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Experimental and Numerical Analysis of Cavity/Mean-Flow Interaction in Low Pressure Axial Flow Turbines

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Journal of Thermal Science 2021年第6期30卷 2178-2185页

作者： barsi dario COSTA Carlo LENGANI Davide SIMONI Daniele VENTURINO Giulio ZUNINO Pietro DIME-Universita di Genova Via Montallegro 11-16145 Genova

The increasing performance of modern aeroengines led the research towards the optimization of machine components not deeply analyzed in the *** this context,the mechanisms driving the interaction process between the secondary flows evolving at the hub of low-pressure turbines with the rotor-stator cavity systems have been poorly investigated in the *** this work,an experimental and numerical analysis of the interaction between the endwall near wall flow and the leakage flow of a real cavity system is *** experimental results were carried out in the annular low-pressure axial flow turbine of the University of *** blade loading and pressure distributions into the cavity,as well as the measured total pressure loss coefficient,have been used for a proper validation of CFD *** steady and unsteady calculations were carried out through the commercial solver ***,several numerical approaches have been tested into this work:RANS,Non Linear Harmonic(NLH),and *** most promising CFD techniques have been firstly identified by comparison with experimental results and then systematically employed to extend the analysis of secondary flow-cavity flow interaction to positions and quantities not available from the *** characterizing the mean flow-cavity flow interaction process will be shown to cover a great amount of the overall stage losses and should be properly accounted for the design of future optimized cavity configurations.

关键词： axial flow turbine cavity mean-flow interaction experimental analysis CFD

Compressor and Turbine Multidisciplinary Design for Highly Efficient Micro-gas Turbine

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Journal of Thermal Science 2018年第3期27卷 259-269页

作者： barsi dario PERRONE ANDrea QU Yonglei RATTO Luca RICCI Gianluca SERGEEV Vitaliy ZUNINO Pietro Department of Mechanical Energy Management and Transport Engineering Università degli Studi di Genova Faculty of Power and Energy Engineering Harbin Engineering University Institute of Energy and Transport Systems "Peter the Great" St. Petersburg Polytechnic University

Multidisciplinary design optimization （MDO） is widely employed to enhance turbomachinery compo- nents efficiency. The aim of this work is to describe a complete tool for the aero-mechanical design of a radial in- flow turbine and a centrifugal compressor. The high rotational speed of such machines and the high exhaust gas temperature （only for the turbine） expose blades to really high stresses and therefore the aerodynamics design has to be coupled with the mechanical one through an integrated procedure. The described approach employs a fuUy 3D Reynolds Averaged Navier-Stokes （RANS） solver for the aerodynamics and an open source Finite Element Analysis （FEA） solver for the mechanical integrity assessment. Due to the high computational cost of both these two solvers, a meta model, such as an artificial neural network （ANN）, is used to speed up the optimization design process. The interaction between two codes, the mesh genera- tion and the post processing of the results are achieved via in-house developed scripting modules. The obtained results are widely presented and discussed.

关键词： Micro-gas turbine Multidisciplinary Optimization Centrifugal Compressor Centripetal Turbine

Design of a Centrifugal Compressor for Micro Gas Turbine: Investigation of Scaling and Tip Clearance Effects

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Open Journal of Fluid Dynamics 2019年第1期9卷 49-62页

作者： dario barsi Alberto Bottino Andrea Perrone Luca Ratto Pietro Zunino Department of Mechanical Energy Management and Transportation Engineering University of Genova Genova Italy

The aim of this paper is to investigate the design in similarity of a centrifugal compressor for micro gas turbine and the related scaling effects on performance using CFD investigations. This work is part of a research project carried out by the Department DIME of the University of Genova, with the purpose of investigating the performance of a micro gas turbine in the change from 100 kW electrical output to 250 kW, while maintaining the compressor pressure ratio and geometry in similarity. The first part of the work focuses on the comparison between the original and the scaled machine, while the second part of the study deeply investigates the tip gap effect in the new configuration. The aim is to provide information about the performance of the compressor designed in geometrical similarity and to evaluate the tip gap height impact. From the efficiency point of view, the scaled-up machine has higher efficiency (up to 1.4% increment in design conditions) keeping the same technological limit for impeller manufacturing. However, the variation of tip gap height in the range 0 ÷ 1 mm strongly affects this parameter, leading to 10% alteration in design conditions between the ideal and worst case. The results, both in terms of overall performance and flow fields, are widely discussed in order to obtain simple yet reliable correlation for preliminary design.

