Deterioration of electromotive force of chromel-alumel thermocouples in reducing atmospheres at high temperatures

The deterioration of electromotive force (emf) of Chromel-Alumel (CA) thermocouples in 80 pct H₂ + 15 pct CO + 5 pct CO₂ has been analyzed in terms of the corrosion behavior of Chromel. Emf of the CA thermocouple deteriorated drastically in 80 pct H₂ + 15 pct CO + 5 pct CO₂. After exposure for about 1000 hours at 900 °C, the decrease of emf was about 16 mV. The deterioration process could be separated into three terms. The first term, which has the smallest time constant of about 20 hours, was attributed to carbon deposition on the Chromel surface in the temperature range of 600 to 700 °C. The second term, which has a time constant of about 100 hours, was attributed to the severe internal oxidation of chromium in the temperature range of 500 to 800 °C. The third term, having the largest time constant of several thousand hours, might be attributed to the moderate and gradual preferential oxidation of chromium in Chromel in the range 800 to 900 °C. Boron nitride (BN) coating on CA thermocouples could reduce this deterioration of emf; the decrease of emf was improved to about 3 °C during 700 hours test at 900 °C.     

Effect of smoking on vascular resistance in the upper extremities

311 first-degree relatives of 78 consecutive patients with gastric carcinoma and 386 first-degree relative of control probands computer matched from a large Finnish population were studied by means of biopsies from antrum and the fundus and by functional and immunological methods. Both the A and B type of Strickland the McKay as well as the AB types of Pitchumoni and Glass were discernable in the present series and often accumulated in the same families. Particularly the A type associated with high serum gastrin values and parietal cell antibodies revealed a family accumulation. In general members of the same family tended to behave similarly with regard to morhology, function and immunology of the antro-fundal mucosa. The 386 computer matched controls from the general population were treated by means of mathematical methods derived from stochastic theory. It appeared that on a family level there was clearly discernable a line representin families with predominance of fundal gastritis (A type?) which significantly deviated from the main population. However, no such behavior was found as to the families with predominantly antral gastritis (B type?) which behaved like the population at large.     

Precision of dual energy x-ray absorptiometry in the upper extremities

Dual energy x-ray absorptiometry (DEXA) has been shown to be a precise method for measuring bone mineral density (BMD) and content (BMC) in lumbar spine and proximal femur, but it has not been widely used in other skeletal sites. The in vivo day-to-day precision of DEXA (Norland XR-26) for seven anatomic sites in the upper extremities was evaluated by twice measuring both the right and left sides in ten subjects. For consistently defined regions-of-interest, the following precision values (coefficient of variation) were obtained for BMD and BMC: 0.8% and 1.0% (proximal humerus); 0.5% and 0.5% (humeral shaft); 0.7% and 0.5% (radial shaft); 1.3% and 1.1% (ulnar shaft); 0.7% and 1.0% (distal radius); 0.7% and 1.2% (distal ulna); 0.4% and 0.6% (hand). The initially observed relative side-to-side differences did not change significantly in the repeated measurements. Our results indicate that DEXA is a precise method for assessment of BMD and BMC also in the upper extremities.     

The determination of oxygen in gas mixtures by electromotive force measurements using solid oxide electrolytes

The behavior of impervious ZrO₂+ 10 mole pct CaO electrolyte tubes was studied at 500∮ to 1100° in oxygen concentration cells of the type (−) Ar-O₂or CO-CO₂/ZrO₂-CaO/O₂(+) The equilibrium oxygen pressures imposed by Ar-O₂(1 to 10⁻⁶atm) and CO-CO₂ (10⁻⁶to 10⁻¹⁸ atm at 1000°) mixtures of known compositions were determined from electromotive force measurements. The measured and theoretical electromotive forces were compared. For Ar-O₂ mixtures, the oxygen pressures can be measured with accuracies of ±0.4 pct at 1 to 10⁻² atm and ±4 pet at 10⁻⁴ to 10⁻⁵ atm. An accuracy of ±11 pct can be achieved with CO-CO₂ mixtures. The electromotive force of the above cell increases as the gas flow rate at the anode increases at low flow rates and becomes independent of flow rate at high flow rates. The minimum flow rates required to eliminate any significant flow rate dependence are presented as a function of oxygen pressure. Formerly Graduate Student, Department of Metallurgy and Materials Science, University of Toronto, Toronto, Ontario, Canada     

