cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Weakened magnetic braking as the origin of anomalously rapid rotation in old field stars
Creators: name: van Saders, Jennifer L.
name: Ceillier, Tugdual
name: Metcalfe, Travis S.
name: Aguirre, Victor Silva
name: Pinsonneault, Marc H.
name: García, Rafael A.
name: Mathur, Savita
name: Davies, Guy R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: A knowledge of stellar ages is crucial for our understanding of many astrophysical phenomena, and yet ages can be difficult to determine. As they become older, stars lose mass and angular momentum, resulting in an observed slowdown in surface rotation. The technique of 'gyrochronology' uses the rotation period of a star to calculate its age. However, stars of known age must be used for calibration, and, until recently, the approach was untested for old stars (older than 1 gigayear, Gyr). Rotation periods are now known for stars in an open cluster of intermediate age (NGC 6819; 2.5 Gyr old), and for old field stars whose ages have been determined with asteroseismology. The data for the cluster agree with previous period-age relations, but these relations fail to describe the asteroseismic sample. Here we report stellar evolutionary modelling, and confirm the presence of unexpectedly rapid rotation in stars that are more evolved than the Sun. We demonstrate that models that incorporate dramatically weakened magnetic braking for old stars can---unlike existing models---reproduce both the asteroseismic and the cluster data. Our findings might suggest a fundamental change in the nature of ageing stellar dynamos, with the Sun being close to the critical transition to much weaker magnetized winds. This weakened braking limits the diagnostic power of gyrochronology for those stars that are more than halfway through their main-sequence lifetimes.
description: 25 pages, 3 figures in main paper, 6 extended data figures, 1 table. Published in Nature, January 2016. Please see https://youtu.be/O6HzYgP5uyc for a video description of the result
Rotatable Sputtering Targets for High Rate Deposition of CIGS Thin Films
Creators: name: Schlott, M.
name: Heindel, J.
name: Kastner, A.
name: Pavel, H.
name: Simons, C.
name: Stahr, C.C.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
CIS and Related Ternary and Quaternary Thin Film Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2412-2415
description: Due to its potential for high efficiency PV cells CIGS technology is becoming increasingly important. We report about the development of special, fine grain rotatable target materials for this application and will show data for In, CuGa, and CuInGa tubes on sputtering rates and possible power density obtained in our in-house sputter application laboratory. In addition we will discuss target surface temperatures and the impact of the target microstructure on the sputtering performance. It turns out that fine grains and a homogenous grain structure is key for stable sputtering of Indium and also a prerequisite for a homogenous thin film composition in the case of CuInGa.
On the variation of maximal operators of convolution type II
Creators: name: Carneiro, Emanuel
name: Finder, Renan
name: Sousa, Mateus
Publisher: name: arXiv
Year: 2015
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: In this paper we establish that several maximal operators of convolution type, associated to elliptic and parabolic equations, are variation-diminishing. Our study considers maximal operators on the Euclidean space $\mathbb{R}^d$, on the torus $\mathbb{T}^d$ and on the sphere $\mathbb{S}^d$. The crucial regularity property that these maximal functions share is that they are subharmonic in the corresponding detachment sets.
description: 23 pages
Power Quality Improvement of Electrical Sub-Networks With Multifunctional PV-Inverters for Industrial Customers
Creators: name: Geibel, D.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Components for PV Systems
Engineering and System Integration

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 3096-3102
description: This paper introduces a Multifunctional PV-Inverter and its application for Power Quality improvement in electrical sub-networks. Measurement results point out the potential of this Multifunctional PVInverter concerning protection of sensitive loads against voltage variations, voltage dips and harmonics beside the conventional injection of PV-energy.
Large Area Solar Cells with Screen Printed Front Side Metallization and Dielectric Rear Side Passivation
Creators: name: Pavlovic, R.
name: Dastgheib-Shirazi, A.
name: Book, F.
name: Raabe, B.
name: Hahn, G.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Materials and Cells

