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Transition Modelling with the k-Ω Turbulence Model and an Intermittency Transport Equation

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Journal of Thermal Science 2004年第3期13卷 220-225页

作者： Koen LODEFIER bart merci Chris De LANGHE Erik DICK Ghent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent BelgiumGhent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent BelgiumGhent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent BelgiumGhent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent Belgium

In gas turbine engines, laminar-turbulent transition occurs. However, generally, the turbulence models to describe such transition results in too early and too short transition. Combining a turbulence model with a description of intermittency, i.e. the fraction of time the flow is turbulent during the transition phase, can improve it. By letting grow the intermittency from zero to unity, start and evolution of transition can be imposed. In this paper, a method where a dynamic equation of intermittency combining with a two-equation k-ωturbulence model is described. This intermittency factor is a premultiplicator of the turbulent viscosity computed by the turbulence model. Following a suggestion by Menter et al.[1], the start of transition is computed based on local variables.

关键词： bypass transition intermittency SST turbulence model.

VLES Modelling with the Renormalization Group

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Journal of Thermal Science 2003年第4期12卷 328-331页

作者： Chris De Langhe rug.ac.be bart merci rug.ac.be Koen Lodefier rug.ac.be Erik Dick rug.ac.be Ghent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent Belgium

In a Very-Large-Eddy Simulation (VLES), the filterwidth-wavenumber can be outside the inertial range, and simple subgrid models have to be replaced by more complicated (''RANS-like'') models which can describe the transport of the biggest eddies. One could approach this by using a RANS model in these regions, and modify the lengthscale in the model for the LES-regions. The problem with these approaches is that these models are specifically calibrated for RANS computations, and therefore not suitable to describe inertial range quantities. We investigated the construction of subgfid viscosity and transport equations without any calibrated constants, but these are calculated directly form the Navier-Stokes equation by means of a Renormalization Group (RG) procedure. This leads to filterwidth dependent transport equations and effective viscosity with the right limiting behaviour (DNS and RANS limits).

关键词： very-large-eddy simulation subgrid modellig k-εmodel.

Generating synthetic as-built additive manufacturing surface topography using progressive growing generative adversarial networks

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Friction 2024年第6期12卷 1283-1298页

作者： Junhyeon SEO Prahalada RAO bart RAEYMAEKERS Department of Mechanical Engineering Virginia TechBlacksburgVA 24061USA Grado Department of Industrial and Systems Engineering Virginia TechBlacksburgVA 24061USA

Numerically generating synthetic surface topography that closely resembles the features and characteristics of experimental surface topography measurements reduces the need to perform these intricate and costly ***,existing algorithms to numerically generated surface topography are not well-suited to create the specific characteristics and geometric features of as-built surfaces that result from laser powder bed fusion(LPBF),such as partially melted metal particles,porosity,laser scan lines,and ***,we present a method to generate synthetic as-built LPBF surface topography maps using a progressively growing generative adversarial *** qualitatively and quantitatively demonstrate good agreement between synthetic and experimental as-built LPBF surface topography maps using areal and deterministic surface topography parameters,radially averaged power spectral density,and material ratio *** ability to accurately generate synthetic as-built LPBF surface topography maps reduces the experimental burden of performing a large number of surface topography ***,it facilitates combining experimental measurements with synthetic surface topography maps to create large data-sets that facilitate,*** as-built surface topography to LPBF process parameters,or implementing digital surface twins to monitor complex end-use LPBF parts,amongst other applications.

关键词： additive manufacturing surface topography synthetic surface topography generative adversarial networks

Guest editorial:Special Issue on Artificial Intelligence and Emerging Computational Approaches for Tribology

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Friction 2024年第6期12卷 1057-1059页

作者： Zhinan ZHANG Shuaihang PAN bart RAEYMAEKERS State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical Engineering University of UtahSalt Lake CityUT 84112USA Department of Mechanical Engineering Virginia TechBlacksburgVA 24061USA

Tribo-behavior is a complex system-based time-dependent process,and it is difficult to accurately model a tribo-system and predict its ***,tribology research,in most cases,has relied on extensive *** by the artificial intelligence(AI)-for-science revolution,AI and other emerging computational approaches provide opportunities to explore the complex processes in tribo-systems and the physical mechanisms of tribo-behavior in an efficient way,significantly pushing the boundaries of tribology research.

