Search Results (35)

Earth materials are recognized for their excellent thermal and hygrothermal properties but exhibit low mechanical resistance. Binder stabilization improves compressive strength but often increases the carbon footprint. This study evaluates the mechanical, thermal, hygrothermal, and environmental properties of 12 stabilized earth concrete formulations. The samples were prepared using four types of excavated earths (A, B, C, and D) with varying granular distributions and chemical compositions, stabilized with three industrial binders: two low-carbon activated GGBS-based binders (LN and LW) and a CEM II cement. The samples were cured at 20 °C and 100% relative humidity. Density, porosity, thermal conductivity, specific heat capacity, and Moisture Buffer Value (MBV) were measured at 28 days of curing, using standard methods from concrete and geotechnical fields, while compressive strength tests were performed at 7, 28, and 90 days. The results revealed that gravel-rich earths (A and B) demonstrated higher densities and compressive strengths compared to fine-rich earths (C and D). GGBS-stabilized earths exhibited superior mechanical performance (1.7–14.8 MPa) compared to cement-stabilized earths (0.8–3.8 MPa). Despite low binder content (7%), thermal and hygrothermal properties were largely influenced by the earth’s composition. Thermal conductivity (0.48–0.59 W·m⁻¹·K⁻¹), volumetric heat capacity (1661–2031 J·m⁻³·K⁻¹), and MBV (0.9–1.9 g·m⁻²·%RH⁻¹) were consistent with raw earth values, supporting thermal inertia and humidity regulation. The carbon footprint analysis showed that both LN and LW binders had the lowest emissions (29–34 kg CO₂·eq/m³), with LN binders demonstrating consistent normalized performance (5.2–6.2 kg CO₂·eq/m³·/MPa) and LW binders exhibiting superior mechanical performance and a lower normalized indicator (2.3–5.4 kg CO₂·eq/m³/MPa). Conversely, CEM II-stabilized formulations displayed the highest emissions (70–86 kg CO₂·eq/m³) and the least favorable compressive strength-to-carbon ratios. These findings emphasize the potential of stabilized earth concretes, particularly those with low-carbon GGBS binders, for sustainable and energy-efficient construction practices. Full article

Urbanization in hot and humid regions such as southern China has increased the demand for comfortable indoor environments. In order to design a material for efficient passive indoor humidity regulation, this study investigates a composite material that combines the hygroscopic properties of salt and the adsorption capacity of diatomaceous earth (DE). Firstly, we prepared DE and boehmite into moisture-absorbing porous materials. Then, the initial DE-based sample was innovatively doped with SiO₂ nanomaterials and loaded with LiCl to enhance the humidity regulation ability of the composite, especially in the adsorption and desorption ability of water vapour. The microstructure and phase composition of the composite samples were analysed, and we observed an increase in porosity, filling performance and capillary condensation upon the introduction of SiO₂ nanoparticles. The hygroscopic salt loaded into the pores can absorb more water when exposed to the ambient humidity. This synergic effect can effectively improve the hygroscopic performance of the composite material while maintaining the stability of the physical and chemical properties. The optimized samples showed a moisture absorption rate of 28% in high-humidity environments, meeting moisture buffer value evaluation standards. The study’s findings lay the foundation for the future integration of these materials through advanced manufacturing technologies. Full article