Risk factors for deep venous thrombosis of the upper extremities

BACKGROUND: Hypercoagulable states and triggering factors (surgery, trauma, immobilization, pregnancy, and use of oral contraceptives) are associated with an increased risk for deep venous thrombosis of the lower extremities. In contrast, risk factors for deep venous thrombosis of the upper extremities have not been identified. OBJECTIVE: To evaluate the prevalence of hypercoagulable states and triggering factors in patients with primary deep venous thrombosis of the upper extremities. DESIGN: Frequency-matched case-control study. SETTING: Hemophilia and thrombosis center at a university hospital. PATIENTS: 36 patients who had primary deep venous thrombosis of the upper extremities, 121 patients who had primary deep venous thrombosis of the lower extremities, and 108 healthy controls. Patients who had deep venous thrombosis of the lower extremities and study controls were frequency-matched by age, sex, geographic origin, and social status with patients who had deep venous thrombosis of the upper extremities. MEASUREMENTS: Resistance to activated protein C was evaluated by a clotting method based on the activated partial thromboplastin time. If test results were abnormal or borderline, DNA analysis for substitution in coagulation factor V gene was done. Antithrombin, protein C, protein S, antiphospholipid antibodies, and total plasma homocysteine levels were also measured. RESULTS: Prevalences of abnormalities of the natural anticoagulant system (9%) and hyperhomocysteinemia (6%) in patients who had deep venous thrombosis of the upper extremities were similar to prevalences of both factors in controls (6% and 7%, respectively) but lower than in patients who had deep venous thrombosis of the lower extremities (31% and 14%, respectively). Antiphospholipid antibodies were found only in patients who had venous thrombosis of the lower extremities (7%). The overall prevalence of hypercoagulable states in patients who had thrombosis of the upper extremities (15%) was similar to that in controls (12%) but was significantly lower than that in patients who had thrombosis of the lower extremities (56%). A recent history of strenuous exercise of muscles in the affected extremity was the most frequent triggering factor for patients who had deep venous thrombosis in the upper extremities (33%). CONCLUSIONS: This preliminary study indicates that the prevalence of hypercoagulable states is low in patients who have primary deep venous thrombosis of the upper extremities.     

Detailed assessment of partial thermodynamic quantities of tin in molten Bi-Sn alloys from electromotive force measurements

All the partial thermodynamic quantities, including the activity and activity coefficient of tin,a _Sn and γ_Sn, in the liquid Bi-Sn alloys between 300 °C and 500 °C are assessed in detail from electromotive force (emf) data. The emf values were obtained from a modified molten salt electrolyte concentration cell that had extraordinary stability within +0.005 mV. The composition dependence of γ_Sn did not follow Darken’s quadratic formalism, nor did the alloy behave as a regular solution. The excess partial quantities, ΔˉH _Sn ,ΔˉS _Sn ^xs , and ΔˉG _Sn ^xs , are oscillating across the composition, and the activity curve exhibits double, positive and negative, deviations from Raoult’s law. The a_Sn, γ_Sn, and ΔˉG _Sn ^xs change from positive to negative departure from ideality in the tin-rich region beyond about x_Sn = 0.82. All those partial quantities and γ _Sn ^o , including the β° (the α function of tin) at infinite dilution, are determined accurately by means of Chiotti’s method. ROBERTO CAMISOTTI, formerly Undergraduate Student, Central University of Venezuela. Formerly Assistant Professor, Central University of Venezuela.     

Study on the inflation pressure of air tourniquets in surgery of the upper extremities

52 patients were studied under two different inflation pressure so as to find out the proper inflation pressure in the upper extremity operation. Analyzing the hemostasis effect and EMG of the upper extremity under different inflation pressre, it suggested that when the air tourniquet is used in the upper extremity operation the traditionally used pressure (33.3-40.0 kPa) of the air tourniquet should be changed according to the patient's condition. Usually good hemotasis effect could be obtained under the pressure of 4.0-6.6 kPa, which is more than the systolic pressure of the brachial artery.     

Determination of gibbs energy of formation of Ni-B-O system by electromotive force measurement using solid electrolyte

The standard Gibbs energies of formation of Ni₃B, Ni₂B, o-Ni₄B₃(Ni_0.586B_0.414), m-Ni₄B₃(Ni_0.564B_0.436), NiB, and Ni₃B₂O₆ of the Ni-B-O system have been determined by measuring electromotive forces of galvanic cells using a Y₂O₃-stabilized ZrO₂ solid oxide electrolyte. The results are as follows:

Age-associated loss of power and strength in the upper extremities in women and men

Cross-sectional and longitudinal age-associated reductions in power and isometric strength are described for the upper extremities. Over a 25-year period, repeated measures were taken approximately every 2 years from men and women in the Baltimore Longitudinal Study of Aging (BLSA). The longitudinal measures covered an average 9.6 years, range 1-25 years for men and an average 4.6 years, range 1-8 years for women. Strength and power declined beginning by age 40 in both women and men. Thereafter, power declined about 10% more than strength in men, while no significant differences were found in women. Age had a statistically independent influence on strength and power measures after adjusting for gender, height, weight, caloric expenditure, and muscle mass. Twenty-five-year longitudinal analyses in men confirmed the declines observed cross-sectionally, while no changes were observed in women over the 4-5 years of longitudinal data available. Further longitudinal studies are needed to understand the relationships between strength and power losses with age in women. The differences between power and strength changes with age in men argue for the importance of factors other than strength affecting power.     

Blood flow and venous distensibility in the upper and lower extremities of newborn infants

The electrocapacitance plethysmograph was utilized to measure peripheral blood flow and venous distensibility in 17 newborn infants and 20 adults. Measurements were made in the upper and lower extremities in each subject under identical environmental conditions. Blood flow in the forearm and calf were found to be significantly higher in infants than adults. In infants there were no significant differences in the blood flow between the upper and lower extremities. In contrast, in the adults, the blood flow was significantly higher in the upper than in the lower extremities. Similarly, venous distensibility was observed to be higher in infants than in adults. While no significant differences were observed in the venous distensibility between the upper and lower extremities in infants, the venous distensibility was found to be higher in the forearm than in the leg in adults.