Iron deficiency is difficult to control in orchards where soils have high alkalinity.
The moisture content of the stones was also varied, as this is difficult to control in real case studies.
Renewable resources, in contrast to conventional fossil resources, are more difficult to control in time and space.
Patients with Alzheimer disease have a behavior known as "sun-downing" where they become more aggressive and difficult to control in the evening.
He figured the chessboard would be more difficult to control in Game 7. "To expect the same thing is unrealistic," he said.
In searching for an aircraft that could be slowed down in flight and landed vertically, experimenters built many prototypes that were difficult to control in flight.
For TIRF-based illumination, the penetration depth dramatically depends on the illumination angle, which is difficult to control in most common setups.
However, although random tiling networks are studied increasingly, their degree of randomness (or partial order) has remained notoriously difficult to control, in common with other supramolecular systems.
The wage bill, notoriously difficult to control in the Premier League, almost doubled, from £17.4m in 2010-11, whincludeduded the players' end-of-season promotion bonuses, to £34.6m last year.
Small scale modelling has been employed as a means to understanding masonry structural behaviour over the years, because testing prototype masonry structures is both costly and difficult to control in terms of instrumentation.
A new method to measure the total energy density of waves traveling in opposite directions in ducts is suggested in order to completely eliminate phase errors that lead to bias errors and are difficult to control in industrial tests.
