cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Exploring top-down visual pathways using micro-stimulation and its applications to cortical visual prosthesis
Creators: name: Nadolskis, Lucas
Publisher: name: Carnegie Mellon University
Year: 2023
Subjects: Biomedical Engineering not elsewhere classified

description: The search for restoring vision has focused on retinal implants or cortical implants. The latter approach has mostly focused on the stimulation of feedforward visual pathways, involving primary visual areas such as V1 and V2. These results have given us the perception of dots of light known as phosphenes, but not the complexity of natural visual perception. This is likely because visual perception is a widespread computation in the brain. Key areas that contribute to vision include higher-order visual areas such as V4, which integrates feedforward and top-down information, as well as high-order cognitive areas such as the prefrontal cortex (PFC), which controls top-down modulation such as visual attention. This work will focus on the stimulation of PFC and its effects on V4. Most precisely, on the application that such an interaction might bring to the field of visual prosthesis. We found mild but distinct effects of different PFC stimulation patterns on V4 responses, as expected from top-down mudulatory effects. This offers promissing results for future integration of this pathway in future visual neuroprosthetic devices to achieve a more holistic sense of vision. In the introduction we will revise the historical factors that lead researchers to focus on the visual cortex as the primary target for visual neuroprosthetics. To conclude, we will present our position on the current state of prosthesis and debate whether we could already use current neurotechnologies, albeit imperfect, to benefit blind people. ”XVII. Men ought to know that from the brain, and from the brain only, arise our pleasures, joys, laughter and jests, as well as our sorrows, pains, griefs and tears. Through it, in particular, we think, see, hear, and distinguish the ugly from the beautiful, the bad from the good, the pleasant from the unpleasant, in some cases using custom as a test, in others perceiving them from their utility. It is the same thing which makes us mad or delirious, inspires us with dread and fear, whether by night or by day, brings sleeplessness, inopportune mistakes, aimless anxieties, absentmindedness, and acts that are contrary to habit. These things that we suffer all come from the brain, when it is not healthy, but becomes abnormally hot, cold, moist, or dry, or suffers any other unnatural affection to which it was not accustomed. Madness comes from its moistness. When the brain is abnormally moist, of necessity it moves, and when it moves neither sight nor hearing are still, but we see or hear now one thing and now another, and the tongue speaks in accordance with the things seen and heard on any occasion. But all the time the brain is still a man is intelligent.” Hyppocrates, Sacred Disease, 400 B.C.
Cascades in interdependent flow networks
Creators: name: Scala, Antonio
name: Lucentini, Pier Giorgio De Sanctis
name: Caldarelli, Guido
name: D'Agostino, Gregorio
Publisher: name: arXiv
Year: 2015
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Systems and Control (eess.SY)
subject: FOS: Physical sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: We investigate the abrupt breakdown behavior of coupled distribution grids under load growth. This scenario mimics the ever-increasing customer demand and the foreseen introduction of energy hubs interconnecting the different energy vectors. We extend an analytical model of cascading behavior due to line overloads to the case of interdependent networks and find evidence of first order transitions due to the long-range nature of the flows. Our results indicate that the foreseen increase in the couplings between the grids has two competing effects: on the one hand, it increases the safety region where grids can operate without withstanding systemic failures; on the other hand, it increases the possibility of a joint systems' failure.
description: submitted to Physica D
Hypergraph Rank and Expansion
Creators: name: Pratt, Kevin
Publisher: name: Carnegie Mellon University
Year: 2023
Subjects: Theoretical Computer Science

description: The linear–algebraic notions of matrix rank and expansion in graphs are ubiquitous throughout computer science, with applications to algebraic complexity theory, communication complexity, and derandomization. In recent years, high–dimensional generalizations of these notions to tensors and hypergraphs have led to progress on a wide variety of problems, including the improved analysis of Markov chains, algorithms and barriers for fast matrix multiplication, and the discovery of good locally testable codes and quantum LDPC codes. Yet compared to their linear–algebraic counterparts, these notions are very poorly understood. This thesis studies such notions of tensor rank and expansion in hypergraphs and their applications to algorithm design. Our contributions are threefold. First, we give new applications of tensor rank to the area of parameterized and exact algorithms, unifying several prior algorithmic tools and obtaining faster, more space–efficient algorithms for a handful of problems. We then study algorithms for fast matrix multiplication. In this area we identify new limitations on current algorithmic approaches via connections to additive combinatorics and group theory. Finally, we give several new group–theoretic families of sparse spectral high–dimensional expanders.
Epitaxy-Free Monocrystalline Silicon Thin Film: First Steps Beyond Proof-of-Concept Solar Cells
Creators: name: Depauw, V.
name: Qiu, Y.
name: Van Nieuwenhuysen, K.
name: Gordon, I.
name: Poortmans, J.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Thin Film Solar Cells
Thin Film Crystalline Silicon Solar Cells and Wafer Equivalents

