Changes In Mineral Composition Research Articles

Effect of high temperature on the mixed mode I-II fracture characteristics of hot-dry rock

To investigate the variation law of rock fracture characteristics with temperature in hot-dry reservoirs, the pure mode I, pure mode II and mixed mode I-II loading experiments were carried out on sandstone and granite at room temperature and after high-temperature (100 °C, 300 °C, 500 °C and 700 °C) treatment by using the central cracked Brazilian disk (CCBD) specimen. The changes of parameters such as failure load, fracture toughness and fracture envelope with temperature were discussed, and the changes of rock mineral composition and fracture surface morphology were analyzed by X-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively. The results showed that the influence of temperature on the fracture characteristics of sandstone and granite presents different evolution laws.With the increase of temperature, the failure modes of sandstone and granite all change from brittle failure to ductile failure, but the critical temperature of the transition is different. Granite shows obvious ductile failure characteristics at 500 °C, while sandstone shows slight ductile failure characteristics at 500 °C.The failure load and fracture toughness of sandstone increase first and then decrease with the increase of temperature, which indicates that within a certain range, the temperature has a toughening effect on sandstone, and can improve its failure resistance. However, the failure load and fracture toughness of granite always decrease with the increase of temperature, which indicates that the temperature only has a deteriorating effect on granite. In the range of 100 °C to 500 °C, the temperature enhances (sandstone) or weakens (granite) the mode I fracture toughness of rocks more than it enhances or weakens the mode II fracture toughness. However, when the temperature is 700 °C, the temperature weakens the mode II fracture toughness more than the mode I fracture toughness. The area enclosed by the fracture envelope of sandstone first increases and then decreases with the increase of temperature, while the area enclosed by the fracture envelope of granite decreases with the increase of temperature. As the temperature increases, the tortuosity of the crack paths in sandstone and granite increases, the cross-section morphology becomes rougher, and the internal fissures and fragmentation increase.

Experimental Study on Salt-Bearing Sandstone Samples Under the Change of Temperature and Humidity Cycle

ABSTRACT Salt crystallization is a common type of disease in grottoes. Due to the change in temperature and humidity, the soluble salt originally existing in sandstone will have a negative impact on the protection of rock relics. In this study, sandstone samples containing Na2SO4 solution and distilled water were used to study the difference in sample damage under the condition of temperature and humidity cycle changes. It was found that the damage degree of samples containing soluble salts was much higher than that of salt-free samples, especially under the influence of freeze-thaw cycles. With the increase of freeze-thaw cycles, the internal friction angle and wave velocity of sandstone decrease linearly, while the surface hardness, tensile strength, and cohesion decrease exponentially. In addition, the damage caused by freeze-thaw cycles and dry-wet cycles develops from the inside to the outside of the rock sample, which is manifested by the increase in the number of macropores and the emergence of new pores. The different combinations of several effects lead to different changes in pore structure and mineral composition of the samples under the four conditions. The research results are helpful in providing a scientific basis for the disease control of stone cultural relics.

Aluminium substitution affects jarosite transformation to iron oxyhydroxides in the presence of aqueous Fe(II)

