez, José M.; Griffin, William L.; Pearson, Norman J.; O'Reilly, Suzanne Y.

2015-06-01

The 3.1 Ga Nuggihalli greenstone belt in the Western Dharwar craton is comprised of chromitite-bearing sill-like ultramafic-mafic rocks that are surrounded by metavolcanic schists (compositionally komatiitic to komatiitic basalts) and a suite of tonalite-trondhjemite-granodiorite gneissic rocks. The sill-like plutonic unit consists of a succession of serpentinite (after dunite)-peridotite-pyroxenite and gabbro with bands of titaniferous magnetite ore. The chromitite ore-bodies (length ≈30-500 m; width ≈2-15 m) are hosted by the serpentinite-peridotite unit. Unaltered chromites from massive chromitites (>80 % modal chromite) of the Byrapur and Bhaktarhalli chromite mines in the greenstone belt are characterized by high Cr# (100Cr/(Cr + Al)) of 78-86 and moderate Mg# (100 Mg/(Mg + Fe2+)) of 45-55. In situ trace-element analysis (LA-ICPMS) of unaltered chromites indicates that the parental magma of the chromitite ore-bodies was a komatiite lacking nickel-sulfide mineralization. In the Ga/Fe3+# versus Ti/Fe3+# diagram, the Byrapur chromites plot in the field of suprasubduction zone (SSZ) chromites while those from Bhaktarhalli lie in the MOR field. The above results corroborate our previous results based on major-element characteristics of the chromites, where the calculated parental melt of the Byrapur chromites was komatiitic to komatiitic basalt, and the Bhaktarhalli chromite was derived from Archean high-Mg basalt. The major-element chromite data hinted at the possibility of a SSZ environment existing in the Archean. Altered and compositionally zoned chromite grains in our study show a decrease in Ga, V, Co, Zn, Mn and enrichments of Ni and Ti in the ferritchromit rims. Trace-element heterogeneity in the altered chromites is attributed to serpentinization. The trace-element patterns of magnetite from the massive magnetite bands in the greenstone belt are similar to those from magmatic Fe-Ti-V-rich magnetite bands in layered intrusions, and magnetites from andesitic melts, suggesting that magnetite crystallized from an evolved gabbroic melt. Enrichments of Ni, Co, Te, As and Bi in disseminated millerite and niccolite occurring within chromitites, and in disseminated bravoite within magnetites, reflect element mobility during serpentinization. Monosulfide solid solution inclusions within pyroxenes (altered to actinolite) in pyroxenite, and interstitial pyrites and chalcopyrites in magnetite, retain primary characteristics except for Fe-enrichment in chalcopyrite, probably due to sub-solidus re-equilibration with magnetite. Disseminated sulfides are depleted in platinum-group elements (PGE) due to late sulfide saturation and the PGE-depleted nature of the mantle source of the sill-like ultramafic-mafic plutonic rocks in the Nuggihalli greenstone belt.

Formation and inversion of transtensional basins in the western part of the Lachlan Fold Belt, Australia, with emphasis on the Cobar Basin

NASA Astrophysics Data System (ADS)

Glen, R. A.

The Palaeozoic history of the western part of the Lachlan Fold Belt in New South Wales was dominated by strike-slip tectonics. In the latest Silurian to late Early Devonian, an area of crust >25,000 km 2 lying west of the Gilmore Suture underwent regional sinistral transtension, leading to the development of intracratonic successor basins, troughs and flanking shelves. The volcaniclastic deep-water Mount Hope Trough and Rast Trough, the siliciclastic Cobar Basin and the volcanic-rich Canbelego-Mineral Hill Belt of the Kopyje Shelf all were initiated around the Siluro-Devonian boundary. They all show clear evidence of having evolved by both active syn-rift processes and passive later post-rift (sag-phase) processes. Active syn-rift faulting is best documented for the Cobar Basin and Mount Hope Trough. In the former case, the synchronous activity on several fault sets suggests that the basin formed by sinistral transtension in response to a direction of maximum extension oriented NE-SW. Structures formed during inversion of the Cobar Basin and Canbelego-Mineral Hill Belt indicate closure under a dextral transpressive strain regime, with a far-field direction of maximum shortening oriented NE-SW. In the Cobar Basin, shortening was partitioned into two structural zones. A high-strain zone in the east was developed into a positive half-flower structure by re-activation of early faults and by formation of short-cut thrusts, some with strike-slip movement, above an inferred steep strike-slip fault. Intense subvertical cleavage, a steep extension lineation and variably plunging folds are also present. A lower-strain zone to the west developed by syn-depositional faults being activated as thrusts soling into a gently dipping detachment. A subvertical cleavage and steep extension lineation are locally present, and variably plunging folds are common. Whereas Siluro-Devonian basin-opening appeared to be synchronous in the western part of the fold belt, the different period of basin inversion in the Cobar region (late Early Devonian and Carboniferous) may reflect different movement histories on the master strike-slip faults in this part of the fold belt, the Gilmore Suture and Kiewa Fault.

Coordinative structuring of gait kinematics during adaptation to variable and asymmetric split-belt treadmill walking - A principal component analysis approach.

PubMed

Hinkel-Lipsker, Jacob W; Hahn, Michael E

2018-06-01

Gait adaptation is a task that requires fine-tuned coordination of all degrees of freedom in the lower limbs by the central nervous system. However, when individuals change their gait it is unknown how this coordination is organized, and how it can be influenced by contextual interference during practice. Such knowledge could provide information about measurement of gait adaptation during rehabilitation. Able-bodied individuals completed an acute bout of asymmetric split-belt treadmill walking, where one limb was driven at a constant velocity and the other according to one of three designed practice paradigms: serial practice, where the variable limb belt velocity increased over time; random blocked practice, where every 20 strides the variable limb belt velocity changed randomly; random practice, where every stride the variable limb belt velocity changed randomly. On the second day, subjects completed one of two different transfer tests; one with a belt asymmetry close to that experienced on the acquisition day (transfer 1; 1.5:1), and one with a greater asymmetry (transfer 2; 2:1) . To reduce this inherently high-dimensional dataset, principal component analyses were used for kinematic data collected throughout the acquisition and transfer phases; resulting in extraction of the first two principal components (PCs). For acquisition, PC1 and PC2 were related to sagittal and frontal plane control. For transfer 1, PC1 and PC2 were related to frontal plane control of the base of support and whole-body center of mass. For transfer 2, PC1 did not have any variables with high enough coefficients deemed to be relevant, and PC2 was related to sagittal plane control. Observations of principal component scores indicate that variance structuring differs among practice groups during acquisition and transfer 1, but not transfer 2. These results demonstrate the main kinematic coordinative structures that exist during gait adaptation, and that control of sagittal plane and frontal plane motion are perhaps a trade-off during acquisition of a novel asymmetric gait pattern. Copyright © 2018 Elsevier B.V. All rights reserved.

Observed use of automatic seat belts in 1987 cars.

PubMed

Williams, A F; Wells, J K; Lund, A K; Teed, N

1989-10-01

Usage of the automatic belt systems supplied by six large-volume automobile manufacturers to meet the federal requirements for automatic restraints were observed in suburban Washington, D.C., Chicago, Los Angeles, and Philadelphia. The different belt systems studied were: Ford and Toyota (motorized, nondetachable automatic shoulder belt), Nissan (motorized, detachable shoulder belt), VW and Chrysler (nonmotorized, detachable shoulder belt), and GM (nonmotorized detachable lap and shoulder belt). Use of automatic belts was significantly greater than manual belt use in otherwise comparable late-model cars for all manufacturers except Chrysler; in Chrysler cars, automatic belt use was significantly lower than manual belt use. The automatic shoulder belts provided by Ford, Nissan, Toyota, and VW increased use rates to about 90%. Because use rates were lower in Ford cars with manual belts, their increase was greater. GM cars had the smallest increase in use rates; however, lap belt use was highest in GM cars. The other manufacturers supply knee bolsters to supplement shoulder belt protection; all--except VW--also provide manual lap belts, which were used by about half of those who used the automatic shoulder belt. The results indicate that some manufacturers have been more successful than others in providing automatic belt systems that result in high use that, in turn, will mean fewer deaths and injuries in those cars.

Drainage basin and topographic analysis of a tropical landscape: Insights into surface and tectonic processes in northern Borneo

NASA Astrophysics Data System (ADS)

Mathew, Manoj Joseph; Menier, David; Siddiqui, Numair; Ramkumar, Mu.; Santosh, M.; Kumar, Shashi; Hassaan, Muhammad

2016-07-01

We investigated the recent landscape development of Borneo through geomorphic analysis of two large drainage basins (Rajang and Baram basins). The extraction of morphometric parameters utilizing digital terrain data in a GIS environment, focusing on hydrography (stream length-gradient index, ratio of valley floor width to valley height, and transverse topographic symmetry factor) and topography (local relief and relief anomaly), was carried out in order to elucidate processes governing drainage and landscape evolution. Anomalously high and low values of stream length-gradient indices of main tributary streams associated with faults and multiple knick-points along the channel profiles are linked to deformation events. The development of deeply incised V-shaped valleys show enhanced incision capability of streams in response to steepening of hillslope gradients following tectonic inputs. Deflection of streams and probable dynamic reorganization of the drainage system through stream capture processes as feedbacks to tectonic uplift and orographic effect are observed. Local relief and relief anomaly maps highlight the presence of preserved elevation-accordant relict portions of landscapes characterized by low amplitude relief, nested between ridgelines in regions of complex folding. Our results reveal dynamic geomorphic adjustment of the landscape due to perturbations in tectonic and climatic boundary conditions. The implication is that the landscape of north Borneo experienced a tectonic phase of rapid uplift after 5 Ma and undergoes active folding of the Rajang Group thrust belts in the present-day. Active shortening combined with high rates of denudation in Sarawak, demonstrates transience emphasized by the drainage system attempting to adjust to tectonic and climatic forcing.

Lightcurve and Rotational Period Determination for 5813 Eizaburo and (11745) 1999 NH3

NASA Astrophysics Data System (ADS)

Salvaggio, Fabio; Banfi, Massimo; Marchini, Alessandro; Papini, Riccardo

2018-01-01

Photometric observations of the main-belt asteroids 5813 Eizaburo and (11745) 1999 NH3 performed made in 2017 August revealed a bimodal lightcurve phased to 2.876 ± 0.002 h for 5813 Eizaburo and 3.280 ± 0.001 h for (11745) 1999 NH3 as the most likely synodic rotational periods for these asteroids.

Dynamics of the Trapped Electron Phase Space Density in Relation to the Wave Activity in the Inner Magnetosphere

NASA Astrophysics Data System (ADS)

Vassiliadis, D.; Green, J.

2008-05-01

The phase space density fe of the radiation belt electron population is reconstructed based on measurements made by POLAR/HIST. The density peaks in invariant space (mu, K, L*) are shown to be responding to changes in the solar wind velocity and density, and the interplanetary magnetic field. We have associated specific types of storms with the appearance of peaks thereby producing a climatology of fe. We will report on comparing the phase space density changes during these storms to the ULF wave power in the inner magnetosphere remote- sensed by the IMAGE magnetometer array and related properties of the wave environment.

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

Extracting respiratory information from seismocardiogram signals acquired on the chest using a miniature accelerometer.

PubMed

Pandia, Keya; Inan, Omer T; Kovacs, Gregory T A; Giovangrandi, Laurent

2012-10-01

Seismocardiography (SCG) is a non-invasive measurement of the vibrations of the chest caused by the heartbeat. SCG signals can be measured using a miniature accelerometer attached to the chest, and are thus well-suited for unobtrusive and long-term patient monitoring. Additionally, SCG contains information relating to both cardiovascular and respiratory systems. In this work, algorithms were developed for extracting three respiration-dependent features of the SCG signal: intensity modulation, timing interval changes within each heartbeat, and timing interval changes between successive heartbeats. Simultaneously with a reference respiration belt, SCG signals were measured from 20 healthy subjects and a respiration rate was estimated using each of the three SCG features and the reference signal. The agreement between each of the three accelerometer-derived respiration rate measurements was computed with respect to the respiration rate derived from the reference respiration belt. The respiration rate obtained from the intensity modulation in the SCG signal was found to be in closest agreement with the respiration rate obtained from the reference respiration belt: the bias was found to be 0.06 breaths per minute with a 95% confidence interval of -0.99 to 1.11 breaths per minute. The limits of agreement between the respiration rates estimated using SCG (intensity modulation) and the reference were within the clinically relevant ranges given in existing literature, demonstrating that SCG could be used for both cardiovascular and respiratory monitoring. Furthermore, phases of each of the three SCG parameters were investigated at four instances of a respiration cycle-start inspiration, peak inspiration, start expiration, and peak expiration-and during breath hold (apnea). The phases of the three SCG parameters observed during the respiration cycle were congruent with existing literature and physiologically expected trends.

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

A waveguide finite element aided analysis of the wave field on a stationary tyre, not in contact with the ground

NASA Astrophysics Data System (ADS)

Sabiniarz, Patrick; Kropp, Wolfgang

2010-07-01

Although tyre/road noise has been a research subject for more than three decades, there is still no consensus in the literature as to which waves on a tyre are mainly responsible for the radiation of sound during rolling. Even the free vibrational behaviour of a stationary (non-rotating) tyre, not in contact with the ground, is still not well understood in the mid- and high-frequency ranges. Thus, gaining an improved understanding of this behaviour is a natural first step towards illuminating the question of which waves on a rolling tyre contribute to sound radiation. This is the topic of the present paper, in which a model based on the waveguide finite element method (WFEM) is used to study free wave propagation, on a stationary tyre, in the range 0-1500 Hz. In the low-frequency region (0-300 Hz), wave propagation is found to be rather straightforward, with two main wave-types present. Both have cross-section modes involving a nearly rigid motion of the belt. For higher frequencies (300-1500 Hz) the behaviour is more complex, including phenomena such as 'curve veering' and waves for which the phase speed and group speed have opposite signs. Wave-types identified in this region include (i) waves involving mainly sidewall deformation, (ii) belt bending waves, (iii) a wave with significant extensional deformation of the central belt region and (iv) a wave with a 'breathing' cross-section mode. The phase speed corresponding to found waves is computed and their radiation efficiency is discussed, assuming free-field conditions. In a future publication, the tyre model will be used in conjunction with a contact model and a radiation model to investigate the contribution of these waves to radiated sound during rolling.

A frequency-based window width optimized two-dimensional S-Transform profilometry

NASA Astrophysics Data System (ADS)

Zhong, Min; Chen, Feng; Xiao, Chao

2017-11-01

A new scheme is proposed to as a frequency-based window width optimized two-dimensional S-Transform profilometry, in which parameters pu and pv are introduced to control the width of a two-dimensional Gaussian window. Unlike the standard two-dimensional S-transform using the Gaussian window with window width proportional to the reciprocal local frequency of the tested signal, the size of window width for the optimized two-dimensional S-Transform varies with the pu th (pv th) power of the reciprocal local frequency fx (fy) in x (y) direction. The paper gives a detailed theoretical analysis of optimized two-dimensional S-Transform in fringe analysis as well as the characteristics of the modified Gauss window. Simulations are applied to evaluate the proposed scheme, the results show that the new scheme has better noise reduction ability and can extract phase distribution more precise in comparison with the standard two-dimensional S-transform even though the surface of the measured object varies sharply. Finally, the proposed scheme is demonstrated on three-dimensional surface reconstruction for a complex plastic cat mask to show its effectiveness.

