Toughening and healing of continuous fibre reinforced composites by supramolecular polymers

\u3cp\u3eInterleaves comprising self-healing materials based on hydrogen bonded supramolecular polymers (SP) were successfully incorporated in the mid-plane of unidirectional (UD) carbon fibre reinforced polymers (CFRPs). The fracture toughness of these hybrid composites and their healing capability were measured under mode I loading. The fracture toughness appeared to have increased considerably since the maximum load (P\u3csub\u3emax\u3c/sub\u3e) of the hybrid composite had increased approximately 5 times, and the fracture energy I (G\u3csub\u3eIC\u3c/sub\u3e) displayed a dramatic increase by almost one order of magnitude when compared to the reference composite without the SP. Furthermore, the double cantilever beam (DCB) hybrid composites displayed a healing efficiency (H.E.) value for the mode I interlaminar characteristics around 60% for the P\u3csub\u3emax\u3c/sub\u3e and the G\u3csub\u3eIC\u3c/sub\u3e after the first healing cycle, dropping to 20-30% after the seventh cycle. During the mode I interlaminar fracture toughness tests the acoustic emission (AE) activity of the samples was also monitored. It was found that AE-activity strongly reduced due to the presence of the SP. Moreover, optical microscopy not only showed that the epoxy matrix at the interface is partly infiltrated by the SP, but it also revealed that cross-sections of both fractured surfaces were covered with the SP comprising pulled-out carbon fibres, indicating a strong interfacial adhesion. Finally it was shown that the SP fractured surfaces were partially covered with pulled-out carbon fibres emanating from the edges of the SP film in which the epoxy system exists.\u3c/p\u3

Toughening and healing of continuous fibre reinforced composites by supramolecular polymers

Interleaves comprising self-healing materials based on hydrogen bonded supramolecular polymers (SP) were successfully incorporated in the mid-plane of unidirectional (UD) carbon fibre reinforced polymers (CFRPs). The fracture toughness of these hybrid composites and their healing capability were measured under mode I loading. The fracture toughness appeared to have increased considerably since the maximum load (Pmax) of the hybrid composite had increased approximately 5 times, and the fracture energy I (GIC) displayed a dramatic increase by almost one order of magnitude when compared to the reference composite without the SP. Furthermore, the double cantilever beam (DCB) hybrid composites displayed a healing efficiency (H.E.) value for the mode I interlaminar characteristics around 60% for the Pmax and the GIC after the first healing cycle, dropping to 20-30% after the seventh cycle. During the mode I interlaminar fracture toughness tests the acoustic emission (AE) activity of the samples was also monitored. It was found that AE-activity strongly reduced due to the presence of the SP. Moreover, optical microscopy not only showed that the epoxy matrix at the interface is partly infiltrated by the SP, but it also revealed that cross-sections of both fractured surfaces were covered with the SP comprising pulled-out carbon fibres, indicating a strong interfacial adhesion. Finally it was shown that the SP fractured surfaces were partially covered with pulled-out carbon fibres emanating from the edges of the SP film in which the epoxy system exists

Terminal Terrestre Yerbateros como regenerador urbano

Elabora una investigación en torno al transporte terrestre interprovincial que llega y sale de Lima, que permita diseñar un terminal con la capacidad de descongestionar la zona intervenida, mediante el agrupamiento de empresas transportistas y el ordenamiento de sus flujos vehiculares. Además, se busca comprender las necesidades básicas para garantizar el buen funcionamiento del terminal y su activación mediante la implementación de características intermodales y usos complementarios. Finalmente, se analizarán las condicionantes y problemáticas de la zona para comprender la posibilidad de regeneración y beneficios que brindaría un diseño enfocado hacia el peatón mediante la implementación de espacio público

Mode II fracture toughening and healing of composites using supramolecular polymer interlayers

