Slip-stacking Dynamics for High-Power Proton Beams at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Eldred, Jeffrey Scott [Indiana Univ., Bloomington, IN (United States)

2015-12-01

Slip-stacking is a particle accelerator configuration used to store two particle beams with different momenta in the same ring. The two beams are longitudinally focused by two radiofrequency (RF) cavities with a small frequency difference between them. Each beam is synchronized to one RF cavity and perturbed by the other RF cavity. Fermilab uses slip-stacking in the Recycler so as to double the power of the 120 GeV proton beam in the Main Injector. This dissertation investigates the dynamics of slip-stacking beams analytically, numerically and experimentally. In the analytic analysis, I find the general trajectory of stable slip-stacking particles and identify the slip-stacking parametric resonances. In the numerical analysis, I characterize the stable phase-space area and model the particle losses. In particular, I evaluate the impact of upgrading the Fermilab Booster cycle-rate from 15 Hz to 20 Hz as part of the Proton Improvement Plan II (PIP-II). The experimental analysis is used to verify my approach to simulating slip-stacking loss. I design a study for measuring losses from the longitudinal single-particle dynamics of slip-stacking as a function of RF cavity voltage and RF frequency separation. I further propose the installation of a harmonic RF cavity and study the dynamics of this novel slip-stacking configuration. I show the harmonic RF cavity cancels out parametric resonances in slip-stacking, reduces emittance growth during slip-stacking, and dramatically enhances the stable phase-space area. The harmonic cavity is expected to reduce slip-stacking losses to far exceed PIP-II requirements. These results raise the possibility of extending slip-stacking beyond the PIP-II era.

Influence of the stacking sequence of layers on the mechanical behavior of polymeric composite cylinders; Influencia da configuracao de bobinagem no comportamento mecanico de cilindros de composito polimerico

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Osni de

2006-07-01

This work evaluated experimentally the influence of the stacking sequence of layers symmetrical and asymmetrical on the mechanical behavior of polymeric composite cylinders. For so much, two open-ended cylinders groups were manufactured by filament winding process, which had different stacking sequence related to the laminate midplane, characterizing symmetrical and asymmetrical laminates. The composite cylinders were made with epoxy matrix and carbon fiber as reinforcement. For evaluation of the mechanical strength, the cylinders were tested hydrostatically, which consisted of internal pressurization in a hydrostatic device through the utilization of a fluid until the cylinders burst. Additionally, were compared the strains and failure modes between the cylinders groups. The utilization of a finite element program allowed to conclude that this tool, very used in design, does not get to identify tensions in the fiber direction in each composite layer, as well as interlaminar shear stress, that appears in the cylinders with asymmetrical stacking sequence. The tests results showed that the stacking sequence had influence in the mechanical behavior of the composite cylinders, favoring the symmetrical construction. (author)

Dynamical stability of slip-stacking particles

Energy Technology Data Exchange (ETDEWEB)

Eldred, Jeffrey; Zwaska, Robert

2014-09-01

We study the stability of particles in slip-stacking configuration, used to nearly double proton beam intensity at Fermilab. We introduce universal area factors to calculate the available phase space area for any set of beam parameters without individual simulation. We find perturbative solutions for stable particle trajectories. We establish Booster beam quality requirements to achieve 97% slip-stacking efficiency. We show that slip-stacking dynamics directly correspond to the driven pendulum and to the system of two standing-wave traps moving with respect to each other.

Optimum stacking sequence design of laminated composite circular plates with curvilinear fibres by a layer-wise optimization method

Science.gov (United States)

Guenanou, A.; Houmat, A.

2018-05-01

The optimum stacking sequence design for the maximum fundamental frequency of symmetrically laminated composite circular plates with curvilinear fibres is investigated for the first time using a layer-wise optimization method. The design variables are two fibre orientation angles per layer. The fibre paths are constructed using the method of shifted paths. The first-order shear deformation plate theory and a curved square p-element are used to calculate the objective function. The blending function method is used to model accurately the geometry of the circular plate. The equations of motion are derived using Lagrange's method. The numerical results are validated by means of a convergence test and comparison with published values for symmetrically laminated composite circular plates with rectilinear fibres. The material parameters, boundary conditions, number of layers and thickness are shown to influence the optimum solutions to different extents. The results should serve as a benchmark for optimum stacking sequences of symmetrically laminated composite circular plates with curvilinear fibres.

Crystallite size effects in stacking faulted nickel hydroxide and its electrochemical behaviour

International Nuclear Information System (INIS)

Ramesh, T.N.

2009-01-01

β-Nickel hydroxide comprises a long range periodic arrangement of atoms with a stacking sequence of AC AC AC-having an ideal composition Ni(OH) 2 . Variation in the preparative conditions can lead to the changes in the stacking sequence (AC AC BA CB AC AC or AC AC AB AC AC). This type of variation in stacking sequence can result in the formation of stacking fault in nickel hydroxide. The stability of the stacking fault depends on the free energy content of the sample. Stacking faults in nickel hydroxide is essential for better electrochemical activity. Also there are reports correlating particle size to the better electrochemical activity. Here we present the effect of crystallite size on the stacking faulted nickel hydroxide samples. The electrochemical performance of stacking faulted nickel hydroxide with small crystallite size exchanges 0.8e/Ni, while the samples with larger crystallite size exchange 0.4e/Ni. Hence a right combination of crystallite size and stacking fault content has to be controlled for good electrochemical activity of nickel hydroxide

A Mid-Holocene Relative Sea-Level Stack, New Jersey, USA

Science.gov (United States)

Horton, B.; Walker, J. S.; Kemp, A.; Shaw, T. J.; Kopp, R. E.

2017-12-01

Most high resolution (decimeter- and decadal-scale) relative sea-level (RSL) records using salt-marsh microfossils as a proxy only extend through the Common Era, limiting our understanding of driving mechanisms of RSL change and how sea-level is influenced by changing climate. Records beyond the Common Era are limited by the depth of continuous sequences of salt-marsh peat suitable for high resolution reconstructions, as well as contamination by local processes such as sediment compaction. In contrast, sequences of basal peats have produced compaction-free RSL records through the Holocene, but at a low resolution (meter- and centennial-scale). We devise a new Multi-Proxy Presence/Absence Method (MP2AM) to develop a mid-Holocene RSL stack. We stack a series of 1 m basal peat cores that overlap along a uniform elevational gradient above an incompressible basal sand. We analyzed three sea-level indicators from 14 cores: foraminifera, testate amoebae, and stable carbon isotope geochemistry. To reconstruct RSL, this multi-proxy approach uses the timesaving presence/absence of forams and testates to determine the elevation of the highest occurrence of forams and the lowest occurrence of testates in each basal core. We use stable carbon isotope geochemistry to determine the C3/C4 vegetation boundary in each core. We develop age-depth models for each core using a series of radiocarbon dates. The RSL records from each 1 m basal core are combined to create a stack or, in effect, one long core of salt-marsh material. This method removes the issue of compaction to create a continuous RSL record to address temporal changes and periods of climate and sea-level variability. We reconstruct a southern NJ mid-Holocene RSL record from Edwin B. Forsythe National Wildlife Refuge, where Kemp et al. (2013) completed a 2500 yr RSL record using a foraminifera-based transfer function approach. Preliminary radiocarbon dates suggest the basal sequence is at least 4246-4408 cal yrs BP

Stacking non-BPS D-branes

International Nuclear Information System (INIS)

Alberghi, Gian Luigi; Caceres, Elena; Goldstein, Kevin; Lowe, David A. . lowe@het.brown.edu

2001-08-01

We present a candidate supergravity solution for a stacked configuration of stable non-BPS D-branes in Type II string theory compactified on T 4 /Z 2 . This gives a supergravity description of nonabelian tachyon condensation on the brane woldvolume. (author)

Influence of stacking sequence on scattering characteristics of the fundamental anti-symmetric Lamb wave at through holes in composite laminates.

Science.gov (United States)

Veidt, Martin; Ng, Ching-Tai

2011-03-01

This paper investigates the scattering characteristics of the fundamental anti-symmetric (A(0)) Lamb wave at through holes in composite laminates. Three-dimensional (3D) finite element (FE) simulations and experimental measurements are used to study the physical phenomenon. Unidirectional, bidirectional, and quasi-isotropic composite laminates are considered in the study. The influence of different hole diameter to wavelength aspect ratios and different stacking sequences on wave scattering characteristics are investigated. The results show that amplitudes and directivity distribution of the scattered Lamb wave depend on these parameters. In the case of quasi-isotropic composite laminates, the scattering directivity patterns are dominated by the fiber orientation of the outer layers and are quite different for composite laminates with the same number of laminae but different stacking sequence. The study provides improved physical insight into the scattering phenomena at through holes in composite laminates, which is essential to develop, validate, and optimize guided wave damage detection and characterization techniques. © 2011 Acoustical Society of America

Lower Cretaceous paleo-Vertisols and sedimentary interrelationships in stacked alluvial sequences, Utah, USA

Science.gov (United States)

Joeckel, R. M.; Ludvigson, G. A.; Kirkland, J. I.

2017-11-01

The Yellow Cat Member of the Cedar Mountain Formation in Poison Strip, Utah, USA, consists of stacked, erosionally bounded alluvial sequences dominated by massive mudstones (lithofacies Fm) with paleo-Vertisols. Sediment bodies within these sequences grade vertically and laterally into each other at pedogenic boundaries, across which color, texture, and structures (sedimentary vs. pedogenic) change. Slickensides, unfilled (sealed) cracks, carbonate-filled cracks, and deeper cracks filled with sandstone; the latter features suggest thorough desiccation during aridification. Thin sandstones (Sms) in some sequences, typically as well as laminated to massive mudstones (Flm) with which they are interbedded in some cases, are interpreted as avulsion deposits. The termini of many beds of these lithofacies curve upward, parallel to nearby pedogenic slickensides, as the features we call ;turnups.; Turnups are overlain or surrounded by paleosols, but strata sheltered underneath beds with turnups retain primary sedimentary fabrics. Turnups were produced by movement along slickensides during pedogenesis, by differential compaction alongside pre-existing gilgai microhighs, or by a combination of both. Palustrine carbonates (lithofacies C) appear only in the highest or next-highest alluvial sequences, along with a deep paleo-Vertisol that exhibits partially preserved microrelief at the base of the overlying Poison Strip Member. The attributes of the Yellow Cat Member suggest comparatively low accommodation, slow accumulation, long hiatuses in clastic sedimentation, and substantial time intervals of subaerial exposure and pedogenesis; it appears to be distinct among the members of the Cedar Mountain Formation in these respects.

Stacking change in MoS2 bilayers induced by interstitial Mo impurities.

Science.gov (United States)

Cortés, Natalia; Rosales, Luis; Orellana, Pedro A; Ayuela, Andrés; González, Jhon W

2018-02-01

We use a theoretical approach to reveal the electronic and structural properties of molybdenum impurities between MoS 2 bilayers. We find that interstitial Mo impurities are able to reverse the well-known stability order of the pristine bilayer, because the most stable form of stacking changes from AA' (undoped) into AB' (doped). The occurrence of Mo impurities in different positions shows their split electronic levels in the energy gap, following octahedral and tetrahedral crystal fields. The energy stability is related to the accommodation of Mo impurities compacted in hollow sites between layers. Other less stable configurations for Mo dopants have larger interlayer distances and band gaps than those for the most stable stacking. Our findings suggest possible applications such as exciton trapping in layers around impurities, and the control of bilayer stacking by Mo impurities in the growth process.

Electrically Conductive and Protective Coating for Planar SOFC Stacks

Energy Technology Data Exchange (ETDEWEB)

Choi, Jung-Pyung; Stevenson, Jeffry W.

2017-12-04

Ferritic stainless steels are preferred interconnect materials for intermediate temperature SOFCs because of their resistance to oxidation, high formability and low cost. However, their protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Electrically conducting spinel coatings have been developed to prevent cathode poisoning and to maintain an electrically conductive pathway through SOFC stacks. However, this coating is not compatible with the formation of stable, hermetic seals between the interconnect frame component and the ceramic cell. Thus, a new aluminizing process has been developed by PNNL to enable durable sealing, prevent Cr evaporation, and maintain electrical insulation between stack repeat units. Hence, two different types of coating need to have stable operation of SOFC stacks. This paper will focus on the electrically conductive coating process. Moreover, an advanced coating process, compatible with a non-electrically conductive coating will be

Atomic and electronic structure of trilayer graphene/SiC(0001): Evidence of Strong Dependence on Stacking Sequence and charge transfer.

Science.gov (United States)

Pierucci, Debora; Brumme, Thomas; Girard, Jean-Christophe; Calandra, Matteo; Silly, Mathieu G; Sirotti, Fausto; Barbier, Antoine; Mauri, Francesco; Ouerghi, Abdelkarim

2016-09-15

The transport properties of few-layer graphene are the directly result of a peculiar band structure near the Dirac point. Here, for epitaxial graphene grown on SiC, we determine the effect of charge transfer from the SiC substrate on the local density of states (LDOS) of trilayer graphene using scaning tunneling microscopy/spectroscopy and angle resolved photoemission spectroscopy (ARPES). Different spectra are observed and are attributed to the existence of two stable polytypes of trilayer: Bernal (ABA) and rhomboedreal (ABC) staking. Their electronic properties strongly depend on the charge transfer from the substrate. We show that the LDOS of ABC stacking shows an additional peak located above the Dirac point in comparison with the LDOS of ABA stacking. The observed LDOS features, reflecting the underlying symmetry of the two polytypes, were reproduced by explicit calculations within density functional theory (DFT) including the charge transfer from the substrate. These findings demonstrate the pronounced effect of stacking order and charge transfer on the electronic structure of trilayer or few layer graphene. Our approach represents a significant step toward understand the electronic properties of graphene layer under electrical field.

A mathematical model of an automatic assembler to stack fuel pellets

International Nuclear Information System (INIS)

Jarvis, R.G.; Joynes, R.; Bretzlaff, C.I.

1980-11-01

Fuel elements for CANDU reactors are assembled from stacks of cylindrical UO 2 pellets, with close tolerances on lengths and diameters. Present stacking techniques involve extensive manual operations and they can be speeded up and reduced in cost by an automated device. If gamma-active fuel is handled such a device is essential. An automatic fuel pellet assembly process was modelled mathematically. The model indicated a suitable sequence of pellet manipulations to arrive at a stack length that was always within tolerance. This sequence was used as the inital input for the design of mechanical hardware. The mechanical design and the refinement of the mathematical model proceeded simultaneously. Mechanical constraints were allowed for in the model, and its optimized sequence of operations was incorporated in a microcomputer program to control the mechanical hardware. (auth)

Geochronological correlation of the late Precambrian sequences on and around the stable zones of Equatorial Africa

International Nuclear Information System (INIS)

Cahen, L.

1982-01-01

Very few radiometric age determinations have a bearing on the late Precambrian sequences of the stable zones of Equatorial Africa. A geochronological correlation of these sequences must therefore rest upon a compilation of ages from these stable zones and the corresponding mobile zones. About 15 ages of varying precision more or less well tied up with the stratigraphical sequences, together with results of the study of stromatolite assemblages allow a provisional correlation to be made. One conclusion of this correlation is that most mixtites surrounding the Congo basin are in a 950 +- 50 Ma age bracket and are presumably to be correlated. (Auth.)

The retro-GCN4 leucine zipper sequence forms a stable three-dimensional structure

Science.gov (United States)

Mittl, Peer R. E.; Deillon, Christine; Sargent, David; Liu, Niankun; Klauser, Stephan; Thomas, Richard M.; Gutte, Bernd; Grütter, Markus G.

2000-01-01

The question of whether a protein whose natural sequence is inverted adopts a stable fold is still under debate. We have determined the 2.1-Å crystal structure of the retro-GCN4 leucine zipper. In contrast to the two-stranded helical coiled-coil GCN4 leucine zipper, the retro-leucine zipper formed a very stable, parallel four-helix bundle, which now lends itself to further structural and functional studies. PMID:10716989

Maturing of SOFC cell and stack production technology and preparation for demonstration of SOFC stacks. Part 2

Energy Technology Data Exchange (ETDEWEB)

2006-07-01

The TOFC/Riso pilot plant production facility for the manufacture of anode-supported cells has been further up-scaled with an automated continuous spraying process and an extra sintering capacity resulting in production capacity exceeding 15,000 standard cells (12x12 cm2) in 2006 with a success rate of about 85% in the cell production. All processing steps such as tape-casting, spraying, screen-printing and atmospheric air sintering in the cell production have been selected on condition that up-scaling and cost effective, flexible, industrial mass production are feasible. The standard cell size is currently being increased to 18x18 cm2, and 150 cells of this size have been produced in 2006 for our further stack development. To improve quality and lower production cost, a new screen printing line is under establishment. TOFC's stack design is an ultra compact multilayer assembly of cells (including contact layers), metallic interconnects, spacer frames and glass seals. The compactness ensures minimized material consumption and low cost. Standard stacks with cross flow configuration contains 75 cells (12x12cm2) delivering about 1.2 kW at optimal operation conditions with pre-reformed NG as fuel. Stable performance has been demonstrated for 500-1000 hours. Significantly improved materials, especially concerning the metallic interconnect and the coatings have been introduced during the last year. Small stacks (5-10 cells) exhibit no detectable stack degradation using our latest cells and stack materials during test periods of 500-1000 hours. Larger stacks (50-75 cells) suffer from mal-distribution of gas and air inside the stacks, gas leakage, gas cross-over, pressure drop, and a certain loss of internal electrical contact during operation cycles. Measures have been taken to find solutions during the following development work. The stack production facilities have been improved and up-scaled. In 2006, 5 standard stacks have been assembled and burned in based on

Wall-crossing between stable and co-stable ADHM data

Science.gov (United States)

Ohkawa, Ryo

2018-06-01

We prove formula between Nekrasov partition functions defined from stable and co-stable ADHM data for the plane following method by Nakajima and Yoshioka (Kyoto J Math 51(2):263-335, 2011) based on the theory of wall-crossing formula developed by Mochizuki (Donaldson type invariants for algebraic surfaces: transition of moduli stacks, Lecture notes in mathematics, vol 1972, Springer, Berlin, 2009). This formula is similar to conjectures by Ito et al. [J High Energy Phys 2013(5):045, 2013, (4.1), (4.2)] for A1 singularity.

Nature of Interlayer Binding and Stacking of sp–sp 2 Hybridized Carbon Layers: A Quantum Monte Carlo Study

International Nuclear Information System (INIS)

Shin, Hyeondeok; Lee, Hoonkyung; Heinonen, Olle; Benali, Anouar; Kwon, Yongkyung

2017-01-01

α-graphyne is a two-dimensional sheet of sp-sp2 hybridized carbon atoms in a honeycomb lattice. While the geometrical structure is similar to that of graphene, the hybridized triple bonds give rise to electronic structure that is different from that of graphene. Similar to graphene, α-graphyne can be stacked in bilayers with two stable configurations, but the different stackings have very different electronic structures: one is predicted to have gapless parabolic bands and the other a tunable bandgap which is attractive for applications. In order to realize applications, it is crucial to understand which stacking is more stable. This is difficult to model, as the stability is a result of weak interlayer van der Waals interactions which are not well captured by density functional theory (DFT). We have used quantum Monte Carlo simulations that accurately include van der Waals interactions to calculate the interlayer binding energy of bilayer graphyne and to determine its most stable stacking mode. Our results show that inter-layer bindings of sp- and sp2-bonded carbon networks are significantly underestimated in a Kohn-Sham DFT approach, even with an exchange-correlation potential corrected to include, in some approximation, van der Waals interactions. Finally, our quantum Monte Carlo calculations reveal that the interlayer binding energy difference between the two stacking modes is only 0.9(4) eV/atom. From this we conclude that the two stable stacking modes of bilayer α-graphyne are almost degenerate with each other, and both will occur with about the same probability at room temperature unless there is a synthesis path that prefers one stacking over the other.

Global seismic inversion as the next standard step in the processing sequence

Energy Technology Data Exchange (ETDEWEB)

Maver, Kim G.; Hansen, Lars S.; Jepsen, Anne-Marie; Rasmussen, Klaus B.

1998-12-31

Seismic inversion of post stack seismic data has until recently been regarded as a reservoir oriented method since the standard inversion techniques rely on extensive well control and a detailed user derived input model. Most seismic inversion techniques further requires a stable wavelet. As a consequence seismic inversion is mainly utilised in mature areas focusing of specific zones only after the seismic data has been interpreted and is well understood. By using an advanced 3-D global technique, seismic inversion is presented as the next standard step in the processing sequence. The technique is robust towards noise within the seismic data, utilizes a time variant wavelet, and derives a low frequency model utilizing the stacking velocities and only limited well control. 4 figs.

Stack Parameters Effect on the Performance of Anharmonic Resonator Thermoacoustic Heat Engine

KAUST Repository

Nouh, Mostafa A.

2014-01-01

A thermoacoustic heat engine (TAHE) converts heat into acoustic power with no moving parts. It exhibits several advantages over traditional engines, such as simple design, stable functionality, and environment-friendly working gas. In order to further improve the performance of TAHE, stack parameters need to be optimized. Stack\\'s position, length and plate spacing are the three main parameters that have been investigated in this study. Stack\\'s position dictates both the efficiency and the maximum produced acoustic power of the heat engine. Positioning the stack closer to the pressure anti-node might ensure high efficiency on the expense of the maximum produced acoustic power. It is noticed that the TAHE efficiency can further be improved by spacing the plates of the stack at a value of 2.4 of the thermal penetration depth, δk . Changes in the stack length will not affect the efficiency much as long as the temperature gradient across the stack, as a ratio of the critical temperature gradient ψ is more than 1. Upon interpreting the effect of these variations, attempts are made towards reaching the engine\\'s most powerful operating point.

Mutation Scanning in a Single and a Stacked Genetically Modified (GM) Event by Real-Time PCR and High Resolution Melting (HRM) Analysis

Science.gov (United States)

Ben Ali, Sina-Elisabeth; Madi, Zita Erika; Hochegger, Rupert; Quist, David; Prewein, Bernhard; Haslberger, Alexander G.; Brandes, Christian

2014-01-01

Genetic mutations must be avoided during the production and use of seeds. In the European Union (EU), Directive 2001/18/EC requires any DNA construct introduced via transformation to be stable. Establishing genetic stability is critical for the approval of genetically modified organisms (GMOs). In this study, genetic stability of two GMOs was examined using high resolution melting (HRM) analysis and real-time polymerase chain reaction (PCR) employing Scorpion primers for amplification. The genetic variability of the transgenic insert and that of the flanking regions in a single oilseed rape variety (GT73) and a stacked maize (MON88017 × MON810) was studied. The GT73 and the 5' region of MON810 showed no instabilities in the examined regions. However; two out of 100 analyzed samples carried a heterozygous point mutation in the 3' region of MON810 in the stacked variety. These results were verified by direct sequencing of the amplified PCR products as well as by sequencing of cloned PCR fragments. The occurrence of the mutation suggests that the 5' region is more suitable than the 3' region for the quantification of MON810. The identification of the single nucleotide polymorphism (SNP) in a stacked event is in contrast to the results of earlier studies of the same MON810 region in a single event where no DNA polymorphism was found. PMID:25365178

Relative role of transfer zones in controlling sequence stacking patterns and facies distribution: insights from the Fushan Depression, South China Sea

Science.gov (United States)

Liu, Entao; Wang, Hua; Li, Yuan; Huang, Chuanyan

2015-04-01

In sedimentary basins, a transfer zone can be defined as a coordinated system of deformational features which has good prospects for hydrocarbon exploration. Although the term 'transfer zone' has been widely applied to the study of extensional basins, little attention has been paid to its controlling effect on sequence tracking pattern and depositional facies distribution. Fushan Depression is a half-graben rift sub-basin, located in the southeast of the Beibuwan Basin, South China Sea. In this study, comparative analysis of seismic reflection, palaeogeomorphology, fault activity and depositional facies distribution in the southern slope indicates that three different types of sequence stacking patterns (i.e. multi-level step-fault belt in the western area, flexure slope belt in the central area, gentle slope belt in the eastern area) were developed along the southern slope, together with a large-scale transfer zone in the central area, at the intersection of the western and eastern fault systems. Further analysis shows that the transfer zone played an important role in the diversity of sequence stacking patterns in the southern slope by dividing the Fushan Depression into two non-interfering tectonic systems forming different sequence patterns, and leading to the formation of the flexure slope belt in the central area. The transfer zone had an important controlling effect on not only the diversity of sequence tracking patterns, but also the facies distribution on the relay ramp. During the high-stand stage, under the controlling effect of the transfer zone, the sediments contain a significant proportion of coarser material accumulated and distributed along the ramp axis. By contrast, during the low-stand stage, the transfer zone did not seem to contribute significantly to the low-stand fan distribution which was mainly controlled by the slope gradient (palaeogeomorphology). Therefore, analysis of the transfer zone can provide a new perspective for basin analysis

Dependence of intermetallic compound formation on the sublayer stacking sequence in Ag–Sn bilayer thin films

International Nuclear Information System (INIS)

Rossi, P.J.; Zotov, N.; Bischoff, E.; Mittemeijer, E.J.

2016-01-01

Intermetallic compound (IMC) formation in thermally-evaporated Ag–Sn bilayer thin films has been investigated employing especially X-ray diffraction (XRD) and (S)TEM methods. The specific IMCs that are present in the as-deposited state depend sensitively on the stacking sequence of the sublayers. In case of Sn on top of Ag, predominantly Ag 3 Sn is formed, whereas Ag 4 Sn is predominantly present in the as-deposited state for Ag on top of Sn. In the latter case this is accompanied by an extremely fast uptake of a large amount of Sn by the Ag sublayer, leaving behind macroscopic voids in the Sn sublayer. The results are discussed on the basis of the thermodynamics and kinetics of (IMC) product-layer growth in thin films. It is shown that both thermodynamic and kinetic arguments explain the contrasting phenomena observed.

Computation of the lamina stacking sequence effect on elastic moduli of a plain-weave Nicalon/SiC laminated composite with a [0/30/60] lay-up

International Nuclear Information System (INIS)

Zhao Wei; Yu Niann-i

1998-01-01

Estimation of the elastic modulus is important in engineering design. One difference between CFCCs (continuous fiber-reinforced ceramic-matrix composites), and CMCs (whisker, particulate, or short fiber-reinforced ceramic-matrix composites), is that the anisotropic behavior of CFCCs plays an important role in affecting their mechanical behavior. This feature may also contribute to the variation of elastic properties and strengths of CFCC. In this paper, a Fortran program is developed to quantify the lamina stacking sequence effect on the effective elastic moduli of the laminated CFCCs. The material for modeling is a plain-weave Nicalon fiber-reinforced silicon carbide (Nicalon/SiC) CFCCs. Results show that various stacking sequences within the CFCC (a [0/30/60] lay-up) will give different effective elastic moduli of the CFCCs. This trend leads to a variation of the slope of the linear portion on the flexural stress-strain curve, i.e., changing the position of the starting point of the non-linear portion, and the shape of the whole curve, which gives a different value of the peak stress in the curve. (orig.)

The effects of stacking sequence and thermal cycling on the flexural properties of laminate composites of aluminium-epoxy/basalt-glass fibres

Science.gov (United States)

Abdollahi Azghan, Mehdi; Eslami-Farsani, Reza

2018-02-01

The current study aimed at investigating the effects of different stacking sequences and thermal cycling on the flexural properties of fibre metal laminates (FMLs). FMLs were composed of two aluminium alloy 2024-T3 sheets and epoxy polymer-matrix composites that have four layers of basalt and/or glass fibres with five different stacking sequences. For FML samples the thermal cycle time was about 6 min for temperature cycles from 25 °C to 115 °C. Flexural properties of samples evaluated after 55 thermal cycles and compared to non-exposed samples. Surface modification of aluminium performed by electrochemical treatment (anodizing) method and aluminium surfaces have been examined by scanning electron microscopy (SEM). Also, the flexural failure mechanisms investigated by the optical microscope study of fractured surfaces. SEM images indicated that the porosity of the aluminium surface increased after anodizing process. The findings of the present study showed that flexural modulus were maximum for basalt fibres based FML, minimum for glass fibres based FML while basalt/glass fibres based FML lies between them. Due to change in the failure mechanism of basalt/glass fibres based FMLs that have glass fibres at outer layer of the polymer composite, the flexural strength of this FML is lower than glass and basalt fibres based FML. After thermal cycling, due to the good thermal properties of basalt fibres, flexural properties of basalt fibres based FML structures decreased less than other composites.

Stack Parameters Effect on the Performance of Anharmonic Resonator Thermoacoustic Heat Engine

KAUST Repository

Nouh, Mostafa A.; Arafa, Nadim M.; Abdel-Rahman, Ehab

2014-01-01

A thermoacoustic heat engine (TAHE) converts heat into acoustic power with no moving parts. It exhibits several advantages over traditional engines, such as simple design, stable functionality, and environment-friendly working gas. In order to further improve the performance of TAHE, stack parameters need to be optimized. Stack's position, length and plate spacing are the three main parameters that have been investigated in this study. Stack's position dictates both the efficiency and the maximum produced acoustic power of the heat engine. Positioning the stack closer to the pressure anti-node might ensure high efficiency on the expense of the maximum produced acoustic power. It is noticed that the TAHE efficiency can further be improved by spacing the plates of the stack at a value of 2.4 of the thermal penetration depth, δk . Changes in the stack length will not affect the efficiency much as long as the temperature gradient across the stack, as a ratio of the critical temperature gradient ψ is more than 1. Upon interpreting the effect of these variations, attempts are made towards reaching the engine's most powerful operating point.

Electricity generation and microbial community in response to short-term changes in stack connection of self-stacked submersible microbial fuel cell powered by glycerol

DEFF Research Database (Denmark)

Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

2017-01-01

community. In this study, a self-stacked submersible microbial fuel cell (SSMFC) powered by glycerol was tested to elucidate this important issue. In series connection, the maximum voltage output reached to 1.15 V, while maximum current density was 5.73 mA in parallel. In both connections, the maximum power......Stack connection (i.e., in series or parallel) of microbial fuel cell (MFC) is an efficient way to boost the power output for practical application. However, there is little information available on short-term changes in stack connection and its effect on the electricity generation and microbial...... density increased with the initial glycerol concentration. However, the glycerol degradation was even faster in parallel connection. When the SSMFC was shifted from series to parallel connection, the reactor reached to a stable power output without any lag phase. Meanwhile, the anodic microbial community...

Charge transfer in pi-stacked systems including DNA

International Nuclear Information System (INIS)

Siebbeles, L.D.A.

2003-01-01

Charge migration in DNA is a subject of intense current study motivated by long-range detection of DNA damage and the potential application of DNA as a molecular wire in nanoscale electronic devices. A key structural element, which makes DNA a medium for long-range charge transfer, is the array of stacked base pairs in the interior of the double helix. The overlapping pi-orbitals of the nucleobases provide a pathway for motion of charge carriers generated on the stack. This 'pi-pathway' resembles the columnarly stacked macrocyclic cores in discotic materials such as triphenylenes. The structure of these pi-stacked systems is highly disordered with dynamic fluctuations occurring on picosecond to nanosecond time scales. Theoretical calculations, concerning the effects of structural disorder and nucleobase sequence in DNA, on the dynamics of charge carriers are presented. Electronic couplings and localization energies of charge carriers were calculated using density functional theory (DFT). Results for columnarly stacked triphenylenes and DNA nucleobases are compared. The results are used to provide insight into the factors that control the mobility of charge carriers. Further, experimental results on the site-selective oxidation of guanine nucleobases in DNA (hot spots for DNA damage) are analyzed on basis of the theoretical results

Ab initio study on stacking sequences, free energy, dynamical stability and potential energy surfaces of graphite structures

International Nuclear Information System (INIS)

Anees, P; Valsakumar, M C; Chandra, Sharat; Panigrahi, B K

2014-01-01

Ab initio simulations have been performed to study the structure, energetics and stability of several plausible stacking sequences in graphite. These calculations suggest that in addition to the standard structures, graphite can also exist in AA-simple hexagonal, AB-orthorhombic and ABC-hexagonal type stacking. The free energy difference between these structures is very small (∼1 meV/atom), and hence all the structures can coexist from purely energetic considerations. Calculated x-ray diffraction patterns are similar to those of the standard structures for 2θ ⩽ 70°. Shear elastic constant C 44 is negative in AA-simple hexagonal, AB-orthorhombic and ABC-hexagonal structures, suggesting that these structures are mechanically unstable. Phonon dispersions show that the frequencies of some modes along the Γ–A direction in the Brillouin zone are imaginary in all of the new structures, implying that these structures are dynamically unstable. Incorporation of zero point vibrational energy via the quasi-harmonic approximation does not result in the restoration of dynamical stability. Potential energy surfaces for the unstable normal modes are seen to have the topography of a potential hill for all the new structures, confirming that all of the new structures are inherently unstable. The fact that the potential energy surface is not in the form of a double well implies that the structures are linearly as well as globally unstable. (paper)

Revisiting the origin of the preferential π-π stacking conformation of the (+)-8-phenylmenthyl acrylate

International Nuclear Information System (INIS)

Capim, Saulo L.; Santana, Sidney R.; Oliveira, Boaz G. de; Rocha, Gerd B.; Vasconcellos, Mario L.A.A

2010-01-01

In this paper we report a theoretical study aiming to revisit the origin of the preferential π-π stacking conformation of the (+)-8-phenylmenthyl acrylate (2). For this, we have applied several DFT and ab initio methods to calculate local minimum geometries, vibrational frequencies, thermochemical properties and 1 H NMR chemical shifts for 2 and the model compound 3-phenylpropyl acrylate (3). We have observed that the MPW1B95 functional was the most suitable method to explain 1 H NMR experimental data which show the stacking conformation of 2 (2S) is more stable that trans conformation (2T) and the stacking conformation of 3 (3S) is less stable that trans conformation (3T). After that, geometrical and energetic features of the intermolecular complex benzene...methylacrylate (4) have also been studied using MPW1B95 method. From our results, we have noticed that both steric and dispersion effects play a key role in the conformational equilibrium of 2. (author)

Ab-initio calculation of electronic structure and optical properties of AB-stacked bilayer α-graphyne

Science.gov (United States)

Behzad, Somayeh

2016-09-01

Monolayer α-graphyne is a new two-dimensional carbon allotrope with many special features. In this work the electronic properties of AA- and AB-stacked bilayers of this material and then the optical properties are studied, using first principle plane wave method. The electronic spectrum has two Dirac cones for AA stacked bilayer α-graphyne. For AB-stacked bilayer, the interlayer interaction changes the linear bands into parabolic bands. The optical spectra of the most stable AB-stacked bilayer closely resemble to that of the monolayer, except for small shifts of peak positions and increasing of their intensity. For AB-stacked bilayer, a pronounced peak has been found at low energies under the perpendicular polarization. This peak can be clearly ascribed to the transitions at the Dirac point as a result of the small degeneracy lift in the band structure.

Experimental and Numerical Studies on Fiber Deformation and Formability in Thermoforming Process Using a Fast-Cure Carbon Prepreg: Effect of Stacking Sequence and Mold Geometry

Directory of Open Access Journals (Sweden)

Daeryeong Bae

2018-05-01

Full Text Available A fast-cure carbon fiber/epoxy prepreg was thermoformed against a replicated automotive roof panel mold (square-cup to investigate the effect of the stacking sequence of prepreg layers with unidirectional and plane woven fabrics and mold geometry with different drawing angles and depths on the fiber deformation and formability of the prepreg. The optimum forming condition was determined via analysis of the material properties of epoxy resin. The non-linear mechanical properties of prepreg at the deformation modes of inter- and intra-ply shear, tensile and bending were measured to be used as input data for the commercial virtual forming simulation software. The prepreg with a stacking sequence containing the plain-woven carbon prepreg on the outer layer of the laminate was successfully thermoformed against a mold with a depth of 20 mm and a tilting angle of 110°. Experimental results for the shear deformations at each corner of the thermoformed square-cup product were compared with the simulation and a similarity in the overall tendency of the shear angle in the path at each corner was observed. The results are expected to contribute to the optimization of parameters on materials, mold design and processing in the thermoforming mass-production process for manufacturing high quality automotive parts with a square-cup geometry.

Experimental and Numerical Studies on Fiber Deformation and Formability in Thermoforming Process Using a Fast-Cure Carbon Prepreg: Effect of Stacking Sequence and Mold Geometry

Science.gov (United States)

Bae, Daeryeong; Kim, Shino; Lee, Wonoh; Yi, Jin Woo; Um, Moon Kwang; Seong, Dong Gi

2018-01-01

A fast-cure carbon fiber/epoxy prepreg was thermoformed against a replicated automotive roof panel mold (square-cup) to investigate the effect of the stacking sequence of prepreg layers with unidirectional and plane woven fabrics and mold geometry with different drawing angles and depths on the fiber deformation and formability of the prepreg. The optimum forming condition was determined via analysis of the material properties of epoxy resin. The non-linear mechanical properties of prepreg at the deformation modes of inter- and intra-ply shear, tensile and bending were measured to be used as input data for the commercial virtual forming simulation software. The prepreg with a stacking sequence containing the plain-woven carbon prepreg on the outer layer of the laminate was successfully thermoformed against a mold with a depth of 20 mm and a tilting angle of 110°. Experimental results for the shear deformations at each corner of the thermoformed square-cup product were compared with the simulation and a similarity in the overall tendency of the shear angle in the path at each corner was observed. The results are expected to contribute to the optimization of parameters on materials, mold design and processing in the thermoforming mass-production process for manufacturing high quality automotive parts with a square-cup geometry. PMID:29883413

Short-Range Stacking Disorder in Mixed-Layer Compounds: A HAADF STEM Study of Bastnäsite-Parisite Intergrowths

Directory of Open Access Journals (Sweden)

Cristiana L. Ciobanu

2017-11-01

Full Text Available Atomic-scale high angle annular dark field scanning transmission electron microscopy (HAADF STEM imaging and electron diffractions are used to address the complexity of lattice-scale intergrowths of REE-fluorocarbonates from an occurrence adjacent to the Olympic Dam deposit, South Australia. The aims are to define the species present within the intergrowths and also assess the value of the HAADF STEM technique in resolving stacking sequences within mixed-layer compounds. Results provide insights into the definition of species and crystal-structural modularity. Lattice-scale intergrowths account for the compositional range between bastnäsite and parasite, as measured by electron probe microanalysis (at the µm-scale throughout the entire area of the intergrowths. These comprise rhythmic intervals of parisite and bastnäsite, or stacking sequences with gradational changes in the slab stacking between B, BBS and BS types (B—bastnäsite, S—synchysite. An additional occurrence of an unnamed B2S phase [CaCe3(CO34F3], up to 11 unit cells in width, is identified among sequences of parisite and bastnäsite within the studied lamellar intergrowths. Both B2S and associated parisite show hexagonal lattices, interpreted as 2H polytypes with c = 28 and 38 Å, respectively. 2H parisite is a new, short hexagonal polytype that can be added to the 14 previously reported polytypes (both hexagonal and rhombohedral for this mineral. The correlation between satellite reflections and the number of layers along the stacking direction (c* can be written empirically as: Nsat = [(m × 2 + (n × 4] − 1 for all BmSn compounds with S ≠ 0. The present study shows intergrowths characterised by short-range stacking disorder and coherent changes in stacking along perpendicular directions. Knowing that the same compositional range can be expressed as long-period stacking compounds in the group, the present intergrowths are interpreted as being related to disequilibrium

New approach for dynamic flow management within the PEMFC stack

International Nuclear Information System (INIS)

Varlam, Mihai; Culcer, Mihai; Carcadea, Elena; Stefanescu, Ioan; Iliescu, Mariana; Enache, Adrian

2009-01-01

An adequate gas and water flow management is a key issue to reach and maintain a higher output power for a PEM fuel cell stack. One of the main aspects which could limit the performance of a PEM fuel cell stack is the weak capability for a non-uniform water distribution management within the fuel cell. The produced water could become a handicap to attain the best working performance by blocking the catalytic surfaces and by preventing the mass transport process. Usually, the excess water is removed in one cell, comparatively to others from the stack and taking into account that all the cells are supplied in parallel from a common air admission pipe, a limitation of gas flow rate within that cell is created. Consequently, this constraint will reduce further the water removal speed. This feedback process will generate finally a drastic decrease of the fuel cell stack performance. A new practical solution to this water and gas non-uniformity of distributions problem is to use a sequential purge procedure of several fuel cell groups inside the stack which could guarantee a right management of water. An experimental setup has been built based on four fuel cell stack. Every fuel cell was connected to a single removal pipe via a solenoid valve. A computer-controlled hardware and software system has been designed and built, in order to generate a given opening-closing sequence for the automatic valve system. (authors)

Genome Sequence of Pseudomonas aeruginosa Strain DK1-NH57388A, a Stable Mucoid Cystic Fibrosis Isolate

DEFF Research Database (Denmark)

Norman, Anders; Ciofu, Oana; Amador Hierro, Cristina Isabel

2016-01-01

Pseudomonas aeruginosa is an important opportunistic pathogen associated with chronic pulmonary infections and mortality in cystic fibrosis (CF) patients. Here, we present the complete genome sequence of stable mucoid P. aeruginosa strain DK1-NH57388A, a CF isolate which has previously been used...

Stacking with stochastic cooling

Energy Technology Data Exchange (ETDEWEB)

Caspers, Fritz E-mail: Fritz.Caspers@cern.ch; Moehl, Dieter

2004-10-11

Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 10{sup 5} the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some

Enhanced optical fields in a multilayered microsphere with a quasiperiodic spherical stack

International Nuclear Information System (INIS)

Burlak, Gennadiy N

2007-01-01

Radiation of a nanosource placed in a microsphere with a quasiperiodic subwavelength spherical stack is studied. The spectral evolution of transmittance at the change of the thickness of two-layer blocks constructed following the Fibonacci sequence is investigated. When the number of layers (Fibonacci order) increases the structure of the spectrum acquires a fractal form. Our calculations show a rising strong field peak, when the ratio of width of layers in two-layer blocks of the stack is close to the golden mean value

EmuStack: An OpenStack-Based DTN Network Emulation Platform (Extended Version

Directory of Open Access Journals (Sweden)

Haifeng Li

2016-01-01

Full Text Available With the advancement of computing and network virtualization technology, the networking research community shows great interest in network emulation. Compared with network simulation, network emulation can provide more relevant and comprehensive details. In this paper, EmuStack, a large-scale real-time emulation platform for Delay Tolerant Network (DTN, is proposed. EmuStack aims at empowering network emulation to become as simple as network simulation. Based on OpenStack, distributed synchronous emulation modules are developed to enable EmuStack to implement synchronous and dynamic, precise, and real-time network emulation. Meanwhile, the lightweight approach of using Docker container technology and network namespaces allows EmuStack to support a (up to hundreds of nodes large-scale topology with only several physical nodes. In addition, EmuStack integrates the Linux Traffic Control (TC tools with OpenStack for managing and emulating the virtual link characteristics which include variable bandwidth, delay, loss, jitter, reordering, and duplication. Finally, experiences with our initial implementation suggest the ability to run and debug experimental network protocol in real time. EmuStack environment would bring qualitative change in network research works.

Stacking stability of MoS2 bilayer: An ab initio study

International Nuclear Information System (INIS)

Tao Peng; Guo Huai-Hong; Yang Teng; Zhang Zhi-Dong

2014-01-01

The study of the stacking stability of bilayer MoS 2 is essential since a bilayer has exhibited advantages over single layer MoS 2 in many aspects for nanoelectronic applications. We explored the relative stability, optimal sliding path between different stacking orders of bilayer MoS 2 , and (especially) the effect of inter-layer stress, by combining first-principles density functional total energy calculations and the climbing-image nudge-elastic-band (CI-NEB) method. Among five typical stacking orders, which can be categorized into two kinds (I: AA, AB and II: AA', AB', A'B), we found that stacking orders with Mo and S superposing from both layers, such as AA' and AB, is more stable than the others. With smaller computational efforts than potential energy profile searching, we can study the effect of inter-layer stress on the stacking stability. Under isobaric condition, the sliding barrier increases by a few eV/(ucGPa) from AA' to AB', compared to 0.1 eV/(ucGPa) from AB to [AB]. Moreover, we found that interlayer compressive stress can help enhance the transport properties of AA'. This study can help understand why inter-layer stress by dielectric gating materials can be an effective means to improving MoS 2 on nanoelectronic applications. (condensed matter: structural, mechanical, and thermal properties)

Direct stacking of sequence-specific nuclease-induced mutations to produce high oleic and low linolenic soybean oil.

Science.gov (United States)

Demorest, Zachary L; Coffman, Andrew; Baltes, Nicholas J; Stoddard, Thomas J; Clasen, Benjamin M; Luo, Song; Retterath, Adam; Yabandith, Ann; Gamo, Maria Elena; Bissen, Jeff; Mathis, Luc; Voytas, Daniel F; Zhang, Feng

2016-10-13

The ability to modulate levels of individual fatty acids within soybean oil has potential to increase shelf-life and frying stability and to improve nutritional characteristics. Commodity soybean oil contains high levels of polyunsaturated linoleic and linolenic acid, which contribute to oxidative instability - a problem that has been addressed through partial hydrogenation. However, partial hydrogenation increases levels of trans-fatty acids, which have been associated with cardiovascular disease. Previously, we generated soybean lines with knockout mutations within fatty acid desaturase 2-1A (FAD2-1A) and FAD2-1B genes, resulting in oil with increased levels of monounsaturated oleic acid (18:1) and decreased levels of linoleic (18:2) and linolenic acid (18:3). Here, we stack mutations within FAD2-1A and FAD2-1B with mutations in fatty acid desaturase 3A (FAD3A) to further decrease levels of linolenic acid. Mutations were introduced into FAD3A by directly delivering TALENs into fad2-1a fad2-1b soybean plants. Oil from fad2-1a fad2-1b fad3a plants had significantly lower levels of linolenic acid (2.5 %), as compared to fad2-1a fad2-1b plants (4.7 %). Furthermore, oil had significantly lower levels of linoleic acid (2.7 % compared to 5.1 %) and significantly higher levels of oleic acid (82.2 % compared to 77.5 %). Transgene-free fad2-1a fad2-1b fad3a soybean lines were identified. The methods presented here provide an efficient means for using sequence-specific nucleases to stack quality traits in soybean. The resulting product comprised oleic acid levels above 80 % and linoleic and linolenic acid levels below 3 %.

Initiation and Performance of a Coating for Countering Chromium Poisoning in a SOFC-stack

DEFF Research Database (Denmark)

Nielsen, Karsten Agersted; Persson, Åsa Helen; Beeaff, Dustin

2007-01-01

Minimising transport of chromium from the metallic interconnect (e.g. of Crofer 22APU) to the cathode in a planar solid oxide fuel cell is done by application of a coating between the two parts. The coating is applied by slurry coating, and taken through stack initialisation it transforms...... into a stable and densely grown barrier layer, which minimises both the evaporation of chromium from the interconnect surface and the electrical contact resistance between the interconnect and the cathode. Between comparable stack element tests with and without coatings at 750 degrees C, the degradation rate...

The effect of edge interlaminar stresses on the strength of carbon/epoxy laminates of different stacking geometry

OpenAIRE

MOMCILO STEVANOVIC; MILAN GORDIC; DANIELA SEKULIC; ISIDOR DJORDJEVIC

2006-01-01

The effect of edge interlaminar stresses on strength of carbon/epoxy laminates of different stacking geometry: cross-ply, quasi-isotropic and angle-ply laminates with additional 0º and 90º ply was studied. Coupons with two widths of laminates with an inverse stacking sequence were tested in static tensile tests. The effect of edge interlaminar stresses on strength was studied, by comparing the values of the tensile strength of laminate coupons of the same width with an inverse stacking sequen...

Algebraic stacks

Indian Academy of Sciences (India)

Deligne, Mumford and Artin [DM, Ar2]) and consider algebraic stacks, then we can cons- truct the 'moduli ... the moduli scheme and the moduli stack of vector bundles. First I will give ... 1–31. © Printed in India. 1 ...... Cultura, Spain. References.

Self-assembly of bimetallic AuxPd1-x alloy nanoparticles via dewetting of bilayers through the systematic control of temperature, thickness, composition and stacking sequence

Science.gov (United States)

Kunwar, Sundar; Pandey, Puran; Sui, Mao; Bastola, Sushil; Lee, Jihoon

2018-03-01

Bimetallic alloy nanoparticles (NPs) are attractive materials for various applications with their morphology and elemental composition dependent optical, electronic, magnetic and catalytic properties. This work demonstrates the evolution of AuxPd1-x alloy nanostructures by the solid-state dewetting of sequentially deposited bilayers of Au and Pd on sapphire (0001). Various shape, size and configuration of AuxPd1‑x alloy NPs are fabricated by the systematic control of annealing temperature, deposition thickness, composition as well as stacking sequence. The evolution of alloy nanostructures is attributed to the surface diffusion, interface diffusion between bilayers, surface and interface energy minimization, Volmer-Weber growth model and equilibrium configuration. Depending upon the temperature, the surface morphologies evolve with the formation of pits, grains and voids and gradually develop into isolated semi-spherical alloy NPs by the expansion of voids and agglomeration of Au and Pd adatoms. On the other hand, small isolated to enlarged elongated and over-grown layer-like alloy nanostructures are fabricated due to the coalescence, partial diffusion and inter-diffusion with the increased bilayer thickness. In addition, the composition and stacking sequence of bilayers remarkably affect the final geometry of AuxPd1‑x nanostructures due to the variation in the dewetting process. The optical analysis based on the UV–vis-NIR reflectance spectra reveals the surface morphology dependent plasmonic resonance, scattering, reflection and absorption properties of AuxPd1‑x alloy nanostructures.

StackGAN++: Realistic Image Synthesis with Stacked Generative Adversarial Networks

OpenAIRE

Zhang, Han; Xu, Tao; Li, Hongsheng; Zhang, Shaoting; Wang, Xiaogang; Huang, Xiaolei; Metaxas, Dimitris

2017-01-01

Although Generative Adversarial Networks (GANs) have shown remarkable success in various tasks, they still face challenges in generating high quality images. In this paper, we propose Stacked Generative Adversarial Networks (StackGAN) aiming at generating high-resolution photo-realistic images. First, we propose a two-stage generative adversarial network architecture, StackGAN-v1, for text-to-image synthesis. The Stage-I GAN sketches the primitive shape and colors of the object based on given...

Evidence of a non-dimensional parameter controlling the flooding of PEMFC stack

Energy Technology Data Exchange (ETDEWEB)

Buaud, Fabrice; Lelandais, Damien [Heat and Energy Department, Polytech' Nantes, Nantes University, Rue Christian Pauc, BP50609, 44 306 Nantes Cedex 3 (France); Auvity, Bruno [Heat and Energy Department, Polytech' Nantes, Nantes University, Rue Christian Pauc, BP50609, 44 306 Nantes Cedex 3 (France); Laboratoire de Thermocinetique de Nantes (CNRS-UMR 6607) (France)

2008-06-15

Water management is a key issue to get satisfactory and stable Polymer exchange membrane fuel cell (PEMFC) performances. The work reported in the present paper focuses on the determination of the operational conditions when using PEMFC stack working with ambient air without extra humidification. The objectives are to reduce as much as possible the auxiliaries consumptions. As far as the reaction air blower is concerned, the specific goal of the present tests is to find the minimum air flow rate to feed the PEMFC stack in order to prevent flooding. Our particular interest concerns the control of a PEMFC stack to power a prototype vehicle for the Shell Eco Marathon race. Tests are then conducted on a wide range of stoichiometry, for different values of current and stack temperature using ambient air. Flooding is shown to depend on all these parameters. A water balance calculation is developed comparing the amount of water produced by the electrochemical reaction to the amount of water transported as vapour in the exit air flow minus the amount of water incoming the stack in the ambient air. A non-dimensional number called the Flooding Number is constructed. This balance is first considered in the ideal case with the theoretical flow rate of reactants and products. It is shown that the stack temperature and the stoichiometry are the main order parameters and that conditions of ambient air have only secondary effects on the water balance. In a second step, the Flooding Number is evaluated for all the experimental tests. A critical Flooding Number appears clearly delimiting the range of operational conditions for which stack flooding appears. This result allows us to control the air blower and the cooling fan during the runs at the Shell Eco Marathon 2007 race in order to reduce hydrogen consumption due to auxiliaries. The non-dimensional number exhibited in the present paper is believed to be relevant to stack flooding. It can be used for any PEMFC stack to make clear

Structure of a stacked anthraquinone–DNA complex

Science.gov (United States)

De Luchi, Daniela; Usón, Isabel; Wright, Glenford; Gouyette, Catherine; Subirana, Juan A.

2010-01-01

The crystal structure of the telomeric sequence d(UBrAGG) interacting with an anthraquinone derivative has been solved by MAD. In all previously studied complexes of intercalating drugs, the drug is usually sandwiched between two DNA base pairs. Instead, the present structure looks like a crystal of stacked anthraquinone molecules in which isolated base pairs are intercalated. Unusual base pairs are present in the structure, such as G·G and A·UBr reverse Watson–Crick base pairs. PMID:20823516

MSuPDA: A Memory Efficient Algorithm for Sequence Alignment.

Science.gov (United States)

Khan, Mohammad Ibrahim; Kamal, Md Sarwar; Chowdhury, Linkon

2016-03-01

Space complexity is a million dollar question in DNA sequence alignments. In this regard, memory saving under pushdown automata can help to reduce the occupied spaces in computer memory. Our proposed process is that anchor seed (AS) will be selected from given data set of nucleotide base pairs for local sequence alignment. Quick splitting techniques will separate the AS from all the DNA genome segments. Selected AS will be placed to pushdown automata's (PDA) input unit. Whole DNA genome segments will be placed into PDA's stack. AS from input unit will be matched with the DNA genome segments from stack of PDA. Match, mismatch and indel of nucleotides will be popped from the stack under the control unit of pushdown automata. During the POP operation on stack, it will free the memory cell occupied by the nucleotide base pair.

The Subwavelength Optical Field Confinement in a Multilayered Microsphere with Quasiperiodic Spherical Stack

Directory of Open Access Journals (Sweden)

Gennadiy N. Burlak

2008-01-01

Full Text Available We study the frequency spectrum of nanoemitters placed in a microsphere with a quasiperiodic subwavelength spherical stack. The spectral evolution of transmittancy at the change of thickness of two-layer blocks, constructed following the Fibonacci sequence, is investigated. When the number of layers (Fibonacci order increases, the structure of spectrum acquires a fractal form. Our calculations show the radiation confinement and gigantic field enhancement, when the ratio of layers’ widths in twolayer blocks of the stack is close to the golden mean value.

STACKING ON COMMON REFLECTION SURFACE WITH MULTIPARAMETER TRAVELTIME

Directory of Open Access Journals (Sweden)

Montes V. Luis A.

2006-12-01

Full Text Available Commonly seismic images are displayed in time domain because the model in depth can be known only in well logs. To produce seismic sections, pre and post stack processing approaches use time or depth velocity models whereas the common reflection method does not, instead it requires a set of parameters established for the first layer. A set of synthetic data of an anticline model, with sources and receivers placed on a flat topography, was used to observe the performance of this method. As result, a better reflector recovering compared against conventional processing sequence was observed.
The procedure was extended to real data, using a dataset acquired on a zone characterized by mild topography and quiet environment reflectors in the Eastern Colombia planes, observing an enhanced and a better continuity of the reflectors in the CRS stacked section.

CodonLogo: a sequence logo-based viewer for codon patterns.

Science.gov (United States)

Sharma, Virag; Murphy, David P; Provan, Gregory; Baranov, Pavel V

2012-07-15

Conserved patterns across a multiple sequence alignment can be visualized by generating sequence logos. Sequence logos show each column in the alignment as stacks of symbol(s) where the height of a stack is proportional to its informational content, whereas the height of each symbol within the stack is proportional to its frequency in the column. Sequence logos use symbols of either nucleotide or amino acid alphabets. However, certain regulatory signals in messenger RNA (mRNA) act as combinations of codons. Yet no tool is available for visualization of conserved codon patterns. We present the first application which allows visualization of conserved regions in a multiple sequence alignment in the context of codons. CodonLogo is based on WebLogo3 and uses the same heuristics but treats codons as inseparable units of a 64-letter alphabet. CodonLogo can discriminate patterns of codon conservation from patterns of nucleotide conservation that appear indistinguishable in standard sequence logos. The CodonLogo source code and its implementation (in a local version of the Galaxy Browser) are available at http://recode.ucc.ie/CodonLogo and through the Galaxy Tool Shed at http://toolshed.g2.bx.psu.edu/.

OpenStack cloud security

CERN Document Server

Locati, Fabio Alessandro

2015-01-01

If you are an OpenStack administrator or developer, or wish to build solutions to protect your OpenStack environment, then this book is for you. Experience of Linux administration and familiarity with different OpenStack components is assumed.

