52 research outputs found

    Application of the EGM Method to a LED-Based Spotlight: A Constrained Pseudo-Optimization Design Process Based on the Analysis of the Local Entropy Generation Maps

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    In this paper, the entropy generation minimization (EGM) method is applied to an industrial heat transfer problem: the forced convective cooling of a LED-based spotlight. The design specification calls for eighteen diodes arranged on a circular copper plate of 35 mm diameter. Every diode dissipates 3 W and the maximum allowedtemperature of the plate is 80 °C. The cooling relies on the forced convection driven by a jet of air impinging on the plate. An initial complex geometry of plate fins is presented and analyzed with a commercial CFD code that computes the entropy generation rate. A pseudo-optimization process is carried out via a successive series of design modifications based on a careful analysis of the entropy generation maps. One of the advantages of the EGM method is that the rationale behind each step of the design process can be justified on a physical basis. It is found that the best performance is attained when the fins are periodically spaced in the radial direction

    Surrogate models for the prediction of the aerodynamic performance of exhaust systems

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    The aerodynamic performance of the exhaust system is becoming more important in the design of engines for civil aircraft applications. To increase propulsive efficiency and reduce specific fuel consumption, it is expected that future engines will operate with higher bypass ratios, lower fan pressure ratios and lower specific thrust. At these operating conditions, the net thrust and the specific fuel consumption are more sensitive to losses in the exhaust. Thus the performance of the exhaust needs to be accurately assessed as early as possible during the design process. This research investigates low-order models for the prediction of the performance of separate-jet exhaust systems, as a function of the free-stream Mach number, the fan nozzle pressure ratio and the extraction ratio (fan to core pressure ratio). In the current practice the two nozzles are typically considered in isolation and the performance is modelled as a function of their pressure ratio. It is shown that the additional degrees of freedom have a substantial impact on the metrics describing the performance of the exhaust system. These models can be employed at a preliminary design stage coupled with engine performance models, which require as input the characteristics of the exhaust system. Two engines, which are representative of current and future large turbofan architectures are studied. The low-order models investigated, generalized Kriging and radial basis functions, are constructed based on data obtained with computational fluid dynamics simulations. The data represents the characteristics of the exhaust of each engine, and they are provided for the first time for a wide operational envelope. The influence on accuracy of the type of surragate model and its settings have been quantified. Furthermore, the trade-off between the accuracy of the model and the number of samples has been identified. It is found that the exhaust performance metrics can be modelled using a low-order model with sufficient accuracy. Recommendations on the best settings of the model are also provided

    Aggiornamenti epidemiologici sull’echinococcosi animale in Italia

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    Cystic Echinococcosis (CE) is one of the most widespread parasitoses in the Mediterranean Region (MR). This is due to various factors, the most important being the close association between man, sheep and dogs in areas where open farming is practised. Although this disease has been known for several years and many studies have been carried out, nowadays in Italy there are no complete epidemiological data on its diffusion and distribution. The available data show that CE is mainly diffused in those districts where the sheep-dog cycle can be perpetuated, such as central and southern Italy, and the islands. Furthermore, no data are available on biomolecular characterisation of the strains of Echinococcus granulosus in Italy, apart form those in Sardinia, where the G1 (sheep-dog) and G7 (pig-dog) strains were recently isolated. One of the reasons why CE is a problem with no easy solution is undoubtedly the difficulty of making a certain diagnosis in the dog, the principal definitive host of E. granulosus

    Human leukocyte antigen (Hla) haplotype does not influence the inflammatory pattern of duodenal lymphocytosis linked to irritable bowel syndrome

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    Background and objectives: Duodenal lymphocytosis (DL) is a condition characterized by enhanced infiltration of intraepithelial lymphocytes (IELs) in the duodenal mucosa, and it can be linked to both gluten-and non-gluten-related diseases, such as irritable bowel syndrome (IBS). Materials and methods: We retrospectively selected patients with DL linked to IBS. Formalin-embedded biopsy samples of the duodenum were collected. CD3 lymphocyte immunohistochemistry was used for IELs. The real-time polymerase chain reaction was used to quantify the amount of mRNA coding for tissue transglutaminase 2 (tTG2), interferon-gamma (IFNγ), toll-like receptor 2 (TLR2), and myeloid differentiation primary response 88 (MyD88). All subjects underwent DQ2-8 haplotype analysis. Controls were represented by subjects with IBS without DL. Results: Thirty-two patients with IBS-DL were retrospectively recruited. Fourteen subjects (43.8%) had a DQ2-8 haplotype. DQ2-8 positive subjects had similar levels compared to negative ones for tTG2, IFNγ, TLR2, and MyD88. Cigarette smoke did not influence molecular expression in our study. Smokers had a statistically higher IELs count than non-smokers (54.2 ± 7.7 vs. 36.0 ± 8.8, p < 0.001). A significant, direct correlation between IELs and duodenal expression of IFNγ was found (r = 0.36, p = 0.04). Conclusions: IBS with DL showed higher expression of inflammatory markers than controls, but DQ2-8 haplotype did not seem to affect their expression. Smoking might increase IELs infiltration

