1,618 research outputs found

    Addition of aliphatic amines to montmorillonite to improve its adsorption capacity for organic pollutants in aqueous solution

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    Adsorption is one of the prominent separation techniques used in the treatment of wastewaters containing soluble organics. Activated carbon has been employed almost exclusively in adsorbing the 129 priority pollutants , as defined by the Environmental Protection Agency (EPA), from water and wastewater. Synthetic resins have recently begun to receive attention, but are derived from energy related sources, as is activated carbon. A few clays have been considered for use as adsorbents, but in nearly all cases the clays were used in their natural state. This research has explored the addition of the chloride salts of propylamine, dodecylamine, and dodecyldiamine to sodium montmorillonite (a smectite) in an attempt to improve its adsorptive capacity for removing organics from water and wastewater. X-ray diffraction analysis, differential thermal and thermogravimetric analyses, infrared spectroscopy, and scanning electron microscopy, were used to determine the interaction between montmorillonite and the alkylammonium salts. Replacement of exchangeable cations on the interlamellar surface of montmorillonite with alkylammonium ions has been shown by several researchers to permit ready intercalation of a wide variety of polar and nonpolar organic species. Adsorption isotherms conducted with acetaldehyde, acetone, benzene, butanol, chloroform, dimethylphthalate, hexanol, nitrobenzene, octanol, phenol, and toluene as the solutes showed some indication of intercalation of these eleven organic compounds. Intercalation of these compounds at low organic solution concentrations, 100 and 1,000 milligrams per liter, was found within the scope of the present study by x-ray diffraction and gas chromatography techniques not to be sufficient to make the alkylammonium-montmorillonites or the untreated montmorillonite totally competitive with current adsorbents used in the water and wastewater field. Adsorption of the eleven organic pollutants by the clays generally ranged from 10 to 50 percent of the amounts expected to be adsorbed on activated carbon at similar solute concentrations. Intercalation noted at high organic solution concentrations, up to 100 percent, was more significant and suggests the clays would be efficient in removing these organics at higher concentrations. X-ray diffraction results obtained make it possible to predict the orientation of the three alkylammonium ions and the eleven organic compounds in the interlamellar space of the montmorillonites

    Advances in high-speed store separation for upward-ejected stores and dynamic cavity doors

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    As technology continues to evolve for aircraft-deployed weapons, computational approaches to store separation analysis face new challenges. Anticipating vehicle designs that require upward store ejection, this study uses computational fluid dynamics and 6DoF motion analysis to predict such store trajectories in high-speed flow. Several store designs are analyzed at various ejection velocities in Mach 4 and Mach 6 conditions. The trajectory results show that streamlined store geometries may not induce sufficient drag to clear the aircraft after ejection. However, store designs with drag-enhancing features show potential for safe separation trajectories. To account for the unsteady effects of a cavity door which opens just prior to store ejection, dynamic cavity door simulations are presented, comparing their results to a quasi-static approach. The results show that such cavity opening effects impact pressure loads on the store, which may be critical for accurate store trajectory predictions

    Hydrogen-Based Activity Enhancement in Sediment Cultures and Intact Sediments

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    The potential for hydrogen gas to stimulate microbial respiratory activity in sediments was investigated. Cell elutions from Passaic River (NJ), San Diego Bay (CA), and Marine Harbor sediments were amended with hydrogen gas to evaluate its impact on microbial activity measured by intracellular reduction of 5-cyano-2,3-ditolyl tetrazolium chloride (CTC). The transferability of this approach to sediment slurries and static sediment columns was evaluated based on microbial activity enhancement in Marine Harbor sediments. Results indicate that microbial activity can be increased by a factor of 2–3 at a threshold hydrogen concentration range (0.5 to 1.5 μM). Terminal restriction fragment (T-RF) length polymorphism analysis indicated that the community response to hydrogen resulted in the emergence of previously recessive populations. The causal relationship between hydrogen amendment and an increase in CTC-active cells was most likely due to community structure shifts, as evidenced by the emergence of new T-RFs (19% of total) at hydrogen concentrations above 1.5 μM. No RF was dominant within this emergent group, and no chlororespirers were detected within this group, the latter probably due to the lack of enrichment of halogenated compounds. Nevertheless, the transferability of the observed relationship between hydrogen gas amendment and microbial activity to complex sediment samples suggests a promising remedial strategy for in place contaminated estuarine sediments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63230/1/ees.2006.0078.pd

