bluuebunny/crossref_metadata_2025 huggingface dataset:
To whom and how much? An assessment of philanthropic donation variety in relation to firm performance
Authors: Turner Kyle , Lee Joohun
Published: June 2024

Purpose

The purpose of this study is to test a model examining the effects of philanthropic portfolio diversity in relation to firm performance. In particular, the authors assess organizational philanthropy portfolios targeted at diverse issue categories while also examining these effects when the organization also partners with a diverse range of stakeholder groups.

Design/methodology/approach

The study leverages detailed company reports to collect, code and test a firm’s philanthropic behaviors based on focal issues such as community, education, environment and others. The authors also collect and analyze data on the range, type and quantity of stakeholders targeted by a firm’s philanthropic efforts. These philanthropic donations are then merged with financial data to examine the outcomes in a longitudinal analysis of over 2,000 firm-year observations.

Findings

The findings suggest that organizations that make focused and targeted philanthropic donations over a more generalist and broad approach realize higher performance. Furthermore, the authors find that variation across stakeholder donation amounts enhances firm performance by strategically identifying and targeting relevant stakeholder needs.

Originality/value

The present study expands on extant research to examine the performance implications associated with broad and general philanthropy versus targeted and narrow philanthropic efforts. Furthermore, the study provides support for a portfolio view of philanthropy to suggest organizations holistically assess, manage and leverage their efforts across issues and stakeholder groups. These findings provide additional insights into the complexities associated with corporate philanthropy portfolios while also discussing future research opportunities to enhance the outcomes associated with philanthropic activities.
Associations between enteral nutrition and outcomes in the SUP‐ICU trial: Results of exploratory post hoc analyses
Authors: Borthwick Mark , Granholm Anders , Marker Søren , Krag Mette , Lange Theis , Wise Matt P. , Bendel Stepani , Keus Frederik , Guttormsen Anne Berit , Schefold Joerg C. , Wetterslev Jørn , Perner Anders , Møller Morten Hylander
Published: June 2024

Background

Enteral nutrition may affect risks of gastrointestinal bleeding, pneumonia and mortality in critically ill patients and may also modify the effects of pharmacological stress ulcer prophylaxis. We undertook post hoc analyses of the stress ulcer prophylaxis in the intensive care unit trial to assess for any associations and interactions between enteral nutrition and pantoprazole.

Methods

Extended Cox models with time‐varying co‐variates and competing events were used to assess potential associations, adjusted for baseline severity of illness. Potential interactions between daily enteral nutrition and allocation to pantoprazole on outcomes were similarly assessed.

Results

Enteral nutrition was associated with lower risk of clinically important gastrointestinal bleeding (cause‐specific hazard ratio [HR]: 0.29, 95% confidence interval: [CI] 0.19–0.44, p < .001), higher risk of pneumonia (HR: 1.44, 95% CI: 1.14–1.82, p = .003), and lower risk of all‐cause mortality (HR: 0.22, 95% CI: 0.18–0.27, p < .001). Enteral nutrition with allocation to pantoprazole was associated with a lower risk of mortality (HR: 0.27, 95% CI: 0.21–0.35, p < .001), similar to enteral nutrition with allocation to placebo (HR: 0.17, 95% CI: 0.13–0.23, p < .001). Allocation to pantoprazole with no enteral nutrition had little effect on mortality (HR: 0.83, 95% CI: 0.63–1.09, p = .179), whilst allocation to pantoprazole and receipt of enteral nutrition was mostly compatible with increased all‐cause mortality (HR: 1.27, 95% CI: 0.99–1.64, p = .061). The test of interaction between enteral nutrition and pantoprazole treatment allocation for all‐cause mortality was statistically significant (p = .024).

Conclusions

Enteral nutrition was associated with an increased risk of pneumonia and a reduced risk of gastrointestinal bleeding. The interaction between pantoprazole and enteral nutrition suggesting an increased risk of mortality requires further study.
Prediction of corporate financial distress based on corporate social responsibility: New evidence from DANP, VWP and MEOWA weights methodologies
Authors: Li Hui , Sun Ting , Zhang Jinquan
Published: June 2024

This study investigates the determinants of financial distress from the corporate social responsibility (CSR) perspective and examines how poor CSR performance leads to financial distress in enterprises. Based on theoretical analysis, we select predictive indicators and construct an early warning indicator system for predicting financial distress from a CSR standpoint. Additionally, we develop a novel dynamic financial distress prediction (FDP) model using decision‐making trial and evaluation laboratory (DEMATEL)‐based analytic network process (DANP), variable weights with penalty (VWP), and maximal entropy ordered weighted average (MEOWA) weight methods to assess corporate financial status. Furthermore, to evaluate the accuracy of our model, we apply it to Chinese listed companies for empirical analysis using a sample of 1142 listed Chinese companies spanning 2011–2023. The results demonstrate that our developed FDP model exhibits higher predictive accuracy compared to previous models, suggesting that poor CSR practices can contribute to corporate financial distress while significantly enhancing FDP performance.
Histological tissue classification with a novel statistical filter‐based convolutional neural network
Authors: Ünlükal Nejat , Ülker Erkan , Solmaz Merve , Uyar Kübra , Taşdemir Şakir
Published: June 2024

