Higher Bulk Density Research Articles

Evaluation of Morphological, Physical and Functional Attributes of Agathi (Sesbania grandiflora) Leaves and Flowers

The study aimed to characterize the morphological, physical, and functional properties of agathi (Sesbania grandiflora) leaf and flower powders, highlighting their potential for food applications. Morphological assessments revealed that agathi leaves have an edible index of 76.20 ± 0.42 % and a waste index of 23.75 ± 0.65 %, while flowers showed an edible index of 63.79 ± 0.46% and a waste index of 36.21 ± 0.54 %. Physical properties showed that leaf powder had a higher bulk density (0.36 ± 0.02 g/cm³) and tapped density (0.59 ± 0.02 g/cm³) compared to flower powder (0.29 ± 0.03 g/cm³ and 0.48 ± 0.01 g/cm³, respectively). The flowability (Carr index) was slightly better for flower powder (40.24 ± 0.01 %) than for leaf powder (39.2 ± 0.01 %). Functional properties indicated that flower powder had significantly higher water absorption capacity (597.28 ± 1.22 %) and oil absorption capacity (224.21 ± 1.56%) compared to leaf powder (315.30 ± 1.28 % and 183.16 ± 1.34 %, respectively). Flower powder also exhibited greater solubility (28.77 ± 2.66 %) versus leaf powder (12.92 ± 1.59 %). These results suggest that both agathi powders are valuable ingredients for food formulations, providing functional and nutritional benefits, and are suitable for use in developing, handling, and packaging functional food products.

Study on recrystallization process of nitroguanidine by directly adding cold water to control temperature

Abstract Nitroguanidine (NGu), as a kind of high-energy material, is widely used as explosive propellant and energy component of explosives and smokeless powder. However, NGu crystals prepared by crystallization process are hollow and long needles, and their bulk density and bombing performance are greatly limited due to the high energy density at the tip, large porosity, and poor fluidity. Surprisingly, the particle size and morphology of NGu can effectively be improved by the recrystallization process. In this article, the recrystallization process by directly adding cold water to control temperature is first proposed, aiming to improve the morphological characteristics and reduce the particle size of NGu. Through single factor experimental research, the influences of various operating parameters on the morphology and particle size of NGu during recrystallization process were studied in detail. The results showed that the smallest average particle size of NGu was 19.8 μm when the crude NGu concentration, cold water temperature, volume ratio of boiling to cold water, stirring speed, and polyvinyl alcohol concentration were 5 g/100 mL, 0°C, 1:1, 800 rpm, and 0.35 g/100 mL, respectively. Correspondingly, the morphology of NGu was short rod, which was helpful to improve the bulk density. This novel recrystallization process has great potential to improve the NGu morphological characteristics, providing a new idea for the preparation of military NGu with small particle size and high bulk density.

Estimating the snow density using collocated Parsivel and Micro-Rain Radar measurements: a preliminary study from ICE-POP 2017/2018

Abstract. A new method is developed to derive the bulk density and bulk water fraction of a population of particles from collocated measurements from the Micro-Rain Radar (MRR) and Particle Size and Velocity disdrometer (Parsivel). A rigorous particle-scattering simulation, namely the T-matrix method, is applied to Parsivel's particle size distribution data to calculate the reflectivity (ZHH). The possible combinations of the particle's ice, air, and water are derived to compare them with the MRR-measured ZHH. The combination of the minimum water fraction and maximum ice fraction subsequently determines the bulk density (ρbulk). The proposed method is applied to the data collected from the International Collaborative Experiments for Pyeongchang 2018 Olympic and Paralympic winter games (ICE-POP 2018) projects and its pre-campaign. The estimated ρbulk was examined independently by a comparison of the liquid-equivalent snowfall rate (SR) of collocated Pluvio devices. The bias values are adequately low (SR: −0.25–0.06 mm h−1). The retrieved bulk density also shows good consistency with collocated Precipitation Imaging Package (PIP) retrievals. The results indicate the capability of the proposed algorithm to derive reliable ρbulk, leveraging the compact and easily deployable designs of MRR and Parsivel. The derived bulk density of the two warm–low cases (28 February and 7 March 2018) shares a similar transition as the systems were decaying. The higher bulk density and bulk water fraction were found in the coastal sites (BKC and GWU have a median value of ρbulk and are 0.05 to 0.12 g cm−3), typically accompanied by higher liquid-water constituents (mean values of the top 5 % bulk water fraction are 0.07 to 0.45) than the inland sites (YPO and MHS have a median value of ρbulk and are 0.06 to 0.10, and mean values of the top 5 % bulk water fraction are 0.001 to 0.008) during such synoptic conditions.