This study focuses on the transfer of the healing functionality of supramolecular polymers (SP) to fibre reinforced composites through interleaving. SPs exhibiting self-healing based on hydrogen bonds were formed into films and were successfully incorporated into carbon fibre composites. The effect of the SP interleaves on in-plane fracture toughness and the subsequent healing capability of the hybrid composites were investigated under mode II fracture loading. The fracture toughness showed considerable increase since the maximum load (P max ) of the hybrid composite approximately doubled, and consequently the mode II interlaminar fracture toughness energy (G IIC ) exhibited an increase reaching nearly 100% compared to the reference composite. The healing component was activated using external heat. P max and G IIC recovery after activation were measured, exhibiting a healing efficiency after the first healing cycle close to 85% for P max and 100% for G IIC , eventually dropping to 80% for P max while G IIC was retained around 100% even after the fourth healing cycle. Acoustic Emission activity during the tests was monitored and was found to be strongly reduced due to the presence of the SP

Sustainable Development Approaches through Wooden Adhesive Joints Design

Over recent decades, the need to comply with environmental standards has become a concern in many industrial sectors. As a result, manufacturers have increased their use of eco-friendly, recycled, recyclable, and, overall, more sustainable materials and industrial techniques. One technique highly dependent on petroleum-based products, and at the edge of a paradigm change, is adhesive bonding. Adhesive bonding is often used to join composite materials and depends upon an adhesive to achieve the connection. However, the matrices of the composite materials and the adhesives used, as well as, in some cases, the composite fibres, are manufactured from petrochemical products. Efforts to use natural composites and adhesives are therefore ongoing. One composite that has proven to be promising is wood due to its high strength and stiffness (particularly when it is densified), formability, and durability. However, wood must be very carefully characterised since its properties can be variable, depending on the slope of the grains, irregularities (such as knots, shakes, or splits), and on the location and climate of each individual tree. Therefore, in addition to neat wood, wood composites may also be a promising option to increase sustainability, with more predictable properties. To bond wood or wooden composite substrates, bio-adhesives can be considered. These adhesives are now formulated with increasingly enhanced mechanical properties and are becoming promising alternatives at the structural application level. In this paper, wooden adhesive joints are surveyed considering bio-adhesives and wood-based substrates, taking into consideration the recent approaches to improve these base materials, accurately characterise them, and implement them in adhesive joints

Characteristics of Long-Term Survival in Patients With Myelodysplastic Syndrome Treated With 5-Azacyditine: Results From the Hellenic 5-Azacytidine Registry

Background: Hypomethylating agents have altered the prognosis of myelodysplastic syndrome (MDS) so that long-term survival is now a feasible treatment goal. Patients and Methods: We analyzed data from patients with MDS treated with 5-azacytidine recorded in the Hellenic 5-azacytidine registry. We divided patients, on the basis of their survival after 5-azacytidine initiation (OST), in groups of long-term survivors (Q3 and P90 group with OST above the third quartile and the 90th percentile of the whole group, respectively) and short-term survivors comprising the remaining patients, and compared the characteristics between the groups. The study included 626 patients, 157 in the Q3 group and 63 in the P90 group. Results: Categorization per the International Prognostic Scoring System (IPSS), revised IPSS (IPSS-R), and World Health Organization–based prognostic scoring system (WPSS) was found to predict long-term survival, while multivariate analysis revealed that response to 5-azacytidine was the strongest predictor of long-term survival. Nevertheless, patients with hematologic improvement (HI) and stable disease (SD) were equally distributed in the groups of short- and long-term survival. Conclusion: SD should not be considered a poor treatment response and should not be grouped with failure, while HI offers similar prognosis to SD and thus should not be grouped with complete and partial remission. Patients with SD should continue treatment with 5-azacytidine. The prognosis of myelodysplastic syndrome (MDS) has changed since the introduction of hypomethylating agents that offer the potential for long-term survival. We studied the characteristics of long-term survival in a cohort of 626 patients with MDS treated with 5-azacytidine; response was found to be the single most important predictive factor of long-term survival, while stable disease (SD) and hematologic improvement were equally distributed in the groups with long- and short-term survival. Achieving SD has prognostic significance, and SD should not be grouped with treatment failure. © 2019 Elsevier Inc

