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The development of paper-based flexible electronic devices can reduce the use of traditional petroleum-based polymer substrates, thereby reducing environmental pollution. However, paper substrates tend to absorb moisture, which would degrade the performance of electronic devices. Polytetrafluoroethylene (PTFE) films were proposed as coatings for the paper substrate to improve the hydrophobic performance of the paper, thereby enhancing the stability of paper-based device. Hydrophobic PTFE films were deposited on both sides of the paper substrate using electron beam evaporation, which block the paper substrate from absorbing moisture. The zinc oxide (ZnO) film was sputtered onto the paper substrate and fabricated into ultraviolet photodetectors (UVPD). Numerical simulations show that the introduction of PTFE films can greatly reduce the stress from 3.21 × 109 N m−2 to 3.50 × 107 N m−2 in the ZnO epitaxial layer on the paper substrate. The stability and detectivity of the UVPD with PTFE coatings are greatly improved compared to that without PTFE coatings, providing a promising avenue for fabricating stable, superior, and sustainable paper-based electronic devices. [ABSTRACT FROM AUTHOR]

The assessment of the risk of virus transmission through papers, such as postcards, is important. However, the stability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (IAV) on different types of papers is currently unknown. Investigation of the survival time of these viruses on different types of papers will provide insights into their risk of long-distance transport by postal items. We evaluated the stability of SARS-CoV-2 and IAV, mixed with a culture medium, on the surface of postcards with various coatings, including plain paper (PP), inkjet paper (IP), and inkjet photo paper (IPP). The surface structure of each paper was microscopically assessed. The surface structures of PP, IP, and IPP varied greatly depending on the presence or absence, and type, of coat layer, regardless of the base material. IP and IPP surfaces were less conducive to virus survival than PP surfaces, because of the difference in surface shapes. The survival times of SARS-CoV-2 on each paper were approximately 59.8 (PP), 6.5 (IP), and 9.8 h (IPP), and significantly longer than those of IAV (10.3, 1.8, and 3.3 h, respectively). The risk of SARS-CoV-2 transmission via paper, such as postcards, is significantly higher than that of IAV transmission. While PP, IP, and IPP have the same base material, their surface structures differ, which affects viral stability. The IP and IPP surfaces are less suitable for virus survival. This study provides novel insights into the risks of viral transmission via paper. [ABSTRACT FROM AUTHOR]

In this study, a probabilistic analysis of the critical velocity for an axially moving cracked elastic and isotropic plate is presented. Axially moving materials are commonly used in modelling of manufacturing processes, like paper making and plastic forming. In such systems, the most serious threats to runnability are instability and material fracture, and finding the critical value of velocity is essential for efficiency. In this paper, a formula for the critical velocity is derived under constraints for the probabilities of instability and fracture. The significance of randomness in different model parameters is investigated for parameter ranges typical of paper material and paper machines. The results suggest that the most significant factors are variations in the crack length and tension magnitude. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we report on the microencapsulation of glucose oxidase from Aspergillus niger (GOx) and laccase from Trametes versicolor (TvL) with the goal of immobilizing these enzymes in paper substrates to develop biosensors and bioreactors. Despite having high encapsulation efficiency, the technique caused a severe decrease (up to 65%) in the specific activities of both enzymes once microencapsulated. Encapsulated TvL presented lower K M and V max values compared to free laccase in solution, but the K M for GOx did not change after microencapsulation. TvL was found to interact strongly with poly(ethyleneimine) (PEI) in a manner similar to that expected from an uncompetitive inhibition mechanism, and fluorescence and circular dichroism spectroscopy demonstrated that significant alteration of the enzyme''s conformation occurs in the presence of PEI, an effect of the cationic polymer that was not observed with GOx. Microencapsulation improved the thermal stability of GOx at temperatures up to 60°C due to stabilization of its active conformation but reduced the thermal stability of laccase because of the increased coordination between PEI and copper atoms in the enzyme''s active site. Preliminary GOx bioactive paper was fabricated, which could be potentially used as food packaging paper. [Copyright &y& Elsevier]

