Grups de recercahttp://hdl.handle.net/2117/285812024-03-19T03:34:59Z2024-03-19T03:34:59ZAssessment of a clinical test for detection of alteration in visual perception due to astigmatismGal, EyalGispets Parcerisas, JoanWilkins, ArnoldZyroff, MeiraNetanya, EfratGantz, Liathttp://hdl.handle.net/2117/4048802024-03-18T16:00:40Z2024-03-18T15:58:02ZAssessment of a clinical test for detection of alteration in visual perception due to astigmatism
Gal, Eyal; Gispets Parcerisas, Joan; Wilkins, Arnold; Zyroff, Meira; Netanya, Efrat; Gantz, Liat
Purpose: Astigmatism blurs the retinal image of a circular spot along a particular orientation rendering it an elliptical shape. Astigmatic patients demonstrate adaptation to residual astigmatic blur that may affect their discrimination between oval and circular targets. The Wilkins Egg and Ball Test (WEBT) was created to detect altered visual perception due to residual astigmatic blur by discriminating a circle within a row of oval elements. This prospective, cross-sectional study examined the utility of WEBT in detecting uncorrected residual astigmatism on the perception of form symmetry in astigmatic and keratoconic participants as well as normal participants with induced astigmatism at four primary meridians. Methods: The mean search time (sT) and number of errors (noE) of 33 non-astigmatic controls (mean age: 24±5, range: 18–43, 6 males), 23 astigmatic participants (mean age: 36±12, range: 18–43, 6 males) and 13 keratoconic participants (N=22 eyes, mean age: 36 ±12, range: 18–58, 6 males) were measured under baseline, and 2.00 DC induced cylinder at four primary meridians, and for uncorrected, spherical-correction only, and fully corrected conditions, respectively. Mean sT and noE were converted to Z-scores, combined for each condition, and compared using repeated measures ANOVA with post-hoc analysis. Results: Combined Z-scores for the controls were significantly worse (p<0.001) for all induced cylinder conditions. The induced 180° condition was significantly better than 45° and 90° conditions (p=0.04), but not the 135° condition. For both astigmatic and keratoconic cohorts, Z-scores of the uncorrected condition were significantly worse than the fully corrected condition (both p<0.01), but the fully corrected and spherical-only conditions did not differ significantly (p=0.06 and p=0.05, respectively). Conclusion: In accommodating young adults, WEBT detected altered visual perception due to overall blur, and moderate-high amounts of uncorrected induced astigmatism and keratoconus, but is not useful as a tool for detection of altered visual perception due to small residual astigmatic blur.
2024-03-18T15:58:02ZGal, EyalGispets Parcerisas, JoanWilkins, ArnoldZyroff, MeiraNetanya, EfratGantz, LiatPurpose: Astigmatism blurs the retinal image of a circular spot along a particular orientation rendering it an elliptical shape. Astigmatic patients demonstrate adaptation to residual astigmatic blur that may affect their discrimination between oval and circular targets. The Wilkins Egg and Ball Test (WEBT) was created to detect altered visual perception due to residual astigmatic blur by discriminating a circle within a row of oval elements. This prospective, cross-sectional study examined the utility of WEBT in detecting uncorrected residual astigmatism on the perception of form symmetry in astigmatic and keratoconic participants as well as normal participants with induced astigmatism at four primary meridians. Methods: The mean search time (sT) and number of errors (noE) of 33 non-astigmatic controls (mean age: 24±5, range: 18–43, 6 males), 23 astigmatic participants (mean age: 36±12, range: 18–43, 6 males) and 13 keratoconic participants (N=22 eyes, mean age: 36 ±12, range: 18–58, 6 males) were measured under baseline, and 2.00 DC induced cylinder at four primary meridians, and for uncorrected, spherical-correction only, and fully corrected conditions, respectively. Mean sT and noE were converted to Z-scores, combined for each condition, and compared using repeated measures ANOVA with post-hoc analysis. Results: Combined Z-scores for the controls were significantly worse (p<0.001) for all induced cylinder conditions. The induced 180° condition was significantly better than 45° and 90° conditions (p=0.04), but not the 135° condition. For both astigmatic and keratoconic cohorts, Z-scores of the uncorrected condition were significantly worse than the fully corrected condition (both p<0.01), but