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Phelps Dodge Mining Company (Phelps Dodge) is operating a pressure-leach vessel (PLV) for copper concentrates at the Bagdad Mine facility in Arizona. This single PLV unit was engineered and constructed based on continuous laboratory testing, on reaction chemistry and kinetics and on available pressure-vessel technology. The challenge of designing for optimum process retention time, agitation, oxygen mass transfer, temperature and pressure are reviewed in this paper. The PLV interior lining, agitation equipment and compartment configuration chosen for the PLV are also reviewed.

There have beert many changes during the past decade in the concepts of development planning and in the roles of sanitary engineers and other Professionals in the planning process. Although most professional knowledge is applied to solving environmental problems of communities, engineers are being called upon, more and more, to become involved in the comprehensive development planning of whole river basins, provinces, and even countries. In this broader planning effort engineers are also concerned with the water needs of economic sectors such as manufacturing, which is discussed here.

A spectrophone and a CO_2 laser source were used to determine the absorption coefficients of NH_3 at seventy-seven laser lines in the 00°1–02°0 band at 9.4 μm and the 00°1–10°0 band at 10.4 μm. The NH_3 was buffered with N_2 to 1 atm at 295 K; its concentration ranged from 30 ppm to 200 ppm. The absorption coefficients and their probable errors are tabulated.

Estradiol has been documented to inhibit the oxidation of low density lipoprotein (LDL). We show that physiological concentrations of estradiol do not inhibit the oxidation of LDL by copper. LDL samples isolated from a) premenopausal and postmenopausal women and from b) women at different time periods during their menstrual cycle, who differ vastly in plasma estradiol levels, were also oxidized at the same rates by copper. In contrast, LDL samples isolated from c) women who were hyperstimulated during in vitro fertilization (IVF), with estradiol concentrations above 2000 pg/ml, were resistant to oxidation by copper. However, these LDL samples were also oxidized at a higher rate by peroxidases. More importantly, subjects with high estradiol levels also showed an increase in myeloperoxidase (MPO) protein in the plasma. Based on these results, we conclude that at physiologic concentrations, it is unlikely that estradiol could act as an antioxidant. In fact, the ability of estradiol to induce MPO and become a prooxidant might instead suggest that MPO-mediated oxidative clearance of LDL from plasma by liver might favorably influence the outcome of atherosclerosis.

The Second National Assessment of Water and Related Land Resources indicates that, although reliance on public water supplies by industry will increase, the growth of recycling will reduce industrial water use.

Induced hyperferremia enhanced local Klebsiella infection, with and without a surgical suture as a test foreign body. Both bacterial proliferation and death occurred often in mice treated with ferric ammonium citrate. Muramyl dipeptide significantly protected animals from local bacterial growth, death, and, to some extent, bacteremia.

The concentration of chlorophenolic compounds in suspended sediments was determined at four sites located on the upper Fraser River in British Columbia, Canada. One site was located upstream from the five pulp mills on the Fraser River, while the remaining three sites were located downstream from these mills. Suspended sediment samples were collected using a continuous flow centrifuge during the fall low flow and winter (under ice) periods. Nineteen chlorophenolic compounds were detected in samples collected from the downstream sites, with 4,5-dichlorocatechol, 3,4,5-trichlorocatechol and 3,4,5,6-tetrachlorocatechol measured in the highest concentrations. Samples collected under winter low flow conditions consistently had higher concentrations of chlorophenolics than samples collected under fall flow conditions. This is likely the result of a decrease in both the river flow and the background suspended sediment concentration during the winter low flow period.

Abstract: This paper reports on the design, calibration, and accuracy check of a six-load component dynamometer incorporating octagonal strain rings. The dynamometer was designed using the computer-aided design procedure described in an earlier article by Kroencke and Hull1. The accuracy check revealed inaccuracy which was traced to non-linearity in cross-sensitive load-strain relations. Interface plate compliance was determined as the cause of the nonlinearity by means of finite-element analysis. From this analysis two methods for avoiding the nonlinearity were identified. One is to insure that the interface plates are much stiffer than the octagonal strain rings and the other is to connect the interface plates to the environment so that the boundary conditions are identical for both plates.