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 2185-2189
description: In this work we investigated local rear contact structures and compared these to the full area Al-BSF
structure. Two processes for local contacts are presented: The laser fired contact (LFC) process and a screen printing
process to create a local back surface field (SP-LBSF) structure. The rear side passivation is provided by a firing
stable SiO2/SiNx-stack, using a thin dry thermal SiO2 and a PECVD SiNx. We analyzed several process schemes to
implement the local rear side structure with a screen printed front side metallization. As a flat rear side is very
important for a successful implementation of a solar cell process with dielectric layer passivation, we focused on
these processes. Monocrystalline Cz-Si solar cells (cell size 125x125 mm²) with an LFC structure and up to 17.6%
efficiency were processed. The fabricated LFC cells show an increased reflectivity at long wavelengths due to the
evaporated aluminum on the rear side. Furthermore, the internal quantum efficiency of the LFC and the SP-LBSF
solar cells in the long wavelength range is significantly higher than for solar cells with aluminum back surface field.
Semiclassical Sobolev constants for the electro-magnetic Robin Laplacian
Creators: name: Fournais, Soeren
name: Treust, Loïc Le
name: Raymond, Nicolas
name: Van Schaftingen, Jean
Publisher: name: arXiv
Year: 2016
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: This paper is devoted to the asymptotic analysis of the optimal Sobolev constants in the semiclassical limit and in any dimension. We combine semiclassical arguments and concentration-compactness estimates to tackle the case when an electromagnetic field is added as well as a smooth boundary carrying a Robin condition. As a byproduct of the semiclassical strategy, we also get exponentially weighted localization estimates of the minimizers.
Sustainable Renewable Energy Projects for Intelligent Rural Electrification in Laos, Cambodia and Vietnam
Creators: name: Ortiz, B.
name: Vetter, M.
name: Bourg, C.
name: Crehay, R.
Publisher: name: WIP-Munich
Year: 2010
Subjects: PV Taking Off: Large-scale Deployment
Programmes, Policies and Economics; National and International Initiatives Globally

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 5409-5416
description: The project “Renewable Energy Sustainable Programs for Intelligent Rural Electrification” RESIREA has been
looking for the creation of conditions that make possible the establishment of Renewable Energy Technologies
(RET) markets in targeted provinces of Lao PDR, Cambodia and Vietnam. As a main result of the project, in three
different selected provinces (one in each country) have been proposed villages as ready to implement. The ready to
implement villages are specific RET projects resulted from applying developed methodologies. One methodology is
a deeply well structured cross-analysis of technical and economic parameters and the results have been integrated in
a Geographical Information System GIS. Based on the least-cost methodology, off-grid biomass and photovoltaic PV
power supply systems have been designed and assed for the proposed villages. In the case of PV-Hybrid Mini-Grid
system designs, a detailed study has been carried out by means of simulations tools and exhaustive investigations of
field data. The PV-Hybrid Mini-Grid system design looks to contribute to an easy scale-up concept for off-grid
power supply systems, especially when rural communities are too diverse and make high investments to risky.
Further expected benefits besides the supply of electricity services are the improvement of the living and health
conditions of the populations, as well as the stimulation of local markets for RET and economic activities.
Practical and Rich User Digitization
Creators: name: Ahuja, Karan
Publisher: name: Carnegie Mellon University
Year: 2023
Subjects: Mobile Technologies
Ubiquitous Computing
Computer Vision

description: A long-standing vision in computer science has been to evolve computing devices into proactive assistants that enhance our productivity, health and wellness, and many other facets of our lives. User digitization is crucial in achieving this vision as it allows computers to intimately understand their users, capturing activity, pose, routine, and behavior. Today’s consumer devices – like smartphones and smartwatches – provide a glimpse of this potential, offering coarse digital representations of users with metrics such as step count, heart rate, and a handful of human activities like running and biking. Even these very low-dimensional representations are already bringing value to millions of people’s lives, but there is significant potential for improvement. On the other end, professional, high-fidelity comprehensive user digitization systems exist. For example, motion capture suits and multi-camera rigs that digitize our full body and appearance, and scanning machines such as MRI capture our detailed anatomy. However, these carry significant user practicality burdens, such as financial, privacy, ergonomic, aesthetic, and instrumentation considerations, that preclude consumer use. In general, the higher the fidelity of capture, the lower the user’s practicality. Most conventional approaches strike a balance between user practicality and digitization fidelity. My research aims to break this trend, developing sensing systems that increase user digitization fidelity to create new and powerful computing experiences while retaining or even improving user practicality and accessibility, allowing such technologies to have a societal impact. Armed with such knowledge, our future devices could offer longitudinal health tracking, more productive work environments, full-body avatars in extended reality, and embodied telepresence experiences, to name just a few domains.
Novel Materials and Superstrates for High-Efficiency Micromorph Solar Cells
Creators: name: Ballif, C.
name: Barraud, L.
name: Battaglia, C.
name: Benkhaira, M.
name: Billet, A.
name: Remi, R.
name: Boccard, M.
name: Bugnon, G.
name: Charrière, M.
name: Cuony, P.
name: Despeisse, M.
name: Ding, L.
name: Escarré, J.P.
name: Haug, F.-J.
name: Hänni, S.
name: Löfgren, L.
name: Sculati-Meillaud, F.
name: Nicolay, S.
name: Pahud, C.
name: Parascandolo, G.
name: Perruche, B.
name: De Wolf, S.
name: Söderström, K.
name: Stuckelberger, M.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2384-2391
description: We report on the latest research developments of micromorph (amorphous/microcrystalline) tandem
silicon solar cells in our laboratory. We show that an improved cell design based on the use of silicon oxide doped
layers permits high efficiencies on substrates that are usually considered as inappropriate for microcrystalline silicon
(μc-Si:H) growth. Furthermore, advanced superstrates were recently developed based on, e.g. zinc oxide (ZnO) bilayers,
ZnO multi-scales textures, ZnO nanomolding and ultraviolet nanoimprint lithography, leading to promising
results. While efficiencies of 12.7% initial and 11.3% stable were achieved with a bottom cell only 1.1 m thick on a
rough front ZnO electrode, a high 12% initial efficiency was also reached on a nanoimprinted superstrate. High
initial efficiency single junction microcrystalline devices at 10.9% and micromorph at 14.1% with textured AR
coating are obtained using some of the approaches described in the paper, as well as over 10% stabilized n-i-p cells.
Our lab also placed emphasis on increasing the deposition rate of c-Si:H. So far, conversion efficiencies up to 8.6%
have been achieved with single junction 1.1 μm thick μc-Si:H solar cells deposited at 1.2 nm/s and 12.1% for a
micromorph cell with a 1 m thick bottom cell, for which the absorber layer was grown at 1 nm/s.
An Overview of Patent Application Data in the Field of Photovoltaics
Creators: name: Boneschanscher, M.P.
name: Visentin, A.
name: Boero, M.
name: Fratiloiu, S.
name: Königstein, C.
Publisher: name: WIP-Munich
Year: 2010
Subjects: PV Taking Off: Large-scale Deployment
Programmes, Policies and Economics; National and International Initiatives Globally

