bluuebunny/crossref_metadata_2025 huggingface dataset:
The transfer effects of computational thinking: A systematic review with meta‐analysis and qualitative synthesis
Authors: Ye Jiachu , Lai Xiaoyan , Wong Gary Ka‐Wai
Published: September 2022

Background

Computational thinking (CT) is regarded as an essential 21st‐century skill, and attempts have been made to integrate it into other subjects. Instructional approaches to CT development and assessment in the field of computer science have attracted global attention, but the influence of CT skills on other subject areas is under‐researched.

Objective

Our goal is to investigate the transfer effects of CT in different subject areas and examine the educational characteristics of CT intervention approaches that promote the transfer of learning.

Method

We carefully selected and reviewed 55 empirical studies from leading bibliographic databases and examined the transfer of CT using a meta‐analysis and a qualitative synthesis.

Results and Conclusions

We identified and summarized these effects in the fields of mathematics, science, engineering and the humanities. A meta‐analysis of these studies identified a generally significant effect of the transfer of CT skills to other subject areas. We also explored the characteristics of CT interventions that aid the transfer of learning by qualitatively assessing the identified studies. The results of the review offer a holistic view of the trends in CT transfer research that can be used as a reference for both researchers and instructors.
Impaired repair properties of endothelial colony‐forming cells in patients with granulomatosis with polyangiitis
Authors: Del Rio Ana Paula Toledo , Frade‐Guanaes Jéssica O , Ospina‐Prieto Stephanie , Duarte Bruno K L , Bertolo Manoel Barros , Ozelo Margareth C , Sachetto Zoraida
Published: September 2022

In patients with ANCA‐associated vasculitis, interactions between neutrophils and endothelial cells cause endothelial damage and imbalance. Endothelial colony‐forming cells (ECFCs) represent a cellular population of the endothelial lineage with proliferative capacity and vasoreparative properties. This study aimed to evaluate the angiogenic capacity of ECFCs of patients with granulomatosis with polyangiitis (GPA). The ECFCs of 13 patients with PR3‐positive GPA and 14 healthy controls were isolated and characterized using fluorescence‐activated cell sorting, capillary tube formation measurement, scratching assays and migration assays with and without plasma stimulation. Furthermore, three patients with active disease underwent post‐treatment recollection of ECFCs for longitudinal evaluation. The ECFCs from the patients and controls showed similar capillary structure formation. However, the ECFCs from the patients with inactive GPA exhibited early losses of angiogenic capacity. Impairments in the migration capacities of the ECFCs were also observed in patients with GPA and controls (12th h, p = 0.05). Incubation of ECFCs from patients with GPA in remission with plasma from healthy controls significantly decreased migration capacity (p = 0.0001). Longitudinal analysis revealed that treatment significantly lowered ECFC migration rates. This study revealed that ECFCs from the patients with PR3‐positive GPA in remission demonstrated early losses of tube formation and reduced migration capacity compared to those of the healthy controls, suggesting impairment of endothelial function.
Effect of chitosan‐based melatonin composite coating on the quality of minimally processed pomegranate aril‐sacs during cold storage
Authors: Mwelase Sbulelo , Opara Umezuruike L. , Fawole Olaniyi A.
Published: September 2022

The current study evaluated the potential of chitosan‐based melatonin (CH‐MT) composite coating to maintain quality and delay senescence of minimally processed pomegranate aril‐sacs during refrigerated storage. Mature pomegranate fruit (cv. Wonderful) without physical defects were processed into aril‐sacs. Subsequently, the following treatments were applied; distilled water (control), CH 0.5% (w/v), CH+0.1 mM MT, CH+0.4 mM MT, CH+0.8 mM MT, and CH+1 mM MT. Each treatment was applied by immersing the aril‐sacs in the coating solution for 3 min and allowed to dry at room temperature. Aril‐sacs were then packed in polyethene terephthalate punnets (three to four aril‐sacs/punnet) and stored at 5°C and 85% RH for 21 days. Aril color, weight loss, respiration rate, ascorbic acid content, total anthocyanins, browning index, and antioxidant capacity were monitored during storage at 3 days intervals. The study results showed that the CH‐MT coating treatments significantly (p < 0.05) delayed the increase in aril‐sacs weight loss and respiration rate. These treatments also retained higher aril chroma, ascorbic acid, anthocyanin content, DPPH‐radical scavenging activity, and aril‐sacs antioxidant power (FRAP). In addition, surface browning development was significantly suppressed in the coated aril‐sacs compared with control sacs. However, the effectiveness of CH‐MT treatments in maintaining the quality of aril‐sacs was concentration‐dependent, with CH+0.8–1 mM MT treatments showing the best results. Therefore, CH+0.8–1 mM MT treatments are recommended to suppress the development of physiological disorders and maintain the quality of minimally processed pomegranate aril‐sacs.

