Perception of artisans towards bamboo preservation for improved product durability in Uganda

Bamboo continues to attract attention globally as a sustainable material and is used in many applications. However, the quality of bamboo products in Uganda remains poor and cannot compete in the local and international markets. Bamboo's low product quality is associated with poor raw material processing and limited preservation methods, which lead to the short service life of the products due to its susceptibility to bio-deterioration and degradation. To cope with the above, artisans in Uganda apply various preservation methods depending on their knowledge and available resources. In this paper, the authors seek to determine the methods used by the artisans to preserve bamboo, understand the background of their intention to preserve, and their perception towards bamboo preservation. The Theory of Planned Behaviour was used as the main framework to understand artisans' perceptions towards the intention to preserve bamboo. A cross-sectional survey with 186 randomly selected artisans working with bamboo was conducted across three agroecological zones presumed to be Uganda's main bamboo growing areas. The study reported 13 available bamboo species, with the artisans exploiting mainly three of these species. Most artisans (86%) were aware of the need to preserve bamboo, with 67.4% practising bamboo preservation. The artisans use different methods and chemicals for preservation, i.e. leaching (17%), smoking (14%), soaking in crude lake salt (31%), boric acid and borax solutions (20%), surface application (16%), and pressure treatment (1%). Ordinal logistic regression was used to model artisans’ intention to engage in bamboo preservation. Attitude and subjective norms were the psychological factors that significantly influenced artisans’ intention to preserve bamboo. Interventions that increase benefits accrued from preserved bamboo can improve artisans’ attitude and subjective norms and enhance their intention to engage in bamboo preservation

Advanced Technologies for Increasing the Durability of Timber and Extending Its Service Life

Wood is one of most used and appreciated material among humans, and is an irreplaceable choice for building furniture, utility poles, bridges, and more [...

Engineered Wood Material with Bio-Based Phase Change Material and Micronised Copper for Building Applications

In this study, pine sapwood was first impregnated with micronized copper (Cu) solution at concentrations of 5 and 10%, the samples then dried and impregnated with ethyl palmitate as a bio-based phase change material (BPCM). The leakage test showed slightly less leakage in this scenario compare to controls without copper. The mould test showed using copper solution, significattly improves the resistance of the composites to mould growth. Thermal tests showed using BPCM improves thermal conductivity and thermal mass of the composites, enabling them to store and release energy within the temperature range of 20-25ºC. It is observed that the copper did not improve thermal conductivity, and 5% copper showed the best performance in thermal mass improvement

Solid wood impregnated with a bio-based phase change material for low temperature energy storage in building application

Wood impregnated with a multicomponent mixture of fatty acids as a bio-based phase change material (BPCM) to improve its thermal characteristics was studied. The studied wood/BPCM composites can be used as internal elements in buildings for energy storage. Scots pine and beech sapwood were impregnated with a multicomponent mixture of linoleic acid and coconut oil fatty acids at a ratio of 20:80. Leakage test was conducted and revealed that the maximum leakage for pine and beech were 9 and 8%, respectively. Light microscopy was employed to demonstrate the distribution of the BPCM in the wood structure. Rays in both pine and beech wood served as pathways for impregnation of the BPCM to partly fill the tracheid lumens (pine) and vessels (beech). Thermal characterization of the studied samples employed T-history and DSC methods, concluding that the impregnated wood had significant thermal mass, ability to store excessive energy in terms of latent heat and keep the temperature constant for long time. The specific heat capacity of the impregnated samples was 4-5 J g(-1) K-1 i.e., higher than that of the untreated control samples of ca. 2 J g(-1) K-1. The thermal conductivity of the samples before and after the impregnation was measured using heat flow meter method and the results showed that the untreated beech wood had higher thermal conductivity compared to pine and the parameter improved when the cell lumens were filled with the BPCM. Scots pine wood with to 80% mass percentage gain (MPG) after impregnation demonstrated an increment in thermal conductivity of 33% while Scots pine and beech with 43 and 38% MPG demonstrated an increase of the conductivity with 8 and 11%, respectively

New hybrid bio-composite based on epoxidized linseed oil and wood particles hosting ethyl palmitate for energy storage in buildings

