Re: Temperature all'interno delle torri e comportamento dell'acciaio in generale
Inviato da fabriugo il 29/9/2013 22:26:45
In questi giorni sono stato un po' preso.
Ecco ciņ che mi aveva scritto nell'ultima mail, di ormai qualche giorno fa, Seffrin alla mia richiesta di spiegazione:
Although it looks very straightforward and simple, thermal imaging and accurate infrared temperature measurement are far more complicated than most people realize. While infrared energy behaves like daylight, there are several important differences that are not readily apparent to lay people.
First and foremost, thermal imagers cannot measure through most solid objects including glass and plastic that exceeding a few millimeters in thickness. Thermal imagers convert the normally invisible thermal patterns across the surface of an object into a color or monochrome image which is displayed on the monitor screen of the imager. Within a thermal image, the colors or gray shades represent the apparent thermal patterns across an object's surface. Thermal imagers that are capable of measuring temperature can also provide temperature values for imaged objects provided that the object is sufficiently close and the imager controls have been properly adjusted.
The thermal imager produced an image of thermal patterns across the surface of the buildings above and below the fires, in the breaches caused by the aircraft,
falling debris, and in small part, of the smoke that was produced by the fires. What is of particular interest in the thermal images is that the smoke which is visually opaque is largely transparent to the thermal imager. The ability for thermal imagers to image through visually opaque smoke is why firefighters use thermal imaging to assist them in their firefighting efforts.
The imager was properly calibrated and functioning correctly on September 11; however, the imager controls were not adjusted to afford accurate temperature measurement of the buildings at the World Trade Center. Even if the imager controls were properly set, the buildings were too far away to accurately measure their temperature. Since the temperature of fire is in excess of 120°C, it is an absolute certainty that the fires were burning hotter than the chosen temperature range on the thermal imager.
While post processing of thermal imaging is routinely done, it requires that the images are recorded to 12 bit media using a PC card or the imager's internal memory. In the case of the video, this media is only 8 bit and accurate post processing is not possible.
Although many people have expressed opinions as to the significance of our thermal images, most are incorrect. The thermal images taken on September 11 show the thermal patterns across the Towers 1 and 2 and provide qualitative information regarding the upper portions of the buildings which were visually obscured by smoke. They do not provide any information regarding the temperature of the buildings nor were they intended to. They simply are a unique record that was captured as interesting images without any expectation of future analysis or scrutiny and without any belief that the Towers would soon collapse.
Ecco ciņ che mi aveva scritto nell'ultima mail, di ormai qualche giorno fa, Seffrin alla mia richiesta di spiegazione:
Although it looks very straightforward and simple, thermal imaging and accurate infrared temperature measurement are far more complicated than most people realize. While infrared energy behaves like daylight, there are several important differences that are not readily apparent to lay people.
First and foremost, thermal imagers cannot measure through most solid objects including glass and plastic that exceeding a few millimeters in thickness. Thermal imagers convert the normally invisible thermal patterns across the surface of an object into a color or monochrome image which is displayed on the monitor screen of the imager. Within a thermal image, the colors or gray shades represent the apparent thermal patterns across an object's surface. Thermal imagers that are capable of measuring temperature can also provide temperature values for imaged objects provided that the object is sufficiently close and the imager controls have been properly adjusted.
The thermal imager produced an image of thermal patterns across the surface of the buildings above and below the fires, in the breaches caused by the aircraft,
falling debris, and in small part, of the smoke that was produced by the fires. What is of particular interest in the thermal images is that the smoke which is visually opaque is largely transparent to the thermal imager. The ability for thermal imagers to image through visually opaque smoke is why firefighters use thermal imaging to assist them in their firefighting efforts.
The imager was properly calibrated and functioning correctly on September 11; however, the imager controls were not adjusted to afford accurate temperature measurement of the buildings at the World Trade Center. Even if the imager controls were properly set, the buildings were too far away to accurately measure their temperature. Since the temperature of fire is in excess of 120°C, it is an absolute certainty that the fires were burning hotter than the chosen temperature range on the thermal imager.
While post processing of thermal imaging is routinely done, it requires that the images are recorded to 12 bit media using a PC card or the imager's internal memory. In the case of the video, this media is only 8 bit and accurate post processing is not possible.
Although many people have expressed opinions as to the significance of our thermal images, most are incorrect. The thermal images taken on September 11 show the thermal patterns across the Towers 1 and 2 and provide qualitative information regarding the upper portions of the buildings which were visually obscured by smoke. They do not provide any information regarding the temperature of the buildings nor were they intended to. They simply are a unique record that was captured as interesting images without any expectation of future analysis or scrutiny and without any belief that the Towers would soon collapse.
Messaggio orinale: https://old.luogocomune.net/site/newbb/viewtopic.php?forum=4&topic_id=7462&post_id=243532