"rarely achievable" is correct and usable in written English.
It can be used to describe something that is difficult or unlikely to be accomplished. Example: "Becoming a professional artist is a dream for many, but it is a goal that is rarely achievable for the majority."
However, online capacity or resistance measurements are rarely achievable in electric vehicles.
Whereas Guyon's characterization of the highest spiritual states emphasized the annihilation of the individual's will in an act of sustained submission to the will of God, Bossuet argued that such exalted states as Guyon had taught were only rarely achievable, and he doubted that Guyon herself had experienced them.
Surgery is often extremely challenging and complete resection is rarely achievable.
Thus, a heparin-free easy-to-use anticoagulation within the dialysis circuit is needed but, to date, usual protocols (iterative saline flushes, heparin grafted membranes) lead to 20 50% of premature clotting and sessions that last greater than 240 min are rarely achievable.
However, this is reliant on the PCR result being available immediately, a situation rarely achievable in clinical practice when factors such as specimen transportation and laboratory processing are taken into account.
Ideally, every study should follow all participants until death, but this is rarely achievable.
Control of all these parameters at once is difficult and rarely seen or achievable.
When it comes to motivation and our personal victories, we rarely set realistic and achievable goals in our effort to accomplish something big in our lives -- weight loss, a new degree, a lifestyle change, a major project -- and then we don't accept the moments when we hit a plateau along the way.
Obama achieved the achievable.
However, it tends to have a very shallow dose response curve and only rarely produced >95% inhibition at clinically achievable concentrations: 6% of oesophagogastric tumours (one out of 17) and 3% of colorectal tumours (one out of 38).
Detecting lesions smaller than 2 mm is rarely possible with imaging, but might be achievable using radionuclide or doppler based perfusion techniques.
