Risk Of Failure Research Articles

Probabilistic risk assessment of civil aircraft associated failures under condition-based maintenance

Maintenance can improve an aircraft system's reliability over a long operation period or when a component has failed. However, inappropriate maintenance inspection intervals will cause latent failures to be covered or undetected, leading to a large number of unplanned flight disruptions for airlines. In this paper, we present a two-stage framework to assess the associated failure risk of civil aircraft under condition-based maintenance. In the first stage of the framework, the probability of primary functional failure across the lifecycles of the monitored component is determined by analyzing whether the current inspection interval prevents the component from progressing from latent failure to functional failure. In the second stage of the framework, the associated failure probability between components and related systems is formulated by the adjacency matrix. The structure and performance of the proposed model were tested on a case study by run-to-failure data associated with aircraft engines from a large airline. Focusing on the scenario of turbine disk cracking leading to fragment penetration of the fuel tank and causing fire as the consequential fault impact path, the results show that the risk of aircraft fire caused by turbine disk fragments falls within an acceptable range, necessitating the completion of inspections and subsequent monitoring within the stipulated timeframe. The method can be used to readjust the inspection interval, optimize the operation plan, improve the on-time performance of flights, and reduce the risk of aviation accidents.

Temperature prediction of geothermal drilling considering the drilling fluid thermophysical parameters

An increasing number of geothermal wells are being drilled to meet the growing demand for geothermal energy. Given that the harsh environment of geothermal wells exposes drill-following tools to the risk of high-temperature failure, scholars have developed thermo-mathematical models to predict the temperature field distribution in wellbore. To the best of authors' knowledge, most models ignore the interaction between the fluid thermophysical parameters and its temperature. They also overlook the fact that the actual structure of the drilling column causes changes in the convective heat transfer coefficients between the fluid and the well wall, which subsequently affects heat transfer from the wellbore. In this study, we tested the changes of thermal property parameters of drilling fluid with density and temperature. Based on the actual drill string structure and considering the variation in thermophysical parameters during drilling fluids’ circulation, we innovatively established a transient heat transfer model for geothermal horizontal wells with heat–fluid–solid coupling. Subsequently, a drilled geothermal well was used to simulate the temperature during drilling. The effects of the drilling fluid system, density, and displacement, rotary speed, and WOB during drilling on the wellbore temperature distribution were analyzed. Furthermore, suggestions for the selection of drilling fluid and parameters during the drilling process were given. The results of this study can help accurately predict the wellbore temperature of geothermal wells and high-temperature wells, which provides guidance for the rational selection of drilling tools for drilling operations.

A comprehensive framework for estimating the remaining useful life of Li-ion batteries under limited data conditions with no temporal identifier

The escalating applications of Lithium-ion (Li-ion) batteries in renewable energy and electric vehicles underscore the need for enhanced prognostics and health management systems to reduce the risk of sudden failures. Remaining useful life (RUL) determination is one of the most critical tasks in the field of battery prognostics nowadays. Even though statistical and machine learning (ML) methods have proven effective in research setups, many challenges prevent applying these prediction methods to real-life scenarios. These challenges include (1) scarcity of run-to-failure datasets with similar experimental conditions, (2) low data granularity when presented in capacity vs. discharge cycle pairs, and (3) lack of “temporal identifiers” in real-life scenarios. A temporal identifier is any label that provides knowledge about the current degradation state of a working battery. The research question developed for this study was, ‘Can the remaining useful life of a Li-ion battery having limited data without a temporal identifier be predicted?’ The specific aims were to estimate the temporal identifier of limited data and to predict the remaining useful life (RUL). An innovative framework incorporating reliability analysis and deep learning addresses these specific aims. Experimental data is used to test the framework's capabilities, limiting the training dataset to only three batteries and the testing dataset to a small sample (< 10 data points) of another battery. This new approach enabled the RUL prediction to achieve errors as low as ∼5 cycles and root mean square error of 6.24 cycles, outperforming other benchmark studies on Li-ion battery RUL prediction that use more battery degradation data without temporal identifier.

