cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Combining Deep Learning and Physics Models for Efficient and Robust Architectures
Creators: name: De Avila Belbut, Filipe
Publisher: name: Carnegie Mellon University
Year: 2023
Subjects: subject: Artificial Intelligence and Image Processing
subject: FOS: Computer and information sciences

description: Over the last decade, deep learning methods have achieved success in diverse domains, becoming one of the most widely employed approaches in artificial intelligence. These recent successes have also motivated their application in physics domains, such as solving differential equations, or predicting the motion of objects or the behavior of fluids. Deep learning methods have as their strengths their extreme flexibility, allowing complex dynamics to be learned directly from data, and their proven track record working directly on unstructured, high-dimensional domains (such as image and video processing). However, these approaches also face some issues, such as difficulty in generalizing outside the training domain, large data requirements, and costly training. Traditional models of physics, on the other hand, have been developed to be universally valid within their domain of application (i.e., generalizable) and require little to no data for modelling. In this proposal, we present methods for leveraging the strengths of both types of approaches, by combining deep learning and physics models. This allows for the development of deep learning architectures that are more dataefficient and robust to generalization than their standard, “physics-unaware” counterparts. These methods fall under two broad categories: differentiable physics layers and physics-informed learning approaches. In the first group of methods, we embed full physics simulators as layers into deep learning models, fully constraining their outputs to match the underlying dynamics. By having these simulations be fully differentiable, we maintain the ability to train these systems end-to-end. We present the application of such methods to problems in rigid body and fluid dynamics. Physics-informed learning methods provide information about the underlying physics in the form of physics-informed loss terms, which regularize the model’s outputs to be physically consistent. We present a method to improve these approaches in order to learn parameterized systems of differential equations more efficiently. We also analyze theoretically and empirically the usage of sinusoidal neural networks to address known issues, such as spectral bias, in neural networks performing physics-informed learning.
Uniform Reference Structures to Assess the Benefit of Grading in Thin Film Solar Cell Structures
Creators: name: Decock, K.
name: Khelifi, S.
name: Burgelman, M.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Thin Film Solar Cells
CIS and Other (II-VI) Ternary Thin Film Solar Cells

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 3323-3326
description: The Cu(In,Ga)(S,Se)2-material system (CIGSSe) has an adjustable band gap which allows to make
structures with a varying band gap throughout the film thickness. Because the performance of solar cells with a
uniform composition is dependent on the band gap, it is necessary to compare the efficiency of a solar cell having
such a graded band gap absorber with the efficiency of an adequate uniform reference sample. Several references are
compared and a new procedure to assess the efficiency gain of graded band gap solar cells is introduced which
allows a non-arbitrary and objective appraisal.
One Year Round Robin Testing of Irradiation Sensors - Measurement Results and Analyses
Creators: name: Zehner, M.
name: Fritze, P.
name: Schlatterer, M.
name: Glotzbach, T.
name: Schulz, B.
name: Vodermayer, C.
name: Mayer, M.
name: Wotruba, G.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Components for PV Systems
Engineering and System Integration

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 3800-3805
description: The objective of this evaluation is an analysis of different, calibrated and commercially available
irradiance sensors, to give a decision matrix with deficits or advantages for the application of each single sensor.
Basis for this assessment is a Round-Robin-Test (RRT) with two identical experimental setups located at sites in
Germany (Fraunhofer IWES Kassel and University of Applied Sciences Munich). The evaluation started at the end
of the year 2007 with 18 irradiance sensors on each test arrangement and meanwhile provided over one year of
operational experience. The sensor functionality and the measuring data of the sensors in their instantaneous values,
daily, monthly and annual energy sum values are regarded. The measured data base helps to compare sensors of
different and matching technologies under similar field conditions (diurnal variations at different locations and under
specific weather conditions). In awareness of the operational behaviour of PV-systems (different technologies in
certain weather situations), the relation to the operational experience of the irradiance sensors shows interesting
aspects on the quality of system performance statements.
Room temperature chiral magnetic skyrmion in ultrathin magnetic nanostructures
Creators: name: Boulle, Olivier
name: Vogel, Jan
name: Yang, Hongxin
name: Pizzini, Stefania
name: Chaves, Dayane de Souza
name: Locatelli, Andrea
name: Sala, Tevfik Onur Menteş Alessandro
name: Buda-Prejbeanu, Liliana D.
name: Klein, Olivier
name: Belmeguenai, Mohamed
name: Roussigné, Yves
name: Stashkevich, Andrey
name: Chérif, Salim Mourad
name: Aballe, Lucia
name: Foerster, Michael
name: Chshiev, Mairbek
name: Auffret, Stéphane
name: Miron, Ioan Mihai
name: Gaudin, Gilles
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Magnetic skyrmions are chiral spin structures with a whirling configuration. Their topological properties, nanometer size and the fact that they can be moved by small current densities have opened a new paradigm for the manipulation of magnetisation at the nanoscale. To date, chiral skyrmion structures have been experimentally demonstrated only in bulk materials and in epitaxial ultrathin films and under external magnetic field or at low temperature. Here, we report on the observation of stable skyrmions in sputtered ultrathin Pt/Co/MgO nanostructures, at room temperature and zero applied magnetic field. We use high lateral resolution X-ray magnetic circular dichroism microscopy to image their chiral Néel internal structure which we explain as due to the large strength of the Dzyaloshinskii-Moriya interaction as revealed by spin wave spectroscopy measurements. Our results are substantiated by micromagnetic simulations and numerical models, which allow the identification of the physical mechanisms governing the size and stability of the skyrmions.
description: Submitted version. Extended version to appear in Nature Nanotechnology
Analysis of the Maximum Power Point Tracking in the Photovoltaic Grid-Connected Inverters of around 5 kW
Creators: name: Salas, V.
name: Débora, P.J.
name: Olías, E.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Components for PV Systems
Balance of System Components

