General Electric (New Zealand)

A general expression which can be used either for predicting the average volumetric concentration or for analyzing and interpreting experimental data is derived. The analysis takes into account both the effect of nonuniform flow and concentration profiles as well as the effect of the local relative velocity between the phases. The first effect is taken into account by a distribution parameter, whereas the latter is accounted for by the weighted average drift velocity. Both effects are analyzed and evaluated. The results predicted by the analysis are compared with experimental data obtained for various two-phase flow regimes, with various liquid-gas mixtures in adiabatic, vertical flow over a wide pressure range. Good agreement with experimental data is shown.

ABSTRACT A generic transurantc (TRU) element extraction/recovery process was developed based on the use of octyl(phenyl)-N,N-diiso-butylcarbamoylmetliylphosphine oxide, 0φD(iB)CMPO, dissolved in PUREX process solvent (tribntyl phosphate, TBP, in normal paraffluic hydrocarbon, NPH). The process (called TRUEX) is capable of reducing the TRU concentration by many orders of magnitude In waste solutions containing a wide range of nitric acid, salt, and fission product concentrations. A major feature of the process is that it is readily adaptable for waste processing in existing fuel reprocessing facilities. Notes *Work performed under the auspices of the Office of Basic Energy Sciences, Division of Chemical Sciences, U. S. Department of: Energy under contract number W-31-109-ENG-38. Additional informationNotes on contributorsGeorge F. Vandegrift Chemical. Technology Division.

Abstract A new approach is developed for predicting strain-controlled, low cycle fatigue life at elevated temperature using a proposed energy measure of fatigue damage. This measure of damage, defined as the net tensile hysteretic energy of the fatigue cycle, can be approximated by the damage function σTΔεp, where σT is the maximum stress in the cycle and Δεp is the inelastic strain range. The damage function is applied to predicting effects of hold time and frequency, when time-dependent damage occurs, through failure relations incorporating a variation of Coffin's frequency modified approach. Failure equations are developed for two postulated categories of time-dependent damage.

Abstract One of the major difficulties of modelling fluid flow processes in hard‐rock geologies is the complex nature of the porosity systems. Hydraulic behaviour in these rock masses is characterized by both porous and fractured interflow zones. Traditionally, fractured‐porous rocks have been modelled as an equivalent porous medium or as a system of fractures separated by impermeable blocks. A new method is proposed that unifies these two approaches for modelling fluid flow processes in fractured‐porous media. The basic idea is to use a combination of isoparametric elements for the porous zones and line elements for the fractures. The coupling between the governing equations for each element type is achieved using the superposition principle. The effectiveness of the new approach is demonstrated by comparing numerical solutions with known solutions for problems of flow and solute transport in fractured‐porous media.

Description This publication is divided into five major subject areas: Creep and Swelling; Microstructural Development; Pressure Vessel Steels; Mechanical Properties; Charged Particle Irradiation; Theory of Radiation Effects.

The Ladolam hydrothermal system, on Lihir Island, Papua New Guinea, hosts one of the youngest and largest gold deposits in the world. Several deep (more than 1 kilometer) geothermal wells were drilled beneath the ore bodies to extract water at >275 degrees C and to facilitate open-pit mining. Using a titanium down-hole sampler, we determined that the deep geothermal brine of magmatic origin contains approximately 15 parts per billion gold. At the current gold flux of 24 kilograms per year, this deposit could have formed within approximately 55,000 years. The combination of sustained metal flux and efficient metal precipitation led to the formation of a giant hydrothermal gold deposit in a short period.

