Hardening off

All young plants grown under cover must be acclimatized gradually to the cooler and less humid conditions outside. This is known as "hardening off." The best place to do this is in a cold frame, but you can also cover plants with a cloche or fleece and remove it gradually over a few days. 

Valsa canker is a fungal disease that enters through injured bark. To prevent bark damage, make sure trees harden off in the fall by avoiding late-season fertilization or pruning. Also plant in well-drained soil and paint trunks with white latex paint diluted with an equal amount of water to reduce bark-damaging... 

Trees and shrubs that are fertilized too late in summer, or overfertilized with nitrogen at any time, do not harden off with the approach of cold weather in autumn. Pruning or ovcrwatcring too late in the summer can also cause a late flush of succulent growth. In the winter, insufficiently hardened plants may experience cold damage and subsequent disease problems, such as Cytospora canker, also known as Valsa canker, of peach trees. 

The cellulose acetate is hydroly2ed ia solution at 40—50°C for varying lengths of time (4—20 h) until the desired DS is obtained at this point, the ester is precipitated with dilute aqueous acetic acid. The precipitate is hardened in 25—30% aqueous acetic acid, which is drained off and recovered. 

The trade-off between conductivity and formabUity, at comparable strength, is also shown in Table 23. The more dUute C1751 composition provides a higher conductivity in the mill hardened condition, but at a sacrifice in formabUity relative to mill hardened C172. 

Although direc t contactive heat transfer can provide high temperatures and heat concentrations and at the same time be small in size, its use may not always be preferable because of undesired side effec ts such as diying, contamination, case hardening, shrinkage, off color, and dusting. 

By calculating the plastic work done in each process, determine whether the bolt passing through the plate in Fig. A1.2 will fail, when loaded in tension, by yielding of the shaft or shearing-off of the head. (Assume no work-hardening.)... 

The mixture is refluxed until the reaction has proceeded sufficiently. It may then be neutralised and the water formed distilled off, usually under reduced pressure to prevent heat-hardening of the resin. Because of the presence of hydroxymethyl groups the resol has a greater water-tolerance than the novolak. 

Today s conventional drill bit utilizes three revolving cones containing teeth or hardened inserts that cut into the rock as the bit is revolved. The teeth or inserts chip off fragments of the rock which are carried to the surface with the drilling fluid. The frag-... 

Modern toothpaste has to do many things. It must have abrasives to scour off bacterial films. It must have fluorides to harden the teeth against decay. It must have a strong enough pleasant... 

How bare and high the road seemed that day, with the sky hanging like lead over the frost-hardened earth, and the becks that we could not see until we stumbled on them, so deep had they cut their way into the land. Old soldiers felt the raw wind that stung our faces and looked to the east and shook their heads. Young ones left off rubbing blisters and asked what they saw. Snow by the morrow, someone said. 

In this attempt, W. Krische coated paper with milk casein in 1897 but found that casein gets washed off with water. It was soon discovered that casein could be hardened and made waterproof by treatment with formaldehyde. 

Humphrey and Seal9 (U.S.A.) reported in 1959 detailed experiments on the ECT of sarcoma-180 tumors in nearly 500 mice. In a typical experiment, 18 test animals and 18 control animals were used the ECT was done with 3 ma current, at 6 V for 3 hours a day, for 24 days. They observed that after such a lengthy treatment, the mean volume of test tumors was about 15% of the mean tumor volume of the control group seven mice showed complete tumor regression as a result of ECT. Total regression means that the tumor has decreased progressively in volume, hardened, dropped off, leaving a new skin surface at the former tumor site. 

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