STUDIES ON BARLEY AND MALT WITH THE RAPID VISCOANALYSER: [III] THE PREDICTION OF MALTING POTENTIAL FROM VISCOGRAMS

Examination of the relationships between extract and viscogram data of malts suggested the measurement of Time to Peak as a cultivar-independent measure of quality potential. This was tested against a large number of samples from the routine assessment programme. Both barleys and malts were examined. Some comparisons with the Falling Number Apparatus are reported. Prediction of malting potential from the differences between viscograms of barleys with and without added enzyme was also assessed. No measurement from the viscogram of barley was sufficiently accurate for predicting malting potential of a population of crossbreds from a breeding programme.     

Dissolution of various sources of gypsum in aqueous solutions and in soil

The dissolution of six sources of gypsum in water and 0.01 M CaCl₂ was examined in the presence and absence of soil. The gypsum samples included: analytical grade (AR), three sources of flue-gas desulphurisation (FGD) gypsum, phosphogypsum (PG), and mined gypsum (MG). Dissolution in aqueous solutions was monitored by measuring the concentration of calcium (Ca²⁺) and sulphate (SO) ions. In soils which adsorb small amounts of SO^?2₄, dissolution was estimated from the increase in the concentration of Ca²⁺ and SO in gypsum-treated soil over the control soil. However, in soils which adsorb significant amounts of SO, measurement of solution SO concentration underestimates the extent of dissolution. Gypsum dissolution was larger in water (15.20 mmol litre^?1) than in 0.01 M CaCl₂ (11.12 mmol litre^?1), and this was attributed to the Ca²⁺ common-ion effect. The rate of dissolution decreased in the order: AR > FGD > PG > MG. Dissolution was 2 to 10 times faster for powdered (< 500 .m) gypsum than for the discs obtained by pelletising. The differences in the rate of dissolution between the gypsum sources and between powder and disc samples were related to both surface area and the presence of CaCO₃, impurity. The rate of dissolution was 3 to 8 times faster in the presence than in the absence of soil. Whereas the dissolution of gypsum in the presence of soil followed first order reaction kinetics, it followed second order kinetics in the absence of soil. This difference in reaction kinetics resulted from the continuous removal of Ca2+ and SO by the soil.     

VOLUME-OF-FLUID CALCULATION OF HEAT OR MASS TRANSFER ACROSS DEFORMING INTERFACES IN TWO-FLUID FLOW

A new volume-of-fluid (VOF)-based numerical method for calculating heat transfer or mass transfer of a species within and between fluids with deforming interfaces is described. The algorithm is tested first against an analytical solution for diffusion from a sphere, and good agreement between theory and calculation is shown. The method is then demonstrated by predicting (a) heat transfer from a rising bubble when the bubble forms a toroidal shape, and (b) mass transfer from a rising drop when the drop phase controls diffusion. The method is shown to be a viable approach for complex interfacial heat/mass transfer.     

Sources and variations of mercury in tuna

While the bulk of human exposure to mercury is through the consumption of marine fish, most of what we know about mercury methylation and bioaccumulation is from studies of freshwaters. We know little of where and how mercury is methylated in the open oceans, and there is currently a debate whether methylmercury concentrations in marine fish have increased along with global anthropogenic mercury emissions. Measurements of mercury concentrations in Yellowfin tuna caught off Hawaii in 1998 show no increase compared to measurements of the same species caught in the same area in 1971. On the basis of the known increase in the global emissions of mercury over the past century and of a simple model of mercury biogeochemistry in the Equatorial and Subtropical Pacific ocean, we calculate that the methylmercury concentration in these surface waters should have increased between 9 and 26% over this 27 years span if methylation occurred in the mixed layer or in the thermocline. Such an increase is statistically inconsistent with the constant mercury concentrations measured in tuna. We conclude tentatively that mercury methylation in the oceans occurs in deep waters or in sediments.     

Optimal movement in the prey strikes of weakly electric fish: a case study of the interplay of body plan and movement capability

Animal behaviour arises through a complex mixture of biomechanical, neuronal, sensory and control constraints. By focusing on a simple, stereotyped movement, the prey capture strike of a weakly electric fish, we show that the trajectory of a strike is one which minimizes effort. Specifically, we model the fish as a rigid ellipsoid moving through a fluid with no viscosity, governed by Kirchhoff's equations. This formulation allows us to exploit methods of discrete mechanics and optimal control to compute idealized fish trajectories that minimize a cost function. We compare these with the measured prey capture strikes of weakly electric fish from a previous study. The fish has certain movement limitations that are not incorporated in the mathematical model, such as not being able to move sideways. Nonetheless, we show quantitatively that the computed least-cost trajectories are remarkably similar to the measured trajectories. Since, in this simplified model, the basic geometry of the idealized fish determines the favourable modes of movement, this suggests a high degree of influence between body shape and movement capability. Simplified minimal models and optimization methods can give significant insight into how body morphology and movement capability are closely attuned in fish locomotion.     