    Spectral Polarization of the Redshifted 21 cm Absorption Line Toward 3C 286

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    A re-analysis of the Stokes-parameter spectra obtained of the z=0.692 21 cm absorption line toward 3C 286 shows that our original claimed detection of Zeeman splitting by a line-of-sight magnetic field, B_los = 87 microgauss is incorrect. Because of an insidious software error, what we reported as Stokes V is actually Stokes U: the revised Stokes V spectrum indicates a 3-sigma upper limit of B_los < 17 microgauss. The correct analysis reveals an absorption feature in fractional polarization that is offset in velocity from the Stokes I spectrum by -1.9 km/s. The polarization position-angle spectrum shows a dip that is also significantly offset from the Stokes I feature, but at a velocity that differs slightly from the absorption feature in fractional polarization. We model the absorption feature with 3 velocity components against the core-jet structure of 3C 286. Our chisquare minimization fitting results in components with differing (1) ratios of H I column density to spin temperature, (2) velocity centroids, and (3) velocity dispersions. The change in polarization position angle with frequency implies incomplete coverage of the background jet source by the absorber. It also implies a spatial variation of the polarization position angle across the jet source, which is observed at frequencies higher than the 839.4 MHz absorption frequency. The multi-component structure of the gas is best understood in terms of components with spatial scales of ~100 pc comprised of hundreds of low-temperature (T < 200 K) clouds with linear dimensions of about 1 pc.Comment: Accepted for Publication by the Astrophysical Journa

    HOMEOWNER DECISION MAKING AND BEHAVIOR RELATING TO DEEP HOME RETROFITS - Results of Homeowner Interviews

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    Volleyball Overhead Swing Volume and Injury Frequency over the Course of a Season

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    Background: Overuse injuries are common in volleyball; however, few studies exist that quantify the workload of a volleyball athlete in a season. The relationship between workload and shoulder injury has not been extensively studied in women\u27s collegiate volleyball athletes. Hypothesis/Purpose: This study aims to quantify shoulder workloads by counting overhead swings during practice and matches. The purpose of the current study is to provide a complete depiction of typical overhead swings, serves, and hits, which occur in both practices and matches. The primary hypothesis was that significantly more swings will occur in practices compared to matches. The secondary hypothesis was that greater swing volume and greater musculoskeletal injury frequency will occur in the pre-season than during the season. Study Design: Prospective cohort. Methods: Researchers observed practice and match videos and counted overhead serves and attacks of 19 women\u27s collegiate volleyball players for two seasons. Serves, overhead hits, and total swings (serves + hits) were the dependent variables; event (matches and practice) along with position (defensive specialists, setter, outside hitter, and middle blocker) were the independent variables. Musculoskeletal injury frequency and swing volume workload were compared across pre-season and competitive season time periods. Results: Across all positions except outside hitters twice as many total swings occurred in practices compared to matches (p = .002) resulting in an average of 19 (CI95 16.5, 21.5) more swings in practice than in matches. The average number of total swings during the pre-season 47.1 (CI95 44.1, 50.1) was significantly greater than average swings per session during the competitive season 37.7 (CI95 36.4, 38.9) (p \u3c 0.001) resulting in a mean difference of 9.4 (CI95 6.1, 12.7) swings. The number of athletes limited in participation or out due to a musculoskeletal injury during the pre-season (2.9%) was greater than during the season (1.1%) (p = 0.042). Conclusion: These findings support the primary hypothesis that women\u27s collegiate volleyball athletes swing more during practices than in matches. The higher average number of serves in the pre-season and the greater frequency of musculoskeletal injuries requiring participation restriction or removal from participation suggest that a concordant relationship may exist between workload and injury variables. Level of Evidence: 2

