Preliminary design and optimization of a subsonic turbine for rotating detonation engine applications

LAUREA MAGISTRALELo scopo di questo lavoro è la progettazione di una turbina subsonica con un flusso ad alto Mach in ingresso. Per migliorare l’efficienza delle turbine a gas, recenti ricerche hanno studiato la possibilità di adottare un Combustore a Detonazione Rotante (RDC), al posto del classico combustore. Si tratta di una tecnologia basata sulla combustione a detonazione e studi sul ciclo termodinamico hanno mostrato risultati ottimistici in termini di prestazioni, efficienza e riduzione delle emissioni inquinanti. Il flusso che esce dal combustore detonante è supersonico, non uniforme e instabile. Design efficienti di turbine supersoniche sono possibili, ma le perdite dovute agli shock sono sempre presenti. Per questo motivo abbiamo investigato un approccio alternativo per accoppiare RDC e turbina: creare un condotto di transizione che decelera il flusso rendendolo subsonico. A causa delle disuniformità e instabilità, la decelerazione fino a Mach convenzionali di 0.2÷0.3 produrrebbe tante perdite da vanificare i vantaggi della combustione a detonazione. La progettazione della turbina è partita da un’analisi parametrica alla linea media, per trovare il punto di massima efficienza. È stato utilizzato il software zTurbo per i calcoli alla linea media ed è stato creato un algoritmo specifico per l’analisi parametrica. A causa del flusso particolare, il caso analizzato è al di fuori del range di validità delle correlaioni delle perdite implementate in zTurbo, per cui abbiamo creato una strategia di estrapolazione per le perdite di Traupel. Questa funziona bene per le perdite di profilo, ma non funziona per quelle secondarie. Il passo successivo è stato la progettazione del profilo della pala e del canale meridionale tramite simulazioni CFD 2D. Per statore e rotore sono stati analizzati il numero di pale, la lunghezza della corda, lo spessore della pala e la forma della linea media e del canale meridionale per trovare la combinazione che produce meno perdite. Poi è stata eseguita un’ottimizzazione dei profili tramite il codice FORMA, per migliorare le prestazioni. I profili ottimizzati sono stati sviluppati in 3D per verificarne il comportamento, ottenendo risultati ottimisitici. Infine sono state eseguite due verifiche: meccanica e lavoro in condizioni off-design. Entrambe hanno restituito buoni risultati.The aim of this thesis is the design of a subsonic turbine with high inlet Mach number. To improve the efficiency of gas turbines, recently it was investigated the possibility to replace a classic combustor with a Rotating Detonation Combustor (RDC). This is a novel technology based on the detonation combustion mode and thermodynamic cycle studies have shown optimistic results in terms of performance, efficiency and emission of pollutants. The flow coming out from the detonative combustor is supersonic, non-uniform and unsteady. Efficient design of supersonic turbines is possible to deal with the outlet supersonic flow, but losses associated to shocks will always be present. For this reason, we investigated an alternative approach to couple an RDC with a gas turbine, adopting a transition duct that decelerate the flow to a subsonic condition. Due to the high non uniformities and unsteadiness of the flow, the deceleration to conventional turbine inlet Mach number of 0.2÷0.3 will produce a high amount of losses, cancelling the advantage of detonative combustion. The design of the turbine was approached starting from a mean-line parametric analysis, to find the point of maximum efficiency. The mean-line software zTurbo was used and a tailored algorithm was created to run the analysis. Due to the particular inlet flow, we were out of validity range of losses correlations implemented in zTurbo, so an extrapolation strategy for Traupel correlations was adopted. It works well for profile losses, but it is inadequate for secondary ones. The following step was the design of the blade profile and meridional channel geometry through 2D CFD simulations. For both stator and rotor we varied the solidity, chord length, blade thickness, camber line and meridional channel shapes to find the combination that produces the lowest amount of losses. Then, a shape optimization procedure using software FORMA was performed to improve turbine performances. The optimized shapes were developed in 3D to assess the 3D flow behavior, finding optimistic results. Finally, mechanical assessment and off-design working conditions analysis were performed, showing that the blades can withstand the static loadings and that performance reduction in off-design conditions are limited