Deep networks have been of considerable interest in literature and have enabled the solution of recent real‐world applications. Due to filters that offer feature extraction, Convolutional Neural Network (CNN) is recognized as an accurate, efficient and trustworthy deep learning technique for the solution of image‐based challenges. The high‐performing CNNs are computationally demanding even if they produce good results in a variety of applications. This is because a large number of parameters limit their ability to be reused on central processing units with low performance. To address these limitations, we suggest a novel statistical filter‐based CNN (HistStatCNN) for image classification. The convolution kernels of the designed CNN model were initialized by continuous statistical methods. The performance of the proposed filter initialization approach was evaluated on a novel histological dataset and various histopathological benchmark datasets. To prove the efficiency of statistical filters, three unique parameter sets and a mixed parameter set of statistical filters were applied to the designed CNN model for the classification task. According to the results, the accuracy of GoogleNet, ResNet18, ResNet50 and ResNet101 models were 85.56%, 85.24%, 83.59% and 83.79%, respectively. The accuracy was improved by 87.13% by HistStatCNN for the histological data classification task. Moreover, the performance of the proposed filter generation approach was proved by testing on various histopathological benchmark datasets, increasing average accuracy rates. Experimental results validate that the proposed statistical filters enhance the performance of the network with more simple CNN models.
Formula process and coloring mechanism of bluish‐white porcelains from the Lanxi kiln in Fujian, China
Authors: Wu Bo , Hu Baihui , Yang Zelin , Xu Hongxing , Chen Minxiao , Huang Yunying , Liang Kailai , Huang Hongxi , Xiong Huan
Published: June 2024

Bluish‐white porcelain was a prominent type of porcelain in ancient China, renowned for its distinctive artistic style and unique characteristics. The Lanxi kiln in Jianning County, Fujian Province, has unearthed a multitude of bluish‐white porcelain products from the Southern Song dynasty that exhibit vibrant glaze color and exceptional craftsmanship. The quality of these porcelains surpasses that of contemporaneous Jingdezhen and Baishe kiln products in Jiangxi Province, representing the pinnacle of bluish‐white porcelain excavated across various regions of China during the Southern Song dynasty. In this study, samples of bluish‐white porcelain from the Lanxi kiln and Baishe kiln, dating back to the Southern Song dynasty, were selected and analyzed via energy dispersive X‐ray fluorescence, ultraviolet–visible–near infrared (UV–Vis–NIR) spectrophotometer, metallographic microscopy, and scanning electron microscopy with EDS to investigate their glaze formula process and coloring mechanism. Moreover, these findings were subsequently compared with those of Jingdezhen bluish‐white porcelain from the same period. The results demonstrate that the raw materials of porcelain stones used in the glaze of the Lanxi and Jingdezhen kiln are similar in composition yet differ significantly from that employed in the Baishe kiln. Potassium feldspar was added to the glazes of the Baishe and Lanxi kiln, potentially existing exchanges of process of the two kilns due to their geographic proximity. The firing atmosphere of bluish‐white porcelain with different glaze colors in the same kiln exhibits significant variations. In particular, the lake blue sample undergoes firing under a strong reducing atmosphere, resulting in an excess content of Fe2+ in octahedral hexagon coordination within the glaze, thereby intensifying its blue hue. The colors of various glazes are determined by both chemical color and physical color. The former is a result of the absorption of Fe3+ in the ultraviolet region and the d‐d electron orbital transition of Fe2+ in the infrared region. However, the latter is not the scattering physical color but the diffuse reflection physical color produced by bubbles and anorthite crystallization layers.
The time scale of nomadic steelmaking from molten cast iron
Authors: Park Jang‐Sik
Published: June 2024

A structure consisting of roughly spherical particles of pearlite approximately 50 μm in diameter has repeatedly been observed in iron fragments excavated from across the Mongolian steppe. This structure illustrates a treatment where molten cast iron was subjected to an isothermal solidification reaction driven by the lowering of its carbon level through rapid decarburization. A simplified diffusion‐controlled model predicts that the reaction will be completed almost instantly once the cast iron reaches the fully molten state in an oxidizing environment. The technique apparently served as an effective process for small‐scale steelmaking, particularly in marginal steppe environments.
Impact of narcotics information management system on inappropriate benzodiazepine receptor agonist prescriptions: A quasi‐experimental analysis in South Korea
Authors: Son Hye Jin , Je Nam Kyung
Published: June 2024

Aims

The South Korean government implemented the narcotics information management system (NIMS) on 18 May 2018 to manage benzodiazepine receptor agonists (BzRAs) and narcotics effectively and establish a reporting mechanism for these drugs. This study assessed the effects of NIMS on inappropriate use of BzRAs.

Methods

Using national patient sample data from 2016 to 2020, we analysed adult outpatients who were prescribed oral BzRAs. We conducted a time series and segmented regression analysis using selected indicators to analyse the monthly variations related to the inappropriate use of these medications.

