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3. Convolution Model for the Structure Functions of the Nucleon

Author

Keppler, J. and Hofmann, H. M.

Subjects
High Energy Physics - Phenomenology, Nuclear Theory
Abstract

We start from an MIT-bag model calculation which provides information about the constituent quark distributions in the nucleon. The constituent quarks, however, are themselves considered as complex objects whose partonic substructure is resolved in deep inelastic scattering. This gives rise to structure functions of the constituent quarks which, in the unpolarized case, are fitted to data at a fixed scale employing three model parameters. Using $Q^{2}$--evolution equations the data are also well described at other scales. For the spin\-dependent struc\-ture func\-tions $g_{1}^{p,n}$ we additionally have to introduce polar\-izat\-ion functions for valence and sea quarks which are determined by exploiting the $x$--dependence of the available proton data only. A negatively polarized sea in the range $x\geq 0.01$ is suggested. We are then capable of predicting the shape of the neutron structure function $g_{1}^{n}$ which turns out to be in good agreement with experiment. Finally we present an estimate for the trans\-versely polarized structure function $g_{2}$, offering the possibility of extrac\-ting the twist--3 con\-tri\-bution and rating its importance., Comment: email: keppler@faupt31.physik.uni-erlangen.de, 21 pages LATEX, 12 figures added in PostScript format (should be stripped off before latexing), KH-TP3-ER-94-02

Published
1994

4. The Spin Structure of the Proton in a Non-relativistic Quark Model

Author

Keppler, J. and Hofmann, H. M.

Subjects
High Energy Physics - Phenomenology, Nuclear Theory
Abstract

The spin structure of the proton is investigated in the framework of an extended quark potential model which in addition to the conventional $3q$--structure also takes into account $(3q)(q\bar q)$--admixtures in the proton wave function. For reasons of parity such admixtures contain an odd orbital angular momentum thus allowing the proton spin to be shared among quark spins and orbital angular momenta. We show that only certain admixtures are suited for a significant reduction of the quark spin content of the proton as suggested by the EMC--result. Within a Hamiltonian model quark spin contributions to the proton spin down to $0.5$ can be reproduced easily., Comment: email: keppler@faupt31.physik.uni-erlangen.de, 9 pages REVTEX, 1 figure added as PostScript-file which should be stripped off before texing

Published
1994
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6. Determination of specific and non-specific protein–protein interactions for beta-lactoglobulin by analytical ultracentrifugation and membrane osmometry experiments

Author

Uttinger, M. J., primary, Hundschell, C. S., additional, Lautenbach, V., additional, Pusara, S., additional, Bäther, S., additional, Heyn, T. R., additional, Keppler, J. K., additional, Wenzel, W., additional, Walter, J., additional, Kozlowska, M., additional, Wagemans, A. M., additional, and Peukert, W., additional

Published
2022
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10. UTILIZING LANDSAT AND SENTINEL-2 TO REMOTELY MONITOR AND EVALUATE THE PERFORMANCE OF WINTER COVER CROPS THROUGHOUT MARYLAND

Author

Peredo, J., primary, Wayman, C., additional, Whong, B., additional, Thieme, A., additional, Kline, L. R., additional, Yadav, S., additional, Eder, B., additional, Lenske, V., additional, Portillo, D., additional, McCartney, S., additional, Fitz, J., additional, Oddo, P., additional, Keppler, J., additional, Hively, D., additional, Bolten, J., additional, McCarty, G., additional, and Lyon, A., additional

Published
2020
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12. Resonators for a 2 pole filter fabricated from YBCO coated LaAlO3 cylinders

Author

Kittel, H., Klauda, M., Neumann, C., Dutzi, J., Li, Y.R., Smithey, R., Brecht, E., Schneider, R., Geerk, J., Keppler, J., and Klinger, K.

