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Ferrocene molecular structure (a) and its view as a 3D model (b).  

Ferrocene molecular structure (a) and its view as a 3D model (b).  

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This work aims to investigate and characterize the photo-ignition phenomenon of MWCNT/ferrocene mixtures by using a continuous wave (CW) xenon (Xe) light source, in order to find the power ignition threshold by employing a different type of light source as was used in previous research (i.e., pulsed Xe lamp). The experimental photo-ignition tests w...

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... these works, the combustion ignition agent was constituted of the combination of metallic nanoparticles with CNTs mixed with different fuel mixtures (i.e., hexane/acetone, ethylene/air). On the other hand, ferrocene (FeCp 2 ), whose molecular structure is shown in Figure 1, was the first pure hydrocarbon derived from iron and was accidentally discovered in 1951 [16]. Starting from its discovery, many other chemical compounds derived from it were synthesized and utilized in different research areas. ...
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... both LP and SP filters it was possible to select a specific wavelength range (bandpass filter) of the Xe light source. By means of a laser power meter (model 407A, shown in Figure 10a), the luminous power emitted by the CW Xe lamp was measured by placing the sensor at the focal point where the MWCNT/ferrocene mixture is located (Figure 10b). ...
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... both LP and SP filters it was possible to select a specific wavelength range (bandpass filter) of the Xe light source. By means of a laser power meter (model 407A, shown in Figure 10a), the luminous power emitted by the CW Xe lamp was measured by placing the sensor at the focal point where the MWCNT/ferrocene mixture is located (Figure 10b). ...
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... the detector diameter is equal to 18 mm (with an area of 2.54 cm 2 ), the whole illumination area of the light beam (≈0.64 cm 2 ) falls within it (Figure 10b). ...
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... obtained results, reported in Figure 11, show that the 1:3 MWCNT/ferrocene mixture requires the least power to be ignited (240 mW which corresponds to a power density threshold of 377 mW/cm 2 ). An uncertainty of about ±4% was estimated, relative to the reported threshold light power values. ...
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... Figure 12, the luminous power thresholds obtained by employing SP filters (blue arrows) (each filter characterized by a UV cut-off frequency equal to about 380 nm) or LP filters (brown arrows) are reported. The measured power values related to the illumination area (0.636 cm 2 ) are highlighted in green, while the calculated luminous power density values (mW/cm 2 ) are shown in the brackets in orange. ...
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... measured power values related to the illumination area (0.636 cm 2 ) are highlighted in green, while the calculated luminous power density values (mW/cm 2 ) are shown in the brackets in orange. In Figure 13, the luminous power thresholds and calculated power density values relative to the combined use of SP and LP filters (i.e., band pass filters) are reported. The results highlight that in order to ignite the MWCNT/ferrocene mixture, less power in the range 210-240 mW (namely 330-377 mW/cm 2 ) is needed in the UV region. ...
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... results are consistent with the obtained absorption spectra (shown in Figure 3 and Figure 6). In fact, the absorption curves of ferrocene present a peak in the range 270-320 nm (however, this is not usable in the ignition tests of Figure 12 and Figure 13 because of the SP filter absorption in UV region) and a less intense but wider peak around 440 nm. Moreover, a higher absorption has been found for MWCNT/ferrocene mixtures illuminated by visible radiation with decreasing the wavelength up to 400 nm. ...
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... results are consistent with the obtained absorption spectra (shown in Figure 3 and Figure 6). In fact, the absorption curves of ferrocene present a peak in the range 270-320 nm (however, this is not usable in the ignition tests of Figure 12 and Figure 13 because of the SP filter absorption in UV region) and a less intense but wider peak around 440 nm. Moreover, a higher absorption has been found for MWCNT/ferrocene mixtures illuminated by visible radiation with decreasing the wavelength up to 400 nm. ...
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... a higher absorption has been found for MWCNT/ferrocene mixtures illuminated by visible radiation with decreasing the wavelength up to 400 nm. In Figure 14, some frames are shown extrapolated from videos recorded during the ignition tests. ...
