The effect of anisotropic heat transport on magnetic islands in 3-D configurations

NASA Astrophysics Data System (ADS)

Schlutt, M. G.; Hegna, C. C.

2012-08-01

An analytic theory of nonlinear pressure-induced magnetic island formation using a boundary layer analysis is presented. This theory extends previous work by including the effects of finite parallel heat transport and is applicable to general three dimensional magnetic configurations. In this work, particular attention is paid to the role of finite parallel heat conduction in the context of pressure-induced island physics. It is found that localized currents that require self-consistent deformation of the pressure profile, such as resistive interchange and bootstrap currents, are attenuated by finite parallel heat conduction when the magnetic islands are sufficiently small. However, these anisotropic effects do not change saturated island widths caused by Pfirsch-Schlüter current effects. Implications for finite pressure-induced island healing are discussed.

The portals 4.0.1 network programming interface.

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

Barrett, Brian W.; Brightwell, Ronald Brian; Pedretti, Kevin

2013-04-01

This report presents a specification for the Portals 4.0 network programming interface. Portals 4.0 is intended to allow scalable, high-performance network communication between nodes of a parallel computing system. Portals 4.0 is well suited to massively parallel processing and embedded systems. Portals 4.0 represents an adaption of the data movement layer developed for massively parallel processing platforms, such as the 4500-node Intel TeraFLOPS machine. Sandias Cplant cluster project motivated the development of Version 3.0, which was later extended to Version 3.3 as part of the Cray Red Storm machine and XT line. Version 4.0 is targeted to the next generationmore » of machines employing advanced network interface architectures that support enhanced offload capabilities. 3« less

Morphological characterization of rat entorhinal neurons in vivo: soma-dendritic structure and axonal domains.

PubMed

Lingenhöhl, K; Finch, D M

1991-01-01

We used in vivo intracellular labeling with horseradish peroxidase in order to study the soma-dendritic morphology and axonal projections of rat entorhinal neurons. The cells responded to hippocampal stimulation with inhibitory postsynaptic potentials, and thus likely received direct or indirect hippocampal input. All cells (n = 24) showed extensive dendritic domains that extended in some cases for more than 1 mm. The dendrites of layer II neurons were largely restricted to layers I and II or layers I-III, while the dendrites of deeper cells could extend through all cortical layers. Computed 3D rotations showed that the basilar dendrites of deep pyramids extended roughly parallel to the cortical layering, and that they were mostly confined to the layer containing the soma and layers immediately adjacent. Total dendritic lengths averaged 9.8 mm +/- 3.8 (SD), and ranged from 5 mm to more than 18 mm. Axonal processes could be visualized in 21 cells. Most of these showed axonal branching within the entorhinal cortex, sometimes extensive. Efferent axonal domains were reconstructed in detail in 3 layer II stellate cells. All 3 projected axons across the subicular complex to the dentate gyrus. One of these cells showed an extensive net-like axonal domain that also projected to several other structures, including the hippocampus proper, subicular complex, and the amygdalo-piriform transition area. The axons of layer III and IV cells projected to the angular bundle, where they continued in a rostral direction. In contrast to the layer II, III and IV cells, no efferent axonal branches leaving the entorhinal cortex could be visualized in 5 layer V neurons. The data indicate that entorhinal neurons can integrate input from a considerable volume of entorhinal cortex by virtue of their extensive dendritic domains, and provide a further basis for specifying the layers in which cells receive synaptic input. The extensive axonal branching pattern seen in most of the cells would support divergent propagation of their activity.

Exploration of ground instability factor causing slumping and related dewatering in high methane-flux and gentle continental slope off Shimokita Peninsula, NE Japan

NASA Astrophysics Data System (ADS)

Morita, S.; Nakajima, T.; Goto, S.; Yamada, Y.; Kawamura, K.

2012-12-01

A great number of slump (submarine landslide) units have been identified by reflection seismic surveys performed off Shimokita Peninsula, NE Japan (Morita, et al., 2011). A 3-D seismic data revealed typical deformations caused by slumping and related dewatering in the Pliocene and upper formations. The slumping was generated primarily by layer-parallel slip in a very gentle (<1 degree) and flat continental slope. The size of slump units extends over 30 km in both width and slip direction in maximum. The slump units often exhibit an imbrication structure formed by repeated thrusting in the bottom layers, being mostly composed of the thrust blocks and little matrix. The dewatering structure is observed as widespread parallel dikes of which distribution is strongly dependent on the imbrication of the slump units. Slip planes of the slumps are traceable in seismic data because of the layer-parallel slip. The layers which correspond to the slip planes proved to be generally characterized as low-amplitude layers having some thickness, and some of the slip planes exhibit flattened features under the slump units of the imbrication structure accompanied by parallel dikes. This implies that excess fluid in the slip plane caused the lubrication to enhance the slumping and was drained through the parallel dikes during slumping. Some typical structures related to natural gas, e.g. enhanced reflection, gas chimney, have been identified in the seismic data. The shakedown cruise of D/V Chikyu in 2006 reported a recovery of gas hydrate in nearby area (Higuchi et al., 2009). A shallow sulfate-methane interface (SMI) of 3.5-12 mbsf has been reported in the survey area (Kotani et al., 2007). These features indicate that a high methane flux in the area is likely an important ground instability factor to cause the slumping and the dewatering phenomena. We recognize that the set of the slump units in the survey area is one of the most suitable targets to approach mechanism of submarine landslides so that we started exploring the feasibility of a scientific drilling in this survey area.

Extended surface parallel coating inspection method

DOEpatents

Naulleau, Patrick P.

2006-03-21

Techniques for rapidly characterizing reflective surfaces and especially multi-layer EUV reflective surfaces of optical components involve illuminating the entire reflective surface instantaneously and detecting the image far field. The technique provides a mapping of points on the reflective surface to corresponding points on a detector, e.g., CCD. This obviates the need to scan a probe over the entire surface of the optical component. The reflective surface can be flat, convex, or concave.

Three d10 coordination polymers assembled from 3,5-bis(imidazole-1-yl)pyridine and different polycarboxylates: Syntheses, structures and luminescence properties

NASA Astrophysics Data System (ADS)

Pan, Jie; Zhang, Di; Xue, Zhen-Zhen; Wei, Li; Han, Song-De; Wang, Guo-Ming

2017-11-01

Three novel Zn(II)/Cd(II) coordination polymers, [Cd2(bip)2(m-bdc)2(H2O)2·3H2O]n (1), [Zn2(bip)2(p-bdc)2·2.5H2O]n (2) and [Zn(bip) (p-bdc)·3H2O]n (3), where bip = 3,5-bis(imidazole-1-yl)pyridine, m-H2bdc = 1,3-benzenedicarboxylic acid, p-H2bdc = 1,4-benzenedicarboxylic acid, have been successfully synthesized under solvothermal conditions. The linkage of different ligands with Cd(II) ions in compound 1 affords a (3,5)-connected layer. Furthermore, 2D→3D parallel polycatenation occurs wherein the layers are polycatenated with the adjacent two parallel layers to form a 3D framework. In 2 and 3, the polycarboxylates act as pillars to combine the metal-bip chains, yielding the layered structures. These 2D networks are extended to the final 3D supramolecular architectures by π-π stacking interactions. The results show that bip can act as a versatile building block for the construction of various coordination polymers. Moreover, the fluorescent properties of 1-3 in the solid state at room temperature have been investigated.

Distribution of blocking temperatures in nano-oxide layers of specular spin valves

NASA Astrophysics Data System (ADS)

Ventura, J.; Araujo, J. P.; Sousa, J. B.; Veloso, A.; Freitas, P. P.

2007-06-01

Specular spin valves show enhanced giant magnetoresistive (GMR) ratio when compared to other, simpler, spin valve structures. The enhancement of GMR results from specular reflection in nano-oxide layers (NOLs) formed by the partial oxidation of the pinned and free layer. These oxides forming the NOL order antiferromagnetically (AFM) below a temperature T ˜175 K. Here, we study the effects of the pinned layer magnetization and its domain structure on the AFM ordering of the NOL by performing field cooling measurements with different cooling fields (H0). We observe enhanced (reduced) exchange field and magnetoresistive ratio for H0>0(<0), i.e., parallel (antiparallel) to the pinned magnetization. These measurements allowed us to confirm the existence of a wide distribution of blocking temperatures (TB) in the NOL of specular spin valves, having a maximum at T ≈175 K, and extending to NOL regions with TB as low as 15 K.

Passively cooled direct drive wind turbine

DOEpatents

Costin, Daniel P [Chelsea, VT

2008-03-18

A wind turbine is provided that passively cools an electrical generator. The wind turbine includes a plurality of fins arranged peripherally around a generator house. Each of the fins being oriented at an angle greater than zero degrees to allow parallel flow of air over the fin. The fin is further tapered to allow a constant portion of the fin to extend beyond the air stream boundary layer. Turbulence initiators on the nose cone further enhance heat transfer at the fins.

Crystal structure of catena-poly[N,N,N′,N′-tetra­methyl­guanidinium [(chlorido­cadmate)-di-μ-chlorido

PubMed Central

Ndiaye, Mamadou; Samb, Abdoulaye; Diop, Libasse; Maris, Thierry

2016-01-01

In the structure of the title salt, {(C5H14N3)[CdCl3]}n, the CdII atom of the complex anion is five-coordinated by one terminal and four bridging Cl atoms. The corresponding coordination polyhedron is a distorted trigonal bipyramid, with Cd—Cl distances in the range 2.4829 (4)–2.6402 (4) Å. The bipyramids are condensed into a polyanionic zigzag chain extending parallel to [101]. The tetra­methyl­guanidinium cations are situated between the polyanionic chains and are linked to them through N—H⋯Cl hydrogen bonds, forming a layered network parallel to (010). PMID:26870572

Full-f version of GENE for turbulence in open-field-line systems

NASA Astrophysics Data System (ADS)

Pan, Q.; Told, D.; Shi, E. L.; Hammett, G. W.; Jenko, F.

2018-06-01

Unique properties of plasmas in the tokamak edge, such as large amplitude fluctuations and plasma-wall interactions in the open-field-line regions, require major modifications of existing gyrokinetic codes originally designed for simulating core turbulence. To this end, the global version of the 3D2V gyrokinetic code GENE, so far employing a δf-splitting technique, is extended to simulate electrostatic turbulence in straight open-field-line systems. The major extensions are the inclusion of the velocity-space nonlinearity, the development of a conducting-sheath boundary, and the implementation of the Lenard-Bernstein collision operator. With these developments, the code can be run as a full-f code and can handle particle loss to and reflection from the wall. The extended code is applied to modeling turbulence in the Large Plasma Device (LAPD), with a reduced mass ratio and a much lower collisionality. Similar to turbulence in a tokamak scrape-off layer, LAPD turbulence involves collisions, parallel streaming, cross-field turbulent transport with steep profiles, and particle loss at the parallel boundary.

Re-Innovating Recycling for Turbulent Boundary Layer Simulations

NASA Astrophysics Data System (ADS)

Ruan, Joseph; Blanquart, Guillaume

2017-11-01

Historically, turbulent boundary layers along a flat plate have been expensive to simulate numerically, in part due to the difficulty of initializing the inflow with ``realistic'' turbulence, but also due to boundary layer growth. The former has been resolved in several ways, primarily dedicating a region of at least 10 boundary layer thicknesses in width to rescale and recycle flow or by extending the region far enough downstream to allow a laminar flow to develop into turbulence. Both of these methods are relatively costly. We propose a new method to remove the need for an inflow region, thus reducing computational costs significantly. Leveraging the scale similarity of the mean flow profiles, we introduce a coordinate transformation so that the boundary layer problem can be solved as a parallel flow problem with additional source terms. The solutions in the new coordinate system are statistically homogeneous in the downstream direction and so the problem can be solved with periodic boundary conditions. The present study shows the stability of this method, its implementation and its validation for a few laminar and turbulent boundary layer cases.

Poly[di-μ2-chlorido-tri-μ2-terephthalato-tetra­lead(II)

PubMed Central

Yang, Lei; Li, Zhongyue; Li, Guanghua

2011-01-01

The title compound, [Pb4(C8H4O4)3Cl2]n, consists of a three-dimensional inorganic–organic hybrid framework. The asymmetric unit contains two Pb2+ cations, one Cl− anion and one and a half terephthalate anions, the latter being completed by inversion symmetry. The two Pb2+ cations are each surrounded by five O atoms and one Cl atom in the form of irregular polyhedra. The cations are linked by μ2-O and μ2-Cl atoms into binuclear units, which are further extended through Pb—O inter­actions into an undulated inorganic layer parallel to (001). These layers are connected along [001] by the terephthalate groups into a three-dimensional framework. PMID:21754648

Method and system to facilitate sealing in gas turbines

DOEpatents

Morgan, Victor John; Foster, Gregory Thomas; Sarawate, Neelesh Nandkumar

2017-09-12

A method and system for sealing between components within a gas turbine is provided. A first recess defined in a first component receives a seal member. A second recess defined in a second component adjacent the first component also receives the seal member. The first and second recesses are located proximate a hot gas path defined through the gas turbine, and define circumferential paths about the turbine axis. The seal member includes a sealing face that extends in a direction substantially parallel to the turbine axis. The seal member also includes a plurality of seal layers, wherein at least one of the seal layers includes at least one stress relief region for facilitating flexing of the first seal member.

Equilibrium structure of the plasma sheet boundary layer-lobe interface

NASA Technical Reports Server (NTRS)

Romero, H.; Ganguli, G.; Palmadesso, P.; Dusenbery, P. B.

1990-01-01

Observations are presented which show that plasma parameters vary on a scale length smaller than the ion gyroradius at the interface between the plasma sheet boundary layer and the lobe. The Vlasov equation is used to investigate the properties of such a boundary layer. The existence, at the interface, of a density gradient whose scale length is smaller than the ion gyroradius implies that an electrostatic potential is established in order to maintain quasi-neutrality. Strongly sheared (scale lengths smaller than the ion gyroradius) perpendicular and parallel (to the ambient magnetic field) electron flows develop whose peak velocities are on the order of the electron thermal speed and which carry a net current. The free energy of the sheared flows can give rise to a broadband spectrum of electrostatic instabilities starting near the electron plasma frequency and extending below the lower hybrid frequency.

3D H-bonding networks self-assembly from pyridinium derivatives and bis(maleonitriledithiolato)zincate(II)

NASA Astrophysics Data System (ADS)

Ren, Xiaoming; Xie, Jingli; Chen, Youcun; Kremer, Reinhard Karl

2003-11-01

The two ion-pair complexes, [pyH] 2[Zn(mnt) 2] ( 1) and [4,4'-bipyH 2]-[Zn(mnt) 2] ( 2), were synthesized, where mnt 2- denotes maleonitriledithiolate, and [pyH] +, [4,4'-bipyH 2] 2+ represent pyridinium and diprotonated 4,4'-bipyridinium, respectively. Their single crystal structures show that there are strong bifurcated H-bonding interactions between the cations of the pyridinium derivative and the [Zn(mnt) 2] 2- anions in both 1 and 2. The bifurcated H-bonding interactions between the N-H of the pyridiniums and the CN groups of the mnt 2- ligands give rise to a 2D layered H-bonding network, the adjacent layers come together in such way as mutual embrace to give a tight pack, thus 2D hydrogen-bonding sheets further develop into 3D H-bonding networks through weak C-H⋯S and π⋯π stacking interactions in 1. As for 2, the cations and anions connect into several types of H-bonding macrorings ([2+2], [3+3] and [4+4]), these H-bonding macrorings fuse to extend into 2D layered structure, the interpenetration between [3+3] and [4+4] type H-bonding macrorings in the adjacent layers give further rise to novel 3D extended H-bonding networks, in which there are clearly parallel stacks of cations and the chelate rings of anions.

Transient Growth Analysis of Compressible Boundary Layers with Parabolized Stability Equations

NASA Technical Reports Server (NTRS)

Paredes, Pedro; Choudhari, Meelan M.; Li, Fei; Chang, Chau-Lyan

2016-01-01

The linear form of parabolized linear stability equations (PSE) is used in a variational approach to extend the previous body of results for the optimal, non-modal disturbance growth in boundary layer flows. This methodology includes the non-parallel effects associated with the spatial development of boundary layer flows. As noted in literature, the optimal initial disturbances correspond to steady counter-rotating stream-wise vortices, which subsequently lead to the formation of stream-wise-elongated structures, i.e., streaks, via a lift-up effect. The parameter space for optimal growth is extended to the hypersonic Mach number regime without any high enthalpy effects, and the effect of wall cooling is studied with particular emphasis on the role of the initial disturbance location and the value of the span-wise wavenumber that leads to the maximum energy growth up to a specified location. Unlike previous predictions that used a basic state obtained from a self-similar solution to the boundary layer equations, mean flow solutions based on the full Navier-Stokes (NS) equations are used in select cases to help account for the viscous-inviscid interaction near the leading edge of the plate and also for the weak shock wave emanating from that region. These differences in the base flow lead to an increasing reduction with Mach number in the magnitude of optimal growth relative to the predictions based on self-similar mean-flow approximation. Finally, the maximum optimal energy gain for the favorable pressure gradient boundary layer near a planar stagnation point is found to be substantially weaker than that in a zero pressure gradient Blasius boundary layer.

Observation of layered antiferromagnetism in self-assembled parallel NiSi nanowire arrays on Si(110) by spin-polarized scanning tunneling spectromicroscopy

NASA Astrophysics Data System (ADS)

Hong, Ie-Hong; Hsu, Hsin-Zan

2018-03-01

The layered antiferromagnetism of parallel nanowire (NW) arrays self-assembled on Si(110) have been observed at room temperature by direct imaging of both the topographies and magnetic domains using spin-polarized scanning tunneling microscopy/spectroscopy (SP-STM/STS). The topographic STM images reveal that the self-assembled unidirectional and parallel NiSi NWs grow into the Si(110) substrate along the [\\bar{1}10] direction (i.e. the endotaxial growth) and exhibit multiple-layer growth. The spatially-resolved SP-STS maps show that these parallel NiSi NWs of different heights produce two opposite magnetic domains, depending on the heights of either even or odd layers in the layer stack of the NiSi NWs. This layer-wise antiferromagnetic structure can be attributed to an antiferromagnetic interlayer exchange coupling between the adjacent layers in the multiple-layer NiSi NW with a B2 (CsCl-type) crystal structure. Such an endotaxial heterostructure of parallel magnetic NiSi NW arrays with a layered antiferromagnetic ordering in Si(110) provides a new and important perspective for the development of novel Si-based spintronic nanodevices.

Origin of Lamellar Magnetism (Invited)

NASA Astrophysics Data System (ADS)

McEnroe, S. A.; Robinson, P.; Fabian, K.; Harrison, R. J.

2010-12-01

The theory of lamellar magnetism arose through search for the origin of the strong and extremely stable remanent magnetization (MDF>100 mT) recorded in igneous and metamorphic rocks containing ilmenite with exsolution lamellae of hematite, or hematite with exsolution lamellae of ilmenite. Properties of rocks producing major remanent magnetic anomalies could not be explained by PM ilmenite or CAF hematite alone. Monte Carlo modeling of chemical and magnetic interactions in such intergrowths at high temperature indicated the presence of "contact layers" one cation layer thick at (001) interfaces of the two phases. Contact layers, with chemical composition different from layers in the adjacent phases, provide partial relief of ionic charge imbalance at interfaces, and can be common, not only in magnetic minerals. In rhombohedral Fe-Ti oxides, magnetic moments of 2 Fe2+Fe3+ contact layers (2 x 4.5µB) on both sides of a lamella, are balanced by the unbalanced magnetic moment of 1 Fe3+ hematite layer (1 x 5µB), to produce a net uncompensated ferrimagnetic "lamellar moment" of 4µB. Bulk lamellar moment is not proportional to the amount of magnetic oxide, but to the quantity of magnetically "in-phase" lamellar interfaces, with greater abundance and smaller thickness of lamellae, extending down to 1-2 nm. The proportion of "magnetically in-phase" lamellae relates to the orientation of (001) interfaces to the magnetizing field during exsolution, hence highest in samples with a strong lattice-preferred orientation of (001) parallel to the field during exsolution. The nature of contact layers, ~0.23 nm thick, with Fe2+Fe3+ charge ordering postulated by the Monte Carlo models, was confirmed by bond-valence and DFT calculations, and, their presence confirmed by Mössbauer measurements. Hysteresis experiments on hematite with nanoscale ilmenite at temperatures below 57 K, where ilmenite becomes AF, demonstrate magnetic exchange bias produced by strong coupling across phase interfaces. Interface coupling, with nominal magnetic moments perpendicular and parallel to (001), is facilitated by magnetic moments in hematite near interfaces that are a few degrees out of the (001) plane, proved by neutron diffraction experiments. When a ~b.y.-old sample, with a highly stable NRM, is ZF cooled below 57 K, it shows bimodal exchange bias, indicating the presence of two lamellar populations that are magnetically "out-of-phase", and incidentally proving the existence of lamellar magnetism. Lamellar magnetism may enhance the strength and stability of remanence in samples with magnetite or maghemite lamellae in pure hematite, or magnetite lamellae in ilmenite, where coarse magnetite or maghemite alone would be multi-domain. Here the "contact layers" should be a complex hybrid of 2/3-filled rhombohedral layers parallel to (001) and 3/4-filled cubic octahedral layers parallel to (111), with a common octahedral orientation confirmed by TEM observations. Here, because of different layer populations, the calculated lamellar moment may be higher than in the purely rhombohedral example.

Spectacular Layers Exposed in Becquerel Crater

NASA Technical Reports Server (NTRS)

2001-01-01

Toward the end of its Primary Mapping Mission, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) acquired one of its most spectacular pictures of layered sedimentary rock exposed within the ancient crater Becquerel. Pictures such as this one from January 25, 2001, underscore the fact that you never know from one day to the next what the next MOC images will uncover. While the Primary Mission ends January 31, 2001, thousands of new pictures--revealing as-yet-unseen terrain on the red planet--may be obtained during the Extended Mission phase, scheduled to run through at least April 2002.

The picture shown here reveals hundreds of light-toned layers in the 167 kilometers (104 miles) wide basin named for 19th Century French physicist Antoine H. Becquerel (1852-1908). These layers are interpreted to be sedimentary rocks deposited in the crater at some time in the distant past. They have since been eroded and exposed, revealing faults, dark layers between the bright layers, and a long geologic history (of unknown duration) recorded in these materials. Sets of parallel faults can be seen cutting across the layers in the left third of the image. Sunlight illuminates this scene from the top/upper right.

A second polymorph of catena-poly[[(1,10-phenanthroline-κ2 N,N′)copper(II)]-di-μ-thio­cyanato-κ2 N:S;κ2 S:N

PubMed Central

Zhang, Shi-Shen; Chen, Li-Jiang; Han, Yi-Feng

2011-01-01

In the title coordination polymer, [Cu(NCS)2(C12H8N2)]n, the CuII atom is situated on a twofold rotation axis and is coordinated by two N atoms from the bidentate 1,10-phenanthroline ligand and four thio­cyanate groups to confer a CuN4S2 octa­hedral geometry and resulting in a layer structure extending parallel to (100). PMID:21753934

Ideal magnetohydrodynamic theory for localized interchange modes in toroidal anisotropic plasmas

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

Shi, Tonghui, E-mail: thshi@ipp.ac.cn; Wan, B. N.; Sun, Y.

2016-08-15

Ideal magnetohydrodynamic theory for localized interchange modes is developed for toroidal plasmas with anisotropic pressure. The work extends the existing theories of Johnson and Hastie [Phys. Fluids 31, 1609 (1988)], etc., to the low n mode case, where n is the toroidal mode number. Also, the plasma compressibility is included, so that the coupling of the parallel motion to perpendicular one, i.e., the so-called apparent mass effect, is investigated in the anisotropic pressure case. The singular layer equation is obtained, and the generalized Mercier's criterion is derived.

An asymptotic analysis of supersonic reacting mixing layers

NASA Technical Reports Server (NTRS)

Jackson, T. L.; Hussaini, M. Y.

1987-01-01

The purpose of this paper is to present an asymptotic analysis of the laminar mixing of the simultaneous chemical reaction between parallel supersonic streams of two reacting species. The study is based on a one-step irreversible Arrhenius reaction and on large activation energy asymptotics. Essentially it extends the work of Linan and Crespo to include the effect of free shear and Mach number on the ignition regime, the deflagration regime and the diffusion flame regime. It is found that the effective parameter is the product of the characteristic Mach number and a shear parameter.

Beam forming network

NASA Technical Reports Server (NTRS)

Cramer, P. W., Jr. (Inventor)

1985-01-01

The network, which is connected to a layer of 134 feed elements that transmit and receive microwaves, consists of a pair of circuit boards parallel to the feed element layer. One of the two boards has 87 dividers that each divide a signal to be transmitted into seven portions, and the other board has 134 combiners that each collect seven transmit signal portions and deliver the sum to one of the feed elements. A similar arrangement is used to handle received signals. The large number of interconnections are made by printed circuit conductors radiating from each of the numerous dividers and combiners, and by providing interconnection pins that interconnect the ends of pairs of conductors lying on the two boards. The printed circuit conductors extend in undulating paths that provide maximum separation of conductors to minimize crosstalk.

Poly[[tetra-μ3-acetato-hexa-μ2-acetato­diaqua-μ2-oxalato-tetra­lanthanum(III)] dihydrate

PubMed Central

Di, Wen-Jing; Lan, Shao-Min; Zhang, Qun; Liang, Yun-Xiao

2011-01-01

The title compound, {[La4(CH3CO2)10(C2O4)(H2O)2]·2H2O}n, exhibits a two-dimensional layered structure with the oxalate and acetate ligands acting as bridges. The asymmetric unit contains two crystallographically independent lanthanum(III) ions, half of an oxalate ligand, five acetate ligands, one coordinated water mol­ecule and one uncoordinated water mol­ecule. The coordination numbers of the two La ions are 9 and 10. Adjacent layers of the structure, which extend parallel to (100), are linked by O–H⋯O hydrogen bonds and are also held together by van der Waals inter­actions between the CH3 groups of the acetate anions. PMID:22064832

Generic accelerated sequence alignment in SeqAn using vectorization and multi-threading.

PubMed

Rahn, René; Budach, Stefan; Costanza, Pascal; Ehrhardt, Marcel; Hancox, Jonny; Reinert, Knut

2018-05-03

Pairwise sequence alignment is undoubtedly a central tool in many bioinformatics analyses. In this paper, we present a generically accelerated module for pairwise sequence alignments applicable for a broad range of applications. In our module, we unified the standard dynamic programming kernel used for pairwise sequence alignments and extended it with a generalized inter-sequence vectorization layout, such that many alignments can be computed simultaneously by exploiting SIMD (Single Instruction Multiple Data) instructions of modern processors. We then extended the module by adding two layers of thread-level parallelization, where we a) distribute many independent alignments on multiple threads and b) inherently parallelize a single alignment computation using a work stealing approach producing a dynamic wavefront progressing along the minor diagonal. We evaluated our alignment vectorization and parallelization on different processors, including the newest Intel® Xeon® (Skylake) and Intel® Xeon Phi™ (KNL) processors, and use cases. The instruction set AVX512-BW (Byte and Word), available on Skylake processors, can genuinely improve the performance of vectorized alignments. We could run single alignments 1600 times faster on the Xeon Phi™ and 1400 times faster on the Xeon® than executing them with our previous sequential alignment module. The module is programmed in C++ using the SeqAn (Reinert et al., 2017) library and distributed with version 2.4. under the BSD license. We support SSE4, AVX2, AVX512 instructions and included UME::SIMD, a SIMD-instruction wrapper library, to extend our module for further instruction sets. We thoroughly test all alignment components with all major C++ compilers on various platforms. rene.rahn@fu-berlin.de.

Turbine vane structure

DOEpatents

Irwin, John A.

1980-08-19

A liquid cooled stator blade assembly for a gas turbine engine includes an outer shroud having a pair of liquid inlets and a pair of liquid outlets supplied through a header and wherein means including tubes support the header radially outwardly of the shroud and also couple the header with the pair of liquid inlets and outlets. A pair of turbine vanes extend radially between the shroud and a vane platform to define a gas turbine motive fluid passage therebetween; and each of the vanes is cooled by an internal body casting of super alloy material with a grooved layer of highly heat conductive material that includes spaced apart flat surface trailing edges in alignment with a flat trailing edge of the casting joined to wall segments of the liner which are juxtaposed with respect to the internal casting to form an array of parallel liquid inlet passages on one side of the vane and a second plurality of parallel liquid return passages on the opposite side of the vane; and a superalloy heat and wear resistant imperforate skin covers the outer surface of the composite blade including the internal casting and the heat conductive layer; a separate trailing edge section includes an internal casting and an outer skin butt connected to the end surfaces of the internal casting and the heat conductive layer to form an easily assembled liquid cooled trailing edge section in the turbine vane.

Ca(5)Zr(3)F(22).

PubMed

Oudahmane, Abdelghani; El-Ghozzi, Malika; Avignant, Daniel

2012-04-01

Single crystals of Ca(5)Zr(3)F(22), penta-calcium trizirconium docosafluoride, were obtained unexpectedly by solid-state reaction between CaF(2) and ZrF(4) in the presence of AgF. The structure of the title compound is isotypic with that of Sr(5)Zr(3)F(22) and can be described as being composed of layers with composition [Zr(3)F(20)](8-) made up from two different [ZrF(8)](4-) square anti-prisms (one with site symmetry 2) by corner-sharing. The layers extending parallel to the (001) plane are further linked by Ca(2+) cations, forming a three-dimensional network. Amongst the four crystallographically different Ca(2+) ions, three are located on twofold rotation axes. The Ca(2+) ions exhibit coordination numbers ranging from 8 to 12, depending on the cut off, with very distorted fluorine environments. Two of the Ca(2+) ions occupy inter-stices between the layers whereas the other two are located in void spaces of the [Zr(3)F(20)](8-) layer and alternate with the two Zr atoms along [010]. The crystal under investigation was an inversion twin.

Gilgamesh: A Multithreaded Processor-In-Memory Architecture for Petaflops Computing

NASA Technical Reports Server (NTRS)

Sterling, T. L.; Zima, H. P.

2002-01-01

Processor-in-Memory (PIM) architectures avoid the von Neumann bottleneck in conventional machines by integrating high-density DRAM and CMOS logic on the same chip. Parallel systems based on this new technology are expected to provide higher scalability, adaptability, robustness, fault tolerance and lower power consumption than current MPPs or commodity clusters. In this paper we describe the design of Gilgamesh, a PIM-based massively parallel architecture, and elements of its execution model. Gilgamesh extends existing PIM capabilities by incorporating advanced mechanisms for virtualizing tasks and data and providing adaptive resource management for load balancing and latency tolerance. The Gilgamesh execution model is based on macroservers, a middleware layer which supports object-based runtime management of data and threads allowing explicit and dynamic control of locality and load balancing. The paper concludes with a discussion of related research activities and an outlook to future work.

Carbon nanotube-based three-dimensional monolithic optoelectronic integrated system

NASA Astrophysics Data System (ADS)

Liu, Yang; Wang, Sheng; Liu, Huaping; Peng, Lian-Mao

2017-06-01

Single material-based monolithic optoelectronic integration with complementary metal oxide semiconductor-compatible signal processing circuits is one of the most pursued approaches in the post-Moore era to realize rapid data communication and functional diversification in a limited three-dimensional space. Here, we report an electrically driven carbon nanotube-based on-chip three-dimensional optoelectronic integrated circuit. We demonstrate that photovoltaic receivers, electrically driven transmitters and on-chip electronic circuits can all be fabricated using carbon nanotubes via a complementary metal oxide semiconductor-compatible low-temperature process, providing a seamless integration platform for realizing monolithic three-dimensional optoelectronic integrated circuits with diversified functionality such as the heterogeneous AND gates. These circuits can be vertically scaled down to sub-30 nm and operates in photovoltaic mode at room temperature. Parallel optical communication between functional layers, for example, bottom-layer digital circuits and top-layer memory, has been demonstrated by mapping data using a 2 × 2 transmitter/receiver array, which could be extended as the next generation energy-efficient signal processing paradigm.

Physical and technological principles of designing layer-gradient multicomponent surfaces by combining the methods of ion-diffusion saturation and magnetron- and vacuum-arc deposition

NASA Astrophysics Data System (ADS)

Savostikov, V. M.; Potekaev, A. I.; Tabachenko, A. N.

2011-12-01

Using a technological system proposed by the authors, a combined process is developed for formation of stratified-gradient surface layers and multicomponent coatings. It is implemented under the conditions of a combined serial-parallel operation of a hot-cathode gas plasma generator and a duomagnetron with two targets and two electric-arc evaporators. The extended functional potential is ensured by using advanced multi-element and multi-phase cathode targets made of borides, carbides, silicides, and sulfides of metals produced by the SHS-process followed by their immediate compaction. The variations in composition, structure, and physicomechanical properties in the cross-section of the stratified-gradient surface layers and coating is provided by a predetermined alternating replacement of the sputtered cathode targets of the plasma sources, the plasma flow intensity ratios, and variation in the particle energy incident on the substrate, which is determined by the accelerating voltage on the substrate.

Layer-by-Layer Proteomic Analysis of Mytilus galloprovincialis Shell

PubMed Central

Wang, Xin-xing; Bao, Lin-fei; Fan, Mei-hua; Li, Xiao-min; Wu, Chang-wen; Xia, Shu-wei

2015-01-01

Bivalve shell is a biomineralized tissue with various layers/microstructures and excellent mechanical properties. Shell matrix proteins (SMPs) pervade and envelop the mineral crystals and play essential roles in biomineralization. Despite that Mytilus is an economically important bivalve, only few proteomic studies have been performed for the shell, and current knowledge of the SMP set responsible for different shell layers of Mytilus remains largely patchy. In this study, we observed that Mytilus galloprovincialis shell contained three layers, including nacre, fibrous prism, and myostracum that is involved in shell-muscle attachment. A parallel proteomic analysis was performed for these three layers. By combining LC-MS/MS analysis with Mytilus EST database interrogations, a whole set of 113 proteins was identified, and the distribution of these proteins in different shell layers followed a mosaic pattern. For each layer, about a half of identified proteins are unique and the others are shared by two or all of three layers. This is the first description of the protein set exclusive to nacre, myostracum, and fibrous prism in Mytilus shell. Moreover, most of identified proteins in the present study are novel SMPs, which greatly extended biomineralization-related protein data of Mytilus. These results are useful, on one hand, for understanding the roles of SMPs in the deposition of different shell layers. On the other hand, the identified protein set of myostracum provides candidates for further exploring the mechanism of adductor muscle-shell attachment. PMID:26218932

Scaling of Electron Heating During Magnetic Reconnection

NASA Astrophysics Data System (ADS)

Ohia, O.; Le, A.; Daughton, W. S.; Egedal, J.

2016-12-01

While magnetic reconnection plays a major role in accelerating and heating magnetospheric plasma, it remains poorly understood how the level of particle energization depends on the plasma conditions. Meanwhile, a recent survey of THEMIS magnetopause reconnection observations [Phan et al. GRL 2013] and a numerical study [Shay et al. PoP 2014] found empirically that the electron heating scales with the square of the upstream Alfven speed. Equivalently for weak guide fields, the fractional electron temperature increase is inversely proportional to the upstream electron beta (ratio of electron to magnetic pressure). We present models for symmetric reconnection with moderate [Ohia et al., GRL 2015] or zero guide field that predict the electron bulk heating. In the models, adiabatically trapped electrons gain energy from parallel electric fields in the inflowing region. For purely anti-parallel reconnection, meandering electrons receive additional energy from the reconnection electric field. The predicted scalings are in quantitative agreement with fluid and kinetic simulations, as well as spacecraft observations. Using kinetic simulations, we extend this work to explore how the layer dynamics and electron bulk heating vary as functions of the magnetic shear and plasma and magnetic pressure asymmetry across the reconnection layer. These results are pertinent to recent Magnetospheric Multiscale (MMS) Mission measurements of electron dynamics during dayside magnetopause reconnection.

Direct numerical simulation of instabilities in parallel flow with spherical roughness elements

NASA Technical Reports Server (NTRS)

Deanna, R. G.

1992-01-01

Results from a direct numerical simulation of laminar flow over a flat surface with spherical roughness elements using a spectral-element method are given. The numerical simulation approximates roughness as a cellular pattern of identical spheres protruding from a smooth wall. Periodic boundary conditions on the domain's horizontal faces simulate an infinite array of roughness elements extending in the streamwise and spanwise directions, which implies the parallel-flow assumption, and results in a closed domain. A body force, designed to yield the horizontal Blasius velocity in the absence of roughness, sustains the flow. Instabilities above a critical Reynolds number reveal negligible oscillations in the recirculation regions behind each sphere and in the free stream, high-amplitude oscillations in the layer directly above the spheres, and a mean profile with an inflection point near the sphere's crest. The inflection point yields an unstable layer above the roughness (where U''(y) is less than 0) and a stable region within the roughness (where U''(y) is greater than 0). Evidently, the instability begins when the low-momentum or wake region behind an element, being the region most affected by disturbances (purely numerical in this case), goes unstable and moves. In compressible flow with periodic boundaries, this motion sends disturbances to all regions of the domain. In the unstable layer just above the inflection point, the disturbances grow while being carried downstream with a propagation speed equal to the local mean velocity; they do not grow amid the low energy region near the roughness patch. The most amplified disturbance eventually arrives at the next roughness element downstream, perturbing its wake and inducing a global response at a frequency governed by the streamwise spacing between spheres and the mean velocity of the most amplified layer.

Parallel simulation of tsunami inundation on a large-scale supercomputer

NASA Astrophysics Data System (ADS)

Oishi, Y.; Imamura, F.; Sugawara, D.

2013-12-01

An accurate prediction of tsunami inundation is important for disaster mitigation purposes. One approach is to approximate the tsunami wave source through an instant inversion analysis using real-time observation data (e.g., Tsushima et al., 2009) and then use the resulting wave source data in an instant tsunami inundation simulation. However, a bottleneck of this approach is the large computational cost of the non-linear inundation simulation and the computational power of recent massively parallel supercomputers is helpful to enable faster than real-time execution of a tsunami inundation simulation. Parallel computers have become approximately 1000 times faster in 10 years (www.top500.org), and so it is expected that very fast parallel computers will be more and more prevalent in the near future. Therefore, it is important to investigate how to efficiently conduct a tsunami simulation on parallel computers. In this study, we are targeting very fast tsunami inundation simulations on the K computer, currently the fastest Japanese supercomputer, which has a theoretical peak performance of 11.2 PFLOPS. One computing node of the K computer consists of 1 CPU with 8 cores that share memory, and the nodes are connected through a high-performance torus-mesh network. The K computer is designed for distributed-memory parallel computation, so we have developed a parallel tsunami model. Our model is based on TUNAMI-N2 model of Tohoku University, which is based on a leap-frog finite difference method. A grid nesting scheme is employed to apply high-resolution grids only at the coastal regions. To balance the computation load of each CPU in the parallelization, CPUs are first allocated to each nested layer in proportion to the number of grid points of the nested layer. Using CPUs allocated to each layer, 1-D domain decomposition is performed on each layer. In the parallel computation, three types of communication are necessary: (1) communication to adjacent neighbours for the finite difference calculation, (2) communication between adjacent layers for the calculations to connect each layer, and (3) global communication to obtain the time step which satisfies the CFL condition in the whole domain. A preliminary test on the K computer showed the parallel efficiency on 1024 cores was 57% relative to 64 cores. We estimate that the parallel efficiency will be considerably improved by applying a 2-D domain decomposition instead of the present 1-D domain decomposition in future work. The present parallel tsunami model was applied to the 2011 Great Tohoku tsunami. The coarsest resolution layer covers a 758 km × 1155 km region with a 405 m grid spacing. A nesting of five layers was used with the resolution ratio of 1/3 between nested layers. The finest resolution region has 5 m resolution and covers most of the coastal region of Sendai city. To complete 2 hours of simulation time, the serial (non-parallel) computation took approximately 4 days on a workstation. To complete the same simulation on 1024 cores of the K computer, it took 45 minutes which is more than two times faster than real-time. This presentation discusses the updated parallel computational performance and the efficient use of the K computer when considering the characteristics of the tsunami inundation simulation model in relation to the characteristics and capabilities of the K computer.

PIXIE3D: A Parallel, Implicit, eXtended MHD 3D Code

NASA Astrophysics Data System (ADS)

Chacon, Luis

2006-10-01

We report on the development of PIXIE3D, a 3D parallel, fully implicit Newton-Krylov extended MHD code in general curvilinear geometry. PIXIE3D employs a second-order, finite-volume-based spatial discretization that satisfies remarkable properties such as being conservative, solenoidal in the magnetic field to machine precision, non-dissipative, and linearly and nonlinearly stable in the absence of physical dissipation. PIXIE3D employs fully-implicit Newton-Krylov methods for the time advance. Currently, second-order implicit schemes such as Crank-Nicolson and BDF2 (2^nd order backward differentiation formula) are available. PIXIE3D is fully parallel (employs PETSc for parallelism), and exhibits excellent parallel scalability. A parallel, scalable, MG preconditioning strategy, based on physics-based preconditioning ideas, has been developed for resistive MHD, and is currently being extended to Hall MHD. In this poster, we will report on progress in the algorithmic formulation for extended MHD, as well as the the serial and parallel performance of PIXIE3D in a variety of problems and geometries. L. Chac'on, Comput. Phys. Comm., 163 (3), 143-171 (2004) L. Chac'on et al., J. Comput. Phys. 178 (1), 15- 36 (2002); J. Comput. Phys., 188 (2), 573-592 (2003) L. Chac'on, 32nd EPS Conf. Plasma Physics, Tarragona, Spain, 2005 L. Chac'on et al., 33rd EPS Conf. Plasma Physics, Rome, Italy, 2006

The Neuronal Organization of a Unique Cerebellar Specialization: The Valvula Cerebelli of a Mormyrid Fish

PubMed Central

Shi, Zhigang; Zhang, Yueping; Meek, Johannes; Qiao, Jiantian; Han, Victor Z.

2018-01-01

The distal valvula cerebelli is the most prominent part of the mormyrid cerebellum. It is organized in ridges of ganglionic and molecular layers, oriented perpendicular to the granular layer. We have combined intracellular recording and labelling techniques to reveal the cellular morphology of the valvula ridges in slice preparations. We have also locally ejected tracer in slices and in intact animals to examine its input fibers. The palisade dendrites and fine axon arbors of Purkinje cells are oriented in the horizontal plane of the ridge. The dendrites of basal efferent cells and large central cells are confined to the molecular layer, but are not planer. Basal efferent cell axons are thick, and join the basal bundle leaving the cerebellum. Large central cell axons are also thick, and traverse long distances in the transverse plane, with local collaterals in the ganglionic layer. Vertical cells and small central cells also have thick axons with local collaterals. The dendrites of Golgi cells are confined to the molecular layer, but their axon arbors are either confined to the granular layer or proliferate in both the granular and ganglionic layers. Dendrites of deep stellate cells are distributed in the molecular layer, with fine axon arbors in the ganglionic layer. Granule cell axons enter the molecular layer as parallel fibers without bifurcating. Climbing fibers run in the horizontal plane and terminate exclusively in the ganglionic layer. Our results confirm and extend previous studies and suggest a new concept of the circuitry of the mormyrid valvula cerebelli. PMID:18537139

Corrosion Prediction with Parallel Finite Element Modeling for Coupled Hygro-Chemo Transport into Concrete under Chloride-Rich Environment

PubMed Central

Na, Okpin; Cai, Xiao-Chuan; Xi, Yunping

2017-01-01

The prediction of the chloride-induced corrosion is very important because of the durable life of concrete structure. To simulate more realistic durability performance of concrete structures, complex scientific methods and more accurate material models are needed. In order to predict the robust results of corrosion initiation time and to describe the thin layer from concrete surface to reinforcement, a large number of fine meshes are also used. The purpose of this study is to suggest more realistic physical model regarding coupled hygro-chemo transport and to implement the model with parallel finite element algorithm. Furthermore, microclimate model with environmental humidity and seasonal temperature is adopted. As a result, the prediction model of chloride diffusion under unsaturated condition was developed with parallel algorithms and was applied to the existing bridge to validate the model with multi-boundary condition. As the number of processors increased, the computational time decreased until the number of processors became optimized. Then, the computational time increased because the communication time between the processors increased. The framework of present model can be extended to simulate the multi-species de-icing salts ingress into non-saturated concrete structures in future work. PMID:28772714

Magnetic spectral signatures in the Earth's magnetosheath and plasma depletion layer

NASA Technical Reports Server (NTRS)

Anderson, Brian J.; Fuselier, Stephen A.; Gary, S. Peter; Denton, Richard E.

1994-01-01

Correlations between plasma properties and magnetic fluctuations in the sub-solar magnetosheath downstream of a quasi-perpendicular shock have been found and indicate that mirror and ion cyclotronlike fluctuations correlate with the magnetosheath proper and plasma depletion layer, respectively (Anderson and Fueselier, 1993). We explore the entire range of magnetic spectral signatures observed from the Active Magnetospheric Particle Tracer Explorers/Charge Composition Explorer (AMPTE/CCE)spacecraft in the magnetosheath downstream of a quasi-perpendicular shock. The magnetic spectral signatures typically progress from predominantly compressional fluctuations,delta B(sub parallel)/delta B perpendicular to approximately 3, with F/F (sub p) less than 0.2 (F and F (sub p) are the wave frequency and proton gyrofrequency, respectively) to predominantly transverse fluctuations, delta B(sub parallel)/delta B perpendicular to approximately 0.3, extending up to F(sub p). The compressional fluctuations are characterized by anticorrelation between the field magnitude and electron density, n(sub e), and by a small compressibility, C(sub e) identically equal to (delta n(sub e)/n(sub e)) (exp 2) (B/delta B(sub parallel)) (exp 2) approximately 0.13, indicative of mirror waves. The spectral characteristics of the transverse fluctuations are in agreement with predictions of linear Vlasov theory for the H(+) and He(2+) cyclotron modes. The power spectra and local plasma parameters are found to vary in concert: mirror waves occur for beta(s ub parallel p) (beta (sub parallel p) identically = 2 mu(sub zero) n(sub p) kT (sub parallel p) / B(exp 2) approximately = 2, A(sub p) indentically = T(sub perpendicular to p)/T(sub parallel p) - 1 approximately = 0.4, whereas cyclotron waves occur for beta (sub parallel p) approximately = 0.2 and A(sub p) approximately = 2. The transition from mirror to cyclotron modes is predicted by linear theory. The spectral characteristics overlap for intermediate plasma parameters. The plasma observations are described by A(sub p) = 0.85 beta(sub parallel P) (exp - 0.48) with a log regression coefficient of -0.74. This inverse A(sub p) - beta(sub parallel p) correlation corresponds closely to the isocontours of maximum ion anisotropy instability growth, gamma (sub m)/omega(sub p) = 0.01, for the mirror and cyclotron modes. The agreement of observed properties and predictions of local theory suggests that the spectral signatures reflect the local plasma environment and that the anisotropy instabilities regulate A(sub p). We suggest that the spectral characteristics may provide a useful basis for ordering observations in the magnetosheath and that the A(sub p) - beta(sub parallel p) inverse correlation may be used as a beta-dependent upper limit on the proton anisotropy to represent kinetic effects.

Roughness-induced generation of crossflow vortices in three-dimensional boundary layers

NASA Technical Reports Server (NTRS)

Choudhari, Meelan

1993-01-01

The receptivity theory of Goldstein and Ruban is extended within the nonasymptotic (quasi-parallel) framework of Zavol'skii et al to predict the roughness-induced generation of stationary and nonstationary instability waves in three-dimensional, incompressible boundary layers. The influence of acoustic-wave orientation, as well as that of different types of roughness geometries, including isolated roughness elements, periodic arrays, and two-dimensional lattices of compact roughness shapes, as well as random, but spatially homogeneous roughness distributions, is examined. The parametric study for the Falkner-Skan-Cooke family of boundary layers supports our earlier conjecture that the initial amplitudes of roughness-induced stationary vortices are likely to be significantly larger than the amplitudes of similarly induced nonstationary vortices in the presence of acoustic disturbances in the free stream. Maximum unsteady receptivity occurs when the acoustic velocity fluctuation is aligned with the wavenumber vector of the unsteady vortex mode. On the other hand, roughness arrays that are oriented somewhere close to the group velocity direction are likely to produce higher instability amplitudes. Limitations of the nonasymptotic theory are discussed, and future work is suggested.

Extending Automatic Parallelization to Optimize High-Level Abstractions for Multicore

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

Liao, C; Quinlan, D J; Willcock, J J

2008-12-12

Automatic introduction of OpenMP for sequential applications has attracted significant attention recently because of the proliferation of multicore processors and the simplicity of using OpenMP to express parallelism for shared-memory systems. However, most previous research has only focused on C and Fortran applications operating on primitive data types. C++ applications using high-level abstractions, such as STL containers and complex user-defined types, are largely ignored due to the lack of research compilers that are readily able to recognize high-level object-oriented abstractions and leverage their associated semantics. In this paper, we automatically parallelize C++ applications using ROSE, a multiple-language source-to-source compiler infrastructuremore » which preserves the high-level abstractions and gives us access to their semantics. Several representative parallelization candidate kernels are used to explore semantic-aware parallelization strategies for high-level abstractions, combined with extended compiler analyses. Those kernels include an array-base computation loop, a loop with task-level parallelism, and a domain-specific tree traversal. Our work extends the applicability of automatic parallelization to modern applications using high-level abstractions and exposes more opportunities to take advantage of multicore processors.« less

Megavolt parallel potentials arising from double-layer streams in the Earth's outer radiation belt.

PubMed

Mozer, F S; Bale, S D; Bonnell, J W; Chaston, C C; Roth, I; Wygant, J

2013-12-06

Huge numbers of double layers carrying electric fields parallel to the local magnetic field line have been observed on the Van Allen probes in connection with in situ relativistic electron acceleration in the Earth's outer radiation belt. For one case with adequate high time resolution data, 7000 double layers were observed in an interval of 1 min to produce a 230,000 V net parallel potential drop crossing the spacecraft. Lower resolution data show that this event lasted for 6 min and that more than 1,000,000 volts of net parallel potential crossed the spacecraft during this time. A double layer traverses the length of a magnetic field line in about 15 s and the orbital motion of the spacecraft perpendicular to the magnetic field was about 700 km during this 6 min interval. Thus, the instantaneous parallel potential along a single magnetic field line was the order of tens of kilovolts. Electrons on the field line might experience many such potential steps in their lifetimes to accelerate them to energies where they serve as the seed population for relativistic acceleration by coherent, large amplitude whistler mode waves. Because the double-layer speed of 3100  km/s is the order of the electron acoustic speed (and not the ion acoustic speed) of a 25 eV plasma, the double layers may result from a new electron acoustic mode. Acceleration mechanisms involving double layers may also be important in planetary radiation belts such as Jupiter, Saturn, Uranus, and Neptune, in the solar corona during flares, and in astrophysical objects.

Parallelization of the Flow Field Dependent Variation Scheme for Solving the Triple Shock/Boundary Layer Interaction Problem

NASA Technical Reports Server (NTRS)

Schunk, Richard Gregory; Chung, T. J.

2001-01-01

A parallelized version of the Flowfield Dependent Variation (FDV) Method is developed to analyze a problem of current research interest, the flowfield resulting from a triple shock/boundary layer interaction. Such flowfields are often encountered in the inlets of high speed air-breathing vehicles including the NASA Hyper-X research vehicle. In order to resolve the complex shock structure and to provide adequate resolution for boundary layer computations of the convective heat transfer from surfaces inside the inlet, models containing over 500,000 nodes are needed. Efficient parallelization of the computation is essential to achieving results in a timely manner. Results from a parallelization scheme, based upon multi-threading, as implemented on multiple processor supercomputers and workstations is presented.

Trauma and daimonic reality in Ferenczi's later work.

PubMed

Kalsched, Donald

2003-09-01

Jung and Ferenczi made independent discoveries of an 'archaic' (Jung) or 'primordial' (Ferenczi) layer of the psyche that shone through the 'basic fault' in the psyche opened by childhood trauma. This paper explores those parallels through an extended vignette of Ferenczi's work with Elizabeth Severn, known as 'R. N.' in the Clinical Diary. A remarkable inner object known as 'Orpha' appeared in the patient's trauma experience and saved a seed of personality from total annihilation. Ferenczi's speculation about this 'daimonic' object is cited along with his discussion of a transpersonal immaterial reality that Orpha makes visible, and that links the patient's ego-experience with a spiritual/material unity not ordinarily available to consciousness.

Fast parallel algorithm for slicing STL based on pipeline

NASA Astrophysics Data System (ADS)

Ma, Xulong; Lin, Feng; Yao, Bo

2016-05-01

In Additive Manufacturing field, the current researches of data processing mainly focus on a slicing process of large STL files or complicated CAD models. To improve the efficiency and reduce the slicing time, a parallel algorithm has great advantages. However, traditional algorithms can't make full use of multi-core CPU hardware resources. In the paper, a fast parallel algorithm is presented to speed up data processing. A pipeline mode is adopted to design the parallel algorithm. And the complexity of the pipeline algorithm is analyzed theoretically. To evaluate the performance of the new algorithm, effects of threads number and layers number are investigated by a serial of experiments. The experimental results show that the threads number and layers number are two remarkable factors to the speedup ratio. The tendency of speedup versus threads number reveals a positive relationship which greatly agrees with the Amdahl's law, and the tendency of speedup versus layers number also keeps a positive relationship agreeing with Gustafson's law. The new algorithm uses topological information to compute contours with a parallel method of speedup. Another parallel algorithm based on data parallel is used in experiments to show that pipeline parallel mode is more efficient. A case study at last shows a suspending performance of the new parallel algorithm. Compared with the serial slicing algorithm, the new pipeline parallel algorithm can make full use of the multi-core CPU hardware, accelerate the slicing process, and compared with the data parallel slicing algorithm, the new slicing algorithm in this paper adopts a pipeline parallel model, and a much higher speedup ratio and efficiency is achieved.

Magnetic behaviour of multisegmented FeCoCu/Cu electrodeposited nanowires

NASA Astrophysics Data System (ADS)

Núñez, A.; Pérez, L.; Abuín, M.; Araujo, J. P.; Proenca, M. P.

2017-04-01

Understanding the magnetic behaviour of multisegmented nanowires (NWs) is a major key for the application of such structures in future devices. In this work, magnetic/non-magnetic arrays of FeCoCu/Cu multilayered NWs electrodeposited in nanoporous alumina templates are studied. Contrarily to most reports on multilayered NWs, the magnetic layer thickness was kept constant (30 nm) and only the non-magnetic layer thickness was changed (0 to 80 nm). This allowed us to tune the interwire and intrawire interactions between the magnetic layers in the NW array creating a three-dimensional (3D) magnetic system without the need to change the template characteristics. Magnetic hysteresis loops, measured with the applied field parallel and perpendicular to the NWs’ long axis, showed the effect of the non-magnetic Cu layer on the overall magnetic properties of the NW arrays. In particular, introducing Cu layers along the magnetic NW axis creates domain wall nucleation sites that facilitate the magnetization reversal of the wires, as seen by the decrease in the parallel coercivity and the reduction of the perpendicular saturation field. By further increasing the Cu layer thickness, the interactions between the magnetic segments, both along the NW axis and of neighbouring NWs, decrease, thus rising again the parallel coercivity and the perpendicular saturation field. This work shows how one can easily tune the parallel and perpendicular magnetic properties of a 3D magnetic layer system by adjusting the non-magnetic layer thickness.

A Theoretical Study of Cold Air Damming.

NASA Astrophysics Data System (ADS)

Xu, Qin

1990-12-01

The dynamics of cold air damming are examined analytically with a two-layer steady state model. The upper layer is a warm and saturated cross-mountain (easterly or southeasterly onshore) flow. The lower layer is a cold mountain-parallel (northerly) jet trapped on the windward (eastern) side of the mountain. The interface between the two layers represents a coastal front-a sloping inversion layer coupling the trapped cold dome with the warm onshore flow above through pressure continuity.An analytical expression is obtained for the inviscid upper-layer flow with hydrostatic and moist adiabatic approximations. Blackadar's PBL parameterization of eddy viscosity is used in the lower-layer equations. Solutions for the mountain-parallel jet and its associated secondary transverse circulation are obtained by expanding asymptotically upon a small parameter proportional to the square root of the inertial aspect ratio-the ratio between the mountain height and the radius of inertial oscillation. The geometric shape of the sloping interface is solved numerically from a differential-integral equation derived from the pressure continuity condition imposed at the interface.The observed flow structures and force balances of cold air damming events are produced qualitatively by the model. In the cold dome the mountain-parallel jet is controlled by the competition between the mountain-parallel pressure gradient and friction: the jet is stronger with smoother surfaces, higher mountains, and faster mountain-normal geostrophic winds. In the mountain-normal direction the vertically averaged force balance in the cold dome is nearly geostrophic and controls the geometric shape of the cold dome. The basic mountain-normal pressure gradient generated in the cold dome by the negative buoyancy distribution tends to flatten the sloping interface and expand the cold dome upstream against the mountain-normal pressure gradient (produced by the upper-layer onshore wind) and Coriolis force (induced by the lower-layer mountain-parallel jet). It is found that the interface slope increases and the cold dome shrinks as the Froude number and/or upstream mountain-parallel geostrophic wind increase, or as the Rossby number, upper-layer depth, and/or surface roughness length decrease, and vice versa. The cold dome will either vanish or not be in a steady state if the Froude number is large enough or the roughness length gets too small. The theoretical findings are explained physically based on detailed analyses of the force balance along the inversion interface.

Kinematic analysis of melange fabrics: Examples and applications from the McHugh Complex, Kenai Peninsula, Alaska

USGS Publications Warehouse

Kusky, T.M.; Bradley, D.C.

1999-01-01

Permian to Cretaceous melange of the McHugh Complex on the Kenai Peninsula, south-central Alaska includes blocks and belts of graywacke, argillite, limestone, chert, basalt, gabbro, and ultramafic rocks, intruded by a variety of igneous rocks. An oceanic plate stratigraphy is repeated hundreds of times across the map area, but most structures at the outcrop scale extend lithological layering. Strong rheological units occur as blocks within a matrix that flowed around the competent blocks during deformation, forming broken formation and melange. Deformation was noncoaxial, and disruption of primary layering was a consequence of general strain driven by plate convergence in a relatively narrow zone between the overriding accretionary wedge and the downgoing, generally thinly sedimented oceanic plate. Soft-sediment deformation processes do not appear to have played a major role in the formation of the melange. A model for deformation at the toe of the wedge is proposed in which layers oriented at low angles to ??1 are contracted in both the brittle and ductile regimes, layers at 30-45??to ??1 are extended in the brittle regime and contracted in the ductile regime, and layers at angles greater than 45??to ??1 are extended in both the brittle and ductile regimes. Imbrication in thrust duplexes occurs at deeper levels within the wedge. Many structures within melange of the McHugh Complex are asymmetric and record kinematic information consistent with the inferred structural setting in an accretionary wedge. A displacement field for the McHugh Complex on the lower Kenai Peninsula includes three belts: an inboard belt of Late Triassic rocks records west-to-east-directed slip of hanging walls, a central belt of predominantly Early Jurassic rocks records north-south directed displacements, and Early Cretaceous rocks in an outboard belt preserve southwest-northeast directed slip vectors. Although precise ages of accretion are unknown, slip directions are compatible with inferred plate motions during the general time frame of accretion of the McHugh Complex. The slip vectors are interpreted to preserve the convergence directions between the overriding and underriding plates, which became more oblique with time. They are not considered indicative of strain partitioning into belts of orogen-parallel and orogen-perpendicular displacements, because the kinematic data are derived from the earliest preserved structures, whereas fabrics related to strain partitioning would be expected to be superimposed on earlier accretion-related fabrics.Permian to Cretaceous melange of the McHugh Complex on the Kenai Peninsula, south-central Alaska includes blocks and belts of graywacke, argillite, limestone, chert, basalt, gabbro, and ultramafic rocks, intruded by a variety of igneous rocks. An oceanic plate stratigraphy is repeated hundreds of times across the map area, but most structures at the outcrop scale extend lithological layering. Strong rheological units occur as blocks within a matrix that flowed around the competent blocks during deformation, forming broken formation and melange. Deformation was noncoaxial, and disruption of primary layering was a consequence of general strain driven by plate convergence in a relatively narrow zone between the overriding accretionary wedge and the downgoing, generally thinly sedimented oceanic plate. Soft-sediment deformation processes do not appear to have played a major role in the formation of the melange. A model for deformation at the toe of the wedge is proposed in which layers oriented at low angles to ??1 are contracted in both the brittle and ductile regimes, layers at 30-45?? to ??1 are extended in the brittle regime and contracted in the ductile regime, and layers at angles greater than 45?? to ??1 are extended in both the brittle and ductile regimes. Imbrication in thrust duplexes occurs at deeper levels within the wedge. Many structures within melange of the McHugh Complex are asymmetric and record

HPC in Basin Modeling: Simulating Mechanical Compaction through Vertical Effective Stress using Level Sets

NASA Astrophysics Data System (ADS)

McGovern, S.; Kollet, S. J.; Buerger, C. M.; Schwede, R. L.; Podlaha, O. G.

2017-12-01

In the context of sedimentary basins, we present a model for the simulation of the movement of ageological formation (layers) during the evolution of the basin through sedimentation and compactionprocesses. Assuming a single phase saturated porous medium for the sedimentary layers, the modelfocuses on the tracking of the layer interfaces, through the use of the level set method, as sedimentationdrives fluid-flow and reduction of pore space by compaction. On the assumption of Terzaghi's effectivestress concept, the coupling of the pore fluid pressure to the motion of interfaces in 1-D is presented inMcGovern, et.al (2017) [1] .The current work extends the spatial domain to 3-D, though we maintain the assumption ofvertical effective stress to drive the compaction. The idealized geological evolution is conceptualized asthe motion of interfaces between rock layers, whose paths are determined by the magnitude of a speedfunction in the direction normal to the evolving layer interface. The speeds normal to the interface aredependent on the change in porosity, determined through an effective stress-based compaction law,such as the exponential Athy's law. Provided with the speeds normal to the interface, the level setmethod uses an advection equation to evolve a potential function, whose zero level set defines theinterface. Thus, the moving layer geometry influences the pore pressure distribution which couplesback to the interface speeds. The flexible construction of the speed function allows extension, in thefuture, to other terms to represent different physical processes, analogous to how the compaction rulerepresents material deformation.The 3-D model is implemented using the generic finite element method framework Deal II,which provides tools, building on p4est and interfacing to PETSc, for the massively parallel distributedsolution to the model equations [2]. Experiments are being run on the Juelich Supercomputing Center'sJureca cluster. [1] McGovern, et.al. (2017). Novel basin modelling concept for simulating deformation from mechanical compaction using level sets. Computational Geosciences, SI:ECMOR XV, 1-14.[2] Bangerth, et. al. (2011). Algorithms and data structures for massively parallel generic adaptive finite element codes. ACM Transactions on Mathematical Software (TOMS), 38(2):14.

The Extended Parallel Process Model: Illuminating the Gaps in Research

ERIC Educational Resources Information Center

Popova, Lucy

2012-01-01

This article examines constructs, propositions, and assumptions of the extended parallel process model (EPPM). Review of the EPPM literature reveals that its theoretical concepts are thoroughly developed, but the theory lacks consistency in operational definitions of some of its constructs. Out of the 12 propositions of the EPPM, a few have not…

Fear Control an Danger Control: A Test of the Extended Parallel Process Model (EPPM).

ERIC Educational Resources Information Center

Witte, Kim

1994-01-01

Explores cognitive and emotional mechanisms underlying success and failure of fear appeals in context of AIDS prevention. Offers general support for Extended Parallel Process Model. Suggests that cognitions lead to fear appeal success (attitude, intention, or behavior changes) via danger control processes, whereas the emotion fear leads to fear…

Cooled particle accelerator target

DOEpatents

Degtiarenko, Pavel V.