Novelty Impact Statement

This study focuses on the development and application of chitosan‐melatonin composite coating (CH‐MT) as an active and functional formulation to maintain quality and extend the storage life of minimally processed pomegranate aril‐sacs. The results showed that incorporating melatonin with chitosan improved the effectiveness of chitosan base coating. This was demonstrated by the CH‐MT coating's enhanced retention of ascorbic acid, anthocyanins, radical scavenging activity, and antioxidant power. Further, delaying the increase in aril‐sacs surface browning, weight loss, and respiration rate. The study findings are valuable in the commercial adoption of safe preservation technologies to maintain the quality and maximize the storability of minimally processed products.
Association between early and current gastro‐intestinal symptoms and co‐morbidities in children and adolescents with Angelman syndrome
Authors: Leader G. , Whelan S. , Chonaill N. N. , Coyne R. , Tones M. , Heussler H. , Bellgard M. , Mannion A.
Published: September 2022

Background

Angelman syndrome (AS) is a neurogenetic disorder that causes severe intellectual disability, expressive language deficits, motor impairment, ataxia, sleep problems, epileptic seizures and a happy disposition. People with AS frequently experience gastrointestinal (GI) symptoms.

Method

This study used data from the Global Angelman Syndrome Registry to explore the relationship between early and current GI symptoms and co‐morbidity in children and adolescents with AS (n = 173). Two groups that experienced a high (n = 91) and a low (n = 82) frequency of GI symptoms were examined in relation to feeding and GI history in infancy, sleep and toileting problems, levels of language and communication and challenging behaviours. Predictors of GI symptoms were then investigated using a series of logistic regressions.

Results

This analysis found that constipation and gastroesophageal reflux affected 84% and 64%, of the sample, respectively. The high frequency of GI symptoms were significantly associated with: ‘refusal to nurse’, ‘vomiting’, ‘arching’, ‘difficulty gaining weight’, gastroesophageal reflux, ‘solid food transition’, frequency of night‐time urinary continence and sleep hyperhidrosis during infancy. GI symptoms were not significantly associated with sleep, toileting, language or challenging behaviours. Significant predictors of high frequency GI symptoms were gastroesophageal reflux and sleep hyperhidrosis.

Conclusions

Future research needs to investigate the association between AS and GI co‐morbidity in adults with AS.
Nevertheless, They Persisted: How Patterns of Opposition and Support Shaped the Survival of U.S. Abortion Clinics
Authors: Piazza Alessandro , Augustine Grace L.
Published: September 2022

Stigmatized organizations are generally assumed to face a variety of unique operational challenges. This paper examines the survival of stigmatized organizations in light of such challenges. Specifically, we investigate how patterns of opposition and support from multiple external stakeholders and audiences affect organizational survival within the context of abortion provision in the United States. We use a fuzzy‐set qualitative comparative analysis (fsQCA) to examine the causal linkages between the above factors and the survival outcomes of the full identifiable industry of 983 abortion clinics that were in operation in the U.S. between 2011 and 2017. Our results reveal the existence of multiple paths to survival, based primarily on either the absence of overt opposition or the presence of factors like political support that enabled organizations to overcome other threats to survival. Our findings show how socio‐political factors affect the survival of organizations in stigmatized industries.
Bullshit as a practical strategy for self‐deceptive narrators
Authors: Howe Leslie A.
Published: September 2022

This paper argues that bullshit is a practical resource for self‐deceiving individuals, or those who merely prefer to avoid self‐examination, insofar as it is able to provide a mask for poor doxastic hygiene. While self‐deception and bullshit are distinct phenomena, and bullshit does not cause self‐deception, bullshit disrupts the capacity to interrogate the motivational biasses that fuel deception. The communicative misdirection engaged in by ordinary social bullshitters is applied reflexively by the self‐deceiver to distort, evade, and obfuscate the self‐deceiver's self‐accounting. This discussion presupposes a broadly narrative approach to self‐awareness and discusses how a motivated susceptibility to bullshit offers an explanation how our reports about ourselves can be frequently at odds with reality, and suggests that a complacency about rational validation of belief outside of self‐certainty, i.e., the prevalence of bullshit, is even more of a threat than Frankfurt thought it to be.
Sally Lucas Jean, R.N. (1878–1971): Her historical legacy and lessons for contemporary public health nursing education
Authors: Carr Bryn , Scofield Elizabeth , Owens Janine , Donnelly Gloria , Aboul‐Enein Basil H.
Published: September 2022

Sally Lucas Jean, RN (1878–1971) pioneered health education in the United States and globally. At the time of her death in 1971, aged 93, her legacy included serving on boards of leading American health associations, spearheading public health projects worldwide and transforming thinking on contemporary public health education. Sally Lucas Jean's influence continues today, from her input on educational children's television programs, policies on child health and her involvement in developing the early foundations of health communication. In this historical reflection, we examine her role in defining health education and communication, alongside influencing and applying strategies to improve public health nursing.
Efficacy of ultraviolet A1 phototherapy for inflammatory, sclerotic and neoplastic dermatological diseases: A 10‐year tertiary referral center experience
Authors: Ronen Shachar , Ramot Yuval , Zlotogorski Abraham , Shreberk‐Hassidim Rony
Published: September 2022

Background

Ultraviolet (UV) A1 phototherapy is considered a beneficial treatment for various inflammatory, sclerotic, malignant, and other skin conditions. However, the available data regarding its efficacy for different indications, the potential side effects, and the recommended treatment protocols are sparse.

