1. Slot‑die coating of cellulose nanocrystals and chitosan for improved barrier properties of paperYlenia Ruberto, Vera Vivod, Janja Juhant Grkman, Gregor Lavrič, Claudia Graiff, Vanja Kokol, 2024, original scientific article Abstract: Cellulose nanocrystals (CNCs) and chitosan (Cht) have been studied extensively for oxygen and water vapour barrier coatings in biodegradable, compostable or recyclable paper packaging. However, rare studies have been performed by using scalable, inexpensive, and fast continuous slot-die coating processes, and none yet in combination with fast' and high-throughput near-infrared (NIR) light energy drying. In this frame, we studied the feasibility of a moderately concentrated (11 wt%) anionic CNC and (2 wt%) cationic Cht coating (both containing 20 wt% sorbitol related to the weight of CNC/Cht), by using plain and pigment pre-treated papers. The effect of coating parameters (injection speed, dry thickness settings) were investigated on coating quantity (dry weight, thickness) and homogeneity (coverage), papers' structure (thickness, grammage, density), whiteness, surface wettability, barrier (air, oxygen and water vapour) properties and adhesion (surface strength). The coating homogeneity was dependent primarily on the suspensions' viscosity, and secondarily on the applied coating parameters, whereby CNCs could be applied at 1–2 times higher injection speeds (up to 80 mL/min) and versatile coating weights, but required a relatively longer time to dry. The CNCs thus exhibited outstanding air (4.2–1.5 nm/Pa s) and oxygen (2.7–1.1 cm3 mm/m2 d kPa) barrier performance at 50% RH and 22–33 g/m2 deposition, whereas on top deposited Cht (3–4 g/m2) reduced its wetting time and improved the water vapour barrier (0.23–0.28 g mm/m2 d Pa). The balanced barrier properties were achieved due to the polar characteristic of CNCs, the hydrophobic nature of Cht and the quantity of the applied bilayer coating that can provide sustainable paper-based packaging.
Keywords: paper, nanocellulose, chitosan, slot‑die coating, near-infrared (NIR) drying, barrier properties
Published in DKUM: 06.05.2024; Views: 227; Downloads: 11
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3. Culture change in construction industry: from 2D toward BIM based construction : geometric data exchange using the IFC standardNenad Čuš Babič, Danijel Rebolj, 2016, original scientific article Abstract: Building Information Modelling (BIM) has become accepted as an approach that should deliver substantial gains to all the stakeholders within the architecture, engineering and construction (AEC) industry. Recently, several researchers have pointed out the need for cultural changes as a necessary step for radically transforming the industry. In order to provide answers to these requests, the culture should be described in a more explicit way, and industry issues interpreted correctly. This paper via qualitative research of variety of sources explores the stability and persistence of a traditional 2D paper-based approach in the light of Institutional theory. The paper illustrates how the traditional approach is embedded within AEC culture by considering the regulative, normative, and cultural-cognitive aspects. These aspects support each other, thus providing even more stability and support for the existing values and ways of working. The aim of this work is to provide some insight into reasons for slower penetration of the BIM based construction. The paper also explains the local character of the industry, which slows down transference of best practices within the AEC industry. Understanding of existing patterns reveals new insights into how to make the transition easier and more functional, especially within the contexts of existing priorities and values.
Keywords: building information modelling, BIM, institutional theory, 2D paper based working
Published in DKUM: 07.08.2017; Views: 1435; Downloads: 115
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4. Biodiversity in models of cyclic dominance is preserved by heterogeneity in site-specific invasion ratesAttila Szolnoki, Matjaž Perc, 2016, original scientific article Abstract: Global, population-wide oscillations in models of cyclic dominance may result in the collapse of biodiversity due to the accidental extinction of one species in the loop. Previous research has shown that such oscillations can emerge if the interaction network has small-world properties, and more generally, because of long-range interactions among individuals or because of mobility. But although these features are all common in nature, global oscillations are rarely observed in actual biological systems. This begets the question what is the missing ingredient that would prevent local oscillations to synchronize across the population to form global oscillations. Here we show that, although heterogeneous species-specific invasion rates fail to have a noticeable impact on species coexistence, randomness in site-specific invasion rates successfully hinders the emergence of global oscillations and thus preserves biodiversity. Our model takes into account that the environment is often not uniform but rather spatially heterogeneous, which may influence the success of microscopic dynamics locally. This prevents the synchronization of locally emerging oscillations, and ultimately results in a phenomenon where one type of randomness is used to mitigate the adverse effects of other types of randomness in the system.
Keywords: biodiversity, cyclic dominance, rock-paper-scissors, physics of social systems
Published in DKUM: 23.06.2017; Views: 1164; Downloads: 342
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