Search Results (37,013)

Due to the impact of disordered mining activities in previous years, numerous abandoned roadways exist in the second mining district of the 13# coal seam in Chejiazhuang Coal Mine. The stability of the new roadway roof was analyzed under various distributions of abandoned roadways above. It was determined that the ultimate stable thickness of the coal layer between the new and abandoned roadways is 4.0 m. When the thickness between the two is less than 4.0 m, the roof becomes unstable after excavation, posing a risk of collapse. Advanced grouting reinforcement is required to enhance roof stability before installing U-shaped steel arches. Mechanical experiments were conducted on the polymer grouting consolidation of fractured coal, showing a significant increase in residual strength compared to intact coal. Furthermore, the uniaxial compressive strength of the polymer grouting consolidation partially recovered. On average, the consolidation coefficient and recovery coefficient were 5.28 and 85.51%, respectively. Grouting increased the ductility of the fractured surrounding rock, enhancing its resistance to deformation and plasticity. A polymer grouting consolidation technology for supporting fractured surrounding rock under the unstable roof of abandoned roadways is proposed, along with the design of corresponding support schemes and parameters. Monitoring the results of mine pressure indicated that the surrounding rock remained stable after roadway excavation, validating the effectiveness of the support schemes and parameters. Full article

In this paper, the application of NiO nanosheets (NiO NSs) for the detection of methotrexate (MTX) is described. The NiO NSs were synthesized using a hydrothermal method. The electrocatalytic activity of two modifiers, ionic liquid (IL) and NiO NSs, was examined on a carbon paste electrode (CPE) in relation to MTX, utilizing voltammetry methods such as cyclic voltammetry (CV), linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), and chronoamperometry at 0.1 M phosphate buffer solution (PBS) pH = 7.0. The anodic peak currents for MTX on the NiO NSs/IL/CPE were approximately 3.5 times greater than those on unmodified CPE. Based on DPV measurements, the electrochemical sensor demonstrated a linear response in the concentration range (LDR: 0.01 µM to 160.0 µM), with a limit of detection (LOD: 0.003 µM). Moreover, the NiO NSs/IL/CPE sensor demonstrated good stability, repeatability, reproducibility, and selectivity, which were of importance in the electroanalysis of compounds. Lastly, the practicality of the NiO NSs/IL/CPE sensor was assessed by analyzing MTX levels in urine samples and pharmaceutical formulation, yielding satisfactory recovery rates of 97.1% to 103.3%. Full article

In view of the deep burial depth, high formation pressure, and presence of top and bottom water in offshore extra-heavy-oil reservoirs, this paper conducts a study on the production performance and flow field variation law of steam huff-and-puff to steam flooding conversion in thick heavy-oil reservoirs based on physical simulation, and analyzes the development effect of the conversion from steam huff-and-puff to steam flooding. On this basis, by comprehensively considering the advantages of gravity-assisted steam flooding and a three-dimensional HHSD well pattern obtained from physical simulation experiments, this paper proposes a well pattern development mode of steam huff-and-puff to composite displacement and drainage, and analyzes the development effect of this well pattern mode using the reservoir numerical simulation method. The research results show that, compared with the planar well pattern of steam huff-and-puff to steam flooding conversion, the adoption of the three-dimensional well pattern can significantly improve the degree of reservoir production and the expansion dynamics of the steam chamber, and mitigate adverse effects such as the increase in water cut caused by top and bottom water on thermal recovery. The composite development of steam huff-and-puff to composite displacement and drainage can be divided into three stages: thermal communication, gravity drainage-assisted steam flooding, and thermal breakthrough erosion and oil washing. The steam chamber presents a development mode of “single-point development–rapid longitudinal expansion–rapid transverse expansion upon reaching the top–polymerization into a sheet”, and simultaneously possesses the oil displacement mechanisms of both steam displacement and gravity drainage. The proposed composite mode of steam huff-and-puff to composite displacement and drainage has guided the implementation of adjustment wells in the Bohai L Oilfield, and the recovery factor has been increased by about 20% compared with the steam huff-and-puff development of the basic well pattern. This study has reference and guiding significance for the efficient thermal recovery development of this oilfield. Full article

