Two of the greatest challenges facing the 21st century involve providing sustainable supplies of clean water and energy, two highly interrelated resources, at affordable costs. Membrane technology is expected to continue to dominate the water purification technologies owing to its energy efficiency. However, there is a need for improved membranes that have higher flux, are more selective, are less prone to various types of fouling, and are more resistant to the chemical environment, especially chlorine, of these processes. This article summarizes the nature of the global water problem and reviews the state of the art of membrane technology. Existing deficiencies of current membranes and the opportunities to resolve them with innovative polymer chemistry and physics are identified. Extensive background is provided to help the reader understand the fundamental issues involved. Ph.D. students and two postdoctoral fellows performing fundamental research in gas and liquid separations using polymer membranes and barrier packaging. His research group focuses on include structure/property correlation development for desalination and vapor separation membrane materials, new materials for hydrogen separation and natural gas purification, nanocomposite membranes, reactive barrier packaging materials, and new materials for improving fouling resistance and permeation performance in liquid separation membranes. His research is described in more than 250 publications, and he has coedited four books on these topics. He has won a number of national awards for his research contributions, including the ACS

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In previous studies of intergenerational relationships, geographic distance has been considered the most obvious factor influencing opportunity for frequency of contact between grandparents and grandchildren. This study presents findings from a survey of 70 international college students in the Unites States regarding perceived grandparental influence and relationship satisfaction with their "closest" grandparent. Results showed that participants' perceived influence of grandparents and relationship satisfaction was maintained despite decreased contact between grandparents and grandchildren. In addition, grandchildren who initiated contact were found to have a significant impact on relationship satisfaction. This study provides an understanding of distance, contact, and intergenerational relationships in an international context.