A Comparison of the Methods Used to Produce Water-Resistant Starch Coatings

Part I Literature Survey The use of the starch in the coating of paper has been very extensive. The reason being that starch and its conversion products have most of the desirable characteristics of a coating adhesive and are relatively inexpensive. Only one main characteristic is missing in coatings made with starch and that is the lack of water resistance. For many years the paper industry, the adhesive industry, and the textile industry have searched for a method of modifying starch so as to increase its water resistance. A great many processes have developed from these studies. These processes consist of blocking the hydroxyl group of the starch by the use of cross linkage or by the use of a protective water resistant substance either over or mixed through the starch. This is achieved by the use of antimony salts (8, 12, 13), urea formaldehyde resins (6, 7, 9, 12, 15, 21, 22, 29, 33), formaldehyde (23, 24, 2, 27), melamino formaldehyde resins (10, 28, 34), phenol formaldehyde resins (25), chronic salts (4, 5, 16, 17, 18), silicates (1), estor gum emulsion (11), polyvinyl alcohols (30, 31), nitro cellulose (3), latices (32), and various synthetic resins (26). These methods vary in ease of application and results accomplished. There are many other methods of water proofing starch but most of them are not applicable to starch coatings

Quantitative estimation of localization errors of 3 d transition metal pseudopotentials in diffusion Monte Carlo

The necessarily approximate evaluation of non-local pseudopotentials in diffusion Monte Carlo (DMC) introduces localization errors. We estimate these errors for two families of non-local pseudopotentials for the first-row transition metal atoms Sc-Zn using an extrapolation scheme and multideterminant wavefunctions. Sensitivities of the error in the DMC energies to the Jastrow factor are used to estimate the quality of two sets of pseudopotentials with respect to locality error reduction. The locality approximation and T-moves scheme are also compared for accuracy of total energies. After estimating the removal of the locality and T-moves errors, we present the range of fixed-node energies between a single determinant description and a full valence multideterminant complete active space expansion. The results for these pseudopotentials agree with previous findings that the locality approximation is less sensitive to changes in the Jastrow than T-moves yielding more accurate total energies, however not necessarily more accurate energy differences. For both the locality approximation and T-moves, we find decreasing Jastrow sensitivity moving left to right across the series Sc-Zn. The recently generated pseudopotentials of Krogel et al. [Phys. Rev. B 93, 075143 (2016)] reduce the magnitude of the locality error compared with the pseudopotentials of Burkatzki et al. [J. Chem. Phys. 129, 164115 (2008)] by an average estimated 40% using the locality approximation. The estimated locality error is equivalent for both sets of pseudopotentials when T-moves is used. For the Sc-Zn atomic series with these pseudopotentials, and using up to three-body Jastrow factors, our results suggest that the fixed-node error is dominant over the locality error when a single determinant is used

Ab initio quantum Monte Carlo calculations of spin superexchange in cuprates: the benchmarking case of Ca2_2CuO3_3

In view of the continuous theoretical efforts aimed at an accurate microscopic description of the strongly correlated transition metal oxides and related materials, we show that with continuum quantum Monte Carlo (QMC) calculations it is possible to obtain the value of the spin superexchange coupling constant of a copper oxide in a quantitatively excellent agreement with experiment. The variational nature of the QMC total energy allows us to identify the best trial wave function out of the available pool of wave functions, which makes the approach essentially free from adjustable parameters and thus truly ab initio. The present results on magnetic interactions suggest that QMC is capable of accurately describing ground state properties of strongly correlated materials.Comment: Published in Physical Review

Constitutional imaginaries : the story of the rise and fall of intellectual enchantment

'What happened to the European Union constitutional imagination?', asks Jan Komárek in the introduction to the book on the European constitutional imaginaries, narratives and utopias. Are the language and metaphors of constitutionalism in the Union still helpful or relevant, and if so, how? This contribution does not read Komárek's question as concerning the (nostalgia-generative) demise of constitutional vocabulary. Rather, this paper modestly suggests a response to the abovementioned question. It does so by looking at the material, socio-economic conditions of the European constitutional academia and scholarship. I believe that such a perspective can quite easily fit the book's sensitivity to the political-economic layer of law. Before moving on to the argument, two caveats should be highlighted. First, the paper does not make any claim to giving an exclusive and final response. Instead, it suggests that, apart from exploring the political economy or socio-economic philosophy of the EU, it is also worth seeking explanations a bit closer, in the material preconditions of the academic profession itself. Second, the paper is not driven by the wish to save or to praise the grand (or at least large enough) constitutional narratives for their own sake. Rather, it assumes that at least some of the constitutional imaginaries have had refreshing, enchanting, inspiring and emancipatory potential. It is this potential that, I argue, can serve as an explanatory tool for tracing the transformation of the European constitutional imaginaries