Question 68 – Biochemical Oxygen Demand (BOD) could be calculated using the formula BOD = (DOi - DOf) (Vb / Vs) where Vb = Volume of bottle in ml, Vs = Volume of sample in ml, DOi = Initial dissolved oxygen in mg / L, DOf = Final dissolved oxygen in mg / L. (a) By using a bottle of Vb = 300 ml with sample Vs = 30 ml, find the BOD if DOi = 8.8 mg / L and DOf = 5.9 mg / L. (b) By using a bottle Vb = 600 mL with sample Vs = 100 mL, find the BOD if DOi = 8.8 mg / L and DOf = 4.2 mg / L. (c) Find the average BOD = [ Answer of (a) Answer of (b) ] / 2. (d) If the BOD-5 test for (a) - (c) is run on a secondary effluent using a nitrification inhibitor, find the nitrogenous BOD (NBOD) = TBOD - CBOD. Let TBOD = 45 mg / L and CBOD = Answer of (c).

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Question 86 - (a) Male with genotype GGmm and phenotype gray wingless mates with female with genotype ggMM and phenotype black winged in fruit flies. G is dominant to g in color. M is dominant to m in wing shape. If the actual distribution of the second generation of the fruit flies was as follow : 890 gray wingless, 900 black winged, 115 gray winged, 95 black wingless, calculate the recombination frequency betwen the two genes and distance in recombination units. Let 1 map unit = 1 % recombination. (b) A DNA molecule has 180 base pairs and 20 % adenine. How many cytosine nucleotides are present in this molecule of DNA?

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which reformer efficiencywise best?

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Question 55 - The differential equation is 3 dy / dt + 2y = 1 with y(0) = 1. (a) The Laplace transformation, L for given terms are : L (dy / dt) = sY(s) - y(0), L(y) = Y(s), L(1) = 1 / s. Use such transformation to find Y(s). (b) The initial value theorem states that : When t approaches 0 for a function of y(t), it is equal to a function of sY(s) when s approaches infinity. Use the initial value theorem as a check to the answer found in part (a).

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hello everyone do anyone have interview questions for any chemical industry please email me at

0 Answers   ONGC,

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What is a barometric condenser?

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What is a solvent?

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how much maximum power can be generated by 320v, 10kg-cm synchronus motor if shaft is roteted mechanically at 50 to 60 rpm?

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Why LMTD is calculated in Heat -Exchanger problems..Why dont we take average temperature??

4 Answers   Aker Solutions,

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What is the iodine value of spent carbon?How iodine value is used to determine the power of carbon to adsorb?

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Define wet bulb globe temperature?

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X is strong but has a very low density (1% of traditional earth materials.) and hence light weight. It is a recyclable material. The compression behaviour of X is strain rate dependent. Higher strain rates result in higher initial modulus and higher compression strength. It can also withstand unlimited number of cycling loading provided the repetitive loads are kept below 80% of the compressive strength. The internal structure of the material includes air-traps which make it poor heat conductor. X is non- biodegradable and chemically inert in both soil and water. Most acids and their water solutions do not attack it; however strong oxidizing acids do. Solvents which attack X include esters, ketones, ethers, aromatic and aliphatic hydrocarbons and their emulsions, among others. It does not support bacterial/fungal growth as well .It also has significant acoustic properties and effectively reduces the transmission of airborne sound. X is combustible and should not be exposed to open flame or other ignition sources. Combustion products are carbon monoxide, carbon dioxide, water and soot. Long-term exposure to sunlight causes yellowing and a slight embrittlement of the surface due to ultraviolet light. X is able to withstand the rigours of temperature cycling, assuring long-term performance.

0 Answers   Ford,

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