University of Colorado Boulder

About: University of Colorado Boulder is a education organization based out in Boulder, Colorado, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 48794 authors who have published 115151 publications receiving 5387328 citations. The organization is also known as: CU Boulder & UCB.

Guide to CO2 Separations in Imidazolium-Based Room-Temperature Ionic Liquids

Abstract: Room-temperature ionic liquids (RTILs) are nonvolatile, tunable solvents that have generated significant interest across a wide variety of engineering applications. The use of RTILs as media for CO2 separations appears especially promising, with imidazolium-based salts at the center of this research effort. The solubilities of gases, particularly CO2, N2, and CH4, have been studied in a number of RTILs. Process temperature and the chemical structures of the cation and anion have significant impacts on gas solubility and gas pair selectivity. Models based on regular solution theory and group contributions are useful to predict and explain CO2 solubility and selectivity in imidazolium-based RTILs. In addition to their role as a physical solvent, RTILs might also be used in supported ionic liquid membranes (SILMs) as a highly permeable and selective transport medium. Performance data for SILMs indicates that they exhibit large permeabilities as well as CO2/N2 selectivities that outperform many polymer membra...

Dwindling groundwater resources in northern India, from satellite gravity observations.

Abstract: [1] Northern India and its surroundings, home to roughly 600 million people, is probably the most heavily irrigated region in the world. Temporal changes in Earth's gravity field in this region as recorded by the GRACE satellite mission, reveal a steady, large-scale mass loss that we attribute to excessive extraction of groundwater. Combining the GRACE data with hydrological models to remove natural variability, we conclude the region lost groundwater at a rate of 54 ± 9 km3/yr between April, 2002 (the start of the GRACE mission) and June, 2008. This is probably the largest rate of groundwater loss in any comparable-sized region on Earth. Its likely contribution to sea level rise is roughly equivalent to that from melting Alaskan glaciers. This trend, if sustained, will lead to a major water crisis in this region when this non-renewable resource is exhausted.

Unraveling the Mystery of Indian Monsoon Failure During El Niño

Abstract: The 132-year historical rainfall record reveals that severe droughts in India have always been accompanied by El Nino events. Yet El Nino events have not always produced severe droughts. We show that El Nino events with the warmest sea surface temperature (SST) anomalies in the central equatorial Pacific are more effective in focusing drought-producing subsidence over India than events with the warmest SSTs in the eastern equatorial Pacific. The physical basis for such different impacts is established using atmospheric general circulation model experiments forced with idealized tropical Pacific warmings. These findings have important implications for Indian monsoon forecasting.

Reassessing the reliability and validity of self-report delinquency measures

Abstract: Several issues related to the reliability and validity of self-report delinquency measures are raised and discussed. These include problems associated with the use of internal consistency as the measure of reliability, the level of reliability or precision required for different types of analyses, problems with the content validity of self-report measures, problems of overreporting and underreporting, problems with the use of official records as a validity check on self-reports, and the lack of any good criterion as a major obstacle in assessing the empirical validity of self-report measures. In the light of these problems, some cautions about the use of self-report measures are made.