Search Results (7,187)

Utah typically experiences 18 days with high fine particulate matter (PM_2.5) levels exceeding the National Ambient Air Quality Standards per year. In August of 2022, Salt Lake City Mayor Erin Mendenhall convened an Indoor Air Quality Summit, during which experts in healthcare, industrial hygiene, and atmospheric science, among others, expressed the need to prioritize indoor air quality interventions more within the state. We conducted a furnace filter exchange pilot project that involved 11 families in Salt Lake City’s Westside. These families completed a survey regarding air quality-related concerns while researchers took air quality measurements—both inside and outside the residence. The goals of this pilot study were to gather data about the participants’ indoor and outdoor air quality perceptions, how frequently they changed their home air filters, and any barriers they experienced. In addition, this study developed a proof of concept demonstrating collecting preliminary indoor and outdoor air quality data and furnace filter deposition information alongside the survey. The survey results were limited by a small sample size (11 participants); however, among those sampled we found that residents are acutely concerned about outdoor air quality but are less worried about indoor air quality. We measured substantially lower indoor PM_2.5 levels compared to ambient air and found a wide range of filter replacement times from those less than a month to over two years. Our research team learned not only about indoor air quality conditions and resident perceptions, but also about the needs of community members including access to filters, health education, and the need to allow more time to build trust between researchers and residents. Full article

The internal architecture of deep-water channels is highly complex. Previous research has primarily emphasized the sedimentary processes governing channel migration, yet the linkage between sediment-source mechanisms and migration patterns—particularly their vertical evolution—remains insufficiently understood. Drawing on 3D seismic data, well logs, and core analyses, this study delineates the channel architecture within the deep-water succession of the Niger Delta Basin. Furthermore, by correlating high-frequency sea-level fluctuations with the formation timing of structural units, we explore how sea-level changes influence the spatial distribution and evolutionary dynamics of submarine fan systems. This study investigated the bottom-up evolution of two channel-lobe systems—the East Channel System (ECS) and West Channel System (WCS) within the stratigraphic succession, identifying two principal channel migration styles: expansive migration and downstream migration. In the ECS, migration was primarily characterized by a combination of downstream and expansive patterns. In contrast, the WCS displayed intermittent downstream migration, accompanied by some irregular migration. Correlation of sea-level variation curves with corresponding core photographs indicates that the ECS developed during a fourth-order sea-level. Its lower lobe and upper channel intervals each correspond to two complete five-stage sea-level cycles. In this system, debris flows and high-density turbidity currents produced stronger lateral erosion and channel migration, giving rise to the expansive migration style. Conversely, the WCS formed during a four-stage sea-level rise, with its lobe and channel sections likewise corresponding to two complete five-stage sea-level cycles. Here, sedimentation dominated by high- and low-density turbidity currents promoted enhanced erosion and migration along the flow direction, resulting in the predominance of downstream migration patterns. The ECS and WCS together constitute a complete three-tiered stratigraphic sequence representing two lobe–channel systems. This configuration deviates to some extent from the conventional understanding of the spatial distribution of debris flows, lobate channels, main channels, and deep-sea mud deposits. Consequently, during intervals of frequent sea-level fluctuation, deep-water sedimentary components within the continental slope region can partially record the signals of fourth- and even fifth-order sea-level variations, facilitated by a stable tectonic framework and favorable sediment preservation conditions. These findings offer valuable insights for reconstructing regional sedimentary processes and interpreting sea-level evolution. Full article

Indoor exposure to polybrominated diphenyl ethers (PBDEs), particularly those bound to fine particulate matter (PM₁, particles < 1 µm), may pose a health concern, especially in light of prolonged indoor occupancy and the capacity of ultrafine particles to reach the lower respiratory tract. This study investigates indoor exposure to PBDEs associated with PM₁ in residential homes in Zagreb, Croatia, across warm and cold seasons. BDE-47 was consistently detected in all samples, while BDE-183 was consistently absent. Elevated concentrations and increased detection frequencies of BDE-99 and BDE-100 were observed during the colder season. Consequently, total PBDE (ΣPBDE) levels in the cold season were approximately 2.5 times higher than in the warm season. Although estimated daily inhalation intakes were below established oral reference doses, the potential for deep pulmonary deposition and systemic distribution underscores the need for further investigation. These findings represent the first reported data on indoor PM₁-associated PBDEs in Europe, emphasizing the impact of seasonal dynamics on inhalation exposure due to variation on indoor contaminant levels. Full article

