bluuebunny/crossref_metadata_2025 huggingface dataset:
Densification, deformation, and delamination during co‐sintering process of metal–ceramic laminates
Authors: Liu Chao , Deng Yuanbin , Gruner Daniel , Kaletsch Anke , Gestrich Tim , Broeckmann Christoph
Published: October 2024

Today, there is a high demand and increasing trend for multifunctional composite materials and components due to the combination of a wide range of favorable properties. However, undesired deformation leading to delamination, curvature, cracks, or even complete fracture frequently occurs during the co‐sintering process of metal–ceramic laminates (MCLs). To solve these issues, experimental work highly relies on the time‐consuming trial‐and‐error principle. This work aims to develop a thermo‐mechanical‐metallurgical model capable of predicting the densification, deformation, and delamination of MCLs during the co‐sintering process. It is found that the developed model successfully considers the inhomogeneous relative density distribution and phase transformation of the steel tape. In addition, a thin interlayer formed by a mixed slurry in the MCLs is modeled as cohesive elements to simulate the delamination process. The developed model is systematically validated by the experimental measurements and observations in terms of densification, deformation, and delamination during the co‐sintering process of the investigated laminate variants.
Innovative sample preparation using alcohol dehydration and high refractive index medium enables acquisition of two‐channel super‐resolution 3D STED image of an entire oocyte
Authors: Frolikova Michaela , Blazikova Michaela , Capek Martin , Chmelova Helena , Valecka Jan , Kolackova Veronika , Valaskova Eliska , Gregor Martin , Komrskova Katerina , Horvath Ondrej , Novotny Ivan
Published: October 2024

Super‐resolution (SR) microscopy is a cutting‐edge method that can provide detailed structural information with high resolution. However, the thickness of the specimen has been a major limitation for SR methods, and large biological structures have posed a challenge. To overcome this, the key step is to optimise sample preparation to ensure optical homogeneity and clarity, which can enhance the capabilities of SR methods for the acquisition of thicker structures.

Oocytes are the largest cells in the mammalian body and are crucial objects in reproductive biology. They are especially useful for studying membrane proteins. However, oocytes are extremely fragile and sensitive to mechanical manipulation and osmotic shocks, making sample preparation a critical and challenging step.

We present an innovative, simple and sensitive approach to oocyte sample preparation for 3D STED acquisition. This involves alcohol dehydration and mounting into a high refractive index medium. This extended preparation procedure allowed us to successfully obtain a unique two‐channel 3D STED SR image of an entire mouse oocyte. By optimising sample preparation, it is possible to overcome current limitations of SR methods and obtain high‐resolution images of large biological structures, such as oocytes, in order to study fundamental biological processes.

Lay Abstract: Super‐resolution (SR) microscopy is a cutting‐edge tool that allows scientists to view incredibly fine details in biological samples. However, it struggles with larger, thicker specimens, as they need to be optically clear and uniform for the best imaging results. In this study, we refined the sample preparation process to make it more suitable for SR microscopy. Our method includes carefully dehydrating biological samples with alcohol and then transferring them into a mounting medium that enhances optical clarity. This improved protocol enables high‐resolution imaging of thick biological structures, which was previously challenging. By optimizing this preparation method, we hope to expand the use of SR microscopy for studying large biological samples, helping scientists better understand complex biological structures.
Utility Tokens as a Commitment to Competition
Authors: GOLDSTEIN ITAY , GUPTA DEEKSHA , SVERCHKOV RUSLAN
Published: October 2024

We show that utility tokens can limit the rent‐seeking activities of two‐sided platforms with market power while preserving efficiency gains due to network effects. We model platforms where buyers and sellers can meet to exchange services. Tokens serve as the sole medium of exchange on a platform and can be traded in a secondary market. Tokenizing a platform commits a firm to give up monopolistic rents associated with the control of the platform, leading to long‐run competitive prices. We show how the threat of entrants can incentivize developers to tokenize and discuss cases where regulation is needed to enforce tokenization.
LncRNA LINC00261 associates with chemoresistance and clinical prognosis in patients with epithelial ovarian cancer
Authors: Tian Mei‐Ling , Li Bin , Li Yan , Fan Hong‐Wei , Du Nai‐Yi , Kang Shan
Published: October 2024

Objective

The purpose of this experiment is to explore the role of long intergenic noncoding RNA 261 (LINC00261) gene in the chemoresistance and clinical prognosis of epithelial ovarian cancer (EOC).

Methods

We used matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF) mass spectrometry to detect the methylation levels of the LINC00261 promoter region in EOC patient specimens. The expression levels of LINC00261, miR‐545‐3p, and MT1M in EOC patients were evaluated by quantitative real‐time reverse transcriptase PCR (RT‐qPCR). Spearman's correlation analysis was used for relevance analyses and clinical prognosis was counted by Kaplan–Meier analysis. Stable overexpressed LINC00261 SKOV3 cells were established to test the influence of LINC00261 on proliferation, platinum sensitivity, migration, and invasion.

