53 layer composition

Die cut metal lamiaates are also appHed to plastics for decorative effects, or for radio frequeacy iaterfereace shielding. These lamiaates are formed by vacuum depositioa, or by attachmeat of foil to a plastic layer for easier handling. Multiple layer composites of plastic and aluminum are used for specialized packagiag, especially for moisture or gas barriers. 

The use of RBS concurrendy with ERS is necessary for the complete derivation of a hydrogen profile, and it offers some simplifications of analysis. For example, for thin-layer spectra that have been normalized for a common ion fluence Qand solid angle SI, the total yields Y (the areas under the spectral peaks) may be compared in order to derive the layer composition. For... 

J. M. Whitney and J. E. Ashton, Effect of Environment on the Elastic Response of Layered Composite Piates, AIAA Journal, September 1971, pp. 1708-1713. 

The filaments of all plant fibers consist of several cells. These cells form crystalline microfibrils (cellulose), which are connected together into a complete layer by amorphous lignin and hemi-cellulose. Multiple layers stick together to form multiple layer composites, filaments. A single cell is subdivided into several concentric layers, one primary and three secondary layers. Figure 5 shows a jute cell. The cell walls differ in their composition and in the orientation of the cellulose microfibrils whereby the characteristic values change from one natural fiber to another. 

C, E curves have been obtained for Zn(0001) andZn(lOTO) at various crci with different additions of tu.630,634-636 The data for Zn(0001) at Cju = const have been used to obtain C"1, Ql plots. Nonlinear plots have resulted, with the value of the reciprocal slope remarkably dependent on ctu- At c-ru = 0 1 M, the reciprocal slope of the PZ plot is 1.1, increasing with decreasing c-ru Such an effect has been related to the weak specific adsorption of OH" on Zn. This explanation has been critically discussed by Vorotyntsev,74 who has assumed that the effect635,636 is connected with the variation in the compact layer composition of the Z11/H2O + TU interface as cjv varies. 

The recycling of contaminated polyurethane waste is described with reference to a glycolysis process developed by Bayer and Daimler-Benz in which the wastes from three-layer composite instrument panels are treated. The reuse of contaminated PU is achieved by dispersely integrating the impurities in the secondary polyol during the glycolytic dissociation. The impurities are modified in such a way that they act as a filler in the secondary polyol. 3 refs. 

This paper describes application of mathematical modeling to three specific problems warpage of layered composite panels, stress relaxation during a post-forming cooling, and buckling of a plastic column. Information provided here is focused on identification of basic physical mechanisms and their incorporation into the models. Mathematical details and systematic analysis of these models can be found in references to the paper. 

Warpage of layered composite panels during cooling. 

Temperature changes in layered composites lead to shape distortion via spatial differences in material properties. Our original interest in the phenomenon was motivated by quality control during the manufacturing of the boxes for refrigerators and freezers. These boxes are made from a steel sheet as an outside layer, a plastic liner and urethane foam in the middle. In our case, the liner was made from... 

By the n-layer composite scheme of period m (of order m) we generally mean a system of differential equatioins with operator coefficients... 

Several particular cases will be given special investigation. For m = 1 the composite scheme (41) falls within the category of standard n-layer schemes. For n = 2 the describing scheme is termed a two-layer composite scheme of period m... 

Aqueous solutions of the salts KCl and NH4NO3 are of interest inasmuch as here the mobilities (and also the diffusion coefficients) of the anion and cation are very similar. The higher the concentration of these salts, the larger is the contribution of their ions to transition-layer composition and, as can be seen from Table 5.1, the lower the diffusion potentials will be at interfaces with other solutions. This situation is often used for a drastic reduction of diffusion potentials in cells with transference. To this end one interposes between the two solutions a third solution, usually saturated KCl solution (which is about 4.2mol/L) ... 

