Thermodynamics of airburn of carbon anodes in aluminium reduction cells

Hall-Heroult process

Microwave heating of flowing slurry

Mathematical models are constructed to investigate the use of microwaves to dissolve chemical crystals in a flowing solvent. The slurry is considered to be a Newtonian fluid in which the solvent is heated by microwaves. The solute crystals dissolve at a rate which depends strongly on temperature, and the dissolution has a profound effect on the viscosity of the slurry. Special consideration is given to crystal size and heating effects close to the walls containing the slurry. A simplified version of the mathematical model is solved numerically, and the results lead to suggestions for improved design of the process. We also investigate the implications of non-Newtonian fluid models. The overall outcome of the work is a better understanding of the heat and mass transfer of the slurry, as well as recommendations on crystal size and design of the process

Slag ladle insulation

Slag from Pasminco's lead-zinc smelters, which is rich in zinc, is transferred in thirteen tonne capacity ladles from the blast furnace to the slag fuming furnace. The cycle time is about three hours. The Study Group was asked to examine whether heat could be conserved by some insulation strategy, without at any stage overheating the steel of the ladle

Multispectral scanner optical system

An optical system for use in a multispectral scanner of the type used in video imaging devices is disclosed. Electromagnetic radiation reflected by a rotating scan mirror is focused by a concave primary telescope mirror and collimated by a second concave mirror. The collimated beam is split by a dichroic filter which transmits radiant energy in the infrared spectrum and reflects visible and near infrared energy. The long wavelength beam is filtered and focused on an infrared detector positioned in a cryogenic environment. The short wavelength beam is dispersed by a pair of prisms, then projected on an array of detectors also mounted in a cryogenic environment and oriented at an angle relative to the optical path of the dispersed short wavelength beam

Radicals of 0-regular algebras

We consider a generalisation of the Kurosh--Amitsur radical theory for rings (and more generally multi-operator groups) which applies to 0-regular varieties in which all operations preserve 0. We obtain results for subvarieties, quasivarieties and element-wise equationally defined classes. A number of examples of radical and semisimple classes in particular varieties are given, including hoops, loops and similar structures. In the first section, we introduce 0-normal varieties (0-regular varieties in which all operations preserve 0), and show that a key isomorphism theorem holds in a 0-normal variety if it is subtractive, a property more general than congruence permutability. We then define our notion of a radical class in the second section. A number of basic results and characterisations of radical and semisimple classes are then obtained, largely based on the more general categorical framework of L. M\'arki, R. Mlitz and R. Wiegandt as in [13]. We consider the subtractive case separately. In the third section, we obtain results concerning subvarieties and quasivarieties based on the results of the previous section, and also generalise to subtractive varieties some results for multi-operator group radicals defined by simple equational rules. Several examples of radical and semisimple classes are given for a range of fairly natural 0-normal varieties of algebras, most of which are subtractive

Escherichia coli O157:H7 in Malta for the first time

The emergence of E coli O157:H7 in Malta is a sign of the times. It represents one of the newly emerging infections associated with food. The first two documented cases of E coli 0157:H7 infection in Malta occurred in July and August, 1996. Food types classically incriminated were surveyed by the Department of Public Health. Epidemiological investigation aimed to trace the environmental sources of infection.• Microbiology was performed jointly by diagnostic and public health laboratories. Facts about infection and control of the disease are highlighted with a view to alerting local practitioners to the condition.peer-reviewe

Presence and Function of Tetrodotoxin in Terrestrial Vertebrates and Invertebrates

Tetrodotoxin (TTX) is a potent neurotoxin that acts by blocking the pore region of voltage-gated sodium channels in nerve and muscle tissue. This causes paralysis, and often death due to asphyxiation. Interestingly, TTX is found in an array of organisms ranging from bacterial species to vertebrates. Further, TTX is found in both aquatic and terrestrial environments. This range of taxa and environments has led to three common lines of study for ecological research on this toxin: production, predation, and identification of novel TTX bearing taxa. I began my research by also refining a Competitive Inhibition Enzymatic Immunoassay technique for fast, easy, and inexpensive quantification of TTX. I then focused on the three previously mentioned areas of research. Female newts (Taricha granulosa) are known to endow their eggs with TTX in order to protect them from predation. I looked at whether females allocated TTX to their eggs evenly over three years in captivity and compared those levels to TTX levels in eggs directly after capture. I found that eggs had lower levels of TTX following initial capture, but those levels did not change over the next three years. This provides evidence that TTX is endogenously produced in this species. Because of the high levels of TTX in newts, there are few known predators. I observed river otters feeding on newts in a high elevation lake in Oregon. I found that these newts have very low levels of TTX, and that in general high elevation populations in Oregon have low levels of TTX relative to low elevation populations. Finally, I documented TTX in two species of terrestrial flatworm (Bipalium adventitium and Bipalium kewense). Tetrodotoxin has never before been identified in a terrestrial invertebrate species. Further, I found evidence that suggests that TTX is used for both defense and prey capture in these worms. These studies add to our understanding of the evolution of TTX and how it influences interactions between organisms and their biotic and abiotic environments