Numerical modeling of a hot-wire anemometer in turbulent flows

The present thesis deals with the numerical modeling of an hot wire anemometer inside a turbulent channel flow at Re_tau=180 with heat transfer. There are two main approaches when studying turbulence: one could follow an experimental path or a numerical approach could be pursued. Experiments showed some issues when measuring turbulence with hot wire anemometry, spatial and temporal filtering are two examples of such problems. In the present work, numerical simulations were performed in order to validate a code that model a hot-wire probe inside a turbulent channel flow. Direct Numerical Simulation (DNS) solved through a spectral code were used to build such model, due to their high level of precision and resolution. A validation process was performed starting from Kim & Moin experience and Kasagi studies related to DNS of channel flow with passive scalar. Following this path we implement inside our code a line source of heat mimicking the hot-wire behaviour. While simulations were running we collected statistics in order to know the values regarding turbulence fluctuations throughout the entire channel. We obtained a new data-set coming from DNS and spectral element method with not only just a passive scalar but a precise implementation of an hot-wire probe

Plato on time as a cosmic phenomenon

The thesis presents an original interpretation of the account of time in the Timaeus (37c6-39e2), arguing that time in Plato is best conceived of as a cosmic phenomenon. In Part I, my view is contrasted in crucial respects with the consensus reading, that focuses on the metaphysical definition (time is a moving image of eternity, 37d5) and downplays the importance of the cosmos and the planets in the creation of time. I reject the standard reading of αἰών as ‘eternity’ and take it instead as a feature that is essential to the model qua living being. It follows that the creation of time – being the image of αἰών – is essential to the cosmic living being. Time, however, is best defined as a cosmic phenomenon, because it is constituted by the living motion of the cosmos and identified with the visible revolutions of the planets. In the continuation of the thesis, I examine two essential aspects of Plato’s account that need further enquiry – life and structure. In Part II I focus on the semantic history of αἰών and argue that in Plato, αἰών acquires a paradigmatic function in relation to time, while still retaining the core of its traditional meaning as ‘lifespan’. In fact, αἰών and time are both defined by Plato as totalities of life, although αἰών consists in an undivided unity, whereas time is structured in sequences of parts composing a whole. In Part III I focus on how the planets make the periods of the cosmic soul visible and, as a consequence, display the enumerable structure of time. That structure consists in fact in the visible patterns of changing configurations the planets display. In doing so, they mark out sequences of units, whose optimality makes time the best instantiation of number in the physical world

Pottery production at the mesolithic site of Kabbashi Haitah (central Sudan) : an integrated morphological, petrographic and mineralogical analysis

This paper presents the results of an interdisciplinary archeometric study on Early Mesolithic pottery from the prehistoric site of Kabbashi Haitah, located 35 km north of Khartoum (central Sudan), along the Nile Valley. A large set of potsherds, selected after a preliminary macroscopic analysis of 1075 fragments representing the various vessels (mainly plain and globular in shape, with various rim diameter), macrofabrics and decoration types (either with or without incised or stamped decorations, i.e. incisedwavy line and rocker stamp) was analysed to define the type of the raw materials used and their manufacturing technology. The mineralogical and petrographic features, determined by optical microscopy and X-ray powder diffraction, indicate that the pottery was produced using an illitic clay tempered with quartz and/or K-feldspar derived from granite/syenite grinding, and fired in the temperature range between 750 and 900 degrees C

Fluorescent Carbon Dots from Food Industry By-Products for Cell Imaging

Herein, following a circular economy approach, we present the synthesis of luminescent carbon dots via the thermal treatment of chestnut and peanut shells, which are abundant carbon-rich food industry by-products. As-synthesized carbon dots have excellent water dispersibility thanks to their negative surface groups, good luminescence, and photo-stability. The excitation-emission behaviour as well as the surface functionalization of these carbon dots can be tuned by changing the carbon source (chestnuts or peanuts) and the dispersing medium (water or ammonium hydroxide solution). Preliminary in vitro biological data proved that the samples are not cytotoxic to fibroblasts and can act as luminescent probes for cellular imaging. In addition, these carbon dots have a pH-dependent luminescence and may, therefore, serve as cellular pH sensors. This work paves the way towards the development of more sustainable carbon dot production for biomedical applications