In this study, the incorporation of ethyl palmitate (EP) as a bio-based phase change material (BPCM) in wood particles, the preparation and properties of the novel biocomposite for building applications were investigated. The wood particle-based composites hosting BPCM were produced by cold compression moulding. The EP impregnation step was optimized in terms of uptake and its ratio by post-addition of non-impregnated fibers. The optimized wood particles/EP ratio were combined with 37.5% epoxidized linseed oil (ELO) as a binder to produce a composite with energy storage function containing more than 99% bio-ingredients. The optimum BPCM content in the composite was 25%. The produced biocomposites were characterized by T-hystory, DSC, TGA, and a moisture buffer test. The results revealed excellent moisture buffer values (2.07 g/m2 RH%) according to the Nordtest protocol, significant thermal mass, ability to store excessive energy in terms of latent heat and maintain the temperature constant for longer time, good thermal stability and improved specific heat capacity when compared to a reference composite without BPCM. The effect of incorporating BPCM into biocomposite for regulating temperature fluctuations was confirmed by comparing test prototype cubes, with and without BPCM, subjected to temperature fluctuation between 0 and 40 ◦C

Bio-based phase change material for enhanced building energy efficiency: A study of beech and thermally modified beech wood for wall structures

This study investigated the impregnation of beech and thermally modified beech (TMB) with a ternary mixture of capric acid, palmitic acid, and stearic acid as a bio-based phase change material (BPCM). Finite element method (FEM) was used to complement the experimental analysis by providing new insights into computational methods for simulating the behavior of BPCMs in untreated and TMB. The analyzed specimens namely beech and TMB were impregnated with BPCM; the TMB achieved 54% weight percentage gain (WPG) while untreated beech got 37%. Accordingly, a greater increase in the latent heat was obtained for TMB up to 90 J/g, while for untreated beech with BPCM up to 75 J/g. Impregnated specimens absorbed less moisture at relative humidity of air above 50%, likely caused by the high uptake and hydrophobic nature of the BPCM. The study highlights the research gap in performing mathematical simulations on wood samples with BPCM using material thermal properties derived from differential scanning calorimetry or T-History analysis. It shows that the direct use of these values for simulations leads to unacceptable outputs that result in high errors. The root mean square error for untreated and TMB samples impregnated with BPCM was in the range from 1.06 to 3.1 while that for untreated samples was in the range from 0.57 to 0.87, indicating that the main challenge in simulating and characterizing the samples is due to the interaction of the phase change material with the wood structure

Thermal performance and mold discoloration of thermally modified wood containing bio-based phase change material for heat storage

The work presents the results of thermal performance and mold discoloration of thermally modified wood-based composites incorporating multicomponent fatty acids as a bio-based phase change materials (BPCM). Thermally modified Scots pine (TMP), beech (TMB), and spruce (TMS) sapwood were impregnated with a multicomponent mixture of linoleic acid and coconut oil fatty acids at a ratio of 20:80. Samples with different BPCM uptakes were analyzed in the temperature range typical for building indoor conditions. Leakage tests were conducted and revealed that the maximum leakage for all the samples is 3% to 5%. T-history and heat flowmeter methods were used to evaluate the thermal characteristic of the composites. The incorporation of BPCM into thermally modified woods (TMWs) resulted in significant thermal mass improvements, expressed by the ability of the composites to store excessive energy in terms of latent heat and keep the temperature constant for long time. The specific heat capacity of the TMWs was around 2 J/g K, which increased to 4 to 8 J/g K after impregnation with BPCM, depending on the impregnation uptake. Results showed also that TMB has higher thermal conductivity than TMP and TMS, while incorporating of BPCM into these materials resulted in even improved thermal conductivity. Results showed that the thermal conductivity of TMP increased after incorporation of BPCM from 0.06 W/m K to 0.1 and 0.14 W/m K for TMP/BPCM with 48% and 95% uptake respectively. Mold tests showed that BPCM encapsulated in TMWs is less susceptible to mold discoloration compared to untreated wood

The contribution of G‑layer glucose in Salix clones for biofuels: comparative enzymatic and HPLC analysis of stem cross sections