Jarosite is an abundant mineral in acidic environments, often found in acid sulfate soil (ASS) and acid-mine drainage (AMD). As a store of Fe, K, S and acidity, and a scavenger for major and trace elements, jarosite plays an important role in the biogeochemistry of acid sulfate environments. When ASS and AMD become anoxic, reducing conditions can set in, producing conditions that are outside the thermodynamic stability field of jarosite. In this study, we investigated the transformation of synthetic and natural jarosite with various degrees of Al-for-Fe substitution under circumneutral anoxic conditions in the presence of Fe(II), to understand the rates and pathways of jarosite and Al-jarosite transformation, the role of competing transformation pathways, the fate of Al during transformation and the different reactivity of natural and synthetic Al-jarosite. Synthetic jarosite (containing 0 %–7 % Al-for-Fe substitution) and a natural Al-substituted jarosite sample from an ASS in Thailand were suspended in solutions of 57Fe(II) at pH 7 for 24 h under anoxic conditions. The chosen experimental conditions mimic the Fe(II) concentrations and pH found in flooded ASS under reducing conditions. Changes in mineral composition of the suspensions were determined by Rietveld analysis of X-ray diffraction patterns at six time points. The fate of Al was determined by XRD, Raman spectroscopy and energy dispersive X-ray spectroscopy analysis of the jarosite and product minerals. Different transformation pathways that occurred simultaneously were traced by using 57Fe Mössbauer spectroscopy and aqueous Fe isotope composition. The analysis showed that 7 % Al-for-Fe substitution in jarosite more than halved the mineral transformation rate compared to unsubstituted jarosite, regardless of the Fe(II) concentrations. Indeed, 7 % Al-for-Fe substitution had a greater effect on the transformation rate than an order-of-magnitude decrease in the Fe(II) concentrations in all Al-for-Fe substitution treatments. The transformation products in all samples were goethite, lepidocrocite and ferrihydrite, with minor amounts of magnetite forming from jarosite with no or low Al-for-Fe substitution reacted with high Fe(II) concentrations. Lepidocrocite was the dominant product in reactors without aluminium, but lepidocrocite was not strongly enriched in 57Fe, suggesting that it may not have formed exclusively from Fe in solution during the Fe(II)-catalysed transformation of other minerals. In high-Al systems, lepidocrocite appeared to be a sink for Al, although its formation in Al-rich samples was suppressed. Natural jarosite reacted more than an order of magnitude more slowly than the synthetic jarosite and Al-jarosite, indicating that the properties of the synthetic jarosite do not completely account for the stability of natural jarosite under anoxic circumneutral conditions. The results provide an important baseline for understanding the drivers of jarosite transformation or stability in ASS and AMD.

Peculiarities of biochemical and mineral composition of lettuce <i>Lactuca sativa</i> L. grown from seeds after long-term storage in the International Space Station

Seed storage of agricultural crops in the conditions of International Space Station (ISS) is an effective method of quick plant breeding aimed to enhance the adaptability, and improve the biologically active compound accumulation and crop yield. Biochemical and mineral composition (ICP-MS) of lettuce grown in greenhouse from seeds stored for one year at the ISS was assessed. High varietal differences in lettuce tolerance to the effect of micro-gravity and radiation were evaluated using the values of yield, biometrical parameters, antioxidant status and plant mineral composition. Among the cultivars studied, i.e. Petrovich, Synthesis, Moskovsky parnikovy, Picnic, Cavalier and Bouquet, only the cvs. Retrovich, Synthesis, Moskovsky parnikovy and Picnik retained seed viability. Significant yield increase was recorded for the cv. Moskovsky parnikovy, while the cvs. Petrovich, Synthesis and Picnic demonstrated a tendency to the yield decrease. Improvement of photosynthetic pigment accumulation due to seed space storage was recorded for the cv. Moskovsky parnikovy and, particularly, the latter cultivar differed from the other cvs. due to the significantly higher proline level and lower MDA levels in leaves. Though space stress did not cause any significant decrease in antioxidant accumulation of plants, the latter demonstrated valuable changes in mineral composition. Among the 23 elements tested, V, Se. Fe and Cr showed higher concentrations compared to those in the control plants. Positive correlations between Ca, Sr, Cd, Cp, Mg, Mo and Pb were recorded (r > 0.9; p < 0.001).

Study on the Influence of Supercritical CO2 with High Temperature and Pressure on Pore-Throat Structure and Minerals of Shale.

