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Showing 2 results for kafaee
Mohamad Ali kafaee, Atefeh Khosravi,
Volume 17, Issue 2 (Summer 2017 2017)
Abstract
Energy is one of the main production inputs, which indicates potential political and economic power in different countries. Due to higher energy prices, energy productivity is of special importance, and recent applied researches imply the effectiveness of energy productivity on economic growth. In addition, the process of regional economic growth is influenced by geographic conditions, regional and neighborhood specifications and functioning as well as usual regional economic variables including labor, capital, technology and energy. This paper estimates the effect of provincial energy productivity on provincial economic growth, using spatial econometric model and Maximum Likelihood method with applying provincial data from 2001 to 2011. In addition, it investigates β and σ convergence of energy productivity among Iran’s provinces. In spatial econometric method, we can consider the spillover effects and spatial relations among adjacent provinces with defining a distance-weight matrix between regions. Our findings indicate no σ convergence, but there is a conditional β convergence, which is a signal of existence of either spillover or neighborhood effect in provincial energy productivity growth. Meanwhile, the higher economic openness and lower government intervention in the economy improve energy productivity growth, but increasing energy price has no significant effect on the provincial energy productivity.
Volume 19, Issue 8 (August 2019)
Abstract
In this study, the mechanical properties of one of the most widely used polymeric biomaterials in the body called Poly Lactic Acid (PLA) in the porous state were evaluated. Firstly, the initial regular porous structures, based on the tetrahedron-catheter model known as Kelvin model, were designed for simulating bone tissue, using 3D design software with FDM technique. Afterwards, pressure test was used to determine the mechanical properties and mode of failure. Finally, experimental results were compared with the simulation software analysis results. The results showed that increasing the porosity reduces the strength and the increasing the cell size in a constant porosity results in increased compressive strength. Also, by decreasing the porosity, the amount of the strain up to fracture increases in a relatively constant stress. The brittle failure at 45° in the samples of high porosity was shown. However, the samples with a lower porosity had a relative ductile behavior and as the pressure rises, the cells accumulate on each other and change the form to the fracture point. Comparing the empirical and the simulation results showed that there is a good agreement between them and the simulation model has a high reliability for the porous model.
