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KUROIWA, Masamitsu, Yuhei MATSUBARA, Yukihiko HASEGAWA, Yasushi ICHIMURA, Ken YOSHIZU, Tomoyoshi KOIZUMI, Masami SANNO et Naotsugu YAMAMOTO. « 3D Morphodynamic Model for Sandy Beach with Shore Reef ». Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 67, no 2 (2011) : I_531—I_535. http://dx.doi.org/10.2208/kaigan.67.i_531.
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Brounstein, Zachary, Jarrod Ronquillo et Andrea Labouriau. « 3D Printed Chromophoric Sensors ». Chemosensors 9, no 11 (9 novembre 2021) : 317. http://dx.doi.org/10.3390/chemosensors9110317.
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Eight chromophoric indicators are incorporated into Sylgard 184 to develop sensors that are fabricated either by traditional methods such as casting or by more advanced manufacturing techniques such as 3D printing. The sensors exhibit specific color changes when exposed to acidic species, basic species, or elevated temperatures. Additionally, material properties are investigated to assess the chemical structure, Shore A Hardness, and thermal stability. Comparisons between the casted and 3D printed sensors show that the sensing devices fabricated with the advanced manufacturing technique are more efficient because the color changes are more easily detected.
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Felices, Niño B., et Bryan B. Pajarito. « Effect of Silane-Treated Wollastonite on Mechanical and Thermal Properties of 3D-Printed ABS via Fused Deposition Modeling ». Key Engineering Materials 877 (février 2021) : 61–66. http://dx.doi.org/10.4028/www.scientific.net/kem.877.61.
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The effect of the addition of epoxysilane-treated wollastonite (ETW) to the mechanical and thermal properties of 3D-printed acrylonitrile butadiene styrene (ABS) via fused deposition modeling (FDM) was investigated. The loading of ETW was varied at 1, 3, and 5wt%. The 3D-printed composites were evaluated by scanning electron microscopy (SEM) tensile test, shore D hardness, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The addition of ETW increases the tensile strength, elastic modulus, and toughness of ABS by up to 46.6, 56.2, and 53.7 %, respectively. The shore D hardness increases with increasing ETW. Morphological analysis show that this improvement in mechanical properties is a result of the high aspect ratio of the fillers, the uniform dispersion of ETW in the ABS matrix, and the orientation of ETW particles toward the direction of tensile stress. The glass transition temperature (Tg) of the composites increases and the onset of degradation slightly shifted to higher temperature with an increase in filler loading. The addition of ETW to ABS matrix in FDM 3D printing improved the mechanical and thermal properties of ABS.
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Canning, John, Caspar Clark, Monica Dayao, Daniel de LaMela, Michael Logozzo et Jing Zhao. « Anti-Reflection Coatings on 3D-Printed Components ». Coatings 11, no 12 (10 décembre 2021) : 1519. http://dx.doi.org/10.3390/coatings11121519.
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The use of anti-reflection coatings on 3D-printed components to reduce both Fresnel reflections and scattering is explored. Two similar photo-initiated acrylic commercial material structures, known as Standard Clear (SC: T~60% @ λ = 800 nm) and VeroClear (VC: T~90% @ λ = 800 nm), used specifically for optical components, are examined. The refractive indices for slab samples~(5 × 5 × 0.7) cm are measured at λ = 650 nm and averaged over the slab area: n(SC)~(1.49 ± 0.04) and n(VC)~(1.42 ± 0.03). Within experimental error, novel Shore D mapping is used to show hardness distribution across the surface flats, with VC slightly harder than SC, where VC = 85.9 ± 0.3 and SC = 84.4 ± 1.3, indicating uniform hardness. A TiO2/MgF2 anti-reflection twin-layer coating is deposited onto one side of an unpolished SC slab and binds well, passing standard peeling and humidity tests. Shore hardness increases to SCCOATED = 87.5 ± 1.5. It is found to reduce the measured Fresnel reflection and surface scatter by~65% without requiring major polishing, paving the way for lower-cost high-quality optics. The demonstration of successful anti-reflection coatings will benefit all 3D-printed component finishes, permitting viable film deposition more broadly.
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Sokolov, Andrei, et Boris Chubarenko. « Numerical simulation of dynamics of sediments disposed in the marine coastal zone of the south-eastern Baltic ». Baltica 31, no 1 (15 juin 2018) : 13–23. http://dx.doi.org/10.5200/baltica.2018.31.02.
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Three dumping sites located at the south-eastern part of the Baltic Sea at shallow depths near the shore of the Sambian Peninsula are considered. The first and second ones are located south and north of the Vistula Lagoon inlet, and are used now for disposing dredged material extracted from the Kaliningrad Seaway Canal. The third dumping site is located near the northern shore of the Sambian Peninsula, east of Cape Gvardeyskiy and assigned for disposing the dredged material extracted from the fairway to the Pionerskiy Port located nearby. All three dumping sites are located either in front of or not far from the eroded segments of the shore. The question behind the study is: Is it possible that disposed material is naturally transported from the damping site to the shore and accumulates there to protect it from erosion? A numerical hydrodynamic transport 3D model (MIKE) was used to model sediment transport under different wind actions. The winds with the speed stronger than 15 m/s wash out disposed material completely from the dumping site and spread it over a wide area with a negligible layer thickness. Winds of about 7–10 m/s transport material along the shore at a distance of a few kilometres; that may be useful for shore protection. Winds with a speed of about 5 m/sec or less do not lead to resuspension of sediments. The first location of the dumping site looks very ineffective for potential protection of the shore nearby. On the other hand, the second and especially the third locations are favourable for the transport of disposed material to the shore; the most favourable conditions are at onshore or alongshore currents.
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Zhang, Jingxin, Dongfang Liang et Hua Liu. « An efficient 3D non-hydrostatic model for simulating near-shore breaking waves ». Ocean Engineering 140 (août 2017) : 19–28. http://dx.doi.org/10.1016/j.oceaneng.2017.05.009.
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Fauzhan Warsito, Indhika, René Machts, Stefan Griebel, Patrique Fiedler et Jens Haueisen. « Influence of silver/silver chloride electroless plating on the Shore hardness of polyurethane substrates for dry EEG electrodes ». Current Directions in Biomedical Engineering 7, no 2 (1 octobre 2021) : 9–12. http://dx.doi.org/10.1515/cdbme-2021-2003.
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Abstract Dry electrodes enable a shorter preparation time for infant EEG. Since infant skin is more sensitive than adult skin, soft electrodes are required to reduce the mechanical stress for this sensitive skin. Thus, soft electrodes are crucial for eventual repetitive and long-term use like in neonatal intensive care units. A biocompatible polyurethane (PU) can be produced in low hardness resulting in a soft and flexible electrode substrate. Silver/silver chloride (Ag/AgCl) electroless plating provides a conductive, electrochemically stable coating but the process may alter the mechanical properties of the electrode substrate. In this study, we assess the hardness of PU material before and after Ag/AgCl plating. The test sample design for Shore hardness measurement is based on ISO 7619-1:2010. Sample production consists of a 3D print master model, silicone molding, PU casting, and finally electroless plating. UPX 8400-1 (Sika AG, Switzerland) is used for the sample substrates. Test samples are produced with 7 different Shore hardness (range A40-A95) and 14 samples (each hardness: 1 uncoated and 1 coated). The hardness measurements are carried out with a lever-operated test stand Shore hardness tester model with a digital hardness tester (TI-AC with HDA 100-1, KERN &SOHN GmbH, Germany).. It is shown that there is a hardness increase (Shore A) due to Ag/AgCl coating with a grand average of 1.1±0.7 (p<0.05). The largest increase of 2.1±0.2 is seen on the initial lowest Shore hardness sample (Shore hardness: 43.4±0.1). The absolute increase of hardness due to the Ag/AgCl coating decreases with increasing substrate hardness. It is concluded that there is no strong hardness increase of PU substrates due to Ag/AgCl plating. Therefore, the material is suitable as a soft electrode for repetitive and long-term use in infant applications.
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Luna, Carlos B. B., Danilo D. Siqueira, Edcleide M. Araújo et Renate M. R. Wellen. « Annealing efficacy on PLA. Insights on mechanical, thermomechanical and crystallinity characters ». MOMENTO, no 62 (1 janvier 2021) : 1–17. http://dx.doi.org/10.15446/mo.n62.89099.