Injection of carbon dioxide offers substantial social and economic advantages for reduction of carbon emission reduction. Utilizing CO2 in shale formations can significantly enhance the extraction of shale oil or gas. Conducting fundamental research on how CO2 affects shale rock's physical properties is crucial for enhancing its porosity and permeability. Particularly for deep shale layers, the effects of supercritical CO2 on shale physical properties should be investigated at a high temperature and pressure, differing from the standard conditions applied in shallower layers. A study examined the impact of supercritical CO2 under such conditions on the pore-throat structure and mineral composition of the shale. The experimental parameters included immersing shale rock in supercritical CO2 at pressures ranging from 10 to 70 MPa and temperatures between 55 and 95 °C. This study evaluated changes in mineral composition, pore-throat structure (using scanning electron microscopy and nitrogen adsorption tests), and the porosity and permeability of the shale rocks. Findings indicated that the dissolution of CO2 altered the relative content of certain minerals. The average quartz content rose and, potassium feldspar and the average contents of plagioclase declined conversely. When increasing the pressure, an increase in the relative content of I/S mixed layer and a decrease in illite content were observed and kaolinite content experienced minor changes. When increasing the temperature, kaolinite, I/S mixed layer, and chlorite all exhibited a decreasing trend with increasing temperature, while the relative contents of illite increased. Some of the pores become rounded in a high-magnification view under the impact of CO2 dissolution. Additionally, the Brunauer-Emmett-Teller specific surface area, pore volume, porosity, and permeability generally improved with increasing pressure and temperature. With the temperature and pressure of CO2 increased, the curves of nitrogen absorption had moved first upward and then downward. However, under specific CO2 conditions, the permeability enhancement effect could diminish or even negatively impact the shale's permeability. These findings underscore the need to optimize supercritical CO2 injection parameters under high-temperature and high-pressure conditions. This research aims to provide theoretical guidance for the efficient use of CO2 in deep shale applications to increase the shale gas output.

Experimental simulation of water-coal interactions during liquid CO2 injection into coal beds

Injection of liquid CO2 (LCO2) into coal reservoirs is an extremely effective way to enhance coalbed methane recovery and storage. This study aimed to investigate the changes in mineral composition and content during the chemical reaction between coal samples and weakly acidic fluids dissolved in LCO2. Therefore, in this study, simulating the formation temperature (30 °C), three types of coal samples with different metamorphic degrees (lignite, anthracite, and bituminous coal) were selected for CO2–H2O-coal interaction leaching experiments under various pressure conditions (1 MPa, 3 MPa, 5 MPa). X-ray diffraction analysis (XRD) was used to test coal samples' mineral composition and content before and after LCO2 injection under different pressure conditions. Scanning Electron Microscope (SEM) was used to observe the evolution pattern of surface characteristics before and after the dissolution of the coal body by LCO2. The results showed that minerals such as kaolinite, illite, quartz, and potassium feldspar in the three coal samples underwent mineral transformation during the reaction process at different dissolution pressures, and the content changed significantly in the early stage of the reaction. The initial content of kaolinite in the bituminous coal (16.5%) increased to 23.8%, 26.7%, and 25.2% respectively under different leaching pressures of 1 MPa, 3 MPa, and 5 MPa. Carbonate minerals dissolved rapidly in the initial stages of the reaction, the initial content of calcite, a carbonate mineral in the anthracite (9.8%), decreased to 4.2%, 3.8%, and 2.4% respectively under different leaching pressures of 1 MPa, 3 MPa, and 5 MPa. Similarly, the initial content of siderite decreased from 6.8% to 2.8%, 2.3%, and 1.6% respectively. LCO2 pressure had a significant influence on the reaction. These results advance our understanding of LCO2 dissolution of minerals in coal.

Meat productivity and quality of meat and liver of broiler chickens after consuming diet with mineral supplements containing chelates of cuprum, iron, zinc, and manganese

Poultry farming plays an important role as a producer of high-quality animal protein, which can solve issues of protein deficit among the population. Genetic growth potential of broiler chickens can be maximized through regular supply of microelements, especially chelate aminoacids. Those compounds improve metabolic processes in the body and increase increments in live mass and slaughter-yield of meat. The main objective of the study was identifying effects of mineral supplements with chelate microminerals on meat productivity of broiler chickens, quality of breast and thigh muscles, and content of mineral compounds in meat and liver. The studies were carried out on Kobb-500 broiler chickens, divided into three groups, each comprising 25 individuals. The experiment lasted from day 1 to day 42 of raising poultry. Broilers of the control group received the basic diet balanced in nutrients; the diet of birds of the second group was supplemented with Kronotsyd-L with chelates of copper, iron, zinc, and manganese in calculation of 0.25 mL/L of water, and chickens of the third consumed a diet with copper glycinate in calculation of 0.30 mL/L of water. Subject to mineral supplements with chelate microelements, the chickens had the highest mean-daily increments of live mass, slaughter yield, and yield of breast muscles. Use of mineral supplements in the diet of broiler chickens affected the quality of their meat, in particular its chemical composition. Those supplements led to changes in mineral composition of meat, influencing the concentrations of individual minerals in the tissues of the birds. Since minerals are important components of protein metabolism, the supplements augmented the content of dry matter and protein in meat. In the broiler chickens that had been receiving copper glycinate, the breast muscles had statistically significant increases in the mass shares of dry matter and protein. We found decrease in the content of fat in the breast and thigh muscles and the liver subject to copper glycinate and Kronotsyd-L with chelates of copper, iron, zinc, and manganese. This indicates improvement of the quality of meat and the liver. Use of mineral supplements with chelated microelements increased the ash content in dry matter because of higher concentrations of phosphorus, calcium, magnesium, iron, and manganese.

