Determination of alpha contaminated soil profiles using Nuclear Track Detectors

Nuclear Track Detectors (NTD's) are a useful option forin situ measurements of the distribution of alpha contamination as a function of soil depth. The contamination profile of alpha emitting elements, e.g. Pu, Am and U, can be determined by detecting their alpha emission at varying depths. This paper discusses a stake type device, containing strips of CR-39 (allyl diglycol carbonate) that can be inserted into the soil up to ten centimeters or more, depending on the firmness of the soil. The CR-39 is exposed directly to the contaminated soil for a few hours. The stake is then withdrawn from the soil, the plastic detectors recovered and the alpha tracks developed by chemical etching with KOH. The distribution of tracks can be used to determine the alpha contamination depth profile as well as for detecting hot spots. It has a sensitivity of less than a pCi/g of soil.Work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract W-7405-ENG-48.     

Radiation induced competitive chlorination

The -radiolysis of solutions of benzene and naphthalene in carbon tetrachloride has been studied to obtain information about chlorination reactions. The position of naphthalene showed a reactivity 2.5 higher with respect to benzene, while the absence of 2-chloronaphthalene among the products confirmed the relatively high activation energy required for the attack in position.     

μSR study of UTr2Si2, Tr=Co,Rh OR Pt

We have studied bySR spectroscopy the intermetallicsUTr ₂Si₂ where Tr=Co, Rh or Pt. Whereas for the Co compound we only get information on the muon localisation site, from the other two materials we obtain information on their electronic properties. We compare the characteristics of theirSR response.     

Observation of quasi-static spin dynamics in the giant anisotropic ferromagnet PrRu2Si2 by μSR spectroscopy

We report zero field and longitudinal fieldSR measurements on single crystals of the ferromagnet PrRu₂Si₂ (T _c15K). BetweenT=T _c and 250K we observe a quasi-static spin dynamics of the Pr³⁺ ion sub-lattice. BelowT _c, depending on the orientation of the initial muon beam polarisation relative to thec axis of the compound, we find either an oscillating signal or an exponential depolarisation function. These latter data allow us to get information related to the muon in PrRu₂Si₂.     

HPLC determination of pyroglutamic acid as a degradation product in parenteral amino acid formulations

Summary The aminoacid glutamine in aqueous solution and in conditions of high temperature and long term storage is partly transformed into pyroglutamic acid which exhibits potential neurotoxic effects.Commercially available aminoacid mixtures supplemented with glutamine are heat-sterilized and some losses of glutamine and formation of pyroglutamic acid may occur.The aim of the work was to set up an easy and reliable HPLC method which allows the determination of pyroglutamic acid as a degradation product of glutamine. The column was a 5 m Hypersil ODS (100×4.6 mm) and the mobile phase 100% 0.007 M phosphate buffer pH 3.5.Stability studies in different conditions of temperature and time of storage were performed on aminoacid mixture available in the commerce.