Results

The study revealed no significant changes in the indicators of inappropriate BzRA use following the NIMS implementation. Contrary to expectations, there was a significant increase in the proportion of patients exceeding defined daily dose (DDD) and in those receiving concurrent prescriptions of multiple BzRAs, following the implementation of NIMS. The immediate impact of the COVID‐19 pandemic was an increase in DDD exceedance; however, overall, this did not significantly affect BzRA use.

Conclusions

The introduction of NIMS did not significantly enhance the management of BzRA misuse. Additional measures, including continuous monitoring, system improvements and comprehensive education for prescribers and patients, are recommended to ensure the appropriate use of psychotropic medications.
Time‐varying brentuximab vedotin pharmacokinetics and weight‐based dosing in paediatric patients despite lower exposure in those aged 2 to <6 and 6–11 years
Authors: Zhang Daping , Zhang Zufei , Lee Anthony , Fenton Keenan , Jain Shweta , Garg Amit , Chia Yen Lin
Published: June 2024

Aims

We studied the pharmacokinetics and exposure–response relationships of the brentuximab vedotin (BV) antibody–drug conjugate (ADC) and unconjugated monomethyl auristatin E in haematologic malignancies.

Methods

This population pharmacokinetic analysis included data from five adult and three paediatric studies. Exposures in virtual adult and paediatric populations following BV 1.8 mg/kg (maximum 180 mg) intravenously every 3 weeks were simulated. Clinical endpoints included overall response rate, grade ≥2 peripheral neuropathy (PN) and grade ≥3 neutropenia.

Results

BV ADC exhibited linear pharmacokinetics, well‐described by a three‐compartment model, with body weight being the only significant covariate for exposure. Monomethyl auristatin E exhibited time‐varying formation rate. Simulated steady‐state BV ADC exposures in patients aged 12 to <18 years were similar to those of adult patients, but 23%–38% lower in patients aged 2 to <12 years. Despite lower exposure, clinical activity was observed with BV 1.8 mg/kg every 3 weeks in those aged 2 to <12 years (overall response rate: 2 to <12 years, 60%; 12 to <18 years, 43%). In adult, but not paediatric patients, increased BV ADC exposures were associated with grade ≥2 PN and grade ≥3 neutropenia occurrence.

Conclusions

BV pharmacokinetics in adult and paediatric patients were consistent. BV ADC exposures were lower in patients aged 2 to <12 years vs. ≥12 years, but no apparent clinically relevant differences in efficacy, grade ≥2 PN or grade ≥3 neutropenia were observed. These data support body weight‐based dosing of BV in patients irrespective of age; thus, dose adjustment in those 2 to <12 years does not appear warranted.
Settler colonialism and the administrative state: The transfer of the Government of the Northwest Territories to Yellowknife in 1967
Authors: Sabin Jerald
Published: June 2024

In September 1967, the federal government transferred the Government of the Northwest Territories from Ottawa to Yellowknife. While the transfer brought the machinery of government closer to the governed, it also established settler institutions in the homelands of Dene, Métis, and Inuit peoples. Using the tools of administrative history and settler colonial theory, this article reconstructs the transfer using newly released archival papers of NWT Commissioner Stuart Hodgson, who oversaw the transfer and the development of government in the NWT until 1979. It analyzes the role federal public servants played in facilitating settler colonial development in northwestern Canada and, in turn, how that development affected the structure and work of the federal public service in Ottawa. While the transfer entrenched Westminster parliamentary government in the NWT, it also served as a focal point for Indigenous resurgence and resistance that has remade contemporary governance in the territory.
Trends and hotspots of the neuroprotection of hypothermia treatment: A bibliometric and visualized analysis of research from 1992 to 2023
Authors: Zhang Yang , Jiang Miaowen , Baoying Song , Gao Yuan , Xu Yi , Qi Zhengfei , Wu Di , Li Ming , Ji Xunming
Published: June 2024

Aim

Recent studies have extensively investigated hypothermia as a therapeutic approach for mitigating neural damage. Despite this, bibliometric analyses specifically focusing on this area remain scarce. Consequently, this study aims to comprehensively outline the historical framework of research and to pinpoint future research directions and trends.

Methods

Articles spanning from 2003 to 2023, relevant to both “neuroprotection” and “hypothermia”, were sourced from the Web of Science Core Collection. The CiteSpace software facilitated a comprehensive evaluation and analysis of these publications. This analysis included examining the annual productivity, collaboration among nations, institutions, and authors, as well as the network of co‐cited references, authors and journals, and the co‐occurrence of keywords, and their respective clusters and trends, all of which were visualized.

Results

This study included 2103 articles on the neuroprotection effects of hypothermia, noting a consistent increase in publications since 1992. The United States, the University of California System, and Ji Xunming emerged as the most productive nation, institution, and author, respectively. Analysis of the top 10 co‐cited publications revealed that seven articles focused on the effects of hypothermia in infants with hypoxic–ischemic encephalopathy, while three studies addressed cardiac arrest. Shankaran S and the journal Stroke were the most frequently co‐cited author and journal, respectively. Keyword cluster analysis identified ischemic stroke as the primary focus of hypothermia therapy historically, with cardiac arrest and neonatal hypoxic–ischemic encephalopathy emerging as current research foci.