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 3823-3826
description: The aim of this article is to describe how closely PV grid-connected inverters operate at the actual
maximum power point. To carry this study out six 50 Hz single-phase inverters were selected from European market.
Each one of them was put into an outdoor grid-connected system installed in Leganés (Madrid) Spain (by using flat
and concentrating PV modules). Different electrical signals with respect to irradiance, PV module temperature and
local time were measured. DC voltage and maximum power point tracking were analysed.
Effective Mean-Field Inference Method for Nonnegative Boltzmann Machines
Creators: name: Yasuda, Muneki
Publisher: name: arXiv
Year: 2016
Subjects: subject: Machine Learning (stat.ML)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Nonnegative Boltzmann machines (NNBMs) are recurrent probabilistic neural network models that can describe multi-modal nonnegative data. NNBMs form rectified Gaussian distributions that appear in biological neural network models, positive matrix factorization, nonnegative matrix factorization, and so on. In this paper, an effective inference method for NNBMs is proposed that uses the mean-field method, referred to as the Thouless--Anderson--Palmer equation, and the diagonal consistency method, which was recently proposed.
What can the occult do for you?
Creators: name: Holwerda, B. W.
name: Keel, W. C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Interstellar dust is still a dominant uncertainty in Astronomy, limiting precision in e.g., cosmological distance estimates and models of how light is re-processed within a galaxy. When a foreground galaxy serendipitously overlaps a more distant one, the latter backlights the dusty structures in the nearer foreground galaxy. Such an overlapping or occulting galaxy pair can be used to measure the distribution of dust in the closest galaxy with great accuracy. The STARSMOG program uses Hubble to map the distribution of dust in foreground galaxies in fine (<100 pc) detail. Integral Field Unit (IFU) observations will map the effective extinction curve, disentangling the role of fine-scale geometry and grain composition on the path of light through a galaxy. The overlapping galaxy technique promises to deliver a clear understanding of the dust in galaxies: geometry, a probability function of dimming as a function of galaxy mass and radius, and its dependence on wavelength.
description: roceedings of IAU Symposium 321, "Formation and evolution of galaxy outskirts", Eds. A. Gil de Paz, J. C. Lee & J. H. Knapen, Cambridge University Press, Cambridge
The Holstein Polaron Problem Revisited
Creators: name: Tayebi, Amin
name: Zelevinsky, Vladimir
Publisher: name: arXiv
Year: 2015
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The Holstein Hamiltonian was proposed half a century ago; since then, decades of research have come up empty handed in the pursuit of a closed-form solution. An exact solution to the two-site Holstein model is presented in this paper. The obtained results provide a clear image of the Hamiltonian structure and allow for the investigation of the symmetry, energy level crossings and polaronic characteristics of the system. The main mathematical tool is a three-term recurrence relation between the wave function amplitudes that was obtained using the properties of a family of orthogonal functions, namely the Poisson-Charlier polynomials. It is shown that, with the appropriate choice of basis, the eigenfunctions of the problem naturally fall into two families (parities) associated with the discrete $\mathbb{Z}_{2}$ symmetry of the Hamiltonian. The asymptotic solution to the recurrence relation is found by using the Birkhoff expansion. The asymptotic sets the truncation criterion for the wave function, which ensures the accurate calculation of the energy levels for any strength of electron-phonon interaction. Level crossing of states with different parities is discussed and the exact points of broken symmetry are found analytically. The results are used as the building blocks for studying a four-site system. The inherited symmetries lead to the formation of a sparse matrix that is convenient for numerical calculations.
description: 9 pages, 5 figures
Floating Cast Method: a Technique to Realize High-Quality Multicrystalline Si Ingot
Creators: name: Usami, N.
name: Takahashi, I.
name: Kutsukake, K.
name: Morishita, K.
name: Nakajima, K.
Publisher: name: WIP
Year: 2011
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Silicon Feedstock, Crystallisation and Wafering

