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Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
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1

Nucleic Acid Standards | Base Pair Geometry  

NLE Websites -- All DOE Office Websites (Extended Search)

A Standard Reference Frame for the Description A Standard Reference Frame for the Description of Nucleic Acid Base-pair Geometry Table 1. Cartesian coordinates of non-hydrogen atoms in the standard reference frames of the five common nitrogenous bases Atom Base x(Å) y(Å) z(Å) Adenine ATOM 1 C1' A A 1 -2.479 5.346 0.000 ATOM 2 N9 A A 1 -1.291 4.498 0.000 ATOM 3 C8 A A 1 0.024 4.897 0.000 ATOM 4 N7 A A 1 0.877 3.902 0.000 ATOM 5 C5 A A 1 0.071 2.771 0.000 ATOM 6 C6 A A 1 0.369 1.398 0.000 ATOM 7 N6 A A 1 1.611 0.909 0.000 ATOM 8 N1 A A 1 -0.668 0.532 0.000 ATOM 9 C2 A A 1 -1.912 1.023 0.000 ATOM 10 N3 A A 1 -2.320 2.290 0.000

2

Method for sequencing DNA base pairs  

DOE Patents (OSTI)

The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source. 6 figures.

Sessler, A.M.; Dawson, J.

1993-12-14T23:59:59.000Z

3

Improved method for sequencing DNA base pairs  

DOE Patents (OSTI)

The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source. 1 ref.

Sessler, A.M.; Dawson, J.

1990-12-31T23:59:59.000Z

4

Improved method for sequencing DNA base pairs  

DOE Patents (OSTI)

The base pairs of a DNA structure are sequenced with the use of a scanning tunneling microscope (STM). The DNA structure is scanned by the STM probe tip, and, as it is being scanned, the DNA structure is separately subjected to a sequence of infrared radiation from four different sources, each source being selected to preferentially excite one of the four different bases in the DNA structure. Each particular base being scanned is subjected to such sequence of infrared radiation from the four different sources as that particular base is being scanned. The DNA structure as a whole is separately imaged for each subjection thereof to radiation from one only of each source. 1 ref.

Sessler, A.M.; Dawson, J.

1990-01-01T23:59:59.000Z

5

Nucleic Acid Standards - Standard Ref. Frame  

NLE Websites -- All DOE Office Websites (Extended Search)

Standard Reference Standard Reference Standard Reference Frame Supplemental Information Ideal Geometries X-PLOR Parameters Valence Geometries RNA Ontology Consortium mmCIF Resources PDBML Resources A Standard Reference Frame for the Description of Nucleic Acid Base-pair Geometry A common point of reference is needed to describe the three-dimensional arrangements of bases and base pairs in nucleic acid structures. [1]. For example, parts of a structure, which appear "normal" according to one computational scheme, may be highly unusual according to another and vice versa. It is thus difficult to carry out comprehensive comparisons of nucleic acid structures and to pinpoint unique conformational features in individual structures. In order to resolve these issues, a group of

6

Altering the Electrostatic Potential in the Major Groove: Thermodynamic and Structural Characterization of 7-Deaza-2;#8242;-deoxyadenosine:dT Base Pairing in DNA  

Science Conference Proceedings (OSTI)

As part of an ongoing effort to explore the effect of major groove electrostatics on the thermodynamic stability and structure of DNA, a 7-deaza-2'-deoxyadenosine:dT (7-deaza-dA:dT) base pair in the Dickerson-Drew dodecamer (DDD) was studied. The removal of the electronegative N7 atom on dA and the replacement with an electropositive C-H in the major groove was expected to have a significant effect on major groove electrostatics. The structure of the 7-deaza-dA:dT base pair was determined at 1.1 {angstrom} resolution in the presence of Mg{sup 2+}. The 7-deaza-dA, which is isosteric for dA, had minimal effect on the base pairing geometry and the conformation of the DDD in the crystalline state. There was no major groove cation association with the 7-deaza-dA heterocycle. In solution, circular dichroism showed a positive Cotton effect centered at 280 nm and a negative Cotton effect centered at 250 nm that were characteristic of a right-handed helix in the B-conformation. However, temperature-dependent NMR studies showed increased exchange between the thymine N3 imino proton of the 7-deaza-dA:dT base pair and water, suggesting reduced stacking interactions and an increased rate of base pair opening. This correlated with the observed thermodynamic destabilization of the 7-deaza-dA modified duplex relative to the DDD. A combination of UV melting and differential scanning calorimetry experiments were conducted to evaluate the relative contributions of enthalpy and entropy in the thermodynamic destabilization of the DDD. The most significant contribution arose from an unfavorable enthalpy term, which probably results from less favorable stacking interactions in the modified duplex, which was accompanied by a significant reduction in the release of water and cations from the 7-deaza-dA modified DNA.

Kowal, Ewa A.; Ganguly, Manjori; Pallan, Pradeep S.; Marky, Luis A.; Gold, Barry; Egli, Martin; Stone, Michael P. (Pitt); (Vanderbilt); (Nebraska-Med)

2012-02-15T23:59:59.000Z

7

QM/MM Lineshape Simulation of the Hydrogen-bonded Uracil NH Stretching Vibration of the Adenine:Uracil Base Pair in CDCl$_3$  

E-Print Network (OSTI)

A hybrid Car-Parrinello QM/MM molecular dynamics simulation has been carried out for the Watson-Crick base pair of 9-ethyl-8-phenyladenine and 1-cyclohexyluracil in deuterochloroform solution at room temperature. The resulting trajectory is analyzed putting emphasis on the N-H$...$N Hydrogen bond geometry. Using an empirical correlation between the $\\NN$-distance and the fundamental NH-stretching frequency, the time-dependence of this energy gap along the trajectory is obtained. From the gap-correlation function we determine the infrared absorption spectrum using lineshape theory in combination with a multimode oscillator model. The obtained average transition frequency and the width of the spectrum is in reasonable agreement with recent experimental data.

Yan, Yun-an; Khn, Oliver

2008-01-01T23:59:59.000Z

8

Ultrafast deactivation processes in the 2-aminopyridine dimer and the adenine-thymine base pair: Similarities and differences  

SciTech Connect

2-aminopyridine dimer has frequently been used as a model system for studying photochemistry of DNA base pairs. We examine here the relevance of 2-aminopyridine dimer for a Watson-Crick adenine-thymine base pair by studying UV-light induced photodynamics along two main hydrogen bridges after the excitation to the localized {sup 1}{pi}{pi}* excited-state. The respective two-dimensional potential-energy surfaces have been determined by time-dependent density functional theory with Coulomb-attenuated hybrid exchange-correlation functional (CAM-B3LYP). Different mechanistic aspects of the deactivation pathway have been analyzed and compared in detail for both systems, while the related reaction rates have also be obtained from Monte Carlo kinetic simulations. The limitations of the 2-aminopyridine dimer as a model system for the adenine-thymine base pair are discussed.

Ai Yuejie; Zhang Feng [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, S-10691 Stockholm (Sweden); Cui Ganglong; Fang Weihai [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Luo Yi [Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, S-10691 Stockholm (Sweden); Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2010-08-14T23:59:59.000Z

9

Nucleic Acid Standards - Program List  

NLE Websites -- All DOE Office Websites (Extended Search)

List of Programs and References List of Programs and References CEHS M. A. El Hassan & C. R. Calladine (1995). ``The Assessment of the Geometry of Dinucleotide Steps in Double-Helical DNA: A New Local Calculation Scheme.'' J. Mol. Biol. 251, 648-664. X. J. Lu, M. A. El Hassan & C. A. Hunter (1997). ``Structure and Conformation of Helical Nucleic Acids: Analysis Program (SCHNAaP).''J. Mol. Biol. 273, 668-680. CompDNA (Please refer to Dr. Andrey A. Gorin: agor@sbnmr1.ski.mskcc.org OR Dr. Victor B. Zhurkin: zhurkin@lmmb.nci.nih.gov) A. A. Gorin, V. B. Zhurkin & W. K. Olson (1995). ``B-DNA Twisting Correlates with Base-pair Morphology.'' J. Mol. Biol. 247, 34-48. K. M. Kosikov, A. A. Gorin, V. B. Zhurkin & W. K. Olson (1999). ``DNA Stretching and Compression: Large-scale Simulations of Double Helical

10

Parabolic geometries BGG sequences  

E-Print Network (OSTI)

Parabolic geometries BGG sequences Prolongation procedures BGG Sequences and Geometric sequences and overdetermined systems #12;Parabolic geometries BGG sequences Prolongation procedures Parabolic geometries are a large class of differential geometric structures, which can be described

Drmota, Michael

11

Twistors to twisted geometries  

Science Conference Proceedings (OSTI)

In a previous paper we showed that the phase space of loop quantum gravity on a fixed graph can be parametrized in terms of twisted geometries, quantities describing the intrinsic and extrinsic discrete geometry of a cellular decomposition dual to the graph. Here we unravel the origin of the phase space from a geometric interpretation of twistors.

Freidel, Laurent [Perimeter Institute for Theoretical Physics, 31 Caroline Street N, ON N2L 2Y5, Waterloo (Canada); Speziale, Simone [Centre de Physique Theorique, CNRS-Luminy Case 907, 13288 Marseille Cedex 09 (France)

2010-10-15T23:59:59.000Z

12

Asymmetric Nondegenerate Geometry  

E-Print Network (OSTI)

Nondegenerate geometry (T-geometry) with nonsymmetric world function is considered. In application to the space-time geometry the asymmetry of world function means that the past and the future are not equivalent geometrically. T-geometry is described in terms of finite point subspaces and world function between pairs of points of these subsets, i.e. in the language which is immanent to geometry and free of external means of description (coordinates, curves). Such a description appears to be simple and effective even in the case of complicated T-geometry. Antisymmetric component of the world function generates appearance of additional metric fields. This leads to appearance of three sorts of Christoffel symbols and three sorts of geodesics. Three sorts of the first order tubes (future, past and neutral) appear. If the fields connected with the antisymmetric component are strong enough, the timelike first order tube has a finite length in the timelike direction. It was shown earler that the symmetric T-geometry explains non-relativistic quantum effects without a reference to principles of quantum mechanics. One should expect that nonsymmetric space-time T-geometry is also characteristic for microcosm, and it will be useful in the elementary particle theory, because there is a series of unexpected associations. First order tubes are associated with world tubes of closed strings. Antisymmetry is associated with supersymmetry. Three sorts of tubes are associated with three sorts of quarks. Limitation of the tube in time direction is associated with confinement. At any rate, the space-time T-geometry with additional parameters has more capacities, than usual Riemannian geometry.

Yuri Rylov

2002-05-07T23:59:59.000Z

13

acid  

Office of Legacy Management (LM)

Acid/Pueblo Canyon, New Mexico, Site is Acid/Pueblo Canyon, New Mexico, Site is located near the town of Los Alamos, New Mexico, approximately 25 miles northwest of Santa Fe and 60 miles north-northeast of Albuquerque. The site is accessible from Canyon Road, which runs just south of the former waste treatment plant. The plant was situated on a mesa that forms the south rim of Acid Canyon. Acid Canyon is a small tributary near the head

14

Nucleic Acid Standards - Standard Ref. Frame  

NLE Websites -- All DOE Office Websites (Extended Search)

A Standard Reference Frame for the Description A Standard Reference Frame for the Description of Nucleic Acid Base-pair Geometry Supplementary Material The report is available at Journal of Molecular Biology (2001) 313: 229 - 237 and The Nucleic Acid Cartesian coordinates for A, C, G, T, and U in the optimized reference frame Adenine, Cytosine, Guanine, Thymine, Uracil Standard chemical structures taken from Clowney et al. (1996), J. Am. Chem. Soc., 118, 509-518). These data do not include C1' atoms, which are placed here in the least-squares plane of the base atoms, with the purine C1'-N9 bond length and C1'-N9-C4 valence angle set respectively to 1.46 Å and 126.5° and the pyrimidine C1'-N1 bond and C1-N1-C2 angle to 1.47 Å and 118.1°. These distances and angles are based on the average glycosyl

15

Microsoft Word - tsukuba.final_5_26_00  

NLE Websites -- All DOE Office Websites (Extended Search)

Standard Reference Frame for the Description of Nucleic Acid Base-pair Geometry These preliminary recommendations were made at the Tsukuba Workshop on Nucleic Acid Structure and...

16

acid  

NLE Websites -- All DOE Office Websites (Extended Search)

Acid/Pueblo Canyon, New Mexico, Site. Acid/Pueblo Canyon, New Mexico, Site. This site is managed by the U.S. Department of Energy Office of Legacy Management. Site Description and History The Acid/Pueblo Canyon, New Mexico, Site is located near the town of Los Alamos, New Mexico, approximately 25 miles northwest of Santa Fe and 60 miles north-northeast of Albuquerque. The site is accessible from Canyon Road, which runs just south

17

Quantum Geometry and Interferometry  

E-Print Network (OSTI)

All existing experimental results are currently interpreted using classical geometry. However, there are theoretical reasons to suspect that at a deeper level, geometry emerges as an approximate macroscopic behavior of a quantum system at the Planck scale. If directions in emergent quantum geometry do not commute, new quantum-geometrical degrees of freedom can produce detectable macroscopic deviations from classicality: spatially coherent, transverse position indeterminacy between any pair of world lines, with a displacement amplitude much larger than the Planck length. Positions of separate bodies are entangled with each other, and undergo quantum-geometrical fluctuations that are not describable as metric fluctuations or gravitational waves. These fluctuations can either be cleanly identified or ruled out using interferometers. A Planck-precision test of the classical coherence of space-time on a laboratory scale is now underway at Fermilab.

Hogan, Craig

2012-01-01T23:59:59.000Z

18

Interactive geometry remeshing  

Science Conference Proceedings (OSTI)

We present a novel technique, both flexible and efficient, for interactive remeshing of irregular geometry. First, the original (arbitrary genus) mesh is substituted by a series of 2D maps in parameter space. Using these maps, our algorithm is then able ...

Pierre Alliez; Mark Meyer; Mathieu Desbrun

2002-07-01T23:59:59.000Z

19

Geometry-dependent lighting  

E-Print Network (OSTI)

Abstract In this paper we introduce geometrydependent lighting that allows lighting parameters to be defined independently and possibly discrepantly over an object or scene based on the local geometry. We present and discuss Light Collages, a lighting design system with geometry-dependent lights for effective feature-enhanced visualization. Our algorithm segments the objects into local surface patches and places lights that are locally consistent but globally discrepant to enhance the perception of shape. We use spherical harmonics for efficiently storing and computing light placement and assignment. We also outline a method to find the minimal number of light sources sufficient to illuminate an object well with our globally discrepant lighting approach. Index Terms Lighting design, scientific illustration, discrepant lighting, light placement, silhouette enhancement, proximity shadows, spherical harmonics I.

Chang Ha Lee; Xuejun Hao; Amitabh Varshney

2005-01-01T23:59:59.000Z

20

Covariant Macroscopic Quantum Geometry  

E-Print Network (OSTI)

A covariant noncommutative algebra of position operators is presented, and interpreted as the macroscopic limit of a geometry that describes a collective quantum behavior of the positions of massive bodies in a flat emergent space-time. The commutator defines a quantum-geometrical relationship between world lines that depends on their separation and relative velocity, but on no other property of the bodies, and leads to a transverse uncertainty of the geometrical wave function that increases with separation. The number of geometrical degrees of freedom in a space-time volume scales holographically, as the surface area in Planck units. Ongoing branching of the wave function causes fluctuations in transverse position, shared coherently among bodies with similar trajectories. The theory can be tested using appropriately configured Michelson interferometers.

Hogan, Craig J

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Indeterminacy of Quantum Geometry  

E-Print Network (OSTI)

An effective theory of quantum spacetime geometry based on wave optics is used to describe fundamental limits on propagation and measurement of information in holographic spacetimes. Wavefunctions describing spacetime event positions are modeled as complex disturbances of quasi-monochromatic Planck wavelength radiation. The transverse position on a two-dimensional geometrical wavefront, represented by the optical complex degree of coherence, is related to a prepared state represented by a transverse distribution of intensity on an initial wavefront. The transverse position distributions describing two macroscopically null-separated events are shown to approximate Fourier transforms of each other. This relationship is interpreted as an uncertainty inherent to spacetime: the product of standard deviations of transverse position of two events is equal to the product of their separation and the Planck length. For macroscopically separated events the uncertainty is much larger than the Planck length, and is predic...

Hogan, Craig J

2008-01-01T23:59:59.000Z

22

The Geometry of Homological Triangles  

E-Print Network (OSTI)

This book is addressed to students, professors and researchers of geometry, who will find herein many interesting and original results. The originality of the book The Geometry of Homological Triangles consists in using the homology of triangles as a "filter" through which remarkable notions and theorems from the geometry of the triangle are unitarily passed. Our research is structured in seven chapters, the first four are dedicated to the homology of the triangles, while the last ones to their applications.

Florentin Smarandache; Ion Patrascu

2012-04-07T23:59:59.000Z

23

The geometry of determinant line bundles in noncommutative geometry  

E-Print Network (OSTI)

This paper is concerned with the study of the geometry of determinant line bundles associated to families of spectral triples parametrized by the moduli space of gauge equivalent classes of Hermitian connections on a Hermitian finite projective module. We illustrate our results with some examples that arise in noncommutative geometry.

Chakraborty, Partha Sarathi

2008-01-01T23:59:59.000Z

24

The geometry of determinant line bundles in noncommutative geometry  

E-Print Network (OSTI)

This paper is concerned with the study of the geometry of determinant line bundles associated to families of spectral triples parametrized by the moduli space of gauge equivalent classes of Hermitian connections on a Hermitian finite projective module. We illustrate our results with some examples that arise in noncommutative geometry.

Partha Sarathi Chakraborty; Varghese Mathai

2008-04-21T23:59:59.000Z

25

Nucleic Acid Softwars  

NLE Websites -- All DOE Office Websites (Extended Search)

Nucleic Acid Software Nucleic Acid Software FR3D, a software for finding local and composite recurrent structural motifs in RNA 3D structures. Sarver, M., Zirbel, C.L., Stombaugh, J., Mokdad, A. and Leontis, N.B. (2008) FR3D: finding local and composite recurrent structural motifs in RNA 3D structures. J Math Biol, 56, 215-252. RNAView, a program for quickly generating a display of RNA/DNA secondary structures with tertiary interactions. Yang, H., Jossinet, F., Leontis, N., Chen, L., Westbrook, J., Berman, H.M. and Westhof, E. (2003) Tools for the automatic identification and classification of RNA base pairs. Nucleic Acids Res, 31, 3450-3460. RNAMLview, a program to display and/or edit RNAView 2-dimensional diagrams. 3DNA, a software package for the analysis, rebuilding and visualization of three-dimensional nucleic acid structures.

26

Dirk Windelberg NANO-GEOMETRY  

E-Print Network (OSTI)

Dirk Windelberg NANO-GEOMETRY detection of `unknown' pattern September 12th, 2008, Varna (Bulgaria Universit¨at Hannover #12;D.Windelberg: nano geometry marten4.tex (14. Januar 2010) 1 My lecture for solving the question: " was a given antique originally produced by van Gogh?" #12;D.Windelberg: nano

Windelberg, Dirk

27

Discovering role of linguistic geometry  

Science Conference Proceedings (OSTI)

Linguistic Geometry (LG) is a type of game theory for extensive discrete games scalable to the level of real life defense systems. LG was developed by generalizing experiences of the advanced chess players. In this paper we summarize experiences of highly ... Keywords: ancient warfare, artificial intelligence, game theory, linguistic geometry, search

Boris Stilman; Vladimir Yakhnis; Oleg Umanskiy

2010-11-01T23:59:59.000Z

28

Courant Algebroids in Parabolic Geometry  

E-Print Network (OSTI)

Let $p$ be a Lie subalgebra of a semisimple Lie algebra $g$ and $(G,P)$ be the corresponding pair of connected Lie groups. A Cartan geometry of type $(G,P)$ associates to a smooth manifold $M$ a principal $P$-bundle and a Cartan connection, and a parabolic geometry is a Cartan geometry where $P$ is parabolic. We show that if $P$ is parabolic, the adjoint tractor bundle of a Cartan geometry, which is isomorphic to the Atiyah algebroid of the principal $P$-bundle, admits the structure of a (pre-)Courant algebroid, and we identify the topological obstruction to the bracket being a Courant bracket. For semisimple $G$, the Atiyah algebroid of the principal $P$-bundle associated to the Cartan geometry of $(G,P)$ admits a pre-Courant algebroid structure if and only if $P$ is parabolic.

Stuart Armstrong; Rongmin Lu

2011-12-29T23:59:59.000Z

29

Quantum Geometry in the Lab  

E-Print Network (OSTI)

Standard particle theory is based on quantized matter embedded in a classical geometry. Here, a complementary model is proposed, based on classical matter -- massive bodies, without quantum properties -- embedded in a quantum geometry. It does not describe elementary particles, but may be a better, fully consistent quantum description for position states in laboratory-scale systems. Gravitational theory suggests that the geometrical quantum system has an information density of about one qubit per Planck length squared. If so, the model here predicts that the quantum uncertainty of geometry creates a new form of noise in the position of massive bodies, detectable by interferometers.

Craig Hogan

2013-03-24T23:59:59.000Z

30

Dirk Windelberg Nano-point-geometry  

E-Print Network (OSTI)

Dirk Windelberg Nano-point-geometry for use in material science 12. M¨arz 2010, M¨unchen D¨at Hannover #12;D.Windelberg: Nano-point-geometry for use in material science tr1003 e.tex (8. Juli 2010) 1 Nano-point-geometry for use in material science 1 microstructure 2 determination of height of voxels 3

Windelberg, Dirk

31

Quantum Geometry and Quantum Gravity  

E-Print Network (OSTI)

The purpose of this contribution is to give an introduction to quantum geometry and loop quantum gravity for a wide audience of both physicists and mathematicians. From a physical point of view the emphasis will be on conceptual issues concerning the relationship of the formalism with other more traditional approaches inspired in the treatment of the fundamental interactions in the standard model. Mathematically I will pay special attention to functional analytic issues, the construction of the relevant Hilbert spaces and the definition and properties of geometric operators: areas and volumes.

J. Fernando Barbero G.

2008-04-23T23:59:59.000Z

32

General Relativity and Weyl Geometry  

E-Print Network (OSTI)

We show that the general theory of relativity can be formulated in the language of Weyl geometry. We develop the concept of Weyl frames and point out that the new mathematical formalism may lead to different pictures of the same gravitational phenomena. We show that in an arbitrary Weyl frame general relativity, which takes the form of a scalar-tensor gravitational theory, is invariant with respect to Weyl tranformations. A kew point in the development of the formalism is to build an action that is manifestly invariant with respect to Weyl transformations. When this action is expressed in terms of Riemannian geometry we find that the theory has some similarities with Brans-Dicke gravitational theory. In this scenario, the gravitational field is not described by the metric tensor only, but by a combination of both the metric and a geometrical scalar field. We illustrate this point by, firstly, discussing the Newtonian limit in an arbitrary frame, and, secondly, by examining how distinct geometrical and physical pictures of the same phenomena may arise in different frames. To give an example, we discuss the gravitational spectral shift as viewed in a general Weyl frame. We further explore the analogy of general relativity with scalar-tensor theories and show how a known Brans-Dicke vacuum solution may appear as a solution of general relativity theory when reinterpreted in a particular Weyl frame. Finally, we show that the so-called WIST gravity theories are mathematically equivalent to Brans-Dicke theory when viewed in a particular frame.

C. Romero; J. B. Fonseca-Neto; M. L. Pucheu

2012-01-06T23:59:59.000Z

33

A Note on Real Tunneling Geometries  

E-Print Network (OSTI)

In the Hartle-Hawking ``no boundary'' approach to quantum cosmology, a real tunneling geometry is a configuration that represents a transition from a compact Riemannian spacetime to a Lorentzian universe. I complete an earlier proof that in three spacetime dimensions, such a transition is ``probable,'' in the sense that the required Riemannian geometry yields a genuine maximum of the semiclassical wave function.

S. Carlip

2005-08-17T23:59:59.000Z

34

Integral invariants for robust geometry processing  

Science Conference Proceedings (OSTI)

Differential invariants of curves and surfaces such as curvatures and their derivatives play a central role in Geometry Processing. They are, however, sensitive to noise and minor perturbations and do not exhibit the desired multi-scale behavior. Recently, ... Keywords: 3D shape understanding, Curvature, Geometry processing, Integral invariant, Stability

Helmut Pottmann; Johannes Wallner; Qi-Xing Huang; Yong-Liang Yang

2009-01-01T23:59:59.000Z

35

Velocity and processivity of helicase unwinding of double-stranded nucleic acids  

E-Print Network (OSTI)

Helicases are molecular motors which unwind double-stranded nucleic acids (dsNA) in cells. Many helicases move with directional bias on single-stranded (ss) nucleic acids, and couple their directional translocation to strand separation. A model of the coupling between translocation and unwinding uses an interaction potential to represent passive and active helicase mechanisms. A passive helicase must wait for thermal fluctuations to open dsNA base pairs before it can advance and inhibit NA closing. An active helicase directly destabilizes dsNA base pairs, accelerating the opening rate. Here we extend this model to include helicase unbinding from the nucleic-acid strand. The helicase processivity depends on the form of the interaction potential. A passive helicase has a mean attachment time which does not change between ss translocation and ds unwinding, while an active helicase in general shows a decrease in attachment time during unwinding relative to ss translocation. In addition, we describe how helicase u...

Betterton, M D; Julicher, Frank

2005-01-01T23:59:59.000Z

36

The Geometry of Jordan Matrix Models  

E-Print Network (OSTI)

We elucidate the geometry of matrix models based on simple formally real Jordan algebras. Such Jordan algebras give rise to a nonassociative geometry that is a generalization of Lorentzian geometry. We emphasize constructions for the exceptional Jordan algebra and the exceptional Jordan C*-algebra and describe the projective spaces related to the exceptional cubic matrix model and the E_6 matrix model. The resulting projective spaces are shown to be exceptional versions of projective twistor space, thus revealing the existence of exceptional twistor string theories that are dual to octonionic matrix models.

Michael Rios

2005-03-08T23:59:59.000Z

37

Iterated Differential Forms II: Riemannian Geometry Revisited  

E-Print Network (OSTI)

A natural extension of Riemannian geometry to a much wider context is presented on the basis of the iterated differential form formalism developed in math.DG/0605113 and an application to general relativity is given.

A. M. Vinogradov; L. Vitagliano

2006-09-11T23:59:59.000Z

38

Categorified Symplectic Geometry and the Classical String  

E-Print Network (OSTI)

and extended objects in string theory. http://arxiv.org/abs/Witten, E. : Anomalies in string theory with D-branes. AsianGeometry and the Classical String 26. Kalb, M. , Ramond,

Baez, John C.; Hoffnung, Alexander E.; Rogers, Christopher L.

2010-01-01T23:59:59.000Z

39

Emergence of wave equations from quantum geometry  

SciTech Connect

We argue that classical geometry should be viewed as a special limit of noncommutative geometry in which aspects which are inter-constrained decouple and appear arbitrary in the classical limit. In particular, the wave equation is really a partial derivative in a unified extra-dimensional noncommutative geometry and arises out of the greater rigidity of the noncommutative world not visible in the classical limit. We provide an introduction to this 'wave operator' approach to noncommutative geometry as recently used[27] to quantize any static spacetime metric admitting a spatial conformal Killing vector field, and in particular to construct the quantum Schwarzschild black hole. We also give an introduction to our related result that every classical Riemannian manifold is a shadow of a slightly noncommutative one wherein the meaning of the classical Ricci tensor becomes very natural as the square of a generalised braiding.

Majid, Shahn [School of Mathematical Sciences, Queen Mary University of London, 327 Mile End Rd, London E1 4NS (United Kingdom)

2012-09-24T23:59:59.000Z

40

Electromagnetic Casimir Forces in Elliptic Cylinder Geometries  

E-Print Network (OSTI)

The scattering theory approach makes it possible to carry out exact calculations of Casimir energies in any geometry for which the scattering T-matrix and a partial wave expansion of the free Green's function are available. We implement this program for the case of a perfectly conducting elliptic cylinder, thereby completing the set of geometries where electromagnetic scattering is separable. Particular emphasis is placed on the case of zero radius, where the elliptic cylinder reduces to a strip.

Noah Graham

2013-03-26T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Noncommutative geometry inspired wormholes with conformal motion  

E-Print Network (OSTI)

This paper discusses a new wormhole solution that admits conformal motion, given a noncommutative-geometry background. After a discussion of the wormhole geometry and the energy conditions, the analysis proceeds with the calculation of the active gravitational mass, a discussion of the TOV equation describing the equilibrium conditions, as well as the nature of the total gravitational energy. The wormhole spacetime is not asymptotically flat and is therefore cut off at some radial distance and joined to an exterior vacuum solution.

Farook Rahaman; Saibal Ray; G. S. Khadekar; P. K. F. Kuhfittig; Indrani Karar

2013-05-17T23:59:59.000Z

42

Bruhat-Tits buildings and analytic geometry  

E-Print Network (OSTI)

This paper provides an overview of the theory of Bruhat-Tits buildings. Besides, we explain how Bruhat-Tits buildings can be realized inside Berkovich spaces. In this way, Berkovich analytic geometry canbe used to compactify buildings. We discuss in detail the example of the special linear group. Moreover, we give an intrinsic description of Bruhat-Tits buildings in the framework of non-Archimedean analytic geometry.

Remy, Bertrand; Werner, Annette

2011-01-01T23:59:59.000Z

43

The geometry of sound rays in a wind  

E-Print Network (OSTI)

We survey the close relationship between sound and light rays and geometry. In the case where the medium is at rest, the geometry is the classical geometry of Riemann. In the case where the medium is moving, the more general geometry known as Finsler geometry is needed. We develop these geometries ab initio, with examples, and in particular show how sound rays in a stratified atmosphere with a wind can be mapped to a problem of circles and straight lines.

G. W. Gibbons; C. M. Warnick

2011-02-11T23:59:59.000Z

44

Engines - 3-D Animation Shows Complex Geometry of Diesel Particulates  

NLE Websites -- All DOE Office Websites (Extended Search)

3-D Animation Shows Complex Geometry of Diesel Particulates Diesel particulate matter has a very complex geometry Most studies have observed these three-dimensional structures in...

45

Build A Recreation Center Using Geometry Project  

NLE Websites -- All DOE Office Websites (Extended Search)

BUILD A RECREATION CENTER USING GEOMETRY BUILD A RECREATION CENTER USING GEOMETRY Project Description The city of West Chicago has recently acquired a small island on a nearby lake. The island is roughly circular with a radius of approximately two acres. Our geometry class is being asked to design a recreation center for the children of West Chicago. Our class has a very unique opportunity. Because of an anonymous donor, money is no object. The class will be divided into groups of approximately four students. The first task of each group is to decide which portion of the project your group will be responsible for designing. Below are your possible choices. Possible Topics Architecture Landscape Architecture Computer Games Bridges Art Other Finished Product Following is what your team is responsible for turning in at the end of the

46

Stippling and silhouettes rendering in geometry-image space  

Science Conference Proceedings (OSTI)

We present a novel non-photorealistic rendering method that performs all operations in a geometry-image domain. We first apply global conformal parameterization to the input geometry model and generate corresponding geometry images. Strokes and silhouettes ... Keywords: geometry image, non-photorealistic rendering, sampling, silhouette, stippling

Xiaoru Yuan; Minh X. Nguyen; Nan Zhang; Baoquan Chen

2005-06-01T23:59:59.000Z

47

Velocity and processivity of helicase unwinding of double-stranded nucleic acids  

E-Print Network (OSTI)

Helicases are molecular motors which unwind double-stranded nucleic acids (dsNA) in cells. Many helicases move with directional bias on single-stranded (ss) nucleic acids, and couple their directional translocation to strand separation. A model of the coupling between translocation and unwinding uses an interaction potential to represent passive and active helicase mechanisms. A passive helicase must wait for thermal fluctuations to open dsNA base pairs before it can advance and inhibit NA closing. An active helicase directly destabilizes dsNA base pairs, accelerating the opening rate. Here we extend this model to include helicase unbinding from the nucleic-acid strand. The helicase processivity depends on the form of the interaction potential. A passive helicase has a mean attachment time which does not change between ss translocation and ds unwinding, while an active helicase in general shows a decrease in attachment time during unwinding relative to ss translocation. In addition, we describe how helicase unwinding velocity and processivity vary if the base-pair binding free energy is changed.

M. D. Betterton; Frank Julicher

2005-09-15T23:59:59.000Z

48

D-branes and doubled geometry  

E-Print Network (OSTI)

We define the open string version of the nonlinear sigma model on doubled geometry introduced by Hull and Reid-Edwards, and derive its boundary conditions. These conditions include the restriction of D-branes to maximally isotropic submanifolds as well as a compatibility condition with the Lie algebra structure on the doubled space. We demonstrate a systematic method to derive and classify D-branes from the boundary conditions, in terms of embeddings both in the doubled geometry and in the physical target space. We apply it to the doubled three-torus with constant H-flux and find D0-, D1-, and D2-branes, which we verify transform consistently under T-dualities mapping the system to f-, Q- and R-flux backgrounds.

Cecilia Albertsson; Tetsuji Kimura; Ronald A. Reid-Edwards

2008-06-11T23:59:59.000Z

49

Generalized integrability conditions and target space geometry  

E-Print Network (OSTI)

In some higher dimensional nonlinear field theories integrable subsectors with infinitely many conservation laws have been identified by imposing additional integrability conditions. Originally, the complex eikonal equation was chosen as integrability condition, but recently further generalizations have been proposed. Here we show how these new integrability conditions may be derived from the geometry of the target space and, more precisely, from the Noether currents related to a certain class of target space transformations.

C. Adam; J. Sanchez-Guillen

2005-08-01T23:59:59.000Z

50

Intersecting solitons, amoeba, and tropical geometry  

Science Conference Proceedings (OSTI)

We study the generic intersection (or web) of vortices with instantons inside, which is a 1/4 Bogomol'nyi-Prasad-Sommerfield state in the Higgs phase of five-dimensional N=1 supersymmetric U(N{sub C}) gauge theory on R{sub t}x(C*){sup 2}{approx_equal}R{sup 2,1}xT{sup 2} with N{sub F}=N{sub C} Higgs scalars in the fundamental representation. In the case of the Abelian-Higgs model (N{sub F}=N{sub C}=1), the intersecting vortex sheets can be beautifully understood in a mathematical framework of amoeba and tropical geometry, and we propose a dictionary relating solitons and gauge theory to amoeba and tropical geometry. A projective shape of vortex sheets is described by the amoeba. Vortex charge density is uniformly distributed among vortex sheets, and negative contribution to instanton charge density is understood as the complex Monge-Ampere measure with respect to a plurisubharmonic function on (C*){sup 2}. The Wilson loops in T{sup 2} are related with derivatives of the Ronkin function. The general form of the Kaehler potential and the asymptotic metric of the moduli space of a vortex loop are obtained as a by-product. Our discussion works generally in non-Abelian gauge theories, which suggests a non-Abelian generalization of the amoeba and tropical geometry.

Fujimori, Toshiaki [Department of Physics, Tokyo Institute of Technology Tokyo 152-8551 (Japan); Nitta, Muneto [Department of Physics, Keio University, Hiyoshi, Yokohama, Kanagawa 223-8521 (Japan); Ohta, Kazutoshi [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Sakai, Norisuke [Department of Mathematics, Tokyo Woman's Christian University, Tokyo 167-8585 (Japan); Yamazaki, Masahito [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)

2008-11-15T23:59:59.000Z

51

Geometry of loop quantum gravity on a graph  

SciTech Connect

We discuss the meaning of geometrical constructions associated to loop quantum gravity states on a graph. In particular, we discuss the 'twisted geometries' and derive a simple relation between these and Regge geometries.

Rovelli, Carlo; Speziale, Simone [Centre de Physique Theorique, CNRS-Luminy Case 907, 13288 Marseille Cedex 09 (France)

2010-08-15T23:59:59.000Z

52

An Overview of Geometry Representation in Monte Carlo Codes  

National Nuclear Security Administration (NNSA)

Geometry Representation Geometry Representation in Monte Carlo Codes R.P. Kensek, * B.C. Franke, * T.W. Laub * , L.J. Lorence, * M. R. Martin, * S. Warren † * Sandia National Laboratories, P.O. Box 5800, MS 1179, Albuquerque, NM 87185 † Kansas State University, Manhattan, KS 66506 Geometry representations in production Monte Carlo radiation transport codes used for linear-transport simulations are traditionally limited to combinatorial geometry (CG) topologies. While CG representations of input geometries are efficient to query, they are difficult to construct. In the Integrated-TIGER-Series (ITS) Monte Carlo code suite, a new approach for radiation transport geometry engines has been implemented that allows for Computer Aided Design (CAD), facetted approximations, and other geometry types to simultaneously define an input geometry.

53

Notes on Differential Geometry and Lie Groups Jean Gallier  

E-Print Network (OSTI)

will be well prepared to read standard differential geometry texts such as do Carmo [51], Gallot, Hulin

Gallier, Jean

54

Notes on Differential Geometry and Lie Groups Jean Gallier  

E-Print Network (OSTI)

will be well prepared to read standard differential geometry texts such as do Carmo [50], Gallot, Hulin

Gallier, Jean

55

Standard Definitions of Building Geometry for Energy Evaluation  

SciTech Connect

This document provides definitions and metrics of building geometry for use in building energy evaluation. Building geometry is an important input in the analysis process, yet there are no agreed-upon standard definitions of these terms for use in energy analysis. The metrics can be used for characterizing building geometry, for calculating energy performance metrics, and for conducting energy simulations.

Deru, M.; Torcellini, P.

2005-10-01T23:59:59.000Z

56

Invariant geometry of the ideal gas  

E-Print Network (OSTI)

We analyze a Legendre invariant metric structure in the space of thermodynamic equilibrium states of an ideal gas. Due to the lack of thermodynamic interaction, the geometry turns out to be flat. We introduce the concept of thermodynamic geodesics, which correspond to quasi-static processes, analyze their properties, and show that they can be used to determine the "arrow of time" and to split the equilibrium space of the ideal gas into two completely different regions, separated by adiabatic geodesics which correspond to reversible thermodynamic processes.

Hernando Quevedo; Alberto Sanchez; Alejandro Vazquez

2008-11-03T23:59:59.000Z

57

Geodesic Reduction via Frame Bundle Geometry  

E-Print Network (OSTI)

A manifold with an arbitrary affine connection is considered and the geodesic spray associated with the connection is studied in the presence of a Lie group action. In particular, results are obtained that provide insight into the structure of the reduced dynamics associated with the given invariant affine connection. The geometry of the frame bundle of the given manifold is used to provide an intrinsic description of the geodesic spray. A fundamental relationship between the geodesic spray, the tangent lift and the vertical lift of the symmetric product is obtained, which provides a key to understanding reduction in this formulation.

Bhand, Ajit

2010-01-01T23:59:59.000Z

58

Stripe Instabilities of Geometries with Hyperscaling Violation  

E-Print Network (OSTI)

We study the dynamical stripe instabilities on the geometries with hyperscaling violation in the IR, which asymptotically approach AdS_4 in the UV. The instabilities break the translational invariance spontaneously and are induced by the axion term ~ a F \\wedge F in the bulk action. We first study the perturbation equations in the probe limit, and find that there is a strong correlation between the stripe instabilities caused by the axion term and parameters of the theories which determine the IR hyperscaling violation. Contrary to the IR AdS_2 case, the effect of the axion term for the stripe instabilities can be enhanced/suppressed at low temperature depending on the parameters. For a certain one-parameter family of the hyperscaling violation, we find the onset of the stripe instability analytically in the axion coupling tuned model. For more generic parameter range of hyperscaling violation, we study the instability onset by searching for the zero mode numerically on the full geometries. We also argue that quite analogous results hold, after taking into account the graviton fluctuation, i.e., beyond the probe limit.

Norihiro Iizuka; Kengo Maeda

2013-01-24T23:59:59.000Z

59

Surveying Diffusion in Complex Geometries. An Essay  

E-Print Network (OSTI)

The surrounding world surprises us by the beauty and variety of complex shapes that emerge from nanometric to macroscopic scales. Natural or manufactured materials (sandstones, sedimentary rocks and cement), colloidal solutions (proteins and DNA), biological cells, tissues and organs (lungs, kidneys and placenta), they all present irregularly shaped "scenes" for a fundamental transport "performance", that is, diffusion. Here, the geometrical complexity, entangled with the stochastic character of diffusive motion, results in numerous fascinating and sometimes unexpected effects like diffusion screening or localization. These effects control many diffusion-mediated processes that play an important role in heterogeneous catalysis, biochemical mechanisms, electrochemistry, growth phenomena, oil recovery, or building industry. In spite of a long and rich history of academic and industrial research in this field, it is striking to see how little we know about diffusion in complex geometries, especially the one which occurs in three dimensions. We present our recent results on restricted diffusion. We look into the role of geometrical complexity at different levels, from boundary microroughness to hierarchical structure and connectivity of the whole diffusion-confining domain. We develop a new approach which consists in combining fast random walk algorithms with spectral tools. The main focus is on studying diffusion in model complex geometries (von Koch boundaries, Kitaoka acinus, etc.), as well as on developing and testing spectral methods. We aim at extending this knowledge and at applying the accomplished arsenal of theoretical and numerical tools to structures found in nature and industry.

Denis Grebenkov

2009-09-08T23:59:59.000Z

60

Downstream hydraulic geometry relations: 1. Theoretical development  

E-Print Network (OSTI)

In this study, it is hypothesized that (1) the spatial variation of the stream power of a channel for a given discharge is accomplished by the spatial variation in channel form (flow depth and channel width) and hydraulic variables, including energy slope, flow velocity, and friction, and (2) that the change in stream power is distributed among the changes in flow depth, channel width, flow velocity, slope, and friction, depending on the constraints (boundary conditions) the channel has to satisfy. The second hypothesis is a result of the principles of maximum entropy and minimum energy dissipation or its simplified minimum stream power. These two hypotheses lead to four families of downstream hydraulic geometry relations. The conditions under which these families of relations can occur in field are discussed.

Singh, Vijay P.; Yang, Chih Ted; Deng, Z. Q.

2003-12-04T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Surveying Diffusion in Complex Geometries. An Essay  

E-Print Network (OSTI)

The surrounding world surprises us by the beauty and variety of complex shapes that emerge from nanometric to macroscopic scales. Natural or manufactured materials (sandstones, sedimentary rocks and cement), colloidal solutions (proteins and DNA), biological cells, tissues and organs (lungs, kidneys and placenta), they all present irregularly shaped "scenes" for a fundamental transport "performance", that is, diffusion. Here, the geometrical complexity, entangled with the stochastic character of diffusive motion, results in numerous fascinating and sometimes unexpected effects like diffusion screening or localization. These effects control many diffusion-mediated processes that play an important role in heterogeneous catalysis, biochemical mechanisms, electrochemistry, growth phenomena, oil recovery, or building industry. In spite of a long and rich history of academic and industrial research in this field, it is striking to see how little we know about diffusion in complex geometries, especially the one whic...

Grebenkov, Denis

2009-01-01T23:59:59.000Z

62

Acquisition of building geometry in the simulation of energy performance  

SciTech Connect

Building geometry is essential to any simulation of building performance. This paper examines the importing of building geometry into simulation of energy performance from the users' point of view. It lists performance requirements for graphic user interfaces that input building geometry, and discusses the basic options in moving from two- to three-dimensional definition of geometry and the ways to import that geometry into energy simulation. The obvious answer lies in software interoperability. With the BLIS group of interoperable software one can interactively import building geometry from CAD into EnergyPlus and dramatically reduce the effort otherwise needed for manual input.The resulting savings may greatly increase the value obtained from simulation, the number of projects in which energy performance simulation is used, and expedite decision making in the design process.

Bazjanac, Vladimir

2001-06-28T23:59:59.000Z

63

The Third Annual Video Review of Computational Geometry  

E-Print Network (OSTI)

Computational geometry concepts are often easiest to understand visually, in terms of the geometric objects they manipulate. Indeed, most papers in the field rely on diagrams to communicate the intuition behind their results. However, static figures are not always adequate. The accompanying videotape showcases advances in the use of algorithm animation, visualization, and interactive computing in the study of computational geometry. This report contains brief descriptions of all the segments of the videotape. This report is the third annual Video Review of Computational Geometry to be published as a SRC Research Report. The '92 Video Review is SRC Research Report 87, and the '93 Video Review is SRC Research Report 101. Future editions will be published by the ACM, as part of the proceedings of the annual ACM Symposium on Computational Geometry. Preface Computational geometry concepts are often easiest to understand visually. Indeed, most papers in computational geometry rely on diag...

Edited Marc; John Hershberger (eds.); Marc H. Brown; John Hershberger; Robert W. Taylor

1994-01-01T23:59:59.000Z

64

Transforming BIM to BEM: Generation of Building Geometry for...  

NLE Websites -- All DOE Office Websites (Extended Search)

Transforming BIM to BEM: Generation of Building Geometry for the NASA Ames Sustainability Base BIM NOTICE Due to the current lapse of federal funding, Berkeley Lab websites are...

65

Is there a Jordan geometry underlying quantum physics?  

E-Print Network (OSTI)

There have been several propositions for a geometric and essentially non-linear formulation of quantum mechanics. From a purely mathematical point of view, the point of view of Jordan algebra theory might give new strength to such approaches: there is a ``Jordan geometry'' belonging to the Jordan part of the algebra of observables, in the same way as Lie groups belong to the Lie part. Both the Lie geometry and the Jordan geometry are well-adapted to describe certain features of quantum theory. We concentrate here on the mathematical description of the Jordan geometry and raise some questions concerning possible relations with foundational issues of quantum theory.

Wolfgang Bertram

2008-01-20T23:59:59.000Z

66

Rheological control on the initial geometry of the Raft River...  

Open Energy Info (EERE)

Rheological control on the initial geometry of the Raft River detachment fault and shear zone, western United States Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home...

67

Information Geometry and Primal-Dual Interior-point Algorithms  

E-Print Network (OSTI)

May 14, 2010 ... Abstract: In this paper, we study polynomial-time interior-point algorithms in view of information geometry. We introduce an information...

68

Information Geometry and Interior-Point Algorithms in SDP and ...  