Research on OpenStack of open source cloud computing in colleges and universities’ computer room

Science.gov (United States)

Wang, Lei; Zhang, Dandan

2017-06-01

In recent years, the cloud computing technology has a rapid development, especially open source cloud computing. Open source cloud computing has attracted a large number of user groups by the advantages of open source and low cost, have now become a large-scale promotion and application. In this paper, firstly we briefly introduced the main functions and architecture of the open source cloud computing OpenStack tools, and then discussed deeply the core problems of computer labs in colleges and universities. Combining with this research, it is not that the specific application and deployment of university computer rooms with OpenStack tool. The experimental results show that the application of OpenStack tool can efficiently and conveniently deploy cloud of university computer room, and its performance is stable and the functional value is good.

Stable and Selective Humidity Sensing Using Stacked Black Phosphorus Flakes.

Science.gov (United States)

Yasaei, Poya; Behranginia, Amirhossein; Foroozan, Tara; Asadi, Mohammad; Kim, Kibum; Khalili-Araghi, Fatemeh; Salehi-Khojin, Amin

2015-10-27

Black phosphorus (BP) atomic layers are known to undergo chemical degradation in humid air. Yet in more robust configurations such as films, composites, and embedded structures, BP can potentially be utilized in a large number of practical applications. In this study, we explored the sensing characteristics of BP films and observed an ultrasensitive and selective response toward humid air with a trace-level detection capability and a very minor drift over time. Our experiments show that the drain current of the BP sensor increases by ∼4 orders of magnitude as the relative humidity (RH) varies from 10% to 85%, which ranks it among the highest ever reported values for humidity detection. The mechanistic studies indicate that the operation principle of the BP film sensors is based on the modulation in the leakage ionic current caused by autoionization of water molecules and ionic solvation of the phosphorus oxoacids produced on moist BP surfaces. Our stability tests reveal that the response of the BP film sensors remains nearly unchanged after prolonged exposures (up to 3 months) to ambient conditions. This study opens up the route for utilizing BP stacked films in many potential applications such as energy generation/storage systems, electrocatalysis, and chemical/biosensing.

Can-Evo-Ens: Classifier stacking based evolutionary ensemble system for prediction of human breast cancer using amino acid sequences.

Science.gov (United States)

Ali, Safdar; Majid, Abdul

2015-04-01

The diagnostic of human breast cancer is an intricate process and specific indicators may produce negative results. In order to avoid misleading results, accurate and reliable diagnostic system for breast cancer is indispensable. Recently, several interesting machine-learning (ML) approaches are proposed for prediction of breast cancer. To this end, we developed a novel classifier stacking based evolutionary ensemble system "Can-Evo-Ens" for predicting amino acid sequences associated with breast cancer. In this paper, first, we selected four diverse-type of ML algorithms of Naïve Bayes, K-Nearest Neighbor, Support Vector Machines, and Random Forest as base-level classifiers. These classifiers are trained individually in different feature spaces using physicochemical properties of amino acids. In order to exploit the decision spaces, the preliminary predictions of base-level classifiers are stacked. Genetic programming (GP) is then employed to develop a meta-classifier that optimal combine the predictions of the base classifiers. The most suitable threshold value of the best-evolved predictor is computed using Particle Swarm Optimization technique. Our experiments have demonstrated the robustness of Can-Evo-Ens system for independent validation dataset. The proposed system has achieved the highest value of Area Under Curve (AUC) of ROC Curve of 99.95% for cancer prediction. The comparative results revealed that proposed approach is better than individual ML approaches and conventional ensemble approaches of AdaBoostM1, Bagging, GentleBoost, and Random Subspace. It is expected that the proposed novel system would have a major impact on the fields of Biomedical, Genomics, Proteomics, Bioinformatics, and Drug Development. Copyright © 2015 Elsevier Inc. All rights reserved.

The impact of stack geometry and mean pressure on cold end temperature of stack in thermoacoustic refrigeration systems

Science.gov (United States)

Wantha, Channarong

2018-02-01

This paper reports on the experimental and simulation studies of the influence of stack geometries and different mean pressures on the cold end temperature of the stack in the thermoacoustic refrigeration system. The stack geometry was tested, including spiral stack, circular pore stack and pin array stack. The results of this study show that the mean pressure of the gas in the system has a significant impact on the cold end temperature of the stack. The mean pressure of the gas in the system corresponds to thermal penetration depth, which results in a better cold end temperature of the stack. The results also show that the cold end temperature of the pin array stack decreases more than that of the spiral stack and circular pore stack geometry by approximately 63% and 70%, respectively. In addition, the thermal area and viscous area of the stack are analyzed to explain the results of such temperatures of thermoacoustic stacks.

OpenStack essentials

CERN Document Server

Radez, Dan

2015-01-01

If you need to get started with OpenStack or want to learn more, then this book is your perfect companion. If you're comfortable with the Linux command line, you'll gain confidence in using OpenStack.

Genome Sequence of Pseudomonas aeruginosa Strain DK1-NH57388A, a Stable Mucoid Cystic Fibrosis Isolate

DEFF Research Database (Denmark)

Norman, Anders; Ciofu, Oana; Amador Hierro, Cristina Isabel

2016-01-01

Pseudomonas aeruginosa is an important opportunistic pathogen associated with chronic pulmonary infections and mortality in cystic fibrosis (CF) patients. Here, we present the complete genome sequence of stable mucoid P. aeruginosa strain DK1-NH57388A, a CF isolate which has previously been used ...

Migration velocity analysis using pre-stack wave fields

KAUST Repository

Alkhalifah, Tariq Ali

2016-08-25

Using both image and data domains to perform velocity inversion can help us resolve the long and short wavelength components of the velocity model, usually in that order. This translates to integrating migration velocity analysis into full waveform inversion. The migration velocity analysis part of the inversion often requires computing extended images, which is expensive when using conventional methods. As a result, we use pre-stack wavefield (the double-square-root formulation) extrapolation, which includes the extended information (subsurface offsets) naturally, to make the process far more efficient and stable. The combination of the forward and adjoint pre-stack wavefields provides us with update options that can be easily conditioned to improve convergence. We specifically use a modified differential semblance operator to split the extended image into a residual part for classic differential semblance operator updates and the image (Born) modelling part, which provides reflections for higher resolution information. In our implementation, we invert for the velocity and the image simultaneously through a dual objective function. Applications to synthetic examples demonstrate the features of the approach.

Solid-state dewetting of Au-Ni bi-layer films mediated through individual layer thickness and stacking sequence

Science.gov (United States)

Herz, Andreas; Theska, Felix; Rossberg, Diana; Kups, Thomas; Wang, Dong; Schaaf, Peter

2018-06-01

In the present work, the solid-state dewetting of Au-Ni bi-layer thin films deposited on SiO2/Si is systematically studied with respect to individual layer thickness and stacking sequence. For this purpose, a rapid heat treatment at medium temperatures is applied in order to examine void formation at the early stages of the dewetting. Compositional variations are realized by changing the thickness ratio of the bi-layer films, while the total thickness is maintained at 20 nm throughout the study. In the event of Au/Ni films annealed at 500 °C, crystal voids exposing the substrate are missing regardless of chemical composition. In reverse order, the number of voids per unit area in two-phase Au-Ni thin films is found to be governed by the amount of Au-rich material. At higher temperatures up to 650 °C, a decreased probability of nucleation comes at the expense of a major portion of cavities, resulting in the formation of bubbles in 15 nm Ni/5 nm Au bi-layers. Film buckling predominantly occurred at phase boundaries crossing the bubbles.

Investigation of Ruthenium Dissolution in Advanced Membrane Electrode Assemblies for Direct Methanol Based Fuel Cell Stacks

Science.gov (United States)

Valdez, Thomas I.; Firdosy, S.; Koel, B. E.; Narayanan, S. R.

2005-01-01

Dissolution of ruthenium was observed in the 80-cell stack. Duration testing was performed in single cell MEAs to determine the pathway of cell degradation. EDAX analysis on each of the single cell MEAs has shown that the Johnson Matthey commercial catalyst is stable in DMFC operation for 250 hours, no ruthenium dissolution was observed. Changes in the hydrophobicity of the cathode backing papers was minimum. Electrode polarization analysis revealed that the MEA performance loss is attributed to changes in the cathode catalyst layer. Ruthenium migration does not seem to occur during cell operation but can occur when methanol is absent from the anode compartment, the cathode compartment has access to air, and the cells in the stack are electrically connected to a load (Shunt Currents). The open-to-air cathode stack design allowed for: a) The MEAs to have continual access to oxygen; and b) The stack to sustain shunt currents. Ruthenium dissolution in a DMFC stack can be prevented by: a) Developing an internally manifolded stacks that seal reactant compartments when not in operation; b) Bringing the cell voltages to zero quickly when not in operation; and c) Limiting the total number of cells to 25 in an effort to limit shunt currents.

Sequence periodicity in nucleosomal DNA and intrinsic curvature.

Science.gov (United States)

Nair, T Murlidharan

2010-05-17

Most eukaryotic DNA contained in the nucleus is packaged by wrapping DNA around histone octamers. Histones are ubiquitous and bind most regions of chromosomal DNA. In order to achieve smooth wrapping of the DNA around the histone octamer, the DNA duplex should be able to deform and should possess intrinsic curvature. The deformability of DNA is a result of the non-parallelness of base pair stacks. The stacking interaction between base pairs is sequence dependent. The higher the stacking energy the more rigid the DNA helix, thus it is natural to expect that sequences that are involved in wrapping around the histone octamer should be unstacked and possess intrinsic curvature. Intrinsic curvature has been shown to be dictated by the periodic recurrence of certain dinucleotides. Several genome-wide studies directed towards mapping of nucleosome positions have revealed periodicity associated with certain stretches of sequences. In the current study, these sequences have been analyzed with a view to understand their sequence-dependent structures. Higher order DNA structures and the distribution of molecular bend loci associated with 146 base nucleosome core DNA sequence from C. elegans and chicken have been analyzed using the theoretical model for DNA curvature. The curvature dispersion calculated by cyclically permuting the sequences revealed that the molecular bend loci were delocalized throughout the nucleosome core region and had varying degrees of intrinsic curvature. The higher order structures associated with nucleosomes of C.elegans and chicken calculated from the sequences revealed heterogeneity with respect to the deviation of the DNA axis. The results points to the possibility of context dependent curvature of varying degrees to be associated with nucleosomal DNA.

HTSSIP: An R package for analysis of high throughput sequencing data from nucleic acid stable isotope probing (SIP experiments.

Directory of Open Access Journals (Sweden)

Nicholas D Youngblut

Full Text Available Combining high throughput sequencing with stable isotope probing (HTS-SIP is a powerful method for mapping in situ metabolic processes to thousands of microbial taxa. However, accurately mapping metabolic processes to taxa is complex and challenging. Multiple HTS-SIP data analysis methods have been developed, including high-resolution stable isotope probing (HR-SIP, multi-window high-resolution stable isotope probing (MW-HR-SIP, quantitative stable isotope probing (qSIP, and ΔBD. Currently, there is no publicly available software designed specifically for analyzing HTS-SIP data. To address this shortfall, we have developed the HTSSIP R package, an open-source, cross-platform toolset for conducting HTS-SIP analyses in a straightforward and easily reproducible manner. The HTSSIP package, along with full documentation and examples, is available from CRAN at https://cran.r-project.org/web/packages/HTSSIP/index.html and Github at https://github.com/buckleylab/HTSSIP.

Revealing stable processing products from ribosome-associated small RNAs by deep-sequencing data analysis.

Science.gov (United States)

Zywicki, Marek; Bakowska-Zywicka, Kamilla; Polacek, Norbert

2012-05-01

The exploration of the non-protein-coding RNA (ncRNA) transcriptome is currently focused on profiling of microRNA expression and detection of novel ncRNA transcription units. However, recent studies suggest that RNA processing can be a multi-layer process leading to the generation of ncRNAs of diverse functions from a single primary transcript. Up to date no methodology has been presented to distinguish stable functional RNA species from rapidly degraded side products of nucleases. Thus the correct assessment of widespread RNA processing events is one of the major obstacles in transcriptome research. Here, we present a novel automated computational pipeline, named APART, providing a complete workflow for the reliable detection of RNA processing products from next-generation-sequencing data. The major features include efficient handling of non-unique reads, detection of novel stable ncRNA transcripts and processing products and annotation of known transcripts based on multiple sources of information. To disclose the potential of APART, we have analyzed a cDNA library derived from small ribosome-associated RNAs in Saccharomyces cerevisiae. By employing the APART pipeline, we were able to detect and confirm by independent experimental methods multiple novel stable RNA molecules differentially processed from well known ncRNAs, like rRNAs, tRNAs or snoRNAs, in a stress-dependent manner.

Radio-frequency properties of stacked long Josephson junctions with nonuniform bias current distribution

DEFF Research Database (Denmark)

Filatrella, G; Pedersen, Niels Falsig

1999-01-01

We have numerically investigated the behavior of stacks of long Josephson junctions considering a nonuniform bias profile. In the presence of a microwave field the nonuniform bias, which favors the formation of fluxons, can give rise to a change of the sequence of radio-frequency induced steps...

Modeling fuel cell stack systems

Energy Technology Data Exchange (ETDEWEB)

Lee, J H [Los Alamos National Lab., Los Alamos, NM (United States); Lalk, T R [Dept. of Mech. Eng., Texas A and M Univ., College Station, TX (United States)

1998-06-15

A technique for modeling fuel cell stacks is presented along with the results from an investigation designed to test the validity of the technique. The technique was specifically designed so that models developed using it can be used to determine the fundamental thermal-physical behavior of a fuel cell stack for any operating and design configuration. Such models would be useful tools for investigating fuel cell power system parameters. The modeling technique can be applied to any type of fuel cell stack for which performance data is available for a laboratory scale single cell. Use of the technique is demonstrated by generating sample results for a model of a Proton Exchange Membrane Fuel Cell (PEMFC) stack consisting of 125 cells each with an active area of 150 cm{sup 2}. A PEMFC stack was also used in the verification investigation. This stack consisted of four cells, each with an active area of 50 cm{sup 2}. Results from the verification investigation indicate that models developed using the technique are capable of accurately predicting fuel cell stack performance. (orig.)

Stratigraphical analysis of the neoproterozoic sedimentary sequences of the Sao Francisco Basin

International Nuclear Information System (INIS)

Martins, Mariela; Lemos, Valesca Brasil

2007-01-01

A stratigraphic analysis was performed under the principles of Sequence Stratigraphy on the neoproterozoic sedimentary sequences of the Sao Francisco Basin (Central Brazil). Three periods of deposition separated by unconformities were recognized in the Sao Francisco Megasequence: (1) Sequences 1 and 2, a cryogenian glaciogenic sequence, followed by a distal scarp carbonate ramp, developed during stable conditions, (2) Sequence 3, a Upper Cryogenian stack homoclinal ramps with mixed carbonate-siliciclastic sedimentation, deposited under a progressive influence of compressional stresses of the Brasiliano Cycle, (3) Sequence 4, a Lower Ediacaran shallow platform dominated by siliciclastic sedimentation of molassic nature, the erosion product of the nearby uplifted thrust sheets. Each of the carbonate-bearing sequences presents a distinct δ 13 C isotopic signature. The superposition to the global curve for carbon isotopic variation allowed the recognition of a major depositional hiatus between the Paranoa and Sao Francisco Megasequences, and suggested that the glacial diamictite deposition (Jequitai Formation) took place most probably around 800 Ma. This constrains the Sao Francisco Megasequence deposition to the interval between 800 and 600 Ma (the known ages of the Brasiliano Orogeny defines the upper limit). A minor depositional hiatus (700.680 Ma) was also identified separating sequences 2 and 3. Isotopic analyses suggest that from then on, more restricted environmental conditions were established in the basin, probably associated with a first order global event, which prevailed throughout deposition of the Sequence 3. (author)

Plume rise from stacks with scrubbers: a state-of-the-art review

International Nuclear Information System (INIS)

Schatzmann, M.; Policastro, A.J.

1984-01-01

The state of the art of predicting plume rise from stacks with scrubbers is evaluated critically. The significant moisture content of the scrubbed plume upon exit leads to important thermodynamic effects during plume rise that are unaccounted for in the usual dry plume rise theories. For example, under conditionally unstable atmospheres, a wet scrubbed plume treated as completely dry acts as if the atmosphere were stable, whereas in reality the scrubbed plume behaves instead as if the atmosphere were unstable. Even the use of moist plume models developed for application to cooling tower plume rise is not valid since these models 1) employ the Boussinesq approximation, 2) use a number of additional simplifying approximations that require small exit temperature differences between tower exit and ambient temperatures, and 3) are not calibrated to stack data

Stacking faults of {gamma}{prime}{prime} phase precipitated in a Ni-15Cr-8Fe-6Nb alloy; Ni-15Cr-8Fe-6Nb gokin ni sekishutsusuru {gamma}{prime}{prime} sonai no sekiso kekkan

Energy Technology Data Exchange (ETDEWEB)

Kusabiraki, K; Ikeuchi, S [Toyama University, Toyama (Japan). Faculty of Engineering

1995-09-01

The stacking faults of a metastable {gamma}{prime}{prime} phase precipitated in a nickel-base superalloy, a modified NCF 3 type alloy (X-750M) were investigated by transmission electron microscopy and X-ray diffraction method. The {gamma}{prime}{prime} precipitates are circular shaped plates at the early stage of aging and they become elliptic or irregular shaped plates at the latter stage of aging up to 1033K. Contrast which suggests the existence of stacking faults on {l_brace}112{r_brace}{sub {gamma}{prime}{prime}} planes can be seen in many of large {gamma}{prime}{prime} precipitates extracted from the specimens aged at 1033K. It is clear that the values of {gamma}{prime}{prime}/{gamma} lattice mismatch increase with increasing the aging time from the measurement of lattice constants of the {gamma} and the {gamma}{prime}{prime} phase. The formation of stacking faults on {l_brace}112{r_brace}{sub {gamma}{prime}{prime}} in the large {gamma}{prime}{prime} precipitates is due to the movement of an a/6 [111] partial dislocation introduced by {gamma}{prime}{prime} /{gamma} coherency strain. Since a part of stacking sequence has a similar crystal structure to that of a stable {delta} phase precipitates in {gamma} phase, the formation of stacking faults in the {gamma}{prime}{prime} precipitates is considered to be favorable for the stabilization of them. 14 refs., 10 figs., 1 tab.

Analysis of stacking overlap in nucleic acid structures: algorithm and application.

Science.gov (United States)

Pingali, Pavan Kumar; Halder, Sukanya; Mukherjee, Debasish; Basu, Sankar; Banerjee, Rahul; Choudhury, Devapriya; Bhattacharyya, Dhananjay

2014-08-01

RNA contains different secondary structural motifs like pseudo-helices, hairpin loops, internal loops, etc. in addition to anti-parallel double helices and random coils. The secondary structures are mainly stabilized by base-pairing and stacking interactions between the planar aromatic bases. The hydrogen bonding strength and geometries of base pairs are characterized by six intra-base pair parameters. Similarly, stacking can be represented by six local doublet parameters. These dinucleotide step parameters can describe the quality of stacking between Watson-Crick base pairs very effectively. However, it is quite difficult to understand the stacking pattern for dinucleotides consisting of non canonical base pairs from these parameters. Stacking interaction is a manifestation of the interaction between two aromatic bases or base pairs and thus can be estimated best by the overlap area between the planar aromatic moieties. We have calculated base pair overlap between two consecutive base pairs as the buried van der Waals surface between them. In general, overlap values show normal distribution for the Watson-Crick base pairs in most double helices within a range from 45 to 50 Å(2) irrespective of base sequence. The dinucleotide steps with non-canonical base pairs also are seen to have high overlap value, although their twist and few other parameters are rather unusual. We have analyzed hairpin loops of different length, bulges within double helical structures and pseudo-continuous helices using our algorithm. The overlap area analyses indicate good stacking between few looped out bases especially in GNRA tetraloop, which was difficult to quantitatively characterise from analysis of the base pair or dinucleotide step parameters. This parameter is also seen to be capable to distinguish pseudo-continuous helices from kinked helix junctions.

Environmental assessment of phosphogypsum stacks

International Nuclear Information System (INIS)

Odat, M.; Al-Attar, L.; Raja, G.; Abdul Ghany, B.

2008-03-01

Phosphogypsum is one of the most important by-products of phosphate fertilizer industry. It is kept in large stacks to the west of Homs city. Storing Phosphogypsum as open stacks exposed to various environmental effects, wind and rain, may cause pollution of the surrounding ecosystem (soil, plant, water and air). This study was carried out in order to assess the environmental impact of Phosphogypsum stacks on the surrounding ecosystem. The obtained results show that Phosphogypsum stacks did not increase the concentration of radionuclides, i.e. Radon-222 and Radium-226, the external exposed dose of gamma rays, as well as the concentration of heavy metals in the components of the ecosystem, soil, plant, water and air, as their concentrations did not exceed the permissible limits. However, the concentration of fluorine in the upper layer of soil, located to the east of the Phosphogypsum stacks, increased sufficiently, especially in the dry period of the year. Also, the concentration of fluoride in plants growing up near-by the Phosphogypsum stacks was too high, exceeded the permissible levels. This was reflected in poising plants and animals, feeding on the plants. Consequently, increasing the concentration of fluoride in soil and plants is the main impact of Phosphogypsum stacks on the surrounding ecosystem. Minimising this effect could be achieved by establishing a 50 meter wide protection zone surrounding the Phosphogypsum stacks, which has to be planted with non palatable trees, such as pine and cypress, forming wind barriers. Increasing the concentrations of heavy metals and fluoride in infiltrated water around the stacks was high; hence cautions must be taken to prevent its usage in any application or disposal in adjacent rivers and leaks.(author)

Environmental assessment of phosphogypsum stacks

International Nuclear Information System (INIS)

Odat, M.; Al-Attar, L.; Raja, G.; Abdul Ghany, B.

2009-01-01

Phosphogypsum is one of the most important by-products of phosphate fertilizer industry. It is kept in large stacks to the west of Homs city. Storing Phosphogypsum as open stacks exposed to various environmental effects, wind and rain, may cause pollution of the surrounding ecosystem (soil, plant, water and air). This study was carried out in order to assess the environmental impact of Phosphogypsum stacks on the surrounding ecosystem. The obtained results show that Phosphogypsum stacks did not increase the concentration of radionuclides, i.e. Radon-222 and Radium-226, the external exposed dose of gamma rays, as well as the concentration of heavy metals in the components of the ecosystem, soil, plant, water and air, as their concentrations did not exceed the permissible limits. However, the concentration of fluorine in the upper layer of soil, located to the east of the Phosphogypsum stacks, increased sufficiently, especially in the dry period of the year. Also, the concentration of fluoride in plants growing up near-by the Phosphogypsum stacks was too high, exceeded the permissible levels. This was reflected in poising plants and animals, feeding on the plants. Consequently, increasing the concentration of fluoride in soil and plants is the main impact of Phosphogypsum stacks on the surrounding ecosystem. Minimising this effect could be achieved by establishing a 50 meter wide protection zone surrounding the Phosphogypsum stacks, which has to be planted with non palatable trees, such as pine and cypress, forming wind barriers. Increasing the concentrations of heavy metals and fluoride in infiltrated water around the stacks was high; hence cautions must be taken to prevent its usage in any application or disposal in adjacent rivers and leaks.(author)

Mastering OpenStack

CERN Document Server

Khedher, Omar

2015-01-01

This book is intended for system administrators, cloud engineers, and system architects who want to deploy a cloud based on OpenStack in a mid- to large-sized IT infrastructure. If you have a fundamental understanding of cloud computing and OpenStack and want to expand your knowledge, then this book is an excellent checkpoint to move forward.

Solid Oxide Fuel Cell Stack Diagnostics

DEFF Research Database (Denmark)

Mosbæk, Rasmus Rode; Barfod, Rasmus Gottrup

As SOFC technology is moving closer to a commercial break through, methods to measure the “state-of-health” of operating stacks are becoming of increasing interest. This requires application of advanced methods for detailed electrical and electrochemical characterization during operation....... An operating stack is subject to compositional gradients in the gaseous reactant streams, and temperature gradients across each cell and across the stack, which complicates detailed analysis. Several experimental stacks from Topsoe Fuel Cell A/S were characterized using Electrochemical Impedance Spectroscopy...... in the hydrogen fuel gas supplied to the stack. EIS was used to examine the long-term behavior and monitor the evolution of the impedance of each of the repeating units and the whole stack. The observed impedance was analyzed in detail for one of the repeating units and the whole stack and the losses reported...

Energy hyperspace for stacking interaction in AU/AU dinucleotide step: Dispersion-corrected density functional theory study.

Science.gov (United States)

Mukherjee, Sanchita; Kailasam, Senthilkumar; Bansal, Manju; Bhattacharyya, Dhananjay

2014-01-01

Double helical structures of DNA and RNA are mostly determined by base pair stacking interactions, which give them the base sequence-directed features, such as small roll values for the purine-pyrimidine steps. Earlier attempts to characterize stacking interactions were mostly restricted to calculations on fiber diffraction geometries or optimized structure using ab initio calculations lacking variation in geometry to comment on rather unusual large roll values observed in AU/AU base pair step in crystal structures of RNA double helices. We have generated stacking energy hyperspace by modeling geometries with variations along the important degrees of freedom, roll, and slide, which were chosen via statistical analysis as maximally sequence dependent. Corresponding energy contours were constructed by several quantum chemical methods including dispersion corrections. This analysis established the most suitable methods for stacked base pair systems despite the limitation imparted by number of atom in a base pair step to employ very high level of theory. All the methods predict negative roll value and near-zero slide to be most favorable for the purine-pyrimidine steps, in agreement with Calladine's steric clash based rule. Successive base pairs in RNA are always linked by sugar-phosphate backbone with C3'-endo sugars and this demands C1'-C1' distance of about 5.4 Å along the chains. Consideration of an energy penalty term for deviation of C1'-C1' distance from the mean value, to the recent DFT-D functionals, specifically ωB97X-D appears to predict reliable energy contour for AU/AU step. Such distance-based penalty improves energy contours for the other purine-pyrimidine sequences also. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 107-120, 2014. Copyright © 2013 Wiley Periodicals, Inc.

ooi: OpenStack OCCI interface

Directory of Open Access Journals (Sweden)

Álvaro López García

2016-01-01

Full Text Available In this document we present an implementation of the Open Grid Forum’s Open Cloud Computing Interface (OCCI for OpenStack, namely ooi (Openstack occi interface, 2015  [1]. OCCI is an open standard for management tasks over cloud resources, focused on interoperability, portability and integration. ooi aims to implement this open interface for the OpenStack cloud middleware, promoting interoperability with other OCCI-enabled cloud management frameworks and infrastructures. ooi focuses on being non-invasive with a vanilla OpenStack installation, not tied to a particular OpenStack release version.

ooi: OpenStack OCCI interface

Science.gov (United States)

López García, Álvaro; Fernández del Castillo, Enol; Orviz Fernández, Pablo

In this document we present an implementation of the Open Grid Forum's Open Cloud Computing Interface (OCCI) for OpenStack, namely ooi (Openstack occi interface, 2015) [1]. OCCI is an open standard for management tasks over cloud resources, focused on interoperability, portability and integration. ooi aims to implement this open interface for the OpenStack cloud middleware, promoting interoperability with other OCCI-enabled cloud management frameworks and infrastructures. ooi focuses on being non-invasive with a vanilla OpenStack installation, not tied to a particular OpenStack release version.

Stack gas treatment

Science.gov (United States)

Reeves, Adam A.

1977-04-12

Hot stack gases transfer contained heat to a gravity flow of pebbles treated with a catalyst, cooled stacked gases and a sulfuric acid mist is withdrawn from the unit, and heat picked up by the pebbles is transferred to air for combustion or other process. The sulfuric acid (or sulfur, depending on the catalyst) is withdrawn in a recovery unit.

Post-test analysis of 20kW molten carbonate fuel cell stack operated on coal gas. Final report, August 1993--February 1996

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-05-01

A 20kW carbonate fuel cell stack was operated with coal gas for the first time in the world. The stack was tested for a total of 4,000 hours, of which 3,900 hours of testing was conducted at the Louisiana Gasification Technology Incorporated, Plaquemine, Louisiana outdoor site. The operation was on either natural gas or coal gas and switched several times without any effects, demonstrating duel fuel capabilities. This test was conducted with 9142 kJ/m{sup 3} (245 Btu/cft) coal gas provided by a slipstream from Destec`s entrained flow, slagging, slurry-fed gasifier equipped with a cold gas cleanup subsystem. The stack generated up to 21 kW with this coal gas. Following completion of this test, the stack was brought to Energy Research Corporation (ERC) and a detailed post-test analysis was conducted to identify any effects of coal gas on cell components. This investigation has shown that the direct fuel cell (DFC) can be operated with properly cleaned and humidified coal-as, providing stable performance. The basic C direct fuel cell component materials are stable and display normal stability in presence of the coal gas. No effects of the coal-borne contaminants are apparent. Further cell testing at ERC 1 17, confirmed these findings.

A Time-predictable Stack Cache

DEFF Research Database (Denmark)

Abbaspour, Sahar; Brandner, Florian; Schoeberl, Martin

2013-01-01

Real-time systems need time-predictable architectures to support static worst-case execution time (WCET) analysis. One architectural feature, the data cache, is hard to analyze when different data areas (e.g., heap allocated and stack allocated data) share the same cache. This sharing leads to le...... of a cache for stack allocated data. Our port of the LLVM C++ compiler supports the management of the stack cache. The combination of stack cache instructions and the hardware implementation of the stack cache is a further step towards timepredictable architectures.......Real-time systems need time-predictable architectures to support static worst-case execution time (WCET) analysis. One architectural feature, the data cache, is hard to analyze when different data areas (e.g., heap allocated and stack allocated data) share the same cache. This sharing leads to less...... precise results of the cache analysis part of the WCET analysis. Splitting the data cache for different data areas enables composable data cache analysis. The WCET analysis tool can analyze the accesses to these different data areas independently. In this paper we present the design and implementation...

Sedimentation stacking diagram of binary colloidal mixtures and bulk phases in the plane of chemical potentials

International Nuclear Information System (INIS)

Heras, Daniel de las; Schmidt, Matthias

2015-01-01

We give a full account of a recently proposed theory that explicitly relates the bulk phase diagram of a binary colloidal mixture to its phase stacking phenomenology under gravity (de las Heras and Schmidt 2013 Soft Matter 9 8636). As we demonstrate, the full set of possible phase stacking sequences in sedimentation-diffusion equilibrium originates from straight lines (sedimentation paths) in the chemical potential representation of the bulk phase diagram. From the analysis of various standard topologies of bulk phase diagrams, we conclude that the corresponding sedimentation stacking diagrams can be very rich, even more so when finite sample height is taken into account. We apply the theory to obtain the stacking diagram of a mixture of nonadsorbing polymers and colloids. We also present a catalog of generic phase diagrams in the plane of chemical potentials in order to facilitate the practical application of our concept, which also generalizes to multi-component mixtures. (paper)

FACIES PARTITIONING AND SEQUENCE STRATIGRAPHY OF A MIXED SILICICLASTIC-CARBONATE RAMP STACK IN THE GELASIAN OF SICILY (S ITALY: A POTENTIAL MODEL FOR ICEHOUSE, DISTALLY-STEEPENED HETEROZOAN RAMPS

Directory of Open Access Journals (Sweden)

FRANCESCO MASSARI

2012-11-01

Full Text Available The Gelasian succession of the Capodarso area (Enna-Caltanissetta basin, Sicily, Italy consists of an offlapping stack of cycles composed of siliciclastic units passing to carbonate heterozoan, clino-stratified wedges, developed from a growing positive tectonic structure. Identification of a number of facies tracts, based on sedimentary facies, biofacies and taphofacies, provided important information about the differentiation and characterisation of systems tracts and key stratal surfaces of sequence stratigraphy. The bulk of carbonate wedges are interpreted as representing the rapid falling-stage progradation of distally steepened ramps. The inferred highest rate of carbonate production during forced regressions was concomitant with active downramp resedimentation by storm-driven downwelling flows, leading to storing of most carbonate sediment on the ramp slope as clino-beds of the prograding bodies. Comparison of the Capodarso ramps with other icehouse carbonate ramps, with particular regard to the Mediterranean Plio-Pleistocene, provides clues for defining some common features. These are inferred to include: (1 brief, rapid episodes of progradation concomitant with orbitally-forced sea-level changes, resulting in limited ramp width; (2 preferential fostering of growth and downramp resedimentation of heterozoan carbonates during glacial hemicycles marked by enhanced atmospheric and marine circulation; (3 building out from positive features of entirely submerged distally-steepened ramps with storm-wave-graded profile and distinctive clinoforms; (4 ramp stacks generally consisting of mixed clastic-carbonate sequences showing an ordered spectrum of distinct frequencies; (5 rapid, continuous changes in environmental parameters, leading to the short-lived persistence of faunal communities, climax communities generally having insufficient time to form. 

Lightweight Stacks of Direct Methanol Fuel Cells

Science.gov (United States)

Narayanan, Sekharipuram; Valdez, Thomas

2004-01-01

An improved design concept for direct methanol fuel cells makes it possible to construct fuel-cell stacks that can weigh as little as one-third as much as do conventional bipolar fuel-cell stacks of equal power. The structural-support components of the improved cells and stacks can be made of relatively inexpensive plastics. Moreover, in comparison with conventional bipolar fuel-cell stacks, the improved fuel-cell stacks can be assembled, disassembled, and diagnosed for malfunctions more easily. These improvements are expected to bring portable direct methanol fuel cells and stacks closer to commercialization. In a conventional bipolar fuel-cell stack, the cells are interspersed with bipolar plates (also called biplates), which are structural components that serve to interconnect the cells and distribute the reactants (methanol and air). The cells and biplates are sandwiched between metal end plates. Usually, the stack is held together under pressure by tie rods that clamp the end plates. The bipolar stack configuration offers the advantage of very low internal electrical resistance. However, when the power output of a stack is only a few watts, the very low internal resistance of a bipolar stack is not absolutely necessary for keeping the internal power loss acceptably low.

Helping Students Design HyperCard Stacks.

Science.gov (United States)

Dunham, Ken

1995-01-01

Discusses how to teach students to design HyperCard stacks. Highlights include introducing HyperCard, developing storyboards, introducing design concepts and scripts, presenting stacks, evaluating storyboards, and continuing projects. A sidebar presents a HyperCard stack evaluation form. (AEF)

Modular fuel-cell stack assembly

Science.gov (United States)

Patel, Pinakin

2010-07-13

A fuel cell assembly having a plurality of fuel cells arranged in a stack. An end plate assembly abuts the fuel cell at an end of said stack. The end plate assembly has an inlet area adapted to receive an exhaust gas from the stack, an outlet area and a passage connecting the inlet area and outlet area and adapted to carry the exhaust gas received at the inlet area from the inlet area to the outlet area. A further end plate assembly abuts the fuel cell at a further opposing end of the stack. The further end plate assembly has a further inlet area adapted to receive a further exhaust gas from the stack, a further outlet area and a further passage connecting the further inlet area and further outlet area and adapted to carry the further exhaust gas received at the further inlet area from the further inlet area to the further outlet area.

Evaluation of field emission properties from multiple-stacked Si quantum dots

International Nuclear Information System (INIS)

Takeuchi, Daichi; Makihara, Katsunori; Ohta, Akio; Ikeda, Mitsuhisa; Miyazaki, Seiichi

2016-01-01

Multiple-stacked Si quantum dots (QDs) with ultrathin SiO 2 interlayers were formed on ultrathin SiO 2 layers by repeating a process sequence consisting of the formation of Si-QDs by low pressure chemical vapor deposition using a SiH 4 gas and the surface oxidation and subsequent surface modification by remote hydrogen and oxygen plasmas, respectively. To clarify the electron emission mechanism from multiple-stacked Si-QDs covered with an ultrathin Au top electrode, the energy distribution of the emitted electrons and its electric field dependence was measured using a hemispherical electron energy analyzer in an X-ray photoelectron spectroscopy system under DC bias application to the multiple-stacked Si-QD structure. At − 6 V and over, the energy distributions reached a peak at ~ 2.5 eV with a tail toward the higher energy side. While the electron emission intensity was increased exponentially with an increase in the applied DC bias, there was no significant increase in the emission peak energy. The observed emission characteristics can be interpreted in terms of field emissions from the second and/or third topmost Si-QDs resulting from the electric concentration there. - Highlights: • Electron field emission from 6-fold stack of Si-QDs has been evaluated. • AFM measurements show the local electron emission from individual Si-QDs. • Impact of applied bias on the electron emission energy distribution was investigated.

USPIO-enhanced 3D-cine self-gated cardiac MRI based on a stack-of-stars golden angle short echo time sequence: Application on mice with acute myocardial infarction.

Science.gov (United States)

Trotier, Aurélien J; Castets, Charles R; Lefrançois, William; Ribot, Emeline J; Franconi, Jean-Michel; Thiaudière, Eric; Miraux, Sylvain

2016-08-01

To develop and assess a 3D-cine self-gated method for cardiac imaging of murine models. A 3D stack-of-stars (SOS) short echo time (STE) sequence with a navigator echo was performed at 7T on healthy mice (n = 4) and mice with acute myocardial infarction (MI) (n = 4) injected with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles. In all, 402 spokes were acquired per stack with the incremental or the golden angle method using an angle increment of (360/402)° or 222.48°, respectively. A cylindrical k-space was filled and repeated with a maximum number of repetitions (NR) of 10. 3D cine cardiac images at 156 μm resolution were reconstructed retrospectively and compared for the two methods in terms of contrast-to-noise ratio (CNR). The golden angle images were also reconstructed with NR = 10, 6, and 3, to assess cardiac functional parameters (ejection fraction, EF) on both animal models. The combination of 3D SOS-STE and USPIO injection allowed us to optimize the identification of cardiac peaks on navigator signal and generate high CNR between blood and myocardium (15.3 ± 1.0). The golden angle method resulted in a more homogeneous distribution of the spokes inside a stack (P cine images could be obtained without electrocardiogram or respiratory gating in mice. It allows precise measurement of cardiac functional parameters even on MI mice. J. Magn. Reson. Imaging 2016;44:355-365. © 2016 Wiley Periodicals, Inc.

Guanine base stacking in G-quadruplex nucleic acids

Science.gov (United States)

Lech, Christopher Jacques; Heddi, Brahim; Phan, Anh Tuân

2013-01-01

G-quadruplexes constitute a class of nucleic acid structures defined by stacked guanine tetrads (or G-tetrads) with guanine bases from neighboring tetrads stacking with one another within the G-tetrad core. Individual G-quadruplexes can also stack with one another at their G-tetrad interface leading to higher-order structures as observed in telomeric repeat-containing DNA and RNA. In this study, we investigate how guanine base stacking influences the stability of G-quadruplexes and their stacked higher-order structures. A structural survey of the Protein Data Bank is conducted to characterize experimentally observed guanine base stacking geometries within the core of G-quadruplexes and at the interface between stacked G-quadruplex structures. We couple this survey with a systematic computational examination of stacked G-tetrad energy landscapes using quantum mechanical computations. Energy calculations of stacked G-tetrads reveal large energy differences of up to 12 kcal/mol between experimentally observed geometries at the interface of stacked G-quadruplexes. Energy landscapes are also computed using an AMBER molecular mechanics description of stacking energy and are shown to agree quite well with quantum mechanical calculated landscapes. Molecular dynamics simulations provide a structural explanation for the experimentally observed preference of parallel G-quadruplexes to stack in a 5′–5′ manner based on different accessible tetrad stacking modes at the stacking interfaces of 5′–5′ and 3′–3′ stacked G-quadruplexes. PMID:23268444

Stack filter classifiers

Energy Technology Data Exchange (ETDEWEB)

Porter, Reid B [Los Alamos National Laboratory; Hush, Don [Los Alamos National Laboratory

2009-01-01

Just as linear models generalize the sample mean and weighted average, weighted order statistic models generalize the sample median and weighted median. This analogy can be continued informally to generalized additive modeels in the case of the mean, and Stack Filters in the case of the median. Both of these model classes have been extensively studied for signal and image processing but it is surprising to find that for pattern classification, their treatment has been significantly one sided. Generalized additive models are now a major tool in pattern classification and many different learning algorithms have been developed to fit model parameters to finite data. However Stack Filters remain largely confined to signal and image processing and learning algorithms for classification are yet to be seen. This paper is a step towards Stack Filter Classifiers and it shows that the approach is interesting from both a theoretical and a practical perspective.

From the components to the stack. Developing and designing 5kW HT-PEFC stacks; Von der Komponente zum Stack. Entwicklung und Auslegung von HT-PEFC-Stacks der 5 kW-Klasse

Energy Technology Data Exchange (ETDEWEB)

Bendzulla, Anne

2010-12-22

The aim of the present project is to develop a stack design for a 5-kW HTPEFC system. First, the state of the art of potential materials and process designs will be discussed for each component. Then, using this as a basis, three potential stack designs with typical attributes will be developed and assessed in terms of practicality with the aid of a specially derived evaluation method. Two stack designs classified as promising will be discussed in detail, constructed and then characterized using short stack tests. Comparing the stack designs reveals that both designs are fundamentally suitable for application in a HT-PEFC system with on-board supply. However, some of the performance data differ significantly for the two stack designs. The preferred stack design for application in a HT-PEFC system is characterized by robust operating behaviour and reproducible high-level performance data. Moreover, in compact constructions (120 W/l at 60 W/kg), the stack design allows flexible cooling with thermal oil or air, which can be adapted to suit specific applications. Furthermore, a defined temperature gradient can be set during operation, allowing the CO tolerance to be increased by up to 10 mV. The short stack design developed within the scope of the present work therefore represents an ideal basis for developing a 5-kW HT-PEFC system. Topics for further research activities include improving the performance by reducing weight and/or volume, as well as optimizing the heat management. The results achieved within the framework of this work clearly show that HTPEFC stacks have the potential to play a decisive role in increasing efficiency in the future, particularly when combined with an on-board supply system. (orig.) [German] Ziel der vorliegenden Arbeit ist die Entwicklung eines Stackkonzeptes fuer ein 5 kW-HT-PEFC System. Dazu wird zunaechst fuer jede Komponente der Stand der Technik moeglicher Materialien und Prozesskonzepte diskutiert. Darauf aufbauend werden drei

Cooling Performance Characteristics of the Stack Thermal Management System for Fuel Cell Electric Vehicles under Actual Driving Conditions

Directory of Open Access Journals (Sweden)

Ho-Seong Lee

2016-04-01

Full Text Available The cooling performance of the stack radiator of a fuel cell electric vehicle was evaluated under various actual road driving conditions, such as highway and uphill travel. The thermal stability was then optimized, thereby ensuring stable operation of the stack thermal management system. The coolant inlet temperature of the radiator in the highway mode was lower than that associated with the uphill mode because the corresponding frontal air velocity was higher than obtained in the uphill mode. In both the highway and uphill modes, the coolant temperatures of the radiator, operated under actual road driving conditions, were lower than the allowable limit (80 °C; this is the maximum temperature at which stable operation of the stack thermal management system of the fuel cell electric vehicle could be maintained. Furthermore, under actual road driving conditions in uphill mode, the initial temperature difference (ITD between the coolant temperature and air temperature of the system was higher than that associated with the highway mode; this higher ITD occurred even though the thermal load of the system in uphill mode was greater than that corresponding to the highway mode. Since the coolant inlet temperature is expected to exceed the allowable limit (80 °C in uphill mode under higher ambient temperature with air conditioning system operation, the FEM design layout should be modified to improve the heat capacity. In addition, the overall volume of the stack cooling radiator is 52.2% higher than that of the present model and the coolant inlet temperature of the improved radiator is 22.7% lower than that of the present model.

Text-Filled Stacked Area Graphs

DEFF Research Database (Denmark)

Kraus, Martin

2011-01-01

-filled stacked area graphs; i.e., graphs that feature stacked areas that are filled with small-typed text. Since these graphs allow for computing the text layout automatically, it is possible to include large amounts of textual detail with very little effort. We discuss the most important challenges and some...... solutions for the design of text-filled stacked area graphs with the help of an exemplary visualization of the genres, publication years, and titles of a database of several thousand PC games....

Formation of long-period stacking ordered structures in Mg88M5Y7 (M = Ti, Ni and Pb) casting alloys

International Nuclear Information System (INIS)

Jin, Qian-Qian; Fang, Can-Feng; Mi, Shao-Bo

2013-01-01

Highlights: •Apart from 18R-LPSO, 14H-LPSO structure was determined in the Mg-Ni-Y alloys. •The appearance of twin-related structure in 18R-LPSO structure results from the stacking faults in the stacking sequence of the closely packed planes. •A new (Pb, Mg) 2 Y phase with a body-centered orthorhombic structure was determined in the Mg-Pb-Y alloy. •No LPSO structures were found in the Mg-Pb-Y and Mg-Ti-Y casting alloys. -- Abstract: Formation of long-period stacking ordered (LPSO) structures is investigated in Mg 88 M 5 Y 7 (M = Ti, Ni and Pb) casting alloys by means of electron microscopy and X-ray diffraction. In the Mg 88 Ni 5 Y 7 casting alloy, 14H-LPSO structure is observed in a small amount, which coexists with 18R-LPSO structure. The appearance of stacking faults in 18R-LPSO structure results in twin-related structure in the stacking sequence of the closely packed planes. A new (Pb, Mg) 2 Y phase with a body-centered orthorhombic structure is determined in the Mg 88 Pb 5 Y 7 alloy. No LPSO structures are found in the Mg 88 Pb 5 Y 7 and Mg 88 Ti 5 Y 7 casting alloys. In terms of the atomic radius and heat of mixing, the formation ability of LPSO structure in the present alloys is discussed

Van der Waals stacks of few-layer h-AlN with graphene: an ab initio study of structural, interaction and electronic properties

International Nuclear Information System (INIS)

Dos Santos, Renato B; Mota, F de Brito; Rivelino, R; Kakanakova-Georgieva, A; Gueorguiev, G K

2016-01-01

Graphite-like hexagonal AlN (h-AlN) multilayers have been experimentally manifested and theoretically modeled. The development of any functional electronics applications of h-AlN would most certainly require its integration with other layered materials, particularly graphene. Here, by employing vdW-corrected density functional theory calculations, we investigate structure, interaction energy, and electronic properties of van der Waals stacking sequences of few-layer h-AlN with graphene. We find that the presence of a template such as graphene induces enough interlayer charge separation in h-AlN, favoring a graphite-like stacking formation. We also find that the interface dipole, calculated per unit cell of the stacks, tends to increase with the number of stacked layers of h-AlN and graphene. (paper)

Influence of Layup Sequence on the Surface Accuracy of Carbon Fiber Composite Space Mirrors

Science.gov (United States)

Yang, Zhiyong; Liu, Qingnian; Zhang, Boming; Xu, Liang; Tang, Zhanwen; Xie, Yongjie

2018-04-01

Layup sequence is directly related to stiffness and deformation resistance of the composite space mirror, and error caused by layup sequence can affect the surface precision of composite mirrors evidently. Variation of layup sequence with the same total thickness of composite space mirror changes surface form of the composite mirror, which is the focus of our study. In our research, the influence of varied quasi-isotropic stacking sequences and random angular deviation on the surface accuracy of composite space mirrors was investigated through finite element analyses (FEA). We established a simulation model for the studied concave mirror with 500 mm diameter, essential factors of layup sequences and random angular deviations on different plies were discussed. Five guiding findings were described in this study. Increasing total plies, optimizing stacking sequence and keeping consistency of ply alignment in ply placement are effective to improve surface accuracy of composite mirror.

Stable structures of Al510–800 clusters and lowest energy sequence of truncated octahedral Al clusters up to 10,000 atoms

International Nuclear Information System (INIS)

Wu, Xia; He, Chengdong

2012-01-01

Highlights: ► The stable structures of Al 510–800 clusters are obtained with the NP-B potential. ► Al 510–800 clusters adopt truncated octahedral (TO) growth pattern based on complete TOs at Al 405 , Al 586 , and Al 711 . ► The lowest energy sequence of complete TOs up to the size 10,000 is proposed. -- Abstract: The stable structures of Al 510–800 clusters are obtained using dynamic lattice searching with constructed cores (DLSc) method by the NP-B potential. According to the structural growth rule, octahedra and truncated octahedra (TO) configurations are adopted as the inner cores in DLSc method. The results show that in the optimized structures two complete TO structures are found at Al 586 and Al 711 . Furthermore, Al 510–800 clusters adopt TO growth pattern on complete TOs at Al 405 , Al 586 , and Al 711 , and the configurations of the surface atoms are investigated. On the other hand, Al clusters with complete TO motifs are studied up to the size 10,000 by the geometrical construction method. The structural characteristics of complete TOs are denoted by the term “family”, and the growth sequence of Al clusters is investigated. The lowest energy sequence of complete TOs is proposed.

V-stack piezoelectric actuator

Science.gov (United States)

Ardelean, Emil V.; Clark, Robert L.

2001-07-01

Aeroelastic control of wings by means of a distributed, trailing-edge control surface is of interest with regards to maneuvers, gust alleviation, and flutter suppression. The use of high energy density, piezoelectric materials as motors provides an appealing solution to this problem. A comparative analysis of the state of the art actuators is currently being conducted. A new piezoelectric actuator design is presented. This actuator meets the requirements for trailing edge flap actuation in both stroke and force. It is compact, simple, sturdy, and leverages stroke geometrically with minimum force penalties while displaying linearity over a wide range of stroke. The V-Stack Piezoelectric Actuator, consists of a base, a lever, two piezoelectric stacks, and a pre-tensioning element. The work is performed alternately by the two stacks, placed on both sides of the lever. Pre-tensioning can be readily applied using a torque wrench, obviating the need for elastic elements and this is for the benefit of the stiffness of the actuator. The characteristics of the actuator are easily modified by changing the base or the stacks. A prototype was constructed and tested experimentally to validate the theoretical model.

Reflector imaging by diffraction stacking with stacking velocity analysis; Jugo sokudo kaiseki wo tomonau sanran jugoho ni yoru hanshamen imaging

Energy Technology Data Exchange (ETDEWEB)

Matsushima, J; Rokugawa, S; Kato, Y [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Yokota, T [Japan National Oil Corp., Tokyo (Japan); Miyazaki, T [Geological Survey of Japan, Tsukuba (Japan)

1997-10-22

Concerning seismic reflection survey for geometrical arrangement between pits, the scattering stacking method with stacking velocity analysis is compared with the CDP (common depth point horizontal stacking method). The advantages of the CDP supposedly include the following. Since it presumes an average velocity field, it can determine velocities having stacking effects. The method presumes stratification and, since such enables the division of huge quantities of observed data into smaller groups, more data can be calculated in a shorter time period. The method has disadvantages, attributable to its presuming an average velocity field, that accuracy in processing is lower when the velocity field contrast is higher, that accuracy in processing is low unless stratification is employed, and that velocities obtained from stacking velocity analysis are affected by dipped structures. Such shortcomings may be remedied in the scattering stacking method with stacking velocity analysis. Possibilities are that, as far as the horizontal reflection plane is concerned, it may yield stack records higher in S/N ratio than the CDP. Findings relative to dipped reflection planes will be introduced at the presentation. 6 refs., 12 figs.

Towards stacked zone plates

International Nuclear Information System (INIS)

Werner, S; Rehbein, S; Guttman, P; Heim, S; Schneider, G

2009-01-01

Fresnel zone plates are the key optical elements for soft and hard x-ray microscopy. For short exposure times and minimum radiation load of the specimen the diffraction efficiency of the zone plate objectives has to be maximized. As the efficiency strongly depends on the height of the diffracting zone structures the achievable aspect ratio of the nanostructures determines these limits. To reach aspect ratios ≥ 20:1 for high efficient optics we propose to superimpose zone plates on top of each other. With this multiplication approach the final aspect ratio is only limited by the number of stacked zone plate layers. For the stack process several nanostructuring process steps have to be developed and/or improved. Our results show for the first time two layers of zone plates stacked on top of each other.

Durable solid oxide electrolysis cells and stacks

Energy Technology Data Exchange (ETDEWEB)

Ming Chen

2010-08-15

The purpose of this project was to make a substantial contribution to development of a cost competitive electrolysis technology based on solid oxide cells. The strategy was to address what had been identified as the key issues in previous research projects. Accordingly five lines of work were carried out in the here reported project: 1) Cell and stack element testing and post test characterization to identify major degradation mechanisms under electrolysis operation. 2) Development of interconnects and coatings to allow stable electrolysis operation at approx850 deg. C or above. 3) Development of seals with reduced Si emission. 4) Development of durable SOEC cathodes. 5) Modeling. Good progress has been made on several of the planned activities. The outcome and most important achievements of the current project are listed for the five lines of the work. (LN)

Tunable electro-optic filter stack

Science.gov (United States)

Fontecchio, Adam K.; Shriyan, Sameet K.; Bellingham, Alyssa

2017-09-05

A holographic polymer dispersed liquid crystal (HPDLC) tunable filter exhibits switching times of no more than 20 microseconds. The HPDLC tunable filter can be utilized in a variety of applications. An HPDLC tunable filter stack can be utilized in a hyperspectral imaging system capable of spectrally multiplexing hyperspectral imaging data acquired while the hyperspectral imaging system is airborne. HPDLC tunable filter stacks can be utilized in high speed switchable optical shielding systems, for example as a coating for a visor or an aircraft canopy. These HPDLC tunable filter stacks can be fabricated using a spin coating apparatus and associated fabrication methods.

Anisotropic formation and distribution of stacking faults in II-VI semiconductor nanorods.

Science.gov (United States)

Hughes, Steven M; Alivisatos, A Paul

2013-01-09

Nanocrystals of cadmium selenide exhibit a form of polytypism with stable forms in both the wurtzite and zinc blende crystal structures. As a result, wurtzite nanorods of cadmium selenide tend to form stacking faults of zinc blende along the c-axis. These faults were found to preferentially form during the growth of the (001) face, which accounts for 40% of the rod's total length. Since II-VI semiconductor nanorods lack inversion symmetry along the c-axis of the particle, the two ends of the nanorod may be identified by this anisotropic distribution of faults.

Correlation and Stacking of Relative Paleointensity and Oxygen Isotope Data

Science.gov (United States)

Lurcock, P. C.; Channell, J. E.; Lee, D.

2012-12-01

The transformation of a depth-series into a time-series is routinely implemented in the geological sciences. This transformation often involves correlation of a depth-series to an astronomically calibrated time-series. Eyeball tie-points with linear interpolation are still regularly used, although these have the disadvantages of being non-repeatable and not based on firm correlation criteria. Two automated correlation methods are compared: the simulated annealing algorithm (Huybers and Wunsch, 2004) and the Match protocol (Lisiecki and Lisiecki, 2002). Simulated annealing seeks to minimize energy (cross-correlation) as "temperature" is slowly decreased. The Match protocol divides records into intervals, applies penalty functions that constrain accumulation rates, and minimizes the sum of the squares of the differences between two series while maintaining the data sequence in each series. Paired relative paleointensity (RPI) and oxygen isotope records, such as those from IODP Site U1308 and/or reference stacks such as LR04 and PISO, are warped using known warping functions, and then the un-warped and warped time-series are correlated to evaluate the efficiency of the correlation methods. Correlations are performed in tandem to simultaneously optimize RPI and oxygen isotope data. Noise spectra are introduced at differing levels to determine correlation efficiency as noise levels change. A third potential method, known as dynamic time warping, involves minimizing the sum of distances between correlated point pairs across the whole series. A "cost matrix" between the two series is analyzed to find a least-cost path through the matrix. This least-cost path is used to nonlinearly map the time/depth of one record onto the depth/time of another. Dynamic time warping can be expanded to more than two dimensions and used to stack multiple time-series. This procedure can improve on arithmetic stacks, which often lose coherent high-frequency content during the stacking process.

Forced Air-Breathing PEMFC Stacks

Directory of Open Access Journals (Sweden)

K. S. Dhathathreyan

2012-01-01

Full Text Available Air-breathing fuel cells have a great potential as power sources for various electronic devices. They differ from conventional fuel cells in which the cells take up oxygen from ambient air by active or passive methods. The air flow occurs through the channels due to concentration and temperature gradient between the cell and the ambient conditions. However developing a stack is very difficult as the individual cell performance may not be uniform. In order to make such a system more realistic, an open-cathode forced air-breathing stacks were developed by making appropriate channel dimensions for the air flow for uniform performance in a stack. At CFCT-ARCI (Centre for Fuel Cell Technology-ARC International we have developed forced air-breathing fuel cell stacks with varying capacity ranging from 50 watts to 1500 watts. The performance of the stack was analysed based on the air flow, humidity, stability, and so forth, The major advantage of the system is the reduced number of bipolar plates and thereby reduction in volume and weight. However, the thermal management is a challenge due to the non-availability of sufficient air flow to remove the heat from the system during continuous operation. These results will be discussed in this paper.

Method for monitoring stack gases for uranium activity

International Nuclear Information System (INIS)

Beverly, C.R.; Ernstberger, H.G.

