Systemic Pressure Research Articles

Numerical and analytical modelling of wellbore storage effects in low-enthalpy geothermal well tests

In geothermal wells, build-up phases of well tests are typically executed with a surface shut-in, rather than with a downhole shut-in. Therefore, wellbore physics may play a dominant, but undesirable, role in the system's pressure response as recorded by the downhole pressure gauge. Numerical simulations were carried out to investigate to what extent these effects complicate the analysis of the well test and the deduction of the reservoir characteristics. Numerical models, supported by analytical modelling of well tests of field cases, show that significant portions of the Bourdet derivatives of geothermal well tests are expressions of physical effects in the wellbore, rather than the reservoir's pressure response. These wellbore storage effects in low-enthalpy geothermal wells are more intense than commonly reported in the literature. In addition, they may last for a very long time and vary continuously during the build-up. They cannot be represented accurately with the known analytical solutions commonly available in analytical well-test software. In many cases the early, middle and late time regions of the reservoir response on the derivative plot have only developed partially, or might be completely missing. Due to their intensity and duration, the wellbore storage effects can obliterate the true reservoir response, thereby making a reliable analysis of the reservoir characteristics impossible. This will undoubtedly lead to incorrect interpretations of the skin or reservoir properties. It is therefore strongly recommended that well tests in geothermal wells are executed using a downhole shut-in device, such that the unwanted wellbore physics are fully eliminated and the downhole pressure gauges only measure the true reservoir response.

Deep Neural Network for Valve Fault Diagnosis Integrating Multivariate Time-Series Sensor Data

Faults in valves that regulate fluid flow and pressure in industrial systems can significantly degrade system performance. In systems where multiple valves are used simultaneously, a single valve fault can reduce overall efficiency. Existing fault diagnosis methods struggle with the complexity of multivariate time-series data and unseen fault scenarios. To overcome these challenges, this study proposes a method based on a one-dimensional convolutional neural network (1D CNN) for diagnosing the location and severity of valve faults in a multi-valve system. An experimental setup was constructed with 17 sensors, including 8 pressure sensors at the inlets and outlets of 4 valves, 4 flow sensors, and 5 pressure sensors along the main pipe. Sensor data were collected to observe the sensor values corresponding to valve behavior, and foreign objects of varying sizes were inserted into the valves to simulate faults of different severities. These data were used to train and evaluate the proposed model. The proposed method achieved robust prediction accuracy (MAE: 0.0306, RMSE: 0.0629) compared to existing networks, performing on both trained and unseen fault severities. It identified the location of the faulty valve and quantified fault severity, demonstrating generalization capabilities.

A correlation study of arterial stiffness with P300 event-related potential in non-haemodialytic and haemodialytic chronic kidney disease patients of renal origin

Introduction: Chronic kidney disease (CKD) is associated with hypertension. The renal micro-vessels are vulnerable to the pulsatile nature of systemic pressure leading to arterial stiffness, which may lead to progressive renal disease besides other mechanisms. The stiffened cerebral vasculatures may also cause neural injury. Thus, cognitive impairment is prevalent in CKD patients. However, very few studies have attempted to examine the association of arterial stiffness with P300 event-related potential (P3ERP) in CKD patients of primary renal disease in the Indian population, which forms the basis of the study. Materials and Methods: Twenty-three age- and sex-matched non-haemodialytic and haemodialytic CKD patients were recruited in this cross-sectional and observational study. Montreal cognitive assessment questionnaire was applied to them to estimate global cognitive level. Peripheral and central blood pressure, augmentation index, brachial-ankle pulse wave velocity (baPWV), heart rate and P300 ERP were recorded. Biochemical analysis of the serum was also done. Appropriate statistical tests were performed to compare the differences between the variables of the two groups. Spearman’s Correlation test was performed to examine the relationship between vascular parameters and P300 ERP metrics. Results: Haemodialytic CKD patients exhibit early vascular ageing than non-haemodialytic CKD patients as evidenced by increased heart rate (P = 0.001) and higher central diastolic (P = 0.035) and peripheral diastolic blood pressure (P = 0.042). Although there was no significant difference in latency and amplitude of P300 ERP between the two groups, a significant positive association between baPWV and amplitude of P300 ERP was found. Moreover, higher serum phosphate (P = 0.021) and uric acid levels (P = 0.017) in haemodialytic patients promote vascular stiffening. Conclusion: It may be concluded that early vascular ageing in CKD patients occurs due to the interplay of multiple physiological factors, which finally perturb cerebral haemodynamics and are responsible for the cognitive impairment observed in these patients.