The biogeochemical cycling of nitrogen (N) in natural waterbodies, ranging from freshwaters to estuaries and seawater, is fundamental to the health of aquatic ecosystems. Anthropogenic pressures (agricultural runoff, atmospheric deposition, and wastewater discharge) have profound effects on these cycles, leading to widespread problems, such as eutrophication, harmful algal blooms, and contamination of drinking water sources. Monitoring of different N-species—ammonium (NH₄⁺), nitrite (NO₂⁻), nitrate (NO₃⁻) ions, dissolved organic nitrogen (DON), and total nitrogen (TN)—is of crucial importance to protect and mitigate environmental harm. Traditional analytical methodologies, while providing accurate laboratory data, are hampered by logistical complexity, high cost, and the inability to capture transient environmental events in near-real time. In response to this demand, miniaturised microfluidic technologies offer the opportunity for rapid, on-site measurements with significantly reduced reagent/sample consumption and the development of portable sensors. Here, we review and critically evaluate the principles, state-of-the-art applications, inherent advantages, and ongoing challenges associated with the use of microfluidic colorimetry for N-species in a variety of environmental waterbodies. We explore adaptations of classical colorimetric chemistry to microfluidic-based formats, examine strategies to mitigate complex matrix interferences, and consider future trajectories with autonomous platforms and smart sensor networks for simultaneous multiplexed N-species determination. Full article

This study investigates the influence of multilayer architecture on the mechanical, corrosion, and tribological properties of Ti/TiN coatings deposited on biomedical Ti-6Al-4V alloy. Nine multilayer configurations were prepared by DC/RF magnetron sputtering using metallic Ti and ceramic TiN targets, with a fixed TiN/Ti ratio of 3:1 and varying total numbers of layers (3, 5, and 7) and deposition times (30, 60, and 120 min). A strict application of the 10% indentation depth rule was implemented to eliminate substrate effects, which revealed significantly higher intrinsic hardness values (540–740 HV) and indentation moduli (124–143 GPa) compared to the substrate (353 HV; 114 GPa). In contrast, conventional higher-load testing underestimated coating performance due to substrate dominance. Among the investigated architectures, the Ti/TiN-7 configuration exhibited the best balance of properties, combining high hardness (~690 HV), modulus (~137 GPa), improved corrosion resistance (Ecorr up to −0.13 V, Icorr reduced by an order of magnitude), and stable abrasive wear behavior. These findings demonstrate that both bilayer number and deposition time critically determine the mechanical and functional response of Ti/TiN multilayers. The results provide practical guidelines for the reliable characterization and design of multilayer coatings for biomedical and aerospace applications. Full article

We report the implementation of replica-averaged molecular dynamics in the UNRES coarse-grained model of polypeptide chains, with application to the restraints determined by nuclear magnetic resonance. The analytical ESCASA algorithm is used to estimate interproton distances from coarse-grained geometry. With synthetic restraints derived from two selected conformations of the L129–L153 loop of the Slr1183 protein from Synechocystis sp. (2KW5), the replica-averaged extension of UNRES retrieved the ensemble of conformations close to the parent structures, with residual content of those not similar to any of them, and comparable populations of both families. Tests with a small putatively multistate protein (PDB: 2LWA) and two proteins with disordered regions (2KW5 and 2KZN, respectively) run in multiplexed temperature replica exchange mode with replica averaging resulted in conformational ensembles that had fewer distance-restraint violations than those deposited in the Protein Data Bank. The ensembles obtained with replica averaging also had fewer distance-restraint violations than those obtained in our previous work, in which time-averaged restraints were implemented. The upgraded UNRES can be used in data-assisted simulations of multistate and intrinsically-disordered proteins and proteins with intrinsically disordered regions. Full article

