Topological interactions in a Boltzmann-type framework

We consider a finite number of particles characterised by their positions and velocities. At random times a randomly chosen particle, the follower, adopts the velocity of another particle, the leader. The follower chooses its leader according to the proximity rank of the latter with respect to the former. We study the limit of a system size going to infinity and, under the assumption of propagation of chaos, show that the limit equation is akin to the Boltzmann equation. However, it exhibits a spatial non-locality instead of the classical non-locality in velocity space. This result relies on the approximation properties of Bernstein polynomials

Preparation of breathable cellulose based polymeric membranes with enhanced water resistance for the building industry

This study focuses on the development of advanced water-resistant bio-based membranes with enhanced vapour permeability for use within building envelopes. Building walls are vulnerable to moisture damage and mold growth due to water penetration, built-in moisture, and interstitial condensation. In this work, breathable composite membranes were prepared using micro-fibrillated cellulose fiber (CF) and polylactic acid (PLA). The chemical composition and physical structure of CF is responsible for its hydrophilic nature, which affects its compatibility with polymers and consequently its performance in the presence of excessive moisture conditions. To enhance the dispersibility of CF in the PLA polymer, the fibers were treated with an organic phosphoric acid ester-based surfactant. The hygroscopic properties of the PLA-CF composites were improved after surfactant treatment and the membranes were resistant to water yet permeable to vapor. Morphological examination of the surface showed better interfacial adhesion and enhanced dispersion of CF in the PLA matrix. Thermal analysis revealed that the surfactant treatment of CF enhanced the glass transition temperature and thermal stability of the composite samples. These bio-based membranes have immense potential as durable, eco-friendly, weather resistant barriers for the building industry as they can adapt to varying humidity conditions, thus allowing entrapped water vapor to pass through and escape the building, eventually prolonging the building life

Acrylate Wood Densification: Effects of Vacuum Time and Nanoparticles on Chemical Retention, Penetration, and Resin Distribution

The feasibility of preparing a surface-densified wood product by replacing the traditional time-consuming pressurization stage with only a short vacuum time was investigated. Sugar maple and red oak wood specimens were successfully impregnated with low-viscosity resins of 1,6 hexanediol dimethacrylate and trimethylolpropane trimethacrylate, with or without silicate nanoparticles, using vacuum times of 30 s to 10 min without pressurization. Chemical retention (CR) and vertical density profiles of the treated wood specimens were measured. The CRs obtained with the short vacuum impregnation process, even with a vacuum of 30 s or 60 s, proved comparable to those achieved by the traditional process of 30-min vacuum plus 30-min pressure. A 52-63 wt% CR was found for maple impregnated with neat resin, while the formulations containing nanoparticles achieved 44-55 wt% as the vacuum time was increased 30 s to 10 min. Oak yielded lower CR values. The vertical density profiles indicated better treatability for maple than oak. Examination of the resin and resin/nanoparticle penetration into the wood by scanning electron microscopy revealed successful wood impregnation with both nanoparticles and resin

Trends in chemical wood surface improvements and modifications : a review of the last five years

Increasing the use of wood in buildings is regarded by many as a key solution to tackle climate change. For this reason, a lot of research is carried out to develop new and innovative wood surface improvements and make wood more appealing through features such as increased durability, fire-retardancy, superhydrophobicity, and self-healing. However, in order to have a positive impact on the society, these surface improvements must be applied in real buildings. In this review, the last five years of research in the domain of wood surface improvements and modifications is first presented by sorting the latest innovations into different trends. Afterward, these trends are correlated to specifications representing different normative, ecologic and economic factors which must be considered when expecting to introduce a wood treatment to the market. With this review, the authors hope to help researchers to take into consideration the different factors influencing whether new innovations can leave the research laboratory or not, and thereby facilitate the introduction of new wood surface treatments in the society

Wood productions and renewable materials : the future is now

The forest sector plays a key role in meeting the climate change challenge. Forest products and renewable materials are masterpieces in achieving this role. This editorial destails the benefits of these forest prodcuts and celebrates the contributions of the authors who submitted their work to this special edition of Forests journal. This edition presents 11 papers, which include the characterization of a new fiber supply, the description of advanced materials and their environmental impact, and an examination of structural products, wood protection, and modifications

Effect of Vacuum Time, Formulation, and Nanoparticles on Properties of Surface-Densified Wood Products