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... the following pictures reported in Figure 15, the time evolution of the combustion process is shown when using the full spectrum of the Xe-lamp light beam, i.e., without any selective filters. The combustion flame is clearly visible (after only 100 ms, third frame) and it occurs for the 1:3 MWCNT/ferrocene mixture weight ratio, with a luminous power density equal or higher than 377 mW/cm 2 . ...
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... combustion flame is clearly visible (after only 100 ms, third frame) and it occurs for the 1:3 MWCNT/ferrocene mixture weight ratio, with a luminous power density equal or higher than 377 mW/cm 2 . In Figure 16, the images of MWCNT/ferrocene samples before and after the ignition process are shown. As reported in the literature, after ignition, the exposed samples display orange dots or clusters because of the presence of ferrocene in the mixture (more evident with increasing ferrocene concentration), indicative of iron oxide particles [9,15]. ...
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... depending on the selected wavelength range of the incident Xe light used to trigger the photo-induced ignition process. From a chemico-physical point of view, the suggested evolution of ignition process has been summarized in the Figure 17. ...
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... reported in Figure 17, the photo-induced process of charge separation, promoted by UV-vis-IR light irradiation (photon energy h•ν = h•c/λ with 380 nm < λ < 1000 nm, c speed of light and h Planck constant), represents the key step of the MWCNT/Fe ignition process. In this scenario, as already widely reported in the literature, the presence of metal nanoparticles (in this work FeCp 2 ) allows for the photo-ignited reaction. ...
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... easily react with oxygen (O 2 ) giving rise to a typical combustion reaction. Of course, the opportune combination of the proper incident light wavelength range and luminous power (as reported in Figure 12 and Figure 13) are important in order to ensure the success of the MWCNT/ferrocene ignition process. ...
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... easily react with oxygen (O 2 ) giving rise to a typical combustion reaction. Of course, the opportune combination of the proper incident light wavelength range and luminous power (as reported in Figure 12 and Figure 13) are important in order to ensure the success of the MWCNT/ferrocene ignition process. ...
Context 17
... these works, the combustion ignition agent was constituted of the combination of metallic nanoparticles with CNTs mixed with different fuel mixtures (i.e., hexane/acetone, ethylene/air). On the other hand, ferrocene (FeCp 2 ), whose molecular structure is shown in Figure 1, was the first pure hydrocarbon derived from iron and was accidentally discovered in 1951 [16]. Starting from its discovery, many other chemical compounds derived from it were synthesized and utilized in different research areas. ...
Context 18
... both LP and SP filters it was possible to select a specific wavelength range (bandpass filter) of the Xe light source. By means of a laser power meter (model 407A, shown in Figure 10a), the luminous power emitted by the CW Xe lamp was measured by placing the sensor at the focal point where the MWCNT/ferro- cene mixture is located (Figure 10b). ...
Context 19
... both LP and SP filters it was possible to select a specific wavelength range (bandpass filter) of the Xe light source. By means of a laser power meter (model 407A, shown in Figure 10a), the luminous power emitted by the CW Xe lamp was measured by placing the sensor at the focal point where the MWCNT/ferro- cene mixture is located (Figure 10b). ...
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... the detector diameter is equal to 18 mm (with an area of 2.54 cm 2 ), the whole illumination area of the light beam (≈0.64 cm 2 ) falls within it (Figure 10b). ...
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... obtained results, reported in Figure 11, show that the 1:3 MWCNT/ferrocene mixture requires the least power to be ignited (240 mW which corresponds to a power density threshold of 377 mW/cm 2 ). An uncertainty of about ±4% was estimated, relative to the reported threshold light power values. ...
Context 22
... Figure 12, the luminous power thresholds obtained by em- ploying SP filters (blue arrows) (each filter characterized by a UV cut-off frequency equal to about 380 nm) or LP filters (brown arrows) are reported. The measured power values related to the illumination area (0.636 cm 2 ) are highlighted in green, while the calculated luminous power density values (mW/cm 2 ) are shown in the brackets in orange. ...
