The potential long-term influence of fly ash and lime-stabilized sewage sludge on mine spoil reclamation : simulated weathering

Surface mining allows pyrite to be brought to the surface, where it is readily oxidized, producing acid mine drainage. A feasible alternative for the reclamation of mine spoil is the utilization of lime-stabilized sewage sludge (LSS) and fly ash (FA). Lime-stabilized sewage sludge provides essential nutrients to assist in revegetation efforts in an otherwise deficient environment, provides organic matter to improve spoil physical characteristics, and provides a mechanism for disposal. Using a neutral FA in co-application with LSS can enhance mine spoil nutrient levels and physical characteristics. The University of Tennessee, Tennessee Valley Authority, and Electric Power Research Institute initiated a field study in 1994 to address the feasibility of LSS and FA co-utilization for mine spoil reclamation. To complement the field study, simulated laboratory weathering of unamended and amended mine spoil was initiated to assess the potential long-term influence of LSS and FA on mine spoil systems. The total elemental content of the FA, LSS, and mine spoil was determined by employing both HNO3 extraction and total digestion (aqua regia/HF). The percent recovery of elements by HNO3 digestion was determined by dividing the HNO3-extractable concentrations by the total elemental content determined using the aqua regia/HF method. Variations in HNO3-extractability of metals in the mine spoil, LSS, and FA was a function of element speciation in the mineral phase. In general, HNO3 digestion was more efficient at extracting Al, Ca, Mg, Cr, Cu, Pb, and Zn from LSS; K and Na from the FA; and Fe, Mg, P, Co, and Mn from mine spoil. Further, HNO3-extractability was not a function of total concentrations and the HNO3 digestion method did not yield a constant percent extractability that could be uniformly applied, irrespective of material. The chemical analyses of amended mine spoil leachates showed a neutralization of acidity generated by pyrite oxidation. Slight pH and nitrate fluctuations were observed during the later weathering cycles, which may have been due to increased microbial activity. Also, the initially high electrical conductivity (EC) of the mine spoil leachates was increased further upon LSS application and did not vary with FA rate. The EC of all mine spoil leachates decreased with weathering and mirrored the behavior of Ca and SO4. The dissolution and mobilization of Al, Fe, K, Cu, Mn, Ni, and Zn decreased upon LSS application, irrespective of FA rate. A sequential-selective dissolution (SSD) procedure partitioned elements (Ba, Co, Cr, Cu, Mn, Ni, Pb, Sr, and Zn) into the following operationally-defined pools: (1) soluble-exchangeable, (2) adsorbed, (3) organic, (4) carbonate, (5) sulfide, and (6)residual. The speciation of Ba increased in the soluble-exchangeable and carbonate fractions with increasing FA rate. Strontium increased in the soluble-exchangeable and sulfide fractions with increasing FA rate. Weathering tended to shift Ba to the carbonate fraction and Sr showed no significant shifts to any other phase. Chromium found in the residual fraction significantly increased upon LSS application. Weathering of the LSS-amended mine spoil increased Cr found in the adsorbed fraction, yet maintained predominance in the residual fraction. Chromium solid-phase speciation was not impacted by FA application or weathering. Although primarily found in the residual fraction, Co showed a significant decrease in the soluble-exchangeable form upon LSS and FA application in the weathered material. In general, FA did not impact Co solid-phase speciation. However, LSS application decreased Co found in the soluble-exchangeable fraction. Copper speciation decreased in the soluble-exchangeable and residual fractions upon LSS application with an increase in the carbonate fraction. Primarily, weathering shifted Cu into the residual forms. Fly ash rate had no influence on Cu speciation for the weathered or unweathered mine spoil. In general, increasing FA rate increased Ni found in the residual fraction. Weathering shifted Ni into the carbonate and sulfide forms which decreased with FA application rate. However, Mn was primarily found in the soluble-exchangeable and residual fractions, irrespective of amendment. Weathering shifted Mn into the carbonate form in the amended mine spoil upon LSS application and into the residual form for the unamended mine spoil. Upon LSS application, Pb decreased in the soluble-exchangeable fraction. However, when weathered, amendment did not influence Pb solid-phase speciation. In general, FA rate increased the carbonate form of Zn in the unweathered material. However, weathering shifted Zn from the soluble-exchangeable and sulfide forms into the carbonate fraction, which was influenced by the LSS. In general, the impact of FA co-application with LSS was element specific with respect to the solid-phase speciation of elements

Knowledge, Norms and Preferences for Tamarisk Management in the Green and Colorado River Corridors of the Colorado Plateau

