Composition Parameters Research Articles

Influence of Gamma-Phase Aluminum Oxide Nanopowder and Polyester-Glass Recyclate Filler on the Destruction Process of Composite Materials Reinforced by Glass Fiber.

Recycling of composite materials is an important global issue due to the wide use of these materials in many industries. Waste management options are being explored. Mechanical recycling is one of the methods that allows obtaining polyester-glass recyclate in powder form as a result of appropriate crushing and grinding of waste. Due to the fact that the properties of composites can be easily modified by adding various types of fillers and nanofillers, this is one of the ways to improve the properties of such complex composite materials. This article presents the strength parameters of composites with the addition of fillers in the form of polyester-glass recyclate and a nanofiller in the form of gamma-phase aluminum nanopowder. To analyze the obtained results, Kolmogorov-Sinai (K-S) metric entropy was used to determine the transition from the elastic to the viscoelastic state in materials without and with the addition of nanoaluminum, during a static tensile test. The tests included samples with the addition of fillers and nanofillers, as well as a base sample without any additives. The article presents the strength parameters obtained from a testing machine during a static tensile test. Additionally, the acoustic emission method was used during the research. Thanks to which, graphs of the effective value of the electrical signal (RMS) were prepared as a function of time, the parameters were previously identified as extremely useful for analyzing the destruction process of composite materials. The values obtained from the K-S metric entropy method and the acoustic emission method were plotted on sample stretching graphs. The influence of the nanofiller and filler on these parameters was also analyzed. The presented results showed that the aluminum nanoadditive did not increase the strength parameters of the composite with recyclate as a result of the addition of aluminum nanofiller; however, its addition influenced the operational parameters, which is reflected in a 5% increase in the UTS value (from 55% to 60%).

Applicability of Global Leadership Initiative on Malnutrition (GLIM) criteria in nutrition risk screening for patients over 60 years old with digestive system tumors – A retrospective study

ObjectiveThis study aimed to identify the most effective nutritional risk screening tool for elderly patients with digestive system tumors. MethodsNutritional risk screening was performed using Nutritional Risk Screening 2002 (NRS2002), prognostic nutritional index (PNI) and Geriatric Nutritional Risk Index (GNRI) for elderly patients who underwent surgical resection of digestive tumor. Comparative analysis of each nutritional screening tool was conducted through Kappa test and ROC curve. ResultsMalnourished individuals diagnosed by the Global Leadership Initiative on Malnutrition (GLIM) criteria had lower levels of hematological parameters (serum albumin, pre-albumin, total protein and hemoglobin) and poorer body composition parameters (body mass index, body fat percentage, edema index, upper arm muscle circumference, skeletal muscle index, and phase angle; P<0.05). NRS2002 demonstrated a sensitivity of 75.56% and specificity of 38.16% under the GLIM criteria, showing moderate agreement (Kappa=0.346, P<0.001). PNI had an average sensitivity of 71.11% and the highest specificity at 87.23%, but exhibited no consistency with GLIM (Kappa=0.152, P=0.062). GNRI showed the highest sensitivity at 91.11% and general specificity at 37.14%, aligning closely with GLIM criteria (Kappa=0.711, P<0.001). GNRI had the highest predictive value (AUC=0.870, 95% CI: 0.801–0.939), followed by NRS2002 (AUC=0.687, 95% CI: 0.589–0.785). Patients diagnosed with malnutrition via GNRI-GLIM exhibited higher rates of surgical site infection (χ2=15.534, P<0.001) and 3-month readmission (χ2=4.499, P=0.034). ConclusionGNRI and NRS2002 demonstrate good performance as GLIM criteria for nutritional screening in elderly patients with digestive tumors, with GNRI being potentially more suitable. Moreover, GNRI-GLIM can predict short-term prognosis in these patients.

The Association between Anthropometric Measurements and Body Composition with Hand Grip Strength among the Elderly Population in Indonesia.