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 1986-1988
description: We show that “floating cast method”, which has been recently proposed by our group, is a promising
technique to realize high-quality multicrystalline Si (mc-Si) ingot. The floating cast method consists of nucleation at
the surface of the melt instead of inhomogeneous nucleation at the bottom of the crucible, and subsequent
solidification from the top to the bottom. Ideally, crystals can be grown while floating on the melt. The nucleation at
the surface of the melt permits us to carry out in situ observation through a view port, which facilitates to understand
growth behavior and control microstructures at the initial stage. The solidification while floating can dramatically
reduce introduction of external stress coming from the contact with the crucible wall. This is advantageous in terms
of reduction of density of crystal defects such as dislocations and sub-grain boundaries since their generation is
closely correlated with the amount of shear stress around grain boundaries, which is supposed to be proportional to
external stress.
Robustness of the Fractal Regime for the Multiple-Scattering Structure Factor
Creators: name: Katyal, Nisha
name: Botet, Robert
name: Puri, Sanjay
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: In the single-scattering theory of electromagnetic radiation, the {\it fractal regime} is a definite range in the photon momentum-transfer $q$, which is characterized by the scaling-law behavior of the structure factor: $S(q) \propto 1/q^{d_f}$. This allows a straightforward estimation of the fractal dimension $d_f$ of aggregates in {\it Small-Angle X-ray Scattering} (SAXS) experiments. However, this behavior is not commonly studied in optical scattering experiments because of the lack of information on its domain of validity. In the present work, we propose a definition of the multiple-scattering structure factor, which naturally generalizes the single-scattering function $S(q)$. We show that the mean-field theory of electromagnetic scattering provides an explicit condition to interpret the significance of multiple scattering. In this paper, we investigate and discuss electromagnetic scattering by three classes of fractal aggregates. The results obtained from the TMatrix method show that the fractal scaling range is divided into two domains: 1) a genuine fractal regime, which is robust; 2) a possible anomalous scaling regime, $S(q) \propto 1/q^δ$, with exponent $δ$ independent of $d_f$, and related to the way the scattering mechanism uses the local morphology of the scatterer. The recognition, and an analysis, of the latter domain is of importance because it may result in significant reduction of the fractal regime, and brings into question the proper mechanism in the build-up of multiple-scattering.
description: 9 pages, 4 figures, accepted for publication in Journal of Quantitative Spectroscopy and Radiative Transfer (JQSRT)
MPPT Tracking Problems in PV Modules of Partly Shaded Solar Cells
Creators: name: Grzesiak, W.
name: Klugmann-Radziemska, E.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Components for PV Systems
Balance of System Components

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 3827-3830
description: The recent development and progress in the PV theory and praxis create some problems, perhaps of secondary
importance, but significantly influencing the efficiency and overall performance of PV installations. Here typical examples
are the problems of partial shading of PV modules and arrays, as well as polluting their surfaces with dust of various origin.
The first of these effects is of special importance as endangering even the irreversible damage in form of the so called “hot
spots” on the module, being the costliest element of PV installation.
The second, here not discussed effect, may obviously reduce the nominal PV power capabilities, especially in regions of
poor cleaning rainfalls. The Authors have in their disposal special electronic sources for modeling various artificial I-U
characteristics, simulating partly shaded modules and thus often equipped with by-pass diodes. The paper presents
experiments, carried on with several market battery charge regulator types, even those of the highest class, not being able to
properly choose the optimum MPP conditions of the module’s I-U plots in the shaded regime. Some counteractive electronic
solutions have been proposed and discussed.
Algorithms for Learning Latent Models : Establishing Tractability to Approaching Optimality
Creators: name: Bakshi, Ainesh
Publisher: name: Carnegie Mellon University
Year: 2023
Subjects: Theoretical Computer Science

description: Modern machine learning relies on algorithms that fit expressive latent models to large datasets. While such tasks are easy in low dimensions, real-world datasets are truly high-dimensional, often leading to computational intractability. Additionally, a prerequisite to deploying models in real-world systems is to ensure that their behavior degrades gracefully when the modeling assumptions no longer hold. Therefore, there is a growing need for efficient algorithms that fit reliable and robust models to data and are accompanied with provable guarantees. In this thesis, we focus on designing such efficient and robust algorithms for learning latent variable models. In particular, we investigate two complementary regimes arising in learning latent models: establishing computational tractability and approaching computational optimality. The first regime considers learning highdimensional latent models where no efficient algorithms were known. We resolve several central open questions in this regime, by providing the first polynomial time algorithms for robustly learning a mixture of Gaussians, robust linear regression and learning two-layer neural networks. The second regime considers models where polynomial time algorithms were already well-established. Here, we show that we can obtain algorithms with information-theoretically minimal running time and sample complexity. In particular, we show that for several low-rank models there is no statistical vs. computational trade-off.
Simulation of the Dislocation Density During Multicrystalline Silicon Ingot Growth
Creators: name: Helbig, R.
name: Funke, C.
name: Möller, H.J.
Publisher: name: WIP
Year: 2011
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Silicon Feedstock, Crystallisation and Wafering