Annual soil erosion characteristics of unpaved roads in the Loess Plateau hilly and gully region, China

The problem of unpaved road erosion is prominent in the Loess Plateau hilly and gully region. Unpaved roads contribute substantially to watershed sediment due to their high soil bulk density, low infiltration rates and extensive network. In this study, a field investigation was conducted on typical unpaved roads within a typical watershed in this region, focusing on assessing the damage state, annual soil loss and the factors influencing erosion in a comparatively wet year. The results showed that the soil erosion from unpaved roads was very severe, with an annual erosion intensity of 470 t hm−2, following three heavy rain events and two rainstorm events in the summer of 2022. The main unpaved roads (MUR) suffered the most severe road erosion, with 22.2 % of road segments experiencing severe erosion with classical gullies. The erosion gullies on the road had an average depth of 16.1 cm and an average width of 36.5 cm, with the widest being 146.0 cm and the deepest being 174.0 cm. The road erosion intensity was significantly related to drainage area, road area, road length and coverage. Road erosion reduced significantly when the land use in the drainage areas of the road was covered with shrub or grass, or road surface was covered with grass or gravel. Our findings offer valuable insights for road construction and erosion prevention in similar terrains.

Responses of soil properties and foliar traits of a dominant tree species Pseudotsuga sinensis to rocky desertification in a karst ecosystem

Rocky desertification is a prevalent environmental challenge across karst landscapes that hinders regional sustainable development. Understanding how soil properties and plant traits respond to increasing levels of rocky desertification is crucial for developing effective restoration strategies. Here, we investigated soil characteristics and intraspecific leaf stoichiometric traits of Pseudotsuga sinensis across a gradient of rocky desertification in a karst ecosystem. We employed principal component analysis to assess changes in soil properties and leaf chemical traits and used leaf trait network analysis to explore shifts in trait network topology. Our results revealed that severe desertification sites had soil with high bulk density and pH, and low levels of available nitrogen, phosphorus, magnesium, as well as soil organic carbon. Leaf stoichiometry shifted markedly along the gradient, with elevated nitrogen limitation and cation imbalance in degraded sites. Trait network analysis showed that network diameter and modularity increased while connectance decreased with rocky desertification, indicating reduced integration among traits. On the other hand, higher adaptation capacity to environmental harshness under moderate level of rocky desertification was also observed. These findings suggest that both soil properties and leaf traits would experience substantial shifts across rocky desertification gradient, with increasing functional fragmentation and nutrient limitation as degradation intensifies. Based on our results, we propose management strategies targeted to different levels of rocky desertification to mitigate its negative impacts and promote ecosystem recovery.

The emission of pollutants from ornamental shrubs during forest fires

AbstractThis study investigates the combustion behavior, emissions, and aerosol production of four plant species: Laurus nobilis, Cistus monspeliensis, Photinia fraseri, and Cupressus sempervirens. The Heat Release Rate (HRR) and Smoke Production Rate (SPR) were measured, revealing that Cupressus sempervirens had the highest HRR and longest flame duration due to its higher bulk density. Emission Factors (EFs) for key compounds such as CO₂, CO, NO, and aerosols showed significant variation by species. Aerosol analysis indicated that the combustion of all plants primarily emitted fine particles, with the majority being ultrafine particles (PM0.1), particularly in the 25–130‐nm range. Particle size distributions were bimodal in number but monomodal in volume. These findings highlight the impact of plant characteristics on fire behavior and emissions, with significant implications for understanding fire dynamics in wildland–urban interfaces.