8040 Precision-Engineered Activin and GDF Ligand Trap HS235: A Novel Lean Mass-Preserving Treatment for Obesity

Abstract Disclosure: G. Schang: Employee; Self; 35Pharma. M. De Molliens: Employee; Self; 35Pharma. E. Brule: Employee; Self; 35Pharma. C. Chauvet: Employee; Self; 35Pharma. J. Denis: Employee; Self; 35Pharma. A. Sours: Employee; Self; 35Pharma. V. Ganesh: Employee; Self; 35Pharma. G. Tremblay: Employee; Self; 35Pharma. J. Schoelermann: Employee; Self; 35Pharma. M. O'Connor: Employee; Self; 35Pharma. Introduction: Novel anti-obesity medications including incretin mimetics have revolutionized the pharmacotherapy of obesity and type 2 diabetes, leading to unprecedented weight loss and clinically meaningful improvement of glucose metabolism and cardiometabolic health. However, incretins reduce body mass in a non-selective manner; both fat mass and lean mass are lost with incretin treatment. In obese patients treated with incretins, undesirable loss of lean body mass (LBM) can account for up to 40% of overall weight loss. Loss of LBM negatively impacts resting metabolic rate, leading to a weight loss plateau and often unsustainable results. Furthermore, individuals with sarcopenia, characterized by low muscle mass and strength, are at greater risk for heart failure. The preservation, or even increase, of LBM is therefore a desirable treatment goal for obesity pharmacotherapy and overall cardiometabolic health. Activins and growth differentiation factors (GDFs), which are members of the TGF-beta superfamily, are validated targets controlling body composition and metabolism. Specifically, blockade of activins and GDFs has anabolic effects in metabolically active tissues such as skeletal muscle and brown adipose tissue, while reducing white adipose tissue mass. Therefore, specific and selective blockade of activins and GDFs represents a novel anti-obesity treatment strategy which can act orthogonally to current anti-obesity medications. HS235 is an activin receptor ectodomain-based (ActR) Fc-fusion protein that has been rationally designed to attain optimal inhibition of ligands controlling body composition in obesity. Methods: A structure-assisted rational molecular engineering approach coupled with cell-based potency screening was employed to design HS235. To validate the anti-obesogenic potential of HS235, diet-induced obese (DIO) mice were injected with HS235, an incretin mimetic, or a combination of both. Fat mass, LBM, muscle weights, and biomarker readouts were assessed at the end of study. Results: In cell-based assays, HS235 potently and selectively neutralized activins and GDFs implicated in body composition. This translated to complete in vivo target engagement and pharmacodynamic response. In a DIO mouse model, both HS235 and the incretin mimetic significantly improved metabolic parameters and decreased fat mass, but only HS235 increased LBM, while incretin-based treatment led to LBM loss. Importantly, the addition of HS235 to the incretin mimetic lead to a synergistic fat mass loss and prevented loss of LBM. Conclusion: Potent and selective inhibition of activins and GDFs by HS235 represents a novel LBM preserving weight loss strategy orthogonal to incretin mimetics. Collectively, these data support the development of HS235 as a novel anti-obesity agent to complement currently approved incretin-based medications to improve quality of weight loss. Presentation: 6/3/2024

7679 The Role of Thyrotoxicosis in Determining Clinical Outcomes for Hospitalized Patients with Dilated Cardiomyopathy: A Propensity Match National Cohort