E-Print Network (OSTI)

Sep 30, 2011 ... admits a rigorous differential geometric expression in view of information geometry. Our result is a direct extension of [10] in linear programming...

69

Scientist Finds Nature and Geometry Dancing to the Same Tune...  

Office of Science (SC) Website

Scientist Finds Nature and Geometry Dancing to the Same Tune News Featured Articles 2013 2012 2011 2010 2009 2008 2007 2006 2005 Science Headlines Presentations & Testimony News...

70

Interferometers as Probes of Planckian Quantum Geometry  

E-Print Network (OSTI)

A theory of position of massive bodies is proposed that results in an observable quantum behavior of geometry at the Planck scale, $t_P$. Departures from classical world lines in flat spacetime are described by Planckian noncommuting operators for position in different directions, as defined by interactions with null waves. The resulting evolution of position wavefunctions in two dimensions displays a new kind of directionally-coherent quantum noise of transverse position. The amplitude of the effect in physical units is predicted with no parameters, by equating the number of degrees of freedom of position wavefunctions on a 2D spacelike surface with the entropy density of a black hole event horizon of the same area. In a region of size $L$, the effect resembles spatially and directionally coherent random transverse shear deformations on timescale $\\approx L/c$ with typical amplitude $\\approx \\sqrt{ct_PL}$. This quantum-geometrical "holographic noise" in position is not describable as fluctuations of a quantized metric, or as any kind of fluctuation, dispersion or propagation effect in quantum fields. In a Michelson interferometer the effect appears as noise that resembles a random Planckian walk of the beamsplitter for durations up to the light crossing time. Signal spectra and correlation functions in interferometers are derived, and predicted to be comparable with the sensitivities of current and planned experiments. It is proposed that nearly co-located Michelson interferometers of laboratory scale, cross-correlated at high frequency, can test the Planckian noise prediction with current technology.

Craig J. Hogan

2010-02-25T23:59:59.000Z

71

Measurement of Quantum Fluctuations in Geometry  

E-Print Network (OSTI)

A particular form for the quantum indeterminacy of relative spacetime position of events is derived from the limits of measurement possible with Planck wavelength radiation. The indeterminacy predicts fluctuations from a classically defined geometry in the form of ``holographic noise'' whose spatial character, absolute normalization, and spectrum are predicted with no parameters. The noise has a distinctive transverse spatial shear signature, and a flat power spectral density given by the Planck time. An interferometer signal displays noise due to the uncertainty of relative positions of reflection events. The noise corresponds to an accumulation of phase offset with time that mimics a random walk of those optical elements that change the orientation of a wavefront. It only appears in measurements that compare transverse positions, and does not appear at all in purely radial position measurements. A lower bound on holographic noise follows from a covariant upper bound on gravitational entropy. The predicted holographic noise spectrum is estimated to be comparable to measured noise in the currently operating interferometer GEO600. Because of its transverse character, holographic noise is reduced relative to gravitational wave effects in other interferometer designs, such as LIGO, where beam power is much less in the beamsplitter than in the arms.

Craig J. Hogan

2007-12-20T23:59:59.000Z

72

Applications of Poisson Geometry to Physical Problems  

E-Print Network (OSTI)

We consider Lagrangians in Hamilton's principle defined on the tangent space $TG$ of a Lie group $G$. Invariance of such a Lagrangian under the action of $G$ leads to the symmetry-reduced Euler-Lagrange equations called the Euler-Poincar\\'e equations. In this case, the invariant Lagrangian is defined on the Lie algebra of the group and its Euler-Poincar\\'e equations are defined on the dual Lie algebra, where dual is defined by the operation of taking variational derivative. On the Hamiltonian side, the Euler-Poincar\\'e equations are Lie-Poisson and they possess accompanying momentum maps, which encode both their conservation laws and the geometry of their solution space. The standard Euler-Poincar\\'e examples are treated, including particle dynamics, the rigid body, the heavy top and geodesic motion on Lie groups. Additional topics deal with Fermat's principle, the $\\mathbb{R}^3$ Poisson bracket, polarized optical traveling waves, deformable bodies (Riemann ellipsoids) and shallow water waves, including the i...

Holm, Darryl D

2007-01-01T23:59:59.000Z

73

GRworkbench: A Computational System Based on Differential Geometry  

E-Print Network (OSTI)

We have developed a new tool for numerical work in General Relativity: GRworkbench. While past tools have been ad hoc, GRworkbench closely follows the framework of Differential Geometry to provide a robust and general way of computing on analytically defined space-times. We discuss the relationship between Differential Geometry and C++ classes in GRworkbench, and demonstrate their utility.

Susan M Scott; Benjamin J K Evans; Antony C Searle

2001-11-19T23:59:59.000Z

74

Vectorising the detector geometry to optimize particle transport  

E-Print Network (OSTI)

Among the components contributing to particle transport, geometry navigation is an important consumer of CPU cycles. The tasks performed to get answers to "basic" queries such as locating a point within a geometry hierarchy or computing accurately the distance to the next boundary can become very computing intensive for complex detector setups. So far, the existing geometry algorithms employ mainly scalar optimisation strategies (voxelization, caching) to reduce their CPU consumption. In this paper, we would like to take a different approach and investigate how geometry navigation can benefit from the vector instruction set extensions that are one of the primary source of performance enhancements on current and future hardware. While on paper, this form of microparallelism promises increasing performance opportunities, applying this technology to the highly hierarchical and multiply branched geometry code is a difficult challenge. We refer to the current work done to vectorise an important part of the critical navigation algorithms in the ROOT geometry library. Starting from a short critical discussion about the programming model, we present the current status and first benchmark results of the vectorisation of some elementary geometry shape algorithms. On the path towards a full vector-based geometry navigator, we also investigate the performance benefits in connecting these elementary functions together to develop algorithms which are entirely based on the flow of vector-data. To this end, we discuss core components of a simple vector navigator that is tested and evaluated on a toy detector setup.

John Apostolakis; Ren Brun; Federico Carminati; Andrei Gheata; Sandro Wenzel

2013-12-03T23:59:59.000Z

75

Friedmann Thermodynamics and the Geometry of the Universe  

E-Print Network (OSTI)

In a recent article we have introduced Friedmann thermodynamics, where certain geometric parameters in Friedmann models are treated like their thermodynamic counterparts (temperature, entropy, Gibbs potential etc.). This model has the advantage of allowing us to determine the geometry of the universe by thermodynamic stability arguments. In this article we review connections between thermodynamics, geometry and cosmology.

Bayin, Selcuk S

2008-01-01T23:59:59.000Z

76

Friedmann Thermodynamics and the Geometry of the Universe  

E-Print Network (OSTI)

In a recent article we have introduced Friedmann thermodynamics, where certain geometric parameters in Friedmann models are treated like their thermodynamic counterparts (temperature, entropy, Gibbs potential etc.). This model has the advantage of allowing us to determine the geometry of the universe by thermodynamic stability arguments. In this article we review connections between thermodynamics, geometry and cosmology.

Selcuk S. Bayin

2008-04-01T23:59:59.000Z

77

NA Standards | Valence Geometries | Table 1 Ref.  

NLE Websites -- All DOE Office Websites (Extended Search)

1: References for Mononucleoside and Mononucleotide Structures 1: References for Mononucleoside and Mononucleotide Structures used in Anke Gelbin, Bohdan Schneider, Lester Clowney, Shu-Hsin Hsieh, Wilma K. Olson, and Helen M. Berman. "Geometric Parameters in Nucleic Acids: Sugar and Phosphate Constituents. (1996) J. Am. Chem. Soc. 118, 519-529. -------------------------------------------------------------------------- CSD ID Compound Reference -------------------------------------------------------------------------- fikhai 3',5'-Di-O-acetyl-2'-deoxyadenosine Koole, L. H., et al. Can. J. Chem., 1987, 65, 326 fikhai01 3',5'-Di-O-acetyl-2'-deoxyadenosine Low, J. N., et al. Acta Cryst., 1988, C44, 2202 foylua 3'-O-acetyl-2'-deoxyadenosine Low, J. N., et al.

78

Argonne TTRDC - Engines - Multi-Dimensional Modeling - Orifice Geometry  

NLE Websites -- All DOE Office Websites (Extended Search)

Multi-Dimensional Modeling: Multi-Dimensional Modeling: Effect of Nozzle Orifice Geometry fuel vapor volume fractions Fig 1. Fuel vapor volume fractions for the three nozzles Nozzle orifice geometry is known to influence the flow inside the nozzle, which in turn affects the spray development, thus impacting combustion and emission processes. In the past, modeling studies have focused on the influence of nozzle orifice geometry on the flow inside the orifice only. This is mainly due to the lack of a suitable primary breakup model. Argonne engineers, with the help of the KH-ACT model, investigated the influence of nozzle orifice geometry not only on nozzle flow, but on spray, combustion and emission characteristics. Three different nozzle geometries were investigated (Fig. 1): Cylindrical (K=0, r/R=0)

79

Optimal tiling for the RNA base pairing problem  

Science Conference Proceedings (OSTI)

Dynamic programming is an important combinatorial optimization technique that has been widely used in various fields such as control theory, operations research, computational biology and computer science. Many authors have described parallel dynamic ... Keywords: BSP model, MPI, RNA secondary structure prediction, SPMD, dynamic programming, granularity on distributed memory machines, loop partitioning

Francisco Almeida; Rumen Andonov; Daniel Gonzalez; Luz M. Moreno; Vincent Poirriez; Casiano Rodriguez

2002-08-01T23:59:59.000Z

80

Density-functional theory study of gramicidin A ion channel geometry and electronic properties  

E-Print Network (OSTI)

Understanding the mechanisms underlying ion channel function from the atomic-scale requires accurate ab initio modelling as well as careful experiments. Here, we present a density functional theory (DFT) study of the ion channel gramicidin A, whose inner pore conducts only monovalent cations and whose conductance has been shown to depend on the side chains of the amino acids in the channel. We investigate the ground-state geometry and electronic properties of the channel in vacuum, focusing on their dependence on the side chains of the amino acids. We find that the side chains affect the ground state geometry, while the electrostatic potential of the pore is independent of the side chains. This study is also in preparation for a full, linear scaling DFT study of gramicidin A in a lipid bilayer with surrounding water. We demonstrate that linear scaling DFT methods can accurately model the system with reasonable computational cost. Linear scaling DFT allows ab initio calculations with 10,000 to 100,000 atoms an...

Todorovi?, Milica; Gillan, M J; Miyazaki, Tsuyoshi

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Alternative IR geometries for TESLA with a small crossing angle  

E-Print Network (OSTI)

The formulation of hybrid crossing angle schemes has been a recent development of the TESLA collision geometry debate. Here we report on two such schemes, characterised by either a small vertical or horizontal beam crossing angle.

R. Appleby; D. Angal-Kalinin; P. Bambade; B. Mouton; O. Napoly; J. Payet; the TESLA Collaboration

2004-12-09T23:59:59.000Z

82

Thermal techniques for characterizing magma body geometries | Open Energy  

Open Energy Info (EERE)

techniques for characterizing magma body geometries techniques for characterizing magma body geometries Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Thermal techniques for characterizing magma body geometries Details Activities (1) Areas (1) Regions (0) Abstract: The surface heat flux distribution resulting from emplaced magma bodies can be used to help characterize the magma source. Closed-form analytical solutions for the conduction heat transfer from various idealized magma geometries (dikes, sills, and spheres) are obtained using either the Schwarz-Christoffel transformation theorem (dikes and sills) or the 'method of images' with superposition (spheres). Comparison of these analytically determined heat flux distributions with field data from active geothermal areas at Yellowstone, Avachinsky volcano, Kilauea Iki,

83

Radiative Transfer in Cloud Fields with Random Geometry  

Science Conference Proceedings (OSTI)

Numerical results are given to estimate the importance of effects associated with the stochastic geometry of cloud fields. These results show the important of treating radiative transfer in broken clouds as a statistical problem. In the case of ...

Vladimir E. Zuev; Georgii A. Titov

1995-01-01T23:59:59.000Z

84

Layer-by-layer assembly in confined geometries  

E-Print Network (OSTI)

The fundamental nature of layer-by-layer (LbL) assembly in confined geometries was investigated for a number of different chemical systems. The first part of this thesis concerns the modification of microfluidic and ...

DeRocher, Jonathan P

2011-01-01T23:59:59.000Z

85

MISR-Derived Statistics of Cumulus Geometry at TWP Site  

NLE Websites -- All DOE Office Websites (Extended Search)

statistics of the cumulus geometry are presented in Figure 5a and Table 1a. There is a weak positive relationship between fluctuations of cloud base and cloud top (correlation...

86

Diffraction of Continental Shelf Waves by Irregular Alongshore Geometry  

Science Conference Proceedings (OSTI)

Diffraction of continental shelf waves by irregular alongshore geometry, such as ridges, canyons and bumps, is examined. The full barotropic, shelf-wave equation is treated, and the solutions include forward and back scattering, and a description ...

Dong-Ping Wang

1980-08-01T23:59:59.000Z

87

Hexagonal-geometry fast-reactor nodal modeling  

Science Conference Proceedings (OSTI)

Several nodal methods have been developed for simulating power distributions in thermal reactors, and have been tested for applicability to fast reactor problems. The testing was performed in rectangular geometry. Since fast reactor configurations typically use hexagonal assemblies, the most promising of the techniques tested was extended to hexagonal geometry and applied to a range of test cases. The approach selected was the generalized coarse mesh procedure (GCMDT) using different interpolation parameters in different zones.

Caro, E.; Becker, M.

1982-01-01T23:59:59.000Z

88

Triangle geometry processing for surface modeling and cartesian grid generation  

DOE Patents (OSTI)

Cartesian mesh generation is accomplished for component based geometries, by intersecting components subject to mesh generation to extract wetted surfaces with a geometry engine using adaptive precision arithmetic in a system which automatically breaks ties with respect to geometric degeneracies. During volume mesh generation, intersected surface triangulations are received to enable mesh generation with cell division of an initially coarse grid. The hexagonal cells are resolved, preserving the ability to directionally divide cells which are locally well aligned.

Aftosmis, Michael J. (San Mateo, CA); Melton, John E. (Hollister, CA); Berger, Marsha J. (New York, NY)

2002-09-03T23:59:59.000Z

89

Heat Transfer Limitations in Hydrogen Production Via Steam Reformation: The Effect of Reactor Geometry  

E-Print Network (OSTI)

Hydrogen production Reactors, M.S. Thesis, University ofREFORMATION: THE EFFECT OF REACTOR GEOMETRY David, R. ,have been manifest with reactors of different geometries. In

Vernon, David R.; Davieau, David D.; Dudgeon, Bryce A.; Erickson, Paul A.

2006-01-01T23:59:59.000Z

90

Physics of relativistic electron beams in rectangular and cylindrical geometries  

SciTech Connect

The use of electron beams for the direct pumping of lasers for fusion applications requires the generation of large area beams in appropriate geometries. Two geometries which are of particular interest are rectangular electron beams with planar anodes and radially converging beams with cyclindrical anodes. The generation of such beams requires the management of electron trajectories in a complex combination of applied and self-generated electric and magnetic fields. The beam's self-electric field limits the emitted current and the deflection of the electron in the self-magnetic field (beam pinch) limits the beam area that can be generated from a single cathode. A simple analytic model is used to derive a scaling relationship for beam pinch in both geometries of the form V/sup 1/2/ w/d = $alpha$ where V is the diode voltage, w the beam width, d the anode-cathode spacing, and $alpha$ is a weak function of the geometry. Numerical calculations are presented to show the effects of nonuniform electric fields encountered in typical geometries together with supporting experimental measurements. (auth)

Schlitt, L.G.; Bradley, L.P.

1975-11-01T23:59:59.000Z

91

Geometry of Cenozoic extensional faulting: Dixie Valley, Nevada | Open  

Open Energy Info (EERE)

Geometry of Cenozoic extensional faulting: Dixie Valley, Nevada Geometry of Cenozoic extensional faulting: Dixie Valley, Nevada Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Geometry of Cenozoic extensional faulting: Dixie Valley, Nevada Abstract Precise definition of geometric relationships between individual basins and ranges may help to reveal the mechanical processes of Basin and Range Cenozoic extensional faulting at depth. Previous studies have attempted to identify simple horsts and grabens, tilted crustal blocks with planar faulting, or tilted crustal blocks with listric faulting in the shallow crust. Normal faults defining these crustal blocks may root (1) individually in the ductile lower crust, (2) in regional or local low-angle detachment faults, or (3) in igneous intrusions or decoupling surfaces

92

Evaluation of subsurface fracture geometry using fluid pressure response to  

Open Energy Info (EERE)

subsurface fracture geometry using fluid pressure response to subsurface fracture geometry using fluid pressure response to solid earth tidal strain Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Evaluation of subsurface fracture geometry using fluid pressure response to solid earth tidal strain Details Activities (1) Areas (1) Regions (0) Abstract: The nature of solid earth tidal strain and surface load deformation due to the influence of gravitational forces and barometric pressure loading are discussed. The pore pressure response to these types of deformation is investigated in detail, including the cases of a confined aquifer intersected by a well and a discrete fracture intersected by a well. The integration of the tidal response method with conventional pump tests in order to independently calculate the hydraulic parameters of the

93

Thermodynamic geometry of charged rotating BTZ black holes  

SciTech Connect

We study the thermodynamics and the thermodynamic geometries of charged rotating Banados-Teitelboim-Zanelli black holes in (2+1)-gravity. We investigate the thermodynamics of these systems within the context of the Weinhold and Ruppeiner thermodynamic geometries and the recently developed formalism of geometrothermodynamics. Considering the behavior of the heat capacity and the Hawking temperature, we show that Weinhold and Ruppeiner geometries cannot describe completely the thermodynamics of these black holes and of their limiting case of vanishing electric charge. In contrast, the Legendre invariance imposed on the metric in geometrothermodynamics allows one to describe the charged rotating Banados-Teitelboim-Zanelli black holes and their limiting cases in a consistent and invariant manner.

Akbar, M. [Center for Advanced Mathematics and Physics, National University of Sciences and Technology, H-12, Islamabad (Pakistan); Quevedo, H. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, AP 70543, Mexico, DF 04510 (Mexico); ICRANet, Dipartimento di Fisica, Universita di Roma La Sapienza, I-00185 Roma (Italy); Saifullah, K. [Department of Mathematics, Quaid-i-Azam University, Islamabad (Pakistan); Sanchez, A. [Departamento de Posgrado, CIIDET, AP 752, Queretaro, QRO 76000 (Mexico); Taj, S. [Center for Advanced Mathematics and Physics, National University of Sciences and Technology, H-12, Islamabad (Pakistan); ICRANet, Dipartimento di Fisica, Universita di Roma La Sapienza, I-00185 Roma (Italy)

2011-04-15T23:59:59.000Z

94

Current Correlators and AdS/CFT Geometry  

E-Print Network (OSTI)

We consider current-current correlators in 4d $\\N =1$ SCFTs, and also 3d $\\N =2$ SCFTs, in connection with AdS/CFT geometry. The superconformal $U(1)_R$ symmetry of the SCFT has the distinguishing property that, among all possibilities, it minimizes the coefficient, $\\tau_{RR}$ of its two-point function. We show that the geometric Z-minimization condition of Martelli, Sparks, and Yau precisely implements $\\tau_{RR}$ minimization. This gives a physical proof that Z-minimization in geometry indeed correctly determines the superconformal R-charges of the field theory dual. We further discuss and compare current two point functions in field theory and AdS/CFT and the geometry of Sasaki-Einstein manifolds. Our analysis gives new quantitative checks of the AdS/CFT correspondence.

Edwin Barnes; Elie Gorbatov; Ken Intriligator; Jason Wright

2005-07-14T23:59:59.000Z

95

Interferente ntre Mecanica si Geometrie Constantin P. Niculescu  

E-Print Network (OSTI)

Interferen¸te între Mecanic¼a ¸si Geometrie Constantin P. Niculescu Utilizarea ideilor din Mecanic¼a¸tinând interpret¼ari în Mecanic¼a ale diferitelor enun¸turi din Geometrie ¸si invers. Bineîn¸teles, Gazeta, începând cu reintroducerea no¸tiunilor matematice legate de Mecanic¼a (vitez¼a, accelera¸tie, vector, func

Niculescu, Constantin P.

96

Novel geometry gradient coils for MRI designed by genetic algorithm  

E-Print Network (OSTI)

and the irradiating El field from the probe when the latter is used as a transmitter. 12 This is maximal when the field profile of the coil is perpendicular to the main field direction. Hence we want to choose a probe geometry which produces fields perpendicular... to Bo. These probe field are conventionally called El fields. Since we ideally require constant contrast, uniformity is also required across the sample. Probe geometry There are several standard designs of rJ. probes which are used within magnetic...

Williams, Guy Barnett

2001-06-19T23:59:59.000Z

97

On the isothermal geometry of corrugated graphene sheets  

E-Print Network (OSTI)

Variational geometries describing corrugated graphene sheets are proposed. The isothermal material properties of these sheets are described by a 2-dimensional Weyl space. The equation that couples the Weyl geometry with isothermal distributions of the temperature of graphene sheets, is formulated. This material space is observed in a 3-dimensional orthogonal configurational point space as regular surfaces which are endowed with a thermal state vector field fulfilling the isothermal thermal state equation. It enables to introduce a non-topological dimensionless thermal shape parameter of non-developable graphene sheets. The properties of the congruence of lines generated by the thermal state vector field are discussed.

Andrzej Trzesowski

2013-12-17T23:59:59.000Z

98

Geometry of Interaction V: Logic in the hyperfinite factor  

Science Conference Proceedings (OSTI)

Geometry of Interaction is a transcendental syntax developed in the framework of operator algebras. This fifth installment of the program takes place inside a von Neumann algebra, the hyperfinite factor. It provides a built-in interpretation of cut-elimination ... Keywords: Complexity theory, Light logics, Linear logic, Operator algebras, Proof-theory

Jean-Yves Girard

2011-04-01T23:59:59.000Z

99

Adhesion and the Geometry of the Cosmic Web  

E-Print Network (OSTI)

We present a new way to formulate the geometry of the Cosmic Web in terms of Lagrangian space. The Adhesion model has an ingenious geometric interpretation out of which the spine of the Cosmic Web emerges naturally. Within this context we demonstrate a deep connection of the relation between Eulerian and Lagrangian space with that between Voronoi and Delaunay tessellations.

Johan Hidding; Rien van de Weygaert; Gert Vegter; Bernard J. T. Jones

2012-11-22T23:59:59.000Z

100

From string theory to algebraic geometry and back  

Science Conference Proceedings (OSTI)

We describe some facts in physics which go up to the modern string theory and the related concepts in algebraic geometry. Then we present some recent results on moduli-spaces of vector bundles on non-Kaehler Calabi-Yau 3-folds and their consequences for heterotic string theory.

Brinzanescu, Vasile ['Simion Stoilow' Institute of Mathematics of the Romanian Academy, P.O.Box 1-764, Bucharest (Romania)

2011-02-10T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

PARABOLIC GEODESICS AS PARALLEL CURVES IN PARABOLIC GEOMETRIES  

E-Print Network (OSTI)

PARABOLIC GEODESICS AS PARALLEL CURVES IN PARABOLIC GEOMETRIES MARC HERZLICH Abstract. We give a simple characterization of the parabolic geodesics introduced by Cap, Slovák and Zádník for all parabolic then show that parabolic geodesics can be characterized as the following data: a curve on the manifold

Paris-Sud XI, Université de

102

String-Like Lagrangians from a Generalized Geometry  

E-Print Network (OSTI)

This note will use Hitchin's generalized geometry and a model of axionic gravity developed by Warren Siegel in the mid-nineties to show that the construction of Lagrangians based on the inner product arising from the pairing of a vector and its dual can lead naturally to the low-energy Lagrangian of the bosonic string.

Stephen Morris

2007-10-03T23:59:59.000Z

103

Greyscale Photograph Geometry Informed by Dodging and Burning  

E-Print Network (OSTI)

Greyscale Photograph Geometry Informed by Dodging and Burning Carlos Phillips and Kaleem Siddiqi the same negative may vary in inten- sity values due, in part, to the liberal use of dodging and burning to linear dodging and burning. 1 Introduction Photographs are often used as test data in the computer vision

Siddiqi, Kaleem

104

Decay Rates for Spherical Scalar Waves in the Schwarzschild Geometry  

E-Print Network (OSTI)

The Cauchy problem is considered for the scalar wave equation in the Schwarzschild geometry. Using an integral spectral representation we derive the exact decay rate for solutions of the Cauchy problem with spherical symmetric initial data, which is smooth and compactly supported outside the event horizon.

Johann Kronthaler

2007-09-24T23:59:59.000Z

105

Volumetric Geometry Reconstruction of Turbine Blades for Aircraft Engines  

E-Print Network (OSTI)

Volumetric Geometry Reconstruction of Turbine Blades for Aircraft Engines David Gro?mann1 and Bert-spline parametrization of turbine blades from measurement data generated by optical scanners. This new representation elements. We focus on the industrial applicability of the framework, by using standard turbine blade

Jüttler, Bert

106

Effective fracture geometry obtained with large water sand ratio  

E-Print Network (OSTI)

Shale gas formation exhibits some unusual reservoir characteristics: nano-darcy matrix permeability, presence of natural fractures and gas storage on the matrix surface that makes it unique in many ways. Its difficult to design an optimum fracture treatment for such formation and even more difficult is to describe production behavior using a reservoir model. So far homogeneous, two wing fracture, and natural fracture models have been used for this purpose without much success. Micro seismic mapping technique is used to measure the fracture propagation in real time. This measurement in naturally fractured shale formation suggests a growth of fracture network instead of a traditional two wing fractures. There is an industry wise consensus that fracture network plays an important role in determining the well productivity of such formations. A well with high density of fracture networks supposed to have better productivity. Shale formations have also exhibited production pattern which is very different from conventional or tight gas reservoir. Initial flow period is marked by steep decline in production while the late time production exhibits a slow decline. One of the arguments put for this behavior is linear flow from a bi-wing fractured well at early time and contribution of adsorbed gas in production at late time. However, bi-wing fracture geometry is not supported by the micro-seismic observation. A realistic model should include both the fracture network and adsorbed gas property. In this research we have proposed a new Power Law Permability model to simulate fluid flow from hydraulically fractured Shale formation. This model was first described by Valko & Fnu (2002) and used for analyzing acid treatment jobs. The key idea of this model is to use a power law permeability function that varies with the radial distance from well bore. Scaling exponent of this power law function has been named power law index. The permeability function has also been termed as secondary permeability. This work introduces the method of Laplace solution to solve the problem of transient and pseudo steady-state flow in a fracture network. Development and validation of this method and its extension to predict the pressure (and production) behaviour of fracture network were made using a novel technic. Pressure solution was then combined with material balance through productivity index to make production forecast. Reservoir rock volume affected by the fracture stimulation treatment that contributes in the production is called effective stimulated volume. This represents the extent of fracture network in this case. Barnett shale formation is a naturally fractured shale reservoir in Fort Worth basin. Several production wells from this formation was analysed using Power Law Model and it was found that wells productivity are highly dependent on stimulated volume. Apparently the wells flow under pseudo steady state for most part of their producing life and the effect of boundary on production is evident in as soon as one months of production. Due to short period of transient flow production from Barnett formations is expected to be largely independent of the relative distribution of permeability and highly dependent on the stimulated area and induced secondary permeability. However, an indirect relationship between permeability distribution and production rate is observed. A well with low power law index shows a better (more even) secondary permeability distribution in spatial direction, larger stimulated volume and better production. A comparative analysis between the new model and traditional fracture model was made. It was found that both models can be used successfully for history matching and production forecasting from hydraulically fractured shale gas formation.

Kumar, Amrendra

2008-12-01T23:59:59.000Z

107

Investigation of Created Fracture Geometry through Hydraulic Fracture Treatment Analysis  

E-Print Network (OSTI)

Successful development of shale gas reservoirs is highly dependent on hydraulic fracture treatments. Many questions remain in regards to the geometry of the created fractures. Production data analysis from some shale gas wells quantifies a much smaller stimulated pore volume than what would be expected from microseismic evidence and reports of fracturing fluids reaching distant wells. In addition, claims that hydraulic fracturing may open or reopen a network of natural fractures is of particular interest. This study examines hydraulic fracturing of shale gas formations with specific interest in fracture geometry. Several field cases are analyzed using microseismic analysis as well as net pressure analysis of the fracture treatment. Fracture half lengths implied by microseismic events for some of the stages are several thousand feet in length. The resulting dimensions from microseismic analysis are used for calibration of the treatment model. The fracture profile showing created and propped fracture geometry illustrates that it is not possible to reach the full fracture geometry implied by microseismic given the finite amount of fluid and proppant that was pumped. The model does show however that the created geometry appears to be much larger than half the well spacing. From a productivity standpoint, the fracture will not drain a volume more than that contained in half of the well spacing. This suggests that for the case of closely spaced wells, the treatment size should be reduced to a maximum of half the well spacing. This study will provide a framework for understanding hydraulic fracture treatments in shale formations. In addition, the results from this study can be used to optimize hydraulic fracture treatment design. Excessively large treatments may represent a less than optimal approach for developing these resources.

Ahmed, Ibraheem 1987-

2012-12-01T23:59:59.000Z

108

Method for high-volume sequencing of nucleic acids: random and directed priming with libraries of oligonucleotides  

DOE Patents (OSTI)

Random and directed priming methods for determining nucleotide sequences by enzymatic sequencing techniques, using libraries of primers of lengths 8, 9 or 10 bases, are disclosed. These methods permit direct sequencing of nucleic acids as large as 45,000 base pairs or larger without the necessity for subcloning. Individual primers are used repeatedly to prime sequence reactions in many different nucleic acid molecules. Libraries containing as few as 10,000 octamers, 14,200 nonamers, or 44,000 decamers would have the capacity to determine the sequence of almost any cosmid DNA. Random priming with a fixed set of primers from a smaller library can also be used to initiate the sequencing of individual nucleic acid molecules, with the sequence being completed by directed priming with primers from the library. In contrast to random cloning techniques, a combined random and directed priming strategy is far more efficient. 2 figs.

Studier, F.W.

1995-04-18T23:59:59.000Z

109

Mudrov Twist-related geometries on q-Minkowski space  

E-Print Network (OSTI)

The role of the quantum universal enveloping algebras of symmetries in constructing non-commutative geometry of the space-time including vector bundles, measure, equations of motion and their solutions is discussed. In the framework of the twist theory the Klein-Gordon-Fock and Dirac equations on the quantum Minkowski space are studied from this point of view for the simplest quantum deformation of the Lorentz algebra induced by its Cartan subalgebra twist. 1 The problem of building non-commutative models of the space-time arose in connection with attempts to formulate quantum field theory on this new basis, that could be free from difficulties inherent to the classical differential geometry description. Numerous publications on that matter address it in various aspects, using deformation of the

P. P. Kulish; A. I. Mudrov

1999-01-01T23:59:59.000Z

110

Enhanced Geometry Fluctuations in Minkowski and Black Hole Spacetimes  

E-Print Network (OSTI)

We will discuss selected physical effects of spacetime geometry fluctuations, especially the operational signatures of geometry fluctuations and their effects on black hole horizons. The operational signatures which we discuss involve the effects of the fluctuations on images, and include luminosity variations, spectral line broadening and angular blurring. Our main interest will be in black hole horizon fluctuations, especially horizon fluctuations which have been enhanced above the vacuum level by gravitons or matter in squeezed states. We investigate whether these fluctuations can alter the thermal character of a black hole. We find that this thermal character is remarkably robust, and that Hawking's original derivation using transplanckian modes does not seem to be sensitive even to enhanced horizon fluctuations.

R. T. Thompson; L. H. Ford

2008-02-12T23:59:59.000Z

111

Collective neutrino oscillations in non-spherical geometry  

E-Print Network (OSTI)

The rich phenomenology of collective neutrino oscillations has been studied only in one-dimensional or spherically symmetric systems. Motivated by the non-spherical example of coalescing neutron stars, presumably the central engines of short gamma-ray bursts, we use the Liouville equation to formulate the problem for general source geometries. Assuming the neutrino ensemble displays self-maintained coherence, the problem once more becomes effectively one-dimensional along the streamlines of the overall neutrino flux. This approach for the first time provides a formal definition of the ``single-angle approximation'' frequently used for supernova neutrinos and allows for a natural generalization to non-spherical geometries. We study the explicit example of a disk-shaped source as a proxy for coalescing neutron stars.

Basudeb Dasgupta; Amol Dighe; Alessandro Mirizzi; Georg G. Raffelt

2008-05-21T23:59:59.000Z

112

Experimental study of flame propagation in semiconfined geometries with obstacles  

DOE Green Energy (OSTI)

Accidents in which large quantities of liquefied natural gas (LNG) or other combustible materials are spilled can potentially lead to disastrous consequences, especially if the dispersing combustible cloud finds a suitable ignition source. So far, very little is known about the detailed behavior of a large burning cloud. Full-scale experiments are economically prohibitive, and therefore one must rely on laboratory and field experiments of smaller size, scaling up the results to make predictions about larger spill accidents. In this paper we describe our laboratory-scale experiments with a combustible propane/air mixture in various partially confined geometries. We summarize the experimental results and compare them with calculated results based on numerical simulations of the experiments. Our observations suggest that the geometry of the partial confinement is of primary importance; turbulence-producing obstacles can cause acceleration in the flame front and, more important, can cause a faster burnout of the combustible vapor.

Urtiew, P.A.; Brandeis, J.; Hogan, W.J.

1982-02-08T23:59:59.000Z

113

Directional Entanglement of Quantum Fields with Quantum Geometry  

E-Print Network (OSTI)

A modification of quantum field theory on large scales is conjectured to result from effects of Planck scale limits on directional information. Transversely localized solutions of the relativistic wave equation are used to show that the path of a massless particle with wavelength $\\lambda$ that travels a distance $z$ has a wave function with indeterminacy in direction given by the diffraction scale, $\\langle \\Delta \\theta^2\\rangle > \\sqrt{2}\\lambda /\\pi z$. It is conjectured that the spatial structure of all quantum field states is influenced by a new kind of directional indeterminacy of quantum geometry set by the Planck length, $l_P$, that does not occur in the usual classical background geometry. Entanglement of field and geometry states is described in the small angle approximation. It is shown to have almost no effect on local measurements, microscopic particle interactions, or measurements of propagating states that depend only on longitudinal coordinates, but to significantly alter field states in systems larger than $\\approx \\lambda^2/l_P $ that depend on transverse coordinates or direction. It reduces the information content of fields in large systems, consistent with holographic bounds from gravitation theory, and may lead to quantum-geometrical directional fluctuations of massive bodies detectable with interferometers. Possible connections are discussed with field vacuum energy, black hole information, and inflationary fluctuations.

Craig J. Hogan

2013-12-30T23:59:59.000Z

114

Deterministic point inclusion methods for computational applications with complex geometry  

Science Conference Proceedings (OSTI)

A fundamental problem in computation is finding practical and efficient algorithms for determining if a query point is contained within a model of a three-dimensional solid. The solid is modeled using a general boundary representation that can contain polygonal elements and/or parametric patches.We have developed two such algorithms: the first is based on a global closest feature query, and the second is based on a local intersection query. Both algorithms work for two- and three-dimensional objects. This paper presents both algorithms, as well as the spatial data structures and queries required for efficient implementation of the algorithms. Applications for these algorithms include computational geometry, mesh generation, particle simulation, multiphysics coupling, and computer graphics. These methods are deterministic in that they do not involve random perturbations of diagnostic rays cast from the query point in order to avoid unclean or singular intersections of the rays with the geometry. Avoiding the necessity of such random perturbations will become increasingly important as geometries become more convoluted and complex.

Khamayseh, Ahmed; Kuprat, Andrew P.

2008-11-21T23:59:59.000Z

115

DETERMINISTIC POINT INCLUSION METHODS FOR COMPUTATIONAL APPLICATIONS WITH COMPLEX GEOMETRY.  

Science Conference Proceedings (OSTI)

A fundamental problem in computation is finding practical and efficient algorithms for determining if a query point is contained within a model of a three-dimensional solid. The solid is modeled using a general boundary representation that can contain polygonal elements and/or parametric patches. We have developed two such algorithms: the first is based on a global closest feature query, and the second is based on a local intersection query. Both algorithms work for two- and three-dimensional objects. This paper presents both algorithms, as well as the spatial data structures and queries required for efficient implementation of the algorithms. Applications for these algorithms include computational geometry, mesh generation, particle simulation, multiphysics coupling, and computer graphics. These methods are deterministic in that they do not involve random perturbations of diagnostic rays cast from the query point in order to avoid "unclean" or "singular" intersections of the rays with the geometry. Avoiding the necessity of such random perturbations will become increasingly important as geometries become more convoluted and complex.

Khamayseh, Ahmed K [ORNL; Kuprat, Andrew [Los Alamos National Laboratory (LANL)

2008-01-01T23:59:59.000Z

116

Vehicle Technologies Office: 3-D Animation Shows Complex Geometry of Diesel  

NLE Websites -- All DOE Office Websites (Extended Search)

3-D Animation Shows 3-D Animation Shows Complex Geometry of Diesel Particulates to someone by E-mail Share Vehicle Technologies Office: 3-D Animation Shows Complex Geometry of Diesel Particulates on Facebook Tweet about Vehicle Technologies Office: 3-D Animation Shows Complex Geometry of Diesel Particulates on Twitter Bookmark Vehicle Technologies Office: 3-D Animation Shows Complex Geometry of Diesel Particulates on Google Bookmark Vehicle Technologies Office: 3-D Animation Shows Complex Geometry of Diesel Particulates on Delicious Rank Vehicle Technologies Office: 3-D Animation Shows Complex Geometry of Diesel Particulates on Digg Find More places to share Vehicle Technologies Office: 3-D Animation Shows Complex Geometry of Diesel Particulates on AddThis.com... 3-D Animation Shows Complex Geometry of Diesel Particulates

117

Long Atmospheric Waves and the Polar-Plane Approximation to the Earths Spherical Geometry  

Science Conference Proceedings (OSTI)

The spherical geometry of the earth is replaced by polar cylindrical geometry, with a plane tangential to the earth at the pole. The resulting frequency and structure of free motions in an isothermal, adiabatic atmosphere with a resting basic ...

Alison F. C. Bridger; Duane E. Stevens

1980-03-01T23:59:59.000Z

118

Modeling and sensitivity analysis of aircraft geometry for multidisciplinary optimization problems  

E-Print Network (OSTI)

A new geometry management paradigm for aircraft design utilizes Computer Aided Design (CAD) systems as the source for consistent geometry models across design phases and analysis tools. Yet various challenges inhibit the ...

Lazzara, David S. (David Sergio), 1980-

2012-01-01T23:59:59.000Z

119

OpenFlipper: an open source geometry processing and rendering framework  

Science Conference Proceedings (OSTI)

In this paper we present OpenFlipper, an extensible open source geometry processing and rendering framework. OpenFlipper is a free software toolkit and software development platform for geometry processing algorithms. It is mainly developed in the context ... Keywords: geometry processing, open source, software framework

Jan Mbius; Leif Kobbelt

2010-06-01T23:59:59.000Z

120

Bibliography Parabolic Geometries and Weyl connections Nearly invariant calculus (Wunsch's) nearly invariant calculus for parabolic  

E-Print Network (OSTI)

Bibliography Parabolic Geometries and Weyl connections Nearly invariant calculus (W¨unsch's) nearly invariant calculus for parabolic geometries Jan Slov´ak Masaryk University, Brno, Czech Republic joint work;Bibliography Parabolic Geometries and Weyl connections Nearly invariant calculus Structure 1 Bibliography 2

Olver, Peter

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Parabolic geometries and normal Weyl structures First BGG operators and special solutions  

E-Print Network (OSTI)

Parabolic geometries and normal Weyl structures First BGG operators and special solutions structures & BGG solutions #12;Parabolic geometries and normal Weyl structures First BGG operators to a parabolic geometry. The first operator in each BGG sequence defines a geometric overdetermined system

Drmota, Michael

122

Parabolic geometries and normal Weyl structures First BGG operators and special solutions  

E-Print Network (OSTI)

Parabolic geometries and normal Weyl structures First BGG operators and special solutions structures & BGG solutions #12;Parabolic geometries and normal Weyl structures First BGG operators the machinery of BGG sequences. Andreas Cap Weyl structures & BGG solutions #12;Parabolic geometries and normal

Drmota, Michael

123

Five lectures on optimal transportation: Geometry, regularity and applications  

E-Print Network (OSTI)

In this series of lectures we introduce the Monge-Kantorovich problem of optimally transporting one distribution of mass onto another, where optimality is measured against a cost function c(x,y). Connections to geometry, inequalities, and partial differential equations will be discussed, focusing in particular on recent developments in the regularity theory for Monge-Ampere type equations. An application to microeconomics will also be described, which amounts to finding the equilibrium price distribution for a monopolist marketing a multidimensional line of products to a population of anonymous agents whose preferences are known only statistically.

Guillen, Nestor

2010-01-01T23:59:59.000Z

124

On Information Theory, Spectral Geometry and Quantum Gravity  

E-Print Network (OSTI)

We show that there exists a deep link between the two disciplines of information theory and spectral geometry. This allows us to obtain new results on a well known quantum gravity motivated natural ultraviolet cutoff which describes an upper bound on the spatial density of information. Concretely, we show that, together with an infrared cutoff, this natural ultraviolet cutoff beautifully reduces the path integral of quantum field theory on curved space to a finite number of ordinary integrations. We then show, in particular, that the subsequent removal of the infrared cutoff is safe.

Achim Kempf; Robert Martin

2007-08-01T23:59:59.000Z

125

Color Printer Characterization Using a Computational Geometry Approach  

E-Print Network (OSTI)

We propose a method for the colorimetric characterization of a printer which can also be applied to any other type of digital image reproduction device. The method is based on a computational geometry approach. It uses a 3D triangulation technique to build a tetrahedral partition of the printer color gamut volume and it generates a surrounding structure enclosing the definition domain. The characterization provides the inverse transformation from the device-independent color space CIELAB to the device-dependent color space CMY, taking into account both colorimetric properties of the printer, and color gamut mapping.

Jon Yngve Hardeberg; Francis Schmitt

1998-01-01T23:59:59.000Z

126

Ion source operation with different magnetic confinement geometries  

DOE Green Energy (OSTI)

A comparison has been made between the longitudinal line cusp and the ''continuous'' checkerboard magnet geometries. We find that the checkerboard arrangement can provide a larger uniform density profile with approximately 20% less plasma density than the longitudinal line cusp. Results seem to indicate that the reduction in plasma density is closely related to the containment of primary ionizing electrons by the permanent magnets. A new magneto-electrostatic containment scheme was generated by using an internal magnetic cage system. The overall efficiency of this ion source was increased when it was operated with a xenon or argon plasma.

Leung, K.N.; Ehlers, K.W.

1984-03-01T23:59:59.000Z

127

Single chamber fuel cells: Flow geometry, rate and composition considerations  

DOE Green Energy (OSTI)

Four different single chamber fuel cell designs were compared using propane-air gas mixtures. Gas flow around the electrodes has a significant influence on the open circuit voltage and the power density of the cell. The strong influence of flow geometry is likely due to its effect on gas composition, particularly on the oxygen chemical potential at the two electrodes as a result of gas mixing. The chamber design which exposes the cathode first to the inlet gas was found to yield the best performance at lower flow rates, while the open tube design with the electrodes equally exposed to the inlet gas worked best at higher flow rates.

Stefan, Ionel C.; Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

2003-11-17T23:59:59.000Z

128

Quantum Geometry of the Dynamical Space-time  

E-Print Network (OSTI)

Quantum theory of field (extended) objects without a priori space-time geometry has been represented. Intrinsic coordinates in the tangent fibre bundle over complex projective Hilbert state space $CP(N-1)$ are used instead of space-time coordinates. The fate of quantum system modeled by the generalized coherent states is rooted in this manifold. Dynamical (state-dependent) space-time arises only at the stage of the quantum "yes/no" measurement. The quantum measurement of the gauge ``field shell'' of the generalized coherent state is described in terms of the affine parallel transport of the local dynamical variables in $CP(N-1)$.

Peter Leifer

2006-11-20T23:59:59.000Z

129

ELECTRON CYCLOTRON CURRENT DRIVE EFFICIENCY IN GENERAL TOKAMAK GEOMETRY  

SciTech Connect

Green's-function techniques are used to calculate electron cyclotron current drive (ECCD) efficiency in general tokamak geometry in the low-collisionality regime. Fully relativistic electron dynamics is employed in the theoretical formulation. The high-velocity collision model is used to model Coulomb collisions and a simplified quasi-linear rf diffusion operator describes wave-particle interactions. The approximate analytic solutions which are benchmarked with a widely used ECCD model, facilitate time-dependent simulations of tokamak operational scenarios using the non-inductive current drive of electron cyclotron waves.

LIN-LUI,Y.R; CHAN,V.S; PRATER,R

2003-03-01T23:59:59.000Z

130

A comparison of the conductor requirements for energy storage devices made with ideal coil geometries  

DOE Green Energy (OSTI)

Superconducting Magnetic Energy Storage (SMES) plants have been proposed in both solenoidal and toroidal geometries. The former is efficient in terms of the quantity of superconductor required per unit of stored energy. For applications where a fringe field could be a problem, the toroidal geometry, which requires at least a factor of two more material, has been proposed. In addition to the solenoid and toroid, other geometries are possible, such as linear multipoles and spherical coils. These geometries have been considered for use in applications other than energy storage. In this report, the effectiveness (quantity of superconductor/stored energy) is calculated for various coil geometries. 7 refs., 4 tabs.

Hassenzahl, W.

1988-08-01T23:59:59.000Z

131

Quantum Algorithm for Molecular Properties and Geometry Optimization  

E-Print Network (OSTI)

It is known that quantum computers, if available, would allow an exponential decrease in the computational cost of quantum simulations. We extend this result to show that the computation of molecular properties (energy derivatives) could also be sped up using quantum computers. We provide a quantum algorithm for the numerical evaluation of molecular properties, whose time cost is a constant multiple of the time needed to compute the molecular energy, regardless of the size of the system. Molecular properties computed with the proposed approach could also be used for the optimization of molecular geometries or other properties. For that purpose, we discuss the benefits of quantum techniques for Newton's method and Householder methods. Finally, global minima for the proposed optimizations can be found using the quantum basin hopper algorithm, which offers an additional quadratic reduction in cost over classical multi-start techniques.