Effects of Different Weeding Methods on Soil Physicochemical Properties, Root Morphology, and Fruit Economic Traits in Camellia oleifera Abel. Plantations

Soil physicochemical properties, root characteristics, and fruit economic traits were determined in Camellia oleifera plantations under spontaneous vegetation + mowing (W1), spontaneous vegetation + glyphosate (W2), and no weeding (CK) treatments. Compared with CK, W1 reduced soil bulk density and increased total nitrogen, total phosphorus, ammonium nitrogen, nitrate nitrogen, and effective potassium content. W2 treatment resulted in higher bulk density than W1 and lower water-holding capacity, total nitrogen, total phosphorus, total potassium, ammonium nitrogen, nitrate nitrogen, and available potassium of the soil. Generally, both W1 and W2 inhibited weed morphological traits while favoring the C. oleifera root system, with the W1 treatment resulting in the greatest increase. Fruit transverse diameter, longitudinal diameter, yield, and oil yield were higher in W1 than in CK and W2 treatments. Weed root systems and C. oleifera root systems ultimately affect oil production and yield by affecting bulk density, ammonium nitrogen, nitrate nitrogen, fruit transverse diameter, seed yield, and seed kernel oil content. In summary, W1 treatment improved the physicochemical properties, root growth, fruit growth, and soil quality in C. oleifera plantations.

Effect of Plow Pan on the Redistribution Dynamics of Water and Nutrient Transport in Soils

Plow pans are an essential part of the agricultural soil structure. By adjusting the soil bulk density and plow pan height, the water and nutrient transport are dynamically redistributed. Plow pans play a crucial role in promoting crop growth, increasing yields, and supporting sustainable land management. In this study, a column experiment was conducted to investigate the effects of plow pan height (10 cm and 15 cm) and bulk density (1.2, 1.4, and 1.6 g cm⁻3) on soil nutrient and water leaching under high-volume (HV) and low-volume (LV) fertilizer applications. The results reveal that the leachate volume decreased by 61.9% at a plow pan height of 10 cm and by 96.2% at a plow pan height of 15 cm when the bulk density was increased from 1.2 to 1.4 g cm⁻3 under HV conditions. There was no leachate when the plow pan bulk density was 1.6 g cm−3. The reserved concentration of alkali-hydrolyzable N in the plow pan soils was the highest when the plow pan had a bulk density of 1.4 g cm−3 and a height of 15 cm. However, when the plow pan height was 15 cm, the available P content in the plow pan soils decreased by 27.0% and 21.0% at bulk densities of 1.4 g cm⁻3 and 1.6 g cm⁻3, respectively, when compared with 1.2 g cm⁻3. Furthermore, the available P concentrations in the plow pan and subsoil layers decreased with an increase in the plow pan height. The available K concentrations in the topsoil decreased by 26.8% and 24.0% when the plow pan bulk density was increased from 1.2 to 1.4 g cm−3 at heights of 10 and 15 cm, respectively. Thus, the optimal plow pan height and bulk density are closely related to the types of soil nutrients. However, it is clear that excessively high bulk densities (e.g., 1.6 g cm−3) negatively impact soil properties. For different nutrient requirements, a bulk density of 1.2 or 1.4 g cm−3 can be chosen, with each providing suitable options based on the specific nutrient needs. This research offers practical insights into changes in nutrient adsorption and fixation in agricultural production associated with alterations in plow pan bulk density.

Effect of metakaolin and lime addition on geopolymerization of construction and demolition waste.

Construction and demolition waste generates the largest amount of waste by volume, which threatens sustainable development and adversely affects the environment. These wastes contain a significant amount of aluminosilicates that have the potential to be used as building materials for value-added applications applicable to alternative construction materials. This study aims to synthesize geopolymers from brick powder using metakaolin/lime as additives and compare their physico-mechanical properties. The compressive strengths of the geopolymer products GP-1, GP-2, and GP-3 developed at 28days from brick powder and metakaolin/lime with the activator solution were found to be 8.35, 21.30, and 25.0MPa respectively, 2.55 and 2.99 times higher when metakaolin and lime were added. FTIR spectra and SEM-EDX micrographs of the reaction products showed structural changes and formation of aluminosilicate hydrate and calcium silicate hydrate gel with Al2O3/Na2O ratios of 0.75, 1.67, and 1.98 respectively. The reaction products containing SiO2/(SiO2 + Al2O3 + Fe2O3) ratios of 0.70 and 0.76 were found to be desirable. The geopolymer product GP-3 was found to have a higher bulk density and mechanical strength than those of GP-1 and GP-2. These products are found to be very hard, with potential applications in construction industries to conserve the environment.

