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673 results on '"Taylor, D. E."'

1. Groups with at most 13 nonpower subgroups

Author

Zheng, Jiwei, Zhou, Wei, and Taylor, D. E.

Subjects
Mathematics - Group Theory, 20D25, 20D60
Abstract

For a group G and positive interger m, Gm denotes the subgroup generated by the elements gm where g runs through G. The subgroups not of the form Gm are called nonpower subgroups. We extend the classification of groups with few nonpower subgroups from groups with at most 9 nonpower subgroups to groups with at most 13 nonpower subgroups., Comment: 16 pages, 0 figures

Published
2023

2. Cratering of Soil by Impinging Jets of Gas, with Application to Landing Rockets on Planetary Surfaces

Author

Metzger, Philip T., Vu, Bruce T., Taylor, D. E., Kromann, M. J., Fuchs, M., Yutko, B., Dokos, Adam, Immer, Christopher D., Lane, John E., Dunkel, M. B., Donahue, Carly M., and Latta III, Robert C.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Condensed Matter - Statistical Mechanics, Physics - Fluid Dynamics
Abstract

Several physical mechanisms are involved in excavating granular materials beneath a vertical jet of gas. These occur, for example, beneath the exhaust plume of a rocket landing on the soil of the Moon or Mars. A series of experiments and simulations have been performed to provide a detailed view of the complex gas/soil interactions. Measurements have also been taken from the Apollo lunar landing videos and from photographs of the resulting terrain, and these help to demonstrate how the interactions extrapolate into the lunar environment. It is important to understand these processes at a fundamental level to support the on-going design of higher-fidelity numerical simulations and larger-scale experiments. These are needed to enable future lunar exploration wherein multiple hardware assets will be placed on the Moon within short distances of one another. The high-velocity spray of soil from landing spacecraft must be accurately predicted and controlled lest it erosively damage the surrounding hardware., Comment: 6 pages, 5 figures

Published
2021

3. Normalisers of parabolic subgroups in finite unitary reflection groups

Author

Krishnasamy, Muraleedaran and Taylor, D. E.

Subjects
Mathematics - Group Theory, 20F55
Abstract

It is well known that the normaliser of a parabolic subgroup of a finite Coxeter group is the semidirect product of the parabolic subgroup by the stabiliser of a set of simple roots. We show that a similar result holds for all finite unitary reflection groups: namely, the normaliser of a parabolic subgroup is a semidirect product and in many, but not all, cases the complement can be obtained as the stabiliser of a set of roots. In addition we record when the complement acts as a reflection group on the space of fixed points of the parabolic subgroup., Comment: 23 pages, 14 tables

Published
2017
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4. GROUPS WITH FEW NONPOWER SUBGROUPS.

Author

ZHENG, JIWEI, ZHOU, WEI, and TAYLOR, D. E.

Subjects
COUNTING
Abstract

For a group G and $m\ge 1$ , let $G^m$ denote the subgroup generated by the elements $g^m$ , where g runs through G. The subgroups not of the form $G^m$ are the nonpower subgroups of G. We classify the groups with at most nine nonpower subgroups. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Simple extensions of reflection subgroups of primitive complex reflection groups

Author

Taylor, D. E.

Subjects
Mathematics - Group Theory, 20F55
Abstract

If $G$ is a finite primitive complex reflection group, all reflection subgroups of $G$ and their inclusions are determined up to conjugacy. As a consequence, it is shown that if the rank of $G$ is $n$ and if $G$ can be generated by $n$ reflections, then for every set $R$ of $n$ reflections which generate $G$, every subset of $R$ generates a parabolic subgroup of $G$., Comment: 17 pages, 20 tables

Published
2012
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7. Explicit irreducible representations of the Iwahori-Hecke algebra of type $F_4$

Author

Ram, Arun and Taylor, D. E.

