Energy-Momentum Complex in M\o ller's Tetrad Theory of Gravitation

M\o ller's Tetrad Theory of Gravitation is examined with regard to the energy-momentum complex. The energy-momentum complex as well as the superpotential associated with M\o ller's theory are derived. M\o ller's field equations are solved in the case of spherical symmetry. Two different solutions, giving rise to the same metric, are obtained. The energy associated with one solution is found to be twice the energy associated with the other. Some suggestions to get out of this inconsistency are discussed at the end of the paper.Comment: LaTeX2e with AMS-LaTeX 1.2, 13 page

The Effect Of Delay Times On The Optimal Velocity Traffic Flow Behavior

We have numerically investigated the effect of the delay times $\tau_f$ and $\tau_s$ of a mixture of fast and slow vehicles on the fundamental diagram of the optimal velocity model. The optimal velocity function of the fast cars depends not only on the headway of each car but also on the headway of the immediately preceding one. It is found that the small delay times have almost no effects, while, for sufficiently large delay time $\tau_s$ the current profile displays qualitatively five different forms depending on $\tau_f$, $\tau_s$ and the fractions $d_f$ and $d_s$ of the fast and slow cars respectively. The velocity (current) exhibits first order transitions at low and/or high densities, from freely moving phase to the congested state, and from congested state to the jamming one respectively accompanied by the existence of a local minimal current. Furthermore, there exist a critical value of $\tau_f$ above which the metastability and hysteresis appear. The spatial-temporal traffic patterns present more complex structur

A simulation study of an asymmetric exclusion model with disorder

On the one hand, using numerical simulations, we study the asymmetric exclusion model with open boundaries, particlewise disorder. The phase diagram in the (α , β)   -plane displays high density, low density and maximum current phases, with the first order transition line between high and low density phases shifted away from the line α =β. Within the low density phase a platoon phase transition occurs, many features of which can be explained using exact results for asymmetric exclusion with particlewise disorder on the ring. In a certain region of parameter space the disorder induces a cusp in the current-density relation at maximum flow. Our simulations indicate that this does not affect the topology of the phase diagram, nor the familiar 1/Öx -decay of the density profile in the maximum current phase. On the other hand, we study the effects of defects in the road and of jumping rate ∆t on the phase diagram J−ρ, using asymmetric exclusion model with periodic boundaries. For different level of disorder, the space-time evolution of particles displays «waves» for both phases low density and high density. Besides, there exist two critical values of density, a lower critical value ρc1 and a upper critical value ρc2, in between the current is constant and reaches its maximal value Jmax which increases with increasing the jumping rate ∆t and/or the degree of disorder c. Increasing ∆t and/or c, ρc1 increases and ρc2 decreases.On the one hand, using numerical simulations, we study the asymmetric exclusion model with open boundaries, particlewise disorder. The phase diagram in the (α , β)   -plane displays high density, low density and maximum current phases, with the first order transition line between high and low density phases shifted away from the line α =β. Within the low density phase a platoon phase transition occurs, many features of which can be explained using exact results for asymmetric exclusion with particlewise disorder on the ring. In a certain region of parameter space the disorder induces a cusp in the current-density relation at maximum flow. Our simulations indicate that this does not affect the topology of the phase diagram, nor the familiar 1/Öx -decay of the density profile in the maximum current phase. On the other hand, we study the effects of defects in the road and of jumping rate ∆t on the phase diagram J−ρ, using asymmetric exclusion model with periodic boundaries. For different level of disorder, the space-time evolution of particles displays «waves» for both phases low density and high density. Besides, there exist two critical values of density, a lower critical value ρc1 and a upper critical value ρc2, in between the current is constant and reaches its maximal value Jmax which increases with increasing the jumping rate ∆t and/or the degree of disorder c. Increasing ∆t and/or c, ρc1 increases and ρc2 decreases

On singular Lagrangians affine in velocities

The properties of Lagrangians affine in velocities are analyzed in a geometric way. These systems are necessarily singular and exhibit, in general, gauge invariance. The analysis of constraint functions and gauge symmetry leads us to a complete classification of such Lagrangians.Comment: AMSTeX, 22 page

Correlation between microstructure and electric properties in SnO(2) rich enamels

No abstract availabl

An Insight into Life at Geometric Zagora Provided by the Animal Bones

This thesis is a study of the animal bone distribution at the Geometric period settlement of Zagora (ca. 850-700 BC), on the island of Andros. The animal bones were excavated during the 1967-74 University of Sydney excavations and analysed in 1977 by a specialist who compiled a report of her findings. The report is currently in preparation for publication and is the primary source for this thesis. The data it provided was limited but enough could be extracted to identify patterns that permitted a tentative reconstruction of social life and the economy at Zagora. There is a paucity of excavated settlements from the Greek EIA and few of these have published faunal material, an essential element in reconstructing past lifeways. Those preserved settlements from which animal bones have been published are not extensive with good domestic contexts but usually sites of minimal extent. Hence, it has not been possible to conduct an analysis of the spatial distribution of animal bones from such a settlement. Zagora, being an extensive settlement containing mainly domestic structures, is therefore unique and the animal bone report provided the opportunity for such a study to be undertaken. A number of analyses were performed using both statistical and non-statistical methods. Through these it was discovered that there is a relationship between the animal size and the size of the architectural unit within which it was found. Similarly, there appeared to be a relationship between larger architecture and the presence of fish, postulated as being a pelagic species. The patterns observed were interpreted as evidence of ‘special’ meals with a larger than usual number of diners in attendance and hence the need for a larger space to host them. Using the animal bones’ distribution and architectural evidence it is proposed that feasting was an important event at Zagora, conducted at the household level to possibly reinforce bonds of kinship and friendship. The evidence also suggests that the H area could have been inhabited by people of better means than elsewhere in the settlement, particularly by the hypaethral sanctuary. Ideally the animal bones would have been studied in conjunction with associated artefacts, but this was not possible and so this would be something desirable to be performed in the near future. With 21st century excavation techniques, the future Zagora excavations should provide greater granularity in the faunal information obtained from the settlement to allow better precision in subsequent analyses

Inspiratory muscle warm-up does not improve cycling time-trial performance

Purpose: This study examined the effects of an active cycling warm-up, with and without the addition of an inspiratory muscle warm-up (IMW), on 10-km cycling time-trial performance