The Usability of Metallurgical Production Waste as a Siliceous Component in Autoclaved Aerated Concrete Technology

The reconstruction of buildings is a complex process that often requires the consideration of the construction load when selecting correct building materials. Autoclaved aerated concrete (AAC)—which has a lower bulk density (compared to traditional masonry materials)—is very beneficial in such applications. A current trend in AAC development is the utilization of secondary raw materials in high-performance AAC, characterized by higher bulk density and compressive strength than regular AAC. The increase in bulk density is achieved by increasing the content of quartz sand in the mixing water. In this study, part of the siliceous component was replaced by ladle slag, foundry sand, furnace lining, and chamotte block powder. These materials are generated as by-products in metallurgy. The substitution rates were 10% and 30%. The samples were autoclaved in a laboratory autoclave for 8 h of isothermal duration at 190 °C with a saturated water vapor pressure of 1.4 MPa. The physical–mechanical parameters were determined, and the microstructure was described by XRD and SEM analyses. The results were compared with traditional AAC, with silica sand being used as the siliceous component. The measurement results show that sand substitution by the secondary raw material is possible, and it does not have a significant impact on the properties of AAC, and in a proper dosage, it can be beneficial for AAC production.

Enhanced Sinterability and Mechanical Strength of Beta-type Tricalcium Phosphates Ceramics through Reaction Sintering with Hydroxyapatite

Beta-tricalcium phosphate (β-TCP) ceramics were fabricated via reaction sintering at 1100 °C, utilizing various phosphate salts and calcium compounds as raw materials. The sintering characteristics, reaction sintering behavior and mechanical properties of the resulting β-TCP ceramics were investigated. Reaction sintering with a Ca/P molar ratio of 1.50 consistently generated β-TCP. In addition, a notable variance in physical properties was observed contingent on the presence or absence of stoichiometric hydroxyapatite (HAp; Ca10(PO4)6(OH)2) in raw materials. Sintered bodies produced with HAp−β-Ca2P2O7 (β-CPP), HAp− CaHPO4·2H2O (DCPD) and HAp−(NH4)2H(PO4) all exhibited densification and enhanced mechanical strength, correlated with higher bulk densities. In contrast, conventional sintered bodies prepared from β-TCP and reaction sintered bodies prepared using β-CPP−Ca(OH)2 or β-CPP−CaCO3 were not as dense. Comprehensive assessments by thermogravimetry-differential thermal analysis, X-ray diffraction and scanning electron microscope together with the evaluation of shrinkage behavior were used to monitor the sintering of β-TCP with HAp. This process was found to involve thermal decomposition of HAp and crystal transitions leading to the formation and sintering of β-TCP with significant shrinkage. These findings underscore the efficacy of employing HAp as a raw material in reaction sintering. This technique allows the formation of sintered β-TCP bodies exhibiting exceptional sintering characteristics, superior bulk density and high mechanical strength.

Preparation of tenofovir amibufenamide fumarate spherical particles to improve tableting performance and sticking propensity by designing a spherical crystallization process

Tenofovir amibufenamide fumarate (TMF) is the first oral drug developed in Asia for the treatment of adult patients with chronic viral hepatitis B, however, further applications are limited by poor tableting performance and high sticking propensity. In this work, the spherulitic growth process of TMF has been designed and explored with the help of molecular dynamics simulation and process analysis technologies (ATR-FTIR, FBRM and EasyViewer). The spherical particles with high bulk density, good flowability and uniform particle size distribution are prepared by a simple quenching process. More importantly, experimental results show that spherical particles have higher average tensile strength (100.8% increase), higher plastic deformability and lower amount of punch sticking (87.4% decrease in 30 tablets) compared to the commercial powder products. These contributions not only shed light on the design principle of drug spherulitic growth processes, but also provide guidance for the manufacture of high-quality tablet products.

