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At least 19 recordsLinked to original sources
PubMed2006

A method of test for residual isophorone diisocyanate trimer in new polyester-polyurethane coatings on light metal packaging using liquid chromatography with tandem mass spectrometric detection.

A method of test for residual isophorone diisocyanate (IPDI) trimer in experimental formulation polyester-polyurethane (PEPU) thermoset coatings on metal food packaging is described. The method involves extraction of coated panels using acetonitrile containing dibutylamine for concurrent derivatisation, and then high performance liquid chromatography with electrospray ionisation tandem mass spectrometric detection (LC-MS/MS). Single laboratory validation was carried out using three different experimental PEPU-based coatings. The calibrations were linear, the analytical recovery was good, no interferences were seen, and substance identification criteria were met. The detection limit of the method is around 0.02 micro g/100 cm(2) of coating, which for a typical sized can and assuming complete migration of any residual IPDI trimer, corresponds to about 0.2 micro g/kg food or beverage. Separate studies indicated that, even if migration occurred at such low levels, the IPDI trimer would not be expected to persist in canned aqueous or fatty foodstuffs as it would hydrolyse to the corresponding aliphatic amine or react with food components to destroy the isocyanate moiety. The method of test developed here for residual IPDI trimer in thermoset polyester-polyurethane coatings should prove to be a valuable tool for investigating the cure kinetics of these novel coatings and help to guide the development of enhanced formulations.

Butylamines↗
PubMed2005

[Photoreduction of Se (VI) by marine algae-transitional metals-light system].

Seven marine phytoplankton, including five green algae (Tetraselmis levis, Chlorella autotrophica, Dunaliella salina, Nannochloropsis sp. and Tetraselmis subcordiformis), one diatom (Phaeodactylum tricornutum), one red alga (Porphyridium purpureum), and three usual transitional metals (Fe(III), Cu(II), Mn(II)) were used to make up marine phytoplankton-light or transitional metals-light or marine phytoplankton-transitional metals-light system. In such system, Se(VI) could be transformed into Se(IV) by photoreduction. The species transformation of selenium could be photo-induced by redox reaction of transitional metals. The photochemical activity of marine phytoplankton was confirmed for the first time, because marine phytoplankton could adsorb and concentrated of selenium, transitional metals and organic substances (including the exudation of algae, as reducing agent) which redox potentials were changed. The ratios of Se(VI) to Se(IV) were dominated by the species, the concentration of marine phytoplankton and transitional metals, and it could be enhanced through increasing the concentration of marine algae or the combined effect from marine algae and transitional metals. After photoreduction by ternary system, the ratio of Se(VI) to Se(IV) ranges from 1.17 to 2.85, which is close to the actual value in euphotic layer of seawater. The photochemical process that is induced by marine algae and transitional metals dominative the leading effects on the distribution of oxidation states of selenium.

Chlorophyta↗
PubMed1983

Methods of hazard analysis applied in the light metal industry.

There is a present a wide variety of methods to be used for the identification and evaluation of hazards. The information resulting from a hazard analysis can be used to develop measures for either the elimination or the control of hazards. Hazard analysis has not yet been used very widely in industry. More information is needed, eg, about the applicability of methods to different types of systems. A joint project, where hazard analysis was applied to various fields, was carried out in the Nordic countries. One part of this project concentrated on the light metal industry. A trial was carried out on a production line for which man-machine tasks play an important role. Job analysis was selected as the means of revealing possible accidents. On the production line this procedure turned out to be a good point for systematic investigation. The selection of the methods to be applied within a system should be done carefully. It is important that sufficient knowledge is available both about the characteristics of the system and about the existing methods. The rapid increase of information in this area makes it possible to put hazard analysis to better use in industry.

Accident Prevention↗
PubMed2006

Photo-oxidation of Sb(III) in the seawater by marine phytoplankton-transition metals-light system.