The layer of titanium and ruthenium oxides usually is applied to a titanium substrate pyrolytically, by thermal decomposition (at a temperature of about 450°C) of an aqueous or alcoholic solution of the chlorides or of complex compounds of titanium and rathenium. The optimum layer composition corresponds to 25 to 30 atom % of ruthenium. The layer contains some quantity of chlorine its composition can be written as Ruq 2sTio 750(2- c)Cl r At this deposition temperature and Ru-Ti ratio, the layer is a poorly ordered solid solution of the dioxides of ruthenium and titanium. Chlorine is completely eliminated from the layer when this is formed at higher temperatures (up to 800°C), and the solid solution decomposes into two independent phases of titanium dioxide and ruthenium dioxide no longer exhibiting the unique catalytic properties. 

Optimization of the catalyst layer composition and thickness in PEFCs for maximum catalyst utilization in operation on air and on impure hydrogen feed streams [Wilson, 1993 Springer et al., 1993]. 

The most recent improvements in Pt catalyst utilization U by optimization of catalyst layer composition and stmcture have led to catalyst utilizations as high as 80%, or more, determined as the ratio between measured ORR current per geometric square centimeter of electrode area and the current expected from the total measured Pt surface area per geometric square centimeter of the electrode, i.e.,... 

For the a-Pt02 system, we find that above an electrode potential of 1.2 V, the (001) surface with bulk composition is most stable and shows only minor relaxation effects (denoted as (OOl)-O in Fig. 5.11a). This surface structure corresponds to experimental UHV measurements of surface oxides on Pt(llO), supported by DFT calculations [Li et al., 2004]. In the case of a very thin surface layer, the layer composition might even be PtO. Increasing the electrode potential above 2.0 V would cause stronger interactions with the surrounding water dipoles and lead to a o -PtO2(011) surface with an enrichment of oxygen (as 0 ) on the surface. 

Figure 5.32. Illustrating common configurations of elements that may be quantified by AES analysis (a) homogeneous (b) large, well-defined structures varying laterally and with depth (c) small, well-defined structures varying laterally and with depth, (d) monolayer segregants and absorbed layers (e) layered composition gradients and (f) a catalyst promoter on a layered support. (After Seah 1986,...

When the non-foam fillings are used as composite fillings ror upholstered seating or for mattresses and bed bases the multiple layer composite is treated as a single material and tested in its final form to BS 5852 part 2 or BS 6807 respectively. 

West PR, Davis GC, Regh KA. Contrast Enhancement Layer Compositions, Alkyl-nitrones, and Use, US Patent No. 5106723, April 21, 1992. 

The fact that LEIS provides quantitative information on the outer layer composition of multi-component materials makes this technique an extremely powerful tool for the characterization of catalysts. Figure 4.19 shows the LEIS spectrum of an alumina-supported copper catalyst, taken with an incident beam of 3 keV 4He+ ions. Peaks due to Cu, A1 and O and a fluorine impurity are readily recognized. The high intensity between about 40 and 250 eV is due to secondary (sputtered) ions. The fact that this peak starts at about 40 eV indicates that the sample has charged positively. Of course, the energy scale needs to be corrected for this charge shift before kinematic factors Ef/E-, are determined. 

In conclusion, LEIS is extremely surface sensitive and suitable for determining outer layer compositions of catalysts and alloys, provided that proper calibration can be achieved. The shape of the background contains information about the vertical distribution of elements in the surface region. 

Although the electrode performance can be improved by the introduction of compositional and microstructural gradients into the anode or cathode, the processing required to produce such graded layers also increases in complexity as the number of discrete layers increases, particularly when separate deposition and firing steps are required for each increment in layer composition or structure. 

Nickel (8) calculated the thickness of the proposed "residual layer" on albite from the mass of dissolved alkalis and alkaline earths released during laboratory weathering and the measured surface area, and determined that the thickness ranges from 0.8 to 8.0 nm in the pH range of natural surface waters. Although he interpreted his results differently, they anticipate later findings on the pH dependence of residual layer compositions (see below). 

Figure 3.42. Schematic representation of a double layer composite structure. Two substructures (1 and 2) are sketched. The composite structure (1 + 2) resulting from the mutual intermingling of the two substructures has a period corresponding to six subcells 1 commensurate to seven subcells 2.

The Kinetic Consequences of the Double Layer Composition on the Electron Transfer... 

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