Search results for "Heat treatment"

Hot dips and high temperature conditioning to improve shelf quality of late-crop cactus pear fruit (Opuntia ficus-indica L. Mill.)

1996

An innovative route to prepare in situ graded crosslinked PVA graphene electrospun mats for drug release

2022

We present a fast, one step method to obtain PVA/graphene/chlorhexidine nanofibrous membranes, with a crosslinking gradient along their cross-section. Briefly, polymeric solutions were electrospun onto a heated plate, enabling the in situ crosslinking of PVA macromolecules. Of course, the crosslinking degree of such structures was found to decrease upon the distance from the plate during deposition. The outcomes reveal the crucial role of graphene, capable of promoting heat transfer throughout the entire structure, thus leading to 70-80% crosslinking degrees and preventing delamination issues. Such membranes were compared to untreated and oven thermally treated ones, and a robust relationsh…

Behavior of carbohydrate-based material in black liquor during heating

2004

One industrial softwood Kraft black liquor was heat-treated (at 175 ?C and 190 ?C for 15-60 min) together with laboratory-made soda-AQ (wheat straw and reed canary grass) and Kraft (reed canary grass) black liquors (at 190 ?C for 30 min). The feedstock black liquors were characterized with respect to their polysaccharide (mainly xylem) and aliphatic carboxylic acid contents before and after the heat treatments. It was noted that, due to the higher amount of polysaccharides in the non-wood black liquors (8.2-16.6% of d.s) compared to that in the softwood black liquor (1.4% of d.s), the heat treatment in the former case resulted in a 5-30% increase in the amount of aliphatic acids formed by v…

Optical and morphological properties of infrared emitting functionalized silica nanoparticles

2013

Abstract The loading process of functionalized silica nanoparticles was investigated in order to obtain nanoparticles having functional groups on their surface and Near-Infrared (NIR) emission properties. The NIR emission induced by O 2 loading was studied in silica nanoparticles, produced by pyrogenic and microemulsion methods, with size ranging from 20 to 120 nm. Loading was carried out by thermal treatments in O 2 atmosphere up to 400 °C and 90 bar. The effects of the thermal treatments on the NIR emission and on the structural properties were studied by luminescence and Raman techniques, whereas the morphological features were investigated by Transmission Electron Microscopy and Atomic …

Isomerization and increase in the antioxidant properties of lycopene from Momordica cochinchinensis (gac) by moderate heat treatment with UV-Vis spec…

2014

International audience; Momordica cochinchinensis (gac) is a plant rich in lycopene. This pigment tends to solubilize in oil and get damaged during extraction. The impact of heating on cis-isomerization of oil-free lycopene in hexane was studied at 50 and 80°C during 240min with UV-Vis spectrometry, DAD-HPLC and TEAC test. The initial all-trans-form isomerized to the 13-cis isomer more rapidly at 80°C. After this treatment, 16% of the lycopene compounds were in the 9-cis-form. This isomer triggered an increase in the antioxidant properties which was detectable from concentrations above 9% and resulted in a change from 2.4 to 3.7μmol Trolox equivalent. It is thus possible to increase the bio…

Formation of nanosized strontium substituted hydroxyapatites

2012

Incorporation of specific elements into calcium phosphates offers the combination of a bioactive material and a therapeutic effect. This is important for improving the integration of implants as well as treating medical conditions. Strontium is a suitable candidate and displays the ability to stimulate bone growth and reducing bone resorption. This study investigated the formation of strontium carbonated hydroxyapatite nanoparticles from an amorphous phase. Crystallization of carbonated hydroxyapatite occurred at 585 o C, but samples with an intended 25% and 75% replacement of calcium with strontium crystallized at 624 o C. Heat treatment at the crystallization temperature revealed that str…

In-process heat treatments to improve FS-welded butt joints

2008

Friction-stir welding (FSW) is a relatively new but already well known solid-state welding process whose main advantage with respect to fusion welding processes is the possibility to successfully weld light alloys, traditionally considered difficult to weld or unweldable. Despite the good mechanical performances that can be obtained, there exists the possibility to further improve the joints' effectiveness through post-welding heat treatments that are however time and cost-expensive and, therefore, not best suited for industrial applications. In the present paper, the authors report the results of an experimental campaign, developed on FSW of AA7075-T6 aluminum alloy, aimed to investigate t…

The production of an infant formula with a minimally processed route impacts its nutritional, physiological and sensorial qualities

2021

International audience

Characterization of renewable reductants and charcoal-based pellets for the use in ferroalloy industries

2018

This study investigates the effect of high-temperature pyrolysis and post-treatment processes on spruce and oak charcoal yields and CO2 reactivity in a slow pyrolysis reactor. Post-treatment processes such as co-pyrolysis of biomass and recirculated tar mixture with that to the distillation of the charcoal-tar blend gave similar increase in charcoal yields. From a technological standpoint, co-pyrolysis of charcoal and tar mixture decreased the CO2 reactivity of the charcoal approaching that of fossil-based coke. This emphasize the importance of tar addition and high temperature treatment on charcoal properties. Moreover, the findings of this work show the potential use of the tar organic fr…

Cutting efficiency of heat-treated nickel-titanium single-file systems at different incidence angles.

2020

Cutting efficiency of Reciproc R25 (REC) and Reciproc blue R25 (REB) at different inclinations was evaluated. Sixty new files were tested at 90°, 70° and 45° of inclination in relation to the sample (n = 10), using a customised machine. All files were activated in reciprocation against standardised gypsum blocks for 120 s. Cutting efficiency was determined by measuring the block weight loss with an analytical balance and measuring the length of the block surface cut using a digital calliper. Data were statistically analysed (two-way ANOVA, Bonferroni t-test) with the significance level set at P < 0.05. There was no difference for REC among the tested angles. REB had no statistical differenc…