bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical relevance of NFYA splice variants in patients with acute myeloid leukaemia undergoing intensive chemotherapy
Authors: Yang Yi‐Tsung , Yao Chi‐Yuan , Kao Chein‐Jun , Chiu Po‐Ju , Lin Ming‐En , Hou Hsin‐An , Lin Chien‐Chin , Chou Wen‐Chien , Tien Hwei‐Fang
Published: August 2024

Aberrant alternative splicing (AS) contributes to leukemogenesis, but reports on the clinical and biological implications of aberrant AS in acute myeloid leukaemia (AML) remain limited. Here, we used RNA‐seq to analyse AS in AML cells from 341 patients, comparing them to healthy CD34+ haematopoietic stem cells (HSCs). Our findings highlight distinct AS patterns in the nuclear transcription factor Y subunit alpha (NFYA) gene, with two main isoforms: NFYA‐L (Long) and NFYA‐S (Short), differing in exon 3 inclusion. Patients with lower NFYA‐L but higher NFYA‐S expression, termed NFYA‐S predominance, displayed more favourable characteristics and better outcomes following intensive chemotherapy, regardless of age and European LeukemiaNet risk classification, compared to those with higher NFYA‐L but lower NFYA‐S expression, termed NFYA‐L predominance. The prognostic effects were validated using The Cancer Genome Atlas cohort. Transcriptome analysis revealed upregulated cell cycle genes in NFYA‐S predominant cases, resembling those of active HSCs, demonstrating relative chemosensitivity. Conversely, NFYA‐L predominant cases, as observed in KMT2A‐rearranged leukaemia, were associated with relative chemoresistance. NFYA‐S overexpression in OCI‐AML3 cells promoted cell proliferation, S‐phase entry and increased cytarabine sensitivity, suggesting its clinical and therapeutic relevance in AML. Our study underscores NFYA AS as a potential prognostic biomarker in AML.
Endoscopic hand suturing has the potential to reduce bleeding after gastric endoscopic submucosal dissection in patients on antithrombotic agents: Multicenter phase II study
Authors: Goto Osamu , Morita Yoshinori , Takayama Hiroshi , Hirasawa Kingo , Sato Chiko , Oyama Tsuneo , Takahashi Akiko , Abe Seiichiro , Saito Yutaka , Ono Hiroyuki , Kawata Noboru , Otsuka Toshiaki , Iwakiri Katsuhiko
Published: August 2024

Objectives

The risk of postoperative bleeding is high after gastric endoscopic submucosal dissection (ESD) in patients continuously treated with antithrombotic agents (ATAs). The effectiveness of endoscopic hand suturing (EHS) on bleeding after gastric ESD was investigated in patients at high risk of delayed bleeding.

Methods

Patients with neoplasms ≤2 cm who underwent gastric ESD and continued to receive perioperative ATAs were enrolled in this multicenter phase II study. The mucosal defect was closed with EHS after removing the lesion. Postoperative bleeding rate was assessed for 3–4 postoperative weeks as a primary outcome measure. The technical success of EHS and adverse events were also assessed. Based on expected and threshold postoperative bleeding rates of 10% and 25%, respectively, we aimed to include 48 patients in the study.

Results

A total of 49 patients were enrolled in the study, and 43 patients were finally registered as the per‐protocol set. The postoperative bleeding rate was 7.0% (3/43 patients; the upper limit of one‐sided 95% confidence interval [CI], 17.1% and 97.5% CI, 19.1%). The upper limits of the CI were below the threshold value (25%), and the postoperative bleeding rate was below the expected value (10%). The technical EHS success rate, closure maintenance rate on postoperative day 3, and postoperative subclinical bleeding rate were 100%, 83%, and 2%, respectively. No severe adverse events related to EHS were observed.

Conclusions

Endoscopic hand suturing may prevent postoperative bleeding in patients undergoing gastric ESD while being treated continuously with ATAs (UMIN000038140).
Differences in fisher demographics and fishing behaviour from concurrent phone‐recall and smartphone app surveys of recreational angling in south‐western Australia
Authors: Trinnie Fabian I. , Ryan Karina L.
Published: August 2024

Traditional methods for collecting robust samples of recreational effort and catch data from offsite mail or telephone surveys are becoming increasingly difficult to obtain. Smartphone applications (apps) that allow recreational fishers to report their effort and catch are a potentially viable data collection tool, but may be biased. We evaluated demographics, effort, and catch of freshwater anglers in south‐west Western Australia by comparing independent data from concurrent phone‐recall and app‐diary surveys for a 12‐month period in 2017–2018. Survey modes differed, with higher proportions of app respondents angling in freshwater and being avid anglers. For both survey modes, unweighted mean effort (days fished) was higher in dams than rivers, but was higher from the phone‐recall survey for dams and rivers. The unweighted distribution of kept and released catches (number of fish per angler) of rainbow trout (Oncorhynchus mykiss) and redfin (Perca fluviatilis) were similar between survey modes, with higher retention of redfin and higher release of rainbow trout. Kept and released rates of freshwater cobbler (Tandanus bostocki) and brown trout (Salmo trutta) were less common in both survey modes. Lower response rates and higher survey participation by avid anglers (≥20 days per year) from the app‐diary survey may bias survey data. Such bias needs to be addressed when using digital data collection methods, along with improving recruitment and retention of app participants.
Synthesis and Characterization of Metallic (Fe‐Ni, Fe‐Ni‐Si) Reference Materials for SIMS 34S/32S Measurements
Authors: Dalou Celia , Riguet Lenny , Villeneuve Johan , Tissandier Laurent , Rigaudier Thomas , Cividini Damien , Zollinger Julien , Paris Guillaume
Published: August 2024

