Changes In Properties Research Articles

The change of physical properties of calcium carbonate nanomaterials cured soil in road substrates

The utilization of appropriate materials to enhance road subgrade’s physical characteristics is crucial for current transportation construction and maintenance. This study proposes a curing method that employs calcium carbonate nanomaterials to address the problem of soil displacement and settlement in roadway subgrades. A method was developed during the study to explore the optimal curing material ratio. Additionally, this study developed a method for testing and analyzing the mechanical properties of soils cured with nanomaterials, including measures of tensile stress, triaxial shear stress, and Moore’s damage envelope. The study demonstrated that the unconfined compressive strength of the soil treated with calcium carbonate nanomaterials was 0.40 MPa after 7 days of curing with a 6% doping of the curing agent. Increasing the doping to 18% resulted in a breaking load of the soil reaching 0.100 kN. Furthermore, the triaxial shear stress–strain curve of the soil exhibited a slope of 264.47 during the linear phase when the curing agent was dosed at 6%. The slope of the linear phase of the stress–strain curve for triaxial shear at 6% curing agent doping was found to be 264.47. The cured soil molar pack line exhibited an internal friction angle of 22.66 degrees at the same curing agent dosage. The displacement analysis of the replacement roadbed with cured soil revealed a maximum observed displacement of only 377 mm after filling the embankment using the study method. The experimental results provide support for the hypothesis of the study, which suggests that the application of calcium carbonate nanoparticles can significantly enhance the physical characteristics of road subgrade.

Oxidative stress and DNA alteration on the earthworm Eisenia fetida exposed to four commercial pesticides.

Modern agriculture is mainly based on the use of pesticides to protect crops but their efficiency is very low, in fact, most of them reach water or soil ecosystems causing pollution and health hazards to non-target organisms. Fungicide triazoles and strobilurins based are the most widely used and require a specific effort to investigate toxicological effects on non-target species. This study evaluates the toxic effects of four commercial fungicides Prosaro® (tebuconazole and prothioconazole), Amistar®Xtra (azoxystrobin and cyproconazole), Mirador® (azoxystrobin) and Icarus® (Tebuconazole) on Eisenia fetida using several biomarkers: lipid peroxidation (LPO), catalase activity (CAT), glutathione S-transferase (GST), total glutathione (GSHt), DNA fragmentation (comet assay) and lysozyme activity tested for the first time in E. fetida. The exposure to Mirador® and AmistarXtra® caused an imbalance of ROS species, leading to the inhibition of the immune system. AmistarXtra® and Prosaro®, composed of two active ingredients, induced significant DNA alteration, indicating genotoxic effects. This study broadened our knowledge of the effects of pesticide product formulations on earthworms and showed the need for improvement in the evaluation of toxicological risk deriving from the changing of physicochemical and toxicological properties that occur when a commercial formulation contains more than one active ingredient and several unknown co-formulants.

Synthesis, Thermotropic Properties, and Applications of Porphyrin-based Liquid Crystals: A Comprehensive Review

Abstract: Research on novel discotic molecules, which consist of a rigid core with flexible peripheral chains, has gained much attention due to their crucial role as organic photovoltaic materials, organic field-effect transistors, and semiconductors for photocurrent generation, as well as the possibility of their other optoelectronic applications. This review article describes the developments in fundamental design ideas and synthetic approaches of porphyrin-based meso and beta-substituted liquid crystals. In addition, the current review highlights the various structural alterations made by the researchers in the field of porphyrin-based mesogens and changes in properties, both for materials intended for commercially successful liquid crystal displays, including other applications, and for more basic purposes of demonstrating structure-property relationships.

