The phrase "are not sufficient enough" is correct and usable in written English.
You can use it when referring to a lack of adequacy or when discussing the need for something to be improved. For example, "The fire safety protocols in place are not sufficient enough to protect the staff and customers in the event of an emergency."
However, they are not sufficient enough to mitigate against solar gain effect in warmer climates.
However, when large errors occur, most of the proposed techniques are not sufficient enough to recover the loss.
Curvelet transformation enables the detection of singularities along a curvature, while the ridgelets are not sufficient enough for the identification of curves due to their line-directional geometry.
Proactive recovery techniques such as staggered proactive recovery, rebooting a compromised node, refreshing the state of a node do not guarantee hundred percent recovery of nodes and are not sufficient enough to prevent Byzantine faults permanently.
But these treatments are not sufficient enough to minimize the migration of free radicals so as to accomplish good light fastness or otherwise these treatments do not satisfy the requirement of light fastness.
Earlier studies on Bakken formation clearly elaborated the use of velocities and strains measured on samples from the core which are not sufficient enough to optimize field development strategy using hydraulic fracturing.
Namely, downloads and even daily active users aren't sufficient enough metrics for judging apps.
Keep in mind that photos and video are instantly uploaded to Flickr and YouTube via HelioUP in case the 100MB internal memory and 4GB compatible microSD aren't sufficient enough for you.
Verona's players wanted to win, but their skills were not sufficient enough to accomplish their duty.
However, modeling the human recovery process is not sufficient enough to be applied to human reliability analysis (HRA), which requires human error and recovery probabilities.