Kassal, Ivan

2009-01-01T23:59:59.000Z

132

Quantum Algorithm for Molecular Properties and Geometry Optimization  

E-Print Network (OSTI)

It is known that quantum computers, if available, would allow an exponential decrease in the computational cost of quantum simulations. We extend this result to show that the computation of molecular properties (energy derivatives) could also be sped up using quantum computers. We provide a quantum algorithm for the numerical evaluation of molecular properties, whose time cost is a constant multiple of the time needed to compute the molecular energy, regardless of the size of the system. Molecular properties computed with the proposed approach could also be used for the optimization of molecular geometries or other properties. For that purpose, we discuss the benefits of quantum techniques for Newton's method and Householder methods. Finally, global minima for the proposed optimizations can be found using the quantum basin hopper algorithm, which offers an additional quadratic reduction in cost over classical multi-start techniques.

Ivan Kassal; Aln Aspuru-Guzik

2009-08-13T23:59:59.000Z

133

Aspects of metric-like higher-spin geometry  

Science Conference Proceedings (OSTI)

We consider the higher-derivative equations obtained setting to zero the divergence of the higher-spin curvatures in metric-like form, showing their equivalence to the second-order equations emerging from the tensionless limit of open string field theory, propagating reducible spectra of particles with different spins. This result can be viewed as complementary to the possibility of setting to zero a single trace of the higher-spin field strengths, yielding an equation known to imply Fronsdal's equation in the compensator form. We review the general context and results obtained in the investigation of metric-like higher-spin geometry, the structure of the corresponding non-local actions, together with their links to more conventional, local forms including a recently proposed one for higher-spin theories with transverse gauge invariance.

Francia, D. [Centro Studi e Ricerche E. Fermi, piazza del Viminale 1, I-00184 Roma, Italy and Scuola Normale Superiore and INFN, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)

2012-09-24T23:59:59.000Z

134

Corbino-geometry Josephson weak links in thin superconducting films  

Science Conference Proceedings (OSTI)

I consider a Corbino-geometry superconducting-normal-superconducting Josephson weak link in a thin superconducting film, in which current enters at the origin, flows outward, passes through an annular Josephson weak link, and leaves radially. In contrast to sandwich-type annular Josephson junctions, in which the gauge-invariant phase difference obeys the sine-Gordon equation, here the gauge-invariant phase difference obeys an integral equation. I present exact solutions for the gauge-invariant phase difference across the weak link when it contains an integral number N of Josephson vortices and the current is zero. I then study the dynamics when a current is applied, and I derive the effective resistance and the viscous drag coefficient; I compare these results with those in sandwich-type junctions. I also calculate the critical current when there is no Josephson vortex in the weak link but there is a Pearl vortex nearby.

Clem, John R.

2010-11-29T23:59:59.000Z

135

Duality of Positive Currents and Plurisubharmonic Functions in Calibrated Geometry  

E-Print Network (OSTI)

Recently the authors showed that there is a robust potential theory attached to any calibrated manifold (X,\\phi). In particular, on X there exist \\phi-plurisubharmonic functions, \\phi-convex domains, \\phi-convex boundaries, etc., all inter-related and having a number of good properties. In this paper we show that, in a strong sense, the plurisubharmonic functions are the polar duals of the \\phi-submanifolds, or more generally, the \\phi-currents studied in the original paper on calibrations. In particular, we establish an analogue of Duval-Sibony Duality which characterizes points in the \\phi-convex hull of a compact set K in X in terms of \\phi-positive Green's currents on X and Jensen measures on K. We also characterize boundaries of \\phi-currents entirely in terms of \\phi-plurisubharmonic functions. Specific calibrations are used as examples throughout. Analogues of the Hodge Conjecture in calibrated geometry are considered.

Harvey, F Reese

2007-01-01T23:59:59.000Z

136

Electronic Structure and Geometries of Small Compound Metal Clusters  

DOE Green Energy (OSTI)

During the tenure of the DOE grant DE-FG05-87EI145316 we have concentrated on equilibrium geometries, stability, and the electronic structure of transition metal-carbon clusters (met-cars), clusters designed to mimic the chemistry of atoms, and reactivity of homo-nuclear metal clusters and ions with various reactant molecules. It is difficult to describe all the research the authors have accomplished as they have published 38 papers. In this report, they outline briefly the salient features of their work on the following topics: (1) Designer Clusters: Building Blocks for a New Class of Solids; (2) Atomic Structure, Stability, and Electronic Properties of Metallo-Carbohedrenes; (3) Reactivity of Metal Clusters with H{sub 2} and NO; and (4) Anomalous Spectroscopy of Li{sub 4} Clusters.

NONE

1999-04-14T23:59:59.000Z

137

TPV efficiency measurements and predictions for a closed cavity geometry  

DOE Green Energy (OSTI)

A thermophotovoltaic (TPV) efficiency measurement, within a closed cavity, is an integrated test which incorporates four fundamental parameters of TPV direct energy conversion. These are: (1) the TPV devices, (2) spectral control, (3) a radiation/photon source, and (4) closed cavity geometry effects. The overall efficiency of the TPV device is controlled by the TP cell performance, the spectral control characteristics, the radiator temperature and the geometric arrangement. Controlled efficiency measurements and predictions provide valuable feedback on all four. This paper describes and compares two computer codes developed to model 16, 1 cm{sup 2} TPV cells (in a 4 x 4 configuration) in a cavity geometry. The first code, subdivides the infrared spectrum into several bands and then numerically integrates over the spectrum to provide absorbed heat flux and cell electrical output performance predictions (assuming infinite parallel plates). The second code, utilizes a Monte Carlo Photon Transport code that tracks photons, from birth at the radiation source, until they either escape or are absorbed. Absorption depends upon energy dependent reflection probabilities assigned to every geometrical surface within the cavity. The model also has the capability of tallying above and below bandgap absorptions (as a function of location) and can support various radiator temperature profiles. The arrays were fabricated using 0.55 eV InGaAs cells with Si/SiO interference filters for spectral control and at steady state conditions, array efficiency was calculated as the ratio of the load matched power to its absorbed heat flux. Preliminary experimental results are also compared with predictions.

Gethers, C.K.; Ballinger, C.T.; Postlethwait, M.A.; DePoy, D.M.; Baldasaro, P.F.

1997-05-01T23:59:59.000Z

138

TPV efficiency predictions and measurements for a closed cavity geometry  

DOE Green Energy (OSTI)

A thermophotovoltaic (TPV) efficiency measurement, within a closed cavity, is an integrated test which incorporates four fundamental parameters of TPV direct energy conversion. These are: (1) the TPV devices, (2) spectral control, (3) a radiation/photon source, and (4) closed cavity geometry affects. The overall efficiency of the TPV device is controlled by the TPV cell performance, the spectral control characteristics, the radiator temperature and the geometric arrangement. Controlled efficiency measurements and predictions provide valuable feedback on all four. This paper describes and compares two computer codes developed to model 16, 1 cm{sup 2} TPV cells (in a 4x4 configuration) in a cavity geometry. The first code subdivides the infrared spectrum into several bands and then numerically integrates over the spectrum to provide absorbed heat flux and cell performance predictions (assuming infinite parallel plates). The second utilizes a Monte Carlo Ray-Tracing code that tracks photons, from birth at the radiation source, until they either escape or are absorbed. Absorption depends upon energy dependent reflection probabilities assigned to every geometrical surface within the cavity. The model also has the capability of tallying above and below bandgap absorptions (as a function of location) and can support various radiator temperature profiles. The arrays are fabricated using 0.55 eV InGaAs cells with Si/SiO interference filters for spectral control and at steady state conditions, array efficiency was calculated as the ratio of the load matched power to its absorbed heat flux. Preliminary experimental results are also compared with predictions.

Gethers, C.K.; Ballinger, C.T.; Postlethwait, M.A.; DePoy, D.M.; Baldasaro, P.F. [Lockheed Martin Corp., Schenectady, NY (United States)

1997-05-01T23:59:59.000Z

139

Ecophysiology of dryland corn and grain sorghum as affected by alternative planting geometries and seeding rates.  

E-Print Network (OSTI)

??Previous work in the High Plains with alternative planting geometries of corn and grain sorghum has shown potential benefits in dryland production. Studies conducted in (more)

Haag, Lucas A.

2013-01-01T23:59:59.000Z

140

Design, fabrication and test on piezoelectric energy harvesters with non-traditional geometries.  

E-Print Network (OSTI)

??Unimorph piezoelectric cantilevers with non-traditional surface geometries were investigated by theoretical calculations, finite element models, and sample tests. The study shows the average output voltage (more)

Wang, Lei, 1987-

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Electron transfer in systems of well-defined geometry  

DOE Green Energy (OSTI)

Two mesopyropheophorbide macrocycles can be joined via two covalent linkages to produce a cyclophane. It is possible to insert one or two Mg atoms into the cyclophane. The Qy transitions of the macrocycles are nearly orthogonal. The visible absorption spectrum of the monometal cyclophane is nearly a superposition of the spectra of the monomers. Emission from the monometal cyclophane arises primarily from the red most absorbing chromophore. The excited state difference spectrum shows that both macrocycles are excited. Fluorescence lifetimes of the monometal cyclophane decrease with increasing dielectric strength. Changes in the fluorescence and the triplet yield parallel the shortening of the singlet lifetime. Thus the radiative rate is solvent independent. This is in contrast to what one would expect if the emitting state had charge transfer character. Since the fluorescence lifetime is dependent on dielectric, the nonradiative relaxation from the singlet state is due to formation of a radical pair. The decay rate of the postulated radical pair was monitored by observing the kinetics of ground state repopulation. For the geometry of this cyclophane, electron transfer proceeds relatively slowly (k = 3 x 10/sup 9/ sec/sup -1/) in the forward direction. Modeling calculations indicate that the rate of annihilation of the radical pair may decrease as the solvent dielectric decreases.

Overfield, R.E.; Kaufmann, K.J.; Wasielewski, M.R.

1980-01-01T23:59:59.000Z

142

Hydrodynamically Lubricated Rotary Shaft Having Twist Resistant Geometry  

SciTech Connect

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

Dietle, Lannie (Houston, TX); Gobeli, Jeffrey D. (Houston, TX)

1993-07-27T23:59:59.000Z

143

Three-dimensional visualization of reactive flows in complex geometries  

SciTech Connect

The visualization of fluid flows has become more challenging, as recent advancements in computational methods have increased the complexity and size of simulations. Our objective is to develop a flexible flow visualization tool for fluid simulations that include the full physics and geometrical complexities found in modeling practical combustion systems, such as internal combustion engines. The challenges to flow visualization come from: (1) the large simulation output, especially when using massively parallel computers; (2) the increasingly complex geometries that include moving surfaces such as pistons and valves; (3) the complex physical phenomena in realistic problems of fuel injection, combustion fronts, boundary flows, and large scale turbulence; and (4) the numerical complexity of indirect addressing of computational elements, variable mesh connectivity, distorted elements, and moving meshes. We have developed a visualization program that addresses these complexities. The program was developed as a post-processor to the KIVA family of codes for reactive flow simulations. Because of the complexity of the KIVA codes, the visualization program is very versatile and applicable to any code with meshes of arbitrary hexahedrons. No comparable commercial visualization package could be found. To visualize the fluid flow, we use mass-less tracer particles that follow the movement of the fluid as determined from output files from the simulation. The movement of the tracer particles is based on a second-order spatial and temporal interpolation of the fluid velocities from successive simulation output files. The visualization program runs on a Silicon Graphics IRIS GTX workstation.

Fairfield, M.S.

1995-02-01T23:59:59.000Z

144

Complex Geometry Creation and Turbulent Conjugate Heat Transfer Modeling  

Science Conference Proceedings (OSTI)

The multiphysics capabilities of COMSOL provide the necessary tools to simulate the turbulent thermal-fluid aspects of the High Flux Isotope Reactor (HFIR). Version 4.1, and later, of COMSOL provides three different turbulence models: the standard k-{var_epsilon} closure model, the low Reynolds number (LRN) k-{var_epsilon} model, and the Spalart-Allmaras model. The LRN meets the needs of the nominal HFIR thermal-hydraulic requirements for 2D and 3D simulations. COMSOL also has the capability to create complex geometries. The circular involute fuel plates used in the HFIR require the use of algebraic equations to generate an accurate geometrical representation in the simulation environment. The best-estimate simulation results show that the maximum fuel plate clad surface temperatures are lower than those predicted by the legacy thermal safety code used at HFIR by approximately 17 K. The best-estimate temperature distribution determined by COMSOL was then used to determine the necessary increase in the magnitude of the power density profile (PDP) to produce a similar clad surface temperature as compared to the legacy thermal safety code. It was determined and verified that a 19% power increase was sufficient to bring the two temperature profiles to relatively good agreement.

Bodey, Isaac T [ORNL; Arimilli, Rao V [ORNL; Freels, James D [ORNL

2011-01-01T23:59:59.000Z

145

Meeting on flows of granular materials in complex geometries  

Science Conference Proceedings (OSTI)

The International Energy Agency Fossil Fuel Multiphase Flow Sciences Agreement has been in effect since 1986. The traditional mechanism for the effort has been information exchange, effected by the inclusion of scientists in annual Executive committee meetings, by exchange of reports and papers, and by visits of scientists to one another`s institutions. In a sequence of informal meetings and at the 1993 Executive committee meeting, held in Pittsburgh, US in March 1994, it was decided that more intensive interactions could be productive. A candidate for such interactions would be specific projects. Each of these would be initiated through a meeting of scientists in which feasibility of the particular project was decided, followed by relatively intense international co-operation in which the work would be done. This is a report of the first of these meetings. Official or unofficial representatives from Canada, italy, japan, mexico, the United Kingdom, and the US met in Albuquerque, New Mexico, US, to consider the subject Flows of Granular Materials in Complex Geometries. Representatives of several other countries expressed interest but were unable to attend this meeting. Sixteen lectures were given on aspects of this topic. It was decided that a co-operative effort was desirable and possible. The most likely candidate for the area of study would be flows in bins and hoppers. Each of the countries wishing to co-operate will pursue funding for its effort. This report contains extended abstracts of the sixteen presentations and a transcription of the final discussion.

Passman, S.L.; Fukushima, E.; Evans, R.E. [eds.

1994-11-01T23:59:59.000Z

146

X-ray Diagnostics of Broad Absorption Line Quasar Geometry  

E-Print Network (OSTI)

A new generation of sensitive X-ray measurements are indicating that the existence of X-ray attenuation column densities, $N_{H}>10^{24}\\mathrm{cm}^{-2}$ is quite common amongst broad absorption line quasars (BALQSOs). This is significant to the geometry of the broad absorption line (BAL) outflow. In particular, such an X-ray shield also shields equatorial accretion disk winds from the UV, thereby preventing high velocity equatorial outflows from being launched. By contrast, bipolar winds initiated by continuum radiation pressure from the funnel of a slim accretion disk flare outward (like a trumpet) and offer vastly different absorbing columns to the X-ray and UV emission which are emitted from distinct regions of the disk, $\\sim 6M$ and $\\sim 10M-40M$, respectively (where $M$ is the radius of the black hole). Recent numerical work indicates that it is also possible to launch bipolar outflows from the inner regions of a thin disk. The recent discovery with VLBI that the Galactic analog of a BALQSO, the X-ray binary Circinus X-1 (with high velocity P Cygni X-ray absorption lines) is viewed virtually along the radio jet axis (and therefore along the spin axis of the black hole and the normal to the accretion disk) has rekindled interest in the bipolar models of BALQSOs. We explore this possibility by studying the nearest BAL QSO, MRK 231. High resolution 2-D optical spectroscopy and VLBI mappings of the radio jet axis indicates that the BAL outflow is parallel to the parsec scale radio jet.

Brian Punsly; Sebastian Lipari

2005-03-09T23:59:59.000Z

147

A Direct Calculation of Current Drive in Toroidal Geometry J. C. Wright and C. K. Phillips  

E-Print Network (OSTI)

field in the quasilinear flux are used to evaluate the current in a specified toroidal geometry. PACS-induced quasilinear flux in a toroidal geometry and a Green's function for the current. An expression, , was parameter- ized by combining a ray­tracing solution for the wave fields with the quasilinear flux, ql

148

A Direct Calculation of Current Drive in Toroidal Geometry J. C. Wright and C. K. Phillips  

E-Print Network (OSTI)

field in the quasilinear flux are used to evaluate the current in a specified toroidal geometry. PACS­induced quasilinear flux in a toroidal geometry and a Green's function for the current. An expression calculation of the current using a quasilinear flux model for a spectrum of parallel wavenum­ bers, k k j k

149

Modelling using UML diagrams of an intelligent system for the automatic demonstration of geometry theorems  

Science Conference Proceedings (OSTI)

In this work will be presented the design of an intelligent system destined for development process of demonstrating abilities for geometry theorems. This system will make available to user a proof assistant which will allow interactive vizualization ... Keywords: Java, automatic demonstration theorems, geometry, intelligent software, prolog

Anca Iordan; Manuela P?noiu; Ioan Baciu; Corina Daniela Cun?an

2010-09-01T23:59:59.000Z

150

Quantum mechanics and gravity as preclusion principles of four dimensional geometries  

E-Print Network (OSTI)

The goal of this paper is to employ a "preclusion principle" originally suggested by Rafael Sorkin in order to come up with a relativistically covariant model of quantum mechanics and gravity. Space-time is viewed as geometry as opposed to dynamics, and "unwanted" histories in that geometry are precluded.

Roman Sverdlov

2008-10-01T23:59:59.000Z

151

Impact of lattice geometry distortion due to ageing on selected physics parameters of a CANDU reactor  

SciTech Connect

In this paper, results related to a limited scope assessment of the geometry-distortion-induced effects on key reactor physics parameters of a CANDU reactor are discussed. These results were generated by simulations using refined analytical methods and detailed modeling of CANDU reactor core with aged lattice cell geometry. (authors)

Tholammakkil, J. [Canadian Nuclear Safety Commission, P.O. Box 1046, Ottawa, Ont. (Canada); Rahnema, F. [Georgia Inst. of Technology, Atlanta, GA 30332-0405 (United States); Ilas, G. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Stamm'ler, R. [Studsvik Scandpower AS, P.O. Box 15, NO-2027 Kjeller (Norway); Khotylev, V.; Serghiuta, D. [Canadian Nuclear Safety Commission, P.O. Box 1046, Ottawa, Ont. (Canada)

2006-07-01T23:59:59.000Z

152

Constructions of dynamic geometry: A study of the interpretative flexibility of educational software in classroom practice  

Science Conference Proceedings (OSTI)

The idea of 'interpretative flexibility' underpins new approaches to studying technological artefacts and curricular resources in use. This paper opens by reviewing - in this light - the evolving design of dynamic geometry, its pioneering use within ... Keywords: Applications in subject areas, Curriculum materials, Dynamic geometry, Educational software, Pedagogical issues, School mathematics, Secondary education, Teacher thinking, Teaching practices, Technology integration

Kenneth Ruthven; Sara Hennessy; Rosemary Deaney

2008-08-01T23:59:59.000Z

153

A Stochastic/Perturbation Global Optimization Algorithm for Distance Geometry Problems  

Science Conference Proceedings (OSTI)

We present a new global optimization approach for solving exactly or inexactly constrained distance geometry problems. Distance geometry problems are concerned with determining spatial structures from measurements of internal distances. They arise ... Keywords: Lennard-Jones cluster, Molecular conformation, global optimization

Zhihong Zou; Richard H. Bird; Robert B. Schnabel

1997-07-01T23:59:59.000Z

154

NA Standards | Valence Geometries | Nitrog. Bases Table 1  

NLE Websites -- All DOE Office Websites (Extended Search)

Table 1: References for Nitrogenous Base Structures Table 1: References for Nitrogenous Base Structures used in Lester Clowney, Shri C. Jain, A. R. Srinivasan, John Westbrook, Wilma K. Olson, and Helen M. Berman. "Geometric Parameters in Nucleic Acids: Nitrogenous Bases. (1996) J. Am. Chem. Soc. 118, 519-529. Cytosine -------------------------------------------------------------------------- CSD ID Compound Reference -------------------------------------------------------------------------- acytid alpha-cytidine Post, M.L., et al. Biochim. Biophys. Acta, 1977, 479, 133 bivvil 2',3'-O-(tetraisopropyl-1,3-disiloxanediyl)-cytidine Hoogendorp J.D and Romers, C Acta Cryst., 1982, B38, 2738 bofwoi 2'-deoxy-2'-fluorocytidine dihydrate Marck, C., et al. J. Mol. Struct., 1982, 82, 77

155

MOCUM: A two-dimensional method of characteristics code based on unstructured meshing for general geometries  

Science Conference Proceedings (OSTI)

A transport theory code MOCUM based on the Method of Characteristics (MOC) as the flux solver with an advanced general geometry processor is developed for two-dimensional lattice and full core neutronics modeling. The core structure is represented by Constructive Solid Geometry (CSG) that uses Boolean operations to build complex geometries from simple polygons. Arbitrary-precision arithmetic is also used in the process of building CSG objects to eliminate the round-off error from the commonly used double precision numbers. Then, the constructed core frame will be decomposed and refined into a conforming Delaunay triangulation to ensure the quality of the meshes. The MOC solver kernel is fully paralleled using OpenMP and the developed numerical code is validated by several benchmarks representing various core geometries. For the cases modeled, the maximum percentage error for multiplication factor and the pin power compared to reference values are 0.1% and 0.7% respectively. (authors)

Yang, X.; Satvat, N. [School of Nuclear Engineering, Purdue Univ., 400 Central Dr, West Lafayette, IN 47907 (United States)

2012-07-01T23:59:59.000Z

156

LES Analysis of the Aerodynamic Surface Properties for Turbulent Flows over Building Arrays with Various Geometries  

Science Conference Proceedings (OSTI)

This paper describes aerodynamic roughness properties for turbulent flows over various building arrays that represent realistic urban surface geometries. First, building morphological characteristics such as roughness density ?f and building ...

Hiromasa Nakayama; Tetsuya Takemi; Haruyasu Nagai

2011-08-01T23:59:59.000Z

157

Large-Scale Circulation and Production of Stratification: Effects of Wind, Geometry, and Diffusion  

Science Conference Proceedings (OSTI)

The combined effects of wind, geometry, and diffusion on the stratification and circulation of the ocean are explored by numerical and analytical methods. In particular, the production of deep stratification in a simply configured numerical model ...

Geoffrey K. Vallis

2000-05-01T23:59:59.000Z

158

Finite-geometry models of electric field noise from patch potentials in ion traps  

E-Print Network (OSTI)

We model electric field noise from fluctuating patch potentials on conducting surfaces by taking into account the finite geometry of the ion trap electrodes to gain insight into the origin of anomalous heating in ion traps. ...

Low, Guang Hao

159

Fluctuating-surface-current formulation of radiative heat transfer for arbitrary geometries  

E-Print Network (OSTI)

We describe a fluctuating-surface-current formulation of radiative heat transfer, applicable to arbitrary geometries in both the near and far field, that directly exploits efficient and sophisticated techniques from the ...

Rodriguez, Alejandro W.

160

Simulation and visualization of fields and energy flows in electric circuits with idealized geometries  

E-Print Network (OSTI)

This thesis develops a method to simulate and visualize the fields and energy flows in electric circuits, using a simplified physical model based on an idealized geometry. The physical models combine and extend previously ...

Ohannessian, Mesrob I., 1981-

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

On the Geostrophic Adjustment of an Isolated Lens: Dependence on Burger Number and Initial Geometry  

Science Conference Proceedings (OSTI)

Geostrophic adjustment of an isolated axisymmetric lens was examined to better understand the dependence of radial displacements and the adjusted velocity on the Burger number and the geometry of initial conditions. The behavior of the adjustment ...

Grant A. Stuart; Miles A. Sundermeyer; Dave Hebert

2011-04-01T23:59:59.000Z

162

Radiative Transfer in Cirrus Clouds. Part IV: On Cloud Geometry, Inhomogeneity, and Absorption  

Science Conference Proceedings (OSTI)

The effects of cloud geometry and inhomogeneity on the radiative properties of cirrus clouds are investigated by using the successive orders of scattering (SOS) approach for radiative transfer. This approach is an integral solution method that em ...

K. N. Liou; N. Rao

1996-11-01T23:59:59.000Z

163

Variable impedance energy dissipation on the micro-scale : field responsive fluids in novel geometries  

E-Print Network (OSTI)

The aim of this thesis was to further characterize the effectiveness of field responsive fluids (FRFs) in geometries pertinent to the soldier and to examine the effects of specific geometric and kinematic parameters, ...

Griffin, Ryan A

2006-01-01T23:59:59.000Z

164

Book Review: "Geometry of Quantum States" by Ingemar Bengtsson and Karol Zyczkowski (Cambridge University Press, 2006)  

E-Print Network (OSTI)

Invited book review, as submitted to the electronic database MathSciNet, of the 2006 Cambridge University Press book, "Geometry of Quantum States," by Ingemar Bengtsson and Karol Zyczkowski

Slater, Paul B

2009-01-01T23:59:59.000Z

165

The Vector Harmonic Transform Method for Solving Partial Differential Equations in Spherical Geometry  

Science Conference Proceedings (OSTI)

The development of computational methods for solving partial differential equations in spherical geometry is complicated by problems induced by the spherical coordinate system itself. Even though the solution is smooth in Cartesian coordinates, ...

Paul N. Swarztrauber

1993-12-01T23:59:59.000Z

166

Sensitivities of Orographic Precipitation to Terrain Geometry and Upstream Conditions in Idealized Simulations  

Science Conference Proceedings (OSTI)

This study examines how variations in relatively simple terrain geometries influence orographic precipitation and its spatial patterns of sensitivity to small changes in upstream conditions. An idealized three-dimensional model is used to simulate ...

Campbell D. Watson; Todd P. Lane

2012-04-01T23:59:59.000Z

167

NMR for Equilateral Triangular Geometry under Conditions of Surface Relaxivity - Analytical and Random Walk Solution  

E-Print Network (OSTI)

We consider analytical and numerical solution of NMR relaxation under the condition of surface relaxation in an equilateral triangular geometry. We present an analytical expression for the Green's function in this geometry. We calculate the transverse magnetic relaxation without magnetic gradients present, single-phase, both analytically and numerically. There is a very good match between the analytical and numerical results. We also show that the magnetic signal from an equilateral triangular geometry is qualitatively different from the known solution: plate, cylinder and sphere, in the case of a nonuniform initial magnetization. Non uniform magnetization close to the sharp corners makes the magnetic signal very fast multi exponential. This type of initial configuration fits qualitatively with the experimental results by Song et al.[1]. It should also be noted that the solution presented here can be used to describe absorption of a chemical substance in an equilateral triangular geometry (for a stationary fluid).

J. Finjord; A. Hiorth; U. H. a Lad; S. M. Skjaeveland

2005-08-18T23:59:59.000Z

168

Geometry-dependent trends in the scattering of van der Waals clusters from crystal surfaces  

SciTech Connect

Constrained configurations in linear and ring geometries along with a polyhedral structure of van der Waals clusters were used to observe classical molecular dynamics simulations of collisions of these clusters with a rigid surface. The constrained geometries tend to survive high-energy collisions intact while the minimized polyhedral structures tend to shatter. The constrained structures also tend to scatter nearer the specular angle. 36 refs., 9 figs., 1 tab.

Niesse, J.A.; Beauregard, J.N.; Mayne, H.R. [Univ. of New Hampshire, Durham, NH (United States)

1994-09-01T23:59:59.000Z

169

Acrylic Acid from 3-Hydroxypropionic Acid - Energy Innovation ...  

Technology Marketing Summary. 3-hydroxypropionic acid is readily converted to acrylic acid by conversion to the acid salt followed by treatment with a solid oxide ...

170

PRODUCTION OF TRIFLUOROACETIC ACID  

DOE Patents (OSTI)

A method is given for the production of improved yields of trifluoroacetic acid. The compound is prepared by oxidizing m-aminobenzotrifluoride with an alkali metal or alkaline earth metal permanganate at a temperature in the range of 80 deg C to 100 deg C while dissolved ln a mixture of water with glacial acetic acid and/or trifluoroacetic acid. Preferably a mixture of water and trifluoroacetic acid ls used as the solvent.

Haworth, W.N.; Stacey, M.

1949-07-19T23:59:59.000Z

171

Nucleic acid detection compositions  

DOE Patents (OSTI)

The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann (Madison, WI); Dahlberg, James L. (Madison, WI)

2008-08-05T23:59:59.000Z

172

Modifications of the beam profile in the new inclined crystal geometry  

SciTech Connect

The new inclined crystal geometry has been successfully used in high heat load X-ray monochromator tests. The important aspect of this geometry is that from a diffraction point of view, when properly aligned, is is a symmetric Bragg reflection; i.e., b = k{sub i} . n/k{sub out}.n = {minus}1. An interesting result of this geometry is that with a single reflection from an inclined crystal, the output X-ray beam shape changes dramatically while maintaining the same beam cross section area. For example, a parallel 8 keV input X-ray beam using Si(111) reflection, with an inclination angle of 70.5{degrees}, the output beam size is compressed by about a factor of 5.4 in one direction and expanded by the same factor in the other direction. This geometry can therefore, be used to alter the source line profile of in house X-ray generators and in some cases, be used to better match the sample size and the X-ray beam. The effect of this geometry on beam profiles, beam divergences and acceptance angles will be discussed.

Lee, W.K.; Macrander, A.T.

1991-10-01T23:59:59.000Z

173

Process for the preparation of lactic acid and glyceric acid  

DOE Patents (OSTI)

Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

2008-12-02T23:59:59.000Z

174

Overview of Geometry Representation in Monte Carlo Codes Ronald P. Kensek  

National Nuclear Security Administration (NNSA)

Overview of Geometry Representation Overview of Geometry Representation in Monte Carlo Codes Ronald P. Kensek Brian C. Franke Thomas W. Laub Leonard J. Lorence Matthew R. Martin Sandia National Laboratories Steve Warren Kansas State University Joint Russian-American Five-Laboratory Conference on Computational Mathematics / Physics Vienna, Austria June 19-23, 2005 Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States National Nuclear Security Administration and the Department of Energy under contract DE-AC04-94AL85000. 2 Problem Setup: Engineering designs CG vs. CAD Combinatorial Geometry (CG) * Engineering designs are not typically created in this format * No general automatic translation from CAD to CG yet exists * Problem setup is difficult: Creation

175

Fault and joint geometry at Raft River geothermal area, Idaho | Open Energy  

Open Energy Info (EERE)

and joint geometry at Raft River geothermal area, Idaho and joint geometry at Raft River geothermal area, Idaho Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Fault and joint geometry at Raft River geothermal area, Idaho Details Activities (1) Areas (1) Regions (0) Abstract: Raft River geothermal reservoir is formed by fractures in sedimentary strata of the Miocene and Pliocene Salt Lake Formation. The fracturing is most intense at the base of the Salt Lake Formation, along a decollement that dips eastward at less than 5 0 on top of metamorphosed Precambrian and Lower Paleozoic rocks. Core taken from less than 200 m above the decollement contains two sets of normal faults. The major set of faults dips between 50 0 and 70 0. These faults occur as conjugate pairs that are bisected by vertical extension fractures. The second set of faults

176

Final Report for the grant "Applied Geometry" (DOE DE-FG02-04ER25657)  

Science Conference Proceedings (OSTI)

The primary purpose of this 3-year DOE-funded research effort, now completed, was to develop consistent, theoretical foundations of computations on discrete geometry, to realize the promise of predictive and scalable management of large geometric datasets as handled routinely in applied sciences. Geometry (be it simple 3D shapes or higher dimensional manifolds) is indeed a central and challenging issue from the modeling and computational perspective in several sciences such as mechanics, biology, molecular dynamics, geophysics, as well as engineering. From digital maps of our world, virtual car crash simulation, predictive animation of carbon nano-tubes, to trajectory design of space missions, knowing how to process and animate digital geometry is key in many cross-disciplinary research areas.

Prof. Mathieu Desbrun

2009-05-20T23:59:59.000Z

177

Topological terms and the global symplectic geometry of the phase space in string theory  

E-Print Network (OSTI)

Using an imbedding supported background tensor approach for the differential geometry of an imbedded surface in an arbitrary background, we show that the topological terms associated with the inner and outer curvature scalars of the string worldsheet, have a dramatic effect on the global symplectic geometry of the phase space of the theory. By identifying the global symplectic potential of each Lagrangian term in the string action as the argument of the corresponding pure divergence term in a variational principle, we show that those topological terms contribute explicitly to the symplectic potential of any action describing strings, without modifying the string dynamics and the phase space itself. The variation (the exterior derivative on the phase space) of the symplectic potential generates the integral kernel of a covariant and gauge invariant symplectic structure for the theory, changing thus the global symplectic geometry of the phase space. Similar results for non-Abelian gauge theories and General Relativity are briefly discussed

R. Cartas-Fuentevilla

2004-04-01T23:59:59.000Z

178

THE EFFECT OF VARIOUS DETECTOR GEOMETRIES ON THE PERFORMANCE OF CZT USING ONE CRYSTAL  

Science Conference Proceedings (OSTI)

CdZnTe (CZT) continues to be a major thrust interest mainly due to its potential application as a room temperature radiation detector. The performance of CZT detectors is directly related to the charge collection ability which can be affected by the configuration of the electrical contact. The charge collection efficiency is determined in part by the specific geometry of the anode contact which serves as the readout electrode. In this report, contact geometries including single pixel, planar, coplanar, and dual anode will be systematically explored by comparing the performance efficiencies of the detector using both low and high energy gamma rays. To help eliminate the effect of crystal quality variations, the contact geometries were fabricated on the same crystal detector with minimal polishing between contact placements.

Washington, A.; Duff, M.; Teague, L.

2011-06-21T23:59:59.000Z

179

Rheological control on the initial geometry of the Raft River detachment  

Open Energy Info (EERE)

Rheological control on the initial geometry of the Raft River detachment Rheological control on the initial geometry of the Raft River detachment fault and shear zone, western United States Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Rheological control on the initial geometry of the Raft River detachment fault and shear zone, western United States Details Activities (1) Areas (1) Regions (0) Abstract: The strain, exhumation history, and field orientation of a well-exposed shear zone and detachment fault in the Raft River Mountains of northwestern Utah, a Cordilleran metamorphic core complex, have been studied to determine the kinematics of ductile shearing and initial orientations of the shear zone and detachment fault. Mapping and strain and kinematic analysis indicate that the top-to-the-east Raft River shear zone

180

On Dark Energy, Weyl Geometry and Brans-Dicke-Jordan Scalar Field  

E-Print Network (OSTI)

We review firstly why Weyls Geometry, within the context of Friedman-Lemaitre-Robertson-Walker cosmological models, can account for both the origins and the value of the observed vacuum energy density (dark energy). The source of dark energy is just the dilaton-like Jordan-Brans-Dicke scalar field that is required to implement Weyl invariance of the most simple of all possible actions. A nonvanishing value of the vacuum energy density of the order of 10 ?123 M 4 P lanck is derived in agreement with the experimental observations. Next, a Jordan-Brans-Dicke gravity model within the context of ordinary Riemannian geometry, yields also the observed vacuum energy density (cosmological constant) to very high precision. One finds that the temporal flow of the scalar field ?(t) in ordinary Riemannian geometry, from t = 0 to t = to, has the same numerical effects (as far as the vacuum energy density is concerned) as if there were Weyl scalings from the field configuration ?(t), to the constant field configuration ?o, in Weyl geometry. Hence, Weyl scalings in Weyl geometry can recapture the flow of time which is consistent with Segals Conformal Cosmology, in such a fashion that an expanding universe may be visualized as Weyl scalings of a static universe. The main novel result of this work is that one is able to reproduce the observed vacuum energy density to such a degree of precision 10 ?123 M 4 P lanck, while still having a Big-Bang singularity at t = 0 when the vacuum energy density blows up. This temporal flow of the vacuum energy density, from very high values in the past, to very small values today, is not a numerical coincidence but is the signal of an underlying Weyl geometry (conformal invariance) operating in cosmology, combined with the dynamics of a Brans-Dicke-Jordan scalar field.

Carlos Castro

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Three-dimensional geometry of fluvial reservoir sands: steam-drive case study  

Science Conference Proceedings (OSTI)

The three-dimensional geometry of fluvial sands in South Belridge heavy oil field was investigated as part of an Enhanced Oil Recovery study. It was shown that only close-spaced well data are sufficient to define the sand-body geometries and heterogeneities of multichannelled fluvial systems. Reservoir flow-unit patterns cannot necessarily be correctly delineated by isolated vertical sequence analysis. Wireline logs from 19 wells and conventional cores from seven wells in a 10-ac (660 ft x 660 ft) pattern were correlated in detail, using additional input from sedimentology, steam-flow patterns, and reservoir flow-unit continuity.

McPherson, J.G.; Miller, D.D.

1989-03-01T23:59:59.000Z

182

Non-iterative and exact method for constraining particles in a linear geometry  

E-Print Network (OSTI)

We present a practical numerical method for evaluating the Lagrange multipliers necessary for maintaining a constrained linear geometry of particles in dynamical simulations. The method involves no iterations, and is limited in accuracy only by the numerical methods for solving small systems of linear equations. As a result of the non-iterative and exact (within numerical accuracy) nature of the procedure there is no drift in the constrained geometry, and the method is therefore readily applied to molecular dynamics simulations of, e.g., rigid linear molecules or materials of non-spherical grains. We illustrate the approach through implementation in the commonly used second-order velocity explicit Verlet method.

Horacio Tapia-McClung; Niels Grnbech-Jensen

2004-12-21T23:59:59.000Z

183

Effects of Sample Geometry and Loading Rate onTensile Ductility of TRIP800 Steel  

SciTech Connect

The effects of sample geometry and loading rate on the tensile ductility of a commercial grade Transformation Induced Plasticity (TRIP) steel are examined in this paper. Quasistatic tensile tests were performed for the 1.2mm gauge TRIP800 steel sheets with two geometries: sub-sized ASTM E-8 and a custom designed miniature tensile sample. Sample geometry effects on post-uniform elongation are discussed together with other experimental data reported in the open literature. Further discussions on the effects of sample geometry are cast in the context of mesh-size dependent ductility in finite element-based engineering simulations. The quasi-static tensile curve for the miniature sample is then compared with the split Hopkinson bar results at the loading rates of 1700-S-1 and 2650-S-1 with the same sample design. In contrary to the typical strain rate sensitivity results for mild steel where the dynamic strength increase at high strain rate usually occurs at the price of ductility reduction, our results show that the TRIP800 under examination has positive strain rate sensitivity on both strength and ductility. Images of the deformation process captured by high speed camera together with scanning electron microscopy (SEM) near the fracture zone are also used to elucidate the different deformation modes at different loading rates.

Sun, Xin; Soulami, Ayoub; Choi, Kyoo Sil; Guzman, O.; Chen, Weinong W.

2012-04-15T23:59:59.000Z

184

Modeling the compressive deformation of metal micro-textured thermal interface materials using SEM geometry reconstruction  

Science Conference Proceedings (OSTI)

Idealized and simplified geometries are commonly used in finite element models to ease model creation and meshing. However, at smaller length-scales, the influence of geometrical imperfections and defects can significantly affect the accuracy of the ... Keywords: Buckling, Finite element modeling, Metal micro-textured thermal interface materials, Plastic deformation, SEM stereomicroscopy, Surface reconstruction

R. Kempers; P. Ahern; A. J. Robinson; A. M. Lyons

2012-02-01T23:59:59.000Z

185

Compact fluorescent lamp using horizontal and vertical insulating septums and convective venting geometry  

DOE Patents (OSTI)

A novel design is described for a compact fluorescent lamp, including a lamp geometry which will increase light output and efficacy of the lamp in a base down operating position by providing horizontal and vertical insulating septums positioned in the ballast compartment of the lamp to provide a cooler coldspot. Selective convective venting provides additional cooling of the ballast compartment. 9 figs.

Siminovitch, M.

1998-02-10T23:59:59.000Z

186

Proceedings of the Seventh Canadian Conference on Computational Geometry, Laval University, Quebec, August, 1995, pp. 7984.  

E-Print Network (OSTI)

For a number of years, we have worked on a project on finding tight packings of polygonal objects in two dimen computational geometry and mathematical programming to the task of compaction: quickly finding tight packings is very difficult to simulate. Consider the problems of animating the sand in an hourglass or the sand

Milenkovic, Victor

187

Pschl-Teller Hamiltonian: Gazeau-Klauder type coherent states, related statistics and geometry  

E-Print Network (OSTI)

This work mainly addresses a construction of Gazeau-Klauder type coherent states for a P\\"oschl-Teller model. Relevant characteristics are investigated. Induced geometry and statistics are studied. Then the Berezin - Klauder - Toeplitz quantization of the classical phase space observables is presented.

Mahouton Norbert Hounkonnou; Sama Arjika; Ezinvi Balotcha

2013-09-24T23:59:59.000Z

188

Optimization of bead geometry of submerged arc weld using fuzzy based desirability function approach  

Science Conference Proceedings (OSTI)

The present study highlights application of Taguchi's robust design coupled with fuzzy based desirability function approach for optimizing multiple bead geometry parameters of submerged arc weldment. Fuzzy inference system has been adapted to avoid uncertainly, ... Keywords: Desirability function, Fuzzy logic, SAW, Taguchi's robust design

Ankita Singh; Saurav Datta; Siba Sankar Mahapatra; Tapan Singha; Gautam Majumdar

2013-02-01T23:59:59.000Z

189

New ring-linear codes from dualization in projective Hjelmslev geometries  

Science Conference Proceedings (OSTI)

In this article, several new constructions for ring-linear codes are given. The class of base rings are the Galois rings of characteristic 4, which include Keywords: 05B25, 51C05, 51E20, 94B05, 94B27, Galois ring, Gray map, Hjelmslev geometry, Homogeneous weight, Kerdock code, Lee weight, Ring-linear code

Michael Kiermaier; Johannes Zwanzger

2013-01-01T23:59:59.000Z

190

Short communication: Estimation of stream channel geometry in Idaho using GIS-derived watershed characteristics  

Science Conference Proceedings (OSTI)

This paper describes estimation of stream channel geometry with multiple regression analysis of GIS-derived watershed characteristics including drainage area, catchment-averaged precipitation, mean watershed slope, elevation, forest cover, percent area ... Keywords: Cross-sections, GIS, Modeling, Stream channels, Streamstats, Watersheds

Daniel P. Ames; Eric B. Rafn; Robert Van Kirk; Benjamin Crosby

2009-03-01T23:59:59.000Z

191

Correspondence of phase transition points and singularities of thermodynamic geometry of black holes  

E-Print Network (OSTI)

We explore a formulation of thermodynamic geometry of black holes and prove that the divergent points of the specific heat correspond exactly to the singularities of the thermodynamic curvature. We investigate this correspondence for different types of black holes. This formulation can also be applied to an arbitrary thermodynamic system.

Mansoori, Seyed Ali Hosseini

2013-01-01T23:59:59.000Z

192

The standing wave FEL/TBA: Realistic cavity geometry and energy extraction  

SciTech Connect

A set of parameters for standing wave free electron laser two beam accelerators (SWFEL/TBA) is evaluated for realistic cavity geometry taking into account beam-break-up and the sensitivity of output power to imperfections. Also given is a power extraction system using cavity coupled wave guides.

Kim, Jin-Soo, Henke, H.; Sessler, A.M.; Sharp, W.M.

1993-05-01T23:59:59.000Z

193

Neutron Noise Calculations in Hexagonal Geometry and Comparison with Analytical Solutions  

E-Print Network (OSTI)

Division of Nuclear Engineering, SE-412 96 Göteborg, Sweden Received June 6, 2012 Accepted January 9, 2013- culations in hexagonal geometries. The tool is developed based on diffusion theory with multienergy groups technique was considered early as a powerful technique in reactor diagnostics and core monitoring.1

Demazière, Christophe

194

Virtual prototyping of automated manufacturing systems with Geometry-driven Petri nets  

Science Conference Proceedings (OSTI)

The design process of automated manufacturing systems typically involves physical prototypes to validate the interactions between hardware and software components. However, physical prototyping is expensive and time consuming, which often leads to insufficient ... Keywords: Early testing, Geometry-driven Petri nets, Robotic systems, Simulation, Virtual prototyping

Jens H. Weber-Jahnke; Jochen Stier

2009-12-01T23:59:59.000Z

195

Compact formulas for guiding-center orbits in axisymmetric tokamak geometry  

Science Conference Proceedings (OSTI)

Compact formulas for trapped-particle and passing-particle guiding-center orbits in axisymmetric tokamak geometry are given in terms of the Jacobi elliptic functions and complete elliptic integrals. These formulas can find applications in bounce-center kinetic theory as well as guiding-center Fokker-Planck kinetic theory.

Brizard, Alain J. [Department of Chemistry and Physics, Saint Michael's College Colchester, Vermont 05439 (United States)

2011-02-15T23:59:59.000Z

196

Design explorations of performance driven geometry in architectural design using parametric modeling and genetic algorithms  

Science Conference Proceedings (OSTI)

In this paper we discuss the benefits derived by combining parametric modeling and genetic algorithms to achieve a performance oriented process in design, with specific focus on architectural design. The key role played by geometry in architecture is ... Keywords: Exploration, Genetic algorithms, Integrated design, Optimization, Parametric modeling, Performance oriented design

Michela Turrin; Peter von Buelow; Rudi Stouffs

2011-10-01T23:59:59.000Z

197

On Symmetry and Multiple-View Geometry: Structure, Pose, and Calibration from a Single Image  

Science Conference Proceedings (OSTI)

In this paper, we provide a principled explanation of how knowledge in global 3-D structural invariants, typically captured by a group action on a symmetric structure, can dramatically facilitate the task of reconstructing a 3-D scene from one or more ... Keywords: multiple-view geometry, reflective symmetry, rotational symmetry, structure from symmetry, symmetry group, translational symmetry

Wei Hong; Allen Yang Yang; Kun Huang; Yi Ma

2004-12-01T23:59:59.000Z

198

Conical geometry for sagittal focusing as applied to X rays from synchrotrons  

SciTech Connect

The authors describe a method for simultaneously focusing and monochromatization of X rays from a fan of radiation having up to 15 mrad divergence in one dimension. This geometry is well suited to synchrotron radiation sources at magnifications of one-fifth to two and is efficient for X-ray energies between 3 and 40 keV (0.48 and 6.4 fJ). The method uses crystals bent to part of a cone for sagittal focusing and allows for the collection of a larger divergence with less mixing of the horizontal into the vertical divergence than is possible with X-ray mirrors. They describe the geometry required to achieve the highest efficiency when a conical crystal follows a flat crystal in a nondispersive two-crystal monochromator. At a magnification of one-third, the geometry is identical to a cylindrical focusing design described previously. A simple theoretical calculation is shown to agree well with ray-tracing results. Minimum aberrations are observed at magnifications near one. Applications of the conical focusing geometry to existing and future synchrotron radiation facilities are discussed.