Experimental study on mine water purification mechanism for broken coal and rock masses in the underground reservoir of ecologically vulnerable mining area.

Water-rock interaction mechanism and water purification capacity of broken coal and rock masses are very important for the efficient operation of the underground reservoir. In this paper, a water purification simulation device for an underground mine reservoir was designed. The experimental study on the dynamic interaction between broken coal and rock masses and mine water was carried out. The water purification mechanism is analyzed from the changes in rock mineral composition and mine water quality before and after the test. The results show that after the broken coal and rock mass purification, the water turbidity and the concentration of chlorides and suspended solids decreased obviously. The water purification capacities of mudstone and sandstone are stronger than that of coal samples. After 60days of reaction between the working face sewage and the broken samples (mudstone, sandstone, and coal), the turbidity, chromaticity, and residual chlorine decreased by > 90%, 90%, and 60%, respectively; and COD decreased by 35.29%, 30.59%, and 28.99%, respectively. While the TDS and the total hardness increased by about 40%, 30%, and 10% for the mudstone, sandstone, and coal, respectively. It shows that coal also has the worst degradation performance. The water purification effect of broken coal and rock masses has a significant time effect. The early stage of water-rock interaction is dominated by mineral dissolution, and the middle stage is dominated by precipitation and adsorption. The pH value of the solution has a certain influence on the ion change. In the later stage, the water-rock interaction is weak in a dynamic equilibrium state, and the change in the mine water quality index is not obvious. Considering the influence of rock lithology on water quality and the law of water-rock interaction time, the construction site selection and water storage time optimization of underground reservoirs in Jinjie Coal Mine were carried out, respectively.

Long-term liming changes pasture mineral profile

There is limited information on changes of pasture mineral concentrations over the long-term in response to liming. A long-term field experiment was conducted to assess the influence of lime application on (a) changes in pasture mineral composition over time; and (b) key pasture mineral concentrations and ratios important to animal health. Perennial and annual pastures with or without lime application were sampled annually over 12 years and analysed for macro- and micro-minerals. Mineral ratios and indices were calculated to assess the potential impact on animal health. Liming increased the concentrations of calcium, sodium and silicon, but decreased the concentrations of micro-nutrients including copper, zinc and manganese. The same trend was found in both annual and perennial pastures although there were some fluctuations between years. Liming increased the calcium:phosphorus ratio and the dietary cation–anion difference but reduced the tetany index on both annual and perennial pastures. These findings suggest a potential benefit to improve animal health outcomes for some disorders on the limed pastures. However, the reduced concentrations of some trace elements following liming potentially decreases antioxidant capacity and requires further research.

Pilanesbergite: a new rock-forming mineral occurring in nepheline syenite from the Pilanesberg Alkaline Complex, South Africa