the fully corrected and spherical-only conditions did not differ significantly (p=0.06 and p=0.05, respectively). Conclusion: In accommodating young adults, WEBT detected altered visual perception due to overall blur, and moderate-high amounts of uncorrected induced astigmatism and keratoconus, but is not useful as a tool for detection of altered visual perception due to small residual astigmatic blur.Toughening 3D printed biomimetic hydroxyapatite scaffolds: polycaprolactone-based self-hardening inksMazo Bárbara, Laura delJohansson, Linh Ha Huong LovisaTampieri, FrancescoGinebra Molins, Maria Pauhttp://hdl.handle.net/2117/4048792024-03-18T16:00:19Z2024-03-18T15:53:52ZToughening 3D printed biomimetic hydroxyapatite scaffolds: polycaprolactone-based self-hardening inks
Mazo Bárbara, Laura del; Johansson, Linh Ha Huong Lovisa; Tampieri, Francesco; Ginebra Molins, Maria Pau
The application of 3D printing to calcium phosphates has opened unprecedented possibilities for the fabrication of personalized bone grafts. However, their biocompatibility and bioactivity are counterbalanced by their high brittleness. In this work we aim at overcoming this problem by developing a self-hardening ink containing reactive ceramic particles in a polycaprolactone solution instead of the traditional approach that use hydrogels as binders. The presence of polycaprolactone preserved the printability of the ink and was compatible with the hydrolysis-based hardening process, despite the absence of water in the ink and its hydrophobicity. The microstructure evolved from a continuous polymeric phase with loose ceramic particles to a continuous network of hydroxyapatite nanocrystals intertwined with the polymer, in a configuration radically different from the polymer/ceramic composites obtained by fused deposition modelling. This resulted in the evolution from a ductile behavior, dominated by the polymer, to a stiffer behavior as the ceramic phase reacted. The polycaprolactone binder provides two highly relevant benefits compared to hydrogel-based inks. First, the handleability and elasticity of the as-printed scaffolds, together with the proven possibility of eliminating the solvent, opens the door to implanting the scaffolds freshly printed once lyophilized, while in a ductile state, and the hardening process to take place inside the body, as in the case of calcium phosphate cements. Second, even with a hydroxyapatite content of more than 92%, the flexural strength and toughness of the scaffolds after hardening are twice and five times those of the all-ceramic scaffolds obtained with the hydrogel-based inks, respectively.
2024-03-18T15:53:52ZMazo Bárbara, Laura delJohansson, Linh Ha Huong LovisaTampieri, FrancescoGinebra Molins, Maria PauThe application of 3D printing to calcium phosphates has opened unprecedented possibilities for the fabrication of personalized bone grafts. However, their biocompatibility and bioactivity are counterbalanced by their high brittleness. In this work we aim at overcoming this problem by developing a self-hardening ink containing reactive ceramic particles in a polycaprolactone solution instead of the traditional approach that use hydrogels as binders. The presence of polycaprolactone preserved the printability of the ink and was compatible with the hydrolysis-based hardening process, despite the absence of water in the ink and its hydrophobicity. The microstructure evolved from a continuous polymeric phase with loose ceramic particles to a continuous network of hydroxyapatite nanocrystals intertwined with the polymer, in a configuration radically different from the polymer/ceramic composites obtained by fused deposition modelling. This resulted in the evolution from a ductile behavior, dominated by the polymer, to a stiffer behavior as the ceramic phase reacted. The polycaprolactone binder provides two highly relevant benefits compared to hydrogel-based inks. First, the handleability and elasticity of the as-printed scaffolds, together with the proven possibility of eliminating the solvent, opens the door to implanting the scaffolds freshly printed once lyophilized, while in a ductile state, and the hardening process to take place inside the body, as in the case of calcium phosphate cements. Second, even with a hydroxyapatite content of more than 92%, the flexural strength and toughness of the scaffolds after hardening are twice and five times those of the all-ceramic scaffolds obtained with the hydrogel-based inks, respectively.Biodegradable conducting PVA-hydrogel based on carbon quantum dots: study of the synergistic effect of additivesGamboa Rivera, Jillian TriciaPaulo Mirasol, SofiaEspona Noguera, AlbertEnshaei, HamidrezaOrtiz Rojas, SergioEstrany Coda, FrancescGinebra Molins, Maria PauTorras Costa, Juanhttp://hdl.handle.net/2117/4048692024-03-18T15:30:38Z2024-03-18T15:27:04ZBiodegradable conducting PVA-hydrogel based on carbon quantum dots: study of the synergistic effect of additives
