cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Electrospun polylactic acid/date palm polyphenol extract nanofibres for tissue engineering applications
Creators: name: Zadeh, Khadija M.
name: Luyt, Adriaan S.
name: Zarif, Lubna
name: Augustine, Robin
name: Hasan, Anwarul
name: Messori, Massimo
name: Hassan, Mohammad K.
name: Yalcin, Huseyin C.
Publisher: name: Manara - Qatar Research Repository
Year: 2022
Subjects: subject: Environmental engineering
subject: FOS: Environmental engineering

description: In this study, a set of polylactic acid (PLA)/polyphenol extracted from date palm fruit (DP) blends were prepared by electrospinning process to be used as cell culture scaffolds for tissue engineering applications. For this purpose, PLA/DP blends with variable composition were dissolved in dichloromethane/dimethylformamide (70:30, v/v) mixture and then electrospun to obtain the fibres. Contact angle measurements, dynamic mechanical analysis, mechanical tensile and scanning electron microscopy (SEM) tools were used to study the physico-mechanical properties of the electrospun scaffolds. The results revealed that scaffolds became more hydrophilic with addition of DP. Increasing the polyphenol concentration caused the tensile strength and Young’s modulus to decrease. The SEM graphs indicated a decrease in fibre diameter with increasing DP content. In addition, it was found that both cell proliferation and cell viability were enhanced with increased DP concentration within the scaffolds. The scratch test shows that there is an enhancement in cell migration through the scratch for PLA/DP scaffolds; again, higher DP content resulted better migration. Our results suggest that improved mechanical properties, decreased fibre diameter and enhanced hydrophilicity with addition of DP improved cell migration and cell adhesion for the scaffolds. Overall, these results demonstrate that DP is a potential natural cell-friendly product for tissue engineering applications such as tissue regeneration or wound healing assays.Other Information Published in: Emergent Materials
 License: https://creativecommons.org/licenses/by/4.0
See article on publisher's website: http://dx.doi.org/10.1007/s42247-019-00042-8
Implicit equations of non-degenerate rational Bezier quadric triangles
Creators: name: Canton, A.
name: Fernandez-Jambrina, L.
name: Maria, E. Rosado
name: Vazquez-Gallo, M. J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Graphics (cs.GR)
subject: Numerical Analysis (math.NA)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: 65D17

description: In this paper we review the derivation of implicit equations for non-degenerate quadric patches in rational Bezier triangular form. These are the case of Steiner surfaces of degree two. We derive the bilinear forms for such quadrics in a coordinate-free fashion in terms of their control net and their list of weights in a suitable form. Our construction relies on projective geometry and is grounded on the pencil of quadrics circumscribed to a tetrahedron formed by vertices of the control net and an additional point which is required for the Steiner surface to be a non-degenerate quadric.
description: 10 pages, 8th International Conference Curves and Surfaces, Paris, France, June 12-18, 2014
Analysing the Effect of Snow on the PV Regulator Response in a Simple PV System
Creators: name: Solis, J.
name: Hamanee, S.
name: Nilsson, M.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Operation, Performance and Maintenance of PV Systems

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1984-1987
description: During the winter seasons, there is not only the challenge of removing snow downfall on PV solar cell
roofs in order to maximize the solar energy efficiency, but it is also to indicate when the effect of snow significantly
affects the operation in order to decide to take an action. Up to know, the study of the optical properties of snow have
been examined, including shading patterns on photovoltaic solar panels. However, while the snow cover might
reduce electricity, it might not have been significant effect due to the lack of solar radiation in the Nordic countries.
In this paper, the authors have focused to propose an experimental methodology to analyze the effect of the thickness
of the snow on a PV regulator response based on the frequency, statistical and production analyses in a simple PV
solar cell module. In order to study the effect of the electrical production in relation to the thickness of the snow and
light conditions, a set of experiments were proposed with the LEGO® PV system.
AgCuB nanoparticle eradicates intracellular S. aureus infection in bone cells: in vitro
Creators: name: Qadri, Shahnaz
name: Abdulrehman, Tahir
name: Azzi, Jamil
name: Mansour, Said
name: Haik, Yousef
Publisher: name: Manara - Qatar Research Repository
Year: 2022
Subjects: subject: Environmental engineering
subject: FOS: Environmental engineering

