Search results for "Spinning"
showing 10 items of 204 documents
Preparation and characterization of PCL/GO-g-PEG biocomposite nanofiber scaffolds
2016
Biocomposite nanofiber scaffolds of polycaprolactone (PCL) with different graphene oxide surface grafted with poly(ethylene glycol) (GO-g-PEG) concentrations were prepared by electrospinning. Morphological, mechanical as well as wettability characterization were carried out. Results showed that the average diameter of PLA/GO-g-PEG electrospun nanofibers increased by increasing the filler content. GO-g-PEG enhanced the electrospun PCL hydrophilicity as well as the Young modulus, in particular at low GO-g-PEG concentrations.
The apparently anomalous effects of surfactants on interfacial tension in the IBA/water system near its upper critical solution temperature
2016
We studied the effect of anionic, cationic, and nonionic surfactants on the interfacial tension between the two phases of the isobutyric acid/water system using spinning drop tensiometry. It has been found that interfacial tension decreases with increasing concentration of the surfactant in the case of sodium dodecyl sulfate (SDS) and of dodecyltrimethylammonium chloride (DTAC). However, in the case of Triton X-100 an increase of surfactant concentration leads to an increase of the interfacial tension. Such results are consistent with the upper critical solution temperature (UCST) in the presence of these surfactants: the UCST decreases with increasing SDS and DTAC concentrations while it i…
Polybutylene Succinate Processing and Evaluation as a Micro Fibrous Graft for Tissue Engineering Applications
2022
A microfibrous tubular scaffold has been designed and fabricated by electrospinning using poly (1,4-butylene succinate) as biocompatible and biodegradable material. The scaffold morphology was optimized as a small diameter and micro-porous conduit, able to foster cell integration, adhesion, and growth while avoiding cell infiltration through the graft’s wall. Scaffold morphology and mechanical properties were explored and compared to those of native conduits. Scaffolds were then seeded with adult normal human dermal fibroblasts to evaluate cytocompatibility in vitro. Haemolytic effect was evaluated upon incubation with diluted whole blood. The scaffold showed no delamination, and mech…
Processing-property relationships of polypropylene/ciprofloxacin fibers
2015
In this work we prepared polypropylene (PP) fibers incorporating an antibiotic, i.e. ciprofloxacin (CFX), by melt spinning. In particular, PP has been compounded with CFX at different concentrations by using a counter-rotating twin screw compounder. The PP/CFX fibers have been spun by using a capillary rheometer operating under a constant extrusion speed. The effect of “online” hot drawing during the melt spinning or of an “offline” cold drawing on the properties of PP/CFX fibers were evaluated. In particular, the influence of the drawing conditions on the mechanical properties and the release kinetics were studied. Moreover, the rheological behavior in non-isothermal elongation flow has be…
Green Data Centres integration in smart grids: New frontiers for ancillary service provision
2017
Abstract The paper presents a study, conceived within the GEYSER FP7 co-funded European research project, on the ancillary services that Green Data Centres (GDCs) can provide, focusing, in particular, on spinning reserve. More in detail, the main contribution of the paper is to show how GDCs can be involved in the secondary frequency regulation process of a smart distribution grid, for contrasting the disturbing effects of unexpected variation of the energy production. With this aim, a real data centre, owned by Engineering S.p.A., is simulated as connected to the Medium Voltage IEEE 14-bus test grid where some RES-based generators are supposed to exist. Simulations are carried out in order…
Crosslinked Sulfonated Poly(vinyl alcohol)/Graphene Oxide Electrospun Nanofibers as Polyelectrolytes
2019
[EN] Taking advantage of the high functionalization capacity of poly(vinyl alcohol) (PVA), bead-free homogeneous nanofibrous mats were produced. The addition of functional groups by means of grafting strategies such as the sulfonation and the addition of nanoparticles such as graphene oxide (GO) were considered to bring new features to PVA. Two series of sulfonated and nonsulfonated composite nanofibers, with different compositions of GO, were prepared by electrospinning. The use of sulfosuccinic acid (SSA) allowed crosslinked and functionalized mats with controlled size and morphology to be obtained. The functionalization of the main chain of the PVA and the determination of the optimum co…
Asymmetric Single Point Incremental Forming of Sheet Metal
2005
The use of computers in manufacturing has enabled the development of several new sheet metal forming processes, which are based upon older technologies. This paper describes modifications that have been made to traditional forming methods such as conventional spinning and shear forming, forming processes in which deformation is localized. Recent advances have enabled this localized deformation to be accurately controlled and studied. Current developments have been focused on forming asymmetric parts using CNC technology, without the need for costly dies. Asymmetric Incremental Sheet Forming has the potential to revolutionize sheet metal forming, making it accessible to all levels of manufac…
Fast field cycling NMR relaxometry characterization of biochars obtained from an industrial thermochemical process
2012
Biochar has unique properties which make it a powerful tool to increase soil fertility and to contribute to the decrease of the amount of atmospheric carbon dioxide through the mechanisms of C sequestration in soils. Chemical and physical biochar characteristics depend upon the technique used for its production and the biomass nature. For this reason, biochar characterization is very important in order to address its use either for agricultural or environmental purposes. Three different biochars obtained from an industrial gasification process were selected in order to establish their chemical and physical peculiarities for a possible use in agronomical practices. They were obtained by char…
Industrial Hemp Transformation for Composite Applications: Influence of Processing Parameters on the Fibre Properties
2017
The main objective of this collaborative work is to characterize the influence of the processing stages of industrial hemp on the fibre properties. Transformation processes well suited for composite reinforcing textiles are considered. The work focuses on the different stages along the transformation chain of hemp, from the straw retting to the preform manufacturing. The main highlight is the predominant influence of retting on the tensile properties of individual fibres after their mechanical extraction from the stalks. Regarding the secondary processing, different technologies such as spinning, and use of natural binder systems are also proposed to produce yarns and woven fabrics. The eff…
Etude par spectroscopies de RMN 23Na, 31P et 1H : effets de la teneur en sel (NaCl) dans des matrices alimentaires
2008
The reduction of salt (NaCl) content in food has become a matter of public health. However, the multiple functions of salt in food make the reduction of its content difficult. The aim of this work was to demonstrate the applicability of NMR innovative techniques in order to characterise the mobility of sodium ions (distinction between ‘free’ and ‘bound’ sodium), to bring a better understanding of the role of salt in the organisation of the food matrix (in particular phosphorous molecules in dairy systems) and to study impact of salt on the mobility of aroma compounds. In a first step, the 23Na NMR study of iota-carrageenan gels validated the quantification of total sodium (Single-Quantum, S…