Deep learning approaches to recover the plasma current density profile from the safety factor based on Grad–Shafranov solutions across multiple tokamaks

Many magnetohydrodynamic stability analyses require generation of a set of equilibria with a fixed safety factor q-profile while varying other plasma parameters.A neural network(NN)-based approach is investigated that facilitates such a process.Both multilayer perceptron(MLP)-based NN and convolutional neural network(CNN)models are trained to map the q-profile to the plasma current density J-profile,and vice versa,while satisfying the Grad–Shafranov radial force balance constraint.When the initial target models are trained,using a database of semianalytically constructed numerical equilibria,an initial CNN with one convolutional layer is found to perform better than an initial MLP model.In particular,a trained initial CNN model can also predict the q-or J-profile for experimental tokamak equilibria.The performance of both initial target models is further improved by fine-tuning the training database,i.e.by adding realistic experimental equilibria with Gaussian noise.The fine-tuned target models,referred to as fine-tuned MLP and fine-tuned CNN,well reproduce the target q-or J-profile across multiple tokamak devices.As an important application,these NN-based equilibrium profile convertors can be utilized to provide a good initial guess for iterative equilibrium solvers,where the desired input quantity is the safety factor instead of the plasma current density.

Optimizing slope safety factor prediction via stacking using sparrow search algorithm for multi-layer machine learning regression models

The safety factor is a crucial quantitative index for evaluating slope stability.However,the traditional calculation methods suffer from unreasonable assumptions,complex soil composition,and inadequate consideration of the influencing factors,leading to large errors in their calculations.Therefore,a stacking ensemble learning model(stacking-SSAOP)based on multi-layer regression algorithm fusion and optimized by the sparrow search algorithm is proposed for predicting the slope safety factor.In this method,the density,cohesion,friction angle,slope angle,slope height,and pore pressure ratio are selected as characteristic parameters from the 210 sets of established slope sample data.Random Forest,Extra Trees,AdaBoost,Bagging,and Support Vector regression are used as the base model(inner loop)to construct the first-level regression algorithm layer,and XGBoost is used as the meta-model(outer loop)to construct the second-level regression algorithm layer and complete the construction of the stacked learning model for improving the model prediction accuracy.The sparrow search algorithm is used to optimize the hyperparameters of the above six regression models and correct the over-and underfitting problems of the single regression model to further improve the prediction accuracy.The mean square error(MSE)of the predicted and true values and the fitting of the data are compared and analyzed.The MSE of the stacking-SSAOP model was found to be smaller than that of the single regression model(MSE=0.03917).Therefore,the former has a higher prediction accuracy and better data fitting.This study innovatively applies the sparrow search algorithm to predict the slope safety factor,showcasing its advantages over traditional methods.Additionally,our proposed stacking-SSAOP model integrates multiple regression algorithms to enhance prediction accuracy.This model not only refines the prediction accuracy of the slope safety factor but also offers a fresh approach to handling the intricate soil composition and other influencing factors,making it a precise and reliable method for slope stability evaluation.This research holds importance for the modernization and digitalization of slope safety assessments.

Efficacy and safety of anti-vascular endothelial growth factor agents on corneal neovascularization: A meta-analysis

BACKGROUND Corneal neovascularization(CoNV)is the second major cause of blindness.Vascular endothelial growth factor(VEGF)inhibitors,e.g.,bevacizumab,have been used to prevent CoNV.AIM We conducted an updated systematic review and meta-analysis of clinical trials to examine the efficacy and safety of anti-VEGF in CoNV.METHODS A literature search was conducted using three electronic databases.Mean difference(MD),standard mean difference(SMD),and relative risk(RR)are used to estimate the effect size.RESULTS Nine randomized controlled and three non-randomized trials were obtained.The pooled results demonstrated a significant reduction of CoNV area/Length(SMD=-1.17,95%CI:-1.58 to-0.75),best corrected visual acuity(MD=-0.54,95%CI:-0.91 to-0.17),and graft rejection(RR=0.44,95%CI:0.24 to 0.8)and failure(RR=0.39,95%CI:0.19 to 0.78)rates in the anti-VEGF group than the placebo group.A non-significant reduction of the epithelial defect was also observed in the bevacizumab group compared with the placebo(RR=0.56,95%CI:0.30 to 1.06).Compared with a placebo,the unsynthesizable trials also support that bevacizumab improves visual acuity,CoNV,graft rejection,and failure rates.Trials reporting other comparisons revealed the superiority of combined remedy with bevacizumab compared to other treatments in reducing CoNV.CONCLUSION Anti-VEGF agents,mainly bevacizumab,are an effective and safe treatment for CoNV of all causes and prevent corneal graft rejection and failure in corneal transplantation.

