Fatigue crack-growth rate in ferrite martensite dual-phase steel

An empirical study is made on the fatigue crack growth rate in ferrite-martensite dual-phase (FMDP) steel. Particular attention is given to the effect of ferrite content in the range of 24.2% to 41.5% where good fatigue resistance was found at 33.8%. Variations in ferrite content did not affect the crack growth rate when plotted against the effective stress intensity factor range  which was assumed to follow a linear relation with the crack tip stress intensity factor range ΔK. A high  corresponds to uniformly distributed small size ferrite and martensite. No other appreciable correlation could be ralated to the microstructure morphology of the FMDP steel. The closure stress intensity factor , however, is affected by the ferrite content with  reaching a maximum value of 0.7. In general, crack growth followed the interphase between the martensite and ferrite.

Dividing the fatigue crack growth process into Stage I and II where the former would be highly sensitive to changes in ΔK and the latter would increase with ΔK depending on the  ratio. The same data when correlated with the strain energy density factor range ΔS showed negligible dependence on mean stress or R ratio for Stage I crack growth. A parameter α involving the ratio of ultimate stress to yield stress, percent reduction of area and R is introduced for Stage II crack growth so that the  data for different R would collapse onto a single curve with a narrow scatter band when plotted against αΔS.

El análisis del entorno político y legal en el marco de la planificación estratégica en el sector turístico y hotelero

[ES] Las empresas turísticas se encuentran inmersas en un entorno cambiante, caracterizado por los avances tecnológicos, al aumento de la competencia global y a las consecuencias derivadas de la crisis económica mundial. Ante estas circunstancias, las empresas turísticas se ven obligadas a diseñar estrategias de marketing y llevar a cabo planes estratégicos. Pues bien, para entender el marketing y desarrollar estrategias eficaces, es fundamental entender el contexto en el que opera la empresa, puesto que en él se generan las oportunidades del mercado y se presentan las amenazas que van a condicionar su futuro. Entre las fuerzas que integran el entorno empresarial se encuentran la economía, la sociedad, la política o la demografía, entre otras.

Tax-Based Fisheries Management: The Case Study Of The Cantabrian Anchovy Fishery

A dynamic optimisation framework is adopted to show how tax-based management systems theoretically correct the inefficient allocation of fishing resources derived from the stock externality. Optimal Pigouvian taxes on output (τ) and on inputs (γ) are calculated, compared and considered as potential alternatives to the current regulation of VIII division Cantabrian anchovy fishery. The sensibility analysis of optimal taxes illustrates an asymmetry between (τ) and (γ) when cost price ratio varies. The distributional effects also differ. Special attention will be paid to the real implementation of the tax-based systems in fisheries.