Review: nanoparticles and nanostructured materials in papermaking

The introduction of nanoparticles (NPs) and nanostructured materials (NSMs) in papermaking originally emerged from the perspective of improving processing operations and reducing material consumption. However, a very broad range of nanomaterials (NMs) can be incorporated into the paper structure and allows creating paper products with novel properties. This review is of interdisciplinary nature, addressing the emerging area of nanotechnology in papermaking focusing on resources, chemical synthesis and processing, colloidal properties, and deposition methods. An overview of different NMs used in papermaking together with their intrinsic properties and a link to possible applications is presented from a chemical point of view. After a brief introduction on NMs classification and papermaking, their role as additives or pigments in the paper structure is described. The different compositions and morphologies of NMs and NSMs are included, based on wood components, inorganic, organic, carbon-based, and composite NPs. In a first approach, nanopaper substrates are made from fibrillary NPs, including cellulose-based or carbon-based NMs. In a second approach, the NPs can be added to a regular wood pulp as nanofillers or used in coating compositions as nanopigments. The most important processing steps for NMs in papermaking are illustrated including the internal filling of fiber lumen, LbL deposition or fiber wall modification, with important advances in the field on the in situ deposition of NPs on the paper fibers. Usually, the manufacture of products with advanced functionality is associated with complex processes and hazardous materials. A key to success is in understanding how the NMs, cellulose matrix, functional additives, and processes all interact to provide the intended paper functionality while reducing materials waste and keeping the processes simple and energy efficient.     

How Small Is a Point Load? A Preliminary Study of the Deformation and Failure of Cartons Subjected to Non‐Uniform Loads

Consumer packaging made from carton board is subjected to a variety of loads as it moves through the value chain. Packaging designers need tools for predicting the strength of packages under these loading conditions. For evenly distributed loads, there are methods for measuring and estimating compression resistance that can provide useful guidance. For loads concentrated to a small area, little work has been published. The aim of this preliminary study is to aid the development of a future test method for point loads by investigating how the size of the load application site influences the mechanical behaviour of the package. Rigid spheres of a range of sizes were used to compress packages. Small spheres gave rise primary damage in the form of a vertical yield line and secondary damage in the form of a parabolic yield line. Larger spheres produced a series of parabolic yield lines of increasing size. No vertical yield line appeared for the larger spheres. The larger spheres showed a stiffness transition at a displacement that could be estimated by considering the geometry of the test. Copyright © 2017 John Wiley & Sons, Ltd.     

Correction to: The J-area integral applied in peridynamics

International Journal of Fracture - The original online version of this article was revised because of errors made in the production process regarding the lay out.     

Relationship between microstructure and bowing properties of calcite marble claddings

The use of thin (20–40 mm) marble as cladding for building facades has increased substantially during the last few decades. Many of the marble facades perform but some durability problems have occurred, especially with calcite marble, when the cladding starts to bow indicating a decrease in strength. This study considers the influence of the microstructure on the bowing of the calcite marble using adjacent grains analysis. Samples with a granoblastic texture all had six adjacent grains while those with a more complex microstructure had up to 13 adjacent grains. The samples with a granoblastic texture had the greatest degree of bowing, suggesting that the microstructure is a crucial parameter for the durability of marble and that adjacent grains analysis could be a fast and easy method to assess the suitability of marble for cladding purposes.     

Foraging for identity: the relationships between landscape activities and landscape identity after catastrophic landscape change

ABSTRACT

In this article, we deal with landscape activities in relation to changing landscape identity after a major wildfire in Sweden in 2014. The aim was to investigate the relationships between 22 landscape activities (before the fire) and 2 components (emotion and cognition) of landscape identity (before and after the fire). A total of 656 respondents living nearby the fire area participated in this study. Before the fire, a positive association was found between the activities of enjoying nature and foraging, and both components of landscape identity. This suggests that the more participants enjoyed nature and picked berries and mushrooms, the stronger their attachment to the landscape (emotion), and the more they remembered and reasoned about the landscape (cognition). Post fire, these relationships were found only between the two components of landscape identity and foraging. This implies a significant role of this type of activity for keeping ‘alive’ landscape identity.     

Interregional allocation models of infrastructure investments

This paper deals with the allocation of public investments to some of the prospective key elements in the regional infrastructure. Two optimization models are suggested for allocating investment resources among regions and various infrastructure elements. Applications of the models illustrate solutions based on policy goals of economic efficiency and regional equity. The optimization models draw on the estimation of an aggregate regional production function.     

Amperometric response from the glycolytic versus the pentose phosphate pathway in Saccharomyces cerevisiae cells

The two main metabolic pathways involved in sugar metabolism, i.e., the pentose phosphate pathway (PPP) and the glycolytic pathway (GP), were amperometrically monitored using a double-mediator system composed of menadione and ferricyanide. With the use of the Saccharomyces cerevisiae deletion mutant, EBY44, lacking the gene encoding for the branch point enzyme phosphoglucose isomerize, selective amperometric monitoring of the PPP, mainly producing NADPH, and the GP, mainly producing NADH, could be achieved. It was found that the bioelectrocatalytic current was primarily originating from NADPH. This conclusion was supported by metabolite flux analysis, confirming that, in the presence of menadione, the cells increase the rate of NADPH-producing reactions although these processes might be detrimental to cell survival. The higher rate of in vivo NADPH-dependent menadione reduction can be ascribed to the fact that the intracellular NADPH/NADP(+) ratio is much higher than NADH/NAD(+) as well as that the former ratio is more tightly controlled. This tight control over the cofactor ratios is lost upon cell disintegration as observed from spectrophotometric assays using crude cell extract, and amperometric investigations of permeabilized cells indicate a higher rate of NADH- than NADPH-dependent menadione reduction. These in vitro experiments show a higher activity of NADH-dependent than NADPH-dependent menadione-reducing dehydrogenases in S. cerevisiae cells.     

Use of local grid refinement and a Galerkin technique to study secondary migration in fractured and faulted regions

A simulator, which includes a full three dimensional, multi-component and three phase model for secondary oil migration is used to study flow through fractured and faulted regions. A control volume discretization is used to discretize the strongly coupled system of partial differential equations the model creates. Non-regular and non-matching local grid refinement (LGR) is used in critical areas to ensure the required accuracy. Two solution methods for solving the composite problem LGR create are studied. The simplest one uses the GMRES solver directly on the composite problem. The second method splits the composite problem into one coarse problem and one problem for each refined area. This method is a two level multigrid method which is based on a Galerkin technique. The CPU time and the number of iteration needed for convergence in both methods are presented and compared. Received: 23 February 1999 / Accepted: 17 June 1999