description: Staphylococcus aureus is the leading cause of internalized bone infection. Internalized bacteria are shielded from the immune system and antibiotics causing complications of conventional antibiotic treatment. In this study, we investigate silver-copper-boron (AgCuB) nanoparticles (NPs) as a potential alternative to eradicate internalized bacterial infection without causing a harming effect on the host cells. The antimicrobial property, as well as the toxicity of the AgCuB NP’s, is reported as dose-dependent between 0 and 20 μg/ml. Our results showed that 1–5 μg/ml of AgCuB NPs significantly reduced internalized infection in osteoblast cells with a single dose of treatment. The host cell toxicity observed at 20 μg/ml is ten times higher than the effective antimicrobial dose.Other Information Published in: Emergent Materials
 License: https://creativecommons.org/licenses/by/4.0
See article on publisher's website: http://dx.doi.org/10.1007/s42247-019-00035-7
Subparsec-scale dynamics of a dusty gas disk exposed to anisotropic AGN radiation with frequency-dependent radiative transfer
Creators: name: Namekata, Daisuke
name: Umemura, Masayuki
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We explore the gas dynamics near the dust sublimation radius of active galactic nucleus (AGN). For the purpose, we perform axisymmetric radiation hydrodynamic simulations of a dusty gas disk of radius $\approx 1\,\mathrm{pc}$ around a supermassive black hole of mass $10^{7}\,\mathrm{M_{\odot}}$ taking into account (1) anisotropic radiation of accretion disk, (2) X-ray heating by corona, (3) radiative transfer of infrared (IR) photons reemitted by dust, (4) frequency dependency of direct and IR radiations, and (5) separate temperatures for gas and dust. As a result, we find that for Eddington ratio $\approx 0.77$, a nearly neutral, dense ($\approx 10^{6\operatorname{-}8}\;\mathrm{cm^{-3}}$), geometrically-thin ($h/r<0.06$) disk forms with a high velocity ($\approx 200 \sim 3000\;\mathrm{km/s}$) dusty outflow launched from the disk surface. The disk temperature is determined by the balance between X-ray heating and various cooling, and the disk is almost supported by thermal pressure. Contrary to \citet{krolik07:_agn}, the radiation pressure by IR photons is not effective to thicken the disk, but rather compresses it. Thus, it seems difficult for a radiation-supported, geometrically-thick, obscuring torus to form near the dust sublimation radius as far as the Eddington ratio is high ($\sim 1$). The mass outflow rate is $0.05$-$0.1\;\mathrm{M_{\odot}}/\mathrm{yr}$ and the column density of the outflow is $N_{\mathrm{H}}\lesssim 10^{21}\;\mathrm{cm^{-2}}$. To explain observed type-II AGN fraction, it is required that outflow gas is extended to larger radii ($r\gtrsim 10\;\mathrm{pc}$) or that a denser dusty wind is launched from smaller radii ($r\sim 10^{4}\;R_{g}$).
description: 40 pages, 33 figures, 7 tables; accepted for publication in Monthly Notices of the Royal Astronomical Society
Photovoltaic System Equipped with Flat Reflectors: New MPPT Model in Case of Non-Uniform Illumination on PV Modules
Creators: name: Abdel Nour, C.
name: Migan-Dubois, A.
name: Badosa, J.
name: Bourdin, V.
name: Marchand, C.
name: Akiki, T.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Design and Installation of PV Systems

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1924-1928
description: This study presents a new Maximum Power Point Tracking (MPPT) model developed with MATLAB/SIMULINK based on P&O algorithm. This MPPT model takes into account the activation of bypass diodes since it will be used for the simulation of photovoltaic (PV) power plants equipped with flat reflectors.
In order to validate the proposed simulation tool, we have compared our model to experimental measurements realized without and with flat reflectors. The resulting absolute error can be lower than 3.6% for single days either with or without reflectors under stable sky conditions, whereas during one full month (November 2017), for the installation without reflectors, the absolute error was about 4.76%.
In addition to these low errors found, the proposed MPPT model allows simulation for long periods of time, months to years, with a simulation time considerably fast.
Detailed Calculation of Electrical Mismatch Losses for Central- and String-Inverter Configurations on Utility-Scale PV Arrays
Creators: name: Herrerías Azcué, M.
name: Capdevila, H.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Design and Installation of PV Systems

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1973-1978
description: The object of this study is to provide an objective answer to the question of whether significant performance
improvements can be expected when using distributed (i.e. string-, and 2-string-) inverters in the design of
utility-scale PV power plants, as opposed to a central inverter configuration. The study focuses solely on the effects
of irradiance mismatch (series and parallel), and is based on 24 test case simulations that consider the effects of
system geometry (direct shading at sub-cell resolution, anisotropic diffuse shading and IAM at module level), and
detailed calculation of electrical mismatch losses (using full IV curve solution to include the potential effects of
MPPT voltage limitations). Three inverter configurations are evaluated for six ~1 MWp layout variations at two
distinct locations. The diverse matrix of design conditions is helpful in providing qualitative design guidelines, and in
identifying conditions in which a detailed comparative study ought to be performed.
PV Battery Systems Sizing to Account for the Provision of Ancillary Services under Different Scenarios for Energy Policies and Tariffs
Creators: name: Arrifano Manito, A.R.
name: Novaes Cândido De Souza, K.J.F.
name: Pinho Almeida, M.
name: Figueiredo, G.
name: Zilles, R.
name: Tavares Pinho, J.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Design and Installation of PV Systems

