Aluminium nitride coatings on silicon carbide fibres,prepared by pyrolysis of a polymeric precursor

Metallic aluminium was anodically dissolved in an organic electrolyte. A viscous solution, containing a polyiminoalane precursor was obtained. Nicalon (SiC) fibres were thermally pretreated and then coated with this fluid. The coated fibres were dried and calcined at 900 ° C in anhydrous ammonia. Thermal pretreatment of the fibres in nitrogen at 1400 ° C and dip coating with solutions of relatively low aluminium concentrations resulted in dense, nearly uncracked aluminium nitride layers.     

Bainite in steels

The mechanism of the bainite transformation in steels is reviewed, beginning with a summary of the early research and finishing with an assessment of the transformation in the context of the other reactions which occur as austenite is cooled to temperatures where it is no longer the stable phase. The review includes a detailed account of the microstructure, chemistry, and crystallography of bainitic ferrite and of the variety of carbide precipitation reactions associated with the bainite transformation. This is followed by an assessment of the thermodynamic and kinetic characteristics of the reaction and by a consideration of the reverse transformation from bainite to austenite. It is argued that there are useful mechanistic distinctions to be made between the coherent growth of ferrite initially supersaturated with carbon (bainite), coherent growth of Widmanstätten ferrite under paraequilibrium conditions, and incoherent growth of ferrite under local equilibrium or paraequilibrium conditions. The nature of the so-called acicular ferrite is also discussed.     

Sequential Decision Strategies for Machine Interpretation of Speech

Recognition errors made by automatic speech recognition (ASR) systems may not prevent the development of useful dialogue applications if the interpretation strategy has an introspection capability for evaluating the reliability of the results. This paper proposes an interpretation strategy which is particularly effective when applications are developed with a training corpus of moderate size. From the lattice of word hypotheses generated by an ASR system, a short list of conceptual structures is obtained with a set of finite state machines (FSM). Interpretation or a rejection decision is then performed by a tree-based strategy. The nodes of the tree correspond to elaboration-decision units containing a redundant set of classifiers. A decision tree based and two large margin classifiers are trained with a development set to become interpretation knowledge sources. Discriminative training of the classifiers selects linguistic and confidence-based features for contributing to a cooperative assessment of the reliability of an interpretation. Such an assessment leads to the definition of a limited number of reliability states. The probability that a proposed interpretation is correct is provided by its reliability state and transmitted to the dialogue manager. Experimental results are presented for a telephone service application     

Synthesis of N-acryloxysuccinimide copolymers by RAFT polymerization, as reactive building blocks with full control of composition and molecular weights

The reversible addition-fragmentation chain transfer (RAFT) polymerization process was used to synthesize well-defined N-acryloxysuccinimide (NAS) based copolymers, very useful reactive building blocks for various applications. Kinetic studies of RAFT copolymerization of NAS with a bi-substituted acrylamide derivative, N-acryloylmorpholine (NAM), were performed in the presence of tert-butyl dithiobenzoate (tBDB). An excellent control was reached with very high conversions (>95%), molecular weights (MW) up to 80?000 g mol⁻¹ and very narrow molecular weight distributions (MWD) (polydispersity indices, PDI<1.1), as determined by aqueous size exclusion chromatography with on-line light scattering detector (SEC/LS). In addition, the comparison of RAFT and conventional NAM/NAS free radical copolymerization indicated that the apparent reactivity ratios in RAFT are similar to the reactivity ratios determined from conventional copolymerization. An identical azeotropic composition (60/40 NAM/NAS molar ratio) was obtained providing perfectly random poly(NAM-co-NAS) copolymers with full control of composition and MW. These copolymer chains with regularly-distributed reactive functions can be integrated into more complex architectures. As an example, poly[(NAM-co-NAS)-b-NAM] block copolymers with length-varying poly(NAM) block were synthesized with a very efficient control over MW, MWD and composition.     

A new route for the preparation of cyano‐containing poly(N‐isopropylacrylamide) microgel latex for specific immobilization of antibodies

A prepolymerization process was used to prepare functionalized poly(N‐isopropylacrylamide) latexes with surface cyano groups. The functionalized latexes prepared were characterized by FTIR, ¹H NMR, scanning electron microscopy and quasi‐elastic light scattering. In addition, the polymerization conversion and the water‐soluble polymer amounts were quantified. The polymerization conversions were found to be above 80% with 5–14 wt% of water soluble polymer formation. The immobilization of antibody (immunoglobulin) onto such cyano‐containing thermally sensitive particles, suggests the feasibility of specific dipole–dipole interactions between the cyano and hydroxyl functional groups from particle and antibody, respectively. Copyright © 2004 Society of Chemical Industry     

Optimising the baking and frying process using oil‐improving agents

Despite slimness mania and acrylamide scare, the market of fried products is still growing. Frying is an extremely effective way to cook food. A fried product tastes good, has a good flavour and is prepared within a few minutes. Every effort has been made to optimise the frying process. With regard to the quality of the fried food, the quality of the frying oil is very important. In the past, important characteristics of industrial frying oils were oxidative stability, high smoke point and low foaming. Nowadays, new frying fats with various additives, with a healthier fatty acid profile and higher heat stability are emerging. Emulsifiers, anti‐polymerising agents, and natural and synthetic antioxidants improve the performance during frying. Sesamol, rosemary and other natural extracts display strong stabilising effects during the frying operations. Filtration and the use of heat‐stabilising additives help to retard fat degradation and give the producer a larger time‐window for optimum frying. The effectiveness of the treatment with filter aids or mineral adsorbents and the stabilising effects of synthetic and natural agents were compared by using the Rancimat test for testing oxidative stability and the OSET (oxidative stability at elevated temperature) test to determine the stability at the frying temperature.     

Isomeric diacylglycerols – Determination of 1,2‐ and 1,3‐diacylglycerols in virgin olive oil

The “Joint Committee for the Analysis of Fats, Oils, Fatty Products, Related Products and Raw Materials (GA Fett)” has developed the following method for the determination of isomeric diacylglycerols in virgin olive oils to detect the freshness of oils. It is intended to include this method in Section C, Chapter VI of the German Standard Methods.*