Absorption coefficients have been measured for ethylene in the 9- and 10-μm range with a photoacoustic spectrophone. Pressure dependency in the 10P C^12O_2^16 range was studied for various concentrations of ethylene. Comparisons of the data with other measurements of both atmospheric and pressure-dependent absorption coefficients were also made, and a method for relating ethylene pressure-dependency data on absorption to molecular structure was examined. Typical discrepancies between up to six independent measurements of ethylene absorption were 38.1% at the 10-μm R(20) line, 4.4% at the 10-μm P(18) line, and 18.5% at the 10-μm P(26) laser line.

D. Bloomfield and R. Brewer from the Building Research Establishment, I. Cooper and S. Lera from Eclipse Research Consultants and B. Stringer from the Energy Technology Support Unit at the Harwell Laboratory describe the UK experience gained by participation in the International Energy Agency programme on passive solar gain and hybrid low-energy building. It concludes that much work is still to be done on modelling, that presentation of design guidelines needs to be appropriate to the audience, and building practice and occupant behaviour should not be underestimated when collaborating on international ventures.

The role of micromorphology (thin section microscopy) in chemical-mineralogical studies of soils is discussed in relation to mineral weathering, formation of concentrations of constituents (pedological features), and the effects of such concentrations on the chemistry of the soil profile. In mineral weathering, micromorphology is used to ascribe specific secondary minerals to their “parent” primary minerals, and to record the optical properties of weathered mineral grains. In pedological features, it is used to record the patterns of concentration of particular constituents. In both studies, it can be used subsequently to correlate similar features between different soil profiles, and so aid in extrapolation of data regarding chemical processes and conditions of formation obtained from specific detailed studies. The effect of pedological features on the chemistry of soil materials through their effect on the microhydrology of the profile and on the chemistry of the soil solution is apparent in a general way, but specific data are lacking. It is inferred that the full potential of micromorphology in such studies has not been realized because of the general lack of attempts to correlate microscopic data with chemical and mineralogical data.

An alpine humus soil profile has been examined in the field, in thin section and by X-ray diffraction. The presence of a stone line and the sudden change in characteristics across the stone line, including particle size distribution, degree of exfoliation of the micas, major mineral composition, and clay mineralogy suggest that this is a polygenetic profile consisting of two soil stratigraphic units. There has been little pedological reorganization within either unit, soil formation consisting essentially of in situ weathering, removal of soluble constituents, and accumulation of organic matter, with some biological activity, in the upper unit. It is shown that gibbsite derived from weathering of feldspar is a major component of the clay fraction, especially in the lower unit. The clay mineralogy is considered in relation to proposed mineral weathering sequences and weathering in a yellow podzolic soil.

Five soil profiles on alluvial terraces in the Macleay River Valley, N.S.W., have been studied to determine changes in soil development with increasing age. The criteria used were mainly macromorphology, micromorphology (basic fabric, evidence of weathering of lithorelicts and biotite, and depth functions of illuviated clay), depth functions of grain-size distributions, and clay mineralogy. The evidence suggests that the four youngest soil profiles represent successive stages of profile development by weathering for the most part and, to a lesser extent, formation of an horizon of illuviated clay; data for the oldest soil indicate a different history of profile development.

The circumstances of the setting up of the Sub-Committee for Soil-Stratigraphic Nomenclature are set out in the introduction to the report which follows. A draft report prepared by the Sub-Committee was considered by the Stratigraphic Nomenclature Committee at its meeting at Adelaide in August 1969. As a result of the decisions at that meeting copies of the draft report were sent to all divisional subcommittees of the Stratigraphic Nomenclature Committee so that they could submit their comments to the convener to pass on to the Soil-Stratigraphic Nomenclature Sub-Committee for further consideration. The Sub-Committee then modified the report in accordance with the comments received. Further comment is invited, and it is hoped that as a result it will be possible for provision for Soil-Stratigraphic units to be included in the next edition of the Code of Stratigraphic Nomenclature. The Society owes a considerable debt to the members of the Sub-Committee for Soil-Stratigraphic Nomenclature, Dr Brewer, Dr Crook and Mr Speight, for the time and trouble which they have taken in trying to evolve an acceptable system for nomenclature of Soil-Stratigraphic units.N. H. Fisher, Convener, Stratigraphic Nomenclature Committee.