Preventative insecticides reduce seedling injury, but do not increase yield in Bt and non-Bt corn grown in the mid-Atlantic.

Field corn production systems rely on preventative insect management tactics, including hybrids expressing plant-incorporated protectants that are treated with neonicotinoid seed treatments and sometimes in-furrow pyrethroids. While effective seedling pest control can be crucial because of the cost of replanting, these treatments target many of the same pests and may add unnecessary costs for growers. Furthermore, seedling pests in the Mid-Atlantic tend to be sporadic, and preventative insecticides may negatively impact natural enemies. To better understand the value of common preventative tactics, we evaluated pest pressure and compared a neonicotinoid seed treatment (clothianidin) and an in-furrow pyrethroid (bifenthrin) in Bacillus thuringiensis (Bt) and non-Bt corn hybrids. In Bt hybrids, the in-furrow pyrethroid did not decrease pest injury, increase stand, or increase yield, while the neonicotinoid seed treatment decreased pest injury and increased stand but did not increase yield. In a non-Bt hybrid, both insecticides decreased pest injury, but neither increased stand or yield. Above- and below-ground pest injury was scarce throughout the study, but even in the site-year with the most extensive injury, insecticides did not result in yield gains. Implementing efficient economically and environmentally sustainable corn pest management requires a thorough understanding of the contributions of each component of the pest control system. By thoroughly exploring pest pressure in Bt and non-Bt systems, this study shows that preventative insecticide use could be scaled back in many cases, especially given the environmental and economic costs associated with them. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Nonlinear modeling and control of hydrogen generating system

ABSTRACT This work attempts to develop a nonlinear control algorithm for a Proton Exchange Membrane (PEM) electrolyzer unit working as a hydrogen generating system. Initially, the system dynamics is studied using the model equations resulting from first principle balance at the anode and cathode. The system model is split into six ancillaries viz. anode, cathode, membrane, thermal, voltage, and storage. The first principles models are simulated using MATLAB/Simulink and verified with the data available in the open literature. This work is intended to analyze the performance of an observer-based controller for the system. The originality of this work lies in the integration of PEM electrolyzer and hydrogen storage system followed by controlling the electrolyzer temperature and storage system pressure. The system is automated with a nonlinear control strategy known as globally linearizing controller (GLC). An adaptive state observer (ASO) has been formulated to estimate unknown state variables. To select the optimal parameters, optimization algorithms, namely, particle swarm optimization (PSO) and Ali Baba and forty thieves (AFT) have been used. For the comparative controller performance, the closed-loop simulation of ASO-GLC has been performed. Upon comparing the closed-loop system response, the GLC performance is found better than a well-tuned PI controller.

Transient response and analytical solution of burst phenomenon in long distance water pipeline

The rapid detection and localisation of pipe burst incidents in water pipe systems are crucial for timely repair, minimisation of leakage, and assurance of water supply security. However, previous researches have insufficiently emphasised the identification of pressure characteristics during pipe burst, failing to accurate detection and localisation of pipe burst. To address this problem, an experimental system was designed to elucidate the complete dynamic process of pipe burst pressure fluctuations. Specifically, the continuous transition from steady state to transient state and back to steady state in the hydraulic state of the system after a pipe burst event, was observed both in time and space dimensions. The effects of initial pressure and flow rate at steady state, location and size of pipe burst on pressure characteristics were carefully investigated. Subsequently, a pipe burst model considering unsteady friction effect was developed and validated through experiments. Based on the above study, analytical solution regarding pressure drop during burst events and steady-state pressure at the burst point after burst events were derived to quantify the influence laws of different parameters and validated by the pipe burst model. The obtained results are characterised by the dominance analysis so as to explore the importance ranking of different factors to the pressure drop and steady-state burst pressure in the pipeline system. The analysis solution of pressure drop indicates the following ranking of factors from high to low is: pipe/burst area ratio, initial steady-state pressure at the burst point, wave speed; while the ranking of influencing factors for steady-state burst pressure from high to low is: the boundary pressures, the location of the pipe burst, the initial steady state flow rate, and the burst outflow coefficient. The research findings can provide theoretical and practical guidance for the rapid diagnosis and quantitative analysis of burst pipes.