Background/Objectives: Hand grip strength (HGS) is a crucial measure for evaluating muscle function and general physical ability, and it may be associated with several diseases. Previous studies have demonstrated inconsistent associations between anthropometric measurement and body composition with HGS. This study aims to investigate the association between anthropometric measurement and body composition with HGS in the elderly population residing in Indonesia. Methods: This is a cross-sectional study on older adults aged between 60 and 82 years who live in the community. Anthropometric parameters assessed in this study comprised the body mass index (BMI), mid-upper arm circumference (MUAC), calf circumference (CC), and waist circumference (WC). Subsequently, body composition measurements, including fat mass (FM), fat-free mass (FFM), muscle mass (MM), skeletal muscle mass (SMM), and the appendicular skeletal mass index (ASMI), were assessed using a body composition analyzer. Last, the measurement of HGS was conducted using a hand dynamometer. Results: A total of 109 participants were involved in this study. Our study demonstrates a significant association between anthropometric parameters, namely CC and HGS. Subsequently, several body composition parameters, including FFM, SMM, ASMI, and MM in the four extremities, are also significantly associated with HGS. However, in a multivariate analysis, only CC and FFM were able to significantly predict HGS. Conclusions: Improving CC and maintaining FFM may enhance muscle strength in older adults. This suggests that targeted exercise and nutrition programs could increase muscle mass and strength, thereby mitigating age-related decline and improving quality of life.

Development of Pseudo-Homogeneous Three-Dimensional Reaction Anode Structure for Proton Exchange Membrane Water Electrolysis

Solid Polymer Electrolyte (SPE) diaphragm such as Nafion🄬 has been applied to proton exchange membrane water electrolysis (PEMWE) due to the high efficiency and response. The structure of PEMWE consists of a catalyst layer, diffusion layer, current collector, flow-field, etc. In addition to the membrane, these elements and structural parameters were adapted from the proton exchange membrane fuel cell (PEMFC) technology due to the time series factors in the development process and are still strongly influenced by that technology today. Although PEMFC technology is applied to these elements in PEMWE, the material composition, structure, and various parameters are not fully optimized, and the basic structure and technology are diverted from various PEMFC conditions, although the main object of fluid has greatly changed from the gas phase to the liquid phase. As the above background, PEMWE technology needs to go back to the basic level of structural design, mainly from the viewpoint of mass transfer, and reconstruct the component structure.In this study, we focused on the mass transfer characteristics that most affect the performance of PEMWE and investigated a new structure for gas-liquid two-phase fluids for the electrode structure, which is the most important element of PEMWE.Figure 1 shows the two and three-dimensional reaction electrode structures in PEMWE. Figure 1(a) is the electrode structure of a conventional general PEMWE, which is the catalyst reaction in the catalyst layer on the rate-limiting electrode side proceeds in a heterogeneous two-dimensional reaction area. In this current method, sufficient diffusion cannot be maintained from the viewpoint of mass transfer, which leads to performance decrease due to the inability to remove obstacles such as bubbles to mass transport to the catalyst layer. Figure 1 (b) shows the pseudo-homogeneous three-dimensional reaction electrode structure developed in this study. The catalyst is supported on the porous current collector itself. This structure dramatically increases the reaction area from two-dimensional to three-dimensional, and it is expected to greatly improve electrolytic performance by optimizing various parameter conditions.The experimental was performed as following. The anode catalyst IrOx was synthesized from H2IrCl6-nH2O and NaNO3 by the Adams method1). Catalyst Ink, which mixed with the synthesized catalyst and Nafion🄬 dispersion solution, was dropped onto a Ti-web current collector and dried. The anode catalyst loading current collector was evaluated in a 1 cm2 component evaluation electrolyzer2).In this development, the essential issue is the establishment of the conditions to support the catalyst in the three-dimensional reaction area and to maintain the supply path of the proton from the SPE membrane efficiently.References T. Saida, S. Hirano, E. Niwa, F. Sato, and M. Maruyama, ECS Trans., 85, 865 (2018). K. Nagasawa, T. Ishida, H. Kashiwagi, Y. Sano, S. Mitsushima, Int. J. Hydrog. Energy, 46, 36619 (2021). Figure 1

Automated Microstructural Analysis of Anodic Catalyst Layers in Proton Exchange Membrane Water Electrolyzers (PEMWEs) Using Python-Based Image Processing Framework