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Poly (lactic acid) (PLA) is widely used biodegradable thermoplastic in the additive manufacturing, mainly on manufactured products through 3D printing. However, PLA is highly fragile and presents low impact strength; hence improvements on this way are industrially and technologically important. Aiming to develop proper methodology for higher PLA performance, this work investigated the effects of thermal annealing on the mechanical properties (impact, tensile, Shore D hardness), heat deflection temperature (HDT), Vicat softening temperature (VST) and crystallinity (X-ray diffraction) of PLA. Injected specimens were annealed in greenhouses at 70, 80, 90 and 100 °C. Annealing at 70 °C was not effective, without verified significant changes. On the other hand, annealing at 80, 90 and 100 °C provided crystalline peaks in DRX, indicating development of structural organization. Expressive results were achieved, at 90 °C, for impact strength, HDT, VST, Shore D hardness and tensile strength, related to non-annealed PLA. Provided results in this work have scientific and technological importance, since the mechanical and thermomechanical properties of PLA were improved using a simple methodology which may render higher performance products mainly for the 3D printing industry of PLA.
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Hsieh, Fan-Chun, Chien-Yao Huang et Yen-Pei Lu. « Wettability and Surface Roughness of Parylene C on Three-Dimensional-Printed Photopolymers ». Materials 15, no 12 (11 juin 2022) : 4159. http://dx.doi.org/10.3390/ma15124159.
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The use of poly-(para-chloro-xylylene) (Parylene C) in microelectromechanical systems and medical devices has increased rapidly. However, little research has been conducted on the wettability and surface roughness of Parylene C after being soaked in solutions. In this study, the contact angle and surface roughness (arithmetic average of roughness) of Parylene C on three-dimensional (3D)-printed photopolymer in 10% sodium hydroxide, 10% ammonium hydroxide, and 100% phosphate-buffered saline (PBS) solutions were investigated using a commercial contact angle measurement system and laser confocal microscope, respectively. The collected data indicated that 10% ammonium hydroxide had no major effect on the contact angle of Parylene C on a substrate, with a Shore A hardness of 50. However, 10% sodium hydroxide, 10% ammonium hydroxide, and 100% PBS considerably affected the contact angle of Parylene C on a substrate with a Shore A hardness of 85. Substrates with Parylene C coating exhibited lower surface roughness than uncoated substrates. The substrates coated with Parylene C that were soaked in 10% ammonium hydroxide exhibited high surface roughness. The aforementioned results indicate that 3D-printed photopolymers coated with Parylene C can offer potential benefits when used in biocompatible devices.
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Sikora, Piotr, Adam Gnatowski et Rafał Gołębski. « Tests of mechanical properties of semicrystalline and amorphous polymeric materials produced by 3D printing ». MATEC Web of Conferences 254 (2019) : 06003. http://dx.doi.org/10.1051/matecconf/201925406003.
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The article presents the results of tests of physical properties of samples from semi-crystalline and amorphous polymeric materials produced using 3D printing. Samples were produced using 3D printing technology on the SIGNAL -ATMAT printer. The following polymeric materials were used to make the samples: TPU thermoplastic polyurethane elastomer, ABS acrylonitrile-butadiene-styrene copolymer, Laywood, PET ethylene terephthalate, PLA poly (lactic acid). The materials were tested for their mechanical properties. The hardness was determined by the Shore method and the ball-pressing method. The tensile strength also was determined. The research samples were subjected to visual analysis on a Keyence microscope to analyze the breakthrough site.
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Passchier, Sandra, Kenneth Rijsdijk et Cees Laban. « Introduction ». Netherlands Journal of Geosciences 84, no 2 (juillet 2005) : 59. http://dx.doi.org/10.1017/s0016774600022952.
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Coastal low-lands are densely populated areas characterized by large economic activity. The shallow subsurface plays an important role because of geotechnical requirements for the foundation of structures and its potential for natural resources, such as sand, gravel, and groundwater. The application of geo-scientific data requires that the subsurface is represented as 2D and 3D models displaying the stratigraphie relations of sedimentary rock units, both on-and off-shore.
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Molina Villamil, Andrés. « Gestión de integridad en facilidades "On Shore" con tecnología "high definition survey" (HDS) 3D ». Ingeniería Solidaria 13, no 23 (1 septembre 2017) : 56–76. http://dx.doi.org/10.16925/in.v23i13.2005.
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Introducción: este artículo es producto de la investigación “Gestión de integridad en facilidades on shore con tecnología high definition survey (hds) 3D” de la Universidad Pedagógica y Tecnológica y de Colombia, realizada durante el 2016 y el 2017. Metodología: se partió de una revisión documental de ScienceDirect, Proquest, ebsco, dialnet, se establecieron los factores generales de un sgi; se presenta la validación de hds3d, la integración al sistema de gestión de integridad y beneficios. Resultados: se presenta una metodología de integración de la tecnología que se basa en un modelamiento láser del estado real en fases “as-built” o “as-it” de los activos para poder tener una visión más real del estado, presentando el estudio de caso de la metodología usada por Inspectra srl (Bolivia). Conclusión: a pesar del poco uso de esta tecnología en facilidades se puede evidenciar la capacidad de generar resultados de integridad como apoyo en ingeniería a la inversa, inspecciones en servicio, aptitud para el servicio y como herramienta de control del manejo del cambio (moc), entre otros, y así poder sobre esto tomar decisiones de cómo gestionarlos usando datos de ubicación y dimensiones reales.
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Protsenko, S. V. « Simulation of wave impact on shore protection structures using 3D model of wave processes ». Journal of Physics : Conference Series 1479 (mars 2020) : 012078. http://dx.doi.org/10.1088/1742-6596/1479/1/012078.
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Tomasicchio, Giuseppe Roberto, Elvira Armenio, Felice D'Alessandro, Nuno Fonseca, Spyros A. Mavrakos, Valery Penchev, Holger Schuttrumpf, Spyridon Voutsinas, Jens Kirkegaard et Palle M. Jensen. « DESIGN OF A 3D PHYSICAL AND NUMERICAL EXPERIMENT ON FLOATING OFF-SHORE WIND TURBINES ». Coastal Engineering Proceedings 1, no 33 (14 décembre 2012) : 67. http://dx.doi.org/10.9753/icce.v33.structures.67.
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The knowledge of the behavior of floating offshore wind turbines (W/T) under wave and/or wind action remains one of the most difficult challenges in offshore engineering which is mostly due to the highly non-linear response of the structure. The present study describes the design process of a 3D physical experiment to investigate the behavior of the most promising structure technology of floating W/T: spar buoy (SB) and tension leg platform (TLP) under different meteo conditions. In order to properly design the two W/T models, the following topics have been analyzed: mooring lines, mass distribution, appropriate scaling factor and data relative to the geometrical characteristics, wave basin dimensions and wind and waves conditions. In addition, the Smoothed Particle Hydrodynamics method (SPH) (Monaghan 1994) has been considered to simulate the 3D behavior of a floating offshore W/T. In particular, the SPH, calibrated and verified on the basis of the experimental observations, may represent a reliable tool for preliminary test of changes in the floater geometry.
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Tzeng, Jy-Jiunn, Tzu-Sen Yang, Wei-Fang Lee, Hsuan Chen et Hung-Ming Chang. « Mechanical Properties and Biocompatibility of Urethane Acrylate-Based 3D-Printed Denture Base Resin ». Polymers 13, no 5 (8 mars 2021) : 822. http://dx.doi.org/10.3390/polym13050822.
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In this study, five urethane acrylates (UAs), namely aliphatic urethane hexa-acrylate (87A), aromatic urethane hexa-acrylate (88A), aliphatic UA (588), aliphatic urethane triacrylate diluted in 15% HDD (594), and high-functional aliphatic UA (5812), were selected to formulate five UA-based photopolymer resins for digital light processing (DLP)-based 3D printing. Each UA (40 wt%) was added and blended homogenously with ethoxylated pentaerythritol tetraacrylate (40 wt%), isobornyl acrylate (12 wt%), diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (3 wt%), and a pink acrylic (5 wt%). Each UA-based resin specimen was designed using CAD software and fabricated using a DLP 3D printer to specific dimensions. Characteristics, mechanical properties, and cytotoxicity levels of these designed UA-based resins were investigated and compared with a commercial 3D printing denture base acrylic resin (BB base) control group at different UV exposure times. Shore hardness-measurement data and MTT assays were analyzed using a one-way analysis of variance with Bonferroni’s post hoc test, whereas viscosity, maximum strength, and modulus were analyzed using the Kruskal–Wallis test (α = 0.05). UA-based photopolymer resins with tunable mechanical properties were successfully prepared by replacing the UA materials and the UV exposure times. After 15 min of UV exposure, the 5812 and 594 groups exhibited higher viscosities, whereas the 88A and 87A groups exhibited lower viscosities compared with the BB base group. Maximum flexural strength, flexural modulus, and Shore hardness values also revealed significant differences among materials (p < 0.001). Based on MTT assay results, the UA-based photopolymer resins were nontoxic. In the present study, mechanical properties of the designed photopolymer resins could be adjusted by changing the UA or UV exposure time, suggesting that aliphatic urethane acrylate has good potential for use in the design of printable resins for DLP-type 3D printing in dental applications.