Abstract Disclosure: R. Mukhtar: None. H. Younas: None. A. Taha: None. D. Virlan: None. A. Ceban: None. A. Racovita: None. J. Patel: None. Background: Thyrotoxicosis, a condition associated with high morbidity and mortality, has been notably linked to adverse clinical outcomes in patients with cardiovascular diseases. This study aims to comprehensively analyze the clinical impact of thyrotoxicosis on in-hospital outcomes in patients hospitalized with DCM. Methods: Based on 2020 National In-patient Sample Database, DCM patients were categorized into two groups depending on whether thyrotoxicosis was present or absent at the time of admission. To evaluate the impact of thyrotoxicosis on clinical outcomes, comparative analyses were conducted using propensity score matching and multivariable regression analysis. All statistical analyses were performed using STAT v 17. Results: Among 545,390 hospitalizations for DCM, 2,900 (0.5%) patients were presented with thyrotoxicosis. Propensity score matching revealed that DCM patients with thyrotoxicosis had higher heart failure rates (7.87% vs. 5.62%, aOR: 1.39, 95% CI: 1.04-1.86, p-value: 0.03). There was no statistically significant difference in in-patient mortality (2.60% vs. 3.65%, aOR: 0.81, 95% CI 0.58-1.13, p-value: 0.21), conduction disorders (3.26% vs. 2.70%, aOR: 1.38, 95% CI: 0.89-2.13, p-value: 0.15), acute coronary artery syndrome (0.62% vs. 0.86%, aOR: 0.94, 95% CI: 0.54-1.64, p-value: 0.82), acute kidney injury (18.57% vs. 18.59%, aOR 0.99, 95% CI: 0.77-1.17, p-value: 0.62), and acute stroke (0.29% vs. 0.30%, aOR: 0.60, 95% CI: 0.15-2.44, p-value: 0.48) between DCM patients with and without thyrotoxicosis. Thyrotoxicosis was associated with increased length of stay [5 days (IQR: 6) vs. 4 days (IQR: 7)] and total charge [$54,256 (IQR: 82,126) vs. $47,942 (IQR: 75,003)] in patients admitted with DCM. Conclusion: This research indicates that DCM patients co-presenting with thyrotoxicosis have an increased risk of heart failure and resource utilization during hospitalization. There were no significant effects observed in conduction disorders, in-patient mortality, acute coronary, kidney, or stroke outcomes among DCM patients hospitalized with or without thyrotoxicosis. Future prospective studies are warranted to enhance our understanding of clinical outcomes associated with thyrotoxicosis in patients hospitalized with DCM. Presentation: 6/3/2024

7306 Impact of Hypoglycemia in Heart Failure: National Inpatient Sample Analysis

Abstract Disclosure: B. Neupane: None. S. Karki: None. A. Bhandari: None. U. Farooq: None. K. Rajamani: None. Introduction:Hypoglycemia is one of the frequently encountered phenomena in hospitalized patients, mainly with diabetes mellitus; however, it is sometimes seen in patients without diabetes mellitus. Risk factors like advanced age, comorbid diseases, aggressive hyperglycemia therapy, etc., can play a role in the contribution of hypoglycemia. Heart failure is a significant healthcare burden in the United States; mortality due to heart failure has been increasing, and the lifetime risk of heart failure has risen to 24%. There are limited studies investigating how hypoglycemia affects outcomes in heart failure. Methods: We conducted a retrospective analysis using a national inpatient sample from 2017 to 2020. For diseases/comorbidities, International Classification of Disease (ICD-10) codes were used. Data analysis was done using STATA. Multivariate regression analysis was used to calculate the adjusted odds ratio. The primary outcomes of the study were mortality, and secondary outcomes were length of stay (LOS), total cost of hospitalization, septic shock, pulmonary edema, acute respiratory failure (ARF), mechanical ventilation, acute respiratory distress syndrome (ARDS), and acute kidney injury (AKI). Results: There was a total of 21,258,175 patients with a diagnosis of heart failure. There were 158,175 patients with a diagnosis of hypoglycemia. There were significant outcomes in patients with hypoglycemia on rates of mortality (adjusted mean difference=3.64, 14.55% vs. 4.91%, p&amp;lt;0.001), LOS (adjusted mean difference =2.03, 8.50% vs. 6.22%, p&amp;lt;0.001), the total cost of hospital stays (adjusted mean difference=$21530, $103,773 vs. $77057, p&amp;lt;0.001), septic shock( aOR=4.05, 14.22% vs. 3.84%, p&amp;lt;0.001), ARF(aOR =1.75, 24.71% vs. 15.88%, p&amp;lt;0.001), mechanical ventilation (aOR=2.84, 14.84% vs. 5.21%, p&amp;lt;0.001), ARDS( aOR=2.15, 0.57% vs. 0.24%,p&amp;lt;0.001), and AKI(aOR=1.65, 41.38% vs. 29.89%,p&amp;lt;0.001) compared to patients without hypoglycemia. There were no significant outcomes in the rate of pulmonary edema (aOR=1.09, 0.54% vs.0.46%, p=0.24). Conclusion: Hypoglycemia increases mortality, duration of hospital stays, health care cost, and health care burden. Hypoglycemia nevertheless results in worse hospital outcomes and higher expenses as compared to non-hypoglycemia due to higher mortality rates, LOS, cost, and hospital outcomes. Blood sugar levels should be monitored frequently to minimize hospitalization complications and improve outcomes. Presentation: 6/1/2024