    QUADRUPLE RESCUE THERAPY AFTER FIRST AND SECOND LINE FAILURE FOR HELICOBACTER PYLORI TREATMENT: COMPARISON BETWEEN TWO TETRACYCLINE-BASED REGIMENS

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    Background & Aims: Antibiotic resistance is the main reason for failure of Helicobacter pylori (H. pylori) treatment. Currently, guidelines recommend a treatment guided by antimicrobial susceptibility testing after two failures. However, microbial culture is not feasible everywhere, and the limited number of effective antibiotics against the bacterium narrows the options; thus a rescue therapy combining antibiotics with a low resistance may be fitting. Methods: Patients who have failed a first-line treatment (either prolonged triple or sequential regimens) and, successively, a levofoxacin-based triple therapy were considered for the study. Subjects underwent urea breath test (UBT), stool antigen test (ST) and endoscopy/histology to confirm the diagnosis. Cytopenia and impaired liver and kidney function were exclusion criteria. Fify-four subjects were randomized 1:1 to two regimens: RMB abeprazole/Rifabutin/Minocycline/Bismuth sub-citrate or MTB Rabeprazole/Tinidazole/ Minocycline/Bismuth sub-citrate both for 10 days. Te results were checked 6 weeks afer the end of therapy with ST/UBT plus endoscopy when indicated. Results: RMB eradicated the bacterium in 21 patients. Two subjects dropped out. Te eradication rate was 77.7% (CI 62.0-93.4%) at intention-to-treat and 84.0% (CI 69.6-98.4%) at per-protocol analysis. MTB was successful in 14 patients (51.9%, CI 33.1-70.7%). No patient withdrew from the treatment for adverse events. Drug-related side effects were reported only in 3 subjects, but in all cases the treatment was carried on. Conclusions: Te association minocycline/rifabutin seems to have a synergic effect and a good therapeutic outcome in patients who have failed at least two previous regimens, although a trial on a large population is needed

    Evolution of nonspecific duodenal lymphocytosis over 2 years of follow-up

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    AIM: To assess the evolution of duodenal lymphocytosis (DL), a condition characterized by increased intraepithelial lymphocytes (IELs), over 2 years of follow-up. METHODS: Consecutive patients undergoing upper endoscopy/histology for abdominal pain, diarrhea, weight loss, weakness or other extraintestinal features compatible with celiac disease (CD) were included. Evaluation of IELs infiltrate in duodenal biopsy samples was carried out by CD3-immunohistochemistry and expressed as number of positive cells/100 enterocytes. Diagnostic agreement on the IELs count was tested by calculating the weighted k coefficient. All patients underwent serological detection of autoantibodies associated with CD: IgG and IgA anti-tissue transglutaminase and endomysium. Each patient underwent further investigations to clarify the origin of DL at baseline and/or in the course of 2 years of follow-up every six months. Autoimmune thyroiditis, intestinal infections, parasitic diseases, bacterial intestinal overgrowth, hypolactasia and wheat allergy were detected. Colonoscopy and enteric magnetic resonance imaging were performed when necessary. Risk factors affecting the final diagnosis were detected by multinomial logistic regression and expressed as OR. RESULTS: Eighty-five patients (16 males, 69 females, aged 34.1 ± 12.5 years) were followed up for a mean period of 21.7 ± 11.7 mo. At baseline, endoscopy/duodenal biopsy, CD3 immunohistochemistry revealed: > 25 IELs/100 enterocytes in 22 subjects, 15-25 IELs in 37 and < 15 IELs in 26. They all had negative serum anti-transglutaminase and anti-endomysium, whilst 5 showed IgG anti-gliadin positivity. In the course of follow-up, 23 developed CD seropositivity and gluten sensitivity (GS) was identified in 19. Other diagnoses were: 5 Helicobacter pylori infections, 4 jejunal Crohn's disease, 1 lymphocytic colitis and 1 systemic sclerosis. The disease in the remaining 32 patients was classified as irritable bowel syndrome because of the lack of diagnostic evidence. At multivariate analysis, the evolution towards CD was associated with an IELs infiltrate > 25 (OR = 1640.4) or 15-25 (OR = 16.95), human leukocyte antigen (HLA) DQ2/8 (OR = 140.85) or DQA1∗0501 (OR = 15.36), diarrhea (OR = 5.56) and weakness (OR = 11.57). GS was associated with IELs 15-25 (OR = 28.59), autoimmune thyroiditis (OR = 87.63), folate deficiency (OR = 48.53) and diarrhea (OR = 54.87). CONCLUSION: DL may have a multifactorial origin but the IELs infiltrate and HLA are strong predictive factors for CD development and a clinical diagnosis of GS