Effect of glass powder on mechanical properties and electromagnetic transmission properties of high alumina cement paste

The mechanical properties and electromagnetic transmission properties of high alumina cement (HAC) paste with different glass powder (GP) contents were investigated in this paper. The effects of hydration phase, unhydrated phase, GP phase and pore phase on the dielectric properties of HAC paste were quantitatively analyzed. The results show that the strength, fluidity and setting time of HAC paste decrease with the increase of GP replacement rate. The real part, imaginary part and loss angle tangent of dielectric constant decrease. The addition of GP leads to a reduction in reflectivity and absorptivity of electromagnetic waves in the paste, while increasing transmittivity.Furthermore, the real part of the dielectric constant of each phase in the HAC paste follows the order: hydration product phase > unhydrated phase > GP phase > pore phase. With an increase in GP content, the real part of the dielectric constant of the hydration product phase increases. Finally, based on the results of vector network analysis (VNA), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM), the reasons for the changes of mechanical properties and electromagnetic properties of HAC paste under different GP replacement rates were analyzed from the aspects of phase composition, pore distribution and microstructure.

Resistant starch formation and changes in physicochemical properties of waxy and non-waxy rice starches by autoclaving-cooling treatment

ABSTRACT Resistant starch (RS) has drawn great attention from both starch research and industrial communities due to its potential health benefits. Physical starch modification approach, such as autoclaving and cooling cycle treatment, offers high potential method of enhancing resistant starch fraction due to its simplicity and cost-effectiveness. Here, the non-waxy KDML105 and waxy RD6 rice starches were physically modified by one, three, and five autoclaving and cooling cycles. The comparative impacts of the modification on the RS content and starch physicochemical properties were examined. Their native starch granules were transformed into a larger continuous matrix with suppressed thermal and pasting properties. However, modified KDML105 starch gels with higher amylose content and the presence of amylose lipid complexes were able to retrograde and maintain viscosity better than the modified RD6 starch. The RS content was also increased with the addition of treatment cycles in KDML105 starch. As a result, the RS content of native KDML105 starch was enhanced from 0.13% to 2.59% after five cycles of the treatment. The dissimilarities observed between the two modified starches could be due to the different degrees of increased proportions of ordered (R1047/1022) and double helical (R995/1022) structures, and the disruption of A- and V-type crystals. Therefore, the RS content was attributed to an interplay of alterations in ordered structure, amylose, and amylose-lipid complex during autoclaving-cooling cycles.

The Effect of Heat- and Salt Treatment on the Stability and Rheological Properties of Chickpea Protein-Stabilized Emulsions

The aim of the study was to evaluate the effect of heat- (95 °C) and/or salt (0.1 M NaCl) treatment on the physical stability and rheological properties of oil-in-water emulsions stabilized with chickpea protein concentrates (CPCs) for various purposes. Thus, the particle size distribution (PSD), shear behavior, and long-term Turbiscan stability of the prepared emulsions were examined. The oscillatory (dynamic) measurements were also performed to obtain information on the viscoelasticity of tested fluids during thermal treatment. The obtained results indicated that the emulsion stabilized with gelling CPC (eCg) was Newtonian fluid with a homogeneous structure, but susceptible to creaming. Heat-treated eCg exhibited a sol–gel transition at 86 °C and formed fine-stranded aggregates without affecting stability. In turn, heat-induced gelation of eCg in the presence of 0.1 M NaCl resulted in the formation of an aggregated, spatial gel network, stabilization of the system, and a significant change in both shear rheological properties and PSD. Contrariwise, emulsions stabilized with standard CPC (eCs) were unstable heterogeneous systems containing both fine particles < 1 μm and coarse particles of about 100 μm, exhibiting shear-thinning and yield stress. The heat-induced viscoelasticity of eCs was reversible, while heat- and salt-treated emulsions did not form a gel.

Incorporation of spray‐dried encapsulated bioactive peptides from coconut (Cocos nucifera L.) meal by‐product in bread formulation

AbstractThis study aimed to stabilize and mask the bitterness of peptides obtained from the enzymatic hydrolysis of coconut‐meal protein with maltodextrin (MD) and maltodextrin‐pectin (MD‐P) as carriers via spray‐drying. Essential (~35%), hydrophobic (~32%), antioxidant (~15%), and bitter (~45%) amino acids comprised a significant fraction of the peptide composition (with a degree of hydrolysis of 33%). The results indicated that the peptide's production efficiency, physical and functional properties, and hygroscopicity improved after spray‐drying. Morphological features of free peptides (fragile and porous structures), spray‐dried with MD (wrinkled with indented structures), and MD‐P combination (relatively spherical particles with smooth surfaces) were influenced by the process type and feed composition. Adding free and microencapsulated peptides to the bread formula (2% W/W) caused changes in moisture content (35%–43%), water activity (0.89–0.94), textural properties (1–1.6 N), specific volume (5.5–6 cm3/g), porosity (18%–27%), and color indices of the fortified product. MD‐P encapsulated peptides in bread fortification resulted in thermal stability and increased antioxidant activity (DPPH and ABTS+ radical scavenging: 4.5%–39.4% and 31.6%–46.8%, respectively). MD‐P (as a carrier) could maintain sensory characteristics and mask the bitterness of peptides in the fortified bread. The results of this research can be used to produce functional food and diet formulations.