The photo-oxidation of Sb(III) to Sb(V) by marine microalgae (diatom, green and red algae) with or without the presence of transition metals (Fe(III), Cu(II) and Mn(II)). The influence of marine phytoplankton on the photochemistry of antimony was confirmed for the first time. The conversion ratio of Sb(III) to Sb(V) increased with increasing algae concentration and irradiation time. Different species of marine phytoplankton were found to have different photo-oxidizing abilities. The photochemical redox of transition metals could induce the species transformation of antimony. After photo-induced oxidation by marine phytoplankton and transition metals, the ratio of Sb(V) to Sb(III) was in the range of 1.07-5.48 for six algae (Tetraselmis levis, Chlorella autotrophica, Nannochloropsis sp., Tetraselmis subcordiformis, Phaeodactylum tricornutum, and Porphyridium purpureum), and only 0.92 for Dunaliella salina. The distribution of antimony in the sunlit surface seawater was greatly affected by combined effects of marine phytoplankton (main contributor) and transition metals; both synergistic and antagonistic effects were observed. The results provided further insights into the distribution of Sb(III) and Sb(V) and the biogeochemical cycle of antimony, and have significant implications for the risk assessment of antimony in the sunlit surface seawater.

Animals↗
PubMed2004

Light metal hydrides and complex hydrides for hydrogen storage.

The availability of feasible methods for hydrogen storage is one of the key-maybe the key-requirements for the large scale application of PEM fuel cells in cars. There are in principle four different approaches, i.e. cryostorage in liquid form, high pressure storage, storage in the form of a chemical compound which is converted to hydrogen by on-board reforming, or reversible chemical storage in different kinds of storage materials. New developments in the field of chemical storage make such systems attractive compared to the other options. This review will discuss the different possibilities for chemical storage of hydrogen and the focus on the presently most advanced system with respect to storage capacity and kinetics, i.e. catalyzed alanates, especially NaAlH(4).

Journal Article↗
PubMed2005

A new laboratory polymerizing apparatus equipped with halogen and metal halide light sources.

We developed a new laboratory polymerizing unit (Twinkle MIII: M3) equipped with different light sources (a metal halide and two halogen lamps) that could illuminate independently. This study introduced the structure of the curing unit and examined the curing depth of a representative indirect composite (Artglass). The composite material was cured with the following modes: 1) M3 - halogen only; 2) M3 - metal halide only; 3) M3 - both halogen and metal halide (HM); 4) conventional xenon; and 5) preliminary halogen. The results obtained from analysis of variances and post-hoc tests revealed that curing depth was affected significantly (p < 0.05) by both exposure mode and time, and that HM mode exhibited the most favorable curing performance (p < 0.05) among the curing units and polymerization modes. In conclusion, the M3 unit was found to be well suited to polymerizing the composite material tested.

Analysis of Variance↗
PubMed2001

Application of ion beam techniques for preparation of metal ion-implanted TiO2 thin film photocatalyst available under visible light irradiation: metal ion-implantation and ionized cluster beam method.

Transparent TiO2 thin film photocatalysts have been prepared on silica glass plate by an Ionized Cluster Beam (ICB) method. In order to improve the electronic properties of these photocatalysts, transition metal ions (V+, Cr+, Mn+, Fe+) were implanted into the TiO2 thin films at high energy acceleration using an advanced metal ion-implantation technique. The combination of these ion beam techniques can allow us to prepare the TiO2 thin film photocatalysts which can work effectively under visible light (lambda>450 nm) and/or solar light irradiation. The investigation using XAFS and ab initio molecular calculation suggests that the substitution of octahedrally coordinated Ti ions in TiO2 lattice with implanted metal ions is important to modify TiO2 to be able to adsorb visible light and operate under visible light irradiation.

Journal Article↗
PubMed2006

Controlling the passage of light through metal microchannels by nanocoatings of phospholipids.

The flow of polarized light through a metal film with an array of microchannels is controlled by the phase of an optically active, phospholipid nanocoating, even though the coating does not cover the open area of the microchannels. The molecular details of the assembly (DPPC phospholipid monolayer/bilayer on a hexadecanethiol monolayer on a copper- or nickel-coated microarray) were determined using the infrared, surface-plasmon-mediated, extraordinary transmission of the metal microarrays. Infrared absorption spectra with greatly enhanced absorptions by comparison to literature were recorded and used as a diagnostic for the phase, composition, and molecular geometry of these nanocoatings. This approach presents new tools for nanoscale construction in constricted microspaces, which may ultimately be useful with individual microchannels.

Copper↗