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 1938-1941
description: In order to determine the influence of grain boundaries and grain orientations on the generation and
multiplication of dislocations in multicrystalline silicon, a model of the dislocation generation has been designed and
numerically solved. Based on the Alexander-Haasen-Sumino model, which has been used earlier to calculate the
dislocation density, it is developed further and takes into account the multiplication of dislocations in different glide
systems, their interaction and the annihilation. This model has been solved numerically with the help of the
multiphysical software Elmer. A three-dimensional model of a multicrystalline silicon ingot has been created to show
the influence of the different grain orientations. It is shown that there exist grain orientations, which yield higher
dislocation densities, and that these dislocations are preferentially located near grain boundaries.
Hydrogen Isotope Trapping in Al-Cu Binary Alloys
Creators: name: Chao, Paul
name: Karnesky, Richard A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The trapping mechanisms for hydrogen isotopes in Al-X Cu (0.0 at.% < X < 3.5 at.%) alloys were investigated using thermal desorption spectroscopy (TDS), electrical conductivity, and differential scanning calorimetry. Constant heating rate TDS was used to determine microstructural trap energies and occupancies. In addition to the trapping states in pure Al reported in the literature (interstitial lattice sites, dislocations, and vacancies), a trap site due to Al-Cu intermetallic precipitates is observed. The binding energy of this precipitate trap is ($18\pm3$) kJ$\cdot$mol$^{-1}$ ($0.19 \pm 0.03$ eV). Typical occupancy of this trap is high; for Al-2.6 at.% Cu (a Cu composition comparable to that in AA2219) charged at 200°C with 130 MPa D$_2$ for 68 days, there is ca. there is $3.15\times10^{-7}$ mol D bound to the precipitate trap per mol of Al, accounting for a third of the D in the charged sample.
description: 29 pages, 11 figures, submitted to Materials Science & Engineering A
Two-dimensional Halide Perovskites: Tuning Electronic Activities of Defects
Creators: name: Liu, Yuanyue
name: Xiao, Hai
name: Goddard, William A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Two-dimensional (2D) halide perovskites are emerging as promising candidates for nano-electronics and optoelectronics. To realize their full potential, it is important to understand the role of those defects that can strongly impact material properties. In contrast to other popular 2D semiconductors (e.g. transition metal dichalcogenides MX2) for which defects typically induce harmful traps, we show that the electronic activities of defects in 2D perovskites are significantly tunable. For example, even with a fixed lattice orientation, one can change the synthesis conditions to convert a line defect (edge or grain boundary) from electron acceptor to inactive site without deep gap states. We show that this difference originates from the enhanced ionic bonding in these perovskites compared with MX2. The donors tend to have high formation energies, and the harmful defects are difficult to form at a low halide chemical potential. Thus we unveil unique properties of defects in 2D perovskites and suggest practical routes to improve them.
Numerical Simulation of the Effects of Different Coatings on Graphite Susceptor for the Induction Process of Polycrystalline Silicon
Creators: name: Lian, K.L.
name: Lian, S.S.
name: Cheng, S.C.
name: Tsao, S.
Publisher: name: WIP
Year: 2011
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Silicon Feedstock, Crystallisation and Wafering

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 1942-1945
description: The vacuum induction melting and control solidification is a new developed process for the
manufacture of polycrystalline silicon with the advantage of quick heating rate compared to the traditional resistance
heating method. The graphite susceptor of the induction furnace plays a key role in controlling the temperature of the
melt of polycrystal silicon for solar cells. This paper investigates how different coatings painted on the susceptor
would influence the heating efficiency and the temperature distribution of the silicon melt. A graphite susceptor is
usually coated with a thin film of insulating material to reduce heat losses and to prevent vapors such as SiO to
contaminate the susceptor. Numerical simulations show that the coating material at the outer surface of the susceptor
should be the one with low thermal conductivity to prevent heat loss. On the other hand, the coating on the inner
surface should be the material with high thermal conductivity to allow easy heat transfer.
The Wire Sawing Process of Silicon Wafers Studied by Hardness Indentations
Creators: name: Espe, B.
name: Kivambe, M.
name: Lohne, O.
Publisher: name: WIP
Year: 2011
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Silicon Feedstock, Crystallisation and Wafering