Secondary ion mass spectrometry (SIMS) is often used to determine the sulfur contents and isotope ratios of metallic alloys in meteorites or high‐pressure experimental samples. However, SIMS analyses involve calibration and the determination of instrumental mass fractionation in reference materials with a matrix composition similar to that of the unknown samples. To provide metallic reference materials adapted to S measurements via SIMS, we synthesised a series of twenty‐eight alloys comprising four FeNi(±Si) compositions (Fe95Ni5, Fe90Ni10, Fe80Ni20, and Fe80Ni15Si5) with S contents varying from 100 μg g−1 to 4 g/100g using the “melt spinning” method, which guarantees that the metal alloys are rapidly quenched at ~ 106 K s−1. Sulfur contents were determined at the Service d'Analyse des Roches et Minéraux at the CRPG and absolute δ34S values were determined by multi‐collector ICP‐MS (MC‐ICP‐MS, ThermoScientific Neptune) and isotope ratio mass spectrometry (Thermoscientific Delta V). A δ34S value of 16.01 ± 0.31‰ was consistently obtained using the MC‐ICP‐MS, which was indistinguishable of the δ34S value of the FeS starting material (15.95 ± 0.08‰). It suggests that S did not undergo isotopic fractionation during the melting process. Of fifteen samples containing ≤ 5000 μg g−1 S, SIMS measurements with 15‐μm‐diameter spots were repeatable to within 10% relative (1 standard deviation, 1s) for S contents and 2‰ for δ34S values. However, samples containing > 5000 μg g−1 S showed FeNi–FeS immiscibility, leading to minor dispersion of the S mass fractions and δ34S values. No matrix effect was observed for Fe‐Ni, Si, or S contents in terms of the calibration curves and instrumental mass fractionation. We ultimately recommend eight samples as reliable reference materials for S isotopic measurements by SIMS, which we can share worldwide with other laboratories.
Multiplicities and fluidity in the networked relationships of migrant academics in Britain
Authors: Aydemir Mücahit
Published: August 2024

Increasing internationalization and marketization of higher education, global research collaboration, and staff mobility place academics' networking practices at the centre of higher education systems. Migrant academics are conceptualized with different network types including personal, local and transnational family and friendship networks. However, this research aims to understand the boundaries between different types of participants' networked relationships. The data of this paper comes from a larger research project on transnational family relationships of migrant academics conducted between 2018 and 2022. Life story interviews with 45 migrant academics from 27 different national backgrounds working at British universities were conducted. Additionally, sociogram maps are used as embedded in qualitative interviews. Migration background (as European or non‐European countries); gender; age; the length of the stay in the UK; academic position/contract type; annual income level and marital/relationship status were considered while forming the sample. The findings reveal that network forms and structures do not determine the resources and benefits of relationships; rather, individuals' actions over a time period and the meanings they attribute shape the positions of an alter (other actors that the focal person have connection with) within the personal network structure. As such, actions and meanings regarding those actions can bring one forward or backward in the personal network hierarchy. The boundaries regarding the content of these networks are usually blurred in relation to time, relationality and human agency attributing specific sets of meanings to certain relationships. The findings of this research translate into specific contributions to the discussions in migration and social network research. That is, research findings emphasized that different types of networks shaping participants' lives and migratory experiences are far from being stable and fixed, rather, they are characterized by being transmissive and dynamic. It is revealed that none of the network categories are homogenous, stable and fixed in terms of the content of the relationships. This adds to Emirbayer and Goodwin's (1994) discussions around the ‘form’ and the ‘content’ of networks. This paper underscores the significance of the historical settings, dynamism and the content of each relationship in understanding individual networks.
Infective endocarditis outcomes at a tertiary hospital in Western Australia: a retrospective cohort study from 2016 to 2021
Authors: Lawson Eli , Jacques Angela , Italiano Claire , Robinson James O.
Published: August 2024

Background

Infective endocarditis (IE) is a severe infection with considerable mortality. It is associated with geographical variation, complicating diagnosis and treatment of patients in a standardised manner.

Aim

To evaluate the characteristics and management outcomes of patients with IE in Royal Perth Hospital (RPH).

Methods

A single‐centre, retrospective cohort study. Data were collected from medical records of 131 patients with a diagnosis of IE admitted to RPH between 2016 and 2021.

Results

Eighty‐four patients with definite IE were included for analysis. The median age of patients was 51.5 years and 77.4% were male. Compared to the general Australian population, there was disproportionately greater representation of Indigenous Australians (21.4%), those with a history of injecting drug use (IDU) (27.4%), rheumatic heart disease (14.3%) and previous IE (13.1%). The most commonly affected valve was the mitral valve in 46.4% of patients, and the most common pathogen was Staphylococcus aureus in 47.6% of patients. Twelve‐month mortality was 16.7%, with significantly increased mortality in those treated non‐surgically (25.6% vs 7.3%, P = 0.025). Factors associated with undergoing surgery included the presence of aortic valve disease, perivalvular extension of infection and infection with Enterococcus faecalis, whereas IDU, tricuspid valve disease and S. aureus infection were associated with non‐surgical management. Adherence to multidisciplinary team review was 75.0%, and surgical management was performed in 70.7% of patients meeting an indication for surgery.

