Factors controlling the origin of gas in Australian Bowen Basin coals

Open system pyrolysis (heating rate 10 degrees C/min) of coal maturity (vitrinite reflectance, VR) sequence (0.5%, 0.8% and 1.4% VR) demonstrates that there are two stages of thermogenic methane generation from Bowen Basin coals. The first and major stage shows a steady increase in methane generation maximising at 570 degrees C, corresponding to a VR of 2-2.5%. This is followed by a less intense methane generation which has not as yet maximised by 800 degrees C (equivalent to VR of 5%). Heavier (C2+) hydrocarbons are generated up to 570 degrees C after which only the C-1 (CH4, CO and CO2) gases are produced. The main phase of heavy hydrocarbon generation occurs between 420 and 510 degrees C. Over this temperature range,methane generation accounts for only a minor component, whereas the wet gases (C-2-C-5) are either in equal abundance or are more abundant by a factor of two than the liquid hydrocarbons. The yields of non-hydrocarbon gases CO2 and CO are greater then methane during the early stages of gas generation from an immature coal, subordinate to methane during the main phase of methane generation after which they are again dominant. Compositional data for desorbed and produced coal seam gases from the Bowen show that CO2 and wet gases are a minor component. This discrepancy between the proportion of wet gas components produced during open system pyrolysis and that observed in naturally matured coals may be the result of preferential migration of wet gas components, by dilution of methane generated during secondary cracking of bitumen, or kinetic effects associated with different activations for production of individual hydrocarbon gases. Extrapolation of results of artificial pyrolysis of the main organic components in coal to geological significant heating rates suggests that isotopically light methane to delta(13)C of -50 parts per thousand can be generated. Carbon isotope depletions in C-13 are further enhanced, however, as a result of trapping of gases over selected rank levels (instantaneous generation) which is a probable explanation for the range of delta(13)C values we have recorded in methane desorbed from Bowen Basin coals (-51 +/- 9 parts per thousand). Pervasive carbonate-rich veins in Bowen Basin coals are the product of magmatism-related hydrothermal activity. Furthermore, the pyrolysis results suggest an additional organic carbon source front CO2 released at any stage during the maturation history could mix in varying proportions with CO2 from the other sources. This interpretation is supported by C and O isotopic ratios, of carbonates that indicate mixing between magmatic and meteoric fluids. Also, the steep slope of the C and O isotope correlation trend suggests that the carbonates were deposited over a very narrow temperature interval basin-wide, or at relatively high temperatures (i.e., greater than 150 degrees C) where mineral-fluid oxygen isotope fractionations are small. These temperatures are high enough for catagenic production of methane and higher hydrocarbons from the coal and coal-derived bitumen. The results suggests that a combination of thermogenic generation of methane and thermodynamic processes associated with CH4/CO2 equilibria are the two most important factors that control the primary isotope and molecular composition of coal seam gases in the Bowen Basin. Biological process are regionally subordinate but may be locally significant. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

In vitro human epidermal and polyethylene membrane penetration and retention of the sunscreen benzophenone-3 from a range of solvents

Purpose. To study epidermal and polyethylene membrane penetration and retention of the sunscreen benzophenone-3 (BP) from a range of single solvent vehicles and evaluate solvent effects on permeability parameters. Methods. The solubility of BP was measured in a number of solvents. Penetration of BP across human epidermis and high density polyethylene (HDPE) membranes was studied from 50% saturated solutions in each solvent. Results. Maximal BP fluxes from the solvents across the two membranes varied widely. Highest fluxes were observed from 90% ethanol (EtOH) for epidermis and from isopropyl myristate (IPM) and C12-15 benzoate alcohols (C12-15 BA) for HDPE membrane. Both the flux and estimated permeability coefficient and skin-vehicle partitioning of BP appeared to be related to the vehicle solubility parameter (delta(v)). The major effects of solvents on BP flux appear to be via changes in BP diffusivity through the membranes. Conclusions. Minimal penetration of sunscreens such as BP is best achieved by choosing vehicles with a delta(v) substantially different to the solubility parameter of the membrane.

