Size Distribution Analysis Research Articles

Triaxial Test of Coarse-Grained Soils Reinforced with One Layer of Geogrid

Geosynthetics play a pivotal role in modern infrastructure projects, with geogrids serving as a common choice for enhancing bearing capacity and reducing soil settlement in road construction. This study investigates the influence of density and uniformity coefficients on geogrid-reinforced sandy and gravelly soils through a series of consolidated drained triaxial tests. The research covers six distinct soil types from Lithuania, each characterized by particle size distribution analysis and classified using various standards. A polyester biaxial geogrid is employed, and test specimens are prepared with and without geogrid reinforcement. Triaxial compression tests are performed at different cell pressures, mirroring real-world conditions in road construction. The results highlight the critical role of cell pressure in the reinforcement effect, with higher pressures reducing the geogrid’s influence. The study also emphasizes the importance of soil type, as gravel soils consistently exhibit higher deviatoric stress than sandy soils. Notably, the geogrid enhances cohesion but reduces the angle of internal friction in most cases. Overall, this research provides valuable insights into the intricate interplay between soil properties, geogrid reinforcement, and cell pressure, shedding light on the mechanical behavior of geosynthetic-reinforced soils in road construction applications.

Analysis of friction and wear performance of eco-friendly basalt filler reinforced polylactic acid composite using the Taguchi approach

The main goal of this research is to utilize sustainable and eco-friendly basalt materials for the fabrication of bio-based thermoplastic composites. This will help to keep up with ecologically balanced factors. There have been several studies on natural fiber reinforced with different polymer matrices during the past 10 years. As a result, the academics and experts expressed concern about the environmental imbalance. By keeping these points, an attempt was made to fabricate basalt fillers reinforced polylactic acid composites with the maximum weight ratio (30 wt %), and the tribological study is conducted for the fabricated composites. In this study, the Taguchi and analysis of variance (ANOVA) approaches have been used to analyze the coefficient of friction (COF) and specific wear rate (SWR) of polylactic acid composite reinforced with constant 30 wt% basalt fillers. The morphology, particle size, and elemental composition of the basalt fillers are examined using scanning electron microscopy, a particle size distribution analyzer, and energy-dispersive X-ray analysis, respectively. The tribology tests are conducted with Pin-on-Disk Tribometer following the ASTM G99 standard, following the L18 orthogonal array design, which was developed using the statistical program MINITAB-19. The selected parameters for the analysis are basalt (wt %), load (N), speed (rpm), and distance (m) under dry conditions. For PLA samples, the optimum parameters in response to COF is found to be 0 wt% basalt, 3 N load, 100 rpm speed, and 100 m distance; for the SWR output, the optimum parameters are 30 wt% basalt, 6 N load, 100 rpm speed, and 150 m distance. The consistent observation is that adding basalt fillers has not significantly reduced COF but has contributed more to SWR reduction with PLA composite. The best COF value for PLA samples is obtained with low sliding distance. The typical observation across all COF graphs is that the COF value first seems to be lower due to a smoothened polymer surface, rises throughout an experiment, and then stabilizes with very little variance. Regardless of the processing parameters, the depth of wear steadily increases with increasing load as observed in 2D depth profiles. The neat PLA polymer morphology that gives the illusion of deep grooves and many tracks dispersed over a single worn surface shows how the maximum parameter influence is more obvious on the surface of the sample. Overall, the results suggest that thermoplastic composites are feasible for the manufacturing of paper mill rollers.

Development of a PAT platform for the prediction of granule tableting properties

In this work, the feasibility of implementing a process analytical technology (PAT) platform consisting of Near Infrared Spectroscopy (NIR) and particle size distribution (PSD) analysis was evaluated for the prediction of granule downstream processability. A Design of Experiments-based calibration set was prepared using a fluid bed melt granulation process by varying the binder content, granulation time, and granulation temperature. The granule samples were characterized using PAT tools and a compaction simulator in the 100-500kg load range. Comparing the systematic variability in NIR and PSD data, their complementarity was demonstrated by identifying joint and unique sources of variation. These particularities of the data explained some differences in the performance of individual models. Regarding the fusion of data sources, the input data structure for partial least squares (PLS) based models did not significantly impact the predictive performance, as the root mean squared error of prediction (RMSEP) values were similar. Comparing PLS and artificial neural network (ANN) models, it was observed that the ANNs systematically provided superior model performance. For example, the best tensile strength, ejection stress, and detachment stress prediction with ANN resulted in an RMSEP of 0.119, 0.256, and 0.293 as opposed to the 0.180, 0.395, and 0.430 RMSEPs of the PLS models, respectively. Finally, the robustness of the developed models was assessed.

