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Full-Text Articles in Physical Sciences and Mathematics

An Update On Groundwater Conditions At The Site Of The York College Cuny Campus In Southeastern Queens County, New York City, Nazrul I. Khandaker, Stanley Schleifer, Zarine Ali, Edward A. Molteni Oct 2007

An Update On Groundwater Conditions At The Site Of The York College Cuny Campus In Southeastern Queens County, New York City, Nazrul I. Khandaker, Stanley Schleifer, Zarine Ali, Edward A. Molteni

Publications and Research

The wells operated by the Jamaica Water Supply Company in Queens represent the only large scale utilization of groundwater for public water supply in New York City in recent years. These wells were shut down, for the most part, beginning in 1996. Since that time, water table elevations in the area, which had been drawn down by the withdrawal activity of the Jamaica Water Supply Company, have risen significantly causing some high groundwater problems, including flooding of basements. The New York City Department of Environmental Protection (NYCDEP) has held public hearings on a contemplated resumption of ground water withdrawal in …


The Impact Of Receiver Aperture Design And Telescope Properties On Lidar Signal-To-Noise Ratio Improvements, Yasser Hassebo, Khaled El Sayed Feb 2007

The Impact Of Receiver Aperture Design And Telescope Properties On Lidar Signal-To-Noise Ratio Improvements, Yasser Hassebo, Khaled El Sayed

Publications and Research

Range and sensitivities of lidar measurements in daylight are limited by sky background noise power (BGP). This is particularly important for Raman lidar techniques where the Raman backscattered signal is relatively weak. This often restricts Raman lidar measurements to nighttime where BGP is absent. The background noise elimination is particularly important in daytime measurements in case where full overlap between laser beam and receiver telescope field-of-view (FOV) is necessary. Results of numerical simulations for a vertically pointing Lidar show that significant improvements in Lidar signal to noise ratio (SNR) can be obtained, by minimizing the detected sky BGP. This can …