Erosion control of riverbank is frequently necessary to protect human investments situated along rivers.
This is not always the case, and in exact treatments of these equilibria two modifications are frequently necessary.
Structured treatment programs, including inpatient, residential and day treatment, are frequently necessary to help patients interrupt life-threatening behaviors.
The technology was first used in laptops developed for military use, where computing at night or in low light is frequently necessary.
In implementing a marketing program, however, it is frequently necessary to treat demographics as the sole variable of interest (except in copy formulation).
However, it is frequently necessary to measure also an optical parameter, such as the absorption of ultraviolet light, as a function of depth in the centrifuge tube.
It is frequently necessary to carry out some preparatory treatment before the application of other finishing processes to the newly constructed fabric.
Mending, frequently necessary for woollens and worsteds, eliminates such defects as holes or tears, broken yarns, and missed warp or weft yarns.
For that reason, and because it is often more convenient to work with shorter bar lengths, it is frequently necessary to splice bars in the field.
However, few software engineers and human computer interaction engineers are aware of this important constraint and as a result avoidable rework is frequently necessary.
It is frequently necessary in machine design to provide some means of containing or limiting the flow of fluid from one region to another.