Factors associated with the incidence of patient falls in hospitals:A scoping review

When a patient falls within a hospital setting,there is a significant increase in the risk of severe injury or health complications.Recognizing factors associated with such falls is crucial to mitigate their impact on patient safety.This review seeks to analyze the factors contributing to patient falls in hospitals.The main goal is to enhance our understanding of the reasons behind these falls,enabling hospitals to devise more effective prevention strategies.This study reviewed literature published from 2013 to 2022,using the Arksey and O’Malley methodology for a scoping review.The research literature was searched from seven databases,namely,PubMed,ScienceDirect,Wiley Library,Garuda,Global Index Medicus,Emerald Insight,and Google Scholar.The inclusion criteria comprised both qualitative and quantitative primary and secondary data studies centered on hospitalized patients.Out of the 893 studies analyzed,23 met the criteria and were included in this review.Although there is not an abundance of relevant literature,this review identified several factors associated with falls in hospitals.These encompass environmental,patient,staff,and medical factors.This study offers valuable insights for hospitals and medical personnel aiming to enhance fall prevention practices.Effective prevention efforts should prioritize early identification of patient risk factors,enhancement of the care environment,thorough training for care staff,and vigilant supervision of high-risk patients.By comprehending the factors that contribute to patient falls,hospitals can bolster patient safety and mitigate the adverse effects of falls within the health-care setting.

Assessment of Axial Power Peaking Factors in GHARR-1 LEU Core: A Decadal Simulation Analysis

This study aims to thoroughly investigate the axial power peaking factors (PPF) within the low-enriched uranium (LEU) core of the Ghana Research Reactor-1 (GHARR-1). This study uses advanced simulation tools, like the MCNPX code for analysing neutron behavior and the PARET/ANL code for understanding power variations, to get a clearer picture of the reactor’s performance. The analysis covers the initial six years of GHARR-1’s operation and includes projections for its whole 60-year lifespan. We closely observed the patterns of both the highest and average PPFs at 21 axial nodes, with measurements taken every ten years. The findings of this study reveal important patterns in power distribution within the core, which are essential for improving the safety regulations and fuel management techniques of the reactor. We provide a meticulous approach, extensive data, and an analysis of the findings, highlighting the significance of continuous monitoring and analysis for proactive management of nuclear reactors. The findings of this study not only enhance our comprehension of nuclear reactor safety but also carry significant ramifications for sustainable energy progress in Ghana and the wider global context. Nuclear engineering is essential in tackling global concerns, such as the demand for clean and dependable energy sources. Research on optimising nuclear reactors, particularly in terms of safety and efficiency, is crucial for the ongoing advancement and acceptance of nuclear energy.

Impact of Improving Design Factor over 0.72 on the Safety and Reliability of Gas Pipelines and Feasibility Justification

