bluuebunny/crossref_metadata_2025 huggingface dataset:
Moving on up: Vertical distribution shifts in rocky reef fish species during climate‐driven decline in dissolved oxygen from 1995 to 2009
Authors: Meyer‐Gutbrod Erin , Kui Li , Miller Robert , Nishimoto Mary , Snook Linda , Love Milton
Published: September 2021

Anthropogenic climate change has resulted in warming temperatures and reduced oxygen concentrations in the global oceans. Much remains unknown on the impacts of reduced oxygen concentrations on the biology and distribution of marine fishes. In the Southern California Channel Islands, visual fish surveys were conducted frequently in a manned submersible at three rocky reefs between 1995 and 2009. This area is characterized by a steep bathymetric gradient, with the surveyed sites Anacapa Passage, Footprint and Piggy Bank corresponding to depths near 50, 150 and 300 m. Poisson models were developed for each fish species observed consistently in this network of rocky reefs to determine the impact of depth and year on fish peak distribution. The interaction of depth and year was significant in 23 fish types, with 19 of the modelled peak distributions shifting to a shallower depth over the surveyed time period. Across the 23 fish types, the peak distribution shoaled at an average rate of 8.7 m of vertical depth per decade. Many of the species included in the study, including California sheephead, copper rockfish and blue rockfish, are targeted by commercial and recreational fisheries. CalCOFI hydrographic samples are used to demonstrate significant declines in dissolved oxygen at stations near the survey sites which are forced by a combination of natural multidecadal oscillations and anthropogenic climate change. This study demonstrates in situ fish depth distribution shifts over a 15‐year period concurrent with oxygen decline. Climate‐driven distribution shifts in response to deoxygenation have important implications for fisheries management, including habitat reduction, habitat compression, novel trophic dynamics and reduced body condition. Continued efforts to predict the formation and severity of hypoxic zones and their impact on fisheries dynamics will be essential to guiding effective placement of protected areas and fisheries regulations.
High temperature mechanical behavior of low stiffness Al2TiO5 and Al2TiO5–3Al2O3.2SiO2–ZrTiO4 composite materials
Authors: Violini María Agustina , Hernández María Florencia , Gass Sebastian Emiliano , Tomba Martinez Analía Gladys , Rendtorff Nicolás Maximiliano
Published: September 2021

The mechanical behavior of low (and negative) thermal expansion and low stiffness Al2TiO5 materials and Al2TiO5–3Al2O3.2SiO2–ZrTiO4 composite materials was studied by diametral compression test at room temperature 400 and 800°C. The effect of both temperature and composition was analyzed. Stress–strain curves were obtained and, from them, apparent elastic modulus (Eapp) and mechanical strength (σF) were determined. Fracture mechanisms and fracture patterns were also analyzed. All materials showed a brittle behavior up to 800°C. The thermal variation of σF, that was even higher as testing temperature increased, was interpreted based on the microcracks behavior. A double linear correlation of Eapp was found with temperature (T) and zircon content ([Z]), with a fitting coefficient > .9. The particular low stiffness and the mechanical and thermal behavior of the studied materials suggest that they would be able to withstand thermal stresses.
Does the microbiota spectrum of prostate secretion affect the clinical status of patients with chronic bacterial prostatitis?
Authors: Kogan Mikhail , Naboka Yulia , Ferzauli Akhmed , Ibishev Khalid , Gudima Irina , Ismailov Ruslan
Published: September 2021

Objective

To explore the influence of the microbiota of prostate secretion on the clinical status of patients with chronic bacterial prostatitis.

Methods

This was an observational, single‐center, comparative study. We evaluated the survey cards of 230 outpatients aged 18–45 years with a history of prostatitis from 2012 to 2019. As a result, 170 outpatients were selected for the study. All patients underwent an assessment of symptoms using International Prostate Symptom Score‐quality of life, National Institutes of Health‐Chronic Prostatitis Symptom Index, International Index of Erectile Function, pain visual analog scale. A bacteriological study (after the Meares–Stamey test) of post‐massage urine was carried out on an extended media set. The following parameters were determined in each patient: leukocyturia and bacteriuria, serum testosterone and total prostate‐specific antigen levels. Uroflowmetry, transrectal prostate ultrasound with color duplex mapping and ejaculate analysis were also carried out.

Results

Aerobic–anaerobic bacterial associations were identified in all patients. Three comparison groups were identified depending on the microbiota’s spectrum (in post‐massage urine): aerobes prevailed in group 1 (n = 67), anaerobes prevailed in group 2 (n = 33), and the levels of aerobic and anaerobic bacteriuria were higher than ≥103 colony‐forming units per mL in group 3 (n = 70). It was found that the severity of clinical symptoms (urination disorders, sexual dysfunction etc.) of chronic bacterial prostatitis, laboratory and instrumental changes (testosterone, prostate‐specific antigen, prostate volume etc.) in groups 2 and 3 were significantly higher than in group 1.

