Low Moisture Research Articles

OPTIMIZATION OF PROCESS PARAMETERS FOR ENHANCING THE SKIN PERMEATION EFFICIENCY OF NISOLDIPINE LOADED ULTRA DEFORMABLE VESICLES IN TRANSDERMAL PATCHES

Objective: The study aimed to address the limitations of oral delivery and enhance the bioavailability of nisoldipine (NSD) through the development of transferosomal transdermal patches containing ultra-deformable transferosomes. Methods: NSD, known for its low oral bioavailability and adverse effects, was encapsulated in transferosomes using a thin film hydration method. 17 formulations were made using Box Behnken Design, varying Dipalmitoylphosphatidylcholine (DPPC), span-80, and stirring speed, and were evaluated for vesicle size, Polydispersity Index (PDI), and Entrapment Efficiency (EE%). The optimal formulation, selected based on these parameters, was combined into Transdermal Patches (TPs). The patches underwent extensive testing for physicochemical properties, in vitro and ex-vivo permeation, and skin irritancy. Results: The results showed transferosomes with Vesicle Sizes (VS) ranging from 124±2.25 to 400±1.55 nm and EE% from 52.88±0.23 to 90.01±1.58%, with Zeta Potentials (ZP) between-48 to-20 mV. The patch thickness (0.66±0.02 mm) and weight per square inch (382.1±1.69 mg) showed consistent manufacturing, while the Water Vapor Transmission Rate (WVT) (1.54±0.01g/m²/24h), low moisture content (1.07±0.01%), and regulated moisture absorption (3.78±0.01%) maintained formulation stability. In vitro and ex-vivo permeation indicated superior drug permeation for transferosomal patches (NP) compared to plain nisoldipine patches (NP-N), with permeation directly proportional to PEG-400 concentration. Additionally, the transferosomal patches were found to be free from skin irritation. Conclusion: The optimized Niosoldipine transferosomal patch (NP-3) composition displays good folding endurance (FE) 97.67±0.47, required for transdermal systems, and successfully allows drug permeation (DP) at 86.39±2.64% in a short timescale. Hence, the study concludes that transferosomal patches of NSD offer a promising approach for effective transdermal delivery, potentially improving hypertension management by providing a controlled and prolonged drug release.

An automated AI-powered IoT algorithm with data processing and noise elimination for plant monitoring and actuating

This article aims to develop a novel Artificial Intelligence-powered Internet of Things (AI-powered IoT) system that can automatically monitor the conditions of the plant (crop) and apply the necessary action without human interaction. The system can remotely send a report on the plant conditions to the farmers through IoT, enabling them for tracking the healthiness of plants. Chili plant has been selected to test the proposed AI-powered IoT monitoring and actuating system as it is so sensitive to the soil moisture, weather changes and can be attacked by several types of diseases. The structure of the proposed system is passed through five main stages, namely, AI-powered IoT system design, prototype fabrication, signal and image processing, noise elimination and proposed system testing. The prototype for monitoring is equipped with multiple sensors, namely, soil moisture, carbon dioxide (CO2) detector, temperature, and camera sensors, which are utilized to continuously monitor the conditions of the plant. Several signal and image processing operations have been applied on the acquired sensors data to prepare them for further post-processing stage. In the post processing step, a new AI based noise elimination algorithm has been introduced to eliminate the noise in the images and take the right actions which are performed using actuators such as pumps, fans to make the necessary actions. The experimental results show that the prototype is functioning well with the proposed AI-powered IoT algorithm, where the water pump, exhausted fan and pesticide pump are actuated when the sensors detect a low moisture level, high CO2 concentration level, and video processing-based pests’ detection, respectively. The results also show that the algorithm is capable to detect the pests on the leaves with 75% successful rate.

Nitrogen Storage in Rice: Analysis of Physical Quality by Respiration, Weight, and Storage According to Nitrogen Ratio

Various studies have been conducted to minimize the damage and loss of stored grain. For safe storage, the moisture content must be reduced, or respiration must be suppressed. In this study, grain respiration rates were analyzed under various nitrogen atmospheric conditions, and the quality of stored rice was evaluated. As the nitrogen content of the storage space increases, the respiration rate of the grain decreases accordingly. In this study, the effect of the modified atmospheric nitrogen concentration on reducing respiration was determined. When predicting weight loss due to respiration, low moisture content, and high nitrogen concentration could reduce loss. Quality analysis was performed to compare different respiration rate conditions and showed that lower oxygen concentration and moisture content were associated with safer storage. Our results indicate that changes in atmospheric conditions depending on climate and storage conditions can be considered for the safe storage of harvested rice.