Conclusion

IE mortality rates remain high, particularly in patients who do not undergo surgical management. Streamlined MDT assessment and referral for surgical management where appropriate is necessary to improve outcomes.
Acute leptospirosis in horses: A retrospective study of 11 cases (2015‐2023)
Authors: Ramsay Lynette , Eberhardt Christina , Schoster Angelika
Published: August 2024

Background

Reports of leptospirosis in horses are limited.

Objectives

To describe the clinical and diagnostic findings of acute systemic leptospirosis in horses.

Animals

Eleven client‐owned horses presented to an equine hospital because of acute onset of disease between 2015 and 2023.

Methods

Retrospective case series. Horses diagnosed with leptospirosis by 1 or more of urine PCR, serologic microscopic agglutination test (MAT), and histopathology.

Results

Common clinical signs included lethargy (10), anorexia (10), fever (9), tachypnea (9), abnormal lung sounds (9), and epistaxis (6). Acute kidney injury was present in all cases. Evidence of pulmonary hemorrhage and liver disease was found in 8 (73%) and 6 (55%) horses, respectively. In 6 (55%) horses, kidneys, lungs, and liver were affected. Urine quantitative polymerase chain reaction for detection of pathogenic Leptospira spp. was positive in 6 (55%) cases. On serology Leptospira interrogans serovar Australis, Autumnalis, and Bratislava accounted for 86% of all titers ≥1 : 800. Overall case fatality rate was 4/11 (36%). Main findings on necropsy were tubular necrosis, interstitial nephritis, hemorrhage in the alveoli, pulmonary edema, periportal hepatitis and necrosis, cholestasis, and cholangitis.

Conclusions and Clinical Importance

Leptospirosis should be considered as a differential diagnosis in horses with evidence of acute systemic inflammation and acute renal injury, epistaxis, or hepatic disease. For increased likelihood of identifying positive cases, both MAT serology and urine PCR should be performed.
Sherlock Holmes, the Chronologists, and the Cocaine
Authors: Nelles William
Published: August 2024

A distinctive school of “Sherlockian scholarship” has grown up around the Sherlock Holmes series, one corollary of which is that a consistent chronology of Holmes's life can be assembled by cross‐referencing the datable events in the stories. Holmes's use of cocaine throughout the series provides a test case for analyzing the consequences of the Chronologists' emphasis on the biographical sequences they reconstruct from the texts.
Analysing Stylistic Differences between Orchestras: an Empirical Study of the ‘Viennese Rhythm’ in the Vienna Philharmonic's Recordings of The Blue Danube
Authors: Zhou Danny , Yang Jian
Published: August 2024

Performances of the same piece can differ from one another in many ways. Nevertheless, few scholars have attempted to investigate stylistic differences between orchestras. This article explores in what ways and to what extent the Vienna Philharmonic – an orchestra widely regarded as one of the world's most distinctive – performs metrical rhythm differently from other professional orchestras. It presents findings from an empirical analysis of the timing of the ‘Viennese rhythm’, a rhythmic pattern characterised by the shortening of the first beat and the lengthening of the second in the performance of Viennese waltzes. The methodology employs computer‐assisted techniques to analyse beat lengths in 30 recordings of two excerpts from The Blue Danube. The results indicate that the Vienna Philharmonic tends to use the Viennese rhythm more frequently and to a greater extent than other professional orchestras. This tendency enhances expressivity and heightens the sense of dance motion. As a result, in the Vienna Philharmonic's performances, metrical rhythm is far more than mechanical reproduction of a preordained set of time divisions, becoming instead a spontaneous expressive device which creates the sensuous embodiment of a durational process. This research shows that the way in which the Vienna Philharmonic plays metrical rhythm forms an integral part of their style, regardless of conductor. The article offers new insights into stylistic differences between orchestras and paves the way for a deeper investigation of performance styles in orchestral music.
Efficacy and safety of duodenal–jejunal bypass liner for obesity and type 2 diabetes: A systematic review and meta‐analysis
Authors: Chen Wenhui , Feng Jia , Dong Shiliang , Guo Jie , Zhou Fuqing , Hu Songhao , Hu Ruixiang , Wang Cunchuan , Ma Yi , Dong Zhiyong
Published: August 2024