The viability of using Juncus acutus fibers as reinforcement material for developing lightweight sustainable non-structural construction materials in compliance with the valorization of local by-products has been investigated in this work. This study aims to investigate the effect of the chemical treatment of Juncus acutus fibers on the mechanical and hygric properties of bio-sourced clay–sand–Juncus acutus fiber composite. This lightweight specimen has been produced from a mixture of 60% natural clay and 40% sand by mass, as a matrix, and reinforced with different amounts of Juncus fibers. The fibers were used as a partial replacement of sand in the mixture by volume at 0% (control specimen), 5%, 10%, and 20%. In order to enhance interfacial bonding between the fibers and the binder matrix, which seriously limits the strength development of the composite, the fibers have undergone an NaOH alkali treatment with different concentrations of 1 and 2 wt. %. Morphological and elementary chemical component evaluations based on SEM micrographs and EDX analyses revealed that the 1 wt. % NaOH alkali treatment exhibited the most beneficial effect due to the removal of impurity deposits without significant surface damage to the fibers. This finding was highlighted through the tensile tests carried out which showed the tensile stress value of 81.97 MPa compared to those of the treated fibers with 2% NaOH (74.45 MPa) and the untreated fibers (70.24 MPa). However, mechanical test results, carried out according to the European Standard EN 196-1, highlighted the beneficial effect of the fiber alkali treatment on both the compressive and flexural strengths, particularly for the fiber contents of 5% and 10%, which corresponds to a strengthening rate of 25% and 30%, respectively. The examination of the hygroscopic properties of the samples, including capillary water absorption, water diffusivity, and moisture buffering capacity under the dynamic conditions have indicated that the specimen containing treated fibers exhibited a better moisture regulating property than that obtained with untreated fibers. However, the specimens with treated fibers are classified as excellent hygric regulators based on their moisture buffer values (MBV > 2 g/(m².%RH)), according to the NORDTEST classification. The results also indicated that the capillary water absorption and the apparent moisture diffusivity of composites were lowered due to high fiber-matrix interfacial bond after fiber treatment. Consequently, the composite with treated fibers is less diffusive compared to that with untreated fibers, and thus expected to be more durable in a humid environment. Full article

This article calculates horizontal and vertical heat and moisture fluxes in the wall based on measurements of temperature and relative humidity in the building wall. It was a basement wall that was close to the ground on one side and the basement ceiling on the other, which increased the difficulty in problem simulation. The brick material from the wall was also analyzed under an electron microscope and its elemental composition was determined using the EDX (Energy Dispersive X-ray spectroscopy) method. The brick had a relatively uniform elemental composition apart from several variations in calcium content. Monthly, daily, and hourly heat and moisture fluxes were determined. The tested wall was characterized by low humidity, and the values obtained of the moisture fluxes confirmed this. The maximum recorded relative humidity inside the wall is 57.89%, and the minimum is 43.99%. The effect of buffering moisture by brick material was noticed. Vertical streams of water vapor were found to be important in the moisture balance of the tested partition. The maximum heat flux through the tested wall area in August was 0.06 W, and the minimum in January was −0.2 W. The maximum moisture flux in August was 5 × 10⁻¹¹ kg/s, and the minimum in January was −5 × 10⁻¹¹ kg/s. Full article

This study investigated the use of non-formaldehyde binders in the production of plywood panels, focusing on mixtures containing 70% poly 4,4’-methylene diphenyl isocyanate (pMDI) and 30% soy flour (SF), along with blends of soy flour and agricultural residues (olive by-products—with and without extraction of their bioactive ingredients—and defatted hemp seeds). The basic properties of these biomaterials, such as moisture content, pH, and buffering capacity, were determined with laboratory analysis. Adhesive mixtures were characterized using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and thermogravimetric analysis (TGA). The adhesive’s bonding ability was evaluated by manufacturing plywood panels on a laboratory scale, simulating industrial practices. The glue lines were visually inspected with a stereomicroscope. Micro-ATR-FTIR study of the cross-sections of plywood panels showed the full consumption of isocyanate groups indicating effective curing of the adhesive. Mixtures containing olive residues, particularly olive skin and stones, showed improved thermal stability in the TGA study. The mechanical properties of the plywood panels were assessed with three-point bending tests, while their shear strength and wood failure performance were tested according to the European standards used in the relevant industry (EN 314.1:2004 and EN 314.2:1993). In terms of flexural properties, the adhesive with non-extracted (NE) residual olive skin (ROS) showed the highest flexural strength of around 17 MPa and a flexural modulus of 650 MPa. The formulations containing extracted materials from hemp seeds (HSs) and residual olive skin (ROS) showed the best overall performance with wood failure values of 85% and 75% after the most severe cyclic test (EN314.1:2004-Pretreatment 5.1.3). Overall, the results showed that binders prepared with residual olive skin and defatted hemp seeds have promising performance and can be used in the manufacture of plywood panels. Full article