Burn Period: A use-inspired metric to track wildfire risk across Arizona and New Mexico in the southwest U.S.

Abstract Numerous tools and indices exist for wildland fire managers to anticipate and track changes in wildfire risk driven by variability in weather and climate conditions at hourly to seasonal scales. However, in working closely with southwest U.S. managers, we learned of a simple meteorological metric being informally used, but not widely accessible in existing tools or information products, to gauge short-term changes in wildfire risk. This metric, termed ‘Burn Period’ (BP), is the local count of hours per day with relative humidity values equal to or less than 20%. Our collaboration led to the development of an experimental tool called the ‘Burn Period Tracker’ to ease access and promote use of BP values for planning and response. This study is a climatological analysis of BP values at 124 fire weather stations across Arizona and New Mexico for the period 2000-2022 to aid in interpretation and understanding of this use-inspired metric. BP values reflect the strong seasonality in temperature and moisture deficit-driven wildfire risk across the southwest U.S., with risk climbing through the arid spring season, peaking in June, and then falling rapidly with the onset of the summer monsoon in July. Regression analyses show that short-term variability in BP values are driven by variability in low level atmospheric moisture in all months with strongest relationships during the summer after the onset of the monsoon. This study highlights the utility of BP as a short-term wildfire planning tool as well as an example of collaborative weather and climate services development.

Optimization of Ferimzone and Tricyclazole Analysis in Rice Straw Using QuEChERS Method and Its Application in UAV-Sprayed Residue Study

Rice straw is used as livestock feed and compost. Ferimzone and tricyclazole, common fungicides for rice blast control, can be found in high concentrations in rice straw after unmanned aerial vehicle (UAV) spraying, potentially affecting livestock and human health through pesticide residues. In this study, an optimized method for the analysis of the two fungicides in rice straw was developed using the improved QuEChERS method. After the optimization of water and solvent volume, extraction conditions including ethyl acetate (EtOAc), acetonitrile (MeCN), a mixed solvent, and MeCN containing 1% acetic acid were compared. Different salts, including unbuffered sodium chloride, citrate, and acetate buffer salts, were compared for partitioning. Among the preparation methods, the MeCN/EtOAc mixture with unbuffered salts showed the highest recovery rates (88.1–97.9%, RSD ≤ 5.1%). To address the severe matrix effect (%ME) of rice straw, which is characterized by low moisture content and cellulose-based complex matrices, samples were purified using 25 mg each of primary–secondary amine (PSA) and octadecylsilane (C18), without pesticide loss. The developed method was validated with a limit of quantification (LOQ) of 0.005 mg/kg for target pesticides, and recovery rates at levels of 0.01, 0.1, and 2 mg/kg met the permissible range (82.3–98.9%, RSD ≤ 8.3%). The %ME ranged from −17.6% to −0.3%, indicating a negligible effect. This optimized method was subsequently applied to residue studies following multi-rotor spraying. Fungicides from all fields and treatment groups during harvest season did not exceed the maximum residue limits (MRLs) for livestock feed. This confirms that UAV spraying can be safely managed without causing excessive residues.

Tobacco stalk nanofibrillated cellulose: An eco-friendly binder on fluidized bed granulation

