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Search Results: 1 - 10 of 319 matches for " Bjoern Loeptien "
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Business Model for Local Distribution Companies to Promote Renewable Energy  [PDF]
Bjoern Buesing, Ming Yang
Low Carbon Economy (LCE) , 2013, DOI: 10.4236/lce.2013.44A005
Abstract:

Decentralized or distributed small renewable power facilities are usually installed in local communities for households and small business companies. These facilities include solar PV, concentrated solar power, and wind power, etc. In order to promote installations of such facilities, governments in many countries have developed a number of policies and business models. For example, in Germany and Canada, electricity feed-in tariff policy and business model were developed; in the USA, tax rebate policies and relevant business models were promoted. These policies and models have in some but not in large scale promoted decentralized small renewable power in local communities. The key issue is that these policies and business models do not provide sufficient incentives to local distribution companies (LDC), nor to renewable power installers and users. This paper’s research covers the creation of a business and communication model, named as LDC model, to incentivize both renewable power installers/users and LDCs. This LDC model can play a key role in promoting decentralized small-scale generation (DSG) with renewable energy in local communities. The core element of the LDC model is a revenue model which serves as an instrument to finance renewable installations for households and small commercial businesses. A case study is undertaken with real data of a power distribution company in Toronto, Canada. This paper concludes that with appropriate government policy and with the development of customized information systems for accessing households and small business via internet, an LDC will be able to take leadership in investing and installing small renewable power, and consequently enlarge the share of renewable energy supply in its local power distribution network.

EXOTIME: searching for planets around pulsating subdwarf B stars
Sonja Schuh,Roberto Silvotti,Ronny Lutz,Bjoern Loeptien,Elizabeth M. Green,Roy H. Ostensen,Silvio Leccia,Seung-Lee Kim,Gilles Fontaine,Stephane Charpinet,Myriam Francoeur,Suzanna Randall,Cristina Rodriguez-Lopez,Valerie van Grootel,Andrew P. Odell,Margit Paparo,Zsofia Bognar,Peter Papics,Thorsten Nagel,Benjamin Beeck,Markus Hundertmark,Thorsten Stahn,Stefan Dreizler,Frederic V. Hessman,Massimo Dall'Ora,Dario Mancini,Fausto Cortecchia,Serena Benatti,Riccardo Claudi,Rimvydas Janulis
Physics , 2010, DOI: 10.1007/s10509-010-0356-4
Abstract: In 2007, a companion with planetary mass was found around the pulsating subdwarf B star V391 Pegasi with the timing method, indicating that a previously undiscovered population of substellar companions to apparently single subdwarf B stars might exist. Following this serendipitous discovery, the EXOTIME (http://www.na.astro.it/~silvotti/exotime/) monitoring program has been set up to follow the pulsations of a number of selected rapidly pulsating subdwarf B stars on time-scales of several years with two immediate observational goals: 1) determine Pdot of the pulsational periods P 2) search for signatures of substellar companions in O-C residuals due to periodic light travel time variations, which would be tracking the central star's companion-induced wobble around the center of mass. These sets of data should therefore at the same time: on the one hand be useful to provide extra constraints for classical asteroseismological exercises from the Pdot (comparison with "local" evolutionary models), and on the other hand allow to investigate the preceding evolution of a target in terms of possible "binary" evolution by extending the otherwise unsuccessful search for companions to potentially very low masses. While timing pulsations may be an observationally expensive method to search for companions, it samples a different range of orbital parameters, inaccessible through orbital photometric effects or the radial velocity method: the latter favours massive close-in companions, whereas the timing method becomes increasingly more sensitive towards wider separations. In this paper we report on the status of the on-going observations and coherence analysis for two of the currently five targets, revealing very well-behaved pulsational characteristics in HS 0444+0458, while showing HS 0702+6043 to be more complex than previously thought.
Lepton Flavor Violation in the LHT - A Clear Distinction from Supersymmetry
Duling, Bjoern
High Energy Physics - Phenomenology , 2007,
Abstract: The Littlest Higgs Model with T-Parity (LHT) contains new sources of flavor and CP violation both in the quark and lepton sector. These have their origin in interactions of ordinary fermions with mirror fermions mediated by new heavy gauge bosons. Large deviations from the Standard Model (SM) are to be expected in the lepton sector where tiny neutrino masses suppress the SM predictions by many orders of magnitude below the experimentally accessible level. Here we give a brief summary of LFV processes relevant for the foreseeable future and point out that correlations between branching ratios of LFV decays in the LHT exhibit a structure vastly different from their analogues in the MSSM, thus allowing for a transparent distinction between these two models.