Subjects
Mathematics - Representation Theory, Mathematics - Quantum Algebra
Abstract

A general method for computing irreducible representations of Weyl groups and Iwahori-Hecke algebras was introduced earlier by the first author. The representations of the algebras of types $A_n$, $B_n$, $D_n$ and $G_2$ were computed and it is the purpose of this paper to extend these computations to $F_4$. The main goal here is to compute irreducible representations of the Iwahori-Hecke algebra of type $F_4$ by only using information in the character table of the Weyl group.

Published
1997

14. Cratering Soil by Impinging Jets of Gas, with Application to Landing Rockets on Planetary Surfaces

Author

Metzger, Philip T, Vu, B. T, Taylor, D. E, Kromann, M. J, Fuchs, M, Yutko, B, Dokos, A, Immer, Christopher D, Lane, J. E, Dunkel, Michael B, Donahue, Carly M, and Latta, R. C., III

Subjects
Lunar And Planetary Science And Exploration
Abstract

Several physical mechanisms are involved in excavating granular materials beneath a vertical jet of gas. These occur, for example, beneath the exhaust plume of a rocket landing on the soil of the Moon or Mars. A series of experiments and simulations have been performed to provide a detailed view of the complex gas/soil interactions. Measurements have also been taken from the Apollo lunar landing videos and from photographs of the resulting terrain, and these help to demonstrate how the interactions extrapolate into the lunar environment. It is important to understand these processes at a fundamental level to support the ongoing design of higher-fidelity numerical simulations and larger-scale experiments. These are needed to enable future lunar exploration wherein multiple hardware assets will be placed on the Moon within short distances of one another. The high-velocity spray of soil from landing spacecraft must be accurately predicted and controlled lest it erosively damage the surrounding hardware.

Published
2007

15. Abstract form for the Irish Journal of Medical Science v workshop on gastroduodenal pathology and Helicobacter pylori July 5th — 7th 1992 — Dublin, Ireland