This study aimed to evaluate the efficacy and safety of duodenal–jejunal bypass liner (DJBL) for obesity and type 2 diabetes mellitus. A comprehensive search of electronic databases was conducted up to September 15, 2022. Thirty studies involving 1751 patients were included. At 12 months post‐implantation, the reduction in body mass index (BMI) was 4.8 kg/m2 (95% CI 4.1, 5.5), with an excess weight loss of 41.3% (95% CI 33.4%,49.2%) and a total weight loss of 13.1% (95% CI 10.1%, 16.0%). Significant decrease was observed in HbA1c and fasting glucose, with a standardized mean difference of − 0.72 (95% CI − 0.95, − 0.48) and − 0.62 (95% CI − 0.82, − 0.42), respectively. However, these improvements in weight loss and glycemic control were only partially sustained after explantation. In situ, DJBL significantly improves blood pressure and lipid levels. The pooled early removal rate was 19%, and the incidence of severe adverse events was 17%, including device migration (6%), gastrointestinal hemorrhage (4%), device obstruction (4%), and hepatic abscess (2%). DJBL offers significant improvement in weight loss and glycemic control, as well as cardiovascular parameters while in situ. Further studies are warranted to better understand the long‐term efficacy and safety of DJBL. The benefits of DJBL need to be carefully weighed against the risks in clinical decision‐making.
Deciphering interleukin‐18 in diabetes and its complications: Biological features, mechanisms, and therapeutic perspectives
Authors: Gui Runlin , Ren Yuanyuan , Wang Zhen , Li Yang , Wu Chengsong , Li Xiaofang , Li Man , Li Yujia , Qian Lu , Xiong Yuyan
Published: August 2024

Interleukin‐18 (IL‐18), a potent and multifunctional pro‐inflammatory cytokine, plays a critical role in regulating β‐cell failure, β‐cell death, insulin resistance, and various complications of diabetes mellitus (DM). It exerts its effects by triggering various signaling pathways, enhancing the production of pro‐inflammatory cytokines and nitric oxide (NO), as well as promoting immune cells infiltration and β‐cells death. Abnormal alterations in IL‐18 levels have been revealed to be strongly associated with the onset and development of DM and its complications. Targeting IL‐18 may present a novel and promising approach for DM therapy. An increasing number of IL‐18 inhibitors, including chemical and natural inhibitors, have been developed and have been shown to protect against DM and diabetic complications. This review provides a comprehensive understanding of the production, biological functions, action mode, and activated signaling pathways of IL‐18. Next, we shed light on how IL‐18 contributes to the pathogenesis of DM and its associated complications with links to its roles in the modulation of β‐cell failure and death, insulin resistance in various tissues, and pancreatitis. Furthermore, the therapeutic potential of targeting IL‐18 for the diagnosis and treatment of DM is also highlighted. We hope that this review will help us better understand the functions of IL‐18 in the pathogenesis of DM and its complications, providing novel strategies for DM diagnosis and treatment.
Genome‐Wide Association Studies Predicted Drought Stress Occuring at Anthesis and Post‐Anthesis Stages in Novel Diverse Germplasm of Bread Wheat (Triticum aestivum)
Authors: Shokat Sajid , Arif Mian Abdur Rehman , Favero Bruno Trevenzoli , Bhatnagar‐Mathur Pooja , Lopes Marta S. , Liu Fulai , Singh Sukhwinder
Published: August 2024

This study employed genome‐wide association studies (GWAS) to identify the crucial marker–trait associations (MTAs) for agronomic and physiological traits in bread wheat grown under full irrigation and 40% reduced irrigation. One hundred twenty‐four genotypes derived from three‐way crosses of landraces and synthetic bread wheat were evaluated for 2 years in the field conditions of CIMMYT Obregon, Mexico. Irrigation was not provided at anthesis and post‐anthesis stage for the drought treatment, and data of 12 traits were recorded. Most of the traits were reduced significantly under drought conditions except for vigour, wax and spike length (SL); genotypes were significantly different for the eight traits except for days to heading (DTH), number of grains spike−1 (NGS), normalized difference in vegetation index (NDVI) and canopy temperature depression (CTD); and differences were also significant for five traits between the years. Moreover, GY was significantly and negatively correlated with wax and CTD. Our GWAS results indicated 117 significant (p ≤ 0.001) MTAs distributed on all the wheat chromosomes except chromosomes 4B and 4D explaining 10%–21.5% of the phenotypic variation of the corresponding traits. Moreover, 22 MTAs were recorded for grain yield and explaining the phenotypic variations up to 14.7% with one common association under both irrigated and drought conditions. Additionally, we also identified the associations for NDVI, CTD and SL at chromosome 1B, suggesting that genotypes are sustaining superior grain yield through better values of traits like NDVI, CTD, and SL under the challenging conditions of anthesis and post‐anthesis drought stress.
The Propagation and Reduction of Uncertainty Left Unquantified by Confidence Intervals, p-Values, Neural Network Predictions, Posterior Distributions, and Other Statistical Results
Authors: Bickel David R.
Published: August 2024

In the use of statistical models to analyze data, there is not only the uncertainty quantified by the models but also uncertainty about which models are adequate for some purpose, such as weighing the evidence for or against a hypothesis of scientific interest. This paper provides methods for propagating such unquantified uncertainty to the results under a unified framework of adequate model averaging. Specifically, the weight of each model used in the average is the probability that it is the most useful model. To allow for the case that none of the models considered would be useful, a catch-all model is included in the model average at a different level of the hierarchy. The catch-all model is the vacuous model in imprecise probability theory, the model that puts no restrictions on the probabilities of statements about the unknown values of interest. That enables defining the proportion of the uncertainty left unquantified by a model as the probability that it is inadequate in the sense of being less useful than the catch-all model. A lower bound for the proportion of unquantified uncertainty of the averaged model decreases as more models are added to the average.
Accuracy of Steady Pneumatic Probes in Unsteady Turbomachinery Flows
Authors: Widera Tim Sebastian , Patzer Bastian , Behre Stephan , Jeschke Peter
Published: August 2024

This study shows that no additional measurement error due to unsteadiness was detected, when measuring in periodic turbo-machinery flows at frequencies up to 5 kHz with steady, pneumatic probes.