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 1959-1964
description: Wire sawing of silicon wafers using a cutting fluid consisting of PEG and SiC has developed into a
mature technology in the PV industry. Further progress in improving cutting speed and wafer quality may require a
detailed understanding of the material removal process. This work employs Vickers indentations to simulate the SiC
– Si interaction in wire sawing. The size, shape and frequency of chipping are found to be highly dependent on the
indenter’s orientation relative to the [100] direction on a (001) surface. The authors propose that this anisotropy is
founded partly in cracking behavior during loading, and partly in the formation, and relaxation, of dislocations
generated in phase transformed structures of pressure induced silicon.
Modelling and measurements of fibrinogen adsorption on positively charged microspheres
Creators: name: Żeliszewska, P.
name: Bratek-Skicki, A.
name: Adamczyk, Z.
name: Cieśla, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Adsorption of fibrinogen on positively charged microspheres was theoretically and experimentally studied. The structure of monolayers and the maximum coverage were determined by applying the experimental measurements at pH=3.5 and 9.7 for NaCl concentration in the range of $10^{-3}- 0.15$ M. The maximum coverage of fibrinogen on latex particles was precisely determined by the AFM method. Unexpectedly, at pH=3.5, where both fibrinogen molecule and the latex particles were positively charged, the maximum coverage varied between 0.9 mg m$^{-2}$ and 1.1 mg m$^{-2}$ for $10^{-2}$ and 0.15 M NaCl, respectively. On the other hand, at pH=9.7, the maximum coverage of fibrinogen was larger, varying between 1.8 mg m$^{-2}$ and 3.4 mg m$^{-2}$ for $10^{-2}$ and 0.15 M NaCl, respectively. The experimental results were quantitatively interpreted by the numerical simulations.
description: 14 pages, 8 figures
Multicriteria Optimization of the Compensated Reactive Power in the Integrated Branches of PV Power Plants
Creators: name: Nedelcheva, S.
name: Chobanov, V.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Components for PV Systems
Engineering and System Integration

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 3762-3765
description: This paper presents an algorithm for optimizing the size of the transmitted reactive power in the accession
branches of distribution networks with decentralized electricity sources. It is drawn to the target function and constraints is
formulated to solve the task. Multi optimization is held power compensating devices in function of the desirability of finding
a single parameter optimization, which is recommended for practical calculations and comparative analysis.
Privacy-Preserving Shortest Path Computation
Creators: name: Wu, David J.
name: Zimmerman, Joe
name: Planul, Jérémy
name: Mitchell, John C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: Navigation is one of the most popular cloud computing services. But in virtually all cloud-based navigation systems, the client must reveal her location and destination to the cloud service provider in order to learn the fastest route. In this work, we present a cryptographic protocol for navigation on city streets that provides privacy for both the client's location and the service provider's routing data. Our key ingredient is a novel method for compressing the next-hop routing matrices in networks such as city street maps. Applying our compression method to the map of Los Angeles, for example, we achieve over tenfold reduction in the representation size. In conjunction with other cryptographic techniques, this compressed representation results in an efficient protocol suitable for fully-private real-time navigation on city streets. We demonstrate the practicality of our protocol by benchmarking it on real street map data for major cities such as San Francisco and Washington, D.C.
description: Extended version of NDSS 2016 paper
Impact of Silicon Carbide Particle Shape on the Fracture Behavior of Silicon and the Multi-Wire Sawing Performance
Creators: name: Retsch, S.
name: Budnitzki, M.
name: Wagner, T.
name: Möller, H.J.
Publisher: name: WIP
Year: 2011
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Silicon Feedstock, Crystallisation and Wafering

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 1973-1976
description: A very costly and thus important step in the solar cell production of crystalline silicon solar cells is the
cutting of wafers. The standard technique is the multi-wire sawing with abrasive SiC slurries. Previous investigations
have shown that the wafer stability is mainly determined by subsurface micro cracks on the surface and the edges of
wafers which occur during sawing. The micro cracks are formed by the indentation of the edges and tips of silicon
carbide particles during sawing. Practical experiences show that the particle shape has an influence on the sawing
performance and the surface damage. In this investigation a new method for investigating single SiC particle
indentation events on silicon is presented. Attention is paid to the material response on arbitrary shaped tips and also
to the fact that silicon carbide particles may fracture under loading.
Flexibility to Integrate PV Modules in Buildings: MPPT Converters in PV Modules as Power Conditioning Device
Creators: name: Orduz, R.
name: Egido Aguilera, M.A.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Components for PV Systems
Engineering and System Integration

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 3770-3773
description: Frequently, architects and engineers are limited to perform the design and integration of PV modules in
buildings with circumstances as: same tilt and inclination angles, same size and electrical characteristics of PV
modules, localized dirt and shadows cast by nearby objects and others. The use of MPPT converters per module in
series association allows the individual adaptation of each panel to the load, solving part of the problems related to
integration of PV modules in buildings. This paper presents useful behavior analytical models of MPPT Converters
integrated in PV modules and connected together in series association in a typical grid-connected PV system. A
theoretical study case of the Moncloa Palace PV Pergola (Spain) in terms of annual energy simulation is examined,
taking into account in this case, a hypothetic cascade MPPT converters with different tilt and orientation angles.
Learning from the PV Crisis in the Czech Republic Related Administrative and Legal Issues
Creators: name: Bechník, B.
name: Barinka, R.
name: Pinos, J.
Publisher: name: WIP
Year: 2011
Subjects: PV Taking Off: Large-Scale Deployment
Socio Economics of PV

