Answer:
A selective surface with large absorption for solar radiation and high reflectance for thermal infrared radiation was produced by use of surface oxidation of stainless steel. The surfaces were studied for use with concentrated light in a solar power plant at temperatures of 400°C and higher.
In order to investigate the relation between surface treatment and optical properties, stainless steels (AISI 304 and 430) which were submitted to different chemical and mechanical surface treatments, were used. To increase the spectral selectivity, these surfaces were treated in air and in vacuum at different temperatures and times. The optical properties of these films were investigated. Visual and infrared spectral absorptances were measured at room temperature. The thermal hemispherical emittance and absorptance were obtained by a calorimetric method at 200°C. It was noticed that these chemically and mechanically treated stainless steel surfaces have good spectral properties without further oxidations. This is very important for high temperature uses. The best values are found for samples 7 and 8 under vacuum and air. These two samples with mechanically ground surfaces retained their selectivity and specularity after several hours oxidation. One can conclude that the surface ground treatment confers good selectivity on the steel surfaces for use in concentrating solar collectors with a working temperature of 500°C.
Sample surfaces were subjected to long temperature ageing tests in order to gain some idea of the thermal stability of the surfaces. The results promise better-performing surface and the production of durable selective finishes at, possibly, lower cost than competing processes.
Explanation:
Answer:
Horitzontal and Vertical Lines
Explanation:
You can use this command to generate horizontal and vertical dimensions. Creating a linear dimension is easy. All you have to do is start the command, specify the two points between which you want the dimension to be drawn and pick a point to fix the position of the dimension line.
Answer:
a) The additional time required for the truck to stop is <u>8.5 seconds</u>
b) The additional distance traveled by the truck is <u>230.05 ft</u>
Explanation:
Since the acceleration is constant, the average speed is:
(final speed - initial speed) / 2 = 0.75 v0
Since travelling at this speed for 8.5 seconds causes the vehicle to travel 690 ft, we can solve for v0:
0.75v0 * 8.5 = 690
v0 = 108.24 ft/s
The speed after 8.5 seconds is: 108.24 / 2 = 54.12 ft/s
We can now use the following equation to solve for acceleration:
a = -6.367 m/s^2
Additional time taken to decelerate: 54.12/6.367 = 8.5 seconds
Total distance traveled:
0 - 108.24^2 = 2 * (-6.367) * s
solving for s we get total distance traveled = 920.05 ft
Additional Distance Traveled: 920.05 - 690 = 230.05 ft
The answer mostly likely is: “1” due to the fact it is well ordered, and follows a similar thought process, best of luck!