Bupivacaine multivesicular liposomes/meloxicam nanocrystals in a thermosensitive gel adapted to the "microenvironment" for long-term analgesia.

Current analgesics on the market exhibit a short duration of action and induce the production of inflammatory factors in tissues damaged by surgical procedures. Inflammatory factor production can create acidic environments, limiting drug delivery. In this study, we developed a novel injectable formulation comprising bupivacaine multivesicular liposomes of high osmotic pressure (H-MVL) and meloxicam nanocrystals (MLX) in a thermosensitive gel (H-MVL/MLX@GEL) adapted to the microenvironment for long-term postoperative analgesia. To achieve formulation stability, H-MVL were prepared by regulating the osmotic pressure of the gel system. Moreover, the inclusion of MLX serves to not only attenuate local inflammatory factors, regulating the acidic microenvironment, but also to prolong the duration of action of meloxicam (MEL). The increased absorption of bupivacaine (BUP) and the prolongation of the half-life of BUP release in H-MVL/MLX@GEL were demonstrated through pharmacokinetic experiments. Sciatic nerve block models and hot plate analgesia tests demonstrated that H-MVL/MLX@GEL effectively alleviated pain for at least five days. The immunohistochemical results showed that the addition of MLX reduced the production of the local inflammatory factors interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α), thereby improving the analgesic effect by regulating the local acidic environment and alleviating local irritation.

Threads That Become Tendrils

The settler-state of Canada continues to reconcile with the genocide of the original Indigenous custodians of the lands on which we operate, alongside the underserving and discriminating against racialized, black, disabled, and LGBTQ2+ peoples all while navigating a climate crisis, the proliferation of equity, diversity, and inclusion (EDI) nomenclature and plans permeates every social and financial sector. EDI initiatives, while called many names throughout history such as social inclusion and affirmative action, experienced a rise in creation in 2020 because of public outcries for the acknowledgement of systemic racial injustice and pressure to address this ongoing form of violence. Canada’s arts and culture sector is not immune from this scrutiny. Having a long history of engaging in social services, the arts and culture sector is often tasked with “fixing” issues when funding is cut to education, health, and community programs, yet arts institutions are not equipped to do this. This paper follows one resident researcher’s journey as they were tasked with developing an arts civic impact framework suggesting equity practices in the arts. The study used a mixed-methods approach, drawing from the walking interview, reverse photo-elicitation, feminist manifestos and research-creation to bring cultural workers across the country together to develop an accessible tool to carefully engage in equity practices within the sector. As a critique and response to flat and prescriptive EDI plans, what was created based on this cross-country collaboration was a non-linear, spiraling framework existing online that arts organizations can make use of and adapt based on their circumstances. Weaving together a historical account of arts administration, Western managerialism, and the EDI in the arts sector, this article responds to the research question: How can access to the arts and culture sector from coast-to-coast-to-coast be more equitable?

Headache in infections.

This review explores the phenomenology, pathogenesis, and nosology of headaches associated with infections, an often-overlooked yet clinically significant symptom. With the increasing recognition of secondary headaches in infections, understanding their clinical patterns, mechanisms, and classifications is crucial for accurate diagnosis and management. Headaches in infections are ubiquitous but vary in presentation, severity, and underlying mechanisms depending on the causative pathogen. Elevated intracranial pressure, meningeal irritation, and activation of the trigeminovascular system are key contributors to headache generation, which varies depending on each pathogen. Pathogen-specific predilection for one of these mechanisms may subtly alter the clinical phenotype of the headache, which can be used to guide management. Emerging evidence highlights postinfectious headache syndromes, particularly following bacterial meningitis and SARS-CoV-2 infection, underscoring the need for long-term follow-up in these patients. The diverse presentations of infection-related headaches necessitate a systematic approach to evaluation and management. While the pathophysiology is complex and multifaceted, understanding these mechanisms aids in differentiating primary headaches from those secondary to infections.