Assessing the sustainability of the UK society using thermodynamic concepts: Part 1

This paper provides a concise overview of the influence of human activity within the UK society on resource consumption and the subsequent effects on the environment. The concept of the Multi Scale Integrated Analysis of Societal Metabolism (MSIASM) is applied in order to elucidate the evolution of the UK economy for the period between 1981 and 2004. Our findings highlight the transition to a service-based economy and the disproportionate increase of energy demand when compared to the overall population increase. Emergy synthesis is applied in order to understand the production and consumption patterns and the environmental support required to sustain human activity within the UK for the year 2004. Generally speaking the UK society greatly benefits from its significant natural resources with 44.3% of the total emergy used coming from home sources and 29.1% from locally renewable sources. Interestingly enough, despite its significant natural resources, the UK economy, seems to be a net emergy importer by 638.5 × 10²¹ seJ. Furthermore, the current economic activity is believed to have a significant impact in the environment despite the relatively low environmental load ratio of 2.44.     

3D Simulations to investigate initial condition effects on the growth of Rayleigh–Taylor mixing

The effect of initial conditions on the growth rate of turbulent Rayleigh–Taylor (RT) mixing has been studied using carefully formulated numerical simulations. An implicit large-eddy simulation (ILES) that uses a finite-volume technique was employed to solve the three-dimensional incompressible Euler equations with numerical dissipation. The initial conditions were chosen to test the dependence of the RT growth parameters (α_b, α_s) on variations in (a) the spectral bandwidth, (b) the spectral shape, and (c) discrete banded spectra. Our findings support the notion that the overall growth of the RT mixing is strongly dependent on initial conditions. Variation in spectral shapes and bandwidths are found to have a complex effect of the late time development of the RT mixing layer, and raise the question of whether we can design RT transition and turbulence based on our choice of initial conditions. In addition, our results provide a useful database for the initialization and development of closures describing RT transition and turbulence.     

Free-radical involvement in the drying and oxidation of victorian brown coal

The technique of electron spin resonance spectroscopy has been used to study the changes in free-radical nature and content of brown coals as a result of vacuum drying the coal at various temperatures, and exposing the dried coal to either air at room temperature or oxygen at 105 °C. Free-radical concentrations increased during the vacuum-drying process and this is thought to be a result of organic functional group breakdown. Free-radical concentrations in dry coals following air or oxygen exposure have been found to vary with exposure time. The observations can be explained in terms of free-radical involvement in the oxidation process.     

Assessment of nitrogen status of soils for cereal crops: Effects of nitrogen fertiliser on growth,composition and yield of spring barley

The effects of fertiliser N on the growth rate and nitrogen and pigment concentrations of spring barley throughout growth were measured at two locations in north-east Scotland in consecutive years. Inorganic N in soil was also measured as were grain and straw yields at maturity. The results show that plant analysis, as early as 3 or 4 weeks after emergence of barley, was an effective assessment of soil N status.     

Interrelationships between ideologically important thiol,disulphide groups and yield—quality parameters of wheat cultivars (triticu aestivumm L.)

Experiments were conducted with 22 wheat cultivars (Triticum aestivum L.) from the 1976 season which showed the following: grain yields and rheologically important SS/SH ratios were negatively correlated (r= ?0.78). Rdeologically important SS/SH ratios were positively correlated with total flour protein percentages (r=0.61), residue flour protein percentages (r=0.62) and all better dough quality properties. Grain yields and total flour protein percentages were negatively correlated (r=?0.66). However, only the first relationship was statistically valid for 12 recurrent cultivars within the group of 22 which had been yield tested annually from 1971 to 1976, inclusive. Their long-term average yield data (1971–76) were more negatively correlated (r= ?0.87) with the 1976 SS/SH values than their 1976 yield data (r= ?0.78). It is considered that grain yield differences between the cultivars studied were inherently related to differences in their abilities to synthesise more rheologically important thiol groups than disulphide groups during plant growth and grain formation. The SS/SH ratio and grain yield relationship appears to be largely independent of seasonal influences and therefore should be of interest to wheat breeders trying to combine higher yield and better quality objectives in their programmes.