Author

Logan, R. P. H., Gummett, P. A., Walker, M. M., Karim, Q. N., Baron, J. H., Misiewicz, J. J., Trieber, G., Walker, S., Klotz, U., Lozniewski, A., Weber, M., de Korwin, J. D., Floquet, J., Conroy, M. C., Burdin, J. C., Mannes, G. A., Bayerdörffer, E., Höchter, W., Weingart, J., Heldwein, W., Sommer, A., Müller-Lissner, S., Bomschein, W., Miehlke, S., Weinzierl, M., Ruckdeschel, G., von Wulffen, H., Köpcke, W., Stolte, M., Rune, S. J., Justesen, T., Hansen, J. M., Jensen, T. G., Eriksen, J., Thomsen, O. ø., Scheibel, J., Bonnevie, O., Bremmelgaard, A., Vilien, M., Knuhtsen, S., Elsborg, L., Hansen, J., Lauritsen, K., Wulff, H. R., Boixeda, D., Ballestero, S., Cantón, R., De Rafael, L., Martinm de Argila, C., Pozuelo, M. J., Sampedro, J., Baquero, F., Grigoriev, P. Ya., Isakov, V. A., Iakovenko, E. P., Hirschl, A. M., Brandstätter, G., Dragosics, B., Hentschel, E., Kundi, M., Rotter, M. L., Schütze, K., Taufer, M., Neri M, Susi D, Bovani I, Pindo R, Cuccurullo F., Coelho, L. G. V., Passos, M. C. F., Chausson, Y., Vieira, W. L. S., Castro, F. J., Franco, J. M. M., Fernandes, M. L. M., Castro, L. P., Jonas, C., De Koster, E., Van Gossum, M., Depierreux, M., Cheval, M., Deltenre, M., Schütz, E., Bethke, B., Lee, A., Hegedus, E., O’Rourke, J., Larsson, H., Sjöstedt, S., Veress, B., Nord, C. E., Sobala, G. M., George, R., Tompkins, D., Finlay, J., Manning, A., Sant, S., Xia, H. X., Daw, M., Gilvarry, J., Keane, C. T., O’Morain, C., Rubio, M. A., Hegarty, B., Blum, A. L., Sulser, E., Stadelmann, O., Munoz, N., Buiatti, E., Vivas, J., Oliver, W., Cano, E., Peraza, S., Castro, D., Sanchez, V., Andrade, O., Benz, M., Mendz, G. L., Hazell, S. L., Salmela, K. S., Roire, R. P., Hook-Nikanne, J., Kosunen, T. U., Salaspur, M., Luke, C. J., Reynolds, D. D. J., Penn, C. W., Bode, G., Mauch, F., Ditschuneit, H., Malfertheiner, P., Ferrero, Richard L., Agnes Labigne, Eaton, K. A., Krakowka, S., Mobley, H. L. T., Hu, Li-Tai, Foxall, P. A., Moran, A. P., Helander, I. M., Altman, C., Sobhani, I., Vissugaire, C., Migrant, M., Etienne, J. P., Sommi, P., Ricci, V., Fiocca, R., Cova, E., Figura, N., Romano, M., Ivey, K. J., Solcia, E., Ventura, U., Nilius, M., Schieffer, S., Hengels, K. J., Jablonowski, H., Strohmeyer, G., Cabrai, M. D., Barbosa, A. J. A., Lima Hr., G. F., Oliveira, C. A., Polak, J. M., Oderda, G., Villani, L., Altare, F., Morra, I., Miserendino, L., Ansaldi, N., Dixon, M. F., Wyatt, J. I., Axon, A. T. R., Beattie, S., Hamilton, H., Shabib, S., Cutz, E., Drumm, B., Sherman, P., Noach, L. A., Rolf, T., Bosma, N. B., Schwartz, M. P., Oosting, J., Rauws, E. A. J., Tytgat, G. N. J., Andrew, A., Nardone, G., d’Ormiento, F., Pontillo, M., Lobo, A. J., Uff, J. S., McNulty, C. N. M., Wilkinson, S. P., Suriani, R., Pallante, C., Ravizza, M., Galliano, D., Sallio, D., Malandrino, M., Oneglio, R., Colozza, M., Mazzucco, D., Gaia, E., Eidt, S., Vincent, P., Gottrand, F., Turck, D., Lecomte-Houcke, M., Leclerc, H., Bonvicini, F., Pretolani, S., Baraldini, M., Cilla, D., Baldinelli, S., Bazocchi, E., Acampora, P., Careddu, N., Brocchi, E., Gasbarrini, G., Joubert, M., Bazin, N., Thiaucourt, D., Protte, E., Gissler, C., Duprez, A., Merlin, P., Forestier, S., Labenz, J., Gyenes, E., Rühl, G. H., Börsch, G., Daskalopoulos, G., Carrick, J., Lian, R., Wagner, S., Bleck, J., Gebel, M., Bär, W., Manns, M., Lamouliatte, H., Bernard, P. H., Cayla, R., Vialette, G., Quinton, A., Mégraud, F., Lemaire, M., Quinten, A., De