Udegbunam, E.O.; Huff, B.G. [Illinois State Geological Survey, Champaign, IL (United States)
1994-12-31
Geological characterizations, modeling and 3-D computer-generated visualizations of the Ordovician St. Peter Sandstone at the Hillsboro Gas Storage field in Montgomery County, Illinois, are discussed. Petrophysical analyses reveal four distinct hydraulic flow units in six cored wells. Furthermore, four lithologies, identified by thin section petrography, are associated with the various hydraulic units. Fieldwide visualizations of 3-D distributions of petrophysically-derived attributes reservoir quality index (RQI) and flow zone indicator (FZI) -- show considerable vertical variability but lateral continuity. This finding explains why it is easier to expand the gas bubble laterally than vertically. Advantages of the 3-D reservoir description of Hillsboro Gas Storage field include (1) improved definition of the spatial porosity distribution which leads to better estimation of reservoir volumetrics; (2) improved definition of reservoir hydraulic flow zones; and (3) development of realistic reservoir model(s) for the simulation and management of the gas storage field.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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Category:Goodland, KS | Open Energy Information
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1 KS.Inglett_CV KANIKA SHARMA INGLETT
Balser, Teri C.
; bioremediation and biodegradation of environmental pollutants EDUCATION Ph.D., Soil and Water Science with minor technology. TEACHING Soil and Water Science Department, University of Florida Instructor, Bioremediation1 KS.Inglett_CV KANIKA SHARMA INGLETT Soil and Water Science Department, Ph: (352) 392-1804 ext 223
Bethune, Iain; Carter, Adam; Guo, Xu; Korosoglou, Paschalis
2011-01-01
CP2K is a powerful materials science and computational chemistry code and is widely used by research groups across Europe and beyond. The recent addition of a linear scaling KS-DFT method within the code has made it possible to simulate systems...
Effects of finite volume on the KL – KS mass difference
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Christ, N.? H.; Feng, X.; Martinelli, G.; Sachrajda, C.? T.
2015-06-01
Phenomena that involve two or more on-shell particles are particularly sensitive to the effects of finite volume and require special treatment when computed using lattice QCD. In this paper we generalize the results of Lüscher and Lellouch and Lüscher, which determine the leading-order effects of finite volume on the two-particle spectrum and two-particle decay amplitudes to determine the finite-volume effects in the second-order mixing of the K? and K?? states. We extend the methods of Kim, Sachrajda, and Sharpe to provide a direct, uniform treatment of these three, related, finite-volume corrections. In particular, the leading, finite-volume corrections to the KLmore »– KS mass difference ?MK and the CP-violating parameter ?K are determined, including the potentially large effects which can arise from the near degeneracy of the kaon mass and the energy of a finite-volume, two-pion state.« less
Study of Penguin Pollution in the B^0 -> J/psi K_S Decay
Satoshi Mishima
2007-03-18
We study the penguin pollution in the B^0 -> J/psi K_S decay up to leading power in 1/m_b and to next-to-leading order in \\alpha_s, m_b being the b quark mass and \\alpha_s the strong coupling constant. The deviation \\Delta S_{J/psi K_S} of the mixing-induced CP asymmetry from sin(2\\phi_1) and the direct CP asymmetry A_{J/psi K_S} are both found to be of O(10^{-3}) in a formalism that combines the QCD-improved factorization and perturbative QCD approaches.
Hillsboro, Oregon: Energy Resources | Open Energy Information
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Hillsboro, Texas: Energy Resources | Open Energy Information
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Hillsboro Alternative Energy Fund | Open Energy Information
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Search for Lepton Flavor Violating Decays tau--->l-Ks0 with the BABAR Experiment
Fisher, Peter H.
A search for the lepton flavor violating decays tau--->l-KS0 (l=e or mu) has been performed using a data sample corresponding to an integrated luminosity of 469??fb[superscript -1], collected with the BABAR detector at the ...
Penguin pollution in the B^0 -> J/psi K_S decay
Hsiang-nan Li; Satoshi Mishima
2007-03-02
We present the most complete analysis of the penguin correction to the extraction of the standard-model parameter sin(2\\phi_1) from the B^0 -> J/psi K_S decay up to leading power in 1/m_b and to next-to-leading order in \\alpha_s, \\phi_1 being the weak phase, m_b the b quark mass, and \\alpha_s the strong coupling constant. The deviation \\Delta S_{J/psi K_S} of the mixing-induced CP asymmetry from sin(2\\phi_1) and the direct CP asymmetry A_{J/psi K_S} are both found to be of O(10^{-3}) in a formalism that combines the QCD-improved factorization and perturbative QCD approaches. The above results, different from those of O(10^{-4}) and of O(10^{-2}) obtained in the previous calculations, provide an important standard-model reference for verifying new physics from the B^0 -> J/psi K_S data.
Optimal Supplier Choice with Discounting B. Goldengorin, J. Keane, V. Kuzmenko & M. K-S. Tso
Sidorov, Nikita
Optimal Supplier Choice with Discounting B. Goldengorin, J. Keane, V. Kuzmenko & M. K-S. Tso First of Mathematics, The University of Manchester #12;Optimal supplier choice with discounting B Goldengorin, J. Keane suppliers operate discount schedules based on total business value. We formulate the buyers's decision
Observation of B -> K-S(0)pi(+)pi(-) and evidence for B -> K-*+/-pi(-/+)
Ammar, Raymond G.; Besson, David Zeke; Zhao, X.
2002-12-01
We report on a search for charmless hadronic B decays to the three-body final states K(S)(0)h(+)pi(-), K(+)h(-)pi(0), K(S)(0)h(+)pi(0) (h(+/-) denotes a charged pion or kaon), and their charge conjugates, using 13.5 fb(-1) ...
J- and Ks-band Galaxy Counts and Color Distributions in the AKARI North Ecliptic Pole Field
Koji Imai; Hideo Matsuhara; Shinki Oyabu; Takehiko Wada; Toshinobu Takagi; Naofumi Fujishiro; Hitoshi Hanami; Chris P. Pearson
2007-02-09
We present the J- and Ks-band galaxy counts and galaxy colors covering 750 square arcminutes in the deep AKARI North Ecliptic Pole (NEP) field, using the FLoridA Multi-object Imaging Near-ir Grism Observational Spectrometer (FLAMINGOS) on the Kitt Peak National Observatory (KPNO) 2.1m telescope. The limiting magnitudes with a signal-to-noise ratio of three in the deepest regions are 21.85 and 20.15 in the J- and Ks-bands respectively in the Vega magnitude system. The J- and Ks-band galaxy counts in the AKARI NEP field are broadly in good agreement with those of other results in the literature, however we find some indication of a change in the galaxy number count slope at J~19.5 and over the magnitude range 18.0 < Ks < 19.5. We interpret this feature as a change in the dominant population at these magnitudes because we also find an associated change in the B - Ks color distribution at these magnitudes where the number of blue samples in the magnitude range 18.5 < Ks < 19.5 is significantly larger than that of Ks < 17.5.
INTEGRAL observation of the X-ray burster KS 1741-293
G. De Cesare; A. Bazzano; G. Stratta; M. Del Santo; A. Tarana; P. Ubertini
2005-11-30
KS 1741-293 was firstly detected in 1989 with the X-ray wide field camera TTM (3-10 keV) on board of the Rontgen-Kvant-Mir observatory. During these observations this source exhibited two X-ray bursts allowing to identify it as a neutron star in a Low mass X-ray Binary. During the BeppoSAX/WFC monitoring of the Galactic Centre Region, KS 1741-293 was also reported at a flux level of 6 mCrab in the 2-9 keV and 25 mCrab in the 9-25 keV energy range. Thanks to the deep and regular INTEGRAL observation of the Galactic Centre region, KS 1741-293 has been observed by the X-ray monitor JEM-X and the imager IBIS in a wide energy range, giving for the first time relevant information on its high energy behaviour. Furthermore, two X-ray bursts have been detected by JEM-X. We report on IBIS and JEM-X data analysis in terms of flux monitoring, spectral proprieties and bursts detection. The data reduction has been done with the most recent release of the standard analysis software (OSA 5.0).
Observation of a narrow structure in 1 H( ? , KS0 ) X via interference with ? -meson production
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Amaryan, M. J.; Gavalian, G.; Nepali, C.; Polyakov, M. V.; Azimov, Ya.; Briscoe, W. J.; Dodge, G. E.; Hyde, C. E.; Klein, F.; Kuznetsov, V.; et al
2012-03-01
We report observation of a narrow peak structure at ?1.54 GeV with a Gaussian width ? = 6 MeV in the missing mass of KS in the reaction ? + p ? pKSKL. The observed structure may be due to the interference between a strange (or antistrange) baryon resonance in the pKL system and the ?(KSKL) photoproduction leading to the same final state. The statistical significance of the observed excess of events estimated as the log-likelihood ratio of the resonant signal + background hypothesis and the ?-production-based background-only hypothesis corresponds to 5.3?.
Study of KS semileptonic decays and CPT test with the KLOE detector
Daria Kami?ska; for the KLOE-2 Collaboration
2015-09-03
Study of semileptonic decays of neutral kaons allows to perform a test of discrete symmetries, as well as basic principles of the Standard Model. In this paper a general review on dependency between charge asymmetry constructed for semileptonic decays of short- and long-lived kaons and CPT symmetry is given. The current status of determination of charge asymmetry for short-lived kaon, obtained by reconstruction of about 10^5 KS -> pen decays collected at DAFNE with the KLOE detector is also reviewed.
DOE - Office of Legacy Management -- Spencer Chemical Co - KS 0-01
Office of Legacy Management (LM)
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Control of Well KS-8 in the Kilauea Lower East Rift Zone | Open Energy
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Detection of Ks-excess stars in the 14Myr open cluster NGC4755
Bonatto, C; Ortolani, S; Barbuy, B
2006-01-01
We derive the structure, distribution of MS and PMS stars and dynamical state of the young open cluster NGC 4755. We explore the possibility that, at the cluster age, some MS and PMS stars still present infrared excesses related to dust envelopes and proto-planetary discs. The radial density profile follows King's law with a core radius $\\rm\\rc=0.7\\pm0.1 pc$ and a limiting radius $\\rm\\rl=6.9\\pm0.1 pc$; the cluster age is $\\rm14\\pm2 Myr$. Field-star decontamination reveals a low-MS limit at $\\rm\\approx1.4 \\ms$. The core MF ($\\chi=0.94\\pm0.16$) is flatter than the halo's ($\\chi=1.58\\pm0.11$). NGC 4755 contains $\\rm\\sim285$ candidate PMS stars of age $\\rm\\sim1 - 15 Myr$, and a few evolved stars. The mass locked up in PMS, MS and evolved stars amounts to $\\rm\\sim1150 \\ms$. Proper motions show that \\ks-excess MS and PMS stars are cluster members. \\ks-excess fractions in PMS and MS stars are $\\rm5.4\\pm2.1%$ and $\\rm3.9\\pm1.5%$ respectively, consistent with the cluster age. The core is deficient in PMS stars, as com...
Optical observations of Be/X-ray transient system KS 1947+300
U. Kiziloglu; A. Baykal; N. Kiziloglu
2006-08-05
ROTSE-IIId observations of the Be/X-ray transient system KS 1947+300 obtained between September 2004 and December 2005 make it possible to study the correlation between optical and X-ray activity. The optical outburst of 0.1 mag was accompanied by an increase in X-ray flux in 2004 observations. Strong correlation between the optical and X-ray light curves suggests that neutron star directly accretes from the outflowing material of Be star. The nearly zero time lag between X-ray and optical light curves suggests a heating of the disk of Be star by X-rays. No optical brightening and X-ray enhancement was seen in 2005 observations. There is no indication of the orbital modulation in the optical light curve.
Recent aeolian dune change on Mars M.C. Bourke a,b,, K.S. Edgett c
Bourke, Mary C.
Recent aeolian dune change on Mars M.C. Bourke a,b,, K.S. Edgett c , B.A. Cantor c a Planetary 2007 Abstract Previous comparisons of Martian aeolian dunes in satellite images have not detected any change in dune form or position. Here, we show dome dunes in the north polar region that shrank
Detection of Ks-band Thermal Emission from WASP-3b
Zhao, Ming; Barman, Travis; Hinkley, Sasha; Swain, Mark R; Wright, Jason; Monnier, John D
2012-01-01
We report the detection of thermal emission from the hot Jupiter WASP-3b in the KS band, using a newly developed guiding scheme for the WIRC instrument at the Palomar Hale 200in telescope. Our new guiding scheme has improved the telescope guiding precision by a factor of ~5-7, significantly reducing the correlated systematics in the measured light curves. This results in the detection of a secondary eclipse with depth of 0.181%\\pm0.020% (9-{\\sigma}) - a significant improvement in WIRC's photometric precision and a demonstration of the capability of Palomar/WIRC to produce high quality measurements of exoplanetary atmospheres. Our measured eclipse depth cannot be explained by model atmospheres with heat redistribution but favor a pure radiative equilibrium case with no redistribution across the surface of the planet. Our measurement also gives an eclipse phase center of 0.5045\\pm0.0020, corresponding to an ecos{\\omega} of 0.0070\\pm0.0032. This result is consistent with a circular orbit, although it also sugges...
Karliner, Marek; Lipkin, Harry J
ar X iv :h ep -p h/ 05 06 08 4v 3 1 6 Ju n 20 05 Cavendish-HEP-05/09 TAUP 2807/05 ANL-HEP-PR-05-47 Isospin Analysis of ?+ production forbids ?p ? ?+ Ks and allows ?n ? ?+ K? Marek Karliner a,b? and Harry J. Lipkin b,c† a Cavendish Laboratory... +Ks n|T † |K+K?p? ?K+K?p|T |?p? Im ?K+K?n| T |?n? = ? ?K+K?n| T † |K+K?n? ?K+K?n| T |?n? (5) We now see that the transition matrix ?K+Ksn| T |?p? is proportional to the transition matrix ?K+Ksn|T † |K+K?p?, where the ?(1520) can appear as a resonance...
Energy Department Recognizes Cities of Beaverton and Hillsboro...
Buildings Challenge partners are showing other cities and school districts how they can save money by saving energy and protect the environment." Beaverton is making significant...
Hillsboro Beach, Florida: Energy Resources | Open Energy Information
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Hillsboro Pines, Florida: Energy Resources | Open Energy Information
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Hillsboro Ranches, Florida: Energy Resources | Open Energy Information
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City of Hillsboro, North Dakota (Utility Company) | Open Energy Information
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City of Hillsboro, Kansas (Utility Company) | Open Energy Information
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Energy Department Recognizes Cities of Beaverton and Hillsboro, Oregon,
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
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Workplace Charging Challenge Partner: City of Hillsboro | Department of
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on DeliciousMathematics And Statistics Â» USAJobs SearchAMERICA'SEnergy Safely TearEnergyCignaEnergy
Boundaries and Topological Algorithms
Fleck, Margaret Morrison
1988-09-01
This thesis develops a model for the topological structure of situations. In this model, the topological structure of space is altered by the presence or absence of boundaries, such as those at the edges of objects. ...
Observation of a narrow structure in 1H(?,KS0)X via interference with phi-meson production
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Amaryan, M J; Nepali, C; Polyakov, M V; Azimov, Ya; Briscoe, W J; Dodge, G E; Hyde, C E; Klein, F; Kuznetsov, V; Strakovsky, I
2012-03-21
We report observation of a narrow peak structure at ?1.54 GeV with a Gaussian width ? = 6 MeV in the missing mass of KS in the reaction ? + p ? pKSKL. The observed structure may be due to the interference between a strange (or antistrange) baryon resonance in the pKL system and the ?(KSKL) photoproduction leading to the same final state. The statistical significance of the observed excess of events estimated as the log-likelihood ratio of the resonant signal + background hypothesis and the ?-production-based background-only hypothesis corresponds to 5.3?.
Aslanyan, P Z
2005-01-01
Experimental data from the 2m propane bubble chamber for production of $\\Lambda$, $K^0_s$ have been used to search of exotic baryon states, in the $K_s^0 p$, $K_s^0 \\Lambda$ and $\\Lambda p$ decay mode for the reaction p+propane at 10 GeV/c. The estimation of experimental inclusive cross sections for $\\Lambda$ and $K^0_s$ production in the p$^{12}C$ collision is equal to $\\sigma_{\\Lambda}$= 13.3$\\pm$1.7 mb and $\\sigma_{K^0_s}$= 3.8$\\pm$0.6 mb, respectively. The measured $\\Lambda /\\pi^+$ ratio from pC reaction is equal to (5.3$\\pm0.8)*10^{-2}$. The experimental $\\Lambda /\\pi^+$ ratio from the pC reaction is approximately two times larger than the $\\Lambda /\\pi^+$ ratio simulated by FRITIOF model from the pC reaction. The invariant mass spectrum $\\Lambda K^0_s$ registered narrow peaks in regions of 1750 and 1795 MeV/$c^2$. The statistical significance of these peaks has been estimated as 5.6 and 3.3 S.D., respectively. These would be candidates for the $N^0$ or the $\\Xi^0$ pentaquark states. The $pK^0_s$ invaria...
P. Zh. Aslanyan
2005-11-09
Experimental data from the 2m propane bubble chamber for production of $\\Lambda$, $K^0_s$ have been used to search of exotic baryon states, in the $K_s^0 p$, $K_s^0 \\Lambda$ and $\\Lambda p$ decay mode for the reaction p+propane at 10 GeV/c. The estimation of experimental inclusive cross sections for $\\Lambda$ and $K^0_s$ production in the p$^{12}C$ collision is equal to $\\sigma_{\\Lambda}$= 13.3$\\pm$1.7 mb and $\\sigma_{K^0_s}$= 3.8$\\pm$0.6 mb, respectively. The measured $\\Lambda /\\pi^+$ ratio from pC reaction is equal to (5.3$\\pm0.8)*10^{-2}$. The experimental $\\Lambda /\\pi^+$ ratio from the pC reaction is approximately two times larger than the $\\Lambda /\\pi^+$ ratio simulated by FRITIOF model from the pC reaction. The invariant mass spectrum $\\Lambda K^0_s$ registered narrow peaks in regions of 1750 and 1795 MeV/$c^2$. The statistical significance of these peaks has been estimated as 5.6 and 3.3 S.D., respectively. These would be candidates for the $N^0$ or the $\\Xi^0$ pentaquark states. The $pK^0_s$ invariant mass spectrum shows resonant structures with $M_{K_s^0 p}$=1540, 1613, 1821 MeV/$c^2$. The statistical significance of these peaks have been estimated as 5.5,4.8 and 5.0 s.d., respectively. The invariant mass spectrum S=-1 $\\Lambda p$ observed a narrow peaks at 2100, 2175,2285 and 2353 MeV/$c^2$. Their excess above background by the second method is 6.9, 4.9, 3.8 and 2.9 S.D., respectively.
First measurement of ?? with a model-independent Dalitz plot analysis of B±?DK±, D?KS????? decay
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aihara, H.; Arinstein, K.; Asner, D. M.; Aulchenko, V.; Aushev, T.; Bakich, A. M.; Belous, K.; Bhuyan, B.; Bischofberger, M.; Bondar, A.; et al
2012-06-26
We present the first measurement of the angle ?? of the unitarity triangle using a model-independent Dalitz plot analysis of B±?DK±, D?KS????? decays. The method uses, as input, measurements of the strong phase of the D?K?S???? amplitude from the CLEO Collaboration. The result is based on the full data set of 772×106 BB¯¯¯ pairs collected by the Belle experiment at the ?(4S) resonance. We obtain ??=(77.3+15.1–14.9±4.1±4.3)° and the suppressed amplitude ratio rB=0.145±0.030±0.010±0.011. Here the first error is statistical, the second is the experimental systematic uncertainty, and the third is the error due to the precision of the strong-phase parameters obtainedmore »by CLEO.« less
First measurement of ?? with a model-independent Dalitz plot analysis of B±?DK±, D?KS????? decay
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aihara, H.; Arinstein, K.; Asner, D. M.; Aulchenko, V.; Aushev, T.; Bakich, A. M.; Belous, K.; Bhuyan, B.; Bischofberger, M.; Bondar, A.; Bonvicini, G.; Bozek, A.; Bra?ko, M.; Browder, T. E.; Chang, M.-C.; Chang, P.; Cheon, B. G.; Chilikin, K.; Chistov, R.; Cho, K.; Choi, Y.; Dalseno, J.; Doležal, Z.; Drutskoy, A.; Eidelman, S.; Epifanov, D.; Fast, J. E.; Feindt, M.; Gaur, V.; Gabyshev, N.; Garmash, A.; Goh, Y. M.; Golob, B.; Haba, J.; Hayashii, H.; Horii, Y.; Hoshi, Y.; Hou, W.-S.; Hsiung, Y. B.; Hyun, H. J.; Iijima, T.; Ishikawa, A.; Itoh, R.; Iwabuchi, M.; Julius, T.; Kang, J. H.; Kawasaki, T.; Kiesling, C.; Kim, H. J.; Kim, H. O.; Kim, J. B.; Kim, J. H.; Kim, K. T.; Kim, M. J.; Kim, Y. J.; Kinoshita, K.; Ko, B. R.; Koblitz, S.; Kodyš, P.; Korpar, S.; Križan, P.; Krokovny, P.; Kronenbitter, B.; Kuhr, T.; Kumita, T.; Kuzmin, A.; Kwon, Y.-J.; Lee, S.-H.; Li, J.; Li, Y.; Libby, J.; Liu, C.; Liu, Y.; Liu, Z. Q.; Liventsev, D.; Louvot, R.; Matvienko, D.; Miyabayashi, K.; Miyata, H.; Mizuk, R.; Mohanty, G. B.; Moll, A.; Mori, T.; Muramatsu, N.; Nagasaka, Y.; Nakano, E.; Nakao, M.; Natkaniec, Z.; Nishida, S.; Nitoh, O.; Ogawa, S.; Ohshima, T.; Okuno, S.; Olsen, S. L.; Pakhlova, G.; Park, C. W.; Park, H.; Park, H. K.; Park, K. S.; Pedlar, T. K.; Pestotnik, R.; Petri?, M.; Piilonen, L. E.; Poluektov, A.; Prothmann, K.; Ritter, M.; Röhrken, M.; Rozanska, M.; Ryu, S.; Sahoo, H.; Sakai, Y.; Sanuki, T.; Sato, Y.; Schneider, O.; Schwanda, C.; Schwartz, A. J.; Senyo, K.; Seon, O.; Sevior, M. E.; Shapkin, M.; Shibata, T.-A.; Shiu, J.-G.; Shwartz, B.; Sibidanov, A.; Simon, F.; Singh, J. B.; Smerkol, P.; Sohn, Y.-S.; Sokolov, A.; Solovieva, E.; Stani?, S.; Stari?, M.; Sumisawa, K.; Sumiyoshi, T.; Tatishvili, G.; Trabelsi, K.; Uchida, M.; Uehara, S.; Unno, Y.; Uno, S.; Urquijo, P.; Vanhoefer, P.; Varner, G.; Varvell, K. E.; Vinokurova, A.; Vorobyev, V.; Wang, C. H.; Wang, M.-Z.; Wang, P.; Watanabe, Y.; Williams, K. M.; Won, E.; Yabsley, B. D.; Yamamoto, H.; Yamaoka, J.; Yamashita, Y.; Yuan, C. Z.; Zhang, Z. P.; Zhilich, V.; Zhulanov, V.; Zupanc, A.
2012-06-01
We present the first measurement of the angle ?? of the unitarity triangle using a model-independent Dalitz plot analysis of B±?DK±, D?KS????? decays. The method uses, as input, measurements of the strong phase of the D?K?S???? amplitude from the CLEO Collaboration. The result is based on the full data set of 772×106 BB¯¯¯ pairs collected by the Belle experiment at the ?(4S) resonance. We obtain ??=(77.3+15.1–14.9±4.1±4.3)° and the suppressed amplitude ratio rB=0.145±0.030±0.010±0.011. Here the first error is statistical, the second is the experimental systematic uncertainty, and the third is the error due to the precision of the strong-phase parameters obtained by CLEO.
Disjoint BoundaryBoundary Paths in Critical Circular Planar Networks
Morrow, James A.
Disjoint BoundaryÂBoundary Paths in Critical Circular Planar Networks Ryan Sturgell December 8 that in a critical circular planar network every interior vertex has three disjoint paths to the boundary. 1, 1998 Abstract This paper explores some properties of critical circular planar netÂ works. The main
Southern California, University of
CMR at 3 Tesla using a large flexible surface coil: initial experience KS Nayak, P Varadarajan, C obtained with a flexible receiver coil that generates LV function studies at 3T of diagnostic quality that wraps around the left chest for CMR imaging of the heart at 3 Tesla. Methods: Experiments were performed
Brunnian Braids Boundary Brunnian Braids Main Results Boundary Brunnian braids, mirror reflection
Wu, Jie
Brunnian Braids Boundary Brunnian Braids Main Results Boundary Brunnian braids, mirror reflection December 17, 2007 #12;Brunnian Braids Boundary Brunnian Braids Main Results Boundary Brunnian braids, mirror reflection and the homotopy groups Brunnian Braids Boundary Brunnian Braids Main Results #12
CONTINUED COOLING OF THE CRUST IN THE NEUTRON STAR LOW-MASS X-RAY BINARY KS 1731-260
Cackett, Edward M.; Miller, Jon M.; Brown, Edward F.; Cumming, Andrew; Degenaar, Nathalie; Wijnands, Rudy
2010-10-20
Some neutron star low-mass X-ray binaries have very long outbursts (lasting several years) which can generate a significant amount of heat in the neutron star crust. After the system has returned to quiescence, the crust then thermally relaxes. This provides a rare opportunity to study the thermal properties of neutron star crusts, putting constraints on the thermal conductivity and hence the structure and composition of the crust. KS 1731-260 is one of only four systems where this crustal cooling has been observed. Here, we present a new Chandra observation of this source approximately eight years after the end of the last outburst and four years since the last observation. We find that the source has continued to cool, with the cooling curve displaying a simple power-law decay. This suggests that the crust has not fully thermally relaxed yet and may continue to cool further. A simple power-law decay is in contrast to theoretical cooling models of the crust, which predict that the crust should now have cooled to the same temperature as the neutron star core.
Boundary Degeneracy of Topological Order
Juven Wang; Xiao-Gang Wen
2015-01-15
We introduce the concept of boundary degeneracy of topologically ordered states on a compact orientable spatial manifold with boundaries, and emphasize that the boundary degeneracy provides richer information than the bulk degeneracy. Beyond the bulk-edge correspondence, we find the ground state degeneracy of the fully gapped edge modes depends on boundary gapping conditions. By associating different types of boundary gapping conditions as different ways of particle or quasiparticle condensations on the boundary, we develop an analytic theory of gapped boundaries. By Chern-Simons theory, this allows us to derive the ground state degeneracy formula in terms of boundary gapping conditions, which encodes more than the fusion algebra of fractionalized quasiparticles. We apply our theory to Kitaev's toric code and Levin-Wen string-net models. We predict that the $Z_2$ toric code and $Z_2$ double-semion model (more generally, the $Z_k$ gauge theory and the $U(1)_k \\times U(1)_{-k}$ non-chiral fractional quantum Hall state at even integer $k$) can be numerically and experimentally distinguished, by measuring their boundary degeneracy on an annulus or a cylinder.
. A single nominal 100 watt solar panel for 4 sun hours/day would yield -4 kWh/day or 12 kWh/month. At $2Print http://us.mg4.mail.yahoo.comfneo/launch?.rand=deOsgk04ks40i Subject: Re: [s-w-h] Solar verses wind efficiency From: David Raine (dave@dyocore.com) To: wind4energy@yahoo.com; Date: Thursday
Vacuum Structure and Boundary Renormalization Group
M. Asorey; J. M. Munoz-Castaneda
2007-12-28
The vacuum structure is probed by boundary conditions. The behaviour of thermodynamical quantities like free energy, boundary entropy and entanglement entropy under the boundary renormalization group flow are analysed in 2D conformal field theories. The results show that whereas vacuum energy and boundary entropy turn out to be very sensitive to boundary conditions, the vacuum entanglement entropy is independent of boundary properties when the boundary of the entanglement domain does not overlap the boundary of the physical space. In all cases the second law of thermodynamics holds along the boundary renormalization group flow.
.yahoo.com/neo/launch?.rand=deOsgk04ks40i Subject: RE: [s-w-h] b Solar verses wind efficiency From: Michael Klemen (wind4energy;Print http://us.rng4.mail.yahoo.comlneo/launch?.rand=deOsgko4ks4 energy in the wind is proportional://www.ndsu.edu/ndsu/klemen/Perfect_Turbine.htm You can see that for an ideal real life wind turbine ("good turbine") the increase in energy
Geography 104 Boundary Layer Climates
Geography 104 Boundary Layer Climates Assignment #5 Question 1: The Urban Heat Island The following briefly how the use of giant windmills or fans can be effective in preventing frost in an orchard. Refer
The Mass and Radius of the Neutron Star in the Bulge Low-Mass X-ray Binary KS 1731-260
Feryal Ozel; Andrew Gould; Tolga Guver
2011-04-26
Measurements of neutron star masses and radii are instrumental for determining the equation of state of their interiors, understanding the dividing line between neutron stars and black holes, and for obtaining accurate statistics of source populations in the Galaxy. We report here on the measurement of the mass and radius of the neutron star in the low-mass X-ray binary KS 1731-260. The analysis of the spectroscopic data on multiple thermonuclear bursts yields well-constrained values for the apparent angular area and the Eddington flux of the source, both of which depend in a distinct way on the mass and radius of the neutron star. The binary KS 1731-260 is in the direction of the Galactic bulge, allowing a distance estimate based on the density of stars in that direction. Making use of the Han & Gould model, we determine the probability distribution over the distance to the source, which is peaked at 8 kpc. Combining these measurements, we place a strong upper bound on the radius of the neutron star, R <= 12 km, while confining its mass to M <= 1.8 M_sun.
Building BoundariesTM Information for Parents
California at Santa Cruz, University of
Building BoundariesTM Information for Parents Even very young children can learn some skills of 2 #12;Building BoundariesTM: Information for Parents How to Recognize Warning Signs in Your Child
Boundary learning by optimization with topological constraints
Helmstaedter, Moritz N.
Recent studies have shown that machine learning can improve the accuracy of detecting object boundaries in images. In the standard approach, a boundary detector is trained by minimizing its pixel-level disagreement with ...
First model-independent Dalitz analysis of $B^0 \\to DK^{*0}$, $D\\to K_S^0\\pi^+\\pi^-$ decay
Negishi, K; Yamamoto, H
2015-01-01
We report a measurement of the amplitude ratio $r_S$ of $B^0 \\to D^0K^{*0}$ and $B^0 \\to \\bar{D^0}K^{*0}$ decays with a Dalitz analysis of $D\\to K_S^0\\pi^+\\pi^-$ decays, for the first time using a model-independent method. We set an upper limit $r_S cos(\\delta_S \\pm \\phi_3)$, $y_\\pm = r_S \\sin(\\delta_S \\pm \\phi_3)$ and $\\phi_3~(\\delta_S)$ is the weak (strong) phase difference between $B^0 \\to D^0K^{*0}$ and $B^0 \\to \\bar{D^0}K^{*0}$.
P. Krokovny; for the Belle Collaboration
2006-07-28
We present a measurement of the angle phi1 of the CKM Unitarity Triangle using time-dependent Dalitz analysis of D -> Ks pi+ pi- decays produced in neutral B meson decay to a neutral D meson and a light meson (B0bar -> D(*) h0). The method allows a direct extraction of 2phi1 and, therefore, helps to resolve the ambiguity between 2phi1 and pi-2phi1 in the measurement of sin 2phi1. We obtain sin 2phi1=0.78+-0.44+-0.22 and cos 2phi1=1.87+0.40+0.22 -0.53-0.32 The sign of cos 2phi1 is determined to be positive at 98.3% C.L.
Rohrer, Gregory S.
Validating computed grain boundary energies in fcc metals using the grain boundary character. Since the GBCD is inversely related to the grain boundary energy distribution, it offers a useful metric for validating grain boundary energy calculations. Comparisons between the measured GBCD and calculated energies
Nayak, Krishna
Real-Time Cardiac Imaging at 3 Tesla K.S. NAYAK, C.H. CUNNINGHAM, J.M. SANTOS, J.M. PAULY, AND D are shown in Figure 2. Conclusions We have demonstrated real-time cardiac imaging at 3 Tesla with high SNR
Grain boundaries in coated conductors
Weigand, Marcus
2010-07-06
,757 • Bibliography: 5,087 ix Publications and Conference Presentations This thesis led to the following publications: • M. Weigand, S. C. Speller, G. M. Hughes, N. A. Rutter, S. Lozano-Perez, C. R. M. Grovenor and J. H. Durrell: “Individual grain boundary properties... and overall performance of metal-organic deposition coated conductors ”, Phys. Rev. B 81, 174537 (2010) • R. Hühne, J. Eickemeyer, V. S. Sarma, A. Güth, T. Thersleff, J. Freudenberger, O. de Haas, M. Weigand, J. H. Durrell, L. Schultz and B. Holzapfel: “Ap...
Boundary Layer Cloud Turbulence Characteristics
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 OutreachProductswsicloudwsiclouddenDVA N C E D B L O OLaura|BilayerBiomimeticBooks Are FunBorrowingBrungerBoundary
4.3 Boundary integral equations
2010-10-18
62. CHAPTER 4. OBSTACLE SCATTERING. 4.3 Boundary integral equations. We introduce the equivalent sources for the Helmholtz equation and establish ...
Performance Boundaries in Nb3Sn Superconductors
Godeke, Arno
2006-01-01
Boundaries in Nb 3 Sn Superconductors – Berkeley, CABoundaries in Nb 3 Sn Superconductors – Berkeley, CABoundaries in Nb 3 Sn Superconductors Arno Godeke Berkeley,
Boundary effects on Zircaloy-4 cladding deformation in LOCA simulation tests. [PWR; BWR
Longest, A.W.; Chapman, R.H.; Crowley, J.L.
1982-01-01
Deformation behavior of Zircaloy-4 cladding under simulated loss-of-coolant accident (LOCA) conditions is being investigated in the Multirod Burst Test (MRBT) program in single rod and multirod tests. In these tests, internally-pressurized unirradiated Zircaloy-4 tubes containing internal electrical heaters are heated to failure in a low-pressure, superheated-steam environment (200 < Re < 800). The results provide a data base for evaluating deformation and blockage models employed with design-basis accident sequences to assess LWR core coolability for licensing purposes. Results of a recent 8 X 8 test indicate that models derived from smaller test arrays may not be representative of the behavior in large arrays, particularly for those temperature ranges in which large deformation can be expected. Two MRBT LOCA simulation tests conducted under the same nominal conditions (approx. 10 K/s heating rate from approx. 340/sup 0/C to failure at approx. 770/sup 0/C) were examined to determine the effects of array size and boundary conditions on deformation.
