Validation of the transient liquid crystal thermography technique for heat transfer measurements on a rotating cooling passage

The transient liquid crystal thermography can be a suitable tool to study heat\u2010transfer performances on internal cooling schemes of gas turbine blades. One of the hot topics related to this methodology is about the level of reliability of the heat\u2010transfer assessments in rotating tests where the fluid experiences time\u2010dependent rotating effects. The present study contribution aims to experimentally validate by cross\u2010comparison of the outcomes obtained by employing the transient technique with those from the steady\u2010state liquid crystal thermography in which the rotational effects occur as time\u2010stable by definition. Heat\u2010transfer measurements have been conducted on a rib\u2010roughened square cross\u2010section channel, with an inlet Reynolds number equal to 20,000 and rotation number up to 0.2. Special attention has been paid to the definition of the more reliable calibration strategy for liquid crystals that are employed in the transient thermography and to the proper estimation of the heat losses in the post\u2010processing of the steady\u2010state experimental data. The results show great accordance between the indications provided by the two techniques both in static and rotating conditions, demonstrating the possibility to exploit the advantages of the transient liquid crystal thermography for the investigation of heat transfer into rotating cooling channels

A Statistical Prescription to Estimate Properly Normalized Distributions of Different Particle Species

We describe a statistical method to avoid biased estimation of the content of different particle species. We consider the case when the particle identification information strongly depends on some kinematical variables, whose distributions are unknown and different for each particles species. We show that the proposed procedure provides properly normalized and completely data-driven estimation of the unknown distributions without any a priori assumption on their functional form. Moreover, we demonstrate that the method can be generalized to any kinematical distribution of the particles

Effects of different cross-sections of Body Centered Cubic cells on pressure drop and heat transfer of additively manufactured heat sinks

In many industrial applications, heat loads management requires the design and production of compact heat exchangers which are expected to handle high thermal loads with acceptable pressure losses, while assuring good mechanical performances. These challenging targets can be achieved by filling the cavities where the cool/hot fluid circulates with lattice structures promoting the heat exchange between the fluid and the cavity boundaries. Such lattice structures can be only produced through Additive Manufacturing due to their high geometric complexity. Recent experimental investigations proved the effectiveness of some kinds of lattice structures having a circular cross section. Here the aerothermal behaviour of Body-Centred Cubic (BCC) lattice stagger arrays in a rectangular channel was experimentally investigated by considerably extending the previous studies to higher Reynolds numbers (up to 30′000) and to new types of lattice structures. Specifically, three new BCC structures having a cam-like, drop-like and elliptical cross section were explored in this work and compared against those having circular cross section. All the samples were manufactured by means of Laser Powder Bed Fusion and made from AlSi10Mg. At first, the heat exchangers were comprehensively characterized by means of optical non-destructive methods. Successively they were tested in a dedicated rig by imposing constant heat flux boundary conditions. The characteristics of the transitional or fully turbulent approaching flow to the test section are also reported thanks to dedicated flow field measurements performed by Particle Image Velocimetry. According to the obtained results, the BCC structure with the circular cross section of larger diameter is the most effective in terms of heat transfer, although it is largely penalized by the pressure losses. Similar heat transfer performances were achieved by the tapered cross section of elliptical shape with the advantage of a considerably lower friction factor. Pressure losses resulted almost identical for all the tapered cross sections but lower than those of the circular one having an equal frontal dimension. When considering the thermal performance factor the circular shape becomes unfavourable for Re>20′000, while the elliptical cross section is the best choice to efficiently promote heat transfer up to Re=30′000

Acquisition and integration of differential pressure measurements on sails for boat performances improvement

In this paper, we integrated within a specifically developed acquisition system, denoted as Oceanus, the measurements from a differential pressure sensor between the two sides of a sail (windward and leeward sides); experiments have been performed using a light jib sail of a 35 feet cruising-racing yacht. We analyzed the correlation between such a signal and other standard signals usually present on board such as boat speed, intensity and direction of apparent or real wind; moreover, data from Inertial Measurement Units are handled. We also considered the Target Data, which depend on the actual point of sail, and the discrepancy between measured data and the predicted Targets is monitored as an error in terms of the true wind angle and boat velocity. In this way, the trimmer/helmsman can monitor the differential sail pressure together with Target data and decide to reduce the error with a correction in how sails are trimmed, rather than in how the boat is steered to achieve an improvement of boat performances. The resulting telemetry system represents an effective low cost solution, which is affordable even for amateur yachtsmen

Level-3 Calorimetric Resolution available for the Level-1 and Level-2 CDF Triggers

