Write a program in Fortran to read a square matrix A (10.10), then calculate and find the following: 1 - the sum of the elements of the upper triangle of the matrix.
2- The sum of the elements of the lower triangle.
3- The sum of the main diagonal elements of the matrix.
4- The sum of the elements of the perimeter of a matrix.​

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Define thermoplastic polymers and thermosetting polymers in terms of their structures, and (ii) describe briefly a process suitable for the production of products from each type of polymer.

Consider two concentric spheres forming an enclosure with diameters of 12 cm and 18 cm the spheres are maintained at uniform temperatures ti-50°c and t2 = 250°c and have emissivities .45 and .8, respectively. determine the net rate of radiation heat transfer between the two spheres per unit surface area.