A water-based slurry of mineral is being filtered under vacuum, with a controlled pressure drop of 50 kPa, through a filter paper of 0.09 m² . The slurry is at 25 kg solids per m³ fluid. Use µ = 9.0 × 10−4 Pa.s and the following data:

V [L]                           t [s]                 

0.5                              19

1                                  41

2                                  95

3                                  178

4                                  280

Calculate the medium resistance, Rm; specific cake resistance, a; and the time to produce 5 liters of filtrate.

referring to the paper  "Recent insights on applications of pullulan in tissue engineering", authored by RS Singh, N Kaur, V Rana, and JF Kennedy. It was published in Carbohydrate Polymers, 2016, 153, 455-462.

Which are the physical traits of pullulan which recommend this polymer for tissue engineering ?

How injured tissues can be repaired with the help of artificially created polymeric scaffolds ?

Please mention few pullulan derivatives and explain why the derivatization was necessary for a particular type of application ?

Which are on your opinion the main challenges related to usage of pullulan in tissue engineering ?

A wet plastic film comprised of a polymer and acetone has to be dried using a hot stream of gas in a steady state process. The wet film contains 3 kg of a non-volatile polymer for every kg of acetone. Along with the input of the wet film, a second input of hot gas stream at 80°C is used for the drying process. Since the gas stream is obtained from a recovery unit, it contains nitrogen and a residual amount of acetone such that its relative saturation is 13%. The drying unit has to be evaluated for a case where 78% of acetone is removed from the wet film and the exit gas stream is at 46°C with a dew point temperature of 39°C.


Assume that only acetone transfers from the film to the gas phase i.e. it is the only condensable. Assume that all gas streams are at 1 atm. For vapor pressure of acetone, Antoine coefficients (A = 7.117, B = 1210.595, C = 229.664) in the textbook should be used and assumed to be valid at all given temperatures.


Solve the material balance and calculate the volume of input gas required per kg of the wet film as well as the relative and absolute saturation of the exit gas stream. Then choose the correct answer.

A sample of cross-linked natural rubber (polyisoprene) is found to have shear modulas G = 217 kPA at 20 C. Deduce N, the number of sub-chains between crosslinks per m^3 and hence the number average degree of polymerization between crosslinks. The chemical structure of polyisoprene. You may take for relative atomic mass C=12 and H=1, and for the density rho=909 kg/m^3. Assume <r^2>i = <r^2>o.

1.Write the complete molecular equation for the reaction of Zn(NO3)2 and KOH. Use the "\piπ" button to enter the equation using the equation format and be sure to include the appropriate states of matter.

2.Write the net ionic equation for the reaction in question 1. Use the "\pi π" button to enter the equation using the equation format and be sure to include the appropriate states of matter.

3.What are the spectator ions in for the reaction in question 1? Use the "\piπ" button to enter the equation using the equation format and be sure to include the appropriate charges on the ions.

4. The reaction in question 1 is run and the precipitate removed via filtration. The filtrate (solution which passes through the filter) is collected. We know that the spectator ions should be present, however, one of the active ions is probably limiting and the other active ion is in excess. How could you test for the presence of zinc(II) ions on the filtrate?

5.For the same experiment in the question above, how would you test for the presence of hydroxide ions in the filtrate? (Keep in mind that testing for pH is not a valid test in this case).

An incompressible liquid flows through a straight horizontal pipe. Friction of the fluid within the pipe causes a small amount of heat to be transferred from the fluid; to compensate, flow work must be done on the fluid to move it through the system (so W(dot)fl is greater than zero.

a) How are V(dot)in and V(dot)out related, where V(dot) is the volumetric flow rate of the liquid? (Remember, fluid is incompressible)

b) How must the pressures of Pin and Pout be related?

Any help is appreciated, I don't understand this at all.

Give 8 differences of Equilibrium (or flash distillation) and Simple batch (or differential distillation)

Describe the purpose and general makeup of a blowout preventer.

Consider the pair of reactions in which ethylene (C₂H₄) is oxidized either to ethylene oxide (C₂H₄O, desired) or to carbon dioxide (undesired).

(hint: assume 100 moles feed entering in reactor)

                                    C₂H₄ + ½ O₂   → C₂H₄O

                                    C₂H₄ + 3 O₂ → 2 CO₂ + 2 H₂O

The feed to the reactor contains 25% mole ethylene and 75% mole oxygen. The conversion of ethylene is 75% and the selectivity of ethylene oxide over carbon dioxide is 12.

a) determine ξ₁ and ξ₂ (18 mole, 0.75mole)

b) Calculate the molar composition (mole fractions) of the outlet stream. (0.069, 0.7, 0.198, 0.016, 0.016)

b) Calculate the fractional yield of ethylene oxide.(0.72)

When is a blowout said to occur? What are the consequences?

Why complete combustion reaction is good for automobiles and environment?

A liquid flows down an inclined plane surface in a steady, full developed laminar film of thickness h. Simplify the Navier-Stokes equations to model this flow field. Obtain expressions for the liquid velocity profile, the shear stress distribution, the volumetric flow rate, and the average velocity. Calculate the volumetric flow rate in a film of water h=1 mm thick, flowing on a surface b=1 m wide, inclined at 15 degrees to the horizontal.

describe the mechanisms by which pollutants are distributed and concentratedaround the globe in certain regions

. The reaction of 2O3(g) → 3O2(g) has the experimental rate: rate = k[O3]2 [O2]—1. The following mechanism has been proposed: 1. O3 O2 + O fast, equilibrium 2. O + O3 → 2 O2 slow (A) Identify any intermediates. (B) What is the rate law predicted by this mechanism? (C) Is the rate law predicted by the mechanism consistent with the experimental rate law? (D) How would adding a catalyst effect this reaction?