One common issue with air strippers is scaling due to hardness in the water. Please design an excess lime pre-treatment step to remove the water hardness (determine the softening chemical addition rates [mass/hour] of Ca(OH)2 and Na2CO3) if the water chemistry is as follows [CO2] = 5 mg/l, [Ca2+] = 50 mg/L, [Mg2+] = 6.1 mg/L, [Na+] = 23 mg/L, [Alkalinity] = 150 mg/L and [SO42-] = 24 mg/L

In a general manner, explain how the rate of heat generation progresses during the formation of the concrete crystal matrix formed from cement paste molecules.  Be thorough in answering this question

Q1) Read the following sentences, write true or false, and correct the sentences that are false: 70, and by 20% 111 I Ultian vanas Ol Yu 3- The alkali silica reaction is very fast, happen between active silica in the cement and the alkalis in aggregate. Call wings: [5M] 4- Sulphate in mixing water should not be more than 10,000 ppm. 5- Higher curing temperature decrease earlier strength, but it increases 28-day strength of concrete.

Listen Concrete is required for the construction of an agricultural dairy barn floor slab in Central Alberta. The floor slab will be exposed to freeze/thaw conditions. Which of the following exposure classes best describes the environmental conditions that the concrete will be exposed to? A) A-2 B) A-4 OC) S-1 OD) S-2 APIO--:--) OLDG BO