Many years experience of the operation of high stress (>72% specified minimum yield strength, SMYS) gas pipelines and statistical analysis results of pipeline incidents showed that the operating pipelines at stress levels over 72% SMYS have not presented problems in USA and Canada, and design factor does not control incidents or the safety of pipelines. Enhancing pipeline safety management level is most important for decreasing incident rate. The application history of higher design factors in the U.S and Canada was reviewed. And the effect of higher factors to the critical flaw size, puncture resistance, change of reliability with time, risk level and the arrest toughness requirements of pipeline were analyzed here. The comparison of pipeline failure rates and risk levels between two design factors (0.72 and 0.8) has shown that a change in design factor from 0.72 to 0.8 would bring little effect on failure rates and risk levels. On the basis of the analysis result, the application feasibility of design factor of 0.8 in China was discussed and the related suggestions were proposed. When an operator wishes to apply design factor 0.8 to gas pipeline, the following process is recommended: stress level of line pipe hydro test should be up to 100% SMYS, reliability and risk assessment at the design feasibility or conceptual stage should be conducted, Charpy impact energy should meet the need of pipeline crack arrest; and establish and execute risk based integrity management plan. The technology of pipeline steel metallurgy, line pipe fabrication and pipeline construction, and line pipe quality control level in China achieved tremendous progresses, and line pipe product standards and property indexes have come up to international advanced level. Furthermore, pipeline safety management has improved greatly in China. Consequently, the research for the feasibility of application of design factor of 0.8 in China has fundamental basis.

Addressing Human Factors in Burnout and the Delivery of Healthcare: Quality & Safety Imperative of the Quadruple Aim

Human factors in the delivery of service are considered in many occupations of high impact on others such as airline industry and nuclear power industry, but not sufficiently in healthcare delivery. A common administrative framework of healthcare involves focus upon costs, quality and patient satisfaction (The Triple Aim). Many industries which support healthcare and healthcare administrators do not have firsthand knowledge of the complexities in delivering care. As a result, the experience and human factors of providing care are often overlooked at high level decision-making unless incorporated into the healthcare delivery framework, proposed as the fourth aim of The Quadruple Aim framework. Research is pointing to consequent negative effects on quality, safety, joy, meaning and sustainability of healthcare practice. High acute occupational stress and chronic occupational stress can cause direct and indirect effects on safety and quality of care. The biological, psychological and social consequences of burnout from excessive acute and chronic occupational stress are more of a threat to healthcare than commonly acknowledged. Patient safety, quality of care and clinician well-being are inextricably linked. This report will describe the process of transition from The Triple Aim to The Quadruple Aim administrative framework of healthcare delivery at the University of Rochester Medical Center. Developing the fourth aim of improving the experience of providing care, had high acceptability and aligned with other health system goals of optimization of safety, quality, and performance by applying a human factors/ergonomic (HFE) framework that considers human capabilities and human limitations. The goal of HFE is to fit the healthcare system to the human instead of the human to the healthcare system. Concepts include removal of extraneous cognitive load, using clinician neural resource (brain power) optimally for highest order decision making in patient care. An integrative model of patient safety and clinician wellbeing is a product of this effort.

Factor of safety of strain-softening slopes

Stability analysis of strain-softening slopes is carried out using the shear strength reduction method and Mohr-Coulomb model with degrading cohesion and friction angle.The e ffect of strain-softening behavior on the slope factor of safety is investigated by performing a series of analyses for various slope geometries and strength properties.Stability charts and equations are developed to estimate the factor of safety of strain-softe ning slopes from the results of traditional stability analysis based on perfectly-plastic behavior.Two example applications including an open pit mine in weak rock and clay shale slope with daylighting bedding planes are presented.The results of limit equilibrium analysis and shear strength reduction method with perfectly-plastic models were in close agreement.Using perfectly-plastic models with peak strength properties led to overly optimistic results while adopting residual strength properties gave excessively conservative outcomes.The shear strength reduction method with a strain-softening model gave realistic factors of safety while accounting for the process of strength degradation.

The stability safety factor calibration based on the reliability index

When the bridge structure stability safety factor of the first type is 4, the research that whether the structure reliability index will reach target reliability index under the more-likely-to-happen collapse situation of the second type is necessary. The stability calculations of the first and the second type are made respectively for single layer and single span rigid frame bridge. Based on the critical load obtained from the stability calculation of the first type, the stability safety factor of the first type is taken as 4, and the first order reliability method is used to program and calculate the reliability index. Then, the load effect under the stability reliability index cal- culation of the first type and the critical load of the second type are employed to calculate the reliability index of the second type. The evaluation of structure stability safety factor is discussed according to reliability index. Based on the discussion above, parameter analysis of the stable critical loads of two types is made, and the in- fluence of critical load change on reliability index is researched. The result shows that stability analysis should identify collapse state; when the stability safety factor of the first type is 4, but the structure has the collapse of the second type, the reliability index cannot be ensured to reach the target reliability index under certain condi- tions.

