6,596 research outputs found
Adding Value: Certified Coffee Trade in North America
Coffee is the leading agricultural sector in terms of both the number and frequent use of social and environmental certification. This fast-growing category of certified sustainable coffees has emerged from almost negligible quantities in the late 1990s to approximately 4% of global green coffee exports in 2006 making it a multi-billion dollar segment of the industry. The US and Canada account for over one quarter of global coffee imports in value. Their consumers are increasingly attentive to the social, economic, and environmental aspects of coffee production as evidenced by the significant expansion of certified coffees into both gourmet and mass market channels. This chapter covers the market development and current statistics of all the certified sustainable coffees in North America including volumes, value, premiums, and their general trends at the global level.organic; fair trade; eco-friendly; Rainforest Alliance; Utz; certified; coffee; commodities; supply chain; sustainable; markets
Cu@COMOC-4, a bimetallic metal-organic framework for the size selective epoxidation of cycloalkenes
Easy orientation of diblock copolymers on self-assembled monolayers using UV irradiation
A simple method based on UV/ozone treatment is proposed to control the
surface energy of dense grafted silane layers for orientating block copolymer
mesophases. Our method allows one to tune the surface energy down to a fraction
of a mN/m. We show that related to the surface, perpendicular orientation of a
lamellar phase of a PS-PMMA diblock copolymer (neutral surface) is obtained for
a critical surface energy of 23.9-25.7 mN/m. Perpendicular cylinders are
obtained for 24.6 mN/m and parallel cylinders for 26.8 mN/m.Comment: 3 figures, 1 tabl
Metal-organic frameworks as selective or chiral oxidation catalysts
Since the discovery of Metal Organic Frameworks (MOFs) in the early 1990s, the amount of new structures has grown exponentially. A MOF typically consists of inorganic nodes that are connected by organic linkers to form crystalline, highly porous structures. MOFs have attracted a lot of attention lately, as the versatile design of such materials holds promises of interesting applications in various fields. In this review, we will focus on the use of MOFs as heterogeneous oxidation catalysts. MOFs are very promising candidates to replace homogeneous catalysts by sustainable and stable heterogeneous catalysts.
The catalytic active function can be either the active metal sites of the MOF itself or can be introduced as an extra functionality in the linker, a dopant or a "ship-in-a-bottle" complex. As the pore size, pore shape, and functionality of MOFs can be designed in numerous ways, shape selectivity, and even chiral selectivity can be created. In this article, we will present an overview on the state of the art of the use of MOFs as a heterogeneous catalyst in liquid phase oxidation reactions
Modified Star-Products Beyond the Large-B Limit
Derivative corrections to the Wess--Zumino couplings of open-string effective
actions are computed at all orders in derivatives, taking the open-string
metric into account. This leads to a set of deformed star-products beyond the
Seiberg--Witten limit, and allows to reinterpret the couplings in terms of a
deformed integration prescription along a Wilson line in the non-commutative
set-up. Moreover, the recursive definition of the star-products induces
deformations of U(1) non-commutative Yang--Mills theory.Comment: 9 pages; references added; a few clarifications and a consistency
check added, version to appear in Phys. Lett.
POM@MOF hybrids : synthesis and applications
The hybrid materials that are created by supporting or incorporating polyoxometalates (POMs) into/onto metalâorganic frameworks (MOFs) have a unique set of properties. They combine the strong acidity, oxygen-rich surface, and redox capability of POMs, while overcoming their drawbacks, such as difficult handling, a low surface area, and a high solubility. MOFs are ideal hosts because of their high surface area, long-range ordered structure, and high tunability in terms of the pore size and channels. In some cases, MOFs add an extra dimension to the functionality of hybrids. This review summarizes the recent developments in the field of POM@MOF hybrids. The most common applied synthesis strategies are discussed, together with major applications, such as their use in catalysis (organocatalysis, electrocatalysis, and photocatalysis). The more than 100 papers on this topic have been systematically summarized in a handy table, which covers almost all of the work conducted in this field up to now
Design of enantioselective catalysts in MOF architectures : a combined computational and experimental approach
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