409 research outputs found
Life Cycle Assessment of a Circular Economy Process for Tray Production via Water-Based Upcycling of Vegetable Waste
With one-third of food being wasted at the various steps of the value chain, there is a large amount of biomass constantly being discarded, also wasting the resources consumed for its production. Several strategies have been proposed to use this biomass as a source of raw materials for the production of plastic alternatives, but the environmental impact parameters have rarely been estimated to understand if the proposed process provides an overall benefit. The purpose of this paper is to analyze, through an experimental laboratory campaign, the production process of a vegetable biocomposite material obtained by valorization of biomass from two sources: unsold vegetables from a wholesale market and carrot pomace obtained as a byproduct of juicing. The obtained biocomposite films were thermoformed into trays to replace the traditional plastic food containers made principally with PET. Different scenarios for the lab-scale production of trays were evaluated by testing two water-based processing methods for the two types of biomass used. In order to understand which of the four scenarios was the least impactful, the global warming potential, the cumulative energy demand, and the water scarcity index were used as indicators. Among the different lab-scale processing scenarios for the upscaling of vegetable waste, the least impactful was starting from the unsold/discarded vegetables collected at the wholesale market that were processed via water-based hydrolysis catalyzed by formic acid. Impact parameters were comparable or better than two traditional polymers (PET and HDPE) and two biopolymers (PLA and biopolymer from starch), showing that this process has excellent potential, from an environmental point of view, of substituting plastic packaging
Evaluation of Mater Bi and Polylactic Acid as materials for biodegradable innovative mini-radiosondes to track small scale fluctuations within clouds
Turbulence plays an important part in determining the chemical and physical processes, on both the micro- and macro-scales, whereby clouds are formed and behave. However, exactly how these are linked together and how turbulence impacts each of these processes is not yet fully understood. This is partly due to a lack of in-situ small scale fluctuation measurements due to a limitation in the available technology. It is in this context that the radiosondes, for which the material characterisation is presented in this paper, are being developed to generate a Lagrangian set of data which can be used to improve the ever-expanding knowledge of atmospheric processes and, in particular, the understanding of the interaction between turbulence and micro-physical phenomenologies inside clouds (www.complete-h2020network.eu). Specifically, the materials developed for the balloons are discussed in further detail within this paper. Mater Bi and polylactic acid are the two common biodegradable thermoplastics that were used initially to make the balloons. To tailor their properties, the balloons were then coated with carnauba wax blended with either pine resin or SiO2 nanoparticles. The properties such as hydrophobicity, toughness, elasticity and helium gas permeability are investigated and improved in order to keep the density of the radiosondes as constant as possible for a couple of hours. This will allow them to float inside and outside clouds on an isopycnic surface, to measure various properties such as velocity, temperature, pressure and humidity by means of solid state sensors and to transmit them to receivers on Earth. Tests have been made under a rigorous metrological approach comparing the 6 new materials with two reference balloon materials, latex and mylar. It was found that Mater Bi with the two carnauba wax coatings is the most suited though its roughness and water vapour permeability should be improved
Electrospun silk fibroin fibers for storage and controlled release of human platelet lysate
Human platelet lysate (hPL) is a pool of growth factors and cytokines able to induce regeneration of different tissues. Despite its good potentiality as therapeutic tool for regenerative medicine applications, hPL has been only moderately exploited in this field. A more widespread adoption has been limited because of its rapid degradation at room temperature that decreases its functionality. Another limiting factor for its extensive use is the difficulty of handling the hPL gels. In this work, silk fibroin-based patches were developed to address several points: improving the handling of hPL, enabling their delivery in a controlled manner and facilitating their storage by creating a device ready to use with expanded shelf life. Patches of fibroin loaded with hPL were synthesized by electrospinning to take advantage of the fibrous morphology. The release kinetics of the material was characterized and tuned through the control of fibroin crystallinity. Cell viability assays, performed with primary human dermal fibroblasts, demonstrated that fibroin is able to preserve the hPL biological activity and prolong its shelf-life. The strategy of storing and preserving small active molecules within a naturally-derived, protein-based fibrous scaffold was successfully implemented, leading to the design of a biocompatible device, which can potentially simplify the storage and the application of the hPL on a human patient, undergoing medical procedures such as surgery and wound care. Statement of Significance: Human platelets lysate (hPL) is a mixture of growth factors and cytokines able to induce the regeneration of damaged tissues. This study aims at enclosing hPL in a silk fibroin electrospun matrix to expand its utilization. Silk fibroin showed the ability to preserve the hPL activity at temperature up to 60 \ub0C and the manipulation of fibroin's crystallinity provided a tool to modulate the hPL release kinetic. This entails the possibility to fabricate the hPL silk fibroin patches in advance and store them, resulting in an easy and fast accessibility and an expanded use of hPL for wound healing
Oil removal from water oil emulsions using magnetic nanocomposite fibrous mats
Herein we present the fabrication of hydrophobic and oleophilic poly(methyl
methacrylate) based nanocomposite fibrous mats with magnetic properties, and
their utilization for oil removal from stable water oil emulsions
On a Biobased Epoxy Vitrimer from a Cardanol Derivative Prepared by a Simple Thiol-Epoxy “Click” Reaction
