Effect of a resistive load on the starting performance of a standing wave thermoacoustic engine: A numerical study.

The influence of a resistive load on the starting performance of a standing-wave thermoacoustic engine is investigated numerically. The model used is based upon a low Mach number assumption; it couples the two-dimensional nonlinear flow and heat exchange within the thermoacoustic active cell with one-dimensional linear acoustics in the loaded resonator. For a given engine geometry, prescribed temperatures at the heat exchangers, prescribed mean pressure, and prescribed load, results from a simulation in the time domain include the evolution of the acoustic pressure in the active cell.

Long-term assessment of glucosuria in captive okapi (Okapia johnstoni) after a dietary change.

Glucosuria in okapis (Okapia johnstoni) was first documented in 1980, yet the etiology remains unclear. In August 2006, an attempt to lower glucosuria in captive okapi by diet modification (omitting all fruit and adding unmolassed beet pulp) was started at the Antwerp Zoo. To study the possible relationship between glucosuria and diet, stress, and/or pregnancy, four okapis were monitored over a period of 4.

Prevalence of methicillin-resistant Staphylococcus aureus in mammals of the Royal Zoological Society of Antwerp, Belgium.

Contrary to the numerous reports on methicillin-resistant Staphylococcus aureus (MRSA) in domestic animals, only three articles concerning zoo animals are documented in the literature. A skin infection of an African elephant (Loxodonta africana) calf was most likely acquired from an infected caretaker. Another zoo detected MRSA in the rumen content of a mouflon (Ovis aries), and, in a third facility, it was reported in a fistulous wound at the coronary band of a digit of an Indian rhinoceros (Rhinoceros unicornis).

Low Mach number analysis of idealized thermoacoustic engines with numerical solution.

A model of an idealized thermoacoustic engine is formulated, coupling nonlinear flow and heat exchange in the heat exchangers and stack with a simple linear acoustic model of the resonator and load. Correct coupling results in an asymptotically consistent global model, in the small Mach number approximation. A well-resolved numerical solution is obtained for two-dimensional heat exchangers and stack.

Light and scanning electron microscopy of the cardiac gland region of the stomach of the babirusa (Babyrousa babyrussa--Suidae, Mammalia).

Previous studies have indicated that the gross anatomical structure of the stomach of the babirusa (Babyrousa babyrussa) differs markedly from that of all other pigs. This light and scanning electron microscopic study revealed a previously unknown, microscopic structure characterised by a 'honeycomb' pattern at the luminal surface of the tunica mucosa. The walls of the 'honeycomb' were about 0.

Detection of pathogenic Listeria spp. in zoo animal faeces: use of immunomagnetic separation and a chromogenic isolation medium.

Faecal samples, collected from 200 healthy animals in Antwerp Zoo, were examined for the presence of pathogenic Listeria spp. A two-stage standard isolation (ISO) method was combined with immunomagnetic separation (IMS). ALOA agar, a chromogenic isolation medium, differentiating Listeria spp.