1. Given the following conditions, calculate both the hourly ownership and operating costs: • A $900,000 single-engine scraper will be used 2,000 hours per year under average operating conditions. Tires for the scraper cost $100,000 and they last for 4,000 hours. The scraper will reach the end of its useful life with $150,000 salvage value. Interest (4%), taxes (3%), insurance (2%), and storage (1%). The flywheel horsepower of the scraper diesel engine is 500 HP. Diesel fuel costs $4.0/gallon. Operator wage is $50/hr including fringe benefits.

Calculate the cost per cubic yard to place concrete using each of the alternatives described. The work in both cases consists of placing 140 cubic yards of concrete in footings. a. Using a crane and bucket at a price of $225 per hour, including an operator, with a crew consisting of 6 laborers, a cement finisher, and a foreman. The concrete will be placed in 7 hours using this setup, and transportation of the crane costs $390. b. Using a concrete pump at a price of $295 per hour, including an operator and a crew consisting of 5 laborers, a cement finisher, and a foreman. With this setup, concrete is placed in 6 hours and transportation of the pump costs $290.

Two materials, A and B, are to be separated using two unit operations, 1 and 2. The feed has 10 tons/h A and 4 tons/h B. The split (fraction of material rejected by each operation) is given in Table P5-14. a. Which sequence of operations, (l?2) or (2?1), will yield the greatest recovery of material A? b. What will be the purity of material A using that sequence? c. What will be the efficiency of separation for the entire process train with regard to material A using the Worrell-Stesed equation?

The cost of transportation of materials has to be allowed for in the estimate, but this item is not usually measured or even referenced in the takeoff. List six other similar items.