Interfacial reaction and mass transport of the components in the Al2O3-TiN system during sintering

Conclusions Results of x-ray phase analyses have shown that Al₂O₃-TiN composites produced by nitrogen and vacuum heat treatment and hot pressing retain a two-phase structure at temperatures of up to 2300°K. The changes exhibited by the Al₂O₃ and TiN lattice parameters may be indicative of oxidation and subsequent dissolution of the resultant titanium oxides both in alumina and in titanium nitride. The extent of this reaction depends on the method and conditions of heat treatment.Translated from Poroshkovaya Metallurgiya, No. 11(275), pp. 32–38, November, 1985.     

Charge selectivity of peritoneal transport in CAPD patients under stable states and during peritonitis

To investigate charge selectivity of peritoneal transport in CAPD, dialysate/plasma concentration ratios (D/P) were calculated for creatinine (Cr) and 3 amino acids with almost the same molecular weight but quite different charges: glutamic acid (Glu: negatively charged), glutamine (Gln: near neutrally charged) and lysine (Lys: positively charged). The study population consisted of 23 stable patients and 11 patients with peritonitis on CAPD. In the stable patients, the samples of dialysate were taken at 2 and 4 hours and blood samples were obtained at 4 hours after the infusion of 2 liters of 2.27 or 2.5% glucose CAPD dialysate; the samples of patients with peritonitis were obtained at 4.1 +/- 1.1 hours of dwell time. In stable patients, D/P of Glu was much lower than the values for Gln, Lys and Cr at both 2 and 4 hours (p < 0.01), and D/P of Lys was significantly lower than that of Gln (p < 0.01). There was no significant difference in D/P between Gln and Cr. In patients with peritonitis, D/P of Glu was also significantly lower than the values for Gln and Cr (p < 0.05 and p < 0.01), however, no significant differences were found between D/P of Lys and the values of Glu and Gln. Ratios of both [D/P Glu]/[D/P Lys] and [D/P Glu]/[D/P Gln] were much higher in peritonitis patients than in stable patients. In conclusion, peritoneal transport in stable CAPD patients shows charge selectivity, and the order of molecular charge for transperitoneal mobility among small solutes is neutral > positive > negative. The selectivity, however, is decreased or lost during peritonitis.     

Bronchial cytologic changes during cardiopulmonary bypass: iron transport by histiocytes in low flow states

We previously reported (1) that tracheobronchial secretions of patients in hemorrhagic shock contained significantly more iron laden histiocytes than secretions of matched controls and demonstrated by histiologic studies in rats bled to hemorrhagic shock that these animals' lungs contained significantly more iron laden histiocytes than those of a control group. Two explanations appeared plausible: 1) abnormal hemoglobin breakdown products of systemic hypoperfusion during shock (2, 3, 5) may have accumulated in the pulmonary circulation where they were phagocytozed by pulmonary histiocytes, or 2) circulating iron laden histiocytes may have been arrested in the lung, which is well known to act as a filter during low-flow states (4). The present study reports on assay of bronchial secretions of 12 open-heart surgery patients under cardiopulmonary bypass from specimens obtained 1) immediately after onset of anesthesia; 2) during; and 3) after termination of cardiopulmonary bypass. The percentage of iron laden histiocytes rose from 15.6+/-6.0 after intubation, to 49.6+/-6.8 after 1 hour on bypass with occluded pulmonary arteries (p less than 0.0025), remaining close to the latter value after pulmonary circulation was restored. Hypoperfusion, accumulation of metabolites, or falling pH at the tissue level are probable explanations for these findings.     

Anodic behavior of the NiO-Fe2O3-Cr2O3-Cu composite during the low-temperature electrolysis of aluminum

In order to fabricate oxide-metallic composites with the composition 25.3NiO-41.2Fe₂O₃-13.5Cr₂O₃-20.0Cu (wt %), the temperature and duration of sintering (1350°C, 30 min) that ensure the formation of the solid solution of chromium oxide in nickel ferrite have been determined. This material is tested as an anode for the electrolysis of the low-temperature solution with the composition 12.0NaF-36.8KF-51.2AlF₃ (wt %), which was saturated with Al₂O₃ (t = 800°C). The amount of gaseous oxygen evolved on the anode was measured. It is shown that the main reaction on an anode at current density i = 0.015–1.0 A cm^?2 is the oxidation of oxygen-containing anions from a melt with the formation of gaseous O₂ and a substantial increase in the oxidation rate of the composite anode is observed at i > 1.0 A cm^?2. The voltage across the electrolyzer (4.5 ± 0.5 V) and the anodic potential (2.43 ± 0.2 relative to the Al reference electrode) during a prolonged experiment (for 89 h, i = 0.4 A cm^?2) indicate a stable and acceptable electrical conductivity of the material, while the dissolution rate, which was calculated by the weight loss (0.6 kg/yr) and volume loss (0.7 cm/yr), satisfy the requirements to inert anodes.