763 research outputs found

    Method for forming articles having deep drawn portions from matted wood flakes

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    An article having non-planar portions, such as a material handling pallet, including a substantially flat deck member and a plurality of hollow leg members projecting integrally from the deck member, is molded as a one-piece unit from a loosely-felted mat formed from a mixture of resinous particle board binder and flake-like wood particles. The leg members are preformed in a separate preform mold or the article forming mold and the mat is deposited on the female die over mold cavities containing the preforms. When the article forming mold is closed, the mat and preforms are compressed into substantially the desired shape and size under temperature and pressure conditions which bond the wood particles of the mat and the preforms together to form a unitary structure.https://digitalcommons.mtu.edu/patents/1091/thumbnail.jp

    Comparative genetics of seven plants endemic to Florida’s Lake Wales Ridge

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    Here we submit that mathematical tools used in population viability analysis can be used in conjunction with floristic and faunistic surveys to predict changes in biogeographic range. We illustrate our point by summarizing the results of a demographic study of Lobelia boykinii. In this study we used deterministic and stochastic matrix models to estimate the growth rate and to predict the time to extinction for three populations growing in the Carolina bays. The stochastic model better discriminated among the fates of the three populations. It predicted extinction for two populations in the next 25 years but no extinction of the third population for at least 50 years. Probability of extinction is likely correlated with hydrologic regime and fire frequency of the bay in which a population is found. The stochastic model could be combined with information about the geographic distribution of L. boykinii habitats to predict short-term biogeographic change

    Severe Constraints on New Physics Explanations of the MiniBooNE Excess

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    The MiniBooNE experiment has recently reported an anomalous 4.5σ\sigma excess of electron-like events consistent with νe\nu_e appearance from a νμ\nu_\mu beam at short-baseline. Given the lack of corresponding νμ\nu_\mu disappearance observations, required in the case of oscillations involving a sterile flavor, there is strong motivation for alternative explanations of this anomaly. We consider the possibility that the observed electron-like signal may actually be due to hypothetical new particles,which do not involve new sources of neutrino production or oscillations. We find that the electron-like event energy and angular distributions in the full MiniBooNE data-set, including neutrino mode, antineutrino mode, and beam dump mode, severely limit, and in some cases rule out, new physics scenarios as an explanation for the observed neutrino and antineutrino mode excesses. Specifically, scenarios in which the new particle decays (visibly or semi-visibly) or scatters elastically in the detector are strongly disfavored. Using generic kinematic arguments, this paper extends the existing MiniBooNE results and interpretations to exhaustively constrain previously unconsidered new physics signatures and emphasizes the power of the MiniBooNE beam dump search to further constrain models for the excess.Comment: 6 pages, 3 figure

    Cohomology of the Lie Superalgebra of Contact Vector Fields on R11\mathbb{R}^{1|1} and Deformations of the Superspace of Symbols

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    Following Feigin and Fuchs, we compute the first cohomology of the Lie superalgebra K(1)\mathcal{K}(1) of contact vector fields on the (1,1)-dimensional real superspace with coefficients in the superspace of linear differential operators acting on the superspaces of weighted densities. We also compute the same, but osp(12)\mathfrak{osp}(1|2)-relative, cohomology. We explicitly give 1-cocycles spanning these cohomology. We classify generic formal osp(12)\mathfrak{osp}(1|2)-trivial deformations of the K(1)\mathcal{K}(1)-module structure on the superspaces of symbols of differential operators. We prove that any generic formal osp(12)\mathfrak{osp}(1|2)-trivial deformation of this K(1)\mathcal{K}(1)-module is equivalent to a polynomial one of degree 4\leq4. This work is the simplest superization of a result by Bouarroudj [On sl\mathfrak{sl}(2)-relative cohomology of the Lie algebra of vector fields and differential operators, J. Nonlinear Math. Phys., no.1, (2007), 112--127]. Further superizations correspond to osp(N2)\mathfrak{osp}(N|2)-relative cohomology of the Lie superalgebras of contact vector fields on 1N1|N-dimensional superspace

    Atomic Dark Matter

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    We propose that dark matter is dominantly comprised of atomic bound states. We build a simple model and map the parameter space that results in the early universe formation of hydrogen-like dark atoms. We find that atomic dark matter has interesting implications for cosmology as well as direct detection: Protohalo formation can be suppressed below Mproto103106MM_{proto} \sim 10^3 - 10^6 M_{\odot} for weak scale dark matter due to Ion-Radiation interactions in the dark sector. Moreover, weak-scale dark atoms can accommodate hyperfine splittings of order 100 \kev, consistent with the inelastic dark matter interpretation of the DAMA data while naturally evading direct detection bounds.Comment: 17 pages, 3 figure

    Predicción de las propiedades mecánicas de un hormigón utilizando técnicas inteligentes para reducir las emisiones de CO2

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    The contribution to global CO2 emissions from concrete production is increasing. In this paper, the effect of concrete mix constituents on the properties of concrete and CO2 emissions was investigated. The tested materials used 47 mixtures, consisting of ordinary Portland cement (OPC) type I, coarse aggregate, river sand and chemical admixtures. Response surface methodology (RSM) and particle swarm optimisation (PSO) algorithms were employed to evaluate the mix constituents at different levels simultaneously. Quadratic and line models were produced to fit the experimental results. Based on these models, the concrete mixture necessary to achieve optimum engineering properties was found using RSM and PSO. The resulting mixture required to obtain the desired mechanical properties for concrete was 1.10-2.00 fine aggregate/cement, 1.90-2.90 coarse aggregate/cement, 0.30-0.4 water/cement, and 0.01-0.013 chemical admixtures/cement. Both methods had over 94% accuracy, compared to the experimental results. Finally, by employing RSM and PSO methods, the number of experimental mixtures tested could be reduced, saving time and money, as well as decreasing CO2 emissions.La contribución a las emisiones globales de CO2 debidas a la producción de hormigón está aumentando. En este trabajo, se investigó el efecto de los componentes de la mezcla de hormigón en las propiedades del mismo y las emisiones de CO2. Los materiales estudiados fueron 47 mezclas, que consistieron en cemento Portland ordinario (OPC) tipo I, árido grueso, arena de río y aditivos químicos. Se utilizaron algoritmos de metodología de respuesta de superficie (RSM) y optimización de nube de partículas (PSO) para evaluar los componentes de la mezcla a diferentes niveles simultáneamente. Se elaboraron modelos cuadráticos y lineales para ajustar los resultados experimentales. Basándose en estos modelos, utilizando RSM y PSO, la mezcla de hormigón logró propiedades óptimas de ingeniería. La mezcla resultante requerida para obtener las propiedades mecánicas deseadas para el hormigón fue de 1.10-2.00 árido fino / cemento, 1.90-2.90 árido grueso / cemento, 0.30-0.4 agua / cemento y 0.01-0.013 aditivos químicos / cemento. Ambos métodos tuvieron más del 94% de precisión, en comparación con los resultados experimentales. Finalmente, al emplear los métodos RSM y PSO, el número de mezclas experimentales probadas podría reducirse, ahorrando tiempo y dinero, así como disminuyendo las emisiones de CO2
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