Results

The promoter region methylation level of the LINC00261 was hypermethylated and LINC00261 was significantly downregulated in platinum‐resistant EOC tissues. The methylation level of LINC00261was significantly negative correlated with its RNA expression in EOC. Moreover, hypermethylation and lower expression of LINC00261 in EOC patients were related to shorter progression‐free survival (PFS) and overall survival (OS). Furthermore, Spearman's correlation analysis showed that the expression of miR‐545‐3p had a negative relevance with LINC00261. According to the website prediction, MT1M might be the downstream target gene of LINC00261. Expression of MT1M was negatively correlated with miR‐545‐3p and positively with LINC00261 in EOC tissues. And lower MT1M mRNA expression was correlated with chemotherapy resistance and worse prognosis. In vitro, overexpression of LINC00261 could inhibit cisplatin resistance, proliferation, and suppression of migration and invasion in SKOV3 cells.

Conclusions

This research indicates that the aberrant hypermethylation and low expression of LINC00261 were associated with platinum resistance and adverse outcomes in EOC patients.
Is early pregnancy hemoglobin A1c useful to predict gestational diabetes mellitus diagnosed during mid pregnancy?
Authors: Nakanishi Sayuri , Aoki Shigeru , Iwama Noriyuki , Yasuhi Ichiro , Sugiyama Takashi , Miyakoshi Kei
Published: October 2024

Aims

To verify whether hemoglobin A1c (HbA1c) levels in early pregnancy can predict the diagnosis of gestational diabetes mellitus (GDM) in mid‐pregnancy.

Materials and Methods

This was a retrospective cohort study of 2008 pregnant women who delivered singletons at the Yokohama City university Medical Center. Concomitant or history of diabetes mellitus and overt diabetes in pregnancy were excluded. Pregnant women at high risk for GDM underwent a one‐step 75‐g oral glucose tolerance test (OGTT) during mid‐pregnancy. For other pregnant women, GDM was diagnosed by a two‐step 75‐g oral glucose tolerance test (OGTT) when the 50‐g glucose challenge test result in mid‐pregnancy was ≥140 mg/dL. The thresholds for 75‐g OGTT followed those of the International Association of Diabetes and Pregnancy Study Group (IADPSG) criteria (92‐180‐153 mg/dL). The relationship between HbA1c level measured at <20 weeks of gestation and GDM diagnosis at mid pregnancy was assessed using a receiver operating characteristic curve (ROC); area under the curve (AUC) and optimal cutoff value of HbA1c, predictive of GDM were calculated.

Results

The median HbA1c level at <20 weeks of gestation was 5.3%, and 8.5% of women were diagnosed with GDM. In the ROC curve of the GDM diagnosis rate by HbA1c level, AUC was 0.706, and the optimal cutoff value was 5.4%, with a sensitivity of 0.6176, specificity of 0.6834, positive predictive value of 15.4%, and negative predictive value of 95.1%.

Conclusions

Although HbA1c at less than 20 weeks of gestation is acceptable discrimination as a diagnostic tool of GDM in mid‐pregnancy, it is not clinically useful to predict GDM in mid‐pregnancy.
Regulating for trustworthy autonomous systems: exploring stakeholder perspectives on answerability
Authors: HATHERALL LOUISE , SETHI NAYHA
Published: October 2024

The proliferation of autonomous and semi‐autonomous systems (AS) poses important and pressing regulatory challenges. Underpinning these is the recognition that many different stakeholders will need to trust systems to ensure their effective adoption and implementation. However, research on stakeholder perspectives is lacking, and assessing trustworthiness is difficult due to ‘responsibility gaps’ where it is unclear where responsibility for harms arising from AS ought to lie. Bridging these gaps is important because holding one another responsible is how social trust is maintained, and trust is vital to unlocking the promise that AS hold. This article considers how the concept of answerability could provide a useful framework for boosting the trustworthiness of AS. We present findings from a series of stakeholder interviews identifying what answers different stakeholders need to trust AS in health, finance, and government applications, and consider the implications of our research for current proposals for regulating AS in the United Kingdom and the European Union.
Evaluation of paediatric herpes zoster cases: Comparison of herpes zoster attacks in children with and without underlying conditions
Authors: Gadimova Aysel , Arga Gül , Taşkın Esra Çakmak , Konca Hatice Kübra , Özdemir Halil , Çakmaklı Hasan Fatih , İnce Elif , İleri Talia , Dinçaslan Handan , Taçyıldız Nurdan , Ünal Emel , Ertem Mehmet , İnce Erdal , Çiftçi Ergin
Published: October 2024

Aim

Herpes zoster is rarely seen in children, but is more common and more severe in those with underlying medical conditions. The purpose of this study was to comprehensively evaluate cases of herpes zoster in all paediatric patients and to detail the clinical course and complications of this disease in children with and without underlying health problems in terms of similarities and differences.

Methods

The course of paediatric patients diagnosed with herpes zoster in a tertiary university hospital over a 19‐year period was evaluated from the time of diagnosis, divided into groups with and without underlying disease.