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1946-1952
description: This paper discusses the implications that several aspects, such as cost, types of services to be provided, and policies, may have on the sizing of PV systems with batteries, and presents a framework for decision making on the adoption of such systems, evaluating the profitability and the risks involved. The methodology is based on a sensitivity analysis carried out by simulating several scenarios of electricity prices, system costs, and the possible existence of incentives. The results show that nowadays the viability of PV systems with batteries is still very dependent on a price drop of the battery systems. This makes the adoption of such systems a risky investment, since long payback periods are needed. Moreover, ancillary services such as power factor compensation are only viable to increase the profitability of other services such as energy trade with the grid. If power factor compensation is the sole purpose of the system, the battery would be unnecessary since the storage capacity would be very small, and solutions like capacitor banks would be better suited.
Impact of Dynamic-Mechanical Load on PV Modules Mounted on Single-Axis Tracker
Creators: name: Stellbogen, D.
name: Lechner, P.
name: Schanz, O.
name: Hummel, S.
name: Schnepf, J.
name: Kaiser, M.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Design and Installation of PV Systems

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1909-1913
description: PV modules with crystalline silicon technology in some cases exhibit cells with microcracks which provokes
concerns about the impact of such microcracks on the energy delivery performance as well as the reliability of the
modules. Further, the increasing application of single-axis solar trackers in PV plants raises the question whether this
might cause special performance and reliability challenges due to the increased mechanical stress executed onto the
modules.
In order to access the extend of deflections induced onto the PV modules in such installations and the impact these
deflections might have on the power and energy yield, a field investigation has been conducted at the ZSW test site
Widderstall with complementary laboratory tests. Two PV modules with initial microcracks were monitored mounted
on a single-axis tracker and underwent laboratory pre- and post-characterisation as well as power measurements in
artificial deflection.
The sample modules showed only a moderate STC power loss after one year of operation, which could not certainly
be attributed to the microcracks, and no further power decrease after one and a half years. The module back surface
deflections recorded in the field were almost entirely within a few millimeters. In flash simulator measurements with
artificial deflection, a significant power reduction was observed only at deflections of 5 mm or more to the back. The
combination of these findings with the field observations indicates that energy yield losses induced by deflections
from daily cyclic tracker movements and wind load pressure are not expected.
Automatic Topology Identification for Energy Load Management in Electro Mobility Charging Applications to Increase Share of Local Renewables
Creators: name: Ravanbach, B.
name: Klement, P.
name: Hanke, B.
name: Von Maydell, K.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Grid and Energy System Integration

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1903-1908
description: Existing distribution networks are designed based on certain assumptions. Therefore, standard load profiles and coincidence factors are identified and the power lines are dimensioned with sufficient power reserve. Nowadays, the use cases are changing and will change even more, when sector coupling applications like electro mobility and distributed renewable energy generation systems get into focus to achieve common carbon reduction targets. Then, the power distribution networks can either be strengthened in order to operate the networks with large power reserve or the power applications can be managed in order to achieve higher utilization factors of the distribution networks. In the latter case, detailed information about the distribution network need to be known, for not exceeding any physical limits of the power lines. This detailed information is difficult to maintain and extract from available documentation especially in old or privately operated networks, so that this information needs to be gathered by measurements. An automatic topology identification method has been developed in order to identify the low voltage network topology for distributed loads and sources. The aim of this approach is to get the basic information for a local energy and load management system, which updates topology information under normal operation conditions.
Nanometer-scale Exchange Interactions Between Spin Centers in Diamond
Creators: name: Kortan, V. R.
name: Şahin, C.
name: Flatté, M. E.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Exchange interactions between isolated pairs of spin centers in diamond have been calculated, based on an accurate atomistic electronic structure for diamond and any impurity atoms, for spin-center separations up to 2~nm. The exchange interactions exceed dipolar interactions for spin center separations less than 3~nm. NV$^-$ spin centers, which are extended defects, interact very differently depending on the relative orientations of the symmetry axis of the spin center and the radius vector connecting the pair. Exchange interactions between transition-metal dopants behave similarly to those of NV$^-$ centers. The Mn\---Mn exchange interaction decays with a much longer length scale than the Cr\---Cr and Ni\---Ni exchange interactions, exceeding dipolar interactions for Mn\---Mn separations less than 5~nm. Calculations of these highly anisotropic and spin-center-dependent interactions provide the potential for design of the spin-spin interactions for novel nanomagnetic structures.
description: 5 pages
Advances in blends preparation based on electrically conducting polymer
Creators: name: Bhadra, Jolly
name: Al-Thani, Noora
Publisher: name: Manara - Qatar Research Repository
Year: 2022
Subjects: subject: Environmental engineering
subject: FOS: Environmental engineering

