Effective environmental management of DOE sites requires reliable prediction of reactive transport phenomena. A central issue in prediction of subsurface reactive transport is the impact of multiscale physical, chemical, and biological heterogeneity. Heterogeneity manifests itself through incomplete mixing of reactants at scales below those at which concentrations are explicitly defined (i.e., the numerical grid scale). This results in a mismatch between simulated reaction processes (formulated in terms of average concentrations) and actual processes (controlled by local concentrations). At the field scale, this results in apparent scale-dependence of model parameters and inability to utilize laboratory parameters in field models. Accordingly, most field modeling efforts are restricted to empirical estimation of model parameters by fitting to field observations, which renders extrapolation of model predictions beyond fitted conditions unreliable. The objective of this project is to develop a theoretical and computational framework for (1) connecting models of coupled reactive transport from pore-scale processes to field-scale bioremediation through a hierarchy of models that maintain crucial information from the smaller scales at the larger scales; and (2) quantifying the uncertainty that is introduced by both the upscaling process and uncertainty in physical parameters. One of the challenges of addressing scale-dependent effects of coupled processes in …

Poster presentation for the 2009 University Scholars Day at the University of North Texas discussing a comparison of education in China and the United States.

For the in situ reductive immobilization of U to be an acceptable strategy for the removal of that element from groundwater, the long-term stability of U(IV) must be determined. Rates of biotransformation of Fe species influence the mineralogy of the resulting products (Fredrickson et al., 2003; Senko et al., 2005), and we hypothesize that the rate of U(VI) reduction influences the mineralogy of resultant U(IV) precipitates. We hypothesize that slower rates of U(VI) reduction will yield U(IV) phases that are more resistant to reoxidation, and will therefore be more stable upon cessation of electron donor addition. U(IV) phases formed by relatively slow reduction may be more crystalline or larger in comparison to their relatively rapidly-formed counterparts (Figure 1), thus limiting the reactivity of slowly-formed U(IV) phases toward various oxidants. The physical location of U(IV) precipitates relative to bacterial cells may also limit the reactivity of biogenic U(IV) phases. In this situation, we expect that precipitation of U(IV) within the bacterial cell may protect U(IV) from reoxidation by limiting physical contact between U(IV) and oxidants (Figure 1). We assessed the effect of U(VI) reduction rate on the subsequent reoxidation of biogenic U(IV) and are currently conducting column scale studies to determine …

Poster presentation for the 2008 University Scholars Day at the University of North Texas discussing research on the lasting behavioral effects of altered prenatal development of the brain.

Poster presentation for the 2008 University Scholars Day at the University of North Texas discussing research on torture and threat-based perspectives.

This poster examines the relationships between self-efficacy in managing chronic disease, hope, and health perception in HIV+ adults who use contemporary and alternative medicines.

Poster presentation for the 2009 University Scholars Day at at the University of North Texas discussing research on DNA profiling and forensics.

Remediation and long-term stewardship of uranium-contaminated sediments and groundwaters are critical problems at a number of DOE facilities and mining sites. Some remediation strategies based on in-situ bioreduction of U are potentially effective in significantly decreasing U concentrations in groundwaters. However, a number of basic processes require understanding in order to identify conditions more conducive to success of reduction-based U stabilization. Our current research targets several of these issues including: (1) effects of organic carbon (OC) forms and supply rates on stability of bioreduced U, (2) the roles of Fe(III)- and Mn(III,IV)-oxides as potential U oxidants in sediments, and (3) microbial community changes in relation to U redox changes. These issues were identified in our previous study on U bioreduction and reoxidation (Wan et al., 2005). Most of our studies are being conducted on historically U-contaminated sediments from Area 2 of the Field Research Center, Oak Ridge National Laboratory, in flow-through columns simulating in-situ field remediation.

Poster from the Turtle Creek Chorale Collection for their "Paradise Found!" event on April 2nd and 5th at the Morton H. Meyerson Symphony Center.

Poster from the Turtle Creek Chorale Collection for their "The Passion of Joan of Arc" event which took place in April, 2004 at the Meyerson Symphony Center. A photograph of a person with their hands in front of their face in prayer appears in the center of the poster.

Poster from the Turtle Creek Chorale Collection advertising their production of Carl Orff's cantata "Carmina Burana". The concert took place at the Morton H. Meyerson Symphony Center and featured over 400 performers.

Pages from the 2008 URCM promotional materials. Each one has a different photograph and information about what the University of North Texas offers for possible future students. The first page includes an image of the Administration Building and a corner of Willis Library from the North.

Poster advertising a concert by One O'Clock Lab Band on April 30, 2009, at McDavid Studio.

A flier advertising a fashion show hosted by MOSÉ to raise money for HIV/AIDS. It includes date, time, and location and ticket information.

A flier notifying students that the FOCUS Bible Study on the UNT campus was cancelled for the night. There is also a contact email for interested students.

A flier advertising an event titled "GLBT History of the Nation and Dallas Revealed". It includes a short description and information about the date, time, and location of the presentation. The supporters of the event are listed at the bottom.

A flier advertising an event titled "Human Rights and Mayan Ethical Perspectives" with Jorge M. Rodriguez speaking. There is a Mayan calendar with a summary of the event's focus in the middle. The date, time, and location are also listed at the bottom.

A flier advertising a meeting of the Immigrant Labor Rights Tour. It includes the logo of the group and information about the event. The sponsors are listed beneath the summary.

A flier advertising a Native American Languages colloquium hosted by UNT. It lists the speakers and information about the date, time, and location of the event.

A flier advertising an event titled Neruda's Legacy in Chilean Society held at UNT. A professor from the Universidad de Concepción in Chile. It includes the location, date, and time as well as a short description of the event.

A document advertising a lecture titled "The New Era in Kuwait" with speakers Dr. Amer Al-Tameeni and Dr. Sami Al-Faraj. It includes a date, time, and location for the event and lists the UNT sponsors.

A flier advertising the need for volunteers at the '6th Annual Mean Green Blowout'. There is a description of the requirements for volunteers before the event happens and locations where they can sign up.

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Poster presentation for the 2008 University Scholars Day at the University of North Texas discussing research on expressions and acceptance of non-normative gender.