Analytical and experimental studies on stress capacity with modified wood members under combined stresses

The stress capacity of joints made of modified wood members under loading can be affected by design of joints and type of adhesive. Hence, these factors were addressed in this study by assessment of stress capacity variations in corner joints under diagonal applied compressive load induced combined stresses. The joints with mitered and butted design were constructed by application of epoxy and polyvinyl acetate (PVAc) adhesives from furfurylated wood samples with two weight percentage gains (WPGs), i.e., 20% as low level and 60% as high level. Results indicated that stress capacity in both corner joints was not significantly decreased with increasing polymerization of furfuryl alcohol (FA) in wood. Despite the high compression strength in mitered joint, the induced compression stresses were low in comparison with butted joint. The stress capacity in mitered joint bonded with epoxy adhesive enhanced with increasing the level of furfurylation. This was true for shear stress parallel to grain as well. Generally, it could be concluded that mitered joint made of furfurylated members and bonded with epoxy adhesive would be stronger than other corner joints

Analytical and experimental studies on stress capacity with modified wood members under combined stresses

The stress capacity of joints made of modified wood members under loading can be affected by design of joints and type of adhesive. Hence, these factors were addressed in this study by assessment of stress capacity variations in corner joints under diagonal applied compressive load induced combined stresses. The joints with mitered and butted design were constructed by application of epoxy and polyvinyl acetate (PVAc) adhesives from furfurylated wood samples with two weight percentage gains (WPGs), i.e., 20% as low level and 60% as high level. Results indicated that stress capacity in both corner joints was not significantly decreased with increasing polymerization of furfuryl alcohol (FA) in wood. Despite the high compression strength in mitered joint, the induced compression stresses were low in comparison with butted joint. The stress capacity in mitered joint bonded with epoxy adhesive enhanced with increasing the level of furfurylation. This was true for shear stress parallel to grain as well. Generally, it could be concluded that mitered joint made of furfurylated members and bonded with epoxy adhesive would be stronger than other corner joints

Increasing salt tolerance in Olive, Olea europaea L. plants by supplemental potassium nutrition involves changes in ion accumulation and anatomical attributes.

Abstract The effects of supplemental potassium were studied on growth, ion concentration and anatomical parameters in one year old olive trees, Olea europaea L., grown in sand culture in greenhouse at different levels of NaCl for 80 days. The experiments were conducted in a completely randomized design as a factorial. Factor one was salinity (0, 40 or 80 mM NaCl) and the second factor was potassium levels of 4 and 8 mM. Salinity caused a significant decrease in the growth of plants; however, the supplemental potassium could partly ameliorate the adverse effects of salinity on growth. Due to salinity Na + and Cl -ions accumulated and the K + /Na + ratio decreased in the plants. The lower relative water content and the higher cortex /stele ratio in plants under salinity indicate water deficit. Under salinity, however, the supplemental potassium led to lower Na + and higher K + and P concentration which probably reduced the toxicity. The ratio of cortex to stele became normal as salt-grown plants were supplemented with potassium. Supplemental potassium increased palisade cell layer thickness in leaves under salinity that may be accompanied with increased potential for photosynthesis. The results indicate that supplemental potassium can be useful in ameliorating salinity stress effects in olive plants