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 2843-2845
description: The “Epifree” process involves the lift-off of a high-quality monocrystalline film formed by
reorganization upon annealing of cylindrical macropore arrays in silicon, and can thus provide high-quality silicon
films for solar cells without resorting to epitaxy. Proof-of-concept cells have previously been achieved and this paper
briefly presents the latest progress, with a first development of thicker films up to 2.4 μm and the inclusion of a-Si
rear-side passivation. The efficiency of 1-μm-thin cells could be improved from 2.6 to 4.1% but the Voc stayed
limited and a-Si passivation was found unsuitable for the current cell structure. For complete information the reader
is referred to the corresponding paper published in the conference special edition of Progress in Photovoltaics:
Research and Applications.
Deep Dirichlet uncertainty for unsupervised out-of-distribution detection of eye fundus photographs in glaucoma screening
Creators: name: Araújo, Teresa
name: Aresta, Guilherme
name: Bogunovic, Hrvoje
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: The development of automatic tools for early glaucoma diagnosis with color fundus photographs can significantly reduce the impact of this disease. However, current state-of-the-art solutions are not robust to real-world scenarios, providing over-confident predictions for out-of-distribution cases. With this in mind, we propose a model based on the Dirichlet distribution that allows to obtain class-wise probabilities together with an uncertainty estimation without exposure to out-of-distribution cases. We demonstrate our approach on the AIROGS challenge. At the start of the final test phase (8 Feb. 2022), our method had the highest average score among all submissions.
description: Submitted to ISBI 2022
The Secret Lives of Cepheids: Evolution, Mass Loss, and Ultraviolet Emission of the Long-Period Classical Cepheid $l$ Carinae
Creators: name: Neilson, Hilding R.
name: Engle, Scott G.
name: Guinan, Edward F.
name: Bisol, Alexandra C.
name: Butterworth, Neil
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The classical Cepheid $l$ Carinae is an essential calibrator of the Cepheid Leavitt Law as a rare long-period Galactic Cepheid. Understanding the properties of this star will also constrain the physics and evolution of massive ($M \ge 8$ $M_\odot$) Cepheids. The challenge, however, is precisely measuring the star's pulsation period and its rate of period change. The former is important for calibrating the Leavitt Law and the latter for stellar evolution modeling. In this work, we combine previous time-series observations spanning more than a century with new observations to remeasure the pulsation period and compute the rate of period change. We compare our new rate of period change with stellar evolution models to measure the properties of $l$ Car, but find models and observations are, at best, marginally consistent. The results imply that $l$ Car does not have significantly enhanced mass-loss rates like that measured for $δ$ Cephei. We find that the mass of $l$ Car is about 8 - 10 $M_\odot$. We present Hubble Space Telescope COS observations that also differ from measurements for $δ$ Cep, and $β$ Dor. These measurements further add to the challenge of understanding the physics of Cepheids, but do hint at the possible relation between enhanced mass loss and ultraviolet emission, perhaps both due to the strength of shocks propagating in the atmospheres of Cepheids.
description: 11 pages, 6 figures, 1 table, ApJ accepted
An isogeometric finite element formulation for boundary and shell viscoelasticity based on a multiplicative surface deformation split
Creators: name: Paul, Karsten
name: Sauer, Roger A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Computer and information sciences