Experimental study of phase equilibria in the system PbO-ZnO-SiO2

An experimental study on the ternary system PbO-ZnO-SiO2, in air by high-temperature equilibration and quenching techniques followed by electron probe X-ray microanalysis was carried out as part of the wider research program on the six-component system PbO-ZnO-SiO2-CaO-FeO-Fe2O3, which combines experimental and thermodynamic computer modeling techniques to characterize zinc and lead industrial slags. Liquidus and solidus data were reported for all primary phase fields in the system PbO-ZnO-SiO2 in the temperature range 640 degrees C to 1400 degrees C (913 to 1673 K).

Fluctuations in heroin purity and the incidence of fatal heroin overdose

In order to determine the role played by heroin purity in fatal heroin overdoses, time series analyses were conducted on the purity of street heroin seizures in south western Sydney and overdose fatalities in that region. A total of 322 heroin samples were analysed in fortnightly periods between February 1993 to January 1995. A total of 61 overdose deaths occurred in the region in the study period. Cross correlation plots revealed a significant correlation of 0.57 at time lag zero between mean purity of heroin samples per fortnight and number of overdose fatalities. Similarly, there was a significant correlation of 0.50 at time lag zero between the highest heroin purity per fortnight and number of overdose fatalities. The correlation between range of heroin purity and number of deaths per fortnight was 0.40. A simultaneous multiple regression on scores adjusted for first order correlation indicated both the mean level of heroin purity and the range of heroin purity were independent predictors of the number of deaths per fortnight. The results indicate that the occurrence of overdose fatalities was moderately associated with both the average heroin purity and the range of heroin purity over the study period. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

Isolation and characterization of a Clostridium sp with cinnamoyl esterase activity and unusual cell envelope ultrastructure

Microorganisms that hydrolyse the ester linkages between phenolic acids and polysaccharides in plant cell walls are potential sources of enzymes for the degradation of lignocellulosic waste. An anaerobic, mesophilic, spore-forming, xylanolytic bacterium with high hydroxy cinnamic acid esterase activity was isolated from the gut of the grass-eating termite Tumilitermes pastinator. The bacterium was motile and rod-shaped, stained gram-positive, had an eight-layered cell envelope, and.formed endospores. Phylogenetic analysis based on 16S rRNA indicated that the bacterium is closely related to Clostridium xylanolyticum and is grouped with polysaccharolytic strains of clostridia. A wide range of carbohydrates were fermented, and growth was stimulated by either xylan or cellobiose as substrates. The bacterium hydrolysed and then hydrogenated the hydroxy cinnamic acids (ferulic and p-coumaric acids), which are esterified to arabinoxylan in plant cell walls. Three cytoplasmic enzymes with hydroxy cinnamic acid esterase activity were identified using non-denaturing gel electrophoresis. This bacterium possesses an unusual multilayered cell envelope in which both leaflets of the cytoplasmic membrane, the peptidoglycan layer and the S layer are clearly discernible. The fate of all these components was easily followed throughout the endospore formation process. The peptidoglycan component persisted during the entire morphogenesis. It was seen to enter the septum and to pass with the engulfing membranes to surround the prespore. It eventually expanded to form the cortex, verification for the peptidoglycan origin of the cortex. Sporogenic vesicles, which are derived from the cell wall peptidoglycan, were associated with the engulfment process. Spore coat fragments appeared early, in stage II, though spore coat formation was not complete until after cortex formation.

New integrable model of correlated electrons with off-diagonal long-range order from so(5) symmetry

We present a new integrable model for correlated electrons which is based on so(5) symmetry. By using an eta-pairing realization we construct eigenstates of the Hamiltonian with off-diagonal long-range order. It is also shown that these states lie in the ground state sector. We exactly solve the model on a one-dimensional lattice by the Bethe ansatz.

