Low Bulk Density Research Articles

Colloidal-graphite suspension based on thermally expanded graphite

Currently, modified oxidized (intercalated) graphites and thermally expanded graphites obtained from them are used in solving many applied problems. This is due to the fact that while retaining all the properties of layered graphite compounds, split graphite particles have important new properties, such as ease of molding, low bulk density, and active interaction with the polymer matrix. However, the question of the mechanisms of expansion of oxidized graphite and the properties of thermally expanded graphite particles split into layers has not been sufficiently studied. The establishment of experimental patterns of expansion processes of graphite oxidized by acids contributes to the understanding of the set of stages of complex processes occurring during the expansion of graphite particles in a gas atmosphere and in polymer matrices. The purpose of the work was to synthesize a colloidal-graphite suspension based on thermally expanded graphite particles, to study the properties of suspensions and expansion processes of oxidized graphite during thermal and microwave heating. As a result of modifying thermally expanded graphite with low bulk density in activating media, colloidal graphite suspensions are synthesized without a vibration grinding stage. The splitting of graphite materials after chemical modification by thermal and microwave-stimulated heating leads to the formation of graphene-like structures. The development of techniques for modifying electrically conductive porous samples of materials used as electrodes makes it possible to introduce nanographite particles under the influence of an electric field.

Physical Properties and Compressive Strength of Pressed and Cast Fly Ash Geopolymer

Geopolymers are commonly recognized as sustainable alternatives to OPC and it has broad range of applications. Certain properties of geopolymer such as density are concerned in order to apply in the construction industry. Different densities of geopolymer could be obtained by varying the concentration of the alkaline activator. However, the densities do not differ much. Hence, a different production method of geopolymer can be applied. This study aimed to investigate the physical properties and compressive strength of pressed and cast fly ash geopolymer. The geopolymer samples were prepared by using pressing and casting method. Geopolymer samples without foam addition and with foam addition were prepared in order to achieve different densities of samples. The results demonstrated that the pressed sample has the highest bulk density (2285 kg/m3) whereas the cast sample with added highest ratio of foam has the lowest bulk density (1293 kg/m3). The apparent porosity and water absorption result were inversely proportional to the bulk density result. The densest geopolymer obtained the highest compressive strength (61 MPa) and the lightest geopolymer obtained the lowest compressive strength (7 MPa).

Effects of partial precipitation and freeze-drying on morphology and physicochemical properties of rice starch hydrolysates

Agricultural bio-catalysis is of immense scientific interest due to its increasing importance in the efforts for more sustainable agriculture while optimizing environmental impacts. In our studies, native rice starch was hydrolyzed with various alpha-amylase concentrations (0, 0.1, 0.2, and 0.3% w/w of starch) at 50°C for 20 min; then purified by partial precipitation (PP) with organic solvents, or freeze-drying (FD) without further purification. The rice starch hydrolysates (RSH) produced by different methods (PP or FD) were determined for dextrose equivalent (DE), morphology, and some physicochemical properties including bulk density, moisture content, hygroscopicity, and water solubility. The results showed that at the same alpha-amylase treatment conditions, the RSH obtained by the PP method had lower DE values and production yields than those of RSH obtained by FD method. The FD-RSH had higher DE values, lower bulk densities and moisture contents, higher hygroscopicity and water solubility. In morphology, the PP-RSH (DE 10.2) had a larger particle size and more condensed microstructure compared to the FD-RSH of almost similar DE 13.5. These findings showed that the PP method resulted in lower-DE RSH with different morphological and physicochemical properties compared to those obtained by the FD method.