2005-06-14

A novel particle beam target comprising: a rotating target disc mounted on a retainer and thermally coupled to a first array of spaced-apart parallel plate fins that extend radially inwardly from the retainer and mesh without physical contact with a second array of spaced-apart parallel plate fins that extend radially outwardly from and are thermally coupled to a cooling mechanism capable of removing heat from said second array of spaced-apart fins and located within the first array of spaced-apart parallel fins. Radiant thermal exchange between the two arrays of parallel plate fins provides removal of heat from the rotating disc. A method of cooling the rotating target is also described.

Light trapping architecture for photovoltaic and photodector applications

DOEpatents

Forrest, Stephen R.; Lunt, Richard R.; Slootsky, Michael

2016-08-09

There is disclosed photovoltaic device structures which trap admitted light and recycle it through the contained photosensitive materials to maximize photoabsorption. For example, there is disclosed a photosensitive optoelectronic device comprising: a first reflective layer comprising a thermoplastic resin; a second reflective layer substantially parallel to the first reflective layer; a first transparent electrode layer on at least one of the first and second reflective layer; and a photosensitive region adjacent to the first electrode, wherein the first transparent electrode layer is substantially parallel to the first reflective layer and adjacent to the photosensitive region, and wherein the device has an exterior face transverse to the planes of the reflective layers where the exterior face has an aperture for admission of incident radiation to the interior of the device.

Bioconvection in spatially extended domains

NASA Astrophysics Data System (ADS)

Karimi, A.; Paul, M. R.

2013-05-01

We numerically explore gyrotactic bioconvection in large spatially extended domains of finite depth using parameter values from available experiments with the unicellular alga Chlamydomonas nivalis. We numerically integrate the three-dimensional, time-dependent continuum model of Pedley [J. Fluid Mech.10.1017/S0022112088002393 195, 223 (1988)] using a high-order, parallel, spectral-element approach. We explore the long-time nonlinear patterns and dynamics found for layers with an aspect ratio of 10 over a range of Rayleigh numbers. Our results yield the pattern wavelength and pattern dynamics which we compare with available theory and experimental measurement. There is good agreement for the pattern wavelength at short times between numerics, experiment, and a linear stability analysis. At long times we find that the general sequence of patterns given by the nonlinear evolution of the governing equations correspond qualitatively to what has been described experimentally. However, at long times the patterns in numerics grow to larger wavelengths, in contrast to what is observed in experiment where the wavelength is found to decrease with time.

Unsteady boundary-layer injection

NASA Technical Reports Server (NTRS)

Telionis, D. P.; Jones, G. S.

1981-01-01

The boundary-layer equations for two-dimensional incompressible flow are integrated numerically for the flow over a flat plate and a Howarth body. Injection is introduced either impulsively or periodically along a narrow strip. Results indicate that injection perpendicular to the wall is transmitted instantly across the boundary layer and has little effect on the velocity profile parallel to the wall. The effect is a little more noticeable for flows with adverse pressure gradients. Injection parallel to the wall results in fuller velocity profiles. Parallel and oscillatory injection appears to influence the mean. The amplitude of oscillation decreases with distance from the injection strip but further downstream it increases again in a manner reminiscent of an unstable process.

13-fold resolution gain through turbid layer via translated unknown speckle illumination

PubMed Central

Guo, Kaikai; Zhang, Zibang; Jiang, Shaowei; Liao, Jun; Zhong, Jingang; Eldar, Yonina C.; Zheng, Guoan

2017-01-01

Fluorescence imaging through a turbid layer holds great promise for various biophotonics applications. Conventional wavefront shaping techniques aim to create and scan a focus spot through the turbid layer. Finding the correct input wavefront without direct access to the target plane remains a critical challenge. In this paper, we explore a new strategy for imaging through turbid layer with a large field of view. In our setup, a fluorescence sample is sandwiched between two turbid layers. Instead of generating one focus spot via wavefront shaping, we use an unshaped beam to illuminate the turbid layer and generate an unknown speckle pattern at the target plane over a wide field of view. By tilting the input wavefront, we raster scan the unknown speckle pattern via the memory effect and capture the corresponding low-resolution fluorescence images through the turbid layer. Different from the wavefront-shaping-based single-spot scanning, the proposed approach employs many spots (i.e., speckles) in parallel for extending the field of view. Based on all captured images, we jointly recover the fluorescence object, the unknown optical transfer function of the turbid layer, the translated step size, and the unknown speckle pattern. Without direct access to the object plane or knowledge of the turbid layer, we demonstrate a 13-fold resolution gain through the turbid layer using the reported strategy. We also demonstrate the use of this technique to improve the resolution of a low numerical aperture objective lens allowing to obtain both large field of view and high resolution at the same time. The reported method provides insight for developing new fluorescence imaging platforms and may find applications in deep-tissue imaging. PMID:29359102

Block Copolymer-Templated Approach to Nanopatterned Metal-Organic Framework Films.

PubMed

Zhou, Meimei; Wu, Yi-Nan; Wu, Baozhen; Yin, Xianpeng; Gao, Ning; Li, Fengting; Li, Guangtao

2017-08-17

The fabrication of patterned metal-organic framework (MOF) films with precisely controlled nanoscale resolution has been a fundamental challenge in nanoscience and nanotechnology. In this study, nanopatterned MOF films were fabricated using a layer-by-layer (LBL) growth method on functional templates (such as a bicontinuous nanoporous membrane or a structure with highly long-range-ordered nanoscopic channels parallel to the underlying substrate) generated by the microphase separation of polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) block copolymers. HKUST-1 can be directly deposited on the templates without any chemical modification because the pyridine groups in P2VP interact with metal ions via metal-BCP complexes. As a result, nanopatterned HKUST-1 films with feature sizes below 50 nm and controllable thicknesses can be fabricated by controlling the number of LBL growth cycles. The proposed fabrication method further extends the applications of MOFs in various fields. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crystal structure of bis[bis(4-azaniumylphenyl) sulfone] tetranitrate monohydrate

PubMed Central

Benahsene, Amani Hind; Bendjeddou, Lamia; Merazig, Hocine

2017-01-01

In the title compound, the hydrated tetra­(nitrate) salt of dapsone (4,4′-di­amino­diphenyl­sulfone), 2C12H14N2O2S2+·4NO3 −·H2O {alternative name: bis[bis­(4,4′-di­aza­niumylphen­yl) sulfone] tetra­nitrate monohydrate}, the cations are conformationally similar, with comparable dihedral angles between the two benzene rings in each of 70.03 (18) and 69.69 (19)°. In the crystal, mixed cation–anion–water mol­ecule layers lying parallel to the (001) plane are formed through N—H⋯O, O—H⋯O and C—H⋯O hydrogen-bonding inter­actions and these layers are further extended into an overall three-dimensional supra­molecular network structure. Inter-ring π–π inter­actions are also present [minimum ring centroid separation = 3.693 (3) Å]. PMID:29152359

Analysis of the electromagnetic scattering from an inlet geometry with lossy walls

NASA Technical Reports Server (NTRS)

Myung, N. H.; Pathak, P. H.; Chunang, C. D.

1985-01-01

One of the primary goals is to develop an approximate but sufficiently accurate analysis for the problem of electromagnetic (EM) plane wave scattering by an open ended, perfectly-conducting, semi-infinite hollow circular waveguide (or duct) with a thin, uniform layer of lossy or absorbing material on its inner wall, and with a simple termination inside. The less difficult but useful problem of the EM scattering by a two-dimensional (2-D), semi-infinite parallel plate waveguide with an impedance boundary condition on the inner walls was chosen initially for analysis. The impedance boundary condition in this problem serves to model a thin layer of lossy dielectric/ferrite coating on the otherwise perfectly-conducting interior waveguide walls. An approximate but efficient and accurate ray solution was obtained recently. That solution is presently being extended to the case of a moderately thick dielectric/ferrite coating on the walls so as to be valid for situations where the impedance boundary condition may not remain sufficiently accurate.

On the stability of a time dependent boundary layer

NASA Technical Reports Server (NTRS)

Otto, S. R.

1993-01-01

The aim of this article is to determine the stability characteristics of a Rayleigh layer, which is known to occur when the fluid above a flat plate has a velocity imparted to it (parallel to the plate). This situation is intrinsically unsteady, however, as a first approximation we consider the instantaneous stability of the flow. The Orr-Sommerfeld equation is found to govern fixed downstream wavelength linear perturbations to the basic flow profile. By the solution of this equation, we can determine the Reynolds numbers at which the flow is neutrally stable; this quasisteady approach is only formally applicable for infinite Reynolds numbers. We shall consider the large Reynolds number limit of the original problem and use a three deck mentality to determine the form of the modes. The results of the two calculations are compared, and the linear large Reynolds number analysis is extended to consider the effect of weak nonlinearity in order to determine whether the system is subcritical or supercritical.

A three-dimensional spectral algorithm for simulations of transition and turbulence

NASA Technical Reports Server (NTRS)

Zang, T. A.; Hussaini, M. Y.

1985-01-01

A spectral algorithm for simulating three dimensional, incompressible, parallel shear flows is described. It applies to the channel, to the parallel boundary layer, and to other shear flows with one wall bounded and two periodic directions. Representative applications to the channel and to the heated boundary layer are presented.

Topical Structure in Argumentative Essays of EFL Learners and Implications for Writing Classes

ERIC Educational Resources Information Center

Kiliç, Mehmet; Genç, Bilal; Bada, Erdogan

2016-01-01

The literature on the topical organization of essays suggests that there are four possible types of progression from the topic of one clause to the topics of the following clauses. These are parallel, sequential, extended parallel, and extended sequential progressions. Essay writers' ability to create cohesion and coherence can be evaluated on the…

An Inconvenient Truth: An Application of the Extended Parallel Process Model

ERIC Educational Resources Information Center

Goodall, Catherine E.; Roberto, Anthony J.

2008-01-01

"An Inconvenient Truth" is an Academy Award-winning documentary about global warming presented by Al Gore. This documentary is appropriate for a lesson on fear appeals and the extended parallel process model (EPPM). The EPPM is concerned with the effects of perceived threat and efficacy on behavior change. Perceived threat is composed of an…

Using the Extended Parallel Process Model to Examine Teachers' Likelihood of Intervening in Bullying

ERIC Educational Resources Information Center

Duong, Jeffrey; Bradshaw, Catherine P.

2013-01-01

Background: Teachers play a critical role in protecting students from harm in schools, but little is known about their attitudes toward addressing problems like bullying. Previous studies have rarely used theoretical frameworks, making it difficult to advance this area of research. Using the Extended Parallel Process Model (EPPM), we examined the…

75 FR 73128 - Certain Printing and Imaging Devices and Components Thereof; Notice of Commission Determination...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-29

...'' include any line extending parallel to the central axis of the roller? Or, does this refer to the central... ``a longitudinal direction'' can include any line extending parallel to the central axis of the roller...) The finding that the Taylor reference (``A Telerobot on the World Wide Web'') (RX-281) does not...

Strongly nonlinear dynamics of electrolytes in large ac voltages.

PubMed

Højgaard Olesen, Laurits; Bazant, Martin Z; Bruus, Henrik

2010-07-01

We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider the simplest possible model of a symmetric binary electrolyte confined between parallel-plate blocking electrodes, ignoring any transverse instability or fluid flow. We analyze the resulting one-dimensional problem by matched asymptotic expansions in the limit of thin double layers and extend previous work into the strongly nonlinear regime, which is characterized by two features--significant salt depletion in the electrolyte near the electrodes and, at very large voltage, the breakdown of the quasiequilibrium structure of the double layers. The former leads to the prediction of "ac capacitive desalination" since there is a time-averaged transfer of salt from the bulk to the double layers, via oscillating diffusion layers. The latter is associated with transient diffusion limitation, which drives the formation and collapse of space-charge layers, even in the absence of any net Faradaic current through the cell. We also predict that steric effects of finite ion sizes (going beyond dilute-solution theory) act to suppress the strongly nonlinear regime in the limit of concentrated electrolytes, ionic liquids, and molten salts. Beyond the model problem, our reduced equations for thin double layers, based on uniformly valid matched asymptotic expansions, provide a useful mathematical framework to describe additional nonlinear responses to large ac voltages, such as Faradaic reactions, electro-osmotic instabilities, and induced-charge electrokinetic phenomena.

Transparent magnetic state in single crystal Nd(1.85)Ce(0.15)CuO(4-y) superconductors

NASA Technical Reports Server (NTRS)

Zuo, F.

1995-01-01

Several experimental studies have been reported as evidence of Josephson coupling between the superconducting layers in the highly anisotropic oxide such as the Bi2Sr2CaCu2O8 and Tl2Ba2CuO6 systems. These include the large penetration depth of 100 mu m measured, ac and dc Josephson effects. Recently two critical temperatures corresponding to Josephson coupling in between the layers and the Berezinskii-Kosterlitz-Thouless transition in the ab-plane have been directly observed in the transport measurements. If the field is applied parallel to the superconducting layers, the magnetic excitation is not the conventional Abrikosov vortices, but the Josephson vortices which extend lambda(sub ab) in the c-axis direction and lambda(sub J) = gamma s in the plane (s is the interlayer distance, gamma is the anisotropy constant). Because of the weak screening effect associated with the Josephson vortices, there have been predictions of magnetic transparent states at magnetic field above a characteristic field H(sub J), a behavior distinctively different from that of the type-II superconductors. In this paper, we report an experimental result which illustrates a transition from the Meissner state to the magnetic transparent state in single crystal of Nd(1.85)Ce(0.15)CuO(4-y). Magnetization has been measured as a function of temperature and field in the magnetic field parallel or close to ab-plane geometry. For a fixed magnetic field, the magnetization shows a two-step transition in M(T); for a fixed temperature, the magnetization shows an abrupt change to almost zero value above a characteristic field H(sub J), an indication of magnetic transparent state. The data of magnetization as a function of field clearly deviates from the behavior predicted by the Abrikosov theory for type-II superconductors. Instead, the data fit well into the picture of Josephson decoupling between the CuO2 layers.

Armor structures

DOEpatents

Chu, Henry Shiu-Hung [Idaho Falls, ID; Lacy, Jeffrey M [Idaho Falls, ID

2008-04-01

An armor structure includes first and second layers individually containing a plurality of i-beams. Individual i-beams have a pair of longitudinal flanges interconnected by a longitudinal crosspiece and defining opposing longitudinal channels between the pair of flanges. The i-beams within individual of the first and second layers run parallel. The laterally outermost faces of the flanges of adjacent i-beams face one another. One of the longitudinal channels in each of the first and second layers faces one of the longitudinal channels in the other of the first and second layers. The channels of the first layer run parallel with the channels of the second layer. The flanges of the first and second layers overlap with the crosspieces of the other of the first and second layers, and portions of said flanges are received within the facing channels of the i-beams of the other of the first and second layers.

Sustainability Attitudes and Behavioral Motivations of College Students: Testing the Extended Parallel Process Model

ERIC Educational Resources Information Center

Perrault, Evan K.; Clark, Scott K.

2018-01-01

Purpose: A planet that can no longer sustain life is a frightening thought--and one that is often present in mass media messages. Therefore, this study aims to test the components of a classic fear appeal theory, the extended parallel process model (EPPM) and to determine how well its constructs predict sustainability behavioral intentions. This…

Supramolecular hydrogen-bonding networks in bis(adeninium) phthalate phthalic acid 1.45-hydrate.

PubMed

Sridhar, Balasubramanian; Ravikumar, Krishnan

2007-04-01

In the title compound, 2C(5)H(6)N(5)(+).C(8)H(4)O(4)(2-).C(8)H(6)O(4).1.45H(2)O, the asymmetric unit comprises two adeninium cations, two half phthalate anions with crystallographic C(2) symmetry, one neutral phthalic acid molecule, and one fully occupied and one partially occupied site (0.45) for water molecules. The adeninium cations form N-H...O hydrogen bonds with the phthalate anions. The cations also form infinite one-dimensional polymeric ribbons via N-H...N interactions. In the crystal packing, hydrogen-bonded columns of cations, anions and phthalate anions extend parallel to the c axis. The water molecules crosslink adjacent columns into hydrogen-bonded layers.

The role of HiPPI switches in mass storage systems: A five year prospective

NASA Technical Reports Server (NTRS)

Gilbert, T. A.

1992-01-01

New standards are evolving which provide the foundation for novel multi-gigabit per second data communication structures. The lowest layer protocols are so generalized that they encourage a wide range of application. Specifically, the ANSI High Performance Parallel Interface (HiPPI) is being applied to computer peripheral attachment as well as general data communication networks. This paper introduces the HiPPI standards suite and technology products which incorporate the standards. The use of simple HiPPI crosspoint switches to build potentially complex extended 'fabrics' is discussed in detail. Several near term applications of the HiPPI technology are briefly described with additional attention to storage systems. Finally, some related standards are mentioned which may further expand the concepts above.

The role of HiPPI switches in mass storage systems: A five year prospective

NASA Technical Reports Server (NTRS)

Gilbert, T. A.

1991-01-01

New standards are evolving which provide the foundation for multi-gigabit per second data communication structures. The lowest layer protocols are so generalized that they encourage a wide range of application. Specifically, the ANSI High Performance Parallel Interface (HiPPI) is being applied to computer peripheral attachment as well as general data communication networks. The HiPPI Standards suite and technology products which incorporate the standards are introduced. The use of simple HiPPI crosspoint switches to build potentially complex extended 'fabrics' is discussed in detail. Several near term applications of the HiPPI technology are briefly described with additional attention to storage systems. Finally, some related standards are mentioned which may further expand the concepts above.

Theory of energy and power flow of plasmonic waves on single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Moradi, Afshin

2017-10-01

The energy theorem of electrodynamics is extended so as to apply to the plasmonic waves on single-walled carbon nanotubes which propagate parallel to the axial direction of the system and are periodic waves in the azimuthal direction. Electronic excitations on the nanotube surface are modeled by an infinitesimally thin layer of free-electron gas which is described by means of the linearized hydrodynamic theory. General expressions of energy and power flow associated with surface waves are obtained by solving Maxwell and hydrodynamic equations with appropriate boundary conditions. Numerical results for the transverse magnetic mode show that energy, power flow, and energy transport velocity of the plasmonic waves strongly depend on the nanotube radius in the long-wavelength region.

Photonics and other approaches to high speed communications

NASA Technical Reports Server (NTRS)

Maly, Kurt

1992-01-01

Our research group of 4 faculty and about 10-15 graduate students was actively involved (as a group) in the development of computer communication networks for the last five years. Many of its individuals have been involved in related research for a much longer period. The overall research goal is to extend network performance to higher data rates, to improve protocol performance at most ISO layers and to improve network operational performance. We briefly state our research goals, then discuss the research accomplishments and direct your attention to attached and/or published papers which cover the following topics: scalable parallel communications; high performance interconnection between high data rate networks; and a simple, effective media access protocol system for integrated, high data rate networks.

Resonance line transfer calculations by doubling thin layers. I - Comparison with other techniques. II - The use of the R-parallel redistribution function. [planetary atmospheres

NASA Technical Reports Server (NTRS)

Yelle, Roger V.; Wallace, Lloyd

1989-01-01

A versatile and efficient technique for the solution of the resonance line scattering problem with frequency redistribution in planetary atmospheres is introduced. Similar to the doubling approach commonly used in monochromatic scattering problems, the technique has been extended to include the frequency dependence of the radiation field. Methods for solving problems with external or internal sources and coupled spectral lines are presented, along with comparison of some sample calculations with results from Monte Carlo and Feautrier techniques. The doubling technique has also been applied to the solution of resonance line scattering problems where the R-parallel redistribution function is appropriate, both neglecting and including polarization as developed by Yelle and Wallace (1989). With the constraint that the atmosphere is illuminated from the zenith, the only difficulty of consequence is that of performing precise frequency integrations over the line profiles. With that problem solved, it is no longer necessary to use the Monte Carlo method to solve this class of problem.

Embedded cluster metal-polymeric micro interface and process for producing the same

DOEpatents

Menezes, Marlon E.; Birnbaum, Howard K.; Robertson, Ian M.

2002-01-29

A micro interface between a polymeric layer and a metal layer includes isolated clusters of metal partially embedded in the polymeric layer. The exposed portion of the clusters is smaller than embedded portions, so that a cross section, taken parallel to the interface, of an exposed portion of an individual cluster is smaller than a cross section, taken parallel to the interface, of an embedded portion of the individual cluster. At least half, but not all of the height of a preferred spherical cluster is embedded. The metal layer is completed by a continuous layer of metal bonded to the exposed portions of the discontinuous clusters. The micro interface is formed by heating a polymeric layer to a temperature, near its glass transition temperature, sufficient to allow penetration of the layer by metal clusters, after isolated clusters have been deposited on the layer at lower temperatures. The layer is recooled after embedding, and a continuous metal layer is deposited upon the polymeric layer to bond with the discontinuous metal clusters.

Implementation of a 3D mixing layer code on parallel computers

NASA Technical Reports Server (NTRS)

Roe, K.; Thakur, R.; Dang, T.; Bogucz, E.

1995-01-01

This paper summarizes our progress and experience in the development of a Computational-Fluid-Dynamics code on parallel computers to simulate three-dimensional spatially-developing mixing layers. In this initial study, the three-dimensional time-dependent Euler equations are solved using a finite-volume explicit time-marching algorithm. The code was first programmed in Fortran 77 for sequential computers. The code was then converted for use on parallel computers using the conventional message-passing technique, while we have not been able to compile the code with the present version of HPF compilers.

Formative Research regarding Kidney Disease Health Information in a Latino American Sample: Associations among Message Frame, Threat, Efficacy, Message Effectiveness, and Behavioral Intention

ERIC Educational Resources Information Center

Maguire, Katheryn C.; Gardner, Jay; Sopory, Pradeep; Jian, Guowei; Roach, Marcia; Amschlinger, Joe; Moreno, Marcia; Pettey, Gary; Piccone, Gianfranco

2010-01-01

Using prospect theory and the extended parallel process model, this study examined the effect of gain/loss message framing on perceptions of severity, susceptibility, response efficacy, and self efficacy (derived from the extended parallel process model), as well as perception of message effectiveness and behavioral intention in a community based…

Simulation of the lunar surface emission and inversion of the lunar regolith thickness using fusion of optical and microwave remote sensing data

NASA Astrophysics Data System (ADS)

Jin, Y.-Q.

begin table htbp begin center begin tabular p 442pt hline A correspondence of the lunar regolith layer thickness to the lunar digital elevation mapping DEM is presented to construct the global distribution of lunar regolith layer thickness Based on some measurements the physical temperature distribution over the lunar surface is proposed Albedo of the lunar nearside at the wavelengths 0 42 0 65 0 75 0 95 mu m from the telescopic observation is employed to construct the spatial distribution of the FeO TiO 2 on the lunar regolith layer A statistic relationship between the DEM and FeO TiO 2 content of the lunar nearside is then extended to construction of FeO TiO 2 content of the lunar farside Thus the dielectric permittivity of global lunar regolith layer can be determined par Based on all theses conditions brightness temperature of the lunar regolith layer in passive microwave remote sensing which is planned for China s Chang-E lunar project is numerically simulated by a parallel layer model using the fluctuation dissipation theorem par Furthermore taking these simulations as observations an inversion method of the lunar regolith layer thickness is developed by using three- or two-channels brightness temperatures When the FeO TiO 2 content is low and the four channels brightness temperatures in Chang-E project are well distinguishable the regolith layer thickness and physical temperature of the underlying lunar rocky media can be inverted by the three-channels approach When the FeO TiO 2 content is so high that the

Two-axis magnetic field sensor

NASA Technical Reports Server (NTRS)

Smith, Carl H. (Inventor); Nordman, Catherine A. (Inventor); Jander, Albrecht (Inventor); Qian, Zhenghong (Inventor)

2006-01-01

A ferromagnetic thin-film based magnetic field sensor with first and second sensitive direction sensing structures each having a nonmagnetic intermediate layer with two major surfaces on opposite sides thereof having a magnetization reference layer on one and an anisotropic ferromagnetic material sensing layer on the other having a length in a selected length direction and a smaller width perpendicular thereto and parallel to the relatively fixed magnetization direction. The relatively fixed magnetization direction of said magnetization reference layer in each is oriented in substantially parallel to the substrate but substantially perpendicular to that of the other. An annealing process is used to form the desired magnetization directions.

Steady Boundary Layer Disturbances Created By Two-Dimensional Surface Ripples

NASA Astrophysics Data System (ADS)

Kuester, Matthew

2017-11-01

Multiple experiments have shown that surface roughness can enhance the growth of Tollmien-Schlichting (T-S) waves in a laminar boundary layer. One of the common observations from these studies is a ``wall displacement'' effect, where the boundary layer profile shape remains relatively unchanged, but the origin of the profile pushes away from the wall. The objective of this work is to calculate the steady velocity field (including this wall displacement) of a laminar boundary layer over a surface with small, 2D surface ripples. The velocity field is a combination of a Blasius boundary layer and multiple disturbance modes, calculated using the linearized Navier-Stokes equations. The method of multiple scales is used to include non-parallel boundary layer effects of O (Rδ- 1) ; the non-parallel terms are necessary, because a wall displacement is mathematically inconsistent with a parallel boundary layer assumption. This technique is used to calculate the steady velocity field over ripples of varying height and wavelength, including cases where a separation bubble forms on the leeward side of the ripple. In future work, the steady velocity field will be the input for stability calculations, which will quantify the growth of T-S waves over rough surfaces. The author would like to acknowledge the support of the Kevin T. Crofton Aerospace & Ocean Engineering Department at Virginia Tech.

Thouless length and valley degeneracy factor of ZnMnO thin films with anisotropic, highly conductive surface layers

NASA Astrophysics Data System (ADS)

Vegesna, Sahitya V.; Bürger, Danilo; Patra, Rajkumar; Abendroth, Barbara; Skorupa, Ilona; Schmidt, Oliver G.; Schmidt, Heidemarie

2017-06-01

Isothermal magnetoresistance (MR) of n-type conducting Zn1-xMnxO thin films on a sapphire substrate with a Mn content of 5 at. % has been studied in in-plane and out-of-plane magnetic fields up to 6 T in the temperature range of 5 K to 300 K. During pulsed laser deposition of the ZnMnO thin films, we controlled the thickness and roughness of a highly conductive ZnMnO surface layer. The measured MR has been modeled with constant s-d exchange (0.2 eV in ZnMnO) and electron spin (S = 5/2 for Mn2+) for samples with a single two dimensional (2D) ZnMnO layer, a single three dimensional (3D) ZnMnO layer, or a 2D and 3D (2D + 3D) ZnMnO layer in parallel. The temperature dependence of modeled Thouless length LTh (LTh ˜ T-0.5) is in good agreement with the theory [Andrearczyk et al., Phys. Rev. B 72, 121309(R) (2005)]. The superimposed positive and negative MR model for ZnCoO thin films [Xu et al., Phys. Rev. B 76, 134417 (2007)] has been extended in order to account for the increase in the density of states close to the Fermi level of n-ZnMnO due to substitutional Mn2+ ions and their effect on the negative MR in ZnMnO.

Extraction of Ice Sheet Layers from Two Intersected Radar Echograms Near Neem Ice Core in Greenland

NASA Astrophysics Data System (ADS)

Xiong, S.; Muller, J.-P.

2016-06-01

Accumulation of snow and ice over time result in ice sheet layers. These can be remotely sensed where there is a contrast in electromagnetic properties, which reflect variations of the ice density, acidity and fabric orientation. Internal ice layers are assumed to be isochronous, deep beneath the ice surface, and parallel to the direction of ice flow. The distribution of internal layers is related to ice sheet dynamics, such as the basal melt rate, basal elevation variation and changes in ice flow mode, which are important parameters to model the ice sheet. Radar echo sounder is an effective instrument used to study the sedimentology of the Earth and planets. Ice Penetrating Radar (IPR) is specific kind of radar echo sounder, which extends studies of ice sheets from surface to subsurface to deep internal ice sheets depending on the frequency utilised. In this study, we examine a study site where folded ice occurs in the internal ice sheet south of the North Greenland Eemian ice drilling (NEEM) station, where two intersected radar echograms acquired by the Multi-channel Coherent Radar Depth Sounder (MCoRDS) employed in the NASA's Operation IceBridge (OIB) mission imaged this folded ice. We propose a slice processing flow based on a Radon Transform to trace and extract these two sets of curved ice sheet layers, which can then be viewed in 3-D, demonstrating the 3-D structure of the ice folds.

Correlation between surface morphology and surface forces of protein A adsorbed on mica.

PubMed Central

Ohnishi, S; Murata, M; Hato, M

1998-01-01

We have investigated the morphology and surface forces of protein A adsorbed on mica surface in the protein solutions of various concentrations. The force-distance curves, measured with a surface force apparatus (SFA), were interpreted in terms of two different regimens: a "large-distance" regimen in which an electrostatic double-layer force dominates, and an "adsorbed layer" regimen in which a force of steric origin dominates. To further clarify the forces of steric origin, the surface morphology of the adsorbed protein layer was investigated with an atomic force microscope (AFM) because the steric repulsive forces are strongly affected by the adsorption mode of protein A molecules on mica. At lower protein concentrations (2 ppm, 10 ppm), protein A molecules were adsorbed "side-on" parallel to the mica surfaces, forming a monolayer of approximately 2.5 nm. AFM images at higher concentrations (30 ppm, 100 ppm) showed protruding structures over the monolayer, which revealed that the adsorbed protein A molecules had one end oriented into the solution, with the remainder of each molecule adsorbed side-on to the mica surface. These extending ends of protein A overlapped each other and formed a "quasi-double layer" over the mica surface. These AFM images proved the existence of a monolayer of protein A molecules at low concentrations and a "quasi-double layer" with occasional protrusions at high concentrations, which were consistent with the adsorption mode observed in the force-distance curves. PMID:9449346

Multilayer insulation blanket, fabricating apparatus and method

DOEpatents

Gonczy, John D.; Niemann, Ralph C.; Boroski, William N.

1992-01-01

An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel.

Method of fabricating a multilayer insulation blanket

DOEpatents

Gonczy, John D.; Niemann, Ralph C.; Boroski, William N.

1993-01-01

An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel.

Method of fabricating a multilayer insulation blanket

DOEpatents

Gonczy, J.D.; Niemann, R.C.; Boroski, W.N.

1993-07-06

An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel.

Multilayer insulation blanket, fabricating apparatus and method

DOEpatents

Gonczy, J.D.; Niemann, R.C.; Boroski, W.N.

1992-09-01

An improved multilayer insulation blanket for insulating cryogenic structures operating at very low temperatures is disclosed. An apparatus and method for fabricating the improved blanket are also disclosed. In the improved blanket, each successive layer of insulating material is greater in length and width than the preceding layer so as to accommodate thermal contraction of the layers closest to the cryogenic structure. The fabricating apparatus has a rotatable cylindrical mandrel having an outer surface of fixed radius that is substantially arcuate, preferably convex, in cross-section. The method of fabricating the improved blanket comprises (a) winding a continuous sheet of thermally reflective material around the circumference of the mandrel to form multiple layers, (b) binding the layers along two lines substantially parallel to the edges of the circumference of the mandrel, (c) cutting the layers along a line parallel to the axle of the mandrel, and (d) removing the bound layers from the mandrel. 7 figs.

Modeling interface shear behavior of granular materials using micro-polar continuum approach

NASA Astrophysics Data System (ADS)

Ebrahimian, Babak; Noorzad, Ali; Alsaleh, Mustafa I.

2018-01-01

Recently, the authors have focused on the shear behavior of interface between granular soil body and very rough surface of moving bounding structure. For this purpose, they have used finite element method and a micro-polar elasto-plastic continuum model. They have shown that the boundary conditions assumed along the interface have strong influences on the soil behavior. While in the previous studies, only very rough bounding interfaces have been taken into account, the present investigation focuses on the rough, medium rough and relatively smooth interfaces. In this regard, plane monotonic shearing of an infinite extended narrow granular soil layer is simulated under constant vertical pressure and free dilatancy. The soil layer is located between two parallel rigid boundaries of different surface roughness values. Particular attention is paid to the effect of surface roughness of top and bottom boundaries on the shear behavior of granular soil layer. It is shown that the interaction between roughness of bounding structure surface and the rotation resistance of bounding grains can be modeled in a reasonable manner through considered Cosserat boundary conditions. The influence of surface roughness is investigated on the soil shear strength mobilized along the interface as well as on the location and evolution of shear localization formed within the layer. The obtained numerical results have been qualitatively compared with experimental observations as well as DEM simulations, and acceptable agreement is shown.

Collisionless slow shocks in magnetotail reconnection

NASA Astrophysics Data System (ADS)

Cremer, Michael; Scholer, Manfred

The kinetic structure of collisionless slow shocks in the magnetotail is studied by solving the Riemann problem of the collapse of a current sheet with a normal magnetic field component using 2-D hybrid simulations. The collapse results in a current layer with a hot isotropic distribution and backstreaming ions in a boundary layer. The lobe plasma outside and within the boundary layer exhibits a large perpendicular to parallel temperature anisotropy. Waves in both regions propagate parallel to the magnetic field. In a second experiment a spatially limited high density beam is injected into a low beta background plasma and the subsequent wave excitation is studied. A model for slow shocks bounding the reconnection layer in the magnetotail is proposed where backstreaming ions first excite obliquely propagating waves by the electromagnetic ion/ion cyclotron instability, which lead to perpendicular heating. The T⊥/T∥ temperature anisotropy subsequently excites parallel propagating Alfvén ion cyclotron waves, which are convected into the slow shock and are refracted in the downstream region.

An S3-3 search for confined regions of large parallel electric fields

NASA Astrophysics Data System (ADS)

Boehm, M. H.; Mozer, F. S.

1981-06-01

S3-3 satellite passes through several hundred perpendicular shocks are searched for evidence of large, mostly parallel electric fields (several hundred millivolts per meter, total potential of several kilo-volts) in the auroral zone magnetosphere at altitudes of several thousand kilometers. The actual search criteria are that one or more E-field data points have a parallel component E sub z greater than 350 mV/m in general, or 100 mV/m for data within 10 seconds of a perpendicular shock, since double layers might be likely, in such regions. Only a few marginally convincing examples of the electric fields are found, none of which fits a double layer model well. From statistics done with the most unbiased part of the data set, upper limits are obtained on the number and size of double layers occurring in the auroral zone magnetosphere, and it is concluded that the double layers most probably cannot be responsible for the production of diffuse aurora or inverted-V events.

Large-scale trench-normal mantle flow beneath central South America

NASA Astrophysics Data System (ADS)

Reiss, M. C.; Rümpker, G.; Wölbern, I.

2018-01-01

We investigate the anisotropic properties of the fore-arc region of the central Andean margin between 17-25°S by analyzing shear-wave splitting from teleseismic and local earthquakes from the Nazca slab. With partly over ten years of recording time, the data set is uniquely suited to address the long-standing debate about the mantle flow field at the South American margin and in particular whether the flow field beneath the slab is parallel or perpendicular to the trench. Our measurements suggest two anisotropic layers located within the crust and mantle beneath the stations, respectively. The teleseismic measurements show a moderate change of fast polarizations from North to South along the trench ranging from parallel to subparallel to the absolute plate motion and, are oriented mostly perpendicular to the trench. Shear-wave splitting measurements from local earthquakes show fast polarizations roughly aligned trench-parallel but exhibit short-scale variations which are indicative of a relatively shallow origin. Comparisons between fast polarization directions from local earthquakes and the strike of the local fault systems yield a good agreement. To infer the parameters of the lower anisotropic layer we employ an inversion of the teleseismic waveforms based on two-layer models, where the anisotropy of the upper (crustal) layer is constrained by the results from the local splitting. The waveform inversion yields a mantle layer that is best characterized by a fast axis parallel to the absolute plate motion which is more-or-less perpendicular to the trench. This orientation is likely caused by a combination of the fossil crystallographic preferred orientation of olivine within the slab and entrained mantle flow beneath the slab. The anisotropy within the crust of the overriding continental plate is explained by the shape-preferred orientation of micro-cracks in relation to local fault zones which are oriented parallel to the overall strike of the Andean range. Our results do not provide any evidence for a significant contribution of trench-parallel mantle flow beneath the subducting slab.

A comparison of energetic ions in the plasma depletion layer and the quasi-parallel magnetosheath

NASA Technical Reports Server (NTRS)

Fuselier, Stephen A.

1994-01-01

Energetic ion spectra measured by the Active Magnetospheric Particle Tracer Explorers/Charge Composition Explorer (AMPTE/CCE) downstream from the Earth's quasi-parallel bow shock (in the quasi-parallel magnetosheath) and in the plasma depletion layer are compared. In the latter region, energetic ions are from a single source, leakage of magnetospheric ions across the magnetopause and into the plasma depletion layer. In the former region, both the magnetospheric source and shock acceleration of the thermal solar wind population at the quasi-parallel shock can contribute to the energetic ion spectra. The relative strengths of these two energetic ion sources are determined through the comparison of spectra from the two regions. It is found that magnetospheric leakage can provide an upper limit of 35% of the total energetic H(+) population in the quasi-parallel magnetosheath near the magnetopause in the energy range from approximately 10 to approximately 80 keV/e and substantially less than this limit for the energetic He(2+) population. The rest of the energetic H(+) population and nearly all of the energetic He(2+) population are accelerated out of the thermal solar wind population through shock acceleration processes. By comparing the energetic and thermal He(2+) and H(+) populations in the quasi-parallel magnetosheath, it is found that the quasi-parallel bow shock is 2 to 3 times more efficient at accelerating He(2+) than H(+). This result is consistent with previous estimates from shock acceleration theory and simulati ons.

Ontogeny of the sheathing leaf base in maize (Zea mays).

PubMed

Johnston, Robyn; Leiboff, Samuel; Scanlon, Michael J

2015-01-01

Leaves develop from the shoot apical meristem (SAM) via recruitment of leaf founder cells. Unlike eudicots, most monocot leaves display parallel venation and sheathing bases wherein the margins overlap the stem. Here we utilized computed tomography (CT) imaging, localization of PIN-FORMED1 (PIN1) auxin transport proteins, and in situ hybridization of leaf developmental transcripts to analyze the ontogeny of monocot leaf morphology in maize (Zea mays). CT imaging of whole-mounted shoot apices illustrates the plastochron-specific stages during initiation of the basal sheath margins from the tubular disc of insertion (DOI). PIN1 localizations identify basipetal auxin transport in the SAM L1 layer at the site of leaf initiation, a process that continues reiteratively during later recruitment of lateral leaf domains. Refinement of these auxin transport domains results in multiple, parallel provascular strands within the initiating primordium. By contrast, auxin is transported from the L2 toward the L1 at the developing margins of the leaf sheath. Transcripts involved in organ boundary formation and dorsiventral patterning accumulate within the DOI, preceding the outgrowth of the overlapping margins of the sheathing leaf base. We suggest a model wherein sheathing bases and parallel veins are both patterned via the extended recruitment of lateral maize leaf domains from the SAM. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Magnetospheric Multiscale Satellites Observations of Parallel Electric Fields Associated with Magnetic Reconnection

NASA Technical Reports Server (NTRS)

Ergun, R. E.; Goodrich, K. A.; Wilder, F. D.; Holmes, J. C.; Stawarz, J. E.; Eriksson, S.; Sturner, A. P.; Malaspina, D. M.; Usanova, M. E.; Torbert, R. B.;

The structure of denisovite, a fibrous nanocrystalline polytypic disordered ‘very complex’ silicate, studied by a synergistic multi-disciplinary approach employing methods of electron crystallography and X-ray powder diffraction

PubMed Central

Schowalter, Marco; Schmidt, Martin U.; Czank, Michael; Depmeier, Wulf; Rosenauer, Andreas

2017-01-01

Denisovite is a rare mineral occurring as aggregates of fibres typically 200–500 nm diameter. It was confirmed as a new mineral in 1984, but important facts about its chemical formula, lattice parameters, symmetry and structure have remained incompletely known since then. Recently obtained results from studies using microprobe analysis, X-ray powder diffraction (XRPD), electron crystallography, modelling and Rietveld refinement will be reported. The electron crystallography methods include transmission electron microscopy (TEM), selected-area electron diffraction (SAED), high-angle annular dark-field imaging (HAADF), high-resolution transmission electron microscopy (HRTEM), precession electron diffraction (PED) and electron diffraction tomography (EDT). A structural model of denisovite was developed from HAADF images and later completed on the basis of quasi-kinematic EDT data by ab initio structure solution using direct methods and least-squares refinement. The model was confirmed by Rietveld refinement. The lattice parameters are a = 31.024 (1), b = 19.554 (1) and c = 7.1441 (5) Å, β = 95.99 (3)°, V = 4310.1 (5) Å3 and space group P12/a1. The structure consists of three topologically distinct dreier silicate chains, viz. two xonotlite-like dreier double chains, [Si6O17]10−, and a tubular loop-branched dreier triple chain, [Si12O30]12−. The silicate chains occur between three walls of edge-sharing (Ca,Na) octahedra. The chains of silicate tetrahedra and the octahedra walls extend parallel to the z axis and form a layer parallel to (100). Water molecules and K+ cations are located at the centre of the tubular silicate chain. The latter also occupy positions close to the centres of eight-membered rings in the silicate chains. The silicate chains are geometrically constrained by neighbouring octahedra walls and present an ambiguity with respect to their z position along these walls, with displacements between neighbouring layers being either Δz = c/4 or −c/4. Such behaviour is typical for polytypic sequences and leads to disorder along [100]. In fact, the diffraction pattern does not show any sharp reflections with l odd, but continuous diffuse streaks parallel to a* instead. Only reflections with l even are sharp. The diffuse scattering is caused by (100) nano­lamellae separated by stacking faults and twin boundaries. The structure can be described according to the order–disorder (OD) theory as a stacking of layers parallel to (100). PMID:28512570

Message-passing-interface-based parallel FDTD investigation on the EM scattering from a 1-D rough sea surface using uniaxial perfectly matched layer absorbing boundary.

PubMed

Li, J; Guo, L-X; Zeng, H; Han, X-B

2009-06-01

A message-passing-interface (MPI)-based parallel finite-difference time-domain (FDTD) algorithm for the electromagnetic scattering from a 1-D randomly rough sea surface is presented. The uniaxial perfectly matched layer (UPML) medium is adopted for truncation of FDTD lattices, in which the finite-difference equations can be used for the total computation domain by properly choosing the uniaxial parameters. This makes the parallel FDTD algorithm easier to implement. The parallel performance with different processors is illustrated for one sea surface realization, and the computation time of the parallel FDTD algorithm is dramatically reduced compared to a single-process implementation. Finally, some numerical results are shown, including the backscattering characteristics of sea surface for different polarization and the bistatic scattering from a sea surface with large incident angle and large wind speed.

The light wave flow effect in a plane-parallel layer with a quasi-zero refractive index under the action of bounded light beams

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

Gadomsky, O. N., E-mail: gadomsky@mail.ru; Shchukarev, I. A., E-mail: blacxpress@gmail.com

2016-08-15

It is shown that external optical radiation in the 450–1200 nm range can be efficiently transformed under the action of bounded light beams to a surface wave that propagates along the external and internal boundaries of a plane-parallel layer with a quasi-zero refractive index. Reflection regimes with complex and real angles of refraction in the layer are considered. The layer with a quasi-zero refractive index in this boundary problem is located on a highly reflective metal substrate; it is shown that the uniform low reflection of light is achieved in the wavelength range under study.

Real-time SHVC software decoding with multi-threaded parallel processing

NASA Astrophysics Data System (ADS)

Gudumasu, Srinivas; He, Yuwen; Ye, Yan; He, Yong; Ryu, Eun-Seok; Dong, Jie; Xiu, Xiaoyu

2014-09-01

This paper proposes a parallel decoding framework for scalable HEVC (SHVC). Various optimization technologies are implemented on the basis of SHVC reference software SHM-2.0 to achieve real-time decoding speed for the two layer spatial scalability configuration. SHVC decoder complexity is analyzed with profiling information. The decoding process at each layer and the up-sampling process are designed in parallel and scheduled by a high level application task manager. Within each layer, multi-threaded decoding is applied to accelerate the layer decoding speed. Entropy decoding, reconstruction, and in-loop processing are pipeline designed with multiple threads based on groups of coding tree units (CTU). A group of CTUs is treated as a processing unit in each pipeline stage to achieve a better trade-off between parallelism and synchronization. Motion compensation, inverse quantization, and inverse transform modules are further optimized with SSE4 SIMD instructions. Simulations on a desktop with an Intel i7 processor 2600 running at 3.4 GHz show that the parallel SHVC software decoder is able to decode 1080p spatial 2x at up to 60 fps (frames per second) and 1080p spatial 1.5x at up to 50 fps for those bitstreams generated with SHVC common test conditions in the JCT-VC standardization group. The decoding performance at various bitrates with different optimization technologies and different numbers of threads are compared in terms of decoding speed and resource usage, including processor and memory.

Further development of imaging near-field scatterometer

NASA Astrophysics Data System (ADS)

Uebeler, Denise; Pescoller, Lukas; Hahlweg, Cornelius

2015-09-01

In continuation of last year's paper on the use of near field imaging, which basically is a reflective shadowgraph method, for characterization of glossy surfaces like printed matter or laminated material, further developments are discussed. Beside the identification of several types of surfaces and related features, for which the method is applicable, several refinements are introduced. The theory of the method is extended, based on a mixed Fourier optical and geometrical approach, leading to rules of thumb for the resolution to be expected, giving a framework for design. Further, a refined experimental set-up is introduced. Variation of plane of focus and incident angle are used for separation of various the images of he layers of the surface under test, cross and parallel polarization techniques are applied. Finally, exemplary measurement results and examples are included.

Crystal structure of 2-(1,3-dioxoindan-2-yl)iso-quinoline-1,3,4-trione.

PubMed

Ghalib, Raza Murad; Chidan Kumar, C S; Hashim, Rokiah; Sulaiman, Othman; Fun, Hoong-Kun

2015-01-01

In the title iso-quinoline-1,3,4-trione derivative, C18H9NO5, the five-membered ring of the indane fragment adopts an envelope conformation with the nitro-gen-substituted C atom being the flap. The planes of the indane benzene ring and the iso-quinoline-1,3,4-trione ring make a dihedral angle of 82.06 (6)°. In the crystal, mol-ecules are linked into chains extending along the bc plane via C-H⋯O hydrogen-bonding inter-actions, enclosing R 2 (2)(8) and R 2 (2)(10) loops. The chains are further connected by π-π stacking inter-ations, with centroid-to-centroid distances of 3.9050 (7) Å, forming layers parallel to the b axis.

Nonlinear Diamagnetic Stabilization of Double Tearing Modes in Cylindrical MHD Simulations

NASA Astrophysics Data System (ADS)

Abbott, Stephen; Germaschewski, Kai

2014-10-01

Double tearing modes (DTMs) may occur in reversed-shear tokamak configurations if two nearby rational surfaces couple and begin reconnecting. During the DTM's nonlinear evolution it can enter an ``explosive'' growth phase leading to complete reconnection, making it a possible driver for off-axis sawtooth crashes. Motivated by similarities between this behavior and that of the m = 1 kink-tearing mode in conventional tokamaks we investigate diamagnetic drifts as a possible DTM stabilization mechanism. We extend our previous linear studies of an m = 2 , n = 1 DTM in cylindrical geometry to the fully nonlinear regime using the MHD code MRC-3D. A pressure gradient similar to observed ITB profiles is used, together with Hall physics, to introduce ω* effects. We find the diamagnetic drifts can have a stabilizing effect on the nonlinear DTM through a combination of large scale differential rotation and mechanisms local to the reconnection layer. MRC-3D is an extended MHD code based on the libMRC computational framework. It supports nonuniform grids in curvilinear coordinates with parallel implicit and explicit time integration.

Nanoscale lamellar photoconductor hybrids and methods of making same

DOEpatents

Stupp, Samuel I; Goldberger, Josh; Sofos, Marina

2013-02-05

An article of manufacture and methods of making same. In one embodiment, the article of manufacture has a plurality of zinc oxide layers substantially in parallel, wherein each zinc oxide layer has a thickness d.sub.1, and a plurality of organic molecule layers substantially in parallel, wherein each organic molecule layer has a thickness d.sub.2 and a plurality of molecules with a functional group that is bindable to zinc ions, wherein for every pair of neighboring zinc oxide layers, one of the plurality of organic molecule layers is positioned in between the pair of neighboring zinc oxide layers to allow the functional groups of the plurality of organic molecules to bind to zinc ions in the neighboring zinc oxide layers to form a lamellar hybrid structure with a geometric periodicity d.sub.1+d.sub.2, and wherein d.sub.1 and d.sub.2 satisfy the relationship of d.sub.1.ltoreq.d.sub.2.ltoreq.3d.sub.1.

Diagnostic system for profiling micro-beams

DOEpatents

Elmer, John W.; Palmer, Todd A.; Teruya, Alan T.; Walton, Chris C.

2007-10-30

An apparatus for characterization of a micro beam comprising a micro modified Faraday cup assembly including a first layer of material, a second layer of material operatively connected to the first layer of material, a third layer of material operatively connected to the second layer of material, and a fourth layer of material operatively connected to the third layer of material. The first layer of material comprises an electrical conducting material and has at least one first layer radial slit extending through the first layer. An electrical ground is connected to the first layer. The second layer of material comprises an insulating material and has at least one second layer radial slit corresponding to the first layer radial slit in the first layer of material. The second layer radial slit extends through the second layer. The third layer of material comprises a conducting material and has at least one third layer radial slit corresponding to the second layer radial slit in the second layer of material. The third layer radial slit extends through the third layer. The fourth layer of material comprises an electrical conducting material but does not have slits. An electrical measuring device is connected to the fourth layer. The micro modified Faraday cup assembly is positioned to be swept by the micro beam.

Mesh-free distributed point source method for modeling viscous fluid motion between disks vibrating at ultrasonic frequency.

PubMed

Wada, Yuji; Kundu, Tribikram; Nakamura, Kentaro

2014-08-01

The distributed point source method (DPSM) is extended to model wave propagation in viscous fluids. Appropriate estimation on attenuation and boundary layer formation due to fluid viscosity is necessary for the ultrasonic devices used for acoustic streaming or ultrasonic levitation. The equations for DPSM modeling in viscous fluids are derived in this paper by decomposing the linearized viscous fluid equations into two components-dilatational and rotational components. By considering complex P- and S-wave numbers, the acoustic fields in viscous fluids can be calculated following similar calculation steps that are used for wave propagation modeling in solids. From the calculations reported the precision of DPSM is found comparable to that of the finite element method (FEM) for a fundamental ultrasonic field problem. The particle velocity parallel to the two bounding surfaces of the viscous fluid layer between two rigid plates (one in motion and one stationary) is calculated. The finite element results agree well with the DPSM results that were generated faster than the transient FEM results.

Boundary-layer mantle flow under the Dead Sea transform fault inferred from seismic anisotropy.

PubMed

Rümpker, Georg; Ryberg, Trond; Bock, Günter

2003-10-02

Lithospheric-scale transform faults play an important role in the dynamics of global plate motion. Near-surface deformation fields for such faults are relatively well documented by satellite geodesy, strain measurements and earthquake source studies, and deeper crustal structure has been imaged by seismic profiling. Relatively little is known, however, about deformation taking place in the subcrustal lithosphere--that is, the width and depth of the region associated with the deformation, the transition between deformed and undeformed lithosphere and the interaction between lithospheric and asthenospheric mantle flow at the plate boundary. Here we present evidence for a narrow, approximately 20-km-wide, subcrustal anisotropic zone of fault-parallel mineral alignment beneath the Dead Sea transform, obtained from an inversion of shear-wave splitting observations along a dense receiver profile. The geometry of this zone and the contrast between distinct anisotropic domains suggest subhorizontal mantle flow within a vertical boundary layer that extends through the entire lithosphere and accommodates the transform motion between the African and Arabian plates within this relatively narrow zone.

Shift-, rotation-, and scale-invariant shape recognition system using an optical Hough transform

NASA Astrophysics Data System (ADS)

Schmid, Volker R.; Bader, Gerhard; Lueder, Ernst H.

1998-02-01

We present a hybrid shape recognition system with an optical Hough transform processor. The features of the Hough space offer a separate cancellation of distortions caused by translations and rotations. Scale invariance is also provided by suitable normalization. The proposed system extends the capabilities of Hough transform based detection from only straight lines to areas bounded by edges. A very compact optical design is achieved by a microlens array processor accepting incoherent light as direct optical input and realizing the computationally expensive connections massively parallel. Our newly developed algorithm extracts rotation and translation invariant normalized patterns of bright spots on a 2D grid. A neural network classifier maps the 2D features via a nonlinear hidden layer onto the classification output vector. We propose initialization of the connection weights according to regions of activity specifically assigned to each neuron in the hidden layer using a competitive network. The presented system is designed for industry inspection applications. Presently we have demonstrated detection of six different machined parts in real-time. Our method yields very promising detection results of more than 96% correctly classified parts.

Light and transmission electron microscopy of the intact interfaces between non-submerged titanium-coated epoxy resin implants and bone or gingiva.

PubMed

Listgarten, M A; Buser, D; Steinemann, S G; Donath, K; Lang, N P; Weber, H P

1992-02-01

This experiment was aimed at studying the intact tissue/implant interface of non-submerged dental implants with a titanium surface. Epoxy-resin replicas were fabricated from 3.05 x 8 mm cylindrical titanium implants with a plasma-sprayed apical portion and a smooth coronal collar. The replicas were coated with a 90-120-nm-thick layer of pure titanium and autoclaved. The coated replicas were inserted as non-submerged endosseous implants in the edentulous premolar region of dog mandibles and allowed to heal for three months. Jaw sections containing the implants were processed for light and electron microscopic study of the intact tissue/implant interface with and without prior demineralization. Gingival connective tissue fibers were closely adapted to the titanium layer, in an orientation more or less parallel to the implant surface. There was no evidence of any fiber insertions into the surface irregularities of the smooth or rough titanium surface. Undemineralized bone was intimately adapted to the titanium surface without any intervening space. In demineralized sections, the collagen fibers of the bone matrix tended to be somewhat thinner and occasionally less densely packed in the vicinity of the implant surface. However, they extended all the way to the titanium surface, without any intervening fibril-free layer.

Experimental Investigation of Compliant Wall Surface Deformation in Turbulent Boundary Layer

NASA Astrophysics Data System (ADS)

Wang, Jin; Agarwal, Karuna; Katz, Joseph

2017-11-01

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

Microstructure anisotropy and its effect on mechanical properties of reduced activation ferritic/martensitic steel fabricated by selective laser melting

NASA Astrophysics Data System (ADS)

Huang, Bo; Zhai, Yutao; Liu, Shaojun; Mao, Xiaodong

2018-03-01

Selective laser melting (SLM) is a promising way for the fabrication of complex reduced activation ferritic/martensitic steel components. The microstructure of the SLM built China low activation martensitic (CLAM) steel plates was observed and analyzed. The hardness, Charpy impact and tensile testing of the specimens in different orientations were performed at room temperature. The results showed that the difference in the mechanical properties was related to the anisotropy in microstructure. The planer unmelted porosity in the interface of the adjacent layers induced opening/tensile mode when the tensile samples parallel to the build direction were tested whereas the samples vertical to the build direction fractured in the shear mode with the grains being sheared in a slant angle. Moreover, the impact absorbed energy (IAE) of all impact specimens was significantly lower than that of the wrought CLAM steel, and the IAE of the samples vertical to the build direction was higher than that of the samples parallel to the build direction. The impact fracture surfaces revealed that the load parallel to the build layers caused laminated tearing among the layers, and the load vertical to the layers induced intergranular fracture across the layers.

Perception of straightness and parallelism with minimal distance information.

PubMed

Rogers, Brian; Naumenko, Olga

2016-07-01

The ability of human observers to judge the straightness and parallelism of extended lines has been a neglected topic of study since von Helmholtz's initial observations 150 years ago. He showed that there were significant misperceptions of the straightness of extended lines seen in the peripheral visual field. The present study focused on the perception of extended lines (spanning 90° visual angle) that were directly fixated in the visual environment of a planetarium where there was only minimal information about the distance to the lines. Observers were asked to vary the curvature of 1 or more lines until they appeared to be straight and/or parallel, ignoring any perceived curvature in depth. When the horizon between the ground and the sky was visible, the results showed that observers' judgements of the straightness of a single line were significantly biased away from the veridical, great circle locations, and towards equal elevation settings. Similar biases can be seen in the jet trails of aircraft flying across the sky and in Rogers and Anstis's new moon illusion (Perception, 42(Abstract supplement) 18, 2013, 2016). The biasing effect of the horizon was much smaller when observers were asked to judge the straightness and parallelism of 2 or more extended lines. We interpret the results as showing that, in the absence of adequate distance information, observers tend to perceive the projected lines as lying on an approximately equidistant, hemispherical surface and that their judgements of straightness and parallelism are based on the perceived separation of the lines superimposed on that surface.

Method and apparatus for adding electrolyte to a fuel cell stack

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

Congdon, J.V.; English, J.G.

1986-06-24

A process is described for adding electrolyte to a fuel cell stack, the stack comprising sheet-like elements defining a plurality of fuel cell units disposed one atop the other in abutting relationship, the units defining a substantially flat, vertically extending face, each unit including a cell comprising a pair of sheet-like spaced apart gas porous electrodes with a porous matrix layer sandwiched therebetween for retaining electrolyte during cell operation, each unit also including a sheet-like substantially non-porous separator, the separator being sandwiched between the cells of adjacent units. The improvement described here consists of: extending at least one of themore » sheet-like elements of each of a plurality of the fuel cell units outwardly from the stack face to define horizontal tabs disposed one above the other; depositing dilute electrolyte directly from electrolyte supply means upon substantially the full length, parallel to the stack face, of at least the uppermost tab, the tabs being constructed and arranged such that at least a portion of the deposited electrolyte cascades from tab to tab and down the face of the stack, the deposited electrolyte being absorbed by capillary action into the elements of the stack, the step of depositing continuing until all of the electrodes and matrix layers of the stack are fully saturated with the dilute electrolyte; and thereafter evaporating liquid from the saturated elements under controlled conditions of humidity and temperature until the stack has a desired electrolyte volume and electrolyte concentration therein.« less

Kinematic analysis of mélange fabrics: examples and applications from the McHugh Complex, Kenai Peninsula, Alaska

NASA Astrophysics Data System (ADS)

Kusky, Timothy M.; Bradley, Dwight C.

1999-12-01

Permian to Cretaceous mélange of the McHugh Complex on the Kenai Peninsula, south-central Alaska includes blocks and belts of graywacke, argillite, limestone, chert, basalt, gabbro, and ultramafic rocks, intruded by a variety of igneous rocks. An oceanic plate stratigraphy is repeated hundreds of times across the map area, but most structures at the outcrop scale extend lithological layering. Strong rheological units occur as blocks within a matrix that flowed around the competent blocks during deformation, forming broken formation and mélange. Deformation was noncoaxial, and disruption of primary layering was a consequence of general strain driven by plate convergence in a relatively narrow zone between the overriding accretionary wedge and the downgoing, generally thinly sedimented oceanic plate. Soft-sediment deformation processes do not appear to have played a major role in the formation of the mélange. A model for deformation at the toe of the wedge is proposed in which layers oriented at low angles to σ1 are contracted in both the brittle and ductile regimes, layers at 30-45° to σ1 are extended in the brittle regime and contracted in the ductile regime, and layers at angles greater than 45° to σ1 are extended in both the brittle and ductile regimes. Imbrication in thrust duplexes occurs at deeper levels within the wedge. Many structures within mélange of the McHugh Complex are asymmetric and record kinematic information consistent with the inferred structural setting in an accretionary wedge. A displacement field for the McHugh Complex on the lower Kenai Peninsula includes three belts: an inboard belt of Late Triassic rocks records west-to-east-directed slip of hanging walls, a central belt of predominantly Early Jurassic rocks records north-south directed displacements, and Early Cretaceous rocks in an outboard belt preserve southwest-northeast directed slip vectors. Although precise ages of accretion are unknown, slip directions are compatible with inferred plate motions during the general time frame of accretion of the McHugh Complex. The slip vectors are interpreted to preserve the convergence directions between the overriding and underriding plates, which became more oblique with time. They are not considered indicative of strain partitioning into belts of orogen-parallel and orogen-perpendicular displacements, because the kinematic data are derived from the earliest preserved structures, whereas fabrics related to strain partitioning would be expected to be superimposed on earlier accretion-related fabrics.

Reduction Characteristics of FM-Band Cross-Talks between Two Parallel Signal Traces on Printed Circuit Boards for Vehicles

NASA Astrophysics Data System (ADS)

Maeno, Tsuyoshi; Ueyama, Hiroya; Iida, Michihira; Fujiwara, Osamu

It is well known that electromagnetic disturbances in vehicle-mounted radios are mainly caused by conducted noise currents flowing through wiring-harnesses from vehicle-mounted printed circuit boards (PCBs) with common ground patterns with slits. To suppress the noise current outflows from the PCBs of this kind, we previously measured noise current outflows from simple two-layer PCBs having two parallel signal traces and different ground patterns with/without slits, which revealed that making slits with open ends on the ground patterns in parallel with the traces can reduce the conducted noise currents. In the present study, with the FDTD simulation, we investigated reduction characteristics of the FM-band cross-talk noise levels between two parallel signal traces for eighteen PCBs, which have different ground patterns with/without slits parallel to the traces and dielectric layers with different thickness. As a result, we found that the cross-talk reduction effect due to slits is obtained by 3.6-5.3dB, while the cross-talks between signal traces are reduced in inverse proportion to the square of the dielectric-layer thickness and in proportion to the square of the trace interval and, which can quantitatively be explained from an inductive coupling theory.

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

Aoki, Kenji

A read/write head for a magnetic tape includes an elongated chip assembly and a tape running surface formed in the longitudinal direction of the chip assembly. A pair of substantially spaced parallel read/write gap lines for supporting read/write elements extend longitudinally along the tape running surface of the chip assembly. Also, at least one groove is formed on the tape running surface on both sides of each of the read/write gap lines and extends substantially parallel to the read/write gap lines.

Hypersonic Boundary Layer Instability Over a Corner

NASA Technical Reports Server (NTRS)

Balakumar, Ponnampalam; Zhao, Hong-Wu; McClinton, Charles (Technical Monitor)

2001-01-01

A boundary-layer transition study over a compression corner was conducted under a hypersonic flow condition. Due to the discontinuities in boundary layer flow, the full Navier-Stokes equations were solved to simulate the development of disturbance in the boundary layer. A linear stability analysis and PSE method were used to get the initial disturbance for parallel and non-parallel flow respectively. A 2-D code was developed to solve the full Navier-stokes by using WENO(weighted essentially non-oscillating) scheme. The given numerical results show the evolution of the linear disturbance for the most amplified disturbance in supersonic and hypersonic flow over a compression ramp. The nonlinear computations also determined the minimal amplitudes necessary to cause transition at a designed location.

Neoclassical, semi-collisional tearing mode theory in an axisymmetric torus

NASA Astrophysics Data System (ADS)

Connor, J. W.; Hastie, R. J.; Helander, P.

2017-12-01

A set of layer equations for determining the stability of semi-collisional tearing modes in an axisymmetric torus, incorporating neoclassical physics, in the small ion Larmor radius limit, is provided. These can be used as an inner layer module for inclusion in numerical codes that asymptotically match the layer to toroidal calculations of the tearing mode stability index, \\prime $ . They are more complete than in earlier work and comprise equations for the perturbed electron density and temperature, the ion temperature, Ampère's law and the vorticity equation, amounting to a twelvth-order set of radial differential equations. While the toroidal geometry is kept quite general when treating the classical and Pfirsch-Schlüter transport, parallel bootstrap current and semi-collisional physics, it is assumed that the fraction of trapped particles is small for the banana regime contribution. This is to justify the use of a model collision term when acting on the localised (in velocity space) solutions that remain after the Spitzer solutions have been exploited to account for the bulk of the passing distributions. In this respect, unlike standard neoclassical transport theory, the calculation involves the second Spitzer solution connected with a parallel temperature gradient, because this stability problem involves parallel temperature gradients that cannot occur in equilibrium toroidal transport theory. Furthermore, a calculation of the linearised neoclassical radial transport of toroidal momentum for general geometry is required to complete the vorticity equation. The solutions of the resulting set of equations do not match properly to the ideal magnetohydrodynamic (MHD) equations at large distances from the layer, and a further, intermediate layer involving ion corrections to the electrical conductivity and ion parallel thermal transport is invoked to achieve this matching and allow one to correctly calculate the layer \\prime $ .

