Sample encapsulation

Along a different line of research on shock compression of solids, namely, recovery experiments, great progress was also being made. Shock-induced recovery-type chemical reactions in encapsulated samples were first reported by Riabinin in 1956. Shock-induced metallographic transformation and the observation of twin bands in iron were first reported by Smith in 1958. Another major breakthrough was the shock-induced synthesis of diamond in 1961 by DeCarli and Jamieson. 

Sensory Evaluation. The organoleptic evaluation of the samples was conducted by a paired comparison test. The expert panel consisted of six to eight members.The encapsulated samples (stored at 45 C) were evaluated against the control samples at O.IJIJ (w/w) in spring water. 

Determination of Surface Oil. A Soxhlet continuous extraction apparatus was used for removing the surface oil from the encapsulated samples. The procedures used were similar to those described previously by Anandaraman and Reineccius (16). Modifications included a reduced extraction time of 4i hours and the selection of 2-octanone as the internal standard. 

In dynamic flash combustion, the tin-encapsulated sample is dropped into the preheated furnace shortly after the flow of a 50 vol% O2/50 vol% He mixture is started (Figure 27-8). The Sn capsule melts at 235°C and is instantly oxidized to Sn02, thereby liberating 594 kJ/mol, and heating the sample to 1 700°-l 800°C. If the sample is dropped in before very much Oz is present, decomposition (cracking) occurs prior to oxidation, which minimizes the formation of nitrogen oxides. (Flammable liquid samples would be admitted prior to any 02 to prevent explosions.)... 

Impact Sensy. No explns were produced at 3m when a 10-kg wt was used to impact encapsulated samples... 

The place of DSC in a screening programme to estimate hazards in proposed chemical processes is discussed in detail. The use of pressure-tight encapsulated samples permits rapid assessment of heats of reaction and/or decomposition and kinetic behaviour under likely process conditions. Selected case studies are included... 

For therapeutical purposes, natural radionuclides, mainly Ra and Rn, were the first to be applied as external and internal radiation sources. For example, encapsulated samples of Ra have been attached to the skin or introduced into the body, and Rn has been recommended for the treatment of the respiratory tract by inhalation in radon galleries or it has been encapsulated in small thin-walled gold tubes and introduced into the body for treatment of cancer. 

The SMSI induced chemisorption suppression could be reversed in these thin film samples by heating 1n oxygen. This fact is demonstrated in Fig. 4 where the left hand panel contains CO TPD results from the previously encapsulated samples after oxidation (875 K, P ... 

Values of "dry" leakage currents for encapsulated samples which are presumed accurate and measure in the lOOpA-lnA range, should be easily verifiable by a volume resistivity measurement of the polymer, since the polymer s resistivity would have to be less than approximately lxlO1 ohms-cm. 

Figure 7.37. Melting-point temperature determination (a) encapsulated samples of 99.99999 niole- n purity thermocouple embedded directly in the sample (39).

The fabrication of encapsulated metal hydride involves 3 main steps 1) break the metal hydride to fine particles and stabilize the fines for handling in open air 2) encapsulate the metal hydride particles in silica with the sol-gel method 3) treat the composite with heat to obtain desired strength and porosity. Micrographs of a typical encapsulated sample are shown in Figure 1. 

Sulphur contents were determined using a Leco - CHNS - 932 - determinator. Samples were weighed within a silver capsule and then the encapsulated sample dropped into a furnace when the components were combusted in an oxygen excess environment. The sulphur content, measured as SO2 was then determined by IR absorption. 

To offer the highest possible neutron fluxes, research reactors often have locations in the fuel assembly grid in which encapsulated samples can be placed, often for prolonged exposure covering an operation cycle or longer times. It should be noted that sample encapsulation for such irradiations must meet very specific requirements. Due to the radioactivity of the substantial encapsulation materials, prolonged decay ( cooling ) times are necessary before the samples can be retrieved for the assays. 

Cleanliness of the instrument Instrument coolant Calibration parameters Sample pan selection Sample size Sample preparation Sample encapsulation Sample atmosphere Temperature range of interest Scanning rate... 

When encapsulating samples, it is advisable, if possible, to remove any sharp comers, sharp protrusions, and burrs... 

A variety of molds are available to encapsulate samples for embedding. BEEM type capsules are useful for small pieces of materials that can be placed in the tip which then provides pretrimmed specimen blocks. Gelatin capsules are rounded in shape and thus must be trimmed, but they have the advantage that they can be removed by soaking in water. Other shapes are good for specific sample forms. Flat embedding molds are excellent for films and membranes. 

Combust the encapsulated sample in a manner similar to the calibrant. Depending on the sample matrices, set varying oxygen flow rates and combustion times to overcome incomplete combustion. 

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