Molecular Dynamics Study of Carbon Dioxide Gas Within Ice XVII Structure

We conducted a molecular dynamics study on CO2 hydrate within the ice XVII structure to examine the molecular diffusion of CO2 molecules, as it is essential to the hydrate potential as a carbon capture. The simulated CO2 hydrate system used 324 water molecules and 90 CO2 molecules. We used the TIP4P/Ice model for water molecules, and the CO2 molecules were treated as united atom. The simulations were carried out at 273,15 K under various pressures of 200 MPa, 500 MPa, and 1000 MPa for 1,50 ns, with a step size of 1 fs. The results showed that the CO2 molecules were confined and freely moved inside the cage-like chiral tube along the c-axis of the ice XVII structure. No significant inter-cage hopping was observed during the evolution of all simulated systems. The diffusion coefficient values for CO2 molecules within the ice XVII structure were 5.03 × 10-8 cm2s-1, 2.45 × 10-8 cm2s-1, and 8.86 × 10-8 cm2s-1 for the respective pressure variations of 200 MPa, 500 MPa, and 1000 MPa, resulting in an inverse proportional with the system's pressure. A higher diffusion coefficient facilitates a faster the mass transfer and adsorption rate of CO2 in formation build up of the CO2 hydrate system.

Conceptual and ethical considerations in invasion science

Abstract Invasion science addresses interconnected ecological, economic, and social challenges posed by the introduction of nonnative species. Therefore, invasion scientists have to consider and reconcile interdisciplinary needs while addressing the potential implications of their findings. Navigating diverse disciplines, including environmental sciences, ecology, economics, and the humanities, invasion scientists seek to arrive at informed decisions on invasion risk, impact, and management. Individual biases, uncertainties, and systemic pressures influence the ability to maintain objectivity and resist pressures that might otherwise distort their findings or applications. In the present commentary, we examine conceptual and ethical dilemmas within the field of invasion science, particularly reputational and the risks of the discipline perpetuating its own relevance by framing invasions as insurmountable challenges. In the discussion, we highlight how incentive structures, biased assessments and framing, and conflicts of interest may compromise the discipline's integrity. We also explore questions surrounding human responsibility to animal welfare and highlight ethical conundrums in the management of invasive species.

‘You Can Really See the Pain in Their Eyes’: Stressors and Supports Affecting the Well-being of Homelessness Services Staff in Ireland During COVID-19

Despite their crucial roles, the well-being narratives of those working in homelessness services have frequently been overlooked in research and policy. This paper addresses that gap, presenting qualitative evidence from interviews with homelessness service workers in Cork, Ireland, during 2021 and 2022. We explore the multidimensional, layered character of service staff members’ well-being narratives, showing they are intimately connected to relationships with their own families, commitment to service users, fears about COVID-19, and their motivation to the social mission of their work: to support vulnerable people with multiple, interlinking needs. Our data reveals that stressors encountered in pre-COVID times, relating to burnout, emotional labour, inter-agency working, and career progression, were exacerbated due to government restrictions and new challenges encountered by service users. We focus on the period covering pandemic-related lockdowns in 2020 and 2021, and the immediate aftermath, to consider how those delivering crucial services coped, the informal and formal support they accessed, and the value of this support in their lives. Significantly, our analysis reflects upon the longer-term implications of these findings, contextualised against the backdrop of the housing crisis in Ireland, changing demographics of persons accessing homelessness services, and increased systemic and social pressures.

Understanding energy cultures of space heating in Aotearoa New Zealand: a desktop review of slow ground source heat pump uptake

ABSTRACT This paper examines the slow adoption of geothermal Ground Source Heat Pump (GSHP) technology in New Zealand amid the urgent need for sustainable energy solutions in the face of the climate crisis. Internationally, GSHPs offer many environmental, social and economic benefits across residential and commercial sectors. However, despite the global installation of approximately 6.5 million GSHP units, New Zealand has seen limited implementation, with 130 known installations. Using the Energy Cultures Framework, this paper conducts a scoping literature review to analyse the dominant socio-economic barriers to GSHP uptake including energy hardship, prioritisation of immediate savings over long-term cost-saving benefits, low public awareness and financial risk aversion towards new sustainable energy solutions. This paper recommends further industry engagement and primary research to understand New Zealand's heating norms and attitudes towards GSHPs. Additionally, this paper advocates for future cost–benefit analysis to evaluate GSHP's potential contributions to decarbonisation objectives, alleviating electricity system pressures, and mitigating energy hardship. Such future analysis may serve as a catalyst for stimulating future uptake of GSHP technology.