Conclusions

Recent studies on the neuroprotective effects of hypothermia in cardiac arrest and neonatal hypoxic–ischemic encephalopathy suggest that hypothermia may mitigate neural damage associated with these conditions. However, the application of hypothermia in the treatment of ischemic stroke remains confined to animal models and in vitro studies, with a notable absence of evidence from multicenter randomized controlled trials (RCTs). Further research is required to address this gap.
Evaluating museum exhibits: Quantifying visitor experience and museum impact with user experience methodologies
Authors: King Ellie , Smith M. Paul , Wilson Paul F. , Stott Janet F. , Williams Mark A.
Published: June 2024

Underpinned by the Model for Museum Exhibit User Experience (MEUX; King et al., Visitor Studies, 2023, 26, 59), this paper develops and presents an evaluation methodology for museum exhibits that utilizes existing methodologies from the user experience sector adapted for the museum and cultural heritage sectors. Two studies are presented: an in‐depth evaluation of the Meat the Future exhibition at Oxford University Museum of Natural History and then a comparative study between this exhibition and two other permanent exhibits at the museum. Quantitative and qualitative data provide a nuanced picture of each exhibit from the visitor perspective and showcase the benefits of the MEUX methods of evaluation. Results show how three different exhibits are constructed in different ways, providing different visitor experiences and outcomes. They are directly compared with identify statistical differences, but do not impose a judgment as to whether any exhibit is better than another. With detailed, nuanced and rigorous data capturing visitor experiences of engaging with exhibits, the MEUX evaluation methodology allows for more sophisticated, standardized and efficient evaluation practices within the sector, with results that directly support further development of exhibits and exhibitions.
The genetic determination of alternate stages in polyphenic insects
Authors: Erezyilmaz Deniz
Published: June 2024

Molt‐based transitions in form are a central feature of insect life that have enabled adaptation to diverse and changing environments. The endocrine regulation of these transitions is well established, but an understanding of their genetic regulation has only recently emerged from insect models. The pupal and adult stages of metamorphosing insects are determined by the stage specifying transcription factors broad‐complex (br) and Ecdysone inducible protein 93 (E93), respectively. A probable larval determinant, chronologically inappropriate metamorphosis (chinmo), has just recently been characterized. Expression of these three transcription factors in the metamorphosing insects is regulated by juvenile hormone with ecdysteroid hormones, and by mutual repression between the stage‐specific transcription factors. This review explores the hypothesis that variations in the onset, duration, and tissue‐specific expression of chinmo, br, and E93 underlie other polyphenisms that have arisen throughout insects, including the castes of social insects, aquatic stages of mayflies, and the neoteny of endoparasites. The mechanisms that constrain how chinmo, br, and E93 expression may vary will also constrain the ways that insect life history may evolve. I find that four types of expression changes are associated with novel insect forms: (1) heterochronic shift in the turnover of expression, (2) expansion or contraction of expression, (3) tissue‐specific expression, and (4) redeployment of stage‐specific expression. While there is more to be learned about chinmo, br, and E93 function in diverse insect taxa, the studies outlined here show that insect stages are modular units in developmental time and a substrate for evolutionary forces to act upon.
Integrated reporting quality and negative ESG media coverage: Empirical evidence from South Africa
Authors: Bellucci Marco , Crovini Chiara , Di Fabio Costanza , Simoni Lorenzo
Published: June 2024

This study draws upon media agenda‐setting theory to investigate the relationship between negative media coverage around environmental, social, and governance (ESG) issues and the quality of integrated reporting (IR). In particular, we examine the top 100 South African listed companies in the 2013–2018 timeframe for 317 firm‐year observations. Our results reveal that IR quality is positively related to negative ESG media coverage. Thus, a company exposed to more media pressure issues higher‐quality IR consistent with its need to face scrutiny and potential reputational damage and to restore or maintain its legitimacy. Results are robust to different measures of negative ESG media coverage, controlling for ESG disclosures, and are confirmed by analyses aimed at addressing endogeneity (instrumental variable approach, firm‐fixed effects, and matched samples). Subsample analyses show that financial sector reputational concerns do not impact our results. Additional tests show no long‐term effects of negative media coverage on IR quality and that sustainability embeddedness alleviates a company's response to negative ESG news in terms of enhanced reporting.
Status and influencing factors of frailty in hospitalized patients with chronic heart failure: A cross‐sectional study
Authors: Tang Miaoyan , Zhao Ruifang , Lv Qiaoxia
Published: June 2024

Objectives

To investigate the frailty status of inpatients with chronic heart failure (CHF) and analyse its influencing factors, so as to provide evidence for the early identification of high‐risk groups and frailty management.

Background

Early identification of frailty can guide the development and implementation of holistic and individualized treatment plans. However, at present, the frailty of patients with CHF has not attracted enough attention.