Abstract 4388: Tumor-associated RhoA mutants interact with effectors in both GDP- and GTP-bound states

Abstract RhoA is the founding member of the Ras-homology (Rho) small GTPase family and is a master regulator for multiple cell functions. Recurrent RhoA mutations have been identified in several human cancers, particularly in leukemia/lymphoma and gastric cancer. Intriguingly, both gain-of-function and loss-of-function mutations of RhoA are present, suggesting that RhoA GTPase may have a more sophisticated role in cancer and requires more rigorous investigations. Here, we have focused on two of the gain-of-function RhoA mutations identified in Adult T cell Leukemia/lymphoma (ATLL) at residue A161 (A161P and A161V) and aim to reveal the underlying mechanistic basis for their function by biochemical and structural analyses. We found that in contrast to conventional gain-of-function RhoA mutants such as RhoAG14V and RhoAQ63L which affect the GTP-hydrolysis activity, RhoAA161P and RhoAA161Vare both fast-cycling with drastically increased nucleotide dissociation and association rates, but only slightly reduced GTP-hydrolysis activity. We solved the crystal structures of GDP-bound RhoAA161P and RhoAA161V and saw that while RhoAA161P displays impaired solvent-mediated interactions to the bound nucleotide, RhoAA161V has a more exposed nucleotide binding pocket compared to RhoAWT and RhoAA161P. Interestingly, RhoAA161P and RhoAA161Vcan interact with effector targets in the GDP-bound states. Further 1H-15N HSQC NMR study provides evidence of the active population in GDP-bound RhoAA161V. Molecule dynamics (MD) simulations show that the dynamic properties of RhoA switch regions are affected differently by the two mutations. Thus, RhoAA161V and RhoAA161P are fast-cycling mutants with distinct mechanisms, and both likely endow their GDP-bound state towards an active conformation. These findings provide a better understanding of the oncogenic role of RhoA mutations in cancer and shine light on how changes in RhoA protein dynamic properties caused by mutations may affect its function. Citation Format: Yuan Lin, Theresa A. Ramelot, Simge Senyuz, Attila Gursoy, Hyunbum Jang, Ruth Nussinov, Ozlem Keskin, Yi Zheng. Tumor-associated RhoA mutants interact with effectors in both GDP- and GTP-bound states [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4388.

Tailoring the physicochemical properties of starch: impact of integrated ultrasonic and ethanol pretreatment on the oil uptake of infrared fried ginkgo seeds.

The structural changes of starch would have a more crucial impact on oil absorption and quality changes in starch-rich fruits and vegetables during frying process with enhanced heat transfer (such as infrared frying). In the present study, the influence of integrated ultrasonic and ethanol (US + ethanol) pretreatment on oil uptake in infrared fried (IF) ginkgo seeds was evaluated regarding modifications in the physicochemical properties of starch. The pretreatment was performed with ultrasonic (40 kHz, 300 W) and ethanol osmotic (95%, v/v) treatment individually or integrated for 40 min. The mass transfer in the pretreatment was facilitated by combined ultrasound and ethanol. The swelling power, solubility, and gelatinization degree of starch was significantly increased. Low-frequency-NMR curves and images revealed that the bound water fraction in ginkgo seeds was increased and the water distribution was homogenized. The results of Fourier transform-infrared spectrum and differential scanning calorimeter revealed that the crystalline regions of starch were reduced and the thermal enthalpy was decreased after US + ethanol pretreatment. The total, surface and structural oil content in IF ginkgo seeds with US + ethanol pretreatment was reduced by 29.10%, 34.52% and 29.73%, respectively. The US + ethanol pretreatment led to a thinner crust layer with increased porosity and smaller-sized pores in the IF ginkgo seeds as observed by stereo microscopy and scanning electron microscopy. The changes in structural and physicochemical properties of starch by combined ultrasound and ethanol affect the crust ratio and pore characteristics in fried high-starch fruits and vegetables, thereby reducing oil absorption. © 2024 Society of Chemical Industry.