Ice, G.E.; Sparks, C.J.

1993-06-01T23:59:59.000Z

199

Compact fluorescent lamp using horizontal and vertical insulating septums and convective venting geometry  

SciTech Connect

A novel design for a compact fluorescent lamp, including a lamp geometry which will increase light output and efficacy of the lamp in a base down operating position by providing horizontal and vertical insulating septums positioned in the ballast compartment of the lamp to provide a cooler coldspot. Selective convective venting provides additional cooling of the ballast compartment.

Siminovitch, Michael (El Sobrante, CA)

1998-01-01T23:59:59.000Z

200

On the nonexistence of a Lobachevsky geometry model of an isotropic and homogeneous universe  

Science Conference Proceedings (OSTI)

According to the Einstein cosmological principle, our universe is homogeneous and isotropic, i.e. its curvature is constant at any point and in any direction. On large scales, when all local irregularities are ignored, this assumption has been confirmed ... Keywords: Gauss-Kronecker curvature, Lobachevsky and Riemannian geometry, geometric cosmology, manifolds, modelling, umbilic points

Michal K?ek; Jana Pradlov

2003-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Improvement of PNP Problem Computational Efficiency For Known Target Geometry of Cubesats  

E-Print Network (OSTI)

This thesis considers the Perspective-N-Point (PNP) problem with orthogonal target geometry, as seen in the problem of cubesat relative navigation. Cubesats are small spacecraft often developed for research purposes and to perform missions in space at low cost. Sensor systems for cubesats have been designed that, by providing vector (equivalently line-of-sight, angle, and image plane) measurements, equate relative navigation to a PNP problem. Much study has been done on this problem, but little of it has considered the case where target geometry is known in advance, as is the case with cooperating cubesats. A typical constraint for cubesats, as well as other PNP applications, is processing resources. Therefore, we considered the ability to reduce processing burden of the PNP solution by taking advantage of the known target geometry. We did this by considering a specific P3P solver and a specific point-cloud correspondence (PCC) solver for disambiguating/improving the estimate, and modifying them both to take into account a known orthogonal geometry. The P3P solver was the Kneip solver, and the point-cloud-correspondence solver was the Optimal Linear Attitude Estimator (OLAE). We were able to achieve over 40% reduction in the computational time of the P3P solver, and around 10% for the PCC solver, vs. the unmodified solvers acting on the same problems. It is possible that the Kneip P3P solver was particularly well suited to this approach. Nevertheless, these findings suggest similar investigation may be worthwhile for other PNP solvers, if (1) processing resources are scarce, and (2) target geometry can be known in advance.

Hafer, William

2012-05-01T23:59:59.000Z

202

A robust geometry estimation method for spiral, sequential and circular cone-beam micro-CT  

Science Conference Proceedings (OSTI)

Purpose: The authors propose a novel method for misalignment estimation of micro-CT scanners using an adaptive genetic algorithm. Methods: The proposed algorithm is able to estimate the rotational geometry, the direction vector of table movement and the displacement between different imaging threads of a dual source or even multisource scanner. The calibration procedure does not rely on dedicated calibration phantoms and a sequence scan of a single metal bead is sufficient to geometrically calibrate the whole imaging system for spiral, sequential, and circular scan protocols. Dual source spiral and sequential scan protocols in micro-computed tomography result in projection data that-besides the source and detector positions and orientations-also require a precise knowledge of the table direction vector to be reconstructed properly. If those geometric parameters are not known accurately severe artifacts and a loss in spatial resolution appear in the reconstructed images as long as no geometry calibration is performed. The table direction vector is further required to ensure that consecutive volumes of a sequence scan can be stitched together and to allow the reconstruction of spiral data at all. Results: The algorithm's performance is evaluated using simulations of a micro-CT system with known geometry and misalignment. To assess the quality of the algorithm in a real world scenario the calibration of a micro-CT scanner is performed and several reconstructions with and without geometry estimation are presented. Conclusions: The results indicate that the algorithm successfully estimates all geometry parameters, misalignment artifacts in the reconstructed volumes vanish, and the spatial resolution is increased as can be shown by the evaluation of modulation transfer function measurements.

Sawall, Stefan; Knaup, Michael; Kachelriess, Marc [Institute of Medical Physics (IMP), University of Erlangen-Nuernberg, 91052 Erlangen (Germany); Institute of Medical Physics (IMP), University of Erlangen-Nuernberg, 91052 Erlangen (Germany) and Medical Physics in Radiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany)

2012-09-15T23:59:59.000Z

203

Controlling acid rain  

E-Print Network (OSTI)

High concentrations of sulfuric and nitric acid in raTn fn the northeastern USA are caused by the large scale combustion of fossil fuels within this region. Average precipitation acidity is pH 4.2, but spatial and temporal ...

Fay, James A.

1983-01-01T23:59:59.000Z

204

On the Distributional Nature of the Energy Momentum Tensor of a Black Hole or What Curves the Schwarzschild Geometry ?  

E-Print Network (OSTI)

Using distributional techniques we calculate the energy--momentum tensor of the Schwarzschild geometry. It turns out to be a well--defined tensor--distribution concentrated on the $r=0$ region which is usually excluded from space--time. This provides a physical interpretation for the curvature of this geometry.

Herbert Balasin; Herbert Nachbagauer

1993-05-10T23:59:59.000Z

205

A cell-centered Lagrangian finite volume approach for computing elasto-plastic response of solids in cylindrical axisymmetric geometries  

Science Conference Proceedings (OSTI)

A finite volume cell-centered Lagrangian formulation is presented for solving large deformation problems in cylindrical axisymmetric geometries. Since solid materials can sustain significant shear deformation, evolution equations for stress and strain ... Keywords: Axisymmetric geometries, Cell-centered, Elasto-plastic, Finite volume, Hydrodynamics, Hypo-elastic, Lagrangian, Material strength, Mimetic, Solid mechanics

Shiv Kumar Sambasivan; Mikhail J. Shashkov; Donald E. Burton

2013-03-01T23:59:59.000Z

206

Turbulent Flow Analysis and Coherent Structure Identification in Experimental Models with Complex Geometries  

E-Print Network (OSTI)

Turbulent flows and coherent structures emerging within turbulent flow fields have been extensively studied for the past few decades and a wide variety of experimental and numerical techniques have been developed for measurement and analysis of turbulent flows. The complex nature of turbulence requires methods that can accurately estimate its highly chaotic spatial and temporal behavior. Some of the classical cases of turbulent flows with simpler geometries have been well characterized by means of the existing experimental techniques and numerical models. Nevertheless, since most turbulent fields are of complex geometries; there is an increasing interest in the study of turbulent flows through models with more complicated geometries. In this dissertation, characteristics of turbulent flows through two different facilities with complex geometries are studied applying two different experimental methods. The first study involves the investigation of turbulent impinging jets through a staggered array of rods with or without crossflow. Such flows are crucial in various engineering disciplines. This experiment aimed at modeling the coolant flow behavior and mixing phenomena within the lower plenum of a Very High Temperature Reactor (VHTR). Dynamic Particle Image Velocimetry (PIV) and Matched Index of Refraction (MIR) techniques were applied to acquire the turbulent velocity fields within the model. Some key flow features that may significantly enhance the flow mixing within the test section or actively affect some of the structural components were identified in the velocity fields. The evolution of coherent structures within the flow field is further investigated using a Snapshot Proper Orthogonal Decomposition (POD) technique. Furthermore, a comparative POD method is proposed and successfully implemented for identification of the smaller but highly influential coherent structures which may not be captured in the full-field POD analysis. The second experimental study portrays the coolant flow through the core of an annular pebble bed VHTR. The complex geometry of the core and the highly turbulent nature of the coolant flow passing through the gaps of fuel pebbles make this case quite challenging. In this experiment, a high frequency Hot Wire Anemometry (HWA) system is applied for velocity measurements and investigation of the bypass flow phenomena within the near wall gaps of the core. The velocity profiles within the gaps verify the presence of an area of increased velocity close to the outer reflector wall; however, the characteristics of the coolant flow profile is highly dependent on the gap geometry and to a less extent on the Reynolds number of the flow. The time histories of the velocity are further analyzed using a Power Spectra Density (PSD) technique to acquire information about the energy content and energy transfer between eddies of different sizes at each point within the gaps.

Amini, Noushin

2011-12-01T23:59:59.000Z

207

Synthesis of acid addition salt of delta-aminolevulinic acid ...  

A process of preparing an acid addition salt of delta-aminolevulinc acid comprising: a) dissolving a lower alkyl 5-bromolevulinate and hexamethylenetetramine in a ...

208

Recovery of Phosphoric Acid in Waste Acid Mixtures Discharged ...  

Science Conference Proceedings (OSTI)

Aug 1, 2003 ... In order to separate impurity acids from the phosphoric acid, trioctyl phosphate ( TOP) is used as an extractant. TOP can extract acetic and nitric...

209

Minimal Curvature Trajectories: Riemannian Geometry Concepts for Model Reduction in Chemical Kinetics  

E-Print Network (OSTI)

In dissipative ordinary differential equation systems different time scales cause anisotropic phase volume contraction along solution trajectories. Model reduction methods exploit this for simplifying chemical kinetics via a time scale separation into fast and slow modes. The aim is to approximate the system dynamics with a dimension-reduced model after eliminating the fast modes by enslaving them to the slow ones via computation of a slow attracting manifold. We present a novel method for computing approximations of such manifolds using trajectory-based optimization. We discuss Riemannian geometry concepts as a basis for suitable optimization criteria characterizing trajectories near slow attracting manifolds and thus provide insight into fundamental geometric properties of multiple time scale chemical kinetics. The optimization criteria correspond to a suitable mathematical formulation of "minimal relaxation" of chemical forces along reaction trajectories under given constraints. We present various geometri...

Lebiedz, Dirk; Siehr, Jochen

2009-01-01T23:59:59.000Z

210

Cumulus Geometry from Satellite and Surface Data at the ARM TWP Site  

NLE Websites -- All DOE Office Websites (Extended Search)

Cumulus Geometry from Satellite and Surface Data Cumulus Geometry from Satellite and Surface Data at the ARM TWP Site E. I. Kassianov, T. P. Ackerman, and R. T. Marchand Pacific Northwest National Laboratory Richland, Washington Introduction The multi-angle imaging spectrometer (MISR), a sensor on board the earth observing system (EOS) Terra satellite platform, observes reflected radiation in nine directions with high resolution (~0.275 km). The overall mission of the MISR is to provide continuous, global multi-angle measurements of the reflected radiation from the earth's atmosphere and surface, and thereby create a valuable resource for studying their physical properties (Diner et al. 1999). For single-layer marine cumulus clouds, we have demonstrated that satellite-derived basic statistics (mean, variance) of vertical cloud size match closely

211

Large-eddy simulations of Richtmyer-Meshkov instability in a converging geometry  

E-Print Network (OSTI)

The Richtmyer-Meshkov instability (RMI) refers to the baroclinic generation of vorticity at a perturbed density interface when impacted by a shock wave. It is often thought of as the impulsive limit of the Rayleigh-Taylor instability (RTI). The fluid dynamics video "large-eddy simulations (LES) of RMI in a converging geometry" shows the mixing of materials resulting from the interaction of an imploding cylindrical shock wave with a concentric perturbed interface that separates outside light gas from heavy gas (initially 5 times denser) inside a wedge. At the initial impact, the incident shock Mach number is either 1.3 or 2.0. The present canonical simulations support recent interests on compressible turbulent mixing in converging geometries relevant to both inertial confinement fusion and core-collapse supernovae dynamics.

Lombardini, Manuel

2009-01-01T23:59:59.000Z

212

Effects of Nanoparticle Geometry and Size Distribution on Diffusion Impedance of Battery Electrodes  

E-Print Network (OSTI)

The short diffusion lengths in insertion battery nanoparticles render the capacitive behavior of bounded diffusion, which is rarely observable with conventional larger particles, now accessible to impedance measurements. Coupled with improved geometrical characterization, this presents an opportunity to measure solid diffusion more accurately than the traditional approach of fitting Warburg circuit elements, by properly taking into account the particle geometry and size distribution. We revisit bounded diffusion impedance models and incorporate them into an overall impedance model for different electrode configurations. The theoretical models are then applied to experimental data of a silicon nanowire electrode to show the effects of including the actual nanowire geometry and radius distribution in interpreting the impedance data. From these results, we show that it is essential to account for the particle shape and size distribution to correctly interpret impedance data for battery electrodes. Conversely, it...

Song, J

2012-01-01T23:59:59.000Z

213

Variable-geometry turbocharger with asymmetric divided volute for engine exhaust gas pulse optimization  

DOE Patents (OSTI)

A turbine assembly for a variable-geometry turbocharger includes a turbine housing defining a divided volute having first and second scrolls, wherein the first scroll has a substantially smaller volume than the second scroll. The first scroll feeds exhaust gas to a first portion of a turbine wheel upstream of the throat of the wheel, while the second scroll feeds gas to a second portion of the wheel at least part of which is downstream of the throat. Flow from the second scroll is regulated by a sliding piston. The first scroll can be optimized for low-flow conditions such that the turbocharger can operate effectively like a small fixed-geometry turbocharger when the piston is closed. The turbine housing defines an inlet that is divided by a dividing wall into two portions respectively feeding gas to the two scrolls, a leading edge of the dividing wall being downstream of the inlet mouth.

Serres, Nicolas (Epinal, FR)

2010-11-09T23:59:59.000Z

214

Geometry and heterogeneous effects on the neutronic performance of a Yin Yang mirror-reactor blanket  

SciTech Connect

From 5th symposium on engineering problems of fusion research; Princeton, New Jersey, USA (6 Nov 1973). Two-dimensional models and Monte Carlo neutron transport techniques were used to calculate the tritium breeding and energy generation in a mirror-reactor blanket. Results indicate that blanket performance should be quite insensitive to variations in overall geometry as long as there are no large neutron-leakage paths. Injection and leakage penetration can be accommodated as long as the first-wall peneiration area subtends less than 25% of the first wall's spherical area. Heterogeneous and streaming effects in a tubular blanket can be important, but are negligible for closely packed arrays of tubes. The one-dimensional homogeneous spherical-shell model appears to be a useful tool for predicting performance of a tubular blanket conforming to the YinYang mirror geometry. (auth)

Lee, J.D.

1973-10-17T23:59:59.000Z

215

Mbius Transformation and Einsten Velocity Addition in the Hyperbolic Geometry of Bolyai and Lobachevsky  

E-Print Network (OSTI)

In this chapter, dedicated to the 60th Anniversary of Themistocles M. Rassias, M\\"obius transformation and Einstein velocity addition meet in the hyperbolic geometry of Bolyai and Lobachevsky. It turns out that M\\"obius addition that is extracted from M\\"obius transformation of the complex disc and Einstein addition from his special theory of relativity are isomorphic in the sense of gyrovector spaces.

Abraham A. Ungar

2013-03-19T23:59:59.000Z

216

Plasma response to symmetry breaking perturbations in the reversed field geometry  

SciTech Connect

Field reversal does not insure closure of the reversed field geometry. The closure is critically dependent on the shape of the toroidal field B/sub 1/ Vector. The plasma diamagnetic currents are shown to establish a spacial scale for the field B/sub 1/ Vector which is lambda approximately equal to a/..sqrt beta../sub 1/ with a the plasma radius and ..beta../sub 1/ the plasma beta relative to the B/sub 1/ Vector field.

Boozer, A.H.

1978-02-01T23:59:59.000Z

217

Influence of p-method finite element parameters on predictions of crack front geometry  

Science Conference Proceedings (OSTI)

The effect of various p-method finite element model parameters on the prediction of planar crack front geometry in three dimensional structures is evaluated. An automatic crack growth method was developed using the commercial software StressCheck coupled ... Keywords: ?, Corner crack, Crack front, Finite element, Mesh, Stress intensity factor, a, b, b/a, c, ctrat, ipr, m, mrat, p-method, trans

Diane Wowk, Kyle Gamble, Ross Underhill

2013-10-01T23:59:59.000Z

218

An improved known vicinity algorithm based on geometry test for particle localization in arbitrary grid  

Science Conference Proceedings (OSTI)

The known vicinity algorithm based on the geometry test for the particle localization problem in the hybrid Eulerian-Lagrangian model was extended and enhanced aiming at the connected grids with convex polygon/polyhedral cells. Such extensions were achieved ... Keywords: 47.55.Ca, 47.55.Kf, 65K10, 76M28, 76T10, Binary search, Eulerian-Lagrangian simulation, Known vicinity algorithm, Particle localization, Unstructured grid

Peng Ke; Shuguang Zhang; Jianghao Wu; Chunxin Yang

2009-12-01T23:59:59.000Z

219

KENO3D Visualization Tool for KENO V.a and KENO-VI Geometry Models  

SciTech Connect

Criticality safety analyses often require detailed modeling of complex geometries. Effective visualization tools can enhance checking the accuracy of these models. This report describes the KENO3D visualization tool developed at the Oak Ridge National Laboratory (ORNL) to provide visualization of KENO V.a and KENO-VI criticality safety models. The development of KENO3D is part of the current efforts to enhance the SCALE (Standardized Computer Analyses for Licensing Evaluations) computer software system.

Horwedel, J.E.; Bowman, S.M.

2000-06-01T23:59:59.000Z

220

Homogenization of a catalyst layer model for periodically distributed pore geometries in PEM fuel cells  

E-Print Network (OSTI)

We formally derive an effective catalyst layer model comprising the reduction of oxygen for periodically distributed pore geometries. By assumption, the pores are completely filled with water and the surrounding walls consist of catalyst particles which are attached to an electron conducting microstructure. The macroscopic transport equations are established by a multi-scale approach, based on microscopic phenomena at the pore level, and serve as a first step toward future optimization of catalyst layer designs.

Schmuck, Markus

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Homogenization of a catalyst layer model for periodically distributed pore geometries in PEM fuel cells  

E-Print Network (OSTI)

We formally derive an effective catalyst layer model comprising the reduction of oxygen for periodically distributed pore geometries. By assumption, the pores are completely filled with water and the surrounding walls consist of catalyst particles which are attached to an electron conducting microstructure. The macroscopic transport equations are established by a multi-scale approach, based on microscopic phenomena at the pore level, and serve as a first step toward future optimization of catalyst layer designs.

Markus Schmuck; Peter Berg

2012-04-30T23:59:59.000Z

222

Reactivity of Acid Generators  

NLE Websites -- All DOE Office Websites (Extended Search)

Reactivity of Acid Generators for Chemically Amplified Resists with Reactivity of Acid Generators for Chemically Amplified Resists with Low-Energy Electrons Atsuro Nakano, Takahiro Kozawa, Seiichi Tagawa, Tomasz Szreder, James F. Wishart, Toshiyuki Kai and Tsutomu Shimokawa Jpn. J. Appl. Phys., 45, L197-L200 (2006). [Find paper at the Japanese Journal of Applied Physics] Abstract: In chemically amplified resists for ionizing radiations such as electron beams and extreme ultraviolet (EUV), low-energy electrons play an important role in the pattern formation processes. The reactivity of acid generators with low-energy electrons was evaluated using solvated electrons in tetrahydrofuran, which were generated by a pulsed electron beam. The rate constants of acid generators with the solvated electrons ranged from 0.6 to 1.9 x 1011 M-1s-1

223

Chlorophyll and acid rain  

NLE Websites -- All DOE Office Websites (Extended Search)

Chlorophyll and acid rain Chlorophyll and acid rain Name: beachbum Status: N/A Age: N/A Location: N/A Country: N/A Date: Around 1993 Question: A while ago I read an article that stated that after a plant received acid rain, there seemed to be less of chlorophyll a and b in the plant. I was wondering where does the chlorophyll go and what is the actual process (cell structure affected?). Replies: I think that less chlorophyll being present would be more likely a result of less being produced. Plant cell constantly turn over cell material, it will also constantly produce more. So if one compares a plant not exposed to acid rain (presumably producing a normal amount of chlorophyll and the exposed plant then one sees that the exposed plant has less chlorophyll than the unexposed plant. I do not think I can answer the rest of your question.

224

(Acid rain workshop)  

SciTech Connect

The traveler presented a paper entitled Susceptibility of Asian Ecosystems to Soil-Mediated Acid Rain Damage'' at the Second Workshop on Acid Rain in Asia. The workshop was organized by the Asian Institute of Technology (Bangkok, Thailand), Argonne National Laboratory (Argonne, Illinois), and Resource Management Associates (Madison, Wisconsin) and was sponsored by the US Department of Energy, the United Nations Environment Program, the United Nations Economic and Social Commission for Asia and the Pacific, and the World Bank. Papers presented on the first day discussed how the experience gained with acid rain in North America and Europe might be applied to the Asian situation. Papers describing energy use projections, sulfur emissions, and effects of acid rain in several Asian countries were presented on the second day. The remaining time was allotted to discussion, planning, and writing plans for a future research program.

Turner, R.S.

1990-12-05T23:59:59.000Z

225

THREE-DIMENSIONAL EXPLOSION GEOMETRY OF STRIPPED-ENVELOPE CORE-COLLAPSE SUPERNOVAE. I. SPECTROPOLARIMETRIC OBSERVATIONS  

Science Conference Proceedings (OSTI)

We study the multi-dimensional geometry of supernova (SN) explosions by means of spectropolarimetric observations of stripped-envelope SNe, i.e., SNe without a hydrogen-rich layer. We perform spectropolarimetric observations of two stripped-envelope SNe, Type Ib SN 2009jf and Type Ic SN 2009mi. Both objects show non-zero polarization at the wavelength of the strong lines. They also show a loop in the Stokes Q - U diagram, which indicates a non-axisymmetric, three-dimensional ion distribution in the ejecta. We show that five out of six stripped-envelope SNe, which have been observed spectropolarimetrically so far, show such a loop. This implies that a three-dimensional geometry is common in stripped-envelope SNe. We find that stronger lines tend to show higher polarization. This effect is not related to the geometry, and must be corrected for to compare the polarization of different lines or different objects. Even after the correction, however, there remains a dispersion of polarization degree among different objects. Such a dispersion might be caused by three-dimensional clumpy ion distributions viewed from different directions.

Tanaka, Masaomi; Iye, Masanori [National Astronomical Observatory, Mitaka, Tokyo (Japan); Kawabata, Koji S.; Yamanaka, Masayuki [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima (Japan); Hattori, Takashi; Aoki, Kentaro; Sasaki, Toshiyuki [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); Mazzali, Paolo A. [Max-Planck Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 2 D-85748 Garching bei Muenchen (Germany); Maeda, Keiichi; Nomoto, Ken'ichi [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa (Japan); Pian, Elena, E-mail: masaomi.tanaka@nao.ac.jp [Istituto Naz. di Astrofisica-Oss. Astron., Via Tiepolo, 11, 34131 Trieste (Italy)

2012-07-20T23:59:59.000Z

226

New gravity-capillary waves at low speeds. Part 2: Nonlinear geometries  

E-Print Network (OSTI)

When traditional linearised theory is used to study gravity-capillary waves produced by flow past an obstruction, the geometry of the object is assumed to be small in one or several of its dimensions. In order to preserve the nonlinear nature of the obstruction, asymptotic expansions in the low-Froude or low-Bond number limits can be derived, but here, the solutions are waveless to every order. This is because the waves are in fact, exponentially small, and thus beyond-all-orders of regular asymptotics; their formation is a consequence of the divergence of the asymptotic series and the associated Stokes Phenomenon. In Part 1, we showed how exponential asymptotics could be used to study the problem when the size of the obstruction is first linearised. In this paper, we extend the analysis to the nonlinear problem, thus allowing the full geometry to be considered at leading order. When applied to the classic problem of flow over a step, our analysis reveals the existence of six classes of gravity-capillary waves, from which two share a connection with the usual linearised solutions first discovered by Lord Rayleigh. The new solutions arise due to the availability of multiple singularities in the geometry, coupled with the interplay of gravitational and cohesive effects.

Philippe H. Trinh; S. Jonathan Chapman

2013-04-23T23:59:59.000Z

227

The iBP algorithm for the discretizable molecular distance geometry ...  

E-Print Network (OSTI)

Jan 6, 2011 ... wireless sensors given some of the distances (estimated by monitoring the ..... this operation for all the amino acids forming a protein, then the...

228

Effects of Combustor Geometry on the Flowfields and Flame Properties of A  

NLE Websites -- All DOE Office Websites (Extended Search)

Effects of Combustor Geometry on the Flowfields and Flame Properties of A Effects of Combustor Geometry on the Flowfields and Flame Properties of A Low-Swirl Injector Title Effects of Combustor Geometry on the Flowfields and Flame Properties of A Low-Swirl Injector Publication Type Journal Article Year of Publication 2008 Authors Cheng, Robert K., and David Littlejohn Journal Proceedings of the Combustion Institute Type of Article Conference Paper Abstract The Low-swirl injector (LSI) is a novel dry-low NOx combustion method that is being developed for gas turbines to burn a variety of gaseous fuels including natural gas, low-Btu fuels, syngases and hydrogen. Its basic principle is described by a top level analytical model that relates the flame position to the flowfield similarity parameters and the turbulent flame speed correlation. The model was based on experimental measurements in open laboratory flames. It has been useful for guiding hardware development. As the LSI is being adapted to different engine configurations, one open question is how the combustor geometry and size affect its basic operating principle. The objective of this paper is to investigate these effects by conducting Particle Image Velocimetry (PIV) measurements in open and enclosed flames produced by a 6.35 cm diameter LSI using two quartz cylinders of 15.5 and 20 cm diameter to simulate the combustor casing. Results from 18 methane-air flames show that the enclosures do not alter the flame properties or the nearfield flow structures. The differences occur mostly in the farfield where the tighter enclosure deters the formation of a weak recirculation zone. The enclosure effects on hydrogen and hydrogen-methane flames were studies using the 20 cm cylinder. The results show that the outer recirculation zone generated at the corner of the dump plane promotes the formation of attached flames. However, the properties and nearfield flow features of the attached flames are similar to those of the lifted flames. At higher stoichiometries, the attached flame collapses to form a compact disc shaped flame that has very different flowfield structures. These results show that the enclosure effects on the LSI are strongly coupled to the fuel type and dump plane geometry but are less dependent on the enclosure size. These observations will provide the basis for developing computational methods that can be used as design tools for LSI adaptation

229

Role of Transport Phenomena in the Evolution of Geometry, Composition and Structure  

SciTech Connect

Abstract Fusion welding is used extensively in industries that support the nation's energy supply, defense, infrastructure, and standard of living. Safety and reliability of the welded joints are affected by their geometry, composition and structure. This report provides an account of the significant advances made in quantitative understanding of the geometry, composition and various aspects of the weldment structure with financial support from DOE/BES. In particular, this report provides an account of the research conducted under the grant DE-FG02-84ER45158 in this important area and lists all the publications that document the details of the technical accomplishments that resulted from the work. Investigations of heat transfer, fluid flow and alloying element vaporization during laser welding resulted in a new technique for the determination of the peak temperature in the weld pool and provided a new method to estimate weld metal composition. Studies on the interfacial phenomena in fusion welding resulted in quantitative understanding of the interrelationship between the weld metal composition and geometry and provided new knowledge as to when the surface active elements would affect the weldment geometry and when these elements would have no effect on the geometry. Partitioning of oxygen nitrogen and hydrogen between the welding environment and the weld metal was affected by the extent of the dissociation of diatomic gaseous species which depended on the nature of the plasma formed during welding. The interfacial tension of the liquid metal was also affected by the plasma and the properties of the plasma affected the concentrations of oxygen, nitrogen and hydrogen in the weld metal. Apart from the understanding of the evolution of composition and geometry of the weldments, application of transport phenomena provided useful information about various features of the weldment structure. Quantitative understanding of microstructure of the fusion zone and heat affected zone and grain structure in both steels and titanium alloys could be achieved starting with numerical heat transfer and fluid flow calculations. In addition, the evolution of inclusion composition and structure in steels during welding could also be understood from fundamental principles. The positions of the students supported by the grant are indicated since an important component of the work was the education of many outstanding students who now occupy leadership positions in major organizations in the US. The research sponsored by the Basic Energy Sciences has been recognized by many major scholastic awards. These are listed because they testify to the quality of the curiosity and the commitment of the students that were supported by the grant. Our collaborations with Oak Ridge National Laboratory, Lawrence Livermore National Laboratory and Sandia National Laboratory are indicated because many outstanding scientists from these laboratories shared our goals in advancing quantitative understanding of fusion welding processes and the geometry, composition and structure of welded materials.

Tarasankar DebRoy

2005-11-17T23:59:59.000Z

230

Optical high acidity sensor  

DOE Patents (OSTI)

An apparatus and method for determining acid concentrations in solutions having acid concentrations of from about 0.1 Molar to about 16 Molar is disclosed. The apparatus includes a chamber for interrogation of the sample solution, a fiber optic light source for passing light transversely through the chamber, a fiber optic collector for receiving the collimated light after transmission through the chamber, a coating of an acid resistant polymeric composition upon at least one fiber end or lens, the polymeric composition in contact with the sample solution within the chamber and having a detectable response to acid concentrations within the range of from about 0.1 Molar to about 16 Molar, a measurer for the response of the polymeric composition in contact with the sample solution, and a comparer of the measured response to predetermined standards whereby the acid molarity of the sample solution within the chamber can be determined. Preferably, a first lens is attached to the end of the fiber optic light source, the first lens adapted to collimate light from the fiber optic light source, and a second lens is attached to the end of the fiber optic collector for focusing the collimated light after transmission through the chamber. 10 figs.

Jorgensen, B.S.; Nekimken, H.L.; Carey, W.P.; O`Rourke, P.E.

1997-07-22T23:59:59.000Z

231

Optical high acidity sensor  

DOE Patents (OSTI)

An apparatus and method for determining acid concentrations in solutions having acid concentrations of from about 0.1 Molar to about 16 Molar is disclosed. The apparatus includes a chamber for interrogation of the sample solution, a fiber optic light source for passing light transversely through the chamber, a fiber optic collector for receiving the collimated light after transmission through the chamber, a coating of an acid resistant polymeric composition upon at least one fiber end or lens, the polymeric composition in contact with the sample solution within the chamber and having a detectable response to acid concentrations within the range of from about 0.1 Molar to about 16 Molar, a measurer for the response of the polymeric composition in contact with the sample solution, and, a comparer of the measured response to predetermined standards whereby the acid molarity of the sample solution within the chamber can be determined. Preferably, a first lens is attached to the end of the fiber optic light source, the first lens adapted to collimate light from the fiber optic light source, and a second lens is attached to the end of the fiber optic collector for focusing the collimated light after transmission through the chamber.

Jorgensen, Betty S. (Jemez Springs, NM); Nekimken, Howard L. (Los Alamos, NM); Carey, W. Patrick (Lynnwood, WA); O' Rourke, Patrick E. (Martinez, GA)

1997-01-01T23:59:59.000Z

232

Nucleic Acid Tools  

NLE Websites -- All DOE Office Websites (Extended Search)

Nucleic Acid Tools Nucleic Acid Tools RNA 3D Motif Atlas, a representative collection of RNA 3D internal and hairpin loop motifs. Petrov, A.I., Zirbel, C.L., Leontis, N.B. (2013) Automated classification of RNA 3D motifs and the RNA 3D motif atlas. RNA. Non-redundant List of RNA-containing 3D structures. Leontis, N.B., & Zirbel, C.L. (2012) In Leontis, N. B., Westhof. E. (ed.), RNA 3D structure analysis and prediction. Springer Berlin Heidelberg Vol. 27, pp. 281-298. RNA Base Triple Atlas, a collection of motifs consisting of two RNA basepairs. Abu Almakarem, A.S., Petrov, A.I., Stombaugh, J., Zirbel, C.L. and Leontis, N.B. (2012) Comprehensive survey and geometric classification of base triples in RNA structures. Nucleic Acids Res, 40, 1407-1423. R3D Align, an application for detailed nucleotide to nucleotide

233

Interaction of Nocturnal Low-Level Jets with Urban Geometries as Seen in Joint Urban 2003 Data  

Science Conference Proceedings (OSTI)

Because accurate modeling of atmospheric flows in urban environments requires sophisticated representation of complex urban geometries, much work has been devoted to treatment of the urban surface. However, the importance of the larger-scale flow ...

Julie K. Lundquist; Jeffrey D. Mirocha

2008-01-01T23:59:59.000Z

234

Fluctuating surface currents: An algorithm for efficient prediction of Casimir interactions among arbitrary materials in arbitrary geometries  

E-Print Network (OSTI)

This paper presents a method for the efficient numerical computation of Casimir interactions between objects of arbitrary geometries, composed of materials with arbitrary frequency-dependent electrical properties. Our ...

Reid, M. T. Homer

235

Cluster catalyzed chemisorption of H2 on Si(111)(11): Effects of collision speed and cluster geometry  

Science Conference Proceedings (OSTI)

We have carried out classical dynamical simulations of collisions of Ar12H2clusters with a rigid Si(111)(11) solid surface for a variety of collision speeds and two different cluster geometries. At low cluster temperatures

John N. Beauregard; Howard R. Mayne

1993-01-01T23:59:59.000Z

236

The effects of geometry and adjacent regenerators on shell-and-tube heat exchangers in oscillating flows.  

E-Print Network (OSTI)

??An experimental study into the effects of geometry and the presence of adjacent screens on the acoustic impedances and heat transfer performance of shell-and-tube heat (more)

Brady, John

2010-01-01T23:59:59.000Z

237

Mesoscopic model for filament orientation in growing actin networks: the role of obstacle geometry  

E-Print Network (OSTI)

Propulsion by growing actin networks is a universal mechanism used in many different biological systems. Although the core molecular machinery for actin network growth is well preserved in most cases, the geometry of the propelled obstacle can vary considerably. In recent years, filament orientation distribution has emerged as an important observable characterizing the structure and dynamical state of the growing network. Here we derive several continuum equations for the orientation distribution of filaments growing behind stiff obstacles of various shapes and validate the predicted steady state orientation patterns by stochastic computer simulations based on discrete filaments. We use an ordinary differential equation approach to demonstrate that for flat obstacles of finite size, two fundamentally different orientation patterns peaked at either +35/-35 or +70/0/-70 degrees exhibit mutually exclusive stability, in agreement with earlier results for flat obstacles of very large lateral extension. We calculate and validate phase diagrams as a function of model parameters and show how this approach can be extended to obstacles with piecewise straight contours. For curved obstacles, we arrive at a partial differential equation in the continuum limit, which again is in good agreement with the computer simulations. In all cases, we can identify the same two fundamentally different orientation patterns, but only within an appropriate reference frame, which is adjusted to the local orientation of the obstacle contour. Our results suggest that two fundamentally different network architectures compete with each other in growing actin networks, irrespective of obstacle geometry, and clarify how simulated and electron tomography data have to be analyzed for non-flat obstacle geometries.

Julian Weichsel; Ulrich S. Schwarz

2013-04-13T23:59:59.000Z

238

Spatially Continuous Mixed P2-P1 Solutions for Planar Geometry  

DOE Green Energy (OSTI)

Even-order Legendre polynomial (P{sub N}) expansion approximations of the neutron transport equation have historically seen only limited practical application. Research in the last decade has resolved one of the historical theoretical objections to the use of even-order PN approximations in planar geometry, namely the ambiguity in the prescription of boundary conditions as a result of an odd number of unknowns. This research also demonstrated the P{sub 2} approximation to be more accurate than the P{sub 1} approximation in planar geometry away from boundary layers and material interfaces. Neither the P{sub 1} nor the P{sub 2} approximation is convincingly more accurate near material interfaces. This progress motivated the reexamination of the multidimensional simplified P{sub 2} (SP{sub 2}) approximation, the development of P{sub 2} approximations for planar geometry stochastic transport problems, and the examination of the P{sub 2} and SP{sub 2} approximations as a synthetic acceleration technique for the discrete ordinates equations. The major remaining objection to even-order PN approximations is that the scalar flux distributions obtained using these approximations can exhibit large spatial discontinuities at material interfaces and source discontinuities. In contrast, the odd-order PN approximations typically utilized give spatially continuous scalar flux distributions at these locations. In this paper, we propose a mixed P{sub 2}-P{sub 1} angular approximation designed to take advantage of the improved accuracy of the P{sub 2} approximation in the interior of material regions and near external boundaries while retaining the continuous solutions obtained by the P{sub 1} approximation near material interfaces and source discontinuities. We present numerical results from a series of eigenvalue calculations to demonstrate the accuracy of the mixed P{sub 2}-P{sub 1} angular approximation.

Brantley, P S

2004-06-04T23:59:59.000Z

239

Study of Plasma Detachment in a Simplified 2D Geometry using UEDGE  

SciTech Connect

The location of the ionization front in a generic, detached plasma has been studied in a two-dimensional slab geometry by varying the core plasma density and input heating power. The ratio of the recombination to ionization current and the momentum losses in the computational domain have been used to quantify the degree of detachment. Contours of constant ratio of these parameter in the core plasma density--heating power parameter space show that at high input power higher momentum losses can be achieved even at low density. High fraction of recombination, however, require high core densities to sufficiently separate the plasma from the target plate.

Groth, M; Mahdavi, A M; Porter, G D; Rognlien, T D

2001-08-31T23:59:59.000Z

240

Spectral Line Broadening and Angular Blurring due to Spacetime Geometry Fluctuations  

E-Print Network (OSTI)

We treat two possible phenomenological effects of quantum fluctuations of spacetime geometry: spectral line broadening and angular blurring of the image of a distance source. A geometrical construction will be used to express both effects in terms of the Riemann tensor correlation function. We apply the resulting expressions to study some explicit examples in which the fluctuations arise from a bath of gravitons in either a squeezed state or a thermal state. In the case of a squeezed state, one has two limits of interest: a coherent state which exhibits classical time variation but no fluctuations, and a squeezed vacuum state, in which the fluctuations are maximized.

R. T. Thompson; L. H. Ford

2006-01-30T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

A Dodecalogue of Basic Didactics from Applications of Abstract Differential Geometry to Quantum Gravity  

E-Print Network (OSTI)

We summarize the twelve most important in our view novel concepts that have arisen, based on results that have been obtained, from various applications of Abstract Differential Geometry (ADG) to Quantum Gravity (QG). The present document may be used as a concise, yet informal, discursive and peripatetic conceptual guide-cum-terminological glossary to the voluminous technical research literature on the subject. In a bonus section at the end, we dwell on the significance of introducing new conceptual terminology in future QG research by means of `poetic language'

Raptis, I

2006-01-01T23:59:59.000Z

242

A Dodecalogue of Basic Didactics from Applications of Abstract Differential Geometry to Quantum Gravity  

E-Print Network (OSTI)

We summarize the twelve most important in our view novel concepts that have arisen, based on results that have been obtained, from various applications of Abstract Differential Geometry (ADG) to Quantum Gravity (QG). The present document may be used as a concise, yet informal, discursive and peripatetic conceptual guide-cum-terminological glossary to the voluminous technical research literature on the subject. In a bonus section at the end, we dwell on the significance of introducing new conceptual terminology in future QG research by means of `poetic language'

Ioannis Raptis

2006-07-10T23:59:59.000Z

243

Power Electronics Design Implications of Novel Photovoltaic Collector Geometries and Their Application for Increased Energy Harvest  

E-Print Network (OSTI)

The declining cost of photovoltaic (PV) modules has enabled the vision of ubiquitous photovoltaic (PV) power to become feasible. Emerging PV technologies are facilitating the creation of intentionally non-flat PV modules, which create new applications for this sustainable energy generation currently not possible with the traditional rigid, flat silicon-glass modules. However, since the photovoltaic cells are no longer coplanar, there are significant new requirements for the power electronics necessary to convert the native form of electricity into a usable form and ensure maximum energy harvest. Non-uniform insolation from cell-to-cell gives rise to non-uniform current density in the PV material, which limits the ability to create series-connected cells without bypass diode or other ways to shunt current, which is well known in the maximum power tracking literature. This thesis presents a modeling approach to determine and quantify the variations in generation of energy due to intentionally non-flat PV geometries. This will enable the power electronics circuitry to be optimized to harvest maximum energy from PV pixel elements clusters of PV cells with similar operating characteristics. This thesis systematically compares different geometries with identical two-dimensional projection "footprints" for energy harvest throughout the day. The results show that for the same footprint, a semi-cylindrical surface harvests more energy over a typical day than a flat plate. The modeling approach is then extended to demonstrate that by using non flat geometries for PV panel, the availability of a remotely located stand-alone power system can be increased when compared to a flat panel of same footprint. These results have broad application to a variety of energy scavenging scenarios in which either total energy harvested needs to be maximized or unusual geometries for the PV active surfaces are required, including building-integrated PV. This thesis develops the analysis of the potential energy harvest gain for advanced non-planar PV collectors as a necessary first step towards the design of the power electronics circuits and control algorithms to take advantage of the new opportunities of conformal and non-flat PV collectors.

Karavadi, Amulya

2011-08-01T23:59:59.000Z

244

Investigation of synchrotron radiation-induced photodesorption in cryosorbing quasi-cooled geometry. Revision 2  

DOE Green Energy (OSTI)

We report 4.2-K photodesorption experiments in two quasi -- closed geometries-a simple tube and a tube with a coaxial perforated liner -- designed to manure separately the desorption coefficients of tightly bound and physisorbed molecules. The results are important for the beam tube vacuum of the next generation of superconducting proton colliders that have been contemplated-the 20-TeV Superconducting Super Collider (SSC) in the United States and the 7.3-TeV Large Hadron Collider (LHC) at CERN.

Anashin, V.V.; Malyshev, O.B.; Osipov, V.N. [AN SSSR, Novosibirsk (Russian Federation). Inst. Yadernoj Fiziki; Maslennikov, I.L.; Turner, W.C. [Superconducting Super Collider Lab., Dallas, TX (United States)

1994-04-01T23:59:59.000Z

245

Curved Spacetime Geometry for Strings and Affine Non-compact Algebras  

E-Print Network (OSTI)

Based on lectures delivered at (1) the AMS meeting at USC, Nov. 1992 (2) Conference on Quantum Aspects of Black Holes, ITP, UC- Santa %Barbara, %%June 1993. (3) 25th Summer Institute, Ecole Normale Superieure, % Paris, Aug. 1992. To appear in "Interface Between Mathematics and Physics", Ed. S.-T. Yau. 1--Itroduction to String Theory in Curved Spacetime 2--G/H Coset Conformal Field Theory and String Theory 3--Time, Space and Classification of Non-Compact Cosets 4--Heterotic Strings in Curved Spacetime as gauged WZW Models 5--The Spacetime Manifold and the Geometry 6--Examples in 2D, 3D and 4D

Bars, Itzhak

1993-01-01T23:59:59.000Z

246

Propagation of light in serially coupled plasmonic nanowire dimer: Geometry dependence and polarization control  

SciTech Connect

We experimentally studied plasmon-polariton-assisted light propagation in serially coupled silver nanowire (Ag-NW) dimers and probed their dependence on bending-angle between the nanowires and polarization of incident light. From the angle-dependence study, we observed that obtuse angles between the nanowires resulted in better transmission than acute angles. From the polarization studies, we inferred that light emission from junction and distal ends of Ag-NW dimers can be systematically controlled. Further, we applied this property to show light routing and polarization beam splitting in obtuse-angled Ag-NW dimer. The studied geometry can be an excellent test-bed for plasmonic circuitry.

Singh, Danveer; Raghuwanshi, Mohit; Pavan Kumar, G. V. [Photonics and Optical Nanoscopy Laboratory, Department of Physics and Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008 (India)

2012-09-10T23:59:59.000Z

247

Equilibrium Geometries, Reaction Pathways, and Electronic Structures of Ethanol Adsorbed on the Si (111) Surface  

E-Print Network (OSTI)

Equilibrium atomic configurations and electron energy structure of ethanol adsorbed on the Si (111) surface are studied by the first-principles density functional theory. Geometry optimization is performed by the total energy minimization method. Several equilibrium atomic configurations of ethanol, both undissociated and dissociated, on the Si (111) surface are found. Reaction pathways and predicted transition states are discussed in comparison with available experimental data in terms of the feasibility of the reactions occurring. Analysis of atom and orbital resolved projected density of states indicate substantial modifications of the Si surface valence and conduction bands due to the adsorption of ethanol affecting the electrical properties of the surface.

Gavrilenko, A V; Gavrilenko, V I

2008-01-01T23:59:59.000Z

248

Raman Shift of Stressed Diamond Anvils: Pressure Calibration and Culet Geometry Dependence  

DOE Green Energy (OSTI)

The pressure dependence of the Raman shift of diamond for highly stressed anvils at the diamond-anvil sample interface has been measured for different culet shapes up to 180 GPa at ambient temperature. By using hydrogen samples, which constitute both a quasi-hydrostatic medium and a sensitive pressure sensor, some of the effects of culet and tip size have been determined. We propose that the divergent results in the literature can be partly ascribed to different anvil geometries. Experiments show increasing second order dependence of the diamond Raman shift with pressure for decreasing tip size. This is an important consideration when using the diamond anvils as a pressure sensor.

Baer, B J; Chang, M E; Evans, W J

2008-04-03T23:59:59.000Z

249

Synthesis of acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters  

DOE Patents (OSTI)

A process of preparing an acid addition salt of delta-aminolevulinc acid comprising: a) dissolving a lower alkyl 5-bromolevulinate and hexamethylenetetramine in a solvent selected from the group consisting of water, ethyl acetate, chloroform, acetone, ethanol, tetrahydrofuran and acetonitrile, to form a quaternary ammonium salt of the lower alkyl 5-bromolevulinate; and b) hydrolyzing the quaternary ammonium salt with an inorganic acid to form an acid addition salt of delta-aminolevulinic acid.