description: This work presents a numerical formulation to model isotropic viscoelastic material behavior for membranes and thin shells. The surface and the shell theory are formulated within a curvilinear coordinate system, which allows the representation of general surfaces and deformations. The kinematics follow from Kirchhoff-Love theory and the discretization makes use of isogeometric shape functions. A multiplicative split of the surface deformation gradient is employed, such that an intermediate surface configuration is introduced. The surface metric and curvature of this intermediate configuration follow from the solution of nonlinear evolution laws - ordinary differential equations (ODEs) - that stem from a generalized viscoelastic solid model. The evolution laws are integrated numerically with the implicit Euler scheme and linearized within the Newton-Raphson scheme of the nonlinear finite element framework. The implementation of membrane and bending viscosity is verified with the help of analytical solutions and shows ideal convergence behavior. The chosen numerical examples capture large deformations and typical viscoelasticity behavior, such as creep, relaxation, and strain rate dependence. It is also shown that the proposed formulation can be straightforwardly applied to model boundary viscoelasticity of 3D bodies.
description: In this version, parts of the introduction and conclusion are rewritten, remarks 1.1, 1.2 and 3.1 are added, the title is slightly modified, the list of highlights is updated, and minor typos are fixed
The sensitivity of past and near-future lunar radio experiments to ultra-high-energy cosmic rays and neutrinos
Creators: name: Bray, Justin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Various experiments have been conducted to search for the radio emission from ultra-high-energy particles interacting in the lunar regolith. Although they have not yielded any detections, they have been successful in establishing upper limits on the flux of these particles. I present a review of these experiments in which I re-evaluate their sensitivity to radio pulses, accounting for effects which were neglected in the original reports, and compare them with prospective near-future experiments. In several cases, I find that past experiments were substantially less sensitive than previously believed. I apply existing analytic models to determine the resulting limits on the fluxes of ultra-high-energy neutrinos and cosmic rays. In the latter case, I amend the model to accurately reflect the fraction of the primary particle energy which manifests in the resulting particle cascade, resulting in a substantial improvement in the estimated sensitivity to cosmic rays. Although these models are in need of further refinement, in particular to incorporate the effects of small-scale lunar surface roughness, their application here indicates that a proposed experiment with the LOFAR telescope would test predictions of the neutrino flux from exotic-physics models, and an experiment with a phased-array feed on a large single-dish telescope such as the Parkes radio telescope would allow the first detection of cosmic rays with this technique, with an expected rate of one detection per 140 hours.
description: 26 pages, 10 figures, 3 tables, accepted for publication in Astroparticle Physics
Connection between the semiconductor--superconductor transition and the spin-polarized superconducting phase in the honeycomb lattice
Creators: name: Cichy, Agnieszka
name: Kapcia, Konrad Jerzy
name: Ptok, Andrzej
Publisher: name: arXiv
Year: 2022
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The band structure of noninteracting fermions in the honeycomb lattice exhibits the Dirac cones at the corners of the Brillouin zone. As a consequence, fermions in this lattice manifest a semiconducting behavior below some critical value of the onsite attraction, $U_{c}$. However, above $U_{c}$, the superconducting phase can occur. We discuss an interplay between the semiconductor--superconductor transition and the possibility of realization of the spin-polarized superconductivity (the so-called Sarma phase). We show that the critical interaction can be tuned by the next-nearest-neighbor (NNN) hopping in the absence of the magnetic field. Moreover, a critical value of the NNN hopping exists, defining a range of parameters for which the semiconducting phase can emerge. In the weak coupling limit case, this quantum phase transition occurs for the absolute value of the NNN hopping equal to one third of the hopping between the nearest neighbors. Similarly, in the presence of the magnetic field, the Sarma phase can appear, but only in a range of parameters for which initially the semiconducting state is observed. Both of these aspects are attributed to the Lifshitz transition, which is induced by the NNN hopping as well as the external magnetic field.
description: 7 pages, 3 figures
Pressure-induced structural phase transition of vanadium: A revisit from the perspective of ensemble theory
Creators: name: Ning, Bo-Yuan
name: Ning, Xi-Jing
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: For realistic crystals, the free energy strictly formulated in ensemble theory can hardly be obtained because of the difficulty in solving the high-dimension integral of the partition function, the dilemma of which makes it even a doubt if the rigorous ensemble theory is applicable to phase transitions of condensed matters. In the present work, the partition function of crystal vanadium under compression up to $320$ GPa at room temperature is solved by an approach developed very recently, and the derived equation of state is in a good agreement with all the experimental measurements, especially the latest one covering the widest pressure range up to $300$ GPa. Furthermore, the derived Gibbs free energy proves the very argument to understand most of the experiments reported in the past decade on the pressure-induced phase transition, and, especially, a novel phase transition sequence concerning three different phases observed very recently and the measured angles of two phases agree with our theoretical results excellently.
description: 5pages, 5figures
Reduction Effect of Fuel Consumption of a Diesel Generator by Introduction of a Stand-Alone Concentrator PV/Diesel/Battery System
Creators: name: Kemmoku, Y.
name: Araki, K.
name: Miyazaki, Y.
name: Hiramatsu, M.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Advanced Photovoltaics
Terrestrial Concentrator Systems

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 782-785
description: A diesel generator system that is independent of the electric power system supplies electric power to a
customer on an isolated island. In this study, the reduction effect of fuel consumption of the diesel generator is
investigated by introducing a stand-alone concentrator PV(CPV)/diesel/battery system on an isolated island. In this
study, the optimum operation schedule of the generator is determined by dynamic programming (DP) using data on
the electric load and CPV output, and then, the annual fuel consumption is calculated. The results show that the
annual fuel consumption increases on increasing the battery capacity, because of the charge/discharge energy loss.
On the other hand, the CPV system effectively reduces the annual fuel consumption when its capacity is less than
20%.
Can the fluctuations of the motion be used to estimate performance of kayak paddlers?
Creators: name: Vadai, Gergely
name: Gingl, Zoltan
Publisher: name: arXiv
Year: 2015
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: Today many compact and efficient on-water data acquisition units help the modern coaching by measuring and analyzing various inertial signals during kayaking. One of the most challenging problems is how these signals can be used to estimate performance and to develop the technique. Recently we have introduced indicators based on the fluctuations of the inertial signals as promising additions to the existing parameters. In this work we report about our more detailed analysis, compare new indicators and discuss the possible advantages of the applied methods. Our primary aim is to draw the attention to several exciting and inspiring open problems and to initiate further research even in several related multidisciplinary fields. More detailed information can be found on a dedicated web page, http://www.noise.inf.u-szeged.hu/kayak.
Development of an In-Line Capable Sputtering Process of Silicon Nitride for Crystalline Silicon Solar Cells
Creators: name: Scholz, S.
name: Voser, S.
name: Dovids, G.
name: Haverkamp, H.
name: Hahn, G.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Wafer-Based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Cells and Materials, Processing Technology of