Measuring Chemical Loadings through Inlets: Hillsboro and Boca Raton Inlets (Florida, USA)
the relative contributions of pollutants from these sources has become an important topic in coastal management implicated as pollution sources impacting the reefs in this area [6,7]. Management of the coastal waters sampling efforts and biweekly water grab samples. Keywords--land-based sources of pollution; inlets; coral
Metal precipitation at grain boundaries in silicon: Dependence on grain boundary character are combined to determine the dependence of metal silicide precipitate formation on grain boundary character and microstructure in multicrystalline silicon mc-Si . Metal silicide precipitate decoration is observed to increase
Boundary conditions for the subdiffusion equation
Shkilev, V. P.
2013-04-15
The boundary conditions for the subdiffusion equations are formulated using the continuous-time random walk model, as well as several versions of the random walk model on an irregular lattice. It is shown that the boundary conditions for the same equation in different models have different forms, and this difference considerably affects the solutions of this equation.
2001 TRAFFIC ZONE BOUNDARIES Zone Numbers
Toronto, University of
2001 TRAFFIC ZONE BOUNDARIES Zone Numbers & Detailed Definitions #12;2001 TRAFFIC ZONE BOUNDARIES of Toronto Joint Program in Transportation January 2003 #12;PREFACE This report presents the 2001 traffic zone numbers by local municipalities in the 2001 TTS survey area. The second part presents detailed
Environmental boundaries to energy development
Trivelpiece, A.W.
1989-01-01
Public concern about the environment, health and safety consequences of energy technology has been growing steadily for more than two decades in the United States. This concern forms an important boundary condition as the United States seeks to develop a new National Energy Strategy. Furthermore, the international aspects of the energy/environment interface such as acid rain global climate change and stratospheric ozone depletion are very prominent in US thinking. In fact, the energy systems of the world are becoming more closely coupled environmentally and otherwise. Now where is this coupling more important than that between the industrialized and developing world; the choices made by each will have profound effects on the other. The development of energy technologies compatible with both economic growth and improving and sustaining environmental quality represents a major R D challenge to the US and USSR. Decision about adoption of new technology and R D priorities can be improved by better measurements of how energy sources and uses are changing throughout the world and better methods to project the potential consequences of these decisions. Such projection require understanding relative risks of alternating existing and evolving technologies. All of these R D areas, technology improvement energy system monitoring and projection and comparative risk assessment are the topics of this seminar. Progress in each may be enhanced by collaboration and cooperation between our two countries. 7 refs., 27 figs., 5 tabs.
New Boundaries for the B-Model
Bergman, Aaron
2008-01-01
Witten couples the open topological B-model to a holomorphic vector bundle by adding to the boundary of the worldsheet a Wilson loop for an integrable connection on the bundle. Using the descent procedure for boundary vertex operators in this context, I generalize this construction to write a worldsheet coupling for a graded vector bundle with an integrable superconnection. I then compute the open string vertex operators between two such boundaries. A theorem of J. Block gives that this is equivalent to coupling the B-model to an arbitrary object in the derived category.
National Weather Service Wichita, KS
) Flashlight and extra batteries, or ones that generate their own energy by shaking them Battery operated and extra batteries Maps Small First Aid Kit White Distress Flag Tire Repair kit Winter supplies
A FREE BOUNDARY PROBLEM ARISING FROM SEGREGATION ...
2013-06-18
In this work, we show how to obtain a free boundary problem as the limit of a fully non linear elliptic .... b) to find the solution for a optimal partition problem.
PRE-PRECIPITATION PHENOMENA AT GRAIN BOUNDARIES
Briceno-Valero, J.
2010-01-01
13820 DE82 0 1 2 7 9 4 PRE-PRECIPITATION PHENOMENA AT GRAINof any evidence suggesting precipitation has occurred. Theand grain boundary precipitation have shown (1) that there
Suppression of Grain Boundaries in Graphene Growth on Superstructured...
Office of Scientific and Technical Information (OSTI)
Suppression of Grain Boundaries in Graphene Growth on Superstructured Mn-Cu(111) Surface Prev Next Title: Suppression of Grain Boundaries in Graphene Growth on...
Heat content asymptotics with transmittal and transmission boundary conditions
Peter Gilkey; Klaus Kirsten
2002-06-14
We study the heat content asymptotics on a Riemannian manifold with smoooth boundary defined by Dirichlet, Neumann, transmittal and transmission boundary conditions.
Singular perturbation problem in boundary/fractional combustion
2015-08-18
reaction-diffusion equation, where the reaction term is of combustion type. ... Free boundary problem, combustion theory, boundary reaction- diffusion, fractional ...
EA-1973: Kootenai River Restoration at Bonners Ferry, Boundary...
73: Kootenai River Restoration at Bonners Ferry, Boundary County, Idaho EA-1973: Kootenai River Restoration at Bonners Ferry, Boundary County, Idaho Summary Bonneville Power...
Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Boundary Analysis of Biological Pathways to Hydrogen Production Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen Production Report documenting the biological and...
Behaviour of boundary functions for quantum billiards
A. Bäcker; S. Fürstberger; R. Schubert; F. Steiner
2002-10-16
We study the behaviour of the normal derivative of eigenfunctions of the Helmholtz equation inside billiards with Dirichlet boundary condition. These boundary functions are of particular importance because they uniquely determine the eigenfunctions inside the billiard and also other physical quantities of interest. Therefore they form a reduced representation of the quantum system, analogous to the Poincar\\'e section of the classical system. For the normal derivatives we introduce an equivalent to the standard Green function and derive an integral equation on the boundary. Based on this integral equation we compute the first two terms of the mean asymptotic behaviour of the boundary functions for large energies. The first term is universal and independent of the shape of the billiard. The second one is proportional to the curvature of the boundary. The asymptotic behaviour is compared with numerical results for the stadium billiard, different limacon billiards and the circle billiard, and good agreement is found. Furthermore we derive an asymptotic completeness relation for the boundary functions.
E ective boundary conditions for laminar ows over periodic rough boundaries
Achdou, Yves
E#27;ective boundary conditions for laminar #29;ows over periodic rough boundaries Yves Achdou #3 are proposed for a laminar #29;ow over a rough wall with periodic roughness elements. These e#27;ective is such an approach ? In this paper, we wish to answer these questions for laminar #29;ows over periodic rough walls
Barmak, Katayun [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 and Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Darbal, Amith [Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Ganesh, Kameswaran J.; Ferreira, Paulo J. [Materials Science and Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712 (United States); Rickman, Jeffrey M. [Department of Materials Science and Engineering and Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Sun, Tik; Yao, Bo; Warren, Andrew P.; Coffey, Kevin R., E-mail: kb2612@columbia.edu [Department of Materials Science and Engineering, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States)
2014-11-01
The relative contributions of various defects to the measured resistivity in nanocrystalline Cu were investigated, including a quantitative account of twin-boundary scattering. It has been difficult to quantitatively assess the impact twin boundary scattering has on the classical size effect of electrical resistivity, due to limitations in characterizing twin boundaries in nanocrystalline Cu. In this study, crystal orientation maps of nanocrystalline Cu films were obtained via precession-assisted electron diffraction in the transmission electron microscope. These orientation images were used to characterize grain boundaries and to measure the average grain size of a microstructure, with and without considering twin boundaries. The results of these studies indicate that the contribution from grain-boundary scattering is the dominant factor (as compared to surface scattering) leading to enhanced resistivity. The resistivity data can be well-described by the combined Fuchs–Sondheimer surface scattering model and Mayadas–Shatzkes grain-boundary scattering model using Matthiessen's rule with a surface specularity coefficient of p?=?0.48 and a grain-boundary reflection coefficient of R?=?0.26.
Wireless boundary monitor system and method
Haynes, Howard D. (Knoxville, TN); Ayers, Curtis W. (Kingston, TN)
1997-01-01
A wireless boundary monitor system used to monitor the integrity of a boundary surrounding an area uses at least two housings having at least one transmitting means for emitting ultrasonic pressure waves to a medium. Each of the housings has a plurality of receiving means for sensing the pressure waves in the medium. The transmitting means and the receiving means of each housing are aimable and communicably linked. At least one of the housings is equipped with a local alarm means for emitting a first alarm indication whereby, when the pressure waves propagating from a transmitting means to a receiving means are sufficiently blocked by an object a local alarm means or a remote alarm means or a combination thereof emit respective alarm indications. The system may be reset either manually or automatically. This wireless boundary monitor system has useful applications in both indoor and outdoor environments.
Wireless boundary monitor system and method
Haynes, H.D.; Ayers, C.W.
1997-12-09
A wireless boundary monitor system used to monitor the integrity of a boundary surrounding an area uses at least two housings having at least one transmitting means for emitting ultrasonic pressure waves to a medium. Each of the housings has a plurality of receiving means for sensing the pressure waves in the medium. The transmitting means and the receiving means of each housing are aimable and communicably linked. At least one of the housings is equipped with a local alarm means for emitting a first alarm indication whereby, when the pressure waves propagating from a transmitting means to a receiving means are sufficiently blocked by an object a local alarm means or a remote alarm means or a combination thereof emit respective alarm indications. The system may be reset either manually or automatically. This wireless boundary monitor system has useful applications in both indoor and outdoor environments. 4 figs.
Resonant transitions due to changing boundaries
F. Anzà; A. Messina; B. Militello
2015-01-10
The problem of a particle confined in a box with moving walls is studied, focusing on the case of small perturbations which do not alter the shape of the boundary (\\lq pantography\\rq). The presence of resonant transitions involving the natural transition frequencies of the system and the Fourier transform of the velocity of the walls of the box is brought to the light. The special case of a pantographic change of a circular box is analyzed in dept, also bringing to light the fact that the movement of the boundary cannot affect the angular momentum of the particle.
Planetary Boundary Layer from AERI and MPL
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Sawyer, Virginia
The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.
Planetary Boundary Layer from AERI and MPL
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Sawyer, Virginia
2014-02-13
The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.
Determining environmental boundaries: asynchronous communication and physical
Ferguson, Thomas S.
to cooperatively locate the boundary of a given environmental function in two space dimensions using a combi this substitution is successfully taking place are de-mining operations [7], military urban operations [20 [23], or energy-minimizing curve. This process simulates elastic material which can dynamically
Origin of morphotropic phase boundaries in ferroelectrics
Wu, Zhigang
, Peter Liermann3 & Zhigang Wu4 A piezoelectric material is one that generates a voltage in response to a mechanical strain (and vice versa). The most useful piezo- electric materials display a transition region boundary under pressure. The results are consistent with first- principles theoretical predictions3
Thick diffusion limit boundary layer test problems
Bailey, T. S.; Warsa, J. S.; Chang, J. H.; Adams, M. L.
2013-07-01
We develop two simple test problems that quantify the behavior of computational transport solutions in the presence of boundary layers that are not resolved by the spatial grid. In particular we study the quantitative effects of 'contamination' terms that, according to previous asymptotic analyses, may have a detrimental effect on the solutions obtained by both discontinuous finite element (DFEM) and characteristic-method (CM) spatial discretizations, at least for boundary layers caused by azimuthally asymmetric incident intensities. Few numerical results have illustrated the effects of this contamination, and none have quantified it to our knowledge. Our test problems use leading-order analytic solutions that should be equal to zero in the problem interior, which means the observed interior solution is the error introduced by the contamination terms. Results from DFEM solutions demonstrate that the contamination terms can cause error propagation into the problem interior for both orthogonal and non-orthogonal grids, and that this error is much worse for non-orthogonal grids. This behavior is consistent with the predictions of previous analyses. We conclude that these boundary layer test problems and their variants are useful tools for the study of errors that are introduced by unresolved boundary layers in diffusive transport problems. (authors)
The Importance of Carbon Footprint Estimation Boundaries
Kammen, Daniel M.
The Importance of Carbon Footprint Estimation Boundaries H . S C O T T M A T T H E W S , C H R I and organizations are pursuing "carbon footprint" projects to estimate their own contributions to global climate change. Protocol definitions from carbon registries help organizations analyze their footprints
Vortex rings impinging on permeable boundaries
Mujal-Colilles, Anna; Dalziel, Stuart B.; Bateman, Allen
2015-01-17
of the boundary layer inside 548 the porous media or the flux exchange between the downstream and upstream sides of the 549 grid. 550 Recalling that one of the main differences between our experiments and the thin grid 551 research already published...
Lateral boundary errors in regional numerical weather
?umer, Slobodan
Lateral boundary errors in regional numerical weather prediction models Author: Ana Car Advisor, they describe evolution of atmospher - weather forecast. Every NWP model solves the same system of equations (1: assoc. prof. dr. Nedjeljka Zagar January 5, 2015 Abstract Regional models are used in many national
Accuracy Requirements for Rural Land Parcel Boundaries
Stock, Kristin
Accuracy Requirements for Rural Land Parcel Boundaries Kristin M. Stock School of Planning accuracy of about +/-0.2m. Utilities companies and local authorities in rural areas have more relaxed of Planning, Landscape Architecture and Surveying at Queensland University of Technology, and the Geodetic
1. Integrated Database 2. Boundary Analysis
of research? Data storage needs Meta data: legacy information Data processing diagrams Pastures Ecological that change in response to these processes Key processes that act as "drivers" of the system Key ecosystem of physical, ecological, social, and political boundaries using geographic information system Hypothesis 2
Title: Ontario Greenbelt Boundary File Data Creator /
Title: Ontario Greenbelt Boundary File Data Creator / Copyright Owner: Ontario Ministry of Municipal Affairs and Housing Publisher: Ontario Ministry of Municipal Affairs and Housing Edition: N/A Versions: N/A Publication Date: N/A Coverage Date(s): N/A Updates: N/A Abstract: The Ontario Greenbelt
Differential-Equation Based Absorbing Boundary Conditions
Schneider, John B.
Chapter 6 Differential-Equation Based Absorbing Boundary Conditions 6.1 Introduction A simple in the analysis of a wide range of FDTD-related topics. 6.2 The Advection Equation The wave equation that governs.2) The second form represents the equation in terms of an operator operating on Ez where the operator
Distributed Boundary Estimation using Sensor Networks
Ramamritham, Krithi
where such boundaries need to be detected include monitoring the spread of toxic gases [1], oil spills in oceans [2], or even tracking storm cloud front. Oil companies are interested in deploying off-shore sensor networks to monitor the area where oil spills normally happen. The focus in these cases
TRACKING DYNAMIC BOUNDARIES BY EVOLVING Tingting Jiang
Tingting Jiang
TRACKING DYNAMIC BOUNDARIES BY EVOLVING CURVES by Tingting Jiang Department of Computer Science Duke University Date: Approved: Carlo Tomasi, Supervisor Ron Parr Scott C. Schmidler Xiaobai Sun in the Department of Computer Science in the Graduate School of Duke University 2007 #12;ABSTRACT TRACKING DYNAMIC
Elementary Differential Equations with Boundary Value Problems
William F. Trench
2014-02-24
Dec 1, 2013 ... For more information, please contact jcostanz@trinity.edu. ..... (Laplace's Equation), the functions defining the boundary conditions on a given side of the rectangular .... change in heat of the object as its temperature changes from T0 to T is a(T ...... Let y be the angle measured from the rest position (vertically ...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Uberuaga, Blas Pedro; Vernon, Louis J.; Martinez, Enrique; Voter, Arthur F.
2015-03-13
Nanocrystalline materials have received great attention due to their potential for improved functionality and have been proposed for extreme environments where the interfaces are expected to promote radiation tolerance. However, the precise role of the interfaces in modifying defect behavior is unclear. Using long-time simulations methods, we determine the mobility of defects and defect clusters at grain boundaries in Cu. We find that mobilities vary significantly with boundary structure and cluster size, with larger clusters exhibiting reduced mobility, and that interface sink efficiency depends on the kinetics of defects within the interface via the in-boundary annihilation rate of defects. Thus,more »sink efficiency is a strong function of defect mobility, which depends on boundary structure, a property that evolves with time. Further, defect mobility at boundaries can be slower than in the bulk, which has general implications for the properties of polycrystalline materials. Finally, we correlate defect energetics with the volumes of atomic sites at the boundary.« less
Boundary Plasma Turbulence Simulations for Tokamaks
Xu, X; Umansky, M; Dudson, B; Snyder, P
2008-05-15
The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.
Open Boundary Conditions for Dissipative MHD
Meier, E T
2011-11-10
In modeling magnetic confinement, astrophysics, and plasma propulsion, representing the entire physical domain is often difficult or impossible, and artificial, or 'open' boundaries are appropriate. A novel open boundary condition (BC) for dissipative MHD, called Lacuna-based open BC (LOBC), is presented. LOBC, based on the idea of lacuna-based truncation originally presented by V.S. Ryaben'kii and S.V. Tsynkov, provide truncation with low numerical noise and minimal reflections. For hyperbolic systems, characteristic-based BC (CBC) exist for separating the solution into outgoing and incoming parts. In the hyperbolic-parabolic dissipative MHD system, such separation is not possible, and CBC are numerically unstable. LOBC are applied in dissipative MHD test problems including a translating FRC, and coaxial-electrode plasma acceleration. Solution quality is compared to solutions using CBC and zero-normal derivative BC. LOBC are a promising new open BC option for dissipative MHD.
Proteoglycan 4 metabolism and boundary lubrication of articular cartilage
Schmidt, Tannin A.
2006-01-01
ability to act as boundary lubricants. Ann Rheum Dis 43:641-load-bearing boundary lubricant in the joint. Br J Rheumatolof the cartilage and lubricant. Arthritis Rheum 11:674-82,
Crystallographically consistent percolation theory for grain boundary networks
Frary, Megan
2005-01-01
Grain boundaries are known to play a role in many important material properties including creep resistance, ductility and cracking resistance. Although the structure and properties of individual boundaries are important, ...
Cylinder kernel expansion of Casimir energy with a Robin boundary
Liu, Zhonghai
2006-10-30
We compute the Casimir energy of a massless scalar field obeying the Robin boundary condition on one plate and the Dirichlet boundary condition on another plate for two parallel plates with a separation of alpha. The ...
Thermodynamic stability and implications of anisotropic boundary particles
Siem, Ellen J. (Ellen Jane), 1979-
2005-01-01
(cont.) Generally, a boundary is nonplanar in the neighborhood of an attached particle--even when anisotropic interfacial free energies do not produce faceting-and maintains a icKy = 0 while the boundary particles maintain ...
Ising Interfaces and Free Boundary Conditions
Clément Hongler; Kalle Kytölä
2011-10-17
We study the interfaces arising in the two-dimensional Ising model at critical temperature, without magnetic field. We show that in the presence of free boundary conditions between plus and minus spins, the scaling limit of these interfaces can be described by a variant of SLE, called dipolar SLE(3). This generalizes a celebrated result of Chelkak and Smirnov and proves a conjecture of Bauer, Bernard and Houdayer. We mention two possible applications of our result.
Laminar boundary layers in convective heat transport
Christian Seis
2012-12-12
We study Rayleigh-Benard convection in the high-Rayleigh-number and high-Prandtl-number regime, i.e., we consider a fluid in a container that is exposed to strong heating of the bottom and cooling of the top plate in the absence of inertia effects. While the dynamics in the bulk are characterized by a chaotic convective heat flow, the boundary layers at the horizontal container plates are essentially conducting and thus the fluid is motionless. Consequently, the average temperature exhibits a linear profile in the boundary layers. In this article, we rigorously investigate the average temperature and oscillations in the boundary layer via local bounds on the temperature field. Moreover, we deduce that the temperature profile is indeed essentially linear close to the horizontal container plates. Our results are uniform in the system parameters (e.g. the Rayleigh number) up to logarithmic correction terms. An important tool in our analysis is a new Hardy-type estimate for the convecting velocity field, which can be used to control the fluid motion in the layer. The bounds on the temperature field are derived with the help of local maximal regularity estimates for convection-diffusion equations.
Laminar boundary layers in convective heat transport
Seis, Christian
2012-01-01
We study Rayleigh-Benard convection in the high-Rayleigh-number and high-Prandtl-number regime, i.e., we consider a fluid in a container that is exposed to strong heating of the bottom and cooling of the top plate in the absence of inertia effects. While the dynamics in the bulk are characterized by a chaotic convective heat flow, the boundary layers at the horizontal container plates are essentially conducting and thus the fluid is motionless. Consequently, the average temperature exhibits a linear profile in the boundary layers. In this article, we rigorously investigate the average temperature and oscillations in the boundary layer via local bounds on the temperature field. Moreover, we deduce that the temperature profile is indeed essentially linear close to the horizontal container plates. Our results are uniform in the system parameters (e.g. the Rayleigh number) up to logarithmic correction terms. An important tool in our analysis is a new Hardy-type estimate for the convecting velocity field, which ca...
Mesoscale coupled ocean-atmosphere feedbacks in boundary current systems
Putrasahan, Dian Ariyani
2012-01-01
productive oceanic eastern boundary current, providing anCurrent System and the Kuroshio Extension uses OFES products for their oceanic
Defining window-boundaries for genomic analyses using smoothing...
Office of Scientific and Technical Information (OSTI)
undesirable window boundary specifications, or highly correlated test statistics. We introduce a method for defining windows based on statistically guided...
Correct traction boundary conditions in the indeterminate couple stress model
Patrizio Neff; Ionel-Dumitrel Ghiba; Angela Madeo; Ingo Münch
2015-04-02
In this paper we consider the Grioli-Koiter-Mindlin-Toupin indeterminatecouple stress model. The main aim is to show that the traction boundary conditions were not yet completely deduced. As it turns out, and to our own surprise, restricting the boundary condition framework from the strain gradient models to the couple stress model does not reduce to Mindlin's set of accepted boundary conditions. We present therefore, for the first time the complete, consistent set of traction boundary conditions.
Effects of Boundary Conditions on Single-File Pedestrian Flow
Zhang, Jun; Seyfried, Armin
2015-01-01
In this paper we investigate effects of boundary conditions on one dimensional pedestrian flow which involves purely longitudinal interactions. Qualitatively, stop-and-go waves are observed under closed boundary condition and dissolve when the boundary is open. To get more detailed information the fundamental diagrams of the open and closed systems are compared using Voronoi-based measurement method. Higher maximal specific flow is observed from the pedestrian movement at open boundary condition.
Nonuniqeness in a free boundary problem from combustion
2014-10-31
Nonuniqeness in a free boundary problem from combustion. Arshak Petrosyan joint with Aaron Yip. Department of Mathematics. Purdue University.
Fusion for AdS/CFT boundary S-matrices
Rafael I. Nepomechie; Rodrigo A. Pimenta
2015-09-14
We propose a fusion formula for AdS/CFT worldsheet boundary S-matrices. We show that, starting from the fundamental Y=0 boundary S-matrix, this formula correctly reproduces the two-particle bound-state boundary S-matrices.
Testing outer boundary treatments for the Einstein equations
Oliver Rinne; Lee Lindblom; Mark A. Scheel
2007-07-25
Various methods of treating outer boundaries in numerical relativity are compared using a simple test problem: a Schwarzschild black hole with an outgoing gravitational wave perturbation. Numerical solutions computed using different boundary treatments are compared to a `reference' numerical solution obtained by placing the outer boundary at a very large radius. For each boundary treatment, the full solutions including constraint violations and extracted gravitational waves are compared to those of the reference solution, thereby assessing the reflections caused by the artificial boundary. These tests use a first-order generalized harmonic formulation of the Einstein equations. Constraint-preserving boundary conditions for this system are reviewed, and an improved boundary condition on the gauge degrees of freedom is presented. Alternate boundary conditions evaluated here include freezing the incoming characteristic fields, Sommerfeld boundary conditions, and the constraint-preserving boundary conditions of Kreiss and Winicour. Rather different approaches to boundary treatments, such as sponge layers and spatial compactification, are also tested. Overall the best treatment found here combines boundary conditions that preserve the constraints, freeze the Newman-Penrose scalar Psi_0, and control gauge reflections.
Harmonic Initial-Boundary Evolution in General Relativity
Maria C. Babiuc; Bela Szilagyi; Jeffrey Winicour
2006-03-14
Computational techniques which establish the stability of an evolution-boundary algorithm for a model wave equation with shift are incorporated into a well-posed version of the initial-boundary value problem for gravitational theory in harmonic coordinates. The resulting algorithm is implemented as a 3-dimensional numerical code which we demonstrate to provide stable, convergent Cauchy evolution in gauge wave and shifted gauge wave testbeds. Code performance is compared for Dirichlet, Neumann and Sommerfeld boundary conditions and for boundary conditions which explicitly incorporate constraint preservation. The results are used to assess strategies for obtaining physically realistic boundary data by means of Cauchy-characteristic matching.
Grain boundary characterization in an X750 alloy
Kevin Fisher; Sebastien Teysseyre; Emmanuelle Marquis
2012-11-01
Grain boundary chemistry in an X750 Ni alloy was analyzed by atom probe tomography in an effort to clarify the possible roles of elemental segregation and carbide presence on the stress corrosion cracking behavior of Ni alloys. Two types of cracks are observed: straight cracks along twin boundaries and wavy cracks at general boundaries. It was found that carbides (M23C6 and TiC) are present at both twin and general boundaries, with comparable B and P segregation for all types of grain boundaries. Twin boundaries intercept ?’ precipitates while the general boundaries wave around the ?’ and carbide precipitates. Near a crack tip, oxidation takes place on the periphery of carbide precipitate.
Microfluidics: The no-slip boundary condition
Eric Lauga; Michael P. Brenner; Howard A. Stone
2005-09-28
The no-slip boundary condition at a solid-liquid interface is at the center of our understanding of fluid mechanics. However, this condition is an assumption that cannot be derived from first principles and could, in theory, be violated. We present a review of recent experimental, numerical and theoretical investigations on the subject. The physical picture that emerges is that of a complex behavior at a liquid/solid interface, involving an interplay of many physico-chemical parameters, including wetting, shear rate, pressure, surface charge, surface roughness, impurities and dissolved gas.
A study on boundary separation in an idealized ocean model
Düben, Peter D
2015-01-01
In numerical ocean models coast lines change the direction from one grid cell to its neighbor and the value for viscosity is set to be as small as possible. Therefore, model simulations are not converged with resolution and boundary separation points differ in essential properties from flow separation in continuous flow fields. In this paper, we investigate the quality of the representation of boundary separation points in global ocean models. To this end, we apply well established criteria for boundary separation within an idealized ocean model setup. We investigate an eddy-resolving as well as a steady test case with idealized and unstructured coast lines in a shallow water model that is based on a finite element discretization method. The results show that well established criteria for separation fail to detect boundary separation points due to an insufficient representation of ocean flows along free-slip boundaries. Along no-slip boundaries, most separation criteria provide adequate results. However, a ve...
First order gravity: Actions, topological terms and boundaries
Corichi, Alejandro; Vukasinac, Tatjana
2013-01-01
We consider first order gravity in four dimensions. This means that the fundamental variables are a tetrad $e$ and a SO(3,1) connection $\\omega$. We study the most general action principle compatible with diffeomorphism invariance. This implies, in particular, considering besides the standard Einstein-Hilbert term, other terms that either do not change the equations of motion, or are topological in nature. Having a well defined action principle also implies adding additional boundary terms, whose detailed form may depend on the particular boundary conditions at hand. We consider spacetimes that include a boundary at infinity, satisfying asymptotically flat boundary conditions and/or an internal boundary satisfying isolated horizons boundary conditions. For our analysis we employ the covariant Hamiltonian formalism where the phase space $\\Gamma$ is given by solutions to the equation of motion. For each of the possible terms contributing to the action we study the well posedness of the action, its finiteness, t...
Effective Hydrodynamic Boundary Conditions for Corrugated Surfaces
Mongruel, Anne; Asmolov, Evgeny S; Vinogradova, Olga I
2012-01-01
We report measurements of the hydrodynamic drag force acting on a smooth sphere falling down under gravity to a plane decorated with microscopic periodic grooves. Both surfaces are lyophilic, so that a liquid (silicone oil) invades the surface texture being in the Wenzel state. A significant decrease in the hydrodynamic resistance force as compared with that predicted for two smooth surfaces is observed. To quantify the effect of roughness we use the effective no-slip boundary condition, which is applied at the imaginary smooth homogeneous isotropic surface located at an intermediate position between top and bottom of grooves. Such an effective condition fully characterizes the force reduction measured with the real surface, and the location of this effective plane is related to geometric parameters of the texture by a simple analytical formula.
Evaluation of wall boundary condition parameters for gas-solids...
Office of Scientific and Technical Information (OSTI)
predictions of various gas-solids fluidized beds. Several models for the granular flow wall boundary condition are available in the open literature for numerical modeling of...
A major lithospheric boundary in eastern California defined by...
ratios of Miocene-Recent basalts in eastern California, when screened for crustal contamination, vary dramatically and indicate the presence of a major lithospheric boundary that...
[Perovskite and Fluorite Grain Boundary Properties]. Final Project Report
Browning, N. D.
2004-02-24
One of the main areas of research in the last two years in this program has been the properties of grain boundaries in perovskite and fluorite structure materials.
Short wavelength topography on the inner-core boundary
Cao, A.; Masson, Y.; Romanowicz, B.
2006-01-01
Short wavelength topography on the inner-core boundary Aimin94720 Constraining the topography of the inner-core boundaryindicates the presence of topography at the inner- core
OPTIMAL REGULARITY AND THE FREE BOUNDARY IN THE ...
2013-06-25
nomenon of osmosis and osmotic pressure in biochemistry), and the problems on the temperature control on the boundary in thermics. We refer to the book of.
An outflow boundary condition and algorithm for incompressible two ...
S. Dong
2014-03-05
Feb 22, 2014 ... conditions for the phase field function on each boundary, which ...... These velocity histories indicate that the oil–water two-phase flow has ...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be...
Friction of Steel Sliding Under Boundary Lubrication Regime in...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
how to increase engine efficiency by reducing parasitic boundary regime friction losses and enable operation with lower viscosity oils while maintaining engine durability....
Sandia Energy - Elucidating the Role of Twin Boundaries in Deformation...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Impact Coupled experiment and modeling reveal the dramatic and complex impact of high-density twin boundaries on microstructure evolution and deformation mechanisms Research...
T-duality trivializes bulk-boundary correspondence
Varghese Mathai; Guo Chuan Thiang
2015-07-26
Recently we introduced T-duality in the study of topological insulators. In this paper, we study the bulk-boundary correspondence for three phenomena in condensed matter physics, namely, the quantum Hall effect, the Chern insulator, and time reversal invariant topological insulators. In all of these cases, we show that T-duality trivializes the bulk-boundary correspondence.
Boundary lubrication under water Wuge H. Briscoe1
Klein, Jacob
LETTERS Boundary lubrication under water Wuge H. Briscoe1 , Simon Titmuss1 , Fredrik Tiberg1 {, Robert K. Thomas1 , Duncan J. McGillivray1 { & Jacob Klein1,2 Boundary lubrication, in which the rubbing. This process, wide- spread in engineering applications, is also predicted to occur in biological lubrication
Modal Analysis of Homogeneous Optical Waveguides by Boundary Integral Method
Modal Analysis of Homogeneous Optical Waveguides by Boundary Integral Method Lei Wang J. Allen Cox of the waveguide. Two dierent systems of boundary integral equations are derived for the numerical solutions of the discrete propagation constants; one of them is in the form of Fredholm integral equations of the second
ANNIVERSARY REVIEW Grain boundary energy anisotropy: a review
Rohrer, Gregory S.
energy (B) gained when the two surfaces are brought together and new bonds are formed. The grain boundary with the stiffness of the material. The excess energy of the grANNIVERSARY REVIEW Grain boundary energy anisotropy: a review Gregory S. Rohrer Received: 29 April
Stability of High-Speed, Three-Dimensional Boundary Layers
Craig, Stuart A
2015-04-02
Boundary-layer experiments are performed in the low-disturbance, Mach 6 Quiet Tunnel (M6QT) at Texas A&M University. The experiments are focused specifically on investigating the physics of two three-dimensional phenomena in hypersonic boundary...
LARGE EDDY SIMULATION OF TURBULENT BOUNDARY LAYERS OVER ROUGH BEDS
Pawlak, Geno
that determines the response of the boundary layer is not clear. One method to characterize the irregular nature with different spectral slopes using 2D 10 % loading square waves as basis functions. These square waves can) is then used to simulate the turbulent boundary layer over the rough beds. The LES solver is first validated
Aero-Optical Effects of Supersonic Boundary Layers Stanislav Gordeyev
Gordeyev, Stanislav
Aero-Optical Effects of Supersonic Boundary Layers Stanislav Gordeyev and Eric Jumper University, Colorado 80840 DOI: 10.2514/1.J051266 Aero-optical measurements of a zero-pressure-gradient, supersonic to describe aero-optical effects of both the subsonic and the supersonic boundary layers. Finally, this new
Detecting Subject Boundaries Within Text: A Language Independent Statistical Approach
Edinburgh, University of
Detecting Subject Boundaries Within Text: A Language Independent Statistical Approach Korin describe here an algorithm for detect ing subject boundaries within text based on a statistical lexical assumptions is that a change in subject is accompanied by a change in vo cabulary. Using this assumption
SUPERSONIC SHEAR INSTABILITIES IN ASTROPHYSICAL BOUNDARY LAYERS
Belyaev, Mikhail A.; Rafikov, Roman R., E-mail: rrr@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Ivy Lane, Princeton, NJ 08540 (United States)
2012-06-20
Disk accretion onto weakly magnetized astrophysical objects often proceeds via a boundary layer (BL) that forms near the object's surface, in which the rotation speed of the accreted gas changes rapidly. Here, we study the initial stages of formation for such a BL around a white dwarf or a young star by examining the hydrodynamical shear instabilities that may initiate mixing and momentum transport between the two fluids of different densities moving supersonically with respect to each other. We find that an initially laminar BL is unstable to two different kinds of instabilities. One is an instability of a supersonic vortex sheet (implying a discontinuous initial profile of the angular speed of the gas) in the presence of gravity, which we find to have a growth rate of order (but less than) the orbital frequency. The other is a sonic instability of a finite width, supersonic shear layer, which is similar to the Papaloizou-Pringle instability. It has a growth rate proportional to the shear inside the transition layer, which is of order the orbital frequency times the ratio of stellar radius to the BL thickness. For a BL that is thin compared to the radius of the star, the shear rate is much larger than the orbital frequency. Thus, we conclude that sonic instabilities play a dominant role in the initial stages of nonmagnetic BL formation and give rise to very fast mixing between disk gas and stellar fluid in the supersonic regime.
