Experimental study of pedestrian flow through a bottleneck

In this work the results of a bottleneck experiment with pedestrians are presented in the form of total times, fluxes, specific fluxes, and time gaps. A main aim was to find the dependence of these values from the bottleneck width. The results show a linear decline of the specific flux with increasing width as long as only one person at a time can pass, and a constant value for larger bottleneck widths. Differences between small (one person at a time) and wide bottlenecks (two persons at a time) were also found in the distribution of time gaps.Comment: accepted for publication in J. Stat. Mec

EBSD characterization of cryogenically rolled type 321 austenitic stainless steel

Electron backscatter diffraction was applied to investigate microstructure evolution during cryogenic rolling of type 321 metastable austenitic stainless steel. As expected, rolling promoted deformation-induced martensitic transformation which developed preferentially in deformation bands. Because a large fraction of the imposed strain was accommodated by deformation banding, grain refinement in the parent austenite phase was minimal. The martensitic transformation was found to follow a general orientation relationship, {111}γ||{0001}ε||{110}α′ and 〈110〉γ||〈11-20〉ε||〈111〉α′, and was characterized by noticeable variant selection

Martensite-to-austenite reversion and recrystallization in cryogenically-rolled type 321 metastable austenitic steel

The annealing behavior of cryogenically-rolled type 321 metastable austenitic steel was established. Cryogenic deformation gave rise to martensitic transformation which developed preferentially within deformation bands. Subsequent annealing in the range of 600 C to 700 C resulted in reversion of the strain-induced martensite to austenite. At 800 C, the reversion was followed by static recrystallization. At relatively-low temperatures, the reversion was characterized by a very strong variant selection, which led to the restoration of the crystallographic orientation of the coarse parent austenite grains. An increase in the annealing temperature relaxed the variant-selection tendency and provided subsequent recrystallization thus leading to significant grain refinement. Nevertheless, a significant portion of the original coarse grains was found to be untransformed and therefore the fine-grain structure was fairly heterogeneous

Rural Decline and the Farm Crisis: Two Marginally Related Issues

The current crisis in Canadian agriculture is well documented. Researchers are pointing to the declining ability of farmers to support local communities as a result of cost-price squeezes and high debt loads. These problems have been directly associated with the rural community crisis, which in Alberta is one of dwindling populations, an aging demographic base and depressed local economies. There is little doubt that the crisis in these two sectors is real, but the suggested linkages between them are open to question. The survivability of rural communities is not exclusively tied to agricultural profits. While beleaguered Alberta farmers seem to be compounding their reduced spending .by trading with nearby cities rather than the local community, of even greater relevance is the presence of industries which encourage population growth. Agriculture is no longer a major contributor to the creation of rural employment, particularly in prairie Canada where the technologies of extensive production have replaced labor inputs with capital investment. The argument being presented here is that the crisis of rural communities is related to the crisis in agriculture only to the extent of reduced local spending. This is a serious problem, but the major issue is one of dwindling populations. The decline of agricultural jobs in Alberta is for the most part, not the product of the crisis. To the contrary, it represents a long term trend toward mechanization and increased efficiency. Studies conducted in this province suggest that the survival of rural communities is increasingly tied to urban economies and values. Those communities which are able to attract urban industrial developments or provide a residential base for urban workers clearly show the greatest propensity for future growth. Inevitably this is producing a spatial bias in their distribution across the rural landscape