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Stathatos E, Tzimas E, Benardos P, Vosniakos GC. Convolutional Neural Networks for Raw Signal Classification in CNC Turning Process Monitoring. Sensors (Basel) 2024; 24:1390. [PMID: 38474926 DOI: 10.3390/s24051390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/19/2024] [Accepted: 02/19/2024] [Indexed: 03/14/2024]
Abstract
This study addresses the need for advanced machine learning-based process monitoring in smart manufacturing. A methodology is developed for near-real-time part quality prediction based on process-related data obtained from a CNC turning center. Instead of the manual feature extraction methods typically employed in signal processing, a novel one-dimensional convolutional architecture allows the trained model to autonomously extract pertinent features directly from the raw signals. Several signal channels are utilized, including vibrations, motor speeds, and motor torques. Three quality indicators-average roughness, peak-to-valley roughness, and diameter deviation-are monitored using a single model, resulting in a compact and efficient classifier. Training data are obtained via a small number of experiments designed to induce variability in the quality metrics by varying feed, cutting speed, and depth of cut. A sliding window technique augments the dataset and allows the model to seamlessly operate over the entire process. This is further facilitated by the model's ability to distinguish between cutting and non-cutting phases. The base model is evaluated via k-fold cross validation and achieves average F1 scores above 0.97 for all outputs. Consistent performance is exhibited by additional instances trained under various combinations of design parameters, validating the robustness of the proposed methodology.
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Affiliation(s)
- Emmanuel Stathatos
- Manufacturing Technology Laboratory, School of Mechanical Engineering, National Technical University of Athens, Heroon Polytechniou 9, GR15772 Athens, Greece
| | - Evangelos Tzimas
- Manufacturing Technology Laboratory, School of Mechanical Engineering, National Technical University of Athens, Heroon Polytechniou 9, GR15772 Athens, Greece
| | - Panorios Benardos
- Manufacturing Technology Laboratory, School of Mechanical Engineering, National Technical University of Athens, Heroon Polytechniou 9, GR15772 Athens, Greece
| | - George-Christopher Vosniakos
- Manufacturing Technology Laboratory, School of Mechanical Engineering, National Technical University of Athens, Heroon Polytechniou 9, GR15772 Athens, Greece
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Chalkias DA, Mourtzikou A, Katsagounos G, Kalarakis AN, Stathatos E. Development of Greener and Stable Inkjet-Printable Perovskite Precursor Inks for All-Printed Annealing-Free Perovskite Solar Mini-Modules Manufacturing. Small Methods 2023; 7:e2300664. [PMID: 37381687 DOI: 10.1002/smtd.202300664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Indexed: 06/30/2023]
Abstract
Inkjet-printing is considered an emerging manufacturing process for developing perovskite solar cells (PSCs) with low material wastes and high production throughput. Up-to-now, all case studies on inkjet-printed PSCs are based on the exploitation of toxic solvents and/or high-molarity perovskite precursor inks that are known to enable the development of high-efficiency photovoltaics (PVs). The present study provides a new insight for developing lower-toxicity, high performance and stable (for more than 2 months) inkjet-printable perovskite precursor inks for fully ambient air processed PSCs. Using an ink composed of a green low vapor pressure noncoordinating solvent and only 0.8 m of perovskite precursors, the feasibility of fabricating high-quality and with minimum coffee-ring defects, annealing-free perovskite absorbent layers under ambient atmosphere is demonstrated. Noteworthily, the PSCs fabricated using the industry-compatible carbon-based hole transport material free architecture and the proposed ink present an efficiency >13% that is considered on the performance records for the under-consideration PV architecture employing an inkjet-printed active layer. Outstanding is also found the stability of the devices under the conditions determined by the ISOS-D-1 protocol (T95 = 1000 h). Finally, the perspective of upscaling PSCs to the mini-module level (100 cm2 aperture area) is demonstrated, with the upscaling losses to be as low as 8.3%rel dec-1 per upscaled active area.
