Apparatus for calibration of a uroflowmeter.
A device has been constructed in order to obtain a flow analogous with the flow during micturition. Sources of error with instruments used in connection with micturition analysis can be determined by using this apparatus.
A simple uroflowmeter tester.
A simple device for testing urine flowmeters is described. It is made from readily available components and is portable, easy to use, and requires no special care in setting up. The flow rate is accurate to within 0.5 ml/s. Nursing staff are now able to do regular calibration checks on the urine flowmeters and some flowmeter deficiencies have been exposed. Using the tester, examples of artefactual peak flow rates have been recorded.
Coherent structures in the magnetotail triggered by counterstreaming electron beams
We describe wave observations carried out on board Galileo during the crossing of a flux rope in the Earth magnetotail. Waveform observations give evidence for transient electrostatic structures. Numerical simulations of the evolution of counterstreaming electron beams with a core of hotter ions have been performed with parameters consistent with Galileo observations during the flux rope crossing. A strongly unstable mode, with a zero real part of the frequency is found to develop and to lead to the generation of coherent electrostatic structures with velocities between ±υt, the electron thermal velocity. The characteristics of the simulated structures are shown to be similar to those observed in the magnetotail.