Quantum coherence in the reflection of above barrier wavepackets

NASA Astrophysics Data System (ADS)

Petersen, Jakob; Pollak, Eli

2018-02-01

The quantum phenomenon of above barrier reflection is investigated from a time-dependent perspective using Gaussian wavepackets. The transition path time distribution, which in principle is experimentally measurable, is used to study the mean flight times ⟨t⟩R and ⟨t⟩T associated with the reflection and the transmission over the barrier paying special attention to their dependence on the width of the barrier. Both flight times, and their difference Δt, exhibit two distinct regimes depending on the ratio of the spatial width of the incident wavepacket and the length of the barrier. When the ratio is larger than unity, the reflection and transmission dynamics are coherent and dominated by the resonances above the barrier. The flight times ⟨t⟩R/T and the flight time difference Δt oscillate as a function of the barrier width (almost in phase with the transmission probability). These oscillations reflect a momentum filtering effect related to the coherent superposition of the reflected and transmitted waves. For a ratio less than unity, the barrier reflection and transmission dynamics are incoherent and the oscillations are absent. The barrier width which separates the coherent and incoherent regimes is identified analytically. The oscillatory structure of the time difference Δt as a function of the barrier width in the coherent regime is absent when considered in terms of the Wigner phase time delays for reflection and transmission. We conclude that the Wigner phase time does not correctly describe the temporal properties of above barrier reflection. We also find that the structure of the reflected and transmitted wavepackets depends on the coherence of the process. In the coherent regime, the wavepackets can have an overlapping peak structure, but the peaks are not fully resolved. In the incoherent regime, the wavepackets split in time into distinct separated Gaussian like waves, each one reflecting the number of times the wavepacket crosses the barrier region before exiting. A classical Wigner approximation, using classical trajectories which upon reaching an edge of the barrier are reflected or transmitted as if the edge was a step potential, is quantitative in the incoherent regime. The implications of the coherence observed on resonance reactive scattering are discussed.

Ternary isocratic mobile phase optimization utilizing resolution Design Space based on retention time and peak width modeling.

PubMed

Kawabe, Takefumi; Tomitsuka, Toshiaki; Kajiro, Toshi; Kishi, Naoyuki; Toyo'oka, Toshimasa

2013-01-18

An optimization procedure of ternary isocratic mobile phase composition in the HPLC method using a statistical prediction model and visualization technique is described. In this report, two prediction models were first evaluated to obtain reliable prediction results. The retention time prediction model was constructed by modification from past respectable knowledge of retention modeling against ternary solvent strength changes. An excellent correlation between observed and predicted retention time was given in various kinds of pharmaceutical compounds by the multiple regression modeling of solvent strength parameters. The peak width of half height prediction model employed polynomial fitting of the retention time, because a linear relationship between the peak width of half height and the retention time was not obtained even after taking into account the contribution of the extra-column effect based on a moment method. Accurate prediction results were able to be obtained by such model, showing mostly over 0.99 value of correlation coefficient between observed and predicted peak width of half height. Then, a procedure to visualize a resolution Design Space was tried as the secondary challenge. An artificial neural network method was performed to link directly between ternary solvent strength parameters and predicted resolution, which were determined by accurate prediction results of retention time and a peak width of half height, and to visualize appropriate ternary mobile phase compositions as a range of resolution over 1.5 on the contour profile. By using mixtures of similar pharmaceutical compounds in case studies, we verified a possibility of prediction to find the optimal range of condition. Observed chromatographic results on the optimal condition mostly matched with the prediction and the average of difference between observed and predicted resolution were approximately 0.3. This means that enough accuracy for prediction could be achieved by the proposed procedure. Consequently, the procedure to search the optimal range of ternary solvent strength achieving an appropriate separation is provided by using the resolution Design Space based on accurate prediction. Copyright © 2012 Elsevier B.V. All rights reserved.

Confinement-induced liquid ordering investigated by x-ray phase retrieval

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

Bunk, Oliver; Diaz, Ana; Pfeiffer, Franz

2007-02-15

Using synchrotron x-ray diffraction, we have determined the ensemble-averaged density profile of colloidal fluids within confining channels of different widths. We observe an oscillatory ordering-disordering behavior of the colloidal particles as a function of the channel width, while the colloidal solution remains in the liquid state. This phenomenon has been suggested by surface force studies of hard-sphere fluids and also theoretically predicted, but here we see it by direct measurements of the structure for comparable systems.

Tight focusing properties of the azimuthal discrete phase modulated radially polarized LG11* beam

NASA Astrophysics Data System (ADS)

Zhao, Jiang; Li, Bo; Zhao, Heng; Hu, Yi; Wang, Wenjin; Wang, Youqing

2013-06-01

An novel method for generating an annual periodic optical chain by tight focusing the rotational symmetric π/0 phase plate modulated first order radially polarized Laguerre Gaussian (LG11*) beam with a high-NA lens is proposed. The optical chain is composed of either bright spots or dark spots. Vector diffraction numerical calculation method is employed to analyze the tight focus properties. The analyses indicate that the properties of the optical chains are closely related to the number of phase plate sectors, beam width of radially polarized LG11* beam and the numerical aperture of focusing lens. Furthermore, the average Full Width at Half Maximum (FWHM) of hollow dark spots or bright spots in optical chain is breaking the diffraction limit. These kinds of annular optical chains are expected to be applied in trapping or arranging multiple bar-like micro particles whose refractive index are either higher or lower than that of the ambient.

Laterally bendable belt conveyor

DOEpatents

Peterson, William J.

1985-01-01

An endless, laterally flexible and bendable belt conveyor particularly adapted for coal mining applications in facilitating the transport of the extracted coal up- or downslope and around corners in a continuous manner is disclosed. The conveying means includes a flat rubber belt reinforced along the middle portion thereof along which the major portion of the belt tension is directed so as to cause rotation of the tubular shaped belt when trammed around lateral turns thus preventing excessive belt bulging distortion between adjacent belt supports which would inhibit belt transport. Pretension induced into the fabric reinforced flat rubber belt by conventional belt take-up means supports the load conveyed when the belt conveyor is making lateral turns. The carrying and return portions of the belt are supported and formed into a tubular shape by a plurality of shapers positioned along its length. Each shaper is supported from above by a monorail and includes clusters of idler rollers which support the belt. Additional cluster rollers in each shaper permit the belt supporting roller clusters to rotate in response to the belt's operating tension imposed upon the cluster rollers by induced lateral belt friction forces. The freely rotating roller clusters thus permit the belt to twist on lateral curves without damage to itself while precluding escape of the conveyed material by effectively enclosing it in the tube-shaped, inner belt transport length.

Tectonomorphic evolution of the Eastern Cordillera fold-thrust belt, Colombia: New insights based on apatite and zircon (U-Th)/He thermochronometers

NASA Astrophysics Data System (ADS)

Ghorbal, B.; Stockli, D. F.; Mora, A.; Horton, B. K.; Blanco, V.; Sanchez, N.

2010-12-01

The Eastern Cordillera (EC) of Colombia marks the eastern boundary of Cenozoic fold-thrust deformation in the northern Andes. It is a classic example of an inversion belt formed in the retro-arc region, in this case superimposed on a Triassic/Jurassic to Cretaceous intracontinental rift system of northern South America. Ongoing thrust reactivation (inversion) in this contractional orogen provides an excellent opportunity to study the patterns of deformation and influence of preexisting anisotropies (Mora et al., 2006). The objective of this detailed (U-Th)/He study is to unravel the tectonic and thermal evolution of the EC from the Magdalena Valley basin in the west to the Llanos foreland basin in the east and reconstruct the temporal and spatial progression of deformation in the EC fold-thrust belt. Furthermore, the Subandean or foothills zone of Colombia is key for understanding the petroleum systems in the complex frontal zone of the inverted fold-thrust belt. We present detailed apatite and zircon (U-Th)/He thermochronometric data from surface samples along a ~220 km WNW-ESE transect across the EC from the frontal fold-thrust belt at the edge of the Llanos basin to the western edge of the EC, the Magdalena basin. Surface and borehole zircon and apatite (U-Th)/He data, integrated with structural data, show that the EC fold-thrust belt propagated foreland-ward from the axial zone to the modern edges of the fold-thrust belt from at least the early Oligocene to the early Miocene. Detailed apatite and zircon (U-Th)/He data from surface samples and borehole samples in the foothills-Llanos transition zone and the Middle Magdalena Valley basin, between the large-displacement Guaicaramo and Pajarito-Chámeza thrusts in the east and the La Salina fault system in the west show a temporally complex evolution. The frontal fold-thrust belt was characterized by continued progressive foreland-ward migration of deformation and an apparent phase of major out-of-sequence motion along both sides of the orogen in the latest Miocene to early Pliocene, with recent to active deformation again concentrated along the frontal-most faults of the EC. These detailed new apatite and zircon (U-Th)/He thermochronometric data elucidate the progressive deformation, thermal history, and along-long strike variation (Mora et al., 2010) of the fold-thrust belt in the EC of Colombia and provide important new insights into the complex interplay between hydrocarbon maturation and temporal and kinematic evolution of the frontal fold-thrust belt. References [1] Mora, A., M. Parra, M. R. Strecker, A. Kammer, C. Dimaté, and F. Rodriguez, 2006, Cenozoic contractional reactivation of Mesozoic extensional structures in the Eastern Cordillera of Colombia: Tectonics, v. 25, TC2010. [2] Mora, A., Horton, B.K., Mesa, A., Rubiano, J., Ketcham, R.A., Parra, M., Blanco, V., Garcia, D. and D.F. Stockli, 2010, Cenozoic deformation patterns in the Eastern Cordillera, Colombia: Inferences from fission track results and structural relationships. AAPG Bulletin, in press.

The late Archean Schreiber Hemlo and White River Dayohessarah greenstone belts, Superior Province: collages of oceanic plateaus, oceanic arcs, and subduction accretion complexes

NASA Astrophysics Data System (ADS)

Polat, A.; Kerrich, R.; Wyman, D. A.

1998-04-01

The late Archean (ca. 2.80-2.68 Ga) Schreiber-Hemlo and White River-Dayohessarah greenstone belts of the Superior Province, Canada, are supracrustal lithotectonic assemblages of ultramafic to tholeiitic basalt ocean plateau sequences, and tholeiitic to calc-alkaline volcanic arc sequences, and siliciclastic turbidites, collectively intruded by arc granitoids. The belts have undergone three major phases of deformation; two probably prior to, and one during the assembly of the southern Superior Province. Imbricated lithotectonic assemblages are often disrupted by syn-accretion strike-slip faults, suggesting that strike-slip faulting was an important aspect of greenstone belt evolution. Field relations, structural characteristics, and high-precision ICP-MS trace-element data obtained for representative lithologies of the Schreiber-Hemlo and White River-Dayohessarah greenstone belts suggest that they represent collages of oceanic plateaus, juvenile oceanic island arcs, in subduction-accretion complexes. Stratigraphic relationships, structural, and geochemical data from these Archean greenstone belts are consistent with a geodynamic evolution commencing with the initiation of a subduction zone at the margins of an oceanic plateau, similar to the modern Caribbean oceanic plateau and surrounding subduction-accretion complexes. All supracrustal assemblages include both ocean plateau and island-arc geochemical characteristics. The structural and geochemical characteristics of vertically and laterally dismembered supracrustal units of the Schreiber-Hemlo and White River-Dayohessarah greenstone belts cannot be explained either by a simple tectonic juxtaposition of lithotectonic assemblages with stratified volcanic and sedimentary units, or cyclic mafic to felsic bimodal volcanism models. A combination of out-of-sequence thrusting, and orogen-parallel strike-slip faulting of accreted ocean plateaus, oceanic arcs, and trench turbidites can account for the geological and geochemical characteristics of these greenstone belts. Following accretion, all supracrustal assemblages were multiply intruded by syn- to post-tectonic high-Al, and high-La/Yb n slab-derived trondhjemite-tonalite-granodiorite (TTG) plutons. The amalgamation processes of these lithotectonic assemblages are comparable to those of Phanerozoic subduction-accretion complexes, such as the Circum-Pacific, the western North American Cordilleran, and the Altaid orogenic belts, suggesting that subduction-accretion processes significantly contributed to the growth of the continental crust in the late Archean. The absence of blueschist and eclogite facies metamorphic rocks in Archean subduction-accretion complexes may be attributed to elevated thermal gradients and shallow-angle subduction. The melting of a hotter Archean mantle at ridges and in plumes would generate relatively small, hot, and hence shallowly subducting oceanic plates, promoting high-temperature metamorphism, migmatization, and slab melting. Larger, colder, Phanerozoic plates typically subduct at a steeper angle, generating high-pressure low-temperature conditions for blueschists and eclogites in the subduction zones, and low-La/Yb n granitoids from slab dehydration, and wedge melting. Metasedimentary subprovinces in the Superior Province, such as the Quetico and English River Subprovinces, have formerly been interpreted as accretionary complexes, outboard of the greenstone belt magmatic arcs. Here the greenstone-granitoid subprovinces are interpreted as collages of subduction-accretion complexes, island arcs and oceanic plateaus amalgamated at convergent plate margins, and the neighbouring metasedimentary subprovinces as foreland basins.

Granulite belts of Central India with special reference to the Bhopalpatnam Granulite Belt: Significance in crustal evolution and implications for Columbia supercontinent

NASA Astrophysics Data System (ADS)

Vansutre, Sandeep; Hari, K. R.

2010-11-01

The Central Indian collage incorporates the following major granulite belts: (1) the Balaghat-Bhandara Granulite Belt (BBG), (2) the Ramakona-Katangi Granulite Belt (RKG), (3) the Chhatuabhavna Granulite (CBG) of Bilaspur-Raigarh Belt, (4) the Makrohar Granulite Belt (MGB) of Mahakoshal supracrustals, (5) the Kondagaon Granulite Belt (KGGB), (6) the Bhopalpatnam Granulite Belt (BGB), (7) the Konta Granulite Belt (KTGB) and (8) the Karimnagar Granulite Belt (KNGB) of the East Dharwar Craton (EDC). We briefly synthesize the general geologic, petrologic and geochronologic features of these belts and explain the Precambrian crustal evolution in Central India. On the basis of the available data, a collisional relationship between Bastar craton and the EDC during the Paleo-Mesoproterozoic is reiterated as proposed by the earlier workers. The tectonic evolution of only few of the orogenic belts (BGB in particular) of Central India is related to Columbia.

Over 10-watt pico-second diffraction-limited output from a Nd:YVO4 slab amplifier with a phase conjugate mirror.

PubMed

Ojima, Yasukuni; Nawata, Kouji; Omatsu, Takashige

2005-10-31

We have produced a high beam quality pico-second laser based on a continuous-wave diode pumped Nd:YVO4 slab amplifier with a photorefractive phase conjugate mirror. 12.8W diffraction-limited output with a pulse width of 8.7ps was obtained.

Sink to survive: The persistence of ancient mountain belts through crustal density changes

NASA Astrophysics Data System (ADS)

Blackburn, T. J.; Ferrier, K.; Perron, J.