Characteristics of Long-Term Survival in Patients With Myelodysplastic Syndrome Treated With 5-Azacyditine: Results From the Hellenic 5-Azacytidine Registry

Background: Hypomethylating agents have altered the prognosis of myelodysplastic syndrome (MDS) so that long-term survival is now a feasible treatment goal. Patients and Methods: We analyzed data from patients with MDS treated with 5-azacytidine recorded in the Hellenic 5-azacytidine registry. We divided patients, on the basis of their survival after 5-azacytidine initiation (OST), in groups of long-term survivors (Q3 and P90 group with OST above the third quartile and the 90th percentile of the whole group, respectively) and short-term survivors comprising the remaining patients, and compared the characteristics between the groups. The study included 626 patients, 157 in the Q3 group and 63 in the P90 group. Results: Categorization per the International Prognostic Scoring System (IPSS), revised IPSS (IPSS-R), and World Health Organization–based prognostic scoring system (WPSS) was found to predict long-term survival, while multivariate analysis revealed that response to 5-azacytidine was the strongest predictor of long-term survival. Nevertheless, patients with hematologic improvement (HI) and stable disease (SD) were equally distributed in the groups of short- and long-term survival. Conclusion: SD should not be considered a poor treatment response and should not be grouped with failure, while HI offers similar prognosis to SD and thus should not be grouped with complete and partial remission. Patients with SD should continue treatment with 5-azacytidine. The prognosis of myelodysplastic syndrome (MDS) has changed since the introduction of hypomethylating agents that offer the potential for long-term survival. We studied the characteristics of long-term survival in a cohort of 626 patients with MDS treated with 5-azacytidine; response was found to be the single most important predictive factor of long-term survival, while stable disease (SD) and hematologic improvement were equally distributed in the groups with long- and short-term survival. Achieving SD has prognostic significance, and SD should not be grouped with treatment failure. © 2019 Elsevier Inc

Estimated glomerular filtration rate independently predicts outcome of azacitidine therapy in higher-risk Myelodysplastic syndromes. Results from 536 patients of the Hellenic National Registry of Myelodysplastic and Hypoplastic syndromes

Higher-risk Myelodysplastic syndromes (MDS) patients undergoing treatment with 5-azacytidine (AZA) are typically elderly with several comorbidities. However, the effect of comorbidities on the effectiveness and safety of AZA in real-world settings remains unclear. We analyzed data from 536 AZA-treated patients with higher-risk MDS, Myelodysplastic/Myeloproliferative neoplasms and low blast count Acute Myeloid Leukemia enrolled to the Hellenic National Registry of Myelodysplastic and Hypoplastic Syndromes. Multivariate analysis adjusted also for the International Prognostic Scoring System (IPSS), its revised version (IPSS-R) and the French Prognostic Scoring System (FPSS), demonstrated independent associations of overall and leukemia-free survival with estimated glomerular filtration rate (eGFR) <45 mL min−1/1.73 m2 (P =.039, P =.023, respectively), ECOG performance status <2 (P =.015, P =.006), and presence of peripheral blood blasts (P =.008, P =.034), while secondary MDS also correlated with significantly shorter leukemia-free survival (P =.039). Addition of eGFR <45 mL min−1/1.73 m2, in IPSS-R and FPSS increased the predictive power of both models. Only FPSS ≤2 and eGFR <45 mL min−1/1.73 m2 predicted worse response to AZA in multivariate analysis, whereas eGFR <45 mL min−1/1.73 m2 correlated significantly with death from hemorrhage (P =.003) and cardiovascular complications (P =.006). In conclusion, in the second largest real-world series of AZA-treated MDS patients, we show that an eGFR <45 mL min−1/1.73 m2 is an independent predictor of worse response and survival. This higher cut-off, instead of the commonly used serum creatinine >2 mg/dL, can be utilized as a more precise indicator of renal comorbidity during AZA therapy. Incorporation of eGFR in the prognostic assessment of AZA-treated MDS patients may prove useful not only in routine practice, but also for the appropriate patient stratification in clinical trials with AZA combinations. © 2020 John Wiley & Sons Lt