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Integrated multi-objective optimisation of the support structure of heliostats in concentrated solar power plants using a genetic algorithm

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IOP Conference Series: Materials Science and engineering 2022年第1期1214卷

作者： L Lomazzi F Cadini M Giglio C Cancro G Ciniglio G Graditi A Pontecorvo Politecnico di Milano Department of Mechanical Engineering Via La Masa n.1 Milan Italy Italian National Agency for New Technologies Energy and Sustainable Economic Development ENEA – Research Center Piazza E. Fermi 1 80055 Portici (NA) Italy

The optimisation of the support structure of heliostats in concentrating solar power plants is a fundamental task aimed at attempting to reduce the high levelised cost of energy (LCOE) of current configurations. In this work, an integrated multi-objective optimisation framework is presented, which relies on the combination of a lean and fast structural model with a genetic algorithm to simultaneously minimise both the overall mass of the support structure and the mean angle of rotation of the mirror surface, which directly affects the optical efficiency of the component. A particular feature of the proposed framework is that it represents an integrated solution, i.e., it allows to simultaneously optimise the main components of the heliostat support structure, i.e., the pedestal, the truss and the back support structure, assuming they are off-the-shelf components easily available on the market. The optimisation problem is set up selecting as design variables (i) the number of elements in the back support structure and (ii) the relevant characteristics of all the components considered, i.e., section shape and dimensions, according to the components commercial datasheets. At each iteration of the optimisation process, the structural model is fed with the current design variables values and, according to some computed aerodynamic loads, it allows evaluating the displacement and rotation of the points of interest within the mirror surface. An aerodynamic model present in the literature based on experimental wind tunnel tests is used to estimate the wind forces acting on the heliostat as a function both of the mirror inclination angle with respect to the ground and of the wind direction with respect to the mirror orientation. In this work, the proposed methodology is demonstrated on a realistic case study and the results commented in detail, highlighting possible future developments and the limitations of the framework.

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Electrical and optical characterisation of low temperature grown InGaAs for photodiode applications

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SEMICONDUCTOR SCIENCE AND TECHNOLOGY 2020年第9期35卷

作者： Lim, Leh Woon Patil, Pallavi Marko, Igor P. Clarke, Edmund Sweeney, Stephen J. Ng, Jo Shien David, John P. R. Tan, Chee Hing Univ Sheffield Dept Elect & Elect Engn Sheffield S1 4DE S Yorkshire England Univ Sheffield EPSRC Natl Epitaxy Facil Sheffield S3 7HQ S Yorkshire England Univ Surrey Adv Technol Inst Guildford GU2 7XH Surrey England Univ Surrey Dept Phys Guildford GU2 7XH Surrey England

Dilute bismide and nitride alloys are promising semiconductors for bandgap engineering, opening additional design freedom for devices such as infrared photodiodes. Low growth temperatures are required to incorporate bismuth or nitrogen into iii-V semiconductors. However, the effects of low growth temperature on dark current and responsivity are not well understood. In this work, a set of InGaAs p-i-n wafers were grown at a constant temperature of 250, 300, 400 and 500 degrees C for all p, i and n layers. A second set of wafers was grown where the p and n layers were grown at 500 degrees C while the i-layers were grown at 250, 300 and 400 degrees C. Photodiodes were fabricated from all seven wafers. When constant growth temperature was employed (for all p, i and n layers), we observed that photodiodes grown at 500 degrees C show dark current density at -1 V that is six orders of magnitude lower while the responsivity at an illumination wavelength of 1520 nm is 4.5 times higher than those from photodiodes grown at 250 degrees C. Results from the second set of wafers suggest that performance degradation can be recovered by growing the p and n layers at high temperature. For instance, comparing photodiodes with i-layers grown at 250 degrees C, photodiodes showed dark current density at -1 V that is five orders of magnitude lower when the p and n layers were grown at 500 degrees C. Postgrowth annealing, at 595 degrees C for 15 min, on the two wafers grown at 250 and 300 degrees C showed recovery of diode responsivity but no significant improvement in the dark current. Our work suggests that growth of the cap layer at high temperature is necessary to maintain the responsivity and minimise the dark current degradation, offering a pathway to developing novel photodiode materials that necessitate low growth temperatures. The data reported in this paper is available from the ORDA digital repository.

