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Full-Text Articles in Physical Sciences and Mathematics

Enhancing The Visibility Of Vernier Effect In A Tri-Microfiber Coupler Fiber Loop Interferometer For Ultrasensitive Refractive Index And Temperature Sensing, Fangfang Wei, Dejun Liu, Zhe Wang, Zhuochen Wang, Gerald Farrell, Qiang Wu, Gang-Ding Peng, Yuliya Semenova Nov 2020

Enhancing The Visibility Of Vernier Effect In A Tri-Microfiber Coupler Fiber Loop Interferometer For Ultrasensitive Refractive Index And Temperature Sensing, Fangfang Wei, Dejun Liu, Zhe Wang, Zhuochen Wang, Gerald Farrell, Qiang Wu, Gang-Ding Peng, Yuliya Semenova

Articles

In this paper a Vernier effect based sensor is analyzed and demonstrated experimentally in a tri-microfiber coupler (Tri-MFC) and polarization-maintaining fiber (PMF) loop interferometer (Tri-MFC-PMF) to provide ultrasensitive refractive index and temperature sensing. The main novelty of this work is an analysis of parameters of the proposed Tri-MFC-PMF with the objective of determining the conditions leading to a strong Vernier effect. It has been identified by simulation that the Vernier effect is a primary factor in the design of Tri-MFC-PMF loop sensing structure for sensitivity enhancement. It is furthermore demonstrated experimentally that enhancing the visibility of the Vernier spectrum in …


An Examination Of Enhanced Atmospheric Methane Detection Methods For Predicting Performance Of A Novel Multiband Uncooled Radiometer Imager, Cody M. Webber, John P. Kerekes Oct 2020

An Examination Of Enhanced Atmospheric Methane Detection Methods For Predicting Performance Of A Novel Multiband Uncooled Radiometer Imager, Cody M. Webber, John P. Kerekes

Articles

To evaluate the potential for a new uncooled infrared radiometer imager to detect enhanced atmospheric levels of methane, three different analysis methods were examined. A single-pixel brightness temperature to noise-equivalent delta temperature (NEdT) comparison study performed using data simulated from MODTRAN6 revealed that a single thermal band centered on the 7.68 µm methane feature leads to a detectable brightness temperature difference exceeding the sensor noise level for a plume of about 17 ppm at ambient atmospheric temperature compared to an ambient plume with no enhanced methane present. Application of a normalized differential methane index method, a novel approach for methane …


Volunteered And Crowdsourced Geographic Information: The Openstreetmap Project, Michela Bertolotto, Gavin Mcardle, Bianca Schoen-Phelan Jan 2020

Volunteered And Crowdsourced Geographic Information: The Openstreetmap Project, Michela Bertolotto, Gavin Mcardle, Bianca Schoen-Phelan

Articles

Advancements in technology over the last two decades have changed how spatial data are created and used. In particular, in the last decade, volunteered geographic information (VGI), i.e., the crowdsourcing of geographic information, has revolutionized the spatial domain by shifting the map-making process from the hands of experts to those of any willing contributor. Started in 2004, OpenStreetMap (OSM) is the pinnacle of VGI due to the large number of volunteers involved and the volume of spatial data generated. While the original objective of OSM was to create a free map of the world, its uses have shown how the …