7,411 research outputs found

    The Effect of Fines on the Surface Characteristics of Recycled Paper

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    With the steady increase in recycling comes an increasing need to understand the mechanisms involved with reused wood fibers. The purpose of this experiment is to determine the effects of fines on the surface characteristics of recycled paper, and to predict how an increase or decrease in fines loading might affect printing. To meet these objectives, fines were removed from both virgin pulp and mill broke of similar composition. Each fines fraction was then reapplied to each long fraction at 0, 5, 10, and 15 percent loading by weight. British handsheets were made and evaluated for surface strength, absorbency, smoothness, and optical properties. Fines from recycled stock were shown to be much less active than fines for virgin stock. Increasing recycled fines showed only a very slight improvement in surface strength, a reduction in liquid penetration, increased scattering/opacity, and slightly decreased brightness. No conclusions could be made for effects on smoothness. These results indicate that increased recycled fines would increase hold out and reduce ink penetration and ink show through. Overall, with the exception of opacity, fines appear to play a much smaller role in paper making when the paper is recycled

    Channeling 5-min photospheric oscillations into the solar outer atmosphere through small-scale vertical magnetic flux tubes

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    We report two-dimensional MHD simulations which demonstrate that photospheric 5-min oscillations can leak into the chromosphere inside small-scale vertical magnetic flux tubes. The results of our numerical experiments are compatible with those inferred from simultaneous spectropolarimetric observations of the photosphere and chromosphere obtained with the Tenerife Infrared Polarimeter (TIP) at 10830 A. We conclude that the efficiency of energy exchange by radiation in the solar photosphere can lead to a significant reduction of the cut-off frequency and may allow for the propagation of the 5 minutes waves vertically into the chromosphere.Comment: accepted by ApJ

    Team leadership : core competencies in children\u27s ministries

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    https://place.asburyseminary.edu/ecommonsatsdissertations/2470/thumbnail.jp

    Pattern formation during diffusion limited transformations in solids

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    We develop a description of diffusion limited growth in solid-solid transformations, which are strongly influenced by elastic effects. Density differences and structural transformations provoke stresses at interfaces, which affect the phase equilibrium conditions. We formulate equations for the interface kinetics similar to dendritic growth and study the growth of a stable phase from a metastable solid in both a channel geometry and in free space. We perform sharp interface calculations based on Green's function methods and phase field simulations, supplemented by analytical investigations. For pure dilatational transformations we find a single growing finger with symmetry breaking at higher driving forces, whereas for shear transformations the emergence of twin structures can be favorable. We predict the steady state shapes and propagation velocities, which can be higher than in conventional dendritic growth.Comment: submitted to Philosophical Magazin

    Mode I crack tip fields: Strain gradient plasticity theory versus J2 flow theory

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    The mode I crack tip asymptotic response of a solid characterised by strain gradient plasticity is investigated. It is found that elastic strains dominate plastic strains near the crack tip, and thus the Cauchy stress and the strain state are given asymptotically by the elastic K-field. This crack tip elastic zone is embedded within an annular elasto-plastic zone. This feature is predicted by both a crack tip asymptotic analysis and a finite element computation. When small scale yielding applies, three distinct regimes exist: an outer elastic K field, an intermediate elasto-plastic field, and an inner elastic K field. The inner elastic core significantly influences the crack opening profile. Crack tip plasticity is suppressed when the material length scale \ell of the gradient theory is on the order of the plastic zone size estimation, as dictated by the remote stress intensity factor. A generalized J-integral for strain gradient plasticity is stated and used to characterise the asymptotic response ahead of a short crack. Finite element analysis of a cracked three point bend specimen reveals that the crack tip elastic zone persists in the presence of bulk plasticity and an outer J-field

    Crack growth resistance in metallic alloys: The role of isotropic versus kinematic hardening

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    The sensitivity of crack growth resistance to the choice of isotropic or kinematic hardening is investigated. Monotonic mode I crack advance under small scale yielding conditions is modelled via a cohesive zone formulation endowed with a traction-separation law. R-curves are computed for materials that exhibit linear or power law hardening. Kinematic hardening leads to an enhanced crack growth resistance relative to isotropic hardening. Moreover, kinematic hardening requires greater crack extension to achieve the steady state. These differences are traced to the non-proportional loading of material elements near the crack tip as the crack advances. The sensitivity of the R-curve to the cohesive zone properties and to the level of material strain hardening is explored for both isotropic and kinematic hardening

    Transcendental Thermodynamics

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    Thermodynamics is often viewed as a narrow, introspective discipline, trapped by its origins in the 18th and 19th centuries. By dramatic contrast, we show that the Fourth Law of Thermodynamics provides explanations and interpretations of all natural events, extending across artificial boundaries of tradition- al academic disciplines. The Fourth Law of Thermodynamics states that far-from-equilibrium systems increase entropy at the maximum rate available to them. This broadly inclusive paradigm applies to systems from molecules, to organisms, to the biosphere. The Fourth Law is the Law of Evolution. All systems that communicate with their environment exhibit self-organization and self-optimization, enabling the emergence and the evolution of life as a sustained optimization of entropy increase

    Analyzing and Predicting Verification of Data-Aware Process Models – a Case Study with Spectrum Auctions

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    Verification techniques play an essential role in detecting undesirable behaviors in many applications like spectrum auctions. By verifying an auction design, one can detect the least favorable outcomes, e.g., the lowest revenue of an auctioneer. However, verification may be infeasible in practice, given the vast size of the state space on the one hand and the large number of properties to be verified on the other hand. To overcome this challenge, we leverage machine-learning techniques. In particular, we create a dataset by verifying properties of a spectrum auction first. Second, we use this dataset to analyze and predict outcomes of the auction and characteristics of the verification procedure. To evaluate the usefulness of machine learning in the given scenario, we consider prediction quality and feature importance. In our experiments, we observe that prediction models can capture relationships in our dataset well, though one needs to be careful to obtain a representative and sufficiently large training dataset. While the focus of this article is on a specific verification scenario, our analysis approach is general and can be adapted to other domains

    “It’s the story”: Online Animated Simulation of Cultural Competence of Poverty -- A Pilot Study

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    Purpose: In this pilot study, researchers explore an online animated simulation as an educational tool for emerging health professionals to promote cultural competence of poverty, food insecurity, and the Supplemental Nutrition Assistance Program.Methods: Researchers recruited participants in the allied health sciences for focus groups to explore the effectiveness of an online animation in promoting cultural competence of poverty, food insecurity, and public assistance programs. Participants were asked about their experience with the educational tool and changes in cultural competence regarding poverty, food insecurity, and the Supplemental Nutrition Assistance Program. Participants also responded to five survey questions about their experience of the educational tool and cultural competence of poverty. Transcripts from focus groups were coded according to the five constructs of the Campinha-Bacote model for cultural competence, and further coded for recurring themes within these constructs. Results: Eleven participants across four allied health professions including nutrition, occupational therapy, nursing and pre-physical therapy participated in two focus groups. Researchers found all five constructs of the Campinha-Bacote model in analysis of focus group transcripts, with awareness and desire expressed more frequently and intensely. Participants stated the animated simulation increased their empathy for people who experience poverty, food insecurity and who need public assistance programs. Conclusion: Researchers find that this online animated simulation was an effective tool to improve cultural competence of poverty for emerging healthcare professionals. Use of similar animations by educators of healthcare professionals may also change existing negative views towards those who rely on the Supplemental Nutrition Assistance Program benefits and reduce the barrier of stigma associated with the program
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