Abstract. The new mineral pilanesbergite, with the ideal formula Na2Ca2Fe2Ti2(Si2O7)2O2F2, was found in a nepheline syenite, locally known as green foyaite, from the Pilanesberg Complex located in the North West Province of South Africa. Pilanesbergite occurs in green foyaite in association, and partly intergrown, with aegirine. The two minerals share an assemblage of inclusions, comprising euhedral nepheline, titanite and minor sodalite. Pilanesbergite belongs to the wöhlerite group and is isomorphic with låvenite, normandite and madeiraite. It is related to these species through the homovalent chemical substitutions Mn2+↔Fe2+ and Zr4+↔Ti4+. The empirical formula calculated on the basis of 18 anions is Na2.00(Ca1.74Na0.26)Σ2.00(Fe1.00Mn0.52Ca0.49Zr0.05)Σ2.06(Ti1.69Zr0.14Mg0.09Nb0.08)Σ2.00(Si2O7)2.00O1.84F2.16 (Z=2). The new mineral is translucent with a brown orange colour and a brownish streak. The Mohs hardness is estimated between 5 and 6 by comparison with låvenite, and no cleavage is observed. Measured and calculated densities are Dmeas=3.47 g cm−3 and Dcalc=3.40 g cm−3. In the thin section the pleochroism is strong, between straw yellow and orange red, while in immersion the strong pleochroism is observed between light yellow (α) and yellowish orange (γ). The crystals are optically biaxial (+) with α=1.743(3), β=1.768(3), γ=1.795(5) and a 2 V angle close to 90∘. The crystal structure is monoclinic (P21/a), with the unit-cell parameters a=10.7811(2), b=9.7836(1), c=7.0348(1) Å, β=108.072(2)∘ and V=705.41(2) Å3, and has been refined to R1=2.06 %. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (h k l)] are 3.219 (60) (310), 2.851 (100) (12-2), 2.802 (51) (320), 2.743 (27) (22-2), 2.423 (19) (40-2) and 1.723 (19) (44-2). Pilanesbergite formed under relatively reducing conditions from an agpaitic nepheline syenite magma that had evolved by fractional crystallization mainly of aegirine. Further crystallization of arfvedsonite caused an increase in oxygen fugacity and a change towards higher Mn/Mn+Fe of the magma, causing a change of mineral composition from pilanesbergite towards normandite.

Impact of wettability on capillary phase trapping using pore-network modeling

The impact of rock wettability on phase mobility and capillary trapping is significant in the valuation of geologic carbon sequestration scenarios. Wetting conditions of CO2/brine/rock systems can vary from site to site and over time due to changes in temperature, pressure, salinity, mineral composition and surface roughness. Therefore, effective predictability of CO2 mobility and trapping in underground formations requires a thorough exploration of the relationship between wetting conditions and phase saturation over a wide range of contact angles. In this paper, we use pore-network modeling to investigate the effect of wettability on phase mobility and capillary trapping. We simulate different wetting and nonwetting conditions during secondary flooding cycles where the initial phase saturations are varied significantly. Characteristic initial-residual (IR) saturation curves and the locus of residual phase connectivity and saturation are determined for each wettability condition.Simulations show that when the receding phase is the wetting phase, there is reduced trapping of that phase owing to piston-like advance by the nonwetting phase and sustained layer flow of the wetting phase. Such flow regimes cause nonlinearity in the characteristic initial-residual (IR) saturation curve, which is not captured by traditional trapping models. A proposed extended Land-based model matches the IR trends for all wettabilities. Simulations also show that the loci of residual phase saturation and phase connectivity are a strong function of wettability. When the receding phase is strongly nonwetting, the locus remains nearly constant in phase connectivity, while at increasingly wetting conditions, the locus forms a closed-loop in the saturation-connectivity space, where the endpoint of the locus is constrained by pore topology as residual saturations approach low values.

Phenotypic characterization, plant growth and development, genome methylation, and mineral elements composition of neotetraploid lettuce (Lactuca sativa L.).

Stable neotetraploid lines of lettuce (Lactuca sativa L.) were produced from three phenotypically distinct cultivars (Annapolis, Eruption, Merlot) and an advanced breeding line (SM13-L2) using colchicine treatment of seeds or young seedlings. When tested under the greenhouse and field conditions, neotetraploids initially grew more rapidly than their diploid progenitors, however they reached their reproductive stage (bolting, flower bud formation, and flowering) substantially later. Seeds production on neotetraploids was delayed by more than 30 days compared to diploids. Tetraploid plants had fewer, but larger stomata and leaves, less chlorophyll per area, higher photosystem II photochemical efficiency, generally lighter root system, and produced less than 1% of seeds in comparison with diploids. Field-grown neotetraploids of all lines displayed a significant reduction in tipburn (1.8% vs. 22.2%, respectively), a highly undesirable physiological disorder. Changes in leaf and root mineral composition were detected in neotetraploids. Several elements were found in lower abundance than in diploids, most notably iron, calcium, and silicon. Whole genome bisulfite sequencing (WGBS) revealed 498 differentially methylated regions (DMR), with 106 of these regions having at least 50% difference in the level of methylation between neotetraploids and their diploid progenitors. At least 18 of the most prominent DMR were detected in proximity to genes predicted to be involved in plant development or reaction to biotic and abiotic stressors. Because neotetraploid lines have low seed production, they are not suitable for commercial cultivation. They can be used, however, in research to study the factors contributing to tipburn, traits affected by stomata size or density, and the effect of ploidy on resistance to environmental stressors.

