52 research outputs found
Progetto "Total Clean Injector" in una linea di produzione iniettori ad alta pressione
Questo studio, svoltosi in collaborazione con la Continental Italy S.p.A. di Pisa, ha avuto come scopo la pianificazione e la messa in pratica di un progetto, denominato “Total Clean Injector”, per l’analisi, la mappatura e la riduzione della contaminazione relativamente alla produzione dell’iniettore ad alta pressione.
L’analisi ha compreso la contaminazione proveniente dalla linea, dai ritorni cliente, da determinate tipologie di scarti e da alcune tipologie di filtri utilizzate durante le attività di test degli iniettori stessi. Congiuntamente alle attività di analisi è stata effettuata l’individuazione delle root causes e l’applicazione di azioni correttive e contenitive mirate alla riduzione della contaminazione, in un continuo ciclo di miglioramento.
Oltre a ciò è stato fornito all’area di produzione un metodo di validità generale che potrà permettere un monitoraggio della contaminazione sui componenti in ingresso alla linea, direttamente in Clean Room e con un riscontro in tempo reale; metodo confluito nell’istruzione CAI 0600748
Numerical Analysis of a Low NOx Partially Premixed Burner for Industrial Gas Turbine Applications
Abstract A numerical analysis of a low NOx partially premixed burner for industrial gas turbine applications is presented. In the first part the mixing inside a double annular counter-rotating swirl nozzle where the fuel is injected in a transverse jet configuration is studied. Standard k – ∈ model and Two variable Schmidt number models were assessed in order to find a reliable configuration able to fit the available experimental profiles. Resulting profiles are used to perform reactive simulations of the experimental test rig, where NOx, CO measurement were available Results are compared in terms of NOx concentration at the outlet with experimental data
PRELIMINARY STUDY FOR SEISMIC ASSESSMENT OF THE UNDERGROUND FACILITIES AT POINT 5 OF THE LARGE HADRON COLLIDER (LHC) AT CERN
The European Organisation for Nuclear Research (CERN) is continuously upgrading its extensive underground facilities to cope with the need for new and more complex experiments. The Large Hadron Collider (LHC) houses the Compact Muon Solenoid (CMS) detector at its Point 5, where there are two large shafts, two 100 m deep major parallel caverns, with a total span of 50 m, separated by a 7 m wide and 28 m high concrete pillar, and a system of secondary tunnels and caverns. Such a complex underground infrastructure lies in a sedimentary rock formation (red molasse) of the Geneva basin, with a low rock cover of about 20 m to the overlying 50 m thick layer of water bearing moraine. The site is classified as a zone of moderate seismicity and the underground structures were designed against a “standard” seismic risk, that corresponds to the importance category II according to Eurocode 8. To study the dynamic response of the caverns to seismic waves, a series of Finite Element (FE) full dynamic analyses have been carried out, where the non-linear behavior of the underground layers has been carefully modelled. A suite of input signals that comply with the design spectrum has been applied to the model. The preliminary results are commented in the paper to define the seismic safety requirement for the sensitive infrastructures and installations located inside the tunnels and caverns.</p
PRELIMINARY STUDY FOR SEISMIC ASSESSMENT OF THE UNDERGROUND FACILITIES AT POINT 5 OF THE LARGE HADRON COLLIDER (LHC) AT CERN
The European Organisation for Nuclear Research (CERN) is continuously upgrading its extensive underground facilities to cope with the need for new and more complex experiments. The Large Hadron Collider (LHC) houses the Compact Muon Solenoid (CMS) detector at its Point 5, where there are two large shafts, two 100 m deep major parallel caverns, with a total span of 50 m, separated by a 7 m wide and 28 m high concrete pillar, and a system of secondary tunnels and caverns. Such a complex underground infrastructure lies in a sedimentary rock formation (red molasse) of the Geneva basin, with a low rock cover of about 20 m to the overlying 50 m thick layer of water bearing moraine. The site is classified as a zone of moderate seismicity and the underground structures were designed against a “standard” seismic risk, that corresponds to the importance category II according to Eurocode 8. To study the dynamic response of the caverns to seismic waves, a series of Finite Element (FE) full dynamic analyses have been carried out, where the non-linear behavior of the underground layers has been carefully modelled. A suite of input signals that comply with the design spectrum has been applied to the model. The preliminary results are commented in the paper to define the seismic safety requirement for the sensitive infrastructures and installations located inside the tunnels and caverns.</p
Cardiac Magnetic Resonance to Predict Cardiac Mass Malignancy: The CMR Mass Score