An experiment was designed, which consisted of abstracted rotors placed in the jet of a free stream wind tunnel. Five steady and unsteady probes were compared in the periodic, turbomachinery-like wakes at Mach numbers up to 0.8. The impacts of unsteadiness, probe head size and shape, and distance between probe and rotor were systematically investigated at up to 90 operating points. Within the limits imposed by unsteady pressure transducers, the experiments demonstrated the absence of a frequency-dependent effect on the measurements by comparing the time-averaged measurements of identically shaped steady and unsteady probes.

Measurements with hemispherical five-hole probes of two sizes and kielhead probes at the same location deviated significantly due to different interaction with the upstream rotor. Distance variations between probe and rotor showed that each combination of probe and flow should be evaluated individually.

The study concludes that pneumatic probes offer a reasonable means to measure the mean flow downstream of a rotor, accurately reproducing time-averaged values. However, careful individual evaluation of probes is essential to minimise measurement uncertainty.
Analysis of the Inlet Recirculation Phenomenon in a High-Speed Industrial Centrifugal Compressor: Experimental and Computational Study
Authors: Ullah Tariq , Klüver Merle , Jaatinen-Värri Ahti , Turunen-Saaresti Teemu , Sobczak Krzysztof , Liskiewicz Grzegorz
Published: August 2024

This research paper presents an investigation of the local flow instability known as inlet recirculation in a high-speed industrial centrifugal compressor. This phenomenon might appear when a compressor operates at a lower than the design mass flow rate and approaches the surge line. The study combines experimental measurements with a 3D steady-state Reynolds-Averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) model using the k-ω Shear Stress Transport turbulence model. The single-passage CFD model was validated against the experimental data for the design speed line. A detailed mesh independence study was conducted to estimate the discretization uncertainty and evaluate grid refinement at the design point. The results indicate that as the mass flow rate decreases and approaches the surge line, the inlet recirculation phenomenon is observed. The inlet recirculation is quantitatively analyzed, and the blockage it causes is determined. It was found that inlet recirculation can account for approximately 9% of the compressor mass flow rate and can block up to 38% of the flow area at the impeller inlet. Also, the expansion of the inlet recirculation zones was growing in two phases, showing significant radial and streamwise growth as the inlet blockage increased. For lower inlet blockage, the radial growth dominated the streamwise growth. While the streamwise growth increased significantly with relatively constant radial expansion at the higher inlet blockage.
Hydrogen Co-Firing Demonstration at Constellation Hillabee Siemens Energy SGT6-6000g Power Plant
Authors: Harper James , Gibeaut Duane , Lozier Mark , Sake Richard , Wolf Thorsten , Noble David R.
Published: August 2024

Gas Turbines will need to reduce CO2 emissions and prove their flexibility based on market needs and new proposed rules [2]. Economically, utilizing existing gas turbine assets to meet these requirements will be of great benefit as compared to building new turbines. Even better, determining the lowest cost least intrusive upgrades required is of great interest to power producers. The demonstration described here was conducted on one (1) GT unit at the Constellation Hillabee power plant (Siemens Energy SGT6-6000G 2x1 configuration) which doubled the mass flow of hydrogen of previous record-breaking DLN demonstrations. The testing was done on an unaltered, existing GT asset, which provides great value for those GTs which are already providing power using natural gas. The demonstrated hydrogen blending percentage of 38.8% (resulting in approximately 18% reduction in CO2 emissions) proved the system capable of meeting the first BSER goals set forth in recent proposed US EPA gas turbine rules. Such demonstrations are of critical importance as they show the inherent capability to meet reduced carbon power generation requirements without more significant cost outlays. This report documents the evaluation, preparation, execution, and results from this demonstration testing. The results are provided for the gas turbine community to use as insight into the capability and flexibility of existing assets to meet the future demands of reduced carbon power generation. Specific information around safety, reliability, emissions, and operability are discussed to provide context around existing asset capability.
Superposition of Overall Cooling Effectiveness on a Turbine Blade Leading Edge
Authors: Hopkins Bailey W. , Rutledge James L.
Published: August 2024

Increasingly harsh turbine environments necessitate the design of more advanced cooling techniques as well as prediction of those cooling schemes’ performance at engine conditions. For several decades, film cooling design has been accelerated through a low-order superposition of adiabatic effectiveness in order to quickly approximate the combined effect of multiple rows of cooling holes, the individual rows of which have already been characterized. While that legacy technique is able to approximately superpose the benefits of multiple rows of external film cooling holes, it is unable to superpose the added benefits of additional internal cooling features. This limitation of traditional film cooling superposition has been overcome with a new technique that allows superposition of overall effectiveness which is influenced by both external film cooling and internal cooling. In this paper, the new overall effectiveness superposition technique is evaluated in a turbine airfoil leading edge showerhead region. The superposition technique is shown to be effective at predicting the added benefit of an additional row of cooling holes in the leading edge region along with the associated internal cooling that accompanies the additional row of cooling holes. Special care must be taken, however, due to pressure gradients associated with the leading edge curvature.
Mechanical Performance and Material Characterization of Fused Filament Fabricated ABD 900 Superalloy
Authors: Siddiqui Sanna F. , Fandetti Dustin , Scott-Emuakpor Onome
Published: August 2024