Synthesis of carbon quantum dot synthesized using spent coffee ground as a biomass exhibiting visible-light-driven antimicrobial activity against foodborne pathogens

The aim of this study was to synthesize carbon quantum dot (CQD) exhibiting visible-light-driven (VLD) antimicrobial activity using spent coffee ground (SCG) as biomass. SCG was used to synthesize CQD through microwave treatment. It was confirmed that typical CQD was synthesized well based on morphology (high resolution transmission electron microscopy), size distribution (dynamic light scattering), and chemical structure (X-ray photoelectron spectroscopy) analyses. VLD antimicrobial activities of CQD synthesized from SCG against Staphylococcus aureus and Escherichia coli O157:H7 were found to be increased as pH decreased. Photodynamic properties of CQDs such as fluorescence quantum yield (FLQY), band gap energy (Eg), and fluorescence lifetime as photodynamic properties of CQDs related to VLD antimicrobial activity did not show any significant changes according to pH change. However, as pH decreased, negative zeta potential (mV) values of CQD and pathogenic bacteria gradually decreased. As a result, it was confirmed that CQD uptake into pathogens was gradually increased due to a decrease in repulsive force between them. In addition, it was found that as pH decreased, activities of enzymes (superoxide dismutase and catalase) known to scavenge reactive oxygen species (ROS) in cells decreased. In the presence of CQD, when visible light was applied, the amount of ROS generated inside cells increased as pH decreased. Based on these results, CQD synthesized from SCG was combined with organic acid (malic acid) for practical application in fresh produce (apple surface) washing. It was confirmed that such combination had an excellent control effect against pathogenic bacteria, suggesting that this strategy could be effectively utilized in the food industry.

Characterization of Recycled Aggregates in Existing Pavement Base Layers

ABSTRACT The use of recycled pavement materials in transportation infrastructure projects has contributed positively to maintaining a sustainable flow of construction materials and sources. Geotechnical properties of recycled pavement materials play a major role in the suitability of such materials for use in civil infrastructure. This study aimed at evaluating the properties of recycled concrete aggregates (RCA) and reclaimed asphalt pavements (RAP) used as base layer materials in existing hot mix asphalt pavements (with service life of more than 8 years) and comparing them with virgin crushed aggregate (CA) base materials of similar service life. Coring of flexible pavement surface layers at 18 pavement sites was performed to expose the base course layer materials for sampling and testing. Then, the dynamic cone penetrometer (DCP) test was conducted in which the cone penetrated through base layers to the subgrade when possible. Thereafter, base materials were retrieved from the pavement sites for laboratory testing and evaluation. Laboratory tests consisted of particle size analysis, specific gravity and absorption, and Micro-Deval abrasion. Analysis of the particle size distribution showed the presence of high sand size fractions in both RCA and RAP base materials compared with virgin CA base materials. This indicated the recycled materials were crushed/milled to smaller size fractions or degraded under freeze-thaw cycles and traffic loads during the pavement’s service life, or both. The RCA base materials exhibited the highest absorption and mass loss in the Micro-Deval test. The DCP test results were used to predict California bearing ratio (CBR) and resilient modulus (Mr) of base materials. The predicted CBR and resilient modulus of the recycled base materials showed that RCA, RAP, and CA all had comparable strength and modulus values that were high. The investigated recycled RCA and RAP aggregates possessed properties that are comparable with the properties of the virgin CA.

