bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationship between saliva protein composition and 6‐n‐Propylthiouracil bitter taste responsiveness in young adults
Authors: Rodrigues L. , da Costa G. , Cordeiro C. , Pinheiro C. C. , Amado F. , Lamy E.
Published: July 2017

6‐n‐propylthiouracil (PROP) is widely used in nutritional and health studies. However, only a limited number of studies have compared saliva composition between PROP taster phenotypes. The main aim of this work was to assess the relationship between saliva proteome and PROP responsiveness in young adults (N = 152) taking into account body mass index (BMI) and sex. SDS‐PAGE and 2‐DE protein profiles of saliva collected before and after PROP stimulation were compared between super‐tasters (ST) and non‐tasters (NT) and proteins of interest identified by mass spectrometry. These groups were also compared for their salivary levels of type‐S cystatins and carbonic anhydrase VI (CA‐VI). The relationship between salivary proteome and PROP responsiveness was affected by sex and BMI. Even so, immunoglobulin chains increased and prolactin‐inducible protein and type‐S cystatins decreased in ST group, both in men and women. Only when the subject's weight was considered in the analysis was it possible to observe differences between ST and NT in the levels of type‐S cystatins, suggesting that BMI has an effect on the relationship between these salivary proteins and bitter taste response. PROP stimulation induced changes in the amounts of salivary amylase, cystatins, and CA‐VI, which differed between ST and NT and may be important in differentiating PROP responsiveness groups. Among the proteins identified, most of the isoforms associated with PROP responsiveness had low pI.

Practical applications

Inter‐individual differences in 6‐n‐propylthiouracil (PROP) responsiveness correspond to the most studied variations in bitterness perception and have been accepted as a general marker of oral chemosensory sensitivity. Differences in PROP phenotype appears to be related to food preferences and dietary behavior. The mechanisms involved in inter‐individual variation in bitter taste perception are complex and are not completely explained by genetics. Identifying salivary constituents potentially involved in PROP responsiveness can increase the understanding of taste function and consequently food acceptance. Moreover, it is important to know whether factors such as weight status and/or sex affect the way in which saliva influences taste perception.
Comparative plasma and interstitial fluid pharmacokinetics of flunixin meglumine and ceftiofur hydrochloride following individual and co‐administration in dairy cows
Authors: Gorden P. J. , Kleinhenz M. D. , Wulf L. W. , Rajewski S. J. , Wang C. , Gehring R. , Coetzee J. F.
Published: July 2017

Ceftiofur (CEF) and flunixin meglumine (FLU) are two drugs approved for use in beef and dairy cattle that are frequently used in combination for many diseases. These two drugs are the most commonly used drugs in dairy cattle in their respective drug classes. Two research groups have recently published manuscripts demonstrating altered pharmacokinetics ofFLUandCEFin cows affected with naturally occurring mastitis. The objective of this study was to determine whether pharmacokinetics of flunixin meglumine administered intravenously or intramuscularly administered ceftiofur hydrochloride would be altered when co‐administered versus individual administration to healthy dairy cattle. Ten cows were utilized in a three‐period, three‐treatment crossover design, with all cows receiving each treatment one time with a 10‐day washout period between treatments. Following treatment, plasma and interstitial fluid samples were collected and stored for later analysis. Additionally, plasma ultrafiltrate was collected using microcentrifugation to determine plasma protein binding of each drug. Drug concentrations in plasma, plasma ultrafiltrate, and interstitial fluid were determined using high‐pressure liquid chromatography coupled with mass spectrometry. The results of this trial indicate that drug interactions betweenFLUandCEFdo not occur when the two drugs are administered simultaneously in healthy cattle. Further work is needed to determine whether this relationship is maintained in the presence of severe disease.
Intraoperative ultrasound for prediction of hepatocellular carcinoma biological behaviour: Prospective comparison with pathology
Authors: Santambrogio Roberto , Cigala Claudia , Barabino Matteo , Maggioni Marco , Scifo Giovanna , Bruno Savino , Bertolini Emanuela , Opocher Enrico , Bulfamante Gaetano
Published: July 2017

Background & Aims

Preoperative prediction of both microinvasive hepatocellular carcinoma and histological grade of hepatocellular carcinoma is pivotal to treatment planning and prognostication. The aim of this study was to evaluate whether some intraoperative ultrasound features correlate with both the presence of same histological patterns and differentiation grade of hepatocellular carcinoma on the histological features of the primary resected tumour.

Methods

All patients with single, small hepatocellular carcinoma that underwent hepatic resection were included in this prospective double‐blind study: the intraoperative ultrasound patterns of nodule were registered and compared with similar histological features.

Results

A total of 179 patients were enclosed in this study: 97 (54%) patients (34% in HCC ≤2 cm) had a microinvasive hepatocellular carcinoma at ultrasound examination, while 82 (46%) patients (41% in HCC ≤2 cm) at histological evaluation. Statistical analysis showed that diameters ≤2 cm, presence of satellites and microinvasive hepatocellular carcinoma at ultrasound examination were the variables with the strongest association with the histological findings. In the multivariate analysis, the vascular microinfiltration and infiltrative hepatocellular carcinoma aspect were independent predictors for grading.

