Compare DO concentrations obtained by different methods to the DO concentrationestimated using the Table 4500-O:I and discuss possible and probable sources of error.

In concrete work, Fuller and Thompson (1907) suggested that a dense packing of grains can be achieved if the percent finer (p) and grain size (D) are related by the following equation, where n is a constant varying in the range of 0.3-0.6. Dmax is the size of the largest grain within the soil. p=(DDmax)n100 This equation is sometimes used in roadwork for selecting the aggregates. a. For n = 0.5, show that the soil is well graded. b. If n = 0.5 and Dmax = 19.0 mm, find the percentages of gravel, sand, and fines within the soil. Use the Unified Soil Classification System.

A hydrometer test has the following result: Gs = 2.65, temperature of water = 26 C, and L = 10.4 cm at 45 minutes after the start of sedimentation (see Figure 2.25). What is the diameter D of the smallest-size particles that have settled beyond the zone of measurement at that time (that is, t = 45 min)? Figure 2.25 ASTM 152H type of hydrometer placed inside the sedimentation cylinder (Courtesy of Khaled Sobhan, Florida Atlantic University, Boca Raton, Florida)

Three groups of students from the Geotechnical Engineering class collected soil-aggregate samples for laboratory testing from a recycled aggregate processing plant in Palm Beach County, Florida. Three samples, denoted by Soil A, Soil B, and Soil C, were collected from three locations of the aggregate stockpile, and sieve analyses were conducted (see Figure 2.35). (a) (b) Figure 2.35 (a) Soil-aggregate stockpile; (b) sieve analysis (Courtesy of Khaled Sobhan, Florida Atlantic University, Boca Raton, Florida) a. Determine the coefficient of uniformity and the coefficient of gradation for Soils A, B, and C. b. Which one is coarser: Soil A or Soil C? Justify your answer. c. Although the soils are obtained from the same stockpile, why are the curves so different? (Hint: Comment on particle segregation and representative field sampling.) d. Determine the percentages of gravel, sand and fines according to Unified Soil Classification System.

According to Figure 5-20, is ii possible to completely separate one of the four materials from the other three? Explain your answer.

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?

Results from a liquid limit test conducted on a soil are given below. a. Determine the liquid limit of the soil. b. If it is known that the PI = 6.5, what would be the plastic limit of the soil? c. Determine the liquidity index of the soil if win situ = 23.8%

Repeat Problem 2.14 with the following values: Gs = 2.75, temperature of water = 21C, t = 88 min, and L = 11.7 cm. 2.14 A hydrometer test has the following result: Gs = 2.65, temperature of water = 26 C, and L = 10.4 cm at 45 minutes after the start of sedimentation (see Figure 2.25). What is the diameter D of the smallest-size particles that have settled beyond the zone of measurement at that time (that is, t = 45 min)? Figure 2.25 ASTM 152H type of hydrometer placed inside the sedimentation cylinder (Courtesy of Khaled Sobhan, Florida Atlantic University, Boca Raton, Florida)