Gamboa Rivera, Jillian Tricia; Paulo Mirasol, Sofia; Espona Noguera, Albert; Enshaei, Hamidreza; Ortiz Rojas, Sergio; Estrany Coda, Francesc; Ginebra Molins, Maria Pau; Torras Costa, Juan
Conductive hydrogels are becoming one of the most important milestones for the development of new scaffolds, biosensors, supercapacitors, and green electronics within the field of biomedicine. In this work, we study the effect of different types of electroactive additives such as poly(3,4-ethylenedioxythiophene), tannic acid, and carbon quantum dots (CQDs), to form different poly(vinyl alcohol) (PVA)-based hydrogels with enhanced electrochemical properties. Different physicochemical tests are carried out to characterize the different PVA-based hybrid hydrogels and the rates of their degradation and loss of electroactivity throughout an eight-week biodegradation process. This work shows the individual and synergistic effects of the additives on various mechanical properties, including storage modulus and swelling ratio, and electrochemical properties of the PVA hydrogel. The additives have proven to enhance the electroactivity of the PVA-based hydrogels but as well their degradation. Finally, the use of the new hydrogel as a pressure sensor is also investigated. The study provides an insight on the potential use of CQDs, in synergy with other electroactivity enhancers, in the fabrication of novel hybrid conducting hydrogels in green electronics.
2024-03-18T15:27:04ZGamboa Rivera, Jillian TriciaPaulo Mirasol, SofiaEspona Noguera, AlbertEnshaei, HamidrezaOrtiz Rojas, SergioEstrany Coda, FrancescGinebra Molins, Maria PauTorras Costa, JuanConductive hydrogels are becoming one of the most important milestones for the development of new scaffolds, biosensors, supercapacitors, and green electronics within the field of biomedicine. In this work, we study the effect of different types of electroactive additives such as poly(3,4-ethylenedioxythiophene), tannic acid, and carbon quantum dots (CQDs), to form different poly(vinyl alcohol) (PVA)-based hydrogels with enhanced electrochemical properties. Different physicochemical tests are carried out to characterize the different PVA-based hybrid hydrogels and the rates of their degradation and loss of electroactivity throughout an eight-week biodegradation process. This work shows the individual and synergistic effects of the additives on various mechanical properties, including storage modulus and swelling ratio, and electrochemical properties of the PVA hydrogel. The additives have proven to enhance the electroactivity of the PVA-based hydrogels but as well their degradation. Finally, the use of the new hydrogel as a pressure sensor is also investigated. The study provides an insight on the potential use of CQDs, in synergy with other electroactivity enhancers, in the fabrication of novel hybrid conducting hydrogels in green electronics.Marked graphs and the chromatic symmetric functionAliste Prieto, JoséMier Vinué, Anna deOrellana, RosaZamora Ponce, Joséhttp://hdl.handle.net/2117/4048302024-03-18T12:40:14Z2024-03-18T12:32:58ZMarked graphs and the chromatic symmetric function
Aliste Prieto, José; Mier Vinué, Anna de; Orellana, Rosa; Zamora Ponce, José
The main result of this paper is the introduction of marked graphs and the marked graph polynomials ( -polynomial) associated with them. These polynomials can be defined via a deletion-contraction operation. These polynomials are a generalization of the -polynomial, introduced by Noble and Welsh, and a specialization of the -polynomial, introduced by Ellis-Monaghan and Moffatt. In addition, we describe an important specialization of the -polynomial, which we call the -polynomial. Furthermore, we present an efficient algorithm for computing the chromatic symmetric function of a graph in the star basis of symmetric functions. As an application of these tools, we prove that proper trees of diameter at most 5 are reconstructible from its chromatic symmetric function.