Estimating the impact of school closures on the COVID-19 dynamics in 74 countries: A modelling analysis.

School closures have been a prominent component of the global Coronavirus Disease 2019 (COVID-19) response. However, their effect on viral transmission, COVID-19 mortality and health care system pressure remains incompletely understood, as traditional observational studies fall short in assessing such population-level impacts. We used a mathematical model to simulate the COVID-19 epidemics of 74 countries, incorporating observed data from 2020 to 2022 and historical school closure timelines. We then simulated a counterfactual scenario, assuming that schools remained open throughout the study period. We compared the simulated epidemics in terms of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infections, deaths, and hospital occupancy pressure. We estimated that school closures achieved moderate to significant burden reductions in most settings over the period 2020 to 2022. They reduced peak hospital occupancy pressure in nearly all countries, with 72 out of 74 countries (97%) showing a positive median estimated effect, and median estimated effect ranging from reducing peak hospital occupancy pressure by 89% in Brazil to increasing it by 19% in Indonesia. The median estimated effect of school closures on COVID-19 deaths ranged from a 73% reduction in Thailand to a 7% increase in the United Kingdom. We estimated that school closures may have increased overall COVID-19 mortality (based on median estimates) in 9 countries (12%), including several European nations and Indonesia. This is attributed to changes in population-level immunity dynamics, leading to a concentration of the epidemic during the Delta variant period, alongside an upward shift in the age distribution of infections. While our estimates were associated with significant uncertainty, our sensitivity analyses exploring the impact of social mixing assumptions revealed robustness in our country-specific conclusions. The main study limitations include the fact that analyses were conducted at the national level, whereas school closure policies often varied by region. Furthermore, some regions, including Africa, were underrepresented due to insufficient data informing the model. Our analysis revealed nuanced effects of school closures on COVID-19 dynamics, with reductions in COVID-19 impacts in most countries but negative epidemiological effects in a few others. We identified critical mechanisms for consideration in future policy decisions, highlighting the unpredictable nature of emerging variants and potential shifts in infection demographics associated with school closures.

Mortality Patterns in Pediatric Pulmonary Vein Stenosis: Insights Into Right Ventricular Systolic Pressure Associations.

Pulmonary vein stenosis in children is associated with a poor prognosis. However, the cause and risk factors for mortality remain uncertain. This retrospective, single-center study identified children with primary and secondary pulmonary vein stenosis through a cardiac catheterization database. Kaplan-Meier analysis, log-rank tests, and Cox regression analysis were performed to assess outcome and identify significant predictors of mortality. Among 56 children with pulmonary vein stenosis (33 male children, 59%), 20 (36%) died at a median age of 10 months (interquartile range,4-24 months). All patients underwent cardiac catheterization, with 45 (80%) undergoing at least 1 interventional procedure. Causes of death included multiorgan failure (35%), progressive respiratory failure (20%), and sudden cardiac death (15%). Prematurity, chronic lung disease, a genetic syndrome, or the number of affected pulmonary veins did not significantly correlate with mortality. However, right ventricular (RV) systolic pressure greater than half systemic pressure was associated with mortality (hazard ratio [HR], 5.5 [95% CI, 2.2-14.1]; P<0.001). The final predictive model for mortality included RV systolic pressure greater than half systemic pressure (HR, 4.0 [95% CI, 1.6-10.4]; P=0.004), moderately or severely diminished RV systolic function (HR, 3.6 [95% CI, 1.1-11.5]; P=0.032), and the presence of congenital heart disease (HR, 2.4 [95% CI, 0.9-6.7]; P=0.084). This report is the first to indicate that RV systolic pressure and RV dysfunction are significant independent predictors of mortality in children with pulmonary vein stenosis. A greater understanding of mortality in this population is necessary, particularly in those with RV systolic pressure less than half systemic.