1988-01-01

A method for sampling stack gases emanating from the purge cascade of a gaseous diffusion cascade system utilized to enrich uranium for determining the presence and extent of uranium in the stack gases in the form of gaseous uranium hexafluoride, is described comprising the steps of removing a side stream of gases from the stack gases, contacting the side stream of the stack gases with a stream of air sufficiently saturated with moisture for reacting with and converting any gaseous uranium hexafluroide contracted thereby in the side stream of stack gases to particulate uranyl fluoride. Thereafter contacting the side stream of stack gases containing the particulate uranyl fluoride with moving filter means for continuously intercepting and conveying the intercepted particulate uranyl fluoride away from the side stream of stack gases, and continually scanning the moving filter means with radiation monitoring means for sensing the presence and extent of particulate uranyl fluoride on the moving filter means which is indicative of the extent of particulate uranyl fluoride in the side stream of stack gases which in turn is indicative of the presence and extent of uranium hexafluoride in the stack gases

Flexural characteristics of a stack leg

International Nuclear Information System (INIS)

Cook, J.

1979-06-01

A 30 MV tandem Van de Graaff accelerator is at present under construction at Daresbury Laboratory. The insulating stack of the machine is of modular construction, each module being 860 mm in length. Each live section stack module contains 8 insulating legs mounted between bulkhead rings. The design, fabrication (from glass discs bonded to stainless steel discs using an epoxy film adhesive) and testing of the stack legs is described. (U.K.)

Evaluation of flow fields on bubble removal and system performance in an ammonium bicarbonate reverse electrodialysis stack

KAUST Repository

Hatzell, Marta C.

2013-11-01

Ammonium bicarbonate has recently been demonstrated to be an excellent thermolytic solution for energy generation in reverse electrodialysis (RED) stacks. However, operating RED stacks at room temperatures can promote gaseous bubble (CO2, NH3) accumulation within the stack, reducing overall system performance. The management and minimization of bubbles formed in RED flow fields is an important operational issue which has yet to be addressed. Flow fields with and without spacers in RED stacks were analyzed to determine how both fluid flow and the buildup and removal of bubbles affected performance. In the presence of a spacer, the membrane resistance increased by ~50Ω, resulting in a decrease in power density by 30% from 0.140Wm-2 to 0.093Wm-2. Shorter channels reduced concentration polarization affects, and resulted in 3-23% higher limiting current density. Gas accumulation was minimized through the use of short vertically aligned channels, and consequently the amount of the membrane area covered by bubbles was reduced from ~20% to 7% which caused a 12% increase in power density. As ammonium bicarbonate RED systems are scaled up, attention to channel aspect ratio, length, and alignment will enable more stable performance. © 2013 Elsevier B.V.

Time-predictable Stack Caching

DEFF Research Database (Denmark)

Abbaspourseyedi, Sahar

completely. Thus, in systems with hard deadlines the worst-case execution time (WCET) of the real-time software running on them needs to be bounded. Modern architectures use features such as pipelining and caches for improving the average performance. These features, however, make the WCET analysis more...... addresses, provides an opportunity to predict and tighten the WCET of accesses to data in caches. In this thesis, we introduce the time-predictable stack cache design and implementation within a time-predictable processor. We introduce several optimizations to our design for tightening the WCET while...... keeping the timepredictability of the design intact. Moreover, we provide a solution for reducing the cost of context switching in a system using the stack cache. In design of these caches, we use custom hardware and compiler support for delivering time-predictable stack data accesses. Furthermore...

Principles for Instructional Stack Development in HyperCard.

Science.gov (United States)

McEneaney, John E.

The purpose of this paper is to provide information about obtaining and using HyperCard stacks that introduce users to principles of stack development. The HyperCard stacks described are available for downloading free of charge from a server at Indiana University South Bend. Specific directions are given for stack use, with advice for beginners. A…

DBaaS with OpenStack Trove

CERN Document Server

Giardini, Andrea

2013-01-01

The purpose of the project was to evaluate the Trove component for OpenStack, understand if it can be used with the CERN infrastructure and report the benefits and disadvantages of this software. Currently, databases for CERN projects are provided by a DbaaS software developed inside the IT-DB group. This solution works well with the actual infrastructure but it is not easy to maintain. With the migration of the CERN infrastructure to OpenStack the Database group started to evaluate the Trove component. Instead of mantaining an own DbaaS service it can be interesting to migrate everything to OpenStack and replace the actual DbaaS software with Trove. This way both virtual machines and databases will be managed by OpenStack itself.

Uranium chemistry in stack solutions and leachates of phosphogypsum disposed at a coastal area in Cyprus.

Science.gov (United States)

Lysandrou, M; Pashalidis, I

2008-02-01

The effect of the matrix composition (main constituents) on the concentration and chemical behavior of uranium in phosphogypsum stack solutions and leachates has been investigated. Solid and aqueous samples were taken from three different sub-areas of a phosphogypsum stack at a coastal area in Vasilikos (Cyprus). The sub-areas are characterized whether by their acidity (e.g. "aged" and "non-aged" phosphogypsum) or by their salt content, originating from pulping water during wet stacking or (after deposition) from the adjacent sea. Measurements in stack solutions and leachates showed that phosphogypsum characteristics affect both, the concentration and the chemical behavior of uranium in solution. Uranium concentration in solutions of increased salinity is up to three orders of magnitude higher than in solutions of low salinity and this is attributed to the effect of ionic strength on the solubility of phosphogypsum. Modelling showed that uranium in stack solutions is predominantly present in the form of uranium(VI) phosphate complexes (e.g. UO(2)(H(2)PO(4))(2), UO(2)HPO(4)), whereas in leachates uranium(VI) fluoro complexes (e.g. UO(2)F(2), UO(2)F(3)(-)) are predominant in solution. The latter indicates that elution of uranium from phosphogypsum takes places most probably in the form of fluoro complexes. Both, effective elution by saline water and direct migration of uranium to the sea, where it forms very stable uranium(VI) carbonato complexes, indicate that the adjacent sea will be the final receptor of uranium released from Vasilikos phosphogypsum.

Stacking the Equiangular Spiral

OpenAIRE

Agrawal, A.; Azabi, Y. O.; Rahman, B. M.

2013-01-01

We present an algorithm that adapts the mature Stack and Draw (SaD) methodology for fabricating the exotic Equiangular Spiral Photonic Crystal Fiber. (ES-PCF) The principle of Steiner chains and circle packing is exploited to obtain a non-hexagonal design using a stacking procedure based on Hexagonal Close Packing. The optical properties of the proposed structure are promising for SuperContinuum Generation. This approach could make accessible not only the equiangular spiral but also other qua...

Stochastic stacking without filters

International Nuclear Information System (INIS)

Johnson, R.P.; Marriner, J.

1982-12-01

The rate of accumulation of antiprotons is a critical factor in the design of p anti p colliders. A design of a system to accumulate higher anti p fluxes is presented here which is an alternative to the schemes used at the CERN AA and in the Fermilab Tevatron I design. Contrary to these stacking schemes, which use a system of notch filters to protect the dense core of antiprotons from the high power of the stack tail stochastic cooling, an eddy current shutter is used to protect the core in the region of the stack tail cooling kicker. Without filters one can have larger cooling bandwidths, better mixing for stochastic cooling, and easier operational criteria for the power amplifiers. In the case considered here a flux of 1.4 x 10 8 per sec is achieved with a 4 to 8 GHz bandwidth

Assessing Elementary Algebra with STACK

Science.gov (United States)

Sangwin, Christopher J.

2007-01-01

This paper concerns computer aided assessment (CAA) of mathematics in which a computer algebra system (CAS) is used to help assess students' responses to elementary algebra questions. Using a methodology of documentary analysis, we examine what is taught in elementary algebra. The STACK CAA system, http://www.stack.bham.ac.uk/, which uses the CAS…

Learning OpenStack networking (Neutron)

CERN Document Server

Denton, James

2014-01-01

If you are an OpenStack-based cloud operator with experience in OpenStack Compute and nova-network but are new to Neutron networking, then this book is for you. Some networking experience is recommended, and a physical network infrastructure is required to provide connectivity to instances and other network resources configured in the book.

Consolidity: Stack-based systems change pathway theory elaborated

Directory of Open Access Journals (Sweden)

Hassen Taher Dorrah

2014-06-01

Full Text Available This paper presents an elaborated analysis for investigating the stack-based layering processes during the systems change pathway. The system change pathway is defined as the path resulting from the combinations of all successive changes induced on the system when subjected to varying environments, activities, events, or any excessive internal or external influences and happenings “on and above” its normal stands, situations or set-points during its course of life. The analysis is essentially based on the important overall system paradigm of “Time driven-event driven-parameters change”. Based on this paradigm, it is considered that any affected activity, event or varying environment is intelligently self-recorded inside the system through an incremental consolidity-scaled change in system parameters of the stack-based layering types. Various joint stack-based mathematical and graphical approaches supported by representable case studies are suggested for the identification, extraction, and processing of various stack-based systems changes layering of different classifications and categorizations. Moreover, some selected real life illustrative applications are provided to demonstrate the (infinite stack-based identification and recognition of the change pathway process in the areas of geology, archeology, life sciences, ecology, environmental science, engineering, materials, medicine, biology, sociology, humanities, and other important fields. These case studies and selected applications revealed that there are general similarities of the stack-based layering structures and formations among all the various research fields. Such general similarities clearly demonstrate the global concept of the “fractals-general stacking behavior” of real life systems during their change pathways. Therefore, it is recommended that concentrated efforts should be expedited toward building generic modular stack-based systems or blocks for the mathematical

Glassy carbon based supercapacitor stacks

Energy Technology Data Exchange (ETDEWEB)

Baertsch, M; Braun, A; Koetz, R; Haas, O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

Considerable effort is being made to develop electrochemical double layer capacitors (EDLC) that store relatively large quantities of electrical energy and possess at the same time a high power density. Our previous work has shown that glassy carbon is suitable as a material for capacitor electrodes concerning low resistance and high capacity requirements. We present the development of bipolar electrochemical glassy carbon capacitor stacks of up to 3 V. Bipolar stacks are an efficient way to meet the high voltage and high power density requirements for traction applications. Impedance and cyclic voltammogram measurements are reported here and show the frequency response of a 1, 2, and 3 V stack. (author) 3 figs., 1 ref..

Actuators Using Piezoelectric Stacks and Displacement Enhancers

Science.gov (United States)

Bar-Cohen, Yoseph; Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Lee, Hyeong Jae; Walkenmeyer, Phillip; Lih, Shyh-Shiuh

2015-01-01

Actuators are used to drive all active mechanisms including machines, robots, and manipulators to name a few. The actuators are responsible for moving, manipulating, displacing, pushing and executing any action that is needed by the mechanism. There are many types and principles of actuation that are responsible for these movements ranging from electromagnetic, electroactive, thermo-mechanic, piezoelectric, electrostrictive etc. Actuators are readily available from commercial producers but there is a great need for reducing their size, increasing their efficiency and reducing their weight. Studies at JPL’s Non Destructive Evaluation and Advanced Actuators (NDEAA) Laboratory have been focused on the use of piezoelectric stacks and novel designs taking advantage of piezoelectric’s potential to provide high torque/force density actuation and high electromechanical conversion efficiency. The actuators/motors that have been developed and reviewed in this paper are operated by various horn configurations as well as the use of pre-stress flexures that make them thermally stable and increases their coupling efficiency. The use of monolithic designs that pre-stress the piezoelectric stack eliminates the use of compression stress bolt. These designs enable the embedding of developed solid-state motors/actuators in any structure with the only macroscopically moving parts are the rotor or the linear translator. Finite element modeling and design tools were used to determine the requirements and operation parameters and the results were used to simulate, design and fabricate novel actuators/motors. The developed actuators and performance will be described and discussed in this paper.

Status of MCFC stack technology at IHI

Energy Technology Data Exchange (ETDEWEB)

Hosaka, M.; Morita, T.; Matsuyama, T.; Otsubo, M. [Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo (Japan)

1996-12-31

The molten carbonate fuel cell (MCFC) is a promising option for highly efficient power generation possible to enlarge. IHI has been studying parallel flow MCFC stacks with internal manifolds that have a large electrode area of 1m{sup 2}. IHI will make two 250 kW stacks for MW plant, and has begun to make cell components for the plant. To improve the stability of stack, soft corrugated plate used in the separator has been developed, and a way of gathering current from stacks has been studied. The DC output potential of the plant being very high, the design of electric insulation will be very important. A 20 kW short stack test was conducted in 1995 FY to certificate some of the improvements and components of the MW plant. These activities are presented below.

Spherical Torus Center Stack Design

International Nuclear Information System (INIS)

C. Neumeyer; P. Heitzenroeder; C. Kessel; M. Ono; M. Peng; J. Schmidt; R. Woolley; I. Zatz

2002-01-01

The low aspect ratio spherical torus (ST) configuration requires that the center stack design be optimized within a limited available space, using materials within their established allowables. This paper presents center stack design methods developed by the National Spherical Torus Experiment (NSTX) Project Team during the initial design of NSTX, and more recently for studies of a possible next-step ST (NSST) device

The untyped stack calculus and Bohm's theorem

Directory of Open Access Journals (Sweden)

Alberto Carraro

2013-03-01

Full Text Available The stack calculus is a functional language in which is in a Curry-Howard correspondence with classical logic. It enjoys confluence but, as well as Parigot's lambda-mu, does not admit the Bohm Theorem, typical of the lambda-calculus. We present a simple extension of stack calculus which is for the stack calculus what Saurin's Lambda-mu is for lambda-mu.

Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems

Science.gov (United States)

Su, Ji; Jiang, Xiaoning; Zu, Tian-Bing

2011-01-01

The Stacked HYBATS (Hybrid Actuation/Transduction system) demonstrates significantly enhanced electromechanical performance by using the cooperative contributions of the electromechanical responses of multilayer, stacked negative strain components and positive strain components. Both experimental and theoretical studies indicate that, for Stacked HYBATS, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The coupled resonance mode between positive strain and negative strain components of Stacked HYBATS is much stronger than the resonance of a single element actuation only when the effective lengths of the two kinds of elements match each other. Compared with the previously invented hybrid actuation system (HYBAS), the multilayer Stacked HYBATS can be designed to provide high mechanical load capability, low voltage driving, and a highly effective piezoelectric constant. The negative strain component will contract, and the positive strain component will expand in the length directions when an electric field is applied on the device. The interaction between the two elements makes an enhanced motion along the Z direction for Stacked-HYBATS. In order to dominate the dynamic length of Stacked-HYBATS by the negative strain component, the area of the cross-section for the negative strain component will be much larger than the total cross-section areas of the two positive strain components. The transverse strain is negative and longitudinal strain positive in inorganic materials, such as ceramics/single crystals. Different piezoelectric multilayer stack configurations can make a piezoelectric ceramic/single-crystal multilayer stack exhibit negative strain or positive strain at a certain direction without increasing the applied voltage. The difference of this innovation from the HYBAS is that all the elements can be made from one-of-a-kind materials. Stacked HYBATS can provide an extremely effective piezoelectric

Simple Stacking Methods for Silicon Micro Fuel Cells

Directory of Open Access Journals (Sweden)

Gianmario Scotti

2014-08-01

Full Text Available We present two simple methods, with parallel and serial gas flows, for the stacking of microfabricated silicon fuel cells with integrated current collectors, flow fields and gas diffusion layers. The gas diffusion layer is implemented using black silicon. In the two stacking methods proposed in this work, the fluidic apertures and gas flow topology are rotationally symmetric and enable us to stack fuel cells without an increase in the number of electrical or fluidic ports or interconnects. Thanks to this simplicity and the structural compactness of each cell, the obtained stacks are very thin (~1.6 mm for a two-cell stack. We have fabricated two-cell stacks with two different gas flow topologies and obtained an open-circuit voltage (OCV of 1.6 V and a power density of 63 mW·cm−2, proving the viability of the design.

Open stack thermal battery tests

Energy Technology Data Exchange (ETDEWEB)

Long, Kevin N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Christine C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grillet, Anne M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Headley, Alexander J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fenton, Kyle [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wong, Dennis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ingersoll, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-04-17

We present selected results from a series of Open Stack thermal battery tests performed in FY14 and FY15 and discuss our findings. These tests were meant to provide validation data for the comprehensive thermal battery simulation tools currently under development in Sierra/Aria under known conditions compared with as-manufactured batteries. We are able to satisfy this original objective in the present study for some test conditions. Measurements from each test include: nominal stack pressure (axial stress) vs. time in the cold state and during battery ignition, battery voltage vs. time against a prescribed current draw with periodic pulses, and images transverse to the battery axis from which cell displacements are computed. Six battery configurations were evaluated: 3, 5, and 10 cell stacks sandwiched between 4 layers of the materials used for axial thermal insulation, either Fiberfrax Board or MinK. In addition to the results from 3, 5, and 10 cell stacks with either in-line Fiberfrax Board or MinK insulation, a series of cell-free “control” tests were performed that show the inherent settling and stress relaxation based on the interaction between the insulation and heat pellets alone.

Adding large EM stack support

KAUST Repository

Holst, Glendon

2016-12-01

Serial section electron microscopy (SSEM) image stacks generated using high throughput microscopy techniques are an integral tool for investigating brain connectivity and cell morphology. FIB or 3View scanning electron microscopes easily generate gigabytes of data. In order to produce analyzable 3D dataset from the imaged volumes, efficient and reliable image segmentation is crucial. Classical manual approaches to segmentation are time consuming and labour intensive. Semiautomatic seeded watershed segmentation algorithms, such as those implemented by ilastik image processing software, are a very powerful alternative, substantially speeding up segmentation times. We have used ilastik effectively for small EM stacks – on a laptop, no less; however, ilastik was unable to carve the large EM stacks we needed to segment because its memory requirements grew too large – even for the biggest workstations we had available. For this reason, we refactored the carving module of ilastik to scale it up to large EM stacks on large workstations, and tested its efficiency. We modified the carving module, building on existing blockwise processing functionality to process data in manageable chunks that can fit within RAM (main memory). We review this refactoring work, highlighting the software architecture, design choices, modifications, and issues encountered.

Laser pulse stacking method

Science.gov (United States)

Moses, E.I.

1992-12-01

A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.

The impact of base stacking on the conformations and electrostatics of single-stranded DNA.

Science.gov (United States)

Plumridge, Alex; Meisburger, Steve P; Andresen, Kurt; Pollack, Lois

2017-04-20

Single-stranded DNA (ssDNA) is notable for its interactions with ssDNA binding proteins (SSBs) during fundamentally important biological processes including DNA repair and replication. Previous work has begun to characterize the conformational and electrostatic properties of ssDNA in association with SSBs. However, the conformational distributions of free ssDNA have been difficult to determine. To capture the vast array of ssDNA conformations in solution, we pair small angle X-ray scattering with novel ensemble fitting methods, obtaining key parameters such as the size, shape and stacking character of strands with different sequences. Complementary ion counting measurements using inductively coupled plasma atomic emission spectroscopy are employed to determine the composition of the ion atmosphere at physiological ionic strength. Applying this combined approach to poly dA and poly dT, we find that the global properties of these sequences are very similar, despite having vastly different propensities for single-stranded helical stacking. These results suggest that a relatively simple mechanism for the binding of ssDNA to non-specific SSBs may be at play, which explains the disparity in binding affinities observed for these systems. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Levitation characteristics of HTS tape stacks

Energy Technology Data Exchange (ETDEWEB)

Pokrovskiy, S. V.; Ermolaev, Y. S.; Rudnev, I. A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation)

2015-03-15

Due to the considerable development of the technology of second generation high-temperature superconductors and a significant improvement in their mechanical and transport properties in the last few years it is possible to use HTS tapes in the magnetic levitation systems. The advantages of tapes on a metal substrate as compared with bulk YBCO material primarily in the strength, and the possibility of optimizing the convenience of manufacturing elements of levitation systems. In the present report presents the results of the magnetic levitation force measurements between the stack of HTS tapes containing of tapes and NdFeB permanent magnet in the FC and ZFC regimes. It was found a non- linear dependence of the levitation force from the height of the array of stack in both modes: linear growth at small thickness gives way to flattening and constant at large number of tapes in the stack. Established that the levitation force of stacks comparable to that of bulk samples. The numerical calculations using finite element method showed that without the screening of the applied field the levitation force of the bulk superconductor and the layered superconductor stack with a critical current of tapes increased by the filling factor is exactly the same, and taking into account the screening force slightly different.

Polyfluorophore Labels on DNA: Dramatic Sequence Dependence of Quenching

Science.gov (United States)

Teo, Yin Nah; Wilson, James N.

2010-01-01

We describe studies carried out in the DNA context to test how a common fluorescence quencher, dabcyl, interacts with oligodeoxynu-cleoside fluorophores (ODFs)—a system of stacked, electronically interacting fluorophores built on a DNA scaffold. We tested twenty different tetrameric ODF sequences containing varied combinations and orderings of pyrene (Y), benzopyrene (B), perylene (E), dimethylaminostilbene (D), and spacer (S) monomers conjugated to the 3′ end of a DNA oligomer. Hybridization of this probe sequence to a dabcyl-labeled complementary strand resulted in strong quenching of fluorescence in 85% of the twenty ODF sequences. The high efficiency of quenching was also established by their large Stern–Volmer constants (KSV) of between 2.1 × 104 and 4.3 × 105M−1, measured with a free dabcyl quencher. Interestingly, quenching of ODFs displayed strong sequence dependence. This was particularly evident in anagrams of ODF sequences; for example, the sequence BYDS had a KSV that was approximately two orders of magnitude greater than that of BSDY, which has the same dye composition. Other anagrams, for example EDSY and ESYD, also displayed different responses upon quenching by dabcyl. Analysis of spectra showed that apparent excimer and exciplex emission bands were quenched with much greater efficiency compared to monomer emission bands by at least an order of magnitude. This suggests an important role played by delocalized excited states of the π stack of fluorophores in the amplified quenching of fluorescence. PMID:19780115

Start-Stop Test Procedures on the PEMFC Stack Level

DEFF Research Database (Denmark)

Mitzel, Jens; Nygaard, Frederik; Veltzé, Sune

The test is addressed to investigate the influence on stack durability of a long stop followed by a restart of a stack. Long stop should be defined as a stop in which the anodic compartment is fully filled by air due to stack leakages. In systems, leakage level of the stack is low and time to fil...

SRS reactor stack plume marking tests

International Nuclear Information System (INIS)

Petry, S.F.

1992-03-01

Tests performed in 105-K in 1987 and 1988 demonstrated that the stack plume can successfully be made visible (i.e., marked) by introducing smoke into the stack breech. The ultimate objective of these tests is to provide a means during an emergency evacuation so that an evacuee can readily identify the stack plume and evacuate in the opposite direction, thus minimizing the potential of severe radiation exposure. The EPA has also requested DOE to arrange for more tests to settle a technical question involving the correct calculation of stack downwash. New test canisters were received in 1988 designed to produce more smoke per unit time; however, these canisters have not been evaluated, because normal ventilation conditions have not been reestablished in K Area. Meanwhile, both the authorization and procedure to conduct the tests have expired. The tests can be performed during normal reactor operation. It is recommended that appropriate authorization and procedure approval be obtained to resume testing after K Area restart

Trace interpolation by slant-stack migration

International Nuclear Information System (INIS)

Novotny, M.

1990-01-01

The slant-stack migration formula based on the radon transform is studied with respect to the depth steep Δz of wavefield extrapolation. It can be viewed as a generalized trace-interpolation procedure including wave extrapolation with an arbitrary step Δz. For Δz > 0 the formula yields the familiar plane-wave decomposition, while for Δz > 0 it provides a robust tool for migration transformation of spatially under sampled wavefields. Using the stationary phase method, it is shown that the slant-stack migration formula degenerates into the Rayleigh-Sommerfeld integral in the far-field approximation. Consequently, even a narrow slant-stack gather applied before the diffraction stack can significantly improve the representation of noisy data in the wavefield extrapolation process. The theory is applied to synthetic and field data to perform trace interpolation and dip reject filtration. The data examples presented prove that the radon interpolator works well in the dip range, including waves with mutual stepouts smaller than half the dominant period

Development of Auto-Stacking Warehouse Truck

Directory of Open Access Journals (Sweden)

Kuo-Hsien Hsia

2018-03-01

Full Text Available Warehouse automation is a very important issue for the promotion of traditional industries. For the production of larger and stackable products, it is usually necessary to operate a fork-lifter for the stacking and storage of the products by a skilled person. The general autonomous warehouse-truck does not have the ability of stacking objects. In this paper, we develop a prototype of auto-stacking warehouse-truck that can work without direct operation by a skill person. With command made by an RFID card, the stacker truck can take the packaged product to the warehouse on the prior-planned route and store it in a stacking way in the designated storage area, or deliver the product to the shipping area or into the container from the storage area. It can significantly reduce the manpower requirements of the skilled-person of forklift technician and improve the safety of the warehousing area.

Viewport: an object-oriented approach to integrate workstation software for tile and stack mode display.

Science.gov (United States)

Ghosh, S; Andriole, K P; Avrin, D E

1997-08-01

Diagnostic workstation design has migrated towards display presentation in one of two modes: tiled images or stacked images. It is our impression that the workstation setup or configuration in each of these two modes is rather distinct. We sought to establish a commonality to simplify software design, and to enable a single descriptor method to facilitate folder manager development of "hanging" protocols. All current workstation designs use a combination of "off-screen" and "on-screen" memory whether or not they use a dedicated display subsystem, or merely a video board. Most diagnostic workstations also have two or more monitors. Our central concept is that of a "logical" viewport that can be smaller than, the same size as, or larger than a single monitor. Each port "views" an image data sequence loaded into offscreen memory. Each viewport can display one or more images in sequence in a one-on-one or traditionally tiled presentation. Viewports can be assigned to the available monitor "real estate" in any manner that fits. For example, a single sequence computed tomography (CT) study could be displayed across all monitors in a tiled appearance by assigning a single large viewport to the monitors. At the other extreme, a multisequence magnetic resonance (MR) study could be compared with a similar previous study by assigning four viewports to each monitor, single image display per viewport, and assigning four of the sequences of the current study to the left monitor viewports, and four of the earlier study to the right monitor viewports. Ergonomic controls activate scrolling through the off-screen image sequence data. Workstation folder manager hanging protocols could then specify viewports, number of images per viewport, and the automatic assignment of appropriately named sequences of current and previous studies to the viewports on a radiologist-specific basis. Furthermore, software development is simplified by common base objects and methods of the tile and stack

40 CFR 61.44 - Stack sampling.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.44 Section 61.44 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... Firing § 61.44 Stack sampling. (a) Sources subject to § 61.42(b) shall be continuously sampled, during...

SOFC - Manufacture of stacks for test and demonstration related activities, stack and system tests and identification of end user requirements. Final report

Energy Technology Data Exchange (ETDEWEB)

Jacobsen, Joachim; Primdahl, S.; Boegh Elmose, H.; Weineisen, H.; Richter, A.

2008-11-15

The aim of the project was to solve the technical challenges in relation to stack functionality in connection with operation of multi stack assemblies under realistic operating conditions. It was the intention to make a targeted effort with the aim of developing a high performance stack technology suitable for both small and large units. An important part of the project was the testing of stack assemblies up to 10 kW power range with relevant fuel and realistic operation condition in the test facility at HC OErstedvaerket. The manufacturing of stacks in the project was as planned a number of stacks (70 kW) for use in demonstration projects both for single stacks and for multi stack assemblies. The start up of the work on the SOFC test facility at HC OErstedsvaerket (HCV) was delayed due to a late delivery of the unit from the PSO 6385 project. A number of unforeseen events during the project have meant that the SOFC test facility at HCV has not until now been ready for performing tests. The experience gained from the operation of a 20 kW Alpha unit in a co-operation between TOFC and Waertsilae now provides an important contribution to the future multi stack assemblies. The work on identification of end user requirements has resulted in a number of different development priorities for the m-CHP and the Distributed Generation market segments. (au)

Sharing programming resources between Bio* projects through remote procedure call and native call stack strategies.

Science.gov (United States)

Prins, Pjotr; Goto, Naohisa; Yates, Andrew; Gautier, Laurent; Willis, Scooter; Fields, Christopher; Katayama, Toshiaki

2012-01-01

Open-source software (OSS) encourages computer programmers to reuse software components written by others. In evolutionary bioinformatics, OSS comes in a broad range of programming languages, including C/C++, Perl, Python, Ruby, Java, and R. To avoid writing the same functionality multiple times for different languages, it is possible to share components by bridging computer languages and Bio* projects, such as BioPerl, Biopython, BioRuby, BioJava, and R/Bioconductor. In this chapter, we compare the two principal approaches for sharing software between different programming languages: either by remote procedure call (RPC) or by sharing a local call stack. RPC provides a language-independent protocol over a network interface; examples are RSOAP and Rserve. The local call stack provides a between-language mapping not over the network interface, but directly in computer memory; examples are R bindings, RPy, and languages sharing the Java Virtual Machine stack. This functionality provides strategies for sharing of software between Bio* projects, which can be exploited more often. Here, we present cross-language examples for sequence translation, and measure throughput of the different options. We compare calling into R through native R, RSOAP, Rserve, and RPy interfaces, with the performance of native BioPerl, Biopython, BioJava, and BioRuby implementations, and with call stack bindings to BioJava and the European Molecular Biology Open Software Suite. In general, call stack approaches outperform native Bio* implementations and these, in turn, outperform RPC-based approaches. To test and compare strategies, we provide a downloadable BioNode image with all examples, tools, and libraries included. The BioNode image can be run on VirtualBox-supported operating systems, including Windows, OSX, and Linux.

Generalized-stacking-fault energy and twin-boundary energy of hexagonal close-packed Au: A first-principles calculation.

Science.gov (United States)

Wang, Cheng; Wang, Huiyuan; Huang, Tianlong; Xue, Xuena; Qiu, Feng; Jiang, Qichuan

2015-05-22

Although solid Au is usually most stable as a face-centered cubic (fcc) structure, pure hexagonal close-packed (hcp) Au has been successfully fabricated recently. However, the phase stability and mechanical property of this new material are unclear, which may restrict its further applications. Here we present the evidence that hcp → fcc phase transformation can proceed easily in Au by first-principles calculations. The extremely low generalized-stacking-fault (GSF) energy in the basal slip system implies a great tendency to form basal stacking faults, which opens the door to phase transformation from hcp to fcc. Moreover, the Au lattice extends slightly within the superficial layers due to the self-assembly of alkanethiolate species on hcp Au (0001) surface, which may also contribute to the hcp → fcc phase transformation. Compared with hcp Mg, the GSF energies for non-basal slip systems and the twin-boundary (TB) energies for and twins are larger in hcp Au, which indicates the more difficulty in generating non-basal stacking faults and twins. The findings provide new insights for understanding the nature of the hcp → fcc phase transformation and guide the experiments of fabricating and developing materials with new structures.

Synthesis of carbon nanotubes from palm oil on stacking and non-stacking substrate by thermal-CVD method

Science.gov (United States)

Robaiah, M.; Rusop, M.; Abdullah, S.; Khusaimi, Z.; Azhan, H.; Fadzlinatul, M. Y.; Salifairus, M. J.; Asli, N. A.

2018-05-01

Palm oil has been used as the carbon source to synthesize carbon nanotubes (CNTs) on silicon substrates using the thermal chemical vapor deposition (CVD) method. Meanwhile, silicon has been applied using two techniques, which are stacked technique and non-stacked technique. The CNTs were grown at the constant time of 30 minutes with various synthesis temperatures of 750 °C, 850 °C and 950 °C. The CNTs were characterized using micro-Raman spectroscopy and field emission scanning electron microscopy (FESEM). It was found that the density, growth rate, diameter and length of the CNTs produced were affected by the synthesis temperature. Moreover, the structure slightly changes were observed between CNTs obtained in SS and NSS. The synthesize temperature of 750 °C was considered as the suitable temperature for the production of CNTs due to low ID/IG ratio, which for stacked is 0.89 and non-stacked are 0.90. The possible explanation for the different morphology of the produced CNTs was also discussed.

On the "stacking fault" in copper

NARCIS (Netherlands)

Fransens, J.R.; Pleiter, F

2003-01-01

The results of a perturbed gamma-gamma angular correlations experiment on In-111 implanted into a properly cut single crystal of copper show that the defect known in the literature as "stacking fault" is not a planar faulted loop but a stacking fault tetrahedron with a size of 10-50 Angstrom.

Resolution enhancement of robust Bayesian pre-stack inversion in the frequency domain

Science.gov (United States)

Yin, Xingyao; Li, Kun; Zong, Zhaoyun

2016-10-01

AVO/AVA (amplitude variation with an offset or angle) inversion is one of the most practical and useful approaches to estimating model parameters. So far, publications on AVO inversion in the Fourier domain have been quite limited in view of its poor stability and sensitivity to noise compared with time-domain inversion. For the resolution and stability of AVO inversion in the Fourier domain, a novel robust Bayesian pre-stack AVO inversion based on the mixed domain formulation of stationary convolution is proposed which could solve the instability and achieve superior resolution. The Fourier operator will be integrated into the objective equation and it avoids the Fourier inverse transform in our inversion process. Furthermore, the background constraints of model parameters are taken into consideration to improve the stability and reliability of inversion which could compensate for the low-frequency components of seismic signals. Besides, the different frequency components of seismic signals can realize decoupling automatically. This will help us to solve the inverse problem by means of multi-component successive iterations and the convergence precision of the inverse problem could be improved. So, superior resolution compared with the conventional time-domain pre-stack inversion could be achieved easily. Synthetic tests illustrate that the proposed method could achieve high-resolution results with a high degree of agreement with the theoretical model and verify the quality of anti-noise. Finally, applications on a field data case demonstrate that the proposed method could obtain stable inversion results of elastic parameters from pre-stack seismic data in conformity with the real logging data.

Numerical model for stack gas diffusion in terrain with buildings. Variations in air flow and gas concentration with additional building near stack

International Nuclear Information System (INIS)

Sada, Koichi; Michioka, Takenobu; Ichikawa, Yoichi; Komiyama, Sumito; Numata, Kunio

2009-01-01

A numerical simulation method for predicting atmospheric flow and stack gas diffusion using a calculation domain of several km around a stack under complex terrain conditions containing buildings has been developed. The turbulence closure technique using a modified k-ε-type model without a hydrostatic approximation was used for flow calculation, and some of the calculation grids near the ground were treated as buildings using a terrain-following coordinate system. Stack gas diffusion was predicted using the Lagrangian particle model, that is, the stack gas was represented by trajectories of released particles. The developed numerical model was applied to a virtual terrain and building conditions in this study prior to the applications of a numerical model for real terrain and building conditions. The height of the additional building (H a ), located about 200 m leeward from the stack, was varied (i.e., H a =0, 20, 30 and 50 m), and its effects on airflow and the concentration of stack gas at a released height of 75 m were calculated. Furthermore, effective stack height, which was used in the safety analysis of atmospheric diffusion for nuclear facilities in Japan, was evaluated from the calculated ground-level concentration of stack gas. The cavity region behind the additional building was calculated, and turbulence near the cavity was observed to decrease when the additional building was present. According to these flow variations with the additional building, tracer gas tended to diffuse to the ground surface rapidly with the additional building at the leeward position of the cavity, and the ground-level stack gas concentration along the plume axis also increased with the height of the additional building. However, the variations in effective stack height with the height of the additional building were relatively small and ranged within several m in this study. (author)

Density of oxidation-induced stacking faults in damaged silicon

NARCIS (Netherlands)

Kuper, F.G.; Hosson, J.Th.M. De; Verwey, J.F.

1986-01-01

A model for the relation between density and length of oxidation-induced stacking faults on damaged silicon surfaces is proposed, based on interactions of stacking faults with dislocations and neighboring stacking faults. The model agrees with experiments.

High-Density Stacked Ru Nanocrystals for Nonvolatile Memory Application

International Nuclear Information System (INIS)

Ping, Mao; Zhi-Gang, Zhang; Li-Yang, Pan; Jun, Xu; Pei-Yi, Chen

2009-01-01

Stacked ruthenium (Ru) nanocrystals (NCs) are formed by rapid thermal annealing for the whole gate stacks and embedded in memory structure, which is compatible with conventional CMOS technology. Ru NCs with high density (3 × 10 12 cm −2 ), small size (2–4 nm) and good uniformity both in aerial distribution and morphology are formed. Attributed to the higher surface trap density, a memory window of 5.2 V is obtained with stacked Ru NCs in comparison to that of 3.5 V with single-layer samples. The stacked Ru NCs device also exhibits much better retention performance because of Coulomb blockade and vertical uniformity between stacked Ru NCs

Vertical melting of a stack of membranes

Science.gov (United States)

Borelli, M. E. S.; Kleinert, H.; Schakel, A. M. J.

2001-02-01

A stack of tensionless membranes with nonlinear curvature energy and vertical harmonic interaction is studied. At low temperatures, the system forms a lamellar phase. At a critical temperature, the stack disorders vertically in a melting-like transition.

Role of sequence and structural polymorphism on the mechanical properties of amyloid fibrils.

Directory of Open Access Journals (Sweden)

Gwonchan Yoon

Full Text Available Amyloid fibrils playing a critical role in disease expression, have recently been found to exhibit the excellent mechanical properties such as elastic modulus in the order of 10 GPa, which is comparable to that of other mechanical proteins such as microtubule, actin filament, and spider silk. These remarkable mechanical properties of amyloid fibrils are correlated with their functional role in disease expression. This suggests the importance in understanding how these excellent mechanical properties are originated through self-assembly process that may depend on the amino acid sequence. However, the sequence-structure-property relationship of amyloid fibrils has not been fully understood yet. In this work, we characterize the mechanical properties of human islet amyloid polypeptide (hIAPP fibrils with respect to their molecular structures as well as their amino acid sequence by using all-atom explicit water molecular dynamics (MD simulation. The simulation result suggests that the remarkable bending rigidity of amyloid fibrils can be achieved through a specific self-aggregation pattern such as antiparallel stacking of β strands (peptide chain. Moreover, we have shown that a single point mutation of hIAPP chain constituting a hIAPP fibril significantly affects the thermodynamic stability of hIAPP fibril formed by parallel stacking of peptide chain, and that a single point mutation results in a significant change in the bending rigidity of hIAPP fibrils formed by antiparallel stacking of β strands. This clearly elucidates the role of amino acid sequence on not only the equilibrium conformations of amyloid fibrils but also their mechanical properties. Our study sheds light on sequence-structure-property relationships of amyloid fibrils, which suggests that the mechanical properties of amyloid fibrils are encoded in their sequence-dependent molecular architecture.

Multilayer Piezoelectric Stack Actuator Characterization

Science.gov (United States)

Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph

2008-01-01

Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

Characterization of Piezoelectric Stacks for Space Applications

Science.gov (United States)

Sherrit, Stewart; Jones, Christopher; Aldrich, Jack; Blodget, Chad; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph

2008-01-01

Future NASA missions are increasingly seeking to actuate mechanisms to precision levels in the nanometer range and below. Co-fired multilayer piezoelectric stacks offer the required actuation precision that is needed for such mechanisms. To obtain performance statistics and determine reliability for extended use, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and high temperatures and voltages. In order to study the lifetime performance of these stacks, five actuators were driven sinusoidally for up to ten billion cycles. An automated data acquisition system was developed and implemented to monitor each stack's electrical current and voltage waveforms over the life of the test. As part of the monitoring tests, the displacement, impedance, capacitance and leakage current were measured to assess the operation degradation. This paper presents some of the results of this effort.

Turbostratic stacked CVD graphene for high-performance devices

Science.gov (United States)

Uemura, Kohei; Ikuta, Takashi; Maehashi, Kenzo

2018-03-01

We have fabricated turbostratic stacked graphene with high-transport properties by the repeated transfer of CVD monolayer graphene. The turbostratic stacked CVD graphene exhibited higher carrier mobility and conductivity than CVD monolayer graphene. The electron mobility for the three-layer turbostratic stacked CVD graphene surpassed 10,000 cm2 V-1 s-1 at room temperature, which is five times greater than that for CVD monolayer graphene. The results indicate that the high performance is derived from maintenance of the linear band dispersion, suppression of the carrier scattering, and parallel conduction. Therefore, turbostratic stacked CVD graphene is a superior material for high-performance devices.

OpenStack augstas pieejamības risinājumi

OpenAIRE

Dreiže, Toms

2016-01-01

Šis bakalaura darbs ir pētījums par OpenStack IaaS mākoņpakalpojumu platformu. Tā mērķis ir sniegt ieskatu augstas pieejamības pamatprincipos un OpenStack mākoņpakalpojumu platformas piedāvātajos augstas pieejamības nodrošināšanas risinājumos. Bakalaura darba gaitā ir veikta augsti pieejamas OpenStack trīs mezglu sistēmas uzstādīšana, izmantojot Galera Cluster datubāzu klasteri un HAProxy slodzes līdzsvarotāju. Tika pārbaudīta OpenStack augsta pieejamība, testējot OpenStack Glance komponentes...

Efficiency of Polymer Electrolyte Membrane Fuel Cell Stack

Directory of Open Access Journals (Sweden)

Hans Bosma

2011-08-01

Full Text Available This paper applies a feedforward control of optimal oxygen excess ratio that maximize net power (improve efficiency of a NedStack P8.0-64 PEM fuel cell stack (FCS system. Net powers profile as a function of oxygen excess ratio for some points of operation are analyzed by using FCS model. The relationships between stack current and the corresponding control input voltage that gives an optimal oxygen excess ratio are used to design a feedforward control scheme. The results of this scheme are compared to the results of a feedforward control using a constant oxygen excess ratio. Simulation results show that optimal oxygen excess ratio improves fuel cell performance compared to the results of constant oxygen excess ratio. The same procedures are performed experimentally for the FCS system. The behaviour of the net power of the fuel cell stack with respect to the variation of oxygen excess ratio is analyzed to obtain optimal values. Data of stack current and the corresponding voltage input to the compressor that gives optimal values of oxygen excess ratio are used to develop a feedforward control. Feedforward control based on constant and optimal oxygen excess ratio control, are implemented in the NedStack P8.0-64 PEM fuel cell stack system by using LabVIEW. Implementation results shows that optimal oxygen excess ratio control improves the fuel cell performance compared to the constant oxygen excess ratio control.

Description of gasket failure in a 7 cell PEMFC stack

Energy Technology Data Exchange (ETDEWEB)

Husar, Attila; Serra, Maria [Institut de Robotica i Informatica Industrial, Parc Tecnologic de Barcelona, Edifici U, C. Llorens i Artigas, 4-6, 2a Planta, 08028 Barcelona (Spain); Kunusch, Cristian [Laboratorio de Electronica Industrial Control e Instrumentacion, Facultad de Ingenieria, UNLP (Argentina)

2007-06-10

This article presents the data and the description of a fuel cell stack that failed due to gasket degradation. The fuel cell under study is a 7 cell stack. The unexpected change in several variables such as temperature, pressure and voltage indicated the possible failure of the stack. The stack was monitored over a 6 h period in which data was collected and consequently analyzed to conclude that the fuel cell stack failed due to a crossover leak on the anode inlet port located on the cathode side gasket of cell 2. This stack failure analysis revealed a series of indicators that could be used by a super visional controller in order to initiate a shutdown procedure. (author)

400 W High Temperature PEM Fuel Cell Stack Test

DEFF Research Database (Denmark)

Andreasen, Søren Juhl; Kær, Søren Knudsen

2006-01-01

This work demonstrates the operation of a 30 cell high temperature PEM (HTPEM) fuel cell stack. This prototype stack has been developed at the Institute of Energy Technology, Aalborg University, as a proof-of-concept for a low pressure cathode air cooled HTPEM stack. The membranes used are Celtec...

Dynamic Model of High Temperature PEM Fuel Cell Stack Temperature

DEFF Research Database (Denmark)

Andreasen, Søren Juhl; Kær, Søren Knudsen

2007-01-01

cathode air cooled 30 cell HTPEM fuel cell stack developed at the Institute of Energy Technology at Aalborg University. This fuel cell stack uses PEMEAS Celtec P-1000 membranes, runs on pure hydrogen in a dead end anode configuration with a purge valve. The cooling of the stack is managed by running......The present work involves the development of a model for predicting the dynamic temperature of a high temperature PEM (HTPEM) fuel cell stack. The model is developed to test different thermal control strategies before implementing them in the actual system. The test system consists of a prototype...... the stack at a high stoichiometric air flow. This is possible because of the PBI fuel cell membranes used, and the very low pressure drop in the stack. The model consists of a discrete thermal model dividing the stack into three parts: inlet, middle and end and predicting the temperatures in these three...

Thin Co/Ni-based bottom pinned spin-transfer torque magnetic random access memory stacks with high annealing tolerance

Energy Technology Data Exchange (ETDEWEB)

Tomczak, Y., E-mail: Yoann.Tomczak@imec.be [IMEC Kapeldreef 75, B-3001 Leuven (Belgium); Department of Chemistry, KU Leuven (University of Leuven), Celestijnenlaan 200F, B-3001 Leuven (Belgium); Swerts, J.; Mertens, S.; Lin, T.; Couet, S.; Sankaran, K.; Pourtois, G.; Kim, W.; Souriau, L.; Van Elshocht, S.; Kar, G.; Furnemont, A. [IMEC Kapeldreef 75, B-3001 Leuven (Belgium); Liu, E. [Department of Chemistry, KU Leuven (University of Leuven), Celestijnenlaan 200F, B-3001 Leuven (Belgium)

2016-01-25

Spin-transfer torque magnetic random access memory (STT-MRAM) is considered as a replacement for next generation embedded and stand-alone memory applications. One of the main challenges in the STT-MRAM stack development is the compatibility of the stack with CMOS process flows in which thermal budgets up to 400 °C are applied. In this letter, we report on a perpendicularly magnetized MgO-based tunnel junction (p-MTJ) on a thin Co/Ni perpendicular synthetic antiferromagnetic layer with high annealing tolerance. Tunnel magneto resistance (TMR) loss after annealing occurs when the reference layer loses its perpendicular magnetic anisotropy due to reduction of the CoFeB/MgO interfacial anisotropy. A stable Co/Ni based p-MTJ stack with TMR values of 130% at resistance-area products of 9 Ω μm{sup 2} after 400 °C anneal is achieved via moment control of the Co/Ta/CoFeB reference layer. Thinning of the CoFeB polarizing layer down to 0.8 nm is the key enabler to achieve 400 °C compatibility with limited TMR loss. Thinning the Co below 0.6 nm leads to a loss of the antiferromagnetic interlayer exchange coupling strength through Ru. Insight into the thickness and moment engineering of the reference layer is displayed to obtain the best magnetic properties and high thermal stability for thin Co/Ni SAF-based STT-MRAM stacks.

Enhancement of stack ventilation in hot and humid climate using a combination of roof solar collector and vertical stack

Energy Technology Data Exchange (ETDEWEB)

Yusoff, Wardah Fatimah Mohammad; Salleh, Elias [Department of Architecture, Faculty of Design and Architecture, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Adam, Nor Mariah [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Sapian, Abdul Razak [Department of Architecture, Kulliyyah of Architecture and Environmental Design, International Islamic University Malaysia, P.O. Box 10, 50728 Kuala Lumpur (Malaysia); Yusof Sulaiman, Mohamad [Solar Energy Research Institute, 3rd Floor, Tun Sri Lanang Library Building, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

2010-10-15

In the hot and humid climate, stack ventilation is inefficient due to small temperature difference between the inside and outside of naturally ventilated buildings. Hence, solar induced ventilation is a feasible alternative in enhancing the stack ventilation. This paper aims to investigate the effectiveness of a proposed solar induced ventilation strategy, which combines a roof solar collector and a vertical stack, in enhancing the stack ventilation performance in the hot and humid climate. The methodology selected for the investigation is physical experimental modelling which was carried out in the actual environment. The results are presented and discussed in terms of two performance variables: air temperature and air velocity. The findings indicate that the proposed strategy is able to enhance the stack ventilation, both in semi-clear sky and overcast sky conditions. The highest air temperature difference between the air inside the stack and the ambient air (T{sub i}-T{sub o}) is achieved in the semi-clear sky condition, which is about 9.9 C (45.8 C-35.9 C). Meanwhile, in the overcast sky condition, the highest air temperature difference (T{sub i}-T{sub o}) is 6.2 C (39.3 C-33.1 C). The experimental results also indicate good agreement with the theoretical results for the glass temperature, the air temperature in the roof solar collector's channel and the absorber temperature. The findings also show that wind has significant effect to the induced air velocity by the proposed strategy. (author)

Learning SaltStack

CERN Document Server

Myers, Colton

2015-01-01

If you are a system administrator who manages multiple servers, then you know how difficult it is to keep your infrastructure in line. If you've been searching for an easier way, this book is for you. No prior experience with SaltStack is required.

Fast principal component analysis for stacking seismic data

Science.gov (United States)

Wu, Juan; Bai, Min

2018-04-01

Stacking seismic data plays an indispensable role in many steps of the seismic data processing and imaging workflow. Optimal stacking of seismic data can help mitigate seismic noise and enhance the principal components to a great extent. Traditional average-based seismic stacking methods cannot obtain optimal performance when the ambient noise is extremely strong. We propose a principal component analysis (PCA) algorithm for stacking seismic data without being sensitive to noise level. Considering the computational bottleneck of the classic PCA algorithm in processing massive seismic data, we propose an efficient PCA algorithm to make the proposed method readily applicable for industrial applications. Two numerically designed examples and one real seismic data are used to demonstrate the performance of the presented method.

Stacked Heterogeneous Neural Networks for Time Series Forecasting

Directory of Open Access Journals (Sweden)

Florin Leon

2010-01-01

Full Text Available A hybrid model for time series forecasting is proposed. It is a stacked neural network, containing one normal multilayer perceptron with bipolar sigmoid activation functions, and the other with an exponential activation function in the output layer. As shown by the case studies, the proposed stacked hybrid neural model performs well on a variety of benchmark time series. The combination of weights of the two stack components that leads to optimal performance is also studied.

Method for applying a thin film barrier stack to a device with microstructures, and device provided with such a thin film barrier stack

NARCIS (Netherlands)

2005-01-01

A method for applying a thin film barrier stack to a device with microstructures, such as, for instance, an OLED, wherein the thin film barrier stack forms a barrier to at least moisture and oxygen, wherein the stack is built up from a combination of org. and inorg. layers, characterized in that a

Captioning Transformer with Stacked Attention Modules

Directory of Open Access Journals (Sweden)

Xinxin Zhu

2018-05-01

Full Text Available Image captioning is a challenging task. Meanwhile, it is important for the machine to understand the meaning of an image better. In recent years, the image captioning usually use the long-short-term-memory (LSTM as the decoder to generate the sentence, and these models show excellent performance. Although the LSTM can memorize dependencies, the LSTM structure has complicated and inherently sequential across time problems. To address these issues, recent works have shown benefits of the Transformer for machine translation. Inspired by their success, we develop a Captioning Transformer (CT model with stacked attention modules. We attempt to introduce the Transformer to the image captioning task. The CT model contains only attention modules without the dependencies of the time. It not only can memorize dependencies between the sequence but also can be trained in parallel. Moreover, we propose the multi-level supervision to make the Transformer achieve better performance. Extensive experiments are carried out on the challenging MSCOCO dataset and the proposed Captioning Transformer achieves competitive performance compared with some state-of-the-art methods.

Stack Monitor Operating Experience Review

International Nuclear Information System (INIS)

Cadwallader, L.C.; Bruyere, S.A.

2009-01-01

Stack monitors are used to sense radioactive particulates and gases in effluent air being vented from rooms of nuclear facilities. These monitors record the levels and types of effluents to the environment. This paper presents the results of a stack monitor operating experience review of the U.S. Department of Energy (DOE) Occurrence Reporting and Processing System (ORPS) database records from the past 18 years. Regulations regarding these monitors are briefly described. Operating experiences reported by the U.S. DOE and in engineering literature sources were reviewed to determine the strengths and weaknesses of these monitors. Electrical faults, radiation instrumentation faults, and human errors are the three leading causes of failures. A representative 'all modes' failure rate is 1E-04/hr. Repair time estimates vary from an average repair time of 17.5 hours (with spare parts on hand) to 160 hours (without spare parts on hand). These data should support the use of stack monitors in any nuclear facility, including the National Ignition Facility and the international ITER project.

Manipulative interplay of two adozelesin molecules with d(ATTAAT)₂achieving ligand-stacked Watson-Crick and Hoogsteen base-paired duplex adducts.

Science.gov (United States)

Hopton, Suzanne R; Thompson, Andrew S

2011-05-17

Previous structural studies of the cyclopropapyrroloindole (CPI) antitumor antibiotics have shown that these ligands bind covalently edge-on into the minor groove of double-stranded DNA. Reversible covalent modification of the DNA via N3 of adenine occurs in a sequence-specific fashion. Early nuclear magnetic resonance and molecular modeling studies with both mono- and bis-alkylating ligands indicated that the ligands fit tightly within the minor groove, causing little distortion of the helix. In this study, we propose a new binding model for several of the CPI-based analogues, in which the aromatic secondary rings form π-stacked complexes within the minor groove. One of the adducts, formed with adozelesin and the d(ATTAAT)(2) sequence, also demonstrates the ability of these ligands to manipulate the DNA of the binding site, resulting in a Hoogsteen base-paired adduct. Although this type of base pairing has been previously observed with the bisfunctional CPI analogue bizelesin, this is the first time that such an observation has been made with a monoalkylating nondimeric analogue. Together, these results provide a new model for the design of CPI-based antitumor antibiotics, which also has a significant bearing on other structurally related and structurally unrelated minor groove-binding ligands. They indicate the dynamic nature of ligand-DNA interactions, demonstrating both DNA conformational flexibility and the ability of two DNA-bound ligands to interact to form stable covalent modified complexes.

Study and Development of an OpenStack solution

OpenAIRE

Jorba Brosa, Maria

2014-01-01

Estudi i desenvolupament d'una solució de virtualització amb Openstack. Es farà un especial èmfasi en la part de seguretat. Deployment of a solution based in OpenStack for the creation of an Infrastructure service cloud. Implementación de una solución basada en OpenStack para la creación de una infrastructura de servicios cloud. Implementació d'una solució basada en OpenStack per la creació d'una infrastructura de serveis cloud.

Developments for improved direct methanol fuel cell stacks for portable power

Energy Technology Data Exchange (ETDEWEB)

Cremers, C.; Stimming, U. [Bavarian Center for Applied Energy Research, ZAE Bayern, Abteilung 1, Walther-Meissner-Str. 6, D-85748 Garching (Germany); Technische Universitaet Muenchen, Department of Physics E19, James-Franck-Str. 1, D-85748 Garching (Germany); Scholz, M.; Seliger, W. [Bavarian Center for Applied Energy Research, ZAE Bayern, Abteilung 1, Walther-Meissner-Str. 6, D-85748 Garching (Germany); Racz, A. [Technische Universitaet Muenchen, Department of Physics E19, James-Franck-Str. 1, D-85748 Garching (Germany); Knechtel, W.; Rittmayr, J.; Grafwallner, F.; Peller, H. [ET EnergieTechnologie GmbH, Eugen-Saenger-Ring 4, D-85649 Brunnthal-Nord (Germany)

2007-02-15

Different aspects of the improvement of direct methanol fuel cell (DMFC) systems for portable power generation are investigated, in a project funded by the Bavarian state. The materials research focuses on the development of improved catalysts, in particular for the oxygen reduction reaction. Some recent results on supported ruthenium selenium catalysts are reported. In parallel, tests on other fuel cell materials are performed using MEAs made from industrial unsupported catalysts as the reference. These standard MEAs have catalyst loadings of about 11 mg cm{sup -2} and, at high air flux, can deliver current densities of about 500 mA cm{sup -2} and 100 mA cm{sup -2} at 110 C and 50 C, respectively. At low air flux and 50 C, current densities between 60 and 80 mA cm{sup -2} are possible rate at 500 mV. Using these MEAs, different commercial gas diffusion materials are tested as the cathode backing. Thus, it is found that the Sigracet materials by SGL Carbon are the most suitable for operation at a low air flux. Finally, a demonstration stack, comprised of up to ten cells, is developed using graphite PVDF compound bipolar plates by SGL Carbon. As will be reported, this stack shows a high homogeneity of cell voltages and stable operation under relevant conditions, using standard MEAs. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Exploring online evolution of network stacks

OpenAIRE

Imai, Pierre

2013-01-01

Network stacks today follow a one-size-fits-all philosophy. They are mostly kept unmodified due to often prohibitive costs of engineering, deploying and administrating customisation of the networking software, with the Internet stack architecture still largely being based on designs and assumptions made for the ARPANET 40 years ago. We venture that heterogeneous and rapidly changing networks of the future require, in order to be successful, run-time self-adaptation mechanisms at different tim...

Radiation damage and life-time evaluation of RBMK graphite stack

Energy Technology Data Exchange (ETDEWEB)

Platonov, P A; Chugunov, O K; Manevsky, V N; Karpukhin, V I [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation). Reactor Material Div.