Moens, Luc (Lakewood, CO)

2003-06-24T23:59:59.000Z

250

Topological Defects, Surface Geometry and Cohesive Energy of Twisted Filament Bundles  

E-Print Network (OSTI)

Cohesive assemblies of filaments are a common structural motif found in diverse contexts, ranging from biological materials such as fibrous proteins, to artificial materials such as carbon nanotube ropes and micropatterned filament arrays. In this paper, we analyze the complex dependence of cohesive energy on twist, a key structural parameter of both self-assembled and fabricated filament bundles. Based on the analysis of simulated ground states of cohesive bundles, we show that the non-linear influence of twist derives from two distinct geometric features of twisted bundles: (i) the geometrical frustration of inter-filament packing in the bundle cross-section; and (ii) the evolution of the surface geometry of bundles with twist, which dictates the cohesive cost of non-contacting filaments at the surface. Packing frustration in the bundle core gives rise to the appearance of a universal sequence of topological defects, excess 5-fold disclinations, with increasing twist, while the evolution of filament contact at the surface of the bundle generically favors twisted geometries for sufficiently long filaments. Our analysis of both continuum and discrete models of filament bundles shows that, even in the absence of external torque or intrinsic chirality, cohesive energy universally favors twisted ground states above a critical (length/radius) aspect ratio and below a critical filament stiffness threshold.

Isaac R. Bruss; Gregory M. Grason

2013-03-06T23:59:59.000Z

251

Nonlinear kinetic modeling of stimulated Raman scattering in a multidimensional geometry  

Science Conference Proceedings (OSTI)

In this paper, we derive coupled envelope equations modeling the growth of stimulated Raman scattering (SRS) in a multi-dimensional geometry and accounting for nonlinear kinetic effects. In particular, our envelope equations allow for the nonlinear reduction of the Landau damping rate, whose decrease with the plasma wave amplitude depends on the rate of side-loss. Account is also made of the variations in the extent of the plasma wave packet entailed by the collisionless dissipation due to trapping. The dephasing between the electron plasma wave (EPW) and the laser drive, as well as the self-focussing of the plasma wave, both induced by the EPW nonlinear frequency shift, are also included in our envelope equations. These equations are solved in a multi-dimensional geometry using our code dubbed BRAMA, whose predictions regarding the evolution of Raman reflectivity as a function of the laser intensity are compared against previously published particle in cell results, thus illustrating the ability of BRAMA simulations to provide the correct laser threshold intensity for SRS as well as the right order of magnitude of Raman reflectivity above threshold.

Benisti, D.; Morice, O.; Gremillet, L.; Friou, A.; Lefebvre, E. [CEA, DAM, DIF F-91297 Arpajon (France)

2012-05-15T23:59:59.000Z

252

Analyzing X-Ray Pulsar Profiles: Geometry and Beam Pattern of EXO 2030+375  

E-Print Network (OSTI)

The pulse profiles of the transient Be/X-ray binary EXO 2030+375 show strong dependence on energy, as well as on its luminosity state, and are asymmetric in shape. We want to identify the emission components of the two magnetic poles in the pulsed emission to understand the geometry of the neutron star and its beam pattern. We utilize a pulse-profile decomposition method that enables us to find two symmetric pulse profiles from the magnetic poles of the neutron star. The symmetry characteristics of these single-pole pulse profiles give information about the position of the magnetic poles of the neutron star relative to its rotation axis. We find a possible geometry for the neutron star in EXO 2030+375 through the decomposition of the pulse profiles, which suggests that one pole gets closer to the line of sight than the other and that, during the revolution of the neutron star, both poles disappear behind the horizon for a short period of time. A considerable fraction of the emission arises from a halo while t...

Sasaki, Manami; Kraus, Ute; Caballero, Isabel; Santangelo, Andrea

2010-01-01T23:59:59.000Z

253

Searching for optimal mitigation geometries for laser resistant multilayer high reflector coatings  

SciTech Connect

Growing laser damage sites on multilayer high reflector coatings can limit mirror performance. One of the strategies to improve laser damage resistance is to replace the growing damage sites with pre-designed benign mitigation structures. By mitigating the weakest site on the optic, the large aperture mirror will have a laser resistance comparable to the intrinsic value of the multilayer coating. To determine the optimal mitigation geometry, the finite difference time domain method (FDTD) was used to quantify the electric-field intensification within the multilayer, at the presence of different conical pits. We find that the field intensification induced by the mitigation pit is strongly dependent on the polarization and the angle of incidence (AOI) of the incoming wave. Therefore the optimal mitigation conical pit geometry is application specific. Furthermore, our simulation also illustrates an alternative means to achieve an optimal mitigation structure by matching the cone angle of the structure with the AOI of the incoming wave, except for the p-polarization wave at a range of incident angles between 30{sup o} and 45{sup o}.

Qiu, S R; Wolfe, J E; Monterrosa, A M; Feit, M D; Pistor, T V; STolz, C J

2011-02-11T23:59:59.000Z

254

Critical Parameters of Complex Geometry Intersecting Cylinders Containing Uranyl Nitrate Solution  

SciTech Connect

About three dozen previously unreported critical configurations are presented for very complex geometries filled with high concentration enriched uranyl nitrate solution. These geometries resemble a tall, thin Central Column (or trunk of a "tree") having long, thin arms (or "branches") extending up to four directions off the column. Arms are equally spaced from one another in vertical planes; and that spacing ranges from arms in contact to quite wide spacings. Both the Central Column and the many different arms are critically safe by themselves when each, alone, is filled with fissile solution; but, in combination, criticality occurs due to the interactions between arms and the column. Such neutronic interactions formed the principal focus of this study. While these results are fresh to the nuclear criticality safety industry and to those seeking novel experiments against which to validate computer codes, the experiments, themselves, are not recent. Over 100 experiments were performed at the Rocky Flats Critical Mass Laboratory between September, 1967, and February of the following year.

Rothe, Robert Emil; Briggs, Joseph Blair

1999-06-01T23:59:59.000Z

255

Revisiting the Recommended Geometry for the Diametrally Compressed Ceramic C-Ring Specimen  

SciTech Connect

A study conducted several years ago found that a stated allowable width/thickness (b/t) ratio in ASTM C1323 (Standard Test Method for Ultimate Strength of Advanced Ceramics with Diametrally Compressed C-Ring Specimens at Ambient Temperature) could ultimately cause the prediction of a non-conservative probability of survival when the measured C-ring strength was scaled to a different size. Because of that problem, this study sought to reevaluate the stress state and geometry of the C-ring specimen and suggest changes to ASTM C1323 that would resolve that issue. Elasticity, mechanics of materials, and finite element solutions were revisited with the C ring geometry. To avoid the introduction of more than 2% error, it was determined that the C ring width/thickness (b/t) ratio should range between 1-3 and that its inner radius/outer radius (ri/ro) ratio should range between 0.50-0.95. ASTM C1323 presently allows for b/t to be as large as 4 so that ratio should be reduced to 3.

Jadaan, Osama M. [University of Wisconsin, Platteville; Wereszczak, Andrew A [ORNL

2009-04-01T23:59:59.000Z

256

Numerical simulation of high-energy-electron gerated field in dielectrics of various geometries. Final report, June 1, 1979-May 15, 1980  

SciTech Connect

It has been observed that the exposure of dielectrics to electron beams can produce an electric field of sufficient magnitude to cause dielectric breakdown. The present investigations will be directed to calculate the electric field intensity in dielectrics under spherical and cylindrical geometries. In the spherical geometry the method of multiple images renders the full numerical calculation unnecessary, whereas in a finite length cylindrical geometry the full numerical calculation seems to be inevitable. A description and results of the spherical geometry are presented and a more detailed presentation of the finite cylinder geometry is given.

Yee, K.S.

1980-01-01T23:59:59.000Z

257

Acid Placement in Acid Jetting Treatments in Long Horizontal Wells  

E-Print Network (OSTI)

In the Middle East, extended reach horizontal wells (on the order of 25,000 feet of horizontal displacement) are commonly acid stimulated by jetting acid out of drill pipe. The acid is jetted onto the face of the openhole wellbore as the drill pipe is withdrawn from the well. The jetting action helps to remove the drilling fluid filter cake and promote the acid to penetrate into the formation and form wormholes to stimulate the well. However, with very long sections of wellbore open to flow, the acid placement and subsequent wormhole distribution and penetration depths are uncertain. This study has modeled the acid jetting process using a comprehensive model of acid placement and wormhole propagation in a horizontal well. It is presumed that the acid jetting tool removes the drilling mud filter cake, so that no filter cake exists between the end of the drill pipe and the toe of the well. Correspondingly, the model also assumes that there is an intact, low-permeability filter cake on the borehole wall between the end of the drill pipe and the heel of the well. The drill pipe is modeled as being withdrawn from the well during the acid jetting treatment, as is done in practice. The acidizing simulator predicts the distribution of acid and the depths of wormholes formed as functions of time and position during the acid jetting treatment. The model shows that the acid jetting process as typically applied in these wells preferentially stimulates the toe region of the horizontal well. Comparisons of the simulation predictions with published data for acid jetting treatments in such wells showed good general agreement. Based on the simulation study, this study presents recommendations for improved acid jetting treatment procedures to improve the distribution of acid injected into the formation.

Sasongko, Hari

2012-05-01T23:59:59.000Z

258

Lubrication with boric acid additives  

DOE Patents (OSTI)

Self-lubricating resin compositions including a boric acid additive and a synthetic polymer including those thermoset materials.

Erdemir, Ali (Naperville, IL)

2000-01-01T23:59:59.000Z

259

A COMPARISON OF MEASURED AND CALCULATED GAMMA RAY ATTENUATION FOR A COMMON COUNTING GEOMETRY  

Science Conference Proceedings (OSTI)

In order to perform quantitative gamma spectroscopy, it is necessary to know the sample-specific detection efficiency for photons as a function of energy. The detection efficiency, along with the branching ratio for the isotope and gamma ray of interest, is used to convert observed counts/second to actual disintegrations/second, and, hence, has a large effect on the accuracy of the measurement. In cases where the geometry of the source is simple and reproducible, such as a point source, small vial of solid, or jar of liquid, geometry-specific standards may be counted to determine the detection efficiency. In cases where the samples are large, irregular, or unique, this method generally cannot be used. For example, it is impossible to obtain a NIST-traceable standard glovebox or 55-gallon drum. In these cases, a combination of measured absolute detector efficiency and calculated sample-specific correction factors is commonly used. The correction factors may be calculated via Monte Carlo simulation of the item (the method used by Canberra's ISOCS system), or via semi-empirical calculation of matrix and container attenuations based on the thickness and composition of the container and radioactive matrix (ISOTOPIC by EG&G Ortec uses this method). The accuracy of these correction factors for specific geometries is often of vital interest when assessing the quality of gamma spectroscopy data. During the Building 251 Risk-Reduction Project, over 100 samples of high activity actinides will be characterized via gamma spectroscopy, typically without removing the material from the current storage containers. Most of the radioactive materials in B-251 are stored in cylindrical stainless steel canisters (called USV containers, after the Underground Storage Vaults they are commonly stored in), 13 cm in diameter, by 28 cm high, with walls that are 1.8 mm thick. While the actual samples have a variety of configurations inside the USV container, a very common configuration is the material (usually as an oxide powder pellet of approximately 2 cm diameter by {approx}2 mm thick) in a squat glass jar, with the jar placed in a thin steel food-pack can, which is then placed in the bottom of the USV canister. During data acquisition, the USV containers are typically rotated at approximately 4 rpm on a turntable to eliminate errors due to the material not being centered in the can, or attenuation not being isotropic. An aluminum plate is placed over the container, secured by three vertical rods, to securely hold the container. Pictures of both the containers, and this typical counting configuration are shown below.

Gaylord, R F

2004-02-26T23:59:59.000Z

260

CZT detectors used in different irradiation geometries: Simulations and experimental results  

Science Conference Proceedings (OSTI)

The purpose of this work was to evaluate potential advantages and limitations of CZT detectors used in surface-on, edge-on, and tilted angle irradiation geometries. Simulations and experimental investigations of the energy spectrum measured by a CZT detector have been performed using different irradiation geometries of the CZT. Experiments were performed using a CZT detector with 10x10 mm{sup 2} size and 3 mm thickness. The detector was irradiated with collimated photon beams from Am-241 (59.5 keV) and Co-57 (122 keV). The edge-scan method was used to measure the detector response function in edge-on illumination mode. The tilted angle mode was investigated with the radiation beam directed to the detector surface at angles of 90 degree sign , 15 degree sign , and 10 degree sign . The Hecht formalism was used to simulate theoretical energy spectra. The parameters used for simulations were matched to experiment to compare experimental and theoretical results. The tilted angle CZT detector suppressed the tailing of the spectrum and provided an increase in peak-to-total ratio from 38% at 90 degree sign to 83% at 10 degree sign tilt angle for 122 keV radiation. The corresponding increase for 59 keV radiation was from 60% at 90 degree sign to 85% at 10 degree sign tilt angle. The edge-on CZT detector provided high energy resolution when the beam thickness was much smaller than the thickness of CZT. The FWHM resolution in edge-on illumination mode was 4.2% for 122 keV beam with 0.3 mm thickness, and rapidly deteriorated when the thickness of the beam was increased. The energy resolution of surface-on geometry suffered from strong tailing effect at photon energies higher than 60 keV. It is concluded that tilted angle CZT provides high energy resolution but it is limited to a 1D linear array configuration. The surface-on CZT provides 2D pixel arrays but suffers from tailing effect and charge build up. The edge-on CZT is considered suboptimal as it requires small beam thickness and also suffers from charge buildup.

Fritz, Shannon G.; Shikhaliev, Polad M. [Imaging Physics Laboratory, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

2009-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Adsorptive Membranes vs. Resins for Acetic Acid Removal from Biomass Hydrolysates  

Science Conference Proceedings (OSTI)

Acetic acid is a compound commonly found in hemicellulosic hydrolysates. This weak acid strongly influences the bioconversion of sugar containing hydrolysates. Previous investigators have used anion exchange resins for acetic acid removal from different hemicellulosic hydrolysates. In this study, the efficiency of an anion exchange membrane was compared to that of an anion exchange resin, for acetic acid removal from a DI water solution and an acidic hemicellulose hydrolysate pretreated using two different methods. Ion exchange membranes and resins have very different geometries. Here the performance of membranes and resins is compared using two dimensionless parameters, the relative mass throughput and chromatographic bed number. The relative mass throughput arises naturally from the Thomas solution for ion exchange. The results show that the membrane exhibit better performance in terms of capacity, and loss of the desired sugars. In addition acetic acid may be eluted at a higher concentration from the membrane thus leading to the possibility of recovery and re-use of the acetic acid.

Han, B.; Carvalho, W.; Canilha, L.; da Silva, S. S.; e Silva, J. B. A.; McMillan, J. D.; Wickramasinghe, S. R.

2006-01-01T23:59:59.000Z

262

System for conversion between the boundary representation model and a constructive solid geometry model of an object  

DOE Patents (OSTI)

A system converts from the boundary representation of an object to the constructive solid geometry representation thereof. The system converts the boundary representation of the object into elemental atomic geometrical units or I-bodies which are in the shape of stock primitives or regularized intersections of stock primitives. These elemental atomic geometrical units are then represented in symbolic form. The symbolic representations of the elemental atomic geometrical units are then assembled heuristically to form a constructive solid geometry representation of the object usable for manufacturing thereof. Artificial intelligence is used to determine the best constructive solid geometry representation from the boundary representation of the object. Heuristic criteria are adapted to the manufacturing environment for which the device is to be utilized. The surface finish, tolerance, and other information associated with each surface of the boundary representation of the object are mapped onto the constructive solid geometry representation of the object to produce an enhanced solid geometry representation, particularly useful for computer-aided manufacture of the object.

Christensen, Noel C. (Kansas City, MO); Emery, James D. (Kansas City, MO); Smith, Maurice L. (Kansas City, MO)

1988-04-05T23:59:59.000Z

263

System for conversion between the boundary representation model and a constructive solid geometry model of an object  

DOE Patents (OSTI)

A system converts from the boundary representation of an object to the constructive solid geometry representation thereof. The system converts the boundary representation of the object into elemental atomic geometrical units or I-bodies which are in the shape of stock primitives or regularized intersections of stock primitives. These elemental atomic geometrical units are then represented in symbolic form. The symbolic representations of the elemental atomic geometrical units are then assembled heuristically to form a constructive solid geometry representation of the object usable for manufacturing thereof. Artificial intelligence is used to determine the best constructive solid geometry representation from the boundary representation of the object. Heuristic criteria are adapted to the manufacturing environment for which the device is to be utilized. The surface finish, tolerance, and other information associated with each surface of the boundary representation of the object are mapped onto the constructive solid geometry representation of the object to produce an enhanced solid geometry representation, particularly useful for computer-aided manufacture of the object. 19 figs.

Christensen, N.C.; Emery, J.D.; Smith, M.L.

1985-04-29T23:59:59.000Z

264

Geometry, Heat Removal and Kinetics Scoping Models for Hydrogen Storage Systems  

NLE Websites -- All DOE Office Websites (Extended Search)

WSRC-TR-2007-00439, REVISION 0 WSRC-TR-2007-00439, REVISION 0 Keywords: Hydrogen Kinetics, Hydrogen Storage Vessel Metal Hydride Retention: Permanent Geometry, Heat Removal and Kinetics Scoping Models for Hydrogen Storage Systems Bruce J. Hardy November 16, 2007 Washington Savannah River Company Savannah River Site Aiken, SC 29808 Prepared for the U.S. Department of Energy Under Contract Number DEAC09-96-SR18500 DISCLAIMER This report was prepared for the United States Department of Energy under Contract No. DE-AC09-96SR18500 and is an account of work performed under that contract. Neither the United States Department of Energy, nor WSRC, nor any of their employees makes any warranty, expressed or implied, or assumes any legal liability or responsibility for accuracy, completeness, or

265

Low torque hydrodynamic lip geometry for bi-directional rotation seals  

DOE Patents (OSTI)

A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.

Dietle, Lannie L. (Houston, TX); Schroeder, John E. (Richmond, TX)

2011-11-15T23:59:59.000Z

266

Low torque hydrodynamic lip geometry for bi-directional rotation seals  

DOE Patents (OSTI)

A hydrodynamically lubricating geometry for the generally circular dynamic sealing lip of rotary seals that are employed to partition a lubricant from an environment. The dynamic sealing lip is provided for establishing compressed sealing engagement with a relatively rotatable surface, and for wedging a film of lubricating fluid into the interface between the dynamic sealing lip and the relatively rotatable surface in response to relative rotation that may occur in the clockwise or the counter-clockwise direction. A wave form incorporating an elongated dimple provides the gradual convergence, efficient impingement angle, and gradual interfacial contact pressure rise that are conducive to efficient hydrodynamic wedging. Skewed elevated contact pressure zones produced by compression edge effects provide for controlled lubricant movement within the dynamic sealing interface between the seal and the relatively rotatable surface, producing enhanced lubrication and low running torque.

Dietle, Lannie L. (Houston, TX); Schroeder, John E. (Richmond, TX)

2009-07-21T23:59:59.000Z

267

Double quantum dot with tunable coupling in a Si MOS device with lateral geometry.  

Science Conference Proceedings (OSTI)

We report low-temperature transport measurements of a silicon metal-oxide-semiconductor (MOS) double quantum dot (DQD). In contrast to previously reported measurements of DQD's in Si MOS structures, our device has a lateral gate geometry very similar to that used by Petta et al. to demonstrate coherent manipulation of single electron spins. This gate design provides a high degree of tunability, allowing for independent control over individual dot occupation and tunnel barriers, as well as the ability to use nearby constrictions to sense dot charge occupation. Comparison of experimentally extracted capacitances between the dot and nearby gates with electrostatic modeling demonstrates the presence of disorder and the ability to partially compensate for this disorder by adjustment of gate voltages. We experimentally show gate-controlled tuning of the interdot coupling over a wide range of energies, an important step towards potential quantum computing applications.

Wendt, Joel Robert; Ten Eyck, Gregory A.; Childs, Kenton David; Tracy, Lisa A.; Pinilla, C. Borras (University of Oklahoma, Norman, OK); Eng, Kevin; Eriksson, Mark A. (University of Wisconsin-Madison, Madison, WI); Nordberg, Eric; Carroll, Malcolm S.; Stevens, J.; Young, Ralph Watson; Lilly, Michael Patrick; Stalford, Harold Lenn

2010-08-01T23:59:59.000Z

268

Engineering the geometry of stripe-patterned surfaces towards efficient wettability switching  

E-Print Network (OSTI)

The ability to control wettability is important for a wide range of technological applications in which precise microfluidic handling is required. It is known that predesigned roughness at a micro- or nano- scale enhances the wetting properties of solid materials giving rise to super-hydrophobic or super-hydrophilic behavior. In this work, we study the dependence of the apparent wettability of a stripe-patterned solid surface on the stripe geometry, utilizing systems level analysis and mesoscopic Lattice-Boltzmann (LB) simulations. Through the computation of both stable and unstable states we are able to determine the energy barriers separating distinct metastable wetting states that correspond to the well-known Cassie and Wenzel states. This way the energy cost for inducing certain wetting transitions is computed and its dependence on geometric features of the surface pattern is explored.

Michail E. Kavousanakis; Carlos E. Colosqui; Athanasios G. Papathanasiou

2013-04-08T23:59:59.000Z

269

Multiple-stripe lithiation mechanism of individual SnO2 nanowires in a flooding geometry  

SciTech Connect

The atomic scale lithiation mechanism of individual SnO2 nanowires in a flooding geometry with the entire wires being immersed in the electrolyte was revealed by in-situ transmission electron microscopy. The lithiation initiated multiple stripes with width of a few nanometer parallel to {l_brace}020{r_brace} planes transversing the entire wires, serving as multiple reaction fronts for late stage of lithiation. Inside the stripes, we identified high density of dislocations and enlarged inter-planar spacing, which provide effective path for lithium ion transport. The density of the stripes increased with further lithiation, and eventually they merged with one another, causing a large enlongation and volume expansion and the crystalline to amorphous phase transformation. This multiple stripes and multiple reaction fronts lithiation mechanism is unexpected and differs completely from the expected core-shell lithiation mechanism.

Zhong, Li; Liu, Xiao H.; Wang, G. F.; Mao, Scott X.; Huang, Jian Yu

2011-06-17T23:59:59.000Z

270

On non-abelian T-dual geometries with Ramond fluxes  

E-Print Network (OSTI)

We show how to implement T-duality along non-abelian isometries in backgrounds with non-vanishing Ramond fields. When the dimension of the isometry group is odd (even) the duality swaps (preserves) the chirality of the theory. In certain cases a non-abelian duality can result in a massive type-IIA background. We provide two examples by dualising SU(2) isometry subgroups in $AdS_5\\times S^5$ and $AdS_3\\times S^3\\times T^4$. The resultant dual geometries inherit the original AdS factors but have transverse spaces with reduced isometry and preserve only half of the original supersymmetry. The non-abelian dual of $AdS_5\\times S^5$ has an M-theory lift which is related to the gravity duals of N=2 superconformal theories. We comment on a possible interpretation of this as a high spin limit.

Konstadinos Sfetsos; Daniel C. Thompson

2010-12-06T23:59:59.000Z

271

The Effects of Geometry on the Corona-to-Streamer Discharge Transition  

E-Print Network (OSTI)

The electric spark discharge has been studied for hundreds of years, yet many details of the phenomenon remain elusive. One particular area in the field of spark discharges that has yet to be explored in depth is the transition region between the corona and the streamer discharge. The parameters that characterize the transition region are purely geometric for a given potential difference applied between two electrodes. For the case of a point-to-plane electrode geometry, the transition between the oscillating corona discharge and the rapidly-growing streamer discharge is determined by the radius of curvature of the anode. In this contribution, the transition radius of curvature is found analytically using simplified models of each discharge and the principle of least action. For a sufficiently small anode, the corona discharge is also shown to be energetically more favorable at all radii of curvature, supporting the general claim that corona discharges are most readily produced on thin wires.

Humbird, Kelli D

2013-05-01T23:59:59.000Z

272

Mesoscopic model for filament orientation in growing actin networks: the role of obstacle geometry  

E-Print Network (OSTI)

Propulsion by growing actin networks is a universal mechanism used in many different biological systems. Although the core molecular machinery for actin network growth is well preserved in most cases, the geometry of the propelled obstacle can vary considerably. In recent years, filament orientation distribution has emerged as an important observable characterizing the structure and dynamical state of the growing network. Here we derive several continuum equations for the orientation distribution of filaments growing behind stiff obstacles of various shapes and validate the predicted steady state orientation patterns by stochastic computer simulations based on discrete filaments. We use an ordinary differential equation approach to demonstrate that for flat obstacles of finite size, two fundamentally different orientation patterns peaked at either +35/-35 or +70/0/-70 degrees exhibit mutually exclusive stability, in agreement with earlier results for flat obstacles of very large lateral extension. We calculat...

Weichsel, Julian; 10.1088/1367-2630/15/3/035006

2013-01-01T23:59:59.000Z

273

How to Extract the Geometry and Topology from Very Large 3D Segmentations  

E-Print Network (OSTI)

Segmentation is often an essential intermediate step in image analysis. A volume segmentation characterizes the underlying volume image in terms of geometric information--segments, faces between segments, curves in which several faces meet--as well as a topology on these objects. Existing algorithms encode this information in designated data structures, but require that these data structures fit entirely in Random Access Memory (RAM). Today, 3D images with several billion voxels are acquired, e.g. in structural neurobiology. Since these large volumes can no longer be processed with existing methods, we present a new algorithm which performs geometry and topology extraction with a runtime linear in the number of voxels and log-linear in the number of faces and curves. The parallelizable algorithm proceeds in a block-wise fashion and constructs a consistent representation of the entire volume image on the hard drive, making the structure of very large volume segmentations accessible to image analysis. The paral...

Andres, Bjoern; Kroeger, Thorben; Hamprecht, Fred A

2010-01-01T23:59:59.000Z

274

Hybrid RHF/MP2 geometry optimizations with the Effective Fragment Molecular Orbital Method  

E-Print Network (OSTI)

The frozen domain Effective Fragment Molecular Orbital method (\\textit{PLoS ONE}, accepted) is extended to allow for the treatment of a single fragment at the MP2 level of theory. The approach is applied to the conversion of chorismate to phrephenate by chorismate mutase, where the substrate is treated at the MP2 level of theory while the rest of the system is treated at the RHF level. MP2 geometry optimization is found to lower the barrier by up to 3.5 kcal/mol compared to RHF optimzations and ONIOM energy refinement and leads to smoother convergence with respect to basis set for the reaction profile. For double zeta basis sets the increase in CPU time relative to RHF is roughly a factor of two.

Christensen, Anders S; Fedorov, Dimitri G; Jensen, Jan H

2013-01-01T23:59:59.000Z

275

Oscillation modes of direct current microdischarges with parallel-plate geometry  

SciTech Connect

Two different oscillation modes in microdischarge with parallel-plate geometry have been observed: relaxation oscillations with frequency range between 1.23 and 2.1 kHz and free-running oscillations with 7 kHz frequency. The oscillation modes are induced by increasing power supply voltage or discharge current. For a given power supply voltage, there is a spontaneous transition from one to other oscillation mode and vice versa. Before the transition from relaxation to free-running oscillations, the spontaneous increase of oscillation frequency of relaxation oscillations form 1.3 kHz to 2.1 kHz is measured. Fourier transform spectra of relaxation oscillations reveal chaotic behavior of microdischarges. Volt-ampere (V-A) characteristics associated with relaxation oscillations describes periodical transition between low current, diffuse discharge, and normal glow. However, free-running oscillations appear in subnormal glow only.

Stefanovic, Ilija; Kuschel, Thomas; Winter, Joerg [Institut fuer Experimentalphysik II, Ruhr-Universitaet Bochum, 44781 Bochum (Germany); Skoro, Nikola; Maric, Dragana; Petrovic, Zoran Lj [Institute of Physics, University of Belgrade, POB 68, 11080 Belgrade (Serbia)

2011-10-15T23:59:59.000Z

276

Fundamental solution of the Laplacian in the hyperboloid model of hyperbolic geometry  

E-Print Network (OSTI)

Due to the isotropy of $d$-dimensional hyperbolic space, one expects there to exist a spherically symmetric fundamental solution for its corresponding Laplace-Beltrami operator. The $R$-radius hyperboloid model of hyperbolic geometry $\\Hi_R^d$ with $R>0$, represents a Riemannian manifold with negative-constant sectional curvature. We obtain a spherically symmetric fundamental solution of Laplace's equation on this manifold in terms of its geodesic radius. We give several matching expressions for this fundamental solution including a definite integral over reciprocal powers of the hyperbolic sine, finite summation expression over hyperbolic functions, Gauss hypergeometric functions, and in terms of the associated Legendre function of the second kind with order and degree given by $d/2-1$ with real argument greater than unity. We also demonstrate uniqueness for a fundamental solution of Laplace's equation on this manifold in terms of a vanishing decay at infinity.

Howard S. Cohl; Ernie G. Kalnins

2012-01-20T23:59:59.000Z

277

Influence of pore geometry on the design of microporous materials for methane storage  

SciTech Connect

The advantages of storing methane by adsorption in microporous materials are briefly reviewed, and the merits of currently available zeolites and microporous carbons are discussed. Grand canonical ensemble Monte-Carlo computer simulations of methane in slit pores (to model porous carbons) and cylindrical pores (to model zeolites) were carried out to determine the best geometry and the optimal pore size for storing the maximum amount of methane at a given storage pressure. At 274K, the optimal material is a porous carbon of pore size sufficient to contain two adsorbed layers of methane. At 500 psi (3.4 MPa), the energy density of such a material at 274K is only a quarter that of gasoline. These results suggest that an optimal zeolitic material would be a less useful material for adsorptive storage of methane than an optimal porous carbon. 21 refs., 10 figs., 3 tabs.

Cracknell, R.F.; Gordon, P.; Gubbins, K.E. (Cornell Univ., Ithaca, NY (United States))

1993-01-14T23:59:59.000Z

278

IBIS: An inverse geometry Brillouin inelastic neutron spectrometer for the SNS  

Science Conference Proceedings (OSTI)

The high power target station at the Spallation Neutron Source (SNS) currently has about 20 completed neutron scattering instruments. With a broad coverage of the momentum transfer (Q)-energy (E) space, these instruments serve an extensive user community. In an effort to further expand the scientific capabilities of the SNS instrument suites, we propose a low background, inverse geometry Brillouin inelastic spectrometer for the SNS which will expand the Q-E coverage of the current instrument suite and facilitate the study of inelastic and quasi-elastic scatterings at low Q values. The possible location for the proposed instrument is either beamline 8 which views the decoupled water moderator, or beamline 14A, which views a cold, coupled super critical hydrogen moderator. The instrument parameters, optimizations, and performances at these two beamline locations are discussed.

Zhao, Jinkui [ORNL; Wildgruber, Christoph U [ORNL; Robertson, Lee [ORNL; Herwig, Kenneth W [ORNL

2013-01-01T23:59:59.000Z

279

Clustered Geometries Exploiting Quantum Coherence Effects for Efficient Energy Transfer in Light Harvesting  

E-Print Network (OSTI)

Elucidating quantum coherence effects and geometrical factors for efficient energy transfer in photosynthesis has the potential to uncover non-classical design principles for advanced organic materials. We study energy transfer in a linear light-harvesting model to reveal that dimerized geometries with strong electronic coherences within donor and acceptor pairs exhibit significantly improved efficiency, which is in marked contrast to predictions of the classical F\\"orster theory. We reveal that energy tuning due to coherent delocalization of photoexcitations is mainly responsible for the efficiency optimization. This coherence-assisted energy-tuning mechanism also explains the energetics and chlorophyll arrangements in the widely-studied Fenna-Matthews-Olson complex. We argue that a clustered network with rapid energy relaxation among donors and resonant energy transfer from donor to acceptor states provides a basic formula for constructing efficient light-harvesting systems, and the general principles revea...

Ai, Qing; Jin, Bih-Yaw; Cheng, Yuan-Chung

2013-01-01T23:59:59.000Z

280

Energy and angular momentum of general 4-dimensional stationary axi-symmetric spacetime in teleparallel geometry  

E-Print Network (OSTI)

We derive an exact general axi-symmetric solution of the coupled gravitational and electromagnetic fields in the tetrad theory of gravitation. The solution is characterized by four parameters $M$ (mass), $Q$ (charge), $a$ (rotation) and $L$ (NUT). We then, calculate the total exterior energy using the energy-momentum complex given by M{\\o}ller in the framework of Weitzenb$\\ddot{o}$ck geometry. We show that the energy contained in a sphere is shared by its interior as well as exterior. We also calculate the components of the spatial momentum to evaluate the angular momentum distribution. We show that the only non-vanishing components of the angular momentum is in the Z direction.

Gamal Gergess Lamee Nashed

2008-01-23T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
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281

Numerical Study of Geometry and Rotation Dependence on the Flow in Labyrinth Seals  

E-Print Network (OSTI)

A computational study was conducted on the flow, both compressible and incompressible, in a labyrinth seal at various geometries and rotation rates. The computations were performed using the commercial software Fluent which solves the k-? model to predict the flow field in the seal. Various clearance-pitch ratios were used to study the effect of clearance on the flow. The aspect ratio, which is defined as the pitch-height ratio was varied to study the influence of the depth of the cavity on the flow as a whole. These studies span a range of Taylor's number that is defined accordingly, while fixing the Reynolds number at 1000. The effects of clearance, aspect ratio and rotational rates are studied using carry-over coefficient and discharge coefficient. It is observed that a secondary recirculation zone (SRZ) occurs inside a seal cavity at above certain Taylor's number. This significantly changes the flow field in the seal and the cavity which results an increases in pressure drop across the seal for a given flow boundary condition. This formation of SRZ's is more evident in incompressible flow and occur at prohibitively high rotational speeds in case of air (compressible flow). It is also observed that flow with teeth on rotor are characterized by SRZ's while it's not case with teeth on stator. A flow map which shows the onset and presence of SRZ's is shown. The ratio of tangential velocity of the shaft to the average of the swirl velocity in a cavity at various geometries of the cavities are presented. They seem to be decreasing with decreasing depth and follow a linear pattern with the aspect ratios of the cavity.

Yamsani, Vamshi Krishna

2011-08-01T23:59:59.000Z

282

Vacuum polarization in asymptotically anti-de Sitter black hole geometries  

E-Print Network (OSTI)

We study the polarization of the vacuum for a scalar field, $phi^2 >$, on an asymptotically anti-de Sitter black hole geometry. The method we follow uses the WKB analytic expansion and point-splitting regularization, similarly to previous calculations in the asymptotically flat case. Following standard procedures, we write the Green function, regularize the initial divergent expression by point-splitting, renormalize it by subtracting geometrical counter-terms, and take the coincidence limit in the end. After explicitly demonstrating the cancellation of the divergences and the regularity of the Green function, we express the result as a sum of two parts. One is calculated analytically and the result expressed in terms of some generalized zeta-functions, which appear in the computation of functional determinants of Laplacians on Riemann spheres. We also describe some systematic methods to evaluate these functions numerically. Interestingly, the WKB approximation naturally organizes $phi^2>$ as a series in such zeta-functions. We demonstrate this explicitly up to next-to-leading order in the WKB expansion. The other term represents the `remainder' of the WKB approximation and depends on the difference between an exact (numerical) expression and its WKB counterpart. This has to be dealt with by means of numerical approximation. The general results are specialized to the case of Schwarzschild-anti-de Sitter black hole geometries. The method is efficient enough to solve the semi-classical Einstein's equations taking into account the back-reaction from quantum fields on asymptotically anti-de Sitter black holes.

Antonino Flachi; Takahiro Tanaka

2008-03-21T23:59:59.000Z

283

Streaked x-ray spectrometer having a discrete selection of Bragg geometries for Omega  

Science Conference Proceedings (OSTI)

The streaked x-ray spectrometer (SXS) is used with streak cameras [D. H. Kalantar, P. M. Bell, R. L. Costa, B. A. Hammel, O. L. Landen, T. J. Orzechowski, J. D. Hares, and A. K. L. Dymoke-Bradshaw, in 22nd International Congress on High-Speed Photography and Photonics, edited by D. L. Paisley and A. M. Frank (SPIE, Bellingham, WA, 1997), Vol. 2869, p. 680] positioned with a ten-inch manipulator on OMEGA [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] and OMEGA EP [L. J. Waxer et al., Presented at CLEO/QELS 2008, San Jose, CA, 4-9 May 2008 (Paper JThB1)] for time-resolved, x-ray spectroscopy of laser-produced plasmas in the 1.4- to 20-keV photon-energy range. These experiments require measuring a portion of this photon-energy range to monitor a particular emission or absorption feature of interest. The SXS relies on a pinned mechanical reference system to create a discrete set of Bragg reflection geometries for a variety of crystals. A wide selection of spectral windows is achieved accurately and efficiently using this technique. It replaces the previous spectrometer designs that had a continuous Bragg angle adjustment and required a tedious alignment calibration procedure. The number of spectral windows needed for the SXS was determined by studying the spectral ranges selected by OMEGA users over the last decade. These selections are easily configured in the SXS using one of the 25 discrete Bragg reflection geometries and one of the six types of Bragg crystals, including two curved crystals.

Millecchia, M.; Regan, S. P.; Bahr, R. E.; Romanofsky, M.; Sorce, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

2012-10-15T23:59:59.000Z

284

Making Hand Geometry Verification System More Accurate Using Time Series Representation with R-K Band Learning  

E-Print Network (OSTI)

At present, applications of biometrics are rapidly increasing due to inconveniences in using traditional passwords and physical keys. Hand geometry, one of the most well-known biometrics, is implemented in many verification systems with various feature extraction methods. In recent work, a hand geometry verification system using time series conversion techniques and Dynamic Time Warping (DTW) distance measure with Sakoe-Chiba band has been proposed. This system demonstrates many advantages, especially ease of implementation and small storage space requirement using time series representation. In this paper, we propose a novel hand geometry verification system that exploits DTW distance measure and R-K band learning to further improve the system performance. Finally, our evaluation reveals that our proposed system outperforms the current system by a wide margin, in terms of False Acceptance Rate (FAR), False Rejection Rate (FRR), and Total Success Rate (TSR) at Equal Error Rate (EER).

Niennattrakul, Vit

2009-01-01T23:59:59.000Z

285

Non-Lead/Acid Battery Recyclers:  

Science Conference Proceedings (OSTI)

... in H2O solution such as Citric Acid, Acetic Acid, Acetates or ... MnO2 is soluble in sulfuric acid only at ... cells were treated by alkali followed by acids. ...

2011-08-02T23:59:59.000Z

286

NDB Site Map  

NLE Websites -- All DOE Office Websites (Extended Search)

Site map NDB Home Search Structures Search DNA Search RNA Advanced Search Nucleic acid tools RNA 3D motif atlas Non-redundant lists RNA base triples atlas WebFR3D R3D Align Contact NDB Mailing Address About NDB NDB Members Goal References Publications Site map Tools Software Standards Standard Reference Supplementary Information Ideal Geometries X-PLOR Parameters Valence Geometries RNA Ontology Consortium mmCIF Resources PDBML Resources Education Introduction to Nucleic Acids: DNA Definition of terms RNA Base Pair Families RNA Base-Phosphate Families Base Stacking Interactions Non Redundant list Equivalence classes RNA 3D Motifs Relative Frequency Introduction to Nucleic Acids: RNA Nucleic Acid Highlight (PDB): DNA DNA Polymerase Nucleosome Transfer RNA RNA Polymerase Self-splicing RNA

287

Physical modeling and numerical simulation of subcooled boiling in one- and three-dimensional representation of bundle geometry  

Science Conference Proceedings (OSTI)

Numerical simulation of subcooled boiling in one-dimensional geometry with the Homogeneous Equilibrium Model (HEM) may yield difficulties related to the very low sonic velocity associated with the HEM. These difficulties do not arise with subcritical flow. Possible solutions of the problem include introducing a relaxation of the vapor production rate. Three-dimensional simulations of subcooled boiling in bundle geometry typical of fast reactors can be performed by using two systems of conservation equations, one for the HEM and the other for a Separated Phases Model (SPM), with a smooth transition between the two models.

Bottoni, M.; Lyczkowski, R.; Ahuja, S.

1995-07-01T23:59:59.000Z

288

October 2001 NDB Newsletter  

NLE Websites -- All DOE Office Websites (Extended Search)

THE NUCLEIC ACID DATABASE NEWSLETTER THE NUCLEIC ACID DATABASE NEWSLETTER October 2001, Volume 5, Number 1 1. A Standard Reference Frame for the Description of Nucleic Acid Base-Pair Geometry Published 2. NDB Chapter in International Tables Published 1. Standard Reference Frame Published The paper "A Standard Reference Frame for the Description of Nucleic Acid Base-Pair Geometry" has been published in the Journal of Molecular Biology (2001; 313, pp. 229 - 237). This document is available from the NDB at http://ndbserver.rutgers.edu/NDB_news/ and from the Journal of Molecular Biology. The standardization of these parameters was the subject of the Tsukuba Workshop on Nucleic Acid Structure and Interactions that was organized by the NDB and the Structural Biology Centre and held at the Structural Biology Centre in Tsukuba, Japan on January 12-14, 1999. The meeting was funded by the COE program of the Science and Technology Agency, Japan and the CREST program of the Japan Science and Technology Corporation. The meeting was organized by Masashi Suzuki of the National Institute of Bioscience and Human-Technology and Helen M. Berman and Wilma K. Olson of the Nucleic Acid Database Project (supported by National Science Foundation (USA).

289

Three-dimensional tracking of cardiac catheters using an inverse geometry x-ray fluoroscopy system  

SciTech Connect

Purpose: Scanning beam digital x-ray (SBDX) is an inverse geometry fluoroscopic system with high dose efficiency and the ability to perform continuous real-time tomosynthesis at multiple planes. This study describes a tomosynthesis-based method for 3D tracking of high-contrast objects and present the first experimental investigation of cardiac catheter tracking using a prototype SBDX system. Methods: The 3D tracking algorithm utilizes the stack of regularly spaced tomosynthetic planes that are generated by SBDX after each frame period (15 frames/s). Gradient-filtered versions of the image planes are generated, the filtered images are segmented into object regions, and then a 3D coordinate is calculated for each object region. Two phantom studies of tracking performance were conducted. In the first study, an ablation catheter in a chest phantom was imaged as it was pulled along a 3D trajectory defined by a catheter sheath (10, 25, and 50 mm/s pullback speeds). SBDX tip tracking coordinates were compared to the 3D trajectory of the sheath as determined from a CT scan of the phantom after the registration of the SBDX and CT coordinate systems. In the second study, frame-to-frame tracking precision was measured for six different catheter configurations as a function of image noise level (662-7625 photons/mm{sup 2} mean detected x-ray fluence at isocenter). Results: During catheter pullbacks, the 3D distance between the tracked catheter tip and the sheath centerline was 1.0{+-}0.8 mm (mean {+-}one standard deviation). The electrode to centerline distances were comparable to the diameter of the catheter tip (2.3 mm), the confining sheath (4 mm outside diameter), and the estimated SBDX-to-CT registration error ({+-}0.7 mm). The tip position was localized for all 332 image frames analyzed and 83% of tracked positions were inside the 3D sheath volume derived from CT. The pullback speeds derived from the catheter trajectories were within 5% of the programed pullback speeds. The tracking precision of ablation and diagnostic catheter tips ranged from {+-}0.2 mm at the highest image fluence to {+-}0.9 mm at the lowest fluence. Tracking precision depended on image fluence, the size of the tracked catheter electrode, and the contrast of the electrode. Conclusions: High speed multiplanar tomosynthesis with an inverse geometry x-ray fluoroscopy system enables 3D tracking of multiple high-contrast objects at the rate of fluoroscopic imaging. The SBDX system is capable of tracking electrodes in standard cardiac catheters with approximately 1 mm accuracy and precision.

Speidel, Michael A.; Tomkowiak, Michael T.; Raval, Amish N.; Van Lysel, Michael S. [Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53705 (United States); Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States); Department of Medicine and Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin 53792 (United States)

2010-12-15T23:59:59.000Z

290

GEOMETRY, HEAT REMOVAL AND KINETICS SCOPING MODELS FOR HYDROGEN STORAGE SYSTEMS  

DOE Green Energy (OSTI)

It is recognized that detailed models of proposed hydrogen storage systems are essential to gain insight into the complex processes occurring during the charging and discharging processes. Such insight is an invaluable asset for both assessing the viability of a particular system and/or for improving its design. The detailed models, however, require time to develop and run. Clearly, it is much more efficient to begin a modeling effort with a good system design and to progress from that point. To facilitate this approach, it is useful to have simplified models that can quickly estimate optimal loading and discharge kinetics, effective hydrogen capacities, system dimensions and heat removal requirements. Parameters obtained from these models can then be input to the detailed models to obtain an accurate assessment of system performance that includes more complete integration of the physical processes. This report describes three scoping models that assess preliminary system design prior to invoking a more detailed finite element analysis. The three models address the kinetics, the scaling and heat removal parameters of the system, respectively. The kinetics model is used to evaluate the effect of temperature and hydrogen pressure on the loading and discharge kinetics. As part of the kinetics calculations, the model also determines the mass of stored hydrogen per mass of hydride (in a particular reference form). As such, the model can determine the optimal loading and discharge rates for a particular hydride and the maximum achievable loading (over an infinite period of time). The kinetics model developed with the Mathcad{reg_sign} solver, runs in a mater of seconds and can quickly be used to identify the optimal temperature and pressure for either the loading or discharge processes. The geometry scoping model is used to calculate the size of the system, the optimal placement of heat transfer elements, and the gravimetric and volumetric capacities for a particular geometric configuration and hydride. This scoping model is developed in Microsoft Excel{reg_sign} and inputs the mass of hydrogen to be stored, mass of stored hydrogen to mass of hydride (from the kinetics model), component densities, etc. The heat removal scoping model is used to calculate coolant flowrates, pressure drops and temperature increases over the length of the cooling channels. The model also calculates the convection heat transfer coefficient required to remove the heat of reaction associated with hydrogen uptake. The heat removal model inputs dimensions and the mass of hydrogen to be stored directly from the geometry scoping model. Additionally, the model inputs the heats of reaction, the thermal properties of the coolant and the time required to charge the bed.

