559 research outputs found

    TB82: The Potential of Softwood Thinnings and Standing Dead Softwoods as a Source of Wood Pulp

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    This study was made to determine the potential of softwood thinnings and standing dead softwood as a source of wood pulp, employing the kraft process. In the thinning studies examined eastern white pine, eastern hemlock, balsam fir, norway spruce, red pine, eastern larch, and northern white cedar. The stem (wood and bark) and the top (wood, bark, and needles) and the stem and top combined were pulped. When compared with pulp from a commercial-size softwood species, the thinnings provided pulps of good strength that were slightly undercooked and that had significantly lower yields. The stem portion pulps were superior in all cases to those made from the top portion. This is attributed to the foliage and higher bark content of the branches of the top which resulted in relatively low yields. The brief study of the characteristics of standing dead softwood trees, either killed by fire or natural attrition, indicated that they compare favorably with the live thinnings as a source of pulp when yield and physical properties are the criteria. It was concluded from this study that 35-4 0 percent of the thinnings material is available as a good grade of wood pulp.https://digitalcommons.library.umaine.edu/aes_techbulletin/1111/thumbnail.jp

    TB17: Fiber Weight and Pulping Characteristics of the Logging Residue of Seven Tree Species in Maine

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    This publication presents information on fiber weight and pulping characteristics of the logging residue of red spruce, red maple, white birch, white pine, balsam fir, hemlock, and aspen. The accumulation of evidence concerning the amount of fiber in the present logging residue and the pulping potential of that residue justifies this synthesis of the various studies in a single publication.https://digitalcommons.library.umaine.edu/aes_techbulletin/1177/thumbnail.jp

    Efficient feedback controllers for continuous-time quantum error correction

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    We present an efficient approach to continuous-time quantum error correction that extends the low-dimensional quantum filtering methodology developed by van Handel and Mabuchi [quant-ph/0511221 (2005)] to include error recovery operations in the form of real-time quantum feedback. We expect this paradigm to be useful for systems in which error recovery operations cannot be applied instantaneously. While we could not find an exact low-dimensional filter that combined both continuous syndrome measurement and a feedback Hamiltonian appropriate for error recovery, we developed an approximate reduced-dimensional model to do so. Simulations of the five-qubit code subjected to the symmetric depolarizing channel suggests that error correction based on our approximate filter performs essentially identically to correction based on an exact quantum dynamical model

    The Commercial Use of Puckerbrush Pulp

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    This study investigates the potential of several local puckerbrush or weed trees and shrubs as sources of fiber for papermaking. Four different pulping processes were used (sulfate, magnesium bisulfite, neutral sulfite semichemical, and cold caustic) with six puckerbrush species (alder, gray birch, red maple, pin cherry, aspen, and willow). Mixtures of puckerbrush species, and commercial chip-puckerbrush species mixtures were pulped by the sulfate process with the objective of producing a pulp that would be suitable for fine-grade papers. The results produced a good grade of bleachable pulp with adequate physical characteristics for most fine paper grades. The other three pulping processes were used to produce higher yield pulps suitable for coarse grades of paper and paperboard. The magnesium bisulfite process produced a pulp in the 50 percent yield category but did not adequately pulp the bark. The neutral sulfite semichemical process gave a relatively high yield of a pulp that compared favorably to commercial pulps used in the manufacture of corrugating board. The cold caustic pulping process resulted in high yields of a pulp that had many of the characteristics of pulp from commercial hardwood chips.https://digitalcommons.library.umaine.edu/aes_techbulletin/1138/thumbnail.jp

    TB65: The Commercial Use of Puckerbrush Pulp

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    This study investigates the potential of several local puckerbrush or weed trees and shrubs as sources of fiber for papermaking. Four different pulping processes were used (sulfate, magnesium bisulfite, neutral sulfite semichemical, and cold caustic) with six puckerbrush species (alder, gray birch, red maple, pin cherry, aspen, and willow). Mixtures of puckerbrush species, and commercial chip-puckerbrush species mixtures were pulped by the sulfate process with the objective of producing a pulp that would be suitable for fine-grade papers. The results produced a good grade of bleachable pulp with adequate physical characteristics for most fine paper grades. The other three pulping processes were used to produce higher yield pulps suitable for coarse grades of paper and paperboard. The magnesium bisulfite process produced a pulp in the 50 percent yield category but did not adequately pulp the bark. The neutral sulfite semichemical process gave a relatively high yield of a pulp that compared favorably to commercial pulps used in the manufacture of corrugating board. The cold caustic pulping process resulted in high yields of a pulp that had many of the characteristics of pulp from commercial hardwood chips.https://digitalcommons.library.umaine.edu/aes_techbulletin/1138/thumbnail.jp

    TB49: Puckerbrush Pulping Studies

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    A study was made of the potential of weed trees and shrubs, called puckerbrush, native to the state of Maine as a source of fiber for the paper industry. Six species—gray birch, red maple, pin cherry, aspen, alder, and willow—were used in the study. All components of each species were studied separately, including stemwood, branches, roots, and stump. In addition, two mixtures of components of each species were studied: Composite 1, a representative mixture of stem, branches, roots and stump, and Composite 2, a mixture of stem and branches.https://digitalcommons.library.umaine.edu/aes_techbulletin/1144/thumbnail.jp

    Density Estimation and Wavelet Thresholding via Bayesian Methods: A Wavelet Probability Band and Related Metrics Approach to Assess Agitation and Sedation in ICU Patients

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    A wave is usually defined as an oscillating function that is localized in both time and frequency. A wavelet is a “small wave”, which has its energy concentrated in time providing a tool for the analysis of transient, non-stationary, or time-varying phenomena. Wavelets have the ability to allow simultaneous time and frequency analysis via a flexible mathematical foundation. Wavelets are well suited to the analysis of transient signals in particular. The localizing property of wavelets allows a wavelet expansion of a transient component on an orthogonal basis to be modelled using a small number of wavelet coefficients using a low pass filter. This wavelet paradigm has been applied in a wide range of fields, such as signal processing, data compression and image analysis

    Wavelet Signatures and Diagnostics for the Assessment of ICU Agitation-Sedation Protocols

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    The use of quantitative modelling to enhance understanding of the agitation-sedation (A-S) system and the provision of an A-S simulation platform are key tools in this area of patient critical care. A suite of wavelet techniques and metrics based on the discrete wavelet transform (DWT) are developed in this chapter which are shown to successfully establish the validity of deterministic agitation-sedation (A-S) models against empirical (recorded) dynamic A-S infusion profiles. The DWT approach is shown to provide robust performance metrics of A-S control and also yield excellent visual assessment tools. This approach is generalisable to any study which investigates the similarity or closeness of bivariate time series of, say, a large number of units (patients, households etc) and of disparate lengths and of possibly extremely long length. This work demonstrates the value of the DWT for assessing ICU agitation-sedation deterministic models, and suggests new wavelet based diagnostics by which to assess the A-S models
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