1,111 research outputs found

    The adsorption of environmental pollutants in gas and aqueous media utilizing nano-scale materials

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    In this body of work, the synthesis and characterization of several nanoporous materials have been described, as well as the application of these materials towards environmentally positive means. Largely, this work involves porous carbon materials produced from the amino acid L-histidine, a porous carbon precursor high in nitrogen and oxygen. Although pyrolysis of this precursor alone produces a non-porous foam, the introduction of any of a number of activating agents is shown here to produce a variety of amorphous and highly porous carbon materials. While applications of these materials have a very wide range, in this body of work the adsorption of pollutants is emphasized. Among the aqueous pollutants, both textile dyes and pharmaceuticals were investigated for their abilities to be taken up by these porous carbon materials. Individually, many of the porous carbons were capable of the uptake of noteworthy quantities of various pollutants. Yet, a broader finding in this work was that it appears the ‘tuning' of properties on a porous carbon is required to target each different adsorbate; no single property is universally linked to higher capacities. Apart from aqueous pollutants, the adsorption of CO2 was thoroughly investigated on many porous carbons. Given their high nitrogen content, it was expected that these materials would do well for CO2 uptake. And indeed, it was found that several histidinederived porous carbons were capable of noteworthy capacities, such as 8.30 and 5.57 mmol g-1. Through investigation of the porous carbon textural and chemical properties, these capacities are ascribed to a mixture of physisorption and chemisorption processes. Finally, the adsorption of CO2 was investigated on an amine-coated porous silica. With the purpose of making such nano-scale materials more feasible, immobilization inside a bacterial cellulose framework is investigated. Ultimately, it was found that after finetuning the loading process, a functional hybrid material can be made that successfully immobilizes the adsorbent material without sacrificing the capture abilities

    Combinatorial structures in loops

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46265/1/209_2005_Article_BF01221880.pd

    A Two-Player Game of Life

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    We present a new extension of Conway's game of life for two players, which we call p2life. P2life allows one of two types of token, black or white, to inhabit a cell, and adds competitive elements into the birth and survival rules of the original game. We solve the mean-field equation for p2life and determine by simulation that the asymptotic density of p2life approaches 0.0362.Comment: 7 pages, 3 figure

    Post-Pandemic Predictors of Anxiety in College Students

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    Rates of anxiety among college students have increased significantly during the COVID-19 pandemic and have remained high (Elharake et al., 2023), placing students at risk for diminished academic performance, depression, and academic burnout (Rassaby et al., 2022). The goal of this study was to examine possible predictors of anxiety in a diverse group of undergraduate students post-pandemic, with the goal of informing future preventive intervention efforts. Maladaptive perfectionism, passive procrastination, active procrastination, cognitive flexibility, and social well-being were assessed as potential predictors of state and trait anxiety in a sample of 297 currently enrolled college students. Results showed that perfectionism and passive procrastination were the strongest predictors of anxiety; cognitive flexibility and social well-being were also significant correlates. These results suggest that anxiety in college students could be ameliorated by: (1) reducing the unrealistic expectations that often accompany perfectionism; (2) preventing students from developing habits of academic procrastination; (3) increasing students’ ability to respond flexibly to changing circumstances; and (4) helping students develop strategies to approach their social world more positively

    Search for active-sterile neutrino mixing using neutral-current interactions in NOvA

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    We report results from the first search for sterile neutrinos mixing with active neutrinos through a reduction in the rate of neutral-current interactions over a baseline of 810 km between the NOvA detectors. Analyzing a 14-kton detector equivalent exposure of 6.05×10^(20) protons-on-target in the NuMI beam at Fermilab, we observe 95 neutral-current candidates at the Far Detector compared with 83.5 ± 9.7(stat) ± 9.4(syst) events predicted assuming mixing only occurs between active neutrino species. No evidence for ν_μ→ν_s transitions is found. Interpreting these results within a 3+1 model, we place constraints on the mixing angles θ_(24) < 20.8° and θ_(34_ < 31.2° at the 90% C.L. for 0.05  eV^2 ≤ Δm^2_(41) ≤ 0.5  eV2, the range of mass splittings that produce no significant oscillations over the Near Detector baseline

    Contralateral manual compensation for velocity-dependent force perturbations

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    It is not yet clear how the temporal structure of a voluntary action is coded allowing coordinated bimanual responses. This study focuses on the adaptation to and compensation for a force profile presented to one stationary arm which is proportional to the velocity of the other moving arm. We hypothesised that subjects would exhibit predictive coordinative responses which would co-vary with the state of the moving arm. Our null hypothesis is that they develop a time-dependent template of forces appropriate to compensate for the imposed perturbation. Subjects were trained to make 500 ms duration reaching movements with their dominant right arm to a visual target. A force generated with a robotic arm that was proportional to the velocity of the moving arm and perpendicular to movement direction acted on their stationary left hand, either at the same time as the movement or delayed by 250 or 500 ms. Subjects rapidly learnt to minimise the final end-point error. In the delay conditions, the left hand moved in advance of the onset of the perturbing force. In test conditions with faster or slower movement of the right hand, the predictive actions of the left hand co-varied with movement speed. Compensation for movement-related forces appeared to be predictive but not based on an accurate force profile that was equal and opposite to the imposed perturbatio

    Localization dynamics in a binary two-dimensional cellular automaton: the Diffusion Rule

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    We study a two-dimensional cellular automaton (CA), called Diffusion Rule (DR), which exhibits diffusion-like dynamics of propagating patterns. In computational experiments we discover a wide range of mobile and stationary localizations (gliders, oscillators, glider guns, puffer trains, etc), analyze spatio-temporal dynamics of collisions between localizations, and discuss possible applications in unconventional computing.Comment: Accepted to Journal of Cellular Automat

    Constraints on Oscillation Parameters from ν_e Appearance and ν_μ Disappearance in NOvA

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    Results are reported from an improved measurement of ν_μ→ν_e transitions by the NOvA experiment. Using an exposure equivalent to 6.05×10^(20) protons on target, 33 ν_e candidates are observed with a background of 8.2±0.8 (syst.). Combined with the latest NOvA ν_μ disappearance data and external constraints from reactor experiments on sin^2 2θ_(13), the hypothesis of inverted mass hierarchy with θ_(23) in the lower octant is disfavored at greater than 93% C.L. for all values of δ_(CP)
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