Objectives

To assess the efficacy of UVA1 phototherapy and identify correlation between different indications and treatment protocols to response rates.

Methods

We performed a retrospective study of a cohort of 335 patients treated with UVA1 phototherapy at the Department of Dermatology at Hadassah Medical Center, Jerusalem, Israel, between 2008 and 2018.

Results

The study population included 163 patients with inflammatory diseases (mainly atopic dermatitis and other types of eczema), 67 patients with sclerotic diseases (morphea and graft versus host disease), nine patients with neoplastic diseases (cutaneous T cell lymphoma), and 188 patients with other cutaneous disorders. Response rates ranged between 85% and 89% across indications, without differences in response rates among the indication groups (p = .941). In a multivariant logistic regression model, increased number of treatments and higher maximal dosages were associated with response to treatment (p < .001). Using ROC analysis, a cut‐off of 8 UVA1 phototherapy treatments was chosen as predictive for beneficial response (86.4% sensitivity, 78% specificity). A cut‐off of 40 J/cm2 was chosen as an optimal maximal dosage for differentiating between responders and non‐responders (51.1% sensitivity, 83.1% specificity).

Conclusions

UVA1 phototherapy is an effective treatment for a variety of skin conditions. In most patients, at least eight treatments of a medium‐high dosage are required for clinical response.
Transcriptomic and methylation analysis of susceptible and tolerant grapevine genotypes following Plasmopara viticola infection
Authors: Azevedo Vanessa , Daddiego Loretta , Cardone Maria Francesca , Perrella Giorgio , Sousa Lisete , Santos Rita B. , Malhó Rui , Bergamini Carlo , Marsico Antonio Domenico , Figueiredo Andreia , Alagna Fiammetta
Published: September 2022

Downy mildew, caused by the biotrophic oomycete Plasmopara viticola, is one of the most economically significant grapevine diseases worldwide. Current strategies to cope with this threat rely on the massive use of chemical compounds during each cultivation season. The economic costs and negative environmental impact associated with these applications increased the urge to search for sustainable strategies of disease control. Improved knowledge of plant mechanisms to counteract pathogen infection may allow the development of alternative strategies for plant protection. Epigenetic regulation, in particular DNA methylation, is emerging as a key factor in the context of plant–pathogen interactions associated with the expression modulation of defence genes. To improve our understanding of the genetic and epigenetic mechanisms underpinning grapevine response to P. viticola, we studied the modulation of both 5‐mC methylation and gene expression at 6 and 24 h post‐infection (hpi). Leaves of two table grape genotypes (Vitis vinifera), selected by breeding activities for their contrasting level of susceptibility to the pathogen, were analysed. Following pathogen infection, we found variations in the 5‐mC methylation level and the gene expression profile. The results indicate a genotype‐specific response to pathogen infection. The tolerant genotype (N23/018) at 6 hpi exhibits a lower methylation level compared to the susceptible one (N20/020), and it shows an early modulation (at 6 hpi) of defence and epigenetic‐related genes during P. viticola infection. These data suggest that the timing of response is an important mechanism to efficiently counteract the pathogen attack.
Dignity in nursing: A bibliometric and visual analysis of scientific publications
Authors: Liu Yu‐Jia , Li Xue‐Ying , Wang Yan‐Jie , Li Xiao‐Han
Published: September 2022

Background

Dignity‐conserved nursing has been widely studied by scholars all over the world; however, there is no clear direction in which this field is trending.

Aim

To conduct a bibliometric analysis that systematically characterises publications on dignity research in the nursing field from 2011 to 2020.

Design

Bibliometric and visual analysis of retrieved articles.

Methods

The Web of Science Core Collection database was used to retrieve all articles which addressed dignity in nursing from 2011 to 2020. The WoSCC's own analysis tool, CiteSpace and VOSviewer, were used to obtain visual analysis results. Reporting follows the STROBE checklist.

Results

A total of 1429 papers on dignity care are included in this study. We found that the number of papers on this topic increased steadily, and the United States topped the list with 366 articles in total. The institute with the most publications was King's College London, and the most widely published journal was Nursing Ethics. We were able to identify four major research topics, namely dignity in: (a) palliative care, (b) dementia and the elderly, (c) health care and (d) nursing ethics. Terminally ill patient, home, value, rehabilitation and psychological distress were the five keywords with the highest burst strength.