Conclusions

In patients with cirrhosis and hepatocellular carcinoma, the prevalence of microinvasive hepatocellular carcinoma is high, even in cases of HCC ≤2 cm. Intraoperative ultrasound findings strongly correlated with histopathological criteria in detecting microinvasive patterns and are useful to predict neoplastic differentiation. The knowledge of these features prior to treatment are highly desired (this can be obtained by an intraoperative ultrasound examination), as they could help in providing optimal management of patients with hepatocellular carcinoma.
Demography and genome divergence of lake and stream populations of an East African cichlid fish
Authors: Egger Bernd , Roesti Marius , Böhne Astrid , Roth Olivia , Salzburger Walter
Published: July 2017

Disentangling the processes and mechanisms underlying adaptive diversification is facilitated by the comparative study of replicate population pairs that have diverged along a similar environmental gradient. Such a setting is realized in a cichlid fish from southern Lake Tanganyika, Astatotilapia burtoni, which occurs within the lake proper as well as in various affluent rivers. Previously, we demonstrated that independent lake and stream populations show similar adaptations to the two habitat regimes. However, little is known about the evolutionary and demographic history of the A. burtoni populations in question and the patterns of genome divergence among them. Here, we apply restriction site‐associated DNA sequencing (RADseq) to examine the evolutionary history, the population structure and genomic differentiation of lake and stream populations in A. burtoni. A phylogenetic reconstruction based on genome‐wide molecular data largely resolved the evolutionary relationships among populations, allowing us to re‐evaluate the independence of replicate lake–stream population clusters. Further, we detected a strong pattern of isolation by distance, with baseline genomic divergence increasing with geographic distance and decreasing with the level of gene flow between lake and stream populations. Genome divergence patterns were heterogeneous and inconsistent among lake‐stream population clusters, which is explained by differences in divergence times, levels of gene flow and local selection regimes. In line with the latter, we only detected consistent outlier loci when the most divergent lake–stream population pair was excluded. Several of the thus identified candidate genes have inferred functions in immune and neuronal systems and show differences in gene expression between lake and stream populations.
Empathy and the Limits of Thought Experiments
Authors: Ramirez Erick
Published: July 2017

This article criticizes what it calls perspectival thought experiments, which require subjects to mentally simulate a perspective before making judgments from within it. Examples include Judith Thomson's violinist analogy, Philippa Foot's trolley problem, and Bernard Williams's Jim case. The article argues that advances in the philosophical and psychological study of empathy suggest that the simulative capacities required by perspectival thought experiments are all but impossible. These thought experiments require agents to consciously simulate necessarily unconscious features of subjectivity. To complete these experiments subjects must deploy theory‐theoretical frameworks to predict what they think they would (or ought to) do. These outputs, however, systematically mislead subjects and are highly prone to error. They are of negligible probative value, and this bodes poorly for their continued use. The article ends with two suggestions. First, many thought experiments are not problematically perspectival. Second, it should be possible to carry out “in‐their‐shoes” perspectival thought experiments by off‐loading simulations onto virtual environments into which philosophers place subjects.
The Cultural Definition of Art
Authors: Fokt Simon
Published: July 2017

Most modern definitions of art fail to successfully address the issue of the ever‐changing nature of art, and rarely even attempt to provide an account that would be valid in more than just the modern Western context. This article develops a new theory that preserves the advantages of its predecessors, solves or avoids their problems, and has a scope wide enough to account for art of different times and cultures. It argues that an object is art in a given context iff some person(s) culturally competent in this context have afforded it the status of a candidate for appreciation for reasons considered good in this context. This weakly institutional view is supplemented by auxiliary definitions explaining the notions of cultural contexts, competence, and good reasons for affording the status. The relativisation to contexts brings increased explanatory power and scope, and the ability to account for the diversity of art.
Trust as a Meta‐Emotion
Authors: Belli Simone , Broncano Fernando
Published: July 2017

The aim of this article is to present trust as a meta‐emotion, such that it is an emotion that precedes first‐order emotions. It examines how trust can be considered a meta‐emotion by establishing criteria for identifying trust as a meta‐emotion. How trust plays out differently in aesthetic and ordinary contexts can provide another mode for investigating meta‐emotions. The article illustrates how it is possible to recognize these meta‐emotions in narratives. Finally, it presents one of the aims of trust, sharing knowledge between agents, when someone who provides testimony shares knowledge in an epistemic trust process with others. It shows a relationship construction between subjects and objects thanks to the trust, a meta‐emotion that represents emotional ties between subjects to achieve another emotion.
FungiScope™—Global Emerging Fungal Infection Registry
Authors: Seidel Danila , Durán Graeff Luisa A. , Vehreschild Maria J. G. T. , Wisplinghoff Hilmar , Ziegler Maren , Vehreschild J Janne , Liss Blasius , Hamprecht Axel , Köhler Philipp , Racil Zdenek , Klimko Nikolay , Sheppard Donald C. , Herbrecht Raoul , Chowdhary Anuradha , Cornely Oliver A. , FungiScope Group
Published: July 2017