Temperature dependence of mechanical properties and damage evolution of hot dry rocks under rapid cooling

Understanding the differences in mechanical properties and damage characteristics of granitoid under high temperatures is crucial for exploring deep geothermal resources. This study analyzes the evolution of the acoustic emission (AE) characteristics and mechanical parameters of granodiorite and granite after heating and water cooling by uniaxial compression and variable-angle shear tests under different temperature gradients. We identify their changes in mesostructure and mineral composition with electron probe microanalysis and scanning electron microscopy. Results show that these two hot dry rocks have similar diagenetic minerals and microstructure, but show significantly different mechanical and acoustic characteristics, and even opposing evolution trends in a certain temperature range. At the temperatures ranging from 100 °C to 500 °C, the compressive and shear mechanical properties of granodiorite switch repeatedly between weakening and strengthening, and those of granite show a continuous weakening trend. At 600 °C, both rocks exhibit a deterioration of mechanical properties. The damage mode of granite is characterized by initiating at low stress, exponential evolutionary activity, and intensified energy release. In contrast, granodiorite exhibits the characteristics of initiating at high stress, volatile evolutionary activity, and intermittent energy release, due to its more stable microstructure and fewer thermal defects compared to granite. As the temperature increases, the initiation and propagation of secondary cracks in granodiorite are suppressed to a certain extent, and the seismicity and brittleness are enhanced. The subtle differences in grain size, microscopic heterogeneity, and mineral composition of the two hot dry rocks determine the different acoustic-mechanical characteristics under heating and cooling, and the evolution trends with temperature. These findings are of great significance for the scientific and efficient construction of rock mass engineering by rationally utilizing different rock strata properties.

Cross-scale study of pore fractal characteristics and the pore structure of weathered granite

Weathering of granite leads to weakening of its crushing and mechanical properties, as well as changes in mineral composition. In order to investigate the correlation between the effects of weathering on granite and the characterization of the pore structure at the micro- and fine-scale, in this paper the pore structure of weathered granite is tested by the NMR technique. The pore distribution characteristics of weathered granite were explored in conjunction with T 2 spectral relaxation time and fractal theory. The microstructure of weathering-prone granite was monitored using scanning electron microscopy equipment. The results show that the pores can be classified into the three categories of small, medium and large pores based on their pore size distribution characteristics. Weathered granite has fractal features in the mesopores and macropores. Compared with unweathered granite, weathered granite has significantly more small pore throats and fewer medium and large pore throats, which expand into microfissures and micropores under conditions of weathering. The microstructure of weathered granite is mainly flaky and shell-like, with good connectivity, resulting in the poor overall structure of weathered granite.

Progressive microstructural evolution characteristics and weakening mechanism of coal exposed to acid mine drainage (AMD)

This study aims to analyze the extent of softening structural deterioration of coal pillars over time when exposed to acid mine drainage (AMD) from abandoned pits. The research involves using microscopic recognition techniques on coal samples and hydrochemistry tests in solution to identify changes in mineral compositions and microstructure parameters quantitatively. The study examines the micro-scale changes in microstructural hydro-chemical damage processes in coal samples. Based on the findings, the decrease in pH of the acidic pit effluent leads to degradation in the physical microstructural characteristics of the coal. Specifically, there is a 6.90% increase in the fractal dimension and a 23.33% rise in the area porosity. Similarly, the chemical parameters of the coal also undergo significant changes. The thickness of the aromatic layer in the coal decreases significantly, while the average diameter of the aromatic layer increases by 16.9%. The aromaticity of the coal increases, indicating noticeable deterioration of the matrix layer, particularly fragmentation. Moreover, the solution characteristics reflect the progressive coal deterioration, including increased metal ions in the soaking solution, the transformation of divalent iron to trivalent iron, and a continuous rise in sulfate content. These results have implications for assessing and maintaining load-bearing structures in underground abandoned pits subjected to long-term immersion.