Conclusions

The interest in dignity care research has been steadily increasing from 2011 and is reflected in the number of published papers. The United States and Western Europe are leading in this field, both having a high number of cutting‐edge researchers and high‐level scientific research institutions. In the domain of dignity care, several stable and high‐yield core author groups have been formed. While the existing research mainly focuses on four hot spots, psychological distress, advanced cancer, maternity care and content analysis may be the research frontiers.
A conserved HSF:miR169:NF‐YA loop involved in tomato and Arabidopsis heat stress tolerance
Authors: Rao Sombir , Gupta Apoorva , Bansal Chandni , Sorin Celine , Crespi Martin , Mathur Saloni
Published: September 2022

Heat stress transcription factors (HSFs) and microRNAs (miRNAs) regulate different stress and developmental networks in plants. Regulatory feedback mechanisms are at the basis of these networks. Here, we report that plants improve their heat stress tolerance through HSF‐mediated transcriptional regulation of MIR169 and post‐transcriptional regulation of Nuclear Factor‐YA (NF‐YA) transcription factors. We show that HSFs recognize tomato (Solanum lycopersicum) and Arabidopsis MIR169 promoters using yeast one‐hybrid/chromatin immunoprecipitation–quantitative PCR. Silencing tomato HSFs using virus‐induced gene silencing (VIGS) reduced Sly‐MIR169 levels and enhanced Sly‐NF‐YA9/A10 target expression. Further, Sly‐NF‐YA9/A10 VIGS knockdown tomato plants and Arabidopsis plants overexpressing At‐MIR169d or At‐nf‐ya2 mutants showed a link with increased heat tolerance. In contrast, Arabidopsis plants overexpressing At‐NF‐YA2 and those expressing a non‐cleavable At‐NF‐YA2 form (miR169d‐resistant At‐NF‐YA2) as well as plants in which At‐miR169d regulation is inhibited (miR169d mimic plants) were more sensitive to heat stress, highlighting NF‐YA as a negative regulator of heat tolerance. Furthermore, post‐transcriptional cleavage of NF‐YA by elevated miR169 levels resulted in alleviation of the repression of the heat stress effector HSFA7 in tomato and Arabidopsis, revealing a retroactive control of HSFs by the miR169:NF‐YA node. Hence, a regulatory feedback loop involving HSFs, miR169s and NF‐YAs plays a critical role in the regulation of the heat stress response in tomato and Arabidopsis plants.
Host‐associated variability of the cdtABC operon, coding for the cytolethal distending toxin, in Campylobacter jejuni
Authors: Guirado Pedro , Iglesias‐Torrens Yaidelis , Miró Elisenda , Navarro Ferran , Attolini Camile Stephan‐Otto , Balsalobre Carlos , Madrid Cristina
Published: September 2022

Campylobacter, a major cause of food‐borne gastroenteritis worldwide, colonize the gastrointestinal tract of a wide range of animals, being birds the main reservoir. The mechanisms involved in the interaction of Campylobacter with the different hosts are poorly understood. The cytolethal distending toxin, encoded in the cdtABC operon, is considered a pivotal virulence factor during human infection. Differences in the prevalence of cdtABC genes in Campylobacter isolates from three distinct origins (wild birds, broiler chickens and humans) prompted us to further characterize their allelic variability. The sequence of cdtABC is highly conserved among broiler and human isolates. A high diversity of cdtABC alleles was found among wild bird isolates, including several alleles that do not produce any functional CDT. These results suggest that specific variants of the cdtABC operon might define the host range of specific Campylobacter jejuni isolates. Moreover, our data indicate that PCR methodology is inaccurate to characterize the prevalence of the cdt genes, since negative PCR detection can be the result of divergences in the sequence used for primer design rather than indicating the absence of a specific gene.
Changes in vastus lateralis fibre cross‐sectional area, pennation angle and fascicle length do not predict changes in muscle cross‐sectional area
Authors: Ruple Bradley A. , Mesquita Paulo. H. C. , Godwin Joshua S. , Sexton Casey L. , Osburn Shelby C. , McIntosh Mason C. , Kavazis Andreas N. , Libardi Cleiton A. , Young Kaelin C. , Roberts Michael D.
Published: September 2022

New Findings

What is the central question of this study?

Do changes in myofibre cross‐sectional area, pennation angle and fascicle length predict vastus lateralis whole‐muscle cross‐sectional area changes following resistance training?

What is the main finding and its importance?

Changes in vastus lateralis mean myofibre cross‐sectional area, fascicle length and pennation angle following a period of resistance training did not collectively predict changes in whole‐muscle cross‐sectional area. Despite the limited sample size in this study, these data reiterate that it remains difficult to generalize the morphological adaptations that predominantly drive tissue‐level vastus lateralis muscle hypertrophy.

Myofibre hypertrophy during resistance training (RT) poorly associates with tissue‐level surrogates of hypertrophy. However, it is underappreciated that, in pennate muscle, changes in myofibre cross‐sectional area (fCSA), fascicle length (Lf) and pennation angle (PA) likely coordinate changes in whole‐muscle cross‐sectional area (mCSA). Therefore, we determined if changes in fCSA, PA and Lf predicted vastus lateralis (VL) mCSA changes following RT. Thirteen untrained college‐aged males (23 ± 4 years old, 25.4 ± 5.2 kg/m2) completed 7 weeks of full‐body RT (twice weekly). Right leg VL ultrasound images and biopsies were obtained prior to (PRE) and 72 h following (POST) the last training bout. Regression was used to assess if training‐induced changes in mean fCSA, PA and Lf predicted VL mCSA changes. Correlations were also performed between PRE‐to‐POST changes in obtained variables. Mean fCSA (+18%), PA (+8%) and mCSA (+22%) increased following RT (P < 0.05), but not Lf (0.1%, P = 0.772). Changes in fCSA, Lf and PA did not collectively predict changes in mCSA (R2= 0.282, adjusted R2 = 0.013, F3,8 = 1.050, P = 0.422). Moderate negative correlations existed for percentage changes in PA and Lf (r = −0.548, P = 0.052) and changes in fCSA and Lf (r = −0.649, P = 0.022), and all other associations were weak (|r| < 0.500). Although increases in mean fCSA, PA and VL mCSA were observed, inter‐individual responses for each variable and limitations for each technique make it difficult to generalize the morphological adaptations that predominantly drive tissue‐level VL muscle hypertrophy. However, the small subject pool is a significant limitation, and more research in this area is needed.
Optimized J Evaluation Scheme for the Fracture Mechanics Assessment of Complex Piping Systems Subjected to Various Loading Sets
Authors: Chapuliot Stephane , Marie Stephane
Published: September 2022