The internal structures and the hygroscopicity of bio-based boards consisting of giant reed (Arundo donax L.) and hazelnut shells as bio-aggregates, and a sodium silicate solution as the adhesive, were investigated. The aim was to evaluate the influence of each material (the bio-aggregates and adhesive) and their distributions in the boards on the final performance. By carrying out X-ray computed tomography, the internal structures and the porosities of the boards were determined, allowing important considerations of their hygroscopicity. The voids’ percentages were between 26% and 36% of the total volume of the composites. Both the materials and the composites demonstrated high hygroscopicity. In particular, the mixtures of the bio-aggregates and the sodium silicate allowed reaching a moisture buffering value of 7.44 g/(m²%RH) for the A. donax-based composite, 3.86 g/(m²%RH) for the hazelnut-shell-based composite, and 4.65 g/(m²%RH) for the mixture-based composite. Besides the identification of the contributions of the materials, a detailed discussion of the assessed properties was carried out to use these bio-based boards in vernacular historic construction. The results show how the aggregate type and the adhesive content affected the final behavior, demonstrating the importance of a conscious material choice. Furthermore, helpful information for the future development of these types of bio-based boards and their possible optimization was provided. Full article

In this article, the functional properties of hemp concrete are studied. Hemp concrete stands to reduce the carbon impact and improve the energy consumption of houses. Hence, numerous properties are measured: mass and dimension (volume) variations are found, as is the variability in hygrothermal properties (density, thermal conductivity, heat capacity, moisture buffer value, and water vapor permeability). This entry proposes three different characterization campaigns. The first is a short introduction to the spatial variability in thermal conductivity; the second is dedicated to the study of univariate variations in the mass, volume, and hygrothermal properties of hemp concrete samples. The last one tackles the aging evolution of the properties characterized during the second campaign, in which the samples follow several aging protocols, including exposure to outdoor conditions, the application of immersion-drying cycles, and the application of freeze–thaw cycles. A set of samples is kept under control conditions to allow for comparison. As the main result, spatial variability was found in the material. This is related to the random manufacturing variability or the spatial position regarding the height of the manufactured element. A high univariate variability is found across hemp concrete samples. Moreover, the storage of samples under stable reference conditions implies very little change in the studied materials’ properties, whereas all accelerated aging protocols implied major changes of properties. In particular, we observed an evolution of the thermal conductivity of the samples kept under control conditions for 4 months, with the thermal conductivity ranging from −2.7% to +6.3% with a mean evolution of +1.22%. We observed an increase in the same property, ranging from +2.7% to +18.3%, with a mean of +9.0% for samples kept for 4 months under natural outdoor conditions, an increase ranging from +7.3% to +23.6% with a mean of +15.2% for samples that had undergone 20 cycles of immersion-drying, and an evolution of this property ranging from −5.6% to +12.3% for samples that had undergone 20 freeze–thaw cycles. Full article

