Search results for "equivalent"
showing 10 items of 308 documents
Fatigue fracture plane under Multiaxial Random Loadings - prediction by variance of equivalent stress based on the maximum shear and normal stresses
1992
It is assumed that the plane in which the maximum variance of the equivalent stress appears is critical for a material and the fatigue fracture should be expected in this plane. The equivalent stress is calculated according to the fatigue criterion of maximum shear and normal stresses in the fracture plane. It was demonstrated that for each stationary random stress state there is one or more critical planes where the fatigue fracture plane can be expected. The variance method together with the discussed fatigue criterion give good results for three analysed types of carbon steels under multiaxial cyclic loadings.
ESTIMATED AND EXPERIMENTAL FATIGUE LIVES OF 30CrNiMo8 STEEL UNDER IN-AND OUT-OF-PHASE COMBINED BENDING AND TORSION WITH VARIABLE AMPLITUDES
2007
Abstract— Calculated fatigue lives, based on three criteria for multiaxial random fatigue, were compared with lives obtained from tests on cylindrical specimens of 30CrNiMo8 steel subjected to in- and out-of-phase bending and torsion at variable amplitudes. In the chosen fatigue criteria the expected position of the fracture plane, determined from a variance method for the equivalent stress, were taken into account. The equivalent stress history was related to the rain flow method and fatigue damage was evaluated from the Palmgren–Miner hypothesis. It has been shown that the expected fatigue fracture planes agree with those determined by experiments. The most realistic estimations of fatigu…
The impact of intercellular communication for the generation of complex multicellular prevascularized tissue equivalents
2019
In reconstructive surgery the use of prevascularized soft tissue equivalents is a promising approach for wound coverage of defects after tumor resection or trauma. However, in previous studies to generate soft tissue equivalents on collagen membranes, microcapillaries were restricted to superficial areas. In this study, to understand which factors were involved in the formation of these microcapillaries, the levels of the angiogenic factors vascular endothelial growth factor (VEGF), Interleukin-8 (IL-8), and basic fibroblast growth factor (bFGF) in the supernatants of the tissue equivalents were examined at various time points and conditions. Additionally, the influence of these factors on …
Long-Term Administration of High Dose Vitamin A to Rats Does Not Cause Fetal Malformations: Macroscopic, Skeletal and Physicochemical Finds
1996
A rat model was used to investigate whether high oral doses of vitamin A lead to fetal malformations and to what extent retinyl esters (RES) are transferred from the mother to the fetuses. Retinol and RES concentrations in plasma behave similarly in rats and humans. When high concentrations of vitamin A are administered, plasma retinol concentrations remain relatively constant, whereas plasma RES increased in parallel with the dose. To achieve an elevation from approximately 150 to > 1525 nmol x L(-1) in the experimental group before mating, female Ibm: RORO (spf) rats were fed a maintenance diet enriched with 15.2 x 10(3) retinol equivalents (RE) x kg(-1) at the start and increased stepwis…
Vitamin C, vitamin A, phenolic compounds and total antioxidant capacity of new fruit juice and skim milk mixture beverages marketed in Spain
2007
Abstract The growing interest in new functional foods with special characteristics and health properties has led to the development of new beverages based on fruit juice–skim milk mixtures. The proliferation of ready-to-drink beverages has caused the market to focus its interest on these products. Commercial conventionally pasteurized or sterilized beverages based on a mixture of fruit juice and skim milk were evaluated nutritionally for their concentrations of vitamin C, vitamin A and phenolic compounds and their total antioxidant capacity, taking the influence of physicochemical parameters into account. The main contribution to the total antioxidant capacity (TEAC, trolox equivalent antio…
Oxidative stress and antioxidant status in beta-thalassemia major: iron overload and depletion of lipid-soluble antioxidants
1996
Because of continuous blood transfusions, thalassemia patients are subjected to peroxidative tissue injury by the secondary iron overload. In accordance, analysis of serum from 42 beta-thalassemia patients, aged 4 to 40 years, showed that the mean concentrations of conjugated diene lipid hydroperoxides (CD), lipoperoxides evaluated as malondialdehyde/ thiobarbituric acid (MDA/TBA) adducts, and protein carbonyls increased about twofold with respect to control. Ferritin levels were positively correlated with the amount of MDA (r = .41; P = .007) and showed a positive trend with CD (r = .31; P = .07) and protein carbonyls (r = .35; P = .054), as further evidence of the deleterious effects of h…
Rapid laccolith intrusion driven by explosive volcanic eruption
2016
Magmatic intrusions and volcanic eruptions are intimately related phenomena. Shallow magma intrusion builds subsurface reservoirs that are drained by volcanic eruptions. Thus, the long-held view is that intrusions must precede and feed eruptions. Here we show that explosive eruptions can also cause magma intrusion. We provide an account of a rapidly emplaced laccolith during the 2011 rhyolite eruption of Cordón Caulle, Chile. Remote sensing indicates that an intrusion began after eruption onset and caused severe (>200 m) uplift over 1 month. Digital terrain models resolve a laccolith-shaped body ∼0.8 km3. Deformation and conduit flow models indicate laccolith depths of only ∼20–200 m and ov…
Comportamento di una passerella pedonale strallata nei confronti delle azioni del vento
2007
The wind behaviour of a stayed footbridge has been analyzed. In order to avoid aeroelastic phenomena, an experimental campaign on a 1:15 scale model has been realized at the boundary-layer wind-tunnel of the Milan Polytechnic. The aerodynamic characterization of the structure has allowed to direct the project towards the choice of non-solid barriers, but with a medium porosity, by avoiding possible problems that can lead to ultimate limit state condi-tions of the structure (e.g., flutter or vortex shedding). In this way the quantitative effect of barriers has been estimated deducing reliable values not only for the alongwind forces, but also for the crosswind and torsional actions.
Polish Americans in the History of Bilingual Lexicography: The State of the Art
2018
This paper measures dictionaries made by Polish Americans against the development of the Polish–English and English–Polish lexicographic tradition. Of twenty nine monoscopal and biscopal glossaries and dictionaries published between 1788 and 1947, four may be treated as mile-stones: Erazm Rykaczewski's (1849–1851), Władysław Kierst and Oskar Callier's (1895), Władysław Kierst's (1926–1928), and Jan Stanisławski's (1929). Unsurprisingly, they came to be widely repub-lished in English-speaking countries, primarily the United States of America, for the sake of Polish-speaking immigrants. One might therefore wonder whether there was any pressing need for new dictionaries. There must have been, …
Modeling by the finite element method of acoustic radiation in waveguides lined with locally or non locally reacting absorbent materials in the prese…
2011
Our concern in this work is the problem of acoustic propagation in guides lined with locally or non locally reacting materials with the presence of mean fluid flow. In several industrial systems such as aircraft jet engines, mufflers exhaust and ventilation systems, noise is mostly channeled outside by guides of more or less complex geometries. A study of waveguides makes it possible to predict and understand the physical phenomena such as refraction, convection, absorption and wave attenuation. In waveguides studies, guides are often considered infinitely long to get rid of some phenomena (reflection for example) at their ends. Solving the problem of acoustic propagation in infinite guides…