Earing in cup drawing face-centered cubic single crystals and polycrystals

A simple model of flange behavior during cup drawing was used to predict the earing profile of deep-drawn cups. The relationship between yield surface shape and earing tendency was established, with plane stress yielding corresponding to no hold-down pressure on the flange and plane strain corresponding to no thickening. Using the Schmid law, the earing model was applied to the case of a single crystal in cube position and compared to Tucker’s well-known results.^[6] For the plane strain case, good agreement was obtained with the experiment; but for plane stress, the predicted profile did not agree with the experimental one. Using the Taylor/ Bishop and Hill (TBH) theory^[8,9] and measured crystallite orientation distribution functions (CODF), the model was applied to the case of high-purity aluminum sheet with various cold-rolling reductions (35, 60, 80, and 90 pct). The major experimental trends were again correctly predicted by the plane strain case.     

'Size leap' algorithm: an efficient extraction of the longest common motifs from a molecular sequence set. Application to the DNA sequence reconstruction.

We propose a new method, called 'size leap' algorithm, of search for motifs of maximum size and common to two fragments at least. It allows the creation of a reduced database of motifs from a set of sequences whose size obeys the series of Fibonacci numbers. The convenience lies in the efficiency of the motif extraction. It can be applied in the establishment of overlap regions for DNA sequence reconstruction and multiple alignment of biological sequences. The method of complete DNA sequence reconstruction by extraction of the longest motifs ('anchor motifs') is presented as an application of the size leap algorithm. The details of a reconstruction from three sequenced fragments are given as an example.     

Catalysis of linoleate oxidation by soluble chicken muscle proteins

A soluble fraction of a chickenMusculus gastrocnemius muscle was used to characterize the catalyst of linoleate oxidation. Separation of the chicken muscle extract into low (free metal) and high (protein) molecular weight fractions revealed that the molecular weight of the major catalyst of linoleate oxidation in chicken muscle extract was greater than 700 daltons. Catalysis of linoleate oxidation by the protein fraction exhibited a pH optimum of 5.9. Subjecting the protein fraction to heat treatments at increasing temperatures (30–90 C) decreased the catalysis of linoleate oxidation. Addition of two mM EDTA had no effect on the catalysis of linoleate oxidation. Cyanide (2 mM), glutathione (1 mM) and cysteine (1 mM) decreased the oxidation of linoleate by the protein fraction 21.0%, 22.9% and 29.0% respectively. Characterization of the oxidative catalyst in chicken muscle extract indicated that free metals and hemoproteins contribute to overall catalysis of linoleate oxidation but are not the sole catalysts. Heat inactivation of the oxidative catalyst and the observed pH optimum suggests that the unidentified catalyst is proteinacious and may be an enzyme.     

The gamma-ray-induced crosslinking of polyacrylamide

The gamma-ray-induced crosslinking of polyacrylamide was carried out under various conditions. The molecular weight of the polymer before inrradiation was found to be the most important factor for crosslinking. When polymers have low molecular weights such as 80,000, the intensity of radiation, the external pressure applied, and the water content of the polymer powder became important for crosslinking. Although the polycrylamide hydrogel can be obtained directly by irradiating the monomer, it was obtained more conveniently by the irradiation of monomer—polymer mixtures. The hydrogels obtained by the radiation with a dose of over 50 kgray, absorb water by 1000–1500 wt %.     

Kinetics of BaTiO3 and PbTiO3 Formation from Metallo-organic Precursors

Kinetics of BaTiO₃ and PbTiO₃ formation from metalloorganic precursors were studied. The fine grain size of the decomposed product and the greater degree of mixing led to very rapid kinetics of compound formation. The kinetics data were fitted to the Carter model for a diffusion-controlled process. Formation of PbTiO₃ was modeled as a two-stage process with a single activation energy, and the formation of BaTiO₃ as a single-stage process.     

Effect of spinneret hole diameter on the spinning and properties of acetate fibre

Conclusions The effect of the number and diameter of spinneret holes on hole clogging and the properties of acetate yarns has been investigated under manufacturing conditions.On reducing spinneret hole diameter and increasing the number of holes, the strength and fatigue properties are raised, but the elongation of acetate yarn is reduced.Translated from Khimicheskie Volokna, No. 1, pp. 29–30, January–February, 1986.     

The nature and role of incoherent interphase interfaces in diffusional solid-solid phase transformations

In this article, some views on the nature of incoherent interphase interfaces, and their role in the nucleation and growth processes governing the evolution of microstructure in solid-state diffusional transformations (reconstructive transformations), are explored. It is argued that essentially incoherent interfaces can be involved in the initiation and propagation of polymorphic transformations and massive transformations as well as in various precipitation phenomena in metallic and ceramic systems. Similar views have already been advanced earlier in connection with studies of massive transformations. Faceting along the interphase interface during nucleation and growth can derive from thermodynamic, kinetic, and crystallographic factors independent of the bicrystallography of the conjugate phases. This idiomorphic behavior can be relevant to both intergranular and intragranular phase formation. The concept of one-dimensional (1-D) commensuration of phases through plane edge-to-edge/row matching is an interesting extension of the classic ideas of coherency and bicrystallography and potentially important in characterizing the behavior of certain types of boundaries. However, the general importance of these geometrical relations in real and reciprocal space will depend on the depth of the energy wells in orientation space associated with these special boundaries. This article is based on a presentation made in the “Hume-Rothery Symposium on Structure and Diffusional Growth Mechanisms of Irrational Interphase Boundaries,” which occurred during the TMS Winter meeting, March 15–17, 2004, in Charlotte, NC, under the auspices of the TMS Alloy Phases Committee and the co-sponsorship of the TMS-ASM Phase Transformations Committee.     

Synthesis of minerals using alternative energy sources

A technology for the synthesis of synthetic minerals (using the example of spinels) using a low-temperature plasma flame is developed. The diagnostic properties of spinels are identified.