Adverse climatic conditions caused by greenhouse gas (GHG) emissions from non-renewables have led to increased focus on utilization of clean alternative fuels such as hydrogen (H2). Clean H2 can be obtained via electrochemical reaction of water splitting through proton exchange membrane water electrolyzers (PEMWEs). However, challenges to its widespread commercialization lie with the high H2 production cost, a large portion of which comes from use of expensive anodic catalyst materials. To improve anodic catalyst utilization to attain better performance at reduced cost, a thorough understanding of anodic catalyst layer microstructure is needed. In-depth characterization through scanning transmission electron microscopy with energy dispersive spectroscopy (STEM/EDS) can provide a comprehensive dataset, which can be processed further to extract structural parameters and correlate to electrochemical performance. However, extracting relevant information from these datasets can be very challenging and time-consuming.In this study, an automatic python-based image processing framework is implemented to quantify compositional and microstructural parameters for different IrO2 based catalyst inks and their corresponding catalyst layers. The code can provide areal density of catalyst materials, pore/agglomerate size distribution, connectivity of phases, coverage of catalyst particles by ionomer, and its content percentage and distribution. Quantified parameters are then correlated with the electrochemical performance of the PEMWEs. The results provide adequate pointers to not only help capturing microstructural details of catalyst layers but also provide a basis to predict electrochemical behavior and performance of the inks and catalyst layers being studied.

(Invited) Energy-Efficient and Impurity-Tolerant Electrochemical Co-Generation of Acid and Base Solutions

The sequential application of acid and base solutions can be used to perform chemical transformations that are of interest for carbon management and sustainable resource utilization, including CO2 capture, CO2 removal, production of slaked lime, and recovery of critical minerals. Electrochemical co-generation of acid and base from salt solutions enables their use in closed-loop processes that could be powered by renewable electricity, wherein acid and base are regenerated from the salt byproduct of their application. To be viable at scale, acid-base co-generating systems need to be energy-efficient and tolerant to impurities that are inevitably released into recycle loops. Conventional electrochemical methods for co-generating acid and base, such as bipolar membrane electrodialysis (BPMED), rely on the use of ion exchange membranes (IEMs) to inhibit H+ and OH– recombination, but IEMs cause large resistive losses that severely limit the energy efficiency and current density of these systems. In addition, cation exchange membranes (CEMs) do not tolerate polyvalent cations (e.g., Ca2+, Mg2+) in the presence of base, yet polyvalent cations are intrinsic to all high-impact applications. In this talk, I will describe our development of acid-base co-generating systems in which H+ and OH– recombination is inhibited by competitive transport of supporting electrolyte and H+ masking, which enables the use of a simple porous diaphragm separator instead of IEMs. We developed an ion transport model to predict the current efficiency for acid-base co-generation as a function of the electrolyte composition and operating parameters. Instead of a bipolar membrane, our systems use the H2 oxidation reaction (HOR) and H2 evolution reaction for H+ and OH– generation, respectively. We demonstrate IEM-free production of acid and base at useful concentrations in the presence of polyvalent cations with much higher energy efficiency and current density than state of the art BPMED systems. Individual cells can be stacked by combining HOR and HER electrodes into bipolar gas diffusion electrodes that recirculate H2 with near-unity efficiency. To demonstrate the utility of the acid and base solutions generated by this system, I will describe their use to extract Mg(OH)2 from ultramafic rocks for application in CO2 removal.

Designing high-performance ion-exchangeable glasses with multi-objective optimization and machine learning

Ion exchange typically involves replacing smaller ions with larger ions below the glass transition temperature. This study introduces an innovative computational approach for the inverse design of ion-exchangeable glasses. It aims to simultaneously achieve high depth of layer (DOL) and surface compressive stress (CS), a task complicated by the inherent trade-offs between these properties. Traditional ion exchange experimental methods are not only time-consuming and expensive, but they also involve complex practical difficulties. Addressing these challenges, this paper introduces a novel computational approach that synergistically combines a multi-objective genetic algorithm with machine learning models. The approach involves training models on a diverse set of glass compositions to predict DOL and CS, which then guide an evolutionary algorithm to optimize these properties concurrently. Physics-informed parameters further refine the search, enabling a flexible design framework in glass manufacturing. Comprehensive experimentation and subsequent analysis affirm the proposed method's capacity to efficiently and effectively traverse the intricate design landscape of glass materials. The findings elucidated the influence of distinct compositional and process parameters on DOL and CS, facilitating the manual design process. Additionally, the study identified sixteen glass composition candidates within the SiO2–B2O3–Al2O3–MgO–Na2O system, exhibiting remarkable properties. Specifically, some compositions achieved a DOL of up to 95 μm with a corresponding CS of 890 MPa, while others attained a CS of up to 1654 MPa with a DOL of 14.72 μm.

