To study the impact of ozone (O3) and O3 plus CO2 on aspen growth, we planted two trembling aspen clones, differing in sensitivity to O3 in the ground in open-top chambers and exposed them to different concentrations of O3 and O3 plus CO, for 98 days. Ozone exposure (58 to 97 microl l(-1)-h. total exposure) decreased growth and modified crown architecture of both aspen clones. Ozone exposure de...

Experimental and theoretical work has been carried out to study the longitudinal space-charge effects in a retarding field energy analyzer. A one-dimensional model for both a mono-energetic beam and a thermal beam has been developed for this purpose. The study shows that, if the current density inside the device were higher than a critical value, the longitudinal space-charge effects would dist...

We review a solution (Ref. [1]) of the cosmological constant problem in a braneworld model with infinite-volume extra dimensions. The solution is based on a nonlinear generally covariant theory of a metastable graviton that leads to a largedistance modification of gravity. From the extra-dimensional standpoint the problem is solved due to the fact that the four-dimensional vacuum energy curves ...

Simplified beam line for low energy Ion implantation is considered. Compensation of the space charge of high perveance, low energy ion beam in beam lines for ion implantation and isotope separation has been investigated. Different mechanisms of the compensating particle formation such as ionization by the beam, secondary emission of electrons and negative ions, electronegative gas admixture, an...

Conference Reports: Aspen Workshop on Numerical Investigations of Singularities in GR, Susan Scott . . . . 15 Second Annual Penn State Conference: Quantum Geometry, Abhay Ashtekar . . . . . . . 17 First Samos Meeting, Spiros Cotsakis and Dieter Brill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Aspen Conference on Gravitational Waves and Their Detection, Syd Meshkov . . . . ...

Steady State to ASPEN plus (Aspen Technology, Inc. /www.aspentech.com /) Design Complex CHEMCAD (Chemstations, Inc. /www.chemstations.net /) Chemical Processes: Design II (WinSim Inc. /www.winsim.com /) gPROMS (Process Systems Enterprise Ltd. /www.psenterprise.com /) HYSYS (Hyprotech, Ltd. /www.hyprotech.com /) PEGS (CADcentre Ltd. /www.energyweb.net/OSO/) Pro II (SIMSCI-ESSCO division of Inven...

The biochemical anti-herbivore defense of trembling aspen (Populus tremuloides Michx.) was investigated in a molecular analysis of polyphenol oxidase (PPO; EC 1.10.3.2). A PPO cDNA was isolated from a trembling aspen wounded leaf cDNA library and its nucleotide sequence determined. Southern analysis indicated the presence of two PPO genes in the trembling aspen genome. Expression of PPO was fou...

Studies on the durability and dimensional stability of a series of hardwoods and softwoods after thermal modification in vegetable oils and in steam atmospheres have been performed. Mass loss after exposure to Coniophora puteana (BAM Ebw.15) for 16 weeks was very low for European birch, European aspen, Norway spruce, and Scots pine thermally modified in a linseed oil product with preservative (...

Identification of specific genes and enzymes involved in conversion of lignocellulosics from an expanding number of potential feedstocks is of growing interest to bioenergy process development. The basidiomycetous wood decay fungi Phanerochaete chrysosporium and Postia placenta are promising in this regard because they are able to utilize a wide range of simple and complex carbon compounds. How...