Irradiation Assisted Grain Boundary Segregation in Steels
Lu, Zheng; Faulkner, Roy G.
2008-07-01
The understanding of radiation-induced grain boundary segregation (RIS) has considerably improved over the past decade. New models have been introduced and much effort has been devoted to obtaining comprehensive information on segregation from the literature. Analytical techniques have also improved so that chemical analysis of layers 1 nm thick is almost routine. This invited paper will review the major methods used currently for RIS prediction: namely, Rate Theory, Inverse Kirkendall, and Solute Drag approaches. A summary is made of the available data on phosphorus RIS in reactor pressure vessel (RPV) steels. This will be discussed in the light of the predictions of the various models in an effort to show which models are the most reliable and easy to use for forecasting P segregation behaviour in steels. A consequence of RIS in RPV steels is a radiation induced shift in the ductile to brittle transition temperature (DBTT). It will be shown how it is possible to relate radiation-induced P segregation levels to DBTT shift. Examples of this exercise will be given for RPV steels and for ferritic steels being considered for first wall fusion applications. Cr RIS in high alloy stainless steels and associated irradiation-assisted stress corrosion cracking (IASCC) will be briefly discussed. (authors)
Adena Rissman Assistant Professor, Human Dimensions of Ecosystem Management
Sheridan, Jennifer
Assistant, Just Food, New York City, NY. 1998 Organic Farming Summer Intern, Bellews Creek Farm, Hillsboro
Bazalii, B V; Degtyarev, S P
2013-07-31
An elliptic boundary-value problem for second-order equations with nonnegative characteristic form is investigated in the situation when there is a weak degeneracy on the boundary of the domain. A priori estimates are obtained for solutions and the problem is proved to be solvable in some weighted Hölder spaces. Bibliography: 18 titles.
Rohrer, Gregory S.
The Relationship Between Grain Boundary Energy, Grain Boundary Complexion Transitions, and Grain complexions. One idea is that complexion transitions occur to lower the average energy of the interface energy. Experiments on doped aluminas have shown that a complexion transition can change the relative
Science at the interface : grain boundaries in nanocrystalline metals.
Rodriguez, Mark Andrew; Follstaedt, David Martin; Knapp, James Arthur; Brewer, Luke N.; Holm, Elizabeth Ann; Foiles, Stephen Martin; Hattar, Khalid M.; Clark, Blythe B.; Olmsted, David L.; Medlin, Douglas L.
2009-09-01
Interfaces are a critical determinant of the full range of materials properties, especially at the nanoscale. Computational and experimental methods developed a comprehensive understanding of nanograin evolution based on a fundamental understanding of internal interfaces in nanocrystalline nickel. It has recently been shown that nanocrystals with a bi-modal grain-size distribution possess a unique combination of high-strength, ductility and wear-resistance. We performed a combined experimental and theoretical investigation of the structure and motion of internal interfaces in nanograined metal and the resulting grain evolution. The properties of grain boundaries are computed for an unprecedented range of boundaries. The presence of roughening transitions in grain boundaries is explored and related to dramatic changes in boundary mobility. Experimental observations show that abnormal grain growth in nanograined materials is unlike conventional scale material in both the level of defects and the formation of unfavored phases. Molecular dynamics simulations address the origins of some of these phenomena.
Grain Boundary (GB) Studies in Nano- and Micro- Crystalline Materials
Tanju, Mst Sohanazaman
2011-01-01
boundaries in silicon? Materials research society, Vol.122,bicrystal? Journal of Materials Science, 40(2005)3137- 5.in ZnO? Journal of Materials Science, 40(2005)3067-3074. 6.
Examining A Hypersonic Turbulent Boundary Layer at Low Reynolds Number
Semper, Michael Thomas
2013-05-15
The purpose of the current study was to answer several questions related to hypersonic, low Reynolds number, turbulent boundary layers, of which available data related to turbulence quantities is scarce. To that end, a ...
Static electric field in one-dimensional insulators without boundaries
Chen, Kuang-Ting
In this brief report, we show that in a one-dimensional insulating system with periodic boundary conditions, the coefficient of the ? term in the effective theory is not only determined by the topological index ?i?[superscript ...
Performance of a boundary layer ingesting propulsion system
Plas, Angélique (Angélique Pascale)
2006-01-01
This thesis presents an assessment of the aerodynamic performance of an aircraft propulsion system, with embedded engines, in the presence of aircraft fuselage boundary layer ingestion (BLI). The emphasis is on defining ...
Reconfiguring Boundary Relations: Robotic Innovations in Pharmacy Work
Barrett, Michael
Robotics is a rapidly expanding area of digital innovation with important implications for organizational practice in multioccupational settings. This paper explores the influence of robotic innovations on the boundary ...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly...
Analysis of civil aircraft propulsors with boundary layer ingestion
Hall, David Kenneth
2015-01-01
This thesis describes (i) guidelines for propulsor sizing, and (ii) strategies for fan turbomachinery conceptual design, for a boundary layer ingesting (BLI) propulsion system for advanced civil transport aircraft. For the ...
Distributed Roughness Receptivity in a Flat Plate Boundary Layer
Kuester, Matthew Scott
2014-04-18
the incoming boundary layer. This dissertation describes an experiment specifically designed to study the shielding effect. Three roughness configurations, a deterministic distributed roughness patch, a slanted rectangle, and the combination of the two, were...
Mineral Deformation at Earth's Core-Mantle Boundary
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km...
Technology adaptation and boundary management in bona fide virtual groups.
Zhang, Huiyan
2006-04-12
and norms of media combination and media use. Group boundaries were preserved when the influence of outgroup members were constrained through media use, such as excluding them from team conference calls, filtering messages from external groups or members...
A distributed boundary detection algorithm for multi-robot systems
McLurkin, James
We describe a distributed boundary detection algorithm suitable for use on multi-robot systems with dynamic network topologies. We assume that each robot has access to its local network geometry, which is the combination ...
Uniformly Loaded Rectangular Thin Plates with Symmetrical Boundary Conditions
Milan Batista
2010-01-27
In the article the Fourier series analytical solutions of uniformly loaded rectangular thin plates with symmetrical boundary conditions are considered. For all the cases the numerical values are tabulated.
Fusion of conformal interfaces and bulk induced boundary RG flows
Anatoly Konechny
2015-09-25
We consider the basic radius changing conformal interface for a free compact boson. After investigating different theoretical aspects of this object we focus on the fusion of this interface with conformal boundary conditions. At fractions of the self-dual radius there exist exceptional D-branes. It was argued in [1] that changing the radius in the bulk induces a boundary RG flow. Following [2] we conjecture that fusing the basic radius changing interface (that changes the radius from a fraction of the self-dual radius) with the exceptional boundary conditions gives the boundary condition which is the end point of the RG flow considered in [1]. By studying the fusion singularities we recover RG logarithms and see, in particular instances, how they get resummed into power singularities. We discuss what quantities need to be calculated to gain full non-perturbative control over the fusion.
Quantum Brownian motion near a point-like reflecting boundary
V. A. De Lorenci; E. S. Moreira Jr.; M. M. Silva
2014-07-07
The Brownian motion of a test particle interacting with a quantum scalar field in the presence of a perfectly reflecting boundary is studied in (1 + 1)-dimensional flat spacetime. Particularly, the expressions for dispersions in velocity and position of the particle are explicitly derived and their behaviors examined. The results are similar to those corresponding to an electric charge interacting with a quantum electromagnetic field near a reflecting plane boundary, mainly regarding the divergent behavior of the dispersions at the origin (where the boundary is placed), and at the time interval corresponding to a round trip of a light pulse between the particle and the boundary. We close by addressing some effects of allowing the position of the particle to fluctuate.
Boundary Circles of Mixed Phase Space, Hamiltonian Systems
Or Alus; Shmuel Fishman; James D. Meiss
2014-10-28
The phase space of an area-preserving map typically contains infinitely many elliptic islands embedded in a chaotic sea. Orbits near the boundary of a chaotic region have been observed to stick for long times, strongly influencing their transport properties. The boundary is composed of invariant circles, called "Boundary circles." We investigate the distribution of rotation numbers of boundary circles for the Henon quadratic map and show that the probability of occurrence of small elements of their continued fraction expansions is larger than would be expected for a number chosen at random. However, large elements occur with probabilities distributed proportionally to the random case. These results have implications for models of transport in mixed phase space.
Atomic Scale Details of Defect-Boundary Interactions
Chen, Di
2014-12-18
The study is aimed to understand atomic scale details of defect-boundary interactions, which are critical to develop radiation tolerant fuel cladding materials for harsher neutron environments. By means of molecular dynamics simulations, we...
Casimir Energy due to a Semi-Infinite Plane Boundary
H. Ahmedov; I. H. Duru
2006-08-25
Following the derivation of the Green function for the massless scalar field satisfying the Dirichlet boundary condition on the Plane (x > 0, y = 0), we calculate the Casimir energy.
Interaction between surface and atmosphere in a convective boundary layer /
Garai, Anirban
2013-01-01
of cold fluid constitute most of the heat transport andevent cold air descends to the ground, heat transport fromcold air during sweep events. The convective boundary layer has a great influence on moisture transport,
Computation of Mixed Type Functional Differential Boundary Value Problems
Abell, Kate A.; Elmer, Christopher E.; Humphries, A. R.; Van Vleck, Erik
2005-09-05
We study boundary value differential-difference equations where the difference terms may contain both advances and delays. Special attention is paid to connecting orbits, in particular to the modeling of the tails after ...
Grain boundary relaxation strengthening of nanocrystalline Ni–W alloys
Rupert, Timothy J.
The hardening effect caused by the relaxation of nonequilibrium grain boundary structure has been explored in nanocrystalline Ni–W alloys. First, the kinetics of relaxation hardening are studied, showing that higher annealing ...
Eddy-mean flow interactions in western boundary current jets
Waterman, Stephanie N
2009-01-01
This thesis examines the nature of eddy-mean flow interactions in western boundary current jets and recirculation gyre dynamics from both theoretical and observational perspectives. It includes theoretical studies of ...
Fusion of conformal interfaces and bulk induced boundary RG flows
Konechny, Anatoly
2015-01-01
We consider the basic radius changing conformal interface for a free compact boson. After investigating different theoretical aspects of this object we focus on the fusion of this interface with conformal boundary conditions. At fractions of the self-dual radius there exist exceptional D-branes. It was argued in [1] that changing the radius in the bulk induces a boundary RG flow. Following [2] we conjecture that fusing the basic radius changing interface (that changes the radius from a fraction of the self-dual radius) with the exceptional boundary conditions gives the boundary condition which is the end point of the RG flow considered in [1]. By studying the fusion singularities we recover RG logarithms and see, in particular instances, how they get resummed into power singularities. We discuss what quantities need to be calculated to gain full non-perturbative control over the fusion.
Grain boundary and triple junction diffusion in nanocrystalline copper
Wegner, M. Leuthold, J.; Peterlechner, M.; Divinski, S. V.; Song, X.; Wilde, G.
2014-09-07
Grain boundary and triple junction diffusion in nanocrystalline Cu samples with grain sizes, ?d?, of ?35 and ?44?nm produced by spark plasma sintering were investigated by the radiotracer method using the {sup 63}Ni isotope. The measured diffusivities, D{sub eff}, are comparable with those determined previously for Ni grain boundary diffusion in well-annealed, high purity, coarse grained, polycrystalline copper, substantiating the absence of a grain size effect on the kinetic properties of grain boundaries in a nanocrystalline material at grain sizes d???35?nm. Simultaneously, the analysis predicts that if triple junction diffusion of Ni in Cu is enhanced with respect to the corresponding grain boundary diffusion rate, it is still less than 500?D{sub gb} within the temperature interval from 420?K to 470?K.
Numerical simulations of supercell interactions with thermal boundaries
Kay, Michael Paul
1999-01-01
to examine the effects of the interaction of simulated supercede thunderstorms with thermal boundaries on storm morphology and low-level rotation. This study differs from previous supercede modeling studies that use homogeneous initial conditions. A non...
Flavor twisted boundary conditions in the Breit frame
Jiang, F.-J.; Tiburzi, B. C.
2008-08-01
We use a generalization of chiral perturbation theory to account for the effects of flavor twisted boundary conditions in the Breit frame. The relevant framework for two light flavors is an SU(6|4) partially quenched theory, where the extra valence quarks differ only by their boundary conditions. Focusing on the pion electromagnetic form factor, finite volume corrections are calculated at next-to-leading order in the chiral expansion and are estimated to be small on current lattices.
Biofuel Boundaries: Estimating the Medium-Term Supply Potential of Domestic Biofuels
Jones, Andrew; O'Hare, Michael; Farrell, Alexander
2007-01-01
Biofuel Boundaries: Estimating the Medium-Term SupplyAugust 22, 2007 Biofuel Boundaries: Estimating the Medium-significant amount of liquid biofuel (equivalent to 30-100%
Secure Mediated Databases K.S. Candan
Candan, SelÃ§uk
@cs.umd.edu Abstract With the evolution of the information superhighway, there is now an immense amount of information of paranoia. The Principle of Paranoia. The DBMS must take all steps necessary in order to insure the user. However, with the evolution of the information superhighway, there is now an immense amount
Fish, L.; Rathbone, W.
1982-01-01
floodgate. The water backs up, the pressure increases, and sooner or later the river fincba way out: over the top: or spilling out at the sides, or seeping tHough the surrounding land, or by breaking the dam. In any case; the uncontrolled leaks..., "cutting a steer out of the herd. Is that one ear-marked for the days dinner?" "Eventually," said the scientist. "They do something odd with it first, also the killer whales are technically farmers more than herders. In that wide patch of seaweed behind...
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass map shines light on77 PAGE OF PAGESpersonal CERTIFIED MAIL Fuel3S FINAL
Category:Wichita, KS | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoopButte County,Camilla,Thermal Gradient Holes Jump to: navigation,Category
D. Gottschalk; A. McBride; B. D. Reddy; A. Javili; P. Wriggers; C. B. Hirschberger
2015-05-06
A detailed theoretical and numerical investigation of the infinitesimal single-crystal gradient plasticity and grain-boundary theory of Gurtin (2008) "A theory of grain boundaries that accounts automatically for grain misorientation and grain-boundary orientation". Journal of the Mechanics and Physics of Solids 56 (2), 640-662, is performed. The governing equations and flow laws are recast in variational form. The associated incremental problem is formulated in minimization form and provides the basis for the subsequent finite element formulation. Various choices of the kinematic measure used to characterize the ability of the grain boundary to impede the flow of dislocations are compared. An alternative measure is also suggested. A series of three-dimensional numerical examples serve to elucidate the theory.
Andrey Piatnitski; Volodymyr Rybalko
2010-06-03
The paper deals with homogenization problem for nonlinear elliptic and parabolic equations in a periodically perforated domain, a nonlinear Fourier boundary conditions being imposed on the perforation border. Under the assumptions that the studied differential equation satisfies monotonicity and 2-growth conditions and that the coefficient of the boundary operator is centered at each level set of unknown function, we show that the problem under consideration admits homogenization and derive the effective model.
Piatnitski, Andrey
2010-01-01
The paper deals with homogenization problem for nonlinear elliptic and parabolic equations in a periodically perforated domain, a nonlinear Fourier boundary conditions being imposed on the perforation border. Under the assumptions that the studied differential equation satisfies monotonicity and 2-growth conditions and that the coefficient of the boundary operator is centered at each level set of unknown function, we show that the problem under consideration admits homogenization and derive the effective model.
Garmestani, Hamid
Migration and reorientation of grain boundaries in Zn bicrystals during annealing in a high angles to the free surfaces are annealed in the field of 17 T. Boundaries migrate reorienting almost driven boundary migration. The absolute boundary mobility was measured to be about 2:5 Â 10À8 m4 /J s. Ó
Structure and Chemistry of Yttria-Stabilized Cubic-Zirconia Symmetric Tilt Grain Boundaries
Pennycook, Steve
Structure and Chemistry of Yttria-Stabilized Cubic-Zirconia Symmetric Tilt Grain Boundaries boundaries in yttria-stabilized cubic-zirconia, 5 (310) and near- 13 (510), are studied by Z [001] symmetric tilt grain boundaries in yttria-stabilized cubic-zirconia (YSZ). The grain boundaries
Effective velocity boundary condition at a mixed slip surface
Sbragaglia, M
2006-01-01
This paper studies the nature of the effective velocity boundary conditions for liquid flow over a plane boundary on which small free-slip islands are randomly distributed. It is found that, to lowest order in the area fraction $\\beta$ covered by free-slip regions with characteristic size $a$, a macroscopic Navier-type slip condition emerges with a slip length of the order of $a\\beta$. The study is motivated by recent experiments which suggest that gas nano-bubbles may form on solid walls and may be responsible for the appearance of a partial slip boundary conditions for liquid flow. The results are also relevant for ultra-hydrophobic surfaces exploiting the so-called ``lotus effect''.
Explicit Expressions for 3D Boundary Integrals in Potential Theory
Nintcheu Fata, Sylvain
2009-01-01
On employing isoparametric, piecewise linear shape functions over a flat triangular domain, exact expressions are derived for all surface potentials involved in the numerical solution of three-dimensional singular and hyper-singular boundary integral equations of potential theory. These formulae, which are valid for an arbitrary source point in space, are represented as analytic expressions over the edges of the integration triangle. They can be used to solve integral equations defined on polygonal boundaries via the collocation method or may be utilized as analytic expressions for the inner integrals in the Galerkin technique. Also, the constant element approximation can be directly obtained with no extra effort. Sample problems solved by the collocation boundary element method for the Laplace equation are included to validate the proposed formulae.
Boundary-layer control by electric fields A feasibility study
Mendes, R V
1998-01-01
A problem of great concern in aviation and submarine propulsion is the control of the boundary layer and, in particular, the methods to extend the laminar region as a means to decrease noise and fuel consumption. In this paper we study the flow of air along an airfoil when a layer of ionized gas and a longitudinal electric field are created in the boundary layer region. By deriving scaling solutions and more accurate numerical solutions we discuss the possibility of achieving significant boundary layer control for realistic physical parameters. Practical design formulas and criteria are obtained. We also discuss the perspectives for active control of the laminar-to-turbulent transition fluctuations by electromagnetic field modulation.
Experimental studies of pedestrian flows under different boundary conditions
Zhang, Jun
2015-01-01
In this article the dynamics of pedestrian streams in four different scenarios are compared empirically to investigate the influence of boundary conditions on it. The Voronoi method, which allows high resolution and small fluctuations of measured density in time and space, is used to analyze the experiments. It is found that pedestrian movement in systems with different boundary conditions (open, periodic boundary conditions and outflow restrained) presents various characteristics especially when the density is larger than 2 m-2. In open corridor systems the specific flow increases continuously with increasing density till 4 m-2. The specific flow keeps constant in systems with restrained outflow, whereas it decreases from 1 (m.s)-1 to zero in system with closed periodical condition.
Wind on the boundary for the Abelian sandpile model
Philippe Ruelle
2007-07-25
We continue our investigation of the two-dimensional Abelian sandpile model in terms of a logarithmic conformal field theory with central charge c=-2, by introducing two new boundary conditions. These have two unusual features: they carry an intrinsic orientation, and, more strangely, they cannot be imposed uniformly on a whole boundary (like the edge of a cylinder). They lead to seven new boundary condition changing fields, some of them being in highest weight representations (weights -1/8, 0 and 3/8), some others belonging to indecomposable representations with rank 2 Jordan cells (lowest weights 0 and 1). Their fusion algebra appears to be in full agreement with the fusion rules conjectured by Gaberdiel and Kausch.
Edge Plasma Boundary Layer Generated By Kink Modes in Tokamaks
L.E. Zakharov
2010-11-22
This paper describes the structure of the electric current generated by external kink modes at the plasma edge using the ideally conducting plasma model. It is found that the edge current layer is created by both wall touching and free boundary kink modes. Near marginal stability, the total edge current has a universal expression as a result of partial compensation of the ?-functional surface current by the bulk current at the edge. The resolution of an apparent paradox with the pressure balance across the plasma boundary in the presence of the surface currents is provided.
Controlling Electromagnetic Fields at Boundaries of Arbitrary Geometries
Teo, Jonathon Yi Han; Molardi, Carlo; Genevet, Patrice
2015-01-01
Rapid developments in the emerging field of stretchable and conformable photonics necessitate analytical expressions for boundary conditions at metasurfaces of arbitrary geometries. Here, we introduce the concept of conformal boundary optics: a design theory that determines the optical response for designer input and output fields at such interfaces. Given any object, we can realise coatings to achieve exotic effects like optical illusions and anomalous diffraction behaviour. This approach is relevant to a broad range of applications from conventional refractive optics to the design of the next-generation of wearable optical components. This concept can be generalized to other fields of research where designer interfaces with nontrivial geometries are encountered.
Boundary conditions control for a Shallow-Water model
Kazantsev, Eugene
2012-01-01
A variational data assimilation technique was used to estimate optimal discretization of interpolation operators and derivatives in the nodes adjacent to the rigid boundary. Assimilation of artificially generated observational data in the shallow-water model in a square box and assimilation of real observations in the model of the Black sea are discussed. It is shown in both experiments that controlling the discretization of operators near a rigid boundary can bring the model solution closer to observations as in the assimilation window and beyond the window. This type of control allows also to improve climatic variability of the model.
Gradient zone boundary control in salt gradient solar ponds
Hull, John R. (Downers Grove, IL)
1984-01-01
A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.
Logarithmic CFT on the Boundary and the World-Sheet
Alex Lewis
2000-09-12
The correspondences between logarithmic operators in the CFTs on the boundary of AdS_3 and on the world-sheet and dipole fields in the bulk are studied using the free field formulation of the SL(2,C)/SU(2) WZNW model. We find that logarithmic operators on the boundary are related to operators on the world-sheet which are in indecomposable representations of SL(2). The Knizhnik-Zamolodchikov equation is used to determine the conditions for those representations to appear in the operator product expansions of the model.
Polymer Effects on Heat Transport in Laminar Boundary Layer Flow
Roberto Benzi; Emily S. C. Ching; Vivien W. S. Chu
2011-04-27
We consider a laminar Blasius boundary-layer flow above a slightly heated horizontal plate and study the effect of polymer additives on the heat transport. We show that the action of the polymers can be understood as a space-dependent effective viscosity that first increases from the zero-shear value then decreases exponentially back to the zero-shear value as one moves away from the boundary. We find that with such an effective viscosity, both the horizontal and vertical velocities near the plate are decreased thus leading to an increase in the friction drag and a decrease in the heat transport in the flow.
Humphreys, Eugene
, Transcontinental arch, and Yavapai Mazatzal province boundary), suggesting that older boundaries influenced
Static plane symmetric relativistic fluids and empty repelling singular boundaries
Ricardo E. Gamboa Saravi
2007-12-18
We present a detailed analysis of the general exact solution of Einstein's equation corresponding to a static and plane symmetric distribution of matter with density proportional to pressure. We study the geodesics in it and we show that this simple spacetime exhibits very curious properties. In particular, it has a free of matter repelling singular boundary and all geodesics bounce off it.
Higher-dimensional perfect fluids and empty singular boundaries
Ricardo E. Gamboa Saravi
2012-04-22
In order to find out whether empty singular boundaries can arise in higher dimensional Gravity, we study the solution of Einstein's equations consisting in a ($N+2$)-dimensional static and hyperplane symmetric perfect fluid satisfying the equation of state $\\rho=\\eta\\, p$, being $\\rho$ an arbitrary constant and $N\\geq2$. We show that this spacetime has some weird properties. In particular, in the case $\\eta>-1$, it has an empty (without matter) repulsive singular boundary. We also study the behavior of geodesics and the Cauchy problem for the propagation of massless scalar field in this spacetime. For $\\eta>1$, we find that only vertical null geodesics touch the boundary and bounce, and all of them start and finish at $z=\\infty$; whereas non-vertical null as well as all time-like ones are bounded between two planes determined by initial conditions. We obtain that the Cauchy problem for the propagation of a massless scalar field is well-posed and waves are completely reflected at the singularity, if we only demand the waves to have finite energy, although no boundary condition is required.
Modeling of dislocationgrain boundary interactions in FCC metals
Cai, Wei
- dynamics simulations (DD). The conceptual approach to be followed for single-crystal plasticity is straight using atomistic methods. For polycrystal plasticity, however, the prob- lem is significantly more complex due to the role of grain boundaries (GB) in plastic deformation. While the in- teractions between
Extending Boundaries with Meta-Design and Cultures of Participation
Fischer, Gerhard
urban planning problems, (3) modeling the buildings of the world in 3D, and (4) using Smart Grids to support energy sustainability. These examples show how meta- design and cultures of participation of participation, systemic problems, boundaries, distances, motivation, control, socio-technical environments ACM
Measurements of grain boundary properties in nanocrystalline ceramics
Chiang, Y.M.; Smyth, I.P.; Terwilliger, C.D. (Massachusetts Inst. of Tech., Cambridge, MA (USA). Dept. of Materials Science and Engineering); Petuskey, W.T. (Arizona State Univ., Tempe, AZ (USA). Dept. of Chemistry); Eastman, J.A. (Argonne National Lab., IL (USA))
1990-11-01
The advent of nanocrystalline ceramics prepared by a variety of solution-chemical and vapor deposition methods offers a unique opportunity for the determination grain boundary properties by bulk'' thermodynamic methods. In this paper we discuss results from two types of measurements on model nanocrystalline ceramics. The first is a solution thermodynamic measurement of the activity of nanocrystalline SiC in polycarbosilane-derived silicon carbide fibers (Nicalon). Structural studies have shown that Nicalon consists of well-ordered cubic ({beta} or 3C polytype) SiC grains separated by a very thin grain boundary layer (<1 nm thick) containing the oxygen. The physical properties and chemical reactivity of these fibers are distinctly different from that of bulk silicon carbide. Direct measurement of the alloy composition and analysis of the microstructure has allowed the dissolution reaction to be identified and a lower limit for the SiC activity in the nanocrystalline form to be determined. A second method of measuring grain boundary properties we have investigated for nanocrystalline Si and TiO{sub 2} is high temperature calorimetry. In appropriate samples the grain boundary enthalpy can be measured through the heat evolved during grain growth. Preliminary results on nanocrystalline Si prepared by the recrystallization of amorphous evaporated films and on TiO{sub 2} condensed from the vapor phase are discussed. 29 refs., 3 figs., 1 tab.
PPRODO: Prediction of Protein Domain Boundaries Using Neural Networks
Lee, Jooyoung
PPRODO: Prediction of Protein Domain Boundaries Using Neural Networks Jaehyun Sim, Seung-Yeon Kim-BLAST. A 10-fold cross-validation technique is performed to obtain the parameters of neural networks using; neural network INTRODUCTION Domains are semi-independent 3-dimensional (3D) units in proteins, and often
Subjective surfaces: a geometric model for boundary completion
Sarti, Alessandro; Malladi, Ravi; Sethian, J.A.
2000-06-01
We present a geometric model and a computational method for segmentation of images with missing boundaries. In many situations, the human visual system fills in missing gaps in edges and boundaries, building and completing information that is not present. Boundary completion presents a considerable challenge in computer vision, since most algorithms attempt to exploit existing data. A large body of work concerns completion models, which postulate how to construct missing data; these models are often trained and specific to particular images. In this paper, we take the following, alternative perspective: we consider a reference point within an image as given, and then develop an algorithm which tries to build missing information on the basis of the given point of view and the available information as boundary data to the algorithm. Starting from this point of view, a surface is constructed. It is then evolved with the mean curvature flow in the metric induced by the image until a piecewise constant solution is reached. We test the computational model on modal completion, amodal completion, texture, photo and medical images. We extend the geometric model and the algorithm to 3D in order to extract shapes from low signal/noise ratio medical volumes. Results in 3D echocardiography and 3D fetal echography are presented.
A Navier boundary value problem for Willmore surfaces of revolution #
Grunau, Hans-Christoph
A Navier boundary value problem for Willmore surfaces of revolution # Klaus Deckelnick + and Hans Forschungsgemeinschaft (DFG) is gratefully acknowledged + eÂmail: Klaus.Deckelnick@ovgu.de # eÂmail: Hans of closed Willmore surfaces of prescribed genus was proved by Simon [Sn] and Bauer & Kuwert [BK]. Con
Boundary value problems for the onedimensional Willmore equation
Grunau, Hans-Christoph
Boundary value problems for the oneÂdimensional Willmore equation Klaus Deckelnick # and Hans--known that the corresponding surface # has to satisfy the Willmore equation #H + 2H(H 2 -K) = 0 on #, (1) # eÂmail: Klaus Willmore surfaces of prescribed genus has been proved by Simon [Sn] and Bauer & Kuwert [BK]. Also, local
Boundary value problems for the one-dimensional Willmore equation
Grunau, Hans-Christoph
Boundary value problems for the one-dimensional Willmore equation Klaus Deckelnick and HansÂknown that the corresponding surface has to satisfy the Willmore equation H + 2H(H2 - K) = 0 on , (1) e-mail: Klaus Willmore surfaces of prescribed genus has been proved by Simon [Sn] and Bauer & Kuwert [BK]. Also, local
NASA/TM2014218280 Analysis of Well-Clear Boundary
Muñoz, César A.
NASA/TM2014218280 Analysis of Well-Clear Boundary Models for the Integration of UAS in the NAS Research Center, Hampton, Virginia June 2014 #12;NASA STI Program . . . in Profile Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA scientific
Zoning boundaries can make good neighbors in conservation
Zoning boundaries can make good neighbors in conservation A panda with a GPS collar in the Wolong changes might be needed." A unique case study that does of one of the world's renowned nature reserves giant panda census, geographic data on locations of roads and human establishments, and new data
well posedness of Hyperbolic Initial Boundary Value Problems
MÃ©tivier, Guy
direction, we show on an example that, even for symmetric systems in the sense of Friedrichs, with variable and the class M . . . . . . . . . . . . . . . . . 11 2.3 The incoming bundle, block decomposition and if the boundary condition is maximal 2 #12;strictly dissipative , then for all T 0, u0 L2(Rd), f L1([0, T]; L2
Meta-Design: Expanding Boundaries and Redistributing Control in Design
Fischer, Gerhard
Meta-Design: Expanding Boundaries and Redistributing Control in Design Gerhard Fischer Center for Lifelong Learning and Design University of Colorado, Boulder http://l3d.cs.colorado.edu/~gerhard/ Abstract. Meta-design is an emerging conceptual framework aimed at defining and creating socio
UNCORRECTED 2 Multiscale boundary conditions in crystalline solids
Qian, Dong
UNCORRECTED PROOF 1 2 Multiscale boundary conditions in crystalline solids: 3 Theory scale simulations of crystalline solids. Based on Fourier analysis of regular lattices structures with a crystalline gold substrate. Complete atomistic resolution on the coarse grain is alternatively 19 employed
Radiating Instability of a Meridional Boundary Current HRISTINA G. HRISTOVA
energy away from the source of instability. It can be contrasted with a trapped instability ocean basins. Un- stable boundary currents can be an important source of eddy kinetic energy. Radiating instabilities propagate energy away from the locally unstable region by coupling to the free
Two-Baryon Systems with Twisted Boundary Conditions
Zohreh Davoudi
2014-11-07
I derive the most general quantization condition for energy eigenvalues of two interacting baryons in a finite cubic volume when arbitrary twisted boundary conditions are imposed on their finite-volume wavefunctions. These quantization conditions are used, along with experimentally known scattering parameters of two-nucleon systems in the coupled 3S1-3D1 channels, to demonstrate the expected effect of a selection of twisted boundary conditions on the spectrum of the deuteron. It is shown that an order of magnitude reduction in the finite-volume corrections to the deuteron binding energy arise in moderate volumes with a proper choice of boundary conditions on the proton and the neutron, or by averaging the result of periodic and anti-periodic boundary conditions. These observations mean that a sub-percent accuracy can be achieved in the determination of the deuteron binding energy at (spatial) volumes as small as ~(9[fm])^3 in upcoming lattice QCD calculations of this nucleus with physical light-quark masses. The results reviewed in this talk are presented in details in Ref. [1].
Boundary Integral Methods for Multicomponent Fluids and Multiphase Materials
. An important and complicating property of such systems is surface tension (or surface energy in the materials of Mathematical Sciences, New York University, New York, NY 10012. 1 #12;governing the bulk fluid or materialBoundary Integral Methods for Multicomponent Fluids and Multiphase Materials T.Y. Hou J
Stratified Flow over Topography: Wave Generation and Boundary Layer Separation
Sutherland, Bruce
Stratified Flow over Topography: Wave Generation and Boundary Layer Separation B. R. Sutherland topography. We have chosen to use periodic, finiteamplitude hills which are representative of the Earth upon internal waves generated by flow over rough topography. 1 Introduction Internal waves propagate
Stratified Flow over Topography: Wave Generation and Boundary Layer Separation
Sutherland, Bruce
Stratified Flow over Topography: Wave Generation and Boundary Layer Separation B. R. Sutherland Abstract We have performed laboratory experiments to study wave generation over and in the lee of model upon internal waves generated by flow over rough topography. 1 Introduction Internal waves propagate
Carbon transport in the bottom boundary layer. Final report
Agrawal, Y.C.
1998-10-05
This report summarizes the activities and findings from a field experiment devised to estimate the rates and mechanisms of transport of carbon across the continental shelves. The specific site chosen for the experiment was the mid-Atlantic Bight, a region off the North Carolina coast. The experiment involved a large contingent of scientists from many institutions. The specific component of the program was the transport of carbon in the bottom boundary layer. The postulate mechanisms of transport of carbon in the bottom boundary layer are: resuspension and advection, downward deposition, and accumulation. The high turbulence levels in the bottom boundary layer require the understanding of the coupling between turbulence and bottom sediments. The specific issues addressed in the work reported here were: (a) What is the sediment response to forcing by currents and waves? (b) What is the turbulence climate in the bottom boundary layer at this site? and (c) What is the rate at which settling leads to carbon sequestering in bottom sediments at offshore sites?