The search for new excipients that provide formulation alternatives over existing ones and that are derived from natural resources has advanced over the years. Emerging from this scenario, an important alternative to traditional excipients is nanofibrillated cellulose (NFC), which is generally obtained from agricultural wastes and is a cellulose-rich material. Most of the time, the nanofibers are presented in aqueous dispersions that form a highly entangled network of fibrous particles that exhibit gel-like behavior. Therefore, the present work aimed to explore the gel-like behavior of NFC from tobacco stalks to evaluate it as a binder in a fluid bed granulation process for further application as a pharmaceutical ingredient. The granulation process was carried out using top spray mode with an inlet air temperature of 80 °C, airflow between 9 and 11 mm3 h−1, and atomizing air pressure of 0.7 bar. Povidone (PVP) was used as a standard binder for comparison purposes. The binder systems were sprayed on the powder blend of theophylline and maltodextrin at a feed rate of 3.05 mL⋅min−1. Granule properties, such as yield, moisture content, morphology, label-free Raman imaging, particle size distribution, drug content, and flow properties, were evaluated. The process using NFC provided granules with excellent drug uniformity, low moisture content (<2 %), high yield (>92 %), and passable flow properties. Their behavior was comparable to that of granules prepared with the classical PVP binder system. Therefore, this study opens a perspective for the reuse of NFC from tobacco stalk, an agricultural waste, as an alternative binder for the granulation process, contributing to environmental sustainability.

Subsurface Sediment Transport in the Shallow Vadose Zone of Fine‐Textured Soils With Heterogenous Preferential Flows

ABSTRACTSubsurface sediment transport in tile‐drained landscapes occurs through macropores; however, little is known regarding how heterogeneous preferential flows influence fluxes. We performed laboratory rainfall simulations on 10 intact core lysimeters from a tile‐drained field in Indiana, USA to study the impacts of surface and subsurface erosion on sediment leachate in heterogeneous preferential flow paths. Seven rainfall simulations were conducted to assess the impact of rainfall intensity on the leachate of surface eroded sediments (three events), and the impact of antecedent conditions on subsurface eroded sediments (four events). Cumulative sediment yield, linear mixed effects modelling, and hysteresis analyses were performed for all events. Results were presented in a series of four case studies. Results showed that surface sediment leachate concentration and yield were tightly linked to the filtration capacity of lysimeters, with more than 2/3rd of sediment originating from a single lysimeter, despite similar flow leachate volumes from each. Rainfall intensity significantly impacted the transport of surface eroded sediment at the highest intensity. Subsurface sediment erosion from undisturbed macropores was low compared to surface soils, but we found contrasting controls on sediment concentrations at low and high antecedent moistures that were equally important to sediment leachate yields. Disturbed macropores produced comparable sediment yields to surface erosion and behaved similarly to soil pipes in terms of erosion mechanics. Hysteresis results generally highlighted contrasting results for surface and subsurface sources but suggest that the prominence of slow flow, low‐concentration leachate sources can alter the interpretation of results in field‐scale applications. Our findings underscore an array of processes and pathways for sediment transport in the shallow vadose zone, and results will be useful for evaluating new model formulations.

Diffusion law and diffusion model for backfill grouting in loess shield tunnel at different soil moisture

Loess is a special type of soil whose properties are significantly affected by water. However, the grout diffusion law for backfill grouting in loess shield tunnels remains unknown. Based on a visual model experimental device, three experiments were conducted with 10%, 20%, and 30% loess moisture. A finite discrete element method was used to verify the grout diffusion mode, and parameters such as the tunnel buried depth, grout viscosity, and elastic modulus were considered to analyse the grout diffusion law. Experiments and numerical simulations show that the screening diffusion of grout occurs at low loess moisture, whereas splitting diffusion occurs at high loess moisture. The farthest splitting diffusion distance decreases as the tunnel buried depth, grout viscosity, and elastic modulus increase. In addition, based on capillary theory and geotechnical strength criteria, screening diffusion and splitting diffusion models were established. This study investigated the grout diffusion law and grout diffusion model, providing a reference for the design and construction of loess shield tunnels.

Molecular investigation of bamboo during stress relaxation using custom-built mechanical loading platform coupled with Raman spectroscopy

Bamboo holds significant potential as a substitute for plastics. Stress relaxation is a critical property during the fixation stage of plastic formation for bamboo products intended to replace plastic. However, research on this topic has been limited. In this study, a custom-built mechanical loading platform coupled with Raman spectroscopy was acquired during stress relaxation of bamboo under different humidity levels. Results reveal variations in stress relaxation patterns based on node position, radial location, and humidity, along with changes in cellulose molecules in response to these factors. Specifically, stress relaxation modulus in bamboo decreases from the outer to the inner part, increases in the presence of node structures, and decreases with increasing humidity. The shifts in Raman spectral bands exhibit significant changes in response to variations in stress and humidity. The elongation of cellulose chain bands at 1097 cm−1 in the Raman spectrum shows an increasing trend during stress relaxation, with larger band shifts observed at lower humidity. Simulations of cellulose molecular stretching show a stronger stress response at lower moisture content, with a maximum stress of 0.85 GPa for cellulose at 3.3 % moisture content, compared to 0.79 GPa at 7.8 % moisture content. These findings suggest a novel approach for the molecular investigation of materials during stress relaxation, which is crucial for the plasticity processing of bamboo.