Rare invasive fungal diseases (IFD) are challenging for the treating physicians because of their unspecific clinical presentation, as well as the lack of standardised diagnostic and effective treatment strategies. Late onset of treatment and inappropriate medication is associated with high mortality, thus, urging the need for a better understanding of these diseases. The purpose of FungiScope™ is to continuously collect clinical information and specimens to improve the knowledge on epidemiology and eventually improve patient management of these orphan diseases. FungiScope™ was founded in 2003, and today, collaborators from 66 countries support the registry. So far, clinical data of 794 cases have been entered using a web‐based approach. Within the growing network of experts, new collaborations developed, leading to several publications of comprehensive analyses of patient subgroups identified from the registry. Data extracted from FungiScope™ have also been used as the sole control group for the approval of a new antifungal drug. Due to the rarity of these diseases, a global registry is an appropriate method of pooling the scarce and scattered information. Joining efforts across medical specialities and geographical borders is key for researching rare IFD. Here, we describe the structure and management of the FungiScope™ registry.
Swimming pools and fungi: An epidemiology survey in Polish indoor swimming facilities
Authors: Jankowski Marek , Charemska Anna , Czajkowski Rafał
Published: July 2017

Environmental conditions for swimming facilities may support fungal growth and also may represent a biological risk for users. However, since previously published studies both cleaning procedures and sanitary regulations are likely to have been improved. The aim of the study was to examine whether attendance to public swimming pools was still a risk factor for fungal infection of the skin in Poland. We investigated the occurrence of mycotic species, in a sample from Polish swimming pools. Detection and identification of isolated species were achieved by cultural and morphological methods. Study revealed high incidence of yeast and yeast‐like fungi. Candida spp. and Rhodotorula rubra were commonly detected, followed by Aspergillus spp. and Trichophyton mentagrophytes. Surprisingly, the prevalence of clinically important species isolated from swimming pool environments did not reflect prevalence of those species in Polish population. The present results are in agreement with previous research and support that swimming pools remain an important reservoir of clinically important fungi, yet the exposure associated with swimming pools may not be a major source of dermatophytic infection in Poland.
Environmentally and behaviourally mediated co‐occurrence of functional traits in bird communities of tropical forest fragments
Authors: Ulrich Werner , Banks‐Leite Cristina , De Coster Greet , Habel Jan Christian , Matheve Hans , Newmark William D. , Tobias Joseph A. , Lens Luc
Published: July 2017

Two major theories of community assembly – based on the assumption of ‘limiting similarity’ or ‘habitat filtering’, respectively – predict contrasting patterns in the spatial arrangement of functional traits. Previous analyses have made progress in testing these predictions and identifying underlying processes, but have also pointed to theoretical as well as methodological shortcomings. Here we applied a recently developed methodology for spatially explicit analysis of phylogenetic meta‐community structure to study the pattern of co‐occurrence of functional traits in Afrotropical and Neotropical bird species inhabiting forest fragments. Focusing separately on locomotory, dietary, and dispersal traits, we tested whether environmental filtering causes spatial clustering, or competition leads to spatial segregation as predicted by limiting similarity theory. We detected significant segregation of species co‐occurrences in African fragments, but not in the Neotropical ones. Interspecific competition had a higher impact on trait co‐occurrence than filter effects, yet no single functional trait was able to explain the observed degree of spatial segregation among species. Despite high regional variability spanning from spatial segregation to aggregation, we found a consistent tendency for a clustered spatial patterning of functional traits among communities in fragmented landscapes, particularly in non‐territorial species. Overall, we show that behavioural effects, such as territoriality, and environmental effects, such as the area of forest remnants or properties of the landscape matrix in which they are embedded, can strongly affect the pattern of trait co‐occurrence. Our findings suggest that trait‐based analyses of community structure should include behavioural and environmental covariates, and we here provide an appropriate method for linking functional traits, species ecology and environmental conditions to clarify the drivers underlying spatial patterns of species co‐occurrence.
Feeding behaviour of a new worm (Priapulida) from the Sirius Passet Lagerstätte (Cambrian Series 2, Stage 3) of North Greenland (Laurentia)
Authors: Peel John S.
Published: July 2017

Singuuriqia simoni gen. et sp. nov. represents the first record of a priapulid worm from the Sirius Passet Lagerstätte (Cambrian Series 2, Stage 3) of North Greenland (Laurentia). It is defined by an unusually broad, longitudinally folded, foregut which tapers through the pharynx towards the anterior mouth; posteriorly, the same longitudinal folding is evident in the narrow gut. The slender, smooth, trunk in the unique specimen passes anteriorly into an oval proboscis which culminates in a smooth, extensible, pharynx with pharyngeal teeth. The capacity for substantial expansion of the foregut permitted rapid ingestion of food prior to digestion at leisure. Cololites suggest both carnivorous and deposit feeding behaviour, indicating that Singuuriqia, like the present day Priapulus, was probably omnivorous.
Medicago truncatula Zinc‐Iron Permease6 provides zinc to rhizobia‐infected nodule cells
Authors: Abreu Isidro , Saéz Ángela , Castro‐Rodríguez Rosario , Escudero Viviana , Rodríguez‐Haas Benjamín , Senovilla Marta , Larue Camille , Grolimund Daniel , Tejada‐Jiménez Manuel , Imperial Juan , González‐Guerrero Manuel
Published: July 2017