2024-03-18T12:32:58ZAliste Prieto, JoséMier Vinué, Anna deOrellana, RosaZamora Ponce, JoséThe main result of this paper is the introduction of marked graphs and the marked graph polynomials ( -polynomial) associated with them. These polynomials can be defined via a deletion-contraction operation. These polynomials are a generalization of the -polynomial, introduced by Noble and Welsh, and a specialization of the -polynomial, introduced by Ellis-Monaghan and Moffatt. In addition, we describe an important specialization of the -polynomial, which we call the -polynomial. Furthermore, we present an efficient algorithm for computing the chromatic symmetric function of a graph in the star basis of symmetric functions. As an application of these tools, we prove that proper trees of diameter at most 5 are reconstructible from its chromatic symmetric function.Generación sintética de trayectorias mediante aprendizaje profundo con garantías de privacidad diferencialRubio Jornet, VictorParra Arnau, JavierForné Muñoz, Jorgehttp://hdl.handle.net/2117/4048292024-03-18T12:26:11Z2024-03-18T12:19:29ZGeneración sintética de trayectorias mediante aprendizaje profundo con garantías de privacidad diferencial
Rubio Jornet, Victor; Parra Arnau, Javier; Forné Muñoz, Jorge
La generación sintética de trayectorias es cru- cial para poder realizar estudios y análisis en diferentes campos, como la movilidad urbana, los protocolos de redes móviles, la epidemiología computacional o la simulación de cambios en la movilidad para la planificación urbana. Actual- mente, se ha observado que la generación de datos sintéticos sin protección adicional puede poner en riesgo la privacidad de los usuarios, dado que los modelos de aprendizaje profundo actuales son ataques de inferencia de membresía. un modelo de aprendizaje profundo ya existente llamado MoveSim, el cual genera datos sintéticos Este modelo ha sido modificado ferencialmente privado y, de esta manera, garantizar la privacidad de los usuarios que han proporcionado sus datos sin perder un rendimiento sustancial del modelo.
2024-03-18T12:19:29ZRubio Jornet, VictorParra Arnau, JavierForné Muñoz, JorgeLa generación sintética de trayectorias es cru- cial para poder realizar estudios y análisis en diferentes campos, como la movilidad urbana, los protocolos de redes móviles, la epidemiología computacional o la simulación de cambios en la movilidad para la planificación urbana. Actual- mente, se ha observado que la generación de datos sintéticos sin protección adicional puede poner en riesgo la privacidad de los usuarios, dado que los modelos de aprendizaje profundo actuales son ataques de inferencia de membresía. un modelo de aprendizaje profundo ya existente llamado MoveSim, el cual genera datos sintéticos Este modelo ha sido modificado ferencialmente privado y, de esta manera, garantizar la privacidad de los usuarios que han proporcionado sus datos sin perder un rendimiento sustancial del modelo.Extending the electric vehicle battery first life: performance beyond the current end of life thresholdEtxandi Santolaya, MaiteCanals Casals, LlucCorchero Garcia, Cristinahttp://hdl.handle.net/2117/4048252024-03-18T12:00:23Z2024-03-18T11:55:17ZExtending the electric vehicle battery first life: performance beyond the current end of life threshold
Etxandi Santolaya, Maite; Canals Casals, Lluc; Corchero Garcia, Cristina
Presently, Electric Vehicle batteries are considered to have reached the End of Life once their State of Health falls to 70-80%. However, this criteria is universal to all battery capacities and not based on the specific application requirements. To evaluate whether the End of Life can be extended below the current threshold, the impact of the Internal Resistance increase needs to be addressed. In this sense, this study employs a degradation aware electrothermal model to evaluate the battery performance for different use cases. The findings reveal that capacity constraints are the main cause of the End of Life, followed by power constraints. However, this is highly dependent on the battery capacity. Large capacity batteries tend to reach the End of Life for capacity constraints, whereas smaller ones show power limitations first. The temperature increase has not shown to be a restriction for any of the cases simulated. The decline in performance is for most cases (37.5% of the simulated ones) noticed below 70% State of Health, supporting that the first-life of most batteries can be extended without compromising the vehicle’s performance. This is especially the case for most average drivers using large battery capacities, currently emerging on the market. The methodology proposed for the simulated cases can be extended to real time operation in the Battery Management System. Estimating the End of Life in this way can support the maximization of the first-life and only requires an appropriate use of the available data.