Thick disk kinematics from RAVE and the solar motion

Radial velocity surveys such as the Radial Velocity Experiment (RAVE) provide us with measurements of hundreds of thousands of nearby stars most of which belong to the Galactic thin, thick disk or halo. Ideally, to study the Galactic disks (both thin and thick) one should make use of the multi-dimensional phase-space and the whole pattern of chemical abundances of their stellar populations. In this paper, with the aid of the RAVE Survey, we study the thin and thick disks of the Milky Way, focusing on the latter. We present a technique to disentangle the stellar content of the two disks based on the kinematics and other stellar parameters such as the surface gravity of the stars. Using the Padova Galaxy Model, we checked the ability of our method to correctly isolate the thick disk component from the Galaxy mixture of stellar populations. We introduce selection criteria in order to clean the observed radial velocities from the Galactic differential rotation and to take into account the partial sky coverage of RAVE. We developed a numerical technique to statistically disentangle thin and thick disks from their mixture. We deduce the components of the solar motion relative to the Local Standard of Rest (LSR) in the radial and vertical direction, the rotational lag of the thick disk component relative to the LSR, and the square root of the absolute value of the velocity dispersion tensor for the thick disk alone. The analysis of the thin disk is presented in another paper. We find good agreement with previous independent parameter determinations. In our analysis we used photometrically determined distances. In the Appendix we show that similar values can be found for the thick disk alone as derived in the main sections of our paper even without the knowledge of photometric distances.Comment: accepted on A&A, please see companion paper "THIN disk kinem...

Dietary Supplements for Intestinal Inflammation

Intestinal inflammation leads to various chronic diseases, collectively known as inflammatory bowel disease (IBD). IBD mainly affects the large intestine, but it can also affect the gastrointestinal tract as a whole. Its major symptoms are pain, diarrhea, and weight loss, and it is usually associated with deficiencies of both macro- and micronutrients. Unluckily, after some time the body develops resistance against the already available drugs: thus, many patients fail to maintain remission, which is achieved in less than 50% of cases. Diet is a major determinant of gut inflammation. An unbalanced diet can affect the gut microbiota and cause dysbiosis, which is related to a dysregulated host immune response. The Mediterranean Diet its renowned for its anti-inflammatory effects and for preventing dysbiosis. In order to improve management and treatment of intestinal inflammatory diseases, it should become common practice to integrate the patient’s diet with dietary supplements with anti-inflammatory effects (probiotics, butyrate, phosphatidylcholine, lactoferrin, palmitoylethanolamide, silymarin, and omega 3), which maintain the stability of the intestinal microbial cohort and strengthen the mucosal barrier, thus preventing or soothing IBD symptoms. Dietary supplements may help fight the high costs, the adverse side effects, and the recurrent relapses typical of drug use

Comparison of 5-year progression of retinitis pigmentosa involving the posterior pole among siblings by means of SD-OCT: a retrospective study

The blockchain technology promises to transform finance, money and evengovernments. However, analyses of blockchain applicability and robustness typicallyfocus on isolated systems whose actors contribute mainly by running the consensusalgorithm. Here, we highlight the importance of considering trustless platformswithin the broader ecosystem that includes social and communication networks. Asan example, we analyse the flash-crash observed on 21st June 2017 in the Ethereumplatform and show that a major phenomenon of social coordination led to acatastrophic cascade of events across several interconnected systems. We proposethe concept of “emergent centralisation” to describe situations where a single systembecomes critically important for the functioning of the whole ecosystem, and arguethat such situations are likely to become more and more frequent in interconnectedsocio-technical systems. We anticipate that the systemic approach we propose willhave implications for future assessments of trustless systems and call for the attentionof policy-makers on the fragility of our interconnected and rapidly changing world

From Achille Bertelli onward: more than 100 years of research and production of dietary supplements based on natural molecules typical of the Mediterranean diet

Achille Bertelli was an aeronautics pioneer and an innovative entrepreneur of the pharmaceutical industry. After graduating in Chemistry in Italy, he moved to the United States of America where he opened a chemical-pharmaceutical laboratory in San Francisco in 1879, and later moved back to Italy where he opened a chemical and pharmaceutical industry in Milan (1886). The “A. Bertelli” pharmaceutical company developed the famous cough pills “Catramina Bertelli”, as well as new cosmetics and perfumes. Apart from his chemical experience, Achille Bertelli was a passionate aeronautics expert. He wrote many essays on this topic and devoted himself to aeronautical experiments by designing theapparatus “Autovol”, “Aerocurvo”, “Autovol no. 2”, “Autovolno. 3", which are considered the prototypes of the helicopter. Achille Bertelli was also the president of the Electric Company of Salò, which installed an electrical system that served the lighting in many cities on Lake Garda (Italy). Finally, Achille Bertelli also participated in the Italian revival after the First World War, especially by supporting the agricultural revival. Throughout his life, Achille Bertelli teamed with several famous people from all over Italy, such as Gabriele D’Annunzio, Cesare Lombroso and Cordero di Montezemolo. Today, Achille Bertelli’s interest for natural molecules, his ideas, and his entrepreneurial approach are carried forward by his descendant, Matteo Bertelli

