Search Results (900)

Salt cavern gas storage (SCGS) is a key development direction for future energy storage. However, the stability of the surrounding rock in underground SCGS remains a challenging issue to be resolved. This study uses numerical simulation methods to analyze the stability of the surrounding rock in SCGS at different height-to-diameter ratios and burial depths during both solution mining and long-term operation. The research results show that: SCGS at the same burial depth, as the height-to-diameter ratio increases from 1.2 to 2.2, the maximum displacement of the surrounding rock decreases by 32.3% and the plastic zone area decreases by 54.1%. However, the density of the plastic zone and the volume shrinkage of SCGS rate increase. The optimal cavern shape lies between a height-to-diameter ratio of 1.2 and 1.5. At the same height-to-diameter ratio, the stability of the salt cavern decreases as burial depth increases: the maximum displacement of the surrounding rock, cavern shrinkage rate, and plastic zone area increase by 94.6%, 99.05%, and 78.61%, respectively. Therefore, within a reasonable burial depth range, a shallower burial depth is more favorable for the stability of the surrounding rock. The presence of interlayers reduces cavern displacement, plastic zone, and cavity volume shrinkage, thereby influencing the stability of the surrounding rock. Among them, the interlayer located at the cavern waist reduced the cavern shrinkage rate by 10% and the maximum displacement by 21.9%, exerting the greatest influence on the stability of the surrounding rock. Full article

Particle accelerators are powerful tools in fundamental research, medicine, and industry that provide high-energy beams that can be used to study matter and to enable advanced applications. The state-of-the-art particle accelerators are fundamentally constructed from superconducting radio-frequency (SRF) cavities, which act as resonant structures for the acceleration of charged particles. The performance of such cavities is governed by inherent superconducting material properties such as the transition temperature, critical fields, penetration depth, and other related parameters and material quality. For the last few decades, bulk niobium has been the preferred material for SRF cavities, enabling accelerating gradients on the order of ~50 MV/m; however, its intrinsic limitations, high cost, and complicated manufacturing have motivated the search for alternative strategies. Among these, sputter-deposited superconducting thin films offer a promising route to address these challenges by reducing costs, improving thermal stability, and providing access to numerous high-T_c superconductors. This review focuses on progress in sputtered superconducting materials for SRF applications, in particular Nb, NbN, NbTiN, Nb₃Sn, Nb₃Al, V₃Si, Mo–Re, and MgB₂. We review how deposition process parameters such as deposition pressure, substrate temperature, substrate bias, duty cycle, and reactive gas flow influence film microstructure, stoichiometry, and superconducting properties, and link these to RF performance. High-energy deposition techniques, such as HiPIMS, have enabled the deposition of dense Nb and nitride films with high transition temperatures and low surface resistance. In contrast, sputtering of Nb₃Sn offers tunable stoichiometry when compared to vapour diffusion. Relatively new material systems, such as Nb₃Al, V₃Si, Mo-Re, and MgB₂, are just a few of the possibilities offered, but challenges with impurity control, interface engineering, and cavity-scale uniformity will remain. We believe that future progress will depend upon energetic sputtering, multilayer architectures, and systematic demonstrations at the cavity scale. Full article

Due to the rising atmospheric carbon dioxide levels driven by human activity, extensive scientific efforts have been dedicated to developing methods aimed at reducing its concentration in the atmosphere. A novel approach involves using hydrates as a long-lasting reservoir of CO₂ sequestration. This review provides an initial overview of hydrate characteristics, their formation mechanisms, and the experimental techniques commonly employed for their characterization, including X-ray, Raman spectroscopy, cryoSEM, DSC, and molecular dynamic simulation. One of the main challenges in CO₂ sequestration via hydrates is the requirement of high pressures and low temperatures to stabilize CO₂ molecules within the hydrate crystalline cavities. However, deviations from classical temperature-pressure phase diagrams observed in natural and engineered environments can be explained by considering that hydrate stability and formation are primarily governed by chemical potentials, not just temperature and pressure. Activity, which reflects concentration and non-ideal interactions, greatly influences chemical potentials, emphasizing the importance of solution composition, salinity, and additives. In this context the role of promoters and inhibitors in facilitating or hindering hydrate formation is discussed. Furthermore, the review presents an overview of the impact of marine sediments and naturally occurring compounds on CO₂ hydrate formation, along with the sampling methodologies used in sediments to determine the composition of these natural compounds. Special attention is given to the effect and chemical characterization of dissolved organic matter (DOM) in marine aquatic environments. The focus is placed on the key roles of various natural occurring molecules, such as amino acids, protein derivatives, and humic substances, along with the analytical techniques employed for their chemical characterization, highlighting their central importance in the CO₂ gas hydrates formation. Full article