Zinc is a micronutrient required for symbiotic nitrogen fixation. It has been proposed that in model legume Medicago truncatula, zinc is delivered by the root vasculature into the nodule and released in the infection/differentiation zone. There, transporters must introduce this element into rhizobia‐infected cells to metallate the apoproteins that use zinc as a cofactor. MtZIP6 (Medtr4g083570) is an M. truncatula Zinc‐Iron Permease (ZIP) that is expressed only in roots and nodules, with the highest expression levels in the infection/differentiation zone. Immunolocalization studies indicate that it is located in the plasma membrane of nodule rhizobia‐infected cells. Down‐regulating MtZIP6 expression levels with RNAi does not result in any strong phenotype when plants are fed mineral nitrogen. However, these plants displayed severe growth defects when they depended on nitrogen fixed by their nodules, losing of 80% of their nitrogenase activity. The reduction of this activity was likely an indirect effect of zinc being retained in the infection/differentiation zone and not reaching the cytosol of rhizobia‐infected cells. These data are consistent with a model in which MtZIP6 would be responsible for zinc uptake by rhizobia‐infected nodule cells in the infection/differentiation zone.
Molluscum Contagiosum‐Like Presentation of Langerhans Cell Histiocytosis: A Case and Review
Authors: Karpman Matthew S. , AlJasser Mohammed I. , Lam Joseph M.
Published: July 2017

Langerhans cell histiocytosis (LCH) is a rare disorder characterized by clonal proliferation of Langerhans cells in the skin. A molluscum‐like presentation of cutaneous LCH is rare but important to consider for examination and management. We present an atypical molluscum‐like LCH case and review the literature for common features of this unusual presentation.
Offshore Oil, Environmental Movements, and the Oil‐Tourism Interface: The Old Harry Conflict on Canada's East Coast
Authors: Stoddart Mark C. J. , Graham Paula
Published: July 2017

Offshore oil development and nature‐based tourism offer alternative ways of living with and making use of coastal environments. We analyze a recent controversy over offshore oil extraction in the Gulf of St. Lawrence, in eastern Canada, and identify key points of alignment between environmentalism and the tourism industry that structure resistance to oil development. Our results are based on interviews with tourism operators, government, environmental groups, and recreational organizations, as well as an analysis of key Web sites and Web 2.0 content. Four discourses are used to challenge the normal separation of offshore oil and tourism development in Atlantic Canada: wilderness and wildlife; ecological risks of oil disaster; protecting existing social–ecological networks; and contesting political jurisdiction. Our findings show that the ecological and social value of the Gulf of St. Lawrence is used to justify opposition to oil development in the region. However, the project‐specific nature of this opposition neglects larger questions of social–environmental sustainability in an oil‐dependent political ecology.
Heterogeneity in kinesin function
Authors: Reddy Babu J.N. , Tripathy Suvranta , Vershinin Michael , Tanenbaum Marvin E. , Xu Jing , Mattson‐Hoss Michelle , Arabi Karim , Chapman Dail , Doolin Tory , Hyeon Changbong , Gross Steven P.
Published: July 2017

The kinesin family proteins are often studied as prototypical molecular motors; a deeper understanding of them can illuminate regulation of intracellular transport. It is typically assumed that they function identically. Here we find that this assumption of homogeneous function appears incorrect: variation among motors’ velocities in vivo and in vitro is larger than the stochastic variation expected for an ensemble of “identical” motors. When moving on microtubules, slow and fast motors are persistently slow, and fast, respectively. We develop theory that provides quantitative criteria to determine whether the observed single‐molecule variation is too large to be generated from an ensemble of identical molecules. To analyze such heterogeneity, we group traces into homogeneous sub‐ensembles. Motility studies varying the temperature, pH and glycerol concentration suggest at least 2 distinct functional states that are independently affected by external conditions. We end by investigating the functional ramifications of such heterogeneity through Monte‐Carlo multi‐motor simulations.
An Investigation of the Relationship between Sportsmanship Behavior of Students in Physical Education Course and Their Respect Level
Authors: Koç Yakup , Yeniçeri Samed
Published: July 2017

The aim of this study is to examine relationship between the physical education course sportspersonship behaviors and respect levels for high school students. The sample of study consists of randomly selected 505 high school students (215 female and 290 male) attending state schools in the province of İstanbul in 2016-2017 academic year. “Physical Education Course Sportspersonship Behavior Scale”, “Respect Scale” and personal information form created by the researcher were used in the study. It was found that the scales was valid and reliable and could be used for high school students. Sportsmanship behaviors significantly differed according to the gender of the students (in favor of the girls), the grade (in favor of 10th grade), school success (in favor of good level) and the type of sports most interested (in favor of physically noncontact sports). It was understood that the scale scores of the students are not significantly different according to the family economic conditions. It was found that physical education course sportspersonship behaviors (Realization of Positive Behavior, Avoidance from Negative Behavior) are significantly related to respect levels (Cosmopolitanism, Communitarianism) positively. And it was seen that the level of respect was a significant predictor of the sportsmanship of the students. It is believed that the implementation of activities aimed at improving the level of respect in schools will be helpful in improving sportsmanship behaviors.
Concurrent electrical cervicomedullary stimulation and cervical transcutaneous spinal direct current stimulation result in a stimulus interaction
Authors: Dongés Siobhan C. , Bai Siwei , Taylor Janet L.
Published: July 2017

New Findings

What is the central question of this study?

