76 research outputs found
Поглощение воды и водных растворов глинополимерными нанокомпозитами внедрения
Рассмотрено первичное и повторное поглощение воды и раствора, имитирующего жидкие отходы атомных
станций, глинополимерными нанокомпозитами внедрения, синтезированными на основе бентонита. Показано,
что частицы глинополимерного нанокомпозита более эффективно поглощают воду и солевые растворы по
сравнению с частицами природного бентонита.Розглянуто первинне і повторне поглинання води і
розчину, який імітує рідкі відходи атомних станцій,
глинополімерними нанокомпозитами проникнення,
синтезованими на основі бентоніту. Показано, що частинки глинополімерного нанокомпозита ефективніше поглинають воду і сольові розчини у порівнянні з частинками природного бентоніту.In many cases the use of nanocomposites is restrained by
insufficient knowledge of their properties. It primarily
relates to intercalated nanocomposites, especially the nano
composites with particles size less than 0.6 mm, containing
a significant amount of clay (>60 %). The research
is focus on the study of the properties of such na nocomposites.
The bentonite clay from the Cherkassy deposit
comprising up to 95 % of Ca-montmorillonite was used
for the synthesis of nanocomposites. The preliminary
substitution of Na⁺ cations for Ca²⁺ and Mg²⁺ cations was
carried out. The nanocomposites clay-polymer were obtained in the process of free radical polymerization. The
nanocomposites, dried at 105 ºC with particle size of 0.4 ÷
0.6 mm were used for experiments. The properties of the nanocomposites to take up
water and solutions were studied by Enslin method. The
maximum value of water uptake was 69.45 ml/g. Subsequently,
the sample was dried on the filter to constant weight and repeated water uptake was examined. In this
case, the result was 82 ml/g, i. e. in repeated contact with
water particles absorbed by 18 % more amount water than
during first water uptake. The increase in water uptake is
due to nonuniform polymerization (in volume and time),
which resulted in deformation of some polymer chains and
only after water absorption, polymer chains have a chance
to take a more low-energy position. Since this phenomenon
was observed for particle size of less than 0.6 mm, it can
be assumed that the crystallites or aggregates of intercalated
nanocomposites clay-polymer are the sites of the beginning
of acrylamide polymerization. The rate of water re-absorption was lower than in
case of the primary water uptake up to period of time of
1000 min and was constant to 5000 min while the rate of
primary absorption decreased substantially after 1000 min.
The sorption capacity of nanocomposites for solutions
simulating waste of nuclear power plants was 18 ml/g that was higher than absorption by natural bentonite (3.4 ml/g). Thus, the intercalated nanocomposites clay-polymer
could be promising materials as components of the geochemical and water insulating barriers
Influence du procédé de dépulpage de la drupe de Coffea arabica L. sur la fermentation
Au cours du traitement de postrécolte du café Arabica, l'eau utilisée a une influence directe sur les paramètres physico-chimiques, microbiologiques et biochimiques de la fermentation. Elle intervient lors du dépulpage et du transport des drupes dépulpées jusqu'à la cuve de fermentation, solubilise alors les sucres simples du mucilage, ralentit la croissance microbienne et en conséquence l'acidification du milieu fermentaire. Le dépulpage et le transport du café avec ou sans eau ne modifient pas la composition biochimique du café vert. Par ailleurs, les propriétés organoleptiques à la tasse ont été jugées identiques. Les technologies moins polluantes, dépulpage et transport sans eau des drupes dépulpées, permettent aux producteurs de contrôler la durée et l'acidité produite. En revanche, il est nécessaire de réduire le temps de fermentation car le pH devient plus rapidement acide. Des durées prolongées pourraient provoquer des surfermentations et développer des mauvais goûts. (Résumé d'auteur
What We are Learning from National Programmes in School Health and Nutrition
International audienc
Les légumineuses, accélérateur de transition ?
Intervention lors de l'émission Web " Les légumineuses, Graines de star" organisée par la Fondation pour l'Agriculture et la Ruralité dans le Monde (FARM)Intervention lors de l'émission Web " Les légumineuses, Graines de star" organisée par la Fondation pour l'Agriculture et la Ruralité dans le Monde (FARM
Regional Policy Dialogue on the Sustainable Lifestyles for SCP with an additional focus on COVID-19 with a Focus on Food
International audienc
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