A one-dimensional model for the analysis of compression of a paper in the printing machine is presented. It is assumed that a paper experiences static compression and the problem of initial stability is solved. A two-dimensional model for the analysis of compression of a paper is described and used for the solution of a similar problem. Also an axi-symmetric model for the analysis of compression of a paper is described and used for the solution of a similar problem. A setup for performing experimental investigations of uniaxial unidirectional symmetrically distributed compression of polymeric film is designed and created. For this purpose the method of digital speckle photography is used. During the investigations the images of the stability eigenmodes of the polymeric film HDPE for uniaxial unidirectional compression of the film were determined. The obtained results are used in the design of the elements of the printing machine. [ABSTRACT FROM AUTHOR]

Abstract: The instability of the tree-like multicast overlay caused by nodes’ abrupt departures is considered as one of the major problems for peer-to-peer (P2P) multicast systems. In this paper, we present a protocol for improving the overlay’s stability by actively estimating the nodes’ lifetime model, and combining the nodes’ lifetime information with the overlay’s structural properties. We use the shifted Pareto distribution to model the nodes’ lifetimes in designing our protocol. To support this model, we have measured the residual lifetimes of the nodes in a popular IPTV system named PPLive [PPLive. http://www.pplive.com], and have formally analyzed the relationships between the distribution of the nodes’ lifetimes, ages and their residual lifetimes under the shifted Pareto distribution model. We evaluate the overlay construction strategies, which are essential in improving the overlay’s stability in our protocol, by comparing them with a number of other strategies in simulation. The experimental results indicate that our proposed protocol could improve the overlay’s stability considerably, with informative but not necessarily accurate lifetime model estimation, and with limited overhead imposed on the network as well as negligible sacrifice regarding the end-to-end service latencies for the nodes on the overlay. [Copyright &y& Elsevier]

Abstract: In this paper, the notion of loss of sustainability of a mechanical state in a granular assembly is investigated. The vanishing of the second-order work, defined on the macroscopic scale from tensorial variables, is shown to play a fundamental role in detecting the occurrence of this type of bifurcation. Then a link is established between the macroscopic second-order work on the specimen scale and a discrete local expression that introduces microscopic variables defined on each contact scale. This relation opens up a micro-mechanical interpretation allowing one to examine which micro-structural features are responsible for the vanishing of the macroscopic second-order work. Finally, it is established that both geometrical and material micro-structural origins may combine to induce the occurrence of bifurcation on a specimen scale. [Copyright &y& Elsevier]

The model for the analysis of vibrations of paper in a printing device is presented. It is assumed that paper performs transverse vibrations as a membrane having stiffness due to static tension in its plane. The first eigenmodes are determined. It is shown that the eigenfrequencies of transverse vibrations of the analyzed paper can be controlled by the static tension in the plane of the paper. The model for the analysis of stability of paper in a printing device is presented. It is assumed that paper moves with constant velocity in a given direction. The analysis is performed using a plate-bending element with the contribution of the forces of inertia from the convective accelerations. This results in the eigenproblem determining the critical velocities and stability eigenmodes. The stand was made for obtaining the experimental investigations. Using it the nodal lines of the standing waves were determined and using projection moiré the eigenmodes were determined. The obtained results are used in the process of design of the elements of the printing device. [ABSTRACT FROM AUTHOR]

Abstract: In the present paper, a description and mathematical analysis of a simple model of nonlinear pattern formation is given. The model is based on the so-called activator-inhibitor system proposed by Thomas. We introduce time delay into the reaction term and focus on its influence on morphogenesis and pattern formation. Numerical simulations are presented and compared for both cases without and with delay. [Copyright &y& Elsevier]

Perovskite quantum dots (PQDs) are a competitive candidate for next‐generation display technologies as a result of their superior photoluminescence, narrow emission, high quantum yield, and color tunability. However, due to poor thermal resistance and instability under high energy radiation, most PQD‐based white light‐emitting diodes (LEDs) show only modest luminous efficiency of ≈50 lm W−1 and a short lifetime of <100 h. In this study, by incorporating cellulose nanocrystals, a new type of QD film is fabricated: CH3NH3PbBr3 PQD paper that features 91% optical absorption, intense green light emission (518 nm), and excellent stability attributed to the complexation effect between the nanocellulose and PQDs. The PQD paper is combined with red K2SiF6:Mn4+ phosphor and blue GaN LED chips to fabricate a high‐performance white LED demonstrating ultrahigh luminous efficiency (124 lm W−1), wide color gamut (123% of National Television System Committee), and long operation lifetime (240 h), which paves the way for advanced lighting technology. [ABSTRACT FROM AUTHOR]