Fortification of wheat white bread: assessing the suitability of Beta vulgaris trough technological, nutritional, and sensory evaluation

SummaryAs societies undergo shifts in dietary patterns, there is often an increase in nutrition‐related issues. This is particularly evident in the case of wheat bakery products, which have evolved in an unsustainable way. The fortification of wheat flour with vegetables has emerged as a strategy to mitigate the imbalanced composition of white bread. The objective of this study is to address existing knowledge gaps regarding nutritional quality and technological characteristics of food‐to‐food fortified bakery products. A blend of Beta vulgaris powder (up to 5% of the total weight) was incorporated into commercial wheat white flour, and the resulting composition and technological parameters were analysed throughout the bread‐making process, using standard methods (e.g., AAAC, ISO). The sensory assessment of the tested fortified baking products formulations was conducted. The 178 volunteer consumers noted the differences conveyed by B. vulgaris, but scored the taste and colour as acceptable (6 out of 9). Formulations containing moderate amounts of chard (e.g., 2%) were most appreciated. This study demonstrates that B. vulgaris can be employed to enrich white bread, particularly in minerals, such as calcium, magnesium, and iron, in a readily actionable manner that is well accepted by consumers. Furthermore, the use of flour blends contributes to mitigate the impact of fluctuations in wheat availability, thereby enhancing food security.

Effects of swift heavy ions on metal nanoparticles embedded in silica: Using linearly polarized light to monitor the elongation kinetics.

The elongation of metallic nanoparticles (NPs) embedded in a dielectric matrix after irradiation with swift heavy ions is a phenomenon that has been known for several years. However, the precise mechanism behind this deformation process is still not fully understood, primarily due to the dearth of information during intermediate stages of deformation. In this study, we report the continuation of our previous work [Peña-Rodríguez et al., Sci. Rep. 7(1), 922 (2017)], exploiting the strong dependence of the localized surface plasmon resonance on the aspect ratio of elongated metal NPs to study the elongation kinetics in situ. In situ optical absorption spectra were measured using a polarizing beam splitter to separate the longitudinal and transverse plasmon modes of the anisotropic NPs. Then, the detailed geometrical and compositional parameters were determined from a fit of these spectra. The use of linearly polarized light allowed for a more accurate analysis of the elongation kinetics, particularly useful in the first stages, where longitudinal and transverse modes overlap.

Some parameters of hydroponic and soil Rhubarb cultivated in the Ararat Valley of Armenia

Background: Today, the rhubarb plant is selectively included in the diet. Rhubarb juice offers a unique flavor with a surprising range of potential health benefits. Rhubarb is rich in antioxidants, particularly anthocyanins, the pigments responsible for its red hue. These antioxidants are believed to possess anti-inflammatory and anti-bacterial properties, potentially aiding in the fight against various health concerns. Rhubarb juice is an excellent source of vitamins C, and K, crucial for bone health and blood clotting, and also contains vitamin A, contributing to healthy skin and vision. Context and purpose of this study: to investigate for the first time the cultivation of rhubarb (Rheum rhabarbarum) in the Ararat Valley of Armenia in both hydroponic and soil conditions. The research focuses on identifying the optimal growth period to maximize key quality indicators of rhubarb stalks and juice for food and medicinal applications: Brix value, juice density, total titratable acidity, and vitamin C content. Results: Hydroponic cultivation significantly (by three folds) increased the fresh weight of rhubarb petioles (stalks) compared to soil plants. The maximum accumulation of vitamin C in hydroponic plants was observed at the beginning (June) and end (September) of the growing season (19.4 and 17.3 mg%) respectively. However, there was not a significant difference in vitamin C content during July and August (14.3 and 14.0 mg% respectively). Soil plants showed the highest accumulation of vitamin C in September (41.5 mg%), exceeding the values in June by 1.2 times and from July to August by 1.5 times. Total titratable acidity showed seasonal variations: the highest acidity (1.2 to 1.3-fold higher) of hydroponic rhubarb juice was observed in July compared to other months. Soil-grown rhubarb reached peak acidity at the beginning of the growing season (approximately 1.2 times higher than in other months). The Brixo value and juice density peaked in July for hydroponic rhubarb and in August for soil rhubarb. Conclusion: This study highlights the potential of hydroponics for maximizing rhubarb yield and potentially influencing the vitamin C content and acidity profile throughout the growing season in Armenia. The results of further research could be used to optimize nutrient composition and environmental parameters for even greater control over rhubarb quality for food and medicinal purposes. Keywords: Vitamin C, Total titratable acidity, Brixo, Juice density

