Digital Governance: Leading and Thriving in a World of Fast-Changing Technologies

Ferrero Federico 한국행정학회 2022 International Review of Public Administration Vol.27 No.4

Unstructured discretisation of a non-local transition model for turbomachinery flows

Ferrero, Andrea,Larocca, Francesco,Bernaschek, Verena Techno-Press 2017 Advances in aircraft and spacecraft science Vol.4 No.5

The description of transitional flows by means of RANS equations is sometimes based on non-local approaches which require the computation of some boundary layer properties. In this work a non-local Laminar Kinetic Energy model is used to predict transitional and separated flows. Usually the non-local term of this model is evaluated along the grid lines of a structured mesh. An alternative approach, which does not rely on grid lines, is introduced in the present work. This new approach allows the use of fully unstructured meshes. Furthermore, it reduces the grid-dependence of the predicted results. The approach is employed to study the transitional flows in the T106c turbine cascade and around a NACA0021 airfoil by means of a discontinuous Galerkin method. The local nature of the discontinuous Galerkin reconstruction is exploited to implement an adaptive algorithm which automatically refines the mesh in the most significant regions.

A hybrid numerical flux for supersonic flows with application to rocket nozzles

Ferrero, Andrea,D'Ambrosio, Domenic Techno-Press 2020 Advances in aircraft and spacecraft science Vol.7 No.5

The numerical simulation of shock waves in supersonic flows is challenging because of several instabilities which can affect the solution. Among them, the carbuncle phenomenon can introduce nonphysical perturbations in captured shock waves. In the present work, a hybrid numerical flux is proposed for the evaluation of the convective fluxes that avoids carbuncle and keeps high-accuracy on shocks and boundary layers. In particular, the proposed flux is a combination between an upwind approximate Riemann problem solver and the Local Lax-Friedrichs scheme. A simple strategy to mix the two fluxes is proposed and tested in the framework of a discontinuous Galerkin discretisation. The approach is investigated on the subsonic flow in a channel, on the supersonic flow around a cylinder, on the supersonic flow on a flat plate and on the flow in a overexpanded rocket nozzle.

Chinese Classics in Matteo Ricci’s 天主实义 and its reception in Korea

Michele Ferrero 고려대학교 한자한문연구소 2010 동아한학연구 Vol.- No.6

Matteo Ricci’s (利?? 1552-1610) 天主?? (“The true meaning of the Lord of Heaven”) is “an unrivalled example of meeting between Chinese Classics and Christianity” but also marks the beginning of the acceptance of Christianity in Korea. Yi Su-gwang known as Jibong (1563-1628), one of the leading figures of the time, introduced in Korea both Western and Catholic knowledge, through the mediation of the Confucian Chinese books of Matteo Ricci and his friends. The 天主?? was explicitly written in dialogue with Confucianism and all the main topics of the treatise are presented in connection with the Chinese Classics: the existence of God; the human soul; the debate whether the soul is some energy or it is spirit; the issue of reincarnation; the cultivation of moral virtue; the connection between actions, intention and reward; the goodness of human nature.

Immunonutrition in ovarian cancer: clinical and immunological impact?

Annamaria Ferrero,Daniela Vassallo,Massimo Geuna,Luca Fuso,Michela Villa,Enrico Badellino,Martina Barboni,Paola Coata,Nathalie Santoro,Roberto C. Delgado Bolton,Nicoletta Biglia 대한부인종양학회 2022 Journal of Gynecologic Oncology Vol.33 No.6

Objective: Malnutrition is frequent in ovarian cancer (OC) patients and may compromise post-operative outcomes. The aim of this study is to evaluate the impact of pre-operative immunonutrition on the surgical outcome of OC patients, and on their nutritional, inflammatory and peripheral blood immune status. Methods: A prospective study was performed between September 2016 and April 2020. Immune-enhancing enteral nutrition was administered to 42 patients before surgery according to their nutritional status assessed by the Malnutritional Universal Screening Tool. Biochemical and hematological monitoring was performed before and after immunonutrition. Post-operative outcomes were assessed and compared with those of a similar group of patients treated without nutritional support. Results: Of the 42 immune-nourished patients, 23 (54.8%) had a low, 11 (26.2%) an intermediate and 8 (19%) a high risk of malnutrition. After the immunonutritional intake, significant variations of prealbumin, creatinine and white blood cells were detected. All T cell populations had an increasing trend, in particular CD3+ T lymphocytes (p=0.020), CD3+CD8+ cytotoxic T lymphocytes (p=0.046) and lymphocyte with HLA-DR expression (p=0.012). The rate of grade II–III post-operative complications was lower (21.4% vs. 42.9%, p=0.035) and the time of hospitalization was shorter (7.5 vs. 9.2, p=0.009) in the immune-nourished group. Conclusion: Pre-operative immunonutrition improves the surgical outcome of OC patients. After immunonutrition, an increase of CD3+CD8+ cytotoxic T lymphocytes was observed.

Metabolic Crosstalk between the Heart and Fat

Kimberly M. Ferrero,Walter J. Koch 대한심장학회 2020 Korean Circulation Journal Vol.50 No.5

It is now recognized that the heart can behave as a true endocrine organ, which can modulate the function of other tissues. Emerging evidence has shown that visceral fat is one such distant organ the heart communicates with. In fact, it appears that bi-directional crosstalk between adipose tissue and the myocardium is crucial to maintenance of normal function in both organs. In particular, factors secreted from the heart are now known to influence the metabolic activity of adipose tissue and other organs, as well as modulate the release of metabolic substrates and signaling molecules from the periphery. This review summarizes current knowledge regarding primary cardiokines and adipokines involved in heart-fat crosstalk, as well as implications of their dysregulation for cardiovascular health.

