Stability Field Research Articles

Does tidal volume during mechanical ventilation affect pediatric retrograde intrarenal surgery outcomes?

The aim of the study was to analyze the effect of tidal volume during mechanical ventilation (MV) on pediatric retrograde intrarenal surgery (RIRS) outcomes. The data of patients who underwent RIRS between January 2018 and January 2023 were retrospectively analyzed. Patients under the age of 18 who underwent RIRS and whose data were available were included in the study. Patients were divided into two groups, ≤ 7ml/kg (Group 1) and > 7ml/kg (Group 2), according to the tidal volume during MV. Demographic data, clinical characteristics, and perioperative and postoperative data of the patients were statistically compared in both groups. A total of 83 patients were enrolled, with a mean age of 6.9 ± 4.5 (1-17) years and a mean stone size of 11.7 ± 5.4 (5-33) mm. There were 31 patients in Group 1 and 52 patients in Group 2. The demographic data and clinical characteristics of the patients in both groups were comparable. There was no statistically significant difference between the two groups regarding stone-related (side, size, density, number, and location) and surgical (access sheath and basket use, operation time, fluoroscopy time, or postoperative stenting rates, complication rates) parameters. In the first month, the stone-free rate was higher in Group 1 than in Group 2 (90.3% vs. 71.1%, p = 0.03). No high-grade or anesthesia-related complications were observed in any of the patients. Reducing tidal volume in pediatric RIRS may improve the stone-free rate by facilitating laser targeting and increasing operative field stability and surgical comfort.

Impaired spatial coding of the hippocampus in a dentate gyrus hypoplasia mouse model

The hippocampal dentate gyrus (DG) is thought to orthogonalize inputs from the entorhinal cortex (pattern separation) and relay this information to the CA3 region. In turn, attractor dynamics in CA3 perform a pattern completion or error correction operation before sending its output to CA1. In a mouse model of congenital hypoplasia of the DG, a deficiency in the Wntless (Wls) gene, specifically in cells expressing Gfap-Cre, which targets neuronal progenitors, led to an almost total absence of dentate granule cells and modestly impaired performance in spatial tasks. Here, we investigated the physiological consequences of granule cell loss in these mice by conducting in vivo calcium imaging from CA1 principal cells during behavior. The spatial selectivity of these cells was preserved without the DG. On a linear track, place fields in mutant mice were more likely to be near track terminals and to encode the distance from the start point in each running direction. In an open box, CA1 cells in mutant mice exhibited reductions in the percentage of place cells, in spatial information, and in place field stability. The reduction in place field stability across repeated exposures to the same environment resulted in a reduction in the differential representations of two different contexts in mutant mice compared to wild-type mice. These results suggest that DG helps to stabilize CA1 spatial representations, especially in 2-D environments, and that the lack of stability across similar environments may play a key role in the deficits of animals with DG dysfunction in discriminating different environments.

Proteinex Bait Gel Formulations Suitable for Increased Field Stability and Enhanced Trapping of Melon Fly (Zeugodacus cucurbitae) Coquilette

Cucurbit fruit fly, Zeugodacus cucurbitae is an important insect pest of cucurbits. Fruit flies consisted of over 250 species worldwide and its maggots damage fruit from inside and hence, insecticides remain practically ineffective. Trapping the adult flies through parapheromenes, protein and food based traps is the most common practice. The protein and food baits attract both sexes over the parapheromones and are more effective due to their attractiveness and comparatively less weathering under field conditions. Hence, the present study was undertaken to prepare gel based formulations of liquid proteinex bait to increase it’s trapping efficiency. The gelling agents viz., xanthan gum powder, gaur gum powder, pectin powder, carrageenan powder, sodium alginate and gum arabic powder were used to prepare gel formulations of liquid proteinex bait developed by us. Among them, pectin and xanthan gum powders turned the liquid proteinex bait to semi-liquid at very less concentrations thus making them economical to use. Pectin, guar gum and carrageenan powder gel formulations maintained semi-liquid to slightly thickened consistency up to 9th day after preparation of bait and is advantageous for stability under field conditions. Protein content of pectin and guar gum powder formulations are similar as liquid proteinex bait which contributes for more attraction. pH of pectin and guar gum powder gel formulations was higher than the liquid proteinex bait thus increasing their attractiveness. As viscosity of pectin and carrageenan powder formulations was close to liquid proteinex bait, acceptability of these baits closely follows that of liquid bait. Study concluded that pectin powder gel formulation of liquid proteinex bait was found to be ideal and economical to use in field conditions to attract both male and female fruit flies.

