Particle flow in a jet

The angular distribution of hadrons in a jet is evaluated in perturbative QCD. The predictions are restrictive in the sense they do no depend on the details of the non-perturbative process. The distribution depends on only one phenomenologically adjustable parameter, a cutoff massQ ₀ (in addition to the universal QCD mass-scale ). The fit of the leading order prediction to the TASSO data is obtained withQ ₀270 MeV.The low value ofQ ₀ supports the hypothesis of local partonhadron duality. The particle flow in a gluon jet is also analysed.     

Structure of 2,2′-bis(3-allyl-4-cyanatophenyl)isopropylidene

The structure of the title compound (I) was determined by direct methods using MoK diffractometer data, and refined by full-matrix least squares toR=0.066 for 1536 reflections (I3 (I)). The structure shows a central tetrahedral carbon atom surrounded by two methyl and two 3-allyl-4-cyanatophenyl groups. The geometry of the cyanato group in this molecule compares well with those in 2,2-bis(4-cyanatophenyl)isopropylideneII) and 4-chloro-3,5-dimethyl-phenylcyanate (III), the only other examples of organic compounds bearing the cyanato moiety in the Cambridge Crystallographic Database (V.3).     

Preconcentration of low levels of americium and plutonium from waste waters by synthetic water-soluble metal-binding polymers with ultrafiltration

A preconcentration approach to assist in the measurement of low levels of americium and plutonium in waste waters has been developed based on the concept of using water-soluble metal-binding polymers in combination with ultrafiltration. The method has been optimized to give over 90% recovery and accountability from actual waste water.     

Nitration studies of naphtho[2,3-c][1,2,5]thiadiazole

Nitration of naphtho[2,3-c][1,2,5]thiadiazole gives the 5-nitro derivative in 61–66% yield. Chlorination of this product apparently gives an unstable addition product which loses hydrogen chloride on recrystallization to give 4-chloro-8-nitronaphtho[2,3-c][1,2,5]thiadiazole. Thus, naphtho[2,3-c][1,2,5]thiadiazole under nitrating conditions behaves as a 2-substituted naphthalene rather than as an anthracene analog.     

Statistical techniques in activation analysis

Technical methods involved in activation analysis have received widespread publicity during recent years. Even more recently, various statistical techniques have been employed in conjunction with such technical methods in order to provide a better means of estimating the amounts of various pure chemical elements contained in an unknown mixture. In particular, the method of “least squares” has been employed extensively. However, for the most part, usual least squares applications in activation analysis have utilized the ordinary matrix model Y = Xβ +ρ, under the “error” assumptions (a) zero means, (b) variances proportional to Y and (c) zero covariances. In addition to the fact that assumptions (b) and (c) may lead to erroneous results, previous applications allow only point estimation, with no provision for confidence intervals and tests for model goodness of fit. The present paper is concerned with a feasible iterative estimation procedure which eliminates the necessity for assumptions (b) and (c), and which allows construction of confidence intervals and a test for model goodness of fit. A numerical example of the application of the technique is included. Further, an indication is given of how the technique can be extended to apply in the case of “restricted” least squares (quadratic programming).