2024-03-18T11:55:17ZEtxandi Santolaya, MaiteCanals Casals, LlucCorchero Garcia, CristinaPresently, Electric Vehicle batteries are considered to have reached the End of Life once their State of Health falls to 70-80%. However, this criteria is universal to all battery capacities and not based on the specific application requirements. To evaluate whether the End of Life can be extended below the current threshold, the impact of the Internal Resistance increase needs to be addressed. In this sense, this study employs a degradation aware electrothermal model to evaluate the battery performance for different use cases. The findings reveal that capacity constraints are the main cause of the End of Life, followed by power constraints. However, this is highly dependent on the battery capacity. Large capacity batteries tend to reach the End of Life for capacity constraints, whereas smaller ones show power limitations first. The temperature increase has not shown to be a restriction for any of the cases simulated. The decline in performance is for most cases (37.5% of the simulated ones) noticed below 70% State of Health, supporting that the first-life of most batteries can be extended without compromising the vehicle’s performance. This is especially the case for most average drivers using large battery capacities, currently emerging on the market. The methodology proposed for the simulated cases can be extended to real time operation in the Battery Management System. Estimating the End of Life in this way can support the maximization of the first-life and only requires an appropriate use of the available data.Harnessing disulfide and transesterification bond exchange reactions for recyclable and reprocessable 3D-printed vitrimersVilanova Pérez, AnnaMoradi, SasanKonuray, Ali OsmanRamis Juan, XavierRoig Gibert, AdriáFernández Francos, Xavierhttp://hdl.handle.net/2117/4048092024-03-18T11:30:22Z2024-03-18T11:26:55ZHarnessing disulfide and transesterification bond exchange reactions for recyclable and reprocessable 3D-printed vitrimers
Vilanova Pérez, Anna; Moradi, Sasan; Konuray, Ali Osman; Ramis Juan, Xavier; Roig Gibert, Adriá; Fernández Francos, Xavier
Two new vitrimeric materials have been studied for potential additive manufacturing applications such as 3D- printing. A monomer containing disulfide bonds and ß-hydroxyesters was easily synthesized from two low- cost and commercially available reagents. Another disulfide-containing monomer was synthesized for compar- ison purposes. Materials were prepared through a UV-light radical polymerization of methacrylates. The addition of two reactive diluents such as poly(ethylene glycol) methyl ether methacrylate (PEGMA) and ethylene glycol phenyl ether methacrylate (EGPMA) was necessary to achieve a suitable viscosity for the curing as well as for their printability. The curing process was controlled by FTIR. Thermomechanical properties were investigated by means of DMTA analysis revealing near-ambient Tg values. Stress relaxation tests revealed that both materials were capable to relax the 63% of the initial stress in less than 10 min at 110 ¿C. The recyclability of the materials was achieved, and the mechanical and thermomechanical properties of the recycled samples were compared to the virgin ones revealing a great recovery of the initial properties. Finally, Digital Light Processing (DLP) technique was used to print complex structures with high resolution highlighting the great potential of these vitrimeric materials in 3D printing.
2024-03-18T11:26:55ZVilanova Pérez, AnnaMoradi, SasanKonuray, Ali OsmanRamis Juan, XavierRoig Gibert, AdriáFernández Francos, XavierTwo new vitrimeric materials have been studied for potential additive manufacturing applications such as 3D- printing. A monomer containing disulfide bonds and ß-hydroxyesters was easily synthesized from two low- cost and commercially available reagents. Another disulfide-containing monomer was synthesized for compar- ison purposes. Materials were prepared through a UV-light radical polymerization of methacrylates. The addition of two reactive diluents such as poly(ethylene glycol) methyl ether methacrylate (PEGMA) and ethylene glycol phenyl ether methacrylate (EGPMA) was necessary to achieve a suitable viscosity for the curing as well as for their printability. The curing process was controlled by FTIR. Thermomechanical properties were investigated by means of DMTA analysis revealing near-ambient Tg values. Stress relaxation tests revealed that both materials were capable to relax the 63% of the initial stress in less than 10 min at 110 ¿C. The recyclability of the materials was achieved, and the mechanical and thermomechanical properties of the recycled samples were compared to the virgin ones revealing a great recovery of the initial properties. Finally, Digital Light Processing (DLP) technique was used to print complex structures with high resolution highlighting the great potential of these vitrimeric materials in 3D printing.Analysis of the effect of deviated modulating signal characteristics on the susceptibility of a small medical deviceBastian, Geon GeorgePinto Nunes, TiagoQuílez Figuerola, MarcosFernández Chimeno, MireyaSilva Martínez, Fernandohttp://hdl.handle.net/2117/4048082024-03-18T11:34:20Z2024-03-18T11:25:43ZAnalysis of the effect of deviated modulating signal characteristics on the susceptibility of a small medical device
Bastian, Geon George; Pinto Nunes, Tiago; Quílez Figuerola, Marcos; Fernández Chimeno, Mireya; Silva Martínez, Fernando
A variety of modulation techniques using various signal characteristics are used by the telecommunication industry in real-life applications. Despite this, the radiated immunity test based on the IEC 61000-4-3 only modulates in amplitude the carrier signal using a 1 kHz sine wave at 80% depth. In this study, we performed the radiated immunity test on a miniaturized device with biomedical applications using deviated signal-modulating characteristics than those mentioned in the IEC 61000-4-3. The results show that it is important to carry out an adequate risk analysis of the equipment under test (EUT) considering its unique functional characteristics before resorting to just the modulating frequency mentioned in the standards.
