A small city is situated on the countryside. Upstream form the city is a dam that provides the city's water supply. If the dam was overtopped by water, then the dam would fail and all of the water would flood through the city. There is also a danger that the dam might collapse when it is full of water and cause it to fail, also flooding the city.

A) Draw a fault tree for the head event “Dam fails and floods the town” using the following basic events The possibility of dam collapse is (P=0.01)

There is a weakness in the dam that would allow collapse to cause the dam to fail (P=0.1).

Storm occurs that overtops the dam provided that it is mostly full (P=0.002)

Storm occurs that will overtop the dam no matter how full the dam is (P=0.0004)

Dam is mostly full (P=0.4).

B) Determine the probability that the dam will fail and flood the town. For the hours of daylight (assume 12 hours on average) there is someone working at the dam who could send a warning to the city if the dam failed.

There is an 80% probability that this person would be able to get the message to the city in time to evacuate. If the dam failed during the night no one would see it, but there is a 60% chance that the weather conditions would be such that the noise of the dam breaking could be heard by someone in the city and give them enough warning to evacuate everybody.

However, every Saturday night the city has a large party, and nobody would be able to hear if the dam failed anyway.

C) Draw an event tree that can be used to determine the conditional probability that the city will receive warning in time to evacuate.

D) Determine this conditional probability of receiving the warning on time.

E) What is the overall probability that the town will be flooded without an evacuation occurring? Hint: consider your answer for (b).

Why is precise stability analysis of slopes difficult to predict?

What is the difference between the Stability Number method and the Method of Slices?

A strip footing 2.5 m wide is loaded on the ground surface with a pressure equal to 175 kPa. Calculate the stress distribution at depths of 2.5, 7.5 and 12.5 m under the center of the footing. If the footing rested on a normally consolidated cohesive layer whose Cc was 0.612 and whose e0 was 1.35 , estimate the settlement of the footing. Assume S = 100%,γ’ = 7.5 kN/m3 , and the total clay layer thickness beneath the footing = 15 m.

Explain how the use of a shear key below a retaining wall foundation would provide resistance against sliding. How would you as a designer account and quantify the resistance developed by the use of a shear key? Finally, why is the contribution of the shear key so significant for such a small addition?

1. The following data are obtained from the current meter gauging of a stream, at a gauging station. Compute the stream discharge using mean section method.

Rating equation of current meter: v = 0.2 N + 0.04, where N = rev./sec, v = velocity (m/sec).                                                                              

The following are average operating data from a secondary activated sludge:

Wastewater flow = 29160 m3/d

Vol. of aeration tanks = 8400 m3

Influent SS = 120 mg/L Influent BOD5 = 170 mg/L

Effluent SS = 22 mg/L Effluent BOD5 = 20 mg/L

Volatile fraction of mixed liquor and effluent suspended solids is 0.65.

Mixed liquor suspended solids = 2500 mg/L

Waste sludge flow = 200 m3/d SS in Waste sludge = 9800 mg/L

Determine the following:

Aeration period, Food to micro-organisms in kg BOD/kg MLVSS /d, Volumetric BOD Loading ,Sludge age ,Observed yield in gVSS/g BOD5 ,True yield in gVSS/g BOD5 assuming a kd of 0.05 d-1 ,Daily oxygen demand

Please determine the dimensions and air flowrate required for a 3m deep aerated grit chamber designed to remove 70% of 0.02 cm diameter sand [specific gravity = 2.65] at 20ºC. Assume that only particles of 0.001 cm will be scoured away. The wastewater flow rate is 10000 m3/d. Use a b of 0.04 and f of 0.03 for calculations.

Consider   a   vapour   compression   refrigeration   cycle   that   uses   R-134a   as   refrigerant.   The   R-134a   enters   the   compressor   as   a   saturated   vapour   at   200   kPa,   and   exits   the   condenser   as   a   saturated   liquid   at   900   kPa.   The   rate   of   refrigeration   of   the   cycle   is   to   be   6.0   tons   of   refrigeration   (1   ton   of   refrigeration   =   3.517   kW).   The   compressor   isentropic   efficiency   is   80%.   Determine:   a) The   temperature   of   evaporation   and   condensation   of   the   refrigerant;   b) Mass   flow   of   the   refrigerant   R-134a,   in   kg/min;   c) Coefficient   of   Performance   (COP)   of   the   refrigeration   cycle.   Typical   vapour   compression   refrigeration   systems   use   a   throttling   valve   (or   an   orifice   tube,   or   a   capillary   tube)   to   reduce   the   liquid   refrigerant’s   pressure.   This   is   a   highly   irreversible   process.   If   the   cycle   efficiency   is   to   be   improved   by   replacing   the   throttle   with   a   rotary   expander   with   70%   isentropic   efficiency,       d) What   is   the   new   COP?   The   expander   delivers   its   work   developed   to   the   compressor.  
  

• Plan and write a 4-or 5-paragraph problem/solution essay, including
• A clear outline with emphasis on a focused and specific thesis statement and a topic sentence for each paragraph
• Describe a problem and suggest 2 solutions (in 2 paragraphs) to overcome it
• it is an assignment for general English It is better if the subject is outside of engineering. I asked for help in the wrong field because I want to get the full degree and I have a study for the test and I do not have time to do it myself

A field test is conducted in a confined aquifer by pumping a constant discharge of 14.9 m³/hr from 20-cm-diameter well. After an approximate steady state is reached, a drawdown of 0.98 m is measured in the pumped well. Also measured are drawdowns of 0.73 m, 0.65 m, 0.60 m, and0.57 m, respectively, at 8.0 m, 30.0 m, 80.0 m, and 132 m from the pumped well. Determine the transmissivity of this aquifer. Also, determine how far away from the well you must be before the drawdown becomes less than 0.45 m.

Explain, with reasons, whether you can use the following tests to simulate the behavior of sand in liquefaction

i) Unconsolidated Undrained Triaxial Test

ii) Direct Shear Test

iii) What is the most suitable type of triaxial test that should be used? (Does not have to be (i) or (ii))

QUESTIONS:

Design a square column footing for a 20-in. square tied interior column that supports loads of DL (170) k and Live load LL (210) k. The column is reinforced with eight No 8 bars, the bottom of the footing is 5 foot below final grade, and the soil weighs 100 lb. /ft3 the allowable soil pressure is 4 w ksf. The concrete strength is 4,000 psi and the steel is Grade 60.

Environmental lapse rate = 0.1 degree C/100m upto 100 m altitude (surface temperature drop at nighttime).

Environmental lapse rate = -0.7 degree C/100m after 100 m altitude

The adiabatic lapse rate is based on moist air.

Find the atmospheric condition from the example below.

a) Mixed radiational inversion

b) Radiational inversion

c) Subsidentail inversion

d) Frontal inversion

e) Advective inversion

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A Class I two-lane highway is on level terrain with passing permitted throughout. The highway has 3.6 m lanes with 1.1 m shoulders. There are 13 access points per kilometer. The base FFS is 96.5 km/hr. During the peak hour, 500 vehicles are traveling in the analysis direction and 400 vehicles are traveling in the opposing direction. If the PHF is 0.8 and there are 7% large trucks, 7% buses, and 7% recreational vehicles, what is the level of service?

The rate of change of the grade of a parabolic summit curve is 0.5%. The grade of ascending and descending tangents are 6% and -2.0% respectively. The elevation of VPT is 200 ft at Sta 15+80. Determine the:

a) length of curve;

b) elevation of the summit,

c) location of the summit;

d) the vertical distance from VPI to the curve;

e) elevation at Sta 06+80.