This study investigates the effects of incorporating date palm wood powder (DPWP) on the thermal, physical, and mechanical properties of lightweight fired earth bricks made from clay and dune sand. DPWP was added in varying proportions (0 %, 5 %, 8 %, 10 %, 12 %, and 15 % by weight of the soil matrix) to evaluate its influence on brick performance, particularly in terms of thermal insulation. Experimental results revealed that adding DPWP significantly reduced the thermal conductivity of the bricks, achieving a maximum reduction of 56.41 %. However, the inclusion of DPWP negatively impacted the physical and mechanical properties of the samples. Among the tested bricks, those with 8 % and 10 % DPWP achieved a desirable balance, maintaining satisfactory mechanical strength within acceptable standards while achieving thermal conductivity values of 0.333 and 0.279 W/m & sdot;K, representing reductions of 37.29 % and 47.46 %, respectively. To further validate these findings, prototypes of the DPWP-enhanced fired bricks and commercial bricks were constructed and tested under real environmental conditions during both summer and winter seasons, over a continuous 12-h daily period. The DPWP-enhanced prototypes demonstrated superior thermal performance, with temperature differences reaching up to 3 degrees C compared to the commercial bricks. These findings highlight the potential of DPWP as a sustainable additive for improving the thermal insulation properties of fired earth bricks, thereby promoting eco-friendly and energy-efficient building materials for sustainable construction practices.
As lunar exploration advances, the development of durable and sustainable lunar surface architecture is increasingly critical, with a particular focus on material selection and manufacturing processes. However, current technologies and designs have yet to deliver an optimal solution. This study presented an innovative designs pattern for laser-sintered lunar soil bricks, namely a sintered glass outer layer and a core composed of lunar soil particles. For structural reinforcement purposes, a combined system of columns and slabs was implemented to improve the overall strength characteristics. This approach leverages the low thermal conductivity of lunar regolith particles in conjunction with the thermal stability, radiation resistance, and mechanical strength characteristics of glass. In this case, our simulations of heat conduction demonstrated a marked improvement in the thermal insulation properties of the new lunar soil bricks. The low thermal conductivity of lunar regolith effectively serves as an insulating layer, while the column, plate and glass outer layer, with their higher thermal conductivity, enable rapid thermal response across the entire structure and enhance spatial heat transfer uniformity. We further investigated the influence of structural variations on heat transfer mechanisms, revealing that the thickness of the glass layer exclusively modulates the heat transfer rate without altering its spatial distribution. Additionally, comparative analysis of all designed samples demonstrated that the novel sample displays superior thermal insulation properties, reduces average energy consumption by three quarters, and maintains adequate mechanical strength, alongside the proposal of a suitable assembly and construction methodology. Consequently, we believe that glassy composites exhibit substantial potential for space construction. These findings offer valuable insights and recommendations for material design in lunar surface construction.
The generation of polyethylene mulch film (PEMF) has promoted the rapid development of agriculture, while the non-degradability of it has caused the serious damage for the ecological environment. Currently, the biodegradable mulch film is considered as the most promising green substitutes for petroleum-based PEMF, owing to its environmental friendliness and biodegradability. Hence, this study fabricated a biodegradable mulch film (PSGA) through the crosslink (the esterification/amidation reactions and hydrogen bonds) between polylactic acid waste liquid (PLAWL) and sodium alginate (SA)/gum arabic (GA). Then attapulgite (ATP) was added to improve the mechanical properties. Therein, PLAWL was a kind of waste liquid from the fabrication process of polylactic acid (PLA) based on straw. At the same time, PSGA had similar insulation and water retention performance to PEMF and great UV resistance, thermal stability, and hydrophilicity surface. Additionally, pot experiment showed that PSGA could significantly promote the growth of Chinese white cabbage and the degradability ratio of that could reach 50% in a month. The total amounts of Rhizobiaceae (Ensifer and Allorhizobium-Neorhizobium-Pararhizobium, fixing free nitrogen gas and providing nitrogen nutrients for plants) in soil with PSGA was 12%, which was obviously higher than that in blank (4.5%). Therefore, this study provides a high-value recycling route for industrial waste liquid, offering an alternative solution to PEMF.