8471 A Rare Case of Graves' Disease in a Three-Year-Old

Abstract Disclosure: A. Rajesh: None. A. Ravari: None. L.E. Kimball-Ravari: None. H. Roan: None. Graves’ Disease (GD) is an autoimmune disease that causes hyperfunctioning of the thyroid gland which may be triggered by environmental factors such as infection or stress. Though the leading cause of hyperthyroidism in both adult and pediatric populations is GD, it is extremely rare in children under the age of four years old. Some studies show the incidence to be 1 per 1,000,000 cases[1],2. Detecting GD in children early is very important as untreated GD poses a risk for failure to thrive. There have also been cases of young children suffering from psychomotor delays, craniosynostosis, and language delays because their suspected diagnosis of GD had not been detected for one to two years. In this article, we report the case of a previously healthy three-year-old Caucasian female who presented to the pediatric endocrinologist after collapsing from an episode of hypoglycemia; plasma glucose 47 mg/dL (71-180) . The patient was diagnosed with Graves’ Disease due to her significantly elevated free T3 and T4, decreased TSH, positive thyroid peroxidase (TPO) antibodies, and elevated TSIg. She was started on methimazole treatment; however, she did not respond after six months of ATD and underwent total thyroidectomy. Her hypoglycemia was attributed to abnormal proinsulin processing and glucose metabolism, which has been associated with hyperthyroidism; thyroid hormones can produce increased GLUT2 transporters3. This case report demonstrates the importance of recognizing the signs and symptoms of GD early, as well as discuss the importance of increasing the recognition of autoimmune diseases in the pediatric population.

Optimal Condition-Based Maintenance Policy Considering Nested Conditional Value-at-Risk and Operational Availability: A Case Study on Semiconductor Manufacturing Equipment

To address concerns regarding economic risks and reliability issues in existing maintenance practices, this study introduces a novel condition-based maintenance model that considers failure risks in terms of both cost and availability. Utilizing a Markov decision process, this model determines inspection intervals and maintenance policies aimed at minimizing the nested conditional Value-at-Risk of cumulative costs while satisfying operational availability constraints. By applying this model to the plasma etching process, we demonstrated its effectiveness compared to existing maintenance models. Additionally, we found that higher risk levels do not necessarily lead to stricter maintenance policies, whereas achieving better operational availability incurs additional costs. These findings highlight the importance of balancing cost and availability risks when determining an optimal maintenance policy.

Risk of Acute Complications with Rocuronium versus Cisatracurium in Patients with Chronic Kidney Disease: A Propensity-Matched Study.

Neuromuscular blocking agents (NMBAs) play an integral role in modern anesthesia by facilitating endotracheal tube placement, assisting with mechanical ventilation, and creating optimal surgical conditions. However, NMBAs can have deleterious side effects. The purpose of this study was to retrospectively analyze acute complications of 2 pharmacodynamically similar but pharmacokinetically different NMBAs and their respective reversal agents. The global research network database, TriNetX, was used to evaluate deidentified patient information from 63 health care organizations. Cohort A was defined as patients aged 18 to 80 years who had chronic kidney disease (CKD) and were administered rocuronium with sugammadex. Cohort B was defined as patients aged 18 to 80 years who had CKD and were administered cisatracurium with neostigmine. Cohorts were propensity matched for age at event, ethnicity, race, sex, and relevant confounding pathologies. All outcomes besides mortality were analyzed from the same day to 1 week after administration of the indexed drug. Mortality was analyzed from the same day to thirty days after administration of the indexed drug. A total of 95,740 patients with CKD-administered rocuronium with sugammadex were matched with 10,708 patients with CKD-administered cisatracurium with neostigmine. Patients administered rocuronium with sugammadex had a significantly higher associated risk of respiratory failure (risk ratios [RR], 1.98, confidence interval [CI], 1.71-2.29, P < .0001), acute respiratory distress (RR, 2.70, CI, 1.31-5.58, P = .0052), hypertensive crisis (RR, 1.85, CI, 1.37-2.49, P < .0001), heart failure (RR, 1.14, CI, 1.06-1.23, P = .0004), pleural effusion (RR, 1.30, CI, 1.14-1.49, P < .0001), and 30-day mortality (RR, 1.31, CI, 1.10-1.56, P = .0021). From 2003 to 2023, patients who were administered rocuronium plus sugammadex were at a significantly higher risk for acute cardiovascular and pulmonary complications when compared to patients who were administered cisatracurium plus neostigmine.

