Morphological instability induced by the interaction of a particle with a solidifying interface

We show that the interaction of a particle with a directionally solidified interface induces the onset of morphological instability provided that the particle-interface distance falls below a critical value. This instability occurs at pulling velocities that are below the threshold for the onset of the Mullins-Sekerka instability. The expression for the critical distance reveals that this instability is manifested only for certain combinations of the physical and processing parameters. Its occurence is attributed to the reversal of the thermal gradient in the melt ahead of the interface and behind the particle.Comment: 5 pages, 4 figures. To appear in Eur. Phys. J.

The Qur’anic Idea of Peace

Peace is a chief social value, which the Qur’an appreciates, along with social justice, and submission to God and worshiping Him. War is initially an implausible situation, which should be invoked only when necessary. Hence, the rule is peace, and war is the exception. Using Muhammad Hussein Tabatabai’s methodology in the interpretation of the Qur'an and his Qur’anic views regarding war and peace, this paper will attempt to show that the Qur’anic picture of war and peace is different from what is commonly supposed by non-Muslims. This paper will argue that since disagreement on the truth of religion is inevitable and perpetual; since imposition of religion is inconceivable; since the faithful have no responsibility for disbelievers’ choice except clearly delivering God’s Messages to them, and since the faithful are obliged to offer absolute respect to their disputants on the truth of religion, the reasonable way of managing disputes on religion is peaceful interaction between Muslims and non-Muslims. It will be further argued that in addition to the moral principle of peace, there is another ground on the basis of which Muslims are advised to establish peaceful relations with non-Muslims; that is, through making peace contracts. In this way, the principle of peace is reinforced by the duty of respecting peace contracts

The Worst-Case Scenario and Discounting the Very Long Term

We propose an ethical viewpoint based on the possibility of the realization of the worst-case scenario in order to reduce future generations risks in terms of discounting. Applied to the question of conservation of a renewable resource, we show that an economy, where the social planner takes into account the possibility that at an uncertain date the discount rate could change to its minimum possible value, could lead to a better conservation of the resource and modify the position of the sacrificed generations. Finally, our model suggests to apply the lowest possible discount rate immediately for long term environmental projects.Discounting ; environment ; uncertainty ; preservation of natural resources ; intergenerational equity.