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Measured were the cutting forces, the power requirements and the surface roughness during the machining of pieces of beech (Fagus silvatica) and spruce (Picea excelsa). The machining process was carried out on a shaper with speci®c devices. The concerned variables were: cutting depth, feed rate and cutting speed. The mean chip thickness and cutting width were constant. The machining process was done in two different ways: conventional and climb cutting; thus it was possible to compare both working directions with the same machining parameters and watch their in¯uence on the cutting forces, the power consumption and the surface roughness. The most important variables on the cutting forces are depth of cut, wood density and feed direction. With regard to power consumption, it was detected that the most important variables were cutting speed, feed direction, depth of cut and wood density. It was further demonstrated that the measured and calculated power have a very good correlation, and that the cutting forces can be determined by the calculated power. Thus, if cutting power is measured for a speci®c condition of wood and machine, the cutting forces can be estimated. The surface roughness was very homogeneous in all the tests. The better machining process was obtained when applying conventional cutting. Then the cutting forces, the power requirements and the roughness standard deviation reach smaller values. Qualifikation der spanenden Bearbeitung von Hartholz am Beispiel von Fagus silvatica L. und Picea excelsa L.: Schnittkra Èfte, Leistungsbedarf und Oberfla Èchengu Ète Die Messungen der Schnittkra Èfte, des Leistungsbedarfs und der Ober¯a Èchenbeschaffenheit wurden durchgefu Èhrt an Buchenholz (Fagus silvatica) und Fichtenholz (Picea excelsa). Der Bearbeitungsprozess erfolgte auf einer speziellen Holzhobelmaschine. Die relevanten Variabeln waren: die Schnitttiefe, der Vorschub und die Schnittgeschwindigkeit. Die mittlere Spansta Èrke und die Schnittbreite waren konstant. Die Bearbeitung wurde auf zwei verschiedene Arten durchgefu Èhrt: im Gleichlauf und im Gegenlauf, somit war es mo Èglich, beide Bearbeitungsrichtungen unter Beibehaltung der Parameter zu vergleichen und ihren Ein¯uss auf die Schnittkra Èfte, den Leistungsbedarf und die Ober¯a Èchenrauhigkeit zu pru Èfen. Die wichtigsten Ein¯uûvariabeln bezu Èglich der Schnittkra Èfte waren die Schnitttiefe, die Materialdichte und die Vorschubrichtung. Den Leistungsbedarf betreffend kamen wir zu dem Ergebnis, daû sowohl die Vorschubrichtung, die Materialdichte als auch die Schnittkra Èfte, -geschwindigkeit und -tiefe die Hauptein¯uûfaktoren waren. Es konnte gezeigt werden, daû die gemessene und berechnete Leistung gut korreliert sind, und daû die Schnittkra Èfte mittels der berechneten Leistung bestimmbar sind. Es ist daher mo Èglich, durch Messen des Leistungsbedarfs einer Bearbeitung einer bestimmten Holzart auf einer de®nier-ten Maschine die Schnittkra Èfte abzuscha Ètzen. Die Obera Èchengu Ète war gleichbleibend in allen durchgefu Èhrten Versuchen. Die besten...

A new method for determining the glomerular filtration rate was analysed prospectively. The method uses an x ray fluorescence technique to measure disappearance from the plasma of injected non-ionic iodinated contrast media. Eighty seven patients were studied. Fifty four had an intravenous dose of 100 ml iohexol (Omnipaque) and 33 had 50 ml iohexol. Clearances of chromium-51 labelled edetic acid ("Cr-EDTA) were measured simultaneously. In the patients given 100 ml iohexol there was excellent correlation with 5"Cr-EDTA clearance (r=0-90). The correlation using 50 ml iohexol was also good (r=0-85). Correlation between creatinine clearance and clearance of 5Cr-EDTA in 33 patients was less satisfactory (r=0'69). There were no adverse reactions to the contrast media. The equipment used for measuring contrast clearance was robust and simple to operate. Freezing plasma samples in 10 studies and re-examining them weekly for six weeks showed no significant variation in results; hence reproducibility was good.This new and accurate method for determining the glomerular filtration rate merits further study and might find a useful place in routine clinical practice. IntroductionDetermination of the glomerular filtration rate to measure renal function is often required in urological, nephrological, and general medical practice. Currently available methods include inulin clearance, radionuclide studies using chromium-51 labelled edetic acid ("Cr-EDTA) or technetium-99m labelled diethylene triamine penta-acetic acid ('Tc-DTPA), and creatinine clearance. Because of the complexities ofthe first two methods clinicians often settle for creatinine clearance or even simple plasma creatinine and urea concentrations as less accurate but more convenient measures of renal function in everyday practice. We present our evaluation of a new method for determining the glomerular filtration rate. This is based on the use ofcompact, purpose designed equipment currently known as the ELX 84 (Elementanalys AB, Sweden), which measures the disappearance from plasma of injected, non-ionic iodinated contrast media by an x ray fluorescence technique.

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Morphological changes in immiscible polymer blends have been studied in shear flow using an original method based on quenching following deformation of molten samples Relaxation effects wete expected to be negligible during cooling and, hence, the real shear-induced blend microstructure could be analyzed The method has been successfully applied to follow morphological changes of immiscible blends composed of polystyrene and relatively high amounts of high-density polyethylene during creep experiments. The final steady-state morphology appeared to be intimately related to the applied shear stress and total deformation. Coalescence as well as large deformation and orientation of the dispersed phase panicles have been observed depending on the flow conditions The variations with time of the blend rheological properties and morphological observations are in qualitative agreement.