The production of agricultural residues causes environmental pollution, especially in regions with intensive horticultural production. The solution is to maximise the use of residues, applying the 'zero waste' model and using them to develop construction materials. Natural fibres used to reinforce materials have environmental and economic benefits due to their low cost. This research presents an innovative characterisation using an inverted-plate optical microscope, a high-resolution scanning electron microscope (HRSEM) and a 3D X-ray microscope. A physico-mechanical and chemical characterisation of horticultural fibres was also conducted. The fibres analysed were those produced in the highest quantities, including those from tomatoes, peppers, zucchinis, cucumbers and aubergines. The viability of these natural fibres for use as reinforcements in biocomposites was investigated. The analysis centred on studying the microstructure, porosity, chemical composition, tensile strength, water absorption and environmental degradation of the natural fibres. The results showed a porosity ranging from 47.44% to 61.18%, which contributes to the lightness of the materials. Cucumber stems have a higher tensile strength than the other stems, with an average value of 19.83 MPa. The SEM analysis showed a similar chemical composition of the scanned fibres. Finally, the life cycle of the materials made from horticultural residue was analysed, and negative GWP (global warming potential) CO2eq values were obtained for two of the proposed materials, such as stabilised soil reinforced with agricultural fibres and insulation panels made of agricultural fibres.
Grapevines in cold regions are prone to frost damage in winter. Due to its adverse effects on soil structure, plant damage, high operational costs, and limited mechanization feasibility, buried soil overwintering has been gradually replaced by no-burial overwintering techniques, which are now the primary focus for mitigating frost damage in wine grapes. While current research focuses on the selection of thermal insulation materials, less attention has been paid to the insulation mechanism of covering materials and covering methods. In this study, we investigated the insulation performance of two covering materials (tarpaulin and insulation blanket) combined with six height treatments (5-30 cm) to analyze the effect of insulation space volume on no-buried-soil overwintering. The results show that the thermal insulation performance of the insulation blanket is significantly better than that of the tarpaulin. The 5 cm height treatment under the tarpaulin cover and the 25 cm height treatment under the insulation blanket cover exhibited the best thermal insulation performance. Using a neural network machine learning approach, we constructed a model related to the height of the insulation material and facilitate the model's accurate predictions, in which tarpaulin R2branches = 0.92, R220 cm = 0.99, and R240 cm = 0.99 and insulation blanket R2branches = 0.89, R220 cm = 0.98, and R240 cm = 0.99. The model predicted optimal insulation heights of 6 cm for the tarpaulin and 22 cm for the insulation blanket. Factors like solar radiation within the insulation space, ground radiation, airflow, and material thermal conductivity affect the optimal insulation height for different materials. This study used a neural network model to predict the optimal insulation heights for different materials, providing systematic theoretical guidance for the overwintering cultivation of wine grapes and aiding the safe development of the wine grape industry in cold regions.
This study assesses the hygrothermal performance of the Photovoltaic External Thermal Insulation Composite System (PV ETICS), using a thick layer of mortar with Phase Change Material (PCM) granules as a passive heat sink. The experimental scenario involved the wall system exposure to real outdoor climate conditions during a 20-month long measurement period. Measured data were compared with results from the hygrothermal modelling. The findings reveal that with carefully designed diffusion channels the PV ETICS demonstrated no accumulation of moisture behind the vapour-tight PV panel. Long term hygrothermal modelling for PCM mortar moisture content with a previously calibrated model predicted stable moisture content around 0.03 m(3)/m(3), significantly lower than the moisture content during first 2 years. Relative humidity behind the PV panel falls into the hygroscopic range on the second spring after the construction. The annual maximum temperatures for PCM mortar during two summers were 69 degrees C, occurring in mid-August. Risk analysis was conducted with historic climate data to understand, whether higher PCM temperatures could be reached in the same climate for different years. Overall, the wall system showed no signs of extensive moisture damage during the testing period, but slight discolouring of the PCM mortar was recorded. This study contributes valuable insights into the practical viability of PV ETICS with PCM mortar, reaffirming its potential for application on larger scale on real building facades.
The growing demand for environmentally sustainable and biodegradable materials has intensified interest in alternative solutions for thermal insulation. This study explores the development of composite materials using mango seed shell biochar (MSSB) and soy protein isolate (SPI) as a biodegradable matrix-filler system. Mango seed shells, an abundant agro-industrial waste, were subjected to pyrolysis at 500 degrees C for 2 hours to produce biochar. The resulting MSSB was incorporated into SPI with glycerol as a plasticizer to fabricate composite sheets containing 10%, 20%, and 30% biochar by weight Thermal conductivity tests showed that increasing MSSB content led to a notable reduction in thermal conductivity, with the 30% MSSB composite achieving a value of 0.035 W/mK-comparable to commercial synthetic foams such as expanded polystyrene. Mechanical analysis revealed a tradeoff between tensile and compressive properties. While tensile strength decreased from 1.8 MPa for pure SPI to 0.7 MPa at 30% MSSB, compressive strength improved with increasing biochar content, peaking at 1.5 MPa.Biodegradability was evaluated through an 8-week soil burial test, which demonstrated accelerated degradation in composites with higher MSSB content, reaching up to 55% weight loss at 30% loading. These findings highlight the potential of MSSB-SPI composites as eco-friendly insulation materials suitable for green building and packaging applications. Future work will focus on mechanical property enhancement to expand the material's structural utility.