Drought Spatial Extent and Dependence Increase During Drought Propagation From the Atmosphere to the Hydrosphere

AbstractAs droughts propagate both in time and space, their impacts increase because of changes in drought properties. Because temporal and spatial drought propagation are mostly studied separately, it is yet unknown how drought spatial extent and connectedness change as droughts propagate though the hydrological cycle from precipitation to streamflow and groundwater. Here, we use a large‐sample dataset of 70 catchments in Central Europe to study the propagation of local and spatial drought characteristics. We show that drought propagation leads to longer, later, and fewer droughts with larger spatial extents. 75% of the precipitation droughts propagate to P‐ET, among these 20% propagate further to streamflow and 10% to groundwater. Of the streamflow droughts, 40% propagate to groundwater. Drought extent and dependence increase during drought propagation along the drought propagation pathway from precipitation to streamflow thanks to synchronizing effects of the land‐surface but decreases again for groundwater because of sub‐surface heterogeneity.

Abstract 4380: Role of kindlin-2 in prostate cancer progression and metastasis

Abstract Prostate cancer (PC) is the leading type of cancer in men accounting for more than 25% of all newly reported cancer cases and remains the second leading cause of cancer-related deaths in men in USA in 2023. The success of early treatments has resulted in a 98% 5-year survival rate for early-stage PC. However, resistance to androgen ablation can lead to metastatic castration-resistant prostate cancer (mCRPC), with a significant drop in the survival rate to ~30%. The metastatic cascade involves changes in adhesive, metabolic and signaling properties of PC cells, allowing them to survive, proliferate and thrive in their new microenvironment. Kindlin-2 (K2), a cytoskeletal adapter protein, is highly expressed in cancer, including PC cells and tumors, contributing to their tumorigenic properties. The present study focuses on three K2 functions relevant to PC metastasis: 1)Reduction in K2 levels, achieved through CRISPR/Cas9, profoundly affected the tumorigenic properties of PC cell lines LNCaP (androgen dependent), DU145, and PC3 (both androgen independent), influencing colony formation, invasion, and adhesion to integrin ligands. While reduction in K2 was observed, K1 and K3 levels in these cell lines was not altered by K2KO. 2)The E3 ubiquitin ligase, Parkin, known for its role in Parkinson’s disease, has emerged as a tumor suppressor inhibiting various cancer hallmarks. Our recently published studies showed that Parkin induces ubiquitination of specific lysines in K2, leading to the hypothesis that Parkin acts as a tumor suppressor by targeting K2 for degradation. Stable over-expression of Parkin inhibited adhesion to fibrinogen (Fg), while loss of function Parkin mutants failed to do so, supporting a role of Parkin in K2 turnover and its impact on mitochondrial dynamics. We are currently investigating the effect of K2-lysines mutants as well as loss of function Parkin mutants on the progression and metastasis of PC tumors in vivo.3)K2's established function is the regulation of integrin activation, affecting adhesion receptors' transition from low to high affinity/avidity states. The K2-integrin axis is pivotal for understanding oncogenic responses, and its role in the prostate microenvironment in PC progression and metastasis is under exploration using our newly established K2-floxed mouse. The K2-floxed mice are currently being crossed with mice harboring prostate-epithelial specific cre under control of the probasin (Pbsn) promoter. These animal studies will shed light on K2's contribution to PC development and progression in vivo, providing insights into its role in the prostate microenvironment. To sum up, this study emphasizes the crucial role of K2 in the tumorigenic properties of PC cells and tumors. By incorporating CRISPR/Cas9 and innovative mouse models, the study seeks to shed the lights on the mechanisms through which K2 contributes to PC development and progression. Citation Format: Lamyae El Khalki, Wei Wang, Neelum A. Yousaf Zai, Justin Szpendyk, Elzbieta Pluskota, Katarzyna Bialkowska, Edward F. Plow, Lucia R. Languino, Dario C. Altieri, Khalid Sossey-Alaoui. Role of kindlin-2 in prostate cancer progression and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4380.