description: This work presents an extensively detailed study on preparation and performance of four different hydrochloric acid–doped polyaniline (PANI) blends. The blends are obtained by changing four different polymers, viz. polyvinyl alcohol (PVA), polystyrene (PS), polyvinyl chloride (PVC), and sodium alginate (SA) keeping PANI concentration constant. Finally, the blend films deposited on substrates are used to characterize the surface, structural morphology, chemical interaction (SEM and FTIR), thermal properties (TGA and DSC), and mechanical properties by tensile testing. The morphological analysis shows uniform chemical blending of PANI with all three insulating matrices except in PVC matrix. FTIR and TGA results also suffice the fact that PANI particle has a chemical interaction with polymer backbones. Electrical conductivity study of PANI blend reveals that PANI-PVA forms the highest conducting blend with the conductivity of order of 10−2 S/cm and PANI-PVC has the lowest at 10−13S/cm.Other Information Published in: Emergent Materials
 License: https://creativecommons.org/licenses/by/4.0
See article on publisher's website: http://dx.doi.org/10.1007/s42247-019-00027-7
The Surplus of Copying: How Shadow Libraries and Pirate Archives Contribute to the Creation of Cultural Memory and the Commons
Creators: name: Sollfrank, Cornelia
Publisher: name: Zenodo
Year: 2019
Subjects: Copyright
Shadow Libraries
Commons
Pirate Libraries

description: Digital artworks tend to have a problematic relationship with the white cube – in particular, when they are intended and optimized for online distribution. While curators and exhibition-makers usually try to avoid showing such works altogether, or at least aim at enhancing their sculptural qualities to make them more presentable, the exhibition Top Tens featured an abundance of web quality digital artworks, thus placing emphasis on the very media condition of such digital artifacts. The exhibition took place at the Onassis Cultural Center in Athens in March 2018 and was part of the larger festival Shadow Libraries: UbuWeb in Athens, an event to introduce the online archive UbuWeb to the Greek audience and discuss related cultural, ethical, technical, and legal issues. This text takes the event – and the exhibition in particular – as a starting point for a closer look at UbuWeb and the role an artistic approach can play in building cultural memory within the neoliberal knowledge economy.
description: + ID: 562159 + Reihentitel: Edition Angewandte
Technical Evaluation of a Stand-Alone PV Heat Pump System for Space Heating/ Cooling Applications without Batteries
Creators: name: Lorenzo, C.
name: Narvarte Fernández, L.
name: Martinez-Moreno, F.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Design and Installation of PV Systems

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1914-1918
description: In the last years, the concept of solar photovoltaic (PV) powered heat pumps (HP) has become very
attractive, in order to match the increasing heating/cooling demand with a renewable and environmentally-friendly
energy source. The objective of this work is to technically validate a stand-alone PV-HP system for space
heating/cooling applications. This paper describes the prototype system installed in Madrid (Spain) for this purpose,
together with the definition of the validation tests to be performed. Finally, some modifications are proposed for the
performance indicators that are traditionally used for comparing HP and PV systems, in order to achieve a
characterization that is more specific to PV-powered systems.
Digital removable partial dentures
Creators: name: Tamimi, Faleh
name: Almufleh, Balqees
name: Caron, Eric
name: Alageel, Omar
Publisher: name: Manara - Qatar Research Repository
Year: 2022
Subjects: subject: Dentistry
subject: FOS: Clinical medicine

description: Recently, digital techniques have revolutionized the production of partial removable dental prostheses (PRDPs). This chapter reviews current systems for PRDP production, how they are done in clinical practice, advantages and limitations, and current literature regarding their clinical performance. Currently, several digital techniques are available in the market for PRDP production including subtractive and additive techniques. Subtractive milling technique is mainly effective for non-metal PRDP, whereas additive techniques are used mainly in metal PRDP. Digital techniques expand the range of materials that can be utilized for PRDP production, including new polymers (PEEK), and facilitate previously difficult procedures such as casting titanium PRDP, which can be produced more easily with digital methods. This review shows that available evidence suggests that these techniques have promising clinical results. Laser sintering resulted in higher patient’s satisfaction compared to conventional PRDP. However, long-term clinical trials are recommended to explore the long-term effects of these techniques. Moreover, this review showed the lack of evidence on the clinical performance of non-metal partial removable dental prostheses.Other Information Published in: Clinical Dentistry Reviewed
 License: https://creativecommons.org/licenses/by/4.0
See article on publisher's website: http://dx.doi.org/10.1007/s41894-020-00074-y
Sur le p-rang du groupe des classes de Q(N^1/p)
Creators: name: Lecouturier, Emmanuel
Publisher: name: arXiv
Year: 2016
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics

