Considering the diffusion welding of the following material combinations, how easy would it be to produce welds in each case? Explain your answer in each case. a. Pure aluminum (AA1100) to aluminum alloy AA6061
b. Ti–6Al–4V to Ti–6Al–6V–2Sn
c. Ni-base Alloy 625 to Alloy 625
d. AISI 304 austenitic stainless steel to AISI 304.

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?

At 12 noon, the count in a bacteria culture was 400; at 4: 00 pm the count was 1200 let p(t) denote the bacteria cou population growth law. find: (a) an expression for the bacteria count at any time t (b) the bacteria count at 10 am. (c) the time required for the bacteria count to reach 1800.

Draw the engineering stress-strain curve for (a) bcc; (b) fcc metals and mark important points.