Preparation of high-purity magnesia spinel refractory raw materials with spinel-wrapped periclase structures using bischofite from salt lake

A large amount of bischofite is produced in the process of potassium extraction from salt lake, which seriously affects the ionic balance of brine system. In this study, a high-purity magnesia spinel refractory raw material with a spinel-wrapped periclase structure was directly prepared using bischofite by a precipitation-sintering approach. A coupling process of one-time crude magnesium chloride solution recrystallization and three-time precipitates washing was employed to remove crucial impurities (sodium, potassium, boron, etc.) and prepare the magnesium hydroxide precipitates with a high purity of 99.37 %. The lightly calcined magnesia gained from the high-purity magnesium hydroxide precipitates and white corundum were then employed for preparing the refractory raw materials. The effects of particle size and dosage of white corundum on the phase distribution, microstructure, and physical properties of the materials were thoroughly studied. The results illustrated that the prepared refractory raw materials were mainly composed of periclase and spinel phases, showing a distinct spinel-wrapped periclase structure that could enhance the physical properties. Therefore, the prepared refractory raw materials showed a high bulk density of 3.46 g·cm−3, a low apparent porosity of 2.46 %, and a linear shrinkage rate of 12.33 %, under the optimum conditions of white corundum particle size of 3.00 μm and alumina/magnesia mass ratio of 3:10.

Preparation of low-sensitivity explosive composite spheres via oil-in-oil emulsion

In order to reduce mechanical sensitivity and improve process performance of TKX-50, spherical TKX-50/TATB composite was prepared via the oil-in-oil emulsion method with TKX-50 (Dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate) and TATB (1,3,5-triamino-2,4,6-trinitrobenzene) as raw materials. Based on the experimental results, the ideal circumstances for the emulsion to stabilize were obtained. The SEM results of spherical TKX-50/TATB composite exhibited an excellent spherical structure and size distribution. Furthermore, the SEM, XRD, and FT-IR results of spherical TKX-50/TATB composite demonstrated composite effect of the two basic materials was good. Compared to raw TKX-50 and TATB, the activation energies of spherical TKX-50/TATB composite decreased by 32.75 kJ mol−1 and 33.61 kJ mol−1, respectively. The TKX-50/TATB physical mixture was compared with spherical TKX-50/TATB composite, which had a higher bulk density and flowability. The impact sensitivity H50 of spherical TKX-50/TATB composite was 66.1 cm, which was 50.6 cm higher than that of raw TKX-50, and its friction sensitivity was reduced from 32 % to 24 % compared with that of raw TKX-50.

In situ boro-mullite phase formation in Glass–Ceramic glazes: Anatase–rutile phase transformations and microstructure properties

‘‘Boro-mullite’’ is the name for mullites produced through the synthesis of boron-rich material and playing a critical role in producing high-performance materials. Also, the stability of the anatase phase in the glaze and against temperature has been addressed and improved by many studies. In situ boro-mullite crystals generated using various glass-ceramic glaze compositions that contain TiO2 and their impact on the transformation of anatase into a rutile phase were examined in this study. Additionally, the samples' water absorption, bulk density, apparent porosity and shrinkage, Vickers hardness, and optical properties were evaluated at various Al2O3 and B2O3 amounts at 700 °C, 800 °C, 900 °C, 1000 °C and 1100 °C. X-ray diffraction analysis revealed that as the temperature and Al2O3 ratio rose, it triggered the boro-mullite phase formation. On the other hand, increasing the Al2O3 ratio led to a rise in the samples' sintering temperature and delayed the anatase to rutile phase transformation. Furthermore, the presence of corundum crystals retarded the anatase crystal size growth during the remodelling process of the conversion of anatase to rutile. While the increase in the B2O3 ratio sharpened the peaks of albite crystals, the formation of rutile crystals accelerated with the increase in temperature and caused inhibition of albite formation. The albite phase's presence facilitated the creation of the liquid phase and achieved the 0.010 % water absorption and 0 % apparent porosity values as well the highest bulk density and microhardness with 2.476 g/cm3 and 550 H V. The yellowness (+b∗) values were found to be the highest at 1100 °C where the rutile crystals reached their maximum size. The anatase-rutile conversion is postponed and the increase in the yellowness value is prevented by the glaze's formation of boro-mullite. FESEM-EDS analysis showed that the temperature was the driving force in the transformation of acicular boro-mullite crystal into highly acicular prismatic needle crystal and spherical anatase crystals into the rod shape rutile.

