13 . An engineer is trying to find the Hardness of AISI (( steel )) , he got the following
reading (( 212 HV , 215 HV , 214 HV , 210 HV , 190 HV )) , so answer the following . The Vickers hardness value is

Apiping systems consists of 6 m of 6-std type k and 12 m of 4-std type k, both drawn copper tubing. the system conveys ethylene glycol at a rate of 0.013 m3/s. the pressure drop across the system is to be calculated. there are two 90° elbows in the 6-in pipe, a reduction from the 6-in pipe to the 4-in pipe and four 90° elbows in the 4-in pipe. all fittings are soldered (same as flanged) and regular. the inlet and outlet of the system are at the same height.