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1717-1719
description: The purpose of this work is to develop a high rate sputtering process for the deposition of silicon nitride antireflection coatings for crystalline silicon solar cells. Our goal is to achieve a cycle time that allows for the processing of single wafers without a reduction of the production line throughput. We have varied several processing parameters such as process gas composition and individual gas flows into the process chamber as well as different deposition rates. In order to assess the performance of the deposited layers with respect to their passivation quality complete cells were processed on monocrystalline Czochralski wafers (125x125 mm2). We have found that the implementation of molecular hydrogen as a process gas has a detrimental effect on the passivation quality of the deposited layers. Furthermore, a clear influence of the sputtering rate on the overall cell performance can be seen. We have achieved a cell efficiency of 17.5% applying a standard screen printed process.
Development of Front Silver Paste for Producing Fine Lines and High Quality Contacts to 100 Ω/sq Emitters With Low Surface Phosphorus Concentration
Creators: name: Ebong, A.
name: Upadhyaya, A.
name: Rohatgi, A.
name: Zhang, W.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Wafer-Based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Cells and Materials, Processing Technology of

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1713-1716
description: The requirements for achieving 20% screen-printed crystalline silicon solar cell include; high sheet resistance emitter (~100 Ω/sq), <4% shadowing loss and >0.780 fill factor. However, it is challenging to achieve >0.78 fill factor on ~100 Ω/sq emitter because of the high series resistance. Although screen-printed contacts can be made to ~100 Ω/sq emitter with high surface phosphorus concentration, the efficiency is low because of the high emitter dark saturation current. Therefore only the high sheet resistance emitters with low phosphorus surface concentration can improve the screen-printed solar cell efficiency. It is the objective of this study to explore the front silver paste that can print narrow (<100 μm) and tall (>15 μm) fingers, and form high quality contacts to high sheet resistance emitters with low phosphorus surface concentrations. We have achieved efficiency of 17.6% and 76.7% fill factor through ~101μm wide and ~20 μm tall fingers on 2.5 Ω-cm, 149-cm2 Cz silicon with 100 Ω/sq emitters after a short dip in silver plating solution. Open circuit voltage of 632 mV and short circuit current of 36.3 mA/cm2 is a fingerprint of high sheet resistance emitter. This shows improvements of >7 mV in Voc and >0.3mA/cm2 in short circuit current density compared to cells with 55-65 Ω/sq emitters currently used by the industry.
What is controlling the fragmentation process in the Infrared Dark Cloud G14.225-0.506? Differet level of fragmentation in twin hubs
Creators: name: Busquet, G.
name: Estalella, R.
name: Palau, A.
name: Liu, H. B.
name: Zhang, Q.
name: Girart, J. M.
name: de Gregorio-Monsalvo, I.
name: Pillai, T.
name: Anglada, G.
name: Ho, P. T. P.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present observations of the 1.3 mm continuum emission toward hub-N and hub-S of the infrared dark cloud G14.225-0.506 carried out with the Submillimeter Array, together with observations of the dust emission at 870 and 350 microns obtained with APEX and CSO telescopes. The large scale dust emission of both hubs consists of a single peaked clump elongated in the direction of the associated filament. At small scales, the SMA images reveal that both hubs fragment into several dust condensations. The fragmentation level was assessed under the same conditions and we found that hub-N presents 4 fragments while hub-S is more fragmented, with 13 fragments identified. We studied the density structure by means of a simultaneous fit of the radial intensity profile at 870 and 350 microns and the spectral energy distribution adopting a Plummer-like function to describe the density structure. The parameters inferred from the model are remarkably similar in both hubs, suggesting that density structure could not be responsible in determining the fragmentation level. We estimated several physical parameters such as the level of turbulence and the magnetic field strength, and we found no significant differences between these hubs. The Jeans analysis indicates that the observed fragmentation is more consistent with thermal Jeans fragmentation compared with a scenario that turbulent support is included. The lower fragmentation level observed in hub-N could be explained in terms of stronger UV radiation effects from a nearby HII region, evolutionary effects, and/or stronger magnetic fields at small scales, a scenario that should be further investigated.
description: 14 pages, 5 figures. Accepted for publication in ApJ
Assessing lepton-flavour non-universality from $B\to K^*\ell\ell$ angular analyses
Creators: name: Capdevila, Bernat
name: Descotes-Genon, Sebastien
name: Matias, Joaquim
name: Virto, Javier
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The $B\to K^*μμ$ decay exhibits deviations with respect to Standard Model expectations and the measurement of the ratio $R_K$ hints at a violation of lepton-flavour universality in $B\to K\ell\ell$ transitions. Both effects can be understood in model-independent fits as a short-distance contribution to the Wilson coefficient $C_{9μ}$, with some room for similar contributions in other Wilson coefficients for $b\to sμμ$ transitions. We discuss how a full angular analysis of $B\to K^*ee$ and its comparison with $B\to K^*μμ$ could improve our understanding of these anomalies and help confirming their interpretation in terms of short-distance New Physics. We discuss several observables of interest in this context and provide predictions for them within the Standard Model as well as within several New Physics benchmark scenarios. We pay special attention to the sensitivity of these observables to hadronic uncertainties from SM contributions with charm loops.
description: 38 pages, 8 figures
General complex envelope solutions of coupled-mode optics with quadratic or cubic nonlinearity
Creators: name: Hesketh, Graham D
Publisher: name: arXiv
Year: 2015
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The analytic general solutions for the complex field envelopes are derived using Weierstrass elliptic functions for two and three mode systems of differential equations coupled via quadratic $χ_2$ type nonlinearity as well as two mode systems coupled via cubic $χ_3$ type nonlinearity. For the first time, a compact form of the solutions is given involving simple ratios of Weierstrass sigma functions (or equivalently Jacobi theta functions). A Fourier series is also given. All possible launch states are considered. The models describe sum and difference frequency generation, polarization dynamics, parity-time dynamics and optical processing applications.
Policy Options for Smart Subsidies in Malawi
Creators: name: Chadza, William
name: Duchoslav, Jan
Publisher: name: Unknown
Year: 2022
Subjects: subject: Agricultural and Food Policy
subject: Food Security and Poverty
subject: International Development
subject: Subsidy
subject: Fertilizer
subject: Cash transfer
subject: Agriculture
subject: Malawi

