Field analysis Cr(VI) in water samples by a smartphone-based ultralong absorption path reflection colorimetric device

Hexavalent chromium is highly toxic and regarded as one of the main pollutants in environmental samples. Sophisticated laboratory instruments are commercially available for in-field determination of chromium. It is highly...

Cloud geometry from oxygen-A-band observations through an aircraft side window

During the ACRIDICON-CHUVA (Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems–Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (Global Precipitation Measurement)) aircraft campaign in September 2014 over the Amazon, among other topics, aerosol effects on the development of cloud microphysical profiles during the burning season were studied. Hyperspectral remote sensing with the imaging spectrometer specMACS provided cloud microphysical information for sun-illuminated cloud sides. In order to derive profiles of phase or effective radius from cloud side observations, vertical location information is indispensable. For this purpose, spectral measurements of cloud-side-reflected radiation in the oxygen A absorption band collected by specMACS were used to determine absorption path length between cloud sides and the instrument aboard the aircraft. From these data, horizontal distance and eventually vertical height were derived. It is shown that, depending on aircraft altitude and sensor viewing direction, an unambiguous relationship of absorption and distance exists and can be used to retrieve cloud geometrical parameters. A comparison to distance and height information from stereo image analysis (using data of an independent camera) demonstrates the efficiency of the approach. Uncertainty estimates due to method, instrument and environmental factors are provided. The main sources of uncertainty are unknown in cloud absorption path contributions due to complex 3-D geometry or unknown microphysical properties, variable surface albedo and aerosol distribution. A systematic difference of 3.8 km between the stereo and spectral method is found which can be attributed to 3-D geometry effects not considered in the method's simplified cloud model. If this offset is considered, typical differences found are 1.6 km for distance and 230 m for vertical position at a typical distance around 20 km between sensor and convective cloud elements of typically 1–10 km horizontal and vertical extent.

Cloud geometry from oxygen-A band observations through an aircraft side window

During the ACRIDICON-CHUVA aircraft campaign in September 2014 over the Amazon, among other topics aerosol effects on the development of cloud microphysical profiles during the burning season were studied. Hyperspectral remote sensing with the imaging spectrometer specMACS provided cloud microphysical information for sun-illuminated cloud sides. In order to derive profiles of phase or effective radius from cloud side observations vertical location information is indispensable. For this purpose, spectral measurements of cloud side reflected radiation in the oxygen-A absorption band collected by specMACS were used to determine absorption path length between cloud sides and the instrument aboard the aircraft. From these data horizontal distance and eventually vertical height were derived. It is shown that, depending on aircraft altitude and sensor viewing direction, an unambiguous relationship of absorption and distance exists and can be used to retrieve cloud geometrical parameters. A comparison to distance and height information from stereo image analysis (using data of an independent camera) demonstrates the efficiency of the approach. Uncertainty estimates due to method, instrument and environmental factors are provided by the method. Main sources of uncertainty are unknown in-cloud absorption path contributions due to complex 3D geometry or unknown microphysical properties, variable surface albedo and aerosol distribution. A systematic difference of 3.8 km between stereo and spectral method is found which can be attributed to 3D geometry effects not considered in the methods simplified cloud model. If this offset is considered, typical differences found are 1.6 km for distance and 230 m for vertical position at a tpyical distance around 20 km between sensor and convective cloud elements of typically 1–10 km horizontal and vertical extent.

Mango-bagasse functional-confectionery: vehicle for enhancing bioaccessibility and permeability of phenolic compounds

Study on bioaccessibility and absorption path of mango bagasse phenolics.

HONO Measurement by Differential Photolysis

Nitrous acid (HONO) has been quantitatively measured in-situ by differential photolysis at 385 and 395 nm and subsequent detection as nitric oxide (NO) by the chemiluminescence reaction with ozone (O3). The technique has been evaluated by FT-IR to provide a direct HONO measurement in a simulation chamber, and compared side-by-side with a LOng Absorption Path Optical Photometer (LOPAP) in the field. The NO/O3 chemiluminescence technique is robust, well characterized and capable of sampling at low pressure whilst solid-state converter technology allows for unattended in-situ HONO measurements in combination with fast time resolution and response.