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Affiliation(s)
- D A Chalkias
- BRITE Solar Technologies, Rio-Patras, GR26504, Greece
- Nanotechnology & Advanced Materials Laboratory, Department of Electrical and Computer Engineering, University of the Peloponnese, Patras, GR26334, Greece
| | - A Mourtzikou
- BRITE Solar Technologies, Rio-Patras, GR26504, Greece
| | - G Katsagounos
- BRITE Solar Technologies, Rio-Patras, GR26504, Greece
| | - A N Kalarakis
- Department of Mechanical Engineering, University of the Peloponnese, Patras, GR26334, Greece
| | - E Stathatos
- BRITE Solar Technologies, Rio-Patras, GR26504, Greece
- Nanotechnology & Advanced Materials Laboratory, Department of Electrical and Computer Engineering, University of the Peloponnese, Patras, GR26334, Greece
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Dake DV, Raskar ND, Mane VA, Sonpir RB, Stathatos E, Vasundhara M, Meena R, Asokan K, Dole BN. Intriguing physicochemical properties and impact of co-dopants on N-doped graphene oxide based ZnS nanowires for photocatalytic application. Sci Rep 2023; 13:7595. [PMID: 37164980 PMCID: PMC10172323 DOI: 10.1038/s41598-023-33453-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 04/13/2023] [Indexed: 05/12/2023] Open
Abstract
Superparamagnetic N-doped graphene oxide (GO)- with ZnS nanowires was synthesized by a one-step hydrothermal method by doping dilute amounts of Ga, Cr, In, and Al ions for water treatment and biomedical applications. In these experiments, to enhance their properties, 2% of Ga3+, In3+, and or Al3+ were codoped along with 2% Cr ions in these ZnS nanowires. The nanocomposite with the composition, In0.02Cr0.02Zn0.96S, has better photocatalytic efficiency than other co-doped nanocomposites. The In (metalloids) and Cr (transition metal ion) are the best combinations to increase the magnetic properties which are beneficial for photocatalytic activity. Synthesized nanocomposite materials were characterized by several techniques such as X-ray diffraction, Field emission-scanning electron microscope (FESEM) with EDAX, vibrating sample magnetometer (VSM), UV-Vis, X-ray photoelectron spectroscopy (XPS), and fluorescence spectroscopy. The correlation of intriguing magnetic properties with their photocatalytic properties is also discussed. XPS was employed for the detection of surface defects, phase transformation, and the nature of chemical components present in the nanocomposites. The Frankel and substitutional defects have a direct impact on photocatalytic activity that was determined from the fluorescence (FL) spectroscopy. FL and XPS reveal that the Cr and In codoped composite has a higher percentage of defects hence its photocatalytic efficiency reaches 94.21%.
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Affiliation(s)
- D V Dake
- Advanced Materials Research Laboratory, Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, 431004, M.S., India
| | - N D Raskar
- Advanced Materials Research Laboratory, Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, 431004, M.S., India
| | - V A Mane
- Advanced Materials Research Laboratory, Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, 431004, M.S., India
| | - R B Sonpir
- Advanced Materials Research Laboratory, Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, 431004, M.S., India
| | - E Stathatos
- Electrical and Computer Engineering Department, Nanotechnology and Advanced Materials Laboratory, University of the Peloponnese, 26334, Patras, Greece
| | - M Vasundhara
- Polymer and Functional Department, CSIR-Indian Institution of Chemical Technology, Tarnaka, Hyderabad, Telangana, 500007, India
| | - R Meena
- Materials Science, Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi, 110 067, India
| | - K Asokan
- Department of Physics and Centre for Interdisciplinary Research, University of Petroleum and Energy Studies (UPES), Dehradun, Uttarakhand, 248007, India
| | - B N Dole
- Advanced Materials Research Laboratory, Department of Physics, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad, 431004, M.S., India.
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Chalkias D, Karavioti A, Papanicolaou G, Stathatos E. Stability assessment of carbon-based hole-transport-layer-free perovskite solar cells under accelerated ageing: A combined experimental and predictive modelling analysis. Electrochim Acta 2022. [DOI: 10.1016/j.electacta.2022.140905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Mavrikos A, Papoulis D, Todorova N, Papailias I, Trapalis C, Panagiotaras D, Chalkias D, Stathatos E, Gianni E, Somalakidi K, Sygkridou D, Komarneni S. Synthesis of Zn/Cu metal ion modified natural palygorskite clay – TiO2 nanocomposites for the photocatalytic outdoor and indoor air purification. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113568] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Christoforidis KC, Melchionna M, Montini T, Papoulis D, Stathatos E, Zafeiratos S, Kordouli E, Fornasiero P. Solar and visible light photocatalytic enhancement of halloysite nanotubes/g-C3N4 heteroarchitectures. RSC Adv 2016. [DOI: 10.1039/c6ra15581b] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The charged surface of HNTs allows efficient charge separation and increased pollutant adsorption, enhancing the overall photocatalytic performance of the HNTs/g-C3N4 heteroarchitectures.