关键词： behavior editorial artificial

Numerical modeling techniques for noise emission of free railway wheels

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Railway Engineering Science 2024年第2期32卷 144-161页

作者： Linus Taenzer Urs Pachale bart Van Damme Andrea Bergamini Domenico Tallarico Laboratory of Acoustics/Noise Control EmpaÜberlandstrasse 129DübendorfSwitzerland

In this article,we consider the numerical prediction of the noise emission from a wheelset in laboratory *** focus on the fluid-structure interaction leading to sound emission in the fluid domain by analyzing three different methods to account for acoustic *** are a discretized baffled piston using the discrete calculation method(DCM),a closed cylindrical volume using the boundary element method(BEM)and radiating elastic disks in a cubic enclosure solved with the finite element method(FEM).We provide the validation of the baffled piston and the BEM using measurements of the noise emission of a railway wheel by considering ground reflections in the numerical *** space-resolved waveforms are compared with experimental results as well as with a fluid-structure interaction finite element *** computational advantage of a discretized disk mounted on a baffle and BEM compared to FEM is highlighted,and the baffled pistons limitations caused by a lack of edge radiation effects are investigated.

关键词： Discretized baffled piston Finite element Boundary element Railway noise Acoustic emission Vibrations

Tree species identity and interaction determine vertical forest structure in young planted forests measured by terrestrial laser scanning

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Forest Ecosystems 2024年第3期11卷 266-275页

作者： Mengxi Wang Lander Baeten Frieke Van Coillie Kim Calders Kris Verheyen Quentin Ponette Haben Blondeel bart Muys John Armston Hans Verbeeck Q-ForestLab Department of EnvironmentFaculty of Bioscience EngineeringGhent UniversityBelgium Forest&Nature Lab Department of EnvironmentFaculty of Bioscience EngineeringGhent UniversityBelgium Earth and Life Institute Université Catholique de Louvain(UCLouvain)Louvain-la-NeuveBelgium Department of Earth&Environmental Sciences KU LeuvenBelgium Department of Geographical Sciences University of MarylandCollege ParkMDUSA

Vertical forest structure is closely linked to multiple ecosystem characteristics,such as biodiversity,habitat,and *** tree species in planted forests has the potential to create diverse vertical forest structures due to the different physiological and morphological traits of the composing tree ***,the relative importance of species richness,species identity and species interactions for the variation in vertical forest structure remains unclear,mainly because traditional forest inventories do not observe vertical stand structure in *** laser scanning(TLS),however,allows to study vertical forest structure in an unprecedented ***,we used TLS single scan data from 126 plots across three experimental planted forests of a largescale tree diversity experiment in Belgium to study the drivers of vertical forest *** plots were 9–11years old young pure and mixed forests,characterized by four levels of tree species richness ranging from monocultures to four-species mixtures,across twenty composition *** generated vertical plant profiles from the TLS data and derived six stand structural *** mixed models were used to test the effect of species richness on structural *** a hierarchical diversity interaction modelling framework,we further assessed species identity effect and various species interaction effects on the six stand structural *** results showed that species richness did not significantly influence most of the stand structure variables,except for canopy height and foliage height *** identity on the other hand exhibited a significant impact on vertical forest structure across all *** interaction effects were observed to be site-dependent due to varying site conditions and species pools,and rapidly growing tree species tend to dominate these ***,our results highlighted the importance of considering both species identity an

关键词： TreeDivNet FORBIO Stand structural complexity Terrestrial laser scanning Vertical forest structure Tree diversity Planted forests

The Role of Age as a Risk Factor for Pickleball-Related Injuries

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Health 2024年第1期16卷 87-91页

作者： Ches Jones bart Hammig Department of Health Human Performance and Recreation University of Arkansas Fayetteville USA

Pickleball is a popular sport that includes players from many different demographics. The popularity has resulted in not only increases in participation but also in activity related injuries. The purpose of this study was to identify risk factors along with potential mechanisms for injuries related to pickleball and identify effective countermeasures. Methods included the identification of pickleball related injuries from a US National Emergency Room database (NEISS). A narrative section of the database was used to identify and categorize potential mechanisms of injury. Results indicated that the types and mechanisms of injury relate to three specific age groups: younger, middle age, and older players. Injuries to younger players under the age of 26 are likely the result of misuse of sport equipment. Middle aged players from 26 to 50 sustained injuries more related activity overuse. However, there were more concerns with players over 50 years of age with a great percentage resulting in cardia arrest or symptoms leading to more severe cardiovascular conditions. While pickleball activity should be encouraged as it is a beneficial form of physical activity, there should be specific age-group interventions to reduce injury. It should be highly recommended that doctors approve the activity for individual at risk for heart conditions and supervision for adults in that age group.