Outstanding effect of cost-saving heavy nano-ferrites on the physico-mechanical properties, morphology, and gamma radiation shielding of hardened cement pastes

The purpose of this study is to synthesize heavy nano-ferrites (e.g. nano-CaFe2O4 and nano-CuFe2O4) using facile and economical sol–gel method to investigate their effect on the physico-mechanical, morphological, and gamma radiation shielding of hardened cement pastes. After the synthesis process, the nano-ferrites were characterized using transmission electron microscopy (TEM), scanning electron microscopy/energy dispersive X-ray (SEM/EDX), X-ray diffraction (XRD) and particle size distribution analyses and then admixed to ordinary Portland cement (OPC) with different doses (e.g., 0, 0.25, 0.5, 1, and 2 mass%). The physico-mechanical characteristics of the cement pastes containing different ratios of heavy nano-materials were investigated at various hydration times. SEM/EDX and FTIR techniques were employed in addition to TGA/DTG to describe the microstructure and phase composition of the different hardened pastes. Gamma linear attenuation coefficients for Cs137 (662 keV) and Co60 (1173 and 1332 keV), as well as the most essential gamma transmission characteristics (half-value layer, HVL; tenth-value layer, TVL; and mean free path, MFP), were determined for selected pastes. The results revealed that the EDX spectrum of nano-CaFe2O4 clarifies that the Fe, Ca, and O elements are clearly observed at their corresponding keV values. Moreover, EDX spectrum of nano-CuFe2O4 properly reveals the presence of Cu, Fe, and O elements. These results confirm that the obtained product was of high purity. In addition, TEM photos indicate that the particle size of nano-CaFe2O4 is in the range of 7–22 nm, while the particle size range of nano-CuFe2O4 is 8–27 nm. It was found that the cement pastes containing 1% nano-CaFe2O4 and 1% nano-CuFe2O4 were the pastes that improved the physico-mechanical properties and high gamma ray shielding properties compared to the other prepared pastes. These nano-materials have high efficiency and economic feasibility.

Sensory Evaluation, Physico-Chemical Properties, and Aromatic Profile of Pasteurised Orange Juice with Resistant Maltodextrin.

The beneficial health effects of prebiotics have been demonstrated in numerous research papers. However, their incorporation into daily food remains unfamiliar to consumers. This work evaluates the effects of the addition of resistant maltodextrin (RMD) on the sensory attributes of pasteurised orange juice, together with the physico-chemical properties and the aromatic profile. RMD addition increased the sweetness and decreased the acidity and bitterness, resulting in a higher overall panellists' rating of orange juice. It also proportionally increased °Brix together with density and decreased acidity. Colour changes were registered with higher RMD concentrations. Orange pulp presence affected the volume particle size distribution analysis, while RMD addition did not have any effect. The aroma volatile compounds were also analysed. Pulp-added samples showed a higher quantity of alcohol and aldehydes, whereas pulp-free samples registered higher terpene and terpenoid values. Ketones and acids were also quantified. RMD had a moderate impact on volatile compound quantifications, with the orange pulp presence playing a much more decisive role. A correspondence analysis was also performed to relate instrumental and sensory determinations for all samples. This work proves that the addition of RMD to orange juice is technologically feasible while also achieving a good response at the sensory level.

Unleashing the dye adsorption potential of polyaminoimide homopolymer: DFT, statistical physics, site energy and pore size distribution analyses

The efficient removal of Congo Red (CR) dye from aqueous solutions is an important issue in environmental protection. This study presents the synthesis and optimization of a polyaminoimide homopolymer (PHP) adsorbent for the removal of CR dye. To optimize the synthesis of PHP, ten different compositions of maleic anhydride and ethylene diamine were tested, with PHP3 demonstrating the highest efficacy. The adsorption process was further enhanced by optimizing pH, temperature, adsorbent dose, and initial dye concentration. Isotherm and kinetic studies revealed that the Langmuir-Freundlich model and the pseudo-second-order kinetics best described the adsorption process. Moreover, PHP3 demonstrated significantly greater selectivity for CR compared to Synozol yellow, and Sulfasalazine. Advanced statistical models were used to analyze the adsorption data, and the single-layer model with single energy (M1) being the most suitable, suggesting that CR molecules were adsorbed onto PHP3 in a perpendicular position through a multimolecular process, the adsorption process is physical, endothermic, spontaneous and specific surface area of PHP3 increased from 54.31 to 115.74 m2 g−1 as temperature rose from 288 to 318 K. Site energy distribution and pore size distribution studies showed that PHP3 has a heterogeneous energy distribution on its surface, and that the adsorption of CR dye primarily takes place in the macropores of PHP3. Density Functional Theory analysis indicated that PHP3 has electron-rich amine groups that can interact with electron-deficient sulfonate groups in CR, while electron-poor amide groups in the polymer can interact with the electron-rich azo group in Congo Red. It also shows that the presence of NaF, Na2SO4, and KCl salts did not significantly affect the CR adsorption, indicating the potential affinity/selectivity of PHP3 towards CR dye. The findings suggest that PHP3 could be an effective and promising adsorbent for industrial applications in wastewater treatment.