Results

In our study, where we evaluated 150 herpes zoster attacks in 143 children, 79.3% of the patients (n = 119) had underlying diseases, while 20.7% (n = 31) were healthy children. The age at the time of primary varicella‐zoster virus and herpes zoster was significantly younger in the group without an underlying disease compared to the group with an underlying disease. Pain was reported more in the healthy group, and the duration of symptoms was longer. Ophthalmic nerve involvement was significantly higher in the group without a known disease. Treatment was administered in 90% of all attacks. In the group with underlying diseases, the duration of intravenous treatment and hospital stay were significantly higher as expected.

Conclusions

This study shows that herpes zoster attacks in healthy children can also progress with severe symptoms and complications. Approaches to reduce the burden of herpes zoster should be adopted and developed for all paediatric patients.
Effects of Chitosan‐Based Additive on Rumen Fermentation and Microbial Community, Nutrients Digestibility and Lactation Performance in Goats
Authors: El‐Zaiat Hani M. , Al‐Marzooqi Waleed , Al‐Kharousi Kaadhia
Published: October 2024

Recently, the potential of using chitosan (CHI) as a feed additive to enhance ruminal fermentation and improve animal performance has gained increasing attention in ruminant nutrition. This study was undertaken to investigate the effect of dietary supplementation with increasing doses of CHI on rumen fermentation attributes and microbial composition, digestibility and milk performance in Dhofari goats. Twenty‐four lactating goats (27 ± 1.8 kg of initial live body weight) were fed a control diet comprising of Rhodes grass hay plus a concentrate feed mixture. Goats were assigned to one of three experimental treatments (n = 8 per treatment) as: (1) control diet with no supplement (CTRL), (2) control diet with 0.300 g/day CHI (CHI0.3) and (3) control diet supplemented with 0.600 g/day CHI (CHI0.6) for a 45‐day experimental period. Dietary supplementation with increasing doses of CHI decreased (p < 0.05) linearly ruminal pH (p = 0.023), total short chain fatty acids concentrations (p = 0.011), acetate (p = 0.013) and butyrate (p = 0.042) proportions, acetate to propionate ratio (p < 0.001), estimated methane (CH4) production (p < 0.001), ammonia nitrogen concentrations (p = 0.003) and protozoa abundance (p = 0.003). However, the ruminal propionate proportion augmented (p = 0.002) linearly with increasing doses of CHI in the diet. Increasing doses of CHI linearly increased the abundance of the ruminal propionate‐producing bacteria, while diminished acetate and CH4‐producing bacteria (p < 0.05). Serum total protein (p = 0.037) and glucose (p = 0.042) levels linearly increased as CHI doses increased in the diet. However, serum UREA levels decreased linearly (p = 0.002) by 21% with increasing CHI amounts in the diet. The digestibility of organic matter, crude protein and neutral detergent fibre increased linearly with the increasing CHI doses (p < 0.05). Neither linear nor quadratic responses (p > 0.05) were observed in daily milk yield and feed efficiency by supplementing the diet with CHI. In conclusion, supplementing the diet with CHI at a dose of 0.600 g/day as a feed additive for dairy goats reduced estimated CH4 generation and improved fibre and protein digestion, with no influence on feed intake, milk yield or composition.
Barriers and facilitators to healthy eating during post‐partum among non‐Hispanic Black mothers
Authors: Kay Melissa C. , Bentley Margaret , Wasser Heather
Published: October 2024

Maternal diet is a key predictor of child diet, yet an in‐depth inquiry into the barriers and facilitators for the adoption of healthy eating behaviours during the post‐partum period is lacking, specifically for non‐Hispanic Black mothers. This study used qualitative research methods to investigate healthy eating practices among a sample of non‐Hispanic Black mothers participating in a family‐based obesity prevention intervention. In‐depth interviews were conducted with 22 mothers who participated in the Mothers and Others: Family‐based Obesity Prevention for Infants and Toddlers intervention trial. Interviews were audio‐recorded and transcribed verbatim. A deductive and inductive process was used to develop a consensus codebook; once the data were coded, matrices were developed to explore the data and identify similarities and differences between respondents. Relevant themes were identified, and salient quotes were used to illustrate each theme. Mothers believed that time and taste were significant barriers to eating healthy. Social influence and social support had both positive and negative influences on mothers' ability to adopt healthy eating behaviours. Despite their children often being a facilitator to healthy eating, many mothers struggled with finding the time, energy and desire to focus on themselves when it came to healthy eating. Many mothers were intent on preparing healthy meals and snacks for their children but did not prepare them for themselves. Future interventions should focus on the importance of role‐modelling healthy eating behaviours for their children and include behaviour change strategies that incorporate skill‐building activities emphasizing time‐saving methods for planning and preparing healthy meals and snacks for the whole family to eat.
Darwin and the question of agency in nature and science
Authors: Riskin Jessica
Published: October 2024

Like the Romantics, Charles Darwin was deeply though fruitfully torn between the mechanist dictate to banish agency from nature and the organicist impulse to naturalize agency, to make agency synonymous with life. His conflicting intellectual inheritances and allegiances put him in a state of profound and extraordinarily productive ambivalence.
Enter the matrix: Examining the psychosocial determinants of support for a technocracy of artificial intelligence
Authors: Dono Marcos , Moreno Bella Eva
Published: October 2024