This article investigates the anticorrosive properties of Zr-ZrN coatings, including Zr-(Zr,Hf)N, Zr-(Zr,Ti)N, Zr,Hf-(Zr,Hf,Nb)N, and Zr,Nb-(Zr,Nb)N, deposited on AISI 321 stainless steel substrates. The hardness and elasticity modulus of these coatings, as well as their scratch test strength, were measured. Corrosion current densities were calculated using the polarisation resistance method and by extrapolating the linear sections of the cathodic and anodic curves under electrode polarisation. The structure and composition of the sample surfaces were analysed by transmission electron microscopy. Notably, the nitride coatings reduced the corrosion current density in a 3% aqueous NaCl solution at 25 °C by more than 10 times, from 6.96 for the uncoated substrate to 0.17 μA/cm² for the Zr-(Zr,Ti)N-coated sample. The addition of Ti nitride to Zr-ZrN led to the most significant decrease in the corrosion current density. However, the introduction of Nb caused an increase in the corrosion rate and a decrease in the polarisation resistance, and Hf did not affect the corrosion-protective properties of the studied nitride coatings. Full article

With continuous breakthroughs in electrochromic technology, tungsten trioxide (WO₃) thin films, as a core material in this field, are rapidly expanding their applications in smart windows, anti-glare automotive rearview mirrors, and adaptive optical lenses. Owing to its excellent electrochromic properties—including high optical modulation, short switching times, and high coloration efficiency—WO₃ has become a research focus in the field of electrochromic devices. This review takes WO₃ thin films as the research subject. It begins by introducing the crystal structure of WO₃ and the ion/electron co-intercalation-based electrochromic mechanism and explains two key performance parameters for evaluating electrochromic properties: optical modulation amplitude and coloration efficiency. Subsequently, it provides a detailed review of recent advances in the preparation of WO₃ thin films via physical methods (including sputtering deposition, evaporative deposition, and pulsed laser deposition) and chemical methods (including hydrothermal, sol–gel, and electrodeposition methods). A systematic comparison is made of the microstructure and electrochromic performance (optical modulation amplitude and coloration efficiency) of films prepared by different methods, and the interaction between WO₃ film morphology and device structure is analyzed. Finally, the advantages and challenges of physical and chemical methods in tuning film properties are summarized, and the outlook of their application prospects in high-performance electrochromic devices is given. This review aims to provide guidance for the selection and process optimization of WO₃ thin films with enhanced performance for applications such as smart windows, anti-glare rearview mirrors, and adaptive optical systems. Full article

The Wushan Loess, situated in the Yangtze Three Gorges region of China, represents the southernmost aeolian loess deposit in China and provides critical insights into Late Pleistocene paleoenvironmental conditions and East Asian monsoon dynamics. Despite its significance, the genesis and provenance of this unique loess deposit remain controversial. This study employs an integrated multi-proxy approach combining detrital zircon U-Pb geochronology, optically stimulated luminescence (OSL) dating, and detailed grain size analysis to systematically investigate the provenance and depositional mechanisms of the Wushan Loess. Three representative loess–paleosol profiles (Gaotang-GT, Badong-BD, and Zigui-ZG) were analyzed, yielding 17 OSL ages, 729 grain size measurements, and approximately 420 analyses per profile were conducted, yielding 1189 valid ages (GT 406, BD 391, ZG 402). OSL chronology constrains the deposition period to 18–103 ka (Marine Isotope Stages 2–5), coinciding with enhanced East Asian winter monsoon activity during the Last Glacial period. Grain size analysis reveals a dominant silt fraction (modal size: 20–25 μm) characteristic of aeolian transport, with coarse silt (20–63 μm) averaging 47.1% and fine silt (<20 μm) averaging 44.2% of the sediments. Detrital zircon U-Pb age spectra exhibit consistent major peaks at 200–220 Ma, 450–500 Ma, 720–780 Ma, and 1800–1850 Ma across all profiles. Kernel Density Estimation (KDE) and Multi-Dimensional Scaling (MDS) analyses indicate a mixed provenance model. Non-negative least squares (NNLS) unmixing confirms this quantitative source apportionment., dominated by proximal contributions from the upper Yangtze River basin (including the Three Gorges area and Sichuan Basin, ~65%–70%), supplemented by distal dust input from the Loess Plateau and northern Chinese deserts (~30%–35%). This study establishes for the first time a proximal-dominated provenance model for the Wushan Loess, providing new evidence for understanding southern Chinese loess formation mechanisms and Late Pleistocene East Asian monsoon evolution. Full article