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Kováčová, Mária, Anna Vykydalová et Zdenko Špitálský. « Polycaprolactone with Glass Beads for 3D Printing Filaments ». Processes 11, no 2 (28 janvier 2023) : 395. http://dx.doi.org/10.3390/pr11020395.
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At present, 3D printing is experiencing a great boom. The demand for new materials for 3D printing is also related to its expansion. This paper deals with manufacturing innovative polymer composite filaments suitable for the Fused Filament Fabrication method in 3D printing. As a filler, common and uncostly glass beads were used and mixed with biocompatible and biodegradable poly (ε-caprolactone), as a polymer matrix. This material was characterized via several physical-chemical methods. The Youngs modulus was increasing by about 30% with 20% loading of glass beads, and simultaneously, brittleness and elongations were decreased. The glass beads do not affect the shore hardness of filaments. The rheological measurement confirmed the material stability in a range of temperatures 75–120 °C. The presented work aimed to prepare lightweight biocompatible, cheap material with appropriate mechanical properties, lower printing temperature, and good printing processing. We can assess that the goal was fully met, and these filaments could be used for a wide range of applications.
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Fateri, Miranda, João Falcão Carneiro, Constantin Schuler, João Bravo Pinto, Fernando Gomes de Almeida, Udo Grabmeier, Tobias Walcher et Michael Salinas. « Impact of 3D Printing Technique and TPE Material on the Endurance of Pneumatic Linear Peristaltic Actuators ». Micromachines 13, no 3 (28 février 2022) : 392. http://dx.doi.org/10.3390/mi13030392.
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In this paper, additive manufacturing was used in order to produce hose prototypes for peristaltic linear pneumatic actuators. In order to optimise the endurance of the actuator, we 3D printed different thermoplastic polyurethane elastomers with different shore hardness levels using ARBURG Plastic Freeforming technology. Furthermore, effects of the hose geometries on the lifetime of the actuator were investigated. Experimental evidence showed that the lifetime of the actuator was dependent on the combination of the hose design and on the material used to manufacture the hose. Moreover, experimental tests showed that the use of the Aurburg-Freeformer 3D printing technology led to a much higher hose endurance than the one reported by using the fused layer manufacturing technique.
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Dong, Yuwen, Iftikhar Satti et Xu Chen. « Microfacies and Reservoir Connectivity of Shore Sandbar, Southern Indus Basin, Pakistan ». Water 14, no 10 (18 mai 2022) : 1614. http://dx.doi.org/10.3390/w14101614.
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Shore sand bar reservoirs have attracted much attention as one of the target intervals with the greatest potential for petroleum exploration and development in marine sedimentary basins. Nevertheless, due to lack of effective research methods, it is difficult to analyze the rapid lateral change and heterogeneity in a sand bar reservoir, which has a major impact on the efficient petroleum development that seriously restricts the rolling evaluation and efficient development of sand-bar reservoirs. In this study, based on integrated analysis of cores, thin sections, logging, 3D seismic data, production test and dynamic data, through a combination analysis of drilling and seismic interpretation data—the petromineral composition, microfacies and reservoir connectivity of the shore sand bar in the southern Indus basin are investigated, which is used for the fine description of the sandbar reservoir. The results show that the shore sand bar is located in a relatively high-energy shore sedimentary environment, which is conducive to forming a favorable lithologic reservoir. Four sedimentary microfacies types are identified, including center bar, bar edge, inter bar and local mudstone interbeds. The sandbar microfacies are changed rapidly, and different microfacies types overlap each other, especially the inter bar and local mudstone interbeds that overlap and intersect in the center bar and bar edge, which significantly reduces the internal reservoir connectivity as well as intensifying the heterogeneity of the sandbar reservoir. The sandbar reservoir is not connected transversely, the physical properties are changing rapidly, and the sandbar reservoir is cut into several relatively independent oil reservoirs.
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Zarkogiannis, Stergios D., Vincent Fernandez, Mervyn Greaves, P. Graham Mortyn, George Kontakiotis et Assimina Antonarakou. « X-ray tomographic data of planktonic foraminifera species Globigerina bulloides from the Eastern Tropical Atlantic across Termination II ». Gigabyte 2020 (25 septembre 2020) : 1–10. http://dx.doi.org/10.46471/gigabyte.5.
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Increased planktonic foraminifera shell weights were recorded during the course of Termination II at a tropical site off the shore of the Mauritanian coast. In order to investigate these increased shell mass values, a series of physicochemical analyses were performed, including X-ray computed tomography (CT). The data are given here. Furthermore, the relevant CT setup, scanning, reconstruction, and visualization methods are explained and the acquired datasets are given, together with 3D volumes and models of the scanned specimens.
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Hsueh, Ming-Hsien, Chao-Jung Lai, Kuan-Yin Liu, Cheng-Feng Chung, Shi-Hao Wang, Chieh-Yu Pan, Wen-Chen Huang, Chia-Hsin Hsieh et Yu-Shan Zeng. « Effects of Printing Temperature and Filling Percentage on the Mechanical Behavior of Fused Deposition Molding Technology Components for 3D Printing ». Polymers 13, no 17 (29 août 2021) : 2910. http://dx.doi.org/10.3390/polym13172910.
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Additive manufacturing (AM) has the advantages of providing materials with lightweight microporous structures and customized features, and being environmentally safe. It is widely used in medical sciences, the aerospace industry, biological research, engineering applications, and other fields. Among the many additive manufacturing methods, fused deposition modeling (FDM) is relatively low-cost, wastes less raw material and has a lower technical threshold. This paper presents a study on 3D printing based on FDM by changing two printing parameters, namely the printing temperature and filling percentage. The produced polylactic acid (PLA) material was analyzed through tensile and Shore D hardness tests and the differences in mechanical properties before and after the UV curing process were analyzed. The results show that increasing the filling percentage or increasing the printing temperature can effectively improve the tensile Young’s modulus, ultimate tensile strength, elongation, and Shore hardness of the material. The UV curing process could enhance the rigidity and hardness of the material significantly but reduced the strength and toughness of the material. These findings could benefit researchers studying FDM with the goal of achieving sustainable manufactured materials.
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Lee, Yun, Jin-Keun Kim, Hyun-Cheol Seol, Joo-Kyoung Yang et Ki-Jung Kim. « 3D numerical analysis of column shortening and shore safety under construction of high-rise building ». Engineering Structures 150 (novembre 2017) : 242–55. http://dx.doi.org/10.1016/j.engstruct.2017.07.049.
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Flores, NatashaY, Frank P. L. Collas et Rob S. E. W. Leuven. « 3D upstream passability of novel river training structures by migratory fish in the river Waal ». Knowledge & ; Management of Aquatic Ecosystems, no 423 (2022) : 22. http://dx.doi.org/10.1051/kmae/2022019.
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Longitudinal training dams (LTDs) are novel river training structures that divide a river into a main navigation channel and protected shore channels. High velocities at the inflows of shore channels constructed in the river Waal (The Netherlands) pose a potential bottleneck for migratory fish species swimming upstream. This study assessed the passability of the inflows using flow velocity datasets from governmental monitoring campaigns collected with an ADCP during high river discharges (Q = 3489–5066 m3/s at Lobith monitoring station). The swimming performance of several migratory fish species were estimated from their total lengths (TLs). A new 3D approach to visualize the flow velocity data using Voxler® software is presented. Gasterosteus aculeatus aculeatus was the only fish species with an adult life stage unable to pass the 9 cases tested due to its small size. The juvenile European eel and thicklip grey mullet passed 1 and 0 of the cases, respectively. The most upstream inflow, located in the inner bend of the river, was the most passable. We recommend maximizing the cross-sectional area of the inflow sills in order to reduce the flow velocities experienced by migrating fish during high river discharges. This approach may be useful to assess passability at other locations and training structures.
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Tian, Li, Jianmin Zheng, Nadia Magnenat Thalmann, Hanhui Li, Qifa Wang, Jialin Tao et Yiyu Cai. « Design of a Single-Material Complex Structure Anthropomorphic Robotic Hand ». Micromachines 12, no 9 (18 septembre 2021) : 1124. http://dx.doi.org/10.3390/mi12091124.
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In the field of robotic hand design, soft body and anthropomorphic design are two trends with a promising future. Designing soft body anthropomorphic robotic hands with human-like grasping ability, but with a simple and reliable structure, is a challenge that still has not been not fully solved. In this paper, we present an anatomically correct robotic hand 3D model that aims to realize the human hand’s functionality using a single type of 3D-printable material. Our robotic hand 3D model is combined with bones, ligaments, tendons, pulley systems, and tissue. We also describe the fabrication method to rapidly produce our robotic hand in 3D printing, wherein all parts are made by elastic 50 A (shore durometer) resin. In the experimental section, we show that our robotic hand has a similar motion range to a human hand with substantial grasping strength and compare it with the latest other designs of anthropomorphic robotic hands. Our new design greatly reduces the fabrication cost and assembly time. Compared with other robotic hand designs, we think our robotic hand may induce a new approach to the design and production of robotic hands as well as other related mechanical structures.
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Blossier, Brice, Christophe Brière, J. A. Roelvink et D. J. R. Walstra. « CHARACTERIZATION OF PROCESSES INVOLVED IN THE RESET OF A SUBTIDAL BAR ». Coastal Engineering Proceedings 1, no 33 (15 décembre 2012) : 101. http://dx.doi.org/10.9753/icce.v33.sediment.101.
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Sand beach profiles can exhibit nearshore sandbars with complex 3D patterns. Under energetic conditions, these patterns disappear and the bars get to a certain extent alongshore uniform. This phenomenon is called a reset. The existing literature mainly concerns the development of the bar patterns (3D) or the cross-shore migration of sandbars (2D). Studies on reset-events from a three dimensional point of view are limited but can be found for instance in Reniers et al. (2004) and Smit (2010). This paper describes an analysis that is aimed at determining the relevant processes involved in the reset of three dimensional subtidal bars and at describing the relative influence of each of these processes. To perform this study, data collected during the ECORS campaign at Le Truc Vert (France) in 2008 are analyzed. In addition, a numerical approach is performed using a research Delft3D model forced by the Xbeach wave generator to investigate the processes involved in a reset-event. The effects of the hydrodynamic external conditions on the flow patterns in the surfzone are investigated. Then the reset is studied in details in order to understand the role of the different processes taken into account by the numerical model. The incident wave energy controls the intensity of the reset. The bar cross-shore migration is controlled by the wave breaking process. The wave breaking position and the dissipation rate of the roller energy controls the generation of Shoreward Propagating Accretionary Waves (SPAW). The straightening of the subtidal bar occurs when the conditions induce a significant longshore current in the surfzone.
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Kranjčević, Lado, Luka Grbčić, Matija Mrazović et Siniša Družeta. « Rijeka Bay 3D VOF Costal Flow Model ». Journal of Maritime & ; Transportation Science 3, no 3 (juin 2020) : 125–32. http://dx.doi.org/10.18048/2020.00.09.
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3D multiphase flow was analyzed in the area of Rijeka bay in the Adriatic Sea. The necessary morphology data in the range of interest of the coastal bottom area were collected and the spatial surface was created. The functionality of the 3D model was studied in the large area of the realistic stochastic structure of the bottom and the shore. The probability of meteorological conditions and wind impact in the model has been shown. The obtained results give a detailed view of the velocity fields in the horizontal plane of different depths. Numerical simulation was performed in open source program OpenFOAM with Volume of Fluid (VOF) method using the Eulerian approach. For solving this problem interFOAM solver for two incompressible, isothermal, immiscible fluids was used. The resulting simulations showed dominant flow from the western coast of the Krk island to the eastern coast of the Istrian peninsula. Seawater enters the bay through the Srednja Vrata and Tihi Kanal and exits the bay through the Vela Vrata. This research has shown that using a VOF method can be successfully implemented for describing fluid motion in large areas such as bays and oceans.
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Qiu, Yinguo, Yaqin Jiao, Juhua Luo, Zhenyu Tan, Linsheng Huang, Jinling Zhao, Qitao Xiao et Hongtao Duan. « A Rapid Water Region Reconstruction Scheme in 3D Watershed Scene Generated by UAV Oblique Photography ». Remote Sensing 15, no 5 (22 février 2023) : 1211. http://dx.doi.org/10.3390/rs15051211.
Texte intégralRésumé :
Oblique photography technology based on UAV (unmanned aerial vehicle) provides an effective means for the rapid, real-scene 3D reconstruction of geographical objects on a watershed scale. However, existing research cannot achieve the automatic and high-precision reconstruction of water regions due to the sensitivity of water surface patterns to wind and waves, reflections of objects on the shore, etc. To solve this problem, a novel rapid reconstruction scheme for water regions in 3D models of oblique photography is proposed in this paper. It extracts the boundaries of water regions firstly using a designed eight-neighborhood traversal algorithm, and then reconstructs the triangulated irregular network (TIN) of water regions. Afterwards, the corresponding texture images of water regions are intelligently selected and processed using a designed method based on coordinate matching, image stitching and clipping. Finally, the processed texture images are mapped to the obtained TIN, and the real information about water regions can be reconstructed, visualized and integrated into the original real-scene 3D environment. Experimental results have shown that the proposed scheme can rapidly and accurately reconstruct water regions in 3D models of oblique photography. The outcome of this work can refine the current technical system of 3D modeling by UAV oblique photography and expand its application in the construction of twin watershed, twin city, etc.
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Appusamy, Anandha Moorthy, Natarajan Nanjappan, Prakash Eswaran et Madheswaran Subramanian. « The effect of natural Gongura roselle fiber on the mechanical properties of 3D printed ABS and PLA composites ». Polimery 67, no 3 (18 mars 2022) : 119–24. http://dx.doi.org/10.14314/polimery.2022.3.4.
Texte intégralRésumé :
The influence of the natural Gongura roselle fiber on the tensile and flexural properties as well as on Shore D hardness of acrylonitrile-butadiene-styrene (ABS) and poly (lactic acid) (PLA) was investigated. The composites were printed in fused deposition modeling (FDM) 3D technique. The addition of natural fiber improved the mechanical properties of the tested composites, while the flexural strength, modulus and hardness were better in the case of ABS-based composite. Whereas, PLA-based composites showed higher tensile strength. The influence of the nozzle angle on the mechanical properties of the composites was also investigated. The best results have been obtained when using an angle of 0 °.
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Arias-Ferreiro, Goretti, Aurora Lasagabáster-Latorre, Ana Ares-Pernas, Pablo Ligero, Sandra María García-Garabal, María Sonia Dopico-García et María-José Abad. « Lignin as a High-Value Bioaditive in 3D-DLP Printable Acrylic Resins and Polyaniline Conductive Composite ». Polymers 14, no 19 (4 octobre 2022) : 4164. http://dx.doi.org/10.3390/polym14194164.
Texte intégralRésumé :
With increasing environmental awareness, lignin will play a key role in the transition from the traditional materials industry towards sustainability and Industry 4.0, boosting the development of functional eco-friendly composites for future electronic devices. In this work, a detailed study of the effect of unmodified lignin on 3D printed light-curable acrylic composites was performed up to 4 wt.%. Lignin ratios below 3 wt.% could be easily and reproducibly printed on a digital light processing (DLP) printer, maintaining the flexibility and thermal stability of the pristine resin. These low lignin contents lead to 3D printed composites with smoother surfaces, improved hardness (Shore A increase ~5%), and higher wettability (contact angles decrease ~19.5%). Finally, 1 wt.% lignin was added into 3D printed acrylic resins containing 5 wt.% p-toluensulfonic doped polyaniline (pTSA-PANI). The lignin/pTSA-PANI/acrylic composite showed a clear improvement in the dispersion of the conductive filler, reducing the average surface roughness (Ra) by 61% and increasing the electrical conductivity by an order of magnitude (up to 10−6 S cm−1) compared to lignin free PANI composites. Thus, incorporating organosolv lignin from wood industry wastes as raw material into 3D printed photocurable resins represents a simple, low-cost potential application for the design of novel high-valued, bio-based products.
