Compose a short essay on African History focusing on the impact the Saharan Desert had on the development of the continent.
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Why the temperature increase when flow rate of air increase in air-ch4 combustion, and equivalence ratio always uniforms ??
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A centrifugal pump delivers water at rate of 0.22 m3/s from a reservoir at a ground level to another reservoir to height 'h' through a vertical pipe of 0.2 m diameter. Both are open to atmosphere. Power input to pump is 90 kW and it operates with 75% efficiency . f=0.004 use g=9.8 m/s2 density=1000kg/m3. Find 'h'.
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When boiling water, a hot plate takes an average of 88 minutes [min] and 1515 seconds [s] to boil 170170 milliliters [mL] of water. Assume the temperature in the lab is 6969 degrees Fahrenheit. The hot plate is rated to provide 501501 watts [W]. If we wish to boil 170170 milliliters [mL] of acetone using this same hot plate, how long do we expect the process to take? Acetone has a boiling point of 5656 degrees Celsius. [Hint: you must determine the efficiency of the hotplate.]
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1.) What role, if any, do aquifers depletion overdrawing of surface waters, and salinization of irrigated soil play in the water problems associated with the High pLAINS AQUIFER AND THE COLORADO RIVER BASIN? How are these issues affected by drought and by development?
2.)Explain whether each of the following represents the point or nonpoint source pollution: fertilizer runoff, thermal pollution from a PowerPoint plant, urban runoff, sewage from a ship and erosion sediment from deforestations. Which is more difficult to control nonpoint source or point source pollution? Why?
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list the sequence of features that could form along a rocky, emergent coastline and describe how each feature is formed
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Recall that there are four fundamental forces: the gravitational force, the electromagnetic force, the weak nuclear force, and the strong nuclear force. Select any two of these forces and compare them. Consider their relative strengths, the range of distances over which they operate, and why they are important.
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Derive the kinetic equations (Michaelis-Menten equation) about 3 reversible inhibition kinetics: competitive inhibition, uncompetitive equation, and noncompetitive equation.
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What causes Transgression and Regression?
Transgression is the deepening water or an inland migration of coastline. Regression on the other hand in water becoming shallow or the seaward migration of the coastline. What causes this to happen? What accounts for the ordering of rocks along the shoreline?
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6. The volcanic mountains of the Cascades are composed primarily of andesite. Andesite is an intermediate igneous extrusive rock. Why are the Cascades volcanoes composed of andesite rather than basalt?
7. The article describes how the accretion of the Siletzia terrane around 60 million years ago “.. managed to bring everything to a grinding halt. It literally stopped the subduction and shut off the arc!” What does the author mean when she says “shut off the arc”?
9. Most of the fossils recovered in Washington State are not older
than about 55 million years. Why do we not find older fossils in
this region?
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A wastewater plant needs to reduce the methane content in water in a stripping tower to 0.3 mol %. The liquid stream is entering the tower with a flow rate of 200 mole/h and contains 0.8 mol % methane. The tower uses pure air for stripping and its temperature and pressure are held constant at 300 K and 1 atm, respectively. The equilibrium relation for methane in the air-water system is ? = 1.2?. a) Find the minimum vapor flow rate required to achieve this separation. B) Find the number of stages required if the vapor flow rate is taken as 1.2 ???? ′ .
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Solid particles (diameter 1.5 x 10-4 m, average density = 2800 kg/m3) are settling in water at 30 °C. The properties of water at this temperature are viscosity (µ) = 8 x 10-4 kg/m.s and density (p) = 996 kg/m3
a) What is the terminal velocity for the particles?
b) What would be the velocity of the system in a separator with an acceleration of 390 m/s2?
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1.
In what way is the Moon similar to the Earth?
Group of answer choices
takes the same time to rotate on its axis
similar atmosphere
same gravity on the surface
2
We believe the maria on the Earth's Moon are
Group of answer choices
ancient impact craters in which lava beds welled up from inside the Moon
giant volcanoes produced when the Moon tried to get plate tectonics going
large rifts filled with colder material made when the Moon's surface was cooling
3
What is the source of the fine, powdery dust found on the Moon's surface?
Group of answer choices
it is the result of volcanic activity on the Moon over billions of years
it is sand, produced in exactly the same way sand is produced on the Earth's beaches
it is the result of many impacts, breaking surface rocks apart over billions of years
4
Which of the following is a way that the planet Mercury is similar to the Moon?
Group of answer choices
the highest temperature on the two worlds is the same
it has a significant atmosphere
its surface is heavily cratered
5
The most likely models of the planet Mercury indicate that more than half the planet may be composed of
Group of answer choices
very light and porous rocks
metals
water
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A 2-shell passes and 4-tube passes heat exchanger is used to heat process stream from 35°C to 80°C by hot water available at 90°C, which enters the thin-walled 2.5-cm-diameter tube with total length of 65 m. The convection heat transfer coefficient is 76 W/m2 .°C on the process stream (shell) side and 190 W/m2 .°C on the water (tube) side. For a desired factor, FT = 0.95
a) Determine the rate of heat transfer in the heat exchanger.
b) Consider a fouling factor of 0.0012 m2 ·°C/W at the inner and outer surfaces of tube, determine the new rate of heat transfer
c) Evaluate the mass flow of hot water needed to compensate the heat loss due to fouling. Assume cp of hot water is 4.2 J/g.°C.
d) If the existing operating conditions are to be remained unchanged, evaluate the new area to compensate the heat loss due to fouling.
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