In Situ-Forming, Bioorthogonally Cross-linked, Nanocluster-Reinforced Hydrogel for the Regeneration of Corneal Defects.

Corneal defects can lead to stromal scarring and vision loss, which is currently only treatable with a cadaveric corneal transplant. Although in situ-forming hydrogels have been shown to foster regeneration of the cornea in the setting of stromal defects, the cross-linking, biomechanical, and compositional parameters that optimize healing have not yet been established. This, Corneal defects are also almost universally inflamed, and their rapid closure without fibrosis are critical to preserving vision. Here, an in situ forming, bioorthogonally cross-linked, nanocluster (NC)-reinforced collagen and hyaluronic acid hydrogel (NCColHA hydrogel) with enhanced structural integrity and both pro-regenerative and anti-inflammatory effects was developed and tested within a corneal defect model in vivo. The NCs serve as bioorthogonal nanocross-linkers, providing higher cross-linking density than polymer-based alternatives. The NCs also serve as delivery vehicles for prednisolone (PRD) and the hepatocyte growth factor (HGF). NCColHA hydrogels rapidly gel within a few minutes upon administration and exhibit robust rheological properties, excellent transparency, and negligible swelling/deswelling behavior. The hydrogel's biocompatibility and capacity to support cell growth were assessed using primary human corneal epithelial cells. Re-epithelialization on the NCColHA hydrogel was clearly observed in rabbit eyes, both ex vivo and in vivo, with expression of normal epithelial biomarkers, including CD44, CK12, CK14, α-SMA, Tuj-1, and ZO-1, and stratified, multilayered morphology. The applied hydrogel maintained its structural integrity for at least 14 days and remodeled into a transparent stroma by 56 days.

Development of a Graded Early Warning Index System and Identification of Critical Temperatures for Coal Spontaneous Combustion Using Composite Gas Characteristics.

Conventional single gas alarm method and coal spontaneous combustion three-stage alarm method have become increasingly inadequate to meet complex underground conditions. To address this issue, this study focuses on the coal in the goaf of the Z109 working face in the Donggucheng Mine as the research object. Through program-controlled heating experiments, the production of carbon monoxide and hydrocarbon gases during the coal oxidation process was determined, and the variation characteristics of gas ratios with temperature were further analyzed. The coal spontaneous combustion process was subdivided into seven small stages, and a quantitative composite parameter coal spontaneous combustion grading warning system was formulated. Based on its characteristics, measures to be taken under different warning levels were proposed, and it was determined that 120, 140, and 160 °C are the key temperatures for coal spontaneous combustion prevention and control in the Z109 working face of Donggucheng Mine. By using numerical simulation, the optimal nitrogen injection position for the working face was determined and the on-site fire prevention and extinguishing measures were optimized, providing insights into the establishment of a coal mine spontaneous combustion warning system.