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Escobar Guachambala, Miguel Ángel, Javier José Gavilanes Carrión Gavilanes Carrión et Mesías Heriberto Freire Quintanilla. « Evaluación de la capacidad de absorción de energía de impacto y dureza en probetas impresas en 3D de PLA y ABS con estructura cúbica y tri hexagonal ». ConcienciaDigital 3, no 2 (14 avril 2020) : 17–33. http://dx.doi.org/10.33262/concienciadigital.v3i2.1204.
Texte intégralRésumé :
En la actualidad se construyen ortesis personalizadas para rehabilitación física mediante prototipado rápido 3D, debido a esto es de importancia conocer su resistencia mecánica, por esto se plantea ensayar probetas impresas en 3D con filamentos de PLA y ABS. Las probetas de estudio se diseñaron mediante software CAD, en función de la norma ASTM D256; después se imprimieron en 3D con estructura de relleno cúbica y tri hexagonal en materiales de PLA y ABS. Para el análisis de resistencia de las probetas se desarrolló varios ensayos: el ensayo de impacto con péndulo tipo Izod, microscopia de la superficie de rotura y el análisis de dureza SHORE D. En función de los resultados obtenidos se determinó que la probeta impresa en 3D con ABS ofrece mayor absorción de energía de impacto con respecto a la probeta de PLA; la estructura de relleno de la probeta que da mayor resistencia mecánica es la estructura cubica comparado con la estructura tri hexagonal. Además se determina que la dureza de la probeta de PLA es mayor que la probeta de ABS, finalmente se observó que la fractura de la probeta de PLA es lineal, mientras que la fractura de la probeta de ABS es tiene una forma de zigzag.
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Sedrati, Mouncef, Juan A. Morales, Abdelmounim El M’rini, Edward J. Anthony, Glen Bulot, Romain Le Gall et Abdelkarim Tadibaght. « Using UAV and Structure-From-Motion Photogrammetry for the Detection of Boulder Movement by Storms on a Rocky Shore Platform in Laghdira, Northwest Morocco ». Remote Sensing 14, no 16 (21 août 2022) : 4102. http://dx.doi.org/10.3390/rs14164102.
Texte intégralRésumé :
The detachment and mobilization of boulders from rocky shore platforms by waves involves complex geomorphic and hydrodynamic processes. Understanding these processes requires precise information on the rates and patterns of movement of these megaclasts scaled against the wave conditions that generate boulder mobility. Repeat photogrammetry and structure-from-motion (SfM) models commonly used in geomorphic analyses are an interesting option for monitoring boulder dynamics. In this study, we used unmanned aerial vehicle (UAV)-based digital photogrammetry and SfM differential models to identify recent boulder movements over a rocky shore platform in Laghdira, Morocco. Combining these results with data on storm occurrence in the study area allowed us to identify storm waves as the unique driver of the dislodged and mobilized boulders. The identified storm event had a significant wave height of 5.2 m. The UAV models were built from imagery captured in September and December 2019 using a DJI MAVIC PRO PLATINUM, and we used QGIS to produce 2D and 3D model outputs. The exploitation of the 2D model differentials allowed us to appreciate the response of the boulders to the storm waves and to determine platform volumetric changes and, therefore, boulder mobility. The 3D models were valuable in determining the mode of transport of the boulders. Mobility patterns included sliding, overturning with no further mobility, and rotation and saltation, as well as boulder breakup. Storm waves did not have a preferential impact on any particular boulder shape, size category, or position at the outer edge of the platform. These results highlight the utility of combining UAV surveys with identified storm events, which are much more frequent than tsunamis, in determining observed boulder initiation and mobility.
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Slapnik, Janez, Tanja Stiller, Thomas Wilhelm et Andreas Hausberger. « Influence of Solid Lubricants on the Tribological Performance of Photocurable Resins for Vat Photopolymerization ». Lubricants 8, no 12 (4 décembre 2020) : 104. http://dx.doi.org/10.3390/lubricants8120104.
Texte intégralRésumé :
New developments in additive manufacturing (AM) are enabling the use of 3D printed parts in increasingly demanding applications, such as in mechanical power transmission systems, where excellent build quality and tribological performance are required. The tribological properties of thermoplastic-based AM technologies are well knowninject, whereas the performance of photopolymer-based AM technologies is very rarely explored. This study aims to provide new insight into the tribological performance of 3D printed parts produced using vat photopolymerization (VPP). Photocurable resins based on aliphatic urethane acrylate oligomers were modified with different solid lubricants (polytetrafluoroethylene (PTFE), graphite and molybdenum disulfide (MoS2)) and 3D printed using Digital Light Processing (DLP). The mechanical and thermal properties were studied using the tensile tests, Charpy impact tests, Shore D, and dynamic mechanical analysis (DMA). The tribological performance was studied using a Pin-on-Disk tribometer. Among the lubricants, PTFE had the highest impact on the coefficient of friction (µ) and the specific wear rate (ws). The hybrid lubricant system (PTFE/MoS2) resulted in excellent tribological performance, where the µ was reduced by up to 52% and ws by up to 92%.
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Sharma, Kuldeep, et Kapil Kumar. « Parametric multi-objective optimization of fused deposition modelling (FDM) with biopolymer using Grey-Taguchi method ». IOP Conference Series : Materials Science and Engineering 1248, no 1 (1 juillet 2022) : 012107. http://dx.doi.org/10.1088/1757-899x/1248/1/012107.
Texte intégralRésumé :
Abstract For ecological sustainability, the synthetic polymers are being continuously replaced by biopolymers due to their unique properties of biocompatibility and biodegradability. Ploy-lactic acid (PLA) is a well-known engineering biopolymer because of its versatile use in bioengineering, textile and packing industries. For the customized engineering applications, the mechanical properties, namely tensile strength and shore hardness of PLA specimens printed by FDM which is an economical 3D printed technique has been investigated in this article. Taguchi’s L9 orthogonal array (OA) is used as a design of experiment. The influence of process parameters namely layer height, nozzle temperature, raster angle and surrounding pressure on mechanical properties of 3D printed specimens has been analysed by using Analysis of variance (ANOVA). ANOVA is employed to identify the significance and percent contribution of a particular process parameter on each mechanical property separately. In the end, grey relational analysis (GRA) is used as a multi-objective optimization tool to fabricate a better specimen with comprehensive mechanical properties.
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Park, Jieun, Minho Kim, Insic Hong, Taewi Kim, Eunhan Lee, Eun-a. Kim, Jae-Kwan Ryu et al. « Foot Plantar Pressure Measurement System Using Highly Sensitive Crack-Based Sensor ». Sensors 19, no 24 (13 décembre 2019) : 5504. http://dx.doi.org/10.3390/s19245504.
Texte intégralRésumé :
Measuring the foot plantar pressure has the potential to be an important tool in many areas such as enhancing sports performance, diagnosing diseases, and rehabilitation. In general, the plantar pressure sensor should have robustness, durability, and high repeatability, as it should measure the pressure due to body weight. Here, we present a novel insole foot plantar pressure sensor using a highly sensitive crack-based strain sensor. The sensor is made of elastomer, stainless steel, a crack-based sensor, and a 3D-printed frame. Insoles are made of elastomer with Shore A 40, which is used as part of the sensor, to distribute the load to the sensor. The 3D-printed frame and stainless steel prevent breakage of the crack-based sensor and enable elastic behavior. The sensor response is highly repeatable and shows excellent durability even after 20,000 cycles. We show that the insole pressure sensor can be used as a real-time monitoring system using the pressure visualization program.
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Specht, Cezary, Pawel S. Dabrowski et Mariusz Specht. « 3D modelling of beach topography changes caused by the tombolo phenomenon using terrestrial laser scanning (TLS) and unmanned aerial vehicle (UAV) photogrammetry on the example of the city of Sopot ». Geo-Marine Letters 40, no 5 (17 juin 2020) : 675–85. http://dx.doi.org/10.1007/s00367-020-00665-5.