Liver rhythm has a significant effect on lipid metabolism and immune function in chickens. However, reports on its underlying mechanisms and key genes are relatively scarce. We collected liver samples at seven time points during one light/dark cycle and investigated the candidate genes and pathways related to hepatic rhythm through transcriptomic sequencing. Trend analysis revealed that the expression of genes in Profile 5 exhibited rhythmic fluctuations, and these genes (e.g., FAM21C, SRSF4, and TLR2A) were enriched in immune function and biological rhythm. The genes (e.g., MSMO1, ELOVL2, and HMGCR) in Profile 2 that were related to lipid metabolism also exhibited a rhythmic trend. A total of 845 differentially expressed genes (e.g., MSMO1 and FAM21C) were detected between light/dark conditions. Lipid metabolism and immune functions showed the most changes between the two conditions. Immune-related processes (e.g., autophagy) were more active in the light phase, while in the dark phase, lipid metabolism (e.g., sterol biosynthesis) was more active. Weighted gene coexpression network analysis revealed that the tan (including C1QA, TLR2A, and others) and cyan (including ELOVL2, IARS1, and others) modules were strongly associated with the hepatic circadian rhythm. Cosinor analysis revealed that 9 lipid-related genes (e.g., MSMO1, HMGCR1, and ELOVL2) and 11 immune-related genes (e.g., FAM21C, TLR4, and TLR2A) exhibited significant rhythmic expression. These findings revealed rhythmic changes in hepatic immune and lipid metabolism, providing important insights into the regulation of disease resistance and lipid deposition in chickens. Full article

This work explores solid rocket motor grain design, leveraging additive manufacturing techniques based on slurry deposition and UV-curing. The objective is to develop an automated design procedure to identify optimal solutions that meet mission requirements, exploiting new geometries and ballistic configurations previously unattainable with the classical mix–cast–cure manufacturing process. The design procedure is based on a stochastic optimization approach coupled with surrogate modeling of the pressure–time response, considering variable geometrical and ballistic parameters. Several surrogate models were tested after the creation of suitable databases through the computation of pressure evolution for different configurations. The most appropriate surrogate model was selected and applied within optimization routines to evaluate individual designs. The optimizer identifies the most suitable configuration to obtain the desired pressure–time response and to meet motor requirements. Different design approaches have been tested to evaluate the ballistic distribution’s influence on performance and how it can be leveraged to meet requirements, even with significant modifications in grain geometry. The results show that the proposed procedure is able to effectively achieve the expressed requirements, successfully handling the novel design environment. Furthermore, they highlight the strong influence of the ballistic distribution on performance and show how it can be successfully exploited to guide grain design. Full article

The recovery of rare earth elements (REEs) from the spent NdFeB magnets has great strategic significance for ensuring the security of critical mineral resources. This process requires scientifically designed separation technologies to ensure high output and purity of the obtained rare earths. Hydrometallurgy has been widely applied to extract REEs from spent permanent magnets. This paper summarizes and reviews hydrometallurgical technologies, mechanisms, and applications for the separation and recovery of REEs and iron (Fe) from the spent permanent magnets. Key methods include: The hydrochloric acid total solution method, where the spent NdFeB is completely dissolved in hydrochloric acid, iron is precipitated and removed, and then REEs are extracted. The hydrochloric acid preferential dissolution method, where spent NdFeB magnets are first fully oxidized by oxidative roasting, converting Fe²⁺ to Fe³⁺, which hydrolyzes to Fe(OH)₃, and is precipitated and removed, allowing for the subsequent extraction of REEs to obtain rare earth oxides. Acid baking and water leaching, where spent NdFeB is calcined with acidification reagents, and the calcined products are dissolved in water to leach out REEs. At the same time, Fe is retained in the leaching residue. Electrolysis in aqueous solution, where Fe is electrolyzed at the anode or deposited at the cathode to separate it from REES. Organic acids leaching, where organic acids dissolve metals through acidolysis and complexation. Bioleaching, which utilizes microorganisms to recover metal through biological oxidation and complexation. Ionic liquid systems, where Fe or REEs are extracted using ionic liquid or leached by deep eutectic solvents. This paper provides an in-depth discussion on the challenges, advantages, and disadvantages of these strategies for recycling spent NdFeB magnets, as well as the leaching and extraction behavior of REEs. It focuses on environmental impact assessment, improving recovery efficiency, and decreasing reagent consumption. The future development direction for recycling spent NdFeB magnets is proposed, and a research idea of proposing a combined process to avoid the drawbacks of a single recycling method is introduced. Full article