Design and Optimization of LPG Safety Cap using Finite Element Method

This paper presents a comprehensive study on the design and optimization of LPG safety caps, aimed at enhancing safety, reducing material consumption, and optimizing performance. The project employs SolidWorks simulation tools to conduct research and concept design phases. The primary objective is to ensure product safety while minimizing costs through Finite Element Analysis (FEA). The final product undergoes rigorous evaluation for performance and consumer safety. Three main goals guide this investigation: to scrutinize existing LPG safety cap designs, minimize material usage, and simulate the optimal design for enhanced safety. Analysis of the current design reveals vulnerabilities, including theft of LPG gas from sealed cylinders and escalating HDPE prices. Proposed designs simplify the current model and economize material consumption, successfully addressing the second objective. Through simulation, an optimal design (Design 8) emerges with superior characteristics compared to the existing model. Design 8 demonstrates a reduced total weight, higher safety factor, and lower maximum von Mises stress value. Notably, it exhibits enhanced safety and resilience, mitigating failure risks under stress conditions. The findings highlight the potential for creating stronger and safer designs while minimizing material requirements. In conclusion, Design 8 emerges as a superior alternative to the current design, boasting advantages in weight reduction, stress tolerance, safety factor, and optimization potential. This study underscores the significance of utilizing advanced computational methods to refine engineering designs for improved safety and efficiency in LPG safety caps.

A hybrid failure analysis model design for marine engineering systems: A case study on alternative propulsion system

Marine engineering systems have a fundamental role in ensuring the efficiency, safety, and sustainability of maritime transportation. The performance and reliability of these systems, particularly propulsion systems, are of paramount importance. This paper introduces a pioneering hybrid failure analysis model that integrate the Variable Weighted Synthesis Analytic Hierarchy Process (VWS-AHP) with the conventional Failure Mode and Effect Analysis (FMEA) methodology. The primary objective is to enhance the comprehension of failure modes within marine engineering systems, particularly focusing on alternative propulsion systems. While conventional FMEA is a widely employed methodology for analysis of failure modes, its capacity and effectiveness can be further augmented by integrating complementary techniques. The proposed hybrid model combines the robustness of FMEA in identifying failure modes with the VWS-AHP method’s ability to handle complex decision-making scenarios involving multiple criteria and varying levels of importance. This integration affords a comprehensive framework to assess failure risks, prioritize critical failure pathways, and evaluate the potential impacts of failures in marine engineering systems. To demonstrate the applicability of the proposed model, we conduct a case study on an alternative propulsion system. The outcomes of the case study showcase the efficacy of the hybrid model in enhancing FMEA.

Population-specific putative causal variants shape quantitative traits.

Human genetic variants are associated with many traits through largely unknown mechanisms. Here, combining approximately 260,000 Japanese study participants, a Japanese-specific genotype reference panel and statistical fine-mapping, we identified 4,423 significant loci across 63 quantitative traits, among which 601 were new, and 9,406 putatively causal variants. New associations included Japanese-specific coding, splicing and noncoding variants, exemplified by a damaging missense variant rs730881101 in TNNT2 associated with lower heart function and increased risk for heart failure (P = 1.4 × 10-15 and odds ratio = 4.5, 95% confidence interval = 3.1-6.5). Putative causal noncoding variants were supported by state-of-art in silico functional assays and had comparable effect sizes to coding variants. A plausible example of new mechanisms of causal variants is an enrichment of causal variants in 3' untranslated regions (UTRs), including the Japanese-specific rs13306436 in IL6 associated with pro-inflammatory traits and protection against tuberculosis. We experimentally showed that transcripts with rs13306436 are resistant to mRNA degradation by regnase-1, an RNA-binding protein. Our study provides a list of fine-mapped causal variants to be tested for functionality and underscores the importance of sequencing, genotyping and association efforts in diverse populations.

