Q2. What type of plastics are used in household garbage?
The plastic fraction in household garbage mainly consists of 5 plastic types, which are polyethylene (PE), polyethyleneterephthalate (PET), polypropylene (PP), polystyrene (PS) and polyvinylchloride (PVC).
Q3. What is the important result of the experiment?
The most important result was that high SNR spectra from 824 to 1700 nm can provide information sufficient for plastic identification.
Q4. What are the main advantages of using NIR spectroscopy to identify plastics?
Mass spectroscopy, X-ray fluorescence, plasma spectroscopy and vibrational spectroscopy (NIR-, MIR- or Raman-spectroscopy) have been applied by different groups [ 11.
Q5. What was the aim of the experiment?
The aim of the described experiment was to test if a suited spectrometer concept can combine the industrial requirements of robustness and speed with the need of recording high quality spectra from plastics without direct contact between sample and coupling optics,
Q6. What is the size of the plastic samples?
The plastic samples, that are cut out of plastic bodies taken from municipal waste, have a size of some cm* and thicknesses from 0.5 toseveral mm.
Q7. How many spectra can be obtained from plastics?
It has been demonstrated that NIR spectra from 824 to 1700 nm of plastics with high signal to noise ratio can be obtained from a distance of up to 50 cm within 6.3 milliseconds.
Q8. What is the name of the experiment?
All rights reserved SSDZ 0022-2860(95)08609-9result, Inc53Gac,47As with a spectral range from 800 to 1700 nm and sensitivity reaching D*- 1013 cm Hzl%V at room temperature [8] can be used as detector material.
Q9. How long does it take to read out the spectrometer?
Control and read-out of the room-temperature operated detector is realised with a combination of a micro processor controller and a personal computer, allowing of a minimum integration time of 6.3 ms.
Q10. What is the SNR of the spectrometer?
The described set-up gives a SNR of at least 200: 1 even in outer regions of the spectrum where the detector sensitivity decreases (at 824 or 1700 nm respectively).
Q11. What is the spectral range of the spectra of the plastic?
Spectral ranges from 1000 to 1800 nm [2,3] or from 1000 to 2500 nm [5] have been accessed with Ge or PbSe detectors respectively.
Q12. What is the significance of the concept of a PCA?
The authors expect that this concept will provide the means for on-line identification of plastic garbage at usual speeds of industrial conveyor belts of up to 2 m/s.
Q13. How many complete identification cycles can be performed per second?
Taking also into account the computation time of a neural network based decision algorithm as developed by Wienke et al. [9], 75 complete identification cycles can be performed per second.
Q14. What is the role of recycling plastics in the society?
The recycling of plastics plays an increasingly important role in today’s society and large efforts are undertaken to find new ways to reuse post-consumer plastics.