Subjects
Resonators -- Research, Electric filters, Bandpass -- Design and construction, Business, Electronics, Electronics and electrical industries
Abstract

Dielectric resonators for a two pole filter were developed and tested. They consist of LaAlO3 single crystalline cylinders covered on the cylindrical surface by 4 micrometer gold films and on the end faces by 350 nm YBa2cu3O7-delta thin films. The two-pole bandpass filters fabricated from the resonators have an insertion loss of -0.26 dB at their center frequencies of 6.3 GHz at 77 K.

Published
1997

15. Nutritional intervention by a novel slow-release niacin formulation beneficially alters the gut microbiome and promotes systemic metabolic effects in humans

Author

Fangmann, D, additional, Theismann, EM, additional, Türk, K, additional, Schulte, DM, additional, Relling, I, additional, Hartmann, K, additional, Keppler, J, additional, Knipp, J, additional, Rehmann, A, additional, Freitag-Wolf, S, additional, Wätzig, G, additional, Seegert, D, additional, Rosenstiel, P, additional, Schwarz, K, additional, Schreiber, S, additional, and Laudes, M, additional

Published
2017
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16. Sept propositions pour améliorer le fonctionnement de l'espace électrique européen

Author

Finon, Dominique, Keppler, J., Geoffron, G., centre international de recherche sur l'environnement et le développement (CIRED), and Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École des hautes études en sciences sociales (EHESS)-AgroParisTech-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)

Subjects
[SHS.ECO]Humanities and Social Sciences/Economics and Finance, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2013

22. Uncle Sam's Great Moral and Historical Show

Author

Keppler, J. and Keppler, J.

Abstract

Colored political cartoon featuring Uncle Sam and a collection of corrupt politicians. Under the title, in quotes: "Uncle Sam to the Star Route twins:--"My show will never be complete without you two!"

Published
2009

24. The Spin Structure of the Proton in a Non-relativistic Quark Model

Author

Keppler J and Hofmann Hm

Subjects
Quark, Physics, Particle physics, Nuclear Theory, Proton, Quark model, Hadron, High Energy Physics::Phenomenology, FOS: Physical sciences, Elementary particle, Baryon, Nuclear Theory (nucl-th), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Proton spin crisis, Nucleon, Nuclear Experiment
Abstract

The spin structure of the proton is investigated in the framework of an extended quark potential model which in addition to the conventional $3q$--structure also takes into account $(3q)(q\bar q)$--admixtures in the proton wave function. For reasons of parity such admixtures contain an odd orbital angular momentum thus allowing the proton spin to be shared among quark spins and orbital angular momenta. We show that only certain admixtures are suited for a significant reduction of the quark spin content of the proton as suggested by the EMC--result. Within a Hamiltonian model quark spin contributions to the proton spin down to $0.5$ can be reproduced easily., Comment: email: keppler@faupt31.physik.uni-erlangen.de, 9 pages REVTEX, 1 figure added as PostScript-file which should be stripped off before texing

Published
1994
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27. Water quality and conservation practice effects in the Choptank River watershed

Author

McCarty, G.W., primary, McConnell, L.L., additional, Hapeman, C.J., additional, Sadeghi, A., additional, Graff, C., additional, Hively, W.D., additional, Lang, M.W., additional, Fisher, T.R., additional, Jordan, T., additional, Rice, C.P., additional, Codling, E.E., additional, Whitall, D., additional, Lynn, A., additional, Keppler, J., additional, and Fogel, M.L., additional

Published
2008
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38. Why the climate needs nuclear energy.

Author

Keppler, J. H. and Paillère, H.

Subjects
*NUCLEAR energy & the environment, *CLIMATE change mitigation, *CARBON dioxide mitigation
Abstract

The article discusses the role and adaptation of nuclear energy to climate change mitigation based on the brochure "Nuclear Energy: Combating Climate Change," by the National Electrification Administration (NEA), and offers information on carbon emission reduction and global electricity production.

Published
2015

39. Nuclear new build: Financing and project management.

Author

Keppler, J. H. and Cometto, M.