An AISI 4340 Steel (325 BHN) was machined at various speeds up to 2500 m/min (8000 SFPM). Longitudinal midsections of the chips were examined metallurgically to delineate the differences in the chip formation characteristics at various speeds. Chips were found to be continuous at 30 to 60 m/min (100 to 200 SFPM) but discontinuous below this speed. Instabilities in the cutting process, leading to different types of cyclic chip formations, were observed at cutting speeds above 60 m/min (200 SFPM). Fully developed catastrophic shear bands separated by large areas (segments) of relatively less deformed material, similar to that when machining titanium alloys, were observed in the chips at cutting speeds above 275 m/min (800 SFPM). The intense shear bands between the segments appeared to have formed subsequent to the localized intense deformation of the segment in the primary shear zone. As the cutting speed increases, the extent of contact between the segments is found to decrease rapidly. At speeds of 1000 m/min (3200 SFPM) and above, due to rapid intense, localized shear between the segments, these segments were found to separate completely as isolated segments instead of being held intact as a long chip. The speed at which this decohesion occurs was found to depend upon the metallurgical state of the steel machined and its hardness. As in the case of machining titanium alloys, the deformation of the chip as it slides on the tool face, i.e., “secondary shear zone,” appeared to be negligible when machining this AISI 4340 steel at high speed. Based on the metallurgical study of the chip and the similarities of machining this material at high speed and that of titanium alloys at normal speed, a cyclic phenomenon in the primary shear zone is identified as the source of instability responsible for the large-scale heterogeneity and a mechanism of chip formation when machining AISI 4340 steel at high speed is proposed.

Abstract This paper presents a method of computing the factor of safety of a structural member with reference to a stated life, when operating under stress at high temperature when the temperature varies or when the stress varies moderately according to some definite pattern. The formulas presented herein are based on the supposition that the expenditure of each particular fraction of the life span at elevated temperature is independent of and without influence upon the expenditure of all other fractions of the life to rupture. The author makes no claim that this assumption is wholly true. The suggested procedure is offered simply to provide a means for making engineering estimates with some greater validity than always to assume that the worst conditions are present all the time. The desirability of taking account of certain additional influences which may differ from one material to another is recognized.

Size exclusion chromatography (SEC) was used to determine the viscosity radii of equivalent spheres for proteins covalently grafted with poly(ethylene glycol) (PEG). The viscosity radius of such PEGylated proteins was found to depend on the molecular weight of the native protein and the total weight of grafted PEG but not on PEG molecular weight, or PEG-to-protein molar grafting ratio. Results suggest grafted PEG's form a dynamic layer over the surface of proteins. The geometry of this layer results in a surface area-to-volume ratio approximately equal to that of a randomly coiled PEG molecule of equivalent total molecular weight. Two simple methods are given to predict the viscosity radius of PEGylated proteins. Both methods accurately predicted (3% absolute error) the viscosity radii of various PEG-proteins produced using three native proteins, alpha-lactalbumin (14.2 kDa MW), beta-lactoglobulin dimer (37.4 kDa MW), and bovine serum albumin (66.7 kDa MW), three PEG reagents (2400, 5600, and 22500 MW), and molar grafting ratios of 0 to 8. Accurate viscosity radius prediction allows calculation of the distribution coefficient, K(av), for PEG-proteins in SEC. The suitability of a given SEC step for the analytical or preparative fractionation of different PEGylated protein mixtures may therefore be assessed mathematically. The methods and results offer insight to several factors related to the production, purification, and uses of PEGylated proteins.

Abstract The Griffith-model of brittle fracture of elastic solids and the model by Irwin and Orowan for the brittle fracture of elastic-plastic solids predict the propagation of cracks on the basis of energy supplied by the work of externally impressed forces and by the change of strain energy. Previous discussions have neglected the three-dimensional viewpoint and the body forces. Since the Irwin method of fracture-strength analysis has become of increased interest, especially with respect to rotor fracture, a general analysis of energy supply is presented. The analysis uses Clapeyron’s theorem and Betti’s reciprocal theorem. One of the results is that the energy supplied for crack extension equals the strain energy of the difference of the two stress fields before and after crack extension.

ABSTRACT The solubility of phytate and protein in soy extracts as influenced by pH, NaCl, calcium and EDTA was measured. The behavior of phytate is explained in terms of its binding to calcium‐magnesium and/or to proteins. Three processes for preparing low‐phytate soy protein products were derived from this theory, at both the laboratory and pilot plant scale. The nutritional properties of isolates prepared with these processes were examined.