关键词： indium gallium arsenide photodiodes low temperature molecular beam epitaxy growth

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Novel design strategy for GaAs-based solar cell by application of single-walled carbon nanotubes topmost layer

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ENERGY SCIENCE & engineering 2020年第8期8卷 2938-2945页

作者： Mitin, Dmitry M. Bolshakov, Alexey D. Neplokh, Vladimir Mozharov, Alexey M. Raudik, Sergei A. Fedorov, Vladimir V. Shugurov, Konstantin Yu. Mikhailovskii, Vladimir Yu. Rajanna, Pramod M. Fedorov, Fedor S. Nasibulin, Albert G. Mukhin, Ivan S. St Petersburg Acad Univ 8 KhlopinaBld 3A St Petersburg 194021 Russia Peter Great St Petersburg Polytech Univ St Petersburg Russia St Petersburg State Univ St Petersburg Russia Skolkovo Inst Sci & Technol Moscow Russia Aalto Univ Espoo Finland ITMO Univ St Petersburg Russia

Attempts to improve solar cells efficiency touch all its constituents and are directly related to their fabrication protocols. While the most promising material platform for high efficiency photovoltaic devices is still iii-V semiconductors, introduction of novel materials like single-walled carbon nanotubes (SWCNTs), which are characterized by unique combination of conductivity and transparency, might greatly yield the device performance. Here, for the first time, we present the results of the fabrication and characterization of a thin-film GaAs solar cell with a SWCNT top contact. We examine the contact between the SWCNT film and the semiconductor structure by means of the optical and electron beam-induced current techniques. The fabricated device demonstrates better performance, that is, increased power conversion efficiency from 10.6% to 11.5% when compared to the cell with the traditional metal contact grid, stemming from the enhanced photocurrent collection efficiency and low parasitic light absorption in the emitter layer. We envision future prospects to exploit the multifunctionality of the SWCNTs in fabrication of highly efficient photovoltaic devices including flexible solar cells.

关键词： EBIC EQE GaAs OBIC solar cell SWCNT

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Using effective medium theories to design tailored nanocomposite materials for optical systems 19

Using effective medium theories to design tailored nanocompo...

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19th Conference on current developments in Lens design and optical engineering

作者： Werdehausen, Daniel Staude, Isabelle Burger, Sven Petschulat, Joerg Scharf, Toralf Pertsch, Thomas Decker, Manuel Carl Zeiss Corp Res & Technol Carl Zeiss Promenade 10 D-07745 Jena Germany Friedrich Schiller Univ Jena Abbe Ctr Photon Inst Appl Phys Albert Einstein Str 15 D-07745 Jena Germany Ecole Polytech Fed Lausanne Nanophoton & Metrol Lab CH-1015 Lausanne Switzerland JCMwave GmbH Bolivaralle 22 D-14050 Berlin Germany Zuse Inst Berlin Takustr 7 D-14195 Berlin Germany Carl Zeiss SMT GmbH Semicond Mask Solut Carl Zeiss Promenade 10 D-07745 Jena Germany Fraunhofer Inst Appl Opt & Precis Engn Albert Einstein Str 7 D-07745 Jena Germany

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

Modern optical systems are subject to very restrictive performance, size and cost requirements. Especially in portable systems size often is the most important factor, which necessitates elaborate designs to achieve the desired specifications. However, current designs already operate very close to the physical limits and further progress is difficult to achieve by changing only the complexity of the design. Another way of improving the performance is to tailor the optical properties of materials specifically to the application at hand. A class of novel, customizable materials that enables the tailoring of the optical properties, and promises to overcome many of the intrinsic disadvantages of polymers, are nanocomposites. However, despite considerable past research efforts, these types of materials are largely underutilized in optical systems. To shed light into this issue we, in this paper, discuss how nanocomposites can be modeled using effective medium theories. In the second part, we then investigate the fundamental requirements that have to be fulfilled to make nanocomposites suitable for optical applications, and show that it is indeed possible to fabricate such a material using existing methods. Furthermore, we show how nanocomposites can be used to tailor the refractive index and dispersion properties towards specific applications.

关键词： Nanocomposites Nanomaterials optical materials optical design optical Systems Dispersion engineering Effective medium theory Mie theory

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design of ergonomic handpieces for a CO₂ laser system for surgical and cosmetological applications 19

Design of ergonomic handpieces for a CO<sub>2</sub> laser sy...