Effect of rice hull amendment in green roof substrates

The use of waste and locally available materials could improve the sustainability of green roofs. Therefore, a study was conducted to evaluate the potential of a rice hulls in the organic and inorganic portion of green roof substrates. Three substrate mixtures were prepared at the site by mixing locally available materials. The substrate mixtures were designated as RPZV (rice hulls 6:1; pumice and zeolite mixture 2:1; vermicompost 2:1 by volume), PZR (rice hulls 2:1; pumice and zeolite 8:1), and PZV (pumice and zeolite 8:1; vermicompost 2:1). Measurements were performed including plant growth index, chlorophyll fluorescence, biomass accumulation on native and exotic plant species. Increased amounts of rice hulls in the substrate mixture had a significant effect on reducing bulk density up to 24%, increasing organic matter content up to 67% and maximum water holding capacity (WHC) of the substrate, but also had the lowest volumetric moisture values in the field measurements due to increased porosity and permeability of the substrate. Adversely, substrate mixtures with higher rice hull content experienced greater temperature fluctuations during the study period, which have resulted in increased plant mortality and stress for certain plant species during the study. As the organic part of the substrate, rice hulls caused a decrease on the salinity of the substrate by about 28% and provided higher survival rates and lower stress levels for A.schoenoprasum, C.creticus, L.spectabilis, D.chinensis and Sedum species. The results of the study suggested that, rice hulls may have the potential to be used in appropriate proportions due to their low bulk density, low salinity and resistance to degradation, leading to a reduction in the environmental impact of green roof construction.

Experimental investigation of fuel conversion characteristics during co-combustion of solid recovered fuel and coal in a 1 MWth circulating fluidized bed reactor

This study presents experimental results on co-combustion of hard coal and solid recovered fuel (SRF) conducted in a circulating fluidized bed (CFB) reactor with an internal diameter of 0.59 m, a height of 8.6 m, and a thermal load of 1 MWth. The high flexibility of the test facility enables testing of a variety of input materials under changing test conditions. The combustion of various fuel mixes ranging from 100 % hard coal to 100 % waste was tested to assess the impact of varying fuel ratios on the overall combustion process. As the proportion of SRF increased, a reduction in reactor differential pressure and particle density was observed. Moreover, combustion shifts to higher parts in the reactor when the share of SRF is increased. To further investigate the combustion conditions inside the reactor, three in-bed gas measurements were conducted, capturing the horizontal gas profiles of CO2, O2, and CO. An increase in SRF content led to elevated CO and O2 levels, alongside a reduction in CO2, indicating an upward shift in the combustion zone. The behavior is attributed to the higher volatile content of SRF, which is in this experiment roughly 2.5 times the share of volatiles in hard coal and the lower bulk density of SRF. The study concludes by proposing potential strategies for reducing the impact of high SRF content on combustion conditions.

Thermophysiological Comfort Behaviour of Cut Protective Workwear Consisting of Filament Twisted Multicomponent Hybrid Yarn

Current cut protective gear is subject to several difficulties, such as the use of heavy fabric, complicated donning processes, lack of comfort and limited movement. When selecting the most comfortable cut protective fabric, it is important to consider the end users' specific needs. The aim of this study was to enhance the comprehension and optimisation of protective apparel for superior occupational safety and protection by exploring the intricate link between material composition, yarn structure and comfort parameters. Various combinations of filament twisted core sheath yarn consisting of stainless-steel/glass with high-performance polyethylene and polyester wraps were used to fabricate thermo-physiological comfortable cut protective workwear fabric. Twelve cut protective fabrics with the same areal density (200 g/m2) were prepared with 6-end satin weave using filament twisted core sheath yarn of five distinct linear densities (98.4 tex, 73.8 tex, 59.1 tex, 49.2 tex and 39.4 tex). These fabric samples were used to evaluate thermophysiological characteristics, including air permeability, dry and evaporative heat resistance, thermal conductivity, moisture permeability, wettability and moisture wicking according to the established standard. The cut protection of each sample was also measured according to EN 13997. The cut protection and thermo-physiological comfort attributes of cut-resistant clothing are greatly influenced by the proportion of core material (stainless-steel/glass) and yarn structural parameters (linear density and twist direction), which was observed by analysing the results. An increased core material percentage (stainless-steel/glass) contributes to increased fabric thickness and reduced bulk density, which influences the thermophysiological comfort attributes of the developed cut protective workwear fabric. Fabric made from a higher proportion of core material (stainless-steel/glass) with a lower bulk density exhibited an acceptable cut protection level and performed better in terms of thermo-physiological comfort attributes.