Promoting Clinician Well-Being and Patient Safety Using Human Factors Science: Reducing Unnecessary Occupational Stress

Our healthcare delivery system has accumulated complexity of payment, regulation systems, expectations and requirements. Often these are not designed to align with clinical thinking process flow of patient care. As a result, clinicians are utilizing enormous mental (cognitive) resource to comply with these complexities, over and above the baseline mental effort required to give good care to the patient. Recent studies suggest a significant number of physicians, advanced practice providers and nurses no longer want to stay in healthcare due to difficult work expectations and conditions that have become unreasonable. Technology has benefitted healthcare delivery, but also is a conduit of many expectations that have been grafted upon clinician workloads, exceeding the resources provided to accomplish them. Cognitive load is a measure of mental effort and is divided into Intrinsic, Germane and Extraneous Cognitive Load. Extraneous Cognitive Load (ECL) is what is not necessary and can be removed by better design. High cognitive load is associated with increased risk of both medical error and clinician burnout. Chronic high level occupational stress occurs from dealing with this job/resource imbalance and is showing serious personal health impact upon clinicians and the quality of the work they can provide for patients. Since organizational systems have become more complex, leadership methods, clinician wellbeing and patient safety efforts need to adjust to adapt and succeed. Safety efforts have tended to predominantly follow methods of a few decades ago with predominant focus upon how things go wrong (Safety I) but are now being encouraged to include more of the study of how things go right (Safety II). Human Factors/Ergonomics (HFE) science has been used in many industries to preserve worker wellbeing and improve system performance. Patient safety is a product of good system performance. HFE science helps inform mechanisms behind Safety I and II approach. HFE concepts augment existing burnout and safety interventions by providing a conceptual roadmap to follow that can inform how to improve the multiple human/technology, human/system, and human/work environment interfaces that comprise healthcare delivery. Healthcare leaders, by their influence over culture, resource allocation, and implementation of requirements and workflows are uniquely poised to be effective mitigators of the conditions leading to clinician burnout and latent medical error. Basic knowledge of HFE science is a strategic advantage to leaders and individuals tasked with achieving quality of care, controlling costs, and improving the experiences of receiving and providing care.

High-Risk Rural Road Safety Study and Determining the Crash-Reduction Factors for High-Risk Rural-Road Usage

More than 32,000 motorists are killed on U.S. roads and streets annually, and approximately 54% of the accidents occur on rural roads. In an attempt to address and reduce these fatalities, the current transportation act, the Safe, Accountable, Flexible, Efficient Transportation Equality Act: A Legacy for Users (SAFETY-LU), elevated the Highway Safety Improvement Program (HSIP) to a core program and included a $90,000,000 High-Risk Rural Road Program (HRRRP) to address and significantly reduce traffic fatalities and incapacitating injuries on rural major or minor collectors, and/or rural local roads. While there were many challenges to properly implement the HRRRP in counties, this study provided important information that was needed to identify the predominant crash types on HRRRP-eligible roads and compiled a list of countermeasures for the predominant crash types that were identified on Kansas’ high-risk rural roads. For the gathered countermeasures, crash reduction factors (CRFs) were also provided from the literature review, and their values were validated by conducting interviews with Kansas county engineers/officials. This study provided valuable information for the county engineers and local government officials while they worked on improving the safety of high-risk rural roads using HRRRP funds.

Residual fatigue strength of 48MnV crankshaft based on safety factor

Residual fatigue strength of 48MnV crankshaft was studied and analyzed based on safety factor. Three different status crankshafts were used to the hop-up tests, which maintain new after 500h hop-up tests and after 1000h hop-up tests. Then, crankshafts were cut into unit cranks. The unit cranks were used to do endurance bending tests to get the residual fatigue strength. Finally, the results were analyzed based on safety factor. The results show that safety factor of crankshaft descends a little with the increase of the running time, and the residual safety factor is still much bigger than the endurable safety factor. Furthermore, after the crankshaft accomplishes a full life cycle, the residual fatigue strength of the crankshaft is enough to remanufacture and fulfill the next life cycle.

