Search results for "structural"

What are the relationships among Web 2.0, market orientation and innovativeness?

2013

PurposeFirms are adopting Web 2.0 technologies to improve collaboration, participation and communication; however there are few empirical studies testing the impact of this adoption. The purpose of this article is to analyze if there is a linkage amongst market orientation, Web 2.0 adoption and innovativeness.Design/methodology/approachStructural equation modeling was used to test the relationships amongst the variables. A sample of 244 firms of the hospitality industry was used. The theoretical approach is based on the market orientation and innovativeness, concepts, which have been studied by various authors in the literature.FindingsA positive relationship was found between market orient…

Expected principal stress directions under multiaxial random loading. Part I: theoretical aspects of the weight function method

1999

As has been observed experimentally by many authors, the position of the fatigue fracture plane appears to strongly depend on the directions of the principal stresses or strains. In Part I of the present work the expected principal stress directions under multiaxial random loading are theoretically obtained by averaging the instantaneous values of the three Euler angles through some suitable weight functions which are assumed to take into account the main factors influencing fatigue behaviour. Then, in Part II, it is examined how such theoretical principal directions determined by applying the proposed procedure are correlated to the position of the experimental fracture plane for some fati…

Fatigue fracture planes and expected principal stress directions under biaxial variable amplitude loading

2005

Fatigue behaviour under multiaxial variable amplitude loading can be examined by applying the failure criteria based on the critical plane approach. Positions of the critical plane can be determined in relation to the principal stress or strain directions. In the present paper, the expected directions of the principal stresses under proportional and non-proportional loading have been obtained by averaging the instantaneous values of the Euler angles through special weight functions. The known weight functions based on stress parameters appear not to be efficient for each loading or material being analysed. Thus, the authors consider new weight functions based on energy parameters. The prese…

Closure to "experimental Modeling of Submerged Pivot Weir" by M. Bijankhan and V. Ferro

2021

This paper is a Closure to “Experimental Modeling of Submerged Pivot Weir”.

Erratum for “Experimental Modeling of Submerged Pivot Weir” by M. Bijankhan and V. Ferro

2020

Interannual variability of rainfall in the eastern horn of Africa and indicators of atmospheric circulation

1993

Relationships between rainfall variations in the Eastern Horn of Africa, the Southern Oscillation, and the Indian Ocean temperature and pressure surface fields are studied for the period 1932–83. Rainfall data consist of stations and regional indices calculated for three selected areas experiencing quite different rainfall patterns. The results indicate significant negative correlations between northern autumn rains in Somalia and the Southern Oscillation during the same season. These rains are also negatively correlated with pressure in the Western Indian Ocean, and positively correlated in the Eastern Indian Ocean. The reverse pattern is shown with sea-surface temperature. This agrees ver…

Developing an economically advantageous wind forecasting method for electricity market design with a 15-minute imbalance settlement period

2019

According to legal framework developed by European Commission all EU Member States shall employ 15minute time resolution for imbalance settlement no later than 18th of December 2020 (or 1st of January 2025 in case of derogation). For intermittent energy sources that are traditionally associated with less precise generation forecasts this might result in considerable increase in imbalance costs. This presents a unique challenge for wind power station operators as there is lack of adequate forecasting tools supporting 15-minute time-resolution. The objective of this paper is to test and provide comparative analysis of alternative data interpolation methods in order to determine approach assoc…

Buckling strength of steel tube for lifting telescopic wind steel tower

2021

Abstract A telescopic pole for wind energy production with low environmental impact and its lifting system for a 60–250 kW turbine and a height of 30 m have been designed and manufactured. The tower, was raised and lowered by automation or by remote control, that allows one to differentiate the presence of the generator within the landscape over time. The jacking systems acting on the legs had a combination of holes (on the legs) and pegs actuated by hydraulic pistons. The aim of the paper was the experimental and the analytical verification of the stability condition of the steel piston as a lifting system of the prototype. An experimental investigation was carried out on small-scale speci…

Microtrichial patterns of the mesothoracic wing surface in Scutelleridae (Hemiptera)

2013

AbstractNew data on forewing microtrichial patterns are presented. Nineteen species representing 19 genera and seven subfamilies of Afrotropical Scutelleridae are investigated using scanning electron microscopy. Four types of microtrichial patterns are recognised. The taxonomic importance of these structures in the Scutelleridae is discussed.

Modelling of thermal stresses in bearing steel structure generated by electrical current impulses

2018

This work is the study of one particular candidate for white etching crack (WEC) initiation mechanism in wind turbine gearbox bearings: discharge current impulses flowing through bearing steel with associated thermal stresses and material fatigue. Using data/results from previously published works, the authors develop a series of models that are utilized to simulate these processes under various conditions/local microstructure configurations, as well as to verify the results of the previous numerical studies. Presented models show that the resulting stresses are several orders of magnitude below the fatigue limit/yield strength for the parameters used herein. Results and analysis of models …