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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.03.014 Byline: K.J. Lim (a), B.A. Engel (a), Z. Tang (a), S. Muthukrishnan (b), J. Choi (c), K. Kim (c) Abstract: Urbanization can result in alteration of a watershed's hydrologic response and water quality. To simulate hydrologic and water quality impacts of land use changes, the Long-Term Hydrologic Impact Assessment (L-THIA) system has been used. The L-THIA system estimates pollutant loading based on direct runoff quantity and land use based pollutant coefficients. The accurate estimation of direct runoff is important in assessing water quality impacts of land use changes. An automated program was developed to calibrate the L-THIA model using the millions of curve number (CN) combinations associated with land uses and hydrologic soil groups. L-THIA calibration for the Little Eagle Creek (LEC) watershed near Indianapolis, Indiana was performed using land use data for 1991 and daily rainfall data for six months of 1991 (January 1-June 30) to minimize errors associated with use of different temporal land use data and rainfall data. For the calibration period, the Nash-Sutcliffe coefficient was 0.60 for estimated and observed direct runoff. The calibrated CN values were used for validation of the model for the same year (July 1-December 31), and the Nash-Sutcliffe coefficient was 0.60 for estimated and observed direct runoff. The Nash-Sutcliffe coefficient was 0.52 for January 1, 1991 to December 31, 1991 using uncalibrated CN values. As shown in this study, the use of better input parameters for the L-THIA model can improve accuracy. The effects on direct runoff and pollutant estimation of the calibrated CN values in the L-THIA model were investigated for the LEC. Following calibration, the estimated average annual direct runoff for the LEC watershed increased by 34%, total nitrogen by 24%, total phosphorus by 22%, and total lead by 43%. This study demonstrates that the L-THIA model should be calibrated and validated prior to application in a particular watershed to more accurately assess the effects of land use changes on hydrology and water quality. Author Affiliation: (a) Department of Agricultural and Biological Engineering, Purdue University, 225 South University Street, West Lafayette, IN 47907-2093, USA (b) Department of Earth and Environmental Sciences, Furman University, Greenville, SC 29613, USA (c) Department of Agricultural Engineering, Kangwon National University, Chuncheon, Kangwon, South Korea Article History: Received 6 August 2004; Revised 16 March 2005; Accepted 18 March 2005

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2005.01.006 Byline: Z. Tang (a), B.A. Engel (a), B.C. Pijanowski (b), K.J. Lim (a) Abstract: Urban expansion is a major driving force altering local and regional hydrology and increasing non-point source (NPS) pollution. To explore these environmental consequences of urbanization, land use change was forecast, and long-term runoff and NPS pollution were assessed in the Muskegon River watershed, located on the eastern coast of Lake Michigan. A land use change model, LTM, and a web-based environmental impact model, L-THIA, were used in this study. The outcomes indicated the watershed would likely be subjected to impacts from urbanization on runoff and some types of NPS pollution. Urbanization will slightly or considerably increase runoff volume, depending on the development rate, slightly increase nutrient losses in runoff, but significantly increase losses of oil and grease and certain heavy metals in runoff. The spatial variation of urbanization and its impact were also evaluated at the subwatershed scale and showed subwatersheds along the coast of the lake and close to cities would have runoff and nitrogen impact. The results of this study have significant implications for urban planning and decision making in an effort to protect and remediate water and habitat quality of Muskegon Lake, which is one of Lake Michigan's Areas of Concern (AOC), and the techniques described here can be used in other areas. Author Affiliation: (a) Department of Agricultural and Biological Engineering, Purdue University, 225 South University Street, West Lafayette, IN 47907-2093, USA (b) Department of Forestry and Natural Resources, Purdue University, 195 Marsteller Street, West Lafayette, IN 47907-2093, USA

In this paper, the epoxy elasticity factors were investigated by thermomechanical analysis (TMA), dynamic mechanical thermal analysis (DMTA), thermogravimetric analysis (TGA) and field emission scanning electron microscope (FESEM) to improve toughness and reduce brittleness of existing epoxy resin. Dumbbell shaped specimens were made and tested at rates of 0, 20 and 35 parts per hundred resins (phr). TMA and DMTA temperatures ranged from -20 to 200[degrees]C and TGA ranged from 0 to 600[degrees]C. The glass transition temperature (Tg) of elastic epoxy was measured by thermal analysis. Also investigated were the thermal expansion coefficient (a), the high-temperature characteristics, modulus and the loss factor (Tan [delta]). We analyzed the structure using FESEM and have found elastomer particles (elastic-factors) in the elastic epoxy matrix. We have made elastic epoxy by adding elastomer particles to existing epoxy. Generally, the toughness of elastic epoxy can be improved by changing the structure of existing epoxy of poor impact-strength. In addition, we measured the permittivity and Tan [delta] for investigation of the electrical properties of elastic epoxy. The permittivity and Tan [delta] depend on the elastomer composition. Namely, the permittivity and Tan 6 increase according to the elastomer contents. For experimental analysis results, 20 phr was considered an excellent specimen. Index Terms--Elastic epoxy, high impact, high temperature, glass transition temperature, elastic-factor.

The breakdown and conduction characteristics in metal-insulator semiconductor (MIS) structures having a thin silicon nitride layer (5.8 to 8.3 nm) as insulator were investigated. The nitride layer was grown on a silicon wafer by low-pressure chemical vapor deposition. The characteristics of breakdown voltage, time-dependent dielectric breakdown, and current vs. voltage of the structure were measured.

An attempt is made to forecast and assess the impact of the predicted land use changes on long-term runoff and non-point source (NPS) pollution in the Muskegon River watershed, using an environmental impact analysis model. The implications of the results for decision-making and long-term urban planning are discussed.