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 4506-4509
description: Photovoltaic boom in the Czech Republic was caused by combination of impacts: feed-in-tariff was too
profitable for large ground-mounted installations. Floating of exchange rate of national currency was not taken into account
when support scheme was designed. Systematic strengthening of the currency occurred nearly all the time. Unpredictable fall
of prices of PV was the most significant impact. It was possible to solve the problem by fast legislative changes at end of
2009. Despite of that it was announced by the Government that feed-in-tariff will be cut by 1st January 2010, it was not
realised; partly due to effective lobbying of large investors, partly due to dysfunction of the Parliament.
The Photovoltaic Reality Ahead: Terawatt Scale Market Potential Powered by Pico to Gigawatt PV Systems and Enabled by High Learning and Growth Rates
Creators: name: Breyer, C.
Publisher: name: WIP
Year: 2011
Subjects: PV Taking Off: Large-Scale Deployment
Markets for Large-scale PV

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 4391-4404
description: The photovoltaic (PV) energy technology has the potential to contribute to the global energy supply on a large scale.
This potential can only be realised if sustainable and highly competitive PV economics are achieved. An integrated
economic PV market potential assessment is presented consisting of grid-parity and fuel-parity analyses for the ongrid
markets and an amortization analysis for rural off-grid PV markets. All analyses are mainly driven by cost
projections based on the experience curve approach and growth rates for PV systems and electricity and fossil fuel
prices for the currently used power supply. A total economic PV market potential of 2,800 GW to 4,300 GW is
derived for the year 2020. 600 GW to 1,600 GW of cumulated installed PV capacity is estimated for the year 2020,
depending on scenario assumptions. Even the low edge of the expected total installed PV capacity exceeds the
scenario assumptions of leading energy organizations, such as IEA, by a factor of more than three to five. In
conclusion, PV is on its way to become a highly competitive energy technology. Being complementary to wind
power, PV together with wind power might become the backbone of the global energy supply in the coming decades.
Identification of Globular Cluster Stars in RAVE data II: Extended tidal debris around NGC 3201
Creators: name: Anguiano, B.
name: De Silva, G. M.
name: Freeman, K.
name: Da Costa, G. S.
name: Zwitter, T.
name: Quillen, A. C.
name: Zucker, D. B.
name: Navarro, J. F.
name: Kunder, A.
name: Siebert, A.
name: Wyse, R. F. G.
name: Grebel, E. K.
name: Kordopatis, G.
name: Gibson, B. K.
name: Seabroke, G.
name: Sharma, S.
name: Wojno, J.
name: Bland-Hawthorn, J.
name: Parker, Q. A.
name: Steinmetz, M.
name: Boeche, C.
name: Gilmore, G.
name: Bienayme, O.
name: Reid, W.
name: Watson, F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We report the identification of extended tidal debris potentially associated with the globular cluster NGC 3201, using the RAVE catalogue. We find the debris stars are located at a distance range of 1-7 kpc based on the forthcoming RAVE distance estimates. The derived space velocities and integrals of motion show interesting connections to NGC 3201, modulo uncertainties in the proper motions. Three stars, which are among the 4 most likely candidates for NGC 3201 tidal debris, are separated by 80 degrees on the sky yet are well matched by the 12 Gyr, [Fe/H] = -1.5 isochrone appropriate for the cluster. This is the first time tidal debris around this cluster has been reported over such a large spatial extent, with implications for the cluster$'$s origin and dynamical evolution.
description: Accepted 2016 January 8. Received 2015 December 10; in original form 2015 November 13 MNRAS
Order-/Disorder Simulations for CIGS Thin-Film Solar Cells
Creators: name: Ludwig, C.D.R.
name: Windeln, J.
name: Gruhn, T.
name: Felser, C.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Thin Film Solar Cells
CIS and Other (II-VI) Ternary Thin Film Solar Cells

