Search results for "Fibre"
showing 10 items of 494 documents
Chemical-physical and nutritional characteristics of mature-green and mature-ripe ‘Kensington Pride’ mango fruit cultivated in Mediterranean area dur…
2017
Introduction - Mango is a very short postharvest life climacteric fruit. Mangoes are usually harvested firm and green because they are often assigned to long transportation before reaching the market, or they are collected after color break for local markets. In both cases, temperature control is the most critical factor in fruit ripening management. The aim of this study was to investigate the quality evolution of mature-green and mature-ripe mango fruit submitted to 8°C and 90 ± 5% of relative humidity to assess the possibility to prolong its postharvest life. Materials and methods - The fruit of mango (Mangifera indica L. cv. Kensington Pride) grown in a Mediterranean environment was s…
GIUNZIONI BULLONATE FRA COMPOSITO E ALLUMINIO: STUDIO DEL GIOCO MEDIANTE FIBRE OTTICHE INGLOBATE NELLO SPESSORE
2010
Le giunzioni bullonate di elementi in composito sono state da sempre utilizzate per applicazioni impegnative. Sono stati annegati estensimetri a fibra ottica nello spessore di un pannello in composito in prossimità della superficie di contatto piastra-bullone in un giunto ibrido composito-alluminio. Sono state eseguite diverse prove di trazione su provini single-lap joint con differenti valori del gioco tra bullone e foro. Le prove consentono di determinare una relazione fra il gioco tra bullone e foro e i valori delle deformazioni misurate dagli estensimetri a fibra ottica. Risulta che ad un incremento dei valori del gioco corrisponde un incremento dei valori di deformazione in prossimità …
Matériaux composites soumis à de grandes vitesses de sollicitation
2006
International audience; L'objet de ce travail est de modéliser la réponse à des sollicitations quasi-statiques et dynamiques de deux matériaux composites utilisés dans l'industrie automobile : un tissu verre/polypropylène et une matrice polypropylène renforcée de fibres courtes en verre. Pour ce faire, des essais mécaniques à différentes vitesses de sollicitation (de 10-4s-1 à 100s-1 ) ont été menés. La campagne expérimentale nous a permis d'identifier pour chacun des matériaux les phénomènes dissipatifs prépondérants et de quantifier leur part dans la déformation totale, en fonction de la vitesse. Nous proposons ensuite un modèle unifié de comportement permettant de répondre de manière coh…
COMPARISON OF CRIMSON FOUNTAINGRASS AND DISS FIBRES AS AGGREGATES FOR CEMENT MORTARS
2019
The use of natural fibres in cement composites is an expanding research field as their use can improve the mechanical and thermal behavior of cement mortars and reduce their carbon footprint. In this paper two different wild grasses, i.e. Pennisetum Setaceum, also known as crimson fountaingrass, and Ampelodesmos Mauritanicus, also called diss, are used as source of natural fibres for cement mortars. The principal aim is to evaluate the possibility of using the more invasive crimson fountaingrass in place of diss inside cement based vegetable concrete. The two plants’ fibres have been characterized by means of electron microscopy, helium picnometry; moreover, the thermal conductivity of fibr…
Study of new tellurite glasses in the TeO2-ZnO-La2O3 (TZL) system for the manufacturing of mid-infrared multimaterial optical fibers and specialty op…
2023
This thesis work was carried out using tellurite glasses from the TeO2-ZnO-La2O3 (TZL) ternary diagram for optical fibers manufacturing. The choice to use this system is motivated by the ambition to improve the transmission of optical signals within oxide glasses for which absorption bands related to OH groups are present in the transparency window. A structural study is first carried out on these glasses by Raman spectroscopy in order to understand the influence of the composition on physicochemical properties (especially on optical and thermal properties) but also to estimate the ability of a vitreous matrix to reorganize when subjected to a thermal solicitation such as the preform-to-fib…
Mechanical properties of carbon nanotube fibres: St Venant’s principle at the limit and the role of imperfections
2015
Abstract Carbon nanotube (CNT) fibres, especially if perfect in terms of their purity and alignment, are extremely anisotropic. With their high axial strength but ready slippage between the CNTs, there is utmost difficulty in transferring uniformly any applied force. Finite element analysis is used to predict the stress distribution in CNT fibres loaded by grips attached to their surface, along with the resulting tensile stress–strain curves. This study demonstrates that, in accordance with St Venant’s principle, very considerable length-to-diameter ratios (∼103) are required before the stress becomes uniform across the fibre, even at low strains. It is proposed that lack of perfect orienta…
A new multi analytical approach for the identification of synthetic and natural dyes mixtures. The case of orcein-mauveine mixture in a historical dr…
2017
In this paper, the application of a multi-analytical approach for the characterisation of synthetic and natural dyes in a historical textile is presented. The work is focused on a historical dress of a Sicilian noblewoman, dating from about 1865–1870. Firstly, SERS on fibre was performed, in order to individuate the classes of dyes employed. The SERS spectra suggested the presence of two main dyes: mauveine and orcein. In order to confirm these preliminary results, two different extraction protocols were applied. The extracts obtained were analysed by ESI-MS, MALDI-ToF and UHPCL-MS analyses, confirming the SERS results. In particular, the application of the ammonia mild extraction technique…
Sub-critical filtration conditions of commercial hollow-fibre membranes in a submerged anaerobic MBR (HF-SAnMBR) system: The effect of gas sparging i…
2012
A submerged anaerobic MBR demonstration plant with two commercial hollow-fibre ultrafiltration systems (PURON®, Koch Membrane Systems, PUR-PSH31) was operated using municipal wastewater at high levels of mixed liquor total solids (MLTS) (above 22gL -1). A modified flux-step method was applied to assess the critical flux (J C) at different gas sparging intensities. The results showed a linear dependency between J C and the specific gas demand per unit of membrane area (SGD m). J C ranged from 12 to 19LMH at SGD m values of between 0.17 and 0.5Nm 3h -1m -2, which are quite low in comparison to aerobic MBR. Long-term trials showed that the membranes operated steadily at fluxes close to the est…
Experimental study of the anaerobic urban wastewater treatment in a submerged hollow-fibre membrane bioreactor at pilot scale
2011
The aim of this study was to assess the effect of several operational variables on both biological and separation process performance in a submerged anaerobic membrane bioreactor pilot plant that treats urban wastewater. The pilot plant is equipped with two industrial hollow-fibre ultrafiltration membrane modules (PURON¿ Koch Membrane Systems, 30m 2 of filtration surface each). It was operated under mesophilic conditions (at 33°C), 70days of SRT, and variable HRT ranging from 20 to 6h. The effects of the influent COD/SO 4-S ratio (ranging from 2 to 12) and the MLTS concentration (ranging from 6 to 22gL -1) were also analysed. The main performance results were about 87% of COD removal, efflu…
Optimising an outdoor membrane photobioreactor for tertiary sewage treatment
2019
[EN] The operation of an outdoor membrane photobioreactor plant which treated the effluent of an anaerobic membrane bioreactor was optimised. Biomass retention times of 4.5, 6, and 9 days were tested. At a biomass retention time of 4.5 days, maximum nitrogen recovery rate:light irradiance ratios, photosynthetic efficiencies and carbon biofixations of 51.7¿±¿14.3¿mg¿N·mol¿1, 4.4¿±¿1.6% and 0.50¿±¿0.05¿kg CO2·m3influent, respectively, were attained. Minimum membrane fouling rates were achieved when operating at the shortest biomass retention time because of the lower solid concentration and the negligible amount of cyanobacteria and protozoa. Hydraulic retention times of 3.5, 2, and 1.5 days …