Differences in α and β polypeptide chains of tubulin resolved by electron microscopy with image reconstruction

PubMed Central

Crepeau, Richard H.; McEwen, Bruce; Edelstein, Stuart J.

1978-01-01

Electron microscopic techniques have been used to reveal two classes of subunits of tubulin in ordered arrays. Presumably the two classes correspond to the α and β polypeptide chains of tubulin that have been distinguished by chemical criteria. The two types of subunits alternate along individual protofilaments in microtubules, microtubule-precursor sheets, and extended zinc-tubulin sheets. The resolution of the two types of polypeptide chains is achieved by improved negative staining methods which produce micrographs with layer lines at 28 Å-1 and 84 Å-1 in optical or computed transforms, in addition to the layer lines at 21 Å-1 and 42 Å-1 described previously [Crepeau, R. H., McEwen, B., Dykes, G. & Edelstein, S. J. (1977) J Mol. Biol. 116, 301-315]. In microtubules or microtubule-precursor sheets, adjacent protofilaments are staggered by about 10 Å, but parallel, in the sense that the α-β vector points in the same direction for all of the protofilaments of the microtubule. However, for the sheets assembled in the presence of zinc, adjacent protofilaments are staggered by about 21 Å and oriented in an antiparallel arrangement with alternate protofilaments related by a 2-fold screw axis. The antiparallel alignment of the protofilaments in the zinc-tubulin sheets accounts for their planarity (no tubular structures are found in the presence of moderate concentrations of zinc), since the intrinsic curvature found with parallel alignment of protofilaments in the absence of zinc would be cancelled by the antiparallel arrangement. Images PMID:283410

Characterization and Simulation of a New Design Parallel-Plate Ionization Chamber for CT Dosimetry at Calibration Laboratories

NASA Astrophysics Data System (ADS)

Perini, Ana P.; Neves, Lucio P.; Maia, Ana F.; Caldas, Linda V. E.

2013-12-01

In this work, a new extended-length parallel-plate ionization chamber was tested in the standard radiation qualities for computed tomography established according to the half-value layers defined at the IEC 61267 standard, at the Calibration Laboratory of the Instituto de Pesquisas Energéticas e Nucleares (IPEN). The experimental characterization was made following the IEC 61674 standard recommendations. The experimental results obtained with the ionization chamber studied in this work were compared to those obtained with a commercial pencil ionization chamber, showing a good agreement. With the use of the PENELOPE Monte Carlo code, simulations were undertaken to evaluate the influence of the cables, insulator, PMMA body, collecting electrode, guard ring, screws, as well as different materials and geometrical arrangements, on the energy deposited on the ionization chamber sensitive volume. The maximum influence observed was 13.3% for the collecting electrode, and regarding the use of different materials and design, the substitutions showed that the original project presented the most suitable configuration. The experimental and simulated results obtained in this work show that this ionization chamber has appropriate characteristics to be used at calibration laboratories, for dosimetry in standard computed tomography and diagnostic radiology quality beams.

Crystal structure of BaMn2(AsO4)2 containing discrete [Mn4O18]28- units.

PubMed

Alcantar, Salvador; Ledbetter, Hollis R; Ranmohotti, Kulugammana G S

2017-12-01

In our attempt to search for mixed alkaline-earth and transition metal arsenates, the title compound, barium dimanganese(II) bis-(arsenate), has been synthesized by employing a high-temperature RbCl flux. The crystal structure of BaMn 2 (AsO 4 ) 2 is made up of MnO 6 octa-hedra and AsO 4 tetra-hedra assembled by sharing corners and edges into infinite slabs with composition [Mn 2 (AsO 4 ) 2 ] 2- that extend parallel to the ab plane. The barium cations reside between parallel slabs maintaining the inter-slab connectivity through coordination to eight oxygen anions. The layered anionic framework comprises weakly inter-acting [Mn 4 O 18 ] 28- tetra-meric units. In each tetra-mer, the manganese(II) cations are in a planar arrangement related by a center of inversion. Within the slabs, the tetra-meric units are separated from each other by 6.614 (2) Å (Mn⋯Mn distances). The title compound has isostructural analogues amongst synthetic Sr M 2 ( X O 4 ) 2 compounds with M = Ni, Co, and X = As, P.

Periodic dielectric structure for production of photonic band gap and devices incorporating the same

DOEpatents

Ho, Kai-Ming; Chan, Che-Ting; Soukoulis, Costas

1994-08-02

A periodic dielectric structure which is capable of producing a photonic band gap and which is capable of practical construction. The periodic structure is formed of a plurality of layers, each layer being formed of a plurality of rods separated by a given spacing. The material of the rods contrasts with the material between the rods to have a refractive index contrast of at least two. The rods in each layer are arranged with their axes parallel and at a given spacing. Adjacent layers are rotated by 90.degree., such that the axes of the rods in any given layer are perpendicular to the axes in its neighbor. Alternating layers (that is, successive layers of rods having their axes parallel such as the first and third layers) are offset such that the rods of one are about at the midpoint between the rods of the other. A four-layer periocity is thus produced, and successive layers are stacked to form a three-dimensional structure which exhibits a photonic band gap. By virtue of forming the device in layers of elongate members, it is found that the device is susceptible of practical construction.

Evolution of Kelvin-Helmholtz instability at Venus in the presence of the parallel magnetic field

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

Lu, H. Y.; Key Laboratory of Planetary Sciences, Chinese Academy of Sciences, Nanjing 210008; Cao, J. B.

2015-06-15

Two-dimensional MHD simulations were performed to study the evolution of the Kelvin-Helmholtz (KH) instability at the Venusian ionopause in response to the strong flow shear in presence of the in-plane magnetic field parallel to the flow direction. The physical behavior of the KH instability as well as the triggering and occurrence conditions for highly rolled-up vortices are characterized through several physical parameters, including Alfvén Mach number on the upper side of the layer, the density ratio, and the ratio of parallel magnetic fields between two sides of the layer. Using these parameters, the simulations show that both the high densitymore » ratio and the parallel magnetic field component across the boundary layer play a role of stabilizing the instability. In the high density ratio case, the amount of total magnetic energy in the final quasi-steady status is much more than that in the initial status, which is clearly different from the case with low density ratio. We particularly investigate the nonlinear development of the case that has a high density ratio and uniform magnetic field. Before the instability saturation, a single magnetic island is formed and evolves into two quasi-steady islands in the non-linear phase. A quasi-steady pattern eventually forms and is embedded within a uniform magnetic field and a broadened boundary layer. The estimation of loss rates of ions from Venus indicates that the stabilizing effect of the parallel magnetic field component on the KH instability becomes strong in the case of high density ratio.« less

Superconducting and Magnetic Properties of Vanadium/iron Superlattices.

NASA Astrophysics Data System (ADS)

Wong, Hong-Kuen

A novel ultrahigh vacuum evaporator was constructed for the preparation of superlattice samples. The thickness control was much better than an atomic plane. With this evaporator we prepared V/Fe superlattice samples on (0001) sapphire substrates with different thicknesses. All samples showed a good bcc(110) structure. Mossbauer experiments showed that the interface mixing extended a distance of about one atomic plane indicating an almost rectangular composition profile. Because of this we were able to prepare samples with layer thickness approaching one atomic plane. Even with ultrathin Fe layers, the samples are ferromagnetic, at least at lower temperatures. Superparamagnetism and spin glass states were not seen. In the absence of an external field, the magnetic moments lie close to the film plane. In addition to this shape anisotropy, there is some uniaxial anisotropy. No magnetic dead layers have been observed. The magnetic moments within the Fe layers vary little with the distance from the interfaces. At the interfaces the Fe moment is reduced and an antiparallel moment is induced on the vanadium atoms. It is observed that ultrathin Fe layers behave in a 2D fashion when isolated by sufficiently thick vanadium layers; however, on thinning the vanadium layers, a magnetic coupling between the Fe layers has been observed. We also studied the superconducting properties of V/Fe sandwiches and superlattices. In both cases, the Fe layer, a strong pair-breaker, suppresses the superconducting transition temperature consistent with the current knowledge of the magnetic proximity effect. For the sandwiches with thin (thick) vanadium layers, the temperature dependence of the upper critical fields is consistent with the simple theory for a 2D (3D) superconductor. For the superlattices, when the vanadium layer is on the order of the BCS coherence length and the Fe layer is only a few atomic planes thick, a 2D-3D crossover has been observed in the temperature dependence of the parallel upper critical field. This implies the coexistence of superconductivity and ferromagnetism. We observe three dimensional behavior for thinner Fe layers ((TURN)1 atomic plane) and two dimensional behavior for thicker Fe layers (greater than 10 atomic planes).

Relation of Parallel Discrete Event Simulation algorithms with physical models

NASA Astrophysics Data System (ADS)

Shchur, L. N.; Shchur, L. V.

2015-09-01

We extend concept of local simulation times in parallel discrete event simulation (PDES) in order to take into account architecture of the current hardware and software in high-performance computing. We shortly review previous research on the mapping of PDES on physical problems, and emphasise how physical results may help to predict parallel algorithms behaviour.

A Connectionist Simulation of Attention and Vector Comparison: The Need for Serial Processing in Parallel Hardware

DTIC Science & Technology

1991-01-01

visual and three-layer connectionist network, in that the input layer of memory processing is serial, and is likely to represent each module is... Selective attention gates visual University Press. processing in the extrastnate cortex. Science, 229:782-784. Treasman, A.M. (1985). Preartentive...AD-A242 225 A CONNECTIONIST SIMULATION OF ATTENTION AND VECTOR COMPARISON: THE NEED FOR SERIAL PROCESSING IN PARALLEL HARDWARE Technical Report AlP

Large-scale trench-perpendicular mantle flow beneath northern Chile

NASA Astrophysics Data System (ADS)

Reiss, M. C.; Rumpker, G.; Woelbern, I.

2017-12-01

We investigate the anisotropic properties of the forearc region of the central Andean margin by analyzing shear-wave splitting from teleseismic and local earthquakes from the Nazca slab. The data stems from the Integrated Plate boundary Observatory Chile (IPOC) located in northern Chile, covering an approximately 120 km wide coastal strip between 17°-25° S with an average station spacing of 60 km. With partly over ten years of data, this data set is uniquely suited to address the long-standing debate about the mantle flow field at the South American margin and in particular whether the flow field beneath the slab is parallel or perpendicular to the trench. Our measurements yield two distinct anisotropic layers. The teleseismic measurements show a change of fast polarizations directions from North to South along the trench ranging from parallel to subparallel to the absolute plate motion and, given the geometry of absolute plate motion and strike of the trench, mostly perpendicular to the trench. Shear-wave splitting from local earthquakes shows fast polarizations roughly aligned trench-parallel but exhibit short-scale variations which are indicative of a relatively shallow source. Comparisons between fast polarization directions and the strike of the local fault systems yield a good agreement. We use forward modelling to test the influence of the upper layer on the teleseismic measurements. We show that the observed variations of teleseismic measurements along the trench are caused by the anisotropy in the upper layer. Accordingly, the mantle layer is best characterized by an anisotropic fast axes parallel to the absolute plate motion which is roughly trench-perpendicular. This anisotropy is likely caused by a combination of crystallographic preferred orientation of the mantle mineral olivine as fossilized anisotropy in the slab and entrained flow beneath the slab. We interpret the upper anisotropic layer to be confined to the crust of the overriding continental plate. This is explained by the shape-preferred orientation of micro-cracks in relation to local fault zones which are oriented parallel the overall strike of the Andean range. Our results do not provide any evidence for a significant contribution of trench-parallel mantle flow beneath the subducting slab to the measurements.

Multileg Heat-Pipe Evaporator

NASA Technical Reports Server (NTRS)

Alario, J. P.; Haslett, R. A.

1986-01-01

Parallel pipes provide high heat flow from small heat exchanger. Six parallel heat pipes extract heat from overlying heat exchanger, forming evaporator. Vapor channel in pipe contains wick that extends into screen tube in liquid channel. Rods in each channel hold wick and screen tube in place. Evaporator compact rather than extended and more compatible with existing heat-exchanger geometries. Prototype six-pipe evaporator only 0.3 m wide and 0.71 m long. With ammonia as working fluid, transports heat to finned condenser at rate of 1,200 W.

Ion manipulation method and device

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

Anderson, Gordon A.; Baker, Erin M.; Smith, Richard D.

2017-11-07

An ion manipulation method and device is disclosed. The device includes a pair of substantially parallel surfaces. An array of inner electrodes is contained within, and extends substantially along the length of, each parallel surface. The device includes a first outer array of electrodes and a second outer array of electrodes. Each outer array of electrodes is positioned on either side of the inner electrodes, and is contained within and extends substantially along the length of each parallel surface. A DC voltage is applied to the first and second outer array of electrodes. A RF voltage, with a superimposed electricmore » field, is applied to the inner electrodes by applying the DC voltages to each electrode. Ions either move between the parallel surfaces within an ion confinement area or along paths in the direction of the electric field, or can be trapped in the ion confinement area.« less

Ion manipulation device

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

Anderson, Gordon A.; Baker, Erin M.; Smith, Richard D.

2018-05-08

An ion manipulation method and device is disclosed. The device includes a pair of substantially parallel surfaces. An array of inner electrodes is contained within, and extends substantially along the length of, each parallel surface. The device includes a first outer array of electrodes and a second outer array of electrodes. Each outer array of electrodes is positioned on either side of the inner electrodes, and is contained within and extends substantially along the length of each parallel surface. A DC voltage is applied to the first and second outer array of electrodes. A RF voltage, with a superimposed electricmore » field, is applied to the inner electrodes by applying the DC voltages to each electrode. Ions either move between the parallel surfaces within an ion confinement area or along paths in the direction of the electric field, or can be trapped in the ion confinement area.« less

A physics-based model of the electrical impedance of ionic polymer metal composites

NASA Astrophysics Data System (ADS)

Cha, Youngsu; Aureli, Matteo; Porfiri, Maurizio

2012-06-01

In this paper, we analyze the chemoelectrical behavior of ionic polymer metal composites (IPMCs) in the small voltage range with a novel hypothesis on the charge dynamics in proximity of the electrodes. In particular, we homogenize the microscopic properties of the interfacial region through a so-called composite layer which extends between the polymer membrane and the metal electrode. This layer accounts for the dissimilar properties of its constituents by describing the charge distribution via two species of charge carriers, that is, electrons and mobile counterions. We model the charge dynamics in the IPMC by adapting the multiphysics formulation based on the Poisson-Nernst-Planck (PNP) framework, which is enriched through an additional term to capture the electron transport in the composite layer. Under the hypothesis of small voltage input, we use the linearized PNP model to derive an equivalent IPMC circuit model with lumped elements. The equivalent model comprises a resistor connected in series with the parallel of a capacitor and a Warburg impedance element. These elements idealize the phenomena of charge build up in the double layer region and the faradaic impedance related to mass transfer, respectively. We validate the equivalent model through measurements on in-house fabricated samples addressing both IPMC step response and impedance, while assessing the influence of repeated plating cycles on the electrical properties of IPMCs. Experimental results are compared with theoretical findings to identify the equivalent circuit parameters. Findings from this study are compared with alternative impedance models proposed in the literature.

Magnetostatic effects on switching in small magnetic tunnel junctions

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

Bapna, Mukund; Piotrowski, Stephan K.; Oberdick, Samuel D.

Perpendicular CoFeB/MgO/CoFeB magnetic tunnel junctions with diameters under 100 nm are investigated by conductive atomic force microscopy. Minor loops of the tunnel magnetoresistance as a function of applied magnetic field reveal the hysteresis of the soft layer and an offset due to the magnetostatic field of the hard layer. Within the hysteretic region, telegraph noise is observed in the tunnel current. Simulations show that in this range, the net magnetic field in the soft layer is spatially inhomogeneous, and that antiparallel to parallel switching tends to start near the edge, while parallel to antiparallel reversal favors nucleation in the interior ofmore » the soft layer. As the diameter of the tunnel junction is decreased, the average magnitude of the magnetostatic field increases, but the spatial inhomogeneity across the soft layer is reduced.« less

Crystal structure of (2,2′-bi­pyridine-κ2 N,N′)bis­(3,5-di-tert-butyl-o-benzo­quinonato-κ2 O,O′)ruthenium(II)

PubMed Central

Ali, Akram; Potaskalov, Vadim A.

2017-01-01

In the title mononuclear complex, [Ru(C14H20O2)2(C10H8N2)], the RuII ion has a distorted octa­hedral coordination environment defined by two N atoms of the chelating 2,2′-bi­pyridine ligand and four O atoms from two 3,5-di-tert-butyl-o-benzo­quinone ligands. In the crystal, the complex mol­ecules are linked by inter­molecular C—H⋯O hydrogen bonds and π–π stacking inter­actions between the 2,2′-bi­pyridine ligands [centroid–centroid distance = 3.538 (3) Å], resulting in a layer structure extending parallel to the ab plane. PMID:28316832

Some observations on rutherfordine

USGS Publications Warehouse

Clark, Joan R.; Christ, C.L.

1956-01-01

The optical properties of rutherfordine, UO2CO3, previously determined on microscopic crystals, have been redetermined on considerably larger crystals; and the relations among the indices of refraction, the morphology, and the crystal structure have been examined. Rutherfordine is orthorhombic, biaxial positive, with α = 1.715, β = 1.730, γ = 1.795, 2V = 53° (calc.); X = b, Y = c (elongation, Z = a. The crystal structure of UO2CO 3 consists of layers of carbonate groups parallel to (010) with linear (O-U-O) ions normal to the layers. The indices β and γ correspond to vibration directions parallel to layers; the unexpectedly large difference in value between β and γ is ascribed to the optical anisotropy of the uranium-oxygen bonding in the layer. Indexed X-ray powder data are given.

Modeling and Characterization of Capacitive Elements With Tissue as Dielectric Material for Wireless Powering of Neural Implants.

PubMed

Erfani, Reza; Marefat, Fatemeh; Sodagar, Amir M; Mohseni, Pedram

2018-05-01

This paper reports on the modeling and characterization of capacitive elements with tissue as the dielectric material, representing the core building block of a capacitive link for wireless power transfer to neural implants. Each capacitive element consists of two parallel plates that are aligned around the tissue layer and incorporate a grounded, guarded, capacitive pad to mitigate the adverse effect of stray capacitances and shield the plates from external interfering electric fields. The plates are also coated with a biocompatible, insulating, coating layer on the inner side of each plate in contact with the tissue. A comprehensive circuit model is presented that accounts for the effect of the coating layers and is validated by measurements of the equivalent capacitance as well as impedance magnitude/phase of the parallel plates over a wide frequency range of 1 kHz-10 MHz. Using insulating coating layers of Parylene-C at a thickness of and Parylene-N at a thickness of deposited on two sets of parallel plates with different sizes and shapes of the guarded pad, our modeling and characterization results accurately capture the effect of the thickness and electrical properties of the coating layers on the behavior of the capacitive elements over frequency and with different tissues.

ORCA Project: Research on high-performance parallel computer programming environments. Final report, 1 Apr-31 Mar 90

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

Snyder, L.; Notkin, D.; Adams, L.

1990-03-31

This task relates to research on programming massively parallel computers. Previous work on the Ensamble concept of programming was extended and investigation into nonshared memory models of parallel computation was undertaken. Previous work on the Ensamble concept defined a set of programming abstractions and was used to organize the programming task into three distinct levels; Composition of machine instruction, composition of processes, and composition of phases. It was applied to shared memory models of computations. During the present research period, these concepts were extended to nonshared memory models. During the present research period, one Ph D. thesis was completed, onemore » book chapter, and six conference proceedings were published.« less

Distributed intelligence for supervisory control

NASA Technical Reports Server (NTRS)

Wolfe, W. J.; Raney, S. D.

1987-01-01

Supervisory control systems must deal with various types of intelligence distributed throughout the layers of control. Typical layers are real-time servo control, off-line planning and reasoning subsystems and finally, the human operator. Design methodologies must account for the fact that the majority of the intelligence will reside with the human operator. Hierarchical decompositions and feedback loops as conceptual building blocks that provide a common ground for man-machine interaction are discussed. Examples of types of parallelism and parallel implementation on several classes of computer architecture are also discussed.

Parallel heater system for subsurface formations

DOEpatents

Harris, Christopher Kelvin [Houston, TX; Karanikas, John Michael [Houston, TX; Nguyen, Scott Vinh [Houston, TX

2011-10-25

A heating system for a subsurface formation is disclosed. The system includes a plurality of substantially horizontally oriented or inclined heater sections located in a hydrocarbon containing layer in the formation. At least a portion of two of the heater sections are substantially parallel to each other. The ends of at least two of the heater sections in the layer are electrically coupled to a substantially horizontal, or inclined, electrical conductor oriented substantially perpendicular to the ends of the at least two heater sections.

New Hybridized Surface Wave Approach for Geotechnical Modeling of Shear Wave Velocity at Strong Motion Recording Stations

NASA Astrophysics Data System (ADS)

Kayen, R.; Carkin, B.; Minasian, D.

2006-12-01

Strong motion recording (SMR) networks often have little or no shear wave velocity measurements at stations where characterization of site amplification and site period effects is needed. Using the active Spectral Analysis of Surface Waves (SASW) method, and passive H/V microtremor method we have investigated nearly two hundred SMR sites in California, Alaska, Japan, Australia, China and Taiwan. We are conducting these studies, in part, to develop a new hybridized method of site characterization that utilizes a parallel array of harmonic-wave sources for active-source SASW, and a single long period seismometer for passive-source microtremor measurement. Surface wave methods excel in their ability to non-invasively and rapidly characterize the variation of ground stiffness properties with depth below the surface. These methods are lightweight, inexpensive to deploy, and time-efficient. They have been shown to produce accurate and deep soil stiffness profiles. By placing and wiring shakers in a large parallel circuit, either side-by-side on the ground or in a trailer-mounted array, a strong in-phase harmonic wave can be produced. The effect of arraying many sources in parallel is to increase the amplitude of waves received at far-away spaced seismometers at low frequencies so as to extend the longest wavelengths of the captured dispersion curve. The USGS system for profiling uses this concept by arraying between two and eight electro-mechanical harmonic-wave shakers. With large parallel arrays of vibrators, a dynamic force in excess of 1000 lb can be produced to vibrate the ground and produce surface waves. We adjust the harmonic wave through a swept-sine procedure to profile surface wave dispersion down to a frequency of 1 Hz and out to surface wave-wavelengths of 200-1000 meters, depending on the site stiffness. The parallel-array SASW procedure is augmented using H/V microtremor data collected with the active source turned off. Passive array microtremor data reveal the natural and resonance characteristics of the ground by capturing persistent natural vibrations. These microtremors are the result of the interaction of surface waves arriving from distant sources and the stiffness structure of the site under investigation. As such, these resonance effects are effective in constraining the layer thicknesses of the SASW shear wave velocity structure and aid in determining the depth of the deepest layer. Together, the hybridized SASW and H/V procedure provides a complete data set for modeling the geotechnical aspects of ground amplification of earthquake motions. Data from these investigations are available at http://walrus.wr.usgs.gov/geotech.

Development of Cranial Bone Surrogate Structures Using Stereolithographic Additive Manufacturing

DTIC Science & Technology

2017-09-29

shown in Fig. 5. With each cycle, a blade is passed across the platform to create a uniform layer of resin. The resin layer is exposed to a UV laser...due to the direction in which the layers are deposited. In both cases, the sequential layers run parallel to the loading direction of the tensile

Simulation of ground-water flow to assess geohydrologic factors and their effect on source-water areas for bedrock wells in Connecticut

USGS Publications Warehouse

Starn, J. Jeffrey; Stone, Janet Radway

2005-01-01

Generic ground-water-flow simulation models show that geohydrologic factors?fracture types, fracture geometry, and surficial materials?affect the size, shape, and location of source-water areas for bedrock wells. In this study, conducted by the U.S. Geological Survey in cooperation with the Connecticut Department of Public Health, ground-water flow was simulated to bedrock wells in three settings?on hilltops and hillsides with no surficial aquifer, in a narrow valley with a surficial aquifer, and in a broad valley with a surficial aquifer?to show how different combinations of geohydrologic factors in different topographic settings affect the dimensions and locations of source-water areas in Connecticut. Three principal types of fractures are present in bedrock in Connecticut?(1) Layer-parallel fractures, which developed as partings along bedding in sedimentary rock and compositional layering or foliation in metamorphic rock (dips of these fractures can be gentle or steep); (2) unroofing joints, which developed as strain-release fractures parallel to the land surface as overlying rock was removed by erosion through geologic time; and (3) cross fractures and joints, which developed as a result of tectonically generated stresses that produced typically near-vertical or steeply dipping fractures. Fracture geometry is defined primarily by the presence or absence of layering in the rock unit, and, if layered, by the angle of dip in the layering. Where layered rocks dip steeply, layer-parallel fracturing generally is dominant; unroofing joints also are typically well developed. Where layered rocks dip gently, layer-parallel fracturing also is dominant, and connections among these fractures are provided only by the cross fractures. In gently dipping rocks, unroofing joints generally do not form as a separate fracture set; instead, strain release from unroofing has occurred along gently dipping layer-parallel fractures, enhancing their aperture. In nonlayered and variably layered rocks, layer-parallel fracturing is absent or poorly developed; fracturing is dominated by well-developed subhorizontal unroofing joints and steeply dipping, tectonically generated fractures and (or) cooling joints. Cross fractures (or cooling joints) in nonlayered and variably layered rocks have more random orientations than in layered rocks. Overall, nonlayered or variably layered rocks do not have a strongly developed fracture direction. Generic ground-water-flow simulation models showed that fracture geometry and other geohydrologic factors affect the dimensions and locations of source-water areas for bedrock wells. In general, source-water areas to wells reflect the direction of ground-water flow, which mimics the land-surface topography. Source-water areas to wells in a hilltop setting were not affected greatly by simulated fracture zones, except for an extensive vertical fracture zone. Source-water areas to wells in a hillside setting were not affected greatly by simulated fracture zones, except for the combination of a subhorizontal fracture zone and low bedrock vertical hydraulic conductivity, as might be the case where an extensive subhorizontal fracture zone is not connected or is poorly connected to the surface through vertical fractures. Source-water areas to wells in a narrow valley setting reflect complex ground-water-flow paths. The typical flow path originates in the uplands and passes through either till or bedrock into the surficial aquifer, although only a small area of the surficial aquifer actually contributes water to the well. Source-water areas in uplands can include substantial areas on both sides of a river. Source-water areas for wells in this setting are affected mainly by the rate of ground-water recharge and by the degree of anisotropy. Source-water areas to wells in a broad valley setting (bedrock with a low angle of dip) are affected greatly by fracture properties. The effect of a given fracture is to channel the

Early Cretaceous Ductile Deformation of Marbles from the Western Hills of Beijing, North China Craton

NASA Astrophysics Data System (ADS)

Feng, H.; Liu, J.

2017-12-01

During the Early Cretaceous tectonic lithosphere extension, the pre-mesozoic rocks from the Western Hills in the central part of the North China Craton suffered from weak metamorphism but intense shear deformation. The prominent features of the deformation structures are the coexisting layer-parallel shear zones and intrafolia folds, and the along-strike thickness variations of the marble layers from the highly sheared Mesoproterozoic Jing'eryu Formation. Platy marbles are well-developed in the thinner layers, while intrafolia folds are often observed in the thicker layers. Most folds are tight recumbent folds and their axial planes are parallel to the foliations and layerings of the marbles. The folds are A-type folds with hinges being always paralleling to the stretching lineations consistently oriented at 130°-310° directions throughout the entire area. SPO and microstructural analyses of the sheared marbles suggest that the thicker layers suffered from deformations homogeneously, while strain localization can be distinguished in the thinner layers. Calcite twin morphology and CPO analysis indicate that the deformation of marbles from both thinner and thicker layers happened at temperatures of 300 to 500°C. The above analysis suggests that marbles in the thicker layers experienced a progressive sequence of thermodynamic events: 1) regional metamorphism, 2) early ductile deformation dominated by relatively higher temperature conditions, during which all the mineral particles elongated and oriented limitedly and the calcite grains are deformed mainly by mechanical twinning, and 3) late superimposition of relatively lower temperature deformation and recrystallization, which superposed the early deformation, and made the calcites finely granulated, elongated and oriented by dynamical recrystallization along with other grains. Marbles from the thinner layers, however, experienced a similar, but different sequence of thermo-dynamic events, i.e. regional metamorphism, early ductile deformation and weak superimposition by subsequent deformation, which caused the development of the strain localization. It is also shown that the intensity of progressive superimposition deformation contributed to the thinning and thickening of the marble layers.

3-D readout-electronics packaging for high-bandwidth massively paralleled imager

DOEpatents

Kwiatkowski, Kris; Lyke, James

2007-12-18

Dense, massively parallel signal processing electronics are co-packaged behind associated sensor pixels. Microchips containing a linear or bilinear arrangement of photo-sensors, together with associated complex electronics, are integrated into a simple 3-D structure (a "mirror cube"). An array of photo-sensitive cells are disposed on a stacked CMOS chip's surface at a 45.degree. angle from light reflecting mirror surfaces formed on a neighboring CMOS chip surface. Image processing electronics are held within the stacked CMOS chip layers. Electrical connections couple each of said stacked CMOS chip layers and a distribution grid, the connections for distributing power and signals to components associated with each stacked CSMO chip layer.

Interlayer tunneling in double-layer quantum hall pseudoferromagnets.

PubMed

Balents, L; Radzihovsky, L

2001-02-26

We show that the interlayer tunneling I-V in double-layer quantum Hall states displays a rich behavior which depends on the relative magnitude of sample size, voltage length scale, current screening, disorder, and thermal lengths. For weak tunneling, we predict a negative differential conductance of a power-law shape crossing over to a sharp zero-bias peak. An in-plane magnetic field splits this zero-bias peak, leading instead to a "derivative" feature at V(B)(B(parallel)) = 2 pi Planck's over 2 pi upsilon B(parallel)d/e phi(0), which gives a direct measurement of the dispersion of the Goldstone mode corresponding to the spontaneous symmetry breaking of the double-layer Hall state.

Epithelial innervation of human cornea: a three-dimensional study using confocal laser scanning fluorescence microscopy.

PubMed

Guthoff, Rudolf F; Wienss, Holger; Hahnel, Christian; Wree, Andreas

2005-07-01

Evaluation of a new method to visualize distribution and morphology of human corneal nerves (Adelta- and C-fibers) by means of fluorescence staining, confocal laser scanning microscopy, and 3-dimensional (3D) reconstruction. Trephinates of corneas with a diagnosis of Fuchs corneal dystrophy were sliced into layers of 200 microm thickness using a Draeger microkeratome (Storz, Germany). The anterior lamella was stained with the Life/Dead-Kit (Molecular Probes Inc.), examined by the confocal laser scanning microscope "Odyssey XL," step size between 0.5 and 1 microm, and optical sections were digitally 3D-reconstructed. Immediate staining of explanted corneas by the Life/Dead-Kit gave a complete picture of the nerves in the central human cornea. Thin nerves running parallel to the Bowman layer in the subepithelial plexus perforate the Bowman layer orthogonally through tube-like structures. Passing the Bowman layer, Adelta- and C-fibers can be clearly distinguished by fiber diameter, and, while running in the basal epithelial plexus, by their spatial arrangement. Adelta-fibers run straight and parallel to the Bowman layer underneath the basal cell layer. C-fibers, after a short run parallel to the Bowman layer, send off multiple branches penetrating epithelial cell layers orthogonally, ending blindly in invaginations of the superficial cells. In contrast to C-fibers, Adelta-fibers show characteristic bulbous formations when kinking into the basal epithelial plexus. Ex-vivo fluorescence staining of the cornea and 3D reconstructions of confocal scans provide a fast and easily reproducible tool to visualize nerves of the anterior living cornea at high resolution. This may help to clarify gross variations of nerve fiber patterns under various clinical and experimental conditions.

The effects of a uniform axial magnetic field on the global stability of the rotating-disk boundary-layer

NASA Astrophysics Data System (ADS)

Davies, Christopher; Thomas, Christian

2006-11-01

Following on from the earlier discovery by Lingwood (1995) that the rotating-disk boundary-layer is absolutely unstable, Jasmine & Gajjar (2005) have shown that the application of a uniform axial magnetic field can raise the critical Reynolds number for the onset of absolute instability. As with Lingwood's analysis, a parallel-flow' type of approximation is needed in order to derive this locally-based stability result. The approximation amounts to a freezing out' of the underlying radial variation of the mean flow. Numerical simulations have been conducted to investigate the behaviour of linearized disturbances in the genuine rotating disk boundary layer, where the radial dependence of the mean flow is fully accounted for. This extends the work of Davies & Carpenter (2003), who studied the more usual rotating-disk problem, in the absence of any magnetic field. The simulation results suggest that globally unstable behaviour can be promoted when a uniform axial magnetic field is applied. Impulsively excited disturbances were found to display an increasingly rapid growth at the radial position of the impulse, albeit without any selection of a dominant frequency, as would be more usual for an unstable global mode. This is very similar to the behaviour to that was observed in a recent investigation by Davies & Thomas (2005) of the effects of mass transfer, where suction was also found to promote global instability.

Wavelength-selective ultraviolet (Mg,Zn)O photodiodes: Tuning of parallel composition gradients with oxygen pressure

NASA Astrophysics Data System (ADS)

Zhang, Zhipeng; von Wenckstern, Holger; Lenzner, Jörg; Grundmann, Marius

2016-06-01

We report on ultraviolet photodiodes with integrated optical filter based on the wurtzite (Mg,Zn)O thin films. Tuning of the bandgap of filter and active layers was realized by employing a continuous composition spread approach relying on the ablation of a single segmented target in pulsed-laser deposition. Filter and active layers of the device were deposited on opposite sides of a sapphire substrate with nearly parallel compositional gradients. Ensure that for each sample position the bandgap of the filter layer blocking the high energy radiation is higher than that of the active layer. Different oxygen pressures during the two depositions runs. The absorption edge is tuned over 360 meV and the spectral bandwidth of photodiodes is typically 100 meV and as low as 50 meV.

Seismic reflections identify finite differences in gas hydrate resources

USGS Publications Warehouse

Dillon, William P.; Max, M.

1999-01-01

Gas hydrate is a gas-bearing, ice-like crystalline solid. The substance's build ing blocks consist of a gas molecule (generally methane) sur-rounded by a cage of water molecules. The total amount of methane in hydrate in the world is immense - the most recent speculative estimate centers on values of 21x1015 cu meters. Thus, it may represent a future energy resource. This estimate was presented by Keith Kvenvolden at the International Symposium on Methane Hydrates, Resources in the Near Future, sponsor ed by Japanese National Oil Company (Tokyo, October, 1998).But, as with any natural resource, there is a need to find naturally occurring concentrations in order to effectively extract gas. We need to answer four basic questions:Do methane hydrate concentrations suitable for methane extraction exist?How can we recognize these concentrations?Where are concentrations located?What processes control methane hydrate concentrations?Gas hydrate occurs naturally at the pressure/ temperature/chemical conditions that are present within ocean floor sediments at water depths greater than about 500 meters. The gas hydrate stability zone (GHSZ) extends from the sea bottom downward to a depth where the natural increase in temperature causes the hydrate to melt (dissociate), even though the downward pressure increase is working to increase gas hydrate stability.Thus, the base of the GHSZ tends to parallel the seafloor at any given water depth (pressure), because the sub-seafloor isotherms (depths of constant temperature) generally parallel the seafloor. The layer at which gas hydrate is stable commonly extends from the sea floor to several hundred meters below it. The gas in most gas hydrates is methane, generated by bacteria in the sediments. In some cases, it can be higher carbon-number, thermogenic hydrocarbon gases that rise from greater depths.

Influence of a forest canopy on velocity and temperature profiles under synoptic conditions

NASA Astrophysics Data System (ADS)

Pattantyus, A.; Hocut, C. M.; Wang, Y.; Creegan, E.; Krishnamurthy, R.; Otarola-Bust, S.; Leo, L. S.; Fernando, H. J. S.

2017-12-01

Numerous field campaigns have found the importance of surface conditions on boundary layer evolution. Specifically, soil properties were found to control surface fluxes of heat, moisture, and momentum that significantly modulated the atmospheric boundary layer (ABL) over flat and sparsely vegetated surfaces. There have been increasing numbers of studies related to canopy impacts on the boundary layer, such as CHATS, however few canopy studies over complex terrain have been performed with limited instrumentation. The recent Perdigão campaign greatly augmented the previous datasets available by instrumenting a unique, parallel ridge mountain in Perdigão, Portugal in unprecedented spatial and temporal resolution using traditional mast mounted sensors, instrumented aerial platforms, and remote sensing instrumentation. To aid the canopy studies, the Army Research Laboratory deployed sonic anemometers within the canopy transecting the ridges perpendicularly and placed five additional heavily instrumented meteorological masts on the northeast facing slope to investigate detailed slope flows. At each of these towers, there was an average of six levels of temperature, relative humidity, and wind sensors located above & below the canopy height which allowed a detailed study of the sub-canopy layer. In addition to the towers, two scanning Doppler LiDARs were oriented such that they performed synchronized dual Doppler virtual tower scans, extending from the canopy interface to several hundred meters above. Synoptically forced periods were analyzed to examine: the ABL structure of temperature, moisture, wind, and turbulent kinetic energy. Of particular interest are the shear layer at the canopy interface, recirculation events, as well as ejection and sweep events within the canopy and how these modify surface fluxes along the slopes.

Memory access in shared virtual memory

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

Berrendorf, R.

1992-01-01

Shared virtual memory (SVM) is a virtual memory layer with a single address space on top of a distributed real memory on parallel computers. We examine the behavior and performance of SVM running a parallel program with medium-grained, loop-level parallelism on top of it. A simulator for the underlying parallel architecture can be used to examine the behavior of SVM more deeply. The influence of several parameters, such as the number of processors, page size, cold or warm start, and restricted page replication, is studied.

Memory access in shared virtual memory

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

Berrendorf, R.

1992-09-01

Shared virtual memory (SVM) is a virtual memory layer with a single address space on top of a distributed real memory on parallel computers. We examine the behavior and performance of SVM running a parallel program with medium-grained, loop-level parallelism on top of it. A simulator for the underlying parallel architecture can be used to examine the behavior of SVM more deeply. The influence of several parameters, such as the number of processors, page size, cold or warm start, and restricted page replication, is studied.

Parallel adaptive discontinuous Galerkin approximation for thin layer avalanche modeling

NASA Astrophysics Data System (ADS)

Patra, A. K.; Nichita, C. C.; Bauer, A. C.; Pitman, E. B.; Bursik, M.; Sheridan, M. F.

2006-08-01

This paper describes the development of highly accurate adaptive discontinuous Galerkin schemes for the solution of the equations arising from a thin layer type model of debris flows. Such flows have wide applicability in the analysis of avalanches induced by many natural calamities, e.g. volcanoes, earthquakes, etc. These schemes are coupled with special parallel solution methodologies to produce a simulation tool capable of very high-order numerical accuracy. The methodology successfully replicates cold rock avalanches at Mount Rainier, Washington and hot volcanic particulate flows at Colima Volcano, Mexico.

Crystal structure of dipotassium N-carbodi­thio­ato-l-prolinate trihydrate

PubMed Central

2017-01-01

The mol­ecular and crystal structure of the l-proline-derived di­thio­carbamate–carboxyl­ate compound poly[tri-μ-aqua-(μ-2-carboxyl­atopyrrolidine-1-carbodi­thio­ato)dipotassium], [K2(C6H7NO2S2)(H2O)3]n or K2(SSC–NC4H7–COO)·3H2O, has been determined. The di­thio­carbamate moiety displays a unique coordination mode, comprising a ‘side-on’ π-coordinated K+ cation besides a commonly σ-chelated K+ cation. By bridging coordination of the CSS group, COO group and water mol­ecules, the K+ cations are linked into a two-dimensional coordination polymer extending parallel to the ab plane. These layers are again inter­connected by O—H⋯S hydrogen bonds. PMID:28932478

Redetermination of 2-methyl-4-nitro­pyridine N-oxide

PubMed Central

Peukert, Max; Seichter, Wilhelm; Weber, Edwin

2014-01-01

An improved crystal structure of the title compound, C6H6N2O3, is reported. The structure, previously solved [Li et al. (1987 ▶). Jiegou Huaxue (Chin. J. Struct. Chem.), 6, 20–24] in the ortho­rhom­bic space group Pca21 and refined to R = 0.067, has been solved in the ortho­rhom­bic space group Pbcm with data of enhanced quality, giving an improved structure (R = 0.0485). The mol­ecule adopts a planar conformation with all atoms lying on a mirror plane. The crystal structure is composed of mol­ecular sheets extending parallel to the ab plane and connected via C—H⋯O contacts involving ring H atoms and O atoms of the N-oxide and nitro groups, while van der Waals forces consolidate the stacking of the layers. PMID:24826136

Wake Vortex Transport in Proximity to the Ground

NASA Technical Reports Server (NTRS)

Hamilton, David W.; Proctor, Fred H.

2000-01-01

A sensitivity study for aircraft wake vortex transport has been conducted using a validated large eddy simulation (LES) model. The study assumes neutrally stratified and nonturbulent environments and includes the consequences of the ground. The numerical results show that the nondimensional lateral transport is primarily influenced by the magnitude of the ambient crosswind and is insensitive to aircraft type. In most of the simulations, the ground effect extends the lateral position of the downwind vortex about one initial vortex spacing (b(sub o)) in the downstream direction. Further extension by as much as one b(sub o) occurs when the downwind vortex remains 'in ground effect' (IGE) for relatively long periods of time. Results also show that a layer-averaged ambient wind velocity can be used to bound the time for lateral transport of wake vortices to insure safe operations on a parallel runway.

Parallel Tracks as Quasi-steady States for the Magnetic Boundary Layers in Neutron-star Low-mass X-Ray Binaries

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

Erkut, M. Hakan; Çatmabacak, Onur, E-mail: mherkut@gmail.com

The neutron stars in low-mass X-ray binaries (LMXBs) are usually thought to be weakly magnetized objects accreting matter from their low-mass companions in the form of a disk. Albeit weak compared to those in young neutron-star systems, the neutron-star magnetospheres in LMXBs can play an important role in determining the correlations between spectral and temporal properties. Parallel tracks appearing in the kilohertz (kHz) quasi-periodic oscillation (QPO) frequency versus X-ray flux plane can be used as a tool to study the magnetosphere–disk interaction in neutron-star LMXBs. For dynamically important weak fields, the formation of a non-Keplerian magnetic boundary layer at themore » innermost disk truncated near the surface of the neutron star is highly likely. Such a boundary region may harbor oscillatory modes of frequencies in the kHz range. We generate parallel tracks using the boundary region model of kHz QPOs. We also present the direct application of our model to the reproduction of the observed parallel tracks of individual sources such as 4U 1608–52, 4U 1636–53, and Aql X-1. We reveal how the radial width of the boundary layer must vary in the long-term flux evolution of each source to regenerate the parallel tracks. The run of the radial width looks similar for different sources and can be fitted by a generic model function describing the average steady behavior of the boundary region over the long term. The parallel tracks then correspond to the possible quasi-steady states the source can occupy around the average trend.« less

Parallel Tracks as Quasi-steady States for the Magnetic Boundary Layers in Neutron-star Low-mass X-Ray Binaries

NASA Astrophysics Data System (ADS)

Erkut, M. Hakan; Çatmabacak, Onur

2017-11-01

The neutron stars in low-mass X-ray binaries (LMXBs) are usually thought to be weakly magnetized objects accreting matter from their low-mass companions in the form of a disk. Albeit weak compared to those in young neutron-star systems, the neutron-star magnetospheres in LMXBs can play an important role in determining the correlations between spectral and temporal properties. Parallel tracks appearing in the kilohertz (kHz) quasi-periodic oscillation (QPO) frequency versus X-ray flux plane can be used as a tool to study the magnetosphere-disk interaction in neutron-star LMXBs. For dynamically important weak fields, the formation of a non-Keplerian magnetic boundary layer at the innermost disk truncated near the surface of the neutron star is highly likely. Such a boundary region may harbor oscillatory modes of frequencies in the kHz range. We generate parallel tracks using the boundary region model of kHz QPOs. We also present the direct application of our model to the reproduction of the observed parallel tracks of individual sources such as 4U 1608-52, 4U 1636-53, and Aql X-1. We reveal how the radial width of the boundary layer must vary in the long-term flux evolution of each source to regenerate the parallel tracks. The run of the radial width looks similar for different sources and can be fitted by a generic model function describing the average steady behavior of the boundary region over the long term. The parallel tracks then correspond to the possible quasi-steady states the source can occupy around the average trend.

Bi-directional series-parallel elastic actuator and overlap of the actuation layers.

PubMed

Furnémont, Raphaël; Mathijssen, Glenn; Verstraten, Tom; Lefeber, Dirk; Vanderborght, Bram

2016-01-27

Several robotics applications require high torque-to-weight ratio and energy efficient actuators. Progress in that direction was made by introducing compliant elements into the actuation. A large variety of actuators were developed such as series elastic actuators (SEAs), variable stiffness actuators and parallel elastic actuators (PEAs). SEAs can reduce the peak power while PEAs can reduce the torque requirement on the motor. Nonetheless, these actuators still cannot meet performances close to humans. To combine both advantages, the series parallel elastic actuator (SPEA) was developed. The principle is inspired from biological muscles. Muscles are composed of motor units, placed in parallel, which are variably recruited as the required effort increases. This biological principle is exploited in the SPEA, where springs (layers), placed in parallel, can be recruited one by one. This recruitment is performed by an intermittent mechanism. This paper presents the development of a SPEA using the MACCEPA principle with a self-closing mechanism. This actuator can deliver a bi-directional output torque, variable stiffness and reduced friction. The load on the motor can also be reduced, leading to a lower power consumption. The variable recruitment of the parallel springs can also be tuned in order to further decrease the consumption of the actuator for a given task. First, an explanation of the concept and a brief description of the prior work done will be given. Next, the design and the model of one of the layers will be presented. The working principle of the full actuator will then be given. At the end of this paper, experiments showing the electric consumption of the actuator will display the advantage of the SPEA over an equivalent stiff actuator.

Document Image Parsing and Understanding using Neuromorphic Architecture

DTIC Science & Technology

2015-03-01

processing speed at different layers. In the pattern matching layer, the computing power of multicore processors is explored to reduce the processing...developed to reduce the processing speed at different layers. In the pattern matching layer, the computing power of multicore processors is explored... cortex where the complex data is reduced to abstract representations. The abstract representation is compared to stored patterns in massively parallel

Photocapacitive image converter

NASA Technical Reports Server (NTRS)

Miller, W. E.; Sher, A.; Tsuo, Y. H. (Inventor)

1982-01-01

An apparatus for converting a radiant energy image into corresponding electrical signals including an image converter is described. The image converter includes a substrate of semiconductor material, an insulating layer on the front surface of the substrate, and an electrical contact on the back surface of the substrate. A first series of parallel transparent conductive stripes is on the insulating layer with a processing circuit connected to each of the conductive stripes for detecting the modulated voltages generated thereon. In a first embodiment of the invention, a modulated light stripe perpendicular to the conductive stripes scans the image converter. In a second embodiment a second insulating layer is deposited over the conductive stripes and a second series of parallel transparent conductive stripes perpendicular to the first series is on the second insulating layer. A different frequency current signal is applied to each of the second series of conductive stripes and a modulated image is applied to the image converter.

On the Salt Water Intrusion into the Durusu Lake, Istanbul: A Joint Central Loop TEM And Multi-Electrode ERT Field Survey

NASA Astrophysics Data System (ADS)

Ardali, Ayça Sultan; Tezkan, Bülent; Gürer, Aysan

2018-02-01

Durusu Lake is the biggest and most important freshwater source supplying drinking water to the European side of Istanbul. In this study, electrical resistivity tomography (ERT) and transient electromagnetic (TEM) measurements were applied to detect a possible salt water intrusion into the lake and to delineate the subsurface structure in the north of Durusu Lake. The ERT and TEM measurements were carried out along six parallel profiles extending from the sea coast to the lake shore on the dune barrier. TEM data were interpreted using different 1-D inversion methods such as Occam, Marquardt, and laterally constrained inversion (LCI). ERT data were interpreted using 2-D inversion techniques. The inversion results of ERT and TEM data were shown as resistivity depth sections including topography. The sand layer spreading over the basin has a resistivity of 150-400 Ωm with a thickness of 5-10 m. The sandy layer with clay, silt, and gravel has a resistivity of 15-100 Ωm and a thickness of 10-40 m followed by a clay layer of a resistivity below 10 Ωm. When the inversion of these data is interpreted along with the hydrogeology of the area, it is concluded that the salt water intrusion along the dune barrier is not common and occurs at a particular area where the distance between lake and sea is very close. Using information from boreholes around the lake, it was verified that the common conductive region at depths of 30 m or more consists of clay layers and clay lenses.

Nonhyperbolic reflection moveout for horizontal transverse isotropy

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

Al-Dajani, A.F.; Tsvankin, I.

1998-09-01

The transversely isotropic model with a horizontal axis of symmetry (HTI) has been used extensively in studies of shear-wave splitting to describe fractured formations with a single system of parallel vertical penny-shaped cracks. Here, the authors present an analytic description of long-spread reflection moveout in horizontally layered HTI media with arbitrary strength of anisotropy. To account for nonhyperbolic moveout, the authors have derived an exact expression for the azimuthally dependent quartic term of the Taylor series traveltime expansion valid for any pure mode in an HTI layer. The quartic moveout coefficient and the NMO velocity are then substituted into themore » nonhyperbolic moveout equation of Tsvankin and Thomsen, originally designed for vertical transverse isotropy (VTI). In multilayered HTI media, the NMO velocity and the quartic moveout coefficient reflect the influence of layering as well as azimuthal anisotropy. The authors show that the conventional Dix equation for NMO velocity remains entirely valid for any azimuth in HTI media if the group-velocity vectors (rays) for data in a common-midpoint (CMP) gather do not deviate from the vertical incidence plane. Although this condition is not exactly satisfied in the presence of azimuthal velocity variations, rms averaging of the interval NMO velocities represents a good approximation for models with moderate azimuthal anisotropy. Furthermore, the quartic moveout coefficient for multilayered HTI media can also be calculated with acceptable accuracy using the known averaging equations for vertical transverse isotropy. This allows one to extend the nonhyperbolic moveout equation to horizontally stratified media composed of any combination of isotropic, VTI, and HTI layers.« less

Parallel Education and Defining the Fourth Sector.

ERIC Educational Resources Information Center

Chessell, Diana

1996-01-01

Parallel to the primary, secondary, postsecondary, and adult/community education sectors is education not associated with formal programs--learning in arts and cultural sites. The emergence of cultural and educational tourism is an opportunity for adult/community education to define itself by extending lifelong learning opportunities into parallel…

Thermocooling of GMR Sensors

NASA Technical Reports Server (NTRS)

Davis, Despina (Inventor); Mannam, Raja Sekharam (Inventor); Bellamkonda, Ramya (Inventor)

2013-01-01

A thermoelectrically cooled GMR sensor having a first thermoelectric layer with an array of nanowires, wherein the nanowires include a diameter of about 1 nanometer to about 1000 nanometers. A plurality of alternating layers of magnetic and nonmagnetic material are positioned over and extend the nanowires to form a GMR assembly. A second thermoelectric layer is positioned over the GMR assembly and extends the nanowires, such that the nanowires have a length of between about 100 nanometers and about 500 microns. Conductors are placed in contact with the first and second thermoelectric layers for connecting the thermoelectric layers to a voltage source.

Hairpin vortices in turbulent boundary layers

NASA Astrophysics Data System (ADS)

Eitel-Amor, G.; Örlü, R.; Schlatter, P.; Flores, O.

2015-02-01

The present work presents a number of parallel and spatially developing simulations of boundary layers to address the question of whether hairpin vortices are a dominant feature of near-wall turbulence, and which role they play during transition. In the first part, the parent-offspring regeneration mechanism is investigated in parallel (temporal) simulations of a single hairpin vortex introduced in a mean shear flow corresponding to either turbulent channels or boundary layers (Reτ ≲ 590). The effect of a turbulent background superimposed on the mean flow is considered by using an eddy viscosity computed from resolved simulations. Tracking the vortical structure downstream, it is found that secondary hairpins are only created shortly after initialization, with all rotational structures decaying for later times. For hairpins in a clean (laminar) environment, the decay is relatively slow, while hairpins in weak turbulent environments (10% of νt) dissipate after a couple of eddy turnover times. In the second part, the role of hairpin vortices in laminar-turbulent transition is studied using simulations of spatial boundary layers tripped by hairpin vortices. These vortices are generated by means of specific volumetric forces representing an ejection event, creating a synthetic turbulent boundary layer initially dominated by hairpin-like vortices. These hairpins are advected towards the wake region of the boundary layer, while a sinusoidal instability of the streaks near the wall results in rapid development of a turbulent boundary layer. For Reθ > 400, the boundary layer is fully developed, with no evidence of hairpin vortices reaching into the wall region. The results from both the parallel and spatial simulations strongly suggest that the regeneration process is rather short-lived and may not sustain once a turbulent background is developed. From the transitional flow simulations, it is conjectured that the forest of hairpins reported in former direct numerical simulation studies is reminiscent of the transitional boundary layer and may not be connected to some aspects of the dynamics of the fully developed wall-bounded turbulence.

Valles Marineris as a Cryokarstic Structure Formed by a Giant Dyke System: Support From New Analogue Experiments

NASA Astrophysics Data System (ADS)

Ozeren, M. S.; Sengor, A. M. C.; Acar, D.; Ülgen, S. C.; Onsel, I. E.

2014-12-01

Valles Marineris is the most significant near-linear depression on Mars. It is some 4000 km long, up to about 200 km wide and some 7 km deep. Although its margins look parallel at first sight, the entire structure has a long spindle shape with significant enlargement in its middle (Melas Chasma) caused by cuspate slope retreat mechanisms. Farther to its north is Hebes Chasma which is an entirely closed depression with a more pronounced spindle shape. Tithonium Chasma is a parallel, but much narrower depression to its northeast. All these chasmae have axes parallel with one another and such structures occur nowhere else on Mars. A scabland surface exists to the east of the Valles Marineris and the causative water mass seems to have issued from it. The great resemblance of these chasmae on mars to poljes in the karstic regions on earth have led us to assume that they owed their existence to dissolution of rock layers underlying them. We assumed that the dissolving layer consisted of water ice forming substantial layers, in fact entirely frozen seas of several km depth. We have simulated this geometry by using bentonite and flour layers (in different experiments) overlying layers of ice in which a resistant coil was used to simulate a dyke. We used different thicknesses of bentonite and flour overlying ice layers again of various thicknesses. The flour seems to simulate the Martian crust better because on Mars, g is only about 3/8ths of its value on Earth, so (for equal crustal density) the depth to which the cohesion term C remains important in the Mohr-Coulomb shear failure criterion is about 8/3 times greater. As examples we show two of those experiments in which both the rock analogue and ice layers were of 1.5 cm. thick. Perfect analogues of the Valles Marineris formed above the dyke analogue thermal source complete with the near-linear structure, overall flat spindle shape, cuspate margins, a central ridge, parallel side faults, parallel depressions resembling the Tithonium Chasma. When water was allowed to drain from the beginning, closed depressions formed that have an amazing resemblance to Hebes chasma. We postulate that the entire system of chasmae here discussed formed atop a major dyke swarm some 4000 km length, not dissimilar to the 3500 km long Mesoproterozoic (Ectasian) dyke swarm disrupting the Canadian Shield.

Extendability of parallel sections in vector bundles

NASA Astrophysics Data System (ADS)

Kirschner, Tim

2016-01-01

I address the following question: Given a differentiable manifold M, what are the open subsets U of M such that, for all vector bundles E over M and all linear connections ∇ on E, any ∇-parallel section in E defined on U extends to a ∇-parallel section in E defined on M? For simply connected manifolds M (among others) I describe the entirety of all such sets U which are, in addition, the complement of a C1 submanifold, boundary allowed, of M. This delivers a partial positive answer to a problem posed by Antonio J. Di Scala and Gianni Manno (2014). Furthermore, in case M is an open submanifold of Rn, n ≥ 2, I prove that the complement of U in M, not required to be a submanifold now, can have arbitrarily large n-dimensional Lebesgue measure.

ATDM LANL FleCSI: Topology and Execution Framework

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

Bergen, Benjamin Karl

FleCSI is a compile-time configurable C++ framework designed to support multi-physics application development. As such, FleCSI attempts to provide a very general set of infrastructure design patterns that can be specialized and extended to suit the needs of a broad variety of solver and data requirements. This means that FleCSI is potentially useful to many different ECP projects. Current support includes multidimensional mesh topology, mesh geometry, and mesh adjacency information, n-dimensional hashed-tree data structures, graph partitioning interfaces, and dependency closures (to identify data dependencies between distributed-memory address spaces). FleCSI introduces a functional programming model with control, execution, and data abstractionsmore » that are consistent with state-of-the-art task-based runtimes such as Legion and Charm++. The model also provides support for fine-grained, data-parallel execution with backend support for runtimes such as OpenMP and C++17. The FleCSI abstraction layer provides the developer with insulation from the underlying runtimes, while allowing support for multiple runtime systems, including conventional models like asynchronous MPI. The intent is to give developers a concrete set of user-friendly programming tools that can be used now, while allowing flexibility in choosing runtime implementations and optimizations that can be applied to architectures and runtimes that arise in the future. This project is essential to the ECP Ristra Next-Generation Code project, part of ASC ATDM, because it provides a hierarchically parallel programming model that is consistent with the design of modern system architectures, but which allows for the straightforward expression of algorithmic parallelism in a portably performant manner.« less

Long-time self-diffusion of charged spherical colloidal particles in parallel planar layers.

PubMed

Contreras-Aburto, Claudio; Báez, César A; Méndez-Alcaraz, José M; Castañeda-Priego, Ramón

2014-06-28

The long-time self-diffusion coefficient, D(L), of charged spherical colloidal particles in parallel planar layers is studied by means of Brownian dynamics computer simulations and mode-coupling theory. All particles (regardless which layer they are located on) interact with each other via the screened Coulomb potential and there is no particle transfer between layers. As a result of the geometrical constraint on particle positions, the simulation results show that D(L) is strongly controlled by the separation between layers. On the basis of the so-called contraction of the description formalism [C. Contreras-Aburto, J. M. Méndez-Alcaraz, and R. Castañeda-Priego, J. Chem. Phys. 132, 174111 (2010)], the effective potential between particles in a layer (the so-called observed layer) is obtained from integrating out the degrees of freedom of particles in the remaining layers. We have shown in a previous work that the effective potential performs well in describing the static structure of the observed layer (loc. cit.). In this work, we find that the D(L) values determined from the simulations of the observed layer, where the particles interact via the effective potential, do not agree with the exact values of D(L). Our findings confirm that even when an effective potential can perform well in describing the static properties, there is no guarantee that it will correctly describe the dynamic properties of colloidal systems.

Parallel computation with the force

NASA Technical Reports Server (NTRS)

Jordan, H. F.

1985-01-01

A methodology, called the force, supports the construction of programs to be executed in parallel by a force of processes. The number of processes in the force is unspecified, but potentially very large. The force idea is embodied in a set of macros which produce multiproceossor FORTRAN code and has been studied on two shared memory multiprocessors of fairly different character. The method has simplified the writing of highly parallel programs within a limited class of parallel algorithms and is being extended to cover a broader class. The individual parallel constructs which comprise the force methodology are discussed. Of central concern are their semantics, implementation on different architectures and performance implications.

Design of co-existence parallel periodic surface structure induced by picosecond laser pulses on the Al/Ti multilayers

NASA Astrophysics Data System (ADS)

Petrović, Suzana; Peruško, D.; Kovač, J.; Panjan, P.; Mitrić, M.; Pjević, D.; Kovačević, A.; Jelenković, B.

2017-09-01

Formation of periodic nanostructures on the Ti/5x(Al/Ti)/Si multilayers induced by picosecond laser pulses is studied in order to better understand the formation of a laser-induced periodic surface structure (LIPSS). At fluence slightly below the ablation threshold, the formation of low spatial frequency-LIPSS (LSFL) oriented perpendicular to the direction of the laser polarization is observed on the irradiated area. Prolonged irradiation while scanning results in the formation of a high spatial frequency-LIPSS (HSFL), on top of the LSFLs, creating a co-existence parallel periodic structure. HSFL was oriented parallel to the incident laser polarization. Intermixing between the Al and Ti layers with the formation of Al-Ti intermetallic compounds was achieved during the irradiation. The intermetallic region was formed mostly within the heat affected zone of the sample. Surface segregation of aluminium with partial ablation of the top layer of titanium was followed by the formation of an ultra-thin Al2O3 film on the surface of the multi-layered structure.

Automatic Generation of Directive-Based Parallel Programs for Shared Memory Parallel Systems

NASA Technical Reports Server (NTRS)

Jin, Hao-Qiang; Yan, Jerry; Frumkin, Michael

2000-01-01

The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. As great progress was made in hardware and software technologies, performance of parallel programs with compiler directives has demonstrated large improvement. The introduction of OpenMP directives, the industrial standard for shared-memory programming, has minimized the issue of portability. Due to its ease of programming and its good performance, the technique has become very popular. In this study, we have extended CAPTools, a computer-aided parallelization toolkit, to automatically generate directive-based, OpenMP, parallel programs. We outline techniques used in the implementation of the tool and present test results on the NAS parallel benchmarks and ARC3D, a CFD application. This work demonstrates the great potential of using computer-aided tools to quickly port parallel programs and also achieve good performance.

Final Report for Project DE-FC02-06ER25755 [Pmodels2

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

Panda, Dhabaleswar; Sadayappan, P.

2014-03-12

In this report, we describe the research accomplished by the OSU team under the Pmodels2 project. The team has worked on various angles: designing high performance MPI implementations on modern networking technologies (Mellanox InfiniBand (including the new ConnectX2 architecture and Quad Data Rate), QLogic InfiniPath, the emerging 10GigE/iWARP and RDMA over Converged Enhanced Ethernet (RoCE) and Obsidian IB-WAN), studying MPI scalability issues for multi-thousand node clusters using XRC transport, scalable job start-up, dynamic process management support, efficient one-sided communication, protocol offloading and designing scalable collective communication libraries for emerging multi-core architectures. New designs conforming to the Argonne’s Nemesis interface havemore » also been carried out. All of these above solutions have been integrated into the open-source MVAPICH/MVAPICH2 software. This software is currently being used by more than 2,100 organizations worldwide (in 71 countries). As of January ’14, more than 200,000 downloads have taken place from the OSU Web site. In addition, many InfiniBand vendors, server vendors, system integrators and Linux distributors have been incorporating MVAPICH/MVAPICH2 into their software stacks and distributing it. Several InfiniBand systems using MVAPICH/MVAPICH2 have obtained positions in the TOP500 ranking of supercomputers in the world. The latest November ’13 ranking include the following systems: 7th ranked Stampede system at TACC with 462,462 cores; 11th ranked Tsubame 2.5 system at Tokyo Institute of Technology with 74,358 cores; 16th ranked Pleiades system at NASA with 81,920 cores; Work on PGAS models has proceeded on multiple directions. The Scioto framework, which supports task-parallelism in one-sided and global-view parallel programming, has been extended to allow multi-processor tasks that are executed by processor groups. A quantum Monte Carlo application is being ported onto the extended Scioto framework. A public release of Global Trees (GT) has been made, along with the Global Chunks (GC) framework on which GT is built. The Global Chunks (GC) layer is also being used as the basis for the development of a higher level Global Graphs (GG) layer. The Global Graphs (GG) system will provide a global address space view of distributed graph data structures on distributed memory systems.« less

Solare Cell Roof Tile And Method Of Forming Same

DOEpatents

Hanoka, Jack I.; Real, Markus

1999-11-16

A solar cell roof tile includes a front support layer, a transparent encapsulant layer, a plurality of interconnected solar cells and a backskin layer. The front support layer is formed of light transmitting material and has first and second surfaces. The transparent encapsulant layer is disposed adjacent the second surface of the front support layer. The interconnected solar cells has a first surface disposed adjacent the transparent encapsulant layer. The backskin layer has a first surface disposed adjacent a second surface of the interconnected solar cells, wherein a portion of the backskin layer wraps around and contacts the first surface of the front support layer to form the border region. A portion of the border region has an extended width. The solar cell roof tile may have stand-offs disposed on the extended width border region for providing vertical spacing with respect to an adjacent solar cell roof tile.