The material extrusion additive manufacturing (MEAM)/metal fused filament fabrication (MFFF) process for metal 3D printing is actively being sought as a potentially viable manufacturing option for jet engine propulsion materials. Its low cost, safety/ease in part manufacturing and operation coupled with its potential to efficiently develop deployable ready structures, makes it an attractive option for manufacturing of nickel-based superalloys, compared to laser powder bed fusion (LPBF) additive manufacturing technologies. ABD®900 is a nickel-based superalloy with high strength and corrosion/oxidation resistance at extreme temperatures, which has gained interest in its potential to be additively manufactured through the LPBF technology and reported to yield enhanced mechanical performance at high temperatures as compared with existing nickel-based superalloys, such as LPBF Inconel 718. This novel study is of the first of its kind to report on the ambient tensile response/properties and fracture mechanics exhibited by FFF ABD®900 green test coupons, and to assess the structural integrity of green and sintered cubes through material characterization techniques. Preliminary research findings on green tensile coupons and cubes reveal presence of considerable interlayer delamination and interlayer voids/porosity, with crazing marks evident on sample surface of green tensile coupons. A wide distribution of powder particles sizes is apparent, with most retaining their circular geometry but elliptical/oblong geometry of powder particles evident as well. Upon completion of the initial sintering cycle of cube specimens, presence of warping and shrinkage are quantifiably evident. The concluding position on the initial sintering trial identifies a need for precise furnace controls and understanding of part temperature as it transitions from green to brown to complete part densification.
Experimental and Numerical Investigations of the Influence of Cavitation on the Head Drop Curves of Centrifugal Pumps
Authors: Kaya Mehmet , Ayder Erkan
Published: August 2024

Cavitation is a major problem in pump operation because this phenomenon may lead to hydraulic performance loss, increased noise levels, and various types of instabilities. Therefore, fast and robust calculation methods that the industry can confidently use to predict cavitation are being actively studied.

In the present work, the cavitation performance of pumps designed at two specific speeds is studied numerically and experimentally. Net positive suction head (NPSH) measurements for the pumps are performed over their operating ranges. Moreover, Q-NPSH3 and head drop curves are obtained for the pumps at metric specific speeds of 22.4 (rotating at 2950 rpm) and 12.5 (rotating at 1475 rpm), respectively. Cavitation is visualized by a stroboscopic light source and recorded at various NPSH levels for three different flow rates. The relationship between cavity length and head drop is revealed.

The Singhal [18] model, a homogeneous mixture cavitation model, is typically used in numerical calculations. A turbulent viscosity correction for the multiphase calculations of cavitating flow around hydrofoils is proposed in the literature. In the present work, this correction is applied to modify the Singhal [18] cavitation model, and the head drop curve of the pump with ns = 22.4 is computed using this modified model. Consequently, the compatibility between the numerical and experimental results is found to improve. Accordingly, the cavitation calculations for the pump with ns = 12.5 are performed using the modified model. The computed cavitation structures at various points on the head drop curves are compared with experimental images. Geometrically similar forms are achieved.
High Effectiveness Tip Cooling Using Inclined Slots
Authors: Mutekwa Macdonald , Vieira Joao , Farfaras Maximilian G. , Coull John D. , Bacic Marko , Ireland Peter T.
Published: August 2024

The tip of the High-Pressure Turbine (HPT) blade is critical for gas turbine performance. Hot gas leaking through the tip gap tends to oxidize and erode the blade, while generating significant aerodynamic loss. Squealer tips are often used to maximize efficiency, but the thin rims are thermally vulnerable and difficult to cool. The resultant degradation often limits engine life, turbine entry temperatures and thermal efficiency.

This work considers means to improve the cooling of squealer tips to minimize degradation. Compared to conventional, cylindrical-hole designs, a step-change improvement in cooling effectiveness can be achieved using near-tip slots. In this configuration, coolant is ejected in an approximately streamwise direction along the pressure side rim, cooling a large area with high effectiveness. Experiments characterizing cooling and aerodynamics are performed in a representative linear cascade on an inclined slot design developed to enhance manufacturability while retaining high cooling effectiveness. This design is shown to more than double the cooling effectiveness on the pressure side rim compared to a conventional discrete-hole baseline. Improved coolant shielding is retained for varying massflow rates, tip clearances, and density ratios. Aerodynamic measurements show that the slot design can outperform the baseline provided the coolant mass fraction between the slots is suitably optimized.
Predicting Dust Erosion in a Counter-Rotating Fan
Authors: Ghenaiet Adel
Published: August 2024

Counter-rotating fans (CRFs) become an attractive solution for the ventilation of tunnels and mines, but operate under particulate flows and suffer from serious erosion. This study aims to provide insights into the dynamics of ingested dust particles and erosion development. The computations used an in-house Lagrangian particle tracking code that implements the random walk algorithm and probabilistic models for the particles release positions, sizes, and rebound factors. The finite element method tracks particles through the mesh elements and provides exact the impacts and the conditions required to evaluate the local erosion rates. The pollutant is the Saharan dust, with finer-sized particles ranging from 0.1 to 100 microns, and concentration between 0.1–0.5 mg/m3, that was extended to 1–3 mg/m3 to simulate a mine atmosphere.