Artificial Intelligence (AI) stands as the most transformative technology since the Industrial Revolution. As AI is integrated into different domains of life, it is likely to also permeate politics. In fact, some voices already advocate for AI to make political decisions. This paper emphasizes the necessity to delve into the psychosocial determinants shaping support for supporting a technocracy of AI (TecAI). The research aims to ascertain whether anomie, moderated by NCC and SDO, predicts support for TecAI across three studies involving Spanish participants (Ntotal = 754). The findings confirm anomie's predictive power on support of TecAI, albeit without establishing causality consistently, as anomie's condition failed to alter support for TecAI in experiments 2 and 3. However, an exploratory analysis showed a small effect of the subdimension of “breakdown of leadership” on support for TecAI in a directional test, informing future research. Moreover, NCC and SDO did not significantly moderate the anomie‐support‐for‐TecAI link. Ideology also emerged as a consistent predictor, with conservatives consistently showing more support, a finding that ought to be re‐examined and clarified. This study marks an initial empirical exploration into AI's political perceptions, hinting at the need for further investigation into this critical domain.
Repeat Breeder Syndrome Therapies in Dairy Cows: A Review
Authors: Carbonari Alice , Burgio Matteo , Frattina Lorenza , Cicirelli Vincenzo , Rizzo Annalisa
Published: October 2024

Repeat breeder (RB) cows are clinically healthy animals with regular oestrous cycles that do not become pregnant after three or more services. This syndrome has an incidence ranging between 10.1% and 24%. Repeat breeder syndrome (RBS) in dairy cows leads to economic losses to dairy farmers by increasing the calving interval and consequently reducing milk and calf production. RBS has a complex oetiopathogenesis as many factors are involved in its onset. The causes can be grouped into two categories: causes leading to fertilisation failure and factors leading to early embryonic death. Accurate identification of the cause and early diagnosis of RBS is essential to minimise the problems that this issue brings to the farm, but is not always possible. Hypothesising the underlying aetiology of the syndrome is also crucial for targeted therapy, whether pharmacological or managerial. The aim of this review is to report the different therapies, proposed in the literature, for the treatment of RBS in cattle, based on the knowledge of possible aetiological causes.
A decision analysis of cancer patients and the consumption of ready‐to‐eat salad
Authors: Gomez Carly B. , Mitchell Jade , Marks Bradley P.
Published: October 2024

Listeria monocytogenes is a foodborne pathogen of concern for cancer patients, who face higher morbidity and mortality rates than the general population. The neutropenic diet (ND), which excludes fresh produce, is often utilized to mitigate this risk; however, an analysis weighing the theoretical listeriosis risk reduction of produce exclusion aspects of the ND and possible negative tradeoffs has never been conducted. Consequently, this work constructed decision analytic models using disability‐adjusted life years (DALYs) to compare the impacts of the ND, such as increased neutropenic enterocolitis (NEC) likelihood, with three alternative dietary practices (safe food handling [SFH], surface blanching, and refrigeration only) across five age groups, for cancer patients who consume ready‐to‐eat salad. Less disruptive diets had fewer negative health impacts in all scenarios, with median alternative diet DALYs per person per chemotherapy cycle having lower values in terms of negative health outcomes (0.088–0.443) than the ND (0.619–3.102). DALYs were dominated by outcomes associated with NEC, which is more common in patients following the ND than in other diets. Switchover point analysis confirmed that, because of this discrepancy, there were no feasible values of other parameters that could justify the ND. Correspondingly, the sensitivity analysis indicated that NEC mortality rate and remaining life expectancy strongly affected DALYs, further illustrating the model's strong dependence on NEC outcomes. Given these findings, and the SFH's ease of implementation and high compliance rates, the SFH diet is recommended in place of the ND.
The Case of the DOXA Four: A Year in the School of Political Prisoners
Authors: Osipova Anastasiya
Published: October 2024

This paper explores media strategies used by the four former editors of the Russian independent student‐run journal DOXA during their year of pre‐trial domestic confinement between April 2021 and April 2022. This high‐profile case ended only two months after the beginning of Russia’s full‐scale war in Ukraine and the intensification of repressions against the internal political opposition. It also concludes a decade‐long phase in the conflict between the Russian state and its increasingly politicized youth. By maintaining a public presence during their house arrest despite the official prohibition, the DOXA Four entered into a media competition with police: Both groups were trying to reach an audience of Russian youth and shape the public image of oppositional students. While the state strove to intimidate, infantilize, and isolate the young people, the DOXA editors promoted collectivist forms of feeling and imagination to encourage political mobilization. In doing so, they aimed to break with the prevailing culture of ironic aestheticization of state violence and to re‐articulate political aesthetics for its generation.
Physiological influences on neurovascular coupling: A systematic review of multimodal imaging approaches and recommendations for future study designs
Authors: Burma Joel S. , Bailey Damian M. , Johnson Nathan E. , Griffiths James K. , Burkart Josh J. , Soligon Clara A. , Fletcher Elizabeth K. S. , Javra Raelyn M. , Debert Chantel T. , Schneider Kathryn J. , Dunn Jeff F. , Smirl Jonathan D.
Published: October 2024