1996-08-01

At the present time there are 11 NPP units with RBMK reactors in operation in Russia, with the oldest now in operation 22 years. Design life-time of the RBMK-1000 reactor is 30 years. This paper addresses the evaluation of RBMK graphite stack life-time. It is the practice in Russia to evaluate the reliability of the channel reactor graphite stack using at least three criteria: degradation of physical-mechanical properties of graphite, preservation of the graphite brick integrity, and degradation of the graphite stack as a structure. Stack life-time evaluation by different criteria indicates that the most realistic approach may be realized on the basis of the criteria of brick cracking and degradation of the graphite stack as a structure. The RBMK reactor graphite stack life-time depends on its temperature and for different units it may be different. (author). 2 refs, 10 figs.

Vector Fields and Flows on Differentiable Stacks

DEFF Research Database (Denmark)

A. Hepworth, Richard

2009-01-01

This paper introduces the notions of vector field and flow on a general differentiable stack. Our main theorem states that the flow of a vector field on a compact proper differentiable stack exists and is unique up to a uniquely determined 2-cell. This extends the usual result on the existence...... of vector fields....

A high-performance aluminum-feed microfluidic fuel cell stack

Science.gov (United States)

Wang, Yifei; Leung, Dennis Y. C.

2016-12-01

In this paper, a six-cell microfluidic fuel cell (MFC) stack is demonstrated. Low-cost aluminum is fed directly to the stack, which produces hydrogen fuel on site, through the Al-H2O reaction. This design is not only cost-efficient, but also eliminates the need for hydrogen storage. Unlike the conventional MFC stacks which generally require complex electrolyte distribution and management, the present Al-feed MFC stack requires only a single electrolyte stream, flowing successively through individual cells, which is finally utilized for hydrogen generation. In this manner, the whole system is greatly simplified while the operational robustness is also improved. With 2 M sodium hydroxide solution as electrolyte and kitchen foil Al as fuel, the present six-cell stack (in series) exhibits an open circuit voltage of nearly 6 V and a peak power density of 180.6 mWcm-2 at room temperature. In addition, an energy density of 1 Whg-1(Al) is achieved, which is quite high and comparable with its proton exchange membrane-based counterparts. Finally, pumpless operation of the present stack, together with its practical applications are successfully demonstrated, including lightening LED lights, driving an electric fan, and cell phone charging.

Dynamic stack testing and HiL simulation

Energy Technology Data Exchange (ETDEWEB)

Randolf, G. [GRandalytics, Honolulu, HI (United States)

2009-07-01

The applications for fuel cell and stack deployment have changed rapidly over the years, from stationary backup supplies to highly dynamic automotive power systems. As a result, testing must keep up in order to ensure mature products of high quality. A new breed of stack test stations has been designed, based on a newly developed single cell, high dynamic hardware-in-the-loop (HiL) simulator in order to meet the growing demand of realistic fuel cell testing scenarios for aviation and automotive industries. The paper described and illustrated the test station architecture and outline of communication nodes. The paper also described the voltage monitor and presented schematics of voltage monitoring modules. The basic requirements of the architecture that were presented included low latency; flexible communication with simulation targets and other data input/output nodes; scalability to various stack sizes; and, safety and reliability. It was concluded that first tests with the voltage monitoring system not only confirmed the design, high throughput and signal quality, but also suggested another application, namely a stack impedance spectrometer for each individual cell. 1 ref., 3 figs.

Experiences from design and testing of a small PEM fuel cell stack

International Nuclear Information System (INIS)

Lange, T.; Ofstad, A.B.; Moller-Holst, S.

2004-01-01

'Full text:' Introduction The Proton Exchange Membrane Fuel Cell (PEMFC) technology is considered the most promising candidate for mobile applications, due to its high power density, short start-up times and immediate response to changes in power demand. PEMFC systems tend, however, to become rather complex in order to provide for optimum water and thermal management, and facilitate stable operation. Auxiliary components add to cost and volume, and may reduce reliability. Pressurized operation may increase system power density, but to the sacrifice of efficiency. The atmospheric systems are inferior to pressurized systems with respect to water self-sufficiency and usually demand voluminous water condenser systems. At high power densities the amount of waste heat becomes considerable, and for larger systems liquid cooling is usually inevitable. But even for smaller, air-cooled systems, thermal management is challenging because of the relatively small temperature difference between the fuel cell and the surroundings. Over more than a decade there has been a trend towards simpler PEMFC systems holding a minimum number of auxiliary components, operating at atmospheric pressure and utilizing various self-humidifying techniques. However, due to the complexity of PEMFC operation, the degree of simplification becomes a trade-off between system cost and volume, and controllability. Experimental In the present work a small 10 cell PEMFC stack for demonstrational purposes was designed, assembled and tested. Commercial MEAs (Gore) and GDLs (E-TEK) were used. Thermocouples were inserted into the cathode air channels. Based on a total of 300 temperature measurements a semi-3-dimensional temperature distribution in the stack was obtained. Cell performance was characterized by obtaining polarization curves for each cell and measuring the steady state temperature distribution at a current density of 0.10 A/cm 2 . Results and Discussion Stable performance was obtained at 0.10 A/cm 2

Development of an Integrated Polymer Microfluidic Stack

International Nuclear Information System (INIS)

Datta, Proyag; Hammacher, Jens; Pease, Mark; Gurung, Sitanshu; Goettert, Jost

2006-01-01

Microfluidic is a field of considerable interest. While significant research has been carried out to develop microfluidic components, very little has been done to integrate the components into a complete working system. We present a flexible modular system platform that addresses the requirements of a complete microfluidic system. A microfluidic stack system is demonstrated with the layers of the stack being modular for specific functions. The stack and accompanying infrastructure provides an attractive platform for users to transition their design concepts into a working microfluidic system quickly with very little effort. The concept is demonstrated by using the system to carry out a chemilumiscence experiment. Details regarding the fabrication, assembly and experimental methods are presented

Thermal stress analysis of a planar SOFC stack

Science.gov (United States)

Lin, Chih-Kuang; Chen, Tsung-Ting; Chyou, Yau-Pin; Chiang, Lieh-Kwang

The aim of this study is, by using finite element analysis (FEA), to characterize the thermal stress distribution in a planar solid oxide fuel cell (SOFC) stack during various stages. The temperature profiles generated by an integrated thermo-electrochemical model were applied to calculate the thermal stress distributions in a multiple-cell SOFC stack by using a three-dimensional (3D) FEA model. The constructed 3D FEA model consists of the complete components used in a practical SOFC stack, including positive electrode-electrolyte-negative electrode (PEN) assembly, interconnect, nickel mesh, and gas-tight glass-ceramic seals. Incorporation of the glass-ceramic sealant, which was never considered in previous studies, into the 3D FEA model would produce more realistic results in thermal stress analysis and enhance the reliability of predicting potential failure locations in an SOFC stack. The effects of stack support condition, viscous behavior of the glass-ceramic sealant, temperature gradient, and thermal expansion mismatch between components were characterized. Modeling results indicated that a change in the support condition at the bottom frame of the SOFC stack would not cause significant changes in thermal stress distribution. Thermal stress distribution did not differ significantly in each unit cell of the multiple-cell stack due to a comparable in-plane temperature profile. By considering the viscous characteristics of the glass-ceramic sealant at temperatures above the glass-transition temperature, relaxation of thermal stresses in the PEN was predicted. The thermal expansion behavior of the metallic interconnect/frame had a greater influence on the thermal stress distribution in the PEN than did that of the glass-ceramic sealant due to the domination of interconnect/frame in the volume of a planar SOFC assembly.

Optimization of hole generation in Ti/CFRP stacks

Science.gov (United States)

Ivanov, Y. N.; Pashkov, A. E.; Chashhin, N. S.

2018-03-01

The article aims to describe methods for improving the surface quality and hole accuracy in Ti/CFRP stacks by optimizing cutting methods and drill geometry. The research is based on the fundamentals of machine building, theory of probability, mathematical statistics, and experiment planning and manufacturing process optimization theories. Statistical processing of experiment data was carried out by means of Statistica 6 and Microsoft Excel 2010. Surface geometry in Ti stacks was analyzed using a Taylor Hobson Form Talysurf i200 Series Profilometer, and in CFRP stacks - using a Bruker ContourGT-Kl Optical Microscope. Hole shapes and sizes were analyzed using a Carl Zeiss CONTURA G2 Measuring machine, temperatures in cutting zones were recorded with a FLIR SC7000 Series Infrared Camera. Models of multivariate analysis of variance were developed. They show effects of drilling modes on surface quality and accuracy of holes in Ti/CFRP stacks. The task of multicriteria drilling process optimization was solved. Optimal cutting technologies which improve performance were developed. Methods for assessing thermal tool and material expansion effects on the accuracy of holes in Ti/CFRP/Ti stacks were developed.

G-stack modulated probe intensities on expression arrays - sequence corrections and signal calibration

Directory of Open Access Journals (Sweden)

Fasold Mario

2010-04-01

Full Text Available Abstract Background The brightness of the probe spots on expression microarrays intends to measure the abundance of specific mRNA targets. Probes with runs of at least three guanines (G in their sequence show abnormal high intensities which reflect rather probe effects than target concentrations. This G-bias requires correction prior to downstream expression analysis. Results Longer runs of three or more consecutive G along the probe sequence and in particular triple degenerated G at its solution end ((GGG1-effect are associated with exceptionally large probe intensities on GeneChip expression arrays. This intensity bias is related to non-specific hybridization and affects both perfect match and mismatch probes. The (GGG1-effect tends to increase gradually for microarrays of later GeneChip generations. It was found for DNA/RNA as well as for DNA/DNA probe/target-hybridization chemistries. Amplification of sample RNA using T7-primers is associated with strong positive amplitudes of the G-bias whereas alternative amplification protocols using random primers give rise to much smaller and partly even negative amplitudes. We applied positional dependent sensitivity models to analyze the specifics of probe intensities in the context of all possible short sequence motifs of one to four adjacent nucleotides along the 25meric probe sequence. Most of the longer motifs are adequately described using a nearest-neighbor (NN model. In contrast, runs of degenerated guanines require explicit consideration of next nearest neighbors (GGG terms. Preprocessing methods such as vsn, RMA, dChip, MAS5 and gcRMA only insufficiently remove the G-bias from data. Conclusions Positional and motif dependent sensitivity models accounts for sequence effects of oligonucleotide probe intensities. We propose a positional dependent NN+GGG hybrid model to correct the intensity bias associated with probes containing poly-G motifs. It is implemented as a single-chip based calibration

Project W-420 stack monitoring system upgrades

International Nuclear Information System (INIS)

CARPENTER, K.E.

1999-01-01

This project will execute the design, procurement, construction, startup, and turnover activities for upgrades to the stack monitoring system on selected Tank Waste Remediation System (TWRS) ventilation systems. In this plan, the technical, schedule, and cost baselines are identified, and the roles and responsibilities of project participants are defined for managing the Stack Monitoring System Upgrades, Project W-420

Stress-induced formation mechanism of stacking fault tetrahedra in nano-cutting of single crystal copper

Energy Technology Data Exchange (ETDEWEB)

Wang, Quanlong [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Bai, Qingshun [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Chen, Jiaxuan, E-mail: wangquanlong0@hit.edu.cn [Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Guo, Yongbo [Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Xie, Wenkun [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2015-11-15

increase in the initial stage and fluctuates at their equilibrium position at stable cutting stage, which is because of the energy accumulation and release leading to the dislocation emission. A typically stacking fault tetrahedra is nucleated in the subsurface defect layer, which is induced by the complex tension and compression stress. The stress-induced mechanism of stacking fault tetrahedra formation is investigated by atomic scale evolution and local stress distribution.

Stress-induced formation mechanism of stacking fault tetrahedra in nano-cutting of single crystal copper

International Nuclear Information System (INIS)

Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Guo, Yongbo; Xie, Wenkun

2015-01-01

increase in the initial stage and fluctuates at their equilibrium position at stable cutting stage, which is because of the energy accumulation and release leading to the dislocation emission. A typically stacking fault tetrahedra is nucleated in the subsurface defect layer, which is induced by the complex tension and compression stress. The stress-induced mechanism of stacking fault tetrahedra formation is investigated by atomic scale evolution and local stress distribution.

Fabrication of high gradient insulators by stack compression

Science.gov (United States)

Harris, John Richardson; Sanders, Dave; Hawkins, Steven Anthony; Norona, Marcelo

2014-04-29

Individual layers of a high gradient insulator (HGI) are first pre-cut to their final dimensions. The pre-cut layers are then stacked to form an assembly that is subsequently pressed into an HGI unit with the desired dimension. The individual layers are stacked, and alignment is maintained, using a sacrificial alignment tube that is removed after the stack is hot pressed. The HGI's are used as high voltage vacuum insulators in energy storage and transmission structures or devices, e.g. in particle accelerators and pulsed power systems.

Validation of a HT-PEMFC stack for CHP applications

Energy Technology Data Exchange (ETDEWEB)

Pasupathi, S.; Ulleberg, Oe. [Western Cape Univ. (South Africa). HySA Systems, SAIAMC; Bujlo, P. [Western Cape Univ. (South Africa). HySA Systems, SAIAMC; Electrotechnical Institute Wroclaw Division (Poland); Scholta, J. [Centre for Solar Energy and Hydrogen Research (ZSW) (Germany)

2010-07-01

Fuel cell systems are very attractive for stationary co-generation applications as they can produce heat and electricity efficiently in a decentralized and environmentally friendly manner. PEMFC stacks operating at temperatures above 120 C, specifically in the range of 140-180 C, are ideal for co-generation purposes. In this study, preliminary results from a HTPEMFC stack designed for CHP applications is presented and discussed. A short, five-cell, HT-PEMFC stack was assembled with Celtec- P-2100 MEAs and validated in terms of electrical performance. The stack was operated with hydrogen and air at 160 C and the utilization curves for anode and cathode were recorded for a wide range of gas utilization at a current density of 0.52 A/cm{sup 2}. The current voltage characteristic was measured at optimal utilization values at 160 C. A 1kW stack is assembled and is currently being validated for its performance under various operating conditions for use in CHP applications. (orig.)

Routes to a commercially viable PEM fuel cell stack

Energy Technology Data Exchange (ETDEWEB)

Newton, J.; Foster, S.E.; Hodgson, D.; Marrett, A.

2002-07-01

This report describes the results of a project to design and build a 10 kW{sub e} proton exchange membrane fuel cell (PEMFC) stack, including membrane electrode assemblies (MEAs), bipolar plates and stack hardware. The aim was to prove the design concept and to demonstrate functionality by operating the stack at >1 kW{sub e}/L and 500 W/kg for 200 hours operation. The project was extended to include the assembly and testing of two additional 1 kW{sub e} PEMFC stacks based on coated metal components. Low equivalent weight perfluorinated ionomer ion exchange membranes were prepared and were found to give a superior electrochemical performance to commercial materials. A technique to etch various stainless steel grades and control processes was successfully developed and optimised. Coatings for stainless steel and titanium were successfully developed and met the required performance criteria. All PEMFC stack components were selected and designed to enable subsequent commercial manufacture.

Development of the electric utility dispersed use PAFC stack

Energy Technology Data Exchange (ETDEWEB)

Horiuchi, Hiroshi; Kotani, Ikuo [Mitsubishi Electric Co., Kobe (Japan); Morotomi, Isamu [Kansai Electric Power Co., Hyogo (Japan)] [and others

1996-12-31

Kansai Electric Power Co. and Mitsubishi Electric Co. have been developing the electric utility dispersed use PAFC stack operated under the ambient pressure. The new cell design have been developed, so that the large scale cell (1 m{sup 2} size) was adopted for the stack. To confirm the performance and the stability of the 1 m{sup 2} scale cell design, the short stack study had been performed.

Sport stacking activities in school children's motor skill development.

Science.gov (United States)

Li, Yuhua; Coleman, Diane; Ransdell, Mary; Coleman, Lyndsie; Irwin, Carol

2011-10-01

This study examined the impact of a 12-wk. sport stacking intervention on reaction time (RT), manual dexterity, and hand-eye coordination in elementary school-aged children. 80 Grade 2 students participated in a 15-min. sport stacking practice session every school day for 12 wk., and were tested on psychomotor performance improvement. Tests for choice RT, manual dexterity, and photoelectric rotary pursuit tracking were conducted pre- and post-intervention for both experimental group (n = 36) and the controls (n = 44) who did no sport stacking. Students who had the intervention showed a greater improvement in two-choice RT. No other group difference was found. Such sport stacking activities may facilitate children's central processing and perceptual-motor integration.

Simultaneous stack-gas scrubbing and waste water treatment

Science.gov (United States)

Poradek, J. C.; Collins, D. D.

1980-01-01

Simultaneous treatment of wastewater and S02-laden stack gas make both treatments more efficient and economical. According to results of preliminary tests, solution generated by stack gas scrubbing cycle reduces bacterial content of wastewater. Both processess benefit by sharing concentrations of iron.

Detailed Electrochemical Characterisation of Large SOFC Stacks

DEFF Research Database (Denmark)

Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, R.

2012-01-01

application of advanced methods for detailed electrochemical characterisation during operation. An operating stack is subject to steep compositional gradients in the gaseous reactant streams, and significant temperature gradients across each cell and across the stack, which makes it a complex system...... Fuel Cell A/S was characterised in detail using electrochemical impedance spectroscopy. An investigation of the optimal geometrical placement of the current probes and voltage probes was carried out in order to minimise measurement errors caused by stray impedances. Unwanted stray impedances...... are particularly problematic at high frequencies. Stray impedances may be caused by mutual inductance and stray capacitance in the geometrical set-up and do not describe the fuel cell. Three different stack geometries were investigated by electrochemical impedance spectroscopy. Impedance measurements were carried...

The Stack-Size of Combinatorial Tries Revisited

Directory of Open Access Journals (Sweden)

Markus E. Nebel

2002-12-01

Full Text Available In the present paper we consider a generalized class of extended binary trees in which leaves are distinguished in order to represent the location of a key within a trie of the same structure. We prove an exact asymptotic equivalent to the average stack-size of trees with α internal nodes and β leaves corresponding to keys; we assume that all trees with the same parameters α and β have the same probability. The assumption of that uniform model is motivated for example by the usage of tries for the compression of blockcodes. Furthermore, we will prove asymptotics for the r-th moments of the stack-size and we will show that a normalized stack-size possesses a theta distribution in the limit.

Electrochemical Detection in Stacked Paper Networks.

Science.gov (United States)

Liu, Xiyuan; Lillehoj, Peter B

2015-08-01

Paper-based electrochemical biosensors are a promising technology that enables rapid, quantitative measurements on an inexpensive platform. However, the control of liquids in paper networks is generally limited to a single sample delivery step. Here, we propose a simple method to automate the loading and delivery of liquid samples to sensing electrodes on paper networks by stacking multiple layers of paper. Using these stacked paper devices (SPDs), we demonstrate a unique strategy to fully immerse planar electrodes by aqueous liquids via capillary flow. Amperometric measurements of xanthine oxidase revealed that electrochemical sensors on four-layer SPDs generated detection signals up to 75% higher compared with those on single-layer paper devices. Furthermore, measurements could be performed with minimal user involvement and completed within 30 min. Due to its simplicity, enhanced automation, and capability for quantitative measurements, stacked paper electrochemical biosensors can be useful tools for point-of-care testing in resource-limited settings. © 2015 Society for Laboratory Automation and Screening.

Solid Oxide Cell and Stack Testing, Safety and Quality Assurance (SOCTESQA)

DEFF Research Database (Denmark)

Auer, C.; Lang, M.; Couturier, K.

2015-01-01

In the EU-funded project “SOCTESQA” partners from Europe and Singapore are working together to develop uniform and industry wide test procedures and protocols for solid oxide cells and stacks SOC cell/stack assembly. New application fields which are based on the operation of the SOC cell/stack as......In the EU-funded project “SOCTESQA” partners from Europe and Singapore are working together to develop uniform and industry wide test procedures and protocols for solid oxide cells and stacks SOC cell/stack assembly. New application fields which are based on the operation of the SOC cell...

Static analysis of worst-case stack cache behavior

DEFF Research Database (Denmark)

Jordan, Alexander; Brandner, Florian; Schoeberl, Martin

2013-01-01

Utilizing a stack cache in a real-time system can aid predictability by avoiding interference that heap memory traffic causes on the data cache. While loads and stores are guaranteed cache hits, explicit operations are responsible for managing the stack cache. The behavior of these operations can......-graph, the worst-case bounds can be efficiently yet precisely determined. Our evaluation using the MiBench benchmark suite shows that only 37% and 21% of potential stack cache operations actually store to and load from memory, respectively. Analysis times are modest, on average running between 0.46s and 1.30s per...

Optimized stacked RADFETs for milli-rad dose measurement

International Nuclear Information System (INIS)

O'Connell, B.; Lane, B.; Mohammadzadeh, A.

1999-01-01

This paper details the improvements in the design of stacked RADFETs for increased radiation sensitivity. The issues of high read-out voltage has been shown to be a draw-back. It is the body (bulk)effect factor that is responsible for the increased overall stack Threshold voltage (V T ), which is greater than the sum of the individual devices V T . From extensive process and device simulation and resultant circuit simulation, modified stack structures have been proposed and designed. New and exciting result of lower initial (pre-irradiation) output voltage as well as increased radiation sensitivity will be presented. (author)

Optoelectronic interconnects for 3D wafer stacks

Science.gov (United States)

Ludwig, David; Carson, John C.; Lome, Louis S.

1996-01-01

Wafer and chip stacking are envisioned as means of providing increased processing power within the small confines of a three-dimensional structure. Optoelectronic devices can play an important role in these dense 3-D processing electronic packages in two ways. In pure electronic processing, optoelectronics can provide a method for increasing the number of input/output communication channels within the layers of the 3-D chip stack. Non-free space communication links allow the density of highly parallel input/output ports to increase dramatically over typical edge bus connections. In hybrid processors, where electronics and optics play a role in defining the computational algorithm, free space communication links are typically utilized for, among other reasons, the increased network link complexity which can be achieved. Free space optical interconnections provide bandwidths and interconnection complexity unobtainable in pure electrical interconnections. Stacked 3-D architectures can provide the electronics real estate and structure to deal with the increased bandwidth and global information provided by free space optical communications. This paper will provide definitions and examples of 3-D stacked architectures in optoelectronics processors. The benefits and issues of these technologies will be discussed.

Reliability analysis and initial requirements for FC systems and stacks

Science.gov (United States)

Åström, K.; Fontell, E.; Virtanen, S.

In the year 2000 Wärtsilä Corporation started an R&D program to develop SOFC systems for CHP applications. The program aims to bring to the market highly efficient, clean and cost competitive fuel cell systems with rated power output in the range of 50-250 kW for distributed generation and marine applications. In the program Wärtsilä focuses on system integration and development. System reliability and availability are key issues determining the competitiveness of the SOFC technology. In Wärtsilä, methods have been implemented for analysing the system in respect to reliability and safety as well as for defining reliability requirements for system components. A fault tree representation is used as the basis for reliability prediction analysis. A dynamic simulation technique has been developed to allow for non-static properties in the fault tree logic modelling. Special emphasis has been placed on reliability analysis of the fuel cell stacks in the system. A method for assessing reliability and critical failure predictability requirements for fuel cell stacks in a system consisting of several stacks has been developed. The method is based on a qualitative model of the stack configuration where each stack can be in a functional, partially failed or critically failed state, each of the states having different failure rates and effects on the system behaviour. The main purpose of the method is to understand the effect of stack reliability, critical failure predictability and operating strategy on the system reliability and availability. An example configuration, consisting of 5 × 5 stacks (series of 5 sets of 5 parallel stacks) is analysed in respect to stack reliability requirements as a function of predictability of critical failures and Weibull shape factor of failure rate distributions.

Development and preliminary experimental study on micro-stacked insulator

International Nuclear Information System (INIS)

Ren Chengyan; Yuan Weiqun; Zhang Dongdong; Yan Ping; Wang Jue

2009-01-01

High gradient insulating technology is one of the key technologies in new type dielectric wall accelerator(DWA). High gradient insulator, namely micro-stacked insulator, was developed and preliminary experimental study was done. Based on the finite element and particle simulating method, surface electric field distribution and electron movement track of micro-stacked insulator were numerated, and then the optimized design proposal was put forward. Using high temperature laminated method, we developed micro-stacked insulator samples which uses exhaustive fluorinated ethylene propylene(FEP) as dielectric layer and stainless steel as metal layer. Preliminary experiment of vacuum surface flashover in nanosecond pulse voltage was done and micro-stacked insulator exhibited favorable vacuum surface flashover performance with flashover field strength of near 180 kV/cm. (authors)

Stacking Defects in Synthetic and Meteoritic Hibonites: Implications for High-Temperature Processes in the Solar Nebula

Science.gov (United States)

Han, J.; Keller, L. P.; Brearley, A. J.; Danielson, L. R.

2016-01-01

Hibonite (CaAl12O19) is a primary, highly refractory phase occurring in many Ca-Al-rich inclusions (CAIs) from different chondrite groups, except CI chondrites. Hibonite is predicted to be one of the earliest minerals to condense during cooling of the solar nebula at higher temperatures than any other major CAI mineral. Therefore, hibonite has great potential to reveal the processes and conditions of the very early, high-temperature stages of the solar nebular evolution. Previous microstructural studies of hibonite in CAIs and their Wark-Lovering (WL) rims showed the presence of numerous stacking defects in hibonite. These defects are interpreted as the modification of the stacking sequences of spinel and Ca-containing blocks within the ideal hexagonal hibonite structure, as shown by experimental studies of reaction-sintered ceramic CaO-Al2O3 compounds. We performed preliminary experiments in the CaO-Al2O3-MgO system to understand the formation processes and conditions of defect-structured hibonite found in meteorites.

Protein Solvent-Accessibility Prediction by a Stacked Deep Bidirectional Recurrent Neural Network

Directory of Open Access Journals (Sweden)

Buzhong Zhang

2018-05-01

Full Text Available Residue solvent accessibility is closely related to the spatial arrangement and packing of residues. Predicting the solvent accessibility of a protein is an important step to understand its structure and function. In this work, we present a deep learning method to predict residue solvent accessibility, which is based on a stacked deep bidirectional recurrent neural network applied to sequence profiles. To capture more long-range sequence information, a merging operator was proposed when bidirectional information from hidden nodes was merged for outputs. Three types of merging operators were used in our improved model, with a long short-term memory network performing as a hidden computing node. The trained database was constructed from 7361 proteins extracted from the PISCES server using a cut-off of 25% sequence identity. Sequence-derived features including position-specific scoring matrix, physical properties, physicochemical characteristics, conservation score and protein coding were used to represent a residue. Using this method, predictive values of continuous relative solvent-accessible area were obtained, and then, these values were transformed into binary states with predefined thresholds. Our experimental results showed that our deep learning method improved prediction quality relative to current methods, with mean absolute error and Pearson’s correlation coefficient values of 8.8% and 74.8%, respectively, on the CB502 dataset and 8.2% and 78%, respectively, on the Manesh215 dataset.

Protein Solvent-Accessibility Prediction by a Stacked Deep Bidirectional Recurrent Neural Network.

Science.gov (United States)

Zhang, Buzhong; Li, Linqing; Lü, Qiang

2018-05-25

Residue solvent accessibility is closely related to the spatial arrangement and packing of residues. Predicting the solvent accessibility of a protein is an important step to understand its structure and function. In this work, we present a deep learning method to predict residue solvent accessibility, which is based on a stacked deep bidirectional recurrent neural network applied to sequence profiles. To capture more long-range sequence information, a merging operator was proposed when bidirectional information from hidden nodes was merged for outputs. Three types of merging operators were used in our improved model, with a long short-term memory network performing as a hidden computing node. The trained database was constructed from 7361 proteins extracted from the PISCES server using a cut-off of 25% sequence identity. Sequence-derived features including position-specific scoring matrix, physical properties, physicochemical characteristics, conservation score and protein coding were used to represent a residue. Using this method, predictive values of continuous relative solvent-accessible area were obtained, and then, these values were transformed into binary states with predefined thresholds. Our experimental results showed that our deep learning method improved prediction quality relative to current methods, with mean absolute error and Pearson's correlation coefficient values of 8.8% and 74.8%, respectively, on the CB502 dataset and 8.2% and 78%, respectively, on the Manesh215 dataset.

PRECISION COSMOGRAPHY WITH STACKED VOIDS

International Nuclear Information System (INIS)

Lavaux, Guilhem; Wandelt, Benjamin D.

2012-01-01

We present a purely geometrical method for probing the expansion history of the universe from the observation of the shape of stacked voids in spectroscopic redshift surveys. Our method is an Alcock-Paczyński (AP) test based on the average sphericity of voids posited on the local isotropy of the universe. It works by comparing the temporal extent of cosmic voids along the line of sight with their angular, spatial extent. We describe the algorithm that we use to detect and stack voids in redshift shells on the light cone and test it on mock light cones produced from N-body simulations. We establish a robust statistical model for estimating the average stretching of voids in redshift space and quantify the contamination by peculiar velocities. Finally, assuming that the void statistics that we derive from N-body simulations is preserved when considering galaxy surveys, we assess the capability of this approach to constrain dark energy parameters. We report this assessment in terms of the figure of merit (FoM) of the dark energy task force and in particular of the proposed Euclid mission which is particularly suited for this technique since it is a spectroscopic survey. The FoM due to stacked voids from the Euclid wide survey may double that of all other dark energy probes derived from Euclid data alone (combined with Planck priors). In particular, voids seem to outperform baryon acoustic oscillations by an order of magnitude. This result is consistent with simple estimates based on mode counting. The AP test based on stacked voids may be a significant addition to the portfolio of major dark energy probes and its potentialities must be studied in detail.

Effect of flow parameters on flare stack generator noise

International Nuclear Information System (INIS)

Dinn, T.S.

1998-01-01

The SoundPLAN Computer Noise Model was used to determine the general effect of flare noise in a community adjacent to a petrochemical plant. Tests were conducted to determine the effect of process flow conditions and the pulsating flame on the flare stack generator noise from both a refinery flare and process flare. Flaring under normal plant operations, the flaring of fuel gas and the flaring of hydrogen were the three conditions that were tested. It was shown that the steam flow rate was the determining factor in the flare stack generated noise. Variations in the water seal level in the flare line surge tank increased or decreased the gas flowrate, which resulted in a pulsating flame. The period and amplitude of the pulsating noise from the flare stacks was determined by measuring several parameters. Flare stack noise oscillations were found to be greater for the process flare than for the refinery flare stack. It was suggested that minimizing the amount of steam fed to the flare and improving the burner design would minimize noise. 2 tabs., 6 figs

Progress of MCFC stack technology at Toshiba

Energy Technology Data Exchange (ETDEWEB)

Hori, M.; Hayashi, T.; Shimizu, Y. [Toshiba Corp., Tokyo (Japan)

1996-12-31

Toshiba is working on the development of MCFC stack technology; improvement of cell characteristics, and establishment of separator technology. For the cell technology, Toshiba has concentrated on both the restraints of NiO cathode dissolution and electrolyte loss from cells, which are the critical issues to extend cell life in MCFC, and great progress has been made. On the other hand, recognizing that the separator is one of key elements in accomplishing reliable and cost-competitive MCFC stacks, Toshiba has been accelerating the technology establishment and verification of an advanced type separator. A sub-scale stack with such a separator was provided for an electric generating test, and has been operated for more than 10,000 hours. This paper presents several topics obtained through the technical activities in the MCFC field at Toshiba.

Calculation of tritium release from reactor's stack

International Nuclear Information System (INIS)

Akhadi, M.

1996-01-01

Method for calculation of tritium release from nuclear to environment has been discussed. Part of gas effluent contain tritium in form of HTO vapor released from reactor's stack was sampled using silica-gel. The silica-gel was put in the water to withdraw HTO vapor absorbed by silica-gel. Tritium concentration in the water was measured by liquid scintillation counter of Aloka LSC-703. Tritium concentration in the gas effluent and total release of tritium from reactor's stack during certain interval time were calculated using simple mathematic formula. This method has examined for calculation of tritium release from JRR-3M's stack of JAERI, Japan. From the calculation it was obtained the value of tritium release as much as 4.63 x 10 11 Bq during one month. (author)

Vertically stacked multi-heterostructures of layered materials for logic transistors and complementary inverters

Science.gov (United States)

Yu, Woo Jong; Li, Zheng; Zhou, Hailong; Chen, Yu; Wang, Yang; Huang, Yu; Duan, Xiangfeng

2014-01-01

The layered materials such as graphene have attracted considerable interest for future electronics. Here we report the vertical integration of multi-heterostructures of layered materials to enable high current density vertical field-effect transistors (VFETs). An n-channel VFET is created by sandwiching few-layer molybdenum disulfide (MoS2) as the semiconducting channel between a monolayer graphene and a metal thin film. The VFETs exhibit a room temperature on-off ratio >103, while at same time deliver a high current density up to 5,000 A/cm2, sufficient for high performance logic applications. This study offers a general strategy for the vertical integration of various layered materials to obtain both p- and n-channel transistors for complementary logic functions. A complementary inverter with larger than unit voltage gain is demonstrated by vertically stacking the layered materials of graphene, Bi2Sr2Co2O8 (p-channel), graphene, MoS2 (n-channel), and metal thin film in sequence. The ability to simultaneously achieve high on-off ratio, high current density, and logic integration in the vertically stacked multi-heterostructures can open up a new dimension for future electronics to enable three-dimensional integration. PMID:23241535

LAB3 Cosmic Ray Test Stand Analysis of Steel Stack Supports

International Nuclear Information System (INIS)

Cease, H.

1998-01-01

A cosmic ray test stand is being constructed at Lab 3. The stand consists of two stacks of steel plates one resting on top of the other. The top stack is composed of 6 plates of steel making an overall stack size of 34.5-inch x 40-inch x 99-inch. The bottom stack also has 6 layers of plate making an overall size of approximately 49.5-inch x 82-inch x 99-inch. The bottom stack is supported with three support legs. See drawing 3823.000ME-900428 for the individual plate orientation. The minimum support leg size and necessary welds between plates are determined.

Morphological spot counting from stacked images for automated analysis of gene copy numbers by fluorescence in situ hybridization.

Science.gov (United States)

Grigoryan, Artyom M; Dougherty, Edward R; Kononen, Juha; Bubendorf, Lukas; Hostetter, Galen; Kallioniemi, Olli

2002-01-01

Fluorescence in situ hybridization (FISH) is a molecular diagnostic technique in which a fluorescent labeled probe hybridizes to a target nucleotide sequence of deoxyribose nucleic acid. Upon excitation, each chromosome containing the target sequence produces a fluorescent signal (spot). Because fluorescent spot counting is tedious and often subjective, automated digital algorithms to count spots are desirable. New technology provides a stack of images on multiple focal planes throughout a tissue sample. Multiple-focal-plane imaging helps overcome the biases and imprecision inherent in single-focal-plane methods. This paper proposes an algorithm for global spot counting in stacked three-dimensional slice FISH images without the necessity of nuclei segmentation. It is designed to work in complex backgrounds, when there are agglomerated nuclei, and in the presence of illumination gradients. It is based on the morphological top-hat transform, which locates intensity spikes on irregular backgrounds. After finding signals in the slice images, the algorithm groups these together to form three-dimensional spots. Filters are employed to separate legitimate spots from fluorescent noise. The algorithm is set in a comprehensive toolbox that provides visualization and analytic facilities. It includes simulation software that allows examination of algorithm performance for various image and algorithm parameter settings, including signal size, signal density, and the number of slices.

FocusStack and StimServer: a new open source MATLAB toolchain for visual stimulation and analysis of two-photon calcium neuronal imaging data.

Science.gov (United States)

Muir, Dylan R; Kampa, Björn M

2014-01-01

Two-photon calcium imaging of neuronal responses is an increasingly accessible technology for probing population responses in cortex at single cell resolution, and with reasonable and improving temporal resolution. However, analysis of two-photon data is usually performed using ad-hoc solutions. To date, no publicly available software exists for straightforward analysis of stimulus-triggered two-photon imaging experiments. In addition, the increasing data rates of two-photon acquisition systems imply increasing cost of computing hardware required for in-memory analysis. Here we present a Matlab toolbox, FocusStack, for simple and efficient analysis of two-photon calcium imaging stacks on consumer-level hardware, with minimal memory footprint. We also present a Matlab toolbox, StimServer, for generation and sequencing of visual stimuli, designed to be triggered over a network link from a two-photon acquisition system. FocusStack is compatible out of the box with several existing two-photon acquisition systems, and is simple to adapt to arbitrary binary file formats. Analysis tools such as stack alignment for movement correction, automated cell detection and peri-stimulus time histograms are already provided, and further tools can be easily incorporated. Both packages are available as publicly-accessible source-code repositories.

Aimed manipulation of fluxon dynamics in stacks of intrinsic Josephson-junctions out of Bi2Sr2CaCu2O8+x

International Nuclear Information System (INIS)

Oehmichen, V.

2007-01-01

Goal of this thesis was to extend the knowledge of fluxon dynamics in intrinsic Josephson junctions out of BSCCO and to manipulate this dynamics in a purposeful way. New approaches to create ThZ-radiation were investigated. Step stacks out of BSCCO have been prepared with dimensions of 1-3 μm (width) and 3-10 μm (length). The necessary fabrication process was established based on Wang's double-sided technique. Transport measurements without and with magnetic field were realised on the so produced samples. The magnetic field of some Tesla was oriented parallel to the CuO 2 -double layers. Collective plasma resonances were observed. Those were more stable than the resonances in mesa-structures. The resonances in the low current range can be assigned to an out-of-phase configuration, whereas in the high current range there are some possible configurations. Flux-flow-oscillations measured at these step stacks support the arrangement of the fluxons in an out-of-phase configuration. The in-phase configuration couldn't be observed clearly, so two approaches were followed to manipulate aimingly the fluxon dynamics to create THz-radiation: * control current * geometric manipulation: width-modulated stack For electronic manipulation an additional current line (control current line) was prepared along the stack's bottom. During transport measurements in zero field a current of 0-30 μA was sent through this control current line. The so created inhomogeneity should have provoked fluxons without the help of a magnetic field. A visible effect couldn't be measured. Geometric manipulation of fluxon dynamics to reach in-phase configuration relys on modulation of the stack's width: it has periodic necks (comb structure). First measurements on comb structures prepared in double-side technique show promising hints, that manipulation on purpose of fluxon dynamics is possible using width-modulation. Simulations were performed for different depths of modulation, small and large stacks

Nonlinearly stacked low noise turbofan stator

Science.gov (United States)

Schuster, William B. (Inventor); Nolcheff, Nick A. (Inventor); Gunaraj, John A. (Inventor); Kontos, Karen B. (Inventor); Weir, Donald S. (Inventor)

2009-01-01

A nonlinearly stacked low noise turbofan stator vane having a characteristic curve that is characterized by a nonlinear sweep and a nonlinear lean is provided. The stator is in an axial fan or compressor turbomachinery stage that is comprised of a collection of vanes whose highly three-dimensional shape is selected to reduce rotor-stator and rotor-strut interaction noise while maintaining the aerodynamic and mechanical performance of the vane. The nonlinearly stacked low noise turbofan stator vane reduces noise associated with the fan stage of turbomachinery to improve environmental compatibility.

Structure of a filament of stacked octamers of human DMC1 recombinase

International Nuclear Information System (INIS)

Du, Liqin; Luo, Yu

2013-01-01

Octameric rings of DMC1 stacked into filaments in the crystal. Similar DMC1–DNA filaments have been observed previously using electron microscopy. Eukaryal DMC1 proteins play a central role in homologous recombination in meiosis by assembling at the sites of programmed DNA double-strand breaks and carrying out a search for allelic DNA sequences located on homologous chromatids. They are close homologs of eukaryal Rad51 and archaeal RadA proteins and are remote homologs of bacterial RecA proteins. These recombinases (also called DNA strand-exchange proteins) promote a pivotal strand-exchange reaction between homologous single-stranded and double-stranded DNA substrates. An octameric form of a truncated human DMC1 devoid of its small N-terminal domain (residues 1–83) has been crystallized. The structure of the truncated DMC1 octamer is similar to that of the previously reported full-length DMC1 octamer, which has disordered N-terminal domains. In each protomer, only the ATP cap regions (Asp317–Glu323) show a noticeable conformational difference. The truncated DMC1 octamers further stack with alternate polarity into a filament. Similar filamentous assemblies of DMC1 have been observed to form on DNA by electron microscopy

Effect of stacking faults on the magnetocrystalline anisotropy of hcp Co-based nanowires

Energy Technology Data Exchange (ETDEWEB)

Kha, Tuan Mai; Schoenstein, Frédéric; Zighem, Fatih [Laboratoire des Sciences des Procédés et des Matériaux (LSPM-UPR3407), CNRS-Université Paris XIII, Sorbonne Paris Cité, Villetaneuse (France); Nowak, Sophie [Université Paris Diderot, Sorbonne Paris Cité, ITODYS, CNRS UMR 7086, 15 rue J.-A. de Baïf, 75205 Paris Cedex 13 (France); Leridon, Brigitte [LPEM, ESPCI Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC, F-75005 Paris (France); Jouini, Noureddine [Laboratoire des Sciences des Procédés et des Matériaux (LSPM-UPR3407), CNRS-Université Paris XIII, Sorbonne Paris Cité, Villetaneuse (France); Mercone, Silvana, E-mail: silvana.mercone@univ-paris13.fr [Laboratoire des Sciences des Procédés et des Matériaux (LSPM-UPR3407), CNRS-Université Paris XIII, Sorbonne Paris Cité, Villetaneuse (France)

2017-01-15

Replacing materials based on rare-earth elements in current permanent magnets is a real scientific, economic and environmental challenge. Ferromagnetic 3d transition metals seem an apt direction to go in this field, due to their high residual magnetization and thermal stability. In order to improve their coercive behavior, nanostructured magnets based on the assembly of high-aspect-ratio nanoparticles (i.e. cobalt based nanorods and nanowires) have recently been proposed. In these, the nanoparticle morphology itself drives the magnetization reversal mechanism. This purely geometrical effect seems to obscure the effects of structural defects, although it is clear that high magnetocrystalline energy is required to maintain a stable orientation of the magnetic moment inside the nanoparticles. We present here an experimental study whose aim is to distinguish the role of the stacking faults from the effects of shape and morphology on the magnetization reversal mechanism in cobalt-based nanowires. Coercive field results have been obtained on Co{sub 80}Ni{sub 20} nanowires synthesized by a polyol process. Through accurate control of shape and morphology, it was possible to discard the effects of shape and thus to highlight the influence of crystal defects on the magnetism of Co{sub 80}Ni{sub 20} nanowires. A micromagnetic study, consistent with the experimental analyses, is also presented. The results discussed in this work clearly show that even if the morphological characteristics are conducive to a high coercive field, the presence of numerous stacking faults has the opposite effect and leads to materials with a significantly lower coercive field than expected, which is not suitable for permanent magnet applications. - Highlights: • Optimization of the nanowires magnetic properties for permanent magnet applications. • Magnetization reversal mechanism study as function of the shape, structural and chemical homogeneity. • Effect of stacking faults on the coercive

Analysis of preemption costs for the stack cache

DEFF Research Database (Denmark)

Naji, Amine; Abbaspour, Sahar; Brandner, Florian

2018-01-01

, the analysis of the stack cache was limited to individual tasks, ignoring aspects related to multitasking. A major drawback of the original stack cache design is that, due to its simplicity, it cannot hold the data of multiple tasks at the same time. Consequently, the entire cache content needs to be saved...

A stacking method and its applications to Lanzarote tide gauge records

Science.gov (United States)

Zhu, Ping; van Ruymbeke, Michel; Cadicheanu, Nicoleta

2009-12-01

A time-period analysis tool based on stacking is introduced in this paper. The original idea comes from the classical tidal analysis method. It is assumed that the period of each major tidal component is precisely determined based on the astronomical constants and it is unchangeable with time at a given point in the Earth. We sum the tidal records at a fixed tidal component center period T then take the mean of it. The stacking could significantly increase the signal-to-noise ratio (SNR) if a certain number of stacking circles is reached. The stacking results were fitted using a sinusoidal function, the amplitude and phase of the fitting curve is computed by the least squares methods. The advantage of the method is that: (1) an individual periodical signal could be isolated by stacking; (2) one can construct a linear Stacking-Spectrum (SSP) by changing the stacking period Ts; (3) the time-period distribution of the singularity component could be approximated by a Sliding-Stacking approach. The shortcoming of the method is that in order to isolate a low energy frequency or separate the nearby frequencies, we need a long enough series with high sampling rate. The method was tested with a numeric series and then it was applied to 1788 days Lanzarote tide gauge records as an example.

Relative stabilities and the spectral signatures of stacked and hydrogen-bonded dimers of serotonin

Science.gov (United States)

Dev, S.; Giri, K.; Majumder, M.; Sathyamurthy, N.

2015-10-01

The O-HṡṡṡN hydrogen-bonded dimer of serotonin is shown to be more stable than the stacked dimer in its ground electronic state, by using the Møller-Plesset second-order perturbation theory (MP2) and the 6-31g** basis set. The vertical excitation energy for the lowest π → π* transition for the monomer as well as the dimer is predicted by time-dependent density functional theory. The experimentally observed red shift of excitation wavelength on oligomerisation is explained in terms of the change in the HOMO-LUMO energy gap due to complex formation. The impact of dimer formation on the proton magnetic resonance spectrum of serotonin monomer is also examined.

Stacking fault density and bond orientational order of fcc ruthenium nanoparticles

Science.gov (United States)

Seo, Okkyun; Sakata, Osami; Kim, Jae Myung; Hiroi, Satoshi; Song, Chulho; Kumara, Loku Singgappulige Rosantha; Ohara, Koji; Dekura, Shun; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi

2017-12-01

We investigated crystal structure deviations of catalytic nanoparticles (NPs) using synchrotron powder X-ray diffraction. The samples were fcc ruthenium (Ru) NPs with diameters of 2.4, 3.5, 3.9, and 5.4 nm. We analyzed average crystal structures by applying the line profile method to a stacking fault model and local crystal structures using bond orientational order (BOO) parameters. The reflection peaks shifted depending on rules that apply to each stacking fault. We evaluated the quantitative stacking faults densities for fcc Ru NPs, and the stacking fault per number of layers was 2-4, which is quite large. Our analysis shows that the fcc Ru 2.4 nm-diameter NPs have a considerably high stacking fault density. The B factor tends to increase with the increasing stacking fault density. A structural parameter that we define from the BOO parameters exhibits a significant difference from the ideal value of the fcc structure. This indicates that the fcc Ru NPs are highly disordered.

Generalized diffraction-stack migration and filtering of coherent noise

KAUST Repository

Zhan, Ge

2014-01-27

We reformulate the equation of reverse-time migration so that it can be interpreted as summing data along a series of hyperbola-like curves, each one representing a different type of event such as a reflection or multiple. This is a generalization of the familiar diffraction-stack migration algorithm where the migration image at a point is computed by the sum of trace amplitudes along an appropriate hyperbola-like curve. Instead of summing along the curve associated with the primary reflection, the sum is over all scattering events and so this method is named generalized diffraction-stack migration. This formulation leads to filters that can be applied to the generalized diffraction-stack migration operator to mitigate coherent migration artefacts due to, e.g., crosstalk and aliasing. Results with both synthetic and field data show that generalized diffraction-stack migration images have fewer artefacts than those computed by the standard reverse-time migration algorithm. The main drawback is that generalized diffraction-stack migration is much more memory intensive and I/O limited than the standard reverse-time migration method. © 2014 European Association of Geoscientists & Engineers.

Mixed Mechanism of Lubrication by Lipid Bilayer Stacks.

Science.gov (United States)

Boţan, Alexandru; Joly, Laurent; Fillot, Nicolas; Loison, Claire

2015-11-10

Although the key role of lipid bilayer stacks in biological lubrication is generally accepted, the mechanisms underlying their extreme efficiency remain elusive. In this article, we report molecular dynamics simulations of lipid bilayer stacks undergoing load and shear. When the hydration level is reduced, the velocity accommodation mechanism changes from viscous shear in hydration water to interlayer sliding in the bilayers. This enables stacks of hydrated lipid bilayers to act as efficient boundary lubricants for various hydration conditions, structures, and mechanical loads. We also propose an estimation for the friction coefficient; thanks to the strong hydration forces between lipid bilayers, the high local viscosity is not in contradiction with low friction coefficients.

Stacking and discontinuous buffers in capillary zone electrophoresis.

Science.gov (United States)

Shihabi, Z K

2000-08-01

Discontinuous buffers for capillary zone electrophoresis (CZE) can be used under less rigid conditions compared to those for isotachophoresis for stacking. They can be prepared simply by modifying the sample itself, either by addition of small inorganic ions, low conductivity diluents, or both, and also by adjusting its pH, meanwhile injecting a large volume on the capillary. Zwitterionic and organic-based buffers such as triethanolamine and tris(hydroxymethyl)aminomethane (Tris) are well suited for stacking due to their low conductivity, provided the buffer is discontinuous as demonstrated here. A simple mechanism based on discontinuous buffers is described to explain many of the observed stacking types in CZE, pointing out the many similarities to transient isotachophoresis.

Ablation of film stacks in solar cell fabrication processes

Science.gov (United States)

Harley, Gabriel; Kim, Taeseok; Cousins, Peter John

2013-04-02

A dielectric film stack of a solar cell is ablated using a laser. The dielectric film stack includes a layer that is absorptive in a wavelength of operation of the laser source. The laser source, which fires laser pulses at a pulse repetition rate, is configured to ablate the film stack to expose an underlying layer of material. The laser source may be configured to fire a burst of two laser pulses or a single temporally asymmetric laser pulse within a single pulse repetition to achieve complete ablation in a single step.

Stacking-dependent electronic property of trilayer graphene epitaxially grown on Ru(0001)

Energy Technology Data Exchange (ETDEWEB)

Que, Yande; Xiao, Wende, E-mail: wdxiao@iphy.ac.cn, E-mail: hjgao@iphy.ac.cn; Chen, Hui; Wang, Dongfei; Du, Shixuan; Gao, Hong-Jun, E-mail: wdxiao@iphy.ac.cn, E-mail: hjgao@iphy.ac.cn [Institute of Physics and University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100190 (China)

2015-12-28

The growth, atomic structure, and electronic property of trilayer graphene (TLG) on Ru(0001) were studied by low temperature scanning tunneling microscopy and spectroscopy in combined with tight-binding approximation (TBA) calculations. TLG on Ru(0001) shows a flat surface with a hexagonal lattice due to the screening effect of the bottom two layers and the AB-stacking in the top two layers. The coexistence of AA- and AB-stacking in the bottom two layers leads to three different stacking orders of TLG, namely, ABA-, ABC-, and ABB-stacking. STS measurements combined with TBA calculations reveal that the density of states of TLG with ABC- and ABB-stacking is characterized by one and two sharp peaks near to the Fermi level, respectively, in contrast to the V-shaped feature of TLG with ABA-stacking. Our work demonstrates that TLG on Ru(0001) might be an ideal platform for exploring stacking-dependent electronic properties of graphene.

Design and analysis of the PBFA-Z vacuum insulator stack

International Nuclear Information System (INIS)

Shoup, R.W.; Long, F.; Martin, T.H.; Stygar, W.A.; Spielman, R.B.; Struve, K.W.; Mostrom, M.; Corcoran, P.; Smith, I.

1996-01-01

Sandia is developing PBFA-Z, a 20-MA driver for z-pinch experiments by replacing the water lines, insulator stack, and MITLs on PBFA II with new hardware. The design of the vacuum insulator stack was dictated by the drive voltage, the electric field stress and grading requirements, the water line and MITL interface requirements, and the machine operations and maintenance requirements. The insulator stack will consist of four separate modules, each of a different design because of different voltage drive and hardware interface requirements. The shape of the components in each module, i.e., grading rings, insulator rings, flux excluders, anode and cathode conductors, and the design of the water line and MITL interfaces, were optimized by using the electrostatic analysis codes, ELECTRO and JASON. The time-dependent performance of the insulator stack was evaluated using IVORY, a 2-D PIC code. The insulator stack design and present the results of the ELECTRO and IVORY analyses are described. (author). 2 tabs., 9 figs., 3 refs

Design and analysis of the PBFA-Z vacuum insulator stack

Energy Technology Data Exchange (ETDEWEB)

Shoup, R W [Field Command Defense Nuclear Agency, Kirtland AFB, NM (United States); Long, F; Martin, T H; Stygar, W A; Spielman, R B [Sandia National Laboratories, Albuquerque, NM (United States). Dept 9573; Ives, H [EG and G, Albuquerque, NM (United States); Struve, K W; Mostrom, M [Mission Research Corp., Albuquerque, NM (United States); Corcoran, P; Smith, I [Pulse Sciences, Inc., San Leandro, CA (United States)

1997-12-31

Sandia is developing PBFA-Z, a 20-MA driver for z-pinch experiments by replacing the water lines, insulator stack, and MITLs on PBFA II with new hardware. The design of the vacuum insulator stack was dictated by the drive voltage, the electric field stress and grading requirements, the water line and MITL interface requirements, and the machine operations and maintenance requirements. The insulator stack will consist of four separate modules, each of a different design because of different voltage drive and hardware interface requirements. The shape of the components in each module, i.e., grading rings, insulator rings, flux excluders, anode and cathode conductors, and the design of the water line and MITL interfaces, were optimized by using the electrostatic analysis codes, ELECTRO and JASON. The time-dependent performance of the insulator stack was evaluated using IVORY, a 2-D PIC code. The insulator stack design and present the results of the ELECTRO and IVORY analyses are described. (author). 2 tabs., 9 figs., 3 refs.

Long Josephson Junction Stack Coupled to a Cavity

DEFF Research Database (Denmark)

Madsen, Søren Peder; Pedersen, Niels Falsig; Groenbech-Jensen, N.

2007-01-01

A stack of inductively coupled long Josephson junctions are modeled as a system of coupled sine-Gordon equations. One boundary of the stack is coupled electrically to a resonant cavity. With one fluxon in each Josephson junction, the inter-junction fluxon forces are repulsive. We look at a possible...... transition, induced by the cavity, to a bunched state....

Asymmetric Flexible Supercapacitor Stack

Directory of Open Access Journals (Sweden)

Leela Mohana Reddy A

2008-01-01

Full Text Available AbstractElectrical double layer supercapacitor is very significant in the field of electrical energy storage which can be the solution for the current revolution in the electronic devices like mobile phones, camera flashes which needs flexible and miniaturized energy storage device with all non-aqueous components. The multiwalled carbon nanotubes (MWNTs have been synthesized by catalytic chemical vapor deposition technique over hydrogen decrepitated Mischmetal (Mm based AB3alloy hydride. The polymer dispersed MWNTs have been obtained by insitu polymerization and the metal oxide/MWNTs were synthesized by sol-gel method. Morphological characterizations of polymer dispersed MWNTs have been carried out using scanning electron microscopy (SEM, transmission electron microscopy (TEM and HRTEM. An assymetric double supercapacitor stack has been fabricated using polymer/MWNTs and metal oxide/MWNTs coated over flexible carbon fabric as electrodes and nafion®membrane as a solid electrolyte. Electrochemical performance of the supercapacitor stack has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

Electronic structure of the rotation twin stacking fault in β-ZnS

International Nuclear Information System (INIS)

Northrup, J.E.; Cohen, M.L.

1981-01-01

The electronic structure of the rotation twin stacking fault in β-ZnS is calculated with the self-consistent pseudopotential method. The stacking fault creates a potential barrier of approx.0.07 eV and induces the localization of stacking-fault resonances near the top of the valence band. Stacking-fault states are also predicted to exist in the various gaps in the projected valence-band structure

Simulation of magnetization and levitation characteristics of HTS tape stacks

Science.gov (United States)

Anischenko, I. V.; Pokrovskii, S. V.; Mineev, N. A.

2017-12-01

In this work it is presented a computational model of a magnetic levitation system based on stacks of high-temperature second generation superconducting tapes (HTS) GdBa2Cu3O7-x. Calculated magnetic field and the current distributions in the system for different stacks geometries in the zero-field cooling mode are also presented. The magnetization curves of the stacks in the external field of a permanent NdFeB magnet and the levitation force dependence on the gap between the magnet and the HTS tapes stack were obtained. A model of the magnetic system, oriented to levitation application, is given. Results of modeling were compared with the experimental data.

Stack Flow Rate Changes and the ANSI/N13.1-1999 Qualification Criteria: Application to the Hanford Canister Storage Building Stack

Energy Technology Data Exchange (ETDEWEB)

Flaherty, Julia E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Glissmeyer, John A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2016-02-29

The Canister Storage Building (CSB), located in the 200-East Area of the Hanford Site, is a 42,000 square foot facility used to store spent nuclear fuel from past activities at the Hanford Site. Because the facility has the potential to emit radionuclides into the environment, its ventilation exhaust stack has been equipped with an air monitoring system. Subpart H of the National Emissions Standards for Hazardous Air Pollutants requires that a sampling probe be located in the exhaust stack in accordance with criteria established by the American National Standards Institute/Health Physics Society Standard N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stack and Ducts of Nuclear Facilities.

