Mass accumulation probes

Mass accumulation probes as the name suggests, are used to obtain a deposit that can be weighed, i.e. a direct measurement of the fouling per unit area of probe for given conditions. The technique has also been used to assess corrosion under the conditions within a combustion space. 

FIGURE 17.21. Data obtained using a heat flux probe Deposition and mass accumulation probes... 

In general deposition and mass accumulation probes are similar in principle but differ in sophistication. The deposition probe is simple whereas the mass accumulation probe is likely to be more elaborate. 

A mass accumulation probe that has been used in a variety of test locations was first reported by Isdale et al [1984], The essential design of the probe is shown on Fig. 17.22. The sample collection surfaces are in the form of a simple cylindrical shell split into two identical half cylinders as shown in Fig. 17.23. The two simple half cylinders are clamped together over the end of the probe, which may be cooled with air or water depending on conditions. 

FIGURE 17.22. The National Engineering Laboratory mass accumulation probe... 

While the effect on tests requiring the interaction of the tumour cells with extra cellular matrix components suggest that the interaction of RAPTA compounds with cell surface molecules may be responsible for part of their activity, the compounds also accumulate within cancer cells and interact to a significant extent with proteins in the cytoplasm. Adduct formation of RAPTA compounds with proteins has been studied using mass spectrometric methods [10, 25, 26]. In general, rapid and irreversible binding has been observed. In a recent study the reactivity of cisplatin and RAPTA-C with a mixture of proteins was probed without using any... 

Mitochondrial toxicity may also lead to a decrease in the mitochondrial membrane potential which can be measured by various dyes, such as Tetramethylrhodamine methyl ester (TMRM), Rhodaminel23, JC-1 (Molecular Probes), and mitochondrial membrane potential indicator (m-MPI, Codex). These dyes specifically accumulate in the matrix of the mitochondria according to the Nernst equation, with an inverse proportion to the A Pmembrane [9]. Thus, upon loss of mitochondrial membrane potential, the fluorescence intensity will decrease, as shown for TMRM in Fig. 2e, f. Notably, TMRM, is not a ratio-metric dye, which means that additional controls for mitochondrial number/ mass may be required, as in contrast to the ratio-metric dyes JC-1 and m-MPI. 

The abundance ratios of heavy elements are sensitive to the initial mass function (IMF), the star formation history, and variations in stellar nucleosynthesis with, e.g., metallicity. In particular, comparison of abundances of elements produced in stars with relatively long lifetimes (such as C, N, Fe, and the s-process elements) with those produced in short-lived stars (such as O) probe the star formation history. Below, I review the accumulated data on C, N, S, and Ar abundances (relative to O) in spiral and irregular galaxies, covering two orders of magnitude in metallicity (as measured by O/H). The data are taken from a variety of sources on abundances for H II regions in the literature. 

Mass Spectrometry. Electron impact (El) mass spectrometry was done at NRL on the effluent from a 6 ft. OV-101 packed GC column programmed from 70 to 210°C. Field ionization mass spectrometry (FIMS) was performed by SRI International on contract to NRL. In this latter analysis, the fuel sample was frozen on a solids inlet probe prior to insertion into the mass spectrometer. The spectra accumulated for each mass during a temperature program were normally totaled for data presentation (6). Molecules boiling below 140°C are lost or depleted with this technique but such compounds comprise a very small fraction of JP-5 or DFM. Since the ionization efficiency for hydrocarbon classes is currently under study, the FIMS data are utilized primarily in a qualitative sense. 

These results showed that RQ can be used as a cold tracer of FQ. Indeed, in erythrocytes infected with P. falciparum, many molecules contain atoms of iron iron is the main component of red blood cells, but it is also present in the heme, in the hematin and hemozoin. The use of a probe is necessary to study the cellular accumulation of FQ. Inductively coupled plasma mass spectrometry... 

Laser-induced fluorescence is, by now, a fairly well used technique for the quantitative probing of gaseous species. The advantage of using LIF is that it can detect very low concentration products whose presence in the detonation products is suspected but that cannot be reliably detected with mass spectoscopic methods. The sensitivity advantage can sometimes be offset by its specificity, so that only a limited amount of data can be accumulated during one trial. 

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