The effects of underlying inflammatory bowel disease on the outcomes of primary sclerosing cholangitis liver transplant recipients

IntroductionInflammatory bowel disease (IBD) influences primary sclerosing cholangitis (PSC) severity, however, the impact of IBD on PSC liver transplantation (LT) outcomes is poorly understood. We aimed to elucidate the impact of IBD in modulating PSC LT outcomes. MethodsUsing UNOS data from 2010 through 2021, we identified PSC LT candidates with and without (±) IBD. We used adjusted competing-risk regression analysis to evaluate waitlist outcomes, Kaplan-Meier analysis to assess graft survival, and Cox proportional hazards modeling to identify factors associated with graft survival. ResultsOut of 5,586 PSC candidates added to the waitlist, 3,652 patients had IBD. Older age (SHR 1.01; 95 %CI 1.01–1.02) and initial MELD/PELD (SHR 1.03; 95 %CI 1.02–1.04) were associated with increased risk of waitlist mortality, while private insurance (SHR 0.00; 95 %CI 0.00–0.01) with reduced risk. PSC-IBD LT recipients had increased prevalence of cholangiocarcinoma (4.8 % vs 3.4 %, p=0.005). Longer donor cold ischemia times (HR 1.06; 95 %CI 1.03–1.09), presence of recipient diabetes (HR 1.52; 95 %CI 1.13–2.05), and employment (HR 0.75, 95 %CI 0.60–0.94) had an increased risk of graft failure among PSC patients with IBD, not seen in those without IBD. ConclusionRegardless of IBD, LT for PSC results in excellent outcomes. Certain clinicodemographic factors impacted waitlist and recipient mortality highlighting potential targets to enhance outcomes.

Delayed graft function has comparable associations with early outcomes in primary and repeat transplant among deceased-donor kidney transplant recipients.

Delayed graft function (DGF) is a common complication and is associated with worse outcomes among kidney transplant recipients (KTRs). There are various risk factors for DGF including previous transplant. We hypothesized that DGF among KTRs undergoing repeat transplant has a greater impact on outcomes compared to primary KTRs. All deceased-donor KTRs between 01/2000 and 12/2020 at our center were included. Recipients were categorized as primary KTR or repeat KTR (any number of previous kidney transplants). Outcomes of interest included acute rejection, death-censored graft failure, and patient mortality within 12months post-transplant. A total of 3137 deceased-donor KTRs were included; 2498(80%) were primary KTRs and 639(20%) were repeat KTRs. The rates of DGF were similar between the groups at 29% and 28%, respectively. Compared to KTRs without DGF, DGF was associated with a greater incidence of death and graft failure in both primary and repeat transplants; however, the risk of rejection was not significantly higher in repeat KTRs (p = 0.72). Comparing primary and repeat KTRs, there were no significant differences in either acute rejection (p-interaction = 0.11), death-censored graft failure (p-interaction = 0.38), or death (p-interaction = 0.37). In subgroup analysis among repeat KTRs with DGF, a repeat transplant with no prior DGF was associated with increased risk for death-censored graft failure and death but not for acute rejection. DGF in the prior transplant was protective against death-censored graft failure (HR: 0.07, 95% CI 0.005-0.98, p = 0.05) (p-interaction = 0.04), but this was not significantly associated with acute rejection or death. DGF is associated with similar detrimental outcomes among primary and repeat KTRs.