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 5328-5331
description: With an annual production of photovoltaic (PV) modules almost exceeding 8 GW of power and
annual increases of well above 30%, PV industries are becoming major players in world economics. At the
same time, patent strategies are becoming increasingly important for the PV industry. The present study is
aimed at providing an overview of patent activities in the PV field covering the past 30 years. In this study, the
number of patent applications published during this time period, per year and for the whole period are analysed.
Patent filing figures are shown for the different types of solar cells including organic solar cells, and dye
sensitized solar cells. Further data are presented showing the origin of patent applications for solar cells as well
as for different decades.
Modelling the circumstellar medium in RS Ophiuchi and its link to Type Ia supernovae
Creators: name: Booth, Richard A.
name: Mohamed, Shazrene
name: Podsiadlowski, Philipp
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Recent interpretations of narrow, variable absorption lines detected in some Type Ia supernovae suggest that their progenitors are surrounded by dense, circumstellar material. Similar variations detected in the symbiotic recurrent nova system RS Oph, which undergoes thermonuclear outbursts every ~20 years, making it an ideal candidate to investigate the origin of these lines. To this end, we present simulations of multiple mass transfer-nova cycles in RS Oph. We find that the quiescent mass transfer produces a dense, equatorial outflow, i.e., concentrated towards the binary orbital plane, and an accretion disc forms around the white dwarf. The interaction of a spherical nova outburst with these aspherical circumstellar structures produces a bipolar outflow, similar to that seen in HST imaging of the 2006 outburst. In order to produce an ionization structure that is consistent with observations, a mass-loss rate of $5 \times 10^{-7}\,\mathrm{M}_{\odot}\,\mathrm{yr}^{-1}$ from the red giant is required. The simulations also produce a polar accretion flow, which may explain the broad wings of the quiescent H α line and hard X-rays. By comparing simulated absorption line profiles to observations of the 2006 outburst, we are able to determine which components arise in the wind and which are due to the novae. We explore the possible behaviour of absorption line profiles as they may appear should a supernova occur in a system like RS Oph. Our models show similarities to supernovae like SN 2006X, but require a high mass-loss rate, $\dot{M} \sim 10^{-6}$ to $10^{-5}\,\mathrm{M_\odot}\,\mathrm{yr}^{-1}$, to explain the variability in SN 2006X.
description: 15 pages, 9 figures. MNRAS accepted
The topological structures in strongly coupled QGP with chiral fermions on the lattice
Creators: name: Sharma, Sayantan
name: Dick, Viktor
name: Karsch, Frithjof
name: Laermann, Edwin
name: Mukherjee, Swagato
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The nature of chiral phase transition for two flavor QCD is an interesting but unresolved problem. One of the most intriguing issues is whether or not the anomalous U(1) symmetry in the flavor sector is effectively restored along with the chiral symmetry. This may determine the universality class of the chiral phase transition. Since the physics near the chiral phase transition is essentially non-perturbative, we employ first principles lattice techniques to address this issue. We use overlap fermions, which have exact chiral symmetry on the lattice, to probe the anomalous U(1) symmetry violation of 2+1 flavor dynamical QCD configurations with domain wall fermions. The latter also optimally preserves chiral and flavor symmetries on the lattice, since it is known that the remnant chiral symmetry of the light quarks influences the scaling of the chiral condensate in the crossover transition region. We observe that the anomalous U(1) is not effectively restored in the chiral crossover region. We perform a systematic study of the finite size and cut-off effects since the signals of U(1) violation are sensitive to it. We also provide a glimpse of the microscopic topological structures of the QCD medium that are responsible for the strongly interacting nature of the quark gluon plasma phase. We study the effect of these microscopic constituents through our first calculations for the topological susceptibility of QCD at finite temperature, which could be a crucial input for the equation of state for anomalous hydrodynamics.
description: 4 Pages, 3 Figures, Proceedings of Quark Matter 2015, Kobe, Japan, version accepted for publication in Nucl. Phys. A
Forecasting Photovoltaic Energy Using a Fourier Series Based Method
Creators: name: Bien, T.
name: Musikowski, H.-D.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Components for PV Systems
Engineering and System Integration