Facile fabrication of lightweight and three-dimensional porous Dy2O3 decorated single-walled carbon nanotubes/reduced graphene oxide composite aerogels for broadband microwave absorption

Reduced graphene oxide aerogel (GA) has emerged as a promising microwave absorbing (MA) material. However, it remains a challenge for pure GA to achieve excellent MA performance owing to the limitation of loss model and impedance mismatching. Herein, a 0D@1D/2D construction of Dy2O3 decorated single-walled carbon nanotubes/reduced graphene oxide (Dy2O3@SWCNT/rGO) composite aerogel (DCGA) with high-performance electromagnetic wave (EMW) absorption was successfully obtained using a simple reduction self-assembly process. The DCGA features a distinctive 3D porous network formed by the stacking of lamellar rGO and has a low bulk density. As expected, the microwave attenuation performance of the DCGA exhibits a level of tunability that can be achieved by varying the mass ratio of GO along with Dy2O3@SWCNT. Benefiting from synergistic effect, the resulted ultralight DCGA-3 (4.6 mg/cm−3) exhibits a strong reflection loss (RL) of −57.6 dB (3 mm) at 13 GHz and a low filler loading ratio of ca. 1.4 wt%. Further, the maximal effective absorption bandwidth (EAB) (RL < −10 dB) of DCGA-1 can reach 7.8 GHz (10.2–18 GHz) with a thickness of 2.8 mm. Notably, the EAB of DCGA can completely cover X band and Ku band by adjusting the thickness. The excellent EMW absorbing ability was originated from the combined influence of optimized impedance matching, a distinctive multidimensional porous structure, a leaf-like conductive network and the presence of numerous defects and interfaces. Consequently, this research may aid in the development of graphene-infused hybrid composites featuring a 3D porous architecture, serving as lightweight and efficient absorbers of EMWs.

Comparison of technological and physical properties of matcha powders of different geographical origins.

The sorption characteristics and glass transition temperature are important attributes that determine the shelf life of foods, particularly in powder form, whereas color is a key factor influencing consumer acceptance. As the popularity of matcha green tea powder is increasing, this study investigated whether the country of origin of examples of matcha products available on the Polish market influenced the sorption properties, glass transition temperature, and color. All matcha powders exhibited sigmoidal water adsorption isotherms at 25 °C. The monolayer moisture content corresponding to the point of maximum stability ranged from 0.045 to 0.053 g water per g of sample. The glass transition temperature of anhydrous matcha powders varied between 106.3 and 139.0 °C. Based on the sorption and glass transition results, the matcha from Brazil should be the most stable during storage. The same sample showed the highest water solubility index values at temperatures above 80 °C and the lowest bulk density. The color parameters (L*, a*, b*, C*, and h) depended on the matcha powder variant. The results indicate that the optimal storage conditions for tea powders do not depend directly on the country of origin. Further research should therefore focus on analyzing the impact of climate or fertilization. © 2024 Society of Chemical Industry.

Calculating the effect of intensive use of urban organic waste on soil concentrations of potentially toxic elements in a peri-urban agriculture context in Norway

BackgroundRecycling nutrients and organic matter available as waste in urban areas may close nutrient gaps and improve soil quality, but the concentrations of potentially toxic elements (PTEs) are commonly higher than in mineral fertilisers. How quickly may the limits for soil quality be exceeded, and for which elements, if such materials are applied intensively? For a rough answer to this question, we used soil data from ten case farms near Oslo and Bergen (Norway) to estimate how PTE concentrations increased when the demand for nitrogen (N), phosphorus (P) and potassium (K) in a theoretical carrot crop produced every year was covered by compost or digestate from source-separated food waste, or composted garden waste, compared with manure from horses and poultry which are often kept in peri-urban areas.ResultsWith the intensive fertilisation assumed here, the Norwegian soil quality limits for PTEs were reached within 20–85 years, and faster for soil with more organic matter since regulatory limits set by weight discriminate soils with low bulk density. The limits were reached first for Cu and Zn, which are both essential micronutrients for crop plants. The concentrations of macronutrients in the urban waste-based fertilisers were not well balanced. Rates covering the K demand would lead to high surpluses of P and N. In peri-urban vegetable growing, high applications of compost are not unusual, but more balanced fertilisation is required.ConclusionsThe Norwegian regulations for PTEs in organic soil amendments and agricultural soil are stricter than in the EU, and do not support recycling of organic matter and nutrients from urban waste. Many materials which can only be applied with restricted amounts to Norwegian agricultural soil, may be applied according to crop demand in the EU. Growers utilising urban waste-based fertilisers intensively should monitor the soil regularly, including PTE analyses. Soil sampling should occur on fixed sampling points to reveal changes in concentrations over time. Norwegian authorities should consider a revision of the organic fertiliser regulation to support recycling of valuable organic materials. There is a need for more data on the PTE concentrations in agricultural soil and organic fertiliser materials.