One of the most challenging aspects of manipulating the flow of fluids in subsurfaces is to control their flow direction and flow behavior. This can be especially challenging for compressible fluids, such as CO₂, and for multiphase flow, including both water and carbon dioxide (CO₂). This research studies the ability of two crosslinked polymers, including hydrolyzed polyacrylamide and acrylic acid/hydrolyzed polyacrylamide crosslinked polymers, to reduce the permeability of both CO₂ and formation water using different salinities and permeability values and in the presence of crude oil under different injection rates. The result showed that both polymers managed to reduce the permeability of water effectively; however, their CO₂ permeability-reduction potential was much lower, with the CO₂ permeability reduction being less than 50% of the water reduction potential in the majority of the experiments. This was mainly due to the high flow rate of the CO₂ compared to the water, which resulted in significant shearing of the crosslinked polymer. The crosslinked polymers’ swelling ratios were impacted differently based on the salinity, with the maximum swelling ratio being 9.8. The HPAM polymer was negatively affected by the presence of crude oil, whereas increasing salinity improved its performance greatly. All in all, both polymers had a higher permeability reduction for the formation water compared to CO₂ under all conditions. This research can help improve the applicability of CO₂-enhanced oil recovery and CO₂ storage in depleted oil reservoirs. The ability of the crosslinked polymers to improve CO₂ storage will be a main focus of future research. Full article

With the changing picture of global energy supplies and the shift toward the energy transition, it has never been more important to look for alternative sources of energy. Globally there are tens of thousands of abandoned oil fields with considerable reserves left behind. These have the potential to be reactivated to become an energy supply that is cleaner than conventional oil and gas. This can be achieved by the use of in situ combustion and the subsequent exploitation of the inherent increase in temperature and pressure to produce geothermal energy, allied to sequestration of the mixture of produced fluids. In situ combustion (ISC) has conventionally been used as an enhanced oil recovery technique, with a high failure rate that has been recently attributed to poor reservoir selection and project design. We suggest that the failure of many earlier ISC projects is due to insufficient appreciation of how the subsurface geology affects the process. With the use of computer numerical modelling, we aim to ascertain how the geometry and heterogeneity of the reservoir control the success of the process. Here we employ simple three-dimensional sector models to assess a variety of different petrophysical heterogeneities, within a set of different reservoir geometries, on the temperature, velocity, propagation stability and enthalpy rate. These models illustrate that the biggest impact on success of the ISC process for geothermal energy generation, as a function of temperature and enthalpy, is the location of the wells relative to the heterogeneities and the scale of heterogeneities. Metre-scale heterogeneities do not have a significant effect on this. Instead, the biggest contributor to the propagation stability and direction of the fire front is the presence of a large-scale (10 s to 100 s of metres) heterogeneities, such as channels, or the geometry of a tilted fault block; both have a strong control over the direction of the propagation, and therefore are important factors with regards to well placement. Full article

During the COVID-19 pandemic, many countries implemented widespread restrictions in an effort to mitigate the spread of the virus. These measures had various impacts on the wellbeing of residents. This study explores the effects of the pandemic on wellbeing across different segments of the population in Israel, a country that rapidly administered vaccines and eased restrictions. Two online surveys were conducted on a representative sample of the population, one during the peak of the crisis and another 15 months later during the tail end. The analysis, conducted using multivariate statistical methods, revealed that the negative effects on wellbeing observed during the height of the crisis had largely diminished over time. The significant lifestyle changes prompted by the pandemic and governmental responses had mostly short-lived consequences on wellbeing. Yet, social connections continued to exhibit the strongest association with mitigating subjective wellbeing impacts. Additionally, this study found that the gap in wellbeing between disadvantaged and privileged groups widened as the crisis subsided, suggesting that some disasters may have an initial equalizing effect that wears off with time. The results emphasize the importance of considering the wellbeing impacts when implementing public health policies and providing ongoing support, particularly for disadvantaged populations, throughout the recovery period. Full article

Forward osmosis (FO) technology, known for its minimal energy requirements, excellent resistance to fouling, and significant commercial potential, shows enormous promise in the development of sustainable technologies, especially with regard to seawater desalination and wastewater. In this study, we improved the performance of the FO membrane in terms of its mechanical strength and hydrophilic properties. Generally, the water flux (J_w) of polyisophenylbenzamide (PMIA) thin-film composite (TFC)-FO membranes is still inadequate for industrial applications. Here, hydrophilic polydopamine (PDA)@ zeolitic imidazolate frameworks-8 (ZIF-8) nanomaterials and their integration into PMIA membranes using the interfacial polymerization (IP) method were investigated. The impact of PDA@ZIF-8 on membrane performance in both pressure-retarded osmosis (PRO) and forward osmosis (FO) modes was analyzed. The durability and fouling resistance of these membranes were evaluated over the long term. When the amount of ZIF-8@PDA incorporated in the membrane reached 0.05 wt% in the aqueous phase in the IP reaction, the J_w values for the PRO mode and FO mode were 12.09 LMH and 11.10 LMH, respectively. The reverse salt flux (J_s)/J_w values for both modes decreased from 0.75 and 0.80 to 0.33 and 0.35, respectively. At the same time, the PRO and FO modes’ properties were stable in a 15 h test. The incorporation of PDA@ZIF-8 facilitated the formation of water channels within the nanoparticle pores. Furthermore, the J_s/J_w ratio decreased significantly, and the FO membranes containing PDA@ZIF-8 exhibited high flux recovery rates and superior resistance to membrane fouling. Therefore, PDA@ZIF-8-modified FO membranes have the potential for use in industrial applications in seawater desalination. Full article

Contemporary therapeutic trauma practice privileges symptom-based models that overlook the potential of materiality and space in trauma healing. The responsibility for recovery is situated in the individual (i.e., the parent). We suggest that trauma and lived experiencing produce and are produced by the complex relational entanglings of parent, infant, and the dyad with the world. Employing a new materialist orientation to perinatal and infant mental health and trauma, we propose multimodal mapping as an approach that can move with the multisensorial, multidimensional rhythms of trauma and trauma healing as they unfold in a series of now moments; moments that emerge within the context of the parent–infant relationship. This article re-presents the conceptual material and multimodal maps that emerged from our presentation and experiential invitation at the Big Trauma, Big Change Forum, 2024. Organised into two interconnected parts, we begin by emphasising the capacity of multimodal mapping to enable a nuanced translation of lived experiencing for parents and infants, in research and practice, that can transform trauma and potentiate healing. The second part brings focus to a new mapping experiment whereby the audience engaged in a multimodal process of re-configuring the lived experiencing of parent–infant night-time spaces using collage, images, and group process. We include three illustrations of night-time spaces common to parents and infants, exploring the power of materiality, the arts, and objects in transforming the affective, sensory, and embodied affordances that shape mental health. Arts-based mapping interventions can profoundly shape how we understand and respond to trauma, moving us towards a “more-than” conceptualisation of lived experiencing that is sensed and animated in everyday and every “thing” moments. Our hope is to inspire the audience in adopting a relational orientation that innovates new processes of discovery by mapping the human and more-than-human elements involved in parent–infant well-being and the unravelling of trauma. Full article

Neonatal brain injury remains a significant issue with limited treatment options. This study investigates the potential of the endogenous neurosteroid dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) as neuroprotective agents, building on evidence of their mechanisms in adult brain injury models. The primary objective was to evaluate their neuroprotective and anti-oxidative properties in a mouse model of neonatal hypoxic–ischemic brain injury. Using the modified Rice–Vannucci model, brain injury was induced in 7-day-old mouse pups, followed by treatment with various concentrations of DHEA and DHEAS (0.1, 1, and 10 µg/g body weight) via intraperitoneal injection after a 2 h recovery period. Mice were sacrificed after 24 hours for analysis of somatometry, brain injury, apoptosis, microglial activation, and oxidative stress markers (NOX2, 4-HNE, 8-OHdG), along with the anti-oxidant marker SOD1. While no statistically significant effects of DHEA or DHEAS were observed at the tested doses and time points, the absence of toxic or adverse effects highlights their safety profile. These findings provide a foundation for further research into optimizing dosing strategies, timing, and delivery methods. Future studies should refine these variables to maximize neuroprotective efficacy, investigate DHEA(S)’ exact mechanisms of action, and explore their potential for clinical application in neonatal care. Full article