Collective Phenomena in the Non-Equilibrium Quark-Gluon Plasma
Schenke, Bjoern
High Energy Physics - Phenomenology , 2008,
Abstract: In this work we study the non-equilibrium dynamics of a quark-gluon plasma, as created in heavy-ion collisions. We investigate how big of a role plasma instabilities can play in the isotropization and equilibration of a quark-gluon plasma. In particular, we determine, among other things, how much collisions between the particles can reduce the growth rate of unstable modes. This is done both in a model calculation using the hard-loop approximation, as well as in a real-time lattice simulation combining both classical Yang-Mills-fields as well as inter-particle collisions. The new extended version of the simulation is also used to investigate jet transport in isotropic media, leading to a cutoff-independent result for the transport coefficient q-hat. The precise determination of such transport coefficients is essential, since they can provide important information about the medium created in heavy-ion collisions. In anisotropic media, the effect of instabilities on jet transport is studied, leading to a possible explanation for the experimental observation that high-energy jets traversing the plasma perpendicular to the beam axis experience much stronger broadening in rapidity than in azimuth. The investigation of collective modes in the hard-loop limit is extended to fermionic modes, which are shown to be all stable. Finally, we study the possibility of using high energy photon production as a tool to experimentally determine the anisotropy of the created system. Knowledge of the degree of local momentum-space anisotropy reached in a heavy-ion collision is essential for the study of instabilities and their role for isotropization and thermalization, because their growth rate depends strongly on the anisotropy
T-S-T dual black hole
Bjoern Andreas
Physics , 1996, DOI: 10.1142/S0217751X9700133X
Abstract: The sequence of intertwined T-S-T duality transformations acting on the 4D static uncharged black hole leads to a new black hole background with horizon and singularity exchanged. It is shown that this space-time is extendible too. In particular we will see that a string moving into a black hole is dual to a string leaving a white hole. That offers the possibility that a test-string does not see the singularity.
Jet evolution in Yang-Mills-Wong simulations
Bjoern Schenke
Physics , 2009, DOI: 10.1016/j.nuclphysa.2009.09.056
Abstract: We present results for collisional energy loss and momentum broadening of high momentum partons in a hot and dense non-Abelian plasma obtained by solving the coupled system of Yang-Mills-Wong equations on a lattice in real time. Including hard elastic collisions among the particles we obtain cutoff independent results for the collisional energy loss dE/dx and the transport coefficient q-hat. The latter is found to receive a sizable contribution from a power-law tail in the transverse momentum distribution of high-momentum partons. We further argue that the effect of instabilities on jet broadening should be accessible by experiment when employing jet cones with elliptical bases or studying correlations within the cone in full jet reconstruction methods.
On the Existence of certain Quantum Algorithms
Bjoern Grohmann
Physics , 2009,
Abstract: We investigate the question if quantum algorithms exist that compute the maximum of a set of conjugated elements of a given number field in quantum polynomial time. We will relate the existence of these algorithms for a certain family of number fields to an open conjecture from elementary number theory.
Search for H->WW->ll at D0
Bjoern Penning
Physics , 2008,
Abstract: A search for the Higgs boson in H -> WW -> ll(l = e, mu) decays in ppbar collisions at a center-of-mass energy of sqrt{s}=1.96 TeV is presented. The data have been collected by the Run II DO detector between April 2002 and June 2008, corresponding to 3 fb^{-1} of integrated luminosity. In order to maximize the sensitivity the multivariate technique of Artificial Neural Networks is used. No excess above the Standard Model background is observed and limits on the production cross section times branching ratio sigma x BR(H -> WW -> ll) for m_H=115 - 200 GeV using a Higgs mass grid of 5 GeV have been set.
Collective Phenomena in the Non-Equilibrium Quark-Gluon Plasma
Bjoern Schenke
Physics , 2008,
Abstract: In this work we study the non-equilibrium dynamics of a quark-gluon plasma, as created in heavy-ion collisions. We investigate how big of a role plasma instabilities can play in the isotropization and equilibration of a quark-gluon plasma. In particular, we determine, among other things, how much collisions between the particles can reduce the growth rate of unstable modes. This is done both in a model calculation using the hard-loop approximation, as well as in a real-time lattice simulation combining both classical Yang-Mills-fields as well as inter-particle collisions. The new extended version of the simulation is also used to investigate jet transport in isotropic media, leading to a cutoff-independent result for the transport coefficient q-hat. The precise determination of such transport coefficients is essential, since they can provide important information about the medium created in heavy-ion collisions. In anisotropic media, the effect of instabilities on jet transport is studied, leading to a possible explanation for the experimental observation that high-energy jets traversing the plasma perpendicular to the beam axis experience much stronger broadening in rapidity than in azimuth. The investigation of collective modes in the hard-loop limit is extended to fermionic modes, which are shown to be all stable. Finally, we study the possibility of using high energy photon production as a tool to experimentally determine the anisotropy of the created system. Knowledge of the degree of local momentum-space anisotropy reached in a heavy-ion collision is essential for the study of instabilities and their role for isotropization and thermalization, because their growth rate depends strongly on the anisotropy
Flow in heavy-ion collisions - Theory Perspective
Bjoern Schenke
Physics , 2011, DOI: 10.1088/0954-3899/38/12/124009
Abstract: I review recent developments in the field of relativistic hydrodynamics and its application to the bulk dynamics in heavy-ion collisions at the Relativistic Heavy- Ion Collider (RHIC) and the Large Hadron Collider (LHC). In particular, I report on progress in going beyond second order relativistic viscous hydrodynamics for conformal fluids, including temperature dependent shear viscosity to entropy density ratios, as well as coupling hydrodynamic calculations to microscopic hadronic rescattering models. I describe event-by-event hydrodynamic simulations and their ability to compute higher harmonic flow coefficients. Combined comparisons of all harmonics to recent experimental data from both RHIC and LHC will potentially allow to determine the desired details of the initial state and the medium properties of the quark-gluon plasma produced in heavy-ion collisions.
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