There is an increasing demand for sustainable construction materials to address the challenges posed by the environmental impact of the built environment (BE), which is driven by climate change, population growth, and urbanization. Conventional construction materials like cement contribute significantly to carbon emissions during production, transport, use, and disposal phases, and their poor thermal conductivity hinders efforts to maintain comfortable indoor environments. To address these challenges, there is an urgent need for innovative, locally sourced thermal insulation materials specifically designed for regions with extreme climates and high energy demands to maintain building comfort. This research explores synthesizing novel, environmentally friendly building materials using locally sourced date palm fiber waste and clay. The study also investigates the developed material's 3D printing (3DP) capabilities and optimizes its printing parameters with lab-scale prototypes. Additionally, thermo-mechanical characterization is conducted to assess its suitability for built environment applications. Different concentrations, from 1 to 5 wt% of date palm fiber to clay ratio (Dpf/C), were studied regarding microstructural, thermal, and mechanical properties, dimensional accuracy, and feasibility for 3DP of BE structures. Results demonstrated a significant reduction in thermal conductivity by 73%, achieving 0.244 W/mK, and an increase in compressive strength by 106%, reaching 10.9 MPa at 5 wt% Dpf/C. The promising thermomechanical properties of these composites and their suitability for 3DP support their use in real-world applications in the future's sustainable built environment. This scalable methodology can be adapted to regions with similar sustainable local and waste resources, advancing the circular economy.
Modern structures incorporating lightweight, low-stiffness floors face challenges for lowfrequency impact noise transmission. Using spring isolators or resilient layers (e.g., floating floors) to improve isolation in light weight floor can introduce variability over time and increase structural complexity, making the system more sensitive to construction errors. An alternative approach is reviewed in this work, using internal floor cavities that contain Granular Materials (GM). Previous studies describe GM particle dampers in different applications where large movements between particles result in significant energy losses. However, a review of the experimental methods used in those studies is needed to be able to quantify the energy losses in relation to the type and degree of impact excitation. Modelling approaches are reviewed comparing their computational demand and which properties of GM are included, motion regimes and container properties. These studies span both destructive and non-destructive testing methods and give some pointers to both the geometrical and mechanical properties of granules which influence dissipation. This review goes beyond structural damping to include airborne sound absorption provided by a granular bed. This additional attenuation can be significant over a wide frequency range. A small number of practical studies of GM integrated with light weight floors show improvement in impact sound insulation. However, the lack of more detailed knowledge of GM damping mechanisms and a better understanding of GM bed interactions with containers prevents optimization of their use for insulating floors against sound transmission. This review proposes a general framework for future GM research to guide the selection of appropriate GM and addresses what is needed for optimizing lightweight floor impact sound insulation.
Biodegradable thermal insulation foams are drawing widespread attention due to the growing environmental pollution and thermal energy waste. Polymer-based foams characterized by flexibility, recyclability, and excellent thermal insulation, hold immense promise for application domains aimed at decreasing thermal energy waste. Poly(butylene adipate-co-terephthalate) (PBAT) has been widely employed in terms of its superior mechanical properties and acknowledged biodegradability. However, owing to the poor foamability and inherent shrinkage of PBAT, it is still challenging to prepare high-performance PBAT foams with excellent thermal insulation. Herein, the biodegradable polycaprolactone (PCL) crystalline particles were introduced into the PBAT matrix. High mechanical strength and recyclable multifunctional PBAT foams were prepared by the physical foaming process. The presence of PCL can improve the crystallization and promote the formation of open-cell structures. Thanks to the heterogeneous nucleation and special open-cell structure, the achieved PBAT/PCL foam shows ultralow density (0.04 g/cm(3)), restricted shrinkage ratio (<5%), enhanced thermal insulation capacity (32.5 mW/mK), and good hydrophobicity (106.0 degrees). More importantly, compared with other degradable polymer foams, PBAT/PCL foam shows superior degradation ability in soil. Our method offers a novel alternative for producing environmentally friendly, recyclable, multifunctional thermal insulation foams, without the worries regarding biodegradability that are linked with nondegradable materials.