Texte intégralRésumé :
Abstract In 2011, a yacht marina was built in Sopot (the largest holiday resort in Poland), which initiated the formation of a local shallowing of the bottom related to the tombolo effect. The building of the marina led to disturbances in the transmission of bottom deposits along the coast, which resulted from waves and the shift of the beach coastline by approx. 50 m towards the sea. Its effects include progressive morphological changes in the shore and the sea bottom, which will lead to the formation of a peninsula between the shore and the marina in the future. This paper presents the results of a comparative analysis of the accuracy of 3D modelling of the tombolo phenomenon in the onshore part of the beach using both point clouds obtained by terrestrial laser scanning methods and photogrammetric methods based on unmanned aerial vehicle photographs. The methods subjected to assessment include both those for land modelling and for determining the coastline course and its changes. The analysis results prove the existence of sub-metre differences in the imaged relief and the coastline course, which were demonstrated using an analysis of land cross-sections. The possibilities and limitations of both methods are demonstrated as well.
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Georgopoulou, Antonia, Silvain Michel et Frank Clemens. « Sensorized Robotic Skin Based on Piezoresistive Sensor Fiber Composites Produced with Injection Molding of Liquid Silicone ». Polymers 13, no 8 (10 avril 2021) : 1226. http://dx.doi.org/10.3390/polym13081226.
Texte intégralRésumé :
Soft robotics and flexible electronics are rising in popularity and can be used in many applications. However, there is still a need for processing routes that allow the upscaling in production for functional soft robotic parts in an industrial scale. In this study, injection molding of liquid silicone is suggested as a fabrication method for sensorized robotic skin based on sensor fiber composites. Sensor fibers based on thermoplastic elastomers with two different shore hardness (50A and 70A) are combined with different silicone materials. A mathematical model is used to predict the mechanical load transfer from the silicone matrix to the fiber and shows that the matrix of the lowest shore hardness should not be combined with the stiffer fiber. The sensor fiber composites are fixed on a 3D printed robotic finger. The sensorized robotic skin based on the composite with the 50A fiber in combination with pre-straining gives good sensor performance as well as a large elasticity. It is proposed that a miss-match in the mechanical properties between fiber sensor and matrix should be avoided in order to achieve low drift and relaxation. These findings can be used as guidelines for material selection for future sensor integrated soft robotic systems.
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Liu, Hongze, et Nobukazu Wakabayashi. « RedNavi : Building a 3D Scene of the Current Sea from AIS Data ». Sustainability 14, no 19 (2 octobre 2022) : 12572. http://dx.doi.org/10.3390/su141912572.
Texte intégralRésumé :
The Automatic Identification System (AIS) is a kind of navigation equipment that exchanges a wealth of essential information among vessels and between ships to shore through Very High Frequency. Currently, identification and other navigational information can be obtained in real time with AIS data integrated into other shipborne systems, such as the Electronic Chart Display and Information System and radar. However, at present, AIS information is represented in a two-dimensional (2D) way, which is not the same as the three-dimensional (3D) world people perceive visually. In this paper, we introduce RedNavi, a sustainable computer 3D scene building system that visualizes the current sea, specifically the environment and traffic conditions around the ownship, using received AIS data. RedNavi has a wide range of application scenarios. Applying to the maritime education and training field, it can serve as a bridge between the 2D and 3D worlds, helping less experienced trainees build up their capabilities. Applying to actual navigation, it can provide the deck officer with another visual aid to their lookout in addition to existing 2D information systems. In addition, given the microservices architecture RedNavi adopts, the development, deployment, and maintenance processes become relatively lighter, faster, and easier, and therefore more sustainable than traditional monolithic systems.
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Masnicki, Romuald, Cezary Specht, Janusz Mindykowski, Paweł Dąbrowski et Mariusz Specht. « Accuracy Analysis of Measuring X-Y-Z Coordinates with Regard to the Investigation of the Tombolo Effect ». Sensors 20, no 4 (20 février 2020) : 1167. http://dx.doi.org/10.3390/s20041167.
Texte intégralRésumé :
Tombolo is a narrow belt connecting the mainland with an island lying near the shore. It is formed as a result of sand and gravel being deposited by sea currents. In consequence, the seabed constantly rises and the shoreline moves towards the sea. This paper deals with accuracy analysis of the undertaken tombolo effect investigation, namely estimation of uncertainty of the measurement results. The aforementioned analysis concerns two methods used for creating a 3D beach model: Firstly, based on geodetic laser scanning (TLS—terrestrial laser scanning) and secondly, using images from unmanned aerial vehicles (UAV). The presented exemplary estimation of uncertainty of the measurement of coordinates X-Y-Z is based on the Polish case study.
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Benson, James, Regina Hanlon, Teresa Seifried, Philipp Baloh, Craig Powers, Hinrich Grothe et David Schmale. « Microorganisms Collected from the Surface of Freshwater Lakes Using a Drone Water Sampling System (DOWSE) ». Water 11, no 1 (16 janvier 2019) : 157. http://dx.doi.org/10.3390/w11010157.
Texte intégralRésumé :
New tools and technology are needed to study microorganisms in freshwater environments. Little is known about spatial distribution and ice nucleation activity (INA) of microorganisms in freshwater lakes. We developed a system to collect water samples from the surface of lakes using a 3D-printed sampling device tethered to a drone (DOWSE, DrOne Water Sampling SystEm). The DOWSE was used to collect surface water samples at different distances from the shore (1, 25, and 50 m) at eight different freshwater lakes in Austria in June 2018. Water samples were filtered, and microorganisms were cultured on two different media types, TSA (a general growth medium) and KBC (a medium semi-selective for bacteria in the genus Pseudomonas). Mean concentrations (colony forming units per mL, or CFU/mL) of bacteria cultured on TSA ranged from 19,800 (Wörthersee) to 210,500 (Gosaulacke) CFU/mL, and mean concentrations of bacteria cultured on KBC ranged from 2590 (Ossiachersee) to 11,000 (Vorderer Gosausee) CFU/mL. There was no significant difference in sampling distance from the shore for concentrations of microbes cultured on TSA (p = 0.28). A wireless bathymetry sensor was tethered to the drone to map temperature and depth across the sampling domain of each of the lakes. At the 50 m distance from the shore, temperature ranged from 17 (Hinterer Gosausee, and Gosaulacke) to 26 °C (Wörthersee), and depth ranged from 2.8 (Gosaulacke) to 11.1 m (Grundlsee). Contour maps of concentrations of culturable bacteria across the drone sampling domain revealed areas of high concentrations (hot spots) in some of the lakes. The percentage of ice-nucleation active (ice+) bacteria cultured on KBC ranged from 0% (0/64) (Wörthersee) to 58% (42/72) (Vorderer Gosausee), with a mean of 28% (153/544) for the entire sample set. Future work aims to elucidate the structure and function of entire microbial assemblages within and among the Austrian lakes.
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Kumar, Nirnimesh, et Falk Feddersen. « The Effect of Stokes Drift and Transient Rip Currents on the Inner Shelf. Part I : No Stratification ». Journal of Physical Oceanography 47, no 1 (janvier 2017) : 227–41. http://dx.doi.org/10.1175/jpo-d-16-0076.1.
Texte intégralRésumé :
AbstractThis is part one of a two-part study focused on Stokes drift and transient rip current (TRC) effects on the unstratified (this paper) and stratified (see Part II) inner shelf. A TRC-generating, wave-resolving model funwaveC is coupled to the 3D, wave-averaged wave and circulation model Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST). Two simulations (R1 and R2) are performed on an unstratified inner shelf and surfzone with typical bathymetry and wave conditions. R1 is a COAWST-only simulation (no TRCs), while R2 has funwaveC–COAWST coupling (with TRCs). R2 and funwaveC vertical vorticity (eddy) statistics are similar, indicating that the model coupling accurately generates TRCs, with TRC-induced eddies out to four surfzone widths offshore. R1 has a two-layered, inner-shelf-to-surfzone-connected, mean Lagrangian circulation, while R2 has separate inner shelf and surfzone circulation cells. The R2, TRC-induced, cross-shore and vertical eddy velocities are stronger than the R1 or R2 mean Lagrangian velocity out to four surfzone widths offshore. The R2, inner-shelf, mean, vertical eddy diffusivity is an order of magnitude larger than R1 out to four surfzone widths offshore. Both R1 and R2 are in a Stokes–Coriolis balance at six surfzone widths offshore, as is R1 at three surfzone widths offshore. For R2, TRC-induced horizontal advection and vertical mixing dominate the cross-shore momentum dynamics at three surfzone widths offshore. The R2 surfzone and inner-shelf cross-shore exchange velocity is 2–10 times larger for R1 because of the TRC-induced stirring. Accurate, unstratified, inner-shelf simulations of pollution, larval, or sediment transport must include transient rip currents. In Part II, the effects of Stokes drift and TRCs on the stratified inner shelf are examined.