2012-12-01

Mountain belts form when collisions between continents thicken the Earth's crust, which buoyantly rises to remain in isostatic equilibrium with the underlying asthenosphere. Just as isostasy leads to the birth of mountain belts, it contributes to their destruction by responding to erosion with rock uplift, which in turn promotes further erosion. If the continental crust consisted of a single layer of constant density, erosion and isostatic rebound would continue thinning the crust until it was completely eroded. Such total destruction evidently does not happen, however, as the roots of Earth's oldest mountains have persisted for billions of years. One explanation for this preservation is that an orogen's isostatic response to erosion decreases over time as the crust increases in density as the lower crust undergoes metamorphic phase changes that accompany lithosphere cooling. The implication of this hypothesis is that erosion rates in mountain belts are linked to the thermal and density evolution of the lithosphere. We test this hypothesis with a global compilation of exhumation rates and erosion rates determined from published apatite fission track and cosmogenic 10Be measurements in collisional orogens ranging in formation age from 0 to 2 billion years. We compare these data to a numerical model of the thermal, density and erosional evolution of a decaying mountain belt. Measured and modeled data indicate that erosion is fastest in young, hot, low-density, and topographically high mountain belts, and that erosion rates decrease dramatically after 200-300 million years (My). This 200-300 My timescale is consistent with titanite U-Pb thermochronologic data from lower crustal xenoliths, which record cooling to temperatures consistent with garnet growth and crustal densification (~650 °C) within 200-300 My after orogenesis. For the same orogens, Sm-Nd and/or Lu-Hf garnet-whole rock isochron dates constrains lower crustal garnet growth and a corresponding crustal density increase to 200-450 My following orogenesis. Thus, geochronologic data at various timescales, from ancient thermal histories to geologically recent erosion rates, are consistent with an isostatic model that links the erosional decay of a collisional orogens to its thermal and density evolution. Given the geologic and climatic diversity of mountain ranges around the world, it is striking that their erosional histories are generally consistent with a single simple model. The scenario described here, in which young, hot, low-density orogens erode quickly for a few hundred My while older, colder, denser orogens erode much more slowly for billions of years provides an explanation for the persistence of some of Earth's oldest mountain belts. The importance of this erosional succession is underscored by the fact that continental landmasses are constructed through mountain building processes: like jigsaw puzzles with many pieces, continents are amalgamations of ancient mountain belts assembled over geologic time. Temperature-dependent densities appear to play a global role in the long-term evolution of mountain belts and continents, influencing the preservation of continental lithosphere over billions of years.

Long-term morphological evolution of a morphologically active man-made stream in the Netherlands

NASA Astrophysics Data System (ADS)

Eekhout, J.; Hoitink, T.

2010-12-01

Around 1770, a straight artificial canal (Gelderns-Nierskanaal) has been constructed between the River Niers and the River Meuse, crossing the border between Germany and the Netherlands, with the purpose of reducing flood risk in the downstream reaches of the River Niers. Whereas the German part of the canal is kept straight throughout time, the Dutch part was left unprotected and developed into a morphodynamically active stream featuring a meandering planform. The current planform and in-channel morphology are analyzed using airborne LiDAR data and historical topographic maps. Around the turn of the 18th century, the first attempts were made to make detailed topographic maps. From this time on, at least 16 topographic maps of the area around the stream were made. With the use of these historical topographic maps, a reconstruction is made of the planimetric shape of the stream over a period of 240 years. The LiDAR data show old meander belts at several places around the stream. Those belts compare well with the topographic maps. The sinuosity increases from upstream to downstream. This could be a consequence of the valley slope, where the upper part is flat and the slope increases in downstream direction. Besides, the LiDAR data show that erosion resulted in an incised valley, with dimensions to 50 m in width and 6 m in depth. Both the datasets are combined to make an estimate of the historical sediment budget of the stream.

Variation in the Water and Ammonia Abundance in Jupiter’s North Equatorial Belt

NASA Astrophysics Data System (ADS)

Bjoraker, Gordon L.; de Pater, Imke; Wong, Michael H.; Adamkovics, Mate; Hewagama, Tilak; Orton, Glenn

2017-10-01

We used iSHELL on NASA’s Infrared Telescope Facility and NIRSPEC on the Keck telescope concurrent with Juno perijoves 4-6 between February and May 2017 to obtain 5-micron spectra of Jupiter. Here we will focus on observations of the North Equatorial Belt. Spectrally resolved line profiles of CH3D, NH3, and H2O probe the 1 to 8-bar level of Jupiter’s troposphere. This overlaps with the weighting functions for several channels of Juno’s microwave radiometer. The profile of the CH3D lines at 4.66 microns is very broad in Hot Spots due to collisions with up to 8 bars of H2, where unit optical depth occurs due to collision-induced H2 opacity. The extreme width of these CH3D features implies that the Hot Spots that we observed do not have significant cloud opacity for P > 2 bars. We will discuss the abundance of NH3 and gaseous H2O within Hot Spots and other regions near the longitude of perijove for each Juno encounter. We had dry nights on Mauna Kea and a sufficient Doppler shift to detect H2O. We will compare line wings to derive H2O profiles in the 2 to 6-bar region. NEB Hot Spots are depleted in NH3 with respect to adjacent regions, especially for P < 2 bars. NEB Hot Spots are highly depleted in H2O for P < 5 bars.

ALMA observations of the narrow HR 4796A debris ring

NASA Astrophysics Data System (ADS)

Kennedy, Grant M.; Marino, Sebastian; Matrà, Luca; Panić, Olja; Wilner, David; Wyatt, Mark C.; Yelverton, Ben

2018-04-01

The young A0V star HR 4796A is host to a bright and narrow ring of dust, thought to originate in collisions between planetesimals within a belt analogous to the Solar system's Edgeworth-Kuiper belt. Here we present high spatial resolution 880 μm continuum images from the Atacama Large Millimeter Array. The 80 au radius dust ring is resolved radially with a characteristic width of 10 au, consistent with the narrow profile seen in scattered light. Our modelling consistently finds that the disc is also vertically resolved with a similar extent. However, this extent is less than the beam size, and a disc that is dynamically very cold (i.e. vertically thin) provides a better theoretical explanation for the narrow scattered light profile, so we remain cautious about this conclusion. We do not detect 12CO J=3-2 emission, concluding that unless the disc is dynamically cold the CO+CO2 ice content of the planetesimals is of order a few per cent or less. We consider the range of semi-major axes and masses of an interior planet supposed to cause the ring's eccentricity, finding that such a planet should be more massive than Neptune and orbit beyond 40 au. Independent of our ALMA observations, we note a conflict between mid-IR pericentre-glow and scattered light imaging interpretations, concluding that models where the spatial dust density and grain size vary around the ring should be explored.

Water and Ammonia Abundances in Jupiter's South Equatorial Belt and Equatorial Zone at the time of Juno Perijoves 4 to 6

NASA Astrophysics Data System (ADS)

Bjoraker, G. L.; De Pater, I.; Wong, M. H.; Adamkovics, M.; Hewagama, T.; Orton, G.

2017-12-01

We used iSHELL on NASA's Infrared Telescope Facility and NIRSPEC on the Keck telescope concurrent with Juno perijoves 4-6 between February and May 2017 to obtain 5-micron spectra of Jupiter. Here we will focus on observations of the South Equatorial Belt and the Equatorial Zone. Spectrally resolved line profiles of CH3D, NH3, and H2O probe the 1 to 8-bar level of Jupiter's troposphere. This overlaps with the weighting functions for several channels of Juno's microwave radiometer. The profile of the CH3D lines at 4.66 microns is very broad in SEB Hot Spots due to collisions with up to 8 bars of H2, where unit optical depth occurs due to collision-induced H2 opacity. The extreme width of these CH3D features implies that the Hot Spots that we observed do not have significant cloud opacity for P > 2 bars. We will discuss the abundance of NH3 and gaseous H2O within SEB Hot Spots and other regions near the longitude of perijove for each Juno encounter. We had dry nights on Mauna Kea and a sufficient Doppler shift to detect H2O. We will compare line wings to derive H2O profiles in the 2 to 6-bar region. SEB Hot Spots are highly depleted in H2O for P < 5 bars with respect to zones.

Two-phase model for prediction of cell-free layer width in blood flow

PubMed Central

Namgung, Bumseok; Ju, Meongkeun; Cabrales, Pedro; Kim, Sangho

2014-01-01

This study aimed to develop a numerical model capable of predicting changes in the cell-free layer (CFL) width in narrow tubes with consideration of red blood cell aggregation effects. The model development integrates to empirical relations for relative viscosity (ratio of apparent viscosity to medium viscosity) and core viscosity measured on independent blood samples to create a continuum model that includes these two regions. The constitutive relations were derived from in vitro experiments performed with three different glass-capillary tubes (inner diameter = 30, 50 and 100 μm) over a wide range of pseudoshear rates (5-300 s−1). The aggregation tendency of the blood samples was also varied by adding Dextran 500 kDa. Our model predicted that the CFL width was strongly modulated by the relative viscosity function. Aggregation increased the width of CFL, and this effect became more pronounced at low shear rates. The CFL widths predicted in the present study at high shear conditions were in agreement with those reported in previous studies. However, unlike previous multi-particle models, our model did not require a high computing cost, and it was capable of reproducing results for a thicker CFL width at low shear conditions, depending on aggregating tendency of the blood. PMID:23116701

Fiscal year 1981 US corn and soybeans pilot preliminary experiment plan, phase 1

NASA Technical Reports Server (NTRS)

Livingston, G. P.; Nedelman, K. S.; Norwood, D. F.; Smith, J. H. (Principal Investigator)

1981-01-01

A draft of the preliminary experiment plan for the foreign commodity production forecasting project fiscal year 1981 is presented. This draft plan includes: definition of the phase 1 and 2 U.S. pilot objectives; the proposed experiment design to evaluate crop calendar, area estimation, and area aggregation components for corn and soybean technologies using 1978/1979 crop-year data; a description of individual sensitivity evaluations of the baseline corn and soybean segment classification procedure; and technology and data assessment in support of the corn and soybean estimation technology for use in the U.S. central corn belt.

30 CFR 75.1731 - Maintenance of belt conveyors and belt conveyor entries.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maintenance of belt conveyors and belt conveyor....1731 Maintenance of belt conveyors and belt conveyor entries. (a) Damaged rollers, or other damaged belt conveyor components, which pose a fire hazard must be immediately repaired or replaced. All other...

Lunar phase function at 1064 nm from Lunar Orbiter Laser Altimeter passive and active radiometry

NASA Astrophysics Data System (ADS)

Barker, M. K.; Sun, X.; Mazarico, E.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.

2016-07-01

We present initial calibration and results of passive radiometry collected by the Lunar Orbiter Laser Altimeter onboard the Lunar Reconnaissance Orbiter over the course of 12 months. After correcting for time- and temperature-dependent dark noise and detector responsivity variations, the LOLA passive radiometry measurements are brought onto the absolute radiance scale of the SELENE Spectral Profiler. The resulting photometric precision is estimated to be ∼5%. We leverage the unique ability of LOLA to measure normal albedo to explore the 1064 nm phase function's dependence on various geologic parameters. On a global scale, we find that iron abundance and optical maturity (quantified by FeO and OMAT) are the dominant controlling parameters. Titanium abundance (TiO2), surface roughness on decimeter to decameter scales, and soil thermophysical properties have a smaller effect, but the latter two are correlated with OMAT, indicating that exposure age is the driving force behind their effects in a globally-averaged sense. The phase function also exhibits a dependence on surface slope at ∼300 m baselines, possibly the result of mass wasting exposing immature material and/or less space weathering due to reduced sky visibility. Modeling the photometric function in the Hapke framework, we find that, relative to the highlands, the maria exhibit decreased backscattering, a smaller opposition effect (OE) width, and a smaller OE amplitude. Immature highlands regolith has a higher backscattering fraction and a larger OE width compared to mature highlands regolith. Within the maria, the backscattering fraction and OE width show little dependence on TiO2 and OMAT. Variations in the phase function shape at large phase angles are observed in and around the Copernican-aged Jackson crater, including its dark halo, a putative impact melt deposit. Finally, the phase function of the Reiner Gamma Formation behaves more optically immature than is typical for its composition and OMAT, suggesting the visible-to-near-infrared spectrum and phase function respond differently to the unusual regolith evolution and properties at this location.

Lunar Phase Function at 1064 Nm from Lunar Orbiter Laser Altimeter Passive and Active Radiometry

NASA Technical Reports Server (NTRS)

Barker, M. K.; Sun, X.; Mazarico, E.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.

2016-01-01

We present initial calibration and results of passive radiometry collected by the Lunar Orbiter Laser Al- timeter onboard the Lunar Reconnaissance Orbiter over the course of 12 months. After correcting for time- and temperature-dependent dark noise and detector responsivity variations, the LOLA passive radiometry measurements are brought onto the absolute radiance scale of the SELENE Spectral Profiler. The resulting photometric precision is estimated to be approximately 5%. We leverage the unique ability of LOLA to measure normal albedo to explore the 1064 nm phase function's dependence on various geologic parameters. On a global scale, we find that iron abundance and optical maturity (quantified by FeO and OMAT) are the dominant controlling parameters. Titanium abundance (TiO2 ), surface roughness on decimeter to decameter scales, and soil thermophysical properties have a smaller effect, but the latter two are correlated with OMAT, indicating that exposure age is the driving force behind their effects in a globally-averaged sense. The phase function also exhibits a dependence on surface slope at approximately 300 m baselines, possibly the result of mass wasting exposing immature material and/or less space weathering due to reduced sky visibility. Modeling the photometric function in the Hapke framework, we find that, relative to the highlands, the maria exhibit decreased backscattering, a smaller opposition effect (OE) width, and a smaller OE amplitude. Immature highlands regolith has a higher backscattering fraction and a larger OE width compared to mature highlands regolith. Within the maria, the backscattering fraction and OE width show little dependence on TiO2 and OMAT. Variations in the phase function shape at large phase angles are observed in and around the Copernican-aged Jackson crater, including its dark halo, a putative impact melt deposit. Finally, the phase function of the Reiner Gamma Formation behaves more optically immature than is typical for its composition and OMAT, suggesting the visible-to-near-infrared spectrum and phase function respond differently to the unusual regolith evolution and properties at this location.

Lunar Phase Function at 1064 Nm from Lunar Orbiter Laser Altimeter Passive and Active Radiometry

NASA Technical Reports Server (NTRS)

Barker, M. K.; Sun, X.; Mazarico, E.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.

2016-01-01

We present initial calibration and results of passive radiometry collected by the Lunar Orbiter Laser Altimeter onboard the Lunar Reconnaissance Orbiter over the course of 12 months. After correcting for time- and temperature-dependent dark noise and detector responsivity variations, the LOLA passive radiometry measurements are brought onto the absolute radiance scale of the SELENE Spectral Profiler. The resulting photometric precision is estimated to be 5%. We leverage the unique ability of LOLA to measure normal albedo to explore the 1064 nm phase function's dependence on various geologic parameters. On a global scale, we find that iron abundance and optical maturity (quantified by FeO and OMAT) are the dominant controlling parameters. Titanium abundance (TiO2), surface roughness on decimeter to decameter scales, and soil thermo- physical properties have a smaller effect, but the latter two are correlated with OMAT, indicating that exposure age is the driving force behind their effects in a globally-averaged sense. The phase function also exhibits a dependence on surface slope at approximately 300 m baselines, possibly the result of mass wasting exposing immature material and/or less space weathering due to reduced sky visibility. Modeling the photometric function in the Hapke framework, we find that, relative to the highlands, the maria exhibit decreased backscattering, a smaller opposition effect (OE) width, and a smaller OE amplitude. Immature highlands regolith has a higher backscattering fraction and a larger OE width compared to mature highlands regolith. Within the maria, the backscattering fraction and OE width show little dependence on TiO2 and OMAT. Variations in the phase function shape at large phase angles are observed in and around the Copernican-aged Jackson crater, including its dark halo, a putative impact melt deposit. Finally, the phase function of the Reiner Gamma Formation behaves more optically immature than is typical for its composition and OMAT, suggesting the visible-to-near-infrared spectrum and phase function respond differently to the unusual regolith evolution and properties at this location. The phase difference map revealed additional geologically-influenced variations in the phase function's shape. In particular, variations were observed associated with the dark halo around Jackson crater, the impact ejecta of Copernicus and Giordano Bruno, and the Reiner Gamma Formation. For the latter, we 915 found that the phase function behaves more optically immature than the global phase function for its composition and OMAT, suggesting a difference in how the visible-to-near-IR spectrum and phase function respond to the unusual regolith evolution and properties at this location.

