The Basic Effects of Recycling on Pulp Properties

Using standard laboratory procedures it was found that different pulp types showed very different recycling effects. Mechanical pulp fibres became flatter and more flexible giving a denser, stronger sheet. Beaten chemical pulp fibres “hornified”, resulting in a bulkier, weaker sheet. Unbeaten chemical pulp fibres were initially curly; recycling removed the curl. A mechanical/chemical pulp blend revealed that these effects occur at different rates. In no case was there evidence of fibre strength loss, or of fibre embrittlement. In these laboratory experiments, fines loss during sheetmaking affected the magnitude of the sheet properties, but not the trends.

Continuous postoperative monitoring of cortical blood flow and intracranial pressure

A new technique to continuously monitor cortical blood flow and intracranial pressure in postoperative patients is described. A thermal diffusion flow probe with a pressure port is left in contact with the cortex at craniotomy. Postoperative intracranial pressure--cortical blood flow can be monitored and acute changes or trends are readily detected. The thermal flow probe has been previously compared with radioactive xenon (133Xe) clearance and hydrogen clearance methods of measuring cortical blood flow in animals. The technique gives a real-time quantitative indication of flow. Changes in cortical blood flow can be observed within a few seconds and the effects of treatment can be readily observed. Changes in flow due to vasospasm have been demonstrated in subarachnoid hemorrhage. It is anticipated that information learned from this method will aid in the management of patients with head trauma, tumors, and subarachnoid hemorrhage.