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Marinho, Wellerson Salomão Diniz, Carlos Bruno Barreto Luna, Edcleide Maria Araújo, Carlos Heitor de Andrade Lustosa, Celso Rosendo Bezerra Filho et Raimundo Nonato Calazans Duarte. « From disposal to sustainable development : technological potential of poly(lactic acid) (PLA) blends with 3D filament waste ». Research, Society and Development 9, no 12 (15 décembre 2020) : e13291210767. http://dx.doi.org/10.33448/rsd-v9i12.10767.
Texte intégralRésumé :
Additive manufacturing is growing rapidly in the automotive, medical, and aerospace industries as an option for the manufacturing of products. However, there is a continuous growth in the amount of waste generated by 3D filaments, thus, the reuse practice becomes important, since it brings environmental and economic gains. The present research evaluated the mechanical, thermal, thermomechanical and rheological properties of PLA/PLAr blends containing post-consumption 3D filament. The blends were prepared in a co-rotational twin screw extruder and, subsequently, the extruded granules were injection molded. As the PLAr content in the blends (PLA/PLAr) increased, there was a reduction in viscosity, indicating an improvement in manufacturability. The PLA/PLAr blend (75/25 % wt.) increased the degree of crystallinity compared to neat PLA, indicating that PLAr acted as a nucleating agent. As a consequence, the PLA/PLAr blend (75/25 % wt.) showed performance comparable to neat PLA in thermal stability, elastic modulus, tensile strength, Shore D hardness, impact strength, heat deflection temperature (HDT) and Vicat softening temperature. The reuse of post-consumption 3D filament PLA is feasible for the development of materials with good properties. In addition, value is added to the post-consumption material and there is a contribution to sustainable development.
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Czajkowska, Marta, Ewa Walejewska, Łukasz Zadrożny, Monika Wieczorek, Wojciech Święszkowski, Leopold Wagner, Eitan Mijiritsky et Jarosław Markowski. « Comparison of Dental Stone Models and Their 3D Printed Acrylic Replicas for the Accuracy and Mechanical Properties ». Materials 13, no 18 (13 septembre 2020) : 4066. http://dx.doi.org/10.3390/ma13184066.
Texte intégralRésumé :
This study was conducted to test possibilities of application of 3D printed dental models (DMs) in terms of their accuracy and physical properties. In this work, stone models of mandibles were cast from alginate impressions of 10 patients and scanned in order to obtain 3D printed acrylic replicas. The diagnostic value was tested as matching of model scans on three levels: peak of cusps, occlusal surface, and all teeth surfaces. The mechanical properties of acrylic and stone samples, specifically the impact strength, shore D hardness, and flexural and compressive strength were investigated according to ISO standards. The matching of models’ surfaces was the highest on the level of peaks of cusps (average lack of deviations, 0.21 mm) and the lowest on the level of all teeth surfaces (average lack of deviations, 0.64 mm). Acrylic samples subjected to mechanical testing, as expected, showed higher mechanical properties as compared to the specimens made of dental stone. In the present study we demonstrated that 3D printed acrylic models could be ideal representatives in the case of use as a diagnostic tool and as a part of medical records. The acrylic samples exhibited not only higher mechanical properties, but also showed better accuracy comparing to dental stone.
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Mau, Robert, Jamal Nazir, Samuel John et Hermann Seitz. « Preliminary Study on 3D printing of PEGDA Hydrogels for Frontal Sinus Implants using Digital Light Processing (DLP) ». Current Directions in Biomedical Engineering 5, no 1 (1 septembre 2019) : 249–52. http://dx.doi.org/10.1515/cdbme-2019-0063.
Texte intégralRésumé :
AbstractDigital Light Processing (DLP) enables high precision 3D-printing of photopolymers and holds promising potential for patient-specific implant solutions. On the material side, Poly(ethylene glycol) diacrylate (PEGDA) has emerged as an interesting material for use in biomedical applications. For adequate photopolymerization, a photoinitiator and a light absorber are necessary, using welldefined concentrations. This study shows preliminary results of DLP 3D-printing of different PEGDA hydrogel compositions with varying water content (90; 70; 50; 30; 10; 0 % w/w) as well as varying concentrations of a photoinitiator and a light absorber. Printing performance and accuracy are investigated by printing rectangular test samples as well as an anatomically customised tubular frontal sinus implant prototype. For basic mechanical characterisation, the hardness of the printed hydrogels is investigated using a Shore A durometer. The results show a decrease in printing accuracy and hardness with an increasing water content of the composition. There is a need to use a light absorber to reach high printing accuracy. This leads to a need for increasing photoinitiator concentration and prolonged light exposure to achieve proper printing performance.
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Guimarães, André, Carlos Coelho, Fernando Veloso-Gomes et Paulo A. Silva. « 3D Physical Modeling of an Artificial Beach Nourishment : Laboratory Procedures and Nourishment Performance ». Journal of Marine Science and Engineering 9, no 6 (3 juin 2021) : 613. http://dx.doi.org/10.3390/jmse9060613.
Texte intégralRésumé :
Beach nourishment represents a type of coastal defense intervention, keeping the beach as a natural coastal defense system. Altering the cross-shore profile geometry, due to the introduction of new sediments, induces a non-equilibrium situation regarding the local wave dynamics. This work aims to increase our knowledge concerning 3D movable bed physical modeling and beach nourishment impacts on the hydrodynamics, sediment transport, and morphodynamics. A set of experiments with an artificial beach nourishment movable bed model was prepared. Hydrodynamic, sediment transport, and morphological variations and impacts due to the presence of the nourishment were monitored with specific equipment. Special attention was given to the number and positioning of the monitoring equipment and the inherent constraints of 3D movable beds laboratory tests. The nourishment induced changes in the beach dynamics, leading to an increase in the flow velocities range and suspended sediment concentration, and effectively increasing the emerged beach width. Predicting and anticipating the morphological evolution of the modeled beach has a major impact on data accuracy, since it might influence the monitoring equipment’s correct position. Laboratory results and constraints were characterized to help better define future laboratory procedures and strategies for increasing movable bed models’ accuracy and performance.
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George, Douglas A., John L. Largier, Gregory Brian Pasternack, Patrick L. Barnard, Curt D. Storlazzi et Li H. Erikson. « Modeling Sediment Bypassing around Idealized Rocky Headlands ». Journal of Marine Science and Engineering 7, no 2 (7 février 2019) : 40. http://dx.doi.org/10.3390/jmse7020040.
Texte intégralRésumé :
Alongshore sediment bypassing rocky headlands remains understudied despite the importance of characterizing littoral processes for erosion abatement, beach management, and climate change adaptation. To address this gap, a numerical model sediment transport study was developed to identify controlling factors and mechanisms for sediment headland bypassing potential. Four idealized headlands were designed to investigate sediment flux around the headlands using the process-based hydrodynamic model Delft-3D and spectral wave model SWAN. The 120 simulations explored morphologies, substrate compositions, sediment grain sizes, and physical forcings (i.e., tides, currents, and waves) commonly observed in natural settings. A generalized analytical framework based on flow disruption and sediment volume was used to refine which factors and conditions were more useful to address sediment bypassing. A bypassing parameter was developed for alongshore sediment flux between upstream and downstream cross-shore transects to determine the degree of blockage by a headland. The shape of the headland heavily influenced the fate of the sediment by changing the local angle between the shore and the incident waves, with oblique large waves generating the most flux. All headlands may allow sediment flux, although larger ones blocked sediment more effectively, promoting their ability to be littoral cell boundaries. The controlling factors on sediment bypassing were determined to be wave angle, size, and shape of the headland, and sediment grain size.
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Iman, Miftahul, et Azis Susanto. « EVALUASI KINERJA STRUKTUR MENARA RANGKA BAJA (DERRICK) BERDASARKAN PERIODE AISC ». Jurnal Kacapuri : Jurnal Keilmuan Teknik Sipil 3, no 1 (24 octobre 2020) : 96. http://dx.doi.org/10.31602/jk.v3i1.3605.