Conclusion

In patients with chronic bacterial prostatitis, a predominance of anaerobes or a combination of aerobes and anaerobes in a titer of ≥103 colony‐forming units per mL in post‐massage urine is associated with worse clinical status.
Medical student knowledge and critical appraisal of machine learning: a multicentre international cross‐sectional study
Authors: Blacketer Charlotte , Parnis Roger , B. Franke Kyle , Wagner Morganne , Wang David , Tan Yiran , Oakden‐Rayner Luke , Gallagher Steve , Perry Seth W. , Licinio Julio , Symonds Ian , Thomas Josephine , Duggan Paul , Bacchi Stephen
Published: September 2021

To utilise effectively tools that employ machine learning (ML) in clinical practice medical students and doctors will require a degree of understanding of ML models. To evaluate current levels of understanding, a formative examination and survey was conducted across three centres in Australia, New Zealand and the United States. Of the 245 individuals who participated in the study (response rate = 45.4%), the majority had difficulty with identifying weaknesses in model performance analysis. Further studies examining educational interventions addressing such ML topics are warranted.
How is mobile health technology transforming physician–nurse collaboration?
Authors: Dongmo Fotsing Laurena N. , Pang Emily M. , Shieh Lisa
Published: September 2021

The integration of mobile health technologies in medical practice has the potential to promote in‐person, high‐quality care. We examine the impact of Voalte, a healthcare‐specific mobile application, on bedside rounding and care coordination. A cross‐sectional survey was conducted on 71 medical ward‐based nurses from a quaternary‐care academic centre, capturing 183 rounding events. The frequency of physician–nurse overlap at the bedside was 50.3%, representing a >20% increase when compared with the 2018 baseline before Voalte's introduction. Our results show that mobile health technologies can strengthen inpatient medicine workflows and interdisciplinary collaboration when implemented successfully.
Improved thermal stability of the near‐infrared Al‐modulated Zn3Ga2GeO8: Cr3+ phosphors for plant growth applications
Authors: Lv Hongyu , Liu Zhichao , Wang Chao , Cai Yiyu , Zhang Hao , Wang Ting , Yang Xiuxia , Yu Xue , Qiu Jianbei , Xu Xuhui
Published: September 2021

The exploration of the high thermal stability near‐infrared (NIR) phosphors is significantly crucial for the development of plant lighting. However, NIR phosphors suffer from the poor chemical and thermal stability, which severely limits their long‐term operation. Here, the successful improvement of luminous intensity (149.5%) and thermal stability at 423 K of Zn3Ga2GeO8 (ZGGO): Cr3+ phosphors is achieved for the introduction of Al3+ ions into the host. The release of carriers in deep traps inhibits the emission loss for the thermal disturbance. Furthermore, an NIR light emitting diodes (LEDs) lamp is explored by combining the optimized Zn3Ga1.1675Al0.8GeO8: 0.0325Cr3+ phosphors with a commercial 460 nm blue chip, and the emission band can match well with the absorption bands of photosynthetic pigments and the phytochrome (PR and PFR) of plants. The explored LEDs lamp further determines the growth and the pheromone content of the involved plants for the participation of the NIR emission originated from Cr3+ ions. Our work provides a promising NIR lamp as plant light with improved thermal stability for long‐term operation.
Reactive binder and aggregate interfacial zones in the mortar of Tomb of Caecilia Metella concrete, 1C BCE, Rome
Authors: Seymour Linda M. , Tamura Nobumichi , Jackson Marie D. , Masic Admir
Published: September 2021

Integrated spectroscopic analyses and synchrotron X‐ray microdiffraction investigations provide insights into the long‐term reactivity of volcanic aggregate components and calcium‐aluminum‐silicate‐hydrate (C‐A‐S‐H) binder in mortar samples from the robust concrete of the sepulchral corridor of the Tomb of Caecilia Metella, 1st C BCE, Rome. The results of innovative micrometer‐scale analytical maps indicate that Pozzolane Rosse tephra components–scoria groundmass, clinopyroxene, and leucite crystals–contributed to pozzolanic production of C‐A‐S‐H binder and then remained reactive long after hydrated lime (Ca(OH)2) was fully consumed. The C‐A‐S‐H binding phase is reorganized into wispy halos and tendril‐like strands, some with nanocrystalline preferred orientation or, alternatively, split into elongate features with short silicate chain lengths. These microstructures apparently record chemical and structural destabilization of C‐A‐S‐H during excessive incorporation of Al3+and K+released through leucite dissolution. Resistance to failure may result from the intermittent toughening of interfacial zones of scoriae and clinopyroxene crystals with post‐pozzolanic strätlingite and Al‐tobermorite mineral cements and from long‐term remodeling of the pozzolanic C‐A‐S‐H binding phase. Roman builders’ selection of a leucite‐rich facies of Pozzolane Rosse tephra as aggregate and construction of the tomb in an environment with high surface and ground water exposure apparently increased beneficial hydrologic activity and reactivity in the concrete.
Relationship between lung function impairment, hypertension, and major adverse cardiovascular events: A 10‐year follow‐up study
Authors: Wang Jiaqi , Dai He , Chen Chong , Ding Ganling , Zhang Yongqing , Qin Yu , Zhang Yuqing , Xiang Quanyong
Published: September 2021