Facile fabrication of sulfonated bacterial cellulose-silane composite aerogels via in suit polymerization for enhanced oil/water separation performance

Cellulose-based aerogels have emerged as highly promising materials for oil-water separation because of their highly porous nature, low bulk density, cost-effectiveness, and functional performance. In this study, a novel, robust, and hydrophobic bacterial cellulose aerogel (HBCA) was reported for highly efficient oil/water separation, which was formed by incorporating methyltrimethoxysilane (MTMS) into sulfonated nano-fibrillated bacterial cellulose (SNBC) matrix through freeze-drying method. The structural integrity of the SNBC/MTMS aerogel was ensured by its three-dimensional linked network structure. The resultant aerogel demonstrated superior hydrophobicity with a contact angle of 152.4°. As an oil-absorbing material, it selectively adsorbed different types of oils and organic solvents, with a saturation adsorption capacity ranging from 42.14 to 85.37 g·g−1. Additionally, this composite aerogel demonstrated outstanding separation efficiency (98.48 %) in continuous oil-water mixture processes, suggesting promising potential applications in the treatment of industrial oil pollution and oil spill accidents. This study indicates that the proposed HBCA with sulfonated nano-fibrillated bacterial cellulose is a potential and effective material for addressing environmental challenges related to oil contamination.

THE EFFECT OF HEAT-TREATMENT ON THE MECHANICAL PROPERTIES OF EXPANDED GLASS PARTICLE/A356 SYNTACTIC FOAM

This research investigates the manufacturing of metal syntactic foams (MSFs) using a packed bed of porous (2-2.8 mm) expanded glass (EG) within an A356 alloy matrix. To this end, the counter-gravity infiltration casting technique is employed to manufacture the specimens. The density of the MSFs ranges from 1.05 to 1.17 g/cm3, making it one of the lowest densities foams, attributed to the filler particles' low bulk density. The study investigates the influence of T6 heat treatment on the mechanical properties and microstructural characteristics of the manufactured MSFs. The mechanical properties of the MSFs are characterized under quasi-static compressive loads at 1 mm/min. After heat treatment, the compression test results indicate a significant enhancement in most mechanical properties. Compression strength and plateau stress are approximately doubled compared to as-cast foams for samples with similar densities. While energy absorption of the MSFs triples in heat-treated conditions. These improvements are attributed to changes in the matrix microstructure due to thermal treatment. Microstructural analysis reveals that Si particles, initially sharp and continuous within inter-dendritic boundaries, become blurry and discontinuous through spheroidization after thermal treatment. This hinders crack growth in the cell wall and mitigates the effects of casting defects and the columnar dendritic structure. The majority of mechanical properties in both heat-treated (HT) and as-cast (AC) foams exhibited an increase in density due to an increase in the matrix fraction. However, plateau end strain and energy absorption efficiency demonstrated an independent effect of heat treatment and density.

Effects of cover crop on selected abiotic and biotic soil health indicators

Current cropping systems, like cover cropping, aim to improve soil health and crop productivity, with the former a more sustainable route to the latter. This can be done by evaluating the influence of cover crops (CCs) on soil health indicators, both abiotic and biotic, as is the objective of this study. Several CCs (crimson clover [Trifolium incarnatum L.], oats [Avena sativa], hairy vetch [Vicia villosa Roth.], winter wheat [Triticum aestivum L.], winter peas [Lathyrus hirsutus L.], flax [Linum usitassimum L.], triticale [Triticale hexaploide Lart.], cereal rye [Secale cereale], and barley [Hordeum vulgare L.]) were used across two research sites, set up using a completely randomized design with two levels of CCs (CC vs no cover crop [NC]) and three replicates during 2023. Soil samples were collected at 0–10, 10–20, and 20–30 cm depths and analyzed for soil physico-chemical properties and microbial biomass and composition. Results showed significantly lower bulk density values, greater water content (at 0 kPa soil water matric potential), greater volume-specific heat capacity (at 0 and -33 kPa soil water matric potential), greater total nitrogen, and numerically greater soil organic carbon under CC compared with NC management. This led to numerically greater microbial biomass and community composition (e.g., arbuscular mycorrhizal fungi, gram-negative and gram-positive bacteria, eukaryotes, and fungi), and slightly lower microbial stress indicators (genotypic and chemical structure categorizations) under CC compared with NC management. However, the lack of significant differences between treatments suggests that three years is insufficient to detect improvements in measured soil health indicators. Further, the significant differences in measured soil health indicators between study sites suggests an influence of soil texture and order, and this warrants further investigations.