In offshore drilling and geological exploration, the stability of jack-up rigs is predominantly determined by the bearing capacities of spudcan foundations during seabed penetration. The penetration depth of spudcans is relatively shallow in hard clay. The formation of a cavity on the top surface of a spudcan often complicates accurate estimation of its capacity. This study employs the finite element method, in conjunction with the Swipe and Probe loading techniques, to examine the failure surfaces of soils of varying strengths. Numerical simulations that consider different gradients of undrained shear strength and cavity depths demonstrate that cavity depth significantly influences the failure envelope. The findings indicate that higher soil strength increases the bearing capacity and reduces the area of soil displacement at failure. Moreover, an enhanced theoretical equation for predicting the vertical-horizontal-moment (V-H-M) failure envelope in hard clay strata is proposed. The equation’s accuracy has been verified against numerical simulation results, revealing an error margin of 3–10% under high vertical loads. This model serves as a practical and valuable tool for assessing the stability of jack-up rigs in hard clay, providing critical insights for engineering design safety and risk assessment. Full article

Bisphenol A (BPA) is classified as an endocrine disruptor that mainly mimics the effects of estrogen and disrupts the synthesis of male androgens. Due to the toxicity of BPA, some new analogs, such as bisphenol BPB, BPC, BPF, PBH, and BPZ, were introduced into the market. The goal of this research was to demonstrate the applicability of kinetic analysis, in particular, Lineweaver-Burk plots, in assessing the impact of bisphenol Z on enzymatic activity. This study aimed to characterize the inhibitory effects of BPZ on 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) activity in the transformation of 11-dehydrocorticosterone (DHC) to corticosterone (CORT). During the determination of the enzymatic reaction product, chromatographic analysis conditions were optimized using gradient elution and an Acquity UPLC BEH C18 chromatographic column. The retention time of the assayed corticosterone was approximately 2 min. Also described and compared were graphical methods of analysis and data interpretation, such as Lineweaver-Burk, Eadie-Hofstee, and Hanes-Woolf plots. The experiments demonstrated that bisphenol Z is a mixed 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) inhibitor, responsible for catalyzing the conversion of 11-dehydrocorticosterone (DHC) to corticosterone (CORT). This relationship was confirmed by analyzing Lineweaver-Burk plots, which showed an increase in apparent K_M with a decrease in the constant V_max, suggesting a mixed inhibition mechanism. Molecular docking and detailed analysis of the interaction profiles revealed that BPZ consistently occupies the active site cavities of all examined enzymes (rat and human 11β-HSD1 and Arabidopsis 11β-HSD2), forming a stabilizing network of non-covalent interactions. Our research has significant biological significance considering the role of the 11β-HSD1 enzyme in the conversion of DHC to CORT and the importance of this process and its functions in adipose tissue, the liver, and the brain. Full article

Effective thermal management of molds is a governing factor of the quality and stability of the injection molding process. This study introduces and validates an integrated cooling layer within a thin-walled insert mold designed to enhance thermal control and cavity filling performance. A coupled heat transfer simulation model was developed and subsequently calibrated against experimental temperature measurements. To isolate the mold’s intrinsic thermal response, temperatures were measured during distinct heating and cooling cycles, free from the perturbations of polymer melt flow. The validated mold was then installed on a Haitian MA1200 III injection molding machine to conduct molding trials under various injection pressures. A strong correlation was found between the simulation and experimental results, particularly as pressure increased, which significantly improved cavity filling and reduced the deviation between the two methods. The integrated cooling layer was shown to enhance heat dissipation, minimize thermal gradients, and promote a more uniform thermal field. This, in turn, improved filling stability, especially at moderate injection pressures. These findings provide robust quantitative data for simulation model calibration and mold design optimization, highlighting the potential of advanced cooling strategies to significantly enhance injection molding performance. Full article