Lung function impairment and hypertension, especially hypertension, are risk factors of major adverse cardiovascular events (MACEs). However, the relationships among lung function impairment, hypertension, and MACEs have not been well‐reported. We aimed to investigate the association between lung function and hypertension and MACEs. We studied 6769 people who were a representative sample of the general population in Jiangsu Province using the multi‐stage stratified cluster sampling method. The average age was 51.54 years. Cox proportional hazards models were used to analyze the relationships between the blood pressure status and various types of lung function impairment related to MACEs. Over a follow‐up of 10 years, 236 MACEs occurred. After adjusting for age, sex, BMI, smoking, drinking, education, physical activity, diabetes mellitus, dyslipidemia, creatine and use of antihypertensive drugs, hypertension [hazard ratio (HR) = 2.154, 95% confidence intervals (CI): 1.565–2.966], and restrictive lung function impairment (RLFI) (HR = 1.398, 95% CI: 1.021–1.879) were independently associated with MACEs. Individuals with hypertension and RFLI had the highest risk for MACEs (HR = 2.930, 95% CI: 1.734–4.953) and stroke (HR = 3.296, 95% CI: 1.862–5.832). Moreover, when combined with hypertension, obstructive lung function impairment (OLFI) (HR = 2.376, 95% CI: 1.391–4.056) and mixed lung function impairment (MLFI) (HR = 2.423, 95% CI: 1.203–4.882) were associated with MACEs. There is a synergistic effect of lung function impairment (especially RLFI) and hypertension on MACEs. Therefore, more attention should be paid to the incidence of MACEs in individuals with impaired lung function, especially those who have hypertension.
The structure of sensory afferent compartments in health and disease
Authors: Middleton Steven J. , Perez‐Sanchez Jimena , Dawes John M.
Published: September 2021

Primary sensory neurons are a heterogeneous population of cells able to respond to both innocuous and noxious stimuli. Like most neurons they are highly compartmentalised, allowing them to detect, convey and transfer sensory information. These compartments include specialised sensory endings in the skin, the nodes of Ranvier in myelinated axons, the cell soma and their central terminals in the spinal cord. In this review, we will highlight the importance of these compartments to primary afferent function, describe how these structures are compromised following nerve damage and how this relates to neuropathic pain.
Association between inflammatory bowel disease and risk of abnormalities of uterine cervix
Authors: Cui Yuemei , Jin Xianyu , Zhang Hui , Liu Lifeng
Published: September 2021

Background

Previous studies provided inconsistent results regarding the association between inflammatory bowel disease (IBD) and risk of abnormalities of uterine cervix. The study aimed to make a meta‐analysis to evaluate the association between IBD and risk of abnormalities of uterine cervix.

Methods

Articles published until April 2021 and regarding the association between IBD and risk of abnormalities of uterine cervix were searched in the following databases: PubMed, Web of Science, EMBASE, Medline, and Google Scholar. Odds ratios (ORs) from case–control studies and relative risks (RRs) from cohort studies with their 95% confidence intervals (CIs) were computed to generate a pooled effect size and 95% CI using STATA 12.0 software.

Results

The present study finally included seven cohort studies (including 94 144 IBD patients and 53 661 004 HC) and four case–control studies (including 20 267 cases and 60 034 matched controls). The meta‐analysis indicated a positive association between IBD and risk of abnormalities of uterine cervix with a random‐effects model (OR/RR = 2.46, 95% CI 1.55–3.91, I2 = 91.8%, p < 0.001). However, no significant association between IBD and risk of cervical cancer was showed in the study with a random‐effects model (OR/RR = 1.54, 95% CI 0.83–2.85, I2 = 82.2%, p < 0.001).

Conclusion

In conclusion, IBD is associated with a 146% higher risk of abnormalities of uterine cervix. However, the study demonstrated no significant association between IBD and risk of cervical cancer. Thus, a conventional screening for abnormalities of uterine cervix is essential for IBD patients.
Stable allopolyploidy in a hybrid zone within the Matsukawaura Lagoon (Japan) between Neopyropia yezoensis and Neopyropia tenera (Bangiales, Rhodophyta) and its relevance to speciation mechanisms and crop improvement
Authors: Niwa Kyosuke , Koizumi Yukiho , Iga Hiroshi
Published: September 2021

To confirm the distribution of the allopolyploid and ancestral species in the Matsukawaura Lagoon in a hybrid zone between Neopyropia yezoensis and Neopyropia tenera, molecular marker analyses and culture experiments were performed using collected blades. All the blades examined, except for one blade identified as N. tenera, exhibited nuclear genotypes of both species, but only the chloroplast haplotype of N. yezoensis. In addition, four conchocelis strains were isolated from each of the blades, and they contained genotypes of both N. yezoensis and N. tenera; a conchocelis strain from the sole N. tenera blade was also isolated. Using the conchocelis strains, F1 blades that were produced from archeospores were obtained under laboratory culture and examined by nuclear DNA markers. These results indicated that the collected blades and the examined F1 blades, except for the single N. tenera blade, were allodiploids and that the four conchocelis strains could be allotetraploids derived from interspecific hybridization between N. yezoensis as the maternal strain and N. tenera as the paternal strain. Therefore, most of the Neopyropia blades growing in the Matsukawaura Lagoon are presumed to be from allopolyploid lineages derived from interspecific hybridization. Furthermore, a growth comparison between the allopolyploid strain and the N. tenera strain was carried out under identical culture conditions. The rate of increase in blade length was significantly higher in the allopolyploid hybrid than in the pure N. tenera. The results suggest that further exploration of allopolyploidy in the potential hybrid zones will be needed not only for the investigation of speciation mechanisms in the bladed Bangiales but also for the genetic improvement of the marine crop.
Education, Dietary Intakes and Exercise*
Authors: von Hinke Stephanie
Published: September 2021