Review of Modelling the Compaction of High Aspect Ratio AgriculturalFeedstock Materials

Agriculture feedstock materials have low bulk density and are difficult to handle and transport. Compaction can enhance the agricultural feedstock density and could be an effective solution for handling problems. To develop a better compaction process, mathematical modelling can help understand the compaction mechanism and can help predict the mechanical behaviour of feedstock materials. This paper presents a review on the energy consumption, applied pressure, as well as rheological models to predict their compaction behaviour and thus help improve compacts’ mechanical strength and reduce densification costs. In summary, energy requirement for densification of biomass depends primarily upon the pressure applied, holding on time and properties of the material. From the published literature, it could be found that the Cooper-Eaton and the Kawakita-Ludde models that considers particle rearrangement and deformation mechanism can fit pressure and density of feedstock materials during compaction. The parameters in the rheological models were correlated to the properties of the feedstock materials and can be used for optimization of machine and operational parameters.

Material Characteristics of Compressed Dry Masonry Made of Medium-Size Elements with Perlite Aggregate.

Dry masonry is a type of construction that is nowadays used to a limited extent in the construction sector, including the housing sector. A lack of codified computational methods enabling engineers to design consciously is one of the factors limiting the development of dry walls. This article presents results from testing an innovative solution for dry masonry made of medium-size elements with expanded perlite aggregate. Material with this type of aggregate has a low bulk density (390 ± 10% kg/m3), which allows the production of large blocks and significantly reduces the value of the thermal conductivity coefficient λ = 0.084 ± 0.003 W/m·K. The results obtained were used to determine material parameters for designing a structure mainly exposed to vertical load. The important practical significance of the presented research results from the lack of provisions, specifications or standards allowing for the design, calculation and construction of dry masonry; it is not possible to analyse the behaviour of this type of structure and to design it consciously and safely. The presented research is therefore an important source of information on mechanical parameters essential for the design of structures and provides tools for this. As a result of the tests of nine panels, the mean compressive strength was determined (1.085 N/mm2), and then the procedure of "design assisted by testing" implemented into Eurocode was used to determine characteristic (0.873 N/mm2) and design compressive strength (0.565 N/mm2). Using the relationships σ-ε, an attempt was made to identify material models for the linear and non-linear analysis of the structure and for designing cross-sections. The material models were made considering increased non-linear deformations of a structure under low stresses (the compression toe) which are true and typical for dry masonry. A specific deformability of dry masonry, slightly different to that in masonry structures joined together with mortar, also affects the reduction factor for load-bearing capacity due to second-order effects. Reduction factors determined from true non-linear deformations were lower than the values specified by EC6 for masonry structures.

The Effect of Varying Compaction Levels on Soil Dynamic Properties and the Growth of Canola (Brassica napus L.)

Extremely low field emergence rates for canola are primarily attributed to soil compaction from field traffic during and after planting. This study aimed to determine the critical compaction level for canola emergence across different soil types. A laboratory experiment was conducted using sandy loam, silt clay, and clay soils, compacted to five levels (zero to four) using Proctor hammer drops after sowing canola (Brassica napus L.). The lab results were validated through two years of field experiments in sandy loam, applying four compaction levels (zero to three) using a tractor. Soil properties (bulk density and surface resistance) and canola growth parameters (plant emergence rate, count, height, and above-ground biomass) were measured. Zero compaction resulted in lower bulk density and surface resistance across all soil types. Laboratory results showed maximum emergence rates of 95% for sandy loam, 100% for silt clay, and 60% for clay, while field emergence rates were 63% and 87.59% in the first and second years, respectively, both at zero compaction. Recommendations include light or no compaction for sandy loam, and zero compaction for silt clay, while clay soil did not achieve the 80% emergence target at any compaction level. These results can assist agricultural producers in optimizing their seeding equipment setup and managing field traffic for canola production.