Connected Food: First Steps for an Ambitious National Food Strategy

Background: The global food system faces growing pressure from population growth, climate change, wealth inequity, geo-political instability, and damage to the ecosystems on which our food supply depends. Fragmentation of the priorities and needs of food system stakeholders—citizens, food producers, food industries, governments—compounds the problem, with competing or misaligned interests increasing the risk of failure to adequately meet the needs of those that form, and are served, by the food system. Growing consensus on the need for transformative system level change to address the problems facing the food system is yet to be significantly reflected in strategic action. Methods: The national food strategy of the UK is offered as an exemplar to discuss the need to promote more coherent and ambitious visions of transformative change that acknowledge the complexity of the food system as a whole. We draw upon cross-sectoral experience to distil the needs, priorities, and key food system tensions that must be acknowledged to promote transformative systems change that equitably delivers healthy sustainable diets, contributes to a resilient global food system, and protects the environment. Results: Greater coherence, ambition, and consideration of the food system as a whole are needed if a UK national food strategy is to contribute to significant transformative change. Conclusions: To promote this, we advocate for (1) a food system digital twin to model and test potential food system interventions or legislation; (2) a citizens’ forum to inform and co-develop a cohesive national food strategy; and (3) increased cohesion and integration of food system governance within government to drive a coherent, ambitious national food strategy.

Experimental study of the performance of a water-to-water heat pump equipped with a liquid receiver with different charge levels

This paper presents an experimental investigation of the effects of a decreasing refrigerant charge on the performance and operating conditions of an R513A water-to-water heat pump equipped with a large liquid receiver, an electronic expansion valve, and a vapor accumulator at the compressor inlet. The mass of the refrigerant inside the machine is progressively extracted to simulate refrigerant leakages occurring during the normal operation or in case of failures. The results show that the subcooling is the parameter mostly affected by a refrigerant charge variation since it rapidly collapses to 0 K with the charge reduction. Furthermore, it is possible to identify three different zones in which almost all the properties analyzed (COP, heating capacity, operating pressures and expansion valve opening) exhibit peculiar trends with the charge decrease: subcooling sensitivity zone, constant parameters zone, and compressor failure risk zone. The extension of these zones is determined by the size of the liquid receiver which is installed in the system and, for the heat pump under consideration, is between 100% and 95% of the initial charge for the first zone, between 95% and 40% for the second zone, and below 40% for the third zone.

Towards a sustainable decision analysis approach for moisture-safe building envelope design

Energy-efficient building designs, notably through adding insulation, can reduce energy consumption and greenhouse gas emissions by over 40 %, but may also increase risk of condensation. Therefore, a comprehensive decision analysis approach is essential for selecting optimal building envelope assemblies while considering their hygrothermal, economic, and environmental implications. This study introduces a novel decision analysis method based on the inutility decision analysis (IDA) concept, in which the building envelope with the lowest inutility is considered the optimal choice. Initially, different building envelope assemblies were assessed through probabilistic hygrothermal analysis combined with a machine learning metamodel. Subsequently, the environmental and economic consequences associated with each assembly were quantified by integrating moisture-related damage into these assessments. Combining these outputs yielded inutility indices for the case studies, guiding the selection of the most optimal alternative. The results indicated that an external wall, with a minor risk of moisture-related failure, may outperform other alternatives when considering economic and environmental metrics. However, the final decision on the acceptability of such risk should rest with the customers or owners. Balancing the trade-off between performance longevity, cost, and occupants’ health is crucial.

Re-irradiation of anaplastic meningioma: higher dose and concomitant Bevacizumab may improve progression-free survival

IntroductionAnaplastic meningiomas, categorized as WHO grade 3 tumors, are rare and highly aggressive, accounting for 1-2% of all meningioma cases. Despite aggressive treatment, including surgery and Radiation, they exhibit a high recurrence rate and poor survival outcomes. The aggressive histopathological features emphasize the urgent need for effective management strategies.MethodsA retrospective multi-institutional analysis was conducted on patients with recurrent anaplastic meningioma who underwent re-irradiation between 2017 and 2023. Clinical, dosimetric, and outcome data were collected and analyzed, focusing on local control, progression free survival and treatment-related adverse events.ResultsThirty-four cases were analyzed, with a median follow-up 11 months after re-irradiation. Progression-free survival at 12 months was 61.9%, with higher doses correlating with better outcomes. Concomitant Bevacizumab improves progression-free survival and reduces the risk of radiation necrosis. CDKN2A homozygote deletion correlated with a higher risk of local failure. Symptomatic radiation necrosis occurred in 20.5% of cases, but its incidence was lower with concomitant Bevacizumab treatment.ConclusionRe-irradiation presents a viable option for recurrent anaplastic meningioma despite the associated risk of radiation necrosis. Higher doses with concomitant Bevacizumab improve clinical outcomes and reduce toxicity. Individualized treatment approaches are necessary, emphasizing the importance of further research to refine management strategies for this challenging disease.