description: Key Messages • The impact of input subsidies can be improved by focusing on efforts to increase the rate at which inputs are converted to outputs. • Some of the least productive farming households cannot make profitable use of subsidized inputs and can be better assisted by social safety net programs such as cash transfers.
Long wavelength properties of phase field crystal models with second order dynamics
Creators: name: Heinonen, V.
name: Achim, C. V.
name: Ala-Nissila, T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The phase field crystal (PFC) approach extends the notion of phase field models by describing the topology of the microscopic structure of a crystalline material. One of the consequences is that local variation of the interatomic distance creates an elastic excitation. The dynamics of these excitations poses a challenge: pure diffusive dynamics cannot describe relaxation of elastic stresses that happen through phonon emission. To this end, several different models with fast dynamics have been proposed. In this article we use the amplitude expansion of the PFC model to compare the recently proposed hydrodynamic PFC amplitude model with two simpler models with fast dynamics. We compare these different models analytically and numerically. The results suggest that in order to have proper relaxation of elastic excitations, the full hydrodynamical description of the PFC amplitudes is required.
description: 10 pages, 7 figures
Formation of a Laser-Crystallized Silicon Seed Layer for Polycrystalline Thin Film Solar Cells
Creators: name: Weizman, M.
name: Klimm, C.
name: Nittel, M.
name: Kastner, M.
name: Hernandez, C.
name: Nickel, N.H.
name: Sontheimer, T.
name: Rech, B.
Publisher: name: WIP-Munich
Year: 2010
Subjects: Thin Film Solar Cells
Thin Film Crystalline Silicon Solar Cells and Wafer Equivalents

