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A piston-cylinder device contains 2 kg saturated water vapor at 600 kPa. The water expands adiabatically until the final pressure is 100kPa. And 1,465 kJ work is produced.
Suppose we want to estimate the average weight of adult males in greater metropolitan Atlanta area. We draw a random sample of 1,000 men from a population of 1,000,000 men and weigh them.
A cylindrical soil sample fails under an axial vertical stress of 160 kN/m^2, when it is laterally unconfined. The failure plane makes an angle of 50 degrees with the horizontal.
List the main sources of heat and humidity in mines and briefly describe the methods that can be used to control heat and humidity in an underground mining situation.
how large a sample must we take in order to be a) 95% b) 90% c) 99 d) 99.73% confident that the error in the estimated mean lifetime will not exceed 20 hours.
it is found that the lifetimes of television tubes manufactured by a company have a normal distribution with mean of 2000 hours and standard deviation of 60 hours. if 10 tubes are selected at random
Suppose that the acceleration of the train during the interval time from t=2 to t=4 s is a 2t m/s^2, and at t = 2 s its velocity is v = 180 km/hr. What is the train's velocity at t = 4 s
A horizontal Curve is designed for a two lane mountainous terrain. The following data are known. intersection angle: 40 degrees tangent length: 436.76 ft Station on PI: 2700+10.65 fs=0.12 e=0.08
Nitrogen expands in a friction-less piston-cylinder device from 0.10 to 0.30 m^3. The process is described by P= 7.4 - 40v + 60v^2 , where P is in bars and V is in cubic meters. Determine the work i
Determine the volume of three identical activated sludge tanks following primary clarification to aerate 36,000 m cubed/d with a BOD concentration of 180 mg/l at a BOD loading of 560 g/m cubed*d.
Determine the activated sludge aeration volume required to treat 2.64 mgd with a BOD of 120 mg/l based on the criteria of a maximum BOD loading of 40 lb/1000 ft cubed/day and a minimum aeration peri
Calculate the surface area required for a stabilization pond to serve a domestic population of 1000. Assume 80 gpcd at 210 mg/l of BOD. Use a design loading of 20 lb of BOD/acre/day.
Calculate the BOD loading and days of winter storage available between the 0.6 and 1.5 m depths, assuming a daily water loss of 0.30 cm by evaporation and seepage.
State the two main reasons why an activated sludge system is operated at a relatively low food/microorganism ratio.
Describe the various methods of methane drainage available to drain gas for longwall mining operations and methane drainage of longwall operations what factors influence the spacing of drainage boreh
Determine the dry/wet bulb temperatures of the mixed airstream and calculate the dry/wet bulb temperature assuming a pressure of 100 kPa and determine the effect on the radon daughter concentration.
Determine the cumulative exposure in WLM and determine the rate of emanation into the stope - working level of radon daughters at exit due to the initial radon
Determine the characteristic curves for the fan and define Kirchoffs first and second laws - determine the pressure to be developed by a single mine fan to ventilate the workings.
Based on your results, determine the after-tax income that you will need in order to afford the residence. Note that being qualified for a mortgage does not necessarily mean that one can actually "a
what is the pressure drop in each of the airways and the total pressure drop in the series combination of airways and what is the pressure drop in each of the airways and the total pressure drop in th
For the fully developed flow of water in a smooth 0.15-m pipe at a rate of 0:006m3/s, determine the thickness of a. the laminar sublayer; b. the buffer layer; c. the turbulent core.
In a three phase balanced system, a delta connected source supplies power to a wye connected load. If the line impedance is 0.2 + j0.4 ohms, the load impedance 3 + j2 ohms, and the source phase volt
Compare to units, A and B. A has a new cost of $42,000, at life expectancy of 14 years, a salvage value of $4,000, and an annual operating cost of $3,000. B has a new cost of $21,000, a life expecta
Calculate the airway resistance and the frictional pressure drop and determine the equivalent length for a sudden contraction in a mine airway from a cross-sectional area
You wish to retire at age 66 and at the end of each month thereafter for 30 years, to receive $5000. Assume that you begin making monthly payments into an account at age 24.