This paper describes an optimization scheme for the J parameter calculation of cracks postulated in complex geometrical configurations such as elbow entries/exits and/or thickness transitions. The principle of this scheme comes from the RSE-M/5.4 Appendix allowing the definition of a specific compendium for given configurations. After a detailed presentation of the numerical protocol, an illustration of the required effort and the potential benefits is proposed for an elbow configuration. It is then shown that: The effort is significant but can be anticipated and automated and The potential benefit in terms of applied J is significant (a ratio of three in the proposed application).
Study on Effects of Spanwise-Expansion Parameters on Film Cooling Effectiveness of Diffusion Shaped Hole Configurations
Authors: Liu Cun-Liang , Li Bing-Ran , Song Hui , Chen Lei , Wang Rui , Wang Yong-Ming , Liang Da-Peng
Published: September 2022

Diffusion shaped holes are widely used on aero-engine turbine blades for film cooling. The effect of the spanwise-expansion angle and spanwise width of the hole exit on the film cooling effectiveness of diffusion shaped holes was investigated in this study. The film cooling effectiveness was obtained through the pressure-sensitive paint (PSP) technique on a plate model at five momentum ratios (0.11, 0.43, 0.97, 1.73, and 2.71). A numerical simulation was performed to analyze the flow mechanism. The laid-back fan-shaped (LBFS) holes and the fan-shaped holes with three spanwise-expansion angles (FS-A: 7 deg, 11 deg, and 15 deg) and with three spanwise widths of the hole exits (FS-B: 1.7d, 2.3d, and 3.4d) were used for the study. The results revealed that the film cooling effectiveness of fan-shaped holes (FS-A) increases monotonically as the spanwise-expansion angle increases, while the film cooling effectiveness of the LBFS holes increases first and then decreases as the spanwise-expansion angle increases. However, the film cooling effectiveness of the two kinds of holes (LBFS and FS-B) both increase first and then decrease with the increase of the spanwise width of hole exit. The mainstream intrusion occurred at the same spanwise width of the hole exit of 3.4d for both kinds of holes. The laid-back fan-shaped hole possessed high resistance to cooling performance decline. The importance of the spanwise width of the hole exit as a key parameter was emphasized in this study.
Magnetic Resonance Velocimetry of a Turbine Blade With Engine-Representative Internal and Film Cooling Structures
Authors: Ma Haiteng , Liu Yisu , Lai Youkui , Ouyang Hua , Ning Jia , Jiang Xianwang , Xu Qin
Published: September 2022

As a key technology to ensure turbine survival, blade cooling encompasses a whole range of strategies with ever-increasing geometric complexities. Flow measurement for turbine blades with such intricate internal and external cooling structures is very challenging and calls for non-intrusive, three-dimensional measuring techniques. As a response, this work utilizes magnetic resonance velocimetry (MRV) to measure the velocity field in a scaled turbine blade with engine-representative internal and film cooling structures. Internal cooling structures include leading edge impingement cooling, U-shaped serpentine passage with/without turbulence ribs at blade mid-chord, and trailing edge pin fins. External cooling structures include film holes near the leading edge stagnation point, at the blade tip, and on the trailing edge. Experiments were performed in water and the Reynolds number local to the leading edge, mid-chord, and trailing edge cooling channels falls within the range typically reported in the literature. This is the first time that MRV is used to measure the flow field of a turbine blade with all the typical internal and external cooling geometries combined. The results show that MRV has great capacity in measuring the complex fluid flow associated with blade cooling designs. Vortical flow features in leading edge impingement cooling, and at the U-bends of mid-chord serpentine channel are captured. Interestingly, internal flow around pin fins redistributes the velocity of external flow ejected from trailing edge slots and film holes, indicating strong coupling between the internal and film cooling flow of the turbine blade.
A Fluid–Structure Interaction Tool Using a Van der Pol-Based Reduced-Order Model for Buffet and Nonsynchronous Vibrations
Authors: Hollenbach Richard , Kielb Robert , Hall Kenneth
Published: September 2022

