Xylem vessels in grapevines Vitis labrusca L. and Vitis riparia Michx. growing in New England contained air over winter and yet filled with xylem sap and recovered their maximum hydraulic conductance during the month before leaf expansion in late May. During this period root pressures between 10 and 100 kilopascals were measured. Although some air in vessels apparently dissolved in ascending xy...

A research program was carried out to evaluate the chloride ion permeability of both air and non-air entrained concretes made with mineral admixtures as partial replacements of cement. Two series of investigations (Series 1 and Series 2) were carried out. The mixtures were proportioned to have 28-day strengths of 35 MPa for Series 1 and 69 MPa for Series 2. Chloride ion permeability was determi...

Core yarn was spun by introducing a PVA multifilament as the core through the yarn forming zone of a ring spinning frame and viscose fibers as the sheath containing tracer fibers. The water soluble PVA multifilament was extracted from the yarn structure. Then internal structure and properties of the hollow ring yarn was assessed and compared with those of typical ring yarns. Also, two plain fab...

Micromolar concentrations of mercury, silver, and other reagents known to react with sulfhydryl groups are shown to stimulate ATPase activity and inhibit active calcium uptake in sarcoplasmic reticulum vesicles derived from rabbit fast skeletal muscle. These effects are caused by a dramatic increase in the calcium permeability of the sarcoplasmic reticulum. Measurements of Ca2+ permeability wer...

Wood drying quality and transversal permeability of Chilean second-growth Nothofagus alpina (raulí) were evaluated. Two charges of raulí sawnwood were dried in a experimental kiln. One of the charges was prepared with sawnwood from Pinto the second one was prepared with sawnwood from Collipulli. The transverse permeability to air of the material after drying was determined. The results showed t...

Recent studies indicate that PEM fuel cell performance may be strongly influenced by in-plane permeability of the gas diffusion layer (GDL). The urrent study employs a radial flow technique for obtaining in-plane permeability of GDLs, using either gas or liquid as the impregnating fluid. A odel has been developed and experimentally verified to account for compressibility effects when permeabili...

Effects of mechanical compression and PTFE content on the through-plane gas permeability of gas diffusion layers (GDLs) of PEM fuel cells are investigated both experimentally and theoretically. A new test bed is designed and built which allows pressure drop and air flow rate measurement for various fibrous samples. The measured values are used to calculate the through-plane permeability. Variou...