In this review, we have amalgamated the literature, taking a multimodal neuroimaging approach to quantify the relationship between neuronal firing and haemodynamics during a task paradigm (i.e., neurovascular coupling response), while considering confounding physiological influences. Original research articles that used concurrent neuronal and haemodynamic quantification in humans (n ≥ 10) during a task paradigm were included from PubMed, Scopus, Web of Science, EMBASE and PsychINFO. Articles published before 31 July 2023 were considered for eligibility. Rapid screening was completed by the first author. Two authors completed the title/abstract and full‐text screening. Article quality was assessed using a modified version of the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross‐Sectional Studies. A total of 364 articles were included following title/abstract and full‐text screening. The most common combination was EEG/functional MRI (68.7%), with cognitive (48.1%) and visual (27.5%) tasks being the most common. The majority of studies displayed an absence/minimal control of blood pressure, arterial gas concentrations and/or heart rate (92.9%), and only 1.3% monitored these factors. A minority of studies restricted or collected data pertaining to caffeine (7.4%), exercise (0.8%), food (0.5%), nicotine (2.7%), the menstrual cycle (0.3%) or cardiorespiratory fitness levels (0.5%). The cerebrovasculature is sensitive to numerous factors; thus, to understand the neurovascular coupling response fully, better control for confounding physiological influences of blood pressure and respiratory metrics is imperative during study‐design formulation. Moreover, further work should continue to examine sex‐based differences, the influence of sex steroid hormone concentrations and cardiorespiratory fitness.
Optimizing Supercritical Carbon Dioxide Cycles Performance With Respect to Split Ratio and Intermediate Pressure
Authors: Tatli Akif Eren , You Dongchuan , Metghalchi Hameed
Published: October 2024

Supercritical carbon dioxide power cycles are getting more attention every day due to their high efficiencies. This study has examined determination of split ratio and intermediate pressure for maximum efficiency in various supercritical carbon dioxide recompression cycle configurations. Five cycle variants have been analyzed: reheating, partial cooling, partial cooling with reheating, intercooling, and intercooling with reheating. Partial derivatives of efficiency with respect to split ratio and intermediate pressure have been determined and set equal to zero to find optimum split ratio and intermediate pressure. This process has isolated the system's response to these two key parameters while keeping other cycle variables constant. Across all configurations, following parameters have been fixed: inlet temperatures of 550 °C and 32 °C for turbine and compressor components, an energy source temperature of 600 °C, an ambient temperature of 27 °C, and pressure limits of 75 bar and 200 bar. Optimization results show that recompression–reheating cycle achieves the highest efficiency of 39.62% at an optimum intermediate pressure of 139.43 bar and a split ratio of 71.1%. Recompression–partial cooling cycle exhibits the lowest maximum efficiency at 37.35%, with an optimum intermediate pressure of 85.87 bar and a split ratio of 62.6%. Recompression–partial cooling with reheating cycle reaches a maximum efficiency of 37.98% at an optimum intermediate pressure of 123.94 bar and a split ratio of 67.2%, while the intercooling cycle and intercooling with reheating cycle attain 39.57% at an optimum intermediate pressure of 80.03 bar and a split ratio of 66.4% and 39.59% at an optimum intermediate pressure of 116.1 bar and a split ratio of 69.2%, respectively. Additionally, exergy destruction has been calculated for all components of the system and it is related to thermal efficiency of the cycle.
Predicting the Effects of Cryogenic Treatment and Impact-Oscillatory Loading on Changes in the Strength Properties of Stainless Steels
Authors: Chausov Mykola , Maruschak Pavlo , Pylypenko Andrii , Shmanenko Vladyslav
Published: October 2024

New experimental results concerning the strength properties of stainless steels are analyzed. In particular, the strength properties of steels were improved at room temperature using the preliminary impact-oscillatory loading (IOL) in liquid nitrogen. Mechanical tests performed on stainless steel 12Kh18N10T have found the IOL conditions (deformation of the material during pulse loading—εimp = 9.69%), under which the ultimate strength of steel increases by 32.2% compared to the initial state under subsequent static tensioning. Metallographic analysis of the deformed steel revealed twinning in the microstructure. This accounts for a significant increase in ultimate strength under subsequent static tensioning. A method for estimating the ultimate strength of stainless steels of different chemical compositions by changing the percentage of the main chemical elements is proposed. To test this technique, stainless steel 12Kh18N9 was chosen. Similar studies using this steel at εimp = 9.5% in liquid nitrogen followed by static tensioning at room temperature have confirmed the effectiveness of the proposed approach.
Design and Simulation of eVTOL Aircraft Thermal Management System
Authors: Kang Sangkeun , Saias Chana Anna , Roumeliotis Ioannis , Broca Olivier
Published: October 2024