Hardy, B

2007-11-16T23:59:59.000Z

291

Approaches to the Use of Geometry in Architecture: A study of the works of Andrea Palladio, Frank Lloyd Wright, and Frank Gehry  

E-Print Network (OSTI)

Geometry deals with form, shape, and measurement and is a part of mathematics where visual thought is dominant. Both design and construction in architecture deal with visualization, and architects constantly employ geometry. Today, with the advent of computer software, architects can visualize forms that go beyond our everyday experience. Some architects claim that the complex forms of their works have correlations with non-Euclidean geometry, but the space we experience is still Euclidean. Given this context, I have explored possible correlations that might exist between mathematical concepts of geometry and the employment of geometry in architectural design from a historic perspective. The main focus will be to describe the two phenomena historically, and then investigate any connections that might emerge from the discussion. While discussing the way geometry has been approached in architecture, I have focused on the Renaissance, Modern, and Post-modern phases as they have a distinct style and expression. Andrea Palladio, Frank Lloyd Wright, and Frank Gehry's works will be case studies for the Renaissance, Modern, and Post-modern phases respectively. One of the important conclusions of this study is that architects use geometry in a more subconscious and intuitive manner while designing. Certain approaches to geometry can be determined by the way an architect deals with form and space. From the discussions of the works of Palladio, Wright, and Gehry, it can be concluded that from a two-dimensional simple approach to form and space in architecture, there has been a development of thinking about complex forms three dimensionally. Similarly, in mathematics, geometry has developed from a two-dimensional and abstract description of our surroundings to something that can capture the complex and specific nature of a phenomena. It is also shown that architects rarely come up with new concepts of geometry. Significant developments in geometry have always been in the domain of mathematics. Hence, most correlations between geometry in architecture and geometry in mathematics develop much later than the introduction of those concepts of geometry in mathematics. It is also found that the use of Euclidean geometry persists in architecture and that later concepts like non-Euclidean geometry cannot be used in an instrumental manner in architecture.

Srinivasan, Urmila

2009-05-01T23:59:59.000Z

292

Tracking and physics validation studies of the simplified geometry description with $B^0_{(s)} \\to h^+h^{'-}$ decays  

E-Print Network (OSTI)

This note validates the usage of the simplified detector geometry description. A sample of $B^0_{(s)} \\to h^+h^{'-}$ decays was used to assess the tracking and physics performance with respect to what is obtained with the full detector description. No significant degradation of performance was found.

M. Gersabeck; E. Rodrigues

2008-08-06T23:59:59.000Z

293

LIM-G: Learner-initiating instruction model based on cognitive knowledge for geometry word problem comprehension  

Science Conference Proceedings (OSTI)

Computer-assisted instruction systems have been broadly applied to help students solve math word problem. The majority of such systems, which are based on an instructor-initiating instruction strategy, provide pre-designed problems for the learners. ... Keywords: Diagrammatic and telegraphic representation, Geometry word problem, Intelligent tutoring system, Learner-initiating instruction, Problem comprehension, Problem posing, Problem solving

Wing-Kwong Wong; Sheng-Cheng Hsu; Shih-Hung Wu; Cheng-Wei Lee; Wen-Lian Hsu

2007-05-01T23:59:59.000Z

294

GEOMETRY COMPRESSION OF TETRAHEDRAL MESHES USING OPTIMIZED Dan Chen, Yi-Jen Chiang, Nasir Memon, and Xiaolin Wu  

E-Print Network (OSTI)

GEOMETRY COMPRESSION OF TETRAHEDRAL MESHES USING OPTIMIZED PREDICTION Dan Chen, Yi-Jen Chiang author is supported in part by NSF Grant CCR-0208678. The contact author is Yi-Jen Chiang. nectivity(3):480­489, 2001. Special Issue for Eurographics '01. [2] D. Chen, Y.-J. Chiang, N. Memon, and X. Wu. Opti- mized

Chiang, Yi-Jen

295

Black holes in the Einstein -Gauss-Bonnet theory and the geometry of their thermodynamics-II  

E-Print Network (OSTI)

In the present work we study (i) charged black hole in Einstein-Gauss-Bonnet (EGB) theory, known as Einstein-Maxwell-Gauss-Bonnet (EMGB) black hole and (ii) black hole in EGB gravity with Yang-Mills field. The thermodynamic geometry of these two black hole solutions has been investigated, using the modified entropy in Gauss-Bonnet theory.

Ritabrata Biswas; Subenoy Chakraborty

2009-05-12T23:59:59.000Z

296

Fatty Acid Methods and Measurements  

Science Conference Proceedings (OSTI)

... mixtures are analyzed by either gas chromatography with ... for fatty acids, including various oils and biodiesel ... Material 3276 Carrot Extract in Oil," Anal ...

2012-10-22T23:59:59.000Z

297

Acidic gas capture by diamines  

DOE Patents (OSTI)

Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.9 moles per mole of piperazine.

Rochelle, Gary (Austin, TX); Hilliard, Marcus (Missouri City, TX)

2011-05-10T23:59:59.000Z

298

Equivariant Kaehler Geometry and Localization in the G/G Model  

E-Print Network (OSTI)

We analyze in detail the equivariant supersymmetry of the $G/G$ model. In spite of the fact that this supersymmetry does not model the infinitesimal action of the group of gauge transformations, localization can be established by standard arguments. The theory localizes onto reducible connections and a careful evaluation of the fixed point contributions leads to an alternative derivation of the Verlinde formula for the $G_{k}$ WZW model. We show that the supersymmetry of the $G/G$ model can be regarded as an infinite dimensional realization of Bismut's theory of equivariant Bott-Chern currents on K\\"ahler manifolds, thus providing a convenient cohomological setting for understanding the Verlinde formula. We also show that the supersymmetry is related to a non-linear generalization (q-deformation) of the ordinary moment map of symplectic geometry in which a representation of the Lie algebra of a group $G$ is replaced by a representation of its group algebra with commutator $[g,h] = gh-hg$. In the large $k$ limit it reduces to the ordinary moment map of two-dimensional gauge theories.

Matthias Blau; George Thompson

1994-07-07T23:59:59.000Z

299

Pore geometry in woven fiber structures: 0{degree}/90{degree} plain-weave cloth layup preform  

Science Conference Proceedings (OSTI)

Composite preform fiber architectures range from the very simple to the complex, and the extremes are typified by parallel continuous fibers and complicated three-dimensional woven structures. Subsequent processing of these preforms to produce dense composites may depend critically on the geometry of the interfiber porosity. The goal of this study is to fully characterize the structure of a 0{degree}/90{degree} cloth layup preform using x-ray tomographic microscopy (XTM). This characterization includes the measurement of intercloth channel widths and their variability, the transverse distribution of through-cloth holes, and the distribution of preform porosity. The structure of the intercloth porosity depends critically on the magnitude and direction of the offset between adjacent cloth layers. The structures observed include two-dimensional networks of open pipes linking adjacent holes, arrays of parallel one-dimensional pipes linking holes, and relatively closed channels exhibiting little structure, and these different structures would appear to offer very different resistances to gas flow through the preform. These measurements, and future measurements for different fiber architectures, will yield improved understanding of the role of preform structure on processing. {copyright} {ital 1998 Materials Research Society.}

Lee, S. [Republic of Korea Army Headquarters, Chungnam, Nonsan, Duma Namson (Republic of Korea); Stock, S.R. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia30332-0245 (United States); Butts, M.D. [Chicago Bridge and Iron, Chicago, Illinois (United States); Starr, T.L. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia30332-0245 (United States); Breunig, T.M. [Department of Restorative Dentistry, University of California, San Francisco, California94143-0758 (United States); Kinney, J.H. [Chemistry and Materials Science Department, Lawrence Livermore National Laboratory, Livermore, California94550 (United States)

1998-05-01T23:59:59.000Z

300

Geometry, analysis, and computation in mathematics and applied sciences. Final report  

SciTech Connect

Since 1993, the GANG laboratory has been co-directed by David Hoffman, Rob Kusner and Peter Norman. A great deal of mathematical research has been carried out here by them and by GANG faculty members Franz Pedit and Nate Whitaker. Also new communication tools, such as the GANG Webserver have been developed. GANG has trained and supported nearly a dozen graduate students, and at least half as many undergrads in REU projects.The GANG Seminar continues to thrive, making Amherst a site for short and long term visitors to come to work with the GANG. Some of the highlights of recent or ongoing research at GANG include: CMC surfaces, minimal surfaces, fluid dynamics, harmonic maps, isometric immersions, knot energies, foam structures, high dimensional soap film singularities, elastic curves and surfaces, self-similar curvature evolution, integrable systems and theta functions, fully nonlinear geometric PDE, geometric chemistry and biology. This report is divided into the following sections: (1) geometric variational problems; (2) soliton geometry; (3) embedded minimal surfaces; (4) numerical fluid dynamics and mathematical modeling; (5) GANG graphics and mathematical software; (6) description of the computational and visual analysis facility; and (7) research by undergraduates and GANG graduate seminar.

Kusner, R.B.; Hoffman, D.A.; Norman, P.; Pedit, F.; Whitaker, N.; Oliver, D.

1995-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Family of Finite Geometry Low-Density Parity-Check Codes for Quantum Key Expansion  

E-Print Network (OSTI)

We consider a quantum key expansion (QKE) protocol based on entanglement-assisted quantum error-correcting codes (EAQECCs). In these protocols, a seed of a previously shared secret key is used in the post-processing stage of a standard quantum key distribution protocol like the Bennett-Brassard 1984 protocol, in order to produce a larger secret key. This protocol was proposed by Luo and Devetak, but codes leading to good performance have not been investigated. We look into a family of EAQECCs generated by classical finite geometry (FG) low-density parity-check (LDPC) codes, for which very efficient iterative decoders exist. A critical observation is that almost all errors in the resulting secret key result from uncorrectable block errors that can be detected by an additional syndrome check and an additional sampling step. Bad blocks can then be discarded. We make some changes to the original protocol to avoid the consumption of the preshared key when the protocol fails. This allows us to greatly reduce the bit error rate of the key at the cost of a minor reduction in the key production rate, but without increasing the consumption rate of the preshared key. We present numerical simulations for the family of FG LDPC codes, and show that this improved QKE protocol has a good net key production rate even at relatively high error rates, for appropriate choices of these codes.

Kung-Chuan Hsu; Todd A. Brun

2013-03-07T23:59:59.000Z

302

New gravity-capillary waves at low speeds. Part 1: Linear geometries  

E-Print Network (OSTI)

When traditional linearised theory is used to study gravity-capillary waves produced by flow past an obstruction, the geometry of the object is assumed to be small in one or several of its dimensions. In order to preserve the nonlinear nature of the obstruction, asymptotic expansions in the low-Froude or low-Bond number limits can be derived, but here, the solutions invariably predict a waveless surface at every order. This is because the waves are in fact, exponentially small, and thus beyond-all-orders of regular asymptotics; their formation is a consequence of the divergence of the asymptotic series and the associated Stokes Phenomenon. By applying techniques in exponential asymptotics to this problem, we have discovered the existence of new classes of gravity-capillary waves, from which the usual linear solutions form but a special case. In this paper, we present the initial theory for deriving these waves through a study of gravity-capillary flow over a linearised step; this will be done using two approaches: in the first, we derive the surface waves using the the standard method of Fourier transforms; in the second, we derive the same result using exponential asymptotics. Ultimately, these two methods give the same result, but conceptually, they offer different insights into the study of the low-Froude, low-Bond number problem.

Philippe H. Trinh; S. Jonathan Chapman

2013-04-23T23:59:59.000Z

303

Minimal Curvature Trajectories: Riemannian Geometry Concepts for Model Reduction in Chemical Kinetics  

E-Print Network (OSTI)

In dissipative ordinary differential equation systems different time scales cause anisotropic phase volume contraction along solution trajectories. Model reduction methods exploit this for simplifying chemical kinetics via a time scale separation into fast and slow modes. The aim is to approximate the system dynamics with a dimension-reduced model after eliminating the fast modes by enslaving them to the slow ones via computation of a slow attracting manifold. We present a novel method for computing approximations of such manifolds using trajectory-based optimization. We discuss Riemannian geometry concepts as a basis for suitable optimization criteria characterizing trajectories near slow attracting manifolds and thus provide insight into fundamental geometric properties of multiple time scale chemical kinetics. The optimization criteria correspond to a suitable mathematical formulation of "minimal relaxation" of chemical forces along reaction trajectories under given constraints. We present various geometrically motivated criteria and the results of their application to three test case reaction mechanisms serving as examples. We demonstrate that accurate numerical approximations of slow invariant manifolds can be obtained.

Dirk Lebiedz; Volkmar Reinhardt; Jochen Siehr

2009-10-19T23:59:59.000Z

304

Geometry and reservoir heterogeneity of tertiary sandstones: a guide to reservoir continuity and geothermal resource development  

DOE Green Energy (OSTI)

External and internal continuity of Tertiary sandstones are controlled by various factors including structural trends, sand body geometry, and the distribution of mineral framework, matrix, and intersticies within the sand body. Except for the limits imposed by faults, these factors are largely inherited from the depositional environment and modified during sandstone compaction and cementation. Sandstone continuity affects energy exploration and production strategies. The strategies range in scope from regional to site-specific and closely parallel a sandstone hierarchy. The hierarchy includes subdivisions ranking from genetically related aquifer systems down to individual reservoirs within a fault-bounded sandstone. Volumes of individual reservoirs are 50% less to 200% more than estimated from conventional geologic mapping. In general, mapped volumes under-estimate actual volumes where faults are nonsealing and overestimate actual volumes where laterally continuous shale breaks cause reductions in porosity and permeability. Gross variations in these pore properties can be predicted on the basis of internal stratification and sandstone facies. Preliminary analyses indicate that large aquifers are found where barrier and strandplain sandstones parallel regional faults or where fluvial (meandering) channels trend normal to regional faults. Within these sand bodies, porosity and permeability are highest in large-scale crossbedded intervals and lowest in contorted, bioturbated, and small-scale ripple cross-laminated intervals.

Morton, R.A.; Ewing, T.E.

1981-01-01T23:59:59.000Z

305

Probing the Geometry and Interconnectivity of Pores in Organic Aerogels Using Hyperpolarized 129Xe NMR Spectroscopy  

SciTech Connect

Aerogels represent a class of novel open-pore materials with high surface area and nanometer pore sizes. They exhibit extremely low mass densities, low thermal conductivity, good acoustic insulation, and low dielectric constants. These materials have potential applications in catalysis, advanced separation techniques, energy storage, environmental remediation, and as insulating materials. Organic aerogels are stiffer and stronger than silica aerogels and are better insulators with higher thermal resistance. Resorcinol-Formaldehyde (RF) aerogels are typically prepared through the base-catalyzed sol-gel polymerization of resorcinol with formaldehyde in aqueous solution to produce gels, which are then dried in supercritical CO2.1,2 The [resorcinol]/ [catalyst] (R/C) ratio of the starting sol-gel solution has been determined to be the dominant factor that affects the properties of RF aerogels. Since the unique microstructures of aerogels are responsible for their unusual properties, characterizing the detailed porous structures and correlating them with the processing parameters are vital to establish rational design principles for novel organic aerogels with tailored properties. In this communication we report the first use of hyperpolarized (HP) 129Xe NMR to probe the geometry and interconnectivity of pores in RF aerogels and to correlate these with synthetic conditions. Our work demonstrates that HP 129Xe NMR is so far the only method for accurately measuring the free volume-to-surface-area (Vg/S) ratios for soft mesoporous materials without using any geometric models.

Moudrakovski, Igor L.; Wang, Li Q.; Baumann, T.; Satcher, J. H.; Exarhos, Gregory J.; Ratcliffe, C. I.; Ripmeester, J. A.

2004-04-28T23:59:59.000Z

306

Sintered Silver Joint Strength Dependence on Substrate Topography and Attachment Pad Geometry  

SciTech Connect

The sum of chemical and mechanical bonding limits the adhesive strength of die-attach and substrate-attach layers. This is also true for sintered silver joints whose development and employment are underway in the electronic packaging community. Chemical bonding is dictated by numerous parameters associated with the compatibility of the metallurgical bond of the two mating surfaces and the processing history that brings them together. However, the efficacy of mechanical bonding is likely affected by the topographies (e.g., roughness) of the two adjoined surfaces and also perhaps the shape of the attachment layer itself (e.g., circles, squares, and sizes thereof). In this study the mechanical bonding component is examined through the modification of the copper cladding surface on direct bonded copper (DBC) substrates, the shape of the silver pad attachment bonded to it, and the use of a joined 'DBC sandwich' that facilitates their study. It was found that simple employment of both surface topography control and printed pad geometry can affect and improve shear strength of silver sintered joints, and that there is logic to perhaps hybridize their effects. This is an important observation as more future attention is devoted to joining constituents with larger areas (> 100 mm2) in electronic packages.

Wereszczak, Andrew A [ORNL; Vuono, Daniel J [ORNL; Liang, Zhenxian [ORNL; Fox, Ethan E [ORNL

2012-01-01T23:59:59.000Z

307

TRIPLET: a two-dimensional, multigroup, triangular mesh, planar geometry, explicit transport code  

SciTech Connect

TRIPLET solves the two-dimensional multigroup transport equation in planar geometries by using a regular triangular mesh. Regular and adjoint, inhomogeneous and homogeneous (K/sub eff/ and eigenvalue searches) problems subject to vacuum, reflective, or source boundary conditions are solved. General anisotropic scattering ia allowed, and anisotropic distributed sources are permitted. The discrete ordinates approximation is used for the angular variables. A finite element method in which the angular flux is assumed to be given by a low-order polynomial in each triangle is used to solve the discrete ordinates equations. Angular fluxes are allowed to be discontinuous across triangle boundaries. A six-group, S/sub 2/, 1700-triangle, k/sub eff/ calculation of an EBR-II core requires about 4.4 minutes of CDC-7600 time; running times vary almost linearly with the total number of unknowns. Sources, fluxes, S/sub n/ constants, and cross sections may be read from standard interface files; flexible edit options are provided. Six scratch units and two system I/O units are required. A large bulk memory is necessary if core storage is inadequate. This program is operational on the CDC-7600, CDC-6600, and IBM- 360/195 computers. (13 figures, 13 tables) (RWR)

Reed, W.H.; Hill, T.R.; Brinkley, F.W.; Lathrop, K.D.

1973-10-01T23:59:59.000Z

308

Clustered Geometries Exploiting Quantum Coherence Effects for Efficient Energy Transfer in Light Harvesting  

E-Print Network (OSTI)

Elucidating quantum coherence effects and geometrical factors for efficient energy transfer in photosynthesis has the potential to uncover non-classical design principles for advanced organic materials. We study energy transfer in a linear light-harvesting model to reveal that dimerized geometries with strong electronic coherences within donor and acceptor pairs exhibit significantly improved efficiency, which is in marked contrast to predictions of the classical F\\"orster theory. We reveal that energy tuning due to coherent delocalization of photoexcitations is mainly responsible for the efficiency optimization. This coherence-assisted energy-tuning mechanism also explains the energetics and chlorophyll arrangements in the widely-studied Fenna-Matthews-Olson complex. We argue that a clustered network with rapid energy relaxation among donors and resonant energy transfer from donor to acceptor states provides a basic formula for constructing efficient light-harvesting systems, and the general principles revealed here can be generalized to larger systems and benefit future innovation of efficient molecular light-harvesting materials.

Qing Ai; Tzu-Chi Yen; Bih-Yaw Jin; Yuan-Chung Cheng

2013-07-22T23:59:59.000Z

309

Gamma ray burst delay times probe the geometry of momentum space  

E-Print Network (OSTI)

We study the application of the recently proposed framework of relative locality to the problem of energy dependent delays of arrival times of photons that are produced simultaneously in distant events such as gamma ray bursts. Within this framework, possible modifications of special relativity are coded in the geometry of momentum space. The metric of momentum space codes modifications in the energy momentum relation, while the connection on momentum space describes possible non-linear modifications in the laws of conservation of energy and momentum. In this paper, we study effects of first order in the inverse Planck scale, which are coded in the torsion and non-metricity of momentum space. We find that time delays of order Distance * Energies/m_p are coded in the non-metricity of momentum space. Current experimental bounds on such time delays hence bound the components of this tensor of order 1/m_p. We also find a new effect, whereby photons from distant sources can appear to arrive from angles slightly off the direction to the sources, which we call gravitational lensing. This is found to be coded into the torsion of momentum space.

Laurent Freidel; Lee Smolin

2011-03-29T23:59:59.000Z

310

Characteristics of low-energy ion beams extracted from a wire electrode geometry  

SciTech Connect

Beams of argon ions with energies less than 50 eV were extracted from an ion source through a wire electrode extractor geometry. A retarding potential energy analyzer (RPEA) was constructed in order to characterize the extracted ion beams. The single aperture RPEA was used to determine the ion energy distribution function, the mean ion energy and the ion beam energy spread. The multi-cusp hot cathode ion source was capable of producing a low electron temperature gas discharge to form quiescent plasmas from which ion beam energy as low as 5 eV was realized. At 50 V extraction potential and 0.1 A discharge current, the ion beam current density was around 0.37 mA/cm{sup 2} with an energy spread of 3.6 V or 6.5% of the mean ion energy. The maximum ion beam current density extracted from the source was 0.57 mA/cm{sup 2} for a 50 eV ion beam and 1.78 mA/cm{sup 2} for a 100 eV ion beam.

Vasquez, M. Jr.; Tokumura, S.; Kasuya, T. [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan); Maeno, S. [Novelion Systems Co. Ltd., Kyotanabe, Kyoto 610-0332 (Japan); Wada, M. [Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

2012-02-15T23:59:59.000Z

311

Geometry and material choices govern hard-rock drilling performance of PDC drag cutters.  

Science Conference Proceedings (OSTI)

Sandia National Laboratories has partnered with industry on a multifaceted, baseline experimental study that supports the development of improved drag cutters for advanced drill bits. Different nonstandard cutter lots were produced and subjected to laboratory tests that evaluated the influence of selected design and processing parameters on cutter loads, wear, and durability pertinent to the penetration of hard rock with mechanical properties representative of formations encountered in geothermal or deep oil/gas drilling environments. The focus was on cutters incorporating ultrahard PDC (polycrystalline diamond compact) overlays (i.e., diamond tables) on tungsten-carbide substrates. Parameter variations included changes in cutter geometry, material composition, and processing conditions. Geometric variables were the diamond-table thickness, the cutting-edge profile, and the PDC/substrate interface configuration. Material and processing variables for the diamond table were, respectively, the diamond particle size and the sintering pressure applied during cutter fabrication. Complementary drop-impact, granite-log abrasion, linear cutting-force, and rotary-drilling tests examined the response of cutters from each lot. Substantial changes in behavior were observed from lot to lot, allowing the identification of features contributing major (factor of 10+) improvements in cutting performance for hard-rock applications. Recent field demonstrations highlight the advantages of employing enhanced cutter technology during challenging drilling operations.

Wise, Jack LeRoy

2005-06-01T23:59:59.000Z

312

Volatility of Aqueous Acetic Acid, Formic Acid, and Sodium Acetate  

Science Conference Proceedings (OSTI)

The quality of water and steam is central to ensuring power plant component availability and reliability. A key part of developing operating cycle chemistry guidelines is an understanding of the impurity distribution between water and steam. This report examines the volatility of some of the principal cycle organic corrodents: acetic acid, formic acid, and sodium acetate.

2000-07-28T23:59:59.000Z

313

Carbonic Acid Retreatment of Biomass  

DOE Green Energy (OSTI)

This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. (1) Solidify the theoretical understanding of the binary CO{sub 2}/H{sub 2}O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. (2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. (3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. (4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. (5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic acid compared to water alone. (6) Determine optimal conditions for carbonic acid pretreatment of aspen wood. Optimal severities appeared to be in the mid range tested. ASPEN-Plus modeling and economic analysis of the process indicate that the process could be cost competitive with sulfuric acid if the concentration of solids in the pretreatment is maintained very high ({approx}50%). Lower solids concentrations result in larger reactors that become expensive to construct for high pressure applications.

Baylor university

2003-06-01T23:59:59.000Z

314

Carbonic Acid Pretreatment of Biomass  

SciTech Connect

This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic acid compared to water alone. 6) Determine optimal conditions for carbonic acid pretreatment of aspen wood. Optimal severities appeared to be in the mid range tested. ASPEN-Plus modeling and economic analysis of the process indicate that the process could be cost competitive with sulfuric acid if the concentration of solids in the pretreatment is maintained very high (~50%). Lower solids concentrations result in larger reactors that become expensive to construct for high pressure applications.

G. Peter van Walsum; Kemantha Jayawardhana; Damon Yourchisin; Robert McWilliams; Vanessa Castleberry

2003-05-31T23:59:59.000Z

315

A ACID RAIN Audrey Gibson  

E-Print Network (OSTI)

acid and nitric acid. Sunlight increases the rate of most of these reactions. Electric utility plants;Gas Natural Sources Concentration Carbon dioxide CO2 Decomposition 355 ppm Nitric oxide NO Electric, 2010 #12;Gas Non-Natural Sources Concentration Nitric oxide NO Internal Combustion (cars) 0.2 ppm

Toohey, Darin W.

316

Photochemical Studies on Xanthurenic Acid  

NLE Websites -- All DOE Office Websites (Extended Search)

Photochemical Studies on Xanthurenic Acid Photochemical Studies on Xanthurenic Acid J. E. Roberts, J. F. Wishart, L. Martinez, C. F. Chignell Photochem.Photobiol. 72, 467-471 (2000) Abstract: The tryptophan metabolite xanthurenic acid has been isolated from aged human cataractous lenses. The photophysical properties of xanthurenic acid were examined to determine if it is a potential chromophore for age-related cataractogenesis. We found that xanthurenic acid produces singlet oxygen (F*= 0.17; CD3OD) with the same efficiency as the lenticular chromophore N-formyl kynurenine and quenches singlet oxygen at a rate similar to other tryptophan metabolites (2.1 x 107 M-1 s-1; CD3OD) found in the eye. As the mechanisms of induction of cataracts may also involve redox reactions, the interactions of hydrated electrons (e-aq), the azide radical

317

Effect of nozzle orifice geometry on spray, combustion, and emission characteristics under diesel engine conditions.  

DOE Green Energy (OSTI)

Diesel engine performance and emissions are strongly coupled with fuel atomization and spray processes, which in turn are strongly influenced by injector flow dynamics. Modern engines employ micro-orifices with different orifice designs. It is critical to characterize the effects of various designs on engine performance and emissions. In this study, a recently developed primary breakup model (KH-ACT), which accounts for the effects of cavitation and turbulence generated inside the injector nozzle is incorporated into a CFD software CONVERGE for comprehensive engine simulations. The effects of orifice geometry on inner nozzle flow, spray, and combustion processes are examined by coupling the injector flow and spray simulations. Results indicate that conicity and hydrogrinding reduce cavitation and turbulence inside the nozzle orifice, which slows down primary breakup, increasing spray penetration, and reducing dispersion. Consequently, with conical and hydroground nozzles, the vaporization rate and fuel air mixing are reduced, and ignition occurs further downstream. The flame lift-off lengths are the highest and lowest for the hydroground and conical nozzles, respectively. This can be related to the rate of fuel injection, which is higher for the hydroground nozzle, leading to richer mixtures and lower flame base speeds. A modified flame index is employed to resolve the flame structure, which indicates a dual combustion mode. For the conical nozzle, the relative role of rich premixed combustion is enhanced and that of diffusion combustion reduced compared to the other two nozzles. In contrast, for the hydroground nozzle, the role of rich premixed combustion is reduced and that of non-premixed combustion is enhanced. Consequently, the amount of soot produced is the highest for the conical nozzle, while the amount of NOx produced is the highest for the hydroground nozzle, indicating the classical tradeoff between them.

Som, S.; Longman, D. E; Ramirez, A. I.; Aggarwal, S. K. (Energy Systems); (Univ. of Illinois at Chicago)

2011-03-01T23:59:59.000Z

318

Quantum field theory in curved graphene spacetimes, Lobachevsky geometry, Weyl symmetry, Hawking effect, and all that  

E-Print Network (OSTI)

We extensively discuss the theoretical framework to make curved monolayer graphene a realization of quantum field theory in curved spacetime. We rely upon a model of the electron-phonon interaction that reproduces the standard semiclassical Dirac quantum field in a curved spacetime. This model holds for very long wavelengths of the graphene conductivity electrons involved. Provided the full description of the phonon-electron interaction is of a modified gravity-type, the core of the results presented here apply, with due changes, to that case too. Using local Weyl symmetry, we probe into the possibility to reproduce a Hawking effect. For the sake of making the test easier in a laboratory, the whole study is carried out for the case of purely spatial curvatures, and for conformally flat spacetimes. Since we show that for the sphere there is no intrinsic horizon, the focus is on the infinite different surfaces of constant negative Gaussian curvature. Even though, in those cases, deep reasons of Lobachevsky geometry seem to lead to unreachable event horizons, we show under which conditions the horizon is within reach. The Hawking effect, then, takes place on the Beltrami surface. We also explicitly study the spacetimes of the other two pseudospheres, and show their relation to de Sitter, and BTZ black-hole spacetimes. In the same limit that gives a reachable event horizon, these two cases, essentially, reduce to Beltrami. This, together with the fact that all the infinite surfaces in point are applicable to either one of the three pseudospheres, make us conjecture about the possibility for a Hawking effect for a generic surface of the family. The Hawking effect here manifests itself through a finite (Hawking) temperature electronic local density of states, that we exhibit.

Alfredo Iorio; Gaetano Lambiase

2013-08-01T23:59:59.000Z

319

Catalytic Hydrogenation of Glutamic Acid  

Science Conference Proceedings (OSTI)

Technology to convert biomass to chemical building blocks provides an opportunity to displace fossil fuels and increase the economic viability of bio-refineries. Coupling fermentation capability with aqueous phase catalysis provides novel routes to monomers and chemicals, including those not accessible from petrochemical routes. Glutamic acid provides a platform to numerous compounds through thermochemical approaches including, hydrogentation, cyclyization, decarboxylation and deamination. Hydrogenation of amino acids also provides access into chiral compounds with high enantio-purity. This paper details aqueous phase hydrogenation reactions we have developed that lead to valuable chemical intermediates from glutamic acid.

Holladay, John E.; Werpy, Todd A.; Muzatko, Danielle S.

2004-05-01T23:59:59.000Z

320

PRODUCTION OF TRIFLUOROACETIC ACID COMPOUNDS  

DOE Patents (OSTI)

A process is described for the preparation of trifluoroacetic acid. Acetone vapor diluted wlth nitrogen and fluorine also diluted with nltrogen are fed separately at a temperature of about 210 deg C into a reaction vessel containing a catalyst mass selected from-the group consisting of silver and gold. The temperature in the reaction vessel is maintained in the range of 200 deg to 250 deg C. The reaction product, trifluoroacetyl fluoride, is absorbed in aqueous alkali solution. Trifluoroacetic acid is recovered from the solution by acidification wlth an acid such as sulfuric followed by steam distillation.

Haworth, W.N.; Stacey, M.

1949-08-30T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Metabolism of Thioctic Acid in Algae  

E-Print Network (OSTI)

METABOLISM OF THlOCTlC ACID IN ALGAE TWO-WEEK LOAN COPY ThisMETABOLISM OF THIOCTIC ACID IN ALGAE Hans Grisebach, R. , C.METABOLISM OF THIOCTIC ACID IN ALGAE Hans Grisebach, R. C.

Grisebach, Hans; Fuller, R.C.; Calvin, M.

1956-01-01T23:59:59.000Z

322

Bootstrap Current for the Edge Pedestal Plasma in a Diverted Tokamak Geometry  

SciTech Connect

The edge bootstrap current plays a critical role in the equilibrium and stability of the steep edge pedestal plasma. The pedestal plasma has an unconventional and difficult neoclassical property, as compared with the core plasma. It has a narrow passing particle region in velocity space that can be easily modified or destroyed by Coulomb collisions. At the same time, the edge pedestal plasma has steep pressure and electrostatic potential gradients whose scale-lengths are comparable with the ion banana width, and includes a magnetic separatrix surface, across which the topological properties of the magnetic field and particle orbits change abruptly. A driftkinetic particle code XGC0, equipped with a mass-momentum-energy conserving collision operator, is used to study the edge bootstrap current in a realistic diverted magnetic field geometry with a self-consistent radial electric field. When the edge electrons are in the weakly collisional banana regime, surprisingly, the present kinetic simulation confirms that the existing analytic expressions [represented by O. Sauter et al. , Phys. Plasmas 6 , 2834 (1999)] are still valid in this unconventional region, except in a thin radial layer in contact with the magnetic separatrix. The agreement arises from the dominance of the electron contribution to the bootstrap current compared with ion contribution and from a reasonable separation of the trapped-passing dynamics without a strong collisional mixing. However, when the pedestal electrons are in plateau-collisional regime, there is significant deviation of numerical results from the existing analytic formulas, mainly due to large effective collisionality of the passing and the boundary layer trapped particles in edge region. In a conventional aspect ratio tokamak, the edge bootstrap current from kinetic simulation can be significantly less than that from the Sauter formula if the electron collisionality is high. On the other hand, when the aspect ratio is close to unity, the collisional edge bootstrap current can be significantly greater than that from the Sauter formula. Rapid toroidal rotation of the magnetic field lines at the high field side of a tight aspect-ratio tokamak is believed to be the cause of the different behavior. A new analytic fitting formula, as a simple modification to the Sauter formula, is obtained to bring the analytic expression to a better agreement with the edge kinetic simulation results

S. Koh, C.S. Chang, S. Ku, J.E. Menard, H. Weitzner and W. Choe

2012-08-10T23:59:59.000Z

323

Nucleic acid arrays and methods of synthesis  

SciTech Connect

The present invention generally relates to high density nucleic acid arrays and methods of synthesizing nucleic acid sequences on a solid surface. Specifically, the present invention contemplates the use of stabilized nucleic acid primer sequences immobilized on solid surfaces, and circular nucleic acid sequence templates combined with the use of isothermal rolling circle amplification to thereby increase nucleic acid sequence concentrations in a sample or on an array of nucleic acid sequences.

Sabanayagam, Chandran R. (Allston, MA); Sano, Takeshi (Needham, MA); Misasi, John (Syracuse, NY); Hatch, Anson (Seattle, WA); Cantor, Charles (Del Mar, CA)

2001-01-01T23:59:59.000Z

324

Seasonalepisodic control of acid deposition  

E-Print Network (OSTI)

This report contains the climatological, technical and economic factors for episodic and seasonal control of emissions in existing power plants. Analyzing a large data set of acid deposition for the years 1982-85, we find ...

Fay, James A.

1988-01-01T23:59:59.000Z

325

Polybenzimidazole: Phosphoric Acid Fuel Cells  

NLE Websites -- All DOE Office Websites (Extended Search)

Polybenzimidazole: Phosphoric Acid Fuel Cells Speaker(s): Dave Sopchak Date: May 1, 2013 - 3:00pm - 4:00pm Location: 90-3122 Seminar HostPoint of Contact: Max Wei The PBI...

326

Controlling acid rain : policy issues  

E-Print Network (OSTI)

The policy and regulatory ramifications of U.S. acid rain control programs are examined; particularly, the alternative of a receptor-oriented strategy as constrasted to emission-oriented proposals (e.g., the Mitchell bill) ...

Fay, James A.

1983-01-01T23:59:59.000Z

327

Acidic Ion Exchange Membrane - Energy Innovation Portal  

Technology Marketing Summary In this invention we report the synthesis of a copolymer of vinyl phosphonic acid (VPA) and vinyl zirconium phosphorous (VZP) acid has ...

328

Ultra-Deep Strong Acidizing and Sour Gas Environments  

Science Conference Proceedings (OSTI)

The two acidizing environments that were studied included 10% acetic acid and a mixture of 10% acetic acid and 10% hydrochloric acid with 15 psia hydrogen...

329

Well development with acid wool  

SciTech Connect

This paper describes a unique method to prevent the lost circulation of drilling fluids in fractured bedrock aquifers. The method utilizes acid wool to bridge fractures and prevent the migration of these fluids in to the reservoir. This wool material collects the mud on its surface and allows it to be removed during development. The wool is produced from melted silic-carbonate rock and is dissolved using hydrochloric acid. The timing and methodology of installation is provided.

Hanna, T.M. (Hydrologic Consultants Inc., Lakewood, CO (USA)); Rothauge, F. (Quality Drilling Fluids Engineering Inc., Longmont, CO (USA))

1989-10-01T23:59:59.000Z

330

Acid sorption regeneration process using carbon dioxide  

DOE Patents (OSTI)

Carboxylic acids are sorbed from aqueous feedstocks onto a solid adsorbent in the presence of carbon dioxide under pressure. The acids are freed from the sorbent phase by a suitable regeneration method, one of which is treating them with an organic alkylamine solution thus forming an alkylamine-carboxylic acid complex which thermally decomposes to the desired carboxylic acid and the alkylamine.

King, C. Judson (Kensington, CA); Husson, Scott M. (Anderson, SC)

2001-01-01T23:59:59.000Z

331

MELCOR-H2 Benchmarking of the SNL Transient Sulfuric Acid Decomposition Experiments  

SciTech Connect

MELCOR is a world-renowned nuclear reactor safety analysis code that is used to simulate both light water and gas-cooled reactors. MELCOR-H2 is an extension of MELCOR that can model detailed nuclear reactors that are fully coupled with modular secondary-system components and the sulfur iodine (SI) thermochemical cycle for the generation of hydrogen and electricity. The models are applicable to both steady state and transient calculations. Previous work has shown that the hydrogen generation rate calculated by MELCOR-H2 for the SI cycle was within the expected theoretical yield, thus providing a macroscopic confirmation that MELCOR-H2's computational approach is reasonable. However, in order to better quantify its adequacy, benchmarking of the code with experimental data is required. Sulfuric acid decomposition experiments were conducted during late 2006 at Sandia National Laboratories, and MELCOR-H2 was used to simulate them. We developed an input deck based on the experiment's geometry, as well as the initial and boundary conditions, and then proceeded to compare the experimental acid conversion efficiency and SO{sub 2} production data with the code output. The comparison showed that the simulation output was typically within less than 10% of experimental data, and that key experimental data trends such as acid conversion efficiency, molar acid flow rate, and solution mole % were computed adequately by the MELCOR-H2. (authors)

Rodriguez, Sal B.; Gauntt, Randall O.; Gelbard, Fred; Pickard, Paul; Cole, Randy; McFadden, Katherine; Drennen, Tom; Martin, Billy [Sandia National Laboratories, P.O. Box 5800, MS 0748, Albuquerque, NM 87185-0748 (United States); Louie, David; Archuleta, Louis [OMICRON Safety and Risk (United States); Revankar, Shripad T. [Purdue University (United States); Vierow, Karen [University of Texas A and M (United States); El-Genk, Mohamed; Tournier, Jean Michel [University of New Mexico (United States)

2007-07-01T23:59:59.000Z

332

13th ACM Symposium on Computational Geometry, Nice, France, June 1997. The Area Bisectors of a Polygon and Force Equilibria in  

E-Print Network (OSTI)

13th ACM Symposium on Computational Geometry, Nice, France, June 1997. The Area Bisectors, and in part by the Air Force O ce of Sponsored Research, the Mathematical Sciences Institute, Intel

333

Testing the space-time geometry around black hole candidates with the available radio and X-ray data  

E-Print Network (OSTI)

Astrophysical black hole candidates are thought to be the Kerr black holes predicted by General Relativity, but the actual nature of these objects has still to be proven. The Kerr black hole hypothesis can be tested by observing strong gravity features and check if they are in agreement with the predictions of General Relativity. In particular, the study of the properties of the electromagnetic radiation emitted by the gas of the accretion disk can provide information on the geometry of the space-time around these objects and constrain possible deviations from the Kerr background.

Cosimo Bambi

2013-01-03T23:59:59.000Z

334

A casting and imaging technique for determining void geometry and relative permeability behavior of a single fracture specimen  

DOE Green Energy (OSTI)

A casting technique has been developed for making translucent replicas of the void space of natural rock fractures. Attenuation of light shined through the cast combined with digital image analysis provides a pointwise definition of fracture apertures. The technique has been applied to a fracture specimen from Dixie Valley, Nevada, and the measured void space geometry has been used to develop theoretical predictions of two-phase relative permeability. A strong anisotropy in relative permeabilities has been found, which is caused by highly anisotropic spatial correlations among fracture apertures. 16 refs., 6 figs.

Cox, B.L.; Pruess, K.; Persoff, P.

1990-01-01T23:59:59.000Z

335

Method for production of petroselinic acid and OMEGA12 hexadecanoic acid in transgenic plants  

DOE Patents (OSTI)

The present invention relates to a process for producing lipids containing the fatty acid petroselinic acid in plants. The production of petroselinic acid is accomplished by genetically transforming plants which do not normally accumulate petroselinic acid with a gene for a .omega.12 desaturase from another species which does normally accumulate petroselinic acid.

Ohlrogge, John B. (Okemos, MI); Cahoon, Edgar B. (Lansing, MI); Shanklin, John (Upton, NY); Somerville, Christopher R. (Okemos, MI)

1995-01-01T23:59:59.000Z

336

Method for production of petroselinic acid and OMEGA12 hexadecanoic acid in transgenic plants  

DOE Patents (OSTI)

The present invention relates to a process for producing lipids containing the fatty acid, petroselinic acid, in plants. The production of petroselinic acid is accomplished by genetically transforming plants which do not normally accumulate petroselinic acid with a gene for a {omega}12 desaturase from another species which does normally accumulate petroselinic acid. 19 figs.

Ohlrogge, J.B.; Cahoon, E.B.; Shanklin, J.; Somerville, C.R.

1995-07-04T23:59:59.000Z

337

Development of a Rhesus Monkey Lung Geometry Model and Application to Particle Deposition in Comparison to Humans  

SciTech Connect

The exposure-dose-response characterization of an inhalation hazard established in an animal species needs to be translated to an equivalent characterization in humans relative to comparable doses or exposure scenarios. Here, the first geometry model of the conducting airways for rhesus monkeys is developed based upon CT images of the conducting airways of a 6-month-old male, rhesus monkey. An algorithm was developed for adding the alveolar region airways using published rhesus morphometric data. The resultant lung geometry model can be used in mechanistic particle or gaseous dosimetry models. Such dosimetry models require estimates of the upper respiratory tract volume of the animal and the functional residual capacity, as well as of the tidal volume and breathing frequency of the animal. The relationship of these variables to rhesus monkeys of differing body weights was established by synthesizing and modeling published data as well as modeling pulmonary function measurements on 121 rhesus control animals. Deposition patterns of particles up to 10 ?m in size were examined for endotracheal and and up to 5 ?m for spontaneous breathing in infant and young adult monkeys and compared to those for humans. Deposition fraction of respirable size particles was found to be higher in the conducting airways of infant and young adult rhesus monkeys compared to humans. Due to the filtering effect of the conducting airways, pulmonary deposition in rhesus monkeys was lower than that in humans. Future research areas are identified that would either allow replacing assumptions or improving the newly developed lung model.

Asgharian, Bahman; Price, Owen; McClellan, Gene; Corley, Richard A.; Einstein, Daniel R.; Jacob, Rick E.; Harkema, Jack R.; Carey, Stephen A.; Schelegle, Edward; Hyde, D.; Kimbell, Julia; Miller, Frederick J.

2012-11-01T23:59:59.000Z

338

Full surface local heat transfer coefficient measurements in a model of an integrally cast impingement cooling geometry  

SciTech Connect

Cast impingement cooling geometries offer the gas turbine designer higher structural integrity and improved convective cooling when compared to traditional impingement cooling systems, which rely on plate inserts. In this paper, it is shown that the surface that forms the jets contributes significantly to the total cooling. Local heat transfer coefficient distributions have been measured in a model of an engine wall cooling geometry using the transient heat transfer technique. The method employs temperature-sensitive liquid crystals to measure the surface temperature of large-scale perspex models during transient experiments. Full distributions of local Nusselt number on both surfaces of the impingement plate, and on the impingement target plate, are presented at engine representative Reynolds numbers. The relative effects of the impingement plate thermal boundary condition and the coolant supply temperature on the target plate heat transfer have been determined by maintaining an isothermal boundary condition at the impingement plate during the transient tests. The results are discussed in terms of the interpreted flow field.

Gillespie, D.R.H.; Wang, Z.; Ireland, P.T. [Univ. of Oxford (United Kingdom). Dept. of Engineering Science; Kohler, S.T. [Rolls Royce, Bristol (United Kingdom)

1998-01-01T23:59:59.000Z

339

Exit blade geometry and part-load performance of small axial flow propeller turbines: An experimental investigation  

Science Conference Proceedings (OSTI)

A detailed experimental investigation of the effects of exit blade geometry on the part-load performance of low-head, axial flow propeller turbines is presented. Even as these turbines find important applications in small-scale energy generation using micro-hydro, the relationship between the layout of blade profile, geometry and turbine performance continues to be poorly characterized. The experimental results presented here help understand the relationship between exit tip angle, discharge through the turbine, shaft power, and efficiency. The modification was implemented on two different propeller runners and it was found that the power and efficiency gains from decreasing the exit tip angle could be explained by a theoretical model presented here based on classical theory of turbomachines. In particular, the focus is on the behaviour of internal parameters like the runner loss coefficient, relative flow angle at exit, mean axial flow velocity and net tangential flow velocity. The study concluded that the effects of exit tip modification were significant. The introspective discussion on the theoretical model's limitation and test facility suggests wider and continued experimentation pertaining to the internal parameters like inlet vortex profile and exit swirl profile. It also recommends thorough validation of the model and its improvement so that it can be made capable for accurate characterization of blade geometric effects. (author)

Singh, Punit; Nestmann, Franz [Institute for Water and River Basin Management (IWG), University of Karlsruhe, Kaiser Str. 12, D 76128 Karlsruhe (Germany)

2010-09-15T23:59:59.000Z

340

Advances in Conjugated Linoleic Acid Research, Volume 3Chapter 3 Syntheses of Conjugated Linoleic Acids  

Science Conference Proceedings (OSTI)

Advances in Conjugated Linoleic Acid Research, Volume 3 Chapter 3 Syntheses of Conjugated Linoleic Acids Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry Press Downloadable pdf...

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Advances in Conjugated Linoleic Acid Research, Volume 3 Chapter 9 Conjugated Linoleic Acid in Hypertension  

Science Conference Proceedings (OSTI)

Advances in Conjugated Linoleic Acid Research, Volume 3 Chapter 9 Conjugated Linoleic Acid in Hypertension Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry Press Downloadable pdf...