Effective elastic behavior analysis of three-layer quasicrystal composite plates

In this paper, the effective elastic behavior of three-layer quasicrystal composite plates are forecasted. Firstly, effective properties of the first and third layers quasicrystal composite plates containing ellipsoidal inclusions are obtained according to the Mori-Tanaka model. Secondly, the three-layer composite plates effective behavior parameters are computed by employing the general matrix approach. The numerical examples reveal the influence of the inclusions geometry and volume fraction on the three-layer quasicrystal composite plates effective behavior parameters. The findings indicate that changing the elastic constants of the phason field and phonon-phason coupling field of inclusions will affect the effective behavior parameters of the three-layer quasicrystal composite plates. The increase in layers to some extent reduces the effective behavioral parameters.

Compositional Rheology: Drafting Musical Flux through Fluid Mechanics and Drawing

Abstract This article explores the fluctuating relationship between the concepts of the “smooth” and “striated” musical space and time introduced by French composer Pierre Boulez and further developed by philosopher Gilles Deleuze, as well as its connection to rheology. The study focuses on how the understanding of the Reynolds number (Re), a parameter that characterizes the way a fluid flows in a duct, might provide a new approach to investigating the aforementioned musical concepts and visualizing them through drawing. This article also introduces a way of studying and visualizing musical compositions by establishing analogies between compositional parameters and the molecular and inertial forces that exist within the stream of a fluid.

Химический состав и качественные показатели говядины бычков мясных пород

Purpose. To study the effect of the genotype of bulls on the chemical composition and commodity-technological parameters of beef. Materials and Methods. The object of research is 18–month-old crossbred bulls, obtained as a result of industrial crossing of Kazakh white-headed cattle bulls with heifers of Kalmyk breed (group I), Kazakh white-headed bulls with heifers of Hereford breed (group II) and Kazakh white-headed bulls with heifers of Aberdeen-Angus breed (group III). Purebred bulls of the Kazakh white-headed breed were used as a control group. The slaughter qualities of the experimental animals were determined by control slaughter of three bulls from each group. Chemical analysis of beef samples was carried out according to the following methods and GOST standards: moisture content was determined by drying the sample to a constant mass at a temperature of 100-105°C according to GOST 9793-2016; protein content – by the amount of protein nitrogen by the Kjeldahl method according to GOST 25011-2017; fat content – according to GOST 23042-2015; ash content – according to GOST 31727-2012; amino acid composition was determined according to the method of measuring the mass fraction of amino acids by the CE method on the Kapel-105M system, the concentration of hydrogen ions (pH) was determined according to GOST R 51478-99. Results. It was found that the highest slaughter qualities were possessed by crossbred bulls of the III experimental group. The highest dry matter content was in the average sample of meat of bulls of the III experimental group – 35.13%, which is 0.63% more than in the control; the difference in fat content was 0.23% in favor of the control group. In terms of protein content, the largest amount was recorded in the meat of bulls of the III experimental group – 20.07%, which is higher than in the samples of the control, I and II experimental groups, respectively, by 0.60, 0.84 and 0.77%. The protein-quality index in the samples ranged from 6.30 to 6.48. The pH value of the meat varied slightly – from 5.60 to 5.77. Conclusion. The conducted research has allowed us to establish that the industrial crossing of the Kazakh white-headed cattle with different meat breeds contributes to an increase in productivity, quality indicators, and the beef produced. This is explained by good compatibility of crossed breeds and high breed qualities of studied breeds.

Epicardial adipose tissue volume highly correlates with left ventricular diastolic dysfunction in endogenous Cushing’s syndrome

Background Cushing’s syndrome (CS) is associated with increased risk for heart failure, which often initially manifests as left ventricular diastolic dysfunction (LVDD). In this study, we aimed to explore the potential risk factors of LVDD in CS by incorporating body composition parameters. Methods A retrospective study was conducted on patients diagnosed with endogenous CS no less than 18 years old. The control group consisted of healthy individuals who were matched to CS patients in terms of gender, age, and BMI. LIFEx software (version 7.3) was applied to measure epicardial adipose tissue volume (EATV) on non-contrast chest CT, as well as abdominal adipose tissue and skeletal muscle mass at the first lumbar vertebral level. Echocardiography was used to evaluate left ventricular (LV) diastolic function. Body compositions and clinical data were examined in relation to early LVDD. Results A total of 86 CS patients and 86 healthy controls were enrolled. EATV was significantly higher in CS patients compared to control subjects (150.33 cm3 [125.67, 189.41] vs 90.55 cm3 [66.80, 119.84], p < 0.001). CS patients had noticeably increased visceral fat but decreased skeletal muscle in comparison to their healthy counterparts. Higher prevalence of LVDD was found in CS patients based on LV diastolic function evaluated by E/A ratio (p < 0.001). EATV was proved to be an independent risk factor for LVDD in CS patients (OR = 1.015, 95%CI 1.003–1.026, p = 0.011). If the cut-point of EATV was set as 139.252 cm3 in CS patients, the diagnostic sensitivity and specificity of LVDD were 84.00% and 55.60%, respectively. Conclusion CS was associated with marked accumulation of EAT and visceral fat, reduced skeletal muscle mass, and increased prevalence of LVDD. EATV was an independent risk factor for LVDD, suggesting the potential role of EAT in the development of LVDD in CS.