description: Let N and p be two prime numbers > 3 such that p divides N-1. We estimate the p-rank of the class group of Q(N^(1/p)) in terms of the discrete logarithm, with values un F_p, of certain units. Using the Gross--Koblitz formula and identities on the N-adic Gamma function, we explicitly compute these logarithms. A special case (for which we don't have an elementary proof) of our formula is the following: assume there are some integers $a$, $b$ such that N = (a^p+b^p)/(a+b). Then (a+b)*\prod_{k=1}^{(N-1)/2} k^{8k} is a p-th power modulo N. Furthermore we give a new proof which doesn't use modular forms of a result of Calegari and Emerton.
Mapping out the Trajectory of Islamic Perspectives on Neuroethics
Creators: name: Noorfuad, Noorina
Publisher: name: Manara - Qatar Research Repository
Year: 2022
Subjects: subject: Policy and administration
subject: Philosophy
subject: FOS: Philosophy, ethics and religion

description: The advancements of medical technology incited multi-disciplinary discussions with regard to its ethical implications. Within the neuroscientific domain, the term ‘neuroethics’ has gained prominence over recent years. However, the contributions of religious perspectives in the nascent field of neuroethics are particularly few. The scarce literature on Islamic perspectives on neuroethics merely questioned its importance and introduced a sharia-based framework that can be implemented. Building upon this, the possible trajectories of Islamic perspectives on neuroethics can be mapped out by tapping into several issues within Islamic bioethics, such as cloning and genomics. Topics such as these are deliberated through the collective discussions by contemporary Muslim scholars and biomedical scientists, thus producing well-informed dialogues and decisions. Building upon these may assist in developing further the Islamic perspectives on issues within neuroethics. This lays the groundwork for all the stakeholders involved in advance, in order to predict and prevent potential harms and challenges.Other Information Published in: Asian Bioethics Review
 License: https://creativecommons.org/licenses/by/4.0
See article on publisher's website: http://dx.doi.org/10.1007/s41649-022-00203-8
Yield Simulations for Horizontal Axis Trackers with Bifacial PV Modules in PVsyst
Creators: name: Mermoud, A.
name: Wittmer, B.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Design and Installation of PV Systems

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1929-1934
description: The simulation of the energy yield of Bifacial PV modules is not straightforward, since most of the light reaching the back side of the PV modules is scattered back from the ground. For tracking systems this is particularly challenging since the geometry is changing as the sun moves through the sky. In PVsyst, a simplified 2D model was introduced to describe bifacial horizontal single axis trackers with regular spacing. The approach uses view factors to model the fraction of light that is scattered back to the back side of the PV modules. The bifacial calculation includes direct and sky diffuse contributions on the back side, as well as ground scattering to the front and back side of the modules.
Luthers kleiner Katechismus lenkt auf einen harten Weg, bis Christus gnädig kommt
Creators: name: Meding, Wichmann Von
Publisher: name: Lutherische Beiträge
Year: 1970

description: Lutherische Beiträge, Bd. 16 Nr. 2 (2011): Lutherische Beiträge, Band 16, Heft 2
Traffic Impact Assessment for the Stadiums Hosting FIFA 2022 World Cup in Qatar: A Case Study
Creators: name: Tahmasseby, Shahram
name: Reddipalayam Palaniappan Subramania, Padmanaban
Publisher: name: Manara - Qatar Research Repository
Year: 2022
Subjects: subject: Civil engineering
subject: FOS: Civil engineering

description: The State of Qatar has made extensive preparation to successfully host the upcoming FIFA 2022 World Cup, a tournament that will be held for the first time in the Middle East and the North Africa region. In preparation for this tournament, a wide-ranging operational strategy is being developed for each of the stadiums separately. This paper looks into the preparation stages of master planning and transport strategy for one of the hosting venues, which is located in Al Rayyan, Qatar. An overview of the Fédération Internationale de Football Association (FIFA) tournament, its assumptions, spatial planning, traffic modeling, Temporary Traffic Management, and the required mitigations from the transport operations perspective alongside the lessons learned are discussed in the paper. Other Information Published in: Iranian Journal of Science and Technology, Transactions of Civil Engineering
 License: https://creativecommons.org/licenses/by/4.0
See article on publisher's website: http://dx.doi.org/10.1007/s40996-021-00723-7
Sizing of Photovoltaic Systems for Self-Consumption in Commercial and Industrial Applications
Creators: name: Roessler, T.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Design and Installation of PV Systems