description: 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 2828-2831
description: The aim of this study was to investigate to which extend introducing a laser-crystallized seed layer into
a polycrystalline silicon thin film solar cell can be beneficial for this device. The seed layers were prepared with a
pulsed excimer laser on SiN coated glass and exhibit an enhancement in the grain size at the transition between
partial and complete melting of the layer, which is also known as the super lateral growth (SLG) effect. Two
approaches to perform epitaxial thickening of the seed layers and form solar cells were tested. The first was direct
epitaxy during deposition at elevated temperatures and the second was solid phase epitaxy (SPE) after depositing the
Si as amorphous material. The results show a clear correlation between the microstructure of the seed layer and the
performance of the solar cells.
Compositeness of S-wave weakly-bound states from next-to-leading order Weinberg's relations
Creators: name: Albaladejo, M.
name: Nieves, J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We discuss a model-independent estimator of the likelihood of the compositeness of a shallow S-wave bound or virtual state. The approach is based on an extension of Weinberg's relations in Phys. Rev. 137, B672 (1965) and it relies only on the proximity of the energy of the state to the two-hadron threshold to which it significantly couples. The scheme only makes use of the experimental scattering length and the effective range low energy parameters, and it is shown to be fully consistent for predominantly molecular hadrons. As explicit applications, we analyse the case of the deuteron, the $^1{\rm S}_0$ nucleon-nucleon virtual state and the exotic $D^{\ast}_{s0}(2317)^\pm$, and find strong support to the molecular interpretation in all cases. Results are less conclusive for the $D^{\ast}_{s0}(2317)^\pm$, since the binding energy of this state is significantly higher than that of the deuteron, and the approach employed here is at the limit of its applicability. We also qualitatively address the case of the recently discovered $T_{cc}^+$ state, within the isospin limit to avoid the complexity of the very close thresholds $D^0D^{\ast +}$ and $D^+D^{\ast 0}$, which could mask the ingredients of the approach proposed in this work.
description: Reviewed version matching the published one
Life-Cycle Assessment of Crystalline Silicon PV Modules Production by REC
Creators: name: Alsema, E.A.
Publisher: name: WIP-Munich
Year: 2009
Subjects: PV Deployment
Enablers for PV Development and Benefits of PV

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 4525-4529
description: A Life Cycle Assessment has been made for REC modules based on company data over the production
chain from solar grade silicon to a finished module. Based on the present data and assumptions a greenhouse gas
emission of 486 kg CO2-eq per kWp (108 kg per module) is found. The Total Energy Demand was found to be 18.2
GJ/kWp (4.0 GJ per module), while Non-Renewable Energy Demand was 8.3 GJ/kWp (1.8 GJ per module).
Based on these results an Energy Pay-Back Time of 1.35 year may be realized with a typical roof-top system in
South-Europe (irradiation 1700 kWh/m2/yr), while life-cycle GHG emissions for such a system would be just below
16 g/kWh. Switching to silicon production by means of the Fluidized Bed Reactor process, as is expected to occur in
the course of 2009, would reduce the Energy Pay-Back time to 1.04 year, but would not change GHG emissions or
other impacts.
Protoplanetary Disks in the Orion OMC1 Region Imaged with ALMA
Creators: name: Eisner, J. A.
name: Bally, J. M.
name: Ginsburg, A.
name: Sheehan, P. D.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present ALMA observations of the Orion Nebula that cover the OMC1 outflow region. Our focus in this paper is on compact emission from protoplanetary disks. We mosaicked a field containing $\sim 600$ near-IR-identified young stars, around which we can search for sub-mm emission tracing dusty disks. Approximately 100 sources are known proplyds identified with HST. We detect continuum emission at 1 mm wavelengths towards $\sim 20\%$ of the proplyd sample, and $\sim 8\%$ of the larger sample of near-IR objects. The noise in our maps allows 4$σ$ detection of objects brighter than $\sim 1.5$ mJy, corresponding to protoplanetary disk masses larger than 1.5 M$_{\rm J}$ (using standard assumptions about dust opacities and gas-to-dust ratios). None of these disks are detected in contemporaneous CO(2-1) or C$^{18}$O(2-1) observations, suggesting that the gas-to-dust ratios may be substantially smaller than the canonical value of 100. Furthermore, since dust grains may already be sequestered in large bodies in ONC disks, the inferred masses of disk solids may be underestimated. Our results suggest that the distribution of disk masses in this region is compatible with the detection rate of massive planets around M dwarfs, which are the dominant stellar constituent in the ONC.
description: Accepted for publication in ApJ
Canada: The World’s Next Booming PV Market?
Creators: name: Antonopoulos, A.
Publisher: name: WIP-Munich
Year: 2009
Subjects: PV Deployment
Markets for PV Systems

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 4505-4510
description: Due to the Green Energy Act of May 2009, the Government of Ontario, Canada will implement North
America’s first comprehensive feed-in tariff program similar to ones in Europe. With insolation in many areas of the
province on par with central Italy, the potential for solar photovoltaic projects is enormous. The paper examines the
potential development of solar PV in Ontario and Canada as a result of the feed-in tariffs. The technical, economic,
and socio-political factors of solar projects are discussed in detail. Our analysis indicates that solar PV projects in
Ontario may have the potential to be profitable, but much depends on the future value of the Canadian dollar, future
interest rate levels, the availability of debt, and future equipment costs. Despite the challenges ahead, solar PV in
Ontario could certainly boom as a result of the feed-in tariff, and as a result potentially influence other Canadian
provinces and U.S. states to adopt similar measures.
Gravitational Waves from Quasi-stable Strings
Creators: name: Lazarides, George
name: Maji, Rinku
name: Shafi, Qaisar
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We estimate the stochastic gravitational wave spectrum emitted from a network of cosmic strings in which the latter are effectively stable against breaking by monopole pair creation. The monopoles are produced at a higher scale from an earlier symmetry breaking and experience significant inflation before reentering the horizon. This gives rise to monopole-antimonopole pairs connected by string segments and the string loop formation essentially ceases. As a consequence, the lower frequency portion of the gravitational wave spectrum is suppressed relative to the no-inflation case with stable strings, which evades the stringent PPTA bound on the dimensionless string tension $Gμ$. We display the modified spectrum, accessible in the ongoing and future experiments, for $Gμ$ values in the range $10^{-10} - 10^{-15}$. We show how this `quasi-stable' string network is realized in realistic grand unified theories.
description: 18 pages, 7 figures, published version
Inhomogeneities in Silicon-Based Back-Contact Concentrator Photovoltaic Devices
Creators: name: Munji, M.K.
name: Van Dyk, E.E.
name: Vorster, F.J.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Advanced Photovoltaics
Terrestrial Concentrator Systems