This case study focuses on twelve compacted clay soil samples to understand their fundamental physical and thermal properties. For each sample, the density, thermal conductivity, thermal diffusivity, specific heat, and drying shrinkage were assessed. The identification and characterisation of the materials were also carried out by positioning them into the ternary diagram based on the percentage of sand, silt, and clay. These properties are definitive for the performance characteristics of materials used in rammed earth wall construction. The aim is to provide information for better knowledge and prediction regarding the dynamic heat flow in rammed earth walls. Experimental results show a relatively wide range of values for each property, reflecting the diverse properties of the sampled clays. The thermophysical characteristics of the 12 types of earth analysed showed correlations with reports in the literature in terms of density (1490–2150 kg/m³), porosity (23.22–39.99%), specific heat capacity (701–999 J/kgK), and thermal conductivity (0.523–1.209 W/mK), which indicates them as materials suitable for use in the construction of rammed earth walls. Using test data, a dynamic assessment of heat flow through simulated rammed earth walls was performed. For a better understanding of the results obtained, they were compared with results obtained for simulations where the building element would be made of concrete, i.e., a mineral wool core composite. Thus, heat flux at the wall surface and mass flux, respectively, during the 16 years of operation showed similar evolution for all 12 types of clay material analysed, with small variations explained by differences in thermophysical characteristics specific to each type of S1–S12 earth. In the case of walls made from clay material, there is a stabilisation in the evolution of the water content phenomenon by the 5th year of simulation. This contrasts with walls made of concrete, where the characteristic water content appears to evolve continuously over the 16-year period. Therefore, it can be said that in the case of the construction elements of existing buildings, which have already gone through a sufficient period for the maturation of the materials in their construction elements, the rammed earth wall quickly develops a moisture buffer function. In the case of simulating a mineral wool core composite wall, it cannot perform as a temperature or humidity buffer, exhibiting an enthalpy exchange with indoor air that is only 4% of that of the rammed earth walls; consequently, it does not play a significant role in regulating indoor comfort conditions. Overall, there is confirmation of the temperature and moisture buffering capabilities of rammed earth walls during both warm and cold periods of the year, which is consistent with other reports in the literature. The findings of this research provide a better insight into clay as a material for rammed earth walls for more efficient design and construction, offering potential improvements regarding indoor comfort, energy efficiency, and sustainability. The data also provides useful information in the fields of architecture and civil engineering regarding the use of clay as an eco-friendly building material. The results emphasise the importance of thoroughly understanding the thermophysical properties of clay to ensure the efficiency of rammed earth construction. Full article

The exploration of the western forests of Algeria led to the remarkable discovery of the first occurrence of Lepista sordida, an edible wild mushroom of significant culinary importance for the local community, traditionally consumed in its natural state. This discovery was made possible through the use of various methods, including macroscopic observations (revealing a violet color) as well as microscopic observations conducted using scanning electron microscopy (SEM), revealing a cylindrical shape with distinct contours. Additionally, molecular analyses were conducted. Genomic DNA was extracted from the mycelium, followed by DNA amplification using specific primers targeting the internal transcribed spacer region (ITS1 and ITS2). After PCR reactions and sequencing of the obtained amplicons, the nucleotide sequences of the mycelium were submitted to the GenBank database of NCBI with the assigned accession number: MZ928450.1. These sequences were subsequently used to construct the phylogenetic tree. Furthermore, an in-depth study of physicochemical parameters was undertaken to determine the optimal conditions for cultivating the mycelium of this edible wild mushroom, including pH, temperature, relative humidity, and light. Different temperatures were examined: 20, 25, 30, 35, 40, and 45 °C. The effect of pH on mycelium growth was studied using a PDA agar medium with buffered values of 4, 5, 5.6, 6, 7, and 8. Similarly, six levels of relative humidity were tested: 14, 50, 74, 80, 95, and 100%. A study on the impact of light on mycelium growth was conducted by exposing Petri dishes inoculated with PDA to a light intensity of 500 lux for 5, 10, 15, 20, and 24 h. The results clearly demonstrated that variations in these different physicochemical parameters significantly influenced mycelium growth. For the Lepista sordida strain, growth was favored at pH levels of 4, 5, 6, and 6, with no growth observed at pH 7 and 8. The optimal temperature range for mycelium growth of Lepista sordida was 20–25 °C, while no growth was observed at 30, 35, 40, and 45 °C. Relative humidity levels of 74, 80, and 95% showed no significant differences. Optimization of mycelium growth and primordia production in Lepista sordida were successfully achieved. Optimal conditions for the primordia phase were identified as 25 °C, with humidity ranging from 90 to 95%. A nutritional analysis of fresh sporophores was conducted using established analytical methods. Notably, the nutritional composition of Lepista sordida sporophores exhibited high significance for the following parameters: moisture content (67.23 ± 1.90%), ash content (9.35 ± 0.66%), fat content (3.25 ± 0.24%), protein content (17.22 ± 0.38%), and carbohydrate content (63.83 ± 1.23%). Full article