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 3088-3091
description: In this paper a new method of forecasting photovoltaic (PV) energy production is discussed. The significance of PV power production is growing rapidly. This growth could be further accelerated through an efficient method of forecasting such an unpredictable and fluctuating phenomenon like solar irradiance based PV output power. An efficient method of forecasting could limit problems, which mainly occur because of the non-controllable power of Distributed Generation (DG). The forecast is also necessary for efficient management of electricity grids and for investment planning with regard to PV systems. The traditional forecasts of photovoltaic energy are based on the time series of irradiance energy, which are used to calculate the electrical energy of PV systems. In this paper a method of forecasting the energy of PV systems will be shown, which is based on the time series of energy produced by a solar generator. The energy of a PV generator is represented by a time series of daily output energy of the PV generator for three years, which is grouped into 7, 10 and 15 day sums of AC PV energy. The database of the time series was created at the Institute of Electric Power Systems at Otto-von-Guericke University Magdeburg. The forecasts discussed in this paper are made by fitting a time series with a least square fitting method using a Fourier series as a model function. The Fourier series based method of forecasting the photovoltaic energy seems to be very reliable and robust. In this paper several ranks of harmonics of Fourier series were investigated and compared, in order to decide which rank of harmonics could be especially useful for forecasting PV energy.
Global Overview on Grid-Parity Event Dynamics
Creators: name: Breyer, C.
name: Gerlach, A.
Publisher: name: WIP-Munich
Year: 2010
Subjects: PV Taking Off: Large-scale Deployment
Markets for Large-scale PV

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 5283-5304
description: Grid-parity is a very important milestone for further photovoltaic (PV) diffusion. A grid-parity model is presented,
which is based on levelized cost of electricity (LCOE) coupled with the experience curve approach. Relevant
assumptions for the model are given and its key driving forces are discussed in detail. Results of the analysis are
shown for more than 150 countries and a total of 305 market segments all over the world. High PV industry growth
rates enable a fast reduction of LCOE. Depletion of fossil fuel resources and climate change mitigation forces
societies to internalize these effects and pave the way for sustainable energy technologies. First grid-parity events
occur right now. The 2010s are characterized by ongoing grid-parity events throughout the most regions in the world,
reaching an addressable market of about 75% up to 90% of total global electricity market. In consequence, new
political frameworks for maximizing social benefits will be required. In parallel, PV industry tackle its next
milestone, fuel-parity. In conclusion, PV is on the pathway to become a highly competitive energy technology.
Training and Certification of PV Installers in Europe: The PVTRIN Project
Creators: name: Tsoutsos, T.
name: Tournaki, S.
name: Gkouskos, Z.
name: Despotou, E.
name: Masson, G.
Publisher: name: WIP-Munich
Year: 2010
Subjects: PV Taking Off: Large-scale Deployment
Awareness, Communication, Education and Training

