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Pineapple leaf fibers (PALF) were biopulped using Trametes versicolor, and the resulting biopulp was bleached with xylanase-enzymatic treatments. The biopulping was extensively described using determinations of fiber morphology, color, chemical composition, extractive content, and thermal stability using the structural characteristics determined by XRD and paper properties. The results showed that the chemical and enzymatic treatments shortened the fiber, almost to 50%, and the Kappa index decreased from 27 to 13. Cellulose and holocellulose contents increased from 65% to 74% and from 86% to 91%, respectively, but extractives, lignin (from 12% to 4%), pentosans (from 25% to 14%) and the crystallinity decreased from 58% to 67% in both chemical bleaching and further xylanase-enzymatic processing. Xylanase)enzymatic processing allowed us to obtain whiter (increased lightness color and decreased redness and yellowness tonality) and heavier paper, even though it presented decreased mechanical properties (decreased stress resistance, rupture length, tear resistance and index longitudinal tearing). The xylanase-enzymatic treatment with the best pulping and paper proper)ties is when the biopulp is treated with a xylanase enzyme concentration of 0.04% (w/w). [ABSTRACT FROM AUTHOR]

Banana stem is a known alternative to wood for the production of pulp and paper. During the production of paper, it is extremely important to save costs and time while at the same time enhancing quality of produced paper. In the present study, paper was developed from banana stem fiber by optimizing its density. Response surface methodology (RSM) using Box-Behnken design (BBD) was used to determine optimum blending parameters of the developed papers. The influence of banana stem fiber amount (250-1000 g), water amount (1-2liters) and blending time (5-10 min) on paper density was ana)lyzed using software Stat-Ease 360, Version 13. The optimum conditions of banana stem fiber amount, water amount and blending time to achieve a density of 675.75 g/m3 were determined as 461.83 g, 1.31liters, and 8.53 min, respectively. ANOVA results revealed that the quadratic model best fits the density response, with blending time and banana stem fiber amount as the most significant model terms. Linear effects were more predominant than quadratic and interaction effects. The developed density model was in close agreement with experimental findings with an R² value of 0.9748. Developed paper had cellulosic contents, with volatiles as high as 82.11%wb and 2.11% wb ash composition. Future works on thermal properties of paper are encouraged. [ABSTRACT FROM AUTHOR]

High-performance air filters composed of a hybrid structure of nanofiber/microfiber were fabricated using wet paper processing. Two types of nanofibers (NF) with average diameters of 180 and 234 nm were mixed with a suspension of microfibers (11.5 and 11.7 µm) in various mixing fractions. Then, the suspension was filtered to fabricate hybridized fiber sheets with a known nanofiber/microfiber composition. The effects of NF diameter and mixing fraction on the performance of the hybrid filters were experimentally investigated. With increasing NF fraction, both the particle collection efficiency and the pressure drop increased. The quality factor (Qf) was used to evaluate the performance of the prepared filters. As predicted by the single fiber filtration theory, the experimentally obtained Qf was almost independent of the mixing fraction of the NF. The collection efficiency and pressure drop of the hybrid filters could be controlled by the NF fraction at the same Qf. Moreover, the inhomogeneity factor of fiber packing (δ) did not significantly affect Qf over the δ range from 3 to 23 for our filters. This implies that the lower particle capturing efficiency due to heterogeneous packing could be compensated by a decrease in the pressure drop, resulting in the same Qf value. Therefore, Qf for particles smaller than 100 nm, which are in the diffusion-controlled regime, can be increased by reducing the NF diameter. Copyright © 2019 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

In this review, we summarize the recent progress in thermal conductivity analysis of nanocellulose materials called cellulose nanopapers, and compare them with polymeric materials, including neat polymers, composites, and traditional paper. It is important to individually measure the in-plane and through-plane heat-conducting properties of two-dimensional planar materials, so steady-state and non-equilibrium methods, in particular the laser spot periodic heating radiation thermometry method, are reviewed. The structural dependency of cellulose nanopaper on thermal conduction is described in terms of the crystallite size effect, fibre orientation, and interfacial thermal resistance between fibres and small pores. The novel applications of cellulose as thermally conductive transparent materials and thermal-guiding materials are also discussed. [ABSTRACT FROM AUTHOR]

In this review, we summarize the recent progress in thermal conductivity analysis of nanocellulose materials called cellulose nanopapers, and compare them with polymeric materials, including neat polymers, composites, and traditional paper. It is important to individually measure the in-plane and through-plane heat-conducting properties of two-dimensional planar materials, so steady-state and non-equilibrium methods, in particular the laser spot periodic heating radiation thermometry method, are reviewed. The structural dependency of cellulose nanopaper on thermal conduction is described in terms of the crystallite size effect, fibre orientation, and interfacial thermal resistance between fibres and small pores. The novel applications of cellulose as thermally conductive transparent materials and thermal-guiding materials are also discussed [ABSTRACT FROM AUTHOR]

In this paper, we study the regularity problem of the 3D incompressible Navier–Stokes equations. We prove that the strong solution exists globally for new regularity criteria. For negligible forces, we give an improvement of the known time interval of regularity obtained in [Leray, J. (1933). Etude de diverses équations intégrales non linéaires et de quelques problemes que pose l'hydrodynamique. Journal de Mathmatiques Pures et Appliques 12, 1–82]. [ABSTRACT FROM AUTHOR]

This essay opens out a series of questions concerning matter and materiality in the age of the digital via engagement with the literary papers of Australian writer Eve Langley (1904-74), held in the Mitchell Library in Sydney. Among those papers is a single black and white snapshot labelled 'The Manuscript Cupboard, 1970', which shows three shelves of a household cupboard filled with exercise books, folders and paper-wrapped parcels. The same collection also contains a series of colour snapshots showing Langley's manuscripts arranged in a variety of tableaux laid out across her untended lawn. That Langley should have first taken and then preserved such photos is perhaps not surprising given her deep attachment to material conditions of writing and, in particular, to manuscripts and paper. For Langley, to write was quite simply to inhabit paper and she framed the experience of writing as one of immersion, not just in ideas and words, but literally in paper. Framed by a consideration of the anxieties around materiality provoked by the emergence of digital technologies, this essay explores paper's presence as an integral dimension of the experience of being in the archive and working with original materials. [ABSTRACT FROM AUTHOR]