Genetic testing for Hennekam syndrome

Abstract Hennekam Syndrome (HS) is a combination of congenital lymphatic malformation, lymphangiectasia and other disorders. It is a very rare disorder with autosomal recessive inheritance. We developed the test protocol "Hennekam Syndrome" on the basis of the latest research findings and diagnostic protocols on lymphatic malformation in HS. The genetic test is useful for confirming diagnosis, as well as for differential diagnosis, couple risk assessment and access to clinical trials

Dietary supplements for polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most prevalent female endocrine reproductive disorders, affecting between 4 to 18% of the women in their reproductive age. It is generally characterized by several clinical aspects, among which anovulation, inflammation and infertility. Moreover, PCOS has several health implications, including increased metabolic, reproductive, and psychological risks. Previously, metformin and to some extent thiazolidinediones were considered as drug of choice for PCOS management, but they had several side-effects, and controversial results were obtained about their efficiency, especially in non-insulin-resistant non-obese patients. Thus, alternative treatment options are now being studied for PCOS, including different natural molecules and complementary medicines (CM) for the improvement of their health, wellbeing and fertility. Recently, treatment of PCOS patients with different natural molecules, coming from nutritional supplements and herbal medicines, has attained satisfactory results with the absence of any side effects. In this review, four natural molecules, curcumin, vitamin D, inositol and CoQ10 are discussed for their therapeutic ability. These molecules proved to decrease insulin sensitivity and inflammation, to improve the restoration of ovarian function, and they could restore hormonal balance and regulate the menstrual cycle, all of which are the main features and major concerns for women suffering from PCOS

Genetic testing for cystic hygroma

AbstractCystic hygroma (CH) is characterized by abnormal accumulation of fluid in the region of the fetal neck and is a major anomaly associated with aneuploidy. Morphologically characterized by failure of the lymphatic system to communicate with the venous system in the neck, the clinical manifestations of CH depend on its size and location. Incidence is estimated at one case per 6000-16,000 live births. CH has autosomal dominant or autosomal recessive inheritance. This Utility Gene Test was developed on the basis of an analysis of the literature and existing diagnostic protocols. It is useful for confirming diagnosis, as well as for differential diagnosis, couple risk assessment and access to clinical trials

Periconceptional Mediterranean Diet during Pregnancy on Children’s Health

During pregnancy, rapid and subtle physiological changes are observed from conception to birth. Nutrition and other lifestyle factors before and during pregnancy have been shown in the literature to influence the health of both mother and child. A healthy and varied diet during pregnancy can provide adequate energy and nutrients for both the mother and the growing fetus. Current research focuses on the periconceptional phase, which includes the early processes of gametogenesis, embryogenesis and placentation. A variety of abnormalities and pregnancy-related problems occur during this period, including congenital defects, fetal loss, miscarriage and preterm birth. A varied and balanced diet during periconception is important to maintain fetal development and growth. To date, numerous studies have been conducted to investigate the effects of consuming different nutrients, foods or food groups during pregnancy on the health of mother and child. For example, the Mediterranean diet is considered as a balanced, nutrient-rich diet due to the low consumption of meat products and fatty foods and the high consumption of vegetables, cheese, olive oil, fish, shellfish and little meat. While many studies have been conducted in the literature to investigate the effects of a Mediterranean diet during pregnancy on fetal health, the results have been inconclusive. The aim of this article is to review the current literature on the Mediterranean diet during pregnancy

Probing recent star formation with absorption-line strengths in hierarchical models and observations

Stellar population parameters derived from spectral line-strengths provide a powerful probe of galaxy properties and formation histories. We implement the machinery for extracting single-stellar-population-equivalent stellar population parameters from synthetic spectra generated by a hierarchical galaxy formation model. We find that the SSP-equivalent age is related to the light-weighted age in a complicated fashion that reflects the influence of recently-formed stars and is poorly correlated with the mass-weighted age. The tendency for SSP-equivalent ages to be biased young means that archaeological downsizing overstates the mass-weighted downsizing in age with mass. We find that the SSP-equivalent metallicity closely tracks the mass- and light-weighted metallicities, so that observed mass--metallicity relations for old galaxies closely reflect the underlying trends. We construct mock catalogues of early-type galaxies in a Coma cluster-sized halo and compare them directly to observations of early-type galaxies in the Coma cluster. The similarity of the SSP-equivalent ages in the observational samples and the mock catalogues gives us confidence that the star-formation quenching implemented in the hierarchical galaxy formation model produces roughly the correct amount of recent star formation. The SSP-equivalent metallicities are however too low and have the wrong slope as a function of velocity dispersion, and the SSP-equivalent ages of the model galaxies may have an incorrect slope as a function of velocity dispersion. (Abridged)Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society. 17 page