2024-03-18T11:25:43ZBastian, Geon GeorgePinto Nunes, TiagoQuílez Figuerola, MarcosFernández Chimeno, MireyaSilva Martínez, FernandoA variety of modulation techniques using various signal characteristics are used by the telecommunication industry in real-life applications. Despite this, the radiated immunity test based on the IEC 61000-4-3 only modulates in amplitude the carrier signal using a 1 kHz sine wave at 80% depth. In this study, we performed the radiated immunity test on a miniaturized device with biomedical applications using deviated signal-modulating characteristics than those mentioned in the IEC 61000-4-3. The results show that it is important to carry out an adequate risk analysis of the equipment under test (EUT) considering its unique functional characteristics before resorting to just the modulating frequency mentioned in the standards.Addressing scalability for real-time multiuser holo-portation: introducing and assessing a Multipoint Control Unit (MCU) for volumetric videoFernández Langa, SergiMontagud Climent, MarioRincón Rivera, DavidMoragues, JaumeCernigliaro, Gianlucahttp://hdl.handle.net/2117/4048052024-03-18T11:27:09Z2024-03-18T11:18:57ZAddressing scalability for real-time multiuser holo-portation: introducing and assessing a Multipoint Control Unit (MCU) for volumetric video
Fernández Langa, Sergi; Montagud Climent, Mario; Rincón Rivera, David; Moragues, Jaume; Cernigliaro, Gianluca
Scalability, interoperability, and cost efficiency are key remaining challenges to successfully providing real-time holo-portation (and Metaverse-like) services. This paper, for the first time, presents the design and integration of a Multipoint Control Unit (MCU) in a pioneering real-time holo-portation platform, supporting realistic and volumetric user representations (i.e., 3D holograms), with the aim of overcoming such challenges. The feasibility and implications of adopting such an MCU, in comparison with state-of-the-art architectural approaches, are assessed through experimentation in two different deployment setups, by iteratively increasing the number of concurrent users in shared sessions. The obtained results are promising, as it is empirically proved that the newly adopted stream multiplexing together with the novel per-client and per-frame Volumetric Video (VV) processing optimization features provided by the MCU allow increasing the number of concurrent users, while: (i) significantly reducing resources consumption metrics (e.g., CPU, GPU, bandwidth) and frame rate degradation on the client side; and (ii) keeping the end-to-end latency within acceptable limits.
