Fatigue model for elastic bars in turbulent wind

Accumulated fatigue damage of an elastic structural bar vibrating in natural turbulent wind may be a primary cause of structural failure. Clumps of strong lateral oscillations may occur randomly with time. These oscillations are due to resonance between the vortex shedding frequency and the natural frequency of the bar. The so-called “lock in” phenomenon apparently extends resonance from a point of coincidence to an interval. An idealized stochastic model is set up on the basis of the empirically observed existence of a critical interval of undisturbed wind velocities upwind of the bar. The upwind velocities are modeled as realizations of a specific stochastic process. A clump of strong lateral, damped harmonic oscillations occurs during any uninterrupted “visit” of the velocity to the critical interval. For velocities outside the critical interval only insignificant lateral oscillations occur. The fatigue damage is assumed to be linearly accumulated according to the Palmgren—Miner rule within each clump and from clump to clump. The goal is to evaluate the structural reliability for any specified period of time. It is expressed in terms of a reliability index.     

Repertoire Contraction

The basic assumption of repertoire contraction is that only some of the logically closed subsets of the original belief set are viable as contraction outcomes. Contraction takes the form of choosing directly among these viable outcomes, rather than among cognitively more far-fetched objects such as possible worlds or maximal consistent subsets of the original belief set. In this first investigation of repertoire contraction, postulates for various variants of the operation are introduced. Necessary and sufficient conditions are given for when repertoire contraction coincides with AGM contraction or with operations generated by AGM-style contraction on a belief base. A close connection is shown to hold between repertoire contraction and specified meet contraction.     

Sorption Equilibrium in Relation to the Spatial Distribution of Molecules – Application to Desorption of Potato

ABSTRACT

An analysis of desarption isotherms for potato shows the following probable qualities in the water-potato sysarn. in the natural staa the walcr is bound rather strongly due to loss of rotational degrees of freedom in the sorbed molecules, which is caused by small molecular voids in the cellulose structure. This strucmre therefore is formcd as a uniformly cross bound state of the OH-groups. This slate prevails up to a cenin temperature, above which a reaction sas in. whcre OH bonds are successively braken, giving passibility for a panial rotation of sorbed molecules. in the range of lower moisture conlcnt the cellulose strucmre is changed into n crystalline slate a in wood, although the dcgrcc of crystallinity is lower, which is thc     

Properties of Calanus finmarchicus biomass during frozen storage after heat inactivation of autolytic enzymes

Calanus finmarchicus is a marine zooplankton of interest for the aquaculture industry, as well as for nutraceuticals and the cosmetic industry. The chemical composition of C. finmarchicus rapidly changes postmortem due to autolytic processes; in particular phospholipids rapidly degrade to give free fatty acids. The aim of this study was to inactivate autolytic enzymes in C. finmarchicus by applying heat (72 °C, 5-30 min) through mixing with boiling, fresh water, and further to explore the effects of heat (70 °C, 15 min) combined with long time storage (−20 °C, 12 months) of treated and untreated material. Heat treatment (5 min) inactivated all tested enzymes and maintained the initial amount of phospholipids, total lipids and crude protein. Storage of untreated material led to complete degradation of all phospholipids, whereas heat treatment resulted in a stable product containing the initial amount of phospholipids and astaxanthin.     

Phonemic fluency deficits in asymptomatic gene carriers for Huntington's disease.

The aim of the present study was to investigate verbal fluency in preclinical Huntington's disease (HD). Phonemic and semantic fluency and the rate of word production over time were assessed for 29 asymptomatic gene carriers and 34 noncarriers of HD. The relationship between fluency tasks and other cognitive domains was investigated. Compared to noncarriers, carriers produced fewer words and produced them more slowly in the phonemic fluency task but not in the semantic fluency task. When the carrier group was divided on the basis of Predicted-Years-To-Onset (PYTO), only carriers with     

Video-based Vibration Analysis by Modulated Projected Gratings

Abstract

We describe a time-averaging method for vibration analysis using white-light moiré technique and video recording. Phase modulation is used to obtain information on both the vibration amplitude and the vibration phase. The vibration fringe function is discussed for projection gratings. A method which makes it possible to reveal the amplitude and phase distribution by use of a digital image-processing system and phase-stepping technique is described. The results of implementing the method are shown.     

Production of enniatins A,A1, B,B1, B4, J1 by Fusarium tricinctum in solid corn culture: Structural analysis and effects on mitochondrial respiration

Enniatins (ENs) are secondary fungal metabolites with hexadepsipeptidic chemical structure and they possess a number of potent biological activities that can contaminate several kind of food and foodstuffs increasing the exposure risk for consumers. ENs are produced by several Fusariun strains including Fusarium subglutinans, Fusarium proliferatum and Fusarium tricinctum. Production of a mixture of ENs was performed by culturing F. tricinctum ITEM 9496 on white corn as substrate. The solid culture components were dried and subsequently extracted with water/methanol (50/50 v/v, 0.5% NaCl), homogenised, filtered, extracted by ethyl acetate and analysed by liquid chromatography with diode array detection (LC-DAD). The crude extract was first separated by low pressure liquid chromatography (LPLC) and then further purified by liquid chromatography (LC), resulting in six compounds with a purity higher than 95% as calculated by ¹H NMR, and with a yield of 30–300 mg per compound. The chemical structures of the ENs were determined by liquid chromatography coupled to mass spectrometry (LC–MS) and nuclear magnetic resonance (NMR). The biological activity of the resulting ENs was determined using a mitochondrial respiration test. We discovered that all the ENs studied induced an increase in the mitochondrial respiration resulting in uncoupling of the oxidative phosphorylation. This effect was most likely due to flux of K⁺ ions into the mitochondrial matrix. The order of potency of the ENs derivatives was: A₁ > B₁ > B > A > B₄ > J₁. These results suggest a correlation between the chemical structures and bioactivity and confirm the severe risks for human associated with consumption of enniatins.     

Non-Destructive Determination of the Structure and Composition of Glazes by Raman Spectroscopy

The utility of Raman spectroscopy as a non-destructive technique for the characterization of glassy (alumino)silicates (modern or ancient glazes and glasses) is demonstrated. The addition of fluxing ions breaks the Si–O linkages and the degree of (de)polymerization determines the relative intensity of the Si–O bending and stretching modes and hence the degree of polymerization could be classified. The analysis can be used to predict the processing temperature of glasses. Bending ( Q ^{' n} ) and stretching ( Qⁿ ) spectral components assigned to isolated ( Q ⁰ or SiO₄), and more or less connected SiO₄ vibrational units with one, two three/four bridging oxygen allow more precise analysis. The method is applied to reference modern porcelain glazes and selected ancient ceramic glazes and glasses, representative of the different production technologies used in the Asian, Islamic, and European worlds from Roman Empire to 19th century.     

Simulation of sea surface wave influence on small target detection with airborne laser depth sounding.

A theoretical model for simulation of airborne depth-sounding lidar is presented with the purpose of analyzing the influence from water surface waves on the ability to detect 1-m(3) targets placed on the sea bottom. Although water clarity is the main limitation, sea surface waves can significantly affect the detectability. The detection probability for a target at a 9-m depth can be above 90% at 1-m/s wind and below 80% at 6-m/s wind for the same water clarity. The simulation model contains both numerical and analytical components. Simulated data are compared with measured data and give realistic results for bottom depths between 3 and 10 m.