Clay and organic compost as quality conditioners of a sandy soil in the brazilian semiarid

Due to natural and anthropic pressures of semiarid regions, like sandy texture, organic matter (OM) deficiency, water scarcity and inadequate management, we carried out an experiment under greenhouse conditions, to evaluate the effects of clay and OM addition on the quality of a sandy soil of the Brazilian semiarid. The experiment lasted 75 days, testing four clay contents (10 and 31% natural soils, 15% by clay addition to a sandy soil and 26% by mixing clay subsoil to a sandy topsoil) in the absence and presence of organic compost (7.5g.kg-1). For biological parameters, sorghum plants were used for biometric and mineral composition analysis, in addition to assessing microbial activity (BSR, MBC, and qCO2). The results showed significant differences in soil microporosity and total porosity; the field capacity and permanent wilting point correlated linearly with clay content and OM addition; potencial and exchangeable soil acidity decreased significantly in the presence of compost. Sorghum plants showed higher values of biometric attributes and lower levels of nutrients in the presence of compost. The microbial activity did not show significant differences in terms of clay content or compost addition. The cluster analysis correlated the mixed soils (26%) to the lowest clay content soil (10%), and the clay addition (15%) to the highest clay content soil (31%), showing potential as soil conditioner in association with compost, as it might promote changes in the soil quality properties of semiarid regions.

Northwestern Mediterranean Heavy Precipitation Events in a Warmer Climate: Robust Versus Uncertain Changes With a Large Convection‐Permitting Model Ensemble

AbstractTaking advantage of a large ensemble of Convection Permitting‐Regional Climate Models on a pan‐Alpine domain and of an object‐oriented dedicated analysis, this study aims to investigate future changes in high‐impact fall Mediterranean Heavy Precipitation Events at high warming levels. We identify a robust multi‐model agreement for an increased frequency from central Italy to the northern Balkans combined with a substantial extension of the affected areas, for a dominant influence of the driving Global Climate Models for projecting changes in the frequency, and for an increase in intensity, area, volume and severity over the French Mediterranean. However, large quantitative uncertainties persist despite the use of convection‐permitting models, with no clear agreement in frequency changes over southeastern France and a large range of plausible changes in events' properties, including for the most intense events. Model diversity and international coordination are still needed to provide policy‐relevant climate information regarding precipitation extremes.

Influence of glass composition on the network structure and mineralization of europium containing mesoporous bioactive glass nanoparticles

A mesoporous bioactive glass nanoparticle (MBN) containing functional elements effectively enhances its healing effect in medical applications. The MBN mainly comprises SiO2 structure and controls the composition by incorporating functional ions into the glass network, which affects the network structure and bioactivity. Europium has already been identified to have luminescence properties for drug delivery systems and positively affects osteogenic properties. Therefore, in this study, we recognize the changes in the glass network according to different compositions with the same amount of europium oxide (10 mol%).The MBN compositions with SiO2–CaO–P2O5–Eu2O3 were synthesized by sol-gel method, and we control the contents of SiO2 and CaO, respectively. The obtained Eu-containing MBNs had spherical morphology with mesoporous structure. Changes in bioactivity and mineralization properties would be investigated to apply the dental products. After soaking in simulated body fluid (SBF), Eu-containing MBNs with substituted SiO2 form an amorphous calcium phosphate phase on their surface. The results indicate that incorporating Eu in the bioactive glass network is an effective strategy for mineralization and developing novel multifunctional MBNs for bone tissue and drug delivery carriers.

Mechanical Models of Collagen Networks for Understanding Changes in the Failure Properties of Aging Skin.