342

Advances in Conjugated Linoleic Acid Research, Volume 3Chapter 1 Conjugated Linoleic Acid Synthesis  

Science Conference Proceedings (OSTI)

Advances in Conjugated Linoleic Acid Research, Volume 3 Chapter 1 Conjugated Linoleic Acid Synthesis Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry Press Downloadable pdf...

343

Failure Analysis With a New Tool Geometry, X-Die, in Areas With High Tension/Compression Strains  

SciTech Connect

Sheet-metal forming involves a complex strain distribution over the part. The strains consist of tension, compression, and a mix of both. A geometry has been developed, the X-Die, in order to gain insight into the strain behavior of different materials. The X-Die enables strain paths far into the tension/compression region, thus creating the possibility to extend the experimental base both for definition and for further extrapolation of the Forming Limit Curve (FLC) in the tension/compression region, as well as to evaluate FE-simulation results for the same region.Today, evaluation of cracks is made by using FLC. In the conventional test methods, the strains only reach 40% compression (true strain) and often much lower percentages. In conventional test methods, the FLC for any region beyond these levels is extrapolated from existing data.The experimental test proposed in this work consists of a geometry, the X-die, which has shown that rates of 70% tension/compression can be reached (point 0.7/-0.7 in the FLC). Thereby, the region for prediction of cracks on the compression side can be extended in the Forming Limit Diagram (FLD). Furthermore, the strain paths are easy to follow and the limits when cracks appear can be evaluated. Furthermore, the experimental results show that the behavior depends on the material quality. Qualities such as Extreme High Strength Steel (EHSS) and Aluminum have a limited tension/compression rate due to failure in plane strain tension. Material qualities with high r-values, e.g. Mild steel and High Strength Steel (HSS), reach high tension/compression rates before failure and have regions with clearly defined strain signatures. This will be favorable for comparison with numerical simulations, especially for strain signatures in the tension/compression region. Furthermore, the experiments did not indicate any limitation in the compression region besides the one defined in the normal procedure in creation of an FLC.This geometry is favorable to calibrate simulation results, in order to analyze prediction of strains located on the left side in an FLD.

Andersson, Alf [Volvo Cars Body Components, 293 80 Olofstroem (Sweden); Lund University, 221 00 Lund (Sweden); Thilderkvist, Per [Industrial Development Center, 293 38 Olofstroem (Sweden)

2007-05-17T23:59:59.000Z

344

Why Sequence Algae from Acidic Waters  

NLE Websites -- All DOE Office Websites (Extended Search)

Sequence Algae from Acidic Waters? Strains of green algae from isolated acidic waters are being sequenced to understand how they adapt to variable levels of carbon dioxide, as well...

345

Recovery of mercury from acid waste residues  

DOE Patents (OSTI)

Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and thence quenching the reactivity of the nitric acid prior to nitration of the mercury metal. 1 fig.

Greenhalgh, W.O.

1987-02-27T23:59:59.000Z

346

trans Fatty Acid Content Laboratory Proficiency Program  

Science Conference Proceedings (OSTI)

Lab Proficiency Testing service for trans fatty acid content. Samples include non-hydrogenated Soybean Oil and hydrogenated Soybean Oil. trans Fatty Acid Content Laboratory Proficiency Program Laboratory Proficiency Program (LPP) aocs applicants certifie

347

Recovery of mercury from acid waste residues  

DOE Patents (OSTI)

Mercury can be recovered from nitric acid-containing fluids by reacting the fluid with aluminum metal to produce mercury metal, and then quenching the reactivity of the nitric acid prior to nitration of the mercury metal.

Greenhalgh, Wilbur O. (Richland, WA)

1989-01-01T23:59:59.000Z

348

Fuel cell electrolyte membrane with acidic polymer  

DOE Patents (OSTI)

An electrolyte membrane is formed by an acidic polymer and a low-volatility acid that is fluorinated, substantially free of basic groups, and is either oligomeric or non-polymeric.

Hamrock, Steven J. (Stillwater, MN); Larson, James M. (Saint Paul, MN); Pham, Phat T. (Little Canada, MN); Frey, Matthew H. (Cottage Grove, MN); Haugen, Gregory M. (Edina, MN); Lamanna, William M. (Stillwater, MN)

2009-04-14T23:59:59.000Z

349

acid  

Office of Legacy Management (LM)

cut into the Pajarito Plateau in north- central New Mexico. From 1943 to 1964, during nuclear weapons research activities at the Los Alamos National Laboratory (LANL, then...

350

Recovery of boric acid from ion exchangers  

DOE Patents (OSTI)

The recovery of boric acid from an anion exchange resin is improved by eluting the boric acid with an aqueous solution of ammonium bicarbonate. The boric acid can be readily purified and concentrated by distilling off the water and ammonium bicarbonate. This process is especially useful for the recovery of boric acid containing a high percentage of .sup.10 B which may be found in some nuclear reactor coolant solutions.

Pollock, Charles W. (Richland, WA)

1976-01-01T23:59:59.000Z

351

Conversion of Levulinic Acid to Methyl Tetrahydrofuran ...  

Search PNNL. PNNL Home; About; Research; Publications; Jobs; News; Contacts; Conversion of Levulinic Acid to Methyl Tetrahydrofuran. Battelle ...

352

Production of high molecular weight polylactic acid  

DOE Patents (OSTI)

A degradable high molecular weight poly(lactic acid) is described. The poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

Bonsignore, P.V.

1995-11-28T23:59:59.000Z

353

Production of high molecular weight polylactic acid  

DOE Patents (OSTI)

A degradable high molecular weight poly(lactic acid). A poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

Bonsignore, Patrick V. (Joilet, IL)

1995-01-01T23:59:59.000Z

354

NITRIC ACID RECPVERY FROM WASTE COLUTIONS  

DOE Patents (OSTI)

The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acids ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of rutheniuim.

Wilson, A.S.

1959-04-14T23:59:59.000Z

355

NITRIC ACID RECOVERY FROM WASTE SOLUTIONS  

DOE Patents (OSTI)

The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acid, ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of ruthenium.

Wilson, A.S.

1959-04-14T23:59:59.000Z

356

Conversion of Levulinic Acid to Methyl Tetrahydrofuran ...  

Biomass and Biofuels Conversion of Levulinic Acid to Methyl Tetrahydrofuran Pacific Northwest National Laboratory. Contact PNNL About This Technology ...

357

Synthesis of an acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters  

DOE Patents (OSTI)

A process is disclosed for preparing an acid addition salt of delta-aminolevulinic acid comprising. The process involves dissolving a lower alkyl 5-bromolevulinate and an alkali metal diformylamide in an organic solvent selected from the group consisting of acetonitrile, methanol, tetrahydrofuran, 2-methyltetrahydrofuran and methylformate or mixtures to form a suspension of an alkyl 5-(N,N-diformylamino) levulinate ester; and hydrolyzing the alkyl 5-(N,N-diformylamino) levulinate with an inorganic acid to form an acid addition salt of delta-amino levulinic acid.

Moens, L.

1999-05-25T23:59:59.000Z

358

NGC 5548: The AGN Energy Budget Problem and the Geometry of the Broad-Line Region and Torus  

E-Print Network (OSTI)

We consider in detail the spectral energy distribution (SED) and multi-wavelength variability of NGC5548. Comparison with the SEDs of other AGNs implies that the internal reddening of NGC5548 is E(B-V) = 0.17 mag. The extinction curve is consistent with the mean curve of other AGNs found by Gaskell & Benker, but inconsistent with an SMC-type reddening curve. Because most IR emission originates exterior to the broad-line region (BLR), the SED seen by the inner BLR is different from that seen by the outer BLR and from the earth. The most likely BLR covering factor is ~ 40% and it is not possible to get an overall BLR covering factor of less than 20%. This requires that the BLR is not spherically symmetric and that we are viewing through a hole. Line-continuum variability transfer functions are consistent with this geometry. The covering factor and geometry imply that near the equatorial plane the BLR covering approaches 100%. The spectrum seen by the outer regions of the BLR and by the torus is thus modified by the absorption in the inner BLR. This shielding solves the problem of observed BLR ionization stratification being much greater than implied by photoionization models. The BLR obscuration also removes the problem of the torus covering factor being greater than the BLR covering factor, and gives consistency with the observed fraction of obscured AGNs. The flux reduction at the torus also reduces the problem of AGN dust-reverberation lags giving sizes smaller than the dust-sublimation radii.

C. Martin Gaskell; Elizabeth S. Klimek; Ludmila S. Nazarova

2007-11-07T23:59:59.000Z

359

The Catalytic Scaffold fo the Haloalkanoic Acid Dehalogenase Enzyme Superfamily Acts as a Mold for the Trigonal Bipyramidal Transition State  

Science Conference Proceedings (OSTI)

The evolution of new catalytic activities and specificities within an enzyme superfamily requires the exploration of sequence space for adaptation to a new substrate with retention of those elements required to stabilize key intermediates/transition states. Here, we propose that core residues in the large enzyme family, the haloalkanoic acid dehalogenase enzyme superfamily (HADSF) form a 'mold' in which the trigonal bipyramidal transition states formed during phosphoryl transfer are stabilized by electrostatic forces. The vanadate complex of the hexose phosphate phosphatase BT4131 from Bacteroides thetaiotaomicron VPI-5482 (HPP) determined at 1.00 Angstroms resolution via X-ray crystallography assumes a trigonal bipyramidal coordination geometry with the nucleophilic Asp-8 and one oxygen ligand at the apical position. Remarkably, the tungstate in the complex determined to 1.03 Angstroms resolution assumes the same coordination geometry. The contribution of the general acid/base residue Asp-10 in the stabilization of the trigonal bipyramidal species via hydrogen-bond formation with the apical oxygen atom is evidenced by the 1.52 Angstroms structure of the D10A mutant bound to vanadate. This structure shows a collapse of the trigonal bipyramidal geometry with displacement of the water molecule formerly occupying the apical position. Furthermore, the 1.07 Angstroms resolution structure of the D10A mutant complexed with tungstate shows the tungstate to be in a typical 'phosphate-like' tetrahedral configuration. The analysis of 12 liganded HADSF structures deposited in the protein data bank (PDB) identified stringently conserved elements that stabilize the trigonal bipyramidal transition states by engaging in favorable electrostatic interactions with the axial and equatorial atoms of the transferring phosphoryl group.

Lu,Z.; Dunaway-Mariano, D.; Allen, K.

2008-01-01T23:59:59.000Z

360

Bond-valence methods for pKa prediction. II. Bond-valence, electrostatic, molecular geometry, and solvation effects  

DOE Green Energy (OSTI)

In a previous contribution, we outlined a method for predicting (hydr)oxy-acid and oxide surface acidity constants based on three main factors: bond valence, Me?O bond ionicity, and molecular shape. Here electrostatics calculations and ab initio molecular dynamics simulations are used to qualitatively show that Me?O bond ionicity controls the extent to which the electrostatic work of proton removal departs from ideality, bond valence controls the extent of solvation of individual functional groups, and bond valence and molecular shape controls local dielectric response. These results are consistent with our model of acidity, but completely at odds with other methods of predicting acidity constants for use in multisite complexation models. In particular, our ab initio molecular dynamics simulations of solvated monomers clearly indicate that hydrogen bonding between (hydr)oxo-groups and water molecules adjusts to obey the valence sum rule, rather than maintaining a fixed valence based on the coordination of the oxygen atom as predicted by the standard MUSIC model.

Bickmore, Barry R.; Rosso, Kevin M.; Tadanier, Christopher J.; Bylaska, Eric J.; Doud, Darrin

2006-08-15T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Hydrogenation using hydrides and acid  

DOE Patents (OSTI)

The present invention relates to a very rapid, non-catalytic process for hydrogenating unsaturated organic compounds that can be carried out at temperatures generally lower than previously utilized. In this process organic compounds which contain at least one reducible functional group are hydrogenated non-catalytically by reacting them with a hydride complex and a strong acid. The reducible functional group may be, for example, C=C, C-OH, C-O-C, or a strained cyclic structure. If the reactants are not mutually soluble, they are dissolved in an appropriate inert solvent. 3 tabs.

Bullock, R.M.

1989-12-13T23:59:59.000Z

362

(Acidic deposition and the environment)  

Science Conference Proceedings (OSTI)

The travelers presented several papers at the Fourth International Conference on Acidic Deposition. These covered the following topics: atmospheric chemistry and deposition of airborne nitrogen compounds, soil solution chemistry in high-elevation spruce forests, and forest throughfall measurements for estimating total sulfur deposition to ecosystems. In addition, S. E. Lindberg was invited to organize and chair a conference session on Throughfall and Stemflow Experiments, and to present an invited lecture on Atmospheric Deposition and Canopy Interactions of Metals and Nitrogen in Forest Ecosystems: The Influence of Global Change'' at the 110th Anniversary Celebration of the Free University of Amsterdam.

Garten, C.T.; Lindberg, S.E.; Van Miegroet, H.

1990-10-24T23:59:59.000Z

363

Development of an Amino Acid (in Solution) Standard ...  

Science Conference Proceedings (OSTI)

Development of an Amino Acid (in Solution) Standard Reference Material. Summary: Amino acids are the sequential components ...

2013-03-13T23:59:59.000Z

364

LITERATURE REVIEW OF BORIC ACID SOLUBILITY DATA  

SciTech Connect

A new solvent system is being evaluated for use in the Modular Caustic-Side Solvent Extraction Unit (MCU) and in the Salt Waste Processing Facility (SWPF). The new system replaces the current dilute nitric acid strip solution with 0.01 M boric acid. This literature study is performed to determine if there is a potential for boric acid to crystallize in the lines with emphasis on the transfer lines to the Defense Waste Processing Facility. This report focuses on the aqueous phase chemistry of boric acid under conditions relevant to MCU and SWPF. Operating and transfer conditions examined for the purpose of this review include temperatures between 13 C (McLeskey, 2008) and 45 C (Fondeur, 2007) and concentrations from 0 to 3M in nitric acid as well as exposure of small amounts of entrained boric acid in the organic phase to the sodium hydroxide caustic wash stream. Experiments were also conducted to observe any chemical reactions and off-gas generation that could occur when 0.01 M boric acid solution mixes with 3 M nitric acid solution and vice versa. Based on the low concentration (0.01M) of boric acid in the MCU/SWPF strip acid and the moderate operating temperatures (13 C to 45 C), it is unlikely that crystallization of boric acid will occur in the acid strip solution under process or transfer conditions. Mixing experiments of boric and nitric acid show no measurable gas generation (< 1 cc of gas per liter of solution) under similar process conditions.

Crapse, K.; Kyser, E.

2011-09-22T23:59:59.000Z

365

Automation of pattern recognition and fractal-geometry-based pattern quantification, exemplified by mineral-phase distribution patterns in igneous rocks  

Science Conference Proceedings (OSTI)

This study analyses the possibility of accurate quantification of automatically digitized mineral-phase distribution patterns in igneous rocks. Based on their colour contrast, different minerals were manually and automatically digitized on micro to macro ... Keywords: Box-counting, Fabric inhomogeneity, Fabric quantification, Fractal geometry, Granite

Mark Peternell; Jrn H. Kruhl

2009-07-01T23:59:59.000Z

366

Enabling In Situ Pre- and Post-processing for Exascale Hemodynamic Simulations - A Co-design Study with the Sparse Geometry Lattice-Boltzmann Code HemeLB  

Science Conference Proceedings (OSTI)

Today's fluid simulations deal with complex geometries and numerical data on an extreme scale. As computation approaches the exascale, it will no longer be possible to write and store the full-sized data set. \\textit{In situ} data analysis and scientific ...

Fang Chen, Markus Flatken, Achim Basermann, Andreas Gerndt, James Hetheringthon, Timm Kruger, Gregor Matura, Rupert W. Nash

2012-11-01T23:59:59.000Z

367

The DW/QFT correspondence It has been known for some time that the geometry of a large class of p-branes interpo-  

E-Print Network (OSTI)

Chapter 3 The DW/QFT correspondence It has been known for some time that the geometry of a large constant [113]. The developments above inspired the authors of [114] to conjecture a DW/QFT cor invariance forms an obstruction for making quantitative checks on the DW/QFT correspondence in this case

Groningen, Rijksuniversiteit

368

Self-assembling multimeric nucleic acid constructs  

DOE Patents (OSTI)

The invention is directed to constructs and compositions containing multimeric forms of nucleic acid. Multimeric nucleic acids comprise single-stranded nucleic acids attached via biotin to streptavidin and bound with a functional group. These constructs can be utilized in vivo to treat or identify diseased tissue or cells. Repeated administrations of multimeric nucleic acid compositions produce a rapid and specific amplification of nucleic acid constructs and their attached functional groups. For treatment purposes, functional groups may be toxins, radioisotopes, genes or enzymes. Diagnostically, labeled multimeric constructs may be used to identify specific targets in vivo or in vitro. Multimeric nucleic acids may also be used in nanotechnology and to create self-assembling polymeric aggregates such as membranes of defined porosity, microcircuits and many other products. 5 figs.

Cantor, C.R.; Niemeyer, C.M.; Smith, C.L.; Sano, Takeshi; Hnatowich, D.J.; Rusckowski, M.

1996-10-01T23:59:59.000Z

369

Self-assembling multimeric nucleic acid constructs  

DOE Patents (OSTI)

The invention is directed to constructs and compositions containing multimeric forms of nucleic acid. Multimeric nucleic acids comprise single-stranded nucleic acids attached via biotin to streptavidin and bound with a functional group. These constructs can be utilized in vivo to treat or identify diseased tissue or cells. Repeated administrations of multimeric nucleic acid compositions produce a rapid and specific amplification of nucleic acid constructs and their attached functional groups. For treatment purposes, functional groups may be toxins, radioisotopes, genes or enzymes. Diagnostically, labeled multimeric constructs may be used to identify specific targets in vivo or in vitro. Multimeric nucleic acids may also be used in nanotechnology and to create self-assembling polymeric aggregates such as membranes of defined porosity, microcircuits and many other products.

Cantor, Charles R. (Boston, MA); Niemeyer, Christof M. (Bremen, DE); Smith, Cassandra L. (Boston, MA); Sano, Takeshi (Boston, MA); Hnatowich, Donald J. (Brookline, MA); Rusckowski, Mary (Southborough, MA)

1996-01-01T23:59:59.000Z

370

Self-assembling multimeric nucleic acid constructs  

DOE Patents (OSTI)

The invention is directed to constructs and compositions containing multimeric forms of nucleic acid. Multimeric nucleic acids comprise single-stranded nucleic acids attached via biotin to streptavidin and bound with a functional group. These constructs can be utilized in vivo to treat or identify diseased tissue or cells. Repeated administrations of multimeric nucleic acid compositions produce a rapid and specific amplification of nucleic acid constructs and their attached functional groups. For treatment purposes, functional groups may be toxins, radioisotopes, genes or enzymes. Diagnostically, labeled multimeric constructs may be used to identify specific targets in vivo or in vitro. Multimeric nucleic acids may also be used in nanotechnology and to create self-assembling polymeric aggregates such as membranes of defined porosity, microcircuits and many other products.

Cantor, Charles R. (Boston, MA); Niemeyer, Christof M. (Bremen, DE); Smith, Cassandra L. (Boston, MA); Sano, Takeshi (Boston, MA); Hnatowich, Donald J. (Brookline, MA); Rusckowski, Mary (Southborough, MA)

1999-10-12T23:59:59.000Z

371

Spontaneous wrinkling in azlactone-based functional polymer thin films in 2D and 3D geometries for guided nanopatterning  

Science Conference Proceedings (OSTI)

We report a simple, one step process for developing wrinkling patterns in azlactone-based polymer thin films and brushes in 2D and 3D surfaces. The polymer used in this work wrinkles spontaneously upon deposition and solidification on a substrate without applying any external strain to the substrate, with the mode of deposition defining the direction of the wrinkles. Wrinkle formation is shown to occur on a variety of substrates over large areas. We also find that a very thin brush-like layer of an azlactone-containing block copolymer also exhibits wrinkled topology. Given the spontaneity and versatility of wrinkle formation, we further demonstrate two proofs-of-concept, i) that these periodic wrinkled structures are not limited to planar surfaces, but are also developed in complex geometries including tubes, cones and other 3D structures; and ii) that this one-step wrinkling process can be used to guide the deposition of metal nanoparticles and quantum dots, creating a periodic, nanopatterned film.

Ramanathan, Nathan Muruganathan [ORNL; Lokitz, Bradley S [ORNL; Messman, Jamie M [ORNL; Stafford, Christopher M [National Institute of Standards and Technology (NIST); Kilbey, II, S Michael [ORNL

2013-01-01T23:59:59.000Z

372

A Local Incident Flux Response Expansion Transport Method for Coupling to the Diffusion Method in Cylindrical Geometry  

SciTech Connect

A local incident flux response expansion transport method is developed to generate transport solutions for coupling to diffusion theory codes regardless of their solution method (e.g., fine mesh, nodal, response based, finite element, etc.) for reactor core calculations in both two-dimensional (2-D) and three-dimensional (3-D) cylindrical geometries. In this approach, a Monte Carlo method is first used to precompute the local transport solution (i.e., response function library) for each unique transport coarse node, in which diffusion theory is not valid due to strong transport effects. The response function library is then used to iteratively determine the albedo coefficients on the diffusion-transport interfaces, which are then used as the coupling parameters within the diffusion code. This interface coupling technique allows a seamless integration of the transport and diffusion methods. The new method retains the detailed heterogeneity of the transport nodes and naturally constructs any local solution within them by a simple superposition of local responses to all incoming fluxes from the contiguous coarse nodes. A new technique is also developed for coupling to fine-mesh diffusion methods/codes. The local transport method/module is tested in 2-D and 3-D pebble-bed reactor benchmark problems consisting of an inner reflector, an annular fuel region, and a controlled outer reflector. It is found that the results predicted by the transport module agree very well with the reference fluxes calculated directly by MCNP in both benchmark problems.

Dingkang Zhang; Farzad Rahnema; Abderrafi M. Ougouag

2013-09-01T23:59:59.000Z

373

HYDROGEN CHEMISORPTION ON Pt SINGLE CRYSTAL SURFACES IN ACIDIC SOLUTIONS  

DOE Green Energy (OSTI)

Hydrogen chemisorption from dilute acidic solution onto Pt single crystal surfaces was examined using an electrochemical cell directly coupled to LEED/Auger analytical system. No pre-anodization was used prior to observing hydrogen adsorption by cyclic voltammetry so that clean surfaces having the ordered structures indicated by LEED were studied. The problem of contributions from non-ordered parts of the electrode like support wires and edges was solved by using a gold evaporation masking technique. The specific contribution of atomic imperfections to the voltammetry curve was deduced from the ordered and countable imperfections occurring on high Miller index single crystal surfaces that have a stepped structure. The H-Pt bond energy Has found to be structure sensitive, and sensitive both to local site geometry and long range order in the surface. The bond strength was found to vary systematically: n(111)x(100) > (100) > n(111)x(111) > (110) > (111). Distinct states for hydrogen at steps versus hydrogen on terraces could be distinguished. The (110) surface is shown to be a (111) vicinal, probably the [3(111) x 2(111)] microfacetted surface. The zero coverage heat of adsorption on the well-ordered (111) surface (48 kJ/mol) in solutions is the same as the value reported by Ertl and co-workers for adsorption on a (111) surface in vacuum. Adsorption Isotherms for hydrogen on the (111) and (100) surfaces is adequately fit by the classical model for immobile adsorption at single sites with nearest neighbor repulsive interaction.

Ross, Jr., Philip N.

1980-04-01T23:59:59.000Z

374

Nucleic Acid Standards - Refinement Parameters  

NLE Websites -- All DOE Office Websites (Extended Search)

Refinement Parameters Refinement Parameters The DNA/RNA topology and parameter files for X-PLOR are shown below. These were tested with DNA structures and with protein-DNA complexes. X-PLOR topology file X-PLOR parameter files: X-PLOR parameter file For the refinement of high resolution structures (< 1.7 Angstroms) the parameter file with distinct bond distances and bond angles for both C2'-endo and C3'-endo conformations should be considered: X-PLOR parameter file for high resolution structures "New Parameters for the Refinement of Nucleic Acid Containing Structures." Gary Parkinson, Jaroslav Vojtechovsky, Lester Clowney, Axel Brunger*, and Helen M. Berman. (1996) Acta Cryst. D 52, 57-64 Rutgers University, Department of Chemistry, Piscataway, NJ 08855-0939; *The Howard Hughes Medical Institute and Departments of Molecular and

375

A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid  

E-Print Network (OSTI)

A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic200X An alternative biomass-based route to aromatics isaromatic compounds from biomass resources could provide a

Arceo, Elena

2011-01-01T23:59:59.000Z

376

Biorenewable Process to Acrylic Acid - PNNL: Available ...  

Acrylic acid is commonly used in the production of consumer products. Highly notable is its use in producing super absorbent polymers, the component ...

377

Available Technologies: Enhancing Fatty Acid Production by ...  

Synthetic biology has opened the door to fatty acid production from simple carbon sources through engineering microbes such as E. coil or yeast.

378

Effects of Weldment Geometry  

Science Conference Proceedings (OSTI)

Table 5   Essential differences between fatigue crack initiation sites...fusion and that stops may involve

379

Advances in Conjugated Linoleic Acid Research, Vol 2Chapter 15 Metabolism of Conjugated Linoleic Acids  

Science Conference Proceedings (OSTI)

Advances in Conjugated Linoleic Acid Research, Vol 2 Chapter 15 Metabolism of Conjugated Linoleic Acids Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry 305CB38A5497B8636973A9A3E5756142 AOCS Press ...

380

Advances in Conjugated Linoleic Acid Research, Vol 2Chapter 18 Conjugated Linoleic Acid in Experimental Atherosclerosis  

Science Conference Proceedings (OSTI)

Advances in Conjugated Linoleic Acid Research, Vol 2 Chapter 18 Conjugated Linoleic Acid in Experimental Atherosclerosis Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry AA212B9659CFD264953B73B80A39B367 AOCS

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Advances in Conjugated Linoleic Acid Research, Vol 2Chapter 8 Conjugated Linoleic Acid in Food  

Science Conference Proceedings (OSTI)

Advances in Conjugated Linoleic Acid Research, Vol 2 Chapter 8 Conjugated Linoleic Acid in Food Health Nutrition Biochemistry eChapters Health - Nutrition - Biochemistry Downloadable pdf of Chapter 8 Conjugated Lino

382

Fatty Acids in Health Promotion and Disease CausationChapter 16 Ruminal Metabolism of Fatty Acids: Modulation of Polyunsaturated, Conjugated, and trans Fatty Acids in Meat and Milk  

Science Conference Proceedings (OSTI)

Fatty Acids in Health Promotion and Disease Causation Chapter 16 Ruminal Metabolism of Fatty Acids: Modulation of Polyunsaturated, Conjugated, and trans Fatty Acids in Meat and Milk Health Nutrition Biochemistry eChapters Health - Nutrit

383

Geochemistry of Hydrofluoric Acid in Kaolinitic Soils  

Science Conference Proceedings (OSTI)

This document explores the geochemical reactions likely to occur when hydrofluoric acid is spilled on Savannah River Site (SRS) soil. In particular, we evaluate the potential of environmental damage from a one-time release of concentrated hydrofluoric acid into a trench. According to interviews with personnel involved, sometime between 1955 and 1960 drums of 50-60 per cent hydrofluoric acid were disposed in a trench in the Central Shops area. The method of disposal suggests that most of the acid would have been released at the time of burial. No evidence of drum disposal or acidic pH values was found. Therefore, the Soil and Groundwater Closure Projects group requested that we evaluate potential risk by examining the major geochemical interactions expected between hydrofluoric acid and soil. The geochemical calculations in this report were done with The Geochemist's Workbench (Registered). This program uses an extended Debye-Huckel method for calculating activity coefficients. The conclusions of this report are accurate, but some of the intermediate steps may have higher uncertainty. Hydrofluoric acid disposed in a trench in the area would have reacted with soil kaolinite to neutralize the pH to a value of about 4.2. Based on conservative assumptions, this would have occurred within the top 500 cm of soil. This analysis considers only the reaction of the acid with kaolinite. Other processes such as dilution, dispersion, and clogging of permeability would contribute to neutralization of the acid within a shorter distance. When the acid solution reached the water table, dilution would have driven the solution to saturation with gibbsite. A resulting layer enriched in aluminum may be the only remnant of the acid disposal identifiable today. However, any such layer would be difficult to identify because of the normally high aluminum concentrations in the soil. Subtle textural evidence of shallow soil dissolution may be present, but 40 years of rainfall infiltration may well have erased such evidence.

DENHAM, MILES

2004-05-11T23:59:59.000Z

384

Electrostatic precipitation of condensed acid mist  

Science Conference Proceedings (OSTI)

This project addresses the acid mist that is formed by condensation of sulfuric acid vapor in flue gas from coal-fired utility boilers. An acid mist can be formed whenever the flue gas temperature approaches the prevailing acid dew point. This commonly occurs when the gas is subjected to rapid adiabatic cooling in a wet scrubber system for flue gas desulfurization. Acid mists can also sometimes result from unexpected temperature excursions caused by air inleakage, load cycling, and start-up operations. A wet electrostatic precipitator (WESP) is the best control option for acid mist. The mist would blind a fabric filter and attack glass fiber fabrics. A wet ESP is required because the acid would quickly corrode the plates in a conventional dry ESP. The wet ESP also offers the advantages of no rapping reentrainment and no sensitivity to fly ash resistivity. Therefore, this program has been structured around the use of a compact, wet ESP to control acid mist emissions. 7 refs.

Not Available

1990-01-01T23:59:59.000Z

385

Hydriodic acid-anode-depolarized hydrogen generator  

SciTech Connect

Hydrogen is recovered from aqueous hydriodic acid in the presence of sulfuric acid, in an electrolysis cell having an anode and cathode compartment separated by a hydrogen ion permeable membrane, by electrochemically liberating iodine in the anode compartment by anodization of iodide anions, and electrochemically generating hydrogen in the cathode compartment from hydrogen cations that migrate across the membrane.

Maskalick, N.J.

1984-07-17T23:59:59.000Z

386

Interaction of Nocturnal Low-Level Jets with Urban Geometries as seen in Joint URBAN 2003 Data  

DOE Green Energy (OSTI)

The nocturnal low-level jet (LLJ) is a well-documented phenomenon world-wide, especially in the southern Great Plains of the United States (Bonner 1968, Whiteman et al. 1997, Banta et al., 2002) where it contributes to severe weather. In the canonical rural case, the nocturnal LLJ forms as the release of daytime convective turbulent stresses allow nighttime winds above a stable boundary layer to accelerate to supergeostrophic wind speeds. In situations with surface winds of less than 5 m/s, wind speeds at altitudes of 100m due to the nocturnal LLJ can be greater than 20 m/s. The turbulence generated by this wind shear can induce nocturnal mixing events and control surface-atmosphere exchange, thereby affecting atmospheric transport and dispersion. The Joint URBAN 2003 urban dispersion dataset, collected in Oklahoma City in July, 2003, includes several occurrences of strong LLJs, thereby providing a unique opportunity to document how the LLJ interacts with the complexity of urban geometries and to explore the significance of LLJs for transport and dispersion in urban environments. Based on this dataset, we will answer the following questions: (1) How often do LLJs occur during the experiment? (2) How does the increase in surface roughness represented by the city center, as compared to the rural environment, affect the altitude and speed of the jet, based on data from upwind and downwind wind profiles? (3) How often do LLJs contribute to nocturnal mixing events within the Oklahoma City urban area, as observed in profiles of turbulence quantities at an 80m pseudo-tower located 750m downwind of Oklahoma City center? (4) Can the effect of these LLJ-induced mixing events be identified in the dispersion datasets?

Lundquist, J K

2005-07-13T23:59:59.000Z

387

Multiphysics Simulations of the Complex 3D Geometry of the High Flux Isotope Reactor Fuel Elements Using COMSOL  

Science Conference Proceedings (OSTI)

A research and development project is ongoing to convert the currently operating High Flux Isotope Reactor (HFIR) of Oak Ridge National Laboratory (ORNL) from highly-enriched Uranium (HEU U3O8) fuel to low-enriched Uranium (LEU U-10Mo) fuel. Because LEU HFIR-specific testing and experiments will be limited, COMSOL is chosen to provide the needed multiphysics simulation capability to validate against the HEU design data and calculations, and predict the performance of the LEU fuel for design and safety analyses. The focus of this paper is on the unique issues associated with COMSOL modeling of the 3D geometry, meshing, and solution of the HFIR fuel plate and assembled fuel elements. Two parallel paths of 3D model development are underway. The first path follows the traditional route through examination of all flow and heat transfer details using the Low-Reynolds number k-e turbulence model provided by COMSOL v4.2. The second path simplifies the fluid channel modeling by taking advantage of the wealth of knowledge provided by decades of design and safety analyses, data from experiments and tests, and HFIR operation. By simplifying the fluid channel, a significant level of complexity and computer resource requirements are reduced, while also expanding the level and type of analysis that can be performed with COMSOL. Comparison and confirmation of validity of the first (detailed) and second (simplified) 3D modeling paths with each other, and with available data, will enable an expanded level of analysis. The detailed model will be used to analyze hot-spots and other micro fuel behavior events. The simplified model will be used to analyze events such as routine heat-up and expansion of the entire fuel element, and flow blockage. Preliminary, coarse-mesh model results of the detailed individual fuel plate are presented. Examples of the solution for an entire fuel element consisting of multiple individual fuel plates produced by the simplified model are also presented.

Freels, James D [ORNL; Jain, Prashant K [ORNL

2011-01-01T23:59:59.000Z

388

Proceedings of the 17 th GAMM-Seminar Leipzig 2001, pp. 29{54 Description and generation of geometries and grids  

E-Print Network (OSTI)

10000 15000 20000 25000 30000 35000 "WIPP_2D.lgm" 6 surfcaes, 3 outcrops 3 triangles, 57 quadrilaterals WIPP2D.ng WIPP2D.lgm Figure 22: lgm2ng: WIPP domain 2D, lgm-geometry and ng-mesh Fig. 22 shows the WIPP by lgm2ng. In reality the horizontal extension of the WIPP-domain is 35 kilometers whereas the thickness

389

Effect of Conjugated Linoleic Acid or Oleic Acid Addition on Fatty Acid Composition Profiles of Poultry Meat  

E-Print Network (OSTI)

Two different studies were conducted to reduce the overall amount of omega-6 fatty acids in broiler chickens. The first experiment was performed to determine the effects of dietary conjugated linoleic acid (CLA) and omega-3 fatty acid combination on the omega-6 fatty acid accumulation in broiler chicken breast and thigh meat. Eight broilers from each treatment were processed at 4 and 6 weeks of age, respectively. Regarding the diets containing five different fat sources, broiler chickens fed CLA and fish oil diet had a lower C20:4 (arachidonic acid, AA, n-6) deposition but showed a higher n-3/n-6 ratio in breast and thigh meat than those fed a flaxseed oil diet and CLA and flaxseed oil diet (P 0.05). However, the addition of CLA and fish oil to the diet resulted in a increase of polyunsaturated fatty acid (PUFA) concentration in broiler chicken breast and thigh meat when compared to that of fish oil diet (P<0.05). The second experiment was conducted based on six different combination of n-3 and n-9 fatty acids. One bird per pen was processed, and each bird was weighed, and blood, liver, breast and thigh samples from the bird were collected. Although the generation of prostaglandin E2 (PGE2) was not affected due to combination of n-3 and n-9 fatty acids in our diets, the deposition of n-6 fatty acids including C18:2 and C20:4 was decreased in broiler chicken breast and/or thigh muscles as n-3 fatty acids were supplied to broiler chickens for 9 weeks. Eicosapentaenoic acid (C20:5, EPA, n-3) addition to poultry diet (FEO) did not reduce the deposition of C18:2 and/or C20:4 as much as C22:6 (FDO) did. When C20:5 and C22:6 were blended to poultry diet (FHO) and fed to broiler chickens for 9 weeks, synergistic effects were observed. Reduction of C20:4 was obtained when FHO diet was fed to broiler chickens, and it may be induced due to decreased expression of delta-6 desaturase mRNA.

Shin, Dae Keun

2010-05-01T23:59:59.000Z

390

Advances in Conjugated Linoleic Acid Research, Vol 2  

Science Conference Proceedings (OSTI)

Advances in Conjugated Linoleic Acid Research, Volume 2, is the second book in a series devoted entirely to conjugated linoleic acid. Advances in Conjugated Linoleic Acid Research, Vol 2 Health Nutrition Biochemistry Hardback Books Health - Nutrition

391

Fatty Acids in Health Promotion and Disease Causation  

Science Conference Proceedings (OSTI)

The Fatty Acids in Health Promotion and Disease Causation book has four main focuses and sections. Fatty Acids in Health Promotion and Disease Causation Health acid analysis aocs april articles chloropropanediol contaminants detergents dietary fats divis

392

PREDICTING TEMPERATURE BEHAVIOR IN CARBONATE ACIDIZING TREATMENTS  

E-Print Network (OSTI)

To increase the successful rate of acid stimulation, a method is required to diagnose the effectiveness of stimulation which will help us to improve stimulation design and decide whether future action, such as diversion, is needed. For this purpose, it is important to know how much acid enters each layer in a multilayer carbonate formation and if the low-permeability layer is treated well. This work develops a numerical model to determine the temperature behavior for both injection and flow-back situations. An important phenomenon in this process is the heat generated by reaction, affecting the temperature behavior significantly. The result of the thermal model showed significant temperature effects caused by reaction, providing a mechanism to quantitatively determine the acid flow profile. Based on this mechanism, a further inverse model can be developed to determine the acid distribution in each layer.

Tan, Xuehao

2009-05-01T23:59:59.000Z

393

Replica amplification of nucleic acid arrays  

DOE Patents (OSTI)

Disclosed are improved methods of making and using immobilized arrays of nucleic acids, particularly methods for producing replicas of such arrays. Included are methods for producing high density arrays of nucleic acids and replicas of such arrays, as well as methods for preserving the resolution of arrays through rounds of replication. Also included are methods which take advantage of the availability of replicas of arrays for increased sensitivity in detection of sequences on arrays. Improved methods of sequencing nucleic acids immobilized on arrays utilizing single copies of arrays and methods taking further advantage of the availability of replicas of arrays are disclosed. The improvements lead to higher fidelity and longer read lengths of sequences immobilized on arrays. Methods are also disclosed which improve the efficiency of multiplex PCR using arrays of immobilized nucleic acids.

Church, George M. (Brookline, MA); Mitra, Robi D. (Chestnut Hill, MA)

2010-08-31T23:59:59.000Z

394

NH Acid Rain Control Act (New Hampshire)  

Energy.gov (U.S. Department of Energy (DOE))

The Act is implemented under New Hampshire's acid deposition control program established under the Rules to Control Air Pollution in Chapter Env-A 400. The goal of the Act is to reduce emissions...

395

The Hunter Region (Australia) Acid Rain Project  

Science Conference Proceedings (OSTI)

Field measurements for the Hunter Region Acid Rain Project were conducted as a major co-operative effort by the New South Wales State Pollution Control Commission, the Electricity Commission of New South Wales, and the University of Newcastle in ...

Howard A. Bridgman; Robert Rothwell; Christopher Pang Way; Peng-Hing Tio

1988-03-01T23:59:59.000Z

396

Phosphonic acid based ion exchange resins  

DOE Patents (OSTI)

An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 9 figures.

Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

1994-01-25T23:59:59.000Z

397

The Spatial Analysis of Acid Precipitation Data  

Science Conference Proceedings (OSTI)

Kriging, an interpolation procedure that minimizes interpolation error and gives an accurate estimate of that error, is shown to be an appropriate objective analysis procedure for the study of spatial variability and structure in acid ...

Peter L. Finkelstein

1984-01-01T23:59:59.000Z

398

A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid  

E-Print Network (OSTI)

R.G.B and J.A.E. ). Keywords: biomass carboxylic acids 10.1002/cssc.201000111 A Direct, Biomass-Based Synthesis ofaro- matic compounds from biomass resources could provide a

2010-01-01T23:59:59.000Z

399

Optimizing amino acid groupings for GPCR classification  

Science Conference Proceedings (OSTI)

Motivation: There is much interest in reducing the complexity inherent in the representation of the 20 standard amino acids within bioinformatics algorithms by developing a so-called reduced alphabet. Although there is no universally applicable ...

Matthew N. Davies; Andrew Secker; Alex A. Freitas; Edward Clark; Jon Timmis; Darren R. Flower

2008-09-01T23:59:59.000Z

400

Dynamic Protonation Equilibrium of Solvated Acetic Acid  

Science Conference Proceedings (OSTI)

For the first time, the dynamic protonation equilibrium between an amino acid side chain analogue and bulk water as well as the diffusion properties of the excess proton were successfully reproduced through unbiased computer simulations. During a 50 ns Q-HOP MD simulation, two different regimes of proton transfer were observed. Extended phases of frequent proton swapping between acetic acid and nearby water were separated by phases where the proton freely diffuses in the simulation box until it is captured again by acetic acid. The pKa of acetic acid was calculated around 3.0 based on the relative population of protonated and deprotonated states and the diffusion coefficient of excess proton was computed from the average mean squared displacement in the simulation. Both calculated values agree well with the experimental measurements.

Gu, Wei; Frigato, Tomaso; Straatsma, TP; Helms, Volkhard H.

2007-04-13T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Thermodynamic Properties of Acetic Acid + Hydrocarbons ...  

Science Conference Proceedings (OSTI)

Thermodynamic Properties of Acetic Acid + Hydrocarbons Mixtures L. Negadi1,C,S, N. Ainous2, A. Negadi1, I. Mokbel2, A. Kaci3 and J. Jose2 ...

2006-07-20T23:59:59.000Z

402

A macromolecular delivery vehicle for protein-based vaccines: Acid ...  

... methane, was designed as the key acid-cleavable crosslinking monomer used to prepare acid-degradable protein-loaded microgels by inverse ...

403

Preferential Acidic, Alkaline and Neutral Solubility of Metallic...  

NLE Websites -- All DOE Office Websites (Extended Search)

water is a neutral liquid, representative of exposure to surface water or groundwater. Acetic acid is a weak organic acid, and is an indicator of potential leaching during...

404

(2-ethylhexyl)-mono (2-ethylhexyl) ester Phosphonic acid  

Science Conference Proceedings (OSTI)

Comparison among different extractants, as (2-ethylhexyl)-mono (2-ethylhexyl) ester Phosphonic acid (P507), Secondary-octyl phenoxy acetic acid (CA-12) and ...

405

Synthesis of a New Asymmetric Dialkylphophinic Acid and Its ...  

Science Conference Proceedings (OSTI)

Besides, as to symmetrical dialkylphosphinic acids when the branched chain ... Di-(2,4,4'-trimethylpentyl)-phosphinic acid (main component of Cyanex 272).

406

Biologically produced acid precipitable polymeric lignin  

DOE Patents (OSTI)

A water soluble, acid precipitable polymeric degraded lignin (APPL), having a molecular weight of at least 12,000 daltons, and comprising, by percentage of total weight, at least three times the number of phenolic hydroxyl groups and carboxylic acid groups present in native lignin. The APPL may be modified by chemical oxidation and reduction to increase its phenolic hydroxyl content and reduce the number of its antioxidant inhibitory side chains, thereby improving antioxidant properties.

Crawford, Don L. (Moscow, ID); Pometto, III, Anthony L. (Moscow, ID)

1984-01-01T23:59:59.000Z

407

Primer on lead-acid storage batteries  

DOE Green Energy (OSTI)

This handbook was developed to help DOE facility contractors prevent accidents caused during operation and maintenance of lead-acid storage batteries. Major types of lead-acid storage batteries are discussed as well as their operation, application, selection, maintenance, and disposal (storage, transportation, as well). Safety hazards and precautions are discussed in the section on battery maintenance. References to industry standards are included for selection, maintenance, and disposal.

NONE

1995-09-01T23:59:59.000Z

408

Nitric acid requirement for treating sludge  

DOE Green Energy (OSTI)

The hydroxylamine nitrate (HAN) precipitate hydrolysis process produces sufficient oxidant (nitrate) such that the resulting blend of formic acid treated sludge and the aqueous product from hydrolysis (PHA) produces a melter feed of acceptable redox (i.e. Fe+2/Total Fe <0.33). With implementation of Late Washing (to reduce the nitrite content of the tetraphenyborate slurry produced during In-Tank Precipitation to 0.01M or less), HAN is no longer required during hydrolysis. As a result, the nitrate content of the melter feed will be reduced greater than an order-of-magnitude and the resulting melter feed produced will be too reducing. If formic acid treatment of the sludge is retained, it will be necessary to trim the melter feed with an oxidant to attain a proper redox. Rather than trimming the melter feed with an oxidant subsequent to the SRAT cycle in which formic acid is used to acidify the sludge, the Savannah River Technology Center (SRTC) has recommended this be accomplished by conversion to nitric acid addition to the Sludge Receipt and Adjustment Tank (SRAT) in place of formic acid (1). This memorandum specifies the stoichiometric bases for determining the nitric acid requirement for the SRAT.

Hsu, C.W.

1992-09-04T23:59:59.000Z

409

Effects of Acid Additives on Spent Acid Flowback through Carbonate Cores  

E-Print Network (OSTI)

Matrix acidizing is a well stimulation technique used to remove formation damage in the near wellbore region. But it comes with an associated set of challenges such as corrosion of the tubulars and iron precipitation in the formation. To counter these challenges, different chemicals, or additives, are added to the acid solution such as corrosion inhibitors and iron control agents. These additives may change the relative permeability of the spent acid, and formation wettability, and may either hinder or improve spent acid clean-up. Such effects of additives on the spent acid clean-up have not been documented. The aim of this research effort was to document the aforementioned change in the spent acid concentration (by using one additive at a time) before and after gas flowback. This was achieved by acidizing cores and creating wormholes halfway through them, then CT scanning them to observe the spent acid region. Later on, gas was flown through the core opposite to the direction of acid injection for 2 hours, and another CT scan was taken. The difference between the two CT scans was documented. Using a different additive each time, a series of such CT scans was obtained to develop an idea about whether the said additive was beneficial or detrimental to spent acid clean-up. It was found that the corrosion inhibitor FA-CI performed the best in terms of spent acid recovery after gas flowback for both Indiana Limestone and Texas Cream Chalk cores. Moreover, the corrosion inhibitor MI-CI was the worst for Indiana Limestone and the non-emulsifying agent M-NEA the worst for Texas Cream Chalk for spent acid recovery after gas flowback.

