Percolation Theory

Cellulose nanocrystals (CNCs) were isolated from soy hulls by acid sulfuric hydrolysis. The resulting CNCs were characterized using TEM, AFM, WAXS, elemental analysis and TGA. The CNCs have a high crystallinity, specific surface area and aspect ratio. The aspect ratio (around 100) is the largest ever reported in the literature for a plant cellulose source. These CNCs were used as a reinforcing phase to prepare nanocomposite films by casting/evaporation using natural rubber as matrix. The mechanical properties were studied in both the linear and non-linear ranges. The reinforcing effect was higher than the one observed for CNCs extracted from other sources. It may be assigned not only to the high aspect ratio of these CNCs but also to the stiffness of the percolating nanoparticle network formed within the polymer matrix. Moreover, the sedimentation of CNCs during the evaporation step was found to play a crucial role on the mechanical properties.

Soil physics has a dual identity—it is both a branch of physics and a branch of soil science—but its legitimacy as a science depends on its claim to be physics; this implies a self-consistent structure of definitions and concepts underlying the equations we actually use. Upon examining some of our core concepts—specifically those relating the water retention curve to the pore size distribution, the unsaturated hydraulic conductivity relationship, and the
convection–dispersion model—we find that all three are built on the notion that soil is composed of bundles of capillary tubes. This underlying conceptual model lacks both self-consistency (threatening our claim to be a legitimate
science) and a firm connection to reality (threatening our ability to reason and predict successfully). We argue that many of our struggles during the last decades are artifacts of building from the flawed conceptual model of soil as
a capillary bundle. We propose in its place a pore network concept, which can be applied using the mathematics of percolation theory. We must build on a sound and self-consistent conceptual model, in teaching, research, and
application, so soil physics can be firmly based in both soils and physics, and meet society’s many challenges in food production, hydrology, water quality, bio-energy, and climate change.

Abstract. The application of percolation theory to porous media is closely tied to network mod-els. A network model is a detailed model of a porous medium, generally incorporating pore-scale descriptions of the medium and the physics of pore-scale events. Network ...

Experiments have been carried out to study the displacement of wetting fluids by immiscible non-wetting fluids in quasi-two-dimensional and three-dimensional granular porous media. These experiments included a systematic investigation of the effects of gravity acting on the density difference between the two fluids. The simple invasion percolation model provides a surprisingly realistic simulation of the slow fluid–fluid displacement process in

Nowadays, both the business world and the world of academia strongly consider the ability to manage knowledge efficiently as one of the core competences of an organization. Theorists and practitioners especially recognize the importance of knowledge sharing: it is assumed to be one of the key factors of successful knowledge management. Certainly, knowledge itself is widely dispersed in the organization: it is kept by individuals and groups, embedded in their interdependent networks of collaboration and communication including communities of practice, research team memberships, co-publishing, co-inventing, exchanging thoughts and ideas, etc. Nevertheless, building up the process of knowledge sharing from one individual to another or from one department to another still remains a challenge for the majority of organisations. The overarching idea of this paper is to contribute to a better understanding of collective action and to foster collaborative activities within organisations. In this research, the focus lies on studying intra-organisational knowledge sharing. In more detail, we investigate the knowledge interaction network. In doing so, the percolation theory is regarded as the theoretical umbrella. In general, percolation processes result from the interaction of two forces – `connectivityánd`receptivity´. In this study, the first reflects the number of connections between actors in the interaction network, while the second describes the actors' ability to absorb knowledge. The latter force of`receptivityís based on work-related trust among the actors within a given network. This paper refers to leading academic opinions in the literature on Knowledge Management, demonstrating how trust is an essential factor impacting knowledge sharing and that there is a reciprocal effect between social interaction and trust. Following an introduction, this article explores the interrelationship between the concepts of knowledge and trust. The percolation theory is then presented and superimposed onto the knowledge sharing network and a trust-based percolation is modelled. In a further step, using the developed model, a percolation network is built upon empirical data sampled through an email survey completed by the employees and leaders of the financial transaction service departments of an international industry company. We develop our own computer algorithm and calculate the percolation thresholds within the network by combining various characteristics, thereby revealing what influences knowledge sharing. Fundamentally, this paper intends to contribute to the methodology of percolation networks in social sciences, and presents the practical implications of this theory.