1,023 research outputs found
Use of Biomass From Reed Canary Grass (Phalaris Arundinacea) as Raw Material for Production of Paper Pulp and Fuel
Reed canary grass (Phalaris arundinacea) has been investigated as a potential industrial crop in Sweden and other European countries. Reed canary grass (RCG) can be used as raw-material for paper pulp or as biofuel for combustion. A new harvest method, the delayed harvesting system, was developed which makes it possible to get dry, ready to store, material. The method reduces cost and improves quality of the product. The use of RCG as an industrial crop requires a completely different quality compared to forage. The important part is the cellulose while protein and mineral nutrients are disturbing the process both as a fuel and in fibre production. Different botanical parts of the plant have different quality; it is possible to further improve quality by fractionating and processing. So far all experiments have been conducted with varieties of RCG developed for forage use. A plant breeding programme has been started aiming at varieties suitable for the new area
Coupling Control Variates for Markov Chain Monte Carlo
We show that Markov couplings can be used to improve the accuracy of Markov
chain Monte Carlo calculations in some situations where the steady-state
probability distribution is not explicitly known. The technique generalizes the
notion of control variates from classical Monte Carlo integration. We
illustrate it using two models of nonequilibrium transport
The Partisan Politics of New Social Risks in Advanced Postindustrial Democracies: Social Protection for Labor Market Outsiders
Advanced postindustrialization generates numerous challenges for the European social model. Central among these challenges is declining income, unstable employment, and inadequate training of semi- and unskilled workers. In this chapter, I assess the partisan basis of support for social policies that address the needs of these marginalized workers. I specifically consider the impacts of postindustrial cleavages among core constituencies of social democratic parties on the capacity of these parties to pursue inclusive social policies. I argue – and find support for in empirical analyses – that encompassing labor organization is the most important factor in strengthening the ability of left parties to build successful coalitions in support of outsider-friendly policies. I go beyond existing work on the topic by considering the full array of postindustrial cleavages facing left parties, by more fully elaborating why encompassing labor organization is crucial, and by considering a more complete set of measures of outsider policies than extant work. I compare my arguments and findings to important new work that stresses coalition building and partisan politics but minimizes the role of class organization
Scaling Limits for Internal Aggregation Models with Multiple Sources
We study the scaling limits of three different aggregation models on Z^d:
internal DLA, in which particles perform random walks until reaching an
unoccupied site; the rotor-router model, in which particles perform
deterministic analogues of random walks; and the divisible sandpile, in which
each site distributes its excess mass equally among its neighbors. As the
lattice spacing tends to zero, all three models are found to have the same
scaling limit, which we describe as the solution to a certain PDE free boundary
problem in R^d. In particular, internal DLA has a deterministic scaling limit.
We find that the scaling limits are quadrature domains, which have arisen
independently in many fields such as potential theory and fluid dynamics. Our
results apply both to the case of multiple point sources and to the
Diaconis-Fulton smash sum of domains.Comment: 74 pages, 4 figures, to appear in J. d'Analyse Math. Main changes in
v2: added "least action principle" (Lemma 3.2); small corrections in section
4, and corrected the proof of Lemma 5.3 (Lemma 5.4 in the new version);
expanded section 6.
Colloid-Facilitated Radionuclide Transport in Fractured Carbonate Rock from Yucca Flat, Nevada National Security Site
Evaluation of a Sr+ 88 Optical Clock with a Direct Measurement of the Blackbody Radiation Shift and Determination of the Clock Frequency
We report on an evaluation of an optical clock that uses the S21/2→D25/2 transition of a single Sr+88 ion as the reference. In contrast to previous work, we estimate the effective temperature of the blackbody radiation that shifts the reference transition directly during operation from the corresponding frequency shift and the well-characterized sensitivity to thermal radiation. We measure the clock output frequency against an independent Yb+171 ion clock, based on the S21/2(F=0)→F27/2(F=3) electric octupole (E3) transition, and determine the frequency ratio with a total fractional uncertainty of 2.3×10-17. Relying on a previous measurement of the Yb+171 (E3) clock frequency, we find the absolute frequency of the Sr+88 clock transition to be 444 779 044 095 485.277(59) Hz. Our result reduces the uncertainty by a factor of 3 compared with the previously most accurate measurement and may help to resolve so far inconsistent determinations of this value. We also show that for three simultaneously interrogated Sr+88 ions, the increased number causes the expected improvement of the short-term frequency instability of the optical clock without degrading its systematic uncertainty
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