Context 23
... measured power values related to the illumination area (0.636 cm 2 ) are highlighted in green, while the calculated luminous power density values (mW/cm 2 ) are shown in the brackets in orange. In Figure 13, the luminous power thresholds and calculated power density values relative to the combined use of SP and LP filters (i.e., band pass filters) are reported. The results highlight that in order to ignite the MWCNT/ferrocene mixture, less power in the range 210-240 mW (namely 330-377 mW/cm 2 ) is needed in the UV region. ...
Context 24
... results are consistent with the obtained absorption spec- tra (shown in Figure 3 and Figure 6). In fact, the absorption curves of ferrocene present a peak in the range 270-320 nm (however, this is not usable in the ignition tests of Figure 12 and Figure 13 because of the SP filter absorption in UV region) and a less intense but wider peak around 440 nm. Moreover, a higher absorption has been found for MWCNT/ferrocene mix- tures illuminated by visible radiation with decreasing the wavelength up to 400 nm. ...
Context 25
... results are consistent with the obtained absorption spec- tra (shown in Figure 3 and Figure 6). In fact, the absorption curves of ferrocene present a peak in the range 270-320 nm (however, this is not usable in the ignition tests of Figure 12 and Figure 13 because of the SP filter absorption in UV region) and a less intense but wider peak around 440 nm. Moreover, a higher absorption has been found for MWCNT/ferrocene mix- tures illuminated by visible radiation with decreasing the wavelength up to 400 nm. ...
Context 26
... a higher absorption has been found for MWCNT/ferrocene mix- tures illuminated by visible radiation with decreasing the wavelength up to 400 nm. In Figure 14, some frames are shown extrapolated from videos recorded during the ignition tests. ...
Context 27
... the following pictures reported in Figure 15, the time evolution of the combustion process is shown when using the full spectrum of the Xe-lamp light beam, i.e., without any selective filters. The combustion flame is clearly visible (after only 100 ms, third frame) and it occurs for the 1:3 MWCNT/ferrocene mixture weight ratio, with a luminous power density equal or higher than 377 mW/cm 2 . ...
Context 28
... combustion flame is clearly visible (after only 100 ms, third frame) and it occurs for the 1:3 MWCNT/ferrocene mixture weight ratio, with a luminous power density equal or higher than 377 mW/cm 2 . In Figure 16, the images of MWCNT/ferrocene samples before and after the ignition process are shown. As reported in the lit- erature, after ignition, the exposed samples display orange dots or clusters because of the presence of ferrocene in the mixture (more evident with increasing ferrocene concentration), indica- tive of iron oxide particles [9,15]. ...
Context 29
... depending on the selected wavelength range of the incident Xe light used to trigger the photo-induced ignition process. From a chemico-physical point of view, the suggested evolution of ignition process has been summarized in the Figure 17. ...
Context 30
... reported in Figure 17, the photo-induced process of charge separation, promoted by UV-vis-IR light irradiation (photon energy h•ν = h•c/λ with 380 nm < λ < 1000 nm, c speed of light and h Planck constant), represents the key step of the MWCNT/Fe ignition process. In this scenario, as already widely reported in the literature, the presence of metal nanopar- ticles (in this work FeCp 2 ) allows for the photo-ignited reaction. ...
Context 31
... easily react with oxygen (O 2 ) giving rise to a typical combustion reaction. Of course, the opportune combination of the proper incident light wavelength range and luminous power (as reported in Figure 12 and Figure 13) are important in order to ensure the success of the MWCNT/ferrocene ignition process. ...
Context 32
... easily react with oxygen (O 2 ) giving rise to a typical combustion reaction. Of course, the opportune combination of the proper incident light wavelength range and luminous power (as reported in Figure 12 and Figure 13) are important in order to ensure the success of the MWCNT/ferrocene ignition process. ...

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