Simplified and quick electrical modeling for dye sensitized solar cells: An experimental and theoretical investigation

NASA Astrophysics Data System (ADS)

de Andrade, Rocelito Lopes; de Oliveira, Matheus Costa; Kohlrausch, Emerson Cristofer; Santos, Marcos José Leite

2018-05-01

This work presents a new and simple method for determining IPH (current source dependent on luminance), I0 (reverse saturation current), n (ideality factor), RP and RS, (parallel and series resistance) to build an electrical model for dye sensitized solar cells (DSSCs). The electrical circuit parameters used in the simulation and to generate theoretical curves for the single diode electrical model were extracted from I-V curves of assembled DSSCs. Model validation was performed by assembling five different types of DSSCs and evaluating the following parameters: effect of a TiO2 blocking/adhesive layer, thickness of the TiO2 layer and the presence of a light scattering layer. In addition, irradiance, temperature, series and parallel resistance, ideality factor and reverse saturation current were simulated.

Three-dimensional magnetic bubble memory system

NASA Technical Reports Server (NTRS)

Stadler, Henry L. (Inventor); Katti, Romney R. (Inventor); Wu, Jiin-Chuan (Inventor)

1994-01-01

A compact memory uses magnetic bubble technology for providing data storage. A three-dimensional arrangement, in the form of stacks of magnetic bubble layers, is used to achieve high volumetric storage density. Output tracks are used within each layer to allow data to be accessed uniquely and unambiguously. Storage can be achieved using either current access or field access magnetic bubble technology. Optical sensing via the Faraday effect is used to detect data. Optical sensing facilitates the accessing of data from within the three-dimensional package and lends itself to parallel operation for supporting high data rates and vector and parallel processing.

Parallel inhomogeneity and the Alfven resonance. 1: Open field lines

NASA Technical Reports Server (NTRS)

Hansen, P. J.; Harrold, B. G.

1994-01-01

In light of a recent demonstration of the general nonexistence of a singularity at the Alfven resonance in cold, ideal, linearized magnetohydrodynamics, we examine the effect of a small density gradient parallel to uniform, open ambient magnetic field lines. To lowest order, energy deposition is quantitatively unaffected but occurs continuously over a thickened layer. This effect is illustrated in a numerical analysis of a plasma sheet boundary layer model with perfectly absorbing boundary conditions. Consequences of the results are discussed, both for the open field line approximation and for the ensuing closed field line analysis.

High-pressure synthesis and crystal structures of the strontium oxogallates Sr2Ga2O5 and Sr5Ga6O14

NASA Astrophysics Data System (ADS)

Kahlenberg, Volker; Goettgens, Valerie; Mair, Philipp; Schmidmair, Daniela

2015-08-01

High-pressure synthesis experiments in a piston-cylinder apparatus at 1.5 GPa/3.0 GPa and 1000 °C resulted in the formation of single-crystals of Sr2Ga2O5 and Sr5Ga6O14, respectively. The structures of both compounds have been solved from single-crystal diffraction data sets using direct methods. The first compound is orthorhombic with space group type Pbca (a=10.0021(4) Å, b=9.601(4) Å, c=10.6700(4) Å, V=1024.6(4) Å3, Mr=394.68 u, Z=8, Dx=5.12 g/cm3) and belongs to the group of single layer gallates. Individual sheets are parallel to (0 0 1) and can be built from the condensation of unbranched vierer single chains running along [0 1 0]. The layers are characterized by the presence of four- and strongly elliptical eight-membered rings of corner connected tetrahedra in UUDD and UUUUDDDD conformation. Strontium atoms are sandwiched between the tetrahedral layers for charge compensation and are coordinated by six and seven oxygen ligands, respectively. Sr2Ga2O5 is isotypic with several other double sulfides and selenides. To the best of our knowledge, it is the first example of an oxide with this structure type. From a structural point of view, Sr5Ga6O14 is a phyllogallate as well. The crystal structure adopts the monoclinic space group P21/c (a=8.1426(3) Å, b=8.1803(3) Å, c=10.8755(4) Å, β=91.970(4)° V=723.98(5) Å3, Mr=1080.42 u, Z=2, Dx=4.96 g/cm3). Individual sheets extend along (0 0 1). Basic building units are unbranched dreier single chains parallel to [1 0 0]. The layers contain tertiary (Q3) und quaternary (Q4) connected [GaO4]-tetrahedra in the ratio 2:1 resulting in a Ga:O ratio of 3:7 and the formation of exclusively five-membered rings. Linkage between adjacent tetrahedral sheets is provided by three symmetrically independent strontium ions which are surrounded by six to eight oxygen atoms. The layers in Sr5Ga6O14 are similar to those observed in the melilite structure-type. Crystallochemical relationships between the present phases and other known compounds are discussed in detail.

Radiative instabilities in sheared magnetic field

NASA Technical Reports Server (NTRS)

Drake, J. F.; Sparks, L.; Van Hoven, G.

1988-01-01

The structure and growth rate of the radiative instability in a sheared magnetic field B have been calculated analytically using the Braginskii fluid equations. In a shear layer, temperature and density perturbations are linked by the propagation of sound waves parallel to the local magnetic field. As a consequence, density clumping or condensation plays an important role in driving the instability. Parallel thermal conduction localizes the mode to a narrow layer where K(parallel) is small and stabilizes short wavelengths k larger-than(c) where k(c) depends on the local radiation and conduction rates. Thermal coupling to ions also limits the width of the unstable spectrum. It is shown that a broad spectrum of modes is typically unstable in tokamak edge plasmas and it is argued that this instability is sufficiently robust to drive the large-amplitude density fluctuations often measured there.

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

Foltyn, Stephen R; Jia, Quanxi; Arendt, Paul N

A superconducting tape having reduced AC losses. The tape has a high temperature superconductor layer that is segmented. Disruptive strips, formed in one of the tape substrate, a buffer layer, and the superconducting layer create parallel discontinuities in the superconducting layer that separate the current-carrying elements of the superconducting layer into strips or filament-like structures. Segmentation of the current-carrying elements has the effect of reducing AC current losses. Methods of making such a superconducting tape and reducing AC losses in such tapes are also disclosed.

The influence of the Hall term on the development of magnetized laser-produced plasma jets

NASA Astrophysics Data System (ADS)

Hamlin, N. D.; Seyler, C. E.; Khiar, B.

2018-04-01

We present 2D axisymmetric simulation results describing the influence of the Hall term on laser-produced plasma jets and their interaction with an applied magnetic field parallel to the laser axis. Bending of the poloidal B-field lines produces an MHD shock structure surrounding a conical cavity, and a jet is produced from the convergence of the shock envelope. Both the jet and the conical cavity underneath it are bound by fast MHD shocks. We compare the MHD results generated using the extended-MHD code Physics as an Extended-MHD Relaxation System with an Efficient Upwind Scheme (PERSEUS) with MHD results generated using GORGON and find reasonable agreement. We then present extended-MHD results generated using PERSEUS, which show that the Hall term has several effects on the plasma jet evolution. A hot low-density current-carrying layer of plasma develops just outside the plume, which results in a helical rather than a purely poloidal B-field, and reduces magnetic stresses, resulting in delayed flow convergence and jet formation. The flow is partially frozen into the helical field, resulting in azimuthal rotation of the jet. The Hall term also produces field-aligned current in strongly magnetized regions. In particular, we find the influence of Hall physics on this problem to be scale-dependent. This points to the importance of mitigating the Hall effect in a laboratory setup, by increasing the jet density and system dimensions, in order to avoid inaccurate extrapolation to astrophysical scales.

Turbulent Flow Over Large Roughness Elements: Effect of Frontal and Plan Solidity on Turbulence Statistics and Structure

NASA Astrophysics Data System (ADS)

Placidi, M.; Ganapathisubramani, B.

2018-04-01

Wind-tunnel experiments were carried out on fully-rough boundary layers with large roughness (δ /h ≈ 10, where h is the height of the roughness elements and δ is the boundary-layer thickness). Twelve different surface conditions were created by using LEGO™ bricks of uniform height. Six cases are tested for a fixed plan solidity (λ _P) with variations in frontal density (λ _F), while the other six cases have varying λ _P for fixed λ _F. Particle image velocimetry and floating-element drag-balance measurements were performed. The current results complement those contained in Placidi and Ganapathisubramani (J Fluid Mech 782:541-566, 2015), extending the previous analysis to the turbulence statistics and spatial structure. Results indicate that mean velocity profiles in defect form agree with Townsend's similarity hypothesis with varying λ _F, however, the agreement is worse for cases with varying λ _P. The streamwise and wall-normal turbulent stresses, as well as the Reynolds shear stresses, show a lack of similarity across most examined cases. This suggests that the critical height of the roughness for which outer-layer similarity holds depends not only on the height of the roughness, but also on the local wall morphology. A new criterion based on shelter solidity, defined as the sheltered plan area per unit wall-parallel area, which is similar to the `effective shelter area' in Raupach and Shaw (Boundary-Layer Meteorol 22:79-90, 1982), is found to capture the departure of the turbulence statistics from outer-layer similarity. Despite this lack of similarity reported in the turbulence statistics, proper orthogonal decomposition analysis, as well as two-point spatial correlations, show that some form of universal flow structure is present, as all cases exhibit virtually identical proper orthogonal decomposition mode shapes and correlation fields. Finally, reduced models based on proper orthogonal decomposition reveal that the small scales of the turbulence play a significant role in assessing outer-layer similarity.

Waves on the Free Surface Described by Linearized Equations of Hydrodynamics with Localized Right-Hand Sides

NASA Astrophysics Data System (ADS)

Dobrokhotov, S. Yu.; Nazaikinskii, V. E.

2018-01-01

A linearized system of equations of hydrodynamics with time-dependent spatially localized right-hand side placed both on the free surface (and on the bottom of the basin) and also in the layer of the liquid is considered in a layer of variable depth with a given basic plane-parallel flow. A method of constructing asymptotic solutions of this problem is suggested; it consists of two stages: (1) a reduction of the three-dimensional problem to a two-dimensional inhomogeneous pseudodifferential equation on the nonperturbed free surface of the liquid, (2) a representation of the localized right-hand side in the form of a Maslov canonical operator on a special Lagrangian manifold and the subsequent application of a generalization to evolution problems of an approach, which was recently suggested in the paper [A. Yu. Anikin, S. Yu. Dobrokhotov, V. E. Nazaikinskii, and M. Rouleux, Dokl. Ross. Akad. Nauk 475 (6), 624-628 (2017); Engl. transl.: Dokl. Math. 96 (1), 406-410 (2017)], to solving stationary problems with localized right-hand sides and its combination with "nonstandard" characteristics. A method of calculation (generalizing long-standing results of Dobrokhotov and Zhevandrov) of an analog of the Kelvin wedge and the wave fields inside the wedge and in its neighborhood is suggested, which uses the consideration that this method is the projection to the extended configuration space of a Lagrangian manifold formed by the trajectories of the Hamiltonian vector field issuing from the intersection of the set of zeros of the extended Hamiltonian of the problem with conormal bundle to the graph of the vector function defining the trajectory of motion of an equivalent source on the surface of the liquid.

Solar panel truss mounting systems and methods

DOEpatents

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2015-10-20

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

Solar panel truss mounting systems and methods

DOEpatents

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2016-06-28

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

Turbulent boundary layers with secondary flow

NASA Technical Reports Server (NTRS)

Grushwitz, E.

1984-01-01

An experimental analysis of the boundary layer on a plane wall, along which the flow occurs, whose potential flow lines are curved in plane parallel to the wall is discussed. According to the equation frequently applied to boundary layers in a plane flow, which is usually obtained by using the pulse law, a generalization is derived which is valid for boundary layers with spatial flow. The wall shear stresses were calculated with this equation.

The Relation between Reconnected Flux, the Parallel Electric Field, and the Reconnection Rate in a Three-Dimensional Kinetic Simulation of Magnetic Reconnection

NASA Astrophysics Data System (ADS)

Wendel, D. E.; Olson, D. K.; Hesse, M.; Karimabadi, H.; Daughton, W. S.

2013-12-01

We investigate the distribution of parallel electric fields and their relationship to the location and rate of magnetic reconnection of a large particle-in-cell simulation of 3D turbulent magnetic reconnection with open boundary conditions. The simulation's guide field geometry inhibits the formation of topological features such as separators and null points. Therefore, we derive the location of potential changes in magnetic connectivity by finding the field lines that experience a large relative change between their endpoints, i.e., the quasi-separatrix layer. We find a correspondence between the locus of changes in magnetic connectivity, or the quasi-separatrix layer, and the map of large gradients in the integrated parallel electric field (or quasi-potential). Furthermore, we compare the distribution of parallel electric fields along field lines with the reconnection rate. We find the reconnection rate is controlled by only the low-amplitude, zeroth and first-order trends in the parallel electric field, while the contribution from high amplitude parallel fluctuations, such as electron holes, is negligible. The results impact the determination of reconnection sites within models of 3D turbulent reconnection as well as the inference of reconnection rates from in situ spacecraft measurements. It is difficult through direct observation to isolate the locus of the reconnection parallel electric field amidst the large amplitude fluctuations. However, we demonstrate that a positive slope of the partial sum of the parallel electric field along the field line as a function of field line length indicates where reconnection is occurring along the field line.

Ion manipulation device with electrical breakdown protection

DOEpatents

Chen, Tsung-Chi; Tang, Keqi; Ibrahim, Yehia M; Smith, Richard D; Anderson, Gordon A; Baker, Erin M

2014-12-02

An ion manipulation method and device is disclosed. The device includes a pair of substantially parallel surfaces. An array of inner electrodes is contained within, and extends substantially along the length of, each parallel surface. The device includes a first outer array of electrodes and a second outer array of electrodes. Each outer array of electrodes is positioned on either side of the inner electrodes, and is contained within and extends substantially along the length of each parallel surface. A DC voltage is applied to the first and second outer array of electrodes. A RF voltage, with a superimposed electric field, is applied to the inner electrodes by applying the DC voltages to each electrode. Ions either move between the parallel surfaces within an ion confinement area or along paths in the direction of the electric field, or can be trapped in the ion confinement area. The surfaces are housed in a chamber, and at least one electrically insulative shield is coupled to an inner surface of the chamber for increasing a mean-free-path between two adjacent electrodes in the chamber.

The new moon illusion and the role of perspective in the perception of straight and parallel lines.

PubMed

Rogers, Brian; Naumenko, Olga

2015-01-01

In the new moon illusion, the sun does not appear to be in a direction perpendicular to the boundary between the lit and dark sides of the moon, and aircraft jet trails appear to follow curved paths across the sky. In both cases, lines that are physically straight and parallel to the horizon appear to be curved. These observations prompted us to investigate the neglected question of how we are able to judge the straightness and parallelism of extended lines. To do this, we asked observers to judge the 2-D alignment of three artificial "stars" projected onto the dome of the Saint Petersburg Planetarium that varied in both their elevation and their separation in horizontal azimuth. The results showed that observers make substantial, systematic errors, biasing their judgments away from the veridical great-circle locations and toward equal-elevation settings. These findings further demonstrate that whenever information about the distance of extended lines or isolated points is insufficient, observers tend to assume equidistance, and as a consequence, their straightness judgments are biased toward the angular separation of straight and parallel lines.

Chemical and Mineralogical Characterization of a Hematite-bearing Ridge on Mauna Kea, Hawaii: A Potential Mineralogical Process Analog for the Mount Sharp Hematite Ridge

NASA Technical Reports Server (NTRS)

Graff, T. G.; Morris, R. V.; Ming, D. W.; Hamilton, J. C.; Adams, M.; Fraeman, A. A.; Arvidson, R. E.; Catalano, J. G.; Mertzman, S. A.

2014-01-01

The Mars Science Laboratory (MSL) rover Curiosity landed in Gale Crater in August 2012 and is currently roving towards the layered central mound known as Mount Sharp [1]. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) hyperspectral data indicate Mount Sharp contains an 5 km stratigraphic sequence including Fe-Mg smectites, hematite, and hydrated sulfates in the lower layers separated by an unconformity from the overlying anhydrous strata [1,2,3]. Hematite was initially detected in CRISM data to occur in the lower sulfate layers on the north side of the mound [2]. [3] further mapped a distinct hematite detection occurring as part of a 200 m wide ridge that extends 6.5 km NE-SW, approximately parallel with the base of Mount Sharp. It is likely a target for in-situ analyses by Curiosity. We document here the occurrence of a stratum of hematite-bearing breccia that is exposed on the Puu Poliahu cinder cone near the summit of Mauna Kea volcano (Hawaii) (Fig.1). The stratum is more resistant to weathering than surrounding material, giving it the appearance of a ridge. The Mauna Kea hematite ridge is thus arguably a potential terrestrial mineralogical and process analog for the Gale Crater hematite ridge. We are acquiring a variety of chemical and mineralogical data on the Mauna Kea samples, with a focus on the chemical and mineralogical information already available or planned for the Gale hematite ridge.

Entropy generation in a parallel-plate active magnetic regenerator with insulator layers

NASA Astrophysics Data System (ADS)

Mugica Guerrero, Ibai; Poncet, Sébastien; Bouchard, Jonathan

2017-02-01

This paper proposes a feasible solution to diminish conduction losses in active magnetic regenerators. Higher performances of these machines are linked to a lower thermal conductivity of the Magneto-Caloric Material (MCM) in the streamwise direction. The concept presented here involves the insertion of insulator layers along the length of a parallel-plate magnetic regenerator in order to reduce the heat conduction within the MCM. This idea is investigated by means of a 1D numerical model. This model solves not only the energy equations for the fluid and solid domains but also the magnetic circuit that conforms the experimental setup of reference. In conclusion, the addition of insulator layers within the MCM increases the temperature span, cooling load, and coefficient of performance by a combination of lower heat conduction losses and an increment of the global Magneto-Caloric Effect. The generated entropy by solid conduction, fluid convection, and conduction and viscous losses are calculated to help understand the implications of introducing insulator layers in magnetic regenerators. Finally, the optimal number of insulator layers is studied.

Dynamical Generation of Quasi-Stationary Alfvenic Double Layers and Charge Holes and Unified Theory of Quasi-Static and Alfvenic Auroral Arc Formation

NASA Astrophysics Data System (ADS)

Song, Y.; Lysak, R. L.

2015-12-01

Parallel E-fields play a crucial role for the acceleration of charged particles, creating discrete aurorae. However, once the parallel electric fields are produced, they will disappear right away, unless the electric fields can be continuously generated and sustained for a fairly long time. Thus, the crucial question in auroral physics is how to generate such a powerful and self-sustained parallel electric fields which can effectively accelerate charge particles to high energy during a fairly long time. We propose that nonlinear interaction of incident and reflected Alfven wave packets in inhomogeneous auroral acceleration region can produce quasi-stationary non-propagating electromagnetic plasma structures, such as Alfvenic double layers (DLs) and Charge Holes. Such Alfvenic quasi-static structures often constitute powerful high energy particle accelerators. The Alfvenic DL consists of localized self-sustained powerful electrostatic electric fields nested in a low density cavity and surrounded by enhanced magnetic and mechanical stresses. The enhanced magnetic and velocity fields carrying the free energy serve as a local dynamo, which continuously create the electrostatic parallel electric field for a fairly long time. The generated parallel electric fields will deepen the seed low density cavity, which then further quickly boosts the stronger parallel electric fields creating both Alfvenic and quasi-static discrete aurorae. The parallel electrostatic electric field can also cause ion outflow, perpendicular ion acceleration and heating, and may excite Auroral Kilometric Radiation.

Monolayers and multilayers of conjugated polymers as nanosized electronic components.

PubMed

Zotti, Gianni; Vercelli, Barbara; Berlin, Anna

2008-09-01

Conjugated polymers (CPs) are interesting materials for preparing devices based on nanoscopic molecular architectures because they exhibit electrical, electronic, magnetic, and optical properties similar to those of metals or semiconductors while maintaining the flexibility and ease of processing of polymers. The production of well-defined mono- and multilayers of CPs on electrodes with nanometer-scale, one-dimensional resolution remains, however, an important challenge. In this Account, we describe the preparation and conductive properties of nanometer-sized CP molecular structures formed on electrode surfaces--namely, self-assembled monolayer (SAM), brush-type, and self-assembled multilayer CPs--and in combination with gold nanoparticles (AuNPs). We have electrochemically polymerized SAMs of carboxyalkyl-functionalized terthiophenes aligned either perpendicular or parallel to the electrode surface. Anodic coupling of various pyrrole- and thiophene-based monomers in solution with the oligothiophene-based SAMs produced brush-like films. Microcontact printing of these SAMs produced patterns that, after heterocoupling, exhibited large height enhancements, as measured using atomic force microscopy (AFM). We have employed layer-by-layer self-assembly of water-soluble polythiophene-based polyelectrolytes to form self-assembled multilayers. The combination of isostructural polycationic and polyanionic polythiophenes produced layers of chains aligned parallel to the substrate plane. These stable, robust, and dense layers formed with high regularity on the preformed monolayers, with minimal interchain penetration. Infrared reflection/adsorption spectroscopy and X-ray diffraction analyses revealed unprecedented degrees of order. Deposition of soluble polypyrroles produced molecular layers that, when analyzed using a gold-coated AFM tip, formed gold-polymer-gold junctions that were either ohmic or rectifying, depending of the layer sequence. We also describe the electronic conduction of model alpha,omega-capped sexithiophenes featuring a range of electron donor/acceptor units and lengths of additional conjugation. The sexithiophene cores exhibit redox-type conductivity, developing at the neutral/cation and cation/dication levels with values depending the nature of the substitution and the redox system. Extending the conjugation beyond the sexithiophene frame introduces further oxidation processes displaying enhanced conductivity. Finally, we discuss the ability of CP-based monolayers to coordinate AuNPs. Although thiophene- and pyrrole-based oligomers aggregate toluene-soluble AuNPs, alkyl substitution inhibits the aggregation process through steric restraint. Consequently, we investigated the interactions between AuNPs and polypyrrole or polythiophene monolayers, including those formed from star-shaped molecules. The hindered aggregation provided by alkyl substituents allowed us to adsorb thiol-functionalized oligothiophenes and oligopyrroles directly onto preformed AuNPs. Novel materials incorporating AuNPs of the same size but bearing different conjugated ends or bridges have great promise for applications in electrocatalysis, electroanalysis, and organic electronics.

Extended computational kernels in a massively parallel implementation of the Trotter-Suzuki approximation

NASA Astrophysics Data System (ADS)

Wittek, Peter; Calderaro, Luca

2015-12-01

We extended a parallel and distributed implementation of the Trotter-Suzuki algorithm for simulating quantum systems to study a wider range of physical problems and to make the library easier to use. The new release allows periodic boundary conditions, many-body simulations of non-interacting particles, arbitrary stationary potential functions, and imaginary time evolution to approximate the ground state energy. The new release is more resilient to the computational environment: a wider range of compiler chains and more platforms are supported. To ease development, we provide a more extensive command-line interface, an application programming interface, and wrappers from high-level languages.

LMFAO! Humor as a Response to Fear: Decomposing Fear Control within the Extended Parallel Process Model

PubMed Central

Abril, Eulàlia P.; Szczypka, Glen; Emery, Sherry L.

2017-01-01

This study seeks to analyze fear control responses to the 2012 Tips from Former Smokers campaign using the Extended Parallel Process Model (EPPM). The goal is to examine the occurrence of ancillary fear control responses, like humor. In order to explore individuals’ responses in an organic setting, we use Twitter data—tweets—collected via the Firehose. Content analysis of relevant fear control tweets (N = 14,281) validated the existence of boomerang responses within the EPPM: denial, defensive avoidance, and reactance. More importantly, results showed that humor tweets were not only a significant occurrence but constituted the majority of fear control responses. PMID:29527092

Automatic Generation of OpenMP Directives and Its Application to Computational Fluid Dynamics Codes

NASA Technical Reports Server (NTRS)

Yan, Jerry; Jin, Haoqiang; Frumkin, Michael; Yan, Jerry (Technical Monitor)

2000-01-01

The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. As great progress was made in hardware and software technologies, performance of parallel programs with compiler directives has demonstrated large improvement. The introduction of OpenMP directives, the industrial standard for shared-memory programming, has minimized the issue of portability. In this study, we have extended CAPTools, a computer-aided parallelization toolkit, to automatically generate OpenMP-based parallel programs with nominal user assistance. We outline techniques used in the implementation of the tool and discuss the application of this tool on the NAS Parallel Benchmarks and several computational fluid dynamics codes. This work demonstrates the great potential of using the tool to quickly port parallel programs and also achieve good performance that exceeds some of the commercial tools.

Adding Data Management Services to Parallel File Systems

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

Brandt, Scott

2015-03-04

The objective of this project, called DAMASC for “Data Management in Scientific Computing”, is to coalesce data management with parallel file system management to present a declarative interface to scientists for managing, querying, and analyzing extremely large data sets efficiently and predictably. Managing extremely large data sets is a key challenge of exascale computing. The overhead, energy, and cost of moving massive volumes of data demand designs where computation is close to storage. In current architectures, compute/analysis clusters access data in a physically separate parallel file system and largely leave it scientist to reduce data movement. Over the past decadesmore » the high-end computing community has adopted middleware with multiple layers of abstractions and specialized file formats such as NetCDF-4 and HDF5. These abstractions provide a limited set of high-level data processing functions, but have inherent functionality and performance limitations: middleware that provides access to the highly structured contents of scientific data files stored in the (unstructured) file systems can only optimize to the extent that file system interfaces permit; the highly structured formats of these files often impedes native file system performance optimizations. We are developing Damasc, an enhanced high-performance file system with native rich data management services. Damasc will enable efficient queries and updates over files stored in their native byte-stream format while retaining the inherent performance of file system data storage via declarative queries and updates over views of underlying files. Damasc has four key benefits for the development of data-intensive scientific code: (1) applications can use important data-management services, such as declarative queries, views, and provenance tracking, that are currently available only within database systems; (2) the use of these services becomes easier, as they are provided within a familiar file-based ecosystem; (3) common optimizations, e.g., indexing and caching, are readily supported across several file formats, avoiding effort duplication; and (4) performance improves significantly, as data processing is integrated more tightly with data storage. Our key contributions are: SciHadoop which explores changes to MapReduce assumption by taking advantage of semantics of structured data while preserving MapReduce’s failure and resource management; DataMods which extends common abstractions of parallel file systems so they become programmable such that they can be extended to natively support a variety of data models and can be hooked into emerging distributed runtimes such as Stanford’s Legion; and Miso which combines Hadoop and relational data warehousing to minimize time to insight, taking into account the overhead of ingesting data into data warehousing.« less

Anomalous transport in discrete arcs and simulation of double layers in a model auroral circuit

NASA Technical Reports Server (NTRS)

Smith, Robert A.

1987-01-01

The evolution and long-time stability of a double layer (DL) in a discrete auroral arc requires that the parallel current in the arc, which may be considered uniform at the source, be diverted within the arc to charge the flanks of the U-shaped double layer potential structure. A simple model is presented in which this current redistribution is effected by anomalous transport based on electrostatic lower hybrid waves driven by the flank structure itself. This process provides the limiting constraint on the double layer potential. The flank charging may be represented as that of a nonlinear transmission line. A simplified model circuit, in which the transmission line is represented by a nonlinear impedance in parallel with a variable resistor, is incorporated in a one-dimensional simulation model to give the current density at the DL boundaries. Results are presented for the scaling of the DL potential as a function of the width of the arc and the saturation efficiency of the lower hybrid instability mechanism.

Anomalous transport in discrete arcs and simulation of double layers in a model auroral circuit

NASA Technical Reports Server (NTRS)

Smith, Robert A.

1987-01-01

The evolution and long-time stability of a double layer in a discrete auroral arc requires that the parallel current in the arc, which may be considered uniform at the source, be diverted within the arc to charge the flanks of the U-shaped double-layer potential structure. A simple model is presented in which this current re-distribution is effected by anomalous transport based on electrostatic lower hybrid waves driven by the flank structure itself. This process provides the limiting constraint on the double-layer potential. The flank charging may be represented as that of a nonlinear transmission. A simplified model circuit, in which the transmission line is represented by a nonlinear impedance in parallel with a variable resistor, is incorporated in a 1-d simulation model to give the current density at the DL boundaries. Results are presented for the scaling of the DL potential as a function of the width of the arc and the saturation efficiency of the lower hybrid instability mechanism.

A real time neural net estimator of fatigue life

NASA Technical Reports Server (NTRS)

Troudet, T.; Merrill, W.

1990-01-01

A neural net architecture is proposed to estimate, in real-time, the fatigue life of mechanical components, as part of the Intelligent Control System for Reusable Rocket Engines. Arbitrary component loading values were used as input to train a two hidden-layer feedforward neural net to estimate component fatigue damage. The ability of the net to learn, based on a local strain approach, the mapping between load sequence and fatigue damage has been demonstrated for a uniaxial specimen. Because of its demonstrated performance, the neural computation may be extended to complex cases where the loads are biaxial or triaxial, and the geometry of the component is complex (e.g., turbopump blades). The generality of the approach is such that load/damage mappings can be directly extracted from experimental data without requiring any knowledge of the stress/strain profile of the component. In addition, the parallel network architecture allows real-time life calculations even for high frequency vibrations. Owing to its distributed nature, the neural implementation will be robust and reliable, enabling its use in hostile environments such as rocket engines. This neural net estimator of fatigue life is seen as the enabling technology to achieve component life prognosis, and therefore would be an important part of life extending control for reusable rocket engines.

Neural Networks and other Techniques for Fault Identification and Isolation of Aircraft Systems

NASA Technical Reports Server (NTRS)

Innocenti, M.; Napolitano, M.

2003-01-01

Fault identification, isolation, and accomodation have become critical issues in the overall performance of advanced aircraft systems. Neural Networks have shown to be a very attractive alternative to classic adaptation methods for identification and control of non-linear dynamic systems. The purpose of this paper is to show the improvements in neural network applications achievable through the use of learning algorithms more efficient than the classic Back-Propagation, and through the implementation of the neural schemes in parallel hardware. The results of the analysis of a scheme for Sensor Failure, Detection, Identification and Accommodation (SFDIA) using experimental flight data of a research aircraft model are presented. Conventional approaches to the problem are based on observers and Kalman Filters while more recent methods are based on neural approximators. The work described in this paper is based on the use of neural networks (NNs) as on-line learning non-linear approximators. The performances of two different neural architectures were compared. The first architecture is based on a Multi Layer Perceptron (MLP) NN trained with the Extended Back Propagation algorithm (EBPA). The second architecture is based on a Radial Basis Function (RBF) NN trained with the Extended-MRAN (EMRAN) algorithms. In addition, alternative methods for communications links fault detection and accomodation are presented, relative to multiple unmanned aircraft applications.

Terahertz artificial material based on integrated metal-rod-array for phase sensitive fluid detection.

PubMed

You, Borwen; Chen, Ching-Yu; Yu, Chin-Ping; Liu, Tze-An; Hattori, Toshiaki; Lu, Ja-Yu

2017-04-17

A terahertz artificial material composed of metal rod array is experimentally investigated on its transmission spectral property and successfully incorporated into microfluidics as a miniaturized terahertz waveguide with an extended optical-path-length for label-free fluidic sensing. Theoretical and experimental characterizations of terahertz transmission spectra show that the wave guidance along the metal rod array originates from the resonance of transverse-electric-polarized waves within the metal rod slits. The extended optical path length along three layers of metal-rod-array enables terahertz waves sufficiently overlapping the fluid molecules embedded among the rods, leading to strongly enhanced phase change by approximately one order of magnitude compared with the blank metal-parallel-plate waveguide. Based on the enhanced phase sensitivity, three kinds of colorless liquid analytes, namely, acetone, methanol, and ethanol, with different dipole moments are identified in situ using the metal-rod-array-based microfluidic sensor. The detection limit in molecular amounts of a liquid analyte is experimentally demonstrated to be less than 0.1 mmol, corresponding to 2.7 μmol/mm². The phase sensitive terahertz metal-rod-array-based sensor potentially has good adaptability in lab-chip technology for various practical applications, such as industrial toxic fluid detection and medical breath inspection.

PIXIE3D: A Parallel, Implicit, eXtended MHD 3D Code.

NASA Astrophysics Data System (ADS)

Chacon, L.; Knoll, D. A.

2004-11-01

We report on the development of PIXIE3D, a 3D parallel, fully implicit Newton-Krylov extended primitive-variable MHD code in general curvilinear geometry. PIXIE3D employs a second-order, finite-volume-based spatial discretization that satisfies remarkable properties such as being conservative, solenoidal in the magnetic field, non-dissipative, and stable in the absence of physical dissipation.(L. Chacón , phComput. Phys. Comm.) submitted (2004) PIXIE3D employs fully-implicit Newton-Krylov methods for the time advance. Currently, first and second-order implicit schemes are available, although higher-order temporal implicit schemes can be effortlessly implemented within the Newton-Krylov framework. A successful, scalable, MG physics-based preconditioning strategy, similar in concept to previous 2D MHD efforts,(L. Chacón et al., phJ. Comput. Phys). 178 (1), 15- 36 (2002); phJ. Comput. Phys., 188 (2), 573-592 (2003) has been developed. We are currently in the process of parallelizing the code using the PETSc library, and a Newton-Krylov-Schwarz approach for the parallel treatment of the preconditioner. In this poster, we will report on both the serial and parallel performance of PIXIE3D, focusing primarily on scalability and CPU speedup vs. an explicit approach.

The Complexity of Parallel Algorithms,

DTIC Science & Technology

1985-11-01

programns have been written for se(luiential coiipn ters. Many p~eop~le want coimp ~ilers dihal. will c(nimpile t he, code for parallel machines, to avoid...between two vertices. We also rely on parallel algorithms for maintaining data structures and manipulating graphs. We do not go into the details of these...Jpatlis and maintain connected coimp ~onents. The routine is: - 35 .- ExtendPath(r, Q, V) begin P +-0; s 4- while there is a path in V - P from s to a vertex

Options for Parallelizing a Planning and Scheduling Algorithm

NASA Technical Reports Server (NTRS)

Clement, Bradley J.; Estlin, Tara A.; Bornstein, Benjamin D.

2011-01-01

Space missions have a growing interest in putting multi-core processors onboard spacecraft. For many missions processing power significantly slows operations. We investigate how continual planning and scheduling algorithms can exploit multi-core processing and outline different potential design decisions for a parallelized planning architecture. This organization of choices and challenges helps us with an initial design for parallelizing the CASPER planning system for a mesh multi-core processor. This work extends that presented at another workshop with some preliminary results.

Predicting the stability of a compressible periodic parallel jet flow

NASA Technical Reports Server (NTRS)

Miles, Jeffrey H.

1996-01-01

It is known that mixing enhancement in compressible free shear layer flows with high convective Mach numbers is difficult. One design strategy to get around this is to use multiple nozzles. Extrapolating this design concept in a one dimensional manner, one arrives at an array of parallel rectangular nozzles where the smaller dimension is omega and the longer dimension, b, is taken to be infinite. In this paper, the feasibility of predicting the stability of this type of compressible periodic parallel jet flow is discussed. The problem is treated using Floquet-Bloch theory. Numerical solutions to this eigenvalue problem are presented. For the case presented, the interjet spacing, s, was selected so that s/omega =2.23. Typical plots of the eigenvalue and stability curves are presented. Results obtained for a range of convective Mach numbers from 3 to 5 show growth rates omega(sub i)=kc(sub i)/2 range from 0.25 to 0.29. These results indicate that coherent two-dimensional structures can occur without difficulty in multiple parallel periodic jet nozzles and that shear layer mixing should occur with this type of nozzle design.

Organic hybrid planar-nanocrystalline bulk heterojunctions

DOEpatents

Forrest, Stephen R [Ann Arbor, MI; Yang, Fan [Piscataway, NJ

2011-03-01

A photosensitive optoelectronic device having an improved hybrid planar bulk heterojunction includes a plurality of photoconductive materials disposed between the anode and the cathode. The photoconductive materials include a first continuous layer of donor material and a second continuous layer of acceptor material. A first network of donor material or materials extends from the first continuous layer toward the second continuous layer, providing continuous pathways for conduction of holes to the first continuous layer. A second network of acceptor material or materials extends from the second continuous layer toward the first continuous layer, providing continuous pathways for conduction of electrons to the second continuous layer. The first network and the second network are interlaced with each other. At least one other photoconductive material is interspersed between the interlaced networks. This other photoconductive material or materials has an absorption spectra different from the donor and acceptor materials.

Organic hybrid planar-nanocrystalline bulk heterojunctions

DOEpatents

Forrest, Stephen R.; Yang, Fan

2013-04-09

A photosensitive optoelectronic device having an improved hybrid planar bulk heterojunction includes a plurality of photoconductive materials disposed between the anode and the cathode. The photoconductive materials include a first continuous layer of donor material and a second continuous layer of acceptor material. A first network of donor material or materials extends from the first continuous layer toward the second continuous layer, providing continuous pathways for conduction of holes to the first continuous layer. A second network of acceptor material or materials extends from the second continuous layer toward the first continuous layer, providing continuous pathways for conduction of electrons to the second continuous layer. The first network and the second network are interlaced with each other. At least one other photoconductive material is interspersed between the interlaced networks. This other photoconductive material or materials has an absorption spectra different from the donor and acceptor materials.

The emergence of asymmetric normal fault systems under symmetric boundary conditions

NASA Astrophysics Data System (ADS)

Schöpfer, Martin P. J.; Childs, Conrad; Manzocchi, Tom; Walsh, John J.; Nicol, Andrew; Grasemann, Bernhard

2017-11-01

Many normal fault systems and, on a smaller scale, fracture boudinage often exhibit asymmetry with one fault dip direction dominating. It is a common belief that the formation of domino and shear band boudinage with a monoclinic symmetry requires a component of layer parallel shearing. Moreover, domains of parallel faults are frequently used to infer the presence of a décollement. Using Distinct Element Method (DEM) modelling we show, that asymmetric fault systems can emerge under symmetric boundary conditions. A statistical analysis of DEM models suggests that the fault dip directions and system polarities can be explained using a random process if the strength contrast between the brittle layer and the surrounding material is high. The models indicate that domino and shear band boudinage are unreliable shear-sense indicators. Moreover, the presence of a décollement should not be inferred on the basis of a domain of parallel faults alone.

Crystallographic structure and superconductive properties of Nb-Ti films with an artificially layered structure

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

Sato, N.

1990-06-15

Artificially layered niobium-titanium (Nb-Ti) films with various thickness ratios (3/1--1/3) and periodicities (2--100 A) are made in an argon or in a mixed argon/nitrogen atmosphere by a dc magnetron sputtering method. Films with small periodicities (less than 30 A) have an artificial superlattice structure (ASL) with crystallographic coherence between constituent layers, where Nb and Ti grow epitaxially on the closest planes. The crystallographic structures of films are bcc with the (110) plane parallel to the film for films with the same or a thicker Nb layer than a Ti layer, and hcp with the (001) plane parallel to the filmmore » for films with a thinner Nb layer than a Ti layer. Films with large periodicities have an artificial superstructure (ASS) with only periodic stacking of constituent layers. Films deposited in the Ar/N atmosphere also have the artificially layered structures of ASL or ASS. The artificially layered structure is thermally stable at temperatures up to 500 {degree}C. The superconducting properties of the films depend strongly on the periodicity and thickness ratio of Nb and Ti layers. The dependence of the transition temperature on the periodicity and thickness ratio is qualitatively explained by a proximity effect with a three-region model. Films with periodicities less than 20 A, composed of the same or a thicker Nb layer than a Ti layer, show high transition temperatures (above 9.3 K). The highest {ital T}{sub {ital c}} of about 13.6 K is obtained in the film composed of monatomic layers of constituents deposited in an Ar atmosphere including 30 vol % N.« less

Advances in understanding of mammalian penile evolution, human penile anatomy and human erection physiology: Clinical implications for physicians and surgeons

PubMed Central

Hsieh, Cheng-Hsing; Liu, Shih-Ping; Hsu, Geng-Long; Chen, Heng-Shuen; Molodysky, Eugen; Chen, Ying-Hui; Yu, Hong-Jeng

2012-01-01

Summary Recent studies substantiate a model of the tunica albuginea of the corpora cavernosa as a bi-layered structure with a 360° complete inner circular layer and a 300° incomplete outer longitudinal coat spanning from the bulbospongiosus and ischiocavernosus proximally and extending continuously into the distal ligament within the glans penis. The anatomical location and histology of the distal ligament invites convincing parallels with the quadrupedal os penis and therefore constitutes potential evidence of the evolutionary process. In the corpora cavernosa, a chamber design is responsible for facilitating rigid erections. For investigating its venous factors exclusively, hemodynamic studies have been performed on both fresh and defrosted human male cadavers. In each case, a rigid erection was unequivocally attainable following venous removal. This clearly has significant ramifications in relation to penile venous surgery and its role in treating impotent patients. One deep dorsal vein, 2 cavernosal veins and 2 pairs of para-arterial veins (as opposed to 1 single vein) are situated between Buck’s fascia and the tunica albuginea. These newfound insights into penile tunical, venous anatomy and erection physiology were inspired by and, in turn, enhance clinical applications routinely encountered by physicians and surgeons, such as penile morphological reconstruction, penile implantation and penile venous surgery. PMID:22739749

Training Deep Convolutional Neural Networks with Resistive Cross-Point Devices

PubMed Central

Gokmen, Tayfun; Onen, Murat; Haensch, Wilfried

2017-01-01

In a previous work we have detailed the requirements for obtaining maximal deep learning performance benefit by implementing fully connected deep neural networks (DNN) in the form of arrays of resistive devices. Here we extend the concept of Resistive Processing Unit (RPU) devices to convolutional neural networks (CNNs). We show how to map the convolutional layers to fully connected RPU arrays such that the parallelism of the hardware can be fully utilized in all three cycles of the backpropagation algorithm. We find that the noise and bound limitations imposed by the analog nature of the computations performed on the arrays significantly affect the training accuracy of the CNNs. Noise and bound management techniques are presented that mitigate these problems without introducing any additional complexity in the analog circuits and that can be addressed by the digital circuits. In addition, we discuss digitally programmable update management and device variability reduction techniques that can be used selectively for some of the layers in a CNN. We show that a combination of all those techniques enables a successful application of the RPU concept for training CNNs. The techniques discussed here are more general and can be applied beyond CNN architectures and therefore enables applicability of the RPU approach to a large class of neural network architectures. PMID:29066942

Training Deep Convolutional Neural Networks with Resistive Cross-Point Devices.

PubMed

Gokmen, Tayfun; Onen, Murat; Haensch, Wilfried

2017-01-01

In a previous work we have detailed the requirements for obtaining maximal deep learning performance benefit by implementing fully connected deep neural networks (DNN) in the form of arrays of resistive devices. Here we extend the concept of Resistive Processing Unit (RPU) devices to convolutional neural networks (CNNs). We show how to map the convolutional layers to fully connected RPU arrays such that the parallelism of the hardware can be fully utilized in all three cycles of the backpropagation algorithm. We find that the noise and bound limitations imposed by the analog nature of the computations performed on the arrays significantly affect the training accuracy of the CNNs. Noise and bound management techniques are presented that mitigate these problems without introducing any additional complexity in the analog circuits and that can be addressed by the digital circuits. In addition, we discuss digitally programmable update management and device variability reduction techniques that can be used selectively for some of the layers in a CNN. We show that a combination of all those techniques enables a successful application of the RPU concept for training CNNs. The techniques discussed here are more general and can be applied beyond CNN architectures and therefore enables applicability of the RPU approach to a large class of neural network architectures.

Methods and results of boundary layer measurements on a glider

NASA Technical Reports Server (NTRS)

Nes, W. V.

1978-01-01

Boundary layer measurements were carried out on a glider under natural conditions. Two effects are investigated: the effect of inconstancy of the development of static pressure within the boundary layer and the effect of the negative pressure difference in a sublaminar boundary layer. The results obtained by means of an ion probe in parallel connection confirm those results obtained by means of a pressure probe. Additional effects which have occurred during these measurements are briefly dealt with.

Spin-valve Josephson junctions for cryogenic memory

NASA Astrophysics Data System (ADS)

Niedzielski, Bethany M.; Bertus, T. J.; Glick, Joseph A.; Loloee, R.; Pratt, W. P.; Birge, Norman O.

2018-01-01

Josephson junctions containing two ferromagnetic layers are being considered for use in cryogenic memory. Our group recently demonstrated that the ground-state phase difference across such a junction with carefully chosen layer thicknesses could be controllably toggled between zero and π by switching the relative magnetization directions of the two layers between the antiparallel and parallel configurations. However, several technological issues must be addressed before those junctions can be used in a large-scale memory. Many of these issues can be more easily studied in single junctions, rather than in the superconducting quantum interference device (SQUID) used for phase-sensitive measurements. In this work, we report a comprehensive study of spin-valve junctions containing a Ni layer with a fixed thickness of 2.0 nm and a NiFe layer of thickness varying between 1.1 and 1.8 nm in steps of 0.1 nm. We extract the field shift of the Fraunhofer patterns and the critical currents of the junctions in the parallel and antiparallel magnetic states, as well as the switching fields of both magnetic layers. We also report a partial study of similar junctions containing a slightly thinner Ni layer of 1.6 nm and the same range of NiFe thicknesses. These results represent the first step toward mapping out a "phase diagram" for phase-controllable spin-valve Josephson junctions as a function of the two magnetic layer thicknesses.

Magnetic field, frequency and temperature dependence of complex conductance of ultrathin La 1.65Sr 0.45CuO 4/La 2CuO 4 films and the organic superconductors κ-(BEDT-TTF) 2Cu[N(CN) 2]Br

DOE PAGES

V. A. Gasparov; Bozovic, I.; He, Xi; ...

2015-09-01

In this study, we used atomic-layer molecular beam epitaxy (ALL-MBE) to synthesize bilayer films of a cuprate metal (La 1.65Sr 0.45CuO 4) and a cuprate insulator (La 2CuO 4), in which interface superconductivity occurs in a layer that is just one-half unit cell thick. We have studied the magnetic field and temperature dependence of the complex sheet conductance, σ(ω), of these films, and compared them to κκ-(BEDT-TTF) 2Cu[N(CN) 2]Br single crystals. The magnetic field H was applied both parallel and perpendicular to the 2D conducting layers. Experiments have been carried out at frequencies between 23 kHz and 50 MHz usingmore » either two-coil mutual inductance technique, or the LC resonators with spiral or rectangular coils. The real and the imaginary parts of the mutual-inductance M(T,ω) between the coil and the sample were measured and converted to complex conductivity. For H perpendicular to the conducting layers, we observed almost identical behavior in both films and κ-Br single crystals: (i) the transition onset in the inductive response, L k –1(T) occurs at a temperature lower by 2 K than in Re σ(T), (ii) this shift is almost constant with magnetic field up to 8 T; (iii) the vortex diffusion constant D(T) is exponential due to pinning of vortex cores. These results can be described by the extended dynamic theory of the Berezinski–Kosterlitz–Thouless (BKT) transition and dynamics of bound vortex–antivortex pairs with short separation lengths.« less

Fabrication and transfer of flexible few-layers MoS2 thin film transistors to any arbitrary substrate.

PubMed

Salvatore, Giovanni A; Münzenrieder, Niko; Barraud, Clément; Petti, Luisa; Zysset, Christoph; Büthe, Lars; Ensslin, Klaus; Tröster, Gerhard

2013-10-22

Recently, transition metal dichalcogenides (TMDCs) have attracted interest thanks to their large field effective mobility (>100 cm(2)/V · s), sizable band gap (around 1-2 eV), and mechanical properties, which make them suitable for high performance and flexible electronics. In this paper, we present a process scheme enabling the fabrication and transfer of few-layers MoS2 thin film transistors from a silicon template to any arbitrary organic or inorganic and flexible or rigid substrate or support. The two-dimensional semiconductor is mechanically exfoliated from a bulk crystal on a silicon/polyvinyl alcohol (PVA)/polymethyl methacrylane (PMMA) stack optimized to ensure high contrast for the identification of subnanometer thick flakes. Thin film transistors (TFTs) with structured source/drain and gate electrodes are fabricated following a designed procedure including steps of UV lithography, wet etching, and atomic layer deposited (ALD) dielectric. Successively, after the dissolution of the PVA sacrificial layer in water, the PMMA film, with the devices on top, can be transferred to another substrate of choice. Here, we transferred the devices on a polyimide plastic foil and studied the performance when tensile strain is applied parallel to the TFT channel. We measured an electron field effective mobility of 19 cm(2)/(V s), an I(on)/I(off)ratio greater than 10(6), a gate leakage current as low as 0.3 pA/μm, and a subthreshold swing of about 250 mV/dec. The devices continue to work when bent to a radius of 5 mm and after 10 consecutive bending cycles. The proposed fabrication strategy can be extended to any kind of 2D materials and enable the realization of electronic circuits and optical devices easily transferrable to any other support.

Terrestrial laser scanning for biomass assessment and tree reconstruction: improved processing efficiency

NASA Astrophysics Data System (ADS)

Alboabidallah, Ahmed; Martin, John; Lavender, Samantha; Abbott, Victor

2017-09-01

Terrestrial Laser Scanning (TLS) processing for biomass mapping involves large data volumes, and often includes relatively slow 3D object fitting steps that increase the processing time. This study aimed to test new features that can speed up the overall processing time. A new type of 3D voxel is used, where the horizontal layers are parallel to the Digital Terrain Model. This voxel type allows procedures to extract tree diameters using just one layer, but still gives direct tree-height estimations. Layer intersection is used to emphasize the trunks as upright standing objects, which are detected in the spatially segmented intersection of the breast-height voxels and then extended upwards and downwards. The diameters were calculated by fitting elliptical cylinders to the laser points in the detected trunk segments. Non-trunk segments, used in sub-tree- structures, were found using the parent-child relationships between successive layers. The branches were reconstructed by skeletonizing each sub-tree branch, and the biomass was distributed statistically amongst the weighted skeletons. The procedure was applied to nine plots within the UK. The average correlation coefficients between reconstructed and directly measured tree diameters, heights and branches were R2 = 0.92, 0.97 and 0.59 compared to 0.91, 0.95, and 0.63 when cylindrical fitting was used. The average time to apply the method reduced from 5hrs:18mins per plot, for the conventional methods, to 2hrs:24mins when the same hardware and software libraries were used with the 3D voxels. These results indicate that this 3D voxel method can produce, much more quickly, results of a similar accuracy that would improve efficiency if applied to projects with large volume TLS datasets.

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

Agosta, C. C.; Jin, J.; Coniglio, W. A.

We present upper critical field data for {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2} with the magnetic field close to parallel and parallel to the conducting layers. We show that we can eliminate the effect of vortex dynamics in these layered materials if the layers are oriented within 0.3-inch of parallel to the applied magnetic field. Eliminating vortex effects leaves one remaining feature in the data that corresponds to the Pauli paramagnetic limit (H{sub p}). We propose a semiempirical method to calculate the H{sub p} in quasi-2D superconductors. This method takes into account the energy gap of each of the quasi-2D superconductors, which ismore » calculated from specific-heat data, and the influence of many-body effects. The calculated Pauli paramagnetic limits are then compared to critical field data for the title compound and other organic conductors. Many of the examined quasi-2D superconductors, including the above organic superconductors and CeCoIn{sub 5}, exhibit upper critical fields that exceed their calculated H{sub p} suggesting unconventional superconductivity. We show that the high-field low-temperature state in {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2} is consistent with the Fulde-Ferrell-Larkin-Ovchinnikov state.« less

Soft lubrication: The elastohydrodynamics of nonconforming and conforming contacts

NASA Astrophysics Data System (ADS)

Skotheim, J. M.; Mahadevan, L.

2005-09-01

We study the lubrication of fluid-immersed soft interfaces and show that elastic deformation couples tangential and normal forces and thus generates lift. We consider materials that deform easily, due to either geometry (e.g., a shell) or constitutive properties (e.g., a gel or a rubber), so that the effects of pressure and temperature on the fluid properties may be neglected. Four different system geometries are considered: a rigid cylinder moving parallel to a soft layer coating a rigid substrate; a soft cylinder moving parallel to a rigid substrate; a cylindrical shell moving parallel to a rigid substrate; and finally a cylindrical conforming journal bearing coated with a thin soft layer. In addition, for the particular case of a soft layer coating a rigid substrate, we consider both elastic and poroelastic material responses. For all these cases, we find the same generic behavior: there is an optimal combination of geometric and material parameters that maximizes the dimensionless normal force as a function of the softness parameter η =hydrodynamicpressure/elasticstiffness=surfacedeflection/gapthickness, which characterizes the fluid-induced deformation of the interface. The corresponding cases for a spherical slider are treated using scaling concepts.

Interdisciplinary Science through the Parallel Curriculum Model: Lessons from the Sea

ERIC Educational Resources Information Center

Hathcock, Stephanie J.

2018-01-01

The Parallel Curriculum Model (PCM) lends itself to considering curriculum development from different angles. It begins with a solid Core Curriculum and can then be extended through the Curriculum of Connections, Practice, and Identity. This article showcases a way of thinking about the creation of a PCM unit by providing examples from an…

The salinity effect in a mixed layer ocean model

NASA Technical Reports Server (NTRS)

Miller, J. R.

1976-01-01

A model of the thermally mixed layer in the upper ocean as developed by Kraus and Turner and extended by Denman is further extended to investigate the effects of salinity. In the tropical and subtropical Atlantic Ocean rapid increases in salinity occur at the bottom of a uniformly mixed surface layer. The most significant effects produced by the inclusion of salinity are the reduction of the deepening rate and the corresponding change in the heating characteristics of the mixed layer. If the net surface heating is positive, but small, salinity effects must be included to determine whether the mixed layer temperature will increase or decrease. Precipitation over tropical oceans leads to the development of a shallow stable layer accompanied by a decrease in the temperature and salinity at the sea surface.

Parallel electric fields in extragalactic jets - Double layers and anomalous resistivity in symbiotic relationships

NASA Technical Reports Server (NTRS)

Borovsky, J. E.

1986-01-01

After examining the properties of Coulomb-collision resistivity, anomalous (collective) resistivity, and double layers, a hybrid anomalous-resistivity/double-layer model is introduced. In this model, beam-driven waves on both sides of a double layer provide electrostatic plasma-wave turbulence that greatly reduces the mobility of charged particles. These regions then act to hold open a density cavity within which the double layer resides. In the double layer, electrical energy is dissipated with 100 percent efficiency into high-energy particles, creating conditions optimal for the collective emission of polarized radio waves.

Solar panel truss mounting systems and methods

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

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the basemore » rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.« less

Performance evaluation of parallel electric field tunnel field-effect transistor by a distributed-element circuit model

NASA Astrophysics Data System (ADS)

Morita, Yukinori; Mori, Takahiro; Migita, Shinji; Mizubayashi, Wataru; Tanabe, Akihito; Fukuda, Koichi; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shin-ichi; Liu, Yongxun; Masahara, Meishoku; Ota, Hiroyuki

2014-12-01

The performance of parallel electric field tunnel field-effect transistors (TFETs), in which band-to-band tunneling (BTBT) was initiated in-line to the gate electric field was evaluated. The TFET was fabricated by inserting an epitaxially-grown parallel-plate tunnel capacitor between heavily doped source wells and gate insulators. Analysis using a distributed-element circuit model indicated there should be a limit of the drain current caused by the self-voltage-drop effect in the ultrathin channel layer.

Analysis of Lagrangian stretching in turbulent channel flow using a database task-parallel particle tracking approach

NASA Astrophysics Data System (ADS)

Meneveau, Charles; Johnson, Perry; Hamilton, Stephen; Burns, Randal

2016-11-01

An intrinsic property of turbulent flows is the exponential deformation of fluid elements along Lagrangian paths. The production of enstrophy by vorticity stretching follows from a similar mechanism in the Lagrangian view, though the alignment statistics differ and viscosity prevents unbounded growth. In this paper, the stretching properties of fluid elements and vorticity along Lagrangian paths are studied in a channel flow at Reτ = 1000 and compared with prior, known results from isotropic turbulence. To track Lagrangian paths in a public database containing Direct Numerical Simulation (DNS) results, the task-parallel approach previously employed in the isotropic database is extended to the case of flow in a bounded domain. It is shown that above 100 viscous units from the wall, stretching statistics are equal to their isotropic values, in support of the local isotropy hypothesis. Normalized by dissipation rate, the stretching in the buffer layer and below is less efficient due to less favorable alignment statistics. The Cramér function characterizing cumulative Lagrangian stretching statistics shows that overall the channel flow has about half of the stretching per unit dissipation compared with isotropic turbulence. Supported by a National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1232825, and by National Science Foundation Grants CBET-1507469, ACI-1261715, OCI-1244820 and by JHU IDIES.

Autoclave processing for composite material fabrication. 1: An analysis of resin flows and fiber compactions for thin laminate

NASA Technical Reports Server (NTRS)

Hou, T. H.

1985-01-01

High quality long fiber reinforced composites, such as those used in aerospace and industrial applications, are commonly processed in autoclaves. An adequate resin flow model for the entire system (laminate/bleeder/breather), which provides a description of the time-dependent laminate consolidation process, is useful in predicting the loss of resin, heat transfer characteristics, fiber volume fraction and part dimension, etc., under a specified set of processing conditions. This could be accomplished by properly analyzing the flow patterns and pressure profiles inside the laminate during processing. A newly formulated resin flow model for composite prepreg lamination process is reported. This model considers viscous resin flows in both directions perpendicular and parallel to the composite plane. In the horizontal direction, a squeezing flow between two nonporous parallel plates is analyzed, while in the vertical direction, a poiseuille type pressure flow through porous media is assumed. Proper force and mass balances have been made and solved for the whole system. The effects of fiber-fiber interactions during lamination are included as well. The unique features of this analysis are: (1) the pressure gradient inside the laminate is assumed to be generated from squeezing action between two adjacent approaching fiber layers, and (2) the behavior of fiber bundles is simulated by a Finitely Extendable Nonlinear Elastic (FENE) spring.

Wheel-type magnetic refrigerator

DOEpatents

Barclay, John A.

1983-01-01

The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load.

Wheel-type magnetic refrigerator

DOEpatents

Barclay, J.A.

1982-01-20

The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load.

The Properties of HPMC:PEO Extended Release Hydrophilic Matrices and their Response to Ionic Environments.

PubMed

Hu, Anran; Chen, Chen; Mantle, Michael D; Wolf, Bettina; Gladden, Lynn F; Rajabi-Siahboomi, Ali; Missaghi, Shahrzad; Mason, Laura; Melia, Colin D

2017-05-01

Investigate the extended release behaviour of compacts containing mixtures of hydrophilic HPMC and PEO in hydrating media of differing ionic strengths. The extended release behaviour of various HPMC:PEO compacts was investigated using dissolution testing, confocal microscopy and magnetic resonance imaging, with respect to polymer ratio and ionic strength of the hydrating media. Increasing HPMC content gave longer extended release times, but a greater sensitivity to high ionic dissolution environments. Increasing PEO content reduced this sensitivity. The addition of PEO to a predominantly HPMC matrix reduced release rate sensitivity to high ionic environments. Confocal microscopy of early gel layer development showed the two polymers appeared to contribute independently to gel layer structure whilst together forming a coherent and effective diffusion barrier. There was some evidence that poorly swollen HPMC particles added a tortuosity barrier to the gel layer in high ionic strength environments, resulting in prolonged extended release. MRI provides unique, non-invasive spatially resolved information from within the HPMC:PEO compacts that furthers our understanding of USP 1 and USP 4 dissolution data. Confocal microscopy and MRI data show that combinations of HPMC and PEO have advantageous extended release properties, in comparison with matrices containing a single polymer.

Detection of Multi-Layer and Vertically-Extended Clouds Using A-Train Sensors

NASA Technical Reports Server (NTRS)

Joiner, J.; Vasilkov, A. P.; Bhartia, P. K.; Wind, G.; Platnick, S.; Menzel, W. P.

2010-01-01

The detection of mUltiple cloud layers using satellite observations is important for retrieval algorithms as well as climate applications. In this paper, we describe a relatively simple algorithm to detect multiple cloud layers and distinguish them from vertically-extended clouds. The algorithm can be applied to coincident passive sensors that derive both cloud-top pressure from the thermal infrared observations and an estimate of solar photon pathlength from UV, visible, or near-IR measurements. Here, we use data from the A-train afternoon constellation of satellites: cloud-top pressure, cloud optical thickness, the multi-layer flag from the Aqua MODerate-resolution Imaging Spectroradiometer (MODIS) and the optical centroid cloud pressure from the Aura Ozone Monitoring Instrument (OMI). For the first time, we use data from the CloudSat radar to evaluate the results of a multi-layer cloud detection scheme. The cloud classification algorithms applied with different passive sensor configurations compare well with each other as well as with data from CloudSat. We compute monthly mean fractions of pixels containing multi-layer and vertically-extended clouds for January and July 2007 at the OMI spatial resolution (l2kmx24km at nadir) and at the 5kmx5km MODIS resolution used for infrared cloud retrievals. There are seasonal variations in the spatial distribution of the different cloud types. The fraction of cloudy pixels containing distinct multi-layer cloud is a strong function of the pixel size. Globally averaged, these fractions are approximately 20% and 10% for OMI and MODIS, respectively. These fractions may be significantly higher or lower depending upon location. There is a much smaller resolution dependence for fractions of pixels containing vertically-extended clouds (approx.20% for OMI and slightly less for MODIS globally), suggesting larger spatial scales for these clouds. We also find higher fractions of vertically-extended clouds over land as compared with ocean, particularly in the tropics and summer hemisphere.

Reaction rates of graphite with ozone measured by etch decoration

NASA Technical Reports Server (NTRS)

Hennig, G. R.; Montet, G. L.

1968-01-01

Etch-decoration technique of detecting vacancies in graphite has been used to determine the reaction rates of graphite with ozone in the directions parallel and perpendicular to the layer planes. It consists essentially of peeling single atom layers off graphite crystals without affecting the remainder of the crystal.

Statistical crossover characterization of the heterotic localized-extended transition.

PubMed

Ugajin, Ryuichi

2003-07-01

We investigated the spectral statistics of a quantum particle in a superlattice consisting of a disordered layer and a clean layer, possibly accompanied by random magnetic fields. Because a disordered layer has localized states and a clean layer has extended states, our quantum system shows a heterotic phase of an Anderson insulator and a normal metal. As the ratio of the volume of these two layers changes, the spectral statistics change from Poissonian to one of the Gaussian ensembles which characterize quantum chaos. A crossover distribution specified by two parameters is introduced to distinguish the transition from an integrable system to a quantum chaotic system during the heterotic phase from an Anderson transition in which the degree of random potentials is homogenous.

Anatomical relationships of the procerus with the nasal ala and the nasal muscles: transverse part of the nasalis and levator labii superioris alaeque nasi.

PubMed

Hur, Mi-Sun

2017-08-01

The aim of this study was to clarify the anatomical relationship of the procerus with the nose, especially focusing on the transverse part of the nasalis, the nasal ala, and the levator labii superioris alaeque nasi (LLSAN). The 53 faces from Korean cadavers were examined anatomically. The procerus originated from the superficial and deep layers in all specimens. Some fibers of the lateral part of the superficial layer extended to connect to the transverse part of the nasalis, while other such fibers extended to attach to the skin of the upper nasal ala in all specimens. The superficial and deep layers of the procerus merged and then intermingled with the frontalis. The anatomical relationship between the superficial layer of the procerus and the LLSAN was classified into the following two categories according to their connections. Some medial originating fibers of the LLSAN extended superomedially to blend in the area between the superficial layer of the procerus and the depressor supercilii (13.5%). And, some medial originating fibers of the LLSAN extended superomedially and then constituted the lateral portion of the superficial layer of the procerus (7.7%). This study has yielded crucial data for understanding the anatomical relationships and functions of the procerus in relation to the nose. They will be helpful when designing effective therapies involving botulinum toxin type A, performing various types of rhinoplasty and facial surgeries, and in electromyography analyses.