Geologic evolution of the Akna Montes-Atropos Tessera region, Venus

NASA Astrophysics Data System (ADS)

Marinangeli, Lucia; Gilmore, Martha S.

2000-05-01

The investigated area comprises an arcuate mountain belt, Akna Montes, in Western Ishtar Terra, associated with an outboard plateau, Atropos Tessera, to the west and a volcanic plateau, Lakshmi Planum, to the east. Eight geologic units have been recognized on the basis of their geomorphic and structural characteristics as they appear on Magellan radar images. Our stratigraphic analysis shows that the geological evolution of the study area can be explained by four main steps: (1) formation of the older substrata of Atropos Tessera and Lakshmi, (2) extensive plains emplacement, (3) an orogenic phase including the formation of Akna Montes, and (4) local emplacement of younger plains. The tectonic evolution shows a deformational sequence characterized by contraction, shear, and topographic relaxation. This sequence is interpreted to be a consequence of the variation of crustal stresses and crustal thickening during orogenic events as observed for terrestrial high plateaus associated with a mountain belt (i.e., Himalaya and Tibet, Andes and Altiplano). In order to estimate the amount of crustal shortening associated with the Akna Montes, we considered two end-members for structural style of the mountain belt: a symmetric fold model and fault-bend fold model. The models are theoretical because terrestrial orogenic belts are often formed by a combination of different compressional structures. However, symmetric and fault-bend faults represent the minimum and maximum crustal shortening, respectively, and thus they do place bounds on the amount of strain recorded by Akna Montes. The first model yields a shortening value less than 1%, whereas a range of 17-34% is derived for the second model. The large difference between these values underscores the importance of fold geometries for estimating strain and to place constraints on geodynamic models for mountain belt formation. On the basis of our study we think that a combination of mantle downwelling and horizontal convergence may provide a good explanation of the geology and tectonics we observed in the Akna Montes-Atropos Tessera region.

The dynamic history of the Trans-Mexican Volcanic Belt and the Mexico subduction zone

NASA Astrophysics Data System (ADS)

Ferrari, Luca; Orozco-Esquivel, Teresa; Manea, Vlad; Manea, Marina

2012-02-01

The Trans-Mexican Volcanic Belt (TMVB) is a 1000 km long Neogene continental arc showing a large variation in composition and volcanic style, and an intra-arc extensional tectonics. It overlies the Rivera and Cocos slabs, which display marked changes in geometry. Geophysical studies indicate that lithospheric mantle is very thin or absent beneath the forearc and arc, the fluids from the slab are released in a 40 to 100 km wide belt beneath the frontal part of the arc, and the lower crust beneath the arc is partially molten. East of 101°W the TMVB is built on a Precambrian to Paleozoic crust with thickness of 50-55 km. West of 101°W the TMVB is underlain by Jurassic to Cenozoic marine and continental arcs with a 35-40 km thick crust. The evolution of the TMVB occurred in four stages: 1) from ~ 20 to 10 Ma the initial andesitic arc moved inland showing progressively drier melting and, eventually, slab melting, suggesting flattening of the subducted slab; 2) since ~ 11 Ma a pulse of mafic volcanism migrated from west to east reaching the Gulf of Mexico by 7 Ma. This mafic lavas marks the lateral propagation of a slab tear, triggered by cessation of subduction beneath Baja California; 3) thereafter, the volcanic front started moving trenchward, with a marked phase of silicic volcanism between 7.5 and 3 Ma, local emplacement of small volume intraplate-like basalts since 5 Ma, and development of extensional faulting. These features are related to slab rollback, enhancing asthenophere flux into the mantle wedge and promoting partial melting of the crust; 4) the modern arc consists of a frontal belt dominated by flux and slab melting, and a rear belt characterized by more differentiated rocks or by mafic lavas with little or no evidence of subduction fluids but higher asthenosphere fingerprint.

Weathering processes and the composition of inorganic material transported through the orinoco river system, Venezuela and Colombia

USGS Publications Warehouse

Stallard, R.F.; Koehnken, L.; Johnsson, M.J.

1991-01-01

The composition of river-borne material in the Orinoco River system is related primarily to erosion regime, which in turn is related to tectonic setting; especially notable is the contrast between material derived from tectonically active mountain belts and that from stable cratonic regions. For a particular morpho-tectonic region, the compositional suites of suspended sediment, bed material, overback deposits, and dissolved phases are fairly uniform are are typically distinct from whose of other regions. For each region, a consistent set of chemical weathering reactions can be formulated to explain the composition of dissolved and solid loads. In developing these formulations, erosion on slopes and storage of solids in soils and alluvial sediments are important considerations. Compositionally verymature sediment is derived from areas of thick soils where erosion is transport limited and from areas where sediments are stored for extended periods of time in alluvial deposits. Compositionally immature sediments are derived from tectonically active mountain belts where erosion is weathering limited. Weathering-limited erosion also is important in the elevated parts of the Guayana Shield within areas of sleep topography. Compared to the mountain belts, sediments derived from elevated parts of the Shield are more mature. A greater degree of chemical weathering seems to be needed to erode the rock types typical of the Shield. The major-element chemistry and mineral composition of sediment delivered by the Orinoco River to the ocean are controlled by rivers that have their headwaters in mountain belts and cross the Llanos, a region of alluvial plains within the foreland basin. The composition of sediments in rivers that drain the Shield seems to be established primarily at the site of soil formation, whereas for rivers that drain the mountain belts, additional weathering occurs during s episodes of storage on alluvial plains as sediments are transported across the Llanos to the main stem of the Orinoco. After mixing into the main stem, there seems to be little subsequent alteration of sediment. ?? 1991.

Mineral potential tracts for orogenic, Carlin-like, and epithermal gold deposits in the Islamic Republic of Mauritania, (phase V, deliverable 69): Chapter H in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

USGS Publications Warehouse

Goldfarb, Richard J.; Marsh, Erin; Anderson, Eric D.; Horton, John D.; Finn, Carol A.; Beaudoin, Georges

2015-01-01

A preliminary evaluation of these gold data can be used to develop broad, firstorder tracts defining favorable and permissive areas for gold resources; detailed metamorphic and structural maps are required for more detailed future tract definition. Such a first-order assessment can, nonetheless, broadly identify four tracts of gold resource potential. Three of these are favorable for discovery of new orogenic gold deposits. One tract, although not favorable, is nevertheless permissive for discovery of epithermal gold deposits. Tract 1 is defined by favorable medium metamorphic grade greenstone belts within vast areas of unfavorable high metamorphic grade, Mesoarchean and Paleoproterozoic granite-gneiss basement of the Rgueïbat Shield. Faults >200 km in length following the general strike of the greenstone belts; lineament intersections with both exposed and buried parts of greenstone belts within 500 m of the surface, as defined by aeromagnetic data (Finn and Anderson, 2015); and areas of banded iron formation (BIF) in the belts are particularly favorable areas for hosting gold resources in orogenic gold deposits within and along the margins of the greenstone belts. Tracts 2 and 3, also for orogenic gold, reflect the favorable Proterozoic-Cambrian metamorphic rocks of the Northern and Southern Mauritanides, with >200-km-long faults following the general strike of the range, and areas underlain by ultramafic and BIF rocks being particularly favorable. Outcrops of Triassic-Jurassic igneous rocks along the margins of the Taoudeni Basin define tract 4, which is permissive for epithermal gold deposits. Although extensive data are lacking for the area, carbonate units along the northern side of the Taoudeni Basin could be considered permissive host rocks for Carlin-type mineralization, but the deep-water carbonate lithologies are typically not favorable for such. 

Morphology control of layer-structured gallium selenide nanowires.

PubMed

Peng, Hailin; Meister, Stefan; Chan, Candace K; Zhang, Xiao Feng; Cui, Yi

2007-01-01

Layer-structured group III chalcogenides have highly anisotropic properties and are attractive materials for stable photocathodes and battery electrodes. We report the controlled synthesis and characterization of layer-structured GaSe nanowires via a catalyst-assisted vapor-liquid-solid (VLS) growth mechanism during GaSe powder evaporation. GaSe nanowires consist of Se-Ga-Ga-Se layers stacked together via van der Waals interactions to form belt-shaped nanowires with a growth direction along the [11-20], width along the [1-100], and height along the [0001] direction. Nanobelts exhibit a variety of morphologies including straight, zigzag, and saw-tooth shapes. These morphologies are realized by controlling the growth temperature and time so that the actual catalysts have a chemical composition of Au, Au-Ga alloy, or Ga. The participation of Ga in the VLS catalyst is important for achieving different morphologies of GaSe. In addition, GaSe nanotubes are also prepared by a slow growth process.

Revegetation increase bird diversity in coastal area of Socorejo, Tuban, East Java - Indonesia

NASA Astrophysics Data System (ADS)

Lestari, Yeni Indah; Edi, Wasito; Alivvy, Alkautsar; Ibadah, Acib Setia; Sari, Fadina Yuliana; Nuraini, Finda; Yanuar, Ahmad; Satriyono, Agus; Riany, Citra Fitrie; Saptarini, Dian; Muzaki, Farid Kamal

2017-06-01

Study to address positive impact of revegetation program to increasing diversity of bird had been conducted in coastal area of Socorejo, Tuban - Indonesia. Field observation conducted during April 2011 (representing pre-revegetation period), April 2015 and May 2016 (representing post-revegetation period). A belt transect (500 meter long and 50 meter width) was used to survey the abundance and species composition of birds community. In general, we identified at least 51 bird species from three observation times. From 2011 to 2016, the numbers of the birds identified are 23, 37 and 37 species; while the Shannon-Wiener diversity indices (H') are 1.865, 2.071 and 2.957, respectively. In addition, there are 11 national or internationally protected species, 3 Indonesian endemic species and 12 migratory species occurred in the area. As a conclusion, the coastal revegetation program provides positive impact by generating habitat function for bird community.

Conservation values and management strategies of coastal windbreaks

NASA Astrophysics Data System (ADS)

Lee, M. J.; Song, G. Z. M.

2015-12-01

Taiwan is surrounded by oceans, so that the citizens' daily lives and the industrial activities in coast areas are exposed to and affected by strong winds and dust storms caused by the winter monsoon. Tree windbreaks present the functions of windproof, dust inhibition, damp-proof, and climate moderation. However, in recent years, the construction of roads, establishment industrial districts, development of recreation areas, building of wind turbines, and the cultivation of local citizens have greatly changed the width and integrity of tree windbreak belts, and in turn affected their functionality. Our study focus on tree windbreaks right next to the estuary of the Zhoushui River in Taiwan. Through environmental investigations, questionnaire surveys for local citizens, and vegetation sureys, the current functions of windbreaks and impacts of human disturbances on windbreaks will be evaluated. The conservation values and management strategies of tree windbreaks will be proposed after all.

Deep conductivity characteristics and preliminary acquaintance of the Lushan earthquake, east edge of Tibetan Plateau, China

NASA Astrophysics Data System (ADS)

Zhou, J.; Wang, X.; Wang, Y.; Min, G.

2013-12-01

1. Introduction The Longmenshan foreland basin developed as a flexural foredeep at western Yangtze Platfrom during the Late Triassic Indosinian orogeny with strong tectonic activity. 2008 Wenchuan earthquake (Mw7.9) happened along the middle segment of the Longmenshan overthrusting belt. 2013 Lushan earthquake (Mw6.6) occurred along the south segment of Longmenshan tectonic zone which belongs to seismic gap during the Wenchuan earthquake. The recent researches ( Yan Zhan etc., 2013; Zhuqi Zhang etc., 2013; Xiwei Xu etc., 2013) indicate that the Lushan earthquake may closely related to the activity of Longmenshan ';s piedmont fault zone while the seismogenic fault and other issues are still controversial. In order to provide an electromagnetic basis in deep earthquake area structure, we detect magnetotelluric(MT) sounding in Lushan earthquake zone to obtain the electrical structure characteristics of Longmenshan's south segment. 2. Data acquisition and processing To research the deep electrical structure of earthquake zone assigning a MT profile through the epicenter which transects the Sichuan platform concave, Longmenshan tectonic belt and Songpan-Ganzi fold system. To analysis the MT data, we carried out the impedance tensor decompositionincluding the swift rotation and bahr method which based on the phase deviation. Ultimately, NLCG method was adopted to inverse MT data. 3. Conclusion The result of MT data discloses deep electrical structure feature of the southern section of Longmenshan overthrusting belt: the burial depth of conductive layer in the upper crust of Songpan-Ganzi plot is larger than that of middle-northern part; there is no conductive zone in Longmenshan high resistance body which connect with the high conductivity layer in the crust of the western section of Songpan-Ganzi plot; there exists a relatively large range of conductive zone in the basin to Longmenshan tectonic belt, which is mostly related to the piedmont of concealed fault zone and resistive intermediate belt at the edge of western basin. Be different form Wenchuan earthquake, Lushan earthquake located in the south of Longmenshan tectonic zone which have a strong connection with the piedmont fault. MT research reveals the difference of the deep electrical structure between the south of Longmenshan tectonic belt and the middle-north belt, from which we can infer that the seismogenic environment are not the same. The epicenter of Lushan earthquake occurred in the east edge of Longmenshan tectonic belt which close to Longmenshan ';s piedmont fault combine with the MT inversion infer that Lushan earthquake has a stronger relationship with Longmenshan ';s piedmont fault. Because of the short term of our work, now further work is ongoing.

The role of Mesozoic sedimentary basin tapers on the formation of Cenozoic crustal shortening structures and foredeep in the western Sichuan Basin, China

NASA Astrophysics Data System (ADS)

Wang, M.

2017-12-01

The foreland basin records important clues of tectonic and sedimentary process of mountain-building, thus to explore its dynamic mechanism on the formation is an important issue of the mountain-basin interaction. The Longmen Shan fold-and-thrust belt and its adjacent Sichuan basin located in the eastern margin of Tibetan Plateau, are one of the most-concerned regions of studying modern mountain-building and seismic process, and are also a natural laboratory of studying the dynamics of the formation and development of foreland basin. However, it still need further explore on the mechanics of the development of the Cenozoic foreland basin and thrust-belts in the western Sichuan Basin. The Longmen Shan thrust belt has experienced multi-stages of tectonics evolution, foreland basin formation and topography growth since Late Triassic, and whether the early formed basin architecture and large Mesozoic sedimentary basin taper can influence the formation and development of the Cenozoic foreland basin and thrust belts? To solve these issues, this project aim to focus on the Cenozoic foreland basin and internal crustal shortening structures in the western Sichuan basin, on the basis of growth critical wedge taper theory. We will reconstruct the shape of multi-phases of sedimentary basin tapers, the temporal-spatial distribution of crustal shortening and thrusting sequences, and analyze the control mechanism of Mesozoic sedimentary basin taper on the formation of Cenozoic foreland basins, and final explore the interaction between the tectonics geomorphology, stress field and dynamic propagation of foreland basin.

Suspended particulate layers and internal waves over the southern Monterey Bay continental shelf: an important control on shelf mud belts?

USGS Publications Warehouse

Cheriton, Olivia M.; McPhee-Shaw, Erika E.; Shaw, William J.; Stanton, Timothy P.; Bellingham, James G.; Storlazzi, Curt D.