High power, repetitive stacked Blumlein pulse generators

Energy Technology Data Exchange (ETDEWEB)

Davanloo, F; Borovina, D L; Korioth, J L; Krause, R K; Collins, C B [Univ. of Texas at Dallas, Richardson, TX (United States). Center for Quantum Electronics; Agee, F J [US Air Force Phillips Lab., Kirtland AFB, NM (United States); Kingsley, L E [US Army CECOM, Ft. Monmouth, NJ (United States)

1997-12-31

The repetitive stacked Blumlein pulse power generators developed at the University of Texas at Dallas consist of several triaxial Blumleins stacked in series at one end. The lines are charged in parallel and synchronously commuted with a single switch at the other end. In this way, relatively low charging voltages are multiplied to give a high discharge voltage across an arbitrary load. Extensive characterization of these novel pulsers have been performed over the past few years. Results indicate that they are capable of producing high power waveforms with rise times and repetition rates in the range of 0.5-50 ns and 1-300 Hz, respectively, using a conventional thyratron, spark gap, or photoconductive switch. The progress in the development and use of stacked Blumlein pulse generators is reviewed. The technology and the characteristics of these novel pulsers driving flash x-ray diodes are discussed. (author). 4 figs., 5 refs.

Measurements of proton energy spectra using a radiochromic film stack

Science.gov (United States)

Filkins, T. M.; Steidle, Jessica; Ellison, D. M.; Steidle, Jeffrey; Freeman, C. G.; Padalino, S. J.; Fiksel, G.; Regan, S. P.; Sangster, T. C.

2014-10-01

The energy spectrum of protons accelerated from the rear-side of a thin foil illuminated with ultra-intense laser light from the OMEGA EP laser system at the University of Rochester's Laboratory for Laser Energetics (LLE) was measured using a stack of radiochromic film (RCF). The film stack consisted of four layers of Gafchromic HD-V2 film and four layers of Gafchromic MD-V2-55 film. Aluminum foils of various thicknesses were placed between each piece of RCF in the stack. This arrangement allowed protons with energies of 30 MeV to reach the back layer of RCF in the stack. The stack was placed in the detector plane of a Thomson parabola ion energy (TPIE) spectrometer. Each piece of film in the stack was scanned using a commercially available flat-bed scanner (Epson 10000XL). The resulting optical density was converted into proton fluence using an absolute calibration of the RCF obtained at the SUNY Geneseo 1.7 MV Pelletron accelerator laboratory. In these calibration measurements, the sensitivity of the radiochromic film was measured using monoenergetic protons produced by the accelerator. Details of the analysis procedure and the resulting proton energy spectra will be presented. Funded in part by a grant from the DOE through the Laboratory for Laser Energetics.

Simulations Of Transverse Stacking In The NSLS-II Booster

International Nuclear Information System (INIS)

Fliller, R. III; Shaftan, T.

2011-01-01

The NSLS-II injection system consists of a 200 MeV linac and a 3 GeV booster. The linac needs to deliver 15 nC in 80 - 150 bunches to the booster every minute to achieve current stability goals in the storage ring. This is a very stringent requirement that has not been demonstrated at an operating light source. We have developed a scheme to transversely stack two bunch trains in the NSLS-II booster in order to alleviate the charge requirements on the linac. This scheme has been outlined previously. In this paper we show particle tracking simulations of the tracking scheme. We show simulations of the booster ramp with a stacked beam for a variety of lattice errors and injected beam parameters. In all cases the performance of the proposed stacking method is sufficient to reduce the required charge from the linac. For this reason the injection system of the NSLS-II booster is being designed to include this feature. The NSLS-II injection system consists of a 200 MeV linac and a 3 GeV booster. The injectors must provide 7.5nC in bunch trains 80-150 bunches long every minute for top off operation of the storage ring. Top off then requires that the linac deliver 15nC of charge once losses in the injector chain are taken into consideration. This is a very stringent requirement that has not been demonstrated at an operating light source. For this reason we have developed a method to transversely stack two bunch trains in the booster while maintaining the charge transport efficiency. This stacking scheme has been discussed previously. In this paper we show the simulations of the booster ramp with a single bunch train in the booster. Then we give a brief overview of the stacking scheme. Following, we show the results of stacking two bunch trains in the booster with varying beam emittances and train separations. The behavior of the beam through the ramp is examined showing that it is possible to stack two bunch trains in the booster.

Simulation and Optimization of Air-Cooled PEMFC Stack for Lightweight Hybrid Vehicle Application

Directory of Open Access Journals (Sweden)

Jingming Liang

2015-01-01

Full Text Available A model of 2 kW air-cooled proton exchange membrane fuel cell (PEMFC stack has been built based upon the application of lightweight hybrid vehicle after analyzing the characteristics of heat transfer of the air-cooled stack. Different dissipating models of the air-cooled stack have been simulated and an optimal simulation model for air-cooled stack called convection heat transfer (CHT model has been figured out by applying the computational fluid dynamics (CFD software, based on which, the structure of the air-cooled stack has been optimized by adding irregular cooling fins at the end of the stack. According to the simulation result, the temperature of the stack has been equally distributed, reducing the cooling density and saving energy. Finally, the 2 kW hydrogen-air air-cooled PEMFC stack is manufactured and tested by comparing the simulation data which is to find out its operating regulations in order to further optimize its structure.

Project W-420 Stack Monitoring system upgrades conceptual design report

International Nuclear Information System (INIS)

TUCK, J.A.

1998-01-01

This document describes the scope, justification, conceptual design, and performance of Project W-420 stack monitoring system upgrades on six NESHAP-designated, Hanford Tank Farms ventilation exhaust stacks

Project W-420 Stack Monitoring system upgrades conceptual design report

Energy Technology Data Exchange (ETDEWEB)

TUCK, J.A.

1998-11-06

This document describes the scope, justification, conceptual design, and performance of Project W-420 stack monitoring system upgrades on six NESHAP-designated, Hanford Tank Farms ventilation exhaust stacks.

Behavior of a nuclear power plant ventilation stack for wind loads

International Nuclear Information System (INIS)

Venkatachalapathy, V.

2012-01-01

This paper describes behavior of self supporting tall reinforced concrete (RC) ventilation stack of a nuclear power plant (NPP) for wind loads. Since the static and equivalent dynamic wind loads are inter-dependant on overall size of the stack, proper sizing of the stack geometry is important for reducing wind loads. The present study investigated the influence of engineered backfill soil on lateral response of ventilation stack. Ignoring backfill soil stiffness up to ground height does not allow to predict actual critical wind velocity causing across wind oscillation. The results show that proposed modification in the stack geometry modeled using 2D beam-spring elements is economical than that of single tapered geometry. Shaft diameter reduced in the proposed geometry indicates that there is a scope for overall space savings in the NPP layout. (author)

Technology leadership : a road map to commercially viable PEMFC stack technology

Energy Technology Data Exchange (ETDEWEB)

Stone, C. [Ballard Power Systems, Burnaby, BC (Canada)

2005-07-01

This abstract discussed recent advances in stack technology by Ballard Power Systems. The technology department of this Canadian-owned company exhibited the capability of a single proton exchange membrane fuel cell (PEMFC) stack design to demonstrate that cost reduction, freeze start capability from -20 degrees C and durability under an automotive dynamic operating cycle are comparable to that experienced by a fuel cell stack in an actual vehicle. A technology road map has been developed by the company to define a path to the commercial viability of the PEMFC stack by 2010. Key target parameters for cost reduction, durability, freeze start and stack power density were described in detail along with demonstrated historical capability and details of how the company will achieve its required targets. refs., tabs., figs.

Sequence Similarity Presenter: a tool for the graphic display of similarities of long sequences for use in presentations.

Science.gov (United States)

Fröhlich, K U

1994-04-01

A new method for the presentation of alignments of long sequences is described. The degree of identity for the aligned sequences is averaged for sections of a fixed number of residues. The resulting values are converted to shades of gray, with white corresponding to lack of identity and black corresponding to perfect identity. A sequence alignment is represented as a bar filled with varying shades of gray. The display is compact and allows for a fast and intuitive recognition of the distribution of regions with a high similarity. It is well suited for the presentation of alignments of long sequences, e.g. of protein superfamilies, in plenary lectures. The method is implemented as a HyperCard stack for Apple Macintosh computers. Several options for the modification of the output are available (e.g. background reduction, size of the summation window, consideration of amino acid similarity, inclusion of graphic markers to indicate specific domains). The output is a PostScript file which can be printed, imported as EPS or processed further with Adobe Illustrator.

Inter-layered clay stacks in Jurassic shales

Science.gov (United States)

Pye, K.; Krinsley, D. H.

1983-01-01

Scanning electron microscopy in the backscattered electron mode is used together with energy-dispersive X-ray microanalysis to show that Lower Jurassic shales from the North Sea Basin contain large numbers of clay mineral stacks up to 150 microns in size. Polished shale sections are examined to determine the size, shape orientation, textural relationships, and internal compositional variations of the clays. Preliminary evidence that the clay stacks are authigenic, and may have formed at shallow burial depths during early diagenesis, is presented.

Numerical Study on the Cooling Characteristics of a Passive-Type PEMFC Stack

International Nuclear Information System (INIS)

Lee, Jae Hyuk; Kim, Bo Sung; Lee, Yong Taek; Kim, Yong Chan

2010-01-01

In a passive-type PEMFC stack, axial fans operate to supply both oxidant and coolant to cathode side of the stack. It is possible to make a simple system because the passive-type PEMFC stack does not require additional cooling equipment. However, the performance of a cooling system in which water is used as a coolant is better than that of the air-cooling system. To ensure system reliability, it is essential to make cooling system effective by adopting an optimal stack design. In this study, a numerical investigation has been carried out to identify an optimum cooling strategy. Various channel configurations were applied to the test section. The passive-type PEMFC was tested by varying airflow rate distribution at the cathode side and external heat transfer coefficient of the stack. The best cooling performance was achieved when a channel with thick ribs was used, and the overheating at the center of the stack was reduced when a case in which airflow was concentrated at the middle of the stack was used

Multibands tunneling in AAA-stacked trilayer graphene

Science.gov (United States)

Redouani, Ilham; Jellal, Ahmed; Bahaoui, Abdelhadi; Bahlouli, Hocine

2018-04-01

We study the electronic transport through np and npn junctions for AAA-stacked trilayer graphene. Two kinds of gates are considered where the first is a single gate and the second is a double gate. After obtaining the solutions for the energy spectrum, we use the transfer matrix method to determine the three transmission probabilities for each individual cone τ = 0 , ± 1 . We show that the quasiparticles in AAA-stacked trilayer graphene are not only chiral but also labeled by an additional cone index τ. The obtained bands are composed of three Dirac cones that depend on the chirality indexes. We show that there is perfect transmission for normal or near normal incidence, which is a manifestation of the Klein tunneling effect. We analyze also the corresponding total conductance, which is defined as the sum of the conductance channels in each individual cone. Our results are numerically discussed and compared with those obtained for ABA- and ABC-stacked trilayer graphene.

A dual shared stack for FSLM in Erika Enterprise

NARCIS (Netherlands)

Balasubramanian, S.M.N.; Afshar, S.; Gai, P.; Behnam, M.; Bril, R.J.

2017-01-01

Recently, the flexible spin-lock model (FSLM) has been introduced, unifying spin-based and suspension-based resource sharing protocols for real-time multi-core platforms. Unlike the multiprocessor stack resource policy (MSRP), FSLM doesn’t allow tasks on a core to share a single stack, however. In

A Software Managed Stack Cache for Real-Time Systems

DEFF Research Database (Denmark)

Jordan, Alexander; Abbaspourseyedi, Sahar; Schoeberl, Martin

2016-01-01

In a real-time system, the use of a scratchpad memory can mitigate the difficulties related to analyzing data caches, whose behavior is inherently hard to predict. We propose to use a scratchpad memory for stack allocated data. While statically allocating stack frames for individual functions...

Radiation-Tolerant Intelligent Memory Stack - RTIMS

Science.gov (United States)

Ng, Tak-kwong; Herath, Jeffrey A.

2011-01-01

This innovation provides reconfigurable circuitry and 2-Gb of error-corrected or 1-Gb of triple-redundant digital memory in a small package. RTIMS uses circuit stacking of heterogeneous components and radiation shielding technologies. A reprogrammable field-programmable gate array (FPGA), six synchronous dynamic random access memories, linear regulator, and the radiation mitigation circuits are stacked into a module of 42.7 42.7 13 mm. Triple module redundancy, current limiting, configuration scrubbing, and single- event function interrupt detection are employed to mitigate radiation effects. The novel self-scrubbing and single event functional interrupt (SEFI) detection allows a relatively soft FPGA to become radiation tolerant without external scrubbing and monitoring hardware

On some topological properties of stable measures

DEFF Research Database (Denmark)

Nielsen, Carsten Krabbe

1996-01-01

Summary The paper shows that the set of stable probability measures and the set of Rational Beliefs relative to a given stationary measure are closed in the strong topology, but not closed in the topology of weak convergence. However, subsets of the set of stable probability measures which...... are characterized by uniformity of convergence of the empirical distribution are closed in the topology of weak convergence. It is demonstrated that such subsets exist. In particular, there is an increasing sequence of sets of SIDS measures who's union is the set of all SIDS measures generated by a particular...... system and such that each subset consists of stable measures. The uniformity requirement has a natural interpretation in terms of plausibility of Rational Beliefs...

Effects of heating on composition, degree of darkness, and stacking nanostructure of soil humic acids

Energy Technology Data Exchange (ETDEWEB)

Katsumi, Naoya, E-mail: n-katsu@ishikawa-pu.ac.jp; Yonebayashi, Koyo; Okazaki, Masanori

2016-01-15

Wildfires and prescribed burning can affect both the quality and the quantity of organic matter in soils. In this study, we investigated qualitative and quantitative changes of soil humic substances in two different soils (an Entisol from a paddy field and an Inceptisol from a cedar forest) under several controlled heating conditions. Soil samples were heated in a muffle furnace at 200, 250, or 300 °C for 1, 3, 5, or 12 h. The humic acid and fulvic acid contents of the soil samples prior to and after heating were determined. The degree of darkness, elemental composition, carbon and nitrogen stable isotope ratios, {sup 13}C nuclear magnetic resonance spectra, and X-ray diffraction patterns of humic acids extracted from the soils before and after heating were measured. The proportion of humic acids in total carbon decreased with increasing heating time at high temperature (300 °C), but increased with increasing heating time at ≤ 250 °C. The degree of darkness of the humic acids increased with increasing heating time and temperature. During darkening, the H/C atomic ratios, the proportion of aromatic C, and the carbon and nitrogen stable isotope ratios increased, whereas the proportions of alkyl C and O-alkyl C decreased. X-ray diffraction analysis verified that a stacking nanostructure developed by heating. Changes in the chemical structure of the humic acids from the heated soils depended on the type of soil. The major structural components of the humic acids from the heated Entisol were aromatic C and carboxylic C, whereas aliphatic C, aromatic C, and carboxylic C structural components were found in the humic acids from the heated Inceptisol. These results suggest that the heat-induced changes in the chemical structure of the humic acids depended on the source plant. - Highlights: • Darkness of humic acids increased with increasing heating time and temperature. • Aromatic carbon content increased during darkening. • Carbon and nitrogen stable isotope

Implementing cloud storage with OpenStack Swift

CERN Document Server

Rajana, Kris; Varma, Sreedhar

2014-01-01

This tutorial-based book has a step-by-step approach for each topic, ensuring it is thoroughly covered and easy to follow. If you are an IT administrator who wants to enter the world of cloud storage using OpenStack Swift, then this book is ideal for you. Whether your job is to build, manage, or use OpenStack Swift, this book is an ideal way to move your career ahead. Only basic Linux and server technology skills are expected, to take advantage of this book.

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards for bypass/bleeder stacks. 63.307 Section 63.307 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1) Except as otherwise...

Modeling the kinematics of multi-axial composite laminates as a stacking of 2D TIF plies

Science.gov (United States)

Ibañez, Ruben; Abisset-Chavanne, Emmanuelle; Chinesta, Francisco; Huerta, Antonio

2016-10-01

Thermoplastic composites are widely considered in structural parts. In this paper attention is paid to sheet forming of continuous fiber laminates. In the case of unidirectional prepregs, the ply constitutive equation is modeled as a transversally isotropic fluid, that must satisfy both the fiber inextensibility as well as the fluid incompressibility. When the stacking sequence involves plies with different orientations the kinematics of each ply during the laminate deformation varies significantly through the composite thickness. In our former works we considered two different approaches when simulating the squeeze flow induced by the laminate compression, the first based on a penalty formulation and the second one based on the use of Lagrange multipliers. In the present work we propose an alternative approach that consists in modeling each ply involved in the laminate as a transversally isotropic fluid - TIF - that becomes 2D as soon as incompressibility constraint and plane stress assumption are taken into account. Thus, composites laminates can be analyzed as a stacking of 2D TIF models that could eventually interact by using adequate friction laws at the inter-ply interfaces.

Continued SOFC cell and stack technology and improved production methods

Energy Technology Data Exchange (ETDEWEB)

Wandel, M.; Brodersen, K.; Phair, J. (and others)

2009-05-15

Within this project significant results are obtained on a number of very diverse areas ranging from development of cell production, metallic creep in interconnect to assembling and test of stacks with foot print larger than 500 cm2. Out of 38 milestones 28 have been fulfilled and 10 have been partly fulfilled. This project has focused on three main areas: 1) The continued cell development and optimization of manufacturing processes aiming at production of large foot-print cells, improving cell performance and development environmentally more benign production methods. 2) Stack technology - especially stacks with large foot print and improving the stack design with respect to flow geometry and gas leakages. 3) Development of stack components with emphasis on sealing (for 2G as well as 3G), interconnect (coat, architecture and creep) and test development. Production of cells with a foot print larger than 500 cm2 is very difficult due to the brittleness of the cells and great effort has been put into this topic. Eight cells were successfully produced making it possible to assemble and test a real stack thereby giving valuable results on the prospects of stacks with large foot print. However, the yield rate is very low and a significant development to increase this yield lies ahead. Several lessons were learned on the stack level regarding 'large foot print' stacks. Modelling studies showed that the width of the cell primarily is limited by production and handling of the cell whereas the length (in the flow direction) is limited by e.g. pressure drop and necessary manifolding. The optimal cell size in the flow direction was calculated to be between approx20 cm and < 30 cm. From an economical point of view the production yield is crucial and stacks with large foot print cell area are only feasible if the cell production yield is significantly enhanced. Co-casting has been pursued as a production technique due to the possibilities in large scale production

Production and Reliability Oriented SOFC Cell and Stack Design

DEFF Research Database (Denmark)

Hauth, Martin; Lawlor, Vincent; Cartellieri, Peter

2017-01-01

The paper presents an innovative development methodology for a production and reliability oriented SOFC cell and stack design aiming at improving the stacks robustness, manufacturability, efficiency and cost. Multi-physics models allowed a probabilistic approach to consider statistical variations...... in production, material and operating parameters for the optimization phase. A methodology for 3D description of spatial distribution of material properties based on a random field models was developed and validated by experiments. Homogenized material models on multiple levels of the SOFC stack were...... and output parameters and to perform a sensitivity analysis were developed and implemented. The capabilities of the methodology is illustrated on two practical cases....

Theory and experiment on electromagnetic-wave-propagation velocities in stacked superconducting tunnel structures

DEFF Research Database (Denmark)

Sakai, S.; Ustinov, A. V.; Kohlstedt, H.

1994-01-01

Characteristic velocities of the electromagnetic waves propagating in vertically stacked Josephson transmission are theoretically discussed. An equation for solving n velocities of the waves in an n Josephson-junction stack is derived. The solutions of two- and threefold stacks are especially...... focused on. Furthermore, under the assumption that all parameters of the layers are equal, analytic solutions for a generic N-fold stack are presented. The velocities of the waves in two- and three-junction stacks by Nb-Al-AlOx-Nb systems are experimentally obtained by measuring the cavity resonance...

Testing the sampling efficiency of a nuclear power station stack monitor

Energy Technology Data Exchange (ETDEWEB)

Stroem, L.H. [Instrumentinvest, Nykoeping (Sweden)

1997-08-01

The test method comprises the injection of known amounts of monodisperse particles in the stack air stream, at a suitable point upstream of the sampling installation. To find a suitable injection polls, the gas flow was mapped by means of a tracer gas, released in various points in the stack base. The resulting concentration distributions at the stack sampler level were observed by means of an array of gas detectors. An injection point that produced symmetrical distribution over the stack area, and low concentrations at the stack walls was selected for the particle tests. Monodisperse particles of 6, 10, and 19 {mu}m aerodynamic diameter, tagged with dysprosium, were dispersed in the selected injection point. Particle concentration at the sampler level was measured. The losses to the stack walls were found to be less than 10 %. The particle concentrations at the four sampler inlets were calculated from the observed gas distribution. The amount calculated to be aspirated into the sampler piping was compared with the quantity collected by the sampling train ordinary filter, to obtain the sampling line transmission efficiency. 1 ref., 2 figs.

ejIP: A TCP/IP Stack for Embedded Java

DEFF Research Database (Denmark)

Schoeberl, Martin

2011-01-01

present the design and implementation of a network stack written entirely in Java. This implementation serves as an example how to implement system functions in a safe language and gives evidence that Java can be used for operating system related functionality. The described TCP/IP stack ejIP has already...

Review of measurement techniques for stack monitoring of long-lived alpha emitters

International Nuclear Information System (INIS)

Kordas, J.F.; Phelps, P.L.

1978-01-01

As a result of the promulgation of new guidelines by the Environmental Protection Agency (40 CFR 190) for releases of long-lived, alpha-emitting substances, the stack-monitoring requirements for measuring long-lived alpha particles may change in terms of both monitored isotopes and the detection levels. This paper briefly reviews stack-monitoring requirements for long-lived alpha-emitting particles. It also examines the currently deployed alpha-particulate, stack-monitoring systems and discusses prototype systems that may be applicable to stack monitoring

GeTe sequences in superlattice phase change memories and their electrical characteristics

Energy Technology Data Exchange (ETDEWEB)

Ohyanagi, T., E-mail: ohyanagi@leap.or.jp; Kitamura, M.; Takaura, N. [Low-Power Electronics Association and Projects (LEAP), Onogawa 16-1, Tsukuba, Ibaraki 305-8569 (Japan); Araidai, M. [Department of Computational Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Kato, S. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Shiraishi, K. [Department of Computational Science and Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan)

2014-06-23

We studied GeTe structures in superlattice phase change memories (superlattice PCMs) with a [GeTe/Sb{sub 2}Te{sub 3}] stacked structure by X-ray diffraction (XRD) analysis. We examined the electrical characteristics of superlattice PCMs with films deposited at different temperatures. It was found that XRD spectra differed between the films deposited at 200 °C and 240 °C; the differences corresponded to the differences in the GeTe sequences in the films. We applied first-principles calculations to calculate the total energy of three different GeTe sequences. The results showed the Ge-Te-Ge-Te sequence had the lowest total energy of the three and it was found that with this sequence the superlattice PCMs did not run.

LOFT diesel generator ''A'' exhaust stack seismic analysis

International Nuclear Information System (INIS)

Blandford, R.K.

1978-01-01

A stress analysis of the LOFT Diesel Generator ''A'' Exhaust Stack was performed to determine its reaction to Safe-Shutdown Earthquake loads. The exhaust stack silencer and supporting foundation was found to be inadequate for the postulated seismic accelerations. Lateral support is required to prevent overturning of the silencer pedestal and reinforcement of the 4'' x 0.5'' silencer base straps is necessary. Basic requirements for this additional support are discussed

Numerical and experimental studies of stack shunt current for vanadium redox flow battery

International Nuclear Information System (INIS)

Yin, Cong; Guo, Shaoyun; Fang, Honglin; Liu, Jiayi; Li, Yang; Tang, Hao

2015-01-01

Highlights: • A coupled three-dimensional model of VRB cell stack is developed. • Shunt current of the stack is studied with the model and experiment. • Increased electrolyte resistance in channel and manifold lowers the shunt current. • Shunt current loss increases with stack cell number nonlinearly. - Abstract: The stack shunt current of VRB (vanadium redox flow battery) was investigated with experiments and 3D (three-dimensional) simulations. In the proposed model, cell voltages and electrolyte conductivities were calculated based on electrochemical reaction distributions and SOC (state of charge) values, respectively, while coulombic loss was estimated according to shunt current and vanadium ionic crossover through membrane. Shunt current distributions and coulombic efficiency are analyzed in terms of electrolyte conductivities and stack cell numbers. The distributions of cell voltages and shunt currents calculated with proposed model are validated with single cell and short stack tests. The model can be used to optimize VRB stack manifold and channel designs to improve VRB system efficiency

Some important results from the air pollution distribution model STACKS (1988-1992)

International Nuclear Information System (INIS)

Erbrink, J.J.

1993-01-01

Attention is paid to the results of the study on the distribution of air pollutants by high chimney-stacks of electric power plants. An important product of the study is the integrated distribution model STACKS (Short Term Air-pollutant Concentrations Kema modelling System). The improvements and the extensions of STACKS are described in relation to the National Model, which has been used to estimate the environmental effects of individual chimney-stacks. The National Model shows unacceptable variations for high pollutant sources. Based on the results of STACKS revision of the National model has been taken into consideration. By means of the revised National Model a more realistic estimation of the environmental effects of electric power plants can be carried out

Improved solid oxide fuel cell stacks: Power density, durability and modularity. Final report

Energy Technology Data Exchange (ETDEWEB)

Lund Frandsen, H.; Kiebach, W.R.; Hoeegh, J. (Technical Univ. of Denmark. Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)) (and others)

2010-10-15

This report presents the work performed within the project PSO2009-1-10207 during the period from 01-04-2009 - 31-06-2010. The report is divided into three parts covering the three work packages: Stack components; Stacks and durability; and Large SOFC systems: modularity and scalability. The project contains 38 milestones and all milestones in the project have been either fully or partly fulfilled. Two major achievements within this project concern the robustness towards dynamic operations and implementation of cells with more active cathodes: Within this project tools to evaluate and test SOFC stacks with respect to robustness during dynamic operations has been developed. From stack tests performed under dynamic conditions it was observed that the effect on degradation and failure seemed to be very little. The thermo-mechanical models developed in this project in combination with the dynamic stack model was used in combination to understand why. The results clearly showed that the hardest stress field applied to the cells arises from the steady state operating point rather than from the dynamic conditions. This is a very promising result concerning the fact that especially small CHP units in a commercial system will experience dynamic conditions from load cycling and thermal cycling. A new type of cell with a more active cathode has been formulated and introduced into the TOFC stacks in this project. The aim was to improve the effect of the stack by 25 %. However, compared to a standard stack with the ''old'' cells, the stack effect was increased by 44% - from a cross flow stack with standard 2G cells to a cross flow stack with 2.5G cells. The new type of cells also show an excellent stability towards moisture in the cathode feed, and a stack with 2.5G cells has been tested for 12.000 hrs with a degradation rate of 30 mOMEGAcm2/1000 hr. (Author)

Stacking dependence of carrier transport properties in multilayered black phosphorous

Science.gov (United States)

Sengupta, A.; Audiffred, M.; Heine, T.; Niehaus, T. A.

2016-02-01

We present the effect of different stacking orders on carrier transport properties of multi-layer black phosphorous. We consider three different stacking orders AAA, ABA and ACA, with increasing number of layers (from 2 to 6 layers). We employ a hierarchical approach in density functional theory (DFT), with structural simulations performed with generalized gradient approximation (GGA) and the bandstructure, carrier effective masses and optical properties evaluated with the meta-generalized gradient approximation (MGGA). The carrier transmission in the various black phosphorous sheets was carried out with the non-equilibrium green’s function (NEGF) approach. The results show that ACA stacking has the highest electron and hole transmission probabilities. The results show tunability for a wide range of band-gaps, carrier effective masses and transmission with a great promise for lattice engineering (stacking order and layers) in black phosphorous.

Extended Life PZT Stack Test Fixture

Science.gov (United States)

Badescu, Mircea; Sherrit, S.; Bao, X.; Aldrich, J.; Bar-Cohen, Y.; Jones, C.

2009-01-01

Piezoelectric stacks are being sought to be used as actuators for precision positioning and deployment of mechanisms in future planetary missions. Beside the requirement for very high operation reliability, these actuators are required for operation at space environments that are considered harsh compared to normal terrestrial conditions.These environmental conditions include low and high temperatures and vacuum or high pressure. Additionally, the stacks are subjected to high stress and in some applications need to operate with a very long lifetime durability.Many of these requirements are beyond the current industry design margins for nominal terrestrial applications. In order to investigate some of the properties that will indicate the durability of such actuators and their limitations we have developed a new type of test fixture that can be easily integrated in various test chambers for simulating environmental conditions, can provide access for multiple measurements while being exposed to adjustable stress levels. We designed and built two test fixtures and these fixtures were made to be adjustable for testing stacks with different dimensions and can be easily used in small or large numbers. The properties that were measured using these fixtures include impedance, capacitance, dielectric loss factor, leakage current, displacement, breakdown voltage, and lifetime performance. The fixtures characteristics and the test capabilities are presented in this paper.

Safety Evaluation of Radioactive Material Transport Package under Stacking Test Condition

International Nuclear Information System (INIS)

Lee, Ju Chan; Seo, Ki Seog; Yoo, Seong Yeon

2012-01-01

Radioactive waste transport package was developed to transport eight drums of low and intermediate level waste(LILW) in accordance with the IAEA and domestic related regulations. The package is classified with industrial package IP-2. IP-2 package is required to undergo a free drop test and a stacking test. After free drop and stacking tests, it should prevent the loss or dispersal of radioactive contents, and loss of shielding integrity which would result in more than 20 % increase in the radiation level at any external surface of the package. The objective of this study is to establish the safety test method and procedure for stacking test and to prove the structural integrities of the IP-2 package. Stacking test and analysis were performed with a compressive load equal to five times the weight of the package for a period of 24 hours using a full scale model. Strains and displacements were measured at the corner fitting of the package during the stacking test. The measured strains and displacements were compared with the analysis results, and there were good agreements. It is very difficult to measure the deflection at the container base, so the maximum deflection of the container base was calculated by the analysis method. The maximum displacement at the corner fitting and deflection at the container base were less than their allowable values. Dimensions of the test model, thickness of shielding material and bolt torque were measured before and after the stacking test. Throughout the stacking test, it was found that there were no loss or dispersal of radioactive contents and no loss of shielding integrity. Thus, the package was shown to comply with the requirements to maintain structural integrity under the stacking condition.

Loop Entropy Assists Tertiary Order: Loopy Stabilization of Stacking Motifs

Directory of Open Access Journals (Sweden)

Daniel P. Aalberts

2011-11-01

Full Text Available The free energy of an RNA fold is a combination of favorable base pairing and stacking interactions competing with entropic costs of forming loops. Here we show how loop entropy, surprisingly, can promote tertiary order. A general formula for the free energy of forming multibranch and other RNA loops is derived with a polymer-physics based theory. We also derive a formula for the free energy of coaxial stacking in the context of a loop. Simulations support the analytic formulas. The effects of stacking of unpaired bases are also studied with simulations.

Calculation of AC losses in large HTS stacks and coils

DEFF Research Database (Denmark)

Zermeno, Victor; Abrahamsen, Asger Bech; Mijatovic, Nenad

2012-01-01

In this work, we present a homogenization method to model a stack of HTS tapes under AC applied transport current or magnetic field. The idea is to find an anisotropic bulk equivalent for the stack of tapes, where the internal alternating structures of insulating, metallic, superconducting...... allowing for overcritical current densities to be considered. The method presented here allowed for a computational speedup factor of up to 2 orders of magnitude when compared to full 2-D simulations taking into account the actual structure of the stacks without compromising accuracy....

Multipole Stack for the 800 MeV PS Booster

CERN Multimedia

1975-01-01

The 800 MeV PS Booster had seen first beam in its 4 superposed rings in 1972, routine operation began in 1973. In the strive for ever higher beam intensities, the need for additional multipole lenses became evident. After detailed studies, the manufacture of 8 stacks of multipoles was launched in 1974. Each stack consists of 4 superposed multipoles and each multipole has 4 concentric shells. From the innermost to the outermost shell, Type A contains octupole, skew-octupole, sextupole, skew-sextupole. Type B contains skew-octupole, skew-sextupole, vertical dipole, horizontal dipole. Completion of installation in 1976 opened the way to higher beam intensities. M. Battiaz is seen here with a multipole stack and its many electrical connections.

Multi-Stacked Supported Lipid Bilayer Micropatterning through Polymer Stencil Lift-Off

Directory of Open Access Journals (Sweden)

Yujie Zhu

2015-08-01

Full Text Available Complex multi-lamellar structures play a critical role in biological systems, where they are present as lamellar bodies, and as part of biological assemblies that control energy transduction processes. Multi-lamellar lipid layers not only provide interesting systems for fundamental research on membrane structure and bilayer-associated polypeptides, but can also serve as components in bioinspired materials or devices. Although the ability to pattern stacked lipid bilayers at the micron scale is of importance for these purposes, limited work has been done in developing such patterning techniques. Here, we present a simple and direct approach to pattern stacked supported lipid bilayers (SLBs using polymer stencil lift-off and the electrostatic interactions between cationic and anionic lipids. Both homogeneous and phase-segregated stacked SLB patterns were produced, demonstrating that the stacked lipid bilayers retain lateral diffusivity. We demonstrate patterned SLB stacks of up to four bilayers, where fluorescence resonance energy transfer (FRET and quenching was used to probe the interactions between lipid bilayers. Furthermore, the study of lipid phase behaviour showed that gel phase domains align between adjacent layers. The proposed stacked SLB pattern platform provides a robust model for studying lipid behaviour with a controlled number of bilayers, and an attractive means towards building functional bioinspired materials or devices.

Low-Energy Electron-Induced Strand Breaks in Telomere-Derived DNA Sequences-Influence of DNA Sequence and Topology.

Science.gov (United States)

Rackwitz, Jenny; Bald, Ilko

2018-03-26

During cancer radiation therapy high-energy radiation is used to reduce tumour tissue. The irradiation produces a shower of secondary low-energy (DNA very efficiently by dissociative electron attachment. Recently, it was suggested that low-energy electron-induced DNA strand breaks strongly depend on the specific DNA sequence with a high sensitivity of G-rich sequences. Here, we use DNA origami platforms to expose G-rich telomere sequences to low-energy (8.8 eV) electrons to determine absolute cross sections for strand breakage and to study the influence of sequence modifications and topology of telomeric DNA on the strand breakage. We find that the telomeric DNA 5'-(TTA GGG) 2 is more sensitive to low-energy electrons than an intermixed sequence 5'-(TGT GTG A) 2 confirming the unique electronic properties resulting from G-stacking. With increasing length of the oligonucleotide (i.e., going from 5'-(GGG ATT) 2 to 5'-(GGG ATT) 4 ), both the variety of topology and the electron-induced strand break cross sections increase. Addition of K + ions decreases the strand break cross section for all sequences that are able to fold G-quadruplexes or G-intermediates, whereas the strand break cross section for the intermixed sequence remains unchanged. These results indicate that telomeric DNA is rather sensitive towards low-energy electron-induced strand breakage suggesting significant telomere shortening that can also occur during cancer radiation therapy. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Test of Hydrogen-Oxygen PEM Fuel Cell Stack at NASA Glenn Research Center

Science.gov (United States)

Bents, David J.; Scullin, Vincent J.; Chang, Bei-Jiann; Johnson, Donald W.; Garcia, Christopher P.; Jakupca, Ian J.

2003-01-01

This paper describes performance characterization tests of a 64 cell hydrogen oxygen PEM fuel cell stack at NASA Glenn Research Center in February 2003. The tests were part of NASA's ongoing effort to develop a regenerative fuel cell for aerospace energy storage applications. The purpose of the tests was to verify capability of this stack to operate within a regenerative fuel cell, and to compare performance with earlier test results recorded by the stack developer. Test results obtained include polarization performance of the stack at 50 and 100 psig system pressure, and a steady state endurance run at 100 psig. A maximum power output of 4.8 kWe was observed during polarization runs, and the stack sustained a steady power output of 4.0 kWe during the endurance run. The performance data obtained from these tests compare reasonably close to the stack developer's results although some additional spread between best to worst performing cell voltages was observed. Throughout the tests, the stack demonstrated the consistent performance and repeatable behavior required for regenerative fuel cell operation.

Analyses of Large Coal-Based SOFCs for High Power Stack Block Development

Energy Technology Data Exchange (ETDEWEB)

Recknagle, Kurtis P; Koeppel, Brian J

2010-10-01

This report summarizes the numerical modeling and analytical efforts for SOFC stack development performed for the coal-based SOFC program. The stack modeling activities began in 2004, but this report focuses on the most relevant results obtained since August 2008. This includes the latter half of Phase-I and all of Phase-II activities under technical guidance of VPS and FCE. The models developed to predict the thermal-flow-electrochemical behaviors and thermal-mechanical responses of generic planar stacks and towers are described. The effects of cell geometry, fuel gas composition, on-cell reforming, operating conditions, cell performance, seal leak, voltage degradation, boundary conditions, and stack height are studied. The modeling activities to evaluate and achieve technical targets for large stack blocks are described, and results from the latest thermal-fluid-electrochemical and structural models are summarized. Modeling results for stack modifications such as scale-up and component thickness reduction to realize cost reduction are presented. Supporting modeling activities in the areas of cell fabrication and loss of contact are also described.

Rozšíření modulů OpenStack pro platformu Ansible

OpenAIRE

Šamalík, Adam

2016-01-01

OpenStack je cloudová platforma s distribuovanou architekturou, jejíž instalace je velice komplexní. V této práci navrhnu Ansible Playbook (automatický instalační skript), který OpenStack nainstaluje. OpenStack is a cloud platform with distributed architecture that is very complex to deploy. In this thesis, I will design an Ansible playbok (automatic deployment script) to deploy a custom OpenStack architecture. C

The stack on software and sovereignty

CERN Document Server

Bratton, Benjamin H

2016-01-01

A comprehensive political and design theory of planetary-scale computation proposing that The Stack -- an accidental megastructure -- is both a technological apparatus and a model for a new geopolitical architecture.

Field-induced stacking transition of biofunctionalized trilayer graphene

Energy Technology Data Exchange (ETDEWEB)

Masato Nakano, C. [Flintridge Preparatory School, La Canada, California 91011 (United States); Sajib, Md Symon Jahan; Samieegohar, Mohammadreza; Wei, Tao [Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710 (United States)

2016-02-01

Trilayer graphene (TLG) is attracting a lot of attention as their stacking structures (i.e., rhombohedral vs. Bernal) drastically affect electronic and optical properties. Based on full-atom molecular dynamics simulations, we here predict electric field-induced rhombohedral-to-Bernal transition of TLG tethered with proteins. Furthermore, our simulations show that protein's electrophoretic mobility and diffusivity are enhanced on TLG surface. This phenomenon of controllable TLG stacking transition will contribute to various applications including biosensing.

National Spherical Torus Experiment (NSTX) Center Stack Upgrade

International Nuclear Information System (INIS)

Neumeyer, C.; Avasarala, S.; Chrzanowski, J.; Dudek, L.; Fan, H.; Hatcher, H.; Heitzenroeder, P.; Menard, J.; Ono, M.; Ramakrishnan, S.; Titus, P.; Woolley, R.; Zhan, H.

2009-01-01

The purpose of the NSTX Center Stack Upgrade project is to expand the NSTX operational space and thereby the physics basis for next-step ST facilities. The plasma aspect ratio (ratio of plasma major to minor radius) of the upgrade is increased to 1.5 from the original value of 1.26, which increases the cross sectional area of the center stack by a factor of ∼ 3 and makes possible higher levels of performance and pulse duration.

Thermoacoustic design using stem of goose down stack

Science.gov (United States)

Farikhah, Irna; Ristanto, Sigit; Idrus, Hadiyati; Kaltsum, Ummi; Faisal, Affandi; Setiawan, Ihsan; Setio Utomo, Agung Bambang

2012-09-01

Many refrigerators using CFC as a refrigerant are seen as the cause of the depletion of ozone. Hence, thermoacoustic was chosen as an alternative refrigerator that safe for environment. There are many variable that influenced the optimization of thermoacoustic design. One of them is thermal conductivity of material of stack. The Stack material must have a low thermal conductivity. In this research we used organic stack made of stem of goose down. It has superior thermal insulating. It means that they have the lowest thermal conductivity. The system uses no refrigerant or compressor, and the only mechanical moving part is the loudspeaker connected to a signal generator that produces the acoustic. The working fluid is air and the material of resonator is stainless steel. A series test on the laboratory found that there is a decrease of 5°C in temperature for about 2 minutes.

Absorption spectra of AA-stacked graphite

International Nuclear Information System (INIS)

Chiu, C W; Lee, S H; Chen, S C; Lin, M F; Shyu, F L

2010-01-01

AA-stacked graphite shows strong anisotropy in geometric structures and velocity matrix elements. However, the absorption spectra are isotropic for the polarization vector on the graphene plane. The spectra exhibit one prominent plateau at middle energy and one shoulder structure at lower energy. These structures directly reflect the unique geometric and band structures and provide sufficient information for experimental fitting of the intralayer and interlayer atomic interactions. On the other hand, monolayer graphene shows a sharp absorption peak but no shoulder structure; AA-stacked bilayer graphene has two absorption peaks at middle energy and abruptly vanishes at lower energy. Furthermore, the isotropic features are expected to exist in other graphene-related systems. The calculated results and the predicted atomic interactions could be verified by optical measurements.

Development of a Three Dimensional Neural Sensing Device by a Stacking Method

Directory of Open Access Journals (Sweden)

Chih-Wei Chang

2010-04-01

Full Text Available This study reports a new stacking method for assembling a 3-D microprobe array. To date, 3-D array structures have usually been assembled with vertical spacers, snap fasteners and a supporting platform. Such methods have achieved 3-D structures but suffer from complex assembly steps, vertical interconnection for 3-D signal transmission, low structure strength and large implantable opening. By applying the proposed stacking method, the previous techniques could be replaced by 2-D wire bonding. In this way, supporting platforms with slots and vertical spacers were no longer needed. Furthermore, ASIC chips can be substituted for the spacers in the stacked arrays to achieve system integration, design flexibility and volume usage efficiency. To avoid overflow of the adhesive fluid during assembly, an anti-overflow design which made use of capillary action force was applied in the stacking method as well. Moreover, presented stacking procedure consumes only 35 minutes in average for a 4 × 4 3-D microprobe array without requiring other specially made assembly tools. To summarize, the advantages of the proposed stacking method for 3-D array assembly include simplified assembly process, high structure strength, smaller opening area and integration ability with active circuits. This stacking assembly technique allows an alternative method to create 3-D structures from planar components.

Three dimensional analysis of planar solid oxide fuel cell stack considering radiation

Energy Technology Data Exchange (ETDEWEB)

Tanaka, T.; Inui, Y.; Urata, A.; Kanno, T. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan)

2007-05-15

The authors have been engaged in numerical simulations of the planar type solid oxide fuel cell (SOFC) to make clear the dependence of the cell performance on its operating conditions. Up to now, the authors have already developed the simulation codes for the one channel region and the single cell plate in its cell stack. To calculate accurately the effect of radiation heat transfer from the cell stack surfaces, however, a code that can treat the whole cell stack is necessary. In the present study, therefore, the authors newly develop a three dimensional simulation code of the planar SOFC stack, and the detailed effect of the radiation heat transfer is investigated. It is made clear that the conventional codes are sufficiently accurate, and the newly developed whole cell stack code is not inevitable to predict the maximum cell temperature. This is because the thermal conductivity of the cell materials made of ceramics is very small, and the central part of the cell stack is almost free from the influence of radiation heat transfer. On the other hand, the stack simulation is needed to calculate accurately the cell voltage because the radiation heat transfer reduces it when the ambient temperature is low. The bad influence of low ambient temperature on the voltage is, however, small and relatively high voltage is obtained even when the ambient temperature is very low. (author)

Frequency domain method for the stack of seismic and radar data

Energy Technology Data Exchange (ETDEWEB)

Zhou, H; Sato, M [Tohoku University, Sendai (Japan); Xu, S

1997-10-22

With relation to the stacking method of elastic wave and radar wave, the frequency domain stacking method using the Fourier conversion was proposed as a method for automatically removing errors in time correction leaving advantages of the conventional horizontal stacking method. Concerning an example of wave motion with the same wave form and time difference, as a result of the analysis conducted by this method, it was found that not only effects are kept of suppressing random noise and regular noise in the conventional horizontal stacking method, but the resolution in the original wave motion data is kept. In the example, amplitude of the noise was a half of the wave motion signal, but if it is more than 0.85 times of the wave motion signal, favorable result cannot be obtained in this method. In the analysis in the area where time correction is very difficult and the correction cannot be made completely, it is useful also for the time domain stacking method to acquire data on high resolution of elastic wave and radar wave. 4 refs., 2 figs.

Stack semantics of type theory

DEFF Research Database (Denmark)

Coquand, Thierry; Mannaa, Bassel; Ruch, Fabian

2017-01-01

We give a model of dependent type theory with one univalent universe and propositional truncation interpreting a type as a stack, generalizing the groupoid model of type theory. As an application, we show that countable choice cannot be proved in dependent type theory with one univalent universe...

Dual stacked partial least squares for analysis of near-infrared spectra

Energy Technology Data Exchange (ETDEWEB)

Bi, Yiming [Institute of Automation, Chinese Academy of Sciences, 100190 Beijing (China); Xie, Qiong, E-mail: yimbi@163.com [Institute of Automation, Chinese Academy of Sciences, 100190 Beijing (China); Peng, Silong; Tang, Liang; Hu, Yong; Tan, Jie [Institute of Automation, Chinese Academy of Sciences, 100190 Beijing (China); Zhao, Yuhui [School of Economics and Business, Northeastern University at Qinhuangdao, 066000 Qinhuangdao City (China); Li, Changwen [Food Research Institute of Tianjin Tasly Group, 300410 Tianjin (China)

2013-08-20

Graphical abstract: -- Highlights: •Dual stacking steps are used for multivariate calibration of near-infrared spectra. •A selective weighting strategy is introduced that only a subset of all available sub-models is used for model fusion. •Using two public near-infrared datasets, the proposed method achieved competitive results. •The method can be widely applied in many fields, such as Mid-infrared spectra data and Raman spectra data. -- Abstract: A new ensemble learning algorithm is presented for quantitative analysis of near-infrared spectra. The algorithm contains two steps of stacked regression and Partial Least Squares (PLS), termed Dual Stacked Partial Least Squares (DSPLS) algorithm. First, several sub-models were generated from the whole calibration set. The inner-stack step was implemented on sub-intervals of the spectrum. Then the outer-stack step was used to combine these sub-models. Several combination rules of the outer-stack step were analyzed for the proposed DSPLS algorithm. In addition, a novel selective weighting rule was also involved to select a subset of all available sub-models. Experiments on two public near-infrared datasets demonstrate that the proposed DSPLS with selective weighting rule provided superior prediction performance and outperformed the conventional PLS algorithm. Compared with the single model, the new ensemble model can provide more robust prediction result and can be considered an alternative choice for quantitative analytical applications.

Dual stacked partial least squares for analysis of near-infrared spectra

International Nuclear Information System (INIS)

Bi, Yiming; Xie, Qiong; Peng, Silong; Tang, Liang; Hu, Yong; Tan, Jie; Zhao, Yuhui; Li, Changwen

2013-01-01

Graphical abstract: -- Highlights: •Dual stacking steps are used for multivariate calibration of near-infrared spectra. •A selective weighting strategy is introduced that only a subset of all available sub-models is used for model fusion. •Using two public near-infrared datasets, the proposed method achieved competitive results. •The method can be widely applied in many fields, such as Mid-infrared spectra data and Raman spectra data. -- Abstract: A new ensemble learning algorithm is presented for quantitative analysis of near-infrared spectra. The algorithm contains two steps of stacked regression and Partial Least Squares (PLS), termed Dual Stacked Partial Least Squares (DSPLS) algorithm. First, several sub-models were generated from the whole calibration set. The inner-stack step was implemented on sub-intervals of the spectrum. Then the outer-stack step was used to combine these sub-models. Several combination rules of the outer-stack step were analyzed for the proposed DSPLS algorithm. In addition, a novel selective weighting rule was also involved to select a subset of all available sub-models. Experiments on two public near-infrared datasets demonstrate that the proposed DSPLS with selective weighting rule provided superior prediction performance and outperformed the conventional PLS algorithm. Compared with the single model, the new ensemble model can provide more robust prediction result and can be considered an alternative choice for quantitative analytical applications

User Driven Image Stacking for ODI Data and Beyond via a Highly Customizable Web Interface

Science.gov (United States)

Hayashi, S.; Gopu, A.; Young, M. D.; Kotulla, R.

2015-09-01

While some astronomical archives have begun serving standard calibrated data products, the process of producing stacked images remains a challenge left to the end-user. The benefits of astronomical image stacking are well established, and dither patterns are recommended for almost all observing targets. Some archives automatically produce stacks of limited scientific usefulness without any fine-grained user or operator configurability. In this paper, we present PPA Stack, a web based stacking framework within the ODI - Portal, Pipeline, and Archive system. PPA Stack offers a web user interface with built-in heuristics (based on pointing, filter, and other metadata information) to pre-sort images into a set of likely stacks while still allowing the user or operator complete control over the images and parameters for each of the stacks they wish to produce. The user interface, designed using AngularJS, provides multiple views of the input dataset and parameters, all of which are synchronized in real time. A backend consisting of a Python application optimized for ODI data, wrapped around the SWarp software, handles the execution of stacking workflow jobs on Indiana University's Big Red II supercomputer, and the subsequent ingestion of the combined images back into the PPA archive. PPA Stack is designed to enable seamless integration of other stacking applications in the future, so users can select the most appropriate option for their science.

Reexamination of the ISABELLE box car stacking scheme

International Nuclear Information System (INIS)

Chasman, R.

1975-01-01

Box car stacking of ISABELLE after acceleration of the fundamental frequency in the AGS is reviewed with the present ISABELLE parameters and examined with regard to longitudinal impedence requirements. The scheme results in an impedance tolerance of Z/n less than or equal to 30 Ω compared to Z/n less than or equal to 5 Ω obtained for rf stacking. However, to meet the claimed luminosity, the AGS performance demands are increased above those assumed in the ISABELLE proposal

Seismic fragility of ventilation stack of nuclear power plant

International Nuclear Information System (INIS)

Nefedov, S.S.; Yugai, T.Z.; Kalinkin, I.V.; Vizir, P.L.

2003-01-01

Fragility study of safety related elements is necessary step in seismic PSA of nuclear power plant (NPP). In present work fragility was analyzed after the example of the ventilation stack of NPP. Ventilation stack, considered in present work, is a separately erected construction with height of 100 m made of cast-in-place reinforced concrete. In accordance with IAEA terminology fragility of element is defined as conditional probability of its failure at given level of seismic loading. Failure of a ventilation stack was considered as development of the plastic hinge in some section of a shaft. Seismic ground acceleration a, which corresponds to failure, could be defined as limit seismic acceleration of ventilation stack [a]. Limit seismic acceleration [a] was considered as random value. Sources of its variation are connected with stochastic nature of factors determining it (properties of construction materials, soils etc.), and also with uncertainties of existing analytical techniques. Random value [a] was assumed to be distributed lognormally. Median m[a] and logarithmically standard deviation β of this distribution were defined by 'scaling method' developed by R.P. Kennedy et al. Using this values fragility curves were plotted for different levels of confidence probability. (author)

Die-stacking architecture

CERN Document Server

Xie, Yuan

2015-01-01

The emerging three-dimensional (3D) chip architectures, with their intrinsic capability of reducing the wire length, promise attractive solutions to reduce the delay of interconnects in future microprocessors. 3D memory stacking enables much higher memory bandwidth for future chip-multiprocessor design, mitigating the ""memory wall"" problem. In addition, heterogenous integration enabled by 3D technology can also result in innovative designs for future microprocessors. This book first provides a brief introduction to this emerging technology, and then presents a variety of approaches to design

Stacking fault growth of FCC crystal: The Monte-Carlo simulation approach

International Nuclear Information System (INIS)

Jian Jianmin; Ming Naiben

1988-03-01

The Monte-Carlo method has been used to simulate the growth of the FCC (111) crystal surface, on which is presented the outcrop of a stacking fault. The comparison of the growth rates has been made between the stacking fault containing surface and the perfect surface. The successive growth stages have been simulated. It is concluded that the outcrop of stacking fault on the crystal surface can act as a self-perpetuating step generating source. (author). 7 refs, 3 figs

Reliability prediction of large fuel cell stack based on structure stress analysis

Science.gov (United States)

Liu, L. F.; Liu, B.; Wu, C. W.

2017-09-01

The aim of this paper is to improve the reliability of Proton Electrolyte Membrane Fuel Cell (PEMFC) stack by designing the clamping force and the thickness difference between the membrane electrode assembly (MEA) and the gasket. The stack reliability is directly determined by the component reliability, which is affected by the material property and contact stress. The component contact stress is a random variable because it is usually affected by many uncertain factors in the production and clamping process. We have investigated the influences of parameter variation coefficient on the probability distribution of contact stress using the equivalent stiffness model and the first-order second moment method. The optimal contact stress to make the component stay in the highest level reliability is obtained by the stress-strength interference model. To obtain the optimal contact stress between the contact components, the optimal thickness of the component and the stack clamping force are optimally designed. Finally, a detailed description is given how to design the MEA and gasket dimensions to obtain the highest stack reliability. This work can provide a valuable guidance in the design of stack structure for a high reliability of fuel cell stack.

40 CFR 63.7296 - What emission limitations must I meet for battery stacks?

Science.gov (United States)

2010-07-01

... for battery stacks? 63.7296 Section 63.7296 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY..., Quenching, and Battery Stacks Emission Limitations and Work Practice Standards § 63.7296 What emission limitations must I meet for battery stacks? You must not discharge to the atmosphere any emissions from any...

296-B-5 Stack monitoring and sampling system annual system assessment report

International Nuclear Information System (INIS)

Ridge, T.M.

1995-02-01

The B Plant Administration Manual requires an annual system assessment to evaluate and report the present condition of the sampling and monitoring system associated with Stack 296-B-5 at B Plant. The sampling and monitoring system associated with stack 296-B-5 is functional and performing satisfactorily. This document is an annual assessment report of the systems associated with the 296-B-5 stack

Fuel flow distribution in SOFC stacks revealed by impedance spectroscopy

DEFF Research Database (Denmark)

Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, Rasmus

2014-01-01

As SOFC technology is moving closer to a commercial break through, methods to measure the “state-of-health” of operating stacks are becoming of increasing interest. This requires application of advanced methods for detailed electrical and electrochemical characterization during operation. An oper......As SOFC technology is moving closer to a commercial break through, methods to measure the “state-of-health” of operating stacks are becoming of increasing interest. This requires application of advanced methods for detailed electrical and electrochemical characterization during operation...... utilizations. The fuel flow distribution provides important information about the operating limits of the stack when high electrical efficiency is required....

Stacking by electroinjection with discontinuous buffers in capillary zone electrophoresis.

Science.gov (United States)

Shihabi, Zak K

2002-08-01

The work presented here demonstrates that electroinjection can be performed using discontinuous buffers, which can result in better stacking than that obtained by hydrodynamic injection. The sample can be concentrated at the tip of the capillary leaving practically the whole capillary for sample separation. This results in several advantages, such as better sample concentration, higher plate number and shorter time of stacking. However, sample introduction by electromigration is suited for samples free or low in salt content. Samples, which are high in salt content, are better introduced by the hydrodynamic injection for stacking by the discontinuous buffers. Different simple methods to introduce the discontinuity in the buffer for electroinjection are discussed.

Stack Monitoring System At PUSPATI TRIGA Reactor

International Nuclear Information System (INIS)

Zamrul Faizad Omar; Mohd Sabri Minhat; Zareen Khan Abdul Jalil Khan; Ridzuan Abdul Mutalib; Khairulezwan Abdul Manan; Nurfarhana Ayuni Joha; Izhar Abu Hussin

2014-01-01

This paper describes the current Stack Monitoring System at PUSPATI TRIGA Reactor (RTP) building. A stack monitoring system is a continuous air monitor placed at the reactor top for monitoring the presence of radioactive gaseous in the effluent air from the RTP building. The system consists of four detectors that provide the reading for background, particulate, Iodine and Noble gas. There is a plan to replace the current system due to frequent fault of the system, thus thorough understanding of the current system is required. Overview of the whole system will be explained in this paper. Some current results would be displayed and moving forward brief plan would be mentioned. (author)

Frictional forces in an SOFC stack with sliding seals

Energy Technology Data Exchange (ETDEWEB)

Yamazaki, T; Oishi, N; Namikawa, T; Yamazaki, Y [Tokyo Institute of Technology, Tokyo (Japan)

1996-06-05

The detrimental thermal stresses in planar SOFC stacks can be reduced using sliding seals. In the proposal planar stack the electrolyte film is sandwiched by YSZ support rings to release the thermal stresses. In order to estimate the strength of the support ring, the frictional forces between heat resistant alloy and YSZ were measured at 900{degree}C. The coefficient of friction between Hastelloy X and YSZ increased when they were measured lifter 144h heating. However, the coefficient of friction between HA-214 and YSZ did not increase. The measurement and a calculation of the stresses in the support rings led the result that a thickness of 0.6mm was necessary for 200mm diameter support rings under a stack pressure of 0.1kgcm{sup -2}. 6 refs., 9 figs., 1 tab.

