Answer:
c) It takes a greater hydraulic head to drive the groundwater laterally to the well casing in the lower permeability aquifer
Explanation:
The groundwater are contains under the rock and in the open spaces within the rocks and the unconsolidated sediments. Aquifer refers to the underground layers of the permeable sand or rocks that transmits the groundwater below water table which provides a sufficient supply of water to the well. Groundwater is present everywhere where there is porosity in the rocks and it depends on the permeability of the rocks to allow them flow.
A drawdown cone is completed in the lower permeable aquifer deeper and narrower than the high permeable aquifer as it takes more amount hydraulic head or energy to drive groundwater to the well casing which is in the lower permeable aquifer.
Known :
V1 = 10 L
T1 = 27°C
P1 = 12 atm
P2 = 3 atm
Solution :
Work done in the process
W = P1 • V1 ln (P1 / P2)
W = (12 atm) • (10 L) ln (12 / 3)
W = 166.35 L • atm
W = 168.55 kJ
Answer:
The electrical work for the process is 256.54 Btu.
Explanation:
From the ideal gas equation:
n = PV/RT
n is the number of moles of air in the tank
P is initial pressure of air = 50 lbf/in^2 = 50 lbf/in^2 × 4.4482 N/1 lbf × (1 in/0.0254m)^2 = 344736.2 N/m^2
V is volume of the tank = 40 ft^3 = 40 ft^3 × (1 m/3.2808 ft)^3 = 1.133 m^3
T is initial temperature of air = 120 °F = (120-32)/1.8 + 273 = 321.9 K
R is gas constant = 8.314 J/mol.k
n = 344736.2×1.133/8.314×321.9 = 145.94 mol
The thermodynamic process is an isothermal process because the temperature is kept constant.
W = nRTln(P1/P2) = 145.94×8.314×321.9×ln(50/25) = 145.94×8.314×321.9×0.693 = 270669 J = 270669 J × 1 Btu/1055.06 J = 256.54 Btu
The following is a feedback mechanism for a system :
<u>The progress bar when downloading a file on iTunes</u>
<u></u>
Explanation:
- A feedback mechanism is a loop system wherein the system responds to a perturbation. The response may be in the same direction (as in positive feedback) or in the opposite direction (as in negative feedback).
- Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to feed back into itself.
- Evaluation feedback needs to be done “in the moment” to help the person receiving the feedback know where they stand.
- A feedback control system consists of five basic components: (1) input, (2) process being controlled, (3) output, (4) sensing elements, and (5) controller and actuating devices.
- Because negative feedback produces stable circuit responses, improves stability and increases the operating bandwidth of a given system, the majority of all control and feedback systems is degenerative reducing the effects of the gain.