2014-01-01

Physical and optical measurements taken over the mud belt on the southern continental shelf of Monterey Bay, California documented the frequent occurrence of suspended particulate matter features, the majority of which were detached from the seafloor, centered 9–33 m above the bed. In fall 2011, an automated profiling mooring and fixed instrumentation, including a thermistor chain and upward-looking acoustic Doppler current profiler, were deployed at 70 m depth for 5 weeks, and from 12 to 16 October a long-range autonomous underwater vehicle performed across-shelf transects. Individual SPM events were uncorrelated with local bed shear stress caused by surface waves and bottom currents. Nearly half of all observed SPM layers occurred during 1 week of the study, 9–16 October 2011, and were advected past the fixed profiling mooring by the onshore phase of semidiurnal internal tide bottom currents. At the start of the 9–16 October period, we observed intense near-bed vertical velocities capable of lifting particulates into the middle of the water column. This “updraft” event appears to have been associated with nonlinear adjustment of high-amplitude internal tides over the mid and outer shelf. These findings suggest that nonlinear internal tidal motions can erode material over the outer shelf and that, once suspended, this SPM can then be transported shoreward to the middle and shallow sections of the mud belt. This represents a fundamental broadening of our understanding of how shelf mud belts may be built up and sustained.

Driver kinematic and muscle responses in braking events with standard and reversible pre-tensioned restraints: validation data for human models.

PubMed

Osth, Jonas; Olafsdóttir, Jóna Marín; Davidsson, Johan; Brolin, Karin

2013-11-01

The objectives of this study are to generate validation data for human models intended for simulation of occupant kinematics in a pre-crash phase, and to evaluate the effect of an integrated safety system on driver kinematics and muscle responses. Eleven male and nine female volunteers, driving a passenger car on ordinary roads, performed maximum voluntary braking; they were also subjected to autonomous braking events with both standard and reversible pre-tensioned restraints. Kinematic data was acquired through film analysis, and surface electromyography (EMG) was recorded bilaterally for muscles in the neck, the upper extremities, and lumbar region. Maximum voluntary contractions (MVCs) were carried out in a driving posture for normalization of the EMG. Seat belt positions, interaction forces, and seat indentions were measured. During normal driving, all muscle activity was below 5% of MVC for females and 9% for males. The range of activity during steady state braking for males and females was 13-44% in the cervical and lumbar extensors, while antagonistic muscles showed a co-contraction of 2.3-19%. Seat belt pre-tension affects both the kinematic and muscle responses of drivers. In autonomous braking with standard restraints, muscle activation occurred in response to the inertial load. With pre-tensioned seat belts, EMG onset occurred earlier; between 71 ms and 176 ms after belt pre-tension. The EMG onset times decreased with repeated trials and were shorter for females than for males. With the results from this study, further improvement and validation of human models that incorporate active musculature will be made possible.

Evidence of water degassing during emplacement and crystallization of 2.7 Ga komatiites from the Agnew-Wiluna greenstone belt, Western Australia

NASA Astrophysics Data System (ADS)

Fiorentini, M. L.; Beresford, S. W.; Stone, W. E.; Deloule, E.

2012-07-01

Komatiites are ancient volcanic rocks, mostly over 2.7 billion years old, which formed through >30% partial melting of the mantle. This study addresses the crucial relationship between volcanology and physical manifestation of primary magmatic water content in komatiites of the Agnew-Wiluna greenstone belt, Western Australia, and documents the degassing processes that occurred during the emplacement and crystallization of these magmas. The Agnew-Wiluna greenstone belt of Western Australia contains three co-genetic komatiite units that (1) display laterally variable volcanological features, including thick cumulates and spinifex-textured units, and (2) were emplaced as both lava flows and intrusions at various locations. Komatiite sills up to 500 m thick contain widespread occurrence of hydromagmatic amphibole in orthocumulate- and mesocumulate-textured rocks, which contain ca. 40-50 wt% MgO and <3 wt% TiO2. Conversely, komatiite flows do not contain any volatile-bearing mineral phases: ~150-m-thick flows only contain vesicles, amygdales and segregation structures, whereas <5-10-m-thick flows lack any textural and petrographic evidence of primary volatile contents. The main results of this study demonstrate that komatiites from the Agnew-Wiluna greenstone belt, irrespective of their initial water content, have degassed upon emplacement, flow and crystallization. More importantly, data show that komatiite flows most likely degassed more water than komatiite intrusions. Komatiite degassing may have indirectly influenced numerous physical and chemical parameters of the water from the primordial oceans and hence indirectly contributed to the creation of a complex zonation at the interface between water and seafloor.

Learning New Sensorimotor Contingencies: Effects of Long-Term Use of Sensory Augmentation on the Brain and Conscious Perception.

PubMed

König, Sabine U; Schumann, Frank; Keyser, Johannes; Goeke, Caspar; Krause, Carina; Wache, Susan; Lytochkin, Aleksey; Ebert, Manuel; Brunsch, Vincent; Wahn, Basil; Kaspar, Kai; Nagel, Saskia K; Meilinger, Tobias; Bülthoff, Heinrich; Wolbers, Thomas; Büchel, Christian; König, Peter

2016-01-01

Theories of embodied cognition propose that perception is shaped by sensory stimuli and by the actions of the organism. Following sensorimotor contingency theory, the mastery of lawful relations between own behavior and resulting changes in sensory signals, called sensorimotor contingencies, is constitutive of conscious perception. Sensorimotor contingency theory predicts that, after training, knowledge relating to new sensorimotor contingencies develops, leading to changes in the activation of sensorimotor systems, and concomitant changes in perception. In the present study, we spell out this hypothesis in detail and investigate whether it is possible to learn new sensorimotor contingencies by sensory augmentation. Specifically, we designed an fMRI compatible sensory augmentation device, the feelSpace belt, which gives orientation information about the direction of magnetic north via vibrotactile stimulation on the waist of participants. In a longitudinal study, participants trained with this belt for seven weeks in natural environment. Our EEG results indicate that training with the belt leads to changes in sleep architecture early in the training phase, compatible with the consolidation of procedural learning as well as increased sensorimotor processing and motor programming. The fMRI results suggest that training entails activity in sensory as well as higher motor centers and brain areas known to be involved in navigation. These neural changes are accompanied with changes in how space and the belt signal are perceived, as well as with increased trust in navigational ability. Thus, our data on physiological processes and subjective experiences are compatible with the hypothesis that new sensorimotor contingencies can be acquired using sensory augmentation.

Learning New Sensorimotor Contingencies: Effects of Long-Term Use of Sensory Augmentation on the Brain and Conscious Perception

PubMed Central

Schumann, Frank; Keyser, Johannes; Goeke, Caspar; Krause, Carina; Wache, Susan; Lytochkin, Aleksey; Ebert, Manuel; Brunsch, Vincent; Wahn, Basil; Kaspar, Kai; Nagel, Saskia K.; Meilinger, Tobias; Bülthoff, Heinrich; Wolbers, Thomas; Büchel, Christian; König, Peter

2016-01-01

Theories of embodied cognition propose that perception is shaped by sensory stimuli and by the actions of the organism. Following sensorimotor contingency theory, the mastery of lawful relations between own behavior and resulting changes in sensory signals, called sensorimotor contingencies, is constitutive of conscious perception. Sensorimotor contingency theory predicts that, after training, knowledge relating to new sensorimotor contingencies develops, leading to changes in the activation of sensorimotor systems, and concomitant changes in perception. In the present study, we spell out this hypothesis in detail and investigate whether it is possible to learn new sensorimotor contingencies by sensory augmentation. Specifically, we designed an fMRI compatible sensory augmentation device, the feelSpace belt, which gives orientation information about the direction of magnetic north via vibrotactile stimulation on the waist of participants. In a longitudinal study, participants trained with this belt for seven weeks in natural environment. Our EEG results indicate that training with the belt leads to changes in sleep architecture early in the training phase, compatible with the consolidation of procedural learning as well as increased sensorimotor processing and motor programming. The fMRI results suggest that training entails activity in sensory as well as higher motor centers and brain areas known to be involved in navigation. These neural changes are accompanied with changes in how space and the belt signal are perceived, as well as with increased trust in navigational ability. Thus, our data on physiological processes and subjective experiences are compatible with the hypothesis that new sensorimotor contingencies can be acquired using sensory augmentation. PMID:27959914

Suspended particulate layers and internal waves over the southern Monterey Bay continental shelf: An important control on shelf mud belts?

NASA Astrophysics Data System (ADS)

Cheriton, Olivia M.; McPhee-Shaw, Erika E.; Shaw, William J.; Stanton, Timothy P.; Bellingham, James G.; Storlazzi, Curt D.

2014-01-01

Physical and optical measurements taken over the mud belt on the southern continental shelf of Monterey Bay, California documented the frequent occurrence of suspended particulate matter features, the majority of which were detached from the seafloor, centered 9-33 m above the bed. In fall 2011, an automated profiling mooring and fixed instrumentation, including a thermistor chain and upward-looking acoustic Doppler current profiler, were deployed at 70 m depth for 5 weeks, and from 12 to 16 October a long-range autonomous underwater vehicle performed across-shelf transects. Individual SPM events were uncorrelated with local bed shear stress caused by surface waves and bottom currents. Nearly half of all observed SPM layers occurred during 1 week of the study, 9-16 October 2011, and were advected past the fixed profiling mooring by the onshore phase of semidiurnal internal tide bottom currents. At the start of the 9-16 October period, we observed intense near-bed vertical velocities capable of lifting particulates into the middle of the water column. This "updraft" event appears to have been associated with nonlinear adjustment of high-amplitude internal tides over the mid and outer shelf. These findings suggest that nonlinear internal tidal motions can erode material over the outer shelf and that, once suspended, this SPM can then be transported shoreward to the middle and shallow sections of the mud belt. This represents a fundamental broadening of our understanding of how shelf mud belts may be built up and sustained.

Hanle effect in nonmonochromatic laser light

NASA Astrophysics Data System (ADS)

Ryan, R. E.; Bergeman, T. H.

1991-06-01

We report results of calculations on the Hanle effect in a J=0⇆J=1 atomic transition with three types of model fluctuating light fields: (a) the Brownian-motion phase-diffusion field, as produced in recent experiments by Arnett et al. [Phys. Rev. A 41, 2580 (1990)]; (b) Gaussian amplitude fluctuations; and (c) the chaotic field model, in which real and imaginary parts of the electric-field amplitude fluctuate. For the stochastic density-matrix equations, we use methods developed by Zoller and co-workers [e.g., Dixit, Zoller, and Lambropoulos, Phys. Rev. A 21, 1289 (1980)] employing the Fokker-Planck operator and leading to matrix continued-fraction expansions. The Hanle effect is of interest as a prototype for multisublevel atomic transitions. The width of the Hanle dip at zero magnetic field reflects the tendency of the light field to preserve the coherence between excited-state sublevels. For monochromatic light, the Hanle dip width increases as the square root of light intensity. When the laser bandwidth increases, power broadening of the coherence dip normally decreases. However, with the Brownian-motion phase-diffusion model, if the laser spectral profile is nearly Gaussian, broadening the laser up to several times the natural width of the atomic line does not diminish the Hanle dip width. With amplitude fluctuations, even in the limit of monochromatic light, power broadening of the Hanle dip with intensity is reduced by one-third to one-half depending on the particular model.

SPECTROSCOPIC AND PHOTOMETRIC VARIABILITY IN THE A0 SUPERGIANT HR 1040

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

Corliss, David J.; Morrison, Nancy D.; Adelman, Saul J., E-mail: david.corliss@wayne.edu

2015-12-15

A time-series analysis of spectroscopic and photometric observables of the A0 Ia supergiant HR 1040 has been performed, including equivalent widths, radial velocities, and Strömgren photometric indices. The data, obtained from 1993 through 2007, include 152 spectroscopic observations from the Ritter Observatory 1 m telescope and 269 Strömgren photometric observations from the Four College Automated Photoelectric Telescope. Typical of late B- and early A-type supergiants, HR 1040 has a highly variable Hα profile. The star was found to have an intermittent active phase marked by correlation between the Hα absorption equivalent width and blue-edge radial velocity and by photospheric connectionsmore » observed in correlations to equivalent width, second moment and radial velocity in Si ii λλ6347, 6371. High-velocity absorption (HVA) events were observed only during this active phase. HVA events in the wind were preceded by photospheric activity, including Si ii radial velocity oscillations 19–42 days prior to onset of an HVA event and correlated increases in Si ii W{sub λ} and second moment from 13 to 23 days before the start of the HVA event. While increases in various line equivalent widths in the wind prior to HVA events have been reported in the past in other stars, our finding of precursors in enhanced radial velocity variations in the wind and at the photosphere is a new result.« less

Nonlinear optical properties of As20S80 system chalcogenide glass using Z-scan and its strip waveguide under bandgap light using the self-phase modulation

NASA Astrophysics Data System (ADS)

Zou, L. E.; He, P. P.; Chen, B. X.; Iso, M.

2017-02-01

Optical nonlinearities in the undoped As20S80, low doped P2As20S78 and Sn1As20S79 chacogenide glasses are investigated by using Z-scan method. These experiments show that at 1064 nm the figure of merit (FOM) for As20S80 is ˜1.02, while for Sn1As20S79 increases to ˜1.42, and for P2As20S78 decreases to ˜0.83. These resulted data indicate the addition of Sn in As20S80 system chalcogenide glass can enhance FOM due to creating narrow energy gaps. In addition, the self-phase modulation (SPM) width experiment for Sn1As20S79 strip waveguide displays that the full width half maximum (FWHM) of spectral width increases approximately 0.8 nm under the induction of bandgap light, meaning that the bandgap light can induce to enhance its optical nonlinearity with the nonlinear refractive index of n2≅5.27×10-14 cm2/W.

Procurement specifications report. IMBLS phase B-4

NASA Technical Reports Server (NTRS)

1970-01-01

Procurement specifications to provide vendors of space systems with supporting information to accurately price the selected major buy items are illustrated. In performing this task, rigid constraints on specifications and drawing details are avoided beyond those necessary to define basic requirements. Described are digital processing equipment, mass spectrometer, body mass measuring device, sensors, bio-belt power source, vision tester and instrumentation for a biochemical station.

Shear Wave Structure in the Lithosphere of Texas from Ambient Noise Tomography

NASA Astrophysics Data System (ADS)

Yao, Y.; Li, A.

2014-12-01

Texas contains several distinct tectonic provinces, the Laurentia craton, the Ouachita belt, and the Gulf coastal plain. Although numerous geophysical experiments have been conducted in Texas for petroleum exploration, the lithosphere structure of Texas has not been well studied. We present here the Texas-wide shear wave structure using seismic ambient noise data recorded at 87 stations from the Transportable Array of the USArray between March 2010 and February 2011. Rayleigh wave phase velocities between pairs of stations are obtained by cross-correlating long ambient noise sequences and are used to develop phase velocity maps from 6 to 40 s. These measured phase velocities are used to construct 1-D and 3-D shear wave velocity models, which consist of four crust layers and one upper mantle layer. Shear wave velocity maps reveal a close correlation with major geological features. From the surface to 25 km depth, Positive anomalies coincide with the Laurentia craton, and negative anomalies coincide with the continental margin. The boundary of positive-negative anomaly perfectly matches the Ouachita belt. The Llano Uplift is imaged as the highest velocity through the mid-crust because the igneous rock forming the uplift has faster seismic velocity than the normal continental crust. Similarly, three small high-velocity areas exist beneath the Waco Uplift, Devils River Uplift, and Benton Uplift, even though surface geological traces are absent in these areas. The lowest velocity at the shallow crust appears in northeastern and southeastern Texas separated by the San Marcos Arch, correlating with thick sediment layers. An exceptional low velocity is imaged in southernmost Texas in the lower crust and upper mantle, probably caused by subducted wet oceanic crust before the rifting in the Gulf of Mexico. In the uppermost mantle, positive shear wave anomalies extend southeastward from the Ouachita belt to the Gulf coast, likely evidencing the subducted oceanic lithosphere during the Ouachita orogeny. This observation need be further tested using long period surface wave dispersions from earthquakes, which help to improve model resolution in the upper mantle.

