No abstract

No abstract

The second dissociation constant of sulfuric acid in 1 m KCl media has been determined from 25 to 200 °C using Debye–Hückel equation from the data on the electromotive force of a hydrogen ion-concentration cell. The thermodynamic values for the HSO4−=H++SO42− reaction and the KSO4− ion-pair association constant are also presented.

Elevated parathyroid hormone (PTH) levels and hyperphosphatemia are thought to be associated with the development of calciphylaxis. We report a patient on hemodialysis who developed proximal calciphylaxis with consistently low PTH levels after parathyroidectomy. A 31-year-old man was admitted to our hospital because of abdominal skin ulcerations. Calciphylaxis spread to the penis, and simultaneous progressive lung calcification was evident on chest X-ray, suggestive of pulmonary calciphylaxis on 99m Tc-methylene disphosphonate scintigraphy. The patient died of respiratory failure despite intensive treatment including hyperbaric oxygen therapy. This is the first report of a patient on hemodialysis who developed calciphylaxis involving the penis after parathyroidectomy. (Internal Medicine 43: 63-68, 2004)

Equilibria in aluminium sulfate solutions with a 1 mol kg−1 KCl medium and low pH range have been investigated by means of acidity measurements with a hydrogen ion concentration cell from 25 to 125 °C. The results were treated with a nonlinear least squares computer program to analyze the equilibrium constants for aluminium complexes by using a single parameter type of Debye–Hückel equation. The log(K/mol−1 kg) values of the formation constant for the reaction, Al3++SO42−\ightleftarrows[AlSO4]+ varied from 3.35 at 25 °C to 5.34 at 125 °C and were formulated as a function of temperature. The standard enthalpy and entropy of the complex formation computed from the variation of the formation constant with temperature are presented over the experimental temperature range. The species [Al(SO4)2]− was not detected under the present conditions.

No abstract

This paper deals with an experimental evaluation of bending fatigue strengths for hobbed, forged, sintered and austempered ductile iron (ADI) spur gears. The module is 2.5 and the number of teeth is 26 in the test gears. The materials of the test gears are SCr420H for hobbed and forged gears, prealloyed powder metal with 1.5 wt.% Mo for sintered gears, and FCAD 1100-15 for ADI gears. All gears except ADI gears were carburized. The pulsator bending fatigue tests were carried out for the test gears. Then the relationship between the strength and the manufacturing cost is obtained. The forged gear has the high strength of 3% and low cost compared with the hobbed gear. It is the best among the four gears. The sintered and ADI gears have approximately half the strength and cost of the hobbed gear. These gears are effective when cost is a high priority. In the progress of the fatigue tests, comparisons of strength among gears having different tooth-root forms were needed. The nominal stress obtained from actual measured profile data using a noncontact-type measuring machine is suitable for comparing the fatigue strength in gears having different root forms.

No abstract