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1942-1945
description: The integration of photovoltaic (PV) systems with the power supply from the electricity grid (and usually Diesel generators as backup power source) is becoming increasingly popular in commercial and industrial (C&I) applications in developing countries. In the absence of a feed-in tariff scheme and net metering, as is common in such markets, self-consumption of the power generated by the PV system is required. Therefore, its size must be carefully chosen to enable a high PV Utilization, thus ensuring a low effective cost of the PV energy, while reaching the highest possible PV Coverage of the energy demand. The work presented here outlines a methodology to determine an appropriate PV system size in this context. Basic inputs are (1) a so-called “load profile”, i.e., a time series of the power consumption during a representative period of operation, (2) time-resolved information about the power generated by the PV system, and (3) insights about the seasonality of the power consumption. Based on this, the percentage of both, the PV power consumed instantaneously by the loads and the energy demand covered by PV, can be predicted for a given PV system size, allowing an optimization of the latter. Using example data from actual C&I consumers in Ghana, the methodology is demonstrated in practice.
Determining the type of orbits in the central regions of barred galaxies
Creators: name: Zotos, Euaggelos E.
name: Caranicolas, Nicolaos D.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We use a simple dynamical model which consists of a harmonic oscillator and a spherical component, in order to investigate the regular or chaotic character of orbits in a barred galaxy with a central spherically symmetric nucleus. Our aim is to explore how the basic parameters of the galactic system influence the nature of orbits, by computing in each case the percentage of chaotic orbits, as well as the percentages of different types of regular orbits. We also give emphasis to the types of regular orbits that support either the formation of nuclear rings or the barred structure of the galaxy. We provide evidence that the traditional x1 orbital family does not always dominate in barred galaxy models since we found several other types of resonant orbits which can also support the barred structure. We also found that sparse enough nuclei, fast rotating bars and high energy models can support the galactic bars. On the other hand, weak bars, dense central nuclei, slowly rotating bars and low energy models favor the formation of nuclear rings. We also compare our results with previous related work.
description: Published in Research in Astronomy and Astrophysics (RAA) journal
The KdV hierarchy in optics
Creators: name: Horsley, S. A. R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: There is a well explored relationship between quantum mechanical scattering from a potential and the Korteweg-de Vries (KdV) equation of fluid dynamics: if the potential is 'evolved' according to the KdV equation then it will have the same reflectivity and transmissivity as a function of energy, for each snapshot in time. In this work we explore this connection in optics, where the permittivity plays the role of the potential. We begin by deriving the relationship between the Helmholtz equation and the KdV equation in terms of the current induced in a material when a permittivity profile is changed slightly. It is then shown that the KdV equation can be used to design a plethora of bounded complex potentials that are relfectionless from both sides for all angles of incidence, and planar periodic media that exhibit a real Bloch vector for all angles of propagation. Finally we apply the KdV equation to reduce the reflection of a wave from an interface between two media of differing refractive indices.
description: 15 pages, 5 figures
Cyber Security Requirements for Platforms Enhancing AI Reproducibility
Creators: name: Falade, Polra Victor
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cryptography and Security (cs.CR)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Scientific research is increasingly reliant on computational methods, posing challenges for ensuring research reproducibility. This study focuses on the field of artificial intelligence (AI) and introduces a new framework for evaluating AI platforms for reproducibility from a cyber security standpoint to address the security challenges associated with AI research. Using this framework, five popular AI reproducibility platforms; Floydhub, BEAT, Codalab, Kaggle, and OpenML were assessed. The analysis revealed that none of these platforms fully incorporates the necessary cyber security measures essential for robust reproducibility. Kaggle and Codalab, however, performed better in terms of implementing cyber security measures covering aspects like security, privacy, usability, and trust. Consequently, the study provides tailored recommendations for different user scenarios, including individual researchers, small laboratories, and large corporations. It emphasizes the importance of integrating specific cyber security features into AI platforms to address the challenges associated with AI reproducibility, ultimately advancing reproducibility in this field. Moreover, the proposed framework can be applied beyond AI platforms, serving as a versatile tool for evaluating a wide range of systems and applications from a cyber security perspective.
Spatial Verification Using Wavelet Transforms: A Review
Creators: name: Weniger, Michael
name: Kapp, Florian
name: Friederichs, Petra
Publisher: name: arXiv
Year: 2016
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: Due to the emergence of new high resolution numerical weather prediction (NWP) models and the availability of new or more reliable remote sensing data, the importance of efficient spatial verification techniques is growing. Wavelet transforms offer an effective framework to decompose spatial data into separate (and possibly orthogonal) scales and directions. Most wavelet based spatial verification techniques have been developed or refined in the last decade and concentrate on assessing forecast performance (i.e. forecast skill or forecast error) on distinct physical scales. Particularly during the last five years, a significant growth in meteorological applications could be observed. However, a comparison with other scientific fields such as feature detection, image fusion, texture analysis, or facial and biometric recognition, shows that there is still a considerable, currently unused potential to derive useful diagnostic information. In order to tab the full potential of wavelet analysis, we revise the state-of-the art in one- and two-dimensional wavelet analysis and its application with emphasis on spatial verification. We further use a technique developed for texture analysis in the context of high-resolution quantitative precipitation forecasts, which is able to assess structural characteristics of the precipitation fields and allows efficient clustering of ensemble data.
description: Revised Manuscript submitted to Quarterly Journal of the Royal Meteorological Society (10 May 2016)
P2I-NET: Mapping Camera Pose to Image via Adversarial Learning for New View Synthesis in Real Indoor Environments
Creators: name: Kang, Xujie
name: Liu, Kanglin
name: Duan, Jiang
name: Gong, Yuanhao
name: Qiu, Guoping
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Given a new $6DoF$ camera pose in an indoor environment, we study the challenging problem of predicting the view from that pose based on a set of reference RGBD views. Existing explicit or implicit 3D geometry construction methods are computationally expensive while those based on learning have predominantly focused on isolated views of object categories with regular geometric structure. Differing from the traditional \textit{render-inpaint} approach to new view synthesis in the real indoor environment, we propose a conditional generative adversarial neural network (P2I-NET) to directly predict the new view from the given pose. P2I-NET learns the conditional distribution of the images of the environment for establishing the correspondence between the camera pose and its view of the environment, and achieves this through a number of innovative designs in its architecture and training lost function. Two auxiliary discriminator constraints are introduced for enforcing the consistency between the pose of the generated image and that of the corresponding real world image in both the latent feature space and the real world pose space. Additionally a deep convolutional neural network (CNN) is introduced to further reinforce this consistency in the pixel space. We have performed extensive new view synthesis experiments on real indoor datasets. Results show that P2I-NET has superior performance against a number of NeRF based strong baseline models. In particular, we show that P2I-NET is 40 to 100 times faster than these competitor techniques while synthesising similar quality images. Furthermore, we contribute a new publicly available indoor environment dataset containing 22 high resolution RGBD videos where each frame also has accurate camera pose parameters.
Some students plagiarism tricks, and tips for effective check
Creators: name: Elkhatat, Ahmed M.
name: Elsaid, Khaled
name: Almeer, Saeed
Publisher: name: Manara - Qatar Research Repository
Year: 2022
Subjects: subject: Education systems
subject: Sociology
subject: FOS: Sociology