This paper focused on designing a thermal management system (TMS) for a parallel hybrid electric (PHE) XV-15 tiltrotor aircraft used in urban air mobility (UAM) applications. The TMS is integrated into the aircraft system to assess its impact at aircraft and mission levels. Both liquid cooling and air-cooling TMS, along with using phase change materials (PCMs) for heat storage, were designed and assessed. Two liquid-cooling configurations, series and parallel, were evaluated, with the series configuration proving more effective in the considered test cases. The study compared hover and cruise conditions to determine optimal design point for the liquid-cooling TMS. Designing for hover resulted in about fourfold increase in the TMS penalty in fuel burn during cruise. Designing for cruise, on the other hand, proved infeasible to comply with the thermal management requirements during hover. Two approaches were explored to address this: Approach A involves adding PCMs as a heat storage system and approach B entailed redesigning the TMS with the heat load at off-design conditions for the inverter and motor. Both approaches resulted in a 24% and 46% increase in the TMS penalty in fuel burn compared to the design that solely considering cruise condition, respectively. The assessment of the designed aircraft systems, integrating the TMS for the considered test cases, revealed that the liquid-cooling TMS designed at cruise condition with Approach B emerged as the optimal design, showcasing a 42% improvement in fuel burnt per payload compared to the air-cooling TMS at the mission level.
The Role of the Working Fluid and Nonideal Thermodynamic Effects on Performance of Gas-Lubricated Bearings
Authors: de Waart Wessel , Pini Matteo
Published: October 2024

Small-scale turbomachinery operating at high rotational speed is a key technology for increasing the power density of energy and propulsion systems. A notable example is the turbine of an organic Rankine cycle turbogenerator for thermal recuperation from prime engines and industrial processes. Such systems typically operate with organic compounds characterized by complex molecular structures to allow the design of efficient fluid machinery and flexibility in matching the heat source and sink temperature profiles. Gas-lubricated bearings are considered advantageous compared to traditional oil-lubricated rolling element bearings for supporting the turbine rotor, enabling greater machine compactness and reduced complexity, and avoiding contamination of the working fluid. In certain operating conditions, however, the lubricant of the gas bearing is in thermodynamic states near the saturated vapor line or in the vicinity of the fluid critical point, whereby nonideal effects are relevant and may affect bearing performance. This work investigates the physics of thin film flows in gas bearings operating with fluids made by complex molecules. The influence of nonideal thermodynamic effects on gas bearing performance is discussed by analysis of the fluid bulk modulus. Reduced values of the nondimensional bulk modulus near the critical point or saturated vapor line decrease bearing performance. The main parameter characterizing the influence of molecular complexity on bearing performance is shown to be the acentric factor. For complex fluids with large acentric factors, the impact of nonideal thermodynamic effects on nondimensional bearing load capacity and rotor-dynamic characteristics is less pronounced.
A Static/Dynamic Coupled Harmonic Balance Method for Dry Friction Systems Containing Rigid Body Modes
Authors: Fan Yu , Liu Jiale , Wu Yaguang , Wu Jian , Shen Qingyang , Zhang Dayi
Published: October 2024

A harmonic balance method for underconstrained dry friction systems containing rigid body modes (HBM-RBM) is proposed. This method aims to overcome the encountered obstacle when applying the harmonic balance method to turbine blades damped by underplatform dampers (UPDs). The inspiration for HBM-RBM comes from the free interface modal synthesis method. The key innovation involves deriving the elastic inversion of the singular stiffness matrix through the elimination of rigid body modes. In this way, the general HBM framework can be adopted, and the frequency response of underconstrained dry friction systems can be solved in a static/dynamic coupled manner. The accuracy and efficiency are both verified on a lumped parameter model and a finite element model of turbines with UPDs from a real gas turbine. A comparative study between the HBM-RBM and the commonly adopted way of imposing artificial grounding springs (HBM-AGS) is conducted. Results demonstrate that the HBM-RBM holds a significant advantage over HBM-AGS, as it eliminates the need for artificial grounding springs (AGS) and avoids the necessity for numerous trial cases to determine AGS stiffness.
V-Spline Design for Enhanced Performance in Turbine Blade Internal Cooling
Authors: Say Symus , Dhaker Adamya Singh , Chow Wai Tuck
Published: October 2024

Past experiments have consistently shown that V-shaped rib turbulators are among the best in heat transfer performance. While there is literature on the V rib design in various experimental studies, there is no literature that shows the V rib design applied on any current turbine blades. Instead, the straight and angled rib design are used. The V rib only offers a marginally better heat transfer performance over the angled rib, but it has a severe stress concentration at the rib tip. In this research, multiple design augmentations were analyzed, with the addition of a spline at the center of the V exhibiting alleviation of the tip stress concentration. The results show that the presence of the spline not only resolves the fatigue issues but also increases the heat transfer performance by 4.3% and 8.2% against the V rib and angled rib design, respectively. With a better heat transfer performance, the creep analysis shows that the turbine blade with a V-spline rib design can operate at temperatures 203 °C hotter than an angled rib at the same fluid power. Given the dependence of engine thermal efficiency on turbine inlet temperature, this simple design shows good potential for heat transfer augmentation.
Numerical Modeling of Fish Cage Structural Responses in Regular and Irregular Waves Using Modified XPBD
Authors: Wen Xueliang , Ong Muk Chen , Cheng Hui
Published: October 2024

