Infrared Spectroscopic Studies of the Hydrolysis Reaction During Leaching of Heavy-Metal Fluoride Glasses

In this work, the interfacial reactions of heavy-metal fluoride glasses with water have been investigated by Fourier transform infrared spectroscopy. High dilution and stirring conditions were maintained to prevent any influence of pH drift and reprecipitation. From comparisons of the integrated absorption peak areas for the O-H stretching and H-O-H bending vibrations in the glass with those for molecular water, the contributions of metal hydroxyls formed in the corrosion layer can be separated from the total O-H band. The comparison between the infrared spectra for leached samples and hydroxides of the glass components show the presence of Zr-OH and La-OH groups in ZrF₄-based glasses after leaching and drying and of Th-OH groups in ThF₄ glass, indicating the existence of F.^-/OH^- ion exchange between the glass surface and water.     

FLASH DISCHARGE OF SUPERCRITICAL FLUID AND HIGH PRESSURE GAS THROUGH PIPES: EXPERIMENTAL RESULTS AND MODELLING

Although the flash discharge of a supercritical fluid is of key importance for the safe design of safety valves and effluent lines, very few experimental and theoretical results have been obtained in the literature. In this paper is reported a systematic experimental study concerning the flash discharge of supercritical and gaseous Co₂, and gaseous N₂ under different conditions: temperature, pressure and mass of fluid, diameter and length of discharge pipes. The discharge flux can reach as high as 30000 kg. m^?2 ·s^?1 A theoretical model is developed for predicting the variation of fluid mass and other parameters during a discharge, and found to agree with observations to a first approximation.     

High pressure and pasteurization effect on duck foie gras

The effects of combined high pressure (300 and 400 MPa) and low temperature (50°C) treatments on the microbial contamination of duck foie gras samples were compared with those of classical thermal pasteurization (85°C at the coldest point). A multilayer packaging film (PE/PA/PE) was selected from two films commonly used for these types of food, by preliminary tests showing its ability to limit microbiological development in such samples. In each experiment, microbiological contamination was analysed on treated and untreated samples, and results were systematically compared with those obtained from a classically pasteurized sample of the same liver. A pasteurization type effect (drastic reduction of vegetative mesophilic and psychrophilic contaminations, destruction of coliforms and of Staphylococcus aureus ) was obtained at this temperature with samples pressurized at 400 MPa for at least 10 min.     

Extraction and Charcterization of Pectins from Sugar Beet Pulp

Conditions (pH, temperature, time) for the extraction of sugar beet pulp pectins were studied on a laboratory scale and transposed into a pilot plant. Good yields (～ 14%) of pectins are obtained if the pulp is treated at pH 1.0, 85°C for 1 hr. The characteristics of the pilot extracted pectins are very close to those of the laboratory ones, except for a lower molecular weight (～30,000 daltons). Their physicochemical properties confirm their poor gelling ability.     

Subspace model identification Part 1. The output-error state-space model identification class of algorithms

In this paper, we present two novel algorithms to realize a finite dimensional, linear time-invariant state-space model from input-output data. The algorithms have a number of common features. They are classified as one of the subspace model identification schemes, in that a major part of the identification problem consists of calculating specially structured subspaces of spaces defined by the input-output data. This structure is then exploited in the calculation of a realization. Another common feature is their algorithmic organization: an RQ factorization followed by a singular value decomposition and the solution of an overdetermined set (or sets) of equations. The schemes assume that the underlying system has an output-error structure and that a measurable input sequence is available. The latter characteristic indicates that both schemes are versions of the MIMO Output-Error State Space model identification (MOESP) approach. The first algorithm is denoted in particular as the (elementary MOESP scheme). The subspace approximation step requires, in addition to input-output data, knowledge of a restricted set of Markov parameters. The second algorithm, referred to as the (ordinary MOESP scheme), solely relies on input-output data. A compact implementation is presented of both schemes. Although we restrict our presentation here to error-free input-output data, a framework is set up in an identification context. The identification aspects of the presented realization schemes are treated in the forthcoming Parts 2 and 3.     

Electron cryo-microscopy of vitrified bulk biological specimens: ideal and real structures of water—lipid phases

Lipid-water mixtures were studied by X-ray cryodiffraction in order to assess the structural changes during freezing. We show that the water of aqueous lipid phases, in the concentration range of 10–30% (water weight/total weight), is vitrified by high-pressure freezing. Vitrified lipid phases can be cryo-sectioned and imaged by electron cryomicroscopy. Both the ideal or average and the real or local structures of the lipid mixtures can be studied at a resolution better than 2 nm. While the average structure of the lipid phases is in good agreement with that determined by X-ray diffraction, the local structure reveals features that might play an important role in the function of biological membranes such as in endo- and exocytosis.     

Interfaces in Oriented Al2O3-ZrO2 (Y2O3) Eutectics

Oriented samples of Al₂O₃-ZrO₂ (Y₂O₃) eutectics consisting of an alumina matrix with zirconia dispersoids were grown by directional solidification. Preferred growth directions and epitaxial relations were determined from X-ray and electron diffraction analyses. Imaging of interfaces was performed by high-resolution transmission electron microscopy on oriented platelets. Semicoherent interfaces were observed with faceting along crystallographic planes of both phases.     

Review : Reticulocyte maturation: mitoptosis and exosome release

During the differentiation of erythroid cells, a vast program of maturation takes place, leading to decay or elimination of organelles, including the nucleus, mitochondria, ribosomes, lysosomes, endoplasmic reticulum and Golgi apparatus. During the last step of red cell maturation, remaining organelles, primarily mitochondria and ribosomes but also vestiges of others are finally cleared from the cell. This cleaning session also affects specific proteins that are partially or entirely removed from the cell surface. The interplay of the various events and their causal relationships are approached here.     

ARMA models,their Kronecker indices and their McMillan degree

This paper highlights some difficulties with the use of ARMA models with leading unit coefficient matrix in system identification. It is shown that the McMillan degree of such models is not in any easy way related to the row degrees of the polynomial factors of the ARMA model. A rank test is given for the McMillan degree of such models and it is shown that this degree will generically be a multiple of the dimension of the observation vector.