Active Control of Plasma Boundaries Using Edge Currents
Budny, Robert
response and low power levels. - independent of vessel magnetic penetration time scales. · Useful boundaries using edge currents has been demonstrated in numerous experiments to produce edge conditions fields on a faster time scale and with less power than external magnetic field coils. - fast time
An Unstable Elliptic Free Boundary Problem arising in Solid Combustion
Monneau, RÃ©gis
An Unstable Elliptic Free Boundary Problem arising in Solid Combustion R. Monneau Ecole Nationale in solid combustion. The maximal solution and every local minimizer of the energy are regular, that is, {u combustion, singularity, unstable problem, Aleksandrov reflection, unique blow-up limit, second variation
Connectivity of Confined Dense Networks: Boundary Effects and Scaling Laws
Goussev, Arseni O.
in statistical physics to analyze the effects that the boundaries of the geometry have on connectivity dense networks for each of these models. Finally, in order to demonstrate the versatility of our theory@toshiba-trel.com. #12;2 e.g., [1][3]). From a communications perspective, it is of paramount importance to understand
ORIGINAL PAPER Mechanical filtering by the boundary layer and fluidstructure
McHenry, Matt
ORIGINAL PAPER Mechanical filtering by the boundary layer and fluidstructure interaction force coefficient for fluid c speed of sound in water C integration constant Em Young's modulus moment of area k viscous drag coefficient L hydrodynamic force coefficient M bending moment N number
Ozone Chemistry in the High-Latitude Boundary Layer
Toohey, Darin W.
Ozone Chemistry in the High-Latitude Boundary Layer Linnea Avallone Department of Atmospheric layer ozone loss phenomenon · In situ observations of BrO at Arctic sites · Preliminary results from Antarctic experiments in 2002 and 2004 #12;Brief History · Springtime ozone loss observed at many sites
ROUTINE CLOUD-BOUNDARY ALGORITHM DEVELOPMENT FOR ARM MICROPULSE LIDAR
of Energy Office of Science ABSTRACT An operational cloud boundary algorithm (Wang and Sassen 2001) has been Associates, LLC under Contract No. DE-AC02- 98CH10886 with the U.S. Department of Energy. The publisher-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript
Boundary geometric control of a counter-current heat exchanger
Boyer, Edmond
Boundary geometric control of a counter-current heat exchanger Ahmed MAIDIa , Moussa DIAFb , Jean control of a counter-current heat exchanger whose control is designed considering a model based on two. The objective consists in controlling the internal fluid temperature, at the heat exchanger outlet
Mass exchange in the stable boundary layer by coherent structures
Leclerc, Monique Y.
) and a dense array of wind sensors to observe an indirect representation of roll vortices and plumes over the surface appears to pump energy near the surface thereby supporting the development of coherent structures gaseous exchange 1. Introduction Mass and energy exchange in the stable boundary layer remains poorly
NONLINEAR GEOSTROPHIC ADJUSTMENT IN THE PRESENCE OF A BOUNDARY
the initial disturbance, and Kelvin waves confined near the boundary. The theory provides simple formulae the fast-slow splitting, in spite of the fact that the frequency gap between the Kelvin waves and slow. In the case of a localised initial disturbance the total mass of the lowest-order slow component
A Theory of Spatial Regions with Indeterminate Boundaries
Leeds, University of
, School of Computer Studies, University of Leeds, Leeds, LS2 9JT, UK. email: fagc,ngottsg@scs.leeds review a first order theory of regions with crisp, well defined, boundaries. Then we present at Leeds has been to evaluate, extend and implement a theory 2 of space and time based upon Clarke
Large-Scale Streamwise Turbulent Structures in Hypersonic Boundary Layers
English, Benjamin L.
2013-04-22
Prior research in the field of boundary layer turbulence has identified streamwise-elongated large-scale turbulence structures in both low speed compressible and high speed (M=2.0) flow. No experimental work has been done in any flow of M> or =3...
Vacuum Casimir energy densities and field divergences at boundaries
Nicola Bartolo; Salvatore Butera; Margherita Lattuca; Roberto Passante; Lucia Rizzuto; Salvatore Spagnolo
2015-05-14
We consider and review the emergence of singular energy densities and field fluctuations at sharp boundaries or point-like field sources in the vacuum. The presence of singular energy densities of a field may be relevant from a conceptual point of view, because they contribute to the self-energy of the system. They should also generate significant gravitational effects. We first consider the case of the interface between a metallic boundary and the vacuum, and obtain the structure of the singular electric and magnetic energy densities at the interface through an appropriate limit from a dielectric to an ideal conductor. Then, we consider the case of a point-like source of the electromagnetic field, and show that also in this case the electric and magnetic energy densities show a singular structure at the source position. We discuss how, in both cases, these singularities give an essential contribution to the electromagnetic self-energy of the system; moreover, they solve an apparent inconsistency between the space integral of the field energy density and the average value of the field Hamiltonian. The singular behavior we find is softened, or even eliminated, for boundaries fluctuating in space and for extended field sources. We discuss in detail the case in which a reflecting boundary is not fixed in space but is allowed to move around an equilibrium position, under the effect of quantum fluctuations of its position. Specifically, we consider the simple case of a one-dimensional massless scalar field in a cavity with one fixed and one mobile wall described quantum-mechanically. We investigate how the possible motion of the wall changes the vacuum fluctuations and the energy density of the field, compared with the fixed-wall case. Also, we explicitly show how the fluctuating motion of the wall smears out the singular behaviour of the field energy density at the boundary.
Chow, Fotini Katopodes
models, such as the Weather Research and Forecasting (WRF) model, are in- creasingly used for high facilitates explicit resolution of complex terrain, even urban terrain, in the WRF mesoscale model. First gradient boundary conditions. Specified diurnal heating in a valley, producing anabatic winds, is used
Tackley, Paul J.
The interaction between the post-perovskite phase change and a thermo-chemical boundary layer near convection with the newly-discovered post-perovskite (PPV) phase change are used to characterize its depth. The strongly exothermic nature of the post-perovskite phase change induces an anti
Search for the decay B^+ \\to K_S^0 K_S^0 \\pi ^+
Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Lopez, L.; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Abrams, G.S.; Battaglia, M.; Brown, D.N.; Cahn, R.N.; Jacobsen, R.G.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Karlsruhe U., EKP /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /INFN, Naples /Naples U. /INFN, Naples /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /Pennsylvania U. /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /Rostock U. /Rutherford /DSM, DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Albany /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U., IFIC /Victoria U. /Warwick U. /Wisconsin U., Madison
2009-02-23
The authors search for charmless decays of charged B mesons to the three-body final state K{sub S}{sup 0}K{sub S}{sup 0}{pi}{sup +}. Using a data sample of 423.7 fb{sup -1} collected at the {Upsilon}(4S) resonance with the BABAR detector, corresponding to (465.1 {+-} 5.1) x 10{sup 6} B{bar B} pairs, they find no significant signal and determine a 90% confidence level upper limit on the branching fraction of 5.1 x 10{sup -7}.
Accumulating Particles at the Boundaries of a Laminar Flow
Michael Schindler; Peter Talkner; Marcin Kostur; Peter Hanggi
2007-06-25
The accumulation of small particles is analyzed in stationary flows through channels of variable width at small Reynolds number. The combined influence of pressure, viscous drag and thermal fluctuations is described by means of a Fokker-Planck equation for the particle density. It is shown that in the limit of vanishing particle size a uniform particle distribution is always approached in the long time limit. For extended spherical particles, conditions are specified that lead to inhomogeneous densities and consequently to particle accumulation and depletion. Hereby the boundary conditions for the particle density play a decisive role: The centers of spherical particles must keep the minimal distance of their radius from the fluid boundaries. The normal components of the forces acting on the sphere then may assume finite values which are diffusively transported into the bulk of the fluid.
Warm Bias and Parameterization of Boundary Upwelling in Ocean Models
Cessi, Paola; Wolfe, Christopher
2012-11-06
It has been demonstrated that Eastern Boundary Currents (EBC) are a baroclinic intensification of the interior circulation of the ocean due to the emergence of mesoscale eddies in response to the sharp buoyancy gradients driven by the wind-stress and the thermal surface forcing. The eddies accomplish the heat and salt transport necessary to insure that the subsurface flow is adiabatic, compensating for the heat and salt transport effected by the mean currents. The EBC thus generated occurs on a cross-shore scale of order 20-100 km, and thus this scale needs to be resolved in climate models in order to capture the meridional transport by the EBC. Our result indicate that changes in the near shore currents on the oceanic eastern boundaries are linked not just to local forcing, such as coastal changes in the winds, but depend on the basin-wide circulation as well.
Boundary quantum Knizhnik-Zamolodchikov equations and fusion
Nicolai Reshetikhin; Jasper Stokman; Bart Vlaar
2014-12-19
In this paper we extend our previous results concerning Jackson integral solutions of the boundary quantum Knizhnik-Zamolodchikov equations with diagonal K-operators to higher-spin representations of quantum affine $\\mathfrak{sl}_2$. First we give a systematic exposition of known results on $R$-operators acting in the tensor product of evaluation representations in Verma modules over quantum $\\mathfrak{sl}_2$. We develop the corresponding fusion of $K$-operators, which we use to construct diagonal $K$-operators in these representations. We construct Jackson integral solutions of the associated boundary quantum Knizhnik-Zamolodchikov equations and explain how in the finite-dimensional case they can be obtained from our previous results by the fusion procedure.
Cumulative theoretical uncertainties in lithium depletion boundary age
Tognelli, Emanuele; Degl'Innocenti, Scilla
2015-01-01
We performed a detailed analysis of the main theoretical uncertainties affecting the age at the lithium depletion boundary (LDB). To do that we computed almost 12000 pre-main sequence models with mass in the range [0.06, 0.4] M_sun by varying input physics (nuclear reaction cross-sections, plasma electron screening, outer boundary conditions, equation of state, and radiative opacity), initial chemical elements abundances (total metallicity, helium and deuterium abundances, and heavy elements mixture), and convection efficiency (mixing length parameter, alpha_ML). As a first step, we studied the effect of varying these quantities individually within their extreme values. Then, we analysed the impact of simultaneously perturbing the main input/parameters without an a priori assumption of independence. Such an approach allowed us to build for the first time the cumulative error stripe, which defines the edges of the maximum uncertainty region in the theoretical LDB age. We found that the cumulative error stripe ...
Study of interdomain boundary in diamagnetic domain structure in beryllium
Philip Lykov
2002-11-21
At low temperatures, in strong magnetic fields, the formation of a non-uniform magnetisation is possible in a single-crystal metal sample whose demagnetising factor along the field is close to unity. Namely, so-called Condon diamagnetic domain structure arises and disappears periodically with magnetic field. In this paper, the diamagnetic domain structure in beryllium single crystalis analysed. Directly, existence of diamagnetic domains in that sample was observed earlier by the muon spin precession (mSR) resonance peak splitting. A method is described that allows to calculate quantitative characteristics of the interdomain boundary using the muon histograms. The technique is based on the Marquardt minimisation procedure that has been modified in order to reduce the influence of noise on iterations convergence. Boundary volume fraction was calculated.
Applying Twisted Boundary Conditions for Few-body Nuclear Systems
Christopher Körber; Thomas Luu
2015-11-20
We describe and implement twisted boundary conditions for the deuteron and triton systems within finite-volumes using the nuclear lattice EFT formalism. We investigate the finite-volume dependence of these systems with different twists angles. We demonstrate how various finite-volume information can be used to improve calculations of binding energies in such a framework. Our results suggests that with appropriate twisting of boundaries, infinite-volume binding energies can be reliably extracted from calculations using modest volume sizes with cubic length $L\\approx8-14$ fm. Of particular importance is our derivation and numerical verification of three-body analogue of `i-periodic' twist angles that eliminate the leading order finite-volume effects to the three-body binding energy.
Applying Twisted Boundary Conditions for Few-body Nuclear Systems
Körber, Christopher
2015-01-01
We describe and implement twisted boundary conditions for the deuteron and triton systems within finite-volumes using the nuclear lattice EFT formalism. We investigate the finite-volume dependence of these systems with different twists angles. We demonstrate how various finite-volume information can be used to improve calculations of binding energies in such a framework. Our results suggests that with appropriate twisting of boundaries, infinite-volume binding energies can be reliably extracted from calculations using modest volume sizes with cubic length $L\\approx8-14$ fm. Of particular importance is our derivation and numerical verification of three-body analogue of `i-periodic' twist angles that eliminate the leading order finite-volume effects to the three-body binding energy.
Flavor twisted boundary conditions and the nucleon vector current
Jiang, F.-J.; Tiburzi, B. C.
2008-12-01
Using flavor twisted boundary conditions, we study nucleon matrix elements of the vector current. We twist only the active quarks that couple to the current. Finite volume corrections due to twisted boundary conditions are determined using partially twisted, partially quenched, heavy baryon chiral perturbation theory, which we develop for the graded group SU(7|5). Asymptotically these corrections are exponentially small in the volume, but can become pronounced for small twist angles. Utilizing the Breit frame does not mitigate volume corrections to nucleon vector current matrix elements. The derived expressions will allow for better controlled extractions of the isovector magnetic moment and the electromagnetic radii from simulations at zero lattice momentum. Our formalism, moreover, can be applied to any nucleon matrix elements.
On the Green function of linear evolution equations for a region with a boundary
George Krylov; Marko Robnik
2000-03-30
We derive a closed-form expression for the Green function of linear evolution equations with the Dirichlet boundary condition for an arbitrary region, based on the singular perturbation approach to boundary problems.
An evaluation of grain boundary engineering technology and processing scale-up
Zelinski, Jeffrey A
2005-01-01
Grain boundary engineering is the manipulation of low stacking-fault energy, face- centered cubic material microstructures to break the connectivity of the general grain boundary network through the addition of special ...
Boettcher, Markus
1 Magnetic Field Generation and Particle Energization at Relativistic Shear Boundaries. We find efficient magnetic field generation and particle energization at the shear boundary, driven generation (Colgate et al 2001, Medvedev & Loeb 1999) and nonthermal particle energization (Berezhko 1981
Immersed Boundary Methods in the Lattice Boltzmann Equation for Flow Simulation
Kang, Shin Kyu
2012-02-14
In this dissertation, we explore direct-forcing immersed boundary methods (IBM) under the framework of the lattice Boltzmann method (LBM), which is called the direct-forcing immersed boundary-lattice Boltzmann method (IB-LBM). First, we derive...
Boundary conditions, effective action, and Virasoro algebra for AdS?
Porfyriadis, Achilleas P
2010-01-01
We construct an effective action of General Relativity for small excitations from asymptotic transformations and use it to study conformal symmetry in the boundary of AdS3. By requiring finiteness of the boundary effective ...
PERCOLATION ON GRAIN BOUNDARY NETWORKS: APPLICATION TO FISSION GAS RELEASE IN NUCLEAR FUELS
Paul C. Millett
2012-02-01
The percolation behavior of grain boundary networks is characterized in two- and three-dimensional lattices with circular macroscale cross-sections that correspond to nuclear fuel elements. The percolation of gas bubbles on grain boundaries, and the subsequent percolation of grain boundary networks is the primary mechanism of fission gas release from nuclear fuels. Both radial cracks and radial gradients in grain boundary property distributions are correlated with the fraction of grain boundaries vented to the free surfaces. Our results show that cracks surprisingly do not significantly increase the percolation of uniform grain boundary networks. However, for networks with radial gradients in boundary properties, the cracks can considerably raise the vented grain boundary content.
An Examination of Configurations for Using Infrared to Measure Boundary Layer Transition
Freels, Justin Reed
2012-10-19
Infrared transition location estimates can be fast and useful measurements in wind tunnel and flight tests. Because turbulent boundary layers have a much higher rate of convective heat transfer than laminar boundary layers, a difference in surface...
12. First Results on the Regularity of the Free Boundary 12.1 ...
2007-02-22
12.1. Problem A: C1-regularity of the free boundary near low-energy points. In this lecture, we study the free boundary in Problem A near the low- energy points.
Influence of grain boundary energy on the nucleation of complexion transitions
Rohrer, Gregory S.
Influence of grain boundary energy on the nucleation of complexion transitions Stephanie A different transition tem- peratures. It has been hypothesized that higher energy grain boundaries have relative energies preferentially undergo complexion transitions. Our experiment uses a unique sandwich
Ovid'ko Ilya A.
99Amorphous intergranular boundaries as toughening elements in nanocrystalline ceramics © 2009-mail: ovidko@def.ipme.ru AMORPHOUS INTERGRANULAR BOUNDARIES AS TOUGHENING ELEMENTS IN NANOCRYSTALLINE CERAMICS ceramics. Within the model, im- mobile lattice dislocations are generated at amorphous intergranular
A non standard free-boundary problem arising from stratigraphy Gerard GAGNEUX
A non standard free-boundary problem arising from stratigraphy G´erard GAGNEUX Laboratory.4) #12;A non standard free-boundary problem arising from stratigraphy 3 · the initial condition: u(0
Massive Gravity from Higher Derivative Gravity with Boundary Conditions
Minjoon Park; Lorenzo Sorbo
2012-10-29
With an appropriate choice of parameters, a higher derivative theory of gravity can describe a normal massive sector and a ghost massless sector. We show that, when defined on an asymptotically de Sitter spacetime with Dirichlet boundary conditions, such a higher derivative gravity can provide a framework for a unitary theory of massive gravity in four spacetime dimensions. The resulting theory is free not only of higher derivative ghosts but also of the Boulware-Deser mode.
Boundary String Field Theory of the DDbar System
Kraus, P; Kraus, Per; Larsen, Finn
2001-01-01
We develop the boundary string field theory approach to tachyon condensation on the DDbar system. Particular attention is paid to the gauge fields, which combine with the tachyons in a natural way. We derive the RR-couplings of the system and express the result in terms of Quillen's superconnection. The result is related to an index theorem, and is thus shown to be exact.
On the outer boundary of the sunspot penumbra
B. Kalman
2002-02-06
Comparison of photographic observations and vector-magnetograph measurements demonstrate, that the outer boundary of the sunspot penumbra --even in complex sunspot groups-- closely follows the 0.075T isogauss line of the total value of the magnetic field, corresponding approximately to the equipartition value in the photosphere. Radio observations also show this feature. The thick penumbra model with interchange convection (Jahn and Schmidt, 1994) gives the best explanation of the penumbral structure.
On the extraction of spectral quantities with open boundary conditions
Mattia Bruno; Piotr Korcyl; Tomasz Korzec; Stefano Lottini; Stefan Schaefer
2014-11-19
We discuss methods to extract decay constants, meson masses and gluonic observables in the presence of open boundary conditions. The ensembles have been generated by the CLS effort and have 2+1 flavors of O(a)-improved Wilson fermions with a small twisted-mass term as proposed by L\\"uscher and Palombi. We analyse the effect of the associated reweighting factors on the computation of different observables.
Exchanges across Land-Water-Scape Boundaries in Urban Systems
Vermont, University of
, and institutional behavior Key words: urban; cities; watershed; boundaries; nitrate; water; pollution; land cover Pollution M.L. Cadenasso,a S.T.A. Pickett,b P.M. Groffman,b L.E. Band,c G.S. Brush,d M.F. Galvin,e J Resources, University of Vermont, Burlington, Vermont, USA k Baltimore City Department of Public Works
On Lyapunov boundary control of unstable magnetohydrodynamic plasmas
Tasso, H. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, 85748 Garching bei Muenchen (Germany); Throumoulopoulos, G. N. [Department of Physics, University of Ioannina, Association Euratom-Hellenic Republic, GR 451 10 Ioannina (Greece)
2013-02-15
Starting from a simple, marginally stable model considered for Lyapunov based boundary control of flexible mechanical systems, we add a term driving an instability and prove that for an appropriate control condition the system can become Lyapunov stable. A similar approximate extension is found for the general energy principle of linearized magnetohydrodynamics. The implementation of such external instantaneous actions may, however, impose challenging constraints for fusion plasmas.
Theory and Fluid Simulations of Boundary Plasma Fluctuations
Cohen, R H; LaBombard, B; LoDestro, L L; Rognlien, T D; Ryutov, D D; Terry, J L; Umansky, M V; Xu, X Q; Zweben, S
2007-01-09
Theoretical and computational investigations are presented of boundary plasma microturbulence that take into account important effects of the geometry of diverted tokamaks--in particular, the effect of x-point magnetic shear and the termination of field lines on divertor plates. We first generalize our previous 'heuristic boundary condition' which describes, in a lumped model, the closure of currents in the vicinity of the x-point region to encompass three current-closure mechanisms. We then use this boundary condition to derive the dispersion relation for low-beta flute-like modes in the divertor-leg region under the combined drives of curvature, sheath impedance, and divertor tilt effects. The results indicate the possibility of strongly growing instabilities, driven by sheath boundary conditions, and localized in either the private or common flux region of the divertor leg depending on the radial tilt of divertor plates. We re-visit the issue of x-point effects on blobs, examining the transition from blobs terminated by x-point shear to blobs that extend over both the main SOL and divertor legs. We find that, for a main-SOL blob, this transition occurs without a free-acceleration period as previously thought, with x-point termination conditions applying until the blob has expanded to reach the divertor plate. We also derive propagation speeds for divertor-leg blobs. Finally, we present fluid simulations of the C-Mod tokamak from the BOUT edge fluid turbulence code, which show main-SOL blob structures with similar spatial characteristics to those observed in the experiment, and also simulations which illustrate the possibility of fluctuations confined to divertor legs.
Approximations of very weak solutions to boundary-value problems.
Berggren, Martin Olof
2003-03-01
Standard weak solutions to the Poisson problem on a bounded domain have square-integrable derivatives, which limits the admissible regularity of inhomogeneous data. The concept of solution may be further weakened in order to define solutions when data is rough, such as for inhomogeneous Dirichlet data that is only square-integrable over the boundary. Such very weak solutions satisfy a nonstandard variational form (u, v) = G(v). A Galerkin approximation combined with an approximation of the right-hand side G defines a finite-element approximation of the very weak solution. Applying conforming linear elements leads to a discrete solution equivalent to the text-book finite-element solution to the Poisson problem in which the boundary data is approximated by L{sub 2}-projections. The L{sub 2} convergence rate of the discrete solution is O(h{sub s}) for some s {element_of} (0,1/2) that depends on the shape of the domain, asserting a polygonal (two-dimensional) or polyhedral (three-dimensional) domain without slits and (only) square-integrable boundary data.
Coupled wake boundary layer model of wind-farms
Stevens, Richard J A M; Meneveau, Charles
2014-01-01
We present and test a coupled wake boundary layer (CWBL) model that describes the distribution of the power output in a wind-farm. The model couples the traditional, industry-standard wake expansion/superposition approach with a top-down model for the overall wind-farm boundary layer structure. The wake expansion/superposition model captures the effect of turbine positioning, while the top-down portion adds the interaction between the wind-turbine wakes and the atmospheric boundary layer. Each portion of the model requires specification of a parameter that is not known a-priori. For the wake model the wake expansion coefficient is required, while the top-down model requires an effective span-wise turbine spacing within which the model's momentum balance is relevant. The wake expansion coefficient is obtained by matching the predicted mean velocity at the turbine from both approaches, while the effective span-wise turbine spacing depends on turbine positioning and thus can be determined from the wake expansion...
Gapped Domain Walls, Gapped Boundaries and Topological Degeneracy
Tian Lan; Juven Wang; Xiao-Gang Wen
2014-11-26
Gapped domain walls, as topological line defects between 2+1D topologically ordered states, are examined. We provide simple criteria to determine the existence of gapped domain walls, which apply to both Abelian and non-Abelian topological orders. Our criteria also determine which 2+1D topological orders must have gapless edge modes, namely which 1+1D global gravitational anomalies ensure gaplessness. Furthermore, we introduce a new mathematical object, the tunneling matrix $\\mathcal W$, whose entries are the fusion-space dimensions $\\mathcal W_{ia}$, to label different types of gapped domain walls. By studying many examples, we find evidence that the tunneling matrices are powerful quantities to classify different types of gapped domain walls. Since a gapped boundary is a gapped domain wall between a bulk topological order and the vacuum, regarded as the trivial topological order, our theory of gapped domain walls inclusively contains the theory of gapped boundaries. In addition, we derive a topological ground state degeneracy formula, applied to arbitrary orientable spatial 2-manifolds with gapped domain walls, including closed 2-manifolds and open 2-manifolds with gapped boundaries.
Stability boundaries for wrinkling in highly stretched elastic sheets
Qingdu Li; Timothy J. Healey
2015-09-14
We determine stability boundaries for the wrinkling of highly uni-directionally stretched, finely thin, rectangular elastic sheets. For a given fine thickness and length, a stability boundary here is a curve in the parameter plane, aspect ratio vs. the macroscopic strain; the values on one side of the boundary are associated with a flat, unwrinkled state, while wrinkled configurations correspond to all values on the other. In our recent work we demonstrated the importance of finite elasticity in the membrane part of such a model in order to capture the correct phenomena. Here we present and compare results for four distinct models:(i) the popular F\\"oppl-von K\\'arm\\'an plate model (FvK), (ii) a correction of the latter, used in our earlier work, in which the approximate 2D F\\"oppl strain tensor is replaced by the exact Green strain tensor, (iii) and (iv): effective 2D finite-elasticity membrane models based on 3D incompressible neo-Hookean and Mooney-Rivlin materials, respectively. In particular, (iii) and (iv) are superior models for elastomers. The 2D nonlinear, hyperelastic models (ii)-(iv) all incorporate the same quadratic bending energy used in FvK. Our results illuminate serious shortcomings of the latter in this problem, while also pointing to inaccuracies of model (ii), in spite of yielding the correct qualitative phenomena in our earlier work. In each of these, the shortcoming is a due to a deficiency of the membrane part of the model.
Improving Subtropical Boundary Layer Cloudiness in the 2011 NCEP GFS
Fletcher, J. K.; Bretherton, Christopher S.; Xiao, Heng; Sun, Ruiyu N.; Han, J.
2014-09-23
The current operational version of National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) shows significant low cloud bias. These biases also appear in the Coupled Forecast System (CFS), which is developed from the GFS. These low cloud biases degrade seasonal and longer climate forecasts, particularly of short-wave cloud radiative forcing, and affect predicted sea surface temperature. Reducing this bias in the GFS will aid the development of future CFS versions and contributes to NCEP's goal of unified weather and climate modelling. Changes are made to the shallow convection and planetary boundary layer parameterisations to make them more consistent with current knowledge of these processes and to reduce the low cloud bias. These changes are tested in a single-column version of GFS and in global simulations with GFS coupled to a dynamical ocean model. In the single-column model, we focus on changing parameters that set the following: the strength of shallow cumulus lateral entrainment, the conversion of updraught liquid water to precipitation and grid-scale condensate, shallow cumulus cloud top, and the effect of shallow convection in stratocumulus environments. Results show that these changes improve the single-column simulations when compared to large eddy simulations, in particular through decreasing the precipitation efficiency of boundary layer clouds. These changes, combined with a few other model improvements, also reduce boundary layer cloud and albedo biases in global coupled simulations.
Recursive recovery of Markov transition probabilities from boundary value data
Patch, S.K.
1994-04-01
In an effort to mathematically describe the anisotropic diffusion of infrared radiation in biological tissue Gruenbaum posed an anisotropic diffusion boundary value problem in 1989. In order to accommodate anisotropy, he discretized the temporal as well as the spatial domain. The probabilistic interpretation of the diffusion equation is retained; radiation is assumed to travel according to a random walk (of sorts). In this random walk the probabilities with which photons change direction depend upon their previous as well as present location. The forward problem gives boundary value data as a function of the Markov transition probabilities. The inverse problem requires finding the transition probabilities from boundary value data. Problems in the plane are studied carefully in this thesis. Consistency conditions amongst the data are derived. These conditions have two effects: they prohibit inversion of the forward map but permit smoothing of noisy data. Next, a recursive algorithm which yields a family of solutions to the inverse problem is detailed. This algorithm takes advantage of all independent data and generates a system of highly nonlinear algebraic equations. Pluecker-Grassmann relations are instrumental in simplifying the equations. The algorithm is used to solve the 4 {times} 4 problem. Finally, the smallest nontrivial problem in three dimensions, the 2 {times} 2 {times} 2 problem, is solved.
Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly
Free Boundary, High Beta Equilibrium in a Large Aspect Ratio Tokamak with Nearly Circular Plasmaboundary, highbeta equi libria in large aspect ratio tokamaks with a nearly circular plasma boundary in tokamaks for the purpose of developing an economic fusion reactor. It has long been recognized
An Embedded Boundary Integral Solver for the Unsteady Incompressible Navier-Stokes Equations1
Zorin, Denis
An Embedded Boundary Integral Solver for the Unsteady Incompressible Navier-Stokes Equations1-Stokes operator discretization is done using boundary integrals and structured-grid finite elements. We use a two is formulated as a double-layer boundary integral equation. Domain integrals are computed via finite elements
Coremantle boundary topography as a possible constraint on lower mantle chemistry and dynamics
Rhoads, James
Coremantle boundary topography as a possible constraint on lower mantle chemistry and dynamics November 2009 Editor: Y. Ricard Keywords: mantle convection coremantle boundary CMB topography), each of which uniquely affects the topography on Earth's coremantle boundary (CMB). The thermochemical
Boundary energy of the open XXZ chain from new exact solutions
Rajan Murgan; Rafael I. Nepomechie; Chi Shi
2005-12-05
Bethe Ansatz solutions of the open spin-1/2 integrable XXZ quantum spin chain at roots of unity with nondiagonal boundary terms containing two free boundary parameters have recently been proposed. We use these solutions to compute the boundary energy (surface energy) in the thermodynamic limit.
Sharp boundaries of small-and middle-scale solar wind structures
Richardson, John
Sharp boundaries of small- and middle-scale solar wind structures M. O. Riazantseva1 and G. N wind ion flux changes which are not due to shocks. These changes are boundaries of small- and middle boundaries of small- and middle-scale solar wind structures, J. Geophys. Res., 110, A12110, doi:10
Richardson, John
The characteristics of sharp (small-scale) boundaries of solar wind plasma and magnetic field are the boundaries of small-scale and mid- dle-scale solar wind structures. We describe the behavior of the solar boundaries of small and medium scale solar wind plasma structures which we identify by looking for sharp
Comparing calculated and measured grain boundary energies in nickel Gregory S. Rohrer a
Rohrer, Gregory S.
Comparing calculated and measured grain boundary energies in nickel Gregory S. Rohrer a , Elizabeth boundary energy data sets for Ni. Using these results, we perform the first large-scale comparison between measured and computed grain boundary energies. While the overall correlation between experimental
Dielectric Boundary Force in Molecular Solvation with the PoissonBoltzmann Free Energy: A Shape
Li, Bo
Dielectric Boundary Force in Molecular Solvation with the PoissonÂBoltzmann Free Energy: A Shape boundary force acting on such a boundary is the negative first variation of the elec- trostatic free energy [17,18,35,43,44]. Such a predefined interface is used to compute the solvation free energy as the sum
Response of the bottom boundary layer over a sloping shelf to variations in alongshore wind
to a great extent by flows in the surface and bottom boundary layers (BBL). Wind forcing generates crossResponse of the bottom boundary layer over a sloping shelf to variations in alongshore wind A boundary layer over a sloping shelf to variations in alongshore wind, J. Geophys. Res., 110, C10S09, doi:10
Relative grain boundary area and energy distributions in nickel Jia Li, Shen J. Dillon 1
Rohrer, Gregory S.
Relative grain boundary area and energy distributions in nickel Jia Li, Shen J. Dillon 1 , Gregory crystallographic parameters, a quantity that will be referred to as the grain boundary energy distribution (GBED20]. The first comprehensive measurement of the grain boundary energy distribution was carried out for Mg
Uranium vacancy mobility at the ?5 symmetric tilt and ?5 twist grain boundaries in UO?
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Uberuaga, Blas Pedro; Andersson, David A.
2015-10-01
Ionic transport at grain boundaries in oxides dictates a number of important phenomena, from ionic conductivity to sintering to creep. For nuclear fuels, it also influences fission gas bubble nucleation and growth. Here, using a combination of atomistic calculations and object kinetic Monte Carlo (okMC) simulations, we examine the kinetic pathways associated with uranium vacancies at two model grain boundaries in UO2. The barriers for vacancy motion were calculated using the nudged elastic band method at all uranium sites at each grain boundary and were used as the basis of the okMC simulations. For both boundaries considered – a simplemore »tilt and a simple twist boundary – the mobility of uranium vacancies is significantly higher than in the bulk. For the tilt boundary, there is clearly preferred migration along the tilt axis as opposed to in the perpendicular direction while, for the twist boundary, migration is essentially isotropic within the boundary plane. These results show that cation defect mobility in fluorite-structured materials is enhanced at certain types of grain boundaries and is dependent on the boundary structure with the tilt boundary exhibiting higher rates of migration than the twist boundary.« less
SAID/SAPSrelated VLF waves and the outer radiation belt boundary
Santolik, Ondrej
SAID/SAPSrelated VLF waves and the outer radiation belt boundary Evgeny Mishin,1 Jay Albert,1 for the alteration of the outer radiation belt boundary during (sub)storms. Citation: Mishin, E., J. Albert, and O. Santolik (2011), SAID/SAPSrelated VLF waves and the outer radiation belt boundary, Geophys. Res. Lett., 38
Matched interface and boundary (MIB) method for elliptic problems with sharp-edged interfaces
Zhou, Yongcheng
Matched interface and boundary (MIB) method for elliptic problems with sharp-edged interfaces with sharp-edged interfaces, thin-layered interfaces and interfaces that intersect with geometric boundary. This work generalizes the matched interface and boundary (MIB) method previously designed for solving
H. Itoyama; A. Mironov; A. Morozov
2007-12-02
We describe an algebro-geometric construction of polygon-bounded minimal surfaces in ADS_5, based on consideration of what we call the "boundary ring" of polynomials. The first non-trivial example of the Nambu-Goto (NG) solutions for Z_6-symmetric hexagon is considered in some detail. Solutions are represented as power series, of which only the first terms are evaluated. The NG equations leave a number of free parameters (a free function). Boundary conditions, which fix the free parameters, are imposed on truncated series. It is still unclear if explicit analytic formulas can be found in this way, but even approximate solutions, obtained by truncation of power series, can be sufficient to investigate the Alday-Maldacena -- BDS/BHT version of the string/gauge duality.
Boundary conditions for conformally coupled scalar in AdS$_4$
Jae-Hyuk Oh
2015-02-05
We consider conformally coupled scalar with $\\phi^4$ coupling in AdS$_4$ and study its various boundary conditions on AdS boundary. We have obtained perturbative solutions of equation of motion of the conformally coupled scalar with power expansion order by order in $\\phi^4$ coupling $\\lambda$ up to $\\lambda^2$ order. In its dual CFT, we get 2,4 and 6 point functions by using this solution with Dirichlet and Neumann boundary conditions via AdS/CFT dictionary. We also consider marginal deformation on AdS boundary and get its on-shell and boundary effective actions.