    Engaging stakeholders to improve innovation in the water industry

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    The majority of our nation's drinking water suppliers are small systems serving 25 to 3,300 people. It was recognized by U.S. EPA that to bring these small community systems into satisfactory compliance would necessitate new thinking and flexibility in terms of technology applications. Unfortunately, innovation in public water systems (PWSs) that provide drinking water to consumers is lacking. This lack of innovation is not due to technological advancements but rather due to institutional constraints. These institutional constraints may be U.S. EPA regulations or state regulatory rules, but also cultural norms and career incentives that reward conservative choices by drinking water utilities in communities and regulators. These institutional constraints pose greater challenges for small and medium communities and even result in greater economic burdens and lower public health protection than for comparable large communities. This presentation will describe the process to develop design criteria for low-pressure membranes that Ohio EPA will use as a supplement to the 10 state standards with the goal of improving innovation for water utilities in Ohio. Particularly, the Ohio Water Resources Center (WRC) at Ohio State has been working in conjunction with Ohio AWWA, regulators (Ohio EPA and U.S. EPA), utilities, manufacturers, and design professionals to lay out a framework for the design criteria by performing the following tasks: 1. identifying and selecting a relevant emerging technology in collaboration with our partners; 2. contacting the regulators, design professionals, and manufacturers of these technologies and composing a list of where microfiltration or ultrafiltration is currently in operation; 3. collecting sufficient full-scale data from these operating systems; 4. determining operating parameter(s) used to develop design criteria; 5. drafting design criteria for discussion among Ohio WRC, Ohio EPA and Ohio AWWA; 6. working effectively in a consensus-building process with Ohio EPA and these other stakeholders to come to agreement on final design criteria to be used by Ohio EPA in its approval process. Success of this project will eliminate the currently required pre-design demonstration study (typically at the pilot scale) for low-pressure membranes – significantly reducing the cost and project schedule for small and medium PWSs in Ohio to install current treatment technologies that are more cost effective and appropriate for treating the associated source water. Continued communication of progress on the supplemental design criteria for low-pressure membranes ensures that the project receives valuable input from stakeholders and strengthens the final product to provide the greatest benefit to PWSs throughout Ohio. The presentation will inform audience members of the project learnings and inspire interest in further work to propel innovation in the water industry.AUTHOR AFFILIATION: Zuzana Bohrerova, research specialist; associate director, Ohio State Department of Civil, Environmental and Geodetic Engineering, [email protected] (Corresponding Author); Ohio Water Resources Center; Linda Weavers, professor and John C. Geupel Chair; co-director, Ohio State Department of Civil, Environmental and Geodetic Engineering; Ohio Water Resources Center; Timothy Wolfe, senior consultant and VP emeritus; adjunct faculty, Stantec Consulting Services, Inc; Ohio State Department of Civil, Environmental and Geodetic Engineering; Megan Patterson, graduate research associate; Environmental EIT, Ohio State Department of Civil, Environmental and Geodetic Engineering, Stantec Consulting Services, Inc.The majority of drinking water suppliers in the United States are small systems serving 25 to 3,300 people. Innovation in public water systems (PWSs) is lacking, not due to technological advancements, but rather due to institutional constraints that pose greater challenges for small and medium communities and result in greater economic burdens and lower public health protection than for large communities. The Ohio Water Resources Center (WRC) is developing design criteria for a treatment technology that Ohio EPA will use as a supplement to the 10 state standards. Success of this project will eliminate the currently required pre-design demonstration study for low-pressure membranes – significantly reducing the cost and project schedule for small and medium PWSs in Ohio to install this technology where it is more cost effective and appropriate. We will inform audience members of the project learnings and inspire interest in further work to propel innovation in the water industry

    High-Sensitivity Serum Calcitonin Assays Applied to Screening for Thyroid C-Cell Disease in Multiple Endocrine Neoplasia Type 2A

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    Two serum calcitonin assays with sensitivities ≤ 10 pg/mL were compared to our standard radioimmunoassay (sensitivity 100 pg/mL) in multiple endocrine neoplasia type 2A (MEN 2A) screening. Values from the Nichols displacement radioimmunoassay averaged 38% higher than values from the CIS immunoradiometric assay; values from both were highly correlated, r = 0.845. In three individuals, both of the newer assays revealed abnormalities in pentagastrin tests three to four years before abnormalities were detected by the standard assay. Pentagastrin tests after total thyroidectomy were assayed by the newer methods in patients with medullary thyroid carcinoma (MTC) diagnosed at initial testing (group I); in patients with early MTC diagnosed by prospective screening (group ll); and in patients with pure C-cell hyperplasia detected by prospective screening (group III). At least 64% of group I, at least 25% of group II, but none of group III had detectable postoperative C-cell function. Conclusions: 1) The previous estimate of 12 years as median age of onset of C-cell disease in MEN 2A is probably three to four years too old. 2) Patients diagnosed with early MTC by screening had not necessarily skipped a preneoplastic phase of C-cell hyperplasia. At least some early disease was not detected by the standard assay. Higher sensitivity assays should improve screening for C-cell disease by earlier disease detection. 3) Biochemical cure by thyroidectomy after the development of MTC is not as frequent as previously thought, but the apparent cure rate of pure C-cell hyperplasia remains 100%

    An 84 microGauss Magnetic Field in a Galaxy at Redshift z=0.692

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    The magnetic field pervading our Galaxy is a crucial constituent of the interstellar medium: it mediates the dynamics of interstellar clouds, the energy density of cosmic rays, and the formation of stars. The field associated with ionized interstellar gas has been determined through observations of pulsars in our Galaxy. Radio-frequency measurements of pulse dispersion and the rotation of the plane of linear polarization, i.e., Faraday rotation, yield an average value B ~ 3 microGauss. The possible detection of Faraday rotation of linearly polarized photons emitted by high-redshift quasars suggests similar magnetic fields are present in foreground galaxies with redshifts z > 1. As Faraday rotation alone, however, determines neither the magnitude nor the redshift of the magnetic field, the strength of galactic magnetic fields at redshifts z > 0 remains uncertain. Here we report a measurement of a magnetic field of B ~ 84 microGauss in a galaxy at z =0.692, using the same Zeeman-splitting technique that revealed an average value of B = 6 microGauss in the neutral interstellar gas of our Galaxy. This is unexpected, as the leading theory of magnetic field generation, the mean-field dynamo model, predicts large-scale magnetic fields to be weaker in the past rather than stronger
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