Sustainability challenge on pollution and air quality inside heavy-duty vehicle cabins

Air quality in transportation vehicle cabins is becoming a major concern due to increasing exposure of drivers to harmful gases and aerosol, especially if having in mind that that safety and pollution are positively correlated and adverse events. In order to reduce exposure to air pollution, there is ongoing development of air filters in modern heavy-duty vehicles and increase in protective regulations throughout the world. The aim of this study is to gain insight into extent of pollutants in heavy-duty vehicle cabins, in which drivers spend a large amount of their working (and spare) time, and the necessity for use of air filtration systems. Both experimental results and modelling approach applied in this manuscript reveal the importance of filtration of cabin air, and indicate good correlation between experimental and mathematical results from field measurements conducted in a highly polluted city. Namely, this paper reveals excellent results with the HECA filter which have potential to significantly reduce pollution in the cabin

Heat and mass transfer models to understand the drying mechanisms of a porous substrate

While drying of paper and paper coatings is expensive, with significant energy requirements, the rate controlling mechanisms are not currently fully understood. Two two-dimensional models are used as a first approximation to predict the heat transfer during hot air drying and to evaluate the role of various parameters on the drying rates of porous coatings. The models help determine the structural limiting factors during the drying process, while applying for the first time the recently known values of coating thermal diffusivity. The results indicate that the thermal conductivity of the coating structure is not the controlling factor, but the drying rate is rather determined by the thermal transfer process at the structure surface. This underlines the need for ensuring an efficient thermal transfer from hot air to coating surface during drying, before considering further measures to increase the thermal conductivity of porous coatings

Highly Porous Willow Wood-Derived Activated Carbon for High-Performance Supercapacitor Electrodes

In this study, we present willow wood as a new low-cost, renewable, and sustainable biomass source for the production of a highly porous activated carbon for application in energy storage devices. The obtained activated carbon showed favorable features required for excellent electrochemical performance such as high surface area (∼2 800 m2 g-1) and pore volume (1.45 cm3 g-1), with coexistence of micropores and mesopores. This carbon material was tested as an electrode for supercapacitor application and showed a high specific capacitance of 394 F g-1 at a current density of 1 A g-1 and good cycling stability, retaining ∼94% capacitance after 5000 cycles (at a current density of 5 A g-1) in 6 M KOH electrolyte. The prepared carbon material also showed an excellent rate performance in a symmetrical two-electrode full cell configuration using 1 M Na2SO4 electrolyte, in a high working voltage of 1.8 V. The maximum energy density and power density of the fabricated symmetric cell reach 23 W h kg-1 and 10 000 W kg-1,respectively. These results demonstrate that willow wood can serve as a low-cost carbon feedstock for production of high-performance electrode material for supercapacitors.Peer reviewe

Iceland spar calcite

Understanding the complex and dynamic nature of calcite surfaces under ambient conditions is important for optimizing industrial applications. It is essential to identify processes, their reversibility, and the relevant properties of CaCO3 solid-liquid and solid-gas interfaces under different environmental conditions, such as at increased relative humidity (RH). This work elucidates changes in surface properties on freshly cleaved calcite (topography, wettability and surface forces) as a function of time (≤28 h) at controlled humidity (≤3–95 %RH) and temperature (25.5 °C), evaluated with atomic force microscopy (AFM) and contact angle techniques. In the presence of humidity, the wettability decreased, liquid water capillary forces dominated over van der Waals forces, and surface domains, such as hillocks, height about 7.0 Å, and trenches, depth about −3.5 Å, appeared and grew primarily in lateral dimensions. Hillocks demonstrated lower adhesion and higher deformation in AFM experiments. We propose that the growing surface domains were formed by ion dissolution and diffusion followed by formation of hydrated salt of CaCO3. Upon drying, the height of the hillocks decreased by about 50% suggesting their alteration into dehydrated or less hydrated CaCO3. However, the process was not entirely reversible and crystallization of new domains continued at a reduced rate.Peer reviewe

Surface-Modified and Unmodified Calcite: Effects of Water and Saturated Aqueous Octanoic Acid Droplets on Stability and Saturated Fatty Acid Layer Organization

Funding Information: This work was funded by the Omya International AG. A.S. is a researcher at Pro2BE at the Karlstad University, the research environment on Processes and Products for a Circular Biobased Economy. Publisher Copyright: © 2021 The Authors. Published by American Chemical Society.A profound understanding of the properties of unmodified and saturated fatty acid-modified calcite surfaces is essential for elucidating their resistance and stability in the presence of water droplets. Additional insights can be obtained by also studying the effects of carboxylic acid-saturated aqueous solutions. We elucidate surface wettability, structure, and nanomechanical properties beneath and at the edge of a deposited droplet after its evaporation. When calcite was coated by a highly packed monolayer of stearic acid, a hydrophilic region was found at the three-phase contact line. In atomic force microscopy mapping, this region is characterized by low adhesion and a topographical hillock. The surface that previously was covered by the droplet demonstrated a patchy structure of about 6 nm height, implying stearic acid reorganization into a patchy bilayer-like structure. Our data suggest that during droplet reverse dispensing and droplet evaporation, pinning of the three-phase contact line leads to the transport of dissolved fatty carboxylic acid and possibly calcium bicarbonate Ca(HCO3)2 molecules to the contact line boundary. Compared to the surface of intrinsically hydrophobic materials, such as polystyrene, the changes in contact angle and base diameter during droplet evaporation on stearic acid-modified calcite are strikingly different. This difference is due to stearic acid reorganization on the surface and transport to the water-air interface of the droplet. An effect of the evaporating droplet is also observed on unmodified calcite due to dissolution and recrystallization of the calcite surface in the presence of water. In the case where a water droplet saturated with octanoic acid is used instead of water, the stearic acid-coated calcite remains considerably more stable. Our findings are discussed in terms of the coffee-ring effect.Peer reviewe

Coupling Nanofibril Lateral Size and Residual Lignin to Tailor the Properties of Lignocellulose Films

| openaire: EC/H2020/788489/EU//H2020-EU.1.1.Lignocellulosic nanofibrils (LCNF) are produced from a single source of unbleached, oxidized wood fibers by serial disintegration, high-pressure microfluidization, and homogenization. Sequential centrifugation enables fractionation by fibril width (≈5, ≈9, and ≈18 nm). LCNF residual lignin of high molecular mass reports together with the finest fraction (LCNF-fine), whereas the more strongly cellulose-bound lignin, of relatively lower molecular mass, associates with the coarsest fraction (LCNF-coarse). Hot pressing softens the amorphous lignin, which fills the interstices between fibrils and acts as an in-built interfacial cross-linker. Thus, going from the LCNF-fine to the LCNF-course films, it is possible to obtain a range of values for the structural consolidation (density from 0.9 to 1.2 g cm−3 and porosity from 19% to 40%), surface roughness (RMS from ≈6 to 13 nm), and strength (elastic modulus from 8 to ≈12 GPa). The concentration of free hydroxyl groups controls effectively the direct surface interactions with liquids. The apparent surface energy dispersive component tracks with the total surface free energy and appears to be strongly influenced by the higher porosity as the fibril lateral size increases. The results demonstrate the possibility to tailor nanofibril cross-linking and associated optical and thermo-mechanical performance of LCNF films.Peer reviewe