The impact of fiscal policy on achieving monetary stability in Iraq: an analytical study for the period 2004-2020

The Iraqi economy faces many economic crises, which negatively affect the monetary stability of Iraq, and the research aims to know the impact of financial policy tools in achieving monetary stability, and any of these tools that have the greatest impact in achieving the goal of monetary stability, and in order to reduce the efforts made by officials About setting the financial policy in order to achieve the best results and so that they can develop future plans that have a greater impact on the economy. The importance of the research stems from the importance of monetary stability and the positive or negative effects it causes in the economy. It is concluded through the research that the effect of fiscal policy is weak in reaching the goal of monetary stability for Iraq in light of the fluctuations and fluctuations that occur in the financial policy tools. However, public expenditures as a tool for fiscal policy have the greatest impact compared to other tools of fiscal policy in the field of monetary stability.

RF Heating Effects in CEST NMR with Hyperpolarized 129Xe Considering Different Spin Exchange Kinetics and Saturation Schemes.

Chemical exchange saturation transfer (CEST) improves the sensitivity of NMRbut depending on the spin exchange kinetics, it can require substantial RF energy deposition to label magnetization. Potential side effects like RF-induced heating may occur and must be monitored. Here, we explore the parameter space considering not only undesired heating but efficient CEST build-up (depolarization rate), spectral resolution (line width), and subsequent effects like changes in chemical shifts of CEST responses must be considered, too. We present a systematic study to compare conventional block pulse with shaped-pulse saturation and quantify how the effective average saturation power impacts these parameters. Pulse shape and nominal excitation bandwidth, however, turned out to have little impact on acquired z-spectra and temperature changes. This study illustrates how different exchange kinetics define different regimes of suitable RF power within the dynamic range of fully saturable magnetization from hyperpolarized 129Xe. Temperature-related changes in the resonance frequency of bound spins were also quantified for the two Xe hosts CB6 and CrA-ma and put into context for typically used CEST acquisition parameters, including the stability of the magnetic field.

Characterisation of the Overflow Pipe Structure on the Internal Flow Field of a Hydrocyclone

The application of cyclones can be traced back to 100 years ago. Salt, an important carrier of energy exchange in the human body, is one of the essential substances. Currently, salt surface impurities are mostly removed manually, resulting in low sorting efficiency. Cyclones, as important physical separation equipment, are widely used in separating different substances. This paper focuses on using cyclones for salt decontamination. However, due to the limitations of the cyclone’s structure, ensuring grading accuracy is challenging. The flow field, as the main power source in the cyclone grading process, significantly impacts the grading effect. The overflow pipe, where fine particles exit, has a significant effect on the internal flow field. To explore the impact of the overflow pipe structure on the cyclone’s internal flow field, five overflow pipe structures were designed and numerically analyzed. The results indicate that the improved overflow tube structure has higher static pressure than the conventional linear structure. Type 2 (Parabolic) has the highest tangential velocity, which is 27.7 percentage points higher than that of the conventional cyclone, while Type 3 (hyperbola) has the lowest axial velocity(minimum value is only 0.3 m/s) and turbulence intensity(minimum value of the cone segment is only 0.2), resulting in longer particle residence time in the cyclone for better separation. Additionally, vortices are effectively avoided, improving the stability of the flow field to some extent. The obtained data provide a theoretical basis and support for the structural design of new cyclones.