Three-dimensional stability of landslides based on local safety factor

Unlike the limit equilibrium method(LEM), with which only the global safety factor of the landslide can be calculated, a local safety factor(LSF) method is proposed to evaluate the stability of different sections of a landslide in this paper. Based on three-dimensional(3D) numerical simulation results, the local safety factor is defined as the ratio of the shear strength of the soil at an element on the slip zone to the shear stress parallel to the sliding direction at that element. The global safety factor of the landslide is defined as the weighted average of all local safety factors based on the area of the slip surface. Some example analyses show that the results computed by the LSF method agree well with those calculated by the General Limit Equilibrium(GLE) method in two-dimensional(2D) models and the distribution of the LSF in the 3D slip zone is consistent with that indicated by the observed deformation pattern of an actual landslide in China.

Toroidicity Dependence of Tokamak Edge Safety Factor and Shear

Using a simple analytical model equilibrium, the dependence of tokamak edge safety factor qedge which can be understood as qa for a limiter device or 595 for a divertor device, and the shear value are calculated and compared with the ITRE-recommended formula. This dependence relation is useful in designing the medium and small aspect ratio tokamaks and reactors.

Risk Factors for Anesthesia-Related Airway Patient Safety Incidents:A Single-Center Retrospective Case-Control Analysis from 2009 to 2022

Objective Airway-related patient safety incident(PSI)has always been the top concern of anesthesiologists because this type of incidents could severely threaten patient safety if not treated immediately and properly.This study intends to reveal the composition,prognosis,and to identify risk factors for airway related incidents reported by anesthesiologists.Methods All airway related PSIs reported by anesthesiologists in a Chinese academic hospital between September 2009 and May 2022 were collected from the PSI reporting system.Patients with airway incidents reported were matched 1:1 with controls based on sex and type of surgery.Univariable and multivariable analysis were performed to find risk factors associated with airway incident occurrence,and to evaluate influence of airway PSIs on patient prognosis.Results Among 1,038 PSIs voluntarily reported by anesthesiologists during the study period,281 cases(27.1%)were airway-related incidents,with an overall reporting incidence of 4.74 per 10,000 among 592,884 anesthesia care episodes.Only ASA physical status was found to be significant independent predictor of these airway PSIs(P=0.020).Patients with airway PSIs reported had longer extubation time(0.72±1.56 d vs.0.16±0.77 d,95%CI:0.29 to 0.82,P<0.001),longer ICU length of stay(LOS)(1.63±5.71 d vs.0.19±0.84 d,95%CI:0.57 to 2.32,P=0.001),longer post operative LOS(10.56±13.09 d vs.7.59±10.76 d,95%CI:0.41 to 5.53,P=0.023),and longer total in-hospital LOS(14.99±15.18 d vs.11.62±11.88 d,95%CI:0.46 to 6.27,P=0.024).Conclusions This single-center retrospective case-control study describes the composition of airway-related PSIs reported by anesthesiologists within thirteen years.Airway incidents might influence patient prognosis by elongating extubation time and LOS.Airway PSI data were worth analyzing to improve patient safety.

Hysteresis of Dam Slope Safety Factor under Water Level Fluctuations Based on the LEM Coupled with FEM Method

Water level variations have caused numerous dam slope collapse disasters around the world,illustrating the large influence of water level fluctuations on dam slopes.The required indoor tests were conducted and a numerical model of an actual earth-filled dam was constructed to investigate the influences of the water level fluctuation rate and the hysteresis of the soil-water characteristic curve(SWCC)on the stability of the upstream dam slope.The results revealed that the free surface in the dam body for the desorption SWCC during water level fluctuations was higher than that for the adsorption SWCC,which would be more evident at higher water levels.The safety factor of the upstream dam slope initially decreased and then increased for the most dangerous water level as the water level rose and fell.The water level fluctuation rate mainly influenced the initial section of the safety factor variation curve,while the SWCC hysteresis mainly affected the minimum safety factor of the water level fluctuations.The desorption SWCC is suggested for engineering design.Furthermore,a quick prediction method is proposed to estimate the safety factor of upstream dam slopes with identical structures.