The Optimal Moisture Content for Cryopreservation of Longjing Tea Seeds

BACKGROUND: Most plant species produce seeds that can be dried to c. 3-7% moisture content, i. e., orthodox, and successfully stored in liquid nitrogen. However, tea seeds are often described as 'recalcitrant', i. e., they die when to lower moisture levels safe for cry opreservation. OBJECTIVE: In this study, we investigated the tolerance to desiccation and freezing of Longjing tea (Camellia sinensis) seeds and analyzed the reason behind seed mortality during desiccation and cryopreservation. MATERIALS AND METHODS: We analyzed the desiccation capacity of tea seeds from Hangzhou, China and subjected the desiccated seeds to programmed cooling and thermal analysis using differential scanning calorimeter (DSC). Subsequently, we used the exotherms to determine the frozen and unfrozen water. We analyzed seed germination and seedling establishment at different water content after storing seeds in liquid nitrogen and correlated the survival with the bound and unbound water. RESULTS: Results showed that the seeds could tolerate drying to 7.9% moisture content without significant viability loss. Moreover, the germination percentage declined sharply after cryopreservation, and the lowest moisture content at which a normal seedling could develop was 11.3±1%, although seeds dried to lower MC did germinate but did not grow into the seedling phase. CONCLUSION: Longjing tea seeds used in this study were neither orthodox nor recalcitrant. We show that the interaction between lipids and freezable water in seeds may lead to the cryoinjury.

Aridity-Driven Change in Microbial Carbon Use Efficiency and Its Linkage to Soil Carbon Storage.

Global warming is generally predicted to increase aridity in drylands, while the effects of aridity changes on microbial carbon use efficiency (CUE) and its linkage to soil organic carbon (SOC) storage remain unresolved, limiting the accuracy of soil carbon dynamic predictions under changing climates. Here, by employing large-scale soil sampling from 50 sites along an ~6000 km aridity gradient in northern China, we report a significant decreasing trend in microbial CUE (ranging from approximately 0.07 to 0.59 across the aridity gradient) with increasing aridity. The negative effect of aridity on microbial CUE was further verified by an independent moisture manipulation experiment, which revealed that CUE was lower under lower moisture levels than under higher moisture levels. Aridity-induced increases in physicochemical protection or decreases in microbial diversity primarily mediated the decrease in CUE with increasing aridity. Moreover, we found a highly positive microbial CUE-SOC relationship, and incorporating CUE improved the explanatory power of SOC variations along the aridity gradient. Our findings provide empirical evidence for aridity-induced reductions in microbial CUE over a broad geographic scale and highlight that increasing aridity may be a crucial mechanism underlying SOC loss by suppressing the ability of soil microorganisms to sequester carbon.

Effect of pores and moisture on the mechanical properties of calcium silicate hydrate gels at mesoscale

