The hydrolysis of soap solutions. IV. The composition of acid potassium laurates and acid sodium oleates as determined by conductivity measurements

The effect of excess lauric and oleic acids on the conductivity and on the pH of 0.2–0.02N potassium laurate and 0.1–0.01N sodium oleate systems was observed. The decrease in the specific conductivity corresponded with the formation of the acid soaps, 2KL·HL, KL·HL, 2NaOl·HOl, NaOl·HOl, and the mixed soaps 2KL·HOl and 2NaOl·HL. The mixed soaps resemble the oleates in appearance. All of these systems, even with 100 or 150 moles per cent excess acid, were slightly alkaline.     

Diffraction of X-rays by aluminum dilaurate and aluminum distearate

Summary The aluminum di-soaps appear to have a crystal structure analogous to the sodium soaps, that is, the metal atoms are arranged in a double layer from which the fatty acid radicals extend in opposite directions, end to end. Hence in the aluminum di-soaps the two acid radicals attached to any aluminum atom lie side by side. Aluminum di-soaps produced by precipitation and extraction at higher temperatures have a monoclinic angle of 48°. Those produced at low temperature and extracted at low temperature have a higher value, β, of 60°. Bristol-Myers Company post-doctorate fellow in chemistry; now associate professor of chemistry, University of Alabama.     

Arousal, monotony, and accidents in line driving.

Lack of alertness in monotonous work situations may result from lowered arousal induced by restricted and repetitive stimulation. Line driving is held to be monotonous in this sense, hence laboratory evaluation of a driver's resistance to monotony should predict his accident record. A highly repetitive, 42-min paced task was performed under controlled conditions by 20 line drivers. Self-reports on monotony susceptibility, intelligence test scores, and peer ratings were obtained. Supervisory ratings, traffic convictions, and objective driving measures were criteria in addition to accident records. Accidents of 1 type were predicted by task errors (r = .63; p     

An evaluation of extraction techniques for the fractionation of copper and lead in model sediment systems

Model sediments were used to evaluate four extraction methods for fractionation of metals in sediment: 1. dilute HNO₃ (total specifically-adsorbed metal); 2. 1 M NH₄Cl (ion-exchangeable); 3. H₂O₂ (organic); 4. density separation using bromoform. The studies indicated that dilute HNO₃ could not remove all the lead from MnO₂, that intercomponent interferences prevented 100% removal by H₂O₂ and NH₄Cl, and that density separations could not separate oxide coatings from clay minerals.     

Boundary layer instability of the natural convection flow on a uniformly heated vertical plate

Direct numerical simulation is employed to investigate the two-dimensional boundary layer instability of a natural convection flow on a uniformly heated vertical plate submerged in a homogeneous quiescent environment. A Boussinesq fluid with Prandtl numbers of Pr = 0.733 (air) and 6.7 (water), in the local Rayleigh number range 0 ? Ra_x ? 2.4 × 10¹⁰, is studied. Controlled low amplitude numerical disturbances introduced into the base flow excite unstable travelling waves, with the resulting waves tracked and analyzed as they travel up the boundary layer. The numerical simulation readily reproduced what is predicted by the parallel linear stability theory for the two dimensional mode relatively short wave spectrum, but not for some parts of the long wave spectrum. Critical Rayleigh numbers have been obtained separately for both the temperature and velocity signals using the numerical results, and shown to be in good agreement with each other provided the data is renormalized using the boundary layer scalings of Sparrow and Greg [1]. It has been shown that the disturbance behavior depends on the Prandtl and Rayleigh numbers, the excitation frequency and to a lesser extent the prescribed thermal coupling at the plate.     

Target-specific expression of presynaptic mossy fiber plasticity

Mossy fiber synaptic transmission at hippocampal CA3 pyramidal cells and interneurons was compared in rat brain slices to determine whether mossy terminals are functionally equivalent. Tetanic stimulation of mossy fibers induced long-term potentiation in pyramidal neurons but was either without effect or it induced depression at synapses onto interneurons. Unlike transmission onto pyramidal neurons, transmission onto interneurons was not potentiated after adenosine 3',5'-monophosphate (cAMP) activation. Furthermore, metabotropic glutamate receptor depression of transmission onto interneurons did not involve cAMP-dependent pathways. Thus, synaptic terminals arising from a common afferent pathway do not function as a single compartment but are specialized, depending on their postsynaptic target.     

The solubility of heavy metal soaps in co-solvent mixtures of chloroform and propylene glycol

Summary The solubilities of the myristates, laurates, palmitates, and stearates of magnesium, lead, calcium, barium, and zinc have been measured at 25° C. in chloroform and in propylene glycol and in their mixtures. Even where they are sparingly soluble in the solvents separately, they dissolve freely in mixtures of the two. For each metal the solubility is greatest for laurate and least for stearate and it is very low for zinc soaps, particularly zinc stearate. Heavy metal soaps may be directly titrated with acid in mixtures of propylene glycol and chloroform using thymol blue as indicator (yellow to pink).