Enhanced harvest performance predictability through advanced multivariate data analysis of mammalian cell culture particle size distribution.

The industry's pursuit for higher antibody production has led to increased cell density cultures that impact the performance of subsequent product recovery steps. This increase in cell concentration has highlighted the critical role of solids concentration in centrifugation yield, while recent product degradation cases have shed light on the impact of cell lysis on product quality. Current methods for measuring solids concentration and cell lysis are not suited for early-stage high-throughput experimentation, which means that these cell culture outputs are not well characterized in early process development. This article describes a novel approach that leveraged the data from a widely-used automated cell counter (Vi-CELL™ XR) to accurately predict solids concentration and a common cell lysis indicator represented as lactate dehydrogenase (LDH) release. For this purpose, partial least squares (PLS) models were derived with k-fold cross-validation from the particle size distribution data generated by the cell counter. The PLS models showed good predictive potential for both LDH release and solids concentration. This novel approach reduced the time required for evaluating the solids concentration and LDH for a typical high-throughput cell culture system (with 48 bioreactors in parallel) from around 7 h down to a few minutes.

Gold nanoparticle conjugation enhances berberine's antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA)

Nanoparticle (NP) conjugation with various biomolecules is one of the most promising approaches for targeting Methicillin-resistant Staphylococcus aureus (MRSA). In this study, berberine (BER) was conjugated with gold nanoparticles (AuNPs) to enhance its antibacterial activity against MRSA. Chemically synthesized AuNPs were characterized by UV–vis spectroscopy, size distribution and Field Emission-Scanning Electron Microscope (FE-SEM) analysis. Berberine was conjugated with AuNPs and the conjugants were characterized using UV–vis spectroscopy and Fourier Transform Infrared (FTIR). The cytotoxicity of free and conjugated BER was also investigated. Comparative studies were conducted based on the Minimum Inhibitory Concentration (MIC) and anti-biofilm activities of conjugants and free BER against MRSA isolates. To verify cell membrane disruption and intracellular imbalance following treatment exposure, reactive oxygen species (ROS) and live-dead staining experiments were performed. In vivo antibacterial efficacy of treated groups was also assessed in a BALB/c mouse-infected skin model. DLS measurement, FE-SEM, and UV–vis spectroscopy confirmed the synthesis of AuNPs with a narrow size distribution of 49.38 nm and a zeta potential of −31.9 mV. The results from UV–vis spectroscopy and FTIR provided support for the functionalization of AuNPs by BER functional groups. The In vitro antibacterial results demonstrated that the conjugated BER exhibited a lower MIC value against MRSA (109.5 μg/ml) compared to free BER (165 μg/ml). Free and conjugated BER, at their MIC concentrations, demonstrated anti-biofilm activity, resulting in biofilm eradication of 13.9 and 22.33 %, respectively. The highest level of ROS production (93 %) was associated with the conjugated BER at a concentration of 27.37 μg/ml. This finding indicates a disruption in cell membrane integrity and a reduction in bacterial viability, as demonstrated by ROS and live/dead staining assays. The cytotoxicity study on the mouse L929 fibroblast cell line revealed approximately 100 % cell viability when exposed to free or conjugated BER at their MIC concentration. This result indicates the biosafety of both of the compounds. The in vivo study in the infected skin model groups treated with conjugated and free BER revealed MRSA survival rate of 2.7 % and 26 %, respectively. These findings suggest that conjugated BER could be an effective nanoformulation candidate with a potential role in managing MRSA associated infections.