Skin undergoes mechanical alterations due to changes in the composition and structure of the collagenous dermis with aging. Previous studies have conflicting findings, with both increased and decreased stiffness reported for aging skin. The underlying structure-function relationships that drive age-related changes are complex and difficult to study individually. One potential contributor to these variations is the accumulation of nonenzymatic crosslinks within collagen fibers, which affect dermal collagen remodeling and mechanical properties. Specifically, these crosslinks make individual fibers stiffer in their plastic loading region and lead to increased fragmentation of the collagenous network. To better understand the influence of these changes, we investigated the impact of nonenzymatic crosslink changes on the dermal microstructure using discrete fiber networks representative of the dermal microstructure. Our findings suggest that stiffening the plastic region of collagen's mechanical response has minimal effects on network-level stiffness and failure stresses. Conversely, simulating fragmentation through a loss of connectivity substantially reduces network stiffness and failure stress, while increasing stretch ratios at failure.

Surface modification of natural leather using RF plasma discharge

Radiofrequency (RF) low-pressure plasma has been applied to improve natural leather's wettability and water absorption. The plasma was generated using RF discharge of the Ar-He gas mixture at 60 and 120 W power using different treatment times (30, 60, 120, 180, and 300s). Before and after treatment, the contact angle, surface free energy, and water absorption ratio were measured. It was observed that a 300s plasma treatment time and plasma power 60 and 120 W is enough to decrease the water contact angle from 83.56 for an untreated sample to 0°. The surface-free energy and the water absorption ratio increase with an increase in the treatment time and plasma power. The findings demonstrate that plasma treatment increases the wettability of the surface of leather samples. In addition, the change in leather properties was analyzed by scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry, Fourier transform infrared spectroscopy.

A theoretical study on 1H-indole-2,3-dione complexes with lithium, sodium, and potassium cations.

A comparative study of the change in different properties of electronic and structural of the free 1H-indole-2,3-dione molecule and its complexes has been obtained. HOMA analysis was performed to investigate the effects of lithium sodium and potassium cations on the aromaticity of lithium sodium and potassium complexes of 1H-indole-2,3-dione. Several 1H-indole-2,3-dione complexes with lithium, sodium, and potassium cations were optimized at the B3LYP/6-311G(d,p) level. The cation and π interaction has been investigated from different aspects, including interaction energy calculations, charge transfer values, and changes in the aromaticity of the ring upon complexation. The charge transfer and natural population analysis for the complexes were performed with the natural bond orbital (NBO) analysis. The properties of bond critical points in complexes were studied by applying the quantum theory of atoms in molecules (QTAIM). Finally, the aromaticity change of phenyl induced upon complex formation was evaluated by applying the harmonic oscillator model of aromaticity (HOMA). [Li-INa]+ and [[Li-INb]+ were optimized with the wB97XD function using a version of Grimme's D2 dispersion model, and the absorption energy was compared with the calculation made with the B3LYP functional.

Different responses of lipids and lignin phenols to nitrogen addition in meadow grassland soil

Abstract Purpose Nitrogen (N) enrichment can affect the composition and stability of soil organic carbon (SOC) pools by altering vegetation and soil properties. However, the response of plant-derived carbon components in soil to different N addition levels is unclear. We investigated the changes and potential driving processes of plant-derived carbon components (especially lignins and lipids) in meadow grassland soils under long-term N addition in eastern Inner Mongolia, China. Materials and methods Biomarker technology was utilised to analyse changes in plant-derived carbon components (C>20 free lipids, bound lipids, and lignin phenols) in soil under different N addition levels, including changes in soil chemical properties, enzyme activity, plant biomass, and diversity under N addition, as well as the specific pathways involved. Results and discussion We found that high levels of N addition significantly reduced the concentration of soil lignin phenols whereas increased the accumulation of lipids (free and bound lipids). Compared with changes in plant biomass and diversity, soil chemical properties and enzyme activity play a more significant role in regulating the accumulation and degradation of plant-derived carbon. Structural equation modelling (SEM) showed that decreases in lignin phenol concentration were related to specific biochemical decomposition processes (increased polyphenol oxidase activity and decreased C/N). The increase in lipids associated with the protective effects of minerals mediated by pH. Conclusions In general, plant-derived carbon components showed inconsistent responses to N addition, lignin phenol concentration decreased and lipid concentration increased, which was mainly related to the change of soil biochemical properties. Plant-derived carbon components only showed significant changes under high N addition levels. Furthermore, our research indicates that SOC sequestration and functioning are highly dependent on soil biochemical properties, which weakens the influence of changes in plant carbon input on soil carbon storage.