Pores and moisture significantly influence the mechanical properties of cementitious materials. Investigating the effects of pores and moisture on the mechanical properties of calcium silicate hydrate (C-S-H) gels at the mesoscale is fundamental to understanding the multiscale behavior of these materials. In this study, mesoscopic models of C-S-H gels with varying porosities were developed using coarse-grained C-S-H nanoparticles. The potential function, describing the interaction between C-S-H nanoparticles under different humidity conditions, was derived based on the mechanical properties of C-S-H nanoparticles, the Lennard-Jones (LJ) potential, and capillary theory. Subsequently, simulations of uniaxial tensile, uniaxial compression, and shear experiments on C-S-H gels with different porosities and moisture levels were conducted. The influence of pores and moisture on the mechanical properties of C-S-H gels was analyzed using two-way analysis of variance (ANOVA) and then compared with mesoscopic influence patterns. The results showed that the mechanical properties of C-S-H gels decrease with increasing porosity and moisture at the mesoscale. And there is an interaction effect between gel pore porosity and moisture. The smaller the porosity, the more significant the weakening effect of increasing moisture on elastic parameters and strength. Conversely, the weakening effect of increasing porosity on elastic parameters and strength is more significant at lower moisture levels. The interaction between pores and moisture has a more pronounced effect on strength, which intensifies with increased moisture. The effect of porosity on the mechanical properties of C-S-H gels is consistent with macroscale studies. However, the effect of moisture on elastic parameters exhibits an opposite trend, attributed to the different mechanisms of water's influence at different scales.

Microencapsulation of Hibiscus sabdariffa extract in taro starch: Determination of optimal conditions of bioactive compound retention using response surface methodology

Hibiscus sabdariffa (HS) extract contains a large amount of bioactive compounds with antioxidant, anticarcinogenic, and antihypertensive effects. The extraction of total phenols, flavonoids, and anthocyanins is more efficient at boiling temperature (~91 °C) than that performed at room temperature (~27 °C). In this study, a central composite rotatable design (CCRD) was used to optimize the inlet temperature conditions of a spray dryer and the concentration of taro starch solids to obtain microcapsules with the highest retention of bioactive compounds in hibiscus extracts. Optimized microcapsules (OM) were obtained at an inlet temperature of 118 °C and solid concentration of 26.5 %. Low moisture content (4.54 %) and water activity (0.2) and high content of total phenols (3374.91 mg GAE/100 g), flavonoids (372.81 mg QE/100 g), monomeric anthocyanins (36.74 mg C-3-GE/100 g), and angiotensin-converting enzyme inhibitory activity (80.01 %), were determined in OM using response surface methodology. OM showed a range of spherical agglomerate sizes (10––32 μm). These results indicate that CCRD is a good tool for establishing the optimal conditions for solid concentration and drying temperature to maximize the protection of bioactive compounds using taro starch as the wall material.

Potential Utilisation of Solar-Assisted Kiln Dryer in Bamboo Drying

Bamboo is increasingly used as an alternative material for producing renewable and environmentally friendly products. Bamboo should be dried before use to increase its stability and improve its resistance against biodeterioration agents. The most common drying method for bamboo is through air-drying. Alternatively, artificial drying, such as solar drying, can produce optimum drying results regarding the drying rate and quality of bamboo throughput. This study investigated the potential utilisation of solar drying methods for processing local bamboo. The drying characteristics and physical and mechanical properties of solar-dried Gigantochloa levis bamboo culms’ bottom, middle, and top sections were determined. The drying time of G. levis culm has been reduced to about 40 days compared to the conventional air drying of 70 days using the solar-assisted kiln dryer. Solar-dried culms have a lower final moisture content of 20% than air-dried ones. The average circumference and diameter shrinkage values of solar-dried G. levis culms from green to approximately 12% moisture content were 3.22% and 4.29%, respectively, and the wall thickness shrinkage was 8.12%. The mean values of modulus of rupture and modulus of elasticity of solar-dried G. levis culm were 63.75 and 12567.99 N mm-2, respectively, while its mean values of compression and shear parallel to fibre were 45.87 and 10.01 N mm-2, respectively. The quality of solar-dried G. levis culms produced in this study showed the viability of using a solar-assisted kiln-dryer as a potential alternative processing method for drying local bamboo species in Malaysia.

Biochemical and morpho-physiological insights revealed low moisture stress adaptation mechanisms in cotton (Gossypium hirsutum L.)

