Automatic Computation of a Linear Interval Enclosure

Recently, an alternative interval approximation F(X) for enclosing a factorable function f(x) in a given box X has been suggested. The enclosure is in the form of an affine interval function F(X)= a _i X _i +B where only the additive term B is an interval, the coefficients a _i being real numbers. The approximation is applicable to continuously differentiable, continuous and even discontinuous functions.In this paper, a new algorithm for determining the coefficients a _i and the interval B of F(X) is proposed. It is based on the introduction of a specific generalized representation of intervals which permits the computation of the enclosure considered to be fully automated.     

Gold, an alternative to platinum group metals in automobile catalytic converters

Catalytic convertors based on the use of platinum, palladium and rhodium play a major role in the cleaning of automobile emissions. Gold, when dispersed as nano-sized particles, has demonstrated significant activity in the conversion of toxic components, including carbon monoxide, unburnt hydrocarbons and nitrogen oxides, in engine emissions and some advantages over the platinum group metals. Some research outcomes on the application of nano-sized gold for the conversion of these components are reviewed. Several key issues in relation to its performance and applicability in catalytic convertors such as low-temperature activity and thermal stability and the possibilities of substituting platinum group metals for automobile emission control with gold are discussed.     

New insight into the redox behavior of polyaniline

Polyaniline is one the most promising conducting polymers due to its ability to respond to environmental modifications by change in the properties. Here, we report an unprecedented redox behavior of polyaniline. Namely, propagation of reduction in thin highly organized polyaniline films immersed in acid aqueous medium (see Video 1). The films represent a homogeneous interpenetrating network of nano-sized polyaniline fibrils and water molecules. It is found that the presence of highly hydrated anions like HCOO^? favors both short- and long-range ordering, as well as the propagation of reduction in the polymer.     

Initial loss of cyanide, thiocyanate, and thiosulfate adjuvants following amendment to an oxidic gold ore

Gold extraction and gold phytomining involve the use of adjuvants such as cyanide, thiocyanate, or thiosulfate to facilitate the dissolution of gold and its subsequent recovery. The adjuvants can be applied at high rates, in excess of 1 kg t⁻¹ for some ores. At these concentrations, concerns have been expressed about adjuvant persistence and associated detrimental repercussions for the environment. The incubation study here examined the initial disappearance of these adjuvants in the dark following their amendment at 1 g kg⁻¹ gold ore. Over a 24 d period, nearly 75% of the initial thiocyanate was lost within 24 d while >50% of thiosulfate and cyanide was lost over the same time frame. Cyanide and thiosulfate loss showed an exponential loss while thiocyanate was observed to follow a biphasic relationship. For the oxidic ore used, the adjuvants were not inherently persistent, suggesting that natural attenuation may rapidly promote adjuvant loss under specific conditions.     

On the optimal total processing time using checkpoints

The authors investigate the problem of optimizing the expected blocking time duration by providing a schedule of checkpoints during the required job processing time. They give a general approach for determining the optimal checkpoint schedule and derive some cases when the optimal checkpointing is uniform. The model has applications in unreliable computing systems, multiclient computer service, data transmissions, etc     

Traditional remedies and food supplements. A 5-year toxicological study (1991-1995)

Since 1991, the Medical Toxicology Unit (MTU) at Guys' Hospital, London, has been assessing the toxicological problems associated with the use of traditional and herbal remedies and dietary supplements. This assessment was carried out by evaluating reports to the National Poisons Information Service (London) [NPIS(L)] which provides emergency information to medical professionals. Relevant telephone enquiries to NPIS(L) were identified. Further case details were obtained by follow-up questionnaire, clinical consultation, toxicological analysis of samples from patients and/or products and botanical identification of plant material. Of 1297 symptomatic enquiries evaluated there was a possible/confirmed association in 785 cases. Case series have been identified which substantiate previous reports, including liver problems following the use of Chinese herbal medicine for skin disorders, allergic reactions to royal jelly and propolis and heavy metal poisoning caused by remedies from the Indian subcontinent. Although the overall risk to public health appears to be low, certain groups of traditional remedies have been associated with a number of potentially serious adverse effects. Considering the extent of use of herbal remedies and food supplements a comprehensive surveillance system for monitoring the adverse health effects of these products is essential. Surveillance of a large population is needed for the complex task of identifying the uncommon and unpredictable adverse effects which are potentially serious. In the UK, the Medicines Control Agency responded to the MTU report by recognising the need for vigilance and by incorporating adverse reactions reporting on unlicensed herbal remedies into their drug reaction monitoring function. As a further step to safeguard the patients/consumers an effective single regulatory system is required which would ensure the safety and quality of all herbal remedies and food supplements available in the UK.     

Zur Nitrierung von Ethylenoxid

About the Nitration of Ethylene Oxide Nitration of ethylene oxide with pure nitric acid of different concentrations as well as in presence of sulphuric acid was carried out. The products, ethyleneglycol dinitrate 1 , diethylenglycol dinitrate 2 , triethyleneglycol dinitrate 3 , tetraethylenglycol dinitrate 4 , ethyleneglycol mononitrate 5 , diethyleneglycol mononitrate 6 , and 2, 2′-dinitratediethylsulphate 7 were structurally determined by i. r.- and ¹H-n. m. r.-spectroscopy.