    La citt\ue0 metropolitana di Trieste

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    Verso la fine del 2012 la Regione Friuli Venezia Giulia ha conferito l\u2019incarico all\u2019Universit\ue0 degli Studi di Trieste di effettuare uno studio su un\u2019ipotesi di \u201cCitt\ue0 metropolitana di Trieste\u201d. Il primo passo \ue8 stata la ricognizione degli ambiti disciplinari e delle competenze utili per analizzare il tema. Sono stati individuati quattro ambiti che indicheremo come: \u2022 Ambito urbanistico-territoriale \u2022 Ambito economico-trasportistico \u2022 Ambito socio-politico \u2022 Ambito giuridico-legislativo Pur non essendo esaustivo, ciascuno di questi ambiti ha un sicuro rilievo nel definire e valutare l\u2019impatto che la costituzione della citt\ue0 metropolitana potrebbe avere rispetto all\u2019assetto territoriale, economico, sociale e amministrativo esistente. Si \ue8 quindi formato un ampio gruppo di ricerca proveniente da studiosi appartenenti a quattro diversi Dipartimenti: il Dipartimento di Ingegneria e Architettura, il Dipartimento di Scienze Economiche, Aziendali, Matematiche e Statistiche, il Dipartimento di Scienze Politiche e Sociali e il Dipartimento di Scienze Giuridiche, del Linguaggio, dell`Interpretazione e della Traduzione. Per il Dipartimento di Ingegneria e Architettura hanno partecipato Paola Di Biagi, Alessandra Marin, Claudia Marcon e Igor Ciuffarin; per il Dipartimento di Scienze Economiche, Aziendali, Matematiche e Statistiche Romeo Danielis, Lucia Rotaris; per il Dipartimento di Scienze Politiche e Sociali Giorgio Osti, Giovanni Carrosio e Marco Cesa; e per il Dipartimento di Scienze Giuridiche, del Linguaggio, dell`Interpretazione e della Traduzione Paolo Giangaspero, Alessia Ottavia Cozzi, Pietro Faraguna e Federico Gambini. La provenienza multidisciplinare del gruppo di ricerca ha permesso di evidenziare le specificit\ue0 di ciascuna disciplina nell\u2019affrontare il tema oggetto di studio e di metterle a confronto, facendole interagire, nel caso specifico dell\u2019ipotesi della Citt\ue0 Metropolitana di Trieste

    La città metropolitana di Trieste. Analisi territoriale economica, sociologica, giuridica

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    Verso la fine del 2012 la Regione Friuli Venezia Giulia ha conferito l’incarico all’Università degli Studi di Trieste di effettuare uno studio sull’ipotesi di “Città metropolitana di Trieste”. Il volume raccoglie i materiali predisposti da un gruppo di ricerca formato da studiosi appartenenti al Dipartimento di Ingegneria e Architettura, al Dipartimento di Scienze Economiche, Aziendali, Matematiche e Statistiche, al Dipartimento di Scienze Politiche e Sociali e al Dipartimento di Scienze Giuridiche, del Linguaggio, dell`Interpretazione e della Traduzione. Il tema è stato analizzato da quattro punti di vista: urbanistico-territoriale, economico-trasportistico, socio-politico e giuridico-legislativo. Lo studio si è concluso nel maggio 2014. Contiene ampie sezioni analitiche e un capitolo finale in cui sono commentate, dai diversi punti di vista, tre distinte ipotesi di dimensionamento della città metropolitana di Trieste: a) una equivalente all’attuale provincia di Trieste; b) una equivalente alle attuali province di Trieste e Gorizia; c) una equivalente all’area litoranea comprendente Monfalcone, Trieste e Capodistria
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