关键词： Centrifugal Compressor Scaling Tip Gap CFD

Enhancing the light reactions of photosynthesis:Strategies,controversies,and perspectives

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Molecular Plant 2023年第1期16卷 4-22页

作者： dario Leister Plant Molecular Biology Faculty of BiologyLudwig-Maximilians-University(LMU)MunichMartinsried-PlaneggD-82152 MunichGermany

Photosynthesis is central to life on Earth,employing sunlight,water,and carbon dioxide to produce chemical energy and *** is generally accepted that boosting its efficiency offers one promising way to increase crop yields under agronomically realistic *** the components,structure,and regulatory mechanisms of the light reactions of photosynthesis are well understood,concepts for enhancing the process have been suggested and partially *** approaches vary in complexity,from targeting single components to comprehensive redesign of the whole process on the scales from single cells or tissues to whole *** to enhance light utilization per leaf,by decreasing pigmentation,increasing levels of photosynthetic proteins,prolonging the lifespan of the photosynthetic machinery,or massive reconfiguration of the photosynthetic machinery and the incorporation of nanomaterials,are discussed in this review ***,strategies intended to optimize the acclimation of photosynthesis to changes in the environment are presented,including redesigning mechanisms to dissipate excess excitation energy(e.g.,non-photochemical quenching)or reduction power(e.g.,flavodiiron proteins).Moreover,schemes for improving acclimation,inspired by natural or laboratory-induced adaptation,are ***,all these endeavors are still in an early exploratory phase and/or have not resulted in the desired outcome,largely because photosynthesis is embedded within large networks of closely interacting cellular and metabolic processes,which can vary among species and even *** explains why integrated,systems-wide approaches are required to achieve the breakthroughs required for effectively increasing crop yields.

关键词： Arabidopsis adaptive laboratory evolution crop yield photosynthesis synthetic biology tobacco

Single-particle resonances in a deformed relativistic potential

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Science China(Physics,Mechanics & Astronomy) 2010年第4期53卷 773-778页

作者： VRETENAR dario Physics Department Faculty of Science University of Zagreb Croatia

The positive-parity single-neutron levels in an axially-deformed relativistic quadrupole Woods-Saxon potential are analyzed. Neutron states are obtained as the solutions of the corresponding single-particle Dirac equation, using the coupled-channels method in the coordinate space. The evolution of the levels close to the continuum threshold and, in particular, the occurrence of singleneutron resonant states as the functions of the axial deformation parameter 0 β 0.5, are examined using the eigenphase representation. Calculations are performed for different values of the radius of the potential (R/r 0 ) 3 , corresponding to a variation of the mass number A.

关键词： single-particle resonance Dirac equation quadrupole deformation coupled-channels method

Microscopic analysis of spherical to γ-soft shape transitions in Zn isotopes

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Science China(Physics,Mechanics & Astronomy) 2011年第2期54卷 222-226页

作者： VRETENAR dario Physics Department Faculty of ScienceUniversity of Zagreb

The rapid transition between spherical and γ-soft shapes in Zn isotopes in the mass A 70 region,is analyzed using excitation spectra and collective wave functions obtained by diagonalization of a five-dimensional Hamiltonian for quadrupole vibrational and rotational degrees of freedom,with parameters determined by constrained self-consistent relativistic mean-field calculations for triaxial *** microscopic potential energy surfaces,together with the characteristic collective observables,illustrate a rapid transition from near spherical shape at the N = 40 subshell,to γ-soft deformed shapes for lighter *** calculated spectra display fingerprints of a second-order shape phase transition that can be approximately described by the E(5) analytic solution.

关键词： quantum phase transitions E(5) critical-point symmetry five-dimensional Hamiltonian

Standardizing and Centralizing Datasets for Efficient Training of Agricultural Deep Learning Models

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Plant Phenomics 2023年第4期5卷 689-702页

作者： Amogh Joshi dario Guevara Mason Earles Department of Viticulture and Enology University of CaliforniaDavisDavisCAUSA Department of Biological and Agricultural Engineering University of CaliforniaDavisDavisCAUSA AI Institute for Next-Generation Food Systems(AIFS) University of CaliforniaDavisDavisCAUSA

