ALBERT

Notes: Using the static form of a system of equations for seismic waves (de la Cruz & Spanos 1989), we show how various compressibilities can be calculated in a straightforward manner. The results obtained have many points of contact with those found in the literature. In particular, we verify all identities among drained compressibilities given in, e.g., Zimmerman (1991), thus providing an alternative route towards them. The undrained compressibility is described within the context of this work and its relation to the various drained compressibilities (Gassmann 1951) is verified. For greater experimental flexibility, we introduce a one-parameter family of compressibilities which includes the drained and the undrained compressibilities as members. The family of compressibilities is also used to obtain an expression for the pore-pressure build-up coefficient. In this work we also address the problem of macroscopic shearing. Experiments are proposed for the determination of the macroscopic shear modulus, leading to natural expressions for ‘Young's modulus’ and ‘Poisson's ratio’ for the porous medium under drained conditions. We also establish connections with Biot's (1956a) parameters.

Notes: Residues of fluazifop-butyl were determined in strawberries from New Brunswick and Nova Scotia, Canada and North Carolina, U.S.A. using a High Performance Liquid Chromatography (HPLC) system. Strawberries harvested within 28 days of treatment (pre-harvest interval= PHI) had detectable residues of fluazifop, ranging from 0.05 ppmw with a split application of 0.25 kg ha-1 and a 18-day PHI to 3.24 ppmw with a split application of 0.5 kg ha−1 and a 12-day PHI. Fluazifop was not detected in samples treated 287 days or more before harvest (prior growing season) at 0.25–1.65 kg ha−1 (three applications of 0.55 kg ha−1). Fluazifop-butyl did not provide acceptable control (50% with two applications of 0.25 kg ha−1) of Elymus repens (L.) Gould in a commercial planting in New Brunswick. Control of Digitaria sanguinalis (L.) Scop. was better than 90% with two applications of 0.30 kg ha−1 in North Carolina. Fluazifop-butyl did not injure strawberries at any of the rates or sites tested. Résidus et efficacité du fluazifop-butyle en culture de fraises Les résidus du fluazifop-butyle dans des fraises provenant de New Brunswick et Nova Scotia au Canada et de North Carolina aux Etats-Unis ont été déterminés en utilisant un système de chromatographie liquide à haute performance (HPLC). Des fraises récoltées avant 28 jours après le traitement (PHI 28) contenaient des résidus de fluazifop décelables, allant de 0.05 ppmw après un apport fractionné de 0,25 kg ha−1 et PHI 18 à 3,24 ppmw après un apport fractionné de 0,5 kg ha−1 et PHI 12. Nulle trace de fluazifop n'a été décelée dans des échantillons traités au moins 287 jours avant la récolte, c'est-à-dire pendant la saison précédente, aux doses de 0,25 à 1,65 kg ha−1 (trois pulvérisations à 0,55 kg ha−1). Le fluazifop-butyle n'a pas permis une destruction convenable d'Elymus repens (L.) Gould dans une exploitation commerciale au New Brunswick (50% suivant deux pulvérisations à 0,25 kg ha−1). La destruction de Digitaria sanguinalis (L.) Scop. avec deux pulvérisations à 0,30 kg ha−1 en North Carolina dépassait 90%. Le fluazifop-butyle n'a provoqué de dégâts dans les fraises à aucune des doses testées ni à aucune localité. Rückstände und Wirkung von Fluazifop-Butyl in Erdbeeren Erdbeeren von Neu-Braunschweig, Neu-Schott-land (Kanada) und Nord-Karolina (U.S.A.) wurden mittels Hochleistungs-Flüssigkeits-Chromatographie (HPLC) auf Rückstande von Fluazifop-Butyl untersucht. Innert 28 Tagen nach der Behandlung (Intervall vor der Ernte = PHI) geerntete Erdbeeren enthielten messbare Rückstande von Fluazifop; sie betrugen zwischen 0,05 ppmw nach einer Split-Applikation von 0,25 kg ha−1 und einem PHI von 18 Tagen und 3,24 ppmw nach Split-Applikation von 0,5 kg ha−1 und 12 Tagen PHI. Es wurden keine Rückstände in Proben gefunden, die 287 oder mehr Tage vor der Ernte mit 0,5–1,65 kg ha−1 (drei Applikationen von je 0,55 kg ha−1) behandelt worden waren (vor der Wachstumsperiode). Fluazifop-Butyl erzielte keine genügende Kontrolle von Elymus repens (L.) Gould (50% Erfolg nach zwei Behandlungen mit 0,25 kg ha−1) in einer Produktionspflanzung in Neu-Braunschweig. Der Erfolg gegen Digitaria sanguinalis (L.) Scop. war in Nord-Karolina nach zwei Applikationen von 0,30 kg ha−1 höher als 98%. Fluazifop-Butyl schädigte die Erdbeeren an keinem der Standorte und mit keiner Dosierung.