The structural response of gravity-type fish cages in waves and currents is numerically investigated. A Morison model is adopted to compute the hydrodynamic forces acting on the net ropes and a screen model is used to compute the hydrodynamic forces on the net twines. The irregular waves are created based on the JONSWAP wave spectrum. The structure of the aquaculture nets is modeled using a modified extended position-based dynamics (XPBD) algorithm, which was first used in the simulations of cloth and other flexible bodies in games. The proposed method is effectively validated against the published experiment data to ensure its accuracy and reliability. The static response of the fish cage at various current speeds and the dynamic responses of the fish cage in regular and irregular waves are analyzed. Results show that the volume of the investigated fish cage is reduced by 30% in a current with a speed of 0.5 m/s. The tension at the bottom net can reach about 1.8 times of maximum tension of the case without current. In the regular or irregular waves, the drag force of the fish cage is higher than that in a uniform flow with the same current speed and the fish cage volume decreases. The increase in drag force rises from the coupling between the waves and currents. Therefore, the hydrodynamic model including the regular and irregular modeling, Morison model, and screen model is successfully implemented into the framework of the present modified XPBD algorithm to provide the structural response of fish cages in waves and currents.
Thermal Exploration of Combined Rectangular and Semi-Circular Artificial Ribs in the Flow Regime of Solar Air Heater: A Computational and Experimental Approach
Authors: Newar Pranjal Prasad , Das Biplab
Published: October 2024

A roughened solar air heater is developed numerically and experimentally with a novel roughness in the absorber. The roughness incorporated is a combination of rectangular and semi-circular ribs. The analysis is done to improve the thermal characteristics considering two cases. Type A with ribs placed above the absorber and Type B with ribs placed below it. Several operating parameters are investigated including heat flux, Reynolds number (Re), relative obstacle relative height (h/H) ranging from 400 W/m2 to 1000 W/m2, 4000 to 10,000, and 0.4 to 1.0, respectively. The relative pitch is kept constant at 15 mm. The governing equations are simulated employing the renormalization group k–ε turbulence flow model. The results indicated that both Type A and Type B achieved significant improvements over the smooth duct. Type A exhibited a maximum Nusselt number of 4.24, while Type B achieved 3.93 in comparison with smooth duct at Re of 10,000, respectively. The thermal enhancement factor (TEF) ranges from 1.32 to 1.79 for Type A and 1.26 to 1.69 for Type B at a heat flux intensity of 1000 W/m2. Also at a relative height of 1.0, Type A demonstrated the highest TEF of 1.79 at Re = 10,000 and provided a maximum exergy efficiency of 11.2%.
Fabrication-related impurity study of thin superconducting Al films using x-ray absorption spectroscopy
Authors: Bhandari Ghadendra B. , Stevenson Thomas R. , Barrentine Emily M. , Hess Larry A. , Holcomb Mikel B.
Published: October 2024

Superconducting aluminum thin films are integral to many astrophysics detector applications. Using x-ray absorption spectroscopy (XAS), we have studied the residues and adsorbates created during various standard lithography and etch steps, which are commonly used to pattern thin aluminum films into device structures. We have observed the formation of aluminum oxide as α-Al2O3 and aluminum fluoride as β-AlF3. We have observed correlations between these XAS signatures and the Al film’s microwave loss due to two-level systems. This study, which guides the way for future device optimization, further explores the chemical impact of different process steps, including standard silicon substrate wafer cleaning processes, sulfur-hexa-fluoride plasma etching, passivation with a fluorocarbon, and exposure to photoresist adhesion promoters during the lithography process with the help of control samples.
Effect of post-deposition annealing on crystal structure of RF magnetron sputtered germanium dioxide thin films
Authors: Abed Ahmad Matar , Peterson Rebecca L.
Published: October 2024

In this work, we demonstrate the growth and phase stabilization of ultrawide bandgap polycrystalline rutile germanium dioxide (GeO2) thin films. GeO2 thin films were deposited using RF magnetron sputtering on r-plane sapphire (Al2O3) substrates. As-deposited films were x-ray amorphous. Postdeposition annealing was performed at temperatures between 650 and 950 °C in an oxygen or nitrogen ambient. Annealing at temperatures from 750 to 950 °C resulted in mixed-phase polycrystalline films containing tetragonal (rutile) GeO2, hexagonal (α-quartz) GeO2, and/or cubic (diamond) germanium (Ge). When nitrogen was used as the anneal ambient, mixed GeO2 phases were observed. In contrast, annealing in oxygen promoted stabilization of the r-GeO2 phase. Grazing angle x-ray diffraction showed a preferred orientation of (220) r-GeO2 for all crystallized films. The combination of O2 annealing and O2 flux during growth resulted in r-GeO2 films with highly preferential alignment. Using electron microscopy, we observed an interfacial layer of hexagonal-oriented GeO2 with epitaxial alignment to the (11¯02) Al2O3 substrate, which may help stabilize the top polycrystalline r-GeO2 film.
Isotropic atomic layer etching of MgO-doped lithium niobate using sequential exposures of H2 and SF6/Ar plasmas
Authors: Chen Ivy I. , Solgaard Jennifer , Sekine Ryoto , Hossain Azmain A. , Ardizzi Anthony , Catherall David S. , Marandi Alireza , Renzas James R. , Greer Frank , Minnich Austin J.
Published: October 2024