We previously showed that the motor pathway is not modified after cervical transcutaneous spinal direct current stimulation (tsDCS) applied using anterior–posterior electrodes. Here, we examine the motor pathway during stimulation.

What is the main finding and its importance?

We show that electrically elicited muscle responses to cervicomedullary stimulation are modified during tsDCS, whereas magnetically elicited responses are not. Modelling reveals electrical field modifications during concurrent tsDCS and electrical cervicomedullary stimulation. Changes in muscle response probably result from electrical field modifications rather than physiological changes. Care should be taken when applying electrical stimuli simultaneously.

Transcutaneous spinal direct current stimulation (tsDCS) can modulate neuronal excitability within the human spinal cord; however, few studies have used tsDCS at a cervical level. This study aimed to characterize cervical tsDCS further by observing its acute effects on motor responses to transcranial magnetic stimulation and cervicomedullary stimulation. In both studies 1 and 2, participants (study 1, n = 8, four female; and study 2, n = 8, three female) received two periods of 10 min, 3 mA cervical tsDCS on the same day through electrodes placed in an anterior–posterior configuration over the neck; one period with the cathode posterior (c‐tsDCS) and the other with the anode posterior (a‐tsDCS). In study 1, electrically elicited cervicomedullary motor evoked potentials (eCMEPs) and transcranial magnetic stimulation‐elicited motor evoked potentials (MEPs) were measured in biceps brachii and flexor carpi radialis before, during and after each tsDCS period. In study 2, eCMEPs and magnetically elicited CMEPs (mCMEPs) were measured before, during and after each tsDCS period. For study 3, computational modelling was used to observe possible interactions of cervical tsDCS and electrical cervicomedullary stimulation. Studies 1 and 2 revealed that eCMEPs were larger during c‐tsDCS and smaller during a‐tsDCS compared with those elicited when tsDCS was off (P < 0.05), with no changes in MEPs or mCMEPs. Modelling revealed that eCMEP changes might result from modifications of the electrical field direction and magnitude when combined with cervical tsDCS. Bidirectional eCMEP changes are likely to be caused by an interaction between cervical tsDCS and electrical cervicomedullary stimulation; therefore, care should be taken when combining such electrical stimuli in close proximity.
Blunted cerebral vascular responsiveness to hypercapnia in obese individuals
Authors: Hurr Chansol , Patik Jordan C. , Kim KiYoung , Brothers R. Matthew
Published: July 2017

New Findings

What is the central question of this study?

Is there a difference in the cerebral vascular response to rebreathing‐induced hypercapnia between obese and lean individuals?

What is the main finding and its importance?

The main finding is that obese individuals have an attenuated increase in cerebral vascular conductance during hypercapnia relative to lean individuals. This finding suggests cerebral vascular dysfunction in this population, which might contribute to the greater prevalence of cerebral vascular and neurocognitive disease in this population.

Obesity increases the risk of cardiovascular disease by >45%. Furthermore, obesity is a contributory factor to cognitive impairment and Alzheimer's disease. The mechanisms accounting for this increased disease risk have not been clarified. This study tested the hypothesis that the total range of change (a) in cerebral blood velocity (CBV) and cerebral vascular conductance (CVCI) and the maximal (y0) CBV and CVCI achieved during rebreathing‐induced hypercapnia would be attenuated in obese individuals. Sixteen lean and 15 obese individuals participated. The magnitude of rebreathing‐induced hypercapnia was similar between groups (lean, ∆15 ± 3 mmHg versus obese, ∆15 ± 2 mmHg; P = 0.82). The total range of change in CBV during rebreathing (a; expressed as a percentage) was similar between groups (lean, 91 ± 24% versus obese, 76 ± 19%, P = 0.07), whereas the total range of change in CVCI during rebreathing (a; expressed as a percentage) was attenuated in the obese individuals (lean, 71 ± 20% versus obese, 51 ± 15%, P < 0.01). Likewise, the maximal increase in CBV during rebreathing (y0; expressed as a percentage) was similar between groups (lean, 189 ± 22% versus obese, 179 ± 20%, P = 0.20), whereas the maximal increase in CVCI during rebreathing (y0; expressed as a percentage) was attenuated in the obese individuals (lean, 172 ± 19% versus obese, 155 ± 17 %, P = 0.01). These data indicate that the cerebral vascular response to rebreathing‐induced hypercapnia is attenuated in obese individuals. This impairment might be a factor contributing to the elevated cerebral vascular and neurocognitive disease risk in this population.
Interlaminar Stresses in Composite Laminates Subjected to Twisting Deformation
Authors: Goodsell Johnathan , Peng Bo , Byron Pipes R. , Yu Wenbin
Published: July 2017