Mascarel, A., Webb, P., Forman, D., Knight, T., Wilson, A., Graves, S., Newell, D., Elder, J., Tonelli, E., Gatte, M. R. A., Ghironzi, G. C., Giulianelli, G., Bamford, K. B., Collins, J. S. A., Bickley, J., Johnston, B. T., Potts, S., Boston, V., Owen, R. J., Sloan, J., Basso, L., Lawlor, S., Clune, J., Szelényi, H., Stohmeyer, G., Macedo, G., Iglésias, I., Chaves, A. P., Loureiro, A., Katelaris, P. H., Seow, F., Lin, B., Napoli, J., Hones, D. B., Ngu, M. C., Akopyantz, Natalia S., Bukanov, Nikolay O., Westblom, T. Ulf, Berg, Douglas E., Nyst, J. F., Denis, P., Buset, M., De Reuck, M., Nielsen, H., Andersen, L. P., Birkholz, Sabine, Knipp, Ulrich, Nietzki, Claudia, Opferkuch, Wolfgang, Crabtree, J. E., Peichl, P., Lindly, I. J. D., Deusch, K., Seifirth, C., Funk, A., Dahie, I., Reut, K., Classen, M., Gionchetti, P., Vaira, D., Campieri, M., Bertinelli, E., Menegatti, M., Belluzzi, A., Briognola, C., Miglioli, M., Barbara, L., Tommaso, A. Di, Magistris, M. T. De, Bugnoli, M., Petracca, R., Covacci, A., Censini, S., Rappuoli, R., Abrignani, S., Territo, M. C., Smela, K. L., Reeve, J. R., Lee, T. D., Walsh, J. H., Armellini, D., Crabtree, J. E., Xiang, Z. Y., Mitchell, H. M., Hu, P. J., Li, Y. Y., Wang, Z. J., Zhao, S. M., Liu, Q., Chen, M., Du, G. G., Filipe, M. I., Reed, P. I., Craanen, M. E., Blok, P., Dekker, W., Colombo, E., Redaelli, D., Santangelo, M., Spinelli, M., Farinati, F., Valiante, F., Delia Libera, G., Germanà, B., Baffa, R., Rugge, M., Vianelo, F., Di Mario, F., Sipponen, Pentti, Rokkas, T., Popotheodorou, G., Kaldgeropoulos, N., Deprez, C., Galand, P., Fox, J. G., Wishnok, P., Murphy, J. C., Tannenbaum, S., Correa, P., Parsonnet, Julie, Macor, C., Da Broi, G. L., Avellinio, C., Reifen, R., Rasooly, I., Millson, M. E., Murphy, K., Thomas, J. E., Eastham, E. J., Malorgio, E., Dell’Olio, D., Kemmer, T. P., Dominguez-Munoz, J. E., Klingel, H., Gatto, M. R. A., Olivieri, R., Bayeli, R. F., Abate, L., De Gregorio, L., Aziz, J., Esposito, E., Basagni, C., Guilluy, R., Rousseau-Tsangaris, M., Brazier, J. L., Wadstiöm, Torkel, Tyszkiewicz, Tadeusz, Bergenzaun, Per, Olsson, Karin, Birac, C., Tall, F., Albenque, M., Labigne, A., Megraud, F., Feldman, R. A., Deeks, J., Glupczynski, Y., Burette, A., Goossens, H., Van den Boore, C., Butzler, J. P., Veldhuyzen van Zanten, S., Best, L., Benzanson, G., Haldane, D., Hazell, S., Mapstone, N. P., Lynch, D. A. F., Quirke, P., Taylor, D. E., Chang, N., Eaton, M., Stockdale, E., Salama, S. M., Thompson, L., Cockayne, A., Spiller, R. C., Leen, E., Sweeney, E., Klann, H., Hatz, R., Bornschein, W., Simon, T., Eimiller, A., Bolle, F., Schweikert, C., Köpeke, W., Moss, S. F., Bishop, A. E., Calam, J., Cahill, R. J., Xia, H., Solnick, J., and Tompkins, L.