description: One of the main goals of assignments in the academic environment is to assess the students’ knowledge and mastery of a specific topic, and it is crucial to ensure that the work is original and has been solely made by the students to assess their competence acquisition. Therefore, Text-Matching Software Products (TMSPs) are used by academic institutes to ensure academic integrity and address plagiarism. However, some students find ways to trick TMSPS. In this paper, files with the common tricks students do to beat TMSPS have been created and investigates with nine academic level TMPS to evaluate their effectiveness against these tricks, identifying the strengths and weaknesses of each TMSP, and providing instructors with some practical tips on checking plagiarism effectively and spotting any tricks to cheat without getting noticed.Other Information Published in: International Journal for Educational Integrity
 License: https://creativecommons.org/licenses/by/4.0
See article on publisher's website: http://dx.doi.org/10.1007/s40979-021-00082-w
Embedding Dynamical Mean-Field Theory for Superconductivity in Layered Materials and Heterostructures
Creators: name: Petocchi, Francesco
name: Capone, Massimo
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study layered systems and heterostructures of s-wave superconductors by means of a suitable generalization of Dynamical Mean-Field Theory. In order to reduce the computational effort, we consider an embedding scheme in which a relatively small number of active layers is embedded in an effective potential accounting for the effect of the rest of the system. We introduce a feedback of the active layers on the embedding potential that improves on previous approaches and essentially eliminates the effects of the finiteness of the active slab allowing for cheap computation of very large systems. We extend the method to the superconducting state, and we benchmark the approach by means of simple paradigmatic examples showing some examples on how an interface affects the superconducting properties. As examples, we show that superconductivity can penetrate from an intermediate coupling superconductor into a weaker coupling one for around ten layers, and that the first two layers of a system with repulsive interaction can turn superconducting by proximity effects even when charge redistribution is inhibited.
description: 8 pages, 5 figures
Monopole holes in a partially ordered spin liquid
Creators: name: Jaubert, Ludovic D. C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: If spin liquids have been famously defined by what they are not, i.e. ordered, the past years have seen the frontier between order and spin liquid starting to fade, with a growing number of materials whose low-temperature physics cannot be explained without co-existence of (partial) magnetic order and spin fluctuations. Here we study an example of such co-existence in the presence of magnetic dipolar interactions, related to spin ice, where the order is long range and the fluctuations support a Coulomb gauge field. Topological defects are effectively coupled via energetic and entropic Coulomb interactions, the latter one being stronger than for the spin-ice ground state. Depending on whether these defects break the divergence-free condition of the Coulomb gauge field or the long-range order, they are respectively categorized as monopoles - as in spin ice - or monopole holes, in analogy with electron holes in semiconductors. The long-range order plays the role of a fully-occupied valence band, while the Coulomb spin liquid can be seen as an empty conducting band. These results are discussed in the context of other lattices and models which support a similar co-existence of Coulomb gauge field and long-range order. We conclude this work by explaining how dipolar interactions lift the spin liquid degeneracy at very low energy scale by maximizing the number of flippable plaquettes, in light of the equivalent quantum dimer model.
description: invited paper for the special issue on "Quantum Spin Ice and Liquid in Geometrically Frustrated Magnets" edited by Y.-J. Kao, S. Onoda and S. Nakatsuji
Innovative Solar Spectral Beam Splitting Concepts: Alternative Fuels Production
Creators: name: Mittelman, G.
name: Kribus, A.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Grid and Energy System Integration