Textures and compositions of cobalt pentlandite and cobaltian mackinawite from the Madan-Kudan copper deposit, Khetri Copper Belt, Rajasthan, India

NASA Astrophysics Data System (ADS)

Baidya, Abu Saeed; Sen, Atlanta; Pal, Dipak C.

2018-06-01

The Khetri Copper Belt (KCB), a part of the Proterozoic Delhi-Aravalli fold belt in western India, hosts several Cu deposits, which are known to contain considerable Au, Ag, Co and Ni. Although many Co-bearing phases have been reported from the KCB and adjacent areas, detailed textural and geochemical data are either unavailable or scant except for mackinawite. In this study, we describe the textures and compositions (determined by EPMA) of two very rare Co-rich phases, namely cobaltian mackinawite (containing up to 12.68 wt.% Co, 1.90 wt.% Ni and 2.52 wt.% Cu) and cobalt-pentlandite (containing up to 49.30 wt.% Co and 10.19 wt.% Ni), identified based on composition, from the Madan-Kudan deposit. To the best of our knowledge, neither cobalt-pentlandite nor such highly Co-rich mackinawite have previously been reported from this area. The common sulphide minerals viz. chalcopyrite, pyrrhotite and rare pyrite occur in chalcopyrite-pyrrhotite ± pyrite-magnetite-chlorite-blue amphibole (Cl-rich hastingsite-pargasite-sadanagaite) ± marialitic scapolite ± allanite ± uraninite veins in amphibole-bearing feldspathic quartzite and garnetiferous chlorite schist. Cobaltian mackinawite is invariably associated with chalcopyrite and occurs as exsolution and inclusion within chalcopyrite or outside, but at the contact of chalcopyrite. On the other hand, cobalt-pentlandite is invariably associated with pyrrhotite and shows similar textural relation with pyrrhotite as that of mackinawite with chalcopyrite. Mineralogically diverse undeformed sulphide veins comprising Cl-rich amphibole and locally Cl-rich marialitic scapolite suggests epigenetic hydrothermal mineralization involving Cl-rich saline fluid in the Madan-Kudan deposit. Transport of metals, derived from a mafic source rock with high intrinsic Ni:Co ratio, by Cl-rich fluid can suitably explain the high Co:Ni ratio of the studied ore minerals. Presence of such highly Co-rich phases and other circumstantial evidences, enumerated in this work, are consistent with variants of Fe oxide (-Cu-Au) (IOCG) style mineralization, at least for some stages of mineralization in the Madan-Kudan deposit.

A Coordinated X-Ray and Optical Campaign of the Nearest Massive Eclipsing Binary, Delta Orionis Aa. II. X-Ray Variability

NASA Technical Reports Server (NTRS)

Nichols, J.; Huenemoerder, D. P.; Corcoran, M. F.; Waldron, W.; Naze, Y.; Pollock, A. M. T.; Moffat, A. F. J.; Lauer, J.; Shenar, T.; Russell, C. M. P.;

Temporal and Latitudinal Variations of the Length-Scales and Relative Intensities of the Chromospheric Network

NASA Astrophysics Data System (ADS)

Raju, K. P.

2018-05-01

The Calcium K spectroheliograms of the Sun from Kodaikanal have a data span of about 100 years and covers over 9 solar cycles. The Ca line is a strong chromospheric line dominated by chromospheric network and plages which are good indicators of solar activity. Length-scales and relative intensities of the chromospheric network have been obtained in the solar latitudes from 50 degree N to 50 degree S from the spectroheliograms. The length-scale was obtained from the half-width of the two-dimensional autocorrelation of the latitude strip which gives a measure of the width of the network boundary. As reported earlier for the transition region extreme ultraviolet (EUV) network, relative intensity and width of the chromospheric network boundary are found to be dependent on the solar cycle. A varying phase difference has been noticed in the quantities in different solar latitudes. A cross-correlation analysis of the quantities from other latitudes with ±30 degree latitude revealed an interesting phase difference pattern indicating flux transfer. Evidence of equatorward flux transfer has been observed. The average equatorward flux transfer was estimated to be 5.8 ms-1. The possible reasons of the drift could be meridional circulation, torsional oscillations, or the bright point migration. Cross-correlation of intensity and length-scale from the same latitude showed increasing phase difference with increasing latitude. We have also obtained the cross correlation of the quantities across the equator to see the possible phase lags in the two hemispheres. Signatures of lags are seen in the length scales of southern hemisphere near the equatorial latitudes, but no such lags in the intensity are observed. The results have important implications on the flux transfer over the solar surface and hence on the solar activity and dynamo.

An investigation into a micro-sized droplet impinging on a surface with sharp wettability contrast

NASA Astrophysics Data System (ADS)

Lim, C. Y.; Lam, Y. C.

2014-10-01

An experimental investigation was conducted into a micro-sized droplet jetted onto a surface with sharp wettability contrast. The dynamics of micro-sized droplet impingement on a sharp wettability contrast surface, which is critical in inkjet printing technology, has not been investigated in the literature. Hydrophilic lines with line widths ranging from 27 to 53 µm, and contact angle ranging from 17° to 77°, were patterned on a hydrophobic surface with a contact angle of 107°. Water droplets with a diameter of 81 µm were impinged at various offset distances from the centre of the hydrophilic line. The evolution of the droplet upon impingement can be divided into three distinct phases, namely the kinematic phase, the translating phase where the droplet moves towards the centre of the hydrophilic line, and the conforming phase where the droplet spreads along the line. The key parameters affecting the conformability of the droplet to the hydrophilic line pattern are the ratio of the line width to the initial droplet diameter and the contact angle of the hydrophilic line. The droplet will only conform completely to the hydrophilic pattern if the line width is not overly small relative to the droplet and the contact angle of the hydrophilic line is sufficiently low. The impact offset distance does not affect the final shape and final location of the droplet, as long as part of the droplet touches the hydrophilic line upon impingement. This process has a significant impact on inkjet printing technology as high accuracy of inkjet droplet deposition and shape control can be achieved through wettability patterning.

Optimal entrainment of circadian clocks in the presence of noise

NASA Astrophysics Data System (ADS)

Monti, Michele; Lubensky, David K.; ten Wolde, Pieter Rein

2018-03-01

Circadian clocks are biochemical oscillators that allow organisms to estimate the time of the day. These oscillators are inherently noisy due to the discrete nature of the reactants and the stochastic character of their interactions. To keep these oscillators in sync with the daily day-night rhythm in the presence of noise, circadian clocks must be coupled to the dark-light cycle. In this paper, we study the entrainment of phase oscillators as a function of the intrinsic noise in the system. Using stochastic simulations, we compute the optimal coupling strength, intrinsic frequency, and shape of the phase-response curve, that maximize the mutual information between the phase of the clock and time. We show that the optimal coupling strength and intrinsic frequency increase with the noise, but that the shape of the phase-response curve varies nonmonotonically with the noise: in the low-noise regime, it features a dead zone that increases in width as the noise increases, while in the high-noise regime, the width decreases with the noise. These results arise from a tradeoff between maximizing stability—noise suppression—and maximizing linearity of the input-output, i.e., time-phase, relation. We also show that three analytic approximations—the linear-noise approximation, the phase-averaging method, and linear-response theory—accurately describe different regimes of the coupling strength and the noise.

Formation of chocolate-tablet boudins: Results from scaled analogue models

NASA Astrophysics Data System (ADS)

Zulauf, J.; Zulauf, G.; Göttlich, J.; Peinl, M.

2014-11-01

We used power-law viscous plasticine as a rock analogue to simulate chocolate tablet boudinage of rocks undergoing dislocation creep. A competent plasticine layer, oriented perpendicular to the main shortening direction, Z, underwent two phases of plane strain in a weaker plasticine matrix, with the principal stretching axis, X, and the axis of no-change, Y, replacing each other from the first to the second phase. In each phase of plane strain, boudinage was controlled by an initial phase of viscous necking followed by extension fracture along the neck domain. Increase in the magnitude of finite strain (e) and decrease in layer thickness (Hi) result in a decrease in the boudin width (Wa) and an increase in the number of boudins (N). Given the viscosity ratio between layer and matrix (m) is higher than ca. 5, the number of boudins decreases and the boudin width increases with increasing values of m. An unexpected result of the present study is that in each experiment, the number of boudins was significantly higher during the second phase of plane strain. This difference should be related to additional drag of the matrix plasticine on the stiff layer in the neck domains formed during the first phase of boudinage. The aspect ratio of the second generation of boudins (Wd = Wa/Hi) is compatible with aspect ratios of natural boudins and with aspect ratios calculated using analytical solutions.

Late Pliocene-Quaternary evolution of outermost hinterland basins of the Northern Apennines (Italy), and their relevance to active tectonics

NASA Astrophysics Data System (ADS)

Sani, Federico; Bonini, Marco; Piccardi, Luigi; Vannucci, Gianfranco; Delle Donne, Dario; Benvenuti, Marco; Moratti, Giovanna; Corti, Giacomo; Montanari, Domenico; Sedda, Lorenzo; Tanini, Chiara

2009-10-01

We examine the tectonic evolution and structural characteristics of the Quaternary intermontane Mugello, Casentino, and Sansepolcro basins, in the Northern Apennines fold-and-thrust belt. These basins have been classically interpreted to have developed under an extensional regime, and to mark the extension-compression transition. The results of our study have instead allowed framing the formation of these basins into a compressive setting tied to the activity of backthrust faults at their northeastern margin. Syndepositional activity of these structures is manifested by consistent architecture of sediments and outcrop-scale deformation. After this phase, the Mugello and Sansepolcro basins experienced a phase of normal faulting extending from the middle Pleistocene until Present. Basin evolution can be thus basically framed into a two-phase history, with extensional tectonics superposed onto compressional structures. Analysis of morphologic features has revealed the occurrence of fresh fault scarps and interaction of faulting with drainage systems, which have been interpreted as evidence for potential ongoing activity of normal faults. Extensional tectonics is also manifested by recent seismicity, and likely caused the strong historical earthquakes affecting the Mugello and Sansepolcro basins. Qualitative comparison of surface information with depth-converted seismic data suggests the basins to represent discrete subsiding areas within the seismic belt extending along the axial zone of the Apennines. The inferred chronology of deformation and the timing of activity of normal faults have an obvious impact on the elaboration of seismic hazard models.

Exciting an Initially Cold Asteroid Belt Through a Planetary Instability

NASA Astrophysics Data System (ADS)

Deienno, Rogerio; Izidoro, Andre; Morbidelli, Alessandro; Gomes, Rodney; Nesvorny, David; Raymond, Sean N.

2018-04-01

The main asteroid belt (MB) is low in mass but dynamically excited, with much larger eccentricities and inclinations than the planets. In recent years, the Grand Tack model has been the predominant model capable of reconciling the formation of the terrestrial planets with a depleted but excited MB. Despite this success, the Grand Tack is still not generally accepted because of uncertainties in orbital migration. It was recently proposed that chaotic early evolution of Jupiter and Saturn could excite the initially cold MB. However, hydrodynamical simulations predict that the giant planets should generally emerge from the gas disk phase on orbits characterized by resonant and regular motion. Here we propose a new mechanism to excite the MB during the giant planets' ('Nice model') instability, which is expected to have included repeated close encounters between Jupiter and one or more ice giants ('Jumping Jupiter' -- JJ). We show that when Jupiter temporarily reaches a high enough level of excitation, both in eccentricity and inclination, it induces strong forced vectors of eccentricity and inclination within the MB region. Because during the JJ instability Jupiter's orbit 'jumps' around, forced vectors keep changing both in magnitude and phase throughout the whole MB region. The entire cold primordial MB can thus be excited as a natural outcome of the JJ instability. Furthermore, we show that the subsequent evolution of the Solar System is capable of reshaping the resultant MB to its present day orbital state, and that a strong mass depletion is always associated to the JJ instability phase.

Effect of potassium perfluorooctanesulfonate, perfluorooctanoate and octanesulfonate on the phase transition of dipalmitoylphosphatidylcholine (DPPC) bilayers

PubMed Central

Xie, W.; Kania-Korwel, I.; Bummer, P. M.; Lehmler, H.-J.

2007-01-01

Summary Perfluorooctanesulfonic acid (PFOS) is a persistent environmental pollutant that may cause adverse effects by inhibiting pulmonary surfactant. To gain further insights in this potential mechanism of toxicity, we investigated the interaction of PFOS potassium salt with dipalmitoylphosphatidylcholine (DPPC) – the major component of pulmonary surfactant – using steady-state fluorescence anisotropy spectroscopy and DSC (differential scanning calorimetry). In addition, we investigated the interactions of two structurally related compounds, perfluorooctanoic acid (PFOA) and octanesulfonic acid (OS) potassium salt, with DPPC. In the fluorescence experiments a linear depression of the main phase transition temperature of DPPC (Tm) and an increased peak width was observed with increasing concentration of all three compounds, both using 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene p-toluenesulfonate (TMA-DPH) as fluorescent probes. PFOS caused an effect on Tm and peak width at much lower concentrations because of its increased tendency to partition onto DPPC bilayers, i.e., the partition coefficients decrease in the K(PFOS) > K(PFOA) ≫ K(OS). Similar to the fluorescence anisotropy measurements, all three compounds caused a linear depression in the onset of the main phase transition temperature and a significant peak broadening in the DSC experiments, with PFOS having the most pronounced effect of the peak width. The effect of PFOS and other fluorinated surfactants on DPPC in both mono- and bilayers may be one mechanism by which these compounds causes adverse biological effects. PMID:17349969

Design of a nanopatterned long focal-length planar focusing collector for concentrated solar power

NASA Astrophysics Data System (ADS)

Ding, Qing; Choubal, Aakash; Toussaint, Kimani C.

2017-02-01

Concentrated solar power (CSP) facilities heavily utilize parabolic troughs to collect and concentrate sunlight onto receivers that deliver solar thermal energy to heat engines for generating electricity. However, parabolic troughs are bulky and heavy and result in a large capital investment for CSP plants, thereby making it difficult for CSP technology to be competitive with photovoltaics. We present the design of a planar focusing collector (PFC) with focal length beyond the micron scale. The PFC design is based on the use of a nanostructured silver surface for linearly polarized singlewavelength light. The designed PFC consists of metallic nanogrooves on a dielectric substrate. The geometric properties, namely the width and depth, of a single-unit nanogroove allows for full control of the optical phase at desired spatial coordinates along the nanogroove short-axis for a single wavelength. Moreover, we show numerically that such phase control can be used to construct a phase front that mimics that of a cylindrical lens. In addition, we determine the concentration ratio by comparing the width of our PFC design to the cross-sectional width of its focal spot. We also determine the conversion efficiency at long focal lengths by evaluating the ratio of the collected optical power to the incoming optical power. Finally, we examine the focusing behavior across multiple wavelengths and angles of incidence. Our work shows how nano-optics and plasmonics could contribute to this important area of CSP technology.

A Coordinated X-Ray and Optical Campaign of the Nearby Massive Binary Sigma Orionis Aa. II; X-Ray Variability

NASA Technical Reports Server (NTRS)

Nichols, J.; Huenemoerder, D. P.; Corcoran, M. F.; Waldron, W.; Naze, Y; Pollock, A. M. T.; Moffat, A. F. J.; Lauer, J.; Shenar, T.; Russell, C. M. P.;

The Study of Phase-shift Super-Frequency Induction Heating Power Supply

NASA Astrophysics Data System (ADS)

Qi, Hairun; Peng, Yonglong; Li, Yabin

This paper combines pulse-width phase-shift power modulation with fixed-angle phase-locked-control to adjust the inverter's output power, this method not only meets the work conditions of voltage inverter, but also realizes the large-scale of power modulation, and the main circuit is simple, the switching devices realize soft switching. This paper analyzes the relationship between the output power and phase-shift angle, the control strategy is simulated by Matlab/Simulink, and the results show that the method is feasible and meets the theoretical analysis

Phase-locked patterns of the Kuramoto model on 3-regular graphs

NASA Astrophysics Data System (ADS)

DeVille, Lee; Ermentrout, Bard

2016-09-01

We consider the existence of non-synchronized fixed points to the Kuramoto model defined on sparse networks: specifically, networks where each vertex has degree exactly three. We show that "most" such networks support multiple attracting phase-locked solutions that are not synchronized and study the depth and width of the basins of attraction of these phase-locked solutions. We also show that it is common in "large enough" graphs to find phase-locked solutions where one or more of the links have angle difference greater than π/2.