This paper builds upon a two-degree-of-freedom Van der Pol oscillator-based reduced-order model for studying the mechanisms around nonsynchronous vibrations (NSV) in turbomachinery. One degree tracks the fluid motion utilizing a combination of a traditional Van der Pol oscillator and a Duffing oscillator; the other degree of freedom is a mass on a spring and a damper, in this case, a cylinder. Thus, this model can be considered one of fluid–structure interaction. The cubic stiffening from the Duffing oscillator proved to improve the match to experimental data. Using this model to study the time history of the fluid and the structure oscillation, additional parameters are extracted to understand the underlying mechanisms of frequency lock-in and limit cycle oscillation. First, the phase shift between the vortex shedding and the structural motion is calculated when it locks-in and then unlocks. Second, the work done per cycle is analyzed from the contributions of the mass, spring, and damping forces to determine the dominant contributor when locking-in versus unlocking. Third, the phase portrait is plotted on a Poincaré map to further study the locked-in versus unlocked responses. This model is then validated against not only experimental data but also computational simulation results and previous reduced-order models. The finalized model can now serve as a preliminary design tool for turbomachinery applications. For more realistic and accurate modeling, the third degree of freedom in the form of an airfoil pitching motion will be added in a separate paper as well.
Azimuthal Instabilities of an Annular Combustor With Different Swirling Injectors
Authors: Rajendram Soundararajan Preethi , Durox Daniel , Renaud Antoine , Candel Sébastien
Published: September 2022

Experiments are carried out on the laboratory-scale MICCA-Spray annular combustor to examine the effects of swirlers on combustion instabilities. This system comprises 16 spray-swirl injectors and gives rise to instabilities coupled by azimuthal modes. Five types of swirlers producing clockwise rotation and varying in swirl numbers and pressure drops are considered. These swirlers can be broadly categorized into two groups: lower-swirl and higher-swirl groups, based on their swirl numbers. An arrangement where clockwise and counterclockwise swirlers alternate is also studied. Experiments are performed systematically with liquid heptane at five levels of thermal power and six equivalence ratios. Results reveal that none of the swirlers in the lower-swirl category exhibit instability in the operating region considered, whereas the higher-swirl units feature strong azimuthal instabilities that trace an overall limit cycle envelope with a few short and random bursts. Among the higher-swirl group, a higher pressure drop swirler is associated with a broader instability map. This shows that the transition to instability mainly depends on the swirl number through its effect on the flame structure and that the pressure drop adds to further variations in amplitude and frequency of oscillation. The spin ratio time series indicate that the modes are of mixed type and that their distribution depends on the operating condition. On specifically comparing the spin ratio distribution between a full set of clockwise rotating (CR) swirlers and a configuration where clockwise and counterclockwise rotating swirlers (CCR) are alternatively placed, it is found that there is no definite statistical preference for spin ratio linked to the effect of bulk swirl. In some cases, however, the CCR configuration promotes a broader distribution of spin ratios centered around the standing mode (sr = 0) while the CR setup favors azimuthal modes spinning in the counterclockwise direction. An attempt is made to interpret the occurrence of instabilities by making use of flame describing functions (FDFs) measured in a single-injector combustor. It is found that the FDFs corresponding to the two swirler categories (lower-swirl and higher-swirl) are relatively distinct. The observed behavior is tentatively interpreted using an instability analysis in which the injector and upstream plenum are represented by an impedance that shifts the band of instability. The unstable behavior is then linked to the relative position of the FDF phase with respect to the instability band in the frequency range corresponding to the expected azimuthal mode frequency. The phase and gain of the FDF notably depend on the swirl number, and it is possible to distinguish, for the present configuration, a category of low swirl number injectors inducing stable operation and another category of high swirl number units leading to oscillations.
Analysis of a Multi-Generation Renewable Energy System With Hydrogen-Fueled Gas Turbine
Authors: Bahlawan Hilal , Losi Enzo , Manservigi Lucrezia , Morini Mirko , Spina Pier Ruggero , Venturini Mauro
Published: September 2022

Solar energy is considered one of the most affordable renewable resources for meeting current energy demands and mitigating environmental problems. However, the exploitation of solar energy is challenging because of both diurnal and seasonal variations. Power-to-hydrogen technologies can play a key role to counterbalance the variation of solar irradiance. Moreover, hydrogen-fueled gas turbines are considered promising technologies to decarbonize the electricity sector. To tackle these concerns, this paper presents a multigeneration energy system operated in island mode in which a hydrogen-fueled gas turbine is coupled with a solar photovoltaic plant, an electrolyzer, an absorption chiller, electric and thermal energy storage, as well as a hydrogen storage. Therefore, the energy system is 100% based on renewable energy. The sizes of the components are optimized by maximizing the exploitation of renewable energy sources, while the supply of electricity from the national grid must be null. Moreover, the effect of ambient conditions on the optimal sizing is also investigated by considering the thermal, cooling, and electrical energy demands of two case studies located in two different climatic zones. The paper demonstrates that the adoption of hydrogen-fueled gas turbines coupled with power-to-hydrogen technologies can effectively support the transition toward a clean energy supply. Moreover, this study provides a procedure for the optimal sizing of a multigeneration energy system fully based on solar energy, by also demonstrating that both photovoltaic (PV) panel area and hydrogen storage volume are feasible, if compared to the considered district layout.
A New Interpretation of Hot Gas Ingress Through Turbine Rim Seals Influenced by Mainstream Annulus Swirl
Authors: Graikos Dimitrios , Tang Hui , Sangan Carl M. , Lock Gary D. , Scobie James A.
Published: September 2022

