REFRACTORIES FOR USE IN SULPHATE-RECOVERY FURNACES OF THE PULP AND PAPER INDUSTRIES*

The paper gives a short review of the soda-recovery methods used in the Kraft process. The tests made to determine the relative merits of different refractories were (1) P.C.E. determinations of soda-refractory mixtures, (2) simulative-service slag tests, and (3) petrographic analyses. Tests indicate that resistance is produced by (1) an impervious crystalline structure, such as soapstone for the low temperatures and electro-cast mullite for the high temperatures, or (2) chemical inertness in contact with soda, such as is found with purer forms of magnesia.     

T-cell receptors in channel catfish: structure and expression of TCR alpha and beta genes

Herein are reported full length cDNA sequences for TCR alpha- and beta-chains of the channel catfish. Included are sequences belonging to four Valpha and six Vbeta families which share hallmarks in common with the Valpha and Vbeta genes of other species. Similar to the situation in other vertebrates, the catfish Calpha and Cbeta sequences exhibit distinct immunoglobulin, connecting peptide, transmembrane and cytoplasmic domains. However, the catfish TCR Calpha and Cbeta regions are shorter than those of mammals and the catfish Cbeta chain lacks a cysteine in its connecting peptide region. Two different catfish Cbeta cDNA sequences were identified, suggesting the existence of either two Cbeta loci or allotypes. Based on Southern blot analyses, each of the catfish TCR gene loci appear to be arranged in a translocon (as opposed to multicluster) organization with multiple V elements and a single or few copies of C region DNA. At the deduced amino acid level, the catfish Cbeta sequence exhibits 42% identity with the Cbeta of Atlantic salmon, 41% identity with the Cbeta of rainbow trout and 26% identity with Cbeta of the horned shark. The catfish Calpha amino acid sequence exhibits 44 and 29% identity with Calpha of the rainbow trout and southern pufferfish, respectively. TCRalpha and beta messages are selectively expressed and rearranged in a catfish clonal cell line that appears to be of the T lineage. This TCR alpha/beta expressing clonal lymphocyte line, designated 28S.1, has T-cell like function in that it constitutively produces a supernatant factor(s) with growth promoting activity. These findings should facilitate functional studies of fish TCRs and T cells in ways not previously possible with other 'lower' vertebrate models.     

The determinants of the vertical boundaries of the construction firm

In the last few years, transaction cost economics has become a popular theory within the construction research community. This approach has been singularly applied as a means to explain and predict phenomena concerning the construction firm, including its vertical boundaries. However, this is at a time when the chief proponents of transaction costs are urging researchers to take a pluralistic stance in relation to the theory of the firm. The aim of this paper is to develop a pluralistic approach to the vertical boundaries of the construction firm. In order to achieve this, an integrative framework is described, based on the development of the efficient boundaries problem and the capabilities approach to vertical integration. Specifically, this framework draws on the complementary strengths of transaction cost economics and the resource‐based view. It is concluded that the potential relative merits of theoretical pluralism, in terms of the vertical boundaries of the construction firm, are sufficient grounds to motivate empirical testing of the predictions associated with the integrative framework of vertical integration presented.     

Fast lithium-ion conducting thin-film electrolytes integrated directly on flexible substrates for high-power solid-state batteries

By utilizing an equilibrium processing strategy that enables co-firing of oxides and base metals, a means to integrate the lithium-stable fast lithium-ion conductor lanthanum lithium tantalate directly with a thin copper foil current collector appropriate for a solid-state battery is presented. This resulting thin-film electrolyte possesses a room temperature lithium-ion conductivity of 1.5 × 10(-5) S cm(-1) , which has the potential to increase the power of a solid-state battery over current state of the art.     

Time-dependent voltage generated by flux motion across a superconducting strip

A brief review is given of the theory predicting that the instantaneous voltage generated by single-quantum vortices or multiquanta flux tubes moving through a superconducting specimen depends upon both the specimen shape and the spatial configuration of the measuring circuit. This theory is then applied to obtain the voltage pulses expected from two different measuring circuits attached to a superconducting strip. The time-dependent voltage is predicted to be proportional not only to the vortex or flux-tube velocity but also to a geometry-dependent function of the position of the vortex or flux tube relative to the measuring circuit.Operated for the U.S. Department of Energy by Iowa State University under contract No. W-7405-Eng-82. This research was supported by the Director for Energy Research, Office of Basic Energy Sciences, WPAS-KC-02-02-03, and by the NATO Research Grants Program.     

Meissner shielding currents and magnetic flux penetration in thin-film superconductors

We have observed the magnetic flux penetration at 4.2 K into superconducting lead films of about 4 µm thickness using a high-resolution magnetooptical technique. The specimens had the shape of small squares or long strips. In increasing magnetic field it was found that magnetic flux starts to penetrate into the bulk of the specimens in the form of flux tubes containing about 60 flux quanta. For the samples with the strip geometry the magnetic fieldH*, at which flux penetration into the bulk sets in, was investigated in the presence of an external electrical currentI along the strip superimposed on the Meissner shielding currents. The fieldH* was found to decrease linearly with increasing transport currentI. The magnetic field near a long superconducting cylinder in the presence of both a transverse applied magnetic field and an applied electrical current parallel to the cylinder axis has been calculated. The calculation is valid for a cylinder of elliptical cross section, which approximates a long, flat strip. The experimental observations for the slope H*/I are in good agreement with the calculations.Work performed in part in the Argonne National Laboratory and in part in the Ames Laboratory of the U.S. Atomic Energy Commission.     

Control of Microstructure and Orientation in Solution-Deposited BaTiO3 and SrTiO3 Thin Films

Columnar and highly oriented (100) BaTiO₃ and SrTiO₃ thin films were prepared by a chelate-type chemical solution deposition (CSD) process by manipulation of film deposition conditions and seeded growth techniques. Randomly oriented columnar films were prepared on platinum-coated Si substrates by a multilayering process in which nucleation of the perovskite phase was restricted to the substrate or underlying layers by control of layer thickness. The columnar films displayed improvements in dielectric constant and dielectric loss compared to the fine-grain equiaxed films that typically result from CSD methods. Highly oriented BaTiO₃ and SrTiO₃ thin films were fabricated on LaAlO₃ by a seeded growth process that appeared to follow a standard "two-step" growth mechanism that has been previously reported. The film transformation process involved the bulk nucleation of BaTiO₃ throughout the film, followed by the consumption of this matrix by an epitaxial overgrowth process originating at the seed layer. Both BaTiO₃ and PbTiO₃ seed layers were effective in promoting the growth of highly oriented (100) BaTiO₃ films. Based on the various processing factors that can influence thin film microstructure, the decomposition pathway involving the formation of BaCO₃ and TiO₂ appeared to dictate thin film microstructural evolution.