Cotton (Gossypium hirsutum L.) is a multipurpose crop. Abiotic stresses, especially extreme heat and drought, limit crop growth and thus reduce cotton yield by about 50%. In this study, 30 cotton genotypes were tested against low moisture stress in a pot experiment in triplicates along with control under wire house conditions. At the 3–4 leaf stage, different morpho-physiological and biochemical parameters were measured in order to select the low moisture stress-tolerant genotypes. For the selection of the best performing genotypes, Multi-Trait Genotype-Ideotype Distance Index (MGIDI) was used for the ranking of genotypes on the basis of multiple indices. For biochemical traits, 09 (TPC, TF, TSP, MDA, SOD, POD, CAT, APX, and Proline) out of 24 showed significant genotypic effects and were used for MGIDI. Eight genotypes (N-812 N-1296 N-696 N-377 N-121–896 N-T86, and N-3496) were observed to be best performing than others at 25% selection pressure (SI = 25%). For morpho-physiological traits, 14 out of 15 showed significant genotypic effects and used for MGIDI. Ten genotypes (N-1237 N-812 N-1296 N-696 N-9078 N-377 N-512 N-121 N-375, and N-896) were observed to be best performing at 35% selection pressure (SI = 35%). Six genotypes, i.e. N-812–1296 N-696 N-377 N-121, and N-896 were found common in both MGIDI analysis. In conclusion, three genotypes, i.e. N-696, N-896, and N-T86 proved to be most resilient to low moisture stress. Develop protocols, identified genotypes and markers that can be used for development of climate-smart cotton genotypes.

Quantifying Residual Soil Moisture through Empirical Orthogonal Functions Analysis to Support Legume-Based Cropping Systems

AbstractThis study investigates spatiotemporal variability of residual soil moisture during the OND (October-November-December) season in Ethiopia and its implications for crop productivity. Employing advanced statistical techniques, we analyze spatial and temporal distribution of soil moisture across Ethiopia from 1981 to 2020, focusing on selected crops including legumes: chickpea, field peas, common bean, soybean and alfalfa, to assess the potential of residual moisture to support post-rainy season cropping. Results indicate pronounced east-west moisture gradients, with eastern regions of Ethiopia exhibiting lower moisture levels (&lt; 60 kg.m-2) compared to western regions (&gt; 150 kg.m-2). The central highlands, which are pivotal for agricultural activities, demonstrate significant variability in moisture (standard deviations &gt; 25 kg.m-2), with implications on agricultural sustainability. The northern and southeastern tips of the country are particularly vulnerable to prolonged drought, where climate change and frequent dry spells exacerbate moisture deficits, consequently impacting crop productivity. Despite these challenges, promising opportunities for future crop production emerge in the southeastern region, which is characterized by increasing moisture trend over time ($$\:\tau\:=0.59$$). Findings further indicate that residual moisture adequately meets and supports crop water requirements in the western, central, and southwestern Ethiopia. In these regions, residual moisture supports more than 90% of cropland water requirements of various crops during the initial and late-season growth stages, whereas water requirement coverage drops to less than 20% during the mid-season growth stage. Therefore, by utilizing residual soil moisture alongside supplemental irrigation, Ethiopian farmers can meet crop water needs for double cropping and enhance resilience to climate variability.

DNA profiling, nutritional value and phytochemical investigation of Cissus rotundifolia Lam. growing in Yemen

Cissus rotundifolia Lam. (Vitaceae) is a wild plant that is commonly used as food and medicine. There are limited studies on the phytochemical composition of this plant. So, this study aims to investigate C. rotundifolia growing in Yemen phytochemically. HPLC analysis of C. rotundifolia aerial parts led to the identification and quantification of four compounds (isoorientin, quercetrin, quercetin, and linarin), among which isoorientin and quercetrin were the major. Proximate analysis showed high fibre content and low moisture content, whereas the nutritional values showed a high carbohydrate content which gave rise to higher nutritional value (266.39 Kcal.). Potassium, calcium, iron, magnesium, and vitamin E were present in high concentrations. Investigation of the methylene chloride and n-butanol fractions lead to the isolation of seven compounds: β-sitosterol, magnificol, β-sitosterol-glucoside, quercetin, quercetrin, isoorientin, and linarin. This is the first report on isolating these compounds from the investigated plant.