All data available in the literature regarding oxygen activities and composition limits for the wustite phase were analyzed critically. The most reliable activity data were collected into a composite in which (1) the partial molal free energy of oxygen varied linearly with composition and reciprocal temperature and (2) the partial molal enthalpy and entropy of oxygen varied linearly with composition and were independent of temperature. These linear variations of the thermodynamic properties are inconsistent with the presence of additional phases which have been reported within the wustite phase field. The composition limits of the wustite phase, which were computed from the composite, were in excellent agreement with Darken and Gurry's original phase diagram.

A mass transport equation which takes into account parallel diffusion paths for both anions and cations was derived and applied to the diffusional creep of polycrystalline ionic solids. From the results of the analysis, several limiting conditions were found for grain‐boundary‐ and lattice‐diffusion‐controlled kinetics. These conditions depend on temperature, grain size, and type and concentration of cation impurities. Examples of these limiting situations are given for the creep of polycrystalline Fe‐doped MgO and transition‐metal‐doped Al 2 O 3 . Summary A mass transport equation which takes into account parallel diffusion paths for anions and cations was derived and applied to the diffusional creep of polycrystalline ionic solids. The effect of grain size and cation impurities of variable valence in solid solution on the relative contributions of lattice and grain‐boundary diffusion of different ionic species in polycrystalline MgO and Al 2 O 3 was examined. Depending on the temperature, grain size, impurity level, and O 2 partial pressure, several limiting conditions were found: Limit I: At very small grain sizes and reasonably small cation lattice diffusivities the creep rate will be controlled by the slower‐moving ion in the grain‐boundary regions (i.e. Coble creep). Limit II: For intermediate grain sizes and cation lattice diffusivities the creep rate will be controlled by cation lattice diffusion when anion transport is significantly faster near grain boundaries than in the lattice (i.e. Nabarro‐Herring creep). Limit III: For an appropriate combination of large grain size and high cation lattice diffusivity the creep rate will be controlled by anion boundary diffusion (i.e. Coble creep). Well‐defined examples of limits I and II have been observed in the creep of Fe‐doped polycrystalline MgO, and tentative evidence exists for limit III. Most results of studies of creep in polycrystalline Al 2 O 3 (doped and undoped) fall within limit II, with some overlap with limit III. The model developed in the present work explains much of the data in the literature in which creep rates correspond to cation lattice mobilities. It is concluded that in the creep of polycrystalline ionic solids anion transport near grain boundaries is rapid and can, in some circumstances, be rate‐controlling. It should also be possible to apply this model to sintering and thermal‐grooving data for such systems, particularly for Al 2 O 3 , in which cation lattice diffusion is frequently observed to be rate‐controlling. 32

A method is presented for predicting the performance of modern steam turbine-generator units designed for high efficiency levels. This method is based on recent developmental and analytical results. The necessary curves, tables, and instructions are provided for the application of the method to a large variety of units of various kilowatt ratings, types, and steam conditions. Relative heat-rate curves are presented and mathematical expressions are provided for computer applications.

Snapper ( Chrysophrys auratus ) is an important coastal fish species in New Zealand for a variety of reasons, but the large amount of research conducted on snapper has not been reviewed. Here, we review life history information and potential threats for snapper in New Zealand. We present information on snapper life history, defining stages (eggs and larvae, juvenile and adult), and assess potential threats and knowledge gaps. Overall we identify six key points: 1. post‐settlement snapper are highly associated with certain estuarine habitats that are under threat from land‐based stressors. This may serve as a bottleneck for snapper populations; 2. the largest knowledge gaps relate to the eggs and larvae. Additional knowledge may help to anticipate the effects of climate change, which will likely have the greatest influence on these early life stages; 3. ocean acidification, from land‐based sources and from climate change, may be an important threat to larval snapper; 4. a greater understanding of population connectivity would improve certainty around the sustainability of fishery exploitation; 5. the collateral effects of fishing are likely to be relevant to fishery productivity, ecosystem integrity and enduser value; 6. our understanding of the interrelationships between snapper and other ecosystem components is still deficient.

