Future proofing

Drastic improvements in growing technology in the Netherlands have achieved a large reduction in energy use and a striking increase in production

The hydrogenation of nitrobenzene over metal catalysts

The catalytic hydrogenation of nitrobenzene is an industrially important reaction used in the commercial production of aniline for use in the polyurethane industry. A mechanism for the reaction was first proposed by Haber in 1898 and has been widely accepted despite never being fully delineated. During this study the nitrobenzene hydrogenation reaction was investigated, over a range of metal catalysts, to probe the mechanism of hydrogenation and catalyst deactivation. Initial investigations over Pd/C catalysts revealed the reaction to be sensitive to the solvent and the nature of the carbon support. However more importantly it was shown that the first intermediate in Haber’s scheme, nitrosobenzene, could not act as an intermediate to nitrobenzene hydrogenation. As a result, a new reaction mechanism was proposed where the hydrogenation of nitrobenzene and nitrosobenzene proceed via separate mechanistic routes, linked by a common adsorbed intermediate; the surface concentration of this adsorbed species controls the hydrogenation pathway followed. Further investigation over Raney nickel suggests this mechanism to be valid over other metals and not specific to palladium. A series of novel bimetallic catalysts were also prepared for use in this study. Characterisation of these catalysts was carried out to determine the nature of the metal-metal interaction on the surface. the evidence suggests mixed metal particles may have been formed on some catalysts. The activity of these catalysts was found to be greatly enhanced following pre-treatment with water vapour in a hydrogen atmosphere. It was postulated that partial oxidation of the metal active sites was occurring and that these systems were more active due to the enhanced adsorption of nitrobenzene. The copper nickel/systems were found to show enhanced catalytic activity, whereas all systems containing cobalt displayed irreversible deactivation following water treatment, which was attributed to the formation of irreducible cobalt aluminium spinel from the CoO formed on the surface

Comparison of climate and production in closed, semi-closed and open greenhouses

A (semi-)closed greenhouse is a novel greenhouse with an active cooling system and temporary heat storage in an aquifer. Air is cooled, heated and dehumidified by air treatment units. Climate in (semi-)closed greenhouses differs from that of conventional open greenhouses. The aims of our research were first, to analyze the effect of active cooling on greenhouse climate, in terms of stability, gradient and average levels; second, to determine crop growth and production in closed and semi-closed greenhouses. An experiment with tomato crop was conducted from December 2007 until November 2008 in a closed greenhouse with 700 W m-2 cooling capacity, two semi-closed greenhouses with 350 and 150 W m-2 cooling capacity, respectively, and an open greenhouse. The higher the cooling capacity, the more independent the greenhouse climate was of the outside climate. As the cooling ducts were placed underneath the plants, cooling led to a remarkable vertical temperature gradient. Under sunny conditions temperature could be 5°C higher at the top than at the bottom of the canopy in the closed greenhouse. Cumulative production in the semi-closed greenhouses with 350 and 150 W m-2 cooling capacity were 10% (61 kg m-2) and 6% (59 kg m-2) higher than that in the open greenhouse (55 kg m-2), respectively. Cumulative production in the closed greenhouse was 14% higher than in the open greenhouse in week 29 after planting but at the end of the experiment the cumulative increase was only 4% due to botrytis. Model calculations showed that the production increase in the closed and semi-closed greenhouses was explained by higher CO2 concentratio

First-Order Provenance Games

We propose a new model of provenance, based on a game-theoretic approach to query evaluation. First, we study games G in their own right, and ask how to explain that a position x in G is won, lost, or drawn. The resulting notion of game provenance is closely related to winning strategies, and excludes from provenance all "bad moves", i.e., those which unnecessarily allow the opponent to improve the outcome of a play. In this way, the value of a position is determined by its game provenance. We then define provenance games by viewing the evaluation of a first-order query as a game between two players who argue whether a tuple is in the query answer. For RA+ queries, we show that game provenance is equivalent to the most general semiring of provenance polynomials N[X]. Variants of our game yield other known semirings. However, unlike semiring provenance, game provenance also provides a "built-in" way to handle negation and thus to answer why-not questions: In (provenance) games, the reason why x is not won, is the same as why x is lost or drawn (the latter is possible for games with draws). Since first-order provenance games are draw-free, they yield a new provenance model that combines how- and why-not provenance

Het Nieuwe Telen voor groente-opkweek

Het Nieuwe Telen (HNT) is als systeem ontwikkeld voor de primaire productie bedrijven. Voor de opkweekbedrijven, die in korte teelten het basis uitgangsmateriaal maken is dit systeem niet één op één toepasbaar. Om de in Kas als Energiebron opgedane kennis te laten landen bij plantenkwekerijen moet een analyse en een vertaalslag gemaakt worden. In het project ‘Het Nieuwe Telen voor groente-opkweek’ is door middel van gesprekken met 10 opkweekbedrijven, een workshop en literatuurstudie in kaart gebracht waar de kansen en knelpunten liggen

An Outline of the Bayesian Decision Theory

In this paper we give an outline on the Bayesian Decision Theory.Comment: arXiv admin note: text overlap with arXiv:1409.826