Extraordinary and extensive karyotypic variation: A 48-fold range in chromosome number in the gall-inducing scale insect Apiomorpha (Hemiptera : Coccoidea : Eriococcidae)

Chromosome number reflects strong constraints on karyotype evolution, unescaped by the majority of animal taxa. Although there is commonly chromosomal polymorphism among closely related taxa, very large differences in chromosome number are rare. This study reports one of the most extensive chromosomal ranges yet reported for an animal genus. Apiomorpha Rubsaamen (Hemiptera: Coccoidea: Eriococcidae), an endemic Australian gall-inducing scale insect genus, exhibits an extraordinary 48-fold variation in chromosome number with diploid numbers ranging from 4 to about 192. Diploid complements of all other eriococcids examined to date range only from 6 to 28. Closely related species of Apiomorpha usually have very different karyotypes, to the extent that the variation within some species- groups is as great as that across the entire genus. There is extensive chromosomal variation among populations within 17 of the morphologically defined species of Apiomorpha indicating the existence of cryptic species-complexes. The extent and pattern of karyotypic variation suggests rapid chromosomal evolution via fissions and (or) fusions. It is hypothesized that chromosomal rearrangements in Apiomorpha species may be associated with these insects' tracking the radiation of their speciose host genus, Eucalyptus.

Long range forecasts of the numbers of Helicoverpa punctigera and H-armigera (Lepidoptera : Noctuidae) in Australia using the Southern Oscillation Index and the Sea Surface Temperature

The use of long-term forecasts of pest pressure is central to better pest management. We relate the Southern Oscillation Index (SOI) and the Sea Surface Temperature (SST) to long-term light-trap catches of the two key moth pests of Australian agriculture, Helicoverpa punctigera (Wallengren) and H. armigera (Hubner), at Narrabri, New South Wales over 11 years, and for H. punctigera only at Turretfield, South Australia over 22 years. At Narrabri, the size of the first spring generation of both species was significantly correlated with the SOI in certain months, sometimes up to 15 months before the date of trapping. Differences in the SOI and SST between significant months were used to build composite variables in multiple regressions which gave fitted values of the trap catches to less than 25% of the observed values. The regressions suggested that useful forecasts of both species could be made 6-15 months ahead. The influence of the two weather variables on trap catches of H. punctigera at Turretfield were not as strong as at Narrabri, probably because the SOI was not as strongly related to rainfall in southern Australia as it is in eastern Australia. The best fits were again given by multiple regressions with SOI plus SST variables, to within 40% of the observed values. The reliability of both variables as predictors of moth numbers may be limited by the lack of stability in the SOI-rainfall correlation over the historical record. As no other data set is available to test the regressions, they can only be tested by future use. The use of long-term forecasts in pest management is discussed, and preliminary analyses of other long sets of insect numbers suggest that the Southern Oscillation Index may be a useful predictor of insect numbers in other parts of the world.

Experimental examination of solute transport by surface runoff from low-angle slopes

The removal of chemicals in solution, by overland flow from agricultural land has the potential to be a significant source of chemical loss from zero-till and surface mulched farming systems. The objective of this study was to determine the magnitude of solute loss by surface runoff from agricultural systems. Previous experiments have enhanced the understanding of the exchange process, but the initial soil conditions together with the tracer application method in these experiments have meant that in some cases the results have limited applicability to field situations. In this study, two different sets of experiments were carried out to determine the magnitude of solute loss by surface runoff. These experiments entailed the surface application of bromide to (1) field scale plots 18 m long by 2 m wide and (2) repacked soil cores 236 mm in diameter; followed by the application of simulated rainfall in both cases. The most substantial finding of the field experiments was that the quantities of solute in surface runoff varied greatly with soil type and structure (0.07-14.9% of the applied bromide). Also, on some soils, large quantities of tracer were measured in the surface runoff even after several hours of infiltration. The experiments on soil cores showed that soil structure plays an important role in the quantity of chemical that may be transported in the surface runoff. These field results showed that, in certain systems, solute movement by overland flow is an important transport mechanism, which should be considered when budgeting for chemical loss. (C) 2000 Elsevier Science B.V. All rights reserved.

