Oxide scale formation of modified FeCrAl coatings exposed to liquid lead

Modified FeCrAl coatings were studied with respect to their capability to form a thin protective oxide scale in liquid lead environment. They were manufactured by low pressure plasma spraying and GESA surface melting, thereby tuning the Al content. The specimens were exposed for 900 h to liquid lead containing 10^?6 and 10^?8 wt.% oxygen, respectively, at various temperatures from 400 to 550 °C. Threshold values for an Al content that guarantees the formation of thin protective Al-rich oxide scales are determined, dependent on the respective chromium content, on the presence of yttrium in the modified coating, and on the exposure conditions.     

Design of New Cardanol Derivative: Synthesis and Application as Potential Biobased Plasticizer for Poly(lactide)

A novel biobased plasticizer made of cardanol is designed for poly(lactide) (PLA). This cardanol‐derived plasticizer, i.e., methoxylated hydroxyethyl cardanol (MeCard), is synthesized through methoxylation of the double bonds on the side chain of cardanol, and characterized by ¹H NMR and mass spectrometry. The plasticization effect of MeCard on the molecular structure, morphology, thermal and mechanical properties of PLA is evaluated and compared to that of a commercial cardanol, i.e., hydroxyethyl cardanol (pCard). The plasticization efficiency of MeCard is demonstrated by a substantial decrease of the glass transition temperature and storage modulus together with a significant increase of the elongation at break as compared to neat PLA. Moreover, MeCard exhibits higher plasticization performance than pCard toward PLA. Such behavior is related to a higher miscibility and compatibility between PLA and MeCard thanks to the methoxylation of the double bonds on the side chain of cardanol as shown by SEM micrographs.

     

Tunable diode laser absorption spectroscopy in coiled hollow optical waveguides

We demonstrate tunable diode laser absorption spectroscopy of CO2 and NH3 near 1.5 microm using a distributed feedback diode laser in conjunction with hollow optical waveguides as long-path sample cells. The waveguides are coiled to reduce the physical extent of the system. The small volume of the waveguide provides rapid instrument response to changes in gas concentration. To reduce the pressure drop associated with long lengths and high flow rates, we perforate the waveguides in a novel geometry providing parallel pneumatic paths while maintaining optical path length. A minimum detectable absorbance of 3.5 x 10(-5) in a 3-m section of waveguide is demonstrated.     

Disinformation: The Use of False Information

The distinction between misinformation and disinformation becomes especially important in political, editorial, and advertising contexts, where sources may make deliberate efforts to mislead, deceive, or confuse an audience in order to promote their personal, religious, or ideological objectives. The difference consists in having an agenda. It thus bears comparison with lying, because lies are assertions that are false, that are known to be false, and that are asserted with the intention to mislead, deceive, or confuse. One context in which disinformation abounds is the study of the death of JFK, which I know from more than a decade of personal research experience. Here I reflect on that experience and advance a preliminary theory of disinformation that is intended to stimulate thinking on this increasingly important subject. Five kinds of disinformation are distinguished and exemplified by real life cases I have encountered. It follows that the story you are about to read is true.     

The Separation and Identification of Higher Molecular Weight Fullerenes

A nonaqueous, reversed-phase separation of the fullerenes is described. The bonded-phase, a polymeric octadecyl one, has previously been shown to have a very large separating power for nonplanar polycyclic aromatic hydrocarbons. This work shows that this shape selectivity also is found with the fullerenes, allowing very short retention times while maintaining separation of the C₆₀ and C₇₀ species. Additionally, a fraction containing larger fullerenes was isolated. UV absorbance spectra of these species were obtained. Preliminary spectra of hydrogen chemical ionization mass spectra were also obtained and showed that the fullerenes adsorb large amounts of molecular hydrogen.     

A vector based on the SV40 origin of replication and chromosomal S/MARs replicates episomally in CHO cells

We have developed an episomal replicating expression vector in which the SV40 gene coding for the large T-antigen was replaced by chromosomal scaffold/matrix attached regions. Southern analysis as well as vector rescue experiments in CHO cells and in Escherichia coli demonstrate that the vector replicates episomally in CHO cells. It occurs in a very low copy number in the cells and is stably maintained over more than 100 generations without selection pressure.     

A fully bypassed six-issue integer datapath and register file on the Itanium-2 microprocessor

The six-issue integer datapath of the second-generation Itanium microprocessor is described. Pulse techniques enable a high-speed, 20-ported, 128-entry, 65 bit register file with only 12 wordlines per register. A four-stage operand bypass network achieves a fully bypassed design with operands sourced from 34 locations with 16 destinations. To control this network, over 280 bypass comparators are utilized. Using half a clock for execution and half a clock for bypass, each result is available for the next instruction. Functional units are pre-enabled, reducing power consumption by 15% while eliminating a stage of result mixing and improving performance. The part is fabricated in a six-layer 0.18 /spl mu/m process and operates at 1.0 GHz at 1.5 V, consuming less than 130 W in about 420 mm/sup 2/.     

Anwendung der Methode der finiten Elemente und des Vektor-Preisach-Modells zur Berechnung ebener magnetostatischer Felder in hysteresebehafteten Medien

Übersicht Eine Anwendung der Methode der finiten Elemente zur Lösung magnetostatischer Probleme unter Berücksichtigung von Hystercsccrscheinungen wird vorgestellt. Zur Behandlung der Hystereseeffekte wird das Vektor-Preisach-Modell eingesetzt. Die Maxwellschen Gleichungen der Magnetostatik werden diskretisiert und mit Hilfe eines besonderen iterativen Verfahrens gelöst. Dieses Iterationsverfahren ist für lineare, nichtlineare und hysteresebehaftete Probleme geeignet. Die Iterationsvorschrift kann entweder alsM(H)- oder alsM(B)-Iteration formuliert werden. Zur Anwendung des Vektor-Preisach-Modells muß dieM(H)-Iteration in Verbindung mit einer zeitdiskreten Berechnungsmethode benutzt werden.Für das Vektor-Preisach-Modell existieren Identifikationsverfahren, die eine Anpassung des Modells an gemessene Kennlinien erlauben. Daneben läßt sich das Modell leicht innerhalb eines Computerprogrammes implementieren. Diese Eigenschaften waren ausschlaggebend für den Einsatz des Modells. Verschiedene Beispiele wurden berechnet und die numerischen mit den analytischen Lösungen verglichen, wobei sich eine gute Übereinstimmung zeigte.

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Application of the finite element method and the vector-Preisach-model for the calculation of 2-dimensional magnetostatic fields in media with hysteresis

Contents A finite element method for magnetostatic problems taking into account hysteresis is presented. The vector Preisach model is used to deal with hysteresis effects. Maxwell equations describing magnetostatic problems are discretized and solved by applying a special iterative technique. This technique is suitable for linear, nonlinear and hysteresis problems. The iteration process may be formulated either in terms ofM(H) orM(B). For the application of the vector Preisach modelM(H) iteration must be used in connection with a time stepping scheme.The motive for using the vector Preisach model is the existence of methods for fitting experimental data by the model as well as its advantage of straightforward implementation in a computer code. Several examples have been calculated and compared with analytical solutions showing good accuracy.

     

Philosophical aspects of program verification

A debate over the theoretical capabilities of formal methods in computer science has raged for more than two years now. The function of this paper is to summarize the key elements of this debate and to respond to important criticisms others have advanced by placing these issues within a broader context of philosophical considerations about the nature of hardware and of software and about the kinds of knowledge that we have the capacity to acquire concerning their performance.