In recent years,deep learning models have become the standard for agricultural computer *** models are typically fine-tuned to agricultural tasks using model weights that were originally fit to more general,non-agricultural *** lack of agriculture-specific fine-tuning potentially increases training time and resource use,and decreases model performance,leading to an overall decrease in data *** overcome this limitation,we collect a wide range of existing public datasets for 3 distinct tasks,standardize them,and construct standard training and evaluation pipelines,providing us with a set of benchmarks and pretrained *** then conduct a number of experiments using methods that are commonly used in deep learning tasks but unexplored in their domain-specific applications for *** experiments guide us in developing a number of approaches to improve data efficiency when training agricultural deep learning models,without large-scale modifications to existing *** results demonstrate that even slight training modifications,such as using agricultural pretrained model weights,or adopting specific spatial augmentations into data processing pipelines,can considerably boost model performance and result in shorter convergence time,saving training ***,we find that even models trained on low-quality annotations can produce comparable levels of performance to their high-quality equivalents,suggesting that datasets with poor annotations can still be used for training,expanding the pool of currently available *** methods are broadly applicable throughout agricultural deep learning and present high potential for substantial data efficiency improvements.

关键词： weights overcome shorter

First Occurrence of Paragordius varius in Different Species of Acrididae in Irapuato, Guanajuato, Mexico

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Advances in Entomology 2025年第1期13卷 120-125页

作者： Manuel dario Salas-Araiza Ilse Alejandra Huerta-Arredondo Rafael Guzmán-Mendoza Itzel Berenice Aguilar-Campos Daniela de Jesús Bustos-Gallaga Miguel Angel Rocha-García David Isaías Rodríguez-Vázquez Agronomy Department Life Sciences Division University of Guanajuato Irapuato Mexico

Acridid populations have increased significantly in recent years, causing damage to crops. Having biocontrol tools is important as it will help reduce the use of insecticides. This study reports the presence of Paragordius varius in grasshoppers for the first time in Irapuato, Guanajuato, Mexico. Samples were taken from the grass around a water pond. A total of 1,225 grasshoppers were dissected to observe the presence of the worm. Seven species of grasshoppers were identified, with the most abundant species being Melanoplus differentialis. The parasitoid Paragordius varius, a nematomorph, parasitized male M. differentialis in greater numbers. This work is the first record of this parasitoid in Mexico and contributes to the knowledge of the biological control of acridids in Mexico.

关键词： Grasshoppers Paragordius varius Parasitism Nematomorph Biological Control

On the genetic distinctiveness of tailorbirds(Cisticolidae:Orthotomus)from the South-east Asian mainland with the description of a new subspecies

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Avian Research 2018年第3期9卷 214-225页

作者： Jerome Fuchs dario Zuccon Institut de Systématique EvolutionBiodiversitéUMR7205 CNRS MNHN UPMC EPHESorbonne UniversitéMuséum National d’Histoire NaturelleCP 5157 rue Cuvier75231 Paris Cedex 05France

Background: The Cambodian Tailorbird(Orthotomus chaktomuk) was one of the most recent major ornithological discoveries in South-east Asia as it originated from lowland seasonally flooded scrub within the densely inhabited floodplain around the Tonle Sap, Mekong and Bassac rivers(Cambodia). The Cambodian Tailorbird is sister to the Dark-necked Tailorbird(O. atrogularis) with very limited genetics and biometric differentiation. Between 2004 and 2012, evidences of a new population of Ashy Tailorbird(O. ruficeps) in SE Cambodia/Vietnam accumulated but no museum specimens were ever reported. The Ashy Tailorbird currently consists of eight subspecies among which the closest geographical populations, O. r. cineraceus(SE Burma to Malay Peninsula, Sumatra, Bangka and Belitung) and O. r. borneoensis(Borneo), are allopatric. Subspecific identification of the Cambodian Ashy Tailorbirds individuals was not possible because of the limited differences in plumage among ***: We inspected the Orthotomus ruficeps specimens housed at the Museum National d'Histoire Naturelle(Paris) and discovered five specimens of O. ruficeps collected by Louis Rodolphe Germain in ‘Cochinchina'(corresponding to southern Vietnam) during the nineteenth century. We sequenced one mitochondrial locus and gathered biometric data from these specimens and compared them with other Orthotomus ***: The Ashy Tailord population from SE Cambodia and Vietnam is distinct from the two geographically close subspecies O. r. borneoensis(1.7%) and O. r. cineraceus(1.3%). O. chaktomuk is nested within O. atrogularis in the mitochondrial gene tree. The SE Cambodia/Vietnam population of O. ruficeps is distinct from the two other subspecies in bill ***: Our study described the biometric and molecular distinctiveness of a recently re-discovered population of Ashy Tailord in SE Cambodia and Vietnam and suggests that this population constitutes an independent evolutionary lineage that we de

关键词： Orthotomus Differentiation Subspecies Taxonomy