This paper examines the relationship between education and health behaviours, focusing on potential offsetting responses between calories in (i.e. dietary intakes) and calories out (i.e. physical activity). It exploits the 1972 British compulsory schooling law that raised the minimum school leaving age from 15 to 16 to estimate the effects of education on diet and exercise around middle age. Using a regression discontinuity design, the findings suggest that the reform led to a worsening of the quality of the diet, with increases in total calories, fats and animal proteins. However, I find that these changes are partially offset by a discontinuous increase in physical activity. Back‐of‐the‐envelope calculations suggest little effect on the balance of calories. As such, the findings show that focusing on the two components of energy balance provides additional information that is concealed in analyses that only use a measure of obesity.
Grounding, Understanding, and Explanation
Authors: Siscoe Robert Weston
Published: September 2021

Starting with the slogan that understanding is a ‘knowledge of causes’, Stephen Grimm and John Greco have argued that understanding comes from a knowledge of dependence relations. Grounding is the trendiest dependence relation on the market, and if Grimm and Greco are correct, then instances of grounding should also give rise to understanding. In this paper, I will show that this prediction is correct – grounding does indeed generate understanding in just the way that Grimm and Greco anticipate. However, grounding examples of understanding also show that Grimm and Greco are not telling the full story when it comes to understanding. Understanding can only be generated by a particular subset of dependence relations – those dependence relations that are also explanatory. Grimm and Greco should thus appeal to a privileged class of dependence relations, relations like grounding that can also give rise to explanation.
Quantification of Conceptual Model Uncertainty in the Modeling of Wet Deposited Atmospheric Pollutants
Authors: Urso Laura , Sy Mouhamadou Moustapha , Gonze Marc‐André , Hartmann Philipp , Steiner Martin
Published: September 2021

Conceptual model uncertainty and parameter uncertainty are dominant contributors to the total uncertainty of a radioecological model output. In the present study the focus is on conceptual model uncertainty, which is often not acknowledged. Conceptual model uncertainty is assessed by subtracting from the total uncertainty of the model output the propagated parameter uncertainty, obtained by means of Bayesian inference analysis. The conceptual model uncertainty is quantified for two process‐based models, which describe the interception of wet deposited pollutants under equilibrium and kinetic conditions, respectively. The natural variability due the chemical valence of the elements considered is accounted for in both models. Quantitative evidence has been obtained that the conceptual model uncertainty can contribute to the total uncertainty budget of the models for interception of wet deposited pollutants at least as much as, if not more than, parameter uncertainty.
Mitogenomic data elucidate the phylogeny and evolution of life strategies in Dermestidae (Coleoptera)
Authors: Motyka Michal , Kusy Dominik , Háva Jiří , Jahodářová Eva , Bílková Renata , Vogler Alfried P. , Bocak Ladislav
Published: September 2021

Dermestidae (Bostrichoidea) exploit diverse food sources including fungal mycelia, but notably they as saprophagous, feeding on decomposing and dried flesh and keratin of animals and plants. Some of them live in spider webs, vertebrate and social insect nests, while others cause damage in human dwellings. Here, we use mitogenomics to reconstruct their phylogeny and evolution of life history strategies. We recovered serial splits of Orphilinae, Thorictinae + Dermestinae, Attageninae, Trinodinae and Megatominae, and we dated the origins of all subfamilies between the Middle Jurassic and Upper Cretaceous. Extant genera started their diversification in the Middle Cretaceous, except for Dermestes that originated in the Eocene. Mycetophagy, the likely feeding style of the common ancestor with Endecatomidae, was retained only by Orphilinae. Since the Late Jurassic, most dermestids have been saprophagous with the preference for desiccated tissue. We infer a scenario of feeding preferences from mycetophagy moving to saprophagy, always depending on food with low water content, followed by the shift from cryptic life in crevices and wood, to commensalism with social Hymenoptera, and ultimately feeding on angiosperm pollen as adults. The dependence on spider larders evolved already in the Early Cretaceous, but lineages with this specialized strategy remained species‐poor. We date the origin of exploitation of vertebrate carcasses to the Eocene when modern mammalian fauna became dominant. The diversification of Megatominae (62% of known dermestids) and Attagenus Latreille (17%) coincides with the radiation of angiosperms.
Contribution, Replaceability and the Meaning of Our Lives
Authors: Smilansky Saul
Published: September 2021