Subjects
*NUCLEAR power plant design & construction, *CONSTRUCTION project management, *NUCLEAR industry forecasting, *NUCLEAR reactor design & construction, *SUPPLY chain management
Abstract

The article presents an analysis of nuclear new build projects based on three perspectives; the management of long-term electricity price risk, the investment phase, and project management and structure of supply chain. Topics include the state of technical, geographical and structural transition of new build, long-term stabilisation of electricity prices required by capital-intensive projects, and key steps in promoting competition and public confidence in construction of nuclear reactors.

Published
2015

43. System effects of nuclear energy and renewables in low-carbon electricity systems.

Author

Keppler, J. H., Cometto, M., and Cameron, R.

Subjects
*NUCLEAR energy, *RENEWABLE energy sources, *ELECTRICITY, *ELECTRIC power production
Abstract

The article discusses the system effects of nuclear energy and renewables on the structure, financing and operational mode of low-carbon electricity systems. It offers a definition of system effects, its measurement, improved regulatory frameworks for internalising system effects and policy recommendations such as ensuring the transparency of power generation costs at the system level. Tables are presented including grid-level system costs in selected countries like Germany, France and the U.S.

Published
2012

45. The economic costs of the nuclear phase-out in Germany.

Author

Keppler, J. H.

Subjects
*FUKUSHIMA Nuclear Accident, Fukushima, Japan, 2011, *NUCLEAR reactors, *NUCLEAR accidents, *POLITICAL science, *NUCLEAR power plants
Abstract

The article examines the economic costs of the temporary closing of the operation of energy-producing nuclear reactors in Japan following the March 2011 Fukushima Daiichi nuclear power plant accident in Japan. The direct costs of the shutdown involved the costs for constructing and operating replacement capacity on the supply side, increased electricity imports, and higher electricity prices. An important element in determining the cost of the decision of the German government is cited.

Published
2012

47. Carbon pricing and the competitiveness of nuclear power.

Author

Keppler, J. H. and Marcantonini, C.

Subjects
*CARBON offsetting, *NUCLEAR energy, *CARBON dioxide, *EMISSIONS trading, *ELECTRIC industries, *ENVIRONMENTAL impact charges
Abstract

The article highlights a study conducted by the Nuclear Energy Agency (NEA) entitled "Carbon Pricing, Power Markets and the Competitiveness of Nuclear Energy" which examines the competitiveness of nuclear power against coal and gas-fired power generation in liberalised electricity markets with either carbon trading or carbon taxes. It applies daily price data for electricity, gas, coal, and carbon from 2005 to 2010. It provides a robust framework for evaluating cost and investment issues.

Published
2011

48. Security of energy supply and the contribution of nuclear energy.

Author

Cameron, R. and Keppler, J. H.

Subjects
*NUCLEAR energy, *ENERGY security, *OVERHEAD costs, *GREENHOUSE gas mitigation
Abstract

The article discusses a study by the Nuclear Energy Agency on the contribution and security of nuclear energy supply. According to the study, nuclear energy holds advantages that other fuels have which enables it to contribute to both external and internal dimensions of energy supply security. However, due to its fixed costs, nuclear energy is increasingly being dispassionately viewed as solution to questions on security of supply and reductions in greenhouse gas emissions.

Published
2010

50. How competitive is nuclear energy?

Author

Keppler, J. H.

Subjects
*ELECTRIC power production, *NUCLEAR energy, *ECONOMIC competition, *ELECTRIC rates, *MARKET volatility, *ECONOMICS
Abstract

The article discusses the International Energy Agency/Nuclear Energy Agency (IEA/NEA) study on "Projected Costs of Generating Electricity: 2010 Edition" which indicated the competitiveness of nuclear energy in Organization for Economic Cooperation and Development (OECD) member countries and four non-OECD countries. Factors influencing the competitiveness of nuclear energy include interest rates, carbon and fuel prices, and the volatility of electricity prices. Recommendations to bolster the long-term competitiveness of nuclear energy are discussed.

Published
2010

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