Exceptional field emission characteristics of self-assembled carbon nanotube sheets with ultra-low turn-on field and outstanding stability

Exceptional field emission characteristics of self-assembled carbon nanotube sheets with ultra-low turn-on field and outstanding stability

Study on numerical simulation of groundwater flow field and slope stability in multi-aquifer open pit mine

Water is one of the most important influences on slope stability in open pit mines. In order to solve the problem of slope stability analysis in multi-aquifer open pit mines, the open pit mine in Block I of Thar Coalfield in Pakistan with multiple aquifers was taken as the research background. The groundwater flow field at different excavation phases was analyzed by numerical simulation method. Based on the seepage theory of groundwater, the distribution law of hydrostatic pressure in phreatic aquifer and confined aquifer was analyzed. Based on the rigid body limit equilibrium method, the slope stability analysis method under the action of hydrostatic pressure of multiple aquifers was proposed. Based on the water level distribution within the slope body obtained by numerical simulation, the slope stability at different excavation phases was calculated, and the influence of aquifers on slope stability was analysed. The research results show that: With the excavation and drainage of the mine pit, the groundwater flow field in the open pit mining area changes significantly, and a descending funnel was formed at the mine pit. When mining reached the pit bottom boundary, the water level dropped by about 155–163 m in the mining area. The hydrostatic pressure action of aquifer on slope is related to water level, quantity and location of aquifer. Under the condition of considering hydrostatic pressure of aquifer, the slope stability coefficients are all reduced. And the slope stability coefficients of the three different mining phases were reduced by 6.74%, 11.87%, and 5%, respectively. The more aquifers the sliding surface crosses, the greater the effect of hydrostatic pressure on slope stability. When mining to the boundary, the combined sliding surface passed through two aquifers, and the slope stability coefficient decreased by 5% under the hydrostatic pressure condition, and the arc sliding surface passed through three aquifers, and the slope stability coefficient decreased by 8.74% under the hydrostatic pressure condition. The stability of slope with arc sliding mode is more affected by aquifer hydrostatic pressure than that with combined sliding mode. When mining to the floor of the coal seam roof confined aquifer, the stability coefficient of slope with combined sliding surface decreased by 11.87%, while that with arc sliding mode decreased by 16.32%.

Advanced Nanostrategies for Biomolecule Delivery in Plant Disease Management.

Sustainable plant disease management has long been a major issue in agriculture since the excessive reliance on broad-spectrum pesticides exacerbates chemical resistance, presenting environmental and health hazards. Taking cues from nature's intricate defense mechanisms, scientists are exploiting bioactive agents involved in plant-pathogen/pest interactions to develop novel strategies to combat diseases. Embracing biomolecules in agriculture offers an ecofriendly alternative to chemical pesticides. However, traditional delivery methods for biomolecules often suffer from low utilization rates and low field stability, diminishing the overall effectiveness of active compounds. The advent of nanotechnology has facilitated the design of novel delivery systems for biomolecular cargos, further enhancing their capacity to adhere to plant surfaces and make disease control strategies effective. Tailored depending upon the extent of infection and type of plant species, innovative nanoparticle strategies maximize the effectiveness of delivery by modifying the size, surface characteristics, and adhesion capacity of the particles to suit particular requirements. This review examines how the various biological factors involved in innate plant defenses can be exploited, as well as the potential of various nanocarriers in biomolecule delivery for plant disease management.

Analytical and Computational Investigation of VibroThermoAcoustic Behaviour of Cracks in Aerostructures

Abstract This research investigates the Vibro-thermoacoustic dynamics exhibited by Aerostructures, particularly those harbouring surface cracks. Employing a novel approach, a Thermo-Acoustic field coupled Transient Heat Transfer model is developed to model the interplay among vibrations, heat dissipation, and acoustic behaviour at crack tip interfaces. Local surface flaws proximal to stress concentration sites are investigated via the Newmark Beta Method and Finite Element Analysis, which are applied to displacement and thermal mapping at crack tips through temporal and spatial discretization. Recognizing the implications of flaws in structural integrity and potential lifespan reduction, the study incorporates Analytical, Numerical and Computational analysis of surface cracks into the broader context of Thermoacoustic phenomena. 
The paper explores the application of Elastoplastic Fracture Mechanics (EPFM) to model the impact of plastic deformation on crack growth, local acoustic field and the overarching structural integrity of these components. 
In this study, we also investigate the limitations of the original Ramberg-Osgood equation, particularly in its application to modelling nonlinearities in plastic strain at crack tip interfaces. To address these shortcomings, we propose a novel modified Ramberg-Osgood formulation that incorporates Padé Approximants. This modification enables effective modelling of nonlinear stress-strain variations of high-performance materials while improving computational performance and accuracy. 
Real-world aerostructures experience varying loads, and incorporating these principles in our coupled model allows for accurate modelling of Thermoacoustic Field variations and Instability under dynamic conditions. The research offers valuable perspectives for engineering applications, providing a computational roadmap for thermoacoustic modelling in Aerostructures with cracks.