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Affiliation(s)
- K. C. Christoforidis
- Department of Chemical and Pharmaceutical Sciences
- ICCOM-CNR Trieste Research Unit and INSTM Research Unit
- University of Trieste
- 34127 Trieste
- Italy
| | - M. Melchionna
- Department of Chemical and Pharmaceutical Sciences
- ICCOM-CNR Trieste Research Unit and INSTM Research Unit
- University of Trieste
- 34127 Trieste
- Italy
| | - T. Montini
- Department of Chemical and Pharmaceutical Sciences
- ICCOM-CNR Trieste Research Unit and INSTM Research Unit
- University of Trieste
- 34127 Trieste
- Italy
| | - D. Papoulis
- Department of Geology
- University of Patras
- 26504 Patras
- Greece
| | - E. Stathatos
- Department of Electrical Engineering
- Technological Educational Institute (TEI) of Western Greece
- 26334 Patras
- Greece
| | - S. Zafeiratos
- Institut de Chimie et Procédés Pour l'Energie
- l'Environnement et la Santé
- (ICPEES) ECPM
- University of Strasbourg
- 67087 Strasbourg
| | - E. Kordouli
- Department of Chemistry
- University of Patras
- 26504 Patras
- Greece
| | - P. Fornasiero
- Department of Chemical and Pharmaceutical Sciences
- ICCOM-CNR Trieste Research Unit and INSTM Research Unit
- University of Trieste
- 34127 Trieste
- Italy
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Sygkridou D, Sahin C, Varlikli C, Stathatos E. Comparative studies of pyridine and bipyridine ruthenium dye complexes with different side groups as sensitizers in sol-gel quasi-solid-state dye sensitized solar cells. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.01.195] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sygkridou D, Rapsomanikis A, Stathatos E. Quasi-Solid State Dye-Sensitized Solar Cells with Photoanodes Prepared by Different TiO 2 Precursors Using Sol–Gel Method. ACTA ACUST UNITED AC 2014. [DOI: 10.1166/jsim.2014.1063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Antoniadou M, Siranidi E, Vaenas N, Kontos AG, Stathatos E, Falaras P. Photovoltaic Performance and Stability of CH 3NH 3PbI 3–xCl x Perovskites. ACTA ACUST UNITED AC 2014. [DOI: 10.1166/jsim.2014.1060] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Rapsomanikis A, Apostolopoulou A, Stathatos E, Lianos P. Cerium-modified TiO2 nanocrystalline films for visible light photocatalytic activity. J Photochem Photobiol A Chem 2014. [DOI: 10.1016/j.jphotochem.2014.02.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Dori M, Seintis K, Stathatos E, Tsigaridas G, Lin TY, Lin J, Fakis M, Giannetas V, Persephonis P. Electron injection studies in TiO2 nanocrystalline films sensitized with fluorene dyes and photovoltaic characterization. The effect of co-adsorption of a bile acid derivative. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.01.049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Fakis M, Dori M, Stathatos E, Chou HH, Yen YS, Lin JT, Giannetas V, Persephonis P. Electron injection in TiO2 films and quasi-solid state solar cells sensitized with a dipolar fluorene organic dye. J Photochem Photobiol A Chem 2013. [DOI: 10.1016/j.jphotochem.2012.10.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Stathatos E, Papoulis D, Aggelopoulos CA, Panagiotaras D, Nikolopoulou A. TiO2/palygorskite composite nanocrystalline films prepared by surfactant templating route: synergistic effect to the photocatalytic degradation of an azo-dye in water. J Hazard Mater 2012; 211-212:68-76. [PMID: 22177018 DOI: 10.1016/j.jhazmat.2011.11.055] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 10/28/2011] [Accepted: 11/16/2011] [Indexed: 05/31/2023]
Abstract