Crystallographic Characteristics of Grain Boundaries in Dense Yttria-Stabilized Zirconia
Lam Helmick; Shen J. Dillon; Kirk Gerdes; Randall Gemmen; Gregory S. Rohrer; Sridhar Seetharaman; Paul A. Salvador
2010-04-01
Grain-boundary plane, misorientation angle, grain size, and grain-boundary energy distributions were quantified using electron backscatter diffraction data for dense polycrystalline yttria-stabilized zirconia, to understand interfacial crystallography in solid oxide fuel cells. Tape-cast samples were sintered at 14501C for 4 h and annealed for at least 100 h between 8001C and 16501C. Distributions obtained from both three-dimensional (3D) reconstructions and stereological analyses of 2D sections demonstrated that the (100) boundary planes {(111)} have relative areas larger {smaller} than expected in a random distribution, and that the boundary plane distribution is inversely correlated to the boundary energy distribution.
Molecular dynamics simulations of grain boundary thermal resistance in UO2
Tianyi Chen; Di Chen; Bulent H. Sencer; Lin Shao
2014-09-01
By means of molecular dynamics (MD) simulations, we have calculated Kaptiza resistance of UO2 with or without radiation damage. For coincident site lattice boundaries of different configurations, the boundary thermal resistance of unirradiated UO2 can be well described by a parameter-reduced formula by using boundary energies as variables. We extended the study to defect-loaded UO2 by introducing damage cascades in close vicinity to the boundaries. Following cascade annealing and defect migrations towards grain boundaries, the boundary energy increases and so does Kaptiza resistance. The correlations between these two still follow the same formula extracted from the unirradiated UO2. The finding will benefit multi-scale modeling of UO2 thermal properties under extreme radiation conditions by combining effects from boundary configurations and damage levels.
Turbine exhaust diffuser with region of reduced flow area and outer boundary gas flow
Orosa, John
2014-03-11
An exhaust diffuser system and method for a turbine engine. The outer boundary may include a region in which the outer boundary extends radially inwardly toward the hub structure and may direct at least a portion of an exhaust flow in the diffuser toward the hub structure. At least one gas jet is provided including a jet exit located on the outer boundary. The jet exit may discharge a flow of gas downstream substantially parallel to an inner surface of the outer boundary to direct a portion of the exhaust flow in the diffuser toward the outer boundary to effect a radially outward flow of at least a portion of the exhaust gas flow toward the outer boundary to balance an aerodynamic load between the outer and inner boundaries.
Role of the basin boundary conditions in gravity wave turbulence
Luc Deike; Benjamin Miquel; Pablo Gutiérrez-Matus; Timothée Jamin; Benoit Semin; Michael Berhanu; Eric Falcon; Félicien Bonnefoy
2015-09-02
Gravity wave turbulence is studied experimentally in a large wave basin where irregular waves are generated unidirectionally. The role of the basin boundary conditions (absorbing or reflecting) and of the forcing properties are investigated. To that purpose, an absorbing sloping beach opposite to the wavemaker can be replaced by a reflecting vertical wall. We observe that the wave field properties depend strongly on these boundary conditions. Quasi-one dimensional field of nonlinear waves propagate before to be damped by the beach whereas a more multidirectional wave field is observed with the wall. In both cases, the wave spectrum scales as a frequency-power law with an exponent that increases continuously with the forcing amplitude up to a value close to -4, which is the value predicted by the weak turbulence theory. The physical mechanisms involved are probably different according to the boundary condition used, but cannot be easily discriminated with only temporal measurements. We have also studied freely decaying gravity wave turbulence in the closed basin. No self-similar decay of the spectrum is observed, whereas its Fourier modes decay first as a time power law due to nonlinear mechanisms, and then exponentially due to linear viscous damping. We estimate the linear, nonlinear and dissipative time scales to test the time scale separation that highlights the important role of a large scale Fourier mode. By estimation of the mean energy flux from the initial decay of wave energy, the Kolmogorov-Zakharov constant is evaluated and found to be compatible with a recent theoretical value.
Role of the basin boundary conditions in gravity wave turbulence
Luc Deike; Benjamin Miquel; Pablo Gutiérrez-Matus; Timothée Jamin; Benoit Semin; Sébastien Aumaitre; Michael Berhanu; Eric Falcon; Félicien BONNEFOY
2014-12-16
Gravity wave turbulence is studied experimentally in a large wave basin where irregular waves are generated unidirectionally. The role of the basin boundary conditions (absorbing or reflecting) and of the forcing properties are investigated. To that purpose, an absorbing sloping beach opposite to the wavemaker can be replaced by a reflecting vertical wall. We observe that the wave field properties depend strongly on these boundary conditions. Quasi-one dimensional field of nonlinear waves propagate before to be damped by the beach whereas a more multidirectional wave field is observed with the wall. In both cases, the wave spectrum scales as a frequency-power law with an exponent that increases continuously with the forcing amplitude up to a value close to -4, which is the value predicted by the weak turbulence theory. The physical mechanisms involved are probably different according to the boundary condition used, but cannot be easily discriminated with only temporal measurements. We have also studied freely decaying gravity wave turbulence in the closed basin. No self-similar decay of the spectrum is observed, whereas its Fourier modes decay first as a time power law due to nonlinear mechanisms, and then exponentially due to linear viscous damping. We estimate the linear, nonlinear and dissipative time scales to test the time scale separation that highlights the important role of a large scale Fourier mode. By estimation of the mean energy flux from the initial decay of wave energy, the Kolmogorov-Zakharov constant is evaluated and found to be compatible with a recent theoretical value.
Conformally covariant boundary correlation functions with a quantum group
Kalle Kytölä; Eveliina Peltola
2014-10-23
Particular boundary correlation functions of conformal field theory are needed to answer some questions related to random conformally invariant curves known as Schramm-Loewner evolutions (SLE). In this article, we introduce a correspondence and establish its fundamental properties, which are used in companion articles for explicitly solving two such problems. The correspondence associates Coulomb gas type integrals to vectors in a tensor product representation of a quantum group, a q-deformation of the Lie algebra sl2. We show that desired properties of the functions are guaranteed by natural representation theoretical properties of the vectors.
ARM - Field Campaign - Boundary Layer CO2 Using CW Lidar
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01) (See22, 2012IIIAtlanticMarine BoundarygovCampaignsBoundary
ARM - Field Campaign - Lower Atmospheric Boundary Layer Experiment
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach HomeA Better Anode Design to Improve4AJ01)govCampaignsFIRE-Arctic-govCampaignsLower Atmospheric Boundary
Frictional anisotropy under boundary lubrication: effect of surface texture.
Ajayi, O. O.; Erck, R. A.; Lorenzo-Martin, C.; Fenske, G. R.; Energy Systems
2009-06-15
The friction coefficient was measured under boundary lubrication with a ball-on-flat contact configuration in unidirectional sliding. The ball was smooth and hardened 52100 steel. Discs were made from case-carburized and hardened 4620, annealed 1080, and 1018 steels with directionally ground surfaces. A synthetic lubricant of stock polyalphaolefin was used for testing. During testing with each material, a frictional spike was observed whenever the ball slid parallel to the grinding ridge on the disc surface. The average friction coefficient for all tests was about 0.1, which is typical for the boundary lubrication regime. The magnitude of the frictional spikes, which reached as high as a friction coefficient of 0.25, and their persistence depended on the hardness of the disc surface. On the basis of elastohydrodynamic theory, coupled with the observation of severe plastic deformation on the ridges parallel to the sliding direction, the frictional spike could be due to localized plastic deformation on the disc surface at locations of minimal thickness for the lubricant fluid film. This hypothesis was further supported by lack of frictional spikes in tests using discs coated with a thin film of diamond-like carbon, in which plastic deformation is minimal.
Optimized boundary driven flows for dynamos in a sphere
Khalzov, I. V.; Brown, B. P.; Cooper, C. M.; Weisberg, D. B.; Forest, C. B. [Center for Magnetic Self Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)
2012-11-15
We perform numerical optimization of the axisymmetric flows in a sphere to minimize the critical magnetic Reynolds number Rm{sub cr} required for dynamo onset. The optimization is done for the class of laminar incompressible flows of von Karman type satisfying the steady-state Navier-Stokes equation. Such flows are determined by equatorially antisymmetric profiles of driving azimuthal (toroidal) velocity specified at the spherical boundary. The model is relevant to the Madison plasma dynamo experiment, whose spherical boundary is capable of differential driving of plasma in the azimuthal direction. We show that the dynamo onset in this system depends strongly on details of the driving velocity profile and the fluid Reynolds number Re. It is found that the overall lowest Rm{sub cr} Almost-Equal-To 200 is achieved at Re Almost-Equal-To 240 for the flow, which is hydrodynamically marginally stable. We also show that the optimized flows can sustain dynamos only in the range Rm{sub cr}
Mixing at the external boundary of a submerged turbulent jet
A. Eidelman; T. Elperin; N. Kleeorin; G. Hazak; I. Rogachevskii; O. Sadot; I. Sapir-Katiraie
2009-05-11
We study experimentally and theoretically mixing at the external boundary of a submerged turbulent jet. In the experimental study we use Particle Image Velocimetry and an Image Processing Technique based on the analysis of the intensity of the Mie scattering to determine the spatial distribution of tracer particles. An air jet is seeded with the incense smoke particles which are characterized by large Schmidt number and small Stokes number. We determine the spatial distributions of the jet fluid characterized by a high concentration of the particles and of the ambient fluid characterized by a low concentration of the tracer particles. In the data analysis we use two approaches, whereby one approach is based on the measured phase function for the study of the mixed state of two fluids. The other approach is based on the analysis of the two-point second-order correlation function of the particle number density fluctuations generated by tangling of the gradient of the mean particle number density by the turbulent velocity field. This gradient is formed at the external boundary of a submerged turbulent jet. We demonstrate that PDF of the phase function of a jet fluid penetrating into an external flow and the two-point second-order correlation function of the particle number density do not have universal scaling and cannot be described by a power-law function. The theoretical predictions made in this study are in a qualitative agreement with the obtained experimental results.
Multiscale molecular dynamics using the matched interface and boundary method
Geng Weihua [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Wei, G.W., E-mail: wei@math.msu.ed [Department of Mathematics, Michigan State University, East Lansing, MI 48824 (United States); Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824 (United States)
2011-01-20
The Poisson-Boltzmann (PB) equation is an established multiscale model for electrostatic analysis of biomolecules and other dielectric systems. PB based molecular dynamics (MD) approach has a potential to tackle large biological systems. Obstacles that hinder the current development of PB based MD methods are concerns in accuracy, stability, efficiency and reliability. The presence of complex solvent-solute interface, geometric singularities and charge singularities leads to challenges in the numerical solution of the PB equation and electrostatic force evaluation in PB based MD methods. Recently, the matched interface and boundary (MIB) method has been utilized to develop the first second order accurate PB solver that is numerically stable in dealing with discontinuous dielectric coefficients, complex geometric singularities and singular source charges. The present work develops the PB based MD approach using the MIB method. New formulation of electrostatic forces is derived to allow the use of sharp molecular surfaces. Accurate reaction field forces are obtained by directly differentiating the electrostatic potential. Dielectric boundary forces are evaluated at the solvent-solute interface using an accurate Cartesian-grid surface integration method. The electrostatic forces located at reentrant surfaces are appropriately assigned to related atoms. Extensive numerical tests are carried out to validate the accuracy and stability of the present electrostatic force calculation. The new PB based MD method is implemented in conjunction with the AMBER package. MIB based MD simulations of biomolecules are demonstrated via a few example systems.
Fluorescence photon migration by the boundary element method
Fedele, Francesco; Eppstein, Margaret J. . E-mail: maggie.eppstein@uvm.edu; Laible, Jeffrey P.; Godavarty, Anuradha; Sevick-Muraca, Eva M.
2005-11-20
The use of the boundary element method (BEM) is explored as an alternative to the finite element method (FEM) solution methodology for the elliptic equations used to model the generation and transport of fluorescent light in highly scattering media, without the need for an internal volume mesh. The method is appropriate for domains where it is reasonable to assume the fluorescent properties are regionally homogeneous, such as when using highly specific molecularly targeted fluorescent contrast agents in biological tissues. In comparison to analytical results on a homogeneous sphere, BEM predictions of complex emission fluence are shown to be more accurate and stable than those of the FEM. Emission fluence predictions made with the BEM using a 708-node mesh, with roughly double the inter-node spacing of boundary nodes as in a 6956-node FEM mesh, match experimental frequency-domain fluorescence emission measurements acquired on a 1087 cm{sup 3} breast-mimicking phantom at least as well as those of the FEM, but require only 1/8 to 1/2 the computation time.
Thermographic analysis of turbulent non-isothermal water boundary layer
Znamenskaya, Irina A
2015-01-01
The paper is devoted to the investigation of the turbulent water boundary layer in the jet mixing flows using high-speed infrared (IR) thermography. Two turbulent mixing processes were studied: a submerged water jet impinging on a flat surface and two intersecting jets in a round disc-shaped vessel. An infrared camera (FLIR Systems SC7700) was focused on the window transparent for IR radiation; it provided high-speed recordings of heat fluxes from a thin water layer close to the window. Temperature versus time curves at different points of water boundary layer near the wall surface were acquired using the IR camera with the recording frequency of 100 Hz. The time of recording varied from 3 till 20 min. The power spectra for the temperature fluctuations at different points on the hot-cold water mixing zone were calculated using the Fast Fourier Transform algorithm. The obtained spectral behavior was compared to the Kolmogorov "-5/3 spectrum" (a direct energy cascade) and the dual-cascade scenario predicted for...
A Convective-like Energy-Stable Open Boundary Condition for Simulations of Incompressible Flows
Dong, Suchuan
2015-01-01
We present a new energy-stable open boundary condition, and an associated numerical algorithm, for simulating incompressible flows with outflow/open boundaries. This open boundary condition ensures the energy stability of the system, even when strong vortices or backflows occur at the outflow boundary. Under certain situations it can be reduced to a form that can be analogized to the usual convective boundary condition. One prominent feature of this boundary condition is that it provides a control over the velocity on the outflow/open boundary. This is not available with the other energy-stable open boundary conditions from previous works. Our numerical algorithm treats the proposed open boundary condition based on a rotational velocity-correction type strategy. It gives rise to a Robin-type condition for the discrete pressure and a Robin-type condition for the discrete velocity on the outflow/open boundary, respectively at the pressure and the velocity sub-steps. We present extensive numerical experiments on...
Hartmann, Frederick
Investigating Possible Boundaries Between Convergence and Divergence Frederick Hartmann (frederick.hartmann
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Karen Johnson; Michael Jensen
ARSCL: cloud boundaries from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR
Computer simulation study of the structure of vacancies in grain boundaries
Brokman, A.; Bristowe, P.D.; Balluffi, R.W.
1981-01-01
The structure of vacancies in grain boundaries has been investigated by computer molecular statics employing pairwise potentials. In order to gain an impression of the vacancy structures which may occur generally, a number of variables was investigated including: metal type, boundary type, degree of lattice coincidence and choice of boundary site. In all cases the vacancies remained as distinguishable point defects in the relatively irregular boundary structures. However, it was found that the vacancy often induced relatively large atomic displacements in the core of the boundary. These displacements often occurred only in the direct vicinity of the vacancy, but in certain cases they were widely distributed in the boundary, sometimes at surprisingly large distances.
Consideration of Grain Size Distribution in the Diffusion of Fission Gas to Grain Boundaries
Paul C. Millett; Yongfeng Zhang; Michael R. Tonks; S. B. Biner
2013-09-01
We analyze the accumulation of fission gas on grain boundaries in a polycrystalline microstructure with a distribution of grain sizes. The diffusion equation is solved throughout the microstructure to evolve the gas concentration in space and time. Grain boundaries are treated as infinite sinks for the gas concentration, and we monitor the cumulative gas inventory on each grain boundary throughout time. We consider two important cases: first, a uniform initial distribution of gas concentration without gas production (correlating with post-irradiation annealing), and second, a constant gas production rate with no initial gas concentration (correlating with in-reactor conditions). The results show that a single-grain-size model, such as the Booth model, over predicts the gas accumulation on grain boundaries compared with a polycrystal with a grain size distribution. Also, a considerable degree of scatter, or variability, exists in the grain boundary gas accumulation when comparing all of the grain boundaries in the microstructure.
Miguel Alcubierre; Jose M. Torres
2014-11-06
We introduce a set of constraint preserving boundary conditions for the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation of the Einstein evolution equations in spherical symmetry, based on its hyperbolic structure. While the outgoing eigenfields are left to propagate freely off the numerical grid, boundary conditions are set to enforce that the incoming eigenfields don't introduce spurious reflections and, more importantly, that there are no fields introduced at the boundary that violate the constraint equations. In order to do this we adopt two different approaches to set boundary conditions for the extrinsic curvature, by expressing either the radial or the time derivative of its associated outgoing eigenfield in terms of the constraints. We find that these boundary conditions are very robust in practice, allowing us to perform long lasting evolutions that remain accurate and stable, and that converge to a solution that satisfies the constraints all the way to the boundary.
Localization effect for a spectral problem in a perforated domain with Fourier boundary cconditions
Valeria Chiado Piat; Iryna Pankratova; Andrey Piatnitski
2012-11-16
We consider a homogenization of elliptic spectral problem stated in a perforated domain, Fourier boundary conditions being imposed on the boundary of perforation. The presence of a locally periodic coefficient in the boundary operator gives rise to the effect of a localization of the eigenfunctions. Moreover, the limit behaviour of the lower part of the spectrum can be described in terms of an auxiliary harmonic oscillator operator. We describe the asymptotics of the eigenpairs and derive the estimates for the rate of convergence.
THE HELIOTAIL REVEALED BY THE INTERSTELLAR BOUNDARY EXPLORER
McComas, D. J.; Dayeh, M. A.; Livadiotis, G.; Funsten, H. O.; Schwadron, N. A.
2013-07-10
Recent combined observations from the first three years of Interstellar Boundary Explorer (IBEX) data allow us to examine the heliosphere's downwind region-the heliotail-for the first time. In contrast to a preliminary identification of a narrow ''offset heliotail'' structure, we find a broad slow solar wind plasma sheet crossing essentially the entire downwind side of the heliosphere at low to mid-latitudes, with fast wind tail regions to the north and south. The slow wind plasma sheet exhibits the steepest ENA spectra in the IBEX sky maps, appears as a two-lobed structure (lobes on the port and starboard sides), and is twisted in the sense of (but at a smaller angle than) the external magnetic field. The overall heliotail structure clearly demonstrates the intermediate nature of the heliosphere's interstellar interaction, where both the external dynamic and magnetic pressures strongly affect the heliosphere.
A boundary integral formalism for stochastic ray tracing in billiards
David J. Chappell; Gregor Tanner
2014-11-06
Determining the flow of rays or particles driven by a force or velocity field is fundamental to modelling many physical processes, including weather forecasting and the simulation of molecular dynamics. High frequency wave energy distributions can also be approximated using flow or transport equations. Applications arise in underwater and room acoustics, vibro-acoustics, seismology, electromagnetics, quantum mechanics and in producing computer generated imagery. In many practical applications, the driving field is not known exactly and the dynamics are determined only up to a degree of uncertainty. This paper presents a boundary integral framework for propagating flows including uncertainties, which is shown to systematically interpolate between a deterministic and a completely random description of the trajectory propagation. A simple but efficient discretisation approach is applied to model uncertain billiard dynamics in an integrable rectangular domain.
Heat transport by laminar boundary layer flow with polymers
Roberto Benzi; Emily S. C. Ching.; Vivien W. S. Chu
2011-04-23
Motivated by recent experimental observations, we consider a steady-state Prandtl-Blasius boundary layer flow with polymers above a slightly heated horizontal plate and study how the heat transport might be affected by the polymers. We discuss how a set of equations can be derived for the problem and how these equations can be solved numerically by an iterative scheme. By carrying out such a scheme, we find that the effect of the polymers is equivalent to producing a space-dependent effective viscosity that first increases from the zero-shear value at the plate then decreases rapidly back to the zero-shear value far from the plate. We further show that such an effective viscosity leads to an enhancement in the drag, which in turn leads to a reduction in heat transport.
On the boundary coupling of topological Landau-Ginzburg models
C. I. Lazaroiu
2003-12-24
I propose a general form for the boundary coupling of B-type topological Landau-Ginzburg models. In particular, I show that the relevant background in the open string sector is a (generally non-Abelian) superconnection of type (0,1) living in a complex superbundle defined on the target space, which I allow to be a non-compact Calabi-Yau manifold. This extends and clarifies previous proposals. Generalizing an argument due to Witten, I show that BRST invariance of the partition function on the worldsheet amounts to the condition that the (0,superconnection's curvature equals a constant endomorphism plus the Landau-Ginzburg potential times the identity section of the underlying superbundle. This provides the target space equations of motion for the open topological model.
Boundary integral formulation for interfacial cracks in thermodiffusive bimaterials
L. Morini; A. Piccolroaz
2015-04-29
An original boundary integral formulation is proposed for the problem of a semi-infinite crack at the interface between two dissimilar elastic materials in the presence of heat flows and mass diffusion. Symmetric and skew-symmetric weight function matrices are used together with a generalized Betti's reciprocity theorem in order to derive a system of integral equations that relate the applied loading, the temperature and mass concentration fields, the heat and mass fluxes on the fracture surfaces and the resulting crack opening. The obtained integral identities can have many relevant applications, such as for the modelling of crack and damage processes at the interface between different components in electrochemical energy devices characterized by multi-layered structures (solid oxide fuel cells and lithium ions batteries).
The boundary effects of the shock wave dispersion in discharges
Markhotok, A.; Popovic, S.; Vuskovic, L.
2008-03-15
Interaction of shock waves with a weakly ionized gas generated by discharges has been studied. An additional thermal mechanism of the shock wave dispersion on the boundary between a neutral gas and discharge has been proposed [A. Markhotok, S. Popovic, and L. Vuskovic, Proceedings of the 15th International Conference on Atomic Processes in Plasmas, March 19-22, 2007 (NIST, Gaitersburg, MD, 2007)]. This mechanism can explain a whole set of thermal features of the shock wave-plasma interaction, including acceleration of the shock wave, broadening or splitting of the deflection signals and its consecutive restoration. Application has been made in the case of a shock wave interacting with a laser induced plasma. The experimental observations support well the results of calculation based on this model.
Boundary and Interface CFTs from the Conformal Bootstrap
F. Gliozzi; P. Liendo; M. Meineri; A. Rago
2015-05-12
We explore some consequences of the crossing symmetry for defect conformal field theories, focusing on codimension one defects like flat boundaries or interfaces. We study surface transitions of the 3d Ising and other O(N) models through numerical solutions to the crossing equations with the method of determinants. In the extraordinary transition, where the low-lying spectrum of the surface operators is known, we use the bootstrap equations to obtain information on the bulk spectrum of the theory. In the ordinary transition the knowledge of the low-lying bulk spectrum allows to calculate the scale dimension of the relevant surface operator, which compares well with known results of two-loop calculations in 3d. Estimates of various OPE coefficients are also obtained. We also analyze in 4-epsilon dimensions the renormalization group interface between the O(N) model and the free theory and check numerically the results in 3d.
An immersed boundary model of the cochlea with parametric forcing
Ko, William
2015-01-01
The cochlea or inner ear has a remarkable ability to amplify sound signals. This is understood to derive at least in part from some active process that magnifies vibrations of the basilar membrane (BM) and the cochlear partition in which it is embedded, to the extent that it overcomes the effect of viscous damping from the surrounding cochlear fluid. Many authors have associated this amplification ability to some type of mechanical resonance within the cochlea, however there is still no consensus regarding the precise cause of amplification. Our work is inspired by experiments showing that the outer hair cells within the cochlear partition change their lengths when stimulated, which can in turn cause periodic distortions of the BM and other structures in the cochlea. This paper investigates a novel fluid-mechanical resonance mechanism that derives from hydrodynamic interactions between an oscillating BM and the surrounding cochlear fluid. We present a model of the cochlea based on the immersed boundary method...
Tachyon condensation in boundary string field theory at one loop
K. Bardakci; A. Konechny
2001-08-21
We compute the one-loop partition function for quadratic tachyon background in open string theory. Both closed and open string representations are developed. Using these representations we study the one-loop divergences in the partition function in the presence of the tachyon background. The divergences due to the open and closed string tachyons are treated by analytic continuation in the tachyon mass squared. We pay particular attention to the imaginary part of the analytically continued expressions. The last one gives the decay rate of the unstable vacuum. The dilaton tadpole is also given some partial consideration. The partition function is further used to study corrections to tachyon condensation processes describing brane descent relations. Assuming the boundary string field theory prescription for construction of the string field action via partition function holds at one loop level we study the one-loop corrections to the tachyon potential and to the tensions of lower-dimensional branes.
Aerodynamic Models for Hurricanes III. Modeling hurricane boundary layer
Leonov, Arkady I
2008-01-01
The third paper of the series (see previous ones in Refs.[1-2]) discusses basic physicalprocesses in the (quasi-) steady hurricane boundary layer (HBL), develops an approximate airflow model, establishes the HBL structure, and presents integral balance relations for dynamic and thermodynamic variables in HBL. Models of evaporation and condensation are developed, where the condensation is treated similarly to the slow combustion theory. A turbulent approximation for the lower sub-layer of HBL is applied to the sea-air interaction to establish the observed increase in angular momentum in the outer region of HBL.A closed set of balance relations has been obtained. Simple analytical solution of the set yields expressions for the basic dynamic variables - maximal tangential and radial velocities in hurricane, maximal vertical speed in eye wall, the affinity speed of hurricane travel, and the maximal temperature increase after condensation. Estimated values of the variables seem to be realistic. An attempt is also ...
The growth mechanism of grain boundary carbide in Alloy 690
Li, Hui; Xia, Shuang; Zhou, Bangxin; Peng, Jianchao
2013-07-15
The growth mechanism of grain boundary M{sub 23}C{sub 6} carbides in nickel base Alloy 690 after aging at 715 °C was investigated by high resolution transmission electron microscopy. The grain boundary carbides have coherent orientation relationship with only one side of the matrix. The incoherent phase interface between M{sub 23}C{sub 6} and matrix was curved, and did not lie on any specific crystal plane. The M{sub 23}C{sub 6} carbide transforms from the matrix phase directly at the incoherent interface. The flat coherent phase interface generally lies on low index crystal planes, such as (011) and (111) planes. The M{sub 23}C{sub 6} carbide transforms from a transition phase found at curved coherent phase interface. The transition phase has a complex hexagonal crystal structure, and has coherent orientation relationship with matrix and M{sub 23}C{sub 6}: (111){sub matrix}//(0001){sub transition}//(111){sub carbide}, <112{sup ¯}>{sub matrix}//<21{sup ¯}10>{sub transition}//<112{sup ¯}>{sub carbide}. The crystal lattice constants of transition phase are c{sub transition}=?(3)×a{sub matrix} and a{sub transition}=?(6)/2×a{sub matrix}. Based on the experimental results, the growth mechanism of M{sub 23}C{sub 6} and the formation mechanism of transition phase are discussed. - Highlights: • A transition phase was observed at the coherent interfaces of M{sub 23}C{sub 6} and matrix. • The transition phase has hexagonal structure, and is coherent with matrix and M{sub 23}C{sub 6}. • The M{sub 23}C{sub 6} transforms from the matrix directly at the incoherent phase interface.
Hybrid immersed interface-immersed boundary methods for AC dielectrophoresis
Hossan, Mohammad Robiul [School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920 (United States); Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK 73034-5209 (United States); Dillon, Robert [Department of Mathematics, Washington State University, Pullman, WA 99164-3113 (United States); Dutta, Prashanta, E-mail: dutta@mail.wsu.edu [School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920 (United States)
2014-08-01
Dielectrophoresis, a nonlinear electrokinetic transport mechanism, has become popular in many engineering applications including manipulation, characterization and actuation of biomaterials, particles and biological cells. In this paper, we present a hybrid immersed interface–immersed boundary method to study AC dielectrophoresis where an algorithm is developed to solve the complex Poisson equation using a real variable formulation. An immersed interface method is employed to obtain the AC electric field in a fluid media with suspended particles and an immersed boundary method is used for the fluid equations and particle transport. The convergence of the proposed algorithm as well as validation of the hybrid scheme with experimental results is presented. In this paper, the Maxwell stress tensor is used to calculate the dielectrophoretic force acting on particles by considering the physical effect of particles in the computational domain. Thus, this study eliminates the approximations used in point dipole methods for calculating dielectrophoretic force. A comparative study between Maxwell stress tensor and point dipole methods for computing dielectrophoretic forces are presented. The hybrid method is used to investigate the physics of dielectrophoresis in microfluidic devices using an AC electric field. The numerical results show that with proper design and appropriate selection of applied potential and frequency, global electric field minima can be obtained to facilitate multiple particle trapping by exploiting the mechanism of negative dielectrophoresis. Our numerical results also show that electrically neutral particles form a chain parallel to the applied electric field irrespective of their initial orientation when an AC electric field is applied. This proposed hybrid numerical scheme will help to better understand dielectrophoresis and to design and optimize microfluidic devices.
Boundary Value Methods for the Numerical Approximation of Ordinary Differential Equations
Brugnano, Luigi
of a discrete BVP. This approach defines a BVM with (kl, k2)-boundary conditions. Observe that, for kl = k and
Shells on a Sphere: Tectonic Plate Motion and Plate Boundary Deformation
Apel, Edwin Victor
2011-01-01
plate boundary deformation of Sakhalin from geodetic data,a pole located north of Sakhalin. The modeled AMU plateis sparse and diffuse. Sakhalin Island exhibits large
ORNL materials researchers get first look at atom-thin boundaries...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of the electronic behaviors of a one-dimensional boundary separating atom-thin graphene and hexagonal boron nitride materials. Scientists at the Oak Ridge National...
On the pointwise jump condition at the free boundary in the 1-phase ...
2004-02-09
Brasil. Mat. (N. S. ) 32 (2001), no. 3,. 401-433. [Da] D. Danielli, A singular perturbation approach to a two phase parabolic free boundary problem arising in
Surface relief produced by diffusion induced boundary migration in Cu-Zn
Tsai, Y.S.; Meyrick, G.; Shewmon, P.G.
1984-03-01
Experimental observations are presented that demonstrate that diffusion induced grain boundary migration in copper foils exposed to zinc vapor, from a Cu-15 pct Zn alloy, can be studied directl after treatment without etching. The general characteristics of migration are in accord with previous investigations, but novel changes in the surface topography are described. Pits were formed on the surface of areas swept by boundary migration; also, the surface was often converted into a series of corrugations. The formation of pits suggests that the grain boundary diffusivity of zinc exceeds that of copper. The corrugations are believed to indicate that boundaries sometimes move in an intermittent manner.
Pekker, Leonid
2015-01-01
In this paper we propose new boundary conditions at the hot walls with thermionic electron emission for two-temperature thermal arc models. In the derived boundary conditions the walls are assumed to be made from refractory metals and that the erosion of the wall is small and, therefore, is not taken into account in the model. In these boundary conditions the plasma sheath formed at the electrode is considered as the interface between the plasma and the wall. The derived boundary conditions allow the calculation of the heat flux to the walls from the plasma and consequently the thermionic electron current that makes the two temperature thermal model self consistent.
The Inner Boundary Condition for a Thin Disk Accreting Into a Black Hole
B. Paczy?ski
2000-04-10
Contrary to some recent claims the `no torque inner boundary condition' as applied at the marginally stable orbit is correct for geometrically thin disks accreting into black holes.
Grain Boundary Percolation Modeling of Fission Gas Release in Oxide Fuels
Paul C. Millett; Michael R. Tonks; S. B. Biner
2012-05-01
We present a new approach to fission gas release modeling in oxide fuels based on grain boundary network percolation. The method accounts for variability in the bubble growth and coalescence rates on individual grain boundaries, and the resulting effect on macroscopic fission gas release. Two-dimensional representa- tions of fuel pellet microstructures are considered, and the resulting gas release rates are compared with traditional two-stage Booth models, which do not account for long-range percolation on grain boundary net- works. The results show that the requirement of percolation of saturated grain boundaries can considerably reduce the total gas release rates, particularly when gas resolution is considered.
Ho Tat Lam; Yue Yu; Kwok Yip Szeto
2015-08-30
The topological phases in one-dimensional quantum walk can be classified by the coin parameters. By solving for the general exact solutions of bound states in one-dimensional quantum walk with boundaries specified by different coin parameters, we show that these bound states are Majorana modes with quasi-energy $E=0,\\pi$. These modes are qualitatively different for different boundary conditions used. For two-boundary system with symmetric boundary conditions, the interaction energy between two Majorana bound states can be computed, as in the case of a finite wire. Suggestion of observing these modes are provided.
Primary, secondary instabilities and control of the rotating-disk boundary layer
;Typical 3D boundary layers rotating disk swept wing Common features: · crossflow component near the wall · inflection point · strong inviscid instability · secondary instabilities ; growth and saturation of crossflow
Grain boundary chemistry effects on environment-induced crack growth of iron-based alloys
Jones, R.H.
1992-11-01
Relation between grain boundary chemistry and environment-induced crack growth of Fe-based alloys is reviewed. The importance of the cleanliness of steels is clearly demonstrated by direct relations between grain boundary chemistry and crack growth behavior for both H and anodic dissolution-induced crack growth. Relationships between strain to failure, work of fracture, K[sub ISCC], crack velocity and fracture mode and grain boundary chemistry are presented. Only results in which the grain boundary chemistry has been measured directly by Auger electron spectroscopy (AES) on intergranular surfaces exposed by in situ fracture have been considered in this review.
Grain boundary chemistry effects on environment-induced crack growth of iron-based alloys
Jones, R.H.
1992-11-01
Relation between grain boundary chemistry and environment-induced crack growth of Fe-based alloys is reviewed. The importance of the cleanliness of steels is clearly demonstrated by direct relations between grain boundary chemistry and crack growth behavior for both H and anodic dissolution-induced crack growth. Relationships between strain to failure, work of fracture, K{sub ISCC}, crack velocity and fracture mode and grain boundary chemistry are presented. Only results in which the grain boundary chemistry has been measured directly by Auger electron spectroscopy (AES) on intergranular surfaces exposed by in situ fracture have been considered in this review.
Boundary conditions for the Einstein-Christoffel formulation of Einstein's equations
Douglas N. Arnold; Nicolae Tarfulea
2006-11-02
Specifying boundary conditions continues to be a challenge in numerical relativity in order to obtain a long time convergent numerical simulation of Einstein's equations in domains with artificial boundaries. In this paper, we address this problem for the Einstein--Christoffel (EC) symmetric hyperbolic formulation of Einstein's equations linearized around flat spacetime. First, we prescribe simple boundary conditions that make the problem well posed and preserve the constraints. Next, we indicate boundary conditions for a system that extends the linearized EC system by including the momentum constraints and whose solution solves Einstein's equations in a bounded domain.
