Physical Sciences and Mathematics Commons^™

Assessment Of Groundwater Resources In Selected Areas Of Al Ain In The U.A.E., Fatma Abdullatif Al Shahi

Theses

The sustainable development of any region depends on the availability of water resources. In arid and semi-arid regions, the shortage in freshwater resources constitutes the major constraint against the expansion in agricultural and industrial activities. Therefore, every possible effort should be made to assess, develop and sustain the limited freshwater water resource in such regions.

The United Arab Emirates (UAE) is located in an arid region, where the climate is harsh and the renewable freshwater resources are very limited. Despite the severe shortage in water resources, water is misused and sometimes wasted. The per capita daily consumption in the UAE …

Steady State Simulation Of Ysz Intermediate-Temperature Fuel Cell, Zi-Jing Lin, Ye Gu, Xiao-Hua Zhang

Journal of Electrochemistry

With a coupled 2D electrochemical and thermal modeling software, the characteristics of the steady state operation of the intermediate-temperature fuel cell with thin yttria-stabilized zirconia(YSZ) electrolyte was analyzed. The parameters of I-V equation were obtained from fitting the experiment results and the choice of grid points was determined by balancing the accuracy requirement and computational efficiency. The temperature fields at different operation circumstances such as flow designs, material choices for interconnect, were examined. The dependences of the output power and cell efficiency on the operating voltage at different temperatures were studied. Based upon the analysis of the temperature profile, it …

A Comparison Of Haloe V19 With Sage Ii V6.00 Ozone Observations Using Trajectory Mapping, Gary A. Morris, James F. Gleason, James M. Russell Iii, Mark R. Schoeberl, M. Patrick Mccormick

Physics and Astronomy Faculty Publications

We apply trajectory mapping to an 8-year intercomparison of ozone observations from the Halogen Occultation Experiment (HALOE) (V19) and Stratospheric Aerosol and Gas Experiment (SAGE) II (V6.00) for the months March, May, June, September, October, and December from the period December 1991 to October 1999. Our results, which represent the most extensive such intercomparison of these two data sets to date, suggest a root-mean-square difference between the two data sets of >15% below 22 km in the tropics and of 4–12% throughout most of the rest of the stratosphere. In addition, we find a bias with HALOE ozone low relative …

Anthropogenic Land-Use Change In The North American Tall Grass-Short Grass Transition And Modification Of Near-Surface Hydrologic Cycle, Rezaul Mamood, Kenneth Hubbard

School of Natural Resources: Faculty Publications

During the 19th and 20th centuries, the landscape of the North American Great Plains was rapidly modified from natural grasslands to agricultural farmlands. These changes affected much of the continent with potential impacts in grasslands equal to deforestation elsewhere. Therefore, the resulting impacts on weather and climate should be studied. In this study, a soil water balance model is applied for 3 land uses at 3 locations. These locations are representative of the east to west declining precipitation gradient of the Great Plains. It was found, in McCook, Nebraska, for example, that annual total evapotranspiration for irrigated maize is 36% …

Modeling Hydrogen Diffusion For Solar Cell Passivation And Process Optimization, Yi Zhang

Dissertations

A diffusion model for hydrogen (H) in crystalline silicon was established which takes into account the charged state conversion, junction field, mobile traps, and complex formation and dissociation at dopant and trap sites. Carrier exchange among the various charged species is a "fast" process compared to the diffusion process. A numerical method was developed to solve the densities of various charged species from the Poisson's equation that involves shallow-level dopants and one "negative U" impurity, e.g., H. Time domain implicit method was adopted in finite difference scheme to solve the fully coupled equations.

Limiting versions of the model were applied …

Smoke And Mirrors Or Science? Teaching Law With Computers - A Reply To Cass Sunstein On Artificial Intelligence And Legal Science, Eric A. Engle

Eric A. Engle

The article explores the possibilities and limits of AI for teaching and modeling law.

Extraction Equilibria Of Nicotinic Acid Using Alamine 300/Diluent And Conventional Solvent Systems, Aynur Şenol

Turkish Journal of Chemistry

The distribution of nicotinic acid between water and Alamine 300 (tri-n-octylamine) dissolved in various (proton-donating and -accepting, polar and nonpolar) diluents, and a comparison with the extraction equilibria of pure diluent alone were studied at 298 K and a phase ratio of 1:1 (v/v). The cyclic alcohol/amine system yielded the highest synergistic extraction efficiency. The strength of the complex solvation was found to be reasonably high for halogenated aliphatic hydrocarbons and nitrobenzene, activating mainly the formation of the acid_{1}-amine_{1} structure. The influence of the acid structure over distribution was evaluated through comparing the extractabilities of three acids containing different functional …

Modeling Of Taqi Endonuclease Purification By Hplc, Mehmet Düzenli̇, Kutlu Ö. Ülgen

Turkish Journal of Chemistry

The present work is based on the previously reported purification study of TaqI endonuclease^{5} and aimed to simulate the experimentally obtained chromatograms in order to reduce the time and cost in the design, optimization and scaling up of purification processes. Three different models depending on equilibrium, rate and plate theories are used in the mathematical description of experimental elution profiles and the solutions of the model equations are compared. The equilibrium-dispersive theory provides excellent results in predicting the experimental chromatograms. It is thus recognized that band dispersion takes place in the column through axial dispersion and nonequilibrium effects. The user-friendly …