Limit equilibrium method(LEM) of slope stability and calculation of comprehensive factor of safety with double strength-reduction technique

When the slope is in critical limit equilibrium(LE) state, the strength parameters have different contribution to each other on maintaining slope stability. That is to say that the strength parameters are not simultaneously reduced. Hence, the LE stress method is established to analyze the slope stability by employing the double strengthreduction(DSR) technique in this work. For calculation model of slope stability under the DSR technique, the general nonlinear Mohr–Coulomb(M–C) criterion is used to describe the shear failure of slope. Meanwhile, the average and polar diameter methods via the DSR technique are both adopted to calculate the comprehensive factor of safety(FOS) of slope. To extend the application of the polar diameter method, the original method is improved in the proposed method. After comparison and analysis on some slope examples, the proposed method's feasibility is verified. Thereafter, the stability charts of slope suitable for engineering application are drawn. Moreover, the studies show that:(1) the average method yields similar results as that of the polardiameter method;(2) compared with the traditional uniform strength-reduction(USR) technique, the slope stability obtained using the DSR techniquetends to be more unsafe; and(3) for a slope in the critical LE state, the strength parameter φ, i.e., internal friction angle, has greater contribution on the slope stability than the strength parameters c, i.e., cohesion.

Development of Safety Factors for the UT Data Analysis Method in Plant Piping

There are several thousand piping components in a nuclear power plant. These components are affected by degradation mechanisms such as FAC (Flow-Accelerated Corrosion), cavitation, flashing, and LDI (Liquid Droplet Impingement). Therefore, nuclear power plants implement inspection programs to detect and control damages caused by such mechanisms. UT (Ultrasonic Test), one of the non-destructive tests, is the most commonly used method for inspecting the integrity of piping components. According to the management plan, several hundred components, being composed of as many as 100 to 300 inspection data points, are inspected during every RFO (Re-Fueling Outage). To acquire UT data of components, a large amount of expense is incurred. It is, however, difficult to find a proper method capable of verifying the reliability of UT data prior to the wear rate evaluation. This study describes the review of UT evaluation process and the influence of UT measurement error. It is explored that SAM (Square Average Method), which was suggested as a method for reliability analysis in the previous study, is found to be suitable for the determination whether the measured thickness is acceptable or not. And, safety factors are proposed herein through the statistical analysis taking into account the components’ type.

Method of Calculating the Safety Factor Profile on the HT-7 Tokamak

A method of calculating the safety profile on the HT-7 tokamak has been described in this paper. It is derived from Maxwell's equations, among which we-mainly use .two of them: one is the magnetic field diffusion equation, and the other is Ampere's Law. This method can be also used to evaluate the safety factor on other devices with a circular cross sections. It is helpful to the study of the plasma MHD behavior on the HT-7 tokamak.

Human Factor in Flight Safety

A chief goal of the launcher design philosophy is to build launchers offering operational efficiency and not that can be flown safely.Moreover,launch operator focuses the mission design on mission success criteria for the payload and often mitigates launch risks.These sole conditions clearly appear to be inadequate to ensure safety during a flight neither to be up to the safety challenges.Flight safety at CNES/CSG(Centre National d’Etudes Spatiales/Centre Spatial Guyanais)is considered to be a full part job,to be performed separately from the launcher mission.Dedicated ground operators,namely safety officers,who are independent from launcher teams,are ultimately responsible for ensuring the safety.During the flight of a launcher,they are in charge of interrupting actively,making use of a flight termination telecommand from ground,the erroneous flight of a launcher before it endangers people or properties.Human factor is therefore of fundamental importance in flight safety at CNES/CSG.After a quick overview of CNES/CSG,this paper,based on the flight safety way of operation and on the safety officers recruitment,instruction,training and certification,aims at declining how the human factor is handled throughout all flight safety activities.