Early diagnosis of lymphedema in postsurgery breast cancer patients

Lymphedema is an accumulation of lymph fluid in the limb resulting from an insufficiency of the lymphatic system. It is commonly associated with surgical or radiotherapy treatment for breast cancer. As with many progressively debilitating disorders, the effectiveness of treatment is significantly improved by earlier intervention. Multiple frequency bioelectrical impedance analysis (MFBIA) previously was shown to provide accurate relative measures of lymphedema in the upper limb in patients after treatment for breast cancer, This presentation reports progress to date on a three-year prospective study to evaluate the efficacy of MFBIA to predict the early onset of lymphedema in breast cancer patients following treatment. Bioelectrical impedance measurements of each upper limb were recorded in a group of healthy control subjects (n = 50) to determine the ratio of extracellular limb-fluid volumes. From this population, the expected normal range of asymmetry (99.7% confidence) between the limbs was determined, Patients undergoing surgery to treat breast cancer were recruited into the study, and MFBIA measurements were recorded presurgery, at one month and three months after surgery, and then at two-month intervals for up to 24 months postsurgery, When patients had an MFBIA measure outside the 99.7% range of the control group, they were referred to their physician for clinical assessment. Results to date: Over 100 patients were recruited into the study over the past two years; at present, 19 have developed lymphedema and, of these, 12 are receiving treatment. In each of these 19 cases, MFBIA predicted the onset of the condition up to four months before it could be clinically diagnosed. The false-negative rate currently is zero, The study will continue to monitor patients over the remaining year to accurately ascertain estimates of specificity and sensitivity of the procedure.

Indicators used to measure the innovation process: defects and possible remedies

Some diverse indicators used to measure the innovation process are considered, They include those with art aggregate, and often national, focus, and rely on data from scientific publications, patents and R&D expenditures, etc. Others have a firm-level perspective, relying primarily on surveys or case studies. Also included are indicators derived from specialized databases, or consensual agreements reached through foresight exercises. There is an obvious need for greater integration of the various approaches to capture move effectively the richness of available data and better reflect the reality of innovation. The focus for such integration could be in the area of technology strategy, which integrates the diverse scientific, technological, and innovation activities of firms within their operating environments; improved capacity to measure it has implications for policy-makers, managers and researchers.

Simultaneous steady state and dynamic design of process systems using structural indicators

The simultaneous design of the steady-state and dynamic performance of a process has the ability to satisfy much more demanding dynamic performance criteria than the design of dynamics only by the connection of a control system. A method for designing process dynamics based on the use of a linearised systems' eigenvalues has been developed. The eigenvalues are associated with system states using the unit perturbation spectral resolution (UPSR), characterising the dynamics of each state. The design method uses a homotopy approach to determine a final design which satisfies both steady-state and dynamic performance criteria. A highly interacting single stage forced circulation evaporator system, including control loops, was designed by this method with the goal of reducing the time taken for the liquid composition to reach steady-state. Initially the system was successfully redesigned to speed up the eigenvalue associated with the liquid composition state, but this did not result in an improved startup performance. Further analysis showed that the integral action of the composition controller was the source of the limiting eigenvalue. Design changes made to speed up this eigenvalue did result in an improved startup performance. The proposed approach provides a structured way to address the design-control interface, giving significant insight into the dynamic behaviour of the system such that a systematic design or redesign of an existing system can be undertaken with confidence.

