QUANTIFYING HYDRAULIC CONDUCTIVITY IN MINE DRAINAGE PASSIVE TREATMENT SYSTEM VERTICAL FLOW BIOREACTORS

Heavy industrial mining has occurred in the United States for more than 100 years, and in many cases, has led to large-scale environmental degradation, especially from historical operations where mining occurred prior to environmental regulations. Many of these derelict or abandoned operations discharge abandoned mine drainage (AMD), which contains ecotoxic metal-contamination that impairs receiving stream water quality and negatively impacts local ecology. Passive treatment systems (PTS) are cost effective treatment technologies that are designed to use relatively little fossil fuels and natural physicochemical (e.g., limestone dissolution) and biological (e.g., bacterial sulfate reduction) processes for the treatment of AMD. One of the key components of PTS are vertical flow bioreactors (VFBRs). VFBRs typically include waste organic materials as microbial substrates overlying rock drainage layers. They utilize the dissolution of limestone to generate alkalinity for neutralization of excess protons and promote sulfate-reducing bacteria for additional alkalinity generation and trace metal removal as sulfides. However, long-term operation and maintenance issues in PTS include decreased hydraulic conductivity in VFBRs. Decreased hydraulic conductivity leads to either water by-passing the cell or decreased treatment efficiencies. This research focused on quantifying the hydraulic conductivity and characterizing the organic layer in VFBRs of multiple passive treatment systems with the intention of developing plans for extending the lives of the treatment systems. VFBRs at the Mayer Ranch, Hartshorne and Red Oak PTS were selected for this study. This research used four different methods to estimate hydraulic conductivity in VFBRs that have been in operation for 8-15 years. Hydraulic conductivity was compared against several different treatment media characteristics. The hydraulic conductivity measurements ranged from 9.93x10-3 to 1.74x10-5 cm/s. The comparison of the hydraulic conductivity and the treatment media characteristics indicated a trend that as particle density increased the hydraulic conductivity decreased. The comparison of the different methods did not yield one definitive method, but found that site variables dictated that certain methods may be more accurate or viable than others. The results helped to characterize the treatment media and quantified the hydraulic conductivity of the treatment media of VFBRs

Using Commodity Graphics Hardware for Real-Time Digital Hologram View-Reconstruction

View-reconstruction and display is an important part of many applications in digital holography such as computer vision and microscopy. Thus far, this has been an offline procedure for megapixel sized holograms. This paper introduces an implementation of real-time view-reconstruction using programmable graphics hardware. The theory of Fresnel-based view-reconstruction is introduced, after which an implementation using stream programming is presented. Two different fast Fourier transform (FFT)-based reconstruction methods are implemented, as well as two different FFT strategies. The efficiency of the methods is evaluated and compared to a CPU-based implementation, providing over 100 times speedup for a hologram size of 2048 x 2048

Using Commodity Graphics Hardware for Real-Time Digital Hologram View-Reconstruction

View-reconstruction and display is an important part of many applications in digital holography such as computer vision and microscopy. Thus far, this has been an offline procedure for megapixel sized holograms. This paper introduces an implementation of real-time view-reconstruction using programmable graphics hardware. The theory of Fresnel-based view-reconstruction is introduced, after which an implementation using stream programming is presented. Two different fast Fourier transform (FFT)-based reconstruction methods are implemented, as well as two different FFT strategies. The efficiency of the methods is evaluated and compared to a CPU-based implementation, providing over 100 times speedup for a hologram size of 2048 x 2048

Heroin Use and Sex: Some Patterns in Miami-Dade County, Florida

Much of the literature on heroin and opioid addiction holds that regular, long-term users of heroin and other opioids lose interest in sex as their drug using careers lengthen. Analysis of self-reports collected from IDUs in two cross- sectional surveys on patterns of risk behavior in Miami-Dade County, Florida, reveals that large proportions of IDUs report using heroin before or during sex across a wide range of self-injection experience, from as little as twelve months to over 40 years. One half or more of respondents to both surveys reported using heroin in their recent sexual experiences, with similar proportions reported by both males and females. The same IDUs, however, tend not to report using prescription painkillers before or during sex. This finding indicates that co-occurring risk behavior related to both sexual behavior and heroin use may be more prevalent among long-term IDUs than previous literature has suggested

Fishery management plan series

Management plan discussing the three shrimp species found in the Gulf of Mexico and how to best utilize these resources for Texas

The Atacama Cosmology Telescope: Sunyaev Zel'dovich Selected Galaxy Clusters at 148 GHz in the 2008 Survey

We report on twenty-three clusters detected blindly as Sunyaev-Zel'dovich (SZ) decrements in a 148 GHz, 455 square-degree map of the southern sky made with data from the Atacama Cosmology Telescope 2008 observing season. All SZ detections announced in this work have confirmed optical counterparts. Ten of the clusters are new discoveries. One newly discovered cluster, ACT-CL J0102-4915, with a redshift of 0.75 (photometric), has an SZ decrement comparable to the most massive systems at lower redshifts. Simulations of the cluster recovery method reproduce the sample purity measured by optical follow-up. In particular, for clusters detected with a signal-to-noise ratio greater than six, simulations are consistent with optical follow-up that demonstrated this subsample is 100% pure. The simulations further imply that the total sample is 80% complete for clusters with mass in excess of 6x10^14 solar masses referenced to the cluster volume characterized by five hundred times the critical density. The Compton y -- X-ray luminosity mass comparison for the eleven best detected clusters visually agrees with both self-similar and non-adiabatic, simulation-derived scaling laws.Comment: 13 pages, 7 figures, Accepted for publication in Ap

Observing the First Stars and Black Holes

The high sensitivity of JWST will open a new window on the end of the cosmological dark ages. Small stellar clusters, with a stellar mass of several 10^6 M_sun, and low-mass black holes (BHs), with a mass of several 10^5 M_sun should be directly detectable out to redshift z=10, and individual supernovae (SNe) and gamma ray burst (GRB) afterglows are bright enough to be visible beyond this redshift. Dense primordial gas, in the process of collapsing from large scales to form protogalaxies, may also be possible to image through diffuse recombination line emission, possibly even before stars or BHs are formed. In this article, I discuss the key physical processes that are expected to have determined the sizes of the first star-clusters and black holes, and the prospect of studying these objects by direct detections with JWST and with other instruments. The direct light emitted by the very first stellar clusters and intermediate-mass black holes at z>10 will likely fall below JWST's detection threshold. However, JWST could reveal a decline at the faint-end of the high-redshift luminosity function, and thereby shed light on radiative and other feedback effects that operate at these early epochs. JWST will also have the sensitivity to detect individual SNe from beyond z=10. In a dedicated survey lasting for several weeks, thousands of SNe could be detected at z>6, with a redshift distribution extending to the formation of the very first stars at z>15. Using these SNe as tracers may be the only method to map out the earliest stages of the cosmic star-formation history. Finally, we point out that studying the earliest objects at high redshift will also offer a new window on the primordial power spectrum, on 100 times smaller scales than probed by current large-scale structure data.Comment: Invited contribution to "Astrophysics in the Next Decade: JWST and Concurrent Facilities", Astrophysics & Space Science Library, Eds. H. Thronson, A. Tielens, M. Stiavelli, Springer: Dordrecht (2008