Nature‐based shoreline protection in newly formed tidal marshes is controlled by tidal inundation and sedimentation rate

AbstractMany tidal marshes have been lost by past land use changes, but are nowadays increasingly restored and created to provide valuable ecosystem services such as nature‐based flood and erosion protection along estuarine shorelines. To be functional for flood and shoreline erosion protection, restored and created tidal marshes should develop erosion resistant sediment beds. Here, we investigated which factors drive the spatial variations in sediment strength and erosion resistance in a developing tidal marsh restoration site. Our results show that decreasing tidal inundation frequency, decreasing sedimentation rate, and better drainage led to stronger consolidation in deeper sediment layers. This consolidation resulted in greater sediment strength, quantified here by shear strength and penetration resistance. Generally, sediment strength was greater when sediment had higher bulk density, while a higher water and fine fraction (= clay and silt) content decreased sediment strength. Overall, all measurement locations were relatively erosion resistant, likely caused by the dense root network and cohesive sediment. To restore or create resilient tidal marshes for nature‐based flood and shoreline erosion protection, we should thus aim for sites with relatively low tidal inundation frequency, moderate sedimentation rates, and cohesive sediment mixtures of clay, silt, and sand, which are well drained and have potential for vegetation establishment. These conditions have a high likelihood of resulting in restored or created tidal marshes that contribute to nature‐based flood and shoreline erosion protection.

Spatial variability in blue carbon storage and sequestration of seagrass meadows in southern China

Although seagrass meadows are intense carbon sinks, information on the regional variability in seagrass blue carbon stocks and carbon sequestration remains limited. We estimated the organic carbon (Corg) stocks and carbon accumulation rates (CAR) of seven seagrass meadows along the subtropical coast of China's Zhanjiang City and analyzed the driving factors of variability in sediment Corg stocks in three seagrass meadows. Results showed that most Corg (99.83 %) was stored in the sediments, and the contribution of living biomass was minor. The average Corg stocks of living biomass and sediments across all sites were 0.04 ± 0.01 and 42.03 ± 25.07 Mg C ha−1, respectively, which were significantly lower than the world average (2.52 ± 0.48 and 194.2 Mg C ha−1). The sediment Corg stocks of the upper 1 m ranged from 24.26 to 157.12 Mg C ha−1 with substantial variability among sites: Liusha Bay (64.93 ± 22.31 Mg C ha−1) > Donghai Island (33.8 ± 10.65 Mg C ha−1) > Dongshen Ferry (27.35 ± 4.15 Mg C ha−1). The average sediment CAR was 53.47 g C m−2 yr−1, and the total CAR of 864.18 ha seagrass meadows was 260.76 ± 4.86 Mg C yr−1 in these studied sites. Physicochemical factors, such as high moisture content, salinity, CaCO3 content, and low dry bulk density, jointly inhibited the mineralization rate of Corg in sediments. Our study provides data from understudied regions to a growing dataset on seagrass carbon stocks and sequestration rates and highlights the significance of local and regional differences in seagrass blue carbon storage to accurately assess the climate change mitigation potential of seagrass ecosystems.

Nutritional, Phytochemical, Functional and Antioxidant Properties of Acha, Chia and Soycake Flour Blends

Functional flour blends are been developed with nutritional and health promoting benefits to fit in to the third agenda of Sustainable Development Goal (SDG) 2030. A blend of fermented acha (FAF), defatted chia (DCF), and defatted soycake flours (DSF flour were blended to harness the proficient potential of the blends. Response surface methodology (RSM) was used to generate fourteen runs using the the protein and the crude fibre of the flour blends. The three blends that the protein ranges from 15-20% and fibre from 3-5% were selected and the composite flours were analyzed for proximate composition, minerals, phytochemical composition, functional properties, and antioxidant properties. Results indicated that protein content increased with higher DSF proportions ranging from 15.37% in ACSF13 (80% of fermented acha, 10% of defatted chia seed, 10% soycake) to 19.51% in ACSF9 (45% of Fermented acha, 10% of defatted chia seed, 45% soycake). Energy content also rose from 335.4 kcal to 391.4 kcal in ACSF13 to ACSF1 (57% of fermented acha, 22% of defatted chia seed, 21% Soycake). ACSF1 is the blend with the highest fibre (5.06%) and ACSF9 possess the highest ash content of (4.13%). The blends were rich in potassium, calcium, zinc, iron and magnesium with phytochemical, phytate- mineral ratio and oxalate mineral ratio within recommended levels. Sample ACSF1 had the highest bulk density while ACSF9 possess both the highest swelling capacity and water absorption. The total phenolic and flavonoid content of the flour blends ranged from 273.55 to 149mg GAE/g and 66.71 to 31.60mgQE/g with sample ACSF13 having the highest phenolic content (273.55GAEmg/g) and flavonoid content of 66.71mgQE/g. The increase in the Soycake flour is an indications to improvement on the nutritional values of the flour blends.