Diabetes has become a global health challenge, driving the demand for innovative, non-invasive diagnostic technologies to improve glucose monitoring. Urinary glucose concentration, a reliable indicator of metabolic changes, provides a practical alternative for frequent monitoring without the discomfort of invasive methods. In this simulation-based study, we propose a novel asymmetric photonic structure that integrates Tamm plasmon polariton (TPP) modes and a cavity mode for high-precision refractive index sensing, with a conceptual focus on the potential detection of urinary glucose. The structure supports three distinct resonance modes, each with unique field localization. Both the TPP modes, confined at the metallic–dielectric interfaces, serve as stable references whose wavelengths are unaffected by refractive-index variations in human urine, whereas the cavity mode exhibits a redshift with increasing refractive index, enabling high responsiveness to analyte changes. The evaluation of sensing performance employs a sensitivity formulation that leverages either TPP mode as a reference and the cavity mode as a probe, thereby achieving dependable measurement and spectral stability. The optimized design achieves a sensitivity of 693 nm·RIU⁻¹ and a maximum figure of merit of 935 RIU⁻¹, indicating high detection resolution and spectral sharpness. The device allows both reflectance and transmittance measurements to ensure enhanced versatility. Moreover, the coupling between TPP and cavity modes demonstrates hybrid resonance, empowering applications such as polarization-sensitive or angle-dependent filtering. The figure of merit is analyzed further, considering resonance wavelength shifts and spectral sharpness, thus manifesting the structure’s robustness. Although this study does not provide experimental data such as calibration curves, recovery rates, or specificity validation, the proposed structure offers a promising conceptual framework for refractive index-based biosensing in human urine. The findings position the structure as a versatile platform for advanced photonic systems, offering precision, tunability, and multifunctionality beyond the demonstrated optical sensing capabilities. Full article

Background/Objectives: Maxillofacial volumetric deficits are often treated using structural fat grafting with autologous free fat grafts. The buccal fat pad (BFP) is commonly used as a pedicled flap for limited oral cavity applications. This study explores its use as a free graft for reconstructing deformities in the upper and lower lips caused by trauma or tumor resections. Methods: Five patients underwent soft tissue defect reconstruction using a free fat graft from the BFP, following standard surgical procedures. Techniques for harvesting, transferring, and evaluating aesthetic and functional outcomes up to three months post-surgery are detailed, with long-term follow-up extending to an average of 20 months (range 12–24 months). Results: Initial post-operative assessments showed lip asymmetry due to edema and excessive graft volume. Partial necrosis was observed within 1–2 weeks, typical of tissue healing. By 4–5 weeks, mucosal revascularization occurred, with desired lip volume and functionality achieved between 8–12 weeks. Long-term follow-up averaging 20 months demonstrated excellent graft stability with no volume regression beyond the vermilion border in all patients. Conclusions: The BFP as a free graft offers advantages such as high survival rates and easy harvesting. It effectively restores lip function, volume, and aesthetics. Challenges include graft manipulation, retention, potential fibrosis, and volume unpredictability. Future refinements in technique and follow-up are necessary to overcome these issues, enhancing the reliability of BFP for lip reconstruction. Full article

As a core component of aero-engines, double-row ball bearings’ lubrication performance directly impacts the operational stability of the aircraft engine. However, existing under-race lubrication designs primarily rely on empirical knowledge, with insufficient understanding of the complex oil–air two-phase flow mechanisms, leading to bottlenecks in optimizing lubrication efficiency. Therefore, based on the computational fluid dynamics (CFD) method, a two-phase flow model for double-row ball bearings was established to systematically analyze the influence patterns of key parameters—including rotational speed, oil supply rate, number of under-race holes, diameter of under-race holes, and oil properties (viscosity, density)—on the distribution of the oil–air two-phase flow. The findings reveal that (1) the oil in the circumferential direction of the bearing cavity exhibits periodic distribution characteristics correlated with the number of under-race holes; (2) the self-rotation effect of balls hinders the migration of oil toward the outer raceway region, resulting in a significant reduction in the oil volume fraction within the bearing cavity; (3) compared with the single-sided oil supply configuration, the double-sided oil supply structure demonstrates superior lubrication performance. These research results provide theoretical support and reference data for the optimal design of under-race lubrication systems for double-row ball bearings. Full article

