New Evaluation of Water Repellency of Wood by Contact Angle

A new method for laboratory evaluation and screening of water repellency of preservative-treated wood surfaces is outlined. The method consists of the measurement of the contact angle of a small volume of water resting on the surface of the wood, under exactly defined, reproducible conditions.The changes of contact angle plotted against the time of exposure (until the water disappears in the tested surface) provide a "water-repellent curve." An area between this curve and both coordinate axes (so-called "water-repellent area") is measured in minute-degrees and provides a basis for the water-repellency rating. An empirical rating is proposed in eight grades from zero repellency to absolute repellency.The method is applied to the grading of white spruce and red pine treated with various water-borne preservatives and to white spruce treated with a methylene chloride solution of pentachlorophenol

Distribution of Toxic Elements in Douglas-Fir Plywood Treated with Czaa Preservative

Fifteen Douglas-fir plywood panels were treated with a copper-zinc-arsenic additive preservative (CZAA) in an ammoniacal solution in a full-cell process. Individual plies from the centers of the treated panels were assayed for CuO. ZnO, and As2 O5 on the basis of Cu, Zn, and As content by atomic adsorption spectrophotometry. Retentions of preservative oxides and their distribution in the plies as judged from copper-containing compounds indicated that treated panels could be well protected against biodegradation.Microscopic identification of species revealed that inner plies were made from fir, spruce, and hemlock. The preservative in them, monitored by copper-containing compounds, was evenly spread in the core plies

Probing jet properties via two particle correlation method

The formulae for calculating jet fragmentation momentum, $$, and parton transverse momentum,$$, and conditional yield are discussed in two particle correlation framework. Additional corrections are derived to account for the limited detector acceptance and inefficiency, for cases when the event mixing technique is used. The validity of our approach is confirmed with Monte-carlo simulation.Comment: Proceeding for HotQuarks2004 conference. 11 pages, 8 figures, corrected for typo

Large Angle Hadron Correlations from Medium-Induced Gluon Radiation

Final state medium-induced gluon radiation in ultradense nuclear matter is examined and shown to favor large angle emission when compared to vacuum bremsstrahlung due to the suppression of collinear gluons. Perturbative expression for the contribution of its hadronic fragments to the back-to-back particle correlations is derived. It is found that in the limit of large jet energy loss gluon radiation determines the yield and angular distribution of | Delta phi | > Pi/2 di-hadrons to transverse momenta pT2 of the associated particles. Clear transition from enhancement to suppression of the away-side hadron correlations is established at moderate pT2 and its experimentally accessible features are predicted versus the trigger particle momentum pT1.Comment: 5 pages, 3 figures. Figures 1 and 2 and some of the text revised. Footnote added. As published in Phys. Lett.