Blade scale effects of tip leakage

October 1990Includes bibliographical references (leaves 43-44)The effects of blade-tip leakage in a turbine are investigated by modeling the stage as an incomplete actuator disk. It is found that the spanwise flow redistribution due to the gap is such as to produce a uniform unloading of the blades, despite the very concentrated leakage. Partial lift retention at the blade tip is accounted for based on a leakage jet-free stream collision model which successfully predicts the roll-up of the leakage flow. The predicted efficiency loss due to the gap correlates well with experimental data

Coulomb displacement energies, energy differenced and neutron skins

A Fock space representation of the monopole part of the Coulomb potential is presented. Quantum effects show through a small orbital term in $l(l+1)$. Once it is averaged out, the classical electrostatic energy emerges as an essentially exact expression, which makes it possible to eliminate the Nolen-Schiffer anomaly, and to estimate neutron skins and the evolution of radii along yrast states of mirror nuclei. The energy differences of the latter are quantitatively reproduced by the monopole term and a schematic multipole one.Comment: 4 pages, 3 figures, Revte

Machine Learning in Fetal Cardiology: What to Expect

In fetal cardiology, imaging (especially echocardiography) has demonstrated to help in the diagnosis and monitoring of fetuses with a compromised cardiovascular system potentially associated with several fetal conditions. Different ultrasound approaches are currently used to evaluate fetal cardiac structure and function, including conventional 2-D imaging and M-mode and tissue Doppler imaging among others. However, assessment of the fetal heart is still challenging mainly due to involuntary movements of the fetus, the small size of the heart, and the lack of expertise in fetal echocardiography of some sonographers. Therefore, the use of new technologies to improve the primary acquired images, to help extract measurements, or to aid in the diagnosis of cardiac abnormalities is of great importance for optimal assessment of the fetal heart. Machine leaning (ML) is a computer science discipline focused on teaching a computer to perform tasks with specific goals without explicitly programming the rules on how to perform this task. In this review we provide a brief overview on the potential of ML techniques to improve the evaluation of fetal cardiac function by optimizing image acquisition and quantification/segmentation, as well as aid in improving the prenatal diagnoses of fetal cardiac remodeling and abnormalities

Macropore Formation and Pore Morphology Characterization of Heavily Doped p-Type Porous Silicon

Tuning the pore diameter of porous silicon films is essential for some applications such as biosensing, where the pore size can be used for filtering analytes or to control the biofunctionalization of its walls. However, macropore (>50nm) formation on p-type silicon is not yet fully controlled due to its strong dependence on resistivity. Electrochemical etching of heavily doped p-type silicon usually forms micropores (<5nm), but it has been found that bigger sizes can be achieved by adding an organic solvent to the electrolyte. In this work, we compare the results obtained when adding dimethylformamide (DMF) and dimethylsulfoxide (DMSO) to the electrolyte as well as the effect of a post-treatment of the sample with potasium hydroxide (KOH) and sodium hydroxide (NaOH) for macropore formation in p-type silicon with resistivities between 0.001 and 10Ω·cm, achieving pore sizes from 5 to 100nm

048— Sibling Relationship Quality in Emerging Adulthood: A Phenomenological Study of Latinx College Students

This phenomenological research examined Latinx college students’ sibling relationships in emerging adulthood. Researchers developed and employed a coding schema based on the work of Buhrmester and Furman (1987) to code for relationship quality. A thematic analysis revealed differences in relationship quality based on participants’ culture identity

Observational constraints to boxy/peanut bulge formation time

Boxy/peanut bulges are considered to be part of the same stellar structure as bars and both could be linked through the buckling instability. The Milky Way is our closest example. The goal of this letter is determining if the mass assembly of the different components leaves an imprint in their stellar populations allowing to estimate the time of bar formation and its evolution. To this aim we use integral field spectroscopy to derive the stellar age distributions, SADs, along the bar and disc of NGC 6032. The analysis shows clearly different SADs for the different bar areas. There is an underlying old (>=12 Gyr) stellar population for the whole galaxy. The bulge shows star formation happening at all times. The inner bar structure shows stars of ages older than 6 Gyrs with a deficit of younger populations. The outer bar region presents a SAD similar to that of the disc. To interpret our results, we use a generic numerical simulation of a barred galaxy. Thus, we constrain, for the first time, the epoch of bar formation, the buckling instability period and the posterior growth from disc material. We establish that the bar of NGC 6032 is old, formed around 10 Gyr ago while the buckling phase possibly happened around 8 Gyr ago. All these results point towards bars being long-lasting even in the presence of gas.Comment: Accepted for publication in MNRAS Letter

Levels and patterns of objectively assessed physical activity and compliance with different public health guidelines in university students

ArticleBackground Physical activity (PA) is associated with health enhancement. The aim of this study was to assess: 1) levels and patterns of PA in university students by using accelerometers; and 2) the percentage of fulfilment of PA recommendations for adults, according to different public health guidelines. Methods Observational cross-sectional study (Cuenca’s Adults Study) involving 296 (206 women) healthy Spanish university students aged 18–25 years old. Participants wore the ActiGraph GT1M accelerometer for seven consecutive days. Total PA, steps and time spent in sedentary time, light, moderate, vigorous, and moderate to vigorous PA (MVPA) was assessed, and the prevalence of sufficient PA was calculated according to various public health guidelines. Results No sex differences in total PA were found. University students were more sedentary during weekend days than weekdays (p<0.05). Only 30.3% of participants accumulated 30 min/day at least five days a week of MVPA. A total of 5.4% of students met the recommendation of 150 min/week of MVPA or 75 min/week of vigorous PA, in PA bouts of at least 10 min. using the same definition, but on five or more days a week, only 0.5% students were found to meet the recommendation. In addition, only 0.5% of students met the recommendation of 30 min/day of MVPA, at least five days a week and in bouts of at least 10 min. Finally, 28.1% of the students met the recommendation of 10,000 steps/day. Conclusions Our study shows a high incidence of sedentary time in university students. The number of students meeting PA recommendations significantly differed depending on the recommendation proposed. Specific strategies to promote PA in this population are necessary as well as an agreement as to which PA guidelines should be used.Fundación para la Investigación SanitariaMinistry of Health and Consumer AffairsInstituto de Salud Carlos IIIRed de Investigación en Actividades Preventivas y de Promoción de Salu

Human case of swine influenza A (H1N1), Aragon, Spain, November 2008

A human case of swine influenza A (H1N1) in a 50-year-old woman from a village near Teruel (Aragon, in the north-east of Spain), with a population of about 200 inhabitants, has been reported in November 2008.S

On the Effect of Correlation on the Capacity of Backscatter Communication Systems

We analyse the effect of correlation between the forward and backward links on the capacity of backscatter communication systems. To that aim, we obtain an analytical expression for the average capacity under a correlated Rayleigh product fading channel, as well as closed-form asymptotic expressions for the high and low signal-to-noise ratio (SNR) regimes. Our results show that correlation is indeed detrimental for a fixed target SNR; contrarily to the common belief, we also see that correlation can be actually beneficial in some instances when a fixed power budget is considered.Comment: This work has been submitted for publication. Copyright may be transferred without notice, after which this version may no longer be accessibl