An in situ time-dependent study of the photodimerisation of chloro-derivatives of trans-cinnamic acid using infrared microspectroscopy with a synchrotron radiation source

The photodimerisation of single crystals of substituted cinnamic acid has been monitored continuously by infrared microscopy using a synchrotron source. The beta-form of 2,4-dichloro-trans-cinnamic acid dimerises under ultraviolet irradiation to form the corresponding beta-truxinic acid derivative in a reaction which follows strictly first order kinetics. By contrast the corresponding reactions in single crystals of beta-2-chloro-trans-cinnamic acid and beta-4-chloro-trans-cinnamic acid deviate somewhat from first order kinetics as a result of solid-state effects. In all three cases the reactions proceed smoothly from monomer to dimer with no hint of any reaction intermediate.

Use of HNO3 as the source of NO to prepare a nitric oxide complex of ruthenium

Reaction of cis-Ru(bisox)(2)Cl-2, where bisox is 4,4,4',4'-tetramethyl-2,2'-bisoxazoline, with HNO3 in 1 : 4 molar proportion in boiling water under N-2 atmosphere and subsequent addition of an excess of NaClO4 center dot H2O yields [Ru(bisox)(HL)(NO)](ClO4)(NO3) (1). HL is a hydrolysed form of bisox where one of the oxazoline rings opens up. X-Ray crystallography shows that 1 contains an octahedral RuN5O core. HL binds the metal through an imino N, an amide N and an alcoholic O atom. Reaction of cis-Ru(bisox)(2)Cl-2 with an excess of NaNO2 in water gives cis-Ru(bisox)(2)(NO2)(2) (2). On acidification by HClO4 in methanol, 2 is smoothly converted to cis-[Ru(bisox)(2)(NO2)(NO)](ClO4)(2) (3) due to equilibrium (1).

Nitrogen management is essential to prevent tropical oil palm plantations from causing ground-level ozone pollution

More than half the world's rainforest has been lost to agriculture since the Industrial Revolution. Among the most widespread tropical crops is oil palm (Elaeis guineensis): global production now exceeds 35 million tonnes per year. In Malaysia, for example, 13% of land area is now oil palm plantation, compared with 1% in 1974. There are enormous pressures to increase palm oil production for food, domestic products, and, especially, biofuels. Greater use of palm oil for biofuel production is predicated on the assumption that palm oil is an "environmentally friendly'' fuel feedstock. Here we show, using measurements and models, that oil palm plantations in Malaysia directly emit more oxides of nitrogen and volatile organic compounds than rainforest. These compounds lead to the production of ground-level ozone (O-3), an air pollutant that damages human health, plants, and materials, reduces crop productivity, and has effects on the Earth's climate. Our measurements show that, at present, O-3 concentrations do not differ significantly over rainforest and adjacent oil palm plantation landscapes. However, our model calculations predict that if concentrations of oxides of nitrogen in Borneo are allowed to reach those currently seen over rural North America and Europe, ground-level O-3 concentrations will reach 100 parts per billion (10(9)) volume (ppbv) and exceed levels known to be harmful to human health. Our study provides an early warning of the urgent need to develop policies that manage nitrogen emissions if the detrimental effects of palm oil production on air quality and climate are to be avoided.

Synthesis of bischromones by deformylative Mannich type reaction on chromone-3-carbaldehyde using alpha-aminoacid as the source of amine

Chromone-3-carbaldehyde reacts with N-methylglycine or glycine in the presence of excess formaldehyde to produce N-(chromone-3-ylmethyl)-N-methylglycine or N,N-di(chromone-3-ylmethyl)glycine, respectively, by a deformylative Mannich type reaction. Use of alanine or leucine or methionine in place of glycine produces N-(chromone-3-ylmethyl)alanine/-leucine/-methionine, respectively. (C) 2009 Elsevier Ltd. All rights reserved.