Design

A cross‐sectional study.

Methods

From June 2022 to June 2023, a convenience sample of 256 participants were recruited at a hospital in China. Multivariate logistic regression analysis was used to explore the influencing factors of frailty in patients with CHF, and an ROC curve was drawn to determine the cut‐off values for each influencing factor. STROBE checklist guides the reporting of the manuscript.

Results

A total of 270 questionnaires were sent out during the survey, and 256 valid questionnaires were ultimately recovered, resulting in an effective recovery rate of 94.8%. The incidence of frailty in hospitalized patients with CHF was 68.75%. Multivariable logistic regression analysis showed that age, self‐care ability, nutritional risk, Kinesiophobia and NT‐proBNP were risk factors for frailty, while albumin and LVEF were protective factors.

Conclusion

Multidimensional frailty was prevalent in hospitalized patients with CHF. Medical staff should take measures as early as possible from the aspects of exercise, nutrition, psychology and disease to delay the occurrence and development of frailty and reduce the occurrence of clinical adverse events caused by frailty.

Relevance to Clinical Practice

This study emphasizes the importance of the early identification of multidimensional frailty and measures can be taken to delay the occurrence and development of frailty through exercise, nutrition, psychology and disease treatment.

Patient or Public Contribution

Patients contributed through sharing their information required for the case report form and filling out questionnaires.
Effect of Face Mask on Lowering COVID‐19 Incidence in School Settings: A Systematic Review
Authors: Viera Luka
Published: June 2024

BACKGROUND

The emergence of COVID‐19 resulted in a substantial loss of education because of global school closures. Face masks are a potential measure to restrain the COVID‐19 spread; therefore, this paper evaluated the effectiveness of face masks in reducing COVID‐19 incidence in school settings.

METHODS

A systematic review was conducted by searching the literature in the Cochrane COVID‐19 Study Register and the World Health Organization COVID‐19 global literature. Data were summarized in tabular forms, and the findings were presented as narrative synthesis.

RESULTS

A total of 15,709 records were retrieved. The screening and selection led to the inclusion of 12 observational and 2 quasi‐experimental studies. Nine studies were conducted in different states, counties, or districts of the United States, and the remaining 5 were reported from Germany, Finland, Spain, and the United Kingdom. The results of 10 out of 14 studies favored mask use in reducing school COVID‐19 incidence. Three studies found no link between mask use and COVID‐19 incidences, whereas 1 quasi‐experimental study noted a higher COVID‐19 incidence with mask use in students aged 6‐11 years than no use of mask among preschool children aged 3‐5 years.

CONCLUSION

Mask mandates may lessen the incidence of respiratory infectious diseases in school settings during a pandemic; more well‐designed studies are warranted to clarify further the evidence regarding mask use in school settings.
Seed priming as a promising technique for sustainable restoration of dryland
Authors: Jarrar Heba , El‐Keblawy Ali , Albawab Mona , Ghenai Chaouki , Sheteiwy Mohamed
Published: June 2024

The success of plant growth and development in dryland restoration relies on seed germination, seedling development, and establishment. The lack of rainfall and extreme temperature variations in arid regions impede germination and seedling establishment, necessitating new approaches and techniques. The present review summarizes the vital role of seed priming techniques for the sustainable restoration of drylands through their effects on enhancing seed germination, seedling growth and development, plants' nutrient use efficiency, soil fertility, essential enzymes, microbial community, and stress adaptation ability, helping to alleviate the effects of abiotic stresses on plants. The importance of seed priming is discussed in both agricultural and ecological restoration contexts. Priming maximizes crop yields, reduces crop failure, and promotes eco‐friendly farming practices. In ecological restoration, seed priming enhances plant establishment and survival, contributing significantly to the restoration of native vegetation and wildlife habitats. The review categorizes seed priming techniques into six subcategories, highlighting their unique advantages for optimizing restoration efforts. The review highlights the underlying mechanisms of seed priming techniques to improve seed germination and plant development in dryland regions, particularly under salinity and drought constraints. While seed priming has proven effective, it also faces several limitations, such as cost, seed longevity, and environmental concerns. Investigating environmentally friendly priming methods and understanding the prolonged effects of priming on seed viability and the environment is crucial. Further research is needed to find cost‐effective, eco‐friendly seed priming methods, and to explore the genetic and molecular bases of stress tolerance in various plant species across diverse environments.
A computable general equilibrium model of the monetary policy implications for financial stability in South Africa
Authors: Beyers Conrad , Essel‐Mensah Kojo A. , Tsomocos Dimitrios P.
Published: June 2024

The South African Reserve Bank (SARB) uses interest rates to control inflation. The Computable General Equilibrium (CGE) model can contribute to inflation targeting objective and also determine the effects on banks and the economy. We improved the accuracy of the results from previous work on the banking sector CGE model by estimating the elasticities of the reduced form equations of the model instead of arbitrarily choosing them.