Nasir, Ehsaan Ahmad

2012-05-01T23:59:59.000Z

410

Acid Diversion in Carbonate Reservoirs Using Polymer-Based In-Situ Gelled Acids  

E-Print Network (OSTI)

Diversion in carbonates is more difficult than in sandstones because of the ability of acid to significantly increase the permeability in carbonates as it reacts in the pore spaces and flow channels of matrix. In-situ gelled acids that are based on polymers have been used in the field for several years and were the subject of many lab studies. An extensive literature survey reveals that there are conflicting opinions about using these acids. On one hand, these acids were used in the field with mixed results. Recent lab work indicated that these acids can cause damage under certain conditions. There is no agreement on when this system can be successfully applied in the field. Therefore, this study was conducted to better understand this acid system and determine factors that impact its performance. Lab test of polymer-based in-situ gelled acids reveal that polymer and other additives separate out of the acid when these acids are prepared in high salinity water. In coreflood tests, in-situ gelled acid formed a gel inside 20 long core samples, and the acid changed its direction several times. Unexpectantly, the core's permeability was reduced at low shear rate. Wormhole length increased as the shear rate was increased; while the diameter of the wormhole increased as the acid cumulative injected volume was increased. CT scan indicated the presence of gel residue inside and around the wormhole. Gel residue increased at low shear rates. Material balance on the cross-linker indicated that a significant amount of the crosslinker was retained in the core. Based on the results obtained from this study the in-situ gelled acids should be used only at low HCl concentrations (5 wt percent HCl). Acid should be prepared in low salinity water and the acid injection rate should be determined based on the expected shear rate in the formation. A core flood experiment is recommended to confirm optimum injected rate. Well flow back is needed to minimize the residual gel inside the formation. The data obtained in this study can be used as a guideline for injection rate selection.

Gomaa, Ahmed Mohamed Mohamed

2011-05-01T23:59:59.000Z

411

Energy densification of biomass-derived organic acids  

DOE Patents (OSTI)

A process for upgrading an organic acid includes neutralizing the organic acid to form a salt and thermally decomposing the resulting salt to form an energy densified product. In certain embodiments, the organic acid is levulinic acid. The process may further include upgrading the energy densified product by conversion to alcohol and subsequent dehydration.

Wheeler, M. Clayton

2013-01-29T23:59:59.000Z

412

Sulfuric acid-sulfur heat storage cycle  

DOE Patents (OSTI)

A method of storing heat is provided utilizing a chemical cycle which interconverts sulfuric acid and sulfur. The method can be used to levelize the energy obtained from intermittent heat sources, such as solar collectors. Dilute sulfuric acid is concentrated by evaporation of water, and the concentrated sulfuric acid is boiled and decomposed using intense heat from the heat source, forming sulfur dioxide and oxygen. The sulfur dioxide is reacted with water in a disproportionation reaction yielding dilute sulfuric acid, which is recycled, and elemental sulfur. The sulfur has substantial potential chemical energy and represents the storage of a significant portion of the energy obtained from the heat source. The sulfur is burned whenever required to release the stored energy. A particularly advantageous use of the heat storage method is in conjunction with a solar-powered facility which uses the Bunsen reaction in a water-splitting process. The energy storage method is used to levelize the availability of solar energy while some of the sulfur dioxide produced in the heat storage reactions is converted to sulfuric acid in the Bunsen reaction.

Norman, John H. (LaJolla, CA)

1983-12-20T23:59:59.000Z

413

Application of a multi-block CFD code to investigate the impact of geometry modeling on centrifugal compressor flow field predictions  

Science Conference Proceedings (OSTI)

CFD codes capable of utilizing multi-block grids provide the capability to analyze the complete geometry of centrifugal compressors. Attendant with this increased capability is potentially increased grid setup time and more computational overhead with the resultant increase in wall clock time to obtain a solution. If the increase in difficulty of obtaining a solution significantly improves the solution from that obtained by modeling the features of the tip clearance flow or the typical bluntness of a centrifugal compressor`s trailing edge, then the additional burden is worthwhile. However, if the additional information obtained is of marginal use, then modeling of certain features of the geometry may provide reasonable solutions for designers to make comparative choices when pursuing a new design. In this spirit a sequence of grids were generated to study the relative importance of modeling versus detailed gridding of the tip gap and blunt trailing edge regions of the NASA large low-speed centrifugal compressor for which there is considerable detailed internal laser anemometry data available for comparison. The results indicate: (1) There is no significant difference in predicted tip clearance mass flow rate whether the tip gap is gridded or modeled. (2) Gridding rather than modeling the trailing edge results in better predictions of some flow details downstream of the impeller, but otherwise appears to offer no great benefits. (3) The pitchwise variation of absolute flow angle decreases rapidly up to 8% impeller radius ratio and much more slowly thereafter. Although some improvements in prediction of flow field details are realized as a result of analyzing the actual geometry there is no clear consensus that any of the grids investigated produced superior results in every case when compared to the measurements. However, if a multi-block code is available, it should be used, as it has the propensity for enabling better predictions than a single block code.

Hathaway, M.D. [Vehicle Technology Center, Cleveland, OH (United States); Wood, J.R. [NASA Lewis Research Center, Cleveland, OH (United States)

1997-10-01T23:59:59.000Z

414

Neutronics and Depletion Methods for Parametric Studies of Fluoride Salt Cooled High Temperature Reactors with Slab Fuel Geometry and Multi-Batch Fuel Management Schemes  

SciTech Connect

The Advanced High Temperature Reactor (AHTR) is a 3400 MWth fluoride salt cooled high temperature reactor (FHR) that uses TRISO particle fuel compacted into slabs rather than spherical fuel pebbles or cylindrical fuel compacts. Simplified methods are required for parametric design studies such that analyzing the entire feasible design space for an AHTR is tractable. These simplifications include fuel homogenization techniques to increase the speed of neutron transport calculations in depletion analysis and equilibrium depletion analysis methods to analyze systems with multi-batch fuel management schemes. This paper presents three elements of significant novelty. First, the reactivity-equivalent physical transformation (RPT) methodology usually applied in systems with coated particle fuel in cylindrical and spherical geometries was extended to slab geometries. Secondly, based on this newly developed RPT method for slab geometries, a methodology that uses Monte Carlo depletion approaches was further developed to search for the maximum discharge burnup in a multi-batch system by iteratively estimating the beginning of equilibrium cycle composition and sampling different discharge burnups. This iterative equilibrium depletion search (IEDS) method fully defines an equilibrium fuel cycle (keff, power, flux and composition evolutions across space and time), but is computationally demanding, although feasible on single-processor workstations. Finally, an analytical method, the non-linear reactivity model, was developed by expanding the linear reactivity model to include an arbitrary number of higher order terms to extrapolate single-batch depletion results to estimate the maximum discharge burnup and BOEC keff in systems with multi-batch fuel management schemes. Results from this method were benchmarked against equilibrium depletion analysis results using the IEDS.

Cisneros, Anselmo T. [University of California, Berkeley; Ilas, Dan [ORNL

2012-01-01T23:59:59.000Z

415

Neutronics and Depletion Methods for Parametric Studies of Fluoride Salt Cooled High Temperature Reactors with Slab Fuel Geometry and Multi-Batch Fuel Management Schemes  

SciTech Connect

The Advanced High-Temperature Reactor (AHTR) is a 3400 MWth fluoride-salt-cooled high-temperature reactor (FHR) that uses TRISO particle fuel compacted into slabs rather than spherical or cylindrical fuel compacts. Simplified methods are required for parametric design studies such that analyzing the entire feasible design space for an AHTR is tractable. These simplifications include fuel homogenization techniques to increase the speed of neutron transport calculations in depletion analysis and equilibrium depletion analysis methods to analyze systems with multi-batch fuel management schemes. This paper presents three elements of significant novelty. First, the Reactivity-Equivalent Physical Transformation (RPT) methodology usually applied in systems with coated-particle fuel in cylindrical and spherical geometries has been extended to slab geometries. Secondly, based on this newly developed RPT method for slab geometries, a methodology that uses Monte Carlo depletion approaches was further developed to search for the maximum discharge burnup in a multi-batch system by iteratively estimating the beginning of equilibrium cycle (BOEC) composition and sampling different discharge burnups. This Iterative Equilibrium Depletion Search (IEDS) method fully defines an equilibrium fuel cycle (keff, power, flux, and composition evolutions) but is computationally demanding, although feasible on single-processor workstations. Finally, an analytical method, the Non-Linear Reactivity Model, was developed by expanding the linear reactivity model to include an arbitrary number of higher order terms so that single-batch depletion results could be extrapolated to estimate the maximum discharge burnup and BOEC keff in systems with multi-batch fuel management schemes. Results from this method were benchmarked against equilibrium depletion analysis results using the IEDS.

Cisneros, Anselmo T. [University of California, Berkeley; Ilas, Dan [ORNL

2013-01-01T23:59:59.000Z

416

ITS version 5.0 :the integrated TIGER series of coupled electron/Photon monte carlo transport codes with CAD geometry.  

Science Conference Proceedings (OSTI)

ITS is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of linear time-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Our goal has been to simultaneously maximize operational simplicity and physical accuracy. Through a set of preprocessor directives, the user selects one of the many ITS codes. The ease with which the makefile system is applied combines with an input scheme based on order-independent descriptive keywords that makes maximum use of defaults and internal error checking to provide experimentalists and theorists alike with a method for the routine but rigorous solution of sophisticated radiation transport problems. Physical rigor is provided by employing accurate cross sections, sampling distributions, and physical models for describing the production and transport of the electron/photon cascade from 1.0 GeV down to 1.0 keV. The availability of source code permits the more sophisticated user to tailor the codes to specific applications and to extend the capabilities of the codes to more complex applications. Version 5.0, the latest version of ITS, contains (1) improvements to the ITS 3.0 continuous-energy codes, (2) multigroup codes with adjoint transport capabilities, (3) parallel implementations of all ITS codes, (4) a general purpose geometry engine for linking with CAD or other geometry formats, and (5) the Cholla facet geometry library. Moreover, the general user friendliness of the software has been enhanced through increased internal error checking and improved code portability.

Franke, Brian Claude; Kensek, Ronald Patrick; Laub, Thomas William

2005-09-01T23:59:59.000Z

417

Pakistan Vet. J., 24(3): 2004 EFFECTS OF ASCORBIC ACID AND ACETYLSALICYLIC ACID  

E-Print Network (OSTI)

Pakistan Vet. J., 24(3): 2004 109 EFFECTS OF ASCORBIC ACID AND ACETYLSALICYLIC ACID SUPPLEMENTATION Sciences, Lahore-54000, Pakistan ABSTRACT A total of 100, day-old broiler chicks were randomly divided production in the tropics. In Pakistan, temperature remains well beyond the higher side of thermoneutral zone

Paris-Sud XI, Université de

418

System for agitating the acid in a lead-acid battery  

DOE Patents (OSTI)

A system and method for agitating the acid in a large lead-sulfuric acid storage battery of the calcium type. An air-lift is utilized to provide the agitation. The air fed to the air-lift is humidified prior to being delivered to the air-lift.

Weintraub, Alvin (Schenectady, NY); MacCormack, Robert S. (Glenville, NY)

1987-01-01T23:59:59.000Z

419

Purification Or Organic Acids Using Anion Exchange Chromatography.  

DOE Patents (OSTI)

Disclosed is a cost-effective method for purifying and acidifying carboxylic acids, including organic acids and amino acids. The method involves removing impurities by allowing the anionic form of the carboxylic acid to bind to an anion exchange column and washing the column. The carboxylic anion is displaced as carboxylic acid by washing the resin with a strong inorganic anion. This method is effective in removing organic carboxylic acids and amino acids from a variety of industrial sources, including fermentation broths, hydrolysates, and waste streams.

Ponnampalam; Elankovan (Okemos, MI)

2001-09-04T23:59:59.000Z

420

Reduction of Pertechnetate By Acetohydroxamic Acid: Formation of [tc**II(NO)(AHA)(2)(H(2)O)]**+ And Implications for the UREX Process  

Science Conference Proceedings (OSTI)

Reductive nitrosylation and complexation of ammonium pertechnetate by acetohydroxamic acid has been achieved in aqueous nitric and perchloric acid solutions. The kinetics of the reaction depend on the relative concentrations of the reaction components and are accelerated at higher temperatures. The reaction does not occur unless conditions are acidic. Analysis of the X-ray absorption fine structure spectroscopic data is consistent with a pseudo-octahedral geometry and the linear Tc-N-O bond typical of technetium nitrosyl compounds, and electron spin resonance spectroscopy is consistent with a d{sup 5} Tc(II) nitrosyl complex. The nitrosyl source is generally AHA, but it may be augmented by some products of the reaction with nitric acid. The resulting low-valency trans-aquonitrosyl(diacetohydroxamic)-technetium(II) complex ([Tc{sup II}(NO)(AHA){sub 2}H{sub 2}O]{sup +}, 1) is highly soluble in water, extremely hydrophilic, and is not extracted by tri-n-butylphosphate in a dodecane diluent. Its extraction properties are not pH-dependent: potentiometric-spectrophotometric titration studies indicate a single species from pH 4 down to -0.6 (calculated). This molecule is resistant to oxidation by H{sub 2}O{sub 2}, even at high pH, and can undergo substitution to form other technetium nitrosyl complexes. The potential formation of 1 during reprocessing may strongly impact the fate of technetium in the nuclear fuel cycle.

Gong, C.-M.S.; Lukens, W.W.; Poineau, F.; Czerwinski, K.R.

2009-05-18T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Reduction of pertechnetate by acetohydroxamic acid: Formation of [TcNO(AHA)2(H2O)]+ and implications for the UREX process.  

Science Conference Proceedings (OSTI)

Reductive nitrosylation and complexation of ammonium pertechnetate by acetohydroxamic acid has been achieved in aqueous nitric and perchloric acid solutions. The kinetics of the reaction depend on the relative concentrations of the reaction components and are accelerated at higher temperatures. The reaction does not occur unless conditions are acidic. Analysis of the x-ray absorption fine structure spectroscopic data is consistent with a pseudo-octahedral geometry with the linear Tc-N-O bond typical of technetium nitrosyl compounds, and electron spin resonance spectroscopy is consistent with a the d{sup 5} Tc(II) nitrosyl complex. The nitrosyl source is generally AHA, but may be augmented by products of reaction with nitric acid. The resulting low-valency trans-aquonitrosyl(diacetohydroxamic)-technetium(II) complex (1) is highly soluble in water, extremely hydrophilic, and is not extracted by tri-n-butylphosphate in a dodecane diluent. Its extraction properties are not pH-dependent; titration studies indicate a single species from pH 4.5 down to -0.6 (calculated). This molecule is resistant to oxidation by H{sub 2}O{sub 2}, even at high pH, and can undergo substitution to form other technetium nitrosyl complexes. The formation of 1 may strongly impact the fate of technetium in the nuclear fuel cycle.

1Harry Reid Center for Environmental Studies, Nuclear Science and Technology Division, University of Nevada, Las Vegas, Las Vegas, NV, 89154-4006; Gong, Cynthia-May S; Poineau, Frederic; Lukens, Wayne W; Czerwinski, Kenneth R.

2008-02-26T23:59:59.000Z

422

Electrostatic precipitation of condensed acid mist  

Science Conference Proceedings (OSTI)

The purpose of this project is to develop and demonstrate a compact, wet electrostatic collector for condensed acid mist in power plant flue gas. The following are project objectives: (1) fabrication of laboratory-version of the WESP; (2) optimization of the WESP performance through laboratory tests with a non-volatile simulant aerosol having a size distribution similar to the acid mist; (3) demonstration of adequate collection of actual acid mist in a pilot coal combustion facility under conditions simulating full-scale power plant burning high-sulfur coal; (4) development of computer model of the WESP process must be developed to assist in the process optimization, interpretation of test results, and extrapolation to full scale; and (5) solicitation of utility participation in a follow-on demonstration of the WESP concept at a full-scale power plant. The WESP fabrication, laboratory and pilot combustor testing, and computer modeling is discussed. 5 refs., 5 figs.

Not Available

1989-01-01T23:59:59.000Z

423

Photoenhanced anaerobic digestion of organic acids  

DOE Patents (OSTI)

A process is described for rapid conversion of organic acids and alcohols in anaerobic digesters into hydrogen and carbon dioxide, the optimal precursor substrates for production of methane. The process includes addition of photosynthetic bacteria to the digester and exposure of the bacteria to radiant energy (e.g., solar energy). The process also increases the pH stability of the digester to prevent failure of the digester. Preferred substrates for photosynthetic bacteria are the organic acid and alcohol waste products of fermentative bacteria. In mixed culture with methanogenic bacteria or in defined co-culture with non-aceticlastic methanogenic bacteria, photosynthetic bacteria are capable of facilitating the conversion of organic acids and alcohols into methane with low levels of light energy input. 8 figs.

Weaver, P.F.

1989-08-25T23:59:59.000Z

424

Water and UV degradable lactic acid polymers  

DOE Patents (OSTI)

A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer were selected from the class consisting of ethylene and polyethylene glycols, propylene and polypropylene glycols, P-dioxanone, 1,5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide where the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures to an agricultural site is also disclosed.

Bonsignore, P.V.; Coleman, R.D.

1994-11-01T23:59:59.000Z

425

Photoenhanced anaerobic digestion of organic acids  

DOE Patents (OSTI)

A process is described for rapid conversion of organic acids and alcohols anaerobic digesters into hydrogen and carbon dioxide, the optimal precursor substrates for production of methane. The process includes addition of photosynthetic bacteria to the digester and exposure of the bacteria to radiant energy (e.g., solar energy). The process also increases the pH stability of the digester to prevent failure of the digester. Preferred substrates for photosynthetic bacteria are the organic acid and alcohol waste products of fermentative bacteria. In mixed culture with methanogenic bacteria or in defined co-culture with non-aceticlastic methanogenic bacteria, photosynthetic bacteria are capable of facilitating the conversion or organic acids and alcohols into methane with low levels of light energy input.

Weaver, Paul F. (Golden, CO)

1990-01-01T23:59:59.000Z

426

Water and UV degradable lactic acid polymers  

DOE Patents (OSTI)

A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene and polyethylane glycols (PVB 6/22/90), propylene and and polypropylene (PVB 6/22/90) glycols, P-dioxanone, 1, 5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

Bonsignore, P.V.; Coleman, R.D.

1990-06-26T23:59:59.000Z

427

IMPROVED PROCESSES TO REMOVE NAPHTHENIC ACIDS  

SciTech Connect

In the first year of this project, we have established our experimental and theoretical methodologies for studies of the catalytic decarboxylation process. We have developed both glass and stainless steel micro batch type reactors for the fast screening of various catalysts with reaction substrates of model carboxylic acid compounds and crude oil samples. We also developed novel product analysis methods such as GC analyses for organic acids and gaseous products; and TAN measurements for crude oil. Our research revealed the effectiveness of several solid catalysts such as NA-Cat-1 and NA-Cat-2 for the catalytic decarboxylation of model compounds; and NA-Cat-5{approx}NA-Cat-9 for the acid removal from crude oil. Our theoretical calculations propose a three-step concerted oxidative decarboxylation mechanism for the NA-Cat-1 catalyst.

Aihua Zhang; Qisheng Ma; William A. Goddard; Yongchun Tang

2004-04-28T23:59:59.000Z

428

Water and UV degradable lactic acid polymers  

DOE Patents (OSTI)

A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene and polyethylene glycols, propylene and polypropylene glycols, P-dioxanone, 1,5 dioxepan-2-one, 1,4 -oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2% by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

Bonsignore, Patrick V. (Joliet, IL); Coleman, Robert D. (Wheaton, IL)

1994-01-01T23:59:59.000Z

429

Water and UV degradable lactic acid polymers  

DOE Patents (OSTI)

A water and UV light degradable copolymer of monomers of lactic acid and a modifying monomer selected from the class consisting of ethylene glycol, propylene glycol, P-dioxanone, 1,5 dioxepan-2-one, 1,4-oxathialan-2-one, 1,4-dioxide and mixtures thereof. These copolymers are useful for waste disposal and agricultural purposes. Also disclosed is a water degradable blend of polylactic acid or modified polylactic acid and high molecular weight polyethylene oxide wherein the high molecular weight polyethylene oxide is present in the range of from about 2 by weight to about 50% by weight, suitable for films. A method of applying an active material selected from the class of seeds, seedlings, pesticides, herbicides, fertilizers and mixtures thereof to an agricultural site is also disclosed.

Bonsignore, Patrick V. (Joliet, IL); Coleman, Robert D. (Wheaton, IL)

1996-01-01T23:59:59.000Z

430

The Influence of Linker Geometry on Uranyl Complexation by Rigidly-Linked Bis(3-hydroxy-N-methyl-pyridin-2-one)  

DOE Green Energy (OSTI)

A series of bis(3-hydroxy-N-methyl-pyridin-2-one) ligands was synthesized, and their respective uranyl complexes were characterized by single crystal X-ray diffraction analyses. These structures were inspected for high-energy conformations and evaluated using a series of metrics to measure co-planarity of chelating moieties with each other and the uranyl coordination plane, as well as to measure coordinative crowding about the uranyl dication. Both very short (ethyl, 3,4-thiophene and o-phenylene) and very long ({alpha},{alpha}{prime}-m-xylene and 1,8-fluorene) linkers provide optimal ligand geometries about the uranyl cation, resulting in planar, unstrained molecular arrangements. The planarity of the rigid linkers also suggests there is a degree of pre-organization for a planar coordination mode that is ideal for uranyl-selective ligand design. Comparison of intramolecular N{sub amide}-O{sub phenolate} distances and {sup 1}H NMR chemical shifts of amide protons supports earlier results that short linkers provide the optimal geometry for intramolecular hydrogen bonding.

Szigethy, Geza; Raymond, Kenneth

2010-04-22T23:59:59.000Z

431

LES ACIDES GRAS TRANS DU BEURRE II.  

E-Print Network (OSTI)

origine est essentiellement endogène car les aliments naturels habituellement distribués aux vaches) au cours de l'hydro- génation biologique portant sur les acides oléique, linoléique et linolénique

Recanati, Catherine

432

Separators for valve regulated lead acid batteries  

Science Conference Proceedings (OSTI)

This paper reviews some aspects of the past history of the valve regulated lead acid (VRLA) battery in relationship to microglass separators that have been used from the conception of VRLA technology. It also focuses on some aspects of compression properties of the separator.

Zguris, G.C. [Hollingsworth & Vose Co., West Groton, MT (United States)

1995-01-01T23:59:59.000Z

433

Method for the production of dicarboxylic acids  

DOE Patents (OSTI)

The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of (a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; (b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; (c) controllably releasing oxygen to maintain the aerobic atmosphere; (d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/l up to about 1 g/l; (e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; (f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of {>=}1 g/l; and (g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism. 7 figs.

Nghiem, N.P.; Donnelly, M.; Millard, C.S.; Stols, L.

1999-02-09T23:59:59.000Z

434

Method for the production of dicarboxylic acids  

DOE Patents (OSTI)

The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; c) controllably releasing oxygen to maintain the aerobic atmosphere; d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/L up to about 1 g/L; e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of .gtoreq.1 g/L; and g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism.

Nghiem, Nhuan Phu (Knoxville, TN); Donnelly, Mark (Warrenville, IL); Millard, Cynthia S. (Plainfield, IL); Stols, Lucy (Woodridge, IL)

1999-01-01T23:59:59.000Z

435

Improved Processes to Remove Naphthenic Acids  

Science Conference Proceedings (OSTI)

In the past three years, we followed the work plan as we suggested in the proposal and made every efforts to fulfill the project objectives. Based on our large amount of creative and productive work, including both of experimental and theoretic aspects, we received important technical breakthrough on naphthenic acid removal process and obtained deep insight on catalytic decarboxylation chemistry. In detail, we established an integrated methodology to serve for all of the experimental and theoretical work. Our experimental investigation results in discovery of four type effective catalysts to the reaction of decarboxylation of model carboxylic acid compounds. The adsorption experiment revealed the effectiveness of several solid materials to naphthenic acid adsorption and acidity reduction of crude oil, which can be either natural minerals or synthesized materials. The test with crude oil also received promising results, which can be potentially developed into a practical process for oil industry. The theoretical work predicted several possible catalytic decarboxylation mechanisms that would govern the decarboxylation pathways depending on the type of catalysts being used. The calculation for reaction activation energy was in good agreement with our experimental measurements.

Aihua Zhang; Qisheng Ma; Kangshi Wang; Yongchun Tang; William A. Goddard

2005-12-09T23:59:59.000Z

436

Corrosion free phosphoric acid fuel cell  

DOE Patents (OSTI)

A phosphoric acid fuel cell with an electrolyte fuel system which supplies electrolyte via a wick disposed adjacent a cathode to an absorbent matrix which transports the electrolyte to portions of the cathode and an anode which overlaps the cathode on all sides to prevent corrosion within the cell.

Wright, Maynard K. (Bethel Park, PA)

1990-01-01T23:59:59.000Z

437

Sulfuric acid thermoelectrochemical system and method  

DOE Patents (OSTI)

A thermoelectrochemical system in which an electrical current is generated between a cathode immersed in a concentrated sulfuric acid solution and an anode immersed in an aqueous buffer solution of sodium bisulfate and sodium sulfate. Reactants consumed at the electrodes during the electrochemical reaction are thermochemically regenerated and recycled to the electrodes to provide continuous operation of the system.

Ludwig, Frank A. (Rancho Palos Verdes, CA)

1989-01-01T23:59:59.000Z

438

Therapeutic efficacy of dimercaptosuccinic acid and thiamine/ascorbic acid on lead intoxication in rats  

SciTech Connect

Thiamine, folic acid, pyridoxine and ascorbic acid either individually or in combination have been proven to be effective in reducing the toxic manifestations of lead and in enhancing the antidotal efficacy of CaNa{sub 2}EDTA. In a recent report from the authors' laboratory, it was observed that given combination of thiamine and ascorbic acid with thiol chelators improved the ability of the animals to excrete lead thereby reducing body lead burden. In view of the beneficial effect of these two vitamins, it was considered of interest to evaluate their potential to modify the prophylactic action of DMS in lead intoxication in rat after repeated administration.

Tandon, S.K.; Flora, S.J.S. (Industrial Toxicology Research Centre, Lucknow (India))

1989-11-01T23:59:59.000Z

439

Reaction of Calcite and Dolomite with In-Situ Gelled Acids, Organic Acids, and Environmentally Friendly Chelating Agent (GLDA)  

E-Print Network (OSTI)

Well stimulation is the treatment remedy when oil/gas productivity decreases to unacceptable economical limits. Well stimulation can be carried out through either "Matrix Acidizing" or fracturing with both "Hydraulic Fracturing" and "Acid Fracturing" techniques. "Matrix Acidizing" and "Acid Fracturing" applications involve injecting an acid to react with the formation and dissolve some of the minerals present and recover or increase the permeability. The permeability enhancement is achieved by creating conductive channels "wormholes" in case of "Matrix Acidizing" or creating uneven etching pattern in case of "Acid Fracturing" treatments. In both cases, and to design a treatment successfully, it is necessary to determine the distance that the live acid will be able to penetrate inside the formation, which in turn, determines the volume of the acid needed to carry out the treatment. This distance can be obtained through lab experiments, if formation cores are available, or estimated by modeling the treatment. The successful model will depend on several chemical and physical processes that take place including: the acid transport to the surface of the rock, the speed of the reaction of the acid with the rock, which is often referred to as "Reaction Rate", and the acid leak-off. The parameters describing these processes such as acid diffusion coefficient and reaction kinetics have to be determined experimentally to ensure accurate and reliable modeling. Hydrochloric acid and simple organic acids such as acetic and citric acids have been used extensively for stimulation treatments. The diffusion and reaction kinetics of these acids, in a straight form, were investigated thoroughly in literature. However, solely these acids are used in a simple form in the field. Acid systems such as gelled, crosslinked gelled, surfactant-based, foam-based, or emulsified acids are used to either retard the reaction rate or to enhance acid diversion. Literature review shows that additional work is needed to understand the reaction and report the diffusion and kinetics of these systems with carbonate. In addition, a new chelating agent (GLDA) was recently introduced as a stand-alone stimulating fluid. The kinetics and the mass transfer properties of this acid were not studied before. Therefore, the objective of this work is to study the reaction of different acid systems with calcite and dolomite and report the mass transport and kinetic data experimentally. Lactic acid, a chelating agent (GLDA), and in-situ gelled HCl-formic acids were investigated in this study. In some cases, rheology measurements and core flood experiments were conducted. The data were combined with the reaction study to understand the behavior of these acids and examine their efficiency if injected in the formation.

Rabie, Ahmed 1978-

2012-12-01T23:59:59.000Z

440

A First Look at Yeast Fatty Acid Synthase  

NLE Websites -- All DOE Office Websites (Extended Search)

A First Look at Yeast Fatty Acid Synthase Print A First Look at Yeast Fatty Acid Synthase Print Fatty acids are the major constituents of eukaryotic and bacterial cellular membranes. They are used for functionally important post-translational protein modifications, and chains of fatty acids are the main storage compartments of an organism's chemical energy. Fatty acid synthesis is carried out by fatty acid sythase (FAS), which catalyzes cycles of multistep chemical reactions that are essentially the same in all organisms. FAS uses one acetyl-coenzyme A (CoA) and seven malonyl-CoA molecules to synthesize the 16-carbon palmitic acid, the most abundant fatty acid in eukaryotes. Now, for the first time, a group of researchers has determined the atomic structure of yeast Saccharomyces cerevisiae FAS derived from two crystals of the enzyme, using data collected at ALS Beamlines 8.2.1 and 8.2.2, as well as other synchrotron facilities.

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Acid-catalyzed dehydrogenation of amine-boranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Acid-catalyzed dehydrogenation of amine-boranes Acid-catalyzed dehydrogenation of amine-boranes Acid-catalyzed dehydrogenation of amine-boranes A method of dehydrogenating an amine-borane using an acid-catalyzed reaction. June 25, 2013 Acid-catalyzed dehydrogenation of amine-boranes A method of dehydrogenating an amine-borane using an acid-catalyzed reaction. Available for thumbnail of Feynman Center (505) 665-9090 Email Acid-catalyzed dehydrogenation of amine-boranes A method of dehydrogenating an amine-borane using an acid-catalyzed reaction. The method generates hydrogen and produces a solid polymeric product. The method of dehydrogenating amine-boranes may be used to generate hydrogen for power generation sources such as fuel cells. U.S. Patent No.: 7,645,902 (DOE S-104,909) Patent Application Filing Date: June 22, 2006

442

A First Look at Yeast Fatty Acid Synthase  

NLE Websites -- All DOE Office Websites (Extended Search)

A First Look at Yeast Fatty Acid Synthase Print A First Look at Yeast Fatty Acid Synthase Print Fatty acids are the major constituents of eukaryotic and bacterial cellular membranes. They are used for functionally important post-translational protein modifications, and chains of fatty acids are the main storage compartments of an organism's chemical energy. Fatty acid synthesis is carried out by fatty acid sythase (FAS), which catalyzes cycles of multistep chemical reactions that are essentially the same in all organisms. FAS uses one acetyl-coenzyme A (CoA) and seven malonyl-CoA molecules to synthesize the 16-carbon palmitic acid, the most abundant fatty acid in eukaryotes. Now, for the first time, a group of researchers has determined the atomic structure of yeast Saccharomyces cerevisiae FAS derived from two crystals of the enzyme, using data collected at ALS Beamlines 8.2.1 and 8.2.2, as well as other synchrotron facilities.

443

trans Fatty acid content of foods in China  

Science Conference Proceedings (OSTI)

Growing evidence that dietary consumption of trans fatty acid (TFA) increases the risk of cardiovascular disease has made TFA a hot topic among people, food industries, and government officials in China. trans Fatty acid content of foods in China

444

Method for identifying and quantifying nucleic acid sequence aberrations  

DOE Patents (OSTI)

A method for detecting nucleic acid sequence aberrations by detecting nucleic acid sequences having both a first and a second nucleic acid sequence type, the presence of the first and second sequence type on the same nucleic acid sequence indicating the presence of a nucleic acid sequence aberration. The method uses a first hybridization probe which includes a nucleic acid sequence that is complementary to a first sequence type and a first complexing agent capable of attaching to a second complexing agent and a second hybridization probe which includes a nucleic acid sequence that selectively hybridizes to the second nucleic acid sequence type over the first sequence type and includes a detectable marker for detecting the second hybridization probe.

Lucas, Joe N. (San Ramon, CA); Straume, Tore (Tracy, CA); Bogen, Kenneth T. (Walnut Creek, CA)

1998-01-01T23:59:59.000Z

445

Pressure Acid Leaching Vanadium from Stone coal - Programmaster ...  

Science Conference Proceedings (OSTI)

Vanadium extraction from stone-coal was investigated by pressure acid ... The results show that with the leaching time for 3~4h, temperature at 150?, sulfuric acid consumption of 25%~30%, ... Calcium Reductants A historical review.

446

Lubrication from mixture of boric acid with oils and greases  

DOE Patents (OSTI)

Lubricating compositions including crystalline boric acid and a base lubricant selected from oils, greases and the like. The lubricity of conventional oils and greases can also be improved by adding concentrates of boric acid.

Erdemir, Ali (Naperville, IL)

1995-01-01T23:59:59.000Z

447

Nucleic acid based fluorescent sensor for copper detection  

DOE Patents (OSTI)

A nucleic acid enzyme responsive to copper, comprising an oligonucleotide comprising a nucleotide sequence of SEQ ID NO:1, wherein the nucleic acid enzyme is not self-cleaving.

Lu, Yi; Liu, Juewen

2013-04-02T23:59:59.000Z

448

Improved Processes to Remove Naphthenic Acids  

NLE Websites -- All DOE Office Websites (Extended Search)

Improved Processes to Remove Naphthenic Acids Improved Processes to Remove Naphthenic Acids Final Technical Report (From October 1, 2002 to September 30, 2005) Principle Authors Aihua Zhang, Qisheng Ma, Kangshi Wang, Yongchun Tang (co-PI), William A. Goddard (PI), Date Report was issued: December 9, 2005 DOE Award number: DE-FC26-02NT15383 Name and Address of Submitting Organization California Institute of Technology 1200 East California Blvd., Pasadena, CA91125 Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any

449

Nucleic Acid Standards - Sugar and Phosphate Constituents  

NLE Websites -- All DOE Office Websites (Extended Search)

Sugar and Phosphate Constituents Sugar and Phosphate Constituents The following tables contain the complete references for the structures used in a statistical survey of well-refined mononucleoside, mononucleotide, dinucleoside monophosphate, and trinucleoside diphosphate crystal structures found in the Cambridge Structural Database and the Nucleic Acid Database that appeared in The Journal of the American Chemical Society (Anke Gelbin, Bohdan Schneider, Lester Clowney, Shu-Hsin Hsieh, Wilma K. Olson, and Helen M. Berman. "Geometric Parameters in Nucleic Acids: Sugar Phosphate Constituents" (1996) 118, 519-529.) Table 1: References for Mononucleoside and Mononucleotide Structures Table 2: References for Dinucleoside Monophosphate and Trinucleoside Diphosphate Structures The following tables are summaries of the bond lengths, angles, and torsion

450

Sulfate and acid resistant concrete and mortar  

DOE Patents (OSTI)

The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance. 6 figs.

Liskowitz, J.W.; Wecharatana, M.; Jaturapitakkul, C.; Cerkanowicz, A.E.

1998-06-30T23:59:59.000Z

451

Closure device for lead-acid batteries  

DOE Patents (OSTI)

A closure device for lead-acid batteries includes a filter of granulated activated carbon treated to be hydrophobic combined with means for preventing explosion of emitted hydrogen and oxygen gas. The explosion prevention means includes a vertical open-end tube within the closure housing for maintaining a liquid level above side wall openings in an adjacent closed end tube. Gases vent from the battery through a nozzle directed inside the closed end tube against an impingement surface to remove acid droplets. The gases then flow through the side wall openings and the liquid level to quench any possible ignition prior to entering the activated carbon filter. A wick in the activated carbon filter conducts condensed liquid back to the closure housing to replenish the liquid level limited by the open-end tube.

Ledjeff, Konstantin (Schwalbach, DE)

1983-01-01T23:59:59.000Z

452

Lightweight, durable lead-acid batteries  

Science Conference Proceedings (OSTI)

A lightweight, durable lead-acid battery is disclosed. Alternative electrode materials and configurations are used to reduce weight, to increase material utilization and to extend service life. The electrode can include a current collector having a buffer layer in contact with the current collector and an electrochemically active material in contact with the buffer layer. In one form, the buffer layer includes a carbide, and the current collector includes carbon fibers having the buffer layer. The buffer layer can include a carbide and/or a noble metal selected from of gold, silver, tantalum, platinum, palladium and rhodium. When the electrode is to be used in a lead-acid battery, the electrochemically active material is selected from metallic lead (for a negative electrode) or lead peroxide (for a positive electrode).

Lara-Curzio, Edgar (Lenoir City, TN); An, Ke (Knoxville, TX); Kiggans, Jr., James O. (Oak Ridge, TN); Dudney, Nancy J. (Knoxville, TN); Contescu, Cristian I. (Knoxville, TN); Baker, Frederick S. (Oak Ridge, TN); Armstrong, Beth L. (Clinton, TN)

2011-09-13T23:59:59.000Z

453

Lightweight, durable lead-acid batteries  

DOE Patents (OSTI)

A lightweight, durable lead-acid battery is disclosed. Alternative electrode materials and configurations are used to reduce weight, to increase material utilization and to extend service life. The electrode can include a current collector having a buffer layer in contact with the current collector and an electrochemically active material in contact with the buffer layer. In one form, the buffer layer includes a carbide, and the current collector includes carbon fibers having the buffer layer. The buffer layer can include a carbide and/or a noble metal selected from of gold, silver, tantalum, platinum, palladium and rhodium. When the electrode is to be used in a lead-acid battery, the electrochemically active material is selected from metallic lead (for a negative electrode) or lead peroxide (for a positive electrode).

Lara-Curzio, Edgar; An, Ke; Kiggans, Jr., James O; Dudney, Nancy J; Contescu, Cristian I; Baker, Frederick S; Armstrong, Beth L

2013-05-21T23:59:59.000Z

454

Sulfate and acid resistant concrete and mortar  

DOE Patents (OSTI)

The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance.

Liskowitz, John W. (Belle Mead, NJ); Wecharatana, Methi (Parsippany, NJ); Jaturapitakkul, Chai (Bangkok, TH); Cerkanowicz, deceased, Anthony E. (late of Livingston, NJ)

1998-01-01T23:59:59.000Z

455

PROCESS FOR PRODUCING ALKYL ORTHOPHOSPHORIC ACID EXTRACTANTS  

DOE Patents (OSTI)

A process is given for producing superior alkyl orthophosphoric acid extractants for use in solvent extraction methods to recover and purify various metals such as uranium and vanadium. The process comprises slurrying P/sub 2/O/ sub 5/ in a solvent diluent such as kerosene, benzene, isopropyl ether, and the like. An alipbatic alcohol having from nine to seventeen carbon atoms, and w- hcrein ihc OH group is situated inward of the terminal carbon atoms, is added to the slurry while the reaction temperature is mainiained below 60 deg C. The alcohol is added in the mole ratio of about 2 to l, alcohol to P/sub 2/O/sub 5/. A pyrophosphate reaotion product is formed in the slurry-alcohol mixture. Subsequently, the pyrophosphate reaction product is hydrolyzed with dilute mineral acid to produce the desired alkyl orthophosphoric aeid extractant. The extraetant may then be separated and utilized in metal-recovery, solvent- extraction processes. (AEC)

Grinstead, R.R.

1962-01-23T23:59:59.000Z

456

Acid treatment removes zinc sulfide scale restriction  

Science Conference Proceedings (OSTI)

This paper reports that removal of zinc sulfide (ZnS) scale with acid restored an offshore Louisiana well's production to original rates. The zinc sulfide scale was determined to be in the near well bore area. The selected acid had been proven to control iron sulfide (FeS) scales in sour wells without causing harm to surface production equipment, tubing, and other downhole hardware. The successful removal of the blockage re-established previous production rates with a 105% increase in flowing tubing pressure. On production for a number of months, a high rate, high-pressure offshore well was experiencing unusually rapid pressure and rate declines. A small sample of the restrictive material was obtained during the wire line operations. The well was subsequently shut in while a laboratory analysis determined that zinc sulfide was the major component of the obstruction.

Biggs, K. (Kerr McGee Corp., Lafayette, LA (US)); Allison, D. (Otis Engineering Corp., Lafayette, LA (US)); Ford, W.G.F. (Halliburton Co., Duncan, OK (United States))

1992-08-31T23:59:59.000Z

457

Nucleic acids, compositions and uses thereof  

DOE Patents (OSTI)

The subject invention provides at least one nucleic acid sequence encoding an aldouronate-utilization regulon isolated from Paenibacillus sp. strain JDR-2, a bacterium which efficiently utilizes xylan and metabolizes aldouronates (methylglucuronoxylosaccharides). The subject invention also provides a means for providing a coordinately regulated process in which xylan depolymerization and product assimilation are coupled in Paenibacillus sp. strain JDR-2 to provide a favorable system for the conversion of lignocellulosic biomass to biobased products. Additionally, the nucleic acid sequences encoding the aldouronate-utilization regulon can be used to transform other bacteria to form organisms capable of producing a desired product (e.g., ethanol, 1-butanol, acetoin, 2,3-butanediol, 1,3-propanediol, succinate, lactate, acetate, malate or alanine) from lignocellulosic biomass.

Preston, III, James F. (Micanopy, FL); Chow, Virginia (Gainesville, FL); Nong, Guang (Gainesville, FL); Rice, John D. (Gainesville, FL); St. John, Franz J. (Baltimore, MD)

2012-02-21T23:59:59.000Z

458

IMPROVED PROCESSES TO REMOVE NAPHTHENIC ACIDS  

Science Conference Proceedings (OSTI)

In the second year of this project, we continued our effort to develop low temperature decarboxylation catalysts and investigate the behavior of these catalysts at different reaction conditions. We conducted a large number of dynamic measurements with crude oil and model compounds to obtain the information at different reaction stages, which was scheduled as the Task2 in our work plan. We developed a novel adsorption method to remove naphthenic acid from crude oil using naturally occurring materials such as clays. Our results show promise as an industrial application. The theoretical modeling proposed several possible reaction pathways and predicted the reactivity depending on the catalysts employed. From all of these studies, we obtained more comprehensive understanding about catalytic decarboxylation and oil upgrading based on the naphthenic acid removal concept.

Aihua Zhang; Qisheng Ma; Kangshi Wang, William A. Goddard, Yongchun Tang

2005-05-05T23:59:59.000Z

459

Preconditioner and convergence study for the Quantum Computer Aided Design (QCAD) nonlinear poisson problem posed on the Ottawa Flat 270 design geometry.  

SciTech Connect

A numerical study aimed to evaluate different preconditioners within the Trilinos Ifpack and ML packages for the Quantum Computer Aided Design (QCAD) non-linear Poisson problem implemented within the Albany code base and posed on the Ottawa Flat 270 design geometry is performed. This study led to some new development of Albany that allows the user to select an ML preconditioner with Zoltan repartitioning based on nodal coordinates, which is summarized. Convergence of the numerical solutions computed within the QCAD computational suite with successive mesh refinement is examined in two metrics, the mean value of the solution (an L{sup 1} norm) and the field integral of the solution (L{sup 2} norm).

Kalashnikova, Irina

2012-05-01T23:59:59.000Z

460

Influence of the nucleon-nucleon collision geometry on the determination of the nuclear modification factor for nucleon-nucleus and nucleus-nucleus collisions  

Science Conference Proceedings (OSTI)

The influence of the underlying nucleon-nucleon collision geometry on evaluations of the nuclear overlap function (TAB) and number of binary collisions (Ncoll) is studied. A narrowing of the spatial distribution of the hard-partons with large light-cone fraction x in nucleons leads to a downward correction for Ncoll and TAB, which in turn, results in an upward correction for the nuclear modification factor RAB. The size of this correction is estimated for several experimentally motivated nucleon-nucleon overlap functions for hard-partons. It is found to be significant in peripheral nucleus-nucleus and nucleon-nucleus collisions, and is much larger at the LHC energy of {radical}s = 5.5 TeV than for the RHIC energy of {radical}s = 200 GeV. The implications for experimental measurements are also discussed.

Jia, J.i.

2009-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "acid base-pair geometry" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

The Influence of the Linker Geometry in Bis(3-hydroxy-N-methyl-pyridin-2-one) Ligands on Solution-Phase Uranyl Affinity  

SciTech Connect

Seven water-soluble, tetradentate bis(3-hydroxy-N-methyl-pyridin-2-one) (bis-Me-3,2-HOPO) ligands were synthesized that vary only in linker geometry and rigidity. Solution phase thermodynamic measurements were conducted between pH 1.6 and pH 9.0 to determine the effects of these variations on proton and uranyl cation affinity. Proton affinity decreases by introduction of the solubilizing triethylene glycol group as compared to un-substituted reference ligands. Uranyl affinity was found to follow no discernable trends with incremental geometric modification. The butyl-linked 4Li-Me-3,2-HOPO ligand exhibited the highest uranyl affinity, consistent with prior in vivo decorporation results. Of the rigidly-linked ligands, the o-phenylene linker imparted the best uranyl affinity to the bis-Me-3,2-HOPO ligand platform.

Szigethy, Geza; Raymond, Kenneth

2010-08-12T23:59:59.000Z

462

Effects of temperature, humidity, sample geometry, and other variables on Bruceton type 12 impact initiation of HMX-based high explosives  

SciTech Connect

The drop weight impact test, developed at Bruceton Naval Research Laboratory 60 years ago, is still the most commonly used configuration for evaluating sensitivity of explosives to non-shock ignition. The standard drop weight impact test is performed under ambient conditions for temperature and humidity - variations in which are known to significantly affect the probability of reaction. We have performed a series of impact tests in an attempt to characterize the effect of temperature, humidity, sample geometry (height, mass, L/d, and pressed density), sample confinement, and impact surface properties (strength and coefficient of friction) on the probabil