Project W420 Air Sampler Probe Placement Qualification Tests for Four 6-Inch Diameter Stacks: 296-A-25, 296-B-28, 296-S-22, and 296-T-18

International Nuclear Information System (INIS)

Maughan, A.D.; Glissmeyer, J.A.

1998-01-01

The W420 project covers the upgrading of effluent monitoring systems at six ventilation exhaust stacks in tank-farm facilities at the U.S. Department of Energy's Hanford Site. The discharge stacks of five of the six systems will be completely replaced. Four of these (296-A-25, 296-B-28, 296-S-22, and 296-T-18) will be of the same size, 6-inches in diameter and about 12-ft high. This report documents tests that were conducted to verify that these four stacks meet the applicable regulatory criteria regarding the placement of the air sampling probe. These criteria ensure that the contaminants in the stack are well mixed with the airflow at the location of the probe such that the extracted sample represents the whole. There are also criteria addressing the transport of the sample to the collection device. These are not covered in this report, but will need to be addressed later. These tests were conducted by Pacific Northwest National Laboratory on a full-scale model of the 6-inch stick. The sequence of tests addresses the acceptability of the flow angle relative to the probe and the uniformity of air velocity and gaseous and particle tracers in the cross section of the stack. All tests were successful, and all acceptance criteria were met

Hexagonal perovskites with cationic vacancies. 5. Structure determination on H-Ba/sub 2/Lusub(2/3)vacantsub(1/3)WO/sub 6/ - a novel rhombohedral stacking polytype with 18 layers

Energy Technology Data Exchange (ETDEWEB)

Wischert, W; Schittenhelm, H J; Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Inst. fuer Chemie

1979-01-01

Compounds of type Ba/sub 2/Bsub(2/3)sup(III)vacantsub(1/3)Wsup(VI)O/sub 6/ with Bsup(III) = Gd-Lu, Y are polymorphic. They crystallize in a cubic 1:1 ordered perovskite structure and in a new rhombohedral perovskite stacking polytype of 18 L respectively. By intensity calculations out of the three possible stacking sequences (4)(2), (5)(1) and (3)1(1)1 (all space group R3m) the sequence (5)(1) can be selected. For H-Ba/sub 2/Lusub(2/3)vacant sub(1/3)WO/sub 6/ the refined R' factor is 14.1%. The structure contains groups of three octahedra connected with another by common faces which are linked with each other by three corner sharing octahedra. In the block of three face sharing octahedra the central octahedral lattice site is vacant, the two outer positions are occupied by tungsten atoms. According to this distribution a direct contact of occupied face sharing octahedra is absent.

A small mono-polar direct methanol fuel cell stack with passive operation

Science.gov (United States)

Chan, Y. H.; Zhao, T. S.; Chen, R.; Xu, C.

A passive direct methanol fuel cell (DMFC) stack that consists of six unit cells was designed, fabricated, and tested. The stack was tested with different methanol concentrations under ambient conditions. It was found that the stack performance increased when the methanol concentration inside the fuel tank was increased from 2.0 to 6.0 M. The improved performance is primarily due to the increased cell temperature as a result of the exothermic reaction between the permeated methanol and oxygen on the cathode. Moreover, the increased cell temperature enhanced the water evaporation rate on the air-breathing cathode, which significantly reduced water flooding on the cathode and further improved the stack performance. This passive DMFC stack, providing 350 mW at 1.8 V, was successfully applied to power a seagull display kit. The seagull display kit can continuously run for about 4 h on a single charge of 25 cm 3 4.0-M methanol solution.

Stacks with TiN/titanium as the bipolar plate for PEMFCs

International Nuclear Information System (INIS)

Ren, Zhijun; Zhang, Dongming; Wang, Zaiyi

2012-01-01

Proton exchange membrane fuel cell (PEMFC) is a potential alternative for the internal combustion engine. But many problems, such as metallic bipolar plate instead of graphite bipolar plate to decrease the cost, should be solved before its application. Based on the previous results that single cell with TiN/Ti as bipolar plates shows high performance and enough long-time durability, the progress on the stacks with TiN/Ti as bipolar plates is reported in this manuscript. Till now seldom report is focused on stacks because of the complicated processing technique, especially for that with TiN/Ti as bipolar plate. The flow field in the plate is punched from titanium deformation, and two plates are welded by laser welding to form one piece of bipolar plate. The adopted processing techniques for stacks with TiN/Ti as bipolar plate exhibit advantage and feasibility in industry. The power density by weight for the stack is as high as 1353 W kg −1 , although it still has space to be improved. Next work should be focused on the design of flow channel parameters and flow field type based on plastic deformation of metal materials. -- Highlights: ► The progress on the stacks with TiN/Ti as bipolar plates is reported. ► The adopted processing techniques exhibit feasibility in industry. ► The power density by weight for the stack is as high as 1353 W kg −1 .

Efficient Context Switching for the Stack Cache: Implementation and Analysis

DEFF Research Database (Denmark)

Abbaspourseyedi, Sahar; Brandner, Florian; Naji, Amine

2015-01-01

, the analysis of the stack cache was limited to individual tasks, ignoring aspects related to multitasking. A major drawback of the original stack cache design is that, due to its simplicity, it cannot hold the data of multiple tasks at the same time. Consequently, the entire cache content needs to be saved...

Optimal Stack Layout in a Sea Container Terminal with Automated Lifting Vehicles

OpenAIRE

Roy, D.; Gupta, A.; Parhi, S.; de Koster, M.B.M.

2014-01-01

textabstractContainer terminal performance is largely determined by its design decisions, which include the number and type of quay cranes (QCs), stack cranes (SCs), transport vehicles, vehicle travel path, and stack layout. The terminal design process is complex because it is affected by factors such as topological constraints, stochastic interactions among the quayside, vehicle transport and stackside operations. Further, the orientation of the stack layout (parallel or perpendicular to the...

Stacked magnet superconducting bearing

International Nuclear Information System (INIS)

Rigney, T.K. II; Saville, M.P.

1993-01-01

A superconducting bearing is described, comprising: a plurality of permanent magnets magnetized end-to-end and stacked side-by-side in alternating polarity, such that flux lines flow between ends of adjacent magnets; isolating means, disposed between said adjacent magnets, for reducing flux leakage between opposing sides of said adjacent magnets; and a member made of superconducting material having at least one surface in communication with said flux lines

Iridium Interfacial Stack (IRIS)

Science.gov (United States)

Spry, David James (Inventor)

2015-01-01

An iridium interfacial stack ("IrIS") and a method for producing the same are provided. The IrIS may include ordered layers of TaSi.sub.2, platinum, iridium, and platinum, and may be placed on top of a titanium layer and a silicon carbide layer. The IrIS may prevent, reduce, or mitigate against diffusion of elements such as oxygen, platinum, and gold through at least some of its layers.

Chernobyl risk reduction via ventilation stack repair: a successful international project

International Nuclear Information System (INIS)

Gore, B.F.; Glukhov, A.Y.; Schmidt, J.P.; Vargo, G.I.; Osterloh, J.V.; Kupny, V.I.; Korneev, A.A.; Matvejev, Y.A.

1999-01-01

The recently completed project to repair the ChNPP Unit 3/4 ventilation stack is the first international project providing a direct physical improvement and safety upgrade at the Shelter (Ukrytie) facility. The 1986 explosion at Chernobyl NPP Unit 4 severely damaged the ventilation stack framework of bracing and its foundation. At one node, where six elements of the framework joined together, one element was completely missing one element was torn from the node and left hanging from its other end, and one element was badly bent and dented. Foundation supports were knocked measurably off plumb. Repair of the ChNPP ventilation stack is the first international project providing direct physical improvement and safety upgrade at the Shelter facility. The repairs have restored the stack to full design strength, from an emergency condition with a high probability of collapse

Device for equalizing molten electrolyte content in a fuel cell stack

Science.gov (United States)

Smith, J.L.

1985-12-23

A device for equalizing the molten electrolyte content throughout the height of a fuel cell stack is disclosed. The device includes a passageway for electrolyte return with electrolyte wettable wicking material in the opposite end portions of the passageway. One end portion is disposed near the upper, negative end of the stack where electrolyte flooding occurs. The second end portion is placed near the lower, positive end of the stack where electrolyte is depleted. Heating means are provided at the upper portion of the passageway to increase electrolyte vapor pressure in the upper wicking material. The vapor is condensed in the lower passageway portion and conducted as molten electrolyte in the lower wick to the positive end face of the stack. An inlet is provided to inject a modifying gas into the passageway and thereby control the rate of electrolyte return.

Dose assessment for potential radionuclide emissions from stacks on the Hanford Site: NESHAP compliance

International Nuclear Information System (INIS)

Davis, W.E.; Barnett, J.M.; Kenoyer, J.L.

1994-03-01

The purpose of this document is to present the assessment results for the registered stacks on the Hanford Site for potential emissions, i.e. emissions with no control devices in place. Further, the document will identify those stacks requiring continuous monitoring, i.e. the effective dose equivalent from potential emissions >0.1 mrem/yr. The stack assessment of potential emissions was performed on 84 registered stacks on the Hanford Site. These emission sources represent individual point sources presently registered under Washington Administrative code 246-247 with the Washington Department of Health. The methods used in assessing the potential emissions from the stacks are described

Computational analysis of sequence selection mechanisms.

Science.gov (United States)

Meyerguz, Leonid; Grasso, Catherine; Kleinberg, Jon; Elber, Ron

2004-04-01

Mechanisms leading to gene variations are responsible for the diversity of species and are important components of the theory of evolution. One constraint on gene evolution is that of protein foldability; the three-dimensional shapes of proteins must be thermodynamically stable. We explore the impact of this constraint and calculate properties of foldable sequences using 3660 structures from the Protein Data Bank. We seek a selection function that receives sequences as input, and outputs survival probability based on sequence fitness to structure. We compute the number of sequences that match a particular protein structure with energy lower than the native sequence, the density of the number of sequences, the entropy, and the "selection" temperature. The mechanism of structure selection for sequences longer than 200 amino acids is approximately universal. For shorter sequences, it is not. We speculate on concrete evolutionary mechanisms that show this behavior.

The operation and monitoring of sewage disposal by stack injection

Energy Technology Data Exchange (ETDEWEB)

Jensen, D.A. [Alyeska Pipeline Service Co. (United States)

1994-12-31

A system that uses turbine exhaust to evaporate sewage, was described. The Alyeska Pipeline Service developed the system for isolated pump stations located in permafrost areas. The pumps moving the crude oil in the Trans Alaska Pipeline System (TAPS) were driven by simple cycle gas turbine engines which produce large amounts of waste heat. The waste heat was used to evaporate the sewage effluent, effectively destroying all pathogens in it. The process, known as `stack injection`, was recently upgraded to increase efficiency and safety. Stack injection was being used at five pump stations. Methods used to control operation of the stack injection system, and field data used to redesign the system were reviewed. 3 figs., 3 refs.

Laser-plasma acceleration with multi-color pulse stacks: Designer electron beams for advanced radiation sources

Science.gov (United States)

Kalmykov, Serge; Shadwick, Bradley; Ghebregziabher, Isaac; Davoine, Xavier

2015-11-01

Photon engineering offers new avenues to coherently control electron beam phase space on a femtosecond time scale. It enables generation of high-quality beams at a kHz-scale repetition rate. Reducing the peak pulse power (and thus the average laser power) is the key to effectively exercise such control. A stepwise negative chirp, synthesized by incoherently stacking collinear sub-Joule pulses from conventional CPA, affords a micron-scale bandwidth. It is sufficient to prevent rapid compression of the pulse into an optical shock, while delaying electron dephasing. This extends electron energy far beyond the limits suggested by accepted scalings (beyond 1 GeV in a 3 mm plasma), without compromising beam quality. In addition, acceleration with a stacked pulse in a channel favorably modifies electron beam on a femtosecond time scale, controllably producing synchronized sequences of 100 kA-scale, quasi-monoenergetic bunches. These comb-like, designer GeV electron beams are ideal drivers of polychromatic, tunable inverse Thomson γ-ray sources. The work of SYK and BAS is supported by the US DOE Grant DE-SC0008382 and NSF Grant PHY-1104683. Inverse Thomson scattering simulations were completed utilizing the Holland Computing Center of the University of Nebraska.

Distinct Element Method modelling of fold-related fractures in a multilayer sequence

Science.gov (United States)

Kaserer, Klemens; Schöpfer, Martin P. J.; Grasemann, Bernhard

2017-04-01

Natural fractures have a significant impact on the performance of hydrocarbon systems/reservoirs. In a multilayer sequence, both the fracture density within the individual layers and the type of fracture intersection with bedding contacts are key parameters controlling fluid pathways. In the present study the influence of layer stacking and interlayer friction on fracture density and connectivity within a folded sequence is systematically investigated using 2D Distinct Element Method modelling. Our numerical approach permits forward modelling of both fracture nucleation/propagation/arrest and (contemporaneous) frictional slip along bedding planes in a robust and mechanically sound manner. Folding of the multilayer sequence is achieved by enforcing constant curvature folding by means of a velocity boundary condition at the model base, while a constant overburden pressure is maintained at the model top. The modelling reveals that with high bedding plane friction the multilayer stack behaves mechanically as a single layer so that the neutral surface develops in centre of the sequence and fracture spacing is controlled by the total thickness of the folded sequence. In contrast, low bedding plane friction leads to decoupling of the individual layers (flexural slip folding) so that a neutral surface develops in the centre of each layer and fracture spacing is controlled by the thickness of the individual layers. The low interfacial friction models illustrate that stepping of fractures across bedding planes is a common process, which can however have two contrasting origins: The mechanical properties of the interface cause fracture stepping during fracture propagation. Originally through-going fractures are later offset by interfacial slip during folding. A combination of these two different origins may lead to (apparently) inconsistent fracture offsets across bedding planes within a flexural slip fold.

Power sources involving ~ 300W PEMFC fuel cell stacks cooled by different media

Directory of Open Access Journals (Sweden)

Dudek Magdalena

2017-01-01

Full Text Available Two constructions of ~300W PEMFC stacks, cooled by different media, were analysed. An open-cathode ~300W PEMFC stack cooled by air (Horizon, Singapore and a PEMFC F-42 stack cooled by a liquid medium (Schunk, Germany were chosen for all of the investigations described in this paper. The potential for the design and construction of power sources involving fuel cells, as well as of a hybrid system (fuel cell-lithium battery for mobile and stationary applications, is presented and discussed. The impact of certain experimental parameters on PEMFC stack performance is analysed and discussed.

Taxonomy of multi-focal nematode image stacks by a CNN based image fusion approach.

Science.gov (United States)

Liu, Min; Wang, Xueping; Zhang, Hongzhong

2018-03-01

In the biomedical field, digital multi-focal images are very important for documentation and communication of specimen data, because the morphological information for a transparent specimen can be captured in form of a stack of high-quality images. Given biomedical image stacks containing multi-focal images, how to efficiently extract effective features from all layers to classify the image stacks is still an open question. We present to use a deep convolutional neural network (CNN) image fusion based multilinear approach for the taxonomy of multi-focal image stacks. A deep CNN based image fusion technique is used to combine relevant information of multi-focal images within a given image stack into a single image, which is more informative and complete than any single image in the given stack. Besides, multi-focal images within a stack are fused along 3 orthogonal directions, and multiple features extracted from the fused images along different directions are combined by canonical correlation analysis (CCA). Because multi-focal image stacks represent the effect of different factors - texture, shape, different instances within the same class and different classes of objects, we embed the deep CNN based image fusion method within a multilinear framework to propose an image fusion based multilinear classifier. The experimental results on nematode multi-focal image stacks demonstrated that the deep CNN image fusion based multilinear classifier can reach a higher classification rate (95.7%) than that by the previous multilinear based approach (88.7%), even we only use the texture feature instead of the combination of texture and shape features as in the previous work. The proposed deep CNN image fusion based multilinear approach shows great potential in building an automated nematode taxonomy system for nematologists. It is effective to classify multi-focal image stacks. Copyright © 2018 Elsevier B.V. All rights reserved.

Retrofitting of an improved stack monitoring system in Rajasthan atomic power station

International Nuclear Information System (INIS)

Natarajan, K.

1985-01-01

The problems encountered in the measurement of inert gas activities, iodine activity and tritium activity released through the stack in RAPS are described and the considerations for the development of improved instruments outlined. The new approach provides for better accuracy of measurement of all the relevant radioactive parameters in the stack at one centralised place. The construction work in the station for the newly conceived stack activity monitoring system is completed and the earlier equipment used is installed in the room temporarily. Development prototypes of stack inert gas monitoring system and iodine monitoring system as described in Section 5 are made and evaluated. Fabrication of new equipment for retrofitting in RAPS is in progress and these will replace the equipment temporarily installed in the station

Continued maturing of SOFC cell production technology and development and demonstration of SOFC stacks. Final report

Energy Technology Data Exchange (ETDEWEB)

2008-08-15

The overall objective of the 6385 project was to develop stack materials, components and stack technology including industrial relevant manufacturing methods for cells components and stacks. Furthermore, the project should include testing and demonstration of the stacks under relevant operating conditions. A production of 6.829 cells, twenty 75-cell stacks and a number of small stacks was achieved. Major improvements were also made in the manufacturing methods and in stack design. Two test and demonstration activities were included in the project. The first test unit was established at H.C. OErsted power plant at the Copenhagen waterfront in order to perform test of SOFC stacks. The unit will be used for tests in other projects. The second demonstration unit is the alpha prototype demonstration in a system running on natural gas in Finland. The alpha prototype demonstration system with 24 TOFC (Topsoe Fuel Cell) stacks was established and started running in October 2007 and operational experience was gained in the period from October 2007 to February 2008. (auther)

Photoswitchable Intramolecular H-Stacking of Perylenebisimide

NARCIS (Netherlands)

Wang, Jiaobing; Kulago, Artem; Browne, Wesley R.; Feringa, Ben L.

2010-01-01

Dynamic control over the formation of H- or J-type aggregates of chromophores is of fundamental importance for developing responsive organic optoelectronic materials. In this study, the first example of photoswitching between a nonstacked and an intramolecularly H-stacked arrangement of

Annex I.G. Demolition of the G1 stack at Marcoule by toppling

International Nuclear Information System (INIS)

2005-01-01

The G1 stack at Marcoule was constructed during the first half of 1956 as a ventilation outlet for the G1 reactor, which is cooled by air. After the G1 reactor was decommissioned, the G1 stack served as a ventilation outlet for two new nuclear facilities on the site. Being no longer in compliance with regulations and having many inadequacies and uncertainties in terms of the prestressed concrete, the stack posed a potential damage risk in extreme wind or in the event of an earthquake. In 1994 it was decided that a new stack would be built to act as an outlet for the existing nuclear facilities, and that the old one would be demolished. The G1 stack was 100 m in height, 10 m in diameter and constructed with 24 vertically stacked concrete rings consisting of nine prefabricated sections, each 3.6 m in height. It was capped by a metal deflector (about 6 m in height and weighing 50 t). The inside consisted of nine semicircular tubes constructed of steel sheet metal weighing 120 t. The base of the stack consisted of the foundation, a plate and a base plate which were constructed at the site. The barrel sections were prefabricated. Construction lasted from January 1956 to June 1956. At the base, the cylindrical portion of the stack widened to form three feet extending to a depth of 7.5 m. The base plate of the stack was formed onsite to the height of 16.7 m and then prestressed using cables. A repair carried out in 1964 included adding a concrete lining of the initial rings of the cylinder up to a level of 22.1 m. Additional prestressing with the base plate and repair of the horizontal and vertical prestressing of the barrel were also carried out, leaving only 22 rings and 43 visible cables. The total mass of the stack was 2170 t, including: - Concrete: cylinder 800 t, base plate 1200 t; - Steel: internal structures 120 t, deflector 50 t. The main radiological risk was the presence of traces of tritium. The radioactive inventory for the entire stack was estimated in 2000

Temperature dependence of stacking faults in catalyst-free GaAs nanopillars.

Science.gov (United States)

Shapiro, Joshua N; Lin, Andrew; Ratsch, Christian; Huffaker, D L

2013-11-29

Impressive opto-electronic devices and transistors have recently been fabricated from GaAs nanopillars grown by catalyst-free selective-area epitaxy, but this growth technique has always resulted in high densities of stacking faults. A stacking fault occurs when atoms on the growing (111) surface occupy the sites of a hexagonal-close-pack (hcp) lattice instead of the normal face-centered-cubic (fcc) lattice sites. When stacking faults occur consecutively, the crystal structure is locally wurtzite instead of zinc-blende, and the resulting band offsets are known to negatively impact device performance. Here we present experimental and theoretical evidence that indicate stacking fault formation is related to the size of the critical nucleus, which is temperature dependent. The difference in energy between the hcp and fcc orientation of small nuclei is computed using density-function theory. The minimum energy difference of 0.22 eV is calculated for a nucleus with 21 atoms, so the population of nuclei in the hcp orientation is expected to decrease as the nucleus grows larger. The experiment shows that stacking fault occurrence is dramatically reduced from 22% to 3% by raising the growth temperature from 730 to 790 ° C. These data are interpreted using classical nucleation theory which dictates a larger critical nucleus at higher growth temperature.

OpenStack cloud computing cookbook

CERN Document Server

Jackson, Kevin

2013-01-01

A Cookbook full of practical and applicable recipes that will enable you to use the full capabilities of OpenStack like never before.This book is aimed at system administrators and technical architects moving from a virtualized environment to cloud environments with familiarity of cloud computing platforms. Knowledge of virtualization and managing linux environments is expected.

Moving object detection in top-view aerial videos improved by image stacking

Science.gov (United States)

Teutsch, Michael; Krüger, Wolfgang; Beyerer, Jürgen

2017-08-01

Image stacking is a well-known method that is used to improve the quality of images in video data. A set of consecutive images is aligned by applying image registration and warping. In the resulting image stack, each pixel has redundant information about its intensity value. This redundant information can be used to suppress image noise, resharpen blurry images, or even enhance the spatial image resolution as done in super-resolution. Small moving objects in the videos usually get blurred or distorted by image stacking and thus need to be handled explicitly. We use image stacking in an innovative way: image registration is applied to small moving objects only, and image warping blurs the stationary background that surrounds the moving objects. Our video data are coming from a small fixed-wing unmanned aerial vehicle (UAV) that acquires top-view gray-value images of urban scenes. Moving objects are mainly cars but also other vehicles such as motorcycles. The resulting images, after applying our proposed image stacking approach, are used to improve baseline algorithms for vehicle detection and segmentation. We improve precision and recall by up to 0.011, which corresponds to a reduction of the number of false positive and false negative detections by more than 3 per second. Furthermore, we show how our proposed image stacking approach can be implemented efficiently.

Fluxons in long and annular intrinsic Josephson junction stacks

CERN Document Server

Clauss, T; Moessle, M; Müller, A; Weber, A; Kölle, D; Kleiner, R

2002-01-01

A promising approach towards a THz oscillator based on intrinsic Josephson junctions in high-temperature superconductors is based on the collective motion of Josephson fluxons, which are predicted to form various configurations ranging from a triangular to a quadratic lattice. Not only for this reason, but certainly also for the sake of basic physics, several experimental and theoretical investigations have been done on the subject of collective fluxon dynamics in stacked intrinsic Josephson junctions. In this paper we will present some experimental results on the fluxon dynamics of long intrinsic Josephson junction stacks made of Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8. The stacks were formed either in an open or in an annular geometry, and clear resonant fluxon modes were observed. Experiments discussed include measurements of current-voltage characteristics in external magnetic fields and in external microwave fields.

Image transfer by cascaded stack of photonic crystal and air layers

NARCIS (Netherlands)

Shen, C.; Michielsen, K.; Raedt, H. De

2006-01-01

We demonstrate image transfer by a cascaded stack consisting of two and three triangular-lattice photonic crystal slabs separated by air. The quality of the image transfered by the stack is sensitive to the air/photonic crystal interface termination and the frequency. Depending on the frequency and

Influence factors of the inter-nanowire thermal contact resistance in the stacked nanowires

Science.gov (United States)

Wu, Dongxu; Huang, Congliang; Zhong, Jinxin; Lin, Zizhen

2018-05-01

The inter-nanowire thermal contact resistance is important for tuning the thermal conductivity of a nanocomposite for thermoelectric applications. In this paper, the stacked copper nanowires are applied for studying the thermal contact resistance. The stacked copper nanowires are firstly made by the cold-pressing method, and then the nanowire stacks are treated by sintering treatment. With the effect of the volumetric fraction of nanowires in the stack and the influence of the sintering-temperature on the thermal contact resistance discussed, results show that: The thermal conductivity of the 150-nm copper nanowires can be enlarged almost 2 times with the volumetric fraction increased from 32 to 56% because of the enlarged contact-area and contact number of a copper nanowire. When the sintering temperature increases from 293 to 673 K, the thermal conductivity of the stacked 300-nm nanowires could be enlarged almost 2.5 times by the sintering treatment, because of the improved lattice property of the contact zone. In conclusion, application of a high volumetric fraction or/and a sintering-treatment are effectivity to tune the inter-nanowire thermal contact resistance, and thus to tailor the thermal conductivity of a nanowire network or stack.

Assessment of the seismic resistance of a ventilation stack on a reactor building

International Nuclear Information System (INIS)

Makovicka, Daniel; Makovicka, Daniel

2005-01-01

The paper analyzes the seismic resistance of a ventilation stack on a reactor building, including the possible reserves of increasing the resistance. Structures of this type are highly sensitive to seismic loads, as the tuning of the stack (the spectrum of its lowest natural frequencies) corresponds with the frequency spectrum of excitation due to seismic effects. The purpose of the paper is to present an example of an actual structure to show the character of the response of the structure, and the participation of the individual frequency components of the response in the overall stress and strain state of a structure of this type. The methodology for a numerical analysis of the structure is also given. The load of the stack proper is modified by the transfer characteristics of the building. In engineering practice, the system is usually divided into two subsystems: the building with the sub-base, and the stack proper. The level of justification for the application of this simplification depends on the distance of the natural frequencies of the stack from the natural frequencies of the building. Finally, the paper deals with possible errors in determining the actual seismic resistance of the stack structure

Long-term operation of a solid oxide cell stack for coelectrolysis of steam and CO2

DEFF Research Database (Denmark)

Agersted, Karsten; Chen, Ming; Blennow, Peter

2016-01-01

of synthetic fuels such as methane, methanol or DME. Previously we have reported electrolysis operation of solid oxide cell stacks for periods up to about 1000 hours. In this work, operation of a Haldor Topsoe 8-cell stack (stack design of 2014) in co-electrolysis mode for 6000 hours is reported. The stack....... Initial operation at 700 oC and -0.25 A/cm2 lasted for only 120 hours due to severe degradation of the bottom cell. Regaining the stack performance was realized by increasing the operation temperature to 750 oC. After reactivation, the stack showed negligible degradation at 750 oC and -0.25 A/cm2...... and about 1.4 %/1000 h performance degradation at 750 oC and -0.5 A/cm2. This study demonstrates feasibility of long-term co-electrolysis operation via SOEC stacks and of careful temperature variation as a tool to regain the stack performance....

Linear identification and model adjustment of a PEM fuel cell stack

Energy Technology Data Exchange (ETDEWEB)

Kunusch, C; Puleston, P F; More, J J [LEICI, Departamento de Electrotecnia, Universidad Nacional de La Plata, calle 1 esq. 47 s/n, 1900 La Plata (Argentina); Consejo de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Husar, A [Institut de Robotica i Informatica Industrial (CSIC-UPC), c/ Llorens i Artigas 4-6, 08028 Barcelona (Spain); Mayosky, M A [LEICI, Departamento de Electrotecnia, Universidad Nacional de La Plata, calle 1 esq. 47 s/n, 1900 La Plata (Argentina); Comision de Investigaciones Cientificas (CIC), Provincia de Buenos Aires (Argentina)

2008-07-15

In the context of fuel cell stack control a mayor challenge is modeling the interdependence of various complex subsystem dynamics. In many cases, the states interaction is usually modeled through several look-up tables, decision blocks and piecewise continuous functions. Many internal variables are inaccessible for measurement and cannot be used in control algorithms. To make significant contributions in this area, it is necessary to develop reliable models for control and design purposes. In this paper, a linear model based on experimental identification of a 7-cell stack was developed. The procedure followed to obtain a linear model of the system consisted in performing spectroscopy tests of four different single-input single-output subsystems. The considered inputs for the tests were the stack current and the cathode oxygen flow rate, while the measured outputs were the stack voltage and the cathode total pressure. The resulting model can be used either for model-based control design or for on-line analysis and errors detection. (author)

Spherical distribution structure of the semiconductor laser diode stack for pumping

International Nuclear Information System (INIS)

Zhao Tianzhuo; Yu Jin; Liu Yang; Zhang Xue; Ma Yunfeng; Fan Zhongwei

2011-01-01

A semiconductor laser diode stack is used for pumping and 8 semiconductor laser diode arrays of the stack are put on a sphere, and the output of every bar is specially off-axis compressed to realize high coupling efficiency. The output beam of this semiconductor laser diode stack is shaped by a hollow duct to the laser active medium. The efficiency of the hollow light pipe, which is used for semiconductor laser diode stack coupling, is analyzed by geometric optics and ray tracing. Geometric optics analysis diagnoses the reasons for coupling loss and guides the design of the structure. Ray tracing analyzes the relation between the structural parameters and the output characteristics of this pumping system, and guides parameter optimization. Simulation and analysis results show that putting the semiconductor laser diode arrays on a spherical surface can increase coupling efficiency, reduce the optimum duct length and improve the output energy field distribution. (semiconductor devices)

Simulation and resolution of voltage reversal in microbial fuel cell stack.

Science.gov (United States)

Sugnaux, Marc; Savy, Cyrille; Cachelin, Christian Pierre; Hugenin, Gérald; Fischer, Fabian

2017-08-01

To understand the biotic and non-biotic contributions of voltage reversals in microbial fuel cell stacks (MFC) they were simulated with an electronic MFC-Stack mimic. The simulation was then compared with results from a real 3L triple MFC-Stack with shared anolyte. It showed that voltage reversals originate from the variability of biofilms, but also the external load plays a role. When similar biofilm properties were created on all anodes the likelihood of voltage reversals was largely reduced. Homogenous biofilms on all anodes were created by electrical circuit alternation and electrostimulation. Conversely, anolyte recirculation, or increased nutriment supply, postponed reversals and unfavourable voltage asymmetries on anodes persisted. In conclusion, voltage reversals are often a negative event but occur also in close to best MFC-Stack performance. They were manageable and this with a simplified MFC architecture in which multiple anodes share the same anolyte. Copyright © 2017 Elsevier Ltd. All rights reserved.

Batch Image Encryption Using Generated Deep Features Based on Stacked Autoencoder Network

Directory of Open Access Journals (Sweden)

Fei Hu

2017-01-01

Full Text Available Chaos-based algorithms have been widely adopted to encrypt images. But previous chaos-based encryption schemes are not secure enough for batch image encryption, for images are usually encrypted using a single sequence. Once an encrypted image is cracked, all the others will be vulnerable. In this paper, we proposed a batch image encryption scheme into which a stacked autoencoder (SAE network was introduced to generate two chaotic matrices; then one set is used to produce a total shuffling matrix to shuffle the pixel positions on each plain image, and another produces a series of independent sequences of which each is used to confuse the relationship between the permutated image and the encrypted image. The scheme is efficient because of the advantages of parallel computing of SAE, which leads to a significant reduction in the run-time complexity; in addition, the hybrid application of shuffling and confusing enhances the encryption effect. To evaluate the efficiency of our scheme, we compared it with the prevalent “logistic map,” and outperformance was achieved in running time estimation. The experimental results and analysis show that our scheme has good encryption effect and is able to resist brute-force attack, statistical attack, and differential attack.

Element stacking method for topology optimization with material-dependent boundary and loading conditions

DEFF Research Database (Denmark)

Yoon, Gil Ho; Park, Y.K.; Kim, Y.Y.

2007-01-01

A new topology optimization scheme, called the element stacking method, is developed to better handle design optimization involving material-dependent boundary conditions and selection of elements of different types. If these problems are solved by existing standard approaches, complicated finite...... element models or topology optimization reformulation may be necessary. The key idea of the proposed method is to stack multiple elements on the same discretization pixel and select a single or no element. In this method, stacked elements on the same pixel have the same coordinates but may have...... independent degrees of freedom. Some test problems are considered to check the effectiveness of the proposed stacking method....

Multistage Force Amplification of Piezoelectric Stacks

Science.gov (United States)

Xu, Tian-Bing (Inventor); Siochi, Emilie J. (Inventor); Zuo, Lei (Inventor); Jiang, Xiaoning (Inventor); Kang, Jin Ho (Inventor)

2015-01-01

Embodiments of the disclosure include an apparatus and methods for using a piezoelectric device, that includes an outer flextensional casing, a first cell and a last cell serially coupled to each other and coupled to the outer flextensional casing such that each cell having a flextensional cell structure and each cell receives an input force and provides an output force that is amplified based on the input force. The apparatus further includes a piezoelectric stack coupled to each cell such that the piezoelectric stack of each cell provides piezoelectric energy based on the output force for each cell. Further, the last cell receives an input force that is the output force from the first cell and the last cell provides an output apparatus force In addition, the piezoelectric energy harvested is based on the output apparatus force. Moreover, the apparatus provides displacement based on the output apparatus force.

Development of the elementary technology and the stack manufacturing process of solid oxide fuel cell (II)

Energy Technology Data Exchange (ETDEWEB)

Hong, S.A.; Seo, I.Y.; Lee, S.H. [Ssangyong Research Center (Korea, Republic of)] [and others

1996-02-01

Most of the SOFC components are composed of ceramics. Energy efficiency of SOFC can be obtained up to 80% with co-generation system and is higher than the traditional electricity generation system (30%). SOFC has having highest efficient among the several fuel cell system and is called {sup T}he 3 rd Generation Fuel Cell`. So the every developed countries are competing to develop this high technology. Key points to develop SOFCs are to select a materials having the similar thermal expansion behaviors and to construct a stable design. At present, three common stack configurations have been proposed and fabricated for SOFCs : sealess tubular design, flat-plat design, monolithic design. Although having disadvantages in the stability of performance and structure, the flat-plate design is commonly adopted rather than tubular design in recent SOFC R and D because of economical merit of commercial scale fabrication. In this study flat-plat design is adopted to develop SOFC in this study. The purpose of this study, the 2 nd year of Phase I, was to apply and progress the fabrication technology of 5 x 5 cm{sup 2} sized unit cell that was developed in 1 st year and to develop elementary technologies of stack manufacturing, i. e., design and fabrication of separator, sealing materials and gas sealing technology. (author) 66 refs., 48 tabs., 195 figs.

The use of Graphic User Interface for development of a user-friendly CRS-Stack software

Science.gov (United States)

Sule, Rachmat; Prayudhatama, Dythia; Perkasa, Muhammad D.; Hendriyana, Andri; Fatkhan; Sardjito; Adriansyah

2017-04-01

The development of a user-friendly Common Reflection Surface (CRS) Stack software that has been built by implementing Graphical User Interface (GUI) is described in this paper. The original CRS-Stack software developed by WIT Consortium is compiled in the unix/linux environment, which is not a user-friendly software, so that a user must write the commands and parameters manually in a script file. Due to this limitation, the CRS-Stack become a non popular method, although applying this method is actually a promising way in order to obtain better seismic sections, which have better reflector continuity and S/N ratio. After obtaining successful results that have been tested by using several seismic data belong to oil companies in Indonesia, it comes to an idea to develop a user-friendly software in our own laboratory. Graphical User Interface (GUI) is a type of user interface that allows people to interact with computer programs in a better way. Rather than typing commands and module parameters, GUI allows the users to use computer programs in much simple and easy. Thus, GUI can transform the text-based interface into graphical icons and visual indicators. The use of complicated seismic unix shell script can be avoided. The Java Swing GUI library is used to develop this CRS-Stack GUI. Every shell script that represents each seismic process is invoked from Java environment. Besides developing interactive GUI to perform CRS-Stack processing, this CRS-Stack GUI is design to help geophysicists to manage a project with complex seismic processing procedures. The CRS-Stack GUI software is composed by input directory, operators, and output directory, which are defined as a seismic data processing workflow. The CRS-Stack processing workflow involves four steps; i.e. automatic CMP stack, initial CRS-Stack, optimized CRS-Stack, and CRS-Stack Supergather. Those operations are visualized in an informative flowchart with self explanatory system to guide the user inputting the

Modelling and Evaluation of Heating Strategies for High Temperature Polymer Electrolyte Membrane Fuel Cell Stacks

DEFF Research Database (Denmark)

Andreasen, Søren Juhl; Kær, Søren Knudsen

2008-01-01

Experiments were conducted on two different cathode air cooled high temperature PEM (HTPEM) fuel cell stacks; a 30 cell 400W prototype stack using two bipolar plates per cell, and a 65 cell 1 kW commercial stack using one bipolar plate per cell. The work seeks to examine the use of different...... model to simulate the temperature development of a fuel cell stack during heating can be used for assistance in system and control design. The heating strategies analyzed and tested reduced the startup time of one of the fuel cell stacks from 1 h to about 6 min....

The crystal structure of baliczunicite, Bi₂O(SO₄)₂, a new natural bismuth oxide sulfate

DEFF Research Database (Denmark)

Pinto, Daniela; Garavelli, Anna; Balic Zunic, Tonci

2015-01-01

parallel to the (100) plane. The planes are stacked atom on atom such that Bi always overlays S and vice versa. This structural feature is shared with the known structure of the high-temperature polymorph of the same compound, stable at T >535oC. However, the sequences of Bi and S atoms in the two...

Complex cobordism and stable homotopy groups of spheres

CERN Document Server

Ravenel, Douglas C

2003-01-01

Since the publication of its first edition, this book has served as one of the few available on the classical Adams spectral sequence, and is the best account on the Adams-Novikov spectral sequence. This new edition has been updated in many places, especially the final chapter, which has been completely rewritten with an eye toward future research in the field. It remains the definitive reference on the stable homotopy groups of spheres. The first three chapters introduce the homotopy groups of spheres and take the reader from the classical results in the field though the computational aspects

Facies architecture and high resolution sequence stratigraphy of an aeolian, fluvial and shallow marine system in the Pennsylvanian Piauí Formation, Parnaíba Basin, Brazil

Science.gov (United States)

Vieira, Lucas Valadares; Scherer, Claiton Marlon dos Santos

2017-07-01

The Pennsylvanian Piauí Formation records the deposition of aeolian, fluvial and shallow marine systems accumulated in the cratonic sag Parnaíba basin. Characterization of the facies associations and sequence stratigraphic framework was done by detailed description and logging of outcrops. Six facies associations were recognized: aeolian dunes and interdunes, aeolian sandsheets, fluvial channels, tidally-influenced fluvial channels, shoreface and shoreface-shelf transition. Through correlation of stratigraphic surfaces, the facies associations were organized in system tracts, which formed eight high frequency depositional sequences, bounded by subaerial unconformities. These sequences are composed of a lowstand system tract (LST), that is aeolian-dominated or fluvial-dominated, a transgressive system tract (TST) that is formed by tidally-influenced fluvial channels and/or shoreface and shoreface-shelf transition deposits with retrogradational stacking, and a highstand system tract (HST), which is formed by shoreface-shelf transition and shoreface deposits with progradational stacking. Two low frequency cycles were determined by observing the stacking of the high frequency cycles. The Lower Sequence is characterized by aeolian deposits of the LST and an aggradational base followed by a progressive transgression, defining a general TST. The Upper Sequence is characterized by fluvial deposits and interfluve pedogenesis concurring with the aeolian deposits of the LST and records a subtle regression followed by transgression. The main control on sedimentation in the Piauí Formation was glacioeustasy, which was responsible for the changes in relative sea level. Even though, climate changes were associated with glacioeustatic phases and influenced the aeolian and fluvial deposition.

Solid-state dewetting of single- and bilayer Au-W thin films: Unraveling the role of individual layer thickness, stacking sequence and oxidation on morphology evolution

Directory of Open Access Journals (Sweden)

A. Herz

2016-03-01

Full Text Available Self-assembly of ultrathin Au, W, and Au-W bilayer thin films is investigated using a rapid thermal annealing technique in an inert ambient. The solid-state dewetting of Au films is briefly revisited in order to emphasize the role of initial film thickness. W films deposited onto SiO2 evolve into needle-like nanocrystals rather than forming particle-like agglomerates upon annealing at elevated temperatures. Transmission electron microscopy reveals that such nanocrystals actually consist of tungsten (VI oxide (WO3 which is related to an anisotropic oxide crystal growth out of the thin film. The evolution of W films is highly sensitive to the presence of any residual oxygen. Combination of both the dewetting of Au and the oxide crystal growth of WO3 is realized by using various bilayer film configurations of the immiscible Au and W. At low temperature, Au dewetting is initiated while oxide crystal growth is still suppressed. Depending on the stacking sequence of the Au-W bilayer thin film, W acts either as a substrate or as a passivation layer for the dewetting of Au. Being the ground layer, W changes the wettability of Au which clearly modifies its initial state for the dewetting. Being the top layer, W prevents Au from dewetting regardless of Au film thickness. Moreover, regular pattern formation of Au-WO3 nanoparticles is observed at high temperature demonstrating how bilayer thin film dewetting can create unique nanostructure arrangements.

Solid-state dewetting of single- and bilayer Au-W thin films: Unraveling the role of individual layer thickness, stacking sequence and oxidation on morphology evolution

Energy Technology Data Exchange (ETDEWEB)

Herz, A., E-mail: andreas.herz@tu-ilmenau.de, E-mail: dong.wang@tu-ilmenau.de; Franz, A.; Theska, F.; Hentschel, M.; Kups, Th.; Wang, D., E-mail: andreas.herz@tu-ilmenau.de, E-mail: dong.wang@tu-ilmenau.de; Schaaf, P. [Department of Materials for Electronics and Electrical Engineering, Institute of Materials Science and Engineering and Institute of Micro- and Nanotechnologies MacroNano, TU Ilmenau, D-98693 Ilmenau (Germany)

2016-03-15

Self-assembly of ultrathin Au, W, and Au-W bilayer thin films is investigated using a rapid thermal annealing technique in an inert ambient. The solid-state dewetting of Au films is briefly revisited in order to emphasize the role of initial film thickness. W films deposited onto SiO{sub 2} evolve into needle-like nanocrystals rather than forming particle-like agglomerates upon annealing at elevated temperatures. Transmission electron microscopy reveals that such nanocrystals actually consist of tungsten (VI) oxide (WO{sub 3}) which is related to an anisotropic oxide crystal growth out of the thin film. The evolution of W films is highly sensitive to the presence of any residual oxygen. Combination of both the dewetting of Au and the oxide crystal growth of WO{sub 3} is realized by using various bilayer film configurations of the immiscible Au and W. At low temperature, Au dewetting is initiated while oxide crystal growth is still suppressed. Depending on the stacking sequence of the Au-W bilayer thin film, W acts either as a substrate or as a passivation layer for the dewetting of Au. Being the ground layer, W changes the wettability of Au which clearly modifies its initial state for the dewetting. Being the top layer, W prevents Au from dewetting regardless of Au film thickness. Moreover, regular pattern formation of Au-WO{sub 3} nanoparticles is observed at high temperature demonstrating how bilayer thin film dewetting can create unique nanostructure arrangements.

A “4-cell” modular passive DMFC (direct methanol fuel cell) stack for portable applications

International Nuclear Information System (INIS)

Wang, Luwen; He, Mingyan; Hu, Yue; Zhang, Yufeng; Liu, Xiaowei; Wang, Gaofeng

2015-01-01

A “4-cell” modular passive DMFC (direct methanol fuel cell) stack, which can be freely combined and applied to various electronic devices, is designed, fabricated and tested. Two PCB (printed circuit board) based accessories are designed and fabricated for electrically connecting and mechanically assembling the “4-cell” modules. The maximum power density of the “4-cell” module is 27 mW cm −2 at 5 M methanol concentration. The steady-state performances of the modular stacks with different numbers of modules are tested. The extra power loss of the multiple module stacks due to inter-module electrical connections is predicted by mathematical fitting method. The fitting results indicate that the efficiencies of the multiple module stacks are all above 90% up to 10 modules. The dynamic performances of the modular stacks are also investigated for portable applications. The results show that the modular stacks exhibit good responsiveness and reproducibility at high loading current (>100 mA). Finally, the modular stacks are successfully applied to drive the experimental fan and charge the mobile phone. - Highlights: • A “4-cell” modular passive DMFC (direct methanol fuel cell) stack is designed, fabricated and tested. • This modular DMFC stack can assemble more single cells with high efficiency. • The modular stack exhibit good responsiveness and reproducibility for portable application

OpenStack Object Storage (Swift) essentials

CERN Document Server

Kapadia, Amar; Varma, Sreedhar

2015-01-01

If you are an IT administrator and you want to enter the world of cloud storage using OpenStack Swift, then this book is ideal for you. Basic knowledge of Linux and server technology is beneficial to get the most out of the book.

Heuristic Solution Approaches to the Double TSP with Multiple Stacks

DEFF Research Database (Denmark)

Petersen, Hanne Løhmann

This paper introduces the Double Travelling Salesman Problem with Multiple Stacks and presents a three different metaheuristic approaches to its solution. The Double Travelling Salesman Problem with Multiple Stacks is concerned with finding the shortest route performing pickups and deliveries in ...... are developed for the problem and used with each of the heuristics. Finally some computational results are given along with lower bounds on the objective value....

Heuristic Solution Approaches to the Double TSP with Multiple Stacks

DEFF Research Database (Denmark)

Petersen, Hanne Løhmann

2006-01-01

This paper introduces the Double Travelling Salesman Problem with Multiple Stacks and presents a three different metaheuristic approaches to its solution. The Double Travelling Salesman Problem with Multiple Stacks is concerned with finding the shortest route performing pickups and deliveries in ...... are developed for the problem and used with each of the heuristics. Finally some computational results are given along with lower bounds on the objective value....

Lower power by voltage stacking : a fine-grained system design approach

NARCIS (Netherlands)

Blutman, K.; Kapoor, A.; Martinez, J.G.; Fatemi, S.H.; Pineda de Gyvez, J.

2016-01-01

Stacking voltage domains on top of each other is a design approach that is getting the attention of engineering communities due to the implicit high efficiency of the power delivery. Previous works have shown voltage stacking at the core level only. In this paper we present a more involved approach

Test Plan for Long-Term Operation of a Ten-Cell High Temperature Electrolysis Stack

International Nuclear Information System (INIS)

James E. O'Brien; Carl M. Stoots; J. Stephen Herring

2008-01-01

This document defines a test plan for a long-term (2500 Hour) test of a ten-cell high-temperature electrolysis stack to be performed at INL during FY09 under the Nuclear Hydrogen Initiative. This test was originally planned for FY08, but was removed from our work scope as a result of the severe budget cuts in the FY08 NHI Program. The purpose of this test is to evaluate stack performance degradation over a relatively long time period and to attempt to identify some of the degradation mechanisms via post-test examination. This test will be performed using a planar ten-cell Ceramatec stack, with each cell having dimensions of 10 cm x 10 cm. The specific makeup of the stack will be based on the results of a series of shorter duration ten-cell stack tests being performed during FY08, funded by NGNP. This series of tests was aimed at evaluating stack performance with different interconnect materials and coatings and with or without brazed edge rails. The best performing stack from the FY08 series, in which five different interconnect/coating/edge rail combinations were tested, will be selected for the FY09 long-term test described herein

DNA partitions into triplets under tension in the presence of organic cations, with sequence evolutionary age predicting the stability of the triplet phase

NARCIS (Netherlands)

Taghavi, Amirhossein; van der Schoot, Paul; Berryman, Joshua T

2017-01-01

Using atomistic simulations, we show the formation of stable triplet structure when particular GC-rich DNA duplexes are extended in solution over a timescale of hundreds of nanoseconds, in the presence of organic salt. We present planar-stacked triplet disproportionated DNA (Σ DNA) as a possible

The Influence of the Density of Coconut Fiber as Stack in Thermo-Acoustics Refrigeration System

Science.gov (United States)

Hartulistiyoso, E.; Yulianto, M.; Sucahyo, L.

2018-05-01

An experimental study of using coconut fiber as stack with varying density in thermo-acoustics refrigeration system has been done. Stack is a device which is described as the “heart” in thermo-acoustics refrigeration system. The length of stack is a fix parameter in this experiment. The performance of the coconut fiber was evaluated from the density of stack (varied from 30%, 50% and 70%), position of stack (varied from 0 to 34 cm from the sound generator), and frequency of sound generator (varied from 150 Hz, 200Hz, 250Hz and 300Hz). The inside, outside, and environment temperatures were collected every second using Data Acquisition (DAQ). The result showed that the increase of stack density will increase the performance of thermo-acoustics refrigeration system. The higher density produced temperature differences in cold side and hot side of 5.4°C. In addition, the position of stack and frequency of sound generator have an important role in the performance of thermo-acoustics refrigeration system for all variations of the density.

Dose assessment from potential radionuclide emissions from stacks on the Hanford Site

International Nuclear Information System (INIS)

Davis, W.E.; Barnett, J.M.

1995-04-01

On February 3, 1993, the US Department of Energy, Richland Operations Office (RL), received a Compliance Order and Information Request from the Director of the Air and Toxics Division of the US Environmental Protection Agency (EPA), Region 10. The Compliance Order required RL to (1) evaluate all radionuclide emission points at the Hanford Site to determine which points are subject to the continuous emission sampling requirements of Title 40, Code of Federal Regulations, Part 61 (40 CFR 61), Subpart H, and (2) continuously sample radionuclide emissions in accordance with requirements in 40 CFR 61.93. The Information Request required RL to provide a written Compliance Plan to meet the requirements of the Compliance Order. A Compliance Plan was submitted to EPA, Region 10, on April 30, 1993. The Compliance Plan specified that a dose assessment would be performed for 84 Westinghouse Hanford Company (WHC) stacks registered with the Washington State Department of Health on the Hanford Site. Any stack identified in the assessment as having potential emissions to cause an effective dose equivalent (EDE) to a maximum exposed individual (MEI) greater than 0.1 mrem y -1 must have a compliant sampling system. In addition, a Federal Facility Compliance Agreement (FFCA) was signed on. February 7, 1994. The FFCA required that all unregistered stacks on the Hanford Site be assessed. This requirement increased the number of stacks to be assessed to 123 stacks. Six methods for performing the assessments are described. An initial assessment using only the HEPA filtration factor for back calculations identified 32 stacks that would have emissions which would cause an EDE to the MEI greater than 0.1 mrem y -1 . When the other methods were applied the number was reduced to 20 stacks. The paper discusses reasons for these overestimates

Single-Event Transgene Product Levels Predict Levels in Genetically Modified Breeding Stacks.

Science.gov (United States)

Gampala, Satyalinga Srinivas; Fast, Brandon J; Richey, Kimberly A; Gao, Zhifang; Hill, Ryan; Wulfkuhle, Bryant; Shan, Guomin; Bradfisch, Greg A; Herman, Rod A

2017-09-13

The concentration of transgene products (proteins and double-stranded RNA) in genetically modified (GM) crop tissues is measured to support food, feed, and environmental risk assessments. Measurement of transgene product concentrations in breeding stacks of previously assessed and approved GM events is required by many regulatory authorities to evaluate unexpected transgene interactions that might affect expression. Research was conducted to determine how well concentrations of transgene products in single GM events predict levels in breeding stacks composed of these events. The concentrations of transgene products were compared between GM maize, soybean, and cotton breeding stacks (MON-87427 × MON-89034 × DAS-Ø15Ø7-1 × MON-87411 × DAS-59122-7 × DAS-40278-9 corn, DAS-81419-2 × DAS-44406-6 soybean, and DAS-21023-5 × DAS-24236-5 × SYN-IR102-7 × MON-88913-8 × DAS-81910-7 cotton) and their component single events (MON-87427, MON-89034, DAS-Ø15Ø7-1, MON-87411, DAS-59122-7, and DAS-40278-9 corn, DAS-81419-2, and DAS-44406-6 soybean, and DAS-21023-5, DAS-24236-5, SYN-IR102-7, MON-88913-8, and DAS-81910-7 cotton). Comparisons were made within a crop and transgene product across plant tissue types and were also made across transgene products in each breeding stack for grain/seed. Scatter plots were generated comparing expression in the stacks to their component events, and the percent of variability accounted for by the line of identity (y = x) was calculated (coefficient of identity, I 2 ). Results support transgene concentrations in single events predicting similar concentrations in breeding stacks containing the single events. Therefore, food, feed, and environmental risk assessments based on concentrations of transgene products in single GM events are generally applicable to breeding stacks composed of these events.

Stacking gels: A method for maximising output for pulsed-field gel electrophoresis

Directory of Open Access Journals (Sweden)

Heng See

2009-01-01

Full Text Available Pulsed field gel electrophoresis (PFGE, the gold standard of molecular typing methods, has a major disadvantage of an unusually long electrophoretic time. From the original protocol of 6 days, it was modified to 3 days and subsequently to a single day. We describe the procedure of stacking five to six gels one on top of another in order to increase and maximize the output in a shorter time without compromising the resolution and reproducibility. All the variables that affect pulsed field gels during electrophoresis were taken into consideration. We firstly optimized the parameters to be used and secondly determined whether stacking of five to six gels had any effect on the molecular separation during electrophoresis in comparison with a single gel run. DNA preparation, restriction, electrophoresis, staining and gel documentation was carried out based on previously published methods. Gels were analysed using BioNumerics and dice coefficient and unweighted pair group methods were used to generate dendrograms based on 1.5% tolerance values. Identical band profiles and band resolution-separation were seen in the PFGE patterns with single gel and multiple stacking gels. Cluster analysis further strengthened the fact that results from stacking gels were reproducible and comparable with a single gel run. This method of stacking gels saves time and maximizes the output at the same time. The run time for a single gel was about 28 hours, but with six stacked gels the run time was 54 hours compared with 28 x 6 = 168 hours if they were run separately as single gels thus saving time of 67.86%. Beside the big factor of saving time, stacking gels save resources (electricity, reagents, water, chemicals and working time by increasing the sample throughput in a shorter time without compromising on quality of data. But optimization of working parameters is vital depending on the PFGE system used.

Density Functional Study of Stacking Structures and Electronic Behaviors of AnE-PV Copolymer.

Science.gov (United States)

Dong, Chuan-Ding; Beenken, Wichard J D

2016-10-10

In this work, we report an in-depth investigation on the π-stacking and interdigitating structures of poly(p-anthracene-ethynylene)-alt-poly(p-phenylene-vinylene) copolymer with octyl and ethyl-hexyl side chains and the resulting electronic band structures using density functional theory calculations. We found that in the π-stacking direction, the preferred stacking structure, determined by the steric effect of the branched ethyl-hexyl side chains, is featured by the anthracene-ethynylene units stacking on the phenylene-vinylene units of the neighboring chains and vice versa. This stacking structure, combined with the interdigitating structure where the branched side chains of the laterally neighboring chains are isolated, defines the energetically favorable structure of the ordered copolymer phase, which provides a good compromise between light absorption and charge-carrier transport.

Bipolarly stacked electrolyser for energy and space efficient fabrication of supercapacitor electrodes

Science.gov (United States)

Liu, Xiaojuan; Wu, Tao; Dai, Zengxin; Tao, Keran; Shi, Yong; Peng, Chuang; Zhou, Xiaohang; Chen, George Z.

2016-03-01

Stacked electrolysers with titanium bipolar plates are constructed for electrodeposition of polypyrrole electrodes for supercapacitors. The cathode side of the bipolar Ti plates are pre-coated with activated carbon. In this new design, half electrolysis occurs which significantly lowers the deposition voltage. The deposited electrodes are tested in a symmetrical unit cell supercapacitor and an asymmetrical supercapacitor stack. Both devices show excellent energy storage performances and the capacitance values are very close to the design value, suggesting a very high current efficiency during the electrodeposition. The electrolyser stack offers multi-fold benefits for preparation of conducting polymer electrodes, i.e. low energy consumption, facile control of the electrode capacitance and simultaneous preparation of a number of identical electrodes. Therefore, the stacked bipolar electrolyser is a technology advance that offers an engineering solution for mass production of electrodeposited conducting polymer electrodes for supercapacitors.