Our results conform with the established view that lower policy rates lead to an increase in inflation and a reduction in banks' profits. However, because of the adverse supply shocks arising from the effects of the COVID‐19 pandemic, the increase in the GDP is crowded out. The CGE model is a useful tool for the SARB for monetary policy implications on financial stability, informing and providing analysis on its repo rate decision, and determining the consequent effects on the economy.
Multidimensional Finite Element Models for Geometrically Nonlinear Dynamic Analyses of Rotating Blades
Authors: Azzara Rodolfo , Filippi Matteo , Carrera Erasmo
Published: June 2024

This study introduces multidimensional finite element models for conducting geometrically nonlinear analyses on rotating structures. The mathematical framework employed is based on the Carrera Unified Formulation, which provides a systematic approach for generating one-dimensional, two-dimensional, and three-dimensional finite element models with varying levels of accuracy. The multidimensional models developed using CUF consist of solid and beam elements. These models utilize a specialized 1D kinematic formulation that solely encompasses displacements as degrees of freedom. This formulation is achieved by combining Lagrange polynomials defined within sub-regions (or elements) bounded by an arbitrary number of points (or nodes). These characteristics align with conventional solid finite elements, facilitating a straightforward summation of inertial and elastic contributions at the shared interface nodes. The governing equations of the models incorporate the effects of rotation, including the Coriolis term and the spin softening matrix. The Green-Lagrange strain tensor’s linear and nonlinear terms are also considered in formulating the 3D and 1D finite elements. Numerical simulations have been conducted on various blade configurations. The obtained nonlinear solutions are compared with linearized ones and validated against results from existing literature.
OC-DICAM: One Class Defect Identification in Composite Aerostructure Material
Authors: Yunker Austin , Kettimuthu Rajkumar , Kral Zachary
Published: June 2024

One of the materials used in the design of aircraft structures is fiber-reinforced composites due to their good tensile strength and resistance to compression. During the manufacturing process, these structures are thoroughly inspected for flaws and defects to ensure structural integrity during commercial use. This non-destructive inspection (NDI) process can be done using ultrasonic testing (UT) due to its effectiveness at detecting flaws embedded within the material surface. Currently, the NDI process is done manually and can be a significant bottleneck in the manufacturing workflow. Artificial intelligence (AI) has shown success in numerous fields including computer vision, natural language processing, and recommendation systems. In this paper, we develop an AI-based assistance tool to drastically reduce inspection time. Typical AI workflows require large amounts of labelled data but defects rarely occur resulting in strong class imbalance. To overcome this, our method utilizes self-supervised learning (SSL) and only requires non-defect data during training. We verify our method using fuselage data generated in a production environment. We show that our method can effectively identify three common types of defects: delamination, foreign object debris (FOD), and porosity.
Rapid Numerical Assessment of Process-Induced Dimensional Changes and Residual Stresses in Large Aerospace Composite Parts
Authors: Zappino Enrico , Zobeiry Navid , Masia Rebecca , Petrolo Marco
Published: June 2024

Process-induced deformations (PIDs) are a major issue in fabricating composite aerostructures, hindering the assembly process. For example, geometrical mismatches between spars and wing skins can lead to considerable assembly delays during the assembly of a composite wing box. In these cases, shims with specific geometries, based on the mismatch of the original parts, are fabricated and used to meet the current tight tolerances in aerospace. Given such parts ‘complex and large geometry, process simulations to assess PIDs are often quite slow. This paper aims to evaluate the effect of geometry and design details on PIDs and residual stresses of composite spars efficiently and robustly. Typical cross-sectional geometries such as the Omega shape are considered. Furthermore, the impact of design details, including ply drop-off, on PIDs such as spring-in angles, warpage, and 3D stress distributions are evaluated along long spars.

The structural modeling is handled using 1D higher-order layer-wise theories based on the Carrera Unified Formulation (CUF) to speed up the process simulation of large parts. Such theories are necessary to detect relevant mechanical behaviors: transverse stretching, shear deformation, anisotropy, and layer-wise changes of the physical properties. On the other hand, using 1D theories significantly impacts the computational overhead as there are no aspect ratio constraints on the finite elements (FE), thus leading to much fewer degrees of freedom than 2D or 3D models. Although 1D, the model provides the complete 3D strain and stress fields as the primary unknowns — in this paper, pure displacements — are expanded using higher-order Lagrange polynomials to remove the typical assumptions of 1D modes, e.g., rigid cross-sections, null or constant shear distributions.