2024-03-18T11:18:57ZFernández Langa, SergiMontagud Climent, MarioRincón Rivera, DavidMoragues, JaumeCernigliaro, GianlucaScalability, interoperability, and cost efficiency are key remaining challenges to successfully providing real-time holo-portation (and Metaverse-like) services. This paper, for the first time, presents the design and integration of a Multipoint Control Unit (MCU) in a pioneering real-time holo-portation platform, supporting realistic and volumetric user representations (i.e., 3D holograms), with the aim of overcoming such challenges. The feasibility and implications of adopting such an MCU, in comparison with state-of-the-art architectural approaches, are assessed through experimentation in two different deployment setups, by iteratively increasing the number of concurrent users in shared sessions. The obtained results are promising, as it is empirically proved that the newly adopted stream multiplexing together with the novel per-client and per-frame Volumetric Video (VV) processing optimization features provided by the MCU allow increasing the number of concurrent users, while: (i) significantly reducing resources consumption metrics (e.g., CPU, GPU, bandwidth) and frame rate degradation on the client side; and (ii) keeping the end-to-end latency within acceptable limits.Eugenol-based dual-cured materials with multiple dynamic exchangeable bondsRoig Gibert, AdriáRamis Juan, XavierDe la Flor López, SilviaSerra Albet, Maria Àngelshttp://hdl.handle.net/2117/4048022024-03-18T11:10:14Z2024-03-18T11:08:19ZEugenol-based dual-cured materials with multiple dynamic exchangeable bonds
Roig Gibert, Adriá; Ramis Juan, Xavier; De la Flor López, Silvia; Serra Albet, Maria Àngels
In the present work, the preparation of sustainable thermosets has been approached simultaneously from three different points of view: a) the use of bio-based monomers chemically modified through green methodologies, b) the adoption of dual curing through click-type reactions to implement more efficient manufacturing processes, and c) inclusion of interchangeable groups in the network, to enable the reuse and recycling of the material at the end of its useful life and avoid waste generation. The first goal has been approached by synthesizing in a greener way an acrylate-epoxy derivative of eugenol (AEEU) and a glycerol triacrylate (GTA), both biobased resources. Then, the second approach was addressed by using biobased cystamine as a crosslinker to obtain materials through a dual-curing procedure based on a first “click” aza-Michael reaction and a second “click” epoxy-amine reaction. Intermediate and final materials could be prepared with different tailorable properties by controlling the molar ratio of the AEEU and GTA. By using DSC and rheology, we could evaluate the sequentiality and the gelation of the curing process. Finally, the covalent adaptable networks (CANs) prepared contained three different types of dynamic bonds (disulfide, esters, and ß-aminoesters) and their thermomechanical properties were tested by DMA revealing Tgs above room temperature from 47 to 70 °C. Bending tests at break were performed to evaluate the mechanical properties reaching values up to 90 MPa of stress at break and 7 % of deformation. Stress relaxation tests showed that all materials could relax the stress at relatively low temperatures (120 °C) in less than 21 min. The associative and dissociative behavior of these materials was investigated through rheology revealing a clear drop of the modulus at high temperatures and frequencies when cystamine was used as a crosslinker. Moreover, their reprocessability was tested obtaining homogeneous samples with no significant changes in their chemical and thermal properties highlighting the great potential and wide range of possibilities in many different fields of these CANs.
2024-03-18T11:08:19ZRoig Gibert, AdriáRamis Juan, XavierDe la Flor López, SilviaSerra Albet, Maria ÀngelsIn the present work, the preparation of sustainable thermosets has been approached simultaneously from three different points of view: a) the use of bio-based monomers chemically modified through green methodologies, b) the adoption of dual curing through click-type reactions to implement more efficient manufacturing processes, and c) inclusion of interchangeable groups in the network, to enable the reuse and recycling of the material at the end of its useful life and avoid waste generation. The first goal has been approached by synthesizing in a greener way an acrylate-epoxy derivative of eugenol (AEEU) and a glycerol triacrylate (GTA), both biobased resources. Then, the second approach was addressed by using biobased cystamine as a crosslinker to obtain materials through a dual-curing procedure based on a first “click” aza-Michael reaction and a second “click” epoxy-amine reaction. Intermediate and final materials could be prepared with different tailorable properties by controlling the molar ratio of the AEEU and GTA. By using DSC and rheology, we could evaluate the sequentiality and the gelation of the curing process. Finally, the covalent adaptable networks (CANs) prepared contained three different types of dynamic bonds (disulfide, esters, and ß-aminoesters) and their thermomechanical properties were tested by DMA revealing Tgs above room temperature from 47 to 70 °C. Bending tests at break were performed to evaluate the mechanical properties reaching values up to 90 MPa of stress at break and 7 % of deformation. Stress relaxation tests showed that all materials could relax the stress at relatively low temperatures (120 °C) in less than 21 min. The associative and dissociative behavior of these materials was investigated through rheology revealing a clear drop of the modulus at high temperatures and frequencies when cystamine was used as a crosslinker. Moreover, their reprocessability was tested obtaining homogeneous samples with no significant changes in their chemical and thermal properties highlighting the great potential and wide range of possibilities in many different fields of these CANs.