Texte intégralRésumé :
Tarakan adalah kota penghasil minyak yang telah dikenal sejak 1896. Derrick didefinisikan sebagai fasilitas pengeboran minyak bumi. Prototipe derrick dimodelkan dengan elemen rangka 3D dalam SAP2000. Tiga standar telah digunakan seperti AISC- ASD 1983; AISC-LRFD 1993; dan AISC 2010. Kombinasi beban angin (W) dan gempa (E) telah dibandingkan. Analisis tekuk tunggal dan keseluruhan telah dipertimbangkan. Hasil penelitian menunjukkan bahwa struktur derick memenuhi persyaratan stabilitas dan kekuatan. Pengaruh kombinasi beban angin (W) pada struktur derek lebih signifikan (9,45%) daripada beban gempa (E). Beban tekan aksial terbesar maksimum 9,37 kN pada elemen kaki (legs). Kegagalan tekuk tidak terjadi pada struktur derrick. Beban kritis (Pcr) tercatat 700,45 kN (Euler), 693,41 kN (tunggal), dan 219,67 kN (struktur). Kata Kunci: tekuk, on shore, kapasitas, angin, rig
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Angelelli, Elisa, et Barbara Zanuttigh. « A FARM OF WAVE ACTIVATED BODIES FOR COASTAL PROTECTION PURPOSES ». Coastal Engineering Proceedings 1, no 33 (15 décembre 2012) : 68. http://dx.doi.org/10.9753/icce.v33.structures.68.
Texte intégralRésumé :
This paper aims at investigating the efficacy of a floating farm of wave energy converters for coastal protection purposes through physical and numerical modelling. The experiments were performed in 3D conditions on a basic module consisting of two staggered lines and three devices. The numerical simulations were carried out with the software MIKE 21 BW, developed by DHI Water & Environment & Health, and were calibrated based on the experimental results. Additional configurations were tested by varying the gap long-shore width and the device alignment. Despite the model limitations, i.e. the representation of the devices as fixed porous piles, the numerical results well approximate the average measured transmission coefficient and allow to derive a complete map of the hydrodynamics around the devices.
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Cardona, Camilo Jaramillo, Jara Martinez Sanchez, Mauricio Gonzalez Rodriguez et Raul Medina Santamaria. « A SHORELINE EVOLUTION MODEL BASED ON EQUILIBRIUM FORMULATIONS ». Coastal Engineering Proceedings, no 36v (28 décembre 2020) : 19. http://dx.doi.org/10.9753/icce.v36v.sediment.19.
Texte intégralRésumé :
Traditionally, the shoreline hindcast under the influence of changing marine conditions has been considered by means of existing robust shoreline evolution models, such as one-line, multi-line, combined or 3D models. All of them require long data series, many calibration parameters and are computationally intensive. This study presents a new shoreline evolution model considering the integration of cross-shore, planform and rotation equilibrium-based models, applicable over time-scales spanning days, months or several years. The new model successfully reaches the general erosion-accretion trend at a qualitative and quantitative level. As the main conclusion, this is a simple equilibrium-based shoreline evolution model that requires few calibration parameters and is computationally efficient and versatile.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/zkQ7AoAWmEE
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Kopteva, Anna, et Alexey Lukin. « Constructive features of the bank protection structure of water recreation facility in Arkhangelsk ». MATEC Web of Conferences 170 (2018) : 03025. http://dx.doi.org/10.1051/matecconf/201817003025.
Texte intégralRésumé :
The objective of the study is projecting and calculation of shore protection structure of the water recreation facility in northern climatic conditions of Arkhangelsk city. In the course of study, three constructive solutions including anchored or non-anchored Larsen dowel wall were projected based on geotechnical conditions of Arkhangelsk. Geotechnical conditions include physico-mechanical and strength characteristics of soils, determined in accordance with the geological regulations. The calculation of bank protection structures was performed in PLAXIS 3D Foundation package by the finite element method. The study represents diagrams and graphics showing the deformations of bank protection structure. The result of the study is a solution chosen according to the reliability criterion. Recommendations and directions for the future research were proposed.
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Weisson, Ernesto H., Mauro Fittipaldi, Carlos A. Concepcion, Daniel Pelaez, Landon Grace et David T. Tse. « Automatisiertes kontaktloses Mapping der Gesichtstopographie, 3-dimensionaler Druck und Silikonguss von Orbitalprothesen ». Kompass Ophthalmologie 8, no 4 (2022) : 171–79. http://dx.doi.org/10.1159/000527589.
Texte intégralRésumé :
<b>Zweck:</b> Eine Proof-of-Concept-Workflow-Studie zur Herstellung von maßgefertigten Orbitalprothesen nach Exenteration durch automatisierten kontaktlosen Scan, 3D-Druck und Silikonguss. <b>Ausführung:</b> Nicht vergleichende, interventionelle Fallreihe. · <underline>Setting</underline>: Monozentrische institutionelle Studie. · <underline>Studienpopulation</underline>: Drei Patienten, die das Tragen der vom Okularisten hergestellten Exenterationsprothese aufgrund veränderter Passform, Verfärbung oder Materialdegradation eingestellt haben. · <underline>Interventionsverfahren</underline>: Mithilfe kontaktlosen Gesichtstopographiemappings wurde ein digitales Abbild der exenterierten Augenhöhle und der kontralateralen periokularen Region erfasst. Die digitale Konstruktion der vorderen Prothesenoberfläche basierte auf dem gespiegelten Bild der kontralateralen Seite und die hintere Oberflächenkontur auf der Geometrie der Augenhöhle. Die Details der vorderen und hinteren Oberfläche wurden digital zusammengeführt. Im 3D-Drucker wurde eine zweiteilige Form entworfen und hergestellt. Mithilfe der Kolorimetrie wurde eine individuelle Pigmentmischung für das Shore 40-Silikonelastomer erstellt, um eine Prothese zu erzeugen, die dem Hautton des Patienten nahekommt. · <underline>Wichtigste Zielparameter</underline>: Prothesensymmetrie, Übereinstimmung mit Hautton, Tragekomfort und Kosmese. <b>Ergebnisse:</b> Das erste Exemplar jeder 3D-gedruckten Orbitalprothese, die in diesem Produktionsworkflow hergestellt wurde, wies eine gute Symmetrie, Farbübereinstimmung und Passgenauigkeit der Prothese auf. In einem Fall wurde das neu konturierte zweite Exemplar mit verbesserter Prothesenkante an der Haut in Abwesenheit des Patienten angefertigt. <b>Fazit:</b> Ein kontaktloser 3D-Scan, computergestütztes Design, 3D-Druck und Silikonguss zur Herstellung von Orbitalprothesen wurden entwickelt und validiert. Dieser Produktionsworkflow hat das Potenzial, effiziente, standardisierte und reproduzierbare Exenterationsprothesen zu liefern und die Haupthindernisse für erschwingliche maßgefertigte Prothesen weltweit zu überwinden: Zugänglichkeit und Kosten.
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Schlégl, Ádám Tibor, Roland Told, Kinga Kardos, András Szőke, Zoltan Ujfalusi et Péter Maróti. « Evaluation and Comparison of Traditional Plaster and Fiberglass Casts with 3D-Printed PLA and PLA–CaCO3 Composite Splints for Bone-Fracture Management ». Polymers 14, no 17 (30 août 2022) : 3571. http://dx.doi.org/10.3390/polym14173571.
Texte intégralRésumé :
Bone fractures pose a serious challenge for the healthcare system worldwide. A total of 17.5% of these fractures occur in the distal radius. Traditional cast materials commonly used for treatment have certain disadvantages, including a lack of mechanical and water resistance, poor hygiene, and odors. Three-dimensional printing is a dynamically developing technology which can potentially replace the traditional casts. The aim of the study was to examine and compare the traditional materials (plaster cast and fiberglass cast) with Polylactic Acid (PLA) and PLA–CaCO3 composite materials printed using Fused Filament Fabrication (FFF) technology and to produce a usable cast of each material. The materials were characterized by tensile, flexural, Charpy impact, Shore D hardness, flexural fatigue, and variable load cyclic tests, as well as an absorbed water test. In addition, cost-effectiveness was evaluated and compared. The measured values for tensile strength and flexural strength decreased with the increase in CaCO3 concentration. In the fatigue tests, the plaster cast and the fiberglass cast did not show normal fatigue curves; only the 3D-printed materials did so. Variable load cyclic tests showed that traditional casts cannot hold the same load at the same deflection after a higher load has been used. During these tests, the plaster cast had the biggest relative change (−79.7%), compared with −4.8 % for the 3D-printed materials. The results clearly showed that 3D-printed materials perform better in both static and dynamic mechanical tests; therefore, 3D printing could be a good alternative to customized splints and casts in the near future.