Search results for " STRESS"
showing 10 items of 3936 documents
Latvijas Republikas nozīmes pilsētu fiskālā stāvokļa novērtējums 2008.-2017. gadā
2019
Nereti iemesls valsts ekonomiskajai krīzei ir pašvaldību finansiālās problēmas. Tomēr lielākajā daļā Eiropas valstu, arī Latvijā, pašvaldību fiskālā stāvokļa novērtēšana netiek tik strikti veikta un regulēta kā tas notiek nacionālā līmenī. Darba mērķis ir noskaidrot, kāds ir deviņu Latvijas republikas nozīmes pilsētu fiskālais stāvoklis no 2008. līdz 2017. gadam, izmantojot fiskālā stāvokļa testus. Tiek veikta arī fiskālā stāvokļa prognozēšana, ņemot vērā sociālekonomisko, tostarp, demogrāfisko, faktoru tendences. Pētījuma rezultāti norāda, ka republikas nozīmes pilsētu fiskālais stāvoklis ir atšķirīgs – sastopama gan fiskālā veselība, gan fiskālais stress.
Experimental analysis of the effect of vegetation on flow and bed shear stress distribution in high-curvature bends
2016
The cross-sectional circulation, which develops in meandering bends, exerts an important role in velocity and the boundary shear stress redistributions. This paper considers the effect of vegetation on cross-sectional flow and bed shear distribution along a high-curvature bend. The analysis is conducted with the aid of data collected in a large-amplitude meandering flume during a reference experiment without vegetation and an experiment with vegetation on the bed. The results show that the presence of vegetation modifies the curvature-induced flow pattern and the directionality of turbulent structures. In fact, in the presence of vegetation, the turbulent structures tend to develop within a…
Effects of irregular two-dimensional and three-dimensional surface roughness in turbulent channel flows
2012
Abstract Wall-resolved Large Eddy Simulation of fully developed turbulent channel flows over two different rough surfaces is performed to investigate on the effects of irregular 2D and 3D roughness on the turbulence. The two geometries are obtained through the superimposition of sinusoidal functions having random amplitudes and different wave lengths. In the 2D configuration the irregular shape in the longitudinal direction is replicated in the transverse one, while in the 3D case the sinusoidal functions are generated both in streamwise and spanwise directions. Both channel walls are roughened in such a way as to obtain surfaces with statistically equivalent roughness height, but different…
Momentum transport and bed shear stress distribution in a meandering bend: Experimental analysis in a laboratory flume
2015
The paper concerns the mechanisms underlying the distribution of the bed shear stress in meandering bends. Literature indicates that cross-stream circulation strongly affects the redistribution of the downstream velocity, but the feedback between them is still poorly understood. The aim of this paper is to gain some insight into how the momentum transport by cross-stream circulation contributes to the bed shear stress redistribution. Experimental analysis, based on a detailed dataset collected in a large-amplitude meandering laboratory flume, is presented. From these data an evaluation is made of the terms in the depth-averaged momentum equations and the analysis is especially devoted to te…
The impact of dehydration rate on the production and cellular location of reactive oxygen species in an aquatic moss.
2012
† Background and Aims The aquatic moss Fontinalis antipyretica requires a slow rate of dehydration to survive a desiccation event. The present work examined whether differences in the dehydration rate resulted in corresponding differences in the production of reactive oxygen species (ROS) and therefore in the amount of cell damage. † Methods Intracellular ROS production by the aquatic moss was assessed with confocal laser microscopy and the ROS-specific chemical probe 2,7-dichlorodihydrofluorescein diacetate. The production of hydrogen peroxide was also quantified and its cellular location was assessed. † Key Results The rehydration of slowly dried cells was associated with lower ROS produc…
Mind the gap—deficits in our knowledge of aspects impacting the bioavailability of phytochemicals and their metabolites—a position paper focusing on …
2015
This is an open access article under the terms of the Creative Commons Attribution-Non-Commercial-NoDerivs Licence.-- et al.
Ammonium formate-Pd/C as a new reducing system for 1,2,4-oxadiazoles. Synthesis of guanidine derivatives and reductive rearrangement to quinazolin-4-…
2021
1,2,4-Oxadiazole is a heterocycle with wide reactivity and many useful applications. The reactive O-N bond is usually reduced using molecular hydrogen to obtain amidine derivatives. NH4CO2H-Pd/C is here demonstrated as a new system for the O-N reduction, allowing us to obtain differently substituted acylamidine, acylguanidine and diacylguanidine derivatives. The proposed system is also effective for the achievement of a reductive rearrangement of 5-(2′-aminophenyl)-1,2,4-oxadiazoles into 1-alkylquinazolin-4(1H)-ones. The alkaloid glycosine was also obtained with this method. The obtained compounds were preliminarily tested for their biological activity in terms of their cytotoxicity, induce…
Non-Local Thermoelasticity: The Fractional Heat conduction
2011
Mechanism of brittle fracture in a ductile 316 alloy during stress corrosion
1990
Abstract The ductile f.c.c. 316 alloy is shown to exhibit brittle transgranular (and intergranular) stress corrosion cracking in a 153°C MgCl2 solution at free corrosion potential. Tests on smooth and pre-cracked specimens are performed to identify the mechanisms of fracture. Transgranular cracking is related to both a discontinuous microcleavage mainly on {100} planes and a microshearing on {111} planes. A new physical modelization is proposed to explain the brittle transgranular cracking. It is based on the influence of the localized anodic dissolution on the enhancement of the plasticity at the crack tip. The formation of dislocation pile-ups and the conditions of restricted slip induce …