The evolution and star formation of dwarf galaxies in the Fornax Cluster

We present the results of a spectroscopic survey of 675 bright (16.5 < b(J) < 18) galaxies in a 6 degrees field centred on the Fornax cluster with the FLAIR-II spectrograph on the UK Schmidt Telescope. Three galaxy samples were observed: compact galaxies to search for new blue compact dwarfs, candidate M 32-like compact dwarf ellipticals, and a subset of the brightest known cluster members in order to study the cluster dynamics. We measured redshifts for 516 galaxies, of which 108 were members of the Fornax Cluster. Defining dwarf galaxies to be those with b(J) greater than or equal to 15 (M-B greater than or equal to - 16.5), there are a total of 62 dwarf cluster galaxies in our sample. Nine of these are new cluster members previously misidentified as background galaxies. The cluster dynamics show that the dwarf galaxies are still falling into the cluster whereas the giants are virialized. We classified the observed galaxies as late-type if we detected H alpha emission at an equivalent width greater than 1 Angstrom. The spectra were obtained through fixed apertures, so they reflect activity in the galaxy cores, but this does not significantly bias the classifications of the compact dwarfs in our sample. The new classifications reveal a higher rate of star formation among the dwarf galaxies than suggested by morphological classification: 35 per cent have significant H alpha emission indicative of star formations but only 19 per cent were morphologically classified as late-types. The star-forming dwarf galaxies span the full range of physical sizes and we find no evidence in our data for a distinct class of star-forming blue compact dwarf (BCD) galaxy. The distribution of scale sizes is consistent with evolutionary processes which transform late-type dwarfs to early-type dwarfs. The fraction of dwarfs with active star formation drops rapidly towards the cluster centre: this is the usual density-morphology relation confirmed here for dwarf galaxies. The star-forming dwarfs are concentrated in the outer regions of the cluster, the most extreme in an infalling subcluster. We estimate gas depletion time-scales for five dwarfs with detected Hi emission: these are long (of order 10(10) yr), indicating that an active gas removal process must be involved if they are transformed into gas-poor dwarfs as they fall further into the cluster. Finally, in agreement with our previous results, we find no compact dwarf elliptical (M 32-like) galaxies in the Fornax Cluster.

Finite element modelling of rock alteration and metamorphic process in hydrothermal systems

We use the finite element method to simulate the rock alteration and metamorphic process in hydrothermal systems. In particular, we consider the fluid-rock interaction problems in pore-fluid saturated porous rocks. Since the fluid rock interaction takes place at the contact interface between the pore-fluid and solid minerals, it is governed by the chemical reaction which usually takes place very slowly at this contact interface, from the geochemical point of view. Due to the relative slowness of the rate of the chemical reaction to the velocity of the pore-fluid flow in the hydrothermal system to be considered, there exists a retardation zone, in which the conventional static theory in geochemistry does not hold true. Since this issue is often overlooked by some purely numerical modellers, it is emphasized in this paper. The related results from a typical rock alteration and metamorphic problem in a hydrothermal system have shown not only the detailed rock alteration and metamorphic process, but also the size of the retardation zone in the hydrothermal system. Copyright (C) 2001 John Wiley & Sons, Ltd.

Analytical solution to the zero-inertia problem for surge flow phenomena in nonprismatic channels

Surge flow phenomena. e.g.. as a consequence of a dam failure or a flash flood, represent free boundary problems. ne extending computational domain together with the discontinuities involved renders their numerical solution a cumbersome procedure. This contribution proposes an analytical solution to the problem, It is based on the slightly modified zero-inertia (ZI) differential equations for nonprismatic channels and uses exclusively physical parameters. Employing the concept of a momentum-representative cross section of the moving water body together with a specific relationship for describing the cross sectional geometry leads, after considerable mathematical calculus. to the analytical solution. The hydrodynamic analytical model is free of numerical troubles, easy to run, computationally efficient. and fully satisfies the law of volume conservation. In a first test series, the hydrodynamic analytical ZI model compares very favorably with a full hydrodynamic numerical model in respect to published results of surge flow simulations in different types of prismatic channels. In order to extend these considerations to natural rivers, the accuracy of the analytical model in describing an irregular cross section is investigated and tested successfully. A sensitivity and error analysis reveals the important impact of the hydraulic radius on the velocity of the surge, and this underlines the importance of an adequate description of the topography, The new approach is finally applied to simulate a surge propagating down the irregularly shaped Isar Valley in the Bavarian Alps after a hypothetical dam failure. The straightforward and fully stable computation of the flood hydrograph along the Isar Valley clearly reflects the impact of the strongly varying topographic characteristics on the How phenomenon. Apart from treating surge flow phenomena as a whole, the analytical solution also offers a rigorous alternative to both (a) the approximate Whitham solution, for generating initial values, and (b) the rough volume balance techniques used to model the wave tip in numerical surge flow computations.