A chemostat is a continuous stirred tank bioreactor that can carry out fermentation of a plant cell culture. Its dynamic behavior can be described by the following model:̇ X=μ(S)X−DẊ                                       S=−μ(S)X∕YX∕S+D(Sf−S)X and S are the cell and substrate concentrations, respectively,and Sf is the substrate feed concentration. The dilution rate D is defined as the feed flow rate divided by the bioreactor volume.D is the input, while the cell concentration X and sub-strate concentration S are the output variables. Typically, the rate of reaction is referred to as the specific growth rate μ and is modeled by a Monod equation,   μ(S)=μmS/(Ks+S) Assume μm=0.20 h−1,Ks=1.0 g/L, and YX/S=0.5 g/g. Usea steady-state operating point of D=0.1h-1,  X=4.5g∕L,S=1.0g∕L, and Sf=10 g∕L.Using linearization, derive a transfer function relating thedeviation variables for the cell concentration(X−X)to the dilution ration(D−D).

Liza is a chemical engineer working for a wastewater treatment facility. One of thebyproducts of sewage treatment is sludge. After microorganisms, grow in the activatedsludge process to remove nutrients and organic material, a substantial amount of wet sludge is produced. This sludge needs to be dewatered, one of the most expensive parts of mosttreatment plant operations. Liza suggests that the sludge be dried and sold as fertilizer. She also mentions that burning the sludge as fuel is also effective. To burn this, fuel oil is mixed with it, and the mixture is burned in a furnace with air. Her boss agrees with burning but further data is needed in order to proceed with the plan. Since additional cost is required for the fuel oil, Liza needs to determine if burning is worth it. The data below shows the analysis for the sludge and the combustion products Sludge (%)    Combustion Products (%) S   -  32                  SO2 - 1.52C   - 40                   CO2 - 10.14H2 - 4…

Problem 1 The dehydrogenation of a compound (elementary kinetics) is taking place in a selective membrane reactor under isothermal conditions. A B+ ½ C The reaction is reversible and Kc is the equilibrium constant. The manner in which Kc ( the mass transfer coefficient at volumetric flow rate vo) increases with flow rate depends upon the flow geometry and the mass transfer dependence on velocity is given by KC = kco (v/v) 1/2 And the membrane transport of C is given by keaCc when permeate concentration of C is low. The following parameter values apply, k = 0.5 dm³/ kg.min, vo = 50 dm³/min, Kc = 0.5 (kg-mol/dm³) ½ Po 10 atm, FA0= 10 kg-mol/min; a = 0.002 atm/kg Kco 0.1 dm/min W = 200 kg 1. Compare the calculated output valued of FB, the molar flow rate of B for no pressure drop.

An evaporation-crystallization process (as shown below) is used to obtain solid potassium sulfate from an aqueous salt solution. The feed contains 18.7 wt% K2SO4. The wet filter cake contains solid sulfate crystals and a 40.0 wt% salt solution. The filtrate is recycled to mix with the feed. The evaporator has a capacity of 175 kg of water evaporated per second. The filtrate has 40.0 wt% salt solution, as well, and from the water entering the evaporator, 45.0% is evaporated. In the wet filter cake, there is 10 kg of the solid crystals for every 1 kg of the salt solution. a.) Calculate the fresh feed rate. (Include units) b.) Determine the production rate of crystal. (Include units) c.) Calculate the recycle ratio. (kg recycle/kg feed) Include units

You are working on determining the Oxygen Transfer Rate (OTR) and Oxygen Uptake Rate (OUR) in a bioreactor.  You perform two set of experiments in a 3L bioreactor.  During the first set of experiments, you fill the bioreactor with water only, you remove all the dissolved oxygen and start sparging it with air at the specified agitation speeds and air flowrate.  Which of the following methods could be used to estimate the volumetric oxygen transfer coefficient (kLa)? C*: saturation concentration of dissolved Oxygen  CL: concentration of dissolved Oxygen at any given time   Question options:   kLa  is the slope of a ln(C* ) versus time plot   kLa  is the slope of a CL versus time plot   -kLa  is the slope of a ln(C* - CL) versus time plot   kLa  is the slope of a ln(C* - CL) versus time plot

Please help with homework problem.

Aurorae Borealis, or northern lights, are natural light displays observed around the arctic region. They are caused by the interaction of charged particles emitted in solar flares with gases in the higher strata of the atmosphere. In the process, the energy from the charged particles is transferred to the gas molecules, giving rise to the emission of light. a. Describe the mechanism by which light is emitted as a result of this interaction.