As a result, the front rotor (FR) exhibits impacts of high frequency, and thus erosion develops along the leading edge (LE) and extends over a large band from the blade suction side (SS) and upward to two-thirds of the blade pressure side (PS) and along the blade tip. On the other hand, the rear rotor (RR) exhibits similar patterns of erosion where the LE and the fore of the SS are more eroded, as well as the PS, which depicts a larger area of erosion. It seems that the erosion rate densities of RR are practically doubled, except for the upper region from the TE. The present results help to monitor the in-service lifetime of CRFs and select coatings to resist erosion.
Film Cooling Performance on Rotating Blade Leading Edge With Various Rotating Speed and Film Hole Structures
Authors: Jiang Yan , Huang Yi , Li Haiwang , Zhou Zhiyu , Xie Gang
Published: August 2024

The present study numerically investigated the effect of typical leading edge structural parameters on the film cooling characteristics under rotating conditions. The studied parameters included the blade rotating speed (400rpm, 600rpm and 800rpm), the number of each row of film holes (N = 9, 10 and 11), the injection angle (β = 20°, 30° and 40°) and the blowing ratio (M = 0.5, 0.75, 1 and 1.5). Results showed that the rotating speed had a great influence on the leading edge coolant outflow direction. Coolant basically deflected towards the suction side at 400rpm, flowed out to both sides at 600rpm, and almost separated from the leading edge surface and distributed in the middle of three rows of holes at 800rpm. Whereas, the number of holes had less effect on the film cooling performance. Increasing the number of holes could greatly improve the coverage rate of coolant on the leading edge surface. The film cooling effectiveness increased monotonously with the number of film holes, and that with 11 holes per row was improved by 3.8% and 6.7% compared to that with 10 and 9 holes per row at condition of 400rpm and M = 1.5, respectively. Moreover, the film cooling effectiveness on the leading edge increased with the decrease of the injection angle. Coolant in the case of holes with 20° injection angle had larger outlet area and showed better wall attachment, which resulted in wider and more uniform film distribution, so that performed the greatest film cooling effectiveness. And the effectiveness in the case of holes with 20° injection angle was 30.2% and 55.5% higher than that with 30° and 40° injection angle at condition of 600rpm and M = 1.5, respectively.
Energy and Economic Optimization of the Design and Operation of Hybrid Energy Plants Under Current and Future Economic Scenarios
Authors: Castorino Giulia Anna Maria , Losi Enzo , Manservigi Lucrezia , Pinelli Michele , Spina Pier Ruggero , Venturini Mauro
Published: August 2024

At present, renewable energy is commonly expected to be the main source to lead the green energy transition with the target of carbon neutrality. Despite the crucial importance of renewable energy sources, several issues still require the integration with traditional technologies.

Therefore, this paper investigates the design and operation of a Hybrid Energy Plant (HEP) in which several energy systems (renewable energy systems: photovoltaic panels, solar thermal collectors, heat pumps; fossil fuel energy systems: combined heat and power systems, gas boilers, absorption and compression chillers; thermal storage systems) interact in order to identify the best combination and management strategy in terms of fossil cumulative energy consumption and costs.

The concurrent optimization of both design and operation is identified by employing two algorithms, i.e., surrogate modeling optimization algorithm and mixed-linear-programming algorithm. Fossil cumulative energy demand (FCED) or total cost (TC) are separately set as the minimization target, by taking into account the variability of natural gas cost, CO2 emission cost, and electricity prices. Four different economic scenarios, which also consider future trends of costs and energy prices, are analyzed. In addition, a clustering procedure is employed to partition the data of energy demand into clusters in such a manner that their representative objects simulate the entire dataset and the computational time is significantly reduced. The Campus of the University of Parma (Italy) is selected as the case study to validate the methodology.

The proposed approach is demonstrated to be a powerful tool, since it identifies the optimal design and operation of the considered HEP in different economic scenarios. In fact, it allows to save up to 53% of FCED and up to 41% of TC. In addition, the leading technologies towards the 2030 scenario are identified, i.e., combined heat and power plant systems, heat pumps and absorption chillers.
Influence of External Heat Transfer on the Thermo-Structural Stress of a Radial Turbine Wheel
Authors: Balduzzi Francesco , Hoffer Pierre-Alain , Mosciaro Luigi , Mattiello Daniele , Rabbolini Silvio , Pini Nicola , Bianchini Alessandro , Ferrara Giovanni
Published: August 2024

Structural simulations are key for designing the wheel of a turbocharger’s turbine. These simulations enable the assessment of components’ durability and performance in demanding conditions such as extreme exhaust gas temperatures, facilitate the development of the cooling strategies that essential for managing excessive heat, and allow enhancing turbocharger efficiency and preventing catastrophic failures in high-temperature environments. External heat transfer plays a crucial role, since the housing temperature can reach values in the order of 103 K and the contribution of convective heat to ambient air is one of the major sources of loss.

