Recovery of the resistivity of Pt after deformation at low temperature

The recovery occurs in 4 stages; (I) below -10 Deg (recovery 14% Dr0), (II) -10 to +90 Deg, (III) 180 to 300 Deg (recovery .apprx.40% Dr0), and (IV) 300 to 580 Deg (recovery .apprx.24% Dr0). Stage I V is due to diffusion of simple vacancies. The activation energy of Pt.in stage III is a const. at 0.66 +- 0.06 e.v. from -30 Deg to +70 Deg. The recovery behaviors of Pt and Rh are essentially the same, and different from Cu. [on SciFinder (R)

Herstel van de electrische weerstand na plastische deformatie van Pt

Mechanical, Maritime and Materials EngineeringTechnische Materiaalwetenschappe

Selectivity of carbohydrate films as influenced by their moisture content

Der Einfluss des Wassergehaltes auf die beim Trocknen pflanzlicher Säfte und Extrakte an der Flüssigkeitsoberfläche sich bildende, nahezu trockene, hydrophile Haut wurde untersucht

Volatiles retention during the drying of aqueous carbohydrate solutions

Measurements were made, at time intervals of Me2CO in an aq. droplet suspended from a wire in a current of air. As a model juice, an aq. soln. of malto-dextrin was used to form the drop, and Me2CO-14C was added to serve as a model aroma. A film formed on the surface of the drop during drying, film formation rate increasing with increase in initial carbohydrate concn. This film was permeable to water, but not to Me2CO, C6H6, EtOH, or AcOEt. It is suggested that formation of a membrane impermeable to aromas is responsible for aroma retention during the drying of droplets, and that adsorption is not involved

Diffusion coefficients of water and organic volatiles in carbohydrate-water systems

Diffusion coeffs. of water (Dw) and acetone (Da) in aq. maltodextrin increased with increasing moisture content of the maltodextrin. Log Dw and log Da were linearly related to Cw-1 and Cw-1/2, resp., where Cw is the concn. of water (kg/m3) in the maltodextrin. An almost linear relation was obtained between log D and the mol. diam. of the diffusants (H2O, acetone, AcOEt, C6H6, CCl4, camphor, and CH4), where D is the diffusion coeff. of each diffusant measured in the maltodextrin with a moisture content of 20.1%

Aroma retention during the drying of liquid foods

Factors detg. aroma retention during the drying of food liqs. were investigated by a model system. Slabs of an aq. soln. of partially hydrolyzed starch, contg. a small amt. of acetone, were dried in air and the percentage of acetone retained was measured. Acetone was lost almost exclusively during the \"const. rate\" period of drying and its rate of loss could be described in terms of a binary diffusion process. At high moisture contents, the rate of loss of a component from a drying soln. is mainly dependent on its volatility, while at low moisture contents the diffusion coeff. of the component becomes the detg. factor. Loss of volatile components will be only very slight if, at the onset of drying, the value of the dimensionless group BiwoKwo is sufficiently large. Here Biwo is the Biot no. for water transport and Kwo is the ratio of the equil. water concn. in the gas phase and the water concn. in the soln. to be dried. The min. value of the group necessary to ensure high aroma retention increases with increasing relative humidity of the drying air. This value is larger for a drop than for a slab and is equal to 22 for a droplet under normal spray-drying conditions