Efficacy and Safety of Dexmethylphenidate Extended-Release Capsules in Children with Attention-Deficit/Hyperactivity Disorder

ERIC Educational Resources Information Center

Greenhill, Laurence L.; Muniz, Rafael; Ball, Roberta R.; Levine, Alan; Pestreich, Linda; Jiang, Hai

2006-01-01

Objective: The efficacy and safety of dexmethylphenidate extended release (d-MPH-ER) was compared to placebo in pediatric patients with attention-deficit/hyperactivity disorder (ADHD). Method: This multicenter, randomized, double-blind, placebo-controlled, parallel-group, two-phase study included 97 patients (ages 6-17 years) with…

CMUTs with high-K atomic layer deposition dielectric material insulation layer.

PubMed

Xu, Toby; Tekes, Coskun; Degertekin, F

2014-12-01

Use of high-κ dielectric, atomic layer deposition (ALD) materials as an insulation layer material for capacitive micromachined ultrasonic transducers (CMUTs) is investigated. The effect of insulation layer material and thickness on CMUT performance is evaluated using a simple parallel plate model. The model shows that both high dielectric constant and the electrical breakdown strength are important for the dielectric material, and significant performance improvement can be achieved, especially as the vacuum gap thickness is reduced. In particular, ALD hafnium oxide (HfO2) is evaluated and used as an improvement over plasma-enhanced chemical vapor deposition (PECVD) silicon nitride (Six)Ny)) for CMUTs fabricated by a low-temperature, complementary metal oxide semiconductor transistor-compatible, sacrificial release method. Relevant properties of ALD HfO2) such as dielectric constant and breakdown strength are characterized to further guide CMUT design. Experiments are performed on parallel fabricated test CMUTs with 50-nm gap and 16.5-MHz center frequency to measure and compare pressure output and receive sensitivity for 200-nm PECVD Six)Ny) and 100-nm HfO2) insulation layers. Results for this particular design show a 6-dB improvement in receiver output with the collapse voltage reduced by one-half; while in transmit mode, half the input voltage is needed to achieve the same maximum output pressure.

Linear and nonlinear stability of the Blasius boundary layer

NASA Technical Reports Server (NTRS)

Bertolotti, F. P.; Herbert, TH.; Spalart, P. R.

1992-01-01

Two new techniques for the study of the linear and nonlinear instability in growing boundary layers are presented. The first technique employs partial differential equations of parabolic type exploiting the slow change of the mean flow, disturbance velocity profiles, wavelengths, and growth rates in the streamwise direction. The second technique solves the Navier-Stokes equation for spatially evolving disturbances using buffer zones adjacent to the inflow and outflow boundaries. Results of both techniques are in excellent agreement. The linear and nonlinear development of Tollmien-Schlichting (TS) waves in the Blasius boundary layer is investigated with both techniques and with a local procedure based on a system of ordinary differential equations. The results are compared with previous work and the effects of non-parallelism and nonlinearity are clarified. The effect of nonparallelism is confirmed to be weak and, consequently, not responsible for the discrepancies between measurements and theoretical results for parallel flow.

HADY-I, a FORTRAN program for the compressible stability analysis of three-dimensional boundary layers. [on swept and tapered wings

NASA Technical Reports Server (NTRS)

El-Hady, N. M.

1981-01-01

A computer program HADY-I for calculating the linear incompressible or compressible stability characteristics of the laminar boundary layer on swept and tapered wings is described. The eigenvalue problem and its adjoint arising from the linearized disturbance equations with the appropriate boundary conditions are solved numerically using a combination of Newton-Raphson interative scheme and a variable step size integrator based on the Runge-Kutta-Fehlburh fifth-order formulas. The integrator is used in conjunction with a modified Gram-Schmidt orthonormalization procedure. The computer program HADY-I calculates the growth rates of crossflow or streamwise Tollmien-Schlichting instabilities. It also calculates the group velocities of these disturbances. It is restricted to parallel stability calculations, where the boundary layer (meanflow) is assumed to be parallel. The meanflow solution is an input to the program.

Ordering transitions of weakly anisotropic hard rods in narrow slitlike pores.

PubMed

Aliabadi, Roohollah; Gurin, Péter; Velasco, Enrique; Varga, Szabolcs

2018-01-01

The effect of strong confinement on the positional and orientational ordering is examined in a system of hard rectangular rods with length L and diameter D (L>D) using the Parsons-Lee modification of the second virial density-functional theory. The rods are nonmesogenic (L/D<3) and confined between two parallel hard walls, where the width of the pore (H) is chosen in such a way that both planar (particle's long axis parallel to the walls) and homeotropic (particle's long axis perpendicular to the walls) orderings are possible and a maximum of two layers is allowed to form in the pore. In the extreme confinement limit of H≤2D, where only one-layer structures appear, we observe a structural transition from a planar to a homeotropic fluid layer with increasing density, which becomes sharper as L→H. In wider pores (2D

Keldysh formalism for multiple parallel worlds

NASA Astrophysics Data System (ADS)

Ansari, M.; Nazarov, Y. V.

2016-03-01

We present a compact and self-contained review of the recently developed Keldysh formalism for multiple parallel worlds. The formalism has been applied to consistent quantum evaluation of the flows of informational quantities, in particular, to the evaluation of Renyi and Shannon entropy flows. We start with the formulation of the standard and extended Keldysh techniques in a single world in a form convenient for our presentation. We explain the use of Keldysh contours encompassing multiple parallel worlds. In the end, we briefly summarize the concrete results obtained with the method.

Method and apparatus for fabrication of high gradient insulators with parallel surface conductors spaced less than one millimeter apart

DOEpatents

Sanders, David M.; Decker, Derek E.

1999-01-01

Optical patterns and lithographic techniques are used as part of a process to embed parallel and evenly spaced conductors in the non-planar surfaces of an insulator to produce high gradient insulators. The approach extends the size that high gradient insulating structures can be fabricated as well as improves the performance of those insulators by reducing the scale of the alternating parallel lines of insulator and conductor along the surface. This fabrication approach also substantially decreases the cost required to produce high gradient insulators.

Keldysh formalism for multiple parallel worlds

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

Ansari, M.; Nazarov, Y. V., E-mail: y.v.nazarov@tudelft.nl

We present a compact and self-contained review of the recently developed Keldysh formalism for multiple parallel worlds. The formalism has been applied to consistent quantum evaluation of the flows of informational quantities, in particular, to the evaluation of Renyi and Shannon entropy flows. We start with the formulation of the standard and extended Keldysh techniques in a single world in a form convenient for our presentation. We explain the use of Keldysh contours encompassing multiple parallel worlds. In the end, we briefly summarize the concrete results obtained with the method.

Porting LAMMPS to GPUs.

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

Brown, William Michael; Plimpton, Steven James; Wang, Peng

2010-03-01

LAMMPS is a classical molecular dynamics code, and an acronym for Large-scale Atomic/Molecular Massively Parallel Simulator. LAMMPS has potentials for soft materials (biomolecules, polymers) and solid-state materials (metals, semiconductors) and coarse-grained or mesoscopic systems. It can be used to model atoms or, more generically, as a parallel particle simulator at the atomic, meso, or continuum scale. LAMMPS runs on single processors or in parallel using message-passing techniques and a spatial-decomposition of the simulation domain. The code is designed to be easy to modify or extend with new functionality.

Clustering on Magnesium Surfaces - Formation and Diffusion Energies.

PubMed

Chu, Haijian; Huang, Hanchen; Wang, Jian

2017-07-12

The formation and diffusion energies of atomic clusters on Mg surfaces determine the surface roughness and formation of faulted structure, which in turn affect the mechanical deformation of Mg. This paper reports first principles density function theory (DFT) based quantum mechanics calculation results of atomic clustering on the low energy surfaces {0001} and [Formula: see text]. In parallel, molecular statics calculations serve to test the validity of two interatomic potentials and to extend the scope of the DFT studies. On a {0001} surface, a compact cluster consisting of few than three atoms energetically prefers a face-centered-cubic stacking, to serve as a nucleus of stacking fault. On a [Formula: see text], clusters of any size always prefer hexagonal-close-packed stacking. Adatom diffusion on surface [Formula: see text] is high anisotropic while isotropic on surface (0001). Three-dimensional Ehrlich-Schwoebel barriers converge as the step height is three atomic layers or thicker. Adatom diffusion along steps is via hopping mechanism, and that down steps is via exchange mechanism.

Large-scale self-assembled zirconium phosphate smectic layers via a simple spray-coating process

NASA Astrophysics Data System (ADS)

Wong, Minhao; Ishige, Ryohei; White, Kevin L.; Li, Peng; Kim, Daehak; Krishnamoorti, Ramanan; Gunther, Robert; Higuchi, Takeshi; Jinnai, Hiroshi; Takahara, Atsushi; Nishimura, Riichi; Sue, Hung-Jue

2014-04-01

The large-scale assembly of asymmetric colloidal particles is used in creating high-performance fibres. A similar concept is extended to the manufacturing of thin films of self-assembled two-dimensional crystal-type materials with enhanced and tunable properties. Here we present a spray-coating method to manufacture thin, flexible and transparent epoxy films containing zirconium phosphate nanoplatelets self-assembled into a lamellar arrangement aligned parallel to the substrate. The self-assembled mesophase of zirconium phosphate nanoplatelets is stabilized by epoxy pre-polymer and exhibits rheology favourable towards large-scale manufacturing. The thermally cured film forms a mechanically robust coating and shows excellent gas barrier properties at both low- and high humidity levels as a result of the highly aligned and overlapping arrangement of nanoplatelets. This work shows that the large-scale ordering of high aspect ratio nanoplatelets is easier to achieve than previously thought and may have implications in the technological applications for similar materials.

(Di­methyl­phosphor­yl)methanaminium hydrogen oxalate–oxalic acid (2/1)

PubMed Central

Bialek, Sebastian; Clemens, Rebecca; Reiss, Guido J.

2014-01-01

The reaction of (di­methyl­phosphor­yl)methanamine (dpma) with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4 −·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-mol­ecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16°) whereas the oxalic acid molecule shows a significantly smaller bend angle (∼7°). In the crystal, the components are connected by strong O—H⋯O and much weaker N—H⋯O hydrogen bonds, leading to the formation of layers extending parallel to (001). The structure was refined from a racemically twinned crystal with twin components in an approximate 1:1 ratio. PMID:24765013

Mechanical properties of electrospun bilayer fibrous membranes as potential scaffolds for tissue engineering.

PubMed

Pu, Juan; Komvopoulos, Kyriakos

2014-06-01

Bilayer fibrous membranes of poly(l-lactic acid) (PLLA) were fabricated by electrospinning, using a parallel-disk mandrel configuration that resulted in the sequential deposition of a layer with fibers aligned across the two parallel disks and a layer with randomly oriented fibers, both layers deposited in a single process step. Membrane structure and fiber alignment were characterized by scanning electron microscopy and two-dimensional fast Fourier transform. Because of the intricacies of the generated electric field, bilayer membranes exhibited higher porosity than single-layer membranes consisting of randomly oriented fibers fabricated with a solid-drum collector. However, despite their higher porosity, bilayer membranes demonstrated generally higher elastic modulus, yield strength and toughness than single-layer membranes with random fibers. Bilayer membrane deformation at relatively high strain rates comprised multiple abrupt microfracture events characterized by discontinuous fiber breakage. Bilayer membrane elongation yielded excessive necking of the layer with random fibers and remarkable fiber stretching (on the order of 400%) in the layer with fibers aligned in the stress direction. In addition, fibers in both layers exhibited multiple localized necking, attributed to the nonuniform distribution of crystalline phases in the fibrillar structure. The high membrane porosity, good mechanical properties, and good biocompatibility and biodegradability of PLLA (demonstrated in previous studies) make the present bilayer membranes good scaffold candidates for a wide range of tissue engineering applications. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Cellular automata with object-oriented features for parallel molecular network modeling.

PubMed

Zhu, Hao; Wu, Yinghui; Huang, Sui; Sun, Yan; Dhar, Pawan

2005-06-01

Cellular automata are an important modeling paradigm for studying the dynamics of large, parallel systems composed of multiple, interacting components. However, to model biological systems, cellular automata need to be extended beyond the large-scale parallelism and intensive communication in order to capture two fundamental properties characteristic of complex biological systems: hierarchy and heterogeneity. This paper proposes extensions to a cellular automata language, Cellang, to meet this purpose. The extended language, with object-oriented features, can be used to describe the structure and activity of parallel molecular networks within cells. Capabilities of this new programming language include object structure to define molecular programs within a cell, floating-point data type and mathematical functions to perform quantitative computation, message passing capability to describe molecular interactions, as well as new operators, statements, and built-in functions. We discuss relevant programming issues of these features, including the object-oriented description of molecular interactions with molecule encapsulation, message passing, and the description of heterogeneity and anisotropy at the cell and molecule levels. By enabling the integration of modeling at the molecular level with system behavior at cell, tissue, organ, or even organism levels, the program will help improve our understanding of how complex and dynamic biological activities are generated and controlled by parallel functioning of molecular networks. Index Terms-Cellular automata, modeling, molecular network, object-oriented.

Magnetosheath Filamentary Structures Formed by Ion Acceleration at the Quasi-Parallel Bow Shock

NASA Technical Reports Server (NTRS)

Omidi, N.; Sibeck, D.; Gutynska, O.; Trattner, K. J.

2014-01-01

Results from 2.5-D electromagnetic hybrid simulations show the formation of field-aligned, filamentary plasma structures in the magnetosheath. They begin at the quasi-parallel bow shock and extend far into the magnetosheath. These structures exhibit anticorrelated, spatial oscillations in plasma density and ion temperature. Closer to the bow shock, magnetic field variations associated with density and temperature oscillations may also be present. Magnetosheath filamentary structures (MFS) form primarily in the quasi-parallel sheath; however, they may extend to the quasi-perpendicular magnetosheath. They occur over a wide range of solar wind Alfvénic Mach numbers and interplanetary magnetic field directions. At lower Mach numbers with lower levels of magnetosheath turbulence, MFS remain highly coherent over large distances. At higher Mach numbers, magnetosheath turbulence decreases the level of coherence. Magnetosheath filamentary structures result from localized ion acceleration at the quasi-parallel bow shock and the injection of energetic ions into the magnetosheath. The localized nature of ion acceleration is tied to the generation of fast magnetosonic waves at and upstream of the quasi-parallel shock. The increased pressure in flux tubes containing the shock accelerated ions results in the depletion of the thermal plasma in these flux tubes and the enhancement of density in flux tubes void of energetic ions. This results in the observed anticorrelation between ion temperature and plasma density.

Inland fields of dispersed cobbles and boulders as evidence for a tsunami on Anegada, British Virgin Islands

USGS Publications Warehouse

Jaffe, Bruce E.; Watt, Steve; Buckley, Mark

2012-01-01

Marine overwash from the north a few centuries ago transported hundreds of angular cobbles and boulders tens to hundreds of meters southward from limestone outcrops in the interior of Anegada, 140 km east–northeast of Puerto Rico. We examined two of several cobble and boulder fields as part of an effort to interpret whether the overwash resulted from a tsunami or a storm in a location where both events are known to occur. One of the cobble and boulder field extends 200 m southward from limestone outcrops that are 300 m inland from the island’s north shore. The other field extends 100 m southward from a limestone knoll located 800 m from the nearest shore. In the two fields, we measured the size, orientation, and spatial distribution of a total of 161 clasts and determined their stratigraphic positions with respect to an overwash sand and shell sheet deposit. In both fields, we found the spacing between clasts increased southward and that clast long-axis orientations are consistent with a transport trending north–south. Almost half the clasts are partially buried in a landward thinning and fining overwash sand and none were found embedded in the shelly mud of a pre-overwash marine pond. The two cobble and boulder fields resemble modern tsunami deposits in which dispersed clasts extend inland as a single layer. The fields contrast with coarse clast storm deposits that often form wedge-shaped shore-parallel ridges. These comparisons suggest that the overwash resulted from a tsunami and not from a storm.

The Influence of the Hall Term on the Development of Magnetized Laser-Produced Plasma Jets

DOE PAGES

Hamlin, N.D.; Seyler, C. E.; Khiar, B.

2018-04-29

We present 2D axisymmetric simulation results describing the influence of the Hall term on laser-produced plasma jets and their interaction with an applied magnetic field parallel to the laser axis. Bending of the poloidal B-field lines produces an MHD shock structure surrounding a conical cavity, and a jet is produced from the convergence of the shock envelope. Both the jet and the conical cavity underneath it are bound by fast MHD shocks. We compare the MHD results generated using the extended-MHD code Physics as an Extended-MHD Relaxation System with an Efficient Upwind Scheme (PERSEUS) with MHD results generated using GORGONmore » and find reasonable agreement. We then present extended-MHD results generated using PERSEUS, which show that the Hall term has several effects on the plasma jet evolution. A hot low-density current-carrying layer of plasma develops just outside the plume, which results in a helical rather than a purely poloidal B-field, and reduces magnetic stresses, resulting in delayed flow convergence and jet formation. The flow is partially frozen into the helical field, resulting in azimuthal rotation of the jet. The Hall term also produces field-aligned current in strongly magnetized regions. In particular, we find the influence of Hall physics on this problem to be scale-dependent. In conclusion, this points to the importance of mitigating the Hall effect in a laboratory setup, by increasing the jet density and system dimensions, in order to avoid inaccurate extrapolation to astrophysical scales.« less

The Influence of the Hall Term on the Development of Magnetized Laser-Produced Plasma Jets

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

Hamlin, N.D.; Seyler, C. E.; Khiar, B.

We present 2D axisymmetric simulation results describing the influence of the Hall term on laser-produced plasma jets and their interaction with an applied magnetic field parallel to the laser axis. Bending of the poloidal B-field lines produces an MHD shock structure surrounding a conical cavity, and a jet is produced from the convergence of the shock envelope. Both the jet and the conical cavity underneath it are bound by fast MHD shocks. We compare the MHD results generated using the extended-MHD code Physics as an Extended-MHD Relaxation System with an Efficient Upwind Scheme (PERSEUS) with MHD results generated using GORGONmore » and find reasonable agreement. We then present extended-MHD results generated using PERSEUS, which show that the Hall term has several effects on the plasma jet evolution. A hot low-density current-carrying layer of plasma develops just outside the plume, which results in a helical rather than a purely poloidal B-field, and reduces magnetic stresses, resulting in delayed flow convergence and jet formation. The flow is partially frozen into the helical field, resulting in azimuthal rotation of the jet. The Hall term also produces field-aligned current in strongly magnetized regions. In particular, we find the influence of Hall physics on this problem to be scale-dependent. In conclusion, this points to the importance of mitigating the Hall effect in a laboratory setup, by increasing the jet density and system dimensions, in order to avoid inaccurate extrapolation to astrophysical scales.« less

Exact coherent structures in an asymptotically reduced description of parallel shear flows

NASA Astrophysics Data System (ADS)

Beaume, Cédric; Knobloch, Edgar; Chini, Gregory P.; Julien, Keith

2015-02-01

A reduced description of shear flows motivated by the Reynolds number scaling of lower-branch exact coherent states in plane Couette flow (Wang J, Gibson J and Waleffe F 2007 Phys. Rev. Lett. 98 204501) is constructed. Exact time-independent nonlinear solutions of the reduced equations corresponding to both lower and upper branch states are found for a sinusoidal, body-forced shear flow. The lower branch solution is characterized by fluctuations that vary slowly along the critical layer while the upper branch solutions display a bimodal structure and are more strongly focused on the critical layer. The reduced equations provide a rational framework for investigations of subcritical spatiotemporal patterns in parallel shear flows.

Stability investigations of airfoil flow by global analysis

NASA Technical Reports Server (NTRS)

Morzynski, Marek; Thiele, Frank

1992-01-01

As the result of global, non-parallel flow stability analysis the single value of the disturbance growth-rate and respective frequency is obtained. This complex value characterizes the stability of the whole flow configuration and is not referred to any particular flow pattern. The global analysis assures that all the flow elements (wake, boundary and shear layer) are taken into account. The physical phenomena connected with the wake instability are properly reproduced by the global analysis. This enhances the investigations of instability of any 2-D flows, including ones in which the boundary layer instability effects are known to be of dominating importance. Assuming fully 2-D disturbance form, the global linear stability problem is formulated. The system of partial differential equations is solved for the eigenvalues and eigenvectors. The equations, written in the pure stream function formulation, are discretized via FDM using a curvilinear coordinate system. The complex eigenvalues and corresponding eigenvectors are evaluated by an iterative method. The investigations performed for various Reynolds numbers emphasize that the wake instability develops into the Karman vortex street. This phenomenon is shown to be connected with the first mode obtained from the non-parallel flow stability analysis. The higher modes are reflecting different physical phenomena as for example Tollmien-Schlichting waves, originating in the boundary layer and having the tendency to emerge as instabilities for the growing Reynolds number. The investigations are carried out for a circular cylinder, oblong ellipsis and airfoil. It is shown that the onset of the wake instability, the waves in the boundary layer, the shear layer instability are different solutions of the same eigenvalue problem, formulated using the non-parallel theory. The analysis offers large potential possibilities as the generalization of methods used till now for the stability analysis.

One-dimensional models of quasi-neutral parallel electric fields

NASA Technical Reports Server (NTRS)

Stern, D. P.

1981-01-01

Parallel electric fields can exist in the magnetic mirror geometry of auroral field lines if they conform to the quasineutral equilibrium solutions. Results on quasi-neutral equilibria and on double layer discontinuities were reviewed and the effects on such equilibria due to non-unique solutions, potential barriers and field aligned current flows using as inputs monoenergetic isotropic distribution functions were examined.

Reconstruction of 3D Shapes of Opaque Cumulus Clouds from Airborne Multiangle Imaging: A Proof-of-Concept

NASA Astrophysics Data System (ADS)

Davis, A. B.; Bal, G.; Chen, J.

2015-12-01

Operational remote sensing of microphysical and optical cloud properties is invariably predicated on the assumption of plane-parallel slab geometry for the targeted cloud. The sole benefit of this often-questionable assumption about the cloud is that it leads to one-dimensional (1D) radiative transfer (RT)---a textbook, computationally tractable model. We present new results as evidence that, thanks to converging advances in 3D RT, inverse problem theory, algorithm implementation, and computer hardware, we are at the dawn of a new era in cloud remote sensing where we can finally go beyond the plane-parallel paradigm. Granted, the plane-parallel/1D RT assumption is reasonable for spatially extended stratiform cloud layers, as well as the smoothly distributed background aerosol layers. However, these 1D RT-friendly scenarios exclude cases that are critically important for climate physics. 1D RT---whence operational cloud remote sensing---fails catastrophically for cumuliform clouds that have fully 3D outer shapes and internal structures driven by shallow or deep convection. For these situations, the first order of business in a robust characterization by remote sensing is to abandon the slab geometry framework and determine the 3D geometry of the cloud, as a first step toward bone fide 3D cloud tomography. With this specific goal in mind, we deliver a proof-of-concept for an entirely new kind of remote sensing applicable to 3D clouds. It is based on highly simplified 3D RT and exploits multi-angular suites of cloud images at high spatial resolution. Airborne sensors like AirMSPI readily acquire such data. The key element of the reconstruction algorithm is a sophisticated solution of the nonlinear inverse problem via linearization of the forward model and an iteration scheme supported, where necessary, by adaptive regularization. Currently, the demo uses a 2D setting to show how either vertical profiles or horizontal slices of the cloud can be accurately reconstructed. Extension to 3D volumes is straightforward but the next challenge is to accommodate images at lower spatial resolution, e.g., from MISR/Terra. G. Bal, J. Chen, and A.B. Davis (2015). Reconstruction of cloud geometry from multi-angle images, Inverse Problems in Imaging (submitted).

Air flow in the boundary layer near a plate

NASA Technical Reports Server (NTRS)

Dryden, Hugh L

1937-01-01

The published data on the distribution of speed near a thin flat plate with sharp leading edge placed parallel to the flow (skin friction plate) are reviewed and the results of some additional measurements are described. The purpose of the experiments was to study the basic phenomena of boundary-layer flow under simple conditions.

Resonant infrared detector with substantially unit quantum efficiency

NASA Technical Reports Server (NTRS)

Farhoomand, Jam (Inventor); Mcmurray, Robert E., Jr. (Inventor)

1994-01-01

A resonant infrared detector includes an infrared-active layer which has first and second parallel faces and which absorbs radiation of a given wavelength. The detector also includes a first tuned reflective layer, disposed opposite the first face of the infrared-active layer, which reflects a specific portion of the radiation incident thereon and allows a specific portion of the incident radiation at the given wavelength to reach the infrared-active layer. A second reflective layer, disposed opposite the second face of the infrared-active layer, reflects back into the infrared-active layer substantially all of the radiation at the given wavelength which passes through the infrared-active layer. The reflective layers have the effect of increasing the quantum efficiency of the infrared detector relative to the quantum efficiency of the infrared-active layer alone.

Whiskerless Schottky diode

NASA Technical Reports Server (NTRS)

Bishop, William L. (Inventor); Mcleod, Kathleen A. (Inventor); Mattauch, Robert J. (Inventor)

1991-01-01

A Schottky diode for millimeter and submillimeter wave applications is comprised of a multi-layered structure including active layers of gallium arsenide on a semi-insulating gallium arsenide substrate with first and second insulating layers of silicon dioxide on the active layers of gallium arsenide. An ohmic contact pad lays on the silicon dioxide layers. An anode is formed in a window which is in and through the silicon dioxide layers. An elongated contact finger extends from the pad to the anode and a trench, preferably a transverse channel or trench of predetermined width, is formed in the active layers of the diode structure under the contact finger. The channel extends through the active layers to or substantially to the interface of the semi-insulating gallium arsenide substrate and the adjacent gallium arsenide layer which constitutes a buffer layer. Such a structure minimizes the effect of the major source of shunt capacitance by interrupting the current path between the conductive layers beneath the anode contact pad and the ohmic contact. Other embodiments of the diode may substitute various insulating or semi-insulating materials for the silicon dioxide, various semi-conductors for the active layers of gallium arsenide, and other materials for the substrate, which may be insulating or semi-insulating.

Photonic layered media

DOEpatents

Fleming, James G.; Lin, Shawn-Yu

2002-01-01

A new class of structured dielectric media which exhibit significant photonic bandstructure has been invented. The new structures, called photonic layered media, are easy to fabricate using existing layer-by-layer growth techniques, and offer the ability to significantly extend our practical ability to tailor the properties of such optical materials.

Partitioning problems in parallel, pipelined and distributed computing

NASA Technical Reports Server (NTRS)

Bokhari, S.

1985-01-01

The problem of optimally assigning the modules of a parallel program over the processors of a multiple computer system is addressed. A Sum-Bottleneck path algorithm is developed that permits the efficient solution of many variants of this problem under some constraints on the structure of the partitions. In particular, the following problems are solved optimally for a single-host, multiple satellite system: partitioning multiple chain structured parallel programs, multiple arbitrarily structured serial programs and single tree structured parallel programs. In addition, the problems of partitioning chain structured parallel programs across chain connected systems and across shared memory (or shared bus) systems are also solved under certain constraints. All solutions for parallel programs are equally applicable to pipelined programs. These results extend prior research in this area by explicitly taking concurrency into account and permit the efficient utilization of multiple computer architectures for a wide range of problems of practical interest.

Deformation and fracture of explosion-welded Ti/Al plates: A synchrotron-based study

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

E, J. C.; Huang, J. Y.; Bie, B. X.

Here, explosion-welded Ti/Al plates are characterized with energy dispersive spectroscopy and x-ray computed tomography, and exhibit smooth, well-jointed, interface. We perform dynamic and quasi-static uniaxial tension experiments on Ti/Al with the loading direction either perpendicular or parallel to the Ti/Al interface, using a mini split Hopkinson tension bar and a material testing system in conjunction with time-resolved synchrotron x-ray imaging. X-ray imaging and strain-field mapping reveal different deformation mechanisms responsible for anisotropic bulk-scale responses, including yield strength, ductility and rate sensitivity. Deformation and fracture are achieved predominantly in Al layer for perpendicular loading, but both Ti and Al layers asmore » well as the interface play a role for parallel loading. The rate sensitivity of Ti/Al follows those of the constituent metals. For perpendicular loading, single deformation band develops in Al layer under quasi-static loading, while multiple deformation bands nucleate simultaneously under dynamic loading, leading to a higher dynamic fracture strain. For parallel loading, the interface impedes the growth of deformation and results in increased ductility of Ti/Al under quasi-static loading, while interface fracture occurs under dynamic loading due to the disparity in Poisson's contraction.« less

Deformation and fracture of explosion-welded Ti/Al plates: A synchrotron-based study

DOE PAGES

E, J. C.; Huang, J. Y.; Bie, B. X.; ...

2016-08-02

Here, explosion-welded Ti/Al plates are characterized with energy dispersive spectroscopy and x-ray computed tomography, and exhibit smooth, well-jointed, interface. We perform dynamic and quasi-static uniaxial tension experiments on Ti/Al with the loading direction either perpendicular or parallel to the Ti/Al interface, using a mini split Hopkinson tension bar and a material testing system in conjunction with time-resolved synchrotron x-ray imaging. X-ray imaging and strain-field mapping reveal different deformation mechanisms responsible for anisotropic bulk-scale responses, including yield strength, ductility and rate sensitivity. Deformation and fracture are achieved predominantly in Al layer for perpendicular loading, but both Ti and Al layers asmore » well as the interface play a role for parallel loading. The rate sensitivity of Ti/Al follows those of the constituent metals. For perpendicular loading, single deformation band develops in Al layer under quasi-static loading, while multiple deformation bands nucleate simultaneously under dynamic loading, leading to a higher dynamic fracture strain. For parallel loading, the interface impedes the growth of deformation and results in increased ductility of Ti/Al under quasi-static loading, while interface fracture occurs under dynamic loading due to the disparity in Poisson's contraction.« less

Influence of vein fabric on strain distribution and fold kinematics

NASA Astrophysics Data System (ADS)

Torremans, Koen; Muchez, Philippe; Sintubin, Manuel

2014-05-01

Abundant pre-folding, bedding-parallel fibrous dolomite veins in shale are found associated with the Nkana-Mindola stratiform Cu-Co deposit in the Central African Copperbelt, Zambia. These monomineralic veins extend for several meters along strike, with a fibrous infill orthogonal to low-tortuosity vein walls. Growth morphologies vary from antitaxial with a pronounced median surface to asymmetric syntaxial, always with small but quantifiable growth competition. Subsequently, these veins were folded. In this study, we aim to constrain the kinematic fold mechanism by which strain is accommodated in these veins, estimate paleorheology at time of deformation and investigate the influence of vein fabric on deformation during folding. Finally, the influence of the deformation on known metallogenetic stages is assessed. Various deformation styles are observed, ultimately related to vein attitude across tight to close lower-order, hectometre-scale folds. In fold hinges, at low to average dips, veins are (poly-)harmonically to disharmonically folded as parasitic folds in single or multilayer systems. With increasing distance from the fold hinge, parasitic fold amplitude decreases and asymmetry increases. At high dips in the limbs, low-displacement duplication thrusts of veins at low angles to bedding are abundant. Slickenfibres and slickenlines are sub-perpendicular to fold hinges and shallow-dipping slickenfibre-step lineations are parallel to local fold hinge lines. A dip isogon analysis of reconstructed fold geometries prior to homogeneous shortening reveals type 1B parallel folds for the veins and type 1C for the matrix. Two main deformation mechanisms are identified in folded veins. Firstly, undulatory extinction, subgrains and fluid inclusions planes parallel the fibre long axis, with deformation intensity increasing away from the fold hinges, indicate intracrystalline strain accumulation. Secondly, intergranular deformation through bookshelf rotation of fibres, via collective parallel rotation of fibres and shearing along fibre grain boundaries, is clearly observed under cathodoluminescence. We analysed the internal strain distribution by quantifying simple shear strain caused by deflection of the initially orthogonal fibres relative to layer inclination at a given position across the fold. Shear angle, and thus shear strain, steadily increases towards the limbs away from the fold hinge. Comparison of observed shear strain to theoretical distribution for kinematic mechanisms, amongst other lines of evidence, clearly points to pure flexural flow followed by homogeneous shortening. As flexural flow is not the expected kinematic folding mechanism for competent layers in an incompetent shale matrix, our analysis shows that the internal vein fabric in these dolomite veins can exhibit a first-order influence on folding mechanisms. In addition, quantitative analysis shows that these veins acted as rigid objects with high viscosity contrast relative to the incompetent carbonaceous shale, rather than as semi-passive markers. Later folding-related syn-orogenic veins, intensely mineralised with Cu-Co sulphides, are strongly related to deformation of these pre-folding veins. The high viscosity contrast created by the pre-folding fibrous dolomite veins was therefore essential in creating transient permeability for subsequent mineralising stages in the veining history.

HYDROGEN ELECTROLYZER FLOW DISTRIBUTOR MODEL

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

Shadday, M

2006-09-28

The hybrid sulfur process (HyS) hydrogen electrolyzer consists of a proton exchange membrane (PEM) sandwiched between two porous graphite layers. An aqueous solution of sulfuric acid with dissolved SO{sub 2} gas flows parallel to the PEM through the porous graphite layer on the anode side of the electrolyzer. A flow distributor, consisting of a number of parallel channels acting as headers, promotes uniform flow of the anolyte fluid through the porous graphite layer. A numerical model of the hydraulic behavior of the flow distributor is herein described. This model was developed to be a tool to aid the design ofmore » flow distributors. The primary design objective is to minimize spatial variations in the flow through the porous graphite layer. The hydraulic data from electrolyzer tests consists of overall flowrate and pressure drop. Internal pressure and flow distributions are not measured, but these details are provided by the model. The model has been benchmarked against data from tests of the current electrolyzer. The model reasonably predicts the viscosity effect of changing the fluid from water to an aqueous solution of 30 % sulfuric acid. The permeability of the graphite layer was the independent variable used to fit the model to the test data, and the required permeability for a good fit is within the range literature values for carbon paper. The model predicts that reducing the number of parallel channels by 50 % will substantially improve the uniformity of the flow in the porous graphite layer, while maintaining an acceptable pressure drop across the electrolyzer. When the size of the electrolyzer is doubled from 2.75 inches square to 5.5 inches square, the same number of channels as in the current design will be adequate, but it is advisable to increase the channel cross-sectional flow area. This is due to the increased length of the channels.« less

Twelve Channel Optical Fiber Connector Assembly: From Commercial Off the Shelf to Space Flight Use

NASA Technical Reports Server (NTRS)

Ott, Melaine N.

1998-01-01

The commercial off the shelf (COTS) twelve channel optical fiber MTP array connector and ribbon cable assembly is being validated for space flight use and the results of this study to date are presented here. The interconnection system implemented for the Parallel Fiber Optic Data Bus (PFODB) physical layer will include a 100/140 micron diameter optical fiber in the cable configuration among other enhancements. As part of this investigation, the COTS 62.5/125 microns optical fiber cable assembly has been characterized for space environment performance as a baseline for improving the performance of the 100/140 micron diameter ribbon cable for the Parallel FODB application. Presented here are the testing and results of random vibration and thermal environmental characterization of this commercial off the shelf (COTS) MTP twelve channel ribbon cable assembly. This paper is the first in a series of papers which will characterize and document the performance of Parallel FODB's physical layer from COTS to space flight worthy.

Extending Human Hematopoietic Stem Cell Survival In Vitro with Adipocytes

PubMed Central

Glettig, Dean Liang

2013-01-01

Abstract Human hematopoietic stem cells (hHSCs) cannot be maintained in vitro for extended time periods because they rapidly differentiate or die. To extend in vitro culture time, researchers have made attempts to use human mesenchymal stem cells (hMSCs) to create feeder layers that mimic the stem cell niche. We have conducted an array of experiments including adipocytes in these feeder layers that inhibit hHSC differentiation and by that prolong stem cell survival in vitro. The amount of CD34+ cells was quantified using flow cytometry. In a first experiment, feeder layers of undifferentiated hMSCs were compared with feeder layers differentiated toward osteoblasts or adipocytes using minimal medium, showing the highest survival rate where adipocytes were included. The same conclusion was drawn in a second experiment in comparing hMSCs with adipogenic feeder cells, using a culture medium supplemented with a cocktail of hHSC growth factors. In a third experiment, it was shown that direct cell–cell contact is necessary for the supportive effect of the feeder layers. In a fourth and fifth experiment the amount of adipocytes in the feeder layers were varied, and in all experiments a higher amount of adipocytes in the feeder layers showed a less rapid decay of CD34+ cells at later time points. We therefore concluded that adipocytes assist in suppressing hHSC differentiation and aid in prolonging their survival in vitro. PMID:23741628

Wheel-type magnetic refrigerator

DOEpatents

Barclay, J.A.

1983-10-11

The disclosure is directed to a wheel-type magnetic refrigerator capable of cooling over a large temperature range. Ferromagnetic or paramagnetic porous materials are layered circumferentially according to their Curie temperature. The innermost layer has the lowest Curie temperature and the outermost layer has the highest Curie temperature. The wheel is rotated through a magnetic field perpendicular to the axis of the wheel and parallel to its direction of rotation. A fluid is pumped through portions of the layers using inner and outer manifolds to achieve refrigeration of a thermal load. 7 figs.

Benard and Marangoni convection in multiple liquid layers

NASA Technical Reports Server (NTRS)

Koster, Jean N.; Prakash, A.; Fujita, D.; Doi, T.

1992-01-01

Convective fluid dynamics of immiscible double and triple liquid layers are considered. First results on multilayer convective flow, in preparation for spaceflight experiment aboard IML-2 (International Microgravity Laboratory), are discussed. Convective flow in liquid layers with one or two horizontal interfaces with heat flow applied parallel to them is one of the systems investigated. The second system comprises two horizontally layered immiscible liquids heated from below and cooled from above, that is, heat flow orthogonal to the interface. In this system convection results due to the classical Benard instability.

Methods of three-dimensional electrophoretic deposition for ceramic and cermet applications and systems thereof

DOEpatents

Rose, Klint Aaron; Kuntz, Joshua D.; Worsley, Marcus

2016-09-27

A ceramic, metal, or cermet according to one embodiment includes a first layer having a gradient in composition, microstructure and/or density in an x-y plane oriented parallel to a plane of deposition of the first layer. A ceramic according to another embodiment includes a plurality of layers comprising particles of a non-cubic material, wherein each layer is characterized by the particles of the non-cubic material being aligned in a common direction. Additional products and methods are also disclosed.

Extending the Diffuse Layer Model of Surface Acidity Constant Behavior: IV. Diffuse Layer Charge/Potential Relationships

EPA Science Inventory

Most current electrostatic surface complexation models describing ionic binding at the particle/water interface rely on the use of Poisson - Boltzmann (PB) theory for relating diffuse layer charge densities to diffuse layer electrostatic potentials. PB theory is known to contain ...

Performance Characteristics of the Multi-Zone NAS Parallel Benchmarks

NASA Technical Reports Server (NTRS)

Jin, Haoqiang; VanderWijngaart, Rob F.

2003-01-01

We describe a new suite of computational benchmarks that models applications featuring multiple levels of parallelism. Such parallelism is often available in realistic flow computations on systems of grids, but had not previously been captured in bench-marks. The new suite, named NPB Multi-Zone, is extended from the NAS Parallel Benchmarks suite, and involves solving the application benchmarks LU, BT and SP on collections of loosely coupled discretization meshes. The solutions on the meshes are updated independently, but after each time step they exchange boundary value information. This strategy provides relatively easily exploitable coarse-grain parallelism between meshes. Three reference implementations are available: one serial, one hybrid using the Message Passing Interface (MPI) and OpenMP, and another hybrid using a shared memory multi-level programming model (SMP+OpenMP). We examine the effectiveness of hybrid parallelization paradigms in these implementations on three different parallel computers. We also use an empirical formula to investigate the performance characteristics of the multi-zone benchmarks.

Studies of acoustic effects on a flow boundary layer in air

NASA Technical Reports Server (NTRS)

Mechel, F.; Schilz, W.

1986-01-01

Effects of sound fields on the flow boundary layer on a flat plate subjected to a parallel flow are studied. The boundary layer is influenced by controlling the stagnation point flow at the front edge of the plate. Depending on the Reynolds number and sound frequency, excitation or suppression of turbulent is observed. Measurements were taken at wind velocities between 10 and 30 m/sec and sound frequencies between 0.2 and 3.0 kHz.

Comparison with Analytical Solution: Generation and Radiation of Acoustic Waves from a 2-D Shear Layer

NASA Technical Reports Server (NTRS)

Dahl, Milo D.

2000-01-01

An acoustic source inside of a 2-D jet excites an instability wave in the shear layer resulting in sound radiating away from the shear layer. Solve the linearized Euler equations to predict the sound radiation outside of the jet. The jet static pressure is assumed to be constant. The jet flow is parallel and symmetric about the x-axis. Use a symmetry boundary condition along the x-axis.

CMUTs with High-K Atomic Layer Deposition Dielectric Material Insulation Layer

PubMed Central

Xu, Toby; Tekes, Coskun; Degertekin, F. Levent

2014-01-01

Use of high-κ dielectric, atomic layer deposition (ALD) materials as an insulation layer material for capacitive micromachined ultrasonic transducers (CMUTs) is investigated. The effect of insulation layer material and thickness on CMUT performance is evaluated using a simple parallel plate model. The model shows that both high dielectric constant and the electrical breakdown strength are important for the dielectric material, and significant performance improvement can be achieved, especially as the vacuum gap thickness is reduced. In particular, ALD hafnium oxide (HfO2) is evaluated and used as an improvement over plasma-enhanced chemical vapor deposition (PECVD) silicon nitride (SixNy) for CMUTs fabricated by a low-temperature, complementary metal oxide semiconductor transistor-compatible, sacrificial release method. Relevant properties of ALD HfO2 such as dielectric constant and breakdown strength are characterized to further guide CMUT design. Experiments are performed on parallel fabricated test CMUTs with 50-nm gap and 16.5-MHz center frequency to measure and compare pressure output and receive sensitivity for 200-nm PECVD SixNy and 100-nm HfO2 insulation layers. Results for this particular design show a 6-dB improvement in receiver output with the collapse voltage reduced by one-half; while in transmit mode, half the input voltage is needed to achieve the same maximum output pressure. PMID:25474786

Multi-color interferometric observations of Mira stars

NASA Technical Reports Server (NTRS)

Mennesson, B.; Creech-Eakman, M.; Thompson, B. B.; Foresto, V. Coude du; Merand, A.; Ridgway, S.; Perrin, G.

2002-01-01

Interferometric observations in the atmospheric windows of the near infrared (1 to 4 microns) can be efficiently used to probe the chemical composition of Miras atmosphere and provide direct measurements of extended gas layers around these stars. This is illustrated by recent Miras observations carried out with the FLUOR instrument of the IOTA interferometer (Mennesson et al. 2002, and Perrin et al. proceedings of this conference) and with the PTI test-bed (Thompson 2002, Thompson et al. 2002). These visibility measurements show evidence for continuum emission from very extended ( 2-3 stellar radii) semi-transparent gaseous atmospheric layers, and large apparent diameter changes with pulsation phase. Interestingly these observations are consistent with the extended molecular gas layers (H20, CO ...) already inferred around some of these objects from IS0 and high resolution ground-based FTS infrared spectra.

Double layer zinc-UDP coordination polymers: structure and properties.

PubMed

Qiu, Qi-Ming; Gu, Leilei; Ma, Hongwei; Yan, Li; Liu, Minghua; Li, Hui

2018-05-17

A homochiral Zn-UDP coordination polymer with an alternating parallel ABAB sequence was constructed and studied by X-ray single crystal diffraction analysis. Its crystal structure shows that there are potentially open sites in the 2D layers. The activation of the sites makes the coordination polymer a fluorescent sensor for novel heterogeneous detection of amino acids.

Applications and accuracy of the parallel diagonal dominant algorithm

NASA Technical Reports Server (NTRS)

Sun, Xian-He

1993-01-01

The Parallel Diagonal Dominant (PDD) algorithm is a highly efficient, ideally scalable tridiagonal solver. In this paper, a detailed study of the PDD algorithm is given. First the PDD algorithm is introduced. Then the algorithm is extended to solve periodic tridiagonal systems. A variant, the reduced PDD algorithm, is also proposed. Accuracy analysis is provided for a class of tridiagonal systems, the symmetric, and anti-symmetric Toeplitz tridiagonal systems. Implementation results show that the analysis gives a good bound on the relative error, and the algorithm is a good candidate for the emerging massively parallel machines.

PARAMESH: A Parallel Adaptive Mesh Refinement Community Toolkit

NASA Technical Reports Server (NTRS)

MacNeice, Peter; Olson, Kevin M.; Mobarry, Clark; deFainchtein, Rosalinda; Packer, Charles

1999-01-01

In this paper, we describe a community toolkit which is designed to provide parallel support with adaptive mesh capability for a large and important class of computational models, those using structured, logically cartesian meshes. The package of Fortran 90 subroutines, called PARAMESH, is designed to provide an application developer with an easy route to extend an existing serial code which uses a logically cartesian structured mesh into a parallel code with adaptive mesh refinement. Alternatively, in its simplest use, and with minimal effort, it can operate as a domain decomposition tool for users who want to parallelize their serial codes, but who do not wish to use adaptivity. The package can provide them with an incremental evolutionary path for their code, converting it first to uniformly refined parallel code, and then later if they so desire, adding adaptivity.

Atmospheric tomography using a fringe pattern in the sodium layer.

PubMed

Baharav, Y; Ribak, E N; Shamir, J

1994-02-15

We wish to measure and separate the contribution of atmospheric turbulent layers for multiconjugate adaptive optics. To this end, we propose to create a periodic fringe pattern in the sodium layer and image it with a modified Hartmann sensor. Overlapping sections of the fringes are imaged by a lenslet array onto contiguous areas in a large-format camera. Low-layer turbulence causes an overall shift of the fringe pattern in each lenslet, and high-attitude turbulence results in internal deformations in the pattern. Parallel Fourier analysis permits separation of the atmospheric layers. Two mirrors, one conjugate to a ground layer and the other conjugate to a single high-altitude layer, are shown to widen the field of view significantly compared with existing methods.

Parametric Data from a Wind Tunnel Test on a Rocket-Based Combined-Cycle Engine Inlet

NASA Technical Reports Server (NTRS)

Fernandez, Rene; Trefny, Charles J.; Thomas, Scott R.; Bulman, Mel J.

2001-01-01

A 40-percent scale model of the inlet to a rocket-based combined-cycle (RBCC) engine was tested in the NASA Glenn Research Center 1- by 1-Foot Supersonic Wind Tunnel (SWT). The full-scale RBCC engine is scheduled for test in the Hypersonic Tunnel Facility (HTF) at NASA Glenn's Plum Brook Station at Mach 5 and 6. This engine will incorporate the configuration of this inlet model which achieved the best performance during the present experiment. The inlet test was conducted at Mach numbers of 4.0, 5.0, 5.5, and 6.0. The fixed-geometry inlet consists of an 8 deg.. forebody compression plate, boundary layer diverter, and two compressive struts located within 2 parallel sidewalls. These struts extend through the inlet, dividing the flowpath into three channels. Test parameters investigated included strut geometry, boundary layer ingestion, and Reynolds number (Re). Inlet axial pressure distributions and cross-sectional Pitot-pressure surveys at the base of the struts were measured at varying back-pressures. Inlet performance and starting data are presented. The inlet chosen for the RBCC engine self-started at all Mach numbers from 4 to 6. Pitot-pressure contours showed large flow nonuniformity on the body-side of the inlet. The inlet provided adequate pressure recovery and flow quality for the RBCC cycle even with the flow separation.

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

Welcome, Michael L.; Bell, Christian S.

GASNet (Global-Address Space Networking) is a language-independent, low-level networking layer that provides network-independent, high-performance communication primitives tailored for implementing parallel global address space SPMD languages such as UPC and Titanium. The interface is primarily intended as a compilation target and for use by runtime library writers (as opposed to end users), and the primary goals are high performance, interface portability, and expressiveness. GASNet is designed specifically to support high-performance, portable implementations of global address space languages on modern high-end communication networks. The interface provides the flexibility and extensibility required to express a wide variety of communication patterns without sacrificing performancemore » by imposing large computational overheads in the interface. The design of the GASNet interface is partitioned into two layers to maximize porting ease without sacrificing performance: the lower level is a narrow but very general interface called the GASNet core API - the design is basedheavily on Active Messages, and is implemented directly on top of each individual network architecture. The upper level is a wider and more expressive interface called GASNet extended API, which provides high-level operations such as remote memory access and various collective operations. This release implements GASNet over MPI, the Quadrics "elan" API, the Myrinet "GM" API and the "LAPI" interface to the IBM SP switch. A template is provided for adding support for additional network interfaces.« less

Cross-sectional aspect ratio modulated electronic properties in Si/Ge core/shell nanowires

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

Liu, Nuo; Lu, Ning; Yao, Yong-Xin

2013-02-28

Electronic structures of (4, n) and (m, 4) (the NW has m layers parallel to the {1 1 1} facet and n layers parallel to {1 1 0}) Si/Ge core/shell nanowires (NWs) along the [1 1 2] direction with cross-sectional aspect ratio (m/n) from 0.36 to 2.25 are studied by first-principles calculations. An indirect to direct band gap transition is observed as m/n decreases, and the critical values of m/n and diameter for the transition are also estimated. The size of the band gap also depends on the aspect ratio. These results suggest that m/n plays an important role inmore » modulating the electronic properties of the NWs.« less

Compressional residual stress in Bastogne boudins revealed by synchrotron X-ray microdiffraction

DOE PAGES

Chen, Kai; Kunz, Martin; Li, Yao; ...

2016-06-22

Lattice distortions in crystals can be mapped at the micron scale using synchrotron X-ray Laue microdiffraction (μXRD). From lattice distortions the shape and orientation of the elastic strain tensor can be derived and interpreted in terms of residual stress. We apply the new method to vein quartz from the original boudinage locality at Bastogne, Belgium. Furthermore, a long-standing debate surrounds the kinematics of the Bastogne boudins. The μXRD measurements reveal a shortening residual elastic strain, perpendicular to the vein wall, corroborating the model that the Bastogne boudins formed by layer-parallel shortening and not by layer-parallel extension, as is in themore » geological community generally inferred by the process of boudinage.« less

49 CFR 393.122 - What are the rules for securing paper rolls?

Code of Federal Regulations, 2010 CFR

2010-10-01

... be loaded on a layer of paper rolls beneath unless the lower layer extends to the front of the vehicle. (2) Paper rolls in the second and subsequent layers must be prevented from forward, rearward or lateral movement by means as allowed for the bottom layer, or by use of a blocking roll from a lower layer...

Force user's manual, revised

NASA Technical Reports Server (NTRS)

Jordan, Harry F.; Benten, Muhammad S.; Arenstorf, Norbert S.; Ramanan, Aruna V.

1987-01-01

A methodology for writing parallel programs for shared memory multiprocessors has been formalized as an extension to the Fortran language and implemented as a macro preprocessor. The extended language is known as the Force, and this manual describes how to write Force programs and execute them on the Flexible Computer Corporation Flex/32, the Encore Multimax and the Sequent Balance computers. The parallel extension macros are described in detail, but knowledge of Fortran is assumed.

SpecTAD

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

Zamora, Richard; Voter, Arthur; Uberuaga, Bla

2017-10-23

The SpecTAD software represents a refactoring of the Temperature Accelerated Dynamics (TAD2) code authored by Arthur F. Voter and Blas P. Uberuaga (LA-CC-02-05). SpecTAD extends the capabilities of TAD2, by providing algorithms for both temporal and spatial parallelism. The novel algorithms for temporal parallelism include both speculation and replication based techniques. SpecTAD also offers the optional capability to dynamically link to the open-source LAMMPS package.

Neutronic reactor construction

DOEpatents

Huston, Norman E.

1976-07-06

1. A neutronic reactor comprising a moderator including horizontal layers formed of horizontal rows of graphite blocks, alternate layers of blocks having the rows extending in one direction, the remaining alternate layers having the rows extending transversely to the said one direction, alternate rows of blocks in one set of alternate layers having longitudinal ducts, the moderator further including slotted graphite tubes positioned in the ducts, the reactor further comprising an aluminum coolant tube positioned within the slotted tube in spaced relation thereto, bodies of thermal-neutron-fissionable material, and jackets enclosing the bodies and being formed of a corrosion-resistant material having a low neutron-capture cross section, the bodies and jackets being positioned within the coolant tube so that the jackets are spaced from the coolant tube.

Spectral enstrophy budget in a shear-less flow with turbulent/non-turbulent interface

NASA Astrophysics Data System (ADS)

Cimarelli, Andrea; Cocconi, Giacomo; Frohnapfel, Bettina; De Angelis, Elisabetta

2015-12-01

A numerical analysis of the interaction between decaying shear free turbulence and quiescent fluid is performed by means of global statistical budgets of enstrophy, both, at the single-point and two point levels. The single-point enstrophy budget allows us to recognize three physically relevant layers: a bulk turbulent region, an inhomogeneous turbulent layer, and an interfacial layer. Within these layers, enstrophy is produced, transferred, and finally destroyed while leading to a propagation of the turbulent front. These processes do not only depend on the position in the flow field but are also strongly scale dependent. In order to tackle this multi-dimensional behaviour of enstrophy in the space of scales and in physical space, we analyse the spectral enstrophy budget equation. The picture consists of an inviscid spatial cascade of enstrophy from large to small scales parallel to the interface moving towards the interface. At the interface, this phenomenon breaks, leaving place to an anisotropic cascade where large scale structures exhibit only a cascade process normal to the interface thus reducing their thickness while retaining their lengths parallel to the interface. The observed behaviour could be relevant for both the theoretical and the modelling approaches to flow with interacting turbulent/nonturbulent regions. The scale properties of the turbulent propagation mechanisms highlight that the inviscid turbulent transport is a large-scale phenomenon. On the contrary, the viscous diffusion, commonly associated with small scale mechanisms, highlights a much richer physics involving small lengths, normal to the interface, but at the same time large scales, parallel to the interface.

Two interpenetrating Cu{sup II}/Ni{sup II}-coordinated polymers based on an unsymmetrical bifunctional N/O-tectonic: Syntheses, structures and magnetic properties

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

Liu, Yong-Liang; Department of Chemistry and Chemical Engineering, Shaanxi Key Laboratory of Comprehensive Utilization of Tailings Resources, Shang Luo University, Shang Luo 726000; Wu, Ya-Pan

2015-03-15

Two new interpenetrating Cu{sup II}/Ni{sup II} coordination polymers, based on a unsymmetrical bifunctional N/O-tectonic 3-(pyrid-4′-yl)-5-(4″-carbonylphenyl)-1,2,4-triazolyl (H{sub 2}pycz), ([Cu-(Hpycz){sub 2}]·2H{sub 2}O){sub n} (1) and ([Ni(Hpycz){sub 2}]·H{sub 2}O){sub n} (2), have been solvothermally synthesized and structure characterization. Single crystal X-ray analysis indicates that compound 1 shows 2-fold parallel interpenetrated 4{sup 4}-sql layers with the same handedness. The overall structure of 1 is achiral—in each layer of doubly interpenetrating nets, the two individual nets have the opposite handedness to the corresponding nets in the adjoining layers—while 2 features a rare 8-fold interpenetrating 6{sup 6}-dia network that belongs to class IIIa interpenetration. In addition,more » compounds 1 and 2 both show similar paramagnetic characteristic properties. - Graphical abstract: Two new Cu(II)/Ni(II) coordination polymers present 2D parallel 2-fold interpenetrated 4{sup 4}-sql layers and a rare 3D 8-fold interpenetrating 6{sup 6}-dia network. In addition, magnetic susceptibility measurements show similar paramagnetic characteristic for two complexes. - Highlights: • A new unsymmetrical bifunctional N/O-tectonic as 4-connected spacer. • A 2-fold parallel interpenetrated sql layer with the same handedness. • A rare 8-fold interpenetrating dia network (class IIIa)« less

Facilitating arrhythmia simulation: the method of quantitative cellular automata modeling and parallel running

PubMed Central

Zhu, Hao; Sun, Yan; Rajagopal, Gunaretnam; Mondry, Adrian; Dhar, Pawan

2004-01-01

Background Many arrhythmias are triggered by abnormal electrical activity at the ionic channel and cell level, and then evolve spatio-temporally within the heart. To understand arrhythmias better and to diagnose them more precisely by their ECG waveforms, a whole-heart model is required to explore the association between the massively parallel activities at the channel/cell level and the integrative electrophysiological phenomena at organ level. Methods We have developed a method to build large-scale electrophysiological models by using extended cellular automata, and to run such models on a cluster of shared memory machines. We describe here the method, including the extension of a language-based cellular automaton to implement quantitative computing, the building of a whole-heart model with Visible Human Project data, the parallelization of the model on a cluster of shared memory computers with OpenMP and MPI hybrid programming, and a simulation algorithm that links cellular activity with the ECG. Results We demonstrate that electrical activities at channel, cell, and organ levels can be traced and captured conveniently in our extended cellular automaton system. Examples of some ECG waveforms simulated with a 2-D slice are given to support the ECG simulation algorithm. A performance evaluation of the 3-D model on a four-node cluster is also given. Conclusions Quantitative multicellular modeling with extended cellular automata is a highly efficient and widely applicable method to weave experimental data at different levels into computational models. This process can be used to investigate complex and collective biological activities that can be described neither by their governing differentiation equations nor by discrete parallel computation. Transparent cluster computing is a convenient and effective method to make time-consuming simulation feasible. Arrhythmias, as a typical case, can be effectively simulated with the methods described. PMID:15339335

Anti-parallel versus Component Reconnection at the Earth Magnetopause

NASA Astrophysics Data System (ADS)

Trattner, K. J.; Burch, J. L.; Ergun, R.; Eriksson, S.; Fuselier, S. A.; Gomez, R. G.; Giles, B. L.; Steven, P. M.; Strangeway, R. J.; Wilder, F. D.

2017-12-01

Magnetic reconnection at the Earth's magnetopause is discussed and has been observed as anti-parallel and component reconnection. While anti-parallel reconnection occurs between magnetic field lines of (ideally) exactly opposite polarity, component reconnection (also known as the tilted X-line model) predicts the location of the reconnection line to be anchored at the sub-solar point and extend continuously along the dayside magnetopause, while the ratio of the IMF By/Bz component determines the tilt of the X-line relative to the equatorial plane.A reconnection location prediction model known as the Maximum Magnetic Shear Model combines these two scenarios. The model predicts that during dominant IMF By conditions, magnetic reconnection occurs along an extended line across the dayside magnetopause but generally not through the sub-solar point (as predicted in the original tilted X-line model). Rather, the line follows the ridge of maximum magnetic shear across the dayside magnetopause. In contrast, for dominant IMF Bz (155° < tan-1(By/Bz) < 205°) or dominant Bx (|Bx|/B > 0.7) conditions, the reconnection location bifurcates and traces to high-latitudes, in close agreement with the anti-parallel reconnection scenario, and does not cross the dayside magnetopause as a single tilted reconnection line. Using observations from the Magnetospheric MultiScale missions during a magnetopause crossing when the IMF rotated from an dominate IMF BZ to a dominant IMF BY field we will investigate when the transition between the anti-parallel and tilted X-line scenarios occurs.

Machine Learning Based Online Performance Prediction for Runtime Parallelization and Task Scheduling

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

Li, J; Ma, X; Singh, K

2008-10-09

With the emerging many-core paradigm, parallel programming must extend beyond its traditional realm of scientific applications. Converting existing sequential applications as well as developing next-generation software requires assistance from hardware, compilers and runtime systems to exploit parallelism transparently within applications. These systems must decompose applications into tasks that can be executed in parallel and then schedule those tasks to minimize load imbalance. However, many systems lack a priori knowledge about the execution time of all tasks to perform effective load balancing with low scheduling overhead. In this paper, we approach this fundamental problem using machine learning techniques first to generatemore » performance models for all tasks and then applying those models to perform automatic performance prediction across program executions. We also extend an existing scheduling algorithm to use generated task cost estimates for online task partitioning and scheduling. We implement the above techniques in the pR framework, which transparently parallelizes scripts in the popular R language, and evaluate their performance and overhead with both a real-world application and a large number of synthetic representative test scripts. Our experimental results show that our proposed approach significantly improves task partitioning and scheduling, with maximum improvements of 21.8%, 40.3% and 22.1% and average improvements of 15.9%, 16.9% and 4.2% for LMM (a real R application) and synthetic test cases with independent and dependent tasks, respectively.« less

NEUTRONIC REACTORS

DOEpatents

Wigner, E.P.

1960-11-22

A nuclear reactor is described wherein horizontal rods of thermal- neutron-fissionable material are disposed in a body of heavy water and extend through and are supported by spaced parallel walls of graphite.

Aerosol-Jet-Printing silicone layers and electrodes for stacked dielectric elastomer actuators in one processing device

NASA Astrophysics Data System (ADS)

Reitelshöfer, Sebastian; Göttler, Michael; Schmidt, Philip; Treffer, Philipp; Landgraf, Maximilian; Franke, Jörg

2016-04-01

In this contribution we present recent findings of our efforts to qualify the so called Aerosol-Jet-Printing process as an additive manufacturing approach for stacked dielectric elastomer actuators (DEA). With the presented system we are able to print the two essential structural elements dielectric layer and electrode in one machine. The system is capable of generating RTV-2 silicone layers made of Wacker Elastosil P 7670. Therefore, two aerosol streams of both precursor components A and B are generated in parallel and mixed in one printing nozzle that is attached to a 4-axis kinematic. At maximum speed the printing of one circular Elastosil layer with a calculated thickness of 10 μm and a diameter of 1 cm takes 12 seconds while the process keeps stable for 4.5 hours allowing a quite high overall material output and the generation of numerous silicone layers. By adding a second printing nozzle and the infrastructure to generate a third aerosol, the system is also capable of printing inks with conductive particles in parallel to the silicone. We have printed a reduced graphene oxide (rGO) ink prepared in our lab to generate electrodes on VHB 4905, Elastosil foils and finally on Aerosol-Jet-Printed Elastosil layers. With rGO ink printed on Elastosil foil, layers with a 4-point measured sheet resistance as low as 4 kΩ can be realized leaving room for improving the electrode printing time, which at the moment is not as good as the quite good time-frame for printing the silicone layers. Up to now we have used the system to print a fully functional two-layer stacked DEA to demonstrate the principle of continuously 3D printing actuators.

The effect of two pre-cryopreservation single layer colloidal centrifugation protocols in combination with different freezing extenders on the fragmentation dynamics of thawed equine sperm DNA

PubMed Central

2012-01-01

Background Variability among stallions in terms of semen cryopreservation quality renders it difficult to arrive at a standardized cryopreservation method. Different extenders and processing techniques (such us colloidal centrifugation) are used in order to optimize post-thaw sperm quality. Sperm chromatin integrity analysis is an effective tool for assessing such quality. The aim of the present study was to compare the effect of two single layer colloidal centrifugation protocols (prior to cryopreservation) in combination with three commercial freezing extenders on the post-thaw chromatin integrity of equine sperm samples at different post-thaw incubation (37°C) times (i.e., their DNA fragmentation dynamics). Results Post-thaw DNA fragmentation levels in semen samples subjected to either of the colloidal centrifugation protocols were significantly lower (p<0.05) immediately after thawing and after 4 h of incubation at 37°C compared to samples that underwent standard (control) centrifugation. The use of InraFreeze® extender was associated with significantly less DNA fragmentation than the use of Botu-Crio® extender at 6 h of incubation, and than the use of either Botu-Crio® or Gent® extender at 24 h of incubation (p<0.05). Conclusions These results suggest that single layer colloidal centrifugation performed with extended or raw semen prior to cryopreservation reduces DNA fragmentation during the first four hours after thawing. Further studies are needed to determine the influence of freezing extenders on equine sperm DNA fragmentation dynamics. PMID:23217215

Three dimensional interactive display

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

2005-01-01

A three-dimensional (3-D) interactive display and method of forming the same, includes a transparent capaciflector (TC) camera formed on a transparent shield layer on the screen surface. A first dielectric layer is formed on the shield layer. A first wire layer is formed on the first dielectric layer. A second dielectric layer is formed on the first wire layer. A second wire layer is formed on the second dielectric layer. Wires on the first wire layer and second wire layer are grouped into groups of parallel wires with a turnaround at one end of each group and a sensor pad at the opposite end. An operational amplifier is connected to each of the sensor pads and the shield pad biases the pads and receives a signal from connected sensor pads in response to intrusion of a probe. The signal is proportional to probe location with respect to the monitor screen.

