Scaling of Fracture Strength in Disordered Quasi-Brittle Materials

This paper presents two main results. The first result indicates that in materials with broadly distributed microscopic heterogeneities, the fracture strength distribution corresponding to the peak load of the material response does not follow the commonly used Weibull and (modified) Gumbel distributions. Instead, a {\it lognormal} distribution describes more adequately the fracture strengths corresponding to the peak load of the response. Lognormal distribution arises naturally as a consequence of multiplicative nature of large number of random distributions representing the stress scale factors necessary to break the subsequent "primary" bond (by definition, an increase in applied stress is required to break a "primary" bond) leading up to the peak load. Numerical simulations based on two-dimensional triangular and diamond lattice topologies with increasing system sizes substantiate that a {\it lognormal} distribution represents an excellent fit for the fracture strength distribution at the peak load. The second significant result of the present study is that, in materials with broadly distributed microscopic heterogeneities, the mean fracture strength of the lattice system behaves as $\mu_f = \frac{\mu_f^\star}{(Log L)^\psi} + \frac{c}{L}$, and scales as $\mu_f \approx \frac{1}{(Log L)^\psi}$ as the lattice system size, $L$, approaches infinity.Comment: 24 pages including 11 figure

Regional (im)balances in transitional economies: The Croatian case

In this paper we attempt to give answer on the following question: what is the way in which transitional process influence on the balance of the regional development of the transitional countries. In order to give answer on this question we will analyze Croatian regional processes in the pre transitional as well as in the transitional period divided in the following sub periods: 1965-1975; 1975-1990; 1990-1995. In this analysis we will examine position of the 22 Croatian counties individually and summary implementing 32 indicators based on the PROMETEE method. Since indicators are from the economic, natural and socio-cultural origin we consider this analysis to be integral one.

Explosive Remnants of War in the Republic of Croatia

Explosive remnants of war represent a constant threat to normal life and activities of the population living in mine-affected areas in the Republic of Croatia. The author considers the extent and impact of unexploded ordnance and other ERW contaminating the country as a consequence of military operations between 1991 and 1995

A Novel Method for Determination of Kinetic Friction Coefficient using Inclined Plane

Presented in this paper is the theoretical background for a novel method for determination of kinetic friction coefficient. The method is based on the equation of movement of a rigid body along an inclined plane and has not been previously discussed in literature. According to the theoretical results presented in this paper, mean kinetic friction coefficient can be determined based on the time it takes a rigid body to travel a distance along an inclined plane. Experimental results show that the mean kinetic friction coefficient increases with increasing mean sliding velocity, i.e. with decreasing sliding time. Increasing sliding velocity increases deviation of friction coefficients. This method also allows the determination of energy consumed due to friction along the travelled distance. Increasing mean kinetic friction coefficient and mean sliding velocity increases energy consumed due to friction. Practical calculation requires application of the distance law, which, in turn, requires accurate measurement of the sliding time and distance

Preemptive strike: An experimental study of fear-based aggression

AbstractThe mere presence of a potential threat of attack was found to be sufficient to lead a significant proportion of participants to engage in preemptive attacks toward potential threats; this response occurred even without an incentive for either party to attack the other. We developed a new experimental game—the preemptive strike game (PSG)—to demonstrate this tendency for defensive aggression. We also found that the rate at which participants attacked an individual representing a potential threat was not influenced by their minimal group membership; participants were no less likely to preemptively attack a member of their own minimal group and no more likely to use aggression against members of another minimal group. These findings indicate a need to further examine the role that fear-based defensive aggression, rather than anger-based spiteful aggression, plays in inter-individual and inter-group conflict