Chalk in the prime.

Human Geophagia, Calabash Chalk and Undongo: Mineral Element Nutritional Implications

The prime aim of our work is to report and comment on the bioaccessible concentrations - i.e., the soluble content of chemical elements in the gastrointestinal environment that is available for absorption - of a number of essential mineral nutrients and potentially harmful elements (PHEs) associated with the deliberate ingestion of African geophagical materials, namely Calabash chalk and Undong...

Devensian periglacial influences on the development of spatially variable permeability in the Chalk of southeast England

In unconfined parts of the Chalk aquifer in southeast England, permeability generally varies laterally with the lowest permeabilities occurring beneath interfluve areas, and the highest beneath river valleys and dry valleys. Furthermore, the Chalk in the river valleys is normally in excellent hydraulic continuity with the overlying highly permeable Quaternary gravels. However, recent field inve...

SNO Calibration Source Optimization AECL Research NCMS Branch Chalk River Laboratories Chalk River

Mechanical Behaviour of Chalk Reservoirs: Numerical Modelling of Water Sensitivity Effects

Chalk is the constituent material of numerous oil reservoirs in North Sea. The mechanical behaviour of a saturated chalk has been largely studied. However, different aspects of its behaviour are not yet well understood: material characteristics depend on the saturating fluids and chalk response is timedependent. This paper proposes the PASACHALK numerical model: an elasto-plastic constitutive l...

The effect of chalk on the finger-hold friction coefficient in rock climbing.

The main purpose of this study was to examine the effect of chalk on the friction coefficient between climber's fingers and two different rock types (sandstone and limestone). The secondary purpose was to investigate the effects of humidity and temperature on the friction coefficient and on the influence of chalk. Eleven experienced climbers took part in this study and 42 test sessions were per...