Stacked spheres and lower bound theorem

Indian Academy of Sciences (India)

BASUDEB DATTA

2011-11-20

Nov 20, 2011 ... Preliminaries. Lower bound theorem. On going work. Definitions. An n-simplex is a convex hull of n + 1 affinely independent points. (called vertices) in some Euclidean space R. N . Stacked spheres and lower bound theorem. Basudeb Datta. Indian Institute of Science. 2 / 27 ...

Contemporary sample stacking in analytical electrophoresis

Czech Academy of Sciences Publication Activity Database

Šlampová, Andrea; Malá, Zdeňka; Pantůčková, Pavla; Gebauer, Petr; Boček, Petr

2013-01-01

Roč. 34, č. 1 (2013), s. 3-18 ISSN 0173-0835 R&D Projects: GA ČR GAP206/10/1219 Institutional support: RVO:68081715 Keywords : biological samples * stacking * trace analysis * zone electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.161, year: 2013

Contemporary sample stacking in analytical electrophoresis

Czech Academy of Sciences Publication Activity Database

Malá, Zdeňka; Šlampová, Andrea; Křivánková, Ludmila; Gebauer, Petr; Boček, Petr

2015-01-01

Roč. 36, č. 1 (2015), s. 15-35 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : biological samples * stacking * trace analysis * zone electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.482, year: 2015

40 CFR 61.53 - Stack sampling.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.53 Section 61.53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Mercury ore processing facility. (1) Unless a waiver of emission testing is obtained under...

Toward advising SME's on stacked funding

NARCIS (Netherlands)

Rauwerda, Kirsten; van Teeffelen, Lex; de Graaf, Frank Jan

2017-01-01

This paper addresses new funding issues faced by SMEs. Over a period of nine months, the authors conducted a preliminary study into the problems surrounding stacked funding faced by SMEs and their financial advisers. The study includes a short literature review, the outcomes of three round table

Integrated fuel cell stack shunt current prevention arrangement

Energy Technology Data Exchange (ETDEWEB)

Roche, Robert P. (Cheshire, CT); Nowak, Michael P. (Bolton, CT)

1992-01-01

A fuel cell stack includes a plurality of fuel cells juxtaposed with one another in the stack and each including a pair of plate-shaped anode and cathode electrodes that face one another, and a quantity of liquid electrolyte present at least between the electrodes. A separator plate is interposed between each two successive electrodes of adjacent ones of the fuel cells and is unified therewith into an integral separator plate. Each integral separator plate is provided with a circumferentially complete barrier that prevents flow of shunt currents onto and on an outer peripheral surface of the separator plate. This barrier consists of electrolyte-nonwettable barrier members that are accommodated, prior to the formation of the integral separator plate, in corresponding edge recesses situated at the interfaces between the electrodes and the separator plate proper. Each barrier member extends over the entire length of the associated marginal portion and is flush with the outer periphery of the integral separator plate. This barrier also prevents cell-to-cell migration of any electrolyte that may be present at the outer periphery of the integral separator plate while the latter is incorporated in the fuel cell stack.

A microcontroller with 96% power-conversion efficiency using stacked voltage domains

NARCIS (Netherlands)

Blutman, K.; Kapoor, A.; Majumdar, A.; Martinez, J.G.; Echeverri, J.; Sevat, L.; Van Der Wel, A.; Fatemi, H.; Pineda de Gyvez, J.; Makinwa, K.

2016-01-01

This paper presents a CMOS 40nm microcontroller where for the first time, stacked voltage domains are used. The system features an ARM Cortex M0+ processor, 4kB ROM, 16kB SRAM, peripherals, and an on-chip switched-capacitor voltage regulator (SCVR). By using voltage stacking the test chip achieves

Docker on OpenStack

OpenAIRE

Agarwal, Nitin; Moreira, Belmiro

2014-01-01

Project Specification CERN is establishing a large scale private cloud based on OpenStack as part of the expansion of the computing infrastructure for storing the data coming out of the Large Hadron Collider (LHC) experiments. As the data coming out of the detectors is increasing continuously that needs to be stored in the data center, we need more physical resources (more money) and since Virtual machines takes lot of CPU and memory overhead and minutes for creating the images, booting u...

Quality Assurance of Solid Oxide Fuel Cell (SOFC) and Electrolyser (SOEC) Stacks

DEFF Research Database (Denmark)

Lang, Michael; Auer, Corinna; Couturier, Karine

2017-01-01

In the EU-funded project “Solid oxide cell and stack testing and quality assurance” (SOCTESQA) standardized and industry wide test modules and programs for high temperature solid oxide cells and stacks are being developed. These test procedures can be applied for the fuel cell (SOFC......), the electrolysis (SOEC) and in the combined SOFC/SOEC mode. In order to optimize the test modules the project partners have tested identical SOC stacks with the same test programs in several testing campaigns. Altogether 10 pre-normative test modules were developed: Start-up, current-voltage characteristics...

Development of on-site PAFC stacks

Energy Technology Data Exchange (ETDEWEB)

Hotta, K.; Matsumoto, Y. [Kansai Electric Power Co., Amagasaki (Japan); Horiuchi, H.; Ohtani, T. [Mitsubishi Electric Corp., Kobe (Japan)

1996-12-31

PAFC (Phosphoric Acid Fuel Cell) has been researched for commercial use and demonstration plants have been installed in various sites. However, PAFC don`t have a enough stability yet, so more research and development must be required in the future. Especially, cell stack needs a proper state of three phases (liquid, gas and solid) interface. It is very difficult technology to keep this condition for a long time. In the small size cell with the electrode area of 100 cm{sup 2}, gas flow and temperature distributions show uniformity. But in the large size cell with the electrode area of 4000 cm{sup 2}, the temperature distributions show non-uniformity. These distributions would cause to be shorten the cell life. Because these distributions make hot-spot and gas poverty in limited parts. So we inserted thermocouples in short-stack for measuring three-dimensional temperature distributions and observed effects of current density and gas utilization on temperature.

Experimental 1 kW 20 cell PEFC stack

Energy Technology Data Exchange (ETDEWEB)

Buechi, F N; Marmy, C A; Scherer, G G [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ruge, M [Swiss Federal Inst. of Technology (ETH), Zuerich (Switzerland)

1999-08-01

A 20-cell PEFC stack was designed and built. Resin impregnated graphite was used as bipolar plate material. The air cooling of the stack was optimized by introducing high surface structures into the open space of the cooling plates. At {eta} (H{sub 2} LHV) = 0.5 a power of 880 W was obtained under conditions of low gas-pressures of 1.15 bar{sub a}. The auxiliary power for process air supply and cooling at 880 W power is less than 7% of the power output, indicating that the described system may be operated at a high efficiency. (author) 5 figs., 2 refs.

Rapid subsidence and stacked Gilbert-type fan deltas, Pliocene Loreto basin, Baja California Sur, Mexico

Science.gov (United States)

Dorsey, Rebecca J.; Umhoefer, Paul J.; Renne, Paul R.

1995-08-01

Pliocene nonmarine to marine sedimentary rocks exposed in the Loreto basin, Baja California Sur, provide a record of syntectonic subsidence and sedimentation in a transform-rift basin that developed along the western margin of the Gulf of California. A thick sequence of twelve Gilbert-type fan deltas, having a total measured thickness of about 615 m, accumulated near the fault-bounded southwestern margin of this basin. Based on stratal geometries and lithofacies associations, sedimentary rocks are divided into Gilbert-delta topset, foreset and bottomset strata, shell beds and background shallow-marine shelf deposits. Topset strata of each Gilbert-type delta cycle are capped by laterally persistent molluscan shell beds containing diverse assemblages of bivalves, pectens, oysters, gastropods and echinoids. These shell beds are interpreted to be condensed intervals that record sediment starvation during abandonment of the fan-delta plain. Delta abandonment may have been caused by large episodic faulting events, which submerged each pre-existing fan-delta plain, substantially slowed detrital input by drowning of alluvial feeder channels, and created new accommodation space for each new Gilbert-type fan delta. Alternatively, it is possible that delta-plain abandonment was caused by upstream avulsions and autocyclic lateral switching of fan-delta lobes during relatively uniform rates of slip along the basin-bounding fault. Two contrasting, plausible basin models are proposed for the Loreto basin: (1) asymmetric subsidence along a high-angle oblique-slip normal fault, producing a classic half-graben basin geometry with vertically stacked Gilbert-type fan deltas; or (2) lateral stacking and horizontal displacement of strata away from a relatively fixed depocenter due to fault movement in the releasing bend of a listric strike-slip fault. We favor the first model because field relations and simple geometric constraints suggest that most of the total measured section

Modeling of a Stacked Power Module for Parasitic Inductance Extraction

Science.gov (United States)

2017-09-15

ARL-TR-8138 ● SEP 2017 US Army Research Laboratory Modeling of a Stacked Power Module for Parasitic Inductance Extraction by...not return it to the originator. ARL-TR-8138 ● SEP 2017 US Army Research Laboratory Modeling of a Stacked Power Module for... Power Module for Parasitic Inductance Extraction 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Steven Kaplan

Protein-based stable isotope probing.

Science.gov (United States)

Jehmlich, Nico; Schmidt, Frank; Taubert, Martin; Seifert, Jana; Bastida, Felipe; von Bergen, Martin; Richnow, Hans-Hermann; Vogt, Carsten

2010-12-01

We describe a stable isotope probing (SIP) technique that was developed to link microbe-specific metabolic function to phylogenetic information. Carbon ((13)C)- or nitrogen ((15)N)-labeled substrates (typically with >98% heavy label) were used in cultivation experiments and the heavy isotope incorporation into proteins (protein-SIP) on growth was determined. The amount of incorporation provides a measure for assimilation of a substrate, and the sequence information from peptide analysis obtained by mass spectrometry delivers phylogenetic information about the microorganisms responsible for the metabolism of the particular substrate. In this article, we provide guidelines for incubating microbial cultures with labeled substrates and a protocol for protein-SIP. The protocol guides readers through the proteomics pipeline, including protein extraction, gel-free and gel-based protein separation, the subsequent mass spectrometric analysis of peptides and the calculation of the incorporation of stable isotopes into peptides. Extraction of proteins and the mass fingerprint measurements of unlabeled and labeled fractions can be performed in 2-3 d.

Numerical investigation of thermal behaviors in lithium-ion battery stack discharge

International Nuclear Information System (INIS)

Liu, Rui; Chen, Jixin; Xun, Jingzhi; Jiao, Kui; Du, Qing

2014-01-01

Highlights: • The thermal behaviors of a Li-ion battery stack have been investigated by modeling. • Parametric studies have been performed focusing on three different cooling materials. • Effects of discharge rate, ambient temperature and Reynolds number are examined. • General guidelines are proposed for the thermal management of a Li-ion battery stack. - Abstract: Thermal management is critically important to maintain the performance and prolong the lifetime of a lithium-ion (Li-ion) battery. In this paper, a two-dimensional and transient model has been developed for the thermal management of a 20-flat-plate-battery stack, followed by comprehensive numerical simulations to study the influences of ambient temperature, Reynolds number, and discharge rate on the temperature distribution in the stack with different cooling materials. The simulation results indicate that liquid cooling is generally more effective in reducing temperature compared to phase-change material, while the latter can lead to more homogeneous temperature distribution. Fast and deep discharge should be avoided, which generally yields high temperature beyond the acceptable range regardless of cooling materials. At low or even subzero ambient temperatures, air cooling is preferred over liquid cooling because heat needs to be retained rather than removed. Such difference becomes small when the ambient temperature increases to a mild level. The effects of Reynolds number are apparent in liquid cooling but negligible in air cooling. Choosing appropriate cooling material and strategy is particularly important in low ambient temperature and fast discharge cases. These findings improve the understanding of battery stack thermal behaviors and provide the general guidelines for thermal management system. The present model can also be used in developing control system to optimize battery stack thermal behaviors

Stack Characterization in CryoSat Level1b SAR/SARin Baseline C

Science.gov (United States)

Scagliola, Michele; Fornari, Marco; Di Giacinto, Andrea; Bouffard, Jerome; Féménias, Pierre; Parrinello, Tommaso

2015-04-01

CryoSat was launched on the 8th April 2010 and is the first European ice mission dedicated to the monitoring of precise changes in the thickness of polar ice sheets and floating sea ice. CryoSat is the first altimetry mission operating in SAR mode and it carries an innovative radar altimeter called the Synthetic Aperture Interferometric Altimeter (SIRAL), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. The current CryoSat IPF (Instrument Processing Facility), Baseline B, was released in operation in February 2012. After more than 2 years of development, the release in operations of the Baseline C is expected in the first half of 2015. It is worth recalling here that the CryoSat SAR/SARin IPF1 generates 20Hz waveforms in correspondence of an approximately equally spaced set of ground locations on the Earth surface, i.e. surface samples, and that a surface sample gathers a collection of single-look echoes coming from the processed bursts during the time of visibility. Thus, for a given surface sample, the stack can be defined as the collection of all the single-look echoes pointing to the current surface sample, after applying all the necessary range corrections. The L1B product contains the power average of all the single-look echoes in the stack: the multi-looked L1B waveform. This reduces the data volume, while removing some information contained in the single looks, useful for characterizing the surface and modelling the L1B waveform. To recover such information, a set of parameters has been added to the L1B product: the stack characterization or beam behaviour parameters. The stack characterization, already included in previous Baselines, has been reviewed and expanded in Baseline C. This poster describes all the stack characterization parameters, detailing what they represent and how they have been computed. In details, such parameters can be summarized in: - Stack

System for inspection of stacked cargo containers

Science.gov (United States)

Derenzo, Stephen [Pinole, CA

2011-08-16

The present invention relates to a system for inspection of stacked cargo containers. One embodiment of the invention generally comprises a plurality of stacked cargo containers arranged in rows or tiers, each container having a top, a bottom a first side, a second side, a front end, and a back end; a plurality of spacers arranged in rows or tiers; one or more mobile inspection devices for inspecting the cargo containers, wherein the one or more inspection devices are removeably disposed within the spacers, the inspection means configured to move through the spacers to detect radiation within the containers. The invented system can also be configured to inspect the cargo containers for a variety of other potentially hazardous materials including but not limited to explosive and chemical threats.

Industrial stacks design; Diseno de chimeneas industriales

Energy Technology Data Exchange (ETDEWEB)

Cacheux, Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1987-12-31

The Instituto de Investigaciones Electricas (IIE) though its Civil Works Department, develops, under contract with CFE`s Gerencia de Proyectos Termoelectricos (Management of Fossil Power Plant Projects), a series of methods for the design of stacks, which pretends to solve the a present day problem: the stack design of the fossil power plants that will go into operation during the next coming years in the country. [Espanol] El Instituto de Investigaciones Electricas (IIE), a traves del Departamento de Ingenieria Civil, desarrolla, bajo contrato con la Gerencia de Proyectos Termoelectricos, de la Comision Federal de Electricidad (CFE), un conjunto de metodos para el diseno de chimeneas, con el que se pretende resolver un problema inmediato: el diseno de las chimeneas de las centrales termoelectricas que entraran en operacion durante los proximos anos, en el pais.

Industrial stacks design; Diseno de chimeneas industriales

Energy Technology Data Exchange (ETDEWEB)

Cacheux, Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1986-12-31

The Instituto de Investigaciones Electricas (IIE) though its Civil Works Department, develops, under contract with CFE`s Gerencia de Proyectos Termoelectricos (Management of Fossil Power Plant Projects), a series of methods for the design of stacks, which pretends to solve the a present day problem: the stack design of the fossil power plants that will go into operation during the next coming years in the country. [Espanol] El Instituto de Investigaciones Electricas (IIE), a traves del Departamento de Ingenieria Civil, desarrolla, bajo contrato con la Gerencia de Proyectos Termoelectricos, de la Comision Federal de Electricidad (CFE), un conjunto de metodos para el diseno de chimeneas, con el que se pretende resolver un problema inmediato: el diseno de las chimeneas de las centrales termoelectricas que entraran en operacion durante los proximos anos, en el pais.

Computerized method and system for designing an aerodynamic focusing lens stack

Science.gov (United States)

Gard, Eric [San Francisco, CA; Riot, Vincent [Oakland, CA; Coffee, Keith [Diablo Grande, CA; Woods, Bruce [Livermore, CA; Tobias, Herbert [Kensington, CA; Birch, Jim [Albany, CA; Weisgraber, Todd [Brentwood, CA

2011-11-22

A computerized method and system for designing an aerodynamic focusing lens stack, using input from a designer related to, for example, particle size range to be considered, characteristics of the gas to be flowed through the system, the upstream temperature and pressure at the top of a first focusing lens, the flow rate through the aerodynamic focusing lens stack equivalent at atmosphere pressure; and a Stokes number range. Based on the design parameters, the method and system determines the total number of focusing lenses and their respective orifice diameters required to focus the particle size range to be considered, by first calculating for the orifice diameter of the first focusing lens in the Stokes formula, and then using that value to determine, in iterative fashion, intermediate flow values which are themselves used to determine the orifice diameters of each succeeding focusing lens in the stack design, with the results being output to a designer. In addition, the Reynolds numbers associated with each focusing lens as well as exit nozzle size may also be determined to enhance the stack design.

Stacking machine learning classifiers to identify Higgs bosons at the LHC

International Nuclear Information System (INIS)

Alves, A.

2017-01-01

Machine learning (ML) algorithms have been employed in the problem of classifying signal and background events with high accuracy in particle physics. In this paper, we compare the performance of a widespread ML technique, namely, stacked generalization , against the results of two state-of-art algorithms: (1) a deep neural network (DNN) in the task of discovering a new neutral Higgs boson and (2) a scalable machine learning system for tree boosting, in the Standard Model Higgs to tau leptons channel, both at the 8 TeV LHC. In a cut-and-count analysis, stacking three algorithms performed around 16% worse than DNN but demanding far less computation efforts, however, the same stacking outperforms boosted decision trees. Using the stacked classifiers in a multivariate statistical analysis (MVA), on the other hand, significantly enhances the statistical significance compared to cut-and-count in both Higgs processes, suggesting that combining an ensemble of simpler and faster ML algorithms with MVA tools is a better approach than building a complex state-of-art algorithm for cut-and-count.

Scalable microbial fuel cell (MFC) stack for continuous real wastewater treatment.

Science.gov (United States)

Zhuang, Li; Zheng, Yu; Zhou, Shungui; Yuan, Yong; Yuan, Haoran; Chen, Yong

2012-02-01

A tubular air-cathode microbial fuel cell (MFC) stack with high scalability and low material cost was constructed and the ability of simultaneous real wastewater treatment and bioelectricity generation was investigated under continuous flow mode. At the two organic loading rates (ORLs) tested (1.2 and 4.9kg COD/m(3)d), five non-Pt MFCs connected in series and parallel circuit modes treating swine wastewater can enable an increase of the voltage and the current. The parallel stack retained high power output and the series connection underwent energy loss due to the substrate cross-conduction effect. With continuous electricity production, the parallel stack achieved 83.8% of COD removal and 90.8% of NH(4)(+)-N removal at 1.2kg COD/m(3)d, and 77.1% COD removal and 80.7% NH(4)(+)-N removal at 4.9kg COD/m(3)d. The MFC stack system in this study was demonstrated to be able to treat real wastewater with the added benefit of harvesting electricity energy. Copyright © 2011 Elsevier Ltd. All rights reserved.

Stacking multiple connecting functional materials in tandem organic light-emitting diodes

Science.gov (United States)

Zhang, Tao; Wang, Deng-Ke; Jiang, Nan; Lu, Zheng-Hong

2017-02-01

Tandem device is an important architecture in fabricating high performance organic light-emitting diodes and organic photovoltaic cells. The key element in making a high performance tandem device is the connecting materials stack, which plays an important role in electric field distribution, charge generation and charge injection. For a tandem organic light-emitting diode (OLED) with a simple Liq/Al/MoO3 stack, we discovered that there is a significant current lateral spreading causing light emission over an extremely large area outside the OLED pixel when the Al thickness exceeds 2 nm. This spread light emission, caused by an inductive electric field over one of the device unit, limits one’s ability to fabricate high performance tandem devices. To resolve this issue, a new connecting materials stack with a C60 fullerene buffer layer is reported. This new structure permits optimization of the Al metal layer in the connecting stack and thus enables us to fabricate an efficient tandem OLED having a high 155.6 cd/A current efficiency and a low roll-off (or droop) in current efficiency.

Method for priming and DNA sequencing

Energy Technology Data Exchange (ETDEWEB)

Mugasimangalam, R.C.; Ulanovsky, L.E.

1997-12-01

A method is presented for improving the priming specificity of an oligonucleotide primer that is non-unique in a nucleic acid template which includes selecting a continuous stretch of several nucleotides in the template DNA where one of the four bases does not occur in the stretch. This also includes bringing the template DNA in contract with a non-unique primer partially or fully complimentary to the sequence immediately upstream of the selected sequence stretch. This results in polymerase-mediated differential extension of the primer in the presence of a subset of deoxyribonucleotide triphosphates that does not contain the base complementary to the base absent in the selected sequence stretch. These reactions occur at a temperature sufficiently low for allowing the extension of the non-unique primer. The method causes polymerase-mediated extension reactions in the presence of all four natural deoxyribonucleotide triphosphates or modifications. At this high temperature discrimination occurs against priming sites of the non-unique primer where the differential extension has not made the primer sufficiently stable to prime. However, the primer extended at the selected stretch is sufficiently stable to prime.

40 CFR 61.33 - Stack sampling.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.33 Section 61.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Unless a waiver of emission testing is obtained under § 61.13, each owner or operator...

The Role of Relative Sea Level Changes in Diagenetic Processes and Stacking Pattern of Kangan Formation Sediments in one of the Persian Gulf Fields

Directory of Open Access Journals (Sweden)

حسن اشراقی

2016-01-01

Full Text Available The Lower to Middle Triassic aged Kangan Formation is one of the most significant carbonate gas reservoirs in Iranian territory. In this study, thin sections data were used to recognize microfacies, sedimentary environments and the interaction between diagenetic processes and facies stacking pattern in a sequence stratigraphic framework. Petrographic studies leaded to recognition of eight microfacies related to three facies belts including tidal flat, lagoon and shoal. Moreover, the observed microfacies patterns indicate a ramp carbonate platform as depositional environment for this carbonate succession. The main diagenetic processes of Kangan Formation include micritization, isopachous and fibrous cements (primary marine diagenesis, dissolution and moldic porosity (meteoric diagenesis, compaction and stylolitization (secondary diagenesis. Based on facies changes, two third-order sequences were specified, each of which could be divided into two systems tracts including transgressive systems tract (TST and highstand systems tract (HST. In addition, sequence boundaries were identified with bedded, massive and nodular anhydrite. These facies, that are indicative of maximum sea level fall, were deposited in hypersaline lagoons. There is a close association between diagenetic processes and relative sea level changes of Kangan Formation, so that diagenetic processes of studied succession have been controlled by sediments stacking patterns during transgression and regression of sea level. During the transgression, the main diagenetic processes in shoal facies are marine cementation and dolomitization in lagoon and tidal flat facies. However, during the sea level fall, these processes include dissolution in shoal facies and dolomitization, anhydrite nodule formation and cementation in lagoon and tidal flat settings.

Prediction of residual stress distribution in multi-stacked thin film by curvature measurement and iterative FEA

International Nuclear Information System (INIS)

Choi, Hyeon Chang; Park, Jun Hyub

2005-01-01

In this study, residual stress distribution in multi-stacked film by MEMS (Micro-Electro Mechanical System) process is predicted using Finite Element Method (FEM). We develop a finite element program for REsidual Stress Analysis (RESA) in multi-stacked film. The RESA predicts the distribution of residual stress field in multi-stacked film. Curvatures of multi-stacked film and single layers which consist of the multi-stacked film are used as the input to the RESA. To measure those curvatures is easier than to measure a distribution of residual stress. To verify the RESA, mean stresses and stress gradients of single and multilayers are measured. The mean stresses are calculated from curvatures of deposited wafer by using Stoney's equation. The stress gradients are calculated from the vertical deflection at the end of cantilever beam. To measure the mean stress of each layer in multi-stacked film, we measure the curvature of wafer with the film after etching layer by layer in multi-stacked film

Dock 'n roll: folding of a silk-inspired polypeptide into an amyloid-like beta solenoid.

Science.gov (United States)

Zhao, Binwu; Cohen Stuart, Martien A; Hall, Carol K

2016-04-20

Polypeptides containing the motif ((GA)mGX)n occur in silk and have a strong tendency to self-assemble. For example, polypeptides containing (GAGAGAGX)n, where X = G or H have been observed to form filaments; similar sequences but with X = Q have been used in the design of coat proteins (capsids) for artificial viruses. The structure of the (GAGAGAGX)m filaments has been proposed to be a stack of peptides in a β roll structure with the hydrophobic side chains pointing outwards (hydrophobic shell). Another possible configuration, a β roll or β solenoid structure which has its hydrophobic side chains buried inside (hydrophobic core) was, however, overlooked. We perform ground state analysis as well as atomic-level molecular dynamics simulations, both on single molecules and on two-molecule stacks of the silk-inspired sequence (GAGAGAGQ)10, to decide whether the hydrophobic core or the hydrophobic shell configuration is the most stable one. We find that a stack of two hydrophobic core molecules is energetically more favorable than a stack of two hydrophobic shell molecules. A shell molecule initially placed in a perfect β roll structure tends to rotate its strands, breaking in-plane hydrogen bonds and forming out-of-plane hydrogen bonds, while a core molecule stays in the β roll structure. The hydrophobic shell structure has type II' β turns whereas the core configuration has type II β turns; only the latter secondary structure agrees well with solid-state NMR experiments on a similar sequence (GA)15. We also observe that the core stack has a higher number of intra-molecular hydrogen bonds and a higher number of hydrogen bonds between stack and water than the shell stack. Hence, we conclude that the hydrophobic core configuration is the most likely structure. In the stacked state, each peptide has more intra-molecular hydrogen bonds than a single folded molecule, which suggests that stacking provides the extra stability needed for molecules to reach the folded

Dock ’n Roll: Folding of a Silk-Inspired Polypeptide into an Amyloid-like Beta Solenoid

Science.gov (United States)

Zhao, Binwu; Cohen Stuart, Martien A.; Hall, Carol K.

2016-01-01

Polypeptides containing the motif ((GA)mGX)n occur in silk (we refer to them as ‘silk-like’) and have a strong tendency to self-assemble. For example, polypeptides containing (GAGAGAGX)n, where X = G or H have been observed to form filaments; similar sequences but with X = Q have been used in the design of coat proteins (capsids) for artificial viruses. The structure of the (GAGAGAGX)m filaments has been proposed to be a stack of peptides in a β roll structure with the hydrophobic side chains pointing outwards (hydrophobic shell). Another possible configuration, a β roll or β solenoid structure which has its hydrophobic side chains buried inside (hydrophobic core) was, however, overlooked. We perform ground state analysis as well as atomic-level molecular dynamics simulations, both on single molecules and on two-molecule stacks of the silk-inspired sequence (GAGAGAGQ)10, to decide whether the hydrophobic core or the hydrophobic shell configuration is the most stable one. We find that a stack of two hydrophobic core molecules is energetically more favorable than a stack of two shell molecules. A shell molecule initially placed in a perfect β roll structure tends to rotate its strands, breaking in-plane hydrogen bonds and forming out-of-plane hydrogen bonds, while a core molecule stays in the β roll structure. The hydrophobic shell structure has type II’ β turns whereas the core configuration has type II β turns; only the latter secondary structure agrees well with solid-state NMR experiments on a similar sequence (GA)15. We also observe that the core stack has a higher number of intra-molecular hydrogen bonds and a higher number of hydrogen bonds between stack and water than the shell stack. Hence, we conclude that the hydrophobic core configuration is the most likely structure. In the stacked state, each peptide has more intra-molecular hydrogen bonds than a single folded molecule, which suggests that stacking provides the extra stability needed for

Stack and area tritium monitoring systems for the tokamak fusion test reactor (TFTR)

International Nuclear Information System (INIS)

Pearson, G.G.; Meixler, L.D.; Sirsingh, R.A.P.

1992-01-01

This paper reports on the TFTR Tritium Stack and Area Monitoring Systems which have been developed to provide the required level of reliability in a cost effective manner consistent with the mission of the Tritium Handling System on TFTR. Personnel protection, environmental responsibility, and tritium containing system integrity have been the considerations in system design. During the Deuterium-Tritium (D-T) experiments on TFTR, tritium will be used for the first time as one of the fuels. Area monitors provide surveillance of the air in various rooms at TFTR. Stack monitors monitor the air at the TFTR test site that is exhausted through the HVAC systems, from the room exhaust stacks and the tritium systems process vents. The philosophies for the implementation of the Stack and Area Tritium Monitoring Systems at TFTR are to use hardwired controls wherever personnel protection is involved, and to take advantage of modern intelligent controllers to provide a distributed system to support the functions of tracking, displaying, and archiving concentration levels of tritium for all of the monitored areas and stacks

Effect of Additional Structure on Effective Stack Height of Gas Dispersion in Atmosphere

Directory of Open Access Journals (Sweden)

Takenobu Michioka

2016-03-01

Full Text Available Wind-tunnel experiments were conducted to evaluate the effect of additional structure (building, sea wall and banking on the effective stack height, which is usually used in safety analyses of nuclear power facilities in Japan. The effective stack heights were estimated with and without the additional structure in addition to the reactor building while varying several conditions such as the source height, the height of additional structure and the distance between the source position and the additional structure. When the source height is equivalent to the reactor building height, the additional structure enhances both the vertical and horizontal gas dispersion widths and decreases the ground gas concentration, and it means that the additional structure does not decrease the effective stack height. When the source height is larger than the reactor height, the additional structures might affect the effective stack height. As the distance between the source and the additional structure decreases, or as the height of the additional structure increases, the structure has a larger effect on the effective stack height.

Fabrication of a Cu/Ni stack in supercritical carbon dioxide at low-temperature

Energy Technology Data Exchange (ETDEWEB)

Rasadujjaman, Md, E-mail: rasadphy@duet.ac.bd [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511 (Japan); Department of Physics, Dhaka University of Engineering & Technology, Gazipur 1700 (Bangladesh); Watanabe, Mitsuhiro [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511 (Japan); Sudoh, Hiroshi; Machida, Hideaki [Gas-Phase Growth Ltd., 2-24-16 Naka, Koganei, Tokyo 184-0012 (Japan); Kondoh, Eiichi [Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu, Yamanashi 400-8511 (Japan)

2015-09-30

We report the low-temperature deposition of Cu on a Ni-lined substrate in supercritical carbon dioxide. A novel Cu(I) amidinate precursor was used to reduce the deposition temperature. From the temperature dependence of the growth rate, the activation energy for Cu growth on the Ni film was determined to be 0.19 eV. The films and interfaces were characterized by Auger electron spectroscopy. At low temperature (140 °C), we successfully deposited a Cu/Ni stack with a sharp Cu/Ni interface. The stack had a high adhesion strength (> 1000 mN) according to microscratch testing. The high adhesion strength originated from strong interfacial bonding between the Cu and the Ni. However, at a higher temperature (240 °C), significant interdiffusion was observed and the adhesion became weak. - Highlights: • Cu/Ni stack fabricated in supercritical CO{sub 2} at low temperature. • A novel Cu(I) amidinate precursor was used to reduce the deposition temperature. • Adhesion strength of Cu/Ni stack improved dramatically. • Fabricated Cu/Ni stack is suitable for Cu interconnections in microelectronics.

Optimal Stack Layout in a Sea Container Terminal with Automated Lifting Vehicles

NARCIS (Netherlands)

D. Roy (Debjit); A. Gupta (Akash); S. Parhi (Sampanna); M.B.M. de Koster (René)

2014-01-01

textabstractContainer terminal performance is largely determined by its design decisions, which include the number and type of quay cranes (QCs), stack cranes (SCs), transport vehicles, vehicle travel path, and stack layout. The terminal design process is complex because it is affected by factors

Tablet—next generation sequence assembly visualization

Science.gov (United States)

Milne, Iain; Bayer, Micha; Cardle, Linda; Shaw, Paul; Stephen, Gordon; Wright, Frank; Marshall, David

2010-01-01

Summary: Tablet is a lightweight, high-performance graphical viewer for next-generation sequence assemblies and alignments. Supporting a range of input assembly formats, Tablet provides high-quality visualizations showing data in packed or stacked views, allowing instant access and navigation to any region of interest, and whole contig overviews and data summaries. Tablet is both multi-core aware and memory efficient, allowing it to handle assemblies containing millions of reads, even on a 32-bit desktop machine. Availability: Tablet is freely available for Microsoft Windows, Apple Mac OS X, Linux and Solaris. Fully bundled installers can be downloaded from http://bioinf.scri.ac.uk/tablet in 32- and 64-bit versions. Contact: tablet@scri.ac.uk PMID:19965881

A cross-stacked plasmonic nanowire network for high-contrast femtosecond optical switching.

Science.gov (United States)

Lin, Yuanhai; Zhang, Xinping; Fang, Xiaohui; Liang, Shuyan

2016-01-21

We report an ultrafast optical switching device constructed by stacking two layers of gold nanowires into a perpendicularly crossed network, which works at a speed faster than 280 fs with an on/off modulation depth of about 22.4%. The two stacks play different roles in enhancing consistently the optical switching performance due to their different dependence on the polarization of optical electric fields. The cross-plasmon resonance based on the interaction between the perpendicularly stacked gold nanowires and its Fano-coupling with Rayleigh anomaly is the dominant mechanism for such a high-contrast optical switching device.

Research and Development of Fully Automatic Alien Smoke Stack and Packaging System

Science.gov (United States)

Yang, Xudong; Ge, Qingkuan; Peng, Tao; Zuo, Ping; Dong, Weifu

2017-12-01

The problem of low efficiency of manual sorting packaging for the current tobacco distribution center, which developed a set of safe efficient and automatic type of alien smoke stack and packaging system. The functions of fully automatic alien smoke stack and packaging system adopt PLC control technology, servo control technology, robot technology, image recognition technology and human-computer interaction technology. The characteristics, principles, control process and key technology of the system are discussed in detail. Through the installation and commissioning fully automatic alien smoke stack and packaging system has a good performance and has completed the requirements for shaped cigarette.

Complementary and bipolar regimes of resistive switching in TiN/HfO{sub 2}/TiN stacks grown by atomic-layer deposition

Energy Technology Data Exchange (ETDEWEB)

Egorov, K.V.; Kirtaev, R.V.; Markeev, A.M.; Zablotskiy, A.V. [Moscow Institute of Physics and Technology, Institutskii per. 9, 141700, Dolgoprudny (Russian Federation); Lebedinskii, Yu.Yu.; Matveyev, Yu.A.; Zenkevich, A.V. [Moscow Institute of Physics and Technology, Institutskii per. 9, 141700, Dolgoprudny (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoye shosse 31, 115409, Moscow (Russian Federation); Orlov, O.M. [Scientific Research Institute of Molecular Electronics and Plant ' ' Micron' ' , 124462, Zelenograd (Russian Federation)

2015-04-01

Atomic-layer deposition (ALD) technique in combination with in vacuo X-ray photoelectron spectroscopy (XPS) analysis has been successfully employed to obtain fully ALD-grown planar TiN/HfO{sub 2}/TiN metal-insulator-metal structures for resistive random access memory (ReRAM) memory elements. In vacuo XPS analysis of ALD-grown TiN/HfO{sub 2}/TiN stacks reveals the presence of the ultrathin oxidized layers consisting of TiON (∝0.5 nm) and TiO{sub 2} (∝0.6 nm) at the bottom TiN/HfO{sub 2} interface (i); the nonoxidized TiN at the top HfO{sub 2}/TiN interface (ii); the oxygen deficiency in the HfO{sub 2} layer does not exceed the XPS detection limit (iii). Electroformed ALD TiN/HfO{sub 2}/TiN stacks reveal both conventional bipolar and complementary types of resistive switching. In the complementary resistive switching regime, each programming sequence is terminated by a reset operation, leaving the TiN/HfO{sub 2}/TiN stack in a high-resistance state. The observed feature can avoid detrimental leaky paths during successive reading operation, which is useful in the passive ReRAM arrays without a selector element. The bipolar regime of resistive switching is found to reveal the gradual character of the SET and RESET switching processes. Long-term potentiation and depression tests performed on ALD-grown TiN/HfO{sub 2}/TiN stacks indicate that they can be used as electronic synapse devices for the implementation of emerging neuromorphic computation systems. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Design and experimental characterization of a 350 W High Temperature PEM fuel cell stack

Directory of Open Access Journals (Sweden)

Nicola Zuliani

2011-01-01

Full Text Available High Temperature Proton Exchange Membrane (HT PEM fuel cell based on polybenzimidazole (PBI polymer and phosphoric acid, can be operated at temperature between 120 °C and 180 °C. Reactants humidification is not required and CO content up to 2% in the fuel can be tolerated, affecting only marginally performance. This is what makes HT PEM very attractive, as low quality reformed hydrogen can be used and water management problems are avoided. Till nowadays, from experimental point of view, only few studies relate to the development and characterization of high temperature stacks. The aim of this work is to present the main design features and the performance curves of a 25 cells HT PEM stack based on PBI and phosphoric acid membranes. Performance curves refer to the stack operating with two type of fuels: pure hydrogen and a gas mixture simulating a typical steam reformer output. The stack voltage distribution analysis and the stack temperature distribution analysis suggest that cathode air could be used as coolant leading to a better thermal management. This could simplify stack design and system BOP, thus increasing system performance.

Development of HT-PEMFC components and stack for CHP unit

Energy Technology Data Exchange (ETDEWEB)

Jensen, Jens Oluf; Li, Q. (Technical Univ. of Denmark, Dept. of Chemistry, Kgs. Lyngby (Denmark)); Terkelsen, C.; Rudbech, H.C.; Steenberg, T. (Danish Power System Aps, Charlottenlund (Denmark)); Thibault de Rycke (IRD Fuel Cell A/S, Svendborg (Denmark))

2009-10-15

The aim of the project has been to further develop components for an all Danish high temperature PEM fuel cells stack for application in combined heat and power units (CHP units). The final product aimed at was a 1.5-2 kW stack for operation at 150-200 deg. C. The project follows the previous PSO project 4760, 'High Temperature PEM Fuel Cell'. The project has addressed the HT-PEM fuel cells form a components point of view and the materials here for. The main areas were polymer and membrane development, electrode and MEA development (MEA = membrane electrode assembly, i.e. the cells.) and stack development. The membrane development begins with the polymer. The polymerization technique was improved significantly in two ways. Better understanding of the process and the critical issues has led to more reproducible results with repeated high molecular weights. The molecular weight is decisive for the membrane strength and durability. The process was also scaled up to 100-200 g polymer pr. batch in a new polymerization facility build during the project. It is dimensioned for larger batches too, but this was not verified during the project. The polymer cannot be purchased in the right quality for fuel cell membranes and it is important that it manufacture is not a limiting factor at the present state. Experiments with other membrane casting techniques were also made. The traditional PBI doped with phosphoric acid is still the state of art membrane for the HT-PEM fuel cells, but progress was also made with modified membranes. Different variants of PBI were synthesized and tested. Electrodes have been manufactured by a spray technique in contrast to the previously applied tape casting. The hand held spray gun previously led to an improvement of the electrodes, but the reproducibility was limited. Subsequently the construction of a semi automated spray machine was started and results like of the best hand sprayed electrodes were obtained. A viable way of MEA rim

A polymer electrolyte fuel cell stack for stationary power generation from hydrogen fuel

Energy Technology Data Exchange (ETDEWEB)

Gottesfeld, S. [Los Alamos National Lab., NM (United States)

1995-09-01

The fuel cell is the most efficient device for the conversion of hydrogen fuel to electric power. As such, the fuel cell represents a key element in efforts to demonstrate and implement hydrogen fuel utilization for electric power generation. The low temperature, polymer electrolyte membrane fuel cell (PEMFC) has recently been identified as an attractive option for stationary power generation, based on the relatively simple and benign materials employed, the zero-emission character of the device, and the expected high power density, high reliability and low cost. However, a PEMFC stack fueled by hydrogen with the combined properties of low cost, high performance and high reliability has not yet been demonstrated. Demonstration of such a stack will remove a significant barrier to implementation of this advanced technology for electric power generation from hydrogen. Work done in the past at LANL on the development of components and materials, particularly on advanced membrane/electrode assemblies (MEAs), has contributed significantly to the capability to demonstrate in the foreseeable future a PEMFC stack with the combined characteristics described above. A joint effort between LANL and an industrial stack manufacturer will result in the demonstration of such a fuel cell stack for stationary power generation. The stack could operate on hydrogen fuel derived from either natural gas or from renewable sources. The technical plan includes collaboration with a stack manufacturer (CRADA). It stresses the special requirements from a PEMFC in stationary power generation, particularly maximization of the energy conversion efficiency, extension of useful life to the 10 hours time scale and tolerance to impurities from the reforming of natural gas.

Dynamic Model of the High Temperature Proton Exchange Membrane Fuel Cell Stack Temperature

DEFF Research Database (Denmark)

Andreasen, Søren Juhl; Kær, Søren Knudsen

2009-01-01

The present work involves the development of a model for predicting the dynamic temperature of a high temperature proton exchange membrane (HTPEM) fuel cell stack. The model is developed to test different thermal control strategies before implementing them in the actual system. The test system co...... elements for start-up, heat conduction through stack insulation, cathode air convection, and heating of the inlet gases in the manifold. Various measurements are presented to validate the model predictions of the stack temperatures....

Temperature and flow distribution in planar SOFC stacks

Directory of Open Access Journals (Sweden)

Monica Østenstad

1995-07-01

Full Text Available Simulation of a planar Solid Oxide Fuel Cell stack requires the solution of the mass balances of the chemical species, the energy balances, the charge balance and the channel flow equations in order to compute the species concentrations, the temperature distributions, the current density and the channel flows. The unit cell geometry can be taken into account by combining detailed modeling of a unit cell with a homogenized model of a whole stack. In this study the effect of the asymmetric temperature distribution on the channel flows in a conventional cross-flow design has been investigated. The bidirectional cross-flow design is introduced, for which we can show more directional temperature and flow distributions.

Stable MSAP markers for the distinction of Vitis vinifera cv Pinot noir clones.

Science.gov (United States)

Ocaña, Juan; Walter, Bernard; Schellenbaum, Paul

2013-11-01

Grapevine is one of the most economically important fruit crops. Molecular markers have been used to study grapevine diversity. For instance, simple sequence repeats are a powerful tool for identification of grapevine cultivars, while amplified fragment length polymorphisms have shown their usefulness in intra-varietal diversity studies. Other techniques such as sequence-specific amplified polymorphism are based on the presence of mobile elements in the genome, but their detection lies upon their activity. Relevant attention has been drawn toward epigenetic sources of variation. In this study, a set of Vitis vinifera cv Pinot noir clones were analyzed using the methylation-sensitive amplified polymorphism technique with isoschizomers MspI and HpaII. Nine out of fourteen selective primer combinations were informative and generated two types of polymorphic fragments which were categorized as "stable" and "unstable." In total, 23 stable fragments were detected and they discriminated 92.5 % of the studied clones. Detected stable polymorphisms were either common to several clones, restricted to a few clones or unique to a single clone. The identification of these stable epigenetic markers will be useful in clonal diversity studies. We highlight the relevance of stable epigenetic variation in V. vinifera clones and analyze at which level these markers could be applicable for the development of forthright techniques for clonal distinction.

296-B-10 stack monitoring and sampling system annual system assessment report

International Nuclear Information System (INIS)

Ridge, T.M.

1995-01-01

B Plant Administration Manual, requires an annual system assessment to evaluate and report the present condition of the sampling and monitoring system associated with stack 296-B-10 at B Plant. The ventilation system of WESF (Waste Encapsulation and Storage Facility) is designed to provide airflow patterns so that air movement throughout the building is from areas of lesser radioactivity to areas of greater radioactivity. All potentially contaminated areas are maintained at a negative pressure with respect to the atmosphere so that air flows into the building at all times. The exhaust discharging through the 296-B-10 stack is continuously monitored and sampled using a sampling and monitoring probe assembly located approximately 17.4 meters (57 feet) above the base of the stack. The probe assembly consists of 5 nozzles for the sampling probe and 2 nozzles to monitor the flow. The sampling and monitoring system associated with Stack 296-B-10 is functional and performing satisfactorily

Regular control of monitors for effluents from nuclear power plant stacks

International Nuclear Information System (INIS)

Stroem, L.

1979-01-01

The report describes a test procedure for emission monitoring devices for nuclear power plants. The follosing procedures are described, inspection, determination of the air flow through the stack, measurement and adjustment of the flow in the stack loop, measurement and adjustment of flow and density in the measuring loop, calibration of the gas detector, efficiency of sampling of methyliodide and aerosol. (K.K.)

Model and Design of a Power Driver for Piezoelectric Stack Actuators

Directory of Open Access Journals (Sweden)

Chiaberge M

2010-01-01

Full Text Available A power driver has been developed to control piezoelectric stack actuators used in automotive application. An FEM model of the actuator has been implemented starting from experimental characterization of the stack and mechanical and piezoelectric parameters. Experimental results are reported to show a correct piezoelectric actuator driving method and the possibility to obtain a sensorless positioning control.

Confirmation of vanadium complex formation using electrospray mass spectrometry and determination of vanadium speciation by sample stacking capillary electrophoresis

International Nuclear Information System (INIS)

Chen Zuliang; Owens, Gary; Naidu, Ravendra

2007-01-01

Capillary zone electrophoresis (CZE) with UV detection was used to determine vanadium species. Nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol-bis(2-aminoethylether)-tetraacetic acid (EGTA) and 2,6-pyridinedicarboxylic acid (PDCA) were investigated to determine whether these ligands formed stable anionic complexes with vanadium. Of all the ligands studied HEDTA was the most suitable ligand because it gave the largest UV response with reasonable migration time. Electrospray mass spectrometry (ES-MS) was used to confirm the formation of [VO 2 (HEDTA)] 2- and [VO(HEDTA)] 1- in solution. An electrolyte containing 25 mM phosphate, 0.25 mM tetradecyltrimethylammonium bromide (TTAB) at pH 5.5 was optimum for the separation of these anionic vanadium complexes. Sample stacking techniques, including large-volume sample stacking (LVSS) and field-amplified sample injection (FASI), were tested to improve the sensitivity. Best sensitivity was obtained using FASI, with detection limits of 0.001 μM, equivalent to 0.4 μg L -1 , for [VO 2 (HEDTA)] 2- and 0.01 μM, equivalent to 3.4 μg L -1 for [VO(HEDTA)] 1- . The utility of the method for the speciation of V(IV) and V(V) was demonstrated using ground water samples

High Yield Chemical Vapor Deposition Growth of High Quality Large-Area AB Stacked Bilayer Graphene

Science.gov (United States)

Liu, Lixin; Zhou, Hailong; Cheng, Rui; Yu, Woo Jong; Liu, Yuan; Chen, Yu; Shaw, Jonathan; Zhong, Xing; Huang, Yu; Duan, Xiangfeng

2012-01-01

Bernal stacked (AB stacked) bilayer graphene is of significant interest for functional electronic and photonic devices due to the feasibility to continuously tune its band gap with a vertical electrical field. Mechanical exfoliation can be used to produce AB stacked bilayer graphene flakes but typically with the sizes limited to a few micrometers. Chemical vapor deposition (CVD) has been recently explored for the synthesis of bilayer graphene but usually with limited coverage and a mixture of AB and randomly stacked structures. Herein we report a rational approach to produce large-area high quality AB stacked bilayer graphene. We show that the self-limiting effect of graphene growth on Cu foil can be broken by using a high H2/CH4 ratio in a low pressure CVD process to enable the continued growth of bilayer graphene. A high temperature and low pressure nucleation step is found to be critical for the formation of bilayer graphene nuclei with high AB stacking ratio. A rational design of a two-step CVD process is developed for the growth of bilayer graphene with high AB stacking ratio (up to 90 %) and high coverage (up to 99 %). The electrical transport studies demonstrated that devices made of the as-grown bilayer graphene exhibit typical characteristics of AB stacked bilayer graphene with the highest carrier mobility exceeding 4,000 cm2/V·s at room temperature, comparable to that of the exfoliated bilayer graphene. PMID:22906199

Salt Concentration Differences Alter Membrane Resistance in Reverse Electrodialysis Stacks

KAUST Repository

Geise, Geoffrey M.

2014-01-14

Membrane ionic resistance is usually measured by immersing the membrane in a salt solution at a single, fixed concentration. While salt concentration is known to affect membrane resistance when the same concentration is used on both sides of the membrane, little is known about membrane resistance when the membrane is placed between solutions of different concentrations, such as in a reverse electrodialysis (RED) stack. Ionic resistance measurements obtained using Selemion CMV and AMV that separated sodium chloride and ammonium bicarbonate solutions of different concentrations were greater than those measured using only the high-concentration solution. Measured RED stack resistances showed good agreement with resistances calculated using an equivalent series resistance model, where the membranes accounted for 46% of the total stack resistance. The high area resistance of the membranes separating different salt concentration solutions has implications for modeling and optimizing membranes used in RED systems.

MEAN STACK WEB DEVELOPMENT

OpenAIRE

Le Thanh, Nghi

2017-01-01

The aim of the thesis is to provide a universal website using JavaScript as the main programming language. It also shows the basic parts anyone need to create a web application. The thesis creates a simple CMS using MEAN stack. MEAN is a collection of JavaScript based technologies used to develop web application. It is an acronym for MongoDB, Express, AngularJS and Node.js. It also allows non-technical users to easily update and manage a website’s content. But the application also lets o...

Instant BlueStacks

CERN Document Server

Judge, Gary

2013-01-01

Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A fast-paced, example-based approach guide for learning BlueStacks.This book is for anyone with a Mac or PC who wants to run Android apps on their computer. Whether you want to play games that are freely available for Android but not your computer, or you want to try apps before you install them on a physical device or use it as a development tool, this book will show you how. No previous experience is needed as this is written in plain English

Variation of long-period stacking order structures in rapidly solidified Mg97Zn1Y2 alloy

International Nuclear Information System (INIS)

Matsuda, M.; Ii, S.; Kawamura, Y.; Ikuhara, Y.; Nishida, M.

2005-01-01

The long-period stacking order (LPSO) structures in rapidly solidified Mg 97 Zn 1 Y 2 alloy have been studied by conventional and high-resolution transmission electron microscopes (HRTEMs). There are four kinds of stacking sequences in the LPSO structures, i.e., 18R of ABABABCACACABCBCBC, 14H of ACBCBABABABCBC, 10H of ABACBCBCAB and 24R of ABABABABCACACACABCBCBCBC. The 18R structure is dominantly observed in the present study. The rest three are occasionally observed in places. The 10H and 24R structures are recently discovered. The lattice constants of 18R(1-bar 1-bar -bar 1-bar 1-bar -bar 2) 3 , 14H(2-bar -bar 1-bar 2-bar -bar 1-bar 1-bar -bar 1-bar 1-bar -bar 2-bar 1-bar -bar 2), 10H(1-bar 3-bar -bar 1-bar 1-bar -bar 3-bar 1-bar ) and 24R(1-bar 1-bar -bar 1-bar 1-bar -bar 1-bar 1-bar -bar 2) 3 structures are estimated to be a=0.320nm and c=4.678nm, a=0.325nm and c=3.694nm, a=0.325nm and c=2.603nm, a=0.322nm and c=6.181nm for the hexagonal structure, respectively

Optical transceiver ICs based on 3D die-stacking of opto-electronic devices

NARCIS (Netherlands)

Duan, P.; Raz, O.; Smalbrugge, B.E.; Plassche, van de K.L.; Dorren, H.J.S.

2013-01-01

Wafer scale fabrication of the 3D stacked transceivers is discussed. Uniform open eye patterns at 10 Gb/s/channel of both 3D stacked transmitter and receiver ICs indicates that the interconnection technology is robust.

Calculating transport AC losses in stacks of high temperature superconductor coated conductors with magnetic substrates using FEM

International Nuclear Information System (INIS)

Ainslie, Mark D.; Flack, Tim J.; Campbell, Archie M.

2012-01-01

Properties of stacks of HTS coated conductors with and without a magnetic substrate. Non-magnetic substrate model is consistent with existing methods. Presence of a magnetic substrate increases the total AC loss of the stack. Differences and similarities between certain tapes within stacks are explained. Ferromagnetic loss of substrate negligible in most cases except small currents/fields. In this paper, the authors investigate the electromagnetic properties of stacks of high temperature superconductor (HTS) coated conductors with a particular focus on calculating the total transport AC loss. The cross-section of superconducting cables and coils is often modeled as a two-dimensional stack of coated conductors, and these stacks can be used to estimate the AC loss of a practical device. This paper uses a symmetric two dimensional (2D) finite element model based on the H formulation, and a detailed investigation into the effects of a magnetic substrate on the transport AC loss of a stack is presented. The number of coated conductors in each stack is varied from 1 to 150, and three types of substrate are compared: non-magnetic weakly magnetic and strongly magnetic. The non-magnetic substrate model is comparable with results from existing models for the limiting cases of a single tape (Norris) and an infinite stack (Clem). The presence of a magnetic substrate increases the total AC loss of the stack, due to an increased localized magnetic flux density, and the stronger the magnetic material, the further the flux penetrates into the stack overall. The AC loss is calculated for certain tapes within the stack, and the differences and similarities between the losses throughout the stack are explained using the magnetic flux penetration and current density distributions in those tapes. The ferromagnetic loss of the substrate itself is found to be negligible in most cases, except for small magnitudes of current. Applying these findings to practical applications, where AC

Stable plastid transformation in Scoparia dulcis L.

Science.gov (United States)

Muralikrishna, Narra; Srinivas, Kota; Kumar, Kalva Bharath; Sadanandam, Abbagani

2016-10-01

In the present investigation we report stable plastid transformation in Scoparia dulcis L., a versatile medicinal herb via particle gun method. The vector KNTc, harbouring aadA as a selectable marker and egfp as a reporter gene which were under the control of synthetic promoter pNG1014a, targets inverted repeats, trnR / t rnN of the plastid genome. By use of this heterologous vector, recovery of transplastomic lines with suitable selection protocol have been successfully established with overall efficiency of two transgenic lines for 25 bombarded leaf explants. PCR and Southern blot analysis demonstrated stable integration of foreign gene into the target sequences. The results represent a significant advancement of the plastid transformation technology in medicinal plants, which relevantly implements a change over in enhancing and regulating of certain metabolic pathways.

Low-power DRAM-compatible Replacement Gate High-k/Metal Gate Stacks

Science.gov (United States)

Ritzenthaler, R.; Schram, T.; Bury, E.; Spessot, A.; Caillat, C.; Srividya, V.; Sebaai, F.; Mitard, J.; Ragnarsson, L.-Å.; Groeseneken, G.; Horiguchi, N.; Fazan, P.; Thean, A.

2013-06-01

In this work, the possibility of integration of High-k/Metal Gate (HKMG), Replacement Metal Gate (RMG) gate stacks for low power DRAM compatible transistors is studied. First, it is shown that RMG gate stacks used for Logic applications need to be seriously reconsidered, because of the additional anneal(s) needed in a DRAM process. New solutions are therefore developed. A PMOS stack HfO2/TiN with TiN deposited in three times combined with Work Function metal oxidations is demonstrated, featuring a very good Work Function of 4.95 eV. On the other hand, the NMOS side is shown to be a thornier problem to solve: a new solution based on the use of oxidized Ta as a diffusion barrier is proposed, and a HfO2/TiN/TaOX/TiAl/TiN/TiN gate stack featuring an aggressive Work Function of 4.35 eV (allowing a Work Function separation of 600 mV between NMOS and PMOS) is demonstrated. This work paves the way toward the integration of gate-last options for DRAM periphery transistors.

A Simple Semantics and Static Analysis for Stack Inspection

Directory of Open Access Journals (Sweden)

Anindya Banerjee

2013-09-01

Full Text Available The Java virtual machine and the .NET common language runtime feature an access control mechanism specified operationally in terms of run-time stack inspection. We give a denotational semantics in "eager" form, and show that it is equivalent to the "lazy" semantics using stack inspection. We give a static analysis of safety, i.e., the absence of security errors, that is simpler than previous proposals. We identify several program transformations that can be used to remove run-time checks. We give complete, detailed proofs for safety of the analysis and for the transformations, exploiting compositionality of the eager semantics.

Interrelation of Entropic Contributors to π -Stacking in Solution

Science.gov (United States)

Starodub, Maria A.; Lantushenko, Anastasia O.; Evstigneev, Vladislav P.; Golovchenko, Igor V.; Mykhina, Yulia V.; Savin, Valery V.; Evstigneev, Maxim P.

2016-08-01

The recently published most complete set of thermodynamical data on self- and hetero-complexation of aromatic molecules measured under comparable experimental conditions were analyzed. The main aim of this study is to get insights into contribution of various entropic factors to π -stacking in aqueous solution. It was found that the experimental entropy change on π -stacking is determined by counterbalancing effects of two principal factors, i.e., the hydrophobic interaction (positive contribution) and the loss of degrees of freedom (negative contribution) modulated by the electrostatic contribution. Other factors, including the mixing entropy contribution, were shown to be less important.