Influence of emissive layer thickness on electrical characteristics of polyfluorene copolymer based polymer light emitting diodes

NASA Astrophysics Data System (ADS)

Das, D.; Gopikrishna, P.; Singh, A.; Dey, A.; Iyer, P. K.

2016-04-01

Polymer light emitting diodes (PLEDs) with a device configuration of ITO/PEDOT:PSS/PFONPN01 [Poly [2,7-(9,9’-dioctylfluorene)-co-N-phenyl-1,8-naphthalimide (99:01)]/LiF/Al have been fabricated by varying the emissive layer (EML) thickness (40/65/80/130 nm) and the influence of EML thickness on the electrical characteristics of PLED has been studied. PLED can be modelled as a simple combination of resistors and capacitors. The impedance spectroscopy analysis showed that the devices with different EML thickness had different values of parallel resistance (RP) and the parallel capacitance (CP). The impedance of the devices is found to increase with increasing EML thickness resulting in an increase in the driving voltage. The device with an emissive layer thickness of 80nm, spin coated from a solution of concentration 15 mg/mL is found to give the best device performance with a maximum brightness value of 5226 cd/m2.

Anisotropy in Third-Order Nonlinear Optical Susceptibility of a Squarylium Dye in a Nematic Liquid Crystal

NASA Astrophysics Data System (ADS)

Jin, Zhao-Hui; Li, Zhong-Yu; Kasatani, Kazuo; Okamoto, Hiroaki

2006-03-01

A squarylium dye is dissolved in 4-cyano-4'-pentylbiphenyl (5CB) and oriented by sandwiching mixtures between two pieces of rubbed glass plates. The optical absorption spectra of the oriented squarylium dye-5CB layers exhibit high anisotropy. The third-order nonlinear optical responses and susceptibilities χ(3)e of squarylium dye in 5CB are measured with light polarizations parallel and perpendicular to the orientational direction by the resonant femtosecond degenerate four-wave mixing (DFWM) technique. Temporal profiles of the DFWM signal of the oriented squarylium dye-5CB layers with light polarizations parallel and perpendicular to the orientational direction are measured with a time resolution of 0.3 ps (FWHM), and are found to consist of two components, i.e., the coherent instantaneous nonlinear response and slow response due to the formation of excited molecules. A high anisotropic ratio of χ(3)e, 10.8±1.2, is observed for the oriented layers.

A 3D resistivity model derived from the transient electromagnetic data observed on the Araba fault, Jordan

NASA Astrophysics Data System (ADS)

Rödder, A.; Tezkan, B.

2013-01-01

72 inloop transient electromagnetic soundings were carried out on two 2 km long profiles perpendicular and two 1 km and two 500 m long profiles parallel to the strike direction of the Araba fault in Jordan which is the southern part of the Dead Sea transform fault indicating the boundary between the African and Arabian continental plates. The distance between the stations was on average 50 m. The late time apparent resistivities derived from the induced voltages show clear differences between the stations located at the eastern and at the western part of the Araba fault. The fault appears as a boundary between the resistive western (ca. 100 Ωm) and the conductive eastern part (ca. 10 Ωm) of the survey area. On profiles parallel to the strike late time apparent resistivities were almost constant as well in the time dependence as in lateral extension at different stations, indicating a 2D resistivity structure of the investigated area. After having been processed, the data were interpreted by conventional 1D Occam and Marquardt inversion. The study using 2D synthetic model data showed, however, that 1D inversions of stations close to the fault resulted in fictitious layers in the subsurface thus producing large interpretation errors. Therefore, the data were interpreted by a 2D forward resistivity modeling which was then extended to a 3D resistivity model. This 3D model explains satisfactorily the time dependences of the observed transients at nearly all stations.

Igneous Crystallization and Localized Deformation in the Shallow Mantle beneath Slow Spreading Ridges

NASA Astrophysics Data System (ADS)

Kelemen, P.; Kikawa, E.; Miller, J.

2004-05-01

Building upon previous work, and incorporating new results from ODP Leg 209, we will provide a synthesis of melt migration mechanisms beneath oceanic spreading ridges, with an emphasis on the thick conductive boundary layer extending to about 20 km depth beneath slow-spreading ridges. In adiabatically upwelling mantle, ascending melt acts as a "solvent", creating additional melt by dissolving pyroxene in surrounding wall rocks, and thus forming high porosity dissolution channels. Mature dissolution channels lack pyroxene, and allow migration of pyroxene-undersaturated melt through the shallow mantle. In conductively cooled mantle, melts begin to crystallize due to cooling, and in addition reactions with surrounding peridotite consume melt. Where melt fluxes are large, this can create a permeability barrier that ultimately leads to an upstream increase in melt pressure and, in some cases, causes hydrofracture and magma ascent in dikes. Where melt fluxes are small, porous flow of crystallizing melt continues upward into the conductive boundary layer. This leads to formation of "impregnated peridotite", with igneous plag and pyroxene precipitated along olivine grain boundaries, and forms melts that are in equilibrium with lherzolite assemblages at relatively low pressures. Impregnated peridotites from ODP Leg 209 have "equilibrated" textures and contain olivine, 2 pyroxenes, plag and Cr-rich spinel. Mg#, Cr# and Ni are high, extending to residual peridotite values. Crystallization pressure can be estimated using local lava compositions. 87 MORB glasses from 14 to 16°N with Mg# from 60 to 73 [from PetDB] could be plagioclase lherzolite saturated at 5.4 kb (+ - 1.4 kb 2 sigma) and 1220 C (+ - 16°C 2 sigma) [using Kinzler & Grove, JGR 92]. Plag ranges from An 60 to 75. Subsolidus PT for the plag spinel lherzolite assemblage are not well constrained, but are about 3 kb and 700-800 C, consistent with the conductive geotherm inferred from igneous PT estimates. Thus, melts began to cool and crystallize at depths > 15 km. Impregnated and residual peridotites in our core appear undeformed. Though they may have a strong olivine LPO, there are few shape fabrics. Instead skeletal, interstitial pyroxene and spinel extend for mm in 2D and 3D. Core from most sites includes high T mylonitic shear zones (mainly impregnated peridotite) and low T fault gouge. Shear zones and faults are not all parallel; numerous, cross-cutting planes of localized deformation formed at >1000 C to <100 C, from >15 km to the seafloor. These accommodated subsolidus deformation during corner flow and exhumation of peridotites and high P igneous rocks, in keeping with previous inferences that the thermal boundary layer beneath the MAR extends to about 20 km. Penetrative deformation of blocks between shear zones and faults was minor. Localization of deformation at high temperature may have been facilitated by the presence of melt.

What is the truth? An application of the Extended Parallel Process Model to televised truth® ads.

PubMed

Lavoie, Nicole R; Quick, Brian L

2013-01-01

The purpose of this study was to analyze television ads in the truth® campaign using the Extended Parallel Process Model (EPPM) as a framework. Among the ads (n = 86) analyzed, results revealed a heavy reliance on severity messages, modest attention to susceptibility messages, and no inclusion of recommended response messages in the form of self-efficacy and response efficacy. The reliance on emphasizing the health threat, without incorporating recommended response messages, is discussed with respect to the likelihood of galvanizing maladaptive responses such as psychological reactance, denial, and defensive avoidance resulting from exposure to these ads. Additionally, the unintended outcomes for secondary audiences including but not limited to stigma are considered. Implications and suggestions for practitioners and theorists are explored.

X-ray imaging crystal spectrometer for extended X-ray sources

DOEpatents

Bitter, Manfred L.; Fraenkel, Ben; Gorman, James L.; Hill, Kenneth W.; Roquemore, A. Lane; Stodiek, Wolfgang; von Goeler, Schweickhard E.

2001-01-01

Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokomak fusion experiment to provide spatially and temporally resolved data on plasma parameters using the imaging properties for Bragg angles near 45. For a Bragg angle of 45.degree., the spherical crystal focuses a bundle of near parallel X-rays (the cross section of which is determined by the cross section of the crystal) from the plasma to a point on a detector, with parallel rays inclined to the main plain of diffraction focused to different points on the detector. Thus, it is possible to radially image the plasma X-ray emission in different wavelengths simultaneously with a single crystal.

Spectral tuning of near-field radiative heat transfer by graphene-covered metasurfaces

NASA Astrophysics Data System (ADS)

Zheng, Zhiheng; Wang, Ao; Xuan, Yimin

2018-03-01

When two gratings are respectively covered by a layer of graphene sheet, the near-field radiative heat transfer between two parallel gratings made of silica (SiO2) could be greatly improved. As the material properties of doped silicon (n-type doping concentration is 1020 cm-3, marked as Si-20) and SiO2 differ greatly, we theoretically investigate the near-field radiative heat transfer between two parallel graphene-covered gratings made of Si-20 to explore some different phenomena, especially for modulating the spectral properties. The radiative heat flux between two parallel bulks made of Si-20 can be enhanced by using gratings instead of bulks. When the two gratings are respectively covered by a layer of graphene sheet, the radiative heat flux between two gratings made of Si-20 can be further enhanced. By tuning graphene chemical potential μ and grating filling factor f, due to the interaction between surface plasmon polaritons (SPPs) of graphene sheets and grating structures, the spectral properties of the radiative heat flux between two parallel graphene-covered gratings can be effectively regulated. This work will develop and supplement the effects of materials on the near-field radiative heat transfer for this kind of system configuration, paving a way to modulate the spectral properties of near-field radiative heat transfer.

Deformation along the leading edge of the Maiella thrust sheet in central Italy

NASA Astrophysics Data System (ADS)

Aydin, Atilla; Antonellini, Marco; Tondi, Emanuele; Agosta, Fabrizio

2010-09-01

The eastern forelimb of the Maiella anticline above the leading edge of the underlying thrust displays a complex system of fractures, faults and a series of kink bands in the Cretaceous platform carbonates. The kink bands have steep limbs, display top-to-the-east shear, parallel to the overall transport direction, and are brecciated and faulted. A system of pervasive normal faults, trending sub-parallel to the strike of the mechanical layers, accommodates local extension generated by flexural slip. Two sets of strike-slip faults exist: one is left-lateral at a high angle to the main Maiella thrust; the other is right-lateral, intersecting the first set at an acute angle. The normal and strike-slip faults were formed by shearing across bed-parallel, strike-, and dip-parallel pressure solution seams and associated splays; the thrust faults follow the tilted mechanical layers along the steeper limb of the kink bands. The three pervasive, mutually-orthogonal pressure solution seams are pre-tilting. One set of low-angle normal faults, the oldest set in the area, is also pre-tilting. All other fault/fold structures appear to show signs of overlapping periods of activity accounting for the complex tri-shear-like deformation that developed as the front evolved during the Oligocene-Pliocene Apennine orogeny.

Simulation of dispersion in layered coastal aquifer systems

USGS Publications Warehouse

Reilly, T.E.

1990-01-01

A density-dependent solute-transport formulation is used to examine ground-water flow in layered coastal aquifers. The numerical experiments indicate that although the transition zone may be thought of as an impermeable 'sharp' interface with freshwater flow parallel to the transition zone in homogeneous aquifers, this is not the case for layered systems. Freshwater can discharge through the transition zone in the confining units. Further, for the best simulation of layered coastal aquifer systems, either a flow-direction-dependent dispersion formulation is required, or the dispersivities must change spatially to reflect the tight thin confining unit. ?? 1990.

Progress report on PIXIE3D, a fully implicit 3D extended MHD solver

NASA Astrophysics Data System (ADS)

Chacon, Luis

2008-11-01

Recently, invited talk at DPP07 an optimal, massively parallel implicit algorithm for 3D resistive magnetohydrodynamics (PIXIE3D) was demonstrated. Excellent algorithmic and parallel results were obtained with up to 4096 processors and 138 million unknowns. While this is a remarkable result, further developments are still needed for PIXIE3D to become a 3D extended MHD production code in general geometries. In this poster, we present an update on the status of PIXIE3D on several fronts. On the physics side, we will describe our progress towards the full Braginskii model, including: electron Hall terms, anisotropic heat conduction, and gyroviscous corrections. Algorithmically, we will discuss progress towards a robust, optimal, nonlinear solver for arbitrary geometries, including preconditioning for the new physical effects described, the implementation of a coarse processor-grid solver (to maintain optimal algorithmic performance for an arbitrarily large number of processors in massively parallel computations), and of a multiblock capability to deal with complicated geometries. L. Chac'on, Phys. Plasmas 15, 056103 (2008);

Improving parallel I/O autotuning with performance modeling

DOE PAGES

Behzad, Babak; Byna, Surendra; Wild, Stefan M.; ...

2014-01-01

Various layers of the parallel I/O subsystem offer tunable parameters for improving I/O performance on large-scale computers. However, searching through a large parameter space is challenging. We are working towards an autotuning framework for determining the parallel I/O parameters that can achieve good I/O performance for different data write patterns. In this paper, we characterize parallel I/O and discuss the development of predictive models for use in effectively reducing the parameter space. Furthermore, applying our technique on tuning an I/O kernel derived from a large-scale simulation code shows that the search time can be reduced from 12 hours to 2more » hours, while achieving 54X I/O performance speedup.« less

Carbon nanotube nanoelectrode arrays

DOEpatents

Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

2008-11-18

The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

Magnetothermoelectric properties of layered structures for ion impurity scattering

NASA Astrophysics Data System (ADS)

Figarova, S. R.; Huseynov, H. I.; Figarov, V. R.

2018-05-01

In the paper, longitudinal and transverse thermoelectric powers are considered in a magnetic field parallel to the layer plane for scattering of charge carriers by weakly screened impurity ions. Based on the semiclassical approximation, it is obtained that, depending on the position of the Fermi level relative to the miniband top and superlattice period, the thermoelectric power can change sign and amplify.

Tunable Patch Antennas Using Microelectromechanical Systems

DTIC Science & Technology

2011-05-11

Figure 28, was selected as most suitable to this application. MetalMUMPs is a surface micromachining process with polysilicon , silicon nitride, nickel...yields. MEMS Variable Capacitor Design The MEMS capacitors reported here were an original design that features nickel and polysilicon layers as...the movable plates of a variable parallel plate capacitor. The polysilicon layer was embedded in silicon nitride for electrical isolation and suspended

Parallel odor processing by mitral and middle tufted cells in the olfactory bulb.

PubMed

Cavarretta, Francesco; Burton, Shawn D; Igarashi, Kei M; Shepherd, Gordon M; Hines, Michael L; Migliore, Michele

2018-05-16

The olfactory bulb (OB) transforms sensory input into spatially and temporally organized patterns of activity in principal mitral (MC) and middle tufted (mTC) cells. Thus far, the mechanisms underlying odor representations in the OB have been mainly investigated in MCs. However, experimental findings suggest that MC and mTC may encode parallel and complementary odor representations. We have analyzed the functional roles of these pathways by using a morphologically and physiologically realistic three-dimensional model to explore the MC and mTC microcircuits in the glomerular layer and deeper plexiform layer. The model makes several predictions. MCs and mTCs are controlled by similar computations in the glomerular layer but are differentially modulated in deeper layers. The intrinsic properties of mTCs promote their synchronization through a common granule cell input. Finally, the MC and mTC pathways can be coordinated through the deep short-axon cells in providing input to the olfactory cortex. The results suggest how these mechanisms can dynamically select the functional network connectivity to create the overall output of the OB and promote the dynamic synchronization of glomerular units for any given odor stimulus.

[Development and evaluation of the medical imaging distribution system with dynamic web application and clustering technology].

PubMed

Yokohama, Noriya; Tsuchimoto, Tadashi; Oishi, Masamichi; Itou, Katsuya

2007-01-20

It has been noted that the downtime of medical informatics systems is often long. Many systems encounter downtimes of hours or even days, which can have a critical effect on daily operations. Such systems remain especially weak in the areas of database and medical imaging data. The scheme design shows the three-layer architecture of the system: application, database, and storage layers. The application layer uses the DICOM protocol (Digital Imaging and Communication in Medicine) and HTTP (Hyper Text Transport Protocol) with AJAX (Asynchronous JavaScript+XML). The database is designed to decentralize in parallel using cluster technology. Consequently, restoration of the database can be done not only with ease but also with improved retrieval speed. In the storage layer, a network RAID (Redundant Array of Independent Disks) system, it is possible to construct exabyte-scale parallel file systems that exploit storage spread. Development and evaluation of the test-bed has been successful in medical information data backup and recovery in a network environment. This paper presents a schematic design of the new medical informatics system that can be accommodated from a recovery and the dynamic Web application for medical imaging distribution using AJAX.

Abdominal muscle and epipubic bone function during locomotion in Australian possums: insights to basal mammalian conditions and Eutherian-like tendencies in Trichosurus.

PubMed

Reilly, Stephen M; McElroy, Eric J; White, Thomas D; Biknevicius, Audrone R; Bennett, Michael B

2010-04-01

Mammals have four hypaxial muscle layers that wrap around the abdomen between the pelvis, ribcage, and spine. However, the marsupials have epipubic bones extending anteriorly into the ventral hypaxial layers with two additional muscles extending to the ventral midline and femur. Comparisons of South American marsupials to basal eutherians have shown that all of the abdominal hypaxials are active bilaterally in resting ventilation. However, during locomotion marsupials employ an asymmetrical pattern of activity as the hypaxial muscles form a crosscouplet linkage that uses the epipubic bone as a lever to provide long-axis support of the body between diagonal limb couplets during each step. In basal eutherians, this system shifts off the femur and epipubic bones (which are lost) resulting in a shoulder to pelvis linkage associated with shifts in both the positions and activity patterns of the pectineus and rectus abdominis muscles during locomotion. In this study, we present data on hypaxial function in two species (Pseudocheirus peregrinus and Trichosurus vulpecula) representing the two major radiations of possums in Australia: the Pseudocheiridae (within the Petauroidea) and the Phalangeridae. Patterns of gait, motor activity, and morphology in these two Australian species were compared with previous work to examine the generality of 1) the crosscouplet lever system as the basal condition for the Marsupialia and 2) several traits hypothesized to be common to all mammals (hypaxial tonus during resting ventilation, ventilation to step synchrony during locomotion, and bilateral transversus abdominis activity during locomotor expiration). Our results validate the presence of the crosscouplet pattern and basic epipubic bone lever system in Australian possums and confirm the generality of basal mammalian patterns. However, several novelties discovered in Trichosurus, reveal that it exhibits an evolutionary transition to intermediate eutherian-like morphological and motor patterns paralleling many other unique features of this species. (c) 2009 Wiley-Liss, Inc.

Differential encoding of spatial information among retinal on cone bipolar cells

PubMed Central

Purgert, Robert J.

2015-01-01

The retina is the first stage of visual processing. It encodes elemental features of visual scenes. Distinct cone bipolar cells provide the substrate for this to occur. They encode visual information, such as color and luminance, a principle known as parallel processing. Few studies have directly examined whether different forms of spatial information are processed in parallel among cone bipolar cells. To address this issue, we examined the spatial information encoded by mouse ON cone bipolar cells, the subpopulation excited by increments in illumination. Two types of spatial processing were identified. We found that ON cone bipolar cells with axons ramifying in the central inner plexiform layer were tuned to preferentially encode small stimuli. By contrast, ON cone bipolar cells with axons ramifying in the proximal inner plexiform layer, nearest the ganglion cell layer, were tuned to encode both small and large stimuli. This dichotomy in spatial tuning is attributable to amacrine cells providing stronger inhibition to central ON cone bipolar cells compared with proximal ON cone bipolar cells. Furthermore, background illumination altered this difference in spatial tuning. It became less pronounced in bright light, as amacrine cell-driven inhibition became pervasive among all ON cone bipolar cells. These results suggest that differential amacrine cell input determined the distinct spatial encoding properties among ON cone bipolar cells. These findings enhance the known parallel processing capacity of the retina. PMID:26203104

Learning, memory, and the role of neural network architecture.

PubMed

Hermundstad, Ann M; Brown, Kevin S; Bassett, Danielle S; Carlson, Jean M

2011-06-01

The performance of information processing systems, from artificial neural networks to natural neuronal ensembles, depends heavily on the underlying system architecture. In this study, we compare the performance of parallel and layered network architectures during sequential tasks that require both acquisition and retention of information, thereby identifying tradeoffs between learning and memory processes. During the task of supervised, sequential function approximation, networks produce and adapt representations of external information. Performance is evaluated by statistically analyzing the error in these representations while varying the initial network state, the structure of the external information, and the time given to learn the information. We link performance to complexity in network architecture by characterizing local error landscape curvature. We find that variations in error landscape structure give rise to tradeoffs in performance; these include the ability of the network to maximize accuracy versus minimize inaccuracy and produce specific versus generalizable representations of information. Parallel networks generate smooth error landscapes with deep, narrow minima, enabling them to find highly specific representations given sufficient time. While accurate, however, these representations are difficult to generalize. In contrast, layered networks generate rough error landscapes with a variety of local minima, allowing them to quickly find coarse representations. Although less accurate, these representations are easily adaptable. The presence of measurable performance tradeoffs in both layered and parallel networks has implications for understanding the behavior of a wide variety of natural and artificial learning systems.

Solution-phase parallel synthesis of aryloxyimino amides via a novel multicomponent reaction among aromatic (Z)-chlorooximes, isocyanides, and electron-deficient phenols.

PubMed

Mercalli, Valentina; Giustiniano, Mariateresa; Del Grosso, Erika; Varese, Monica; Cassese, Hilde; Massarotti, Alberto; Novellino, Ettore; Tron, Gian Cesare

2014-11-10

A library of 41 aryloxyimino amides was prepared via solution phase parallel synthesis by extending the multicomponent reaction of (Z)-chlorooximes and isocyanides to the use of electron-deficient phenols. The resulting aryloxyiminoamide derivatives can be used as intermediates for the synthesis of benzo[d]isoxazole-3-carboxamides, dramatically reducing the number of synthetic steps required by other methods reported in literature.

Sea shell solar collector

DOEpatents

Rabl, Ari

1976-01-01

A device is provided for the collection and concentration of solar radiant energy including a longitudinally extending structure having a wall for directing radiant energy. The wall is parabolic with its focus along a line parallel to an extreme ray of the sun at one solstice and with its axis along a line parallel to an extreme ray of the sun at the other solstice. An energy absorber is positioned to receive the solar energy thereby collected.

Electron parallel closures for various ion charge numbers

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

Ji, Jeong-Young, E-mail: j.ji@usu.edu; Held, Eric D.; Kim, Sang-Kyeun

2016-03-15

Electron parallel closures for the ion charge number Z = 1 [J.-Y. Ji and E. D. Held, Phys. Plasmas 21, 122116 (2014)] are extended for 1 ≤ Z ≤ 10. Parameters are computed for various Z with the same form of the Z = 1 kernels adopted. The parameters are smoothly varying in Z and hence can be used to interpolate parameters and closures for noninteger, effective ion charge numbers.

Forecasting Three-Month Outcomes in a Laboratory School Comparison of Mixed Amphetamine Salts Extended Release (Adderall XR) and Atomoxetine (Strattera) in School-Aged Children with ADHD

ERIC Educational Resources Information Center

Faraone, Stephen V.; Wigal, Sharon B.; Hodgkins, Paul

2007-01-01

Objective: Compare observed and forecasted efficacy of mixed amphetamine salts extended release (MAS-XR; Adderall) with atomoxetine (Strattera) in ADHD children. Method: The authors analyze data from a randomized, double-blind, multicenter, parallel-group, forced-dose-escalation laboratory school study of children ages 6 to 12 with ADHD combined…

On the dimensionally correct kinetic theory of turbulence for parallel propagation

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

Gaelzer, R., E-mail: rudi.gaelzer@ufrgs.br, E-mail: yoonp@umd.edu, E-mail: 007gasun@khu.ac.kr, E-mail: luiz.ziebell@ufrgs.br; Ziebell, L. F., E-mail: rudi.gaelzer@ufrgs.br, E-mail: yoonp@umd.edu, E-mail: 007gasun@khu.ac.kr, E-mail: luiz.ziebell@ufrgs.br; Yoon, P. H., E-mail: rudi.gaelzer@ufrgs.br, E-mail: yoonp@umd.edu, E-mail: 007gasun@khu.ac.kr, E-mail: luiz.ziebell@ufrgs.br

2015-03-15

Yoon and Fang [Phys. Plasmas 15, 122312 (2008)] formulated a second-order nonlinear kinetic theory that describes the turbulence propagating in directions parallel/anti-parallel to the ambient magnetic field. Their theory also includes discrete-particle effects, or the effects due to spontaneously emitted thermal fluctuations. However, terms associated with the spontaneous fluctuations in particle and wave kinetic equations in their theory contain proper dimensionality only for an artificial one-dimensional situation. The present paper extends the analysis and re-derives the dimensionally correct kinetic equations for three-dimensional case. The new formalism properly describes the effects of spontaneous fluctuations emitted in three-dimensional space, while the collectivelymore » emitted turbulence propagates predominantly in directions parallel/anti-parallel to the ambient magnetic field. As a first step, the present investigation focuses on linear wave-particle interaction terms only. A subsequent paper will include the dimensionally correct nonlinear wave-particle interaction terms.« less

Structure development in melt processing isotactic polypropylene, polypropylene blends/compounds and dynamically vulcanized polyolefin TPEs

NASA Astrophysics Data System (ADS)

Yu, Yishan

The influence of various fillers, nucleating agents and ethylene propylene diene terpolymer (EPDM) additive on crystalline modification (alpha-, beta- and smectic forms) and crystalline orientation of polypropylene in die extrudates, melt spun filaments, thick rods, blow molded bottles and injection molded parts of isotactic polypropylene (PP), its blends/compounds and dynamically vulcanized polypropylene thermoplastic elastomers (TPEs) were experimentally studied under a range of cooling and processing conditions. The phenomena of crystallization, polymorphism and orientation in processing of both thin and thick samples (filaments, rods, bottles and injection molded parts) were simulated through transport laws incorporating polymer crystallization kinetics. Continuous cooling transformation (CCT) curves for the various material systems investigated were developed under quiescent and uniaxial stress conditions. We applied experimental data on polymorphism of thin sections to predict crystalline structure variation in thick parts. The predictions were consistent with experiments. For filaments, the polypropylene crystalline orientation-spinline stress relationship is generally similar for the neat PP, blends/compounds and TPEs. However, the blends and TPEs have much lower birefringence apparently due to a lack of orientation in the rubber phase. It was shown that the polypropylene contribution to the birefringence for the neat PP and its blends is the same at the same spinline stress. For bottles, the inflation pressures used have little effect on orientation of either polypropylene crystals or disc-shaped talc filler. The talc discs are highly oriented parallel to the bottle surface. For the bottles without talc, the orientation of polypropylene crystallographic axes are low. The polypropylene crystallographic b-axes in the talc filled bottles are more highly oriented. For injection molded parts, it was found that a low orientation layer exists between the part surface and an intermediate highly oriented layer in the parts of neat PP and its blends/compounds. The thickness of this layer increases as the injection pressure decreases. This layer was not formed in the TPE parts. This would seem to be associated with the TPEs exhibiting a yield stress in shear flow and not exhibiting fountain flow in mold filling. For all parts studied, the orientation characteristics of polypropylene crystallographic axes in the highly oriented layer are similar from sample to sample. The strong orientation of the c-axis parallel to the machine direction and the b-axis perpendicular to the machine direction are observed in the highly oriented layer. The talc discs in both the highly oriented layer and the intermediate position are highly oriented parallel to the part face due to melt flow. At intermediate position in the talc-filled parts, the polypropylene crystallographic (040) planes prefer to align themselves parallel to the part surface but are not so well oriented when the talc is absent.

Modification in drag of turbulent boundary layers resulting from manipulation of large-scale structures

NASA Technical Reports Server (NTRS)

Corke, T. C.; Guezennec, Y.; Nagib, H. M.

1981-01-01

The effects of placing a parallel-plate turbulence manipulator in a boundary layer are documented through flow visualization and hot wire measurements. The boundary layer manipulator was designed to manage the large scale structures of turbulence leading to a reduction in surface drag. The differences in the turbulent structure of the boundary layer are summarized to demonstrate differences in various flow properties. The manipulator inhibited the intermittent large scale structure of the turbulent boundary layer for at least 70 boundary layer thicknesses downstream. With the removal of the large scale, the streamwise turbulence intensity levels near the wall were reduced. The downstream distribution of the skin friction was also altered by the introduction of the manipulator.

Frictional Magneto-Coulomb Drag in Graphene Double-Layer Heterostructures.

PubMed

Liu, Xiaomeng; Wang, Lei; Fong, Kin Chung; Gao, Yuanda; Maher, Patrick; Watanabe, Kenji; Taniguchi, Takashi; Hone, James; Dean, Cory; Kim, Philip

2017-08-04

Coulomb interaction between two closely spaced parallel layers of conductors can generate the frictional drag effect by interlayer Coulomb scattering. Employing graphene double layers separated by few-layer hexagonal boron nitride, we investigate density tunable magneto- and Hall drag under strong magnetic fields. The observed large magnetodrag and Hall-drag signals can be related with Laudau level filling status of the drive and drag layers. We find that the sign and magnitude of the drag resistivity tensor can be quantitatively correlated to the variation of magnetoresistivity tensors in the drive and drag layers, confirming a theoretical formula for magnetodrag in the quantum Hall regime. The observed weak temperature dependence and ∼B^{2} dependence of the magnetodrag are qualitatively explained by Coulomb scattering phase-space argument.

The role of nonlinear critical layers in boundary layer transition

NASA Technical Reports Server (NTRS)

Goldstein, M.E.

1995-01-01

Asymptotic methods are used to describe the nonlinear self-interaction between pairs of oblique instability modes that eventually develops when initially linear spatially growing instability waves evolve downstream in nominally two-dimensional laminar boundary layers. The first nonlinear reaction takes place locally within a so-called 'critical layer', with the flow outside this layer consisting of a locally parallel mean flow plus a pair of oblique instability waves - which may or may not be accompanied by an associated plane wave. The amplitudes of these waves, which are completely determined by nonlinear effects within the critical layer, satisfy either a single integro-differential equation or a pair of integro-differential equations with quadratic to quartic-type nonlinearities. The physical implications of these equations are discussed.

Extensive ionic partitioning in interfaces that membranous and biomimetic surfaces form with electrolytes: Antitheses of the gold-electrolyte interface

NASA Astrophysics Data System (ADS)

Chilcott, Terry; Guo, Chuan; Coster, Hans

2013-04-01

Maxwell-Wagner modeling of electrical impedance measurements of tetradecane-electrolyte systems yielded three interfacial layers between the tetradecane layer and the bulk electrolytes of concentration ranging from 1-300 mM KCl whereas the gold-electrolyte system yielded only one layer. The conductivity and thickness for the surface layer were orders of magnitude different from that expected for the Gouy-Chapman layer and did not reflect dependencies of the Debye length on concentration. Conductivity values for the three layers were less than those of the bulk electrolyte but exhibited a dependency on concentration similar to that expected for the bulk. Thickness values for the layers indicate an interface extending ~106 Å into the bulk electrolyte, which contrasts with the gold-electrolyte interface that extended only 20-30 Å into the bulk. Maxwell-Wagner characterizations of both interfaces were consistent with spatial distributions of ionic partitioning arising from the Born energy as determined by the dielectric properties of the substrates and electrolyte. The distributions for the membranous and silicon interfaces were similar but the antitheses of that for the gold interface.

Haze Production in Pluto's Atmosphere

NASA Astrophysics Data System (ADS)

Summers, M. E.; Gladstone, R.; Stern, A.; Ennico Smith, K.; Greathouse, T.; Hinson, D. P.; Kammer, J.; Linscott, I.; Olkin, C.; Parker, A. H.; Parker, J. W.; Retherford, K. D.; Schindhelm, E.; Singer, K. N.; Steffl, A.; Strobel, D. F.; Tsang, C.; Tyler, G. L.; Versteeg, M. H.; Weaver, H. A., Jr.; Wong, M. L.; Woods, W. W.; Yung, Y. L.; Young, L. A.; Lisse, C. M.; Lavvas, P.; Renaud, J.; Ewell, M.; Jacobs, A. D.

2015-12-01

One of the most visible manifestations of Pluto's atmosphere observed from the New Horizons spacecraft during the flyby in July 2015 was a global haze layer extending to an altitude ~150 km above Pluto's surface. The haze layer exhibits a significant hemispheric asymmetry and what appears to be layered and/or wave like features. Stellar observations since 1989 have suggested the existence of a haze layer in Pluto's lower atmosphere to explain features in occultation light curves. A haze layer is also expected from photochemical models of Pluto's methane atmosphere wherein hydrocarbons and are produced at altitudes above 100 km altitude, mix downwards, and condense at the low atmospheric temperatures near the surface. However, the observed haze layer(s) extends much higher where the atmospheric temperature is too high for condensation. In this paper we will discuss the production and condensation of photochemical products, and evaluate the possibility that nucleation begins in the ionosphere by a mechanism similar to that proposed for the atmosphere of Titan, where electron attachments initiates a sequence of ion-molecular reactions that ultimately produce aerosol "tholins" that settle downward and coat the surface.

Metaporous layer to overcome the thickness constraint for broadband sound absorption

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

Yang, Jieun; Lee, Joong Seok; Kim, Yoon Young, E-mail: yykim@snu.ac.kr

The sound absorption of a porous layer is affected by its thickness, especially in a low-frequency range. If a hard-backed porous layer contains periodical arrangements of rigid partitions that are coordinated parallel and perpendicular to the direction of incoming sound waves, the lower bound of the effective sound absorption can be lowered much more and the overall absorption performance enhanced. The consequence of rigid partitioning in a porous layer is to make the first thickness resonance mode in the layer appear at much lower frequencies compared to that in the original homogeneous porous layer with the same thickness. Moreover, appropriatemore » partitioning yields multiple thickness resonances with higher absorption peaks through impedance matching. The physics of the partitioned porous layer, or the metaporous layer, is theoretically investigated in this study.« less

Heating element support clip

DOEpatents

Sawyer, William C.

1995-01-01

An apparatus for supporting a heating element in a channel formed in a heater base is disclosed. A preferred embodiment includes a substantially U-shaped tantalum member. The U-shape is characterized by two substantially parallel portions of tantalum that each have an end connected to opposite ends of a base portion of tantalum. The parallel portions are each substantially perpendicular to the base portion and spaced apart a distance not larger than a width of the channel and not smaller than a width of a graphite heating element. The parallel portions each have a hole therein, and the centers of the holes define an axis that is substantially parallel to the base portion. An aluminum oxide ceramic retaining pin extends through the holes in the parallel portions and into a hole in a wall of the channel to retain the U-shaped member in the channel and to support the graphite heating element. The graphite heating element is confined by the parallel portions of tantalum, the base portion of tantalum, and the retaining pin. A tantalum tube surrounds the retaining pin between the parallel portions of tantalum.

Heating element support clip

DOEpatents

Sawyer, W.C.

1995-08-15

An apparatus for supporting a heating element in a channel formed in a heater base is disclosed. A preferred embodiment includes a substantially U-shaped tantalum member. The U-shape is characterized by two substantially parallel portions of tantalum that each have an end connected to opposite ends of a base portion of tantalum. The parallel portions are each substantially perpendicular to the base portion and spaced apart a distance not larger than a width of the channel and not smaller than a width of a graphite heating element. The parallel portions each have a hole therein, and the centers of the holes define an axis that is substantially parallel to the base portion. An aluminum oxide ceramic retaining pin extends through the holes in the parallel portions and into a hole in a wall of the channel to retain the U-shaped member in the channel and to support the graphite heating element. The graphite heating element is confined by the parallel portions of tantalum, the base portion of tantalum, and the retaining pin. A tantalum tube surrounds the retaining pin between the parallel portions of tantalum. 6 figs.

Self-Assembled Films of Dendrimers and Metallophthalocyanines as FET-Based Glucose Biosensors

PubMed Central

Vieira, Nirton C.S.; Figueiredo, Alessandra; de Queiroz, Alvaro A.A.; Zucolotto, Valtencir; Guimarães, Francisco E.G.

2011-01-01

Separative extended gate field effect transistor (SEGFET) type devices have been used as an ion sensor or biosensor as an alternative to traditional ion sensitive field effect transistors (ISFETs) due to their robustness, ease of fabrication, low cost and possibility of FET isolation from the chemical environment. The layer-by-layer technique allows the combination of different materials with suitable properties for enzyme immobilization on simple platforms such as the extended gate of SEGFET devices enabling the fabrication of biosensors. Here, glucose biosensors based on dendrimers and metallophthalocyanines (MPcs) in the form of layer-by-layer (LbL) films, assembled on indium tin oxide (ITO) as separative extended gate material, has been produced. NH3+ groups in the dendrimer allow electrostatic interactions or covalent bonds with the enzyme (glucose oxidase). Relevant parameters such as optimum pH, buffer concentration and presence of serum bovine albumin (BSA) in the immobilization process were analyzed. The relationship between the output voltage and glucose concentration shows that upon detection of a specific analyte, the sub-products of the enzymatic reaction change the pH locally, affecting the output signal of the FET transducer. In addition, dendritic layers offer a nanoporous environment, which may be permeable to H+ ions, improving the sensibility as modified electrodes for glucose biosensing. PMID:22163704

Spin-orbit torque induced magnetization switching in heavy metal/ferromagnet multilayers with bilayer of heavy metals

NASA Astrophysics Data System (ADS)

Bekele, Zelalem Abebe; Meng, Kangkang; Zhao, Bing; Wu, Yong; Miao, Jun; Xu, Xiaoguang; Jiang, Yong

2017-08-01

Symmetry breaking provides new insight into the physics of spin-orbit torque (SOT) and the switching without a magnetic field could lead to significant impact. In this work, we demonstrate the robust zero-field SOT switching of a perpendicular ferromagnet (FM) layer where the symmetry is broken by a bilayer of heavy metals (HMs) with the strong spin-orbit coupling (SOC). We observed the change of coercivity value by 31% after inserting Co2FeAl in the multilayer structure. These two HM layers (Ta and Pt) are used to strengthen the SOC by linear combination. With different angles between the magnetization and the current (i.e. parallel and anti-parallel), the structures show different switching behaviors such as clockwise or counterclockwise.

Anisotropic Josephson-vortex dynamics in layered organic superconductors

NASA Astrophysics Data System (ADS)

Yasuzuka, S.; Uji, S.; Satsukawa, H.; Kimata, M.; Terashima, T.; Koga, H.; Yamamura, Y.; Saito, K.; Akutsu, H.; Yamada, J.

2010-06-01

To study the anisotropic Josephson-vortex dynamics in the d-wave superconductors, the interplane resistance has been measured on layered organic superconductors κ-(ET)2Cu(NCS)2 and β-(BDA-TTP)2SbF6 under magnetic fields precisely parallel to the conducting planes. For κ-(ET)2Cu(NCS)2, in-plane angular dependence of the Josephson-vortex flow resistance is mainly described by the fourfold symmetry and dip structures appear when the magnetic field is applied parallel to the b- and c-axes. The obtained results have a relation to the d-wave superconducting gap symmetry. However, the absence of in-plane fourfold anisotropy was found for β-(BDA-TTP)2SbF6. The different anisotropic behavior is discussed in terms of the interlayer coupling strength.

Molecular dynamics simulations of pyrrolidinium and imidazolium ionic liquids at graphene interfaces.

PubMed

Begić, Srđan; Jónsson, Erlendur; Chen, Fangfang; Forsyth, Maria

2017-11-15

Understanding the electrode-electrolyte interface is essential in the battery research as the ion transport and ion structures at the interface most likely affect the performance of a battery. Here we investigate interfacial structures of three ionic liquids: 1-ethyl-3-methylimidazolium dicyanamide ([C 2 mim][dca]), 1-butyl-3-methylimidazolium dicyanamide ([C 4 mim][dca]) and N-butyl-N-methylpyrrolidinium dicyanamide ([C 4 myr][dca]) at a charged and uncharged graphene interface using molecular dynamics simulations. We find that these ionic liquids (ILs) behave differently both in the bulk phase and near a graphene interface and we find that this difference is apparent in all types of analyses performed here. First, a partial density analysis in the direction perpendicular to the surface of the electrodes, which, in the cases near a negatively charged graphene, reveals that the pyrrolidinium system is generally more layered than the imidazolium systems. Second, a 2D topographic structure analysis of the IL species in the inner layer near a negatively charged graphene surface, which reveals that the pyrrolidinium system exhibits a quasi-hexagonal surface configuration of the cations, while the imidazolium systems show linearly arranged groups of cations. Third, a 3D orientation-preference analysis of cation rings near the negative graphene electrode, which shows that the pyrrolidinium rings prefer to lie parallel to the electrode surface while the imidazolium rings prefer to stand on the electrode surface at high tilt angles. Extending the imidazolium alkyl chain was found to reduce the number of imidazoliums that can link up into linearly arranged groups in the inner layer 2D structures. Our results support earlier experimental findings and indicate that the interfacial nanostructures may have a significant influence on the electrochemical performance of IL-based batteries.

Gas turbine bucket cooling circuit and related process

DOEpatents

Lewis, Doyle C.; Barb, Kevin Joseph

2002-01-01

A turbine bucket includes an airfoil portion having leading and trailing edges; at least one radially extending cooling passage within the airfoil portion, the airfoil portion joined to a platform at a radially inner end of the airfoil portion; a dovetail mounting portion enclosing a cooling medium supply passage; and, a crossover passage in fluid communication with the cooling medium supply passage and with at least one radially extending cooling passage, the crossover passage having a portion extending along and substantially parallel to an underside surface of the platform.

A mechanism for efficient debugging of parallel programs

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

Miller, B.P.; Choi, J.D.

1988-01-01

This paper addresses the design and implementation of an integrated debugging system for parallel programs running on shared memory multi-processors (SMMP). The authors describe the use of flowback analysis to provide information on causal relationships between events in a program's execution without re-executing the program for debugging. The authors introduce a mechanism called incremental tracing that, by using semantic analyses of the debugged program, makes the flowback analysis practical with only a small amount of trace generated during execution. The extend flowback analysis to apply to parallel programs and describe a method to detect race conditions in the interactions ofmore » the co-operating processes.« less

Scalable and massively parallel Monte Carlo photon transport simulations for heterogeneous computing platforms

NASA Astrophysics Data System (ADS)

Yu, Leiming; Nina-Paravecino, Fanny; Kaeli, David; Fang, Qianqian

2018-01-01

We present a highly scalable Monte Carlo (MC) three-dimensional photon transport simulation platform designed for heterogeneous computing systems. Through the development of a massively parallel MC algorithm using the Open Computing Language framework, this research extends our existing graphics processing unit (GPU)-accelerated MC technique to a highly scalable vendor-independent heterogeneous computing environment, achieving significantly improved performance and software portability. A number of parallel computing techniques are investigated to achieve portable performance over a wide range of computing hardware. Furthermore, multiple thread-level and device-level load-balancing strategies are developed to obtain efficient simulations using multiple central processing units and GPUs.

Stability of parallel electroosmotic flow subject to an axial modulated electric field

NASA Astrophysics Data System (ADS)

Suresh, Vinod; Homsy, George

2001-11-01

The stability of parallel electroosmotic flow in a micro-channel subjected to an AC electric field is studied. A spatially uniform time harmonic electric field is applied along the length of a two-dimensional micro-channel containing a dilute electrolytic solution, resulting in a time periodic parallel flow. The top and bottom walls of the channel are maintained at constant potential. The base state ion concentrations and double layer potential are determined using the Poisson-Boltzmann equation in the Debye-Hückel approximation. Experiments by other workers (Santiago et. al., unpublished) have shown that such a system can exhibit instabilities that take the form of mixing motion occurring in the bulk flow outside the double layer. It is shown that such instabilities can potentially result from the coupling of disturbances in the ion concentrations or electric potential to the base state velocity or ion concentrations, respectively. The stability boundary of the system is determined using Floquet theory and its dependence on the modulation frequency and amplitude of the axial electric field is studied.

Numerical aspects and implementation of a two-layer zonal wall model for LES of compressible turbulent flows on unstructured meshes

NASA Astrophysics Data System (ADS)

Park, George Ilhwan; Moin, Parviz

2016-01-01

This paper focuses on numerical and practical aspects associated with a parallel implementation of a two-layer zonal wall model for large-eddy simulation (LES) of compressible wall-bounded turbulent flows on unstructured meshes. A zonal wall model based on the solution of unsteady three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations on a separate near-wall grid is implemented in an unstructured, cell-centered finite-volume LES solver. The main challenge in its implementation is to couple two parallel, unstructured flow solvers for efficient boundary data communication and simultaneous time integrations. A coupling strategy with good load balancing and low processors underutilization is identified. Face mapping and interpolation procedures at the coupling interface are explained in detail. The method of manufactured solution is used for verifying the correct implementation of solver coupling, and parallel performance of the combined wall-modeled LES (WMLES) solver is investigated. The method has successfully been applied to several attached and separated flows, including a transitional flow over a flat plate and a separated flow over an airfoil at an angle of attack.

Multilayer perceptron architecture optimization using parallel computing techniques.

PubMed

Castro, Wilson; Oblitas, Jimy; Santa-Cruz, Roberto; Avila-George, Himer

2017-01-01

The objective of this research was to develop a methodology for optimizing multilayer-perceptron-type neural networks by evaluating the effects of three neural architecture parameters, namely, number of hidden layers (HL), neurons per hidden layer (NHL), and activation function type (AF), on the sum of squares error (SSE). The data for the study were obtained from quality parameters (physicochemical and microbiological) of milk samples. Architectures or combinations were organized in groups (G1, G2, and G3) generated upon interspersing one, two, and three layers. Within each group, the networks had three neurons in the input layer, six neurons in the output layer, three to twenty-seven NHL, and three AF (tan-sig, log-sig, and linear) types. The number of architectures was determined using three factorial-type experimental designs, which reached 63, 2 187, and 50 049 combinations for G1, G2 and G3, respectively. Using MATLAB 2015a, a logical sequence was designed and implemented for constructing, training, and evaluating multilayer-perceptron-type neural networks using parallel computing techniques. The results show that HL and NHL have a statistically relevant effect on SSE, and from two hidden layers, AF also has a significant effect; thus, both AF and NHL can be evaluated to determine the optimal combination per group. Moreover, in the three study groups, it is observed that there is an inverse relationship between the number of processors and the total optimization time.

Global stability analysis of axisymmetric boundary layer over a circular cylinder

NASA Astrophysics Data System (ADS)

Bhoraniya, Ramesh; Vinod, Narayanan

2018-05-01

This paper presents a linear global stability analysis of the incompressible axisymmetric boundary layer on a circular cylinder. The base flow is parallel to the axis of the cylinder at inflow boundary. The pressure gradient is zero in the streamwise direction. The base flow velocity profile is fully non-parallel and non-similar in nature. The boundary layer grows continuously in the spatial directions. Linearized Navier-Stokes (LNS) equations are derived for the disturbance flow quantities in the cylindrical polar coordinates. The LNS equations along with homogeneous boundary conditions forms a generalized eigenvalues problem. Since the base flow is axisymmetric, the disturbances are periodic in azimuthal direction. Chebyshev spectral collocation method and Arnoldi's iterative algorithm is used for the solution of the general eigenvalues problem. The global temporal modes are computed for the range of Reynolds numbers and different azimuthal wave numbers. The largest imaginary part of the computed eigenmodes is negative, and hence, the flow is temporally stable. The spatial structure of the eigenmodes shows that the disturbance amplitudes grow in size and magnitude while they are moving towards downstream. The global modes of axisymmetric boundary layer are more stable than that of 2D flat-plate boundary layer at low Reynolds number. However, at higher Reynolds number they approach 2D flat-plate boundary layer. Thus, the damping effect of transverse curvature is significant at low Reynolds number. The wave-like nature of the disturbance amplitudes is found in the streamwise direction for the least stable eigenmodes.

Multilayer perceptron architecture optimization using parallel computing techniques

PubMed Central

Castro, Wilson; Oblitas, Jimy; Santa-Cruz, Roberto; Avila-George, Himer

2017-01-01

The objective of this research was to develop a methodology for optimizing multilayer-perceptron-type neural networks by evaluating the effects of three neural architecture parameters, namely, number of hidden layers (HL), neurons per hidden layer (NHL), and activation function type (AF), on the sum of squares error (SSE). The data for the study were obtained from quality parameters (physicochemical and microbiological) of milk samples. Architectures or combinations were organized in groups (G1, G2, and G3) generated upon interspersing one, two, and three layers. Within each group, the networks had three neurons in the input layer, six neurons in the output layer, three to twenty-seven NHL, and three AF (tan-sig, log-sig, and linear) types. The number of architectures was determined using three factorial-type experimental designs, which reached 63, 2 187, and 50 049 combinations for G1, G2 and G3, respectively. Using MATLAB 2015a, a logical sequence was designed and implemented for constructing, training, and evaluating multilayer-perceptron-type neural networks using parallel computing techniques. The results show that HL and NHL have a statistically relevant effect on SSE, and from two hidden layers, AF also has a significant effect; thus, both AF and NHL can be evaluated to determine the optimal combination per group. Moreover, in the three study groups, it is observed that there is an inverse relationship between the number of processors and the total optimization time. PMID:29236744

Fabricating with crystalline Si to improve superconducting detector performance

NASA Astrophysics Data System (ADS)

Beyer, A. D.; Hollister, M. I.; Sayers, J.; Frez, C. F.; Day, P. K.; Golwala, S. R.

2017-05-01

We built and measured radio-frequency (RF) loss tangent, tan δ, evaluation structures using float-zone quality silicon-on-insulator (SOI) wafers with 5 μm thick device layers. Superconducting Nb components were fabricated on both sides of the SOI Si device layer. Our main goals were to develop a robust fabrication for using crystalline Si (c-Si) dielectric layers with superconducting Nb components in a wafer bonding process and to confirm that tan δ with c-Si dielectric layers was reduced at RF frequencies compared to devices fabricated with amorphous dielectrics, such as SiO2 and SixNy, where tan δ ∼ 10-3. Our primary test structure used a Nb coplanar waveguide (CPW) readout structure capacitively coupled to LC resonators, where the capacitors were defined as parallel-plate capacitors on both sides of a c-Si device layer using a wafer bonding process with benzocyclobutene (BCB) wafer bonding adhesive. Our control experiment, to determine the intrinsic tan δ in the SOI device layer without wafer bonding, also used Nb CPW readout coupled to LC resonators; however, the parallel-plate capacitors were fabricated on both sides of the Si device layer using a deep reactive ion etch (DRIE) to access the c-Si underside through the buried oxide and handle Si layers in the SOI wafers. We found that our wafer bonded devices demonstrated F· δ = (8 ± 2) × 10-5, where F is the filling fraction of two-level states (TLS). For the control experiment, F· δ = (2.0 ± 0.6) × 10-5, and we discuss what may be degrading the performance in the wafer bonded devices as compared to the control devices.

Pile construction

DOEpatents

Johnson, Alfred A.; Carleton, John T.

1978-05-02

A graphite-moderated, water-cooled nuclear reactor including graphite blocks disposed in transverse alternate layers, one set of alternate layers consisting of alternate full size blocks and smaller blocks through which cooling tubes containing fuel extend, said smaller blocks consisting alternately of tube bearing blocks and support block, the support blocks being smaller than the tube bearing blocks, the aperture of each support block being tapered so as to provide the tube extending therethrough with a narrow region of support while being elsewhere spaced therefrom.

Parallel dispatch: a new paradigm of electrical power system dispatch

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

Zhang, Jun Jason; Wang, Fei-Yue; Wang, Qiang

Modern power systems are evolving into sociotechnical systems with massive complexity, whose real-time operation and dispatch go beyond human capability. Thus, the need for developing and applying new intelligent power system dispatch tools are of great practical significance. In this paper, we introduce the overall business model of power system dispatch, the top level design approach of an intelligent dispatch system, and the parallel intelligent technology with its dispatch applications. We expect that a new dispatch paradigm, namely the parallel dispatch, can be established by incorporating various intelligent technologies, especially the parallel intelligent technology, to enable secure operation of complexmore » power grids, extend system operators U+02BC capabilities, suggest optimal dispatch strategies, and to provide decision-making recommendations according to power system operational goals.« less

Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction System

NASA Technical Reports Server (NTRS)

Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor)

2014-01-01

A novel full piezoelectric multilayer stacked hybrid actuation/transduction system. The system demonstrates significantly-enhanced electromechanical performance by utilizing the cooperative contributions of the electromechanical responses of multilayer stacked negative and positive strain components. Both experimental and theoretical studies indicate that for this system, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The system consists of at least 2 layers which include electromechanically active components. The layers are arranged such that when electric power is applied, one layer contracts in a transverse direction while the second layer expands in a transverse direction which is perpendicular to the transverse direction of the first layer. An alternate embodiment includes a third layer. In this embodiment, the outer two layers contract in parallel transverse directions while the middle layer expands in a transverse direction which is perpendicular to the transverse direction of the outer layers.

Reliability Analysis and Modeling of ZigBee Networks

NASA Astrophysics Data System (ADS)

Lin, Cheng-Min

The architecture of ZigBee networks focuses on developing low-cost, low-speed ubiquitous communication between devices. The ZigBee technique is based on IEEE 802.15.4, which specifies the physical layer and medium access control (MAC) for a low rate wireless personal area network (LR-WPAN). Currently, numerous wireless sensor networks have adapted the ZigBee open standard to develop various services to promote improved communication quality in our daily lives. The problem of system and network reliability in providing stable services has become more important because these services will be stopped if the system and network reliability is unstable. The ZigBee standard has three kinds of networks; star, tree and mesh. The paper models the ZigBee protocol stack from the physical layer to the application layer and analyzes these layer reliability and mean time to failure (MTTF). Channel resource usage, device role, network topology and application objects are used to evaluate reliability in the physical, medium access control, network, and application layers, respectively. In the star or tree networks, a series system and the reliability block diagram (RBD) technique can be used to solve their reliability problem. However, a division technology is applied here to overcome the problem because the network complexity is higher than that of the others. A mesh network using division technology is classified into several non-reducible series systems and edge parallel systems. Hence, the reliability of mesh networks is easily solved using series-parallel systems through our proposed scheme. The numerical results demonstrate that the reliability will increase for mesh networks when the number of edges in parallel systems increases while the reliability quickly drops when the number of edges and the number of nodes increase for all three networks. More use of resources is another factor impact on reliability decreasing. However, lower network reliability will occur due to network complexity, more resource usage and complex object relationship.

A plane wave model for direct simulation of reflection and transmission by discretely inhomogeneous plane parallel media

NASA Astrophysics Data System (ADS)

Mackowski, Daniel; Ramezanpour, Bahareh

2018-07-01

A formulation is developed for numerically solving the frequency domain Maxwell's equations in plane parallel layers of inhomogeneous media. As was done in a recent work [1], the plane parallel layer is modeled as an infinite square lattice of W × W × H unit cells, with W being a sample width of the layer and H the layer thickness. As opposed to the 3D volume integral/discrete dipole formulation, the derivation begins with a Fourier expansion of the electric field amplitude in the lateral plane, and leads to a coupled system of 1D ordinary differential equations in the depth direction of the layer. A 1D dyadic Green's function is derived for this system and used to construct a set of coupled 1D integral equations for the field expansion coefficients. The resulting mathematical formulation is considerably simpler and more compact than that derived, for the same system, using the discrete dipole approximation applied to the periodic plane lattice. Furthermore, the fundamental property variable appearing in the formulation is the Fourier transformed complex permittivity distribution in the unit cell, and the method obviates any need to define or calculate a dipole polarizability. Although designed primarily for random media calculations, the method is also capable of predicting the single scattering properties of individual particles; comparisons are presented to demonstrate that the method can accurately reproduce, at scattering angles not too close to 90°, the polarimetric scattering properties of single and multiple spheres. The derivation of the dyadic Green's function allows for an analytical preconditioning of the equations, and it is shown that this can result in significantly accelerated solution times when applied to densely-packed systems of particles. Calculation results demonstrate that the method, when applied to inhomogeneous media, can predict coherent backscattering and polarization opposition effects.

The characteristics of rotational slumps and subaqueous translational slab slides of the Lower Murray River, South Australia: do they have any implications for the weak-layer hypothesis?

NASA Astrophysics Data System (ADS)

Hubble, Thomas; De Carli, Elyssa; Airey, David; Breakfree 2012-2013, Scientific Parties MV

2014-05-01

The peak of the recent prolonged 'Millennium Drought' (1997-2011) triggered an episode of widespread mass failure in the alluvial river-banks of the Lower Murray River in South Australia. Multi-beam surveying of the channel and submerged river-banks between Mannum and Murray Bridge and coring of the bank sediments has been undertaken in sections of the river where large bank failures threatened private housing or public infrastructure. This data demonstrates that the bank materials are soft, horizontally-layered muds and that translational, planar slab-slides have frequently occurred in permanently submerged portions of the Murray's river banks. Despite these riverine features being several orders of magnitude smaller than the translational submarine landslides of the continental margins, the submerged river-bank slides are strikingly similar in their morphology to their submarine equivalents. Intriguingly, the Murray River translational slide failure-surfaces are usually developed as river-floor-parallel features in a manner similar to many submarine landslides which present failure-surfaces that are developed on seafloor-parallel, bedding planes. In contrast however, the Murray's river-bank slides occur on steep slopes (>20o) and their failure surfaces must cut across the horizontal laminations and layering of the muds at a relative high angle which removes the possibility of a weak sediment layer being responsible for the occurrence of these failures. Modelling of the river-bank failures with classical soil mechanics methods and the measured physical properties of the river-bank materials indicates that the failures are probably a consequence of flood-flow scour removing the bank-slope toe in combination with pore-pressure effects related to river-level fluctuation (ie. drawdown). Nevertheless, the Murray's translational slab-slides provide a reliable example of slope-parallel planar failure in muds that does not require a stratigraphic weak layer to explain the occurrence of those failures.

A psychoanalyst views inception.

PubMed

Clemens, Norman A

2013-05-01

The author, a psychoanalyst, discusses the 2010 film, Inception, discerning the parallels and differences between cinematic dreaming states as shown in the film and psychoanalytic processes. The movie presents the unknown and un-psychoanalytic phenomena of group shared dreaming, manipulation of other people's dreams with criminal intent, and multiple structured layers of dreaming. In parallel, however, the lead character appears to work through a complicated state of derealization, mourning, guilt, rage, and loss in the course of dreaming.

Early postnatal development of vasoactive intestinal polypeptide- and peptide histidine isoleucine-immunoreactive structures in the cat visual cortex.

PubMed

Wahle, P; Meyer, G

1989-04-08

The early postnatal development of neurons containing vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI) has been analyzed in visual areas 17 and 18 of cats aged from postnatal day (P) 0 to adulthood. Neuronal types are established mainly by axonal criteria. Both peptides occur in the same neuronal types and display the same postnatal chronology of appearance. Several cell types are transient, which means that they are present in the cortex only for a limited period of development. According to their chronology of appearance the VIP/PHI-immunoreactive (ir) cell types are grouped into three neuronal populations. The first population comprises six cell types which appear early in postnatal life. The pseudohorsetail cells of layer I possess a vertically descending axon which initially gives rise to recurrent collaterals, then forms a bundle passing layers III to V, and finally, horizontal terminal fibers in layer VI. The neurons differentiate at P 4 and disappear by degeneration around P 30. The neurons with columnar dendritic fields of layers IV/V are characterized by a vertical arrangement of long dendrites ascending or descending parallel to each other, thus forming an up to 600 microns long dendritic column. Their axons always descend and terminate in broad fields in layer VI. The neurons appear at P 7 and are present until P 20. The multipolar neurons of layer VI occur in isolated positions and have broad axonal territories. The neurons differentiate at P 7 and persist into adulthood. Bitufted to multipolar neurons of layers II/III have axons descending as a single fiber to layer VI, where they terminate. The neurons appear at P 12 and persist into adulthood. The four cell types described above issue a vertically oriented fiber architecture in layers II-V and a horizontal terminal plexus in layer VI which is dense during the second, third and fourth week. Concurrent with the disappearance of the two transient types the number of descending axonal bundles and the density of the layer VI plexus is reduced, but the latter is maintained during adulthood by the two persisting cell types. Two further cell types belong to the first population: The transient bipolar cells of layers IV, V, and VI have long dendrites which extend through the entire cortical width. Their axons always descend, leave the gray matter, and apparently terminate in the upper white matter. The neurons differentiate concurrently with the pseudohorsetail cells at P 4, are very frequent during the following weeks, and eventually disappear at P 30.(ABSTRACT TRUNCATED AT 400 WORDS)

Ion and electron dynamics generating the Hall current in the exhaust far downstream of the reconnection x-line

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

Fujimoto, Keizo, E-mail: keizo.fujimoto@nao.ac.jp; Takamoto, Makoto

2016-01-15

We have investigated the ion and electron dynamics generating the Hall current in the reconnection exhaust far downstream of the x-line where the exhaust width is much larger than the ion gyro-radius. A large-scale particle-in-cell simulation shows that most ions are accelerated through the Speiser-type motion in the current sheet formed at the center of the exhaust. The transition layers formed at the exhaust boundary are not identified as slow mode shocks. (The layers satisfy mostly the Rankine-Hugoniot conditions for a slow mode shock, but the energy conversion hardly occurs there.) We find that the ion drift velocity is modifiedmore » around the layer due to a finite Larmor radius effect. As a result, the ions are accumulated in the downstream side of the layer, so that collimated ion jets are generated. The electrons experience two steps of acceleration in the exhaust. The first is a parallel acceleration due to the out-of-plane electric field E{sub y} which has a parallel component in most area of the exhaust. The second is a perpendicular acceleration due to E{sub y} at the center of the current sheet and the motion is converted to the parallel direction. Because of the second acceleration, the electron outflow velocity becomes almost uniform over the exhaust. The difference in the outflow profile between the ions and electrons results in the Hall current in large area of the exhaust. The present study demonstrates the importance of the kinetic treatments for collisionless magnetic reconnection even far downstream from the x-line.« less

Interfacial Structures of Trihexyltetradecylphosphonium-bis(mandelato)borate Ionic Liquid Confined between Gold Electrodes.

PubMed

Wang, Yong-Lei; Golets, Mikhail; Li, Bin; Sarman, Sten; Laaksonen, Aatto

2017-02-08

Atomistic molecular dynamics simulations have been performed to study microscopic the interfacial ionic structures, molecular arrangements, and orientational preferences of trihexyltetradecylphosphonium-bis(mandelato)borate ([P 6,6,6,14 ][BMB]) ionic liquid confined between neutral and charged gold electrodes. It was found that both [P 6,6,6,14 ] cations and [BMB] anions are coabsorbed onto neutral electrodes at different temperatures. The hexyl and tetradecyl chains in [P 6,6,6,14 ] cations lie preferentially flat on neutral electrodes. The oxalato and phenyl rings in [BMB] anions are characterized by alternative parallel-perpendicular orientations in the mixed innermost ionic layer adjacent to neutral electrodes. An increase in temperature has a marginal effect on the interfacial ionic structures and molecular orientations of [P 6,6,6,14 ][BMB] ionic species in a confined environment. Electrifying gold electrodes leads to peculiar changes in the interfacial ionic structures and molecular orientational arrangements of [P 6,6,6,14 ] cations and [BMB] anions in negatively and positively charged gold electrodes, respectively. As surface charge density increases (but lower than 20 μC/cm 2 ), the layer thickness of the mixed innermost interfacial layer gradually increases due to a consecutive accumulation of [P 6,6,6,14 ] cations and [BMB] anions at negatively and positively charged electrodes, respectively, before the formation of distinct cationic and anionic innermost layers. Meanwhile, the molecular orientations of two oxalato rings in the same [BMB] anions change gradually from a parallel-perpendicular feature to being partially characterized by a tilted arrangement at an angle of 45° from the electrodes and finally to a dominant parallel coordination pattern along positively charged electrodes. Distinctive interfacial distribution patterns are also observed accordingly for phenyl rings that are directly connected to neighboring oxalato rings in [BMB] anions.