New Eco-Friendly Thermal Insulation and Sound Absorption Composite Materials Derived from Waste Black Tea Bags and Date Palm Tree Surface Fibers

A tremendous amount of waste black tea bags (BTBs) and date palm surface fibers (DPSFs), at the end of their life cycle, end up in landfills, leading to increased pollution and an increase in the negative impact on the environment. Therefore, this study aims to utilize these normally wasted materials efficiently by developing new composite materials for thermal insulation and sound absorption. Five insulation composite boards were developed, two were bound (BTB or DPSF with polyvinyl Acetate resin (PVA)) and three were hybrids (BTB, DPSF, and resin). In addition, the loose raw waste materials (BTB and DPSF) were tested separately with no binder. Thermal conductivity and sound absorption coefficients were determined for all boards. Thermal stability analysis was reported for the components of the tea bag (string, label, and bag) and one of the composite hybrid boards. Mechanical properties of the boards such as flexural strain, flexural stress, and flexural elastic modulus were determined for the bound and hybrid composites. The results showed that the thermal conductivity coefficients for all the hybrid composite sample boards are less than 0.07 at the ambient temperature of 24 °C and they were enhanced as the BTB ratio was reduced in the hybrid composite boards. The noise reduction coefficient for bound and all hybrid composite samples is greater than 0.37. The composite samples are thermally stable up to 291 °C. Most composite samples have a high flexure modulus between 4.3 MPa and 10.5 MPa. The tea bag raw materials and the composite samples have a low moisture content below 2.25%. These output results seem promising and encouraging using such developed sample boards as eco-friendly thermal insulation and sound absorption and competing with the synthetic ones developed from petrochemicals in building insulation. Moreover, returning these waste materials to circulation and producing new eco-friendly composites can reduce the number of landfills, the level of environmental pollution, and the use of synthetic materials made from fossil resources.

Technological characterization of tropical woods from the genus Eperua (Fabaceae)

ABSTRACT In the Amazon basin, effective forest management plans are essential for sustainability, as they promote the exploration of new species. The Fabaceae family, which is abundant in tropical forests, includes tree species with timber potential, but gaps remain in understanding their properties. This study investigated the chemical and physicomechanical properties of Eperua from the Brazilian Amazon. Trees were randomly collected from native forests in Amazonas/Brazil. The samples were analyzed to determine their chemical and physicomechanical traits. The results revealed that Eperua falcata had high concentrations of extractives and lignin (15% and 27%, respectively), whereas Eperua leucantha and Eperua purpurea presented relatively high holocellulose contents, reaching up to 66%. The physicomechanical properties indicated a low moisture content (dry matter > 90%) and densities ranging from 620 to 900 kg m−3. All the samples had anisotropy values <1.8%. E. falcata and E. schomburgkiana presented the highest values for higher heating value, modulus of elasticity, rupture, and hardness. The analysis of the chemical composition, along with the physical and mechanical properties of the woods from the genus Eperua, reveals significant potential for applications in sustainable construction and high added-value products, particularly in sectors requiring durability and resistance, such as civil construction and furniture manufacturing.

Tribological properties and related effects of compressed, thermally modified and wax-impregnated wood

AbstractThis paper develops a process for the preparation of modified wood with low friction and low wear for tribological applications such as self-lubricating bearings. Two types of wood, beech (Fagus sylvatica) and robinia (Robinia pseudoacacia), have been studied and the results compared with naturally lubricated native lignum vitae. The process developed consists of plasticisation followed by compression in a mould, thermal modification and subsequent wax impregnation. Plasticisation was carried out by conditioning the samples to a low equilibrium moisture content of 10%, followed by heating to a sample core temperature of 80 °C. This process protects the internal wood structure from mechanical damage during densification. After plasticisation, the wood was compressed in a press mould. A low springback effect (SBE), resulting in compression of up to 40%, was achieved by unloading the mould without opening it. This step optimises compressive strength and hardness. Subsequent heat treatment reduces thickness swelling by up to 85%. Finally, a wax impregnation was applied to reduce friction. Sliding wear tests on modified beech wood have shown that the lowest wear occurs in the cross-sectional orientation (load perpendicular to the fibre ends; rxt orientation). Sliding friction studies using a steel ball on a ball-on-disc tribometer showed that compressed and thermally modified samples impregnated with rapeseed wax or beeswax exhibited coefficients of friction in a range of 0.08 to 0.09. These values are almost four times lower than those of plain compressed wood and even lower than those of lignum vitae, which was used for plain bearings decades ago. This study clearly demonstrates the high potential of compressed, thermally modified and wax-impregnated wood.