Hydrochemical Characteristics and Genesis of Sand–Gravel Brine Deposits in the Mahai Basin of the Northern Qinghai–Tibetan Plateau

The sand–gravel brine deposit in the Mahai Basin is a newly discovered large-scale potassium–bearing brine deposit. The potassium–bearing brine is primarily found at depths exceeding 150 m within the porous alluvial and fluvial sand–gravel reservoir of the Middle to Lower Pleistocene. This deposit is characterized by a relatively shallow water table, moderate–to–strong aquifer productivity, high salinity, and a KCl content that meets the conditions for exploitation, with the advantage of reduced salt crystallization during well mining, making it a potential reserve base for potash development. A geochemical analysis of the sand–gravel brine revealed consistent trends for the major ions K+, Na+, Mg2+, Cl−, and SO42− along the east–west axis of the alluvial fan, while Ca2+ showed an opposite trend compared to Mg2+. Along the exploration lines from north to south, the concentrations of the main ions gradually increase. The brine is enriched in Na+ and Cl− ions, while SO42− and HCO3− are depleted. In the K+-Na+-Mg2+/Cl−-H2O (25 °C) quaternary phase diagram, the brine falls within the halite stability field, with the hydrochemical type classified as chloride type. The brine coefficient characteristics indicate a multi-source origin involving residual evaporation, salt rock leaching, and metamorphic sedimentary brine. Comparison studies of the ionic composition and isotopic signatures (δD, δ18O, δ37Cl, and δ7Li) of deep sand–gravel brines in the study area with interstitial and confined brines in the southern depression suggest similar geochemical characteristics between them. The genetic analysis of the deposit proposes that during the basin tectonic evolution, the potassium-rich interstitial and confined brines originally located in the southern depression of the Mahai Basin were displaced under compressional forces and migrated northward as the depositional center shifted, eventually backfilling into the loose alluvial and fluvial sand and gravel reservoirs at the front of the Saishiteng Mountains, forming the deep sand–gravel brine deposits in the foreland.

A quench detection method for closed-loop superconducting coils based on currents redistribution in co-windings

Abstract Closed-loop operation of superconducting magnets can significantly reduce cryogenic heat load and enhance magnetic field stability, which has been widely applied in systems such as magnetic resonance imaging and electro-dynamic suspension. Quench detection for closed-loop superconducting magnets, especially high-T c superconducting (HTS) magnets, has long been a challenging issue. In this paper, we derived quench-induced currents redistribution characteristics in parallel co-wound closed-loop superconducting magnets, and proposed a current-redistribution based quench detection method for such magnets. Artificial quench tests on a small scale co-wound closed-loop HTS coil were staged, with AC background magnetic field applied to simulate tough working conditions such as in HTS maglevs and HTS machines. Results show that the method can sensitively and reliably detect a quench even at its inception, long before the coil field change becoming identifiable, and the method is robust against background AC magnetic fields. This work may potentially be useful for reducing the quench damage risk in closed-loop superconducting magnet for various applications.

Estimating the Electric Fields Driving Lightning Dart Leader Development With BIMAP‐3D Observations

AbstractIn this paper, a numerical dart leader model has been implemented to understand the leader's development and the corresponding electric field changes observed by the 3D broadband mapping and polarization (BIMAP‐3D) system. The model assumes the extending leader channel is equipotential and has a linear charge distribution induced by an ambient electric field. The charge distribution induced by the ambient field can be used to model the electric field change at the ground. We then find the ambient electric field which best fits the field change measurements at the two BIMAP stations. The estimated ambient electric field decreases in the direction of dart leader propagation. Our observations and modeling results are consistent with our earlier hypothesis that dart leader speed is proportional to the electric field at the leader tip. The model also supports our earlier analysis that leader speed variations near branch junctions were due to previous charge deposits near the junctions. The modeled tip electric field is generally lower than the breakdown field unless the pre‐dart‐leader channel has a significant temperature of 3,000 K. This is consistent with the fact that dart leaders typically do not form new branches into the virgin air. Furthermore, the tip field is generally close to the negative streamer stability field at ambient temperatures, explaining the nature of the narrow and well‐defined channel structure. In addition to the charge distribution and the ambient and tip electric field, the development of the channel potential and current distribution are also presented.