Vertically stacked nanocellulose tactile sensor.

Science.gov (United States)

Jung, Minhyun; Kim, Kyungkwan; Kim, Bumjin; Lee, Kwang-Jae; Kang, Jae-Wook; Jeon, Sanghun

2017-11-16

Paper-based electronic devices are attracting considerable attention, because the paper platform has unique attributes such as flexibility and eco-friendliness. Here we report on what is claimed to be the firstly fully integrated vertically-stacked nanocellulose-based tactile sensor, which is capable of simultaneously sensing temperature and pressure. The pressure and temperature sensors are operated using different principles and are stacked vertically, thereby minimizing the interference effect. For the pressure sensor, which utilizes the piezoresistance principle under pressure, the conducting electrode was inkjet printed on the TEMPO-oxidized-nanocellulose patterned with micro-sized pyramids, and the counter electrode was placed on the nanocellulose film. The pressure sensor has a high sensitivity over a wide range (500 Pa-3 kPa) and a high durability of 10 4 loading/unloading cycles. The temperature sensor combines various materials such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), silver nanoparticles (AgNPs) and carbon nanotubes (CNTs) to form a thermocouple on the upper nanocellulose layer. The thermoelectric-based temperature sensors generate a thermoelectric voltage output of 1.7 mV for a temperature difference of 125 K. Our 5 × 5 tactile sensor arrays show a fast response, negligible interference, and durable sensing performance.

Generalized stacking fault energies of alloys.

Science.gov (United States)

Li, Wei; Lu, Song; Hu, Qing-Miao; Kwon, Se Kyun; Johansson, Börje; Vitos, Levente

2014-07-02

The generalized stacking fault energy (γ surface) provides fundamental physics for understanding the plastic deformation mechanisms. Using the ab initio exact muffin-tin orbitals method in combination with the coherent potential approximation, we calculate the γ surface for the disordered Cu-Al, Cu-Zn, Cu-Ga, Cu-Ni, Pd-Ag and Pd-Au alloys. Studying the effect of segregation of the solute to the stacking fault planes shows that only the local chemical composition affects the γ surface. The calculated alloying trends are discussed using the electronic band structure of the base and distorted alloys.Based on our γ surface results, we demonstrate that the previous revealed 'universal scaling law' between the intrinsic energy barriers (IEBs) is well obeyed in random solid solutions. This greatly simplifies the calculations of the twinning measure parameters or the critical twinning stress. Adopting two twinnability measure parameters derived from the IEBs, we find that in binary Cu alloys, Al, Zn and Ga increase the twinnability, while Ni decreases it. Aluminum and gallium yield similar effects on the twinnability.

Development and characterization of a three-dimensional radiochromic film stack dosimeter for megavoltage photon beam dosimetry.

Science.gov (United States)

McCaw, Travis J; Micka, John A; DeWerd, Larry A

2014-05-01

Three-dimensional (3D) dosimeters are particularly useful for verifying the commissioning of treatment planning and delivery systems, especially with the ever-increasing implementation of complex and conformal radiotherapy techniques such as volumetric modulated arc therapy. However, currently available 3D dosimeters require extensive experience to prepare and analyze, and are subject to large measurement uncertainties. This work aims to provide a more readily implementable 3D dosimeter with the development and characterization of a radiochromic film stack dosimeter for megavoltage photon beam dosimetry. A film stack dosimeter was developed using Gafchromic(®) EBT2 films. The dosimeter consists of 22 films separated by 1 mm-thick spacers. A Virtual Water™ phantom was created that maintains the radial film alignment within a maximum uncertainty of 0.3 mm. The film stack dosimeter was characterized using simulations and measurements of 6 MV fields. The absorbed-dose energy dependence and orientation dependence of the film stack dosimeter were investigated using Monte Carlo simulations. The water equivalence of the dosimeter was determined by comparing percentage-depth-dose (PDD) profiles measured with the film stack dosimeter and simulated using Monte Carlo methods. Film stack dosimeter measurements were verified with thermoluminescent dosimeter (TLD) microcube measurements. The film stack dosimeter was also used to verify the delivery of an intensity-modulated radiation therapy (IMRT) procedure. The absorbed-dose energy response of EBT2 film differs less than 1.5% between the calibration and film stack dosimeter geometries for a 6 MV spectrum. Over a series of beam angles ranging from normal incidence to parallel incidence, the overall variation in the response of the film stack dosimeter is within a range of 2.5%. Relative to the response to a normally incident beam, the film stack dosimeter exhibits a 1% under-response when the beam axis is parallel to the film

AIC-based diffraction stacking for local earthquake locations at the Sumatran Fault (Indonesia)

Science.gov (United States)

Hendriyana, Andri; Bauer, Klaus; Muksin, Umar; Weber, Michael

2018-05-01

We present a new workflow for the localization of seismic events which is based on a diffraction stacking approach. In order to address the effects from complex source radiation patterns, we suggest to compute diffraction stacking from a characteristic function (CF) instead of stacking the original waveform data. A new CF, which is called in the following mAIC (modified from Akaike Information Criterion) is proposed. We demonstrate that both P- and S-wave onsets can be detected accurately. To avoid cross-talk between P and S waves due to inaccurate velocity models, we separate the P and S waves from the mAIC function by making use of polarization attributes. Then, the final image function is represented by the largest eigenvalue as a result of the covariance analysis between P- and S-image functions. Results from synthetic experiments show that the proposed diffraction stacking provides reliable results. The workflow of the diffraction stacking method was finally applied to local earthquake data from Sumatra, Indonesia. Recordings from a temporary network of 42 stations deployed for nine months around the Tarutung pull-apart basin were analysed. The seismic event locations resulting from the diffraction stacking method align along a segment of the Sumatran Fault. A more complex distribution of seismicity is imaged within and around the Tarutung basin. Two lineaments striking N-S were found in the centre of the Tarutung basin which support independent results from structural geology.

Spatial walk-off compensated beta-barium borate stack for efficient deep-UV generation

Science.gov (United States)

Li, Da; Lee, Huai-Chuan; Meissner, Stephanie K.; Meissner, Helmuth E.

2018-02-01

Beta-Barium Borate (β-BBO) crystal is commonly used in nonlinear frequency conversion from visible to deep ultraviolet (DUV). However, in a single crystal BBO, its large spatial walk-off effect will reduce spatial overlap of ordinary and extraordinary beam, and thus degrade the conversion efficiency. To overcome the restrictions in current DUV conversion systems, Onyx applies adhesive-free bonding technique to replace the single crystal BBO with a spatial Walk-off Compensated (WOC) BBO stack, which is capable of correcting the spatial walk-off while retaining a constant nonlinear coefficient in the adjacent bonding layers. As a result, the β-BBO stack will provide good beam quality, high conversion efficiency, and broader acceptance angle and spectral linewidth, when compared with a single crystal of BBO. In this work, we report on performance of a spatial walk-off compensated β-BBO stack with adhesive-free bonding technique, for efficiently converting from the visible to DUV range. The physics behind the WOC BBO stack are demonstrated, followed by simulation of DUV conversion efficiency in an external resonance cavity. We also demonstrate experimentally the beam quality improvement in a 4-layer WOC BBO stack over a single BBO crystal.

On the relationship between the irregular reflector and the data processing by stacking; Hanshamen keijo to jugo shori ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Matsushima, J; Yokota, T; Miyazaki, T [Geological Survey of Japan, Tsukuba (Japan); Rokukawa, S [The University of Tokyo, Tokyo (Japan). Faculty of Engineering

1996-05-01

An examination was made on the possibility of data processing by stacking with scattered waves assumed in a seismic exploration analysis (diffraction stacking method). In the examination, a CDP stacking method and the diffraction stacking method were compared through numerical experiments in the case of imaging a flat reflection surface and an irregular reflection surface. As a result, it was revealed that the CDP stacking method for stacking mirror reflection waves was merely a processing to raise S/N ratio while the diffraction stacking method for stacking with scattered waves assumed contained a migrational aspect as well as an aspect to raise S/N ratio. Consequently, it was shown that, if an oscillator was properly arranged, a structural imaging was possible not by the shape of a reflection surface but by the diffraction stacking method. Additionally, the diffraction stacking method revealed that the imaging effect varied by frequency with the stacking effect decreased at high frequencies, and that no stacking effect decreased at low frequencies but resolution lowered in horizontal direction. 4 refs., 8 figs.

Minimizing End-to-End Interference in I/O Stacks Spanning Shared Multi-Level Buffer Caches

Science.gov (United States)

Patrick, Christina M.

2011-01-01

This thesis presents an end-to-end interference minimizing uniquely designed high performance I/O stack that spans multi-level shared buffer cache hierarchies accessing shared I/O servers to deliver a seamless high performance I/O stack. In this thesis, I show that I can build a superior I/O stack which minimizes the inter-application interference…

Nb/NiCu bilayers in single and stacked superconductive tunnel junctions: preliminary results

International Nuclear Information System (INIS)

Pepe, G.P.; Ruotolo, A.; Parlato, L.; Peluso, G.; Ausanio, G.; Carapella, G.; Latempa, R.

2004-01-01

We present preliminary experimental results concerning both single and stacked tunnel junctions in which one of the electrodes was formed by a superconductor/ferromagnet (S/F) bi-layer. In particular, in the stacked configuration a Nb/NiCu bi-layer was used as the intermediate electrode, and it was probed by tunneling on both sides. Tunnel junctions have been characterized in terms of current-voltage characteristics (IVC), and differential conductance. Preliminary steady-state injection-detection measurements performed in the stacked devices at T=4.2 K are also presented and discussed

Microsatellites grant more stable flanking genes

Directory of Open Access Journals (Sweden)

Joukhadar Reem

2012-10-01

Full Text Available Abstract Background Microsatellites, or simple sequence repeats (SSRs, are DNA sequences that include tandem copies of specific sequences no longer than six bases. SSRs are ubiquitous in all genomes and highly mutable. Presentation of the hypothesis Results from previous studies suggest that flanking regions of SSR are exhibit high stability in a wide range of organisms. We hypothesized that the SSRs ability to discard weak DNA polymerases could be responsible for this unusual stability. . When the weak polymerases are being decayed over SSRs, the flanking sequences would have higher opportunity to be replicated by more stable DNA polymerases. We present evidence of the molecular basis of our hypothesis. Testing the hypothesis The hypothesis could be tested by examining the activity of DNA polymerase during and after a number of PCRs. The PCR reactions should be run with the same SSR locus possessing differences in the SSR length. The hypothesis could also be tested by comparing the mutational rate of a transferred gene between two transformations. The first one has a naked T-DNA (transferred DNA, while the second one has the same T-DNA flanked with two SSRs. Implications of the hypothesis In any transformation experiment, flanking the T-DNA fragment with SSR sequences would result in more stably transferred genes. This process would decrease the unpredictable risks that may occur because of the mutational pressure on this foreign segment.

A Stack Cache for Real-Time Systems

DEFF Research Database (Denmark)

Schoeberl, Martin; Nielsen, Carsten

2016-01-01

Real-time systems need time-predictable computing platforms to allowfor static analysis of the worst-case execution time. Caches are important for good performance, but data caches arehard to analyze for the worst-case execution time. Stack allocated data has different properties related...

Scaling the CERN OpenStack cloud

Science.gov (United States)

Bell, T.; Bompastor, B.; Bukowiec, S.; Castro Leon, J.; Denis, M. K.; van Eldik, J.; Fermin Lobo, M.; Fernandez Alvarez, L.; Fernandez Rodriguez, D.; Marino, A.; Moreira, B.; Noel, B.; Oulevey, T.; Takase, W.; Wiebalck, A.; Zilli, S.

2015-12-01

CERN has been running a production OpenStack cloud since July 2013 to support physics computing and infrastructure services for the site. In the past year, CERN Cloud Infrastructure has seen a constant increase in nodes, virtual machines, users and projects. This paper will present what has been done in order to make the CERN cloud infrastructure scale out.

High-frequency self-aligned graphene transistors with transferred gate stacks

Science.gov (United States)

Cheng, Rui; Bai, Jingwei; Liao, Lei; Zhou, Hailong; Chen, Yu; Liu, Lixin; Lin, Yung-Chen; Jiang, Shan; Huang, Yu; Duan, Xiangfeng

2012-01-01

Graphene has attracted enormous attention for radio-frequency transistor applications because of its exceptional high carrier mobility, high carrier saturation velocity, and large critical current density. Herein we report a new approach for the scalable fabrication of high-performance graphene transistors with transferred gate stacks. Specifically, arrays of gate stacks are first patterned on a sacrificial substrate, and then transferred onto arbitrary substrates with graphene on top. A self-aligned process, enabled by the unique structure of the transferred gate stacks, is then used to position precisely the source and drain electrodes with minimized access resistance or parasitic capacitance. This process has therefore enabled scalable fabrication of self-aligned graphene transistors with unprecedented performance including a record-high cutoff frequency up to 427 GHz. Our study defines a unique pathway to large-scale fabrication of high-performance graphene transistors, and holds significant potential for future application of graphene-based devices in ultra–high-frequency circuits. PMID:22753503

Flow-induced plastic collapse of stacked fuel plates

Energy Technology Data Exchange (ETDEWEB)

Davis, D C; Scarton, H A

1985-03-01

Flow-induced plastic collapse of stacked fuel plate assemblies was first noted in experimental reactors such as the ORNL High Flux Reactor Assembly and the Engineering Test Reactor (ETR). The ETR assembly is a stack of 19 thin flat rectangular fuel plates separated by narrow channels through which a coolant flows to remove the heat generated by fission of the fuel within the plates. The uranium alloyed plates have been noted to buckle laterally and plastically collapse at the system design coolant flow rate of 10.7 m/s, thus restricting the coolant flow through adjacent channels. A methodology and criterion are developed for predicting the plastic collapse of ETR fuel plates. The criterion is compared to some experimental results and the Miller critical velocity theory.

Spam comments prediction using stacking with ensemble learning

Science.gov (United States)

Mehmood, Arif; On, Byung-Won; Lee, Ingyu; Ashraf, Imran; Choi, Gyu Sang

2018-01-01

Illusive comments of product or services are misleading for people in decision making. The current methodologies to predict deceptive comments are concerned for feature designing with single training model. Indigenous features have ability to show some linguistic phenomena but are hard to reveal the latent semantic meaning of the comments. We propose a prediction model on general features of documents using stacking with ensemble learning. Term Frequency/Inverse Document Frequency (TF/IDF) features are inputs to stacking of Random Forest and Gradient Boosted Trees and the outputs of the base learners are encapsulated with decision tree to make final training of the model. The results exhibits that our approach gives the accuracy of 92.19% which outperform the state-of-the-art method.

Development of internal manifold heat exchanger (IMHEX reg sign ) molten carbonate fuel cell stacks

Energy Technology Data Exchange (ETDEWEB)

Marianowski, L.G.; Ong, E.T.; Petri, R.J.; Remick, R.J.

1991-01-01

The Institute of Gas Technology (IGT) has been in the forefront of molten carbonate fuel cell (MCFC) development for over 25 years. Numerous cell designs have been tested and extensive tests have been performed on a variety of gas manifolding alternatives for cells and stacks. Based upon the results of these performance tests, IGT's development efforts started focusing on an internal gas manifolding concept. This work, initiated in 1988, is known today as the IMHEX{reg sign} concept. MCP has developed a comprehensive commercialization program loading to the sale of commercial units in 1996. MCP's role is in the manufacture of stack components, stack assembly, MCFC subsystem testing, and the design, marketing and construction of MCFC power plants. Numerous subscale (1 ft{sup 2}) stacks have been operated containing between 3 and 70 cells. These tests verified and demonstrated the viability of internal manifolding from technical (no carbonate pumping), engineering (relaxed part dimensional tolerance requirements), and operational (good gas sealing) aspects. Simplified fabrication, ease of assembly, the elimination of external manifolds and all associated clamping requirements has significantly lowered anticipated stack costs. Ongoing 1 ft{sup 2} stack testing is generating performance and endurance characteristics as a function of system specified operating conditions. Commercial-sized, full-area stacks (10 ft{sup 2}) are in the process of being assembled and will be tested in November. This paper will review the recent developments the MCFC scale-up and manufacture work of MCP, and the research and development efforts of IGT which support those efforts. 17 figs.

Development of internal manifold heat exchanger (IMHEX reg-sign) molten carbonate fuel cell stacks

International Nuclear Information System (INIS)

Marianowski, L.G.; Ong, E.T.; Petri, R.J.; Remick, R.J.

1991-01-01

The Institute of Gas Technology (IGT) has been in the forefront of molten carbonate fuel cell (MCFC) development for over 25 years. Numerous cell designs have been tested and extensive tests have been performed on a variety of gas manifolding alternatives for cells and stacks. Based upon the results of these performance tests, IGT's development efforts started focusing on an internal gas manifolding concept. This work, initiated in 1988, is known today as the IMHEX reg-sign concept. MCP has developed a comprehensive commercialization program loading to the sale of commercial units in 1996. MCP's role is in the manufacture of stack components, stack assembly, MCFC subsystem testing, and the design, marketing and construction of MCFC power plants. Numerous subscale (1 ft 2 ) stacks have been operated containing between 3 and 70 cells. These tests verified and demonstrated the viability of internal manifolding from technical (no carbonate pumping), engineering (relaxed part dimensional tolerance requirements), and operational (good gas sealing) aspects. Simplified fabrication, ease of assembly, the elimination of external manifolds and all associated clamping requirements has significantly lowered anticipated stack costs. Ongoing 1 ft 2 stack testing is generating performance and endurance characteristics as a function of system specified operating conditions. Commercial-sized, full-area stacks (10 ft 2 ) are in the process of being assembled and will be tested in November. This paper will review the recent developments the MCFC scale-up and manufacture work of MCP, and the research and development efforts of IGT which support those efforts. 17 figs

Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction System

Science.gov (United States)

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.

The double travelling salesman problem with multiple stacks - Formulation and heuristic solution approaches

DEFF Research Database (Denmark)

Petersen, Hanne Løhmann; Madsen, Oli B.G.

2009-01-01

This paper introduces the double travelling salesman problem with multiple stacks and presents four different metaheuristic approaches to its solution. The double TSP with multiple stacks is concerned with determining the shortest route performing pickups and deliveries in two separated networks...

Pre-stack estimation of time-lapse seismic velocity changes : an example from the Sleipner CO2-sequestration project

International Nuclear Information System (INIS)

Ghaderi, A.; Landro, M.; Ghaderi, A.

2005-01-01

Carbon dioxide (CO 2 ) is being injected into a shallow sand formation at around a 1,000 metre depth at the Sleipner Field located in the North Sea. It is expected that the CO 2 injected in the bottom of the formation, will form a plume consisting of CO 2 accumulating in thin lenses during migration up through the reservoir. Several studies have been published using stacked seismic data from 1994, 1999, 2001 and 2002. A thorough analysis of post-stack seismic data from the Sleipner CO2-Sequestration Pilot Project was conducted. Interpretation of seismic data is usually done on post-stack data. For a given subsurface reflection point, seismic data are acquired for various incidence angles, typically 40 angles. These 40 seismic signals are stacked together in order to reduce noise. The term pre-stack refers to seismic data prior to this step. For hydrocarbon-related 4-dimensional seismic studies, travel time shift estimations have been used. This paper compared pre-stack and post-stack estimation of average velocity changes based on measured 4-dimensional travel time shifts. It is more practical to compare estimated velocity changes than the actual travel time changes, since the time shifts vary with offset for pre-stack time-lapse seismic analysis. It was concluded that the pre-stack method gives smaller velocity changes when estimated between two key horizons. Therefore, pre-stack travel time analysis in addition to conventional post-stack analysis is recommended. 6 refs., 12 figs

Comparison of source moment tensor recovered by diffraction stacking migration and source time reversal imaging

Science.gov (United States)

Zhang, Q.; Zhang, W.

2017-12-01

Diffraction stacking migration is an automatic location methods and widely used in microseismic monitoring of the hydraulic fracturing. It utilizes the stacking of thousands waveform to enhance signal-to-noise ratio of weak events. For surface monitoring, the diffraction stacking method is suffered from polarity reverse among receivers due to radiation pattern of moment source. Joint determination of location and source mechanism has been proposed to overcome the polarity problem but needs significantly increased computational calculations. As an effective method to recover source moment tensor, time reversal imaging based on wave equation can locate microseismic event by using interferometry on the image to extract source position. However, the time reversal imaging is very time consuming compared to the diffraction stacking location because of wave-equation simulation.In this study, we compare the image from diffraction stacking and time reversal imaging to check if the diffraction stacking can obtain similar moment tensor as time reversal imaging. We found that image produced by taking the largest imaging value at each point along time axis does not exhibit the radiation pattern, while with the same level of calculation efficiency, the image produced for each trial origin time can generate radiation pattern similar to time reversal imaging procedure. Thus it is potential to locate the source position by the diffraction stacking method for general moment tensor sources.

The computational optimization of heat exchange efficiency in stack chimneys

Energy Technology Data Exchange (ETDEWEB)

Van Goch, T.A.J.

2012-02-15

For many industrial processes, the chimney is the final step before hot fumes, with high thermal energy content, are discharged into the atmosphere. Tapping into this energy and utilizing it for heating or cooling applications, could improve sustainability, efficiency and/or reduce operational costs. Alternatively, an unused chimney, like the monumental chimney at the Eindhoven University of Technology, could serve as an 'energy channeler' once more; it can enhance free cooling by exploiting the stack effect. This study aims to identify design parameters that influence annual heat exchange in such stack chimney applications and optimize these parameters for specific scenarios to maximize the performance. Performance is defined by annual heat exchange, system efficiency and costs. The energy required for the water pump as compared to the energy exchanged, defines the system efficiency, which is expressed in an efficiency coefficient (EC). This study is an example of applying building performance simulation (BPS) tools for decision support in the early phase of the design process. In this study, BPS tools are used to provide design guidance, performance evaluation and optimization. A general method for optimization of simulation models will be studied, and applied in two case studies with different applications (heating/cooling), namely; (1) CERES case: 'Eindhoven University of Technology monumental stack chimney equipped with a heat exchanger, rejects heat to load the cold source of the aquifer system on the campus of the university and/or provides free cooling to the CERES building'; and (2) Industrial case: 'Heat exchanger in an industrial stack chimney, which recoups heat for use in e.g. absorption cooling'. The main research question, addressing the concerns of both cases, is expressed as follows: 'what is the optimal set of design parameters so heat exchange in stack chimneys is optimized annually for the cases in which a

Draught regulator with control flap lowers dew point, keeps stacks dry

Energy Technology Data Exchange (ETDEWEB)

Dreizler, U.; Dreizler, W.

1982-11-30

Draught regulators for auxiliary air are particularly important in older stacks operated with new boilers and burners. Owing to better ventilation during burner operation and standstill, the dew point of flue gases will be lowered so that water vapour condensation will be prevented. Postfitting of draught regulators will also help in stacks already damaged by condensation water. The draught regulator has a control flap for better control of auxiliary air supply.

Band engineering in transition metal dichalcogenides: Stacked versus lateral heterostructures

International Nuclear Information System (INIS)

Guo, Yuzheng; Robertson, John

2016-01-01

We calculate a large difference in the band alignments for transition metal dichalcogenide (TMD) heterojunctions when arranged in the stacked layer or lateral (in-plane) geometries, using direct supercell calculations. The stacked case follows the unpinned limit of the electron affinity rule, whereas the lateral geometry follows the strongly pinned limit of alignment of charge neutrality levels. TMDs therefore provide one of the few clear tests of band alignment models, whereas three-dimensional semiconductors give less stringent tests because of accidental chemical trends in their properties.

Operational measurements of stack flow rates in a nuclear power plant with ultrasonic anemometer

International Nuclear Information System (INIS)

Voelz, E.; Kirtzel, H.-J.; Ebenhoech, E.

2003-01-01

The calculation of the impact of radio nuclides within the surroundings of nuclear power stations requires quantitative measurements of the stack emission. As a standard method, propeller anemometers have been installed inside the stack, but due to the wear and tear of the moving parts in such conventional sensors the servicing and maintenance are costly and may cause restrictions in the operation of the stack. As an alternative to propeller anemometers ultrasonic sensors have been applied which employ no moving parts and are almost free of maintenance. Furthermore, any shifts in internal calibration parameters can be identified by the sensor electronics with on-line plausibility checks. The tests have proven that ultrasonic systems are able to measure adequately and reliably the flow inside the stack. (orig.)

MODIFYING A 60-YEAR-OLD STACK-SAMPLING SYSTEM TO MEET ANSI N13.1-1999 EQUIVALENCY

International Nuclear Information System (INIS)

SIMMONS, F.M.

2006-01-01

The 291-T-1 stack was constructed in 1944 to support ongoing missions associated with the Hanford Project. Recent changes in the plant mission required a revision to the existing license of the stack that was operating as a minor emission unit. The Environmental Protection Agency (EPA) and the Washington Department of Health (WDOH) deemed this revision to be a significant modification, thereby requiring the stack to operate to the ANSI N13.1-1999 sampling and monitoring requirements. Because the stack is similar to other stacks on the Hanford site, allowance was made by EPA to demonstrate equivalency to the ANSI standard via calculations in lieu of actual testing. Calculations were allowed for determining the deposition, nozzle transmission and aspiration ratios, but measurements were required for the stack flow coefficient of variation (COV). The equivalency determination was to be based on the requirements of Table 6 of the ANSI N13.1-1999 Standard

Parsing of the free energy of aromatic-aromatic stacking interactions in solution

Energy Technology Data Exchange (ETDEWEB)

Kostjukov, Viktor V.; Khomytova, Nina M. [Department of Physics, Sevastopol National Technical University, Sevastopol 99053, Crimea (Ukraine); Hernandez Santiago, Adrian A.; Tavera, Anna-Maria Cervantes; Alvarado, Julieta Salas [Faculty of Chemical Sciences, Autonomous University of Puebla, Puebla (Mexico); Evstigneev, Maxim P., E-mail: max_evstigneev@mail.ru [Department of Physics, Sevastopol National Technical University, Sevastopol 99053, Crimea (Ukraine)

2011-10-15

Graphical abstract: Highlights: > A protocol for decomposition of the free energy of aromatic stacking is developed. > The factors stabilizing/destabilizing stacking of aromatic molecules are defined. > Hydrophobic contribution is found to be dominant. - Abstract: We report an analysis of the energetics of aromatic-aromatic stacking interactions for 39 non-covalent reactions of self- and hetero-association of 12 aromatic molecules with different structures and charge states. A protocol for computation of the contributions to the total energy from various energetic terms has been developed and the results are consistent with experiment in 92% of all the systems studied. It is found that the contributions from hydrogen bonds and entropic factors are always unfavorable, whereas contributions from van-der-Waals, electrostatic and/or hydrophobic effects may lead to stabilizing or destabilizing factors depending on the system studied. The analysis carried out in this work provides an answer to the questions 'What forces stabilize/destabilize the stacking of aromatic molecules in aqueous-salt solution and what are their relative importance?'

Parsing of the free energy of aromatic-aromatic stacking interactions in solution

International Nuclear Information System (INIS)

Kostjukov, Viktor V.; Khomytova, Nina M.; Hernandez Santiago, Adrian A.; Tavera, Anna-Maria Cervantes; Alvarado, Julieta Salas; Evstigneev, Maxim P.

2011-01-01

Graphical abstract: Highlights: → A protocol for decomposition of the free energy of aromatic stacking is developed. → The factors stabilizing/destabilizing stacking of aromatic molecules are defined. → Hydrophobic contribution is found to be dominant. - Abstract: We report an analysis of the energetics of aromatic-aromatic stacking interactions for 39 non-covalent reactions of self- and hetero-association of 12 aromatic molecules with different structures and charge states. A protocol for computation of the contributions to the total energy from various energetic terms has been developed and the results are consistent with experiment in 92% of all the systems studied. It is found that the contributions from hydrogen bonds and entropic factors are always unfavorable, whereas contributions from van-der-Waals, electrostatic and/or hydrophobic effects may lead to stabilizing or destabilizing factors depending on the system studied. The analysis carried out in this work provides an answer to the questions 'What forces stabilize/destabilize the stacking of aromatic molecules in aqueous-salt solution and what are their relative importance?'

Determination of Fire Enviroment in Stacked Cargo Containers with Radioactive Materials Packages

Energy Technology Data Exchange (ETDEWEB)

Arviso, M.; Bobbe, J.G.; Dukart, R.D.; Koski, J.A.

1999-05-01

Results from a Fire Test with a three-by-three stack of standard 6 m long International Standards Organization shipping containers containing combustible fuels and empty radioactive materials packages are reported and discussed. The stack is intended to simulate fire conditions that could occur during on-deck stowage on container cargo ships. The fire is initated by locating the container stack adjacent to a 9.8 x 6 m pool fire. Temperatures of both cargoes (empty and simulated radioactive materials packages) and containers are recorded and reported. Observations on the duration, intensity and spread of the fire are discussed. Based on the results, models for simulation of fire exposure of radioactive materials packages in such fires are suggested.

Plants with stacked genetically modified events: to assess or not to assess?

Science.gov (United States)

Kok, Esther J; Pedersen, Jan; Onori, Roberta; Sowa, Slawomir; Schauzu, Marianna; De Schrijver, Adinda; Teeri, Teemu H

2014-02-01

The principles for the safety assessment of genetically modified (GM) organisms (GMOs) are harmonised worldwide to a large extent. There are, however, still differences between the European GMO regulations and the GMO regulations as they have been formulated in other parts of the world. One of these differences relates to the so-called 'stacked GM events', that is, GMOs, plants so far, where new traits are combined by conventional crossing of different GM plants. This paper advocates rethinking the current food/feed safety assessment of stacked GM events in Europe based on an analysis of different aspects that currently form the rationale for the safety assessment of stacked GM events. Copyright © 2013 Elsevier Ltd. All rights reserved.

Stack Memory Implementation and Analysis of Timing Constraint, Power and Memory using FPGA

DEFF Research Database (Denmark)

Thind, Vandana; Pandey, Nisha; Pandey, Bishwajeet

2017-01-01

real-time output, so that source used to realize the project is not wasted and get an energy efficient design. However, Stack memory is an approach in which information is entered and deleted from the stack memory segment in the pattern of last in first out mechanism. There are several ways...... of implementation of stack memory algorithm but virtex4 and virtex7 low voltage were considered to be the most efficient platforms for its operation. The developed system is energy efficient as the algorim ensures less memory utilization, less power consumption and short time for signal travel.......Abstract— in this work of analysis, stack memory algorithm is implemented on a number of FPGA platforms like virtex4, virtex5, virtex6, virtex6 low power and virtex7 low voltage and very detailed observations/investigations were made about timing constraint, memory and power dissipation. The main...

Stratigraphy and stable isotope geochemistry of the carbonate sequence from the Paraguay belt

International Nuclear Information System (INIS)

Santos, Roberto Ventura.; Alvarenga, Carlos Jose Souza de; Dantas, Elton Luiz

2001-01-01

Two main Neoproterozoic carbonate sequences occur central Brazil both of which are stratiphicaly above glacial derived sediments. An older carbonate sequence occurs over the Sao Francisco Craton and in the surrounding folded belts (Rio Preto, Aracuai Ribeira and Brasilia). These carbonates overlie glacial diamictites that were related to the 'Sturtian' event dated between 0.7 and 0.9 Ga (Toulkeridis et al. 1999, Santos et al., 2000). A second carbonate sequence is described in the Paraguay Belt and postdated Vendian/Varegian glaciation sediments from the end of the Neoproterozoic. This glacial event has been reported in many studies concerning the Gondwana and the Laurentia supercontinent (Trompette, 1996; Condon and Prave, 2000; Myrow and Kaufman, 1999). In the Paraguay Belt the Vendian- Varangian glaciation rocks are characterized by a glaciomarine sequence, that occur at the border of the basin, and by glacial derived turbidites deposits, that occur in the deeper parts of the basin (Alvarenga and Trompette, 1992). Near the city of Corumba this glaciomarine sequence is overlaid by carbonate rocks containing Ediacaran-like fauna in which has been described Corumbella werneri and Cloudina Lucianoi (Hahn et al., 1982; Walde et al., 1982; Zaine and Fairchild, 1985; 1987). These carbonates have been interpreted as cap carbonates and the age of their fossils have been attributed to the Vendian Superior (590-545 MA) (Alvarenga and Trompette, 1992, Trompette 1996). Isotope stratigraphy studies have been widely used to study cap carbonate rocks that overlie Sturtian and Vendian- Varagian glaciogenic rocks. Stratigraphic correlation of these units is usually difficult because their lack fossils and there is no precise dating method that could be applied to these rocks. Hence, most studies concerning Neoproterozoic carbonates have concentrated on their stromatilites and microfossils content as well as on carbon isotope variations. In the present study, we present new carbon

Online estimation of internal stack temperatures in solid oxide fuel cell power generating units

Science.gov (United States)

Dolenc, B.; Vrečko, D.; Juričić, Ɖ.; Pohjoranta, A.; Pianese, C.

2016-12-01

Thermal stress is one of the main factors affecting the degradation rate of solid oxide fuel cell (SOFC) stacks. In order to mitigate the possibility of fatal thermal stress, stack temperatures and the corresponding thermal gradients need to be continuously controlled during operation. Due to the fact that in future commercial applications the use of temperature sensors embedded within the stack is impractical, the use of estimators appears to be a viable option. In this paper we present an efficient and consistent approach to data-driven design of the estimator for maximum and minimum stack temperatures intended (i) to be of high precision, (ii) to be simple to implement on conventional platforms like programmable logic controllers, and (iii) to maintain reliability in spite of degradation processes. By careful application of subspace identification, supported by physical arguments, we derive a simple estimator structure capable of producing estimates with 3% error irrespective of the evolving stack degradation. The degradation drift is handled without any explicit modelling. The approach is experimentally validated on a 10 kW SOFC system.

Cell layer level generalized dynamic modeling of a PEMFC stack using VHDL-AMS language

Energy Technology Data Exchange (ETDEWEB)

Gao, Fei; Blunier, Benjamin; Miraoui, Abdellatif; El-Moudni, Abdellah [Transport and Systems Laboratory (SeT) - EA 3317/UTBM, University of Technology of Belfort-Montbeliard, Rue Thierry Mieg, 90000 Belfort (France)

2009-07-15

A generalized, cell layer scale proton exchange membrane fuel cell (PEMFC) stack dynamic model is presented using VHDL-AMS (IEEE standard Very High Speed Integrated Circuit Hardware Description Language-Analog and Mixed-Signal Extensions) modeling language. A PEMFC stack system is a complex energy conversion system that covers three main energy domains: electrical, fluidic and thermal. The first part of this work shows the performance and the advantages of VHDL-AMS language when modeling such a complex system. Then, using the VHDL-AMS modeling standards, an electrical domain model, a fluidic domain model and a thermal domain model of the PEMFC stack are coupled and presented together. Thus, a complete coupled multi-domain fuel cell stack 1-D dynamic model is given. The simulation results are then compared with a Ballard 1.2 kW NEXA fuel cell system, and show a great agreement between the simulation and experimentation. This complex multi-domain VHDL-AMS stack model can be used for a model based control design or a Hardware-In-the-Loop application. (author)

Polarization-insensitive optical gain characteristics of highly stacked InAs/GaAs quantum dots

International Nuclear Information System (INIS)

Kita, Takashi; Suwa, Masaya; Kaizu, Toshiyuki; Harada, Yukihiro

2014-01-01

The polarized optical gain characteristics of highly stacked InAs/GaAs quantum dots (QDs) with a thin spacer layer fabricated on an n + -GaAs (001) substrate were studied in the sub-threshold gain region. Using a 4.0-nm-thick spacer layer, we realized an electronically coupled QD superlattice structure along the stacking direction, which enabled the enhancement of the optical gain of the [001] transverse-magnetic (TM) polarization component. We systematically studied the polarized electroluminescence properties of laser devices containing 30 and 40 stacked InAs/GaAs QDs. The net modal gain was analyzed using the Hakki-Paoli method. Owing to the in-plane shape anisotropy of QDs, the polarization sensitivity of the gain depends on the waveguide direction. The gain showing polarization isotropy between the TM and transverse-electric polarization components is high for the [110] waveguide structure, which occurs for higher amounts of stacked QDs. Conversely, the isotropy of the [−110] waveguide is easily achieved even if the stacking is relatively low, although the gain is small.

Physically Connected Stacked Patch Antenna Design with 100% Bandwidth

KAUST Repository

Klionovski, Kirill; Shamim, Atif

2017-01-01

Typically, stacked patch antennas are parasitically coupled and provide larger bandwidth than a single patch antenna. Here, we show a stacked patch antenna design where square patches with semi-circular cutouts are physically connected to each other. This arrangement provides 100% bandwidth from 23.9–72.2 GHz with consistent high gain (5 dBi or more) across the entire bandwidth. In another variation, a single patch loaded with a superstrate provides 83.5% bandwidth from 25.6–62.3 GHz. The mechanism of bandwidth enhancement is explained through electromagnetic simulations. Measured reflection coefficient, radiation patterns and gain results confirm the extremely wideband performance of the design.

Physically Connected Stacked Patch Antenna Design with 100% Bandwidth

KAUST Repository

Klionovski, Kirill

2017-11-01

Typically, stacked patch antennas are parasitically coupled and provide larger bandwidth than a single patch antenna. Here, we show a stacked patch antenna design where square patches with semi-circular cutouts are physically connected to each other. This arrangement provides 100% bandwidth from 23.9–72.2 GHz with consistent high gain (5 dBi or more) across the entire bandwidth. In another variation, a single patch loaded with a superstrate provides 83.5% bandwidth from 25.6–62.3 GHz. The mechanism of bandwidth enhancement is explained through electromagnetic simulations. Measured reflection coefficient, radiation patterns and gain results confirm the extremely wideband performance of the design.

Anti-solvent derived non-stacked reduced graphene oxide for high performance supercapacitors.

Science.gov (United States)

Yoon, Yeoheung; Lee, Keunsik; Baik, Chul; Yoo, Heejoun; Min, Misook; Park, Younghun; Lee, Sae Mi; Lee, Hyoyoung

2013-08-27

An anti-solvent for graphene oxide (GO), hexane, is introduced to increase the surface area and the pore volume of the non-stacked GO/reduced GO 3D structure and allows the formation of a highly crumpled non-stacked GO powder, which clearly shows ideal supercapacitor behavior. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An intuitive graphical webserver for multiple-choice protein sequence search.

Science.gov (United States)

Banky, Daniel; Szalkai, Balazs; Grolmusz, Vince

2014-04-10

Every day tens of thousands of sequence searches and sequence alignment queries are submitted to webservers. The capitalized word "BLAST" becomes a verb, describing the act of performing sequence search and alignment. However, if one needs to search for sequences that contain, for example, two hydrophobic and three polar residues at five given positions, the query formation on the most frequently used webservers will be difficult. Some servers support the formation of queries with regular expressions, but most of the users are unfamiliar with their syntax. Here we present an intuitive, easily applicable webserver, the Protein Sequence Analysis server, that allows the formation of multiple choice queries by simply drawing the residues to their positions; if more than one residue are drawn to the same position, then they will be nicely stacked on the user interface, indicating the multiple choice at the given position. This computer-game-like interface is natural and intuitive, and the coloring of the residues makes possible to form queries requiring not just certain amino acids in the given positions, but also small nonpolar, negatively charged, hydrophobic, positively charged, or polar ones. The webserver is available at http://psa.pitgroup.org. Copyright © 2014 Elsevier B.V. All rights reserved.

Very Weak Signals (VWS detected by stacking method according to different astronomical periodicities (HiCum

Directory of Open Access Journals (Sweden)

M. van Ruymbeke

2007-11-01

Full Text Available A stacking method to detect very weak signals is introduced in this paper. This method is to stack observed data in different well known periodicities according to the astronomical clock since majority geophysical observations are time based. We validated this method by applying it in four different cases. Interactions behind the observed parameters become obviously after it is stacked in two diurnal and semidiurnal tidal periodical waves. Amplitude and phase variations will be also measurable when a sliding windows stacking is used. This could be an important reference to find precursors before some earthquakes and volcanic events, corresponding to attenuations of medium patterns.

Theoretical analysis of stack gas emission velocity measurement by optical scintillation

International Nuclear Information System (INIS)

Yang Yang; Dong Feng-Zhong; Ni Zhi-Bo; Pang Tao; Zeng Zong-Yong; Wu Bian; Zhang Zhi-Rong

2014-01-01

Theoretical analysis for an online measurement of the stack gas flow velocity based on the optical scintillation method with a structure of two parallel optical paths is performed. The causes of optical scintillation in a stack are first introduced. Then, the principle of flow velocity measurement and its mathematical expression based on cross correlation of the optical scintillation are presented. The field test results show that the flow velocity measured by the proposed technique in this article is consistent with the value tested by the Pitot tube. It verifies the effectiveness of this method. Finally, by use of the structure function of logarithmic light intensity fluctuations, the theoretical explanation of optical scintillation spectral characteristic in low frequency is given. The analysis of the optical scintillation spectrum provides the basis for the measurement of the stack gas flow velocity and particle concentration simultaneously. (general)

The collapse of stacking-fault tetrahedra by interaction with gliding dislocations

International Nuclear Information System (INIS)

Matsukawa, Y.; Osetsky, Yu.N.; Stoller, R.E.; Zinkle, S.J.

2005-01-01

The collapse of stacking-fault tetrahedra (SFT) by gliding dislocations was observed in in situ straining experiments in a transmission electron microscope (TEM). A stacking-fault tetrahedron was collapsed by intersection with a gliding perfect dislocation: only the base portion divided by the gliding plane of the dislocation annihilated, while the apex portion remained intact. As a result of analysis on evolution of atom configuration induced by intersection with perfect dislocation in SFT, it was found that an unusual atom configuration inevitably appeared in one of the ledges formed on stacking-fault planes, which is traditionally called I-ledge: the atoms on adjacent (1 1 1) planes were overlapping each other. The overlapping configuration provides a strong repulsive force, being a conceivable driving force to induce a chain reaction of atom displacements that collapses the SFT base portion

Report on the calculations of the height of the stack for PUSPATI laboratories

Energy Technology Data Exchange (ETDEWEB)

1981-03-01

This report outlines the method used in the calculation of the required stack height in order to ensure adequate dispersion and dilution of radioactive materials emitted through the stack under routine as well as accident conditions. The calculations were based on the most predominant radioactive material 1-131, possibly to be discharged from the establishment. Some general assumptions were considered and these include maximum activity of 1-131, production efficiency, filter decontamination factor, MPCa value, topography, meteorological conditions, building wake effect, downwash and plume rise. The calculations have indicated that a stack of 40 meters in height is adequate.

Band Gap Grading of Stacked Cu(In,Ga)S{sub 2} Thin Films

Energy Technology Data Exchange (ETDEWEB)

Jeong, Seonghyun; Sohn, So Hyeong; Shim, Hyeong Seop; Park, Seung Min; Song, Jae Kyu [Kyung Hee University, Seoul (Korea, Republic of); Min, Byoung Koun [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

2016-01-15

The band gap energy of CIGS, which depends on the composition variation and strain effect, can influence the collection and recombination of photocarriers. The solar cell efficiency is improved by the graded band gap in the absorber layer due to the enhanced carrier collection and the reduced carrier recombination. In our previous study, the photovoltaic performance of solar cells was affected by the stacking combination of layers, where the solar cell with dense-bottom and porous-top layers showed better performance than that with a reversely stacked structure. We studied the stacking effect of CIGS thin films. The stacking did not change E {sub g} of each layer, which led to the double grading of E {sub g} along the depth of the stacked films, mainly due to the difference in E {sub g} between the dense and porous layers. The higher degree of the grading in A+B+A improved J {sub sc}. However, the higher density of the defect states in A+B+A reduced V {sub oc}, which was inferred by the short lifetime of the carriers and the broad bandwidth of photoluminescence. Overall, the efficiency of A+B+A was only slightly improved compared to that of B+A.

High power multiple wavelength diode laser stack for DPSSL application without temperature control

Science.gov (United States)

Hou, Dong; Yin, Xia; Wang, Jingwei; Chen, Shi; Zhan, Yun; Li, Xiaoning; Fan, Yingmin; Liu, Xingsheng

2018-02-01

High power diode laser stack is widely used in pumping solid-state laser for years. Normally an integrated temperature control module is required for stabilizing the output power of solid-state laser, as the output power of the solid-state laser highly depends on the emission wavelength and the wavelength shift of diode lasers according to the temperature changes. However the temperature control module is inconvenient for this application, due to its large dimension, high electric power consumption and extra adding a complicated controlling system. Furthermore, it takes dozens of seconds to stabilize the output power when the laser system is turned on. In this work, a compact hard soldered high power conduction cooled diode laser stack with multiple wavelengths is developed for stabilizing the output power of solid-state laser in a certain temperature range. The stack consists of 5 laser bars with the pitch of 0.43mm. The peak output power of each bar in the diode laser stack reaches as much as 557W and the combined lasing wavelength spectrum profile spans 15nm. The solidstate laser, structured with multiple wavelength diode laser stacks, allows the ambient temperature change of 65°C without suddenly degrading the optical performance.

Dynamic Analysis of Load Operations of Two-Stage SOFC Stacks Power Generation System

Directory of Open Access Journals (Sweden)

Paulina Pianko-Oprych

2017-12-01

Full Text Available The main purpose of this paper was to develop a complete dynamic model of a power generation system based on two serially connected solid oxide fuel cell stacks. The uniqueness of this study lies in a different number of fuel cells in the stacks. The model consists of the electrochemical model, mass and energy balance equations implemented in MATLAB Simulink environment. Particular attention has been paid to the analysis of the transient response of the reformers, fuel cells and the burner. The dynamic behavior of the system during transient conditions was investigated by load step changing. The model evaluates electrical and thermal responses of the system at variable drawn current. It was found that a decrease of 40% in the 1st stage and 2nd solid oxide fuel cell (SOFC stacks drawn current caused both stacks temperature to drop by 2%. An increase of the cell voltage for the 1st and 2nd SOFC stacks led to very fast steam reformer response combined with a slight decrease in reformer temperature, while a considerable burner temperature increase of 70 K can be observed. Predictions of the model provide the basic insight into the operation of the power generation-based SOFC system during various transients and support its further design modifications.

Intermittent turbulence and oscillations in the stable boundary layer over land

NARCIS (Netherlands)

Wiel, van de B.

2002-01-01

As the title of this thesis indicates, our main subject of interest is: "Intermittent turbulence and oscillation in the stable boundary layer over land". As such, this theme connects the different chapters. Here, intermittent turbulence is defined as a sequence of events were 'burst' of

Molecular Characterization of Transgenic Events Using Next Generation Sequencing Approach.

Science.gov (United States)

Guttikonda, Satish K; Marri, Pradeep; Mammadov, Jafar; Ye, Liang; Soe, Khaing; Richey, Kimberly; Cruse, James; Zhuang, Meibao; Gao, Zhifang; Evans, Clive; Rounsley, Steve; Kumpatla, Siva P

2016-01-01

Demand for the commercial use of genetically modified (GM) crops has been increasing in light of the projected growth of world population to nine billion by 2050. A prerequisite of paramount importance for regulatory submissions is the rigorous safety assessment of GM crops. One of the components of safety assessment is molecular characterization at DNA level which helps to determine the copy number, integrity and stability of a transgene; characterize the integration site within a host genome; and confirm the absence of vector DNA. Historically, molecular characterization has been carried out using Southern blot analysis coupled with Sanger sequencing. While this is a robust approach to characterize the transgenic crops, it is both time- and resource-consuming. The emergence of next-generation sequencing (NGS) technologies has provided highly sensitive and cost- and labor-effective alternative for molecular characterization compared to traditional Southern blot analysis. Herein, we have demonstrated the successful application of both whole genome sequencing and target capture sequencing approaches for the characterization of single and stacked transgenic events and compared the results and inferences with traditional method with respect to key criteria required for regulatory submissions.

Molecular Characterization of Transgenic Events Using Next Generation Sequencing Approach.

Directory of Open Access Journals (Sweden)

Satish K Guttikonda

Full Text Available Demand for the commercial use of genetically modified (GM crops has been increasing in light of the projected growth of world population to nine billion by 2050. A prerequisite of paramount importance for regulatory submissions is the rigorous safety assessment of GM crops. One of the components of safety assessment is molecular characterization at DNA level which helps to determine the copy number, integrity and stability of a transgene; characterize the integration site within a host genome; and confirm the absence of vector DNA. Historically, molecular characterization has been carried out using Southern blot analysis coupled with Sanger sequencing. While this is a robust approach to characterize the transgenic crops, it is both time- and resource-consuming. The emergence of next-generation sequencing (NGS technologies has provided highly sensitive and cost- and labor-effective alternative for molecular characterization compared to traditional Southern blot analysis. Herein, we have demonstrated the successful application of both whole genome sequencing and target capture sequencing approaches for the characterization of single and stacked transgenic events and compared the results and inferences with traditional method with respect to key criteria required for regulatory submissions.

Canonical, stable, general mapping using context schemes.

Science.gov (United States)

Novak, Adam M; Rosen, Yohei; Haussler, David; Paten, Benedict

2015-11-15

Sequence mapping is the cornerstone of modern genomics. However, most existing sequence mapping algorithms are insufficiently general. We introduce context schemes: a method that allows the unambiguous recognition of a reference base in a query sequence by testing the query for substrings from an algorithmically defined set. Context schemes only map when there is a unique best mapping, and define this criterion uniformly for all reference bases. Mappings under context schemes can also be made stable, so that extension of the query string (e.g. by increasing read length) will not alter the mapping of previously mapped positions. Context schemes are general in several senses. They natively support the detection of arbitrary complex, novel rearrangements relative to the reference. They can scale over orders of magnitude in query sequence length. Finally, they are trivially extensible to more complex reference structures, such as graphs, that incorporate additional variation. We demonstrate empirically the existence of high-performance context schemes, and present efficient context scheme mapping algorithms. The software test framework created for this study is available from https://registry.hub.docker.com/u/adamnovak/sequence-graphs/. anovak@soe.ucsc.edu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

De novo SNP calling from RAD sequences for a mink (Neovison vison) specific genotyping assay

DEFF Research Database (Denmark)

Thirstrup, Janne Pia; Pujolar, José Martin; Larsen, Peter F

2013-01-01

mink from Brown and Black color types were obtained. A mean of 49,789,860.2 (± 9,813,587.2) raw reads of high quality per sample were sequenced. SNPs were called using the software pipeline Stacks. The populations program was used to estimate population structure and genetic divergence between the two...

Stack monitor for the Proof-of-Breeding Project

International Nuclear Information System (INIS)

Fergus, R.W.

1985-01-01

This stack monitor system is a coordinated arrangement of hardware and software to monitor four hot cells (8 stacks) during the fuel dissection for the Proof-of-Breeding Project. The cell monitors, which are located in fan lofts, contain a microprocessor, radiation detectors, air flow sensors, and air flow control equipment. Design criteria included maximizing microprocessor control while minimizing the hardware complexity. The monitors have been programmed to produce concentration and total activity release data based on several detector measurements and flow rates. Although each monitor can function independently, a microcomputer can also be used to control each cell monitor including reprogramming if necessary. All programming is software, as opposed to firmware, with machine language for compactness in the cell monitors and Basic language for adaptability in the microcomputer controller

A novel approach to model the transient behavior of solid-oxide fuel cell stacks

Science.gov (United States)

Menon, Vikram; Janardhanan, Vinod M.; Tischer, Steffen; Deutschmann, Olaf

2012-09-01

This paper presents a novel approach to model the transient behavior of solid-oxide fuel cell (SOFC) stacks in two and three dimensions. A hierarchical model is developed by decoupling the temperature of the solid phase from the fluid phase. The solution of the temperature field is considered as an elliptic problem, while each channel within the stack is modeled as a marching problem. This paper presents the numerical model and cluster algorithm for coupling between the solid phase and fluid phase. For demonstration purposes, results are presented for a stack operated on pre-reformed hydrocarbon fuel. Transient response to load changes is studied by introducing step changes in cell potential and current. Furthermore, the effect of boundary conditions and stack materials on response time and internal temperature distribution is investigated.

Study on component interface evolution of a solid oxide fuel cell stack after long term operation

Science.gov (United States)

Yang, Jiajun; Huang, Wei; Wang, Xiaochun; Li, Jun; Yan, Dong; Pu, Jian; Chi, Bo; Li, Jian

2018-05-01

A 5-cell solid oxide fuel cell (SOFC) stack with external manifold structure is assembled and underwent a durability test with an output of 250 W for nearly 4400 h when current density and operating temperature are 355 mA/cm2 and 750 °C. Cells used in the stack are anode-supported cells (ASC) with yttria-stabilized zirconia (YSZ) electrolytes, Ni/YSZ hydrogen electrodes, and YSZ based composite cathode. The dimension of the cell is 150 × 150 mm (active area: 130 × 130 mm). Ceramic-glass sealant is used in the stack to keep the gas tightness between cells, interconnects and manifolds. Pure hydrogen and dry air are used as fuel and oxidant respectively. The stack has a maximum output of 340 W at 562 mA/cm2 current density at 750 °C. The stack shows a degradation of 1.5% per 1000 h during the test with 2 thermal cycles to room temperature. After the test, the stack was dissembled and examined. The relationship between microstructure changes of interfaces and degradation in the stack are discussed. The microstructure evolution of interfaces between electrode, contact material and current collector are unveiled and their relationship with the degradation is discussed.

Assessment for potential radionuclide emissions from stacks and diffuse and fugitive sources on the Hanford Site

International Nuclear Information System (INIS)

Davis, W.E.; Schmidt, J.W.; Gleckler, B.P.; Rhoads, K.

1995-06-01

By using the six EPA-approved methods, instead of only the original back calculation method for assessing the 84 WHC registered stacks, the number of stacks requiring continuous monitoring was reduced from 32 to 19 stacks. The intercomparison between results showed that no correlation existed between back calculations and release fractions. Also the NDA, upstream air samples, and powder release fraction method results were at least three orders of magnitude lower then the back calculations results. The most surprising results of the assessment came from NDA. NDA was found to be an easy method for assessing potential emissions. For the nine stacks assessed by NDA, all nine of the stacks would have required continuous monitoring when assessed by back calculations. However, when NDA was applied all stacks had potential emissions that would cause an EDE below the > 0.1 mrem/y standard. Apparent DFs for the HEPA filter systems were calculated for eight nondesignated stacks with emissions above the detection limit. These apparent DFs ranged from 0.5 to 250. The EDE dose to the MEI was calculated to be 0.028 mrem/y for diffuse and fugitive emissions from the Hanford Sited. This is well below the > 0.1 mrem/y standard

Investigation of Ruthenium Dissolution in Advanced Membrane Electrode Assemblies for Direct Methanol Based Fuel Cells Stacks

Science.gov (United States)

Valdez, T. I.; Firdosy, S.; Koel, B. E.; Narayanan, S. R.

2005-01-01

This viewgraph presentation gives a detailed review of the Direct Methanol Based Fuel Cell (DMFC) stack and investigates the Ruthenium that was found at the exit of the stack. The topics include: 1) Motivation; 2) Pathways for Cell Degradation; 3) Cell Duration Testing; 4) Duration Testing, MEA Analysis; and 5) Stack Degradation Analysis.

Measurements of the LHCb software stack on the ARM architecture

International Nuclear Information System (INIS)

Kartik, S Vijay; Couturier, Ben; Clemencic, Marco; Neufeld, Niko

2014-01-01

The ARM architecture is a power-efficient design that is used in most processors in mobile devices all around the world today since they provide reasonable compute performance per watt. The current LHCb software stack is designed (and thus expected) to build and run on machines with the x86/x86 6 4 architecture. This paper outlines the process of measuring the performance of the LHCb software stack on the ARM architecture – specifically, the ARMv7 architecture on Cortex-A9 processors from NVIDIA and on full-fledged ARM servers with chipsets from Calxeda – and makes comparisons with the performance on x86 6 4 architectures on the Intel Xeon L5520/X5650 and AMD Opteron 6272. The paper emphasises the aspects of performance per core with respect to the power drawn by the compute nodes for the given performance – this ensures a fair real-world comparison with much more 'powerful' Intel/AMD processors. The comparisons of these real workloads in the context of LHCb are also complemented with the standard synthetic benchmarks HEPSPEC and Coremark. The pitfalls and solutions for the non-trivial task of porting the source code to build for the ARMv7 instruction set are presented. The specific changes in the build process needed for ARM-specific portions of the software stack are described, to serve as pointers for further attempts taken up by other groups in this direction. Cases where architecture-specific tweaks at the assembler lever (both in ROOT and the LHCb software stack) were needed for a successful compile are detailed – these cases are good indicators of where/how the software stack as well as the build system can be made more portable and multi-arch friendly. The experience gained from the tasks described in this paper are intended to i) assist in making an informed choice about ARM-based server solutions as a feasible low-power alternative to the current compute nodes, and ii) revisit the software design and build system for portability and