To investigate the validity of the prediction of body water compartments by multi-frequency impedance in Indonesians, 42 adults (19 males and 23 females) were recruited in Jakarta, the capital of Indonesia. Extracellular water (ECW) and total body water (TBW) were measured with dilution techniques and predicted from body impedance at 1 and 100 kHz, respectively, using prediction formulas developed in a Dutch population. Furthermore, body weight, body height and body density were measured and as a measure of body build TBW/height and ECW/height were calculated. Percent ECW of body weight in both males (26 ± 3%) and females (23 ± 2%) was higher compared to the Dutch reference population, and also the body water distribution (ECW/TBW) was higher (0.46 ± 0.04) compared to the reference population. TBW/height and ECW/height appeared to be considerably lower in the Indonesian group compared to the reference group, indicating a more slender body shape. TBW was overestimated by 1.8 ± 2.4 and 2.5 ± 1.3 kg in males and females, respectively. ECW was underestimated in males by 0.1 ± 1.2 kg and slightly overestimated in females (0.1 ± 1.0 kg). After corrections for differences in body build and body water distribution the bias of the predicted TBW was markedly reduced from 2.2 ± 1.9 to 1.3 ± 1.8 kg (males and females combined). For ECW the bias after correction for body water distribution and body build was 0.3 ± 0.6 kg (males and females combined). It is concluded that multi-frequency impedance is suitable for the prediction of body water compartments at the population level but, due to differences in body build and body water distribution, validation in a larger group of Indonesian subjects is needed to avoid systematic prediction errors.

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The kinetics of grain boundary segregation were studied by AES for P in Ni and Ni-ZO%Cr alloys. The relations were determined from grain boundary compositions and mechanical properties. In Ni-;?O%Cr carbon segregation is also observed and precipitation of chromium carbides at the grain boundaries, the interplay of segregation and precipitation was investigated by AES and TEM. EXPERIMENTALNi and Ni-20%Cr alloys with different P-bulk concentrations (Ni; 110 ppm P, 230 ppm P, 540 ppm P and 2-3 ppm S: Ni-20%Cr; 41 ppm P 68 pprn C, 87 ppm P 76 ppm C, 150 ppm P 92 ppm C) were aged for 5 h to 140 days at temperatures between 500 "C and 700 "C. For achieving intergranular fracture, the notched specimens were electrolytically charged with hydrogen in In H,SO, with 2 mA cm-', at room temperature for 48 h (Ni) or 72 h (Ni-20%Cr). Afterwards, the specimens were fractured in a slow strain rate tension machine, which was placed inside the UHV-chamber equipped with the AESspectrometer. This arrangement enabled the measurement of mechanical properties and grain boundary compositions for the identical specimen. P-SEGREGATION IN Ni AND NkZO%CrP segregates to the grain boundaries in Ni and Ni-20%Cr. The P grain boundary concentration increases with ageing time. The segregation kinetics of P becomes faster at higher temperatures, higher levels of segregation are reached at lower temperatures. The P-segregation in Ni-20%Cr is slower and lower P-grain boundary concentrations are obtained with respect to Ni-P alloys. In Ni-ZO%Cr decreasing P Auger signals are observed after longer ageing times which might be explained by (i) redistribution of P from grain boundaries to dislocations (ii) because of increased grain boundary area due to forma-(iii) coverage of grain boundaries by carbides. With increasing P-bulk concentration the P enrichment at grain boundaries increases in Ni and Ni-20%Cr. The percentage of intergranular fracture rises with P-grain boundary concentration in Ni-P. In Ni--20%Cr, the percentage of intergranular fracture is determined by the penetration depth of hydrogen. S segregation was observed in Ni but not in Ni-20%Cr.around growing carbides, or tion of zig-zag grain boundaries, or C AND Cr ENRICHMENT AT GRAIN BOUNDARIES IN Ni-20YnCrIn Ni-20%Cr, segregation of C was observed which segregates much faster to grain boundaries than P. With increasing time segregated P replaces segregated C at grain boundaries and the concentration of segregated C decreases because of site competition. However, when chromium carbides start pre-cipitating at grain boundaries, the Auger signal for C (in carbide) increases with ageing time together with Cr. Therefore, at first a decrease of the C Auger signal is observed until the Cr Auger signal (at grain boundaries) increases, then the C Auger signal increases again with ageing time. The total amount of C at grain boundaries decreases with increasing P-bulk concentration. When C and Cr at grain boundaries precipitate as chromium carbide, Cr starts to diffuse to grain boundaries. The Cr Auge...

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Auf rostfreiem Stahl konnen beim Kochen von Gemiise und anderen Nahrungsmitteln gefarbte Schichten entstehen. Durch Kochversuche, AES-Untersuchungen der gebildeten Schichten und elektrochemische Versuche konnten Entstehung und Aufbau dieser Schichten nachvollzogen und aufgekllrt werden. Durch geringe Sauerstoffkorrosion wird OH-an der Stahloberfllche gebadet, hierdurch Magnesiumhydroxid gefallt und gemeinsam mit Silikaten und Phosphaten an der Oberfllche gebunden. Die lo@-200 A dicke Schicht erscheint