Predicting the soil bulk density using a new spectral PTF based on intact samples

Sample collection and measurement of soil bulk density (BD) are often labor-intensive and expensive in large regions. Conversely, soil spectra are easy to measure and facilitate BD prediction. However, the literature suggests that the damage to the physical structure of soil during scanning spectra on the ground and/or sieved samples might hinder the capacity of spectral technology to accurately predict BD. In addition, because some soil properties that have high correlations with BD, such as the soil organic matter (SOM), are routinely measured and available in most soil databases, coupling them with soil spectra may improve BD prediction compared to using soil properties or spectra. Therefore, in this study, we propose a novel spectral pedo-transfer function (spectral PTF) that couples the measured visible and near-infrared spectra of soils on intact samples and other soil properties to accurately predict the BD (BD = f (soil spectra, soil properties)), which is different from the traditional PTF that uses only soil properties (BD = f (soil properties)) or spectra alone (BD = f (soil spectra)). In this study, we collected topsoil (0–20 cm) and subsoil (20–40 cm) samples from 586 sites in Northeast China, covering a large area of 1.09 million km2 characterized by black soils with high SOM contents. Five routinely measured soil properties were selected: SOM, moisture content (MC), Sand, Silt, and Clay, and various spectral PTFs with one, two, and three soil properties were calibrated using the partial least square regression. The cross-validation results show that the traditional PTF can only predict BD for subsoil with an R2 of 0.51 and an RMSE of 0.11 g·cm−3 when using SOM + MC + Silt or SOM + MC. Compared to subsoil, topsoil and all layers (topsoil + subsoil) had a lower BD prediction accuracy, and a saturation effect was observed for BD values above 1.5 g·cm−3. Unexpectedly, the soil spectra did not provide a higher BD prediction accuracy than traditional PTFs, although the spectra were measured on intact samples. However, adding soil properties to the spectral PTF improved the prediction accuracy and saturation effect for high BD values. The optimal spectral PTF with a single soil property (MC) showed an acceptable BD prediction performance with R2≥0.49, RPD>1.4, and RPIQ>1.7 regardless of whether the sample was topsoil, subsoil, or all layers. Furthermore, the spectral PTF with two or three soil properties yielded a slightly better prediction performance and a more stable prediction among different combinations of soil properties. These results indicate that soil properties and spectra are irreplaceable for BD prediction. Our study demonstrates the potential of spectral PTFs for the accurate prediction of BD and offers insights into the prediction of other soil properties using soil spectra.

Cold-sintered laterite-based geopolymers: Densification, microstructure and micromechanics

The consolidation of natural iron-rich aluminosilicates is enhanced using geopolymerisation, external pressure, and temperature in a ultra-low energy sintering context. Optimized formulations of laterite and Rice Husk Ash (RHA) are used to investigate the effects of the external pressure and temperature on the porosity, phases composition development, micromechanics and microstructure. FT-IR spectroscopy, scanning electron microscopy (SEM 0, Mercury Intrusion Porosimetry (MIP), Transmission Electronic Microscopy (TEM), and the Archimedes Porosimetry method were used to characterize the cold sintered products of geopolymerization of the iron-rich aluminosilicate binders and composites. Results showed that ultra-low energy sintering process allows the reduction of ∼ 99 % of capillary porosity thank to the physico-chemical bonding and the formation of enhanced nanosized ferrisilicates. The indentation modulus > 50 GPa, the hardness modulus of 3,18 GPa and the fracture toughness > 1 MPa m0.5 are in agreement with the compact microstructure, high bulk density (> 2.00 g.cm−3), and low water Absorption. The interlocking of globular units of H-N-(A, Fe)-S with nanosized ferrisilicates leads to high performance ceramics that cannot be achieved with conventional sintering process. Therefore, the cold sintering process demonstrated here is promising for the manufacturing of sustainable matrices using natural iron-rich aluminosilicates.