Corrosion rate monitoring by the linear polarization method

The characteristics of the electrochemical system and the criteria for a correct application of the method of polarization resistance aimed at the evaluation of the corrosion current density are carefully discussed. The mathematical theory of the validity of the linear approximation of the kinetic law, over a suitable interval round the mixed potential, is based on the integral representation of the remainder of the series expansion of i(ΔE). This scheme makes it possible to compare the contribution of the linear term with that due to the non-linear remainder by introducing a criterion which permits the goodness of the approximation to be verified. Numerical examples have shown that the interval width, where the system could exhibit an approximate linear behaviour, depends on the three parameters α, β and and is independent of the bending radius of the curve i = i(ΔE) at ΔE = 0. Furthermore, the absolute values of the left and right bounds ΔE₁ and ΔE_T are usually different. They are equal only when α = β. Examination of some experimental data concerning the behaviour of Armco iron in H₂SO₄ I N solutions inhibited with n-decylamine has demonstrated that the choice of the proportionality factor (α + β)⁻¹ plays an important role when measurements are aimed at a quantitative evaluation of the corrosion rate.     

Interferon (IFN) consensus sequence-binding protein, a transcription factor of the IFN regulatory factor family, regulates immune responses in vivo through control of interleukin 12 expression

Mice with a null mutation of the gene encoding interferon consensus sequence-binding protein (ICSBP) develop a chronic myelogenous leukemia-like syndrome and mount impaired responses to certain viral and bacterial infections. To gain a mechanistic understanding of the contributions of ICSBP to humoral and cellular immunity, we characterized the responses of control and ICSBP-/- mice to infection with influenza A (flu) and Leishmania major (L. major). Mice of both genotypes survived infections with flu, but differed markedly in the isotype distribution of antiflu antibodies. In sera of normal mice, immunoglobulin (Ig)G2a antibodies were dominant over IgG1 antibodies, a pattern indicative of a T helper cell type 1 (Th1)-driven response. In sera of ICSBP-/- mice, however, IgG1 antibodies dominated over IgG2a antibodies, a pattern indicative of a Th2-driven response. The dominance of IgG1 and IgE over IgG2a was detected in the sera of uninfected mice as well. A seeming Th2 bias of ICSBP-deficient mice was also uncovered in their inability to control infection with L. major, where resistance is known to be dependent on IL-12 and IFN-gamma as components of a Th1 response. Infected ICSBP-deficient mice developed fulminant, disseminated leishmaniasis as a result of failure to mount a Th1-mediated curative response, although T cells remained capable of secreting IFN-gamma and macrophages of producing nitric oxide. Compromised Th1 differentiation in ICSBP-/- mice could not be attributed to hyporesponsiveness of CD4(+) T cells to interleukin (IL)-12; however, the ability of uninfected and infected ICSBP-deficient mice to produce IL-12 was markedly impaired. This indicates that ICSBP is a deciding factor in Th responses governing humoral and cellular immunity through its role in regulating IL-12 expression.     

Preparation by flame spray pyrolysis of ABO3±δ catalysts for the flameless combustion of methane

Perovskitic mixed oxides prepared through flame-spray pyrolysis possess a good stability in high-temperature application, viz. the catalytic flameless combustion of methane. Some preparation operating parameters are here analysed, such as O₂ pressure drop along the spraying nozzle, O₂ discharge velocity and flow rate. These parameters have been correlated with specific surface area, activity and durability of the prepared samples, as well as with flame temperature, varied by using different fuel mixtures. It was found that specific surface area increases with increasing O₂ velocity and flow rate and with decreasing the combustion enthalpy of the solvent mixture. This reflects on both activity and durability of the catalyst.     

Study of the metal dusting behaviour of high‐temperature alloys

The corrosion phenomenon named metal dusting has been observed in many high‐temperature industrial plants. An experimental research programme is being carried out into the degradation resistance of wrought and cast commercial and development high‐temperature alloys in H₂/CO gas mixtures at temperatures of 550°C to 750°C. Emphasis is placed on very high carbon activities, consistent with the next generation of steam‐reforming and similar plants that are susceptible to metal dusting. The overall programme is concerned with the mechanisms of initiation and propagation of dusting and the sensitivity to damage of the more resistant alloys, as a function of environmental parameters. Initial tests have been carried out on a number of commercial alloys: Alloy 600, 693, 602CA, 601, 603 XL, 671, 617, 690 (wrought), and H46M (cast). The specimens were exposed to a gas mixture of high carbon activity at 650°C for a total of 1000 hours. Many of the alloys showed at least the initial stages of metal dusting. Preliminary analysis using electron microscopy revealed that initiation of metal dusting is influenced by microstructure, stress state and composition. In some cases, attack was enhanced at stress points, such as corners and edges. Sample holders were found to influence strongly the length of the initiation period for the onset of the corrosion phenomenon. The reaction layers in the alloy beneath areas of damage were analysed by EDX and EPMA. Mechanical characterisation of such areas has been carried out using nanoindentation methods. These early results are discussed in terms of the effectiveness of oxide scales in inhibiting the onset of damage and presence of impurities in the ceramic holder in initiating the onset of damage.     

Team Automata for Security: – A Survey –

In [Kleijn, J., Team Automata for CSCW – A Survey –, Petri Net Technology for Communication-Based Systems—Advances in Petri Nets, LNCS 2472, Springer, 2003, 295–320], Kleijn presented a survey of the use of team automata for the specification and analysis of phenomena from the field of computer supported cooperative work, in particular notions related to groupware systems. In this paper we present a survey of the use of team automata for the specification and analysis of some issues from the field of security. In particular, we show how team automata can adequately be used to model and verify various access control policies, multicast/broadcast communication protocols, and general (cryptographic) communication protocols.     