I explore some surprising results concerning positive individual contributions, focusing on those made in one's job or in the position one holds. The replaceability of most people on the job or in positions of influence threatens our common sense notion of contribution. Two concepts of contribution are distinguished, and help to limit the sense of paradox, but do not completely eliminate it. The ideal of making a contribution that would not be done were one not to do it is seen as both highly threatening and potentially very important for acquiring meaning in one's life. Finally, some hazards of our conclusions are seen to lead to thoughts about the dangers of open disclosure.
A novel Medicago truncatula calmodulin‐like protein (MtCML42) regulates cold tolerance and flowering time
Authors: Sun Qiguo , Huang Risheng , Zhu Haifeng , Sun Yanmei , Guo Zhenfei
Published: September 2021

Calmodulin‐like proteins (CMLs) are one of the Ca2+ sensors in plants, but the functions of most CMLs remain unknown. The regulation of cold tolerance and flowering time by MtCML42 in Medicago truncatula and the underlying mechanisms were investigated using MtCML42‐overexpressing plants and cml42 Medicago mutants with a Tnt1 retrotransposon insertion. Compared with the wild type (WT), MtCML42‐overexpressing lines had increased cold tolerance, whereas cml42 mutants showed decreased cold tolerance. The impaired cold tolerance in cml42 could b complemented by MtCML42 expression. The transcript levels of MtCBF1, MtCBF4, MtCOR413, MtCAS15, MtLTI6A, MtGolS1 and MtGolS2 and the concentrations of raffinose and sucrose were increased in response to cold treatment, whereas higher levels were observed in MtCML42‐overexpressing lines and lower levels were observed in cml42 mutants. In addition, early flowering with upregulated MtFTa1 and downregulated MtABI5 transcripts was observed in MtCML42‐overexpressing lines, whereas delayed flowering with downregulated MtFTa1 and upregulated MtABI5 was observed in cml42. MtABI5 expression could complement the flowering phenotype in the Arabidopsis mutant abi5. Our results suggest that MtCML42 positively regulates MtCBF1 and MtCBF4 expression, which in turn upregulates the expression of some COR genes, MtGolS1 and MtGolS2, which leads to raffinose accumulation and increased cold tolerance. MtCML42 regulates flowering time through sequentially downregulating MtABI5 and upregulating MtFTa1 expression.
Plant mitochondria – past, present and future
Authors: Møller Ian Max , Rasmusson Allan G. , Van Aken Olivier
Published: September 2021

The study of plant mitochondria started in earnest around 1950 with the first isolations of mitochondria from animal and plant tissues. The first 35 years were spent establishing the basic properties of plant mitochondria and plant respiration using biochemical and physiological approaches. A number of unique properties (compared to mammalian mitochondria) were observed: (i) the ability to oxidize malate, glycine and cytosolic NAD(P)H at high rates; (ii) the partial insensitivity to rotenone, which turned out to be due to the presence of a second NADH dehydrogenase on the inner surface of the inner mitochondrial membrane in addition to the classical Complex I NADH dehydrogenase; and (iii) the partial insensitivity to cyanide, which turned out to be due to an alternative oxidase, which is also located on the inner surface of the inner mitochondrial membrane, in addition to the classical Complex IV, cytochrome oxidase. With the appearance of molecular biology methods around 1985, followed by genomics, further unique properties were discovered: (iv) plant mitochondrial DNA (mtDNA) is 10–600 times larger than the mammalian mtDNA, yet it only contains approximately 50% more genes; (v) plant mtDNA has kept the standard genetic code, and it has a low divergence rate with respect to point mutations, but a high recombinatorial activity; (vi) mitochondrial mRNA maturation includes a uniquely complex set of activities for processing, splicing and editing (at hundreds of sites); (vii) recombination in mtDNA creates novel reading frames that can produce male sterility; and (viii) plant mitochondria have a large proteome with 2000–3000 different proteins containing many unique proteins such as 200–300 pentatricopeptide repeat proteins. We describe the present and fairly detailed picture of the structure and function of plant mitochondria and how the unique properties make their metabolism more flexible allowing them to be involved in many diverse processes in the plant cell, such as photosynthesis, photorespiration, CAM and C4 metabolism, heat production, temperature control, stress resistance mechanisms, programmed cell death and genomic evolution. However, it is still a challenge to understand how the regulation of metabolism and mtDNA expression works at the cellular level and how retrograde signaling from the mitochondria coordinates all those processes.
Experticia y cognición. Exploración de funciones cognitivas verbales y visoespaciales en arquitectos y psicólogos
Authors: Cervigni Mauricio , Alfonso Guillermo , Deleglise Álvaro , Gallegos Miguel , Martino Pablo
Published: September 2021

Diversas investigaciones han advertido que el ejercicio de algunas profesiones puede conllevar efectos moduladores en la estructura cerebral y el funcionamiento cognitivo. Se presentan los resultados de un estudio exploratorio transversal referente a las modificaciones que las experticias en arquitectura (N = 41, edad: X = 39, DE = 10) y en psicología (N = 40, edad: X = 35, DE = 7) producen sobre procesos cognitivos específicos. El objetivo general fue contribuir a la determinación de perfiles cognitivos diferenciales. Los arquitectos mostraron un mejor rendimiento en tareas que involucran la retención y manipulación de información visoespacial. No se hallaron diferencias significativas en la resolución de tareas verbales. Estos resultados sugieren que la experiencia en arquitectura podría conducir a un desempeño conductual mejorado en procesos cognitivos correspondientes a la memoria de trabajo visoespacial. Se discuten los alcances de la presente exploración y las instancias necesarias para la validación de estas observaciones. Se sugiere la realización de nuevos estudios que integren seguimiento longitudinal y tecnologías de neuroimagen.
Numerical Analysis of Three-Dimensional Heat and Mass Transfer in Cocoa Beans Under a Solar Drying Condition With a Thermal Storage Material
Authors: Komolafe Clement A. , Waheed Mufutau A. , Ezekwem Chidozie , Hii Ching L.
Published: September 2021