Extensive research exists regarding invasive alien plant species including impacts to native ecosystems and efficacy of control methods on public lands and river corridors. Many studies have identified the need for more research regarding the social implications of invasive alien species management. More specifically, additional research is needed regarding the impacts of invasive alien plant management on the Colorado Plateau to river-based recreation experiences. It is important for public land management agencies like the National Park Service to understand recreation-based stakeholders’ knowledge, norms, and preferences toward managing prevalent alien plants like tamarisk. For this study, 330 river users were questioned about their knowledge of tamarisk and preferences for tamarisk management on the Green and Colorado River corridors of the Colorado Plateau. Results show that a majority of river users want tamarisk to be removed. The tamarisk control methods investigated in this thesis were also evaluated by respondents as acceptable. The methods evaluated to be the most acceptable were the cut-stump method and the use of tamarisk leaf beetle, while prescribed fire and the use of a machine to mulch tamarisk were found to be less acceptable. The use of chainsaws to perform the cut-stump method was found to be acceptable in both the Green and Colorado River corridors. This thesis concludes with a summary of findings and implications for land managers and future research

Enantioselective Total Synthesis of Macfarlandin C, a Spongian Diterpenoid Harboring a Concave-Substituted cis-Dioxabicyclo[3.3.0]octanone Fragment.

The enantioselective total synthesis of the rearranged spongian diterpenoid (-)-macfarlandin C is reported. This is the first synthesis of a rearranged spongian diterpenoid in which the bulky hydrocarbon fragment is joined via a quaternary carbon to the highly hindered concave face of the cis-2,8-dioxabicyclo[3.3.0]octan-3-one moiety. The strategy involves a late-stage fragment coupling between a tertiary carbon radical and an electrophilic butenolide resulting in the stereoselective formation of vicinal quaternary and tertiary stereocenters. A stereoselective Mukaiyama hydration that orients a pendant carboxymethyl side chain cis to the bulky octahydronapthalene substituent was pivotal in fashioning the challenging concave-substituted cis-dioxabicyclo[3.3.0]octanone fragment

Human Neonatal Keratinocytes Have Very High Levels of Cellular Vitamin A-Binding Proteins

Since cellular retinol- and retinoic acid-binding proteins (CRBP and CRABP) mediate the effects of vitamin A on epidermal differentiation, the levels of these binding proteins were measured in the epidermal and dermal layers of newborn, human foreskin as well as in primary cultures of keratinocytes and fibroblasts from these layers. ligand binding assays w3ith saturating concentrations of all trans-[3H]retinol or of all trans-[11-3H]retinoic acid were used to quantitate amounts of binding proteins in cytosols prepared form these skin layers or cultured cells. The epidermal levels of CRABP and CRBP (60.9 ± 14.4 and 7.3 ± 1.7 pmol per mg cytosol protein, respectively) were markedly higher than that reported for adult epidermis but wer comparable to levels in keratinocytes cultured from neonatal foreskin epidermis (61.8 ± 7.8 and 10.7 ± 2.5, respectively). The levels of CRABP were much lower in the foreskin dermis than in the epidermis and the levels measured in the fibroblasts cultured form this dermis were consistent with the dermal levels. however, CRBP levels in cultured dermal fibroblasts were very low and could not account for the dermal CRBP levels, suggesting that another dermal cell type has high levels of CRBP

Quick actuating closure and handling system

A quick activating closure and handling system, which utilizes conical sections for locking, was developed to allow quick access to the combustor internal components of the 8 ft High Temperature Tunnel. These critical components include the existing methane spraybar, a transpiration cooled nozzle and the new liquid oxygen (LOX) injection system housed within the combustor. A substantial cost savings will be realized once the mechanism is installed since it will substantially reduce the access time and increase the time available for conducting wind tunnel tests. A need exists for more frequent inspections when the wind tunnel operates at the more severe conditions generated by using LOX in the combustor. A loads analysis and a structural (finite element) analysis were conducted to verify that the new closure system is compatible with the existing pressure shell. In addition, strain gages were placed on the pressure vessel to verify how the pressure shell reacts to transient pressure loads. A scale model of the new closure system was built to verify the operation of the conical sections in the locking mechanisms