The present paper aims to assess the influence of natural or forced convection between the turbine’s housing and the external ambient on the temperature and stress distributions of the turbine’s wheel. The methodology adopted for the analysis is based on a two-step approach. First, a three-dimensional steady-state conjugate heat transfer (CHT) simulation of the entire turbine stage (including volute, outlet duct, and wastegate valve) is performed to evaluate the temperature field on the metal body of the turbine. Then, the temperature distribution of the body is imported as a load for the thermo-structural simulation of the rotor wheel. The numerical setup was validated against experimental measurements of the temperature of the rotor blade. For the evaluation of the structural behavior of the component, the most critical regions in terms of stresses were identified in the backdisc part of the wheel. The results show the variation of the structural response as the external convection is increased from an ideal adiabatic condition to a forced external cooling condition. The impact of the same on the overall performance limits of the turbine are discussed.
Effects of Curvature and Compound Angle on Cooling Performance and Flow Characteristics for a Combustor Liner With Tangential Effusion Cooling Configuration
Authors: Chen Xuanwu , Zeng Qinghua , Li Ziwan , Xie Pengfu , Yao Min
Published: August 2024

Tangential effusion cooling is considered as an efficient and advanced scheme for combustor liner cooling. Extensive research on tangential effusion cooling has been focused on the outer liner. However, the performance of tangential effusion cooling differs between the inner and outer liners due to their different wall curvatures. In this study, the tangential effusion cooling based on the outer liner and inner liner under the different blowing ratio and compound angle has been investigated numerically to evaluate the overall cooling effectiveness, flow characteristics and heat transfer coefficients. The result shows that the effusion cooling based on the outer liner exhibits superior cooling effectiveness, enhanced film coverage, and reduced heat transfer coefficients compared to that based on inner liner. The overall cooling effectiveness for effusion cooling based on outer liner is about 10% higher than that based on inner liner. The coolant jets attached the wall and flowing spiral forward in the outer liner based model, while the cooling film is detached from the wall and mixed with the mainstream in the inner liner based model. The increase of blowing ratio leads to a larger area-averaged heat transfer coefficient but improves convective heat transfer within effusion holes and enhances overall cooling effectiveness of the liner, particularly for outer combustor liner. The large compound angle has a negligible effect on the area-averaged overall cooling effectiveness but increases non-uniformity in overall cooling effectiveness distribution. This provides a reference and database for the cooling design for annular combustor liner with low cooling air consumption.
Investigation of SPS Tungsten-Lithium Heat Pipe for Primary Heat Exchanger Applications
Authors: M. Prasad Abhilash , Torres Elena , Raju Nandhini , Otto Marcel , Vesely Ladislav , Fernandez Erik , Koyn Zachariah , Kapat Jayanta
Published: August 2024

The demand to reduce carbon emissions and establish sustainable sources of clean energy has increased the interest infusion reactors. Fusion reactors are devices that generate enormous amounts of energy. The result of the thermal energy needs to be transported to improve the reliability and safety of the reactor. One of the potential solutions is a heat pipe. Heat pipes are devices that can efficiently transport heat as well as cool the core of the reactor. Also, it helps for power generation by integrating it with power cycles. In this research, an alkali metal heat pipe, and a Super-critical Carbon Dioxide (sCO2) heat exchanger for a closed Brayton cycle is proposed. It starts from the selection of material and alkali metal for higher temperature application is chosen as tungsten and lithium. Spark Plasma Sintering is used to manufacture tungsten lithium heat pipe samples. The design of the heat pipe designated to transport 20–25 KW of energy. in an array configuration it is capable to transport 1–2 MW of energy. With this design analysis, the interface compactness emerges as a great advantage, allowing it to be used in fusion reactors, waste heat recovery for aircraft engines, gas turbines, and thermal management in hypersonic aircraft.
Control of Shroud Leakage Loss and Windage Torque in a Low-Pressure Turbine Stage
Authors: Christodoulou Loizos , Li Zhihui , Ambrose Stephen , Jefferson-Loveday Richard J. , Jackson Richard , Lock Gary , Sangan Carl , Scobie James
Published: August 2024

As new aeroengine architectures move to larger diameter fans and rotors, the associated increase in weight will need to be counterbalanced by lighter, more compact, and more efficient low-pressure turbines (LPT). Efficiency gains in LPTs can be achieved by reducing the losses associated with the shroud leakage flows. Flow control studies on the topic have traditionally focused on reducing the mixing loss, which constitutes a considerable proportion of the total loss. Nonetheless, increasing engine speeds are driving additional gains obtained by also targeting the reduction of windage losses. Developing a flow control solution with the dual objective of reducing over-tip cavity mixing and windage losses has not previously been attempted. This is a challenge due to conflicting flow control requirements and geometric constraints. Reducing windage loss generally requires increasing the swirl-ratio of the leakage flow, while reducing mixing loss requires reducing this ratio to match that of the main gas path. The current work proposes a novel flow control solution to successfully achieve this purpose through the emerging technology of additive manufacturing. The successful flow control concept was developed through numerical simulation, printed using an additive manufacturing process, and validated in a purpose-built rig. Experiments and computations were consistent with a cumulative reduction in cavity windage of 16%. The FCC is estimated to increase the mechanical efficiency of the turbine stage in isolation by 1%.