Sustainable CO2 adsorbents prepared by coating chitosan onto mesoporous silicas for large-scale carbon capture technology

In this article, we report a new sustainable synthesis procedure for manufacturing chitosan/silica CO2 adsorbents. Chitosan is a naturally abundant material and contains amine functionality, which is essential for selective CO2 adsorptions. It is, therefore, ideally suited for manufacturing CO2 adsorbents on a large scale. By coating chitosan onto high-surface-area mesoporous silica supports, including commercial fumed silica (an economical and accessible reagent) and synthetic SBA-15 and MCF silicas, we have prepared a new family of CO2 adsorbents, which have been fully characterised with nitrogen adsorption isotherms, thermogravimetric analysis/differential scanning calorimetry, TEM, FTIR spectroscopy and Raman spectroscopy. These adsorbents have achieved a significant CO2 adsorption capacity of up to 0.98 mmol g−1 at ambient conditions (P=1 atm and T=25 °C). The materials can also be fully regenerated/recycled on demand at temperatures as low as 75 °C with a >85 % retention of the adsorption capacity after 4 cycles, which makes them promising candidates for advanced CO2 capture, storage and utilisation technology

The Spin--Symmetry of the Quark Model

Corrections to the exact heavy--quark symmetry results are expected to follow the $1/m_{Q}$ mass effect of the heavy--quark. We show, by an explicit calculation, that there is something other than the mass effect that suppresses the breaking of the spin symmetry

Preventing Discrimination and Positive Protection for Minorities : Aspects of International Law

Un pays est jugé par la façon dont il traite ses minorités, selon les paroles de Gandhi. L'auteur voit dans le respect de cette « règle de l'égalité » le symbole d'une maturité politique certaine. On n'a qu'à considérer l'histoire des guerres mondiales pour comprendre comment la façon dont on peut traiter certaines minorités peut affecter la paix des nations. L'élaboration du principe « d'autodétermination des peuples » après la guerre implique comme corollaire la protection des peuples minoritaires. Cette protection peut se faire sur deux plans, soit en cherchant à prévenir la discrimination, soit en élaborant des mesures positives de protection des minorités pour les aider à préserver leur identité. Sous quelles formes peut-on retrouver ces mesures de protection et quel en est l'impact réel, lorsqu'un pays entend davantage assimiler que protéger ses minorités. C'est à cette question que l'auteur tente de répondre

Social Sensing of Floods in the UK

"Social sensing" is a form of crowd-sourcing that involves systematic analysis of digital communications to detect real-world events. Here we consider the use of social sensing for observing natural hazards. In particular, we present a case study that uses data from a popular social media platform (Twitter) to detect and locate flood events in the UK. In order to improve data quality we apply a number of filters (timezone, simple text filters and a naive Bayes `relevance' filter) to the data. We then use place names in the user profile and message text to infer the location of the tweets. These two steps remove most of the irrelevant tweets and yield orders of magnitude more located tweets than we have by relying on geo-tagged data. We demonstrate that high resolution social sensing of floods is feasible and we can produce high-quality historical and real-time maps of floods using Twitter.Comment: 24 pages, 6 figure

Humphrey Center News: Spring 1990 v. 5, no. 1

Newsletter of the Hubert H. Humphrey Cancer Research Center at Boston University School of Medicine