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 5314-5317
description: The high photovoltaic market growth rates, which are further favored by the EU supporting policies
and the favorable national regulatory frameworks within the Member State countries, may turn to a threat for the PV
industry due to the lack of adequately skilled workforce for the PV installation and maintenance. This may result in
poorly installed systems with negative impact on the PV industry’s credibility and development. Furthermore, the
interested parties (developers, designers, potential users) will eventually seek for acknowledged standards, skills
certification and quality assurance throughout the development of a PV/BIPV application (design, installation, and
maintenance). The PVTRIN, an Intelligent Energy Europe (IEE) project, addresses to these issues, by developing a
training and certification scheme for the technicians/electricians/engineers that activate in the installation and
maintenance of small scale PV systems. The training and certification scheme will incorporate the criteria set by the
2009/28/EC Directive, providing a supporting instrument for EU Member States to meet their obligations for
acknowledged certifications for RES installers till 31/12/2012. Creating a qualified PV installers workforce, the
increased confidence of potential PV owners will lead to market growth.
The Way to 11% Stabilized Module Efficiency Based on 1.4m2 Micromorph® Tandem
Creators: name: Kluth, O.
name: Kalas, J.
name: Fecioru-Morariu, M.
name: Losio, P.A.
name: Hötzel, J.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2354-2357
description: This paper reports about the progress on the way to achieve 11 % stabilized module efficiency based
on industrial Micromorph® tandem processes. Innovative approaches of multilayer LPCVD ZnO front contacts are
presented which allow to tailor the layer properties more independently and to tune the morphology in a desirable
way. The development of a-Si:H absorber layers with high current density and reduced microstructure factor has lead
to extremely low average relative degradation of 17.2 % after 1700 h light soaking and a new record stabilized power
for 1.4 m2 a-Si:H single junction modules of 115.2Wp and 8.7 % stabilized active area efficiency. Combined with an
improved bottom cell PECVD hardware and process, an initial record module power of 175 Wp and 13.1 % active
area efficiency was achieved for a 1.4 m2 Micromorph® tandem module. Based on the measured average degradation
of 10x10 cm2 mini-modules this corresponds to 154 Wp stabilized module power and 10.8 % stabilized total area
efficiency.
Laser Ablation of Etch Resists for Structuring and Lift-Off Processes
Creators: name: Knorz, A.
name: Grohe, A.
name: Preu, R.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Materials and Cells

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 2164-2167
description: Structuring of dielectric and metal layers as well as silicon itself are key processes in the production of silicon
solar cells. In this paper we suggest selective structuring of etch resist and organic lacquers by laser ablation as a general
structuring approach. This approach is a simple and fast way of creating small structures in an etch resists or a precursor for
lift- off processes. Two possible applications for laser structured organic lacquers will be presented in this paper. One
application includes the structured etch resist technology for the electrical isolation of an aluminum layer acting as a rear side
metallization for back contacted cells, the other is based on a lift-off application leading to a process sequence for a front
side metallization. Since etch resist absorbs light at wavelengths in the infrared regime (2 - 10 μm) which are not absorbed in
silicon the chance of damaging the wafer by choosing an appropriate laser system can be reduced. To this point high
efficiency solar cells with Ps-FF of up to 83.1 % and VOC of 661 mV were fabricated.
Investigation of the Carrier Lifetime Near the p- to n-Type Transition Point in UMG-Silicon
Creators: name: Kaden, T.
name: Zierer, R.
name: Kreßner-Kiel, D.
name: Möller, H.J.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Wafer-Based Silicon Solar Cells and Materials Technology
Silicon Feedstock, Crystallisation and Wafering

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 1583-1585
description: Upgraded metallurgical-grade silicon (umg-Si) contains high concentrations of metallic impurities and
dopants. Due to the different segregation behaviour of the dopants there is a transition point of conductivity from pto
n-type in the direction of crystallisation. We present an easy and fast method to visualise this transition point using
a surface photovoltage setup. Furthermore, we investigate the minority carrier diffusion lengths and lifetimes in the
transition region. An attempt is undertaken to characterise the recombination active defects using injection dependent
SPV measurements.
Tribological Approach for Understanding the Multi Wire Sawing of Silicon Wafers
Creators: name: Skomedal, G.
name: Espallargas, N.
name: Øvrelid, E.J.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Wafer-Based Silicon Solar Cells and Materials Technology
Silicon Feedstock, Crystallisation and Wafering