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19th Conference on current developments in Lens design and optical engineering

作者： Zavatskaia, Kseniia Voznesenskaya, Anna ITMO Univ Dept Appl & Comp Opt St Petersburg Russia

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

The CO2 laser systems are widely used for different specialised surgery types and cosmetological procedures. The market is filled with various offers regarding the systems, however, every manufacturer supplies a very limited range of handpieces with the equipment. Thus, the work of surgeon or a medical worker is complicated by the discrepancy of a handpiece with the ergonomic/ technical requirements for a specific procedure. It may result in negative consequences of the procedure itself or a choice not in favor of laser technologies. The work presents the design of optical system and construction of specialised handpieces for CO2 laser system based on the discussion with medical workers of several hospitals that directly interact with the equipment and the technical requirements of medical procedures.

关键词： CO2 laser handpiece laser surgery optical design

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Caustic surfaces produced by a plane wavefront refracted through cemented doublet lenses 19

Caustic surfaces produced by a plane wavefront refracted thr...

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19th Conference on current developments in Lens design and optical engineering

作者： Avendano-Alejo, Maximino Carmen Lopez-Bautista, M. Castaneda, Luis Univ Nacl Autonoma Mexico Inst Ciencias Aplicadas & Tecnol Apdo Postal 70-186 Mexico City 04510 DF Mexico Inst Politecn Nacl Escuela Super Med Plan San Luis & Diaz Mirson S-N Mexico City 11340 DF Mexico

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

We study the formation of caustic surfaces produced by cemented doublet lenses, considering a plane wavefront propagating parallel to the optical axis and neglecting the refractive index of the optical cement between two simple lenses which are in contact. We have already seen that the shape of caustic surfaces can represent the monochromatic aberrations that we call image errors;furthermore the shape of the caustic can be modified by changing the parameters of design for two conic lenses in contact, in such a way that if we are able to vanish the caustic, the optical system produces either an image without spherical aberration or longitudinal chromatic aberration reduced, commonly known as spherochromatism. The shape of the caustic surface is a function of the indices of refraction involved in the process of refraction, and all the parameters of two simple lenses. We provide an analytic equation for the caustic surfaces in a meridional plane and an example is presented.

关键词： Caustic Surfaces Cemented doublet lenses optical design Principal Surfaces

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Band structure engineering and defect control of oxides for energy applications

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Chinese Physics B 2018年第11期27卷 112-119页

作者： Hui-Xiong Deng Jun-Wei Luo Su-Huai Wei State Key Laboratory of Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China University of Chinese Academy of Sciences Beijing 100049 China Beijing Computational Science Research Center Beijing 100193 China

Metal oxides play an essential role in modern optoelectronic devices because they have many unique physical properties such as structure diversity, superb stability in solution, good catalytic activity, and simultaneous high electron conductivity and optical transmission. Therefore, they are widely used in energy-related optoelectronic applications such as photovoltaics and photoelectrochemical（PEC） fuel generation. In this review, we mainly discuss the structure engineering and defect control of oxides for energy applications, especially for transparent conducting oxides（TCOs） and oxide catalysts used for water splitting. We will review our current understanding with an emphasis on the contributions of our previous theoretical modeling, primarily based on density functional theory. In particular, we highlight our previous work：（i） the fundamental principles governing the crystal structures and the electrical and optical behaviors of TCOs;（ii） band structures and defect properties for n-type TCOs;（iii） why p-type TCOs are difficult to achieve;（iv） how to modify the band structure to achieve p-type TCOs or even bipolarly dopable TCOs;（v） the origin of the high-performance of amorphous TCOs; and（vi） band structure engineering of bulk and nano oxides for PEC water splitting. Based on the understanding above, we hope to clarify the key issues and the challenges facing the rational design of novel oxides and propose new and feasible strategies or models to improve the performance of existing oxides or design new oxides that are critical for the development of next-generation energy-related applications.

关键词： band-structure engineering defect control oxides density functional theory

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Key Challenges and Results in the design of Cubesat Laser Terminals, optical Heads and Coarse Pointing Assemblies

Key Challenges and Results in the Design of Cubesat Laser Te...

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International Conference on Space optical Systems and Applications (ICSOS)

作者： M. Dresscher C. W. Korevaar N. C. J. van der Valk T. J. de Lange R. Saathof N. Doelman W. E. Crowcombe C. M. Duque H. de Man J. D. Human G. Witvoet N. van der Heiden R. den Breeje S. Kuiper E. C. Fritz TNO Technical Sciences Delft Netherlands

The anticipated capacity benefit of optical satellite communications has triggered a cascade of technology developments. In this paper, we present three such technologies, namely; i). A cube satellite laser terminal (CubeCAT), ii). A lower Earth orbit satellite optical head (LEOCAT) and iii). A calibration and verification test bench for coarse pointing assemblies, named pointing test bench (PTB). For these technologies, pointing stability and accuracy are central challenges. For i) and ii), we discuss anticipated effects of the thermal and mechanical disturbances that threaten the optical alignment of the system. We furthermore explain the mitigation of these effects through the system design so that a high optical performance can be maintained. For iii), we discuss the mechanical design challenges, in combination with modelling and calibration procedures for the system. Effective dealing with the three of them in turn enables highly accurate mirror orientation and rotation. design specifications and current status are presented for each system.

