This model has been extended by Nigel Slack and his team in his operations management text.
Glass conducts heat poorly which limits the rate of heat transfer from the interior of the mirror to the outer surface. This also explains why the thickness of the mirror is more important 2 1 operation manegement the diameter or mass in determining how well the mirror will track the falling ambient temperature.
The path of the heat flow is predominantly from the center regions of the glass directly to the nearest outer surface. Fan Installation Schemes Rear-mounted cooling fans Adequate equilibrium can be reached with forced airflow over only the back of the mirror if it is thin enough.
The front surface temperature will track the falling air temperature closely enough even though most of the heat is being drawn out of the mirror's rear surface.
This is a fuzzy criteria, as it depends to some degree on where you live as described in the next section. Given how easy it is to install a rear-mounted fan on most scopes, they should be the first fan installed before attempting more challenging frontal fans.
Even in applications where a front-blowing fan is needed, you should still take advantage of cooling from the rear. Perhaps the simplest method for installing a rear fan is by suspending it behind the cell with elastic bands.
Attaching the fan to the mirror cell is a mistake! I prefer this method not only because it's simple, but also because it almost guarantees you won't have a vibration problem. With a quick connector in the wiring, it is easy to remove or reverse the fan in seconds. After playing with heavy rubber bands and metal springs, my current favorite elastic member is a hair band.
These are essentially miniature bungee cords, and are quite robust. I've yet to see one break like rubber bands sometimes will. When using a rear-mounted fan, you have a choice of airflow direction; blowing onto the back of the mirror, or sucking air out the bottom of the tube.
Unless the bottom of your tube is closed and carefully ducted, blowing the air stream at the mirror will be more efficient i. In practice, this slight advantage is almost meaningless, and other more pragmatic considerations take precedent.
If you regularly observe from a dry, dusty, location, consider pulling air out the bottom of the tube to reduce the accumulation of dirt on your optics.
Front-blowing fans For thicker primary mirrors, there is benefit to adding front-blowing fans along with the rear fans. Exactly how thick your mirror can be before needing front fans depends on where you live, as it is a function of how fast your nighttime temperatures usually fall see temperature profiles of cities.
In these cases, front-blowing fans are necessary to not only remove heat, but also to scramble the boundary layer. When using front fans for this purpose, you will need considerably more airflow across the front than what was recommended to just maximize heat loss. You are hereby warned that a vibration-free front fan installation is more difficult to implement than a rear fan.
Mounting fans directly to the tube of a solid tube style telescope is a sure way to induce microvibration in the image.Sri Lanka Flood Situation update hrs.
Heavy pre-monsoon rains in Sri Lanka from 20th to 26th May , have killed at least twenty-four people, and more than , people are affected in 20 District as of. Jul 03, · Hi MarvinP Thank you for the welcome! Your hit the nail on the head in your response, as this is a project, looking into improving the operation, optimizing the processes and finding the bottlenecks and shortages at the present situation.
Mark – as always, well done. Most confuse the concepts of project and process through interchangeability. But they are different. As such, a couple of terminology suggestions.
16 OCTOBER Civil Engineering OPERATIONS MANAGEMENT COMPLIANCE WITH THIS PUBLICATION IS MANDATORY management, and operations engineering. (T-1) Maintain capability to respond to and eliminate any facility or infrastructure .
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