Published
1992
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19. Density functional theory and evolution algorithm calculations of elastic properties of AION.

Author

Batyrev, I. G., Taylor, D. E., Gazonas, G. A., and McCauley, J. W.

Subjects
*ALUMINUM oxynitride spinel, *DENSITY functional theory, *EVOLUTIONARY algorithms, *ELASTICITY, *PHYSICS research
Abstract

Different models for aluminum oxynitride (AION) were calculated using density functional theory and optimized using an evolutionary algorithm. Evolutionary algorithm and density functional theory (DFT) calculations starting from several models of AION with different Al or O vacancy locations and different positions for the N atoms relative to the vacancy were carried out. The results show that the constant anion model [McCauley et al., J. Eur. Ceram. Soc. 29(2), 223 (2009)] with a random distribution of N atoms not adjacent to the Al vacancy has the lowest energy configuration. The lowest energy structure is in a reasonable agreement with experimental X-ray diffraction spectra. The optimized structure of a 55 atom unit cell was used to construct 220 and 440 atom models for simulation cells using DFT with a Gaussian basis set. Cubic elastic constant predictions were found to approach the experimentally determined AlON single crystal elastic constants as the model size increased from 55 to 440 atoms. The pressure dependence of the elastic constants found from simulated stress-strain relations were in overall agreement with experimental measurements of polycrystalline and single crystal AlON. Calculated IR intensity and Raman spectra are compared with available experimental data. [ABSTRACT FROM AUTHOR]

Published
2014
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33. Lipopolysaccharide structures of Helicobacter pylori genomic strains 26695 and J99, mouse model H. pylori Sydney strain, H. pylori P466 carrying sialyl Lewis X, and H. pylori UA915 expressing Lewis B

Author

Monteiro, M. A., Appelmelk, B. J., Rasko, D. A., Moran, A. P., Hynes, S. O., MacLean, L. L., Chan, K. H., Michael, F. S., Logan, S. M., O'Rourke, J., Lee, A., Taylor, D. E., and Perry, M. B.

Subjects
glycotypes, Helicobacter pylori, lipopolysaccharide, histo-blood groups
Abstract

This study describes the molecular makeup of the cell-wall lipopolysaccharides (LPSs) (O-chain polysaccharide→core oligosaccharide→lipid A) from five Helicobacter pylori strains: H. pylori 26695 and J99, the complete genome sequences of which have been published, the established mouse model Sydney strain (SS1), and the symptomatic strains P466 and UA915. All chemical and serological experiments were performed on the intact LPSs. H. pylori 26695 and SS1 possessed either a low-Mr semi-rough-form LPS carrying mostly a single Ley type-2 blood-group determinant in the O-chain region covalently attached to the core oligosaccharide or a high-Mr smooth-form LPS, as did strain J99, with an elongated partially fucosylated type-2 N-acetyllactosamine (polyLacNAc) O-chain polymer, terminated mainly by a Lex blood-group determinant, connected to the core oligosaccharide. In the midst of semi-rough-form LPS glycoforms, H. pylori 26695 and SS1 also expressed in the O-chain region a difucosylated antigen, α-l-Fucp(1–3)-α-l-Fucp(1–4)-β-d-GlcpNAc, and the cancer-cell-related type-1 or type-2 linear B-blood-group antigen, α-d-Galp(1–3)-β-d-Galp(1–3 or 4)-β-d-GlcpNAc. The LPS of H. pylori strain P466 carried the cancer-associated type-2 sialyl Lex blood-group antigen, and the LPS from strain UA915 expressed a type-1 Leb blood-group unit. These findings should aid investigations that focus on identifying and characterizing genes responsible for LPS biosynthesis in genomic strains 26695 and J99, and in understanding the role of H. pylori LPS in animal model studies. The LPSs from the H. pylori strains studied to date were grouped into specific glycotype families.

Published
2001

35. First principles calculation of stress induced amorphization in armor ceramics

Author

Taylor, D. E. and Taylor, D. E.

Subjects
Armor., Ceramic materials., Boron compounds., Carbides., Boron Compounds, Matériaux céramiques., Bore Composés., Carbures., Armor., Boron compounds., Carbides., Ceramic materials.
Abstract

Recent experimental work within the U.S. Army Research Laboratory has identified the formation of nanoscale-sized intragranular amorphous bands leading to a marked reduction in ballistic performance of boron carbide (B4C). This pressureinduced amorphization has been examined through application of the Born stability criterion that imposes restrictions on the relative magnitudes of the elastic constants of a stable crystal. The analysis has been conducted for B4C as a function of structural polytype using ab initio solid-state density functional methods and the results of the pressure evolution of the B4C elastic constants are reported. It is shown that the C-C-C polytype, a minority phase in the B4C lattice, fails at a pressure of =20 gigapascals less than the other polytypes tested in this survey, indicating that it may serve as one of the initial points of failure upon impact.