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optical design and Predicted Performance of the WFIRST Phase-B Imaging Optics Assembly and Wide Field Instrument 19

Optical Design and Predicted Performance of the WFIRST Phase...

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19th Conference on current developments in Lens design and optical engineering

作者： Pasquale, Bert A. Casey, Thomas Marx, Catherine Gao, Guangjun Armani, Nerses Content, David Hagopian, John Jurling, Alden Jackson, Clifton Liu, Alice Whipple, Art Murray, Jacob NASA Goddard Space Flight Ctr Greenbelt MD 20771 USA AS&D Inc 7000 Muirkirk Meadows Dr Beltsville MD 20705 USA Sigma Space Inc 4600 Forbes Blvd Lanham MD 20706 USA SGT Inc 7701 Greenbelt Rd Greenbelt MD 20770 USA ATA Aerosp Inc Greenbelt MD 20770 USA Conceptual Analyt Inc Glenn Dale MD 20769 USA Rose Hulman Inst Technol Terre Haute IN 47803 USA

ISBN: (数字)9781510620629

ISBN: (纸本)9781510620629

Now in Phase-B, the architecture of the Wide-Field Infra-Red Survey Telescope (WFIRST) payload has matured since 2013 to accommodate various opto-mechanical constraints. Based on a 2.4-meter aperture Forward optical Assembly (FOA), the Imaging Optics Assembly (IOA) provides corrected optical fields to each on-board instrument. Using a Three Mirror Anastigmat (TMA) optical design, the Wide-Field Channel (WFC) provides similar to 1/3-square degree of instantaneous field coverage at 0.11 arcsecond pixel scale. The WFC as-built predictive analysis anticipates near diffraction-limited imaging over a focal plane of 300.8 million pixels, operating in seven panchromatic bands between 0.48 -2.0 mu m, or a 1-octive multi-spectral imaging mode from similar to 0.95-1.93 mu m. The IOA provides the Coronagraph Instrument (CGI) a collimated beam with very specific wavefront constraints. We present configuration changes since 2013 that improved interfaces, improved testability, and reduced technical risk. We provide an overview of our Integrated Modeling results, performed at an unprecedented level for a phase-A study, to illustrate performance margins with respect to static wavefront error, jitter, and thermal drift.

关键词： Space Instrumentation Astronomical Optics Imaging Systems Telescopes Dark Energy Spectroscopy Systems engineering Integrated Modeling

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Mechanical design of the optical modules intended for IceCube-Gen2