Molecular Composition of Humic Acids and Soil Organic Matter Stabilization Rate of the First Arctic Carbon Measurement Supersite “Seven Larches”

In the framework of the implementation of the all-Russian climatic project “Carbon measurement test sites”, reference soils of “Seven Larches” carbon supersite, which is a benchmark and the only monitoring site in the Artistic latitudes, were investigated. The morphological structure of representative soils was specified, and it was found that soils are classified as Cryosols of different types (Histic, Stagnic or Gleyic). The basic physico-chemical characteristics of the soils were studied. By means of elemental analysis and 13C NMR spectroscopy, the composition and molecular structure of humic acids from organic and mineral soil horizons were studied. The surface (organic) soil horizons are characterized by high values of H:C molar ratios (1.2–1.3), which indicates a lower degree of the molecular structure aromaticity of humic acids from organic soil horizons. Analysis of the molecular structure of humic acids by 13C NMR spectroscopy showed that humic acids of the studied soils are characterized by the predominance of non-substituted aliphatic (0–47 ppm) and aromatic (108–164 ppm) fragments. Mineral soil horizons are characterized by higher stabilization of organic matter (with lower SOC content—0.5–0.9%) and higher hydrophobicity of humic acid molecules. Comparison of the obtained results with previously published data on the structural and elemental composition of humic acids isolated from soils of similar genesis and geographical location did not reveal any significant differences between the data obtained by us and previously published data. Thus, for “Seven Larches” carbon supersite “reference” parameters of elemental composition of humic acids, their molecular composition and degree of stabilization of soil organic matter were identified.

Gold in sulfide fluids revisited

Gold solubility was measured at temperatures of 350, 400, 450, and 490 °C and pressures of 500 and 1000 bar in an ’oxidized sulfide’ system, as a function of pHT (2 – 10) and sulfur concentration (m(Stotal) = 0.03 – 1.2 [mol·(kg H2O)-1]). In this system, sulfur primarily exists as H2S, H2SO3, H2SO4, their dissociation products, and radical species such as S2- and S3-. The complexes Au(HS)2-, Au2S22-, AuHS(aq), AuHS(H2S)3(aq), and AuOH(aq) were identified as the primary gold species in the experimental fluids, varying with pH and m(Stotal). The solubility constants for Au(HS)2-, a critical (hydro)sulfide complex, align excellently with literature for ’reduced sulfide’ fluids, where sulfur predominantly exists in the 2- oxidation state. New experimental data from the ’oxidized sulfide’ system were regressed along with reliable literature data from ’reduced sulfide’ systems to calculate standard thermodynamic properties and parameters of the Helgeson-Kirkham-Flowers (HKF) model. The solubility constants for charged complexes, Au(HS)2- and Au2S22-, increase sharply with temperature, whereas those for neutral species, AuHS(aq) and AuHS(H2S)3(aq), show a pronounced peak near 300 °C. These (hydro)sulfide complexes account for gold solubility ranging from a few tens of ppb to a few tens of ppm in natural sulfide fluids, depending on the fluid pH. Thermodynamic calculations also indicate that, in addition to (hydro)sulfide species and the hydroxide complex, AuCl2- significantly contributes to Au mobility in high-temperature acidic chloride fluids. Based on new experimental data and prior studies using solubility and X-ray absorption spectroscopy methods, other gold complexes including mixed Au-HS-Cl, Au-HS-S3- species, and complexes with alkali metal cations, are deemed redundant. Above 250 °C, the influence of chloride salts on gold solubility can be accurately modeled using a simple extended Debye-Hückel equation with the term bγ·I = 0. The Setchenov coefficient bn = 0 suffices for calculating the activity coefficients of neutral species. This streamlined thermodynamic model aligns closely with earlier experimental work by Terry Seward and his team, effectively describing the state of Au in all types of natural fluids where Au exists in the 1+ oxidation state, under any set of P-T-f(O2)-f(S2)-compositional parameters.

