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Strontium-90
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COLLEGE ALGEBRA
- 18.2 Well water having a total hardness of 300 mg / L as CaCO , is softened by split treatment . A zeolite bed takes 3/4 of the total flow and produces water at a hardness of 3 mg / L . as CaCO , One - fourth of flow is directly mixed with the softened water . The zeolite bed has 28.3 m² resin capacity . The water softening capacity of the resin is 62 kg / m³ total hardness as CaCO ,. Exhausted resin is regenerated by 98 percent pure NaCl solution . The salt consumption is three times the theoretical amount and used as 4 percent salt solution . Calculate ( a ) regeneration period if 950 m³ per day of water is passed through the softener , ( b ) the hardness of the fin ishod water , and ( c ) salt consumption per regeneration cyclearrow_forward(b) A 10 kL tank of water provides water for a small village. Water is drunk from the tank at a rate of 1000 L per day, and the water is replenished at the same rate. Unfortunately, the filter/purifier for the intake water is malfunctioning. Conse- quentially the water that is replenishing the tank is contaminated; it contains 0.00125 mg/L of heavy metals. Suppose that when the contamination was discovered the tank was 3/4 full and contained a, mg of heavy metals. (i) Find a formula, A(t), for the amount of heavy metals in the tank at time t. Hint: make sure your units are consistent for all quantities. We suggest mg/kL If the concentration of heavy metals in the water is below 0.001 mg/L then the water is still safe to drink. You may assume that the heavy metals in the tank are well mixed (and thus evenly distributed) in the tank. The maintenance company has been notified, and have indicated that the they'll be on premises to service the filter/purifier in 7 days (and please make sure…arrow_forwardFor some genetic mutations, it is thought that the frequency of the mutant gene in men increases linearly with age. If m1 is the frequency at age t1, and m2 is the frequency at age t2, then the yearly rate of increase is estimated by r = (m2 − m1)/(t2 − t1). In a polymerase chain reaction assay, the frequency in 20-year-old men was estimated to be 17.7 ± 1.7 per μgDNA, and the frequency in 40-year-old men was estimated to be 35.9 ± 5.8 per μg DNA. Assume that age is measured with negligible uncertainty.a) Estimate the yearly rate of increase, and find the uncertainty in the estimate.b) Find the relative uncertainty in the estimated rate of increase.arrow_forward
- Sana masagot po lahatarrow_forwardlodine-131, with a half-life of 8.04 days, is used in the treatment of thyroid disorders. Assuming that none of the material is excreted from the body, what percentage of iodine-131 still will be present in the body one week after ingesting a small amount of material? 53.7% 54.7% 55.7% 56.7% What percentage of iodine-131 still will be present in the body 30 days after ingesting a small amount of material? 7.5% 8.0% 8.5% 9.0%arrow_forwardThe half-life of a radioactive element is the number of years it takes for an observed amount of that element to decay or degrade to another element. Suppose that an element decays according to the radioactive decay model. dA/dt = kA Then the half-life T is given by:arrow_forward
- in the treatment of prostate cancer, radioactive implants are often used. The implants are left in the patient and never removed. The amount of energy that is transmitted to the body from the implant ← rate at which is measured in rem units and is given by E=[Pordt, where k is the decay constant for the radioactive material, a is the number of years since the implant, and Po is the initial rate at w energy is transmitted. Suppose that the treatment uses iodine-125, which has a half-ife of 60.1 days. Answer parts a) through e) below. CHD a) Find the decay rate, k, of iodine-125 (Round to five decimal places as needed)arrow_forwarda 0.654 ppm/year b 1ppm/year c 0.003 ppm/year d 0.30 ppm/yeararrow_forwardSuppose a patient is injected with a certain drug, and the concentration in the bloodstream is detected by a monitor thirty seconds after injection. Suppose the peak concentration is reached around 1.3591 minutes. The concentration of the drug in the bloodstream of the patient can be modelled by c(t)= ln(2t)/t where t is in minutes and C(t) is measured in mg/cm3. Show all steps by hand that the average concentration of the drug in the patient’s bloodstream from first detected to 2 minutes is4/3 (ln 2)2, i.e., evaluate the definite integral the equation in the imagearrow_forward
- 4.arrow_forward8.1arrow_forwardThe contents of a tanker truck carrying a liquid organic waste are spilled accidentally into a small lake. The resulting initial concentration of the waste in the lake is 300 mg/l. The volume of the lake is 105 m³. A stream that flows into and out of the lake has a flow rate of 1200 m³/d. If the organic waste in solution undergoes first-order photochemical decay (r = kC) with a k value of 0.008 d-1, determine the time required for the concentration of the waste in the lake to be reduced to 10 percent of the initial value.arrow_forward
- Algebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:Cengage