Concentration change, spatial

The time savings and improved spatial resolution of MRI measurements over traditional measurements are profound advantages of MRI. MRI can provide similar information in less than 1 h when literally it would otherwise require days. This would be of particular interest in diffusion type experiments where spatial concentration changes with time are measured. In addition, the same sample can be... 

This law states that the local concentration change with time due to a diffusive transport process is proportional to the second spatial derivative of the concentration. 

In summary, it is clear that amoebae can spatially discriminate receptor binding of chemoattractant. However, the importance of temporal concentration changes for chemotaxis is still unresolved. 

Apart from this change in boundary condition, the simulation space for a microband array is exactly the same as for the single microband, depicted in Figure 9.8. As with the microdisc array, it is necessary to alter the spatial grid in the X-direction so that there is a high concentration of spatial points at this outer boundary to ensure accurate simulation. 

The kinetics of dissolution of ionic solids has traditionally been studied via the measurement of bulk concentration changes in, for example, stirred suspensions. Using the equilibrium perturbation mode of the SECM, the experimenter can control directly the interfacial undersaturation and make measurements at single crystal surfaces or with micrometer spatial resolution [24]. 

The main challenge in combustion research lies in the need to make a large number of measurements simultaneously. First, it is essential to know how well the fuel and air are mixed, together with their spatial and temporal distributions in the combustion chamber. Second, the spatial and temporal variations in temperature must be measured. Third, the large number of chemical intermediates, whose concentration changes rapidly with time, has to be determined. 

The ecophysiological aspects of Antillean dry forests that we have just reviewed reveal complex adaptations to the diverse environmental conditions typical of these forests. The environmental complexity is revealed in a list of conditions that change spatially and temporally. For example (1) variable gradients of soil moisture, (2) variable nutrient availability, (3) chemical challenges associated with high soil pH and calcium concentration, (4) pulses of resource availability associated with temperature and rainfall seasonality, (5) limited space for tree anchorage and roots due to rocky soils, (6) periodic hurricanes and others. 

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