Graphene oxide (GO) and reduced graphene oxide (rGO) have emerged as robust materials in the development of SAs for erbium-doped fiber lasers (EDFLs). Their exceptional optical properties, such as broadband absorption and fast recovery times, make them ideal candidates for achieving ultrashort pulse operation in EDFLs. With its higher oxygen content, GO offers greater nonlinearity and a tunable absorption spectrum, while rGO, yielded through chemical reduction, exhibits enhanced electrical conductivity and higher saturable absorption. These properties facilitate the generation of ultrashort pulses in EDFLs, which are highly desired for various medical imaging, telecommunications, and material processing applications. This review paper comprehensively analyzes the advancements in GO and rGO SAs in the context of EDFLs for mode-locking and Q-switching applications. The performance of EDFLs utilizing GO and rGO SAs is critically evaluated, focusing on key parameters, such as modulation depth, pulse duration, repetition rate, average power, pulse energy, peak power, and signal-to-noise ratio. Additionally, this review delves into the various synthesis methods of GO and rGO thin film, highlighting their impact on the optical properties and performance of SAs. The discussion on techniques to integrate the SAs into laser cavities includes direct deposition of nanoparticles/thin-film-based SAs, tapered-fiber-based SAs, and D-shaped SAs. Furthermore, the paper explores the challenges encountered during the fabrication of ideal GO and rGO SAs, with issues related to uniformity, stability, and tunability, along with proposed solutions to address these challenges. The insights provided offer valuable guidance for future research aimed at enhancing the performance of EDFLs using GO/rGO SAs. Full article

The widespread reliance on paper-based currency poses significant drawbacks, such as counterfeiting, lack of transparency, and environmental impacts. While Central Bank Digital Currencies (CBDCs) address many of these issues, their dependence on continuous internet connectivity limits their usability in scenarios with poor or no network access. To overcome such limitations, this paper introduces ElasticPay, a novel Peer-to-Peer (P2P) Offline Digital Payment System that leverages advanced hardware security measures realised through Trusted Platform Modules (TPMs), Trusted Execution Environments (TEEs), and Secure Elements (SEs). ElasticPay ensures transaction privacy, unforgeability, and immediate settlement while preventing double spending. Our approach integrates robust recovery mechanisms and provides a scalable solution for diverse environments. Extensive experimentation validates the system’s reliability and practicality, highlighting its potential to advance secure and inclusive CBDC ecosystems. We demonstrate the proposed solution implementation on the iPhone mobilephone because it has an inbuilt Secure Enclave, which is an integrated implementation of the necessary TPM, TEE, and SE functionalities. Full article

This study investigated the potential of low-grade gold deposits in modern mining, particularly in the context of declining high-grade resources. The primary method for processing these ores was gravity separation with the Knelson concentrator. A GRG test (gravity recoverable gold test) was conducted on two gold-bearing samples: a polymetallic Cu-Zn-Au ore from Zlaté Hory–Západ (Czech Republic) containing refractory gold and an ore with free gold from Kašperské Hory (Czech Republic). The study evaluated the effectiveness of the GRG test for gold recovery from these ores. The results showed that the Kašperské Hory sample predominantly contained relatively large gold grains, with recovery rates dropping significantly upon finer comminution. In the sample from the Zlaté Hory–Západ deposit, the greatest GRG release occurred in the first and last test stages, suggesting that larger sulfide grains with bound gold passed predominantly in the first stage, while fine gold with residual sulfides passed in the third. Both samples achieved high overall GRG recovery rates, with 64.2% for Kašperské Hory and more than 66% for Zlaté Hory–Západ, demonstrating the efficacy of centrifugal concentrators for both ores. Full article

Plastic pollution is a global problem affecting the environment and, consequently, people’s well-being. Careful and timely end-of-life plastic recycling is certainly a way, albeit a partial one, to remedy the problem. The immediate identification and selection of the different types of plastic materials in the recycling process certainly facilitate its recovery and reuse, allowing the damage caused by plastic emission into the environment to be limited. Recently, new technologies for automatic sorting of plastics based upon fluorescent tagging have been considered. This article reports the synthesis and characterization of fluorescent copolymers of poly(methyl methacrylate) (PMMA) that could be potentially used as fluorescent markers of commercial PMMA. Poly(methylmetacrylate-co-2-(9-carbazolyl)ethyl methacrylate) (P(MMA-co-CEMA)) and poly(methylmetacrylate-co-7-methacryloyloxycoumarin) (P(MMA-co-MAOC)) samples containing a small number of fluorescent units (<4%) were synthesized by free-radical polymerization. All copolymer samples show chemico-physical properties like those of pure PMMA and produce fluorescence emission under 290 nm wavelength excitation. P(MMA-co-CEMA)s and P(MMA-co-MAOC)s were also tested as fluorescent dyes for PMMA identification. The experimental results demonstrate that PMMA/P(MMA-co-CEMA) and PMMA/P(MMA-co-MAOC) blends prepared using 1% by weight of fluorescent copolymer show a homogeneous morphology completely similar to pure PMMA and are still optically active. Full article

