Institut Technologique Forêt Cellulose Bois-Construction Ameublement

Kiln operators are forced to rely on their own experience and expertise when adapting standard drying schedules to tackle changing situations or to better suit their needs. The online tuning of a mechanistic model and its use as forward control is therefore proposed to address the current lack of tools. An inverse analysis of the drying kinetics of wooden boards dried in an industrial kiln is carried out to determine the moisture transfer properties of the boards. The values obtained by the inverse method are found to be relatively close to those obtained by direct measurement. The mechanistic model is then used with these input values to simulate the drying of a stack of boards to find the best drying strategy to meet the objectives. This work focuses on achieving a compromise between quality and time. Several difficulties were encountered in developing this approach for a semi-industrial dryer, and some recommendations are made for developing this innovative strategy further.

Laboratory and field measurements of the impact sound acoustic performance of a CLT wood-based floors have been performed. French national regulation requires the use of the standardized tapping machine for impact sound performance measurements. Since the early 2000s, rubber ball impact source has been standardized in some Asian countries to measure and evaluate the low frequency impact sound performance of floors; this excitation source is now part of international standards concerning building acoustic measurement in laboratories and in-situ. Indeed, the impact sound level associated to this soft impact source is supposed to provide a better correlation with annoyance from jumping and/or running children in buildings. The paper reviews the measurements performed using the standard tapping machine and the rubber ball as impact source, on CLT based floors in a laboratory, as well as those on the CLT based experimental building. Impact sound improvements are presented and discussed. The necessity of measuring with both impact sources, rather than only with the tapping machine is examined.

Maritime pine (Pinus pinaster Ait.) is a major forest tree species in south-western Europe. In France, an advanced breeding program for this conifer species has been underway since the early 1960s. Openpollinated seed orchards currently supply more than 90% of maritime pine seedlings for plantation forestry. However, little is known about pollen contamination and mating structure in such seed orchards for maritime pine. We analyzed these features here, focusing on: i) the location of the seed orchard, ii) the year of pollination, and iii) the genotype of the tree from which seeds were collected. Parental analyses based on an optimized set of 60 SNP markers were performed on 2,552 seedlings with Cervus software (likelihood inference methodology). Pollen contamination rates were highly variable between seed lots (from 20 to 96%), with a mean value of 50%. Several interpretative factors were highlighted, including the distance between the seed orchard and external pollen sources, rain during the pollination period, seed orchard age, soil characteristics and seed parent identity. All parental genotypes contributed to the offspring as pollen parents, but differences in paternal reproductive success were detected. These differences were only partly explained by differences in the number of ramets of each parental genotype deployed in each seed orchard. Finally, the overall self-fertilization rate was estimated at 5.4%, with considerable variability between genotypes. These findings are useful to formulate recommendations for seed orchard management and for identifying new research perspectives. .

Hemicellulose is mechanocatalytically depolymerized to low molecular weight oligosaccharides with a DP lower than 9 in 70% yield, and without any solvent.

BackgroundDuring the kraft process to obtain cellulosic pulp from wood, most of the lignin is removed by high-temperature alkaline cooking, released in the black liquors and usually incinerated for energy. However, kraft lignins are a valuable source of phenolic compounds that can be valorized in new bio-based products. The aim of this work is to develop laccases capable of working under the extreme conditions of high temperature and pH, typical of the industrial conversion of wood into kraft pulp and fibreboard, in order to provide extremophilic biocatalysts for depolymerising kraft lignin, and enzyme-assisted technologies for kraft pulp and fibreboard production.ResultsThrough systematic enzyme engineering, combining enzyme-directed evolution and rational design, we changed the optimal pH of the laccase for oxidation of lignin phenols from acidic to basic, enhanced the catalytic activity at alkaline pH and increased the thermal tolerance of the enzyme by accumulating up to eight mutations in the protein sequence. The extremophilic laccase variants show maximum activity at 70 °C and oxidize kraft lignin at pH 10. Their integration into industrial-type processes saves energy and chemicals. As a pre-bleaching stage, the enzymes promote kraft pulp bleachability and significantly reduce the need for chlorine dioxide compared to the industrial sequence. Their application in wood chips during fibreboard production, facilitates the defibering stage, with less energy required.ConclusionsA set of new alkaliphilic and thermophilic fungal laccases has been developed to operate under the extreme conditions of high temperature and pH typical of industrial wood conversion processes. For the first time basidiomycete laccases of high-redox potential show activity on lignin-derived phenols and polymeric lignin at pH 10. Considering the extreme conditions of current industrial processes for kraft pulp and fibreboard production, the new tailor-made laccases constitute a step forward towards turning kraft pulp mills into biorefineries. Their use as biocatalysts in the wood conversion sector is expected to support the development of more environmentally sound and efficient processes, and more sustainable products.

The United States (U.S.). market for mass timber has advanced at an accelerated pace rarely seen for new products or product categories. A number of factors have made this possible, including an unprecedented amount of research and product testing, standard development and code changes, growth in manufacturing capacity, and education/support for individuals involved in mass timber projects. With a growing number of completed buildings in the U.S., there is now a signifi cant opportunity for technology transfer and outreach-i.e., to share best practices and lessons learned with the broader design community. As the U.S. wood industry's leading mass timber education organization, WoodWorks -Wood Products Council has developed a series of advanced design resources relevant to specifi c areas of mass timber design, engineering and construction. This approach, in contrast to developing an updated reference manual for mass timber design, allows fl exibility to respond to issues and technological advances, while making it easier for design teams to access needed information. WoodWorks is proposing that this approach be formalized with a compilation document that includes these and other assets aimed at supporting the design and construction of mass timber projects in the U.S.

Confidential deliverables from ECOBULK WP7: Life Cycle Thinking for the circular designed products.

Public deliverables from ECOBULK WP7: Life Cycle Thinking for the circular designed products.

Soil sampling depths strongly vary across soil studies. Stocks of elements (such as C, N) or organic matter in a soil layer can be simply calculated from stocks measured in its sublayers. This calculation is less obvious for other soil characteristics, such as soil organic carbon (SOC) persistence, complicating the comparison of results from different studies. Here, we tested whether Rock-Eval® parameters of a soil layer, characterizing soil organic matter and its biogeochemical stability, can be determined using Rock-Eval® data measured on its sublayers. Soil samples collected in 10 plots located in eight French forest sites, taken up at two different depths (0–30 cm, 30–50 cm), and their mixtures were analysed with Rock-Eval®. Expected values for the Rock-Eval® parameters of the soil mixtures were calculated either: (1) as the weighted mean of Rock-Eval® parameters measured on the two sublayers, or (2) based on a signal reconstructed as the weighted mean of Rock-Eval® thermograms recorded on the two sublayers. Our results showed a good agreement between measured and expected Rock-Eval® parameter values. However, when the clay content strongly differed between the two soil sublayers, the amount of pyrolyzed hydrocarbons measured on the soil mixtures was slightly lower than expected. We conclude that it is reasonable to calculate Rock-Eval® parameters of a soil layer, from the Rock-Eval® signature of its sublayers. Our findings facilitate the harmonization of Rock-Eval® data from large scale soil studies using different sampling depths.