Effect of harvest time and drying on supersweet sweet corn seed quality

A supersweet sweet corn hybrid, Pacific H5, was grown under field conditions in South-East Queensland to study the effects of harvest time and drying conditions on seed quality. Cobs were harvested at different times to obtain seed with two moisture percentage ranges (20-30% and 40-50%) and dried to 12% moisture under different combinations of drying temperatures (30 degrees C, 40 degrees C and 50 degrees C) and air velocities (1.25 m/s, 2.75 m/s and 4.30 m/s). Dried seed was stored at 30 degrees C with bimonthly monitoring of seed quality for 12 months. For standard as well as cold test germinations, statistical analysis yielded significant main effects for temperature, air velocity and harvest moisture content and significant interactions for drying temperature by harvest moisture and drying temperature by air velocity. Germination at the beginning of storage was unaffected by drying temperatures up to 40 degrees C regardless of harvest moisture but was lower at 50 degrees C for higher moisture. However, germination at the end of the storage period of 12 months was greatest for seed harvested at higher moisture and dried at temperatures up to 40 degrees C. Germination was not affected by air velocity for drying temperatures up to 40 degrees C but at 50 degrees C it generally decreased with increase in air velocity. To slow down seed deterioration during storage, it is recommended that sweet corn seed should be harvested at a higher moisture range (40-50%) and dried at 40 degrees C and 4.30 m/s air velocity. The drying temperature can be raised to 50 degrees C for seed harvested at a low moisture range (20-30%) provided the air velocity is kept low (1.25 m/s).

Comparative atmospheric corrosion of primary and cold rolled copper in Australia

Atmospheric corrosion tests, according to ASTM G50, have been carried out in Queensland, Australia, at three different sites representing three different environmental conditions. A range of materials including primary copper (electrosheet) and electrolytic tough pitch (traditional cold rolled) copper have been exposed. Data is available for five exposure periods over a three year time span. X-Ray Diffraction has been used to determine the composition of the corrosion products. Corrosion rates have been determined for each material at each of the exposure sites and are compared with corrosion rates obtained from other long term atmospheric corrosion test programs. Primary copper sheet (electrosheet) behaves like traditionally produced cold rolled copper (C11000) sheet but with an increased corrosion rate. This difference between the rolled copper samples and the primary copper samples is probably due to a combination of factors related to the difference in crystallographic texture of the underlying copper, the morphology and texture of the cuprite layer, the surface roughness of the sheets, and the differences in mass. These factors combine together to provide an increased oxidation rate and TOW for the electrosheet material and which is significantly higher at the more tropical sites. For a sulfate environment (Urban) the initial corrosion product is cuprite with posnjakite and brochantite also occurring at longer exposures. Posnjakite is either washed away or converted to brochantite during further exposure. The amount of brochantite increases with exposure time and forms the blue-green patina layer. For a chloride environment (Marine) the initial corrosion product is cuprite with atacamite also occurring at longer exposures.

Bifurcations in the non-dissipative dynamics of ultra cold atoms

We present the first experimental observation of several bifurcations in a controllable non-linear Hamiltonian system. Dynamics of cold atoms are used to test predictions of non-linear, non-dissipative Hamiltonian dynamics.