Effect of the model’s geometry in fretting fatigue life prediction

This paper analyses the influence that the type of geometry used to obtain the stress/strain fields in a cylindrical contact has on fretting fatigue life predictions. In addition, this work considers the effect that the fatigue crack shape assumed has on these fretting fatigue life predictions. The strain/stress fields are calculated using a series of finite elements models that consider the following three types of behaviour: plane stress, plane strain (2D geometries) and 3D. Each of these models gives a different crack initiation life and a different evolution of the stress intensity factor (SIF), which are calculated using the weight function method. These models therefore provide different fretting fatigue life predictions. Finally, the lives obtained using the numerical models are compared with experimental lives

Comparison of two multiaxial fatigue models applied to dental implants

This paper presents two multiaxial fatigue life prediction models applied to a commercial dental implant. One model is called Variable Initiation Length Model and takes into account both the crack initiation and propagation phases. The second model combines the Theory of Critical Distance with a critical plane damage model to characterise the initiation and initial propagation of micro/meso cracks in the material. This paper discusses which material properties are necessary for the implementation of these models and how to obtain them in the laboratory from simple test specimens. It also describes the FE models developed for the stress/strain and stress intensity factor characterisation in the implant. The results of applying both life prediction models are compared with experimental results arising from the application of ISO-14801 standard to a commercial dental implan

Zinc nitride thin films: Basic properties and applications

A. Redondo-Cubero, M. Gómez-Castaño, C. García Núñez, M. Domínguez, L. Vázquez, J. L. Pau , "Zinc nitride thin films: basic properties and applications", Oxide-based Materials and Devices VIII, Proc. SPIE 10105, 101051B (24 February 2017); doi: 10.1117/12.2253044. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibitedProceedings of VIII Oxide-based Materials and Devices Conference (San Francisco, California, United States)Zinc nitride films can be deposited by radio frequency magnetron sputtering using a Zn target at substrate temperatures lower than 250°C. This low deposition temperature makes the material compatible with flexible substrates. The asgrown layers present a black color, polycrystalline structures, large conductivities, and large visible light absorption. Different studies have reported about the severe oxidation of the layers in ambient conditions. Different compositional, structural and optical characterization techniques have shown that the films turn into ZnO polycrystalline layers, showing visible transparency and semi-insulating properties after total transformation. The oxidation rate is fairly constant as a function of time and depends on environmental parameters such as relative humidity or temperature. Taking advantage of those properties, potential applications of zinc nitride films in environmental sensing have been studied in the recent years. This work reviews the state-of-the-art of the zinc nitride technology and the development of several devices such as humidity indicators, thin film (photo)transistors and sweat monitoring sensors.This research is supported by the MINECO (CTQ2014-53334-C2-2-R) and Comunidad de Madrid (NANOAVANSENS ref. S2013/MIT-3029). ARC acknowledges Ramón y Cajal program (under contract number RYC-2015-18047

Spatial and temporal distribution of Mycobacterium tuberculosis complex infection in Eurasian badger (Meles meles) and cattle in Asturias, Spain

Trabajo presentado al: 69th Wildlife Disease Association and 14th European Wildlife Disease Association Conference. Cuenca, Spain. p. 66. 31 agosto-2 septiembre

Information theory in the study of anisotropic radiation

Information theory is used to perform a thermodynamic study of non equilibrium anisotropic radiation. We limit our analysis to a second-order truncation of the moments, obtaining a distribution function which leads to a natural closure of the hierarchy of radiative transfer equations in the so-called variable Eddington factor scheme. Some Eddington factors appearing in the literature can be recovered as particular cases of our two-parameter Eddington factor. We focus our attention in the study of the thermodynamic properties of such systems and relate it to recent nonequilibrium thermodynamic theories. Finally we comment the possibility of introducing a nonequilibrium chemical potential for photons.Comment: 1 eps figure upon request by e-mail, to appear in Journal of Physics

Foot Pain and Morphofunctional Foot Disorders in Patients with Rheumatoid Arthritis: A Multicenter Cross-Sectional Study

