The phrase "are the main constraints" is correct and usable in written English.
It can be used when discussing limitations or restrictions in a particular context, such as a project, study, or analysis.
Example: "In our research, the budget and time limitations are the main constraints affecting our outcomes."
Alternatives: "represent the primary limitations" or "constitute the key restrictions."
These mechanical data are the main constraints for safely drilling the rock formation (Nicolás-López et al. 2012).
A shortage of and erratic nature of rainfall, frequently recurring droughts, and population growth are the main constraints affecting crop production in the study area.
Sequence-dependent setup times, fuzzy processing times and fuzzy due dates with triangular possibility distributions are the main constraints of this model.
Quick settling time and rise time to the desired output along with high efficiency, required phase margin, loop bandwidth are the main constraints on the controller.
This is an attempt towards rehabilitation of limestone mine spoils in arid areas where water and nutrients are the main constraints even in normal soil.
The mismatch between the supply and demand, inequitable distribution and the over irrigation of water consuming crops are the main constraints that are faced in the implementation of the integrated water resources management in Egypt.
Inadequate knowledge, poor veterinary services and limited availability of drugs were the main constraints that hindered the control of TBDs.
However, lower gas liquid mass transfer and production of inhibitory compounds during fermentation were noted to be the main constraints to syngas fermentation into ethanol (Munasinghe and Khanal 2010; Huhnke 2013; Lee P 2010).
In fact, credit limitations and inadequate foreign currency reserves in many developing countries appear to be the main constraints on such countries' more extensive use of futures for commodity hedging.