Insights into fractal space features in nonlinear electrohydrodynamic Rayleigh–Taylor instability of viscous fluids

This paper describes a unique method for detecting and evaluating nonlinear Rayleigh–Taylor instability (RTI) in electro-viscous fluids exposed to an external vertical electric field. The governing equations are based on a linearized Navier–Stokes framework with nonlinear boundary conditions, capturing the system's complexity. Using a traveling wave transformation, the analysis reduces the system's complicated dynamics to a nonlinear characteristic equation in the elevation function that includes quadratic and cubic nonlinearities. The strategy utilizes El-Dib's frequency formula, which allows for the derivation of an equivalent linearized form of the characteristic equation, simplifying the nonlinear equation and making it more tractable for analytical investigation. The study emphasizes the critical function of the electric field in the system's stability. Smaller electric fields improve stability and equilibrium, resulting in damped oscillations that maintain the fluid–fluid interface. Larger electric fields, on the other hand, enhance instabilities, causing the system to behave nonlinearly, which might lead to chaotic motion if the oscillations are severe. The analysis is extended to convert the characteristic equation into a fractal space description. The fractal derivative form enables the modeling and study of complicated, nonlinear, and chaotic processes commonly encountered in fluid dynamics problems. This methodology is especially well-suited to handling multi-scale dynamics and nonlinear growth in RTI. The influence of fractal factors on system behavior is examined. Increasing the fractal order consistently has a stabilizing effect, lowering the oscillation amplitude and increasing damping, hence improving stability. In contrast, raising the fractalness parameter introduces a destabilizing influence, resulting in bigger oscillations and lower damping, destabilizing the system over time. This study sheds light on the behavior of nonlinear RTI in electro-viscous fluids in the presence of electric fields and fractal dynamics.

Geochemistry of garnet and scheelite as indicators for skarn-type Mo-W mineralization: A case study from the Shibaogou deposit, Qinling Orogen, China

To understand the mechanism of skarn-type Mo-W mineralization, it is crucial to study fluid evolution. In-situ elemental analysis was conducted on garnet and scheelite from the Shibaogou deposit, a representative large-scale skarn Mo-W deposit in Luanchuan orefield, Qinling orogen, aiming to constrain the origin and evolution of ore-forming fluid and to analyze the skarn mineralization process. Multiple generations of garnet and scheelite were observed along with the multistage of skarnization. I. Anhydrous skarn stage, three generations of garnet (Grt-c, Grt-m, Grt-r) with molybdenite (Mo-I) occurring around Grt-r and scheelite occurring in coarse-grained (primary Sch-I, altered rim Sch-Ia). II. Hydrous skarn stage, minor scheelite (Sch-II) coexisted with actinolite. III. Oxide stage, scheelite (Sch-III) occurred in feldspar-fluorite veins, with minor molybdenite (Mo-II). IV. Quartz sulfide stage, early quartz-molybdenite (Mo-III) veins and later quartz Fe-Zn-Pb-sulfide veins occurred with a few scheelites (Sch-IV). V. Carbonite stage.The Y/Ho ratios of garnet and scheelite indicate that the ore-forming fluid was originally magmatic-hydrothermal. The variations in U and Sn contents of garnet indicate a gradual increase in oxidation state during the anhydrous skarn stage. The high andradite proportion in Grt-m resulted from an increased pH of the fluid, related to the presence of Ca(HCO3)2. This increased pH and Ca2+ activity of fluid led to the main tungsten mineralization (Sch-I). The subordinate Mo mineralization formed at the end of stage I, as the expansion of the molybdenite logfO2-pH stability field, controlled by the decrease in temperature. The redox state evolutions indicated by the consistent Mo contents and (EuN vs. EuN*) of scheelite, with the highest oxidation state occurring in the hydrous skarn stage. The oxidation state reached the lowest level in the sulfide stage with sufficient reduced sulfur, leading to main Mo mineralization. The REE patterns, Nb, and ∑REE contents of scheelite suggest a change in fluid composition to F enrichment after anhydrous skarn, which enhanced the fluid’s ability to dissolve W. In the oxide stage, scheelite formed a second significant mineralization with fluorite: H3WO4F2– + 2Ca2+ = CaWO4 + CaF2 + 3H+. The carbonate wall rocks played a controlling role in the evolution of ore-forming fluid and mineralization mechanism through the fluid-rock interactions.