THe cost of radiotherapy. Piedmontese experience]

The blood supply of hepatocellular carcinoma (HCC) is primarily arterial. Recent studies reported differences of vascular, especially arterial, supply among low- and high-grade dysplastic nodules and HCC. We assessed arterialization using monoclonal antibody specific for smooth muscle actin as well as simultaneous changes in sinusoidal capillarization in cirrhotic nodules, dysplastic nodules, and HCC. We immunohistochemically stained 56 cirrhotic nodules, 20 low-grade dysplastic nodules, 27 high-grade dysplastic nodules, and 20 HCCs for alpha smooth muscle actin (to identify unpaired arteries (i.e., arteries not accompanied by bile ducts) and CD34 (indicating sinusoidal capillarization). Distribution and number of unpaired arteries and distribution of sinusoidal capillarization were graded semiquantitatively. Unpaired arteries were rare in cirrhotic nodules, significantly more common in dysplastic nodules of both types (p < 0.00001), and most common in HCC. Sinusoidal capillarization was least common in cirrhotic nodules, significantly more common in dysplastic nodules (p < 0.0035), and most common in HCC. No topographic relationship between unpaired arteries and sinusoidal capillarization was identified. These findings showed that (1) distributions of sinusoidal capillarization and unpaired arteries in dysplastic nodules are intermediate between those in cirrhotic nodules and HCC, supporting dysplastic nodules as premalignant lesions; (2) unpaired arteries are histologically useful for distinguishing dysplastic nodules from large cirrhotic nodules; and (3) areas of sinusoidal capillarization within dysplastic nodules are unrelated to location of arterialization.     

On the representation and management of medical records in a knowledge-based system

The need for adapting Hospital Information Systems (HISs) to new applications (aimed at clinical data management) and to the ever growing population requires an evolution from both the representation and the usability points of view. The goal of this paper is to discuss the interdependencies of the advanced data representation models necessary to the new HISs and the interaction requirements. In particular, we present the technical taken in the MILORD (Multimedia Interaction with Large Object-oriented Radiological and clinical Databases) project to implement a departmental environment which integrates different kinds of clinical data in a user-friendly and homogeneous way. The implementation platform of the MILORD system is based on results obtained in the KIWIS project, which produced an advanced knowledge-base environment for large database systems. The interaction with a HIS is analyzed identifying the HIS-specific interaction tasks, the typical phases of the interaction with an information system, and the necessary interaction paradigms. In particular we describe the approach adopted in KIWIS for overcoming the problem of querying object-oriented databases and we discuss the new requirements that multimediality poses on the interaction paradigms.     

Quantifizierende calciumspezies-analytik im wein zur frage der calciumstabilit?t

Zusammenfassung Die Calciumspezies-Stabilität als dekadischer Logarithmus der Komplex-Stabilitätskonstanten nach dem Massenwirkungsgesetz in Wein wird mit Hilfe der Direktpotentiometrie mit Ca-selektiver Elektrode (für die Calciumionenkonzentration) sowie der Photometrie (Ca-Gesamtgehalt) in 16 lager-stabilen Weinen (Ca-Gehalte zwischen 60 und 120 mg/l) mit 3,50±0,20 (Bereich 3,11–3,79) ermittelt. Durch Methodenvergleiche (Photometrie und AAS für Gesamtgehalte sowie Direktpotentiometrie und Ionenaustauschmethode für die Ionenkonzentration) wurden diese Ergebnisse abgesichert. Die Anwendung von Weinbehandlungsverfahren wie der Adsorption phenolischer Stoffe an Polyvinylpolypyrrolidin (PVPP) sowie der Ultrafiltration zur Abtrennung höhermolekularer Eiweißstoffe zeigte keine wesentlichen Veränderungen der Elementspezies-Stabilitäten. Bei einer Entsäuerung mit CaCO₃ oder nach der Doppelsalz-Entsäuerung wurde dagegen nicht nur ein Anstieg der Calciumgesamtgehalte auf 200 bis 535 mg/1 sondern auch eine deutliche Abnahme der Calciumspezies-Stabilität auf Werte von 2,2 bis 2,8 festgestellt. die nach dem Auskristallisieren von Calciumverbindungen nach einigen Wochen wieder Werte um 3 erreicht. Die Lagerstabilität eines Weines im Hinblick auf Calcium kann somit nach der Bestimmung der Calciumspezies-Stabilität beurteilt werden.

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Quantifying analysis of calcium species in wine from the point of view of calcium stability

Summary The stability of calcium species, expressed as the decadic logarithm of the complex stability constant after the chemical equilibrium had been established, was determined to be 3.50 ± 0.20 (range 3.11–3.79) by direct potentiometry with a calcium-selective electrode (for the calcium ion concentration) as well as photometry (total Ca content) in 16 storage-stable wines (Ca contents between 60 and 120 mg/1). By comparing the methods of photometry, AAS (for the total content) and direct potentiometry as well as ion-exchange method for ion concentrations, the results were verified. The treatment of the wine by the adsorption of phenolic substances on polyvinylpolypyrrolidine (PVPP) and by ultrafiltration for the separation of higher molecular proteins showed no significant changes in the stabilities of the calcium species. After deacidification with CaCO₃ or after salt deacidification had been performed twice, not only an increase in the total calcium content occured (200–535 mg/1), but there was also an evident decrease in the stabilities of the calcium species, which had values of 2.2–2.8 and reached values of 3 after crystallization of the calcium species. The storage stability of a wine, with respect to calcium, can be estimated after the determination of the stability of the calcium species.