Liu, Tingguang; Xia, Shuang; Li, Hui; Zhou, Bangxin; Bai, Qin
2014-05-01
Grain boundary engineering was carried out on an aging-treated nickel based Alloy 690, which has precipitated carbides at grain boundaries. Electron backscatter diffraction technique was used to investigate the grain boundary networks. Results show that, compared with the solution-annealed samples, the aging-treated samples with pre-existing carbides at grain boundaries need longer duration or higher temperature during annealing after low-strain tensile deformation for forming high proportion of low-? coincidence site lattice grain boundaries (more than 75%). The reason is that the primary recrystallization is inhibited or retarded owing to that the pre-existing carbides are barriers to grain boundaries migration. - Highlights: • Study of GBE as function of pre-existing GB carbides, tensile strain and annealing • Recrystallization of GBE is inhibited or retarded by the pre-existing carbides. • Retained carbides after annealing show the original GB positions. • More than 80% of special GBs were formed after the modification of GBE processing. • Multiple twinning during recrystallization is the key process of GBE.
California at Berkeley, University of
Mycological Society of America A Gene Genealogical Approach to Recognize Phylogenetic Species-8897 A gene genealogical approach to recognize phylogenetic species boundaries in the lichenized fungus, was investigated as a model system in which to recognize species boundaries. Gene genealogies of 6 and 12 loci were
Control of the ocean circulation by boundaries and topography P.B. Rhines
energy in the ocean circulation is dominated by boundary currents, zonal jets and mesoscale eddies and jet-like zonal currents dominate the kinetic energy of the world ocean. They are key features of bothControl of the ocean circulation by boundaries and topography P.B. Rhines University of Washington
Spreading of the Free Boundary of an Ideal Fluid in a Vacuum
Bigelow, Stephen
Spreading of the Free Boundary of an Ideal Fluid in a Vacuum Thomas C. Sideris Department by an ideal fluid surrounded by vacuum will be shown to grow linearly in time provided the pressure an ideal fluid occupying a bounded region in space surrounded by vacuum. The boundary of this region
Role of lubricin and boundary lubrication in the prevention of chondrocyte apoptosis
Role of lubricin and boundary lubrication in the prevention of chondrocyte apoptosis Kimberly A, a mucinous glyco- protein encoded by the PRG4 gene, provides boundary lubrication in articular joints. Joint. In the bovine explant system, the addition of lubricin as a test lubricant signifi- cantly lowered the static
Modification of boundary lubrication by oil-soluble friction modifier Yingxi Zhua
Granick, Steve
Modification of boundary lubrication by oil-soluble friction modifier additives Yingxi Zhua in lubricants of the type used at the wet clutch interface in automatic transmissions has been studied using in the boundary lubrication regime and compared to a fully-formulated automatic transmission fluid (ATF). 1
Gas-surface interaction and boundary conditions for the Boltzmann equation
Mieussens, Luc
Gas-surface interaction and boundary conditions for the Boltzmann equation St´ephane Brull, Pierre Equation. The interaction between the wall atoms and the gas molecules within a thin surface layer of the gas in the bulk flow. Boundary conditions are formally derived from this model by using classical
THE BOUNDARY RIGIDITY PROBLEM IN THE PRESENCE OF A MAGNETIC FIELD
Uhlmann, Gunther
of reversible systems 36 6.4. Generic local boundary rigidity 38 Appendix A. Geometry of magnetic systems 42 A.1. SantalÂ´o's formula 45 A.5. Index form of a magnetic geodesic 46 Appendix B. Study of a certain classTHE BOUNDARY RIGIDITY PROBLEM IN THE PRESENCE OF A MAGNETIC FIELD NURLAN S. DAIRBEKOV, GABRIEL P
Boundary uniqueness theorems for functions whose integrals over hyperbolic discs vanish
Ochakovskaya, Oksana A
2013-02-28
Sharp conditions are found describing the admissible rate of decrease of a nontrivial function whose integrals over all hyperbolic discs with fixed radius vanish. For the first time, the boundary behaviour of the function is investigated in a neighbourhood of a single point on the boundary of the domain of definition. Bibliography: 17 titles.
Boettcher, Markus
1 Magnetic Field Generation and Particle Energization at Relativistic Shear Boundaries+e) plasmas. We find efficient magnetic field generation and particle energization at the shear boundary generation (Colgate et al 2001, Medvedev & Loeb 1999) and nonthermal particle energization (Berezhko 1981
A New Look at the High Frequency Boundary Element and Rayleigh Integral Approximations
Seybert, Andrew F.
03NVC-114 A New Look at the High Frequency Boundary Element and Rayleigh Integral Approximations D of Automotive Engineers, Inc. ABSTRACT This paper revisits the popular Rayleigh integral approximation, and also to the Rayleigh integral. Both methods are approximations to the boundary integral equation, and can solve
Monneau, Régis
On the regularity of a free boundary for a nonlinear obstacle problem arising in superconductor of superconductivity. We consider solutions in a Lipschitz bounded open set and prove the regularity of the free-Landau theory for a superconductor with a density of vortices in an interior region whose boundary is a free
Geerts, Bart
Boundary Layer Energy Transport and Cumulus Development over a Heated Mountain: An Observational an isolated, heated mountain are presented. The data were collected around the Santa Catalina Mountains congestus to cumulonimbus development over the mountain. Flights in the boundary layer around the mountain
Thermal convection with a freely moving top boundary Jin-Qiang Zhong
Zhang, Jun
Thermal convection with a freely moving top boundary Jin-Qiang Zhong Department of Physics, New; accepted 29 September 2005; published online 22 November 2005 In thermal convection, coherent flow-organization. They range from small-scale thermal plumes that are produced near both the top and the bottom boundaries
A 3 km atmospheric boundary layer on Titan indicated by dune spacing and Huygens data
Claudin, Philippe
Note A 3 km atmospheric boundary layer on Titan indicated by dune spacing and Huygens data Ralph D a b s t r a c t Some 20% of Titan's surface is covered in large linear dunes that resemble parameter limiting the growth of giant dunes, namely the boundary layer thickness (Andreotti et al., 2009
to test the strengths and limitations of cloud boundary retrievals from radiosonde profiles, 4 yearsComparison between active sensor and radiosonde cloud boundaries over the ARM Southern Great Plains radiosonde-based methods applied to 200 m resolution profiles obtained at the same site. The lidar
Direct Forcing Immersed Boundary Methods: Finite Element Versus Finite Volume Approach
Frisani, Angelo 1980-
2012-12-07
immersed boundary methods are in good agreement with the predictions from STAR-CCM+ and the numerical data from the other IBMs. The immersed boundary method based of finite element approach is numerically more accurate than the IBM based on finite volume...
Delineating Boundaries for Imprecise Regions Iris Reinbacher Marc Benkert Marc van Kreveld
Mitchell, Joseph S.B.
Delineating Boundaries for Imprecise Regions Iris Reinbacher Marc Benkert Marc van Kreveld Joseph S, minimum-perimeter polygons Corresponding Author: Marc van Kreveld Universiteit Utrecht Department: +31 (30) 251 3791 Email: marc@cs.uu.nl 1 #12;Delineating Boundaries for Imprecise Regions Iris
Mitrea, Marius
Spectral properties of parabolic layer potentials and transmission boundary problems in nonsmooth, and is a Lipschitz domain. Applications to transmission boundary value problems are also presented. 1 Introduction. While, in principle, this seems flexible enough a program to be worth pursuing in the case of the heat
Mitrea, Marius
Spectral properties of parabolic layer potentials and transmission boundary problems in nonsmooth# is a Lipschitz domain. Applications to transmission boundary value problems are also presented. 1 Introduction of the heat operator, the algebra associated with the problem at hand is di#erent. In particular
Hofmann, Steve
Spectral properties of parabolic layer potentials and transmission boundary problems in nonsmooth potential operator, and is a Lipschitz domain. Applications to transmission boundary value problems in the case of the heat operator, the algebra associated with the problem at hand is di#11;erent
April 22, 2010 Coronal hole boundaries evolution at small scales: II. XRT view
April 22, 2010 Coronal hole boundaries evolution at small scales: II. XRT view Can small-scale outflows at CHBs be a source of the slow solar wind? S. Subramanian, M. S. Madjarska and J. G. Doyle Armagh to further explore the small-scale evolution of coronal hole boundaries using X-ray high-resolution and high
Numerische Methoden 1 B.J.P. Kaus 4 Fun with boundary conditions
Kaus, Boris
= c1 (6) at i = nx, the boundary condition is given by Tn+1 nx+1 - Tn+1 nx-1 2x = c2 (7) 1 #12 that are not part of the numerical grid (Tn+1 0 and Tn+1 nx+1). These points are called fictious boundary points
Boundary migration in Zn bicrystal induced by a high magnetic field A. D. Sheikh-Alia)
Garmestani, Hamid
Boundary migration in Zn bicrystal induced by a high magnetic field A. D. Sheikh-Alia) National migrated under the action of a magnetic driving force in the direction of the grain with higher diamagnetic.1063/1.1572536 Magnetically induced grain boundary migration has been established for diamagnetic bismuth13 and zinc.4
A fast multipole boundary element method for solving the thin plate bending problem
Liu, Yijun
in this paper. The method is based on the Kirchhoff thin plate bending theory and the biharmonic equationA fast multipole boundary element method for solving the thin plate bending problem S. Huang, Y: Fast multipole method Boundary element method Thin plate bending problem a b s t r a c t A fast
Wrigstad, Tobias
Using ownership types to support library aliasing boundaries Luke Wagner Jaakko J¨arvi Bjarne types. Based on the positive experience with the concurrency library, this paper considers a family of the aliasing boundaries required by the library with those expressed with own- ership types; (3) describes
On the moving boundary conditions for a hydraulic fracture Emmanuel Detournay a,b,
Peirce, Anthony
On the moving boundary conditions for a hydraulic fracture Emmanuel Detournay a,b, , Anthony Peirce 2014 Keywords: Hydraulic fractures Speed equation Ill-posedness a b s t r a c t This paper re-examines the boundary conditions at the moving front of a hydraulic fracture when the fluid front has coalesced
Ill-Conditioning versus Ill-Posedness for the Boundary Controllability of the Heat
Paris-Sud XI, Université de
Ill-Conditioning versus Ill-Posedness for the Boundary Controllability of the Heat Equation. Faker controllability problems of the heat equa- tion where the control variable is a boundary Dirichlet data. We focus-conditioning are features users have to deal with appropriately in the controllability of diffusion problems for se- cure
Stress-driven migration of simple low-angle mixed grain boundaries , M. Haataja a,
Cai, Wei
Stress-driven migration of simple low-angle mixed grain boundaries A.T. Lim a , M. Haataja a, , W investigated the stress-induced migration of a class of simple low-angle mixed grain boundaries (LAMGBs) using under an externally applied stress can occur by dislocation glide, and was observed to be coupled
Milan Batista
2015-08-18
The purpose of this paper is the extension of Jacobi's criteria for positive definiteness of second variation of the simplest problems of calculus of variations subject to mixed boundary conditions. Both non constrained and isoperimetric problems are discussed. The main result is that Jacobi's condition remains valid also for the mixed boundary conditions.
Milan Batista
2015-06-24
The purpose of this paper is the extension of Jacobi's criteria for positive definiteness of second variation of the simplest problems of calculus of variations subject to mixed boundary conditions. Both non constrained and isoperimetric problems are discussed. The main result is that Jacobi's condition remains valid also for the mixed boundary conditions.
Modeling a swimming fish with an initial-boundary value problem: unsteady maneuvers of an elastic
Smith, Marc L.
Modeling a swimming fish with an initial-boundary value problem: unsteady maneuvers of an elastic In order to model unsteady maneuvers in swimming fish, we develop an initial-boundary value problem for a fourth-order hyperbolic partial differential equation in which the fish's body is treated as an inhomo
Three-dimensional grain boundary spectroscopy in transparent high power ceramic laser
Byer, Robert L.
Three-dimensional grain boundary spectroscopy in transparent high power ceramic laser materials across grain boundaries (GBs) in Nd3+ :YAG laser ceramics. It is clearly shown that Nd3+ segregation point the way to further improvements in what is already an impressive class of ceramic laser materials
Two-Point Boundary Value Problems for Curves: The Case of Minimum Free Energy Paths
Skeel, Robert
Two-Point Boundary Value Problems for Curves: The Case of Minimum Free Energy Paths corrected.S.A. Abstract The calculation of a minimum free energy path can be considered as a two-point boundary value box solvers. The second paragraph of Section 1 is corrected. Because free energy is defined in terms
Modeling open boundaries in dissipative MHD simulation E.T. Meier a,
of large physical domains to concentrate computational resources is neces- sary or desirable in simulating many natural and man-made plasma phenomena. Three open boundary condition (BC) methods for such domain. LOBC, based on manipulating Calderon-type near-boundary sources, essentially damp hyperbolic effects
THE SPIN-COATING PROCESS: ANALYSIS OF THE FREE BOUNDARY VALUE PROBLEM
Saal, JÃ¼rgen
THE SPIN-COATING PROCESS: ANALYSIS OF THE FREE BOUNDARY VALUE PROBLEM ROBERT DENK, MATTHIAS of the spin-coating process is presented and investigated from the analytical point of view. More precisely, the spin-coating process is being described as a one-phase free boundary value problem for Newtonian fluids
Interfacial stress analysis for multi-coating systems using an advanced boundary element method
Liu, Yijun
Interfacial stress analysis for multi-coating systems using an advanced boundary element method J for multi-coating systems using an advanced boundary element method (BEM) developed earlier in [Luo JF, Liu by the analytical solution of a special multi-coating problem. Detailed in- terfacial stress analysis for a two
STABILIZED FINITE ELEMENT METHODS FOR FLOWS WITH MOVING BOUNDARIES AND INTERFACES
Tezduyar, Tayfun E.
1 STABILIZED FINITE ELEMENT METHODS FOR FLOWS WITH MOVING BOUNDARIES AND INTERFACES Tayfun E boundaries and interfaces. The methods developed can be classified into two main categories: interface-tracking and interface-capturing techniques. Both classes of techniques are based on sta- bilized formulations
STABILIZED FINITE ELEMENT METHODS FOR COMPUTATION OF FLOWS WITH MOVING BOUNDARIES AND INTERFACES
Tezduyar, Tayfun E.
1 STABILIZED FINITE ELEMENT METHODS FOR COMPUTATION OF FLOWS WITH MOVING BOUNDARIES AND INTERFACES of flow problems with moving boundaries and interfaces. The methods developed are categorized into two classes: interface-tracking and interface-capturing techniques. Both classes of techniques are based
Stability analysis of twist grain boundaries in lamellar phases of block copolymers
Xusheng Zhang; Zhi-Feng Huang; Jorge Viñals
2008-04-13
Twist grain boundaries are widely observed in lamellar phases of block copolymers. A mesoscopic model of the copolymer is used to obtain stationary configurations that include a twist grain boundary, and to analyze their stability against long wavelength perturbations. The analysis presented is valid in the weak segregation regime, and includes direct numerical solution of the governing equations as well as a multiple scale analysis. We find that a twist boundary configuration with arbitrary misorientation angle can be well described by two modes, and obtain the equations for their slowly varying amplitudes. The width of the boundary region is seen to scale as $\\epsilon^{-1/4}$, with $\\epsilon$ being the dimensionless distance to the order-disorder transition. We finally present the results of the linear stability analysis of the planar boundary.
Implementation of the Immersed Boundary Method in the Weather Research and Forecasting model
Lundquist, K A
2006-12-07
Accurate simulations of atmospheric boundary layer flow are vital for predicting dispersion of contaminant releases, particularly in densely populated urban regions where first responders must react within minutes and the consequences of forecast errors are potentially disastrous. Current mesoscale models do not account for urban effects, and conversely urban scale models do not account for mesoscale weather features or atmospheric physics. The ultimate goal of this research is to develop and implement an immersed boundary method (IBM) along with a surface roughness parameterization into the mesoscale Weather Research and Forecasting (WRF) model. IBM will be used in WRF to represent the complex boundary conditions imposed by urban landscapes, while still including forcing from regional weather patterns and atmospheric physics. This document details preliminary results of this research, including the details of three distinct implementations of the immersed boundary method. Results for the three methods are presented for the case of a rotation influenced neutral atmospheric boundary layer over flat terrain.
Further development and testing of a second-order bulk boundary layer model. Master's thesis
Krasner, R.D.
1993-05-03
A one-layer bulk boundary layer model is developed. The model predicts the mixed layer values of the potential temperature, mixing ratio, and u- and v-momentum. The model also predicts the depth of the boundary layer and the vertically integrated turbulence kinetic energy (TKE). The TKE is determined using a second-order closure that relates the rate of dissipation to the TKE. The fractional area covered by rising motion sigma and the entrainment rate (E) are diagnostically determined. The model is used to study the clear convective boundary layer (CBL) using data from the Wangara, Australia boundary layer experiment. The Wangara data is also used as an observation base to validate model results. A further study is accomplished by simulating the planetary boundary layer (PBL) over an ocean surface. This study is designed to find the steady-state solutions of the prognostic variable.
The thermodynamic cost of driving quantum systems by their boundaries
Felipe Barra
2015-10-22
The laws of thermodynamics put limits to the efficiencies of thermal machines. Analogues of these laws are now established for quantum engines weakly and passively coupled to the environment providing a framework to find improvements to their performance. Systems whose interaction with the environment is actively controlled do not fall in that framework. Here we consider systems actively and locally coupled to the environment, evolving with a so-called boundary-driven Lindblad equation. Starting from a unitary description of the system plus the environment we simultaneously obtain the Lindblad equation and the appropriate expressions for heat, work and entropy-production of the system extending the framework for the analysis of new, and some already proposed, quantum heat engines. We illustrate our findings in spin 1/2 chains and explain why an XX chain coupled in this way to a single heat bath relaxes to thermodynamic-equilibrium while and XY chain does not. Additionally, we show that an XX chain coupled to a left and a right heat baths behaves as a quantum engine, a heater or refrigerator depending on the parameters, with efficiencies bounded by Carnot efficiencies.
Wave mediated angular momentum transport in astrophysical boundary layers
Hertfelder, Marius
2015-01-01
Context. Disk accretion onto weakly magnetized stars leads to the formation of a boundary layer (BL) where the gas loses its excess kinetic energy and settles onto the star. There are still many open questions concerning the BL, for instance the transport of angular momentum (AM) or the vertical structure. Aims. It is the aim of this work to investigate the AM transport in the BL where the magneto-rotational instability (MRI) is not operating owing to the increasing angular velocity $\\Omega(r)$ with radius. We will therefore search for an appropriate mechanism and examine its efficiency and implications. Methods. We perform 2D numerical hydrodynamical simulations in a cylindrical coordinate system $(r, \\varphi)$ for a thin, vertically inte- grated accretion disk around a young star. We employ a realistic equation of state and include both cooling from the disk surfaces and radiation transport in radial and azimuthal direction. The viscosity in the disk is treated by the {\\alpha}-model; in the BL there is no v...
Fermionic Casimir Effect on the Topological Insulator Boundary
Muniz, C R
2014-01-01
In this paper we study the Casimir effect on the conducting surface of a topological insulator characterized by both $Z_2$ topological index and time reversal symmetry, subject to the action of a static and spatially homogeneous magnetic field perpendicular to that surface, at zero temperature. To do this, we consider modifications in the Gauss' law that arise due to the nonzero gradient of the axion-like pseudoscalar factor coupled to the constant magnetic field, which occur in a term that must be added to the electromagnetic Lagrangian in order to account for the topological properties of the system. Such term allows to find an effective point-like charge that changes the quantum vacuum of a spinor field in 1+2 dimensions confined on the edge under analysis. Since that the Casimir energy found depends on a length defined on the boundary, we show that there is a tangential density of force or a shear stress associated to the surface, tending to shrink or stretch it depending on the magnetic field direction. ...
Computer simulation of grain boundary self-diffusion in aluminum
Dragunov, Andrei S., E-mail: andrei.dragunov@aun.edu.ng [American University of Nigeria, Nigeria, Adamawa State, Yola Yola By-Pass 98 Lamido Zubairu Way (Nigeria); Weckman, A. V.; Demyanov, B. F. [Altai State Technical University, Russia, Altai Region, Barnaul (Russian Federation)
2014-10-06
In the work study the process of self-diffusion in symmetric tilt grain boundaries (GB) with the axes misorientation [100], [110] and [111]. The research was carried out by the methods of computer simulation The objects of the research are the three GB of common and special type for each axis misorientation. The angles of misorientation of the common GB is amounted to 10°, 30° and 50°. The simulation was performed by the method of molecular dynamics in the temperature range from 600 to 1000 K, with an interval of 50 K. For research on the direction jumps atoms were built tracks the movement of atoms in the process of self-diffusion. The calculations have shown, that for all of GB is characterized by pronounced anisotropy of the jumps at low temperatures (< 700K). At temperatures near to the melting point directions of the jumps are isotropic only for three GB (?=30°[100], ?=50=[100] and ?5(013)[100]). For other GB such as [100] and [110] remains priority direction of diffusion along the nuclei GB dislocations. Arrenius curves have from one to three linear plots with different tilt. Change the tilt of Arrenius dependences testifies to the change in the mechanism of self-diffusion. The parameters of grainboundary self-diffusion were determined The activation energy of grainboundary diffusion in 4–5 times lower than the energy of activation of a volume self-diffusion of aluminum (about 200 KJ/mol). The minimum value of activation energy has GB 10° with the axis misorientation [100] (10,15 KJ/mol), maximum (104.12 Kj/mol) - a special GB ?11(113)
Erlebacher, Gordon
Active Control of Instabilities in Laminar BoundaryLayer Flow -- Part II: Use of Sensors growth and stabilize the instabilities within the laminar boundary layer. This scenario is shown in Fig
Giron, Marie Minh-Thu
2013-01-01
Records of ocean biogeochemistry in marine sediments show shifts across the Cretaceous-Paleogene boundary (K-Pg) that are simultaneous with the extinction event and onset of the boundary clay deposition. However, the ...
Read, Robert Kevin
1997-01-01
The unsteady boundary layer behavior on the concave surface of a curved plate is investigated. Detailed experimental investigations are carried out to study the effect of unsteady wakes on the boundary layer transition under varying wake passing...
Strauss, H. R.
2014-09-15
A response is given to “Comment on ‘Velocity boundary conditions at a tokamak resistive wall’?” [Phys. Plasmas 21, 094701 (2014)].
Ion boundary conditions in semi-infinite fluid models of electron beam-plasma interaction
Levko, Dmitry [LAPLACE (Laboratoire Plasma et Conversion d'Energie), Universite de Toulouse, UPS, INPT Toulouse, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France)
2014-10-15
The modified Bohm criterion is derived for the plasma consisting of the monoenergetic electron beam and thermal electrons. This criterion allows us to define the accurate ion boundary conditions for semi-infinite collisionless fluid models of electron beam–plasma interaction. In the absence of electron beam, these boundary conditions give the classical sheath parameters. When the monoenergetic electron beam propagates through the plasma, the fluid model with proposed boundary conditions gives the results, which are in qualitative agreement with the results obtained earlier in M. Sharifian and B. Shokri, Phys. Plasmas 14, 093503 (2007). However, dynamics and parameters of the plasma sheath are different.
Ramos, I C
2015-01-01
We present the adaptation to non--free boundary conditions of a pseudospectral method based on the (complex) Fourier transform. The method is applied to the numerical integration of the Oberbeck--Boussinesq equations in a Rayleigh--B\\'enard cell with no-slip boundary conditions for velocity and Dirichlet boundary conditions for temperature. We show the first results of a 2D numerical simulation of dry air convection at high Rayleigh number ($R\\sim10^9$). These results are the basis for the later study, by the same method, of wet convection in a solar still.
Terwilliger, C.D.; Chiang, Y.M. (Massachusetts Inst. of Tech., Cambridge, MA (USA)); Eastman, J.A.; Liao, Y. (Argonne National Lab., IL (USA))
1991-06-01
This work explores the use of high temperature differential scanning calorimetry as a novel way in which to measure thermodynamic and kinetic properties of grain boundaries in ceramics. A calorimetric study of grain growth has become practical only recently, with the development of processing methods for nanocrystalline materials (10--50 nm grain size) that have enough grain boundary area and thus grain boundary excess properties to be detected by commercial calorimeters. Here we report results from experiments on nanocrystalline silicon and titanium dioxide. 14 refs., 6 figs.
Boundary Effects on Bose-Einstein Condensation in Ultra-Static Space-Times
L. Akant; E. Ertugrul; Y. Gul; O. T. Turgut
2015-05-13
The boundary effects on the Bose-Einstein condensation of a Bose gas with a nonvanishing chemical potential on an ultra-static space-time are studied. High temperature regime, which is the relevant regime for the relativistic gas, is studied through the heat kernel expansion for both Dirichlet and Neumann boundary conditions. The high temperature expansion in the presence of a chemical potential is generated via the Mellin transform methods as applied to the harmonic sums representing the free energy and the depletion coefficient. The effects of boundary conditions on the relation between depletion coefficient and temperature are analyzed. The analysis is done for both charged and neutral bosons.
Introduction to Mathematical Physics. Calculus of Variations and Boundary-value Problems
V. M. Adamyan; M. Ya. Sushko
2015-03-05
This book considers posing and the methods of solving simple linear boundary-value problems in classical mathematical physics. The questions encompassed include: the fundamentals of calculus of variations; one-dimensional boundary-value problems in the oscillation and heat conduction theories, with a detailed analysis of the Sturm-Liouville boundary-value problem and substantiation of the Fourier method; sample solutions of the corresponding problems in two and three dimensions, with essential elements of the special function theory. The text is designed for Physics, Engineering, and Mathematics majors.
Rohrer, Gregory S.
Characterization of the Grain-Boundary Character and Energy Distributions of Yttria Using Automated (GBCD) and grain-boundary energy distribution (GBED). The GBCD de- rived from the three-dimensional data- entation parameters.10 In parallel with the GBCD, one can define the grain-boundary energy distribution
Rohrer, Gregory S.
The five-parameter grain boundary character and energy distributions of a fully austenitic high sectioning. The relative grain boundary area and energy distributions were strongly influenced by both structure (e.g. face- centered cubic) have very similar grain boundary character and energy distributions. Ó
Athens, University of
Robust model-based detection of the lung field boundaries in portable chest radiographs supported of the lung field boundaries in portable chest radiographs supported by selective thresholding D K Iakovidis1-ray misinterpretation rates. This paper presents a novel methodology for the detection of the lung field boundaries
Effective slip boundary conditions for arbitrary periodic surfaces: the surface mobility tensor
Kamrin, Kenneth N.
In a variety of applications, most notably microfluidics design, slip-based boundary conditions have been sought to characterize fluid flow over patterned surfaces. We focus on laminar shear flows over surfaces with periodic ...
Boundary lubrication of articular cartilage : contribution of hyaluronan in health and injury
Antonacci, Jennifer M.
2011-01-01
ability to act as boundary lubricants. Ann Rheum Dis 43:641-of the cartilage and lubricant. Arthritis Rheum 11:674-82,viscous, elastic and lubricant properties. J Phys 119:244-
Interannual variability of the Pacific water boundary current in the Beaufort Sea
Brugler, Eric T
2013-01-01
Between 2002 and 2011 a single mooring was maintained in the core of the Pacific Water boundary current in the Alaskan Beaufort Sea near 152° W. Using velocity and hydrographic data from six year-long deployments during ...
Zhang, Wenxia
2015-03-02
and hypoxia formation. In this research, Both observations and numerical models are used to study models' ability of reproducing observed stratification and bottom boundary layer dynamics over the Texas-Louisiana shelf. Simulated vertical stratification...
Analysis and interpretation of tidal currents in the coastal boundary layer
May, Paul Wesley, 1950-
1979-01-01
Concern with the impact of human activities on the coastal region of the world's oceans has elicited interest in the so-called "coastal boundary layer"-that band of water adjacent to the coast where ocean currents adjust ...
Dynamics on the Laminar-Turbulent Boundary and the Origin of the Maximum Drag Reduction Asymptote
Graham, Michael D.
Dynamical trajectories on the boundary in state space between laminar and turbulent plane channel flow—edge states—are computed for Newtonian and viscoelastic fluids. Viscoelasticity has a negligible effect on the properties ...
A time-varying subsidence parameterization for the atmospheric boundary layer
Flagg, David D. (David Douglas)
2005-01-01
This study examines the effect of a time-varying parameterization for subsidence in the atmospheric boundary layer (ABL) on a one-dimensional coupled land-atmosphere model. Measurements of large-scale divergence in the ABL ...
LocARNA-P: Accurate boundary prediction and improved detection of structural RNAs
Joshi, T.
Current genomic screens for noncoding RNAs (ncRNAs) predict a large number of genomic regions containing potential structural ncRNAs. The analysis of these data requires highly accurate prediction of ncRNA boundaries and ...
RodrÃguez, Rodolfo
Numerical solution of transient eddy current problems with input current intensities as boundary to solve transient eddy current problems with input current intensities as data, formulated in terms: Eddy current problems, time-dependent electromagnetic problems, input current intensities, finite
Friction and Diapycnal Mixing at a Slope: Boundary Control of Potential Vorticity
Benthuysen, Jessica
Although atmospheric forcing by wind stress or buoyancy flux is known to change the ocean’s potential vorticity (PV) at the surface, less is understood about PV modification in the bottom boundary layer. The adjustment of ...
Dudek, Phebe (Phebe Helena Melania)
2014-01-01
This thesis investigates urban boundaries in the North Zone of Rio de Janeiro. The Zona Norte transitioned in the last hundred years from a rural outskirts area of Rio, into its industrial hinterland, into a fully urbanized ...
Role of {Sigma}5, (210), [001] CSL boundary on displacement cascade in bcc Fe
Nandi, Prithwish K.; Dholakia, Manan; Valsakumar, M. C.
2012-06-05
Molecular dynamics simulations were carried out to understand the role of grain boundaries (GB) on radiation damage in bcc Fe bicrystal. The calculations were performed for a {Sigma}5, (210), [001] symmetric tilt grain boundary for different cases where the primary knock-on atom (PKA) is placed at distances of a{sub csl}, to 15a{sub csl}, from the grain boundary plane. Here, a{sub csl}, is lattice parameter of the coincidence site lattice. Present study shows that the influence of GB on the numbers of surviving defects within a grain is confined within a distance, d{sub opt} < 9a{sub csl}. Our studies also indicate that the grain boundary acts as a reservoir for defects.
Boundary element simulation of oscillating foil with leading-edge separation
Dong, Xiaoxia, S.M. Massachusetts Institute of Technology
2007-01-01
In this thesis, we develop a numerical model to account for the leading-edge separation for the boundary element simulation of the oscillating foil with potential flow assumption. Similar to the trailing-edge separation, ...
Design of a model propulsor for a boundary layer ingesting aircraft
Grasch, Adam D. (Adam Davis)
2013-01-01
This thesis presents contributions to the analysis and design of propulsion simulators for 1:11 and 1:4 scale model wind tunnel investigations of an advanced civil transport aircraft with boundary layer ingestion (BLI). ...
Turbulent combined wave-current boundary layer model for application in coastal waters
Humbyrd, Chelsea Joy
2012-01-01
Accurately predicting transport processes, including sediment transport, in the coastal environment is impossible without correct current velocity and shear stress information. A combined wave-current boundary layer theory ...
Bai, Xiaoli
2011-10-21
The solution of initial value problems (IVPs) provides the evolution of dynamic system state history for given initial conditions. Solving boundary value problems (BVPs) requires finding the system behavior where elements of the states are defined...
Detecting subject boundaries within text: A language-independent statistical approach.
Richmond, Korin; Smith, Andrew James; Amitay, Einat
1997-01-01
We describe here an algorithm for detecting subject boundaries within text based on a statistical lexical similarity measure. Hearst has already tackled this problem with good results (Hearst, 1994). One of her main ...
Variability of the Deep Western Boundary Current at 26.51N during 20042009
, William E. Johns, Silvia L. Garzoli, Erik van Sebille, Darren Rayner, Torsten Kanzow, Molly O. Baringer, 2011; Kanzow et al., 2007; Rayner et al., 2011). The Deep Western Boundary Current (DWBC), first
Modeling stress accelerated grain boundary oxidation (SAGBO) in INCOLOY alloy 908
Soontrapa, Chaiyod
2005-01-01
This study explores the possibility of extending the Ph.D. work of Yan Xu on copper-tin alloys (University of Pennsylvania, 1999) to model stress accelerated grain boundary oxidation (SAGBO) in INCOLOY alloy 908. The steady ...
Detecting dynamical boundaries from kinematic data in biomechanics Shane D. Ross,1
Ross, Shane
Detecting dynamical boundaries from kinematic data in biomechanics Shane D. Ross,1 Martin L. Tanaka analyze problems in musculoskeletal biomechanics, considered as exemplars of a class of experimental, we analyze problems in musculoskeletal biomechanics, considered as exemplars of a class
Efficient numerical methods for capacitance extraction based on boundary element method
Yan, Shu
2006-04-12
algorithms based on boundary element methods (BEM) and to compute the capacitance extraction in the presence of floating dummy conductors. We propose the PHiCap algorithm, which is based on a hierarchical refinement algorithm and the wavelet transform. Unlike...
Preprint of the paper "A General Formulation based on the Boundary Element Method for the Analysis
Colominas, Ignasi
cost) to the analysis of large grounding systems in electrical substations. In this paper we present a new Boundary Element formulation for substation grounding systems embedded in layered soils of the substation site. Obviously, from a technical (and
Kenia, Mayur V. (Mayur Vasant), 1981-
2004-01-01
This thesis focuses on the marriage of magnetic-flux-sensing feedback and boundary-mode operation in a flyback converter to create a simple, small, low-cost, isolated, and tightly regulated power supply. Although each ...
Biogeochemical proxies for environmental and biotic conditions at the Permian-Triassic boundary
Hays, Lindsay Elizabeth
2010-01-01
The extinction at the Permian-Triassic boundary marked one of the most profound events of the Phanerozoic Eon. Although numerous hypotheses have been proposed, the trigger mechanism continues to be debated. This thesis ...
A convective-like energy-stable open boundary condition for ...
S. Dong
2015-09-21
Sep 15, 2015 ... boundary condition ensures the energy stability of the system, even when strong vortices or backflows occur .... The objective of the current paper is twofold. First, we present ...... three-dimensional flow transition occurs. The lift ...