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 1604-1609
description: Almost 100% of today’s wafering of crystalline silicon for solar cells are done with multi wire slurry
sawing. To be able to produce thinner and cheaper wafers without reducing the surface quality, an in-depth
knowledge of the basic mechanisms of material removal is necessary. Previous research works have been focused on
the study of the interaction of the micro indentations of the silicon carbide (SiC) particles with the silicon crystal
causing chip-off by brittle fracture. The correlation between a typical Vickers-indenter used in hardness
measurements and the indentation mechanism observed in the sawing process has been investigated by several
authors and the basics of the cutting mechanisms have been established by proposing models. However, these basic
knowledge and models are not enough for understanding and predicting the performance of the industrial process,
thus the optimization of the process requires of more realistic laboratory testing and models. In this article, the three
body interaction between steel wire, SiC particles and the silicon crystal in a wire saw process has been studied using
a pin-on-plate test. Experiments were conducted with varying SiC grit sizes and normal forces between a steel
counterpart and a polysilicon substrate. The material removal rate showed a linear relation with the normal force
applied, just as found in a wire saw. Also, at low loads, the surface topography of the wear track was similar to the ascut
wafers. Size and shape effects of the SiC grit showed good correlation with what found in a wire saw.
Scattering solutions of Bethe-Salpeter equation in Minkowski and Euclidean spaces
Creators: name: Carbonell, J.
name: Karmanov, V. A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We shortly review different methods to obtain the scattering solutions of the Bethe-Salpeter equation in Minkowski space. We emphasize the possibility to obtain the zero energy observables in terms of the Euclidean scattering amplitude.
description: 7 pages, 2 figures, contribution to the conference Light-Cone 2015, Frascati, Italy, 21-25 September, 2015. Submitted in Few-Body Systems
Efficiency Improvement for a-Si/µc-Si Tandem Junctions, via Multi-Terminal Structures
Creators: name: Kasouit, S.
name: Hudanski, L.
name: Francke, L.
name: Damon-Lacoste, J.
name: Besnier, J.-F.
name: Roschek, T.
name: Ahmed, K.
name: Zhao, L.
name: Sheng, S.
name: Cassagne, V.
name: Vermeersch, M.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2371-2374
description: This paper presents the results of amorphous silicon / microcrystalline silicon tandem junction using a
four terminal configuration where the sub-cells are coupled optically but not electrically, allowing the maximum
power point of each junction to be defined independently. On exploratory, prototype structures, initial efficiencies of
11.6 % were measured under AM1.5 illumination, yielding significant absolute gains compared to near optimal
conventional tandem modules, net gains being also observed after light soaking. Moreover, measurements under low
irradiance conditions have shown an additional relative gain in excess of 5% below 500W/m2, which has also been
confirmed under real outdoors conditions. These encouraging results are opening up an additional path towards high
efficiency thin film silicon solar devices.
Dynamic structure factor of liquid 4He across the normal-superfluid transition
Creators: name: Ferre, G.
name: Boronat, J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We have carried out a microscopic study of the dynamic structure factor of liquid $^4$He across the normal-superfluid transition temperature using the path integral Monte Carlo method. The ill-posed problem of the inverse Laplace transform, from the imaginary-time intermediate scattering function to the dynamic response, is tackled by stochastic optimization. Our results show a quasi-particle peak and a small and broad multiphonon contribution. In spite of the lack of strength in the collective peaks, we clearly identify the rapid dropping of the roton peak amplitude when crossing the transition temperature $T_λ$. Other properties such as the static structure factor, static response, and one-phonon contribution to the response are also calculated at different temperatures. The changes of the phonon-roton spectrum with the temperature are also studied. An overall agreement with available experimental data is achieved.
description: 10 pages
Innovative Series Connection Concept for Thin-Film Solar Modules
Creators: name: Haas, S.
name: Bauer, A.
name: Lambertz, A.
name: Rau, U.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2375-2378
description: The paper introduces a new type of series connection that can considerably increase the active area and
thus the efficiency of a thin film module by a superior arrangement of the patterning grooves. We describe the
functionality of the innovative series connection and demonstrate the applicability of the new concept for a laser
patterned thin film silicon solar module. For this module the new series connection leads to an relative efficiency increase
of approximately 3%.
Optimal Solar Field Design of Stationary and Single Axis Tracking Photovoltaic Collectors
Creators: name: Appelbaum, J.
name: Weinstock, D.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Components for PV Systems
Engineering and System Integration

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 3062-3067
description: The design of stationary and single axis tracking collectors in a field consisting of rows of collectors involves relationships between the field and collector parameters and solar radiation data. Shading and masking of
adjacent rows may affect the collector deployment by decreasing the incident energy on the collector. The use of many rows increases the field incident energy but also increases the shading. Therefore there is an optimal
deployment of the collectors in the field yielding, for example, maximum output energy or other objectives. For photovoltaic collectors, the output energy of the field depends on the collector efficiency; the solar cell operating
temperature; and on the scheme of the electrically interconnected modules. Series interconnection may have a significant effect on the output energy of the solar plant in event of shading. The present article deals with the optimal design of photovoltaic solar fields for stationary and single axis tracking collectors to obtain maximum annual output energy. Two single axis tracking methods were used: north-south horizontal axis east-west tracking, and east-west horizontal axis north-south tracking. The optimal results of the two tracking methods were compared to the results obtained for stationary collectors.
Concept for Large-Scale-Deployment of Grid Connected PV in the Private Sector at the Edge of Grid Parity
Creators: name: Heilscher, G.
name: Gmehlin, M.
name: Conrad, J.
name: Ehm, A.
Publisher: name: WIP-Munich
Year: 2010
Subjects: PV Taking Off: Large-scale Deployment
Markets for Large-scale PV