Background: Multimodality imaging is currently suggested for the noninvasive diagnosis of cardiac masses. The identification of cardiac masses' malignant nature is essential to guide proper treatment. We aimed to develop a cardiac magnetic resonance (CMR)-derived model including mass localization, morphology, and tissue characterization to predict malignancy (with histology as gold standard), to compare its accuracy versus the diagnostic echocardiographic mass score, and to evaluate its prognostic ability. Methods: Observational cohort study of 167 consecutive patients undergoing comprehensive echocardiogram and CMR within 1-month time interval for suspected cardiac mass. A definitive diagnosis was achieved by histological examination or, in the case of cardiac thrombi, by histology or radiological resolution after adequate anticoagulation treatment. Logistic regression was performed to assess CMR-derived independent predictors of malignancy, which were included in a predictive model to derive the CMR mass score. Kaplan-Meier curves and Cox regression were used to investigate the prognostic ability of predictors. Results: In CMR, mass morphological features (non-left localization, sessile, polylobate, inhomogeneity, infiltration, and pericardial effusion) and mass tissue characterization features (first-pass perfusion and heterogeneity enhancement) were independent predictors of malignancy. The CMR mass score (range, 0-8 and cutoff, ≥5), including sessile appearance, polylobate shape, infiltration, pericardial effusion, first-pass contrast perfusion, and heterogeneity enhancement, showed excellent accuracy in predicting malignancy (areas under the curve, 0.976 [95% CI, 0.96-0.99]), significantly higher than diagnostic echocardiographic mass score (areas under the curve, 0.932; P=0.040). The agreement between the diagnostic echocardiographic mass and CMR mass scores was good (κ=0.66). A CMR mass score of ≥5 predicted a higher risk of all-cause death (P<0.001; hazard ratio, 5.70) at follow-up. Conclusions: A CMR-derived model, including mass morphology and tissue characterization, showed excellent accuracy, superior to echocardiography, in predicting cardiac masses malignancy, with prognostic implications
siRNA screen identifies QPCT as a druggable target for Huntington's disease.
Huntington's disease (HD) is a currently incurable neurodegenerative condition caused by an abnormally expanded polyglutamine tract in huntingtin (HTT). We identified new modifiers of mutant HTT toxicity by performing a large-scale 'druggable genome' siRNA screen in human cultured cells, followed by hit validation in Drosophila. We focused on glutaminyl cyclase (QPCT), which had one of the strongest effects on mutant HTT-induced toxicity and aggregation in the cell-based siRNA screen and also rescued these phenotypes in Drosophila. We found that QPCT inhibition induced the levels of the molecular chaperone αB-crystallin and reduced the aggregation of diverse proteins. We generated new QPCT inhibitors using in silico methods followed by in vitro screening, which rescued the HD-related phenotypes in cell, Drosophila and zebrafish HD models. Our data reveal a new HD druggable target affecting mutant HTT aggregation and provide proof of principle for a discovery pipeline from druggable genome screen to drug development
Numerical assessment of CO<sub>2</sub>-based mixtures for refrigeration systems: focus on the evaporation process
A large number of refrigeration systems operate on a stream that is not changing phase, i.e. has a finite heat capacity. The matching between the cooled stream and the evaporation of a pure refrigerant causes therefore significant irreversibility in the heat exchange. The use of mixtures is a well-known option for the mitigation of this problem. In this work, the use of a CO2-based mixture is proposed to allow the possibility of matching variable-temperature heat sources with the glide of the working fluid in the evaporator to minimize the heat exchange irreversibility. Modelling of a mini-channel evaporator by means of numerical techniques, accounting for the variable fluid composition, is presented. Several flow boiling correlations are assessed for pure CO2 (170<G<900) and for CO2-propane blends (200<G<650). An optimized correlation for CO2-propane is proposed. As a final result, a high fidelity CO2 correlation for flow boiling is presented, which is also able to predict quite accurately the CO2-propane mixture heat transfer coefficient.<br/
The soluble Y115E-Y117E variant of human glutaminyl cyclase is a valid target for X-ray and NMR screening of inhibitors against Alzheimer disease
Recent developments in molecular pathology and genetics have allowed the identification of human glutaminyl cyclase (hQC) among the abnormal proteins involved in many neurodegenerative disorders. Difficulties in obtaining large quantities of pure protein may limit the use of crystallographic screening for drug development on this target. Site-directed mutagenesis experiments have led to the identification of some solvent-exposed residues that are absolutely critical to achieve increased solubility and to avoid precipitation of the enzyme in inclusion bodies when expressed in Escherichia coli. The designed variant Y115E-Y117E has been found to be able to provide large amounts of monodisperse, pure hQC from an E. coli expression system. To validate the use of the artificial construct as a target for large-scale X-ray and NMR screening campaigns in the search for new inhibitors of hQC, the X-ray crystal structures of the hQC Y115E-Y117E variant and of its adduct with the inhibitor PBD-150 were determined
Experimental and Numerical Investigations of Novel Natural Gas Low NOx Burners for Heavy Duty Gas Turbine
Design Improvement Survey for NOx Emissions Reduction of a Heavy-Duty Gas Turbine Partially Premixed Fuel Nozzle Operating With Natural Gas: Numerical Assessment
- …