Phase-locked patterns of the Kuramoto model on 3-regular graphs.

PubMed

DeVille, Lee; Ermentrout, Bard

2016-09-01

We consider the existence of non-synchronized fixed points to the Kuramoto model defined on sparse networks: specifically, networks where each vertex has degree exactly three. We show that "most" such networks support multiple attracting phase-locked solutions that are not synchronized and study the depth and width of the basins of attraction of these phase-locked solutions. We also show that it is common in "large enough" graphs to find phase-locked solutions where one or more of the links have angle difference greater than π/2.

Phase-sensitive reflection technique for characterization of a fabry-perot interferometer.

PubMed

Slagmolen, B J; Gray, M B; Baigent, K G; McClelland, D E

2000-07-20

Using a radio frequency coherent modulation and demodulation technique, we explicitly measure both the amplitude and the phase response of Fabry-Perot interferometers in reflection. This allows us to differentiate clearly between overcoupled and undercoupled cavities and allows a detailed measurement of the full width at half-maximum, the free spectral range, and the finesse of the cavities.

PHYSICAL EFFECTS OCCURRING DURING GENERATION AND AMPLIFICATION OF LASER RADIATION: Spatial phase fluctuations of the fundamental laser mode caused by spontaneous emission

NASA Astrophysics Data System (ADS)

Belinskiĭ, A. V.; Chirkin, Anatolii S.

1989-02-01

A calculation is reported of the degree of spatial coherence of the fundamental radiation mode subject to phase fluctuations in space. It is shown that the degree of spatial coherence (within the beam width) is perturbed only slightly by these fluctuations, compared with subthreshold excitation of higher transverse modes.

Sound Shell Model for Acoustic Gravitational Wave Production at a First-Order Phase Transition in the Early Universe.

PubMed

Hindmarsh, Mark

2018-02-16

A model for the acoustic production of gravitational waves at a first-order phase transition is presented. The source of gravitational radiation is the sound waves generated by the explosive growth of bubbles of the stable phase. The model assumes that the sound waves are linear and that their power spectrum is determined by the characteristic form of the sound shell around the expanding bubble. The predicted power spectrum has two length scales, the average bubble separation and the sound shell width when the bubbles collide. The peak of the power spectrum is at wave numbers set by the sound shell width. For a higher wave number k, the power spectrum decreases to k^{-3}. At wave numbers below the inverse bubble separation, the power spectrum goes to k^{5}. For bubble wall speeds near the speed of sound where these two length scales are distinguished, there is an intermediate k^{1} power law. The detailed dependence of the power spectrum on the wall speed and the other parameters of the phase transition raises the possibility of their constraint or measurement at a future space-based gravitational wave observatory such as LISA.

Sound Shell Model for Acoustic Gravitational Wave Production at a First-Order Phase Transition in the Early Universe

NASA Astrophysics Data System (ADS)

Hindmarsh, Mark

2018-02-01

A model for the acoustic production of gravitational waves at a first-order phase transition is presented. The source of gravitational radiation is the sound waves generated by the explosive growth of bubbles of the stable phase. The model assumes that the sound waves are linear and that their power spectrum is determined by the characteristic form of the sound shell around the expanding bubble. The predicted power spectrum has two length scales, the average bubble separation and the sound shell width when the bubbles collide. The peak of the power spectrum is at wave numbers set by the sound shell width. For a higher wave number k , the power spectrum decreases to k-3. At wave numbers below the inverse bubble separation, the power spectrum goes to k5. For bubble wall speeds near the speed of sound where these two length scales are distinguished, there is an intermediate k1 power law. The detailed dependence of the power spectrum on the wall speed and the other parameters of the phase transition raises the possibility of their constraint or measurement at a future space-based gravitational wave observatory such as LISA.

Study of variation in thermal width of nematic and induced smectic ordering phase of citric acid (CA) and 4-heptyloxybenzoic acid (7OBA) hydrogen bonded liquid crystal complexes

NASA Astrophysics Data System (ADS)

Sundaram, S.; Jayaprakasam, R.; Praveena, R.; Rajasekaran, T. R.; Senthil, T. S.; Vijayakumar, V. N.

2018-01-01

Hydrogen-bonded liquid crystals (HBLCs) have been derived from nonmesogenic citric acid (CA) and mesogenic 4-heptyloxybenzoic acid (7OBA) yielding a highly ordered smectic C (Sm C) phase along with the new smectic X (Sm X) phase which has been identified as fingerprint-type texture. Optical (polarizing optical microscopy), thermal (differential scanning calorimetry) and structural (Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy) properties are studied. A noteworthy observation is that the intermolecular H-bond (between CA and 7OBA) influences on its melting point and clearing temperature of the HBLCs which exhibits lower value than those of the individual compounds. A typical extended mesophase region has been observed in the present complex while varying the mixture ratio (1:1 to 1:3) than those of individual compounds. The change in the ratio of the mesogenic compound in the mixture alters thermal properties such as enthalpy value and thermal span width in nematic (N) region of HBLC complex. Optical tilt angle measurement of CA+7OBA in Sm C phase has been discussed to identify the molecular position in the mesophase.

Condition-Based Conveyor Belt Replacement Strategy in Lignite Mines with Random Belt Deterioration

NASA Astrophysics Data System (ADS)

Blazej, Ryszard; Jurdziak, Leszek

2017-12-01

In Polish lignite surface mines, condition-based belt replacement strategies are applied in order to assure profitable refurbishment of worn out belts performed by external firms specializing in belt maintenance. In two of three lignite mines, staff asses belt condition subjectively during visual inspections. Only one mine applies specialized diagnostic device (HRDS) allowing objective magnetic evaluation of belt core condition in order to choose the most profitable moment for the dismantling of worn out belt segments from conveyors and sending them to the maintenance firm which provides their refurbishment. This article describes the advantages of a new diagnostic device called DiagBelt. It was developed at the Faculty of Geoengineering, Mining and Geology, Wroclaw University of Science and Technology. Economic gains from its application are calculated for the lignite mine and for the belt maintenance firm, taking into account random life (durability) of new and reconditioned belts (after the 1st and the 2nd refurbishment). Recursive calculations for following years allow the estimation of the length and costs of replaced, reconditioned and purchased belts on an annual basis, while the use of the Monte Carlo method allows the estimation of their variability caused by random deterioration of belts. Savings are obtained due to better selection of moments (times) for the replacement of belt segments and die to the possibility to qualify worn out belts for refurbishment without the need to remove their covers. In effect, increased belt durability and lowered share of waste belts (which were not qualified for reconditioning) create savings which can quickly cover expenditures on new diagnostic tools and regular belt inspections in the mine.

Paleocene Wilcox cross-shelf channel-belt history and shelf-margin growth: Key to Gulf of Mexico sediment delivery

NASA Astrophysics Data System (ADS)

Zhang, Jinyu; Steel, Ronald; Ambrose, William

2017-12-01

Shelf margins prograde and aggrade by the incremental addition of deltaic sediments supplied from river channel belts and by stored shoreline sediment. This paper documents the shelf-edge trajectory and coeval channel belts for a segment of Paleocene Lower Wilcox Group in the northern Gulf of Mexico based on 400 wireline logs and 300 m of whole cores. By quantitatively analyzing these data and comparing them with global databases, we demonstrate how varying sediment supply impacted the Wilcox shelf-margin growth and deep-water sediment dispersal under greenhouse eustatic conditions. The coastal plain to marine topset and uppermost continental slope succession of the Lower Wilcox shelf-margin sediment prism is divided into eighteen high-frequency ( 300 ky duration) stratigraphic sequences, and further grouped into 5 sequence sets (labeled as A-E from bottom to top). Sequence Set A is dominantly muddy slope deposits. The shelf edge of Sequence Sets B and C prograded rapidly (> 10 km/Ma) and aggraded modestly (< 80 m/Ma). The coeval channel belts are relatively large (individually averaging 11-13 m thick) and amalgamated. The water discharge of Sequence Sets B and C rivers, estimated by channel-belt thickness, bedform type, and grain size, is 7000-29,000 m3/s, considered as large rivers when compared with modern river databases. In contrast, slow progradation (< 10 km/Ma) and rapid aggradation (> 80 m/Ma) characterizes Sequence Sets D and E, which is associated with smaller (9-10 m thick on average) and isolated channel belts. This stratigraphic trend is likely due to an upward decreasing sediment supply indicated by the shelf-edge progradation rate and channel size, as well as an upward increasing shelf accommodation indicated by the shelf-edge aggradation rate. The rapid shelf-edge progradation and large rivers in Sequence Sets B and C confirm earlier suggestions that it was the early phase of Lower Wilcox dispersal that brought the largest deep-water sediment volumes into the Gulf of Mexico. Key factors in this Lower Wilcox stratigraphic trend are likely to have been a very high initial sediment flux to the Gulf because of the high initial release of sediment from Laramide catchments to the north and northwest, possibly aided by modest eustatic sea-level fall on the Texas shelf, which is suggested by the early, flat shelf-edge trajectory, high amalgamation of channel belts, and the low overall aggradation rate of the Sequence Sets B and C.

The effect of a gearshift interlock on seat belt use by drivers who do not always use a belt and its acceptance among those who do.

PubMed

Kidd, David G; Singer, Jeremiah; Huey, Richard; Kerfoot, Laura

2018-06-01

Seat belts reduce the risk of fatal injury in a crash, yet in 2015, nearly 10,000 people killed in passenger vehicles were unrestrained. Enhanced seat belt reminders increase belt use, but a gearshift interlock that prevents the vehicle from being placed into gear unless the seat belt is used may prove more effective. Thirty-two people with a recent seat belt citation and who admitted to not always using a seat belt as a driver were recruited as part-time belt users and asked to evaluate two new vehicles. Sixteen drove two vehicles with an enhanced reminder for one week each, and 16 drove a vehicle with an enhanced reminder for one week and a vehicle with a gearshift interlock the following week. Sixteen full-time belt users who reported always using a seat belt drove a vehicle with a gearshift interlock for one week to evaluate acceptance. Relative to the enhanced reminder, the gearshift interlock significantly increased the likelihood that a part-time belt user used a belt during travel time in a trip by 21%, and increased the rate of belt use by 16%; this effect approached significance. Although every full-time belt user experienced the gearshift interlock, their acceptance of the technology reported in a post-study survey was fairly positive and not significantly different from part-time belt users. Six part-time belt users circumvented the gearshift interlock by sitting on a seat belt, waiting for the system to deactivate, or unbuckling during travel. The gearshift interlock increased the likelihood that part-time belt users buckled up and the rate of belt use during travel relative to the enhanced reminder but could be more effective if it prevented circumvention. An estimated 718-942 lives could be saved annually if the belt use of unbuckled drivers and front passengers increased 16-21%. Copyright © 2018 National Safety Council and Elsevier Ltd. All rights reserved.

Ultra-short beam expander with segmented curvature control: the emergence of a semi-lens

DOE PAGES

Abbaslou, Siamak; Gatdula, Robert; Lu, Ming; ...

2017-01-01

We introduce direct curvature control in designing a segmented beam expander, and explore novel design possibilities for ultra-compact beam expanders. Assisted by the particle swarm optimization algorithm, we search for an optimal curvature-controlled multi-segment taper that maintains width continuity. Counterintuitively, the optimization yields a structure with abrupt width discontinuity and width compression features. Through spatial phase and parameterized analysis, a semi-lens feature is revealed that helps to flatten the wavefront at the output end for higher coupling efficiency. Such functionality cannot be achieved by normal tapers in a short distance. The structure is fabricated and characterized experimentally. By a figuremore » of merit that accounts for expansion ratio, length, and efficiency, this structure outperforms an adiabatic taper by 9 times.« less

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

Campbell, John; Carena, Marcela; Harnik, Roni

We consider interference between the Higgs signal and QCD background inmore » $$gg\\rightarrow h \\rightarrow \\gamma\\gamma$$ and its effect on the on-shell Higgs rate. The existence of sizable strong phases leads to destructive interference of about 2% of the on-shell cross section in the Standard Model. This effect can be enhanced by beyond the standard model physics. In particular, since it scales differently from the usual rates, the presence of interference allows indirect limits to be placed on the Higgs width in a novel way, using on-shell rate measurements. Our study motivates further QCD calculations to reduce uncertainties. We discuss potential width-sensitive observables, both using total and differential rates and find that the HL-LHC can potentially indirectly probe widths of order tens of MeV.« less

Width-Tuned Magnetic Order Oscillation on Zigzag Edges of Honeycomb Nanoribbons.

PubMed

Chen, Wen-Chao; Zhou, Yuan; Yu, Shun-Li; Yin, Wei-Guo; Gong, Chang-De

2017-07-12

Quantum confinement and interference often generate exotic properties in nanostructures. One recent highlight is the experimental indication of a magnetic phase transition in zigzag-edged graphene nanoribbons at the critical ribbon width of about 7 nm [ Magda , G. Z. et al. Nature 2014 , 514 , 608 ]. Here we show theoretically that with further increase in the ribbon width, the magnetic correlation of the two edges can exhibit an intriguing oscillatory behavior between antiferromagnetic and ferromagnetic, driven by acquiring the positive coherence between the two edges to lower the free energy. The oscillation effect is readily tunable in applied magnetic fields. These novel properties suggest new experimental manifestation of the edge magnetic orders in graphene nanoribbons and enhance the hopes of graphene-like spintronic nanodevices functioning at room temperature.

The influence of dynamical friction and mean motion resonances on terrestrial planet growth

NASA Astrophysics Data System (ADS)

Wallace, Spencer Clark; Quinn, Thomas R.

2018-04-01

We present a set of high-resolution direct N-body simulations of planetesimal coagulation at 1 AU. We follow the evolution of of 1 million planetesimals in a ring though the runaway and oligarchic growth phases. During oligarchic growth, the size frequency distribution (SFD) of planetesimals develops a bump at intermediate masses, which we argue is due to dynamical friction acting through mean motion resonances, heating the low mass planetesimals and inhibiting their growth. This feature is similar to the bump seen in the SFD of asteroid belt and Kuiper belt objects and we argue that a careful treatment of the dynamics of planetesimal interactions is required in order to adequately explain the observed SFD. Although our model does not account for fragmentation, our results show that a similar feature can be produced without it, which is in contention with previous studies.

Impact of enhanced sensory input on treadmill step frequency: infants born with myelomeningocele.

PubMed

Pantall, Annette; Teulier, Caroline; Smith, Beth A; Moerchen, Victoria; Ulrich, Beverly D

2011-01-01

To determine the effect of enhanced sensory input on the step frequency of infants with myelomeningocele (MMC) when supported on a motorized treadmill. Twenty-seven infants aged 2 to 10 months with MMC lesions at, or caudal to, L1 participated. We supported infants upright on the treadmill for 2 sets of 6 trials, each 30 seconds long. Enhanced sensory inputs within each set were presented in random order and included baseline, visual flow, unloading, weights, Velcro, and friction. Overall friction and visual flow significantly increased step rate, particularly for the older subjects. Friction and Velcro increased stance-phase duration. Enhanced sensory input had minimal effect on leg activity when infants were not stepping. : Increased friction via Dycem and enhancing visual flow via a checkerboard pattern on the treadmill belt appear to be more effective than the traditional smooth black belt surface for eliciting stepping patterns in infants with MMC.