Notes: Abstract This, the second of two papers, represents the application of a least squares approach, discussed in the previous paper, to the generation of an internally consistent thermodynamic dataset involving 60 reactions among 43 phases, in the system K2O–Na2O–CaO–MgO–Al2O3–SiO2–H2O–CO2. We make the assumption that all the thermodynamic data, with the exception of enthalpies of formation of the phases, are well known, and solve for an internally consistent set of enthalpies which reproduces the 60, experimentally determined, phase equilibrium reactions. An important difference between our dataset and that of previous alternatives in the literature is that we are able to determine the uncertainties on, and correlations between, the enthalpies of formation for all phases in the set, and hence are able to apply simple error propagation techniques to determine the uncertainties in any phase equilibrium calculations performed using this dataset. Selection of reactions, for geothermometry and geobarometry, may be more readily made by choosing equilibria with small uncertainties in their thermodynamics. Our data are in reasonably close agreement with the high temperature molten oxide calorimetry results on silicate minerals where available, a fact which lends a degree of confidence to the results.

Notes: Abstract This, the first two papers, sets out the philosophy and methods of determining an internally consistent thermodynamic dataset for minerals using the least squares method. The applicability of the least squares method is discussed, and it is applied to a small set of experimental equilibria in the system Na2O–Al2O3–SiO2–H2O. The importance is stressed of defining not only the enthalpies of formation of minerals, but also the uncertainties and the correlations among them. The system which has been used as an illustration for this paper serves as a visual guide to the method, as it is small enough to represent graphically in two dimensions. In the paper which follows, we extend the method to a system of 60 equations (experimentally determined equilibria) involving 34 unknowns (enthalpies of formation of mineral end-members).

Notes: Abstract New occurrences of crossite and jadeitic pyroxene are described from a thick metabasite unit within the upper levels of the Peripheral Schieferhülle in the Tauern Window, Austria. Unusual textures are preserved which provide evidence for the reactions and mechanisms involved in the breakdown of crossite and jadeitic pyroxene. Zones of albite and chlorite, produced by reaction between crossite and paragonite, have been preserved due to sluggish reaction kinetics during decompression from the blueschist to the greenschist facies. The zonal sequence is interpreted in terms of chemical potential gradients in Na, Mg and Al, which have been established by overstepping the equilibrium boundary. Breakdown textures of jadeite-acmite pyroxene to a symplectite of albite + hematite + actinolite, and of crossite to talc and actinolite are also described.The occurrence of crossite and jadeitic pyroxene at high levels within the Peripheral Schieferhülle implies that even upper levels of the structural sequence have undergone blueschist facies metamorphism with pressures in excess of 8 kbar during the Alpine collisional event.

Notes: Methods of creating digital terrain and landscape models for regional and site specific visualisations are described. A number of alternative approaches are discussed and their relative accuracies are considered. This is followed by a review of the computer graphics procedures which can be used to render such models. Particular attention is directed towards methods for depth cueing, hidden surface removal, shading and texturing. The effects of the atmosphere and methods of producing shadows are also examined. The paper then presents varied applications of such visualisations, including small scale, regional examples and large scale, site specific applications. In conclusion, the role of photogrammetry in the process of visualisation is assessed and possible future developments in this field are identified.

Notes: Abstract. Nitrogen (N) is of enviromental concern if it leaches or is released as nitrous oxide (N2O,). In order to utilize N efficiently in grazed pasture systems, the fluxes of N from various sources need to be quantified. One flux is N mineralization from organic sources. Previous work has examined incubation and chemical extraction of soils as methods to determine N mineralization potential. This paper re-examines new and previously published data on net mineralization, with the aim of examining the relationships between soil thermal units, net N mineralization (measured using acetylene incubations) and dry matter production in pastures. Net N mineralization is expressed as N turnover (net N mineralization as a % of total soil N). Relationships are developed between soil thermal units, dry matter production, and N turnover. These relationships have potential in advising farmers on potential N mineralization from soil organic matter. A second use of such relationships is the modelling of N transformations in pasture systems. Further work should explore the effect of soil moisture on such relationships and examine the relationship between soil thermal units and uptake of N by pasture.

Notes: This paper describes a method of generating pseudovelocity logs using measurements of electrical resistivity. A theoretical relation between electrical resistivity and transit time, which is applicable to a wide range of lithologies, has been developed. The application of this relation using a method which defines lithoresistivity zones as lithological intervals related to the same formation and showing small resistivity variations, has been tested in the Recôncavo sedimentary basin in Bahia, Brazil. A comparison of derived pseudovelocity logs with actual sonic logs for five wells whows the validity of the present approach.

Notes: The effect of annually switching sward management between cutting regimes that simulated rotational grazing and those for forage conservation vs. maintaining a constant management regime was studied by testing for ranking-order changes between six perennial ryegrass varieties.Total dry-matter (DM) yields were found to change in response to an annual switch in management. When under a conservation management and switched in the next year to simulated grazing, all six varieties yielded more in that year than when they were maintained constantly under simulated grazing. Similarly, when under a simulated grazing management and switched in the next year to conservation, all six varieties yielded less than when maintained constantly under a conservation management. These yield differences were largely expressed in spring of the year following the management switch.Differences in the ranking order of varieties were observed between the constant sward management treatments and the alternating managements. However, in these changes in variety ranking, no variety was consistently favoured or disadvartaged by the annual switch in management. Therefore, no clear evidence was produced that an alternating management system had any consistent effect on variety ranking and the observed changes were possibly due to the normal year-to-year variation frequently recorded in variety performance trials.