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 717-720
description: Non-uniformities in silicon-based back point contact concentrator solar cells give rise to localized
variation in cell current-voltage (I-V) characteristics. Two Light Beam Induced Current (LBIC) scanning systems
were used to measure I-V plots of a concentrator cell as a function of position. Parameters were extracted using a fast
curve fitting routine for each measured I-V-data curve.
Together with a conventional He-Ne laser based LBIC system, the development of the solar LBIC (S-LBIC)
measurement technique has provided a good indication of back point contact concentrator cell performance. The SLBIC
system uses a focused concentrated light source that is directed onto a point of a concentrator cell that is under
voltage bias. Scanning the light beam over the concentrator cell allowed measurement of cell I-V plots as a function
of position. The S-LBIC technique demonstrates that several factors that reduce the solar cell efficiency can be traced
to specific local-area features. Possible recombination centres within the lightly doped n-type bulk region and close
to the point contacts were identified. We present the resulting surface maps of the extracted electrical parameters.
Finite-depth scaling of infinite quantum circuits for quantum critical points
Creators: name: Jobst, Bernhard
name: Smith, Adam
name: Pollmann, Frank
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The scaling of the entanglement entropy at a quantum critical point allows us to extract universal properties of the state, e.g., the central charge of a conformal field theory. With the rapid improvement of noisy intermediate-scale quantum (NISQ) devices, these quantum computers present themselves as a powerful tool to study critical many-body systems. We use finite-depth quantum circuits suitable for NISQ devices as a variational ansatz to represent ground states of critical, infinite systems. We find universal finite-depth scaling relations for these circuits and verify them numerically at two different critical points, i.e., the critical Ising model with an additional symmetry-preserving term and the critical XXZ model.
description: 9 pages, 5 figures (+ appendix 6 pages, 6 figures); published version
GaSb Structures with Quantum Dots in Space Charge Region
Creators: name: Andreev, V.M.
name: Kalinovsky, V.S.
name: Levin, R.V.
name: Pushniy, B.V.
name: Rumyantsev, V.D.
Publisher: name: WIP-Munich
Year: 2009
Subjects: Advanced Photovoltaics
Terrestrial Concentrator Systems

description: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 740-742
description: In the paper, an attempt is described to increase conductivity and to exclude the effect of the tunnel
junction on the multi-junction solar cells (MJSC) characteristics. Investigations have been carried out on creation of
p+- n+ and p-n junctions, as connecting elements in a MJSC, in the space charge region (SCR) of which a layer of
quantum dots (QD) is introduced. Epitaxial GaSb - based structures were fabricated by the MOCVD technique. In
p-n junctions with quantum dots, a significant (by three orders of magnitude) increase of the forward current has
been observed, which can be explained by formation the local channels for the charge carrier flow. It has been
observed the reduction of the resistance of the I-V characteristic forward branch in p+-n+ junctions with QDs more
than in 2 times compared with that in p+-n+ junctions without QDs.
Adaptive Integrand Decomposition in parallel and orthogonal space
Creators: name: Mastrolia, Pierpaolo
name: Peraro, Tiziano
name: Primo, Amedeo
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We present the integrand decomposition of multiloop scattering amplitudes in parallel and orthogonal space-time dimensions, $d=d_\parallel+d_\perp$, being $d_\parallel$ the dimension of the parallel space spanned by the legs of the diagrams. When the number $n$ of external legs is $n\le 4$, the corresponding representation of the multiloop integrals exposes a subset of integration variables which can be easily integrated away by means of Gegenbauer polynomials orthogonality condition. By decomposing the integration momenta along parallel and orthogonal directions, the polynomial division algorithm is drastically simplified. Moreover, the orthogonality conditions of Gegenbauer polynomials can be suitably applied to integrate the decomposed integrand, yielding the systematic annihilation of spurious terms. Consequently, multiloop amplitudes are expressed in terms of integrals corresponding to irreducible scalar products of loop momenta and external momenta. We revisit the one-loop decomposition, which turns out to be controlled by the maximum-cut theorem in different dimensions, and we discuss the integrand reduction of two-loop planar and non-planar integrals up to $n=8$ legs, for arbitrary external and internal kinematics. The proposed algorithm extends to all orders in perturbation theory.
description: 64 pages, 4 figures, 8 tables
Magnetic Flux Leakage techniques for detecting corrosion of pipes
Creators: name: Sathappan, Nagu
Publisher: name: London South Bank University
Year: 2022