Fabrication of SiC-Al2O3 foam ceramic and its application in fluoride-containing water

Silicon carbide (SiC) foam ceramics demonstrate excellent filtration efficiency as filter supports due to their complex pore network and chemical stability. However, their fabrication demands high sintering temperatures (above 2100 °C), resulting in substantial energy consumption and production costs, which restricts their wider use in separation and purification application processes. To address this, we utilized fly ash, a by-product of coal combustion rich in inorganic Al₂O₃, as a sintering aid to develop a porous silicon carbide–alumina foam ceramic (SAFC) and investigated the effects of Al₂O₃ on its performance. Additionally, we introduced SAFC as an adsorbent material, synthesizing the fluoride adsorbent (La@SAFC) and evaluating its fluoride removal efficacy through batch experiments. Results indicate that Al₂O₃, as a sintering aid, promotes the sintering process by forming a liquid phase that enhances Si and C diffusion at lower sintering temperatures. SAFC containing 16 wt.% Al₂O₃ achieved optimal porosity, low bulk density, and compressive strength at a sintering temperature of 1150 °C. The addition of Al₂O₃ also facilitated mullite formation, significantly enhancing the ceramic's mechanical properties. However, excess Al₂O₃ can produce an overabundant liquid phase and gas release, potentially compromising the mechanical integrity of SAFC. Batch experiments revealed that La@SAFC exhibited strong fluoride removal from water containing competing ions across a pH range of 3–7, achieving effluent within strict discharge standards. Mechanism analysis suggested fluoride removal via ion exchange and electrostatic interaction. La@SAFC maintained high fluoride removal efficiency across five regeneration cycles, underscoring its promise for practical applications.

Do Cover Crops Influence In Situ Soil Water Potential After Termination?

Soil water movement is energy-dependent and is influenced by various management practices. It can be understood by measuring the soil water potential (SWP); however, the influence of cover crops (CCs) on SWP is not currently well understood. The objective of this study was to assess the effects of CCs on SWP before and after termination in order to understand their effects on soil water availability for the subsequent cash crop. The experimental design was a completely randomized design with two levels of CCs (CCs vs. no cover crop [NC]) with three replicates. The SWP sensors were buried at 0–10, 10–20, and 20–30 cm depths before CCs were planted. Additionally, soil samples were collected at the aforementioned depths just before CC termination for soil organic carbon (SOC), bulk density (BD), and saturated hydraulic conductivity (Ksat) analysis. Results showed that CCs increased SOC and Ksat, and significantly lowered BD compared with NC management. Before termination, CC plots had significantly lower SWP values compared with NC management, suggesting that the transpirational needs of the CCs can lead to lower water content. After termination, CC management also resulted in lower SWP, suggesting that CCs can increase water-use efficiency by improving soil health parameters. However, effective planning is required for CC implementation, especially in semiarid and arid regions.

Smoldering Ignition and Transition to Flaming Combustion of Pine Needle Fuel Beds: Effects of Bulk Density and Heat Supply

The smoldering of pine needle fuel beds (PNBs) has been a common subject of research because of its importance in initiating the rekindling of forest floor fires. Experimental studies of the coupling effects of the bulk density and external heat supply on smoldering in PNBs have been scarce up to now. In this study, laboratory smoldering experiments were conducted to study the coupling effects of bulk density (30–55 kg m−3) and heat supply (ignition-off temperature Toff = 190 °C and 230 °C). Different ignition modes were observed under the same conditions, including non- ignition (NI), flaming ignition (FI), and the smoldering-to-flaming (StF) transition. The results in this study showed that the bulk density had distinct effects on different ignition modes: the increase in the bulk density facilitated the StF transition but impeded the FI. The coupling effects between the bulk density and heat supply became more intricate, especially at lower bulk densities and at a reduced heat supply. Additionally, a simple energy balance equation was established to explain the coupling effects of bulk density and heat supply on ignition behavior. The critical mass loss rate (MLR) for the StF transition ranged from 0.01 g s−1 to 0.03 g s−1, while the critical MLR for FI was 0.035 g s−1. The modified combustion efficiency (MCE) index for the StF transition decreased from approximately 79.6% to 70.1% as the density increased from 30 kg m−3 to 55 kg m−3. In contrast, the MCE for FI was approximately 90% across all the bulk densities. The StF transition delay time increased from 50 s at 30 kg m−3 to 1296 s at 55 kg m−3 when Toff = 230 °C. Further reduction in heat supply led to an increase in the delay time for the StF transition by diminishing the intensity of smoldering combustion. This work advances the fundamental understanding of how heat supply and bulk density impact smoldering ignition modes, ultimately aiding in the development of wildfire prevention strategies.

