Membrane bioreactor aeration: investigation of the velocity flow pattern.

Results of investigations concerning membrane bioreactor aeration are presented which were carried out at the Institute of Environmental Engineering of RWTH Aachen University (ISA) in cooperation with the Department of Chemical Engineering of the Technische Universität Berlin. In the field of industrial and municipal wastewater treatment the use of membrane bioreactors (MBR) is of increasing interest especially due to the high requirements on effluent quality nowadays. The design of aeration systems is a very important aspect of MBR development because it influences both cost of operation and filtration flux. The ISA has carried out tests concerning the velocity flow pattern in flat sheet membrane modules (developed by the A3 Water Solutions GmbH) to identify the effects of different aeration systems, aeration intensities and module constructions. The Department of Chemical Engineering is currently using the results obtained from the ADV to calibrate a numerical model which simulates two phase water and gas flow within an aerated membrane module. Optical investigations concerning the bubble distribution give a better understanding of the flow conditions in MBR. Developing a numerical tool for membrane module optimization concerning the hydrodynamics is the aim of the investigation of membrane bioreactor aeration.

[Care of persons with aphasia--a review of the literature]. / Pflege von Menschen mit Aphasie--Eine Literaturstudie.

What patients suffering from aphasia experience was examined by Helmbold et al. (1998). The course of the illness was described and divided into six stages. Other models of recovery processes do not take into account the fact that patients who have suffered a stroke are very often confronted with the problem of speech impairment which leads to a delay in recovery. If patients cannot talk to or interact with friends and relatives or professional carers they find it almost impossible to grasp their own clinical symptoms and ultimately to accept them. Nurses working in general hospitals rarely centre their attention on the individual needs of the patients, with the result that there is little or no interaction between patients with aphasia and their carers. This leads to isolation and depression. Interventions have shown that communication is possible even when there is serious speech impairment. In all attempts to encourage communication however the care and attention shown by nurses to aphasic patients is of decisive importance.

Evaluation of vitamin K3 feed additive for prevention of sweet clover disease.

Sweet clover poisoning in cattle is caused by an anticoagulant (dicumarol) that is formed in moldy sweet clover hay. Previous experiments with vitamin K3 and vitamin K1 in therapy trials indicated that vitamin K1 was effective in reducing prothrombin times but vitamin K3 was not. As a possible alternative in the use of toxic sweet clover hays, vitamin K3 was evaluated to see if it would prevent hemorrhagic crises when fed to cattle consuming toxic sweet clover hay. Vitamin K3 levels of 0, 0.45, 4.5, 11, and 45 mg/kg body weight/day were fed to 173-235-kg steers consuming toxic (40-50 ppm dicumarol) sweet clover. The 45-mg K3/kg/day supplement was not palatable and had to be discontinued. The 0.45, 4.5, and 11-mg K3/kg/day supplements did not significantly reduce the prothrombin times as compared to the 0-mg K3/kg/day group.