A study of the effect of heat source location in a ventilated room using multiple regression analysis

Multiple regression analysis is a statistical technique which allows to predict a dependent variable from m ore than one independent variable and also to determine influential independent variables. Using experimental data, in this study the multiple regression analysis is applied to predict the room mean velocity and determine the most influencing parameters on the velocity. More than 120 experiments for four different heat source locations were carried out in a test chamber with a high level wall mounted air supply terminal at air change rates 3-6 ach. The influence of the environmental parameters such as supply air momentum, room heat load, Archimedes number and local temperature ratio, were examined by two methods: a simple regression analysis incorporated into scatter matrix plots and multiple stepwise regression analysis. It is concluded that, when a heat source is located along the jet centre line, the supply momentum mainly influences the room mean velocity regardless of the plume strength. However, when the heat source is located outside the jet region, the local temperature ratio (the inverse of the local heat removal effectiveness) is a major influencing parameter.

Effect of damper and heat source on wind catcher natural ventilation performance

Experimental wind tunnel and smoke visualisation testing and CFD modelling were conducted to investigate the effect of air flow control mechanism and heat source inside rooms on wind catchers/towers performance. For this purpose, a full-scale wind catcher was connected to a test room and positioned centrally in an open boundary wind tunnel. Pressure coefficients (C-p's) around the wind catcher and air flow into the test room were established. The performance of the wind catcher depends greatly on the wind speed and direction. The incorporation of dampers and egg crate grille at ceiling level reduces and regulates the air flow rate with an average pressure loss coefficient of 0.01. The operation of the wind catcher in the presence of heat sources will potentially lower the internal temperatures in line with the external temperatures.

Corynebacterium atypicum sp. nov., from a human clinical source, does not contain corynomycolic acids

An unusual Gram-positive, facultatively anaerobic, catalase-positive, diphtheroid-shaped organism originating from an unknown human clinical source was characterized by biochemical, molecular chemical and molecular phylogenetic methods. Based on its morphological and biochemical characteristics and the presence of a murein based on meso-diaminopimelic acid, the unidentified organism was tentatively assigned to the genus Corynebacterium. However, the unknown organism was found to lack the distinctive, short-chain corynomycolic acids that are considered to be characteristic of this genus. Despite the absence of these characteristic lipids, comparative 16S rRNA gene sequencing showed that the unknown bacterium was phylogenetically a member of the genus Corynebacterium and was distinct from all currently known species. Based on both phenotypic and 16S rRNA sequence considerations, it is proposed that the unknown organism be classified as a novel species, Corynebacterium atypicum sp. nov. The type strain of C. atypicum is strain R2070(T) (= CCUG 45804(T) = CIP 107431(T)).

Different splitting techniques with application to air pollution models

Splitting techniques are commonly used when large-scale models, which appear in different fields of science and engineering, are treated numerically. Four types of splitting procedures are defined and discussed. The problem of the choice of a splitting procedure is investigated. Several numerical tests, by which the influence of the splitting errors on the accuracy of the results is studied, are given. It is shown that the splitting errors decrease linearly when (1) the splitting procedure is of first order and (2) the splitting errors are dominant. Three examples for splitting procedures used in all large-scale air pollution models are presented. Numerical results obtained by a particular air pollution model, Unified Danish Eulerian Model (UNI-DEM), are given and analysed.

Impact of future climate changes on high pollution levels

Changes in climate variability as well as changes in extreme weather and climate events in the 20th century, especially those that took place during the last two to three decades of the 20th century, have been discussed in many recent scientific publications. Attempts to project the results of such studies in the future have been made under different assumptions. In this paper, we have chosen one of the well-known scenarios predicting changes of the climate in the world during the last 30 years of the 21st century. This scenario is used, together with several general predictions related to the future climate, to produce three climatic scenarios. The derived climatic scenarios are used to calculate predictions for future pollution levels in Denmark and in Europe by applying the Unified Danish Eulerian Model (UNI-DEM), on a space domain containing the whole of Europe.