Code Parallelization with CAPO: A User Manual

NASA Technical Reports Server (NTRS)

Jin, Hao-Qiang; Frumkin, Michael; Yan, Jerry; Biegel, Bryan (Technical Monitor)

2001-01-01

A software tool has been developed to assist the parallelization of scientific codes. This tool, CAPO, extends an existing parallelization toolkit, CAPTools developed at the University of Greenwich, to generate OpenMP parallel codes for shared memory architectures. This is an interactive toolkit to transform a serial Fortran application code to an equivalent parallel version of the software - in a small fraction of the time normally required for a manual parallelization. We first discuss the way in which loop types are categorized and how efficient OpenMP directives can be defined and inserted into the existing code using the in-depth interprocedural analysis. The use of the toolkit on a number of application codes ranging from benchmark to real-world application codes is presented. This will demonstrate the great potential of using the toolkit to quickly parallelize serial programs as well as the good performance achievable on a large number of toolkit to quickly parallelize serial programs as well as the good performance achievable on a large number of processors. The second part of the document gives references to the parameters and the graphic user interface implemented in the toolkit. Finally a set of tutorials is included for hands-on experiences with this toolkit.

Broadband Venetian-Blind Polarizer With Dual Vanes

NASA Technical Reports Server (NTRS)

Conroy, Bruce L.; Hoppe, Daniel J.

1995-01-01

Improved venetian-blind polarizer features optimized tandem, two-layer vane configuration reducing undesired reflections and deformation of radiation pattern below those of prior single-layer vane configuration. Consists of number of thin, parallel metal strips placed in path of propagating radio-frequency beam. Offers simple way to convert polarization from linear to circular or from circular to linear. Particularly useful for beam-wave-guide applications.

When interflow also percolates: downslope travel distances and hillsclope process zones

Treesearch

C. Rhett Jackson; Menberu Bitew; Enhao Du

2014-01-01

In hillslopes with soils characterized by deep regoliths, such as Ultisols, Oxisols, and Alfisols, interflow occurs episodically over impeding layers near and parallel to the soil surface such as low-conductivity B horizons (e.g.Newman et al., 1998; Buttle and McDonald, 2002; Du et al., In Review), till layers (McGlynn et al., 1999; Bishop et al., 2004), hardpans (...

Micro hollow cathode discharge jets utilizing solid fuel

NASA Astrophysics Data System (ADS)

Nikic, Dejan

2017-10-01

Micro hollow cathode discharge devices with a solid fuel layer embedded between the electrodes have demonstrated an enhanced jetting process. Outlined are series of experiments in various pressure and gas conditions as well as vacuum. Examples of use of these devices in series and parallel configurations are presented. Evidence of utilization of solid fuel is obtained through optical spectroscopy and analysis of remaining fuel layer.

4H-SiC p i n diodes grown by sublimation epitaxy in vacuum (SEV) and their application as microwave diodes

NASA Astrophysics Data System (ADS)

Camara, N.; Zekentes, K.; Zelenin, V. V.; Abramov, P. L.; Kirillov, A. V.; Romanov, L. P.; Boltovets, N. S.; Krivutsa, V. A.; Thuaire, A.; Bano, E.; Tsoi, E.; Lebedev, A. A.

2008-02-01

Sublimation epitaxy under vacuum (SEV) was investigated as a method for growing 4H-SiC epitaxial structures for p-i-n diode fabrication. The SEV-grown 4H-SiC material was investigated with scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray diffraction, photo-luminescence spectroscopy (PL), cathodo-luminescence (CL) spectroscopy, photocurrent method for carrier diffusion length determination, electro-luminescence microscopy (EL), deep level transient spectroscopy (DLTS), C-V profiling and Hall-effect measurements. When possible, the same investigation techniques were used in parallel with similar layers grown by chemical vapour deposition (CVD) epitaxy and the physical properties of the two kind of epitaxied layers were compared. p-i-n diodes were fabricated in parallel on SEV and CVD-grown layers and showed close electrical performances in dc mode in term of capacitance, resistance and transient time switching, despite the lower mobility and the diffusion length of the SEV-grown layers. X-band microwave switches based on the SEV-grown p-i-n diodes have been demonstrated with insertion loss lower than 4 dB and an isolation higher than 17 dB. These single-pole single-throw (SPST) switches were able to handle a pulsed power up to 1800 W in isolation mode, similar to the value obtained with switches incorporating diodes with CVD-grown layers.

On the Lagrangian description of unsteady boundary-layer separation. I - General theory

NASA Technical Reports Server (NTRS)

Van Dommelen, Leon L.; Cowley, Stephen J.

1990-01-01

Although unsteady, high-Reynolds number, laminar boundary layers have conventionally been studied in terms of Eulerian coordinates, a Lagrangian approach may have significant analytical and computational advantages. In Lagrangian coordinates the classical boundary layer equations decouple into a momentum equation for the motion parallel to the boundary, and a hyperbolic continuity equation (essentially a conserved Jacobian) for the motion normal to the boundary. The momentum equations, plus the energy equation if the flow is compressible, can be solved independently of the continuity equation. Unsteady separation occurs when the continuity equation becomes singular as a result of touching characteristics, the condition for which can be expressed in terms of the solution of the momentum equations. The solutions to the momentum and energy equations remain regular. Asymptotic structures for a number of unsteady 3-D separating flows follow and depend on the symmetry properties of the flow. In the absence of any symmetry, the singularity structure just prior to separation is found to be quasi 2-D with a displacement thickness in the form of a crescent shaped ridge. Physically the singularities can be understood in terms of the behavior of a fluid element inside the boundary layer which contracts in a direction parallel to the boundary and expands normal to it, thus forcing the fluid above it to be ejected from the boundary layer.

On the Lagrangian description of unsteady boundary layer separation. Part 1: General theory

NASA Technical Reports Server (NTRS)

Vandommelen, Leon L.; Cowley, Stephen J.

1989-01-01

Although unsteady, high-Reynolds number, laminar boundary layers have conventionally been studied in terms of Eulerian coordinates, a Lagrangian approach may have significant analytical and computational advantages. In Lagrangian coordinates the classical boundary layer equations decouple into a momentum equation for the motion parallel to the boundary, and a hyperbolic continuity equation (essentially a conserved Jacobian) for the motion normal to the boundary. The momentum equations, plus the energy equation if the flow is compressible, can be solved independently of the continuity equation. Unsteady separation occurs when the continuity equation becomes singular as a result of touching characteristics, the condition for which can be expressed in terms of the solution of the momentum equations. The solutions to the momentum and energy equations remain regular. Asymptotic structures for a number of unsteady 3-D separating flows follow and depend on the symmetry properties of the flow. In the absence of any symmetry, the singularity structure just prior to separation is found to be quasi 2-D with a displacement thickness in the form of a crescent shaped ridge. Physically the singularities can be understood in terms of the behavior of a fluid element inside the boundary layer which contracts in a direction parallel to the boundary and expands normal to it, thus forcing the fluid above it to be ejected from the boundary layer.

Absolute/convective secondary instabilities and the role of confinement in free shear layers

NASA Astrophysics Data System (ADS)

Arratia, Cristóbal; Mowlavi, Saviz; Gallaire, François

2018-05-01

We study the linear spatiotemporal stability of an infinite row of equal point vortices under symmetric confinement between parallel walls. These rows of vortices serve to model the secondary instability leading to the merging of consecutive (Kelvin-Helmholtz) vortices in free shear layers, allowing us to study how confinement limits the growth of shear layers through vortex pairings. Using a geometric construction akin to a Legendre transform on the dispersion relation, we compute the growth rate of the instability in different reference frames as a function of the frame velocity with respect to the vortices. This approach is verified and complemented with numerical computations of the linear impulse response, fully characterizing the absolute/convective nature of the instability. Similar to results by Healey on the primary instability of parallel tanh profiles [J. Fluid Mech. 623, 241 (2009), 10.1017/S0022112008005284], we observe a range of confinement in which absolute instability is promoted. For a parallel shear layer with prescribed confinement and mixing length, the threshold for absolute/convective instability of the secondary pairing instability depends on the separation distance between consecutive vortices, which is physically determined by the wavelength selected by the previous (primary or pairing) instability. In the presence of counterflow and moderate to weak confinement, small (large) wavelength of the vortex row leads to absolute (convective) instability. While absolute secondary instabilities in spatially developing flows have been previously related to an abrupt transition to a complex behavior, this secondary pairing instability regenerates the flow with an increased wavelength, eventually leading to a convectively unstable row of vortices. We argue that since the primary instability remains active for large wavelengths, a spatially developing shear layer can directly saturate on the wavelength of such a convectively unstable row, by-passing the smaller wavelengths of absolute secondary instability. This provides a wavelength selection mechanism, according to which the distance between consecutive vortices should be sufficiently large in comparison with the channel width in order for the row of vortices to persist. We argue that the proposed wavelength selection criteria can serve as a guideline for experimentally obtaining plane shear layers with counterflow, which has remained an experimental challenge.

Performance Evaluation in Network-Based Parallel Computing

NASA Technical Reports Server (NTRS)

Dezhgosha, Kamyar

1996-01-01

Network-based parallel computing is emerging as a cost-effective alternative for solving many problems which require use of supercomputers or massively parallel computers. The primary objective of this project has been to conduct experimental research on performance evaluation for clustered parallel computing. First, a testbed was established by augmenting our existing SUNSPARCs' network with PVM (Parallel Virtual Machine) which is a software system for linking clusters of machines. Second, a set of three basic applications were selected. The applications consist of a parallel search, a parallel sort, a parallel matrix multiplication. These application programs were implemented in C programming language under PVM. Third, we conducted performance evaluation under various configurations and problem sizes. Alternative parallel computing models and workload allocations for application programs were explored. The performance metric was limited to elapsed time or response time which in the context of parallel computing can be expressed in terms of speedup. The results reveal that the overhead of communication latency between processes in many cases is the restricting factor to performance. That is, coarse-grain parallelism which requires less frequent communication between processes will result in higher performance in network-based computing. Finally, we are in the final stages of installing an Asynchronous Transfer Mode (ATM) switch and four ATM interfaces (each 155 Mbps) which will allow us to extend our study to newer applications, performance metrics, and configurations.

Visual Analysis of North Atlantic Hurricane Trends Using Parallel Coordinates and Statistical Techniques

DTIC Science & Technology

2008-07-07

analyzing multivariate data sets. The system was developed using the Java Development Kit (JDK) version 1.5; and it yields interactive performance on a... script and captures output from the MATLAB’s “regress” and “stepwisefit” utilities that perform simple and stepwise regression, respectively. The MATLAB...Statistical Association, vol. 85, no. 411, pp. 664–675, 1990. [9] H. Hauser, F. Ledermann, and H. Doleisch, “ Angular brushing of extended parallel coordinates

Vehicular impact absorption system

NASA Technical Reports Server (NTRS)

Knoell, A. C.; Wilson, A. H. (Inventor)

1978-01-01

An improved vehicular impact absorption system characterized by a plurality of aligned crash cushions of substantially cubic configuration is described. Each consists of a plurality of voided aluminum beverage cans arranged in substantial parallelism within a plurality of superimposed tiers and a covering envelope formed of metal hardware cloth. A plurality of cables is extended through the cushions in substantial parallelism with an axis of alignment for the cushions adapted to be anchored at each of the opposite end thereof.

A further extension of the Extended Parallel Process Model (E-EPPM): implications of cognitive appraisal theory of emotion and dispositional coping style.

PubMed

So, Jiyeon

2013-01-01

For two decades, the extended parallel process model (EPPM; Witte, 1992 ) has been one of the most widely used theoretical frameworks in health risk communication. The model has gained much popularity because it recognizes that, ironically, preceding fear appeal models do not incorporate the concept of fear as a legitimate and central part of them. As a remedy to this situation, the EPPM aims at "putting the fear back into fear appeals" ( Witte, 1992 , p. 330). Despite this attempt, however, this article argues that the EPPM still does not fully capture the essence of fear as an emotion. Specifically, drawing upon Lazarus's (1991 ) cognitive appraisal theory of emotion and the concept of dispositional coping style ( Miller, 1995 ), this article seeks to further extend the EPPM. The revised EPPM incorporates a more comprehensive perspective on risk perceptions as a construct involving both cognitive and affective aspects (i.e., fear and anxiety) and integrates the concept of monitoring and blunting coping style as a moderator of further information seeking regarding a given risk topic.

A fully coupled method for massively parallel simulation of hydraulically driven fractures in 3-dimensions: FULLY COUPLED PARALLEL SIMULATION OF HYDRAULIC FRACTURES IN 3-D

DOE PAGES

Settgast, Randolph R.; Fu, Pengcheng; Walsh, Stuart D. C.; ...

2016-09-18

This study describes a fully coupled finite element/finite volume approach for simulating field-scale hydraulically driven fractures in three dimensions, using massively parallel computing platforms. The proposed method is capable of capturing realistic representations of local heterogeneities, layering and natural fracture networks in a reservoir. A detailed description of the numerical implementation is provided, along with numerical studies comparing the model with both analytical solutions and experimental results. The results demonstrate the effectiveness of the proposed method for modeling large-scale problems involving hydraulically driven fractures in three dimensions.

Micropore extrusion-induced alignment transition from perpendicular to parallel of cylindrical domains in block copolymers.

PubMed

Qu, Ting; Zhao, Yongbin; Li, Zongbo; Wang, Pingping; Cao, Shubo; Xu, Yawei; Li, Yayuan; Chen, Aihua

2016-02-14

The orientation transition from perpendicular to parallel alignment of PEO cylindrical domains of PEO-b-PMA(Az) films has been demonstrated by extruding the block copolymer (BCP) solutions through a micropore of a plastic gastight syringe. The parallelized orientation of PEO domains induced by this micropore extrusion can be recovered to perpendicular alignment via ultrasonication of the extruded BCP solutions and subsequent annealing. A plausible mechanism is proposed in this study. The BCP films can be used as templates to prepare nanowire arrays with controlled layers, which has enormous potential application in the field of integrated circuits.

A fully coupled method for massively parallel simulation of hydraulically driven fractures in 3-dimensions: FULLY COUPLED PARALLEL SIMULATION OF HYDRAULIC FRACTURES IN 3-D

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

Settgast, Randolph R.; Fu, Pengcheng; Walsh, Stuart D. C.

This study describes a fully coupled finite element/finite volume approach for simulating field-scale hydraulically driven fractures in three dimensions, using massively parallel computing platforms. The proposed method is capable of capturing realistic representations of local heterogeneities, layering and natural fracture networks in a reservoir. A detailed description of the numerical implementation is provided, along with numerical studies comparing the model with both analytical solutions and experimental results. The results demonstrate the effectiveness of the proposed method for modeling large-scale problems involving hydraulically driven fractures in three dimensions.

An extension of the extended parallel process model (EPPM) in television health news: the influence of health consciousness on individual message processing and acceptance.

PubMed

Hong, Hyehyun

2011-06-01

The purpose of this study is to examine the role of health consciousness in processing TV news that contains potential health threats and preventive recommendations. Based on the extended parallel process model (Witte, 1992), relationships among health consciousness, perceived severity, perceived susceptibility, perceived response efficacy, perceived self-efficacy, and message acceptance/rejection were hypothesized. Responses collected from 175 participants after viewing four TV health news stories were analyzed using the bootstrapping analysis (Preacher & Hayes, 2008). Results confirmed three mediators (i.e., perceived severity, response efficacy, self-efficacy) in the influence of health consciousness on message acceptance. A negative association found between health consciousness and perceived susceptibility is discussed in relation to characteristics of health conscious individuals and optimistic bias of health risks.

Laser weld jig. [Patent application

DOEpatents

Van Blarigan, P.; Haupt, D.L.

1980-12-05

A system is provided for welding a workpiece along a predetermined weld line that may be of irregular shape, which includes the step of forming a lip on the workpiece to extend parallel to the weld line, and moving the workpiece by engaging the lip between a pair of rotatable members. Rotation of one of the members at a constant speed, causes the workpiece to move so that all points on the weld line sequentially pass a fixed point in space at a constant speed, so that a laser welding beam can be directed at that fixed point to form a weld along the weld line. The workpiece can include a reusable jig forming the lip, and with the jig constructed to detachably hold parts to be welded at a position wherein the weld line of the parts extends parallel to the lip on the jig.

An Overview of High-performance Parallel Big Data transfers over multiple network channels with Transport Layer Security (TLS) and TLS plus Perfect Forward Secrecy (PFS)

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

Fang, Chin; Corttrell, R. A.

This Technical Note provides an overview of high-performance parallel Big Data transfers with and without encryption for data in-transit over multiple network channels. It shows that with the parallel approach, it is feasible to carry out high-performance parallel "encrypted" Big Data transfers without serious impact to throughput. But other impacts, e.g. the energy-consumption part should be investigated. It also explains our rationales of using a statistics-based approach for gaining understanding from test results and for improving the system. The presentation is of high-level nature. Nevertheless, at the end we will pose some questions and identify potentially fruitful directions for futuremore » work.« less

Timing is everything: early degradation of abscission layer is associated with increased seed shattering in U.S. weedy rice

PubMed Central

2011-01-01

Background Seed shattering, or shedding, is an important fitness trait for wild and weedy grasses. U.S. weedy rice (Oryza sativa) is a highly shattering weed, thought to have evolved from non-shattering cultivated ancestors. All U.S. weedy rice individuals examined to date contain a mutation in the sh4 locus associated with loss of shattering during rice domestication. Weedy individuals also share the shattering trait with wild rice, but not the ancestral shattering mutation at sh4; thus, how weedy rice reacquired the shattering phenotype is unknown. To establish the morphological basis of the parallel evolution of seed shattering in weedy rice and wild, we examined the abscission layer at the flower-pedicel junction in weedy individuals in comparison with wild and cultivated relatives. Results Consistent with previous work, shattering wild rice individuals possess clear, defined abscission layers at flowering, whereas non-shattering cultivated rice individuals do not. Shattering weedy rice from two separately evolved populations in the U.S. (SH and BHA) show patterns of abscission layer formation and degradation distinct from wild rice. Prior to flowering, the abscission layer has formed in all weedy individuals and by flowering it is already degrading. In contrast, wild O. rufipogon abscission layers have been shown not to degrade until after flowering has occurred. Conclusions Seed shattering in weedy rice involves the formation and degradation of an abscission layer in the flower-pedicel junction, as in wild Oryza, but is a developmentally different process from shattering in wild rice. Weedy rice abscission layers appear to break down earlier than wild abscission layers. The timing of weedy abscission layer degradation suggests that unidentified regulatory genes may play a critical role in the reacquisition of shattering in weedy rice, and sheds light on the morphological basis of parallel evolution for shattering in weedy and wild rice. PMID:21235796

Timing is everything: early degradation of abscission layer is associated with increased seed shattering in U.S. weedy rice.

PubMed

Thurber, Carrie S; Hepler, Peter K; Caicedo, Ana L

2011-01-14

Seed shattering, or shedding, is an important fitness trait for wild and weedy grasses. U.S. weedy rice (Oryza sativa) is a highly shattering weed, thought to have evolved from non-shattering cultivated ancestors. All U.S. weedy rice individuals examined to date contain a mutation in the sh4 locus associated with loss of shattering during rice domestication. Weedy individuals also share the shattering trait with wild rice, but not the ancestral shattering mutation at sh4; thus, how weedy rice reacquired the shattering phenotype is unknown. To establish the morphological basis of the parallel evolution of seed shattering in weedy rice and wild, we examined the abscission layer at the flower-pedicel junction in weedy individuals in comparison with wild and cultivated relatives. Consistent with previous work, shattering wild rice individuals possess clear, defined abscission layers at flowering, whereas non-shattering cultivated rice individuals do not. Shattering weedy rice from two separately evolved populations in the U.S. (SH and BHA) show patterns of abscission layer formation and degradation distinct from wild rice. Prior to flowering, the abscission layer has formed in all weedy individuals and by flowering it is already degrading. In contrast, wild O. rufipogon abscission layers have been shown not to degrade until after flowering has occurred. Seed shattering in weedy rice involves the formation and degradation of an abscission layer in the flower-pedicel junction, as in wild Oryza, but is a developmentally different process from shattering in wild rice. Weedy rice abscission layers appear to break down earlier than wild abscission layers. The timing of weedy abscission layer degradation suggests that unidentified regulatory genes may play a critical role in the reacquisition of shattering in weedy rice, and sheds light on the morphological basis of parallel evolution for shattering in weedy and wild rice.

Magnetohydrodynamic generator electrode

DOEpatents

Marchant, David D.; Killpatrick, Don H.; Herman, Harold; Kuczen, Kenneth D.

1979-01-01

An improved electrode for use as a current collector in the channel of a magnetohydrodynamid (MHD) generator utilizes an elongated monolithic cap of dense refractory material compliantly mounted to the MHD channel frame for collecting the current. The cap has a central longitudinal channel which contains a first layer of porous refractory ceramic as a high-temperature current leadout from the cap and a second layer of resilient wire mesh in contact with the first layer as a low-temperature current leadout between the first layer and the frame. Also described is a monolithic ceramic insulator compliantly mounted to the frame parallel to the electrode by a plurality of flexible metal strips.

Architecture Adaptive Computing Environment

NASA Technical Reports Server (NTRS)

Dorband, John E.

2006-01-01

Architecture Adaptive Computing Environment (aCe) is a software system that includes a language, compiler, and run-time library for parallel computing. aCe was developed to enable programmers to write programs, more easily than was previously possible, for a variety of parallel computing architectures. Heretofore, it has been perceived to be difficult to write parallel programs for parallel computers and more difficult to port the programs to different parallel computing architectures. In contrast, aCe is supportable on all high-performance computing architectures. Currently, it is supported on LINUX clusters. aCe uses parallel programming constructs that facilitate writing of parallel programs. Such constructs were used in single-instruction/multiple-data (SIMD) programming languages of the 1980s, including Parallel Pascal, Parallel Forth, C*, *LISP, and MasPar MPL. In aCe, these constructs are extended and implemented for both SIMD and multiple- instruction/multiple-data (MIMD) architectures. Two new constructs incorporated in aCe are those of (1) scalar and virtual variables and (2) pre-computed paths. The scalar-and-virtual-variables construct increases flexibility in optimizing memory utilization in various architectures. The pre-computed-paths construct enables the compiler to pre-compute part of a communication operation once, rather than computing it every time the communication operation is performed.

Thermal Casimir and Casimir–Polder interactions in N parallel 2D Dirac materials

NASA Astrophysics Data System (ADS)

Khusnutdinov, Nail; Kashapov, Rashid; Woods, Lilia M.

2018-07-01

The Casimir and Casimir–Polder interactions are investigated in a stack of equally spaced graphene layers. The optical response of the individual graphene is taken into account using gauge invariant components of the polarization tensor extended to the whole complex frequency plane. The planar symmetry for the electromagnetic boundary conditions is further used to obtain explicit forms for the Casimir energy stored in the stack and the Casimir–Polder energy between an atom above the stack. Our calculations show that these fluctuation induced interactions experience strong thermal effects due to the graphene Dirac-like energy spectrum. The spatial dispersion and temperature dependence in the optical response are also found to be important for enhancing the interactions especially at smaller separations. Analytical expressions for low and high temperature limits and their comparison with corresponding expressions for an infinitely conducting planar stack are further used to expand our understanding of Casimir and Casimir–Polder energies in Dirac materials. Our results may be useful to experimentalists as new ways to probe thermal effects at the nanoscale in such universal interactions.

Poly[bis­{3,3′-[(biphenyl-4,4′-di­yl)dimethyl­ene]diimidazol-1-ium} γ-octa­molybdate(VI)

PubMed Central

Liu, Hongsheng; Su, Lianjiang; Wang, Limin; Li, Weihong

2010-01-01

In the title compound, {(C20H20N4)2[Mo8O26]}n, the asymmetric unit contains half of an [Mo8O26]4− anion and one 3,3′-[(biphenyl-4,4′-di­yl)dimethyl­ene]diimidazol-1-ium dication. In the anion, four distorted [MoO6] octa­hedra are connected via edge-sharing, forming an [Mo4O13]2− building block, composed of Mo—O(t), Mo—O(μ2), Mo—O(μ3) and Mo—O(μ4) units, with Mo—O distances ranging from 1.6858 (15) to 2.4785 (13) Å. The γ-type [Mo8O26]4− anion is completed by crystallographic inversion symmetry and is linked into an infinite chain along [100] by corner-sharing. The anionic chains and the cations are joined by N—H⋯O hydrogen bonds, generating layers extending parallel to (001). PMID:21580534

Algorithm for computing descriptive statistics for very large data sets and the exa-scale era

NASA Astrophysics Data System (ADS)

Beekman, Izaak

2017-11-01

An algorithm for Single-point, Parallel, Online, Converging Statistics (SPOCS) is presented. It is suited for in situ analysis that traditionally would be relegated to post-processing, and can be used to monitor the statistical convergence and estimate the error/residual in the quantity-useful for uncertainty quantification too. Today, data may be generated at an overwhelming rate by numerical simulations and proliferating sensing apparatuses in experiments and engineering applications. Monitoring descriptive statistics in real time lets costly computations and experiments be gracefully aborted if an error has occurred, and monitoring the level of statistical convergence allows them to be run for the shortest amount of time required to obtain good results. This algorithm extends work by Pébay (Sandia Report SAND2008-6212). Pébay's algorithms are recast into a converging delta formulation, with provably favorable properties. The mean, variance, covariances and arbitrary higher order statistical moments are computed in one pass. The algorithm is tested using Sillero, Jiménez, & Moser's (2013, 2014) publicly available UPM high Reynolds number turbulent boundary layer data set, demonstrating numerical robustness, efficiency and other favorable properties.

Clustering on Magnesium Surfaces – Formation and Diffusion Energies

DOE PAGES

Chu, Haijian; Huang, Hanchen; Wang, Jian

2017-07-12

The formation and diffusion energies of atomic clusters on Mg surfaces determine the surface roughness and formation of faulted structure, which in turn affect the mechanical deformation of Mg. This paper reports first principles density function theory (DFT) based quantum mechanics calculation results of atomic clustering on the low energy surfaces {0001} and {more » $$\\bar{1}$$011} . In parallel, molecular statics calculations serve to test the validity of two interatomic potentials and to extend the scope of the DFT studies. On a {0001} surface, a compact cluster consisting of few than three atoms energetically prefers a face-centered-cubic stacking, to serve as a nucleus of stacking fault. On a {$$\\bar{1}$$011} , clusters of any size always prefer hexagonal-close-packed stacking. Adatom diffusion on surface {$$\\bar{1}$$011} is high anisotropic while isotropic on surface (0001). Three-dimensional Ehrlich–Schwoebel barriers converge as the step height is three atomic layers or thicker. FInally, adatom diffusion along steps is via hopping mechanism, and that down steps is via exchange mechanism.« less

Clustering on Magnesium Surfaces – Formation and Diffusion Energies

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

Chu, Haijian; Huang, Hanchen; Wang, Jian

The formation and diffusion energies of atomic clusters on Mg surfaces determine the surface roughness and formation of faulted structure, which in turn affect the mechanical deformation of Mg. This paper reports first principles density function theory (DFT) based quantum mechanics calculation results of atomic clustering on the low energy surfaces {0001} and {more » $$\\bar{1}$$011} . In parallel, molecular statics calculations serve to test the validity of two interatomic potentials and to extend the scope of the DFT studies. On a {0001} surface, a compact cluster consisting of few than three atoms energetically prefers a face-centered-cubic stacking, to serve as a nucleus of stacking fault. On a {$$\\bar{1}$$011} , clusters of any size always prefer hexagonal-close-packed stacking. Adatom diffusion on surface {$$\\bar{1}$$011} is high anisotropic while isotropic on surface (0001). Three-dimensional Ehrlich–Schwoebel barriers converge as the step height is three atomic layers or thicker. FInally, adatom diffusion along steps is via hopping mechanism, and that down steps is via exchange mechanism.« less

Crater Moreux

NASA Technical Reports Server (NTRS)

1997-01-01

Color image of part of the Ismenius Lacus region of Mars (MC-5 quadrangle) containing the impact crater Moreux (right center); north toward top. The scene shows heavily cratered highlands in the south on relatively smooth lowland plains in the north separated by a belt of dissected terrain, containing flat-floored valleys, mesas, and buttes. This image is a composite of Viking medium-resolution images in black and white and low-resolution images in color. The image extends from latitude 36 degrees N. to 50 degrees N. and from longitude 310 degrees to 340 degrees; Lambert conformal conic projection. The dissected terrain along the highlands/lowlands boundary consists of the flat-floored valleys of Deuteronilus Mensae (on left) and Prontonilus Mensae (on right) and farther north the small, rounded hills of knobby terrain. Flows on the mensae floors contain striae that run parallel to valley walls; where valleys meet, the striae merge, similar to medial moraines on glaciers. Terraces within the valley hills have been interpreted as either layered rocks or wave terraces. The knobby terrain has been interpreted as remnants of the old, densely cratered highland terrain perhaps eroded by mass wasting.

Influence of electrolytes in the QCM response: discrimination and quantification of the interference to correct microgravimetric data.

PubMed

Encarnação, João M; Stallinga, Peter; Ferreira, Guilherme N M

2007-02-15

In this work we demonstrate that the presence of electrolytes in solution generates desorption-like transients when the resonance frequency is measured. Using impedance spectroscopy analysis and Butterworth-Van Dyke (BVD) equivalent electrical circuit modeling we demonstrate that non-Kanazawa responses are obtained in the presence of electrolytes mainly due to the formation of a diffuse electric double layer (DDL) at the sensor surface, which also causes a capacitor like signal. We extend the BVD equivalent circuit by including additional parallel capacitances in order to account for such capacitor like signal. Interfering signals from electrolytes and DDL perturbations were this way discriminated. We further quantified as 8.0+/-0.5 Hz pF-1 the influence of electrolytes to the sensor resonance frequency and we used this factor to correct the data obtained by frequency counting measurements. The applicability of this approach is demonstrated by the detection of oligonucleotide sequences. After applying the corrective factor to the frequency counting data, the mass contribution to the sensor signal yields identical values when estimated by impedance analysis and frequency counting.

A real time neural net estimator of fatigue life

NASA Technical Reports Server (NTRS)

Troudet, T.; Merrill, W.

1990-01-01

A neural network architecture is proposed to estimate, in real-time, the fatigue life of mechanical components, as part of the intelligent Control System for Reusable Rocket Engines. Arbitrary component loading values were used as input to train a two hidden-layer feedforward neural net to estimate component fatigue damage. The ability of the net to learn, based on a local strain approach, the mapping between load sequence and fatigue damage has been demonstrated for a uniaxial specimen. Because of its demonstrated performance, the neural computation may be extended to complex cases where the loads are biaxial or triaxial, and the geometry of the component is complex (e.g., turbopumps blades). The generality of the approach is such that load/damage mappings can be directly extracted from experimental data without requiring any knowledge of the stress/strain profile of the component. In addition, the parallel network architecture allows real-time life calculations even for high-frequency vibrations. Owing to its distributed nature, the neural implementation will be robust and reliable, enabling its use in hostile environments such as rocket engines.

Dependence of astigmatism, far-field pattern, and spectral envelope width on active layer thickness of gain guided lasers with narrow stripe geometry

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

Mamine, T.

1984-06-15

The effects of active layer thickness on the astigmatism, the angle of far-field pattern width parallel to the junction, and the spectral envelope width of a gain guided laser with a narrow stripe geometry have been investigated analytically and experimentally. It is concluded that a large level of astigmatism, a narrow far-field pattern width, and a rapid convergence of the spectral envelope width are inherent to the gain guided lasers with thin active layers.

Investigation of 2-Dimensional Isotropy of Under-Ice Roughness in the Beaufort Gyre and Implications for Mixed Layer Ocean Turbulence

DTIC Science & Technology

2008-03-01

this roughness is important for numerical modeling and prediction of the Arctic air-ice-ocean system, which will play a significant role as the US Navy...is important for numerical modeling and prediction of the Arctic air-ice-ocean system, which will play a significant role as the US Navy increases... Model 1 is based on a sequence of plane parallel layers each with a constant gradient whereas Model 2 is based on a series of flat layers of

Separate the inseparable one-layer mapping

NASA Astrophysics Data System (ADS)

Hu, Chia-Lun J.

2000-04-01

When the input-output mapping of a one-layered perceptron (OLP) does NOT meet the PLI condition which is the if-and- only-if, or 'IFF, condition that the mapping can be realized by a OLP, then no matter what learning rule we use, a OLP just cannot realize this mapping at all. However, because of the nature of the PLI, one can still construct a parallel- cascaded, two-layered perceptron system to realize this `illegal' mapping. Theory and design example of this novel design will be reported in detail in this paper.

Organic light emitting diodes with structured electrodes

DOEpatents

Mao, Samuel S.; Liu, Gao; Johnson, Stephen G.

2012-12-04

A cathode that contain nanostructures that extend into the organic layer of an OLED has been described. The cathode can have an array of nanotubes or a layer of nanoclusters extending out from its surface. In another arrangement, the cathode is patterned and etched to form protruding nanostructures using a standard lithographic process. Various methods for fabricating these structures are provided, all of which are compatible with large-scale manufacturing. OLEDs made with these novel electrodes have greatly enhanced electron injection, have good environmental stability.

Electrostatic repulsive out-of-plane actuator using conductive substrate.

PubMed

Wang, Weimin; Wang, Qiang; Ren, Hao; Ma, Wenying; Qiu, Chuankai; Chen, Zexiang; Fan, Bin

2016-10-07

A pseudo-three-layer electrostatic repulsive out-of-plane actuator is proposed. It combines the advantages of two-layer and three-layer repulsive actuators, i.e., fabrication requirements and fill factor. A theoretical model for the proposed actuator is developed and solved through the numerical calculation of Schwarz-Christoffel mapping. Theoretical and simulated results show that the pseudo-three-layer actuator offers higher performance than the two-layer and three-layer actuators with regard to the two most important characteristics of actuators, namely, driving force and theoretical stroke. Given that the pseudo-three-layer actuator structure is compatible with both the parallel-plate actuators and these two types of repulsive actuators, a 19-element two-layer repulsive actuated deformable mirror is operated in pseudo-three-layer electrical connection mode. Theoretical and experimental results demonstrate that the pseudo-three-layer mode produces a larger displacement of 0-4.5 μm for a dc driving voltage of 0-100 V, when compared with that in two-layer mode.

Electrostatic repulsive out-of-plane actuator using conductive substrate

PubMed Central

Wang, Weimin; Wang, Qiang; Ren, Hao; Ma, Wenying; Qiu, Chuankai; Chen, Zexiang; Fan, Bin

2016-01-01

A pseudo-three-layer electrostatic repulsive out-of-plane actuator is proposed. It combines the advantages of two-layer and three-layer repulsive actuators, i.e., fabrication requirements and fill factor. A theoretical model for the proposed actuator is developed and solved through the numerical calculation of Schwarz-Christoffel mapping. Theoretical and simulated results show that the pseudo-three-layer actuator offers higher performance than the two-layer and three-layer actuators with regard to the two most important characteristics of actuators, namely, driving force and theoretical stroke. Given that the pseudo-three-layer actuator structure is compatible with both the parallel-plate actuators and these two types of repulsive actuators, a 19-element two-layer repulsive actuated deformable mirror is operated in pseudo-three-layer electrical connection mode. Theoretical and experimental results demonstrate that the pseudo-three-layer mode produces a larger displacement of 0–4.5 μm for a dc driving voltage of 0–100 V, when compared with that in two-layer mode. PMID:27713542

Dynamical features and electric field strengths of double layers driven by currents. [in auroras

NASA Technical Reports Server (NTRS)

Singh, N.; Thiemann, H.; Schunk, R. W.

1985-01-01

In recent years, a number of papers have been concerned with 'ion-acoustic' double layers. In the present investigation, results from numerical simulations are presented to show that the shapes and forms of current-driven double layers evolve dynamically with the fluctuations in the current through the plasma. It is shown that double layers with a potential dip can form even without the excitation of ion-acoustic modes. Double layers in two-and one-half-dimensional simulations are discussed, taking into account the simulation technique, the spatial and temporal features of plasma, and the dynamical behavior of the parallel potential distribution. Attention is also given to double layers in one-dimensional simulations, and electrical field strengths predicted by two-and one-half-dimensional simulations.

Fast Whole-Engine Stirling Analysis

NASA Technical Reports Server (NTRS)

Dyson, Rodger W.; Wilson, Scott D.; Tew, Roy C.; Demko, Rikako

2006-01-01

This presentation discusses the simulation approach to whole-engine for physical consistency, REV regenerator modeling, grid layering for smoothness, and quality, conjugate heat transfer method adjustment, high-speed low cost parallel cluster, and debugging.

Fracture propagation through a layered shale and limestone sequence at Nash Point, South Wales: Implications on the development of fracture networks in layered sequences

NASA Astrophysics Data System (ADS)

Forbes Inskip, N.; Meredith, P. G.; Gudmundsson, A.

2017-12-01

While considerable effort has been expended on the study of fracture propagation in rocks in recent years, our understanding of how fractures propagate through sedimentary rocks composed of layers with different mechanical and elastic properties remains poor. Yet the mechanical layering is a key parameter controlling the propagation of fractures in sedimentary sequences. Here we report measurements of the contrasting properties of the Lower Lias at Nash Point, South Wales, which comprises a sequence of interbedded shale and limestone layers, and how those properties influence fracture propagation. The static Young's modulus (Estat) of both rock types has been measured parallel and normal to bedding. The shale is highly anisotropic, with Estat varying from 2.4 GPa, in the bedding-normal orientation, to 7.9 GPa, in the bedding-parallel orientation, yielding an anisotropy of 107%. By contrast the limestone has a very low anisotropy of 8%, with Estat values varying from 28.5 GPa, in the bedding-normal orientation, to 26.3 GPa in the bedding-parallel orientation. It follows that for a vertical fracture propagating in this sequence the modulus contrast is by a factor of about 12. This is important because the contrast in elastic properties is a key factor in controlling whether fractures arrest, deflect, or propagate across interfaces between layers in a sequence. Preliminary numerical modelling results (using a finite element modelling software) of induced fractures at Nash Point demonstrate a rotation of the maximum principal compressive stress across interfaces but also the concentration of tensile stress within the more competent (high Estat) limestone layers. The tensile strength (σT), using the Brazil-disk technique, and fracture toughness (KIc), using the semi-circular bend methodology, of both rock types have been measured. Measurements were made in the three principal orientations relative to bedding, Arrester, Divider, and Short-Transverse, and also at 15° intervals between these planes. Again, values for the shale show a high degree of anisotropy; with similar values in the Arrester and Divider orientations, but much lower values in the Short-Transverse orientation. σT and KIc values for the limestone are considerably higher than those for the shale and exhibit no significant anisotropy.

Cathode for a hall-heroult type electrolytic cell for producing aluminum

DOEpatents

Brown, Craig W.

2004-04-13

A method of producing aluminum from alumina in an electrolytic cell including using a cathode comprised of a base material having low electrical conductivity and wettable with molten aluminum to form a reaction layer having a high electrical conductivity on said base layer and a cathode bar extending from said reaction layer through said base material to conduct electrical current from said reaction layer.

Neutronic reactor

DOEpatents

Lewis, Warren R.

1978-05-30

A graphite-moderated, water-cooled nuclear reactor including a plurality of rectangular graphite blocks stacked in abutting relationship in layers, alternate layers having axes which are normal to one another, alternate rows of blocks in alternate layers being provided with a channel extending through the blocks, said channeled blocks being provided with concave sides and having smaller vertical dimensions than adjacent blocks in the same layer, there being nuclear fuel in the channels.

Accelerating semantic graph databases on commodity clusters

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

Morari, Alessandro; Castellana, Vito G.; Haglin, David J.

We are developing a full software system for accelerating semantic graph databases on commodity cluster that scales to hundreds of nodes while maintaining constant query throughput. Our framework comprises a SPARQL to C++ compiler, a library of parallel graph methods and a custom multithreaded runtime layer, which provides a Partitioned Global Address Space (PGAS) programming model with fork/join parallelism and automatic load balancing over a commodity clusters. We present preliminary results for the compiler and for the runtime.

The Interior Layered Deposits of Valles Marineris: Layering, Erosional Processes, and Age Relationships

NASA Technical Reports Server (NTRS)

Weitz, C. M.; Parker, T.; Anderson, F. S.; Grant, J. A.

2001-01-01

We have used Viking and Mars Global Surveyor data to study the interior layered deposits in detail. We have identified features which may support fluvial activity within Valles Marineris. Stratigraphic relationships indicate the deposits are younger than the wallrock. Additional information is contained in the original extended abstract.

Turbulence modeling of free shear layers for high performance aircraft

NASA Technical Reports Server (NTRS)

Sondak, Douglas

1993-01-01

In many flowfield computations, accuracy of the turbulence model employed is frequently a limiting factor in the overall accuracy of the computation. This is particularly true for complex flowfields such as those around full aircraft configurations. Free shear layers such as wakes, impinging jets (in V/STOL applications), and mixing layers over cavities are often part of these flowfields. Although flowfields have been computed for full aircraft, the memory and CPU requirements for these computations are often excessive. Additional computer power is required for multidisciplinary computations such as coupled fluid dynamics and conduction heat transfer analysis. Massively parallel computers show promise in alleviating this situation, and the purpose of this effort was to adapt and optimize CFD codes to these new machines. The objective of this research effort was to compute the flowfield and heat transfer for a two-dimensional jet impinging normally on a cool plate. The results of this research effort were summarized in an AIAA paper titled 'Parallel Implementation of the k-epsilon Turbulence Model'. Appendix A contains the full paper.

Pulsating Magnetic Reconnection Driven by Three-Dimensional Flux-Rope Interactions.

PubMed

Gekelman, W; De Haas, T; Daughton, W; Van Compernolle, B; Intrator, T; Vincena, S

2016-06-10

The dynamics of magnetic reconnection is investigated in a laboratory experiment consisting of two magnetic flux ropes, with currents slightly above the threshold for the kink instability. The evolution features periodic bursts of magnetic reconnection. To diagnose this complex evolution, volumetric three-dimensional data were acquired for both the magnetic and electric fields, allowing key field-line mapping quantities to be directly evaluated for the first time with experimental data. The ropes interact by rotating about each other and periodically bouncing at the kink frequency. During each reconnection event, the formation of a quasiseparatrix layer (QSL) is observed in the magnetic field between the flux ropes. Furthermore, a clear correlation is demonstrated between the quasiseparatrix layer and enhanced values of the quasipotential computed by integrating the parallel electric field along magnetic field lines. These results provide clear evidence that field lines passing through the quasiseparatrix layer are undergoing reconnection and give a direct measure of the nonlinear reconnection rate. The measurements suggest that the parallel electric field within the QSL is supported predominantly by electron pressure; however, resistivity may play a role.

Infrared Transition Moment Directions in Smectic Liquid Crystals

NASA Astrophysics Data System (ADS)

Park, C. S.; Jang, W. G.; Coleman, D.; Glaser, M. A.; Clark, N. A.

1997-03-01

We have investigated the variation of absorbance with polarization for C=O, O-H, and phenyl stretch modes in aligned smectic liquid crystals, for IR radiation propagating parallel to the smectic layers. For the C=O stretch, maximum absorbance is generally observed for radiation polarized perpendicular to the layer normal in the smectic A phase, consistent with the assumption that the IR transition moment direction is coincident with the C=O bond (oriented at an angle of ~ 60^circ with respect to the molecular long axis). In certain cases, however, maximum absorbance is observed for incident polarization parallel to the layer normal, and in general observed dichroic ratios depend sensitively on the nature of the functional groups surrounding the carbonyl moiety. Similar chemical sensitivity is observed for the phenyl and O-H stretch modes. We have succeeding in interpreting these measurements by calculating IR transition moment directions for the most important vibrational modes of several model compounds using quantum chemical methods, including HF/6-311G SCF and B3LYP/6-311G and B3LYP/6-31G DFT calculations.

Thermally conductive lithium ion electrodes and batteries

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

Shevchenko, Elena; Sumant, Anirudha V.; Balandin, Alexander

A thermally conductive electrochemical cell comprises a lithium ion-containing liquid electrolyte contacting a cathode and anode. The cathode and anode are in the form of electroactive sheets separated from each other by a membrane that is permeable to the electrolyte. One or more of the cathode and anode comprises two or more layers of carbon nanotubes, one of which layers includes electrochemically active nanoparticles and/or microparticles disposed therein or deposited on the nanotubes thereof. The majority of the carbon nanotubes in each of the layers are oriented generally parallel to the layers. Optionally, one or more of the layers includesmore » an additional carbon material such as graphene, nanoparticulate diamond, microparticulate diamond, and a combination thereof.« less

Properties of dielectric dead layers for SrTiO3 thin films on Pt electrodes

NASA Astrophysics Data System (ADS)

Finstrom, Nicholas H.; Cagnon, Joel; Stemmer, Susanne

2007-02-01

Dielectric measurements as a function of temperature were used to characterize the properties of the dielectric dead layers in parallel-plate capacitors with differently textured SrTiO3 thin films and Pt electrodes. The apparent thickness dependence of the permittivity was described with low-permittivity passive (dead) layers at the interfaces connected in series with the bulk of the SrTiO3 film. Interfacial capacitance densities changed with the film microstructure and were weakly temperature dependent. Estimates of the dielectric dead layer thickness and permittivity were limited by the film surface roughness (˜5nm ). The consequences for the possible origins of dielectric dead layers that have been proposed in the literature are discussed.

Retrieval of phase information in neutron reflectometry

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

de Haan, V.; van Well, A.A.; Adenwalla, S.

Neutron reflectometry can determine unambiguously the chemical depth profile of a thin film if both phase and amplitude of the reflectance are known. The recovery of the phase information is achieved by adding to the unknown layered structure a known ferromagnetic layer. The ferromagnetic layer is magnetized by an external magnetic field in a direction lying in the plane of the layer and subsequently perpendicular to it. The neutrons are polarized either parallel or opposite to the magnetic field. In this way three measurements can be made, with different (and known) scattering-length densities of the ferromagnetic layer. The reflectivity obtainedmore » from each measurement can be represented by a circle in the (complex) reflectance plane. The intersections of these circles provide the reflectance.« less

[PVFS 2000: An operational parallel file system for Beowulf

NASA Technical Reports Server (NTRS)

Ligon, Walt

2004-01-01

The approach has been to develop Parallel Virtual File System version 2 (PVFS2) , retaining the basic philosophy of the original file system but completely rewriting the code. It shows the architecture of the server and client components. BMI - BMI is the network abstraction layer. It is designed with a common driver and modules for each protocol supported. The interface is non-blocking, and provides mechanisms for optimizations including pinning user buffers. Currently TCP/IP and GM(Myrinet) modules have been implemented. Trove -Trove is the storage abstraction layer. It provides for storing both data spaces and name/value pairs. Trove can also be implemented using different underlying storage mechanisms including native files, raw disk partitions, SQL and other databases. The current implementation uses native files for data spaces and Berkeley db for name/value pairs.

A gyrokinetic one-dimensional scrape-off layer model of an edge-localized mode heat pulse

DOE PAGES

Shi, E. L.; Hakim, A. H.; Hammett, G. W.

2015-02-03

An electrostatic gyrokinetic-based model is applied to simulate parallel plasma transport in the scrape-off layer to a divertor plate. We focus on a test problem that has been studied previously, using parameters chosen to model a heat pulse driven by an edge-localized mode in JET. Previous work has used direct particle-in-cellequations with full dynamics, or Vlasov or fluid equations with only parallel dynamics. With the use of the gyrokinetic quasineutrality equation and logical sheathboundary conditions, spatial and temporal resolution requirements are no longer set by the electron Debye length and plasma frequency, respectively. Finally, this test problem also helps illustratemore » some of the physics contained in the Hamiltonian form of the gyrokineticequations and some of the numerical challenges in developing an edge gyrokinetic code.« less

Extended volume and surface scatterometer for optical characterization of 3D-printed elements

NASA Astrophysics Data System (ADS)

Dannenberg, Florian; Uebeler, Denise; Weiß, Jürgen; Pescoller, Lukas; Weyer, Cornelia; Hahlweg, Cornelius

2015-09-01

The use of 3d printing technology seems to be a promising way for low cost prototyping, not only of mechanical, but also of optical components or systems. It is especially useful in applications where customized equipment repeatedly is subject to immediate destruction, as in experimental detonics and the like. Due to the nature of the 3D-printing process, there is a certain inner texture and therefore inhomogeneous optical behaviour to be taken into account, which also indicates mechanical anisotropy. Recent investigations are dedicated to quantification of optical properties of such printed bodies and derivation of corresponding optimization strategies for the printing process. Beside mounting, alignment and illumination means, also refractive and reflective elements are subject to investigation. The proposed measurement methods are based on an imaging nearfield scatterometer for combined volume and surface scatter measurements as proposed in previous papers. In continuation of last year's paper on the use of near field imaging, which basically is a reflective shadowgraph method, for characterization of glossy surfaces like printed matter or laminated material, further developments are discussed. The device has been extended for observation of photoelasticity effects and therefore homogeneity of polarization behaviour. A refined experimental set-up is introduced. Variation of plane of focus and incident angle are used for separation of various the images of the layers of the surface under test, cross and parallel polarization techniques are applied. Practical examples from current research studies are included.

Exact simulation of polarized light reflectance by particle deposits

NASA Astrophysics Data System (ADS)

Ramezan Pour, B.; Mackowski, D. W.

2015-12-01

The use of polarimetric light reflection measurements as a means of identifying the physical and chemical characteristics of particulate materials obviously relies on an accurate model of predicting the effects of particle size, shape, concentration, and refractive index on polarized reflection. The research examines two methods for prediction of reflection from plane parallel layers of wavelength—sized particles. The first method is based on an exact superposition solution to Maxwell's time harmonic wave equations for a deposit of spherical particles that are exposed to a plane incident wave. We use a FORTRAN-90 implementation of this solution (the Multiple Sphere T Matrix (MSTM) code), coupled with parallel computational platforms, to directly simulate the reflection from particle layers. The second method examined is based upon the vector radiative transport equation (RTE). Mie theory is used in our RTE model to predict the extinction coefficient, albedo, and scattering phase function of the particles, and the solution of the RTE is obtained from adding—doubling method applied to a plane—parallel configuration. Our results show that the MSTM and RTE predictions of the Mueller matrix elements converge when particle volume fraction in the particle layer decreases below around five percent. At higher volume fractions the RTE can yield results that, depending on the particle size and refractive index, significantly depart from the exact predictions. The particle regimes which lead to dependent scattering effects, and the application of methods to correct the vector RTE for particle interaction, will be discussed.

Banana regime pressure anisotropy in a bumpy cylinder magnetic field

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

Garcia-Perciante, A.L.; Callen, J.D.; Shaing, K.C.

The pressure anisotropy is calculated for a plasma in a bumpy cylindrical magnetic field in the low collisionality (banana) regime for small magnetic-field modulations ({epsilon}{identical_to}{delta}B/2B<<1). Solutions are obtained by integrating the drift-kinetic equation along field lines in steady state. A closure for the local value of the parallel viscous force B{center_dot}{nabla}{center_dot}{pi}{sub parallel} is then calculated and is shown to exceed the flux-surface-averaged parallel viscous force by a factor of O(1/{epsilon}). A high-frequency limit ({omega}>>{nu}) for the pressure anisotropy is also determined and the calculation is then extended to include the full frequency dependence by using an expansion inmore » Cordey eigenfunctions.« less

Large-scale fabrication of vertically aligned ZnO nanowire arrays

DOEpatents

Wang, Zhong Lin; Hu, Youfan; Zhang, Yan; Xu, Chen; Zhu, Guang

2014-09-09

A generator includes a substrate, a first electrode layer, a dense plurality of vertically-aligned piezoelectric elongated nanostructures, an insulating layer and a second electrode layer. The substrate has a top surface and the first electrode layer is disposed on the top surface of the substrate. The dense plurality of vertically-aligned piezoelectric elongated nanostructures extends from the first electrode layer. Each of the nanostructures has a top end. The insulating layer is disposed on the top ends of the nanostructures. The second electrode layer is disposed on the non-conductive layer and is spaced apart from the nanostructures.

Linearized potential solution for an airfoil in nonuniform parallel streams

NASA Technical Reports Server (NTRS)

Prabhu, R. K.; Tiwari, S. N.

1983-01-01

A small perturbation potential flow theory is applied to the problem of determining the chordwise pressure distribution, lift and pitching moment of a thin airfoil in the middle of five parallel streams. This theory is then extended to the case of an undisturbed stream having a given smooth velocity profile. Two typical examples are considered and the results obtained are compared with available solutions of Euler's equations. The agreement between these two results is not quite satisfactory. Possible reasons for the differences are indicated.

On the relationship between collisionless shock structure and energetic particle acceleration

NASA Technical Reports Server (NTRS)

Kennel, C. F.

1983-01-01

Recent experimental research on bow shock structure and theoretical studies of quasi-parallel shock structure and shock acceleration of energetic particles were reviewed, to point out the relationship between structure and particle acceleration. The phenomenological distinction between quasi-parallel and quasi-perpendicular shocks that has emerged from bow shock research; present efforts to extend this work to interplanetary shocks; theories of particle acceleration by shocks; and particle acceleration to shock structures using multiple fluid models were discussed.

Application of Intel Many Integrated Core (MIC) architecture to the Yonsei University planetary boundary layer scheme in Weather Research and Forecasting model

NASA Astrophysics Data System (ADS)

Huang, Melin; Huang, Bormin; Huang, Allen H.

2014-10-01

The Weather Research and Forecasting (WRF) model provided operational services worldwide in many areas and has linked to our daily activity, in particular during severe weather events. The scheme of Yonsei University (YSU) is one of planetary boundary layer (PBL) models in WRF. The PBL is responsible for vertical sub-grid-scale fluxes due to eddy transports in the whole atmospheric column, determines the flux profiles within the well-mixed boundary layer and the stable layer, and thus provide atmospheric tendencies of temperature, moisture (including clouds), and horizontal momentum in the entire atmospheric column. The YSU scheme is very suitable for massively parallel computation as there are no interactions among horizontal grid points. To accelerate the computation process of the YSU scheme, we employ Intel Many Integrated Core (MIC) Architecture as it is a multiprocessor computer structure with merits of efficient parallelization and vectorization essentials. Our results show that the MIC-based optimization improved the performance of the first version of multi-threaded code on Xeon Phi 5110P by a factor of 2.4x. Furthermore, the same CPU-based optimizations improved the performance on Intel Xeon E5-2603 by a factor of 1.6x as compared to the first version of multi-threaded code.

A transient analysis of frost formation on a parallel plate evaporator

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

Martinez-Frias, J.; Aceves, S.M.; Hernandez-Guerrero, A.

1996-12-31

This paper presents the development of a transient model for evaluating frost formation on a parallel plate evaporator for heat pump applications. The model treats the frost layer as a porous substance, and applies the equations of conservation of mass, momentum and energy to calculate the growth and densification of the frost layer. Empirical correlations for thermal conductivity and tortuosity as a function of density are incorporated from previous studies. Frost growth is calculated as a function of time, Reynolds number, longitudinal location, plate temperature, and ambient air temperature and humidity. The main assumptions are: ideal gas behavior for airmore » and water vapor, uniform frost density and thermal conductivity across the thickness of the frost layer; and quasi-steady conditions during the whole process. The mathematical model is validated by comparing the predicted values of frost thickness and frost density with results obtained in recent experimental studies. A good agreement was obtained in the comparison. The frost formation model calculates pressure drop and heat transfer resistance that result from the existence of the frost layer, and it can therefore be incorporated into a heat pump model to evaluate performance losses due to frosting as a function of weather conditions and time of operation since the last evaporator defrost.« less

Neutron Powder Diffraction Study on the Magnetic Structure of NdPd 5 Al 2

DOE PAGES

Metoki, Naoto; Yamauchi, Hiroki; Kitazawa, Hideaki; ...

2017-02-24

The magnetic structure of NdPd 5Al 2 has been studied by neutron powder diffraction. Here, we observed the magnetic reflections with the modulation vector q=(1/2,0,0)q=(1/2,0,0) below the ordering temperature T N. We also found a collinear magnetic structure with a Nd moment of 2.7(3) μB at 0.5 K parallel to the c-axis, where the ferromagnetically ordered a-planes stack with a four-Nd-layer period having a ++-- sequence along the a-direction with the distance between adjacent Nd layers equal to a/2 (magnetic space group P anma). This “stripe”-like modulation is very similar to that in CePd 5Al 2 with q=(0.235,0.235,0)q=(0.235,0.235,0) with themore » Ce moment parallel to the c-axis. These structures with in-plane modulation are a consequence of the two-dimensional nature of the Fermi surface topology in this family, originating from the unique crystal structure with a very long tetragonal unit cell and a large distance of >7 Å between the rare-earth layers separated by two Pd and one Al layers.« less

Crystal structure of dimanganese(II) zinc bis­[ortho­phosphate(V)] monohydrate

PubMed Central

Alhakmi, Ghaleb; Assani, Abderrazzak; Saadi, Mohamed; El Ammari, Lahcen

2015-01-01

The title compound, Mn2Zn(PO4)2·H2O, was obtained under hydro­thermal conditions. The structure is isotypic with other transition metal phosphates of the type M 3− xM′x(PO4)2·H2O, but shows no statistical disorder of the three metallic sites. The principal building units are distorted [MnO6] and [MnO5(H2O)] octa­hedra, a distorted [ZnO5] square pyramid and two regular PO4 tetra­hedra. The connection of the polyhedra leads to a framework structure. Two types of layers parallel to (-101) can be distinguished in this framework. One layer contains [Zn2O8] dimers linked to PO4 tetra­hedra via common edges. The other layer is more corrugated and contains [Mn2O8(H2O)2] dimers and [MnO6] octa­hedra linked together by common edges. The PO4 tetra­hedra link the two types of layers into a framework structure with channels parallel to [101]. The H atoms of the water mol­ecules point into the channels and form O—H⋯O hydrogen bonds (one of which is bifurcated) with framework O atoms across the channels. PMID:25878806

Ion irradiation effects on a magnetic Si/Ni/Si trilayer and lateral magnetic-nonmagnetic multistrip patterning by focused ion beam

NASA Astrophysics Data System (ADS)

Dev, B. N.; Banu, Nasrin; Fassbender, J.; Grenzer, J.; Schell, N.; Bischoff, L.; Groetzschel, R.; McCord, J.

2017-10-01

Fabrication of a multistrip magnetic/nonmagnetic structure in a thin sandwiched Ni layer [Si(5 nm)/Ni(15 nm)/Si] by a focused ion beam (FIB) irradiation has been attempted. A control experiment was initially performed by irradiation with a standard 30 keV Ga ion beam at various fluences. Analyses were carried out by Rutherford backscattering spectrometry, X-ray reflectivity, magnetooptical Kerr effect (MOKE) measurements and MOKE microscopy. With increasing ion fluence, the coercivity as well as Kerr rotation decreases. A threshold ion fluence has been identified, where ferromagnetism of the Ni layer is lost at room temperature and due to Si incorporation into the Ni layer, a Ni0.68Si0.32 alloy layer is formed. This fluence was used in FIB irradiation of parallel 50 nm wide stripes, leaving 1 µm wide unirradiated stripes in between. MOKE microscopy on this FIB-patterned sample has revealed interacting magnetic domains across several stripes. Considering shape anisotropy effects, which would favour an alignment of magnetization parallel to the stripe axis, the opposite behaviour is observed. Magneto-elastic effects introducing a stress-induced anisotropy component oriented perpendicular to the stripe axis are the most plausible explanation for the observed behaviour.

Neutron Powder Diffraction Study on the Magnetic Structure of NdPd 5 Al 2

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

Metoki, Naoto; Yamauchi, Hiroki; Kitazawa, Hideaki

The magnetic structure of NdPd 5Al 2 has been studied by neutron powder diffraction. Here, we observed the magnetic reflections with the modulation vector q=(1/2,0,0)q=(1/2,0,0) below the ordering temperature T N. We also found a collinear magnetic structure with a Nd moment of 2.7(3) μB at 0.5 K parallel to the c-axis, where the ferromagnetically ordered a-planes stack with a four-Nd-layer period having a ++-- sequence along the a-direction with the distance between adjacent Nd layers equal to a/2 (magnetic space group P anma). This “stripe”-like modulation is very similar to that in CePd 5Al 2 with q=(0.235,0.235,0)q=(0.235,0.235,0) with themore » Ce moment parallel to the c-axis. These structures with in-plane modulation are a consequence of the two-dimensional nature of the Fermi surface topology in this family, originating from the unique crystal structure with a very long tetragonal unit cell and a large distance of >7 Å between the rare-earth layers separated by two Pd and one Al layers.« less

Transfer of line radiation in differentially expanding atmospheres. VI The plane parallel atmosphere with expanding and contracting regions

NASA Technical Reports Server (NTRS)

Noerdlinger, P. D.

1981-01-01

The non-LTE radiative transfer problem for a two level atom with complete redistribution over a Doppler profile is solved for a plane parallel slab (overlying a radiating photosphere) that has a velocity field which rises symmetrically from zero at either face to a central maximum. Since the velocity gradient reverses, distant layers of the slab become coupled by radiation that jumps intervening layers. The Feautrier method is used, but an iterative variant is also employed as a check in cases where poorly conditioned matrices are encountered. Approximations are developed to explain some of the principal features. It is found that the source function S tends to have two plateaus with values near 2/3 I sub 0 and 1/3 I sub 0, where I sub 0 is the photospheric continuum incident from below; the larger value lies nearer the photosphere. The upper layers sometimes exhibit a rise in S owing to interconnection by radiation to the base. It is noted that the radiation force is largest at the two faces and the midplane. Some line profiles are found to have unusually steep absorptions at rest frequency because of the low excitation in the uppermost, stationary layers.

Boundary-Layer Bypass Transition Over Large-Scale Bodies

DTIC Science & Technology

2016-12-16

shape of the streamwise velocity profile compared to the flat- plate boundary layer. The research showed that the streamwise wavenumber plays a key role...many works on the suppression of the transitional boundary layer. Most of the results in the literature are for the flat- plate boundary layer but the...behaviour of the velocity and pressure changes with the curvature. This work aims to extend the results of the flat- plate boundary layer to a Rankine

Spatial extent and dissipation of the deep chlorophyll layer in Lake Ontario during the Lake Ontario lower foodweb assessment, 2003 and 2008

USGS Publications Warehouse

Watkins, J. M.; Weidel, Brian M.; Rudstam, L. G.; Holek, K. T.

2014-01-01

Increasing water clarity in Lake Ontario has led to a vertical redistribution of phytoplankton and an increased importance of the deep chlorophyll layer in overall primary productivity. We used in situ fluorometer profiles collected in lakewide surveys of Lake Ontario in 2008 to assess the spatial extent and intensity of the deep chlorophyll layer. In situ fluorometer data were corrected with extracted chlorophyll data using paired samples from Lake Ontario collected in August 2008. The deep chlorophyll layer was present offshore during the stratified conditions of late July 2008 with maximum values from 4-13 μg l-1 corrected chlorophyll a at 10 to 17 m depth within the metalimnion. Deep chlorophyll layer was closely associated with the base of the thermocline and a subsurface maximum of dissolved oxygen, indicating the feature's importance as a growth and productivity maximum. Crucial to the deep chlorophyll layer formation, the photic zone extended deeper than the surface mixed layer in mid-summer. The layer extended through most of the offshore in July 2008, but was not present in the easternmost transect that had a deeper surface mixed layer. By early September 2008, the lakewide deep chlorophyll layer had dissipated. A similar formation and dissipation was observed in the lakewide survey of Lake Ontario in 2003.

SPM oxidation and parallel writing on zirconium nitride thin films

NASA Astrophysics Data System (ADS)

Farkas, N.; Comer, J. R.; Zhang, G.; Evans, E. A.; Ramsier, R. D.; Dagata, J. A.