Effects of pH on Disintegration Characteristics of Gypsum Karst Breccia under Scouring Action

Water–rock interactions and scouring actions are recognized key factors that significantly influence the disintegration of rock on the surface of slopes. However, the research on rock disintegration, specifically under the action of scouring, is limited, which makes it difficult to understand the characteristics of rock disintegration. Therefore, in this study disintegration tests were performed on the gypsum karst breccia collected from the Zhoukoudian site in Beijing, using a self-made disintegration test device. Further, this study investigated the impact of solution pH, flow velocity, and the number of cycles on the characteristics of rock disintegration. The changes in pore structure, microstructure, and mineral composition of the rock were analyzed using nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectrometer (ICP-OES) methods. The findings reveal that the cumulative relative disintegration amount of the gypsum karst breccia experiences an increase as the pH value of the soaking solution decreases and the number of cycles increases. Once a specific flow rate is attained, the cumulative relative disintegration amount stabilizes (about 73%) and no longer exhibits significant changes. This phenomenon signifies the presence of a stabilizing flow rate for disintegration. The stable flow rate concerning rock disintegration is influenced by both the solution’s pH and the number of cycles. Following acid contamination, the rock sample’s particle morphology undergoes disruption, leading to the dissolution of cement. This, in turn, leads to an augmented release of Ca2+, Al3+, and Ma2+ ions in the solution, intensifying the disintegration of the rock samples. Conversely, alkali contamination prompts secondary cementation, mitigating localized damage. This results in a marginal increase in the calcite content within the rock samples (from 15.3% to 19.2%), while the release of Ca2+ in the solution experiences a decrease. Additionally, there is a slight increase in the release of Al3+ (a maximum increase of 1.71 mg/L), which minimally inhibits the disintegration of the rock samples. Notably, the rock disintegration predominantly occurs around macropores, and the effect of solution pH on the disintegration characteristics and stable flow rate is primarily due to the changes in the relative proportion of macropore volume in the rock samples. The findings of this study have significant implications for the prediction and control of slope-related issues.

Investigation of Lactation Period and Technological Treatments on Mineral Composition and IR-Profiles of Donkey Milk by Chemometrics

Donkey milk represents an efficient substitute for human milk in infants’ diets being unlikely to cause allergic reactions. In this study, different donkey milks were collected at two lactation times (T0 and T1), subjected to freezing–thawing and freeze-drying, and analyzed by Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP-OES) and ATR-FT-IR. The data collected on freeze–thaw (FT-) and reconstituted (R-)milks were investigated by ANOVA–Simultaneous Component Analysis (ASCA) and Principal Component Analysis (PCA). The following concentrations (µg/mL) for FT and R-milks, respectively, at T0, were found: Ca: 712 ± 71, 600 ± 72; Fe: 0.7 ± 0.3, 0.1 ± 0.1; K: 595 ± 49, 551 ± 59; Mg: 75 ± 5, 67 ± 4; Na: 117 ± 16, 114 ± 16; P: 403 ± 30, 404 ± 38; Zn: 1.6 ± 0.2, 1.6 ± 0.3. At T1, the concentrations (µg/mL for FT and R-milks, respectively) were: Ca: 692 ± 60, 583 ± 43; Fe: 0.13 ± 0.02, 0.13 ± 0.03; K: 641 ± 71, 574 ± 61; Mg: 72 ± 4, 63 ± 1; Na: 116 ± 9, 109 ± 8; P: 412 ± 30, 405 ± 24; Zn: 1.6 ± 0.3, 1.6 ± 0.3. ASCA demonstrated the treatment has a substantial effect, and PCA revealed that the largest quantities of metals, specifically Fe, Mg, and Ca for T0 and K, P, and Na for T1, are present in the FT-milk samples. The IR spectra of FT- and R-milks revealed no macroscopic changes among them or between lactation periods, indicating this technique may not suitably capture variability in lactation or conservation processes in donkey milk. Despite the relatively small sample size, this study offers insight on the mineral composition changes in donkey milk and emphasizes the significance of milk preprocessing and the lactation period on it.