description: Oil and gas pipelines are subjected to corrosion due to harsh environmental conditions as in refinery and thermal power plants. Interesting problems such as internal and external corrosion, emerging from the increasing demand for pipeline protection have prompted this study. Thus, early detection of faults in pipes is essential to avoid disastrous outcomes. The research work presented in this thesis comprises investigations into the use of magnetic flux leakage (MFL) testing for pipe in extreme (underwater and high temperature) conditions. The design of a coil sensor (ferrite core with coil) with a magnetic circuit is carried out for high temperature conditions. The sensor thus developed lays the ground for non-destructive evaluation (NDE) of flaws in pipes through the MFL technique. The research focusses on the detection and characterization of MFL distribution caused by the loss of metal in ferromagnetic steel pipes. Experimental verifications are initially conducted with deeply rusted pipe samples of varying thicknesses in air. AlNiCo magnets are used along with Giant Magneto Resistance (GMR) sensor (AA002-02). The experiment is further repeated for saltwater conditions in relation to varying electrical conductivity with radio frequency identification (RFID) technique. A further study carried out in the research is the correlation between magnetic and underwater data communication. The study has resulted in the development and experimental evaluation of a coil sensor with its magnetic response at room and high temperatures. This makes the system effective under high temperature conditions where corrosion metal loss needs to be determined.
Effect of Iron-Boron Pairs on Crystalline Silicon Solar Cells
Creators: name: Lauer, K.
name: Laades, A.
name: Lawerenz, A.
name: Bähr, M.
name: Maier, C.
name: Andrä, G.
name: Sachse, C.
Publisher: name: WIP-Munich
Year: 2008
Subjects: Wafer-Based Silicon Solar Cells and Materials Technology
Mono- and Multicrystalline Silicon Cells and Materials, Processing Technology of

description: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 1660-1663
description: In this contribution the impact of iron-boron pairs on silicon solar cells is investigated by numerical simulations and experiments. The parameters of a typical industrial solar cell are simulated in dependence of the iron boron pair contamination level and during the iron-boron-pair dissociation. A detrimental impact of the iron-boron pairs on the solar cell efficiency is found above a contamination level of about [Fei] = 1011 cm-3. The results of the numerical simulation are compared to open circuit voltage measurements of illuminated p-n-junctions on iron contaminated boron doped silicon samples. For the first time the effect of the iron-boron-pair dissociation on the open circuit voltage is experimentally observed. This is confirmed by the appearance of a crossover point and by comparison to quasi-steady-state photoconductance measurements. To preserve interstitial iron in the silicon while forming the p-n-junction, gettering by the high temperature phosphorous diffusion step is avoided using a laserdoping method.
Lattice instability, anharmonicity and Raman spectra of BaO under high pressure: A first principles study
Creators: name: Lavanya, K.
name: Yedukondalu, N.
name: Roshan, S. C. Rakesh
name: Dabhi, Shweta D.
name: Sripada, Suresh
name: Sainath, M.
name: Ehm, Lars
name: Parise, John B.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Alkaline-earth metal oxides, in particular MgO and CaO dominate Earths lower mantle, therefore, exploring high pressure behavior of this class of compounds is of significant geophysical research interest. Among all these compounds, BaO exhibits rich polymorphism in the pressure range of 0-1.5 Mbar. Static enthalpy calculations revealed that BaO undergoes a pressure induced structural phase transition from NaCl-type (B1) $\rightarrow$ NiAs-type (B8) $\rightarrow$ distorted CsCl-type (d-B2) $\rightarrow$ CsCl-type (B2) at 5.1, 19.5, 120 GPa respectively. B1 $\rightarrow$ B8 $\&$ B8 $\rightarrow$ d-B2 transitions are found to be first order in nature whereas d-B2$\rightarrow$ B2 is a second order or weak first order phase transition. Interestingly, d-B2 phase shows stability over a wide pressure range, $\sim$19.5-113 GPa. Mechanical and dynamical stabilities of ambient and high pressure phases are demonstrated through computed elastic constants and phonon dispersion curves, respectively. Under high pressure, significant phonon softening and soft phonon mode along M-direction are observed for B8, d-B2 and B2 phases, respectively. Pressure dependent Raman spectra suggest a phase transition from d-B2 to Raman inactive phase under pressure. Overall, the present study provides a comprehensive understanding of underlying mechanisms behind pressure-induced structural phase transitions in BaO.