We report high-resolution, cavity-enhanced direct frequency comb Fourier transform spectroscopy of cold acetylene (C₂H₂) molecules in a planar supersonic jet expansion. The experiment is based on a near-infrared frequency comb with a 300 MHz effective repetition rate, matched to a high-finesse enhancement cavity traversing the jet. The rotational and translational cooling of acetylene was achieved via expansion in argon carrier gas through a slit nozzle. By interleaving successive mode-resolved spectra measured at different comb repetition rates, we retrieved full absorption line profiles. Spectroscopic analysis reveals sharp, Doppler-limited transitions corresponding to a jet core rotational temperature below 7 K. Frequency comb and cavity stabilization were achieved through active Pound–Drever–Hall locking and mechanical vibration damping, enabling a spectral precision better than 2 MHz, limited by the vibrations induced by the pumping system. The demonstrated sensitivity reaches a minimum detectable absorption of 7.8 × 10⁻⁷ cm⁻¹ over an 18 m effective path length in the jet core. This work illustrates the potential of cavity-enhanced direct frequency comb spectroscopy for precise spectroscopic characterization of cold supersonic expansions, with implications for studies in molecular dynamics, reaction kinetics, and laboratory astrophysics. Full article

An optical fiber sensor based on a HEMA/AM/SA interpenetrating polymer network (IPN) hydrogel is proposed for monitoring the concentration of Pb²⁺. The Fabry–Perot interference cavity is constructed from a single-mode fiber, a ceramic ferrule, and an IPN hydrogel layer. P (HEMA co AM)/SA IPN hydrogel films were prepared by a step-by-step crosslinking method, which had good mechanical properties, swelling properties, and Pb²⁺ adsorption capacity. The Pb²⁺ concentration changes cause the interference spectrum shift of the sensor. By monitoring the wavelength shift under different Pb²⁺ concentrations, the sensor sensitivity in the range of 0~1 ppm Pb²⁺ concentration in solution is 5.0743 nm/ppm with 0.994 linearity. The influence of different proportions of IPN hydrogel on the performance of the sensor was studied. In the range of 10–90% HEMA, higher sensitivity is obtained by a small weight ratio of HEMA/AM. The sensor stability, repeatability, selectivity, dynamic response, and temperature response are also investigated in experiments. Experimental results demonstrate that the proposed sensor exhibits good stability, sensitivity, repeatability, and selectivity. Owing to its compact structure, straightforward fabrication, low cost, and good sensing performance, this sensor shows strong potential for application in monitoring Pb²⁺ concentrations. Full article

Background/Objectives: The principal function of pharmaceutical blister packaging is to provide protection for the drug product. Moisture is regarded as a critical factor in the physical and chemical aging of drug products. The present work proposes a modeling framework to predict the performance of tablet blister materials based on the moisture uptake profile of the drug product as well as degradation characteristics of the drug substance, while the consumption of water due to degradation is included. Methods: The model incorporates three kinetic superimposed processes that define moisture uptake and drug stability. The processes of permeation, sorption and degradation are each described with a rate constant. Based on a mass balance, these rate processes are interconnected and the relative humidity in the blister cavity is predicted. Results: In a case study, the model was applied to demonstrate the feasibility of predicting the stability of blistered tablets. By establishing a correlation between the moisture uptake of the tablet and the drug stability demonstrated in the model, it was feasible to predict the drug content over shelf life. Conclusions: Modeling of the drug stability of blister-packed products enables a rational packaging which offers novel possibilities for reducing material in order to avoid overpackaging of pharmaceutical products. As some of the commonly used barrier materials are considered to not be sustainable, this model can be used to consider a rationally justified reduction or even abandonment of the barrier materials. Full article

Plastic injection molding is a widely used manufacturing process for producing plastic components. However, achieving optimal process stability and part quality remains a persistent challenge due to limited real-time feedback during production. The main objective of this study is to present a method to overcome this limitation by integrating in-mold cavity pressure sensors with an Iterative Learning Control (ILC) strategy to optimize key processing parameters autonomously. The ILC methodology established a closed-loop system; over successive production cycles, cavity pressure profiles were analyzed to automatically adjust the holding pressure, holding time, and switchover point. Each iteration refined the parameters based on sensor data, creating a learning-based optimization loop that accelerated the convergence to optimal settings. The methodology was validated by producing an automotive plastic component. The results demonstrate a 100% success rate in correcting ten critical dimensional errors, fulfilling all part tolerances. Additionally, the overall cycle time decreased by 8%, from 55.0 to 50.6 s. Other findings included updates to key process molding parameters, such as reducing holding pressure from 250 to 230 bar and holding time from 18 to 12 s, as well as increasing the switchover point from 41 to 72 mm. This research confirms that combining real-time cavity pressure monitoring with ILC offers a strong, data-driven framework for significantly improving quality, efficiency, and process stability in injection molding. Full article

