Novel charged black hole solutions of Born-Infeld type: General properties, Smarr formula and Quasinormal frequencies

We investigate two novel models of charged black holes in the framework of non-linear electrodynamics of Born-Infeld type. In particular, starting from two concrete Lagrangian densities, the corresponding metric potentials, the electric field, the Smarr formula and finally, the (scalar) quasinormal modes are computed for each model. Our findings show that although the models look very similar, their quasinormal spectra are characterized by certain differences.Comment: 18 pages, 7 figures, 3 tables, to be published in Annals of Physic

Direct C–H Allylation of Unactivated Alkanes by Cooperative W/Cu Photocatalysis

Here we report a photocatalytic methodology that enables the direct allylation of strong aliphatic C–H bonds with simple allylic chlorides. The method relies on a cooperative interaction of two metal catalysts in which the decatungstate anion acts as a hydrogen-atom abstractor generating a nucleophilic carbon-centered radical that engages in an SH2′ reaction with an activated allylic π-olefin–copper complex. Because of this dual catalysis, the protocol allows for the functionalization of a range of chemical feedstocks and natural products under mild conditions in short reaction timesFinancial support from the European Research Council (ERC-CoG 863914-BECAME), Agencia Estatal de Investigación (PID2020-118237RB-I00), Xunta de Galicia (ED431C 2018/04; Centro singular de investigación de Galicia accreditation 2019-2022, ED431G 2019/03), and the European Regional Development Fund (ERDF) is gratefully acknowledgedS

Feeding Habits of Dwarf Goatfish (Upeneus parvus: Mullidae) on the Continental Shelf in the Gulf of Mexico

Feeding habits of dwarf goatfish on the continental shelf off Alvarado, Veracruz, Mexico, were analyzed to determine seasonal variation and size-class changes in diet composition and trophic overlap between size classes. Food was found in 63% of the 1,437 dwarf goatfish guts analyzed. The 52 dietary items identified consisted mainly of crustaceans, with Solenocera vioscai being the most important prey. Dwarf goatfish exhibited seasonal and size-class changes in prey consumption. Despite the high number of prey items, low values of diversity and diet breadth were found in the trophic spectrum. A high trophic overlap between size classes was observed in the north-winds season between length classes (92-111 vs 112-130 mm) (λ = 0.81) and (92-111 vs 131-150 mm) (λ = 0.80), and (112-131 vs 131-150 mm) (λ = 0.67). In the rainy season high overlaps were obtained between (92-111 vs 112-131 min) (λ = 0.73) and (112-131 vs 131-150 mm) (λ = 0.84) length classes. Dwarf goatfish appear to be opportunistic carnivorous predators that impact benthic and epibenthic invertebrates

PLA films with improved flexibility properties by using maleinized cottonseed oil

[EN] This work assesses the potential of maleinized cottonseed oil MCSO as plasticizer in poly(lactic acid) PLA films with improved ductile behaviour. The effects of MCSO are compared with commercially available maleinized oil, i.e. maleinized linseed oil MLO in terms of mechanical, thermal and barrier properties, as well as morphology changes. Plasticized PLA formulations were obtained with a maleinized oil content in the 0 10 wt% range. Addition of both maleinized vegetable oils leads to a slight decrease in the glass transition temperature (Tg) of neat PLA from 63 °C to 60 61 °C. Nevertheless, MCSO provides better overall properties. Addition of 7.5 wt% MCSO increases the elongation at break by 292%. Regarding the barrier properties, both maleinized vegetable oils increase the oxygen transmission rate OTR. Nevertheless, this increase is less pronounced in the case of MCSO thus indicating its higher efficiency compared to MLO. On the other hand, addition of both maleinized vegetable oils do not compromise the overall disintegration of the obtained PLA formulations, thus positioning these additives as environmentally friendly solutions to increase ductile properties in PLA-based films.This research was supported by the Ministry of Economy and Competitiveness - MINECO, Ref: MAT2014-59242-C2-1-R. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia for financial support through an FPI grant. Garcia-Garcia wants to thanks the Spanish Ministry of Education, Culture and Sports for their financial support through an FPU grant (FPU13/06011).Carbonell-Verdu, A.; Garcia-Garcia, D.; Dominici, F.; Torre, L.; Sanchez-Nacher, L.; Balart, R. (2017). PLA films with improved flexibility properties by using maleinized cottonseed oil. European Polymer Journal. 91:248-259. https://doi.org/10.1016/j.eurpolymj.2017.04.013S2482599

Development of environmentally friendly composite matrices from epoxidized cottonseed oil