关键词： Physical Activity Cardiac Arrest Epidemiology Pickleball Injury

Inflammatory myofibroblastic tumor from molecular diagnostics to current treatment

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Oncology Research 2024年第7期32卷 1141-1162页

作者： PAULINA CHMIEL ALEKSANDRA SŁOWIKOWSKA ŁUKASZ BANASZEK ANNA SZUMERA-CIEĆKIEWICZ bartŁOMIEJ SZOSTAKOWSKI MATEUSZ J.SPAŁEK TOMASZŚWITAJ PIOTR RUTKOWSKI ANNA M.CZARNECKA Department of Soft Tissue/Bone Sarcoma and Melanoma Maria Sklodowska-Curie National Research Institute of OncologyWarsaw02-781Poland Faculty of Medicine Medical University of WarsawWarsaw02-091Poland Department of Pathology Maria Sklodowska Curie National Research Institute of OncologyWarsaw02-781Poland Department of Radiotherapy Maria Sklodowska-Curie National Research Institute of OncologyWarsaw02-781Poland

Inﬂammatory myoﬁbroblastic tumor(IMT)is a rare neoplasm with intermediate malignancy characterized by a propensity for recurrence but a low metastatic *** challenges arise from the diverse pathological presentation,variable symptomatology,and lack of different imaging ***,IMT is identiﬁed by the fusion of the anaplastic lymphoma kinase(ALK)gene,which is present in approximately 70%of cases,with various fusion partners,including ran-binding protein 2(RANBP2),which allows conﬁrmation of the *** surgery is the preferred approach for localized tumors,the optimal long-term treatment for advanced or metastatic disease is difﬁcult to deﬁ*** therapies are crucial for achieving sustained response to treatment within the context of genetic alteration in ***,an ALK tyrosine kinase inhibitor(TKI),was ofﬁcially approved by the US Food and Drug Administration(FDA)in 2020 to treat IMT with ALK ***,most patients face resistance and disease progression,requiring consideration of sequential *** radiotherapy with targeted therapy appears to be beneﬁcial in this *** promising results have also been achieved with immunotherapy,indicating potential for combined therapy ***,deﬁned recommendations are still *** review analyzes the available research on IMT,including genetic disorders and their impact on the course of the disease,data on the latest targeted therapy regimens and the possibility of developing immunotherapy in this indication,as well as summarizing general knowledge about prognostic and predictive factors,also in terms of resistance to systemic therapy.

关键词： Inﬂammatory myoﬁbroblastic tumor(IMT) Epithelioid inﬂammatory myoﬁbroblastic sarcoma Tyrosine kinase inhibitors(TKI) Anaplastic lymphoma kinase(ALK)

Intraoperative application of three-dimensional printed guides in total hip arthroplasty: A systematic review

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World Journal of Orthopedics 2024年第7期15卷 660-667页

作者： Tim P Crone bart M W Cornelissen Jakob Van Oldenrijk Pieter Koen Bos Ewout S Veltman Department of Orthopedic Surgery and Sports Medicine Erasmus Medical CenterRotterdam 3015 GDNetherlands Department of Oral and Maxillofacial Surgery Erasmus Medical CenterRotterdam 3015 GDNetherlands

BACKGROUND Acetabular component positioning in total hip arthroplasty(THA)is of key importance to ensure satisfactory post-operative outcomes and to minimize the risk of *** majority of acetabular components are aligned freehand,without the use of navigation *** specific instruments(PSI)and three-dimensional(3D)printing of THA placement guides are increasingly used in primary THA to ensure optimal *** To summarize the literature on 3D printing in THA and how they improve acetabular component *** PubMed was used to identify and access scientific studies reporting on different 3D printing methods used in *** studies with 236 hips in 228 patients were *** studies could be divided into two main categories;3D printed models and 3D printed *** 3D printing in THA helped improve preoperative cup size planning and post-operative Harris hip scores between intervention and control groups(P=0.019,P=0.009).Otherwise,outcome measures were heterogeneous and thus difficult to *** overarching consensus between the studies is that the use of 3D guidance tools can assist in improving THA cup positioning and reduce the need for revision THA and the associated *** The implementation of 3D printing and PSI for primary THA can significantly improve the positioning accuracy of the acetabular cup component and reduce the number of complications caused by malpositioning.

关键词： Total hip arthroplasty Three-dimensional printing Hip replacement surgery Three-dimensional planning Surgical guides