An ultrafiltration system is operated to concentrate a protein solution containing a buffer. The average pressure drop across the membrane is $30$ kPa, and the fluid viscosity is $1\mathrm{.}5{10}^{-6}$kPa $s.$ With clean membranes, the transmembrane flux using buffer in the system is $110$ liters $m^{-2}{h}^{-1}$ for this pressure drop. After $2$min of operation with the protein solution, the transmembrane flux is $15$ liters $m^{-2}{h}^{-1}.$ At this point, the system is operated with the buffer only in the backflushing mode with negative transmembrane pressure until a constant transmembrane flux is reached. Then, the system is operated with the buffer in the normal mode $($positive transmembrane pressure$),$ and the steady$-$state transmembrane flux is $35$ liters $m^{-2}{h}^{-1}$ at a pressure drop of $30$ kPa. It has been determined that the flux due to the osmotic pressure difference is negligible. Estimate the irreversible fouling resistance $(R_{if})$ and resistance due to concentration polarization and a gel layer $(R_p)$ for the membrane after $2$ min of operation with the protein solution.