Stress in the lithosphere from non-tectonic loads with implications for plate boundary processes
Luttrell, Karen M
2010-01-01
Ocean loading effects on stress at near shore plate boundaryFault interaction by elastic stress changes: New clues fromand J. Lin (1994), Static Stress Changes and the Triggering
integrated Wireless Information Network (iWIN) Lab A Robust Boundary Detection
Wu, Hongyi
· Related work · Motivation · Coconut algorithm · Simulation · Conclusion #12;integrated Wireless;integrated Wireless Information Network (iWIN) Lab OUTLINE · Introduction · Coconut algorithm · Coarse · Conclusion #12;integrated Wireless Information Network (iWIN) Lab COCONUT ALGORITHM · Coarse Boundary Surface
Wanakamol, Panitarn
2006-01-01
Model bicrystals made by adhering pieces of near-single-crystal styrene-isoprene-styrene (SIS) cylindrical block copolymer (BCP), produced by a roll-casting process; yield various types of pure tilt grain boundaries. The ...
The hydrodynamic stability of crossflow vortices in the Bdewadt boundary layer
The hydrodynamic stability of crossflow vortices in the Bödewadt boundary layer N. A. Culverhouse the critical Reynolds number. extends the laminar flow region. decreasing the magnitude of the crossflow
Seismic and gravitational studies of melting in the mantle's thermal boundary layers
Van Ark, Emily M
2007-01-01
This thesis presents three studies which apply geophysical tools to the task of better understanding mantle melting phenomena at the upper and lower boundaries of the mantle. The first study uses seafloor bathymetry and ...
Intersection theory on the moduli space of holomorphic curves with Lagrangian boundary conditions
Solomon, Jake P. (Jake Philip)
2006-01-01
We define a new family of open Gromov-Witten type invariants based on intersection theory on the moduli space of pseudoholomorphic curves of arbitrary genus with boundary in a Lagrangian submanifold. We assume the Lagrangian ...
Broader source: Energy.gov [DOE]
This study was conducted to understand how to increase engine efficiency by reducing parasitic boundary regime friction losses and enable operation with lower viscosity oils while maintaining engine durability.
Zhang, Yang, Ph. D. Massachusetts Institute of Technology
2009-01-01
In this thesis, the influence of boundary layer processes and seasonal forcing on baroclinic eddy equilibration is studied to understand how the baroclinic adjustment is modified when taking into account these two factors. ...
Taylor, John R.
UNIVERSITY OF CALIFORNIA, SAN DIEGO Numerical Simulations of the Stratified Oceanic Bottom Boundary of Philosophy in Mechanical Engineering by John R. Taylor Committee in charge: Sutanu Sarkar, Chair Thomas Simulation of Stably Stratified Open Channel Flow . . . . . 6 1. Introduction
Reisenfeld, D. B.
The ecliptic poles are observed continuously by the Interstellar Boundary Explorer (IBEX); thus, it is possible to discern temporal variations in the energetic neutral atoms (ENAs) from the outer heliosphere on timescales ...
Luo Yousong, E-mail: yluo@rmit.edu.a [RMIT University, School of Mathematical and Geospatial Sciences (Australia)
2010-06-15
In this paper we derive a necessary optimality condition for a local optimal solution of some control problems. These optimal control problems are governed by a semi-linear Vettsel boundary value problem of a linear elliptic equation. The control is applied to the state equation via the boundary and a functional of the control together with the solution of the state equation under such a control will be minimized. A constraint on the solution of the state equation is also considered.
Burk, D.E.; Kanner, S.; Muyshondt, J.E.; Shaulis, D.S.; Russell, P.E.
1983-01-01
In order to determine the surface recombination velocity at a grain boundary surface, computer-aided calculations of the theoretical electron-beam-induced-current response to a point source excitation are fitted to data taken as a function of distance from the grain boundary. It is demonstrated that the data is in good agreement with this theoretical response for distances greater than two maximum penetration depths of the incident electron beam.
Multiscale simulation of xenon diffusion and grain boundary segregation in UO?
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Andersson, David A.; Tonks, Michael R.; Casillas, Luis; Vyas, Shyam; Nerikar, Pankaj; Uberuaga, Blas P.; Stanek, Christopher R.
2015-07-01
In light water reactor fuel, gaseous fission products segregate to grain boundaries, resulting in the nucleation and growth of large intergranular fission gas bubbles. The segregation rate is controlled by diffusion of fission gas atoms through the grains and interaction with the boundaries. Based on the mechanisms established from earlier density functional theory (DFT) and empirical potential calculations, diffusion models for xenon (Xe), uranium (U) vacancies and U interstitials in UO? have been derived for both intrinsic (no irradiation) and irradiation conditions. Segregation of Xe to grain boundaries is described by combining the bulk diffusion model with a model formore »the interaction between Xe atoms and three different grain boundaries in UO? (?5 tilt, ?5 twist and a high angle random boundary), as derived from atomistic calculations. The present model does not attempt to capture nucleation or growth of fission gas bubbles at the grain boundaries. The point defect and Xe diffusion and segregation models are implemented in the MARMOT phase field code, which is used to calculate effective Xe and U diffusivities as well as to simulate Xe redistribution for a few simple microstructures.« less
Li, An-Ping [ORNL; Clark, Kendal W [ORNL; Zhang, Xiaoguang [ORNL; Vlassiouk, Ivan V [ORNL; He, Guowei [Carnegie Mellon University (CMU); Feenstra, Randall [Carnegie Mellon University (CMU)
2013-01-01
Graphene films can now be produced on the scale of up to meters. However, all large-scale graphene films contain topological defects that can significantly affect the characteristic transport behaviors of graphene. Here, we spatially map the structures and electronic transport near specific domain and grain boundaries in graphene, and evaluate effects of different types of defect on the electronic conductivity in epitaxial graphene grown on SiC and CVD graphene on Cu subsequently transferred to a SiO2 substrate. We use a combined approach with a multi-probe scanning tunneling potentiometry to investigate both structures and transport at individual grain boundaries and domain boundaries that are defined by coalesced grains, surface steps, and changes in layer thickness. It is found that the substrate step on SiC presents a significant potential barrier for electron transport of epitaxial graphene due to the reduced charge transport from the substrate at the step edges, monolayer-bilayer boundaries exhibit a high resistivity that can change depending on directions of the current across the boundary, and the resistivity of grain boundaries changes with the transition width of the disordered region between two adjacent grains in graphene. The detailed understanding of graphene defects will provide the feedback for controlled engineering of defects in large-scale graphene films.
A. Abdesselam; I. Adachi; K. Adamczyk; H. Aihara; S. Al Said; K. Arinstein; Y. Arita; D. M. Asner; T. Aso; V. Aulchenko; T. Aushev; R. Ayad; T. Aziz; V. Babu; I. Badhrees; S. Bahinipati; A. M. Bakich; A. Bala; Y. Ban; V. Bansal; E. Barberio; M. Barrett; W. Bartel; A. Bay; I. Bedny; P. Behera; M. Belhorn; K. Belous; V. Bhardwaj; B. Bhuyan; M. Bischofberger; S. Blyth; A. Bobrov; A. Bondar; G. Bonvicini; C. Bookwalter; A. Bozek; M. Bra\\v{c; ko; J. Brodzicka; T. E. Browder; D. \\v{Cervenkov; M. -C. Chang; P. Chang; Y. Chao; V. Chekelian; A. Chen; K. -F. Chen; P. Chen; B. G. Cheon; K. Chilikin; R. Chistov; K. Cho; V. Chobanova; S. -K. Choi; Y. Choi; D. Cinabro; J. Crnkovic; J. Dalseno; M. Danilov; S. Di Carlo; J. Dingfelder; Z. Dole\\v{z; al; Z. Drásal; A. Drutskoy; S. Dubey; D. Dutta; K. Dutta; S. Eidelman; D. Epifanov; S. Esen; H. Farhat; J. E. Fast; M. Feindt; T. Ferber; A. Frey; O. Frost; M. Fujikawa; B. G. Fulsom; V. Gaur; N. Gabyshev; S. Ganguly; A. Garmash; D. Getzkow; R. Gillard; F. Giordano; R. Glattauer; Y. M. Goh; B. Golob; M. Grosse Perdekamp; J. Grygier; O. Grzymkowska; H. Guo; J. Haba; P. Hamer; Y. L. Han; K. Hara; T. Hara; Y. Hasegawa; J. Hasenbusch; K. Hayasaka; H. Hayashii; X. H. He; M. Heck; M. Hedges; D. Heffernan; M. Heider; A. Heller; T. Higuchi; S. Himori; T. Horiguchi; Y. Horii; Y. Hoshi; K. Hoshina; W. -S. Hou; Y. B. Hsiung; M. Huschle; H. J. Hyun; Y. Igarashi; T. Iijima; M. Imamura; K. Inami; A. Ishikawa; K. Itagaki; R. Itoh; M. Iwabuchi; M. Iwasaki; Y. Iwasaki; T. Iwashita; S. Iwata; I. Jaegle; M. Jones; K. K. Joo; T. Julius; D. H. Kah; H. Kakuno; J. H. Kang; K. H. Kang; P. Kapusta; S. U. Kataoka; N. Katayama; E. Kato; Y. Kato; P. Katrenko; H. Kawai; T. Kawasaki; H. Kichimi; C. Kiesling; B. H. Kim; D. Y. Kim; H. J. Kim; J. B. Kim; J. H. Kim; K. T. Kim; M. J. Kim; S. H. Kim; S. K. Kim; Y. J. Kim; K. Kinoshita; C. Kleinwort; J. Klucar; B. R. Ko; N. Kobayashi; S. Koblitz; P. Kody\\v{s; Y. Koga; S. Korpar; R. T. Kouzes; P. Kri\\v{z; an; P. Krokovny; B. Kronenbitter; T. Kuhr; R. Kumar; T. Kumita; E. Kurihara; Y. Kuroki; A. Kuzmin; P. Kvasni\\v{ck}a; Y. -J. Kwon; Y. -T. Lai; J. S. Lange; D. H. Lee; I. S. Lee; S. -H. Lee; M. Leitgab; R. Leitner; P. Lewis; J. Li; X. Li; Y. Li; L. Li Gioi; J. Libby; A. Limosani; C. Liu; Y. Liu; Z. Q. Liu; D. Liventsev; R. Louvot; P. Lukin; J. MacNaughton; D. Matvienko; A. Matyja; S. McOnie; Y. Mikami; K. Miyabayashi; Y. Miyachi; H. Miyake; H. Miyata; Y. Miyazaki; R. Mizuk; G. B. Mohanty; S. Mohanty; D. Mohapatra; A. Moll; H. K. Moon; T. Mori; H. -G. Moser; T. Müller; N. Muramatsu; R. Mussa; T. Nagamine; Y. Nagasaka; Y. Nakahama; I. Nakamura; K. Nakamura; E. Nakano; H. Nakano; T. Nakano; M. Nakao; H. Nakayama; H. Nakazawa; T. Nanut; Z. Natkaniec; M. Nayak; E. Nedelkovska; K. Negishi; K. Neichi; C. Ng; C. Niebuhr; M. Niiyama; N. K. Nisar; S. Nishida; K. Nishimura; O. Nitoh; T. Nozaki; A. Ogawa; S. Ogawa; T. Ohshima; S. Okuno; S. L. Olsen; Y. Ono; Y. Onuki; W. Ostrowicz; C. Oswald; H. Ozaki; P. Pakhlov; G. Pakhlova; H. Palka; E. Panzenböck; C. -S. Park; C. W. Park; H. Park; H. K. Park; K. S. Park; L. S. Peak; T. K. Pedlar; T. Peng; L. Pesantez; R. Pestotnik; M. Peters; M. Petri?; L. E. Piilonen; A. Poluektov; K. Prasanth; M. Prim; K. Prothmann; C. Pulvermacher; B. Reisert; E. Ribe\\v{z; l; M. Ritter; M. Röhrken; J. Rorie; A. Rostomyan; M. Rozanska; S. Ryu; H. Sahoo; T. Saito; K. Sakai; Y. Sakai; S. Sandilya; D. Santel; L. Santelj; T. Sanuki; N. Sasao; Y. Sato; V. Savinov; O. Schneider; G. Schnell; P. Schönmeier; M. Schram; C. Schwanda; A. J. Schwartz; B. Schwenker; R. Seidl; A. Sekiya; D. Semmler; K. Senyo; O. Seon; I. Seong; M. E. Sevior; L. Shang; M. Shapkin; V. Shebalin; C. P. Shen; T. -A. Shibata; H. Shibuya; S. Shinomiya; J. -G. Shiu; B. Shwartz; A. Sibidanov; F. Simon; J. B. Singh; R. Sinha; P. Smerkol; Y. -S. Sohn; A. Sokolov; Y. Soloviev; E. Solovieva; S. Stani?; M. Stari?; M. Steder; J. Stypula; S. Sugihara; A. Sugiyama; M. Sumihama; K. Sumisawa; T. Sumiyoshi; K. Suzuki; S. Suzuki; S. Y. Suzuki; Z. Suzuki; H. Takeichi; U. Tamponi; M. Tanaka; S. Tanaka; K. Tanida; N. Taniguchi; G. Tatishvili; G. N. Taylor; Y. Teramoto; F. Thorne; I. Tikhomirov; K. Trabelsi; V. Trusov; Y. F. Tse; T. Tsuboyama; M. Uchida; T. Uchida; Y. Uchida; S. Uehara; K. Ueno; T. Uglov; Y. Unno; S. Uno; P. Urquijo; Y. Ushiroda; Y. Usov; S. E. Vahsen; C. Van Hulse; P. Vanhoefer; G. Varner; K. E. Varvell; K. Vervink; A. Vinokurova; V. Vorobyev; A. Vossen; M. N. Wagner; C. H. Wang; J. Wang; M. -Z. Wang; P. Wang; X. L. Wang; M. Watanabe; Y. Watanabe; R. Wedd; S. Wehle; E. White; J. Wiechczynski; K. M. Williams; E. Won; B. D. Yabsley; S. Yamada; H. Yamamoto; J. Yamaoka; Y. Yamashita; M. Yamauchi; S. Yashchenko; J. Yelton; Y. Yook; C. Z. Yuan; Y. Yusa; C. C. Zhang; L. M. Zhang; Z. P. Zhang; L. Zhao; V. Zhilich; V. Zhulanov; M. Ziegler; T. Zivko; A. Zupanc; N. Zwahlen; O. Zyukova; The Belle Collaboration
2015-03-04
We report a measurement of the amplitude ratio $r_S$ of $B^0 \\to D^0K^{*0}$ and $B^0 \\to \\bar{D^0}K^{*0}$ decays with a model-independent Dalitz plot analysis using $D\\to K_S^0\\pi^+\\pi^-$ decays. Using the full data sample of $772\\times10^6$ $B\\bar{B}$ pairs collected at the $\\Upsilon(4S)$ resonance with the Belle detector at KEKB accelerator the upper limit is $r_S < 0.87$ at the 68 % confidence level. This result is the first measurement of $r_S$ with a model-independent Dalitz analysis, and is consistent with results from other analyses. The value of $r_S$ indicates the sensitivity of the decay to $\\phi_3$ because the statistical uncertainty is proportional to $1/r_S$. The $r_S$ result is obtained from observables ($x_\\pm$, $y_\\pm$) \\begin{eqnarray} x_- &=& +0.4 ^{+1.0 +0.0}_{-0.6 -0.1} \\pm0.0 \\\\ y_- &=& -0.6 ^{+0.8 +0.1}_{-1.0 -0.0} \\pm0.1 \\\\ x_+ &=& +0.1 ^{+0.7 +0.0}_{-0.4 -0.1} \\pm0.1 \\\\ y_+ &=& +0.3 ^{+0.5 +0.0}_{-0.8 -0.1} \\pm0.1 \\\\ , \\end{eqnarray} where $x_\\pm = r_S \\cos(\\delta_S \\pm \\phi_3)$, $y_\\pm = r_S \\sin(\\delta_S \\pm \\phi_3)$ and $\\phi_3 (\\delta_S)$ are the weak (strong) phase difference between $B^0 \\to D^0K^{*0}$ and $B^0 \\to \\bar{D^0}K^{*0}$. The first uncertainty is statistical, the second is the experimental systematic and the third is the systematic due to the uncertainties on $c_i$ and $s_i$ parameters measured by CLEO.
General Considerations of the Electrostatic Boundary Conditions in Oxide Heterostructures
Higuchi, Takuya
2011-08-19
When the size of materials is comparable to the characteristic length scale of their physical properties, novel functionalities can emerge. For semiconductors, this is exemplified by the 'superlattice' concept of Esaki and Tsu, where the width of the repeated stacking of different semiconductors is comparable to the 'size' of the electrons, resulting in novel confined states now routinely used in opto-electronics. For metals, a good example is magnetic/non-magnetic multilayer films that are thinner than the spin-scattering length, from which giant magnetoresistance (GMR) emerged, used in the read heads of hard disk drives. For transition metal oxides, a similar research program is currently underway, broadly motivated by the vast array of physical properties that they host. This long-standing notion has been recently invigorated by the development of atomic-scale growth and probe techniques, which enables the study of complex oxide heterostructures approaching the precision idealized in Fig. 1(a). Taking the subset of oxides derived from the perovskite crystal structure, the close lattice match across many transition metal oxides presents the opportunity, in principle, to develop a 'universal' heteroepitaxial materials system. Hand-in-hand with the continual improvements in materials control, an increasingly relevant challenge is to understand the consequences of the electrostatic boundary conditions which arise in these structures. The essence of this issue can be seen in Fig. 1(b), where the charge sequence of the sublayer 'stacks' for various representative perovskites is shown in the ionic limit, in the (001) direction. To truly 'universally' incorporate different properties using different materials components, be it magnetism, ferroelectricity, superconductivity, etc., it is necessary to access and join different charge sequences, labelled here in analogy to the designations 'group IV, III-V, II-VI' for semiconductors. As we will review, interfaces between different families creates a host of electrostatic issues. They can be somewhat avoided if, as in many semiconductor heterostructures, only one family is used, with small perturbations (such as n-type or p-type doping) around them. However, for most transition metal oxides, this is greatly restrictive. For example, LaMnO{sub 3} and SrMnO{sub 3} are both insulators in part due to strong electron correlations, and only in their solid solution does 'colossal magnetoresistance' emerge in bulk. Similarly, the metallic superlattice shown in Fig. 1(c) can be considered a nanoscale deconstruction of (La,Sr)TiO{sub 3} to the insulating parent compounds. Therefore the aspiration to arbitrarily mix and match perovskite components requires a basic understanding of, and ultimately control over, these issues. In this context, here we present basic electrostatic features that arise in oxide heterostructures which vary the ionic charge stacking sequence. In close relation to the analysis of the stability of polar surfaces and semiconductor heterointerfaces, the variation of the dipole moment across a heterointerface plays a key role in determining its stability. Different self-consistent assignments of the unit cell are presented, allowing the polar discontinuity picture to be recast in terms of an equivalent local charge neutrality picture. The latter is helpful in providing a common framework with which to discuss electronic reconstructions, local-bonding considerations, crystalline defects, and lattice polarization on an equal footing, all of which are the subject of extensive current investigation.
Uranium vacancy mobility at the sigma 5 symmetric tilt grain boundary in UO2
Uberuaga, Blas P.
2012-05-02
An important consequence of the fissioning process occurring during burnup is the formation of fission products. These fission products alter the thermo-mechanical properties of the fuel. They also lead to macroscopic changes in the fuel structure, including the formation of bubbles that are connected to swelling of the fuel. Subsequent release of fission gases increase the pressure in the plenum and can cause changes in the properties of the fuel pin itself. It is thus imperative to understand how fission products, and fission gases in particular, behave within the fuel in order to predict the performance of the fuel under operating conditions. Fission gas redistribution within the fuel is governed by mass transport and the presence of sinks such as impurities, dislocations, and grain boundaries. Thus, to understand how the distribution of fission gases evolves in the fuel, we must understand the underlying transport mechanisms, tied to the concentrations and mobilities of defects within the material, and how these gases interact with microstructural features that might act as sinks. Both of these issues have been addressed in previous work under NEAMS. However, once a fission product has reached a sink, such as a grain boundary, its mobility may be different there than in the grain interior and predicting how, for example, bubbles nucleate within grain boundaries necessitates an understanding of how fission gases diffuse within boundaries. That is the goal of the present work. In this report, we describe atomic level simulations of uranium vacancy diffusion in the pressence of a {Sigma}5 symmetric tilt boundary in urania (UO{sub 2}). This boundary was chosen as it is the simplest of the boundaries we considered in previous work on segregation and serves as a starting point for understanding defect mobility at boundaries. We use a combination of molecular statics calculations and kinetic Monte Carlo (kMC) to determine how the mobility of uranium vacancies is altered at this particular grain boundary. Given that the diffusion of fission gases such as Xe are tied to the mobility of uranium vacancies, these results given insight into how fission gas mobility differs at grain boundaries compared to bulk urania.
Angel Unaware and Other K/S Stories
M.R.L.
1986-01-01
Highly accurate density data is required for engineering calculations to make property estimations in natural gas custody transfer through pipelines. It is also essential to have accurate pressure-volume-temperature (PVT) ...
SURESH K.S. VANNAN Oak Ridge National Laboratory (ORNL)
Post, Wilfred M.
- Present Oak Ridge, TN, USA Job Functions · Manage tasks, staffing, finance, and reporting for NASA funded scientific activities (e.g. deforestation studies in Africa, environmental impact of oil exploration in Gabon
INTERNAL CURING RESEARCH ON US-54 IN ALLEN CO, KS
Cast 9:30 AM 10:30 AM Initial Set 6:10 PM (8:40 hours) 4:30 PM (6:00 hours) Final Set 10:20 PM (12 28 Day Shrinkage 0.030% 0.035% 28 Day Elastic Modulus 3500 ksi 3630 ksi 28 Day Poisson's Ratio 0.21 0
Many-body microhydrodynamics of colloidal particles with active boundary layers
Rajesh Singh; Somdeb Ghose; R. Adhikari
2015-07-13
Colloidal particles with active boundary layers - regions surrounding the particles where nonequilibrium processes produce large velocity gradients - are common in many physical, chemical and biological contexts. The velocity or stress at the edge of the boundary layer determines the exterior fluid flow and, hence, the many-body interparticle hydrodynamic interaction. Here, we present a method to compute the many-body hydrodynamic interaction between $N$ spherical active particles induced by their exterior microhydrodynamic flow. First, we use a boundary integral representation of the Stokes equation to eliminate bulk fluid degrees of freedom. Then, we expand the boundary velocities and tractions of the integral representation in an infinite-dimensional basis of tensorial spherical harmonics and, on enforcing boundary conditions in a weak sense on the surface of each particle, obtain a system of linear algebraic equations for the unknown expansion coefficients. The truncation of the infinite series, fixed by the degree of accuracy required, yields a finite linear system that can be solved accurately and efficiently by iterative methods. The solution linearly relates the unknown rigid body motion to the known values of the expansion coefficients, motivating the introduction of propulsion matrices. These matrices completely characterize hydrodynamic interactions in active suspensions just as mobility matrices completely characterize hydrodynamic interactions in passive suspensions. The reduction in the dimensionality of the problem, from a three-dimensional partial differential equation to a two-dimensional integral equation, allows for dynamic simulations of hundreds of thousands of active particles on multi-core computational architectures.
Combustion-turbulence interaction in the turbulent boundary layer over a hot surface
Ng, T.T.; Cheng, R.K.; Robben, F.; Talbot, L.
1982-01-01
The turbulence-combustion interaction in a reacting turbulent boundary layer over a heated flat plate was studied. Ethylene/air mixture with equivalence ratio of 0.35 was used. The free stream velocity was 10.5 m/s and the wall temperature was 1250/sup 0/K. Combustion structures visualization was provided by high-speed schlieren photographs. Fluid density statistics were deduced from Rayleigh scattering intensity measurements. A single-component laser Doppler velocimetry system was used to obtain mean and root-mean-square velocity distributions, the Reynolds stress, the streamwise and the cross-stream turbulent kinetic energy diffusion, and the production of turbulent kinetic energy by Reynolds stress. The combustion process was dominated by large-scale turbulent structures of the boundary layer. Combustion causes expansion of the boundary layer. No overall self-similarity is observed in either the velocity or the density profiles. Velocity fluctuations were increased in part of the boundary layer and the Reynolds stress was reduced. The turbulent kinetic energy diffusion pattern was changed significantly and a modification of the boundary layer assumption will be needed when dealing with this problem analytically. 11 figures, 1 table.
Effect of Grain Boundaries on Krypton Segregation Behavior in Irradiated Uranium Dioxide
Valderrama, Billy [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; He, Lingfeng [Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics; Henderson, Hunter B. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Pakarinen, Janne [Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics; Jaques, Brian [Boise State Univ., Boise, Idaho (United States). Dept. of Materials Science and Engineering; Gan, Jian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Butt, Darryl P. [Boise State Univ., Boise, Idaho (United States). Dept. of Materials Science and Engineering; Allen, Todd R. [Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics; Idaho National Lab. (INL), Idaho Falls, ID (United States); Manuel, Michele V. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering
2014-12-01
Fission products, such as krypton (Kr), are known to be insoluble within UO_{2}, segregating towards grain boundaries, eventually leading to a lowering of the thermal conductivity and fuel swelling. Recent computational studies have identified that differences in grain boundary structure have a significant effect on the segregation behavior of fission products. However, experimental work supporting these simulations is lacking. Atom probe tomography was used to measure the Kr distribution across grain boundaries in UO_{2}. Polycrystalline depleted-UO_{2} samples was irradiated with 0.7 and 1.8 MeV Kr-ions and annealed to 1000ºC, 1300ºC, and 1600°C for 1 hour to produce a Kr-bubble dominated microstructure. The results of this work indicate a strong dependence of Kr concentration as a function of grain boundary structure. Temperature also influences grain boundary chemistry with greater Kr concentration evident at higher temperatures, resulting in a reduced Kr concentration in the bulk. While Kr migration is active at elevated temperatures, no changes in grain size or texture were observed in the irradiated UO_{2} samples.
On the Beavers-Joseph-Saffman boundary condition for curved interfaces
Sören Dobberschütz
2015-04-22
The appropriate boundary condition between an unconfined incompressible viscous fluid and a porous medium is given by the law of Beavers and Joseph. The latter has been justified both experimentally and mathematically, using the method of periodic homogenisation. However, all results so far deal only with the case of a planar boundary. In this work, we consider the case of a curved, macroscopically periodic boundary. By using a coordinate transformation, we obtain a description of the flow in a domain with a planar boundary, for which we derive the effective behaviour: The effective velocity is continuous in normal direction. Tangential to the interface, a slip occurs. Additionally, a pressure jump occurs. The magnitude of the slip velocity as well as the jump in pressure can be determined with the help of a generalised boundary layer function. The results indicate the validity of a generalised law of Beavers and Joseph, where the geometry of the interface has an influence on the slip and jump constants.
DNS of laminar-turbulent boundary layer transition induced by solid obstacles
Orlandi, Paolo; Bernardini, Matteo
2015-01-01
Results of numerical simulations obtained by a staggered finite difference scheme together with an efficient immersed boundary method are presented to understand the effects of the shape of three-dimensional obstacles on the transition of a boundary layer from a laminar to a turbulent regime. Fully resolved Direct Numerical Simulations (DNS), highlight that the closer to the obstacle the symmetry is disrupted the smaller is the transitional Reynolds number. It has been also found that the transition can not be related to the critical roughness Reynolds number used in the past. The simulations highlight the differences between wake and inflectional instabilities, proving that two-dimensional tripping devices are more efficient in promoting the transition. Simulations at high Reynolds number demonstrate that the reproduction of a real experiment with a solid obstacle at the inlet is an efficient tool to generate numerical data bases for understanding the physics of boundary layers. The quality of the numerical ...
SPHERICALLY SYMMETRIC RANDOM WALKS III. POLYMER ADSORPTION AT A HYPERSPHERICAL BOUNDARY
Carl M. Bender; Peter N. Meisinger; Stefan Boettcher
1995-06-06
A recently developed model of random walks on a $D$-dimensional hyperspherical lattice, where $D$ is {\\sl not} restricted to integer values, is used to study polymer growth near a $D$-dimensional attractive hyperspherical boundary. The model determines the fraction $P(\\kappa)$ of the polymer adsorbed on this boundary as a function of the attractive potential $\\kappa$ for all values of $D$. The adsorption fraction $P(\\kappa)$ exhibits a second-order phase transition with a nontrivial scaling coefficient for $04$. At $D=4$ there is a tricritical point with logarithmic scaling. This model reproduces earlier results for $D=1$ and $D=2$, where $P(\\kappa)$ scales linearly and exponentially, respectively. A crossover transition that depends on the radius of the adsorbing boundary is found.
Bayerschen, E; Wulfinghoff, S; Weygand, D; Böhlke, T
2015-01-01
The gradient crystal plasticity framework of Wulfinghoff et al. [53] incorporating an equivalent plastic strain and grain boundary yielding, is extended with additional grain boundary hardening. By comparison to averaged results from many discrete dislocation dynamics (DDD) simulations of an aluminum type tricrystal under tensile loading, the new hardening parameter in the continuum model is calibrated. It is shown that although the grain boundaries (GBs) in the discrete simulations are impenetrable, an infinite GB yield strength corresponding to microhard GB conditions, is not applicable in the continuum model. A combination of a finite GB yield strength with an isotropic bulk Voce hardening relation alone also fails to model the plastic strain profiles obtained by DDD. Instead, a finite GB yield strength in combination with GB hardening depending on the equivalent plastic strain at the GBs is shown to give a better agreement to DDD results. The differences in the plastic strain profiles obtained in DDD simu...
Boundary Behavior of the Ginzburg-Landau Order Parameter in the Surface Superconductivity Regime
M. Correggi; N. Rougerie
2015-01-27
We study the 2D Ginzburg-Landau theory for a type-II superconductor in an applied magnetic field varying between the second and third critical value. In this regime the order parameter minimizing the GL energy is concentrated along the boundary of the sample and is well approximated to leading order by a simplified 1D profile in the direction perpendicular to the boundary. Motivated by a conjecture of Xing-Bin Pan, we address the question of whether this approximation can hold uniformly in the boundary region. We prove that this is indeed the case as a corollary of a refined, second order energy expansion including contributions due to the curvature of the sample. Local variations of the GL order parameter are controlled by the second order term of this energy expansion, which allows us to prove the desired uniformity of the surface superconductivity layer.
Negative plasma potential in a multidipole chamber with a dielectric coated plasma boundary
Sheehan, J. P.; Hershkowitz, Noah
2012-05-15
Negative plasma potentials with respect to a grounded wall that was coated with a dielectric have been achieved in an electropositive plasma confined by a multidipole device. A Langmuir probe was used to measure the density and temperatures of the bi-Maxwellian distribution electrons and an emissive probe was used to measure the plasma potential profile near the plasma boundary. For many discharge parameters, the potential profile was that of a typical electropositive sheath, but it was shifted negative due to negative charge accumulated on the plasma-surface boundary. A virtual cathode was observed near the boundary when the neutral pressure, primary electron energy, and/or discharge current were low ({approx}2 x 10{sup -4} Torr, {approx}60 eV, and 80 mA, respectively). The behavior of the sheath potential was shown to be consistent with that predicted by particle balance and a qualitative mechanism for wall charging is presented.
Zhang, Hao; Trias, F Xavier; Yu, Aibing; Tan, Yuanqiang; Oliva, Assensi
2015-01-01
In our recent work [H. Zhang, F.X. Trias, A. Oliva, D. Yang, Y. Tan, Y. Sheng. PIBM: Particulate immersed boundary method for fluid-particle interaction problems. Powder Technology. 272(2015), 1-13.], a particulate immersed boundary method (PIBM) for simulating fluid-particle multiphase flow was proposed and assessed in both two- and three-dimensional applications. In this study, the PIBM was extended to solve thermal interaction problems between spherical particles and fluid. The Lattice Boltzmann Method (LBM) was adopted to solve the fluid flow and temperature fields, the PIBM was responsible for the non-slip velocity and temperature boundary conditions at the particle surface, and the kinematics and trajectory of the solid particles were evaluated by the Discrete Element Method (DEM). Four case studies were implemented to demonstrate the capability of the current coupling scheme. Firstly, numerical simulation of natural convection in a two-dimensional square cavity with an isothermal concentric annulus was...
Short time heat diffusion in compact domains with discontinuous transmission boundary conditions
Claude Bardos; Denis Grebenkov; Anna Rozanova-Pierrat
2015-09-07
We consider a heat problem with discontinuous diffusion coefficientsand discontinuous transmission boundary conditions with a resistancecoefficient. For all compact $(\\epsilon,\\delta)$-domains $\\Omega\\subset\\mathbb{R}^n$ with a $d$-set boundary (for instance, aself-similar fractal), we find the first term of the small-timeasymptotic expansion of the heat content in the complement of$\\Omega$, and also the second-order term in the case of a regularboundary. The asymptotic expansion is different for the cases offinite and infinite resistance of the boundary. The derived formulasrelate the heat content to the volume of the interior Minkowskisausage and present a mathematical justification to the de Gennes'approach. The accuracy of the analytical results is illustrated bysolving the heat problem on prefractal domains by a finite elementsmethod.
A Gaussian-Like Immersed Boundary Kernel with Improved Translational Invariance and Smoothness
Bao, Yuan-Xun; Peskin, Charles S
2015-01-01
The immersed boundary (IB) method is a general mathematical framework for studying problems involving fluid-structure interactions in which an elastic structure is immersed in a viscous incompressible fluid. In the IB formulation, the fluid described by Eulerian variables is coupled with the immersed structure described by Lagrangian variables via the use of the Dirac delta function. From a numerical standpoint, the Lagrangian force spreading and the Eulerian velocity interpolation are carried out by a regularized, compactly supported discrete delta function or kernel. Immersed-boundary kernels are derived from a certain set of postulates to achieve approximate grid translational invariance, interpolation accuracy and computational efficiency. In this note, we present a new 6-point immersed-boundary kernel that is $\\mathcal{C}^3$ and features a substantially improved translational invariance compared to other common IB kernels.
Heat Transfer Boundary Conditions in the RELAP5-3D Code
Richard A. Riemke; Cliff B. Davis; Richard R. Schultz
2008-05-01
The heat transfer boundary conditions used in the RELAP5-3D computer program have evolved over the years. Currently, RELAP5-3D has the following options for the heat transfer boundary conditions: (a) heat transfer correlation package option, (b) non-convective option (from radiation/conduction enclosure model or symmetry/insulated conditions), and (c) other options (setting the surface temperature to a volume fraction averaged fluid temperature of the boundary volume, obtaining the surface temperature from a control variable, obtaining the surface temperature from a time-dependent general table, obtaining the heat flux from a time-dependent general table, or obtaining heat transfer coefficients from either a time- or temperature-dependent general table). These options will be discussed, including the more recent ones.