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 3335-3336
description: Chalcopyrite based solar modules combine advantages of thin-film technology with the high
efficiency and stability known from conventional crystalline silicon cells. Commercial modules containing the
chalcopyrite Cu(In,Ga)Se2 (CIGS) reach efficiencies of 12%, but there is still a considerable gap to theoretical
predictions of maximum efficiencies. For closing this gap a detailed understanding of the structures that form in
the CIGS compound is crucial. Using a combination of ab initio electronic structure calculations based on density
functional theory and Monte Carlo simulations we investigate the homogeneity of the CIGS material. The ab initio
based Monte Carlo simulations indicate the formation of clusters within the CIGS material. Such spatial
inhomogeneities greatly influences the efficiency of solar cells. Our calculations show that In-rich CIGS exhibits a
higher homogeneity than Ga-rich CIGS. This mighty be an important contribution to the fact that solar cells made
from Ga-rich CIGS have lower efficiencies than cells made from In-rich CIGS.
Simulation study of a rectifying bipolar ion channel: Detailed model versus reduced model
Creators: name: Ható, Z.
name: Boda, D.
name: Gillespie, D.
name: Vrabec, J.
name: Rutkai, G.
name: Kristóf, T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We study a rectifying mutant of the OmpF porin ion channel using both all-atom and reduced models. The mutant was created by Miedema et al. [Nano Lett., 2007, 7, 2886] on the basis of the N-P semiconductor diode, in which an N-P junction is formed. The mutant contains a pore region with positive amino acids on the left-hand side and negative amino acids on the right-hand side. Experiments show that this mutant rectifies. Although we do not know the structure of this mutant, we can build an all-atom model for it on the basis of the structure of the wild type channel. Interestingly, molecular dynamics simulations for this all-atom model do not produce rectification. A reduced model that contains only the important degrees of freedom (the positive and negative amino acids and free ions in an implicit solvent), on the other hand, exhibits rectification. Our calculations for the reduced model (using the Nernst-Planck equation coupled to Local Equilibrium Monte Carlo simulations) reveal a rectification mechanism that is different from that seen for semiconductor diodes. The basic reason is that the ions are different in nature from electrons and holes (they do not recombine). We provide explanations for the failure of the all-atom model including the effect of all the other atoms in the system as a noise that inhibits the response of ions (that would be necessary for rectification) to the polarizing external field.
description: 16 pages, 10 figures
Recycling of Coolant Solutions for Diamond-Wire Based Wafer Cutting Processes
Creators: name: Berndt, R.
name: Ruth, J.
name: Waters, S.
Publisher: name: WIP
Year: 2011
Subjects: Wafer-based Silicon Solar Cells and Materials Technology
Silicon Feedstock, Crystallisation and Wafering

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 1951-1954
description: To cut wafers by means of diamond wires instead of cutting slurries may improve the cutting process itself
(e.g. higher productivity, lower energy demand, cleaner wafers [1]) as well as downstream processing and facility
operations with regard to materials, waste treatment, waste discharge and logistics. Reclaimable coolant liquids are
essential for the implementation of the new wafering method. Either alcohol, typically glycol-based coolants (ABC),
which are usually diluted with a small quantity of water, or water-based coolants (WBC), consisting primarily of water
with low concentrations of additives such as surfactants are applied. Alcohol-based coolants tolerate some particles and
need therefore only partial regeneration. On the other hand, some disadvantages such as high viscosity, limited
filterability, disposal issues for liquid waste and silicon sludge etc. erect high hurdles for on-site reclaim. Hence larger
scale use of ABCs is limited in view of downstream processing and fluid management. Water-based coolants are more
easily filtered and can be permanently reclaimed. They provide favorable prerequisites for on-site reclaim, kerf reuse, and
post-cutting operations. Therefore they are applicable for all sizes of installations from single-saw supply to mega sized
fabs of the future. Crossflow microfiltration combines perfect solids removal with excellent transmission of coolant
components as long as filtration protocols and membranes are attuned to the individual coolant. Reclaim systems for
WBCs can easily be integrated into the fluid management of wafer fabs.
The COSMOS2015 Catalog: Exploring the 1
Creators: name: Laigle, C.
name: McCracken, H. J.
name: Ilbert, O.
name: Hsieh, B. C.
name: Davidzon, I.
name: Capak, P.
name: Hasinger, G.
name: Silverman, J. D.
name: Pichon, C.
name: Coupon, J.
name: Aussel, H.
name: Borgne, D. Le
name: Caputi, K.
name: Cassata, P.
name: Chang, Y. -Y.
name: Civano, F.
name: Dunlop, J.
name: Fynbo, J.
name: kartaltepe, J. S.
name: Koekemoer, A.
name: Fevre, O. Le
name: Floc'h, E. Le
name: Leauthaud, A.
name: Lilly, S.
name: Lin, L.
name: Marchesi, S.
name: Milvang-Jensen, B.
name: Salvato, M.
name: Sanders, D. B.
name: Scoville, N.
name: Smolcic, V.
name: Stockmann, M.
name: Taniguchi, Y.
name: Tasca, L.
name: Toft, S.
name: Vaccari, M.
name: Zabl, J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We present the COSMOS2015 catalog which contains precise photometric redshifts and stellar masses for more than half a million objects over the 2deg$^{2}$ COSMOS field. Including new $YJHK_{\rm s}$ images from the UltraVISTA-DR2 survey, $Y$-band from Subaru/Hyper-Suprime-Cam and infrared data from the Spitzer Large Area Survey with the Hyper-Suprime-Cam Spitzer legacy program, this near-infrared-selected catalog is highly optimized for the study of galaxy evolution and environments in the early Universe. To maximise catalog completeness for bluer objects and at higher redshifts, objects have been detected on a $χ^{2}$ sum of the $YJHK_{\rm s}$ and $z^{++}$ images. The catalog contains $\sim 6\times 10^5$ objects in the 1.5 deg$^{2}$ UltraVISTA-DR2 region, and $\sim 1.5\times 10^5$ objects are detected in the "ultra-deep stripes" (0.62 deg$^{2}$) at $K_{\rm s}\leq 24.7$ (3$σ$, 3", AB magnitude). Through a comparison with the zCOSMOS-bright spectroscopic redshifts, we measure a photometric redshift precision of $σ_{Δz/(1+z_s)}$ = 0.007 and a catastrophic failure fraction of $η=0.5$%. At $3
description: Accepted for publication in ApJ
Enhancing the Deposition Rate of Close Spaced Sublimated Cadmium Telluride Films by Using Nanoparticles
Creators: name: Schumm, B.
name: Althues, H.
name: Kaskel, S.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Thin Film Solar Cells
CdTe Solar Cells