arXiv

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arXiv 2023年

作者： Makino, Yuya Abbasi, R. Ackermann, M. Adams, J. Agarwalla, S.K. Aguilar, J.A. Ahlers, M. Alameddine, J.M. Amin, N.M. Andeen, K. Anton, G. Argüelles, C. Ashida, Y. Athanasiadou, S. Audehm, J. Axani, S.N. Bai, X. Balagopal, A.V. Baricevic, M. Barwick, S.W. Basu, V. Bay, R. Becker Tjus, J. Beise, J. Bellenghi, C. Benning, C. BenZvi, S. Berley, D. Bernardini, E. Besson, D.Z. Bishop, A. Blaufuss, E. Blot, S. Bohmer, M. Bontempo, F. Book, J.Y. Borowka, J. Boscolo Meneguolo, C. Böser, S. Botner, O. Böttcher, J. Bouma, S. Bourbeau, E. Braun, J. Brinson, B. Brostean-Kaiser, J. Burley, R.T. Busse, R.S. Butterfield, D. Campana, M.A. Carloni, K. Carnie-Bronca, E.G. Cataldo, M. Chattopadhyay, S. Chau, N. Chen, C. Chen, Z. Chirkin, D. Choi, S. Clark, B.A. Clark, R. Classen, L. Coleman, A. Collin, G.H. Conrad, J.M. Cowen, D.F. Dasgupta, B. Dave, P. Deaconu, C. De Clercq, C. De Kockere, S. DeLaunay, J.J. Delgado, D. Deng, S. Deoskar, K. Desai, A. Desiati, P. de Vries, K.D. de Wasseige, G. DeYoung, T. Diaz, A. Díaz-Vélez, J.C. Dittmer, M. Domi, A. Dujmovic, H. DuVernois, M.A. Ehrhardt, T. Eller, P. Ellinger, E. El Mentawi, S. Elsässer, D. Engel, R. Erpenbeck, H. Evans, J. Evans, J.J. Evenson, P.A. Fan, K.L. Fang, K. Farrag, K. Farrag, K. Fazely, A.R. Fedynitch, A. Feigl, N. Fiedlschuster, S. Finley, C. Fischer, L. Flaggs, B. Fox, D. Franckowiak, A. Fritz, A. Fujii, T. Fürst, P. Gallagher, J. Ganster, E. Garcia, A. Gerhardt, L. Gernhaeuser, R. Ghadimi, A. Giri, P. Glaser, C. Glauch, T. Glüsenkamp, T. Goehlke, N. Goswami, S. Grant, D. Gray, S.J. Gries, O. Griffin, S. Griswold, S. Guevel, D. Günther, C. Gutjahr, P. Haack, C. Haji Azim, T. Hallgren, A. Halliday, R. Hallmann, S. Halve, L. Halzen, F. Hamdaoui, H. Ha Minh, M. Hanson, K. Hardin, J. Harnisch, A.A. Hatch, P. Haugen, J. Haungs, A. Heinen, D. Helbing, K. Hellrung, J. Hendricks, B. Henningsen, F. Henrichs, J. Heuermann, L. Heyer, N. Hickford, S. Hidvegi, A. Dept. of Physics Wisconsin IceCube Particle Astrophysics Center University of Wisconsin-Madison MadisonWI53706 United States III. Physikalisches Institut RWTH Aachen University AachenD-52056 Germany Department of Physics University of Adelaide Adelaide5005 Australia Dept. of Physics and Astronomy University of Alaska Anchorage 3211 Providence Dr. AnchorageAK99508 United States Dept. of Physics University of Texas at Arlington Science Hall 502 Yates St. Rm 108 Box 19059 ArlingtonTX76019 United States CTSPS Clark-Atlanta University AtlantaGA30314 United States School of Physics Center for Relativistic Astrophysics Georgia Institute of Technology AtlantaGA30332 United States Dept. of Physics Southern University Baton RougeLA70813 United States Dept. of Physics University of California BerkeleyCA94720 United States Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Institut für Physik Humboldt-Universität zu Berlin BerlinD-12489 Germany Fakultät für Physik & Astronomie Ruhr-Universität Bochum BochumD-44780 Germany Université Libre de Bruxelles Science Faculty CP230 BrusselsB-1050 Belgium Dienst ELEM BrusselsB-1050 Belgium Department of Physics Laboratory for Particle Physics and Cosmology Harvard University CambridgeMA02138 United States Dept. of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Dept. of Physics The International Center for Hadron Astrophysics Chiba University Chiba263-8522 Japan Department of Physics Loyola University Chicago ChicagoIL60660 United States Dept. of Astronomy and Astrophysics University of Chicago ChicagoIL60637 United States Dept. of Physics University of Chicago ChicagoIL60637 United States Enrico Fermi Institute University of Chicago ChicagoIL60637 United States Kavli Institute for Cosmological Physics University of Chicago ChicagoIL60637 United States Dept. of Physics and Astronomy University of Canterbury Private Bag 4800 C

IceCube-Gen2 is an expansion of the IceCube neutrino observatory at the South Pole that aims to increase the sensitivity to high-energy neutrinos by an order of magnitude. To this end, about 10,000 new optical modules will be installed, instrumenting a fiducial volume of about 8 km3. Two newly developed optical module types increase IceCube's current sensitivity per module by a factor of three by integrating 16 and 18 newly developed four-inch PMTs in specially designed 12.5-inch diameter pressure vessels. Both designs use conical silicone gel pads to optically couple the PMTs to the pressure vessel to increase photon collection efficiency. The outside portion of gel pads are pre-cast onto each PMT prior to integration, while the interiors are filled and cast after the PMT assemblies are installed in the pressure vessel via a pushing mechanism. This paper presents both the mechanical design, as well as the performance of prototype modules at high pressure (70 MPa) and low temperature (-40 ◦C), characteristic of the environment inside the South Pole ice. Copyright © 2023, The Authors. All rights reserved.

关键词： Silicones

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