The evolution of material properties, such as the evolution of the degree of cure, viscoelastic moduli, and free strains, are characterized using established DSC and DMA tests. Accordingly, a cure-hardening instantaneously linear elastic (CHILE) constitutive model is adopted for numerical simulations. The results are verified through analytical formulations and published data in the literature. The proposed simulation approach allows for rapid evaluation of residual stresses and PIDs. Due to its numerical efficiency, the effect of various design parameters can be quickly evaluated. Therefore, this tool can explore the design space for large and complex composite parts and potentially develop mitigation strategies.
Determination of Cohesive Traction Separation Curve for Z-Pinned Interface Using Two Scale Homogenization
Authors: Davidson Paul
Published: June 2024

In this study a detailed numerical analysis is conducted to determine the traction-separation curve for z-pin under mode-I loading state. A single z-pin is modeled and studied with pre-stress and friction and cohesive interface modeled, to determine the traction-separation curves in mode-I. The results show that a traditional bi-linear or tri-linear traction separation curve is insufficient to capture the bending of z-pin and consequent frictional dissipation due to z-pin contact with the substrate. Based on this study, a new approach to parameterize traction-separation is proposed.
Electrical Characterization and Electromagnetic Interference Shielding Properties of Hybrid Buckypaper Reinforced Polymer Matrix Composites
Authors: Tripathi Kartik , Morales Madeline , Hamza Mohamed H. , Henry Todd C. , Hall Asha , Chattopadhyay Aditi
Published: June 2024

In recent years, there has been a growing interest in the utilization of carbon nanotubes (CNTs) to enhance electromagnetic interference (EMI) shielding capabilities within aerospace structures. Buckypaper (BP), which is an electrically conductive thin membrane made of highly cross-linked CNTs, provides an effective way to enhance the EMI shielding properties of carbon fiber reinforced polymer (CFRP) composites. However, limited work has been reported in predicting the frequency dependent electrical conductivity as well as EMI shielding effectiveness (SE) of hybrid BP/CFRP composites. In this paper, a novel quantum tunneling based equivalent circuit approach, in conjunction with Monte Carlo simulations, is employed to characterize the electrical properties of unidirectional CFRP plies. A frequency range of 1 GHz to 12 GHz corresponding to the L to X band frequency spectrum was considered for this study. It was observed that at 12 GHz the longitudinal conductivity decreases to ∼3,300 S/m from a DC conductivity level of 40,000 S/m, while the transverse conductivity concurrently rises from almost nil to ∼12.67 S/m. Subsequently, these results are integrated as effective lamina properties into Ansys High Frequency Structure Simulator (HFSS) to predict SE by simulating the transmission of electromagnetic waves across a semi-infinite shield representative volume element. The numerical simulations illustrate that the inclusion of BP leads to significant improvement in the SE. For an incident radiation at 12 GHz, the incorporation of a single BP interleaf enhances the SE of a [90,0] laminate by up to ∼64% while the incorporation of two BP interleaves in a [90,0,±45,0,90] balanced symmetric laminate enhances its SE by ∼20%. This enhancement can be attributed to the high conductivity of BP at high frequencies.
Analytical and Numerical Modeling of a Thermal Switch via Shape Changing Stimuli-Responsive Material
Authors: Owens Charles Abdol-Hamid , Farzinazar Shiva , Lee Jaeho
Published: June 2024

Here the authors present a thermal switch design composed of a stimuli-responsive material (SRM) component paired with a structured material (SM) component for thermal insulation applications. A numerical model is used to assess the performance of a point versus area contact switch design in a vacuum environment where the emissivity is set to ε ≥ 0.00, with a conduction-based analytical model developed to validate the numerical model for when ε = 0.00. A point contact switch is governed by contact at a singular point in the ON state to enhance thermal transport compared to the OFF state. Conversely, when an area contact switch is in the ON state, thermal transport occurs across a cross-sectional area rather than at a point. For the numerical solution of the temperature scalar field, a finite element method (FEM) approach discretizes the governing equations that are solved via the Newton-Raphson method. For the conduction-based analytical solution, a trigonometric approach based on the geometry of the design is used to find the geometrical factor and volume fraction, whose product with the material thermal conductivity produces the switching ratio. Numerical analysis reveals that increasing the contact area of the switching component results in a significant increase in the switching ratio, especially at the geometric limits of the design. When ε = 0, the switching ratio of the point contact is found to be approximately r = 1.54, while the area contact has a switching ratio up to r = 134.25 as the contact area increases to its largest value. The conduction-based analytical model produces a switching ratio that ranges from r = 1.12 to r = 102.61 as the contact area increases to its maximum value. For ε > 0, r increases with ε for s* ≤ 0.20, but r decreases with ε for s* ≥ 0.60, after undergoing an inflection for 0.20 < s* < 0.60. This inversion occurs due to the radiative thermal loss to the ambient environment. With a conduction-only model, the switching ratios of the analytical and numerical models are approximately identical and follow the same trend with increasing contact area. An extended numerical model investigates the thermal contact resistance and mechanical forces that may limit the efficiency of the switch design. This work provides a detailed quantitative analysis on how contact area strongly affects the performance of a thermal switch design that utilizes a stimuli-responsive material as the switching mechanism.
A Global-Local Modelling Approach for Wave Propagation, SHM and Damage Detection in Reinforced Panels Using Integrated Piezoelectric Sensors
Authors: Zappino Enrico , Najd Jamal , Carrera Erasmo , Harizi Walid , Aboura Zoheir
Published: June 2024