Chemical recycling of scrap composites

There are no well-developed technologies for recycling composite materials other than grinding to produce fillers. New approaches are needed to reclaim these valuable resources. Chemical or tertiary recycling, conversion of polymers into low molecular weight hydrocarbons for reuse as chemicals or fuels, is emerging as the most practical means for obtaining value from waste plastics and composites. Adherent Technologies is exploring a low-temperature catalytic process for recycling plastics and composites. Laboratory results show that all types of plastics, thermosets as well as thermoplastics, can be converted in high yields to valuable hydrocarbon products. This novel catalytic process runs at 200 C, conversion times are rapid, the process is closed and, thus, nonpolluting, and no highly toxic gas or liquid products have been observed so no negative environmental impact will result from its implementation. Tests on reclamation of composite materials show that epoxy, imide, and engineering thermoplastic matrices can be converted to low molecular weight hydrocarbons leaving behind the reinforcing fibers for reuse as composite reinforcements in secondary, lower-performance applications. Chemical recycling is also a means to dispose of sensitive or classified organic materials without incineration and provides a means to eliminate or reduce mixed hazardous wastes containing organic materials

What women know: Perceptions of seven female superintendents

An anomalous concentration of female superintendents in mostly rural South Texas prompted this inquiry. South Texas faces critical shortages in personnel due to impending retirement and turnover of existing school administrators and superintendents (Wesson & Marshall, 2012). It is difficult to recruit and retain the best talent necessary to solve tough school improvement challenges—high dropout rates, high poverty, low student achievement, and complex multi-cultural issues—in high needs, Hispanic majority, primarily rural school districts (Trevino Jr., Braley, Brown, & Slate, 2008; Wesson & Marshall, 2012). Krüger (2008) stated women are stronger educational leaders than men. Females seek and obtain leadership credentials for the express purpose of impacting education for students (Young & McLeod, 2001). Schools of all sizes and levels with female administrators achieved higher student success than schools with male administrators, according to a 7000 campus Texas study, in the 2006-2007 academic year (Roser, Brown, & Kelsey, 2009). In every ethnic group, women earn more doctoral degrees in education than men; women earn bachelors and masters degrees in education in proportion to their representation in the field; and women have more years of teaching experience than men (Shakeshaft, Brown, Irby, Grogan, & Ballenger, 2007). Women also outnumber men in education administration preparation programs (Petrie & Lindauer, 2001). Yet women are not ascending to the superintendency in proportion to their representation in the education profession (Shakeshaft et al., 2007). This naturalistic study of seven female superintendents in South Texas, including leaders in large and small rural districts, illuminated perceptions and experiences of female school leadership through portraiture and lent insight into common themes of aspiration and motivation

Psilocybin with Acceptance and Commitment Therapy (ACT) for the Treatment of Social Anxiety Disorder (SAD)

Social Anxiety Disorder (SAD) is a debilitating mental health condition characterized by an overwhelming fear and anxiety of social rejection that can lead to chronic patterns of social behavioral avoidance. Despite the existence of traditional efficacious treatments, a significant number of individuals either do not respond to treatment or experience a recurrence of symptoms over extended periods, spanning 10-12 years. Acceptance and Commitment Therapy (ACT), a form of acceptance-based behavioral therapy considered part of the third wave of cognitive behavioral therapies, has shown promising results in early studies, comparable to those of Cognitive Behavioral Therapy (CBT) that is considered the first-line treatment for SAD. When combined with Psychedelic-Assisted Psychotherapy (PAP), ACT may offer a viable efficacious alternative. This combination has the potential to improve therapeutic outcomes by addressing the underlying emotional and behavioral patterns that perpetuate SAD through a biopsychosocial approach. This paper examines the theoretical basis, practical considerations, and potential challenges associated with this innovative treatment approach

Numerical simulations of chromospheric hard X-ray source sizes in solar flares

X-ray observations are a powerful diagnostic tool for transport, acceleration, and heating of electrons in solar flares. Height and size measurements of X-ray footpoints sources can be used to determine the chromospheric density and constrain the parameters of magnetic field convergence and electron pitch-angle evolution. We investigate the influence of the chromospheric density, magnetic mirroring and collisional pitch-angle scattering on the size of X-ray sources. The time-independent Fokker-Planck equation for electron transport is solved numerically and analytically to find the electron distribution as a function of height above the photosphere. From this distribution, the expected X-ray flux as a function of height, its peak height and full width at half maximum are calculated and compared with RHESSI observations. A purely instrumental explanation for the observed source size was ruled out by using simulated RHESSI images. We find that magnetic mirroring and collisional pitch-angle scattering tend to change the electron flux such that electrons are stopped higher in the atmosphere compared with the simple case with collisional energy loss only. However, the resulting X-ray flux is dominated by the density structure in the chromosphere and only marginal increases in source width are found. Very high loop densities (>10^{11} cm^{-3}) could explain the observed sizes at higher energies, but are unrealistic and would result in no footpoint emission below about 40 keV, contrary to observations. We conclude that within a monolithic density model the vertical sizes are given mostly by the density scale-height and are predicted smaller than the RHESSI results show.Comment: 19 pages, 9 figures, accepted for publication in Ap