The interlaminar stress in angle-ply and cross-ply composite laminates subjected to twisting deformation are investigated. Two mechanisms of interlaminar load transfer have been developed by studying the angle-ply laminate and the cross-ply laminate subjected to uniform axial extension, thermoelastic deformation and anticlastic bending deformation. In the present, these mechanisms are investigated in laminates subjected to twisting deformation. It is shown that the mechanisms of interlaminar load transfer in twisting deformation are identical to those previously investigated, though they arise from different causes. Furthermore, a unified treatment of the mechanisms of interlaminar load transfer is presented for the angle-ply laminate and the cross-ply laminate subjected to the four aforementioned modes of deformation.
Numerical Study of Forward and Backward Whirling of Drill-String
Authors: Kapitaniak Marcin , Vaziri Vahid , Páez Chávez Joseph , Wiercigroch Marian
Published: July 2017

This work presents a numerical investigation of the undesired lateral vibrations (whirling) occurring in drill-strings, which is one of the main sources of losses in drilling applications. The numerical studies are conducted using a nonsmooth lumped parameter model, which has been calibrated based on a realistic experimental drilling rig. The numerical investigations are focused on identifying different types of whirling responses, including periodic and chaotic behavior, which have been previously observed experimentally. As a result, the parameter space is divided into different regions showing dynamically relevant responses of the model, with special interest on the influence of the mass and angular velocity of the drill-string system. In particular, the study reveals the coexistence of various types of whirling motion for a given set of parameters and their sensitivity to initial conditions. The obtained theoretical predictions confirm previous experimental studies carried out by the authors, which provides a solid basis for a better understanding of whirling phenomena in drill-string applications.
Low-Order Modeling of Combustion Noise in an Aero-Engine: The Effect of Entropy Dispersion
Authors: Mahmoudi Yasser , Giusti Andrea , Mastorakos Epaminondas , Dowling Ann P.
Published: July 2017

The present work studies the effect of entropy dispersion on the level of combustion noise at the turbine outlet of the Rolls-Royce ANTLE aero-engine. A new model for the decay of entropy waves, based on modeling dispersion effects, is developed and utilized in a low-order network model of the combustor (i.e., LOTAN code that solves the unsteady Euler equations). The proposed model for the dispersion of entropy waves only requires the mean velocity field as an input, obtained by Reynolds-averaged Navier–Stokes (RANS) computations of the demonstrator combustor. LOTAN is then coupled with a low-order model code (LINEARB) based on the semi-actuator disk model that studies propagation of combustion noise through turbine blades. Thus, by combining LOTAN and LINERAB, the combustion noise and its counterparts, direct and indirect noise, generated at the turbine exit are predicted. In comparison with experimental data, it is found that without the inclusion of entropy dispersion, the level of combustion noise at the turbine exit is overpredicted by almost 2 orders of magnitude. The introduction of entropy dispersion in LOTAN results in a much better agreement with the experimental data, highlighting the importance of entropy wave dispersion for the prediction of combustion noise in real engines. In more detail, the agreement with the experiment for high and low frequencies was very good. At intermediate frequencies, the experimental measurements are still overpredicted; however, the predicted noise is much smaller compared to the case without entropy dispersion. This discrepancy is attributed to (i) the role of turbulent mixing in the overall decay of the entropy fluctuations inside the combustor, not considered in the model developed for the decay of entropy waves, and (ii) the absence of a proper model in LINEARB for the decay of entropy waves as they pass through the turbine blade rows. These are areas that still need further development to improve the prediction of low-order network codes.
Process Analysis of Selective Exhaust Gas Recirculation for CO2 Capture in Natural Gas Combined Cycle Power Plants Using Amines
Authors: Elena Diego Maria , Bellas Jean-Michel , Pourkashanian Mohamed
Published: July 2017

Postcombustion CO2 capture from natural gas combined cycle (NGCC) power plants is challenging due to the large flow of flue gas with low CO2 content (∼3–4 vol %) that needs to be processed in the capture stage. A number of alternatives have been proposed to solve this issue and reduce the costs of the associated CO2 capture plant. This work focuses on the selective exhaust gas recirculation (S-EGR) configuration, which uses a membrane to selectively recirculate CO2 back to the inlet of the compressor of the turbine, thereby greatly increasing the CO2 content of the flue gas sent to the capture system. For this purpose, a parallel S-EGR NGCC system (53% S-EGR ratio) coupled to an amine capture plant (ACP) using monoethanolamine (MEA) 30 wt % was simulated using gCCS (gPROMS). It was benchmarked against an unabated NGCC system, a conventional NGCC coupled with an ACP (NGCC + carbon capture and storage (CCS)), and an EGR NGCC power plant (39% EGR ratio) using amine scrubbing as the downstream capture technology. The results obtained indicate that the net power efficiency of the parallel S-EGR system can be up to 49.3% depending on the specific consumption of the auxiliary S-EGR systems, compared to the 49.0% and 49.8% values obtained for the NGCC + CCS and EGR systems, respectively. A preliminary economic study was also carried out to quantify the potential of the parallel S-EGR configuration. This high-level analysis shows that the cost of electricity (COE) for the parallel S-EGR system varies from 82.1 to 90.0 $/MWhe for the scenarios considered, with the cost of CO2 avoided (COA) being in the range of 79.7–105.1 $/ton CO2. The results obtained indicate that there are potential advantages of the parallel S-EGR system in comparison to the NGCC + CCS configuration in some scenarios. However, further benefits with respect to the EGR configuration will depend on future advancements and cost reductions achieved on membrane-based systems.
Corrosion Behaviour of Bare and NiCrAlY Coated Alloy 214 in Supercritical Water at 700 °C
Authors: Bsat Suzan , Huang Xiao , Penttila Sami
Published: July 2017

