Materials Literature
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Abstract New and updated, this second edition of Protein Structure presents electrophoretic, chromatographic, and spectrophotometric techniques as well as including new chapters on the relatively sophisticated methods of mass spectrometry and ultracentrifugation. The emphasis is not on the technical aspects of the ins…
One-dimensional conductors are a long-standing topic of research with direct applications to organic conductors and mesoscopic rings. The discovery of the ceramic high-temperature superconductors has revitalized the interest in low-dimensional charge and spin fluctuations of highly correlated electron systems. Several…
Abstract The stability of proteins, especially enzymes, has long been a practical concern (1), because this is usually the factor that most limits their usefulness. There are two very different aspects of protein stability. One is the chemical stability of the covalent structure, which involves covalent changes and is…
The effects of mobility of small islands on island growth in molecular beam epitaxy are studied. It is shown that small island mobility affects both the scaling and morphology of islands during growth. Three microscopic models are considered, in which the critical island sizes are $i^*=1,2$ and 3 (such that islands of…
Abstract The commonest means of laboratory evaluation/screening of scale inhibitors for oilfield applications is by conducting scale inhibition jar tests. This paper focuses on several aspects concerning barium sulphate scale inhibition jar tests and highlights three particular factors which may influence the test out…
Abstract Paraffinic crude oils are often transported at conditions where heavy hydrocarbons contained in the oil may precipitate as a solid waxy material. This precipitation may plug the processing equipment. In the design of oil production facilities, it is therefore essential to be able to predict the conditions whe…
Introduction Alkalinity is an important parameter used to describe composition, buffer capacity and pH-behaviour of waters in many different fields of science. Although the alkalinity is widely applied, it seems to be a lot of confusion in connection with the concept, and it is often used incorrectly. One of the reaso…
G.M. Graham, SPE, M.M. Jordan, Heriot-Watt University, SPE, G.C. Graham, W. Sablerolle, Shell U.K. Exploration & Production, K.S. Sorbie, Heriot-Watt University, SPE, P. Hill, University of Manchester, and J. Bunney, SPE, Heriot-Watt University Abstract In this paper, results are presented which highlight the prob…
Abstract Downhole mineral scale prevention in oilfields is usually achieved through the use of chemical scale inhibitors applied in "squeeze" treatments. These species are thought to be retained in the reservoir formation by one of two main mechanisms, viz. adsorption and precipitation. In a previous modelling and exp…
We have cloned and sequenced genes for triosephosphate isomerase (TPI) from the gamma-proteobacterium Francisella tularensis, the green non-sulfur bacterium Chloroflexus aurantiacus, and the alpha-proteobacterium Rhizobium etli and used these in phylogenetic analysis with TPI sequences from other members of the Bacter…
Abstract One of the most common methods of preventing downhole and topside mineral scale formation in oilfields is through the use of chemical scale inhibitors. Several aspects of the brine composition may affect the performance of the various scale inhibitors used in oilfield applications and, in this paper, we will…
Trypsin and chymotrypsin have similar tertiary structures, although very different substrate specificities. Trypsin hydrolyzes peptides at Lys/Arg residues while chymotrypsin recognizes large hydrophobic residues. Recent work has shown that trypsin is not converted into a protease with chymotrypsin-like activity when…
We present a computer simulation study of orientational correlations in a molecular liquid approaching the isotropic-nematic transition, including the first calculation of the direct correlation function $c(1,2)$ in this regime. While the second-rank orientational correlation length diverges, the associated component…
Partially miscible binary liquids containing silica colloids show equilibrium phase boundaries and critical lines. The phase separation is ternary in nature, and measurements allow construction of the ternary phase prism for colloids dispersed in binary fluid mixtures. Comparison with earlier aggregation studies stron…
We report x-ray intensity fluctuation spectroscopy measurements of the equilibrium dynamics of polymer micelle liquids, composed of polystyrene-polyisoprene block copolymer micelles within a polystyrene homopolymer matrix. The equilibrium dynamics were investigated for times between one and several hundred seconds, an…
Combining the use of a UV storage ring free electron laser and of synchrotron radiation, a time resolved core level spectroscopy study has been performed on photoexcited Si(111)2×1 surfaces with subnanosecond resolution. This enabled us to measure band bending fluctuations, caused by surface carrier dynamics, during t…
Magnetic entropy change of La0.75Ca0.25MnO3 with different particle size has been investigated. Magnetic entropy change ∼4.7 J/kg K larger than that of Gd has been observed at 224 K under a magnetic field of 1.5 T in comparatively big particles. This phenomenon of large magnetic entropy change indicates that the perov…
The dynamics of single bubble sonoluminescence (SBSL) strongly depends on the percentage of inert gas within the bubble. We propose a theory for this dependence, based on a combination of principles from sonochemistry and hydrodynamic stability. The nitrogen and oxygen dissociation and subsequent reaction to water sol…
Direct experimental evidence is presented for the existence of localized excitations on fractal supermolecular structures that may serve as photonic antenna systems. For one dendrimer family the electronic spectra show no redshift with system size, indicating that the excitations are localized at the nodes of the Cayl…
The crystal structure of potassium tungsten tetraselenide is based on isolated, slightly distorted WSe4 tetrahedra joined via K+ ions. The compound is isotypic with the previously reported Rb and Cs analogues and crystallizes in the β-K2SO4 structure type.