Experimental investigation on the anti-detonation performance of composite structure containing foam geopolymer backfill material

The compression and energy absorption properties of foam geopolymers increase stress wave attenuation under explosion impacts, reducing the vibration effect on the structure. Explosion tests were conducted using several composite structure models, including a concrete lining structure (CLS) without foam geopolymer and six foam geopolymer composite structures (FGCS) with different backfill parameters, to study the dynamic response and wave dissipation mechanisms of FGCS under explosive loading. Pressure, strain, and vibration responses at different locations were synchronously tested. The damage modes and dynamic responses of different models were compared, and how wave elimination and energy absorption efficiencies were affected by foam geopolymer backfill parameters was analyzed. The results showed that the foam geopolymer absorbed and dissipated the impact energy through continuous compressive deformation under high strain rates and dynamic loading, reducing the strain in the liner structure by 52% and increasing the pressure attenuation rate by 28%. Additionally, the foam geopolymer backfill reduced structural vibration and liner deformation, with the FGCS structure showing 35% less displacement and 70% less acceleration compared to the CLS. The FGCS model with thicker, less dense foam geopolymer backfill, having more pores and higher porosity, demonstrated better compression and energy absorption under dynamic impact, increasing stress wave attenuation efficiency. By analyzing the stress wave propagation and the compression characteristics of the porous medium, it was concluded that the stress transfer ratio of FGCS-ρ-579 was 77% lower than that of CLS, and the transmitted wave energy was 90% lower. The results of this study provide a scientific basis for optimizing underground composite structure interlayer parameters.

Assessment of body compositions in the prediction of metabolic syndrome in adults.

The musculoskeletal system participates in the pathology of metabolic disorders. Several studies have focused on body composition changes; however, the adipose tissue between muscle bundles with different metabolic statuses has rarely been studied. This study sought to explore the association between body compositions and metabolic disorders in Asians, and identify whether these body compositions can be used to detect metabolic disorders with different waist circumferences (WCs) by computed tomography (CT). A total of 116 subjects were included in the study and categorized into the following four groups according to WC and metabolic syndrome (MS): (I) the healthy control group; (II) the normal WC with metabolic disorder group; (III) the normal WC with MS group; and (IV) the larger WC with MS group. The International Diabetes Federation (IDF) criteria based on WC, laboratory tests, body mass index (BMI), and medical history was used to diagnose MS. Body composition parameters, such as muscle attenuation, the cross-sectional area of subcutaneous adipose tissue (SAT), muscle, extramyocellular lipid (EMCL), visceral adipose tissue (VAT), and the ratios between different compositions [e.g., the SMR (SAT/muscle), EMR (EMCL/muscle), and VMR (VAT/muscle)] were calculated for the thigh and abdomen. The areas under the curve (AUCs) of the receiver operating characteristic (ROC) curves adjusted for multiple comparisons were used to discriminate among metabolic disorders. The groups with metabolic disorders had more SAT (P=0.001) and EMCL (P=0.040) in the thigh, and more VAT (P=0.001) and a higher SMR (P<0.001) in the abdomen. EMCL and muscle attenuation in the thigh (AUCs =0.790 and 0.791), and the VMR and SMR in the abdomen were better able to diagnose metabolic disorders (AUCs =0.752 and 0.746) than other body composition parameters. While SAT and EMCL in the thigh (AUCs =0.768 and 0.760), and VAT and the VMR in the abdomen (AUCs =0.788 and 0.775) were better able to diagnose MS than other parameters. Body composition parameters for the thigh and abdomen could assist in detecting patients with an increased risk of MS.