A new tube chamber system for evaluation of anterior chamber pressure during phacoemulsification tested in porcine eyes.

To measure the optimal anterior chamber pressure (ACP) for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye. The 20-gauge and 21-gauge straight tips with yellow and orange sleeves, respectively, were covered by a test chamber combined with a pressure sensor for measuring ACP. This was measured for 20s from 10s after starting aspiration in the linear mode using vacuum levels of 200 and 150 mm Hg with a 20-gauge tip, and 300 and 250 mm Hg with a 21-gauge tip. Using a porcine eye, a pressure sensor fixed with a 0.9 mm corneal incision measured ACP. For the posterior capsule contact assay, porcine eyes were treated as described above, and the ultrasonic needle tip was held at the height of the iris and aspirated for 30s in linear mode at a vacuum of 200 and 150 mm Hg for the 20-gauge tip, and 300 and 250 mm Hg for the 21-gauge tip. The bottle height at which the posterior capsule accidentally contacted the ultrasonic tip was recorded, and the estimated ACP was calculated. The internal pressure of the new tube chamber system and ACP from the porcine eye closely matched proportional changes at vacuum levels of 200 and 150 mm Hg with 20-gauge tips. Similarly, proportional changes at vacuum levels of 300 and 250 mm Hg with the 21-gauge tip were nearly equal. The bottle height at which the posterior capsule contacted with the tip and estimated ACP were 57.5±12.6 cm (20.2±7.9 mm Hg) at 200 mm Hg with a 20-gauge tip, 35.0±10.0 cm (16.6±6.3 mm Hg) at 150 mm Hg with a 20-gauge tip, 47.5±12.6 cm (18.7±8.7 mm Hg) at 300 mm Hg with a 21-gauge tip, and 32.5±5.0 cm (15.7±3.5 mm Hg) at 250 mm Hg with a 21-gauge tip. A comprehensive understanding of this chamber system's characteristics and usage can resolve anterior chamber instability caused by changing preoperative settings on the phaco machine.

The Generation Load Aggregator Participates in the Electricity Purchase and Sale Strategy of the Electric Energy–Peak Shaving Market

To facilitate the participation of small- and medium-sized customer-side resources into the electricity market, with the aim of optimizing the allocation of electricity resources, this paper proposes the participation of small- and medium-sized adjustable resources in the electricity market in the form of generation load aggregators. Considering the coupling role of the electric energy market and the peaking auxiliary service market, a joint model of generation load aggregators that participate in the electric energy–peak shaving market is constructed. Comparing the model solution with those of the control group, the peak-to-valley difference of 10.5 MW is much lower than that of the control group, which is 16.54 MW. Compared with the control group, the profit was increased by USD 2.6 thousand, or 6.06%. It can be seen that the model proposed in this paper can reduce the peak and valley pressure as well as the control pressure of the power system from the load side. By participating in the peak shaving market, the transferable loads within the generation load aggregators can give full play to its adjustable characteristics, thereby reducing the cost of electricity consumption and increasing its profit, and providing a certain theoretical basis for the electricity market management to design the rules for adjustable users to enter the electricity market.

A potential hydrogen isotope storage material Zr2Fe: deep exploration on phase transition behaviors and disproportionation mechanism