Lithium niobate (LiNbO3, LN) is a ferroelectric crystal of interest for integrated photonics owing to its large second-order optical nonlinearity and the ability to impart periodic poling via an external electric field. However, on-chip device performance based on thin-film lithium niobate (TFLN) is presently limited by propagation losses arising from surface roughness and corrugations. Atomic layer etching (ALE) could potentially smooth these features and thereby increase photonic performance, but no ALE process has been reported for LN. Here, we report an isotropic ALE process for x-cut MgO-doped LN using sequential exposures of H2 and SF6/Ar plasmas. We observe an etch rate of 1.59±0.02 nm/cycle with a synergy of 96.9%. We also demonstrate that ALE can be achieved with SF6/O2 or Cl2/BCl3 plasma exposures in place of the SF6/Ar plasma step with synergies of 99.5% and 91.5%, respectively. The process is found to decrease the sidewall surface roughness of TFLN waveguides etched by physical Ar+ milling by 30% without additional wet processing. Our ALE process could be used to smooth sidewall surfaces of TFLN waveguides as a postprocessing treatment, thereby increasing the performance of TFLN nanophotonic devices and enabling new integrated photonic device capabilities.
A theoretical model of excess attenuation of acoustic signals propagating under cracked sea-ice landscapes
Authors: Alvarez Alberto
Published: October 2024

The Arctic sheet is transitioning from a continuous cover of thick multi-year ice to a fragmented landscape of thin young ice. If the type of acoustic transmission allows repetitive interaction of rays with the sea surface, in the fragmented scenario acoustic rays will undergo a random sequence of reflections from water or sea-ice interfaces. Calm sea conditions in the water channels between the ice floes (leads) and the smooth, flat surface of the young ice bottom reduce scattering due to interface roughness, resulting only in scattering due to inhomogeneity in surface reflectivity. Using an idealized framework, this study investigates the extent to which the mid- to high-frequency underwater acoustic propagation is altered due to repetitive interactions of acoustic signals with a sea surface consisting of a random distribution of ice sheets and leads. An expression for the coherent field (the acoustic field averaged over an ensemble of realizations of sea-ice distributions) was derived from theory. Any deviation from a homogeneous surface condition (either by randomly adding ice slabs in a free ice surface or by including leads in a fully ice-covered sea surface) leads to an excess attenuation of the coherent field. Results are validated by numerical simulations.
Binaural fusion: Complexities in definition and measurement
Authors: Reiss Lina A. J. , Goupell Matthew J.
Published: October 2024

Despite the growing interest in studying binaural fusion, there is little consensus over its definition or how it is best measured. This review seeks to describe the complexities of binaural fusion, highlight measurement challenges, provide guidelines for rigorous perceptual measurements, and provide a working definition that encompasses this information. First, it is argued that binaural fusion may be multidimensional and might occur in one domain but not others, such as fusion in the spatial but not the spectral domain or vice versa. Second, binaural fusion may occur on a continuous scale rather than on a binary one. Third, binaural fusion responses are highly idiosyncratic, which could be a result of methodology, such as the specific experimental instructions, suggesting a need to explicitly report the instructions given. Fourth, it is possible that direct (“Did you hear one sound or two?”) and indirect (“Where did the sound come from?” or “What was the pitch of the sound?”) measurements of fusion will produce different results. In conclusion, explicit consideration of these attributes and reporting of methodology are needed for rigorous interpretation and comparison across studies and listener populations.
IFN-γ primes bone marrow neutrophils to acquire regulatory functions in severe viral respiratory infections
Authors: Creusat Florent , Jouan Youenn , Gonzalez Loïc , Barsac Emilie , Ilango Guy , Lemoine Roxane , Soulard Daphnée , Hankard Antoine , Boisseau Chloé , Guillon Antoine , Lin Qiaochu , de Amat Herbozo Carolina , Sencio Valentin , Winter Nathalie , Sizaret Damien , Trottein François , Si-Tahar Mustapha , Briard Benoit , Mallevaey Thierry , Faveeuw Christelle , Baranek Thomas , Paget Christophe
Published: October 2024

Neutrophil subsets endowed with regulatory/suppressive properties are widely regarded as deleterious immune cells that can jeopardize antitumoral response and/or antimicrobial resistance. Here, we describe a sizeable fraction of neutrophils characterized by the expression of programmed death-ligand 1 (PD-L1) in biological fluids of humans and mice with severe viral respiratory infections (VRI). Biological and transcriptomic approaches indicated that VRI-driven PD-L1
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neutrophils are endowed with potent regulatory functions and reduced classical antimicrobial properties, as compared to their PD-L1
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counterpart. VRI-induced regulatory PD-L1
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neutrophils were generated remotely in the bone marrow in an IFN-γ–dependent manner and were quickly mobilized into the inflamed lungs where they fulfilled their maturation. Neutrophil depletion and PD-L1 blockade during experimental VRI resulted in higher mortality, increased local inflammation, and reduced expression of resolving factors. These findings suggest that PD-L1
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neutrophils are important players in disease tolerance by mitigating local inflammation during severe VRI and that they may constitute relevant targets for future immune interventions.