Summary Comparative rests are reported on reinforced concrete beams without shear reinforcement made with different types of aggregate: two types of lightweight aggregate and one gravel aggregate were used. Other variables were the concrete strength and the type of reinforcement. The principal results of the tests were as follows. (1) For concretes of similar cube strength, the average diagonal cracking loads of the beams made with lightlveight aggregate were lower than those of the beams made with gravel aggregate. (2) The average diagonal cracking loads of beams reinforced with ordinary mild-steel were higher than those of the corresponding beams reinforced wirh an equivalent area of cold-worked deformed hars. (3) The diagonal cracking load increased with increasing concrete strength, the rate of increase heing similar for all three types of concrete.

After briefly reviewing previous work in this field, the authors propose that rupture of the chip work contact (to give a discontinuous chip) is governed by a limiting shear strain energy condition. Assuming that shear stress and strain at rupture are dependent on the compressive normal stress, a criterion for the direction of the rupture plane is deduced. Using some results given by Field and Merchant, the authors then compare their calculated direction of rupture with that experimentally observed. Some indication that the agreement is not entirely fortuitous is afforded by checking the calculated shear strain energy at fracture with that calculated from force and chip measurements.

The micromorphology of a yellow earthy sand profile (P549) from the Western Australian sand plains, originally reported in the Handbook of Australian Soils (Stace et al., 1968, pp. 48-50), has been re-examined in more detail and compared with samples of indurated lateritic mottled-pallid zone material. The evidence, based on field relationships, and on a comparison of the fabric of the lateritic material with the glaebules in the yellow sand profile, strongly supports the hypothesis that the upper zone of the sand plains consists of a transported sedimentary (colluvial) deposit derived by erosion from an older lateritic profile. The profile examined is derived from indurated mottled-pallid zone material. It is unnecessary to postulate repeated episodes of erosion and deposition to explain the 'sandy' nature of the profile which, in fact, contains a high proportion of argillaceous glaebules. The profile is 'young' at least in the sense of profile development.

Recognition of time as an important soil-forming factor suggests the importance of soil stratigraphy in studies of soil genesis and history of landscape development. Some of the principles of recognizing and ranking soil-stratigraphic units are considered especially in the context of Butler's (1959) K cycle theory.Soil- (and rock-) stratigraphic units are recognized in vertical sections by interpretation of the form of depth functions of morphological features or analytical data, or the presence of characteristic soil features, in terms of hypotheses of soil formation and of sediment transport, deposition and diagenesis. Confirmation, and sometimes modification of units recognized in this way may depend on laterally extensive studies, applying accepted stratigraphic criteria concerning superposition and relationships of units. The technique for recognition in a vertical section is illustrated by a number of Australian examples.The aim in soil-stratigraphic studies is to recognize and rank soil-stratigraphic units, not individual soil profiles, so, since soils vary laterally, care is needed in selecting type sites and the soil variation within a unit must be recognized. Some of the aspects of recognizing and ranking soil units are illustrated by studies from a number of situations involving different sequences of soils for each of which different criteria are used. At present there is no sound basis for correlation between these different sequences by comparative morphological or analytical data, so correlation depends on field data and/or isotopic dating. Within each sequence, however, and even between some sequences, there is reason to believe that soil-stratigraphic units can be ranked broadly on their 'degree of development'.

The general economic problem of turning is fairly well appreciated from a qualitative viewpoint; viz., that the reduction in machining cost as the cutting speed is increased will be eventually more than offset by increased tool changing and grinding costs. The problem involves, however, a great number of variables and it must be conceded as axiomatic that the number of variables which can be conveniently handled mathematically is such that a great deal of generality is lost. There is a further risk of loss of generality in attempting to represent the mathematical results in a form suitable for application, preferably graphical. This paper attempts to achieve the initial goal of including at least the fundamental variables in the analysis and representing the results in a reasonably useful form.

For a simple epicyclic train, the controlling element is almost invariably fixed, i.e., prevented from rotating by being connected, in some way, to the frame. Such trains are easy to synthesize because there are a limited number of variations of the three basic elements and, normally, six equations will define all possible velocity ratios. For a compound epicyclic train, the number of equations is considerably increased. A method of synthesizing compound epicyclic trains is developed using the concept of a velocity ratio spectrum. To facilitate the application of this concept, only one train in a compound epicyclic train is regarded as basic; all others are considered as merely serving the purpose of modifying the motion of the controlling element in the basic train.