Analysis of particle size distribution and electro-kinetics of submicron particles in shear-thinning liquids

Analysis of particle size distribution and electro-kinetics of submicron particles in shear-thinning liquids

A novel Chitosan-Barbituric acid hydrogel supersorbent for sequestration of chromium and cyanide ions: Equilibrium studies and optimization through RSM

The objective of this study is to transform chitosan biopolymer by crosslinking with barbituric acid into an amine-rich product that could be applied as a water treatment agent. Chitosan-barbituric acid (CBA) was synthesized by lyophilization process and characterized using FT-IR, XRD, TGA-DTA, SEM-EDX, BET surface area and BJH pore size distribution analysis. The pHpzc was found to be 7.7 indicating applicability towards both cations and anion adsorption. The CBA was used for seizure of CrVI and CN– from aqueous solutions in batch adsorption as well as fixed bed column experiments. Response surface methodology (RSM) was used as a statistical tool to optimize the functioning parameters resulting in more than 90 % removal of these ions. As shown by isotherm and kinetics data, Langmuir isotherm and pseudo second order kinetics exhibited a good fit for the adsorption process. The maximum adsorption capacities of CBA towards CrVI and CN– evaluated using Langmuir isotherm fitment were 534.75 mg g−1 and 251.66 mg g−1 at pH 4.0 and 6.0 respectively. Thermodynamic studies indicated spontaneous and enthalpy driven course with large negative enthalpy changes of −56.39 and −31.81 kJ mol−1 respectively. Fixed bed column studies showed that the material could be used for larger sample volume treatment even at 200 mg/L CrVI and 100 mg/L CN−1 concentration. Regeneration studies of adsorbent was conducted over five adsorption–desorption cycles with removal efficiency more than 50 %indicating reusability of the adsorbent. Analysis of adsorbent sustainability revealed that the synthesis was eco-friendly as indicated by low value of E-factor of 0.32.

Deinterpenetration of IRMOF-9.

One of the iconic characteristics of metal-organic frameworks (MOFs) is the possesssion of guest-accessible pores. Increasing pore size has a direct and often beneficial impact on a MOF's adsorption and separation properties. However, as pore size increases, the resulting void spaces are often filled by interpenetrated frameworks, where one or more networks crystallize within the pore system of another identical network, reducing the MOF's free volume and pore size. Furthermore, due to the thermodynamic favorability of interpenetration during solvothermal synthesis, techniques to synthetically differentiate interpenetrated from non-interpenetrated MOFs are paramount. Herein we report the synthesis of deinterpenetrated IRMOF-9 via halide mediated deinterpenetrative conversion of Zn4O-derived IRMOF-9. IRMOF-9, when treated with ethylammonium bromide, is quasi-selectively etched, revealing the non-interpenetrated analogue, IRMOF-10 (deinterpenetrated IRMOF-9), which can be isolated prior to complete dissolution by the bromide solution. Dye adsorption, surface area and pore size distribution analysis, powder X-ray diffraction, and elemental analysis are consistent with successful deinterpenetration.

Generation of Simulated "Natural" Nanoplastics from Polypropylene Food Packaging as the Experimental Standard.

Current toxicology research on nanoplastics (NPs) generally uses commercial spherical NPs. However, the physicochemical characteristics of commercial NPs are significantly different from those of NPs formed under natural conditions, possibly affecting the validity of the results. In analytical chemistry, a reference sample is selected such that its physicochemical properties are as similar as possible to the target. Therefore, a simulated "natural" NP synthesized in the laboratory that closely resembles naturally derived NPs would be used as an authentic standard. Here, we established the assay of scanning electron microscope (SEM)-particle size distribution analyzer (PSDA)-surface-enhanced Raman scattering (SERS) to detect NPs and prepared simulated "natural" NPs from polypropylene food packaging material using a method that mimics natural conditions. Nanofiltration was used to isolate three sets of simulated NPs with particle sizes ranging from 50-100 nm, 100-200 nm, and 200-400 nm. These simulated "natural" NPs were more similar to naturally occurring counterparts when compared with commercial NPs. These new standard NPs, which should be scalable for large-scale use, will improve the accuracy, reliability, and translatability of toxicological studies of NPs.

