1,354,163 research outputs found
Unsteady stokes flow for a vibrating cantilever under a free-surface
No full textVibration of a thin, rectangular-cross-section beam submerged in a viscous, quiescent fluid undergoing small amplitude oscillations is studied using a Boundary Element (BE) approach in which the free-surface is modeled through a stress-free boundary condition. The Stokes approximation is used where nonlinear convective terms are negligible and the problem is formulated in Fourier and Laplace transform space when appropriate. Results are expressed in terms of nondimensional hydrodynamic force and its components, namely added mass and damping coefficients. Several parametric studies are conducted to evaluate the effects of depth of submergence, frequency and the amplitude of oscillations on the hydrodynamic functions. The results are compared with the classical solution for a vibrating lamina in an infinite fluid as the limit case and with a recent study using Smoothed Particle Hydrodynamics (SPH) analysis in the presence of a freesurface
Multiscale Smoothed Particle Hydrodynamics based on a domain-decomposition strategy
No full textA multi-resolution algorithm for weakly-compressible Smoothed Particle Hydrodynamics is hereby proposed. The approach chosen is based on a domain decomposition to subdivide the computational domain into regions with different resolutions. Each sub-problem is closed by appropriate Dirichlet boundary conditions that are enforced via buffer regions, populated by particles whose physical quantities are obtained by means of an interpolation over adjacent sub-domains. The algorithm has been implemented into the DualSPHysics open-source code and it has been tested and validated through a series of different study cases. The capability of the numerical scheme to simulate multiscale fluid flow has been demonstrated by solving the flow past a cylinder for a Reynolds number of 9,500 and a ratio between the largest and smallest particle size equal to 28. Furthermore, the proposed SPH multi-resolution algorithm can also be used for flow around moving objects, such as an oscillating cylinder in cross-flow, and free-surface flow, such as the simulation of a triangular wedge impacting on the free surface of a quiescent liquid
Direct numerical simulation of three-dimensional isotropic turbulence with smoothed particle hydrodynamics
No full textSmoothed Particle Hydrodynamics vs Lattice Boltzmann for the solution of steady and unsteady fluid flows
No full textNumerical simulations of steady and unsteady viscous flows are presented by adopting two different numerical methodologies: the Smoothed Particle Hydrodynamics formulation implemented in the open-source code DualSPHysics and an in-house lattice Boltzmann code based on a concise central-moments scheme. Both methods employ a weakly compressible assumption to simulate incompressible flow, which means the fluid is assumed barotropic and the density and pressure are related through an equation of state. The accuracy of the two approaches is evaluated against well-defined and consolidated benchmark tests. Advantages and disadvantages of the two methodologies are discussed and substantiated by quantitative comparisons that focus on accuracy and efficacy of the two methodologies against other well-established computational methods. Overall, both formulations proposed herein are able to capture the relevant flow physics with a good level of accuracy when compared to other more affirmed techniques. Remarkably, this is observed in spite of the proposed two methods lacking key strategies commonly used in grid-based methods, such as adaptive mesh refinement
A Survey on the Effects of Advertising of Unhealthy Food on the Decision of Students
No full textCERNELEV, Olga, TAFUNI, Ovidiu. A Survey on the Effects of Advertising of Unhealthy Food on the Decision of Students. Eastern European Journal of Regional Studies. December 2016, vol. 2, issue 2, pp. 74-82. ISSN 2537-6179; E-ISSN 1857-436X.The purpose of the research was to assess the effects of advertising of unhealthy food products on student's decision and eating behavior. In the present research participated 272 students aged between 18-29 years from the State University of Medicine and Pharmacy “Nicolae Testemitanu” from the Republic of Moldova. Unfortunately, the findings showed that promotional policy of companies in the food sector have escalated and can influence food product purchase behavior among students
La valutazione dell'esperienza di tirocinio : una ricerca preliminare nel Corso di Laurea in Fisioterapia
No full textLo scopo di questo studio è quello di analizzare i risultati ottenuti mediante l’analisi dei dati di un questionario
compilato dallo studente rispetto all’esperienza di tirocinio vissuta, con il preciso obiettivo di osservare i dati ottenuti
al fine di migliorare sia il processo di programmazione e pianificazione sia di verificare l’adeguatezza delle
sedi accreditate per l’esperienza clinica, nel rispetto e in coerenza con gli accordi stipulati in fase di convenzione.
Parole chiave: tirocinio professionalizzante, modelli di valutazione e di autovalutazione.