Seventeen Million Years of Episodic Volcanism Recorded Within the Geologist Seamounts: Implications for Tectonic Drivers of Intraplate Volcanism

AbstractUpwelling and decompression of mantle plumes is the primary mechanism for large volumes of intraplate volcanism; however, many seamounts do not correlate spatially, temporally, or geochemically with plumes. One region of enigmatic volcanism in the ocean basins that is not clearly attributable to plume‐derived magmatism is the Geologist Seamounts and the wider South Hawaiian Seamount Province (∼19°N, 157°W). Here we present new bathymetric maps as well as 40Ar/39Ar age determinations and major and trace element geochemistry for six remote‐operated vehicle recovered igneous rock samples (NOAA‐OER EX1504L3) and two dredged samples (KK840824‐02) from the Geologist Seamounts. The new ages indicate that volcanism was active from 90 to 87 Ma and 74 to 73 Ma, inferring that in conjunction with previous ages of ∼84 Ma, seamount emplacement initiated near the paleo Pacific‐Farallon spreading ridge and volcanism spanned at least ∼17 m.y. Geochemical analyses indicate that Geologist Seamount lava flows are highly alkalic and represent low‐degree partial mantle melts primarily formed from a mixture of melting within the garnet and spinel stability field. The ages and morphology inferred that the seamounts were likely not related to an extinct plume. Instead, we build upon previous models that local microblock formation corresponded to regional lithospheric extension. We propose that the microblock was bounded by the Molokai and short‐lived Kana Keoki fracture zones. Regional deformation and corresponding volcanism among the Geologist Seamounts associated with the microblock potentially occurred in pulses contemporaneous to independently constrained changes in Pacific Plate motion—indicating that major changes in plate vectors can generate intraplate volcanism.

Role of the Water–Rock System in the Formation of the Composition of Radon Water of the Tulinskoe Field (Novosibirsk)

Abstract ––We present the first results of comprehensive isotope-geochemical studies of mineral radon waters of the Tulinskoe field (Novosibirsk), aimed at identifying their stages of interaction with the host rocks. By geochemical coefficients Ca/Na, Ca/Mg, Ca/Si, Mg/Si, Na/Si, Si/Na, rNa/rCl, and SO4/Cl, the studied waters are assigned to fracture–vein waters of granitoids. The indices of carbonate mineral saturation of the radon waters show their oversaturation with aragonite, calcite, and dolomite. The waters are also saturated with diaspore, ferrohydrite, gibbsite, and kaolinite, which leads to the deposition of these minerals as secondary phases. In the thermodynamic diagrams, the points of the activities of the radon water components are localized mainly in the stability fields of clay minerals (kaolinite and Na-, Ca-, and Mg-montmorillonites), layered silicates (talc), and zeolites (laumontite). A few points fall in the stability field of silicates (Mg-chlorite). The studied waters of the Tulinskoe field are neutral fresh, with Si = 6.41–9.02 mg/dm3. According to the results of thermodynamic calculations, the radon waters of the Tulinskoe field are in equilibrium with carbonate minerals and hydromicas. Following the classification by S.L. Shvartsev, they are assigned to the Si-Na geochemical type.

Identifying critical transmission lines in cascading outages using the natural connectivity index

This paper presents a novel method for identifying critical transmission lines (CTLs) in power systems subjected to cascading overload outages, leveraging the Natural Connectivity (NC) index. Unlike previous studies that employed suboptimal weights for the edges, this work introduces a new weighting strategy that enhances the effectiveness of NC in CTLs identification. The proposed Weighted Natural Connectivity-based (WNC-based) method is validated through comparisons with established methods, including the catastrophic expectation index, and the cascading failure simulation index, using IEEE test systems of 30, 39, 57, and 118 buses and the 400 kV Mexican power system. The experimental results demonstrate that the WNC-based method accurately identifies critical lines, providing a practical balance between simplicity and precision. This study challenges prior conclusions that natural connectivity is unsuitable for CTLs identification, showcasing its potential in power system applications. Furthermore, the method's applicability extends to interconnected systems, such as the integration of power transmission, gas distribution, and telecommunication networks, paving the way for future research. The WNC-based method offers a practical tool for preventing blackouts and enhancing power grid resilience, contributing significantly to the field of power system reliability and stability.

