Answer:
The distance from the entrance at which the boundary layers meet is 0.516m
The distance from the entrance at which the thermal boundary layers meet is 1.89m
Explanation:
For explanation, look at the attached file
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: B Excretory
Explanation: Hope this helps :)
Ability to recognize words and understand vocabulary
Answer: Option 2.
<u>Explanation:</u>
Reading comprehension is the capacity to process content, comprehend its significance, and to incorporate with what the peruser definitely knows. Capacity to grasp content is affected by perusers' aptitudes and their capacity to process data.
For the students reading comprehension problems frequently include troubles in perceiving and suitably applying foundation information, poor disentangling and word acknowledgment abilities, restricted jargon information, immature understanding familiarity, a not exactly key way to deal with cognizance.
