SALS technique

Small-angle light scattering (sals) techniques, 19 568... 

Fitz, B. and Andjelic, S., Polymer, Real-time monitoring of segmental dynamics during crystallization of poly(L(-)-lactide) by simultaneous DRS/SALS technique, Polymer, 44, 3031, 2002. 

There is no appropriate defined sterility confidence level which can be translated directly into acceptance criteria for broth fill contamination for BFS processes. The most commonly recognized acceptance criterion is a sterility assurance level (SAL) of 10 although modem aseptic filling techniques such as BFS can achieve a higher SAL. This should be reflected by broth fill results and acceptance criteria for this advanced technology. 

We are at a loss to explain the discrepancy in the BF3 enthalpies of interaction with the sulfur donors. Steric effects may be operative, but this is far from the whole story for the BCI3 interaction is much larger than BF3 with these donors. Furthermore, using the tentative ( 113)3 parameters to estimate those of ( 2115)3 , we calculate an enthalpy from E and of 11.1 k.cal mole- for the BF3-P( 2H6)3 adduct compared to a measured value of 9.5 k.cal mole i. The authors report much difficulty with the sulfur donor system, but their error estimates could not possibly account for the difference between our calculated and the observed result. The behavior of ( 2115)35 compared to ( 2115)3 is clearly inconsistent with the behavior of these two donors toward ( 2H5)sAl where both enthalpies are correctly predicted with our parameters. It may be that the BF3-( 2115)25 system has an even lower equilibrium constant than reported and is completely dissociated over the temperature range studied. (This would require a very different entropy if the — AH predicted by E and were correct.) A slight impurity (reported to be less than 0.1%) or decomposition product could interact appreciably with BF3 and changing pressure contributions from this adduct with temperature could be attributed incorrectly to the sulfur donor adduct. The actual BF3-sulfur donor adduct would then be a very common example of an adduct which cannot be studied by the vapor pressure technique because it is completely dissociated at the temperatures at which one of the components has appreciable vapor pressure. We have examined the reaction of BF3 ( 2Hs) 2O with large excess of ( H2) 4S in dichloroethane solution at 25 ° and have found the equilibrium constant to be too low to be measured calorimetrically. 

Soulier et al. (35) isolate eight triterpenic alcohols from sal and illipe butters besides other compounds. They separate these compounds after saponification of the fatty matter and fractionation of the unsaponifiable on an aluminium oxide column (hydrated at 5%). Two successive HPLC separations and a TLC-AgN03 permit the isolation of highly purified fractions. Through the use, among others, of the H-NMR and MS techniques, they identify nine... 

A rapid preseparation technique was developed for the extraction of SAL from various chicken tissues using the irradiation of the sample in EtOH-2-PrOH for 9 s in a common household microwave oven. The extract was analyzed without further cleanup and detected via postcolumn reaction with DMABA at 86°C. Recoveries ranged between 87% and 100% (105). 

In spite of all the recent success which can be traced to the three techniques, SANS, SAXS, SALS, there are serious limitations in their scope Q). For instance only average values, such as root-mean-square end-to-end distance and radius of gyration of a polymer chain can be extracted from these techniques. In other words, these techniques cannot provide information on the actual conformation or dimension of the individual polymer chain. Also since all three techniques are indirect, the analysis of the raw data is not straightforward and requires various manipulations and faith in existing theories to draw conclusions. Finally with regard to SANS, it must be noted that only a limited number of facilities in the U.S.have this capability, thus restricting its use. 

In addition to the standard discussion of the materials studied, and processing and analytical techniques employed for this work, a rather lengthy presentation on two-dimensional position sensitive detectors for SALS will be presented. A review of prior work performed by other researchers will be discussed, as well as the particulars of the detector developed for this study. Finally, a comparison between the detector presented here, and those developed previously will be made. 

Tracer techniques, for example, are used to obtain very small but representative and measurable samples of highly radioactive spent fuel solutions. One millilitre of the solution is then spiked with a known amount of uranium and plutonium tracer isotopes. A few microlitres of the spiked solution are dried and shipped to SAL. One to fifty nanograms of uranium or plutonium extracted from this tiny sample are sufficient for a complete analysis representing the composition of half a tonne of irradiated fuel with an accuracy of 0.3 to 0.5%. 

Well characterised reference materials similar in composition, shape and packaging to actual nuclear materials are necessary to calibrate non-destructive techniques or to verify their accuracy. SAL performs analyses requested for the verification of such... 

Here is how SAL works Samples are received in a reception and storage room, then routed to the appropriate wet chemical analysis laboratory. There, they are analysed for uranium, thorium or plutonium content, and purified aliquots (portions of the sample) are prepared for the isotopic analysis of three elements. Isotopic analyses are performed routinely by mass spectrometry, and radiometric techniques are used for back-up. Emission spectrography serves to detect the presence of impurities which could interfere with the measurements and thus distort the results of the chemical and isotopic analysis of uranium, thorium and plutonium. Complex calculations and quality checks are performed on minicomputers, which are connected in a network to a central laboratory mini-computer. A central laboratory data system stores and provides analytical reports and enables the quality of the analyses and the status of the flow of samples through the laboratory at any time to be monitored. 

Several ore samples were brought back to Laboratories in Seibersdorf by the inspection team the uranium content was determined by gamma-ray spectrometry and, after dissolution, by laser-excited optical fluorescence at PCI and by isotope dilution mass spectrometry at SAL. Considering the low concentration of lu-anium in the samples, the agreement between the various techniques is quite good (see Table 11.12). 

---