Numerical investigation for performance prediction of gas dynamic resonant igniters

Conte, Antonietta,Ferrero, Andrea,Pastrone, Dario Techno-Press 2020 Advances in aircraft and spacecraft science Vol.7 No.5

The work presented herein is a numerical investigation of the flow field inside a resonant igniter, with the aim of predicting the performances in terms of cavity temperature and noise spectrum. A resonance ignition system represens an attractive solution for the ignition of liquid rocket engines in space missions which require multiple engine re-ignitions, like for example debris removal. Furthermore, the current trend in avoiding toxic propellants leads to the adoption of green propellant which does not show hypergolic properties and so the presence of a reliable ignition system becomes fundamental. Resonant igniters are attractive for in-space thrusters due to the low weight and the absence of an electric power source. However, their performances are strongly influenced by several geometrical and environmental parameters. This motivates the study proposed in this work in which the flow field inside a resonant igniter is numerically investigated. The unsteady compressible Reynolds Averaged Navier-Stokes equations are solved by means of a finite volume scheme and the effects of several wall boundary conditions are investigated (adiabatic, isothermal, radiating). The results are compared with some available experimental data in terms of cavity temperature and noise spectrum.

Photon-Counting Detector CT: Key Points Radiologists Should Know

Esquivel Andrea,Ferrero Andrea,Mileto Achille,Baffour Francis,Horst Kelly,Rajiah Prabhakar Shantha,Inoue Akitoshi,Leng Shuai,McCollough Cynthia,Fletcher Joel G. 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.9

Photon-counting detector (PCD) CT is a new CT technology utilizing a direct conversion X-ray detector, where incident X-ray photon energies are directly recorded as electronical signals. The design of the photon-counting detector itself facilitates improvements in spatial resolution (via smaller detector pixel design) and iodine signal (via count weighting) while still permitting multi-energy imaging. PCD-CT can eliminate electronic noise and reduce artifacts due to the use of energy thresholds. Improved dose efficiency is important for low dose CT and pediatric imaging. The ultra-high spatial resolution of PCD-CT design permits lower dose scanning for all body regions and is particularly helpful in identifying important imaging findings in thoracic and musculoskeletal CT. Improved iodine signal may be helpful for low contrast tasks in abdominal imaging. Virtual monoenergetic images and material classification will assist with numerous diagnostic tasks in abdominal, musculoskeletal, and cardiovascular imaging. Dual-source PCD-CT permits multi-energy CT images of the heart and coronary arteries at high temporal resolution. In this special review article, we review the clinical benefits of this technology across a wide variety of radiological subspecialties.

Reynolds stress correction by data assimilation methods with physical constraints

Thomas Philibert,Andrea Ferrero,Angelo Iollo,Francesco Larocca Techno-Press 2023 Advances in aircraft and spacecraft science Vol.10 No.6

Reynolds-averaged Navier-Stokes (RANS) models are extensively employed in industrial settings for the purpose of simulating intricate fluid flows. However, these models are subject to certain limitations. Notably, disparities persist in the Reynolds stresses when comparing the RANS model with high-fidelity data obtained from Direct Numerical Simulation (DNS) or experimental measurements. In this work we propose an approach to mitigate these discrepancies while retaining the favorable attributes of the Menter Shear Stress Transport (SST) model, such as its significantly lower computational expense compared to DNS simulations. This strategy entails incorporating an explicit algebraic model and employing a neural network to correct the turbulent characteristic time. The imposition of realizability constraints is investigated through the introduction of penalization terms. The assimilated Reynolds stress model demonstrates good predictive performance in both in-sample and out-of-sample flow configurations. This suggests that the model can effectively capture the turbulent characteristics of the flow and produce physically realistic predictions.

RANS simulation of secondary flows in a low pressure turbine cascade: Influence of inlet boundary layer profile

Michele, Errante,Andrea, Ferrero,Francesco, Larocca Techno-Press 2022 Advances in aircraft and spacecraft science Vol.9 No.5

Secondary flows have a huge impact on losses generation in modern low pressure gas turbines (LPTs). At design point, the interaction of the blade profile with the end-wall boundary layer is responsible for up to 40% of total losses. Therefore, predicting accurately the end-wall flow field in a LPT is extremely important in the industrial design phase. Since the inlet boundary layer profile is one of the factors which most affects the evolution of secondary flows, the first main objective of the present work is to investigate the impact of two different inlet conditions on the end-wall flow field of the T106A, a well known LPT cascade. The first condition, labeled in the paper as C1, is represented by uniform conditions at the inlet plane and the second, C2, by a flow characterized by a defined inlet boundary layer profile. The code used for the simulations is based on the Discontinuous Galerkin (DG) formulation and solves the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the Spalart Allmaras turbulence model. Secondly, this work aims at estimating the influence of viscosity and turbulence on the T106A end-wall flow field. In order to do so, RANS results are compared with those obtained from an inviscid simulation with a prescribed inlet total pressure profile, which mimics a boundary layer. A comparison between C1 and C2 results highlights an influence of secondary flows on the flow field up to a significant distance from the end-wall. In particular, the C2 end-wall flow field appears to be characterized by greater over turning and under turning angles and higher total pressure losses. Furthermore, the C2 simulated flow field shows good agreement with experimental and numerical data available in literature. The C2 and inviscid Euler computed flow fields, although globally comparable, present evident differences. The cascade passage simulated with inviscid flow is mainly dominated by a single large and homogeneous vortex structure, less stretched in the spanwise direction and closer to the end-wall than vortical structures computed by compressible flow simulation. It is reasonable, then, asserting that for the chosen test case a great part of the secondary flows details is strongly dependent on viscous phenomena and turbulence.