Concerns with greenhouse gas emissions and the uncertainty of long-term supply of fossil fuels have resulted in renewed interest in nuclear energy as an essential part of the energy mix for the future. Many countries worldwide including Canada, China, and EU are currently undertaking the design of generation IV supercritical water-cooled reactor (SCWR) with higher thermodynamic efficiency and considerable plant simplification. The identification of appropriate materials for in-core and out-of-core components to contain the supercritical water (SCW) coolant is one of the major challenges for the design of SCWR. This study is carried out to evaluate the oxidation/corrosion behaviors of bare alloy 214 and NiCrAlY coated 214 under SCW at a temperature of 700 °C/25 MPa for 1000 h. The results show that chromium and nickel based oxide forms on the bare surface after exposure in SCW for 1000 h. A dense and adhered oxide layer, consisting of Cr2O3 with spinel (Ni(Cr, Al)2O4), was observed on NiCrAlY surface after 1000 h in SCW.
Time-Response of Recent Prefilming Airblast Atomization Models in an Oscillating Air Flow Field
Authors: Chaussonnet G. , Müller A. , Holz S. , Koch R. , Bauer H.-J.
Published: July 2017

The present study investigates the response of recent primary breakup models in the presence of an oscillating air flow and compares them to an experiment realized by Müller (2015, “Experimentelle Untersuchung des Zerstäubungsverhaltens Luftgestützter Brennstoffdüsen bei Oszillierenden Strömungen,” Ph.D. thesis, Karlsruhe Institute of Technology, Karlsruhe, Germany). The experiment showed that the oscillating flow field has a significant influence on the Sauter mean diameter (SMD) up to a given frequency. This observation highlights the low-pass filter character of the prefilming airblast atomization phenomenon, which also introduces a significant phase shift on the dynamics of SMD of the generated spray. The models are tested in their original formulations without any calibration in order to assess their robustness versus different experiments in terms of SMD and time-response to an oscillating flow field. Special emphasis is put to identify the advantages and weaknesses of theses models, in order to facilitate their future implementation in computational fluid dynamics (CFD) codes. It is observed that some models need an additional calibration of the time constant in order to match the time shift observed in the experiment, whereas some others show a good agreement with the experiment without any modification. Finally, it is demonstrated that the low-pass filter character of the breakup phenomenon can be retrieved by considering the history of the local gas velocity, instead of the instantaneous velocity. This might result in a higher simulation fidelity within CFD codes.
An Information Fusion Model Based on Dempster–Shafer Evidence Theory for Equipment Diagnosis
Authors: Zhou Dengji , Wei Tingting , Zhang Huisheng , Ma Shixi , Wei Fang
Published: July 2017

An abnormal operating effect can be caused by different faults, and a fault can cause different abnormal effects. An information fusion model, with hybrid-type fusion frame, is built in this paper, so as to solve this problem. This model consists of data layer, feature layer and decision layer, based on an improved Dempster–Shafer (D-S) evidence algorithm. After the data preprocessing based on event reasoning in data layer and feature layer, the information will be fused based on the new algorithm in decision layer. Application of this information fusion model in fault diagnosis is beneficial in two aspects, diagnostic applicability and diagnostic accuracy. Additionally, this model can overcome the uncertainty of information and equipment to increase diagnostic accuracy. Two case studies are implemented by this information fusion model to evaluate it. In the first case, fault probabilities calculated by different methods are adopted as inputs to diagnose a fault, which is quite different to be detected based on the information from a single analytical system. The second case is about sensor fault diagnosis. Fault signals are planted into the measured parameters for the diagnostic system, to test the ability to consider the uncertainty of measured parameters. The case study result shows that the model can identify the fault more effectively and accurately. Meanwhile, it has good expansibility, which may be used in more fields.
Determination of Energy Release Rate Through Sequential Crack Extension
Authors: McCann Scott , Ostrowicki Gregory T. , Tran Anh , Huang Timothy , Bernhard Tobias , Tummala Rao R. , Sitaraman Suresh K.
Published: July 2017

A method to determine the critical energy release rate of a peel tested sample using an energy-based approach within a finite element framework is developed. The method uses a single finite element model, in which the external work, elastic strain energy, and inelastic strain energy are calculated as nodes along the crack interface are sequentially decoupled. The energy release rate is calculated from the conservation of energy. By using a direct, energy-based approach, the method can account for large plastic strains and unloading, both of which are common in peel tests. The energy rates are found to be mesh dependent; mesh and convergence strategies are developed to determine the critical energy release rate. An example of the model is given in which the critical energy release rate of a 10-μm thick electroplated copper thin film bonded to a borosilicate glass substrate which exhibited a 3.0 N/cm average peel force was determined to be 20.9 J/m2.
Revisiting the growth mechanism of atomic layer deposition of Al2O3: A vibrational sum-frequency generation study
Authors: Vandalon Vincent , Kessels W. M. M. (Erwin)
Published: July 2017