Study on the Mechanical Degradation and Destruction Characteristics of Coal Oxidation

ABSTRACT Deep coal bodies are often in high stress and high temperature environments. To study the effects of stress and temperature on the mechanical degradation and failure characteristics of coal samples, nuclear magnetic resonance experiments were carried out before and after coal sample oxidation to analyze the effect of oxidation on the porosity of the coal samples. Through mechanical property experiments, the changes in the mechanical properties of the coal samples at different oxidation temperatures is analyzed. Then coal samples of different particle sizes are screened and statistically analyzed to determine the relationship between the fractal dimension of the broken block size and the oxidation temperature. A stress model for the oxidized coal samples is established to analyze its mechanical degradation and its breaking mechanism. Based on the results, As the oxidation temperature increases, The total porosity of the coal samples show an overall increasing trend, the elastic modulus, secant modulus, Poisson’s ratio, and shear modulus show a downward trend, and the destructive strain energy density decreases from 43.33 kg•m−3 to 15.47 kg•m−3, indicating the oxidized coal sample increases in plasticity and decreases in stiffness, resulting in a decrease in the amount of load the sample can carry. The fractal dimensions of the broken block size from raw coal to 200°C coal samples are 2.008, 2.092, 2.150, 2.159, 2.175, 2.183, 2.314, and 2.328. Oxidation leads to the formation a network of tiny fractures inside the coal samples; thus, the broken block size becomes more complex with worsened integrity. A model for the ability of the oxidized coal samples to resist destruction is established, and the diameters of unoxidized areas in oxidized coal samples are calculated to be 45.053, 44.956, 43.031, 41.931, 37.442, 28.081 and 13.778 mm. An analysis of the breaking mechanism of oxidized coal samples was carried out. Our results are beneficial for the safe operation of deep coal seam mining.

Evaluation of Low-Pressure Cold Plasma Effect on Phytonutrients, Drying and Microstructural Characteristics, and Changes in Microbial Load of Fresh and Hot-Air-Dried ‘Heidi’ Mango

AbstractAlternative pre-treatment strategies before drying offer the prospect to minimize drying time, replacing the use of chemicals, and preserving quality of dried fresh products. This study explored the application of low-pressure atmospheric cold plasma (CP) for 5- and 10 min (CP5 and CP10) as pre-treatments prior to processing and hot air drying (60 °C) of ‘Heidi’ mango, while non-treated samples served as control. Changes in tissue microstructure and physicochemical properties, bioactive compounds, and microbial load were evaluated, and seven thin layer drying models were applied. Scanned electron microscope images showed that CP pre-treatments altered the tissue microstructure of dried mango slices compared to control. ‘Heidi’ mango slices with the initial moisture content of 80 ± 0.2% on a wet basis was reduced by 81% and 76% in dried CP5 and CP10 samples, respectively. Drying time was reduced by 20% for CP pre-treated samples in comparison to control samples, and the drying behavior of ‘Heidi’ mango slices was best described by the Logarithmic model (R2, 0.9999 and RMSE, 0.0122). Colour attributes were best retained by sodium metabisulphite (SMB) pre-treated samples, followed by CP5 pre-treated, which performed better than CP10 and control (p ≤ 0.05). Highest total flavanols (15.0 ± 0.4 mg CE 100 g−1) and higher total phenolics (1528.2 ± 23.6 mg GA 100 g−1) were found in CP5 pre-treated samples compared to the control (p ≤ 0.05). Lowest antioxidant activities were found in CP10 pre-treated samples compared to the control (p ≤ 0.05). CP-pretreatment and drying resulted in ≥ 2 Log reduction in microbial load on mango slices. These results demonstrate to the role players in mango value addition chain, the potential of low-pressure CP pretreatment in enhancing/maintaining the bioactive compounds, reducing drying time and microbial load.