Interior sampling

Transfer the contents of a digestion flask with two or three 5 ml distilled water washings together with 0.2 ml 25 % cupric sulfate solution via the fuimel on the steam stripper to the interior sample vessel and close the stopcock D. Open the outlet E to waste and turn stopcock T1 to reconnect B and C. Pass steam until it exits at E. Meanwhile pour an excess of 40% sodium hydroxide into the (closed) fuimel at D. Use 10 ml, 20 ml or 40 ml sodium hydroxide (depending on whether 2 ml, 5 ml or 10 ml of concentrated sulfuric acid was used for the acid digestion.) If the digestion catalyst used contains mercury or mercuric oxide use instead, the same volumes of sodium hydroxide-sodium thiosulfate solution (Note 6). Use the same amount of alkali in both sample and blank determinations. 

CT offers the opportunity to examine slices through the sample non-destructively and is therefor the only method for measuring exterior and also interior part coordinates without mechanical cutting of the object. 

Since solids do not exist as truly infinite systems, there are issues related to their temiination (i.e. surfaces). However, in most cases, the existence of a surface does not strongly affect the properties of the crystal as a whole. The number of atoms in the interior of a cluster scale as the cube of the size of the specimen while the number of surface atoms scale as the square of the size of the specimen. For a sample of macroscopic size, the number of interior atoms vastly exceeds the number of atoms at the surface. On the other hand, there are interesting properties of the surface of condensed matter systems that have no analogue in atomic or molecular systems. For example, electronic states can exist that trap electrons at the interface between a solid and the vacuum [1]. 

In most cases the sample bottle has a wide mouth, making it easy to fill and remove the sample. A narrow-mouth sample bottle is used when exposing the sample to the container cap or to the outside environment is undesirable. Unless exposure to plastic is a problem, caps for sample bottles are manufactured from polyethylene. When polyethylene must be avoided, the container cap includes an inert interior liner of neoprene or Teflon. 

Diffusion of Carbon. When carbon atoms are deposited on the surface of the austenite, these atoms locate in the interstices between the iron atoms. As a result of natural vibrations the carbon atoms rapidly move from one site to another, statistically moving away from the surface. Carbon atoms continue to be deposited on the surface, so that a carbon gradient builds up, as shown schematically in Figure 5. When the carbon content of the surface attains the equihbrium value, this value is maintained at the surface if the kinetics of the gas reactions are sufficient to produce carbon atoms at least as fast as the atoms diffuse away from the surface into the interior of the sample. 

Impact of a thin plate on a sample of interest which is, in turn, backed by a lower impedance window material leads to an interaction of waves which will carry an interior planar region into tension. Spall will ensue if tension exceeds the transient strength of the test sample. A velocity or stress history monitored at the interface indicated in Fig. 8.4 may look as indicated in Fig. 8.5. The velocity (stress) pull-back or undershoot carries information concerning the ability of the test material to support transient tensile stress and, with appropriate interpretation, can provide a reasonable measure of the spall strength of the material. 

Numerical simulations offer several potential advantages over experimental methods for studying dynamic material behavior. For example, simulations allow nonintrusive investigation of material response at interior points of the sample. No gauges, wires, or other instrumentation are required to extract the information on the state of the material. The response at any of the discrete points in a numerical simulation can be monitored throughout the calculation simply by recording the material state at each time step of the calculation. Arbitrarily fine resolution in space and time is possible, limited only by the availability of computer memory and time. 

One further breaks down the secondary electron contributions into three groups SEI, SEII and SEIII. SEIs result from the interaction of the incident beam with the sample at the point of entry. SEIIs are produced by BSE s on exiting the sample. SEIIIs are produced by BSEs which have exited the surface of the sample and further interact with components on the interior of the SEM usually not related to the sample. SEIIs and SEIIIs come from regions far outside that defined by the incident probe and can cause serious degradation of the resolution of the image. 

In addition to freedom from bottoming out , most people prefer a seat which effectively provides a soft surface with a firm interior. One measure of the relationship between such surface softness and inner support is the sag factor or support factor. In one commonly used test this is obtained by dividing the force required to compress a foam by 65% of its height by the force needed to obtain 25% sample compression. This generally increases with density but is typically <2.5 for a conventional slabstock foam but >2.5 for a high-resilience foam. 

The sample eapsule is plaeed in a tight-fitting 4340 steel fixture that serves to support the eopper eapsule. Pressure from the detonation of the explosive is transmitted to the eopper eapsule through a mild steel driver plate. This plate is also lapped optically flat on both surfaces. The mild steel acts to shape the pressure pulse due to the 13 GPa structural phase transition. With proper choice of the diameter of the driver plate and beveled interior opening of the steel fixture, shock deformation of the driver plate acts to seal the capsule within the fixture. 

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