Summary
The purpose of this study is to examine student’s clinical perceptions of training experiences by the evaluation of a
questionnaire, in order to improve the clinical process and the planning of clinical teaching programme and quality.
Key words: professional training, evaluation and self-evaluation model
Position of nuclear medicine techniques in the diagnostic work-up of brain tumors
No full textAlthough any patient with a suspected brain tumor, either primary or metastatic, should be studied with anatomic imaging modalities such as angiography, computerized tomagraphy (CT) or magnetic resonance imaging (MRI), nuclear medicine techniques are available to further characterize some biological features of brain lesions and help in diagnosis and therapy planning. Bloob-brain-barrier disruption can be easily assessed with single-photon emission tomography (SPET), whereas focal metabolic changes can be better demonstrated by positron emission tomography (PET) as specific radiopharmaceuticals are available to detect changes in glucose utilization and aminoacid uptake with this technique. Expression of specific tumoral antigens is the basis of imaging with radioimmunoscintigraphy, a promising technique that can be applied to brain tumor therapy. The major clinical applications of nuclear medicine in the study of brain tumors -- evaluation of the extension of a tumoral mass, differential diagnosis and evaluation of therapy and prognosis -- are discussed
The Role of Mesothelin Expression in Serous Ovarian Carcinoma: Impacts on Diagnosis, Prognosis, and Therapeutic Targets
No full textMesothelin (MSLN) is a protein expressed in the mesothelial cell lining of the pleura,peritoneum, and pericardium; its biological functions in normal cells are still unknown. Experimental studies using knockout mice have suggested that this molecule does not play an important role in development and reproduction. In contrast, it has been observed that this molecule is produced in abnormal amounts in several malignant neoplasms, such as mesotheliomas and pancreatic adenocarcinomas. Many molecular studies have also demonstrated that mesothelin is overexpressed in HSOCs.
Here, we discuss the current knowledge of mesothelin and focus on its role in clinical and pathological diagnoses, as well as its impact on the prognosis of HSOC. Moreover, regarding the binding of MSLN to the ovarian cancer antigen CA125, which has been demonstrated in many studies, we also report on signal transduction pathways that may play an important role in the spread and neoplasticprogression of this lethal neoplasm. Given that mesothelin is overexpressed in many solid tumours and has antigenic properties, this molecule could be considered an antigenic target for the treatment of many malignancies. Consequently, we also review the literature to report on mesothelin-targeting therapies for HSOC that have been recently investigated in many clinical studies
A versatile algorithm for the treatment of open boundary conditions in Smoothed particle hydrodynamics GPU models
No full textAn open boundary algorithm for weakly compressible Smoothed particle hydrodynamics (WCSPH) numerical models is presented. Open boundary conditions are implemented by means of buffer regions whereby physical quantities are either imposed or extrapolated from the fluid region using a first-order accurate SPH interpolation. A unique formulation has been developed which can be used for inflow, outflow, and mixed open boundary conditions. The extrapolation process from the fluid domain encompasses quantities such as velocity, density, pressure and also free-surface elevation. The algorithm has been parallelized for both CPU and general-purpose on graphics processing units (GPGPU) and it has been tested against the 2-D reference solutions of flow past a cylinder and open channel flow. Finally, its capability to simulate 2-D and 3-D complex flows such as water waves and flow past a surface-piercing extraterrestrial submarine is demonstrated
Thermo-economic analysis of a low-cost greenhouse thermal solar plant with seasonal energy storage
No full textReduction of greenhouse gas emissions is today mandatory to limit the increase of ambient temperature. This paper provides a numerical study of a thermal solar plant using a seasonal dual-media sensible heat thermal energy storage system for supplying the total energy demand of a greenhouse located in the South of Italy, avoiding the use of the gas boiler. The aim of the work is to assess the technical and economic performance of a low-cost pit storage system, made of gravel and water, placed under the greenhouse to save surface. The study provides an original analysis of the charging and discharging phases during one year of operation on the basis of the real hourly heating demand and on real weather data. A sensitivity analysis of the levelized cost of heat is carried on with respect to the solar-collector area and to the storage-pit volume. The analysis shows that a minimum-cost design solution exists to cover 100% of the heat demand with an estimated levelized cost of heat of 153.3 EUR/MWh. The results demonstrate that dual-media thermal energy storage systems with solar thermal collectors represent a viable solution for reducing the environmental impact of greenhouses
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