Dental characteristics of patients with four different types of skeletal dysplasias.

Skeletal dysplasia (SD) comprises more than 450 separate disorders. We hypothesized that their dental features would be distinctive and investigated the tooth characteristics of four patients with different SDs. Four SD patients with molecularly confirmed diagnoses, Pt-1 acromicric dysplasia, Pt-2 hypophosphatasia and hypochondroplasia, Pt-3 cleidocranial dysplasia, and Pt-4 achondroplasia, were recruited. A tooth from each patient was evaluated for mineral density (micro-computerized tomography), surface roughness (surface profilometer), microhardness, mineral contents (energy-dispersive X-ray), and ultrastructure (scanning electron microscopy and histology), and compared with three tooth-type matched controls. Pt-1 and Pt-3 had several unerupted teeth. Pt-2 had an intact-root-exfoliated tooth at 2years old. The lingual surfaces of the patients' teeth were significantly smoother, while their buccal surfaces were rougher, than controls, except for Pt-1's buccal surface. The patients' teeth exhibited deep grooves around the enamel prisms and rough intertubular dentin. Pt-3 demonstrated a flat dentinoenamel junction and Pt-2 had an enlarged pulp, barely detectable cementum layer, and ill-defined cemento-dentinal junction. Reduced microhardnesses in enamel, dentin, and both layers were observed in Pt-3, Pt-4, and Pt-1, respectively. Pt-1 showed reduced Ca/P ratio in dentin, while both enamel and dentin of Pt-2 and Pt-3 showed reduced Ca/P ratio. Each SD has distinctive dental characteristics with changes in surface roughness, ultrastructure, and mineral composition of dental hard tissues. In this era of precision dentistry, identifying the specific potential dental problems for each patient with SD would help personalize dental management guidelines.

A Review on Imaging Techniques and Artificial Intelligence Models for Osteoporosis Prediction.

Osteoporosis causes harmful influences on both men and women of all races. Bone mass, also referred to as "bone density," is frequently used to assess the health of bone. Humans frequently experience bone fractures as a result of trauma, accidents, metabolic bone diseases, and disorders of bone strength, which are typically led by changes in mineral composition and result in conditions like osteoporosis, osteoarthritis, osteopenia, etc. Artificial intelligence holds a lot of promise for the healthcare system. Data collection and preprocessing seem to be more essential for analysis, so bone images from different modalities, such as X-ray, Computed Tomography (CT), and Magnetic Resonance Imaging (MRI), are taken into consideration that help to recognize, classify, and evaluate the patterns in clinical images. This research presents a comprehensive overview of the performance of various image processing techniques and deep learning approaches used to predict osteoporosis through image segmentation, classification, and fault detection. This survey outlined the proposed domain-based deep learning model for image classification in addition to the initial findings. The outcome identifies the flaws in the existing literature's methodology and lays the way for future work in the deep learning-based image analysis model.

Physicochemical effect on soil in sliding zone of reservoir landslides

The fate of reservoir landslides is mainly dictated by the mechanical behavior of soil in the sliding zone. This soil may be altered under changing environmental conditions of both physical and chemical nature. In this paper, we present a laboratory study on the changing soil properties under complex physicochemical interactions. The soil specimens are subjected to 1, 2, 3, 5, 7, and 10 wetting-drying cycles. The soil strength is determined by triaxial tests. These tests are performed with three types of pore water, namely, acidic groundwater (AGW), normal groundwater (NGW), and distilled water (DW). The deterioration of soil strength, the change in soil microstructure and mineral composition are observed and correlated. Interesting findings for reservoir landslides are drawn: acidic underground water considerably damages the soil microstructure and deteriorates the shear strength compared to normal underground water, while distilled water causes minimal disaggregation. A three-stage micromechanism associated with four physicochemical interactions is revealed, providing insights into microstructure damage and mineral transformation.