The objectives of our survey were to determine the most important environmental factors within buffer zones that influenced mollusc communities and to evaluate the ecological conservation value of natural aquatic habitats (NAHs) that support mollusc species. Analysis of the spatial structure of buffer zones and catchments was based on a set of landscape metrics. Land cover classes were determined, and buffer zones within a radius of 500 m from a sampling point were marked out. Mollusc samples were collected from each NAHs. Our results showed that the number of patches and mean patch size were most associated with the distribution of mollusc species. Within patches of buffer zones, the length of the catchment boundaries with low-density housing, an increasing area of forest and pH of the water were also significant. Our results proved that landscape metrics provide essential information about catchment anthropogenic transformation. Therefore, landscape metrics and the designated buffer zones should be included in restoration plans for the river, water bodies and adjacent habitats as elements of modern, sustainable water management. NAHs located along a valley of a lowland river provide refuges for molluscs, play an essential role in the dispersal of IAS, create important protective biogeochemical barriers for rivers, constitute necessary sources of moisture and water and support microhabitats for distinct mollusc communities, especially in the context of global warming. Full article

Attention to the association of cellulolytic bacteria with probiotic potential as an additive in animal feeding has risen in the last decades. Such additive use in livestock feed is essential in improving animal health, growth, and production performances. This study was designed to identify probiotic characteristics and test the cellulolytic ability of Bacillus strains isolated from the dromedary gastrointestinal tract. Thus, thirty-two Bacillus strains were tested for their cellulolytic ability on cellulose Congo-red agar media. Among the isolates, only the strain D1B3 showed the largest degradation zone (2.4 cm) and was identified as Bacillus amyloliquefacians by 16S rRNA gene sequence analysis. Solid-state fermentation (SSF) retained this strain for cellulase and biomass production using wheat bran as a substrate. The fermentation was optimized through a central composite design, by exploring three factors: incubation temperature, moisture ratio, and pH. Biomass and cellulose enzyme activity were selected as responses and corresponding regression coefficients were calculated. The optimal parameters were: liquid-to-solid ratio (1.19%), pH buffer (6.2), and incubation temperature (36.99 °C) to obtain the highest level of biomass and cellulose enzyme activity reaching a value of 9.828 log CFU/g and 0.0144 g/L.min, respectively. The potentiality of Bacillus amyloliquefacians D1B3 as a probiotic was examined in vitro. It also showed antimicrobial activity against Pseudomonas aeruginosa 9027, Klebsiella pneumoniae, and Escherichia coli 10536. The isolate tolerates low pH and bile salt (0.3% Oxygall). The hydrophobicity and coaggregation abilities were 1.7% and 69.79%, respectively. The results indicated that Bacillus amyloliquefacians D1B3 could be a potential probiotic additive for improving in vitro fermentation of wheat bran and suggests the possibility of combining the probiotic attributes of this strain with its cellulolytic ability to enhance the rumen fermentation of animal feed. Full article

Porous materials are able to exchange moisture with the surrounding air. The more hygroscopic they are, the more they contribute to regulate ambient humidity. This ability is characterized by the moisture buffer value (MBV) which is measured under dynamic solicitations according to different protocols. The NORDTEST protocol is the most commonly-used. It gives recommendations regarding the air velocity and the ambient conditions for initial stabilization. The purpose of this article is to measure the MBV according to the NORDTEST protocol and to study the effect of air velocity and of initial conditioning on the MBV results for different materials. Two mineral and two bio-based materials are considered: gypsum (GY), cellular concrete (CC), thermo-hemp (TH) and fine-hemp (FH). Following the NORDTEST classification, GY is a moderate hygric regulator, CC is good, TH and FH are excellent. When the air velocity ranges from 0.1 to 2.6 m/s, the MBV of GY and CC materials remains constant, but the MBV of TH and FH materials is highly affected. The initial conditioning has no effect on the MBV, but has an effect on the water content of the material, whatever the material. Full article