2005-07-01

Systematic investigation of the SPM oxidation process of sputter-deposited ZrN thin films is reported. During the intrinsic part of the oxidation, the density of the oxide increases until the total oxide thickness is approximately twice the feature height. Further oxide growth is sustainable as the system undergoes plastic flow followed by delamination from the ZrN-silicon interface keeping the oxide density constant. ZrN exhibits superdiffusive oxidation kinetics in these single tip SPM studies. We extend this work to the fabrication of parallel oxide patterns 70 nm in height covering areas in the square centimeter range. This simple, quick, and well-controlled parallel nanolithographic technique has great potential for biomedical template fabrication.

The Equivalent Electrokinetic Circuit Model of Ion Concentration Polarization Layer: Electrical Double Layer, Extended Space Charge and Electro-convection

NASA Astrophysics Data System (ADS)

Cho, Inhee; Huh, Keon; Kwak, Rhokyun; Lee, Hyomin; Kim, Sung Jae

2016-11-01

The first direct chronopotentiometric measurement was provided to distinguish the potential difference through the extended space charge (ESC) layer which is formed with the electrical double layer (EDL) near a perm-selective membrane. From this experimental result, the linear relationship was obtained between the resistance of ESC and the applied current density. Furthermore, we observed the step-wise distributions of relaxation time at the limiting current regime, confirming the existence of ESC capacitance other than EDL's. In addition, we proposed the equivalent electrokinetic circuit model inside ion concentration polarization (ICP) layer under rigorous consideration of EDL, ESC and electro-convection (EC). In order to elucidate the voltage configuration in chronopotentiometric measurement, the EC component was considered as the "dependent voltage source" which is serially connected to the ESC layer. This model successfully described the charging behavior of the ESC layer with or without EC, where both cases determined each relaxation time, respectively. Finally, we quantitatively verified their values utilizing the Poisson-Nernst-Planck equations. Therefore, this unified circuit model would provide a key insight of ICP system and potential energy-efficient applications.

Tetra­ethyl­ammonium dicyanido(5,10,15,20-tetra­phenyl­porphyrinato)ferrate(III) di­chloro­methane monosolvate

PubMed Central

Kassenova, Nazira; Hietsoi, Oleksandr; Yerkassov, Rakhmetulla; Shatruk, Michael

2013-01-01

The title compound, (C8H20N)[Fe(C44H28N4)(CN)2]·CH2Cl2 or (Et4N)[Fe(TPP)(CN)2], was recrystallized from di­chloro­methane–diethyl ether. The compound crystallizes with the two unique halves of the FeIII porphyrinato complex, one tetra­ethyl­ammonium cation and one inter­stitial di­chloro­methane mol­ecule within the asymmetric unit. Both anionic FeIII complexes exhibit inversion symmetry. Both the cation and the solvent mol­ecules show positional disorder. The cation is disordered over two sets of sites with an occupancy ratio of 0.710 (3):0.290 (3); the solvent mol­ecule is disordered over three positions with a 0.584 (6):0.208 (3):0.202 (5) ratio. The crystal packing features columns of [Fe(TPP)(CN)2]− anions that propagate along [001]. The columns further pack into layers that are parallel to (011) and also include the Et4N+ cations. The inter­stitial CH2Cl2 mol­ecules appear in the inter­layer space. This complex may serve as a useful precursor for the assembly of multinuclear and extended CN-bridged complexes for the design of single-mol­ecule and single-chain magnets, respectively. PMID:24109282

Numerically stable, scalable formulas for parallel and online computation of higher-order multivariate central moments with arbitrary weights

DOE PAGES

Pebay, Philippe; Terriberry, Timothy B.; Kolla, Hemanth; ...

2016-03-29

Formulas for incremental or parallel computation of second order central moments have long been known, and recent extensions of these formulas to univariate and multivariate moments of arbitrary order have been developed. Such formulas are of key importance in scenarios where incremental results are required and in parallel and distributed systems where communication costs are high. We survey these recent results, and improve them with arbitrary-order, numerically stable one-pass formulas which we further extend with weighted and compound variants. We also develop a generalized correction factor for standard two-pass algorithms that enables the maintenance of accuracy over nearly the fullmore » representable range of the input, avoiding the need for extended-precision arithmetic. We then empirically examine algorithm correctness for pairwise update formulas up to order four as well as condition number and relative error bounds for eight different central moment formulas, each up to degree six, to address the trade-offs between numerical accuracy and speed of the various algorithms. Finally, we demonstrate the use of the most elaborate among the above mentioned formulas, with the utilization of the compound moments for a practical large-scale scientific application.« less

Scalable domain decomposition solvers for stochastic PDEs in high performance computing

DOE PAGES

Desai, Ajit; Khalil, Mohammad; Pettit, Chris; ...

2017-09-21

Stochastic spectral finite element models of practical engineering systems may involve solutions of linear systems or linearized systems for non-linear problems with billions of unknowns. For stochastic modeling, it is therefore essential to design robust, parallel and scalable algorithms that can efficiently utilize high-performance computing to tackle such large-scale systems. Domain decomposition based iterative solvers can handle such systems. And though these algorithms exhibit excellent scalabilities, significant algorithmic and implementational challenges exist to extend them to solve extreme-scale stochastic systems using emerging computing platforms. Intrusive polynomial chaos expansion based domain decomposition algorithms are extended here to concurrently handle high resolutionmore » in both spatial and stochastic domains using an in-house implementation. Sparse iterative solvers with efficient preconditioners are employed to solve the resulting global and subdomain level local systems through multi-level iterative solvers. We also use parallel sparse matrix–vector operations to reduce the floating-point operations and memory requirements. Numerical and parallel scalabilities of these algorithms are presented for the diffusion equation having spatially varying diffusion coefficient modeled by a non-Gaussian stochastic process. Scalability of the solvers with respect to the number of random variables is also investigated.« less

Scalable domain decomposition solvers for stochastic PDEs in high performance computing

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

Desai, Ajit; Khalil, Mohammad; Pettit, Chris

Stochastic spectral finite element models of practical engineering systems may involve solutions of linear systems or linearized systems for non-linear problems with billions of unknowns. For stochastic modeling, it is therefore essential to design robust, parallel and scalable algorithms that can efficiently utilize high-performance computing to tackle such large-scale systems. Domain decomposition based iterative solvers can handle such systems. And though these algorithms exhibit excellent scalabilities, significant algorithmic and implementational challenges exist to extend them to solve extreme-scale stochastic systems using emerging computing platforms. Intrusive polynomial chaos expansion based domain decomposition algorithms are extended here to concurrently handle high resolutionmore » in both spatial and stochastic domains using an in-house implementation. Sparse iterative solvers with efficient preconditioners are employed to solve the resulting global and subdomain level local systems through multi-level iterative solvers. We also use parallel sparse matrix–vector operations to reduce the floating-point operations and memory requirements. Numerical and parallel scalabilities of these algorithms are presented for the diffusion equation having spatially varying diffusion coefficient modeled by a non-Gaussian stochastic process. Scalability of the solvers with respect to the number of random variables is also investigated.« less

Remapping HELENA to incompressible plasma rotation parallel to the magnetic field

NASA Astrophysics Data System (ADS)

Poulipoulis, G.; Throumoulopoulos, G. N.; Konz, C.

2016-07-01

Plasma rotation in connection to both zonal and mean (equilibrium) flows can play a role in the transitions to the advanced confinement regimes in tokamaks, as the L-H transition and the formation of internal transport barriers (ITBs). For incompressible rotation, the equilibrium is governed by a generalised Grad-Shafranov (GGS) equation and a decoupled Bernoulli-type equation for the pressure. For parallel flow, the GGS equation can be transformed to one identical in form with the usual Grad-Shafranov equation. In the present study on the basis of the latter equation, we have extended HELENA, an equilibrium fixed boundary solver. The extended code solves the GGS equation for a variety of the two free-surface-function terms involved for arbitrary Alfvén Mach number and density functions. We have constructed diverted-boundary equilibria pertinent to ITER and examined their characteristics, in particular, as concerns the impact of rotation on certain equilibrium quantities. It turns out that the rotation and its shear affect noticeably the pressure and toroidal current density with the impact on the current density being stronger in the parallel direction than in the toroidal one.

Celestial illusions and ancient astronomers: Aristarchus and Eratosthenes

NASA Astrophysics Data System (ADS)

Papathomas, Thomas V.

2005-03-01

When the moon is half, one would expect that a line starting from the moon"s center and being perpendicular to the "shadow diameter" would, if extended, go through the center of the light source, namely, the sun. It turns out that, when the sun is visible, this extended line appears to aim significantly above the sun, which is the essence of the "half-moon illusion". The explanation advanced here is that this is not an optical illusion; instead, it can be explained by the relative sizes and distances of the earth, moon, and sun, and it hinges on the fact that the sunrays are nearly parallel with respect to the earth-moon system. It turns out that the ancients knew and used this near-parallelism of the sunrays. Eratosthenes, for example, used a simple but ingenious scheme to obtain a good estimate of the earth"s circumference. An interesting question is: How did the ancients arrive at the conclusion that the sunrays are nearly parallel? This was probably a corollary, based on the immense size of the sun and its huge distance from the earth, as estimated by, among others, Aristarchus of Samos by a brilliantly simple method.

Extended MHD modeling of tearing-driven magnetic relaxation

NASA Astrophysics Data System (ADS)

Sauppe, J. P.; Sovinec, C. R.

2017-05-01

Discrete relaxation events in reversed-field pinch relevant configurations are investigated numerically with nonlinear extended magnetohydrodynamic (MHD) modeling, including the Hall term in Ohm's law and first-order ion finite Larmor radius effects. Results show variability among relaxation events, where the Hall dynamo effect may help or impede the MHD dynamo effect in relaxing the parallel current density profile. The competitive behavior arises from multi-helicity conditions where the dominant magnetic fluctuation is relatively small. The resulting changes in parallel current density and parallel flow are aligned in the core, consistent with experimental observations. The analysis of simulation results also confirms that the force density from fluctuation-induced Reynolds stress arises subsequent to the drive from the fluctuation-induced Lorentz force density. Transport of the momentum density is found to be dominated by the fluctuation-induced Maxwell stress over most of the cross section with viscous and gyroviscous contributions being large in the edge region. The findings resolve a discrepancy with respect to the relative orientation of current density and flow relaxation, which had not been realized or investigated in King et al. [Phys. Plasmas 19, 055905 (2012)], where only the magnitude of flow relaxation is actually consistent with experimental results.

Influence of Thermal Anisotropy on Equilibrium Stellarator Beta Limits

NASA Astrophysics Data System (ADS)

Bechtel, T. A.; Hegna, C. C.; Sovinec, C. R.

2017-10-01

The effect of anisotropic heat conduction on the upper beta limit of stellarator plasmas is studied using the nonlinear, extended MHD code NIMROD. The configuration under investigation is an l=2, M=10 torsatron with vacuum rotational transform near unity. Finite-beta plasmas are created using a volumetric heating source and temperature dependent resistivity; modeled with 22 stellarator symmetric (integer multiples of M) toroidal modes. Extended MHD simulations are then performed to generate steady state solutions that represent 3D equilibria. With increased heating, Shafranov shifts occur, and the associated break up of edge magnetic surfaces limits the achievable beta. Due to the presence of finite parallel heat conduction, pressure profiles can exist in regions of magnetic stochasticity. Here, we present results of independently varying the parallel and perpendicular thermal anisotropy. In particular, simulations show that the attained stored energy is a function of the magnitude of parallel and perpendicular thermal conduction for a given heat source, indicating that equilibrium beta limits are sensitive to anisotropic transport properties. Preliminary studies of MHD stability with non-stellarator symmetric modes, near the highest achievable beta, are also presented. Research supported by US DOE under Grant No. DE-FG02-99ER54546.

Parallel software support for computational structural mechanics

NASA Technical Reports Server (NTRS)

Jordan, Harry F.

1987-01-01

The application of the parallel programming methodology known as the Force was conducted. Two application issues were addressed. The first involves the efficiency of the implementation and its completeness in terms of satisfying the needs of other researchers implementing parallel algorithms. Support for, and interaction with, other Computational Structural Mechanics (CSM) researchers using the Force was the main issue, but some independent investigation of the Barrier construct, which is extremely important to overall performance, was also undertaken. Another efficiency issue which was addressed was that of relaxing the strong synchronization condition imposed on the self-scheduled parallel DO loop. The Force was extended by the addition of logical conditions to the cases of a parallel case construct and by the inclusion of a self-scheduled version of this construct. The second issue involved applying the Force to the parallelization of finite element codes such as those found in the NICE/SPAR testbed system. One of the more difficult problems encountered is the determination of what information in COMMON blocks is actually used outside of a subroutine and when a subroutine uses a COMMON block merely as scratch storage for internal temporary results.

Parallel algorithms for mapping pipelined and parallel computations

NASA Technical Reports Server (NTRS)

Nicol, David M.

1988-01-01

Many computational problems in image processing, signal processing, and scientific computing are naturally structured for either pipelined or parallel computation. When mapping such problems onto a parallel architecture it is often necessary to aggregate an obvious problem decomposition. Even in this context the general mapping problem is known to be computationally intractable, but recent advances have been made in identifying classes of problems and architectures for which optimal solutions can be found in polynomial time. Among these, the mapping of pipelined or parallel computations onto linear array, shared memory, and host-satellite systems figures prominently. This paper extends that work first by showing how to improve existing serial mapping algorithms. These improvements have significantly lower time and space complexities: in one case a published O(nm sup 3) time algorithm for mapping m modules onto n processors is reduced to an O(nm log m) time complexity, and its space requirements reduced from O(nm sup 2) to O(m). Run time complexity is further reduced with parallel mapping algorithms based on these improvements, which run on the architecture for which they create the mappings.

The mean and turbulent flow structure of a weak hydraulic jump

NASA Astrophysics Data System (ADS)

Misra, S. K.; Kirby, J. T.; Brocchini, M.; Veron, F.; Thomas, M.; Kambhamettu, C.

2008-03-01

The turbulent air-water interface and flow structure of a weak, turbulent hydraulic jump are analyzed in detail using particle image velocimetry measurements. The study is motivated by the need to understand the detailed dynamics of turbulence generated in steady spilling breakers and the relative importance of the reverse-flow and breaker shear layer regions with attention to their topology, mean flow, and turbulence structure. The intermittency factor derived from turbulent fluctuations of the air-water interface in the breaker region is found to fit theoretical distributions of turbulent interfaces well. A conditional averaging technique is used to calculate ensemble-averaged properties of the flow. The computed mean velocity field accurately satisfies mass conservation. A thin, curved shear layer oriented parallel to the surface is responsible for most of the turbulence production with the turbulence intensity decaying rapidly away from the toe of the breaker (location of largest surface curvature) with both increasing depth and downstream distance. The reverse-flow region, localized about the ensemble-averaged free surface, is characterized by a weak downslope mean flow and entrainment of water from below. The Reynolds shear stress is negative in the breaker shear layer, which shows that momentum diffuses upward into the shear layer from the flow underneath, and it is positive just below the mean surface indicating a downward flux of momentum from the reverse-flow region into the shear layer. The turbulence structure of the breaker shear layer resembles that of a mixing layer originating from the toe of the breaker, and the streamwise variations of the length scale and growth rate are found to be in good agreement with observed values in typical mixing layers. All evidence suggests that breaking is driven by a surface-parallel adverse pressure gradient and a streamwise flow deceleration at the toe of the breaker. Both effects force the shear layer to thicken rapidly, thereby inducing a sharp free surface curvature change at the toe.

Low voltage solid-state lateral coloration electrochromic device

DOEpatents

Tracy, C.E.; Benson, D.K.; Ruth, M.R.

1984-12-21

A solid-state transition metal oxide device comprising a plurality of layers having a predisposed orientation including an electrochromic oxide layer. Conductive material including anode and cathode contacts is secured to the device. Coloration is actuated within the electrochromic oxide layer after the application of a predetermined potential between the contacts. The coloration action is adapted to sweep or dynamically extend across the length of the electrochromic oxide layer.

Computational strategies for three-dimensional flow simulations on distributed computer systems. Ph.D. Thesis Semiannual Status Report, 15 Aug. 1993 - 15 Feb. 1994

NASA Technical Reports Server (NTRS)

Weed, Richard Allen; Sankar, L. N.

1994-01-01

An increasing amount of research activity in computational fluid dynamics has been devoted to the development of efficient algorithms for parallel computing systems. The increasing performance to price ratio of engineering workstations has led to research to development procedures for implementing a parallel computing system composed of distributed workstations. This thesis proposal outlines an ongoing research program to develop efficient strategies for performing three-dimensional flow analysis on distributed computing systems. The PVM parallel programming interface was used to modify an existing three-dimensional flow solver, the TEAM code developed by Lockheed for the Air Force, to function as a parallel flow solver on clusters of workstations. Steady flow solutions were generated for three different wing and body geometries to validate the code and evaluate code performance. The proposed research will extend the parallel code development to determine the most efficient strategies for unsteady flow simulations.

NMR of thin layers using a meanderline surface coil

DOEpatents

Cowgill, Donald F.

2001-01-01

A miniature meanderline sensor coil which extends the capabilities of nuclear magnetic resonance (NMR) to provide analysis of thin planar samples and surface layer geometries. The sensor coil allows standard NMR techniques to be used to examine thin planar (or curved) layers, extending NMRs utility to many problems of modern interest. This technique can be used to examine contact layers, non-destructively depth profile into films, or image multiple layers in a 3-dimensional sense. It lends itself to high resolution NMR techniques of magic angle spinning and thus can be used to examine the bonding and electronic structure in layered materials or to observe the chemistry associated with aging coatings. Coupling this sensor coil technology with an arrangement of small magnets will produce a penetrator probe for remote in-situ chemical analysis of groundwater or contaminant sediments. Alternatively, the sensor coil can be further miniaturized to provide sub-micron depth resolution within thin films or to orthoscopically examine living tissue. This thin-layer NMR technique using a stationary meanderline coil in a series-resonant circuit has been demonstrated and it has been determined that the flat meanderline geometry has about he same detection sensitivity as a solenoidal coil, but is specifically tailored to examine planar material layers, while avoiding signals from the bulk.

Dispersoid separation method and apparatus

DOEpatents

Winsche, Warren E.

1980-01-01

Improved separation of heavier material from a dispersoid of gas and heavier material entrained therein is taught by the method of this invention which advantageously uses apparatus embodied in an inertial separator having rotary partition means comprising wall members dividing a housing into a plurality of axially-extending through passages arranged in parallel. Simultaneously with the helical transit of a moving stream of the dispersoid through the parallel arrangement of axially-extending through passages at a constant angular velocity, the heavier material is driven radially to the collecting surfaces of the rotational wall members where it is collected while the wall members are rotating at the same angular velocity as the moving stream. The plurality of wall members not only provides an increased area of collecting surfaces but the positioning of each of the wall members according to the teaching of this invention also results in a shortened time-of-flight to the collecting surfaces.

Method for adhering a coating to a substrate structure

DOEpatents

Taxacher, Glenn Curtis; Crespo, Andres Garcia; Roberts, III, Herbert Chidsey

2015-02-17

A method for adhering a coating to a substrate structure comprises selecting a substrate structure having an outer surface oriented substantially parallel to a direction of radial stress, modifying the outer surface to provide a textured region having steps to adhere a coating thereto, and applying a coating to extend over at least a portion of the textured region, wherein the steps are oriented substantially perpendicular to the direction of radial stress to resist deformation of the coating relative to the substrate structure. A rotating component comprises a substrate structure having an outer surface oriented substantially parallel to a direction of radial stress. The outer surface defines a textured region having steps to adhere a coating thereto, and a coating extends over at least a portion of the textured region. The steps are oriented substantially perpendicular to the direction of radial stress to resist creep.

Applying the Extended Parallel Process Model to workplace safety messages.

PubMed

Basil, Michael; Basil, Debra; Deshpande, Sameer; Lavack, Anne M

2013-01-01

The extended parallel process model (EPPM) proposes fear appeals are most effective when they combine threat and efficacy. Three studies conducted in the workplace safety context examine the use of various EPPM factors and their effects, especially multiplicative effects. Study 1 was a content analysis examining the use of EPPM factors in actual workplace safety messages. Study 2 experimentally tested these messages with 212 construction trainees. Study 3 replicated this experiment with 1,802 men across four English-speaking countries-Australia, Canada, the United Kingdom, and the United States. The results of these three studies (1) demonstrate the inconsistent use of EPPM components in real-world work safety communications, (2) support the necessity of self-efficacy for the effective use of threat, (3) show a multiplicative effect where communication effectiveness is maximized when all model components are present (severity, susceptibility, and efficacy), and (4) validate these findings with gory appeals across four English-speaking countries.

Laser weld jig

DOEpatents

Van Blarigan, Peter; Haupt, David L.

1982-01-01

A system is provided for welding a workpiece (10, FIG. 1) along a predetermined weld line (12) that may be of irregular shape, which includes the step of forming a lip (32) on the workpiece to extend parallel to the weld line, and moving the workpiece by engaging the lip between a pair of rotatable members (34, 36). Rotation of one of the members at a constant speed, causes the workpiece to move so that all points on the weld line sequentially pass a fixed point in space (17) at a constant speed, so that a laser welding beam can be directed at that fixed point to form a weld along the weld line. The workpiece can include a reuseable jig (24) forming the lip, and with the jig constructed to detachably hold parts (22, 20) to be welded at a position wherein the weld line of the parts extends parallel to the lip on the jig.

Orientation dependence of the dislocation microstructure in compressed body-centered cubic molybdenum

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

Wang, S.; Wang, M.P.; Chen, C., E-mail: chench011-33@163.com

2014-05-01

The orientation dependence of the deformation microstructure has been investigated in commercial pure molybdenum. After deformation, the dislocation boundaries of compressed molybdenum can be classified, similar to that in face-centered cubic metals, into three types: dislocation cells (Type 2), and extended planar boundaries parallel to (Type 1) or not parallel to (Type 3) a (110) trace. However, it shows a reciprocal relationship between face-centered cubic metals and body-centered cubic metals on the orientation dependence of the deformation microstructure. The higher the strain, the finer the microstructure is and the smaller the inclination angle between extended planar boundaries and the compressionmore » axis is. - Highlights: • A reciprocal relationship between FCC metals and BCC metals is confirmed. • The dislocation boundaries can be classified into three types in compressed Mo. • The dislocation characteristic of different dislocation boundaries is different.« less

Characterization of BN rich layer on ammonia treated Nextel{trademark}312 fibers

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

Khasgiwale, N.R.; Butler, E.P.; Tsakalakos, L.

A BN rich layer grown on Nextel{trademark}312 fibers by appropriate ammonia treatments was evaluated using various complimentary techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM)/Parallel Electron Energy Loss Spectroscopy (PEELS in TEM). Three different ammonia treatments were studied. Ammonia treatment resulted in crystallization of the Nextel{trademark}312 fiber. The BN rich surface layer formed due to ammonia treatment was clearly detected in XPS and PEELS both before and after oxidation. The layer thickness was estimated to be between 5--10 nm. The layer was stable after oxidation treatment at 600 C formore » 100 hours. High resolution TEM observations of the fiber surface revealed a variable BN rich layer thickness. Patches of turbostratic BN were observed under certain conditions, however mostly the layer appeared to be amorphous.« less

Directed Self-Assembly on Photo-Crosslinked Polystyrene Sub-Layers: Nanopattern Uniformity and Orientation

PubMed Central

Koh, Haeng-Deog; Kim, Mi-Jeong

2016-01-01

A photo-crosslinked polystyrene (PS) thin film is investigated as a potential guiding sub-layer for polystyrene-block-poly (methyl methacrylate) block copolymer (BCP) cylindrical nanopattern formation via topographic directed self-assembly (DSA). When compared to a non-crosslinked PS brush sub-layer, the photo-crosslinked PS sub-layer provided longer correlation lengths of the BCP nanostructure, resulting in a highly uniform DSA nanopattern with a low number of BCP dislocation defects. Depending on the thickness of the sub-layer used, parallel or orthogonal orientations of DSA nanopattern arrays were obtained that covered the entire surface of patterned Si substrates, including both trench and mesa regions. The design of DSA sub-layers and guide patterns, such as hardening the sub-layer by photo-crosslinking, nano-structuring on mesas, the relation between trench/mesa width, and BCP equilibrium period, were explored with a view to developing defect-reduced DSA lithography technology. PMID:28773768

The Automatic Parallelisation of Scientific Application Codes Using a Computer Aided Parallelisation Toolkit

NASA Technical Reports Server (NTRS)

Ierotheou, C.; Johnson, S.; Leggett, P.; Cross, M.; Evans, E.; Jin, Hao-Qiang; Frumkin, M.; Yan, J.; Biegel, Bryan (Technical Monitor)

2001-01-01

The shared-memory programming model is a very effective way to achieve parallelism on shared memory parallel computers. Historically, the lack of a programming standard for using directives and the rather limited performance due to scalability have affected the take-up of this programming model approach. Significant progress has been made in hardware and software technologies, as a result the performance of parallel programs with compiler directives has also made improvements. The introduction of an industrial standard for shared-memory programming with directives, OpenMP, has also addressed the issue of portability. In this study, we have extended the computer aided parallelization toolkit (developed at the University of Greenwich), to automatically generate OpenMP based parallel programs with nominal user assistance. We outline the way in which loop types are categorized and how efficient OpenMP directives can be defined and placed using the in-depth interprocedural analysis that is carried out by the toolkit. We also discuss the application of the toolkit on the NAS Parallel Benchmarks and a number of real-world application codes. This work not only demonstrates the great potential of using the toolkit to quickly parallelize serial programs but also the good performance achievable on up to 300 processors for hybrid message passing and directive-based parallelizations.

A compositional reservoir simulator on distributed memory parallel computers

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

Rame, M.; Delshad, M.

1995-12-31

This paper presents the application of distributed memory parallel computes to field scale reservoir simulations using a parallel version of UTCHEM, The University of Texas Chemical Flooding Simulator. The model is a general purpose highly vectorized chemical compositional simulator that can simulate a wide range of displacement processes at both field and laboratory scales. The original simulator was modified to run on both distributed memory parallel machines (Intel iPSC/960 and Delta, Connection Machine 5, Kendall Square 1 and 2, and CRAY T3D) and a cluster of workstations. A domain decomposition approach has been taken towards parallelization of the code. Amore » portion of the discrete reservoir model is assigned to each processor by a set-up routine that attempts a data layout as even as possible from the load-balance standpoint. Each of these subdomains is extended so that data can be shared between adjacent processors for stencil computation. The added routines that make parallel execution possible are written in a modular fashion that makes the porting to new parallel platforms straight forward. Results of the distributed memory computing performance of Parallel simulator are presented for field scale applications such as tracer flood and polymer flood. A comparison of the wall-clock times for same problems on a vector supercomputer is also presented.« less

Leading-edge effects on boundary-layer receptivity

NASA Technical Reports Server (NTRS)

Gatski, Thomas B.; Kerschen, Edward J.

1990-01-01

Numerical calculations are presented for the incompressible flow over a parabolic cylinder. The computational domain extends from a region upstream of the body downstream to the region where the Blasius boundary-layer solution holds. A steady mean flow solution is computed and the results for the scaled surface vorticity, surface pressure and displacement thickness are compared to previous studies. The unsteady problem is then formulated as a perturbation solution starting with and evolving from the mean flow. The response to irrotational time harmonic pulsation of the free-stream is examined. Results for the initial development of the velocity profile and displacement thickness are presented. These calculations will be extended to later times to investigate the initiation of instability waves within the boundary-layer.

A description of electron heating with an electrostatic potential jump in a parallel, collisionless, fire hose shock

NASA Technical Reports Server (NTRS)

Ellison, Donald C.; Jones, Frank C.

1988-01-01

The electron heating required if protons scatter elastically in a parallel, collisionless shock is calculated. Near-elastic proton scattering off large amplitude background magnetic field fluctuations might be expected if the waves responsible for the shock dissipation are generated by the fire hose instability. The effects of an electrostatic potential jump in the shock layer are included by assuming that the energy lost by protons in traversing the potential jump is converted into electron thermal pressure. It is found that the electron temperature increase is a strong function of the potential jump. Comparison is made to the parallel shock plasma simulation of Quest (1987).

Data Parallel Line Relaxation (DPLR) Code User Manual: Acadia - Version 4.01.1

NASA Technical Reports Server (NTRS)

Wright, Michael J.; White, Todd; Mangini, Nancy

2009-01-01

Data-Parallel Line Relaxation (DPLR) code is a computational fluid dynamic (CFD) solver that was developed at NASA Ames Research Center to help mission support teams generate high-value predictive solutions for hypersonic flow field problems. The DPLR Code Package is an MPI-based, parallel, full three-dimensional Navier-Stokes CFD solver with generalized models for finite-rate reaction kinetics, thermal and chemical non-equilibrium, accurate high-temperature transport coefficients, and ionized flow physics incorporated into the code. DPLR also includes a large selection of generalized realistic surface boundary conditions and links to enable loose coupling with external thermal protection system (TPS) material response and shock layer radiation codes.

Practical calculation of laminar and turbulent bled-off boundary layers

NASA Technical Reports Server (NTRS)

Eppler, R.

1978-01-01

Bleed-off of boundary layer material is shown to be an effective means for reducing drag by conserving the laminar boundary layer and preventing separation of the turbulent boundary layer. The case in which the two effects of bleed-off overlap is examined. Empirical methods are extended to the case of bleed-off. Laminar and turbulent boundary layers are treated simultaneously and the approximation differential equations are solved without an uncertain error. The case without bleed-off is also treated.

Extended OLED operational lifetime through phosphorescent dopant profile management

DOEpatents

Forrest, Stephen R.; Zhang, Yifan

2017-05-30

This disclosure relates, at least in part, an organic light emitting device, which in some embodiments comprises an anode; a cathode; a first emissive layer disposed between the anode and the cathode, the first emissive layer comprising an electron transporting compound and a phosphorescent emissive dopant compound; and wherein the phosphorescent emissive dopant compound has a concentration gradient, in the emissive layer, which varies from the cathode side of the first emissive layer to the anode side of the emissive layer.

Sound-turbulence interaction in transonic boundary layers

NASA Astrophysics Data System (ADS)

Lelostec, Ludovic; Scalo, Carlo; Lele, Sanjiva

2014-11-01

Acoustic wave scattering in a transonic boundary layer is investigated through a novel approach. Instead of simulating directly the interaction of an incoming oblique acoustic wave with a turbulent boundary layer, suitable Dirichlet conditions are imposed at the wall to reproduce only the reflected wave resulting from the interaction of the incident wave with the boundary layer. The method is first validated using the laminar boundary layer profiles in a parallel flow approximation. For this scattering problem an exact inviscid solution can be found in the frequency domain which requires numerical solution of an ODE. The Dirichlet conditions are imposed in a high-fidelity unstructured compressible flow solver for Large Eddy Simulation (LES), CharLESx. The acoustic field of the reflected wave is then solved and the interaction between the boundary layer and sound scattering can be studied.

Thermocapillary convection in two immiscible liquid layers with free surface

NASA Technical Reports Server (NTRS)

Doi, Takao; Koster, Jean N.

1993-01-01

Thermocapillary convection is studied in two immiscible liquid layers with one free surface, one liquid/liquid interface, and differential heating applied parallel to the interfaces. An analytical solution is introduced for infinite horizontal layers. The defining parameter for the flow pattern is lambda, the ratio of the temperature coefficient of the interfacial tension to that of the surface tension. Four different flow patterns exist under zero gravity conditions. 'Halt' conditions which halt the fluid motion in the lower encapsulated liquid layer have been found. A numerical experiment is carried out to study effects of vertical end walls on the double layer convection in a 2D cavity. The halt condition obtained from the analytical study is found to be valid in the limit of small Reynolds numbers. The flow in the encapsulated liquid layer can be suppressed substantially.

Thermal Programmed Desorption of C32 H 66

NASA Astrophysics Data System (ADS)

Cisternas, M.; Del Campo, V.; Cabrera, A. L.; Volkmann, U. G.; Hansen, F. Y.; Taub, H.

2011-03-01

Alkanes are of interest as prototypes for more complex molecules and membranes. In this work we study the desorption kinetics of dotriacontane C32 adsorbed on Si O2 /Si substrate. We combine in our instrument High Resolution Ellipsometry (HRE) and Thermal Programmed Desorption (TPD). C32 monolayers were deposited in high vacuum from a Knudsen cell on the substrate, monitorizing sample thickness in situ with HRE. Film thickness was in the range of up to 100 AA, forming a parallel bilayer and perpendicular C32 layer. The Mass Spectrometer (RGA) of the TPD section was detecting the shift of the desorption peaks at different heating rates applied to the sample. The mass registered with the RGA was AMU 57 for parallel and perpendicular layers, due to the abundance of this mass value in the disintegration process of C32 in the mass spectrometers ionizer. Moreover, the AMU 57 signal does not interfere with other signals coming from residual gases in the vacuum chamber. The desorption energies obtained were ΔEdes = 11,9 kJ/mol for the perpendicular bilayer and ΔEdes = 23 ,5 kJ/mol for the parallel bilayer.

Superstrate sub-cell voltage-matched multijunction solar cells

DOEpatents

Mascarenhas, Angelo; Alberi, Kirstin

2016-03-15

Voltage-matched thin film multijunction solar cell and methods of producing cells having upper CdTe pn junction layers formed on a transparent substrate which in the completed device is operatively positioned in a superstate configuration. The solar cell also includes a lower pn junction formed independently of the CdTe pn junction and an insulating layer between CdTe and lower pn junctions. The voltage-matched thin film multijunction solar cells further include a parallel connection between the CdTe pn junction and lower pn junctions to form a two-terminal photonic device. Methods of fabricating devices from independently produced upper CdTe junction layers and lower junction layers are also disclosed.

Implementation of 5-layer thermal diffusion scheme in weather research and forecasting model with Intel Many Integrated Cores

NASA Astrophysics Data System (ADS)

Huang, Melin; Huang, Bormin; Huang, Allen H.

2014-10-01

For weather forecasting and research, the Weather Research and Forecasting (WRF) model has been developed, consisting of several components such as dynamic solvers and physical simulation modules. WRF includes several Land- Surface Models (LSMs). The LSMs use atmospheric information, the radiative and precipitation forcing from the surface layer scheme, the radiation scheme, and the microphysics/convective scheme all together with the land's state variables and land-surface properties, to provide heat and moisture fluxes over land and sea-ice points. The WRF 5-layer thermal diffusion simulation is an LSM based on the MM5 5-layer soil temperature model with an energy budget that includes radiation, sensible, and latent heat flux. The WRF LSMs are very suitable for massively parallel computation as there are no interactions among horizontal grid points. The features, efficient parallelization and vectorization essentials, of Intel Many Integrated Core (MIC) architecture allow us to optimize this WRF 5-layer thermal diffusion scheme. In this work, we present the results of the computing performance on this scheme with Intel MIC architecture. Our results show that the MIC-based optimization improved the performance of the first version of multi-threaded code on Xeon Phi 5110P by a factor of 2.1x. Accordingly, the same CPU-based optimizations improved the performance on Intel Xeon E5- 2603 by a factor of 1.6x as compared to the first version of multi-threaded code.

Magnetospheric Multiscale Observations of Large-Amplitude Parallel, Electrostatic Waves Associated with Magnetic Reconnection at the Magnetopause

NASA Technical Reports Server (NTRS)

Ergun, R. E.; Holmes, J. C.; Goodrich, K. A.; Wilder, F. D.; Stawarz, J. E.; Eriksson, S.; Newman, D. L.; Schwartz, S. J.; Goldman, M. V.; Sturner, A. P.;

Charon Toolkit for Parallel, Implicit Structured-Grid Computations: Functional Design

NASA Technical Reports Server (NTRS)

VanderWijngaart, Rob F.; Kutler, Paul (Technical Monitor)

1997-01-01

In a previous report the design concepts of Charon were presented. Charon is a toolkit that aids engineers in developing scientific programs for structured-grid applications to be run on MIMD parallel computers. It constitutes an augmentation of the general-purpose MPI-based message-passing layer, and provides the user with a hierarchy of tools for rapid prototyping and validation of parallel programs, and subsequent piecemeal performance tuning. Here we describe the implementation of the domain decomposition tools used for creating data distributions across sets of processors. We also present the hierarchy of parallelization tools that allows smooth translation of legacy code (or a serial design) into a parallel program. Along with the actual tool descriptions, we will present the considerations that led to the particular design choices. Many of these are motivated by the requirement that Charon must be useful within the traditional computational environments of Fortran 77 and C. Only the Fortran 77 syntax will be presented in this report.

Bistatic scattering from a three-dimensional object above a two-dimensional randomly rough surface modeled with the parallel FDTD approach.

PubMed

Guo, L-X; Li, J; Zeng, H

2009-11-01

We present an investigation of the electromagnetic scattering from a three-dimensional (3-D) object above a two-dimensional (2-D) randomly rough surface. A Message Passing Interface-based parallel finite-difference time-domain (FDTD) approach is used, and the uniaxial perfectly matched layer (UPML) medium is adopted for truncation of the FDTD lattices, in which the finite-difference equations can be used for the total computation domain by properly choosing the uniaxial parameters. This makes the parallel FDTD algorithm easier to implement. The parallel performance with different number of processors is illustrated for one rough surface realization and shows that the computation time of our parallel FDTD algorithm is dramatically reduced relative to a single-processor implementation. Finally, the composite scattering coefficients versus scattered and azimuthal angle are presented and analyzed for different conditions, including the surface roughness, the dielectric constants, the polarization, and the size of the 3-D object.

Magnetic intermittency of solar wind turbulence in the dissipation range

NASA Astrophysics Data System (ADS)

Pei, Zhongtian; He, Jiansen; Tu, Chuanyi; Marsch, Eckart; Wang, Linghua

2016-04-01

The feature, nature, and fate of intermittency in the dissipation range are an interesting topic in the solar wind turbulence. We calculate the distribution of flatness for the magnetic field fluctuations as a functionof angle and scale. The flatness distribution shows a "butterfly" pattern, with two wings located at angles parallel/anti-parallel to local mean magnetic field direction and main body located at angles perpendicular to local B0. This "butterfly" pattern illustrates that the flatness profile in (anti-) parallel direction approaches to the maximum value at larger scale and drops faster than that in perpendicular direction. The contours for probability distribution functions at different scales illustrate a "vase" pattern, more clear in parallel direction, which confirms the scale-variation of flatness and indicates the intermittency generation and dissipation. The angular distribution of structure function in the dissipation range shows an anisotropic pattern. The quasi-mono-fractal scaling of structure function in the dissipation range is also illustrated and investigated with the mathematical model for inhomogeneous cascading (extended p-model). Different from the inertial range, the extended p-model for the dissipation range results in approximate uniform fragmentation measure. However, more complete mathematicaland physical model involving both non-uniform cascading and dissipation is needed. The nature of intermittency may be strong structures or large amplitude fluctuations, which may be tested with magnetic helicity. In one case study, we find the heating effect in terms of entropy for large amplitude fluctuations seems to be more obvious than strong structures.

The Record of Tsunamis and Storms in a Coastal Mangrove Pond, NW Puerto Rico

NASA Astrophysics Data System (ADS)

Jaffe, B. E.; Buckley, M. L.; Watt, S. G.; Moya, J. C.; Richmond, B. M.; Gelfenbaum, G. R.; La Selle, S.

2017-12-01

The written record of tsunamis in the Caribbean extends back over 500 years, yet, is incomplete. In particular, it is not known whether great earthquakes or submarine landslides near the Puerto Rico Trench have generated large tsunamis that impact the north coast of Puerto Rico. We cored a coastal mangrove pond in NW Puerto Rico to search for tsunami deposits. The pond extends from 150 to 350 m from the shoreline, and is 0.5 m above sea level. The area between the pond and the ocean presently has a high of 3 m above sea level, but had dunes up to 10 m high before they were mined for sand beginning in the 1960s. Pond sediments are predominately mud or mangrove peat and contain prominent sand layers. At the sediment surface, a tabular sandy overwash deposit up to 40 cm thick extends inland approximately 30 m from the pond's seaward edge and abruptly ends. This sand layer contains no evidence of vertical grading and was likely formed by one or more recent hurricanes, which with the removal of coastal dunes in the 1960s are able to flood the pond. In contrast, underlying the overwash deposit and mangrove peat at a depth of approximately 60 cm is a thin (1 - 7 cm thick) sand layer extending to the landward limit of the pond. This layer has features of a tsunami deposit, including suspension grading, which is a specific type of normal grading where the entire grain-size distribution shifts to finer sizes upward that is created when sediment settles out of suspension as a high-speed flow wanes, an erosive basal contact, and an organic cap. In addition, couplets or triplets of sand inter-layered with mud are present within the thin sandy layer at some locations. Alternation of sand and mud layers at this scale is a signature of series of tsunami waves. Radiocarbon dates from organic material above and below the thin sand layer constrain deposition as occurring sometime from 1446 to 1919 AD. We present the features of the coastal mangrove pond deposits and evaluate whether these deposits could be correlated with an extreme wave overwash that left a deposit on Anegada, BVI, sometime between 1200 and 1480 AD, which would support a great Puerto Rico Trench earthquake and tsunami about 600 years ago.

ARSENAL: A Cross Layer Architecture for Secure Resilient Tactical Mobile AdHoc Networks

DTIC Science & Technology

2016-01-21

stations separated by 0.5 to 1 km can be coherently measured to a single mobile subscriber using LTE signaling. These are the first measurements of...undertake three parallel but inter-coupled tasks geared towards a) performing measurements via real deployments and enhancing our understanding of layer...dependencies and vulnerabilities in mobile ad hoc networks; these measurements will be on existing testbeds at The views, opinions and/or findings

ARSENAL: A Cross Layer Architecture for SecureResilient Tactical Mobile AdHoc Networks

DTIC Science & Technology

2016-01-21

stations separated by 0.5 to 1 km can be coherently measured to a single mobile subscriber using LTE signaling. These are the first measurements of...undertake three parallel but inter-coupled tasks geared towards a) performing measurements via real deployments and enhancing our understanding of layer...dependencies and vulnerabilities in mobile ad hoc networks; these measurements will be on existing testbeds at The views, opinions and/or findings

Features of sound propagation through and stability of a finite shear layer

NASA Technical Reports Server (NTRS)

Koutsoyannis, S. P.

1976-01-01

The plane wave propagation, the stability and the rectangular duct mode problems of a compressible inviscid linearly sheared parallel, but otherwise homogeneous flow, are shown to be governed by Whittaker's equation. The exact solutions for the perturbation quantities are essentially Whittaker M-functions. A number of known results are obtained as limiting cases of exact solutions. For the compressible finite thickness shear layer it is shown that no resonances and no critical angles exist for all Mach numbers, frequencies and shear layer velocity profile slopes except in the singular case of the vortex sheet.

Bragg scattering of electromagnetic waves by microwave-produced plasma layers

NASA Technical Reports Server (NTRS)

Kuo, S. P.; Zhang, Y. S.

1990-01-01

A set of parallel plasma layers is generated by two intersecting microwave pulses in a chamber containing dry air at a pressure comparable to the upper atmosphere. The dependencies of breakdown conditions on the pressure and pulse length are examined. The results are shown to be consistent with the appearance of tail erosion of the microwave pulse caused by air breakdown. A Bragg scattering experiment, using the plasma layers as a Bragg reflector, is then performed. Both time domain and frequency domain measurements of wave scattering are conducted. The experimental results are found to agree very well with the theory.

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

Kahlenberg, Volker; Konzett, Juergen; Kaindl, Reinhard

High-pressure synthesis experiments in the system Na{sub 2}O-Y{sub 2}O{sub 3}-SiO{sub 2} revealed the existence of a previously unknown polymorph of NaYSi{sub 2}O{sub 6} or Na{sub 3}Y{sub 3}[Si{sub 3}O{sub 9}]{sub 2} which was quenched from 3.0 GPa and 1000 deg. C. Structural investigations on this modification have been performed using single-crystal X-ray diffraction data collected at ambient conditions. Furthermore, unpolarized micro-Raman spectra have been obtained from single-crystal material. The high-P modification of NaYSi{sub 2}O{sub 6} crystallizes in the centrosymmetric space group C2/c with 12 formula units per cell (a=8.2131(9) A, b=10.3983(14) A, c=17.6542(21) A, {beta}=100.804(9){sup o}, V=1481.0(3) A{sup 3}, R(|F|)=0.033 formore » 1142 independent observed reflections) and belongs to the group of cyclo-silicates. Basic building units are isolated three-membered [Si{sub 3}O{sub 9}] rings located in layers parallel to (010). Within a single layer the rings are concentrated in strings parallel to [100]. The sequence of directedness of up (U) or down (D) pointing tetrahedra of a single ring is UUU or DDD, respectively. Stacking of the layers parallel to b results in the formation of a three-dimensional structure in which yttrium and sodium cations are incorporated for charge compensation. In more detail, four non-tetrahedral cation positions can be differentiated which are coordinated by 6 and 8 oxygen ligands. Refinements of the site occupancies did not reveal any indication for mixed Na-Y populations on these positions. Finally, several geometrical parameters of rings occurring in cyclo-trisilicate structures have been compiled and are discussed. - Graphical abstract: Projection of the whole structure of high-P NaYSi{sub 2}O{sub 6} parallel to [100].« less

Extension and Validation of a Hybrid Particle-Finite Element Method for Hypervelocity Impact Simulation. Chapter 2

NASA Technical Reports Server (NTRS)

Fahrenthold, Eric P.; Shivarama, Ravishankar

2004-01-01

The hybrid particle-finite element method of Fahrenthold and Horban, developed for the simulation of hypervelocity impact problems, has been extended to include new formulations of the particle-element kinematics, additional constitutive models, and an improved numerical implementation. The extended formulation has been validated in three dimensional simulations of published impact experiments. The test cases demonstrate good agreement with experiment, good parallel speedup, and numerical convergence of the simulation results.

Extending HPF for advanced data parallel applications

NASA Technical Reports Server (NTRS)

Chapman, Barbara; Mehrotra, Piyush; Zima, Hans

1994-01-01

The stated goal of High Performance Fortran (HPF) was to 'address the problems of writing data parallel programs where the distribution of data affects performance'. After examining the current version of the language we are led to the conclusion that HPF has not fully achieved this goal. While the basic distribution functions offered by the language - regular block, cyclic, and block cyclic distributions - can support regular numerical algorithms, advanced applications such as particle-in-cell codes or unstructured mesh solvers cannot be expressed adequately. We believe that this is a major weakness of HPF, significantly reducing its chances of becoming accepted in the numeric community. The paper discusses the data distribution and alignment issues in detail, points out some flaws in the basic language, and outlines possible future paths of development. Furthermore, we briefly deal with the issue of task parallelism and its integration with the data parallel paradigm of HPF.

Parallel Implicit Runge-Kutta Methods Applied to Coupled Orbit/Attitude Propagation

NASA Astrophysics Data System (ADS)

Hatten, Noble; Russell, Ryan P.

2017-12-01

A variable-step Gauss-Legendre implicit Runge-Kutta (GLIRK) propagator is applied to coupled orbit/attitude propagation. Concepts previously shown to improve efficiency in 3DOF propagation are modified and extended to the 6DOF problem, including the use of variable-fidelity dynamics models. The impact of computing the stage dynamics of a single step in parallel is examined using up to 23 threads and 22 associated GLIRK stages; one thread is reserved for an extra dynamics function evaluation used in the estimation of the local truncation error. Efficiency is found to peak for typical examples when using approximately 8 to 12 stages for both serial and parallel implementations. Accuracy and efficiency compare favorably to explicit Runge-Kutta and linear-multistep solvers for representative scenarios. However, linear-multistep methods are found to be more efficient for some applications, particularly in a serial computing environment, or when parallelism can be applied across multiple trajectories.

Extensions to the Parallel Real-Time Artificial Intelligence System (PRAIS) for fault-tolerant heterogeneous cycle-stealing reasoning

NASA Technical Reports Server (NTRS)

Goldstein, David

1991-01-01

Extensions to an architecture for real-time, distributed (parallel) knowledge-based systems called the Parallel Real-time Artificial Intelligence System (PRAIS) are discussed. PRAIS strives for transparently parallelizing production (rule-based) systems, even under real-time constraints. PRAIS accomplished these goals (presented at the first annual C Language Integrated Production System (CLIPS) conference) by incorporating a dynamic task scheduler, operating system extensions for fact handling, and message-passing among multiple copies of CLIPS executing on a virtual blackboard. This distributed knowledge-based system tool uses the portability of CLIPS and common message-passing protocols to operate over a heterogeneous network of processors. Results using the original PRAIS architecture over a network of Sun 3's, Sun 4's and VAX's are presented. Mechanisms using the producer-consumer model to extend the architecture for fault-tolerance and distributed truth maintenance initiation are also discussed.

Electrodynamic properties of a hypercrystal with ferrite and semiconductor layers in an external magnetic field

NASA Astrophysics Data System (ADS)

Fedorin, Illia V.

2018-01-01

Electrodynamic properties of a photonic hypercrystal formed by periodically alternating two types of anisotropic metamaterials are studied. The first metamaterial consists of ferrite and dielectric layers, while the second metamaterial consists of semiconductor and dielectric layers. The system is assumed to be placed in an external magnetic field, which applied parallel to the boundaries of the layers. An effective medium theory which is suitable for calculation of properties of long-wavelength electromagnetic modes is applied in order to derive averaged expressions for effective constitutive parameters. It has been shown that providing a conscious choice of the constitutive parameters and material fractions of magnetic, semiconductor, and dielectric layers, the system under study shows hypercrystal properties for both TE and TM waves in the different frequency ranges.

Apparatus and Process for Controlled Nanomanufacturing Using Catalyst Retaining Structures

NASA Technical Reports Server (NTRS)

Nguyen, Cattien (Inventor)

2013-01-01

An apparatus and method for the controlled fabrication of nanostructures using catalyst retaining structures is disclosed. The apparatus includes one or more modified force microscopes having a nanotube attached to the tip portion of the microscopes. An electric current is passed from the nanotube to a catalyst layer of a substrate, thereby causing a localized chemical reaction to occur in a resist layer adjacent the catalyst layer. The region of the resist layer where the chemical reaction occurred is etched, thereby exposing a catalyst particle or particles in the catalyst layer surrounded by a wall of unetched resist material. Subsequent chemical vapor deposition causes growth of a nanostructure to occur upward through the wall of unetched resist material having controlled characteristics of height and diameter and, for parallel systems, number density.

Charge dissipative dielectric for cryogenic devices

NASA Technical Reports Server (NTRS)

Cantor, Robin Harold (Inventor); Hall, John Addison (Inventor)

2007-01-01

A Superconducting Quantum Interference Device (SQUID) is disclosed comprising a pair of resistively shunted Josephson junctions connected in parallel within a superconducting loop and biased by an external direct current (dc) source. The SQUID comprises a semiconductor substrate and at least one superconducting layer. The metal layer(s) are separated by or covered with a semiconductor material layer having the properties of a conductor at room temperature and the properties of an insulator at operating temperatures (generally less than 100 Kelvins). The properties of the semiconductor material layer greatly reduces the risk of electrostatic discharge that can damage the device during normal handling of the device at room temperature, while still providing the insulating properties desired to allow normal functioning of the device at its operating temperature. A method of manufacturing the SQUID device is also disclosed.

Thigh muscle and subcutaneous tissue thickness measured using ultrasound imaging in older females living in extended care: a preliminary study.

PubMed

Welch, Daniella; Ndanyo, Laetitia Sungu; Brown, Simon; Agyapong-Badu, Sandra; Warner, Martin; Stokes, Maria; Samuel, Dinesh

2018-05-01

Thigh tissue thickness has not been examined in older females living in extended care in UK as an indicator of musculoskeletal health. This study examined the feasibility of using ultrasound imaging to measure the thickness of superficial (fat) and deep layers (muscle) of the thigh in older females living in extended care. In ten older females in extended care (aged 80-98 years, mean 88 ± 6.8; body mass: 56.5 ± 12.6 kg) images of the anterior thigh (dominant) were taken in supine using B-mode ultrasound imaging. Superficial and deep layers were measured and percentage thickness was calculated. Independent t tests compared data from those in extended care to ten sedentary females living independently (aged 80-90 years, mean 84 ± 3.6; body mass: 61.6 ± 10.0 kg). Thickness of the superficial layers was not significantly different between the two groups (CI -0.017 to 0.815, p = 0.059). However, those living in extended care had greater (p < 0.001) muscle thickness (mean 2.75 ± 0.48 cm) than those living independently (mean 1.83 ± 0.3 cm), which was similarly significant when normalised for body mass (extended care 0.51 ± 0.16; independent living 0.30 ± 0.06). These novel findings showed it is feasible to use ultrasound to measure muscles in older females in extended care and that muscle thickness was larger than in those living independently. The reason for the difference seen between groups would need to be confirmed by a larger study that also examined factors related to risk of sarcopenia and frailty, such as nutrition and physical activity levels.

Pronounced zonation of seismic anisotropy in the Western Hellenic subduction zone and its geodynamic significance

NASA Astrophysics Data System (ADS)

Olive, Jean-Arthur; Pearce, Frederick; Rondenay, Stéphane; Behn, Mark D.

2014-04-01

Many subduction zones exhibit significant retrograde motion of their arc and trench. The observation of fast shear-wave velocities parallel to the trench in such settings has been inferred to represent trench-parallel mantle flow beneath a retreating slab. Here, we investigate this process by measuring seismic anisotropy in the shallow Aegean mantle. We carry out shear-wave splitting analysis on a dense array of seismometers across the Western Hellenic Subduction Zone, and find a pronounced zonation of anisotropy at the scale of the subduction zone. Fast SKS splitting directions subparallel to the trench-retreat direction dominate the region nearest to the trench. Fast splitting directions abruptly transition to trench-parallel above the corner of the mantle wedge, and rotate back to trench-normal over the back-arc. We argue that the trench-normal anisotropy near the trench is explained by entrainment of an asthenospheric layer beneath the shallow-dipping portion of the slab. Toward the volcanic arc this signature is overprinted by trench-parallel anisotropy in the mantle wedge, likely caused by a layer of strained serpentine immediately above the slab. Arcward steepening of the slab and horizontal divergence of mantle flow due to rollback may generate an additional component of sub-slab trench-parallel anisotropy in this region. Poloidal flow above the retreating slab is likely the dominant source of back-arc trench-normal anisotropy. We hypothesize that trench-normal anisotropy associated with significant entrainment of the asthenospheric mantle near the trench may be widespread but only observable at shallow-dipping subduction zones where stations nearest the trench do not overlie the mantle wedge.

Structural disorder and elementary magnetic properties of triangular lattice ErMgGaO 4 single crystals

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

Cevallos, F. Alex; Stolze, Karoline; Cava, Robert J.

The single crystal growth, structure, and basic magnetic properties of ErMgGaO 4 are reported. The structure consists of triangular layers of magnetic ErO 6 octahedra separated by a double layer of randomly occupied non-magnetic (Ga,Mg)O 5 bipyramids. The Er atoms are positionally disordered. Magnetic measurements parallel and perpendicular to the c axis of a single crystal reveal dominantly antiferromagnetic interactions, with a small degree of magnetic anisotropy. A weighted average of the directional data suggests an antiferromagnetic Curie Weiss temperature of approximately -30 K. Below 10 K the temperature dependences of the inverse susceptibilities in the in-plane and perpendicular-to planemore » directions are parallel, indicative of an isotropic magnetic moment at low temperatures. In conclusion, no sign of magnetic ordering is observed above 1.8 K, suggesting that ErMgGaO 4 is a geometrically frustrated magnet.« less

High extraction efficiency ultraviolet light-emitting diode

DOEpatents

Wierer, Jonathan; Montano, Ines; Allerman, Andrew A.

2015-11-24

Ultraviolet light-emitting diodes with tailored AlGaN quantum wells can achieve high extraction efficiency. For efficient bottom light extraction, parallel polarized light is preferred, because it propagates predominately perpendicular to the QW plane and into the typical and more efficient light escape cones. This is favored over perpendicular polarized light that propagates along the QW plane which requires multiple, lossy bounces before extraction. The thickness and carrier density of AlGaN QW layers have a strong influence on the valence subband structure, and the resulting optical polarization and light extraction of ultraviolet light-emitting diodes. At Al>0.3, thinner QW layers (<2.5 nm are preferred) result in light preferentially polarized parallel to the QW plane. Also, active regions consisting of six or more QWs, to reduce carrier density, and with thin barriers, to efficiently inject carriers in all the QWs, are preferred.

A Model of In vitro Plasticity at the Parallel Fiber—Molecular Layer Interneuron Synapses

PubMed Central

Lennon, William; Yamazaki, Tadashi; Hecht-Nielsen, Robert

2015-01-01

Theoretical and computational models of the cerebellum typically focus on the role of parallel fiber (PF)—Purkinje cell (PKJ) synapses for learned behavior, but few emphasize the role of the molecular layer interneurons (MLIs)—the stellate and basket cells. A number of recent experimental results suggest the role of MLIs is more important than previous models put forth. We investigate learning at PF—MLI synapses and propose a mathematical model to describe plasticity at this synapse. We perform computer simulations with this form of learning using a spiking neuron model of the MLI and show that it reproduces six in vitro experimental results in addition to simulating four novel protocols. Further, we show how this plasticity model can predict the results of other experimental protocols that are not simulated. Finally, we hypothesize what the biological mechanisms are for changes in synaptic efficacy that embody the phenomenological model proposed here. PMID:26733856

Bis(1,3-dimethyl-1H-imidazolium) hexa-fluoro-silicate: the second monoclinic polymorph.

PubMed

Tian, Chong; Nie, Wanli; Borzov, Maxim V

2013-01-01

The title compound, 2C5H9N2 (+)·SiF6 (2-), (I), crystallized as a new polymorph, different from the previously reported one (Ia) [Light et al. (2007 ▶) private communication (refcode: NIQFAV). CCDC, Cambridge, England]. The symmetry [space groups P21/n for (I) and C2/c for(Ia)] and crystal packing patterns are markedly different for this pair of polymorphs. In (I), all imidazolium cations in the lattice are nearly parallel to each other, whereas a herringbone arrangement can be found in (Ia). In (I), each SiF6 (2-) dianion forms four short C-H⋯F contacts with adjacent C5H9N2 (+) cations, resulting in the formation of layers parallel to the ac plane. In (Ia), the C-H⋯F contacts are generally longer and result in the formation of layers along the bc plane.

Structural disorder and elementary magnetic properties of triangular lattice ErMgGaO 4 single crystals

DOE PAGES

Cevallos, F. Alex; Stolze, Karoline; Cava, Robert J.

2018-03-23

The single crystal growth, structure, and basic magnetic properties of ErMgGaO 4 are reported. The structure consists of triangular layers of magnetic ErO 6 octahedra separated by a double layer of randomly occupied non-magnetic (Ga,Mg)O 5 bipyramids. The Er atoms are positionally disordered. Magnetic measurements parallel and perpendicular to the c axis of a single crystal reveal dominantly antiferromagnetic interactions, with a small degree of magnetic anisotropy. A weighted average of the directional data suggests an antiferromagnetic Curie Weiss temperature of approximately -30 K. Below 10 K the temperature dependences of the inverse susceptibilities in the in-plane and perpendicular-to planemore » directions are parallel, indicative of an isotropic magnetic moment at low temperatures. In conclusion, no sign of magnetic ordering is observed above 1.8 K, suggesting that ErMgGaO 4 is a geometrically frustrated magnet.« less

Elastic Properties of 3D-Printed Rock Models: Dry and Saturated Cracks

NASA Astrophysics Data System (ADS)

Huang, L.; Stewart, R.; Dyaur, N.

2014-12-01

Many regions of subsurface interest are, or will be, fractured. In addition, these zones many be subject to varying saturations and stresses. New 3D printing techniques using different materials and structures, provide opportunities to understand porous or fractured materials and fluid effects on their elastic properties. We use a 3D printer (Stratasys Dimension SST 768) to print two rock models: a solid octahedral prism and a porous cube with thousands of penny-shaped cracks. The printing material is ABS thermal plastic with a density of 1.04 g/cm3. After printing, we measure the elastic properties of the models, both dry and 100% saturated with water. Both models exhibit VTI (Vertical Transverse Isotropic) symmetry due to laying (about 0.25 mm thick) of the printing process. The prism has a density of 0.96 g/cm3 before saturation and 1.00 g/cm3 after saturation. Its effective porosity is calculated to be 4 %. We use ultrasonic transducers (500 kHz) to measure both P- and shear-wave velocities, and the raw material has a P-wave velocity of 1.89 km/s and a shear-wave velocity of 0.91 km/s. P-wave velocity in the un-saturated prism increases from 1.81 km/s to 1.84 km/s after saturation in the direction parallel to layering and from 1.73 km/s to 1.81 km/s in the direction perpendicular to layering. The fast shear-wave velocity decreases from 0.88 km/s to 0.87 km/s and the slow shear-wave velocity decreases from 0.82 km/s to 0.81 km/s. The cube, printed with penny-shaped cracks, gives a density of 0.79 g/cm3 and a porosity of 24 %. We measure its P-wave velocity as 1.78 km/s and 1.68 km/s in the direction parallel and perpendicular to the layering, respectively. Its fast shear-wave velocity is 0.88 km/s and slow shear-wave velocity is 0.70 km/s. The penny-shaped cracks have significant influence on the elastic properties of the 3D-printed rock models. To better understand and explain the fluid effects on the elastic properties of the models, we apply the extended anisotropic Gassmann's equations to predict the effects of saturation changes. We find that the predictions match observations from the experimental data within 1 % difference.

Extendable pipe crawler

DOEpatents

Hapstack, Mark

1991-01-01

A pipe crawler having a front leg assembly and a back leg assembly connected together by two air cylinders, each leg assembly having four extendable legs and a pair of actuators for sliding the extendable legs radially outward to increase the range of the legs when the pipe crawler enters a section of a pipe having a larger diameter. The crawler crawls by "inchworm"-like motion, the front leg assembly and back leg assembly alternately engaging and disengaging the wall of the pipe to hold the pipe crawler as the air cylinders alternately advance the front leg assembly and bring up the rear leg assembly. The pair of actuators of each leg assembly are parallel, adjacent and opposing acting so that each slides two adjacent extendable legs radially outward.

Comparisons of predicted steady-state levels in rooms with extended- and local-reaction bounding surfaces

NASA Astrophysics Data System (ADS)

Hodgson, Murray; Wareing, Andrew

2008-01-01

A combined beam-tracing and transfer-matrix model for predicting steady-state sound-pressure levels in rooms with multilayer bounding surfaces was used to compare the effect of extended- and local-reaction surfaces, and the accuracy of the local-reaction approximation. Three rooms—an office, a corridor and a workshop—with one or more multilayer test surfaces were considered. The test surfaces were a single-glass panel, a double-drywall panel, a carpeted floor, a suspended-acoustical ceiling, a double-steel panel, and glass fibre on a hard backing. Each test surface was modeled as of extended or of local reaction. Sound-pressure levels were predicted and compared to determine the significance of the surface-reaction assumption. The main conclusions were that the difference between modeling a room surface as of extended or of local reaction is not significant when the surface is a single plate or a single layer of material (solid or porous) with a hard backing. The difference is significant when the surface consists of multilayers of solid or porous material and includes a layer of fluid with a large thickness relative to the other layers. The results are partially explained by considering the surface-reflection coefficients at the first-reflection angles.

Membranes having aligned 1-D nanoparticles in a matrix layer for improved fluid separation

DOEpatents

Revanur, Ravindra; Lulevich, Valentin; Roh, Il Juhn; Klare, Jennifer E.; Kim, Sangil; Noy, Aleksandr; Bakajin, Olgica

2015-12-22

Membranes for fluid separation are disclosed. These membranes have a matrix layer sandwiched between an active layer and a porous support layer. The matrix layer includes 1-D nanoparticles that are vertically aligned in a porous polymer matrix, and which substantially extend through the matrix layer. The active layer provides species-specific transport, while the support layer provides mechanical support. A matrix layer of this type has favorable surface morphology for forming the active layer. Furthermore, the pores that form in the matrix layer tend to be smaller and more evenly distributed as a result of the presence of aligned 1-D nanoparticles. Improved performance of separation membranes of this type is attributed to these effects.