This study investigated the numerical analysis of heat and mass transfer during solar drying of cocoa beans with firebrick thermal storage material. The continuity, momentum, energy, and species equations were solved for a three-dimensional ellipsoidal cocoa bean using the finite volume method with the aid of ansys, a computational fluid dynamics software. The simulated and experimental maximum product (cocoa) temperatures of 53 and 53.5 °C, respectively, were in agreement with each other. The results obtained in this study will help the stakeholders in the cocoa processing industries in the design of the drying system, selection of suitable drying conditions, prediction of heat and mass transfer in the drying process of cocoa, enhancement of better quality attributes such as color and flavor, and reduction in the cost of design and time in the drying process.
Reassessment of Computational Tools for the Modeling of Heat Transfer in a Molten UO2 Pool in Natural Convection
Authors: Jamond Claude , Martin Lopez Elena , Chen Xue-Nong , Girault Nathalie , Gubernatis Pierre , Rineiski Andrei
Published: September 2021

This work, performed within the European sodium fast reactor safety measures assessment and research tools (ESFR-SMART) H2020 European project, is part of a larger framework intending to reassess the modeling of heat transfer in molten pools on SCARABEE available experimental results. This paper presents simulation results of the in-pile Bain Fondu (BF1) test, performed within the SCARABEE-N program, using accident source term evaluation code (ASTEC), Sn method implicit multifiel multiphase Eulerien recriticality (SIMMER) III, and SIMMER V simulation tools as well as comparison with its available experimental data. This program was performed in the 1980s in the frame of the Safety Assessment studies of Superphenix sodium-cooled reactor. This test was dedicated to verify the stability of a pure molten UO2 pool under decay heat conditions within natural convection and the long-term resilience of the peripheral fuel crust. The pool was generated in a stainless steel crucible by a progressive heating of a fuel pellet stack through six successive power plateaus. For the benchmark purposes, only the molten pool behavior k the last power plateau, where the pool was the largest and the fuel temperatures the highest, was investigated. Experimental data such as the axial profile of radial heat fluxes and heat transfer from the pool to the surrounding interassembly coolant as well as the axial profile of the peripheral fuel crust thickness were used for the reassessment of the simulation tools. In addition, other variables of interest not measured during the test, such as the radial and axial velocities in the pool, were also benchmarked. Finally, a critical analysis of the correlations and models used in the different simulation tools for the BF1 test modeling is also provided in the paper.
Local Heat Transfer and Friction Measurements in Ribbed Channel at High Reynolds Numbers
Authors: Baybuzenko Igor
Published: September 2021

The power generation industry is targeting heavy duty gas turbine to increase power and efficiency. Hot gas temperature and massflow are continuously being increased. It brings new challenges for the design of cooling systems for turbine blades and vanes. Up to date most of studies of heat transfer in internal cooling channels were in the range of Reynolds numbers below 80,000 for cooling air flow, for example, experimental series done by J. Chin Han et al. since 1985. Actually the range of Reynolds numbers is increased with the increase of total massflow. Extrapolation of available data is not reliable while local distribution of heat transfer coefficients becomes critical in terms of thermal stresses. Only few recent studies deal with the range of Reynolds number above 80,000, for example, in 2009 J. Chin et. al showed results for 45° angled ribs provided only area averaged values for heat transfer coefficient over one pitch and in 2003 R. Bunker showed local distribution for 45° angled ribs only. Within current study the experimental measurements of local heat transfer and friction in ribbed cooling channel were performed for Reynolds numbers in range of 100,000 – 180,000, what fits the parameters of modern and perspective heavy duty gas turbines. Using thermochromic liquid crystal technology the following rib configurations were tested: angled 45°, 60°, 90° and chevron 45°, 60°; pitch to height ratio of 10; rib turbulator height-to-channel hydraulic diameter ratio of 0.083. Maximum averaged heat transfer value was provided by 60° angled ribs. Comparison of local distribution of heat transfer coefficients for considered configurations was performed. Minimum non-uniformness of heat transfer coefficient was provided by chevron ribs, having maximum friction factor. Conjugated thermal-hydraulic analysis for cooled vane for heavy duty gas turbine was performed in order to quantify the effect of local heat transfer coefficient distribution in ribbed cooling channel. Metal temperature calculation was performed for two cases of air side thermal boundary condition application for wall surface between rib-turbulators: averaged value of heat transfer coefficient and detailed local distribution. Comparison of calculated metal temperature for 2 cases shows that usage of locally distributed air side heat transfer coefficient is important and should increase the accuracy of temperature prediction by 50°C. Consideration of local distribution of heat transfer coefficient is important for cooling design of modern heavy duty gas turbine in order to provide acceptable thermal gradients and consequently reach lifetime targets.
Influence of Ambient Pressure on Measured Stiffness and Damping of Radial Gas Foil Bearings
Authors: Wilkes Jason , White Steve
Published: September 2021

As gas bearings have gained popularity, they have been used in a diverse range of applications. In many cases these bearings are used in various process gases at a range of pressures. Although numerous analytical tools exist to predict the behavior of gas bearings in these environments, these tools are challenging to validate. The current work describes a test loop that is capable of measuring rotordynamic force coefficients in a hermetically sealed environment. To the author’s knowledge, this capability is the first of its kind.