Published
2011

40. Velocities of fragments from bursting gas reservoirs.

Author

Taylor, D. E and Price, C. F

Subjects
Structural Mechanics
Abstract

A solution is obtained from a simplified approach for the problem of the motion of two fragments driven into a vacuum after rupture of a container filled with gas. Following rupture, the two container fragments are driven in opposite directions. From the separation developed between the moving fragments, the originally contained gas escapes to the vacuum, perpendicular to the direction of motion of the fragments, and with locally sonic velocity. The present solution removes two restrictions of an earlier similar approach: (1) the speed of the gas within the original volume (and consequently, by inference, that of the fragments) is small relative to the sonic escape velocity, and (2) the volume between the separating fragments while they are accelerating undergoes negligible change from the original volume.

Published
1971

41. Multilaboratory Comparison of Proficiencies in Susceptibility Testing of Helicobacter pylori and Correlation between Agar Dilution and E Test Methods

Author

Best, L. M., primary, Haldane, D. J. M., additional, Keelan, M., additional, Taylor, D. E., additional, Thomson, A. B. R., additional, Loo, V., additional, Fallone, C. A., additional, Lyn, P., additional, Smaill, F. M., additional, Hunt, R., additional, Gaudreau, C., additional, Kennedy, J., additional, Alfa, M., additional, Pelletier, R., additional, and Veldhuyzen van Zanten, S. J. O., additional

Published
2003
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45. Investigationsof the Intermolecular Forces betweenRDX and Polyethylene by Force–Distance Spectroscopy and MolecularDynamics Simulations.

Author

Taylor, D. E., Strawhecker, K. E., Shanholtz, E. R., Sorescu, D. C., and Sausa, R. C.

Subjects
*CYCLOHEXANE, *POLYETHYLENE, *INTERMOLECULAR forces, *BINDING energy, *CRYSTAL structure, *MOLECULAR dynamics
Abstract

The development of novel nanoenergeticmaterials with enhancedbulk properties requires an understanding of the intermolecular interactionsoccurring between molecular components. We investigate the surfaceinteractions between 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX)and polyethylene (PE) crystals on the basis of combined use of moleculardynamics (MD) simulations and force–distance spectroscopy,in conjunction with Lifshitz macroscopic theory of van der Waals forcesbetween continuous materials. The binding energy in the RDX–PEsystem depends both on the degree of PE crystallinity and on the RDXcrystal face. Our MD simulations yield binding energies of approximately132 and 120 mJ/m2for 100% amorphous and 100% crystallinePE on RDX (210), respectively. The average value is about 36% greaterthan our experimental value of 81 ± 15 mJ/m2for PE(∼48% amorphous) on RDX (210). By comparison, Liftshitz theorypredicts a value of about 79 mJ/m2for PE interacting withRDX. Our MD simulations also predict larger binding energies for bothamorphous and crystalline PE on RDX (210) compared to the RDX (001)surface. Analysis of the interaction potential indicates that about60% of the binding energy in the PE–RDX system is due to attractiveinteractions between HPE–ORDXand CPE–NRDXpairs of atoms. Further, amorphousPE shows a much longer interaction distance than crystalline PE withthe(210) and (001) RDX surfaces due to the possibility of larger polymerelongations in the case of amorphous PE as strain is applied. Also,we report estimates of the binding energies of energetic materialsRDX and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) withPE, propylene, polystyrene, and several fluorine-containing polymersusing Lifshitz theory and compare these with reported MD calculations. [ABSTRACT FROM AUTHOR]

Published
2014
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