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- Bin Abdul Rahim, H. R., et al.
(författare)
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Applied light-side coupling with optimized spiral-patterned zinc oxide nanorod coatings for multiple optical channel alcohol vapor sensing
- 2016
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Ingår i: Journal of Nanophotonics. - : SPIE - International Society for Optical Engineering. - 1934-2608. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- The width of spiral-patterned zinc oxide (ZnO) nanorod coatings on plastic optical fiber (POF) was optimized theoretically for light-side coupling and found to be 5 mm. Structured ZnO nanorods were grown on large core POFs for the purpose of alcohol vapor sensing. The aim of the spiral patterns was to enhance signal transmission by reduction of the effective ZnO growth area, thereby minimizing light leakage due to backscattering. The sensing mechanism utilized changes in the output signal due to adsorption of methanol, ethanol, and isopropanol vapors. Three spectral bands consisting of red (620 to 750 nm), green (495 to 570 nm), and blue (450 to 495 nm) were applied in measurements. The range of relative intensity modulation (RIM) was determined to be for concentrations between 25 to 300 ppm. Methanol presented the strongest response compared to ethanol and isopropanol in all three spectral channels. With regard to alcohol detection RIM by spectral band, the green channel demonstrated the highest RIM values followed by the blue and red channels, respectively.
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- Sterckx, S., et al.
(författare)
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SIMilarity Environment Correction (SIMEC) applied to MERIS data over inland and coastal waters
- 2015
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Ingår i: Remote Sensing of Environment. - : Elsevier BV. - 0034-4257 .- 1879-0704. ; 157, s. 96-110
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Tidskriftsartikel (refereegranskat)abstract
- The launch of several new satellites such as Sentinel-2, Sentinel-3, HyspIRI, EnMAP and PRISMA in the very near future, opens new perspectives for the inland and coastal water community. The monitoring of the water quality closer to the coast, within estuaries or small lakes with satellite data will become feasible. However for these inland and nearshore coastal waters, adjacency effects may hamper the correct retrieval of water quality parameters from remotely sensed imagery. Here, we present a sensor-generic adjacency pre-processing method, SIMilarity Environment Correction (SIMEC). The correction algorithm estimates the contribution of the background radiance based on the correspondence with the Near-INfrared (NIR) similarity spectrum. The performance of SIMEC was tested on MERIS FR images both above highly reflecting waters with high SPM loads, as well as dark lake waters with high CDOM absorption. The results show that SIMEC has a positive or neutral effect on the normalized remote sensing reflectance above optically-complex waters, retrieved with the MERIS MEGS or UR processor.
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| 4. |
- Yusof, H. H. M., et al.
(författare)
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Low-Cost Integrated Zinc Oxide Nanorods Based Humidity Sensors for Arduino Platform
- 2019
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Ingår i: IEEE Sensors Journal. - : IEEE. - 1530-437X. ; 9:7, s. 2442-2449
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Tidskriftsartikel (refereegranskat)abstract
- Realization of a simple integrated and low-cost intensity modulation/direct detection-based humidity and vapor detection system utilizing zinc oxide (ZnO) nanorods as the active material is demonstrated. The sensing device comprises of ZnO nanorods optimally grown on a glass substrate and mounted on 3D printed platform for the alignment with a green light-emitting diode setup for an edge excitation. An Arduino platform was used for the signal processing of the detection of the transmitted light. Both forward and backward scattering are affected due to light leakage while propagating through the glass substrate which are further attenuated in the presence of humidity. In this paper, backward scattering was found to be dominant, and thus, with increasing humidity, a reduction in the transmitted light was monitored. When the sensor was tested in a humidity controlled environment, it was found that the output voltage drops by approximately 750 mV upon changing the relative humidity (RH) level from 35% to 90% in a non-linear fashion. The average sensitivity of the sensor was observed to be-12 mV/% throughout the tested RH levels. Sensitivity was found to be higher at-24.6 mV/% for RH's beyond 70%. An average response time of 3.8 s was obtained for RH levels of 85% with respect to the standard ambient humidity conditions (RH 50%), which showed a quicker recovery time of 2.2 s. The proposed sensor device provides numerous advantages, including low-cost production, simplicity in design, ease of use, and stability during handling.
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