Reduction In Partial Pressure Research Articles

Pregrowth Ambient Gas Analysis of Czochralski Si Crystal Puller

The nature of the ambient gas during vacuum bakeout of a Czochralski silicon crystal puller was investigated by using a commercially available residual gas analyzer. The ambient pressure changes observed during bakeouts were correlated with the relevant gas profiles generated from the residual gas analyzer. The partial pressures and the percent compositions of the ambient gas species were then calculated. Among the major species found during vacuum bakeouts were , ,, and . and completely vanished within 2–4h into the bakeout, and the steady‐state ambience was composed mostly of gas. The prime source of was apparently the reduction of the fused quartz crucible by its graphite holder. The partial pressure of generated from this reaction was about 95% of the total ambient pressure. It thus seemed apparent that one way to reduce the carbon level in the ambience was by controlling the direct graphite/quartz reaction. An effort to reduce the generation of through the use of a coated graphite crucible holder resulted in the reduction of partial pressure by 45%. Neither the species with a mass greater than 44 amu nor the fragments of hydrocarbons associated with vacuum grease and pump oil were found in the ambience.

REACTION ENHANCED VAPORIZATION OF MOLTEN SALT

Vaporization of molten salts results in serious problems in the operation of many combustion systems. Salt vaporization of special importance in the burning of kraft black liquor, where combustion occurs in a molten Na2S/Na2CO3 environment. In this paper, it is shown that the vaporization of alkali carbonate during air oxidation of Na2S/Na2CO3 results from Na oxidation in the gas phase. Oxidation of Na in the gas phase significantly lowers the partial pressure of Na. Since the driving force for vaporization is the difference between the equilibrium vapor pressure of Na at the gas-melt interface and the partial pressure of Na in the gas phase, this reduction in partial pressure of Na significantly increases Na vaporization rates and allows fuming to proceed with only mild reducing conditions in the melt.

Inert gases in the kidney: influence of the countercurrent multiplication of sodium.

SummarySmall, but significant, partial pressure differences between urine and blood can be detected, indicating that in passage through the kidney N2 tension is reduced by 1·35% (7 mm Hg) whereas argon tension is increased by 0·77%. This differential behaviour is viewed as an inevitable side effect of the countercurrent multiplitation of sodium in the medulla given the known propensity of electrolytes for increasing the chemical potential of non‐polar solutes, i.e. the salting‐out effect. The primary event in sodium multiplication— removal of sodium from the ascending limb of Henle's loop—is then of necessity accompanied by a local reduction in partial pressure of dissolved gas. This initiates a chain of events culminating in active countercurrent attenuation of partial pressure, the effect being greater for the gas with the greater diffusivity (N2). The multiplication of sodium which parallels this attenuation tends also to offset it: increased salt concentration of necessity potentiates partial pressure through a direct salting‐out effect. The net result is a dynamic balance determined for each gas by its diffusivity and salting‐out factor. Because there is an equilibrium between inner medulla and urine (verified for hydrogen gas) these changes in the inner medulla are also reflected in the urine, This analysis is supported by a single‐loop model which predicts a value for maximal sodium concentration in the inner medulla reasonably close to physiological values (particularly if the contribution of urea to salting‐out is included). Low values of helium in urine found during inhalation experiments were also consistent with the model, although there were indications that attenuation takes several hours longer than potentiation for completion. The implications for acute (non‐steady state) experiments are that urine concentrations of non‐ electrolytes will tend to be elevated with respect to blood, a probable example of this being the ethanol concentration of urine in forensic studies.

Brisket disease: II. Clinical features and hemodynamic observations in altitude-dependent right heart failure of cattle

In cattle grazing during the summer months at altitudes between 8,000 and 12,000 feet (2,500 to 3,700 meters) in Utah and Colorado severe congestive heart failure develops. The disease is apparently the consequence of severe pulmonary hypertension which develops in this species in response to moderate altitudes. This form of chronic mountain sickness has many similarities to pulmonary hypertensive heart disease in man. It differs from Monge's disease in certain significant aspects. It is assumed that the peculiar structure of the pulmonary vascular bed in this species causes an excessive vasoconstrictive response at a reduction in partial pressure of oxygen which is still easily tolerated by man.

RATIO OF SICKLE-CELL ANEMIA HEMOGLOBIN TO NORMAL HEMOGLOBIN IN SICKLEMICS

It has been observed that all of the erythrocytes of individuals with sickle-cell trait undergo sickling and that a greater reduction in partial pressure of oxygen is required to produce complete sickling in sickle-cell trait erythrocytes than in those of sickle-cell anemics (1). These observations indicate that each sicklemia erythrocyte contains both normal hemoglobin and sickle-cell anemia hemoglobin. In a pooled sample of blood from five sicklemic individuals the ratio of t,he abnormal to the normal hemoglobin was found to be 39:61 (7). In the light of this knowledge it was considered pertinent to ascertain the extent of the variation of the ratio of sickle-cell anemia hemoglobin (SCA hemoglobin) to normal hemoglobin in sicklemic individuals and the effect of various factors on this ratio. Such information not only would increase the knowledge of sickle-cell disease but also might shed some light on the general problem of the control of hemoglobin anabolism.