Background Interest on the use of short rotation willow as a lignocellulose resource for liquid transport fuels has increased greatly over the last 10 years. Investigations have shown the advantages and potential of using Salix spp. for such fuels but have also emphasized the wide variations existing in the compositional structure between different species and genotypes in addition to their effects on overall yield. The present work studied the importance of tension wood (TW) as a readily available source of glucose in 2-year-old stems of four Salix clones (Tora, Björn, Jorr, Loden). Studies involved application of a novel approach whereby TW-glucose and residual sugars and lignin were quantified using stem cross sections with results correlated with HPLC analyses of milled wood. Compositional analyses were made for four points along stems and glucose derived from enzyme saccharification of TW gelatinous (G) layers (G-glucose), structural cell wall glucose (CW-glucose) remaining after saccharification and total glucose (T-glucose) determined both theoretically and from HPLC analyses. Comparisons were also made between presence of other characteristic sugars as well as acid-soluble and -insoluble lignin. Results Preliminary studies showed good agreement between using stem serial sections and milled powder from Salix stems for determining total sugar and lignin. Therefore, sections were used throughout the work. HPLC determination of T-glucose in Salix clones varied between 47.1 and 52.8%, showing a trend for higher T-glucose with increasing height (Björn, Tora and Jorr). Using histochemical/microscopy and image analysis, Tora (24.2%) and Björn (28.2%) showed greater volumes of % TW than Jorr (15.5%) and Loden (14.0%). Total G-glucose with enzyme saccharification of TW G-layers varied between 3.7 and 14.7% increasing as the total TW volume increased. CW-glucose measured after enzyme saccharification showed mean values of 41.9–49.1%. Total lignin between and within clones showed small differences with mean variations of 22.4–22.8% before and 22.4–24.3% after enzyme saccharification. Calculated theoretical and quantified values for CW-glucose at different heights for clones were similar with strong correlation: T-glucose = G-glucose + CW-glucose. Pearson’s correlation displayed a strong and positive correlation between T-glucose and G-glucose, % TW and stem height, and between G-glucose with % TW and stem height. Conclusions The use of stem cross sections to estimate TW together with enzyme saccharification represents a viable approach for determining freely available G-glucose from TW allowing comparisons between Salix clones. Using stem sections provides for discrete morphological/compositional tissue comparisons between clones with results consistent with traditional wet chemical analysis approaches where entire stems are milled and analyzed. The four clones showed variable TW and presence of total % G-glucose in the order Björn > Tora > Jorr > Loden. Calculated in terms of 1 m3, Salix stems Tora and Björn would contain ca. 0.24 and 0.28 m3 of tension wood representing a significant amount of freely available glucose

Enzymatic hydrolysis of the gelatinous layer in tension wood of Salix varieties as ameasure of accessible cellulose for biofuels

Background Salix (willow) species represent an important source of bioenergy and offer great potential for producing biofuels. Salix spp. like many hardwoods, produce tension wood (TW) characterized by special fibres (G-fibres) that produce a cellulose-rich lignin-free gelatinous (G) layer on the inner fibre cell wall. Presence of increased amounts of TW and G-fibres represents an increased source of cellulose. In the present study, the presence of TW in whole stems of different Salix varieties was characterized (i.e., physical measurements, histochemistry, image analysis, and microscopy) as a possible marker for the availability of freely available cellulose and potential for releasing D-glucose. Stem cross sections from different Salix varieties (Tora, Björn) were characterized for TW, and subjected to cellulase hydrolysis with the free D-glucose produced determined using a glucose oxidase/peroxidase (GOPOD) assay. Effect of cellulase on the cross sections and progressive hydrolysis of the G-layer was followed using light microscopy after staining and scanning electron microscopy (SEM). Results Tension wood fibres with G-layers were developed multilaterally in all stems studied. Salix TW from varieties Tora and Björn showed fibre G-layers were non-lignified with variable thickness. Results showed: (i) Differences in total % TW at different stem heights; (ii) that using a 3-day incubation period at 50 °C, the G-layers could be hydrolyzed with no apparent ultrastructural effects on lignified secondary cell wall layers and middle lamellae of other cell elements; and (iii) that by correlating the amount of D-glucose produced from cross sections at different stem heights together with total % TW and density, an estimate of the total free D-glucose in stems can be derived and compared between varieties. These values were used together with a literature value (45%) for estimating the contribution played by G-layer cellulose to the total cellulose content. Conclusions The stem section-enzyme method developed provides a viable approach to compare different Salix varieties ability to produce TW and thus freely available D-glucose for fermentation and biofuel production. The use of Salix stem cross sections rather than comminuted biomass allows direct correlation between tissue- and cell types with D-glucose release. Results allowed correlation between % TW in cross sections and entire Salix stems with D-glucose production from digested G-layers. Results further emphasize the importance of TW and G-fibre cellulose as an important marker for enhanced D-glucose release in Salix varieties

Novel hydrophobization of wood by epoxidized linseed oil. Part 1. Process description and anti-swelling efficiency of the treated wood

The known method of wood modification by epoxidized linseed oil (ELO) has a limiting practical application due to the rapid polymerization of ELO in the presence of acetic acid (AA) needed as a catalyst. The present study was designed to develop an alternative method by means of a two-step process to avoid the rapid polymerization. The treatment options were tested on Scots pine sapwood, with the dimensional stability (DS) of the treated samples in focus. The new method provided an anti-swelling efficiency (ASE) in the range of 40-57%, which was even better than the thermally modified (TM) reference samples with 40% ASE. The developed two-step process is a feasible and practical approach for ELO treatment of wood