The development of a geomechanical model is aimed at enhancing the safety of mining operations through the determination of optimal slope angles and the probabilistic assessment of pit wall stability. For the conditions of open-pit mining, three-dimensional geomechanical models were constructed based on the calculation of the slope stability factor using the Rocscience Slide2/Slide3 (v.9.027, 2023) software package. The stress–strain state of the rock mass at the final stage of extraction was evaluated using the finite element method. Strength reduction factors (SRF) were determined considering the physico-mechanical properties of the rocks forming the near-contour zone of the massif. The stability of the pit slopes was assessed along individual geological cross-sections in accordance with the design contours of the Northern Katpar open pit. Calculations performed using several methods confirmed the overall stability of the pit walls. The final design parameters of the projected open pit were determined. For the first time, it was established that in the southern and southwestern sectors of the Northern Katpar pit, within the elevation range of +700 to +400 m, a reduction in the SFR (from 1.18 to 1.41) occurs due to the predominance of siltstones and the presence of tectonic disturbances. The generalized results of numerical slope stability analyses for the design pit contour, together with the developed geological–structural model of the deposit, provide a basis for ensuring the safe conduct of mining operations at the site. Full article

It is known that the addition of SrO heterogeneous nucleation site particles can refine the microstructure of SUS316L stainless steel additively manufactured (AMed) by powder bed fusion (PBF). In this study, this idea was confirmed by directed energy deposition (DED). However, there are several types of DED machines, and the energy system and the material supply system of these machines are different depending on each machine. In this study, the grain refinement behavior and the formability of AMed SUS316L stainless steel with the addition of SrO heterogeneous nucleation site particles are evaluated using a single-beam type LAMDA 200 machine and a multi-beam type ALPION Series machine. The size of the melt pool made by the ALPION Series machine is smaller than that of the LAMDA 200 machine, which results in a shorter residence time in the liquid state of the melt pool for the ALPION Series machine. The grains formed in the inoculated sample manufactured by the ALPION Series machine under the unidirectional scanning strategy are found to be refined compared to those in the uninoculated sample. On the other hand, it is found that the formation of defects and the crystallographic texture observed in the samples manufactured by the LAMDA 200 machine is suppressed by the addition of SrO heterogeneous nucleation site particles. These differences between the ALPION Series and LAMDA 200 machines would come from the differences in the melting state, including temperature, cooling conditions, and re-heating. Full article

The seed lots were evaluated based on their viability and vigor, which vary according to their origin and the locations where the seeds were produced. However, differences in vigor can be observed within a single seed lot, resulting from the deposition of photoassimilates. In this context, the hypothesis of this study is that distinct locations on the plant may produce seeds with different physiological quality. Therefore, the objective of this work was to evaluate how pod position influences the vigor of seeds from different soybean genotypes. Field experiments were conducted during the 2021/22 and 2022/23 crop seasons in Brazil. The experimental design was a randomized complete block with four replications and 32 soybean populations from the UFMS/CPCS Breeding Program. During the R4, R5, R6, and R7 reproductive stages of soybean, at the time of pod formation, the plants in each block were tagged with string to delimit the uppermost point at which pods had formed. Tagging was carried out as each stage change was verified, at approximately eight-day intervals. When analyzing how the pod position of the plant influences seed physiological variables, we found that position P1 was responsible for the best results for the variables evaluated, with the exception of genotypes G18 and G28. This result indicates that pods from the first position produce seeds with greater germination capacity and a higher ability to generate normal seedlings. However, the genotypes are still under development and, therefore, do not yet exhibit stability. Nevertheless, the results obtained highlight the relationship between the pod position of the plant and seed physiological variables. The position of the pods on the soybean plant influences the physiological quality of the seeds. In general, the P1 position, when the plants are in the R4 reproductive stage, with fully developed pods measuring 2 cm on one of the four upper nodes of the stem, is responsible for the best results in seed physiological quality tests for most of the soybean genotypes evaluated. These results indicate that pod position should be considered in breeding and seed production programs, since genotypes with greater physiological stability in the upper positions may be preferential in selection strategies. In the future, studies in different environments and evaluation of biochemical traits may confirm these patterns and contribute to the development of cultivars with higher seed quality and physiological uniformity. Full article