Proteomic Profiling Reveals Specific Molecular Hallmarks of the Pig Claustrum

The present study, employing a comparative proteomic approach, analyzes the protein profile of pig claustrum (CLA), putamen (PU), and insula (IN). Pig brain is an interesting model whose key translational features are its similarities with cortical and subcortical structures of human brain. A greater difference in protein spot expression was observed in CLA vs PU as compared to CLA vs IN. The deregulated proteins identified in CLA resulted to be deeply implicated in neurodegenerative (i.e., sirtuin 2, protein disulfide-isomerase 3, transketolase) and psychiatric (i.e., copine 3 and myelin basic protein) disorders in humans. Metascape analysis of differentially expressed proteins in CLA vs PU comparison suggested activation of the α-synuclein pathway and L1 recycling pathway corroborating the involvement of these anatomical structures in neurodegenerative diseases. The expression of calcium/calmodulin-dependent protein kinase and dihydropyrimidinase like 2, which are linked to these pathways, was validated using western blot analysis. Moreover, the protein data set of CLA vs PU comparison was analyzed by Ingenuity Pathways Analysis to obtain a prediction of most significant canonical pathways, upstream regulators, human diseases, and biological functions. Interestingly, inhibition of presenilin 1 (PSEN1) upstream regulator and activation of endocannabinoid neuronal synapse pathway were observed. In conclusion, this is the first study presenting an extensive proteomic analysis of pig CLA in comparison with adjacent areas, IN and PUT. These results reinforce the common origin of CLA and IN and suggest an interesting involvement of CLA in endocannabinoid circuitry, neurodegenerative, and psychiatric disorders in humans

Risk stratification of patients with SARS-CoV-2 by tissue factor expression in circulating extracellular vesicles

Inflammatory response following SARS-CoV-2 infection results in substantial increase of amounts of intravascular pro-coagulant extracellular vesicles (EVs) expressing tissue factor (CD142) on their surface. CD142-EV turned out to be useful as diagnostic biomarker in COVID-19 patients. Here we aimed at studying the prognostic capacity of CD142-EV in SARS-CoV-2 infection. Expression of CD142-EV was evaluated in 261 subjects admitted to hospital for pneumonia and with a positive molecular test for SARS-CoV-2. The study population consisted of a discovery cohort of selected patients (n = 60) and an independent validation cohort including unselected consecutive enrolled patients (n = 201). CD142-EV levels were correlated with post-hospitalization course of the disease and compared to the clinically available 4C Mortality Score as referral. CD142-EV showed a reliable performance to predict patient prognosis in the discovery cohort (AUC = 0.906) with an accuracy of 81.7%, that was confirmed in the validation cohort (AUC = 0.736). Kaplan-Meier curves highlighted a high discrimination power in unselected subjects with CD142-EV being able to stratify the majority of patients according to their prognosis. We obtained a comparable accuracy, being not inferior in terms of prediction of patients' prognosis and risk of mortality, with 4C Mortality Score. The expression of surface vesicular CD142 and its reliability as prognostic marker was technically validated using different immunocapture strategies and assays. The detection of CD142 on EV surface gains considerable interest as risk stratification tool to support clinical decision making in COVID-19

E-ELT M4 adaptive unit final design and construction: a progress report

The E-ELT M4 adaptive unit is a fundamental part of the E-ELT: it provides the facility level adaptive optics correction that compensates the wavefront distortion induced by atmospheric turbulence and partially corrects the structural deformations caused by wind. The unit is based on the contactless, voice-coil technology already successfully deployed on several large adaptive mirrors, like the LBT, Magellan and VLT adaptive secondary mirrors. It features a 2.4m diameter flat mirror, controlled by 5316 actuators and divided in six segments. The reference structure is monolithic and the cophasing between the segments is guaranteed by the contactless embedded metrology. The mirror correction commands are usually transferred as modal amplitudes, that are checked by the M4 controller through a smart real-time algorithm that is capable to handle saturation effects. A large hexapod provides the fine positioning of the unit, while a rotational mechanism allows switching between the two Nasmyth foci. The unit has entered the final design and construction phase in July 2015, after an advanced preliminary design. The final design review is planned for fall 2017; thereafter, the unit will enter the construction and test phase. Acceptance in Europe after full optical calibration is planned for 2022, while the delivery to Cerro Armazones will occur in 2023. Even if the fundamental concept has remained unchanged with respect to the other contactless large deformable mirrors, the specific requirements of the E-ELT unit posed new design challenges that required very peculiar solutions. Therefore, a significant part of the design phase has been focused on the validation of the new aspects, based on analysis, numerical simulations and experimental tests. Several experimental tests have been executed on the Demonstration Prototype, which is the 222 actuators prototype developed in the frame of the advanced preliminary design. We present the main project phases, the current design status and the most relevant results achieved by the validation tests

Supplement: "Localization and broadband follow-up of the gravitational-wave transient GW150914" (2016, ApJL, 826, L13)

This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands