About Chemical Process and Principles Beginner
*4–160. Replace the distributed loading with an equivalent resultant force, and specify its location on the beam measured from point A.
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4–159. The distributed load acts on the shaft as shown. Determine the magnitude of the equivalent resultant force and specify its location, measured from the support, A.
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*4.1.13. Water pollution in the Hudson River has claimed considerable attention, especially pollution from sewage outlets and industrial wastes. To determine accurately how much effluent enters the river is quite difficult because to catch and weigh the material is impossible, weirs are hard to construct, and so on. One suggestion that has been offered is to add a tracer of Br ion to a given sewage stream, let it mix well, and sample the sewage stream after it mixes. On one test of the proposal you add 10 pounds of NaBr per hour for 24 hr to a sewage stream with essentially no Br in it. Somewhat downstream of the introduction point a sampling of the sewage stream shows 0.012% NaBr. The sewage density is 60.3 lb/ft 3 and river water density is 62.4 lb/ft 3 . What is the flow rate of the sewage in pounds per minute?
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*4.1.12. Ammonia is a gas for which reliable analytical methods are available to determine its concentration in other gases. To measure flow in a natural-gas pipeline, pure ammonia gas is injected into the pipeline at a constant rate of 72.3 kg/min for 12 min. Five miles downstream from the injection point, the steady-state ammonia concentration is found to be 0.382 wt %. The gas upstream from the point of ammonia injection contains no measurable ammonia. How many kilograms of natural gas are flowing through the pipeline per hour?
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*4.1.4. Figure P4.1.4 is a sketch of an artificial kidney, a medical device used to remove waste metabolites from the blood in cases of kidney malfunction. The dialyzing fluid passes across a hollow membrane, and the waste products diffuse from the blood into the dialyzing fluid.If the blood entering the unit flows at the rate of 220 mL/min, and the blood exiting the unit flows at the rate of 215 mL/min, how much water and urea (the main waste product) pass into the dialysate if the entering concentration of urea is 2.30 mg/mL and the exit concentration of urea is 1.70 mg/mL? If the dialyzing fluid flows into the unit at the rate of 1500 mL/min, what is the concentration of the urea in the dialysate?
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*4.1.3. Sludge is wet solids that result from the processing in municipal sewage systems. The sludge has to be dried before it can be composted or otherwise handled. If a sludge containing 70% water and 30% solids is passed through a dryer, and the resulting product contains 25% water, how much water is evaporated per ton of sludge sent to the dryer?
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*4.1.3. Sludge is wet solids that result from the processing in municipal sewage systems. The sludge has to be dried before it can be composted or otherwise handled. If a sludge containing 70% water and 30% solids is passed through a dryer, and the resulting product contains 25% water, how much water is evaporated per ton of sludge sent to the dryer?
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*4.1.2. The fern Pteris vittata has been shown [Nature, 409, 579 (2001)] to effectively extract arsenic from soils. The study showed that in normal soil, which contains 6 ppm of arsenic, in two weeks the fern reduced the soil concentration to 5 ppm while accumulating 755 ppm of arsenic. In this experiment, what was the ratio of the soil mass to the plant mass? The initial arsenic in the fern was 5 ppm.
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*4.1.1. You buy 100 kg of cucumbers that contain 99% water. A few days later they are found to be 98% water. Is it true that the cucumbers now weigh only 50 kg?
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**3.1.1. Examine Figure P3.1.1 [adapted from Environ. Sci. Technol., 27, 1975 (1993)]. What would be a good system to designate for this bioremediation process? Is your system open or closed? Is it steady-state or unsteady-state?
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