Surface-densified wood products were prepared with only a short vacuum impregnation process instead of the traditional time-consuming pressurizing stage. The top layer of engineered wood flooring planks was successfully impregnated with low-viscosity 1,6 hexanediol dimethacrylate and trimethylolpropane trimethacrylate as well as layered silicate nanoparticles by vacuum impregnation of 30 s to 10 min. Treating tests involved two species, maple and oak, and Brinell surface hardness, impact resistance, and abrasion resistance of the treated wood specimens were measured. Brinell surface hardness increased from 5.05-15.42 MPa for maple, the greatest improvement of 205% being obtained with a 30-s vacuum. For oak, Brinell surface hardness increased from 5.25-11.05 MPa with a 60-s vacuum, an improvement of 108%. Impact resistance was based on measurements of indentation diameters and depths in falling ball tests. Decreases in indentation diameters from 4.96-2.84 mm and indentation depths from 0.172-0.034 mm were observed for maple treated with nanoparticle-containing formulations and a 60-s vacuum impregnation, indicating that impact resistance of a one-step, short vacuum impregnation time dramatically improved wood surface hardness. Measurements of abrasion resistance properties of surface-densified specimens were based on specimen weight loss with time following abrasion tests. Weight loss values decreased considerably with treated wood. A factorial experimental design provided information on effects of vacuum time, nanoparticles, and wood species on properties of impregnated wood specimens. Impacts of individual factors and their interactions were analyzed with Statistical Analysis System

A state of the art of the overall energy efficiency of wood buildings : an overview and future possibilities

The main goal of this study was to review current studies on the state of the art of wood constructions with a particular focus on energy efficiency, which could serve as a valuable source of information for both industry and scholars. This review begins with an overview of the role of materials in wood buildings to improve energy performance, covering structural and insulation materials that have already been successfully used in the market for general applications over the years. Subsequently, studies of different wood building systems (i.e., wood-frame, post-and-beam, mass timber and hybrid constructions) and energy efficiency are discussed. This is followed by a brief introduction to strategies to increase the energy efficiency of constructions. Finally, remarks and future research opportunities for wood buildings are highlighted. Some general recommendations for developing more energy-efficient wood buildings are identified in the literature and discussed. There is a lack of emerging construction concepts for wood-frame and post-and-beam buildings and a lack of design codes and specifications for mass timber and hybrid buildings. From the perspective of the potential environmental benefits of these systems as a whole, and their effects on energy efficiency and embodied energy in constructions, there are barriers that need to be considered in the future

Drug-induced parkinsonism: diagnosis and management

Drug-induced parkinsonism (DIP) has been known for >60 years. It is the second leading cause of parkinsonism, but still underdiagnosis is likely to influence reported incidence figures. Since DIP is clinically undistinguishable from Lewy-body Parkinson’s disease, any new case of parkinsonism should prompt the search for an offending antipsychotic, hidden neuroleptic, or nonneuroleptic agent that may produce DIP. DIP is reversible upon drug withdrawal in most cases. There is no consensus regarding the duration of the recovery period to allow motor signs to fully remit in order to confirm the diagnosis of DIP following removal of the causative agent, but a drug-free interval of at least 6 months is generally recommended. Interestingly, up to 30% of DIP cases may show persisting or worsening motor signs beyond 6 months following drug withdrawal or adjustment, due to complex postsynaptic and presynaptic factors that may variably interact to negatively influence nigrostriatal dopamine transmission in a so-called “double-hit” hypothesis. The condition significantly impacts on quality of life and increases the risks of morbidity and mortality. Management is challenging in psychiatric patients and requires a team approach to achieve the best outcome

Investigation of the sulphate-induced freezing inhibition effect from CloudSat and CALIPSO measurements

The hypothesis according to which higher sulphate concentrations favor ice clouds made of larger ice crystals is tested using data sets from the CloudSat and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellites. This is a potential consequence of the sulphate-induced freezing inhibition (SIFI) effect, namely, the hypothesis that sulphates contribute to inhibit the onset of ice crystal formation by deactivating ice-forming nuclei during Arctic winter. A simple index based on the backscattering at 532 nm and the color ratio from the CALIPSO lidar measurements is compared against in situ sulphate concentration time series and used as a proxy for this variable. An algorithm using the lidar data and the CloudSat radar microphysical retrievals is also developed for identifying cloud types, focusing on those supposedly favored by the SIFI effect. The analysis includes the effect of the lidar off-nadir angle on the sulphate index and the cloud classification, the validation of the index, as well as the production of circum-Arctic maps of the sulphate index and of the SIFI-favored clouds fraction. The increase of the lidar off-nadir angle is shown to cause an increase in the measured depolarization ratio and hence in the ability to detect ice crystals. The index correlates positively with both sulphates and sea salt concentrations, with a Pearson correlation coefficient (equation image) varying from 0.10 to 0.42 for the different comparisons performed. Ultimate findings are the results of two correlation tests of the SIFI effect, which allow for a new outlook on its possible role in the Arctic troposphere during winter