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 5305-5308
description: Which role PV energy will play in a 100% renewable energy system? To be able to answer the question
we need to know: 1 - Realistic load curves in real time, 2 - Behavior of PV systems in real time, 3 - Todays energy
market economics, 4 - Concepts for the transition to an energy market based on decentralized energy.
The paper analyses load profiles from single households with real time measurement (2 second time resolution) and
150 households with quarter hourly load curves. In detail the effect of direct use of energy is evaluated. A stock
exchange valuation of the different load curves with the EEX prices from 2005 to 2010 establishes the basis for the
development of business modes with today’s and future energy market economics.
Training, Skill and Certification in PV Installations
Creators: name: Moreno, A.
name: Castello, S.
name: Pistochini, P.
name: Bonfiglio, L.
Publisher: name: WIP-Munich
Year: 2010
Subjects: PV Taking Off: Large-scale Deployment
Awareness, Communication, Education and Training

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 5309-5313
description: In Italy the installed PV power has increased from 120 MW at the beginning of 2008 to 800 MW
at the end of 2009. As a consequence in the last two years the net value of PV business in Italy has increased of
an order of magnitude reaching an annual amount of 1300 M€. In this context it is interesting to evaluate the
corresponding training activities for designers and installers especially in Italy, where there is a high amount of
imported components and most people have to be trained in designing and installing.
The Directive 2009/28/EC of the 23rd April 2009 introduces a novelty for installers of PV plants. Before
December 31st 2012, the Member states have to provide the installers a certification or a qualification system,
based on a mutual recognition.
ENEA and Mesos have performed interviews with the installers and installing companies to find out whether
they are in favour of a certification and to what extend the education influenced their work.
DGS Manual for PV-Systems - Now in 4th Edition
Creators: name: Haselhuhn, R.
name: Vanicek, P.
name: Hartmann, U.
Publisher: name: WIP-Munich
Year: 2010
Subjects: PV Taking Off: Large-scale Deployment
Awareness, Communication, Education and Training

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 5325-5327
description: Ten years ago the renewable energy law has been introduced in Germany. This was the starting point of an incredible success
story of PV-Systems in the country. 44 MW grid connected PV-systems have been newly installed in 2000. In the year 2009
this has increased to 3,800 MWp.
Thus DGS decided in 2000 to produce a manual Photovoltaic Systems for craftsmen, engineers, architects and all interested
people which contains all important features for optimal dimensioning, installation, operation and maintenance. Since then
the manual has been sold more than 12,000 times. DGS has published in April 2010 the 4th edition of the PV-manual with
new contents. The 4th edition will be the basis for the translation into English, Italian, Spanish and Turkish language.
Performance Trade-Offs in Multi-Processor Approximate Message Passing
Creators: name: Zhu, Junan
name: Beirami, Ahmad
name: Baron, Dror
Publisher: name: arXiv
Year: 2016
Subjects: subject: Information Theory (cs.IT)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: We consider large-scale linear inverse problems in Bayesian settings. Our general approach follows a recent line of work that applies the approximate message passing (AMP) framework in multi-processor (MP) computational systems by storing and processing a subset of rows of the measurement matrix along with corresponding measurements at each MP node. In each MP-AMP iteration, nodes of the MP system and its fusion center exchange lossily compressed messages pertaining to their estimates of the input. There is a trade-off between the physical costs of the reconstruction process including computation time, communication loads, and the reconstruction quality, and it is impossible to simultaneously minimize all the costs. We pose this minimization as a multi-objective optimization problem (MOP), and study the properties of the best trade-offs (Pareto optimality) in this MOP. We prove that the achievable region of this MOP is convex, and conjecture how the combined cost of computation and communication scales with the desired mean squared error. These properties are verified numerically.
description: 5 pages, 2 figures, to appear at 2016 IEEE International Symposium on Information Theory (ISIT2016)
Light Amplification in Semiconductor-Superconductor Structures
Creators: name: Marjieh, Raja
name: Sabag, Evyatar
name: Hayat, Alex
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study a new effect of Cooper-pair-based two-photon gain in semiconductor-superconductor structures, showing broadband enhancement of ultrafast two-photon amplification. We further show that with the superconducting enhancement, at moderately high seed intensities the two-photon gain contribution approaches that of the one-photon gain. A full quantum-optical model of singly- and fully-stimulated two-photon emission is developed. Our results provide new insights on nonlinear light-matter interaction in the superconducting state, including the possibility of coherent control in two-photon semiconductor-superconductor devices. The theoretically demonstrated effects can have important implications in optoelectronics and in coherent control applications.
Development of Photovoltaics in the EU New Member States - 2009
Creators: name: Pietruszko, S.M.
name: Blazejewska, K.
name: Dimova-Malinovska, D.
name: Vitanov, P.
name: Stylianides, A.
name: Müller, M.
name: Mellikov, E.
name: Palfy, M.
name: Shipkovs, P.
name: Krotkus, A.
name: Mifsud, P.
name: Teodoreanu, D.
name: Voderadska, Z.
name: Nemac, F.
Publisher: name: WIP-Munich
Year: 2010
Subjects: PV Taking Off: Large-scale Deployment
Awareness, Communication, Education and Training