Extreme climate anomalies are expected to become more frequent under climate change, and rare extreme events, such as the 2021 western North American heat wave, provide an opportunity for comparative empirical analysis of ecosystem resilience. This study evaluates anomalies in a remotely sensed enhanced vegetation index (EVI) in the aftermath of the record-setting western North American heat wave in 2021, with temperatures approaching 50 °C in coastal and interior regions of the Pacific Northwest. The results show that the forest ecosystems most affected were not necessarily those that experienced the highest absolute temperature values. Instead, the greatest reductions in greenness were observed across northern coastal temperate rainforests. Most affected were the cooler, very wet, hyper-maritime ecosystems that are normally buffered from large temperature fluctuation by a strong oceanic influence. In contrast, moisture-limited forests of the interior plateau of British Columbia, where most of the all-time record temperatures occurred, generally showed normal or even increased productivity during and after the heat wave. A putative explanation for this heat resistance of interior forests was normal or above average precipitation leading up to the heat event, allowing for transpirational cooling. Nevertheless, the data suggest that the largest protected coastal temperate rainforest in the world, with 6.4 million hectares, is comparatively more vulnerable to extreme heat waves, which are expected to become more frequent under climate warming, than other ecosystems of the Pacific Northwest. Full article

The effect of the ensiling length (3, 6, or 9 months), and the processing by dehydration (D) or dehydration and pelleting (P) with respect to the fresh silages (F) were studied in vitro on three maize cultivars in three incubation runs to study the effect of these factors on the nutritive value of maize silage. Gas production pattern, in vitro true digestibility (IVTD), methane concentration (6 and 12 h), ammonia, and volatile fatty acid concentration (VFA) at 12 h were measured. The moisture and pH of F averaged 676 g/kg and 4.09, respectively, and were not affected by the ensiling length, but moisture was reduced, and the pH increased in D and P with respect to F (p < 0.05). The ensiling length did not affect the chemical composition, but differences among the processing forms were detected in a higher acid detergent insoluble nitrogen (ADIN) proportion in P than D, and D than F (p < 0.001). Silages opened at 9 months showed the lowest gas production (p < 0.05), and those that opened after 3 months showed the highest IVTD. The effects of processing on nutrient utilisation only manifested on 3 month silages, with the volume of gas production and IVTD being lower in D than F. However, processing tended (p = 0.064) to reduce the methane proportion at 12 h, indicating both a more efficient fermentation and a lower potential of greenhouse gas emissions compared to the fresh silages. Extending the length of ensiling to 9 months reduced the fermentation of maize silage. The processing increased the dry matter and buffered the feed as well as contributed to an increase in fermentation in 3 month silages. Full article

Background: Tocopherol acetate (TA) is known as a skin moisturizing and photoprotective agent. One major drawback with tocopherol and its derivatives remains its limited stability. Aim: To develop highly stable TA-containing ethosomal gel (TAEG) as an advanced dosage form. Methods: A cold method technique was used to produce the ethosomes. An in vitro evaluation of viscosity, conductivity, and pH stability was carried out for three months. An in vitro physical characterization of the nanoparticles (NPs) that included particle size (PS), zeta potential (ZP), transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy analysis was then performed. Organoleptic evaluation, thermostability at 8 °C, 25 °C, 40 °C and 40 °C ± 75% RH, pH, conductivity, viscosity, and spreadability measurements were also performed in vitro for three months. An ex vivo permeation study was performed in phosphate-buffered solution (1× PBS; pH 5.5 or pH 7.4) at 37 ± 0.2 °C by using rat abdominal skin and the Franz diffusion cell method. The data of three independent experiments were expressed as mean ± SD. A two-way ANOVA was applied to compare data on TAEG versus TA control gel (TACG). Results: PS of the ethosomes was in the range of 144–289 nm. A total of nine formulations were developed. Optimized TAEG formulation (TA-5) was selected based on the highest entrapment efficiency (EE) of 99.71%, while the stability, the PS, and the uniformity-based polydispersity index (PDI) were also among the best. TA-5 exhibited smooth spherical ethosomal NPs with PS of 200.6 nm, ZP value of ?18.6 V, and PDI of 0.465. Stability data obtained for TA-5 in terms of rheology, conductivity, and pH presented no significant change (p > 0.05) during the entire study duration. Rheological studies indicated that TA-5 followed a non-Newtonian behavior of shear thinning system. The ex vivo drug permeation was 44.55 ± 0.01% in TA-5 and the drug retention in skin was 51.20%, which was significantly higher than TACG as observed after 24 h permeation study (p < 0.05). Conclusions: The newly developed TAEG formulation appears promising to enhance the effectivity of TA and its topical application. Full article