Winning strategies in congested traffic

One-directional traffic on two-lanes is modeled in the framework of a spring-block type model. A fraction $q$ of the cars are allowed to change lanes, following simple dynamical rules, while the other cars keep their initial lane. The advance of cars, starting from equivalent positions and following the two driving strategies is studied and compared. As a function of the parameter $q$ the winning probability and the average gain in the advancement for the lane-changing strategy is computed. An interesting phase-transition like behavior is revealed and conclusions are drawn regarding the conditions when the lane changing strategy is the better option for the drivers.Comment: 5 pages, 5 figure

Spring-block approach for nanobristle patterns

A two dimensional spring-block type model is used to model capillarity driven self-organization of nanobristles. The model reveals the role of capillarity and van der Waals forces in the pattern formation mechanism. By taking into account the relevant interactions several type of experimentally observed patterns are qualitatively well reproduced. The model offers the possibility to generate on computer novel nanobristle based structures, offering hints for designing further experiments.Comment: 6 pages, 6 figure

Statističke analogije između potresa, mikropotresa u metalima i lavina u 1D Burridge-Knopoff modelu

Universalities and intriguing analogies in the statistics of avalanches are revealed for three physical systems defined on largely different length and energy scales. Earthquakes induced by tectonic scale dynamics, micro-scale level quakes observed from slipping crystallographic planes in metals and a one-dimensional, room-scale spring-block type Burridge-Knopoff model is studied from similar statistical viewpoints. The validity of the Gutenberg-Richter law for the probability density of the energies dissipated in the avalanches is proven for all three systems. By analysing data for three different seismic zones and performing acoustic detection for different Zn samples under deformation, universality for the involved scaling exponent is revealed. With proper parameter choices the 1D Burridge-Knopoff model is able to reproduce the same scaling law. The recurrence times of earthquakes and micro-quakes with magnitudes above a given threshold present again similar distributions and striking quantitative similarities. However, the 1D Burridge-Knopoff model cannot account for the correlations observed in such statistics.Univerzalnosti i intrigantne analogije u statistici lavina otkrivene su za tri fizička sustava definirana na uvelike različitim duljinama i energijskim skalama. Potresi uzrokovani dinamikom na tektonskoj skali, mikro-potresi koji nastaju na klizećim kristalografskim ravnina u metalima i jednodimenzionalni Burridge-Knopoffov model opruga i blokova na skali sobe proučeni su sa sličnih statističkih stajališta. Valjanost Gutenberg-Richterove relacije za gustoću vjerojatnosti energija disipirane u lavinama dokazana je za sva tri sustava. Analizom podataka za tri različita seizmički aktivna područja i detekcijom akustičkih valova za različite uzorke Zn pod deformacijom, otkrivena je univerzalnost za uključeni eksponent skaliranja. S pravilnim izborom parametara 1D Burridge-Knopoffov model može reproducirati isti zakon skaliranja. Vremena ponavljanja potresa i mikropotresa s magnitudama iznad zadanog praga opet predstavljaju slične distribucije i zapanjujuće kvantitativne sličnosti. Međutim, 1D Burridge-Knopoffov model ne može objasniti korelacije opažene u takvim statistikama

Theoretical investigations on the projectile coherence effects in fully differential ionization cross sections

We propose a theoretical investigation method for testing the effect of the projectile beam coherence on single ionization processes in light atoms. The method is carried out in the framework of a first-order approximation, and the results are tested for single ionization of helium produced by fast charged projectiles. Based on the same ionization amplitudes fully differential cross section calculations are performed for coherent and incoherent projectile beams. Projectile coherence effects are investigated through these fully differential cross sections and the interference effects are evidenced through cross section ratios. The obtained results are compared to the available experimental data. By these calculations we confirm that projectile coherence effects may have important role in these ionization processes

Chaos on the conveyor belt

The dynamics of a spring-block train placed on a moving conveyor belt is investigated both by simple experiments and computer simulations. The first block is connected by a spring to an external static point and, due to the dragging effect of the belt, the blocks undergo complex stick-slip dynamics. A qualitative agreement with the experimental results can be achieved only by taking into account the spatial inhomogeneity of the friction force on the belt's surface, modeled as noise. As a function of the velocity of the conveyor belt and the noise strength, the system exhibits complex, self-organized critical, sometimes chaotic, dynamics and phase transition-like behavior. Noise-induced chaos and intermittency is also observed. Simulations suggest that the maximum complexity of the dynamical states is achieved for a relatively small number of blocks (around five)