Background: Glioblastoma (GBM), IDH-wildtype, is one of the most aggressive primary brain malignancies, and maximal safe resection is consistently recognized as a significant prognostic factor. Intraoperative adjuncts including functional mapping, neuronavigation, and fluorescence-guidance are not always present in many centers around the world. The aim is not to suggest equivalence to adjunct-assisted resections, but rather to illustrate the feasibility of anatomy-guided surgery in carefully selected cases and to contribute to the broader discussion on safe operative strategies in resource-limited environments. Methods: We present the case of a 54-year-old right-handed male who presented with progressive non-fluent aphasia, seizures, and signs of intracranial hypertension. Pre-operative MRI showed a heterogeneously hyperintense, frontobasal intra-axial mass involving the dominant inferior frontal gyrus, extending toward the corpus callosum and orbitofrontal cortex, and early subfalcine shift. Surgery was performed via a left frontobasal craniotomy, using subpial dissection and cortical–sulcal anatomical landmarks while aiming to preserve eloquent subcortical tracts (frontal aslant tract, superior longitudinal fasciculus). Nueronavigation, functional mapping or fluorescence was not used. We defined our outcomes by the extent of resection, functional preservation, and early radiological stability. Results: The procedure achieved a subtotal-near-total resection (>95% estimated volume) while maintaining functional motor function from prior to surgery and the patient’s baseline expressive aphasia, with no new neurological deficits. Early post-operative CT showed decompression of the resection cavity without hemorrhage or shift. At three months post-operative, CT showed stability of the cavity and resolution of the most perilesional edema with no evidence of recurrence. Clinically, the patient showed gradual improvement in verbal fluency, he remained seizure free, and maintained independence, which allowed for timeliness of the initiation of adjuvant chemoradiotherapy. Conclusions: We intend for the case to illustrate that, in selected dominant frontal GBM, following microsurgical anatomical principles closely may provide a high extent of resection with the preservation of function, even without advanced intraoperative adjuncts. We hope that our experience may support our colleagues who practice in resource-limited settings and contribute to our shared goal of both oncological outcomes and the quality of life of our patients. Full article

Background: Obstructive sleep apnea syndrome (OSAS) and impaired nasal breathing are common in children and are frequently linked to maxillary constriction. Rapid maxillary expansion (RME) is an orthopedic treatment used to increase upper airway dimensions and improve respiratory function. It has been hypothesized that RME could contribute to improvements in behavior and cognition, possibly through enhanced sleep and respiratory function. It also promotes the shift from oral to nasal breathing, supporting craniofacial development and neuromuscular stability, and it is increasingly recognized as a multidisciplinary intervention that can improve pediatric health outcomes. With increasing evidence supporting its efficacy, RME should be considered not only for its orthodontic benefits but also as a multidisciplinary treatment option within pediatric care protocols. This underscores the importance of integrated care among orthodontists, ENT specialists, and pediatricians. Aim: To systematically assess the impact of RME on nasal respiratory parameters and sleep-disordered breathing, particularly OSAS, in pediatric patients. Methods: Following PRISMA guidelines, a systematic review was conducted using 12 clinical studies evaluating anatomical and functional respiratory changes after RME in children with mouth breathing or OSAS. Parameters included airway volume (CBCT, cephalometry), nasal resistance (rhinomanometry), and polysomnography (PSG) data. Results: RME consistently resulted in significant increases in nasal cavity volume and upper airway dimensions. Multiple studies reported reductions in the apnea–hypopnea index (AHI), improved oxygen saturation, and better subjective sleep quality. Longitudinal studies confirmed the stability of these benefits. However, variability in study protocols limited meta-analytical comparison. Conclusions: RME is effective in enhancing nasal breathing and mitigating OSAS symptoms in children. While results are promising, further high-quality randomized controlled trials are needed to validate these findings and guide standardized treatment protocols. Full article