Rim seals are fitted at the periphery of the stator and rotor disks to reduce the adverse effects of hot gas ingress on highly stressed turbine components limited by temperature. Ingress is induced by rotational effects such as disk pumping, as well as by asymmetric pressure-driven unsteady phenomena. These influences superpose to form a complex flow-physics problem that is a challenge for computational fluid dynamics. Engine designers typically use practical low-order models that require empirical validation and correlating parameters. This paper identifies the swirl ratio in the mainstream annulus as a dominant characterizing parameter to predict ingress. This is a new interpretation that is supported by extending a low-order model based on turbulent transport using an effective eddy mixing length based on the difference in swirl between the annulus and seal clearance. Experimental measurements were made using a 1.5-stage turbine rig at low Reynolds number. The influence of annulus swirl ratio was investigated over a range of flow conditions and two rim-seal geometries, with the ingress quantified using CO2 tracer concentration in the sealing flow. The concentration data were complemented by measurements in the annulus using a five-hole aerodynamic probe.
Aging Effect–Aware Finite Element Model and Parameter Identification Method of Lithium-Ion Battery
Authors: Tian Aina , Yang Chen , Gao Yang , Jiang Yan , Chang Chun , Wang Lujun , Jiang Jiuchun
Published: September 2022

Battery aging is an inevitable macroscopic phenomenon in the use of the battery, which is characterized by capacity decline and power reduction. If the charging and discharging strategy does not adjust with the aging state, it is easy to cause battery abuse and accelerate the decline. To avoid this situation, the aging model with consideration of the battery degradation is coupled into the pseudo-two-dimensional (P2D) model. An aging effect-aware finite element model that can describe battery physical information accurately is presented in this article. The model parameters are divided into four parts: structure parameters, thermodynamic parameters, kinetic parameters, and aging parameters. The identification experiments are designed based on the characteristics of these types of parameters. The decoupling and parameter identification methods of kinetic parameters according to the response characteristics of each parameter under specific excitation, and state-of-charge (SOC) partitioned range identification technology of aging parameters is proposed and verified. Finally, the aging effect-aware model and the identification parameters are verified under constant current (CC) and different dynamic conditions with different charge rate (C-rate). The ability of the proposed model to track the aging trajectory in the whole life cycle is verified under various cycle conditions. The proposed model can be applied to aging mechanism analysis and health management from point of inner properties of the batteries.
Numerical Study of Large Footprint (24 × 24 mm2) Silicon-Based Embedded Microchannel Three-Dimensional Manifold Coolers
Authors: Wei Tiwei , Hazra Sougata , Lin Yujui , Gupta Man Prakash , Degner Michael , Asheghi Mehdi , Goodson Kenneth E.
Published: September 2022

Silicon-based embedded microchannel with three-dimensional (3D) manifold (MF) μ-cooler offers lower pressure drop and increased heat removal capability (>1 kW/cm2) for microprocessors and power electronics cooling using single-phase water. In this paper, we present a thermal–fluidic numerical analysis of silicon-embedded microchannel cooling. We develop a full-scale computational fluid dynamics (CFD) model of a large footprint (24 × 24 mm2) device having embedded microchannels and a 3D manifold. It is found that the pressure/velocity distributions at three different critical regions inside the inlet manifold have a significant impact on the temperature distribution. A previous study reported a shift of the chip temperature hot-spot at high flow rates; this study delves deep into the flow and pressure variations within the MF and cold plate (CP) that leads to this shift. This study also investigates the degree of flow maldistribution, first between the manifold channels caused by the plenum and then between the cold plate channels caused by individual MF channels. Finally, this study concludes with a comparison between two different 3D manifold inlet channel heights. The comparison reveals that the manifold with 1.5 mm thickness can reduce the pressure drop by a factor of 4 while maintaining the same thermal resistance of 0.04 K cm2/W, thus indicating an increase in the coefficient of performance (COP) by a factor of 4, compared with a manifold thickness of 0.7 mm.
Predictions of the Elastic–Plastic Compressive Response of Functionally Graded Polymeric Composite Lattices Manufactured by Three-Dimensional Printing
Authors: Plocher János , Tagarielli Vito L. , Panesar Ajit
Published: September 2022

We use three-dimensional printing to manufacture lattices with uniform and graded relative density, made from a composite parent material comprising a nylon matrix reinforced by short carbon fibers. The elastic–plastic compressive response of these solids is measured up to their densification regime. Data from experiments on the lattices with uniform relative density are used to deduce the dependence of their elastic–plastic homogenized constitutive response on their relative density, in the range 0.2–0.8. These data are used to calibrate finite element (FE) simulations of the compressive response of functionally graded lattices (FGLs), which are found in good agreement with the corresponding measurements, capturing the salient features of the measured stress versus strain responses. This exercise is repeated for two lattice topologies (body-centered cubic and Schwarz-P). The phenomenological constitutive models produced in this study can be used in topology optimization to maximize the performance of 3D-printed FGLs components in terms of stiffness, strength, or energy absorption.
Diffraction and Refraction of Nonlinear Waves by the Green–Naghdi Equations
Authors: Hayatdavoodi Masoud , Cengiz Ertekin R.
Published: September 2022