Apatite as an indicator of tectono-magmatic evolution of silica-undersaturated to silica-oversaturated rocks on the NW Indian Plate margin

Permo-Carboniferous intrusive rocks situated on the NW boundary of the Indian Plate between the Main Mantle Thrust (MMT) and Main Boundary Thrust (MBT) have tremendous potential for enhancing our knowledge of regional tectono-magmatic activity in Pakistan, yet these units have received only limited investigation to date. Here, we examine the petrology, apatite geochemistry and Sr-Nd isotopes, and geochronology of the silica-undersaturated (sodalite syenite and nepheline syenite), silica-saturated (monzonite and quartz syenite), and silica-oversaturated (granite and quartz monzonite) intrusive suites of the Ambela Granitic Complex (AGC) in northern Pakistan. Cathodoluminescent (CL) images of apatite in the three suites show mostly oscillatory zonation and a homogenous texture. The apatite chemistry of three intrusives is characterized by high fluorine (F), rare earth element (REE), yttrium (Y), and thorium (Th) contents, and low levels of chlorine (Cl), iron oxide (FeO) and magnesium oxide (MgO), suggesting a magmatic origin. The three suites exhibit variation in Sr-Nd isotopes, i.e., 87Sr/Sr86i = 0.7035 to 0.7057 and εNd(t) = +0.3 to +6.0 for the silica-undersaturated group, 87Sr/Sr86i = 0.7044 to 0.7205 and εNd(t) = +1.8 to +3.8 for the silica-saturated group, and 87Sr/Sr86i = 0.7075 to 0.7186 and εNd(t) = −2.5 to +1.2 for the silica-oversaturated group. Garnet stability field indicators in the nepheline syenite imply a deeply sourced magma, with Sr-Nd isotopic, and trace-element compositions of the apatite indicating formation in the subcontinental lithospheric mantle. In contrast, the silica-oversaturated melts formed during magma ascent through crustal interactions at a range of depths, with their apatites showing affinity with A-type granites. Apatite grains from the three magmatic groups show distinctive Sr, Eu and Y patterns, reflecting less fractionation of the silica-undersaturated and -saturated suites than of the silica-oversaturated suite. Furthermore, apatites of the former suites have higher Eu/Eu* and SO3 and lower Ce/Ce* than those of the latter suite, suggesting development under more oxidizing magmatic conditions. TDM2 ages demonstrate parent material of Mesoproterozoic to Neoproterozoic age, whereas LA-ICP-MS U-Pb dating of magmatic apatite indicates cooling of all suites concurrently at ∼322–262 Ma. The latter ages document significant magmatic activity in the study region during the Late Carboniferous to Middle Permian, probably in connection with rifting of the northern margin of the supercontinent Gondwana, leading to opening of the Neo-Tethys Ocean.

Study of magnetic field error suppression methods based on atomic parameters of cell in atomic co-magnetometer rotation measurement

Abstract We propose a new model for magnetic field errors based on the rotation measurement of the K-Rb- 21 Ne co-magnetometer, considering the density ratio and spin collisions. The spin polarization characteristics of different alkali metal density ratios were analyzed by creating five cells with different density ratios, and the correctness of the magnetic field error model was verified experimentally. Moreover, the effects of five different alkali metal density ratios of cells on the sensitivity, long-term stability and magnetic field error suppression of the K-Rb- 21 Ne co-magnetometer were investigated experimentally. When the density ratio is 1:107, there can be the optimal magnetic field error suppression effect, sensitivity and long-term stability. According to the derived magnetic field error equation, the magnetic noise error of the K-Rb- 21 Ne co-magnetometer with an optimized density ratio is reduced by nearly 5 times from 260°/h/nT to 56.5°/h/nT, the sensitivity is improved from 2.9×10−5 °/s/Hz 1 / 2 to 7.0×10−6 °/s/Hz 1 / 2 at 1 Hz, and the long-term stability Allan variance over two hours is improved from 1.9×10−2 °/h to 8.9×10−3 °/h. This result provides a theoretical basis for designing the parameters of the K-Rb- 21 Ne co-magnetometer cell.