The implantation of wind farms in the European territory is being deployed at an accelerated pace. In the proposed framework, the province of La Coruña in the autonomous community of Galicia is tested, with a wide deployment of this type of infrastructure in the territory initiated in the 80s, representing the third autonomous community with the largest exploitation of wind resources, which provides sufficient information, extrapolated to the entire community, to demonstrate the practical usefulness and potential of the method of obtaining the territorial model proposed in this article The regional has been used as the basic administrative subunit of the study variables, considering that the territory thus delimited could have common physical and cultural characteristics. The methodology presented in this article involves the collection and processing of public cartographic data on various factors most repeatedly or agreed upon in the consulted bibliography based on studies by experts in the technical, environmental, and environmental areas, including explanatory variables of risk in a broader context of climate change as the first contribution of this study. Another contribution is the inclusion in the model of the synergistic impact measured as the distance to wind farms in operation (21% of the total area of the sample) to which an area of influence of 4 times the rotor diameter of each of the wind turbines im-planted has been added as a legal and physical restriction. On a solid basis of selection of explanatory variables and with the help of Geographic Information Systems (GIS) and multi-criteria analysis (MCDM), techniques widely documented in the existing literature for the determination of optimal areas for the implementation of this type of infrastructure, a methodological proposal is presented for the development of a strategic, long-term territorial model, for the prioritization of acceptable areas for the implementation of wind farms, including forecasts of increased energy demand due to the effect of climate change and the population dynamics of the study region that may influence energy consumption. This article focuses on the use of multivariate clustering techniques and spatial analysis to identify priority areas for long-term sustainable wind energy projects. With the proposed strategic territorial model, it has been possible to demonstrate that it is not only capable of discriminating between three categories of acceptable areas for the implementation of wind farms, taking into account population and climate change forecasts, but also that it also locates areas that could require conservationist measures to protect new spaces or to recover the soil because they present high levels of risk due to natural or anthropic disasters considered. The results show acceptable areas for wind energy implementation, 23% of the total area of the sample, 3% conservation as ecological spaces to be preserved, and 7% recovery due to high-risk rates. The findings show that coastal regions generally show a more positive carrying capacity, likely due to less dense development or regulatory measures protecting these areas. In contrast, certain inland regions show more negative values, suggesting these areas might be experiencing higher ecological disturbance from construction activities. This information highlights the importance of strategic site analysis to balance energy production with conservation needs. The study provides insights into wind farm deployment that considers the visual and ecological characteristics of the landscape, promoting sustainability and community acceptance. For this reason, these insights can be effectively used for advancing renewable energy infrastructures within the European Union’s energy transition goals, particularly under the climate and energy objectives set for 2030. Full article

The recycling of lithium-ion batteries is increasingly important for both resource recovery and environmental protection. However, the complex composition of cathode and anode materials in these batteries makes the efficient separation of metal mixtures challenging. Hydrometallurgical methods, particularly liquid extraction, provide an effective means of separating metal ions, though they require periodic updates to their extraction systems. This study introduces a hydrophobic deep eutectic solvent composed of trioctylphosphine oxide, di(2-ethylhexyl)phosphoric acid, and menthol, which is effective for separating Ti(IV), Co(II), Mn(II), Ni(II), and Li⁺ ions from hydrochloric acid leachates of NMC (LiNi_xMn_yCo_1−x−yO₂) batteries with LTO (Li₄Ti₅O₁₂) anodes. By optimising the molar composition of the trioctylphosphine oxide/di(2-ethylhexyl)phosphoric acid/menthol mixture to a 4:1:5 ratio, high extraction efficiency was achieved. The solvent demonstrated stability over 10 cycles, and conditions for its regeneration were successfully established. At room temperature, the DES exhibited a density of 0.89 g/mL and a viscosity of 56 mPa·s, which are suitable for laboratory-scale extraction processes. Experimental results from a laboratory setup with mixer-settlers confirmed the efficiency of separating Ti(IV) and Co(II) ions in the context of their extraction kinetics. Full article