The development of this work lies in the relevant interest in epoxy resins, which, despite their wide use, do not meet the requirements for sustainable materials. Therefore, the proposed approach considers the need to develop environmentally friendly systems, in terms of both the starting material and the synthetic method applied as well as in terms of end-of-life. The above issues were taken into account by (i) using a monomer from renewable sources, (ii) promoting the formation of dynamic covalent bonds, allowing for material reprocessing, and (iii) evaluating the degradability of the material. Indeed, an epoxy derived from cardanol was used, which, for the first time, was applied in the development of a vitrimer system. The exploitation of a diboronic ester dithiol ([2,2′-(1,4-phenylene)-bis[4-mercaptan-1,3,2-dioxaborolane], DBEDT) as a cross-linker allowed the cross-linking reaction to be carried out without the use of solvents and catalysts through a thiol-epoxy “click” mechanism. The dynamicity of the network was demonstrated by gel fraction experiments and rheological and DMA measurements. In particular, the formation of a vitrimer was highlighted, characterized by low relaxation times (around 4 s at 70 °C) and an activation energy of ca. 48 kJ/mol. Moreover, the developed material, which is easily biodegradable in seawater, was found to show promising flame reaction behavior. Preliminary experiments demonstrated that, unlike an epoxy resin prepared from the same monomer and using a classical cross-linker, our boron-containing material exhibited no dripping under combustion conditions, a phenomenon that will allow this novel biobased system to be widely used
VARIATION OF U-MICRODISTRIBUTION IN FOSSIL HIPPARION TEETH AS A COMPLICATING FACTOR IN DATING STUDIES
Five Upper Miocene fossil Hipparion molars were studied for U-distribution by Fission Track. U-uptake has reached the whoie mass of the teeth and no saturation fronts seem to occiir in the interior layers. Mean U-concentration in dentine, cement and enamel was 157, 139 and 78 ppm, respectively. Uenamel/Uderltinr -0.5 is considerably higher than 0.1 reported in the past for Upper-Quaternary mammoth teeth. These features are disadvantageous for ESR-dafing in Hipparion enamel, although a long-lived signal (g=2.0018) is apparent. Leaching phenomena occur in the outer regions of these teeth. Inner enamel folding seems to have hindered a more uniform U-distribution in the teeth
Patterned structures of in situ size controlled CdS nanocrystals in a polymer matrix under UV irradiation.
A method of in situ formation of patterns of size controlled CdS nanocrystals in a polymer matrix by pulsed UV irradiation is presented. The films consist of Cd thiolate precursors with different carbon chain lengths embedded in TOPAS polymer matrices. Under UV irradiation the precursors are photolyzed, driving to the formation of CdS nanocrystals in the quantum size regime, with size and concentration defined by the number of incident UV pulses, while the host polymer remains macroscopically/microscopically unaffected. The emission of the formed nanocomposite materials strongly depends on the dimensions of the CdS nanocrystals, thus, their growth at the different phases of the irradiation is monitored using spatially resolved photoluminescence by means of a confocal microscope. X-ray diffraction measurements verified the existence of the CdS nanocrystals, and defined their crystal structure for all the studied cases. The results are reinforced by transmission electron microscopy. It is proved that the selection of the precursor determines the efficiency of the procedure, and the quality of the formed nanocrystals. Moreover it is demonstrated that there is the possibility of laser induced formation of well-defined patterns of CdS nanocrystals, opening up new perspectives in the development of nanodevices
Épica, crónicas y genealogías. En torno a la historicidad de la Leyenda de los infantes de Lara
[ES] Este trabajo analiza la historicidad de la narración épica conocida como Leyenda de los Infantes de Lara. Frente a la visión tradicional, que atribuía a este relato una gran fidelidad a los hechos históricos, se sugiere una imagen más compleja, que mezcla elementos nuevos y más antiguos: 1) Un posible núcleo histórico consistente en la historia de Ruy Velázquez; 2) Una parte más compacta formada por la trama de la
venganza de sangre, que enlaza la traición con la venganza de Mudarra. Frente a la idea tradicional de que la venganza es una
completa ficción elaborada mucho tiempo después, se sugiere que traición y venganza constituyen una unidad lógica, aunque no
se relacione con hechos históricos concretos. Es muy probable que el núcleo central de la leyenda, tal y como nos ha llegado, sea más bien un conjunto amplio de temas y motivos entretejidos con hechos
históricos más o menos desfigurados.
Finalmente, todas estas piezas cobran sentido en su contexto geográfico: la leyenda parece estar reflejando un
conflicto entre Lara y Salas, leído desde el punto de vista de Salas, con una clara
hostilidad hacia Lara.Peer reviewe
Electrospun fibroin/polyurethane hybrid meshes: manufacturing, characterization and potentialities as substrates for haemodialysis arteriovenous grafts
Several attempts made so far to combine silk fibroin and polyurethane, in order to prepare scaffolds encompassing the bioactivity of the former with the elasticity of the latter, suffer from critical drawbacks concerning industrial and clinical applicability (e.g., separation of phases upon processing, use of solvents unaddressed by the European Pharmacopoeia, use of degradable polyurethanes). Overcoming these limitations, in this study we report the successful blending of regenerated silk fibroin with a medical-grade, nondegradable polyurethane using formic acid and dichloromethane, and the manufacturing of hybrid, semi-degradable electrospun tubular meshes with different ratios of the two materials. Physicochemical analyses demonstrated the maintenance of the characteristic features of fibroin and polyurethane upon solubilisation, blending, electrospinning and post-processing
with ethanol or methanol. Envisioning their possible application as semi-degradable substrates for haemodialysis arteriovenous grafts, tubular meshes were further characterized, showing sub-micrometric fibrous morphologies, tuneable mechanical properties, permeability before and after puncture in the same order of magnitude as commercial grafts currently used in the clinics. Results demonstrate the potential of this material for the development of hybrid, new-generation vascular grafts with disruptive potential in the field of in situ tissue engineering
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