Microfibrous palygorskite clay mineral and nanocrystalline TiO(2) are incorporating in the preparation of nanocomposite films on glass substrates via sol-gel route at 500°C. The synthesis involves a simple chemical method employing nonionic surfactant molecule as pore directing agent along with the acetic acid-based sol-gel route without direct addition of water molecules. Drying and thermal treatment of composite films lead to the elimination of organic material while ensure the formation of TiO(2) nanoparticles homogeneously distributed on the surface of the palygorskite microfibers. TiO(2) nanocomposite films without cracks consisted of small crystallites in size (12-16 nm) and anatase crystal phase was found to cover palygorskite microfibers. The composite films were characterized by microscopy techniques, UV-vis, IR spectroscopy, and porosimetry methods in order to examine their structural properties. Palygorskite/TiO(2) composite films with variable quantities of palygorskite (0-2 w/w ratio) were tested as new photocatalysts in the photo-discoloration of Basic Blue 41 azo-dye in water. These nanocomposite films proved to be very promising photocatalysts and highly effective to dye's discoloration in spite of the small amount of immobilized palygorskite/TiO(2) catalyst onto glass substrates. 3:2 palygorskite/TiO(2) weight ratio was finally the most efficient photocatalyst while reproducible discoloration results of the dye were obtained after three cycles with same catalyst. It was also found that palygorskite showed a positive synergistic effect to the TiO(2) photocatalysis.
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Affiliation(s)
- E Stathatos
- Electrical Engineering Department, Technological-Educational Institute of Patras, GR-26334 Patras, Greece.
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Gallos L, Stathatos E, Lianos P, Argyrakis P. Photophysical behavior of a homologous series of amphiphilic hemicyanine dyes in thin AOT films. Chem Phys 2002. [DOI: 10.1016/s0301-0104(01)00525-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Stathatos E, Lianos P, Rakotoaly RH, Laschewsky A, Zana R. Photophysical Behavior of a New Gemini Surfactant in Neat Solvents and in Micellar Environments. J Colloid Interface Sci 2000; 227:476-481. [PMID: 10873336 DOI: 10.1006/jcis.2000.6903] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel fluorescent gemini surfactant, 1,4-bis-(2'-(N-dodecyl pyridinio-4"-yl)ethenyl)benzene dibromide, abbreviated BDPEBB, has been synthesized and its photophysical properties have been studied in different environments. BDPEBB has a limited solubility in alcohols where it is found in aggregate form at concentrations>/=1 mM. In other solvents, e.g., water, it is only found in aggregate form, even at much lower concentrations. Solvent polarity has a small and insignificant solvatochromic effect but alcohols give a specific interaction with BDPEBB, causing a significant hypsochromic shift in absorption maxima and a large increase in relative fluorescence efficiency. Pyrene fluorescence is effectively quenched by BDPEBB. Pyrene also forms associative complexes with BDPEBB in water. These complexes are partly dissociated in the presence of surfactant micelles. Triton X-100 micelles provide a favorable environment for BDPEBB solubilization well distinguished from the behavior of ionic surfactants. Small quantities of BDPEBB have a large influence on the behavior of aqueous sodium dodecylsulfate (SDS) and sodium decylsulfate (SDeS) micelles, inducing the formation of large aggregates, visible by the naked eye. These large aggregates are most probably microcrystals of BDPEBB(2+)/2DS(-) or BDPEBB(2+)/2DeS(-). The aggregation number of SDS and SDeS micelles in the absence and in the presence of BDPEBB has been calculated by exploitation of the static luminescence quenching kinetics of Ru(bpy)(3)(2+) by 9-methylanthracene, both solubilized in the micellar phase. It has been observed that Ru(bpy)(3)(2+) inhibits the precipitation of SDeS micelles in the presence of BDPEBB. Our results suggest that double-chain surfactant chromophores should be employed with particular care if they are to be used as probes of the micellar phase. Copyright 2000 Academic Press.
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Affiliation(s)
- E Stathatos
- Engineering Science Department, University of Patras, Patras, 26500, Greece
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Stathatos E, Tsiourvas D, Lianos P. Titanium dioxide films made from reverse micelles and their use for the photocatalytic degradation of adsorbed dyes. Colloids Surf A Physicochem Eng Asp 1999. [DOI: 10.1016/s0927-7757(98)00292-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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