Optimizing transplanting densities for lowland rice production under low-yielding environments in the Madagascar highlands

ContextRice yield is low at 2.1 t ha−1 in sub-Saharan Africa. Increased yield is a critical challenge to food security and environmental conservation in this region. However, smallholder farmers have limited access to irrigation, mineral fertilizers, and improved crop varieties. One approach that even resource-limited farmers can easily manipulate is to optimize planting densities. However, there is limited empirical evidence to provide technical recommendations under such low-yielding conditions. ObjectiveThis study aimed to identify the effect of dense transplanting on lowland rice yields under low-yielding conditions, with a target range below 5 t ha−1. MethodsMulti-field trials were implemented with transplanting densities of a regular rate at 25–26.7 hills m−2, a doubled rate at 50–53.3 hills m−2, and a tripled rate at 88.9 hills m−2 in the central highlands of Madagascar, where rice yields are limited by nutrient deficiency and low temperature. Canopy coverage and cumulative intercepted radiation (CIR) were monitored from transplantation to maturity using digital imagery analysis. Field observations (n=306) and four-year household surveys (n=356) were combined to calculate the costs and benefits of changing transplanting densities. ResultsDoubling densities from 25.0–26.7 hills m−2 to 50.0–53.3 hills m−2 had a consistent yield advantage by approximately 0.4 t ha−1 across a yield range of 1.8 t ha−1–4.4 t ha−1. The yield was further increased by tripling the transplanting densities to 88.9 hills m−2 when the yield range was 1.9–2.3 t ha−1. The yield advantage of higher transplanting densities was attributed to a greater CIR at the initial growth stages and a significantly greater panicle number. Household surveys and field observations indicated that the benefit of yield gain was more than three times greater than the additional cost of doubling the seed amounts. No significant yield differences were observed by changing the transplanting densities when the yield level was higher than 5 t ha−1 or lower than 1.3 t ha−1 where substantial reductions in grain fertility occurred owing to low-temperature stress. ConclusionsA relatively high transplanting density of 50–53.3 hills m−2 or even higher is recommended to ensure initial canopy development and panicle number in low-yielding conditions where individual plant growth is stagnant, except in fields with high risks of grain set failure. ImplicationsThis study provides an easy-to-use opportunity for smallholder farmers to increase their rice yield. Further studies are required to determine whether these findings apply to warmer climatic conditions.

Fatigue reliability analysis of bogie frames considering parameter uncertainty

With the increasing service life of bogie frames, the risk of fatigue failure becomes significant, making fatigue reliability analysis crucial for ensuring operational safety. However, accurately analyzing fatigue reliability presents a significant challenge with uncertain factors such as load fluctuations, unstable material shaping, and dimensional manufacturing deviations. To address this, this paper establishes a comprehensive active learning reliability framework based on surrogate models, enabling high-fidelity modeling and precise fatigue reliability analysis of welded frames under parameter uncertainty. The material utilization method was developed using APDL for secondary development to efficiently evaluate frame fatigue failure indicators. The effectiveness of this method was validated by combining the improved Goodman-Smith fatigue limit diagram and test bench fatigue tests, which helped identify the locations on the frame most prone to fatigue fractures. An Atom Search Optimization-BP Neural Network surrogate model was established with the objective of maximum material utilization, and the fatigue reliability of the bogie frame was obtained by combining the active learning function and the Monte Carlo method. The results show that the uncertainty design parameters greatly impact the fatigue reliability of critical welded structures. The proposed method improves the accuracy and efficiency of the fatigue reliability analysis of the bogie frame.