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1895-1898
description: To date solar hydrogen and other solar fuels production is not competitive with fossil fuels. We present
an analysis of a solar fuels/chemicals production plant based on spectral beam splitting and high temperature
electrolysis. In this system, long wave radiation is reflected to a thermal receiver, while short wave radiation is
transmitted to photovoltaic converters located below the splitter. The combined electricity and high temperature heat
is then utilized to produce alternative fuels/chemicals in a high temperature electrolysis reactor. Significant advantages
of this design include (i) conversion of the infra-red radiation into high grade heat, reducing the reactor power
requirement (ii) reduction in reactor energy losses and (iii) simple design combined with reactor operating well below
1000oC. The resulting solar-to-fuel efficiency is higher than reference figures by 25-60%.
Modelling Control Methods for PV-Based Communal Grids with Different Line Resistances and Impedances
Creators: name: Nixon Opiyo, N.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Grid and Energy System Integration

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1870-1875
description: Different droop control methods for PV-based communal grid networks (minigrids and microgrids) with different line resistances (R) and impedances (X) are modelled and simulated in MATLAB to determine the most efficient control method for a given network. Results show that active power-frequency (P-f) droop control method is the most efficient for low voltage transmission networks with low X/R ratios while reactive power-voltage (Q-V) droop control method is the most efficient for systems with high X/R ratios. For systems with complex line resistances and impedances, i.e. near unity X/R ratios, P-f or Q-V droop methods cannot individually efficiently regulate line voltage and frequency. For such systems, P-Q-f droop control method, where both active and reactive power could be used to control PCC voltage via shunt-connected inverters, is determined to be the most efficient control method. Results also show that shunt-connection of inverters leads to improved power flow control of interconnected communal grids by allowing feeder voltage regulation, load reactive power support, reactive power management between feeders, and improved overall system performance against dynamic disturbances.
The Development and Test of the PV Concentrator System with Electrical and Thermal Output
Creators: name: Okhorzina, A.
name: Yurchenko, A.
name: Tai, D.W.
name: Mekhtiev, A.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Grid and Energy System Integration

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1892-1894
description: The aim of the article is to provide the reader with some information about a design of hybrid system.
Hybrid system represents a concentrator photovoltaic solar energy system with electrical and thermal output. This
system allows more effective using of photovoltaic modules in region with some solar radiance. Low concentrator
adds to a beam solar flow, and cooling system reduces a risk of overheating and premature degradation of
photovoltaic modules. Removing heat will be used on water heating in boiler or heat accumulator.
The computer modeling is applied for design of some system elements. Parameters of coil pipe of cooling system are
developed. The concentrator optimization is providing more uniformly illumination of photovoltaic module surface.