Phase transitions in a reaction-diffusion model on a line with boundaries
Khorrami, Mohammad Aghamohammadi, Amir
2014-03-15
A one-dimensional model on a line of length L is investigated, which involves particle diffusion as well as single particle annihilation. There are also creation and annihilation at the boundaries. The static and dynamical behaviors of the system are studied. It is seen that the system could exhibit a dynamical phase transition. For small drift velocities, the relaxation time does not depend on the absorption rates at the boundaries. This is the fast phase. For large velocities, the smaller of the absorption rates at boundaries enter the relaxation rate and makes it longer. This is the slow phase. Finally, the effect of a random particle creation in the bulk is also investigated.
Grindinger, C.M.
1992-05-01
This study uses Hawaiian Rainband Project (HaRP) data, from the summer of 1991, to show a boundary layer wind profiler can be used to measure the trade wind inversion. An algorithm has been developed for the profiler that objectively measures the depth of the moist oceanic boundary layer. The Hilo inversion, measured by radiosonde, is highly correlated with the moist oceanic boundary layer measured by the profiler at Paradise Park. The inversion height on windward Hawaii is typically 2253 + or - 514 m. The inversion height varies not only on a daily basis, but on less than an hourly basis. It has a diurnal, as well as a three to four day cycle. There appears to be no consistent relationship between inversion height and precipitation. Currently, this profiler is capable of making high frequency (12 minute) measurements of the inversion base variation, as well as other features.
Simulations of dislocation pile-ups at assymetric tilt boundaries in aluminum
Valone, Steven [Los Alamos National Laboratory; Wang, Jian M [Los Alamos National Laboratory; Hoagland, Richard C [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory
2011-01-21
Materials deformation processes are increasingly approachable through the both conventional and accelerated molecular dynamics. In one deformation process, dislocation pile-up at a grain boundary, a greater understanding is required as to how dislocations transmit through grain boundaries, causing plastic deformation, or reflect and reconstruct the grain boundary, but with no macroscopic deformation. Here dislocation pile-ups in an alwninum bicrystal with an asymmetric tilt grain boundary are simulated atomistically, introducing effects of dislocation interactions beyond linear elastic ones. The observed responses as functions of the number of explicitly modeled dislocations and the magnitude of the applied stress are discussed. Typical conditions for the simulations consist of thermal relaxation room temperature, five active dislocations inserted within a 6.5-million-atom cell, and an additional fourteen dislocations represented within the atomistic simulation by their elastic strain fields. The dislocations are initially distributed according to linear elastic estimates of their positions in a double-ended pile-up from a chosen far-field stress. The whole cell is allowed to relax according to a procedure to be described. In the ensuing simulations, the system is propagated for some substantial period of time (lOs of ps), followed by small increments of strain. After a number of such increments, we observe all of the anticipated events. Usually several of the closest dislocations are absorbed into the grain boundary, resulting in varying amounts of reconstruction. Reflections from the boundary are common and show a strong dependence on sample thickness. Transmission events are seen on both slip systems in the other grain. The particulars of these events will be described as well.
Computer Modeling of Transport of Oxidizing Species in Grain Boundaries during Zirconium Corrosion
Xian-Ming Bai; Yongfeng Zhang; Michael R. Tonks
2014-06-01
Zirconium (Zr) based alloys are widely used as the cladding materials in light-water reactors. The water-side corrosion of these alloys degrades their structural integrity and poses serious safety concerns. During the Zr corrosion process, a thin Zr oxide (ZrO2) layer forms on the alloy surface and serves as a barrier layer for further corrosion. The majority of the oxide has the monoclinic phase. At the transition region between the oxide and the metal, the oxide contains a thin layer of stabilized tetragonal phase. It is found that the texture of the tetragonal layer determines the protectiveness of the oxide for corrosion. The transport of oxidizing species, such as anion defects, cation defects, and electron through the tetragonal oxide layer could be the rate limiting step of the corrosion. The defect diffusion can be affected by the growing stresses and microstructures such as grain boundaries and dislocations. In this work molecular dynamics simulations are used to investigate the anion and cation diffusion in bulk and at grain boundaries in tetragonal ZrO2. The results show that defect diffusion at grain boundaries is complex and the behavior strongly depends on the grain boundary type. For most of the grain boundaries studied the defect diffusion are much slower than in the bulk, implying that grain boundaries may not be fast defect transport paths during corrosion. The connection between the modeling results and published experimental work will also be discussed. This work is funded by the Laboratory Directed Research and Development (LDRD) program at Idaho National Laboratory.
Early-time free-surface flow driven by a deforming boundary
Brasz, C. Frederik; Arnold, Craig B.; Stone, Howard A.; Lister, John R.
2015-02-24
.6). The flow is driven by the boundary deformation, hb(x, t), given in (2.2). In partic- ular, we are interested in the velocity field and free-surface motion as the solid boundary approaches a steady state. 2.1. Nondimensionalization We nondimensionalize... . The axisymmetric domain-perturbation results showed similarly good agreement with simulations at ? = 0.05 and t = 20 across all values of ?; for brevity, these are not included here. The total kinetic energy in the axisymmetric simulations at t = 20 and ? = 0...
Non-modal analysis of the diocotron instability for cylindrical geometry with conducting boundary
Mikhailenko, V. V.; Seok Kim, Jin; Jo, Younghyun; June Lee, Hae; Mikhailenko, V. S.; Kharkiv National Automobile and Highway University, 61002 Kharkiv
2014-05-15
The temporal evolution of the linear diocotron instability of a cylindrical annular plasma column surrounded by a conducting boundary has been investigated by using the methodology of the cylindrical shearing modes. The linear solution of the initial and boundary-value problems is obtained which is valid for any time at which linear effects dominate. The solution reveals that the initial perturbations of the electron density pass through the stage of the non-modal evolution when the perturbation experiences spatio-temporal distortion pertinent to the considered geometry of the electron column. The result is confirmed by a two-dimensional cylindrical particle-in-cell simulation.
Tracking tumor boundary in MV-EPID images without implanted markers: A feasibility study
Zhang, Xiaoyong Homma, Noriyasu; Ichiji, Kei; Takai, Yoshihiro; Yoshizawa, Makoto
2015-05-15
Purpose: To develop a markerless tracking algorithm to track the tumor boundary in megavoltage (MV)-electronic portal imaging device (EPID) images for image-guided radiation therapy. Methods: A level set method (LSM)-based algorithm is developed to track tumor boundary in EPID image sequences. Given an EPID image sequence, an initial curve is manually specified in the first frame. Driven by a region-scalable energy fitting function, the initial curve automatically evolves toward the tumor boundary and stops on the desired boundary while the energy function reaches its minimum. For the subsequent frames, the tracking algorithm updates the initial curve by using the tracking result in the previous frame and reuses the LSM to detect the tumor boundary in the subsequent frame so that the tracking processing can be continued without user intervention. The tracking algorithm is tested on three image datasets, including a 4-D phantom EPID image sequence, four digitally deformable phantom image sequences with different noise levels, and four clinical EPID image sequences acquired in lung cancer treatment. The tracking accuracy is evaluated based on two metrics: centroid localization error (CLE) and volume overlap index (VOI) between the tracking result and the ground truth. Results: For the 4-D phantom image sequence, the CLE is 0.23 ± 0.20 mm, and VOI is 95.6% ± 0.2%. For the digital phantom image sequences, the total CLE and VOI are 0.11 ± 0.08 mm and 96.7% ± 0.7%, respectively. In addition, for the clinical EPID image sequences, the proposed algorithm achieves 0.32 ± 0.77 mm in the CLE and 72.1% ± 5.5% in the VOI. These results demonstrate the effectiveness of the authors’ proposed method both in tumor localization and boundary tracking in EPID images. In addition, compared with two existing tracking algorithms, the proposed method achieves a higher accuracy in tumor localization. Conclusions: In this paper, the authors presented a feasibility study of tracking tumor boundary in EPID images by using a LSM-based algorithm. Experimental results conducted on phantom and clinical EPID images demonstrated the effectiveness of the tracking algorithm for visible tumor target. Compared with previous tracking methods, the authors’ algorithm has the potential to improve the tracking accuracy in radiation therapy. In addition, real-time tumor boundary information within the irradiation field will be potentially useful for further applications, such as adaptive beam delivery, dose evaluation.
Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test
K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley
2004-03-01
The purpose of this work is to characterize groundwater flow and contaminant transport at the Shoal underground nuclear test through numerical modeling using site-specific hydrologic data. The ultimate objective is the development of a contaminant boundary, a model-predicted perimeter defining the extent of radionuclide-contaminated groundwater from the underground test throughout 1,000 years at a prescribed level of confidence. This boundary will be developed using the numerical models described here, after they are approved for that purpose by DOE and NDEP.
Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test
K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley
2004-03-01
Groundwater flow and radionuclide transport at the Shoal underground nuclear test are characterized using three-dimensional numerical models, based on site-specific hydrologic data. The objective of this modeling is to provide the flow and transport models needed to develop a contaminant boundary defining the extent of radionuclide-contaminated groundwater at the site throughout 1,000 years at a prescribed level of confidence. This boundary will then be used to manage the Project Shoal Area for the protection of the public and the environment.
Algebraic Bethe ansatz for the sl(2) Gaudin model with boundary
N. Cirilo António; N. Manojlovi?; E. Ragoucy; I. Salom
2015-02-10
Following Sklyanin's proposal in the periodic case, we derive the generating function of the Gaudin Hamiltonians with boundary terms. Our derivation is based on the quasi-classical expansion of the linear combination of the transfer matrix of the XXX Heisenberg spin chain and the central element, the so-called Sklyanin determinant. The corresponding Gaudin Hamiltonians with boundary terms are obtained as the residues of the generating function. By defining the appropriate Bethe vectors which yield strikingly simple off shell action of the generating function, we fully implement the algebraic Bethe ansatz, obtaining the spectrum of the generating function and the corresponding Bethe equations.
Gradient zone-boundary control in salt-gradient solar ponds
Hull, J.R.
1982-09-29
A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizeable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.
Boundary-induced orientation of dynamic filament networks and vesicle agglomerations
Philip Greulich; Ludger Santen
2011-06-28
We find a statistical mechanism that can adjust orientations of intracellular filaments to cell geometry in absence of organizing centers. The effect is based on random and isotropic filament (de-)polymerization dynamics and is independent of filament interactions and explicit regulation. It can be understood by an analogy to electrostatics and appears to be induced by the confining boundaries; for periodic boundary conditions no orientational bias emerges. Including active transport of particles, the model reproduces experimental observations of vesicle accumulations in transected axons.
N. F. Belmetsev; V. O. Bytev
2009-11-13
It has been found the exact solutions for nonstationary distribution of the temperature in the liquid ring with two viscosities and two free boundaries of the ring.
Jin, Y.J.; Lu, H., E-mail: shweld@sjtu.edu.cn; Yu, C.; Xu, J.J.
2013-10-15
Intergranular reheat cracking in the coarse-grained heat-affected zone of T23 steel was produced by strain to fracture tests on a Gleeble 3500 thermal–mechanical simulator. Then the grain boundary character, as well as the strain distribution after reheat crack propagation, was studied by electron backscatter diffraction technique. The results showed that incoherent ?3 boundaries were seldom found on the prior austenite grain boundaries. Therefore, only the type of random high-angle boundaries played a crucial role in the intergranular cracking. Microstructurally cavities and small cracks were preferentially initiated from high-angle grain boundaries. Low-angle grain boundaries and high-angle ones with misorientation angles less than 15° were more resistant to the cracking. More importantly, the fraction of high-angle grain boundaries increased with the plastic strain induced by both temperature gradient and stress in the coarse-grained heat-affected zone, which contributed to the crack initiation and propagation. Furthermore, the strain distributions in the vicinity of cavities and cracks revealed the accommodation processes of plastic deformation during stress relaxation. It also reflected the strength differences between grain interior and grain boundary at different heat-treated temperatures, which had a large influence on the cracking mechanism. - Highlights: • The coincidence site lattice boundaries play little role in the reheat cracking. • Cavity and crack occur at high-angle grain boundaries rather than low-angle ones. • The strain leads low-angle grain boundaries to transform to high-angle ones. • Strain distribution differs for cavity and crack zones at different temperatures.
Feenstra, Randall
1 Friedel Oscillation-Induced Energy Gap Manifested as Transport Asymmetry at Monolayer will first develop a general theory of the Friedel energy gap and the transport asymmetry across a boundary at the Fermi energy for electrons with wave vectors perpendicular to the interface. If the Friedel gaps on two
Impact of boundary conditions on entrainment and transport in gravity currents
Duan, Jinqiao
]. Gravity currents flowing down a sloping bottom that occur in the oceans (e.g., 0307-904X/$ - see front in turn is important in climate and weather studies. Oceanic gravity currents have been studied currents and the assumptions made in modeling them. Using ocean observations to develop realistic boundary
Cookies Along Trust-Boundaries (CAT): Accurate and Deployable Flood Protection
Akella, Aditya
Cookies Along Trust-Boundaries (CAT): Accurate and Deployable Flood Protection Martin Casado Aditya@google.com, shenker@icsi.berkeley.edu Abstract Packet floods targeting a victim's incoming bandwidth are no- toriously their applicability in practice. We propose CAT, a new network-based flood protection scheme. In CAT, all flows must
Well test imaging - a new method for determination of boundaries from well test data
Slevinsky, B.A.
1997-08-01
A new method has been developed for analysis of well test data, which allows the direct calculation of the location of arbitrary reservoir boundaries which are detected during a well test. The method is based on elements of ray tracing and information theory, and is centered on the calculation of an instantaneous {open_quote}angle of view{close_quote} of the reservoir boundaries. In the absence of other information, the relative reservoir shape and boundary distances are retrievable in the form of a Diagnostic Image. If other reservoir information, such as 3-D seismic, is available; the full shape and orientation of arbitrary (non-straight line or circular arc) boundaries can be determined in the form of a Reservoir Image. The well test imaging method can be used to greatly enhance the information available from well tests and other geological data, and provides a method to integrate data from multiple disciplines to improve reservoir characterization. This paper covers the derivation of the analytical technique of well test imaging and shows examples of application of the technique to a number of reservoirs.
T-duality trivializes bulk-boundary correspondence: some higher dimensional cases
Varghese Mathai; Guo Chuan Thiang
2015-11-14
Recently we introduced T-duality in the study of topological insulators, and used it to show that T-duality trivialises the bulk-boundary correspondence in 2 dimensions. In this paper, we partially generalise these results to higher dimensions and briefly discuss the 4D quantum Hall effect.
T-duality trivializes bulk-boundary correspondence: the parametrised case
Keith Hannabuss; Varghese Mathai; Guo Chuan Thiang
2015-11-01
We state a general conjecture that T-duality trivialises a model for the bulk-boundary correspondence in the parametrised context. We give evidence that it is valid by proving it in a special interesting case, which is relevant both to String Theory and to the study of topological insulators with defects in Condensed Matter Physics.
Extensions of mapping classes from the boundary of a Biringer san & Lecuire san
Paoluzzi, Luisa
Extensions of mapping classes from the boundary of a handlebody Biringer san & Lecuire san Biringer san & Lecuire san () Extensions of mapping classes 1 / 32 #12;Contents 1 Questions 2 Statements 3 Definitions 4 Outline of the proof 5 Yet unanswered questions 6 Biproduct of the proof Biringer san & Lecuire
Twinning partial multiplication at grain boundary in nanocrystalline Y. T. Zhu,1,a
Zhu, Yuntian T.
with medium-to-high stacking-fault energy have been observed to deform by twinning more easily than rebound mechanism,22 or the partial emissions from grain boundary.6 However, if a single twin grows from energy. It has been a long-standing puzzle on the origin of the twinning partials that lead
Stephens, Graeme L.
from infrared radiances Steven J. Cooper, Tristan S. L'Ecuyer, and Graeme L. Stephens Department inclusion of explicit cloud boundary information from complementary sensors as well as providing a suite of diagnostic tools for evaluating the dominant sources of uncertainty in all retrieved quantities. Errors
Boundary Helps: Efficient Routing Protocol using Directional Antennas in Cognitive Radio Networks
Wu, Jie
directions at the boundary area of a primary user. For every optional route between a source node, and piggybacks that information to the source node for route selection. However, it will cause a lot Ying Dai and Jie Wu Department of Computer and Information Sciences Temple University, Philadelphia, PA
Wave-driven wind jets in the marine atmospheric boundary layer
Reading, University of
Wave-driven wind jets in the marine atmospheric boundary layer Kirsty E. Hanley Stephen E. Belcher;Abstract The interaction between ocean surface waves and the overlying wind leads to a transfer of momentum can also be transferred upwards when long wavelength waves, characteristic of re- motely generated
Boundary Behavior of the GinzburgLandau Order Parameter in the Surface Superconductivity Regime
Recanati, Catherine
Boundary Behavior of the GinzburgLandau Order Parameter in the Surface Superconductivity Regime MLandau theory for a typeII superconductor in an applied magnetic field varying between the second and third of this energy expansion, which allows us to prove the desired uniformity of the surface superconductivity layer
eXtremes of heat conduction: Pushing the boundaries of the thermal
Braun, Paul
-called "nanofluids" (suspensions in liquids) polymer composites and coatings Fischer (2007) Lehman (2005) #12;Critical aspect ratio for a fiber composite · Isotropic fiber composite with high conductivity fibers (andeXtremes of heat conduction: Pushing the boundaries of the thermal conductivity of materials David
Butcher, Eric A.
an important role in applications of mechanical, aerospace and civil engineering. Studying the free vibrationFree Vibration Analysis of Kirchoff Plates with Damaged Boundaries by the Chebyshev Collocation Method Eric A. Butcher and Ma'en Sari Department of Mechanical and Aerospace Engineering, New Mexico
Boundary lubrication with a glassy interface Anal Lematre1,2
Carlson, Jean
Boundary lubrication with a glassy interface Anaël Lemaître1,2 and Jean Carlson1 1 Department lubrication. The model is based on a generalization of the shear transformation zone (STZ) theory, in which mea- surements on a microscopically thin layer of lubricant, sepa- rating atomically smooth (typically
Lidar Investigation of Tropical Nocturnal Boundary Layer Aerosols and Cloud Macrophysics
Manoj, M. G.; Devara, PC S.; Taraphdar, Sourav
2013-10-01
Observational evidence of two-way association between nocturnal boundary layer aerosols and cloud macrophysical properties under different meteorological conditions is reported in this paper. The study has been conducted during 2008-09 employing a high space-time resolution polarimetric micro-pulse lidar over a tropical urban station in India. Firstly, the study highlights the crucial role of boundary layer aerosols and background meteorology on the formation and structure of low-level stratiform clouds in the backdrop of different atmospheric stability conditions. Turbulent mixing induced by the wind shear at the station, which is associated with a complex terrain, is found to play a pivotal role in the formation and structural evolution of nocturnal boundary layer clouds. Secondly, it is shown that the trapping of energy in the form of outgoing terrestrial radiation by the overlying low-level clouds can enhance the aerosol mixing height associated with the nocturnal boundary layer. To substantiate this, the long-wave heating associated with cloud capping has been quantitatively estimated in an indirect way by employing an Advanced Research Weather Research and Forecasting (WRF-ARW) model version 2.2 developed by National Center for Atmospheric Research (NCAR), Colorado, USA, and supplementary data sets; and differentiated against other heating mechanisms. The present investigation as well establishes the potential of lidar remote-sensing technique in exploring some of the intriguing aspects of the cloud-environment relationship.
Measurements of stress fields near a grain boundary: Exploring blocked arrays of dislocations in 3D
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Guo, Y.; Collins, D. M.; Tarleton, E.; Hofmann, F.; Tischler, J.; Liu, W.; Xu, R.; Wilkinson, A. J.; Britton, T. B.
2015-06-24
The interaction between dislocation pile-ups and grain boundaries gives rise to heterogeneous stress distributions when a structural metal is subjected to mechanical loading. Such stress heterogeneity leads to preferential sites for damage nucleation and therefore is intrinsically linked to the strength and ductility of polycrystalline metals. To date the majority of conclusions have been drawn from 2D experimental investigations at the sample surface, allowing only incomplete observations. Our purpose here is to significantly advance the understanding of such problems by providing quantitative measurements of the effects of dislocation pile up and grain boundary interactions in 3D. This is accomplished throughmore »the application of differential aperture X-ray Laue micro-diffraction (DAXM) and high angular resolution electron backscatter diffraction (HR-EBSD) techniques. Our analysis demonstrates a similar strain characterization capability between DAXM and HR-EBSD and the variation of stress intensity in 3D reveals that different parts of the same grain boundary may have different strengths in resisting slip transfer, likely due to the local grain boundary curvature.« less
Subramanian, Venkat
Mathematical Model Reformulation for Lithium-Ion Battery Simulations: Galvanostatic Boundary of physics-based lithium-ion battery models to improve computational efficiency. While the additional steps, 2008. Published January 30, 2009. Mathematical modeling of lithium-ion batteries involves
Unique solutions to boundary value problems in the cold plasma model
Thomas H. Otway
2010-07-20
The unique existence of a weak solution to the homogeneous closed Dirichlet problem on certain D-star-shaped domains is proven for a mixed elliptic-hyperbolic equation. Equations of this kind arise in models for electromagnetic wave propagation in cold plasma. A related class of open boundary value problems is shown to possess strong solutions.
A HIGH ORDER NYSTROM METHOD FOR BOUNDARY INTEGRAL EQUATIONS ON AXISYMMETRIC SURFACES
Martinsson, Gunnar
. Whenever f can be represented with a moderate number of Fourier modes, the trans- formation of (1.1) to (1. Key words. boundary integral equations, high order discretization, body of revolution AMS subject of uncoupled small linear systems (one for each Fourier mode). Since the system matrices are dense, the gain
Physica A 385 (2007) 4658 Accumulating particles at the boundaries of a laminar flow
Schindler, Michael
2007-01-01
Physica A 385 (2007) 4658 Accumulating particles at the boundaries of a laminar flow Michael in stationary flows through channels of variable width at small Reynolds number. The combined influence for the particle density. It is shown that for extended spherical particles the shape of the fluid domain gives
Active Control of Instabilities in Laminar BoundaryLayer Flow--Part I: An Overview
Erlebacher, Gordon
Active Control of Instabilities in Laminar BoundaryLayer Flow-- Part I: An Overview Ronald D laminar flow in a region of the flow in which the natural instabilities, if left unattended, lead have been restricted to maintaining laminar flow through use of a technique termed ``wave cancellation
A REDUCED-BOUNDARY-FUNCTION METHOD FOR LONGITUDINAL SOLUTION DISPERSION IN SYMMETRIC CONFINED FLOWS
Xu Zhijie
2013-07-01
We present a reduced-boundary-function method for longitudinal solute transport in symmetric laminar flows. Flow is confined by two flat plates separated by a distance of 2a or by a tube with a radius of a (Figure 1). The standard advection-diffusion equation is mapped onto the boundary (r = a and r = 0, where r is the distance from the centerline shown in Figure 1). The original problem of solving c(x,r,t) is reduced to solve the solutions of c at the boundary, and the problem dimensionality is reduced from 3 to 2. Final results show that the boundary concentration ca(x,t) = c(x, r = a,t) is advected at the mean velocity with a dispersion equal to the molecular diffusion. The centerline concentration c0(x,t) = c(x,r = 0,t) is also advected at the mean velocity, but with a dispersion much larger than the Taylor dispersion. The cross-sectional average concentration is in agreement with the classical Taylor dispersion by neglecting higher order contributions. This study is relevant to the upscaling of solute transport.
Iceocean boundary conditions for coupled models Gavin A. Schmidt a,*, Cecilia M. Bitz b
for improving interoperability or modularity of climate system components from different groups (a central focus Mikolajewicz c , L.-Bruno Tremblay d a NASA Goddard Institute for Space Studies and Center for Climate Systems to revisit the boundary conditions at the sea iceocean interface to ensure that (a) mass and energy
A Reconstruction Procedure for Thermoacoustic Tomography in the Case of Limited Boundary Data
Steinhauer, Dustin
2009-01-01
We derive an explicit method for reconstructing singularities of the initial data in a thermoacoustic tomography problem, in the case of variable sound speed and limited boundary data. In order to obtain this explicit formula we assume the metric induced by the sound speed does not have conjugate points inside the region to be observed.
A Uniqueness Theorem for Thermoacoustic Tomography in the Case of Limited Boundary Data
Steinhauer, Dustin
2009-01-01
We prove a uniqueness theorem for compactly supported initial data for the variable speed wave equation arising in models of thermoacoustic tomography, given measurements on a part of the boundary. The proof is based on domain of dependence arguments and D. Tataru's unique continuation theorem.
A Navier boundary value problem for Willmore surfaces of Klaus Deckelnick
Grunau, Hans-Christoph
A Navier boundary value problem for Willmore surfaces of revolution Klaus Deckelnick and Hans (DFG) is gratefully acknowledged e-mail: Klaus.Deckelnick@ovgu.de e-mail: Hans of closed Willmore surfaces of prescribed genus was proved by Simon [Sn] and Bauer & Kuwert [BK]. Con
Boundary value problems for the one-dimensional Willmore equation Almost explicit solutions
Grunau, Hans-Christoph
Boundary value problems for the one-dimensional Willmore equation Â Almost explicit solutions Klaus. Existence of closed Willmore surfaces of prescribed genus has been proved by Simon [Sn] and Bauer & Kuwert [BK]. Also, local and global existence results for the e-mail: Klaus
Wind Energy-Related Atmospheric Boundary Layer Large-Eddy Simulation Using OpenFOAM: Preprint
Churchfield, M.J.; Vijayakumar, G.; Brasseur, J.G.; Moriarty, P.J.
2010-08-01
This paper develops and evaluates the performance of a large-eddy simulation (LES) solver in computing the atmospheric boundary layer (ABL) over flat terrain under a variety of stability conditions, ranging from shear driven (neutral stratification) to moderately convective (unstable stratification).
NUMERICAL TREATMENT OF REALISTIC BOUNDARY CONDITIONS FOR THE EDDY CURRENT PROBLEM IN AN
RodrÃguez, Rodolfo
NUMERICAL TREATMENT OF REALISTIC BOUNDARY CONDITIONS FOR THE EDDY CURRENT PROBLEM IN AN ELECTRODE methods to solve the eddy current problem in a conducting bounded domain. In particular, we consider-frequency harmonic Maxwell equations, eddy current problems, finite element computational electromagnetism, Lagrange
Numerical solution of eddy current problems in bounded domains using realistic boundary
RodrÃguez, Rodolfo
Numerical solution of eddy current problems in bounded domains using realistic boundary conditions-called eddy currents. The problem is formulated in terms of the magnetic field. This formulation in a metallurgical arc furnace. Key words: low-frequency harmonic Maxwell equations, eddy current problems, finite
Hansen, James E.
conditions is of paramount importance. The Kyoto Protocol was doomed to failure because fossil fuel boundary of their control, as the planet heads inexorably toward an ice-free state. A critical fact is the long lifetime a portion of the fossil fuels that will be left in the ground, or captured upon emission and put back
Boundary conditions a non-trivial role solution partial di erential
a Poisson equation with # e#11;ective source term. Using Faraday's show that axisymmetry presents unusual modeling fusion plasmas [2,3]. example is perfectly conducting wall, ideal, boundary condition nonlinear;eld # # # # # standard choice # based single wire model, ## # # # = # # #In dimensionless form (scale
Explicit Representation of Main-Chamber Recycling in the OEDGE Boundary Code
Stangeby, P. C.
Explicit Representation of Main-Chamber Recycling in the OEDGE Boundary Code S. LISGO, P contact occurs with the main chamber walls, additional to the divertor target. In order to investigate the role of main chamber recycling on core fuelling and impurity behavior, the OSM-EIRENE- DIVIMP (OEDGE
California at Berkeley, University of
Outer radiation belt boundary location relative to the magnetopause: Implications for magnetopause fluxes of the outer radiation belt often decrease rapidly in response to solar wind disturbances. If the MPS is essential for outer radiation belt electron losses, a close relationship between the outer edge
Numerical Solution of a Free-Boundary Problem for Percussive Deep Drilling Modeling by BEM
Mikhailov, Sergey
Numerical Solution of a Free-Boundary Problem for Percussive Deep Drilling Modeling by BEM S to a stationary-periodic quasi-static model of rock percus- sive deep drilling is presented. The rock is modeled. An auxiliary problem of stationary inden- tation of a rigid drill bit is considered first, where it is assumed
Non-hypersingular boundary integral equations for 3-D non-planar crack dynamics
Madariaga, RaÃºl
Non-hypersingular boundary integral equations for 3-D non-planar crack dynamics T. Tada, E, are removed by way of a technique of regu- larization based on integration by parts. The variables are denoted, in time and space, of the slip along the crack and a set of integration kernels. Then a limiting process
HOW TO DISPATCH OBSERVERS TO TRACK AN EVOLVING BOUNDARY Tingting Jiang and Carlo Tomasi
Tomasi, Carlo
it necessary to dispatch a limited number of observers (ships, vehicles, or air- planes with cameras; field boundary of a large phenomenon such as an oil spill, a fire, a hurricane, air or water pollution, or EL Ni. Water currents, temperatures, or pollution levels are recorded over vast areas by vessels or movable
ORIGINAL ARTICLE GPS snow sensing: results from the EarthScope Plate Boundary
Larson, Kristine
ORIGINAL ARTICLE GPS snow sensing: results from the EarthScope Plate Boundary Observatory Kristine and by water supply managers to predict/mitigate drought and flood conditions. Existing in situ snow sensors/networks lack the necessary spatial and temporal sensitivity. Satellite measurements currently assess snow cover
Market Structure, Internal Capital Markets, and the Boundaries of the Firm
Aazhang, Behnaam
, but this flexibility comes at a cost: integrated firms cannot commit to particular capital allocations in advanceMarket Structure, Internal Capital Markets, and the Boundaries of the Firm Richmond D. Mathews an internal capital market. An internal capital market provides resource flexibility but does not allow
M. Ostrowski; R. Schlickeiser
1996-04-18
In the present paper we discuss the modifications introduced into the first-order Fermi shock acceleration process due to a finite extent of diffusive regions near the shock or due to boundary conditions leading to an increased particle escape upstream and/or downstream the shock. In the considered simple example of the planar shock wave we idealize the escape phenomenon by imposing a particle escape boundary at some distance from the shock. Presence of such a boundary (or boundaries) leads to coupled steepening of the accelerated particle spectrum and decreasing of the acceleration time scale. It allows for a semi-quantitative evaluation and, in some specific cases, also for modelling of the observed steep particle spectra as a result of the first-order Fermi shock acceleration. We also note that the particles close to the upper energy cut-off are younger than the estimate based on the respective acceleration time scale. In Appendix A we present a new time-dependent solution for infinite diffusive regions near the shock allowing for different constant diffusion coefficients upstream and downstream the shock.
THE ECOLOGICAL BOUNDARIES OF SIX CAROLINA BAYS: COMMUNITY COMPOSITION AND ECOTONE DISTRIBUTION
Hutchens, John
of Biology P.O. Box 261954 Coastal Carolina University Conway, South Carolina, USA 29528-6054 E-mail: Joluken rims of each of six Carolina bays in northeastern South Carolina to characterize the community gradientTHE ECOLOGICAL BOUNDARIES OF SIX CAROLINA BAYS: COMMUNITY COMPOSITION AND ECOTONE DISTRIBUTION
Digital Control Strategy for Multi-Phase Interleaved Boundary Mode and DCM Boost PFC Converters
Noé, Reinhold
Digital Control Strategy for Multi-Phase Interleaved Boundary Mode and DCM Boost PFC Converters T switching frequency, DCM boost PFC converter can be operated with constant as well as with variable.schafmeister@delta-es.com Abstract-- A digital control strategy which provides optimal interleaving of multi-phase boost power factor
nanotechnology DIME Workshop "Industrial innovation dynamics and knowledge characteristics, exploring systems. Using nanotechnology as a case the paper focuses on analysing boundary spanning effects to capture possible changes in the knowledge base and search modes related to the rise of nanotechnology
Spiga, Aymeric
Elements of comparison between Martian and terrestrial mesoscale meteorological phenomena Keywords: Mesoscale meteorology Katabatic winds Boundary layer convection Comparative planetology a b s t r a c t Terrestrial and Martian atmospheres are both characterised by a large variety of mesoscale
Scattered waves from low-frequency earthquakes and plate boundary structure in northern Cascadia
Nowack, Robert L.
et al., 2012], a region with generally low levels of regular seismicity, has afforded a new source of seismic energy with which to interro- gate plate boundary structure. We review constraints on plate to northern Vancouver Island, and from some tens of kilometers seaward of the coast to depths in excess of 40
Ergodicity and Energy Distributions for Some Boundary Driven Integrable Hamiltonian Chains
Young, Lai-Sang
. Email: klin@math.arizona.edu 3 Courant Institute of Mathematical Sciences, New York University, New York energy with the site, then turns around and moves away at a speed equal to the square root of its newErgodicity and Energy Distributions for Some Boundary Driven Integrable Hamiltonian Chains Peter
West, David Edward
2014-12-12
) was unexpectedly farther aft than the polished. Transport unit Reynolds numbers were achieved using a Cessna O-2A Skymaster. Infrared thermography, coupled with a post-processing code, was used to globally extract a quantitative boundary-layer transition location...
Simulating the Motion of Flexible Pulp Fibres Using the Immersed Boundary Method
Stockie, John
of elds, including reinforced composite materials,biotechnology and the pulp and paper industry is extremely important to the pulp and paper industry in many stages of the papermaking process. The outputSimulating the Motion of Flexible Pulp Fibres Using the Immersed Boundary Method Submitted to J
for the international paper and pulp industry (Turnbull 2000). The trees are propagated extensively as exoticsFULL PAPER DNA sequence incongruence and inconsistent morphology obscure species boundaries plantation industry in the sub- tropical and tropical areas of Australia (Andjic et al.
The effect of reconnection on the structure of the Sun's open-closed-flux boundary
Pontin, D I
2015-01-01
Global magnetic field extrapolations are now revealing the huge complexity of the Sun's corona, and in particular the structure of the boundary between open and closed magnetic flux. Moreover, recent developments indicate that magnetic reconnection in the corona likely occurs in highly fragmented current layers, and that this typically leads to a dramatic increase in the topological complexity beyond that of the equilibrium field. In this paper we investigate the consequences of reconnection at the open-closed flux boundary ("interchange reconnection") in a fragmented current layer. We demonstrate that it leads to a situation in which magnetic flux (and therefore plasma) from open and closed field regions is efficiently mixed together. This corresponds to an increase in the length and complexity of the open-closed boundary. Thus, whenever reconnection occurs at a null point or separator of the open-closed boundary, the associated separatrix arc of the so-called "S-web" in the high corona becomes not a single ...