Diffraction and refraction of nonlinear shallow water waves due to uneven bathymetry are studied by use of the Green–Naghdi (GN) equations in three dimensions. A numerical wave tank consisting of deep, transitional, and shallow regions is created. Various forms of three-dimensional bathymetry, consisting of ramps with nonuniform profiles and large slopes, are used to connect the deep-water side of the tank to the shallow water shelf. A wavemaker is placed at the upwave side of the domain, capable of generating solitary and cnoidal waves of the GN equations. A numerical wave absorber is located downwave of the domain to minimize the wave reflection back into the domain. The system of equations is solved numerically in time domain by use of a second-order finite-difference approach for spatial discretization, and in a boundary-fitted coordinate system, and by use of the modified Euler method for time marching. Results include solitary and cnoidal wave surface elevation and particle velocities and are compared with the existing solutions where possible. Overall, very good agreement is observed. Discussion is provided on the nonlinearity and dispersion effects on the wave diffraction and refraction by the various forms of the ramps, as well as on the performance of the GN equations in solving these problems.
A Simplified Method to Analyze Dynamic Response of VLFS Based on the Kane Method
Authors: Liu Junyi , Chen Xujun , Huang Heng , Ji Song , Tu Qunzhang
Published: September 2022

A two-dimensional (2D) simplified model of the very large floating structure (VLFS) is formulated based on Huston's interpretation of the Kane methodology. In this proposed model, the VLFS is considered as a series of discrete floating bodies connected by elastic hinges. The rotation stiffness of elastic hinges has a great influence on the dynamic responses of VLFS and its value is determined based on the vertical displacements equivalent between the simply supported beam model and the elastically hinged multiple bodies model with the same boundary conditions on a concentrated load. Reduced Kane equations are used in the actual dynamic analysis, once initial conditions and mechanical analysis of the system have been formulated. Validation of the Kane-based method and the reliability of the corresponding program developed are established by several comparative studies on a continuous structure and a hinged structure with three parts. The predictions based on the proposed method are essentially identical to the model test data and calculation results provided by related literature.
The Microstructural Properties and Tribological Performance of Al2O3 and TiN Nanoparticles Reinforced Ti–6Al–4V Composite Coating Deposited on AISI304 Steel by TIG Cladding
Authors: Kumar Joijode Kiran , Rao Thella Babu , Krishna Konjeti Rama
Published: September 2022

This investigation presents the tribological performance of (Al2O3 + TiN)/Ti6Al4V cladding deposited on AISI304 steel substrate by the tungsten inert gas (TIG) cladding approach. The microstructural characterization by SEM confirmed claddings with visually crack-free and sound metallurgical bonding at the clad layer—substrate interface. The energy dispersive spectroscopy (EDS) analysis revealed the presence of matrix and reinforcement phases as major elements with the clad layer and with considerably no oxidation during their deposition. The XRD spectra revealed that matrix and reinforcements are dominant phases in the clad layer. The formation of compounds reflected considerably a lower dilution of reinforcement phase with Ti6Al4V matrix during melting and deposition. Higher the microhardness of the (Al2O3 + TiN)/Ti6Al4V clad layer in the cladding zone compared with other clad layer compositions such as Ti6Al4V, Al2O3/Ti6Al4V, and TiN/Ti6Al4V, it is varied from 1130HV0.2 to 1222HV0.2, and the average microhardness is about 990.57HV0.2 which is 175% improvement compared with the substrate. The cladding with dual reinforcement composition has shown a superior wear resistance compared with all other clad layer composite compositions. The improvement in the wear resistance achieved with (Al2O3 + TiN)/Ti6Al4V composite clad layer deposition at 2.5 m/s, 3.5 m/s, and 4.5 m/s sliding velocities is 56.60%, 63.26%, and 68.53%, respectively, compared with the substrate. The wear morphology of the composite claddings is relatively smoother and the wear furrows are shallower compared with the substrate, especially for the composite clad layer with (Al2O3 + TiN) reinforcement phase.
Reconsidering commonly used stimuli in speech perception experiments
Authors: Winn Matthew B. , Wright Richard A.
Published: September 2022

This paper examines some commonly used stimuli in speech perception experiments and raises questions about their use, or about the interpretations of previous results. The takeaway messages are: 1) the Hillenbrand vowels represent a particular dialect rather than a gold standard, and English vowels contain spectral dynamics that have been largely underappreciated, 2) the /ɑ/ context is very common but not clearly superior as a context for testing consonant perception, 3) /ɑ/ is particularly problematic when testing voice-onset-time perception because it introduces strong confounds in the formant transitions, 4) /dɑ/ is grossly overrepresented in neurophysiological studies and yet is insufficient as a generalized proxy for “speech perception,” and 5) digit tests and matrix sentences including the coordinate response measure are systematically insensitive to important patterns in speech perception. Each of these stimulus sets and concepts is described with careful attention to their unique value and also cases where they might be misunderstood or over-interpreted.