Impact of Enhanced Sensory Input on Treadmill Step Frequency: Infants Born With Myelomeningocele

PubMed Central

Pantall, Annette; Teulier, Caroline; Smith, Beth A; Moerchen, Victoria; Ulrich, Beverly D.

2012-01-01

Purpose To determine the effect of enhanced sensory input on the step frequency of infants with myelomeningocele (MMC) when supported on a motorized treadmill. Methods Twenty seven infants aged 2 to 10 months with MMC lesions at or caudal to L1 participated. We supported infants upright on the treadmill for 2 sets of 6 trials, each 30s long. Enhanced sensory inputs within each set were presented in random order and included: baseline, visual flow, unloading, weights, Velcro and friction. Results Overall friction and visual flow significantly increased step rate, particularly for the older group. Friction and Velcro increased stance phase duration. Enhanced sensory input had minimal effect on leg activity when infants were not stepping. Conclusions Increased friction via Dycem and enhancing visual flow via a checkerboard pattern on the treadmill belt appear more effective than the traditional smooth black belt surface for eliciting stepping patterns in infants with MMC. PMID:21266940

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

Mainzer, A.; Masiero, J.; Bauer, J.

Enhancements to the science data processing pipeline of NASA's Wide-field Infrared Survey Explorer (WISE) mission, collectively known as NEOWISE, resulted in the detection of >158,000 minor planets in four infrared wavelengths during the fully cryogenic portion of the mission. Following the depletion of its cryogen, NASA's Planetary Science Directorate funded a four-month extension to complete the survey of the inner edge of the Main Asteroid Belt and to detect and discover near-Earth objects (NEOs). This extended survey phase, known as the NEOWISE Post-Cryogenic Survey, resulted in the detection of {approx}6500 large Main Belt asteroids and 86 NEOs in its 3.4more » and 4.6 {mu}m channels. During the Post-Cryogenic Survey, NEOWISE discovered and detected a number of asteroids co-orbital with the Earth and Mars, including the first known Earth Trojan. We present preliminary thermal fits for these and other NEOs detected during the 3-Band Cryogenic and Post-Cryogenic Surveys.« less

Bursty Precipitation Driven by Chorus Waves

NASA Technical Reports Server (NTRS)

Khazanov, G. V.; Telnikhin, A. A.; Kronberg, T. K.

2011-01-01

The electron precipitation bursts have been shown to be a major sink for the radiation belt relativistic electrons. As underlying mechanism of such bursts, we propose particle scattering into the loss cone due to nonlinear resonance interaction between electrons and chorus. Stochastic heating due to the coupling leads to diffusion in pitch angle, and the rate of diffusion would be sufficient to account for the emptying of the Earth's radiation belt over the time of the main phase of geomagnetic storms. The results obtained in the present paper account for a strong energy dependence in the electron precipitation event and the correlation between the energization and loss processes on macroscopic timescales, which is primarily attributed to the cooperative effects of the coupling. This mechanism of chorus scattering should produce pitch angle distributions that are energy-dependent and butterfly-shaped. The calculated timescales and the total energy input to the atmosphere from precipitating relativistic electrons are in reasonable agreement with experimental data.

Shear zones bounding the central zone of the Limpopo Mobile Belt, southern Africa

NASA Astrophysics Data System (ADS)

McCouri, Stephen; Vearncombe, Julian R.

Contrary to previously suggested north-directed thrust emplacement of the central zone of the Limpopo mobile belt, we present evidence indicating west-directed emplacement. The central zone differs from the marginal zones in rock types, structural style and isotopic signature and is an allochthonous thrust sheet. It is bounded in the north by the dextral Tuli-Sabi shear zone and in the south by the sinistral Palala shear zone which are crustal-scale lateral ramps. Published gravity data suggest that the lateral ramps are linked at depth and they probably link at the surface, in a convex westward frontal ramp, in the vicinity of longitude 26°30'E in eastern Botswana. Two phases of movement, the first between 2.7 and 2.6 Ga and the second between 2.0 and 1.8 Ga. occurred on both the Tuli-Sabi and the Palala shear zones.

Comfort and convenience specifications for safety belts : shoulder belt fit, pressure and pullout forces

DOT National Transportation Integrated Search

1980-04-30

A three-part study was conducted to further define comfort requirements for seat belt systems with respect to shoulder belt fit, shoulder belt contact pressure, and 3-point restraint system pullout forces. Objective of the belt-fit portion of the stu...

The evolution of ring current ion energy density and energy content during geomagnetic storms based on Van Allen Probes measurements

DOE PAGES

Zhao, H.; Li, X.; Baker, D. N.; ...

2015-08-25

Enabled by the comprehensive measurements from the Magnetic Electron Ion Spectrometer (MagEIS), Helium Oxygen Proton Electron mass spectrometer (HOPE), and Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instruments onboard Van Allen Probes in the heart of the radiation belt, the relative contributions of ions with different energies and species to the ring current energy density and their dependence on the phases of geomagnetic storms are quantified. The results show that lower energy (<50 keV) protons enhance much more often and also decay much faster than higher-energy protons. During the storm main phase, ions with energies <50 keV contribute moremore » significantly to the ring current than those with higher energies; while the higher-energy protons dominate during the recovery phase and quiet times. The enhancements of higher-energy proton fluxes as well as energy content generally occur later than those of lower energy protons, which could be due to the inward radial diffusion. For the 29 March 2013 storm we investigated in detail that the contribution from O + is ~25% of the ring current energy content during the main phase and the majority of that comes from <50 keV O +. This indicates that even during moderate geomagnetic storms the ionosphere is still an important contributor to the ring current ions. Using the Dessler-Parker-Sckopke relation, the contributions of ring current particles to the magnetic field depression during this geomagnetic storm are also calculated. In conclusion, the results show that the measured ring current ions contribute about half of the Dst depression.« less

Sichuan Basin and beyond: Eastward foreland growth of the Tibetan Plateau from an integration of Late Cretaceous-Cenozoic fission track and (U-Th)/He ages of the eastern Tibetan Plateau, Qinling, and Daba Shan

NASA Astrophysics Data System (ADS)

Yang, Zhao; Shen, Chuanbo; Ratschbacher, Lothar; Enkelmann, Eva; Jonckheere, Raymond; Wauschkuhn, Bastian; Dong, Yunpeng

2017-06-01

Combining 121 new fission track and (U-Th)/He ages with published thermochronologic data, we investigate the Late Cretaceous-Cenozoic exhumation/cooling history of the eastern Tibetan Plateau, Qinling, Daba Shan, and Sichuan Basin of east central China. The Qinling orogen shows terminal southwestward foreland growth in the northern Daba Shan thrust belt at 100-90 Ma and in the southern Daba Shan fold belt at 85-70 Ma. The eastern margin of Tibetan Plateau experienced major exhumation phases at 70-40 Ma (exhumation rate 0.05-0.08 mm/yr), 25-15 Ma (≤1 mm/yr in the Pengguan Massif; 0.2 mm/yr in the imbricated western Sichuan Basin), and since 11-10 Ma along the Longmen Shan ( 0.80 mm/yr) and the interior of the eastern Tibetan Plateau (Dadu River gorge, Min Shan; 0.50 mm/yr). The Sichuan Basin records two basin-wide denudation phases, likely a result of the reorganization of the upper Yangtze River drainage system. The first phase commenced at 45 Ma and probably ended before the Miocene; >1 km of rocks were eroded from the central and eastern Sichuan Basin. The second phase commenced at 12 Ma and denudated the central Sichuan Basin, Longmen Shan, and southern Daba Shan; more than 2 km of rocks were eroded after the lower Yangtze River had cut through the Three Gorges and captured the Sichuan Basin drainage. In contrast to the East Qinling, which was weakly effected by late Cenozoic exhumation, the West Qinling and Daba Shan have experienced rapid exhumation/cooling since 15-13 Ma, a result of growth of the Tibetan Plateau beyond the Sichuan Basin.

Cenozoic intraplate tectonics in Central Patagonia: Record of main Andean phases in a weak upper plate

NASA Astrophysics Data System (ADS)

Gianni, G. M.; Echaurren, A.; Folguera, A.; Likerman, J.; Encinas, A.; García, H. P. A.; Dal Molin, C.; Valencia, V. A.

2017-11-01

Contraction in intraplate areas is still poorly understood relative to similar deformation at plate margins. In order to contribute to its comprehension, we study the Patagonian broken foreland (PBF) in South America whose evolution remains controversial. Time constraints of tectonic events and structural characterization of this belt are limited. Also, major causes of strain location in this orogen far from the plate margin are enigmatic. To unravel tectonic events, we studied the Cenozoic sedimentary record of the central sector of the Patagonian broken foreland (San Bernardo fold and thrust belt, 44°30‧S-46°S) and the Andes (Meseta de Chalia, 46°S) following an approach involving growth-strata detection, U-Pb geochronology and structural modeling. Additionally, we elaborate a high resolution analysis of the effective elastic thickness (Te) to examine the relation between intraplate contraction location and variations in lithospheric strength. The occurrence of Eocene growth-strata ( 44-40 Ma) suggests that contraction in the Andes and the Patagonian broken foreland was linked to the Incaic phase. Detection of synextensional deposits suggests that the broken foreland collapsed partially during Oligocene to early Miocene. During middle Miocene times, the Quechua contractional phase produced folding of Neogene volcanic rocks and olistostrome deposition at 17 Ma. Finally, the presented Te map shows that intraplate contraction related to Andean phases localized preferentially along weak lithospheric zones (Te < 15 km). Hence, the observed strain distribution in the PBF appears to be controlled by lateral variations in the lithospheric strength. Variations in this parameter could be related to thermo-mechanical weakening produced by intraplate rifting in Paleozoic-Mesozoic times.

The evolution of ring current ion energy density and energy content during geomagnetic storms based on Van Allen Probes measurements

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

Zhao, H.; Li, X.; Baker, D. N.

Enabled by the comprehensive measurements from the Magnetic Electron Ion Spectrometer (MagEIS), Helium Oxygen Proton Electron mass spectrometer (HOPE), and Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instruments onboard Van Allen Probes in the heart of the radiation belt, the relative contributions of ions with different energies and species to the ring current energy density and their dependence on the phases of geomagnetic storms are quantified. The results show that lower energy (<50 keV) protons enhance much more often and also decay much faster than higher-energy protons. During the storm main phase, ions with energies <50 keV contribute moremore » significantly to the ring current than those with higher energies; while the higher-energy protons dominate during the recovery phase and quiet times. The enhancements of higher-energy proton fluxes as well as energy content generally occur later than those of lower energy protons, which could be due to the inward radial diffusion. For the 29 March 2013 storm we investigated in detail that the contribution from O + is ~25% of the ring current energy content during the main phase and the majority of that comes from <50 keV O +. This indicates that even during moderate geomagnetic storms the ionosphere is still an important contributor to the ring current ions. Using the Dessler-Parker-Sckopke relation, the contributions of ring current particles to the magnetic field depression during this geomagnetic storm are also calculated. In conclusion, the results show that the measured ring current ions contribute about half of the Dst depression.« less

Structural and petrographic constraints on the stratigraphy of the Lapataia Formation, with implications for the tectonic evolution of the Fuegian Andes

NASA Astrophysics Data System (ADS)

Cao, Sebastián J.; Torres Carbonell, Pablo J.; Dimieri, Luis V.

2018-07-01

The structure of the Fuegian Andes central belt is characterized by a first phase of peak metamorphism and ductile deformation, followed by a brittle-ductile thrusting phase including juxtaposition of different (first phase) structural levels; both related to the closure and inversion of the Late Jurassic-Early Cretaceous Rocas Verdes basin. The second phase involved thrust sheets of pre-Jurassic basement, as well as Upper Jurassic and Lower Cretaceous units from the volcanic-sedimentary fill of the basin. Rock exposures in the Parque Nacional Tierra del Fuego reveal a diversity of metamorphic mineral assemblages, dynamic recrystallization grades and associated structures, evidencing a variety of protoliths and positions in the crust during their orogenic evolution. Among the units present in this sector, the Lapataia Formation portrays the higher metamorphic grade reported in the Argentine side of the Fuegian Andes, and since no precise radiometric ages have been established to date, its stratigraphic position remains a matter of debate: the discussion being whether it belongs to the pre-Jurassic basement, or the Upper Jurassic volcanic/volcaniclastic initial fill of the Rocas Verdes basin. The mapping and petrographic/microstructural study of the Lapataia Formation and those of undoubtedly Mesozoic age, allow to characterize the former as a group of rocks with great lithological affinity with the Upper Jurassic metamorphic rocks found elsewhere in the central belt of the Fuegian Andes. The main differences in metamorphic grade are indebted to its deformation at deeper crustal levels, but during the same stages than the Mesozoic rocks. Accordingly, we interpret the regional structure to be associated with the stacking of thrust sheets from different structural levels through the emplacement of a duplex system during the growth of the Fuegian Andes.

Determination of Effective Crossover Location and Dimensions for Branched Detonation in a Pulsed Detonation Engine

DTIC Science & Technology

2012-03-22

location is varied from the aft end of the detonation tube to the middle of the detonation tube while the crossover width is varied from 2.5 in to 0.5...the other end where the tube is connected to a source of fuel, oxidizer, and ignition .7 The engine cycle is divided into three equal phases: fill...location and width of the crossover duct for hydrogen, ethylene and an n-alkane. The crossover location is varied from the aft end of the

Seismic geomorphology of the Lobed-channel System of Upper Miocene Huangliu Formation, Yinggehai Basin, Northwestern South China Sea

NASA Astrophysics Data System (ADS)

Liu, H.

2016-02-01

Three-dimensional seismic data have been widely used in interpreting ancient river systems and their associated sediment deposits. Thin-bed reservoirs of lobed-channel system in lithostratigraphic units of Dongfang (DF) area are one of the major study areas for reservoir growth in the Yinggehai basin of northwestern South China Sea. Although it is understood that the transport mechanics of parent substrate and alluvium determine the morphology of channel for lobed-channel system, the transport mechanism and regional gradient are relatively poorly understood. This study is focused on the application of various techniques in seismic geomorphology to the Yinggehai Basin at paleo-water-depth of 120m to assess influences of regional gradient and relative sea level change on lobed-channel palaeogeomorphology in shallow-water environments. The Vietnam paleo-Blue River, which located at south of modern Red River, flowed through DF area and transported turbidity deposit to DF area in the coastal environment. In 3-D seismic survey area, four fifth-order sequences in first member of upper Miocene Huangliu formation were identified using well and seismic data. Seismic inversion and 90° phasing of seismic data were used to convert seismic traces to pseudolithologic logs. Stratal slicing made it possible to interpolate and extrapolate well-data-derived sequence and identify submarine fan, channel fill, lobes and overbank deposit. Strata slices suggested that sea-floor slopes exerted main influence on channel morphology. Specifically, DF13-1 block had high gradient, which mainly distributed mud-sand-rich lobes. However, DF13-2 block established low gradient, which mostly indicated sand-rich braided channels. The values of sinuosity, channel widths, meander-belt widths in DF13-2 block are all greater than these in DF13-1 block. In addition, results of carbon isotope measurements and foraminiferal research of two blocks suggest that paleo sea level in DF13-2 block (30m 150m) was higher than that of DF13-1 block (20m 90m). It also deciphered why channels in DF13-2 incised deeply because of the stronger hydrodynamic energy in the shallow-water environments. Thus DF13-2 block was formed in a lobed-channel and sand rich system, compared with DF13-1 of channelized-lobes and mud-sand rich system.