Tritium, a radioactive isotope of hydrogen, is exceptionally rare and valuable. The safe storage, controlled release and efficient capture of tritium are subject to focused research in the International Thermonuclear Experimental Reactor. However, the application of an efficient tritium-getter material remains a critical challenge. Zr2Fe alloys exhibit a strong ability to absorb low-concentration hydrogen isotopes, but their practicability suffers from disproportionation reaction. Yet, the essential de-/hydrogenation performances and disproportionation mechanism of Zr2Fe are inconclusive. Here, we designed a comprehensive series of measurements that demonstrate the ultra-low hydrogenation equilibrium pressure (2.68 × 10-8 Pa at 25 °C) and unique hydrogen-interacted phase transitions in Zr2Fe-H systems. Further kinetic and thermodynamic analyses reveal the causative reasons for disproportionation and determine the triggering temperature of the disproportionation reaction to be 375 °C in static hydrogen environments. Utilizing inversion of the Van't Hoff equation, higher-temperature hydrogen absorption models of Zr2Fe are developed, supporting a solution to the inaccuracy and inseparability of the general de-/hydrogenation and disproportionation, thereby verifying the unique disproportionation route (Zr2Fe/Zr2FeHx + H2 → ZrFe2 + ZrH2). Combined with the density functional theory (DFT) calculations, the de-/hydrogenation and disproportionation mechanisms and their interrelation can be explained in depth. This work supports the exploration and modification of the Zr2Fe-H and other metal hydride storage systems in future studies.

AI-Assisted Forecasting of a Mitigated Multiple Steam Generator Tube Rupture Scenario in a Typical Nuclear Power Plant

This study is focused on developing a machine learning (ML) meta-model to predict the progression of a multiple steam generator tube rupture (MSGTR) accident in the APR1400 reactor. The accident was simulated using the thermal–hydraulic code RELAP5/SCDAPSIM/MOD3.4. The model incorporates a mitigation strategy executed through operator interventions. Following this, uncertainty quantification employing the Best Estimate Plus Uncertainty (BEPU) methodology was undertaken by coupling RELAP5/SCDAPSIM/MOD3.4 with the statistical software, DAKOTA 6.14.0. The analysis concentrated on critical safety parameters, including Reactor Coolant System (RCS) pressure and temperature, as well as reactor vessel upper head (RVUH) void fraction. These simulations generated a comprehensive dataset, which served as the foundation for training three ML architectures: Gated Recurrent Unit (GRU), Long Short-Term Memory (LSTM), and Convolutional LSTM (CNN+LSTM). Among these models, the CNN+LSTM hybrid configuration demonstrated superior performance, excelling in both predictive accuracy and computational efficiency. To bolster the model’s transparency and interpretability, Integrated Gradients (IGs)—an advanced Explainable AI (XAI) technique—was applied, elucidating the contribution of input features to the model’s predictions and enhancing its trustworthiness.

Association between cerebral oxygenation and usual parameters of cerebral perfusion in critically ill patients with acute brain injury.

In patients with acute brain injury (ABI), optimizing cerebral perfusion parameters relies on multimodal monitoring. This include data from systemic monitoring-mean arterial pressure (MAP), arterial carbon dioxide tension (PaCO2), arterial oxygen saturation (SaO2), hemoglobin levels (Hb), and temperature-as well as neurological monitoring-intracranial pressure (ICP), cerebral perfusion pressure (CPP), and transcranial Doppler (TCD) velocities. We hypothesized that these parameters alone were not sufficient to assess the risk of cerebral ischemia. We conducted a retrospective, single-center study of patients admitted in our ICU between 2015 and 2021. Patients with ABI and multimodal neuromonitoring were included. ABI included traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), intracranial hemorrhage and ischemic stroke. The relationship between jugular venous oxygen saturation (SjvO2) and cerebral perfusion parameters was analyzed. Patients were categorized into two groups based on SjvO2, with a threshold of 60% used to define cerebral ischemia. We compared the parameters used to optimize cerebral perfusion between groups and their diagnosis accuracy for cerebral ischemia was evaluated. Univariable and multivariable analyses were performed to assess the association between the guideline-recommended therapeutic targets and the risk of cerebral ischemia. 601 evaluations from 96 patients with simultaneous ICP, SjvO2 and TCD were analyzed. Poor relationships were found between SjvO2 and the parameters of cerebral perfusion. TCD flow velocities and PaCO2 were lower in the cerebral ischemia group while MAP, ICP and CPP were not different between groups. Most ischemic episodes occurred despite ICP < 22 mmHg and CPP ≥ 60 mmHg. For the diagnosis of cerebral ischemia, only TCD parameters and PaCO2 were associated with an area under the curve (AUC) > 0.5 but with a low accuracy. In multivariable analysis, the only guideline-recommended therapeutic target associated with a reduction of cerebral ischemia was a diastolic flow velocity (FV) > 20 cm.s-1.