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 5276-5279
description: Development of PV technology in the twelve European Union New Member States (NMS) that joined
the European Union after 2004 is crucial considering the EU target to raise the share of renewable energy sources in a
total energy mix up to 20% by 2020. Data collected through the cooperation of over twelve national institutes and
research centers from NMS, furnished, for the 7th time, the report on the status of PV in the new EU member states.
It shows diversity of PV NMS markets, conditioned by original energy market profile, territory’s irradiation, legal
order, administrative procedures and investment support mechanisms.
Multi-path Model and Sensitivity Analysis for Galvanic Coupled Intra-body Communication through Layered Tissue
Creators: name: Swaminathan, Meenupriya
name: Cabrera, Ferran Simon
name: Pujol, Joan Sebastia
name: Muncuk, Ufuk
name: Schirner, Gunar
name: Chowdhury, Kaushik R.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: Emerging Technologies (cs.ET)
subject: FOS: Computer and information sciences

description: New medical procedures promise continuous patient monitoring and drug delivery through implanted sensors and actuators. When over the air wireless radio frequency (OTA-RF) links are used for intra-body implant communication, the network incurs heavy energy costs owing to absorption within the human tissue. With this motivation, we explore an alternate form of intra-body communication that relies on weak electrical signals, instead of OTA-RF. To demonstrate the feasibility of this new paradigm for enabling communication between sensors and actuators embedded within the tissue, or placed on the surface of the skin, we develop a rigorous analytical model based on galvanic coupling of low energy signals. The main contributions in this paper are: (i) developing a suite of analytical expressions for modeling the resulting communication channel for weak electrical signals in a three dimensional multi-layered tissue structure, (ii) validating and verifying the model through extensive finite element simulations, published measurements in existing literature, and experiments conducted with porcine tissue, (iii) designing the communication framework with safety considerations, and analyzing the influence of different network and hardware parameters such as transmission frequency and electrode placements. Our results reveal a close agreement between theory, simulation, literature and experimental findings, pointing to the suitability of the model for quick and accurate channel characterization and parameter estimation for networked and implanted sensors.
description: This paper has been accepted for publication in IEEE Transaction on Biomedical Circuits and Systems and will appear in March 2016 issue. This is an author copy
Throughput Optimized a-Si/µc-Si Tandem Solar Cells on Sputter-Etched ZnO
Creators: name: Rohde, M.
name: Severin, D.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2366-2370
description: Recently, Applied Materials has demonstrated the ability to manufacture large area a-Si/μc-Si thin film
modules with total area efficiencies of 10% and above. Reducing the production costs is now the key objective for an
economic success of this technology. Decreasing the absorber layer thickness or increasing the deposition rate can
reduce the cost significantly because the PECVD deposition of the silicon layers is one of the main cost contributors.
But this would also reduce the conversion efficiency of amorphous/microcrystalline tandem junction (TJ) cells.
Therefore, optimizing TJ cells for maximal productivity requires a careful balancing of layer thicknesses and
deposition rates. In this paper we studied the impact of deposition rates and absorber layer thicknesses for top and
bottom cells. The reduction of the bottom cell (BC) thickness from 2μm to less than 1μm showed only a small impact
on the stabilized module efficiency while having a big impact on the productivity of a production line. 10.2% stable
mini-module efficiency could be achieved with 900nm BC thickness, reducing the deposition time by 50%.
Strategy for Optimizing the Dynamic Behavior of a Polar Tracking System
Creators: name: Alexandru, C.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Components for PV Systems
Engineering and System Integration

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 3068-3073
description: The paper presents researches on increasing the efficiency of the photovoltaic conversion, by designing and optimizing a polar tracking mechanism for a PV array in string configuration. The main task in optimizing the photovoltaic system is to maximize the energetic gain by increasing the solar input and minimizing
the energy consumption for tracking. In order to accomplish the paper goal, possible solutions for tracking the sun movement are comparatively analyzed: step-by-step tracking, with different number of steps, and continuous orientation, respectively. The evaluation is made having in view the energetic balance of the tracking system (the electric energy produced by the photovoltaic array with tracking versus the energy consumption for realizing the motion law), relative to the fixed array case.