Magnesium oxychloride cement with hydrophobic pore network for utilizing as oil well cement

Magnesium oxychloride cement (MOC) possesses some excellent characteristics, which can be used as oil well cement, to deal with the complex environmental conditions in oil and gas wells. However, the water resistance property of MOC is poor. In this study, a new type of magnesium oxychloride cement (MOC) with improved water resistance was developed by modifying the pore structure of pure MOC using hydrophobic admixtures. To assess the performance of the new MOC, a range of tests were performed, including compressive strength, softening coefficient, capillary water absorption, pore size distribution, mineral composition and microstructure analysis. The results showed that the pore size distribution of the MOC was altered from a large pore-dominant structure to a small pore-dominant one. The hydrophobic admixture and the gel substance formed on the strength-providing phases prevented them from water erosion, resulting in enhanced strength and water resistance. This new type of MOC has the potential to be used in challenging environments, such as oil and gas wells and underwater structures.

Cement mortar composites including 1-tetradecanol@PMMA Pickering emulsion particles for thermal energy management of buildings

In this study, a poly(methyl methacrylate) (PMMA) shell 1-tetradecanol core microencapsulated phase change material (MPCM) was produced using the Pickering emulsion technique. Characterization tests of the produced MPCMs were performed using Fourier transform infrared (FT-IR) spectroscopy, particle size distribution (PSD) analysis, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) techniques. The latent heat, melting temperature and encapsulation rate of MPCM were determined and they were found as 108.4 J/g, 33 °C, and 46.7 % for heating period, respectively. The effect of 1-tetradecanol@PMMA MPCM on the physical, mechanical, and thermal performance properties of cementitious mortars was also investigated in the study. For this reasons 1-tetradecanol@PMMA MPCMs are included in mortar mixes at 5 %, 7.5 %, and 10 % by weight of cement. As the MPCM ratio increased, the water absorption rate and porosity increased, while the workability, unit weight of the mortar, ultrasonic pulse velocity, flexural strength and compressive strength parameters decreased. The compressive strength of the mortar containing 10 % MPCM on the 28th day was measured as 34.74 MPa. The highest thermal storage capacity was found in mortars containing 10 % MPCM. When the thermal performance of the reference and 10 % MPCM-containing mortars were compared, the indoor temperature differences at the end of the heating and cooling periods were measured as 4.7 °C and 3.9 °C, respectively. The results showed that MPCM produced by the Pickering emulsion technique has the potential to increase thermal comfort in buildings, reduce fuel consumption used for heating purposes and, accordingly, reduce carbon emissions.

Enhancing the Functional Properties of Tea Tree Oil: In Vitro Antimicrobial Activity and Microencapsulation Strategy.

In the context of addressing antimicrobial drug resistance in periocular infections, Tea Tree Oil (TTO) has emerged as a promising therapeutic option. This study aimed to assess the efficacy of TTO against bacterial strains isolated from ocular infections, with a particular focus on its ability to inhibit biofilm formation. Additionally, we designed and analyzed microcapsules containing TTO to overcome certain unfavorable physicochemical properties and enhance its inherent biological attributes. The quality of TTO was confirmed through rigorous analysis using GC-MS and UV-Vis techniques. Our agar diffusion assay demonstrated the effectiveness of Tea Tree Oil (TTO) against ocular bacterial strains, including Corynebacterium spp., coagulase-negative Staphylococcus spp., and Staphylococcus aureus, as well as a reference strain of Staphylococcus aureus (ATCC 25923). Notably, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for all tested microorganisms were found to be 0.2% and 0.4%, respectively, with the exception of Corynebacterium spp., which exhibited resistance to TTO. Furthermore, TTO exhibited a substantial reduction in biofilm biomass, ranging from 30% to 70%, as determined by the MTT method. Through the spray-drying technique, we successfully prepared two TTO-containing formulations with high encapsulation yields (80-85%), microencapsulation efficiency (90-95%), and embedding rates (approximately 40%). These formulations yielded microcapsules with diameters of 6-12 μm, as determined by laser scattering particle size distribution analysis, and exhibited regular, spherical morphologies under scanning electron microscopy. Importantly, UV-Vis analysis post-encapsulation confirmed the presence of TTO within the capsules, with preserved antioxidant and antimicrobial activities. In summary, our findings underscore the substantial therapeutic potential of TTO and its microcapsules for treating ocular infections.