Magneto-optical imaging was used to visualize the inhomogeneous penetration of magnetic flux into polycrystalline TlBa2Ca2Cu3Ox films with high critical current densities, to reconstruct the local two-dimensional supercurrent flow patterns and to correlate inhomogeneities in this flow with the local crystallographic misorientation. The films have almost perfect c-axis alignment and considerable local a- and b-axis texture because the grains tend to form colonies with only slightly misaligned a and b axes. Current flows freely over these low-angle grain boundaries but is strongly reduced at intermittent colony boundaries of high misorientation. The local (<10-micrometer scale) critical current density Jc varies widely, being up to 10 times as great as the transport Jc (scale of approximately 1 millimeter), which itself varies by a factor of about 5 in different sections of the film. The combined experiments show that the magnitude of the transport Jc is largely determined by a few high-angle boundaries.

This paper presents theoretical, simulation, and experimental study of the brushless doubly fed twin stator induction generator (BDFTSIG) dynamics under vector control based on the orientation on the power machine stator flux. A complex transfer function is derived which links the control current and power winding current space vectors in the field coordinates. Based on this result, the transient response of the BDFTSIG to step changes in the control current is examined theoretically. The oscillatory transients are explained in detail and linked to control flux transients triggered whenever operation point of the generator is changed. Furthermore, BDFTSIG operation with closed loop control of the power machine active and reactive powers is examined theoretically and experimentally. It is shown that in the closed loop operation, the system damping may be reduced so that the PI controller gains must be properly selected to achieve a good transient response.

Abstract Absorption spectra of solutions in acetonitrile of tetra (ethyl) ammonium salts of UCl6 --, UBr6 --, UI6 --, NpCl6 --, NpBr6 --, PuCl6 -- and PuBr6 -- show three types of bands arranged according to increasing half-width: (1) internal 5f q transitions showing a large nephelauxetic effect, the wavenumbers in the hexabromides being some 3–5 per cent smaller than of the corresponding hexachlorides; (2) 5f q →5f q-16d transitions indicating that the 5f→6d orbital energy differences are roughly constant as function of q in contrast to the strong increase in the aqua ions; (3) π 245f q →π 235f q+1 electron transfer bands indicating that the optical electronegativities x opt (corrected for spin-pairing energy and certain effects of L, S, J splitting) are 1·5 for U(IV), 1·75 for Np(IV) and 2·05 for Pu(IV). Further on, the charge separation effects on electron transfer bands are discussed with special regard to uranyl iodide complexes. Additional informationNotes on contributorsChr. Klixbüll Jørgensen The work done at this laboratory was performed under contract No. AT(45-1)-1350 for the U.S. Atomic Energy Commission.

Abstract A tentative test procedure for the determination of the plane strain-crack growth resistance JI-R curve for metallic materials is presented. This procedure was prepared by a Working Group of ASTM Committee E24.08.03. It was evaluated with a round robin test program on HY130 steel, conducted in 1980 to 1981. The results of the testing program were reported in a companion paper, and the experiences were incorporated in this procedure. The procedure is written for the elastic compliance method of developing the plane strain JI-R curve. Recommended specimens are the pin-loaded compact and the three-point bend specimens. Details regarding apparatus, specimen preparation, test system calibration, testing, calculation of J and crack extension, and data qualification are specified.

Abstract Measurements of apparent resistivity made using the bipole-dipole method depend upon the location and orientation of the current source relative to the body under study. Although it has been recognized that this dependence on orientation can be partially overcome by use of two current bipoles with different orientations, no agreement on the method of analysis of multiple source surveys has been reached. The most general form of presentation of such results is an apparent resistivity tensor. Various rotation invariants derived from the apparent resistivity tensor can be regarded as mean values of apparent resistivity, independent of the direction of the electric field, thus greatly reducing the "false anomalies" typical of single-source bipole- dipole survey results. Two of the tensor invariants obey the principle of reciprocity: if the roles of the current and potential electrodes are interchanged, the invariants are unchanged. The properties of the apparent resistivity tensor are demonstrated for selected simple models. For a horizontally layered medium, when the receiver array is far from the current source, the tensor is symmetric and has invariants which depend only on the distance from the current source. The extreme values of apparent resistivity occur when the electric field vector is tangential and radial relative to the current source. These extreme values correspond to the Schlumberger apparent resistivity and the "polar" dipole apparent resistivity, respectively.