Paddy straw biochar amended sediment enhances pond productivity, growth and physiological profile of Penaeus vannamei cultured in inland saline nursery ponds.

The growing interest in commercial Inland saline aquaculture has taken momentum across the globe due to the available technologies for aquaculture and the abundant resources of saline groundwater. However, the critical problems in inland saline ponds are degraded soil and imbalanced or deficient nutrients. To address these issues, a 75-day experiment was conducted to explore the effects of Paddy Straw Biochar (PSB) as a sediment amendment on sediment quality, water characteristics, growth parameters, and the well-being of Penaeus vannamei reared in inland saline environments. PSB was applied to the nursery ponds at 1 ton/hectare (Treatment, T1) and 2 ton/hectare (Treatment, T2). The findings of water quality parameters showed a significant increase in K+ and Mg++ with a decrease in ammonia-N levels in biochar-applied ponds. Similarly, the addition of biochar to ponds (T2) resulted in improved sediment characteristics with enhanced water holding capacity (24.75%), increased soil organic carbon content (77.94%), pH levels (0.37 units), cation exchange capacity (43.15%), available potassium (16.3%), and lower bulk density (12.61%) compared to ponds subjected to control conditions at the end of the experiment. Over the experiment, improvements in sediment and water quality parameters followed the T2 > T1 > control trend. Growth characteristics showed a significant rise in the percentage of weight gain (12.398 ± 0.12), SGR (11.80 ± 0.01% day-1) and PER (2.39 ± 0.01) with reduced FCR (1.19 ± 0.00) in biochar-treated ponds (T2), followed by T1 and control. The digestive enzyme activity (amylase) and metabolic enzymes like hepatopancreatic alanine aminotransferase (ALT) and muscle ALT activities were significantly higher in shrimps raised in the biochar-applied ponds. On the other hand, the oxidative stress enzyme superoxide dismutase (SOD) in gills, muscles, and hepatopancreas (HP) exhibited lower values, suggesting reduced oxidative stress due to the biochar amendment of the pond sediment. Overall, the study recommends incorporating PSB at a rate of 2 t/ha into nursery pond sediment to enhance water quality, physiological status, and the growth of P. vannamei juveniles. Moreover, this approach improves soil and water characteristics in saline soils, making it an effective culture practice in degraded environments.

Improving seedling recruitment and dryland restoration using a targeted fungicide seed coating

The success of seeding projects in dryland systems is sporadic, with failure primarily driven by low seedling emergence and survival. This sporadic nature is influenced by a litany of biotic and abiotic factors that act in synergy to reduce recruitment success. These factors include erratic seasonal weather patterns, competition, predation, plant material selection, and restoration strategies. While some events are unpredictable and uncontrollable, others may be mitigated through thoughtful deliberation. Pathogenesis from soil‐ and seed‐borne fungi is one form of predation that can decrease restoration success. Fungicide seed coatings are technologies used in the agriculture industry to mitigate fungal pathogens, yet these technologies are novel to wildland seeding. We evaluated the ability of a fungicide seed coating to improve bluebunch wheatgrass (Pseudoroegneria spicata) recruitment across a broad range of sites and determined how soil and climate affected seed treatments across six sites over 650 linear kilometers of sagebrush‐steppe habitat in the Great Basin, United States. Treatment effects varied by site; however, on average, the fungicide treatment increased germination by 16%, emergence by 42%, and juvenile plant establishment by 60%. Fungicide seed treatments had a greater effect on seedling emergence in soils with lower pH, reduced wet‐thermal accumulation during the winter, lower bulk density, and higher organic matter content. Most notably, the fungicide seed treatment resulted in higher plant establishment when emerged seedlings were exposed to longer periods of available soil moisture. Fungicide seed treatments can improve the establishment of native bunchgrasses, when soil and climate regimes are considered.