Astigmatism is due to too flat a cornea
Indicate whether the statement is true or false
F
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Solar One, located near Barstow, CA, was the first large-scale (10 MW electric) solar- thermal electric-power-generating plant in the United States. A schematic diagram of the plant is shown below. The receiver may be treated as a cylinder 7 m in diameter and 13.5-m-tall. At the design operating conditions, the average outer surface temperature of the receiver is about 675°C and ambient air temperature is about 40°C. Estimate the rate of heat loss, in MW, from the receiver—via natural convection only—for the temperatures given. What are other mechanisms by which heat may be lost from the receiver?
GIVEN
• A vertical cylinder in air
• Height of cylinder (L) = 13.5 m
• Diameter (D) = 7 m
• Surface temperature (Ts) = 675°C
• Ambient air temperature (T?) = 40°C
FIND
(a) The rate of convective heat loss (qc) in MW
(b) What other mechanisms for heat loss exist?
ASSUMPTIONS
• Air is still
• Surface temperature is uniform and constant
PROPERTIES AND CONSTANTS
for dry air at the mean temperature of 357.5°C
Thermal expansion coefficient (?) = 0.00160 1/K
Thermal conductivity (k) = 0.0461 W/(m K)
Kinematic viscosity (?) = 58.1 × 10–6 m2/s
Prandtl number (Pr) = 0.72
The Moon's average distance from Earth is about ______________ km
Fill in the blank(s) with correct word
An archaeologist finds the 14C in a sample of 3.10 g of material to be decaying at 107 counts per second. A modern 1.00-g sample of the same material decays at 151 counts per second. The half-life of 14C is 5730 y. How old is the sample?
A) 12,200 y B) 8460 y C) 25,100 y D) 12,600 y
The diagram below shows three approximate locations of the sun along the western horizon. Which number indicates the location of the sun at sunset on December 21st for an observer at latitude 48° N?
a. 1
b. 2
c. 3
d.The sun will set in the east.
e.The sun will not set on December 21st at this latitude.