Soil Water Retention and Pore Characteristics of Intact Loess Buried at Different Depths

Surface water infiltration is a primary factor responsible for engineering challenges and geological disasters on the Loess Plateau of China (LPC). Due to the extensive groundwater in this region, surface water must pass through thick unsaturated zones to recharge the groundwater reservoirs. Exploring the unsaturated hydraulic characteristics of loess, especially at varying depths, may significantly contribute to disaster prevention and mitigation and the pursuit of sustainable development in the Loess Plateau. The soil-water characteristic curve (SWCC), intricately linked to the soil’s pore structure, is a critical hydraulic parameter of loess. An exploration well with a depth of 30 m was excavated in the LPC to obtain intact specimens at depths of 5 m, 15 m, and 25 m. Basic physical property tests, SWCC measurements, and particle size distribution (PSD) analyses were conducted. Additionally, the relationship between PSD and SWCC is discussed in this paper. The findings highlight the influence of depth on the dominant pore size and distribution density, both of which decreased with increasing depth. The air occlusion value of the SWCC experienced an increase, and the slope of the SWCC in the transition zone exhibited consistency. These observations underscore the pivotal role played by pore structure in shaping the soil’s water-retention behavior. Furthermore, predictions based on PSD data demonstrated excellent accuracy in replicating the wetting SWCC of loess over a wide suction range (e.g., 10–104 kPa).

Brash ice macroporosity and piece size distribution in ship channels

Merchant vessels' performance on brash ice plays an important role in navigation in fast ice conditions in Northern Baltic ports. Among many parameters, the piece size distribution and macroporosity of the brash ice influence the accuracy of the model simulations of ship performance in brash ice. These properties also govern the brash ice accumulation and consolidation in ship channels. The current work presents analyses of macroporosity and piece size distribution from three full-scale brash ice channels investigated during winters 2020–21 and 2021–22. The results provide insights into brash ice macroporosity and piece size distribution. Smaller brash ice pieces exhibited higher porosity. On each measured cross-section, the average macroporosity ranged from 1.4% to 23%, with standard deviations of 3.8% and 16%, respectively. Porosity variations were observed in relation to equivalent brash ice thickness, the number of ship passages, and cumulative freezing air temperatures. Total porosity and the channel's brash ice porosity initially increased with breaking events and then stabilized at approximately 23% and 30%, respectively, after 9 passages. In contrast, side ridge porosity increased initially (up to 23%) and subsequently decreased. The initial total, brash ice and side ridge maximal porosities after the breaking event were estimated equal to 25%, 35% and 30%, respectively. The first two channels, which were navigated a total of 9 and 10 times, had an average degree of brash ice consolidation equal to 0.84 and 0.76, and an average degree of side ridge consolidation equal to 1.1 and 1.0, respectively. The third channel, characterized by frequent navigation, exhibited a consolidation degree of 0.82 for brash ice and 1.35 in the side ridges. The average vertical piece size across all cross-sections ranged from 0.28 m to 0.52 m with standard deviations of 0.16 m and 0.25 m. The average horizontal piece size ranged from 0.33 m to 0.4 m with standard deviations between 0.2 m and 0.34 m. The horizontal piece size distribution of brash ice was best described by the probability density function of a three-parameter lognormal distribution.

Effects of sugar beet pectin on the pasting, rheological, thermal, and microstructural properties of wheat starch

The effects of addition of sugar beet pectin (SBP) on the pasting, rheological, thermal, and microstructural properties of wheat starch (WS) were investigated. Results revealed that SBP addition significantly increased the peak viscosity, trough viscosity, breakdown value, final viscosity, and setback value of WS, whereas decreased the pasting temperature. SBP raised the swelling power (from 13.44 to 21.32 g/g) and endothermic enthalpy (ΔH, from 8.17 to 8.98 J/g), but decreased the transparency (from 9.70 % to 1.37 %). Regarding rheological properties, WS-SBP mixtures exhibited a pseudo-plastic behavior, and SBP enhanced the viscoelasticity, but decreased the deformability. Particle size distribution analysis confirmed that SBP promoted the swelling of WS granules. Fourier-transform infrared spectroscopy results suggested that the interactions between SBP and WS did not involve covalent bonding, and the formation of ordered structure was inhibited by SBP addition. Additionally, scanning electron microscopy observation found that the gel network of WS-SBP mixtures became more irregular, pore size gradually decreased, and the wall became thinner as the SBP concentration increased. These results indicated that SBP is a promising non-starch polysaccharide that can enhance the processing properties of WS.