Gamma surface Subject

The typical activated aluminas used in water treatment are 28 X 48 mesh (0.6-0.3 mm diam) mixtures of amorphous and gamma aluminum oxide (y-AI2O3) prepared by low-temperature (300-600°C) dehydration of precipitated A1(0H)3. These highly porous materials have surface areas of 50-300 m /g. Using the model of hydroxylated alumina surface subject to protonation and deprotonation, the following ligand exchange reaction, Eq. (1), can be written for arsenate adsorption in acid solution (alumina exhaustion) in which =A1 represents the alumina surface and an overbar denotes the solid phase ... 

The radiation-induced color changes in inorganic materials (Ref 145) led to a comprehensive study by Rosenwasser, Dreyfus and Levy (Ref 148) on Na azide, which turns to brownish yellow when subjected to radiation. Subsequently, when mechanically deformed crystals of Na and K azide were irradiated with 107R gamma radiation, Dreyfus and Levy (Ref 69) observed the formation of pyramidal etch pits which occurred mainly in regions where imperfections were located at the surface. These were also evident in ammonium perchlorate crystals (Ref 255)... 

Plasticised PVC was surface modified by nucleophilic substitution of the chlorine atoms of PVC by sulphide ions in aqueous media in the presence of a phase-transfer catalyst. The modified PVC was sterilised by steam autoclaving and gamma irradiation and subjected to plasticiser extraction. Surfaces were evaluated by contact angle measurements, SEM, cell culture studies, haemolysis assay and whole-blood clotting time measurements. Mechanical properties were examined. 31 refs. 

In a subsequent study, Or and Tuller (1999) have used the pore-scale model to develop a statistical framework for upscaling from pore to a sample of variably saturated porous medium. The statistical distribution of pore sizes was modeled as a gamma distribution with the expected values of liquid configuration in pore space calculated from geometrical and chemical potential considerations within the statistical framework. One of the advantages of Or and Tuller (1999) framework is the use of measurable media properties to estimate upscaling parameters. This is accomplished by matching predicted and measured retention data subject to measured porosity and surface area constraints. 

Recycled polyamide was mixed with GRT powder of 80 mesh up to concentrations of 60 wt.% in a Brabender internal mixer and compression molded (Hassan et al., 2010). The prepared moldings were subjected to gamma irradiation for up to absorbed dose of 200 kGy. Properties of the blends as a function of the irradiation dose and GRT concentration were studied. It was shown that due to the weak interfacial adhesion, the mechanical performance of blends reduced by the incorporation of the GRT. The irradiation also decreased the tensile strength and elongation at break, although the SEM studies indicated that irradiation provided a more smooth fracture surface. 

The concentration of MEHP that was eluted from a PVC sheet subjected to gamma sterilization was approximately 600 ng/ml. In this analysis method, a piece of PVC sheet measuring 1x3 cm was soaked in 5 ml of polyoxyethylated hydrogenated castor oil, a pharmaceutical additive, and MEHP was extracted. The amount of MEHP that eluted into the 5 ml solution was 3 p,g (=600 ng/ml x 5 ml). The surface area of the PVC sheet used in the extraction was 6 cm for both sides, and the amount of MEHP eluted per unit area was 0.5 p,g/cm. The surface area of gamma... 

The SNPP reactor induced radiations would subject the spacecraft and the l C electrical and electronic components to radiation exposures larger than normally found in terrestrial nuclear applications, but they would be expected to be quite moderate compared to the Jovian radiation levels. In addition, the reactor gamma interactions at the outer surface of the reactor could knock electrons off the surface of the reactor to form an electron cloud that could travel around the shadow shield to the remainder of the spaceship. The existence of this electron radiation had not been confirmed, but needs to be evaluated for reactors which do not have significant amounts of gamma attenuation around the reactor, as would be the case with shadow shields as applied on the JIMO spaceship. 

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