To illustrate operation of the test rig, an industrial 3-lobe gas-foil bearing was installed in the test fixture, and operated at pressures from .5–3.5 bara at speeds ranging from 25–65 krpm. The tests show that dynamic coefficients increase with speed and pressure; however, a slight reduction in coefficients were observed at the highest speed under ambient conditions. In addition, sub ambient pressure tests showed higher than ambient stiffness, but comparably low damping in comparison to the other test cases. It is believed that this is the first publication of gas foil bearing coefficients at sub-ambient pressure.
Mechanical Design and Testing of a 2.5 MW sCO2 Compressor Loop
Authors: Cich Stefan D. , Moore J. Jeffrey , Kulhanek Chris , Towler Meera Day , Mortzheim Jason
Published: September 2021

An enabling technology for a successful deployment of the sCO2 close-loop recompression Brayton cycle is the development of a compressor that can maintain high efficiency for a wide range of inlet conditions due to large variation in properties of CO2 operating near its dome. One solution is to develop an internal actuated variable Inlet Guide Vane (IGV) system that can maintain high efficiency in the main and re-compressor with varying inlet temperature. A compressor for this system has recently been manufactured and tested at various operating conditions to determine its compression efficiency. This compressor was developed with funding from the US DOE Apollo program and industry partners. This paper will focus on the design and testing of the main compressor operating near the CO2 dome. It will look at design challenges that went into some of the decisions for rotor and case construction and how that can affect the mechanical and aerodynamic performance of the compressor. This paper will also go into results from testing at the various operating conditions and how the change in density of CO2 affected rotordynamics and overall performance of the machine. Results will be compared to expected performance and how design changes were implanted to properly counter challenges during testing.
Retracted: “Aerodynamic Design and Rig Test Validation of a High Flow Coefficient Process Centrifugal Compressor Stage” [ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition, Volume 2D, Virtual, Online, June 7–11, 2021, Conference Sponsors: International Gas Turbine Institute, ISBN: 978-0-7918-8493-5, Copyright © 2021 by ASME. Paper No. GT2021-04373, V02DT37A001; 14 pages; doi: 10.1115/GT2021-04373]
Authors: ASME
Published: September 2021

This paper was erroneously published in ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition, Vol. 2D and removed on October 13, 2021.

Copyright © 2021 by ASME
Gradient-Free Optimization in Thermoacoustics: Application to A Low-Order Model
Authors: Reumschüssel Johann Moritz , von Saldern Jakob G. R. , Li Yiqing , Paschereit Christian Oliver , Orchini Alessandro
Published: September 2021

Machine learning and automatized routines for parameter optimization have experienced a surge in development in the past years, mostly caused by the increasing availability of computing capacity. Gradient-free optimization can avoid cumbersome theoretical studies as input parameters are purely adapted based on output data. As no knowledge about the objective function is provided to the algorithms, this approach might reveal unconventional solutions to complex problems that were out of scope of classical solution strategies. In this study, the potential of these optimization methods on thermoacoustic problems is examined. The optimization algorithms are applied to a generic low-order thermoacoustic can-combustor model with several fuel injectors at different locations. We use three optimization algorithms — the well established Downhill Simplex Method, the recently proposed Explorative Gradient Method, and an evolutionary algorithm — to find optimal fuel distributions across the fuel lines while maintaining the amount of consumed fuel constant. The objective is to have minimal pulsation amplitudes. We compare the results and efficiency of the gradient-free algorithms. Additionally, we employ model-based linear stability analysis to calculate the growth rates of the dominant thermoacoustic modes. This allows us to highlight general and thermoacoustic-specific features of the optimization methods and results. The findings of this study show the potential of gradient-free optimization methods on combustor design for tackling thermoacoustic problems, and motivate further research in this direction.
Confidence in Flame Impulse Response Estimation From LES With Uncertain Thermal Boundary Conditions
Authors: Kulkarni Sagar , Guo Shuai , Silva Camilo F. , Polifke Wolfgang
Published: September 2021