[Abstract] Foot problems are highly prevalent in people with rheumatoid arthritis. This study aims to explore the foot morphology, pain and function in rheumatoid arthritis patients and the relation with the time of disease debut. A cross-sectional study was designed. Footprint, the Foot Posture Index, the hallux valgus prevalence, foot pain and function in 66 rheumatoid arthritis patients and the association with time since diagnosis, were recorded. The Foot Function Index, the Manchester Foot Pain and Disability Index, the Visual Analogic Scale, and the Manchester Scale for hallux valgus were administered and analyzed in two groups, with less and more than 10 years of diagnosis of the disease. A high prevalence of pronated (right 36.8% and left 38.6%) and highly pronated (right 15.8% and left 15.8%) feet was observed, as well as an elevated percentage of low arched footprints (right 68.4 and left 66.7%) and hallux valgus (right 59.6% and left 54.4%). Hallux valgus prevalence, toe deformities and Foot Function Index (Functional limitation) factors were significantly associated with the time since RA diagnosed adjusted for the other factors. The adjusted odds ratio of Hallux valgus prevalence was 4.9 (1.2–19.7). In addition, the foot function was diminished, and foot pain was present in most participants. In conclusion, rheumatoid arthritis patients’ feet showed altered morphology and function, and with longer rheumatoid arthritis history, metatarsophalangical stability and foot function, but not pain and global foot posture, were likely to deteriorat

Susceptibility of biological stages of the horn fly, Haematobia irritans, to entomopathogenic fungi (Hyphomycetes)

The susceptibility of the egg, pupa, and adult of Haematobia irritans (L.) (Diptera: Muscidae) to isolates of the fungi Metarhizium anisopliae (Metsch.) Sor., Beauveria bassiana (Bals.) Vuill., and Paecilomyces fumosoroseus (Wize) Brown and Smith, was evaluated under laboratory conditions. Groups of 20 eggs than 4 h old, pupae less than 48h old and adults were sprayed with a conidial suspension of each isolate. Eggs, pupae and adults of horn fly were susceptible to these entomopathogenic fungi. For treated eggs, the isolates Ma3, Ma 15, Ma25, Pfr1, and Pfr8 reduced adult emergence to 3.8% to 6.3% in comparison with the control (72%). The mortality of pupae infected by the isolates Ma2, Ma25, and Pfr10 ranged between 50% and 71.3%. Mortality of adults after treatment with the isolates Ma6, Ma 10, Ma 14, Ma 15, Pfr 1, Pfr 9, Pfr 10, Pfr 11, and Pfr12 were higher than 90%. The isolate Ma6 produced the lowest LC(50) against adult horn flies (8.08 &times 10(2)conidia/ml). These findings supported the hypotheses that isolates of M. anisopliae, and P. fumosoroseus are pathogenic against the different biological stages of horn flies by reducing adult emergence when applied on groups of eggs and pupae, and producing mortality when applied to adults

Understanding the Driving Mechanisms of Enhanced Luminescence Emission of Oligo(styryl)benzenes and Tri(styryl)-s-triazine

This work is focused on unraveling the mechanisms responsible for the aggregation-induced enhanced emission and solid-state luminescence enhancement effects observed in star-shaped molecules based on 1,3,5-tris(styryl)- benzene and tri(styryl)-s-triazine cores. To achieve this, the photophysical properties of this set of molecules were analyzed in three states: free molecules, molecular aggregates in solution, and the solid state. Different spectroscopy and microscopy experiments and DFT calculations were conducted to scrutinize the causative mechanisms of the luminescence enhancement phenomenon observed in some experimental conditions. Enhanced luminescence emission was interpreted in the context of short- and long-range excitonic coupling mechanisms and the restriction of intramolecular vibrations. Additionally, we found that the formation of pstacking aggregates could block E/Z photoisomerization through torsional motions between phenylene rings in the excited state, and hence, enhancing the luminescence of the syste