The growth mechanism of the prototypical atomic layer deposition (ALD) process of Al2O3 using Al(CH3)3 (TMA) and H2O has been revisited on the basis of insights obtained with the nonlinear optical analysis technique of broadband sum-frequency generation (BB-SFG). With BB-SFG spectroscopy, both the –CH3 and –OH surface groups ruling the growth of Al2O3 by ALD were detected and could be monitored during the ALD process with submonolayer sensitivity. Several remaining questions pertaining to the growth mechanism of Al2O3 were addressed. The reaction kinetics of the H2O half-cycle were studied for ALD between 100 and 300 °C, and the reaction cross section σ was determined. The cross section at 300 °C was fairly large (σ = 3 × 10−19 cm2) and it decreased with decreasing temperature. Below 200 °C, the cross section also clearly varied with the surface coverage. For example, at 100 °C, the cross section started at σ = 1 × 10−20 cm2 for a full –CH3 coverage and decreased to σ = 3 × 10−21 cm2 for a 60% coverage. This coverage dependence of the reaction kinetics also explains the presence of the persistent –CH3 groups at low temperatures which are no longer reactive toward H2O. By a dedicated study using x-ray photo-emission spectroscopy, it was demonstrated that the persistent –CH3 groups were not incorporated into the film as a contaminant species. The absolute –CH3 coverage was measured for ALD between 100 and 450 °C. With this data, steric hindrance was ruled out as the cause of the self-limiting behavior in the TMA half-cycle on basis of the decrease observed in the –CH3 coverage with temperature. The self-limiting behavior was attributed to the depletion of under coordinated O during the TMA half-cycle. Moreover, the chemisorption of TMA on the -OH surface groups during the TMA half-cycle was investigated. On average, 1.5 –CH3 ligands remained on the surface per deposited Al atom after the TMA half-cycle at 300 °C, and this number decreased to 0.8 at 100 °C. These insights into the underlying growth mechanism augment the understanding of Al2O3 ALD and reveal several nuances in this well-studied ALD process.
Ag+ reduction and silver nanoparticle synthesis at the plasma–liquid interface by an RF driven atmospheric pressure plasma jet: Mechanisms and the effect of surfactant
Authors: Kondeti V. S. Santosh K. , Gangal Urvashi , Yatom Shurik , Bruggeman Peter J.
Published: July 2017

The involvement of plasma produced species in the reduction of silver ions at the plasma–liquid interface is investigated using a well-characterized radio-frequency driven atmospheric pressure plasma jet. The absolute gas phase H density was measured using two photon absorption laser induced fluorescence in the free jet. Broadband absorption and transmission electron microscopy were used to study the synthesis of silver nanoparticles (AgNPs). It is shown that fructose, an often used surfactant/stabilizer for AgNP synthesis, also acts as a reducing agent after plasma exposure. Nonetheless, surfactant free AgNP synthesis is observed. Several experimental findings indicate that H plays an important role in the reduction of silver ions for the plasma conditions in this study. Vacuum ultraviolet photons generated by the plasma are able to reduce silver ions in the presence of fructose. Adding H2 to the argon feed gas leads to the production of a large amount of AgNPs having a particle size distribution with a maximum at a diameter of 2–3 nm, which is not observed for argon plasmas. This finding is consistent with a smaller concentration of reducing species at the plasma–liquid interface for Ar with the H2 admixture plasma. The smaller flux of reactive species to the liquid is in this case due to a less strong interaction of the plasma with the liquid. The formation of the nanoparticles was observed even at a distance of 6–7 mm below the tip of the plasma plume, conditions not favoring the injection of electrons.
Effect of the static compressive load on vibration propagation in multistory buildings and resulting heavyweight floor impact sounds
Authors: Kwak Yunsang , Lee Sinyeob , Park Jeongwon , Hwang Dukyoung , Jeon Jin Yong , Park Junhong
Published: July 2017

Experiments were performed to identify the mechanism of heavyweight floor impact sound transmission through floors in a high-rise apartment building. Vibration and sound levels on each floor of the multistory building were measured. The vibration generated at a given floor was transferred to multiple adjacent floors with decreasing amplitudes proportional to the distance from the excited floor. This vibration transfer introduced significant sound transmissions. The structural static load varied depending on the floor location due to differences in the weight of the structure above the floor, especially for wall construction buildings. The static load at the wall of the bottom floor was the largest among the different floors. The influence of this static load on the impact sound generation was investigated through tests in the actual building and the scale model, respectively. The results were numerically analyzed using the spectral element method. With the increasing static load, the resonance frequencies of the floor increased due to the change in the vibration modes of the structure. The modulated sound generation from the floor vibrations transmitted to multiple layers with larger magnitudes due to this static load.