Thermoacoustic stability analysis is an essential part of the engine development process. Typically, thermoacoustic stability is determined by hybrid approaches such as network models or Helmholtz solvers. These approaches require information on the flame dynamic response. The combined approach of advanced System identification (SI) and Large Eddy Simulation (LES) is an efficient strategy to compute the flame dynamic response to flow perturbation in terms of the Finite Impulse Response (FIR). The identified FIR is uncertain due in part to the aleatoric uncertainties caused by applying SI on systems with combustion noise and partly due to epistemic uncertainties caused by lack of knowledge of operating or boundary conditions. Carrying out traditional uncertainty quantification techniques, such as Monte Carlo, in the framework of LES/SI would be computationally prohibitive. As a result, the present paper proposes a methodology to build a surrogate model in the presence of both aleatoric and epistemic uncertainties. More specifically, we propose a univariate Gaussian Process (GP) surrogate model, where the final trained GP takes into account the uncertainty of SI and the uncertainty in the combustor back plate temperature, which is known to have considerable impact on the flame dynamics. The GP model is trained on the FIRs obtained from the LES/SI of turbulent pre-mixed swirled combustor at different combustor back plate temperatures. Due to the change in the combustor back plate temperature the flame topology changes, which in turn influences the FIR. The trained GP model is successful in interpolating the FIR with confidence intervals covering the “true” FIR from LES/SI.
Numerical Evaluation of Losses in Shrouded and Cantilevered Stators of a Multi-Stage Axial Compressor
Authors: De Dominicis Ilaria , Robens Sebastian , Gümmer Volker
Published: September 2021

The loss coefficient based only on the stagnation pressure has traditionally been used in the analysis of axial compressors for the comparison between shrouded and cantilevered stator configurations. In recent years, engineers have been able to perform more detailed Computational Fluid Dynamics simulations, allowing them to resolve the flow field in the leakage paths. The two stator hub designs are, however, affected by the rotating surfaces in a different way: in cantilevered stators, the relative rotation between the stator and the hub imparts energy to the hub flow, whereas in shrouded stators, the rotating inner leakage surface imparts energy to the seal cavity leakage flow.

The aim of this work is to analyze the performance of a multi-stage axial compressor featuring a change of stator hub configuration, by employing both the conventional loss coefficient based on the stagnation pressure and the loss coefficient based on the entropy change. It is shown, that in the evaluation of the losses of a multi-stage axial machine, it is essential to consider the different 3D distributions of stagnation temperature resulting from the two stator hub configurations, which are transferred to the downstream rows.
Automatically Designed Deep Gaussian Process for Turbomachinery Application
Authors: Jin Yuan , Chai Jin , Jung Olivier
Published: September 2021

Thanks to their flexibility and robustness to overfitting, Gaussian Processes (GPs) are widely used as black-box function approximators. Deep Gaussian Processes (DGPs) are multilayer generations of GPs. The deep architecture alleviates the kernel dependance of GPs, while complicates model inference. The so-called doubly stochastic variational approach, which does not force the independence between layers, shows its effectiveness in large dataset classification and regression in the literature. Meanwhile, similar to deep neural network, DGPs also require application-specific architecture. In addition, the doubly stochastic process introduces extra hyperparameters, which further increases the difficulty in model definition and training. In this study, we apply doubly stochastic variational inference DGP as surrogate model on high-dimensional structural data regression drawn from turbomachinery area. A discrete optimizer, which is based on classification discriminating good solutions from bad ones, is utilized to realize automatic DGP model design and tuning. Empirical experiments are performed firstly on analytical functions to demonstrate the capability of DPGs in high-dimensional and non-stationary data handling. Two industrial turbomachinery problems with respectively 80 and 180 input dimensions are addressed. The first application consists in a turbine frame design problem. In the second application, DGP is used to describe the correlation between 3D blade profiles of a multi-stage low pressure turbine and the corresponding turbine total-total efficiency. Through these two applications, we show the applicability of the proposed automatically designed DGPs in turbomachinery area by highlighting their outperformance with respect to classic GPs.
Improvement of Surface Cracking Risks by Controlling Dilution of Cobalt-Based Hardfacings
Authors: Yokoyama Takashi , Kurimura Takayuki , Sakakibara Noriyuki , Suzuki Fumiyuki
Published: September 2021

Cobalt-based hardfacings have been widely applied to the main valve seats of steam turbines for the purpose of improving durability. With the aim of decreasing the surface cracking risks of the hardfacings, the dilution of the hardfacing on their surface was controlled and the properties of the dilution-controlled materials were investigated in this study. Mixtures of cobalt-based hardfacings and base materials were cast in order to simulate the dilution of base material to hardfacing, which occurs in the process such as PTA welding. It was confirmed that the grain size matched that produced by PTA welding by controlling the cooling rate. To investigate the effect of aging on the microstructures and mechanical properties of the cast samples, the samples were aged in electric furnaces where the temperature was controlled to the steam temperature of steam turbines and above. The test results show that the phase transitioned from face-centered cubic to hexagonal closed-packed in low-dilution samples, while carbides precipitated along the grain boundaries in high-dilution samples after aging. Both samples showed an increase in hardness and reduction in ductility and fracture toughness. In addition, the variation in microstructures and strength properties was suppressed for a 20 % dilution sample. To validate the influence of dilution as investigated with the cast samples, test specimens were machined from the surface and bottom layers of multi-layered hardfacing that had different dilutions by PTA welding. It was confirmed that the influence of dilution on the strength properties of hardfacing layers had a similar tendency to the cast samples. The results above lead to the possibility of reducing the surface cracking risks by controlling the dilution of hardfacings and suppressing embrittlement after aging. We have applied dilution-controlled hardfacings to steam valves and successfully reduced surface cracking.