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 3492-3494
description: In this work the deposition behaviour of nano-structured source powders for the CSS deposition of
CdTe films was studied. Two different CdTe materials were compared in our experiments – a commercially available
bulk reference powder (particle size 2 – 100 μm) and a self-synthesized nano-structured powder (100 – 500 nm). The
latter showed a specific surface area of 4.1 m2/g while in the case of bulk CdTe the specific surface area was less
than 0.1 m2/g. SEM measurements were carried out on CSS deposited CdTe films to indicate appropriate film
thicknesses. An increase of the deposition rate by a factor of 1.7 could be determined by decreasing the particle size
of the used source material. This could be an approach for further process cost reduction in CdTe solar cell
manufacturing.
High Temperature Resistant Coatings of Transparent and Conductive Nb Doped Titania (TiO2:Nb) for Solar Cell Applications
Creators: name: Junghähnel, Ma.
name: Heimke, B.
name: Hartung, U.
name: Kopte, T.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Thin Film Solar Cells
CdTe Solar Cells

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 3495-3499
description: Niobium doped titania (TiO2:Nb) is a new n – type conducting transparent oxide (TCO). Beside the good electrical
and optical properties, TiO2:Nb is characterized by a very good high temperature resistance. A 100 nm TiO2:Nb thin
film shows after annealing in vacuum at 450°C a resistivity of 7.22 x 10-4 Ω*cm with a good transparency in the
visible range and an extinction coefficient k of 0.0197 at 550 nm. This enables the application of such TCO coatings
in the solar cell production, where high temperatures are required in the manufacturing process, e.g. for μc-Si or
CdTe solar cells. The TiO2:Nb thin films were deposited by DC and pulsed DC sputtering from a ceramic titania
target with a content of approximately 6 wt.-% Nb. We used a dynamic deposition process in a large area in - line
sputtering plant up to a substrate width of 400 mm. We investigated the influence of several process parameters on
the characteristics of the TiO2:Nb layers. The high temperature stability of the TiO2:Nb thin films was in focus of the
investigations. After the deposition of TiO2:Nb thin films a thermal annealing in the range of 450 to 500°C in vacuum
and hydrogen was performed.
The optical properties of TiO2:Nb thin films were measured by VIS/ NIR spectrometry. Hall-measurements were
used to determine the free carrier density, free carrier mobility and the resistivity. For an evaluation of the crystalline
phases of the thin films, XRD measurements were carried out.
Ca II triplet spectroscopy of RGB stars in NGC 6822: kinematics and metallicities
Creators: name: Swan, Jesse
name: Cole, Andrew A.
name: Tolstoy, Eline
name: Irwin, Mike J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present a detailed analysis of the chemistry and kinematics of red giants in the dwarf irregular galaxy NGC 6822. Spectroscopy at 8500 Angstroms was acquired for 72 red giant stars across two fields using FORS2 at the VLT. Line of sight extinction was individually estimated for each target star to accommodate the variable reddening across NGC 6822. The mean radial velocity was found to be v_helio = (52.8 +/- 2.2) km/s with dispersion rms = 24.1 km/s, in agreement with other studies. Ca II triplet equivalent widths were converted into [Fe/H] metallicities using a V magnitude proxy for surface gravity. The average metallicity was [Fe/H] = (-0.84 +/- 0.04) with dispersion rms = 0.31 dex and interquartile range 0.48. Our assignment of individual reddening values makes our analysis more sensitive to spatial variations in metallicity than previous studies. We divide our sample into metal-rich and metal-poor stars; the former are found to cluster towards small radii with the metal-poor stars more evenly distributed across the galaxy. The velocity dispersion of the metal-poor stars is higher than that of the metal-rich stars; combined with the age-metallicity relation this indicates that older populations have either been dynamically heated or were born in a less disclike distribution. The low ratio (v_rot/v_rms) suggests that within the inner 10', NGC 6822's stars are dynamically decoupled from the HI gas, possibly in a thick disc or spheroid.
description: 15 pages, 12 figures, includes tabular data