Direct reduction process using fines and with reduced CO2 emission

Abstract

A direct reduction process for refractory oxides and a life cycle analysis comparison with conventional pelletising and sintering process for chargechrome are presented. The new route has potential to reduce the environmental impact of the ferroalloy industry and to extend the use of nonrenewable resources by utilising waste that is not economically recoverable by conventional technologies; increasing metal recoveries; significantly reducing CO₂ emissions; reducing or eliminating the use of coke; and reducing electricity consumption during smelting.     

Study on percutaneous rate of P-aminobenzoates using molecular orbital method

The use of a dome osteotomy in the treatment of infantile tibia vara is reportedly associated with insufficient intraoperative assessment of the correction achieved. This article discusses a method to overcome this problem and the long-term advantages of using a dome osteotomy in the treatment of this disease.     

Ab initio phase determination and phase extension using non-crystallographic symmetry

Non-crystallographic symmetry (NCS) can be used to improve, extend or find ab initio phases to be associated with a set of observed structure amplitudes, resulting in an interpretable electron-density map. The simplest application is merely to improve the accuracy of the phases by cyclically averaging the electron density, Fourier back-transformation of the modified map, and recomputing a new map with the newly found phases. The first sophistication of this procedure is to phase extend, in successive small steps, the currently available phase information to higher resolution, where only observed amplitudes were previously available. A further sophistication is to initiate the phase extension from very low resolution where a simple geometric model, or an electron microscope image, would be consistent with the chosen resolution. A number of recent examples of virus structure determination exist where such ab initio phasing was successful. The ultimate ab initio phase determination would be to extend phases given only an estimate of the F(000) term.     

Investigation of the solution structure of chymotrypsin inhibitor 2 using molecular dynamics: comparison to x-ray crystallographic and NMR data

The native solution structure and dynamics of chymotrypsin inhibitor 2 (CI2) have been studied using a long (5.3 ns) molecular dynamics (MD) simulation without any imposed restraints. The majority of the experimentally observed spin-spin coupling constants, short- and long-range nuclear Overhauser effect (NOE) cross peaks and the amide hydrogen exchange behavior were reproduced by the MD simulation. This good correspondence suggests that the major structural features of the protein during the simulation are representative of the true protein structure in solution. Two water molecules formed hydrogen bond bridges between beta2 and beta3, in agreement with X-ray crystallographic data and a recent reassessment of the solution structure using time-averaged NMR restraints during MD refinement. The active-site loop of the protein displayed the greatest structural changes and the highest mobility. When this loop region was excluded, the average Calpha r.m.s. deviation of the simulated solution structures from the crystal structure was approximately 1.5 Angstrom from 0.5 to 5.3 ns. There is structural heterogeneity in particular regions of the NMR-derived solution structures, which could be a result of imprecision or true internal motion. A study of the distribution of mobility through the protein allows us to distinguish between these two alternatives. In particular, deviations in the active-site loop appear to be a result of heightened mobility, which is also supported by good correspondence between calculated and experimental S2 N-H order parameters. On the other hand, other ill-defined regions of the NMR-derived structures are well defined in the simulation and are probably the result of a lack of structural restraints (i.e. NOEs), as opposed to reflecting the true mobility.     

Proton-induced x-ray emission analysis of single human hair roots

Collimated beams of 3.75 million electron volt protons were used to examine a 2-millimeter length of the root end of human hair; the concentrations of some hair root elements were correlated with the results of standard clinical assays of blood samples. The technique should be useful for the analysis of micro amounts of biological tissue.