The continuous rise in oil prices has led to the use of other ways to obtain polymer materials. This paper proposes a methodology to obtain a thermosetting resin from cottonseed oil by epoxidation process. The cottonseed oil contains as most representative fatty acids: 52.5% of linoleic acid (C18: 2), 23.9% of palmitic acid (C16: 0) and 17.6% of oleic acid (C18: 1); the real iodine index, which is indicative of the number of double bonds, has a value of 107. Epoxidized cottonseed oil (ECSO) has been successfully obtained using conventional epoxidation process with hydrogen peroxide, acetic acid and sulfuric acid, maintaining a constant temperature of 70 °C with homogeneous magnetic stirring. Average oxirane oxygen content (OOC) of 5.32% can be obtained by conventional epoxidation process which represents a yield over 83%. The epoxidized oil has been crosslinked with mixtures of two cyclic anhydrides to tailor different properties on final crosslinked thermosetting resins: on the one hand, methyl nadic anhydride (MNA) which is characterized by a rigid molecular structure and on the other hand, dodecenylsuccinic anhydride (DDSA) with a long side chain that can confer flexibility. The crosslinking process has been followed by dynamic differential scanning calorimetry (DSC), ionic mobility and oscillatory rheometry (OR) as well as gel time determination. The effect of the hardener mixture (wt.% DDSA:MNA) on mechanical performance of cured materials has been followed by flexural and impact tests as well as the evolution of the storage modulus (G′) by dynamic mechanical analysis (DMA) in torsion mode. By selecting the appropriate hardener mixture, it is possible to obtain crosslinked materials with different properties ranging from stiff matrices for ECSO crosslinked with MNA to flexible matrices for ECSO cured with DDSA. This has occurred with other thermosetting resins like epoxidized soy bean oil (ESBO) or epoxidized linseed oil (ELO). (C) 2014 Elsevier Ltd. All rights reserved.Authors thank Conselleria d'Educacio, Cultura i Esport (Generalitat Valenciana) Ref: GV/2014/008 for financial support.Carbonell Verdú, A.; Bernardi, L.; García García, D.; Sánchez Nacher, L.; Balart Gimeno, RA. (2015). Development of environmentally friendly composite matrices from epoxidized cottonseed oil. European Polymer Journal. 63:1-10. doi:10.1016/j.eurpolymj.2014.11.043S1106

A comparative study on the reactive compatibilization of melt-processed polyamide 1010/polylactide blends by multi-functionalized additives derived from linseed oil and petroleum

[EN] This research work describes the manufacturing and characterization of novel engineering materials consisted of fully bio-based blends of polyamide 1010 (PA1010) with 20 wt% of polylactide (PLA). Four different compatibilizers were used to enhance the miscibility and the performance of the biopolymer blends. Two multi-functionalized vegetable oils (maleinized linseed oil (MLO) and epoxidized linseed oil (ELO)) and two petroleum-derived glycidyl-based additives (epoxy styrene-acrylic oligomer (ESAO) and styrene-glycidyl methacrylate copolymer (PS-GMA)) were tested during melt compounding. The resultant biopolymer blends were processed by either cast film extrusion or injection molding to obtain films and pieces, respectively. Thin films with an average thickness of 50¿60 µm and thick pieces of 4 mm were obtained, and their mechanical, morphological, thermal, thermomechanical, barrier and, optical properties were characterized. Although all four compatibilizers successfully provided compatibilization to the blends, the chemically modified vegetable oils, that is, MLO and ELO yielded the injection-molded pieces with the most balanced mechanical properties in terms of strength and toughness. Besides, the resultant films showed very low oxygen transmission rate values, thus broadening the potential of these biopolymer blends for the food packaging industryThis research work was funded by the Spanish Ministry of Science, Innovation, and Universities (MICIU) project numbers MAT2017-84909-C2-2-R and AGL2015-63855-C2-1-R. Quiles-Carrillo and Torres-Giner are recipients of a FPU grant (FPU15/03812) from the Spanish Ministry of Education, Culture, and Sports (MECD) and a Juan de la Cierva contract (IJCI-2016-29675) from MICIU, respectively. Microscopy services at UPV are acknowledged for their help in collecting and analyzing FESEM images. Authors thank Polyscope for kindly supplying XibondTM 920 for this study.Quiles-Carrillo, L.; Fenollar, O.; Balart, R.; Torres-Giner, S.; Rallini, M.; Dominici, F.; Torre, L. (2020). A comparative study on the reactive compatibilization of melt-processed polyamide 1010/polylactide blends by multi-functionalized additives derived from linseed oil and petroleum. eXPRESS Polymer Letters. 14(6):583-604. https://doi.org/10.3144/expresspolymlett.2020.48S58360414

Manufacturing and compatibilization of PLA/PBAT binary blends by cottonseed oil-based derivatives

[EN] This research work aims at the compatibilization of poly(lactic acid)/poly(butylene adipate-co-terephthalate), PLA/PBAT binary blends by using cottonseed oil derivatives, i.e. epoxidized (ECSO) and maleinized (MCSO) cottonseed oil. The potential of these vegetable oil-based compatibilizers are compared versus the effects of a conventional styrene-acrylic oligomer. The base PLA/PBAT binary blend composition was 80 wt% PLA/20 wt% PBAT and the amount of compatibilizer was set to 1 and 7.5 wt%. The effects of the different compatibilizers were evaluated on PLA/PBAT films in terms of mechanical and thermal properties as well as blend's morphology by field emission scanning electron microscopy (FESEM). Complementary, biodisintegration tests in controlled compost soil and surface properties were evaluated to assess the effects of the compatibilizers. Addition of 1 wt% ECSO and MCSO led to a remarkable increase in the elongation at break up to values over 100% with regard to neat PLA. Despite this, maximum elongation at break was obtained for the compatibilized PLA/PBAT blend with 7.5 wt% MCSO, reaching values of about 321.2% respect neat PLA keeping mechanical resistant properties, such as Young's modulus and tensile strength, at high levels. Therefore, vegetable oil-derived compatibilizers stand out as environmentally friendly additives for PLA/PBAT binary blends with improved properties.This work was supported by the Ministry of Economy and Competitiveness (MINECO) (grant number MAT2017-84909-C2-2-R). A. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia for financial support through an FPI grant.Carbonell-Verdu, A.; Ferri, J.; Dominici, F.; Boronat, T.; Sanchez-Nacher, L.; Balart, R.; Torre, L. (2018). Manufacturing and compatibilization of PLA/PBAT binary blends by cottonseed oil-based derivatives. eXPRESS Polymer Letters. 12(9):808-823. https://doi.org/10.3144/expresspolymlett.2018.69S80882312