This paper presents forward a novel method for the damage detection in smart structures. The use of node-dependent kinematic models, based on the Carrera Unified Formulation, has led to an innovative global-local approach, with the ability to couple finite elements with different kinematics, and thus different levels of accuracy. With such approach it is possible to model a composite structure with embedded piezoelectric transducer, where the integrated patch or region is modelled using high-fidelity models, as the complex phenomena is expected to happen locally around that area. Thus, the use of layer-wise model is necessary on the level where higher accuracy is needed, as in the embedded area, whereas it remains possible to implement the cost efficient homogenized equivalent single layer models in other areas, reducing the computational cost. This approach has been used to study the lamb-wave propagation in reinforced composite panels, where a damage has been introduced. The detection of such damage through pitch and catch set-up has been studied. The reflected signal due to damage has also been investigated. The results show that this approach may provide accurate damage detection localization and accurate wave propagation despite the presence of localized models with sensors/ actuators.
Comparative study on variable axis lens systems based on tapered deflectors
Authors: Zhang Qingmao , Wang Qirui , Chen Delong , Liu Junbiao , Zhang Yanjun , Li Quantong , Liu Zhuming
Published: June 2024

A variable axis lens (VAL) concept has been demonstrated an effective method to reduce aberrations of electron beam machines and has been explored to several configurations. To implement the advantages of VAL fully, it is desirable to make the axial potential distribution of the objective lens match the deflection functions of deflectors well. To our knowledge, the electrostatic deflectors applied in electron-optical systems based on VAL concept are all constructed with a “cylindrical” shape. However, when a magnetic objective lens in the VAL configurations is constructed with different radii of upper and lower pole pieces, there is a mismatch between the asymmetric lens and cylindrical deflectors, which would lead to a significant increase in aberrations. With this in mind, we have developed tapered deflectors to address the foregoing problem. A comparative study on variable axis lens systems based on conventional cylindrical deflectors and the proposed tapered ones is undertaken. Simulation results demonstrate the validity and effectiveness of the proposed VALs to reduce aberrations and an electron beam landing angle.
Reactions From the Experts: Implications of Open-Source ActiGraph Counts for Analyzing Accelerometer Data
Authors: Montoye Alexander H.K. , LaMunion Samuel R. , Brønd Jan C. , Clevenger Kimberly A.
Published: June 2024

In 2022, it became possible to produce ActiGraph counts from raw accelerometer data without use of ActiLife software. This supports the availability and use of transparent, open-source methods for producing physical behavior outcomes from accelerometer data. However, questions remain regarding the implications of the availability of open-source ActiGraph counts. This Expert Question and Answer paper solicited and summarized feedback from several noted physical behavior measurement experts on five questions related to open-source counts. The experts agreed that open-source, transparent, and translatable methods help with harmonization of accelerometer methods. However, there were mixed views as to the importance of open-source counts and their place in the field moving forward. This Expert Question and Answer provides initial feedback, but more research both within this special issue and to be conducted moving forward will help to inform whether and how open-source counts will be accepted and adopted for use for device-based physical behavior assessments.
Biogenic-to-lithogenic handoff of particulate Zn affects the Zn cycle in the Southern Ocean
Authors: Duan J. , Cloete R. , Loock J. C. , Lanzirotti A. , Newville M. , Martínez-García A. , Sigman D. M. , Lam P. J. , Roychoudhury A. N. , Myneni S. C. B.
Published: June 2024

Zinc (Zn) is vital to marine organisms. Its active uptake by phytoplankton results in a substantial depletion of dissolved Zn, and Zn bound to particulate organic matter replenishes dissolved Zn in the ocean through remineralization. However, we found that particulate Zn changes from Zn bound to phosphoryls in cells to recalcitrant inorganic pools that include biogenic silica, clays, and iron, manganese, and aluminum oxides in the Southern Ocean water column. The abundances of inorganic pools increase with depth and are the only phases preserved in sediments. Changes in the particulate-Zn speciation influence Zn bioavailability and explain the decoupling of Zn and phosphorus and the correlation of Zn and silicon in the water column. These findings reveal a new dimension to the ocean Zn cycle, implicating an underappreciated role of inorganic Zn particles and their impact on biological productivity.
An in-depth exploration of the multifaceted roles of EVs in the context of pathogenic single-cell microorganisms
Authors: Feix Anna Sophia , Tabaie Emily Z. , Singh Aarshi N. , Wittenberg Nathan J. , Wilson Emma H. , Joachim Anja
Published: June 2024

Extracellular vesicles (EVs) have been recognized throughout scientific communities as potential vehicles of intercellular communication in both eukaryotes and prokaryotes, thereby influencing various physiological and pathological functions of both parent and recipient cells. This review provides an in-depth exploration of the multifaceted roles of EVs in the context of bacteria and protozoan parasite EVs, shedding light on their contributions to physiological processes and disease pathogenesis. These studies highlight EVs as a conserved mechanism of cellular communication, which may lead us to important breakthroughs in our understanding of infection, mechanisms of pathogenesis, and as indicators of disease. Furthermore, EVs are involved in host–microbe interactions, offering insights into the strategies employed by bacteria and protozoan parasites to modulate host responses, evade the immune system, and establish infections.