A Synthesis of Hybrid RANS/LES CFD Results for F-16XL Aircraft Aerodynamics

A synthesis is presented of recent numerical predictions for the F-16XL aircraft flow fields and aerodynamics. The computational results were all performed with hybrid RANS/LES formulations, with an emphasis on unsteady flows and subsequent aerodynamics, and results from five computational methods are included. The work was focused on one particular low-speed, high angle-of-attack flight test condition, and comparisons against flight-test data are included. This work represents the third coordinated effort using the F-16XL aircraft, and a unique flight-test data set, to advance our knowledge of slender airframe aerodynamics as well as our capability for predicting these aerodynamics with advanced CFD formulations. The prior efforts were identified as Cranked Arrow Wing Aerodynamics Project International, with the acronyms CAWAPI and CAWAPI-2. All information in this paper is in the public domain

Synthesis of Hybrid Computational Fluid Dynamics Results for F-16XL Aircraft Aerodynamics

A synthesis is presented of recent numerical predictions for the F-16XL aircraft flowfields and aerodynamics. The computational results were all performed with hybrid RANS/LES formulations, with an emphasis on unsteady flows and subsequent aerodynamics, and results from five computational methods are included. The work was focused on one particular low-speed, high angle-of-attack flight test condition, and comparisons against flight-test data are included. This work represents the third coordinated effort using the F-16XL aircraft, and a unique flight-test data set, to advance our knowledge of slender airframe aerodynamics as well as our capability for predicting these aerodynamics with advanced CFD formulations. The prior efforts were identified as Cranked Arrow Wing Aerodynamics Project International, with the acronyms CAWAPI and CAWAPI-2

Quasibrittle fracture scaling and size effect

The report attempts a broad review of the problem of size effect or scaling of failure, which has recently come to the forefront of attention because of its importance for concrete and geotechnical engineering, geomechanics, arctic ice engineering, as well as in designing large loadbearing parts made of advanced ceramics and composites, e.g. for aircraft or ships. First the main results of Weibull statistical theory of random strength are briefly summarized and its applicability and limitations described. In this theory as well as plasticity, elasticity with a strength limit, and linear elastic fracture mechanics (LEFM), the size effect is a simple power law because no characteristic size or length is present. Attention is then focused on the deterministic size effect in quasibrittle materials which, because of the existence of a non-negligible material length characterizing the size of the fracture process zone, represents the bridging between the simple powerlaw size effects of plasticity and of LEFM. The energetic theory of quasibrittle size effect in the bridging region is explained and then a host of recent refinements, extensions and ramifications are discussed. Comments on other types of size effect, including that which might be associated with the fractal geometry of fracture, are also made. The historical development of the size effect theories is outlined and the recent trends of research are emphasized

Quasibrittle fracture scaling and size effect

The report attempts a broad review of the problem of size effect or scaling of failure, which has recently come to the forefront of attention because of its importance for concrete and geotechnical engineering, geomechanics, arctic ice engineering, as well as in designing large loadbearing parts made of advanced ceramics and composites, e.g. for aircraft or ships. First the main results of Weibull statistical theory of random strength are briefly summarized and its applicability and limitations described. In this theory as well as plasticity, elasticity with a strength limit, and linear elastic fracture mechanics (LEFM), the size effect is a simple power law because no characteristic size or length is present. Attention is then focused on the deterministic size effect in quasibrittle materials which, because of the existence of a non-negligible material length characterizing the size of the fracture process zone, represents the bridging between the simple powerlaw size effects of plasticity and of LEFM. The energetic theory of quasibrittle size effect in the bridging region is explained and then a host of recent refinements, extensions and ramifications are discussed. Comments on other types of size effect, including that which might be associated with the fractal geometry of fracture, are also made. The historical development of the size effect theories is outlined and the recent trends of research are emphasized

Exciton-Exciton Annihilation as a Probe of Exciton Diffusion in Large Porphyrin Nanorings

The photophysical behavior of natural and artificial cyclic supramolecular structures has been intensively investigated in the past decade. Among the artificial structures, large fully π-conjugated porphyrin nanorings are of particular interest because of their electronic, structural, and topological features, which make them suitable candidates for light-harvesting applications. A number of factors affect the efficiency with which such structures harvest and transmit energy. For instance, under intense irradiation conditions, the efficiency of light harvesting can be quenched by competing processes, such as exciton–exciton annihilation. Here, we investigate the pump fluence dependence of the transient absorption spectra of a series of porphyrin nanorings ranging in circumference between 13 and 52 nm (10–40 porphyrin units). This allowed the isolation of a fluence-dependent fast-decaying component in all but the smallest nanorings studied. This effect has been assigned to exciton–exciton annihilation and fit to a one-dimensional exciton diffusion model, which confirms that the exciton size and/or its mobility are inversely proportional to the nanoring size

Research of working area development parameters in conditions of deep steep deposit finalizing

Отримано формули розрахунку об’єму запасів корисних копалин в приконтурній та глибинній зоні. Встановлено характер впливу параметрів доробки глибоких крутоспадних родовищ відкритим способом на доцільне положення поточних та проектних контурів кар’єру. Встановлено, що найменший середній коефіцієнт розкриву досягається при мінімальному значенні суми обсягів корисної копалини приконтурної зони лежачого і висячого боків покладу в проектному положенні. Найменший поточний коефіцієнт розкриву досягається при мінімальному значенні суми обсягів корисної копалини приконтурної зони лежачого і висячого боків покладу, а також робочого борту кар'єру в поточному положенні

Human Papillomavirus Genotype Distribution in Czech Women and Men with Diseases Etiologically Linked to HPV

The HPV prevalence and genotype distribution are important for the estimation of the impact of HPV-based cervical cancer screening and HPV vaccination on the incidence of diseases etiologically linked to HPVs. The HPV genotype distribution varies across different geographical regions. Therefore, we investigated the type-specific HPV prevalence in Czech women and men with anogenital diseases.We analyzed 157 squamous cell carcinoma samples, 695 precancerous lesion samples and 64 cervical, vulvar and anal condylomata acuminate samples. HPV detection and typing were performed by PCR with GP5+/6+ primers, reverse line blot assay and sequencing. samples. HPV types 6 and/or 11 were detected in 84% samples of condylomata acuminate samples.The prevalence of vaccinal and related HPV types in patients with HPV-associated diseases in the Czech Republic is very high. We may assume that the implementation of routine vaccination against HPV would greatly reduce the burden of HPV-associated diseases in the Czech Republic