As the Tevatron luminosity increases sophisticated selections are required to be efficient in selecting rare events among a very huge background. To cope with this problem, CDF has pushed the offline calorimeter algorithm reconstruction resolution up to Level 2 and, when possible, even up to Level 1, increasing efficiency and, at the same time, keeping under control the rates. The CDF Run II Level 2 calorimeter trigger is implemented in hardware and is based on a simple algorithm that was used in Run I. This system has worked well for Run II at low luminosity. As the Tevatron instantaneous luminosity increases, the limitation due to this simple algorithm starts to become clear: some of the most important jet and MET (Missing ET) related triggers have large growth terms in cross section at higher luminosity. In this paper, we present an upgrade of the Level 2 Calorimeter system which makes the calorimeter trigger tower information available directly to a CPU allowing more sophisticated algorithms to be implemented in software. Both Level 2 jets and MET can be made nearly equivalent to offline quality, thus significantly improving the performance and flexibility of the jet and MET related triggers. However in order to fully take advantage of the new L2 triggering capabilities having at Level 1 the same L2 MET resolution is necessary. The new Level-1 MET resolution is calculated by dedicated hardware. This paper describes the design, the hardware and software implementation and the performance of the upgraded calorimeter trigger system both at Level 2 and Level 1.Comment: 5 pages, 5 figures,34th International Conference on High Energy Physics, Philadelphia, 200

Polyphenols rich diets and risk of type 2 diabetes

Type 2 diabetes is an increasing health concern worldwide. Both genetic and environmental risk factors as improper dietary habits or physical inactivity are known to be crucial in the pathogen-esis of type 2 diabetes. Polyphenols are a group of plant-derived compounds with anti-inflammatory and antioxidant properties that are associated with a low prevalence of metabolic conditions charac-terized by insulin resistance, including obesity, diabetes, and hypertension. Moreover, there is now full awareness that foods that are rich in phytochemicals and polyphenols could play an important role in preserving human cardiovascular health and substantial clinical evidence indicates that regu-lar dietary consumption of such foods affects favorably carbohydrate metabolism. This review briefly summarizes the evidence relating dietary patterns rich in polyphenols with glucose metabolism and highlights the potential benefits of these compounds in the prevention of type 2 diabetes

Ruling out coronavirus disease 2019 in patients with pneumonia: The role of blood cell count and lung ultrasound

Coronavirus disease 2019 (COVID-19) is characterized by a distinctive blood leucocyte pattern and B-lines on lung ultrasound (LUS) as marker of alveolar-interstitial syndrome. We aimed to evaluate the accuracy of blood leucocyte count alone or in combination with LUS for COVID-19 diagnosis. We retrospectively enrolled consecutive patients diagnosed with community acquired pneumonia (CAP) at hospital admission to derive and validate cutoff values for blood cell count that could be predictive of COVID-19 before confirmation by the nucleic acid amplification test (NAAT). Cutoff values, generated and confirmed in inception (41/115, positive/negative patients) and validation (100/180, positive/negative patients) cohorts, were ≤17 and ≤10 cells/mm3 for basophils and eosinophils, respectively. Basophils and/or eosinophils below cutoff were associated with sensitivity of 98% (95%CI, 94–100) and negative likelihood ratio of 0.04 (95%CI, 0.01–0.11). In a subgroup of 265 subjects, the sensitivity of B-line on LUS was 15% lower (p < 0.001) than that of basophils and/or eosinophils below cutoff. The combination of B-lines with basophils and eosinophils below cutoff was associated with a moderate increase of the positive likelihood ratio: 5.0 (95%CI, 3.2–7.7). In conclusion, basophil and eosinophil counts above the generated cutoff virtually rule out COVID-19 in patients with CAP. Our findings can help optimize patient triage pending the NAAT results

Measuring the hadronic cross section via radiative return

Recently it has been demonstrated that particle factories, such as DAPHNE and PEP-II, operating at fixed center-of-mass energies, are able to measure hadronic cross sections as a function of the hadronic system energy using the raditive return. This paper is an experimental overview of the progress in this aera. Preliminary results from KLOE for the process e+e- -> \rho \gamma -> \pi+\pi-\gamma and a fit to the pion form factor are presented. Some first results from the BABAR collaboration are also shown.Comment: Invited talk presented at RADCOR/Loops and Legs 2002, Kloster Banz/Germany, September 8-13 2002, 6 pages, 2 Figures; v1: references added, typos correcte

Measurement of hadronic cross section and preliminary results on the pion form factor using the radiative return at DAPHNE

In the fixed energy environment of the $e^{+}e^{-}$ collider DA$\Phi$NE, KLOE can measure the cross section of the process $e^{+}e^{-} \to$ hadrons as a function of the hadronic system energy using the radiative return. At energies below 1 GeV, $e^{+}e^{-} \to \rho \to \pi^{+}\pi^{-}$ is the dominating hadronic process. We report here on the status of the analysis for the e^{+}e^{-} \to \ppg channel, which allows to obtain a preliminary measurement of the pion form factor using an integrated luminosity of $\sim73 pb^{-1}$.Comment: Invited talk at the Seventh International Workshop on Tau Lepton Physics (TAU02-WE07), Santa Cruz, Ca, USA, Sept 2002, 9 pages, LaTeX, 9 eps figure

Measurement of the branching fraction for the decay KS --> pi e nu

We present a measurement of the branching ratio BR(KS --> pi e nu) performed using the KLOE detector. KS mesons are produced in the reaction e+ e- --> phi --> KS KL at the DAFNE collider. In a sample of about 5 million KS-tagged events we find 624 +- 30 semileptonic KS decays. Normalizing to the KS --> pi+ pi- count in the same data sample, we obtain BR(KS --> pi e nu) = (6.91 +- 0.37) 10^-4, in agreement with the Standard Model expectation.Comment: 9 pages, 5 Encapsulated Postscript figures. Submitted to Phys. Lett.